Christmas Eve/Day Storm System
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The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K.
What does the EC say?
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The above post and any post by Ntxw is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including Storm2k. For official information, please refer to NWS products.
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brunota2003
- S2K Supporter
- Posts: 9476
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Re: Christmas Eve/Day Storm System
Afternoon update from Jackson, KY:
/TONIGHT THROUGH THURSDAY/
19Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE FURTHER RETREATING TO THE
EAST OUT OF KENTUCKY AHEAD OF A LARGE AND DEVELOPING AREA OF LOW
PRESSURE OVER THE SOUTHERN PLAINS. HIGH CLOUDS ARE PUSHING INTO THE
OHIO VALLEY FROM THIS LOW WHILE OTHERS ARE MOVING OUT OF THE AREA TO
THE NORTHEAST FROM A PASSING...FLAT...SHORT WAVE. A GOOD AMOUNT OF
SUNSHINE TODAY HAS RESULTED IN GOOD MELTING OF THE SNOW COVER. IN
LOCATIONS WITHOUT MUCH SNOW...LIKE MONTICELLO AND SOMERSET...
TEMPERATURES CLIMBED TOWARD 50 DEGREES THIS AFTERNOON...ELSEWHERE
READINGS MADE IT TO THE LOWER AND MIDDLE 40S. DEWPOINTS REMAIN
FAIRLY MOIST...GENERALLY IN THE MIDDLE 30S.
THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH RIDGING BUILDING OVER
THE REGION TONIGHT AND WEDNESDAY IN RESPONSE TO A DEEP DIVING TROUGH
CURLING INTO THE TEXAS PANHANDLE. IT IS AFTER THIS POINT...00Z
THURSDAY...THAT LARGER DIFFERENCES CROP INTO THE SOLUTIONS WITH THE
NAM SIGNIFICANTLY SLOWER MOVING THE DEVELOPING UPPER LOW EAST
COMPARED TO THE GFS AND NEW ECMWF. AS SUCH...IT HAS BEEN DISCOUNTED
AFTER ABOUT 24 HOURS. FOR THURSDAY...THE UPPER LOW PULLS IN A
TRAILING AND ALSO QUITE STRONG CLOSED LOW TO BEGIN ITS DESTINED
CONSOLIDATION INTO A DEEP CLOSED LOW OVER THE EASTERN PLAINS. AS
THIS TRANSITION TAKES PLACE...THE ECMWF IS FURTHEST EAST AND A BIT
STRONGER WITH THE LEAD LOW THAN THE GFS WHILE THE GFS/S FOLLOWING
AND REINFORCING LOW ARRIVES A BIT QUICKER IN ITS SCENARIO.
REGARDLESS OF HOW THESE FEATURES COMBINE THE END RESULT IS NEARLY
THE SAME WITH A POWERFUL AND DEEP UPPER LOW DOMINATING THE HEART OF
THE COUNTRY BY FRIDAY MORNING. FOR THE LATTER PART OF THE SHORT TERM
PORTION OF THE FORECAST...FOLLOWED A BLEND OF THE GFS AND ECMWF WX
SPECIFICS OWING TO THEIR PREFERRED UPPER LEVEL SOLUTIONS.
AS FOR SENSIBLE WEATHER...EXPECT THE HIGH CLOUDS FROM THE WEST TO
MOVE IN LATER TONIGHT AND THICKEN...LIKELY LIMITING THE RADIATIONAL
COOLING IN CONJUNCTION WITH CONTINUED MILD WAA. HOWEVER...THIS IS
ALSO COUNTERED IN MUCH OF THE CWA BY EXISTING PATCHES...LARGEST IN
THE EAST...OF SNOW. ACCORDINGLY...THE LOW TEMPERATURE FORECAST WILL
BE A CHALLENGE TONIGHT WITH ANY RIDGE THAT HAS MANAGED TO LOSE MOST
OF ITS SNOW ENDING UP THE WARMEST...SOME COLD VALLEY LOCATIONS...
PARTICULARLY EAST...AND ELSEWHERE LOWS JUST BELOW FREEZING AS
MELTING OF THE SNOW PACK CONTINUES TO PROVIDE HIGH HUMIDITIES WELL
THROUGH THE NIGHT. THIS MELTING WILL ALSO LIKELY CONTRIBUTE TO FOG
DEVELOPING ON THE RIDGETOPS LATE TONIGHT...BUT PROBABLY NOT TO THE
EXTENT WE SAW EARLY THIS MORNING. EXPECT A DAY SIMILAR TO TODAY ON
WEDNESDAY WITH WAA CONTINUING TO SUPPORT TEMPERATURES REBOUNDING
INTO THE UPPER 40S AND LOWER 50S...DESPITE LESS SUNSHINE. LATE IN
THE DAY AND INTO THE WEDNESDAY NIGHT A FEW STRAY SHOWER WILL BE
POSSIBLE AS THE LARGE...BECOMING STACKED...SFC LOW SPINS WELL TO OUR
WEST AND A DEVELOPING WARM FRONT APPROACHES THE AREA. THIS THREAT OF
ISOLATED TO SCATTERED SHOWERS WEDNESDAY NIGHT WILL COMBINE WITH
STILL COLD VALLEY LOCATIONS IN THE FAR EAST FOR A VERY SLIGHT CHANCE
OF FREEZING RAIN TOWARD DAWN THURSDAY. THOUGH THIS WILL NOT BE A
SIGNIFICANT WEATHER FACTOR...WILL MENTION THE RISK IN THE HWO AND
HINT AT IT IN THE FAR EAST ZONES THAT CARRY POPS. FOR THURSDAY...
TEMPERATURES WILL CLIMB INTO THE LOWER AND MIDDLE 50S MOST LOCATIONS
WITH THE WINDS PICKING UP BETTER FROM THE SOUTH...GUSTY AT
TIMES...CONTINUING THE MELTING OF REMAINING SNOW. FOLLOWING THE
BLENDED SOLUTION OF THE GFS AND ECMWF...SHOWERS SHOULD BE PUSHING
MORE FORCEFULLY INTO THE WESTERN PORTION OF EAST KENTUCKY BY LATE
AFTERNOON AS THE SYSTEM/S LARGE OCCLUDED/COLD FRONT STARTS TO SWEEP
EAST THROUGH KENTUCKY WITH INCREASED ALACRITY.
AS FOR TEMPS...FOLLOWED A BLEND OF THE GUIDANCE THROUGH THE
PERIOD...BUT WITH SIGNIFICANT MODIFICATION FOR BOTH RELATIVE TERRAIN
AT NIGHT AND EXISTING SNOW COVER THROUGH AT LEAST WEDNESDAY NIGHT.
WITH THE POPS...ENDED UP CLOSEST TO THE MAV NUMBERS THROUGH
WEDNESDAY...THEN WAS MOST SIMILAR TO THE NUMBERS FROM THE MAV INTO
THURSDAY.
.LONG TERM.../THURSDAY NIGHT THROUGH TUESDAY/
THE FOCUS FOR THE PERIOD IS ON A STRENGTHENING LOW PRESSURE SYSTEM
OVER THE UPPER MIDWEST WHICH IS EXPECTED TO FORCE A COLD FRONT
THROUGH EASTERN KENTUCKY FRIDAY MORNING. THE MAIN IMPACTS EXPECTED
WITH THIS SYSTEM CONTINUE TO BE A BRIEF PERIOD OF HEAVY RAINFALL AND
GUSTY WINDS.
QPF FROM AVAILABLE MODELS REMAINS LESS THAN AN INCH FOR THE AREA
THURSDAY NIGHT INTO FRIDAY MORNING AND RAIN SHADOWING EFFECT FROM
SOUTHEAST LOW LEVEL WINDS WILL PROBABLY MEAN LESS THAN A HALF INCH
OVER THE UPPER REACHES OF THE CUMBERLAND... KENTUCKY AND BIG SANDY
BASINS IN OUR AREA. DO NOT EXPECT ANY WIDESPREAD WATER PROBLEMS FROM
THIS AMOUNT OF RAIN COMBINED WITH CONTINUED SNOW MELT FROM OUR
RATHER LARGE HIGHER ELEVATION SNOW PACK... ALTHOUGH RIVERS WILL RUN
HIGH.
THE WIND THREAT ALSO LOOKS MINIMAL AS TIGHTEST PRESSURE GRADIENT
REMAINS TO OUR NORTHWEST THURSDAY NIGHT AND FRIDAY. THIS IS A
FAVORABLE SETUP FOR MOUNTAIN WAVE ACTIVITY OFF BLACK MOUNTAIN THOUGH
LATE THURSDAY NIGHT WITH A POTENT (50-KT PLUS) 850 MB JET PROGGED
AND PERPENDICULAR FLOW AT MOUNTAIN TOP LEVEL. LOCALIZED ADVISORY
CRITERIA WINDS OR GREATER WILL THUS BE POSSIBLE ACROSS EXTREME
SOUTHEAST KENTUCKY... BUT WILL HAVE TO MONITOR FUTURE MODEL RUNS TO
BETTER DEFINE THE THREAT.
OTHERWISE... PROGS REMAIN CONSISTENT IN BRINGING IN A MUCH COLDER
AIR MASS BEHIND THIS SYSTEM LATE FRIDAY THROUGH MONDAY AT LEAST.
LATEST GUIDANCE IS SLOWER IN EJECTING THE UPPER LOW TO OUR NORTHEAST
WITH OPERATIONAL GUIDANCE DEEPER AND FURTHER SOUTH THAN NAEFS MEAN.
NONETHELESS... A PERIOD OF MUCH BELOW NORMAL TEMPERATURES APPEARS
LIKELY THROUGH THE WEEKEND. PROGGED WEST TO SOUTHWEST MEAN LOW-LEVEL
FLOW IS NOT FAVORABLE FOR UPSLOPE SNOW SHOWER ACTIVITY... BUT WE
WILL MAINTAIN AT LEAST A 20 POP FROM FRIDAY NIGHT THROUGH MONDAY AS
PINWHEELING SHORTWAVES AROUND UPPER LOW TO THE NORTH WILL LIKELY
BRING A SNOW SHOWER FROM TIME TO TIME.
THE UPPER LOW IS EXPECTED TO FINALLY WEAKEN/MOVE TO OUR NORTHEAST
EARLY NEXT WEEK. SURFACE HIGH PRESSURE MAY EVEN HAVE A CHANCE TO
BUILD INTO THE AREA BY TUESDAY WITH A BIT OF A WARM UP EXPECTED.
ANOTHER SOUTHERN STREAM SYSTEM IS THEN PROGGED TO BEGIN ORGANIZING
TO OUR SOUTHWEST... BUT ITS IMPACTS ON OUR AREA... IF ANY... WILL
LIKELY NOT BE FELT UNTIL NEXT WEDNESDAY OR LATER.
/TONIGHT THROUGH THURSDAY/
19Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE FURTHER RETREATING TO THE
EAST OUT OF KENTUCKY AHEAD OF A LARGE AND DEVELOPING AREA OF LOW
PRESSURE OVER THE SOUTHERN PLAINS. HIGH CLOUDS ARE PUSHING INTO THE
OHIO VALLEY FROM THIS LOW WHILE OTHERS ARE MOVING OUT OF THE AREA TO
THE NORTHEAST FROM A PASSING...FLAT...SHORT WAVE. A GOOD AMOUNT OF
SUNSHINE TODAY HAS RESULTED IN GOOD MELTING OF THE SNOW COVER. IN
LOCATIONS WITHOUT MUCH SNOW...LIKE MONTICELLO AND SOMERSET...
TEMPERATURES CLIMBED TOWARD 50 DEGREES THIS AFTERNOON...ELSEWHERE
READINGS MADE IT TO THE LOWER AND MIDDLE 40S. DEWPOINTS REMAIN
FAIRLY MOIST...GENERALLY IN THE MIDDLE 30S.
THE MODELS ARE IN DECENT AGREEMENT ALOFT WITH RIDGING BUILDING OVER
THE REGION TONIGHT AND WEDNESDAY IN RESPONSE TO A DEEP DIVING TROUGH
CURLING INTO THE TEXAS PANHANDLE. IT IS AFTER THIS POINT...00Z
THURSDAY...THAT LARGER DIFFERENCES CROP INTO THE SOLUTIONS WITH THE
NAM SIGNIFICANTLY SLOWER MOVING THE DEVELOPING UPPER LOW EAST
COMPARED TO THE GFS AND NEW ECMWF. AS SUCH...IT HAS BEEN DISCOUNTED
AFTER ABOUT 24 HOURS. FOR THURSDAY...THE UPPER LOW PULLS IN A
TRAILING AND ALSO QUITE STRONG CLOSED LOW TO BEGIN ITS DESTINED
CONSOLIDATION INTO A DEEP CLOSED LOW OVER THE EASTERN PLAINS. AS
THIS TRANSITION TAKES PLACE...THE ECMWF IS FURTHEST EAST AND A BIT
STRONGER WITH THE LEAD LOW THAN THE GFS WHILE THE GFS/S FOLLOWING
AND REINFORCING LOW ARRIVES A BIT QUICKER IN ITS SCENARIO.
REGARDLESS OF HOW THESE FEATURES COMBINE THE END RESULT IS NEARLY
THE SAME WITH A POWERFUL AND DEEP UPPER LOW DOMINATING THE HEART OF
THE COUNTRY BY FRIDAY MORNING. FOR THE LATTER PART OF THE SHORT TERM
PORTION OF THE FORECAST...FOLLOWED A BLEND OF THE GFS AND ECMWF WX
SPECIFICS OWING TO THEIR PREFERRED UPPER LEVEL SOLUTIONS.
AS FOR SENSIBLE WEATHER...EXPECT THE HIGH CLOUDS FROM THE WEST TO
MOVE IN LATER TONIGHT AND THICKEN...LIKELY LIMITING THE RADIATIONAL
COOLING IN CONJUNCTION WITH CONTINUED MILD WAA. HOWEVER...THIS IS
ALSO COUNTERED IN MUCH OF THE CWA BY EXISTING PATCHES...LARGEST IN
THE EAST...OF SNOW. ACCORDINGLY...THE LOW TEMPERATURE FORECAST WILL
BE A CHALLENGE TONIGHT WITH ANY RIDGE THAT HAS MANAGED TO LOSE MOST
OF ITS SNOW ENDING UP THE WARMEST...SOME COLD VALLEY LOCATIONS...
PARTICULARLY EAST...AND ELSEWHERE LOWS JUST BELOW FREEZING AS
MELTING OF THE SNOW PACK CONTINUES TO PROVIDE HIGH HUMIDITIES WELL
THROUGH THE NIGHT. THIS MELTING WILL ALSO LIKELY CONTRIBUTE TO FOG
DEVELOPING ON THE RIDGETOPS LATE TONIGHT...BUT PROBABLY NOT TO THE
EXTENT WE SAW EARLY THIS MORNING. EXPECT A DAY SIMILAR TO TODAY ON
WEDNESDAY WITH WAA CONTINUING TO SUPPORT TEMPERATURES REBOUNDING
INTO THE UPPER 40S AND LOWER 50S...DESPITE LESS SUNSHINE. LATE IN
THE DAY AND INTO THE WEDNESDAY NIGHT A FEW STRAY SHOWER WILL BE
POSSIBLE AS THE LARGE...BECOMING STACKED...SFC LOW SPINS WELL TO OUR
WEST AND A DEVELOPING WARM FRONT APPROACHES THE AREA. THIS THREAT OF
ISOLATED TO SCATTERED SHOWERS WEDNESDAY NIGHT WILL COMBINE WITH
STILL COLD VALLEY LOCATIONS IN THE FAR EAST FOR A VERY SLIGHT CHANCE
OF FREEZING RAIN TOWARD DAWN THURSDAY. THOUGH THIS WILL NOT BE A
SIGNIFICANT WEATHER FACTOR...WILL MENTION THE RISK IN THE HWO AND
HINT AT IT IN THE FAR EAST ZONES THAT CARRY POPS. FOR THURSDAY...
TEMPERATURES WILL CLIMB INTO THE LOWER AND MIDDLE 50S MOST LOCATIONS
WITH THE WINDS PICKING UP BETTER FROM THE SOUTH...GUSTY AT
TIMES...CONTINUING THE MELTING OF REMAINING SNOW. FOLLOWING THE
BLENDED SOLUTION OF THE GFS AND ECMWF...SHOWERS SHOULD BE PUSHING
MORE FORCEFULLY INTO THE WESTERN PORTION OF EAST KENTUCKY BY LATE
AFTERNOON AS THE SYSTEM/S LARGE OCCLUDED/COLD FRONT STARTS TO SWEEP
EAST THROUGH KENTUCKY WITH INCREASED ALACRITY.
AS FOR TEMPS...FOLLOWED A BLEND OF THE GUIDANCE THROUGH THE
PERIOD...BUT WITH SIGNIFICANT MODIFICATION FOR BOTH RELATIVE TERRAIN
AT NIGHT AND EXISTING SNOW COVER THROUGH AT LEAST WEDNESDAY NIGHT.
WITH THE POPS...ENDED UP CLOSEST TO THE MAV NUMBERS THROUGH
WEDNESDAY...THEN WAS MOST SIMILAR TO THE NUMBERS FROM THE MAV INTO
THURSDAY.
.LONG TERM.../THURSDAY NIGHT THROUGH TUESDAY/
THE FOCUS FOR THE PERIOD IS ON A STRENGTHENING LOW PRESSURE SYSTEM
OVER THE UPPER MIDWEST WHICH IS EXPECTED TO FORCE A COLD FRONT
THROUGH EASTERN KENTUCKY FRIDAY MORNING. THE MAIN IMPACTS EXPECTED
WITH THIS SYSTEM CONTINUE TO BE A BRIEF PERIOD OF HEAVY RAINFALL AND
GUSTY WINDS.
QPF FROM AVAILABLE MODELS REMAINS LESS THAN AN INCH FOR THE AREA
THURSDAY NIGHT INTO FRIDAY MORNING AND RAIN SHADOWING EFFECT FROM
SOUTHEAST LOW LEVEL WINDS WILL PROBABLY MEAN LESS THAN A HALF INCH
OVER THE UPPER REACHES OF THE CUMBERLAND... KENTUCKY AND BIG SANDY
BASINS IN OUR AREA. DO NOT EXPECT ANY WIDESPREAD WATER PROBLEMS FROM
THIS AMOUNT OF RAIN COMBINED WITH CONTINUED SNOW MELT FROM OUR
RATHER LARGE HIGHER ELEVATION SNOW PACK... ALTHOUGH RIVERS WILL RUN
HIGH.
THE WIND THREAT ALSO LOOKS MINIMAL AS TIGHTEST PRESSURE GRADIENT
REMAINS TO OUR NORTHWEST THURSDAY NIGHT AND FRIDAY. THIS IS A
FAVORABLE SETUP FOR MOUNTAIN WAVE ACTIVITY OFF BLACK MOUNTAIN THOUGH
LATE THURSDAY NIGHT WITH A POTENT (50-KT PLUS) 850 MB JET PROGGED
AND PERPENDICULAR FLOW AT MOUNTAIN TOP LEVEL. LOCALIZED ADVISORY
CRITERIA WINDS OR GREATER WILL THUS BE POSSIBLE ACROSS EXTREME
SOUTHEAST KENTUCKY... BUT WILL HAVE TO MONITOR FUTURE MODEL RUNS TO
BETTER DEFINE THE THREAT.
OTHERWISE... PROGS REMAIN CONSISTENT IN BRINGING IN A MUCH COLDER
AIR MASS BEHIND THIS SYSTEM LATE FRIDAY THROUGH MONDAY AT LEAST.
LATEST GUIDANCE IS SLOWER IN EJECTING THE UPPER LOW TO OUR NORTHEAST
WITH OPERATIONAL GUIDANCE DEEPER AND FURTHER SOUTH THAN NAEFS MEAN.
NONETHELESS... A PERIOD OF MUCH BELOW NORMAL TEMPERATURES APPEARS
LIKELY THROUGH THE WEEKEND. PROGGED WEST TO SOUTHWEST MEAN LOW-LEVEL
FLOW IS NOT FAVORABLE FOR UPSLOPE SNOW SHOWER ACTIVITY... BUT WE
WILL MAINTAIN AT LEAST A 20 POP FROM FRIDAY NIGHT THROUGH MONDAY AS
PINWHEELING SHORTWAVES AROUND UPPER LOW TO THE NORTH WILL LIKELY
BRING A SNOW SHOWER FROM TIME TO TIME.
THE UPPER LOW IS EXPECTED TO FINALLY WEAKEN/MOVE TO OUR NORTHEAST
EARLY NEXT WEEK. SURFACE HIGH PRESSURE MAY EVEN HAVE A CHANCE TO
BUILD INTO THE AREA BY TUESDAY WITH A BIT OF A WARM UP EXPECTED.
ANOTHER SOUTHERN STREAM SYSTEM IS THEN PROGGED TO BEGIN ORGANIZING
TO OUR SOUTHWEST... BUT ITS IMPACTS ON OUR AREA... IF ANY... WILL
LIKELY NOT BE FELT UNTIL NEXT WEDNESDAY OR LATER.
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-
Siberian Express
- S2K Supporter
- Posts: 99
- Joined: Tue Sep 27, 2005 9:13 pm
- Location: Minnesota, USA
Re: Christmas Eve/Day Storm System
Well, whatever the models say it is gonna be a good snowmaker for parts.
"THIS STORM SYSTEM IS REMINISCENT OF THE INFAMOUS HALLOWEEN BLIZZARD
OF 1991."
That was one dynamic system. Huge snow, freezing rain and rain within a 100 miles
000
FXUS63 KMPX 231025
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
425 AM CST WED DEC 23 2009
.DISCUSSION...
ATTENTION IS DRAWN TO A LARGE CLOSED LOW NEAR THE FOUR CORNERS
REGION ON EARLY MORNING WATER VAPOR IMAGERY. THIS FEATURE WILL DIG
SOUTH/EAST TODAY...EJECT NORTH ON THURSDAY...AND UNITE WITH A
SECONDARY LOW SINKING SOUTH FROM SASKATCHEWAN ON FRIDAY. ANTECEDENT
WARM AIR ADVECTION AND ISENTROPIC UPGLIDE AHEAD OF THE PRIMARY LOW
HAVE INITIATED AREAS OF FREEZING DRIZZLE AND A FEW FLURRIES
OVERNIGHT ACROSS SOUTHERN MN. NAM/GFS INDICATE THE LIFT/SATURATION
FROM 270K-280K WILL CONTINUE ALONG/SOUTH OF THE MN RIVER VALLEY
THIS MORNING...SO EXPECT A PERIOD OF FREEZING DRIZZLE THERE. WILL
HIGHLIGHT THE THREAT FOR SOME MINOR GLAZING WITH A WINTER WEATHER
ADVISORY. THE MID LEVELS SATURATE THIS AFTERNOON...SO THE PRECIP
TYPE SHOULD TRANSITION TO SNOW. WARM AIR ADVECTION BLOSSOMS THIS
EVENING AS PRECIPITABLE WATER VALUES NEAR 0.6 INCHES. HAVE MOVED
THE START TIME OF THE WARNING A FEW HOURS EARLIER...AS IT APPEARS
THAT SNOW SHOULD EXPAND FROM SOUTH TO NORTH ACROSS THE CWA BETWEEN
00Z AND 06Z. AFTER 06Z THURSDAY..CONTINUE TO EXPECT THE POTENTIAL
FOR SLEET/FREEZING RAIN ACROSS THE SOUTHEASTERN CWA AS AN ELEVATED
WARM LAYER WORKS IN...AND 0-6KM LAYER MAX WET BULB TEMPS APPROACH
0 CELSIUS. ON THURSDAY...CONTINUE TO EXPECT A RESPITE FROM THE
MORE MODERATE INTENSITY SNOWFALL...UNTIL THURSDAY NIGHT AND
FRIDAY WHEN THE DYNAMICS ASSOCIATED WITH THE AFOREMENTIONED
MERGING LOWS ARRIVE...AND A TROWAL NOSES INTO THE AREA. THE NEARLY
VERTICALLY STACKED SYSTEM WOBBLES OVER IA/MO/IN INTO THE
WEEKEND...AND CONTRIBUTES TO CONTINUED MEASURABLE SNOWFALL THROUGH
SATURDAY.
THIS STORM SYSTEM IS REMINISCENT OF THE INFAMOUS HALLOWEEN BLIZZARD
OF 1991...AS WAS CONFIRMED BY THE GFS212 36 HOUR CIPS ANALOGS.
OVER 27 INCHES OF SNOW WAS OBSERVED AT THE MSP AIRPORT DURING THAT STORM...WHILE
FREEZING PRECIPITATION PLAGUED A GOOD PORTION OF IA INTO WESTERN
WI. THE EXTENDED DURATION OF THE ANTICIPATED SNOWFALL WITH THE IMPENDING
SYSTEM...ALONG WITH THE IMPRESSIVE MOISTURE PROGGED TO SURGE
NORTHWARD FROM THE GULF...CONTINUES TO SUPPORT ONE TO NEARLY TWO
FOOT SNOWFALL ACCUMULATIONS BY THE TIME THE HEAVIER SNOW WINDS
DOWN ON FRIDAY NIGHT...WITH RECORD VALUES CERTAINLY A POSSIBILITY. HAVE
MAINTAINED STORM TOTAL SNOWFALLS RANGING FROM 10 TO 20
INCHES...WITH THE LOWER ACCUMULATIONS EXPECTED ACROSS SERN MN INTO
WEST CENTRAL WI WHERE A DURATION OF MIXED PRECIP WILL LIKELY
RESULT IN LOWER TOTALS.
"THIS STORM SYSTEM IS REMINISCENT OF THE INFAMOUS HALLOWEEN BLIZZARD
OF 1991."
That was one dynamic system. Huge snow, freezing rain and rain within a 100 miles
000
FXUS63 KMPX 231025
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
425 AM CST WED DEC 23 2009
.DISCUSSION...
ATTENTION IS DRAWN TO A LARGE CLOSED LOW NEAR THE FOUR CORNERS
REGION ON EARLY MORNING WATER VAPOR IMAGERY. THIS FEATURE WILL DIG
SOUTH/EAST TODAY...EJECT NORTH ON THURSDAY...AND UNITE WITH A
SECONDARY LOW SINKING SOUTH FROM SASKATCHEWAN ON FRIDAY. ANTECEDENT
WARM AIR ADVECTION AND ISENTROPIC UPGLIDE AHEAD OF THE PRIMARY LOW
HAVE INITIATED AREAS OF FREEZING DRIZZLE AND A FEW FLURRIES
OVERNIGHT ACROSS SOUTHERN MN. NAM/GFS INDICATE THE LIFT/SATURATION
FROM 270K-280K WILL CONTINUE ALONG/SOUTH OF THE MN RIVER VALLEY
THIS MORNING...SO EXPECT A PERIOD OF FREEZING DRIZZLE THERE. WILL
HIGHLIGHT THE THREAT FOR SOME MINOR GLAZING WITH A WINTER WEATHER
ADVISORY. THE MID LEVELS SATURATE THIS AFTERNOON...SO THE PRECIP
TYPE SHOULD TRANSITION TO SNOW. WARM AIR ADVECTION BLOSSOMS THIS
EVENING AS PRECIPITABLE WATER VALUES NEAR 0.6 INCHES. HAVE MOVED
THE START TIME OF THE WARNING A FEW HOURS EARLIER...AS IT APPEARS
THAT SNOW SHOULD EXPAND FROM SOUTH TO NORTH ACROSS THE CWA BETWEEN
00Z AND 06Z. AFTER 06Z THURSDAY..CONTINUE TO EXPECT THE POTENTIAL
FOR SLEET/FREEZING RAIN ACROSS THE SOUTHEASTERN CWA AS AN ELEVATED
WARM LAYER WORKS IN...AND 0-6KM LAYER MAX WET BULB TEMPS APPROACH
0 CELSIUS. ON THURSDAY...CONTINUE TO EXPECT A RESPITE FROM THE
MORE MODERATE INTENSITY SNOWFALL...UNTIL THURSDAY NIGHT AND
FRIDAY WHEN THE DYNAMICS ASSOCIATED WITH THE AFOREMENTIONED
MERGING LOWS ARRIVE...AND A TROWAL NOSES INTO THE AREA. THE NEARLY
VERTICALLY STACKED SYSTEM WOBBLES OVER IA/MO/IN INTO THE
WEEKEND...AND CONTRIBUTES TO CONTINUED MEASURABLE SNOWFALL THROUGH
SATURDAY.
THIS STORM SYSTEM IS REMINISCENT OF THE INFAMOUS HALLOWEEN BLIZZARD
OF 1991...AS WAS CONFIRMED BY THE GFS212 36 HOUR CIPS ANALOGS.
OVER 27 INCHES OF SNOW WAS OBSERVED AT THE MSP AIRPORT DURING THAT STORM...WHILE
FREEZING PRECIPITATION PLAGUED A GOOD PORTION OF IA INTO WESTERN
WI. THE EXTENDED DURATION OF THE ANTICIPATED SNOWFALL WITH THE IMPENDING
SYSTEM...ALONG WITH THE IMPRESSIVE MOISTURE PROGGED TO SURGE
NORTHWARD FROM THE GULF...CONTINUES TO SUPPORT ONE TO NEARLY TWO
FOOT SNOWFALL ACCUMULATIONS BY THE TIME THE HEAVIER SNOW WINDS
DOWN ON FRIDAY NIGHT...WITH RECORD VALUES CERTAINLY A POSSIBILITY. HAVE
MAINTAINED STORM TOTAL SNOWFALLS RANGING FROM 10 TO 20
INCHES...WITH THE LOWER ACCUMULATIONS EXPECTED ACROSS SERN MN INTO
WEST CENTRAL WI WHERE A DURATION OF MIXED PRECIP WILL LIKELY
RESULT IN LOWER TOTALS.
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-
srainhoutx
- S2K Supporter
- Posts: 6919
- Age: 67
- Joined: Sun Jan 14, 2007 11:34 am
- Location: Haywood County, NC
- Contact:
Re: Christmas Eve/Day Storm System
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
433 AM EST WED DEC 23 2009
VALID 12Z WED DEC 23 2009 - 12Z SAT DEC 26 2009
...NRN/CENTRAL PLAINS AND MID/UPPER MS VLY...
A BLOCKBUSTER WINTER STORM IS GOING TO PUMMEL A GOOD PORTION OF
THE MIDWEST WED THROUGH FRI... EASILY PRODUCING BLIZZARD
CONDITIONS.
THE COMBINATION OF A SRN STREAM FEATURE OVER THE FOUR CORNERS
REGION AND A NRN STREAM CLOSED LOW OVER WRN CANADA WILL MEET AND
PHASE ACROSS THE PLAINS WED INTO THURS TO FORM A LARGE UPPER
VORTEX. THIS STACKED AREA OF LOW PRESSURE WILL MOVE LITTLE ON
FRI... AS A BLOCKING RIDGE UPSTREAM AND DOWNSTREAM OF THE LARGE
SCALE FEATURE PROHIBITS MUCH MOVEMENT.
THE ACTION WILL GET STARTED ON WED AS THE SRN STREAM SHORT WAVE
EJECTS INTO THE SRN PLAINS AND BEGINS TO INTERACT WITH A VERY
ACTIVE LL JET AND A PLETHORA OF AVAILABLE GULF OF MEXICO LL
MOISTURE. THE RESULTANT WILL BE A DEVELOPING AREA OF SURFACE LOW
PRESSURE NEAR THE ARKLATEX BY THURS MORNING AND THIS MOISTURE
OVERRUN THE ESTABLISHED THERMAL BOUNDARY PRESENT ACROSS THE
PLAINS/MS VLY INTO THE COLD SECTOR. A VORT JUST AHEAD OF THE MAIN
SRN STREAM SHORT WAVE AND ITS LEFT EXIT REGION OF A 250 MB JET
WILL ENHANCE THE VERTICAL LIFT TO ALLOW THIS MOISTURE TO FLOURISH.
THUS A BAND OF HVY SNOW AND POSSIBLE ICING WILL SET UP FROM SRN
WI/NRN IL BACK INTO SRN MN/IA/SERN SD AND ERN NE. AS THIS
OCCURS... THE SRN STREAM VORT WILL ALSO KICK UP AN INTENSE CHANGE
OVER TO DYNAMIC COOLING SNOW FROM WRN KS INTO THE OK/TX
PANHANDLES. TO THE NORTH... THE NRN STREAM CLOSED LOW AND INVERTED
SURFACE TROUGH WILL PROVIDE LARGE SCALE VERTICAL LIFT AND A FOCUS
FOR MDT TO HVY SNOWFALL FROM ERN SD THROUGH MUCH OF ND.
ON THURS INTO FRI OR D2... THE SURFACE LOW OVER THE ARKLATEX WILL
GO THROUGH COMPLETE SURFACE CYCLOGENESIS AND LIFT NORTH THROUGH
THE MID MS VLY BEFORE ANCHORING ACROSS IA. A TREMENDOUS
DEFORMATION ZONE IS EXPECTED TO SET UP AND ALLOW DYNAMIC
COOLING/FRONTOGENETIC FORCING TO PRODUCE BANDING SNOW. THE AXIS AT
THIS TIME FOR A FOOT OR MORE APPEARS LIKELY FROM NWRN IA NEWRD
THROUGH ERN MN/NWRN WI WITH SLIGHTLY LESS INTENSE SNOW SURROUNDING
THIS AXIS AND SPREADING DOWN SOUTH INTO ERN KS/WRN MO AND NERN OK.
THIS DOES NOT EVEN TAKE INTO CONSIDERATION OF THE STRONG CYCLONIC
FLOW AROUND THE LOW TO PRODUCE BLIZZARD LIKE CONDITIONS AND
BLOWING SNOW.
FINALLY ON FRI INTO SAT... THE STACKED AREA OF LOW PRESSURE WILL
SLOWLY BEGIN TO FILL AND DRIFT OFF TO THE NORTH AND EAST INTO SERN
MN/WRN WI. MOST OF THE DEEP LL MOISTURE WILL SPREAD INTO THE EAST
AND BECOME DETACHED FROM THE LARGE SCALE LOW. HOWEVER... HVY SNOW
WILL PERSIST ON THE BACKSIDE OF THE SYSTEM FROM THE DAKOTAS INTO
MN/IA. ALSO... THE SERLY FLOW/COMPONENT ON THE ERN SIDE OF THE
SYSTEM SHOULD KICK START INTENSE LAKE EFFECT SNOW OFF LAKES MI AND
SUPERIOR... IMPACTING PARTS OF NERN WI/UP OF MI AND NERN MN
RESPECTIVELY.
THIS SOUNDS LIKE EVERYTHING IS CLEAR CUT BUT MUCH SPREAD AND
UNCERTAINTY CONTINUES... ESPECIALLY WITH THE DETAILS IN THE FCST.
HPC FOLLOWED A BLEND OF THE 00Z GFS AND 12Z/22 ECMWF FOR CRITICAL
QPF AND THERMAL PROFILES FOR ALL PROBS ALL THREE DAYS.
...NRN MAINE...
HVY SNOW WILL PERSIST ONE MORE DAY ACROSS NRN ME AS ANOTHER HALF
FOOT IS POSSIBLE. A STRONG UPPER LOW WILL MOVE WEST TO EAST ACROSS
NEW ENGLAND ON WED AND A THERMAL BOUNDARY/INVERTED TROUGH AXIS
WILL REMAIN STATIONARY ACROSS ME. A TREMENDOUS INFLUX OF ATLANTIC
MOISTURE WILL SPREAD IN FROM THE NORTHEAST AND FOCUS ALONG THIS
AXIS. NEEDLESS TO SAY... THE MODEL GUIDANCE IS IN VERY GOOD
AGREEMENT AND HPC FOLLOWED A BLEND OF THE 00Z GFS AND 12Z/22
ECMWF.
...SRN/CENTRAL APPALACHIANS...
THE MODEL GUIDANCE IS FCSTING A LARGE DOME OF HIGH PRESSURE
BUILDING ACROSS ERN CANADA AND WEDGING DOWN THE EAST SIDE OF THE
APPALACHIANS ON THURS INTO FRI. THE COLD HIGH AND SHALLOW DENSE
AIR MASS WILL GRADUALLY BE INVADED BY THE COLD FRONT AND DEEP LL
MOISTURE FROM THE INTENSE STORM UPSTREAM OVER THE UPPER MIDWEST.
THIS MOISTURE WILL OVERRUN INTO THE COLD SECTOR POSSIBLY PRODUCING
ICING FROM WRN NC NORTHWARD INTO SWRN VA/ERN WV BEFORE THE UPPER
DYNAMICS/DEEP PLUME OF IMPRESSIVE PWS TRANSFER TO THE SOUTHEAST
COAST. HPC ISSUED A LOW PROB OF .25 INCH ICING FOR THE 24 HR FCST
PERIOD.
MUSHER
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
433 AM EST WED DEC 23 2009
VALID 12Z WED DEC 23 2009 - 12Z SAT DEC 26 2009
...NRN/CENTRAL PLAINS AND MID/UPPER MS VLY...
A BLOCKBUSTER WINTER STORM IS GOING TO PUMMEL A GOOD PORTION OF
THE MIDWEST WED THROUGH FRI... EASILY PRODUCING BLIZZARD
CONDITIONS.
THE COMBINATION OF A SRN STREAM FEATURE OVER THE FOUR CORNERS
REGION AND A NRN STREAM CLOSED LOW OVER WRN CANADA WILL MEET AND
PHASE ACROSS THE PLAINS WED INTO THURS TO FORM A LARGE UPPER
VORTEX. THIS STACKED AREA OF LOW PRESSURE WILL MOVE LITTLE ON
FRI... AS A BLOCKING RIDGE UPSTREAM AND DOWNSTREAM OF THE LARGE
SCALE FEATURE PROHIBITS MUCH MOVEMENT.
THE ACTION WILL GET STARTED ON WED AS THE SRN STREAM SHORT WAVE
EJECTS INTO THE SRN PLAINS AND BEGINS TO INTERACT WITH A VERY
ACTIVE LL JET AND A PLETHORA OF AVAILABLE GULF OF MEXICO LL
MOISTURE. THE RESULTANT WILL BE A DEVELOPING AREA OF SURFACE LOW
PRESSURE NEAR THE ARKLATEX BY THURS MORNING AND THIS MOISTURE
OVERRUN THE ESTABLISHED THERMAL BOUNDARY PRESENT ACROSS THE
PLAINS/MS VLY INTO THE COLD SECTOR. A VORT JUST AHEAD OF THE MAIN
SRN STREAM SHORT WAVE AND ITS LEFT EXIT REGION OF A 250 MB JET
WILL ENHANCE THE VERTICAL LIFT TO ALLOW THIS MOISTURE TO FLOURISH.
THUS A BAND OF HVY SNOW AND POSSIBLE ICING WILL SET UP FROM SRN
WI/NRN IL BACK INTO SRN MN/IA/SERN SD AND ERN NE. AS THIS
OCCURS... THE SRN STREAM VORT WILL ALSO KICK UP AN INTENSE CHANGE
OVER TO DYNAMIC COOLING SNOW FROM WRN KS INTO THE OK/TX
PANHANDLES. TO THE NORTH... THE NRN STREAM CLOSED LOW AND INVERTED
SURFACE TROUGH WILL PROVIDE LARGE SCALE VERTICAL LIFT AND A FOCUS
FOR MDT TO HVY SNOWFALL FROM ERN SD THROUGH MUCH OF ND.
ON THURS INTO FRI OR D2... THE SURFACE LOW OVER THE ARKLATEX WILL
GO THROUGH COMPLETE SURFACE CYCLOGENESIS AND LIFT NORTH THROUGH
THE MID MS VLY BEFORE ANCHORING ACROSS IA. A TREMENDOUS
DEFORMATION ZONE IS EXPECTED TO SET UP AND ALLOW DYNAMIC
COOLING/FRONTOGENETIC FORCING TO PRODUCE BANDING SNOW. THE AXIS AT
THIS TIME FOR A FOOT OR MORE APPEARS LIKELY FROM NWRN IA NEWRD
THROUGH ERN MN/NWRN WI WITH SLIGHTLY LESS INTENSE SNOW SURROUNDING
THIS AXIS AND SPREADING DOWN SOUTH INTO ERN KS/WRN MO AND NERN OK.
THIS DOES NOT EVEN TAKE INTO CONSIDERATION OF THE STRONG CYCLONIC
FLOW AROUND THE LOW TO PRODUCE BLIZZARD LIKE CONDITIONS AND
BLOWING SNOW.
FINALLY ON FRI INTO SAT... THE STACKED AREA OF LOW PRESSURE WILL
SLOWLY BEGIN TO FILL AND DRIFT OFF TO THE NORTH AND EAST INTO SERN
MN/WRN WI. MOST OF THE DEEP LL MOISTURE WILL SPREAD INTO THE EAST
AND BECOME DETACHED FROM THE LARGE SCALE LOW. HOWEVER... HVY SNOW
WILL PERSIST ON THE BACKSIDE OF THE SYSTEM FROM THE DAKOTAS INTO
MN/IA. ALSO... THE SERLY FLOW/COMPONENT ON THE ERN SIDE OF THE
SYSTEM SHOULD KICK START INTENSE LAKE EFFECT SNOW OFF LAKES MI AND
SUPERIOR... IMPACTING PARTS OF NERN WI/UP OF MI AND NERN MN
RESPECTIVELY.
THIS SOUNDS LIKE EVERYTHING IS CLEAR CUT BUT MUCH SPREAD AND
UNCERTAINTY CONTINUES... ESPECIALLY WITH THE DETAILS IN THE FCST.
HPC FOLLOWED A BLEND OF THE 00Z GFS AND 12Z/22 ECMWF FOR CRITICAL
QPF AND THERMAL PROFILES FOR ALL PROBS ALL THREE DAYS.
...NRN MAINE...
HVY SNOW WILL PERSIST ONE MORE DAY ACROSS NRN ME AS ANOTHER HALF
FOOT IS POSSIBLE. A STRONG UPPER LOW WILL MOVE WEST TO EAST ACROSS
NEW ENGLAND ON WED AND A THERMAL BOUNDARY/INVERTED TROUGH AXIS
WILL REMAIN STATIONARY ACROSS ME. A TREMENDOUS INFLUX OF ATLANTIC
MOISTURE WILL SPREAD IN FROM THE NORTHEAST AND FOCUS ALONG THIS
AXIS. NEEDLESS TO SAY... THE MODEL GUIDANCE IS IN VERY GOOD
AGREEMENT AND HPC FOLLOWED A BLEND OF THE 00Z GFS AND 12Z/22
ECMWF.
...SRN/CENTRAL APPALACHIANS...
THE MODEL GUIDANCE IS FCSTING A LARGE DOME OF HIGH PRESSURE
BUILDING ACROSS ERN CANADA AND WEDGING DOWN THE EAST SIDE OF THE
APPALACHIANS ON THURS INTO FRI. THE COLD HIGH AND SHALLOW DENSE
AIR MASS WILL GRADUALLY BE INVADED BY THE COLD FRONT AND DEEP LL
MOISTURE FROM THE INTENSE STORM UPSTREAM OVER THE UPPER MIDWEST.
THIS MOISTURE WILL OVERRUN INTO THE COLD SECTOR POSSIBLY PRODUCING
ICING FROM WRN NC NORTHWARD INTO SWRN VA/ERN WV BEFORE THE UPPER
DYNAMICS/DEEP PLUME OF IMPRESSIVE PWS TRANSFER TO THE SOUTHEAST
COAST. HPC ISSUED A LOW PROB OF .25 INCH ICING FOR THE 24 HR FCST
PERIOD.
MUSHER
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Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Ike/Harvey
Member: National Weather Association
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Facebook.com/WeatherInfinity
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Member: National Weather Association
Wx Infinity Forums
http://wxinfinity.com/index.php
Facebook.com/WeatherInfinity
Twitter @WeatherInfinity
Re: Christmas Eve/Day Storm System
5 inches so far. Heres a pic of the ruler in the snowpack.
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-
Dave
- Retired Staff
- Posts: 13442
- Age: 74
- Joined: Tue Aug 01, 2006 3:57 pm
- Location: Milan Indiana
- Contact:
I'm going to add this information to this thread if it needs to be moved be my guest, lol. Been awake since 230 am and not moving real fast now. Merry Christmas to all.
MESOSCALE DISCUSSION 2297
NWS STORM PREDICTION CENTER NORMAN OK
0531 AM CST FRI DEC 25 2009
AREAS AFFECTED...WRN VA...SERN WV...FAR NWRN NC
CONCERNING...FREEZING RAIN
VALID 251131Z - 251600Z
FREEZING RAIN WILL OVERSPREAD THE LEE OF THE CNTRL APPALACHIANS THIS
MORNING...BEFORE TRANSITIONING TO RAIN FROM SW TO NE MORE RAPIDLY
AFTER 16Z. SIGNIFICANT ICE ACCUMULATIONS APPEAR PROBABLE WITH 0.05
TO 0.15 IN/HR COMMON...LOCALLY UP TO 0.30 IN/HR.
STRONG LOW-LEVEL ISENTROPIC LIFT WITHIN A BROAD WARM CONVEYOR BELT E
OF VIGOROUS CYCLONE OVER THE MID-MS RIVER VALLEY HAS CONTRIBUTED TO
A SWATH OF LIGHT TO MODERATE PRECIPITATION ACROSS THE LOWER
APPALACHIANS/SOUTHEAST. DOWNSTREAM LOW-LEVEL HODOGRAPHS HAVE BECOME
INCREASINGLY LARGE /REF RECENT VWP DATA AT BLACKSBURG
VA/...INDICATIVE OF THE INTENSE WAA REGIME SHIFTING NEWD.
METAR/MESONET OBSERVATIONS CONFIRM TEMPERATURES HOLDING AOB FREEZING
ACROSS A PORTIONS OF THE HIGHER TERRAIN IN WRN NC BECOMING MORE
PERVASIVE ACROSS ERN WV INTO WRN/CNTRL VA...ROUGHLY NW OF A HKY TO
RIC LINE AS OF 11Z. MODEL FORECAST SOUNDINGS ARE CONSISTENT THAT A
PRONOUNCED WARM NOSE OF ABOVE FREEZING TEMPERATURES WILL RESULT IN
SIGNIFICANT FREEZING RAIN POTENTIAL AS SURFACE RIDGE AXIS REMAINS
CENTERED ALONG THE PIEDMONT/BLUE RIDGE MTNS. TEMPERATURES SHOULD
STRUGGLE TO WARM AOA FREEZING UNTIL AFTER AROUND 15-16Z AS THE
DEGREE OF WAA ALONG WITH LATENT HEAT/DOWNDRAFT WARMING EFFECTS AID
IN TRANSITION TO RAIN.
..GRAMS.. 12/25/2009
MESOSCALE DISCUSSION 2299
NWS STORM PREDICTION CENTER NORMAN OK
0650 AM CST FRI DEC 25 2009
AREAS AFFECTED...NWRN TO S-CNTRL PA...MD PANHANDLE
CONCERNING...FREEZING RAIN
VALID 251250Z - 251645Z
MIXED PRECIPITATION WILL BECOME INCREASINGLY WIDESPREAD THROUGH THE
MORNING ACROSS NWRN PA TO THE MD PANHANDLE. ALTHOUGH SOME
UNCERTAINTY PERSISTS OVER INITIAL PTYPE...CONSENSUS OF MODEL
FORECASTS SUGGESTS A PERIOD OF FREEZING RAIN WOULD BE LIKELY BY
15-18Z...AS PRECIPITATION RATES INCREASE TO AROUND 0.05-0.10 IN/HR.
BROAD WARM CONVEYOR BELT DOWNSTREAM OF INTENSE 985 MB CYCLONE OVER
THE MID-MO RIVER VALLEY HAS AIDED IN A SWATH OF LIGHT TO MODERATE
RAIN ACROSS THE UPPER OH VALLEY/LOWER GREAT LAKES. ALTHOUGH MODEL
FORECASTS DIFFER ON TIMING OF THIS PRECIPITATION SHIFTING
EWD...INCONSISTENCY APPEARS GREATER WITH THE HANDLING OF THE
LOWER-LEVEL THERMODYNAMIC PROFILE. BASED ON THE 12Z PITTSBURGH RAOB
WITH A WET-BULB TEMPERATURE MAX AROUND 7 DEG C NEAR 850 MB...06Z
NAM/GFS SOUNDINGS APPEAR TOO COOL RELATIVE TO 11Z RUC GUIDANCE.
ALTHOUGH WET-BULB EFFECTS MAY RESULT IN A SNOW OR SLEET MIX
INITIALLY /ESPECIALLY OVER CNTRL PA/...A PROGRESSIVELY ENLARGING
WARM NOSE OF TEMPERATURES AOA FREEZING JUST ABOVE THE SURFACE SHOULD
RESULT IN A TRANSITION TO PRIMARILY FREEZING RAIN BY THE 15-18Z TIME
FRAME. BASED ON UPSTREAM PRECIPITATION RATES...0.02 TO 0.05 IN/HR
WOULD BE LIKELY INITIALLY...INCREASING TO AROUND 0.10 IN/HR TOWARDS
18Z.
..GRAMS.. 12/25/2009
--------------------
MESOSCALE DISCUSSION 2300
NWS STORM PREDICTION CENTER NORMAN OK
0721 AM CST FRI DEC 25 2009
AREAS AFFECTED...MOST OF SD...CNTRL/ERN NEB
CONCERNING...BLIZZARD
VALID 251321Z - 251845Z
OCCASIONAL BLIZZARD CONDITIONS SHOULD BECOME MORE WIDESPREAD INTO
THIS AFTERNOON.
A 50-55 KT N/NWLY LLJ SAMPLED BY 12Z RAPID CITY SD/OMAHA NEB RAOBS
AND AREA VWP DATA...HAVE SUPPORTED RECENT SURFACE WIND GUSTS FROM 3O
TO 45 KT. OVERNIGHT MODEL FORECASTS ARE CONSISTENT THAT LOW-LEVEL
FLOW AOA 50 KT WILL BECOME INCREASINGLY EXPANSIVE AND LIKELY
STRENGTHEN AS 985 MB CYCLONE OVER SERN IA SHIFTS NWWD. MODERATE
LOW/MID-LEVEL ISENTROPIC LIFT WILL SUPPORT A CONTINUATION OF LIGHT
TO MODERATE SNOW THROUGH THIS AFTERNOON. THIS COMBINED WITH THE VERY
STRONG WINDS WILL YIELD MORE PERVASIVE BLIZZARD
CONDITIONS...PERSISTING FOR SEVERAL HOURS.
..GRAMS.. 12/25/2009
MESOSCALE DISCUSSION 2297
NWS STORM PREDICTION CENTER NORMAN OK
0531 AM CST FRI DEC 25 2009
AREAS AFFECTED...WRN VA...SERN WV...FAR NWRN NC
CONCERNING...FREEZING RAIN
VALID 251131Z - 251600Z
FREEZING RAIN WILL OVERSPREAD THE LEE OF THE CNTRL APPALACHIANS THIS
MORNING...BEFORE TRANSITIONING TO RAIN FROM SW TO NE MORE RAPIDLY
AFTER 16Z. SIGNIFICANT ICE ACCUMULATIONS APPEAR PROBABLE WITH 0.05
TO 0.15 IN/HR COMMON...LOCALLY UP TO 0.30 IN/HR.
STRONG LOW-LEVEL ISENTROPIC LIFT WITHIN A BROAD WARM CONVEYOR BELT E
OF VIGOROUS CYCLONE OVER THE MID-MS RIVER VALLEY HAS CONTRIBUTED TO
A SWATH OF LIGHT TO MODERATE PRECIPITATION ACROSS THE LOWER
APPALACHIANS/SOUTHEAST. DOWNSTREAM LOW-LEVEL HODOGRAPHS HAVE BECOME
INCREASINGLY LARGE /REF RECENT VWP DATA AT BLACKSBURG
VA/...INDICATIVE OF THE INTENSE WAA REGIME SHIFTING NEWD.
METAR/MESONET OBSERVATIONS CONFIRM TEMPERATURES HOLDING AOB FREEZING
ACROSS A PORTIONS OF THE HIGHER TERRAIN IN WRN NC BECOMING MORE
PERVASIVE ACROSS ERN WV INTO WRN/CNTRL VA...ROUGHLY NW OF A HKY TO
RIC LINE AS OF 11Z. MODEL FORECAST SOUNDINGS ARE CONSISTENT THAT A
PRONOUNCED WARM NOSE OF ABOVE FREEZING TEMPERATURES WILL RESULT IN
SIGNIFICANT FREEZING RAIN POTENTIAL AS SURFACE RIDGE AXIS REMAINS
CENTERED ALONG THE PIEDMONT/BLUE RIDGE MTNS. TEMPERATURES SHOULD
STRUGGLE TO WARM AOA FREEZING UNTIL AFTER AROUND 15-16Z AS THE
DEGREE OF WAA ALONG WITH LATENT HEAT/DOWNDRAFT WARMING EFFECTS AID
IN TRANSITION TO RAIN.
..GRAMS.. 12/25/2009
MESOSCALE DISCUSSION 2299
NWS STORM PREDICTION CENTER NORMAN OK
0650 AM CST FRI DEC 25 2009
AREAS AFFECTED...NWRN TO S-CNTRL PA...MD PANHANDLE
CONCERNING...FREEZING RAIN
VALID 251250Z - 251645Z
MIXED PRECIPITATION WILL BECOME INCREASINGLY WIDESPREAD THROUGH THE
MORNING ACROSS NWRN PA TO THE MD PANHANDLE. ALTHOUGH SOME
UNCERTAINTY PERSISTS OVER INITIAL PTYPE...CONSENSUS OF MODEL
FORECASTS SUGGESTS A PERIOD OF FREEZING RAIN WOULD BE LIKELY BY
15-18Z...AS PRECIPITATION RATES INCREASE TO AROUND 0.05-0.10 IN/HR.
BROAD WARM CONVEYOR BELT DOWNSTREAM OF INTENSE 985 MB CYCLONE OVER
THE MID-MO RIVER VALLEY HAS AIDED IN A SWATH OF LIGHT TO MODERATE
RAIN ACROSS THE UPPER OH VALLEY/LOWER GREAT LAKES. ALTHOUGH MODEL
FORECASTS DIFFER ON TIMING OF THIS PRECIPITATION SHIFTING
EWD...INCONSISTENCY APPEARS GREATER WITH THE HANDLING OF THE
LOWER-LEVEL THERMODYNAMIC PROFILE. BASED ON THE 12Z PITTSBURGH RAOB
WITH A WET-BULB TEMPERATURE MAX AROUND 7 DEG C NEAR 850 MB...06Z
NAM/GFS SOUNDINGS APPEAR TOO COOL RELATIVE TO 11Z RUC GUIDANCE.
ALTHOUGH WET-BULB EFFECTS MAY RESULT IN A SNOW OR SLEET MIX
INITIALLY /ESPECIALLY OVER CNTRL PA/...A PROGRESSIVELY ENLARGING
WARM NOSE OF TEMPERATURES AOA FREEZING JUST ABOVE THE SURFACE SHOULD
RESULT IN A TRANSITION TO PRIMARILY FREEZING RAIN BY THE 15-18Z TIME
FRAME. BASED ON UPSTREAM PRECIPITATION RATES...0.02 TO 0.05 IN/HR
WOULD BE LIKELY INITIALLY...INCREASING TO AROUND 0.10 IN/HR TOWARDS
18Z.
..GRAMS.. 12/25/2009
--------------------
MESOSCALE DISCUSSION 2300
NWS STORM PREDICTION CENTER NORMAN OK
0721 AM CST FRI DEC 25 2009
AREAS AFFECTED...MOST OF SD...CNTRL/ERN NEB
CONCERNING...BLIZZARD
VALID 251321Z - 251845Z
OCCASIONAL BLIZZARD CONDITIONS SHOULD BECOME MORE WIDESPREAD INTO
THIS AFTERNOON.
A 50-55 KT N/NWLY LLJ SAMPLED BY 12Z RAPID CITY SD/OMAHA NEB RAOBS
AND AREA VWP DATA...HAVE SUPPORTED RECENT SURFACE WIND GUSTS FROM 3O
TO 45 KT. OVERNIGHT MODEL FORECASTS ARE CONSISTENT THAT LOW-LEVEL
FLOW AOA 50 KT WILL BECOME INCREASINGLY EXPANSIVE AND LIKELY
STRENGTHEN AS 985 MB CYCLONE OVER SERN IA SHIFTS NWWD. MODERATE
LOW/MID-LEVEL ISENTROPIC LIFT WILL SUPPORT A CONTINUATION OF LIGHT
TO MODERATE SNOW THROUGH THIS AFTERNOON. THIS COMBINED WITH THE VERY
STRONG WINDS WILL YIELD MORE PERVASIVE BLIZZARD
CONDITIONS...PERSISTING FOR SEVERAL HOURS.
..GRAMS.. 12/25/2009
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-
Siberian Express
- S2K Supporter
- Posts: 99
- Joined: Tue Sep 27, 2005 9:13 pm
- Location: Minnesota, USA
Re:
RL3AO wrote:Complete bust. Only picked up 1" of snow overnight.
Well that's what alot of warm air will do. If it tracks 100, 200, or so miles to the east we get hammered.
Man, what a powerful storm. Looking at the IR GOES loop it's affectig weather across the whole of North America.
Found this statement within the 6:00 am AFD interesting....
"TO SHOW HOW RARE THIS TYPE OF SYSTEM IS...WITH THE PHASING AND LONG-LIVED OCCLUSION...THE CIPS ANALOG GUIDANCE THE PAST TWO DAYS HAS PREDOMINATELY REPORTED NO MATCHES FROM THE PAST 30 YEARS WITH THIS WEATHER PATTERN."
This is a rare one.
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