Christmas Eve/Day Storm System

[brunota2003]

Well, it appears there is yet another major storm system in the works, this one will be right around Christmas, from what I'm reading. From the Jackson, KY NWS:

A LULL IS FORECAST TUESDAY INTO WEDNESDAY AS RIDGING SURFACE AND
ALOFT MOVES THROUGH.

THE FINAL SYSTEM AT THE END OF THE PERIOD INVOLVES THE GREATEST
UNCERTAINTY. THERE IS A FAIR AMOUNT OF CONFIDENCE THAT THERE WILL BE
ANOTHER MAJOR STORM SYSTEM AFFECTING THE SE CONUS INCLUDING OUR LOCAL
AREA. HOWEVER...THERE IS LOW CONFIDENCE IN THE TRACK AND TIMING OF
THE SYSTEM. WILL ALLOW FOR POSSIBILITY OF SNOW OR RAIN IN A BROAD
WINDOW OF POPS.

Definitely something to keep an eye on. My fiancee is supposed to be flying from Florida to Kentucky on the 27th until the 2nd, and I am supposed to be going home on R&R at the end of this month. She's never seen more than a couple inches of snow, and it has been several years since I've seen a deep snow (more than 2 or 3 inches), so I'm hoping they get dumped on for her, then hopefully we'll have another major storm come through while I am there.

[RNGR]

Shoot, I just want to see a snow storm here in Atlanta before I ship to Ft. Benning for Army basic training.

[Brent]

Shoot, I just want to see a snowstorm here in Atlanta before I ship to Ft. Benning for Army basic training.

There is a chance. I'm not getting my hopes up, but I like the setup. Rain/Snow is already mentioned for Wednesday Night/Thursday.

[brunota2003]

Here is the latest discussion from Jackson, KY regarding this storm...hope the white Christmas solution is the one that is right!

.LONG TERM.../MONDAY NIGHT THROUGH SATURDAY/

UPPER PATTERN IN THE LONG TERM WILL START OUT WITH BROAD NORTHWEST
FLOW ACROSS EAST KENTUCKY...HOWEVER BY WEDNESDAY...BRIEF RIDGING
BUILDS INTO THE REGION AS POTENT H5 SHORTWAVE DIGS ACROSS THE
SOUTHERN PLAINS AND AMPLIFIES. THIS SYSTEM DEVELOPS A STRONG SURFACE
LOW AND FOCUS SHIFTS TO ITS TRACK EJECTING OUT OF THE CENTRAL PLAINS
WEDNESDAY NIGHT AS MID LEVEL HEIGHTS ALSO BEGIN TO LOWER. AT THIS
POINT OPERATIONAL MODELS AGREE THAT THE TRACK WILL BE WEST OF THE
AREA...HOWEVER THERE HAS BEEN SERIOUS FLIP FLOPPING AS OF LATE. HPC
PREFERRED A MORE SOUTHERLY TRACK THAT WOULD ACTUALLY TAKE THE SYSTEM
SOUTH OF OUR BORDER AND WAS DEPICTED BY THE 00Z GFS ENSEMBLE MEAN.
HOWEVER...12Z GFS ENSEMBLE MEAN HAS JUMPED ON BOARD WITH A NORTH AND
WEST TRACK THAT TAKES IT INTO CENTRAL INDIANA. THIS IS IN LINE WITH
OPERATIONAL GFS/ECMWF/CANADIAN.

SINCE CONFIDENCE REMAINS LOW AT THIS POINT...LETS TALK ABOUT
POSSIBLE SCENARIOS. EITHER TRACK HAS POTENTIAL TO PROVIDE PROBLEMS
LATE NEXT WEEK...JUST IN TIME FOR CHRISTMAS. THE MORE NORTHERLY
TRACK WOULD KEEP THINGS MOSTLY OR ALL RAIN...AND WITH RECENT MELTING
SNOW...WE COULD RUN INTO SOME HYDRO PROBLEMS. RIGHT NOW QPF DOESNT
LOOK TO BE OVER AN INCH AND FEEL THIS WOULDNT BE A HUGE IMPACT.
ALTHOUGH...AS WAS OBSERVED WITH OUR LATEST STORM...THE HIGH END QPF
SCENARIOS SOMETIMES DO PLAY OUT.

OTHERWISE...THE SOUTHERN TRACK SCENARIO THAT IS STILL CLINGING TO
HOPE WOULD PRESENT A COOLER AND SNOWIER SOLUTION...AND WE COULD BE
TALKING ABOUT A VERY WHITE CHRISTMAS.

DID NOT CHANGE MUCH IN THE WAY OF TEMPERATURES AS CONFIDENCE IS
STILL LOW...HOWEVER IF ANY TREND WAS NOTICEABLE IT WAS WARMER TO
REFLECT GROWING CONFIDENCE IN THE NORTH AND WEST TRACK OF THE
SURFACE LOW. WHICHEVER SOLUTION GELS OVER THE NEXT COUPLE OF DAYS
WILL SEE A MORE NOTICEABLE TREND IN TEMPERATURES. FOR NOW STUCK WITH
THE MIDDLE GROUND UNTIL A SOLUTION GAINS CONFIDENCE. ALSO...KEPT
PRECIPITATION TYPE BROAD WITH RAIN OR SNOW POSSIBLE.

[Siberian Express]

Models appear, at the moment, to be hinting that this will be a major midwest event.

[RL3AO]

Euro brings it over NE Iowa (perfect track for me), while the GFS brings it over Chicago. Still a long way out, but its got my attention.

[Siberian Express]

Looks intense, with heavy wet snow and could even bring some severe wx storms in the south. Rather dynamic and strong.

[srainhoutx]

Web Briefing from Des Moines, IA NWS...

http://www.crh.noaa.gov/dmx/briefing/

[brunota2003]

Things just get more confusing and hectic as we inch closer towards Christmas weekend. My fiancee is supposed to fly up to Kentucky on Sunday to spend next week with my parents (and hopefully I'll get home for leave before she has to go.......we'll see how that one pans out).

Longggg Long Term AFD from Jackson, KY:

.LONG TERM.../WEDNESDAY NIGHT THROUGH MONDAY/

A COMPLEX UPPER LEVER PATTERN KICKS OFF THE LONG TERM PORTION OF THE
FORECAST AS TWO TROUGHS WILL BE DROPPING THROUGH THE ROCKIES WHILE
RIDGING IS SQUEEZED AND AMPLIFIED THROUGH THE OHIO VALLEY. RIGHT OFF
THE BAT THE GFS IS FASTER WITH THE SOUTHERN MOST TROUGH TO OUR WEST
ON WEDNESDAY NIGHT THAN THE ECMWF AND NAM. THIS DIFFERENCE IS EVENED
OUT BY THURSDAY EVENING AS THE TROUGH SPIRALS AND DEEPENS INTO A DEEP
CLOSED LOW NEAR MKC...THOUGH THE GFS HOLDS BACK MORE ENERGY AND
KEEPS IT THE SECOND TROUGH FURTHER TO THE WEST...SINKING IT THROUGH
THE ROCKIES. MEANWHILE IN THE EAST...STRONG RIDGING WILL MOVE EAST TO
THE OTHER SIDE OF THE APPALACHIANS. AT THIS POINT...ANY SEPARATION
BETWEEN THE TROUGHS BLURS AS ONE BIG CLOSED LOW ROLLS NORTH THROUGH
THE MIDDLE AND UPPER MISSISSIPPI VALLEY ON FRIDAY...ONLY SLOWLY
APPROACHING KENTUCKY. BY SATURDAY MORNING THE GFS RETURNS TO ITS
PROGRESSIVE WAYS AND MOVES THE LOW INTO THE GREAT LAKES WHILE THE
ECMWF LINGERS ITS LOW BEHIND THROUGH THE WEEKEND. THESE DIFFERENCES
FURTHER MAGNIFY ON SUNDAY WITH THE DEEP LOW FROM THE ECMWF STILL JUST
ENTERING THE GREAT LAKES WHILE THE GFS HAS ALREADY SPUN ITS OWN NORTH
INTO CENTRAL CANADA. HOWEVER...LINGERING LOWER HEIGHTS THROUGH THE
OHIO VALLEY IN THE GFS WILL MITIGATE SOME OF THE DISCREPANCIES FOR
SENSIBLE WEATHER. MONDAY WILL FEATURE FLAT RIDGING BUILDING ACROSS
THE PLAINS AND INTO THE TENNESSEE VALLEY FROM THE GFS WHILE THE ECMWF
IS STILL SLOWLY CLEARING OUT THE UPPER LOW AND TROUGH OVER THE
REGION. HAVE FOLLOWED THE ECMWF MOST CLOSELY THROUGH FRIDAY BEFORE
SPLITTINGS THE DIFFERENCE WITH THE GFS FOR THE WEEKEND INTO
MONDAY...ALLOWING FOR A BIT MORE PROGRESSIVE A SOLUTION LATER IN THE
PERIOD.

SENSIBLE WEATHER WILL FEATURE A POTENT LOW DEVELOPING AND RACING
NORTH ON THURSDAY...JUST TO OUR WEST...BEFORE QUICKLY FILLING AND
SLOWLY DRIFTING THROUGH THE UPPER MIDWEST...GREAT LAKES...AND
NORTHERN OHIO VALLEY THROUGH THE HOLIDAY WEEKEND. THIS WILL FINALLY
CLEAR OUT ON MONDAY AND ALLOW HIGH PRESSURE TO RETURN TO THE AREA.
THE DEEPENING OF THE SYSTEM WILL HELP TO KEEP ITS FRONTAL STRUCTURE
FROM MOVING INTO EAST KENTUCKY UNTIL LATER THURSDAY...MINIMIZING THE
THREAT OF RAIN UNTIL THURSDAY NIGHT. ONCE THE FRONTS MOVE THROUGH
THAT NIGHT AND INTO FRIDAY...THEY SHOULD MOVE QUICKLY ENOUGH SO THAT
QPF WILL BE LIMITED ACROSS EAST KENTUCKY. AS A RESULT...EVEN WITH THE
MELTING SNOW FROM WEDNESDAY AND THURSDAY...EXPECT THE RIVERS TO BE
ABLE TO CONTAIN THE MELT OFF AND RUN OFF FROM ADDITIONAL RAINFALL.
THURSDAY WILL ALSO BE NOTED FOR ITS GUSTY WINDS AS A TIGHT PRESSURE
GRADIENT WILL PASS OVER THE CWA DURING THE AFTERNOON AND EVENING
HOURS...BUT AT THIS POINT IT LOOKS TO BE A WEAKER SET UP THAN THE
HIGH WINDS WE SAW FROM A SIMILAR STRONG LOW PASSING TO OUR WEST A
COUPLE OF WEEKS AGO.

FOLLOWING A COUPLE OF DAYS OF 50 PLUS TEMPERATURES...COLDER AIR WILL
POUR BACK INTO THE STATE ON WEST WINDS FRIDAY AND SATURDAY. THIS
COLDER AIR WILL COMBINE WITH THE SOMEWHAT LIMITED WRAP AROUND
MOISTURE OF THE SYSTEM...AND VARIOUS UPPER LEVEL IMPULSE SPINNING
AROUND THE TROUGH...TO GENERATE A THREAT OF SNOW SHOWERS THROUGH THE
WEEKEND AND INTO MONDAY. THROUGHOUT THE WAKE OF THE SYSTEM/S COLD
FRONT THE WINDS WILL NEVER QUITE SWITCH AROUND TO A FAVORABLE
POSITION FOR UPSLOPE FLOW SO HAVE MINIMIZED THE ENHANCEMENT OVER OUR
EASTERN RIDGES LETTING THE BULK OF THE SNOW SHOWERS SLOWLY FILTER IN
FROM THE NORTHWEST AS THE STACKED SYSTEM FURTHER OPENS UP AND DRIFTS
BY TO THE NORTH. EVEN THE DEPTH OF THE COLD AIR IN THE WAKE OF THE
SYSTEM LOOKS PALTRY COMPARED TO THE EARLIER MODEL SUGGESTIONS. WITH
THE DISAGREEMENT IN THE MODELS FOR THE UPPER PATTERN ON MONDAY HAVE
CHOSEN TO MINIMIZE THE THREAT OF ANOTHER SOUTHERN SYSTEM DEVELOPING
AND AFFECTING EAST KENTUCKY LATE IN THE FORECAST...AS DEPICTED BY THE
12Z GFS.

FOR TEMPS...STAYED FAIRLY CLOSE TO HPC AND MOS GUIDANCE WITH ONLY
LIMITED TERRAIN BASED ADJUSTMENTS THROUGH THE PERIOD. POP-WISE...
WENT CATEGORICAL ON THURSDAY NIGHT INTO FRIDAY...SIMILAR TO THE MEX
GUIDANCE...THEN UNDERCUT THE MOS NUMBERS INTO MONDAY.

[Siberian Express]

so, now the NAM has it retrograding in Iowa??????

[RL3AO]

so, now the NAM has it retrograding in Iowa??????

Yeah. It stalls and occludes over Iowa.

[Siberian Express]

Well, something should shake it and bring it across LaCrosse...give us that 2 feet of snow! Models have had a hard time with with this system for the last week. GFS is running, so we'll have to see what it does, I didn't think blocking would be so strong. It's gonna be a slow mover.

[RL3AO]

Look at the difference between the 850mb 0C line between the NAM and GFS. NAM has it near Winona and the GFS has it near Madison.

[weatherguy425]

Maybe the NAM shows a stronger low (To small of a print to read pressures) therefore theres more WAA on the eastern side of the low and warmer hieghts

[RL3AO]

There both 992mb at 48 hours.

[weatherguy425]

hhmmm thats wierd, also wierd that models are opposite when it comes to the 0 line on the western side of the low...

[srainhoutx]

MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1236 AM EST WED DEC 23 2009

00Z/23 PRELIMINARY MODEL PREFERENCES


ANY INITIALIZATION ERRORS WITH THE NAM AND GFS DO NOT APPEAR TO
SIGNIFICANTLY IMPACT THEIR SOLUTIONS.

...MAJOR CYCLONE DEVELOPING OVER THE CENTRAL UNITED STATES...

THE GFS CLOSES OFF A COMPACT SURFACE CIRCULATION NEAR THE ARKLATEX
BY THE BEGINNING OF DAY 2...AHEAD OF THE NAM...GEM GLOBAL...AND
12Z/22 ECMWF...WHICH SLOWS THE NORTHWARD PROGRESSION OF THE LOW ON
THAT MODEL FOR THE REMAINDER OF THE PERIOD. THE NAM AND OLD ECMWF
FORCE A STRONGER TRIPLE POINT LOW OVER THE SOUTHEAST PIEDMONT
DURING THE SECOND HALF OF DAY 3. THE UKMET...AS PER ITS BIAS...IS
SLOWER THAT THE OTHER GUIDANCE WITH BOTH THE NORTHWARD PROGRESSION
OF THE LOW AND THE EASTWARD PROGRESSION OF THE ATTENDANT COLD
FRONT. THE GEM GLOBAL LEAPS EASTWARD TO THE MISSISSIPPI RIVER
WITH THE PRIMARY SURFACE LOW BY 00Z/25 FRIDAY...WELL AHEAD OF THE
OTHER MODELS. THE OLD ECMWF SEEMS TO BE IN THE MIDDLE OF THE
PACK...THOUGH IS DEEPER THAN ALL THE GUIDANCE WITH THE PEAK
INTENSITY AT 12Z/25 FRIDAY...AND AS SUCH MAY MAKE A GOOD
COMPROMISE SOLUTION AT THIS POINT

[brunota2003]

If you look at the NAM, it has a low to the SE, while the GFS doesnt. A low's winds are couterclockwise, so wouldnt the reason that the 0c line in the NAM is further west is because that secondary low would be pumping in warm air to the warm sector from the SE?

[srainhoutx]

Look at WV Imagery. A direct E flow from the Pacific through S TX and turning NE into SE TX...Big Storm with lots of dynamics. The NOGAPS and UKMET even suggest snow in N TX and flurries as far S as northern areas of SE TX.

http://www.srh.noaa.gov/tropical/satpix ... v_loop.php

[Ntxw]

This storm looks to turn out stronger with multiple outcomes even though it's only a few days away.