Strong 500 mb feature with divergent winds from Southwest above Southerly low level flow.
6Z GFS a shade faster with system, but shows instability and good wind dynamics.
Big Severe Wx Outbreak around 10/18/07 in Plains
Moderator: S2k Moderators
Forum rules
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.
-
Ed Mahmoud
Big Severe Wx Outbreak around 10/18/07 in Plains
Flow into Plains from Bay of Campeche, 850 mb winds 15 to 20 m/s (40 knots)
Strong 500 mb feature with divergent winds from Southwest above Southerly low level flow.
6Z GFS a shade faster with system, but shows instability and good wind dynamics.
Strong 500 mb feature with divergent winds from Southwest above Southerly low level flow.
6Z GFS a shade faster with system, but shows instability and good wind dynamics.
0 likes
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0404 AM CDT FRI OCT 12 2007
VALID 151200Z - 201200Z
...DISCUSSION...
SIGNIFICANT MODEL DIFFERENCES ARE NOTED BETWEEN THE GFS AND ECMWF
THIS FORECAST. WHILE BOTH MODELS BRING A FEATURE INTO THE PLAINS
DAY 6 /I.E. WEDNESDAY OCT. 17/...THE ORIGIN OF THE FEATURE WITHIN
THE TWO MODELS IS OF DIFFERENT. BY DAY 7...CORRELATION BETWEEN THE
TWO MODELS HAS DECREASED FURTHER...WITH THE ECMWF SHOWING A CLOSED
LOW OVER NERN NM AT 19/00Z...WHILE THE GFS SHOWS A CLOSED LOW OVER
IA. THUS...WILL NOT ATTEMPT TO DELINEATE ANY SEVERE AREA BEYOND DAY
6.
WILL MAINTAIN A THREAT AREA DAY 6 CENTERED ON KS/OK...BUT THIS IS A
RELATIVELY LOW-CONFIDENCE AREA DUE TO AFOREMENTIONED EVOLUTION
DIFFERENCES OF THE UPPER PATTERN BETWEEN THE MODELS. BOTH DO SHOW
THE PRESENCE OF A LEE LOW...AND SOME MOISTURE RETURN/DESTABILIZATION
INTO THE PLAINS. WITH FLOW ALOFT LIKELY SUPPORTIVE OF STORM
ORGANIZATION...POSSIBILITY OF SEVERE WEATHER EXISTS.
..GOSS.. 10/12/2007
NWS STORM PREDICTION CENTER NORMAN OK
0404 AM CDT FRI OCT 12 2007
VALID 151200Z - 201200Z
...DISCUSSION...
SIGNIFICANT MODEL DIFFERENCES ARE NOTED BETWEEN THE GFS AND ECMWF
THIS FORECAST. WHILE BOTH MODELS BRING A FEATURE INTO THE PLAINS
DAY 6 /I.E. WEDNESDAY OCT. 17/...THE ORIGIN OF THE FEATURE WITHIN
THE TWO MODELS IS OF DIFFERENT. BY DAY 7...CORRELATION BETWEEN THE
TWO MODELS HAS DECREASED FURTHER...WITH THE ECMWF SHOWING A CLOSED
LOW OVER NERN NM AT 19/00Z...WHILE THE GFS SHOWS A CLOSED LOW OVER
IA. THUS...WILL NOT ATTEMPT TO DELINEATE ANY SEVERE AREA BEYOND DAY
6.
WILL MAINTAIN A THREAT AREA DAY 6 CENTERED ON KS/OK...BUT THIS IS A
RELATIVELY LOW-CONFIDENCE AREA DUE TO AFOREMENTIONED EVOLUTION
DIFFERENCES OF THE UPPER PATTERN BETWEEN THE MODELS. BOTH DO SHOW
THE PRESENCE OF A LEE LOW...AND SOME MOISTURE RETURN/DESTABILIZATION
INTO THE PLAINS. WITH FLOW ALOFT LIKELY SUPPORTIVE OF STORM
ORGANIZATION...POSSIBILITY OF SEVERE WEATHER EXISTS.
..GOSS.. 10/12/2007
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
More Dr. Forbes, and less Dr. Lyons! Its October!
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
Not a sure bet, but what is a week away.
Relevant part snipped from AFD Tulsa
Relevant part snipped from AFD Tulsa
BEYOND TUESDAY...THE FORECAST BECOMES VERY DIFFICULT. THE MODELS
ARE SHOWING GREAT DIFFERENCES BETWEEN ONE ANOTHER AND FROM ONE
MODEL RUN TO THE NEXT. THERE IS SOME HINT OF AN INITIAL WAVE
MOVING ACROSS THE AREA WEDNESDAY SO WILL INTRODUCE SOME LOW POPS
AT THAT TIME. THE MORE SIGNIFICANT STORM SYSTEM LOOKS TO AFFECT
THE AREA SOMETIME IN THE LATER THURSDAY INTO FRIDAY
TIMEFRAME...AND POSSIBLY LINGER BEYOND THIS TIME IF THE ECMWF IS
TO BE BELIEVED. DEPENDING ON THE TRACK AND TIMING OF THIS
SYSTEM....A SIGNIFICANT WEATHER EVENT IS POSSIBLE INCLUDING ALL
POSSIBLE MODES OF SEVERE WEATHER AND EXCESSIVE RAINFALL. STAY
TUNED OVER THE NEXT SEVERAL DAYS.
0 likes
)-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
SPC discussion- outbreak probable, but details to difficult to specify area/time
...DISCUSSION...
SIGNIFICANT MODEL DIFFERENCES APPARENT 24 HOURS AGO CONTINUE THIS
FORECAST. THE CURRENT RUN OF THE ECMWF IS DEPICTING A MID-LEVEL
FLOW PATTERN VERY SIMILAR TO THE GFS RUN FROM 24 HOURS AGO...WHILE
DRASTICALLY DIFFERENT THAN ITS OWN FORECAST 24 HOURS PRIOR.
MEANWHILE...THE MOST RECENT 00Z RUN FROM THE GFS REVEALS A MID-LEVEL
FLOW PATTERN ENTIRELY DIFFERENT FROM THE RUN 24 HOURS AGO...DESPITE
THE FACT THAT THE RUN 24 HOURS AGO RESEMBLES THE LATEST ECMWF RUN.
OVERALL...THESE DRASTIC VARIATIONS IN MODEL SOLUTIONS WITH TIME
SUGGEST THAT PREDICTABILITY AT THE LARGE SCALE IS LOW AT THIS TIME.
THOUGH MODELS DO AGREE IN THE LARGE-SCALE MEAN THAT CYCLONIC FLOW
WILL PREVAIL ACROSS MOST OF THE CONUS THROUGH MUCH OF THE
PERIOD...DETERMINING WHICH DAYS THE SMALLER-SCALE TROUGHS WILL EJECT
ACROSS THE CENTRAL CONUS REMAINS DIFFICULT. THUS...WILL NOT INCLUDE
ANY SEVERE WEATHER AREAS THIS FORECAST...DESPITE THE FACT THAT
SEVERE WEATHER WILL LIKELY OCCUR SOMEWHERE ACROSS THE CENTRAL CONUS
TOWARD THE MIDDLE OF THE FORECAST PERIOD /INVOF DAYS 5-7...I.E. WED.
OCT. 17-FRI. OCT. 19/.
..GOSS.. 10/13/2007
0 likes
-
CrazyC83
- Professional-Met
- Posts: 33393
- Joined: Tue Mar 07, 2006 11:57 pm
- Location: Deep South, for the first time!
The SPC REALLY picked up on this one. Large threat area for Day 4, and hesitated on Day 5 before backing off at the last minute.
Looking at the models, CAPE should be around 2000, helicity around 400, wind shear should be significant and dewpoints should be in the 60s as far north as the northern Great Lakes, and in the 70s across much of the lower Mississippi Valley. The low is expected to deepen to about 980mb.
This has all the ingredients for a major tornado outbreak...as well as a serial derecho afterward or above/below the outbreak...
Looking at the models, CAPE should be around 2000, helicity around 400, wind shear should be significant and dewpoints should be in the 60s as far north as the northern Great Lakes, and in the 70s across much of the lower Mississippi Valley. The low is expected to deepen to about 980mb.
This has all the ingredients for a major tornado outbreak...as well as a serial derecho afterward or above/below the outbreak...
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
If the Euro from a week away was basically on the ball predicting this, I shall be impressed.
0 likes
-
HarlequinBoy
- Category 5
- Posts: 1400
- Age: 33
- Joined: Wed Nov 29, 2006 1:57 am
- Location: Memphis
-
Pebbles
- S2K Supporter
- Posts: 1994
- Joined: Tue Jul 08, 2003 1:42 pm
- Location: New Lenox, IL (SW of Chicago)
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
Wanting a lil more input here from some of our more exp members. I'm located just a few miles east of Joliet, IL (sw of Chicago). Are we looking at a T-Storm aka tornado threat or more of a Derecho event here on Thursday.
Only wanting input because if this is looking to be a pretty widespread outbreak going to have to ask the hubby to move boxes we had temp put in the entrance to our crawlspace while having a new ac/heater put in. It's the second half of October! Wasn't expecting tornado sirens to be a possiblity this late in the season.
Strange weather this year... lotsa crazy storms this summer and now only one tree on our block is dropping leaves... and only a couple at that!
Only wanting input because if this is looking to be a pretty widespread outbreak going to have to ask the hubby to move boxes we had temp put in the entrance to our crawlspace while having a new ac/heater put in. It's the second half of October! Wasn't expecting tornado sirens to be a possiblity this late in the season.
Strange weather this year... lotsa crazy storms this summer and now only one tree on our block is dropping leaves... and only a couple at that!
0 likes
-
CrazyC83
- Professional-Met
- Posts: 33393
- Joined: Tue Mar 07, 2006 11:57 pm
- Location: Deep South, for the first time!
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT TUE OCT 16 2007
VALID 171200Z - 181200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CENTRAL AND ERN
KS...WRN MO...CENTRAL AND ERN OK...NWRN AR...AND PARTS OF N TX...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL AND
SRN PLAINS AND INTO THE MID MS VALLEY REGION....
...SYNOPSIS...
LARGE/NEGATIVELY-TILTED TROUGH WILL PREVAIL OVER MUCH OF THE WRN 2/3
OF THE CONUS THIS PERIOD...WITH AN EMBEDDED SHORT-WAVE TROUGH
FORECAST TO CROSS THE CENTRAL U.S. AND EVOLVE INTO A CLOSED LOW OVER
THE MID MO VALLEY BY THE END OF THE PERIOD.
AT THE SURFACE...LOW IS FORECAST TO DEEPEN WHILE MOVING ENEWD FROM
WRN KS INTO THE MID MO VALLEY. A SURFACE DRYLINE EXTENDING S FROM
THIS LOW SHOULD SERVE AS A FOCUSING MECHANISM FOR AFTERNOON
STORMS...WHILE A COLD FRONT DEVELOPS/SHIFTS EWD ACROSS KS AND SEWD
ACROSS OK AND THE NWRN HALF OF TX THROUGH THE SECOND HALF OF THE
PERIOD.
...PARTS OF THE CENTRAL AND SRN PLAINS INTO THE MID MS VALLEY...
SIGNIFICANT SEVERE WEATHER EVENT -- INCLUDING THE POTENTIAL FOR
DAMAGING TORNADOES -- IS FORECAST ACROSS THE CENTRAL U.S. THIS
PERIOD -- CENTERED OVER PARTS OF KS AND OK.
THUNDERSTORMS WILL LIKELY BE ONGOING AT THE START OF THE PERIOD
ACROSS PARTS OF THE OUTLOOK AREA...AND MAY PERSIST INTO THE
AFTERNOON. THIS PRECIPITATION AND ASSOCIATED CLOUD COVER WILL
LIKELY LIMIT POTENTIAL FOR HEATING/DESTABILIZATION ACROSS PARTS OF
THE AREA. BY AFTERNOON HOWEVER...MOIST BOUNDARY LAYER COMBINED WITH
AREAS OF HEATING SHOULD RESULT IN POCKETS OF DESTABILIZATION...WITH
500 TO 1500 J/KG MIXED-LAYER CAPE LOCALLY EXPECTED BY AFTERNOON.
AS UPPER TROUGH APPROACHES FROM THE WEST...CONVECTIVE OUTFLOW OR
DIFFERENTIAL-HEATING BOUNDARIES AS WELL AS THE SHARPENING DRYLINE
MOVING TOWARD CENTRAL KS/ACROSS WRN OK SHOULD SERVE AS FOCI FOR NEW
STORM DEVELOPMENT. GIVEN ROUGHLY N-S DRYLINE AND DISTINCT WLY
COMPONENT TO THE MID-LEVEL FLOW -- PARTICULARLY ACROSS OK/N
TX...DISCRETE STORM DEVELOPMENT IS EXPECTED.
VERY STRONG WIND FIELD IS FORECAST...AS 50 TO 70 KT MID-LEVEL FLOW
SPREADS ACROSS THE WARM SECTOR ATOP STRONG SLY BOUNDARY-LAYER FLOW.
RESULTING DEEP-LAYER SHEAR SUGGESTS THAT INITIATING UPDRAFTS SHOULD
RAPIDLY ACQUIRE ROTATION...WITH SEVERAL SUSTAINED SUPERCELL STORMS
LIKELY. ALONG WITH THREAT FOR LARGE HAIL AND LOCALLY-DAMAGING
WINDS...LOW LCLS/MOIST BOUNDARY LAYER AND FAVORABLE LOW-LEVEL
VEERING/SHEAR SUGGEST THAT MULTIPLE TORNADOES WILL BE POSSIBLE. A
FEW OF THESE TORNADOES COULD BE STRONG AND RELATIVELY LONG-LIVED.
STORMS SHOULD CONTINUE/SPREAD EWD ACROSS MO/AR AND PERHAPS INTO THE
MID MS VALLEY REGION OVERNIGHT. GIVEN MOIST BOUNDARY LAYER AND
STRONG MIXING...NOCTURNAL STABILIZATION MAY BE LIMITED ENOUGH THAT A
TORNADO THREAT CONTINUES WELL INTO THE OVERNIGHT HOURS AS CONVECTION
SPREADS EWD.
..GOSS.. 10/16/2007
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0236 AM CDT TUE OCT 16 2007
VALID 181200Z - 191200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF IL AND
INDIANA...SERN WI...SRN LOWER MI...AND PARTS OF WRN KY....
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
CONUS BETWEEN THE MS VALLEY AND THE APPALACHIANS...
...SYNOPSIS...
MID-LEVEL TROUGH CROSSING THE CENTRAL U.S. IS FORECAST TO INTENSIFY
AND TAKE ON AN INCREASINGLY-NEGATIVE TILT WITH TIME.
MEANWHILE...ASSOCIATED SURFACE LOW WILL MOVE FROM IA INTO THE UPPER
GREAT LAKES REGION THROUGH THE PERIOD AS COLD FRONT SWEEPS EWD
ACROSS THE MIDWEST/OH VALLEY AND SEWD ACROSS THE GULF COAST STATES
THROUGH 19/12Z.
...ERN CONUS ROUGHLY FROM THE MS VALLEY EWD TO THE APPALACHIANS...
WIDESPREAD/POTENTIALLY-SIGNIFICANT SEVERE WEATHER EVENT IS EVIDENT
FOR DAY 3...AS LARGE UPPER TROUGH/LOW AND ASSOCIATED STRONG COLD
FRONT MOVE EWD ACROSS THE MS VALLEY. AHEAD OF THE FRONT...A VERY
LARGE WARM SECTOR IS ANTICIPATED...WHICH COMBINED WITH SOME DIURNAL
HEATING SHOULD RESULT IN MARGINAL TO LOCALLY-MODERATE INSTABILITY.
ATOP THE MOIST/DESTABILIZING BOUNDARY LAYER...VERY STRONG DEEP
TROPOSPHERIC WIND FIELD IS FORECAST TO OVERSPREAD THE FRONTAL ZONE
INTO THE WARM SECTOR...WITH 60 TO 80 SSWLY FLOW AT MID-LEVELS
FORECAST ATOP THE FRONT DURING THE AFTERNOON.
SCATTERED STORMS/STORM CLUSTERS SHOULD BE ONGOING ACROSS A LARGE
PORTION OF THE AREA DURING THE DAY...WITH AN INCREASE IN CONVECTIVE
INITIATION EXPECTED IN MULTIPLE BANDS CLUSTERS ALONG/AHEAD OF COLD
FRONT AS IT CROSSES THE MS VALLEY DURING THE AFTERNOON. WHILE FLOW
ROUGHLY PARALLEL TO THE FRONT DOES NOT APPEAR TO FAVOR
NUMEROUS/PRIMARILY DISCRETE STORMS...STORM MODE IS IMPOSSIBLE TO
DETERMINE AT THIS POINT. IT WOULD APPEAR THAT SOME COMBINATION OF
ISOLATED AND LINEAR STORMS WILL BE ONGOING DURING THE AFTERNOON --
LIKELY PRODUCING HAIL/DAMAGING WINDS...AS SHEAR WILL BE
STRONGLY-SUPPORTIVE OF LONG-LIVED/WELL-ORGANIZED STORMS. DEGREE OF
LOW-LEVEL SHEAR AND PRESENCE OF MOIST BOUNDARY LAYER ALSO SUPPORTS A
THREAT FOR TORNADOES.
ATTM...WILL INTRODUCE A MODERATE RISK ACROSS PARTS OF THE
MIDWEST...WHICH MAY BE EXPANDED TO INCLUDE AREAS AS FAR S AS THE
GULF COAST STATES IN LATER FORECASTS.
THREAT WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS...PERHAPS
SHIFTING ACROSS THE APPALACHIANS LATE.
..GOSS.. 10/16/2007
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT TUE OCT 16 2007
VALID 171200Z - 181200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CENTRAL AND ERN
KS...WRN MO...CENTRAL AND ERN OK...NWRN AR...AND PARTS OF N TX...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL AND
SRN PLAINS AND INTO THE MID MS VALLEY REGION....
...SYNOPSIS...
LARGE/NEGATIVELY-TILTED TROUGH WILL PREVAIL OVER MUCH OF THE WRN 2/3
OF THE CONUS THIS PERIOD...WITH AN EMBEDDED SHORT-WAVE TROUGH
FORECAST TO CROSS THE CENTRAL U.S. AND EVOLVE INTO A CLOSED LOW OVER
THE MID MO VALLEY BY THE END OF THE PERIOD.
AT THE SURFACE...LOW IS FORECAST TO DEEPEN WHILE MOVING ENEWD FROM
WRN KS INTO THE MID MO VALLEY. A SURFACE DRYLINE EXTENDING S FROM
THIS LOW SHOULD SERVE AS A FOCUSING MECHANISM FOR AFTERNOON
STORMS...WHILE A COLD FRONT DEVELOPS/SHIFTS EWD ACROSS KS AND SEWD
ACROSS OK AND THE NWRN HALF OF TX THROUGH THE SECOND HALF OF THE
PERIOD.
...PARTS OF THE CENTRAL AND SRN PLAINS INTO THE MID MS VALLEY...
SIGNIFICANT SEVERE WEATHER EVENT -- INCLUDING THE POTENTIAL FOR
DAMAGING TORNADOES -- IS FORECAST ACROSS THE CENTRAL U.S. THIS
PERIOD -- CENTERED OVER PARTS OF KS AND OK.
THUNDERSTORMS WILL LIKELY BE ONGOING AT THE START OF THE PERIOD
ACROSS PARTS OF THE OUTLOOK AREA...AND MAY PERSIST INTO THE
AFTERNOON. THIS PRECIPITATION AND ASSOCIATED CLOUD COVER WILL
LIKELY LIMIT POTENTIAL FOR HEATING/DESTABILIZATION ACROSS PARTS OF
THE AREA. BY AFTERNOON HOWEVER...MOIST BOUNDARY LAYER COMBINED WITH
AREAS OF HEATING SHOULD RESULT IN POCKETS OF DESTABILIZATION...WITH
500 TO 1500 J/KG MIXED-LAYER CAPE LOCALLY EXPECTED BY AFTERNOON.
AS UPPER TROUGH APPROACHES FROM THE WEST...CONVECTIVE OUTFLOW OR
DIFFERENTIAL-HEATING BOUNDARIES AS WELL AS THE SHARPENING DRYLINE
MOVING TOWARD CENTRAL KS/ACROSS WRN OK SHOULD SERVE AS FOCI FOR NEW
STORM DEVELOPMENT. GIVEN ROUGHLY N-S DRYLINE AND DISTINCT WLY
COMPONENT TO THE MID-LEVEL FLOW -- PARTICULARLY ACROSS OK/N
TX...DISCRETE STORM DEVELOPMENT IS EXPECTED.
VERY STRONG WIND FIELD IS FORECAST...AS 50 TO 70 KT MID-LEVEL FLOW
SPREADS ACROSS THE WARM SECTOR ATOP STRONG SLY BOUNDARY-LAYER FLOW.
RESULTING DEEP-LAYER SHEAR SUGGESTS THAT INITIATING UPDRAFTS SHOULD
RAPIDLY ACQUIRE ROTATION...WITH SEVERAL SUSTAINED SUPERCELL STORMS
LIKELY. ALONG WITH THREAT FOR LARGE HAIL AND LOCALLY-DAMAGING
WINDS...LOW LCLS/MOIST BOUNDARY LAYER AND FAVORABLE LOW-LEVEL
VEERING/SHEAR SUGGEST THAT MULTIPLE TORNADOES WILL BE POSSIBLE. A
FEW OF THESE TORNADOES COULD BE STRONG AND RELATIVELY LONG-LIVED.
STORMS SHOULD CONTINUE/SPREAD EWD ACROSS MO/AR AND PERHAPS INTO THE
MID MS VALLEY REGION OVERNIGHT. GIVEN MOIST BOUNDARY LAYER AND
STRONG MIXING...NOCTURNAL STABILIZATION MAY BE LIMITED ENOUGH THAT A
TORNADO THREAT CONTINUES WELL INTO THE OVERNIGHT HOURS AS CONVECTION
SPREADS EWD.
..GOSS.. 10/16/2007
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0236 AM CDT TUE OCT 16 2007
VALID 181200Z - 191200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF IL AND
INDIANA...SERN WI...SRN LOWER MI...AND PARTS OF WRN KY....
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
CONUS BETWEEN THE MS VALLEY AND THE APPALACHIANS...
...SYNOPSIS...
MID-LEVEL TROUGH CROSSING THE CENTRAL U.S. IS FORECAST TO INTENSIFY
AND TAKE ON AN INCREASINGLY-NEGATIVE TILT WITH TIME.
MEANWHILE...ASSOCIATED SURFACE LOW WILL MOVE FROM IA INTO THE UPPER
GREAT LAKES REGION THROUGH THE PERIOD AS COLD FRONT SWEEPS EWD
ACROSS THE MIDWEST/OH VALLEY AND SEWD ACROSS THE GULF COAST STATES
THROUGH 19/12Z.
...ERN CONUS ROUGHLY FROM THE MS VALLEY EWD TO THE APPALACHIANS...
WIDESPREAD/POTENTIALLY-SIGNIFICANT SEVERE WEATHER EVENT IS EVIDENT
FOR DAY 3...AS LARGE UPPER TROUGH/LOW AND ASSOCIATED STRONG COLD
FRONT MOVE EWD ACROSS THE MS VALLEY. AHEAD OF THE FRONT...A VERY
LARGE WARM SECTOR IS ANTICIPATED...WHICH COMBINED WITH SOME DIURNAL
HEATING SHOULD RESULT IN MARGINAL TO LOCALLY-MODERATE INSTABILITY.
ATOP THE MOIST/DESTABILIZING BOUNDARY LAYER...VERY STRONG DEEP
TROPOSPHERIC WIND FIELD IS FORECAST TO OVERSPREAD THE FRONTAL ZONE
INTO THE WARM SECTOR...WITH 60 TO 80 SSWLY FLOW AT MID-LEVELS
FORECAST ATOP THE FRONT DURING THE AFTERNOON.
SCATTERED STORMS/STORM CLUSTERS SHOULD BE ONGOING ACROSS A LARGE
PORTION OF THE AREA DURING THE DAY...WITH AN INCREASE IN CONVECTIVE
INITIATION EXPECTED IN MULTIPLE BANDS CLUSTERS ALONG/AHEAD OF COLD
FRONT AS IT CROSSES THE MS VALLEY DURING THE AFTERNOON. WHILE FLOW
ROUGHLY PARALLEL TO THE FRONT DOES NOT APPEAR TO FAVOR
NUMEROUS/PRIMARILY DISCRETE STORMS...STORM MODE IS IMPOSSIBLE TO
DETERMINE AT THIS POINT. IT WOULD APPEAR THAT SOME COMBINATION OF
ISOLATED AND LINEAR STORMS WILL BE ONGOING DURING THE AFTERNOON --
LIKELY PRODUCING HAIL/DAMAGING WINDS...AS SHEAR WILL BE
STRONGLY-SUPPORTIVE OF LONG-LIVED/WELL-ORGANIZED STORMS. DEGREE OF
LOW-LEVEL SHEAR AND PRESENCE OF MOIST BOUNDARY LAYER ALSO SUPPORTS A
THREAT FOR TORNADOES.
ATTM...WILL INTRODUCE A MODERATE RISK ACROSS PARTS OF THE
MIDWEST...WHICH MAY BE EXPANDED TO INCLUDE AREAS AS FAR S AS THE
GULF COAST STATES IN LATER FORECASTS.
THREAT WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS...PERHAPS
SHIFTING ACROSS THE APPALACHIANS LATE.
..GOSS.. 10/16/2007
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
WRF model shows impressive shear and decent instability forecasts for area ICT down to DFW tomorrow afternoon and evening.
Paris, TX
Paris, TX
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
Tulsa forecast sounding at 7 pm CDT has obscene wind shear lowest kilometer...
0 likes
-
CrazyC83
- Professional-Met
- Posts: 33393
- Joined: Tue Mar 07, 2006 11:57 pm
- Location: Deep South, for the first time!
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
Ed Mahmoud wrote:WRF model shows impressive shear and decent instability forecasts for area ICT down to DFW tomorrow afternoon and evening.
Paris, TX
The thread topic should be revised, as it is not just a Plains threat anymore but a three-day outbreak threat (October 17-19) across almost all of central and eastern North America.
What are the chances of this getting an early start today across and near the Panhandles?
0 likes
-
Ed Mahmoud
Re: Big Severe Wx Outbreak around 10/18/07 in Plains?
Crazy C83
per SPC
per SPC
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 NNW
SJT 15 ESE MAF 40 SSW LBB 30 ENE PVW 25 WNW LTS 30 WNW SPS 40 NNW
SJT.
0 likes
Return to “USA & Caribbean Weather”
Who is online
Users browsing this forum: MetroMike, snownado, TeamPlayersBlue and 37 guests