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Wednesday - LOOK OUT Alabama and the SOUTHEAST -

Posted: Sun Mar 16, 2003 1:14 am
by Stormsfury
I just saw some new information for Alabama, and the Southeast for Wednesday/Thursday ... and it looks quite frightening ...

Alabama, Georgia, and the Carolinas may be looking more and more in line for tornadoes if the ETA/ECMWF are correct in the wind profiles.

7 am EST WED Wind profiles
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850mb Wind Profiles
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300mb Wind profiles - look at how much divergence of winds occurs over AL/TN area.
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Also look at how much the winds veer with height.
Alabama/Georgia may actually see some large tornadoes if this wind parameters verify.

Posted: Sun Mar 16, 2003 8:49 am
by Stormsfury
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STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK
DAY 3 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWK48 KWNS.

VALID 181200-191200

THERE IS A SLIGHT RISK OF SEVERE STORMS FROM THE ERN PORTIONS OF
THE SRN PLAINS EWD ACROSS THE LOWER MS/TN RIVER VALLEYS.

...SYNOPSIS...
ALTHOUGH UPPER LOW IS FORECAST TO REMAIN QUASI-STATIONARY ACROSS
THE TX PANHANDLE...90-100 KT MID LEVEL SPEED MAX AND ASSOCIATED
SHORTWAVE TROUGH ARE FORECAST TO EJECT NEWD FROM SRN TX INTO THE
LOWER MS RIVER VALLEY. THE BROAD OCCLUDED UPPER TROUGH OVER THE SRN
HIGH PLAINS IS RESULTING IN HIGHER UNCERTAINTY IN EVOLUTION AND
TIMING FOR SEVERE WEATHER. HOWEVER...LATEST MODEL PACKAGES INDICATE
THE DAY 3 ENVIRONMENTAL CONDITIONS ARE MORE FAVORABLE FOR
SIGNIFICANT SEVERE WEATHER THAN THE CURRENT DAY 1 AND DAY 2
PERIODS.

...LOWER MS AND TN RIVER VALLEYS...
SURFACE LOW AND ASSOCIATED COLD FRONT ARE FORECAST TO BE LOCATED IN
ERN TX TUESDAY MORNING...WITH THE LOW/COLD FRONT EJECTING RAPIDLY
NEWD INTO ERN AR/MS TUESDAY NIGHT AS INTENSE MID/UPPER LEVEL JET
MAX AND DIFFLUENCE SPREAD ACROSS THE AREA. SIGNIFICANT
STRENGTHENING OF THE LOW LEVEL JET TO 50-60 KT COMBINED WITH
VEERING WINDS RESULTS IN FORECASTS OF 0-3 KM SRH VALUES FROM 300-
500 M**2/S**2 AND 1 KM SRH VALUES FROM 150-300 M**2/S**2. THE
SHORTWAVE TROUGH IN THE GULF IS FORECAST TO MOVE EAST OF FL AND
THIS WILL ALLOW RICHER GULF MOISTURE TO SURGE NWD ACROSS THE REGION
WITH DEWPOINTS LIKELY REACHING THE UPPER 60S. THIS SHOULD RESULT IN
MLCAPES OF AT LEAST 1500-2000 J/KG AND GIVEN THE STRONG SHEAR...
SUPERCELLS WITH LARGE HAIL AND DAMAGING WINDS APPEAR LIKELY.
TORNADOES WOULD ALSO BE EXPECTED...ESPECIALLY GIVEN THE FAVORABLE
INSTABILITY AND SHEAR...PLUS THE CLIMATOLOGY FOR NIGHTTIME/EARLY
MORNING TORNADOES ACROSS THIS PORTION OF THE COUNTRY DURING MARCH.


...NERN OK/SERN KS/SWRN MO...
LOW LEVEL FLOW IS FORECAST TO REMAIN SELY AND MAINTAIN DEWPOINTS IN
THE 50S. COLD TEMPERATURES ALOFT/ -18C TO -22C/ SHOULD RESULT IN
SUFFICIENT INSTABILITY FOR THUNDERSTORMS WITH SEVERE HAIL.

Posted: Sun Mar 16, 2003 9:16 am
by Stormsfury
Be also aware, training thunderstorms across portions of the Southeast as the overall storm system ejected only slowly that the potential for extensive flooding and tremendous rainfalls also exist.

60 hr QPF Potential from hrs 84-144.

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Posted: Sun Mar 16, 2003 11:23 am
by wx247
Good information. Thanks Stormsfury! It definitely looks to be a busy week with severe weather.

HPC's prelim discussion and take on upcoming threat

Posted: Sun Mar 16, 2003 12:34 pm
by Stormsfury
....ERN US...

AGAIN...QPF AND POSSIBLY STRONG CONVECTION ARE THE MAIN
CONCERNS. REPEATED MCS COMPLEXES MOVING INTO THE SRN
APLCNS MAINLY THU-FRI SUGGEST EXCESSIVE RA TOTALS. THE 2
DAY GFS/ECMWF QPFS OF 4-6" LIQUID IN THE SRN APLCNS LOOK
REASONABLE....THIS APPLIES TO THU-FRI.

NEW 06Z/16 GFS PLAYED DOWN A IMPULSE BRINGING .50-1" OF RA
INTO THE RNK FORECAST AREA FOR WED. THIS TREND SEEMS
REASONABLE AND WE EXPECT THE BIG RAINS TO HOLD OFF TILL
WED NIGHT...CONTINUING INTO FRI ....FROM GA/AL NEW INTO WRN
VA. INITIALLY...HEAVIEST QPF SHOULD OCCUR ALONG THE E
SLOPES OF THE APLCNS ...BUT HEAVIER RAINS WILL SPREAD MORE
INTO THE COASTAL PLAIN BY FRI.

NEW SYS COULD AFFECT THE SRN PLAINS/MS VLY BY NEXT
WEEKEND IN LINE WITH THE EXPECTED FASTER ECMWF SPEED OF
THE UPPER SYS EXITING THE SWRN STATES. MOST OF THE
EFFECT ON TEMPS/PCPN WILL BE S OF THE LATITUDE OF THE RED
RIVER NEXT SAT-SUN. SEE GRAPHICS.

Posted: Sun Mar 16, 2003 4:13 pm
by Stormsfury
12z GFS shifts the 5"+ bullseye a little bit eastward in South/North Carolina from the 6z Run.

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Posted: Mon Mar 17, 2003 10:02 am
by Stormsfury
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STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK
DAY 3 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWK48 KWNS.

VALID 191200-201200

A SLIGHT RISK OF SEVERE THUNDERSTORMS IS FORECAST OVER THE LOWER
OH/TN RIVER VALLEYS INTO THE SOUTHEASTERN U.S.


ETA AND AVN ARE IN AGREEMENT IN MAINTAINING A STRONG/VERTICALLY
STACKED LOW PRESSURE CENTER OVER OK/SRN KS DURING THE PERIOD...
WITH A PAIR OF STRONG VORT MAXIMA ROTATING AROUND THIS BROADER
CIRCULATION. LEADING SHORTWAVE TROUGH WILL LIFT NWWD THEN WWD OUT
OF THE OH RIVER VALLEY AND INTO THE CENTRAL PLAINS...WHILE NEXT
SYSTEM BEGINS ROTATING NEWD ACROSS THE LOWER MS RIVER VALLEY LATE
IN THE PERIOD.

...LOWER OH RIVER VALLEY/TN VALLEY/SOUTHEAST...
THOUGH LITTLE IN THE WAY OF LARGE SCALE SUPPORT WILL OVERRIDE A
BROAD AND MOISTENING WARM SECTOR...MID/UPPER LEVEL SWLY WINDS WILL
BE QUITE STRONG /H5 WINDS IN EXCESS OF 50 KT/ FROM THE OH RIVER
VALLEY ACROSS THE SOUTHEAST. IN ADDITION A LARGE AREA OF 1000-2000
J/KG MLCAPES CAN BE EXPECTED BY AFTERNOON. OUTFLOW BOUNDARIES AND
OTHER SUBTLE SURFACE FEATURES SHOULD SUPPORT CONVECTION DURING THE
PERIOD...WHICH WILL LIKELY BECOME ORGANIZED INTO LINES/SUPERCELLS
GIVEN STRENGTH OF DEEP LAYER SHEAR. ACTIVITY MAY INCREASE
OVERNIGHT ACROSS AL/GA AS NEXT SHORTWAVE TROUGH BEGINS EJECTING
NEWD TOWARDS THIS REGION.

...CENTRAL IL/MO/NRN AR/NERN OK/SERN KS...
FARTHER NW...VERY COLD MID LEVEL TEMPERATURES WILL PERSIST NEAR
UPPER LOW AS H5 TEMPS REMAIN AOB -20C. THOUGH MOISTURE AND HEATING
AT THE SURFACE WILL BE MORE LIMITED OVER THIS AREA...MARGINAL TO
MODERATE INSTABILITY MAY DEVELOP DURING THE AFTERNOON AND SUPPORT
A LOW PROBABILITY OF SEVERE THUNDERSTORMS.

..EVANS.. 03/17/03

Posted: Mon Mar 17, 2003 10:44 am
by Stormsfury
The progged rainfall totals (QPF) have backed off some. However, still potential for flooding rains later this week as over 2" QPF's are progged across the Carolinas.

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Posted: Mon Mar 17, 2003 9:06 pm
by breeze
The strong thunderstorms are supposed to move in here,
in southern mid-TN, tomorrow evening. Will be keeping
an eye out for the severe storms!

Posted: Mon Mar 17, 2003 9:26 pm
by Stormsfury
Um, look out North Carolina if this verifies....

7" of rain! ... YIKES :o :o :o

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