Moderator: S2k Moderators
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0358 AM CDT FRI MAR 14 2008
VALID 171200Z - 221200Z
...DISCUSSION...
THE PRIMARY FEATURE OF INTEREST DURING THE EXTENDED FORECAST PERIOD
WILL BE UPPER LOW WHICH WILL MOVE THROUGH THE SRN ROCKIES...SRN
PLAINS AND NRN MEXICO ON DAYS 4 AND 5 /MON AND TUE/. THE GFS
REMAINS MORE PROGRESSIVE IN THE EWD/NEWD MOVEMENT OF THIS LOW WHEN
COMPARED TO BOTH THE ECMWF AND UKMET. DESPITE THIS DIFFERENCE...IT
APPEARS THAT A MOIST AND UNSTABLE AIR MASS WILL BE COLOCATED WITH
STRONG VERTICAL SHEAR OVER A FAIRLY SIZABLE WARM SECTOR ON DAY 4
WITH AN ORGANIZED SEVERE WEATHER EPISODE POSSIBLE.
THIS SEVERE WEATHER THREAT SHOULD CONTINUE INTO AT LEAST DAY 5 OVER
ERN PARTS OF THE SRN PLAINS INTO LOWER MS VALLEY. THE POTENTIAL FOR
SEVERE WEATHER MAY CONTINUE INTO DAY 6 /WED/...THE EXTENT OF WHICH
REMAINS QUITE UNCERTAIN GIVEN THE MODEL DIFFERENCES IN THE HANDLING
OF THE UPPER TROUGH.
..MEAD.. 03/14/2008
.LONG TERM (SUNDAY NIGHT-FRIDAY)...
A SIGNIFICANT SEVERE WEATHER EVENT WILL BE POSSIBLE LATE MONDAY AFTERNOON AND MONDAY NIGHT ACROSS WEST CENTRAL TEXAS. DEEP UPPER TROUGH AND LOW ARE PROGGED TO MOVE SLOWLY EAST ACROSS THE DESERT
SOUTHWEST AND NORTHERN MEXICO MONDAY AND MONDAY NIGHT...BEFORE LIFTING OUT TO THE NORTHEAST INTO WEST TEXAS ON TUESDAY. LOW-LEVEL MOISTURE AND CLOUDS WILL INCREASE ON SUNDAY WITH THE STRENGTHENING RETURN FLOW FROM THE GULF. ON SUNDAY NIGHT...LOW-LEVEL JET AND THETA-E ADVECTION...ALONG WITH WITH A POSSIBLE LEAD WAVE EJECTING WELL OUT AHEAD OF THE MAIN UPPER SYSTEM...WILL BRING A CHANCE OF SCATTERED THUNDERSTORMS. A FEW STRONG/MARGINALLY SEVERE STORMS WILL
BE POSSIBLE SUNDAY NIGHT.
WITH THE APPOROACH OF THE VERY POTENT UPPER SYSTEM...DRYLINE WILL SETUP AND SHARPEN ACROSS WEST TEXAS ON MONDAY. AS THE SYSTEM BEGINS TO LIFT OUT...PACIFIC FRONT PROGGED TO OVERTAKE THE DRYLINE ANDPUSH EAST ACROSS WEST CENTRAL TEXAS MONDAY NIGHT/EARLY TUESDAY. WITH THE VERY STRONG DYNAMICS AND LIFT WITH THE SYSTEM...UNSTABLE AIRMASS AND VERY IMPRESSIVE VERTICAL SHEAR PROFILES...A SIGNIFICANT SEVERE WEATHER EVENT MAY OCCUR LATE MONDAY AFTERNOON INTO EARLY TUESDAY. AT THIS TIME APPEARS THE HIGHEST POPS FOR WEST CENTRAL TEXAS ARE WILL BE ON MONDAY NIGHT.
...SRN PLAINS...
A STRONG...SLY LLJ WILL BE MAINTAINED AHEAD OF UPPER TROUGH WHICH
WILL ENHANCE THE NWD TRANSPORT OF AN INCREASINGLY MOIST AIR MASS
WITH DEWPOINTS INCREASING THROUGH THE 60S AHEAD OF DRYLINE/PACIFIC COLD FRONT AND S OF RETREATING WARM FRONT. THIS MOISTURE COUPLED WITH STEEP MIDLEVEL LAPSE RATES IS EXPECTED TO CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS OVER PORTIONS OF OK SWD INTO CNTRL TX.
TSTMS /MAINLY ELEVATED/ ARE FORECAST TO EXPAND IN COVERAGE MONDAY MORNING N OF RETREATING WARM FRONT OVER OK EVENTUALLY INTO ERN KS AND MO ALONG NOSE OF LLJ. THE STEEP LAPSE RATES AND RELATIVELY STRONG CLOUD BEARING SHEAR SHOULD SUPPORT ORGANIZED/SUSTAINED UPDRAFTS WITH A THREAT OF LARGE HAIL. MORE ROBUST...SURFACE-BASED TSTM DEVELOPMENT IS EXPECTED BY AFTERNOON FROM VICINITY OF COLD FRONT AND DRYLINE/PACIFIC FRONT TRIPLE POINT OVER WRN OR CNTRL OK SWD INTO THE EDWARDS PLATEAU REGION. THE COMBINATION OF STRONG VERTICAL SHEAR AND MODERATE INSTABILITY INDICATE THE POTENTIAL FOR SUPERCELLS AND/OR BOWING LINE SEGMENTS CAPABLE OF TORNADOES... DAMAGING WINDS AND LARGE HAIL.
STORMS SHOULD GROW UPSCALE INTO A LINEAR CONVECTIVE SYSTEM MONDAY NIGHT INTO TUESDAY MORNING WITHIN A STRONGLY SHEARED KINEMATIC ENVIRONMENT. SUPERCELLS WILL REMAIN POSSIBLE WITHIN QLCS WITH A CONTINUED THREAT OF TORNADOES...DAMAGING WINDS AND HAIL.
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