SPC Day 2 Thunderstorm Outlook Issued 1730Z 20040131

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ZCZC SPCSWODY2 ALL
ACUS02 KWNS 311730
SPC AC 311730

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CST SAT JAN 31 2004

VALID 011200Z - 021200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 SW
GLS CLL 55 SW TYR 10 SSE PRX 15 SSW TXK 35 WNW POE 15 SE 7R4.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM PSX AUS MWL FSI BVO
SZL 15 NW COU 10 S STL LIT MLU BTR 15 SSE BVE.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 60 SSW MIA 40 W ORL
25 SSE JAX.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN TX AND EXTREME WRN
LA...

...SYNOPSIS...
UPPER LOW OVER THE WRN GULF OF MEXICO IS EXPECTED TO EJECT ENEWD AND
WEAKEN IN CONFLUENT FLOW PATTERN ACROSS THE SERN ATLANTIC BASIN
THROUGH SUNDAY.  UPSTREAM MIDLEVEL SHORTWAVE TROUGH NOW CROSSING THE
DESERT SW WILL DIG SEWD INTO THE SRN ROCKIES TONIGHT...THEN EWD INTO
THE SRN PLAINS/TX SUNDAY NIGHT.  IN THE LOWER LEVELS...A WARM FRONT
WILL DEVELOP NWD INTO CNTRL FL TODAY AS A LOW OVER THE WRN GULF
BASIN MOVES EWD.  BY SUNDAY AFTERNOON...THE LOW SHOULD REDEVELOP
NEWD OVER THE SRN GULF STREAM WITH A WEAK COLD FRONT SURGING SEWD
THROUGH SRN FL AND THE CNTRL GULF.  TAIL END OF THIS FRONT WILL
REDEVELOP NWD INTO THE NWRN GULF AS PRESSURES FALL IN ADVANCE OF
UPSTREAM IMPULSE SUNDAY EVENING/NIGHT.

...ERN TX AND WRN LA...
BOUNDARY LAYER FLOW IS EXPECTED TO FAVOR ADVECTION OF CP AIR MASS
ACROSS THE ERN TWO-THIRDS OF THE GULF OF MX THROUGH THE NEXT 48
HOURS AS PERSISTENT SURFACE RIDGING PREVAILS AND FAIRLY HEALTHY
UPPER IMPULSE MOVES THROUGH THE GULF.  WAVELENGTH BETWEEN THIS
DISTURBANCE AND THE APPROACHING SWRN U.S. SYSTEM WILL NOT BE
SUFFICIENT FOR QUALITY MOISTURE RETURN ACROSS THE WRN GULF. 
INCREASING SLY LOW LEVEL FLOW WILL ENCOURAGE MID 50S TO LOWER 60S
SURFACE DEW POINTS TO SPREAD ONTO THE UPPER TX COASTAL PLAINS BY
SUNDAY AFTERNOON...BUT HIGHER INSTABILITY WILL REMAIN WELL OFFSHORE.
 ETA FORECAST SOUNDINGS APPEAR TO BE SUFFERING FROM THE SHALLOW
CONVECTIVE SCHEME AND ARE PROBABLY OVERDOING INLAND INSTABILITY
AXIS.

AS LARGE SCALE ASCENT ASSOCIATED WITH THE UPSTREAM SYSTEM SPREADS
ACROSS THE SRN PLAINS...TSTMS ARE EXPECTED TO DEVELOP OVER ERN TX
AND SERN OK AND SPREAD ENEWD.  THERE COULD BE A SMALL WINDOW OF
OPPORTUNITY FOR STRONGER MORE DISCRETE CELLS SUNDAY AFTERNOON ACROSS
ERN TX...BUT QUICK EVOLUTION INTO LINE SEGMENTS WILL BE FAVORED
DURING THE EVENING.  THE LINES SHOULD MOVE EWD INTO AR/LA AND WEAKEN
AS THEY MOVE BEYOND THE STRONGER INSTABILITY OVERNIGHT.  GIVEN THAT
STRONGER FORCING FOR ASCENT SPREADS NEWD TOWARD MO...LOW LEVEL FLOW
REGIME WILL BE SOMEWHAT DIVERGENT ACROSS SERN TX AND SWRN LA AND
UNCERTAINTY REMAINS ON LONGEVITY OF CONVECTIVE THREAT THIS FAR
SOUTH. GIVEN STORMS...VERTICAL SHEAR WILL BE SUFFICIENT FOR
PERSISTENT STORMS WITH LARGE HAIL OVER THE ENTIRE SLGT RISK.  IF
TSTMS CAN DEVELOP AND SURVIVE CLOSER TO THE COAST AND BECOME ROOTED
INTO THE BOUNDARY LAYER...THERE WILL BE SMALL PROBABILITIES OF
DAMAGING WINDS/ISOLD TORNADOES.  THE OVERALL NEGATIVE FOR WIDESPREAD
SEVERE WEATHER...THOUGH...WILL BE MINIMAL INSTABILITY.

...CNTRL/SRN FL...
GULF WAVE WILL LIKELY EJECT RAPIDLY NEWD AND WEAKEN TONIGHT AND
EARLY SUNDAY WITH WLY FLOW COMMENCING OVER MOST OF CNTRL/SRN FL BY
THE START OF THE PERIOD.  THUS...THE CONVECTIVE THREAT WILL DIMINISH
RAPIDLY.

..RACY.. 01/31/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.

$$