Severe Thunderstorm Warning 105, NWS Mobile, AL

AREA FORECAST DISCUSSION...COR TO 3RD PERIOD TEMPS
NATIONAL WEATHER SERVICE MOBILE AL
317 PM CDT MON APR 21 1997

BROAD H5 LONGWAVE TROF PATTERN AMPLIFIES THRU 00Z WED AS SERIES OF
SIGNIFICANT MID LEVEL S/WAVES MOVE DOWN BACK SIDE OF TROF AND
STRENGTHEN LEE OF THE ROCKIES TO BE LOCATED OVER KS/OK AND LA/MS BY
00Z WED.  WEAKER MID LEVEL S/WAVE MEANWHILE EJECTS FROM LONGWAVE TROF
PATTERN AND MOVES SLOWLY ACROSS CWA TUESDAY AFTERNOON INTO TUESDAY
EVENING AND IS MILDLY REFLECTED TO H95 WITH SUFFICIENT LOW LEVEL
CONVERGENCE TO GENERATE SCATTERED TSRA.  DRY AIR ABOVE H7 REMAINS
ENTRENCHED OVER CWA WITH MOISTURE DEPTH INCREASING SLIGHTLY TO H8.
CONSIDERING THAT CAPES INCREASE TO NEAR 2000 BY THE EARLY
AFTERNOON...MAINLY NEAR THE COAST...POTENTIAL EXISTS FOR STRONG
DOWNDRAFTS AND HAIL...BUT WILL HOLD OFF FROM MENTIONING IN ZONES DUE
TO MITIGATING FACTOR OF MILD LOW LEVEL CONVERGENCE.  FOR TUESDAY
NIGHT...LEADING MID LEVEL S/WAVE OVER LA/MS MOVES NE TO WRN TN BY 12Z
WED WITH ASSOCIATED SFC LOW MOVING TO NE AL WITH COLD FRONT MOVING
THROUGH CWA EARLY WED MORNING.  CONSIDERING COOL H5 TEMPS AND
CONTINUED PRESENCE OF DRY AIR AT MIDLEVELS...EXPECT SQUALL LINE OF
TSRA TO MOVE THROUGH CWA SHORTLY AFTER MIDNIGHT AS LOW LEVEL
CONVERGENCE ASSOCIATED WITH LOW LEVEL JET MAXIMIZES.  SOME QUESTION
STILL REMAINS AS TO SEVERITY OF SQUALL LINE IN THAT LOW LEVEL JET
WILL BE A MODERATE 30 KNOTS WITH H5 TEMPS HAVING PREVIOUSLY WARMED TO
NEAR -12 AND CAPES DECREASING TO 1000-1500 SO WILL HOLD OFF ON
MENTION OF STRONG OR SEVERE STORMS IN ZONES...ALTHOUGH THIS WILL HAVE
TO REMAIN CLOSELY MONITORED.

WINDS OVER THE MARINE AREA WILL CONTINUE ON A SLOW INCREASE THROUGH
TONIGHT TO 15 TO 20 KNOTS AS SYSTEM APPROACHES AND SCA MAY BE
REQUIRED.  SCT TSRA DEVELOP ACROSS COASTAL WATERS TUESDAY AFTERNOON
AND CONTINUE INTO TUESDAY NIGHT WITH POTENTIAL FOR STRONG
DOWNDRAFTS...SO CWA MAY BE REQUIRED FOR THESE PERIODS AS WELL.

MOB 64/80/61/74 2463    PNS 66/79/64/77 2364
DTS 68/76/66/73 1344    EVR 60/81/59/68 2454 29

ALZ051>64-MSZ067-075-076-078-079-FLZ001>006-220600-

AREAL THUNDERSTORM OUTLOOK FOR
SOUTHWEST AL...NORTHWEST FL AND SOUTHEAST MS
NATIONAL WEATHER SERVICE MOBILE AL
1100 AM CDT MON APR 21 1997

A WARM AND INCREASINGLY MOIST AIR MASS WILL REMAIN ACROSS THE AREA
THROUGH THE EVENING HOURS.  PARTLY CLOUDY SKIES WILL ALLOW FOR THE
SUN TO WARM THE AIR NEAR THE SURFACE...WITH SURFACE TEMPERATURES
ALREADY NEAR 80...RESULTING IN A MODERATELY UNSTABLE ATMOSPHERE BY
THE EARLY AFTERNOON.  AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM
THE WEST AND ENTERS SOUTHEAST MISSISSIPPI BY THE EARLY
AFTERNOON...SCATTERED THUNDERSTORMS WILL DEVELOP OVER SOUTHEAST
MISSISSIPPI AND SPREAD INTO SOUTHWEST ALABAMA WEST OF INTERSTATE 65
BY MID AFTERNOON.  LOW LEVEL CONVERGENCE DUE TO ONSHORE FLOW AT 15 TO
20 MPH WILL BE MAXIMIZED DURING THE LUNCH HOUR AND EARLY AFTERNOON
EAST OF INTERSTATE 65 IN SOUTHWEST ALABAMA AND NORTHWEST
FLORIDA...RESULTING IN WIDELY SCATTERED SHOWERS AND THUNDERSTORMS.
AS THE UPPER LEVEL DISTURBANCE CONTINUES TO ADVANCE EASTWARD...THE
THUNDERSTORMS WILL BECOME MORE NUMEROUS EAST OF INTERSTATE 65 BY MID
AFTERNOON.  THE THUNDERSTORM ACTIVITY WILL DIMINISH WEST OF
INTERSTATE 65 DURING THE LATE AFTERNOON HOURS AS THE UPPER LEVEL
DISTURBANCE MOVES EAST OF INTERSTATE 65...WITH THUNDERSTORMS
DIMINISHING EAST OF INTERSTATE 65 LATER IN THE EVENING.

BY THE EARLY AFTERNOON HOURS...COOL TEMPERATURES AND DRY AIR AT MID
LEVELS IN THE ATMOSPHERE WILL BE CONDUCIVE TO DEVELOPING STRONG GUSTY
WINDS AND SMALL HAIL FROM THE THUNDERSTORMS...BUT THE THUNDERSTORMS
ARE EXPECTED TO REMAIN BELOW SEVERE LIMITS.

ACTIVATION OF STORM SPOTTERS IS NOT EXPECTED TO BE REQUIRED THROUGH
TONIGHT.