AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
314 AM EDT FRI MAY 21 2010

.SYNOPSIS...AN UPPER LEVEL LOW IS SPINNING NEAR THE IA/MO BORDER
EARLY THIS MORNING WITH SHORT WAVE RIDGING TO THE E OVER THE ERN
STATES. A LOBE OF VORTICITY IS WORKING ITS WAY EWD ACROSS AL. THIS
FEATURE HAS HELPED MAINTAIN AN MCS OVER THE REGION...ALTHOUGH IT HAS
BEEN WEAKENING AS IT TRAVERSES THE CENTRAL PART OF THE STATE.
SURFACE ANALYSIS SHOWS AN OCCLUDED LOW OVER MO WITH A WARM FRONT
EXTENDING SEWD FROM IT INTO SERN AL AND SRN GA.

&&

.SHORT TERM...TODAY THROUGH SUN.
LOW TO MID LEVEL MEAN VECTOR WINDS WILL VEER AROUND TO THE S AND
THEN SW TODAY. IN ADDITION...WEAK QG FORCING IN THE FORM OF UPPER
LEVEL DIFFLUENCE AND DPVA WILL WORK WITH THE RETREATING SYNOPTIC
BOUNDARY TO PRODUCE SCATTERED THUNDERSTORMS TODAY. GENERALLY FOUND
THE MOS NUMBERS TO BE TOO LOW AND BASED THE FORECAST ON A
COMBINATION OF SEA BREEZE CLIMATOLOGY AND THE 12-KM WRF SOLUTION.
THE CONFIDENCE GRIDS GAVE US A GOOD START. OUR POPS RANGE FROM 50
OVER THE NRN TIER OF ZONES AND S CENTRAL GA TO 30 FURTHER SW. THE
LOWEST POPS OF 20 OR LESS WILL BE OVER THE COASTAL FL PANHANDLE.
CONVECTION IS EXPECTED TO DEVELOP NEWD THROUGH THE EVENING WITH
HIGHEST POPS OVER OUR GA ZONES. LOCAL CONFIDENCE GRIDS INDICATE
ROUGHLY A 20 PERCENT CONDITIONAL PROBABILITY FOR SEVERE STORMS OVER
SOME OF OUR GA ZONES FOR THIS AFTERNOON AND EVENING...ALTHOUGH THE
DAY-1 SLIGHT RISK AREA FROM SPC DOES NOT EXTEND THAT FAR S. TEMPS
WILL CONTINUE TO BE WELL ABOVE NORMAL THIS AFTERNOON WITH INLAND
AREAS PEAKING IN THE LOW 90S AND COASTAL AREAS IN THE UPPER 80S.
LOWS TONIGHT WILL ONLY FALL TO THE UPPER 60S INLAND TO LOWER 70S
COAST. FOR SAT... UPPER RIDGING WILL BUILD EWD ALONG THE GULF COAST
AS THE TROUGH LIFTS AWAY ACROSS THE MID ATLANTIC STATES. 1000-700
MB FLOW WILL VEER TO THE NW. STILL FEEL THAT MOS POPS ARE TOO LOW
AND WILL INCLUDE 20 POPS OVER OUR FL AND S CENTRAL GA ZONES. LOOK
FOR SIMILAR CONDITIONS ON SUN. AS THE RIDGE BUILDS OVERHEAD...TEMPS
WILL GET EVEN HOTTER WITH MOST INLAND AREAS REACHING THE MID 90S FOR
THE FIRST TIME THIS SEASON ON SUN.

.LONG TERM...SUN NIGHT THROUGH NEXT FRI.
THE PERIOD BEGINS WITH AN AMPLIFIED UPPER PATTERN OVER THE STATES
CHARACTERIZED WITH A DEEP TROUGH OUT WEST...A RIDGE AXIS EXTENDING
NORTH TOWARD THE GREAT LAKES FROM THE CENTRAL GULF COAST AND A LARGE
UPPER LOW MIGRATING SOUTH ALONG THE EASTERN SEABOARD THROUGH THE
EARLY PORTION OF THE UPCOMING WEEK. AT THE SURFACE...A RIDGE AXIS
EXTENDING SOUTHWEST ACROSS THE REGION NEAR THE LOCAL FORECAST AREA
WILL LEAD TO PREDOMINANTLY LIGHT EAST AND NORTHEAST FLOW. ALTHOUGH A
FEW SHOWERS/STORMS ASSOCIATED WITH THE SEA BREEZE MAY DEVELOP EACH
AFTERNOON EARLY NEXT WEEK...POPS WILL REMAIN QUITE LOW THROUGH THIS
FORECAST PERIOD. GFS/ECMWF/GEM ARE INDICATING A WEAK BACKDOOR FRONT
APPROACHING FROM THE NORTH THROUGH THE MID-WEEK PERIOD. HOWEVER...
DUE TO THE LACK OF CONFIDENCE THIS FAR OUT INTO THE EXTENDED WILL
KEEP POPS LOW AND CONTINUE TO MONITOR FURTHER MODEL RUNS.

&&

.MARINE...TODAY THROUGH TUE.
WINDS AND SEAS WILL REMAIN LOW OVER THE WATERS THROUGH THE FORECAST
PERIOD. PEAK SPEEDS WILL OCCUR NEAR THE COAST IN THE AFTERNOON SEA
BREEZE. THE WRF ALSO INDICATES A WEAK SURGE OVER THE ERN WATERS THE
NEXT COUPLE OF NIGHTS.

&&

.AVIATION...THROUGH 06Z SAT.
IFR/MVFR VSBYS AND CIGS DUE TO FOG WILL REMAIN IN THE FORECAST
THROUGH THE EARLY MORNING HOURS TODAY. VFR CONDITIONS WILL RETURN
THROUGH THE MID-MORNING HOURS. SCT-BKN CU FIELD AROUND 5 KFT WILL
BEGIN TO DEVELOP THROUGH THE LATE MORNING HOURS AND CONTINUE INTO
THE AFTERNOON. THE BEST CHANCE FOR SHOWERS AND STORMS WILL BE OVER
THE NORTHERN SITES (ABY/DHN) THROUGH THE AFTERNOON AND EVENING
HOURS. THESE STORMS WILL CONTINUE WELL INTO THE EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS WITH THE FRONTAL BOUNDARY TO THE NORTH.
WILL INSERT TEMPO GROUPS WITH REDUCED VSBYS/CIGS IN AND AROUND THESE
STORMS THAT DEVELOP DURING THIS PERIOD. ACTIVITY WILL TREND DOWN
THROUGH THE LATE NIGHT HOURS FRIDAY NIGHT.

&&

.FIRE WEATHER...RED FLAG CONDITIONS ARE NOT ANTICIPATED OVER THE
WEEKEND AND INTO THE UPCOMING WEEK AS PLENTY OF LOW-LEVEL MOISTURE
AND AFTERNOON SHOWERS AND STORMS REMAIN IN THE FORECAST. DISPERSIONS
WILL REMAIN HIGH DURING THE AFTERNOON PERIODS OVER THE NEXT COUPLE
OF DAYS WITH MIXING HEIGHTS AROUND 5 KFT.
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