943
FXUS62 KJAX 240826 CCA
AFDJAX
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE JACKSONVILLE FL
355 AM EDT THU JUL 24 2008
SYNOPSIS
WATER VAPOR IMAGERY AND RUC 400 MB ANALYSIS SHOW A
WELL-DEFINED TROUGH EXTENDING FROM VA TO S CENTRAL GA TO THE WRN FL
PANHANDLE. MUCH DRIER AIR IS FILTERING IN ON THE BACK SIDE OF THIS
TROUGH AND ENTERING OUR GA ZONES. DEEPER MOISTURE RESIDES OVER THE
SRN ZONES WITH RECENT GPS-MET DATA AND RUC INDICATING PWATS OF 1.9
INCHES NEAR GAINESVILLE. AT SFC...TROUGHING IS N OF THE AREA FROM NC
TO S CENTRAL GA TO NEAR ERN AL. SYNOPTIC FLOW FROM SFC TO 10 KFT IS
BECOMING NW AS SEEN IN LATEST VWP AND MODEL OUTPUT GUIDANCE. SO FAR
RADAR IS QUIET BUT ANTICIPATE SOME CONVECTIVE ACTIVITY TO DEVELOP
LATER THIS MORNING OVER THE SW ZONES.
SHORT TERM
TODAY AND TONIGHT...MODELS ARE IN GOOD AGREEMENT THAT NW FLOW IN THE
7H-5H LAYER WILL BECOME MORE NLY AS THE TROUGHING OVER THE REGION
MOVES EWD AND HEIGHTS RISE. SFC TROUGHING N OF THE AREA WILL DROP
SWD AND DEEPER MOISTURE MOVES WELL S AND E WITH SKIES BECOMING
MOSTLY CLEAR TO PARTLY CLOUDY. A N TO S POP GRADIENT IS IN ORDER
TODAY WITH ONLY 20% FOR GA AND 30-40% OVER NE FL. SLIGHTLY HIGHER
POP IS ANTICIPATED FROM MARION COUNTY TO FLAGLER COUNTY IN AREA OF
DEEPEST MOISTURE. SHOWERS AND STORMS SHOULD FIRST BEGIN OVER THE
INTERIOR NE FL ZONES WHERE LOW LEVEL MOISTURE CONVERGENCE AND HIGHER
THETA-E AIR WILL RESIDE THROUGH MID MORNING. DUE TO DRYING ALOFT
AND TEMPS PUSHING THE LOWER 90S...ANY STORMS THAT GET GOING WILL BE
CAPABLE OF PRODUCING DAMAGING DOWNBURST WINDS AND MARGINALLY SEVERE
HAIL. MODIFIED CAPE FROM GFS AND NAM IS ABOUT 2300-2600 AND LI OF
-6. DIFFERENTIAL THETA VALUES ARE ESTIMATED AROUND 20-25 BUT HIGHER
IN SE GA. MAX TEMPS HIGHER TODAY THAN WED DUE TO LESS CLOUD COVER.
TONIGHT...ISOLD THUNDERSTORMS IN THE EVENING WITH PATCHY FOG
OCCURRING LATE.
FRIDAY...SFC TROUGHING OVER THE AREA AND A RELATIVELY DRY AIRMASS
WILL AGAIN YIELD LOWER POPS THAN PREVIOUS DAYS. PWATS OF 1.4 TO 1.7
INCHES ARE ANTICIPATED AND DRIEST AIR WILL BE FROM ABOUT 750-450 MB.
E COAST SEA BREEZE WILL HAVE AN EASIER TIME MOVING INLAND AND BEST
LOW LEVEL FORCING WILL BE OVER INLAND ZONES. WILL CONT WITH THE N TO
S POPS WITH 20% IN SE GA AND 30-40% OVER INLAND NE FL. TEMPS
EXPECTED TO PUSH INTO MID 90S OVER SE GA AND INLAND NE FL AND HEAT
INDICES JUST OVER 100 DEG AT TIMES. FRIDAY NIGHT...MAINLY EXPECT
ISOLATED THUNDERSTORM ACTIVITY OVER INLAND AREAS IN THE EVENING WITH
PATCHY FOG POSSIBLE AGAIN.
SATURDAY...SFC TROUGH IS NOT AS APPARENT AND RIDGING MAY WORK NWD
OVER FL. MOISTURE IS STILL SOMEWHAT LIMITED AND E COAST SEA BREEZE
SHOULD HAVE NO PROBLEM MOVING INLAND. WILL KEEP POPS LIMITED TO
ABOUT 20-30% FOR MOST AREAS. MAX TEMPS IN THE LOWER TO MID 90S
EXPECTED. ISOLATED EVENING SHOWERS AND STORMS ANTICIPATED SATURDAY
NIGHT.
LONG TERM
SUNDAY-WEDNESDAY. MODEL GUIDANCE HAS SHOWN INDICATIONS
OF ERN CONUS TROUGH TO DEEPEN A BIT DURING THIS TIME FRAME OR AT
LEAST KEEPING A WEAKNESS IN THE MID LEVEL RIDGE OVER THE FORECAST
AREA. GFS ENSEMBLE IN GENERAL AGREEMENT WITH THIS PATTERN AND KEEPS
500 MB TEMPS IN THE -6 TO -8 C DEG RANGE. AT SFC...RIDGE AXIS WILL
REMAIN S OF THE AREA AND WEAK TROUGHING WILL BE OVER THE SE STATES
WILL KEEP A SWLY FLOW OVER THE REGION. THIS PATTERN SHOULD FAVOR
TYPICAL AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS AND POPS IN
THE 30-50% RANGE AT THIS TIME. TEMPS APPEAR TO BE CLOSE TO
NORMAL...LOWS IN THE LOWER 70S AND HIGH AROUND 90.
AVIATION
PREVAILING VFR WITH MID/HIGH CLOUDS AT MOST TERMINALS
EARLY THIS MORNING. THE EXCEPTION WILL BE GNV WHERE THERE WILL BE
A SCATTERED DECK AT 400 FEET AND POSSIBLY TEMPO MVFR VSBY TIL 12Z.
WITH MUCH DRIER AIR ALOFT FILTERING IN TODAY BEHIND SHORT WAVE...
EXPECTING MUCH LESS COVERAGE OF STORMS AND PRIMARILY DURING THE
AFTERNOON. HOWEVER...WITH WITH LIGHT SYNOPTIC FLOW...WILL PROBABLY
HAVE SEABREEZES AND ASSOCIATED OUTFLOWS DEVELOP AND MOVE INLAND
DURING THE AFTERNOON WHICH MAY BRING IN ENOUGH MOISTURE TO HELP
PRODUCE A FEW STRONG STORMS WITH STRONG WIND GUST POTENTIAL.
HAVE GONE WITH PREVIOUS FORECAST OF CB AT JAX...CRG...SSI AFTER
18Z AND VCTS AT GNV AFTER 18Z. SOME OF THESE TERMINALS MAY NEED
SOME AMENDMENTS THIS AFTERNOON.
MARINE
A SURFACE TROUGH MOVES ACROSS THE WATERS THIS MORNING
AND THEN WASHES OUT. A RIDGE REMAINS ACROSS CENTRAL FLORIDA.
THIS PRODUCES A WEAK PRESSURE PATTERN WITH WINDS MAINLY SOUTH OR
SOUTHWEST 10 KNOTS OR LESS EXCEPT SOUTHEAST ALONG THE COAST
IN THE AFTERNOONS. SEAS 1 TO 3 FEET. SCATTERED AFTERNOON AND
EVENING STORMS. STRONG WIND GUST POTENTIAL WITH SOME OF THE
STORMS NEAR SHORE.
PRELIMINARY POINT TEMPS/POPS
AMG 94 70 96 71 / 20 20 20 10
SSI 90 75 89 76 / 20 20 10 10
JAX 91 71 93 72 / 30 20 20 10
SGJ 89 72 88 73 / 40 20 20 10
GNV 90 70 93 70 / 40 20 40 20
OCF 89 70 92 70 / 40 20 40 20
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
AM...NONE.
SHASHY/PETERSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page