FXUS62 KJAX 290943
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
440 AM EST SUN NOV 29 2009
...FAIR WEATHER PATTERN TO CONTINUE THROUGH MONDAY...
...SIGNIFICANT STORM SYSTEM LIKELY NEXT WEEK...
.SHORT TERM...LATEST MSAS ANALYSIS SHOWS HIGH PRESSURE HAS SETTLED
OVER THE DEEP SOUTH WITH RIDGE AXIS ROUGHLY ALONG THE INTERSTATE
10 CORRIDOR. AS A RESULT...WINDS HAVE REALLY DECREASED FROM THE
LAST FE NIGHTS WITH MOST OB SITES REPORTING NEAR CALM CONDITIONS.
THIS WOULD NORMALLY RESULT IN OPTIMUM RADIATIONAL COOLING
CONDITIONS...BUT THICK CIRRUS CANOPY HAS PREVENTED THAT THUS FAR.
IN ADDITION...SURFACE MOISTURE LOOKS TO BE HIGHER THAN GUIDANCE
WAS SUGGESTING AND IT SEEMS UNLIKELY FOR MOST AREAS TO REALIZE
CURRENTLY ADVERTISED LOW TEMPS. EXCEPTION MAY BE THE EXTREME
WESTERN TIER WHERE CIRRUS COULD CLEAR OUT JUST PRIOR TO 12Z AND
ALLOW FOR A QUICK DROP IN TEMPS PRIOR TO SUNRISE.
TODAY AND MONDAY...HIGH PRESSURE WILL REMAIN THE DOMINANT FEATURE
OVER THE AREA...AND WITH UPPER LEVEL SHORTWAVE SHIFTING EAST OF THE
AREA THIS MORNING...EXPECT A MOSTLY SUNNY AFTERNOON WITH AFTERNOON
HIGHS CLIMBING ONCE AGAIN ABOVE CLIMO. TRENDS IN THE MODELS FOR
TONIGHT THE LAST FEW RUNS HAS BEEN TO DEVELOP A LOCALIZED HIGH
OVER THE PENINSULA ALLOWING FOR A BETTER RADIATIONAL NIGHT THAN
TONIGHT IN THE ABSENCE OF SIGNIFICANT CLOUD COVER. WILL GO AT OR
BELOW GUIDANCE FOR MONDAY MORNING BUT MODERATING AIRMASS SHOULD
STILL ONLY YIELD VALUES IN THE LOWER 40S. MONDAY ITSELF LOOKS TO
BE A TRANSITION DAY AS NORTHERN STREAM SHORTWAVE MOVES THROUGH THE
OHIO AND TENNESSEE VALLEY BRINGING A SURFACE FRONT ALONG WITH IT.
THIS ACTIVITY WILL REMAIN NORTH OF THE AREA FOR MOST OF THE DAY
RESULTING IN CONTINUED MILD TEMPS AND DRY CONDITIONS FOR THE FIRST
PART OF THE WORK WEEK.
MODELS THE LAST FEW DAYS HAVE REALLY BEEN TRENDING DRIER WITH THIS
INITIAL FRONT AS MAIN DYNAMICS AND ASSOCIATED LIFT SHIFT OFF THE
CAROLINA COAST LEAVING OUR AREA WITH A WEAKENING FRONT WITH
LIMITED MOISTURE. HAVE INCLUDED LOW END CHANCE POPS FOR THE
NORTHERN TIER FOR MONDAY EVENING BUT EVEN THAT MAY BE A STRETCH.
TUESDAY AND TUESDAY NIGHT...FRONTAL BOUNDARY LOOKS TO STALL OVER
SOUTHERN SECTIONS OF THE FORECAST AREA WITH EXCELLENT AGREEMENT
AMONG THE GFS...ECMWF AND THE NAM12. AT THE SAME TIME 4 CORNERS
LOW WILL BEGIN TO EJECT OUT WITH SOUTHERN STREAM BECOMING
INCREASINGLY ACTIVE AND SURFACE LOW DEVELOPMENT LOOKS LIKELY OVER
THE NORTHERN GULF OF MEXICO. THIS WILL ALLOW FOR A STRENGTHENING
WARM FRONTAL BOUNDARY AND 50 TO 60 KNOTS OF ISENTROPIC ASCENT
DEVELOPING JUST WEST OF THIS AREA. UNCERTAINTY CONTINUES AS TO HOW
MUCH OF THIS WILL IMPINGE UPON OUR WESTERN ZONES TUESDAY
NIGHT...BUT HAVE GONE CLOSE TO GUIDANCE FOR NOW WHICH TAKES LIKELY
POPS THROUGH NW GA ZONES. NO INSTABILITY NOTED WITH THE SYSTEM AT
THIS JUNCTION...BUT WITH SUCH A STRONG ISENTROPIC
PROFILE...INCLUSION OF THUNDER MAY BE REQUIRED WITH SUBSEQUENT
FORECASTS.
.LONG TERM...ONCE FRONT LIFTS NORTH OF THE AREA WED
MORNING...ATTENTION WILL TURN TOWARD SEVERE POTENTIAL. AS NOTED BY
PREVIOUS FORECASTER...STRONG DOWNWARD MOTION NOTED AHEAD OF THE
FRONT SO NOT EXPECTING ANY ISOLATED ACTIVITY PRIOR TO FRONTS
ARRIVAL. THIS IS NOT NECESSARILY A GOOD THING AS STRONG
INSOLATION COULD RESULT IN TEMPS REACHING THE LOWER 80S AND
PROVIDING MORE INSTABILITY THAN MODELS INDICATE. AT THIS
POINT...SOUNDINGS SHOW A FEW HUNDRED J/KG OF CAPE WITH THIS
SYSTEM...BUT DYNAMICS AND DIFFLUENCE ALOFT WILL LIKELY MORE THAN
OVERCOME THESE DEFICIENCIES. WIND CORE ON THE GFS NOW AT 65 KNOTS
AT 850 MB WITH THE ECMWF JUST A LITTLE LOWER. WILL DEFINITELY NEED
TO BEEF UP THE WIND DAMAGE THREAT IN THE GRIDS AND THE
HWO/GRAPHICASTS. ACTIVITY WILL QUICKLY DIMINISH FROM WEST TO EAST
WED EVENING WITH MODELS NOT SURPRISINGLY TRENDING COLDER NEXT WEEK
BEHIND THE STRONGER SYSTEM.
&&
.AVIATION...MOSTLY VFR CONDITIONS WILL CONTINUE THRU THE NEXT 24
HOURS. MAY BE OCCASIONAL MVFR RIGHT BEFORE SUNRISE WITH SOME LIGHT
FOG.
&&
.MARINE...LIGHT WINDS WILL BECOME SW AHEAD OF APPROACHING FRONT.
WINDS WILL BECOME NE BEHIND THE FRONT...THEN RAPIDLY VEER AHEAD
OF GULF LOW. WINDS WILL INCREASE AHEAD OF THE LOW AND TRAILING
FRONT...WITH GUSTS OVER GALE FORCE POSSIBLE BY MID-WEEK.
&&
.FIRE WEATHER...HAVE UPGRADED FIRE WX WATCH TO A RED FLAG WARNING
FOR THIS AFTERNOON. HAVE ALSO EXPANDED THE AREA A BIT FARTHER E.
MOISTURE LEVELS WILL INCREASE NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 44 74 46 / 0 0 10 30
SSI 69 51 72 53 / 0 0 0 20
JAX 73 45 75 53 / 0 0 0 20
SGJ 71 51 74 56 / 0 0 0 20
GNV 73 42 74 51 / 0 0 0 20
OCF 74 42 75 53 / 0 0 0 20
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM NOON THRU 5 PM TODAY FOR BAKER-COLUMBIA-
HAMILTON-SUWANNEE-UNION.
GA...NONE.
AM...NONE.
&&
$$
DEESE/CARROLL
