FXUS62 KMFL 230242
AFDMFL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
942 PM EST TUE DEC 22 2009
.UPDATE...SURFACE HIGH PRESSURE CONTINUES TO DOMINATE AND THE
EASTERLIES WILL INCREASE. THIS EVENINGS RAOB SOUNDING SHOWED A
SUBSIDENCE INVERSION AROUND 7000 FEET WITH JUST ENOUGH MOISTURE
BELOW TO SUPPORT ISOLATED SHOWERS. JUST A FEW SPRINKLES NOTED OVER
THE SOUTHERN ATLANTIC WATERS THIS EVENING BUT EXPECT OTHER SHOWERS
TO DEVELOP LATER TONIGHT. THE ONLY BIG CHANGE MADE WAS TO INCREASE
THE RISK OF RIP CURRENTS TO MODERATE ALONG THE ATLANTIC BEACHES
TONIGHT AND TO MENTION THE CHANCE THROUGH THURSDAY IN THE OUTLOOK.
&&
.PREV DISCUSSION... /ISSUED 634 PM EST TUE DEC 22 2009/
AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS
WITH LIGHT EASTERLY FLOW OVERNIGHT. THERE WILL LIKELY BE A
DRAINAGE FLOW DEVELOP BUT AM NOT CONVINCED IT WILL OVERCOME
STRENGTHENING EAST FLOW ALONG THE E COAST SO HAVE KEPT E WIND AT
THE E TERMINALS BUT AT SPEEDS LESS THAN 5KT. AT THE E TERMINALS ON
WEDNESDAY, GUSTS CAN BE EXPECTED AFT 14Z TO AROUND 20KT WITH NO
SEA BREEZE ALONG THE WEST COAST DUE TO THE STRONGER EASTERLY FLOW.
KOB
PREV DISCUSSION... /ISSUED 306 PM EST TUE DEC 22 2009/
DISCUSSION...SURFACE RIDGE OVER THE EASTERN SEA BOARD WILL SHIFT
INTO THE WESTERN ATLANTIC TONIGHT/WED LEADING TO A MORE
ESTABLISHED EASTERLY WIND FLOW. TRICKY FORECAST IN TERMS OF
TEMPERATURES TONIGHT. SHORTWAVE TROUGH IS OVER THE EASTERN GULF
AND THIS AXIS WILL CROSS THE AREA THIS EVENING...WITH THE
EXTENSIVE CLOUDINESS CLEARING OUT OF THE AREA FROM WEST TO EAST.
THE WIND DIRECTION FCST IS TRICKY TONIGHT. WEAK RIDGING DOWN THE
PENINSULA AND CLEARING SKIES LENDS TOWARDS A LAND BREEZE.
HOWEVER...GFS/NAM DO SHOW THE EAST FLOW ON THE INCREASE OVERNIGHT.
LIKE THE WRF-ARW DEPICTION OF WINDS/TEMPS WITH A LAND BREEZE EXCEPT
ALL BUT THE IMMEDIATE ATLANTIC COAST. SO THERE MAY BE QUITE A TEMP
GRADIENT FROM THE COAST TO THE WESTERN SUBURBS ALONG THE EAST
COAST. SIDED CLOSER TO THE WARMER WRF FOR KPBI/KFLL...AND CLOSE TO
GFS/NAM MOS OTHER LOCALES. LOWERED POPS...BUT DID KEEP A SLIGHT
CHANCE OF SHOWERS FOR THE EAST COAST OVERNIGHT AS THERE WILL BE
CONVERGENCE THERE BUT WITH QUESTIONABLE MOISTURE...HENCE THE
SLIGHT CHC POPS.
LOOKS LIKE RIDGE REMAINS IN CONTROL ON WED WITH AN EASTERLY FLOW
ALLOWING TEMPS TO MODERATE. THINGS CHANGE BY THURSDAY AS AN
INTENSE WINTER STORM TAKES SHAPE OVER THE NATIONS MID SECTION.
TROUGHING THERE PUSHING THE RIDGE FURTHER EAST ALLOWS FOR A RETURN
TO SOUTHERLY FLOW WITH INCREASING MOISTURE. THUS...RAIN CHANCES
WILL INCREASE ON THU...ESPECIALLY THU AFTERNOON/FRI EVENING. THE
LATEST GFS RUN SHOWS A LOW LEVEL TROUGH PIVOTING NORTH ACROSS
SOUTH FL THU AFTERNOON INTO FRI EVENING ALONG WITH PWATS
INCREASING TO NEAR 1.75 INCHES WITH THIS FEATURE. SO WILL HAVE TO
KEEP AN EYE ON THIS. HOWEVER...OTHER MODELS DO NOT SHOW THIS
FEATURE. HAVE GONE WITH HIGHEST POPS EAST COAST WHERE CONVERGENCE
WILL BE MAXIMIZED AND HAVE LOWERED POPS A BIT ALONG THE GULF
COAST.
CHRISTMAS LOOKS WARM WITH A PRE-FRONTAL TROUGH MOVING ACROSS THE
AREA AND THE MAIN FRONT NOT MOVING THROUGH UNTIL FRI NIGHT/EARLY
SATURDAY. AT THIS TIME...THE DYNAMICS ARE WELL NORTH OF THE AREA
AND INSTABILITY IS MARGINAL. SO KEPT CHANCE OF SHOWERS WITHOUT
THUNDER MENTION AT THIS TIME. THINGS IMPROVE OVER THE WEEKEND WITH
A COOL DOWN...THOUGH GFS IS SHOWING LESS OF A COOL OFF COMPARED TO
24 HR AGO.
MARINE...WINDS WILL INCREASE OUT OF THE EAST OVER THE NEXT FEW
DAYS LEADING TO INCREASING SEAS...ESPECIALLY IN THE GULF STREAM
WHERE SEAS OF UP TO 6 FT ARE EXPECTED WED-THU.
FIRE WEATHER...NO CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 64 76 66 79 / 10 10 10 30
FORT LAUDERDALE 68 76 68 79 / 10 10 10 30
MIAMI 64 77 68 79 / 10 10 10 30
NAPLES 54 78 60 82 / - - - 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
LONG TERM...18/GR
SHORT TERM/AVIATION...30/KOB
