000
FXUS62 KMFL 151510 AAA
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1010 AM EST SUN FEB 15 2009

.UPDATE...UPDATED TO ALLOW BOTH, DENSE FOG ADVISORIES OVER AND GULF
WATERS/LAKE OKEECHOBEE TO EXPIRE. SFC OBS AND SATELLITE IMAGES
INDICATED IMPROVING CONDITIONS. HOWEVER, WILL STILL KEEP PATCHY FOG
OVER THE GULF OF MEX WATERS THROUGH REST OF THE MORNING AND EARLY
AFTERNOON. REST OF THE FORECAST PACKAGE STILL ON TRACK.

.......................PREVIOUS DISCUSSION......................

.AVIATION...
WIDESPREAD FOG CONTINUES ACROSS SOUTH FL WITH DENSE FOG IN MANY
AREAS. FOG WILL IMPACT ALL TERMINALS EARLY THIS MORNING BUT BURN
OFF A FEW HOURS AFTER SUNRISE. A FEW SHRA MAY IMPACT EAST COAST
TERMINALS AS SEA BREEZE MOVES INLAND MID DAY/THIS AFTERNOON. W
COAST SEA BREEZE COULD BRING FOG BACK INTO KAPF LATE THIS
AFTERNOON. SOME CHANCE FOR FOG OTHER TERMINALS AGAIN TONIGHT AHEAD
OF COLD FRONT BUT CLOUDS MAY LIMIT COVERAGE.

/STRASSBERG

&&

.PREV DISCUSSION... /ISSUED 526 AM EST SUN FEB 15 2009/

DISCUSSION...
ANOTHER FOGGY NIGHT IS CURRENTLY IN PROGRESS ACROSS SOUTH
FLORIDA...WITH STRATUS DECK THAT MOVED INLAND FROM THE
SOUTHEASTERN GULF OF MEXICO ON SATURDAY EVENING NOW BUILDING DOWN
AS WIDESPREAD DENSE FOG ACROSS MUCH OF THE AREA. ACROSS THE EAST
COAST...RESIDUAL MOISTURE FROM RAINFALL YESTERDAY AND SMOKE FROM
WILDFIRES IN THE EVERGLADES IS RESULTING IN DENSE FOG DEVELOPMENT
ACROSS THIS REGION AS WELL. EXPECT CONDITIONS TO IMPROVE FOR ALL
LOCATIONS...WITH THE EXCEPTION OF THE GULF WATERS AND IMMEDIATE
COASTAL LOCATIONS...BY MID-MORNING.

SHORT TERM MODELS AGREE THAT INFLUENCE OF STRONG MID/UPPER-LEVEL
RIDGE EXTENDING FROM CENTRAL AMERICA ACROSS THE CARIBBEAN SEA
WILL REMAIN SUPPRESSED FOR AT LEAST THE NEXT 24-36 HOURS...
ALLOWING FOR A SLIGHT IMPROVEMENT IN CHANCES FOR MUCH NEEDED
RAINFALL. IT NOW APPEARS THAT PRESSURE GRADIENT TODAY WILL REMAIN
WEAK ENOUGH TO ALLOW ATLANTIC COAST SEA BREEZE TO PENETRATE INLAND
THIS AFTERNOON...AND BASED ON COVERAGE OF SHOWER ACTIVITY
SATURDAY...DEEPER MOISTURE ANTICIPATED LATER TODAY...AND PRESENCE
OF WEAK SHEAR AXIS ALOFT APPROACHING REGION FROM THE CENTRAL
GULF...EXPECT AT LEAST SCATTERED SHOWERS TO DEVELOP OVER THE
INTERIOR BY LATE AFTERNOON. WEST-SOUTHWESTERLY STEERING FLOW WILL
ALLOW THIS ACTIVITY TO MOVE BACK TOWARD THE EAST COAST EARLY THIS
EVENING...AND WILL INCREASE POPS TO ACCOUNT FOR THIS.
MEANWHILE...AN UPPER-LEVEL VORT MAX DIGGING EAST-SOUTHEASTWARD
OVER THE TENNESSEE VALLEY WILL RESULT IN SURFACE CYCLOGENESIS OFF
THE ATLANTIC COAST OF NORTHEAST FLORIDA LATE TONIGHT...ALLOWING
COLD FRONT TO BEGIN MOVING SOUTHEASTWARD TOWARD THE AREA. EXPECT
FRONT TO EXTEND ROUGHLY ALONG THE APF-PBI CORRIDOR AROUND 12Z
MONDAY...WITH HIGHEST POPS IN THIS REGION. FRONT SHOULD MOVE
STEADILY SOUTHWARD OVER THE REGION BETWEEN 12-18Z MONDAY...WITH
SHOWER THREAT CONFINED TO THE NORTHEAST PORTION OF THE FORECAST
AREA AND ATLANTIC WATERS DURING TIME OF FRONTAL PASSAGE. EXPECT
BRISK NORTH TO NORTHEAST WINDS AND MODERATE COLD ADVECTION TO
OCCUR FOR REMAINDER OF THE DAY ON MONDAY AND MONDAY NIGHT...BEFORE
SURFACE HIGH SHIFTS EASTWARD OFF THE COAST OF THE MID-ATLANTIC ON
TUESDAY...RESULTING IN A RETURN TO EASTERLY FLOW.

RETURN FLOW PATTERN WILL CONTINUE IN THE EXTENDED PORTION OF THE
FORECAST...AS GLOBAL MODELS AGREE THAT A POWERFUL UPPER LOW
CURRENTLY SITUATED OFF THE COAST OF CALIFORNIA WILL SPREAD
EASTWARD ACROSS THE CENTRAL ROCKIES AND INDUCE SURFACE
CYCLOGENESIS OVER THE CENTRAL PLAINS BY MID-WEEK. ALTHOUGH
MOISTURE WILL BE INCREASING THROUGH THE PERIOD AS WINDS VEER TO
SOUTHEAST...UPPER-LEVEL RIDGE TO THE SOUTH OF THE AREA WILL BUILD
NORTHWARD IN ADVANCE OF THIS FEATURE...MAINTAINING GENERALLY DRY
CONDITIONS. AMPLIFICATION OF THE LONG WAVE PATTERN ACROSS NORTH
AMERICA IS STILL ANTICIPATED BY THE END OF THE WEEK...AS
PREVIOUSLY MENTIONED SYSTEM EJECTS NORTHEASTWARD AND A PAIR OF
UPPER LOWS DROP SOUTHEASTWARD OVER THE EASTERN HALF OF THE
COUNTRY. COLD FRONT ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO
ARRIVE IN SOUTH FLORIDA ON THURSDAY NIGHT OR FRIDAY MORNING...WITH
POTENTIAL FOR A FEW SHOWERS ALONG FRONT AND A MUCH COOLER/DRIER
AIRMASS FOR THE END OF THE WEEK.

MARINE...
DENSE FOG IS ONCE AGAIN THE MOST SIGNIFICANT MARINE CONCERN THIS
MORNING...WITH DENSE FOG ADVISORY IN EFFECT THROUGH 10 AM EST
FOR THE LOCAL GULF WATERS AND LAKE OKEECHOBEE. OTHERWISE...EXPECT
NORTH WINDS TO INCREASE TO AROUND 20 KNOTS OVER THE ATLANTIC/GULF
FOLLOWING PASSAGE OF COLD FRONT ON MONDAY...WITH 15-20 KNOTS
ANTICIPATED ON THE LAKE AND BISCAYNE BAY. WILL CONTINUE TO CAP
GULF STREAM SEAS AT 8 FEET...GIVEN SHORT DURATION OF HIGH WINDS
AND FLOW VEERING QUICKLY TO NORTHEAST. ANOTHER FRONTAL PASSAGE ON
THURSDAY NIGHT/FRIDAY MORNING WILL RESULT IN SIMILAR MARINE
CONDITIONS BY THE END OF THE WEEK.

FIRE WEATHER...
MINIMUM AFTERNOON RH VALUES MAY FALL TO AROUND 35-40 PERCENT
ACROSS THE NORTHWEST INTERIOR ON MONDAY AND TUESDAY AFTERNOONS.
HOWEVER...A MORE SIGNIFICANT AND WIDESPREAD FIRE WEATHER CONCERN
WILL COME ON FRIDAY AND SATURDAY AFTERNOONS...FOLLOWING THE
PASSAGE OF A STRONGER FRONT ON THURSDAY NIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  80  62  74  55 / 20 30 30 10
FORT LAUDERDALE  81  64  76  59 / 20 20 20 10
MIAMI            81  64  77  58 / 10 10 20 10
NAPLES           78  62  76  52 / 10 30 20 -

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR FLZ063-FLZ066-
     FLZ067-FLZ068-FLZ069-FLZ070-FLZ071-FLZ072-FLZ073-FLZ074-
     FLZ075-FLZ168-FLZ172-FLZ173-FLZ174.

AM...NONE.
GM...NONE.
&&

$$

LONG TERM...70/DD
SHORT TERM/AVIATION...65/GS