000
FXUS64 KLIX 200949
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
349 AM CST THU NOV 20 2008
.DISCUSSION...
LATEST SURFACE ANALYSIS SHOWED A 1009MB LOW OVER EAST PORTIONS OF
THE GREAT LAKES REGION WITH A FRONTAL BOUNDARY EXTENDING SOUTHWEST
THROUGH THE OHIO VALLEY TO THE TEXAS PANHANDLE. A 1047MB HIGH WAS
NOTED OVER SOUTH CENTRAL CANADA AND MONTANA. WATER VAPOR IMAGERY
SHOWED SEVERAL DISTURBANCES FROM THE GREAT LAKES TO THE NORTHERN
PLAINS. SHORT RANGE MODELS HAVE SOMEWHAT PEGGED THE SHALLOWNESS OF
THIS AIRMASS OVER THE NORTH AND CENTRAL PLAINS THIS MORNING. GFS
AND NAM MODEL SOUNDING SHOW THE COLD AIR UNDERCUTTING THE WEST TO
NORTHWEST FLOW OVER THE EAST CONUS THROUGH THE WEEKEND. THE FRONT
SHOULD PUSH THE FORECAST AREA THIS EVENING THROUGH EARLY FRIDAY
MORNING. HAVE INCREASED CLOUD COVER GRID TONIGHT WITH THE
INITIALLY WITH WEST TO NORTHWEST FLOW OVER THE COLD AIR...BUT
DURATION OF CLOUDS SHOULD REMAIN BELOW 9 HOURS. BOUNDARY LAYER WINDS
AFTER THE FRONTAL PASSAGE WILL PUSH THE UP AGAINST WIND ADVISORY
CRITERIA SOUTH OF TIDAL LAKES FRIDAY...BUT SHOULD RELAX A LITTLE
AS THE HIGH SETS UP OVER THE TENNESSEE VALLEY BY FRIDAY NIGHT. THE
THICKNESS LAYERS ARE EXPECTED TO DECREASE...BUT NOT AS MUCH AS
LAST WEEK. WITH HIGH OVER TENNESSEE VALLEY...EAST FLOW MAY NOT GO
COMPLETELY GO CALM FOR INLAND AREA FRIDAY NIGHT. ERGO...WILL NOT
GO AS LOW NAM AND NGM NUMBERS OF BELOW 30F FOR FRIDAY NIGHT.
HOWEVER...A FREEZE IS POSSIBLE AGAIN FOR THE MISSISSIPPI
COAST...SOUTH MISSISSIPPI AND EAST CENTRAL LOUISIANA NORTH OF LAKE
PONTCHARTRAIN...BTR AREA WILL BE CLOSE AGAIN. GFS AND ECMWF ARE IN
AGREEMENT WITH A SHARP TROUGH DEVELOPING OVER UPPER AND MID
MISSISSIPPI VALLEY MONDAY AND AN AXIS ROTATING SOUTHEAST THROUGH
GULF COAST REGION MONDAY NIGHT. INSTABILITY REMAINS
MARGINALLY...SO WILL KEEP A SLIGHT CHANCE FOR THUNDERSTORMS AND A
CHANCE FOR SHOWERS MONDAY AND MONDAY. ANOTHER SYSTEM MAY BRING A
CHANCE OF RAIN ACROSS THE AREA AFTER THANKSGIVING.
&&
.AVIATION...
PATCHY FOG ACROSS THE AREA MAY LEAD TO BRIEF MVFR/IFR VISIBILITIES
THIS MORNING. VRBL WINDS WILL GRADUALLY BECOME WESTERLY AND THEN
N/NW TODAY AND THEN THIS EVENING AS A COLD FRONT SWEEPS THROUGH THE
REGION. WINDS BEHIND THE BOUNDARY WILL INCREASE TO OVER 10 KTS WITH
GUSTS APPROACHING 20 KTS...ESP AT MSY. EXPECT INCREASING LOW TO MID
LEVEL CLOUDS AT TERMINALS BEHIND THE FRONT. VFR CONDITIONS WILL
DOMINATE THROUGH THE PERIOD.
MEFFER
&&
.MARINE...
SURFACE HIGH PRESSURE OVER THE ENTIRE GULF OF MEXICO WILL KEEP WINDS
LIGHT THROUGH MUCH OF THE DAY AND SEAS WILL REMAIN RELATIVELY CALM.
A COLD FRONT IS EXPECTED TO PUSH THROUGH THE COASTAL WATERS TONIGHT
BRINGING INCREASING WINDS. EXPECT WINDS 15 TO 25 KTS WITH HIGHER
GUSTS...ESPECIALLY WELL OFF SHORE. MODEL CONSISTENCY HAS LED TO
ENOUGH CONFIDENCE TO GO AHEAD AND ISSUE SMALL CRAFT ADVISORY
BEGINNING TONIGHT AND LASTING THROUGH FRIDAY AFTERNOON. AT LEAST A
SMALL CRAFT USE CAUTION HEADLINE WILL LIKELY BE NEEDED BEYOND THAT
PERIOD. SURFACE HIGH PRESSURE WILL SLIDE OFF TO THE EAST INTO THE
WEEKEND...BUT STILL EXPECTED TO HAVE ELEVATED EASTERLY WINDS.
MEFFER
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 70 38 54 30 / 0 10 10 10
BTR 73 39 55 32 / 0 10 10 10
MSY 71 46 57 41 / 0 10 10 10
GPT 70 40 55 30 / 0 10 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY TO 6 PM FRIDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM PASCAGOULA MS TO THE
SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
NM...COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER
ATCHAFALAYA RIVER LA FROM 20 TO 60 NM...COASTAL WATERS FROM
THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER
ATCHAFALAYA RIVER LA OUT 20 NM...AND LAKE PONTCHARTRAIN AND
LAKE MAUREPAS.
MS...NONE.
GM...SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY TO 6 PM FRIDAY FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM PASCAGOULA MS TO THE
SOUTHWEST PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60
NM...COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER
ATCHAFALAYA RIVER LA FROM 20 TO 60 NM...COASTAL WATERS FROM
THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO LOWER
ATCHAFALAYA RIVER LA OUT 20 NM...AND LAKE PONTCHARTRAIN AND
LAKE MAUREPAS.
&&
$$
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