[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU MAR 08 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1100 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N11W 3N18W 2N29W 1N41W EQ50W.
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE
AXIS BETWEEN 19W-21W AND FROM 1S-1N BETWEEN 30W-33W. ISOLATED
MODERATE IS WITHIN 120 NM EITHER SIDE W OF 36W.

...DISCUSSION...

GULF OF MEXICO...
MAINLY QUIET WEATHER CONTINUES IN THE GULF THANKS TO A WEAK SFC
RIDGE THAT STRETCHES ACROSS THE AREA. SHIP/BUOY OBS AND NIGHT
CHANNEL VIS IMAGES SHOW LIGHT VARIABLE WINDS AND SCATTERED
PATCHES OF LOW-MID LEVEL CLOUDS BETWEEN 85W-95W. AN EXTREMELY
WEAK SFC TROUGH MAY BE FORMING ALONG 87W FROM 26N-29N BUT THIS
WAS NOT SHOWN ON THE 09Z MAP DUE TO ITS VERY FEEBLE STRUCTURE.
IN THE MID AND UPPER LEVELS...THE FLOW IS MAINLY FROM THE WNW
BENDING AROUND AN UPPER RIDGE THAT EXTENDS NWD FROM THE TROPICAL
EPAC INTO THE BAY OF CAMPECHE. SWLY FLOW ON THE W PERIPHERY OF
THIS RIDGE IS SPREADING HIGH LEVEL MOISTURE FROM THE EPAC INTO
CENTRAL MEXICO AND THE WRN GULF...W OF 90W FROM 23N-27N.
MODESTLY DRY AIR EXISTS ELSEWHERE AIDING IN THE TRANQUIL
WEATHER. OVER THE NEXT COUPLE OF DAYS...LITTLE PATTERN CHANGE IS
ANTICIPATED BOTH AT THE SFC AND ALOFT KEEPING WINDS LIGHT AND
THE WEATHER CONDITIONS MAINLY FAIR ACROSS MOST OF THE AREA.

CARIBBEAN...
THE WEAK LOW THAT WAS DRIFTING W IN THE NW CARIB APPEARS TO HAVE
OPENED INTO A TROUGH ANALYZED ALONG 87W FROM THE COAST OF
HONDURAS TO THE NE YUCATAN. THE MAIN EFFECT OF THIS WEAK SYSTEM
IS AN AREA OF LOW TO MID LEVEL CLOUDS WHICH LIE ACROSS NRN
CENTRAL AMERICA AND THE COASTAL WATERS FROM 15N-22N W OF 85W.
THE MOIST ONSHORE FLOW IS RUNNING UPSLOPE SOME OF THE HIGH
TERRAIN LIKELY PRODUCING ISOLATED SHOWERS OVER HONDURAS
...GUATEMALA AND THE YUCATAN PENINSULA. ELSEWHERE FAIRLY TYPICAL
CONDITIONS EXIST WITH MODERATE TO STRONG ELY TRADES AND THIN
PATCHES OF LOW-LEVEL MOISTURE STREAMING W ACROSS THE SEA.
ALOFT...THERE IS SLIGHT TROUGHING EXTENDING SWD FROM ATLC ACROSS
THE WINDWARD PASSAGE AND JAMAICA TO 15N81W. THIS TROUGH IS
ENHANCING THE WIDESPREAD DRY STABLE AIR PREVENTING THE MOISTURE
PATCHES FROM ACQUIRING MUCH VERTICAL DEPTH. THE WEAK SFC TROUGH
ALONG THE CENTRAL AMERICAN COAST WILL DRIFT INLAND AND LIKELY
DISSIPATING LATER TODAY. TRADE WINDS MAY RELAX LATE FRI AND THIS
WEEKEND AS THE STRONG RIDGE IN THE E ATLC RETREATS AND LOW PRES
DEVELOPS N OF THE REGION. OTHERWISE LITTLE CHANGE IS EXPECTED
OVER THE NEXT FEW DAYS.

WESTERN ATLANTIC...
SLIGHT MID TO UPPER LEVEL TROUGHING COVERS THE MAJORITY OF THE
ATLC W OF 50W EXTENDING SWD FROM A LARGE STRONG POLAR LOW. AN
ASSOCIATED WEAKENING FRONTAL BOUNDARY IS LINGERING IN THE REGION
ANALYZED STATIONARY ALONG 32N46W 26N55W THEN DISSIPATING TO
26N66W. BROKEN TO OVERCAST LOW AND MID LEVEL CLOUDS WITH
EMBEDDED ISOLATED SHOWERS ARE WITHIN 180 NM BEHIND THE FRONT.
THICKER CLOUD COVER LIES FURTHER W ACROSS THE BAHAMAS WHERE A
SFC TROUGH HAS FORMED. SCATTERED SHOWERS ARE EMBEDDED IN THIS
CLOUD COVER AS DEPICTED BY DOPPLER RADAR FROM THE BAHAMAS. THIS
TROUGH IS LIKELY A RESULT OF ENERGY THAT BROKE OFF FROM THE
WEAKENING FRONT AND ENHANCED BY AN UPPER SHORTWAVE. SE OF THE
FRONT...SKIES ARE MAINLY FAIR UNDER THE INFLUENCE OF SFC HIGH
PRES RIDGING FROM THE NE AND DRY STABLE AIR ALOFT. LOOKING AHEAD
A COUPLE OF DAYS...THE LARGE POLAR VORTEX WILL GRADUALLY PULL
EWD BUT THERE STILL SHOULD BE SOME SUPPORT FOR THE WEAK SFC
TROUGH IN THE BAHAMAS. GFS SHOWS THIS FEATURE MERGING WITH A
COLD FRONT CURRENTLY OFF THE SE U.S. ON FRI. THIS WILL LIKELY
CONTINUE TO PRODUCE SOME UNSETTLED WEATHER FOR PORTIONS OF THE W
ATLC.

EASTERN ATLANTIC...
A STRONG 1035 MB HIGH PRES SYSTEM LOCATED A COUPLE HUNDRED NM E
OF THE AZORES IS DOMINATING THE SFC PATTERN ACROSS THE ATLC E OF
45W. THIS HIGH IS PRODUCING MODERATE TO STRONG TRADE WINDS
ACROSS A GOOD PORTION OF THE DISCUSSION AREA PARTICULARLY E OF
30W WHERE A TIGHT PRES GRAD EXISTS BETWEEN THIS HIGH AND LOW
PRES IN THE MEDITERRANEAN. THE ONCE VIGOROUS UPPER LOW HAS
OPENED INTO A TROUGH ALIGNED ALONG 34W. SWLY UPPER LEVEL FLOW
AND DIFFLUENCE TO THE E OF THE TROUGH AXIS IS STILL GENERATING
PATCHY MID-HIGH LEVEL MOISTURE FROM 16N TO BEYOND 32N BETWEEN
23W-34W. THIS MOISTURE PLUME IS SUBSTANTIALLY THINNER THAN IT
WAS YESTERDAY AT THIS TIME AND THIS TREND IS EXPECTED TO
CONTINUE AS THE TROUGH PULLS NWD AND DISSIPATES LATER TODAY OR
FRI. FAIR WEATHER LOOKS TO BE THE THEME FOR MOST OF THE REGION
THIS WEEKEND AS STRONG DEEP LAYER RIDGING BECOMES WELL
ESTABLISHED.

$$
CANGIALOSI





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