[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 092346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI MAR 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 4N20W 3N35W EQ44W TO THE NE
COAST OF BRAZIL NEAR 2S46W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS WITHIN 80 NM ON EITHER SIDE OF THE AXIS
BETWEEN 32W-42W...AND WITHIN 150 NM S OF THE AXIS E OF 15W.
SIMILAR CONVECTION IS OVER NE BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
WEAK PRES PATTERN CHARACTERIZED BY WEAK RIDGING AND A VERY WEAK
SFC TROUGH DOMINATES THE GULF. THE TROUGH IS OVER THE CENTRAL
GULF ALONG 88/89W FROM 23N-28N. THIS FEATURE IS GENERATING AN
AREA OF LOW AND MID CLOUDS WITH POSSIBLE SHOWERS WITHIN 60-80 NM
OF THE AXIS. ELY WINDS ACROSS THE REGION ARE ADVECTING SOME LOW
LEVEL MOISTURE ACROSS THE E SLOPES OF THE SIERRA MADRE
MOUNTAINS. A BROAD UPPER LEVEL RIDGE DOMINATES THE ENTIRE GULF
AND THE SOUTH-CENTRAL PORTIONS OF MEXICO....INCLUDING THE
YUCATAN PENINSULA. SWLY FLOW ON THE WRN PERIPHERY OF THE RIDGE
IS ADVECTING HIGH LEVEL MOISTURE FROM THE EPAC ACROSS CENTRAL
MEXICO AND INTO THE GULF MAINLY S OF 27N. MODERATE DRY AIR
EXISTS N OF THE UPPER MOISTURE PLUME. THE WEAK PATTERN IS
FORECAST TO PERSIST DURING THE UPCOMING WEEKEND WITH FAIRLY
LIGHT WINDS AND SEAS.

CARIBBEAN...
QUIET WEATHER PERSISTS ACROSS MUCH OF THE BASIN THIS EVENING
WITH PLENTY OF DRY STABLE AIR ALOFT IN PLACE. UPPER RIDGING
GENERALLY DOMINATES THE REGION W OF 70W WITH A SHORTWAVE TROUGH
FROM THE ATLC TO THE E CARIBBEAN. CLUSTERS OF MODERATE TO
ISOLATED STRONG CONVECTION HAVE DEVELOPED OVER N COLOMBIA AND W
VENEZUELA NEAR LAKE MARACAIBO PROBABLY ASSOCIATED WITH THE
CLIMATOLOGICAL LOW PRES THAT SITS OVER THE AREA. LOW AND MID
CLOUDS ARE SEEN OVER THE YUCATAN PENINSULA...THE NW CARIBBEAN
AND A GOOD PORTION OF CUBA ASSOCIATED WITH THE REMNANTS OF A
WEAK SFC TROUGH. TYPICAL TRADE WIND SHOWERS ARE MOVING WWD
ACROSS THE REGION. TRANQUIL WEATHER IS EXPECTED TO CONTINUE
THROUGH THE WEEKEND WITH CONDITIONS DOMINATED BY MODERATE TRADE
WINDS.

WESTERN ATLANTIC...
SFC LOW PRES PREDICTED BY THE REGIONAL GLOBAL MODELS DURING THE
PAST FEW DAYS IS LOCATED JUST E OF THE BAHAMAS NEAR 25N74W AT
21Z. A TROUGH EXTENDS FROM THIS LOW TO THE WINDWARD PASSAGE
WHILE ANOTHER TROUGH GOES MAINLY EWD FROM THE LOW TO 26N65W.
A COLD FRONT IS ALSO IN THE AREA WITHIN 90-100 NM N OF THE
SECOND TROUGH MENTIONED ABOVE. MULTILAYERED CLOUDS WITH
EMBEDDED NUMEROUS SHOWERS AND SCATTERED TSTMS ARE ASSOCIATED
WITH ALL THESE FEATURES. SAT IMAGERY ALSO SHOWS THE CLOUD
PATTERN EXHIBITING CYCLONIC CIRCULATION DUE TO THE PRESENCE OF
THE LOW PRES. THE PRES GRADIENT RESULTING BETWEEN STRONG HIGH
PRES N OF THE AREA AND THE SFC LOW HAS TIGHTENED PRODUCING NE TO
E WINDS OF 20 TO 30 KT N OF 27N E OF 75W. ACCORDING TO THE GFS
MODEL...THE SFC LOW JUST E OF THE BAHAMAS WILL MOVE NE ACROSS
THE OCEAN INTENSIFYING INTO A STRONG EXTRATROPICAL WITH A
TRAILING FRONTAL TROUGH.

EASTERN ATLANTIC...
A STRONG 1039 MB HIGH PRES SYSTEM LOCATED ABOUT 300 NM W OF
PORTUGAL 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 TO THE
W COAST OF AFRICA WHERE THE TIGHTEST PRES GRAD EXISTS. FAIRLY
DRY AIR ALOFT DOMINATES THE REGION PROVIDING STABLE CONDITIONS.
THE STRONG SFC HIGH IS FORECAST TO RETREAT NE ALLOWING THE
TRADES TO RELAX SLIGHTLY THIS WEEKEND IN THE E ATLC. HOWEVER
THEY ARE SET TO PICK UP AGAIN SUN AND INTO NEXT WEEK AS STRONG
HIGH PRES REBUILDS E ACROSS THE ATLC OCEAN.

$$
GR




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