[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071026
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI SEP 07 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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
0945 UTC.

...SPECIAL FEATURES...
A 1012 MB LOW LOCATED ABOUT 360 NM SW OF BERMUDA NEAR 28.5N70W
WITH A SURFACE TROUGH EXTENDING SSW FROM THE LOW TO NEAR 24N72W.
THE LOW-LEVEL CENTER REMAINS COMPLETELY EXPOSED BUT IS STARTING
TO DRIFT NORTHWARDS. THERE ARE SCATTERED SHOWERS/THUNDERSTORMS N
AND E OF THE LOW ASSOCIATED WITH A WEAKENING FRONTAL BOUNDARY
ALONG 32. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 27N
FROM 70W-77W WITH SHOWERS/THUNDERSTORMS BETWEEN THE BAHAMAS AND
CUBA W OF 76W THROUGH THE FLORIDA STRAITS INTO THE GULF OF
MEXICO. THE SYSTEM CONTINUES TO INTERACT WITH AN UPPER TROUGH TO
THE W OF THE SURFACE LOW/TROUGH. UPPER-LEVEL WINDS ARE CURRENTLY
NOT FAVORABLE FOR DEVELOPMENT. HOWEVER...CONDITIONS COULD BECOME
MORE FAVORABLE AS THE LOW MOVES TOWARD THE N/NW AND A
SUBTROPICAL OR TROPICAL CYCLONE COULD FORM DURING THE NEXT
COUPLE OF DAYS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 20W/21W S OF 19N MOVING W 10-15 KT. BROAD
LOW/MID LEVEL CYCLONIC ROTATION COVERING THE AREA FROM 7N-19N
BETWEEN 14W-25W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 9N-14N BETWEEN 18W-25W.

TROPICAL WAVE IS TILTED FROM 23N44W ALONG 14N47W TO 6N47W MOVING
W 10-15 KT. VERY BROAD LOW/MID LEVEL INVERTED-V CURVATURE IS
COVERING THE AREA S OF 22N FROM 40W-52W. NO ASSOCIATED DEEP
CONVECTION WITH SCATTERED SHOWERS/THUNDERSTORMS FROM 15N-20N
BETWEEN 46W-60W.

TROPICAL WAVE IS ALONG 78W/79W S OF 19N MOVING W 10-15 KT. WAVE
REMAINS EMBEDDED WITHIN SOME RATHER DRY STABLE AIR OVER THE
CARIBBEAN MASKING THE SATELLITE SIGNATURE AND LIMITING ANY
ASSOCIATED SHOWERS/DEEP CONVECTION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N13W 5N29W 9N52W 8N59W. A VERY
WEAK NEAR STATIONARY 1014 MB LOW IS NEAR 14N43W AND IS
CHARACTERIZED BY A SMALL LOW LEVEL SWIRL WITH NO SHOWER
ACTIVITY. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 150 NM OF THE ITCZ AXIS E OF 44W TO THE
COAST OF W AFRICA.

DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDS FROM THE TEXAS/LOUISIANA BORDER SE
TO W CUBA/YUCATAN CHANNEL INTO THE NW CARIBBEAN COVERING MOST OF
THE GULF. A SMALL UPPER HIGH IS NEAR THE REMNANTS OF FELIX THAT
ARE JUST INLAND ALONG THE COAST OF S MEXICO NEAR 18.5N95.5W AND
CONTINUE TO GENERATE SCATTERED MODERATE/STRONG CONVECTION IN THE
W BAY OF CAMPECHE S OF 22N W OF 94W. THE UPPER RIDGE OVER THE
GULF COUPLED WITH THE UPPER TROUGH IN THE W ATLC THAT EXTENDS
OVER FLORIDA CONTINUES TO GENERATE SCATTERED SHOWERS/
THUNDERSTORMS OVER THE E GULF WITHIN 125/150 NM OF LINE FROM THE
N GULF COAST NEAR THE MISSISSIPPI DELTA SW OVER CUBA NEAR
HAVANA. THE REMAINDER OF THE AREA REMAINS TRANQUIL THIS MORNING
WITH LIGHT SURFACE WINDS.

CARIBBEAN SEA...
THE UPPER LEVEL RIDGE FROM THE GULF OF MEXICO COVERS THE NW
CARIBBEAN N OF 16N W OF 80W AND THE UPPER TROUGH OVER THE W ATLC
DIPS ACROSS CUBA TO 18N FROM 75W-81W. THIS IS GENERATING
SCATTERED SHOWERS/THUNDERSTORMS N OF 20N FROM 80W-85W. AN UPPER
LEVEL TROUGH EXTENDS FROM CENTRAL PANAMA TO OVER CENTRAL
NICARAGUA GENERATING SHOWERS/THUNDERSTORMS WITHIN 75/90 NM OF
LINE FROM PANAMA NEAR 9N80W TO JUST OVER NICARAGUA NEAR 14N84W.
AN UPPER LOW IS JUST N OF HAITI EXTENDS AN UPPER TROUGH OVER THE
CENTRAL CARIBBEAN TO 15N FROM 68W-75W GENERATING ISOLATED
SHOWERS/THUNDERSTORMS OVER HAITI AND THE GULF OF GONAVE. DRY
STABLE AIR COVERS THE REMAINDER OF THE CARIBBEAN E OF 80W IS
GIVING THAT AREA CLEAR SKIES WITH THE EXCEPTION OF THE AREAS
MENTIONED ABOVE WITH MODERATE/STRONG EASTERLY TRADE WINDS.

ATLANTIC OCEAN...
AN UPPER TROUGH AXIS EXTENDS INTO THE W ATLC THROUGH 32N72W TO
ACROSS CUBA NEAR 22N78W COVERING MOST OF THE W ATLC WITH THE
ASSOCIATED 1012 MB LOW AND SURFACE TROUGH MENTIONED IN THE
SPECIAL FEATURES ABOVE. A SECOND UPPER LOW IS JUST N OF HAITI
EXTENDING A TROUGH S INTO THE CENTRAL CARIBBEAN. THIS FEATURE IS
BEING ABSORBED INTO THE UPPER TROUGH OVER THE REMAINDER OF THE W
ATLC. A BROAD UPPER HIGH IS IN THE CENTRAL ATLC NEAR 28N52W
COVERING THE AREA N OF 20N FROM 30W-67W. A BROAD UPPER TROUGH
DIPS INTO THE E ATLC N OF 26N E OF 30W TO OVER NW AFRICA. A WEAK
MID/UPPER LOW IS IN THE W TROPICAL ATLC NEAR 14N56W AND COVERS
THE AREA S OF 20N FROM 50W ACROSS THE LESSER ANTILLES TO NEAR
63W. THE REMAINDER OF THE TROPICAL ATLC IS DOMINATED BY EASTERLY
UPPER FLOW. ALL THESE UPPER FEATURES ARE RATHER BENIGN COUPLED
WITH THE ABUNDANCE DRY AIR ALOFT AND A SURFACE RIDGE COVERING
THE ATLC E OF 65W ANCHORED BY A 1022 MB HIGH IN THE CENTRAL ATLC
NEAR 27N56W AND A 1020 MB HIGH IN THE E ATLC NEAR 27N26W ARE
GIVING THE MUCH OF THE ATLC FAIR WEATHER CLOUDS WITH LIGHT TO
MODERATE EASTERLY TRADE WINDS.

$$
WALLACE





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