[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201705
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 20 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 28W S OF 18N MOVING W NEAR 10 KT. THE
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM ACROSS THE
EASTERN TROPICAL ATLC AS OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. GLOBAL MODEL GUIDANCE FIELDS OF 850 MB RELATIVE
VORTICITY AND 700 MB STREAMLINES ALSO DEPICT CYCLONIC TURNING IN
THE VICINITY OF THE WAVE AXIS BETWEEN 23W-29W. SCATTERED SHOWERS
AND ISOLATED MODERATE CONVECTION ARE LOCATED E OF THE WAVE FROM
14N-17N BETWEEN 21W-26W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 6N20W 13N36W 8N50W 7N60W. A
1009 MB SURFACE LOW IS EMBEDDED WITHIN THE AXIS CENTERED NEAR
13N36W. SCATTERED MODERATE CONVECTION IS NE OF THE CENTER FROM
14N-16N BETWEEN 31W-35W. ELSEWHERE...CLUSTERS OF ISOLATED
MODERATE CONVECTION ARE FROM 4N-7N BETWEEN 13W-18W.

...DISCUSSION...

GULF OF MEXICO...
A 1028 MB HIGH CENTERED OVER WESTERN NORTH CAROLINA NEAR 36N83W
IS PRODUCING SURFACE RIDGING OVER THE ENTIRE GULF OF MEXICO.
10-15 KT NE WINDS ARE OVER THE E GULF E OF 90W WHILE 10 KT SE
WINDS ARE OVER THE W GULF. BROKEN TO OVERCAST LOW CLOUDS ARE
OVER THE MAJORITY OF THE GULF S OF 29N. IN THE UPPER LEVELS...
AN UPPER LEVEL TROUGH IS OVER THE E GULF AND FLORIDA. AN UPPER
LEVEL HIGH IS CENTERED OVER S MEXICO NEAR 18N100W. UPPER LEVEL
RIDGING IS OVER THE W GULF W OF 90W PRODUCING NW FLOW. STRONG
SUBSIDENCE IS OVER THE E GULF E OF 90W WHILE CONSIDERABLE
MOISTURE IS OVER THE W GULF. EXPECT...SURFACE HIGH PRESSURE
RETURN FLOW WITH SURFACE CONFLUENCE TO PRODUCE CONVECTION OVER
THE NW GULF AND E TEXAS OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
A DISSIPATING STATIONARY FRONT EXTENDS FROM E CUBA TO S OF THE
CAYMAN ISLANDS ALONG 21N77W 18N82W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 18N-21N BETWEEN 76W-84W. SIMILAR CONVECTION
IS OVER THE GULF OF HONDURAS FROM 16N-18N BETWEEN 84W-87W. A
QUASI-STATIONARY 1007 MB LOW IS CENTERED OVER THE SW CARIBBEAN
NEAR 11N82W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 9N-14N
BETWEEN 77W-84W. THE E CARIBBEAN E OF 70W HAS MOSTLY FAIR
WEATHER. SCATTERED SHOWERS ARE HOWEVER OVER THE SOUTHERN
WINDWARD ISLANDS.  15 KT NE WINDS ARE OVER THE YUCATAN CHANNEL
AND NW CARIBBEAN N OF THE FRONT. MODERATE TO FRESH TRADEWINDS
ARE OVER THE REMAINDER OF THE CARIBBEAN. IN THE UPPER LEVELS...
AN UPPER LEVEL HIGH IS OVER THE SW CARIBBEAN NEAR 12N77W. AN
UPPER LEVEL LOW IS OVER THE E CARIBBEAN NEAR 14N63W.
SIGNIFICANT UPPER LEVEL MOISTURE IS OVER THE W CARIBBEAN W OF
70W. STRONG SUBSIDENCE IS OVER THE E CARIBBEAN. EXPECT...THE
FRONT TO DISSIPATE OVER THE NEXT 24 HOURS. ALSO EXPECT THE
SURFACE LOW TO DEEPEN SLIGHTLY WITH CONVECTION.

ATLANTIC OCEAN...
THE TAIL END OF A COLD FRONT IS OVER THE W ATLANTIC FROM 32N61W
TO 30N63W. A STATIONARY FRONT CONTINUES TO E CUBA ALONG 25N70W
21N77W. WIDELY SCATTERED MODERATE CONVECTION IS OVER THE S
BAHAMAS FROM 21N-26N BETWEEN 67W-77W. A SURFACE TROUGH IS OVER
THE CENTRAL ATLANTIC ALONG 27N55W 19N55W. A 1022 MB HIGH IS OVER
THE CENTRAL ATLANTIC NEAR 35N40W. ANOTHER SURFACE TROUGH IS OVER
THE E ATLANTIC ALONG 30N29W 26N30W. IN THE UPPER LEVELS...AN
UPPER LEVEL TROUGH IS OVER THE W ATLANTIC N OF 20N AND W OF 70W.
AN UPPER LEVEL RIDGE IS BETWEEN 60W-70W. AN UPPER LEVEL LOW IS
OVER THE CENTRAL ATLANTIC NEAR 24N51W. UPPER LEVEL DIFFLUENCE E
OF THE CENTER IS PRODUCING WIDELY SCATTERED MODERATE CONVECTION
FROM 20N-27N BETWEEN 42W-50W. AN UPPER LEVEL HIGH IS OVER THE
TROPICAL ATLANTIC NEAR 5N40W. AN UPPER LEVEL RIDGE AXIS EXTENDS
NE FROM THIS CENTER TO 24N27W. EXPECT...MORE CONVECTION ALONG
THE ITCZ ESPECIALLY E OF 40W OVER THE NEXT 24 HOURS.

$$
FORMOSA




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