[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 260608
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 26 2008

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

...SPECIAL FEATURES...
TROPICAL STORM KYLE IS CENTERED NEAR 24.8N 68.0W OR ABOUT 480 NM
SSW OF BERMUDA AT 26/0300 UTC MOVING N AT 7 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED
IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS. KYLE IS EXPERIENCING WESTERLY SHEAR AND
IS EXPECTED TO CONTINUE FRO THE NEXT 12 HOURS OR SO THEN
DIMINISH ALLOWING KYLE TO INTENSIFY TO A HURRICANE IN 36-48
HOURS AS IT MOVES OVER WARM WATERS AT A FAIRLY SPEEDY CLIP.
SCATTERED MODERATE/STRONG CONVECTION IS E OF THE CENTER FROM
22N-26N BETWEEN 61W-68W.

A NON-TROPICAL 990 MB LOW PRESSURE IS CENTERED JUST OFF THE
SOUTH CAROLINA COAST MOVING WNW NEAR 10 KT. THE LOW CONTINUES TO
BE EMBEDDED WITHIN A FRONTAL ZONE AND THE POSSIBILITY THAT THIS
SYSTEM DEVELOPS INTO A SUBTROPICAL OR TROPICAL CYCLONE BEFORE
MOVING INLAND OVERNIGHT IS DIMINISHING.  STRONG WINDS...COASTAL
FLOODING...HIGH SURF...AND DANGEROUS RIP CURRENTS WILL CONTINUE
ALONG PORTIONS OF THE U.S. EAST COAST DURING THE NEXT DAY OR
TWO.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 28W S OF 17N MOVING W NEAR 10 KT. THE N
PORTION OF THE WAVE IS EMBEDDED WITHIN A SMALL AREA OF DEEP
LAYERED MOISTURE AS INDICATED BY MIMIC TPW ANIMATION. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 13N-16N BETWEEN
25W-30W.

TROPICAL WAVE IS ALONG 39W/40W S OF 17N MOVING W NEAR 10 KT.
WAVE HAS EXPANDED OVER THE PAST COUPLE OF DAYS WITH THE AXIS
ALONG THE INVERTED-V CURVATURE...THUS THE REPOSITIONING THAT
OCCURRED ON THU. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 10N-17N BETWEEN 33W-42W.

TROPICAL WAVE IS ALONG 70W/71W S OF 15N MOVING W 10-15 KT.
WAVE POSITION CONTINUES TO BE BASED ON CONTINUITY AS IT IS
EMBEDDED WITHIN DRY STABLE AIR...THUS NO CLOUDS OR SHOWER
ACTIVITY.

TROPICAL WAVE IS ALONG 85W S OF 16N MOVING W 10-15 KT. WEAK LOW
LEVEL INVERTED-V CURVATURE IS OBSERVED IN THE GULF OF HONDURAS.
HOWEVER...ANY SHOWERS/CONVECTION ARE INLAND OVER CENTRAL
AMERICA.

TROPICAL WAVE IS ALONG 95W/96W S OF 20N MOVING W 10-15 KT. THE
WAVE IS BECOMING LESS IDENTIFIABLE ON SATELLITE IMAGERY AS THE
ACTIVITY IN THE BAY OF CAMPECHE IS ASSOCIATED WITH A MID LEVEL
TROUGH AND UPPER LEVEL RIDGE THAT DOMINATES THAT AREA.

...THE ITCZ...
ITCZ AXIS IS ANALYZED ALONG 14N16W 8N29W 10N39W 8N47W 9N60W.
CLUSTERS OF SCATTERED STRONG CONVECTION ARE FROM 11N-14N E OF
19W TO INLAND OVER W AFRICA. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-11N BETWEEN
13W-18W AND ALONG THE COAST OF SW AFRICA.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH COVERS E US COAST...THE GULF N OF 26N...
AND THE W ATLC WITH THE LOW PRESSURE AREA IN THE SPECIAL
FEATURES EMBEDDED WITHIN THIS TROUGH. DRY STABLE UPPER AIR
COVERS THE N GULF FROM CORPUS CHRISTI ACROSS THE N FLORIDA
PENINSULA INTO THE W ATLC. AN UPPER RIDGE AXIS EXTENDS FROM OVER
S MEXICO AND THE YUCATAN PENINSULA ACROSS THE NW CARIBBEAN INTO
THE W ATLC. UPPER DIFFLUENCE COUPLED WITH THE TROPICAL WAVE IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 23N W
OF 85W TO INLAND OVER MEXICO AND THE YUCATAN PENINSULA. ISOLATED
SHOWERS/THUNDERSTORMS ARE OVER THE SE GULF S OF 25N BETWEEN
81W-85W. THE N GULF REMAINS CLEAR TONIGHT.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN
W OF A LINE FROM THE E TIP OF CUBA TO CENTRAL NICARAGUA WITH THE
DEEP LAYERED TROUGH OVER THE W ATLC EXTENDING A SHEAR AXIS
ACROSS HAITI TO NEAR 14N78W. UPPER LEVEL DIFFLUENCE CONTINUES TO
GENERATING ISOLATED SHOWERS N OF 20N W OF 83W TO OVER THE
YUCATAN AND THROUGH THE YUCATAN CHANNEL. AN UPPER RIDGE IS
ANCHORED OVER THE NE CARIBBEAN JUST S OF PUERTO RICO COVERING
THE REMAINDER OF THE AREA. UPPER DIFFLUENCE IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE LESSER
ANTILLES AND INTO THE W ATLC N OF 13N W OF 63W AND N OF 17N FROM
63W-68W INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. THE
CENTRAL CARIBBEAN IS UNDER STRONG SUBSIDENCE AND DRY STABLE AIR
KEEPING THE AREA FROM 66W-83W REMARKABLY CLEAR AGAIN TONIGHT.

ATLANTIC OCEAN...
TWO MAIN CONCERNS FOR THE W ATLC TONIGHT ARE THE ACTIVITY
DESCRIBED IN THE SPECIAL FEATURES ABOVE. THE DEEP LAYERED TROUGH
ASSOCIATED WITH THE LOW PRESSURE SYSTEM GOING INTO SOUTH
CAROLINA N OF 26N W OF 70W WITH A SHEAR AXIS EXTENDING FROM
26N74W INTO THE CARIBBEAN OVER HAITI. THE ASSOCIATED STATIONARY
FRONT IS BEGINNING TO WEAKEN AND ENTERS THE REGION NEAR 32N72W
ACROSS THE N BAHAMA ISLANDS NEAR 25N78W THEN WEAKENING THROUGH
THE FLORIDA STRAITS. ISOLATED SHOWERS ARE FROM 24N-27N W OF 76W.
A WEAK SURFACE TROUGH EXTENDS FROM THE LOW CENTER THROUGH 32N76W
TO 27N76W. AN UPPER RIDGE IS TO THE E OVER T.S. KYLE EXTENDING
FROM THE CARIBBEAN UPPER HIGH S OF PUERTO RICO TO 32N64W
COVERING THE REMAINDER OF THE W ATLC. WEAK CUT-OFF UPPER LOW
REMAINS IN THE CENTRAL ATLC NEAR 23N48W AND AN DEEP LAYERED
TROUGH BEGINNING TO PUSH S ENCOMPASSING THIS UPPER LOW. THE
ASSOCIATED FRONTAL BOUNDARY WITH THE DEEP LAYERED TROUGH ENTERS
THE CENTRAL ATLC NEAR 32N40W ALONG 29N50W THEN NW TO BEYOND
32N57W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 75 NM OF LINE FROM 28N50W TO BEYOND 32N42W. A DEEP
LAYERED LOW IS IN THE E ATLC N OF 24N E OF 32W TO OVER THE
CANARY ISLANDS WITH THE UPPER LOW BEGINNING TO WEAK AND BECOMING
ELONGATED NEAR 29N22W AND AN EQUALLY WEAK 1014 MB SURFACE LOW
NEAR 31N24W WITH A SURFACE TROUGH EXTENDING S TO 24N26W
GENERATING ISOLATED SHOWERS WITHIN 60 NM OF THE SURFACE LOW. THE
TYPICAL E/W UPPER RIDGE THAT EXTENDS FROM AFRICA TO NEAR 42W
ALONG 15N IS BEGINNING TO EXPAND FURTHER N AS THE UPPER TROUGH
MENTIONED ABOVE WEAKENS.

$$
WALLACE




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