[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041222
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 04 2005

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURE...
THE CENTER OF TROPICAL STORM HARVEY IS NEAR 31.9N 63.9W OR ABOUT
55 MILES/90 KM SOUTHEAST OF BERMUDA AT 04/1200 UTC. IT IS MOVING
EAST-NORTHEAST 11 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 995 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO
60 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC OR MIATCPAT3/WTNT33 KNHC FOR MORE
DETAILS. HARVEY IS EMBEDDED WITHIN THE WESTERLIES AND CONVECTION
HAS INCREASED NEAR THE CENTER. AN UPPER LEVEL SHORTWAVE TROUGH
IS NOW E OF HARVEY THE STORM IS HOLDING ITS OWN WITH WSW SHEAR.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF
LINE 30.5N65W-34N62W.

...TROPICAL WAVES...

A 1009 MB LOW IS CENTERED TO THE E OF A TROPICAL WAVE NEAR
12N30W DRIFTING WNW. AN AREA OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS W OF THE LOW TO BEYOND THE TROPICAL WAVE
FROM 10.5N-15.5N BETWEEN 30W-36W.

TROPICAL WAVE IS ALONG 34W/35W S OF 18N MOVING W 10 KT. LOW
CLOUD SIGNATURE CURVATURE IS PARTIALLY OBSCURED DUE TO MID/HIGH
CLOUDS MAKING THE LOCATION OF THE WAVE DIFFICULT TO FIND. DEEP
CONVECTION IS EMBEDDED WITHIN THE ITCZ.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 74W S OF 20N MOVING W
10 KT. WEAK SIGNATURE CURVATURE IS OBSERVED IN SOME LOW CLOUDS
JUST S OF HISPANIOLA. WAVE REMAINS AT THE BASE OF AN UPPER HIGH
THAT EXTENDS INTO THE CARIBBEAN FROM THE W ATLC. THIS IS DRYING
THE AREA IN THE CARIBBEAN...THUS NO ASSOCIATED DEEP CONVECTION.

W CARIBBEAN TROPICAL WAVE IS ALONG 85W S OF 21N MOVING W 10 KT.
WEAK CURVATURE IS OBSERVED IN SOME LOW CLOUDS OVER THE FAR NW
CARIBBEAN. UPPER LEVEL W WINDS ARE KEEPING THE AREA DRY MAKING
THE EXACT LOCATION HARD TO DETERMINE. SCATTERED THUNDERSTORMS
ARE INLAND OVER NICARAGUA/HONDURAS AND WITHIN 60 NM  ALONG THE
COAST OF HONDURAS W OF 85.

...ITCZ...

ITCZ AXIS CENTERED ALONG 14N16W 13N22W 14N28W 10N32W 9N39W
10N50W 8N60W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 5N-11N E OF 41W TO THE COAST OF AFRICA.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM OF
THE AXIS FROM 41W-60W.

...DISCUSSION...

GULF OF MEXICO...
WEAK HIGH SURFACE PRESSURE CONTINUES ACROSS THE GULF WITH LIGHT
WINDS ACROSS THE AREA WITH A 1017 MB HIGH ALONG THE COAST OF W
LOUISIANA NEAR 29N93W. MID/UPPER LEVEL TROUGH EXTENDS FROM AN
MID/UPPER LOW OVER SW TEXAS/N MEXICO ALONG 28N97W INTO THE
CENTRAL GULF NEAR 26N86W. AN UPPER HIGH IN THE W ATLC IS GIVING
THE E GULF S FLOW. UPPER DIFFLUENCE OVER THE CENTRAL GULF IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 28N-31N
BETWEEN 82W-92W. W UPPER FLOW OVER THE BAY OF CAMPECHE IS
GENERATING SIMILAR ACTIVITY S OF 20N FROM ACROSS MEXICO TO OVER
THE YUCATAN PENINSULA. ISOLATED SHOWERS DOT THE REMAINDER OF THE
GULF. UPPER LEVEL TROUGH WILL SPREAD E COVERING THE ENTIRE GULF
OVER THE NEXT 12 TO 24 HOURS WITH A CUT-OFF LOW DEVELOPING OVER
THE WEEKEND. MOISTURE OVER THE N GULF WILL CONTINUE FOR THE NEXT
DAY OR SO DRIFTING INTO THE W ATLC WHILE THE S GULF MOISTURE
WILL INCREASE WITH THE PASSAGE OF A TROPICAL WAVE CURRENTLY IN
THE W CARIBBEAN.

CARIBBEAN SEA...
WEAKENING UPPER LOW IS OVER THE N CARIBBEAN JUST S OF CUBA NEAR
21N81W WITH CYCLONIC FLOW N OF 16N FROM 76W-85W. MID/UPPER HIGH
IS N OF THE DOMINICAN REPUBLIC NEAR 21N70W WITH ANTICYCLONIC
FLOW N OF 15N FROM 65W-75W. DIFFLUENCE BETWEEN THESE UPPER LEVEL
SYSTEMS IS GENERATING A SMALL AREA OF ISOLATED SHOWERS FROM 18N
TO OVER CUBA BETWEEN HAITI AND 81W INCLUDING JAMAICA. W UPPER
FLOW FROM A UPPER HIGH IN THE E PACIFIC IS ADVECTING TROPICAL
MOISTURE ACROSS THE S CARIBBEAN AND A DEVELOPING MID/UPPER HIGH
IN THE SW CARIBBEAN IS GENERATING A LINE OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION WITHIN 60 NM OF LINE FROM THE COAST
OF PANAMA NEAR 8.5N77.5W TO JUST INLAND OVER NICARAGUA NEAR
12.5N84W. SCATTERED/NUMEROUS STRONG CONVECTION IS S OF 10N E OF
77.5W TO INLAND OVER NW COLOMBIA. REMAINDER OF THE CARIBBEAN IS
UNDER MODERATE SUBSIDENCE AND DRY AIR PRODUCING MOSTLY CLEAR
SKIES EXCEPT IN THE IMMEDIATE AREAS OF THE TROPICAL WAVES. ANY
UPPER LEVEL MOISTURE WILL MOVE OUT OF THE CARIBBEAN BY FRI AS
THE TROPICAL WAVE IN THE W CARIBBEAN MOVES INTO THE GULF OF
MEXICO. THIS WILL DRY OUT THE CARIBBEAN FOR THE FIRST HALF OF
THE WEEKEND.

ATLANTIC OCEAN...
COMPLEX UPPER WEATHER PATTERN CONTINUES OVER THE W ATLC THIS
MORNING. MID/UPPER HIGH IS SW OF HARVEY NEAR 28N72W WITH A RIDGE
AXIS EXTENDING E/W FROM 68W ACROSS FLORIDA INTO THE E GULF.
DIFFLUENCE S OF THE RIDGE AXIS IS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM OF 28N W OF 72W TO
THE COAST OF CENTRAL FLORIDA. MID/UPPER SHORTWAVE TROUGH IS NOW
E OF HARVEY. STRONG MID/UPPER HIGH IS LOCATED JUST N OF THE
DOMINICAN REPUBLIC NEAR 21N69W WITH A RIDGE AXIS EXTENDING NE
ALONG 26N61W WELL INTO THE NORTH CENTRAL ATLC BEYOND 32N56W.
DIFFLUENCE TO THE W OF THE RIDGE AXIS IS GENERATING CLUSTERS OF
SCATTERED SHOWERS/THUNDERSTORMS N OF 22N BETWEEN 57W-66W. OVER
THE CENTRAL ATLC...A MID/UPPER LEVEL TROUGH EXTENDS FROM A
WEAKENING UPPER LOW NEAR 30N42W SW TO A WELL-DEFINED UPPER LOW
IN THE W TROPICAL ATLC NEAR 18N59W THAT IS BECOMING CUT-OFF. THE
UPPER AIR IS VERY DRY WITH MODERATE/STRONG SUBSIDENCE...THUS NO
SHOWER ACTIVITY IS PRESENT. LARGE MID/UPPER HIGH COVERS THE
REMAINDER OF THE ATLC WATERS CENTERED NW OF THE CAPE VERDE
ISLANDS NEAR 21N33W. WELL-DEFINED CLOSED UPPER LOW IS JUST NE OF
THE CANARY ISLANDS NEAR 30N13W BUT WITH THE DRY AIR ALOFT NO
SHOWER ACTIVITY CAN BE FOUND.

$$
WALLACE



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