[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 040559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...
TROPICAL STORM HARVEY IS CENTERED NEAR 31.9N 64.8W AT 04/0600
UTC MOVING ENE AT 11 KT WHICH IS ABOUT 26 NM/30 MILES SOUTH OF
BERMUDA. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 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 BUT THE FORWARD SPEED
COULD VARY OVER THE NEXT DAY OR SO AS UPPER LEVEL SHORTWAVE
TROUGHS MOVE THROUGH THE AREA. ONE SUCH SHORTWAVE IS JUST TO THE
W OF HARVEY AS THE STORM APPROACHES JUST S OF BERMUDA. SMALL
AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS TO THE
E OF THE CENTER WITHIN A 30 NM RADIUS OF 31N65.5W.

...TROPICAL WAVES...

A 1009 MB LOW IS CENTERED TO THE E OF A TROPICAL WAVE NEAR
12N29W DRIFTING NW. THE WAVE CONTINUES TO MOVE AWAY FROM THE
LOW. SCATTERED STRONG CONVECTION ID TO THE NW OF THE LOW FROM
11.5N-14.5N BETWEEN 29W-33W AND TO THE NW OF THE LOW WITHIN 45
NM RADIUS OF 14N27.5W.

TROPICAL WAVE IS ALONG 34W S OF 21N MOVING W 10-15 KT. LOW CLOUD
SIGNATURE CURVATURE IS OBSERVED ON INFRARED SATELLITE IMAGERY.
DEEP CONVECTION IS EMBEDDED WITHIN THE ITCZ.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 73W S OF 21N MOVING W
10 KT. WEAK SIGNATURE CURVATURE IS OBSERVED IN SOME LOW CLOUDS
JUST S OF HISPANIOLA. WAVE IS AT THE BASE OF AN UPPER HIGH THAT
EXTENDS INTO THE CARIBBEAN FROM THE ATLC. THIS IS DRYING THE
AREA IN THE CARIBBEAN...THUS ONLY A SMALL AREA OF THUNDERSTORMS
ARE INLAND OVER NW VENEZUELA.

W CARIBBEAN TROPICAL WAVE IS ALONG 84W S OF 20N MOVING W 10-15
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
MODERATE/STRONG CONVECTION IS W OF 82W TO INLAND OVER NICARAGUA
FROM 11N-14.5N.

...ITCZ...

ITCZ AXIS CENTERED ALONG 13N16W 13N26W 8N37W 9N46W 6N56W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 8N11N BETWEEN
31W-35W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM 6N-13N BETWEEN 21W-45W.

...DISCUSSION...

GULF OF MEXICO...
WEAK HIGH SURFACE PRESSURE CONTINUES ACROSS THE GULF WITH LIGHT
E TO SE WINDS ACROSS THE AREA. MID/UPPER LEVEL TROUGH EXTENDS
FROM AN MID/UPPER LOW OVER SW TEXAS ALONG 28N97W INTO THE
CENTRAL GULF NEAR 24N89W. 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 25N-29N
BETWEEN 84W-90W. W UPPER FLOW OVER THE BAY OF CAMPECHE IS
GENERATING SIMILAR ACTIVITY S OF 21N FROM ACROSS MEXICO THE TO
OVER THE YUCATAN PENINSULA. UPPER LEVEL TROUGH WILL SPREAD E
COVERING THE ENTIRE GULF OVER THE NEXT 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 15N FROM 76W-84W. MID/UPPER HIGH
IS N OF THE DOMINICAN REPUBLIC NEAR 21N69W WITH ANTICYCLONIC
FLOW N OF 13N FROM 63W-76W. DIFFLUENCE BETWEEN THESE UPPER LEVEL
SYSTEMS IS GENERATING A SMALL AREA OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION WITHIN 45 NM RADIUS OF 19N79W WITH
SCATTERED THUNDERSTORMS INLAND AND ALONG THE S COAST OF CENTRAL
CUBA FROM 77W-80W. W UPPER FLOW FROM A UPPER HIGH IN THE E
PACIFIC IS ADVECTING TROPICAL MOISTURE ACROSS THE S CARIBBEAN S
OF 14N W OF 76W WHICH IS SUPPORTING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS. 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 TONIGHT.
MID/UPPER HIGH IS SW OF HARVEY NEAR 27N74W 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 27N W OF 71W TO
INLAND OVER CENTRAL FLORIDA. MID/UPPER SHORTWAVE TROUGH IS JUST
SW OF HARVEY KEEPING THE STORM FROM FURTHER DEVELOPING. STRONG
MID/UPPER HIGH IS LOCATED JUST N OF THE DOMINICAN REPUBLIC NEAR
21N69W WITH A RIDGE AXIS EXTENDING NE ALONG 26N63W WELL INTO THE
NORTH CENTRAL ATLC BEYOND 32N58W. DIFFLUENCE TO THE W OF THE
RIDGE AXIS IS GENERATING CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION WITHIN 150 NM OF LINE FROM 24N64W-TO BEYOND
32N60W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120
NM OF LINE FROM 24N64W TO THE COAST OF CUBA NEAR 21N76W. 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 18N58W...APPROACHING THE LEEWARD
ISLANDS. 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 W OF THE
CANARY ISLANDS NEAR 27N29W. CLOSED UPPER LOW IS JUST NE OF THE
CANARY ISLANDS NEAR 30N12W BUT WITH THE DRY AIR ALOFT NO SHOWER
ACTIVITY CAN BE FOUND. IN THE DEEP TROPICS...A SECOND MID/UPPER
HIGH IS CENTERED W OF THE CAPE VERDE ISLANDS NEAR 17N30W. THIS
IS KEEPING THE CONVECTION TO S OF THE ITCZ AXIS.

$$
WALLACE


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