[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081050
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON AUG 08 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
1015 UTC.

...SPECIAL FEATURES..
TROPICAL STORM HARVEY IS CENTERED NEAR 38.9N 50.3W AT 08/0900
UTC MOVING NE AT 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1001 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS
TO 55 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC OR MIATCPAT3/WTNT33 KNHC FOR MORE
DETAILS. THE LOW LEVEL CENTER IS FULLY EXPOSED TO THE SW OF LESS
INTENSE CONVECTION. HARVEY HAS BEGUN THE TRANSITION TO
EXTRATROPICAL BUT GALE FORCE WINDS WILL CONTINUE FOR SEVERAL
MORE DAYS. SCATTERED MODERATE CONVECTION IS FROM 40N-44N BETWEEN
44W-51W.

TROPICAL STORM IRENE IS CENTERED NEAR 21.9N 48.9W AT 08/0900 UTC
MOVING WNW AT 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
1006 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO
45 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC OR MIATCPAT4/WTNT34 KNHC FOR MORE
DETAILS. CONVECTION HAS LESSEN OVER THE PAST 6 HOURS BUT AND IT
IS POSSIBLE THAT IRENE IS BEGINNING TO WEAKEN. THIS WILL BE
DETERMINED LATER THIS MORNING. THE LOW LEVEL CENTER REMAINS
COVERED UNDER SCATTERED MODERATE CONVECTION WITHIN 30 NM OF LINE
21N48W-23N44.5W.

...TROPICAL WAVES...
E ATLC TROPICAL WAVE IS ALONG 29W S OF 18N MOVING W 10-15 KT.
ALTHOUGH THE SATELLITE PRESENTATION REMAINS WEAK ON
INFRARED...THE FIRST VISIBLE SATELLITE IMAGES HAVE THE SIGNATURE
INVERTED-V CURVATURE CLEARLY OBSERVED. NO ASSOCIATED DEEP
CONVECTION.

CENTRAL ATLC TROPICAL WAVE IS ALONG 60W/61W S OF 19N MOVING W 10
KT. WAVE IS EMBEDDED WITHIN VERY UPPER DRY AIR. THE SIGNATURE
CURVATURE SUGGESTS THAT THIS WAVE IS BROADENING AS IT MOVES INTO
THE E CARIBBEAN. E OF THE WAVE AXIS...SCATTERED MODERATE/
ISOLATED STRONG CONVECTION IS FROM 14N-18N E OF 65W TO OVER THE
LEEWARD ISLANDS. THIS ACTIVITY WILL MOVE E OF THE LEEWARDS OVER
THE NEXT COUPLE OF HOURS. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 11N-14N BETWEEN 56W-60W.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 15N16W 12N24W 10N32W 9N50W 12N60W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 8.5N-12N E OF 18W
TO THE COAST OF W AFRICA. CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 5N-11N BETWEEN 24W-50W.

...DISCUSSION...
GULF OF MEXICO...
MID/UPPER TROUGH EXTENDS FROM OVER THE SE UNITED STATES INTO THE
CENTRAL GULF THROUGH MISSISSIPPI SW TO 27N90W WITH A SURFACE LOW
TO THE E OVER THE W FLORIDA PANHANDLE NEAR PENSACOLA NEAR 30N86W
AND A SURFACE TROUGH EXTENDING SW TO 24N91W. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE OVER THE N GULF N OF 25N E OF 87W
AND N OF 28N FROM 87W-91W. REMAINDER OF THE GULF IS DOMINATED BY
TWO MID/UPPER LEVEL RIDGES. ONE RIDGE EXTENDS N/S OVER MEXICO
PRODUCING NW UPPER FLOW OVER THE W GULF. THIS IS PRODUCING
SCATTERED SHOWERS/THUNDERSTORMS OVER THE W BAY OF CAMPECHE TO
INLAND OVER S MEXICO W OF 94W. AN UPPER HIGH IN THE W ATLC
EXTENDS A RIDGE ACROSS FLORIDA JUST S OF LAKE OKEECHOBEE TO NEAR
25N86W.

CARIBBEAN SEA...
A MID/UPPER LOW HAS DEVELOPED IN THE NW CARIBBEAN NEAR 19N86W
WITH AN UPPER TROUGH EXTENDING E TO SW HAITI NEAR 18N74W WITH
CYCLONIC FLOW N OF 15N N. S OF THE TROUGH IS A MID/UPPER LEVEL
RIDGE EXTENDING FROM THE GULF OF VENEZUELA W TO OVER NICARAGUA
NEAR 12N84W. ISOLATED SHOWERS ARE N OF 18N FROM HAITI TO
JAMAICA...DUE TO THE DIFFLUENCE OF THE TROUGH AND THE UPPER
RIDGE OVER THE W ATLC AND STRAITS OF FLORIDA. THE ITCZ AXIS RUNS
ALONG THE N PORTION OF SOUTH AMERICA AND PANAMA...WITH A SURFACE
LOW INLAND OVER COLOMBIA ARE TOGETHER GENERATING CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION S OF 14N W OF 80W. E
CARIBBEAN IS DOMINATED BY A MID/UPPER LEVEL RIDGE THAT EXTENDS
FROM THE CENTRAL ATLC PRODUCING E TO NE UPPER FLOW E OF 70W.
THIS IS LEAVING THE AREA W OF 71W UNDER MODERATE/STRONG
SUBSIDENCE AND DRY UPPER AIR. ONLY CONVECTION ASSOCIATED WITH
THE TROPICAL WAVE JUST E OF THE LESSER ANTILLES IS PRESENT OVER
THE E CARIBBEAN. MODERATE TRADEWINDS DOMINATE THE ENTIRE
CARIBBEAN.

ATLANTIC OCEAN...
MID/UPPER HIGH IS IN THE W ATLC NEAR 33N73W WITH RIDGE AXIS
EXTENDING SW ACROSS FLORIDA JUST S OF LAKE OKEECHOBEE. THIS IS
BEING PUSHED SW BY A STRONG MID/UPPER LOW JUST E OF THE BAHAMAS
NEAR 27N73W WITH CYCLONIC FLOW WITHIN 200/250 NM RADIUS.
DIFFLUENCE TO THE W IS GENERATING SCATTERED SHOWERS W OF 77W
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS AROUND THE
REMAINDER OF THE UPPER LOW WITHIN 75 NM OF LINE 25N76W-27N71W
AND 29N69W-31N75W. UPPER HIGH IN THE CENTRAL ATLC NEAR 23N60W
EXTENDS A RIDGE AXIS NNW TO NEAR 30N64W. THIS IS ADVECTING
TROPICAL MOISTURE FROM THE CARIBBEAN INTO THE SW ATLC ACROSS
HISPANIOLA. OTHERWISE THE AREA N OF 10N FROM 50W-65W IS UNDER
STRONG SUBSIDENCE AND DRY AIR. THIS IS THE AREA OF DRY AIR IS
ONE OF THE FACTORS IN PREVENTING IRENE FROM FURTHER DEVELOPMENT
AT THIS TIME. MID/UPPER LOW IS OVER THE N CENTRAL ATLC NEAR
32N41W WITH A TROUGH AXIS EXTENDING SW TO JUST NE OF T.S. IRENE.
DUE TO THE DRY UPPER AIR...NO ASSOCIATED SHOWER ACTIVITY CAN BE
GENERATED. THE REMAINDER OF THE ATLC IS DOMINATED BY A MID/UPPER
HIGH LOCATED NEAR 25N24W...THUS SUPPRESSING CONVECTION S OF THE
ITCZ. AT THE SURFACE...SUBTROPICAL RIDGE IS SPLIT BY T.S. HARVEY
AND IRENE WITH A RIDGE OVER THE W ATLC FROM A 1022 MB HIGH NW OF
BERMUDA NEAR 34N67W TO 20N60W AND A RIDGE IN THE E ATLC FROM A
1022 MB HIGH NEAR 32N42W TO 20N33W.

$$
WALLACE



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