[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI AUG 19 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.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 30W/31W S OF 22N MOVING W 10-15
KT. BROAD ROTATION ACCOMPANIES THIS WAVE WITH LOWER PRESSURES
SUGGESTING THE PRESENCE OF A LOW LEVEL CIRCULATION CENTERED
ALONG THE WAVE NEAR 13N. THE WAVE COULD BEGIN MOVING FASTER NOW
THAT IT IS FARTHER AWAY FROM THE ENHANCING W WINDS OFF THE COAST
OF AFRICA. ASSOCIATED DEEP CONVECTION IS S OF THE ITCZ.

W ATLC WAVE ALONG 58W/59W S OF 17N MOVING W 10-15 KT. WAVE
INVERTED-V SIGNATURE REMAINS STRONG BUT AS THIS WAVE IS AT THE
LEADING EDGE OF DRY AIR AND AFRICAN DUST THERE IS NO ASSOCIATED
DEEP CONVECTION. ISOLATED SHOWERS ARE WITHIN 120 NM OF THE WAVE
AXIS FROM 10N-18N.

W CARIBBEAN WAVE IS ALONG 85W S OF 20N MOVING W 10-15 KT. THE
BROAD MID LEVEL ROTATION REMAINS NEAR 13N82W AS THE WAVE
CONTINUES WESTWARD. WAVE IS BENEATH AN UPPER LOW THAT HAS BEEN
MOVING W ACROSS THE CARIBBEAN THIS WEEK. ANY DEEP CONVECTION IS
TIED TO THE UPPER LOW RATHER THAN AS RESULT OF THE TROPICAL
WAVE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N16W 14N23W 9N34W 7N46W 8N60W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 5N-10N BETWEEN 25W-44W WITH AND FROM 8N-14N E OF 25W TO
JUST INLAND OVER AFRICA.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LOW IS MOVING INLAND OVER SE TEXAS NEAR 28N98W WITH AN
UPPER TROUGH EXTENDING ALONG THE COAST OF MEXICO TO THE W BAY OF
CAMPECHE. LARGE MID/UPPER HIGH IS CENTERED OVER SW GEORGIA WITH
ANTICYCLONIC FLOW DOMINATING THE REMAINDER OF THE GULF. THIS IS
LEAVING MOST OF THE GULF WITH CLEAR SKIES. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS IN THE BAY OF CAMPECHE S
OF 20N FROM 92W-97W AS A RESULT OF DIFFLUENT FLOW OF THE UPPER
TROUGH AND RIDGE. ONLY ISOLATED SHOWERS DOT THE GULF W OF 90W.
AT THE SURFACE...A WEAK 1017 MB HIGH IS IN THE NE GULF NEAR
28N85W. THE UPPER HIGH WILL DOMINATE THE GULF OVER THE NEXT FEW
DAYS AS THE UPPER LOW MOVES ACROSS TEXAS GIVING THE GULF
RELATIVE DRY WEATHER FOR THE WEEKEND EXCEPT IN THE SW WHERE WET
WEATHER ASSOCIATED WITH THE TROPICAL WAVE MOVING IN FROM THE W
CARIBBEAN.

CARIBBEAN SEA...
W CARIBBEAN IS DOMINATED BY AN UPPER LOW CENTERED IN THE GULF OF
HONDURAS NEAR 17N87W WHILE THE E IS DOMINATED BY AN UPPER RIDGE
EXTENDING FROM A HIGH N OF VENEZUELA NEAR 15N69W WITH A RIDGE
EXTENDING N ACROSS HISPANIOLA TO THE TURKS AND CAICOS. THE HIGH
OVER THE W ATLC IS GIVING THE N CARIBBEAN DIFFLUENT FLOW AND
GENERATING SCATTERED SHOWERS/THUNDERSTORMS N OF THE CAYMAN
ISLANDS TO CUBA W OF JAMAICA. DIFFLUENT FLOW BETWEEN THE UPPER
SYSTEMS OF THE CARIBBEAN IS ALSO GENERATING SIMILAR ACTIVITY
FROM 11N-17N BETWEEN 80W-86W. AT THE SURFACE...A TROUGH EXTENDS
FROM THE W/CENTRAL ATLC TO OVER THE VIRGIN ISLANDS...REMNANTS OF
A SURFACE LOW/TROPICAL DEPRESSION TEN...THAT IS GENERATING A
SIGNIFICANT AMOUNT OF SHOWERS AND STRONG THUNDERSTORMS FROM
18N-22N BETWEEN 58W-67W INCLUDING THE N LEEWARD ISLANDS TO
PUERTO RICO. THIS FEATURE WILL CONTINUE MOVING WNW AND BE OVER
THE BAHAMAS BY THE WEEKEND.

ATLANTIC OCEAN...
THE W ATLC IS CHARACTERIZED BY THE TYPICAL RIDGE/TROUGH/RIDGE
SCENARIO WITH AN UPPER HIGH IS CENTERED OVER SW GEORGIA AND
BROAD ANTICYCLONIC FLOW COVERING THE AREA W OF 70W...A CUT-OFF
IS THE THE CENTERED TO THE SE NEAR 26N67W WITH AN UPPER TROUGH
EXTENDING SSW FROM 29N64W TO N OF HISPANIOLA NEAR 22N69W...AND A
SECOND HIGH CENTERED NEAR 26N56W. THIS IS GIVING THE AREA
SURROUNDING THE UPPER LOW/TROUGH UNSETTLED WEATHER. A SURFACE
TROUGH EXTENDS JUST W OF THE UPPER TROUGH FROM 27N66W SW ACROSS
THE TURKS AND CAICOS TO E CUBA NEAR 21N75W WITH SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 150 NM E OF THE TROUGH FROM
22N-27N. A SECOND SURFACE TROUGH EXTENDS FROM 23N63W TO OVER THE
VIRGIN ISLANDS...REMNANTS OF A SURFACE LOW/TROPICAL DEPRESSION
TEN...GIVING THE AREA SHOWERS AND STRONG THUNDERSTORMS FROM
18N-22N BETWEEN 58W-67W. A BROAD MID/UPPER LOW IN THE CENTRAL
ATLC IS CENTERED NEAR 26N43W WITH A TROUGH EXTENDING S TO
18N50W. ALTHOUGH UPPER LEVEL MOISTURE IS BEING ADVECTED S OVER
THE AREA...THE LOWER LEVELS REMAIN DRY...THUS SHOWERS/CONVECTION
CANNOT BE MAINTAINED. THE E ATLC AND DEEP TROPICS ARE DOMINATED
BY AN UPPER RIDGE THAT EXTENDS FROM OFF THE COAST OF SENEGAL
AFRICA NEAR 16N16W ALONG 14N34W NEAR 15N46W. THIS IS LEAVING THE
E ATLC UNDER STRONG SUBSIDENCE AND DRY AIR AND KEEPING
CONVECTION S OF THE ITCZ AXIS.

$$
WALLACE



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