[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUN 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 48W S OF 12N MOVING W NEAR 15-20 KT.
SSMI-DERIVED TPW THAT SHOWS A SURGE OF MOISTURE NORTHWARD IN
THIS AREA. IN ADDITION...GFS MODEL 850 MB LOW-LEVEL VORTICITY
ALSO SUPPORTS THE POSITION OF THE WAVE. SCATTERED MODERATE
CONVECTION IS WITHIN 250 NM W OF THE WAVE AXIS FROM 5N-11N WITH
MOST OF THIS ACTIVITY EMBEDDED WITHIN THE ITCZ.

A TROPICAL WAVE IS ALONG 58W S OF 17N MOVING W 10-15 KT. A WEAK
1011 MB SURFACE LOW HAS DEVELOPED ALONG THE WAVE AXIS NEAR 10N.
SATELLITE IMAGERY SHOWS A CLUSTER OF MODERATE CONVECTION ON THE
NW SIDE OF THE LOW FROM 10N-14N BETWEEN 58W-61W. THIS SYSTEM
SHOWS UP VERY WELL ON THE UW-CIMMS TPW PRODUCT WHERE A HIGH
AMPLITUDE NWD BULGE OF MOISTURE IS OBSERVED. THE WIND SHIFT
ASSOCIATED WITH THIS FEATURE IS CLEARLY DEFINED AGAINST SURFACE
DATA AND A FEW SHIP OBS WITHIN THE AREA. MOISTURE ASSOCIATED
WITH THIS TROPICAL WAVE AND ITS SURFACE LOW WILL AFFECT THE
WINDWARD ISLANDS THROUGH THU. DEVELOPMENT IS NOT EXPECTED AS THE
SYSTEM MOVES ACROSS E VENEZUELA.

A TROPICAL WAVE IS OVER THE SW GULF OF MEXICO...SRN MEXICO AND
GUATEMALA. THE AXIS IS ALONG 91W S OF 24N MOVING WNW NEAR 15 KT.
WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS
DEPICTED ON THE MIMIC-TPW ANIMATION. LAST FEW VISIBLE SATELLITE
IMAGES CONFIRM POSITION OF THE WAVE WITH SLIGHT CYCLONIC TURNING
EVIDENT ACROSS THE SW GULF. SCATTERED SHOWERS AND TSTMS ARE E OF
THE WAVE AXIS ACROSS THE YUCATAN PENINSULA AND GULF WATERS FROM
23N-25N BETWEEN 86W-89W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N15W 4N30W 6N45W 7N49W 9N56W.
THERE ARE SOME INDICATIONS THAT A NEW TROPICAL WAVE IS GETTING
READY TO EMERGE FROM AFRICA. SURFACE WIND DATA ACROSS W AFRICA
SHOWS POSSIBLE WAVE IS E OF DAKAR SENEGAL. SATELLITE IMAGERY
SHOWS AN AREA OF MODERATE TO ISOLATED STRONG CONVECTION FROM
10N-14N BETWEEN 13W-17W. ELSEWHERE...SCATTERED MODERATE TO
STRONG CONVECTION IS WITHIN 150 NM ON EITHER SIDE OF THE AXIS
BETWEEN 18W-33W. ALL OTHER CONVECTION IS IN ASSOCIATION WITH
TROPICAL WAVES...SEE ABOVE.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A 1018 MB SURFACE HIGH IS CENTERED OVER THE W
ATLC NEAR 29N72W EXTENDING A RIDGE OVER MOST OF THE GULF REGION
N OF 25N. UNDER THIS REGIME LIGHT TO MODERATE SE WINDS DOMINATE
THE AREA...BUT WINDS ARE EXPECTED TO GRADUALLY INCREASE THROUGH
FRI ACROSS THE W GULF IN RESPONSE TO A DEVELOPING LOW PRESSURE
SYSTEM OVER CENTRAL PLAINS. TROPICAL WAVE IN THE SW GULF AND
ASSOCIATED MID-UPPER LEVEL ENERGY WILL CONTINUE TO MOVE WNW OVER
THE W GULF PROVIDING SCATTERED SHOWERS AND TSTMS OVER SRN MEXICO
...YUCATAN PENINSULA AND ADJACENT COASTAL WATERS. BROAD UPPER
LEVEL TROUGHING COVERS MUCH OF THE GULF N OF 22N WITH AN UPPER
LEVEL LOW CENTERED NEAR 27N92W AND ALSO ONE IN W ATLC WATERS
OFFSHORE OF NE FLORIDA NEAR 30N80W. THIS WILL CONTINUE TO
PROVIDE AMPLE LIFT FOR SCATTERED SHOWERS AND TSTMS ACROSS THE
GULF E OF 90W THROUGH FRI.

CARIBBEAN...
HIGH PRESSURE N OF THE AREA IS PRODUCING A RELATIVELY WEAK
PRESSURE GRADIENT ACROSS THE ENTIRE CARIBBEAN SEA WITH LIGHT TO
MODERATE TRADE WINDS ACROSS THE BASIN. MOISTURE ASSOCIATED WITH
THE TROPICAL WAVE ALONG 58W WILL CONTINUE TO MOVE ACROSS THE
WINDWARD ISLANDS BRINGING SCATTERED SHOWERS/TSTMS TO THAT REGION
THROUGH THU. ELONGATED UPPER LEVEL RIDGE EXTENDS ACROSS N
VENEZUELA AND N COLOMBIA PROVIDING NEARLY WESTERLY ZONAL UPPER
FLOW ACROSS MUCH OF THE CARIBBEAN SEA AND VERY LITTLE IN THE WAY
OF CONVECTIVE ACTIVITY. ONLY EXCEPTION ARE CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION ACROSS COASTAL COLOMBIA
...PANAMA...COSTA RICA AND NICARAGUA IN THE SW CARIBBEAN.

ATLANTIC...
TWO UPPER-LEVEL LOWS ARE OVER THE W ATLC EMBEDDED WITHIN BROAD
TROUGHING ACROSS THE NRN GULF AND W ATLC. ONE IS MEANDERING E
OFF THE NE COAST OF FLORIDA NEAR 30N80W AND CONTINUES TO ENHANCE
SCATTERED SHOWERS/ISOLATED TSTMS OVER FLORIDA AND THE NW
BAHAMAS. THE SECOND UPPER-LEVEL LOW IS N OF THE VIRGIN ISLANDS
NEAR 23N64W. CYCLONIC FLOW AROUND THIS LOW IS HELPING TO INDUCE
SOME SHOWER ACTIVITY OVER HISPANIOLA...PUERTO RICO...THE UK/US
VIRGIN ISLANDS AND SURROUNDING COASTAL WATERS. AT THE SURFACE A
1018 MB HIGH PREVIOUSLY MENTIONED DOMINATES THE ATLC W OF 60W. A
COLD FRONT EXTENDS E-W ALONG 30N AND CLIPS THE CENTRAL ATLC. A
BROKEN BAND OF LOW/MID CLOUDS IS AHEAD OF THE FRONT N OF 27N
BETWEEN 35W AND 55W. A BROAD UPPER-LEVEL TROUGH OVER THE CENTRAL
ATLANTIC SUPPORTS THIS FRONT. A SURFACE RIDGE ANCHORED ON A HIGH
SITUATED WELL N OF THE AREA IS IN CONTROL OF THE WEATHER PATTERN
OVER THE E ATLC. ZONAL UPPER LEVEL FLOW IS OVER THE E ATLC N OF
20N AND E OF 30W. IN THE TROPICS...AN UPPER LEVEL HIGH IS
CENTERED NEAR 12N39W WITH THE ANTICYCLONIC FLOW REACHING THE
WINDWARD ISLANDS. THIS UPPER FEATURE IS ASSISTING IN THE
DEVELOPMENT OF SHOWERS AND TSTMS RELATED TO THE ABOVE MENTIONED
TROPICAL WAVES. AN INVERTED TROUGH LIES JUST SOUTH OF THE CAPE
VERDE ISLANDS.

$$
HUFFMAN




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