[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 16 2010

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC...

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 38W FROM 7N TO 18N MOVING W NEAR 20 KT.
AN EARLIER ASCAT PASS SHOWED VERY WELL THE WIND SHIFT ASSOCIATED
WITH THE WAVE. SOME CYCLONIC TURNING IS ALSO NOTED ON SATELLITE
IMAGERY ALON THE AXIS NEAR 12N. IN ADDITION...THE WAVE IS
EMBEDDED IN A REGION OF ELEVATED VALUES IN DEEP LAYER MOISTURE
SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE JUST AHEAD OF THE WAVE AXIS.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 48W FROM 7N TO 15N MOVING
W ABOUT 15 KT. A LARGE AREA OF DRY SAHARAN DUST ENCOMPASSES THIS
SYSTEM LIMITING CONVECTION. SCATTERED SHOWERS AND ISOLATED TSTMS
ARE NOTED NEAR THE NORTHERN END OF THE WAVE AXIS.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN ALONG 67W S OF 16N
MOVING W 10-15 KT. THE WAVE IS PRODUCING SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION OVER CENTRAL VENEZUELA. BUOY 42059
LOCATED IN THE EASTERN CARIBBEAN IS REPORTING E WINDS OF 10-15
KT.

...ITCZ...

THE ITCZ AXIS IS ALONG 8N13W 10N26W 11N35 10N44W 10N62W.
OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 160 NM S
OF AXIS E OF 18W TO THE COAST OF WEST AFRICA. SIMILAR CONVECTION
IS ALSO NOTED NEAR 9N26W.

...DISCUSSION...

GULF OF MEXICO...
A MOSTLY DRY AND STABLE AIR MASS REMAINS OVER THE WESTERN HALF
OF THE GULF OF MEXICO COURTESY OF A 1018 MB HIGH LOCATED NEAR
28N93W. HOWEVER...AN AREA OF DEEP LAYERED MOISTURE IS OVER MOST
OF THE EASTERN HALF OF THE GULF INCLUDING ALSO THE FLORIDA
PENINSULA...WESTERN CUBA...AND THE YUCATAN PENINSULA. THIS AREA
OF MOISTURE ALONG WITH A SURFACE TROUGH EXTENDING ALONG 89W S OF
27N TO THE YUCATAN PENINSULA ARE ENHANCING SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE REGION. THE HIGH PRES WILL BE REPLACED
BY A RIDGE ALONG 27N SAT NIGHT WHILE THE TROUGH WILL MOVE TO THE
FAR WESTERN PORTION OF THE GULF BY SAT EVENING WHILE BECOMING
DIFFUSE. NE UPPER-LEVEL WINDS ARE SEEN OVER MUCH OF THE AREA.

CARIBBEAN SEA...
A MOIST AND UNSTABLE AIR MASS DOMINATES MUCH OF THE CARIBBEAN
SEA. CONVECTION CONTINUES TO DEVELOP NEAR THE COLOMBIAN/
PANAMANIAN LOW...ANALYZED 1011 MB NEAR 10N75W ON THE 06Z SURFACE
MAP. SCATTERED TO NUMEROUS MODERATE TO ISOLATED STRONG
CONVECTION IS NOTED FROM 8N-12N BETWEEN 71W-78W. THIS ACTIVITY
IS AFFECTING NORTHERN COLOMBIA AND WESTERN VENEZUELA INCLUDING
THE LAKE MARACAIBO. SHOWERS AND TSTMS ARE ALSO DEVELOPING
OVER THE WESTERN CARIBBEAN IN ASSOCIATION WITH A SURFACE TROUGH
WHICH EXTENDS ALONG 82W/83W FROM 12N TO 18N. A DIFFLUENT PATTERN
ALOFT...BETWEEN AN UPPER-LEVEL HIGH OVER THE EASTERN CARIBBEAN
AND AN UPPER-LEVEL LOW SPINNING OVER EASTERN CUBA...IS ENHANCING
ALL THIS CONVECTIVE ACTIVITY. THE SHOWER ACTIVITY OVER THE NE
CARIBBEAN IS ON INCREASE. THE SAN JUAN DOPPLER RADAR SHOWS
SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED TSTMS OVER THE US/UK
VIRGIN ISLANDS...PUERTO RICO AND COASTAL WATERS. EXPECT MORE
SHOWER AND TSTM ACTIVITY ACROSS THE NE CARIBBEAN THIS WEEKEND AS
AN UPPER-LEVEL LOW FROM THE CENTRAL ATLC MOVES SW TOWARD THAT
REGION.

ATLANTIC OCEAN...
CURRENTLY...THE AFOREMENTIONED UPPER-LEVEL LOW IS HELPING TO
INDUCE CONVECTION BETWEEN CUBA AND THE BAHAMAS AS WELL AS OVER
THE FLORIDA KEYS AND THE STRAITS OF FLORIDA. THE UPPER-LOW WILL
SLOWLY MOVE WWD TODAY AND SAT TOWARD THE SE PORTION OF THE GULF
OF MEXICO INCREASING THE LIKELIHOOD OF SHOWERS AND TSTMS OVER
SOUTH FLORIDA AS THE EASTERN SIDE OF THE UPPER LOW TRANSPORTS
THE MOISTURE NORTHWARD. AN UPPER-LEVEL RIDGE EXTENDS FROM NEAR
BERMUDAS TO HISPANIOLA. ANOTHER UPPER-LEVEL LOW IS OVER THE
CENTRAL ATLC GENERATING A FEW SHOWERS N OF 25N BETWEEN 50W AND
60W. AN UPPER LEVEL TROUGH STRETCHES FROM THIS LOW TO NEAR
16N55W. THE UPPER TROUGH SUPPORTS A SURFACE TROUGH THAT EXTENDS
FROM 22N58W TO THE N LEEWARD ISLANDS NEAR 17N62W. THIS SYSTEM IS
PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS FROM 18N-22N
BETWEEN 55W-65W...MORE CONCENTRATED NEAR THE NORTHERN END OF THE
TROUGH AXIS. AN EARLIER ASCAT PASS INDICATED NE WINDS OF 20 TO
25 KT WITHIN AROUND 240 NM NW OF THE TROUGH AXIS. FARTHER EAST
ACROSS THE ATLANTIC...SURFACE RIDGING DOMINATES THE BASIN
ANCHORED BY A SERIES OF 1025 AND 1026 MB HIGHS CENTERED N OF THE
DISCUSSION AREA. THE STRONGEST ONE IS LOCATED NEAR THE AZORES.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GR






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