[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUN 28 2014

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

ATLANTIC TROPICAL WAVE ALONG 35W SOUTH OF 15N IS MOVING QUICKLY
WESTWARD NEAR 25 KT DUE TO EASTERLY JET SOUTH OF THE SUBTROPICAL
HIGH. THE WAVE IS MOVING THROUGH A DRY ENVIRONMENT ASSOCIATED TO
SAHARAN AIR COMBINED WITH SUBSIDENT AIR EAST OF THE SUBTROPICAL
HIGH. CONVECTION IS WEST OF THE WAVE AXIS...WITH SHOWERS NOTED
FROM 06N TO 09N BETWEEN 35W AND 42W IN THE VICINITY OF THE ITCZ.

ATLANTIC TROPICAL WAVE ALONG 49W SOUTH OF 16N...MOVING WESTWARD
AT 15 KT. CONVERGENCE ASSOCIATED TO THIS WAVE IS OCCURRING EAST
OF THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS NOTED FROM
7N TO 9N BETWEEN 43W AND 49W IN THE VICINITY OF THE ITCZ.

EASTERN CARIBBEAN TROPICAL WAVE ALONG 65W SOUTH OF 17N...MOVING
WESTWARD AT 15 TO 20 KT. SCATTERED MODERATE CONVECTION IS NOTED
OVER THE WINDWARD ISLANDS AS WELL AS IN THE VICINITY OF THE WAVE
AXIS OVER SOUTH AMERICA.

CARIBBEAN TROPICAL WAVE ALONG 83W SOUTH OF 20N. ITS WESTWARD
PROGRESS HAS SLOWED AND IS MOVING AT 10 KT OR LESS. THERE IS
LIMITED CONVECTION ASSOCIATED TO THIS WAVE. PAPAGAYO GAP WIND
FLOW IS EXPECTED TO INCREASE DURING THE NEXT COUPLE OF DAYS AS
THE WAVE REACHES THE EASTERN NORTH PACIFIC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N17W
TO 9N23W. ITCZ EXTENDS FROM 9N23W TO 6N47W TO THE COAST OF SOUTH
AMERICA NEAR 5N52W. SCATTERED MODERATE CONVECTION FROM 5N TO 9N
BETWEEN 32W AND 49W.

...DISCUSSION...

...THE GULF OF MEXICO...

AN UPPER LEVEL TROUGH EXTENDS ACROSS OKLAHOMA INTO WESTERN
TEXAS. UPPER LEVEL DIVERGENCE ASSOCIATED WITH A SHORT WAVE
TROUGH MOVING ACROSS LOUISIANA IS HELPING MAINTAIN CONVECTION IN
THE NORTHERN GULF S OF LOUISIANA. AN UPPER LEVEL ANTICYCLONE IS
EAST OF THE TROUGH CENTERED OVER NORTHERN FLORIDA. WEAK 1020 MB
HIGH IS CENTERED OVER THE NE GULF OF MEXICO NEAR 29N84W WITH A
RIDGE EXTENDING SE ACROSS FLORIDA. WESTERLY STEERING FLOW S OF
THE RIDGE AXIS HAS HELPED DRIVE DIURNAL CONVECTION OVER FLORIDA
AND DRIFTING OFF THE WEST COAST OF FLORIDA AND THE FLORIDA KEYS.

...THE CARIBBEAN SEA...

BROAD UPPER LEVEL CYCLONIC FLOW PREVAILS ACROSS THE CARIBBEAN
BASIN WITH UPPER LEVEL TROUGHING NOTED IN THE WESTERN CARIBBEAN.
DRY SAHARA-SOURCE AIR MASS CONTINUES OVER THE AREA CHARACTERIZED
BY A STABLE ENVIRONMENT. SHALLOW TRADE WIND CUMULUS...WITH FEW
SHOWERS PREVAIL OVER MUCH OF THE WATERS. ACTIVE CONVECTION IN
THE SW CARIBBEAN IS BEING ENHANCED BY INTERACTION OF THE MONSOON
TROUGH WITH THE SOUTHERN EXTENT OF A TROPICAL WAVE MOVING ACROSS
WESTERN WATERS OUTSIDE THE USUAL REACH OF THE SAHARAN AIR MASS.
THE PRESSURE GRADIENT BETWEEN THE ATLANTIC RIDGE AND THE MONSOON
TROUGH IS MAINTAINING 20-25 KT TRADES IN THE CENTRAL CARIBBEAN
AND 10-20 KT WINDS IN BOTH THE WESTERN AND EASTERN CARIBBEAN.

...HISPANIOLA...

THE DIURNAL CYCLE OF DAYTIME HEATING AND ASSOCIATED CONVECTION
CONTINUES TO WEAKEN OVER HISPANIOLA. SAHARAN AIR MASS WILL MOVE
OVER HISPANIOLA OVER THE NEXT COUPLE OF DAYS AND DEVELOPMENT OF
AFTERNOON CONVECTION SHOULD BE DELAYED...WITH GENERALLY LESS
COVERAGE THAN IS TYPICALLY EXPECTED DURING THE SUMMER MONTHS.

...THE ATLANTIC OCEAN...

UPPER LEVEL TROUGH EXTENDS FROM AN UPPER LEVEL LOW NEAR
30.5N51.5W SOUTHWESTWARD ACROSS THE WESTERN ATLANTIC... TOWARD
HISPANIOLA THEN INTO THE WEST CENTRAL CARIBBEAN. SUBSIDENCE EAST
OF THIS FEATURE IS HELPING TO MAINTAIN THE EASTERN ATLANTIC
SUBTROPICAL HIGH CENTERED NEAR 33N40W. A SURFACE RIDGE EXTENDS
WSW OF THE SUBTROPICAL HIGH ACROSS THE WESTERN ATLANTIC ROUGHLY
ALONG 27/28N. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
NOTED OVER THE BAHAMAS AND WEST OF THE BAHAMAS ISLAND CHAIN
ASSOCIATED TO THE NORTHERN EXTENT OF A TROPICAL WAVE. A DRY
AIRMASS PREVAILS OVER THE TROPICAL ATLANTIC WATERS AND IS
ASSOCIATED TO THE COMBINATION OF SAHARAN AIR AND DRY SUBSIDENT
AIR ON THE EASTERN SIDE OF THE SUBTROPICAL HIGH THAT IS BEING
ADVECTED WESTWARD AROUND THE CIRCULATION OF THE HIGH. THIS IS
LIMITING DEEP CONVECTION TO THE ITCZ AND SOUTHERN EXTENT OF THE
TROPICAL WAVES MENTIONED ABOVE. WINDS OVER THE SW N ATLC WATERS
W OF 65W ARE IN THE 5 TO 10 KT RANGE OVER MUCH OF THE AREA
EXCEPT S OF 22N WHERE WINDS ARE IN THE 10-15 KT RANGE.
TRADEWINDS OVER THE TROPICAL ATLANTIC WATERS ARE IN THE 15-20 KT
RANGE.

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

$$
MUNDELL


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