[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221714
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 22 2015

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1615 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE EASTERN TROPICAL ATLANTIC EXTENDS ALONG
ABOUT 28W FROM 10N-19N MOVING W NEAR 15 KT OVER THE PAST 24
HOURS. THE WAVE HAS A NEGLIGIBLE SURFACE COMPONENT AND IS ONLY
DETECTABLE VIA THE GFS-BASED TROUGH DIAGNOSTICS. THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS NORTH OF
SIGNIFICANT MOISTURE...AS THE WAVE  REMAINS EMBEDDED WITHIN A
DUSTY SAHARAN AIR LAYER LIMITING ANY ASSOCIATED CONVECTION.

TROPICAL WAVE IN THE EASTERN CARIBBEAN EXTENDS ALONG ABOUT 66W
SOUTH OF 20N TO INLAND OVER SOUTH AMERICA MOVING W-NW NEAR 20 KT
OVER THE PAST 24 HOURS. THE WAVE HAS A DISTINCT SURFACE TROUGH
AS SHOWN BY THE ASCAT AND WINDSAT WIND VECTORS. THE WAVE IS ALSO
EVIDENT IN THE LESSER ANTILLES RAWINDSONDES AND THE TOTAL
PRECIPITABLE WATER IMAGERY.  THE WAVE IS INTERACTING WITH A
TROPICAL UPPER TROPOSPHERIC TROUGH NORTH OF THE CARIBBEAN.
SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION ARE FROM 13N-
20 N BETWEEN 60W-67W.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN EXTENDS ALONG ABOUT 78W
SOUTH OF 18N TO INLAND OVER PANAMA MOVING W NEAR 20 KT OVER THE
PAST 24 HOURS. THE WAVE HAS A NEGLIGIBLE SURFACE COMPONENT...BUT
IS OBSERVABLE VIA THE TOTAL PRECIPITABLE WATER IMAGERY AND
CARIBBEAN RAWINDSONDES.  THERE IS NO SIGNIFICANT CONVECTION
ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE IN THE WESTERN CARIBBEAN EXTENDS ALONG ABOUT 84W
SOUTH OF 20N TO OVER CENTRAL AMERICA MOVING W NEAR 20 KT OVER
THE PAST 24 HOURS. THE WAVE IS BECOMING INDISTINCT WITH ALL
METHODS OF DETECTION AND MAY BE MERGING WITH THE WAVE TO ITS
EAST OVER THE CENTRAL CARIBBEAN.  SCATTERED SHOWERS AND ISOLATED
MODERATE CONVECTION ARE SOUTH OF 15N WITHIN 120 NM OF THE WAVE
AXIS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE EASTERN
TROPICAL ATLANTIC NEAR 12N16W TO NEAR 10N27W. THE ITCZ BEGINS AT
10N27W AND CONTINUES TO SOUTH AMERICA AT 05N53W. SCATTERED
MODERATE CONVECTION IS LOCATED FROM 06N TO 10N BETWEEN 13W AND
26W.

...DISCUSSION...

GULF OF MEXICO...
A WEAK SURFACE RIDGE EXTENDS FROM THE STRAITS OF FLORIDA TO THE
TEXAS COAST.  SOUTH OF THE RIDGE LINE WINDS ARE 5-15 KT OUT OF
THE EAST AND NORTH OF THE RIDGE WINDS ARE 5-15 KT OUT OF THE
WEST.  SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION IS
OCCURRING NORTH OF 28N EAST OF 90W. LITTLE CHANGE IS EXPECTED
DURING THE NEXT TWO DAYS.

CARIBBEAN SEA...
A MODERATE PRESSURE GRADIENT PRODUCED BY THE BERMUDA HIGH OVER
THE SUBTROPICAL ATLANTIC AND LOW PRESSURE OVER SOUTHERN CENTRAL
AMERICA AND COLOMBIA IS FORCING EASTERLY TRADEWINDS OF GENERALLY
10-20 KT WITH SOME 25 KT WINDS JUST NORTH OF COLOMBIA.  SOME
CONVECTION IS OCCURRING IN ASSOCIATION WITH THE TROPICAL
WAVES...AS DESCRIBED ABOVE.  THE REMAINDER OF THE CARIBBEAN HAS
MOSTLY CLEAR SKIES CURRENTLY. THE PRESSURE GRADIENT WILL TIGHTEN
SLIGHTLY BY FRIDAY...BOOSTING SOMEWHAT THE WINDS ACROSS THE
CARIBBEAN.

...HISPANIOLA...
NO SIGNIFICANT SHOWER ACTIVITY IS OCCURRING CURRENTLY OVER
HISPANIOLA.  HOWEVER...AS THE TROPICAL WAVE OVER THE EASTERN
CARIBBEAN APPROACHES THE ISLAND INCREASED MOISTURE AND
INSTABILITY SHOULD ENHANCE CHANCES FOR SHOWERS AND DEEP
CONVECTION LATER TODAY AND AGAIN ON THURSDAY AFTERNOON.  BY
FRIDAY...THE TROPICAL WAVE AND THE ADDITIONAL MOISTURE SHOULD BE
WEST OF HISPANIOLA...REDUCING PRECIPITATION POTENTIAL THEN.

ATLANTIC OCEAN...
A 1023 MB BERMUDA HIGH CENTERED NEAR 29N47W AND A 1025 MB AZORES
HIGH CENTERED NEAR 32N32W ARE DOMINATING CONDITIONS ACROSS THE
SUBTROPICAL NORTH ATLANTIC.  THE MODERATE PRESSURE GRADIENT
SOUTH OF THE HIGHS ARE PRODUCING NORTHEAST TRADEWINDS OF 10-15
KT EAST OF ABOUT 55W AND SOUTHEAST TRADEWINDS OF 10-15 KT FROM
ABOUT 55W-70W.  A WEAK TROUGH OF LOW PRESSURE IS EAST OF FLORIDA
EXTENDING FROM 26N80W TO 30N76W.  SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION EXISTS WITHIN 60 NM OF THE TROUGH
NORTH OF 27N.  SURFACE WINDS WEST OF 70W ARE GENERALLY SW AT 10-
20 KT.  ISOLATED MODERATE CONVECTION EXISTS FROM 24N-27N BETWEEN
45W-48W DUE TO AN UPPER LEVEL LOW.  NO SIGNIFICANT CHANGES ARE
EXPECTED TO THE WINDS DURING THE NEXT TWO DAYS.

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

$$
LANDSEA
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