[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071102
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON JUL 07 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 02N25W TO 11N28W MOVING W AT 15-20
KT. DESPITE THE LOW LATITUDE NATURE OF THE WAVE...WITH THE MID-
LEVEL VORTEX BEING NEAR 08N...THE SYSTEM HAS MAINTAINED AN
IMPRESSIVE SATELLITE PRESENTATION WITH DEEP CONVECTION INTACT
SINCE LEAVING WEST AFRICA ABOUT A DAY PREVIOUS. AN EARLIER ASCAT
SCATTEROMETER PASS INDICATED A HIGH AMPLITUDE TROUGH...BUT
WITHOUT A CLOSED CIRCULATION.  SCATTERED MODERATE CONVECTION
EXISTS IN ASSOCIATION WITH THE WAVE WITHIN 60 NM OF THE AXIS
BETWEEN 05N AND 09N.

TROPICAL WAVE EXTENDS FROM 05N45W TO 13N39W MOVING W AT 15-20
KT. A STRONG SAHARAN AIR LAYER SIGNAL IS NOTED ON METEOSAT-9 AND
TOTAL PRECIPITABLE WATER IMAGERY SURROUNDING THE WAVE THAT
CONTINUES TO RESULT IN AN OVERALL LACK OF ANY SIGNIFICANT
CONVECTION AT THIS TIME. DURING THE PAST 24 HOURS...THE WAVE HAS
LIKELY DISPERSED A PORTION OF ITS ENERGY INTO A MID-LATITUDE
AMPLIFIED 700 MB TROUGH WHICH LIES TO THE WEST N OF 12N BETWEEN
40-45W. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THE WAVE AT
THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N81W TO 22N75W MOVING W AT ABOUT 20
KT. THE WAVE CONTINUES TO TRACK ACROSS THE WESTERN CARIBBEAN
THIS EVENING AS A BROAD 700 MB TROUGH WITH ENHANCED TOTAL
PRECIPITABLE WATER EAST OF THE TROUGH AXIS.  ISOLATED MODERATE
CONVECTION IS WITHIN 120 NM OF THE AXIS N OF 19N.

TROPICAL WAVE EXTENDS FROM 11N96W IN THE NORTHEASTERN PACIFIC
OCEAN TO 22N93W MOVING WNW AT 15-20 KT. THE WAVE IS INDISTINCT
AT THE SURFACE AND IN THE TOTAL PRECIPITABLE WATER
IMAGERY...HOWEVER... IT IS STILL PRESENT IN THE SUNY-ALBANY
TROPICAL TROUGH DIAGNOSTICS AT 700 MB.  GIVEN ITS MOTION TO THE
WNW AND MOVING OUT OF THE DEEP TROPICS...ANOTHER OPTION IS TO
CONSIDER THE SYSTEM A TROUGH RATHER THAN A TROPICAL WAVE. THE
WAVE IS CURRENTLY MOVING BENEATH AN UPPER LEVEL SOUTHWESTERLY
FLOW PATTERN THAT REMAINS FAIRLY DIFFLUENT ON THE EASTERN
PERIPHERY OF UPPER-LEVEL LOW CENTERED OVER EAST-CENTRAL MEXICO
NEAR 22N101W. WHILE SUBSTANTIAL DEEP CONVECTION OCCURRED OVER
SOUTHERN MEXICO LATE YESTERDAY...NO SIGNIFICANT DEEP CONVECTION
IS CURRENTLY OCCURRING.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 16N17W TO
07N25W. A BREAK OCCURS IN THE TROUGH IN ASSOCIATION WITH A
TROPICAL WAVE.  THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS
FROM 06N30W TO 04N52W ON THE SOUTH AMERICAN COAST. ASIDE FROM
THE CONVECTION NEAR 27W ASSOCIATED WITH THE WAVE...SCATTERED
MODERATE CONVECTION IS WITHIN 60 NM OF THE ITCZ EAST OF 34W. THE
NORTHEAST PACIFIC MONSOON TROUGH EXTENDS ACROSS CENTRAL AMERICA
AND ENTERS THE CARIBBEAN SEA AT 09N82W AND EXTENDS TO COLOMBIA
AT 10N76W.  SCATTERED MODERATE CONVECTION EXISTS WITHIN 60 NM OF
THE TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
A WEAK 1019 MB HIGH IS LOCATED OVER THE SW GULF OF MEXICO THIS
MORNING AT 21N97W WITH WEAK RIDGING RESIDING ACROSS THE GULF.
THE RESULTING VERY WEAK PRESSURE GRADIENT IS PRODUCING LIGHT TO
GENTLE BREEZE WINDS OVER THE GULF.  AN UPPER-LEVEL LOW CENTERED
OVER EAST-CENTRAL MEXICO NEAR 22N101W INTERACTING WITH THE
AFOREMENTIONED WESTERNMOST TROPICAL WAVE IS HELPING TO PROMOTE
SCATTERED UPPER-LEVEL CLOUDINESS OVER THE SOUTHERN GULF BUT WITH
LITTLE DEEP CONVECTION.  AN UPPER TROUGH OVER THE SOUTHEAST US
IS HELPING TO MAINTAIN A SURFACE TROUGH ALONG THE WEST COAST OF
THE FLORIDA PENINSULA WITH SCATTERED SHOWERS WITHIN 60 NM OF
THE TROUGH.  MOST OF THE GULF IS COVERED BY SUBSTANTIAL LOW-
LEVEL MOISTURE AS DEPICTED BY THE TOTAL PRECIPITABLE WATER
IMAGERY.  ISOLATED CONVECTION OVER THE GULF MAY OCCUR IN THE
NEXT COUPLE OF DAYS...WITH SUBSTANTIAL DEEP CONVECTION OVER
SURROUNDING LAND AREAS DURING THE AFTERNOON DIURNAL MAXIMUM.

CARIBBEAN SEA...
A MODERATE NORTH-SOUTH PRESSURE GRADIENT IS PRODUCING MODERATE
TO FRESH TRADEWINDS ACROSS MOST OF THE CARIBBEAN WITH STRONG
BREEZE CONDITIONS JUST NORTH OF COLOMBIA AS SEEN IN AN EARLIER
ASCAT SCATTEROMETER PASS.  NO SIGNIFICANT DEEP CONVECTION IS
CURRENTLY OCCURRING ACROSS THE CARIBBEAN.  SUBSTANTIAL LOW-LEVEL
MOISTURE IS PRESENT ACROSS THE CENTRAL CARIBBEAN DUE TO THE
TROPICAL WAVE JUST EAST OF 80W.  AS THIS WAVE PROGRESSES
WESTWARD DURING THE NEXT COUPLE OF DAYS...CHANCES FOR DEEP
CONVECTION INCREASES SOME OVER THE WESTERN CARIBBEAN AND
DIMINISHES OVER THE EASTERN CARIBBEAN.  A FAIRLY LARGE SAHARAN
AIR LAYER WILL OVERSPREAD MOST OF THE CARIBBEAN AND SHOULD
SUPPRESS DEEP CONVECTION FOR A FEW DAYS.

...HISPANIOLA...
NO SIGNIFICANT DEEP CONVECTION IS CURRENTLY OCCURRING ACROSS
HISPANIOLA. SUBSTANTIAL LOW-LEVEL MOISTURE IS PRESENT ACROSS THE
CENTRAL CARIBBEAN DUE TO THE TROPICAL WAVE JUST EAST OF 80W.  AS
THIS WAVE PROGRESSES WESTWARD DURING THE NEXT COUPLE OF
DAYS...CHANCES FOR DEEP CONVECTION FOR HISPANIOLA ARE HIGHER
THAN TYPICAL ON MONDAY...BUT THEN DIMINISH ON TUESDAY AND FOR
THE NEXT COUPLE OF DAYS. A FAIRLY LARGE SAHARAN AIR LAYER WILL
OVERSPREAD MOST OF THE CARIBBEAN WITHIN A FEW DAYS AND SUPPRESS
THE USUAL LATE AFTERNOON DEEP CONVECTION OVER LAND.

ATLANTIC OCEAN...
A LARGE BERMUDA-AZORES HIGH EXTENDS ACROSS THE ATLANTIC FROM
38N15W WEST-SOUTHWESTWARD TO 29N75W.  THE EQUATORWARD PRESSURE
GRADIENT IS WEAKER THAN USUAL AND IS PRODUCING E TO NE GENTLE TO
FRESH BREEZE TRADEWINDS ACROSS MOST OF THE TROPICAL ATLANTIC.  A
WEAK MIDDLE TO UPPER-LEVEL SHORTWAVE TROUGH IS NOTED ON WATER
VAPOR IMAGERY JUST OFFSHORE OF NE FLORIDA.  SCATTERED MODERATE
CONVECTION IS OCCURRING N OF 27N W OF 78W.  AN UPPER LEVEL LOW
OVER THE BAHAMAS NEAR 25N73W HAS WIDELY SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS FROM 22-27N AND BETWEEN 68W AND 75W.  A
COUPLE OF WEAK SURFACE TROUGHS ARE PRESENT ALONG 39W AND 50W
NORTH OF 22N...THOUGH NEITHER HAVE ANY DEEP CONVECTION
CURRENTLY.

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

$$
LANDSEA


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