[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171039
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE WAS RE-INTRODUCED TO THE ANALYSIS THIS MORNING.
THIS WAVE HAS AN AXIS THAT EXTENDS FROM 17N37W TO A 1011 MB LOW
CENTERED NEAR 10N37W. THESE FEATURES ARE INTERACTING WITH EACH
OTHER AND CURRENT GUIDANCE SHOW THE LOW DISSIPATING WITHIN THE
NEXT 48 HOURS LEAVING THE WAVE MOVING BY ITSELF ACROSS THE
CENTRAL ATLANTIC AND E CARIBBEAN. TPW IMAGERY DEPICTS A HIGH
MOISTURE CONTENT MAINLY E OF THE WAVE AXIS BETWEEN 03N-16N.
SCATTERED MODERATE CONVECTION IS OBSERVED FROM 03N-15N BETWEEN
29W-39W.

A TROPICAL WAVE IS OVER THE W CARIBBEAN WITH AXIS APPROXIMATELY
ALONG 77W AND FROM 10N TO 19N...MOVING W AT 20-25 KT DURING THE
LAST 24 HOURS. SSMI TPW IMAGERY DEPICT A MODERATE MOIST AIRMASS
ASSOCIATED WITH THIS WAVE PREVAILING ACROSS THE NORTHERN PORTION
OF THE WAVE AND EXTENDING ACROSS THE E CARIBBEAN MAINLY N OF
14N. SAHARAN DUST AND STRONG DEEP-LAYER WIND SHEAR ARE ALSO
PREVAILING ACROSS THIS AREA THUS NO SIGNIFICANT CONVECTION IS
OBSERVED AT THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N16W TO
A 1011 MB SURFACE LOW CENTERED NEAR 10N37W TO 08N47W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N47W TO
06N57W. SCATTERED MODERATE CONVECTION IS OBSERVED SURROUNDING
THE LOW FROM 03N-15N BETWEEN 29W-39W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD SURFACE RIDGE COVERING A GREAT PORTION OF THE ATLANTIC
BASIN EXTENDS W REACHING THE GULF WATERS AND ANCHORED BY A 1018
MB HIGH NEAR 25N86W. ALOFT...AN UPPER-LEVEL LOW IS OBSERVED
CENTERED OVER SOUTHERN MEXICO AND EXTENDING EASTWARD ACROSS THE
BAY OF CAMPECHE BRINGING MOISTURE FROM THE EPAC INTO THE W GULF.
WITH THIS...ISOLATED CONVECTION IS DEVELOPING ACROSS THE SW GULF
MAINLY W OF 94W. A BROAD UPPER-LEVEL HIGH IS CENTERED NEAR
29N90W AND EXTENDING ACROSS THE NORTHERN HALF OF THE GULF. THIS
FEATURE COMBINED WITH THE UPPER-LEVEL LOW OVER THE W CARIBBEAN
GENERATES A DIFFLUENT FLOW ACROSS THE E PORTION OF THE BASIN
SUPPORTING ISOLATED CONVECTION E OF 86W. SCATTEROMETER DATA
DEPICTS A LIGHT ANTICYCLONIC FLOW ACROSS MOST OF THE BASIN
EXCEPT N OF THE YUCATAN PENINSULA S OF 24N BETWEEN 88W-91W WHERE
LIGHT TO GENTLE FLOW IS OBSERVED. EXPECT FOR THE RIDGE TO REMAIN
NEARLY STATIONARY THROUGH THE NEXT 24 HOURS ACROSS THE BASIN
AND WITH A SIMILAR WEATHER PATTERN PREVAILING.

CARIBBEAN SEA...

A TROPICAL WAVE IS MOVING ACROSS THE W CARIBBEAN. PLEASE REFER
TO THE SECTION ABOVE FOR MORE DETAILS. AN AREA OF MODERATE
MOISTURE PREVAILS ACROSS THE NE AND CENTRAL CARIBBEAN N OF 14N
AND E OF 73W. THIS MOISTURE ALONG WITH AN UPPER-LEVEL LOW
CENTERED NE OF THE LEEWARD ISLANDS IS SUPPORTING ISOLATED
MODERATE CONVECTION ACROSS THE MONA PASSAGE AND HISPANIOLA AS
WELL AS THE ADJACENT WATERS N OF 17N BETWEEN 68W-72W. ANOTHER
AREA OF MODERATE MOISTURE PREVAILS ACROSS THE W CARIBBEAN W OF
78W AND WITH SUPPORT OF AN UPPER-LEVEL LOW CENTERED OVER W
CUBA...ISOLATED SHOWERS PREVAIL N OF 15N AND W OF 75W. OVER THE
SW CARIBBEAN...THE PROXIMITY OF THE MONSOON TROUGH S OF PANAMA
AND A SURFACE LOW OVER NE COLOMBIA ARE PRODUCING SCATTERED
MODERATE CONVECTION THAT IS MOVING OVER THE SOUTHERN CARIBBEAN
WATERS MAINLY S OF 10N. A STRONG DEEP LAYER WIND SHEAR AND DRY
AIR CONTINUES TO INHIBIT CONVECTION ELSEWHERE. A GENERALLY TIGHT
PRESSURE GRADIENT BETWEEN THE RIDGE OVER THE ATLANTIC EXTENDING
ACROSS THE NORTHERN BASIN AND LOWER PRESSURES OVER COLOMBIA AND
SOUTH AMERICA SUPPORTS GENTLE TO MODERATE TRADES ACROSS MOST OF
THE BASIN EXCEPT N OF 18N AND W OF 73W WHERE A LIGHT EASTERLY
FLOW PREVAILS. OVER THE NEXT 24 HOURS...EXPECT FOR THE TROPICAL
WAVE TO CONTINUE MOVING W ACROSS THE W CARIBBEAN WITH AN
INCREASE IN MOISTURE. A SIMILAR WEATHER PATTERN WILL PREVAIL
ACROSS THE BASIN.

...HISPANIOLA...

THE MOISTURE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE WITH
AXIS S OF THE ISLAND NEAR 74W COMBINED THE PROXIMITY OF AN UPPER
LEVEL LOW CURRENTLY OVER W CUBA SUPPORTS ISOLATED MODERATE
CONVECTION ACROSS THE ISLAND. SIMILAR ACTIVITY IS POSSIBLE OVER
THE NEXT 24 HOURS.

ATLANTIC OCEAN...

AN UPPER-LEVEL TROUGH PREVAILS OVER THE W ATLANTIC WITH BASE N
OF OUR AREA AND SUPPORTING A STATIONARY FRONT THAT IS CURRENTLY
GENERATING SCATTERED MODERATE CONVECTION N OF 29N AND W OF 68W.
AN UPPER-LEVEL LOW CENTERED OVER W CUBA EXTENDS ACROSS THE
BAHAMAS SUPPORTING ISOLATED CONVECTION S OF 25N AND W OF 76W.
ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 20N61W. ISOLATED
CONVECTION IS DEVELOPING IN THE NORTHERN PERIPHERY OF THIS LOW
FROM 22N-27N BETWEEN 48W-60W. THE CENTRAL AND E ATLANTIC IS
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB
HIGH CENTERED NEAR 28N63W AND A 1021 MB HIGH CENTERED NEAR
33N28W. A WEAKNESS BETWEEN THESE TWO HIGHS IS ANALYZED AS A
SURFACE TROUGH FROM 27N51W TO 31N44W. OVER THE NEXT 24
HOURS...EXPECT FOR THE SURFACE RIDGE TO PREVAIL ACROSS THE BASIN
WITH FAIR WEATHER.

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

$$

ERA
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