Prognostic Meteorological Discussion
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
235 PM EDT MON JUN 26 2017

AT 15 UTC HURRICANE DORA CENTERED NEAR 17.3N 106.3W...WITH MAXIMUM
SUSTAINED WINDS OF 75KT AND MINIMAL CENTRAL PRESSURE OF 985 HPA.
THE HURRICANE IS MOVING TO THE WEST-NORTHWEST AT 11KT. SEE NHC
BULLETIN FOR DETAILS.

TROPICAL DISCUSSION FROM JUNE 26/12 UTC: A 250 HPA HIGH TO THE
WEST-SOUTHWEST OF MICHOACAN MEXICO ANCHORS A RIDGE THAT EXTENDS
OVER MEXICO TO THE GULF. THE RIDGE ALOFT IS VENTING DEEP
CONVECTION IN ASSOCIATION WITH HURRICANE DORA. ALTHOUGH THE MOST
ACTIVE CONVECTION WITH THIS CYCLONE IS EXPECTED OVER THE EASTERN
PACIFIC...IT IS TO ALSO FAVOR SCATTERED CONVECTION ACROSS
SOUTHWEST MEXICO...TO TRIGGER RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-40MM THROUGH TUESDAY MORNING. ON TUESDAY THIS
DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE ON
WEDNESDAY THE MAXIMA IS TO INCREASE TO 20-35MM. OTHER CONVECTION
IS TO CLUSTER ALONG THE SIERRA MADRE OCCIDENTAL BETWEEN
SONORA-SINALOA...WITH ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF
15MM.

A SHORT WAVE TROUGH ON THE SOUTHERN STREAM IS TO THEN PRESS
AGAINST BROAD CELL OF THE SUBTROPICAL RIDGE OVER MEXICO. UNDER
INFLUENCE OF SUCCESSIVE SHORT WAVE VORTICES THE MID/UPPER LEVEL
TROUGH IS FORECAST TO GRADUALLY DEEPEN THROUGH WEDNESDAY EVENING.
AT LOW LEVELS...THERMAL TROUGH OVER WESTERN MEXICO WILL FAVOR A
MOIST EASTERLY FLOW ACROSS THE GULF TO THE EASTERN STATES OF
MEXICO. THIS WILL COMBINE WITH STRONG TOPOGRAPHICAL FORCING ALONG
THE SIERRA MADRE ORIENTAL TO SUSTAIN AREAS OF MODERATE TO HEAVY
CONVECTION. INITIALLY MOST ACTIVE IS TO CLUSTER ACROSS
VERACRUZ...WITH ACCUMULATION OF 15-20MM/DAY AND MAXIMA OF 35-70MM.
ON TUESDAY THE CONVECTION IS TO BUILD NORTH ACROSS TAMAULIPAS...TO
SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM...WHILE OVER COAHUILA THIS IS TO TRIGGER RAINFALL AMOUNTS
OF 05-10MM/DAY AND MAXIMA OF 15MM. ON WEDNESDAY...SCATTERED DEEP
CONVECTION IS TO AFFECT CENTRAL MEXICO WITH ACCUMULATION OF
10-15MM/DAY AND MAXIMA OF 20-35MM.

A TUTT LOW TO THE EAST...WITH CLOSED CIRCULATION NEAR 29N
54W...EXTENDS A TROUGH TO THE WEST-SOUTHWEST ACROSS THE
BAHAMAS-CUBA TO THE WESTERN CARIBBEAN. UPPER LEVEL TROUGH IS TO
REMAIN CUT OFF FROM THE FLOW...AND AS SUCH IT IS TO GRADUALLY
WEAKEN THROUGH THURSDAY MORNING. AT 500 HPA...A DUAL BARRELED CELL
OF THE SUBTROPICAL RIDGE DOMINATES THE FLOW ACROSS THE NORTHERN
CARIBBEAN ISLES/SOUTHWEST ATLANTIC TO THE EASTERN GULF OF MEXICO.
MID LEVEL RIDGE PATTERN IS FORECAST TO PERSIST DURING THE NEXT FEW
DAYS. ACROSS CUBA AND HISPANIOLA THIS WILL BE STRONG ENOUGH TO
DELAY...BUT NOT SUPPRESS...THE ONSET OF DIURNAL CONVECTION. ACROSS
CUBA THE TUTT ALOFT IS TO THEN ENHANCE LATE AFTERNOON CONVECTION.
INITIALLY THIS WILL FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. THROUGH WEDNESDAY...AS THE TUTT WEAKENS...THE
DAILY MAXIMA DECREASES TO 15MM. ACROSS HISPANIOLA INITIALLY
EXPECTING ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM AS
ENHANCED BY A TROPICAL WAVE TO THE SOUTH. THROUGH
TUESDAY-WEDNESDAY THIS DECREASES TO 05-10MM/DAY AND MAXIMA OF
15MM. OVER PUERTO RICO MOST ACTIVE IS TO CLUSTER ON WESTERN
PORTIONS OF THE ISLAND...WITH ACCUMULATION OF 05-10MM/DAY AND
MAXIMA OF 15MM. SIMILAR AMOUNTS ARE EXPECTED OVER JAMAICA OVER THE
NEXT FEW DAYS.

CELL OF THE SUBEQUATORIAL RIDGE LIES TO THE SOUTH...EXTENDING
EAST-TO-WEST ACROSS THE TROPICAL ATLANTIC-ISLAND CHAIN TO THE
CARIBBEAN. THIS IS TO GENERALLY PERSIST DURING THE NEXT FEW DAYS.
MEANWHILE...THE RIDGE ALOFT IS TO VENT DEEP CONVECTION ACROSS
EQUATORIAL SOUTH AMERICA. MOST ACTIVE IS TO CLUSTER ALONG THE
ITCZ/NEAR EQUATORIAL TROUGH. ACROSS EASTERN COLOMBIA-SOUTHERN
VENEZUELA AND THE GUIANAS INITIALLY EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM. THROUGH WEDNESDAY THIS
INCREASES TO 20-30MM/DAY AND MAXIMA OF 40-80MM AS ENHANCED BY
STRONG TROPICAL WAVES PULLING ALONG THE NET/ITCZ. ACROSS WESTERN
COLOMBIA INITIALLY EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND
MAXIMA OF 30-60MM. THIS GRADUALLY DECREASES TO 05-10MM/DAY AND
MAXIMA OF 15-25MM.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:
INITIAL   24     36     48     60     72     84     96       TYPE
37W      40W    43W    46W    48W    51W    53W     55W      TW
47W      50W    54W    58W    62W    66W    70W     73W      TW
67W      69W    71W    73W    76W    78W    81W     83W      EW
72W      75W    79W    83W    87W    90W    92W     95W      TW
83W      85W    87W    89W    92W    95W    98W    100W TUTT INDCD

TROPICAL WAVE ALONG 37W REACHES EASTERN FRENCH GUIANA/AMAPA IN
BRASIL EARLY ON THURSDAY MORNING...TO TRIGGER RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. A DRY SAHARAN AIR LAYER TRAILS
THIS WAVE....AND ON ITS WAKE DRY AND DUSTY CONDITIONS WILL
PREVAIL.

TROPICAL WAVE ALONG 47W ENTERS FRENCH GUIANA LATER TODAY...TO
QUICKLY MOVE ACROSS SURINAME TO GUYANA EARLY ON TUESDAY. IN
INTERACTION WITH THE ITCZ THIS WAVE WILL THEN SUSTAIN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. OVER GUYANA TO
EASTERN VENEZUELA THIS IS TO ALSO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM...WHILE OVER NORTHEAST
VENEZUELA-TRINIDAD AND TOBAGO EXPECTING RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM. AS IT APPROACHES THE ISLAND
CHAIN... MOST ACTIVE CONVECTION WITH THIS FEATURE IS EXPECTED WEST
OF THE WAVE AXIS (PRECEDING WAVE PASSAGE). OVER THE
FRENCH/WINDWARD ISLES THIS IS TO THEN FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-30MM EARLY ON WEDNESDAY MORNING.
DURING THE DAY THE FOCUS OF THE HEAVY CONVECTION SHIFTS TO
BARBADOS-FRENCH ISLES WHERE IT IS TO SUSTAIN RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 30-60MM. OVER THE NORTHERN
LEEWARD/VIRGIN ISLES THIS IS TO THEN TRIGGER RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. ACROSS VENEZUELA TO EASTERN
COLOMBIA EXPECTING ACCUMULATION OF 20-30MM/DAY AND MAXIMA OF
40-80MM ON WEDNESDAY TO THURSDAY...WHILE ACROSS WESTERN COLOMBIA
IT IS TO TRIGGER RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
25-50MM ON THURSDAY TO FRIDAY.

AN EASTERLY WAVE ALONG 67W IS TO INTERACT WITH THE NEAR EQUATORIAL
TROUGH AS IT PULLS ACROSS VENEZUELA TO COLOMBIA...TO TRIGGER
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. AS IT PULLS
ACROSS WESTERN COLOMBIA EARLY ON WEDNESDAY MORNING THIS IS TO THEN
SUSTAIN RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM.
ACROSS PANAMA TO COSTA RICA THIS IS TO THEN TRIGGER RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE OVER EASTERN
NICARAGUA EXPECTING ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF
20-40MM ON THURSDAY TO FRIDAY.

A TRADE WINDS SURGE ACCOMPANIES THE TROPICAL WAVE ALONG 72W. UNDER
INFLUENCE OF THIS WAVE AND THE TRAILING WIND SURGE...EXPECTING
SCATTERED CONVECTION ACROSS HISPANIOLA TO TRIGGER RAINFALL AMOUNTS
OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ACROSS JAMAICA IT IS TO
TRIGGER RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. HIGHER
AMOUNTS ARE EXPECTED OVER NORTHERN/NORTHWEST COLOMBIA-THE DARIEN
IN PANAMA...WHERE THIS IS TO FAVOR RAINFALL AMOUNTS OF 15-20MM/DAY
AND MAXIMA OF 30-60MM THROUGH TUESDAY MORNING. ACROSS WESTERN
PANAMA TO COSTA RICA THIS IS TO THEN SUSTAIN RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 35-70MM ON TUESDAY TO WEDNESDAY... WHILE
OVER EASTERN NICARAGUA/NORTHEAST HONDURAS EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. ACROSS HONDURAS/EL
SALVADOR TO GUATEMALA THIS IS TO ALSO TRIGGER RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM ON WEDNESDAY...WHILE OVER
BELIZE-YUCATAN-SOUTHERN MEXICO EXPECT ACCUMULATION OF 05-10MM/DAY
AND MAXIMA OF 15MM.

THE TUTT OVER THE WESTERN CARIBBEAN SUSTAINS AN INDUCED TROUGH IN
THE EASTERLY TRADES WITH AXIS ALONG 83W THAT DECOUPLES FROM THE
UPPER LEVEL PERTURBATION. OVER NICARAGUA-NORTHEAST HONDURAS THIS
IS TO TRIGGER RAINFALL AMOUNTS OF 20-30MM/DAY AND MAXIMA OF
40-80MM...WHILE OVER COSTA RICA EXPECT RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-25MM. OVER EL SALVADOR/WESTERN
HONDURAS TO BELIZE/GUATEMALA-CHIAPAS IN SOUTHERN MEXICO THIS IS TO
THEN SUSTAIN RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM
ON TUESDAY-WEDNESDAY. OVER CENTRAL MEXICO EXPECTING ACCUMULATION
OF 10-15MM/DAY AND MAXIMA OF 20-35MM ON WEDNESDAY...INCREASING TO
10-15MM/DAY AND MAXIMA OF 20-40MM ON THURSDAY.

GAJADHAR...SLMS (SAINT LUCIA)
GALVEZ/DAVISON...WPC (USA)
$$





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