305
FXCA20 KWBC 181721
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
121 PM EDT WED OCT 18 2023
FORECAST BULLETIN 18 OCT 2023 AT 1730 UTC: OF NOTE...OFF THE
SOUTHWEST COAST OF MEXICO...THE NATIONAL HURRICANE CENTER IS
FOLLOWING TROPICAL STORM NORMA LOCATED NEAR 14.8N AND 107.9W AT
1500 UTC. IT IS FORECAST TO MOVE NORTHWEST AND TO BECOME A
HURRICANE LATER ON WEDNESDAY. ONSHORE FLOW FROM THE SYSTEM INTO
THE SOUTHERN STATES OF
OAXACA...GUERRERO...MICHOACAN...COLIMA...AND JALISCO IS EXPECTED
TO FAVOR PRECIPITATION ON WEDNESDAY AND MOVE FURTHER NORTH THE
REST OF THE FORECAST PERIOD. THE REST OF THE COUNTRY IS
EXPERIENCING DRIER CONDITIONS AND WILL SEE ISOLATED SHOWERS BUT
LARGE AMOUNTS OF PRECIPITATION ARE NOT EXPECTED. ON
WEDNESDAY...JALISCO...COLIMA...AND MICHOACAN CAN EXPECT MAXIMA OF
20-45MM. GUERRERO AND OAXACA ARE FORECAST MAXIMA OF 15-25MM. ON
THURSDAY...THE AFOREMENTIONED AREAS CAN EXPECT MAXIMA OF 15-25MM.
ON FRIDAY...THE EXTREME SOUTH BAJA CALIFORNIA
SUR...JALISCO...COLIMA...AND GUERRERO CAN EXPECT MAXIMA OF
15-25MM.
OVER THE CARIBBEAN...THE SURFACE FRONTAL SYSTEM REMAINS STATIONARY
AND CONDITIONS TO FAVOR MODERATE AMOUNTS OF PRECIPITATION. THE
STATIONARY FRONT EXTENDS FROM THE CENTRAL ATLANTIC...INTO THE
CENTRAL BAHAMAS...CUBA...AND THE GULF OF HONDURAS. MOISTURE
CONVERGENCE FROM ONSHORE FLOW WILL CONTINUE IN NORTHERN HONDURAS.
WHILE IN THE BAHAMAS...SQUALLY CONDITIONS ARE LIKELY WITH THE
PASSING OF SHORT WAVE TROUGHS ALONG THE DEEP UPPER TROUGH OVER THE
NORTHERN CARIBBEAN. IN ADDITION...A KELVIN WAVE IS EXPECTED OVER
THE REGION OVER THE FORECAST PERIOD ON WEDNESDAY...NORTHERN
HONDURAS CAN EXPECT MAXIMA OF 50-100MM. WHILE ONSHORE FLOW FROM
THE EASTERLY TRADES WILL FAVOR MOISTURE CONVERGENCE IN EASTERN
NICARAGUA...WHERE EXPECT MAXIMA OF 20-45MM. FROM EASTERN EL
SALVADOR...TO WESTERN PANAMA...EXPECT MAXIMA OF 20-35MM. SIMILAR
AMOUNTS ARE FORECAST IN CENTRAL CUBA AND THE CAYMAN ISLANDS. ON
THURSDAY...NORTHERN HONDURAS CAN EXPECT MODERATE AMOUNTS OF
35-70MM...WHILE THE NORTH-CENTRAL BAHAMAS...AND NORTHERN CUBA CAN
EXPECT MAXIMA OF 20-45M...WITH A SLIGHT RISK OF SQUALLY AND SEVERE
WEATHER. THE LEEWARD ISLANDS...COSTA RICA...AND PANAMAS ARE
FORECAST MAXIMA OF 20-35MM. ON FRIDAY...THE DEVELOPMENT OF A LOW
PRESSURE SYSTEM OFF THE EASTERN COAST OF USA WILL FAVOR A COLD
FRONT OVER THE BAHAMAS AND NORTH OF CUBA. A FRONTAL TROUGH
ASSOCIATED WITH THE FRONTAL SYSTEM IS FORECAST OVER CENTRAL CUBA
AND NORTHEAST OF HONDURAS. MODERATE PRECIPITATION IS EXPECTED IN
THE REGION. NORTH-CENTRAL BAHAMAS AND NORTHERN CUBA CAN EXPECT
MAXIMA OF 25-50MM...WITH A RISK OF SQUALLY AND SEVERE WEATHER.
SOUTHERN GUATEMALA...EL SALVADOR...COSTA RICA...AND PANAMA ARE
FORECAST MAXIMA OF 20-45MM...WITH AN INCREASE IN PRECIPITABLE
WATER OFF THE COASTS OF GUATEMALA AND EL SALVADOR...AND ITCZ
INTERACTION IN COSTA RICA AND PANAMA. THE NATIONAL HURRICANE
CENTER IS FOLLOWING A LOW PRESSURE SYSTEM IN THE OPEN ATLANTIC
THAT IS FORECAST TO MOVE CLOSE TO THE LEEWARD ISLANDS BY FRIDAY.
THEY CAN EXPECT MAXIMA OF 30-60MM. THE REST OF THE LEEWARD ISLANDS
AND PARTS OF PUERTO RICO CAN EXPECT MAXIMA OF 20-45MM.
HOWEVER...CONFIDENCE IN THE AMOUNT OF PRECIPITATION IS LOW AS
MODEL GUIDANCE IS NOT IN AGREEMENT. AMOUNTS WILL CHANGE AS
GUIDANCE GAINS MORE CONFIDENCE. ELSEWHERE OVER THE CARIBBEAN BASIN
AND CENTRAL AMERICA...EXPECT ISOLATED MAXIMA BELOW 25MM.
OVER NORTHERN SOUTH AMERICA...INCREASED AMOUNTS OF PRECIPITABLE
WATER IN THE TRADE WINDS ARE FAVORING PRECIPITATION...AND A
MID-UPPER LEVEL TUTT IS RETROGRADING OVER THE EASTERN CARIBBEAN
BASIN WITH ITS BASE OVER NORTHERN VENEZUELA. AREAS OF UPPER
DIVERGENCE OVER THE NEXT SEVERAL DAYS WILL FAVOR MODERATE AMOUNTS
OF PRECIPITATION IN THE REGION. IN ADDITION...A KELVIN WAVE IS
FORECAST TO MAKE ITS WAY OVER THE REGION THROUGHOUT THE FORECAST
PERIOD...ASSISTING IN THE DEVELOPMENT OF DEEP CONVECTION. ON
WEDNESDAY...ONSHORE FLOW OVER WESTERN COLOMBIA AND NORTHWEST
ECUADOR WILL FAVOR MAXIMA OF 35-70MM. EASTERN VENEZUELA AND THE
GUIANAS ARE FORECAST MAXIMA OF 20-45MM. ELSEWHERE...EXPECT
ISOLATED MAXIMA BELOW 25MM. ON THURSDAY...AS THE TUTT CONTINUES
MOVING WEST...AREAS OF UPPER DIVERGENCE WILL ASSIST IN DEEP
CONVECTION OVER NORTHERN COLOMBIA...AND SURFACE TROUGHS IN EASTERN
VENEZUELA WILL FAVOR MODERATE AMOUNTS. ONSHORE FLOW CONTINUES IN
WESTERN COLOMBIA...WITH MAXIMA FORECAST OF 40-80MM. NORTHERN
COLOMBIA CAN EXPECT MAXIMA OF 30-60MM...AND SOUTH-CENTRAL
VENEZUELA...AND WEST GUYANA CAN EXPECT MAXIMA OF 25-50MM. ISOLATED
MAXIMA BELOW 25MM IS EXPECTED ELSEWHERE IN THE REGION.
ACOSTA...WPC (USA)
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