Area Forecast Discussion
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000
FXUS62 KKEY 180850
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
450 AM EDT SAT APR 18 2015

.DISCUSSION...A DEEP TROPOSPHERIC LOW STANDS OUT ON WATER VAPOR
IMAGERY ACROSS THE SOUTHERN ROCKIES. THIS FEATURE IS DRIFTING
EAST (PER LAST EVENING`S MID AND UPPER LEVEL RAOB
ANALYSES)...DRAGGING A MAXIMUM IN THE SUBTROPICAL WESTERLIES ACROSS
OLD MEXICO. THE LATEST ANALYSES FROM CIMSS REVEAL AN ENERGETIC SPOKE
OF ENERGY ROUNDING THE BAJA...BUCKLING THE SUBTROPICAL JET. THE
MIDWEST AND NORTHWESTERN GULF OF MEXICO REMAIN UNDER THE INFLUENCE
OF PDVA...ENHANCED BY A FAN OF DIFFLUENCE ALOFT AND A RICH TAP OF
WESTERN-GULF BOUNDARY LAYER MOISTURE. A SQUASHED VERSION OF THE
SUBTROPICAL RIDGE REMAINS INTACT ACROSS THE WESTERN
CARIBBEAN...SUPPORTING A FRACTURED HIGH PRESSURE SYSTEM ACROSS THE
WESTERN ATLANTIC AND EASTERN GULF OF MEXICO.


.SHORT TERM (TODAY THROUGH MONDAY)...THE LOW ACROSS THE ROCKIES WILL
PHASE WITH THE NORTHERN STREAM TODAY AND TONIGHT. AS THIS SYSTEM
PROGRESSES IN THE WESTERLIES...THE SUBTROPICAL JET WILL INTENSIFY
ACROSS MEXICO. AT THE SAME TIME...THE REGION OF SYNOPTIC FORCING
WILL LOCALIZE AND STRENGTHEN ACROSS THE GULF OF MEXICO. THIS REGION
FAVORED FOR CONVECTION WILL REMAIN WELL TO THE NORTH OF THE FLORIDA
KEYS...FOCUSING OUR ATTENTION ON STEERING FLOW AND MESOSCALE
INTERACTIONS FOR ANY RAIN CHANCES. STEERING FLOW WILL BECOME
SOUTHERLY ON SUNDAY...OPENING UP IDEAS FROM CUBA. HOWEVER...WE FEEL
CUBA WILL BE SUPPRESSED BY A COLLOCATED ANTICYCLONIC STACK. FORECAST
SOUNDINGS FROM CENTRAL AND WESTERN CUBA SUPPORT THIS ASSERTION.
THUS...WE ADVERTISE ONLY A SLIGHT CHANCE OF SHOWERS THROUGH MONDAY.
THERE IS AN OPPORTUNITY FOR A REVERSE CLOUD LINE LATE MONDAY
AFTERNOON...BUT WE DO NOT HAVE ENOUGH CONFIDENCE TO INCREASE POPS
BEYOND 20 PERCENT. TEMPERATURES WILL REMAIN SULTRY...WITH OVERNIGHT
LOWS IN THE UPPER 70S.

&&

.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...A WEAK SURFACE GRADIENT
WILL PREVAIL THROUGH THE LONG TERM. A REVERSE CLOUD LINE APPEARS MORE
LIKELY TUESDAY AND WEDNESDAY AFTERNOONS...ALTHOUGH LOW LEVEL
INHIBITION AND DRY AIR WILL HAVE COMPETING MOTIVES. THE BEST CHANCES
APPEAR TO BE WEDNESDAY. THE SUBTROPICAL ANTICYCLONE WILL RE-AMPLIFY
INTO THE WESTERN CARIBBEAN AND THE GULF OF MEXICO WEDNESDAY NIGHT
THROUGH FRIDAY...GRADUALLY DECREASING RAIN CHANCES ACROSS THE ISLAND
CHAIN...VEERING STEERING FLOWS TO THE WEST-NORTHWEST.

&&

.MARINE...AN ATLANTIC RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS
THE SOUTHERN TIP OF THE FLORIDA PENINSULA TODAY THROUGH SUNDAY
NIGHT. A TROUGH OF LOW PRESSURE WILL STALL OVER SOUTH FLORIDA MONDAY
THROUGH TUESDAY...BEFORE DISSIPATING TUESDAY NIGHT. AN ATLANTIC
RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS CENTRAL FLORIDA WEDNESDAY
AND WEDNESDAY NIGHT.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS
TODAY. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 5 TO 10 TODAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  86  78  85  78 / 10 10 10 20
MARATHON  88  79  88  78 / 10 10 10 20

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&

$$

PUBLIC/MARINE.........CLR
AVIATION/NOWCASTS.....11
DATA COLLECTION.......CHESSER

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