Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KKEY 171853
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
250 PM EDT WED SEP 17 2014

.DISCUSSION...
.CURRENTLY...
SKIES ARE PARTLY TO MOSTLY SUNNY WITH EPISODIC...ALBEIT FEEBLE CLOUD
LINES ACROSS THE ISLAND CHAIN. MEANWHILE...LOCAL RADARS ARE
DETECTING A FEW SHOWERS ALONG THE FLORIDA KEYS AND THE ADJACENT
NEARSHORE WATERS...WITH ISOLATED SHOWERS ON THE OUTER WATERS OF
MAINLAND MONROE. SURFACE WISE...A RIDGE AXIS IS ALIGNED ACROSS OUR
COUNTY WARNING AREA...WITH VARIABLE WINDS OF LESS THAN 5 KNOTS
INDICATED BY C-MAN STATION PLATFORM OBSERVATIONS AND A 15Z ASCAT
PASS.

.SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...
AN UNSEASONABLY DEEP CYCLONIC FLOW DIGGING DOWN INTO THE FLORIDA
PENINSULA WILL RESULT AN INCREASINGLY CONFLUENT...MOIST AND UNSTABLE
AIRMASS IN OUR REGION OVER THE NEXT SEVERAL DAYS. DUE TO THE CLOSE
PROXIMITY OF THE APPROACHING LOW LEVEL CONVERGENT BOUNDARY...WILL
RAISE POPS TO 40 PERCENT BEGINNING THURSDAY...AND INSERT HIGH CHANCE
POPS BEGINNING FRIDAY NIGHT. ALSO...CONSIDERABLE MID AND HIGH
CLOUDINESS WILL SPILL INTO OUR AREA FROM PLENTY OF DEEP CONVECTION
TO OUR NORTH. HENCE...HIGH TEMPERATURES WILL RANGE BETWEEN 85 AND 90
DEGREES..WITH OVERNIGHT LOWS BETWEEN 75 AND 80 DEGREES TO ACCOUNT
FOR CLOUDINESS...RAINFALL AND RADIATIONAL COOLING.

.LONG TERM (SUNDAY THROUGH WEDNESDAY)...
WITH MEDIUM RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT WITH THE TROUGH
DEPARTING THE FLORIDA PENINSULA AND THE EXTREME SOUTHEAST UNITED
STATES...THE SUBTROPICAL RIDGE WILL SLOWLY BUILD WESTWARD AND ACROSS
EXTREME SOUTH FLORIDA AND OUR REGION. THEREFORE...HAVE MAINTAINED 40
PERCENT POPS FOR THE END OF THIS WEEKEND AND LOW CHANCE POPS DUE TO
A DEEPENING EASTERLY FLOW THEREAFTER.

&&

.MARINE...
AWAY FROM SHOWERS AND THUNDERSTORMS...VARIABLE WINDS OF LESS THAN 10
KNOTS WILL PERSIST ON ALL KEYS COASTAL WATERS THROUGH AT LEAST
FRIDAY...BEFORE WINDS BECOME PREDOMINATELY EAST AND INCREASE
SLIGHTLY FRIDAY NIGHT AND THIS WEEKEND.

&&

.AVIATION...
VFR WILL PREVAIL AT BOTH THE KEY WEST AND MARATHON TERMINALS WITH
MOSTLY WEST TO NORTHWEST WINDS AROUND 5 KNOTS. CLOUD LINES MAY FORM
ALONG THE ISLAND CHAIN BUT DRIFT TO THE LEE...SOUTH SIDE...OF THIS
AFTERNOON DUE TO WEAK WEST TO NORTHWEST STEERING FLOW. THESE CLOUD
LINES MAY PROVIDE VICINITY SHOWER BASED NEAR 025...RESULTING IN
TEMPORARY MVFR EPISODES.

&&

.CLIMATE...SEPTEMBER 17TH...ON THIS DATE IN FLORIDA KEYS CLIMATE
HISTORY...IN 1985...THE DAILY RECORD LOW TEMPERATURE OF 69F WAS
RECORDED. THIS IS ALSO TIED FOR THE COLDEST TEMPERATURE EVER
RECORDED IN SEPTEMBER. TEMPERATURE RECORDS IN KEY WEST HAVE BEEN
KEPT SINCE 1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  80 87 81 87 / 30 40 40 40
MARATHON  79 99 80 99 / 30 40 40 40

&&

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

&&

$$

PUBLIC/MARINE/FIRE/CLIMATE/DIGITAL...APA
AVIATION/NOWCASTS....................BWC
DATA ACQUISITION.....................BF

VISIT US ON THE WEB AT WEATHER.GOV/KEY

FOLLOW US ON FACEBOOK AND TWITTER AT...

WWW.FACEBOOK.COM/NWSKEYWEST
WWW.TWITTER.COM/NWSKEYWEST

















USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.