[Printable]
Links in the discussion text will open a (small) new browser window with more information inside.
A more complete Weather Glossary is Available Here
000 FXUS62 KKEY 220246 AFDKEY AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS NATIONAL WEATHER SERVICE KEY WEST FL 1046 PM EDT SUN SEP 21 2008 .DISCUSSION... THE KEY WEST RAWINSONDE OBSERVATION THIS EVENING SHOWED A MODERATELY UNSTABLE THERMODYNAMIC STRATIFICATION WITH WEAK CONVECTIVE INHIBITION JUST ABOVE THE CONDENSATION LEVEL WHICH WAS NEAR 2000FT. A VERY MOIST PROFILE WAS EVIDENT IN THE BOUNDARY LAYER...WITH SOME DRIER AIR OBSERVED IN THE 850-925MB LAYER. LATEST RADAR IMAGE LOOPS SHOW ISOLATED DEEP BUT NON-THUNDERING CONVECTIVE CELLS MOVING WESTWARD OVER PORTIONS OF THE SERVICE AREA IN VERY WEAKLY SHEARED SURFACE-TO-600MB EASTERLY FLOW. A LARGE-SCALE ANALYSIS SHOWS THE WESTERN PORTION OF A DEEP BUT WEAK SUBTROPICAL ATLANTIC RIDGE CENTERED OVER SOUTHERN FLORIDA AND THE STRAITS OF FLORIDA. AT THE SURFACE...THE CLOSEST ORGANIZED HIGH PRESSURE CELLS ARE FAR AWAY OVER THE CENTRAL NORTH ATLANTIC AND EASTERN CANADA. THE KEYS ARE LEFT IN A WEAK TO MODERATE EASTERLY TRADE-WIND FLOW. FORECASTS ISSUED BY THE DAY CREW REMAIN VALID AND ON TRACK...AND NO EVENING UPDATES ARE NECESSARY. WEAK SUBSIDENCE ON THE SYNOPTIC SCALE WILL MAINTAIN SLIGHT CONVECTIVE INHIBITION AND DRY AIR AT LOW LEVELS ABOVE THE BOUNDARY LAYER OVERNIGHT. THIS COMBINED WITH A FEW SOURCES OF MESOSCALE SURFACE-BASED LIFT IN THE WEAK EASTERLY FLOW SHOULD KEEP RAIN CHANCES BELOW 30 PERCENT THROUGH 0600 EDT. && .MARINE... GENTLE TO MODERATE EASTERLY BREEZES ARE EXPECTED OVERNIGHT WITH ISOLATED SHOWERS AND PERHAPS A THUNDERSTORM. A SLIGHT NOCTURNAL WIND SURGE MAY AFFECT ATLANTIC ZONES AFTER MIDNIGHT WITH PEAK SUSTAINED EASTERLY WINDS TOPPING OUT NEAR 15KT. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT THE KEYW AND KMTH ISLAND TERMINALS TONIGHT. BRIEF MVFR/IFR VIS AND/OR CIGS WILL BE POSSIBLE WITHIN ANY ISOLATED SHOWERS AND THUNDERSTORMS. SURFACE WINDS WILL AVERAGE FROM 080 TO 100 DEGREES AOA 10 KNOTS. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...NONE. GM...NONE. && $$ PUBLIC/MARINE.........KASPER AVIATION/NOWCASTS.....FUTTERMAN DATA COLLECTION.......WAH VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST