Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 05/11/08

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
855 PM PDT SAT MAY 10 2008 .SHORT TERM (TONIGHT-TUESDAY)... SKIES REMAIN CLEAR ACROSS THE CWA THIS EVENING AND TEMPERATURES WARMED UP A FEW DEGREES ALONG THE COASTAL AREAS AND UP 10 TO 15 DEGREES IN MANY PORTIONS OF THE VALLEYS...ANTELOPE VALLEY AND THE LOWER MOUNTAIN ELEVATIONS. THIS WAS DUE TO A WEAK RIDGE ALOFT AND WEAKER ONSHORE GRADIENT WHICH CAUSED STRATUS TO BURN OFF MORE QUICKLY TODAY COMPARED TO YESTERDAY. THERE WERE ALSO SOME LIGHT EASTERLY WINDS ALOFT ABOVE 3000 FT THAT HELPED WARMED THE INLAND AREAS. IN FACT...LANCASTER AND PALMDALE INDICATED LIGHT EASTERLY WINDS MOST OF THE DAY. THIS TEMPORARY WARMTH WILL CHANGE OVERNIGHT INTO SUNDAY AS A TROF BEGINS TO DIVE DOWN INTO OREGON CAUSING THICKNESS AND HEIGHTS TO LOWER A BIT. NAM-WRF INDICATES LAX-DAG SURFACE GRADIENT TO STRENGTHEN TO NEAR +10MB BY TOMORROW AFTERNOON. CURRENT ACARS SOUNDING IS INDICATING A DOUBLE INVERSION AT THIS TIME. ONE NEAR 2000 FT AND ANOTHER NEAR 3000 FT. FOR AREAS S OF POINT CONCEPTION...A CATALINA EDDY WILL DEVELOP OVERNIGHT AND THIS SHOULD HELP WEAKEN THE INVERSION BUT DEEPEN TO 4000 FT BY SUNDAY MORNING. LOW CLOUDS ARE CURRENTLY DEVELOPING ACROSS SAN DIEGO COUNTY COASTAL AREAS...AND SHOULD MOVE NORTH INTO LA AND VENTURA COUNTIES BEFORE MIDNIGHT. LOW CLOUDS WILL QUICKLY PUSH INLAND TO THE COASTAL SLOPES OF THE FOOTHILLS INCLUDING SOUTHERN SANTA BARBARA COUNTY BY EARLY MORNING. LOW CLOUDS SHOULD LINGER THROUGH THE EARLY AFTERNOON HOURS...AND WITH STRONG ONSHORE GRADIENTS...THERE COULD BE A REVERSE CLEARING SCENARIO WITH SOME CLOUDS LINGERING NEAR THE LA/VTU COUNTY VALLEYS AND ADJACENT FOOTHILLS THROUGH MUCH OF THE AFTERNOON. TEMPERATURES WILL BE MUCH COOLER INLAND...EXCEPT THE ANTELOPE VALLEY SHOULD REMAIN IN THE LOWER 80S. SOME LOCALLY GUSTY WINDS WILL BE LIKELY IN THE ANTELOPE VALLEY SUNDAY...BUT SHOULD REMAIN BELOW WIND ADVISORY LEVELS. UPPER LOW BEGINS TO MOVE INTO EASTERN NEVADA AND CONTINUES TO LOWER HEIGHTS AND THICKNESS LEVELS FOR MONDAY. THERE WILL BE A CONTINUATION OF STRONG ONSHORE FLOW ACROSS THE AREA WITH TEMPS HAVING A TOUGH TIME MAKING OUT OF THE 60S IN MOST AREAS WITH A FEW LA/VTU COUNTY VALLEYS REACHING THE 70S. EXPECT MOSTLY CLOUDY SKIES WITH MARINE LAYER DEPTH REMAINING NEAR 4000 FT. SOUTHWEST TO WEST WINDS WILL REMAIN GUSTY ACROSS THE ANTELOPE VALLEY ON MONDAY...AND A WIND ADVISORY MIGHT BE NEEDED. THE TROF BEGINS TO CUT-OFF NEAR NV/CA BORDER EARLY TUESDAY MORNING WHICH SHOULD INCREASE NORTHERLY FLOW ACROSS THE MOUNTAINS INITIALLY TUESDAY MORNING...THEN WITH LOW CONTINUING TO PUSH SOUTHEAST OVER LOWER AZ...SOME DECENT OFFSHORE WINDS ARE POSSIBLE WITH SOME DECENT UPPER LEVEL SUPPORT. TEMPS WILL BEGIN TO WARM UP ON TUE AS RIDGE BEGINS TO BUILD IN FROM THE WEST. .LONG TERM (WEDNESDAY-SATURDAY)... ALTHOUGH THERE ARE SOME SLIGHT DISCREPANCIES...THE GFS AND ECMWF ARE IN GOOD AGREEMENT WED THROUGH FRI. BOTH MODELS SHOW THE RIDGE OFF THE CA COAST BUILDING THROUGH THU TO OVER 590 DM AND PERSISTING INTO FRI...ALL WHILE MOVING SLOWLY TO THE NORTHEAST WITH TIME. A MONSTER AND BROAD TROUGH COVERING THE ENTIRE CENTRAL US BARELY MOVES DURING THIS TIME...WHICH HELPS KEEP THE HIGH NEARBY BUT ALSO IMPEDES IT FROM BUILDING DIRECTLY OVER SOUTHERN CA. THE STRENGTH AND POSITION OF THIS BLOCKING TROUGH WILL GREATLY INFLUENCE THE POSITION OF THE RIDGE AFFECTING OUR AREA...AND THEREFORE WILL IMPACT JUST HOW WARM WE GET. NOT ONLY THAT...BUT THE RIDGE WILL NOT MOVE OUT OF THE AREA UNTIL THE TROUGH MOVES FARTHER EAST...SO WHEN WE COOL DOWN WILL ALSO MATTER GREATLY ON WHAT THIS TROUGH ENDS UP DOING. SINCE IT IS STILL A LITTLE WAYS AWAY...DID NOT GET TOO PRECISE WITH THE EXTENDED FORECAST. IT LOOKS SAFE TO SAY THAT IT WILL BE WARM AND WELL ABOVE NORMAL WED THROUGH SAT...BUT CONFIDENCE IN JUST HOW WARM WE GET AND FOR HOW LONG STILL LEAVES MUCH TO BE DESIRED. && .AVIATION...10/1800Z. A WEAK UPPER LEVEL TROUGH OF LOW PRESSURE CENTERED UPSTREAM ALONG 130W WILL BEGIN TO SHIFT EAST BY THE END OF THE PERIOD. LIGHT UPPER LEVEL SOUTHWEST WINDS WILL BECOME MODERATE LATE IN THE PERIOD. A WEAK PRESSURE GRADIENT WILL BECOME MODERATE AND ONSHORE WINDS WILL DEVELOP IN THE AFTERNOON. THE NEARSHORE EDDY WILL LIKELY REDEVELOP OVERNIGHT. THERE IS A CHANCE CIGS WILL DESCEND WHILE THE LOWER LEVELS WARM. KLAX...THERE IS A CHANCE CIGS WILL CONTINUE THROUGH THE EARLY PERIOD. IT IS LIKELY CIGS WILL RETURN DURING THE EVENING. THERE IS A CHANCE CIGS WILL DESCEND OVERNIGHT TO 010-015 IN THE LATER PERIOD. KBUR...THERE IS A CHANCE CIGS WILL CONTINUE THROUGH THE EARLY PERIOD. IT IS LIKELY CIGS WILL RETURN DURING THE EVENING. THERE IS A CHANCE CIGS WILL DESCEND OVERNIGHT TO 010-015 IN THE LATER PERIOD. VIRTUALLY CERTAIN - 95-100% VERY LIKELY - 80-95% LIKELY - 60-80% CHANCE - 30-60% NOT VERY LIKELY - 20% OR LESS && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...KAPLAN/KITTELL AVIATION..."30" WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT SAT MAY 10 2008 .SYNOPSIS...A NIGHT AND MORNING LOW CLOUDS AND FOG PATTERN WILL PREVAIL INTO SUNDAY...WITH A MOSTLY SUNNY AFTERNOON. AN INCREASING FLOW OF MARINE AIR OFF THE OCEAN WILL RESULT IN A MORE PERSISTENT CLOUD DECK ON MONDAY. AFTER ANOTHER DAY OF PERSISTENT LOW CLOUDS ON TUESDAY...A WARMING TREND WILL SET IN AS HIGH PRESSURE BUILDS DURING THE MID TO LATTER HALF OF THE WEEK...LEADING TO WELL ABOVE NORMAL TEMPERATURES BY THE WEEKEND. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH MONDAY)... MANY AREA AFTERNOON TEMPERATURES ARE UP 3 TO 5 DEGREES OR SO AS THE ONSHORE FLOW WEAKENS. THIS WARMING IS LIKELY TO BE SHORT LIVED AS AN UPPER LEVEL TROGH READIES ITSELF BEFORE DROPPING SOUTHEAST INTO THE PLATEAU. ALSO SUNDAY NIGHT THROUGH MONDAY THERE COULD BE A SWING BACK TO STRONGER ONSHORE FLOW...WITH A DEEPENING MARINE LAYER AND AN INCREASE IN THE DRIZZLE. COULD BE AN INCREASE IN THE WINDS IN THE MOUNTAINS AND DESERTS. AFTERNOON TEMPERATURES SUNDAY WILL BE LOWER THAN TODAY...AND ON MONDAY LOWER STILL. THERE IS AN INCREASE IN MOUNTAIN WINDS EXPECTED...BUT WINDS ARE EXPECTED TO BE BELOW ADVISORY CRITERIA. && .LONG TERM (TUESDAY THROUGH FRIDAY)... THERE IS A TRANSITION DAY ON TUESDAY AS HIGH PRESSURE PUSHES INTO THE PLATEAU. BY WEDNESDAY THROUGH FRIDAY THE RIDGE BUILDS EVEN STRONGER..AND COULD GET PRETTY WARM NEXT FRIDAY INTO THE WEEKEND. LATEST GUIDANCE HINTS AT 100 DEGREES CREEPING OUT OF THE DESERTS AND AT LEAST INTO THE INLAND VALLEYS NEXT WEEKEND. && .AVIATION... 101930Z...MDCRS SOUNDINGS INDICATE THE MARINE LAYER HAD LOWERED TO BETWEEN 2500 AND 3000 FEET FROM THIS MORNING. A LITTLE FURTHER LOWERING IS EXPECTED ON SUNDAY TO BETWEEN 2000 AND 2500 FEET BEFORE DEEPENING...AGAIN...SUNDAY NIGHT. STRATUS WITH BASES AROUND 2000 FEET SHOULD BEGIN TO PUSH BACK ONSHORE BY SUNSET AND INLAND DURING THE EVENING REACHING THE FAR INLAND VALLEY AREAS BEFORE MIDNIGHT. EXPECT THE STRATUS TO BREAK UP BETWEEN 16Z AND 18Z ON SUNDAY. VISIBILITIES IN THE MARINE LAYER SHOULD REMAIN GREATER THAN 6 MILES EXCEPT FOR AREAS OF 3 TO 5 MILES IN HAZE THROUGH SUNDAY. ABOVE THE MARINE LAYER...A MOSTLY CLEAR SKY WITH UNRESTRICTED VISIBILITIES WILL CONTINUE THROUGH SUNDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...SMALL AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 AM PDT SAT MAY 10 2008 .SYNOPSIS... DECREASING FLOW OF MARINE AIR OFF THE OCEAN WILL ALLOW SOME WARMING TO DEVELOP OVER THE REGION TODAY. NIGHT AND MORNING LOW CLOUDS WITH AFTERNOON SUNSHINE IS EXPECTED SUNDAY..BUT POSSIBLY MORE CLOUDS ON MONDAY. HIGH PRESSURE IS EXPECTED TO BUILD DURING THE MID TO LATTER HALF OF THE WEEK LEADING TO WELL ABOVE NORMAL TEMPERATURES BY THE WEEKEND. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH MONDAY)... THE STORM TRACK CONTINUES TO PUSH STORMS INTO THE PACIFIC NORTHWEST WITH PRESSURES PERIODICALLY RISING AND FALLING OVER THE PLATEAU. RISING PRESSURE TODAY HAS GENERATED A GOOD OFFSHORE TREND OVER OUR AREA... AND ALREADY THE SOUTH COAST HAS CLEARED. THIS SHOULD ALLOW A FEW DEGREES TO BE TACKED ON TODAY. TONIGHT AND SUNDAY MORNING THE LOW CLOUDS SHOULD RETURN...BUT WITH THE LOWERING TREND IN THE LOW CLOUDS THERE WILL BE A REDUCED POSSIBILITY OF DRIZZLE TONIGHT COMPARED TO THE WET STREETS WE WOKE UP TO IN SOME AREAS THIS MORNING. SUNDAY NIGHT THROUGH MONDAY THERE COULD BE A SWING BACK TO STRONGER ONSHORE FLOW...WITH A DEEPENING MARINE LAYER AND AN INCREASE IN THE DRIZZLE. COULD BE AN INCREASE IN THE WINDS IN THE MOUNTAINS AND DESERTS. && .LONG TERM (TUESDAY THROUGH FRIDAY)... THERE IS A TRANSITION DAY ON TUESDAY AS HIGH PRESSURE PUSHES INTO THE PLATEAU. BY WEDNESDAY THROUGH FRIDAY THE RIDGE BUILDS EVEN STRONGER..AND COULD GET PRETTY WARM NEXT FRIDAY INTO THE WEEKEND. WILL LOOK INTO THIS SOME MORE FOR THE AFTERNOON FORECAST PACKAGE. && .AVIATION... 101445Z...EARLY MORNING MDCRS SOUNDINGS AND THE 12Z NKX SOUNDING SHOW THE MARINE LAYER DEPTH BETWEEN 3500 AND 4000 FEET OVER THE AREA. THE MARINE LAYER IS EXPECTED TO LOWER TO BETWEEN 2500 AND 3000 FEET THIS AFTERNOON AND LOWER A LITTLE FURTHER ON SUNDAY BEFORE DEEPENING...AGAIN...SUNDAY NIGHT. STRATUS WITH BASES BETWEEN 2500 AND 3000 FEET MSL EXTENDS INLAND TO THE LOWER COASTAL SLOPES OF THE MOUNTAINS BUT WAS ALREADY BURNING OFF ALONG THE EASTERN EDGES OVER SOUTHERN SAN DIEGO COUNTY. EXPECT MOST INLAND AREAS TO SCATTER OUT BETWEEN 16Z AND 17Z AND COASTAL AREAS BETWEEN 17Z AND 19Z. STRATUS SHOULD BEGIN TO PUSH BACK ONSHORE BY SUNSET AND INLAND DURING THE EVENING REACHING THE FAR INLAND VALLEY AREAS BEFORE MIDNIGHT. ABOVE THE MARINE LAYER...A MOSTLY CLEAR SKY WITH UNRESTRICTED VISIBILITIES WILL CONTINUE THROUGH SUNDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...SMALL AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 PM PDT THU MAY 8 2008 .SYNOPSIS... ONSHORE FLOW WILL MAINTAIN A MODERATELY DEEP MARINE LAYER THROUGH EARLY NEXT WEEK WITH NIGHT AND MORNING COASTAL AND VALLEY LOW CLOUDS AND LOCAL FOG. ONLY MINOR CHANGES IN TEMPERATURE ARE EXPECTED UNTIL THE MIDDLE OF NEXT WEEK WHEN HIGH PRESSURE ALOFT WILL BRING WARMING AND FEWER LOW CLOUDS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... STRATUS WAS DEVELOPING RATHER SLOWLY TONIGHT...BUT A ROUGHLY 2000 FOOT MARINE LAYER SHOULD ALLOW MOST OF THE COASTAL AND VALLEY AREAS TO BECOME CLOUDY BY MORNING. SOME HIGH CLOUDS WILL DRIFT OVER TONIGHT AS WELL. WITH THE MARINE LAYER HAVING WEAKENED SOMEWHAT...DRIZZLE IS NOT EXPECTED TONIGHT OR FRI. WEAK HIGH PRESSURE ALOFT WILL CONTINUE AND BRING SEASONAL WEATHER TO THE MTNS/DESERTS WHILE THE MARINE LAYER WILL CONTINUE TO BRING SLIGHTLY BELOW AVERAGE TEMPS WEST OF THE MTNS. A TROUGH MOVING BY TO THE N/NE WILL DEEPEN THE MARINE LAYER EARLY NEXT WEEK AND BRING SLIGHT COOLING. HOWEVER...THERE IS A LOT OF VARIATION IN THE GFS ENSEMBLES WITH HOW DEEP THIS TROUGH WILL BE...SO THE AMOUNT OF COOLING/STRATUS INCREASES IS SOMEWHAT UNCERTAIN. MODELS ARE PRETTY CONSISTENT WITH HIGH PRESSURE ALOFT DEVELOPING OVER THE WESTERN US AROUND MIDWEEK...ESPECIALLY TO OUR NORTH WHICH WOULD PUT UNDER EAST FLOW ALOFT. THE UPPER LOW TO OUR SOUTH OR SOUTHWEST THAT THE MODELS HAVE HAD APPEARS TO BE FAIRLY WEAK AND THUS PROBABLY WOULD NOT BE ABLE TO ADVECT IN MOISTURE. REGARDLESS...A PRONOUNCED WARMING TREND SHOULD OCCUR AROUND THE WED/THU TIME FRAME. && .AVIATION... 090330Z...MARINE LAYER INVERSION BASED NEAR 2500 FT ON 00Z NKX WHILE SOME LOCAL AIRCRAFT SOUNDINGS ALSO SHOWED AN INVERSION NEAR 1600 FT. AFTER A BIG IMPROVEMENT IN CLEARING THIS AFTN...EXPECT STRATUS TO TAKE LONGER TO DEVELOP OVER THE COASTAL SECTIONS THIS EVE. STRATUS BASES APPROX 1500-2000 FT MSL SHOULD FORM NEAR KSAN/KCRQ/KSNA BY 06-07Z...AND GRADUALLY PUSH INTO THE INLAND VALLEYS LATE TONIGHT THRU 12Z FRI WITH AREAS OF TERRAIN OBSCURATION NEAR FOOTHILLS. EXPECT STRATUS TO BREAK UP AND RETREAT TO NEAR THE COASTLINE APPROX 18-20Z...HOWEVER AREAS OF LOW CLOUDS WILL LIKELY LINGER NEAR THE IMMEDIATE COAST AND BEACHES DURING FRI AFTN. MVFR VISIBILITY IN HAZE MAINLY INLAND ON FRI MORN WILL SLOWLY LIFT DURING THE DAY. THE STRATUS SHOULD BE QUICKER TO RETURN BY FRI EVE...MOVING BACK INTO COASTAL SECTIONS FROM 23-04Z. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...MAXWELL AVIATION...LAVIS
AREA FORECAST DISCUSSION
NWS UPTON NY
1221 PM EDT FRI MAY 9 2008 .SYNOPSIS... LOW PRESSURE SYSTEM PASSES JUST SOUTH OF THE REGION TODAY. HIGH PRESSURE THEN BUILDS IN FOR THE WEEKEND...WITH AN UPPER LEVEL DISTURBANCE MOVING THROUGH ON SATURDAY. ANOTHER LOW...WITH POTENTIALLY HEAVY RAINFALL...LIKELY AFFECTS THE REGION ON MONDAY...AND POTENTIALLY LINGERS INTO THE MIDWEEK PERIOD BEFORE WEAK HIGH PRESSURE BUILDS BACK IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BEST FGEN FORCING REMAINS 50-75 NM SOUTH OF LI...WITH MOD TO HEAVY RAINFALL REMAINING OFFSHORE. IT APPEARS THAT LATENT HEAT FLUX FROM EARLIER CONVECTION IS HELPING TO KEEP THE WARM...AND HENCE THE STORM TRACK FURTHER OFFSHORE THAN PREVIOUSLY FORECAST. THE RESULT IS A MORE SOUTHERN PRECIP DISTRIBUTION. THE FLOOD WATCH WAS CANCELLED JUST A BIT AGO. ALTHOUGH SOME AREA WILL SEE PERIODS OF BRIEF HEAVY RAIN...URBAN AND SMALL STREAM FLOODING SHOULD BE THE EXTENT OF THE PROBLEMS. NYC AND THE MORE FLOOD PRONE NORTHERN NJ RIVERS WILL RECEIVE THE LEAST AMOUNT OF PRECIP THIS AFTERNOON. RECENT DATA INDICATED A DEVELOPING NELY LL JET OF 50KT ACROSS EXTREME EASTERN LI AND THE MASS ISLANDS. GIVEN CURRENT BUOY WIND DATA AND BUFKIT FORECASTS...ISSUED A WIND ADVISORY FOR EASTERN LI FOR THIS AFTERNOON AND EVENING. THE NORTH SHORE OF LI MAY SEE A FEW GUSTS CLOSE TO ADVISORY LEVELS...BUT THE EXPOSED FORKS ARE A MORE LIKELY TARGET. 12Z NAM INITIALIZATION WAS VERY GOOD IN TERMS OF PRESSURE AND MOVEMENT OF THE SYSTEM OVER SOUTHERN NJ. PRECIP DISTRIBUTION WAS ALSO GOOD...BUT MAY HAVE BEEN A BIT OVER DONE WITH WHAT PRECIP REMAINS OVER MAINLAND NJ BASED ON SURFACE REPORTS. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... BEST FORCING CONTINUES TO REMAIN OFFSHORE...BUT LOCALLY MODERATE RAIN WILL BE WIND DRIVEN...MAKING FOR A PRETTY MISERABLE EVENING FOR EASTERN LI. ELSEWHERE RAIN BECOMES MORE SPORADIC. A LARGE SWATH OF WRAP AROUND PRECIP WILL KEEP POPS IN THE FORECAST THROUGH AT LEAST SAT AFTERNOON. GUSTY NORTHERLY WINDS SHOULD REMAIN BELOW ADVISORY CRITERIA...EXCEPT FOR EASTERLY LI TONIGHT THROUGH EARLY SATURDAY. SHORT WAVE PASSES JUST OFF TO THE SOUTH SATURDAY EVENING...THEN HIGH PRESSURE BUILDS INTO REGION WITH CLEARING SKIES. SUNDAY WILL FEATURE SUNSHINE FILTERED BY CIRRUS...BUT MORE NOTICEABLE DURING THE AFTERNOON. A FINE DAY NEVERTHELESS...WITH HIGHS WELL INTO THE 60S TO AROUND 70. CLOUDS LOWER AND THICKEN SUNDAY NIGHT OUT AHEAD OF THE NEXT SYSTEM. SCALED BACK ON POPS...AND LOWERED THEM TO CHC FOR THE OVERNIGHT HOURS. EAST WINDS PICK UP AS THE NIGHT PROGRESSES. && .LONG TERM /MONDAY THROUGH THURSDAY/... CHANCES FOR RAIN WILL INCREASE ON MONDAY...AND COULD BE HEAVY AT TIMES AS THIS NEXT STORM PASSES TO THE SOUTH OF LONG ISLAND...WITH STRONG FRONTOGENETIC FORCING AND UPPER DIVERGENCE OVER THE AREA. POTENTIAL FOR A 1 TO 2 INCH RAINFALL EVENT. WINDS WILL SHIFT TO THE NORTHEAST MONDAY EVENING...THEN NORTH LATE AS THE LOW MOVES TO OUR SOUTH AND EAST. WITH THE UPPER LOW BEING SLOW TO DEPART (ECMWF SLOWER THAN THE GFS)...HAVE KEPT HIGH CHC POPS IN MON NIGHT AND GRADUALLY TAPERED THEM DOWN ON TUE. WEAK HIGH PRESSURE RETURNS FOR WEDNESDAY...BUT THE PARADE OF STORMS CONTINUES ON THU AS THE NEXT FRONTAL SYSTEM APPROACHES. POTENTIAL FOR ANOTHER PROLONGED PERIOD OF RAIN EXISTS. SFC FEATURES LOOK VERY SIMILAR TO THE MON STORM...AND THE GFS AND EC AGREE TO AN EXTENT...BUT THIS IS DAY 8 AND THINGS MAY CHANGE BETWEEN NOW AND THEN. FLOODING PROBLEMS WILL BE A CONCERN FOR BOTH THE SUN NIGHT/MON STORM AND THE THU STORM. HAVE HIGHER CONFIDENCE WITH THE MON STORM AS MODELS HAVE BEEN VERY CONSISTENT OVER THE LAST 24 HOURS...SO WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... OVERNIGHT CONVECTION DID NOT HOLD TOGETHER AS ORIGINALLY EXPECTED... SO VFR CONDITIONS IN LIGHT RAIN PREVAIL ATTM. HEAVIER RAIN OVER SOUTHERN NJ BACK TOWARD WASHINGTON DC WILL EVENTUALLY MAKE IT INTO THE AREA...WITH NYC AREA TERMINALS LOWERING TO IFR BY LATE MORNING...AND TERMINALS NORTH/EAST FOLLOWING SUIT BY MIDDAY OR EARLY AFTERNOON. WILL CONTINUE TO EXCLUDE THUNDER...AS ANY ELEVATED INSTABILITY SHOWN BY UPSTREAM ACARS SOUNDINGS REMAINS RELATIVELY SHALLOW AND MORE CONDUCIVE TO MODERATE/HEAVY RAIN. E-NW WINDS WILL ALSO CONTINUE TO INCREASE TODAY AS INTENSIFYING LOW PRESSURE OVER VIRGINIA MOVES E-NE AND PASSES SOUTH OF LONG ISLAND EARLY THIS EVENING. A LOW LEVEL EASTERLY JET INCREASING TO 45-50 KT SHOULD LEAD TO HEAVY RAIN AND LLWS THIS AFTERNOON AND OUT EAST AT KGON LATER TODAY INTO THIS EVENING. AS THE LOW PASSES BY...FLOW BECOMES NORTHERLY TONIGHT...AND IMPROVEMENT TO MVFR LOOKS POSSIBLE THIS EVENING AT NYC AREA TERMINALS...BUT IFR SHOULD HOLD ON FARTHER EAST AT KBDR/KGON/KISP...IMPROVING TO MVFR LATE. OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... SUB-VFR CONDITIONS WILL SLOWLY IMPROVE TO VFR DURING SAT MORNING... WITH GUSTY NORTHERLY FLOW CONTINUING THROUGH THE AFTERNOON AS WELL. SUB-VFR CONDITIONS WITH GUSTY NE WINDS EXPECTED ONCE AGAIN SUN NIGHT THROUGH MON AS ANOTHER STORM SYSTEM PASSES OVER THE REGION. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY TUE. && .MARINE... E-NE WINDS COMING UP QUICKLY...BUT REMAINING IN SCA TERRITORY. GALES GO INTO EFFECT THIS EVENING...AND THE CURRENT DATA SUPPORTS IT...SO NO CHANGES PLANNED TO THE HEADLINES. LLJ OF 50KT ACROSS EASTERN WATERS MAY RESULT IN A FEW NEAR-STORM FORCE GUSTS TONIGHT. WINDS AND SEAS START TO DIMINISH EARLY SAT. SCA CONDITIONS COULD LAST ON THE EASTERN SOUND/BAY WATERS THROUGH THE DAY ON SAT...AND INTO EARLY SAT EVENING ON THE OCEAN. THEN QUIET FOR SUNDAY AND SUNDAY EVENING BEFORE NEXT LOW PRESSURE SYSTEM ARRIVES. GALES ARE ONCE AGAIN POSSIBLE ON THE OCEAN ON MON...WITH SCA ELSEWHERE. SCA SEAS COULD LINGER ON THE EASTERN OCEAN ZONES INTO TUE NIGHT BEFORE SUBSIDING. && .HYDROLOGY... FLOOD WATCH CANCELLED. THE BULK OF HEAVIEST PRECIP REMAINING OFFSHORE. LOCALIZED HEAVIER RAIN IS STILL POSSIBLE ACROSS THE TRI STATE AREA THIS EVENING...BUT IT SHOULD BE SHORT LIVED AND NOT PRODUCE MORE THAN URBAN AND SMALL STREAM/EXCESS RUNOFF PROBLEMS. WITH THE SECOND STORM SYSTEM SUN NIGHT-MON THERE IS THE POTENTIAL FOR 1-2 INCHES OF ADDITIONAL RAINFALL. HOWEVER THERE IS SOME UNCERTAINTY ON THE TRACK OF THE NEXT SYSTEM. && .TIDES/COASTAL FLOODING... HIGH TIDE OF CONCERN IS TONIGHT. AT THIS TIME...IT APPEARS THAT MAX DEPARTURES WILL BE ON THE 1 TO 2 FOOT RANGE...WITH THE WESTERN GREAT SOUTH BAY AND WESTERN SOUND THE MOST SUSCEPTIBLE. FORTUNATELY...THE GREATEST DEPARTURES SHOULD OCCUR MOSTLY BETWEEN HIGH TIDES...AND IT APPEARS THAT WINDS WILL BACK TO A MORE NORTHERLY DIRECTION THIS EVENING...SO THE THINKING IS THAT MINOR COASTAL FLOODING IS POSSIBLE BUT NOT DEFINITE FOR THE LOCATIONS MENTIONED ABOVE. WILL HOLD OFF ON ISSUING ADVISORY ATTM. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 8 AM EDT SATURDAY FOR NYZ079-081. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ338. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR ANZ330- 340-350-353-355. GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT SATURDAY FOR ANZ330-340-350-353-355. SMALL CRAFT ADVISORY UNTIL 12 PM EDT SATURDAY FOR ANZ335-345. && $$ SYNOPSIS...BS NEAR TERM...BS SHORT TERM...BS LONG TERM...JC/AL AVIATION...BG MARINE...BS HYDROLOGY...BS TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS UPTON NY
744 AM EDT FRI MAY 9 2008 .SYNOPSIS... LOW PRESSURE SYSTEM PASSES JUST SOUTH OF THE REGION TODAY WITH HEAVY RAIN. HIGH PRESSURE THEN BUILDS IN FOR THE WEEKEND...WITH AN UPPER LEVEL DISTURBANCE MOVING THROUGH ON SATURDAY. ANOTHER LOW...WITH POTENTIALLY HEAVY RAINFALL...LIKELY AFFECTS THE REGION ON MONDAY...AND POTENTIALLY LINGERS INTO THE MIDWEEK PERIOD BEFORE WEAK HIGH PRESSURE BUILDS BACK IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RAIN IN ASSOCIATION WITH LOW PRESSURE TO THE SOUTHWEST HAS SPREAD INTO THE WESTERN HALF OF THE CWA...AND WILL CONTINUE TO OVERSPREAD THE REST OF THE CWA THIS MORNING. ISENTROPIC LIFT OUT AHEAD OF THE LOW IS FORECAST TO BE AT ITS STRONGEST OVER THE TRI STATE REGION LATE THIS MORNING INTO THE AFTERNOON. AT THE SAME TIME MODELS SHOWING MID LEVEL FRONTOGENETIC FORCING AND GOOD OMEGA...ALONG WITH AND 850 THETA-E RIDGE OVER THE AREA. ADDITIONALLY...PWATS IN THE RANGE OF 1.25 TO 1.5 INCHES. HEAVIEST RAINFALL EXPECTED TO REACH SW PORTION OF CWA LATE IN THE MORNING/NOONTIME...THEN SPREAD NORTH AND EAST THROUGH THE REST OF THE AFTERNOON...ALTHOUGH RAIN SHOULD BE AT LEAST MODERATE DURING THE MORNING COMMUTE FOR MANY SPOTS...AND POSSIBLY HEAVY AT TIMES. MID LEVEL LAPSE RATES ABOVE THE INVERSION WHICH WILL BE IN PLACE DO NOT LOOK STEEP ENOUGH TO MENTION THUNDER...ALTHOUGH PLENTY OF LIGHTNING STRIKES NOTED EARLIER THIS MORNING OVER MARYLAND AND DELAWARE...EVEN A FEW AS FAR NORTH AS CENTRAL NJ. NAM IS SLIGHTLY SLOWER AND STRONGER WITH THE LOW THAN ITS PAST COUPLE OF RUNS...BUT CONTINUES TO BOTH MOVE THE LOW OFF THE SOUTH JERSEY SHORE DURING THE AFTERNOON...AND HAVE THE AXIS OF HEAVIEST QPF MOVING THROUGH THE CWA. QPF IS ALSO LOWER THAN PREVIOUS RUNS...BUT STILL SHOWING GENERALLY 2 TO 2.5 INCHES FOR THE ENTIRE EVENT. GFS SHOWING ABOUT THE SAME QPF AMOUNTS ACROSS THE CWA...WHICH IS A GENERAL INCREASE FROM ITS PREVIOUS COUPLE OF RUNS...SO THE TWO MODELS ARE CONVERGING IN THIS REGARD. GFS IS JUST A LITTLE FASTER WITH HEAVIER PRECIP. EXPECTING A FAIRLY UNIFORM RAINFALL ACROSS THE CWA...WITH BEST CHANCE FOR HIGHEST AMOUNTS GENERALLY FARTHER SOUTH AND EAST WHERE THE HIGHEST PWATS...THETA-E RIDGE AND ISENTROPIC LIFT WILL APPEAR TO BE. FLOOD WATCHES WILL REMAIN UNCHANGED...AS ACCUMULATIONS AND DISTRIBUTION ARE SIMILAR TO PREVIOUS THINKING. MAINLY URBANIZED FLOODING EXPECTED AND SMALL STREAM FLOODING. MORE DETAILS IN THE HYDROLOGY SECTION BELOW. HIGH TEMPERATURES FOR THE DAY HAVE ALREADY OCCURRED FOR MOST SPOTS AS RAIN-COOLED AIR WILL PRODUCE TEMPERATURES FALLING THROUGH THE 50S DURING THE DAY...AND INTO THE UPPER 40S FOR SOME LOCALES. WINDS FROM THE NORTHEAST WILL INCREASE...AND IT WILL BECOME QUITE BREEZY AS WELL...BUT IT LOOKS LIKE WE WILL FALL SHORT OF WIND ADVISORY CRITERIA. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... THE LOW WILL MOVE TO A POSITION APPROX 50-75 MILES NE OF 40/70 BENCHMARK BY 12Z SATURDAY. POPS DIMINISH TO CHANCE FOR WESTERN HALF OF CWA...WHILE REMAINING LIKELY TO CATEGORICAL EAST. RAIN STILL MAY FALL HEAVILY DURING THE EVENING HOURS ACROSS EASTERN LONG ISLAND AND SOUTHEAST CT...WITH DECENT FORCING STILL PRESENT. STILL BREEZY...BUT AGAIN SHORT OF ANY ADVISORY CRITERIA. CHANCE OF A LINGERING SHOWER FOR THE EASTERN THIRD OF CWA SATURDAY MORNING...THEN PARTIAL SUNSHINE EVERYWHERE DURING THE AFTERNOON. A SHORT WAVE WILL APPROACH FROM THE WEST...BUT IT APPEARS TO ARRIVE TO LATE TO TAP INTO DAYTIME INSTABILITY AND MOISTURE...SO WENT WITH A DRY AFTERNOON AND EVENING. MAV/FWC BLEND FOR TEMPS LOOKED GOOD...WITH SATURDAY`S HIGHS MOSTLY 60-65. SHORT WAVE PASSES JUST OFF TO THE SOUTH SATURDAY EVENING...THEN HIGH PRESSURE BUILDS INTO REGION WITH CLEARING SKIES. SUNDAY WILL FEATURE SUNSHINE FILTERED BY CIRRUS...BUT MORE NOTICEABLE DURING THE AFTERNOON. A FINE DAY NEVERTHELESS...WITH HIGHS WELL INTO THE 60S TO AROUND 70. CLOUDS LOWER AND THICKEN SUNDAY NIGHT OUT AHEAD OF THE NEXT SYSTEM. SCALED BACK ON POPS...AND LOWERED THEM TO CHC FOR THE OVERNIGHT HOURS. EAST WINDS PICK UP AS THE NIGHT PROGRESSES. && .LONG TERM /MONDAY THROUGH THURSDAY/... CHANCES FOR RAIN WILL INCREASE ON MONDAY...AND COULD BE HEAVY AT TIMES AS THIS NEXT STORM PASSES TO THE SOUTH OF LONG ISLAND...WITH STRONG FRONTOGENETIC FORCING AND UPPER DIVERGENCE OVER THE AREA. POTENTIAL FOR A 1 TO 2 INCH RAINFALL EVENT. WINDS WILL SHIFT TO THE NORTHEAST MONDAY EVENING...THEN NORTH LATE AS THE LOW MOVES TO OUR SOUTH AND EAST. WITH THE UPPER LOW BEING SLOW TO DEPART (ECMWF SLOWER THAN THE GFS)...HAVE KEPT HIGH CHC POPS IN MON NIGHT AND GRADUALLY TAPERED THEM DOWN ON TUE. WEAK HIGH PRESSURE RETURNS FOR WEDNESDAY...BUT THE PARADE OF STORMS CONTINUES ON THU AS THE NEXT FRONTAL SYSTEM APPROACHES. POTENTIAL FOR ANOTHER PROLONGED PERIOD OF RAIN EXISTS. SFC FEATURES LOOK VERY SIMILAR TO THE MON STORM...AND THE GFS AND EC AGREE TO AN EXTENT...BUT THIS IS DAY 8 AND THINGS MAY CHANGE BETWEEN NOW AND THEN. FLOODING PROBLEMS WILL BE A CONCERN FOR BOTH THE SUN NIGHT/MON STORM AND THE THU STORM. HAVE HIGHER CONFIDENCE WITH THE MON STORM AS MODELS HAVE BEEN VERY CONSISTENT OVER THE LAST 24 HOURS...SO WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... OVERNIGHT CONVECTION DID NOT HOLD TOGETHER AS ORIGINALLY EXPECTED... SO VFR CONDITIONS IN LIGHT RAIN PREVAIL ATTM. HEAVIER RAIN OVER SOUTHERN NJ BACK TOWARD WASHINGTON DC WILL EVENTUALLY MAKE IT INTO THE AREA...WITH NYC AREA TERMINALS LOWERING TO IFR BY LATE MORNING...AND TERMINALS NORTH/EAST FOLLOWING SUIT BY MIDDAY OR EARLY AFTERNOON. WILL CONTINUE TO EXCLUDE THUNDER...AS ANY ELEVATED INSTABILITY SHOWN BY UPSTREAM ACARS SOUNDINGS REMAINS RELATIVELY SHALLOW AND MORE CONDUCIVE TO MODERATE/HEAVY RAIN. E-NW WINDS WILL ALSO CONTINUE TO INCREASE TODAY AS INTENSIFYING LOW PRESSURE OVER VIRGINIA MOVES E-NE AND PASSES SOUTH OF LONG ISLAND EARLY THIS EVENING. A LOW LEVEL EASTERLY JET INCREASING TO 45-50 KT SHOULD LEAD TO HEAVY RAIN AND LLWS THIS AFTERNOON AND OUT EAST AT KGON LATER TODAY INTO THIS EVENING. AS THE LOW PASSES BY...FLOW BECOMES NORTHERLY TONIGHT...AND IMPROVEMENT TO MVFR LOOKS POSSIBLE THIS EVENING AT NYC AREA TERMINALS...BUT IFR SHOULD HOLD ON FARTHER EAST AT KBDR/KGON/KISP...IMPROVING TO MVFR LATE. OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... SUB-VFR CONDITIONS WILL SLOWLY IMPROVE TO VFR DURING SAT MORNING... WITH GUSTY NORTHERLY FLOW CONTINUING THROUGH THE AFTERNOON AS WELL. SUB-VFR CONDITIONS WITH GUSTY NE WINDS EXPECTED ONCE AGAIN SUN NIGHT THROUGH MON AS ANOTHER STORM SYSTEM PASSES OVER THE REGION. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY TUE. && .MARINE... E-NE WINDS COME UP QUICKLY TODAY...AND A BRIEF WINDOW OF OCCASIONAL 35 KT GUSTS IS POSSIBLE ON THE OCEAN WATERS AND EASTERN LONG ISLAND SOUND THIS AFTERNOON AS EASTERLY LOW LEVEL JET PASSES OVERHEAD. ALL MODEL GUIDANCE INDICATES A BRIEF LULL IN THE WINDS AS THIS FIRST LLJ PASSES BEFORE RAMPING UP AGAIN THIS EVENING...WITH SOLID GALES THEREAFTER FOR TONIGHT ON THE OCEAN AND EASTERN SOUND/BAY WATERS...SO HAVE DECIDED TO LIMIT GALE WARNING TO TONIGHT. WINDS AND SEAS START TO DIMINISH LATE TONIGHT. SCA CONDITIONS COULD LAST ON THE EASTERN SOUND/BAY WATERS THROUGH THE DAY ON SAT...AND INTO EARLY SAT EVENING ON THE OCEAN. THEN QUIET FOR SUNDAY AND SUNDAY EVENING BEFORE NEXT LOW PRESSURE SYSTEM ARRIVES. GALES ARE ONCE AGAIN POSSIBLE ON THE OCEAN ON MON...WITH SCA ELSEWHERE. SCA SEAS COULD LINGER ON THE EASTERN OCEAN ZONES INTO TUE NIGHT BEFORE SUBSIDING. && .HYDROLOGY... FLOOD WATCH - NYC METRO URBAN AREAS - FOR TODAY INTO EARLY THIS EVENING. EXPECTING A 2 TO 2.5 INCH RAINFALL WITH LOCALLY UP TO AROUND 3 INCHES. TIMING OF HEAVIEST PRECIP MOST LIKELY LATE MORNING INTO THE FIRST HALF OF THE AFTERNOON WHERE THE WATCH IS POSTED. MAX HOURLY RAINFALL TOTAL RATES OF 0.50 TO 0.75 INCHES ARE EXPECTED...BUT THESE FALL SHORT OF FLASH FLOOD GUIDANCE. THINKING IS THAT 3-6 HOUR FFG AMOUNTS OF 2 INCHES IN 3 HOURS AND 2.5 INCHES IN 6 HOURS ARE STILL POSSIBLE IF BANDING SETS UP ACROSS THE REGION DURING THE MID DAY PERIOD. THUS, NOT EXPECTING WATER RESCUES...BUT MORE WIDESPREAD URBAN AND SMALL STREAM FLOODING...THAT COULD APPROACH WARNING CRITERIA DUE TO ROAD CLOSURES...FLOODED BASEMENTS...ETC. WITH THE SECOND STORM SYSTEM SUN NIGHT-MON THERE IS THE POTENTIAL FOR 1-2 INCHES OF ADDITIONAL RAINFALL. HOWEVER THERE IS SOME UNCERTAINTY ON THE TRACK OF THE NEXT SYSTEM. WILL MENTION FLOOD POTENTIAL SCENARIO IN HWO. && .TIDES/COASTAL FLOODING... HIGH TIDE OF CONCERN IS TONIGHT. AT THIS TIME...IT APPEARS THAT MAX DEPARTURES WILL BE ON THE 1 TO 2 FOOT RANGE...WITH THE WESTERN GREAT SOUTH BAY AND WESTERN SOUND THE MOST SUSCEPTIBLE. FORTUNATELY...THE GREATEST DEPARTURES SHOULD OCCUR MOSTLY BETWEEN HIGH TIDES...AND IT APPEARS THAT WINDS WILL BACK TO A MORE NORTHERLY DIRECTION THIS EVENING...SO THE THINKING IS THAT MINOR COASTAL FLOODING IS POSSIBLE BUT NOT DEFINITE FOR THE LOCATIONS MENTIONED ABOVE. WILL HOLD OFF ON ISSUING ADVISORY ATTM. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM 8 AM EDT THIS MORNING THROUGH THIS EVENING FOR CTZ009. NY...FLOOD WATCH FROM 8 AM EDT THIS MORNING THROUGH THIS EVENING FOR NYZ071>081. NJ...FLOOD WATCH FROM 8 AM EDT THIS MORNING THROUGH THIS EVENING FOR NJZ003>006-011. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 12 PM EDT SATURDAY FOR ANZ335-345. SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS AFTERNOON FOR ANZ330-340. GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT SATURDAY FOR ANZ330-340-350-353-355. SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EDT SATURDAY FOR ANZ338. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR ANZ350- 353-355. && $$ SYNOPSIS...JC NEAR TERM...JC SHORT TERM...JC LONG TERM...JC/AL AVIATION...BG MARINE...BG HYDROLOGY...JC TIDES/COASTAL FLOODING...BG
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
331 PM EDT SAT MAY 10 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE MID-ATLANTIC TONIGHT. THIS HIGH WILL MOVE OFF THE COAST SUNDAY AND THE NEXT STORM SYSTEM WILL APPROACH FROM THE WEST. THIS STORM WILL SLOWLY PASS BY TO OUR SOUTH SUNDAY NIGHT AND MONDAY BRINGING A GOOD CHANCE FOR SIGNIFICANT RAIN. HIGH PRESSURE WILL RETURN FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... WATER VAPOR LOOP SHOWS A SHORT WAVE OVER SOUTHERN PENNSYLVANIA LIFTING NORTHEAST...WITH RIDGING OCCURRING ACROSS THE CENTRAL CONUS AHEAD OF THE DEVELOPING SYSTEM OVER THE ROCKIES. ACARS 400-250MB WIND OBSERVATIONS SHOW A 100-140KT ANTICYCLONICALLY CURVED JET FROM THE FOUR CORNERS REGION INTO THE CAROLINAS. 11Z SURFACE ANALYSIS PLACED A 1005MB OCCLUDED CYCLONE NEAR CHARLOTTESVILLE...WITH OCCLUSION FRONT SOUTH TO NEAR ATLANTA. THE BAROCLINIC ZONE RUNS EAST ACROSS THE GULF STATES AND SOUTH CAROLINA. A 1015MB ANTICYCLONE DOMINATES THE GREAT LAKES REGION. CLOUDS DISSIPATING GRADUALLY AS THE SHORT WAVE PROGRESSES TO THE NORTHEAST. FLOW HAS BECOME NORTHERLY AS HIGH PRESSURE BUILDS IN BEHIND THE OCCLUDED FRONT. THERE COULD BE SOME POCKETS OF FOG...ESPECIALLY ALONG RIVER VALLEYS AS THE SKIES CLEAR OVERNIGHT. UPPER LEVEL CLOUDS ARRIVE LATE DURING THE NIGHT AS THE NEXT SYSTEM APPROACHES. FOR LOW TEMPERATURES...WENT WITH THE COOLER FWC GUIDANCE AS DEW POINTS DROP THIS EVENING...HOWEVER FORECAST READINGS ARE TOO WARM TO SUPPORT ANY MENTION OF FROST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... WARM SECTOR REMAINS ACROSS THE CAROLINAS TOMORROW AS THE NEXT SYSTEM APPROACHES FROM THE WEST. DEEP HEIGHT FALLS ALOFT SHOULD SUPPORT STRENGTHENING ISENTROPIC LIFT FROM THE SOUTH DURING THE AFTERNOON. WITH RECENT FLOODING...THERE IS ENOUGH CONFIDENCE TO RAISE A FLOOD WATCH. HOWEVER...THIS TIME THERE WONT BE CONVECTIVE ENHANCEMENT ACROSS THE REGION...WHICH WOULD CUT DOWN ON QPF. ADDITIONALLY...FORECAST CONVECTION ACROSS THE CAROLINAS COULD ALTER THE MOISTURE FEED INTO THE REGION...SLOWING THE ARRIVAL OF PRECIPITATION ALONG THE OCCLUDED BOUNDARY FROM THE SOUTHWEST. TIGHTENING PRESSURE GRADIENT SHOULD SUPPORT 30 MPH WIND GUSTS FROM THE SOUTHEAST TOMORROW AFTERNOON. TEMPERATURE FORECAST MAY NEED TO BE ADJUSTED SHOULD TIME OF PRECIPITATION ARRIVAL SHIFT SEVERAL HOURS. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... BY 00Z MON...CYCLONE WL BE IN OHVLY...W/ TRIPLE PT LOW OFF CAROLINA COAST. H5 S/WV ENERGY UNDERCUTS LOW...DEEPENING SFC SYSTM...AND RESULTING IN A NEGATIVELY TILTED UPR TROF AXIS. PLENTY OF ATLC INFLOW. DEPENDING UPON INTERACTIONS...AND EVOLUTION OF CNVCTN S OF CWFA...GLFMEX MAY OR MAY NOT BE AVBL TOO. CERTAINLY...CWFA WL BE FAR ENUF N SO THAT STRONG TSRA NOT A CONCERN. /TRACK OF LOW ATTM NRN NC-SRN VA/. GDNC RIGHT NOW SUGGESTING THAT GLFMEX MSTR WL STREAM NWD TOO. THAT REMAINS TO BE SEEN. BUT... PWAT NEAR AN INCH OVR WET SOIL /HV NOT HAD MUCH OPPORTUNITY FOR DRYING RECENTLY/...FFG VALUES GREATLY REDUCED. IF IT WERENT FOR THU-FRI RAINS /2-4+ INCHES CNTRL-ERN CWFA/...SUN NGT WUDNT BE AN ISSUE. HWVR...RELATIVELY STRONG CONFIDENCE THAT 2 INCHES PSBL IN 12-24 HRS CENTERED ON SUN NGT-MON MRNG...AND THATS A PROBLEM. A FEW DETAILS NEED TO BE WORKED OUT-- SUCH AS MAX QPF...ITS TIMING... AND PLACEMENT-- BUT ATTM THE PRO/S OUTWEIGH THE CON/S. WL BE GOING W/ A FLOOD WATCH ENTIRE AREA THRU MON MRNG...AND INTO ELY AFTN BALT-WASH METRO. CYCLONE WL WOBBLE OFF CST MON NGT...FOR A RDG OF HIPRES WHICH WL LAST THRU WED. NEXT STORM STILL PROGGED FOR END OF WK. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... SKIES CLEAR THIS EVENING AND WINDS LIGHTEN IN SURFACE RIDGE. PATCHY FOG MAY DEVELOP ESPECIALLY NEAR RIVER VALLEYS OVERNIGHT. SOUTHEASTERLY FLOW DEVELOPS DURING THE MORNING AS MID CLOUDS MOVE IN AHEAD OF THE NEXT STORM SYSTEM. MVFR-IFR EXPECTED BY EVENING IN APPROACHING RAIN. MVFR-IFR XPCTD MUCH OF SUN NGT IN RA. IN ADDITION...XPCTG STRONG WNDS BACKING FM SE TO N. CONDS WL IMPV MON...AND WL BE VFR THRU WED. && .MARINE... STRONG SMALL CRAFT CONDITIONS DEVELOP TOMORROW AFTERNOON AS SOUTHEASTERLY FLOW BECOMES GUSTY AHEAD OF THE NEXT STORM SYSTEM. STRONG LOPRES JUST S OF WATERS WL LEAD TO A TIGHT P-GRAD SUN NGT. MOMENTUM TRANSFER SUGGEST 35-40KT W/IN REACH. WL PLAY IT CONSERVATIVE...AND WL RAISE GLW FOR LWR PTMC AND MD BAY FOR 35 KT. THAT MAY NEED TO BE EXPANDED AND MAX GUST RAISED...BUT ITS A START. WNDS BACK N/NW MON. WNDS WL DROP BACK INTO SCA RANGE...BUT CUD RISE BACK INTO GLW COINCIDENT W/ MIXING MON. ATTM...WONT CARRY ANY HEADLINES BYD 12Z MON...BUT LATER SHIFTS WL NEED TO. GUSTY WNDS WL CONT THRU TUE /SCA LIKELY/...THEN SUBSIDE AS HIPRES RTNS. && .HYDROLOGY... ONE AND A HALF TO THREE INCHES OF RAIN LIKELY SUN NGT-MON MRNG. 12 HR FFG GNLY BTWN 1-2 INCHES. THAT MEANS A SMALL STREAM/CREEK FLOOD THREAT EXISTS. THAT WATER WL FLOW INTO GAGED WATERWAYS MON...LEADING TO RAPID W/IN BANK RISES. SOME OF THE MORE FLOOD PRONE WATERWAYS MAY REACH/EXCEED FLOOD STAGE. AS DISCUSSED ABV...FLOOD WATCH WL BE RAISED. ALSO NEED TO MONITOR RIVER FCSTS FOR PSBL RIVER FLOOD WRNGS BY MON. && .TIDES/COASTAL FLOODING... THE LUNAR PHASE IS CURRENTLY 35 PERCENT FULL...AND IS WAXING TOWARD A QUARTER MOON. TIDES ARE CURRENTLY RUNNING AT OR SLIGHTLY BELOW ASTRONOMICAL PREDICTIONS. AS SOUTHEASTERLY WINDS INCREASE SUNDAY...POSITIVE WATER LEVEL DEPARTURES ARE EXPECTED TO DEVELOP. GIVEN THE CURRENT STORM TRACK...WINDS STRENGTHEN AND REMAIN AT A FAVORABLE DIRECTION FOR BUILDING DEPARTURES INTO MONDAY MORNING. BLOWOUT CONDITIONS EXPECTED BEHIND THE STORM SYSTEM LATE MONDAY. WILL HAVE TO MONITOR WATER LEVELS EARLY NEXT WEEK...BUT WITH ASTRONOMICAL TIDES NEAR A MINIMUM FOR THE MONTH...WILL HAVE TO HAVE 1-2 FOOT DEPARTURES TO ACHIEVE MINOR COASTAL FLOOD PROBLEMS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...FLOOD WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR DCZ001. MD...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR MDZ003-501-502. FLOOD WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR MDZ004>007-009>011-013-014-016>018. VA...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR VAZ021-025>031-036>040-050-051-056. FLOOD WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR VAZ041-042-052>055-057. WV...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING FOR WVZ050>055-501>504. MARINE...SMALL CRAFT ADVISORY FROM 12 PM TO 6 PM EDT SUNDAY FOR ANZ530>534-537. GALE WARNING FROM 6 PM SUNDAY TO 9 AM EDT MONDAY FOR ANZ530>534-537. SMALL CRAFT ADVISORY FROM 12 PM SUNDAY TO 9 AM EDT MONDAY FOR ANZ535-536. && $$ SYNOPSIS...HTS NEAR TERM...ROGOWSKI SHORT TERM...ROGOWSKI LONG TERM...HTS AVIATION...ROGOWSKI/HTS MARINE...ROGOWSKI/HTS HYDROLOGY...HTS TIDES/COASTAL FLOODING...ROGOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
1253 PM EDT SAT MAY 10 2008 .SYNOPSIS... A WEAK AREA OF LOW PRESSURE WILL PASS BY TO OUR SOUTH EARLY THIS AFTERNOON. HIGH PRESSURE WILL BUILD OVER THE MID-ATLANTIC TONIGHT. THIS HIGH WILL MOVE OFF THE COAST SUNDAY AND THE NEXT STORM SYSTEM WILL APPROACH FROM THE WEST. THIS STORM WILL SLOWLY PASS BY TO OUR SOUTH SUNDAY NIGHT AND MONDAY BRINGING A GOOD CHANCE FOR SIGNIFICANT RAIN. HIGH PRESSURE WILL RETURN FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO REMOVE POPS AS MOISTURE PULLS NORTHEAST OF THE REGION. WATER VAPOR LOOP SHOWS A SHORT WAVE OVER SOUTHERN PENNSYLVANIA LIFTING NORTHEAST...WITH RIDGING OCCURRING ACROSS THE CENTRAL CONUS AHEAD OF THE DEVELOPING SYSTEM OVER THE ROCKIES. ACARS 400-250MB WIND OBSERVATIONS SHOW A 100-140KT ANTICYCLONICALLY CURVED JET FROM THE FOUR CORNERS REGION INTO THE CAROLINAS. 11Z SURFACE ANALYSIS PLACED A 1005MB OCCLUDED CYCLONE NEAR CHARLOTTESVILLE...WITH OCCLUSION FRONT SOUTH TO NEAR ATLANTA. THE BAROCLINIC ZONE RUNS EAST ACROSS THE GULF STATES AND SOUTH CAROLINA. A 1015MB ANTICYCLONE DOMINATES THE GREAT LAKES REGION. SHORT WAVE IS LIFTING NORTHEAST INTO NEW ENGLAND...WITH DRYING SEEN IN THE UPPER LEVELS ON WATER VAPOR IMAGERY. RAIN WILL CONTINUE TO DIMINISH TO AREAS OF SPRINKLES AS A RESULT. KEPT IN A 30 POP FOR THOSE LOCATIONS WHICH MAY RECORD A HUNDRETH OR TWO EARLY THIS AFTERNOON. WINDS BECOME NORTHWESTERLY WITH THE PASSAGE OF THE OCCLUDED BOUNDARY. CLOUDS EXPECTED TO GRADUALLY ERODE FROM SOUTHWEST TO NORTHEAST AS ANTICYCLONIC FLOW ALOFT BEGINS TO SET UP. THIS WILL ALLOW TEMPERATURES IN THE SOUTHWEST TO NEAR 70F...WITH LOCATIONS CLOSER TO THE PA BORDER AND BAY STRUGGLING TO REACH 60F. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... HIGH PRESSURE WILL CONTINUE TO BUILD OVERHEAD TONIGHT IN THE WAKE OF LOW PRESSURE AT THE SURFACE...AND THE UPPER LEVEL DISTURBANCE. SKIES WILL GRADUALLY IMPROVE TO MOSTLY CLEAR/PARTLY CLOUDY AND DRY CONDITIONS ARE ANTICIPATED. SREFS AND NUMERICAL GUIDANCE NOT SHOWING MUCH POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT. HOWEVER...IF THE NW WINDS COMPLETELY DE-COUPLE...SOME PATCHY FOG IS LIKELY...ESPECIALLY WITH THE SATURATED GROUND. OTHERWISE...THE MET NUMBERS LOOKED BETTER FOR THE OVERNIGHT MINS. && .LONG TERM /SUNDAY THROUGH FRIDAY/... SURFACE HIGH WILL MOVE OFF THE COAST SUNDAY AND THE NEXT STORM SYSTEM WILL APPROACH FROM THE WEST. THIS SYSTEM IS ALREADY SHOWING UP ON THE SATELLITE IMAGERY AS IT MOVES INTO THE ROCKIES THIS MORNING. AS THIS SYSTEM TRACKS THROUGH THE PLAINS LATER TODAY AND TONIGHT IT WILL PHASE WITH NORTHERN BRANCH ENERGY FROM CANADA CAUSING THIS SYSTEM TO DEEPEN RAPIDLY. GUIDANCE CONTINUES TO BE IN VERY GOOD AGREEMENT IN BRINGING A CLOSED OFF 500MB LOW THROUGH THE OHIO VALLEY SUNDAY AND ACROSS SOUTHERN VIRGINIA SUNDAY NIGHT BEFORE SLOWLY MOVING OFF THE MID-ATLANTIC COAST MONDAY. THE TRACK OF THIS SYSTEM WILL ALLOW FOR A COASTAL STORM TO DEVELOP JUST OFF THE NORTH CAROLINA COAST BY SUNDAY NIGHT. GIVEN THE STRONG DYNAMICS WITH THE UPPER-LEVEL LOW...THIS WILL BE AN ABNORMALLY STRONG COASTAL SYSTEM FOR THIS TIME OF YEAR. 09Z SREF SHOW SURFACE PRESSURES WITH THE COASTAL LOW BEING AROUND 3 TO 4 STANDARD DEVIATIONS BELOW NORMAL. GIVEN THE STRONG DYNAMICS WITH THE SYSTEM AND THE FAVORED TRACK JUST TO OUR SOUTH. THIS WILL COMBINE WITH PLENTY OF DEEP MOISTURE FROM THE ATLANTIC TO BRING SIGNIFICANT RAINFALL TO THE REGION STARTING LATER SUNDAY AND LASTING THROUGH MONDAY. AS OF NOW IT STILL APPEARS THAT THE HEAVIEST RAIN WILL FALL SUNDAY NIGHT FOR MOST LOCATIONS. GIVEN THE RECENT RAINFALL COMBINED WITH A POTENTIAL OF 1 TO 3 INCHES OF RAIN WITH THIS SYSTEM DOES CAUSE MORE CONCERN FOR RIVER FLOODING AND FLOODING OF SMALL STREAMS AND CREEKS SUNDAY NIGHT INTO EARLY NEXT WEEK. FOR NOW...WILL MENTION IN THE HWO AND HOLD OFF ON A FLOOD WATCH GIVEN THE FACT THAT IT IS STILL 48 HOURS OUT. THE COASTAL STORM WILL SLOWLY DEPART MONDAY AND WINDY CONDITIONS ARE EXPECTED BEHIND IT MONDAY AFTERNOON INTO MONDAY EVENING. HIGH PRESSURE WILL RETURN FOR TUESDAY AND WEDNESDAY BRINGING A RETURN OF DRY CONDITIONS. THE NEXT SYSTEM WILL ARRIVE FOR THE LATTER PART OF THE WEEK WITH THE NEXT CHANCE FOR PRECIPITATION. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... MVFR CEILINGS MID MORNING EXPECTED TO IMPROVE INTO VFR AS MOISTURE FROM THE LASTEST UPPER LEVEL DISTURBANCE MOVES OUT OF THE REGION. WINDS STREGTHEN OUT OF THE NORTH AS HIGH PRESSURE BEGINS TO BUILD IN. WITH SKIES CLEARING AND WINDS BECOMING LIGHT THIS EVENING...WILL HAVE TO MONITOR FOR AREAS OF FOG DEVELOPMENT. VFR CONDITIONS ARE EXPECTED TO START SUNDAY...BUT CONDITIONS WILL DETERIORATE TO MVFR/IFR CIGS AND VSBYS AS THE AFTERNOON PROGRESSES. MORE MVFR/IFR CIGS AND VSBYS ARE EXPECTED SUNDAY NIGHT INTO MONDAY AS A POTENT STORM SYSTEM PASSES JUST SOUTH OF THE TERMINALS. CONDITIONS WILL IMPROVE LATER MONDAY AFTERNOON AND MONDAY NIGHT AS THE STORM SYSTEM DEPARTS...BUT GUSTY NORTH-NORTHWEST WINDS ARE EXPECTED BEHIND THE STORM. HIGH PRESSURE WILL BRING A RETURN OF TRANQUIL CONDITIONS FOR TUESDAY AND WEDNESDAY. && .MARINE... NORTHERLY FLOW INCREASES THIS AFTERNOON AS HIGH PRESSURE BEGINS TO BUILD INTO THE REGION. A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AND SUNDAY NIGHT. SMALL CRAFT WINDS ARE EXPECTED FOR MONDAY INTO TUESDAY AS WELL. DEPENDING ON THE EXACT TRACK AND STRENGTH OF THE STORM...A GALE WARNING MAY BE WARRANTED SOMETIME LATE SUNDAY NIGHT THROUGH MONDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 12 PM SUNDAY TO 6 AM EDT MONDAY FOR ANZ530>537. && $$ SYNOPSIS...LASORSA NEAR TERM...ROGOWSKI SHORT TERM...LISTEMAA LONG TERM...LASORSA AVIATION...ROGOWSKI MARINE...ROGOWSKI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1053 AM EDT FRI MAY 9 2008 .SYNOPSIS... A WEAK AREA OF LOW PRESSURE WILL MOVE THROUGH THE REGION TONIGHT FOLLOWED BY HIGH PRESSURE TO START THE WEEKEND. ANOTHER STORM SYSTEM WILL PASS TO OUR SOUTH LATE SUNDAY AND MONDAY BRINGING ANOTHER CHANCE FOR SIGNIFICANT RAIN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WATER VAPOR LOOP SHOWS A SHORT WAVE AND ASSOCIATED DRY SLOT CROSSING OVER THE MID ATLANTIC. THE NEXT SHORT WAVE IS SLIDING OVER THE MIDDLE MISSISSIPPI RIVER VALLEY. ACARS 400-250MB WIND OBSERVATIONS SHOW A 100-130KT WESTERLY JET OVER THE PLAINS. 10Z SURFACE ANALYSIS PLACED A 1001MB CYCLONE SOUTH OF PETERSBURG...WITH A STATIONARY BOUNDARY EXTENDING NORTHEAST ACROSS CENTRAL MARYLAND AND SOUTHERN NEW JERSEY. THE COLD FRONT STRETCHED SOUTH ALONG THE APPALACHIANS...THEN WEST ACROSS THE GULF STATES. HEAVIEST OF THE PRECIPITATION HAS LIFTED TO THE NORTHEAST AS THE SHORT WAVE PASSES OVERHEAD WITH THE BEST CHANCES REMAINING ALONG THE PENNSYLVANIA BORDER. WITH DRY AIR IMPINGING ALOFT AND STABLE PROFILES IN THE LOWER LEVELS...DO NOT ANTICIPATE ADDITIONAL PRECIPITATION DEVELOPMENT THIS AFTERNOON. WILL HOWEVER HAVE TO MONITOR FOR BREAKS IN THE CLOUDS...ESPECIALLY ACROSS CENTRAL SHENANDOAH VALLEY. 03Z SHORT RANGE ENSEMBLES ALL INDICATE MEAGER CHANCES OF 50 MUCAPE THIS AFTERNOON. COLD FRONT CONTINUES TO SLIDE SOUTHWARD ACROSS THE REGION...WITH GUSTY NORTHERLY FLOW ON THE COOL SIDE. TEMPERATURES WILL STRUGGLE TO RISE ON THE NORTHERN SIDE...BEFORE FALLING MID AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... LOW PRESSURE KICKS OUT TO SEA THIS EVENING...BUT THE MODELS HAVE HAD GOOD CONSISTENCY IN SHOWING AN UPPER TROUGH/SHORTWAVE APPROACHING TONIGHT AND MOVING ACROSS THE AREA ON SATURDAY. THERE ARE MINOR TIMING DIFFERENCES...BUT THE THEME IS FOR AN RE-INCREASE IN RAIN CHANCES FIRST WEST OF THE BLUE RIDGE IN THE EVENING THEN FURTHER EAST AFTER MIDNIGHT INTO SATURDAY. MODELS SHOW A SHORTWAVE RIDGE MOVING ACROSS SATURDAY NIGHT...BUT LIFT AHEAD OF ANOTHER LOW PRESSURE SYSTEM WILL BRING RENEWED CHANCES FOR RAIN SUNDAY...ESPECIALLY DURING THE AFTERNOON. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT WITH THE NEXT STORM SYSTEM TRACKING THROUGH THE OHIO VALLEY SUNDAY NIGHT AND ACROSS SOUTHERN VIRGINIA EARLY MONDAY BEFORE MOVING OFF THE MID-ATLANTIC COAST MONDAY AFTERNOON. WITH THE TRACK OF THE SYSTEM JUST TO THE SOUTH...THIS WOULD PUT MOST OF THE CWA IN THE FAVORED AREA FOR ISENTROPIC LIFT. THIS COMBINED WITH THE FACT THAT THIS IS ANOTHER POTENT STORM SYSTEM WITH PLENTY OF DYNAMICS AND MOISTURE MEANS THAT THERE IS A GOOD CHANCE FOR SIGNIFICANT RAIN. THE BEST CHANCE FOR THE HEAVIEST RAIN APPEARS TO BE SUNDAY NIGHT INTO EARLY MONDAY...BUT TIMING IS STILL A BIT UNCERTAIN GIVEN THE FACT THAT IT IS STILL A COUPLE DAYS OUT. AS OF NOW...THE SEVERE WEATHER THREAT DOES NOT SEEM TOO IMPRESSIVE GIVEN THE FACT THAT A TRACK FURTHER SOUTH WOULD KEEP MOST OF THE INSTABILITY DOWN ACROSS THE CAROLINA`S. HIGH PRESSURE WILL SLOWLY BUILD OVER THE MID-ATLANTIC MONDAY NIGHT AND TUESDAY BRINGING A RETURN OF DRIER CONDITIONS. HIGH PRESSURE WILL MOVE OFF THE COAST WEDNESDAY AND THE NEXT STORM SYSTEM WILL BRING ANOTHER CHANCE FOR PRECIPITATION BY THURSDAY. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... RAIN WILL BE MOVING OUT OF THE REGION MIDDAY AS THE UPPER LEVEL DISTURBANCE PASSES. IFR CEILINGS MID MORNING EXPECTED TO LIFT TO MVFR THIS AFTERNOON WITH DIURNAL CYCLE AND PASSAGE OF A COLD FRONT FROM THE NORTH. NORTHERLY WIND GUSTS UP TO 25KTS WILL DEVELOP THROUGH THE EARLY PORTION OF THE AFTERNOON PUSH. THE NEXT STORM SYSTEM WILL AFFECT THE TERMINALS SUNDAY NIGHT AND MONDAY BRINGING A GOOD CHANCE FOR RAIN ALONG WITH MVFR/IFR CIGS AND VSBYS. HIGH PRESSURE WILL RETURN FOR MONDAY NIGHT AND TUESDAY BRINGING A RETURN OF VFR CONDITIONS. && .MARINE... SMALL CRAFT ADVISORY WILL REMAIN UP THROUGH THIS EVENING. NORTHERLY WIND GUSTS 20-25KTS DEVELOP TODAY AS A COLD FRONT SHIFTS SOUTH ACROSS THE WATERS. A SMALL CRAFT ADVISORY WILL LIKELY BE WARRANTED FOR SUNDAY NIGHT THROUGH MONDAY NIGHT AS ANOTHER STORM SYSTEM PASSES JUST SOUTH OF THE WATERS. && .HYDROLOGY... ISOLATED ROAD CLOSURES DUE TO HIGH WATER EXPECTED TO RECEDE AS RAIN MOVES OUT OF THE REGION. HEAVIEST PRECIPITATION...CORRIDOR OF 2-4 INCHES...OCCURRED ACROSS NORTH CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND LAST NIGHT INTO THIS MORNING. MAIN STEM RIVERS EXPECTED TO CREST UNDER FLOOD STAGE...RAPPAHANNOCK RIVER NEAR REMINGTON IS FORECAST TO CREST A FOOT AND A HALF UNDER FLOOD STAGE THIS EVENING. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ530>537. && $$ SYNOPSIS...LASORSA NEAR TERM...ROGOWSKI SHORT TERM...PELOQUIN LONG TERM...LASORSA AVIATION...ROGOWSKI MARINE...ROGOWSKI HYDROLOGY...ROGOWSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 AM EDT FRI MAY 9 2008 UPDATED FOR THE 12Z TAF ISSUANCE .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ALF TO THE S OF VORTEX CENTERED OVER NW ONTARIO. A WEAK HI PRES RDG IS CENTERED OVER LK SUP...BUT THERE IS QUITE A BIT OF MID/HI CLD STREAMING INTO THE UPR LKS IN ADVANCE OF A SHRTWV MOVING THRU THE NRN PLAINS AND ACCOMPANYING WEAK LO PRES TROF STRETCHING TOWARD WRN LK SUP. 00Z MPX SDNG SHOWS THE HIER MSTR IS CONFINED ABV H8. FARTHER N AND E...THE 00Z INL/GRB SDNGS AS WELL AS THE 23Z TAMDAR SDNG FM DLH ARE QUITE DRY THRU THE ENTIRE TROP. SINCE THE AIRMASS IN PLACE IS SO DRY...RA HAS SO FAR CREPT NO FARTHER N THAN SCNTRL MN/WI. ANOTHER STRONGER HI IS BLDG OVER SCNTRL CAN. THERE IS QUITE A BIT OF SC ALG AND BEHIND THE COLD FNT STRETCHING ACRS FAR NW MN IN ADVANCE OF THIS HI. 00Z YPL/YQD SDNGS SHOW HIER RH AT THE TOP OF THE MIXED LYR BLO SUBSIDENCE INVRN BTWN H75-8. ANOTHER SHRTWV NOTED OVER THE PAC NW MOVING E THRU THE NRN ROCKIES. MAIN FCST CONCERNS THIS PACKAGE ARE CLDS TRENDS/TEMPS INTO SAT... THEN PCPN CHCS LATER IN THE WEEKEND ASSOCIATED WITH THE SYS NOW OVER THE PAC NW. FOR TDAY...SHRTWV NOW OVER THE NRN PLAINS IN SD IS FCST TO DRIFT E ACRS SRN WI...WITH DEEPER MSTR DEPICTED ON THE MPX SDNG REMAINING TO THE S. SINCE THE VORTEX OVER NW ONTARIO IS FCST TO REMAIN NEARLY STNRY AND THE FLOW ALF ZONAL...THE SHARPER THERMAL PACKING AT H85 ASSOCIATED WITH FNT NOW ENTERING NOW MN IS PROGGED TO REMAIN TO THE N. SO WDSPRD SC N OF THE BORDER SHOULD STAY THERE. ONCE MID/HI CLD ASSOCIATED WITH THE SHRTWV MOVING TO THE S SHIFTS TO THE E TDAY... SUSPECT SKIES OVER THE CWA WL TURN MOSUNNY WITH WEAK HI PRES RDG DOMINATING. GIVEN THE DRYNESS OF THE LLVLS ACRS NRN MN AND RISING MSLP...PREFER THE DRIER NAM FCST SDNGS WITH MORE NNW WIND TO THE MOISTER GFS WITH LIGHTER WINDS/LESS DRY ADVCTN. MIXING TO H75 ON INL SDNG/ NAM FCST SDNGS SUG HI TEMPS WL REACH 55 TO 60 OVER THE INTERIOR AWAY FM THE COOLING INFLUENCE OF THE GRT LKS. GOING FCST HI TEMPS NEED LTL MODIFICATION. WEAK PRES GRADIENT/ INLAND HTG INDICATE LK BREEZES WL DVLP AND KEEP COASTAL LOCATIONS COOLER... ESPECIALLY DOWNWIND OF LK SUP WITH SYNOPTIC SCALE NNW WIND. EXPECT DRY WX TNGT WITH SFC HI PRES PASSING SLOWLY TO THE S. AS THE HI CENTER MOVES TOWARD THE LOWER LKS...NAM SHOWS RETURN SW FLOW WITH SOME ISENTROPIC LIFT ON THE 290K SFC (H75-8) DVLPG OVER WRN ZNS AFT 06Z. GFS IS A BIT LESS AGGRESSIVE WITH THE ISENTROPIC LIFT WITH WEAKER SFC PRES FALLS OVER THE NRN PLAINS/WEAKER RETURN FLOW. WL MAINTAIN GOING FCST IDEA OF SOME AC SPRDG W-E DURING THE NGT. LACK OF OTHER DYNAMICS/RATHER SHALLOW LYR OF MOISTENING OF ANTECEDENT DRY AIRMASS SUGS THERE WL BE NO PCPN. EXPECT THE LOWEST TEMPS OVER THE INTERIOR E AND SCNTRL...WHERE ANY CLD WL NOT ARRIVE UNTIL LATER. ON SAT...SHRTWV OVER THE PAC NW IS FCST TO MOVE INTO THE NRN PLAINS...WITH INVERTED TROF TO THE NE OF ACCOMPANYING SFC LO EXTENDING INTO WRN UPR MI. NAM GENERATES SOME PCPN OVER ALL BUT THE ERN ZNS DURING THE 18Z-24Z PD...WHILE GFS IS A BIT LESS AGGRESSIVE BUT HAS PCPN FALLING TOWARD 00Z OVER THE FAR W AND THE WI BORDER. BOTH MODELS SHOW THE WRN FA WL FALL INTO THE RRQ OF 100KT H3 JET MAX IN CONFLUENCE ZN OVER ONTARIO AND ASSOCIATED UPR DVGC. CONSIDERING THE DRY LLVLS SHOWN BY THE NAM FCST SDNGS...THE PLACEMENT OF THE UPR DVGC ACRS ONLY THE W...AND NCEP PREFERENCE FOR THE SFC LO TO BE FARTHER S SIMILAR TO THE GFS...WL TREND TOWARD THE SOMEWHAT DRIER GFS/00Z UKMET FCST. WL MAKE ONLY MINOR MODIFICATIONS TO GOING FCST TO EXPAND SCHC POPS JUST A BIT FARTHER INTO THE WRN FA. AS THE SHRTWV/SFC LO TRACK EWD SAT NGT...NAM/GFS/UKMET GENERATE PCPN OVER MAINLY THE W HALF OF THE FA NEAR WEAK INVERTED TROF TO THE N OF MAIN LO PRES CENTER WELL TO THE S. WL AGAIN TREND TOWARD THE LIGHTER PCPN FCST OF THE GFS/UKMET AS NCEP FAVORS HIER MSLP OVER THE UPR LKS IN LINE WITH THOSE FCSTS AND PLACEMENT OF LOWER PRES CLOSER TO MAIN HGT FALLS ACCOMPANYING SHRTWV. GOING FCST POPS LOOK TO BE IN PRETTY GOOD SHAPE...MAIN CHG WAS TO DROP POPS OVER LUCE COUNTY WHERE GFS/ NAM FCST SDNGS APPEAR PROHIBITIVELY DRY SO FAR E OF INVERTED TROF AND WHERE LLVL ENE FLOW OUT OF ONTARIO WL HOLD IN DRIER AIR. DROPPED POPS A LTL FASTER ON SUN/SUN NGT WITH FASTER PROGRESSION OF DRYING ALF W-E AS DEPICTED BY GFS AND ESPECIALLY THE UKMET. LOWERED FCST MIN TEMPS OVER THE W HALF SUN NGT TO ACCOUNTY FOR QUICKER DRYING ALF AND LGT WINDS UNDER SFC HI PRES BLDG OVHD UNDER RISING HGTS IN WAKE OF SHRTWV TO THE S MOVING INTO THE MID ATLANTIC. FINAL CHG WAS TO SLOW EWD PROGRESSION OF PCPN ON MON WITH 00Z GFS/ECMWF SHOWING H5 RDGING HANGING IN OVER THE LKS BTWN DEEP TROFS OVER THE E AND W. COORDINATED WITH APX/GRB/DLH/LOT. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... DRIER AIR WILL BE THE RULE AS HIGH PRESSURE DOMINATES...WITH VFR CONDITIONS THROUGH THE PERIOD. DEPENDING OF THE LOCATION OF AN APPROACHING FRONTAL BOUNDARY...THERE ARE INDICATIONS THAT LOW VFR CEIGS WILL OCCUR AFTER 06Z...MAINLY AT CMX AND AFTER 09Z AT SAW. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... THE AREA WILL BE INFLUENCED BY 2 LOW PRESSURE SYSTEM DURING THIS PERIOD. THE FIRST WILL PASS JUST SOUTH OF LAKE MICHIGAN SATURDAY NIGHT...WHILE THE SECOND IS EXPECTED TO MOVE OVER LAKE SUPERIOR TUESDAY AFTERNOON AND EVENING. WINDS BELOW 20KT WILL BE COMMON OVER MOST OF THE PERIOD. THE STRONGEST WINDS SHOULD BE LATE SATURDAY IN RESPONSE THE THE FIRST LOW WITH NNE WINDS FUNNELING ACROSS THE WEST AND STEADY NORTH OVER EAST CENTRAL AREAS...AND THEN STRONGER AGAIN OUT OF THE SOUTH TUESDAY MORNING AHEAD OF THE NEXT LOW (AT OR LESS THAN 30KT IN BOTH INSTANCES). && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...KC AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
405 AM EDT FRI MAY 9 2008 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ALF TO THE S OF VORTEX CENTERED OVER NW ONTARIO. A WEAK HI PRES RDG IS CENTERED OVER LK SUP...BUT THERE IS QUITE A BIT OF MID/HI CLD STREAMING INTO THE UPR LKS IN ADVANCE OF A SHRTWV MOVING THRU THE NRN PLAINS AND ACCOMPANYING WEAK LO PRES TROF STRETCHING TOWARD WRN LK SUP. 00Z MPX SDNG SHOWS THE HIER MSTR IS CONFINED ABV H8. FARTHER N AND E...THE 00Z INL/GRB SDNGS AS WELL AS THE 23Z TAMDAR SDNG FM DLH ARE QUITE DRY THRU THE ENTIRE TROP. SINCE THE AIRMASS IN PLACE IS SO DRY...RA HAS SO FAR CREPT NO FARTHER N THAN SCNTRL MN/WI. ANOTHER STRONGER HI IS BLDG OVER SCNTRL CAN. THERE IS QUITE A BIT OF SC ALG AND BEHIND THE COLD FNT STRETCHING ACRS FAR NW MN IN ADVANCE OF THIS HI. 00Z YPL/YQD SDNGS SHOW HIER RH AT THE TOP OF THE MIXED LYR BLO SUBSIDENCE INVRN BTWN H75-8. ANOTHER SHRTWV NOTED OVER THE PAC NW MOVING E THRU THE NRN ROCKIES. MAIN FCST CONCERNS THIS PACKAGE ARE CLDS TRENDS/TEMPS INTO SAT... THEN PCPN CHCS LATER IN THE WEEKEND ASSOCIATED WITH THE SYS NOW OVER THE PAC NW. FOR TDAY...SHRTWV NOW OVER THE NRN PLAINS IN SD IS FCST TO DRIFT E ACRS SRN WI...WITH DEEPER MSTR DEPICTED ON THE MPX SDNG REMAINING TO THE S. SINCE THE VORTEX OVER NW ONTARIO IS FCST TO REMAIN NEARLY STNRY AND THE FLOW ALF ZONAL...THE SHARPER THERMAL PACKING AT H85 ASSOCIATED WITH FNT NOW ENTERING NOW MN IS PROGGED TO REMAIN TO THE N. SO WDSPRD SC N OF THE BORDER SHOULD STAY THERE. ONCE MID/HI CLD ASSOCIATED WITH THE SHRTWV MOVING TO THE S SHIFTS TO THE E TDAY... SUSPECT SKIES OVER THE CWA WL TURN MOSUNNY WITH WEAK HI PRES RDG DOMINATING. GIVEN THE DRYNESS OF THE LLVLS ACRS NRN MN AND RISING MSLP...PREFER THE DRIER NAM FCST SDNGS WITH MORE NNW WIND TO THE MOISTER GFS WITH LIGHTER WINDS/LESS DRY ADVCTN. MIXING TO H75 ON INL SDNG/ NAM FCST SDNGS SUG HI TEMPS WL REACH 55 TO 60 OVER THE INTERIOR AWAY FM THE COOLING INFLUENCE OF THE GRT LKS. GOING FCST HI TEMPS NEED LTL MODIFICATION. WEAK PRES GRADIENT/ INLAND HTG INDICATE LK BREEZES WL DVLP AND KEEP COASTAL LOCATIONS COOLER... ESPECIALLY DOWNWIND OF LK SUP WITH SYNOPTIC SCALE NNW WIND. EXPECT DRY WX TNGT WITH SFC HI PRES PASSING SLOWLY TO THE S. AS THE HI CENTER MOVES TOWARD THE LOWER LKS...NAM SHOWS RETURN SW FLOW WITH SOME ISENTROPIC LIFT ON THE 290K SFC (H75-8) DVLPG OVER WRN ZNS AFT 06Z. GFS IS A BIT LESS AGGRESSIVE WITH THE ISENTROPIC LIFT WITH WEAKER SFC PRES FALLS OVER THE NRN PLAINS/WEAKER RETURN FLOW. WL MAINTAIN GOING FCST IDEA OF SOME AC SPRDG W-E DURING THE NGT. LACK OF OTHER DYNAMICS/RATHER SHALLOW LYR OF MOISTENING OF ANTECEDENT DRY AIRMASS SUGS THERE WL BE NO PCPN. EXPECT THE LOWEST TEMPS OVER THE INTERIOR E AND SCNTRL...WHERE ANY CLD WL NOT ARRIVE UNTIL LATER. ON SAT...SHRTWV OVER THE PAC NW IS FCST TO MOVE INTO THE NRN PLAINS...WITH INVERTED TROF TO THE NE OF ACCOMPANYING SFC LO EXTENDING INTO WRN UPR MI. NAM GENERATES SOME PCPN OVER ALL BUT THE ERN ZNS DURING THE 18Z-24Z PD...WHILE GFS IS A BIT LESS AGGRESSIVE BUT HAS PCPN FALLING TOWARD 00Z OVER THE FAR W AND THE WI BORDER. BOTH MODELS SHOW THE WRN FA WL FALL INTO THE RRQ OF 100KT H3 JET MAX IN CONFLUENCE ZN OVER ONTARIO AND ASSOCIATED UPR DVGC. CONSIDERING THE DRY LLVLS SHOWN BY THE NAM FCST SDNGS...THE PLACEMENT OF THE UPR DVGC ACRS ONLY THE W...AND NCEP PREFERENCE FOR THE SFC LO TO BE FARTHER S SIMILAR TO THE GFS...WL TREND TOWARD THE SOMEWHAT DRIER GFS/00Z UKMET FCST. WL MAKE ONLY MINOR MODIFICATIONS TO GOING FCST TO EXPAND SCHC POPS JUST A BIT FARTHER INTO THE WRN FA. AS THE SHRTWV/SFC LO TRACK EWD SAT NGT...NAM/GFS/UKMET GENERATE PCPN OVER MAINLY THE W HALF OF THE FA NEAR WEAK INVERTED TROF TO THE N OF MAIN LO PRES CENTER WELL TO THE S. WL AGAIN TREND TOWARD THE LIGHTER PCPN FCST OF THE GFS/UKMET AS NCEP FAVORS HIER MSLP OVER THE UPR LKS IN LINE WITH THOSE FCSTS AND PLACEMENT OF LOWER PRES CLOSER TO MAIN HGT FALLS ACCOMPANYING SHRTWV. GOING FCST POPS LOOK TO BE IN PRETTY GOOD SHAPE...MAIN CHG WAS TO DROP POPS OVER LUCE COUNTY WHERE GFS/ NAM FCST SDNGS APPEAR PROHIBITIVELY DRY SO FAR E OF INVERTED TROF AND WHERE LLVL ENE FLOW OUT OF ONTARIO WL HOLD IN DRIER AIR. DROPPED POPS A LTL FASTER ON SUN/SUN NGT WITH FASTER PROGRESSION OF DRYING ALF W-E AS DEPICTED BY GFS AND ESPECIALLY THE UKMET. LOWERED FCST MIN TEMPS OVER THE W HALF SUN NGT TO ACCOUNTY FOR QUICKER DRYING ALF AND LGT WINDS UNDER SFC HI PRES BLDG OVHD UNDER RISING HGTS IN WAKE OF SHRTWV TO THE S MOVING INTO THE MID ATLANTIC. FINAL CHG WAS TO SLOW EWD PROGRESSION OF PCPN ON MON WITH 00Z GFS/ECMWF SHOWING H5 RDGING HANGING IN OVER THE LKS BTWN DEEP TROFS OVER THE E AND W. COORDINATED WITH APX/GRB/DLH/LOT. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... VFR CONDITIONS WILL PERSIST AT KCMX/KSAW THRU THIS FCST PERIOD AS HIGH PRES LINGERS OVER THE AREA. CLOUD COVER WILL GENERALLY BE ABOVE 8KFT AND SHOULD THIN OUT FRI AFTN/EVENING. DRIER AIRMASS OVER THE AREA SUGGESTS MUCH LESS CUMULUS DEVELOPMENT THIS AFTN COMPARED TO THU AFTN. IN FACT...THERE MAY BE NO CUMULUS AT ALL. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... THE AREA WILL BE INFLUENCED BY 2 LOW PRESSURE SYSTEM DURING THIS PERIOD. THE FIRST WILL PASS JUST SOUTH OF LAKE MICHIGAN SATURDAY NIGHT...WHILE THE SECOND IS EXPECTED TO MOVE OVER LAKE SUPERIOR TUESDAY AFTERNOON AND EVENING. WINDS BELOW 20KT WILL BE COMMON OVER MOST OF THE PERIOD. THE STRONGEST WINDS SHOULD BE LATE SATURDAY IN RESPONSE THE THE FIRST LOW WITH NNE WINDS FUNNELING ACROSS THE WEST AND STEADY NORTH OVER EAST CENTRAL AREAS...AND THEN STRONGER AGAIN OUT OF THE SOUTH TUESDAY MORNING AHEAD OF THE NEXT LOW (AT OR LESS THAN 30KT IN BOTH INSTANCES). && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...KC AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION
NWS DULUTH MN
615 PM CDT SAT MAY 10 2008 .UPDATE... ADDED SNOW TO THE FORECAST FOR THE EARLY EVENING HOURS IN THE NORTHWEST CWA AS A VERY NARROW BAND OF FRONTOGENESIS AND COLUMN COOLING HAS LED TO SNOW PUSHING IN FROM THE WEST. BEMIDJI HAS TURNED BACK OVER TO RAIN...BIGFORK REMAINS AS SNOW AT 600 PM. TAMDAR SOUNDINGS INDICATE THE POTENTIAL FOR SNOW TO CONTINUE FOR A FEW HOURS. && .PREV DISCUSSION... /ISSUED 310 PM CDT SAT MAY 10 2008/ DISCUSSION... CURRENT SFC ANALYSIS INCLUDES A SFC LOW IN THE CEN PLAINS WITH A SECONDARY LOW IN SE SODAK. AN INVERTED EXTENDS NE FROM THE LOW OVER SW MN...THROUGH THE TWIN CITIES METRO...AND OVER WRN LAKE SUPERIOR. MOSAIC RADAR IMAGERY DEPICTS A LARGE SWATH OF RA ENCOMPASSING THE SRN TWO THIRDS OF MN. AS OF 3 PM...THE LEADING EDGE OF THE RA IS ALONG A LINE FROM KFOZ...TO KHZX...KMZH...AND KRZN. GRADUALLY WORKING NEWRD THROUGH THE FA. MEANWHILE...AN UPR LVL TROUGH AND ELONGATED VORT MAX SEEN ON WV IMAGERY HAS SWEEP SE INTO NODAK AND NW MN. EXPECTING THE RA TO INCREASE IN COVERAGE AND INTENSITY THIS EVENING. BY 03Z...THE UPR LVL TROUGH AND CORRIDOR STRONG 2D-FGEN...BECOME CO-LOCATED WITH THE SFC FEATURE...ALLOWING FOR ADDITIONAL RA DEVELOPMENT. THE NW ZONES...INCLUDING KINL TO KFOZ...WILL BE ON THE BACK EDGE OF THE FORCING AND CAN EXPECT SCT TO ISOLD -SHRA MAINLY THIS EVENING. SEVERAL SHORT TERM FCST CHALLENGES. FIRST BEING OVERNIGHT POPS/QPF. HIGH CONFIDENCE IN MOST AREAS WILL RECEIVING ACCUMULATING PCPN. HOWEVER...THE LIMITING FACTOR ON P-AMOUNTS WILL BE THE SIGNIFICANT LACK OF MOISTURE...MAINLY IN THE WIS ZONES. THE RA WAS MUCH SLOWER THAN EXPECTED TO MOVE THIS AFTN DUE TO THE DRY BDRY LAYER IN PLACE. AT 20Z...SFC DEW POINT DEPRESSIONS WERE ON THE ORDER OF 10-20 F ACROSS NE MN AND UPWARDS OF 30 F IN NRN WIS. BUFR SOUNDINGS SHOWING PWATS ONLY REACHING FROM 0.5 IN AT INL TO 0.6-0.8 ELSEWHERE OVERNIGHT. CUTBACK QPF...EXPECTING MOST AREAS TO RECEIVE 0.25-0.5 IN THROUGH WED MORNING. HIGHER AMOUNTS MAY BE FOUND IN THE ARROWHEAD. THE NAM IS HANDLING THE DRY AIR AND LAG TO SATURATE THE BEST...SO WENT NEAR BUFR SOUNDINGS AND NAME RH FIELDS FOR THE ONSET/EXIT TIMING OF THE QPF AND CLOUD COVER TONIGHT AND SUN. NEXT CHALLENGE IN P-TYPE LATE TONIGHT. SOUNDINGS SUGGEST TEMPS STAY WARM ENOUGH FOR ALL RA UNTIL THE CLOUDS SHIELD BREAKS UP AND AXIS OF COOLEST AIR MOVES OVERHEAD DROPPING TEMPS SUB-FREEZING. HOWEVER...THE BEST FORCING IS FOUND IN THE IRON RANGE/ARROWHEAD REGION AFT 06Z...SO -SN MIXING WITH THE RA IS A POSSIBILITY. THE NAM/GFS/ECM ALL SHOW 1000-500 MB THICKNESSES FALLING TO 530 DAM BY 12S OVER THIS AREA AS WELL. LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. FOCUS TURNS NEXT TO A STRONG SYSTEM THAT WILL SWEEP A STRONG COLD FRONT OVER THE REGION...BRINGING A TSTM THREAT FOR THE MON/TUES TIME FRAME. MODELS DISAGREE ON THE TIMING AND LOCATION OF BEST FORCING ATTM...BUT ALL AGREE THAT THE COLD FRONT BRINGS ANOTHER COOL DOWN WITH 850 MB TEMPS BLW 0 C BY MID WEEK. AVIATION...RAIN WILL CONTINUE TO SPREAD INTO NORTHEAST MINNESOTA...AND OVER NORTHWEST WISCONSIN TONIGHT. THE RAIN WILL BE MOST WIDESPREAD FROM THE BRAINERD LAKES AREAS...NORTHEAST TOWARD THE TWIN PORTS. THERE MAY BE SOME SNOW THAT MIXES IN WITH THE RAIN...MAINLY TOWARD INTERNATIONAL FALLS...BIGFORK...DOWN TOWARD PINE RIVER. MVFR...WITH SOME LOCALIZED IFR...CONDITIONS WILL OCCUR OVER MOST OF THE REGION TONIGHT. THE PRECIPITATION AND LOWER CEILINGS WILL DIMINISH FROM WEST TO EAST ACROSS MINNESOTA AND NORTHWEST WISCONSIN LATER TONIGHT OR DURING THE DAY SUNDAY AS THE LOW MOVES EAST. && POINT TEMPS/POPS... DLH 36 51 30 56 / 80 30 10 10 INL 27 57 29 56 / 20 10 10 20 BRD 34 56 37 61 / 90 10 10 10 HYR 36 53 29 63 / 80 60 10 10 ASX 37 50 30 62 / 70 60 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ KD/GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1209 PM CDT SAT MAY 10 2008 .UPDATE...FOR 18Z AVIATION DISCUSSION BELOW && .DISCUSSION.../ISSUED 246 AM CDT SAT MAY 10 2008/ FORECAST CHALLENGES STILL CENTERED ON RAIN EVENT TODAY AND INTO TOMORROW. UPPER TROUGH VERY EVIDENT IN WATER VAPOR IMAGERY OVER THE NORTHERN ROCKIES THIS MORNING...WITH LOOP CLEARLY SHOWING THAT IT IS STILL DIGGING/DEEPENING. MOISTURE PLUME SEEN STREAMING INTO THE NORTHERN PLAINS AND INTO WESTERN MINNESOTA/IOWA IN ADVANCE OF THE TROUGH. NEAREST ECHOES ON THE 88D MOSAIC...IN THE WARM ADVECTION REGIME AHEAD OF THE TROUGH...SEEN IN CENTRAL SOUTH DAKOTA NEAR PIERRE. MODEL PROGS STILL SHOW THE BULK OF THIS DEVELOPING/ENTERING WESTERN MINNESOTA AROUND 12Z /PER 295K ISENTROPIC SURFACE/...AND SPREADING EASTWARD THROUGH THE MORNING HOURS. IT MAY TAKE AWHILE FOR LOCATIONS IN WEST CENTRAL WISCONSIN TO SEE ANY MEASURABLE RAINFALL...WITH LATEST TAMDAR SOUNDINGS AND THE 00Z KMPX RAOB SHOWING A LOT OF DRY AIR IN THE LOW LEVELS. ONLY MINOR TWEAKS WERE MADE TO THE INHERITED FORECAST...WITH LATEST MODEL RUNS AND OBSERVATIONS SUPPORTIVE OF THE DEPICTED TIMING...AND POPS ALREADY VERY HIGH. AS THE SURFACE LOW DEEPENS ON ITS TREK THROUGH THE MID MISSISSIPPI VALLEY...PARTS OF SOUTHERN MINNESOTA...ESPECIALLY...SHOULD SEE BREEZY CONDITIONS TONIGHT. SPEEDS SHOULD REMAIN BELOW ADVISORY CRITERIA...HOWEVER. THINGS BEGIN TO DRY OUT FROM WEST TO EAST LATE TONIGHT /AFTER MIDNIGHT/ AS THE UPPER LOW MOVES TOWARD THE OHIO VALLEY...TAKING ITS WRAPAROUND MOISTURE WITH IT. WITH SUCH UNSEASONABLY COOL AIR SPILLING INTO THE AREA BEHIND THE TROUGH...KEPT THE MENTION OF A RAIN/SNOW MIX FOR PARTS OF WESTERN MINNESOTA AFTER MIDNIGHT TONIGHT. IT STILL LOOKS LIKE THE FORECAST AREA SHOULD BE RAIN FREE BY SUNDAY NIGHT...AS THE SURFACE RIDGE BUILDS IN. BENEATH THE HIGH PRESSURE...TEMPERATURES WILL STILL BE WELL BELOW SEASONAL NORMALS...DESPITE SOME RETURN FLOW LATE IN THE DAY OVER WESTERN MINNESOTA. BY THE BEGINNING OF THE WORK WEEK...OUR NEXT SYSTEM IS KNOCKING ON OUR DOORSTEP...LEADING TO STRONG WARMING ON MONDAY...AND MORE SEASONAL HIGHS. MODELS GENERALLY AGREE ON BRINGING THE COLD FRONT THROUGH NORTHWEST MINNESOTA...AND NEAR THE FORECAST AREA...BY TUESDAY MORNING. GREATER THREAT OF THUNDER WILL ACCOMPANY THIS SYSTEM...WITH HIGHER DEW POINTS/INSTABILITY EXPECTED. REDUCED POPS ON THE WESTERN EDGE FROM TUESDAY NIGHT AND INTO WEDNESDAY...WITH MODELS DEPICTING A MORE RAPID FRONTAL PASSAGE. && .AVIATION.../18Z TAF ISSUANCE/ RAIN SHOWERS WILL OVERSPREAD THE TAF SITES THIS AFTERNOON...AS A SURFACE TROUGH MOVES ACROSS THE CENTRAL PLAINS/MS VALLEY REGIONS. VFR CONDITIONS WILL GRADUALLY DEGRADE TO THE MVFR CATEGORY THIS AFTERNOON AND EVENING...AS SUPPORTED BY THE SREF 70-80 PERCENT PROBABILITIES OF CIG HEIGHTS BELOW 1K/3K FEET. ALSO EXPECT PERIODIC CIG DIPS INTO THE IFR CATEGORY...MAINLY AROUND/AFTER 20Z- 22Z AT KAXN/KRWF/KSTC. THE RAIN SHOWERS SHOULD COME TO AN END AROUND MIDNIGHT AT KAXN/KRWF/KSTC...AND BY DAYBREAK AT KMSP/KRNH/KEAU. LOW LEVEL RELATIVE HUMIDITY PROGS INDICATE MOISTURE WILL LINGER AT KMSP/KRNH/KEAU ON SUNDAY MORNING...SO SCT- BKN CLOUDS HAVE BEEN MAINTAINED THERE THROUGH 18Z. AS THE PRESSURE GRADIENT TIGHTENS ON SUNDAY IN THE WAKE OF THE LOW...NORTHERLY SURFACE WINDS GUSTING TO AROUND 20 KNOTS ARE EXPECTED. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ LS/KAT
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1124 AM MDT SAT MAY 10 2008 .UPDATE... STRONG UPPER LEVEL WINDS CONTINUE ACROSS THE WIND ADVISORY AREA... AND SOME OF THIS MOMENTUM IS REACHING THE SURFACE. MODELS SUGGEST THAT THE STRONGEST SPEEDS WILL OCCUR BETWEEN NOW AND 21Z...WITH A GRADUAL WEAKENING TREND THEREAFTER. A FEW AREAS BORDERING THE WIND ADVISORY MAY BRIEFLY HIT CRITERIA EARLY/MID-AFTERNOON...BUT OPTED TO NOT EXPAND THE ADVISORY FOR SUCH A MINIMAL THREAT. 700MB WINDS WILL DROP TO AROUND 20-30 KNOTS BY 00Z...THUS THE EXPIRATION TIME LOOKS REASONABLE. UPDATED NPWABQ HAS ALREADY BEEN SHIPPED. DPORTER && .PREV DISCUSSION...258 AM MDT SAT MAY 10 2008... WATER VAPOR LOOP THIS MORNING SHOWS A SQUEEZE PLAY IN THE UPPER ATMOSPHERE AS A SOUTHERN STREAM UPPER WAVE OVER NM SHEARS EAST WHILE ANOTHER STRONGER WAVE SLIDES EAST ACROSS THE CENTRAL ROCKIES. THE RESULT IS A 120-140 KNOT JET CORE STRETCHING FROM SW NM NE INTO EASTERN KS AS EVIDENT ON THE 400-250MB ACARS PLOT. AT THE SURFACE A 997MB LOW PRESSURE CENTER IS CENTERED OVER SE CO WITH A COOL FRONT MOVING SOUTH OVER THE FRONT RANGE. 00Z MODEL SUITE...INCLUDING THE UKMET/ECMWF/GFS/NAM/GEM...INDICATE THE SURFACE FRONT WILL SHIFT SE INTO OK WHILE THE MID LEVEL FRONT ASSOCIATED WITH THE CENTRAL ROCKIES UPPER WAVE ALSO PUSHES SE ACROSS NM. THIS WILL ESSENTIALLY COOL MAX TEMPS A FEW DEGREES OVER FRIDAY OVER THE EASTERN PLAINS. SINCE HIGH CLOUDS WILL PUSH WELL EAST OF THE AREA TODAY THERE WILL LIKELY BE SIMILAR TEMPS ACROSS THE WEST AS HEATING BALANCES WEAK COLD AIR ADVECTION AT 700MB. EXPANDED RED FLAG WARNINGS INTO THE NW AND WESTERN MTNS AS WELL AS THE RIO GRANDE VALLEY WITH NW FLOW PATTERN USUALLY STRONGER THAN MOS NUMBERS IN THESE AREAS. AS HIGH PRESSURE BUILDS ACROSS TEXAS SATURDAY NIGHT THE FRONTAL BOUNDARY WILL CONTINUE PUSHING WEST TOWARD THE RIO GRANDE VALLEY THROUGH SUNDAY MORNING. LIGHT/MODERATE EAST CANYON WINDS STILL POSSIBLE IN THE RIO GRANDE VALLEY SUNDAY MORNING. LOW LEVEL RH FIELDS SHOW THERE WILL BE A STRONG DENSITY GRADIENT ALONG THE CENTRAL MTNS WITH THE FRONT THEREFORE LEFT GRIDS UNTOUCHED. THE REMAINDER OF SUNDAY IS EXPECTED TO BE PLEASANT STATEWIDE. BIG CHANGES POSSIBLE EARLY NEXT WEEK AS A STRONG UPPER LEVEL LOW DEVELOPS OVER THE GREAT BASIN. STRONG WINDS AND CRITICAL FIRE WEATHER APPEAR LIKELY FOR MONDAY STATEWIDE. CONCERNED WITH THE TIMING AND INTENSITY OF THIS SYSTEM SINCE 21Z SREF/18Z MREF GUIDANCE SHOWING THE GREATEST UNCERTAINTY WITH REGARD TO 500MB HEIGHT FIELD EXISTS ON THE BACK EDGE OF THE UPPER LOW DEVELOPMENT MONDAY INTO TUESDAY. AT THIS TIME IT APPEARS THE SYSTEM MAY DIG FARTHER SOUTH INTO ARIZONA EARLY TUESDAY AND SLOW ITS PROGRESSION EASTWARD THROUGH WEDNESDAY. THIS WOULD BE IN RESPONSE TO THE DEEP AREA OF LOW PRESSURE DEVELOPING OFF THE EAST COAST ALLOWING FOR STRONGER HEIGHT RISES OVER THE CENTRAL PLAINS THUS INCREASING THE MERIDIONAL FLOW ACROSS THE CONUS. WITH REGARD TO GRID CHANGES DECIDED TO GO ABOVE GUIDANCE MAX TEMPS MONDAY AND TUESDAY...DELAY PRECIP ONSET OVER THE WEST TUESDAY...PUSH HIGHEST POPS INTO THE CENTRAL PORTION OF THE STATE WEDNESDAY. GUYER .AVIATION... SURFACE COOL FRONT APPROACHING NORTHERN NEW MEXICO BORDER AT 09Z SATURDAY WILL CONTINUE TO PUSH SOUTH AND EASTWARD THROUGH THE STATE THROUGH 21Z SATURDAY. AT THE SAME TIME...SHORT WAVE TROUGH TO SWING THROUGH E COLORADO AND WILL BRUSH NORTHCENTRAL/NORTHEAST NEW MEXICO INCREASING WEST TO NORTHWEST GRADIENT ALOFT. THESE FEATURES WILL RESULT IN GUSTY WEST TO NORTHWEST WINDS MOST LOCALES THROUGH 00Z SUNDAY. OTRW ISOLD BRIEF MVFR/IFR CIGS/VSBY IN SHOWERS NEAR THE COLORADO BORDER POSSIBLE THROUGH 21Z. NEXT AVIATION DISCUSSION SCHEDULED FOR 21Z. && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ101>108. WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR THE FOLLOWING ZONES... NMZ011-012. && $$ 46
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
249 AM MDT FRI MAY 9 2008 .DISCUSSION... 08Z SURFACE ANALYSIS SHOWS A 1005MB LOW PRESSURE CENTER OVER EAST CENTRAL NM WITH A REMNANT FRONTAL BOUNDARY DRAPED FROM THE EASTERN SLOPES OF THE SANGRES INTO NORTH CENTRAL TX. WATER VAPOR LOOP SHOWS A WEAK UPPER WAVE SLIDING EAST INTO THE NORTHERN BAJA CALIFORNIA WITH PLENTIFUL UPPER LEVEL MOISTURE ADVECTING NE INTO NM. 400-250MB AIRCRAFT WIND PLOT SHOWS THE RIGHT ENTRANCE REGION OF A 100-120 KNOT JET OVER THE SOUTHERN HALF OF NM. THIS JET WILL ALLOW HIGH CLOUDS TO SPILL OVER NM TODAY...INDICATED WELL BY THE 00Z GFS. 21Z SREF/00Z GFS GUIDANCE SHOW THE 1005MB SURFACE LOW PRESSURE CENTER WILL DEEPEN TO 999MB WHILE LIFTING NE INTO SE CO LATE TODAY. MODEL 700MB PRESSURE GRADIENT STRENGTHENS LATE DAY AS WELL THEREFORE HAVE SIDED WITH NO WIND HIGHLIGHTS GIVEN BEST MIXING POTENTIAL WILL BE TOO LATE. PUSHED RED FLAG WARNING 1 HOUR LATER FOR TODAY...UPGRADED NW CORNER...AND ISSUED ANOTHER FIRE WEATHER WATCH ALL ZONES FOR SATURDAY. MEANWHILE... TWO WEAK PAIRED UPPER WAVES OVER THE NORTHERN ROCKIES WILL PUSH SE INTO THE CENTRAL ROCKIES THIS AFTERNOON LIFTING THE CORE OF THE UPPER JET NORTHWARD OVER SE CO. DECIDED TO REMOVE POPS FROM THE NORTHERN TIER TODAY AND TONIGHT AS BEST DYNAMICS REMAIN IN COLORADO. LOWERED POPS OVER THE NE PLAINS AND SANGRES FOR SATURDAY AS WELL SINCE MODEL 850-700MB MOISTURE FIELD REMAINS BELOW 50 PERCENT AND LOW LEVEL WIND FLOW APPEARS MORE DOWNSLOPE THAN PREVIOUS RUNS BEHIND THE PAIRED UPPER WAVES. DRY FRONTAL BOUNDARY WILL MOVE SW THROUGH THE E PLAINS SATURDAY BRINGING SLIGHTLY COOLER TEMPS TO THE REGION AND THEN A POSSIBLE LIGHT/MODERATE EAST CANYON WIND AT KABQ SUNDAY MORNING. 1015MB SURFACE HIGH PRESSURE BUILDING OVER TEXAS SUNDAY WILL ALLOW FOR WEAK RETURN SE FLOW OVER THE E PLAINS THROUGH MONDAY WHILE AN UPPER WAVE ATTEMPTS TO DEEPEN OVER THE GREAT BASIN. DRY SW FLOW IN THIS REGIME WILL CREATE MORE FIRE WEATHER CONCERNS MONDAY AND TUESDAY. EXTENDED ENSEMBLE GUIDANCE SHOWS BETTER AGREEMENT WITH THE DEVELOPMENT OF A STRONG UPPER LEVEL FEATURE EARLY NEXT WEEK OVER THE DESERT SW HOWEVER THE TIMING IS STILL IN QUESTION. GUYER && .AVIATION... VFR CONDITIONS PREVAIL ALL AIRPORTS NEXT 24 HOURS. SOUTHWEST WINDS WILL GUST TO AROUND 35KT BTWN 21Z AND 03Z. NEXT AVIATION DISCUSSION SCHEDULED FOR 21Z. CHJ && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 77 43 72 38 / 0 0 0 0 GALLUP.......................... 73 36 72 31 / 0 0 0 0 GRANTS.......................... 74 39 73 29 / 0 0 0 0 GLENWOOD........................ 81 42 82 44 / 0 0 0 0 CHAMA........................... 70 34 65 30 / 0 5 5 0 LOS ALAMOS...................... 72 40 70 36 / 0 0 0 0 RED RIVER....................... 64 32 60 29 / 0 5 10 0 TAOS............................ 70 37 69 31 / 0 0 5 0 SANTA FE........................ 73 40 72 35 / 0 0 0 0 SANTA FE AIRPORT................ 75 42 74 39 / 0 0 0 0 ESPANOLA........................ 78 42 76 40 / 0 0 0 0 ALBUQUERQUE HEIGHTS............. 79 50 79 50 / 0 0 0 0 ALBUQUERQUE VALLEY.............. 81 48 81 48 / 0 0 0 0 ALBUQUERQUE FOOTHILLS........... 77 48 77 46 / 0 0 0 0 ALBUQUERQUE WEST MESA........... 80 48 80 48 / 0 0 0 0 SOCORRO......................... 86 48 85 50 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 73 41 71 36 / 0 0 0 0 MORIARTY/ESTANCIA............... 76 45 75 39 / 0 0 0 0 CARRIZOZO....................... 81 51 81 44 / 0 0 0 0 RUIDOSO......................... 71 45 72 40 / 0 0 0 0 RATON........................... 75 39 72 31 / 0 5 10 0 LAS VEGAS....................... 72 41 74 35 / 0 0 0 0 ROY............................. 78 47 76 37 / 0 0 0 0 CLAYTON......................... 80 48 73 38 / 0 5 5 0 SANTA ROSA...................... 84 51 83 45 / 0 0 0 0 TUCUMCARI....................... 85 54 80 45 / 0 0 0 0 FORT SUMNER..................... 84 53 85 48 / 0 0 0 0 CLOVIS.......................... 83 51 82 46 / 0 0 0 0 PORTALES........................ 84 52 84 47 / 0 0 0 0 ROSWELL......................... 89 55 92 54 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ101>109. FIRE WEATHER WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR THE FOLLOWING ZONES...NMZ102>104-107-108. && $$ GUYER/40
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1100 AM EDT FRI MAY 9 2008 .SYNOPSIS... LOW PRESSURE WAS MOVING OFF MID ATLANTIC COAST TODAY ALLOWING HIGH PRESSURE TO BUILD OVER THE REGION FROM THE NORTH. HIGH PRESSURE WILL LINGER OVER THE REGION SATURDAY BUT ANOTHER AREA OF LOW PRESSURE WILL MOVE EAST ACROSS THE LOCAL AREA ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LIGHT SHOWERS WILL CONTINUED TO MOVE OFF TO THE EAST. WHILE DRIER AIR SPREADS IN FROM THE NORTH. SATELLITE PICTURES INDICATED BREAKS IN THE CLOUD COVER OVER MOST OF REGION. CLOUDINESS WAS THINNING OUT OVER LAKE ERIE AND RIGHT ALONG THE LAKESHORE. SO PEAKS OF SUNSHINE CAN NOT BE RULED OUT THROUGH AFTERNOON. MORE CLOUDS WILL BE SPREADING FROM THE WEST. TAMDAR DATA FROM THIS MORNING SUPPORTS THE LOWER 60S FOR HIGHS THIS AFTERNOON. BUT WENT WITH A RANGE OF AROUND 55 NEAR THE LAKESHORE DUE TO NORTHEAST WIND OFF OF LAKE ERIE...WHICH IS AROUND 50 DEGREES. KEPT THE LOWER 60S OVER INLAND AREAS. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... GFS DEVELOPS A WEAK SURFACE LOW OVER SOUTHERN OHIO THIS EVENING. THIS APPEARS TO BE IN RESPONSE TO A QUICK MOVING WAVE THAT WILL PASS OVERHEAD THIS EVENING. NAM NOT SHOWING ANY SURFACE REFLECTION TO THIS WAVE. GIVEN FACT SURFACE RIDGING SHOULD BE OCCURRING WILL SHY AWAY FROM THE GFS SOLUTION WHICH GIVES QPF TO ENTIRE AREA THIS EVENING. INSTEAD WILL STICK WITH A FORECAST SIMILAR TO EARLIER PACKAGE WITH MINIMAL POPS FAR SOUTHERN AREAS FOR A FEW HOURS. DRIER AIR SHOULD ARRIVE OVERNIGHT AND WILL TRY FOR PARTLY CLOUDY ON SATURDAY. TEMPS WILL REMAIN A LITTLE BELOW NORMAL FOR SATURDAY WITH GUIDANCE REASONABLE. MODELS IN PRETTY GOOD AGREEMENT WITH THE NEXT FEATURE SET TO MOVE EAST OUT OF THE PLAINS ON SATURDAY NIGHT. SURFACE LOW WILL MOVE EAST ACROSS THE LOCAL AREA ON SUNDAY. PRECIP ASSOCIATED WITH THIS LOW WILL ARRIVE A LITTLE SLOWER THAN EARLIER THOUGHT. WILL NOT HAVE MUCH MENTION SATURDAY NIGHT BUT LIKELY WORDING NEEDED BOTH SUNDAY AND SUNDAY NIGHT. THE PRECIP SHOULD WIND DOWN FROM WEST TO EAST ON MONDAY. GFS SHOWS LI/S GETTING CLOSE TO ZERO ON SUNDAY. FOR NOW WILL LEAVE OUT MENTION OF THUNDER BUT LATER SHIFTS MAY HAVE TO ADD. TEMPS WILL REMAIN COOL BOTH SUNDAY AND MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... MODELS IN GOOD AGREEMENT MOVING LOW PRESSURE SYSTEM ACROSS THE STATE OF OHIO ON SUNDAY. THE LOW MOVES OFF THE EAST COAST MONDAY AND DUMBBELLS ALONG THE NEW ENGLAND COAST UNTIL HIGH PRESSURE FINALLY NUDGES OVER THE AREA ON TUESDAY. THE MODELS ARE NOW SHOWING A CUT-OFF LOW OVER THE CENTRAL PLAINS ON WEDNESDAY...EVENTUALLY MOVING OVER OHIO WEDNESDAY NIGHT. THIS IS A BIT FASTER THAN PREVIOUS RUNS BUT HAVE TO BELIEVE THAT THE MODELS ARE STILL ADVANCING THIS SYSTEM TOO FAR EAST TOO QUICKLY. WILL BRING LOW CHANCE POPS INTO THE WESTERN TIER COUNTIES WEDNESDAY AND EVENTUALLY BRING LOW CHANCE POPS OVER THE ENTIRE AREA WEDNESDAY NIGHT. SOME QUESTION AS TO HOW QUICKLY THIS SYSTEM WILL DEPART THE REGION ON THURSDAY. FOR NOW I WILL KEEP LOW CHANCE POPS AROUND ACROSS THE ENTIRE AREA DURING THE DAY ON THURSDAY AND DRY THINGS OUT IN THE WEST THURSDAY NIGHT. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE SYTEM ON INTO WESTERN VIRGINIA AND SHOULD PUSH OFF THE MID ATLANTIC COAST EARLY THIS AFTERNOON. CONDTIONS WILL IMPROVE TO VFR FROM THE WEST BY EARLY AFTERNOON AS THE LOW MOVES EAST. OUTLOOK...EXPECT VFR CONDTIONS SATURDAY AS A LARGE AREA OF HIGH PRESSURE MOVES ACROSS THE GREAT LAKES. STONG LOW PRESSURE SYSTEM WILL MOVE ACROOS THE STATE OF OHIO ON SUNDAY. EXPECT SHOWERS WITH THE CHANCE OF TSRA. DEPENDING ON HOW FAR NORTH THE LOW REACHES COULD SEE SOME IFR/LIFR CONDTIONS. EXPECT THE RAIN TO LINGER INTO MONDAY. LUCKILY HIGH PRESSURE MOVES ACROSS THE GREAT LAKES ON TUESDAY. && .MARINE... SMALL CRAFT ADVISORY CRITERIA TODAY DUE TO A LOW PRESSURE SYSTEM MOVING ACROSS THE OHIO VALLEY. LOW WILL MOVE OFF THE EAST COAST LATE THIS AFTERNOON ALLOWING THE GRADIENT TO WEAKEN AND TO DROP BELOW SCA. HIGH PRESSURE WILL MOVE ACROSS THE LAKES SATURDAY PROVIDING LIGHT WINDS. MODELS IN GOOD AGREEMENT MOVING STRONG LOW ACROSS THE STATE OF OHIO ON SUNDAY. WILL REQUIRE ANOTHER SCA THROUGH MONDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR LEZ142>149. && $$ SYNOPSIS...KUBINA NEAR TERM...THOMPSON SHORT TERM...KUBINA LONG TERM...DJB AVIATION...DJB MARINE...DJB
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
300 AM PDT SUN MAY 11 2008 .SHORT TERM (TODAY THROUGH TUESDAY)...LATEST SATELLITE SHOWS STRATUS AND FOG FILLING IN OVER THE COASTAL WATERS AND ACROSS THE COASTAL PLAIN. LATEST AMDAR SOUNDINGS INDICATE MARINE INVERSION DEPTH AROUND 1200 FT. SO...WITH GOOD ONSHORE PUSH...WILL EXPECT AT LEAST AREAS OF STRATUS/FOG INTO THE COASTAL VALLEYS THIS MORNING. GIVEN THE CURRENT DEPTH OF THE MARINE LAYER...WOULD EXPECT PRETTY GOOD CLEARING THIS AFTERNOON. HOWEVER...CONFIDENCE IN GOOD CLEARING IS ONLY MODERATE AT BEST. SO...WILL INDICATE PARTLY CLOUDY SKIES IN THE AFTERNOON FOR COASTAL/VALLEY AREAS SOUTH OF PT CONCEPTION. OTHER THAN THE MARINE LAYER...SKIES WILL BE SUNNY ACROSS THE AREA TODAY. FOR TONIGHT/MONDAY...WILL EXPECT VERY SIMILAR MARINE LAYER CONDITIONS ALTHOUGH WILL NOT ANTICIPATE ANY STRATUS INTO THE SALINAS RIVER VALLEY. ONCE AGAIN...WILL GO WITH PARTLY CLOUDY SKIES MONDAY AFTERNOON FOR COASTAL/VALLEY AREAS SOUTH OF PT CONCEPTION GIVEN FORECASTED STRONG ONSHORE GRADIENTS. BY MONDAY NIGHT/TUESDAY...MARINE LAYER SHOULD BE LESS IN DEPTH AND AREAL COVERAGE AS SOME NORTHERLY FLOW IS INDICATED BY 00Z MODELS. SO...BY TUESDAY AFTERNOON...SKIES SHOULD BE SUNNY FOR ALL AREAS. AS FOR TEMPS...WILL EXPECT CONTINUED COOL CONDITIONS TODAY AND MONDAY WITH MARINE LAYER PRESENCE AND ONSHORE FLOW. BY TUESDAY... TEMPS SHOULD START TO RECOVER AS MARINE INFLUENCE DECREASES AND ONSHORE FLOW DIMINISHES. WITH THE GOOD ONSHORE GRADIENTS TODAY AND MONDAY...SOME GUSTY AFTERNOON/EVENING WINDS WILL CONTINUE ACROSS THE MOUNTAINS AND ANTELOPE VALLEY. WINDS COULD APPROACH ADVISORY LEVELS ACROSS THE ANTELOPE VALLEY. HOWEVER...CONFIDENCE IN ADVISORY LEVEL WINDS IS LOW...SO WILL KEEP WINDS JUST BELOW ADVISORY LEVELS. .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...EXTENDED MODELS CONTINUE TO ADVERTISE A VERY WARM AND DRY PATTERN FOR THE AREA THROUGH THE PERIOD. BOTH THE GFS/ECMWF HANDLES THE UPPER HIGH OVER THE WEST COAST VERY WELL. THE DIFFERENCES BETWEEN THE GFS AND ECMWF CONTINUE TO BE WITH THE TROUGH OVER THE CENTRAL STATES. THE GFS KEEPS THE TROUGH OVER NEW MEXICO/WESTERN TEXAS WHILE THE ECMWF IS MORE PROGRESSIVE WITH THE TROUGH. ADMITTEDLY THE LOCATION OF THE UPPER TROUGH WILL HAVE SOME INFLUENCE ON THE OVERALL PATTERN...BUT EITHER WAY...IT STILL WILL BE A VERY WARM FEW DAYS LATER IN THE WEEK DUE TO VARYING DEGREES OF OFFSHORE FLOW. LOCAL TEMP STUDY GUIDANCE DEFINITELY SUPPORTS POTENTIAL FOR SIGNIFICANTLY WARM TEMPS DURING THE PERIOD...ESPECIALLY WEDNESDAY AND THURSDAY. HAVE BUMPED UP PREVIOUS SHIFT`S TEMPS FOR WEDNESDAY AND THURSDAY. HOWEVER...IF MODEL TRENDS CONTINUE IN THE SAME VEIN COASTAL/VALLEY TEMPS WILL BE SEVERAL DEGREES THAN FORECASTED THIS MORNING. SO...SITUATION WILL HAVE TO BE MONITORED CLOSELY. BY FRIDAY/SATURDAY...THE OFFSHORE GRADIENTS START TO WEAKEN AS THE UPPER HIGH WEAKENS. SO...WILL EXPECT SOME COOLER TEMPS NEXT WEEKEND...BUT STILL WARMER THAN NORMAL CONDITIONS THROUGH THE PERIOD. && .AVIATION...11/1130Z. WILL BE UPDATED SHORTLY. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...THOMPSON AVIATION...BRUNO WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
452 AM EDT SUN MAY 11 2008 .SYNOPSIS... WEAK HIGH PRESSURE OVER THE AREA EARLY THIS MORNING WILL RECEDE EAST. COMPLEX LOW PRESSURE WILL APPROACH FROM THE WEST TODAY, CONSOLIDATE OFF THE NORTHERN MID-ATLANTIC COAST EARLY ON MONDAY, AND THEN MOVE SLOWLY OUT TO SEA. HIGH PRESSURE IS FORECAST TO BUILD INTO OUR REGION FROM THE WEST FOR THE MID-WEEK PERIOD. A COLD FRONT IS EXPECTED TO FOLLOW FOR FRIDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AFTER A SUNNY START TO THE DAY, CLOUDS SHOULD BEGIN TO INVADE FROM THE WEST AND SOUTHWEST. THE GFS AND THE ECMWF ARE A BIT QUICKER TO BRING PRECIPITATION INTO THE AREA THAN THE NAM. INITIALLY, WE`RE DEALING WITH ISENT LIFT PRECIP AT AROUND I300. THE SYSTEM RESPONSIBLE, AS NOTED IN PREVIOUS DISCUSSIONS, IS A VIGOROUS MID LEVEL TROF THAT IS IN THE PROCESS OF CUTTING OFF AS A STRONG UPPER LEVEL JET DROPS INTO ITS BASE. THE MID LEVEL LOW WILL BE MOVING INTO THE UPPER OHIO RIVER VALLEY BY THE END OF THE DAY, AND IT WILL BEGIN TO TRANSFER ENERGY AT THE SURFACE FROM A PRIMARY LOW NEAR THE PARENT MID LEVEL SYSTEM TO A SECONDARY LOW OVER VIRGINIA. WE HAVE MAINTAINED CONTINUITY ON TEMPERATURES. WINDS ARE EXPECTED TO BEGIN TO PICK UP OUT OF THE EAST OR SOUTHEAST DURING THE AFTERNOON, WHICH MAKES CONTINUITY SEEM LIKE A GOOD IDEA, AND THE FIRST CHANCE OF PRECIP SHOULD BE LATER IN THE AFTERNOON OVER THE SOUTHWESTERN PART OF THE FORECAST AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE SYSTEM WILL GENERATE A FAIRLY STRONG WIND FIELD, CARRY GOOD MID AND UPPER LEVEL DYNAMICS, GENERATE GOOD LOWER LEVEL FRONTOGENESIS, AND PERHAPS CARRY WITH IT SOME ELEVATED INSTABILITY. THE STRONG AND FAIRLY DEEP WINDS ABOVE THE SURFACE AND OFF THE OCEAN SHOULD CARRY AS MUCH ATLANTIC MOISTURE AS IS POSSIBLE, ALTHOUGH, AGAIN, WE HAVE A HARD TIME SEEING VERY HIGH H8 DEWPOINTS IN OUR REGION IN THE MORE MOIST GFS. THE GFS CARRIES 5 DEG C VALUES AS FAR NORTH AS ABOUT PHL AND CARRIES 8 DEG C VALUES INTO OUR FAR SOUTHERN ZONES. FURTHER TO THE NORTH, MORE REMOVED FROM THE SYSTEM, H8 DEW POINTS ARE EVEN LOWER. WITHOUT THE POSSIBILITY OF SOME CONVECTION, WHICH IS DEPICTED /AS ELEVATED CONVECTION/ A BIT MORE EMPHATICALLY IN THE GFS THAN THE NAM, WE WOULD BE TEMPTED TO UNDERCUT MODEL QPF A BIT AS THE MODELS HAVE A HIGH BIAS IN NON- CONVECTIVE EVENTS. HOWEVER, IT IS THE FEAR OF ELEVATED CONVECTION THAT KEPT US FROM DOING THAT. THAT MAKES FOR SOME RESPECTABLE PRECIPITATION AMOUNTS OVER ABOUT THE SOUTHERN HALF TO TWO-THIRDS OF THE AREA. WE INCLUDE A HYDRO SECTION BELOW. THE WIND FIELDS SHOW A CONSIDERABLE AMOUNT OF SHEAR, AND WE HOPE WE ARE CORRECT THAT ANY CONVECTION WOULD BE ALOFT. THAT IS WHAT THE SURFACE-BASED STABILITY PROGS SHOW, AND THAT IS HOW SPC AND WE ARE PLAYING IT. WINDS ALSO WILL BEGIN STRENGTHEN SUFFICIENTLY, FIRST OUT OF THE EAST TO SOUTHEAST TONIGHT, THEN OUT OF THE NORTHEAST ON MONDAY, TO CAUSE SOME TIDAL CONCERNS AS NOTED BELOW. IT IS POSSIBLE, AFTER THE TRANSFERRENCE OF ENERGY AT THE SURFACE IS COMPLETE, THAT THE SYSTEM WOULD WIND UP ENOUGH ON MONDAY TO EVENTUALLY CAUSE US TO ISSUE A WIND ADVISORY, AT LEAST ALONG THE COAST, BUT BUFKIT FROM THE GFS LOOKS MARGINAL AND WE HAVE PASSED ON THAT FOR THE TIME BEING. THE CONSOLIDATED SYSTEM EXITS SLOWLY ON MONDAY, PERHAPS A BIT TOO SLOWLY AS DEPICTED BY THE NAM, AND THE BULK OF THE SIGNIFICANT PRECIPITATION SHOULD BE OVER WITH BEFORE EVENING. STABILITY PROGS, AT THE SURFACE AND ALOFT, INDICATE THAT THE THREAT OF CONVECTION MAY BE OVER WITH EARLY ON MONDAY, AND WE`RE NOT CARRYING ANY MENTION OF THUNDER AFTER TONIGHT FOR NOW. GRADUAL IMPROVEMENT IS FORECAST OVER LAND ON MONDAY NIGHT AND TUESDAY. AGAIN, CONTINUITY ON TEMPERATURES WAS MOSTLY ACCEPTED. WE DID ACTUALLY LOWER THE MONDAY MAXES OVER ALL BUT THE FAR SOUTHERN ZONES. SOUNDINGS FROM THIS RUN DON`T SHOW ANY PRECIP TYPE CONCERNS, BUT WE`LL CONTINUE TO WATCH THAT. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AT MID WEEK, WE ARE EXPECTING TO SEE THE UPPER LOW TAKING ITS TIME MOVING OUT TO SEA. MEANWHILE, AN UPPER RIDGE AXIS IS FORECAST TO EXTEND FROM THE GULF COAST UP INTO THE GREAT LAKES REGION ON TUESDAY NIGHT. AS THE LOW DRIFTS EASTWARD, SO WILL THE RIDGE. THE RIDGE AXIS IS EXPECTED TO PASS OVER OUR REGION FROM WEDNESDAY NIGHT INTO THURSDAY. AN UPPER LEVEL TROUGH IS FORECAST TO DIG INTO THE EASTERN STATES ON FRIDAY AND SATURDAY. A SURFACE COLD FRONT, ASSOCIATED WITH THE UPPER TROUGH, SHOULD PASS THROUGH OUR REGION ON FRIDAY NIGHT. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE OVER THE AREA WILL MOVE OFFSHORE THIS MORNING. LIGHT WEST WINDS...OR CALM WINDS...WERE ALLOWING FOR SOME RADIATIONAL COOLING EARLY THIS MORNING, AND FOG HAS WAFTED IN AND OUT AT KRDG. A COUPLE OF OTHER PLACES MAY HAVE SOME BRIEF IFR VISIBILITIES IN FOG, OTHERWISE CIRRUS WILL BE INCREASING FROM THE WEST-SOUTHWEST AS THE MORNING WEARS ON. LOW PRESSURE WILL APPROACH FROM THE OHIO VALLEY TODAY AND WEAKEN AS SECONDARY DEVELOPMENT TAKES PLACES ALONG THE VIRGINIA CAPES LATE TODAY AND EARLY TONIGHT. WITH THE DEVELOPING ONSHORE FLOW AND INFLUX OF MID AND THEN LOW LEVEL MOISTURE, CEILINGS WILL GRADUALLY LOWER TO MARGINAL VFR LATER THIS AFTERNOON, WITH RAIN DEVELOPING AS THE COLUMN MOISTENS LATE TODAY OR MORE LIKELY THIS EVENING, PROBABLY FROM WEST-SOUTHWEST TO EAST-NORTHEAST. LIGHT WINDS (WITH A WESTERLY COMPONENT) EARLY THIS MORNING WILL BACK AROUND TO EAST OR EAST-SOUTHEAST AND STRENGTHEN AS THE STORM SYSTEM NEARS. AN INCREASING PRESSURE GRADIENT MAY BECOME TIGHT ENOUGH TO ALLOW FOR GUSTS TO OCCUR FROM ABOUT MID AFTERNOON ON, ESPECIALLY FROM KPHL SOUTH AND EAST. A WIND SHEAR REMARK WAS ADDED LATE IN THE TAF VALID PERIOD AS LOW LEVEL WINDS WILL BE SCREAMING OUT OF THE EAST. SURFACE WINDS WILL BE GUSTY, BUT IT WAS FELT THAT A POINTER TO 45 TO 50 KNOT WINDS JUST OFF THE SURFACE WOULD BE BENEFICIAL. OUTLOOK... CONDITIONS WILL BE MARGINAL VFR IN STRATUS, WITH RAIN HEAVY AT TIMES AND FOG TONIGHT INTO MONDAY AS THE STORM IMPACTS THE REGION. WIDESPREAD RAIN AND GUSTY WINDS WILL NEGATIVELY IMPACT AIRCRAFT OPERATIONS SIGNIFICANTLY MONDAY. GRADUAL IMPROVEMENT IS EXPECTED LATE MONDAY NIGHT AND ESPECIALLY TUESDAY, BUT LINGERING NEGATIVE IMPACTS ARE LIKELY EVEN TUESDAY. HIGH PRESSURE IS FORECAST TO RETURN WEDNESDAY, HOWEVER A COLD FRONT MAY APPROACH FROM THE WEST THURSDAY WITH A CHANCE OF SHOWERS. && .MARINE... STRENGTHENING LOW PRESSURE APPROACHING FROM THE OHIO VALLEY TODAY WILL SHIFT ITS ENERGY TO THE VIRGINIA CAPES EARLY TONIGHT, WITH A GOOD OLD FASHIONED (MAY?) NOR`EASTER ON OUR HANDS. IT LOOKS LIKE A PRETTY GOOD BLOW WITH GOOD WAVE ACTION (OVER 10 FEET MONDAY AND MONDAY NIGHT), SO ANY SUNDAY PARTY BOATERS SHOULD PLAN ON RETURNING THIS AFTERNOON OR EARLY TONIGHT. MODEL OUTPUT LENT CONFIDENCE TO THE FORECAST, AS MODELS WERE CONSISTENT FROM PREVIOUS RUNS AND THERE WAS LITTLE SPREAD IN MODEL SOLUTIONS. FIRST, UPPER DELAWARE BAY: WINDS MAY GUSTS AT TIMES TO 35 KNOTS TONIGHT INTO TUESDAY, BUT ON THE WHOLE IT WAS THOUGHT THAT THIS WOULD BE A MINORITY OF THE TIME, SO THE SMALL CRAFT ADVISORY WAS LEFT INTACT AND EXTENDED THROUGH 10Z TUESDAY. THE INHERITED GALE WARNING ON THE SOUTHERN OCEAN WATERS WAS ALSO CONTINUED, AND LIKEWISE EXTENDED THROUGH 10Z TUESDAY (OUR 4TH PERIOD). HOWEVER, WE DID BACK UP THE STARTING TIME A COUPLE OF HOURS FROM 22Z TODAY TO 00Z MONDAY. THE NORTHERN OCEAN WATERS WERE ALSO BROUGHT INTO A GALE WARNING AT THIS TIME, AS THE TIGHTEST GRADIENT APPEARS TO SHIFT TO THE NORTH TONIGHT AND LINGER MONDAY. SO, THE STARTING TIME WAS A FEW HOURS AFTER THE SOUTHERN WATERS, ALLOWING FOR SOME TIME FOR THE GRADIENT TO BECOME COMPRESSED FURTHER NORTH. THIS TOO WILL EXTEND THROUGH 10Z TUESDAY. WAVES IN THE 8 TO 12 FOOT RANGE ON THE OCEAN WERE PRETTY MUCH CONTINUED, ALTHOUGH WAVEWATCH HAD A LITTLE HIGHER SOLUTION FOR A FEW TIME PERIODS MONDAY. FOR THE OUTLOOK, HIGH PRESSURE SHOULD FOLLOW FOR THE MIDDLE OF THE COMING WEEK, HOWEVER A COLD FRONT IS LIKELY TO APPROACH THURSDAY. && .HYDROLOGY... WE ARE EXPECTING AROUND AN INCH OR SO OF RAINFALL JUST NORTH OF THE ELEVATED CONVECTION AREA, WHICH IS TO SAY FROM NORTH OF READING TO NORTH OF TRENTON AND JUST NORTH OF INTERSTATE 195. AS WE MOVE FURTHER SOUTH, THE THREAT OF ELEVATED CONVECTION AND THE AMOUNT OF AVAILABLE MOISTURE INCREASES. WE COULD EASILY SEE AREAS WITH IN EXCESS OF TWO INCHES OVER MUCH OF THE DELMARVA AND FAR SOUTHERN NEW JERSEY, BUT BASED ON HEADWATER GUIDANCE /FFH/ AND FLASH FLOOD /FFG/, THESE AMOUNTS WOULDN`T CAUSE ANYTHING OTHER THAN POOR-DRAINAGE OR ROADWAY FLOODING. THE AREA OF CONCERN IS FAR SOUTHEASTERN PENNSYLVANIA, NORTHERN DELAWARE AND NORTHEAST MARYLAND, WHERE FFH AND/OR FFG VALUES WOULD BE WITHIN REACH ONCE WE APPROACH TWO INCHES. WE THEREFORE HAVE ISSUED A FLOOD WATCH. && .TIDES/COASTAL FLOODING... THE DECISION WAS MADE TO ISSUE A COASTAL FLOOD ADVISORY FOR WIDESPREAD MINOR TIDAL FLOODING FOR THE HIGH TIDE CYCLE LATE TONIGHT ON THE OCEAN FRONT (AND ADJACENT BACK BAYS), AND ALSO TO ISSUE A COASTAL FLOOD WATCH FOR THE SAME AREAS FOR MONDAY AND MONDAY NIGHT AS SURGE GUIDANCE PAINTS SIGNIFICANT TIDE DEPARTURES. ITS POSSIBLE THAT LINGERING EFFECTS WILL OCCUR TUESDAY AS WELL, BUT SINCE THAT`S WAY OUT ON THE TIME HORIZON, THAT CAN BE LEFT FOR A LATER DAY. AS THE DEVELOPING LOW PRESSURE AREA APPROACHES THIS AFTERNOON AND AFFECTS THE AREA TONIGHT THROUGH TUESDAY, BOTH THE NGM AND AVIATION STORM SURGE GUIDANCE SHOW PRONOUNCED POSITIVE ANOMALIES, ESPECIALLY MONDAY AND MONDAY NIGHT. STARTING OFF TONIGHT, ONLY MINOR TIDAL FLOODING IS FORESEEN FOR TONIGHT, BUT SINCE CONFIDENCE IS HIGH THAT IT WILL BE WIDESPREAD (AS MODELS HAVE BEEN CONSISTENT RUN-TO-RUN AND MODEL-TO-MODEL), IT WAS THOUGHT TO ISSUE THE ADVISORY NOW SO AS TO PROVIDE GOOD LEAD TIME. AN ADVISORY IS ALSO LIKELY TO BE NEEDED FOR DELAWARE BAY AND THE TIDAL PORTIONS OF THE DELAWARE RIVER MONDAY (MORNING), BUT THAT CAN BE ADDRESSED BY LATER SHIFTS. THE AFTERNOON HIGH TIDE CYCLE ON THE OCEAN FRONT IS THE LOWER OF THE TWO DAILY HIGH TIDES, WHICH MAY BE SOMEWHAT OF A SAVING FACTOR MONDAY; HOWEVER, SOME FORECASTS FOR MONDAY NIGHT ARE A BIT LOWER THAN THEY WERE FOR MONDAY AFTERNOON, ALTHOUGH ITS NOT CLEAR WHY THIS WOULD BE SO AS THE WINDS SHOULD STILL BE FROM A FAVORABLE NORTHEAST DIRECTION AND STILL QUITE STRONG. LATER MODEL RUNS MAY SHOW EQUAL ANOMALIES, SO THE DECISION WAS MADE THAT MONDAY NIGHT MAY HAVE ONLY SLIGHTLY LESS OR EVEN THE SAME EFFECTS AS MONDAY, AND A WATCH WOULD BE WARRANTED FOR BOTH TIME FRAMES SINCE THERE COULD BE AREAS OF MODERATE TIDAL FLOODING. AS INFORMATION CRYSTALLIZES LATER TODAY AND TONIGHT, PERHAPS THE WATCH COULD BE TRANSFORMED INTO AN ADVISORY IF WATCH/WARNING CRITERIA NO LONGER APPEAR TO BE MET. OR, HEY, MAYBE A WARNING WILL BE NEEDED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR PAZ067-070-071. NJ...COASTAL FLOOD WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR NJZ012>014-020-022>027. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT MONDAY FOR NJZ012>014-020-022>027. DE...COASTAL FLOOD WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR DEZ003-004. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT MONDAY FOR DEZ003-004. FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR DEZ001. MD...FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR MDZ008. MARINE...GALE WARNING FROM 8 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ431-452>455. GALE WARNING FROM 11 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ450-451. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ430. && $$ SYNOPSIS...DELISI NEAR TERM...DELISI SHORT TERM...DELISI LONG TERM...IOVINO AVIATION... MARINE... HYDROLOGY...DELISI TIDES/COASTAL FLOODING...
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
915 AM PDT SUN MAY 11 2008 .SHORT TERM (TODAY THROUGH TUESDAY)... STRATUS ALREADY STARTING TO BREAK UP ALONG THE CENTRAL COAST THIS MORNING...BUT A RATHER SOLID LAYER PERSISTS JUST OFF THEIR IMMEDIATE COAST...AS WELL AS BLANKETING THE ENTIRE COASTAL AND VALLEY AREAS SOUTH OF PT CONCEPTION. LATEST AIRCRAFT SOUNDINGS SHOW THE MARINE LAYER NEAR 2800 FT AT LAX...AND WITH RATHER LOW CEILINGS FOR THIS DEEP OF A MARINE LAYER...THE STRATUS LAYER LOOKS PRETTY THICK. THIS THICK LAYER...WHEN COUPLED WITH A STRENGTHENING ONSHORE GRAD...HAS TO SUGGEST A RATHER TOUGH CLEARING DAY. NOT ONLY THAT...BUT THE STRENGTHENING GRADS WILL HELP THE STRATUS PUSH EVEN DEEPER INLAND INTO THE AFTERNOON...AND EXPECTING THE COASTAL SLOPES AND SANTA CLARITA VALLEY TO BE COVERED BY NOON. A SIMILAR IF NOT MORE BLANKETED DAY IS EXPECTED FOR MON. UPDATED THE FORECAST TO ADD SOME PESSIMISM IN THIS REGARD. TEMPS LOOK GOOD OVERALL...WITH A FEW DEGREES OF COOLING EXPECTED TODAY AND AGAIN ON MON ACROSS THE BOARD. THANKS CAN BE GIVEN TO THE INCREASED CLOUD COVERAGE AND LOWER THICKS FROM A LOW CURRENTLY OVER WASHINGTON THAT CONTINUES TO SAG SOUTHWARD. A MODERATE ONSHORE WIND DAY IS EXPECTED. ALTHOUGH NO WIND ADVISORIES ARE ANTICIPATED AT THIS TIME...IT SHOULD GET BREEZY IN THE ANTELOPE VALLEY. MON LOOKS A BIT WINDIER...AND ADVISORIES ARE NOT OUT OF THE QUESTION IN THE ANTELOPE VALLEY...AND TO A LESSER EXTENT THE CENTRAL COAST AND SANTA CLARITA VALLEY. ...FROM PREVIOUS DISCUSSION... BY MONDAY NIGHT/TUESDAY...MARINE LAYER SHOULD BE LESS IN DEPTH AND AREAL COVERAGE AS SOME NORTHERLY FLOW IS INDICATED BY 00Z MODELS. SO...BY TUESDAY AFTERNOON...SKIES SHOULD BE SUNNY FOR ALL AREAS. .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...EXTENDED MODELS CONTINUE TO ADVERTISE A VERY WARM AND DRY PATTERN FOR THE AREA THROUGH THE PERIOD. BOTH THE GFS/ECMWF HANDLES THE UPPER HIGH OVER THE WEST COAST VERY WELL. THE DIFFERENCES BETWEEN THE GFS AND ECMWF CONTINUE TO BE WITH THE TROUGH OVER THE CENTRAL STATES. THE GFS KEEPS THE TROUGH OVER NEW MEXICO/WESTERN TEXAS WHILE THE ECMWF IS MORE PROGRESSIVE WITH THE TROUGH. ADMITTEDLY THE LOCATION OF THE UPPER TROUGH WILL HAVE SOME INFLUENCE ON THE OVERALL PATTERN...BUT EITHER WAY...IT STILL WILL BE A VERY WARM FEW DAYS LATER IN THE WEEK DUE TO VARYING DEGREES OF OFFSHORE FLOW. LOCAL TEMP STUDY GUIDANCE DEFINITELY SUPPORTS POTENTIAL FOR SIGNIFICANTLY WARM TEMPS DURING THE PERIOD...ESPECIALLY WEDNESDAY AND THURSDAY. HAVE BUMPED UP PREVIOUS SHIFT`S TEMPS FOR WEDNESDAY AND THURSDAY. HOWEVER...IF MODEL TRENDS CONTINUE IN THE SAME VEIN COASTAL/VALLEY TEMPS WILL BE SEVERAL DEGREES THAN FORECASTED THIS MORNING. SO...SITUATION WILL HAVE TO BE MONITORED CLOSELY. BY FRIDAY/SATURDAY...THE OFFSHORE GRADIENTS START TO WEAKEN AS THE UPPER HIGH WEAKENS. SO...WILL EXPECT SOME COOLER TEMPS NEXT WEEKEND...BUT STILL WARMER THAN NORMAL CONDITIONS THROUGH THE PERIOD. && .AVIATION...11/1230Z. STRATUS WDSPRD IN CSTL AND VLYS THIS MORNING. WITH INCREASING ONSHORE GRADS...CIGS WILL LIKELY BE SLOW TO CLEAR IN THE VALLEYS...AND PROBABLY WILL NOT CLEAR NEAR THE COAST. KLAX...MVFR CIGS THIS MORNING. DO NOT EXPECT CIGS TO SCATTER OUT THIS AFTERNOON. CONFIDENCE IS LOW TO MODERATE. TYPICAL SEABREEZE NEAR 10 KT THIS AFTERNOON. KBUR...EXPECT IFR CIGS TO BECOME MVFR BY MID OR LATE MORNING. CIGS SHOULD SCATTER OUT AROUND 21Z OR 22Z. CONFIDENCE ON CLEARING IS LOW TO MODERATE. NO WIND ISSUES WITH TYPICAL S TO SE WINDS AROUND 10 KT THIS AFTERNOON. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...KITTELL/THOMPSON AVIATION...BRUNO WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
900 AM PDT SUN MAY 11 2008 .SYNOPSIS... A TROUGH OF LOW PRESSURE MOVING THROUGH THE PACIFIC NORTHWEST TODAY AND GREAT BASIN MONDAY WILL BRING STRONGER ONSHORE FLOW...A DEEPER MARINE LAYER...AND COOLER WEATHER THROUGH MONDAY. THIS TROUGH WILL ALSO BRING STRONGER ONSHORE WINDS FOR THE MOUNTAINS AND DESERTS MONDAY AFTERNOON AND EVENING. FOR TUESDAY THROUGH THE END OF THE WEEK...STRONG HIGH PRESSURE WILL BUILD ALONG THE WEST COAST WITH DRIER AND MUCH WARMER WEATHER FOR WEDNESDAY INTO THE WEEKEND. DAYTIME TEMPERATURES WILL RISE TO WELL ABOVE SEASONAL AVERAGES. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... LOW CLOUDS WILL CLEAR TO THE COAST THIS MORNING AND THE AFTERNOON WILL BE SUNNY IN MOST SPOTS. THE APPROACHING UPPER LEVEL LOW FROM THE NORTHWEST WILL DEEPEN THE MARINE LAYER TONIGHT AND MON ALLOWING THE CLOUDS TO BE MORE PERSISTENT IN THE COASTAL BASIN. THERE WILL BE PATCHY DRIZZLE UNDER THE CLOUDS AS WELL AS FOG ON THE COASTAL MTN SLOPES. THIS TROUGH WILL ALSO CRANK UP WINDS IN THE MTNS AND DESERTS MON AFTERNOON AND EVE. AS THE LOW MOVES EASTWARD TUE THE WEATHER WILL TREND FROM DEEP MARINE LAYER TO CLEARER AND WARMER. A STRONG UPPER HIGH WILL NOSE IN FROM THE PACIFIC AND WILL STRENGTHEN AND AMPLIFY ALONG THE WEST COAST WED INTO THE WEEKEND. THIS WILL SQUASH THE MARINE LAYER DOWN TO ALMOST NOTHING...AND IF ANY COASTAL CLOUDS ARE LEFT OVER...A TOUCH OF OFFSHORE FLOW SHOULD FINISH THEM BY THU OR FRI. MUCH HIGHER DAYTIME TEMPS WILL BE THE BIG STORY. THE HIGH BEGINS TO BREAK DOWN OVER THE WEEKEND AND TEMPS WILL BEGIN TO TREND BACK TOWARD NORMAL. && .AVIATION... 111430Z...THE 12Z NKX SOUNDING AS WELL AS MDCRS SOUNDINGS NEAR KSAN AND KLAX SHOW THE MARINE LAYER DEPTH TO BE NEAR 2800 FEET THIS MORNING. THE MARINE LAYER SHOULD DEEPEN TO 3500 TO 4000 FEET TONIGHT. STRATUS WITH BASES BETWEEN 1500 AND 2000 FEET MSL EXTENDS INLAND OVER THE INLAND VALLEY AREAS. EXPECT THE STRATUS OVER THE INLAND AREAS TO BEGIN TO BURN OFF BETWEEN 15Z AND 16Z AND THE COASTAL AREAS BETWEEN 17Z AND 19Z. STRATUS SHOULD RETURN TO THE COASTAL AREAS BY SUNSET AND PUSH INLAND DURING THE EVENING REACHING THE FAR INLAND VALLEY AREAS BY MIDNIGHT. SOME BREAKUP OF THE STRATUS IS EXPECTED ON MONDAY OVER THE INLAND AREAS BUT THE COASTAL AREAS SHOULD NOT HAVE MUCH BREAK UP OF THE STRATUS ON MONDAY. ABOVE THE MARINE LAYER INCLUDING THE MOUNTAINS AND DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VISIBILITIES WILL CONTINUE THROUGH MONDAY. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...MM AVIATION/MARINE...HORTON
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
530 AM PDT SUN MAY 11 2008 UPDATED AVIATION SECTION .SHORT TERM (TODAY THROUGH TUESDAY)...LATEST SATELLITE SHOWS STRATUS AND FOG FILLING IN OVER THE COASTAL WATERS AND ACROSS THE COASTAL PLAIN. LATEST AMDAR SOUNDINGS INDICATE MARINE INVERSION DEPTH AROUND 1200 FT. SO...WITH GOOD ONSHORE PUSH...WILL EXPECT AT LEAST AREAS OF STRATUS/FOG INTO THE COASTAL VALLEYS THIS MORNING. GIVEN THE CURRENT DEPTH OF THE MARINE LAYER...WOULD EXPECT PRETTY GOOD CLEARING THIS AFTERNOON. HOWEVER...CONFIDENCE IN GOOD CLEARING IS ONLY MODERATE AT BEST. SO...WILL INDICATE PARTLY CLOUDY SKIES IN THE AFTERNOON FOR COASTAL/VALLEY AREAS SOUTH OF PT CONCEPTION. OTHER THAN THE MARINE LAYER...SKIES WILL BE SUNNY ACROSS THE AREA TODAY. FOR TONIGHT/MONDAY...WILL EXPECT VERY SIMILAR MARINE LAYER CONDITIONS ALTHOUGH WILL NOT ANTICIPATE ANY STRATUS INTO THE SALINAS RIVER VALLEY. ONCE AGAIN...WILL GO WITH PARTLY CLOUDY SKIES MONDAY AFTERNOON FOR COASTAL/VALLEY AREAS SOUTH OF PT CONCEPTION GIVEN FORECASTED STRONG ONSHORE GRADIENTS. BY MONDAY NIGHT/TUESDAY...MARINE LAYER SHOULD BE LESS IN DEPTH AND AREAL COVERAGE AS SOME NORTHERLY FLOW IS INDICATED BY 00Z MODELS. SO...BY TUESDAY AFTERNOON...SKIES SHOULD BE SUNNY FOR ALL AREAS. AS FOR TEMPS...WILL EXPECT CONTINUED COOL CONDITIONS TODAY AND MONDAY WITH MARINE LAYER PRESENCE AND ONSHORE FLOW. BY TUESDAY... TEMPS SHOULD START TO RECOVER AS MARINE INFLUENCE DECREASES AND ONSHORE FLOW DIMINISHES. WITH THE GOOD ONSHORE GRADIENTS TODAY AND MONDAY...SOME GUSTY AFTERNOON/EVENING WINDS WILL CONTINUE ACROSS THE MOUNTAINS AND ANTELOPE VALLEY. WINDS COULD APPROACH ADVISORY LEVELS ACROSS THE ANTELOPE VALLEY. HOWEVER...CONFIDENCE IN ADVISORY LEVEL WINDS IS LOW...SO WILL KEEP WINDS JUST BELOW ADVISORY LEVELS. .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...EXTENDED MODELS CONTINUE TO ADVERTISE A VERY WARM AND DRY PATTERN FOR THE AREA THROUGH THE PERIOD. BOTH THE GFS/ECMWF HANDLES THE UPPER HIGH OVER THE WEST COAST VERY WELL. THE DIFFERENCES BETWEEN THE GFS AND ECMWF CONTINUE TO BE WITH THE TROUGH OVER THE CENTRAL STATES. THE GFS KEEPS THE TROUGH OVER NEW MEXICO/WESTERN TEXAS WHILE THE ECMWF IS MORE PROGRESSIVE WITH THE TROUGH. ADMITTEDLY THE LOCATION OF THE UPPER TROUGH WILL HAVE SOME INFLUENCE ON THE OVERALL PATTERN...BUT EITHER WAY...IT STILL WILL BE A VERY WARM FEW DAYS LATER IN THE WEEK DUE TO VARYING DEGREES OF OFFSHORE FLOW. LOCAL TEMP STUDY GUIDANCE DEFINITELY SUPPORTS POTENTIAL FOR SIGNIFICANTLY WARM TEMPS DURING THE PERIOD...ESPECIALLY WEDNESDAY AND THURSDAY. HAVE BUMPED UP PREVIOUS SHIFT`S TEMPS FOR WEDNESDAY AND THURSDAY. HOWEVER...IF MODEL TRENDS CONTINUE IN THE SAME VEIN COASTAL/VALLEY TEMPS WILL BE SEVERAL DEGREES THAN FORECASTED THIS MORNING. SO...SITUATION WILL HAVE TO BE MONITORED CLOSELY. BY FRIDAY/SATURDAY...THE OFFSHORE GRADIENTS START TO WEAKEN AS THE UPPER HIGH WEAKENS. SO...WILL EXPECT SOME COOLER TEMPS NEXT WEEKEND...BUT STILL WARMER THAN NORMAL CONDITIONS THROUGH THE PERIOD. && .AVIATION...11/1230Z. STRATUS WDSPRD IN CSTL AND VLYS THIS MORNING. WITH INCREASING ONSHORE GRADS...CIGS WILL LIKELY BE SLOW TO CLEAR IN THE VALLEYS...AND PROBABLY WILL NOT CLEAR NEAR THE COAST. KLAX...MVFR CIGS THIS MORNING. DO NOT EXPECT CIGS TO SCATTER OUT THIS AFTERNOON. CONFIDENCE IS LOW TO MODERATE. TYPICAL SEABREEZE NEAR 10 KT THIS AFTERNOON. KBUR...EXPECT IFR CIGS TO BECOME MVFR BY MID OR LATE MORNING. CIGS SHOULD SCATTER OUT AROUND 21Z OR 22Z. CONFIDENCE ON CLEARING IS LOW TO MODERATE. NO WIND ISSUES WITH TYPICAL S TO SE WINDS AROUND 10 KT THIS AFTERNOON. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...THOMPSON AVIATION...BRUNO WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1050 AM EDT SUN MAY 11 2008 .SYNOPSIS... WEAK HIGH PRESSURE OVER THE AREA EARLY THIS MORNING WILL RECEDE EAST. COMPLEX LOW PRESSURE WILL APPROACH FROM THE WEST TODAY, CONSOLIDATE OFF THE NORTHERN MID-ATLANTIC COAST EARLY ON MONDAY, AND THEN MOVE SLOWLY OUT TO SEA. HIGH PRESSURE IS FORECAST TO BUILD INTO OUR REGION FROM THE WEST FOR THE MID-WEEK PERIOD. A COLD FRONT IS EXPECTED TO FOLLOW FOR FRIDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HAVE MADE SOME MINOR ADJUSTMENTS TO CLOUD COVER AND POPS (LOWER ACROSS THE NORTH) BASED ON CURRENT RADAR AND SATELLITE IMAGERY AND THE BEGINNINGS OF THE 12Z MODEL DATA. ALL IN ALL, CURRENT FCST LOOKS GOOD. AFTER A SUNNY START TO THE DAY, CLOUDS SHOULD BEGIN TO INVADE FROM THE WEST AND SOUTHWEST. THE GFS AND THE ECMWF ARE A BIT QUICKER TO BRING PRECIPITATION INTO THE AREA THAN THE NAM. INITIALLY, WE`RE DEALING WITH ISENT LIFT PRECIP AT AROUND I300. THE SYSTEM RESPONSIBLE, AS NOTED IN PREVIOUS DISCUSSIONS, IS A VIGOROUS MID LEVEL TROF THAT IS IN THE PROCESS OF CUTTING OFF AS A STRONG UPPER LEVEL JET DROPS INTO ITS BASE. THE MID LEVEL LOW WILL BE MOVING INTO THE UPPER OHIO RIVER VALLEY BY THE END OF THE DAY, AND IT WILL BEGIN TO TRANSFER ENERGY AT THE SURFACE FROM A PRIMARY LOW NEAR THE PARENT MID LEVEL SYSTEM TO A SECONDARY LOW OVER VIRGINIA. WE HAVE MAINTAINED CONTINUITY ON TEMPERATURES. WINDS ARE EXPECTED TO BEGIN TO PICK UP OUT OF THE EAST OR SOUTHEAST DURING THE AFTERNOON, WHICH MAKES CONTINUITY SEEM LIKE A GOOD IDEA, AND THE FIRST CHANCE OF PRECIP SHOULD BE LATER IN THE AFTERNOON OVER THE SOUTHWESTERN PART OF THE FORECAST AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE SYSTEM WILL GENERATE A FAIRLY STRONG WIND FIELD, CARRY GOOD MID AND UPPER LEVEL DYNAMICS, GENERATE GOOD LOWER LEVEL FRONTOGENESIS, AND PERHAPS CARRY WITH IT SOME ELEVATED INSTABILITY. THE STRONG AND FAIRLY DEEP WINDS ABOVE THE SURFACE AND OFF THE OCEAN SHOULD CARRY AS MUCH ATLANTIC MOISTURE AS IS POSSIBLE, ALTHOUGH, AGAIN, WE HAVE A HARD TIME SEEING VERY HIGH H8 DEWPOINTS IN OUR REGION IN THE MORE MOIST GFS. THE GFS CARRIES 5 DEG C VALUES AS FAR NORTH AS ABOUT PHL AND CARRIES 8 DEG C VALUES INTO OUR FAR SOUTHERN ZONES. FURTHER TO THE NORTH, MORE REMOVED FROM THE SYSTEM, H8 DEW POINTS ARE EVEN LOWER. WITHOUT THE POSSIBILITY OF SOME CONVECTION, WHICH IS DEPICTED /AS ELEVATED CONVECTION/ A BIT MORE EMPHATICALLY IN THE GFS THAN THE NAM, WE WOULD BE TEMPTED TO UNDERCUT MODEL QPF A BIT AS THE MODELS HAVE A HIGH BIAS IN NON- CONVECTIVE EVENTS. HOWEVER, IT IS THE FEAR OF ELEVATED CONVECTION THAT KEPT US FROM DOING THAT. THAT MAKES FOR SOME RESPECTABLE PRECIPITATION AMOUNTS OVER ABOUT THE SOUTHERN HALF TO TWO-THIRDS OF THE AREA. WE INCLUDE A HYDRO SECTION BELOW. THE WIND FIELDS SHOW A CONSIDERABLE AMOUNT OF SHEAR, AND WE HOPE WE ARE CORRECT THAT ANY CONVECTION WOULD BE ALOFT. THAT IS WHAT THE SURFACE-BASED STABILITY PROGS SHOW, AND THAT IS HOW SPC AND WE ARE PLAYING IT. WINDS ALSO WILL BEGIN STRENGTHEN SUFFICIENTLY, FIRST OUT OF THE EAST TO SOUTHEAST TONIGHT, THEN OUT OF THE NORTHEAST ON MONDAY, TO CAUSE SOME TIDAL CONCERNS AS NOTED BELOW. IT IS POSSIBLE, AFTER THE TRANSFERENCE OF ENERGY AT THE SURFACE IS COMPLETE, THAT THE SYSTEM WOULD WIND UP ENOUGH ON MONDAY TO EVENTUALLY CAUSE US TO ISSUE A WIND ADVISORY, AT LEAST ALONG THE COAST, BUT BUFKIT FROM THE GFS LOOKS MARGINAL AND WE HAVE PASSED ON THAT FOR THE TIME BEING. THE CONSOLIDATED SYSTEM EXITS SLOWLY ON MONDAY, PERHAPS A BIT TOO SLOWLY AS DEPICTED BY THE NAM, AND THE BULK OF THE SIGNIFICANT PRECIPITATION SHOULD BE OVER WITH BEFORE EVENING. STABILITY PROGS, AT THE SURFACE AND ALOFT, INDICATE THAT THE THREAT OF CONVECTION MAY BE OVER WITH EARLY ON MONDAY, AND WE`RE NOT CARRYING ANY MENTION OF THUNDER AFTER TONIGHT FOR NOW. GRADUAL IMPROVEMENT IS FORECAST OVER LAND ON MONDAY NIGHT AND TUESDAY. AGAIN, CONTINUITY ON TEMPERATURES WAS MOSTLY ACCEPTED. WE DID ACTUALLY LOWER THE MONDAY MAXES OVER ALL BUT THE FAR SOUTHERN ZONES. SOUNDINGS FROM THIS RUN DON`T SHOW ANY PRECIP TYPE CONCERNS, BUT WE`LL CONTINUE TO WATCH THAT. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AT MID WEEK, WE ARE EXPECTING TO SEE THE UPPER LOW TAKING ITS TIME MOVING OUT TO SEA. MEANWHILE, AN UPPER RIDGE AXIS IS FORECAST TO EXTEND FROM THE GULF COAST UP INTO THE GREAT LAKES REGION ON TUESDAY NIGHT. AS THE LOW DRIFTS EASTWARD, SO WILL THE RIDGE. THE RIDGE AXIS IS EXPECTED TO PASS OVER OUR REGION FROM WEDNESDAY NIGHT INTO THURSDAY. AN UPPER LEVEL TROUGH IS FORECAST TO DIG INTO THE EASTERN STATES ON FRIDAY AND SATURDAY. A SURFACE COLD FRONT, ASSOCIATED WITH THE UPPER TROUGH, SHOULD PASS THROUGH OUR REGION ON FRIDAY NIGHT. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE OVER THE AREA WILL MOVE OFFSHORE THIS MORNING. LIGHT WEST WINDS...OR CALM WINDS...WERE ALLOWING FOR SOME RADIATIONAL COOLING EARLY THIS MORNING, AND FOG HAS WAFTED IN AND OUT AT KRDG. A COUPLE OF OTHER PLACES MAY HAVE SOME BRIEF IFR VISIBILITIES IN FOG, OTHERWISE CIRRUS WILL BE INCREASING FROM THE WEST-SOUTHWEST AS THE MORNING WEARS ON. LOW PRESSURE WILL APPROACH FROM THE OHIO VALLEY TODAY AND WEAKEN AS SECONDARY DEVELOPMENT TAKES PLACES ALONG THE VIRGINIA CAPES LATE TODAY AND EARLY TONIGHT. WITH THE DEVELOPING ONSHORE FLOW AND INFLUX OF MID AND THEN LOW LEVEL MOISTURE, CEILINGS WILL GRADUALLY LOWER TO MARGINAL VFR LATER THIS AFTERNOON, WITH RAIN DEVELOPING AS THE COLUMN MOISTENS LATE TODAY OR MORE LIKELY THIS EVENING, PROBABLY FROM WEST-SOUTHWEST TO EAST-NORTHEAST. LIGHT WINDS (WITH A WESTERLY COMPONENT) EARLY THIS MORNING WILL BACK AROUND TO EAST OR EAST-SOUTHEAST AND STRENGTHEN AS THE STORM SYSTEM NEARS. AN INCREASING PRESSURE GRADIENT MAY BECOME TIGHT ENOUGH TO ALLOW FOR GUSTS TO OCCUR FROM ABOUT MID AFTERNOON ON, ESPECIALLY FROM KPHL SOUTH AND EAST. A WIND SHEAR REMARK WAS ADDED LATE IN THE TAF VALID PERIOD AS LOW LEVEL WINDS WILL BE SCREAMING OUT OF THE EAST. SURFACE WINDS WILL BE GUSTY, BUT IT WAS FELT THAT A POINTER TO 45 TO 50 KNOT WINDS JUST OFF THE SURFACE WOULD BE BENEFICIAL. OUTLOOK... CONDITIONS WILL BE MARGINAL VFR IN STRATUS, WITH RAIN HEAVY AT TIMES AND FOG TONIGHT INTO MONDAY AS THE STORM IMPACTS THE REGION. WIDESPREAD RAIN AND GUSTY WINDS WILL NEGATIVELY IMPACT AIRCRAFT OPERATIONS SIGNIFICANTLY MONDAY. GRADUAL IMPROVEMENT IS EXPECTED LATE MONDAY NIGHT AND ESPECIALLY TUESDAY, BUT LINGERING NEGATIVE IMPACTS ARE LIKELY EVEN TUESDAY. HIGH PRESSURE IS FORECAST TO RETURN WEDNESDAY, HOWEVER A COLD FRONT MAY APPROACH FROM THE WEST THURSDAY WITH A CHANCE OF SHOWERS. && .MARINE... STRENGTHENING LOW PRESSURE APPROACHING FROM THE OHIO VALLEY TODAY WILL SHIFT ITS ENERGY TO THE VIRGINIA CAPES EARLY TONIGHT, WITH A GOOD OLD FASHIONED (MAY?) NOR`EASTER ON OUR HANDS. IT LOOKS LIKE A PRETTY GOOD BLOW WITH GOOD WAVE ACTION (OVER 10 FEET MONDAY AND MONDAY NIGHT), SO ANY SUNDAY PARTY BOATERS SHOULD PLAN ON RETURNING THIS AFTERNOON OR EARLY TONIGHT. MODEL OUTPUT LENT CONFIDENCE TO THE FORECAST, AS MODELS WERE CONSISTENT FROM PREVIOUS RUNS AND THERE WAS LITTLE SPREAD IN MODEL SOLUTIONS. FIRST, UPPER DELAWARE BAY: WINDS MAY GUSTS AT TIMES TO 35 KNOTS TONIGHT INTO TUESDAY, BUT ON THE WHOLE IT WAS THOUGHT THAT THIS WOULD BE A MINORITY OF THE TIME, SO THE SMALL CRAFT ADVISORY WAS LEFT INTACT AND EXTENDED THROUGH 10Z TUESDAY. THE INHERITED GALE WARNING ON THE SOUTHERN OCEAN WATERS WAS ALSO CONTINUED, AND LIKEWISE EXTENDED THROUGH 10Z TUESDAY (OUR 4TH PERIOD). HOWEVER, WE DID BACK UP THE STARTING TIME A COUPLE OF HOURS FROM 22Z TODAY TO 00Z MONDAY. THE NORTHERN OCEAN WATERS WERE ALSO BROUGHT INTO A GALE WARNING AT THIS TIME, AS THE TIGHTEST GRADIENT APPEARS TO SHIFT TO THE NORTH TONIGHT AND LINGER MONDAY. SO, THE STARTING TIME WAS A FEW HOURS AFTER THE SOUTHERN WATERS, ALLOWING FOR SOME TIME FOR THE GRADIENT TO BECOME COMPRESSED FURTHER NORTH. THIS TOO WILL EXTEND THROUGH 10Z TUESDAY. WAVES IN THE 8 TO 12 FOOT RANGE ON THE OCEAN WERE PRETTY MUCH CONTINUED, ALTHOUGH WAVEWATCH HAD A LITTLE HIGHER SOLUTION FOR A FEW TIME PERIODS MONDAY. FOR THE OUTLOOK, HIGH PRESSURE SHOULD FOLLOW FOR THE MIDDLE OF THE COMING WEEK, HOWEVER A COLD FRONT IS LIKELY TO APPROACH THURSDAY. && .HYDROLOGY... WE ARE EXPECTING AROUND AN INCH OR SO OF RAINFALL JUST NORTH OF THE ELEVATED CONVECTION AREA, WHICH IS TO SAY FROM NORTH OF READING TO NORTH OF TRENTON AND JUST NORTH OF INTERSTATE 195. AS WE MOVE FURTHER SOUTH, THE THREAT OF ELEVATED CONVECTION AND THE AMOUNT OF AVAILABLE MOISTURE INCREASES. WE COULD EASILY SEE AREAS WITH IN EXCESS OF TWO INCHES OVER MUCH OF THE DELMARVA AND FAR SOUTHERN NEW JERSEY, BUT BASED ON HEADWATER GUIDANCE /FFH/ AND FLASH FLOOD /FFG/, THESE AMOUNTS WOULDN`T CAUSE ANYTHING OTHER THAN POOR-DRAINAGE OR ROADWAY FLOODING. THE AREA OF CONCERN IS FAR SOUTHEASTERN PENNSYLVANIA, NORTHERN DELAWARE AND NORTHEAST MARYLAND, WHERE FFH AND/OR FFG VALUES WOULD BE WITHIN REACH ONCE WE APPROACH TWO INCHES. WE THEREFORE HAVE ISSUED A FLOOD WATCH. && .TIDES/COASTAL FLOODING... THE DECISION WAS MADE TO ISSUE A COASTAL FLOOD ADVISORY FOR WIDESPREAD MINOR TIDAL FLOODING FOR THE HIGH TIDE CYCLE LATE TONIGHT ON THE OCEAN FRONT (AND ADJACENT BACK BAYS), AND ALSO TO ISSUE A COASTAL FLOOD WATCH FOR THE SAME AREAS FOR MONDAY AND MONDAY NIGHT AS SURGE GUIDANCE PAINTS SIGNIFICANT TIDE DEPARTURES. ITS POSSIBLE THAT LINGERING EFFECTS WILL OCCUR TUESDAY AS WELL, BUT SINCE THAT`S WAY OUT ON THE TIME HORIZON, THAT CAN BE LEFT FOR A LATER DAY. AS THE DEVELOPING LOW PRESSURE AREA APPROACHES THIS AFTERNOON AND AFFECTS THE AREA TONIGHT THROUGH TUESDAY, BOTH THE NGM AND AVIATION STORM SURGE GUIDANCE SHOW PRONOUNCED POSITIVE ANOMALIES, ESPECIALLY MONDAY AND MONDAY NIGHT. STARTING OFF TONIGHT, ONLY MINOR TIDAL FLOODING IS FORESEEN FOR TONIGHT, BUT SINCE CONFIDENCE IS HIGH THAT IT WILL BE WIDESPREAD (AS MODELS HAVE BEEN CONSISTENT RUN-TO-RUN AND MODEL-TO-MODEL), IT WAS THOUGHT TO ISSUE THE ADVISORY NOW SO AS TO PROVIDE GOOD LEAD TIME. AN ADVISORY IS ALSO LIKELY TO BE NEEDED FOR DELAWARE BAY AND THE TIDAL PORTIONS OF THE DELAWARE RIVER MONDAY (MORNING), BUT THAT CAN BE ADDRESSED BY LATER SHIFTS. THE AFTERNOON HIGH TIDE CYCLE ON THE OCEAN FRONT IS THE LOWER OF THE TWO DAILY HIGH TIDES, WHICH MAY BE SOMEWHAT OF A SAVING FACTOR MONDAY; HOWEVER, SOME FORECASTS FOR MONDAY NIGHT ARE A BIT LOWER THAN THEY WERE FOR MONDAY AFTERNOON, ALTHOUGH ITS NOT CLEAR WHY THIS WOULD BE SO AS THE WINDS SHOULD STILL BE FROM A FAVORABLE NORTHEAST DIRECTION AND STILL QUITE STRONG. LATER MODEL RUNS MAY SHOW EQUAL ANOMALIES, SO THE DECISION WAS MADE THAT MONDAY NIGHT MAY HAVE ONLY SLIGHTLY LESS OR EVEN THE SAME EFFECTS AS MONDAY, AND A WATCH WOULD BE WARRANTED FOR BOTH TIME FRAMES SINCE THERE COULD BE AREAS OF MODERATE TIDAL FLOODING. AS INFORMATION CRYSTALLIZES LATER TODAY AND TONIGHT, PERHAPS THE WATCH COULD BE TRANSFORMED INTO AN ADVISORY IF WATCH/WARNING CRITERIA NO LONGER APPEAR TO BE MET. OR, HEY, MAYBE A WARNING WILL BE NEEDED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR PAZ067-070-071. NJ...COASTAL FLOOD WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR NJZ012>014-020-022>027. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT MONDAY FOR NJZ012>014-020-022>027. DE...COASTAL FLOOD WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR DEZ003-004. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT MONDAY FOR DEZ003-004. FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR DEZ001. MD...FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR MDZ008. MARINE...GALE WARNING FROM 8 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ431-452>455. GALE WARNING FROM 11 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ450-451. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT TUESDAY FOR ANZ430. && $$ SYNOPSIS...DELISI NEAR TERM...DELISI/NIERENBERG SHORT TERM...DELISI LONG TERM...IOVINO AVIATION.../ MARINE.../ HYDROLOGY...DELISI TIDES/COASTAL FLOODING.../
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1026 AM EDT SUN MAY 11 2008 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST EARLY THIS AFTERNOON ALLOWING FOR A POTENT STORM SYSTEM TO APPROACH FROM THE OHIO VALLEY. THIS SYSTEM WILL PASS THROUGH OUR REGION OVERNIGHT AND IT WILL SLOWLY MOVE OFF THE MID-ATLANTIC COAST MONDAY. SIGNIFICANT RAINFALL IS EXPECTED FROM THIS STORM SYSTEM WITH THE HEAVIEST RAIN EXPECTED LATER THIS AFTERNOON THROUGH TONIGHT. HIGH PRESSURE WILL SLOWLY BUILD IN BEHIND THIS STORM FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WATER VAPOR LOOP SHOWS A VIGOROUS UPPER LOW TRANSLATING EAST OVER THE MIDWEST. A DRY SLOT IS INTRUDING OVER THE TENNESSEE VALLEY. ACARS 400-250MB WIND OBSERVATIONS SHOW A 110-150KT CYCLICALLY CURVED JET FROM THE PLAINS INTO THE CENTRAL APPALACHIANS. 11Z SURFACE ANALYSIS PLACED A 985MB OCCLUDED CYCLONE IN EAST CENTRAL ILLINOIS. THE OCCLUDED BOUNDARY EXTENDED SOUTHEAST INTO NORTHERN ALABAMA...WITH A COLD FRONT CONTINUING SOUTHWEST ACROSS SOUTHERN TEXAS. A WARM/STATIONARY BOUNDARY STRETCHED EAST FROM CENTRAL ALABAMA THROUGH SOUTHERN GEORGIA. RIDGING IS OCCURRING EAST OF THE APPALACHIANS WITH A COASTAL BOUNDARY BEGINNING TO DEVELOP ALONG THE EASTERN CAROLINAS. A PRE-FRONTAL TROUGH WAS NOTED 50-100 MILES AHEAD OF THE OCCLUDED BOUNDARY. FORECAST TIMING REMAINS ON TRACK. AS THE UPPER LEVEL RIDGE MOVES TO THE EAST AND HEIGHTS FALL...LOWER LEVEL ISENTROPIC LIFT WILL INCREASE ABOVE THE BOUNDARY WELL SOUTH ACROSS THE EASTERN GULF STATES. THIS WILL BE AIDED AS CONVECTION MOVES OFF THE SOUTHEAST CONUS COAST...AND SOUTHERLY FLOW RECOVERY INCREASES FOR THE REMAINDER OF THE DAY. STRONG CONVECTION ALONG THE UPPER LOW SHOULD WEAKEN AS IT MOVES ACROSS THE MOUNTAINS DURING THE LATE AFTERNOON...AS STABILITY INCREASES TO THE NORTHEAST ACROSS THE REGION. HAVE HOWEVER UPDATED THE EVENING FORECAST WITH FURTHER DISCUSSION BELOW. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... UPDATED THE FORECAST TO ADD THUNDER IN FOR THE SOUTHERN ZONES. SURFACE INSTABILITY SHOULD REMAIN WELL SOUTH OF THE AREA GIVEN THE FORECAST TRACK OF THE TRIPLE POINT LOW. THERE IS CURRENTLY UPSTREAM CONVECTION ALONG THE UPPER LOW. 03Z SREF INDICATES 50 PERCENT OR GREATER PROBABILITY OF MUCAPE (MOST-UNSTABLE) ACROSS SOUTHERN ZONES THIS EVENING AND EARLY TONIGHT. ANY CONVECTION OF COURSE WILL ALSO SERVE TO INCREASE RAIN RATES FOR INCREASED FLOOD THREAT. AS THE PRIMARY LOW PRESSURE SYSTEM MOVES INTO THE OHIO VALLEY...IT BEGINS TO TRANSFER ITS ENERGY TO A DEVELOPING LOW CENTER OVER SE VIRGINIA. THE SECONDARY LOW PRESSURE IS EXPECTED TO MOVE UP THE CHESAPEAKE BAY OVERNIGHT. AS THE DIFFLUENCE ALOFT MOVES EASTWARD...HELPING TO CREATE STRONG LIFT...THE HEAVY RAINFALL IS EXPECTED TO BEGIN SPREADING EAST OF THE BLUE RIDGE MOUNTAINS. BY THIS TIME...PW WATER VALUES ARE NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR AS MOISTURE IS TRANSPORTED FROM THE GULF OF MEXICO AND FROM THE ATLANTIC OCEAN. THE EASTERLY FLOW WILL ALSO HELP TO INCREASE UPSLOPE ALONG THE BLUE RIDGE MOUNTAINS. AREAS MAINLY ALONG AND EAST OF THE BLUE RIDGE MOUNTAINS RECEIVED ANYWHERE FROM ONE TO THREE INCHES OF RAINFALL WITH THE THU/FRI SYSTEM. FLASH FLOOD GUIDANCE VALUES ARE PARTICULARLY LOW IN THIS AREA...WITH VALUES AROUND/BELOW AN INCH FOR 6 HOUR TOTALS FOR THE METRO BALTIMORE AND DC AREAS. 6 HOUR VALUES FOR THE SUBURBS ARE UNDER/AROUND 2 INCHES. THIS AREA IS THE MOST VULNERABLE FOR FLOODING WITH THE SUNDAY NIGHT/MONDAY SYSTEM. RAINFALL TOTALS OF TWO TO THREE INCHES WILL BE LIKELY IN THE AREA...WHERE SOILS REMAIN SATURATED. WEST OF THE BLUE RIDGE...6 HOUR FFG RANGES FROM TWO TO THREE INCHES. THIS SYSTEM IS EXPECTED TO PRODUCE ONE TO THREE INCHES OF RAINFALL IN THIS AREA. BELIEVE THE EARLIER START TIME FOR THE SW PORTION OF THE CWFA STILL LOOKS GOOD. WILL BE MAKING NO CHANGES TO THE FLOOD HEADLINE. THIS SYSTEM WILL HAVE THE POTENTIAL TO PRODUCE RIVER FLOODING AND FLOODING OF STREAMS/CREEKS IN THE URBAN CORRIDOR. SOILS...ESPECIALLY EAST OF THE BLUE RIDGE...REMAIN SATURATED AND ANY ADDITIONAL RAINFALL WILL ONLY CREATE RUN OFF. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE STRONG COASTAL STORM WILL SLOWLY MOVE OFF THE DELMARVA PENINSULA MONDAY MORNING AND OUT TO SEA DURING THE AFTERNOON. DESPITE THE FACT THAT THE LOW WILL BE SLOWLY MOVING AWAY FROM THE REGION...PLENTY OF MOISTURE FROM THE ATLANTIC WILL RAP AROUND THE LOW KEEPING CLOUDS ALONG WITH MORE RAIN ACROSS MOST OF THE REGION. STRONG PRESSURE GRADIENT BETWEEN THIS STORM AND HIGHER PRESSURE TO THE WEST WILL BRING BREEZY CONDITIONS. THIS COMBINED WITH THE CLOUDS AND RAIN WILL MAKE IT FEEL CHILLY. WITH A STRONG NORTHERLY FLOW IN PLACE...MAX TEMPERATURES WILL ONLY RANGE FROM THE MID 40S IN THE POTOMAC HIGHLANDS TO THE LOWER 50S IN THE WASHINGTON AND BALTIMORE AREAS...TO THE LOWER 60S ACROSS PORTIONS OF CENTRAL VIRGINIA. THIS IS ABOUT 15 TO 20 DEGREES BELOW CLIMO. HIGH PRESSURE WILL SLOWLY BUILD TOWARDS THE REGION MONDAY NIGHT AND TUESDAY BRINGING A RETURN OF DRIER CONDITIONS AND MORE SUNSHINE FOR TUESDAY. MAX TEMPERATURES TUESDAY WILL BE MUCH CLOSER TO CLIMO THANKS TO THE SUNSHINE. HIGH PRESSURE WILL SLOWLY DRIFT OFF THE MID-ATLANTIC COAST WEDNESDAY AND THE NEXT COLD FRONT WILL APPROACH FOR THURSDAY. STILL SOME UNCERTAINTY AS TO EXACTLY HOW THIS WILL PLAY OUT GIVEN THE FACT IT IS STILL SEVERAL DAYS AWAY. HOWEVER...MOST GUIDANCE IS IN AGREEMENT THAT THE FRONT STALLS OVER THE CWA THURSDAY AND A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT AND PASSES THROUGH THURSDAY NIGHT INTO FRIDAY. LEFT CHANCE POPS IN FOR THE LATTER PART OF THE WEEK INTO EARLY NEXT WEEKEND. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... SUB VFR CONDITIONS EXPECTED BY THE MID AFTERNOON AT THE KCHO AND KMRB TERMINALS...AND BY LATE AFTERNOON AT THE REMAINDER OF THE TERMINAL SITES. CIGS ARE EXPECTED TO REMAIN AT IFR CONDITIONS OVERNIGHT IN THE HEAVIEST RAIN. A WIND SHIFT IS EXPECTED LATE TONIGHT AS STRONG LOW PRESSURE MOVES ACROSS THE MID ATLANTIC. MVFR/IFR CIGS AND VSBYS EXPECTED MONDAY BEHIND THE STORM SYSTEM ALONG WITH PERIODS OF RAIN. N/NW WIND GUSTS AROUND 30 KT ARE POSSIBLE ESPECIALLY DURING THE LATE MORNING AND AFTERNOON HOURS. A RETURN OF VFR CONDITIONS ARE EXPECTED MONDAY NIGHT AS HIGH PRESSURE BUILDS CLOSER TO THE TERMINALS. VFR CONDITIONS WILL PERSIST THROUGH WEDNESDAY. THE NEXT SYSTEM WILL BRING A CHANCE FOR PRECIPITATION ALONG WITH MVFR/IFR CIGS AND VSBYS WEDNESDAY NIGHT AND THURSDAY. && .MARINE... WILL NOT BE CHANGING THE HEADLINES ALREADY IN EFFECT FOR THE TIDAL POTOMAC AND MARYLAND PORTION OF THE CHESAPEAKE BAY FOR THE NEAR TERM AND SHORT TERM PERIODS. BUFKIT SOUNDINGS AND LOCAL WRF MODEL SUPPORT AN INCREASING GRADIENT THIS AFTERNOON...WITH GUSTS UP TO 25 KT LIKELY. AS THE STRONG LOW PRESSURE APPROACHES FROM THE SW AND MOVES OVER THE CHESAPEAKE BAY...GALE CONDITIONS WILL OCCUR. GUSTS TO 35 KT WILL BE LIKELY. A STRONG STORM SYSTEM OVER THE WATERS EARLY MONDAY WILL SLOWLY MOVE OFF THE MID-ATLANTIC COAST BY MONDAY NIGHT. GUSTY N/NE WINDS WILL SHIFT TO THE N/NW BEHIND THIS STORM SYSTEM. A GALE WARNING IS IN EFFECT THROUGH MONDAY FOR THE LOWER TIDAL POTOMAC AND CHESAPEAKE BAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE UPPER TIDAL POTOMAC THROUGH MONDAY. A SMALL CRAFT ADVISORY WILL LIKELY HAVE TO BE ADDED FOR MONDAY NIGHT AND TUESDAY FOR THE TIDAL POTOMAC AND CHESAPEAKE BAY. HIGH PRESSURE WILL BUILD OVER THE WATERS TUESDAY NIGHT AND WEDNESDAY ALLOWING FOR WINDS TO DIMINISH. && .TIDES/COASTAL FLOODING... WATER LEVELS ARE STILL RUNNING ABOUT A FOOT ABOVE NORMAL. WATER LEVEL DEPARTURES ARE EXPECTED TO INCREASE TO 1 TO 2 FEET ABOVE ASTRONOMICAL PREDICATIONS THROUGH MONDAY AS STRONG LOW PRESSURE MOVES ACROSS THE CHESAPEAKE BAY. HAVE ISSUED A COASTAL FLOOD ADVISORY ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY WHERE THE STRONGEST AND MOST PERSISTENT FAVARABLE SOUTHEASTELY FETCH WILL TRAP WATER...DESPITE BEING AT A QUARTER MOON. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY AFTERNOON FOR DCZ001. MD...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR MDZ003-501-502. FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY AFTERNOON FOR MDZ004>007-009>011-013-014-016>018. COASTAL FLOOD ADVISORY UNTIL 10 AM EDT MONDAY FOR MDZ007-011- 014-017-018. VA...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR VAZ021-025>031-036>040-050-051-056. FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY AFTERNOON FOR VAZ041-042-052>055-057. WV...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR WVZ050>055-501>504. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR ANZ530>534-537. GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT MONDAY FOR ANZ530>534-537. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ535-536. && $$ SYNOPSIS...LASORSA NEAR TERM...ROGOWSKI SHORT TERM...ROGOWSKI/LISTEMAA LONG TERM...LASORSA AVIATION...ROGOWSKI/LISTEMAA/LASORSA MARINE...ROGOWSKI/LISTEMAA/LASORSA TIDES/COASTAL FLOODING...ROGOWSKI
AREA FORECAST DISCUSSION
NWS SEATTLE WA
830 AM PDT SUN MAY 11 2008 .SYNOPSIS...A COOL UPPER TROUGH WILL PRODUCE SCATTERED SHOWERS AND SUN BREAKS ACROSS WESTERN WASHINGTON TODAY. A WEAK RIDGE WILL BUILD INTO THE AREA MONDAY FOR A GENERALLY DRY DAY...WITH MORNING CLOUDS GIVING WAY TO SOME AFTERNOON SUNSHINE. A WARM FRONT WILL BRING A CHANCE OF RAIN TUESDAY. A STRONG UPPER RIDGE WILL BUILD OVER THE PACIFIC NORTHWEST FOR WARM SUNNY DAYS WEDNESDAY THROUGH FRIDAY. && .SHORT TERM...COULD BE THE LAST DUSTING OF SNOW IN THE CASCADES DOWN TO PASS LEVEL TODAY WITH A COOL UPPER LEVEL TROUGH OVER THE REGION TODAY. A LITTLE NEW SNOW ON THE TREES ON THE PASS WEBCAMS...MAINLY ABOVE 3000FT. AN ACARS FREEZING LEVEL OVER SEATTLE AT 8AM WAS 3200FT...WITH A 700MB TEMP OF -11C AND -29C AT 500MB. SO THERE IS JUST A SLIGHT CHANCE OF A THUNDERSTORM TODAY IN THE UNSTABLE AIR MASS...WILL WATCH THE RADAR ECHO TOPS TODAY. AT 8AM THE PSCZ ONLY HAS SHOWERS WITH TOPS TO 10 OR 15KFT...BUT THE PSCZ WILL SHIFT SOUTH INTO KING COUNTY BY AFTERNOON AND DAYTIME INSOLATION COULD HELP FIRE OFF A THUNDERSTORM. WILL HANDLE THAT WITH A NOWCAST OR TWO LATER IF IT HAPPENS. ZONE FORECASTS ARE IN THE BALLPARK WITH HIGHEST POPS IN THE PSCZ/NORTH OF SEATTLE WITH SCATTERED SHOWERS ELSEWHERE. NOT MUCH IN THE WAY OF SHOWERS OUTSIDE THE PSCZ...BUT THE HEATING OF THE DAY SHOULD FIRE OFF SCATTERED SHOWERS JUST ABOUT ANYWHERE OUTSIDE THE PSCZ IN THE AFTERNOON. THE NAM CONTINUES TO FORECAST DRY WEATHER MONDAY AND MONDAY NIGHT AS A WEAK RIDGE BUILDS IN...AND A WARM FRONT ON TUESDAY IS LOOKING INCREASINGLY WET IN THE MODELS SO WE PROBABLY WILL NOT GET BY WITH JUST A BRUSH BY/CHANCE OF RAIN FORECAST FOR THAT DAY. WILL PROBABLY MOVE THE POPS WAY UP FOR TUESDAY AND TUESDAY NIGHT AND EVEN KEEP A CHANCE OF RAIN OR DRIZZLE IN THE FORECAST FOR WEDNESDAY MORNING. SEEMS LATE IN THE YEAR FOR A WARM FRONT TO BE SO WET...BUT THAT IS WHAT THE MODELS SHOW. I DO THINK THAT WITH HEIGHTS RISING TO 580-585DAM WEDNESDAY AFTERNOON THAT THE PRECIP WILL DRY UP AROUND NOON AND MAX TEMPS WILL SPIKE NICELY INTO THE LOWER TO MID 70S BEHIND THE WARM FRONT IN CLEARING SKIES WED AFTERNOON. 19 .LONG TERM...THE 06Z GFS KEEPS THE STRONG WARM UPPER RIDGE OVER THE REGION THROUGH FRIDAY AND THEN WEAKENS IT AND SHIFTS IT INLAND SUNDAY...WITH HEIGHTS FALLING TO ARND 576DAM SUNDAY. THAT SUGGESTS A MARINE PUSH SATURDAY NIGHT. I EXPECT TO SHOW TWO VERY WARM DAYS THURSDAY AND FRIDAY...THEN DROP TEMPS JUST A LITTLE SATURDAY...AND FURTHER INTO SUNDAY AS IT BECOMES INCREASINGLY LIKELY THAT MARINE AIR WILL HAVE COOLED OFF WRN WA. HAVE ALREADY STARTED TO PUSH THE GRIDS THAT WAY SO ADJACENT OFFICES CAN SEE THAT...AND IF THE 12Z GFS AND ECMWF AGREE MAY EVEN ADD FIVE DEGREES TO THE CURRENT MAX TEMP FORECASTS FOR THU/FRI. 19 && .AVIATION....RADAR SHOWS THE PSCZ CURRENTLY LOCATED OVER SNOHOMISH COUNTY WITH LITTLE MOVEMENT NOTED. MODELS SHIFT THE WLY 850 MB FLOW MORE WNW-NW THROUGH THE DAY WHICH SHOULD ALLOW THE CONVERGENCE ZONE TO SHIFT SLOWLY SWD...PROBABLY INTO NORTH KING COUNTY 18-20Z...AND TO NEAR OR OVER THE KBFI/KSEA TERMINALS BY 22-24Z. THIS WILL CREATE WIND SHIFT ISSUES AND TEMPO MVFR CONDS WITH HEAVIER RAIN BANDS. THE PSCZ ZONE SHOULD WEAKEN AFTER MIDNIGHT BUT COULD LINGER NEAR THE KBFI/KSEA TERMINALS OVERNIGHT. THE NEXT TAF ISSUANCE WILL REFLECT THIS IDEA. .SEA...THE PSCZ WILL LIKELY SAG SWD THROUGH THE DAY...REACHING THE THE KSEA TERMINAL BETWEEN 22-24Z. SW WIND 6-10 KT....BECOMING VARIABLE ARND 10 KT OR LESS 22Z...THEN N 4-8 KT AFTER 00Z. EXPECT MVFR CONDS UNDER HEAVIER RAIN BANDS LATER TODAY AND TONIGHT. DTM && .MARINE...SLY GRADIENTS OVER THE INLAND WATERS ARE WEAKENING THIS MORNING...BUT MODERATELY STRONG ONSHORE FLOW WILL CONTINUE TO PRODUCE WLY SMALL CRAFT WINDS THROUGH THE STRAIT TODAY. WILL DROP ADVISORIES FOR ADMIRALTY/PUGET SOUND. SEAS WILL BE COMING UP TO 10 FEET OR SO ON THE COASTAL WATERS THIS AFTERNOON AS WINDS ARE DECREASING. GRAYS HARBOR BAR CONDITIONS BECOMING ROUGH DURING THE EBBS. DTM && .SEW WATCHES/WARNINGS/ADVISORIES... .SMALL CRAFT ADVISORY FOR THE COAST...AND STRAIT OF JUAN DE FUCA. .SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR. $$ WEATHER.GOV/SEATTLE