Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/30/12


AREA FORECAST DISCUSSION
NWS DENVER CO
1032 AM MDT FRI SEP 28 2012 .UPDATE...CORRECTION TO LINE 18 OF FIRST PARAGRAPH && .SHORT TERM...DENSE FOG ADVISORY WAS HOISTED EARLIER THIS MORNING FOR PORTIONS OF THE SOUTH PLATTE RIVER BASIN DOWN STREAM FROM THE DENVER METRO AREA. VISIBILITIES LESS THAN A QUARTER MILE WERE OBSERVED AT LONGMONT...GREELEY...FT MORGAN AND STERLING...TO NAME BUT A FEW LOCATIONS. HOWEVER IN THE PAST HOUR...THE TREND HAS BEEN UP AND THEREFORE THE ADVISORY MAY BE DROPPED SHORTLY. THE PATCHY FOG HANGING AROUND IN THE NORTH AND MIDDLE PARKS SHOULD ALSO BURN OFF THIS HOUR. OTHERWISE...THE REST OF THE FORECAST APPEARS ON TRACK. ALREADY BEGINNING TO SEE CUMULUS FORMING OVER THE FOOTHILLS AND HIGHER RIDGES ALONG THE CONTINENTAL DIVIDE. LATEST HRRR AND NAM RUNS INDICATE A SLOW BUT STEADY INCREASE IN CAPE OVER THE FRONT RANGE OVER THE NEXT FEW HOURS...WITH VALUES APPROACHING 400 J/KG BY MID-AFTERNOON. ON THE PLAINS THE FOG AND STRATUS BLANKETING MUCH OF THE SOUTH PLATTE BASIN DOWNSTREAM FROM DENVER SHOULD REMAIN STRONGLY CAPPED AT LEAST THOUGH MID-AFTERNOON. FARTHER SOUTH ALONG THE SPINE OF THE PALMER DIVIDE IN DOUGLAS...ELBERT AND NRN LINCOLN COUNTIES...MODELS ALSO SHOW CAPES ON THE RISE THROUGH THE AFTERNOON. THE HRRR INDICATES CAPES IN THE 500-1000 J/KG RANGE IN THIS AREA BY MID-AFTERNOON...WHEREAS THE 12Z/NAM ONLY INDICATES CAPES UP AROUND 400 J/KG. THAT SAID...THE ISOLATED TO SCATTERED POPS FOR THE FRONT RANGE MTNS/FOOTHILLS AND SOUTH PARK FOR THE AFTERNOON/ EARLY EVENING LOOK GOOD. THE ISOLATED POPS FOR THE I-25 URBAN CORRIDOR AND PALMER DIVIDE SHOULD ALSO SUFFICE. SEE LITTLE IF ANY CHANCE FOR PRECIP FARTHER OUT ON THE PLAINS. FOR THIS FORECAST UPDATE...WHICH HAS ALREADY BEEN ISSUED...ALSO MADE MINOR ADJUSTMENTS TO TEMPERATURE AND WINDS TO BETTER REFLECT THE LINGERING CLOUD COVER ON THE PLAINS. .AVIATION...VFR CONDITIONS ARE TO BE EXPECTED AT DENVER AREA AIRPORTS. AFTER 21Z TODAY...MAY STILL SEE A LIGHT RAIN SHOWERS OR WEAK T-STORM DRIFT SOUTHEAST OVER THE DENVER METRO AREA. GUSTY ERRATIC OUTFLOW AND LIGHTNING MOST LIKELY THE BIGGEST CONCERN WITH THESE PASSING CELLS. AS FOR WINDS...WINDS SPEEDS GENERALLY BELOW 10KTS WITH A GRADUAL SHIFT TO AN EAST-SOUTHEAST COMPONENT EARLY THIS AFTERNOON AND A RETURN TO OUR TYPICAL DRAINAGE WIND PATTERN NOT LONG AFTER SUNSET. && .HYDROLOGY...NO CONCERNS TODAY. && .PREV DISCUSSION... /ISSUED 420 AM MDT FRI SEP 28 2012/ SHORT TERM...FOG AND LOW CLOUDS HAVE DEVELOPED AS EXPECTED ACROSS MUCH OF NORTHEASTERN COLORADO BEHIND THE CLEARING LINE WHICH IS NEARING THE EASTERN BORDER. NORTH SIDE OF THE PALMER DIVIDE HAS WEAK DOWNSLOPE WINDS THOUGH KMNH HAS STILL CARRIED SOME THIN FOG AT TIMES. LIGHT SOUTH WINDS ARE ALSO KEEPING THE FOG FROM THICKENING AROUND DENVER SO FAR. ONLY WEAK HINTS OF A DENVER CYCLONE CIRCULATION...SO STILL SOME UNCERTAINTY ABOUT WHETHER DENVER WILL SOCK IN OVER THE NEXT FEW HOURS. AT THIS POINT MY BEST ESTIMATE IS THAT THE FOG WILL CONTINUE TO EXPAND ON ITS FRINGES INTO BOULDER COUNTY AND THE NORTHERN PART OF THE DENVER METRO AREA...BUT NOT MAKE A WHOLESALE SOUTHWARD PUSH. WEBCAMS LOOK TO BE MOSTLY IN THE QUARTER TO HALF MILE RANGE IN THE FOGGIER AREAS FROM LOVELAND OUT TO STERLING. THE VALLEY INVERSIONS WILL NOT HELP WITH THE INSTABILITY THIS AFTERNOON...EXPECTING LESS CONVECTION AND LATER TODAY THOUGH THERE WILL LIKELY STILL BE SOME SHOWERS OVER THE MOUNTAINS AND EVENTUALLY A FEW WEAK THUNDERSTORMS ON THE PLAINS. INHERITED POPS WERE HEDGED TOWARD THE PALMER DIVIDE AND CREST/EAST SLOPES OF THE FRONT RANGE AND THAT PATTERN SEEMS FINE. WITH MOISTURE MIXING OUT A BIT...CAPES ARE FORECAST TO BE AROUND 400 J/KG ALONG THE FRONT RANGE AND 800 J/KG OUT ON THE PLAINS. PRECIPITABLE WATER DROPPING DOWN TO 0.6 TO 0.7...STILL ENOUGH MOISTURE AND SLOW STORM MOTION FOR SOME HEAVY RAIN WITH A COUPLE OF THE STORMS...BUT NOT MUCH OF A FLOOD THREAT. EXPECT FASTER CLEARING TONIGHT WITHOUT MUCH TO KEEP CONVECTION GOING. I LOWERED THE MOUNTAIN LOWS FOR TONIGHT AS THERE SHOULD BE GOOD RADIATIONAL COOLING. LONG TERM...UPPER RIDGING TO THE WEST OF COLORADO WILL DOMINATE THE WEATHER FOR THE CWA SATURDAY THROUGH SUNDAY. WEAK ZONAL FLOW ON SATURDAY WILL GIVE WAY TO INCREASING NORTHERLY FLOW FOR SUNDAY AND SUNDAY NIGHT. WEAK DOWNWARD QG VERTICAL VELOCITY IS PROGGED FOR THE CWA SATURDAY THROUGH SUNDAY NIGHT. THE LOW LEVEL PRESSURE AND WIND FIELDS HAVE WEAK TROUGHING EAST OF THE MOUNTAINS SATURDAY AND SATURDAY NIGHT...SO THE BOUNDARY LAYER WINDS MAY HAVE A DOWNSLOPING COMPONENT TO THEM. THERE IS A WEAK SURGE OF COOLER AIR TO MOVE INTO THE FORECAST AREA SUNDAY...WITH WEAK NORTHERLY UPSLOPE FLOW PROGGED. FOR MOISTURE...THERE IS SOME IN THE MID AND UPPER LEVELS THROUGH THE FOUR PERIODS. THE LOWER LEVELS ARE DRY OVER THE WESTERN HALF OF THE CWA...WITH SOME 40S F DEW POINTS OVER THE EASTERN PLAINS ..ESPECIALLY ON SATURDAY. THE PRECIPITABLE WATER VALUES ARE IN THE 0.45 TO 0.60 INCH RANGE ALL FOUR PERIODS. THERE IS MORE MOISTURE PROGGED ON THE THIRD DAY...SUNDAY...ON THESE LATEST MODEL RUNS AS COMPARED TO YESTERDAY`S RUNS. THIS SEEMS TO BE THE CASE THE LAST TWO NIGHTS. THERE IS SOME CAPE PROGGED...MAINLY OVER THE PLAINS SATURDAY AFTERNOON. THE FAR NORTHEAST HAS VALUES UP TO 1000J/KG. THERE IS VERY LITTLE CAPE PROGGED ON SUNDAY. THE QPF FIELDS SHOW SMALL AMOUNTS OF MEASURABLE RAINFALL OVER THE CWA LATE IN THE DAY. SUNDAY LOOKS SIMILAR. FOR POPS WILL GO WITH 10-20%S FOR BOTH LATE DAY SATURDAY AND LATE DAY SUNDAY. FOR TEMPERATURES...SATURDAY`S HIGHS ARE PROGGED TO BE 2-3 C WARMER THAN TODAY`S. SUNDAY`S HIGHS ARE 0.5-1.5 C COOLER THAN SATURDAY`S. FOR THE LATER DAYS...MODELS HAVE A STRONG UPPER RIDGE TO THE WEST OF COLORADO WITH NORTHERLY FLOW ALOFT FOR THE CWA MONDAY AND TUESDAY. BY WEDNESDAY AND THURSDAY THE RIDGE MOVES SOUTH A BIT AND IS SOUTHWEST OF OUR STATE. THE FLOW ALOFT BECOMES NORTHWESTERLY FOR THE CWA THOSE TWO DAYS. THE GFS BRINGS A COLD FRONT DOWN TUESDAY NIGHT INTO WEDNESDAY...THE ECMWF DOES NOT. MOISTURE IS LACKING. NO POPS. WILL KEEP TEMPERATURES ABOVE SEASONAL NORMALS FOR NOW ALL FOUR DAYS. AVIATION...FOG NORTH OF THE DENVER AREA SHOULD EXPAND OVER THE NEXT COUPLE OF HOURS. STILL UNCERTAIN ABOUT HOW MUCH IT WILL IMPACT KDEN AND KBJC AS THEY LOOK TO BE ON THE EDGE. IF THE FOG DOES GET INTO KDEN RVRS WILL LIKELY STAY ABOVE 1000 FEET...BUT THERE COULD BE A COUPLE HOURS OF INSTRUMENT APPROACHES. FOG WILL BE GONE BY 15Z WITH VFR CONDITIONS THE REST OF THE DAY. HYDROLOGY...STILL SOME POSSIBILITY OF SOME HEAVY RAIN...HALF AN INCH IN UNDER AN HOUR...BUT NOT EXPECTING A FLOOD THREAT TODAY. && .BOU WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 11 AM MDT THIS MORNING FOR COZ043-044- 048. && $$ SHORT TERM...BAKER/GIMMESTAD LONG TERM....RJK AVIATION...BAKER/GIMMESTAD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
428 PM EDT FRI SEP 28 2012 .SYNOPSIS... RAIN WILL CONTINUE TO PLAGUE THE REGION OVERNIGHT AS A BROAD AREA OF LOW PRESSURE GRADUALLY LIFTS THROUGH THE REGION. ANTICIPATE ACTIVITY TO DIMINISH ACROSS INTERIOR NEW ENGLAND FOR SATURDAY IN THE FORM OF LIGHT SHOWERS AND DRIZZLE...WHILE THE EASTERN HALF CONTINUES TO BE IMPACTED BY RAIN. ACTIVITY SHOULD DIMINISH INTO SUNDAY AND SUNDAY NIGHT...WITH A BRIEF PERIOD OF HIGH PRESSURE FOR MONDAY INTO TUESDAY. ANOTHER DISTURBANCE IS POSSIBLE FOR THE MIDWEEK PERIOD...ESPECIALLY ALONG THE SOUTH COAST. HIGH PRESSURE RETURNS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 215 PM UPDATE... 28/15Z RAP MODEL HAD AN EXCELLENT HANDLE ON LOCATION AND TIMING OF PRECIPITATION ACROSS SOUTHERN NEW ENGLAND EARLY THIS AFTERNOON. HAD THE FRONTAL BOUNDARY BETWEEN NORWOOD AND MARSHFIELD MA... EXTENDING SOUTHWEST ACROSS RI TO BE BETWEEN WILLIMANTIC CT AND WESTERLY RI. THIS SHOULD BE THE FOCUS FOR THE HEAVIEST RAINFALL LATER THIS AFTERNOON AND EVENING. NOT MUCH SURFACE-BASED INSTABILITY TO WORK WITH ACROSS SOUTHERN NEW ENGLAND AND THE BEST WIND SHEAR REMAINS TO THE SOUTH AS WELL. WE HAVE NOTICED THE STRONGEST CONVECTION ACROSS CONTINUES TO BACK-BUILD ACROSS LONG ISLAND SOUND...ANOTHER INDICATION OF THE WEAK INSTABILITY ACROSS OUR REGION. THAT SAID...CANNOT COMPLETELY RULE OUT A THUNDERSTORM LATER THIS AFTERNOON ACROSS PORTIONS OF RI AND SOUTHEAST MA. PRECIPITABLE WATER CONTINUES TO BE OVER 2 INCHES...SO LOCALLY HEAVY DOWNPOURS WILL ALSO BE A POSSIBILITY. DO NOT HAVE A LOT OF FAITH IN THE TIMING DETAILS OF THE 28/12Z GUIDANCE. AS SUCH FAVORED A BLEND OF THE AVAILABLE GUIDANCE FOR TIMING THE PRECIPITATION. EXPECTING ONE AREA OF ISENTROPIC LIFT ON TE 295K AND 300K SURFACES TO MOVE OFFSHORE AND NORTH OF SOUTHERN NEW ENGLAND OVERNIGHT. THIS SHOULD BRING IN A RELATIVE DRY PERIOD LATE TONIGHT...ESPECIALLY ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND. TEMPERATURES NOT EXPECTED TO MOVE MUCH FROM PRESENT LEVELS. USED A BLEND OF THE MOS GUIDANCE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... EXPECTING A BROAD SURFACE TROUGH TO LONGER ACROSS THE COAST OF SOUTHERN NEW ENGLAND SATURDAY INTO SATURDAY NIGHT. CANNOT RULE OUT SOME AREAS OF RAIN AS THE AIRMASS DOES NOT DRY OUT APPRECIABLY. AGAIN CONFIDENCE IN THE TIMING IS LOW. DO EXPECT THE GREATEST RISK OF RAINFALL TO BE ALONG THE EAST COAST OF MA AND THE MA COASTAL WATERS. USED A BLEND OF THE MOS GUIDANCE FOR TEMPERATURES. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * SHOWERS DISSIPATING INTO MONDAY * BRIEF PERIOD OF HIGH PRES INTO TUESDAY * WET WX MAY PREVAIL FOR MUCH OF THE MIDWEEK * COOLER INTO THE WEEKEND WITH A PSBL WX DISTURBANCE MODEL ANALYSIS... THE 28/12Z GFS SEEMINGLY PROGRESSES SLIGHTLY FASTER THAN OTHER MDL SOLNS IN REGARDS TO H85 HEIGHTS...AND THERE ARE NOTABLE DIFFERENCES IN REGARDS TO SFC FEATURES IN COMPARISON TO SHORT-TERM GUIDANCE THRU MONDAY. WITH REGARDS TO THE SUNDAY-MONDAY FCST...LEANED TOWARDS A BLEND OF THE NAM/ECMWF GUIDANCE. THEREAFTER THE FCST PD REMAINS UNCERTAIN. IT WAS WITH YESTERDAYS MDL SOLNS THAT HIGH PRES WOULD HOLD IN PLACE KEEPING DISTURBANCES ASSOC WITH REMNANT TROPICAL ENERGY WELL OFFSHORE ALONG THE ATTENDANT STALLED SFC BOUNDARY. WITH TODAYS LATEST MDL SUITE...THE SFC BOUNDARY IS PROGGED TO RETROGRADE TOWARDS INTERIOR NEW ENGLAND AS LOW PRES LIFTS FROM THE GULF COAST FURTHER N INTO THE MID-ATLANTIC. CONFIDENCE WANES FOR THE MID-WEEK TIME FRAME ACCORDINGLY...AND FOR ALL DAYS THEREAFTER. ON A FINAL NOTE...THERE REMAINS A PERSISTENT SIGNAL OF HIGH PRES AND MUCH COOLER AND DRIER AIR BUILDING DOWN FROM CENTRAL CANADA. THERE IS STILL A HINT THAT A TASTE OF AUTUMN MAY BE ON THE NEAR HORIZON. DETAILS... SUNDAY... GREATER CONFIDENCE IS WEIGHTED TOWARDS THE 28/12Z NAM AND 28/0Z ECMWF. SOLNS HIGHLIGHT THE BEST CHCS FOR RAIN ACROSS S/E NEW ENGLAND IN PROXIMITY TO THE STALLED OFFSHORE FRONTAL BOUNDARY ALONG WHICH THE BETTER MOIST AXIS AND ATTENDANT FORCING RESIDE. WEAK WAVES OF LOW PRES ADVECTING NEWD ALONG THE BOUNDARY ADD AN ADDITIONAL FOCUS FOR ENHANCED RAIN FOR AFOREMENTIONED RGNS. AREAS OF HEAVY RAIN ARE PSBL WITH THE CHC FOR THUNDERSTORMS...ESPECIALLY ACROSS SERN NEW ENGLAND. LIKELY POPS ARE WARRANTED. AS FOR INTERIOR NEW ENGLAND THERE IS A GREATER AMNT OF UNCERTAINTY. MDL SOLNS CONTINUE TO KEY ON DRIER AIR ENTRAINING ALONG THE ERN PERIPHERY OF THE ERN GRT LKS NEARLY-STACKED CLOSED LOW...WITH 28/12Z NAM MDL SOUNDINGS EXHIBITING A FAIRLY DRY ATMOS INDICATIVE OF SCT-BKN CLOUD COVER AND VERY LITTLE CHC OF RAIN. WILL STILL INCITE SOME SLGT CHC POPS AS SHRTWV ENERGY PINWHEELS AROUND THE AFOREMENTIONED LOW AND CYCLONIC FLOW PREVAILS. OVERALL WLY FLOW WITH TEMPS PSBLY INTO THE UPR 60S-LOW 70S FOR THE CT VLY. SUNDAY NIGHT INTO MONDAY... NEARLY-STACKED CLOSED LOW LIFTS NEWD INTO THE ST LAWRENCE RVR VLY. WHILE DRIER AIR CONTINUALLY ENTRAINS TO THE REAR OF THE DEPARTING SYSTEM /ALLOWING SERN NEW ENGLAND TO DRY OUT AFTER DUSK/...IT IS PLAUSIBLE THAT AN INVERTED TROF SWEEPING ACROSS THE RGN WITH DEPARTURE OF THE LOW WILL BE THE FOCUS FOR ADDITIONAL SHOWER DEVELOPMENT...YET THE BETTER MOISTURE AVAILABILITY AND FORCING LOOK TO LIFT N OF THE FCST RGN PARENT WITH THE DEPARTING LOW. WILL INVOKE SLGT CHC POPS WITH TRENDS FOR GRADUAL CLEARING BY MONDAY MORNING. THE SPEED AT WHICH CONDITIONS IMPROVE REMAINS UNCERTAIN...BUT A BLEND OF THE 28/12Z NAM AND 28/0Z ECMWF SUFFICES. A MILD NGT ON TAP WITH CLOUDS AND MOISTURE LINGERING...LOOKING TO BE A WARM AND DRY DAY MONDAY WITH HIGHS INTO THE LOW 70S. W/SWLY FLOW PREVAILS. MONDAY NIGHT THROUGH THURSDAY... BOTH THE 28/12Z GFS AND 28/0Z ECMWF HAVE ALTERED THEIR APPROACH IN HANDLING THE REMNANTS OF TS MIRIAM /EAST-PACIFIC DISTURBANCE/ ACROSS MEXICO EWD ALONG THE GULF COAST AND LIFTING NEWD THRU THE LONG WAVE PATTERN INTO NEW ENGLAND. THE PRESENT SYNOPSIS IS FOR ATTENDANT ENERGY TO ELONGATE AGAINST THE WRN PERIPHERY OF THE STOUT RIDGE OF HIGH PRES ANCHORED OVER THE ATLANTIC. AN ATTENDANT WAVE OF SFC LOW PRES LIFTING CONCURRENTLY THRU THE MID-ATLANTIC DURING THIS PD ACTS TO DRAG THE STALLED OFFSHORE FRONTAL BOUNDARY /WHICH AT THIS POINT WAS THE FOCUS FOR ACTIVE WX ON SUNDAY/ NWD AS A WARM FRNT. WHILE IT IS LIKELY THAT MDL SOLNS WILL ALTER IN TIME...THERE REMAINS AN ENHANCED THREAT OF RAIN...POSSIBLY HEAVY AT TIMES...ALONG THE S COASTLINE OF NEW ENGLAND WHERE THE STALLED FRONTAL BOUNDARY SHALL RESIDE BY TUE NGT THRU THURS NGT ALONG AS ADDITIONAL WEAK WAVES OF LOW PRES WILL TRAVERSE ALONG THE AFOREMENTIONED FRONTAL BOUNDARY. FRIDAY ONWARD... THE 28/0Z ECMWF IS STILL KEYING UPON SOME INFLUENCE OF HIGH PRES BUILDING S/E OUT OF CENTRAL CANADA AS MID-WEEK SRN STREAM ENERGY IS PUSHED OUT BY A SLIGHT STRONG NRN STREAM DISTURBANCE. W/NWLY FLOW PREVAILS IN WAKE OF THE TWO USHERING MUCH COOLER AND DRIER AIR ACROSS THE RGN. CPC CONTINUES TO HINT AT SOME BELOW NORMAL TEMPS FOR THE CONUS IN ITS 8-14 DAY OUTLOOK. SOME HINT AMONGST THE FCST GUIDANCE FOR ANOTHER DISTURBANCE BY THE END OF THE WEEKEND INTO THE BEGINNING OF NEXT WEEK. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT SHORT TERM... THROUGH 00Z...MODERATE CONFIDENCE. TIMING OF RAIN AND LOWER CLOUDS CONTINUES TO BE PROBLEMATIC FOR SOME TERMINALS. DO EXPECT IFR CONDITIONS TO PREVAIL LATE THIS AFTERNOON ACROSS THE INTERIOR... WITH VFR TO MVFR CONDITIONS ACROSS THE CAPE AND ISLANDS. TONIGHT...MODERATE TO HIGH CONFIDENCE. ONE BATCH OF RAIN MOVES OFF...A SECOND MOVES UP FROM THE SOUTH. EITHER WAY...EXPECTING CIGS TO REMAIN MVFR WITH AREAS OF IFR IN RAIN AND FOG. VSBYS ALSO MVFR WITH AREAS OF IFR IN HEAVIER RAIN AREAS. SOME POTENTIAL FOR TSTMS TO DEVELOP...MAINLY ALONG THE SOUTH COAST AND THE COASTAL PLAIN. SATURDAY...MODERATE CONFIDENCE. COASTAL LOW PRESSURE PASSES AND MOVES OFF THROUGH THE GULF OF MAINE. DIMINISHING COVERAGE OF RAIN. VSBYS IMPROVE ESPECIALLY IN THE AFTERNOON. CEILINGS MAY IMPROVE...BUT LESS CERTAIN. POTENTIAL FOR LINGERING MVFR CIGS IN EASTERN MA DURING THE AFTERNOON. SATURDAY NIGHT...MODERATE CONFIDENCE. PREDOMINANTLY IFR CIGS ACROSS THE REGION WITH POCKETS OF MVFR CIGS. KBOS TAF...MODERATE CONFIDENCE. EXPECTING TERMINAL TO BOUND BETWEEN VFR/MVFR CONDITIONS AS RAINFALL INTENSITY CHANGES...WITH MVFR DOMINATING LATER THIS EVENING. MODERATE CONFIDENCE IN IFR CIGS OVERNIGHT WITH SLIGHTLY LOWER CONFIDENCE OF VLIFR AROUND MIDNIGHT INTO 29/12Z. KBDL TAF...MODERATE CONFIDENCE. PRIMARILY IFR TO START...WITH BRIEF PERIODS OF MVFR THIS AFTERNOON. FIRST BATCH OF RAIN MOVES OFF THIS AFTERNOON...THEN A SECOND AREA OF RAIN MOVES UP THE COAST TONIGHT. CEILINGS SHOULD HOLD AROUND 1000-1500 FEET THROUGH THE PERIOD. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY INTO MONDAY... MODERATE CONFIDENCE. INITALLY...MVFR/VFR CIGS SHOULD BE IMPACTING TERMINALS E OF THE CT RVR VLY WITH SHRA. MAY SEE SOME INTERMITTENT IFR VSBY IMPACTS. GRADUALLY THRU SUNDAY CONDITIONS WILL IMPROVE AS NLY FLOW VEERS OUT OF THE W/SW. CIGS LIFT AND VFR PREVAILS...YET THERE REMAINS A SLIGHT POSSIBILITY FOR RENEWED SHRA AND ATTENDANT IMPACTS SUNDAY NGT...LOW CONFIDENCE. AS FOR MONDAY...GRADUAL IMPROVEMENT CONTINUES. MAY SEE GUSTS UP TO 15-20 KTS OUT OF THE SW /UP TO 25 KTS PSBL FOR TERMINALS ALONG THE S COAST/. TUESDAY THROUGH WEDNESDAY... LOW TO MODERATE CONFIDENCE. ADDITIONAL WET WX DISTURBANCE TRANSLATE FROM THE MID-ATLANTIC NEWD JUST S OF NEW ENGLAND /OFFSHORE/. ANTICIPATING A STALLED FRONTAL BOUNDARY JUST S OF NEW ENGLAND RESULTING IN VRB WINDS ALONG THE S COAST...BUT A MORE N/NELY FLOW THRU THE INTERIOR. LOWEST OF CIGS ACCORDINGLY ALONG THE S COAST... HIGHER N INTO INTERIOR NEW ENGLAND. ANTICIPATING A MIX OF MVFR/VFR CIGS WITH SHRA. PERHAPS SOME VSBY IMPACTS. && .MARINE... CONTINUING SMALL CRAFT ADVISORIES FOR MOST OF THE COASTAL WATERS AS A LOW PRESSURE MOVES ACROSS THE REGION OVERNIGHT. COULD SEE SOME GUSTS UP TO 25 KT BEFORE THE CENTER OF THE LOW PRESSURE ARRIVES. THE EASTERLY FLOW COULD ALSO GENERATE 5 FT SEAS AS WELL...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. WINDS AND SEAS START TO DIMINISH LATE TONIGHT...AND SHOULD BE BELOW SMALL CRAFT ADVISORY LEVELS SATURDAY AFTERNOON. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY INTO MONDAY... AS SHOWERS LIFT OUT OF THE RGN AND SKIES BEGIN TO BREAK...WILL SEE AN ENHANCEMENT OF SWLY FLOW INTO MONDAY WITH GUSTS UP TO 25 KTS PSBL FOR THE S WATERS. WHILE VSBY WILL IMPROVE...WAVE HEIGHTS ARE EXPECTED TO BUILD UP TO 5 FT FOR THE S/SE WATERS. TUESDAY INTO WEDNESDAY... WAVE HEIGHTS OF 5 FT LESSEN ALONG THE S/SE WATERS GRADUALLY THRU TUES. WILL SEE A FRONTAL BOUNDARY LIFT N AND STALL JUST OFFSHORE OF NEW ENGLAND RESULTING IN LGT PREVAILING N/NELY FLOW. SHOWERS WILL BE ON THE INCREASE AS A SERIES OF DISTURBANCES TRANSLATE ALONG THE STALLED FRONTAL BOUNDARY...VSBY IMPACTS WITH HEAVIER SHOWERS WILL BE PSBL. PATCHY FOG ALSO PSBL. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ232>234. SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR ANZ231. SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR ANZ235-237- 255-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ250-251- 254. && $$ SYNOPSIS...BELK/SIPPRELL NEAR TERM...BELK SHORT TERM...BELK LONG TERM...SIPPRELL AVIATION...BELK/SIPPRELL MARINE...BELK/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
242 PM EDT FRI SEP 28 2012 .SYNOPSIS... HIGH PRESSURE MOVES EAST THROUGH THE MARITIMES TODAY WHILE LOW PRESSURE APPROACHES FROM THE WEST. THIS WILL BRING TWO PERIODS OF APPRECIABLE RAINFALL TO THE AREA TODAY AND TONIGHT. THIS LOW PRESSURE WILL EXIT THE REGION SATURDAY...BUT LOW CLOUDS AND SPOTTY DRIZZLE WILL LINGER. ANOTHER LOW PRESSURE WILL APPROACH FROM THE SOUTH SUNDAY NIGHT AND MONDAY...BRINGING MORE RAIN TO THE AREA. YET ANOTHER WEAK LOW MAY SCRAPE BY TO THE SOUTH DURING TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 215 PM UPDATE... 28/15Z RAP MODEL HAD AN EXCELLENT HANDLE ON LOCATION AND TIMING OF PRECIPITATION ACROSS SOUTHERN NEW ENGLAND EARLY THIS AFTERNOON. HAD THE FRONTAL BOUNDARY BETWEEN NORWOOD AND MARSHFIELD MA... EXTENDING SOUTHWEST ACROSS RI TO BE BETWEEN WILLIMANTIC CT AND WESTERLY RI. THIS SHOULD BE THE FOCUS FOR THE HEAVIEST RAINFALL LATER THIS AFTERNOON AND EVENING. NOT MUCH SURFACE-BASED INSTABILITY TO WORK WITH ACROSS SOUTHERN NEW ENGLAND AND THE BEST WIND SHEAR REMAINS TO THE SOUTH AS WELL. WE HAVE NOTICED THE STRONGEST CONVECTION ACROSS CONTINUES TO BACK-BUILD ACROSS LONG ISLAND SOUND...ANOTHER INDICATION OF THE WEAK INSTABILITY ACROSS OUR REGION. THAT SAID...CANNOT COMPLETELY RULE OUT A THUNDERSTORM LATER THIS AFTERNOON ACROSS PORTIONS OF RI AND SOUTHEAST MA. PRECIPITABLE WATER CONTINUES TO BE OVER 2 INCHES...SO LOCALLY HEAVY DOWNPOURS WILL ALSO BE A POSSIBILITY. DO NOT HAVE A LOT OF FAITH IN THE TIMING DETAILS OF THE 28/12Z GUIDANCE. AS SUCH FAVORED A BLEND OF THE AVAILABLE GUIDANCE FOR TIMING THE PRECIPITATION. EXPECTING ONE AREA OF ISENTROPIC LIFT ON TE 295K AND 300K SURFACES TO MOVE OFFSHORE AND NORTH OF SOUTHERN NEW ENGLAND OVERNIGHT. THIS SHOULD BRING IN A RELATIVE DRY PERIOD LATE TONIGHT...ESPECIALLY ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND. TEMPERATURES NOT EXPECTED TO MOVE MUCH FROM PRESENT LEVELS. USED A BLEND OF THE MOS GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... EXPECTING A BROAD SURFACE TROUGH TO LONGER ACROSS THE COAST OF SOUTHERN NEW ENGLAND SATURDAY INTO SATURDAY NIGHT. CANNOT RULE OUT SOME AREAS OF RAIN AS THE AIRMASS DOES NOT DRY OUT APPRECIABLY. AGAIN CONFIDENCE IN THE TIMING IS LOW. DO EXPECT THE GREATEST RISK OF RAINFALL TO BE ALONG THE EAST COAST OF MA AND THE MA COASTAL WATERS. USED A BLEND OF THE MOS GUIDANCE FOR TEMPERATURES. && .LONG TERM /SUNDAY THROUGH THURSDAY/... OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE MODEL SOLUTIONS GIVE GOOD RESULTS ON THE OVERALL UPPER LEVEL PATTERN...ESPECIALLY WITH THE MOVEMENT OF THE H5 CLOSED LOW OUT OF THE GREAT LAKES INTO NORTHERN NEW ENGLAND THROUGH THIS WEEKEND INTO EARLY NEXT WEEK. HOWEVER...MODELS STILL HAVING DIFFICULTIES WITH THE SURFACE FEATURES...THOUGH STILL SIGNALING UNSETTLED WEATHER INTO MONDAY. NOW THOUGH...SEVERAL MEMBERS INCLUDING THE ECMWF AND GGEM STARTING TO SIGNAL YET ANOTHER LOW TRYING TO RIDE OUT OF THE GULF COAST ACROSS THE REGION TUESDAY ON THE CONTINUED SW UPPER FLOW. NOTED THAT THE 00Z OP GFS RUN BECOMING AN OUTLIER BEYOND MONDAY WITH THIS LOW. LEANED TOWARD A GFS/EC/EC ENSEMBLE BLEND EARLY...THEN MORE TOWARD THE EC LATER IN THE PACKAGE. DETAILS... SUNDAY... STALLED FRONT MEANDERS ACROSS THE REGION WHILE A WEAK WAVE APPROACHES LATE SAT NIGHT/SUN. WENT ALONG WITH LOW LIKELY POPS ACROSS RI/SE MA WHERE BEST LIFT/LL MOISTURE ARE. WITH FAIRLY GOOD E-NE FLOW IN PLACE...HAVE MENTIONED PATCHY DRIZZLE FOR SAT NIGHT/EARLY SUN AS WELL. BEST PW/S REMAIN CLOSE TO CAPE COD AND OFFSHORE...AROUND 1.5 INCHES...BUT COULD STILL SEE A COUPLE OF BRIEF HEAVY DOWNPOURS ACROSS EASTERN AREAS WHEN BEST LIFT MOVES THROUGH. WINDS VEER AROUND TO S DURING SUNDAY...SO COULD SEE TEMPS RISE TO THE 60S...MAYBE TOUCHING 70 ACROSS THE CT VALLEY AWAY FROM BEST LIFT/LL MOISTURE FEED. SUNDAY NIGHT-MONDAY... GFS STARTS TO LINGER AWAY FROM MOST OTHER SOLUTIONS AS IT TRIES TO OPEN UP THE H5 CUTOFF FASTER THAN THE GGEM/ECMWF SOLUTIONS. STILL NOTING MAINLY A S-SW UPPER FLOW CONTINUING...ALONG WITH STALLED FRONT WAVERING CLOSE TO OR JUST S OF THE REGION. BOTH GGEM AND EC INDICATING ANOTHER WEAK WAVE MOVING ACROSS EASTERN AREAS LATE SUN NIGHT/MONDAY MORNING WITH ANOTHER ROUND OF SHOWERS AND PATCHY DRIZZLE/FOG. MAY START TO SEE CONDITIONS DRY OUT SOMEWHAT OVER W MA/N CENTRAL CT/SW NH DURING THE AFTERNOON. DAYTIME HIGHS MAY BE A FEW DEGS HIGHER THAN SATURDAY...POSSIBLY INTO THE LOWER 70S IN SOME SPOTS AS WINDS SHIFT TO S-SW AND PICK UP A BIT. MONDAY NIGHT AND TUESDAY... GGEM/ECMWF MODELS IN PRETTY GOOD AGREEMENT IN BRINGING YET ANOTHER WAVE ON FRONT...WHICH WILL REMAIN JUST S OF THE REGION. BIG QUESTION AT THIS POINT WILL BE HOW FAR N WILL THIS LOW TRACK OUT OF THE GULF COAST STATES. EC TRIES TO BRING LOW ACROSS CAPE COD DURING TUESDAY SO HAVE ADDED LOW CHANCE POPS FOR THE S COAST. LOW TO MODERATE CONFIDENCE ON THIS FEATURE AT THIS TIME...HOWEVER. TUESDAY NIGHT THROUGH THURSDAY... TIMING ISSUES ABOUND DURING THIS TIMEFRAME...AND EVEN HOW THE NORTHERN STREAM INTERACTS WITH SOUTHERN STREAM ENERGY. AT THIS POINT...HAVE KEPT SLIGHT CHANCE POPS GOING THROUGH AT LEAST WEDNESDAY AS EC AND GGEM TRY TO KEEP MOISTURE PLUME ACROSS MAINLY S COASTAL AREAS BUT UNCERTAIN IF THIS WILL SET UP AS WELL AS HOW FAR N. MAY DRY THINGS OUT ACROSS N MA/S NH DURING THURSDAY. RATHER LOW CONFIDENCE ON THIS PORTION OF THE FORECAST. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT SHORT TERM... THROUGH 00Z...MODERATE CONFIDENCE. TIMING OF RAIN AND LOWER CLOUDS CONTINUES TO BE PROBLEMATIC FOR SOME TERMINALS. DO EXPECT IFR CONDITIONS TO PREVAIL LATE THIS AFTERNOON ACROSS THE INTERIOR...WITH VFR TO MVFR CONDITIONS ACROSS THE CAPE AND ISLANDS. TONIGHT...MODERATE TO HIGH CONFIDENCE. ONE BATCH OF RAIN MOVES OFF...A SECOND MOVES UP FROM THE SOUTH. EITHER WAY...EXPECTING CIGS TO REMAIN MVFR WITH AREAS OF IFR IN RAIN AND FOG. VSBYS ALSO MVFR WITH AREAS OF IFR IN HEAVIER RAIN AREAS. SOME POTENTIAL FOR TSTMS TO DEVELOP...MAINLY ALONG THE SOUTH COAST AND THE COASTAL PLAIN. SATURDAY...MODERATE CONFIDENCE. COASTAL LOW PRESSURE PASSES AND MOVES OFF THROUGH THE GULF OF MAINE. DIMINISHING COVERAGE OF RAIN. VSBYS IMPROVE ESPECIALLY IN THE AFTERNOON. CEILINGS MAY IMPROVE...BUT LESS CERTAIN. POTENTIAL FOR LINGERING MVFR CIGS IN EASTERN MA DURING THE AFTERNOON. SATURDAY NIGHT...MODERATE CONFIDENCE. PREDOMINANTLY IFR CIGS ACROSS THE REGION WITH POCKETS OF MVFR CIGS. KBOS TAF...MODERATE CONFIDENCE. EXPECTING TERMINAL TO BOUND BETWEEN VFR/MVFR CONDITIONS AS RAINFALL INTENSITY CHANGES...WITH MVFR DOMINATING LATER THIS EVENING. MODERATE CONFIDENCE IN IFR CIGS OVERNIGHT WITH SLIGHTLY LOWER CONFIDENCE OF VLIFR AROUND MIDNIGHT INTO 29/12Z. KBDL TAF...MODERATE CONFIDENCE. PRIMARILY IFR TO START...WITH BRIEF PERIODS OF MVFR THIS AFTERNOON. FIRST BATCH OF RAIN MOVES OFF THIS AFTERNOON...THEN A SECOND AREA OF RAIN MOVES UP THE COAST TONIGHT. CEILINGS SHOULD HOLD AROUND 1000-1500 FEET THROUGH THE PERIOD. OUTLOOK...SUNDAY THROUGH TUESDAY... SUNDAY...MODERATE CONFIDENCE. MAINLY MVFR/VFR CIGS. SCT SHOWERS/PATCHY DRZL AND FOG ACROSS MOST OF THE REGION...WITH BEST CHANCE ACROSS RI/E MA LATE SAT NIGHT/SUN. LOW-MODERATE PROB OF IFR CIGS/VSBYS LATE SAT NIGHT IN FOG/DRZL PATCHES. SUNDAY NIGHT-MONDAY...MODERATE CONFIDENCE. EXPECT MVFR-VFR CIGS/VSBYS IN SCT SHOWERS/PATCHY DRZL/FOG. ANOTHER LOW MOVES ALONG PASSING FRONT LATE SUN NIGHT/MON MORNING WITH SHOWERS LIKELY ACROSS RI/E MA. LOCAL IFR VSBYS POSSIBLE IN ANY BRIEF HEAVY DOWNPOURS. SW WINDS MAY GUST TO UP TO 20 KT ON THE S COAST DURING MON. MONDAY NIGHT INTO TUESDAY...MODERATE CONFIDENCE. SHOULD BE MAINLY VFR MON NIGHT WITH PATCHY MVFR-IFR VSBYS IN PATCHY FOG. YET ANOTHER LOW MOVES S OF THE REGION...WHICH MAY BRING SCT SHOWERS ACROSS RI/SE MA WITH LOCAL MVFR CIGS/VSBYS. && .MARINE... TODAY... INCREASING SOUTHEAST WINDS AS LOW PRESSURE ROLLS ACROSS FROM THE OHIO VALLEY. WINDS JUST OFF THE SURFACE WILL REACH 20-25 KNOTS...WITH CONFIDENCE THAT SOME OR ALL OF THIS WILL REACH THE SURFACE THIS AFTERNOON...ESPECIALLY IN ANY RAIN. THE WIND WILL SERVE TO BUILD SEAS WITH 5 FOOT VALUES ON THE OUTER WATERS. SMALL CRAFT ADVISORY CONTINUES...FOR THE SOUTHERN WATERS THIS MORNING AND FOR MOST WATERS THIS AFTERNOON. TONIGHT... AS THE CENTER OF LOW PRESSURE MOVES UP OVER THE WATERS...THE DIMINISHING PRESSURE GRADIENT WILL ALLOW WINDS TO DIMINISH AS WELL. SMALL CRAFT ADVISORY CONTINUES...WITH SMALL ADJUSTMENTS TO ENDING TIMES AS THE WINDS AND SEAS DIMINISH OVERNIGHT. SATURDAY... WINDS AND SEAS DIMINISH WITH VALUES EXPECTED TO REMAIN BELOW SMALL CRAFT THRESHOLDS. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT THROUGH SUNDAY NIGHT...MODERATE CONFIDENCE. WINDS EXPECTED TO REMAIN BELOW 15 KT...MAINLY FROM THE E-NE THOUGH WILL BE SHIFTING AS LOW PRES MOVES ACROSS THE EASTERN WATERS SUNDAY NIGHT. SEAS WILL ALSO REMAIN BELOW SMALL CRAFT CRITERIA. VSBY RESTRICTIONS IN SCATTERED SHOWERS ALONG WITH PATCHY RAIN AND NIGHTTIME DRIZZLE. MONDAY AND TUESDAY...MODERATE CONFIDENCE. SW WINDS PICK UP ON MONDAY...GUSTS UP TO 20 KT. SEAS MAY BUILD TO 5 FT ON THE SOUTHERN OUTER WATERS. WINDS DIMINISH MON NIGHT INTO TUESDAY. ANOTHER LOW WILL SCRAPE ACROSS THE SOUTHERN WATERS TUE...WITH SOME VSBY RESTRICTIONS IN SCT SHOWERS/PATCHY FOG. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ232>234. SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR ANZ231. SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR ANZ235-237- 255-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ250-251- 254. && $$ SYNOPSIS...BELK/EVT NEAR TERM...BELK/EVT SHORT TERM...BELK LONG TERM...EVT AVIATION...BELK/EVT MARINE...BELK/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1024 AM EDT FRI SEP 28 2012 .SYNOPSIS... HIGH PRESSURE MOVES EAST THROUGH THE MARITIMES TODAY WHILE LOW PRESSURE APPROACHES FROM THE WEST. THIS WILL BRING TWO PERIODS OF APPRECIABLE RAINFALL TO THE AREA TODAY AND TONIGHT. THE LOW WILL EXIT THE REGION SATURDAY BUT LOW CLOUDS AND SPOTTY DRIZZLE WILL LINGER. ANOTHER LOW WILL APPROACH FROM THE SOUTH SUNDAY NIGHT AND MONDAY...BRINGING MORE RAIN TO THE AREA. YET ANOTHER WEAK LOW MAY SCRAPE BY TO THE SOUTH DURING TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1015 AM UPDATE... AREA OF RAIN MOVING ACROSS MOST OF THE REGION AT 15Z. LIGHT E-NE WINDS CONTINUE. NOTING SOME SPOTTY HIGHER REFLECTIVITIES ON NE 88D REGIONAL MOSAIC RADAR...SO WILL SEE SOME LOCALIZED BRIEF DOWNPOURS INTO THIS AFTERNOON. UPDATED WINDS TO HAVE A MORE NORTHERLY COMPONENT BASED ON LATEST OBSERVATIONS AND HRRR MODEL. TEMPS...DEW POINTS AND POPS LOOK ON TRACK. PREVIOUS DISCUSSION... SOUTHEAST LOW LEVEL JET LIFTS ACROSS SOUTHERN NEW ENGLAND TODAY...SUPPORTING ISENTROPIC LIFT OVER SOUTHERN NEW ENGLAND MUCH OF THE DAY. THE AREAS OF STRONGEST LIFT AND STRONGEST FRONTOGENETIC FORCING ARE BROUGHT ACROSS CT AND INTERIOR MASS AND SOUTHERN NH. PRECIPITABLE WATER VALUES CONTINUE TO BE ADVERTISED AT 1.5 INCHES. THE FORECAST RUNS WITH CATEGORICAL POPS FOR RAIN AND QPF VALUES OF 0.5 TO 1.0 INCHES. CLOUDS/PCPN AND LOW LEVEL EAST FLOW SHOULD KEEP TEMPS FROM CLIMBING TOO FAR TODAY. WE USED A BLEND OF MOS WHICH YIELDS MAX TEMPS IN THE MID 50S TO MID 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... TONIGHT... ONE AREA OF ISENTROPIC FORCING MOVES OFF THROUGH NORTHERN NEW ENGLAND THIS EVENING. MEANWHILE THE MAIN SURFACE LOW TURNS THE CORNER AT THE COAST AND MOVES NORTHEAST TOWARD COASTAL NEW ENGLAND. THIS BRINGS A SECOND AREA OF FRONTOGENETIC FORCING UP ACROSS THE COASTAL PLAIN DURING TONIGHT. STABILITY VALUES DIMINISH AS THE LOW APPROACHES...WITH LI VALUES SUB ZERO MAINLY OVER RI AND EASTERN MASS. WE HAVE MAINTAINED A CHANCE OF THUNDER IN THESE AREAS DURING THE NIGHT. EVEN WITH THE BREAK BETWEEN AREAS OF FORCING...THE MOIST EAST FLOW SHOULD SUPPORT CLOUDS/FOG AND POSSIBLY SOME DRIZZLE. SATURDAY... LOW PRESSURE WAVE MOVES OFF TO THE NORTHEAST BY SATURDAY AFTERNOON. EXPECT CONTINUED RAIN IN THE MORNING BUT DIMINISHING AS THE LOW MOVES OFF. NOT SURE ABOUT SUBSTANTIAL DRYING OF THE AIRMASS...SO WILL MAINTAIN MOSTLY CLOUDY SKIES THROUGH THE DAY. TEMPS ARE A BLEND OF MOS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE MODEL SOLUTIONS GIVE GOOD RESULTS ON THE OVERALL UPPER LEVEL PATTERN...ESPECIALLY WITH THE MOVEMENT OF THE H5 CLOSED LOW OUT OF THE GREAT LAKES INTO NORTHERN NEW ENGLAND THROUGH THIS WEEKEND INTO EARLY NEXT WEEK. HOWEVER...MODELS STILL HAVING DIFFICULTIES WITH THE SURFACE FEATURES...THOUGH STILL SIGNALING UNSETTLED WEATHER INTO MONDAY. NOW THOUGH...SEVERAL MEMBERS INCLUDING THE ECMWF AND GGEM STARTING TO SIGNAL YET ANOTHER LOW TRYING TO RIDE OUT OF THE GULF COAST ACROSS THE REGION TUESDAY ON THE CONTINUED SW UPPER FLOW. NOTED THAT THE 00Z OP GFS RUN BECOMING AN OUTLIER BEYOND MONDAY WITH THIS LOW. LEANED TOWARD A GFS/EC/EC ENSEMBLE BLEND EARLY...THEN MORE TOWARD THE EC LATER IN THE PACKAGE. DETAILS... SATURDAY NIGHT-SUNDAY... STALLED FRONT MEANDERS ACROSS THE REGION WHILE A WEAK WAVE APPROACHES LATE SAT NIGHT/SUN. WENT ALONG WITH LOW LIKELY POPS ACROSS RI/SE MA WHERE BEST LIFT/LL MOISTURE ARE. WITH FAIRLY GOOD E-NE FLOW IN PLACE...HAVE MENTIONED PATCHY DRIZZLE FOR SAT NIGHT/EARLY SUN AS WELL. BEST PW/S REMAIN CLOSE TO CAPE COD AND OFFSHORE...AROUND 1.5 INCHES...BUT COULD STILL SEE A COUPLE OF BRIEF HEAVY DOWNPOURS ACROSS EASTERN AREAS WHEN BEST LIFT MOVES THROUGH. WINDS VEER AROUND TO S DURING SUNDAY...SO COULD SEE TEMPS RISE TO THE 60S...MAYBE TOUCHING 70 ACROSS THE CT VALLEY AWAY FROM BEST LIFT/LL MOISTURE FEED. SUNDAY NIGHT-MONDAY... GFS STARTS TO LINGER AWAY FROM MOST OTHER SOLUTIONS AS IT TRIES TO OPEN UP THE H5 CUTOFF FASTER THAN THE GGEM/ECWMF SOLUTIONS. STILL NOTING MAINLY A S-SW UPPER FLOW CONTINUING...ALONG WITH STALLED FRONT WAVERING CLOSE TO OR JUST S OF THE REGION. BOTH GGEM AND EC INDICATING ANOTHER WEAK WAVE MOVING ACROSS EASTERN AREAS LATE SUN NIGHT/MONDAY MORNING WITH ANOTHER ROUND OF SHOWERS AND PATCHY DRIZZLE/FOG. MAY START TO SEE CONDITIONS DRY OUT SOMEWHAT OVER W MA/N CENTRAL CT/SW NH DURING THE AFTERNOON. DAYTIME HIGHS MAY BE A FEW DEGS HIGHER THAN SATURDAY...POSSIBLY INTO THE LOWER 70S IN SOME SPOTS AS WINDS SHIFT TO S-SW AND PICK UP A BIT. MONDAY NIGHT AND TUESDAY... GGEM/ECWMF MODELS IN PRETTY GOOD AGREEMENT IN BRINGING YET ANOTHER WAVE ON FRONT...WHICH WILL REMAIN JUST S OF THE REGION. BIG QUESTION AT THIS POINT WILL BE HOW FAR N WILL THIS LOW TRACK OUT OF THE GULF COAST STATES. EC TRIES TO BRING LOW ACROSS CAPE COD DURING TUESDAY SO HAVE ADDED LOW CHANCE POPS FOR THE S COAST. LOW TO MODERATE CONFIDENCE ON THIS FEATURE AT THIS TIME...HOWEVER. TUESDAY NIGHT THROUGH THURSDAY... TIMING ISSUES ABOUND DURING THIS TIMEFRAME...AND EVEN HOW THE NORTHERN STREAM INTERACTS WITH SOUTHERN STREAM ENERGY. AT THIS POINT...HAVE KEPT SLIGHT CHANCE POPS GOING THROUGH AT LEAST WEDNESDAY AS EC AND GGEM TRY TO KEEP MOISTURE PLUME ACROSS MAINLY S COASTAL AREAS BUT UNCERTAIN IF THIS WILL SET UP AS WELL AS HOW FAR N. MAY DRY THINGS OUT ACROSS N MA/S NH DURING THURSDAY. RATHER LOW CONFIDENCE ON THIS PORTION OF THE FORECAST. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT SHORT TERM... TODAY...MODERATE CONFIDENCE. RAIN WILL CONTINUE TO CROSS THE REGION. NOTING A MIX OF CIG CONDITIONS AT 15Z...BUT ANTICIPATE PRIIMARILY VFR TODAY SE COAST...AND PERIODS OF MVFR CIGS/VSBYS ACROSS MUCH OF MA/N CT WITH LOCALIZED IFR ESPECIALLY OVER THE HILLS OF WESTERN MA/N CT. VSBYS WILL LOWER TO 3-4 MILES AND MAY DIP TO 1 1/2 MILES IN SPOTS. INCREASING NE-E WINDS WITH GUSTS AROUND 20 KNOTS DURING THE LATE AFTERNOON AND EVENING ESPECIALLY IN THE COASTAL PLAIN. TONIGHT...MODERATE TO HIGH CONFIDENCE. ONE BATCH OF RAIN MOVES OFF...A SECOND MOVES UP FROM THE SOUTH. EITHER WAY...EXPECTING CIGS TO REMAIN MVFR WITH AREAS OF IFR IN RAIN AND FOG. VSBYS ALSO MVFR WITH AREAS OF IFR IN HEAVIER RAIN AREAS. SOME POTENTIAL FOR TSTMS TO DEVELOP...MAINLY ALONG THE SOUTH COAST AND THE COASTAL PLAIN. SATURDAY...MODERATE CONFIDENCE. COASTAL LOW PRESSURE PASSES AND MOVES OFF THROUGH THE GULF OF MAINE. DIMINISHING COVERAGE OF RAIN. VSBYS IMPROVE ESPECIALLY IN THE AFTERNOON. CEILINGS MAY IMPROVE...BUT LESS CERTAIN. POTENTIAL FOR LINGERING MVFR CIGS IN EASTERN MASS DURING THE AFTERNOON. KBOS TAF...MODERATE CONFIDENCE. CIGS/VSBYS REMAIN VFR THROUGH EARLY AFTERNOON...THEN LOWERING TO MVFR AFTER 20Z. COULD BE A PERIOD OF IFR VSBYS IN HEAVIER RAIN LATE AFTERNOON AND THEN A SECOND PERIOD OVERNIGHT. EAST WINDS TODAY AND AT LEAST THE START OF TONIGHT...GUSTS TO 20 KNOTS POSSIBLE. POTENTIAL FOR THUNDER TONIGHT AND EARLY SATURDAY AS COASTAL LOW PRESSURE MOVES PAST. KBDL TAF...MODERATE CONFIDENCE. MIX OF IFR TO VFR CIGS IN -RA TO START...THEN ANTICIPATE PRIMARILY MVFR CIGS. VSBYS LOWERING TO MVFR BY AFTERNOON. LOWER VSBYS IN HEAVIER RAIN ARE POSSIBLE TOWARD MIDDAY AND THIS AFTERNOON. THIS FIRST BATCH OF RAIN MOVES OFF DURING THE AFTERNOON...THEN A SECOND AREA OF RAIN MOVES UP THE COAST TONIGHT. CEILINGS SHOULD HOLD AROUND 1000-1500 FEET THROUGH THE PERIOD. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT-SUNDAY...MODERATE CONFIDENCE. MAINLY MVFR/VFR CIGS. SCT SHOWERS/PATCHY DRZL AND FOG ACROSS MOST OF THE REGION...WITH BEST CHANCE ACROSS RI/E MA LATE SAT NIGHT/SUN. LOW-MODERATE PROB OF IFR CIGS/VSBYS LATE SAT NIGHT IN FOG/DRZL PATCHES. SUNDAY NIGHT-MONDAY...MODERATE CONFIDENCE. EXPECT MVFR-VFR CIGS/VSBYS IN SCT SHOWERS/PATCHY DRZL/FOG. ANOTHER LOW MOVES ALONG PASSING FRONT LATE SUN NIGHT/MON MORNING WITH SHOWERS LIKELY ACROSS RI/E MA. LOCAL IFR VSBYS POSSIBLE IN ANY BRIEF HEAVY DOWNPOURS. SW WINDS MAY GUST TO UP TO 20 KT ON THE S COAST DURING MON. MONDAY NIGHT INTO TUESDAY...MODERATE CONFIDENCE. SHOULD BE MAINLY VFR MON NIGHT WITH PATCHY MVFR-IFR VSBYS IN PATCHY FOG. YET ANOTHER LOW MOVES S OF THE REGION...WHICH MAY BRING SCT SHOWERS ACROSS RI/SE MA WITH LOCAL MVFR CIGS/VSBYS. && .MARINE... TODAY... INCREASING SOUTHEAST WINDS AS LOW PRESSURE ROLLS ACROSS FROM THE OHIO VALLEY. WINDS JUST OFF THE SURFACE WILL REACH 20-25 KNOTS...WITH CONFIDENCE THAT SOME OR ALL OF THIS WILL REACH THE SURFACE THIS AFTERNOON...ESPECIALLY IN ANY RAIN. THE WIND WILL SERVE TO BUILD SEAS WITH 5 FOOT VALUES ON THE OUTER WATERS. SMALL CRAFT ADVISORY CONTINUES...FOR THE SOUTHERN WATERS THIS MORNING AND FOR MOST WATERS THIS AFTERNOON. TONIGHT... AS THE CENTER OF LOW PRESSURE MOVES UP OVER THE WATERS...THE DIMINISHING PRESSURE GRADIENT WILL ALLOW WINDS TO DIMINISH AS WELL. SMALL CRAFT ADVISORY CONTINUES...WITH SMALL ADJUSTMENTS TO ENDING TIMES AS THE WINDS AND SEAS DIMINISH OVERNIGHT. SATURDAY... WINDS AND SEAS DIMINISH WITH VALUES EXPECTED TO REMAIN BELOW SMALL CRAFT THRESHOLDS. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT THROUGH SUNDAY NIGHT...MODERATE CONFIDENCE. WINDS EXPECTED TO REMAIN BELOW 15 KT...MAINLY FROM THE E-NE THOUGH WILL BE SHIFTING AS LOW PRES MOVES ACROSS THE EASTERN WATERS SUNDAY NIGHT. SEAS WILL ALSO REMAIN BELOW SMALL CRAFT CRITERIA. VSBY RESTRICTIONS IN SCATTERED SHOWERS ALONG WITH PATCHY RAIN AND NIGHTTIME DRIZZLE. MONDAY AND TUESDAY...MODERATE CONFIDENCE. SW WINDS PICK UP ON MONDAY...GUSTS UP TO 20 KT. SEAS MAY BUILD TO 5 FT ON THE SOUTHERN OUTER WATERS. WINDS DIMINISH MON NIGHT INTO TUESDAY. ANOTHER LOW WILL SCRAPE ACROSS THE SOUTHERN WATERS TUE...WITH SOME VSBY RESTRICTIONS IN SCT SHOWERS/PATCHY FOG. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ232>234. SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR ANZ231. SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR ANZ235-237- 255-256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ250-251- 254. && $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB/EVT/NMB SHORT TERM...WTB LONG TERM...EVT AVIATION...WTB/EVT/NMB MARINE...WTB/EVT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
156 AM EDT FRI SEP 28 2012 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT. LOW PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT AND WILL CROSS THE REGION THIS AFTERNOON AND NIGHT. THE LOW WILL THEN MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD AFFECT THE REGION AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... JUST MADE SOME MINOR ADJUSTMENTS TO TEMPS TO MATCH CURRENT TRENDS...OTHERWISE REST OF FORECAST IS ON TRACK. A WAVE OF LOW PRESSURE ALONG A STATIONARY FRONT TO THE SOUTH OF THE REGION IS APPROACHING. THIS WILL BRING THE MOST SYNOPTIC FORCING AFTER 6Z AS NOTED FROM 850-500MB Q VECTOR CONVERGENCE WITH THE APPROACHING SHORTWAVE AND ATTENDANT INCREASE IN LAYER PW VALUES TO AROUND 1.5 INCHES. IN ADDITION...PRETTY DECENT ISENTROPIC LIFT HAS BEEN NOTED IN THE MODEL FIELDS ALONG THE 300 K ISENTROPE STARTING AT 6Z AND CONTINUING INTO EARLY FRIDAY MORNING. LATEST HRRR MODEL REFLECTIVITY FIELDS SUGGEST RAIN SPREADS ACROSS THE REMAINDER OF THE AREA GRADUALLY EARLY THIS MORNING. THIS SEEMS TO FIT WITH LINEAR EXTRAPOLATIONS OF CURRENT RADAR REFLECTIVITY. WILL MAINTAIN HEAVY RAIN MENTION. ALSO...THERE IS AGREEMENT WITH THE MODELS OF MUCAPE OF A FEW HUNDRED J/KG SO MENTIONED ISOLATED THUNDERSTORMS AS WELL...BUT RESTRICTED THIS TOWARDS SOUTHWESTERN COASTAL PORTIONS OF THE FORECAST REGION. MIN TEMPS WERE SLIGHTLY INCREASED TOWARDS THE NORTHERN HALF OF THE FORECAST AREA BUT OVERALL...NO SIGNIFICANT CHANGES WERE MADE TO THESE AND THE DEWPOINTS FIELDS. STILL LOOKING AT A GENERAL RANGE OF MIN TEMPS FROM THE LOWER/MID 50S TO THE LOWER 60S WHICH IS CONSISTENT WITH A MAV/MET BLEND. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF RAIN THROUGH MIDDAY FRI. AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY TSTMS ARE POSSIBLE. THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP DURING THAT TIME. THERE IS A HIGH RISK OF RIP CURRENTS AT THE OCEAN BEACHES WEDNESDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES NORTH AND WEST OF THE NEW YORK METRO AREA. A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY. THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS DUE TO UNCERTAINTY. HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... A FRONTAL BOUNDARY SOUTH OF THE REGION WILL SLOWLY LIFT NORTH TOWARDS THE REGION TODAY. A WAVE OF LOW PRESSURE...ON THE FRONT...APPROACHES FROM THE WEST EARLY THIS MORNING...AND MOVES THROUGH DURING THE DAY TODAY. FORECAST CONFIDENCE IS LOW. THE FORECAST...ESPECIALLY WINDS...WILL DEPEND ON THE TRACK OF THE LOW AND ASSOCIATED WARM FRONT. THERE REMAINS UNCERTAINTY IN THE FORECAST AS TO WHETHER OR NOT THE WARM FRONT MOVES ON SHORE FRIDAY MORNING...AND IF IT DOES HOW FAR NORTH THE WARM FRONT WILL MOVE. THERE IS ALSO A CHANCE THAT WINDS COULD GUST FOR A PERIOD THIS MORNING. DEPENDING ON HOW FAR NORTH THE FRONT LIFTS...WILL ALSO DEPENDS ON THE TRACK OF THE LOW. CIGS WILL GRADUALLY LOWER TO 1500 TO 2500 FT. MEANWHILE...VISIBILITIES WILL LOWER TO 3 TO 5 SM IN DEVELOPING SHOWERS AND FOG...AND THEN LOWER TO AROUND 2 SM IN RAIN AND FOG TOWARD 12Z OR SO. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS FRIDAY MORNING...AROUND 12Z TO 18Z. NOT INCLUDED AT THIS TIME WITH THE LOW PROBABILITY AND ISOLATED COVERAGE. OUTLOOK FOR 06Z SAT-TUE... .FRI NIGHT...MVFR CEILINGS AND VISIBILITIES IN SHOWERS. CONDITIONS IMPROVING TOWARD SAT MORNING. LOW CONFIDENCE. .SAT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS. && .MARINE... FAIRLY TRANQUIL CONDITIONS WILL QUICKLY DETERIORATE EARLY THIS MORNING AS WINDS INCREASE...BUILDING SEAS. SCA REMAIN IN EFFECT FOR ALL WATERS. EASTERLY FLOW LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT...ABOUT 1 FT ABOVE 12Z WAVEWATCH. SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED. && .HYDROLOGY... UP TO 2 INCHES OF RAINFALL POSSIBLE THROUGH TONIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER INITIALLY THIS MORNING... FROM NYC METRO AND POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC HAS BEEN POSTED TO THE WEB. && .TIDES/COASTAL FLOODING... COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING THIS MORNING COULD LEAD TO ISOLATED MINOR COASTAL FLOODING AT THE TIMES OF HIGH TIDE TONIGHT IN THE MOST VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG ISLAND...AND ALONG WRN LONG ISLAND SOUND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO NOON EDT TODAY FOR ANZ335-338-345. SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ330-340. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350- 353-355. && $$ SYNOPSIS... NEAR TERM...GOODMAN/JM/PW SHORT TERM...GOODMAN LONG TERM... AVIATION...BC MARINE...GOODMAN/PW HYDROLOGY...GOODMAN TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
105 AM EDT FRI SEP 28 2012 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT. LOW PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT AND WILL CROSS THE REGION THIS AFTERNOON AND NIGHT. THE LOW WILL THEN MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD AFFECT THE REGION AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... JUST MADE SOME MINOR ADJUSTMENTS TO TEMPS TO MATCH CURRENT TRENDS...OTHERWISE REST OF FORECAST IS ON TRACK. A WAVE OF LOW PRESSURE ALONG A STATIONARY FRONT TO THE SOUTH OF THE REGION IS APPROACHING. THIS WILL BRING THE MOST SYNOPTIC FORCING AFTER 6Z AS NOTED FROM 850-500MB Q VECTOR CONVERGENCE WITH THE APPROACHING SHORTWAVE AND ATTENDANT INCREASE IN LAYER PW VALUES TO AROUND 1.5 INCHES. IN ADDITION...PRETTY DECENT ISENTROPIC LIFT HAS BEEN NOTED IN THE MODEL FIELDS ALONG THE 300 K ISENTROPE STARTING AT 6Z AND CONTINUING INTO EARLY FRIDAY MORNING. LATEST HRRR MODEL REFLECTIVITY FIELDS SUGGEST RAIN SPREADS ACROSS THE REMAINDER OF THE AREA GRADUALLY EARLY THIS MORNING. THIS SEEMS TO FIT WITH LINEAR EXTRAPOLATIONS OF CURRENT RADAR REFLECTIVITY. WILL MAINTAIN HEAVY RAIN MENTION. ALSO...THERE IS AGREEMENT WITH THE MODELS OF MUCAPE OF A FEW HUNDRED J/KG SO MENTIONED ISOLATED THUNDERSTORMS AS WELL...BUT RESTRICTED THIS TOWARDS SOUTHWESTERN COASTAL PORTIONS OF THE FORECAST REGION. MIN TEMPS WERE SLIGHTLY INCREASED TOWARDS THE NORTHERN HALF OF THE FORECAST AREA BUT OVERALL...NO SIGNIFICANT CHANGES WERE MADE TO THESE AND THE DEWPOINTS FIELDS. STILL LOOKING AT A GENERAL RANGE OF MIN TEMPS FROM THE LOWER/MID 50S TO THE LOWER 60S WHICH IS CONSISTENT WITH A MAV/MET BLEND. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF RAIN THROUGH MIDDAY FRI. AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY TSTMS ARE POSSIBLE. THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP DURING THAT TIME. THERE IS A HIGH RISK OF RIP CURRENTS AT THE OCEAN BEACHES WEDNESDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES NORTH AND WEST OF THE NEW YORK METRO AREA. A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY. THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS DUE TO UNCERTAINTY. HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... A COLD FRONT WILL REMAIN JUST TO THE SOUTH TONIGHT. A WAVE OF LOW PRESSURE...ON THE FRONT...APPROACHES FROM THE WEST OVERNIGHT...AND MOVES THROUGH DURING THE FORECAST PERIOD. FORECAST...ESPECIALLY WINDS AND GUSTS...WILL DEPEND ON THE TRACK OF THE LOW AND ASSOCIATED WARM FRONT. THERE IS UNCERTAINTY IF THE WARM FRONT MOVES ON SHORE FRIDAY MORNING...AND IF IT DOES HOW FAR NORTH THE WARM FRONT WILL MOVE. FORECAST CONFIDENCE IS LOW. VFR CONDITIONS LOWER WITH 1500 TO 2500 FT CEILINGS DEVELOPING. VISIBILITIES WILL LOWER TO 3 TO 5 SM IN DEVELOPING SHOWERS AND FOG...AND THEN LOWER TO AROUND 2 SM IN RAIN AND FOG TOWARD FRIDAY MORNING. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS FRIDAY MORNING...AROUND 12Z TO 18Z. NOT INCLUDED AT THIS TIME WITH THE LOW PROBABILITY AND ISOLATED COVERAGE. OUTLOOK FOR 00Z SAT-TUE... .FRI NIGHT...MVFR CEILINGS AND VISIBILITIES IN SHOWERS. CONDITIONS IMPROVING TOWARD SAT MORNING. LOW CONFIDENCE. .SAT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS. && .MARINE... FAIRLY TRANQUIL CONDITIONS WILL QUICKLY DETERIORATE EARLY THIS MORNING AS WINDS INCREASE...BUILDING SEAS. SCA REMAIN IN EFFECT FOR ALL WATERS. EASTERLY FLOW LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT...ABOUT 1 FT ABOVE 12Z WAVEWATCH. SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED. && .HYDROLOGY... UP TO 2 INCHES OF RAINFALL POSSIBLE THROUGH TONIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER INITIALLY THIS MORNING... FROM NYC METRO AND POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC HAS BEEN POSTED TO THE WEB. && .TIDES/COASTAL FLOODING... COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING THIS MORNING COULD LEAD TO ISOLATED MINOR COASTAL FLOODING AT THE TIMES OF HIGH TIDE TONIGHT IN THE MOST VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG ISLAND...AND ALONG WRN LONG ISLAND SOUND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO NOON EDT TODAY FOR ANZ335-338-345. SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ330-340. SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ350-353-355. && $$ SYNOPSIS... NEAR TERM...GOODMAN/JM/PW SHORT TERM...GOODMAN LONG TERM... AVIATION...MET MARINE...GOODMAN/PW HYDROLOGY...GOODMAN TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
105 PM EDT FRI SEP 28 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 1106 AM EDT FRI SEP 28 2012 LOW STRATUS SLOWLY MOVING OUT OF THE FORECAST AREA LATE THIS MORNING...WITH CLOUD COVER AND FOG LARGELY CONFINED TO THE EASTERN HALF OF THE FORECAST AREA. STILL A FEW LIGHT SHOWERS OVER FAR SOUTHERN COUNTIES AS WELL. TEMPS AT 15Z WERE IN THE UPPER 50S AND LOWER 60S. MODEL SOUNDINGS AND RH PROGS SHOW LOWER CLOUDS AND FOG WILL CONTINUE TO MOVE EAST AND MIX OUT INTO A CU FIELD INTO THE AFTERNOON AS DRIER AIR FILTERS INTO CENTRAL INDIANA. IN LOCATIONS ACROSS THE WABASH VALLEY WHERE SKIES HAVE CLEARED...SHOULD SEE CU REDEVELOP AS CONVECTIVE TEMPS ARE MET BY EARLY AFTERNOON. HELD ONTO A 20 POP OVER EXTREME SOUTHERN PORTIONS OF THE FORECAST AREA TO ACCOUNT FOR ONGOING LIGHT SHOWERS. HRRR INDICATING THAT THE PRECIP SHOULD BE OUT OF SOUTHERN COUNTIES BY 18Z WITH DRY WEATHER THEREAFTER. WITH A SLOWER DEPARTURE TO CLOUDS THIS MORNING...LOWERED HIGH TEMPS A DEGREE OR TWO IN MOST LOCATIONS. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 28/18Z TAFS/... ISSUED AT 105 PM EDT FRI SEP 28 2012 BECOMING VFR QUICKLY AT ALL SITES THAT HAVE NOT YET DONE SO...MAINLY JUST IND. ADDITIONAL RESTRICTIONS POSSIBLE NEAR SUNRISE SATURDAY. LOW CEILINGS AND FOG HAVE BEEN SLOW TO BURN OFF THIS MORNING AT SOME SITES...BUT ARE WELL ON THEIR WAY NOW. SCT TO BKN030-040 SHOULD BE THE RULE FOR MUCH OF THE AFTERNOON...WITH THIS LOWER CLOUD DISSIPATING AT SUNSET. SOME LOW LEVEL MOISTURE WILL REMAIN IN PLACE TONIGHT...AND EXPERIMENTAL SATELLITE GUIDANCE SUGGESTS IFR CONDITIONS POSSIBLE AGAIN IN THE SOUTH. WILL CARRY MVFR RESTRICTIONS IN FOG WITH A SCT015 MENTION LATE TONIGHT AT IND/LAF/HUF...AND IFR AT BMG. THIS SHOULD BURN OFF IN TYPICAL DIURNAL FASHION MID MORNING TOMORROW. WINDS WILL REMAIN BELOW 10KT THROUGHOUT THE PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....MK AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1106 AM EDT FRI SEP 28 2012 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 1106 AM EDT FRI SEP 28 2012 LOW STRATUS SLOWLY MOVING OUT OF THE FORECAST AREA LATE THIS MORNING...WITH CLOUD COVER AND FOG LARGELY CONFINED TO THE EASTERN HALF OF THE FORECAST AREA. STILL A FEW LIGHT SHOWERS OVER FAR SOUTHERN COUNTIES AS WELL. TEMPS AT 15Z WERE IN THE UPPER 50S AND LOWER 60S. MODEL SOUNDINGS AND RH PROGS SHOW LOWER CLOUDS AND FOG WILL CONTINUE TO MOVE EAST AND MIX OUT INTO A CU FIELD INTO THE AFTERNOON AS DRIER AIR FILTERS INTO CENTRAL INDIANA. IN LOCATIONS ACROSS THE WABASH VALLEY WHERE SKIES HAVE CLEARED...SHOULD SEE CU REDEVELOP AS CONVECTIVE TEMPS ARE MET BY EARLY AFTERNOON. HELD ONTO A 20 POP OVER EXTREME SOUTHERN PORTIONS OF THE FORECAST AREA TO ACCOUNT FOR ONGOING LIGHT SHOWERS. HRRR INDICATING THAT THE PRECIP SHOULD BE OUT OF SOUTHERN COUNTIES BY 18Z WITH DRY WEATHER THEREAFTER. WITH A SLOWER DEPARTURE TO CLOUDS THIS MORNING...LOWERED HIGH TEMPS A DEGREE OR TWO IN MOST LOCATIONS. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 28/15Z TAF UPDATE/... ISSUED AT 1012 AM EDT FRI SEP 28 2012 CLEARING TO THE WEST IS TRYING TO MAKE ITS WAY INTO IND AND BMG...AND LIKELY WILL IN THE NEXT FEW HOURS. MINOR ADJUSTMENTS REQUIRED. ISSUED AT 618 AM EDT FRI SEP 28 2012 HIGH PRESSURE AND RESIDUAL LOW LEVEL MOISTURE WAS ALLOWING FOG AND STRATUS TO FORM MAINLY AT IND AND BMG OVERNIGHT. OBSERVATIONAL TRENDS...MESOSCALE MODELS INCLUDING THE NORTH AMERICAN RAPID REFRESH ENSEMBLE SYSTEM ALL FAVOR LIFR OR WORSE CONDITIONS AT BMG TO GRADUALLY IMPROVE TO IFR TOWARD 14Z AND MVFR AND BETTER SHORTLY THEREAFTER. IND ALSO WAS SEEING LOW CEILINGS AND SHORT START OFF AT IFR OR WORSE BEFORE BECOMING MVFR BY 14Z AND VFR BY 16Z. CU DEVELOPMENT PROGS WERE INDICATING AT LEAST BROKEN DIURNAL CU. THE OTHER SITES WERE DOING BETTER WITH LESS LOW LEVEL MOISTURE SHOWING UP NICE IN THE MODELS AND THE RAPID REFRESH. COULD ONCE AGAIN SEE SOME FOG AT BMG TONIGHT...BUT WILL ONLY GO AS LOW AS IFR THERE FOR NOW AFTER 04Z. OTHERWISE...DRIER AIR SETTLING DOWN FROM THE NORTH SHOULD KEEP FOG LIGHT IF AT ALL. WINDS THROUGH THE PERIOD WILL SEE A NORTHERLY COMPONENT AND LESS THAN 10 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...RYAN SHORT TERM...CP LONG TERM....MK AVIATION...MK/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1012 AM EDT FRI SEP 28 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /TODAY/... ISSUED AT 359 AM EDT FRI SEP 28 2012 MAIN CONCERN IS WHETHER OR NOT TO INCLUDE POPS IN THE SOUTH FOR A FEW HOURS THIS MORNING. NAM/GFS/ECMWF ARE ALL SHOWING VERY SMALL QPF ACROSS THE SOUTHERNMOST COUNTIES THIS MORNING...AND HRRR SHOWS DEVELOPMENT OF SOME ECHOES ACROSS THE SOUTHERN AND CENTRAL COUNTIES. THIS IS ASSOCIATED WITH A MID LEVEL SHORTWAVE MOVING THROUGH THE FLOW. TIME HEIGHTS SHOW A LOT OF DRY AIR IN THE MID LEVELS THOUGH MAKING SATURATION THROUGH THE COLUMN DIFFICULT AND DRY ADVECTION IS OCCURRING ACROSS AT LEAST THE CENTRAL AND NORTHERN COUNTIES CURRENTLY. WATER VAPOR LOOP SHOWS THE SHORTWAVE CURRENTLY ACROSS MISSOURI AND SOME SHOWERS FIRING UP IN FRONT OF IT. ULTIMATELY THINK THE SHOWERS WILL HAVE TO OVERCOME THE DRY AIR AS THEY HEAD EAST SO MAY WIND UP JUST BEING SPRINKLES BY THE TIME THEY REACH INDIANA...BUT COULD ALSO SEE A HUNDREDTH OR TWO EEK OUT IN THE FAR SOUTHERN COUNTIES. THUS WILL GO WITH AROUND A 30 POP IN THE SOUTH...TIMED OUT TO MATCH WITH THE CURRENT MOVEMENT OF THE RAIN SHIELD IN WESTERN ILLINOIS. DON/T SEE INSTABILITY GETTING THIS FAR NORTH SO WILL NOT INCLUDE THUNDER MENTION. BY AFTERNOON ENTIRE AREA SHOULD BE DRY. CU RULE SHOWS SCATTERED TO BROKEN CLOUD COVER DECREASING BY EVENING AND 850 MB TEMPERATURES DECREASING BUT NOT UNTIL LATER IN THE DAY. THUS THINK HIGHS WILL BE NEAR YESTERDAY...PERHAPS A DEGREE OR SO COOLER AND THE MAV NUMBERS WENT WELL WITH THIS THEORY. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 28/15Z TAF UPDATE/... ISSUED AT 1012 AM EDT FRI SEP 28 2012 CLEARING TO THE WEST IS TRYING TO MAKE ITS WAY INTO IND AND BMG...AND LIKELY WILL IN THE NEXT FEW HOURS. MINOR ADJUSTMENTS REQUIRED. ISSUED AT 618 AM EDT FRI SEP 28 2012 HIGH PRESSURE AND RESIDUAL LOW LEVEL MOISTURE WAS ALLOWING FOG AND STRATUS TO FORM MAINLY AT IND AND BMG OVERNIGHT. OBSERVATIONAL TRENDS...MESOSCALE MODELS INCLUDING THE NORTH AMERICAN RAPID REFRESH ENSEMBLE SYSTEM ALL FAVOR LIFR OR WORSE CONDITIONS AT BMG TO GRADUALLY IMPROVE TO IFR TOWARD 14Z AND MVFR AND BETTER SHORTLY THEREAFTER. IND ALSO WAS SEEING LOW CEILINGS AND SHORT START OFF AT IFR OR WORSE BEFORE BECOMING MVFR BY 14Z AND VFR BY 16Z. CU DEVELOPMENT PROGS WERE INDICATING AT LEAST BROKEN DIURNAL CU. THE OTHER SITES WERE DOING BETTER WITH LESS LOW LEVEL MOISTURE SHOWING UP NICE IN THE MODELS AND THE RAPID REFRESH. COULD ONCE AGAIN SEE SOME FOG AT BMG TONIGHT...BUT WILL ONLY GO AS LOW AS IFR THERE FOR NOW AFTER 04Z. OTHERWISE...DRIER AIR SETTLING DOWN FROM THE NORTH SHOULD KEEP FOG LIGHT IF AT ALL. WINDS THROUGH THE PERIOD WILL SEE A NORTHERLY COMPONENT AND LESS THAN 10 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....MK AVIATION...MK/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
618 AM EDT FRI SEP 28 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /TODAY/... ISSUED AT 359 AM EDT FRI SEP 28 2012 MAIN CONCERN IS WHETHER OR NOT TO INCLUDE POPS IN THE SOUTH FOR A FEW HOURS THIS MORNING. NAM/GFS/ECMWF ARE ALL SHOWING VERY SMALL QPF ACROSS THE SOUTHERNMOST COUNTIES THIS MORNING...AND HRRR SHOWS DEVELOPMENT OF SOME ECHOES ACROSS THE SOUTHERN AND CENTRAL COUNTIES. THIS IS ASSOCIATED WITH A MID LEVEL SHORTWAVE MOVING THROUGH THE FLOW. TIME HEIGHTS SHOW A LOT OF DRY AIR IN THE MID LEVELS THOUGH MAKING SATURATION THROUGH THE COLUMN DIFFICULT AND DRY ADVECTION IS OCCURRING ACROSS AT LEAST THE CENTRAL AND NORTHERN COUNTIES CURRENTLY. WATER VAPOR LOOP SHOWS THE SHORTWAVE CURRENTLY ACROSS MISSOURI AND SOME SHOWERS FIRING UP IN FRONT OF IT. ULTIMATELY THINK THE SHOWERS WILL HAVE TO OVERCOME THE DRY AIR AS THEY HEAD EAST SO MAY WIND UP JUST BEING SPRINKLES BY THE TIME THEY REACH INDIANA...BUT COULD ALSO SEE A HUNDREDTH OR TWO EEK OUT IN THE FAR SOUTHERN COUNTIES. THUS WILL GO WITH AROUND A 30 POP IN THE SOUTH...TIMED OUT TO MATCH WITH THE CURRENT MOVEMENT OF THE RAIN SHIELD IN WESTERN ILLINOIS. DON/T SEE INSTABILITY GETTING THIS FAR NORTH SO WILL NOT INCLUDE THUNDER MENTION. BY AFTERNOON ENTIRE AREA SHOULD BE DRY. CU RULE SHOWS SCATTERED TO BROKEN CLOUD COVER DECREASING BY EVENING AND 850 MB TEMPERATURES DECREASING BUT NOT UNTIL LATER IN THE DAY. THUS THINK HIGHS WILL BE NEAR YESTERDAY...PERHAPS A DEGREE OR SO COOLER AND THE MAV NUMBERS WENT WELL WITH THIS THEORY. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 281200Z TAF ISSUANCE/... ISSUED AT 618 AM EDT FRI SEP 28 2012 HIGH PRESSURE AND RESIDUAL LOW LEVEL MOISTURE WAS ALLOWING FOG AND STRATUS TO FORM MAINLY AT IND AND BMG OVERNIGHT. OBSERVATIONAL TRENDS...MESOSCALE MODELS INCLUDING THE NORTH AMERICAN RAPID REFRESH ENSEMBLE SYSTEM ALL FAVOR LIFR OR WORSE CONDITIONS AT BMG TO GRADUALLY IMPROVE TO IFR TOWARD 14Z AND MVFR AND BETTER SHORTLY THEREAFTER. IND ALSO WAS SEEING LOW CEILINGS AND SHORT START OFF AT IFR OR WORSE BEFORE BECOMING MVFR BY 14Z AND VFR BY 16Z. CU DEVELOPMENT PROGS WERE INDICATING AT LEAST BROKEN DIURNAL CU. THE OTHER SITES WERE DOING BETTER WITH LESS LOW LEVEL MOISTURE SHOWING UP NICE IN THE MODELS AND THE RAPID REFRESH. COULD ONCE AGAIN SEE SOME FOG AT BMG TONIGHT...BUT WILL ONLY GO AS LOW AS IFR THERE FOR NOW AFTER 04Z. OTHERWISE...DRIER AIR SETTLING DOWN FROM THE NORTH SHOULD KEEP FOG LIGHT IF AT ALL. WINDS THROUGH THE PERIOD WILL SEE A NORTHERLY COMPONENT AND LESS THAN 10 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....MK AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
426 AM EDT FRI SEP 28 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /TODAY/... ISSUED AT 359 AM EDT FRI SEP 28 2012 MAIN CONCERN IS WHETHER OR NOT TO INCLUDE POPS IN THE SOUTH FOR A FEW HOURS THIS MORNING. NAM/GFS/ECMWF ARE ALL SHOWING VERY SMALL QPF ACROSS THE SOUTHERNMOST COUNTIES THIS MORNING...AND HRRR SHOWS DEVELOPMENT OF SOME ECHOES ACROSS THE SOUTHERN AND CENTRAL COUNTIES. THIS IS ASSOCIATED WITH A MID LEVEL SHORTWAVE MOVING THROUGH THE FLOW. TIME HEIGHTS SHOW A LOT OF DRY AIR IN THE MID LEVELS THOUGH MAKING SATURATION THROUGH THE COLUMN DIFFICULT AND DRY ADVECTION IS OCCURRING ACROSS AT LEAST THE CENTRAL AND NORTHERN COUNTIES CURRENTLY. WATER VAPOR LOOP SHOWS THE SHORTWAVE CURRENTLY ACROSS MISSOURI AND SOME SHOWERS FIRING UP IN FRONT OF IT. ULTIMATELY THINK THE SHOWERS WILL HAVE TO OVERCOME THE DRY AIR AS THEY HEAD EAST SO MAY WIND UP JUST BEING SPRINKLES BY THE TIME THEY REACH INDIANA...BUT COULD ALSO SEE A HUNDREDTH OR TWO EEK OUT IN THE FAR SOUTHERN COUNTIES. THUS WILL GO WITH AROUND A 30 POP IN THE SOUTH...TIMED OUT TO MATCH WITH THE CURRENT MOVEMENT OF THE RAIN SHIELD IN WESTERN ILLINOIS. DON/T SEE INSTABILITY GETTING THIS FAR NORTH SO WILL NOT INCLUDE THUNDER MENTION. BY AFTERNOON ENTIRE AREA SHOULD BE DRY. CU RULE SHOWS SCATTERED TO BROKEN CLOUD COVER DECREASING BY EVENING AND 850 MB TEMPERATURES DECREASING BUT NOT UNTIL LATER IN THE DAY. THUS THINK HIGHS WILL BE NEAR YESTERDAY...PERHAPS A DEGREE OR SO COOLER AND THE MAV NUMBERS WENT WELL WITH THIS THEORY. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 280900Z TAF UPDATES/... ISSUED AT 426 AM EDT FRI SEP 28 2012 BMG CEILING AND VISIBILITY HAS DROPPED TO LIFR AND SHOULD REMAIN THERE OR WORSE OVERNIGHT. OTHERWISE...HUF WAS VFR WITH A 4K DECK AND STILL 8 DEGREE TEMPERATURE/DEW POINT SPREAD...SO PULLED FOG AND LOW CEILINGS THERE. OTHERWISE...LITTLE CHANGES TO THE TAFS. PREVIOUS DISCUSSION FOLLOWS... A PERIOD OF IFR CEILINGS FOG STILL LIKELY AT KIND...KHUF...KBMG... WHILE MVFR CEILINGS FOG STILL POSSIBLE AT KLAF. THIS WILL OCCUR LATE TONIGHT AND EARLY FRIDAY MAINLY FROM 09Z-14Z. SATELLITE AND WEATHER DEPICTION IS SHOWING AN AREA OF IFR CEILINGS ADVANCING ACROSS EAST CENTRAL INDIANA AND DEWPOINTS STILL AROUND 60 AT KIND...KHUF AND KBMG. WITH LIGHT WINDS AND MOIST GROUND AND SOME RADIATIONAL COOLING EXPECT IFR CONDITIONS TO GRADUALLY INCREASE LATE TONIGHT. DRIER AIR HAS SPREAD INTO KLAF...BUT WEATHER DEPICTION SHOWS SOME AREAS OF MVFR CEILINGS TO THE NORTHEAST OF KLAF. ON FRIDAY...STRATUS/FOG WILL LIFT BY MID TO LATE MORNING. CONVECTIVE TEMPERATURES WILL BE IN UPPER 60S...SO EXPECT MOSTLY BROKEN 4 TO 5 THOUSAND CLOUDS MIDDAY ON WITH CLEARING LATE FRIDAY AND EARLY FRIDAY EVENING. HIGH PRESSURE OVER THE GREAT LAKES WILL KEEP US UNDER A VERY LIGHT NORTH TO NORTHEAST FLOW FRIDAY AND FRIDAY EVENING. WINDS WILL BE ALMOST NEAR CALM OVERNIGHT AND 7 KNOTS OR LESS FRIDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....MK AVIATION...JH/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
404 AM EDT FRI SEP 28 2012 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 359 AM EDT FRI SEP 28 2012 A LARGE CANADIAN UPPER LOW WILL DIG INTO THE GREAT LAKES FOR THE WEEKEND BRINGING SLIGHTLY COOLER TEMPERATURES WITH IT. THIS FEATURE WILL MOVE OFF TO THE EAST ON MONDAY AND MORE ZONAL FLOW WILL SET UP ACROSS THE AREA WITH A SLOW WARMING TREND AND DRY WEATHER INTO MID WEEK. && .NEAR TERM /TODAY/... ISSUED AT 359 AM EDT FRI SEP 28 2012 MAIN CONCERN IS WHETHER OR NOT TO INCLUDE POPS IN THE SOUTH FOR A FEW HOURS THIS MORNING. NAM/GFS/ECMWF ARE ALL SHOWING VERY SMALL QPF ACROSS THE SOUTHERNMOST COUNTIES THIS MORNING...AND HRRR SHOWS DEVELOPMENT OF SOME ECHOES ACROSS THE SOUTHERN AND CENTRAL COUNTIES. THIS IS ASSOCIATED WITH A MID LEVEL SHORTWAVE MOVING THROUGH THE FLOW. TIME HEIGHTS SHOW A LOT OF DRY AIR IN THE MID LEVELS THOUGH MAKING SATURATION THROUGH THE COLUMN DIFFICULT AND DRY ADVECTION IS OCCURRING ACROSS AT LEAST THE CENTRAL AND NORTHERN COUNTIES CURRENTLY. WATER VAPOR LOOP SHOWS THE SHORTWAVE CURRENTLY ACROSS MISSOURI AND SOME SHOWERS FIRING UP IN FRONT OF IT. ULTIMATELY THINK THE SHOWERS WILL HAVE TO OVERCOME THE DRY AIR AS THEY HEAD EAST SO MAY WIND UP JUST BEING SPRINKLES BY THE TIME THEY REACH INDIANA...BUT COULD ALSO SEE A HUNDREDTH OR TWO EEK OUT IN THE FAR SOUTHERN COUNTIES. THUS WILL GO WITH AROUND A 30 POP IN THE SOUTH...TIMED OUT TO MATCH WITH THE CURRENT MOVEMENT OF THE RAIN SHIELD IN WESTERN ILLINOIS. DON/T SEE INSTABILITY GETTING THIS FAR NORTH SO WILL NOT INCLUDE THUNDER MENTION. BY AFTERNOON ENTIRE AREA SHOULD BE DRY. CU RULE SHOWS SCATTERED TO BROKEN CLOUD COVER DECREASING BY EVENING AND 850 MB TEMPERATURES DECREASING BUT NOT UNTIL LATER IN THE DAY. THUS THINK HIGHS WILL BE NEAR YESTERDAY...PERHAPS A DEGREE OR SO COOLER AND THE MAV NUMBERS WENT WELL WITH THIS THEORY. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 359 AM EDT FRI SEP 28 2012 FORECAST FOCUS IS ON SKY COVER AND TEMPERATURES. MODELS ARE IN PRETTY GOOD AGREEMENT SO WILL GENERALLY USE A CONSENSUS. FOR TONIGHT AND SATURDAY EXPECT TO SEE DECREASING CLOUDS ESPECIALLY IN THE WEST CLOSER TO THE SURFACE HIGH. AN UPPER TROUGH DIGGING INTO THE GREAT LAKES AND SWINGING A SHORTWAVE THROUGH POSSIBLE NORTHEASTERN INDIANA OR OHIO COULD KEEP MORE CLOUDS ACROSS NORTHEASTERN PARTS OF THE AREA SO MAINTAINED HIGHER SKY COVER HERE...BUT LACK OF ANY SIGNIFICANT MOISTURE AND THE FEATURE ITSELF POTENTIALLY BEING FURTHER EAST PRECLUDE ANY POP MENTION. GENERALLY USED A GUIDANCE CONSENSUS FOR OVERNIGHT LOWS AS GUIDANCE DID A BETTER JOB OF CAPTURING HEAT ISLAND EFFECTS EXPECTING WITH MOSTLY CLEAR SKIES FOR MOST OF THE AREA DURING THE OVERNIGHT HOURS. FOR HIGHS USED A CONSENSUS FOR SATURDAY...BUT WENT COOLER THAN GUIDANCE FOR SUNDAY WITH COLD ADVECTION AT 850 ON THE BACK SIDE OF THE UPPER LOW. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 316 AM EDT FRI SEP 28 2012 MAIN FOCUS TO THE EXTENDED WILL BE TEMPERATURES AS IT APPEARS DEEPER MOISTURE WILL BE SOUTH AND EAST OF CENTRAL INDIANA WEDNESDAY NIGHT AND THURSDAY AHEAD OF FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST. WOULD ALSO NOT RULE OUT A SHOWER OR TOO MONDAY NIGHT AND TUESDAY AS A WEAK SYSTEM LIFTS NORTHEAST FROM THE SOUTHERN STATES TO THE APPALACHIANS...BUT LEFT IT OUT FOR NOW PER THE CENTRAL REGION INITIALIZATION. PREFERRED TO STAY CLOSER TO THE 00Z ECMWF WITH THE TIMING OF THE AFOREMENTIONED FRONT AS THE 00Z GFS LOOKS WAY TOO FAST BASED ON THE REMAINING LONG RANGE MODELS INCLUDING THE 144 HOUR GEM FRONTAL POSITION FROM THE 00Z RUN. HOWEVER...WITH MOISTURE LACKING...PULLED SMALL POPS FROM THE CENTRAL REGION INITIALIZATION AFTER COORDINATION WITH ILX...PAH...LMK AND ILN. WITH THE FORECAST AREA FOR THE MOST PART UNDER THE INFLUENCE OF HIGH PRESSURE AND LOW MEAN LEVEL RH...NOT EXPECTING MUCH CLOUD COVER THROUGH THE PERIOD. TEMPERATURES LOOK OK FROM THE CR INIT...EXCEPT WILL BUMP THEM UP A FEW DEGREES ON MONDAY BASED ON LITTLE EXPECTED CLOUD COVER AND 00Z ECMWF 850 MILLIBAR TEMPERATURES AROUND 10 DEGREE CELSIUS. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL IN THE MID TO UPPER 70S BY TUESDAY. && .AVIATION /DISCUSSION FOR THE 280600Z TAF ISSUANCE/... ISSUED AT 1200 AM EDT FRI SEP 28 2012 A PERIOD OF IFR CEILINGS FOG STILL LIKELY AT KIND...KHUF...KBMG... WHILE MVFR CEILINGS FOG STILL POSSIBLE AT KLAF. THIS WILL OCCUR LATE TONIGHT AND EARLY FRIDAY MAINLY FROM 09Z-14Z. SATELLITE AND WEATHER DEPICTION IS SHOWING AN AREA OF IFR CEILINGS ADVANCING ACROSS EAST CENTRAL INDIANA AND DEWPOINTS STILL AROUND 60 AT KIND...KHUF AND KBMG. WITH LIGHT WINDS AND MOIST GROUND AND SOME RADIATIONAL COOLING EXPECT IFR CONDITIONS TO GRADUALLY INCREASE LATE TONIGHT. DRIER AIR HAS SPREAD INTO KLAF...BUT WEATHER DEPICTION SHOWS SOME AREAS OF MVFR CEILINGS TO THE NORTHEAST OF KLAF. ON FRIDAY...STRATUS/FOG WILL LIFT BY MID TO LATE MORNING. CONVECTIVE TEMPERATURES WILL BE IN UPPER 60S...SO EXPECT MOSTLY BROKEN 4 TO 5 THOUSAND CLOUDS MIDDAY ON WITH CLEARING LATE FRIDAY AND EARLY FRIDAY EVENING. HIGH PRESSURE OVER THE GREAT LAKES WILL KEEP US UNDER A VERY LIGHT NORTH TO NORTHEAST FLOW FRIDAY AND FRIDAY EVENING. WINDS WILL BE ALMOST NEAR CALM OVERNIGHT AND 7 KNOTS OR LESS FRIDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....MK AVIATION...JH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
803 PM MDT SAT SEP 29 2012 .UPDATE... ISSUED AT 745 PM MDT SAT SEP 29 2012 JUST COMPLETED AN UPDATE THROUGH TOMORROW. LATEST MODELS CONFIRMED BY SURFACE ANALYSIS. SURFACE TROUGH STILL CLOSE TO THE FRONT AND MODELS HAVE THIS TOO FAR EAST. THE RUC FOLLOWED BY THE HRRR AND NAM WERE THE BEST MODELS WITH THIS. AS A RESULT WINDS WILL STAY FROM A SOUTH TO SOUTHEAST DIRECTION WELL INTO THE NIGHT ALLOWED AN INCREASE IN BLYR MOISTURE. BECAUSE OF ALL THIS INCREASED CLOUD COVER THROUGH THE NIGHT TO ACCOUNT FOR STRATUS AND ALSO INSERTED AREAS OF FOG OVER MOST OF THE AREA BEGINNING AT 06Z. ALSO ADJUSTED THE WINDS AND DEWPOINTS ACCORDING THE RUC...NAM...AND HRRR. CURRENTLY LITTLE IF ANY PRECIPITATION OCCURRING CLOSE TO THE FORECAST AREA. 00Z SOUNDINGS AND SATELLITE SHOW DEEP DRY LAYER AND LITTLE IF ANY LIFT ACROSS THE AREA AT THIS TIME. LIFT FROM INCOMING SURFACE TROUGH AND SHORTWAVE TROUGH AND DEEPER MOISTURE INCREASES AFTER 06Z...ESPECIALLY BY LATER IN THE NIGHT. ALSO ELEVATED CAPE INCREASES DRAMATICALLY WITH CINH THAT CAN BE OVERCOME. SO CONFINED A SLIGHT CHANCE OF THUNDERSTORMS UNTIL AFTER 06Z AND TO THE WEST OF THE COLORADO BORDER. THEN INCREASED THUNDERSTORM CHANCES AFTER 12Z AND GRADUALLY PROGRESS THIS ACROSS THE FORECAST AREA THROUGH THE DAY. && .SHORT TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 142 PM MDT SAT SEP 29 2012 NORTHWEST FLOW WILL BRING A SHORTWAVE INTO THE REGION LATE TONIGHT AND SUNDAY. A SURFACE TROUGH IN EASTERN COLORADO TONIGHT WILL SHIFT EAST ACROSS NORTHWEST KANSAS SUNDAY. SHORTWAVE TIMING WILL KEEP POPS NIL ACROSS MOST OF THE FA WITH EXCEPTION OF EASTERN COLORADO THIS EVENING. EASTERN COLORADO WILL BE THE FIRST ZONES TO HAVE ANY CHANCE THIS EVENING. WEAK DYNAMICS WILL THEN SPREAD INTO NORTHWEST KANSAS/EXTREME SOUTHWEST NEBRASKA AFTER 06Z SUNDAY. AFTER A MORNING LULL, THERE WILL BE A CHANCE OF THUNDERSTORMS ACROSS NORTHWEST KANSAS SUNDAY AFTERNOON GENERALLY EAST OF GOODLAND. BOUNDARY LAYER RH GETS HIGH ENOUGH TO SUPPORT PATCHY FOG OVER THE SOUTHEAST ZONES LATE TONIGHT. TEMPERATURES TONIGHT WILL FALL TO THE LOWER 50S. HIGHS SUNDAY WILL BE IN THE UPPER 70S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 220 PM MDT SAT SEP 29 2012 THE 12Z GFS AND ECMWF HAVE SLOWED THE PRE-FRONTAL SURFACE TROUGH DOWN FOR SUNDAY TO WHAT THE NAM HAS BEEN SHOWING THE LAST COUPLE OF DAYS. WITH THE LATEST GEFS MEMBERS ALSO SLOWING THE TROUGH DOWN WILL KEEP HIGHER PRECIP. CHANCES OVER THE EASTERN 1/3 OF THE AREA SUNDAY EVENING. EXTENDED THE SLIGHT CHANCES OVER THE EAST PAST MIDNIGHT DUE TO THE SLOWER TROUGH PASSAGE. MEANWHILE A COOLER AIR MASS WILL BEGIN TO MOVE INTO THE AREA DURING THE OVERNIGHT HOURS. MONDAY DRIER AIR MOVES INTO THE AREA SO WILL CONTINUE TO LEAVE THE FORECAST DRY DESPITE AN UPPER LEVEL SHORT WAVE TROUGH MOVING THROUGH DURING THE AFTERNOON. SURFACE WINDS WILL STRENGTHEN DURING THE AFTERNOON AS WINDS OF 20 TO 30 KTS MIX DOWN FROM 700MB. MONDAY NIGHT WILL ALSO BE DRY AS A SURFACE AND UPPER LEVEL RIDGE MOVE THROUGH AND POINT SOUNDINGS CONTINUE TO DRY OUT. FOR THE TUESDAY THROUGH SATURDAY PERIOD MODELS ARE COMING INTO BETTER AGREEMENT REGARDING THE TIMING OF THE UPPER LEVEL TROUGH DROPPING DOWN FROM CANADA INTO THE CENTRAL PLAINS. CURRENT MODEL RUNS HAVE THE TROUGH PASSING THROUGH THE AREA WEDNESDAY NIGHT...WITH THE MAJORITY OF THE LIFT WITH THE TROUGH NORTH OF THE AREA. WITH 1000-500MB RELATIVE HUMIDITY INCREASING AS THE TROUGH MOVES THROUGH...HAVE INTRODUCED PRECIP. CHANCES ALONG/NORTH OF THE NEBRASKA LINE. THE TROUGH BROADENS DURING THE LATTER HALF OF THE WORK WEEK AS ANOTHER SHORT WAVE TROUGH DIVES SOUTH ACROSS THE PLAINS...PASSING OVER THE AREA SATURDAY. MODELS CURRENTLY PLACE THE MAJORITY OF THE 1000-500MB RELATIVE HUMIDITY JUST NORTH OF THE AREA...SO WILL KEEP PRECIP. CHANCES IN THE SILENT CATEGORY FOR NOW. A STRONG COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY NIGHT. BELOW NORMAL TEMPERATURES CAN BE EXPECTED AFTER WEDNESDAY AS THE COOLER AIR MASS REMAINS OVER THE AREA. SOME LOCATIONS...ESPECIALLY THOSE IN LOW LYING AREAS MAY SEE FROST FRIDAY AND SATURDAY MORNING AS LOW TEMPERATURES APPROACH THE MID 30S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 553 PM MDT SAT SEP 29 2012 COMPLICATED SET OF TAFS. MODELS ARE SLOWER IN BRINGING SURFACE TROUGH THROUGH THE AREA TONIGHT. AS A RESULT THE WINDS WILL REMAIN FROM A SOUTH TO SOUTHEAST DIRECTION MOST OF THE NIGHT WHICH SHOULD KEEP THE LOW LEVEL AIR MASS MOIST. BELIEVE MODELS ARE UNDERDOING MOISTURE RETURN AS A RESULT. LATEST RUC AND NAM STILL HAVE THE WIND SHIFT TO THE WEST OF KGLD AT 12Z. THOSE MODELS PLUS THE HRRR HAVE STRATUS AND FOG FURTHER WEST THAN CURRENTLY DEPICTED. STRATUS AND FOG WILL DEVELOP AFTER 06Z. SO PUT IN MVFR CEILINGS AND VISIBILITIES UNTIL NEAR 15Z. AT THAT TIME...SURFACE TROUGH AND MID LEVEL SHORTWAVE TROUGH WILL BEGIN TO AFFECT THE AREA. MODELS SHOW A RATHER HIGH AMOUNT OF ELEVATED CAPE AND NOT A LOT OF CINH. DEEP LIFT AND MOISTURE LOOK TO CREATE A LINE OF THUNDERSTORMS DURING THE TIME. THE LINE LOOKS TO FORM NEAR KGLD AND IS POSSIBLE THAT IT COULD FORM JUST EAST OF KGLD. MORE SURE THAT KMCK WILL BE AFFECTED BY THUNDERSTORMS BY MIDDAY. SINCE IT WILL BE CLOSE AT KGLD AND THUNDERSTORMS NOT EXPECTED AT KMCK UNTIL THE LAST 6 HOURS OF THE PERIOD...CHOSE TO ONLY HAVE VCTS AT THIS TIME. WILL ADJUST WITH THE NEWER DATA BUT WOULD EXPECT THAT KMCK WILL HAVE A GOOD CHANCE TO BE AFFECTED BY THUNDERSTORMS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...FS LONG TERM...JTL AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
602 PM MDT SAT SEP 29 2012 .SHORT TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 142 PM MDT SAT SEP 29 2012 NORTHWEST FLOW WILL BRING A SHORTWAVE INTO THE REGION LATE TONIGHT AND SUNDAY. A SURFACE TROUGH IN EASTERN COLORADO TONIGHT WILL SHIFT EAST ACROSS NORTHWEST KANSAS SUNDAY. SHORTWAVE TIMING WILL KEEP POPS NIL ACROSS MOST OF THE FA WITH EXCEPTION OF EASTERN COLORADO THIS EVENING. EASTERN COLORADO WILL BE THE FIRST ZONES TO HAVE ANY CHANCE THIS EVENING. WEAK DYNAMICS WILL THEN SPREAD INTO NORTHWEST KANSAS/EXTREME SOUTHWEST NEBRASKA AFTER 06Z SUNDAY. AFTER A MORNING LULL, THERE WILL BE A CHANCE OF THUNDERSTORMS ACROSS NORTHWEST KANSAS SUNDAY AFTERNOON GENERALLY EAST OF GOODLAND. BOUNDARY LAYER RH GETS HIGH ENOUGH TO SUPPORT PATCHY FOG OVER THE SOUTHEAST ZONES LATE TONIGHT. TEMPERATURES TONIGHT WILL FALL TO THE LOWER 50S. HIGHS SUNDAY WILL BE IN THE UPPER 70S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 220 PM MDT SAT SEP 29 2012 THE 12Z GFS AND ECMWF HAVE SLOWED THE PRE-FRONTAL SURFACE TROUGH DOWN FOR SUNDAY TO WHAT THE NAM HAS BEEN SHOWING THE LAST COUPLE OF DAYS. WITH THE LATEST GEFS MEMBERS ALSO SLOWING THE TROUGH DOWN WILL KEEP HIGHER PRECIP. CHANCES OVER THE EASTERN 1/3 OF THE AREA SUNDAY EVENING. EXTENDED THE SLIGHT CHANCES OVER THE EAST PAST MIDNIGHT DUE TO THE SLOWER TROUGH PASSAGE. MEANWHILE A COOLER AIR MASS WILL BEGIN TO MOVE INTO THE AREA DURING THE OVERNIGHT HOURS. MONDAY DRIER AIR MOVES INTO THE AREA SO WILL CONTINUE TO LEAVE THE FORECAST DRY DESPITE AN UPPER LEVEL SHORT WAVE TROUGH MOVING THROUGH DURING THE AFTERNOON. SURFACE WINDS WILL STRENGTHEN DURING THE AFTERNOON AS WINDS OF 20 TO 30 KTS MIX DOWN FROM 700MB. MONDAY NIGHT WILL ALSO BE DRY AS A SURFACE AND UPPER LEVEL RIDGE MOVE THROUGH AND POINT SOUNDINGS CONTINUE TO DRY OUT. FOR THE TUESDAY THROUGH SATURDAY PERIOD MODELS ARE COMING INTO BETTER AGREEMENT REGARDING THE TIMING OF THE UPPER LEVEL TROUGH DROPPING DOWN FROM CANADA INTO THE CENTRAL PLAINS. CURRENT MODEL RUNS HAVE THE TROUGH PASSING THROUGH THE AREA WEDNESDAY NIGHT...WITH THE MAJORITY OF THE LIFT WITH THE TROUGH NORTH OF THE AREA. WITH 1000-500MB RELATIVE HUMIDITY INCREASING AS THE TROUGH MOVES THROUGH...HAVE INTRODUCED PRECIP. CHANCES ALONG/NORTH OF THE NEBRASKA LINE. THE TROUGH BROADENS DURING THE LATTER HALF OF THE WORK WEEK AS ANOTHER SHORT WAVE TROUGH DIVES SOUTH ACROSS THE PLAINS...PASSING OVER THE AREA SATURDAY. MODELS CURRENTLY PLACE THE MAJORITY OF THE 1000-500MB RELATIVE HUMIDITY JUST NORTH OF THE AREA...SO WILL KEEP PRECIP. CHANCES IN THE SILENT CATEGORY FOR NOW. A STRONG COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY NIGHT. BELOW NORMAL TEMPERATURES CAN BE EXPECTED AFTER WEDNESDAY AS THE COOLER AIR MASS REMAINS OVER THE AREA. SOME LOCATIONS...ESPECIALLY THOSE IN LOW LYING AREAS MAY SEE FROST FRIDAY AND SATURDAY MORNING AS LOW TEMPERATURES APPROACH THE MID 30S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 553 PM MDT SAT SEP 29 2012 COMPLICATED SET OF TAFS. MODELS ARE SLOWER IN BRINGING SURFACE TROUGH THROUGH THE AREA TONIGHT. AS A RESULT THE WINDS WILL REMAIN FROM A SOUTH TO SOUTHEAST DIRECTION MOST OF THE NIGHT WHICH SHOULD KEEP THE LOW LEVEL AIR MASS MOIST. BELIEVE MODELS ARE UNDERDOING MOISTURE RETURN AS A RESULT. LATEST RUC AND NAM STILL HAVE THE WIND SHIFT TO THE WEST OF KGLD AT 12Z. THOSE MODELS PLUS THE HRRR HAVE STRATUS AND FOG FURTHER WEST THAN CURRENTLY DEPICTED. STRATUS AND FOG WILL DEVELOP AFTER 06Z. SO PUT IN MVFR CEILINGS AND VISIBILITIES UNTIL NEAR 15Z. AT THAT TIME...SURFACE TROUGH AND MID LEVEL SHORTWAVE TROUGH WILL BEGIN TO AFFECT THE AREA. MODELS SHOW A RATHER HIGH AMOUNT OF ELEVATED CAPE AND NOT A LOT OF CINH. DEEP LIFT AND MOISTURE LOOK TO CREATE A LINE OF THUNDERSTORMS DURING THE TIME. THE LINE LOOKS TO FORM NEAR KGLD AND IS POSSIBLE THAT IT COULD FORM JUST EAST OF KGLD. MORE SURE THAT KMCK WILL BE AFFECTED BY THUNDERSTORMS BY MIDDAY. SINCE IT WILL BE CLOSE AT KGLD AND THUNDERSTORMS NOT EXPECTED AT KMCK UNTIL THE LAST 6 HOURS OF THE PERIOD...CHOSE TO ONLY HAVE VCTS AT THIS TIME. WILL ADJUST WITH THE NEWER DATA BUT WOULD EXPECT THAT KMCK WILL HAVE A GOOD CHANCE TO BE AFFECTED BY THUNDERSTORMS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...JTL AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
102 AM CDT FRI SEP 28 2012 ...UPDATE TO SYNOPSIS... .SYNOPSIS... ISSUED AT 100 AM CDT FRI SEP 28 2012 WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL TROUGH OF LOW PRESSURE PUSHING EAST ACROSS NORTHEASTERN COLORADO AND WESTERN NEBRASKA. A +80KT UPPER LEVEL JET IS CLIMBING NORTHEAST OUT OF THE DESERT SOUTHWEST INTO THE WESTERN HIGH PLAINS OF SOUTHWEST KANSAS AND JUST NOSING INTO WESTERN MISSOURI. NEAR THE SURFACE, AN AREA OF HIGH PRESSURE ACROSS THE UPPER MIDWEST IS HELPING INFLUENCE AN EAST TO SOUTHEASTERLY UPSLOPE FLOW ACROSS WESTERN KANSAS. SURFACE DEWPOINTS ARE PRIMARILY IN THE 50S(F) ACROSS CENTRAL AND SOUTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 237 PM CDT THU SEP 27 2012 THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE, IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT. THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000 J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS, AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE. AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13 INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH 3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST. FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS, WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO 50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK, BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 345 PM CDT THU SEP 27 2012 FRIDAY NIGHT: CONVECTION WILL QUICKLY BE ON THE WANE FRIDAY EVENING AS A 90 KT 250 HPA JET STREAK TRAVERSES QUICKLY ACROSS THE STATE AND AS DIURNAL INSTABILITY RAPIDLY DIMINISHES. AS A RESULT, HAVE RAMPED POPS DOWN SOONER ACROSS THE REGION BETWEEN FRIDAY EVENING AND TOWARDS MIDNIGHT SATURDAY. THE NEXT SENSIBLE WEATHER CONCERN HEADING INTO SATURDAY MORNING IS FOG. BUFKIT/BUFR FORECAST SOUNDINGS SHOW AN ENVIRONMENT THAT IS CONDUCIVE FOR RADIATIONAL FOG. THIS IS A RESULT OF HIGH PRESSURE BUILDING IN ACROSS KANSAS AND WINDS BECOMING LIGHT OR EVEN CALM. HAVE INSERTED AREAS OF FOG IN THE WX GRIDS AS BETTER CONFIDENCE OF FOG VIA THE AFOREMENTIONED SOUNDINGS AND PLAN VIEW RH PROGS IN THE BOUNDARY LAYER. SATURDAY THROUGH NEXT THURSDAY: THE FORECAST WILL BE FAIRLY DRY THROUGH MUCH OF THE PERIOD IN ASSOCIATION WITH UPPER LEVEL RIDGING, THE WARM PLUME SPREADING EAST, AND LACK OF REAL SURFACE MOISTURE & CONVERGENCE. THE EXCEPTION TO THIS IS SUNDAY EVENING. A SHORTWAVE TROUGH SKIRTING ACROSS THE NORTHERN PRAIRIES WILL USHER IN A COLD FRONT/TROF AXIS WHICH COULD BE THE IMPETUS FOR CONVECTION DURING THE AFTERNOON AND EARLY EVENING. WILL MAINLY USE THE 12Z ECMWF FOR GUIDANCE IN CONCERNING THIS CONVECTION FOR NOW. SLIGHT POPS LOOK REASONABLE FOR NOW AND RESULTED IN NOT MUCH CHANGE FROM THE PREVIOUS FORECAST. OTHERWISE, RELATIVELY HIGH 500 HPA HEIGHTS ARE EXPECTED ACROSS WESTERN KANSAS FOR MUCH OF NEXT WEEK. THE FLOW WILL BECOME MORE PERPENDICULAR TO THE ROCKIES BY MIDWEEK NEXT WEEK WHICH WILL RESULT IN LOWERING PRESSURES ACROSS THE LEE OF THE ROCKIES AND A CONTINUED WARM AIR ADVECTION PATTERN THROUGH THE LOWER ATMOSPHERE. AS A RESULT, EXPECT MODERATING TEMPERATURES THROUGH NEXT WEEK WITH NEAR TO ABOVE NORMAL HIGHS. THE 12Z ECMWF IS SHOWING A FAIRLY STRONG COLD FRONT TRAVERSING ACROSS THE KANSAS PRAIRIES BY NEXT THURSDAY. WILL NOT STRAY FROM WHAT THE ALLBLEND GIVES ME AS THE VALUES LOOK REASONABLE WITH HIGHS COOLING DOWN INTO THE 70S DEG F. UPPER LEVEL JET DYNAMICS WITH THIS FRONT LOOKS TO BE FAIRLY BROAD AND ELONGATED SO ANY SIGNIFICANT SYNOPTIC SCALE LIFT AND ASSOCIATED RESULTANT PRECIPITATION LOOKS TO REMAIN NORTH OF THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 AM CDT FRI SEP 28 2012 SHOWERS AND THUNDERSTORMS IN WEST CENTRAL AND SOUTHWEST KANSAS WILL CONTINUE TO TRACK EAST-SOUTHEAST INTO CENTRAL AND SOUTH CENTRAL KANSAS OVERNIGHT. MVFR CIGS/VSBYS WILL BE POSSIBLE WITH THE HEAVIEST RAINFALL. OTHERWISE, LOW LEVEL STRATUS IS EXPECTED TO DEVELOP LATER TONIGHT WITHIN A MOIST EAST TO SOUTHEASTERLY UPSLOPE FLOW ACROSS SOUTHWEST AND PORTIONS OF SOUTH CENTRAL KANSAS. MVFR CIGS/VSBYS ARE LIKELY IN THE VICINITY AND SOUTH OF KGCK AND KDDC...GENERALLY AFTER 07Z...WITH IFR CIGS/VSBYS POSSIBLE TOWARD DAYBREAK. CONDITIONS ARE THEN EXPECTED TO GRADUALLY IMPROVE THROUGH MID TO LATE MORNING. && .PRELIMINARY POINT TEMPS/POPS... DDC 75 55 76 54 / 50 20 10 10 GCK 73 54 75 54 / 40 20 10 10 EHA 72 53 76 54 / 30 20 10 10 LBL 74 55 76 54 / 40 20 10 10 HYS 75 53 76 53 / 40 20 10 10 P28 77 58 77 56 / 50 30 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJOHNSON SHORT TERM...BURKE LONG TERM...SUGDEN AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1205 AM CDT FRI SEP 28 2012 ...UPDATE TO AVIATION... .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 237 PM CDT THU SEP 27 2012 THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE, IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT. THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000 J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS, AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE. AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13 INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH 3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST. FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS, WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO 50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK, BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 345 PM CDT THU SEP 27 2012 FRIDAY NIGHT: CONVECTION WILL QUICKLY BE ON THE WANE FRIDAY EVENING AS A 90 KT 250 HPA JET STREAK TRAVERSES QUICKLY ACROSS THE STATE AND AS DIURNAL INSTABILITY RAPIDLY DIMINISHES. AS A RESULT, HAVE RAMPED POPS DOWN SOONER ACROSS THE REGION BETWEEN FRIDAY EVENING AND TOWARDS MIDNIGHT SATURDAY. THE NEXT SENSIBLE WEATHER CONCERN HEADING INTO SATURDAY MORNING IS FOG. BUFKIT/BUFR FORECAST SOUNDINGS SHOW AN ENVIRONMENT THAT IS CONDUCIVE FOR RADIATIONAL FOG. THIS IS A RESULT OF HIGH PRESSURE BUILDING IN ACROSS KANSAS AND WINDS BECOMING LIGHT OR EVEN CALM. HAVE INSERTED AREAS OF FOG IN THE WX GRIDS AS BETTER CONFIDENCE OF FOG VIA THE AFOREMENTIONED SOUNDINGS AND PLAN VIEW RH PROGS IN THE BOUNDARY LAYER. SATURDAY THROUGH NEXT THURSDAY: THE FORECAST WILL BE FAIRLY DRY THROUGH MUCH OF THE PERIOD IN ASSOCIATION WITH UPPER LEVEL RIDGING, THE WARM PLUME SPREADING EAST, AND LACK OF REAL SURFACE MOISTURE & CONVERGENCE. THE EXCEPTION TO THIS IS SUNDAY EVENING. A SHORTWAVE TROUGH SKIRTING ACROSS THE NORTHERN PRAIRIES WILL USHER IN A COLD FRONT/TROF AXIS WHICH COULD BE THE IMPETUS FOR CONVECTION DURING THE AFTERNOON AND EARLY EVENING. WILL MAINLY USE THE 12Z ECMWF FOR GUIDANCE IN CONCERNING THIS CONVECTION FOR NOW. SLIGHT POPS LOOK REASONABLE FOR NOW AND RESULTED IN NOT MUCH CHANGE FROM THE PREVIOUS FORECAST. OTHERWISE, RELATIVELY HIGH 500 HPA HEIGHTS ARE EXPECTED ACROSS WESTERN KANSAS FOR MUCH OF NEXT WEEK. THE FLOW WILL BECOME MORE PERPENDICULAR TO THE ROCKIES BY MIDWEEK NEXT WEEK WHICH WILL RESULT IN LOWERING PRESSURES ACROSS THE LEE OF THE ROCKIES AND A CONTINUED WARM AIR ADVECTION PATTERN THROUGH THE LOWER ATMOSPHERE. AS A RESULT, EXPECT MODERATING TEMPERATURES THROUGH NEXT WEEK WITH NEAR TO ABOVE NORMAL HIGHS. THE 12Z ECMWF IS SHOWING A FAIRLY STRONG COLD FRONT TRAVERSING ACROSS THE KANSAS PRAIRIES BY NEXT THURSDAY. WILL NOT STRAY FROM WHAT THE ALLBLEND GIVES ME AS THE VALUES LOOK REASONABLE WITH HIGHS COOLING DOWN INTO THE 70S DEG F. UPPER LEVEL JET DYNAMICS WITH THIS FRONT LOOKS TO BE FAIRLY BROAD AND ELONGATED SO ANY SIGNIFICANT SYNOPTIC SCALE LIFT AND ASSOCIATED RESULTANT PRECIPITATION LOOKS TO REMAIN NORTH OF THE REGION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 AM CDT FRI SEP 28 2012 SHOWERS AND THUNDERSTORMS IN WEST CENTRAL AND SOUTHWEST KANSAS WILL CONTINUE TO TRACK EAST-SOUTHEAST INTO CENTRAL AND SOUTH CENTRAL KANSAS OVERNIGHT. MVFR CIGS/VSBYS WILL BE POSSIBLE WITH THE HEAVIEST RAINFALL. OTHERWISE, LOW LEVEL STRATUS IS EXPECTED TO DEVELOP LATER TONIGHT WITHIN A MOIST EAST TO SOUTHEASTERLY UPSLOPE FLOW ACROSS SOUTHWEST AND PORTIONS OF SOUTH CENTRAL KANSAS. MVFR CIGS/VSBYS ARE LIKELY IN THE VICINITY AND SOUTH OF KGCK AND KDDC...GENERALLY AFTER 07Z...WITH IFR CIGS/VSBYS POSSIBLE TOWARD DAYBREAK. CONDITIONS ARE THEN EXPECTED TO GRADUALLY IMPROVE THROUGH MID TO LATE MORNING. && .PRELIMINARY POINT TEMPS/POPS... DDC 58 73 56 76 / 60 50 20 10 GCK 56 71 55 75 / 60 40 10 10 EHA 55 72 55 76 / 70 40 10 10 LBL 56 73 56 76 / 70 50 20 10 HYS 56 73 55 76 / 40 50 10 10 P28 60 75 60 77 / 50 60 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BURKE LONG TERM...SUGDEN AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1025 PM EDT SAT SEP 29 2012 .SYNOPSIS... AN UPPER LEVEL LOW WILL BRING SHOWERS TO THE AREA LATE TONIGHT THROUGH MUCH OF THE DAY ON SUNDAY. A FEW THUNDERSTORMS WILL BE POSSIBLE WITH SHOWERS SUNDAY AFTERNOON. HIGH PRESSURE WILL THEN RETURN DRY CONDITIONS FOR MONDAY. && .NEAR TERM /THROUGH SUNDAY/... 03Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADD MORE PATCHY FOG FOR LOCATIONS PRIMARILY SOUTHWEST OF PITTSBURGH. THE REST OF THE PREVIOUS DISCUSSION REMAINS THE SAME. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB CLOSED LOW CENTERED JUST EAST OF LAKE HURON IN ONTARIO. AN AXIS OF MID-LEVEL MOISTURE EXTENDS SOUTHWARD OF THE LOW INTO WESTERN PA. THE CYCLONIC FLOW AROUND THE LOW IS ADVECTING THAT MOISTURE EASTWARD WITH DRIER AIR UPSTREAM IN OHIO. VORT ENERGY IS SWINGING AROUND THE LOW...ACROSS LAKE ERIE...AND PROVIDING FORCING FOR SCATTERED SHOWERS IN NORTHEAST OHIO AND NORTHWEST PA. TONIGHT...THE UPPER LOW WILL SLIDE SOUTHWARD ACROSS LAKE ERIE AND INTO WESTERN PA BY DAWN. VORT LOBE OF ENERGY WILL SHIFT INTO EASTERN OHIO AND INCREASE THE CHANCES FOR SHOWERS OVERNIGHT...ESPECIALLY FOR LOCATIONS ALONG AND NORTH OF THE I-70 CORRIDOR. POPS OVERNIGHT INCREASE FROM SCHC EARLY TO LIKELY BY DAWN ACROSS THE I-80 CORRIDOR. AS THE DRIER AIR ADVECTS IN FROM OHIO SOME CLEARING WILL OCCUR FOR EASTERN OHIO AND NORTHERN WV. THIS WILL ALLOW FOR SOME PATCHY RADIATIONAL FOG TO DEVELOP WITH NEAR CALM WINDS. TEMPS OVERNIGHT ARE A HRRR/LAMP BLEND...WITH LOWS IN THE LOWER TO MID 40S ACROSS THE AREA. SUNDAY...THE UPPER LOW WILL PIVOT FROM WESTERN PA INTO NY. THE BEST FORCING WITH THE LOW WILL CROSS THE AREA IN THE 12Z-21Z WINDOW AS VORT ENERGY SWINGS ACROSS THE AREA. INCREASING INSTABILITY TO AROUND 300-500 J/KG SBCAPE WITH COOL TEMPS ALOFT (0C AROUND 7KFT) WILL SUPPORT THE SCHC OF THUNDERSTORMS IN THE LATE MORNING INTO THE AFTERNOON. WITH COOLER TEMPS ALOFT...NOT OUT OF THE QUESTION THAT GRAUPEL OR SMALL HAIL WOULD BE POSSIBLE IN THE STRONGER SHOWERS OR STORMS. CLOUD COVERAGE ALONG WITH COOLER AIR ADVECTING INTO THE AREA WITH THE LOW WILL KEEP TEMPS DOWN FOR HIGHS. HIGHS ARE A FEW DEGREES COOLER THAN A MAV/MET BLEND ACROSS MOST OF THE AREA, RANGING FROM MID 50S ALONG THE I-80 CORRIDOR TO THE MID 60S ACROSS THE LOWLANDS SOUTH OF I-70. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... UPPER LOW WILL PUSH EAST SUNDAY NIGHT...AND AS HIGH PRESSURE EDGES IN FROM THE WEST...HARD TO SAY HOW FAR LOW TEMPS WILL DROP SUNDAY NIGHT. IF CLOUDS BREAK EARLY ENOUGH...LOWS COULD EASILY DROP 5 DEGREES BELOW CURRENT FORECAST. INFLUENCE OF HIGH PRESSURE WILL BE SHORT LIVED AS SURFACE LOW PRESSURE DEVELOPS ALONG THE LOWER MISSISSIPPI AND MOVES NORTHEAST. STILL LOTS OF UNCERTAINTY WITH THE SYSTEM...INCLUDING INITIAL TIMING...AMOUNT OF RAIN...AND LOCATION OF HEAVIEST RAINFALL. ENSEMBLES SEEM AWFULLY FAST BRINGING THE RAIN IN...AND HAVE STUCK CLOSER TO NAM/GFS TIMING...WHICH KEEPS MOST PLACES DRY UNTIL LATE MONDAY EVENING. WILL NOT GET FANCY WITH LOCATION/TIMING OF HIGHEST QPF FOR NOW...BUT SOME LOCATIONS SHOULD BE A GOOD BET TO GET AT LEAST A HALF INCH OF RAIN. SOUTHEASTERLY FLOW WILL ALLOW FOR SOME TEMPERATURE RECOVERY...BRINGING HIGHS BACK INTO THE MID/UPPER 60S AND LOWER 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SHORT WAVE IN THE NORTHERN BRANCH MERGES WITH THE SOUTHERN BRANCH LOW TUESDAY EVENING IN THE WESTERN OHIO VALLEY AND WILL BRING SHOWERS FOR TUESDAY NIGHT INTO WEDNESDAY. THE UPPER LOW PUSHES INTO NEW YORK STATE BY WEDNESDAY EVENING...ENDING THE SHOWERS ACROSS THE FORECAST AREA. HIGH PRESSURE BUILDING INTO THE DISTRICT THURSDAY WILL BRING DRY WEATHER INTO THURSDAY NIGHT. A WEAK COLD FRONT PASSING ACROSS THE DISTRICT FRIDAY WILL BRING A CHANCE OF SHOWERS. HIGH PRESSURE BEHIND THE FRONT WILL BRING A RETURN OF DRY WEATHER FOR SATURDAY. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS CAN BE EXPECTED FOR TONIGHT WITH BROKEN STRATOCU VFR CEILINGS AND A FEW STRAY SHOWERS. PASSING UPPER LEVEL LOW CENTER WILL PROVIDE SCATTERED SHOWERS SUNDAY AND EARLY SUNDAY NIGHT WITH TIMES OF MVFR POSSIBLE BUT COVERAGE EXPECTED TO BE ENOUGH FOR INCLUSION IN TERMINALS. WITH COLD TEMPERATURES ALOFT ISOLATED THUNDERSTORMS ALSO POSSIBLE. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... SHOWERS WILL CONTINUE INTO THE FIRST HALF OF SUNDAY NIGHT FOLLOWED BY POSSIBLE PATCHY IFR FOG AND STRATUS. GENERAL VFR RETURNS FOR DAYTIME MONDAY...BUT A LOW PRESSURE SYSTEM WILL PROVIDE SHOWERS AND POSSIBLE RESTRICTIONS MONDAY NIGHT INTO WEDNESDAY. VFR RETURNS WEDNESDAY NIGHT INTO THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM SHORT TERM... LONG TERM... AVIATION...RES
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
816 PM EDT SAT SEP 29 2012 .SYNOPSIS... AN UPPER LEVEL LOW WILL BRING SHOWERS TO THE AREA LATE TONIGHT THROUGH MUCH OF THE DAY ON SUNDAY. A FEW THUNDERSTORMS WILL BE POSSIBLE WITH SHOWERS SUNDAY AFTERNOON. HIGH PRESSURE WILL THEN RETURN DRY CONDITIONS FOR MONDAY. && .NEAR TERM /THROUGH SUNDAY/... 00Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO MAKE THE ONSET OF SHOWERS EARLIER TONIGHT. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB CLOSED LOW CENTERED JUST EAST OF LAKE HURON IN ONTARIO. AN AXIS OF MID-LEVEL MOISTURE EXTENDS SOUTHWARD OF THE LOW INTO WESTERN PA. THE CYCLONIC FLOW AROUND THE LOW IS ADVECTING THAT MOISTURE EASTWARD WITH DRIER AIR UPSTREAM IN OHIO. VORT ENERGY IS SWINGING AROUND THE LOW...ACROSS LAKE ERIE...AND PROVIDING FORCING FOR SCATTERED SHOWERS IN NORTHEAST OHIO AND NORTHWEST PA. TONIGHT...THE UPPER LOW WILL SLIDE SOUTHWARD ACROSS LAKE ERIE AND INTO WESTERN PA BY DAWN. VORT LOBE OF ENERGY WILL SHIFT INTO EASTERN OHIO AND INCREASE THE CHANCES FOR SHOWERS OVERNIGHT...ESPECIALLY FOR LOCATIONS ALONG AND NORTH OF THE I-70 CORRIDOR. POPS OVERNIGHT INCREASE FROM SCHC EARLY TO LIKELY BY DAWN ACROSS THE I-80 CORRIDOR. AS THE DRIER AIR ADVECTS IN FROM OHIO SOME CLEARING WILL OCCUR FOR LOCATIONS SOUTH OF I-70. THIS WILL ALLOW FOR SOME PATCHY RADIATIONAL FOG TO DEVELOP WITH NEAR CALM WINDS. TEMPS OVERNIGHT ARE A HRRR/LAMP BLEND...WITH LOWS IN THE LOWER TO MID 40S ACROSS THE AREA. SUNDAY...THE UPPER LOW WILL PIVOT FROM WESTERN PA INTO NY. THE BEST FORCING WITH THE LOW WILL CROSS THE AREA IN THE 12Z-21Z WINDOW AS VORT ENERGY SWINGS ACROSS THE AREA. INCREASING INSTABILITY TO AROUND 300-500 J/KG SBCAPE WITH COOL TEMPS ALOFT (0C AROUND 7KFT) WILL SUPPORT THE SCHC OF THUNDERSTORMS IN THE LATE MORNING INTO THE AFTERNOON. WITH COOLER TEMPS ALOFT...NOT OUT OF THE QUESTION THAT GRAUPEL OR SMALL HAIL WOULD BE POSSIBLE IN THE STRONGER SHOWERS OR STORMS. CLOUD COVERAGE ALONG WITH COOLER AIR ADVECTING INTO THE AREA WITH THE LOW WILL KEEP TEMPS DOWN FOR HIGHS. HIGHS ARE A FEW DEGREES COOLER THAN A MAV/MET BLEND ACROSS MOST OF THE AREA, RANGING FROM MID 50S ALONG THE I-80 CORRIDOR TO THE MID 60S ACROSS THE LOWLANDS SOUTH OF I-70. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... UPPER LOW WILL PUSH EAST SUNDAY NIGHT...AND AS HIGH PRESSURE EDGES IN FROM THE WEST...HARD TO SAY HOW FAR LOW TEMPS WILL DROP SUNDAY NIGHT. IF CLOUDS BREAK EARLY ENOUGH...LOWS COULD EASILY DROP 5 DEGREES BELOW CURRENT FORECAST. INFLUENCE OF HIGH PRESSURE WILL BE SHORT LIVED AS SURFACE LOW PRESSURE DEVELOPS ALONG THE LOWER MISSISSIPPI AND MOVES NORTHEAST. STILL LOTS OF UNCERTAINTY WITH THE SYSTEM...INCLUDING INITIAL TIMING...AMOUNT OF RAIN...AND LOCATION OF HEAVIEST RAINFALL. ENSEMBLES SEEM AWFULLY FAST BRINGING THE RAIN IN...AND HAVE STUCK CLOSER TO NAM/GFS TIMING...WHICH KEEPS MOST PLACES DRY UNTIL LATE MONDAY EVENING. WILL NOT GET FANCY WITH LOCATION/TIMING OF HIGHEST QPF FOR NOW...BUT SOME LOCATIONS SHOULD BE A GOOD BET TO GET AT LEAST A HALF INCH OF RAIN. SOUTHEASTERLY FLOW WILL ALLOW FOR SOME TEMPERATURE RECOVERY...BRINGING HIGHS BACK INTO THE MID/UPPER 60S AND LOWER 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SHORT WAVE IN THE NORTHERN BRANCH MERGES WITH THE SOUTHERN BRANCH LOW TUESDAY EVENING IN THE WESTERN OHIO VALLEY AND WILL BRING SHOWERS FOR TUESDAY NIGHT INTO WEDNESDAY. THE UPPER LOW PUSHES INTO NEW YORK STATE BY WEDNESDAY EVENING...ENDING THE SHOWERS ACROSS THE FORECAST AREA. HIGH PRESSURE BUILDING INTO THE DISTRICT THURSDAY WILL BRING DRY WEATHER INTO THURSDAY NIGHT. A WEAK COLD FRONT PASSING ACROSS THE DISTRICT FRIDAY WILL BRING A CHANCE OF SHOWERS. HIGH PRESSURE BEHIND THE FRONT WILL BRING A RETURN OF DRY WEATHER FOR SATURDAY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS CAN BE EXPECTED FOR TONIGHT WITH BROKEN STRATOCU CEILINGS. THE STRATOCU WILL DIMINISH AFTER SUNSET WITH SOME SUFFICIENT RADIATIONAL COOLING TO PROMOTE MVFR FOG AROUND DAYBREAK SUNDAY. .OUTLOOK.../SUNDAY THROUGH THURSDAY/... PASSING UPPER LEVEL LOW CENTER WILL PROVIDE SCATTERED SHOWERS SUNDAY AND EARLY SUNDAY NIGHT WITH TIMES OF MVFR POSSIBLE. FOR NOW LEFT OUT OF TERMINALS AS MAY BE BRIEF. PATCHY IFR FOG AND STRATUS POSSIBLE LATE SUNDAY NIGHT. VFR RETURNS FOR DAYTIME MONDAY...BUT A LOW PRESSURE SYSTEM WILL PROVIDE SHOWERS AND POSSIBLE RESTRICTIONS TUESDAY INTO WEDNESDAY. VFR RETURNS WEDNESDAY NIGHT INTO THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM SHORT TERM... LONG TERM... AVIATION...RES
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1126 PM EDT SAT SEP 29 2012 .SYNOPSIS... ISSUED AT 316 PM EDT SAT SEP 29 2012 ONE AREA OF LOW PRESSURE WILL DEVELOP OVER NEW ENGLAND TONIGHT AND SUNDAY. THIS SYSTEM WILL BE TO FAR EAST TO CREATE RAIN HERE IN WESTERN MICHIGAN. HIGH PRESSURE IN ONTARIO WILL BUILD SOUTH INTO WESTERN LOWER MICHIGAN CREATING FAIR CONDITIONS WITH COOL NIGHTS AND NEAR SEASONABLY WARM DAYS INTO MONDAY. A WEAK COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TUESDAY INTO WEDNESDAY AS A LOW PRESSURE SYSTEM LIFTS OUT OF THE GULF OF MEXICO. AS A RESULT THE REGION MAY SEE SOME SHOWERS ARRIVING. && .UPDATE... ISSUED AT 1027 PM EDT SAT SEP 29 2012 NOT TOO CONCERNED WITH FROST POTENTIAL TONIGHT. MIXING REMAINS UP THROUGH THE NIGHT AND IT SEEMS FAIRLY LIKELY THAT SC WILL ENCROACH MUCH OF THE NE CWA BY MORNING. EVEN IF THE CLOUDS WERE TO BE THIN OR SCATTERED BELIEVE FROST THREAT IS VERY LOW. COULD BE REMOTE POCKETS OVER THE INTERIOR NORTH...BUT IT SHOULD BE TOO ISOLATED FOR ANY HEADLINE. INCREASED MIN TEMPS FOR OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 316 PM EDT SAT SEP 29 2012 THE MAIN CHALLENGE DEALS WITH THE RISK FOR FROST TONIGHT. OVERALL THE TREND OF TRACKING/FORMING THE SURFACE LOW FURTHER EAST CONTINUES. LOOKS LIKE IT WILL END UP OVER NEW ENGLAND. HERE IN WRN LOWER MI...SKIES WILL FEATURE MUCH LESS CLOUD COVER AS A RESULT IT APPEARS. THIS OPENS UP THE RISK FOR FROST ESPECIALLY WITH HIGH PRESSURE NOW SHOWN TO DROP SOUTHWARD OUT OF ONTARIO. HOWEVER THE HRRR RUC AND EVEN THE NAM ARE SHOWING LOW LEVEL MOISTURE AND A RISK FOR STRATUS TO DEVELOP OVER NORTHEAST LOWER TONIGHT...THEN DROP SOUTHWEST AND EXPAND INTO SOUTHWEST LOWER MI LATE TONIGHT. WILL KEEP THE FROST OUT OF THE FORECAST FOR NOW...BUT THIS SHOULD BE MONITORED CLOSELY AS HEADLINES MAY BE REQUIRED IF THE CLOUDS DO NOT DEVELOP. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 316 PM EDT SAT SEP 29 2012 TEMPS WILL AVERAGE ABOVE NORMAL TUESDAY BUT SOME CLOUDS FROM LOW PRESSURE TRACKING NE THROUGH THE OH VALLEY REGION WILL MOVE IN. WE HAVE INTRODUCED MENTION OF A SLIGHT CHC OF LIGHT RAIN SHOWERS FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT INTO WEDNESDAY IN ASSOCIATION WITH THAT SYSTEM (MAINLY SE OF GRR). TEMPS WILL REMAIN ABOVE NORMAL WEDNESDAY THROUGH THURSDAY AFTERNOON AS FLOW BECOMES SOUTHWESTERLY IN ADVANCE OF A STRONG COLD FRONT. THAT LOW PRESSURE SYSTEM AND COLD FRONT WILL BRING A CHC OF SHOWERS THURSDAY NIGHT THROUGH FRIDAY. AN UNSEASONABLY COOL AIRMASS WILL MOVE IN BEHIND THAT FRONT FRIDAY THROUGH SATURDAY WHEN HIGH TEMPS WILL ONLY REACH THE 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1125 PM EDT SAT SEP 29 2012 LITTLE CHANGE TO THE GOING FORECAST. STRATOCU CONTINUES TO DEVELOP OVER LAKE HURON AND IS MOVING SWWD. WE CONTINUED THE MVFR CIGS AT KLAN/KJXN LATE TONIGHT. THE REST OF THE TAFS SHOULD REMAIN VFR. && .MARINE... ISSUED AT 316 PM EDT SAT SEP 29 2012 WAVES WILL BE BUILDING AN REACH VALUES CLOSE TO SMALL CRAFT ADVISORY CRITERIA TONIGHT UP AROUND LITTLE AND BIG SABLE POINTS. THEN ON SUNDAY AS A NORTHERLY FLOW PERSISTS...WAVES SOUTH OF SOUTH HAVEN WILL ALSO END UP CLOSE TO CRITERIA. I THOUGHT MOST VALUES WOULD BE JUST UNDER CRITERIA SO NO HEADLINE AT THIS TIME. && .HYDROLOGY... ISSUED AT 316 PM EDT SAT SEP 29 2012 NO HYDRO ISSUES EXPECTED. ANY RAINFALL IS FORECASTED TO BE LIMITED AND NOT ENOUGH TO CAUSE SIGNIFICANT RISES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...JK SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...LAURENS AVIATION...93 HYDROLOGY...MJS MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1027 PM EDT SAT SEP 29 2012 .SYNOPSIS... ISSUED AT 316 PM EDT SAT SEP 29 2012 ONE AREA OF LOW PRESSURE WILL DEVELOP OVER NEW ENGLAND TONIGHT AND SUNDAY. THIS SYSTEM WILL BE TO FAR EAST TO CREATE RAIN HERE IN WESTERN MICHIGAN. HIGH PRESSURE IN ONTARIO WILL BUILD SOUTH INTO WESTERN LOWER MICHIGAN CREATING FAIR CONDITIONS WITH COOL NIGHTS AND NEAR SEASONABLY WARM DAYS INTO MONDAY. A WEAK COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TUESDAY INTO WEDNESDAY AS A LOW PRESSURE SYSTEM LIFTS OUT OF THE GULF OF MEXICO. AS A RESULT THE REGION MAY SEE SOME SHOWERS ARRIVING. && .UPDATE... ISSUED AT 1027 PM EDT SAT SEP 29 2012 NOT TOO CONCERNED WITH FROST POTENTIAL TONIGHT. MIXING REMAINS UP THROUGH THE NIGHT AND IT SEEMS FAIRLY LIKELY THAT SC WILL ENCROACH MUCH OF THE NE CWA BY MORNING. EVEN IF THE CLOUDS WERE TO BE THIN OR SCATTERED BELIEVE FROST THREAT IS VERY LOW. COULD BE REMOTE POCKETS OVER THE INTERIOR NORTH...BUT IT SHOULD BE TOO ISOLATED FOR ANY HEADLINE. INCREASED MIN TEMPS FOR OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 316 PM EDT SAT SEP 29 2012 THE MAIN CHALLENGE DEALS WITH THE RISK FOR FROST TONIGHT. OVERALL THE TREND OF TRACKING/FORMING THE SURFACE LOW FURTHER EAST CONTINUES. LOOKS LIKE IT WILL END UP OVER NEW ENGLAND. HERE IN WRN LOWER MI...SKIES WILL FEATURE MUCH LESS CLOUD COVER AS A RESULT IT APPEARS. THIS OPENS UP THE RISK FOR FROST ESPECIALLY WITH HIGH PRESSURE NOW SHOWN TO DROP SOUTHWARD OUT OF ONTARIO. HOWEVER THE HRRR RUC AND EVEN THE NAM ARE SHOWING LOW LEVEL MOISTURE AND A RISK FOR STRATUS TO DEVELOP OVER NORTHEAST LOWER TONIGHT...THEN DROP SOUTHWEST AND EXPAND INTO SOUTHWEST LOWER MI LATE TONIGHT. WILL KEEP THE FROST OUT OF THE FORECAST FOR NOW...BUT THIS SHOULD BE MONITORED CLOSELY AS HEADLINES MAY BE REQUIRED IF THE CLOUDS DO NOT DEVELOP. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 316 PM EDT SAT SEP 29 2012 TEMPS WILL AVERAGE ABOVE NORMAL TUESDAY BUT SOME CLOUDS FROM LOW PRESSURE TRACKING NE THROUGH THE OH VALLEY REGION WILL MOVE IN. WE HAVE INTRODUCED MENTION OF A SLIGHT CHC OF LIGHT RAIN SHOWERS FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT INTO WEDNESDAY IN ASSOCIATION WITH THAT SYSTEM (MAINLY SE OF GRR). TEMPS WILL REMAIN ABOVE NORMAL WEDNESDAY THROUGH THURSDAY AFTERNOON AS FLOW BECOMES SOUTHWESTERLY IN ADVANCE OF A STRONG COLD FRONT. THAT LOW PRESSURE SYSTEM AND COLD FRONT WILL BRING A CHC OF SHOWERS THURSDAY NIGHT THROUGH FRIDAY. AN UNSEASONABLY COOL AIRMASS WILL MOVE IN BEHIND THAT FRONT FRIDAY THROUGH SATURDAY WHEN HIGH TEMPS WILL ONLY REACH THE 50S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 732 PM EDT SAT SEP 29 2012 SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE EVENING. HOWEVER A POTENT UPPER LOW MAY GENERATE SOME MVFR CIGS OVER THE ERN CWA TONIGHT. NE FLOW WILL DEVELOP. WARMER AIR FLOWING OVER LAKE HURON WILL INTERACT WITH THE COOLER LAND TEMPS SHOULD PRODUCE SOME STRATOCU. THE QUESTION IS HOW MUCH AND WHERE. STARTED WITH THE ERN TAFS AFTER 06Z. IT/S POSSIBLE SOME STRATOCU COULD MOVE OVER KGRR LATE TONIGHT BUT OPTED TO KEEP THAT OUT OF THE TAFS FOR NOW. && .MARINE... ISSUED AT 316 PM EDT SAT SEP 29 2012 WAVES WILL BE BUILDING AN REACH VALUES CLOSE TO SMALL CRAFT ADVISORY CRITERIA TONIGHT UP AROUND LITTLE AND BIG SABLE POINTS. THEN ON SUNDAY AS A NORTHERLY FLOW PERSISTS...WAVES SOUTH OF SOUTH HAVEN WILL ALSO END UP CLOSE TO CRITERIA. I THOUGHT MOST VALUES WOULD BE JUST UNDER CRITERIA SO NO HEADLINE AT THIS TIME. && .HYDROLOGY... ISSUED AT 316 PM EDT SAT SEP 29 2012 NO HYDRO ISSUES EXPECTED. ANY RAINFALL IS FORECASTED TO BE LIMITED AND NOT ENOUGH TO CAUSE SIGNIFICANT RISES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...JK SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...LAURENS AVIATION...93 HYDROLOGY...MJS MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
732 PM EDT SAT SEP 29 2012 .SYNOPSIS... ISSUED AT 316 PM EDT SAT SEP 29 2012 ONE AREA OF LOW PRESSURE WILL DEVELOP OVER NEW ENGLAND TONIGHT AND SUNDAY. THIS SYSTEM WILL BE TO FAR EAST TO CREATE RAIN HERE IN WESTERN MICHIGAN. HIGH PRESSURE IN ONTARIO WILL BUILD SOUTH INTO WESTERN LOWER MICHIGAN CREATING FAIR CONDITIONS WITH COOL NIGHTS AND NEAR SEASONABLY WARM DAYS INTO MONDAY. A WEAK COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TUESDAY INTO WEDNESDAY AS A LOW PRESSURE SYSTEM LIFTS OUT OF THE GULF OF MEXICO. AS A RESULT THE REGION MAY SEE SOME SHOWERS ARRIVING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 316 PM EDT SAT SEP 29 2012 THE MAIN CHALLENGE DEALS WITH THE RISK FOR FROST TONIGHT. OVERALL THE TREND OF TRACKING/FORMING THE SURFACE LOW FURTHER EAST CONTINUES. LOOKS LIKE IT WILL END UP OVER NEW ENGLAND. HERE IN WRN LOWER MI...SKIES WILL FEATURE MUCH LESS CLOUD COVER AS A RESULT IT APPEARS. THIS OPENS UP THE RISK FOR FROST ESPECIALLY WITH HIGH PRESSURE NOW SHOWN TO DROP SOUTHWARD OUT OF ONTARIO. HOWEVER THE HRRR RUC AND EVEN THE NAM ARE SHOWING LOW LEVEL MOISTURE AND A RISK FOR STRATUS TO DEVELOP OVER NORTHEAST LOWER TONIGHT...THEN DROP SOUTHWEST AND EXPAND INTO SOUTHWEST LOWER MI LATE TONIGHT. WILL KEEP THE FROST OUT OF THE FORECAST FOR NOW...BUT THIS SHOULD BE MONITORED CLOSELY AS HEADLINES MAY BE REQUIRED IF THE CLOUDS DO NOT DEVELOP. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 316 PM EDT SAT SEP 29 2012 TEMPS WILL AVERAGE ABOVE NORMAL TUESDAY BUT SOME CLOUDS FROM LOW PRESSURE TRACKING NE THROUGH THE OH VALLEY REGION WILL MOVE IN. WE HAVE INTRODUCED MENTION OF A SLIGHT CHC OF LIGHT RAIN SHOWERS FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT INTO WEDNESDAY IN ASSOCIATION WITH THAT SYSTEM (MAINLY SE OF GRR). TEMPS WILL REMAIN ABOVE NORMAL WEDNESDAY THROUGH THURSDAY AFTERNOON AS FLOW BECOMES SOUTHWESTERLY IN ADVANCE OF A STRONG COLD FRONT. THAT LOW PRESSURE SYSTEM AND COLD FRONT WILL BRING A CHC OF SHOWERS THURSDAY NIGHT THROUGH FRIDAY. AN UNSEASONABLY COOL AIRMASS WILL MOVE IN BEHIND THAT FRONT FRIDAY THROUGH SATURDAY WHEN HIGH TEMPS WILL ONLY REACH THE 50S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 732 PM EDT SAT SEP 29 2012 SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE EVENING. HOWEVER A POTENT UPPER LOW MAY GENERATE SOME MVFR CIGS OVER THE ERN CWA TONIGHT. NE FLOW WILL DEVELOP. WARMER AIR FLOWING OVER LAKE HURON WILL INTERACT WITH THE COOLER LAND TEMPS SHOULD PRODUCE SOME STRATOCU. THE QUESTION IS HOW MUCH AND WHERE. STARTED WITH THE ERN TAFS AFTER 06Z. IT/S POSSIBLE SOME STRATOCU COULD MOVE OVER KGRR LATE TONIGHT BUT OPTED TO KEEP THAT OUT OF THE TAFS FOR NOW. && .MARINE... ISSUED AT 316 PM EDT SAT SEP 29 2012 WAVES WILL BE BUILDING AN REACH VALUES CLOSE TO SMALL CRAFT ADVISORY CRITERIA TONIGHT UP AROUND LITTLE AND BIG SABLE POINTS. THEN ON SUNDAY AS A NORTHERLY FLOW PERSISTS...WAVES SOUTH OF SOUTH HAVEN WILL ALSO END UP CLOSE TO CRITERIA. I THOUGHT MOST VALUES WOULD BE JUST UNDER CRITERIA SO NO HEADLINE AT THIS TIME. && .HYDROLOGY... ISSUED AT 316 PM EDT SAT SEP 29 2012 NO HYDRO ISSUES EXPECTED. ANY RAINFALL IS FORECASTED TO BE LIMITED AND NOT ENOUGH TO CAUSE SIGNIFICANT RISES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...LAURENS AVIATION...93 HYDROLOGY...MJS MARINE...MJS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1135 AM CDT FRI SEP 28 2012 .UPDATE... ISSUED AT 1052 AM CDT FRI SEP 28 2012 HAVE MADE SOME MINOR UPDATES TO PRECIP AND CLOUD COVERAGE TO ACCOUNT FOR ONGOING TRENDS. SHOWERS OVER THE SRN PART OF THE CWA ARE DIMINISHING AND DO NOT SEE MUCH MORE THAN SCT COVERAGE THIS MORNING WITH JUST A FEW SHOWERS THIS AFTERNOON. CLEARING LINE SHOULD ALSO PUSH SLOWLY SOUTH AS NORTH-NORTHEAST WINDS ADVECT DRIER AIR INTO THE REGION. GOING HIGHS STILL LOOK ON TRACK. BRITT && .SHORT TERM... ISSUED AT 313 AM CDT FRI SEP 28 2012 (TODAY) THE PRIMARY FCST ISSUE FOR THIS FCST PD IS DETERMINING WHICH PARTS OF THE CWA ARE MOST LIKELY TO RECEIVE PCPN THROUGH 00Z. 07Z METARS AND MSAS SATURATED EQUIVALENT POTENTIAL TEMPERATURE FIELDS DEPICTED AN E-W ORIENTED BDRY BISECTING THE CWA. ALOFT...A SHORTWAVE TROF WAS LOCATED OVER CENTRAL AND WRN MO PER WATER VAPOR SATELLITE IMAGERY ALONG WITH AN ANTICYCLONICALLY CURVED JET STREAK AT H25 OVER CENTRAL IL NOTED ON THE LATEST RUC ANALYSIS AND SUPPORTED BY AREA VWP/PROFILER OBS. LARGE SCALE LIFT AHEAD OF THIS SHORTWAVE AND RER DYNAMICS ASSOCIATED WITH THE CURVED JET STREAK WERE SUPPORTING ISO-SCT SHRA ACROSS THE SRN HALF OF THE CWA...MAINLY ALONG AND S OF THE BDRY. THESE FEATURES ARE EXPECTED TO MOVE E OF THE CWA BY DAYBREAK WITH PCPN DIMINISHING DUE TO SUBSIDENCE IN THE WAKE OF THE DEPARTING SHORTWAVE AND DRIER AIR FILTERING IN TO THE REGION AS A SFC HIGH SINKS SWD. HOWEVER...THE BDRY WILL STILL BE PRESENT /ALBEIT SLOWLY SINKING SWD/ ACROSS PART OF THE AREA THROUGH THE AFTN HOURS...AND ANOTHER SHORTWAVE WAS LOCATED UPSTREAM AT 07Z NEAR THE KS/CO BORDER. DESPITE THE DRIER AIR FILTERING IN FROM THE NORTH...MODELS DO SHOW SOME 300-250MB DIVERGENCE ACROSS THE SRN CWA DURING THE DAY AND WHEN COMBINED WITH THE CO/KS SHORTWAVE THERE MAY BE ENOUGH SUPPORT FOR ISO-SCT SHRA THIS AFTN INVOF THE BDRY. KANOFSKY && .LONG TERM... ISSUED AT 300 AM CDT FRI SEP 28 2012 (TONIGHT - TUESDAY) ZONAL FLOW ALOFT THAT HAS GIVEN US A PROLONGED PERIOD OF UNSETTLED WX THIS PAST WEEK WILL TRANSITION TO NW TO N FLOW THAT SHOULD GIVE US A QUIETER PERIOD FOR A BIT. THIS CHANGE IN FLOW WILL INITIALLY BE HELPED OUT BY A POLAR VORTEX DIGGING INTO THE GRTLKS REGION THIS WEEKEND AND LATER BY A TROF THAT DIGS INTO THE CNTRL AND S CNTRL CONUS EARLY NEXT WEEK...WITH BOTH OF THESE FEATURES EXPECTED TO BE FAR ENOUGH AWAY TO HAVE LITTLE IMPACT. THE SFC IS EXPECTED TO HAVE A WEAK RIDGE PREVAILING FOR MUCH OF THIS PERIOD...ALTHOUGH A TROF WILL TAKE A SWIPE MAINLY AT THE IL SIDE ON SATURDAY NIGHT AND SUNDAY. BELOW NORMAL PWATS FOR THIS WEEKEND...A STABLE ATMOSPHERE...AND MOST IMPORTANTLY...LIFTING MECHANISMS TOO WEAK...SHOULD PRECLUDE ANY PCPN DEVELOPMENT THIS WEEKEND. NEAR AVERAGE TEMPS FOR LATE SEPTEMBER ARE EXPECTED...WHICH FAVOR THE MAV MOS NUMBERS WHICH IN MOST CASES ARE RUNNING A BIT LOWER THAN THE MET MOS. UP UNTIL THIS POINT THERE IS GOOD AGREEMENT BETWEEN THE MODELS. WE START TO SEE SOME DISAGREEMENT BEGINNING MONDAY WHERE THE ECMWF DRAGS A CDFNT THRU WHEREAS THE GFS KEEPS IT WEST OF THE FA WHERE IT THEN DISSIPATES IT AND RE-ESTABLISHES THE RIDGE. IT APPEARS WITH RESPECT TO THE BOTTOM LINE...THIS IS A MINOR QUIBBLE AS THE ECMWF STRUGGLES TO BRING ANY MOISTURE UP IN TIME FOR WHEN IT BRINGS THE CDFNT THRU...AND IF THIS DOES HAPPEN...SHOULD GO THRU DRY AS A SYSTEM FURTHER TO THE SE WILL STEAL THE SHOW AND HOG THE SENSIBLE WX. WILL NEED TO WATCH EXACTLY WHERE THIS SERN CONUS SYSTEM GOES AS IT COULD EDGE SOME PARTS OF SERN MO AND SRN IL ON MONDAY. TEMPS COULD BE A BIGGER SOURCE OF ERROR HERE...NAMELY IF THE FRONT ACTUALLY GOES THRU OR NOT...BUT TEMPS AT OR A BIT ABOVE AVERAGE SEEM THE BETTER BET. (WEDNESDAY - THURSDAY) GFS AND ECMWF CONTINUE THEIR STANDOFF INTO THE MID AND LATER PARTS OF NEXT WEEK. THE ECMWF FEATURES ZONAL FLOW RETURNING BUT MORE IN THE FORM OF A PLATEAUED OUT BUILDING RIDGE FROM THE SW WHILE THE GFS MAINTAINS A TROF OVER THE LOWER MS VALLEY WHICH THEN LIFTS NEWD INTO THE LOWER OH VALLEY AS IT GETS ABSORBED. EITHER WAY...BOTH ARE TAKING ANOTHER...STRONGER...CDFNT THRU THE AREA DURING THIS TIME BUT THE DIFFS IN FLOW ALOFT WILL MAKE FOR A TIMING QUANDARY WITH THE FRONT BY AS MUCH AS 24HRS. THE GFS TAKES THE CDFNT THRU WEDNESDAY WHILE THE ECMWF DOESN/T UNTIL THURSDAY. BUT ONCE AGAIN...MOISTURE RETURN FROM THE GULF IS EFFECTIVELY BLOCKED AND WILL MAKE FOR LIMITED AMOUNTS TO WORK WITH. VERY QUESTIONABLE WHETHER OR NOT FRONT CAN GENERATE PCPN HERE BUT IF STRENGTH OF COLD AIR BEHIND IS SUFFICIENT...IT MAY. ABOVE AVERAGE TEMPS TO CONTINUE AHEAD OF FRONT. TES && .AVIATION... ISSUED AT 1134 AM CDT FRI SEP 28 2012 GENERALLY DRY AND VFR CONDITIONS WILL OCCUR AT THE TAF SITES THROUGH THE END OF PERIOD. MVFR CIGS OVER THE EASTERN OZARKS WILL GRADUALLY IMPROVE TO VFR THROUGH THE AFTERNOON. DRY AIR ADVECTION AND MIXING SHOULD BE ENOUGH TO LIMIT FOG DEVELOPMENT EXCEPT AT KCPS AND KSUS LATE TONIGHT. EXPECT WINDS TO TURN CALM AT THESE AIRPORTS WHICH SHOULD ALLOW ENOUGH COOLING TO CAUSE SOME MVFR VSBYS IN BR BETWEEN 09-14Z. SPECIFICS FOR KSTL...EXPECT DRY AND VFR CONDITIONS THE NEXT 30 HOURS WITH LIGHT NORTH TO NORTHEAST WINDS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1053 AM CDT FRI SEP 28 2012 .UPDATE... ISSUED AT 1052 AM CDT FRI SEP 28 2012 HAVE MADE SOME MINOR UPDATES TO PRECIP AND CLOUD COVERAGE TO ACCOUNT FOR ONGOING TRENDS. SHOWERS OVER THE SRN PART OF THE CWA ARE DIMINISHING AND DO NOT SEE MUCH MORE THAN SCT COVERAGE THIS MORNING WITH JUST A FEW SHOWERS THIS AFTERNOON. CLEARING LINE SHOULD ALSO PUSH SLOWLY SOUTH AS NORTH-NORTHEAST WINDS ADVECT DRIER AIR INTO THE REGION. GOING HIGHS STILL LOOK ON TRACK. BRITT && .SHORT TERM... ISSUED AT 313 AM CDT FRI SEP 28 2012 (TODAY) THE PRIMARY FCST ISSUE FOR THIS FCST PD IS DETERMINING WHICH PARTS OF THE CWA ARE MOST LIKELY TO RECEIVE PCPN THROUGH 00Z. 07Z METARS AND MSAS SATURATED EQUIVALENT POTENTIAL TEMPERATURE FIELDS DEPICTED AN E-W ORIENTED BDRY BISECTING THE CWA. ALOFT...A SHORTWAVE TROF WAS LOCATED OVER CENTRAL AND WRN MO PER WATER VAPOR SATELLITE IMAGERY ALONG WITH AN ANTICYCLONICALLY CURVED JET STREAK AT H25 OVER CENTRAL IL NOTED ON THE LATEST RUC ANALYSIS AND SUPPORTED BY AREA VWP/PROFILER OBS. LARGE SCALE LIFT AHEAD OF THIS SHORTWAVE AND RER DYNAMICS ASSOCIATED WITH THE CURVED JET STREAK WERE SUPPORTING ISO-SCT SHRA ACROSS THE SRN HALF OF THE CWA...MAINLY ALONG AND S OF THE BDRY. THESE FEATURES ARE EXPECTED TO MOVE E OF THE CWA BY DAYBREAK WITH PCPN DIMINISHING DUE TO SUBSIDENCE IN THE WAKE OF THE DEPARTING SHORTWAVE AND DRIER AIR FILTERING IN TO THE REGION AS A SFC HIGH SINKS SWD. HOWEVER...THE BDRY WILL STILL BE PRESENT /ALBEIT SLOWLY SINKING SWD/ ACROSS PART OF THE AREA THROUGH THE AFTN HOURS...AND ANOTHER SHORTWAVE WAS LOCATED UPSTREAM AT 07Z NEAR THE KS/CO BORDER. DESPITE THE DRIER AIR FILTERING IN FROM THE NORTH...MODELS DO SHOW SOME 300-250MB DIVERGENCE ACROSS THE SRN CWA DURING THE DAY AND WHEN COMBINED WITH THE CO/KS SHORTWAVE THERE MAY BE ENOUGH SUPPORT FOR ISO-SCT SHRA THIS AFTN INVOF THE BDRY. KANOFSKY && .LONG TERM... ISSUED AT 300 AM CDT FRI SEP 28 2012 (TONIGHT - TUESDAY) ZONAL FLOW ALOFT THAT HAS GIVEN US A PROLONGED PERIOD OF UNSETTLED WX THIS PAST WEEK WILL TRANSITION TO NW TO N FLOW THAT SHOULD GIVE US A QUIETER PERIOD FOR A BIT. THIS CHANGE IN FLOW WILL INITIALLY BE HELPED OUT BY A POLAR VORTEX DIGGING INTO THE GRTLKS REGION THIS WEEKEND AND LATER BY A TROF THAT DIGS INTO THE CNTRL AND S CNTRL CONUS EARLY NEXT WEEK...WITH BOTH OF THESE FEATURES EXPECTED TO BE FAR ENOUGH AWAY TO HAVE LITTLE IMPACT. THE SFC IS EXPECTED TO HAVE A WEAK RIDGE PREVAILING FOR MUCH OF THIS PERIOD...ALTHOUGH A TROF WILL TAKE A SWIPE MAINLY AT THE IL SIDE ON SATURDAY NIGHT AND SUNDAY. BELOW NORMAL PWATS FOR THIS WEEKEND...A STABLE ATMOSPHERE...AND MOST IMPORTANTLY...LIFTING MECHANISMS TOO WEAK...SHOULD PRECLUDE ANY PCPN DEVELOPMENT THIS WEEKEND. NEAR AVERAGE TEMPS FOR LATE SEPTEMBER ARE EXPECTED...WHICH FAVOR THE MAV MOS NUMBERS WHICH IN MOST CASES ARE RUNNING A BIT LOWER THAN THE MET MOS. UP UNTIL THIS POINT THERE IS GOOD AGREEMENT BETWEEN THE MODELS. WE START TO SEE SOME DISAGREEMENT BEGINNING MONDAY WHERE THE ECMWF DRAGS A CDFNT THRU WHEREAS THE GFS KEEPS IT WEST OF THE FA WHERE IT THEN DISSIPATES IT AND RE-ESTABLISHES THE RIDGE. IT APPEARS WITH RESPECT TO THE BOTTOM LINE...THIS IS A MINOR QUIBBLE AS THE ECMWF STRUGGLES TO BRING ANY MOISTURE UP IN TIME FOR WHEN IT BRINGS THE CDFNT THRU...AND IF THIS DOES HAPPEN...SHOULD GO THRU DRY AS A SYSTEM FURTHER TO THE SE WILL STEAL THE SHOW AND HOG THE SENSIBLE WX. WILL NEED TO WATCH EXACTLY WHERE THIS SERN CONUS SYSTEM GOES AS IT COULD EDGE SOME PARTS OF SERN MO AND SRN IL ON MONDAY. TEMPS COULD BE A BIGGER SOURCE OF ERROR HERE...NAMELY IF THE FRONT ACTUALLY GOES THRU OR NOT...BUT TEMPS AT OR A BIT ABOVE AVERAGE SEEM THE BETTER BET. (WEDNESDAY - THURSDAY) GFS AND ECMWF CONTINUE THEIR STANDOFF INTO THE MID AND LATER PARTS OF NEXT WEEK. THE ECMWF FEATURES ZONAL FLOW RETURNING BUT MORE IN THE FORM OF A PLATEAUED OUT BUILDING RIDGE FROM THE SW WHILE THE GFS MAINTAINS A TROF OVER THE LOWER MS VALLEY WHICH THEN LIFTS NEWD INTO THE LOWER OH VALLEY AS IT GETS ABSORBED. EITHER WAY...BOTH ARE TAKING ANOTHER...STRONGER...CDFNT THRU THE AREA DURING THIS TIME BUT THE DIFFS IN FLOW ALOFT WILL MAKE FOR A TIMING QUANDARY WITH THE FRONT BY AS MUCH AS 24HRS. THE GFS TAKES THE CDFNT THRU WEDNESDAY WHILE THE ECMWF DOESN/T UNTIL THURSDAY. BUT ONCE AGAIN...MOISTURE RETURN FROM THE GULF IS EFFECTIVELY BLOCKED AND WILL MAKE FOR LIMITED AMOUNTS TO WORK WITH. VERY QUESTIONABLE WHETHER OR NOT FRONT CAN GENERATE PCPN HERE BUT IF STRENGTH OF COLD AIR BEHIND IS SUFFICIENT...IT MAY. ABOVE AVERAGE TEMPS TO CONTINUE AHEAD OF FRONT. TES && .AVIATION... ISSUED AT 615 AM CDT FRI SEP 28 2012 ISO-SCT SHRA INVOF KCOU AND THE STL METRO AREA TAF SITES ARE EXPECTED TO CONTINUE FOR A FEW MORE HOURS UNTIL A SLOWLY MOVING FRONT FINALLY SINKS SOUTH OF THE TERMINALS. ISO-SCT PCPN WILL STILL BE POSSIBLE ALONG AND SOUTH OF THE FRONT TODAY BUT THIS SHOULD BE LIMITED TO AREAS SOUTH OF THE TAF SITES. MVFR CIGS ARE EXPECTED TO IMPROVE THIS MORNING DUE TO A COMBINATION OF DIURNAL MIXING...DRIER AIR NORTH OF THE FRONT...AND THE DEPARTURE OF THE FRONTAL BDRY. SPECIFICS FOR KSTL...SCT SHRA INVOF KSTL ARE EXPECTED FOR A FEW MORE HOURS UNTIL A SLOWLY MOVING FRONT SINKS SOUTH OF THE TERMINAL. MVFR CIGS ARE EXPECTED TO IMPROVE TO VFR LATER THIS MORNING ONCE THE BDRY SINKS FARTHER SOUTH OF KSTL. KANOFSKY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
622 AM CDT FRI SEP 28 2012 .SHORT TERM... ISSUED AT 313 AM CDT FRI SEP 28 2012 (TODAY) THE PRIMARY FCST ISSUE FOR THIS FCST PD IS DETERMINING WHICH PARTS OF THE CWA ARE MOST LIKELY TO RECEIVE PCPN THROUGH 00Z. 07Z METARS AND MSAS SATURATED EQUIVALENT POTENTIAL TEMPERATURE FIELDS DEPICTED AN E-W ORIENTED BDRY BISECTING THE CWA. ALOFT...A SHORTWAVE TROF WAS LOCATED OVER CENTRAL AND WRN MO PER WATER VAPOR SATELLITE IMAGERY ALONG WITH AN ANTICYCLONICALLY CURVED JET STREAK AT H25 OVER CENTRAL IL NOTED ON THE LATEST RUC ANALYSIS AND SUPPORTED BY AREA VWP/PROFILER OBS. LARGE SCALE LIFT AHEAD OF THIS SHORTWAVE AND RER DYNAMICS ASSOCIATED WITH THE CURVED JET STREAK WERE SUPPORTING ISO-SCT SHRA ACROSS THE SRN HALF OF THE CWA...MAINLY ALONG AND S OF THE BDRY. THESE FEATURES ARE EXPECTED TO MOVE E OF THE CWA BY DAYBREAK WITH PCPN DIMINISHING DUE TO SUBSIDENCE IN THE WAKE OF THE DEPARTING SHORTWAVE AND DRIER AIR FILTERING IN TO THE REGION AS A SFC HIGH SINKS SWD. HOWEVER...THE BDRY WILL STILL BE PRESENT /ALBEIT SLOWLY SINKING SWD/ ACROSS PART OF THE AREA THROUGH THE AFTN HOURS...AND ANOTHER SHORTWAVE WAS LOCATED UPSTREAM AT 07Z NEAR THE KS/CO BORDER. DESPITE THE DRIER AIR FILTERING IN FROM THE NORTH...MODELS DO SHOW SOME 300-250MB DIVERGENCE ACROSS THE SRN CWA DURING THE DAY AND WHEN COMBINED WITH THE CO/KS SHORTWAVE THERE MAY BE ENOUGH SUPPORT FOR ISO-SCT SHRA THIS AFTN INVOF THE BDRY. KANOFSKY && .LONG TERM... ISSUED AT 300 AM CDT FRI SEP 28 2012 (TONIGHT - TUESDAY) ZONAL FLOW ALOFT THAT HAS GIVEN US A PROLONGED PERIOD OF UNSETTLED WX THIS PAST WEEK WILL TRANSITION TO NW TO N FLOW THAT SHOULD GIVE US A QUIETER PERIOD FOR A BIT. THIS CHANGE IN FLOW WILL INITIALLY BE HELPED OUT BY A POLAR VORTEX DIGGING INTO THE GRTLKS REGION THIS WEEKEND AND LATER BY A TROF THAT DIGS INTO THE CNTRL AND S CNTRL CONUS EARLY NEXT WEEK...WITH BOTH OF THESE FEATURES EXPECTED TO BE FAR ENOUGH AWAY TO HAVE LITTLE IMPACT. THE SFC IS EXPECTED TO HAVE A WEAK RIDGE PREVAILING FOR MUCH OF THIS PERIOD...ALTHOUGH A TROF WILL TAKE A SWIPE MAINLY AT THE IL SIDE ON SATURDAY NIGHT AND SUNDAY. BELOW NORMAL PWATS FOR THIS WEEKEND...A STABLE ATMOSPHERE...AND MOST IMPORTANTLY...LIFTING MECHANISMS TOO WEAK...SHOULD PRECLUDE ANY PCPN DEVELOPMENT THIS WEEKEND. NEAR AVERAGE TEMPS FOR LATE SEPTEMBER ARE EXPECTED...WHICH FAVOR THE MAV MOS NUMBERS WHICH IN MOST CASES ARE RUNNING A BIT LOWER THAN THE MET MOS. UP UNTIL THIS POINT THERE IS GOOD AGREEMENT BETWEEN THE MODELS. WE START TO SEE SOME DISAGREEMENT BEGINNING MONDAY WHERE THE ECMWF DRAGS A CDFNT THRU WHEREAS THE GFS KEEPS IT WEST OF THE FA WHERE IT THEN DISSIPATES IT AND RE-ESTABLISHES THE RIDGE. IT APPEARS WITH RESPECT TO THE BOTTOM LINE...THIS IS A MINOR QUIBBLE AS THE ECMWF STRUGGLES TO BRING ANY MOISTURE UP IN TIME FOR WHEN IT BRINGS THE CDFNT THRU...AND IF THIS DOES HAPPEN...SHOULD GO THRU DRY AS A SYSTEM FURTHER TO THE SE WILL STEAL THE SHOW AND HOG THE SENSIBLE WX. WILL NEED TO WATCH EXACTLY WHERE THIS SERN CONUS SYSTEM GOES AS IT COULD EDGE SOME PARTS OF SERN MO AND SRN IL ON MONDAY. TEMPS COULD BE A BIGGER SOURCE OF ERROR HERE...NAMELY IF THE FRONT ACTUALLY GOES THRU OR NOT...BUT TEMPS AT OR A BIT ABOVE AVERAGE SEEM THE BETTER BET. (WEDNESDAY - THURSDAY) GFS AND ECMWF CONTINUE THEIR STANDOFF INTO THE MID AND LATER PARTS OF NEXT WEEK. THE ECMWF FEATURES ZONAL FLOW RETURNING BUT MORE IN THE FORM OF A PLATEAUED OUT BUILDING RIDGE FROM THE SW WHILE THE GFS MAINTAINS A TROF OVER THE LOWER MS VALLEY WHICH THEN LIFTS NEWD INTO THE LOWER OH VALLEY AS IT GETS ABSORBED. EITHER WAY...BOTH ARE TAKING ANOTHER...STRONGER...CDFNT THRU THE AREA DURING THIS TIME BUT THE DIFFS IN FLOW ALOFT WILL MAKE FOR A TIMING QUANDARY WITH THE FRONT BY AS MUCH AS 24HRS. THE GFS TAKES THE CDFNT THRU WEDNESDAY WHILE THE ECMWF DOESN/T UNTIL THURSDAY. BUT ONCE AGAIN...MOISTURE RETURN FROM THE GULF IS EFFECTIVELY BLOCKED AND WILL MAKE FOR LIMITED AMOUNTS TO WORK WITH. VERY QUESTIONABLE WHETHER OR NOT FRONT CAN GENERATE PCPN HERE BUT IF STRENGTH OF COLD AIR BEHIND IS SUFFICIENT...IT MAY. ABOVE AVERAGE TEMPS TO CONTINUE AHEAD OF FRONT. TES && .AVIATION... ISSUED AT 615 AM CDT FRI SEP 28 2012 ISO-SCT SHRA INVOF KCOU AND THE STL METRO AREA TAF SITES ARE EXPECTED TO CONTINUE FOR A FEW MORE HOURS UNTIL A SLOWLY MOVING FRONT FINALLY SINKS SOUTH OF THE TERMINALS. ISO-SCT PCPN WILL STILL BE POSSIBLE ALONG AND SOUTH OF THE FRONT TODAY BUT THIS SHOULD BE LIMITED TO AREAS SOUTH OF THE TAF SITES. MVFR CIGS ARE EXPECTED TO IMPROVE THIS MORNING DUE TO A COMBINATION OF DIURNAL MIXING...DRIER AIR NORTH OF THE FRONT...AND THE DEPARTURE OF THE FRONTAL BDRY. SPECIFICS FOR KSTL...SCT SHRA INVOF KSTL ARE EXPECTED FOR A FEW MORE HOURS UNTIL A SLOWLY MOVING FRONT SINKS SOUTH OF THE TERMINAL. MVFR CIGS ARE EXPECTED TO IMPROVE TO VFR LATER THIS MORNING ONCE THE BDRY SINKS FARTHER SOUTH OF KSTL. KANOFSKY && .PRELIMINARY POINT TEMPS/POPS... ST LOUIS 71 52 75 56 / 10 0 0 0 QUINCY 70 47 76 50 / 5 0 0 0 COLUMBIA 72 48 75 51 / 10 0 0 0 JEFFERSON CITY 72 49 74 51 / 20 5 0 0 SALEM 71 48 72 50 / 10 0 0 5 FARMINGTON 71 50 73 50 / 20 5 0 0 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
315 AM CDT FRI SEP 28 2012 .SHORT TERM... ISSUED AT 313 AM CDT FRI SEP 28 2012 (TODAY) THE PRIMARY FCST ISSUE FOR THIS FCST PD IS DETERMINING WHICH PARTS OF THE CWA ARE MOST LIKELY TO RECEIVE PCPN THROUGH 00Z. 07Z METARS AND MSAS SATURATED EQUIVALENT POTENTIAL TEMPERATURE FIELDS DEPICTED AN E-W ORIENTED BDRY BISECTING THE CWA. ALOFT...A SHORTWAVE TROF WAS LOCATED OVER CENTRAL AND WRN MO PER WATER VAPOR SATELLITE IMAGERY ALONG WITH AN ANTICYCLONICALLY CURVED JET STREAK AT H25 OVER CENTRAL IL NOTED ON THE LATEST RUC ANALYSIS AND SUPPORTED BY AREA VWP/PROFILER OBS. LARGE SCALE LIFT AHEAD OF THIS SHORTWAVE AND RER DYNAMICS ASSOCIATED WITH THE CURVED JET STREAK WERE SUPPORTING ISO-SCT SHRA ACROSS THE SRN HALF OF THE CWA...MAINLY ALONG AND S OF THE BDRY. THESE FEATURES ARE EXPECTED TO MOVE E OF THE CWA BY DAYBREAK WITH PCPN DIMINISHING DUE TO SUBSIDENCE IN THE WAKE OF THE DEPARTING SHORTWAVE AND DRIER AIR FILTERING IN TO THE REGION AS A SFC HIGH SINKS SWD. HOWEVER...THE BDRY WILL STILL BE PRESENT /ALBEIT SLOWLY SINKING SWD/ ACROSS PART OF THE AREA THROUGH THE AFTN HOURS...AND ANOTHER SHORTWAVE WAS LOCATED UPSTREAM AT 07Z NEAR THE KS/CO BORDER. DESPITE THE DRIER AIR FILTERING IN FROM THE NORTH...MODELS DO SHOW SOME 300-250MB DIVERGENCE ACROSS THE SRN CWA DURING THE DAY AND WHEN COMBINED WITH THE CO/KS SHORTWAVE THERE MAY BE ENOUGH SUPPORT FOR ISO-SCT SHRA THIS AFTN INVOF THE BDRY. KANOFSKY && .LONG TERM... ISSUED AT 300 AM CDT FRI SEP 28 2012 (TONIGHT - TUESDAY) ZONAL FLOW ALOFT THAT HAS GIVEN US A PROLONGED PERIOD OF UNSETTLED WX THIS PAST WEEK WILL TRANSITION TO NW TO N FLOW THAT SHOULD GIVE US A QUIETER PERIOD FOR A BIT. THIS CHANGE IN FLOW WILL INITIALLY BE HELPED OUT BY A POLAR VORTEX DIGGING INTO THE GRTLKS REGION THIS WEEKEND AND LATER BY A TROF THAT DIGS INTO THE CNTRL AND S CNTRL CONUS EARLY NEXT WEEK...WITH BOTH OF THESE FEATURES EXPECTED TO BE FAR ENOUGH AWAY TO HAVE LITTLE IMPACT. THE SFC IS EXPECTED TO HAVE A WEAK RIDGE PREVAILING FOR MUCH OF THIS PERIOD...ALTHOUGH A TROF WILL TAKE A SWIPE MAINLY AT THE IL SIDE ON SATURDAY NIGHT AND SUNDAY. BELOW NORMAL PWATS FOR THIS WEEKEND...A STABLE ATMOSPHERE...AND MOST IMPORTANTLY...LIFTING MECHANISMS TOO WEAK...SHOULD PRECLUDE ANY PCPN DEVELOPMENT THIS WEEKEND. NEAR AVERAGE TEMPS FOR LATE SEPTEMBER ARE EXPECTED...WHICH FAVOR THE MAV MOS NUMBERS WHICH IN MOST CASES ARE RUNNING A BIT LOWER THAN THE MET MOS. UP UNTIL THIS POINT THERE IS GOOD AGREEMENT BETWEEN THE MODELS. WE START TO SEE SOME DISAGREEMENT BEGINNING MONDAY WHERE THE ECMWF DRAGS A CDFNT THRU WHEREAS THE GFS KEEPS IT WEST OF THE FA WHERE IT THEN DISSIPATES IT AND RE-ESTABLISHES THE RIDGE. IT APPEARS WITH RESPECT TO THE BOTTOM LINE...THIS IS A MINOR QUIBBLE AS THE ECMWF STRUGGLES TO BRING ANY MOISTURE UP IN TIME FOR WHEN IT BRINGS THE CDFNT THRU...AND IF THIS DOES HAPPEN...SHOULD GO THRU DRY AS A SYSTEM FURTHER TO THE SE WILL STEAL THE SHOW AND HOG THE SENSIBLE WX. WILL NEED TO WATCH EXACTLY WHERE THIS SERN CONUS SYSTEM GOES AS IT COULD EDGE SOME PARTS OF SERN MO AND SRN IL ON MONDAY. TEMPS COULD BE A BIGGER SOURCE OF ERROR HERE...NAMELY IF THE FRONT ACTUALLY GOES THRU OR NOT...BUT TEMPS AT OR A BIT ABOVE AVERAGE SEEM THE BETTER BET. (WEDNESDAY - THURSDAY) GFS AND ECMWF CONTINUE THEIR STANDOFF INTO THE MID AND LATER PARTS OF NEXT WEEK. THE ECMWF FEATURES ZONAL FLOW RETURNING BUT MORE IN THE FORM OF A PLATEAUED OUT BUILDING RIDGE FROM THE SW WHILE THE GFS MAINTAINS A TROF OVER THE LOWER MS VALLEY WHICH THEN LIFTS NEWD INTO THE LOWER OH VALLEY AS IT GETS ABSORBED. EITHER WAY...BOTH ARE TAKING ANOTHER...STRONGER...CDFNT THRU THE AREA DURING THIS TIME BUT THE DIFFS IN FLOW ALOFT WILL MAKE FOR A TIMING QUANDARY WITH THE FRONT BY AS MUCH AS 24HRS. THE GFS TAKES THE CDFNT THRU WEDNESDAY WHILE THE ECMWF DOESN/T UNTIL THURSDAY. BUT ONCE AGAIN...MOISTURE RETURN FROM THE GULF IS EFFECTIVELY BLOCKED AND WILL MAKE FOR LIMITED AMOUNTS TO WORK WITH. VERY QUESTIONABLE WHETHER OR NOT FRONT CAN GENERATE PCPN HERE BUT IF STRENGTH OF COLD AIR BEHIND IS SUFFUCIENT...IT MAY. ABOVE AVERAGE TEMPS TO CONTINUE AHEAD OF FRONT. TES && .AVIATION... ISSUED AT 1152 PM CDT THU SEP 27 2012 HAVE ADDED VCSH AT KCOU AND THE ST. LOUIS METRO TAFS OVER THE NEXT 6 HOURS AS SCATTERED -RA HAS DEVELOPED OVER WRN MO AND WILL MOVE EAST OVERNIGHT. OTHERWISE...NOT CERTAIN IF CIGS WILL FALL INTO THE MVFR RANGE THROUGH 14Z...SO HAVE CIGS IN THE BKN035-040 RANGE. AFTER 15Z...EXPECT DRY AND VFR CONDITIONS THE REST OF THE PERIOD. SPECIFICS FOR KSTL...HAVE ADDED VCSH FROM 08-11Z TO REFLECT RECENT DEVELOPMENT OF -RA OVER CNTRL/WRN MO. THERE IS STILL SOME POSSIBILITY THAT CIGS WILL FALL INTO THE MVFR RANGE OVERNIGHT...BUT WITH PERSISTENT 10-15KT WINDS BETWEEN 1-3K FT NOTED ON THE KLSX AND TSTL WIND PROFILES THAT WILL IS BRINGING DRY AIR INTO THE REGION...DO NOT FEEL CONFIDENT ENOUGH AT THIS POINT TO INCLUDE IN A PREDOMINANT GROUP IN THE TAF. OTHERWISE...EXPECT DRY AND VFR CONDITIONS TO RETURN TO THE AREA BY MID-MORNING FRIDAY. BRITT && .PRELIMINARY POINT TEMPS/POPS... ST LOUIS 75 52 75 56 / 10 0 0 0 QUINCY 71 47 76 50 / 5 0 0 0 COLUMBIA 73 48 75 51 / 10 0 0 0 JEFFERSON CITY 73 49 74 51 / 20 5 0 0 SALEM 72 48 72 50 / 10 0 0 5 FARMINGTON 72 50 73 50 / 20 5 0 0 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1152 PM CDT THU SEP 27 2012 .UPDATE... ISSUED AT 801 PM CDT THU SEP 27 2012 HAVE REDUCED POPS THRU MUCH OF THE NIGHT BASED ON LATEST RADAR TRENDS AND HRRR DATA. STILL BELIEVE AN INCREASE IN COVERAGE OF PRECIP WILL OCCUR...BUT EXPECT IT TO BE LATE TONIGHT. S/W APPROACHING THE REGION SHUD HELP PROVIDE ENUF LIFT THAT ISOD TO SCT SHRA WILL DEVELOP ACROSS SRN MO. EXPECT PRECIP TO REMAIN ACROSS SRN HALF OF THE CWA CO-LOCATED WITH BETTER FORCING AND WHAT LITTLE INSTABILITY REMAINS. EXPECT CLOUDS TO REMAIN OVER MUCH OF THE CWA THRU MOST OF THE NIGHT. SOME QUESTION REMAINS ABOUT CLOUDS AS THE S/W MOVES THRU. IF ENUF CLEARING CAN OCCUR S OF THE FNT...DEVELOPMENT OF FG WILL BECOME A CONCERN ONCE AGAIN. WILL KEEP MENTION OF FG OUT OF FORECAST FOR NOW AND ADDRESS IF/WHEN NEEDED. TILLY && .SHORT TERM... ISSUED AT 311 PM CDT THU SEP 27 2012 SYNOPSIS WEAK ZONAL FLOW REMAINS IN CONTROL TODAY. AT THE SFC...A SLOW MOVING COLD FRONT CONTINUES STEADY PROGRESS SOUTH. THE BNDRY EXTENDS FROM AN AREA OF LOW PRESSURE IN OK...NE INTO CNTRL MO AND IL AND ON INTO THE OH VLY. A WAVE ALONG THE FRONT IS PUSHING THRU SW MO AND SHOULD CONTINUE TO SLIDE EAST ALONG THE FRONT THRU THIS EVENING. DIURNAL SHRA HAVE ALREADY BEGUN TO FORM ACROSS NW AR AND S CNTRL MO IN ADVANCE OF THIS FEATURE. OTHER SHRAS HAVE FORMED ACROSS ERN KS AND WRN MO ON WHAT IS PROBABLY THE ACTUAL FRONT. TO THE NORTH...A WEAK AREA OF HIGH PRESSURE HAS CLEARED THE SKIES ACROSS NTRHN MO AND W CNTRL IL. (TONIGHT THROUGH SUNDAY) MAIN FOCUS FOR THIS PERIOD WILL BE POPS THRU TOMORROW. THE COLD FRONT THAT HAS BEEN TRUDGING THRU THE CWA FOR THE PAST COUPLE OF DAYS HAS FINALLY MADE IT TO I70 TODAY. SHRA/ISLD TSTMS WILL CONTINUE TO DOT THE STHRN FA THIS EVENING AND THRU THE OVERNIGHT HRS. A VORT MAX RIDING ENE ALONG THE FRONT WILL ENHANCE THE COVERAGE OF PRECIP THIS EVENING AND INTO THE EARLY OVERNIGHT HRS. THE NAM AND SUBSEQUENTLY THE LOCAL WRF APPEAR TO BE TOO STRONG WITH THIS ENERGY. CONSEQUENTLY...THEY BOTH DEPICT WIDESPREAD PRECIP SOUTH OF I70 THIS EVENING AND OVERNIGHT. I THINK THIS IS WAY OVERDONE AND THE COVERAGE WILL BE MORE OF A SCATTERED NATURE. THE FRONT SHOULD PUSH OUT OF THE AREA FRIDAY MORNING. THERE WILL STILL BE A CHANCE OF SHRAS ON FRIDAY ACROSS THE ERN OZARKS DUE TO THE PROXIMITY OF THE FRONT. THE WEAK HIGH WILL CONTINUE TO BUILD INTO THE AREA ON FRIDAY. ALOFT...A CLOSED LOW OVER JAMES BAY WILL DROP SSW TO LOWER MI BY SUNDAY MORNING. THIS WILL CAUSE HEIGHTS TO DROP THIS WEEKEND AND TEMPER THE MODERATION OF THE AIR MASS. 850 TEMPS WILL REMAIN IN THE UPPER SINGLE DIGITS TO THE LOWER TEENS THRU THE PERIOD...THOUGH THERE WILL BE A TIGHTER GRADIENT ON SUNDAY AS THE UPPER LOW MAKES IT/S CLOSEST APPROACH. A WEAK AREA OF LOW PRESSURE IS EXPECTED TO DVLP THIS WKND IN RESPONSE TO A SW WAVE ROTATING AROUND THE BACK SIDE OF THE CLOSED LOW. THE MAIN IMPACT OF THIS SYSTEM SHOULD BE A CHANGE IN THE WIND DIRECTION AS IT PASSES BY TO THE NE SATURDAY/NIGHT. WINDS SHOULD BECOME WESTERLY FOR A TIME ON SATURDAY AFTN. CLOUDS AND PRECIP CHANCES SHOULD KEEP TEMPS DOWN A BIT ON FRIDAY ACROSS THE ERN OZARKS...OTHERWISE EXPECT CLEAR/MOSTLY CLEAR SKIES WITH HIGHS IN THE 70S AND LOWS IN THE UPPER 40S/50S. WENT WITH A BLEND OF GUIDANCE FOR THE MOST PART WITH A FEW EXCEPTIONS. WENT WITH THE COOLER MAV GUIDANCE FOR HIGHS TOMORROW ACROSS THE ERN OZARKS DUE TO CLOUDS AND PRECIP POTENTIAL. USED THE WARMER MET GUIDANCE ACROSS THE ERN OZARKS TONIGHT FOR THE SAME REASON AS THE COOLER GUIDANCE FOR HIGHS ON FRIDAY. TRIED TO USE THE COOLER MAV MOS FOR LOWS OVER THE WKND. CLEAR SKIES...LIGHT WINDS AND LOW DPS SHOULD CREATE COOL OVERNIGHT LOWS. MILLER && .LONG TERM... ISSUED AT 311 PM CDT THU SEP 27 2012 (SUNDAY NIGHT THRU THURSDAY NIGHT) THIS APPEARS TO BE AN EXTENDED PERIOD OF TRANQUIL WEATHER FOR NEXT WEEK WITH DRY CONDITIONS AND HIGHS IN THE MID 70S TO LOW 80S AND LOWS IN THE 50S. THE CLOSED LOW OVER THE GRT LKS LIFTS NE ON MONDAY. IN IT/S WAKE IS A LW TROF THAT TRANSITIONS TO ZONAL FLOW BY MIDWEEK. THE MODELS ARE INDICATING THE BASE OF THE TROF TRIES TO CLOSE OFF...BUT THEIR SOLUTIONS VARY ON THE EVOLUTION OF THIS FEATURE. MODELS INDICATE A SURGE OF MOISTURE FROM THE GULF COAST INTO THE TN/OH VLYS TOWARDS THE END OF THE PERIOD AS THE REMNANTS OF THE TROF ARE ABSORBED INTO THE ZONAL FLOW. MOST OF THE PRECIP STAYS TO THE EAST ATTM...BUT SOMETHING TO BE WATCHED. MILLER && .AVIATION... ISSUED AT 1152 PM CDT THU SEP 27 2012 HAVE ADDED VCSH AT KCOU AND THE ST. LOUIS METRO TAFS OVER THE NEXT 6 HOURS AS SCATTERED -RA HAS DEVELOPED OVER WRN MO AND WILL MOVE EAST OVERNIGHT. OTHERWISE...NOT CERTAIN IF CIGS WILL FALL INTO THE MVFR RANGE THROUGH 14Z...SO HAVE CIGS IN THE BKN035-040 RANGE. AFTER 15Z...EXPECT DRY AND VFR CONDITIONS THE REST OF THE PERIOD. SPECIFICS FOR KSTL...HAVE ADDED VCSH FROM 08-11Z TO REFLECT RECENT DEVELOPMENT OF -RA OVER CNTRL/WRN MO. THERE IS STILL SOME POSSIBILITY THAT CIGS WILL FALL INTO THE MVFR RANGE OVERNIGHT...BUT WITH PERSISTENT 10-15KT WINDS BETWEEN 1-3K FT NOTED ON THE KLSX AND TSTL WIND PROFILES THAT WILL IS BRINGING DRY AIR INTO THE REGION...DO NOT FEEL CONFIDENT ENOUGH AT THIS POINT TO INCLUDE IN A PREDOMINANT GROUP IN THE TAF. OTHERWISE...EXPECT DRY AND VFR CONDITIONS TO RETURN TO THE AREA BY MID-MORNING FRIDAY. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
215 PM EDT FRI SEP 28 2012 .SYNOPSIS... ISOLATED TO SCATTERED SHOWERS WILL LINGER ACROSS THE REGION THIS AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN NEW ENGLAND. AN UPPER LEVEL DISTURBANCE WILL BRING UNSETTLED CONDITIONS TO THE REGION SUNDAY AND MONDAY. NEAR SEASONAL TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND...WITH TEMPERATURES MODERATING BY MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1130 AM UPDATE...SFC LOW PRES WAS LOCATED OVER NRN NEW JERSEY WITH ISOLATED TO SCATTERED SHOWERS BACK ACROSS CENTRAL NY AND NRN TIER OF PA WITH MORE WIDESPREAD ACTIVITY IN PIKE/SULLIVAN COUNTIES. ACTIVITY WILL ALL BECOME JUST ISOLATED TO SCATTERED DURING THE NEXT COUPLE OF HOURS AS SFC LOW TRACKS TOWARD LONG ISLAND. WILL CONTINUE WITH SLIGHT CHC/CHC POPS THROUGH LATE AFTERNOON WITH HIGHEST POPS NRN/ERN CWA IN AREA OF BETTER MOISTURE/FORCING. SATELLITE SHOWS OVERCAST SKIES BACK ACROSS LAKE ONTARIO AND EXPECT AREA TO REMAIN CLOUDY THROUGH MUCH OF THE AFTERNOON WITH SLOW IMPROVEMENT LATE DAY. BASED ON PERSISTENCE OF LOW CLOUDS LOWERED MAX TEMPS SEVERAL DEGREES. PREVIOUS DISC... 4 AM UPDATE... LARGE SCALE UL LOW LOCATED ACRS LABRADOR AND OVR HUDSON BAY. S/WV IS RIPPING THRU CNTRL PA...SPURRING SCTD SHOWERS ACRS NY/PA AND NJ AT THIS HOUR. ELONGATED SFC LOW EXTNDS ACRS THE SPINE OF THE APPS. GREATEST 3HR SFC PRESSURE FALLS LOCATED OVR ERN PA AND 00Z NAM/GFS TENDS TO AGREE ON THIS MVMNT THRU 12Z. HOW FAR NORTH THIS RAIN PROGRESSES ACRS THE CWA IS UP FOR DEBATE AND MODELS DIFFER ON HOW MUCH OF THE FA WL BE IMPACTED. NAM/GFS ARE FURTHEST TO THE NORTH WITH THIS PCPN. LATEST HRRR GUIDANCE KEEPS IT CONFINED FURTHER SOUTH...THEREFORE HV DROPPED POPS ACRS FAR NRN ZONES NORTH OF A PENN YAN TO SYR TO BOONVILLE LINE THRU 12Z. AS THE MRNG PROGRESSES AIR MASS WL BEGIN TO SATURATE DOWN WITH LKLY POPS THRU A GOOD PORTION OF THE AREA THRU THE MRNG HRS. FURTHER TO THE SOUTHEAST SIGNIFICANT WIND SHEAR WL BE PRESENT TWD DAYBREAK WITH NAM INDICATING CAPES ARND 200 J/KG AND GFS AT 0 THRU THE DAY TODAY. THUS HV ADDED IN SLGT CHC FOR THUNDER SOUTH OF THE I-84 CORRIDOR. AS FOR MAX TEMPS TDA...MOCLDY SKIES WL BE PRESENT THRU THE DAY WITH H8 TEMPS DROPPING TO BLO 10C. THUS HIGHS WL ONLY REACH TO NR 60F ACRS UPSTATE NY WITH WYOMING/LACKAWANNA VLYS TOPPING OUT IN THE MID-UPR 60S. AS LOPRES WORKS ITS WAY OFF TO THE NE PCPN WL COME TO AN END BY 00Z. TOTAL QPF AMNTS APPEAR TO BE ARND 1.00 INCH THRU 00Z TONIGHT ACRS THE WRN CATS AND POCONOS. RMNDR OF THE REGION WL SEE AMNTS ARND 0.50 INCHES. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... 4 AM UPDATE... RAIN WL COME TO AN END BY SAT MRNG WITH H8 CLD AIR ADVECTION WORKING INTO THE CWA. MIN TEMPS WL DIP INTO THE MID-40S AND POSSIBLY INTO THE U30S IN FAVORED LOW VLYS ACRS THE CNTRL SRN TIER WHERE CAA WL BE STRONGEST. H5 LOW WL DRIFT SOUTH OUT OF HUDSON BAY WITH ALL GUIDANCE (NAM/GFS/EC) DROPPING IT TO ONTARIO/QUEBEC BORDER BY 12Z SAT. AS UL LOW APPCHS ON SAT ISOLD SHRAS WL DVLP ACRS THE CWA. THIS UL LOPRES SYSTEM WL AFFECT CNTRL NY/NEPA THRU THE SHORT TERM. SFC LOW WL DVLP AND MV INTO THE REGION ALONG WITH PCPN BEGINNING ON SUNDAY. POPS INCRS FOR SUN AFTN AND INTO THE OVRNGT HRS...WITH LKLY POPS THRU 12Z MON. TEMPS DRG THE LATTER HALF OF THE WEEKEND WL AVG NR CLIMO. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS IN DECENT AGREEMENT WITH THE SETUP FOR MONDAY NIGHT. THERE WILL BE AN EJECTING 500MB CUTOFF LOW THAT SHOULD BE NORTH OF MAINE. THEY ALSO INDICATE THAT A 500MB LOW PRESSURE TROUGH WILL BE MOVING EASTWARDS ACROSS THE MISSISSIPPI VALLEY MONDAY NIGHT. AHEAD OF THIS TROUGH A SFC LOW AND AN AREA OF SHOWERS WILL MOVE NORTHWARD ALONG THE EASTERN UNITED STATES. SHOWERS WILL BE CLOSE TO THE SOUTHERN ZONES LATE MONDAY NIGHT. HAVE BUMPED POPS SLIGHTLY TO HAVE A MENTION OF SHOWERS IN NEPA. THE SOUTHERN TIER, AND CATSKILLS. FROM THERE, MODEL DIFFER SLIGHTLY. THE ECMWF SHOWS SHOWERS MAY TRY TO SLIDE OFF TO THE EAST, CLIPPING THE EASTERN ZONES, WHILE THE GFS HAS THE MAIN BATCH OF SHOWERS COMING RIGHT ACROSS THE ON TUESDAY. HAVE BUMPED POPS TO CHC FOR THESE AREAS AND SLIGHT CHC FOR THE REMAINDER OF THE CWA. BY WEDNESDAY MORNING, THE TROUGH CUTS OFF OVER TENNESSEE, BLOCKED BY A BUILDING BERMUDA HIGH. SEVERAL WAVES WILL RIDE OVER THE HIGH, WITH A MOIST RETURN FLOW OVER THE CWA. THIS COULD END UP KEEPING AT LEAST A SLIGHT CHC OF POPS IN THE FORECAST FOR MOST OF THE REMAINDER OF THE WEEK. MODELS BEGIN TO DIFFER GREATLY BY THE END OF NEXT WEEK. THE GFS HAS A VERY STRONG LOW PRESSURE SYSTEM OVER THE HUDSON BAY BY FRIDAY 06Z, WITH A COLD FRONT APPROACHING THE AREA FROM THE WEST. LOOKING AT THE ECMWF, THERE IS A SHORT WAVE AT 500MB WITH A SFC LOW DEEPENING AS IT MOVES ACROSS THE GREAT LAKES EASTWARD, ENDING UP JUST NORTH OF MAINE BY 06Z FRIDAY, KEEPING THE CWA DRY. GIVEN THESE DIFFERENCES, HAVE KEPT POPS OUT OF THE FORECAST FOR FRIDAY FOR NOW, AS THERE IS GREAT UNCERTAINTY ATTM. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... A VERY DIFFICULT AVIATION FORECAST AT BEST. AN UPPER LEVEL LOW PRESSURE SYSTEM IS DROPPING SOUTHWARDS TOWARDS THE FORECAST AREA. THE LOW, A WEAK SFC LOW, AND PLENTY OF SFC MOISTURE, HAVE KEPT A VERY LOW DECK OF CLOUDS ALONG WITH SOME LIGHT RAIN SHOWERS AND DRIZZLE AROUND THIS AFTERNOON. LOOKING AT THE MODELS, THIS LOW DECK SHOULD EVER SO SLOWLY BEGIN TO LIFT THIS AFTERNOON AND EVENING. HOWEVER, THIS MAY TAKE UNTIL EARLY TOMORROW MORNING BEFORE THEY FINALLY RISE ENOUGH TO GO EVEN MVFR. WITH THE LOW DECK, NOT EXPECTING MUCH IN THE WAY OF FOG, ALTHOUGH SOME SPOTS MAY STILL SEE FOG EITHER DEVELOP, OR REMAIN IN PLACE FOR NOW. HAVE PLAYED THE FORECAST CONSERVATIVELY FOR NOW, AS CIGS ARE NOT RISING MUCH AND RADAR CONTINUES TO SHOW LIGHT SHOWERS DEVELOPING AND MOVING ACROSS THE AREA. WINDS LOOK TO BE THE LEAST CONCERN THROUGH THE TAF PERIOD AS THEY WILL RANGE FROM LIGHT AND VARIABLE TONIGHT AND BECOMING NW A BETWEEN 5 AND 10 KTS TOMORROW MORNING. OUTLOOK... SAT...GENERALLY VFR. SUN THROUGH WED...VFR WITH MVFR IN SHOWERS POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN/RRM NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM...SLI AVIATION...SLI
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1143 AM EDT FRI SEP 28 2012 .SYNOPSIS... ISOLATED TO SCATTERED SHOWERS WILL LINGER ACROSS THE REGION THIS AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN NEW ENGLAND. AN UPPER LEVEL DISTURBANCE WILL BRING UNSETTLED CONDITIONS TO THE REGION SUNDAY AND MONDAY. NEAR SEASONAL TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND...WITH TEMPERATURES MODERATING BY MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1130 AM UPDATE...SFC LOW PRES WAS LOCATED OVER NRN NEW JERSEY WITH ISOLATED TO SCATTERED SHOWERS BACK ACROSS CENTRAL NY AND NRN TIER OF PA WITH MORE WIDESPREAD ACTIVITY IN PIKE/SULLIVAN COUNTIES. ACTIVITY WILL ALL BECOME JUST ISOLATED TO SCATTERED DURING THE NEXT COUPLE OF HOURS AS SFC LOW TRACKS TOWARD LONG ISLAND. WILL CONTINUE WITH SLIGHT CHC/CHC POPS THROUGH LATE AFTERNOON WITH HIGHEST POPS NRN/ERN CWA IN AREA OF BETTER MOISTURE/FORCING. SATELLITE SHOWS OVERCAST SKIES BACK ACROSS LAKE ONTARIO AND EXPECT AREA TO REMAIN CLOUDY THROUGH MUCH OF THE AFTERNOON WITH SLOW IMPROVEMENT LATE DAY. BASED ON PERSISTENCE OF LOW CLOUDS LOWERED MAX TEMPS SEVERAL DEGREES. PREVIOUS DISC... 4 AM UPDATE... LARGE SCALE UL LOW LOCATED ACRS LABRADOR AND OVR HUDSON BAY. S/WV IS RIPPING THRU CNTRL PA...SPURRING SCTD SHOWERS ACRS NY/PA AND NJ AT THIS HOUR. ELONGATED SFC LOW EXTNDS ACRS THE SPINE OF THE APPS. GREATEST 3HR SFC PRESSURE FALLS LOCATED OVR ERN PA AND 00Z NAM/GFS TENDS TO AGREE ON THIS MVMNT THRU 12Z. HOW FAR NORTH THIS RAIN PROGRESSES ACRS THE CWA IS UP FOR DEBATE AND MODELS DIFFER ON HOW MUCH OF THE FA WL BE IMPACTED. NAM/GFS ARE FURTHEST TO THE NORTH WITH THIS PCPN. LATEST HRRR GUIDANCE KEEPS IT CONFINED FURTHER SOUTH...THEREFORE HV DROPPED POPS ACRS FAR NRN ZONES NORTH OF A PENN YAN TO SYR TO BOONVILLE LINE THRU 12Z. AS THE MRNG PROGRESSES AIRMASS WL BEGIN TO SATURATE DOWN WITH LKLY POPS THRU A GOOD PORTION OF THE AREA THRU THE MRNG HRS. FURTHER TO THE SOUTHEAST SIGNIFICANT WIND SHEAR WL BE PRESENT TWD DAYBREAK WITH NAM INDICATING CAPES ARND 200 J/KG AND GFS AT 0 THRU THE DAY TODAY. THUS HV ADDED IN SLGT CHC FOR THUNDER SOUTH OF THE I-84 CORRIDOR. AS FOR MAX TEMPS TDA...MOCLDY SKIES WL BE PRESENT THRU THE DAY WITH H8 TEMPS DROPPING TO BLO 10C. THUS HIGHS WL ONLY REACH TO NR 60F ACRS UPSTATE NY WITH WYOMING/LACKAWANNA VLYS TOPPING OUT IN THE MID-UPR 60S. AS LOPRES WORKS ITS WAY OFF TO THE NE PCPN WL COME TO AN END BY 00Z. TOTAL QPF AMNTS APPEAR TO BE ARND 1.00 INCH THRU 00Z TONIGHT ACRS THE WRN CATS AND POCONOS. RMNDR OF THE REGION WL SEE AMNTS ARND 0.50 INCHES. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... 4 AM UPDATE... RAIN WL COME TO AN END BY SAT MRNG WITH H8 CLD AIR ADVECTION WORKING INTO THE CWA. MIN TEMPS WL DIP INTO THE MID-40S AND POSSIBLY INTO THE U30S IN FAVORED LOW VLYS ACRS THE CNTRL SRN TIER WHERE CAA WL BE STRONGEST. H5 LOW WL DRIFT SOUTH OUT OF HUDSON BAY WITH ALL GUIDANCE (NAM/GFS/EC) DROPPING IT TO ONTARIO/QUEBEC BORDER BY 12Z SAT. AS UL LOW APPCHS ON SAT ISOLD SHRAS WL DVLP ACRS THE CWA. THIS UL LOPRES SYSTEM WL AFFECT CNTRL NY/NEPA THRU THE SHORT TERM. SFC LOW WL DVLP AND MV INTO THE REGION ALONG WITH PCPN BEGINNING ON SUNDAY. POPS INCRS FOR SUN AFTN AND INTO THE OVRNGT HRS...WITH LKLY POPS THRU 12Z MON. TEMPS DRG THE LATTER HALF OF THE WEEKEND WL AVG NR CLIMO. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 320 AM UPDATE... DRY PERIOD EXPECTED EARLY NEXT WEEK FOLLOWING DEPARTURE OF THIS WEEKEND/S UPPER LOW. SOME QUESTIONS STILL REMAIN WITH RESPECT TO POSSIBLE COLD FRONT WHICH IS ADVERTISED BY THE GFS TO PASS WED AFTERNOON EVENING. THIS SOLUTION HAS VERY LITTLE SUPPORT FROM THE 00Z ECMWF WHICH TAKES A SFC LOW UP THE MID-ATLANTIC COAST DURING THIS TIME FRAME. THE ECMWF HAS BEEN ADVERTISING THIS IN RECENT RUNS AND BASED ON THIS...HAVE ELECTED TO INCREASE POPS BOTH TUE AND TUE NGT. FOLLOWING THIS SYSTEM/S DEPARTURE...DRIER WX LOOKS TO PREVAIL THROUGH THE DURATION OF THE EXTENDED PERIOD WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPS. PREVIOUS LONG TERM DISCUSSION... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... MAIN BATCH OF RAIN QUICKLY EXITING TOWARDS EASTERN NY THIS MORNING. MEANWHILE...NEW SCT SHWR ACTIVITY DEVELOPING ACROSS NORTH-CENTRAL PA AND WESTERN NY AS NEXT UPPER WAVE APPROACHES. HAVE INCLUDED TEMPO GROUPS AT ALL TERMINALS WITH THE EXCEPTION OF SYR AND RME FOR LIGHT SHRA ACTIVITY THROUGH 16Z. IFR CONDITIONS EXPECTED TO PERSIST AT BGM THROUGH THE MORNING WITH MVFR CONDITIONS LIKELY ELSEWHERE AS INITIAL WAVE EXITS TO THE NORTHEAST. IFR CIGS ALSO POSSIBLE AT ELM FOR A FEW HRS BEFORE CIGS START TO RISE LATER THIS MORNING. MAIN QUESTIONS LATER ONE HINGE UPON WHEN/IF CONDITIONS BEGIN TO CLEAR LATER ON. FOR NOW WILL SUGGEST BKN-OVC CIGS THROUGH LATE AFTERNOON WITH POTENTIAL BREAKS THEREAFTER. THE NAM SUGGESTS THE POSSIBILITY OF A DEVELOPING LAKE RESPONSE LATER TONIGHT WHICH MAY IMPACT SYR. FOR NOW WILL HIGHLIGHT A BKN MVFR MENTION AFTER 06Z. OUTLOOK... SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN/RRM NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM...CMG/RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
659 AM EDT FRI SEP 28 2012 .SYNOPSIS... SHOWERS WILL CONTINUE OFF AND ON ACROSS CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA TODAY. AS LOW PRESSURE EXITS THE AREA TO THE NORTHEAST TONIGHT RAIN WILL COME TO AN END. AN UPPER LEVEL DISTURBANCE WILL BRING UNSETTLED CONDITIONS TO THE REGION SUNDAY AND MONDAY. NEAR SEASONAL TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND...WITH TEMPERATURES MODERATING BY MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4 AM UPDATE... LARGE SCALE UL LOW LOCATED ACRS LABRADOR AND OVR HUDSON BAY. S/WV IS RIPPING THRU CNTRL PA...SPURRING SCTD SHOWERS ACRS NY/PA AND NJ AT THIS HOUR. ELONGATED SFC LOW EXTNDS ACRS THE SPINE OF THE APPS. GREATEST 3HR SFC PRESSURE FALLS LOCATED OVR ERN PA AND 00Z NAM/GFS TENDS TO AGREE ON THIS MVMNT THRU 12Z. HOW FAR NORTH THIS RAIN PROGRESSES ACRS THE CWA IS UP FOR DEBATE AND MODELS DIFFER ON HOW MUCH OF THE FA WL BE IMPACTED. NAM/GFS ARE FURTHEST TO THE NORTH WITH THIS PCPN. LATEST HRRR GUIDANCE KEEPS IT CONFINED FURTHER SOUTH...THEREFORE HV DROPPED POPS ACRS FAR NRN ZONES NORTH OF A PENN YAN TO SYR TO BOONVILLE LINE THRU 12Z. AS THE MRNG PROGRESSES AIRMASS WL BEGIN TO SATURATE DOWN WITH LKLY POPS THRU A GOOD PORTION OF THE AREA THRU THE MRNG HRS. FURTHER TO THE SOUTHEAST SIGNIFICANT WIND SHEAR WL BE PRESENT TWD DAYBREAK WITH NAM INDICATING CAPES ARND 200 J/KG AND GFS AT 0 THRU THE DAY TODAY. THUS HV ADDED IN SLGT CHC FOR THUNDER SOUTH OF THE I-84 CORRIDOR. AS FOR MAX TEMPS TDA...MOCLDY SKIES WL BE PRESENT THRU THE DAY WITH H8 TEMPS DROPPING TO BLO 10C. THUS HIGHS WL ONLY REACH TO NR 60F ACRS UPSTATE NY WITH WYOMING/LACKAWANNA VLYS TOPPING OUT IN THE MID-UPR 60S. AS LOPRES WORKS ITS WAY OFF TO THE NE PCPN WL COME TO AN END BY 00Z. TOTAL QPF AMNTS APPEAR TO BE ARND 1.00 INCH THRU 00Z TONIGHT ACRS THE WRN CATS AND POCONOS. RMNDR OF THE REGION WL SEE AMNTS ARND 0.50 INCHES. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... 4 AM UPDATE... RAIN WL COME TO AN END BY SAT MRNG WITH H8 CLD AIR ADVECTION WORKING INTO THE CWA. MIN TEMPS WL DIP INTO THE MID-40S AND POSSIBLY INTO THE U30S IN FAVORED LOW VLYS ACRS THE CNTRL SRN TIER WHERE CAA WL BE STRONGEST. H5 LOW WL DRIFT SOUTH OUT OF HUDSON BAY WITH ALL GUIDANCE (NAM/GFS/EC) DROPPING IT TO ONTARIO/QUEBEC BORDER BY 12Z SAT. AS UL LOW APPCHS ON SAT ISOLD SHRAS WL DVLP ACRS THE CWA. THIS UL LOPRES SYSTEM WL AFFECT CNTRL NY/NEPA THRU THE SHORT TERM. SFC LOW WL DVLP AND MV INTO THE REGION ALONG WITH PCPN BEGINNING ON SUNDAY. POPS INCRS FOR SUN AFTN AND INTO THE OVRNGT HRS...WITH LKLY POPS THRU 12Z MON. TEMPS DRG THE LATTER HALF OF THE WEEKEND WL AVG NR CLIMO. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 320 AM UPDATE... DRY PERIOD EXPECTED EARLY NEXT WEEK FOLLOWING DEPARTURE OF THIS WEEKEND/S UPPER LOW. SOME QUESTIONS STILL REMAIN WITH RESPECT TO POSSIBLE COLD FRONT WHICH IS ADVERTISED BY THE GFS TO PASS WED AFTERNOON EVENING. THIS SOLUTION HAS VERY LITTLE SUPPORT FROM THE 00Z ECMWF WHICH TAKES A SFC LOW UP THE MID-ATLANTIC COAST DURING THIS TIME FRAME. THE ECMWF HAS BEEN ADVERTISING THIS IN RECENT RUNS AND BASED ON THIS...HAVE ELECTED TO INCREASE POPS BOTH TUE AND TUE NGT. FOLLOWING THIS SYSTEM/S DEPARTURE...DRIER WX LOOKS TO PREVAIL THROUGH THE DURATION OF THE EXTENDED PERIOD WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPS. PREVIOUS LONG TERM DISCUSSION... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... MAIN BATCH OF RAIN QUICKLY EXITING TOWARDS EASTERN NY THIS MORNING. MEANWHILE...NEW SCT SHWR ACTIVITY DEVELOPING ACROSS NORTH-CENTRAL PA AND WESTERN NY AS NEXT UPPER WAVE APPROACHES. HAVE INCLUDED TEMPO GROUPS AT ALL TERMINALS WITH THE EXCEPTION OF SYR AND RME FOR LIGHT SHRA ACTIVITY THROUGH 16Z. IFR CONDITIONS EXPECTED TO PERSIST AT BGM THROUGH THE MORNING WITH MVFR CONDITIONS LIKELY ELSEWHERE AS INITIAL WAVE EXITS TO THE NORTHEAST. IFR CIGS ALSO POSSIBLE AT ELM FOR A FEW HRS BEFORE CIGS START TO RISE LATER THIS MORNING. MAIN QUESTIONS LATER ONE HINGE UPON WHEN/IF CONDITIONS BEGIN TO CLEAR LATER ON. FOR NOW WILL SUGGEST BKN-OVC CIGS THROUGH LATE AFTERNOON WITH POTENTIAL BREAKS THEREAFTER. THE NAM SUGGESTS THE POSSIBILITY OF A DEVELOPING LAKE RESPONSE LATER TONIGHT WHICH MAY IMPACT SYR. FOR NOW WILL HIGHLIGHT A BKN MVFR MENTION AFTER 06Z. OUTLOOK... SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...CMG/RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
358 AM EDT FRI SEP 28 2012 .SYNOPSIS... SHOWERS WILL CONTINUE OFF AND ON ACROSS CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA TODAY. AS LOW PRESSURE EXITS THE AREA TO THE NORTHEAST TONIGHT RAIN WILL COME TO AN END. AN UPPER LEVEL DISTURBANCE WILL BRING UNSETTLED CONDITIONS TO THE REGION SUNDAY AND MONDAY. NEAR SEASONAL TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND...WITH TEMPERATURES MODERATING BY MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4 AM UPDATE... LARGE SCALE UL LOW LOCATED ACRS LABRADOR AND OVR HUDSON BAY. S/WV IS RIPPING THRU CNTRL PA...SPURRING SCTD SHOWERS ACRS NY/PA AND NJ AT THIS HOUR. ELONGATED SFC LOW EXTNDS ACRS THE SPINE OF THE APPS. GREATEST 3HR SFC PRESSURE FALLS LOCATED OVR ERN PA AND 00Z NAM/GFS TENDS TO AGREE ON THIS MVMNT THRU 12Z. HOW FAR NORTH THIS RAIN PROGRESSES ACRS THE CWA IS UP FOR DEBATE AND MODELS DIFFER ON HOW MUCH OF THE FA WL BE IMPACTED. NAM/GFS ARE FURTHEST TO THE NORTH WITH THIS PCPN. LATEST HRRR GUIDANCE KEEPS IT CONFINED FURTHER SOUTH...THEREFORE HV DROPPED POPS ACRS FAR NRN ZONES NORTH OF A PENN YAN TO SYR TO BOONVILLE LINE THRU 12Z. AS THE MRNG PROGRESSES AIRMASS WL BEGIN TO SATURATE DOWN WITH LKLY POPS THRU A GOOD PORTION OF THE AREA THRU THE MRNG HRS. FURTHER TO THE SOUTHEAST SIGNIFICANT WIND SHEAR WL BE PRESENT TWD DAYBREAK WITH NAM INDICATING CAPES ARND 200 J/KG AND GFS AT 0 THRU THE DAY TODAY. THUS HV ADDED IN SLGT CHC FOR THUNDER SOUTH OF THE I-84 CORRIDOR. AS FOR MAX TEMPS TDA...MOCLDY SKIES WL BE PRESENT THRU THE DAY WITH H8 TEMPS DROPPING TO BLO 10C. THUS HIGHS WL ONLY REACH TO NR 60F ACRS UPSTATE NY WITH WYOMING/LACKAWANNA VLYS TOPPING OUT IN THE MID-UPR 60S. AS LOPRES WORKS ITS WAY OFF TO THE NE PCPN WL COME TO AN END BY 00Z. TOTAL QPF AMNTS APPEAR TO BE ARND 1.00 INCH THRU 00Z TONIGHT ACRS THE WRN CATS AND POCONOS. RMNDR OF THE REGION WL SEE AMNTS ARND 0.50 INCHES. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... 4 AM UPDATE... RAIN WL COME TO AN END BY SAT MRNG WITH H8 CLD AIR ADVECTION WORKING INTO THE CWA. MIN TEMPS WL DIP INTO THE MID-40S AND POSSIBLY INTO THE U30S IN FAVORED LOW VLYS ACRS THE CNTRL SRN TIER WHERE CAA WL BE STRONGEST. H5 LOW WL DRIFT SOUTH OUT OF HUDSON BAY WITH ALL GUIDANCE (NAM/GFS/EC) DROPPING IT TO ONTARIO/QUEBEC BORDER BY 12Z SAT. AS UL LOW APPCHS ON SAT ISOLD SHRAS WL DVLP ACRS THE CWA. THIS UL LOPRES SYSTEM WL AFFECT CNTRL NY/NEPA THRU THE SHORT TERM. SFC LOW WL DVLP AND MV INTO THE REGION ALONG WITH PCPN BEGINNING ON SUNDAY. POPS INCRS FOR SUN AFTN AND INTO THE OVRNGT HRS...WITH LKLY POPS THRU 12Z MON. TEMPS DRG THE LATTER HALF OF THE WEEKEND WL AVG NR CLIMO. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 320 AM UPDATE... DRY PERIOD EXPECTED EARLY NEXT WEEK FOLLOWING DEPARTURE OF THIS WEEKEND/S UPPER LOW. SOME QUESTIONS STILL REMAIN WITH RESPECT TO POSSIBLE COLD FRONT WHICH IS ADVERTISED BY THE GFS TO PASS WED AFTERNOON EVENING. THIS SOLUTION HAS VERY LITTLE SUPPORT FROM THE 00Z ECMWF WHICH TAKES A SFC LOW UP THE MID-ATLANTIC COAST DURING THIS TIME FRAME. THE ECMWF HAS BEEN ADVERTISING THIS IN RECENT RUNS AND BASED ON THIS...HAVE ELECTED TO INCREASE POPS BOTH TUE AND TUE NGT. FOLLOWING THIS SYSTEM/S DEPARTURE...DRIER WX LOOKS TO PREVAIL THROUGH THE DURATION OF THE EXTENDED PERIOD WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPS. PREVIOUS LONG TERM DISCUSSION... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... LATEST RADAR TRENDS SHOWING MAIN RAIN SHIELD PUSHING THROUGH THE TWIN TIERS AND REMAINDER OF NE PA THIS HR. SO FAR CONDITIONS HAVE LARGELY REMAINED VFR...HOWEVER EXPECT CATEGORICAL DETERIORATION WITHIN THE NEXT FEW HRS FOR ALL SITES EXCEPT SYR AND RME WHERE RAIN SHIELD SHOULD REMAIN SOUTH. FOR NOW EXPECT IFR CONDITIONS ARE BGM AFTER 08Z...WITH ELM/ITH/AVP LARGELY EXPECTED TO REMAIN MVFR. CLOUDS WILL BE SLOW TO GO WITH MVFR CONDITIONS EXPECTED THROUGH EARLY TO MID AFTERNOON. BEYOND THIS...DRIER AIR WILL MOVE INTO THE REGION WHICH SHOULD RESULT IN GRADUAL IMPROVEMENT TOWARDS 00Z. LIGHT EASTERLY WINDS EARLY ON WILL GRADUALLY SHIFT TOWARDS THE NORTHWEST (5-10 KTS) BY AFTERNOON AS LOW EXITS TO THE EAST. OUTLOOK... SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...CMG/RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
322 AM EDT FRI SEP 28 2012 .SYNOPSIS... CONDITIONS WILL DETERIORATE QUICKLY TONIGHT, AS LOW PRESSURE TRACKS TOWARDS OUR AREA FROM OHIO. RAIN WILL MOSTLY FALL LATE TONIGHT AND FRIDAY MORNING BEFORE ENDING FRIDAY AFTERNOON. SATURDAY, WEAK HIGH PRESSURE WILL BRING MAINLY DRY WEATHER. UNSETTLED CONDITIONS WILL RETURN SUNDAY INTO MONDAY AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE NORTHEAST UNITED STATES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12 AM UPDATE.. QUICK UPDATE TO RMV POPS ACRS THE FAR NORTH FOR TONIGHT. RADAR POPUP SKEW-T ACRS THE NRN ZONES INDICATE DRY LAYER FM SFC-H7. 00Z RAOBS INDICATE SAT/D AIRMASS TO THE SOUTH AND DRY AIR TO THE NORTH. THIS APPEARS TO SUPPORT BUFKIT SNDGS AND 00Z NAM GUIDANCE INDICATES A SLOW SATURATION OF ATMOS AFT 12Z ACRS THE NORTH...THUS HV TRIMMED POPS BACK THRU 12Z. PREVIOUS AFD BELOW. 9 PM UPDATE... RAIN NOW MOVING INTO NEPA. FROM RADAR RETURNS BIGGEST IMPACT WILL REMAIN HERE FOR THE NEXT FEW HOURS...WITH VERY LIGHT SHOWERS JUST GETTING INTO THE SOUTHERN TIER OF NY...WITH DRY WEATHER NORTH OF HERE. 7 PM UPDATE... AN AREA OF LIGHT RAIN ACROSS CENTRAL PA CONTINUES TO SLOWLY LIFT NORTHEAST BUT IS HAVING SOME TROUBLE AT THE MOMENT AS HIGH PRESSURE OVER QUEBEC IS SLOW TO LOSE ITS GRIP ON OUR AREA. THIS IS MOST EVIDENT WITH A QUICK GLANCE AT SURFACE DEW POINTS...SHOWING LOW TO MID 40S ACROSS CNY...BUT CREEPING INTO THE MID 50S DOWN IN NEPA. AS OUR ATMOSPHERE CONTINUES TO MOISTEN UP AND WE BEGIN TO SEE A MID DECK AROUND 5KFT DEVELOP...SHOWERS ARE LIKELY IN NEPA BETWEEN 02Z AND 04Z...OR JUST A TAD SLOWER THAN THE PREVIOUS FORECAST. THE 18Z NAM...ALONG WITH THE HIGHER RESOLUTION MODELS OF THE ARW/NMM AND HRRR CONTINUE TO SUGGEST THAT IT WILL BE HARD FOR PRECIP TO MAKE IT MUCH FARTHER NORTH THAN THE NY/PA LINE THROUGH 06Z. IN FACT...THE BIGGEST ADJUSTMENT WITH THIS PACKAGE WAS DELAYING THE RAIN MUCH LONGER ACROSS CNY...AND KEEPING THESE AREAS DRY UNTIL CLOSER TO DAYBREAK IF NOT MID FRIDAY MORNING. THE NEW QPF GUIDANCE IS IN FROM HPC AND AGREES WITH MORE EMPHASIS FARTHER SOUTH AND EAST...AND DELAYED TIMING FARTHER NORTH AND WEST. THE PREVIOUS AFD IS BELOW... 3 PM UPDATE... WEAK LOW PRESSURE IN OHIO WILL TRACK ENE INTO SE NY FRI AFTN. AHEAD OF THIS SFC LOW IS A 40 KT LOW LEVEL JET FEEDING MOISTURE INTO THE LIFT AHEAD OF IT. THIS WILL INCREASE AS IT NEARS THE COAST AND TAPS THE ATLANTIC. PWATS RISE TO AROUND 1.5 INCHES. SFC PRESSURE WILL ALSO DECREASE SLOWLY AS IT APPROACHES. LIFT WILL ALSO INCREASE AS THE NORTHERN STREAM MOVES SOUTH PUTTING THE AREA IN THE RIGHT REAR WHILE THE SOUTHERN STREAM MOVES IN FOR THE FRONT LEFT QUAD. MOST OF THE RAIN WILL BE AHEAD OF THE SFC LOW STARTING IN NE PA THIS EVENING THEN INTO THE REST OF THE AREA LATE TONIGHT. THE RAIN WILL TAPER OFF FROM SW TO NE FRIDAY AFTERNOON. RAINFALL AMOUNTS WILL RANGE FROM A THIRD OF AN INCH IN THE CENTRAL SOUTHERN TIER AND FINGER LAKES OF NY TO JUST OVER AN INCH IN NE PA AND THE CATSKILLS. SOME LOCATIONS COULD APPROACH TWO INCHES DUE TO UPSLOPE FLOW. THIS AMOUNT OF RAIN WILL NOT CAUSE ANY FLASH FLOODING. RIVERS WILL RISE SOME BUT REMAIN WELL BELOW BANK FULL. FOR TEMPERATURES WENT ON THE WARM SIDE TONIGHT WITH CLOUDS COMING IN ATTM. FRIDAY GUIDANCE SIMILAR AND WENT CLOSE. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... 3 PM UPDATE... AFTER A QUIET MAINLY DRY PERIOD FRIDAY NIGHT TO SATURDAY NIGHT SHOWERS WILL RETURN STARTING SUNDAY. FRIDAY NIGHT PARTIAL CLEARING WITH WEAK HIGH PRESSURE. THE SFC LOW WILL CONTINUE EAST TO THE GULF OF MAINE. THE CWA WILL BE WAITING FOR THE NEXT SYSTEM WITH A DEEP UPPER LEVEL TROF DROPPING SE INTO NY. MODELS SLOWER WITH THIS FEATURE SO SATURDAY IS LOOKING BETTER. TEMPERATURES NEAR NORMAL BUT MOSTLY CLOUDY STILL. SOME LOW LEVEL MOISTURE OFF OF THE LAKES WILL BRING SOME CUMULUS. 850MB TEMPS FALL BACK TO PLUS 3C. MODELS DIFFER ON THE TIMING OF THE UPPER LEVEL TROF. MOST OF THE DIFFERENCE IS IN THE EXIT DURING THE EARLY PART OF THE LONG TERM. MOST MODELS HAVE THE LOW OVER NY AND PA LATE SUNDAY. THE COLD AIR ALOFT COMBINED WITH EARLY DAY SUNSHINE AND HEATING WILL MEAN SHOWERS WILL INCREASE IN COVERAGE AND INTENSITY. HIGH TEMPS NEAR NORMAL MIDDAY BEFORE FALLING IN THE SHOWERS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 320 AM UPDATE... DRY PERIOD EXPECTED EARLY NEXT WEEK FOLLOWING DEPARTURE OF THIS WEEKEND/S UPPER LOW. SOME QUESTIONS STILL REMAIN WITH RESPECT TO POSSIBLE COLD FRONT WHICH IS ADVERTISED BY THE GFS TO PASS WED AFTERNOON EVENING. THIS SOLUTION HAS VERY LITTLE SUPPORT FROM THE 00Z ECMWF WHICH TAKES A SFC LOW UP THE MID-ATLANTIC COAST DURING THIS TIME FRAME. THE ECMWF HAS BEEN ADVERTISING THIS IN RECENT RUNS AND BASED ON THIS...HAVE ELECTED TO INCREASE POPS BOTH TUE AND TUE NGT. FOLLOWING THIS SYSTEM/S DEPARTURE...DRIER WX LOOKS TO PREVAIL THROUGH THE DURATION OF THE EXTENDED PERIOD WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPS. PREVIOUS LONG TERM DISCUSSION... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... LATEST RADAR TRENDS SHOWING MAIN RAIN SHIELD PUSHING THROUGH THE TWIN TIERS AND REMAINDER OF NE PA THIS HR. SO FAR CONDITIONS HAVE LARGELY REMAINED VFR...HOWEVER EXPECT CATEGORICAL DETERIORATION WITHIN THE NEXT FEW HRS FOR ALL SITES EXCEPT SYR AND RME WHERE RAIN SHIELD SHOULD REMAIN SOUTH. FOR NOW EXPECT IFR CONDITIONS ARE BGM AFTER 08Z...WITH ELM/ITH/AVP LARGELY EXPECTED TO REMAIN MVFR. CLOUDS WILL BE SLOW TO GO WITH MVFR CONDITIONS EXPECTED THROUGH EARLY TO MID AFTERNOON. BEYOND THIS...DRIER AIR WILL MOVE INTO THE REGION WHICH SHOULD RESULT IN GRADUAL IMPROVEMENT TOWARDS 00Z. LIGHT EASTERLY WINDS EARLY ON WILL GRADUALLY SHIFT TOWARDS THE NORTHWEST (5-10 KTS) BY AFTERNOON AS LOW EXITS TO THE EAST. OUTLOOK... SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...TAC NEAR TERM...HEDEN/PVN SHORT TERM...TAC LONG TERM...CMG/RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
151 AM EDT FRI SEP 28 2012 .SYNOPSIS... CONDITIONS WILL DETERIORATE QUICKLY TONIGHT, AS LOW PRESSURE TRACKS TOWARDS OUR AREA FROM OHIO. RAIN WILL MOSTLY FALL LATE TONIGHT AND FRIDAY MORNING BEFORE ENDING FRIDAY AFTERNOON. SATURDAY, WEAK HIGH PRESSURE WILL BRING MAINLY DRY WEATHER. UNSETTLED CONDITIONS WILL RETURN SUNDAY INTO MONDAY AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE NORTHEAST UNITED STATES. && .NEAR TERM /THROUGH TODAY/... 12 AM UPDATE.. QUICK UPDATE TO RMV POPS ACRS THE FAR NORTH FOR TONIGHT. RADAR POPUP SKEW-T ACRS THE NRN ZONES INDICATE DRY LAYER FM SFC-H7. 00Z RAOBS INDICATE SAT/D AIRMASS TO THE SOUTH AND DRY AIR TO THE NORTH. THIS APPEARS TO SUPPORT BUFKIT SNDGS AND 00Z NAM GUIDANCE INDICATES A SLOW SATURATION OF ATMOS AFT 12Z ACRS THE NORTH...THUS HV TRIMMED POPS BACK THRU 12Z. PREVIOUS AFD BELOW. 9 PM UPDATE... RAIN NOW MOVING INTO NEPA. FROM RADAR RETURNS BIGGEST IMPACT WILL REMAIN HERE FOR THE NEXT FEW HOURS...WITH VERY LIGHT SHOWERS JUST GETTING INTO THE SOUTHERN TIER OF NY...WITH DRY WEATHER NORTH OF HERE. 7 PM UPDATE... AN AREA OF LIGHT RAIN ACROSS CENTRAL PA CONTINUES TO SLOWLY LIFT NORTHEAST BUT IS HAVING SOME TROUBLE AT THE MOMENT AS HIGH PRESSURE OVER QUEBEC IS SLOW TO LOSE ITS GRIP ON OUR AREA. THIS IS MOST EVIDENT WITH A QUICK GLANCE AT SURFACE DEW POINTS...SHOWING LOW TO MID 40S ACROSS CNY...BUT CREEPING INTO THE MID 50S DOWN IN NEPA. AS OUR ATMOSPHERE CONTINUES TO MOISTEN UP AND WE BEGIN TO SEE A MID DECK AROUND 5KFT DEVELOP...SHOWERS ARE LIKELY IN NEPA BETWEEN 02Z AND 04Z...OR JUST A TAD SLOWER THAN THE PREVIOUS FORECAST. THE 18Z NAM...ALONG WITH THE HIGHER RESOLUTION MODELS OF THE ARW/NMM AND HRRR CONTINUE TO SUGGEST THAT IT WILL BE HARD FOR PRECIP TO MAKE IT MUCH FARTHER NORTH THAN THE NY/PA LINE THROUGH 06Z. IN FACT...THE BIGGEST ADJUSTMENT WITH THIS PACKAGE WAS DELAYING THE RAIN MUCH LONGER ACROSS CNY...AND KEEPING THESE AREAS DRY UNTIL CLOSER TO DAYBREAK IF NOT MID FRIDAY MORNING. THE NEW QPF GUIDANCE IS IN FROM HPC AND AGREES WITH MORE EMPHASIS FARTHER SOUTH AND EAST...AND DELAYED TIMING FARTHER NORTH AND WEST. THE PREVIOUS AFD IS BELOW... 3 PM UPDATE... WEAK LOW PRESSURE IN OHIO WILL TRACK ENE INTO SE NY FRI AFTN. AHEAD OF THIS SFC LOW IS A 40 KT LOW LEVEL JET FEEDING MOISTURE INTO THE LIFT AHEAD OF IT. THIS WILL INCREASE AS IT NEARS THE COAST AND TAPS THE ATLANTIC. PWATS RISE TO AROUND 1.5 INCHES. SFC PRESSURE WILL ALSO DECREASE SLOWLY AS IT APPROACHES. LIFT WILL ALSO INCREASE AS THE NORTHERN STREAM MOVES SOUTH PUTTING THE AREA IN THE RIGHT REAR WHILE THE SOUTHERN STREAM MOVES IN FOR THE FRONT LEFT QUAD. MOST OF THE RAIN WILL BE AHEAD OF THE SFC LOW STARTING IN NE PA THIS EVENING THEN INTO THE REST OF THE AREA LATE TONIGHT. THE RAIN WILL TAPER OFF FROM SW TO NE FRIDAY AFTERNOON. RAINFALL AMOUNTS WILL RANGE FROM A THIRD OF AN INCH IN THE CENTRAL SOUTHERN TIER AND FINGER LAKES OF NY TO JUST OVER AN INCH IN NE PA AND THE CATSKILLS. SOME LOCATIONS COULD APPROACH TWO INCHES DUE TO UPSLOPE FLOW. THIS AMOUNT OF RAIN WILL NOT CAUSE ANY FLASH FLOODING. RIVERS WILL RISE SOME BUT REMAIN WELL BELOW BANK FULL. FOR TEMPERATURES WENT ON THE WARM SIDE TONIGHT WITH CLOUDS COMING IN ATTM. FRIDAY GUIDANCE SIMILAR AND WENT CLOSE. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... 3 PM UPDATE... AFTER A QUIET MAINLY DRY PERIOD FRIDAY NIGHT TO SATURDAY NIGHT SHOWERS WILL RETURN STARTING SUNDAY. FRIDAY NIGHT PARTIAL CLEARING WITH WEAK HIGH PRESSURE. THE SFC LOW WILL CONTINUE EAST TO THE GULF OF MAINE. THE CWA WILL BE WAITING FOR THE NEXT SYSTEM WITH A DEEP UPPER LEVEL TROF DROPPING SE INTO NY. MODELS SLOWER WITH THIS FEATURE SO SATURDAY IS LOOKING BETTER. TEMPERATURES NEAR NORMAL BUT MOSTLY CLOUDY STILL. SOME LOW LEVEL MOISTURE OFF OF THE LAKES WILL BRING SOME CUMULUS. 850MB TEMPS FALL BACK TO PLUS 3C. MODELS DIFFER ON THE TIMING OF THE UPPER LEVEL TROF. MOST OF THE DIFFERENCE IS IN THE EXIT DURING THE EARLY PART OF THE LONG TERM. MOST MODELS HAVE THE LOW OVER NY AND PA LATE SUNDAY. THE COLD AIR ALOFT COMBINED WITH EARLY DAY SUNSHINE AND HEATING WILL MEAN SHOWERS WILL INCREASE IN COVERAGE AND INTENSITY. HIGH TEMPS NEAR NORMAL MIDDAY BEFORE FALLING IN THE SHOWERS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... LATEST RADAR TRENDS SHOWING MAIN RAIN SHIELD PUSHING THROUGH THE TWIN TIERS AND REMAINDER OF NE PA THIS HR. SO FAR CONDITIONS HAVE LARGELY REMAINED VFR...HOWEVER EXPECT CATEGORICAL DETERIORATION WITHIN THE NEXT FEW HRS FOR ALL SITES EXCEPT SYR AND RME WHERE RAIN SHIELD SHOULD REMAIN SOUTH. FOR NOW EXPECT IFR CONDITIONS ARE BGM AFTER 08Z...WITH ELM/ITH/AVP LARGELY EXPECTED TO REMAIN MVFR. CLOUDS WILL BE SLOW TO GO WITH MVFR CONDITIONS EXPECTED THROUGH EARLY TO MID AFTERNOON. BEYOND THIS...DRIER AIR WILL MOVE INTO THE REGION WHICH SHOULD RESULT IN GRADUAL IMPROVEMENT TOWARDS 00Z. LIGHT EASTERLY WINDS EARLY ON WILL GRADUALLY SHIFT TOWARDS THE NORTHWEST (5-10 KTS) BY AFTERNOON AS LOW EXITS TO THE EAST. OUTLOOK... SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...TAC NEAR TERM...HEDEN/PVN SHORT TERM...TAC LONG TERM...RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1227 AM EDT FRI SEP 28 2012 .SYNOPSIS... CONDITIONS WILL DETERIORATE QUICKLY TONIGHT, AS LOW PRESSURE TRACKS TOWARDS OUR AREA FROM OHIO. RAIN WILL MOSTLY FALL LATE TONIGHT AND FRIDAY MORNING BEFORE ENDING FRIDAY AFTERNOON. SATURDAY, WEAK HIGH PRESSURE WILL BRING MAINLY DRY WEATHER. UNSETTLED CONDITIONS WILL RETURN SUNDAY INTO MONDAY AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH THE NORTHEAST UNITED STATES. && .NEAR TERM /THROUGH TODAY/... 12 AM UPDATE.. QUICK UPDATE TO RMV POPS ACRS THE FAR NORTH FOR TONIGHT. RADAR POPUP SKEW-T ACRS THE NRN ZONES INDICATE DRY LAYER FM SFC-H7. 00Z RAOBS INDICATE SAT/D AIRMASS TO THE SOUTH AND DRY AIR TO THE NORTH. THIS APPEARS TO SUPPORT BUFKIT SNDGS AND 00Z NAM GUIDANCE INDICATES A SLOW SATURATION OF ATMOS AFT 12Z ACRS THE NORTH...THUS HV TRIMMED POPS BACK THRU 12Z. PREVIOUS AFD BELOW. 9 PM UPDATE... RAIN NOW MOVING INTO NEPA. FROM RADAR RETURNS BIGGEST IMPACT WILL REMAIN HERE FOR THE NEXT FEW HOURS...WITH VERY LIGHT SHOWERS JUST GETTING INTO THE SOUTHERN TIER OF NY...WITH DRY WEATHER NORTH OF HERE. 7 PM UPDATE... AN AREA OF LIGHT RAIN ACROSS CENTRAL PA CONTINUES TO SLOWLY LIFT NORTHEAST BUT IS HAVING SOME TROUBLE AT THE MOMENT AS HIGH PRESSURE OVER QUEBEC IS SLOW TO LOSE ITS GRIP ON OUR AREA. THIS IS MOST EVIDENT WITH A QUICK GLANCE AT SURFACE DEW POINTS...SHOWING LOW TO MID 40S ACROSS CNY...BUT CREEPING INTO THE MID 50S DOWN IN NEPA. AS OUR ATMOSPHERE CONTINUES TO MOISTEN UP AND WE BEGIN TO SEE A MID DECK AROUND 5KFT DEVELOP...SHOWERS ARE LIKELY IN NEPA BETWEEN 02Z AND 04Z...OR JUST A TAD SLOWER THAN THE PREVIOUS FORECAST. THE 18Z NAM...ALONG WITH THE HIGHER RESOLUTION MODELS OF THE ARW/NMM AND HRRR CONTINUE TO SUGGEST THAT IT WILL BE HARD FOR PRECIP TO MAKE IT MUCH FARTHER NORTH THAN THE NY/PA LINE THROUGH 06Z. IN FACT...THE BIGGEST ADJUSTMENT WITH THIS PACKAGE WAS DELAYING THE RAIN MUCH LONGER ACROSS CNY...AND KEEPING THESE AREAS DRY UNTIL CLOSER TO DAYBREAK IF NOT MID FRIDAY MORNING. THE NEW QPF GUIDANCE IS IN FROM HPC AND AGREES WITH MORE EMPHASIS FARTHER SOUTH AND EAST...AND DELAYED TIMING FARTHER NORTH AND WEST. THE PREVIOUS AFD IS BELOW... 3 PM UPDATE... WEAK LOW PRESSURE IN OHIO WILL TRACK ENE INTO SE NY FRI AFTN. AHEAD OF THIS SFC LOW IS A 40 KT LOW LEVEL JET FEEDING MOISTURE INTO THE LIFT AHEAD OF IT. THIS WILL INCREASE AS IT NEARS THE COAST AND TAPS THE ATLANTIC. PWATS RISE TO AROUND 1.5 INCHES. SFC PRESSURE WILL ALSO DECREASE SLOWLY AS IT APPROACHES. LIFT WILL ALSO INCREASE AS THE NORTHERN STREAM MOVES SOUTH PUTTING THE AREA IN THE RIGHT REAR WHILE THE SOUTHERN STREAM MOVES IN FOR THE FRONT LEFT QUAD. MOST OF THE RAIN WILL BE AHEAD OF THE SFC LOW STARTING IN NE PA THIS EVENING THEN INTO THE REST OF THE AREA LATE TONIGHT. THE RAIN WILL TAPER OFF FROM SW TO NE FRIDAY AFTERNOON. RAINFALL AMOUNTS WILL RANGE FROM A THIRD OF AN INCH IN THE CENTRAL SOUTHERN TIER AND FINGER LAKES OF NY TO JUST OVER AN INCH IN NE PA AND THE CATSKILLS. SOME LOCATIONS COULD APPROACH TWO INCHES DUE TO UPSLOPE FLOW. THIS AMOUNT OF RAIN WILL NOT CAUSE ANY FLASH FLOODING. RIVERS WILL RISE SOME BUT REMAIN WELL BELOW BANK FULL. FOR TEMPERATURES WENT ON THE WARM SIDE TONIGHT WITH CLOUDS COMING IN ATTM. FRIDAY GUIDANCE SIMILAR AND WENT CLOSE. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... 3 PM UPDATE... AFTER A QUIET MAINLY DRY PERIOD FRIDAY NIGHT TO SATURDAY NIGHT SHOWERS WILL RETURN STARTING SUNDAY. FRIDAY NIGHT PARTIAL CLEARING WITH WEAK HIGH PRESSURE. THE SFC LOW WILL CONTINUE EAST TO THE GULF OF MAINE. THE CWA WILL BE WAITING FOR THE NEXT SYSTEM WITH A DEEP UPPER LEVEL TROF DROPPING SE INTO NY. MODELS SLOWER WITH THIS FEATURE SO SATURDAY IS LOOKING BETTER. TEMPERATURES NEAR NORMAL BUT MOSTLY CLOUDY STILL. SOME LOW LEVEL MOISTURE OFF OF THE LAKES WILL BRING SOME CUMULUS. 850MB TEMPS FALL BACK TO PLUS 3C. MODELS DIFFER ON THE TIMING OF THE UPPER LEVEL TROF. MOST OF THE DIFFERENCE IS IN THE EXIT DURING THE EARLY PART OF THE LONG TERM. MOST MODELS HAVE THE LOW OVER NY AND PA LATE SUNDAY. THE COLD AIR ALOFT COMBINED WITH EARLY DAY SUNSHINE AND HEATING WILL MEAN SHOWERS WILL INCREASE IN COVERAGE AND INTENSITY. HIGH TEMPS NEAR NORMAL MIDDAY BEFORE FALLING IN THE SHOWERS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL LOW OVER NEW YORK STATE WHICH LIFTS INTO EASTERN CANADA ON MONDAY. THIS FEATURE WILL PROVIDE A CONTINUATION OF SHOWERY WEATHER THROUGH SUNDAY NIGHT WITH GRADUAL IMPROVEMENT ON MONDAY. MONDAY NIGHT THROUGH WEDNESDAY, UPPER LEVEL FLOW BECOMES MORE ZONAL WITH AREA BETWEEN TWO SYSTEMS, A WEAK TROF IN EASTERN CANADA AND SFC LOW IN THE MID ATLANTIC. REGION MAY REMAIN DRY THROUGH THIS PERIOD BUT DUE TO LACK OF MODEL RUN TO RUN CONTINUITY CONFIDENCE NOT VERY HIGH. ON THURSDAY, RETURN FLOW ON BACK SIDE OF SFC HIGH PRES OFF THE MID ATLANTIC COAST MAY BRING THE THREAT FOR SHOWERS ESPECIALLY IN THE SOUTHERN FORECAST AREA. TEMPS THROUGH PERIOD WILL RUN 5 TO 10 DEGREES ABOVE NORMAL. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... 00Z FRI UPDATE... VFR WILL CONTINUE THIS EVE...BEFORE CONDS DETERIORATE LATER TNT INTO FRI...AS LWR CIGS AND RAIN MOVE IN FOR KAVP...KELM...KBGM...AND KITH. THE MOST PERSISTENT RAIN SHOULD OCCUR AT KAVP (MORE INTERMITTENT AT KELM...KBGM...AND KITH)...BUT MVFR CONDS SHOULD PREVAIL AT EACH SITE. IN GENERAL...STEADIER RAIN SHOULD TAPER OFF BY MIDDAY FRI...BUT MVFR CIGS ARE LIKELY TO LAST LONGER. FOR KSYR AND KRME...VFR IS EXPECTED TO REMAIN PREVALENT...AS THE RAIN SHIELD LARGELY BYPASSES THESE SITES TO THE S. LGT SFC WINDS OVERNIGHT (AOB 5 KT)...WILL BECOME N TO NW AND INCREASE TO ARND 10 KT FRI. OUTLOOK... FRI NGT...IMPROVING TO VFR. SAT...GENERALLY VFR. SUNDAY THROUGH MONDAY...MVFR SHOWERS POSSIBLE. TUESDAY...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...TAC NEAR TERM...HEDEN/PVN SHORT TERM...TAC LONG TERM...RRM AVIATION...MLJ/RRM
AREA FORECAST DISCUSSION
NWS NORMAN OK
1034 AM CDT FRI SEP 28 2012 .DISCUSSION... THE AREA OF RAIN OVER TEXAS...JUST SOUTH AND SOUTHWEST OF OUR TEXAS COUNTIES...SEEMS TO BE STRUGGLING TO EXPAND INTO OUR COUNTIES. NEVERTHELESS...SHORT-RANGE MODELS CONTINUE TO BRING THE RAIN INTO WESTERN NORTH TEXAS DURING THE DAY TODAY. SO...WILL RETAIN THE HIGH POPS IN THAT AREA. SIMILARLY...MODELS SUPPORT THE LOWER POPS ELSEWHERE. GIVEN THE VERY MOIST ATMOSPHERE...IT IS HARD TO RULE OUT THE CHANCE OF RAIN ANYWHERE IN OUR FORECAST AREA TODAY. ALL THE OTHER FORECAST ELEMENTS ALSO APPEAR TO BE WELL- HANDLED...SO NO CHANGES ARE PLANNED FOR THIS MORNING. && .PREV DISCUSSION... /ISSUED 654 AM CDT FRI SEP 28 2012/ DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. AVIATION... GENERALLY HAVE VERY LOW CONFIDENCE AT ALL SITES THROUGH 18Z...THEN MODERATE CONFIDENCE 18-03Z...THEN LOW CONFIDENCE AFTER 03Z. VLIFR CONDITIONS AND FG WILL OCCUR NEAR KOKC...KPNC... KCSM...AND KHBR THROUGH AT LEAST 14Z...AND MAY LINGER AS LONG AS 17Z. MVFR CONDITIONS ARE EXPECTED NEAR KSPS...KOUN...AND KLAW THROUGH AT LEAST 14Z. BY 18Z...WENT OPTIMISTIC WITH VFR CONDITIONS EVERYWHERE. MVFR OR LOWER CONDITIONS MAY RETURN TO ANY SITE AFTER 03Z...ESPECIALLY OVER NORTHERN OKLAHOMA WHERE BR/FG MAY REDEVELOP AND WITH -RA/BR OVER SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. WENT MVFR CONDITIONS WITH -RA/BR AT KSPS AFTER 06Z WHERE CONFIDENCE IS SLIGHTLY HIGHER. MBS PREV DISCUSSION... /ISSUED 431 AM CDT FRI SEP 28 2012/ DISCUSSION... FOG THIS MORNING AND RAIN CHANCES THROUGH SUNDAY NIGHT ARE THE MAIN CONCERNS. THROUGH 11 AM CDT THIS MORNING...AREAS OF FOG WILL REDUCE VISIBILITIES BELOW 1 MILE IN SOME LOCATIONS. DO NOT PLAN ON ISSUING A DENSE FOG ADVISORY AS VISIBILITIES SHOULD REMAIN MAINLY ABOVE 1/4 MILE AND AS VARIOUS CLOUD LAYERS SHOULD PREVENT WIDESPREAD DENSE FOG DEVELOPMENT. AS FOR RAIN CHANCES TODAY...LOWERED THEM EAST OF A PONCA CITY TO WICHITA FALLS LINE...INCLUDING OKLAHOMA CITY DUE TO THE LACK OF LIFT. BASED ON LATEST RADAR AND HRRR RUNS... CURRENT SHOWERS OVER FAR NORTHWEST OKLAHOMA WILL LIKELY DISSIPATE BY 11 AM CDT AS THE LOW LEVEL JET WEAKENS AND A MID LEVEL DISTURBANCE OVER THE CENTRAL PLAINS PULLS NORTHEAST OF THE AREA. INCREASING RAIN CHANCES WILL ARRIVE THIS AFTERNOON OVER WESTERN NORTH TEXAS AND FAR SOUTHWESTERN OKLAHOMA AHEAD OF AN EJECTING MID LEVEL DISTURBANCE NEAR THE GULF OF CALIFORNIA. CANNOT RULE OUT ISOLATED NEW DEVELOPMENT NEARLY ANYWHERE TODAY AS THE AIR IS VERY MOIST...BUT THIS SEEMS UNLIKELY...ESPECIALLY AS ABUNDANT CLOUD COVER WILL MAKE REACHING CONVECTIVE TEMPERATURES IN THE 81 TO 86 DEGREE RANGE DIFFICULT. THERE IS A LOW CHANCE FOR LOCALLY HEAVY RAINFALL WITH ANY SHOWER OR STORM TODAY WITH PRECIPITABLE WATER VALUES ABOUT 150 PERCENT OF NORMAL AND SLOW STORM MOVEMENT. HOWEVER...LACK OF SIGNIFICANT INSTABILITY AND FAIRLY WEAK SHEAR WILL KEEP ANY HEAVY RAINFALL LOCALIZED. SEVERE STORMS ARE UNLIKELY AS WELL. WENT NEAR OR SLIGHTLY BELOW 00Z MOS GUIDANCE TEMPERATURES FOR HIGHS TODAY DUE TO ABUNDANT CLOUD COVER COVER. TONIGHT INTO SATURDAY...RAIN CHANCES MAY INCREASE...ESPECIALLY OVER WESTERN NORTH TEXAS AND SOUTHERN OKLAHOMA AS THE POORLY SAMPLED LOW PRESSURE DISTURBANCE MENTIONED ABOVE APPROACHES. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE DUE TO HIGH PRECIPITABLE WATER VALUES...THOUGH CONFIDENCE REMAINS LOW. NO SEVERE STORMS ARE EXPECTED. WENT TOWARDS THE COOLER 00Z GUIDANCE HIGHS ON SATURDAY DUE TO ABUNDANT CLOUD COVER. THERE IS AN OUTSIDE SHOT FOG MAY DEVELOP OVER NORTHERN OKLAHOMA IF SKIES CAN CLEAR. SATURDAY NIGHT INTO SUNDAY NIGHT...FOG DEVELOPMENT MAY BE CONCERN...ESPECIALLY SUNDAY MORNING ACROSS THE AREA. WAS NOT CONFIDENT TO MENTION. KEPT LOW RAIN CHANCES OVER SOUTHEAST OKLAHOMA AS WELL AS FAR WESTERN OKLAHOMA AND NORTH TEXAS DURING THIS TIME FRAME. MONDAY THROUGH THURSDAY...DRY AND WARMER WEATHER CAN BE EXPECTED. ABOVE AVERAGE TEMPERATURES ARE FORECAST...THOUGH CONFIDENCE IS NOT THE GREATEST...ESPECIALLY WEDNESDAY AND BEYOND AS ANOTHER COLD FRONT MAY MOVE THROUGH THE AREA. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 79 64 77 60 / 20 30 30 10 HOBART OK 74 64 79 59 / 50 50 30 10 WICHITA FALLS TX 79 66 77 62 / 50 50 50 20 GAGE OK 77 58 77 55 / 50 30 20 10 PONCA CITY OK 79 58 79 53 / 30 20 10 10 DURANT OK 85 66 75 63 / 30 60 60 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 23/04
AREA FORECAST DISCUSSION
NWS NORMAN OK
654 AM CDT FRI SEP 28 2012 .DISCUSSION... AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW. && .AVIATION... GENERALLY HAVE VERY LOW CONFIDENCE AT ALL SITES THROUGH 18Z...THEN MODERATE CONFIDENCE 18-03Z...THEN LOW CONFIDENCE AFTER 03Z. VLIFR CONDITIONS AND FG WILL OCCUR NEAR KOKC...KPNC... KCSM...AND KHBR THROUGH AT LEAST 14Z...AND MAY LINGER AS LONG AS 17Z. MVFR CONDITIONS ARE EXPECTED NEAR KSPS...KOUN...AND KLAW THROUGH AT LEAST 14Z. BY 18Z...WENT OPTIMISTIC WITH VFR CONDITIONS EVERYWHERE. MVFR OR LOWER CONDITIONS MAY RETURN TO ANY SITE AFTER 03Z...ESPECIALLY OVER NORTHERN OKLAHOMA WHERE BR/FG MAY REDEVELOP AND WITH -RA/BR OVER SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS. WENT MVFR CONDITIONS WITH -RA/BR AT KSPS AFTER 06Z WHERE CONFIDENCE IS SLIGHTLY HIGHER. MBS && .PREV DISCUSSION... /ISSUED 431 AM CDT FRI SEP 28 2012/ DISCUSSION... FOG THIS MORNING AND RAIN CHANCES THROUGH SUNDAY NIGHT ARE THE MAIN CONCERNS. THROUGH 11 AM CDT THIS MORNING...AREAS OF FOG WILL REDUCE VISIBILITIES BELOW 1 MILE IN SOME LOCATIONS. DO NOT PLAN ON ISSUING A DENSE FOG ADVISORY AS VISIBILITIES SHOULD REMAIN MAINLY ABOVE 1/4 MILE AND AS VARIOUS CLOUD LAYERS SHOULD PREVENT WIDESPREAD DENSE FOG DEVELOPMENT. AS FOR RAIN CHANCES TODAY...LOWERED THEM EAST OF A PONCA CITY TO WICHITA FALLS LINE...INCLUDING OKLAHOMA CITY DUE TO THE LACK OF LIFT. BASED ON LATEST RADAR AND HRRR RUNS... CURRENT SHOWERS OVER FAR NORTHWEST OKLAHOMA WILL LIKELY DISSIPATE BY 11 AM CDT AS THE LOW LEVEL JET WEAKENS AND A MID LEVEL DISTURBANCE OVER THE CENTRAL PLAINS PULLS NORTHEAST OF THE AREA. INCREASING RAIN CHANCES WILL ARRIVE THIS AFTERNOON OVER WESTERN NORTH TEXAS AND FAR SOUTHWESTERN OKLAHOMA AHEAD OF AN EJECTING MID LEVEL DISTURBANCE NEAR THE GULF OF CALIFORNIA. CANNOT RULE OUT ISOLATED NEW DEVELOPMENT NEARLY ANYWHERE TODAY AS THE AIR IS VERY MOIST...BUT THIS SEEMS UNLIKELY...ESPECIALLY AS ABUNDANT CLOUD COVER WILL MAKE REACHING CONVECTIVE TEMPERATURES IN THE 81 TO 86 DEGREE RANGE DIFFICULT. THERE IS A LOW CHANCE FOR LOCALLY HEAVY RAINFALL WITH ANY SHOWER OR STORM TODAY WITH PRECIPITABLE WATER VALUES ABOUT 150 PERCENT OF NORMAL AND SLOW STORM MOVEMENT. HOWEVER...LACK OF SIGNIFICANT INSTABILITY AND FAIRLY WEAK SHEAR WILL KEEP ANY HEAVY RAINFALL LOCALIZED. SEVERE STORMS ARE UNLIKELY AS WELL. WENT NEAR OR SLIGHTLY BELOW 00Z MOS GUIDANCE TEMPERATURES FOR HIGHS TODAY DUE TO ABUNDANT CLOUD COVER COVER. TONIGHT INTO SATURDAY...RAIN CHANCES MAY INCREASE...ESPECIALLY OVER WESTERN NORTH TEXAS AND SOUTHERN OKLAHOMA AS THE POORLY SAMPLED LOW PRESSURE DISTURBANCE MENTIONED ABOVE APPROACHES. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE DUE TO HIGH PRECIPITABLE WATER VALUES...THOUGH CONFIDENCE REMAINS LOW. NO SEVERE STORMS ARE EXPECTED. WENT TOWARDS THE COOLER 00Z GUIDANCE HIGHS ON SATURDAY DUE TO ABUNDANT CLOUD COVER. THERE IS AN OUTSIDE SHOT FOG MAY DEVELOP OVER NORTHERN OKLAHOMA IF SKIES CAN CLEAR. SATURDAY NIGHT INTO SUNDAY NIGHT...FOG DEVELOPMENT MAY BE CONCERN...ESPECIALLY SUNDAY MORNING ACROSS THE AREA. WAS NOT CONFIDENT TO MENTION. KEPT LOW RAIN CHANCES OVER SOUTHEAST OKLAHOMA AS WELL AS FAR WESTERN OKLAHOMA AND NORTH TEXAS DURING THIS TIME FRAME. MONDAY THROUGH THURSDAY...DRY AND WARMER WEATHER CAN BE EXPECTED. ABOVE AVERAGE TEMPERATURES ARE FORECAST...THOUGH CONFIDENCE IS NOT THE GREATEST...ESPECIALLY WEDNESDAY AND BEYOND AS ANOTHER COLD FRONT MAY MOVE THROUGH THE AREA. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 79 64 77 60 / 20 30 30 10 HOBART OK 74 64 79 59 / 50 50 30 10 WICHITA FALLS TX 79 66 77 62 / 50 50 50 20 GAGE OK 77 58 77 55 / 50 30 20 10 PONCA CITY OK 79 58 79 53 / 30 20 10 10 DURANT OK 85 66 75 63 / 30 60 60 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17/17
AREA FORECAST DISCUSSION
NWS NORMAN OK
431 AM CDT FRI SEP 28 2012 .DISCUSSION... FOG THIS MORNING AND RAIN CHANCES THROUGH SUNDAY NIGHT ARE THE MAIN CONCERNS. THROUGH 11 AM CDT THIS MORNING...AREAS OF FOG WILL REDUCE VISIBILITIES BELOW 1 MILE IN SOME LOCATIONS. DO NOT PLAN ON ISSUING A DENSE FOG ADVISORY AS VISIBILITIES SHOULD REMAIN MAINLY ABOVE 1/4 MILE AND AS VARIOUS CLOUD LAYERS SHOULD PREVENT WIDESPREAD DENSE FOG DEVELOPMENT. AS FOR RAIN CHANCES TODAY...LOWERED THEM EAST OF A PONCA CITY TO WICHITA FALLS LINE...INCLUDING OKLAHOMA CITY DUE TO THE LACK OF LIFT. BASED ON LATEST RADAR AND HRRR RUNS... CURRENT SHOWERS OVER FAR NORTHWEST OKLAHOMA WILL LIKELY DISSIPATE BY 11 AM CDT AS THE LOW LEVEL JET WEAKENS AND A MID LEVEL DISTURBANCE OVER THE CENTRAL PLAINS PULLS NORTHEAST OF THE AREA. INCREASING RAIN CHANCES WILL ARRIVE THIS AFTERNOON OVER WESTERN NORTH TEXAS AND FAR SOUTHWESTERN OKLAHOMA AHEAD OF AN EJECTING MID LEVEL DISTURBANCE NEAR THE GULF OF CALIFORNIA. CANNOT RULE OUT ISOLATED NEW DEVELOPMENT NEARLY ANYWHERE TODAY AS THE AIR IS VERY MOIST...BUT THIS SEEMS UNLIKELY...ESPECIALLY AS ABUNDANT CLOUD COVER WILL MAKE REACHING CONVECTIVE TEMPERATURES IN THE 81 TO 86 DEGREE RANGE DIFFICULT. THERE IS A LOW CHANCE FOR LOCALLY HEAVY RAINFALL WITH ANY SHOWER OR STORM TODAY WITH PRECIPITABLE WATER VALUES ABOUT 150 PERCENT OF NORMAL AND SLOW STORM MOVEMENT. HOWEVER...LACK OF SIGNIFICANT INSTABILITY AND FAIRLY WEAK SHEAR WILL KEEP ANY HEAVY RAINFALL LOCALIZED. SEVERE STORMS ARE UNLIKELY AS WELL. WENT NEAR OR SLIGHTLY BELOW 00Z MOS GUIDANCE TEMPERATURES FOR HIGHS TODAY DUE TO ABUNDANT CLOUD COVER COVER. TONIGHT INTO SATURDAY...RAIN CHANCES MAY INCREASE...ESPECIALLY OVER WESTERN NORTH TEXAS AND SOUTHERN OKLAHOMA AS THE POORLY SAMPLED LOW PRESSURE DISTURBANCE MENTIONED ABOVE APPROACHES. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE DUE TO HIGH PRECIPITABLE WATER VALUES...THOUGH CONFIDENCE REMAINS LOW. NO SEVERE STORMS ARE EXPECTED. WENT TOWARDS THE COOLER 00Z GUIDANCE HIGHS ON SATURDAY DUE TO ABUNDANT CLOUD COVER. THERE IS AN OUTSIDE SHOT FOG MAY DEVELOP OVER NORTHERN OKLAHOMA IF SKIES CAN CLEAR. SATURDAY NIGHT INTO SUNDAY NIGHT...FOG DEVELOPMENT MAY BE CONCERN...ESPECIALLY SUNDAY MORNING ACROSS THE AREA. WAS NOT CONFIDENT TO MENTION. KEPT LOW RAIN CHANCES OVER SOUTHEAST OKLAHOMA AS WELL AS FAR WESTERN OKLAHOMA AND NORTH TEXAS DURING THIS TIME FRAME. MONDAY THROUGH THURSDAY...DRY AND WARMER WEATHER CAN BE EXPECTED. ABOVE AVERAGE TEMPERATURES ARE FORECAST...THOUGH CONFIDENCE IS NOT THE GREATEST...ESPECIALLY WEDNESDAY AND BEYOND AS ANOTHER COLD FRONT MAY MOVE THROUGH THE AREA. MBS && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 79 64 77 60 / 20 30 30 10 HOBART OK 74 64 79 59 / 50 50 30 10 WICHITA FALLS TX 79 66 77 62 / 50 50 50 20 GAGE OK 77 58 77 55 / 50 30 20 10 PONCA CITY OK 79 58 79 53 / 30 20 10 10 DURANT OK 85 66 75 63 / 30 60 60 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/17
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
748 AM EDT FRI SEP 28 2012 .SYNOPSIS... A STRONG DISTURBANCE ALOFT WILL MOVE EAST OF THE REGION TODAY. DRIER AIR WILL MOVE INTO THE REGION LATER TODAY AND SATURDAY...BEFORE A DEVELOPING UPPER LOW BRINGS MORE UNSETTLED WEATHER LATER IN THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4AM UPDATE... SHORTWAVE TROF AXIS IS MOVING INTO EASTERN PA AT THIS HOUR...WITH THE STEADIEST RAINS NOW MOVING THRU NERN PA. THE TRAILING SHOWERS EXTEND BACK TO THE LOWER SUSQ VALLEY WHERE ACTIVITY WILL WIND DOWN IN THE HOURS NEAR AND JUST AFTER SUNRISE. HRRR TIMING HAS THE LAST OF THE RAINS MOVING OUT OF THE FCST AREA AROUND 14Z. IT WILL BE A MOSTLY CLOUDY DAY WITH BRIGHTENING SKIES FOR THE AFTERNOON. STILL CANNOT RULE OUT A STRAY SHOWER AFTER MID DAY...BUT CHANCES ARE LOW AND FOR NOW I WILL NOT MENTION RAIN. HIGHS TODAY WILL RANGE FROM THE LOW/MID 60S OVER THE FAR NW TO MID 70S OVER THE SE. FOR THE TIME OF YEAR THAT WILL BE A LITTLE COOLER THAN NORMAL NW TO A LITTLE WARMER THAN NORMAL OVER THE SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... EXPECT CLEARING SKIES TONIGHT AS SFC HIGH PRESSURE RIDGES IN FROM THE OHIO VALLEY. IF CLEARING OCCURS EARLY ENOUGH...FOG COULD BECOME AN ISSUE. LOWS WILL BOTTOM OUT VERY NEAR CLIMO NORMS...40S NORTH TO 50S SOUTH. LOW LEVEL COLD ADVECTION AND MOISTURE WILL COMBINE FOR THE DEVELOPMENT OF STRATOCU ON SATURDAY. HAVE PUT A VERY SMALL CHANCE OF RAIN OVER NRN AREAS...WITH LITTLE MORE THAN A FEW SPRINKLES ELSEWHERE. HIGHS IN THE 60S WILL BE A BIT BELOW NORMAL FOR A CHANGE. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... INCREASINGLY UNSETTLED CONDITIONS RETURN BY THE END OF THE WEEKEND AS AN UPPER LOW NEAR JAMES BAY DIVES SSW INTO THE GR LAKES BEFORE EJECTING BACK INTO ERN CANADA BY MONDAY. SUNDAY LOOKS LIKE A COOL AND SHOWERY DAY AS THE UPPER TROF/LOW BOTTOM OUT AND BEGIN TO SLIDE INTO THE AREA. AFTER WE DRY OUT FOR A BIT MONDAY...GUIDANCE STARTS TO DIVERGE FOR MIDWEEK. THE ECMWF IS AGGRESSIVE IN DRAGGING GULF MOISTURE NORTHWARD AS IT CARVES OUT A DEEP TROF OVER THE ERN US BY TUESDAY. OPERATIONAL GFS KEEPS THE SRN MOISTURE AND ENERGY MORE SEPARATE...NOT NEARLY AS AGGRESSIVE AS THE ECMWF. THE GEFS LOOKS VERY MUCH LIKE THE GFS ALOFT...BUT SHOWS HIGHER POPS INTO MID WEEK. WITH CONFLICTING GUIDANCE SUCH AS IT IS...I BROUGHT IN A CHANCE OF RAIN TUES INTO WED. ONCE THE EASTERN SYSTEM IS RESOLVED...THE END OF THE WEEK LOOKS DRIER IN ALL THE GUIDANCE. TEMPS SHOULD ACTUALLY BE A BIT ABOVE NORMAL BEFORE HIGH PRESSURE LIKELY BRINGS COOLER AIR FOR NEXT WEEKEND. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... A WEAK AREA OF SURFACE LOW PRESSURE WAS CENTERED NEAR KMDT AT 1130Z...AND WILL COMBINE WITH A POTENT...AND SLOW MOVING UPPER AIR DISTURBANCE TO BRING NUMEROUS SHOWERS /AND LOW FLYING CONDITIONS/ NEAR AND TO THE EAST OF A LINE FROM KIPT TO KSEG THROUGH 16Z. AFTERWARD...AND ELSEWHERE ACROSS THE REGION MAINLY IFR TO LIFR CIGS /AND MVFR TO IFR VSBYS IN AREAS OF DRIZZLE/ WILL PERSIST AT MOST CENTRAL PENN TAF SITES THROUGH THE REST OF THIS MORNING... BEFORE GRADUAL IMPROVING DURING THE AFTERNOON HOURS. VSBYS WILL BECOME MAINLY VFR THIS AFTERNOON /WITH LINGERING AREAS OF MVFR CIGS/ AS THE LOW PRESSURE AREA MOVES OFF TOWARD THE NEW ENGLAND COAST. AREAS OF MVFR CIGS AND VSBYS WILL PERSIST INTO TONIGHT...MAINLY ACROSS THE HIGHER ELEVATION AIRFIELDS OF WESTERN PENN /KJST...NORTH TO KBFD/. OUTLOOK... SAT...MAINLY VFR. MVFR CIGS POSS NW. SUN...VFR/AREAS OF MVFR IN SHOWERS - MAINLY ACROSS THE WESTERN MTNS OF PENN DURING DAY...BECOMING AREA-WIDE SUN NIGHT. MON...MAINLY VFR...WITH MVFR POSS IN THE MORNING. TUE...VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
503 AM EDT FRI SEP 28 2012 .SYNOPSIS... A STRONG DISTURBANCE ALOFT WILL MOVE EAST OF THE REGION TODAY. DRIER AIR WILL MOVE INTO THE REGION LATER TODAY AND SATURDAY...BEFORE A DEVELOPING UPPER LOW BRINGS MORE UNSETTLED WEATHER LATER IN THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4AM UPDATE... SHORTWAVE TROF AXIS IS MOVING INTO EASTERN PA AT THIS HOUR...WITH THE STEADIEST RAINS NOW MOVING THRU NERN PA. THE TRAILING SHOWERS EXTEND BACK TO THE LOWER SUSQ VALLEY WHERE ACTIVITY WILL WIND DOWN IN THE HOURS NEAR AND JUST AFTER SUNRISE. HRRR TIMING HAS THE LAST OF THE RAINS MOVING OUT OF THE FCST AREA AROUND 14Z. IT WILL BE A MOSTLY CLOUDY DAY WITH BRIGHTENING SKIES FOR THE AFTERNOON. STILL CANNOT RULE OUT A STRAY SHOWER AFTER MID DAY...BUT CHANCES ARE LOW AND FOR NOW I WILL NOT MENTION RAIN. HIGHS TODAY WILL RANGE FROM THE LOW/MID 60S OVER THE FAR NW TO MID 70S OVER THE SE. FOR THE TIME OF YEAR THAT WILL BE A LITTLE COOLER THAN NORMAL NW TO A LITTLE WARMER THAN NORMAL OVER THE SE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... EXPECT CLEARING SKIES TONIGHT AS SFC HIGH PRESSURE RIDGES IN FROM THE OHIO VALLEY. IF CLEARING OCCURS EARLY ENOUGH...FOG COULD BECOME AN ISSUE. LOWS WILL BOTTOM OUT VERY NEAR CLIMO NORMS...40S NORTH TO 50S SOUTH. LOW LEVEL COLD ADVECTION AND MOISTURE WILL COMBINE FOR THE DEVELOPMENT OF STRATOCU ON SATURDAY. HAVE PUT A VERY SMALL CHANCE OF RAIN OVER NRN AREAS...WITH LITTLE MORE THAN A FEW SPRINKLES ELSEWHERE. HIGHS IN THE 60S WILL BE A BIT BELOW NORMAL FOR A CHANGE. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... INCREASINGLY UNSETTLED CONDITIONS RETURN BY THE END OF THE WEEKEND AS AN UPPER LOW NEAR JAMES BAY DIVES SSW INTO THE GR LAKES BEFORE EJECTING BACK INTO ERN CANADA BY MONDAY. SUNDAY LOOKS LIKE A COOL AND SHOWERY DAY AS THE UPPER TROF/LOW BOTTOM OUT AND BEGIN TO SLIDE INTO THE AREA. AFTER WE DRY OUT FOR A BIT MONDAY...GUIDANCE STARTS TO DIVERGE FOR MIDWEEK. THE ECMWF IS AGGRESSIVE IN DRAGGING GULF MOISTURE NORTHWARD AS IT CARVES OUT A DEEP TROF OVER THE ERN US BY TUESDAY. OPERATIONAL GFS KEEPS THE SRN MOISTURE AND ENERGY MORE SEPARATE...NOT NEARLY AS AGGRESSIVE AS THE ECMWF. THE GEFS LOOKS VERY MUCH LIKE THE GFS ALOFT...BUT SHOWS HIGHER POPS INTO MID WEEK. WITH CONFLICTING GUIDANCE SUCH AS IT IS...I BROUGHT IN A CHANCE OF RAIN TUES INTO WED. ONCE THE EASTERN SYSTEM IS RESOLVED...THE END OF THE WEEK LOOKS DRIER IN ALL THE GUIDANCE. TEMPS SHOULD ACTUALLY BE A BIT ABOVE NORMAL BEFORE HIGH PRESSURE LIKELY BRINGS COOLER AIR FOR NEXT WEEKEND. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... SLOW MOVING SURFACE LOW PRESSURE CENTERED NEAR KUNV AT 06Z...WILL COMBINE WITH A POTENT UPPER AIR DISTURBANCE TO BRING WIDESPREAD MODERATE TO HEAVY RAIN SHOWERS /AND LOW FLYING CONDITIONS/ NEAR AND TO THE EAST OF A LINE FROM KHGR...TO KMDT...KSEG AND KIPT THROUGH 09Z. AFTERWARD...AND ELSEWHERE ACROSS THE REGION IFR TO LIFR CIGS /AND MVFR TO IFR VSBYS IN AREAS OF LIGHTER SHOWERS AND DRIZZLE/ WILL PERSIST AT MOST CENTRAL PENN TAF SITES THROUGH 14Z BEFORE GRADUAL IMPROVING FOR THE LATE MORNING AND AFTERNOON HOURS. VSBYS WILL BECOME MAINLY VFR THIS FRIDAY AFTERNOON AS THE LOW PRESSURE AREA MOVES OFF TOWARD THE NEW ENGLAND COAST...BUT AREAS OF MVFR VSBYS WILL PERSIST INTO TONIGHT...MAINLY ACROSS THE HIGHER ELEVATION AIRFIELDS OF WESTERN PENN /KJST...NORTH TO KBFD/. OUTLOOK... SAT...MAINLY VFR. MVFR CIGS POSS NW. SUN...VFR/AREAS OF MVFR IN SHOWERS - MAINLY WEST DURING DAY...AREA-WIDE SUN NIGHT. MON...MAINLY VFR...WITH MVFR POSS IN THE MORNING. TUE...VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...LAMBERT/RXR
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AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
126 PM EDT FRI SEP 28 2012 .SYNOPSIS... A COLD FRONT WILL SAG SLOWLY SOUTH INTO THE AREA TONIGHT AND INTO NORTH CAROLINA BY EARLY SATURDAY. THE FRONT WILL STALL OVER THE CAROLINAS OVER THE WEEKEND INTO EARLY NEXT WEEK. LOW PRESSURE WILL MOVE FROM THE GULF COAST INTO THE CAROLINAS ON TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT FRIDAY... WAVE/VORT MOVING INTO SOUTHERN WVA ATTM THE MAIN PLAYER THIS MORNING WITH BANDS OF SHRA/TSRA EXTENDING FROM AROUND THE SMALL COMMA HEAD SOUTH INTO SW VA PER LATEST RADAR TRENDS. LATEST GUIDANCE TAKES THIS IMPULSE NE ALONG THE FRONT INTO NORTH/CENTRAL VA AND GRADUALLY DAMPENS IT THIS AFTERNOON AS THE SURFACE BOUNDARY SAGS IN BY LATE IN THE DAY. EXPECT MUCH OF THE DEEPER CONVECTION TO THE WEST TO WEAKEN PUSHING OUT EAST ACROSS THE MOUNTAINS GIVEN LACK OF EARLY INSTABILITY BUT MAY BE ENOUGH SHRA/CLOUDS TO INHIBIT HEATING THIS AFTERNOON. EXCEPTIONS LIKELY OVER THE FAR SOUTH AND EAST WHERE DOWNSLOPING SEEN OFF MORNING RAOBS SHOULD ALLOW FOR MORE BREAKS. HAVE ALREADY UPDATED TO BUMP POPS TO LIKELY A BIT SOONER FAR WEST WHILE TRIMMING OUT EAST WHERE WILL STILL BE A FEW HOURS PUSHING ANY SHRA OVER THE BLUE RIDGE. LEFT OVERALL LIKELY POPS FOR MOST AREAS LATER IN THE AFTERNOON WHEN COMBO OF WAVE/FRONT AND SOME HEATING SHOULD ALLOW FOR MORE WIDESPREAD SHRA ACROSS THE CWA. TEMPS TRICKY AS EXPECT LITTLE IN THE WAY OF RISES NW EARLY ON WHILE SEEING SOME SUN PIEDMONT AND FAR SOUTH. THEREFORE BUMPED DOWN HIGHS IN THE WEST AND NORTH A FEW DEGREES WHILE LEAVING THE EAST MOSTLY IN THE LOW 80S. PREVIOUS DISCUSSION AS OF 420 AM EDT FRIDAY... COLD FRONT TRAILS FROM LOW IN WESTERN PENNSYLVANIA TO ANOTHER LOW IN WESTERN KENTUCKY. WATER VAPOR LOOP SHOWS A WELL DEFINED SHORT WAVE ASSOCIATED WITH THE KENTUCKY LOW. THIS FEATURE WILL TRACK EAST TODAY...REACHING THE FORECAST AREA THIS AFTERNOON. EXPECT THE FRONT TO REMAIN ALONG A DC TO WESTERN KENTUCKY LINE THROUGH THE DAY WITH A SLIGHT PUSH TO THE SOUTH TONIGHT AFTER THE LOW GOES BY. SIMILAR TO THE PAST COUPLE OF DAYS EXPECT CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE BOUNDARY TODAY AND TONIGHT. RADAR WAS SHOWING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WARM...MOIST AIR MASS AHEAD OF THE FRONT. LATEST RUC AND LOCAL WRF DATA KEPT A MAJORITY OF THE SHOWERS AND THUNDERSTORMS IN THE WESTERN COUNTY WARNING AREA THIS MORNING THEN MOVES A LINE OF THUNDERSTORMS ACROSS THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. HAVE ALIGNED PROBABILITY OF PRECIPITATION TO FOLLOW THIS TIMING AND PLACEMENT. ONCE THE STORMS EXIT THE AREA THIS EVENING...THE CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES OVERNIGHT WITH THE FRONT ENTERING THE NORTHERN AND CENTRAL COUNTY WARNING AREA. CLOUD COVER WILL GREATLY INFLUENCE THE INSTABILITY TODAY AND THE LOCATIONS WITH THE HIGHEST POTENTIAL OF STRONG TO SEVERE STORMS. WITH CLOUDS ALREADY SPREADING INTO THE WESTERN COUNTY WARNING AREA...APPEARS THE BETTER THREAT FOR ANY SEVERE STORMS WILL BE IN THE FOOTHILLS AND PIEDMONT WERE THERE WILL BE MORE HEATING AND BETTER LAPSE RATES. WILL HIGHLIGHT THE SEVERE THREAT FOR THIS REGION IN THE HAZARDOUS WEATHER OUTLOOK. WITH THE FOOTHILLS AND PIEDMONT GETTING MORE SUN THIS MORNING HAVE USE THE WARMER GUIDANCE AS A BASIS FOR AFTERNOON HIGH TEMPERATURES. CLOUDS WILL KEEP HIGHS SLIGHTLY COOLER IN THE WEST. WILL ALSO KEEP MINIMUM TEMPERATURES TONIGHT ON THE MILD SIDE...WITH MUCH OF THE FORECAST AREA STILL ON THE WARM SIDE OF THE FRONT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 AM EDT FRIDAY... AN UPPER LEVEL CLOSED OFF LOW WILL TRACK SOUTH FROM ONTARIO ON SATURDAY TO NORTHWEST PENNSYLVANIA SUNDAY. THIS LOW WILL THEN TRACK NORTHEAST OVER NEW YORK SUNDAY NIGHT. THIS LOW WILL MAINLY INFLUENCE THE AREAS WEATHER BY KEEPING TEMPERATURES NEAR NORMAL ON SATURDAY AND BELOW NORMAL SUNDAY. CAN NOT RULE OUT A STRAY MOUNTAIN SHOWERS AS SHORT WAVES PIVOT AROUND THE LOW AND ACROSS THE APPALACHIANS. MODELS ARE PAINTING SHOWERS ACROSS RNK SOUTH IN THE MORNING...THEN IN THE PIEDMONT DURING THE AFTERNOON. AT FIRST...I DISREGARDED THESE SHOWERS AS THE FRONT IS WELL SOUTH OF THE AREA AND THE SURFACE TO LOW LEVEL FLOW IS NORTHERLY. IN FURTHER DISSECTING THE MODELS...THERE IS AN 85H THETA-E BOUNDARY ALONG THE BLUE RIDGE FOR MUCH OF THE DAY. FURTHERMORE...MID AND UPPER LEVEL JET STRUCTURE WOULD PROMOTE SHOWERS TO FORM...ESPECIALLY IF LOW LEVEL MOISTURE IS SIGNIFICANT ENOUGH. SO I AM CONVINCED SHOWERS WILL DEVELOP ACROSS THE SOUTH AND EAST ON SATURDAY. HOWEVER...THINKING MODELS ARE OVER DONE ON RAINFALL AMOUNTS WITH SOME DRIER AIR WORKING IN FROM THE NORTH. THESE SHOWERS SHOULD FADE OR MOVE EAST OF THE AREA OVERNIGHT. NEIGHBORING OFFICES IN THE EAST HAVE LOW CHANCE POPS FOR SUNDAY. CONSIDERING THE FLIP-FLOP NATURE OF THE MODELS LATELY AND FORECAST COLLABORATION...WILL ALSO HAVE LOW CHANCE POPS ACROSS THE PIEDMONT SUNDAY. ANY SHOWERS WILL BE BRIEF AND THEREFORE LOOKING AT MORE OF A DRY DAY. BY MONDAY MORNING...THE UPPER LEVEL LOW WILL TRACK TO THE NORTHEAST AND HIGH PRESSURE FILLS IN BEHIND IT. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM EDT THURSDAY... GFS IS DEFINITELY TRENDING TOWARD AN ECMWF SOLUTION NOW WITH MUCH LESS AMPLITUDE WITH THE 500MB SHORT WAVE RIDING THROUGH THE UPPER MIDWEST ON TUESDAY. PATTERN WILL ESSENTIALLY EVOLVE FROM A DEEP TROF IN THE EAST ON SUNDAY TO A SPLIT FLOW REGIME BY MIDWEEK. HIGH PRESSURE IS NOW PROGGED TO SET UP SHOP OFF THE COAST AND THIS WILL BRING DEEP MOIST SLY FLOW INTO OUR AREA. ONE SURGE OF MOISTURE WILL ARRIVE WITH A SHORT WAVE ON TUESDAY AND AGAIN ON THURSDAY WITH A BIT OF A BREAK ON WEDNESDAY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AS OF 1245 PM EDT FRIDAY... INITIAL BATCH OF SHOWERS AND ISOLATED STORMS NOW PUSHING OUT TO EAST OF THE BLUE RIDGE WITH GUSTY WINDS ASSOCIATED WITH THE LEADING EDGE OF THE CONVECTION. THIS WILL CONTINUE TO BRING PERIODS OF IFR/MVFR AT KLWB AND PERHAPS KLYH THRU 19Z/3 PM. ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP ACROSS THE EAST WITH SOME OF THIS COVERAGE LIKELY AFFECTING KDAN THIS AFTERNOON. EXPECTING TO REMAIN VFR AT ALL OTHER SITES AS THE REGION BRIEFLY SLIDES INTO A BREAK BETWEEN THE CURRENT WAVE AND THE NEXT UPSTREAM IMPULSE OVER KY. THIS NEXT WAVE WILL COMBINE WITH THE FRONT SINKING SOUTH TO BRING ANOTHER ROUND OF SHRA/TSRA FROM WEST TO EAST LATE THIS AFTERNOON INTO THIS EVENING. FRONT LOOKS TO SLIP THROUGH THE NW LATER TONIGHT...AND PERHAPS REACHING THE VA/NC BORDER OVERNIGHT. LATEST NAM QUITE BULLISH ON BRINGING IN IFR/LIFR FOG AND LOW CIGS BEHIND THE EXITING SHRA THIS EVENING BUT LOOKS OVERDONE OUTSIDE OF SE WVA WHERE HIGHER CONFIDENCE OF SEEING AT LEAST MVFR CIGS/VSBYS TONIGHT. ELSW TRENDED CLOSER TO THE LATEST LAMP DATA WITH A COMP TOWARD THE NAM LATE WHEN A PERIOD OF MVFR/IFR VSBYS/CIGS POSSIBLE AT MOST LOCATIONS EXCLUDING KROA. THE DEEPER MOISTURE ALONG THE FRONT GETS PUSHED INTO THE CAROLINAS ON SATURDAY AND SUNDAY. HOWEVER WITH ANOTHER WAVE RIPPLING ALONG THE FRONT TO THE SOUTH WILL LIKELY BE HARD TO ERODE LOW CIGS OVER THE SOUTH UNTIL SAT AFTERNOON. SOME -RA ALSO POSSIBLE MAINLY AROUND KDAN IN THE MORNING BUT WONT INCLUDE MENTION ATTM WHILE KEEPING VFR CIGS MOST SPOTS UNTIL MID MORNING AND INTO THE AFTERNOON AT KDAN. SHOULD FINALLY SEE CLOUDS AND A RETURN TO VFR SAT NIGHT INTO SUNDAY WITH ONLY SOME RESIDUAL CLOUDS AROUND OUT EAST SAT EVENING FOR NOW. LOW PRESSURE MOVING UP FROM THE GULF WILL LIKELY BRING RAIN AND SUB VFR CONDITIONS LATER MONDAY INTO TUESDAY FOLLOWED BY IMPROVING WEATHER TUESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR WHICH SERVES THE ROANOKE AND SURROUNDING AREA IS TENTATIVELY SCHEDULED TO BE TAKEN DOWN FOR SEVERAL DAYS BEGINNING MONDAY OCTOBER 1ST FOR ITS UPGRADE TO DUAL POLARIZATION TECHNOLOGY. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)... WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THE INSTALLATION. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...AMS/JH SHORT TERM...RCS LONG TERM...MBS AVIATION...AMS/JH/KM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1006 AM EDT FRI SEP 28 2012 .SYNOPSIS... A COLD FRONT FROM WESTERN PENNSYLVANIA TO WESTERN KENTUCKY WILL MOVE SLOWLY SOUTH THIS AFTERNOON THROUGH SATURDAY. THE FRONT WILL STALL OVER THE CAROLINAS ON SUNDAY AND MONDAY. LOW PRESSURE WILL MOVE FROM THE GULF COAST INTO THE CAROLINAS ON TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT FRIDAY... WAVE/VORT MOVING INTO SOUTHERN WVA ATTM THE MAIN PLAYER THIS MORNING WITH BANDS OF SHRA/TSRA EXTENDING FROM AROUND THE SMALL COMMA HEAD SOUTH INTO SW VA PER LATEST RADAR TRENDS. LATEST GUIDANCE TAKES THIS IMPULSE NE ALONG THE FRONT INTO NORTH/CENTRAL VA AND GRADUALLY DAMPENS IT THIS AFTERNOON AS THE SURFACE BOUNDARY SAGS IN BY LATE IN THE DAY. EXPECT MUCH OF THE DEEPER CONVECTION TO THE WEST TO WEAKEN PUSHING OUT EAST ACROSS THE MOUNTAINS GIVEN LACK OF EARLY INSTABILITY BUT MAY BE ENOUGH SHRA/CLOUDS TO INHIBIT HEATING THIS AFTERNOON. EXCEPTIONS LIKELY OVER THE FAR SOUTH AND EAST WHERE DOWNSLOPING SEEN OFF MORNING RAOBS SHOULD ALLOW FOR MORE BREAKS. HAVE ALREADY UPDATED TO BUMP POPS TO LIKELY A BIT SOONER FAR WEST WHILE TRIMMING OUT EAST WHERE WILL STILL BE A FEW HOURS PUSHING ANY SHRA OVER THE BLUE RIDGE. LEFT OVERALL LIKELY POPS FOR MOST AREAS LATER IN THE AFTERNOON WHEN COMBO OF WAVE/FRONT AND SOME HEATING SHOULD ALLOW FOR MORE WIDESPREAD SHRA ACROSS THE CWA. TEMPS TRICKY AS EXPECT LITTLE IN THE WAY OF RISES NW EARLY ON WHILE SEEING SOME SUN PIEDMONT AND FAR SOUTH. THEREFORE BUMPED DOWN HIGHS IN THE WEST AND NORTH A FEW DEGREES WHILE LEAVING THE EAST MOSTLY IN THE LOW 80S. PREVIOUS DISCUSSION AS OF 420 AM EDT FRIDAY... COLD FRONT TRAILS FROM LOW IN WESTERN PENNSYLVANIA TO ANOTHER LOW IN WESTERN KENTUCKY. WATER VAPOR LOOP SHOWS A WELL DEFINED SHORT WAVE ASSOCIATED WITH THE KENTUCKY LOW. THIS FEATURE WILL TRACK EAST TODAY...REACHING THE FORECAST AREA THIS AFTERNOON. EXPECT THE FRONT TO REMAIN ALONG A DC TO WESTERN KENTUCKY LINE THROUGH THE DAY WITH A SLIGHT PUSH TO THE SOUTH TONIGHT AFTER THE LOW GOES BY. SIMILAR TO THE PAST COUPLE OF DAYS EXPECT CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE BOUNDARY TODAY AND TONIGHT. RADAR WAS SHOWING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WARM...MOIST AIR MASS AHEAD OF THE FRONT. LATEST RUC AND LOCAL WRF DATA KEPT A MAJORITY OF THE SHOWERS AND THUNDERSTORMS IN THE WESTERN COUNTY WARNING AREA THIS MORNING THEN MOVES A LINE OF THUNDERSTORMS ACROSS THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. HAVE ALIGNED PROBABILITY OF PRECIPITATION TO FOLLOW THIS TIMING AND PLACEMENT. ONCE THE STORMS EXIT THE AREA THIS EVENING...THE CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES OVERNIGHT WITH THE FRONT ENTERING THE NORTHERN AND CENTRAL COUNTY WARNING AREA. CLOUD COVER WILL GREATLY INFLUENCE THE INSTABILITY TODAY AND THE LOCATIONS WITH THE HIGHEST POTENTIAL OF STRONG TO SEVERE STORMS. WITH CLOUDS ALREADY SPREADING INTO THE WESTERN COUNTY WARNING AREA...APPEARS THE BETTER THREAT FOR ANY SEVERE STORMS WILL BE IN THE FOOTHILLS AND PIEDMONT WERE THERE WILL BE MORE HEATING AND BETTER LAPSE RATES. WILL HIGHLIGHT THE SEVERE THREAT FOR THIS REGION IN THE HAZARDOUS WEATHER OUTLOOK. WITH THE FOOTHILLS AND PIEDMONT GETTING MORE SUN THIS MORNING HAVE USE THE WARMER GUIDANCE AS A BASIS FOR AFTERNOON HIGH TEMPERATURES. CLOUDS WILL KEEP HIGHS SLIGHTLY COOLER IN THE WEST. WILL ALSO KEEP MINIMUM TEMPERATURES TONIGHT ON THE MILD SIDE...WITH MUCH OF THE FORECAST AREA STILL ON THE WARM SIDE OF THE FRONT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 AM EDT FRIDAY... AN UPPER LEVEL CLOSED OFF LOW WILL TRACK SOUTH FROM ONTARIO ON SATURDAY TO NORTHWEST PENNSYLVANIA SUNDAY. THIS LOW WILL THEN TRACK NORTHEAST OVER NEW YORK SUNDAY NIGHT. THIS LOW WILL MAINLY INFLUENCE THE AREAS WEATHER BY KEEPING TEMPERATURES NEAR NORMAL ON SATURDAY AND BELOW NORMAL SUNDAY. CAN NOT RULE OUT A STRAY MOUNTAIN SHOWERS AS SHORT WAVES PIVOT AROUND THE LOW AND ACROSS THE APPALACHIANS. MODELS ARE PAINTING SHOWERS ACROSS RNK SOUTH IN THE MORNING...THEN IN THE PIEDMONT DURING THE AFTERNOON. AT FIRST...I DISREGARDED THESE SHOWERS AS THE FRONT IS WELL SOUTH OF THE AREA AND THE SURFACE TO LOW LEVEL FLOW IS NORTHERLY. IN FURTHER DISSECTING THE MODELS...THERE IS AN 85H THETA-E BOUNDARY ALONG THE BLUE RIDGE FOR MUCH OF THE DAY. FURTHERMORE...MID AND UPPER LEVEL JET STRUCTURE WOULD PROMOTE SHOWERS TO FORM...ESPECIALLY IF LOW LEVEL MOISTURE IS SIGNIFICANT ENOUGH. SO I AM CONVINCED SHOWERS WILL DEVELOP ACROSS THE SOUTH AND EAST ON SATURDAY. HOWEVER...THINKING MODELS ARE OVER DONE ON RAINFALL AMOUNTS WITH SOME DRIER AIR WORKING IN FROM THE NORTH. THESE SHOWERS SHOULD FADE OR MOVE EAST OF THE AREA OVERNIGHT. NEIGHBORING OFFICES IN THE EAST HAVE LOW CHANCE POPS FOR SUNDAY. CONSIDERING THE FLIP-FLOP NATURE OF THE MODELS LATELY AND FORECAST COLLABORATION...WILL ALSO HAVE LOW CHANCE POPS ACROSS THE PIEDMONT SUNDAY. ANY SHOWERS WILL BE BRIEF AND THEREFORE LOOKING AT MORE OF A DRY DAY. BY MONDAY MORNING...THE UPPER LEVEL LOW WILL TRACK TO THE NORTHEAST AND HIGH PRESSURE FILLS IN BEHIND IT. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM EDT THURSDAY... GFS IS DEFINITELY TRENDING TOWARD AN ECMWF SOLUTION NOW WITH MUCH LESS AMPLITUDE WITH THE 500MB SHORT WAVE RIDING THROUGH THE UPPER MIDWEST ON TUESDAY. PATTERN WILL ESSENTIALLY EVOLVE FROM A DEEP TROF IN THE EAST ON SUNDAY TO A SPLIT FLOW REGIME BY MIDWEEK. HIGH PRESSURE IS NOW PROGGED TO SET UP SHOP OFF THE COAST AND THIS WILL BRING DEEP MOIST SLY FLOW INTO OUR AREA. ONE SURGE OF MOISTURE WILL ARRIVE WITH A SHORT WAVE ON TUESDAY AND AGAIN ON THURSDAY WITH A BIT OF A BREAK ON WEDNESDAY. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... AS OF 735 AM EDT FRIDAY... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME MORE WIDESPREAD DURING THE MORNING. AT THE CURRENT SPEED AND DIRECTION THE LINE OF STORMS IN CENTRAL KENTUCKY WILL REACH BLF AROUND 15Z/11AM AND ROA/BCB AROUND 16Z/NOON. HAVE VCSH IN THE LWB AND BCB TAFS FOR THE SHOWERS AHEAD OF THESE STORMS. HRRR...RUC AND LOCAL WRF SHOWED ANOTHER BATCH OF THUNDERSTORMS CROSSING THROUGH THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. THIS WILL BE AHEAD OF A COLD FRONT DRIFTING SLOWLY SOUTH INTO THE REGION. MODERATE CONFIDENCE THAT BLF AND POSSIBLE LWB WILL HAVE MVFR CEILINGS ON THE COOL SIDE OF THE FRONT LATE TONIGHT. THE DEEPER MOISTURE GETS PUSHED INTO THE CAROLINAS ON SATURDAY AND SUNDAY RESULTING IN VFR CONDITIONS AND A LOWER PROBABILITY OF PRECIPITATION. THE CHANCE OF RAIN AND SUB VFR CONDITIONS RETURNS BY TUESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR WHICH SERVES THE ROANOKE AND SURROUNDING AREA IS TENTATIVELY SCHEDULED TO BE TAKEN DOWN FOR SEVERAL DAYS BEGINNING MONDAY OCTOBER 1ST FOR ITS UPGRADE TO DUAL POLARIZATION TECHNOLOGY. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)... WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THE INSTALLATION. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/JH SHORT TERM...RCS LONG TERM...MBS AVIATION...AMS/KM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
743 AM EDT FRI SEP 28 2012 .SYNOPSIS... A COLD FRONT FROM WESTERN PENNSYLVANIA TO WESTERN KENTUCKY WILL MOVE SLOWLY SOUTH TONIGHT AND SATURDAY. THE FRONT WILL STALL OVER THE CAROLINAS ON SUNDAY AND MONDAY. LOW PRESSURE WILL MOVE FROM THE GULF COAST INTO THE CAROLINAS ON TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 420 AM EDT FRIDAY... COLD FRONT TRAILS FROM LOW IN WESTERN PENNSYLVANIA TO ANOTHER LOW IN WESTERN KENTUCKY. WATER VAPOR LOOP SHOWS A WELL DEFINED SHORT WAVE ASSOCIATED WITH THE KENTUCKY LOW. THIS FEATURE WILL TRACK EAST TODAY...REACHING THE FORECAST AREA THIS AFTERNOON. EXPECT THE FRONT TO REMAIN ALONG A DC TO WESTERN KENTUCKY LINE THROUGH THE DAY WITH A SLIGHT PUSH TO THE SOUTH TONIGHT AFTER THE LOW GOES BY. SIMILAR TO THE PAST COUPLE OF DAYS EXPECT CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE BOUNDARY TODAY AND TONIGHT. RADAR WAS SHOWING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WARM...MOIST AIR MASS AHEAD OF THE FRONT. LATEST RUC AND LOCAL WRF DATA KEPT A MAJORITY OF THE SHOWERS AND THUNDERSTORMS IN THE WESTERN COUNTY WARNING AREA THIS MORNING THEN MOVES A LINE OF THUNDERSTORMS ACROSS THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. HAVE ALIGNED PROBABILITY OF PRECIPITATION TO FOLLOW THIS TIMING AND PLACEMENT. ONCE THE STORMS EXIT THE AREA THIS EVENING...THE CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES OVERNIGHT WITH THE FRONT ENTERING THE NORTHERN AND CENTRAL COUNTY WARNING AREA. CLOUD COVER WILL GREATLY INFLUENCE THE INSTABILITY TODAY AND THE LOCATIONS WITH THE HIGHEST POTENTIAL OF STRONG TO SEVERE STORMS. WITH CLOUDS ALREADY SPREADING INTO THE WESTERN COUNTY WARNING AREA...APPEARS THE BETTER THREAT FOR ANY SEVERE STORMS WILL BE IN THE FOOTHILLS AND PIEDMONT WERE THERE WILL BE MORE HEATING AND BETTER LAPSE RATES. WILL HIGHLIGHT THE SEVERE THREAT FOR THIS REGION IN THE HAZARDOUS WEATHER OUTLOOK. WITH THE FOOTHILLS AND PIEDMONT GETTING MORE SUN THIS MORNING HAVE USE THE WARMER GUIDANCE AS A BASIS FOR AFTERNOON HIGH TEMPERATURES. CLOUDS WILL KEEP HIGHS SLIGHTLY COOLER IN THE WEST. WILL ALSO KEEP MINIMUM TEMPERATURES TONIGHT ON THE MILD SIDE...WITH MUCH OF THE FORECAST AREA STILL ON THE WARM SIDE OF THE FRONT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 AM EDT FRIDAY... AN UPPER LEVEL CLOSED OFF LOW WILL TRACK SOUTH FROM ONTARIO ON SATURDAY TO NORTHWEST PENNSYLVANIA SUNDAY. THIS LOW WILL THEN TRACK NORTHEAST OVER NEW YORK SUNDAY NIGHT. THIS LOW WILL MAINLY INFLUENCE THE AREAS WEATHER BY KEEPING TEMPERATURES NEAR NORMAL ON SATURDAY AND BELOW NORMAL SUNDAY. CAN NOT RULE OUT A STRAY MOUNTAIN SHOWERS AS SHORT WAVES PIVOT AROUND THE LOW AND ACROSS THE APPALACHIANS. MODELS ARE PAINTING SHOWERS ACROSS RNK SOUTH IN THE MORNING...THEN IN THE PIEDMONT DURING THE AFTERNOON. AT FIRST...I DISREGARDED THESE SHOWERS AS THE FRONT IS WELL SOUTH OF THE AREA AND THE SURFACE TO LOW LEVEL FLOW IS NORTHERLY. IN FURTHER DISSECTING THE MODELS...THERE IS AN 85H THETA-E BOUNDARY ALONG THE BLUE RIDGE FOR MUCH OF THE DAY. FURTHERMORE...MID AND UPPER LEVEL JET STRUCTURE WOULD PROMOTE SHOWERS TO FORM...ESPECIALLY IF LOW LEVEL MOISTURE IS SIGNIFICANT ENOUGH. SO I AM CONVINCED SHOWERS WILL DEVELOP ACROSS THE SOUTH AND EAST ON SATURDAY. HOWEVER...THINKING MODELS ARE OVER DONE ON RAINFALL AMOUNTS WITH SOME DRIER AIR WORKING IN FROM THE NORTH. THESE SHOWERS SHOULD FADE OR MOVE EAST OF THE AREA OVERNIGHT. NEIGHBORING OFFICES IN THE EAST HAVE LOW CHANCE POPS FOR SUNDAY. CONSIDERING THE FLIP-FLOP NATURE OF THE MODELS LATELY AND FORECAST COLLABORATION...WILL ALSO HAVE LOW CHANCE POPS ACROSS THE PIEDMONT SUNDAY. ANY SHOWERS WILL BE BRIEF AND THEREFORE LOOKING AT MORE OF A DRY DAY. BY MONDAY MORNING...THE UPPER LEVEL LOW WILL TRACK TO THE NORTHEAST AND HIGH PRESSURE FILLS IN BEHIND IT. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM EDT THURSDAY... GFS IS DEFINITELY TRENDING TOWARD AN ECMWF SOLUTION NOW WITH MUCH LESS AMPLITUDE WITH THE 500MB SHORT WAVE RIDING THROUGH THE UPPER MIDWEST ON TUESDAY. PATTERN WILL ESSENTIALLY EVOLVE FROM A DEEP TROF IN THE EAST ON SUNDAY TO A SPLIT FLOW REGIME BY MIDWEEK. HIGH PRESSURE IS NOW PROGGED TO SET UP SHOP OFF THE COAST AND THIS WILL BRING DEEP MOIST SLY FLOW INTO OUR AREA. ONE SURGE OF MOISTURE WILL ARRIVE WITH A SHORT WAVE ON TUESDAY AND AGAIN ON THURSDAY WITH A BIT OF A BREAK ON WEDNESDAY. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 735 AM EDT FRIDAY... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BECOME MORE WIDESPREAD DURING THE MORNING. AT THE CURRENT SPEED AND DIRECTION THE LINE OF STORMS IN CENTRAL KENTUCKY WILL REACH BLF AROUND 15Z/11AM AND ROA/BCB AROUND 16Z/NOON. HAVE VCSH IN THE LWB AND BCB TAFS FOR THE SHOWERS AHEAD OF THESE STORMS. HRRR...RUC AND LOCAL WRF SHOWED ANOTHER BATCH OF THUNDERSTORMS CROSSING THROUGH THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. THIS WILL BE AHEAD OF A COLD FRONT DRIFTING SLOWLY SOUTH INTO THE REGION. MODERATE CONFIDENCE THAT BLF AND POSSIBLE LWB WILL HAVE MVFR CEILINGS ON THE COOL SIDE OF THE FRONT LATE TONIGHT. THE DEEPER MOISTURE GETS PUSHED INTO THE CAROLINAS ON SATURDAY AND SUNDAY RESULTING IN VFR CONDITIONS AND A LOWER PROBABILITY OF PRECIPITATION. THE CHANCE OF RAIN AND SUB VFR CONDITIONS RETURNS BY TUESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR WHICH SERVES THE ROANOKE AND SURROUNDING AREA IS TENTATIVELY SCHEDULED TO BE TAKEN DOWN FOR SEVERAL DAYS BEGINNING MONDAY OCTOBER 1ST FOR ITS UPGRADE TO DUAL POLARIZATION TECHNOLOGY. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)... WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THE INSTALLATION. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...MBS AVIATION...AMS/KM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
438 AM EDT FRI SEP 28 2012 .SYNOPSIS... A COLD FRONT FROM WESTERN PENNSYLVANIA TO WESTERN KENTUCKY WILL MOVE SLOWLY SOUTH TONIGHT AND SATURDAY. THE FRONT WILL STALL OVER THE CAROLINAS ON SUNDAY AND MONDAY. LOW PRESSURE WILL MOVE FROM THE GULF COAST INTO THE CAROLINAS ON TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 420 AM EDT FRIDAY... COLD FRONT TRAILS FROM LOW IN WESTERN PENNSYLVANIA TO ANOTHER LOW IN WESTERN KENTUCKY. WATER VAPOR LOOP SHOWS A WELL DEFINED SHORT WAVE ASSOCIATED WITH THE KENTUCKY LOW. THIS FEATURE WILL TRACK EAST TODAY...REACHING THE FORECAST AREA THIS AFTERNOON. EXPECT THE FRONT TO REMAIN ALONG A DC TO WESTERN KENTUCKY LINE THROUGH THE DAY WITH A SLIGHT PUSH TO THE SOUTH TONIGHT AFTER THE LOW GOES BY. SIMILAR TO THE PAST COUPLE OF DAYS EXPECT CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE BOUNDARY TODAY AND TONIGHT. RADAR WAS SHOWING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WARM...MOIST AIR MASS AHEAD OF THE FRONT. LATEST RUC AND LOCAL WRF DATA KEPT A MAJORITY OF THE SHOWERS AND THUNDERSTORMS IN THE WESTERN COUNTY WARNING AREA THIS MORNING THEN MOVES A LINE OF THUNDERSTORMS ACROSS THE FORECAST AREA BETWEEN 19Z/3PM AND 01Z/9PM. HAVE ALIGNED PROBABILITY OF PRECIPITATION TO FOLLOW THIS TIMING AND PLACEMENT. ONCE THE STORMS EXIT THE AREA THIS EVENING...THE CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES OVERNIGHT WITH THE FRONT ENTERING THE NORTHERN AND CENTRAL COUNTY WARNING AREA. CLOUD COVER WILL GREATLY INFLUENCE THE INSTABILITY TODAY AND THE LOCATIONS WITH THE HIGHEST POTENTIAL OF STRONG TO SEVERE STORMS. WITH CLOUDS ALREADY SPREADING INTO THE WESTERN COUNTY WARNING AREA...APPEARS THE BETTER THREAT FOR ANY SEVERE STORMS WILL BE IN THE FOOTHILLS AND PIEDMONT WERE THERE WILL BE MORE HEATING AND BETTER LAPSE RATES. WILL HIGHLIGHT THE SEVERE THREAT FOR THIS REGION IN THE HAZARDOUS WEATHER OUTLOOK. WITH THE FOOTHILLS AND PIEDMONT GETTING MORE SUN THIS MORNING HAVE USE THE WARMER GUIDANCE AS A BASIS FOR AFTERNOON HIGH TEMPERATURES. CLOUDS WILL KEEP HIGHS SLIGHTLY COOLER IN THE WEST. WILL ALSO KEEP MINIMUM TEMPERATURES TONIGHT ON THE MILD SIDE...WITH MUCH OF THE FORECAST AREA STILL ON THE WARM SIDE OF THE FRONT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 AM EDT FRIDAY... AN UPPER LEVEL CLOSED OFF LOW WILL TRACK SOUTH FROM ONTARIO ON SATURDAY TO NORTHWEST PENNSYLVANIA SUNDAY. THIS LOW WILL THEN TRACK NORTHEAST OVER NEW YORK SUNDAY NIGHT. THIS LOW WILL MAINLY INFLUENCE THE AREAS WEATHER BY KEEPING TEMPERATURES NEAR NORMAL ON SATURDAY AND BELOW NORMAL SUNDAY. CAN NOT RULE OUT A STRAY MOUNTAIN SHOWERS AS SHORT WAVES PIVOT AROUND THE LOW AND ACROSS THE APPALACHIANS. MODELS ARE PAINTING SHOWERS ACROSS RNK SOUTH IN THE MORNING...THEN IN THE PIEDMONT DURING THE AFTERNOON. AT FIRST...I DISREGARDED THESE SHOWERS AS THE FRONT IS WELL SOUTH OF THE AREA AND THE SURFACE TO LOW LEVEL FLOW IS NORTHERLY. IN FURTHER DISSECTING THE MODELS...THERE IS AN 85H THETA-E BOUNDARY ALONG THE BLUE RIDGE FOR MUCH OF THE DAY. FURTHERMORE...MID AND UPPER LEVEL JET STRUCTURE WOULD PROMOTE SHOWERS TO FORM...ESPECIALLY IF LOW LEVEL MOISTURE IS SIGNIFICANT ENOUGH. SO I AM CONVINCED SHOWERS WILL DEVELOP ACROSS THE SOUTH AND EAST ON SATURDAY. HOWEVER...THINKING MODELS ARE OVER DONE ON RAINFALL AMOUNTS WITH SOME DRIER AIR WORKING IN FROM THE NORTH. THESE SHOWERS SHOULD FADE OR MOVE EAST OF THE AREA OVERNIGHT. NEIGHBORING OFFICES IN THE EAST HAVE LOW CHANCE POPS FOR SUNDAY. CONSIDERING THE FLIP-FLOP NATURE OF THE MODELS LATELY AND FORECAST COLLABORATION...WILL ALSO HAVE LOW CHANCE POPS ACROSS THE PIEDMONT SUNDAY. ANY SHOWERS WILL BE BRIEF AND THEREFORE LOOKING AT MORE OF A DRY DAY. BY MONDAY MORNING...THE UPPER LEVEL LOW WILL TRACK TO THE NORTHEAST AND HIGH PRESSURE FILLS IN BEHIND IT. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM EDT THURSDAY... GFS IS DEFINITELY TRENDING TOWARD AN ECMWF SOLUTION NOW WITH MUCH LESS AMPLITUDE WITH THE 500MB SHORT WAVE RIDING THROUGH THE UPPER MIDWEST ON TUESDAY. PATTERN WILL ESSENTIALLY EVOLVE FROM A DEEP TROF IN THE EAST ON SUNDAY TO A SPLIT FLOW REGIME BY MIDWEEK. HIGH PRESSURE IS NOW PROGGED TO SET UP SHOP OFF THE COAST AND THIS WILL BRING DEEP MOIST SLY FLOW INTO OUR AREA. ONE SURGE OF MOISTURE WILL ARRIVE WITH A SHORT WAVE ON TUESDAY AND AGAIN ON THURSDAY WITH A BIT OF A BREAK ON WEDNESDAY. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... AS OF 135 AM EDT FRIDAY... SCATTERED SHOWERS EXTENDED FROM SOUTHERN PENNSYLVANIA TO EASTERN KENTUCKY JUST AHEAD OF A SLOW MOVING COLD FRONT. THESE SHOWERS WERE DISSIPATING AS THEY MOVED EAST BUT STILL ENOUGH COVERAGE TO ADD VCSH TO LWB EARLY THIS MORNING. BY MID MORNING...THE LOW PRESSURE SYSTEM WILL PROGRESS EAST INTO THE LOWER NEW ENGLAND STATES...DRAGGING THE COLD FRONT FURTHER SOUTH ACROSS OUR AREA. ADDITIONAL SHOWER AND ISOLATED THUNDERSTORM ACTIVITY WILL DEVELOP BY THIS AFTERNOON. ANY STRONGER STORMS MAY HAVE MVFR CONDITIONS. THE DEEPER MOISTURE GETS PUSHED INTO THE CAROLINAS ON SATURDAY AND SUNDAY RESULTING IN VFR CONDITIONS AND A LOWER PROBABILITY OF PRECIPITATION. THE CHANCE OF RAIN RETURNS TO THE REGION ON MONDAY AND TUESDAY. && .EQUIPMENT... THE KFCX DOPPLER RADAR WHICH SERVES THE ROANOKE AND SURROUNDING AREA IS TENTATIVELY SCHEDULED TO BE TAKEN DOWN FOR SEVERAL DAYS BEGINNING MONDAY OCTOBER 1ST FOR ITS UPGRADE TO DUAL POLARIZATION TECHNOLOGY. NEIGHBORING DOPPLER RADARS AT STERLING VA (KLWX)... WAKEFIELD VA (KAKQ)...RALEIGH NC (KRAX)...GREENVILLE-SPARTANBURG SC (KGSP)...MORRISTOWN TN (KMRX)...AND CHARLESTON WV (KRLX) WILL CONTINUE TO PROVIDE COVERAGE OVER PARTS OF THE KFCX AREA DURING THE INSTALLATION. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...MBS AVIATION...AMS/KM EQUIPMENT...NF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
643 PM CDT SAT SEP 29 2012 .SHORT TERM...TONIGHT THROUGH TUESDAY 311 PM CDT SAT SEP 29 2012 MAIN FORECAST CONCERNS ARE ON VALLEY FOG POTENTIAL TONIGHT INTO SUNDAY MORNING. FOCUS THEN TURNS TO RAIN CHANCES ON MONDAY. LATEST WATER VAPOR IMAGERY SHOWED A HIGH AMPLITUDE UPPER RIDGE BUILDING INTO THE UPPER MISSISSIPPI RIVER VALLEY. AN ELONGATED UPPER TROUGH EXTENDED FROM QUEBEC SOUTHWEST INTO THE EASTERN GREAT LAKES. A SPLIT FLOW TYPE PATTERN IS EVIDENT ACROSS THE CONUS...WITH A SOUTHERN JET ACROSS THE SOUTHERN UNITED STATES AND A NORTHERN STREAM JET OVER SOUTHERN/CENTRAL PORTIONS OF CANADA. SURFACE ANALYSIS SHOWED TWO AREAS OF HIGH PRESSURE. THE FIRST EXTENDED FROM HUDSONS BAY SOUTHWEST OVER LAKE SUPERIOR. THE SECOND HIGH WAS LOCATED OVER THE IOWA/NEBRASKA BORDER. THESE TWO HIGHS WERE MERGING TOGETHER AND PROVIDING ABUNDANT SUNSHINE ACROSS THE FORECAST AREA. THE HIGH WILL REMAIN IN CONTROL ACROSS THE FORECAST AREA TONIGHT PROVIDING CLEAR SKIES AND CALM TO LIGHT WINDS. FORECAST SOUNDINGS SHOW THE POTENTIAL FOR VALLEY FOG ALONG THE MISSISSIPPI RIVER VALLEY. THE MAIN LIMITING FACTOR APPEARS TO BE A LACK OF SUFFICIENT MOISTURE IN THE LOWER LEVELS...THANKS TO DEEP MIXING THIS AFTERNOON AND PLANT NO LONGER PROVIDING SUFFICIENT EVAPOTRANSPIRATION TO ADD MOISTURE TO THE BOUNDARY LAYER. HOWEVER...WITH THE HIGH OVERHEAD AND THE LONGER NIGHTS THIS TIME OF YEAR...FEEL THAT WE HAVE A BETTER CHANCE OF SEEING THE FOG VERSUS THE PREVIOUS TWO NIGHTS. OFF OF THE NAM...WINDS FROM THE SURFACE THROUGH 500 FEET ARE VERY LIGHT THEN INCREASE SLIGHTLY THROUGH 1200 FT. THIS INCREASE IN WINDS IN THE LOWER LEVELS IS TYPICAL IN THE NAM AND THINKING THAT THIS IS OVERDONE. THE SURFACE TEMPERATURE AND DEWPOINT SPREAD FINALLY GO TO ZERO IN THE 11 TO 12Z TIMEFRAME. THERE ARE ENOUGH SIGNALS TO SUPPORT THE FOG SO WILL BE ADDING PATCHY FOG TO THE FORECAST ALONG THE MISSISSIPPI AND WISCONSIN RIVER VALLEYS. PLAN ON LOW TEMPERATURES RANGING FROM THE LOWER TO MID 30S OVER NORTHERN WISCONSIN TO THE MID 40S ACROSS NORTHEAST IOWA. THE UPPER RIDGE WILL MAKE VERY LITTLE PROGRESS EAST ON SUNDAY AS THE UPPER TROUGH OVER QUEBEC DRIFTS SOUTHWEST AND CLOSES INTO A BROAD UPPER LOW OVER EASTERN LAKE HURON. THIS WILL KEEP THE FORECAST AREA UNDER THE RIDGE THROUGH SUNDAY NIGHT PROVIDING PLEASANT WEATHER. SLIGHTLY COOLER AIR WILL EDGE INTO LOCATIONS ALONG AND EAST OF THE MISSISSIPPI RIVER AS THE SLIDES OVER LAKE HURON. 925 MB TEMPERATURES TO FROM 14Z ON SATURDAY ACROSS NORTH CENTRAL WISCONSIN...TO AROUND 12C BY SUNDAY AFTERNOON. PLAN ON HIGHS RANGING FROM THE MID TO UPPER 60S ACROSS NORTHERN WISCONSIN TO THE LOWER TO MID 70S OVER NORTHEAST IOWA. THE RIDGE WILL BREAK DOWN SUNDAY NIGHT INTO MONDAY AS A TROUGH AND COLD FRONT DIVE SOUTHEAST OUT OF SOUTHERN SASKATCHEWAN AND MANITOBA. MEANWHILE...THE UPPER LOW OVER LAKE HURON WILL LIFT NORTHEAST INTO NEW ENGLAND LATE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT. THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION DURING THE DAY ON MONDAY BRINGING SLIGHT CHANCES FOR RAIN TO THE AREA. FORECAST MODELS ARE NOT PRODUCING MUCH PRECIPITATION AS THE FRONT MOVES THROUGH. FORCING SHOULD BE SUFFICIENT TO PRODUCE LIGHT RAIN...WITH 500-300 MB POTENTIAL VORTICITY ADVECTION OF 15 PVU/S AND WEAK FRONTOGENESIS IN THE 1000 TO 700 MB LAYER. THE FRONTOGENESIS REALLY DIES OUT MONDAY AFTERNOON AND IT APPEARS FORCING REALLY STARTS TO WANE EAST OF THE MISSISSIPPI RIVER DURING THE AFTERNOON HOURS. WOULD NOT EXPECT MORE THAN JUST SOME LIGHT RAIN SHOWERS AS THE FRONT MOVES THROUGH. PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST AND CENTRAL WISCONSIN MAY NOT SEE MORE THAN SOME SPRINKLES. WILL KEEP PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT RANGE DURING THIS TIMEFRAME. PLAN ON A WIND SHIFT FROM THE SOUTHWEST TO NORTHWEST AS THE FRONT MOVES THROUGH. LOOK FOR HIGHS ON MONDAY TO RANGE FROM THE MID TO UPPER 60S ACROSS NORTH CENTRAL WISCONSIN TO THE LOWER 70S OVER NORTHEAST IOWA. HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE REGION IN THE WAKE OF THE FRONT MONDAY NIGHT INTO TUESDAY. THE FORECAST AREA WILL BE IN BETWEEN TWO SYSTEMS...AN APPROACHING TROUGH OVER SOUTHERN ALBERTA/SASKATCHEWAN/MANITOBA...AND AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY. PLAN ON MOSTLY SUNNY SKIES ON TUESDAY WITH HIGHS MAINLY IN THE 70S. .LONG TERM...WEDNESDAY THROUGH SATURDAY 311 PM CDT SAT SEP 29 2012 FORECAST MODELS ARE LEANING TOWARD A MORE ACTIVE AND COOLER PATTERN FOR THE LAST HALF OF THE WORK WEEK. WEDNESDAY LOOKS TO BE THE LAST WARM DAY IN THE EXTENDED PERIOD AHEAD OF STRONG COLD FRONT PUSHING OUT OF SOUTHERN CANADA ACROSS THE DAKOTAS. THE COLD FRONT IS EXPECTED TO EDGE INTO THE AREA LATE WEDNESDAY INTO THURSDAY AS A SHORTWAVE MOVES EAST ACROSS THE DAKOTAS AND LIFTS NORTHEAST INTO WESTERN ONTARIO. THE TRAJECTORY OF THE TROUGH AND DEEPENING LOW OVER WESTERN ONTARIO WILL KEEP A BAROCLINIC ZONE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY INTO FRIDAY. THE BAROCLINIC ZONE WILL INTERACT WITH A SERIES OF EMBEDDED SHORTWAVES IN SOUTHWEST FLOW ALOFT. THIS INTERACTION WILL PRODUCE CHANCES FOR RAIN SHOWERS WEDNESDAY NIGHT INTO THURSDAY. A BROAD UPPER TROUGH WILL SETTLE INTO THE AREA LATE THURSDAY NIGHT INTO FRIDAY WITH COLDER AIR SPILLING INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE RAIN MAY MIX WITH OR CHANGE OVER TO SNOW LATE THURSDAY NIGHT INTO FRIDAY MORNING AS TEMPERATURES PLUMMET INTO THE 30S. SLIGHT RAIN CHANCES WILL CONTINUE INTO FRIDAY NIGHT ALONG AND NORTH OF INTERSTATE 94 WITH CYCLONIC FLOW IN PLACE. A FEW SNOW FLAKES MAY MIX IN LATE IN THE NIGHT. SURFACE HIGH PRESSURE LOOKS TO BUILD INTO THE AREA ON SATURDAY. PLAN ON HIGHS ONLY THE UPPER 40S TO LOWER 50S ON SATURDAY UNDER MOSTLY SUNNY SKIES. && .AVIATION...TONIGHT AND SUNDAY 643 PM CDT SAT SEP 29 2012 FOR TONIGHT...HIGH PRESSURE WILL PROVIDE CLEAR SKIES AT BOTH TAF SITES. THE ONLY QUESTION IS WHETHER THERE WILL BE ENOUGH OF A RECOVERY IN THE DEW POINTS FOR THE POSSIBILITY OF SOME SHALLOW GROUND FOG AT KLSE. THE NAM/WRF SOUNDING WOULD SUGGEST THAT THIS WOULD BE A POSSIBILITY. MEANWHILE THE GFS AND RAP WOULD SAY NO. SINCE THERE IS STILL A BIT OF UNCERTAINTY...LEFT THE BCFG IN THE TAF FOR NOW. WILL WATCH THE DEW POINTS DURING THE NEXT 4 HOURS AND SEE WHETHER THERE IS ANY RECOVERY. FOR SUNDAY...A SCATTERED TO BROKEN DECK OF CIRRUS WILL MOVE INTO BOTH TAF SITES DURING THE AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... 311 PM CDT SAT SEP 29 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
354 AM CDT SUN SEP 30 2012 .DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * LAKE EFFECT MVFR CIGS PROBABLE IN THE COUPLE HOURS AFTER DAYBREAK AND LASTING INTO EARLY AFTERNOON...WITH A SMALL CHC FOR THEM TO BE NEAR 1700 FT AT ONSET. * NORTHEAST WINDS INCREASING IN SPEED SOON AFTER DAYBREAK. /DISCUSSION...UPDATED 06Z... THE COOL FRONT WHICH MOVED THROUGH THE TERMINALS LAST EVE WILL CONTINUE TO WORK SOUTH TOWARD THE OHIO RIVER VALLEY. COLD AIR ADVECTION ON NORTHEAST WINDS IN ITS WAKE WILL HELP TO STEEPEN LAPSE RATES OVER WARM LAKE MICHIGAN. CLOUDS ARE LIKELY TO DEVELOP ACROSS THE WESTERN HALF OF THE LAKE TOWARD DAYBREAK AND MOVE INTO NORTHEAST IL AND LIKELY NORTHWEST IN DURING THE MORNING HOURS. THESE WILL LIKELY BE IN THE MVFR CATEGORY...ESPECIALLY AT ONSET...AND THEN VERY SLOWLY LIFT TOWARD LATE MORNING INTO THE AFTERNOON. THESE DO LOOK TO BE PRETTY THIN...UNDER 1500 FT IN DEPTH...WHICH SHOULD FAVOR SCATTERING IN THE AFTERNOON. WITH THE WIND DIRECTION FROM THE NORTHEAST OFF OF LAKE MICHIGAN...OCCASIONAL GUSTS ARE FAVORED FROM MID-MORNING INTO THE AFTERNOON. SPEEDS WILL DIMINISH TONIGHT AS WEAK RIDGING MOVES INTO THE GREAT LAKES. WITH STILL GENERALLY COOL AIR OVER THE LAKE...FEW TO SCT LAKE GENERATED CLOUDS MAY TRY TO EXPAND SLIGHTLY TONIGHT. BUT LESS IN THE WAY OF AN ADVECTION COMPONENT MAY KEEP ANY OFFSHORE. //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM CONFIDENCE IN 2000-3500 FT CIGS OCCURRING. HIGHEST CONFIDENCE BETWEEN 15Z-17Z. * HIGH CONFIDENCE IN WIND TRENDS. //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY THROUGH WEDNESDAY...GENERALLY VFR. THURSDAY INTO FRIDAY...CHANCE OF SHOWERS AND MVFR CIGS. MTF/IZZI && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
343 AM CDT SUN SEP 30 2012 .DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LAKE EFFECT MVFR CIGS PROBABLE NEAR OR SOON AFTER DAYBREAK...WITH A CHC FOR THEM TO BE NEAR 1700 FT AT ONSET. * NORTHEAST WINDS INCREASING IN SPEED SOON AFTER DAYBREAK. //DISCUSSION...UPDATED 06Z... THE COOL FRONT WHICH MOVED THROUGH THE TERMINALS LAST EVE WILL CONTINUE TO WORK SOUTH TOWARD THE OHIO RIVER VALLEY. COLD AIR ADVECTION ON NORTHEAST WINDS IN ITS WAKE WILL HELP TO STEEPEN LAPSE RATES OVER WARM LAKE MICHIGAN. CLOUDS ARE LIKELY TO DEVELOP ACROSS THE WESTERN HALF OF THE LAKE TOWARD DAYBREAK AND MOVE INTO NORTHEAST IL AND LIKELY NORTHWEST IN DURING THE MORNING HOURS. THESE WILL LIKELY BE IN THE MVFR CATEGORY...ESPECIALLY AT ONSET...AND THEN VERY SLOWLY LIFT TOWARD LATE MORNING INTO THE AFTERNOON. THESE DO LOOK TO BE PRETTY THIN...UNDER 1500 FT IN DEPTH...WHICH SHOULD FAVOR SCATTERING IN THE AFTERNOON. WITH THE WIND DIRECTION FROM THE NORTHEAST OFF OF LAKE MICHIGAN...OCCASIONAL GUSTS ARE FAVORED FROM MID-MORNING INTO THE AFTERNOON. SPEEDS WILL DIMINISH TONIGHT AS WEAK RIDGING MOVES INTO THE GREAT LAKES. WITH STILL GENERALLY COOL AIR OVER THE LAKE...FEW TO SCT LAKE GENERATED CLOUDS MAY TRY TO EXPAND SLIGHTLY TONIGHT. BUT LESS IN THE WAY OF AN ADVECTION COMPONENT MAY KEEP ANY OFFSHORE. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN MVFR CIGS OCCURRING. HIGHEST CONFIDENCE BETWEEN 14Z-17Z. * HIGH CONFIDENCE IN WIND TRENDS. //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY THROUGH WEDNESDAY...GENERALLY VFR. THURSDAY INTO FRIDAY...CHANCE OF SHOWERS AND MVFR CIGS. MTF/IZZI && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 AM CDT SUN SEP 30 2012 .SHORT TERM /TODAY/... SURFACE RIDGE AXIS WILL REMAIN IN PLACE ACROSS IOWA WITH LITTLE CHANGE IN THE FORECAST. SOME HIGH CLOUDS WILL DRIFT OVERHEAD WHICH MAY TAKE AWAY SOME INSOLATION TODAY ALONG WITH SLIGHTLY MODIFIED 850MB TEMPERATURES...THEREFORE HIGHS TODAY LIKELY A DEGREE OR TWO LESS THAN SATURDAY. THREAT OF PRECIPITATION REMAINS NIL WITH VERY LIMITED MOISTURE AND FORCING. .LONG TERM /TONIGHT THROUGH SATURDAY/... SEVERAL WEATHER SYSTEMS ARE SET TO IMPACT THE REGION IN THE COMING SEVEN DAYS...INCLUDING A DRAMATIC SHIFT IN TEMPERATURES TOWARD THE END OF THE WEEK. THE RIDGING THAT HAS BROUGHT US QUIET AND MILD WEATHER THIS WEEKEND WILL BE SLOWLY PINCHED OFF TODAY BETWEEN A 500 MB CUTOFF LOW OVER ARKANSAS AND A SHORTWAVE MOVING ACROSS SOUTHERN CANADA. THE WEAKNESS IN THE RIDGE CREATED BY THE SOUTHERN LOW WILL ALLOW THE NORTHERN SHORTWAVE TO DIVE SOUTHEASTWARD TONIGHT AND MONDAY...PUSHING A SURFACE TROUGH ACROSS OUR AREA ON MONDAY. THE PASSAGE OF THE NORTHERN WAVE WILL BE ACCOMPANIED BY A BRIEF SHOT OF LIFT HOWEVER THERE IS SUBSTANTIAL DRY AIR IN THE LOWER LEVELS INDICATED BY FORECAST SOUNDINGS. HAVE THUS INCLUDED SLIGHT CHANCE POPS ON MONDAY BUT ANY RAINFALL THAT DOES OCCUR WILL BE SPOTTY AND VERY LIGHT. BEHIND THE SURFACE TROUGH A PACIFIC HIGH WILL BUILD IN...WITH AN AIRMASS ONLY A LITTLE COOLER THAN WHAT PRECEDED THE FRONT AND HIGHS WELL INTO THE 70S FORECAST ON MONDAY AND TUESDAY. MEANWHILE THE WAVE THAT MOVED BY ON SUNDAY NIGHT/MONDAY WILL PHASE WITH THE CUTOFF LOW TO THE SOUTH...RESULTING IN AN ELONGATED 500 MB TROUGH THAT WILL LINGER FROM THE OZARKS UP TO THE GREAT LAKES FROM MONDAY NIGHT THROUGH TUESDAY BEFORE IT FINALLY MOVES DOWNSTREAM ON TUESDAY NIGHT. BY WEDNESDAY MORNING THE FIRST 500 MB TROUGH WILL BE MOVING EASTWARD ACROSS THE OHIO RIVER VALLEY...WHILE AT THE SAME TIME A MORE POTENT NORTHERN STREAM TROUGH WILL BE WHEELING FROM SOUTHWESTERN CANADA INTO THE NORTHERN U.S. ROCKIES. BETWEEN THESE TWO SYSTEMS A BRIEF SHOT OF RIDGING WILL BUILD ACROSS THE MIDWEST AND IOWA ON WEDNESDAY. AT THE SURFACE THIS WILL BE REFLECTED BY MODEST SOUTHERLY FLOW AND MUCH WARMER TEMPERATURES. HAVE TRENDED AFTERNOON HIGHS UP BY SEVERAL DEGREES ON WEDNESDAY...INTO THE LOWER 80S ACROSS MUCH OF THE CWA AND WE COULD EVEN SEE SOME MID-80S ESPECIALLY ACROSS OUR SOUTHERN COUNTIES. ANY LOVERS OF WARM WEATHER SHOULD BREATHE DEEP ON WEDNESDAY HOWEVER...AS THE TROUGH MOVING OVER THE NORTHERN ROCKIES WILL SUBSEQUENTLY DIG EASTWARD AND PUSH A POWERFUL SURFACE COLD FRONT ACROSS IOWA ON WEDNESDAY NIGHT/THURSDAY. THERE REMAIN SOME DIFFERENCES IN TIMING OF FRONTAL PASSAGE BETWEEN THE VARIOUS MODELS WHICH PRECLUDES HIGHER THAN 30-40 POPS FOR NOW...HOWEVER THERE IS A GOOD SIGNAL FOR SOME SHOWERS AND UNANIMOUS SIGNS OF A MUCH COOLER AIRMASS BEHIND THE FRONT THAT WILL DROP TEMPERATURES SIGNIFICANTLY BY THURSDAY OR THURSDAY NIGHT. THEREAFTER...SEVERAL SUCCEEDING 500 MB SHORTWAVES WILL CARVE OUT A LARGE BOWL OF CYCLONIC FLOW OVER THE NORTHERN U.S. THAT WILL KEEP US COOL AT LEAST THROUGH THE WEEKEND WITH HIGHS ACROSS IOWA ONLY IN THE 50S FROM FRIDAY THROUGH SUNDAY. DURING THIS TIME FRAME WE MAY SEE ONE OR MORE SHOTS OF LIGHT SHOWERS AS THE AFOREMENTIONED SHORTWAVES MOVE OVERHEAD...HOWEVER MOISTURE WILL BE LIMITED AND ONLY ISOLATED/LIGHT RAINFALL IS EXPECTED AT THIS TIME. && .AVIATION...30/06Z HIGH PRESSURE WILL BE IN PLACE THROUGH THE PERIOD WITH MAINLY VFR CONDITIONS AND CLEAR SKIES. ONLY EXCEPTION APPEARS TO BE AT KOTM...AND IS ALSO SHOWING UP AT KAMW...WHERE MVFR HZ VSYBS HAVE DEVELOPED. ONLY EXPLANATION SEEMS TO BE HARVEST RESIDUE TRAPPED UNDER STRONG INVERSION AS DEPICTED IN RAP FORECAST SOUNDINGS. WINDS WILL BE LIGHT WITH ONLY SLIGHT INCREASE DURING PEAK HEATING SUN. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...COGIL LONG TERM...LEE AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1200 AM CDT SUN SEP 30 2012 .SHORT TERM /TONIGHT/... RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE STATE TONIGHT HOWEVER MODIFICATION OF THE AIRMASS ASSOCIATED WITH IT IS IN PROGRESS. SFC THETA-E VALUES WILL TREND A BIT HIGHER TONIGHT THAN THE PREVIOUS NIGHT. THE HIGHER SFC THETA-E VALUES IN ADDITION TO WARMING IN THE 950-925 MB LAYER...WHICH WILL BE THE BASE OF THE OVERNIGHT INVERSION...WILL HELP HOLD TEMPERATURES UP A FEW DEGREES TONIGHT FROM THIS MORNINGS LOWS. OTHERWISE EXPECT MOSTLY CLEAR SKIES AND LIGHT WINDS TO PREVAIL. .LONG TERM /SUNDAY THROUGH SATURDAY/... THE RIDGING OVER THE MIDWEST BEGINS TO BREAK DOWN ON SUNDAY WITH THE ENTRANCE OF A DECENT SHORT WAVE OVER CANADA. MEANWHILE AN UPPER LOW OVER TX/OK/LA DEEPENS. THE SURFACE REFLECTION OF THE NORTHERN SYSTEM IN THE FORM OF A COLD FRONT WILL BE PUSHING OUT OF THE NORTHERN PLAINS LATE SUNDAY AND SUNDAY NIGHT THEN ACROSS THE UPPER MIDWEST MONDAY. FORECAST SOUNDING ARE DRY THROUGH 700 MB THOUGH THERE IS SOME FORCING WITH THE FRONT...WHICH DIMINISHES AS IT MOVES EAST ACROSS CENTRAL IOWA. MY CONFIDENCE IS NOT HIGH ENOUGH TO GO WITH POPS AND MENTION SHOWERS THOUGH THERE IS MOISTURE AT 700 MB AND THE FORCING WITH THE FRONT SUGGESTS THAT WE COULD SEE SPRINKLES. TEMPERATURES MONDAY WILL BE A LITTLE TRICKY WITH A WARM SOUTHERLY FLOW IN PLACE ACROSS THE EAST/SOUTHEAST AND THE COLD FRONT PUSHING INTO THE NORTHWEST IN THE MORNING. THE AIR IS NOT REALLY COLD BEHIND THE FRONT SO I TEMPS SHOULD REMAIN IN THE 70S WITH THE WARMEST READINGS FAR SOUTH. RIDGING BUILDS BACK INTO THE UPPER MIDWEST MONDAY NIGHT THROUGH WEDNESDAY FOR MORE DRY CONDITIONS WITH WARMING TEMPERATURES. HIGHS SHOULD BE BACK AROUND 80 IN THE FAR SOUTH WITH MID 70S OR SO NORTH. MODELS VARY ON THE STRENGTH OF THE RIDGE BUILDING BACK SO I WAS CONSERVATIVE IN TEMPS BUT OF THE EURO IS RIGHT THEN THE ENTIRE CWA WILL BE A FEW DEGREES ABOVE WHAT I CURRENTLY HAVE. THE EURO IS CURRENTLY THE OUTLIER SO I DID NOT PUT ALL MY CONFIDENCE IN THAT MODEL JUST YET. THEN FOR THE GAME CHANGER SYSTEM WEDNESDAY NIGHT AND THURSDAY. A DEEPENING LOW OVER CANADA CARVES OUT A TROUGH OVER THE MIDWEST AND A STRONG COLD FRONT PUSHES IN OVERNIGHT WEDNESDAY NIGHT INTO THURSDAY MORNING. ONCE AGAIN SOUNDINGS ARE SHOWING A DECIDED LACK OF MOISTURE WITH THIS SYSTEM BUT FORCING IS STRONGER AND MORE FOCUSED ALONG THE BOUNDARY SO I AM MORE CONFIDENT THAT CHANCE POPS ARE WARRANTED FOR THIS PERIOD. PRECIP SHOULD BE IN THE FORM OF RAIN BUT TEMPS WILL DROP TO FREEZING OR BELOW NORTH. THE FORCING WITH THE FRONT HOWEVER WILL BE DONE AND PRECIP SHOULD BE OVER BEFORE IT SWITCHES TO SNOW. IF HOWEVER THE COLDER AIR SURGES IN QUICKER OR THE FORCING LASTS LONGER WE MAY NEED TO ADDRESS AT LEAST A RAIN TO SNOW WORDING WEDNESDAY NIGHT. AT THIS POINT THOUGH IT APPEARS UNLIKELY. THIS WILL CHANGE TO TEMP TRENDS OVER THE UPPER MIDWEST INTO NEXT WEEK. THE UPPER FLOW GOES ZONAL BUT A LARGE SURFACE HIGH OF CANADIAN ORIGIN PARKS ITSELF OVER THE NORTHERN PLAINS/UPPER MIDWEST KEEPING SOME VERY COLD AIR IN PLACE. HIGHS IN THE 70S WILL BE REPLACED WITH HIGHS IN THE 50S AND LOWS IN THE 40S WITH LOWS IN THE 30S. && .AVIATION...30/06Z HIGH PRESSURE WILL BE IN PLACE THROUGH THE PERIOD WITH MAINLY VFR CONDITIONS AND CLEAR SKIES. ONLY EXCEPTION APPEARS TO BE AT KOTM...AND IS ALSO SHOWING UP AT KAMW...WHERE MVFR HZ VSYBS HAVE DEVELOPED. ONLY EXPLANATION SEEMS TO BE HARVEST RESIDUE TRAPPED UNDER STRONG INVERSION AS DEPICTED IN RAP FORECAST SOUNDINGS. WINDS WILL BE LIGHT WITH ONLY SLIGHT INCREASE DURING PEAK HEATING SUN. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...DONAVON LONG TERM...FAB AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1129 PM MDT SAT SEP 29 2012 .UPDATE... ISSUED AT 745 PM MDT SAT SEP 29 2012 JUST COMPLETED AN UPDATE THROUGH TOMORROW. LATEST MODELS CONFIRMED BY SURFACE ANALYSIS. SURFACE TROUGH STILL CLOSE TO THE FRONT AND MODELS HAVE THIS TOO FAR EAST. THE RUC FOLLOWED BY THE HRRR AND NAM WERE THE BEST MODELS WITH THIS. AS A RESULT WINDS WILL STAY FROM A SOUTH TO SOUTHEAST DIRECTION WELL INTO THE NIGHT ALLOWED AN INCREASE IN BLYR MOISTURE. BECAUSE OF ALL THIS INCREASED CLOUD COVER THROUGH THE NIGHT TO ACCOUNT FOR STRATUS AND ALSO INSERTED AREAS OF FOG OVER MOST OF THE AREA BEGINNING AT 06Z. ALSO ADJUSTED THE WINDS AND DEWPOINTS ACCORDING THE RUC...NAM...AND HRRR. CURRENTLY LITTLE IF ANY PRECIPITATION OCCURRING CLOSE TO THE FORECAST AREA. 00Z SOUNDINGS AND SATELLITE SHOW DEEP DRY LAYER AND LITTLE IF ANY LIFT ACROSS THE AREA AT THIS TIME. LIFT FROM INCOMING SURFACE TROUGH AND SHORTWAVE TROUGH AND DEEPER MOISTURE INCREASES AFTER 06Z...ESPECIALLY BY LATER IN THE NIGHT. ALSO ELEVATED CAPE INCREASES DRAMATICALLY WITH CINH THAT CAN BE OVERCOME. SO CONFINED A SLIGHT CHANCE OF THUNDERSTORMS UNTIL AFTER 06Z AND TO THE WEST OF THE COLORADO BORDER. THEN INCREASED THUNDERSTORM CHANCES AFTER 12Z AND GRADUALLY PROGRESS THIS ACROSS THE FORECAST AREA THROUGH THE DAY. && .SHORT TERM...(TONIGHT THROUGH SUNDAY) ISSUED AT 142 PM MDT SAT SEP 29 2012 NORTHWEST FLOW WILL BRING A SHORTWAVE INTO THE REGION LATE TONIGHT AND SUNDAY. A SURFACE TROUGH IN EASTERN COLORADO TONIGHT WILL SHIFT EAST ACROSS NORTHWEST KANSAS SUNDAY. SHORTWAVE TIMING WILL KEEP POPS NIL ACROSS MOST OF THE FA WITH EXCEPTION OF EASTERN COLORADO THIS EVENING. EASTERN COLORADO WILL BE THE FIRST ZONES TO HAVE ANY CHANCE THIS EVENING. WEAK DYNAMICS WILL THEN SPREAD INTO NORTHWEST KANSAS/EXTREME SOUTHWEST NEBRASKA AFTER 06Z SUNDAY. AFTER A MORNING LULL, THERE WILL BE A CHANCE OF THUNDERSTORMS ACROSS NORTHWEST KANSAS SUNDAY AFTERNOON GENERALLY EAST OF GOODLAND. BOUNDARY LAYER RH GETS HIGH ENOUGH TO SUPPORT PATCHY FOG OVER THE SOUTHEAST ZONES LATE TONIGHT. TEMPERATURES TONIGHT WILL FALL TO THE LOWER 50S. HIGHS SUNDAY WILL BE IN THE UPPER 70S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 220 PM MDT SAT SEP 29 2012 THE 12Z GFS AND ECMWF HAVE SLOWED THE PRE-FRONTAL SURFACE TROUGH DOWN FOR SUNDAY TO WHAT THE NAM HAS BEEN SHOWING THE LAST COUPLE OF DAYS. WITH THE LATEST GEFS MEMBERS ALSO SLOWING THE TROUGH DOWN WILL KEEP HIGHER PRECIP. CHANCES OVER THE EASTERN 1/3 OF THE AREA SUNDAY EVENING. EXTENDED THE SLIGHT CHANCES OVER THE EAST PAST MIDNIGHT DUE TO THE SLOWER TROUGH PASSAGE. MEANWHILE A COOLER AIR MASS WILL BEGIN TO MOVE INTO THE AREA DURING THE OVERNIGHT HOURS. MONDAY DRIER AIR MOVES INTO THE AREA SO WILL CONTINUE TO LEAVE THE FORECAST DRY DESPITE AN UPPER LEVEL SHORT WAVE TROUGH MOVING THROUGH DURING THE AFTERNOON. SURFACE WINDS WILL STRENGTHEN DURING THE AFTERNOON AS WINDS OF 20 TO 30 KTS MIX DOWN FROM 700MB. MONDAY NIGHT WILL ALSO BE DRY AS A SURFACE AND UPPER LEVEL RIDGE MOVE THROUGH AND POINT SOUNDINGS CONTINUE TO DRY OUT. FOR THE TUESDAY THROUGH SATURDAY PERIOD MODELS ARE COMING INTO BETTER AGREEMENT REGARDING THE TIMING OF THE UPPER LEVEL TROUGH DROPPING DOWN FROM CANADA INTO THE CENTRAL PLAINS. CURRENT MODEL RUNS HAVE THE TROUGH PASSING THROUGH THE AREA WEDNESDAY NIGHT...WITH THE MAJORITY OF THE LIFT WITH THE TROUGH NORTH OF THE AREA. WITH 1000-500MB RELATIVE HUMIDITY INCREASING AS THE TROUGH MOVES THROUGH...HAVE INTRODUCED PRECIP. CHANCES ALONG/NORTH OF THE NEBRASKA LINE. THE TROUGH BROADENS DURING THE LATTER HALF OF THE WORK WEEK AS ANOTHER SHORT WAVE TROUGH DIVES SOUTH ACROSS THE PLAINS...PASSING OVER THE AREA SATURDAY. MODELS CURRENTLY PLACE THE MAJORITY OF THE 1000-500MB RELATIVE HUMIDITY JUST NORTH OF THE AREA...SO WILL KEEP PRECIP. CHANCES IN THE SILENT CATEGORY FOR NOW. A STRONG COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY NIGHT. BELOW NORMAL TEMPERATURES CAN BE EXPECTED AFTER WEDNESDAY AS THE COOLER AIR MASS REMAINS OVER THE AREA. SOME LOCATIONS...ESPECIALLY THOSE IN LOW LYING AREAS MAY SEE FROST FRIDAY AND SATURDAY MORNING AS LOW TEMPERATURES APPROACH THE MID 30S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1122 PM MDT SAT SEP 29 2012 NOT TOO MUCH HAS CHANGED FROM EARLIER THINKING. STILL A LOT OF UNCERTAINTY WITH A NUMBER PARAMETERS. MODELS HAVE BACKED OFF ON COVERAGE/TIMING OF PRECIPITATION...STRATUS/FOG...AND QUICKENED THE ARRIVAL OF THE SURFACE TROUGH. HOWEVER...CURRENT SURFACE OBSERVATIONS ARE INDICATING FOG HAS BEGUN TO DEVELOP TO OUR SOUTH AND SURFACE TROUGH IS STILL WELL TO THE WEST. 88D SHOWS THAT RETURNS HAVE INCREASED A LITTLE TO THE NORTHWEST OF OUR FORECAST AREA. SO HAVE ONLY MADE MINOR ADJUSTMENTS TO THE TAFS FROM THE 00Z ISSUANCE. EXPECT MVFR CONDITIONS UNTIL THE SURFACE TROUGH AND PRECIPITATION ARRIVES/BEGINS. DUE TO THAT UNCERTAINTY KEPT ONLY THE VCTS MENTION. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...FS LONG TERM...JTL AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
437 AM EDT SUN SEP 30 2012 .SYNOPSIS... A COLD UPPER LEVEL LOW WILL BRING SHOWERS AND ISOLATED THUNDERSTORMS TO THE UPPER OHIO VALLEY TODAY. HIGH PRESSURE WILL FOLLOW WITH A DRY BREAK MONDAY BEFORE A LOW PRESSURE SYSTEM...COMING SLOWLY NORTH FROM LOUISIANA...BRINGS SHOWERS MONDAY NIGHT INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HAVE ADDED ISOLATED THUNDERSTORMS TO THE INCREASING COVERAGE OF SHOWERS ACROSS THE UPPER OHIO VALLEY TODAY. RECENT RAP MODEL OUTPUT SHOWS H5 TEMPERATURES AS COLD AS -24C PASSING THROUGH AT LEAST WESTERN PENNSYLVANIA...IN ASSOCIATION WITH THE COLD UPPER LEVEL LOW CENTER THAT WILL BE SWINGING THROUGH THE UPPER OHIO VALLEY INTO LATE AFTERNOON. THERE CAN BE BRIEF EPISODES OF SMALL HAIL/GRAUPEL/ BUT COVERAGE TOO RESTRICTED TO CONFIDENTLY MENTION. HAVE KEPT MENTION OF PATCHY FOG PER RECENT SURFACE DATA...BUT EXPECT FOG TO DISSIPATE BEFORE 9 AM. FORECASTED HIGH TEMPERATURES TODAY TO BE UP TO 5 DEGREES COLDER THAN NORMAL PER RECENT GFS AND NAM MOS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... PER RECENT SREF AND NAM MODEL OUTPUT...THAT SHOW A FASTER UPPER LOW CENTER EXIT EAST...HAVE ENDED SHOWER CHANCES EARLIER THIS EVENING. WITH CLOUDS LIKEWISE DECREASING FASTER...CONCUR WITH NAM MODEL PROFILES THAT NOCTURNAL RADIATIONAL COOLING SHOULD PROMOTE PATCHY FOG LATE TONIGHT. EASTBOUND HIGH PRESSURE SHOULD PROVIDE A DRY BREAK FOR MOST OF DAYTIME MONDAY. THEN SREF MODEL OUTPUT SHOWS A LOW PRESSURE SYSTEM...COMING SLOWLY NORTH FROM LOUISIANA...WILL LIKELY PROVIDE THE UPPER OHIO VALLEY WITH SHOWERS MONDAY NIGHT AND TUESDAY. A TRAILING UPPER LEVEL TROUGH MAY CONTINUE A CHANCE OF SHOWERS TUESDAY NIGHT AND DAYTIME WEDNESDAY. PER SPC CONVECTIVE OUTLOOK AND NAM MODEL PROFILES...HAVE ADDED MENTION OF A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON. FORECASTED TEMPERATURES TO CONTINUE COOLER THAN NORMAL MONDAY...BUT THEN WARM TO AS MUCH AS 7 TO 10 DEGREES ABOVE NORMAL TUESDAY AND WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... THE UPPER LOW PUSHES INTO NEW YORK STATE BY WEDNESDAY EVENING...ENDING THE SHOWERS ACROSS THE FORECAST AREA. HIGH PRESSURE BUILDING INTO THE DISTRICT THURSDAY WILL BRING DRY WEATHER INTO THURSDAY NIGHT. A WEAK COLD FRONT PASSING ACROSS THE DISTRICT FRIDAY WILL BRING A CHANCE OF SHOWERS. HIGH PRESSURE BEHIND THE FRONT WILL BRING A RETURN OF DRY WEATHER FOR SATURDAY. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... GENERAL VFR CONDITIONS THROUGH MID-MORNING WITH BKN-OVC STRATOCU AND SCT SHOWERS/STORMS. THERE WILL BE PATCHY MVFR FOG THROUGH DAWN AT THE USUAL PORTS. LARGE UL SYSTEM WILL ROTATE THROUGH THE UPPER OHIO VALLEY THIS AFTERNOON. THIS WILL KEEP IN CLOUDS AND THE RISK FOR SHOWERS/STORMS. FOR FORECAST...WILL GO WITH VFR CIGS IN THE SOUTH...WHILE MVFR CIGS ARE POSSIBLE TO THE NORTH. A SHOWER/STORM IS POSSIBLE AT ANY TIME TODAY...SO WILL INCLUDE THE MENTION OF NON-RESTRICTIVE SHOWERS AT ALL PORTS UNTIL LATE AFTERNOON. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... SKIES WILL CLEAR TONIGHT...WITH POSSIBLE PATCHY IFR FOG AND STRATUS TOWARD DAWN ON MON. GENERAL VFR RETURNS FOR DAYTIME MONDAY...BUT A LOW PRESSURE SYSTEM WILL PROVIDE SHOWERS AND POSSIBLE RESTRICTIONS MONDAY NIGHT INTO WEDNESDAY. VFR RETURNS WEDNESDAY NIGHT INTO THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
511 AM EDT SUN SEP 30 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN SEP 30 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER THE ERN GREAT LAKES AND A RIDGE UPSTREAM FROM MN TO NEAR JAMES BAY. SINCE THE LOW HAS EDGED SLIGHTLY TO THE WEST...COOLER AIR AND AN INCREASE IN LOW LEVEL MOISTURE HAS ALSO PUSHED WESTWARD THROUGH UPPER MI WITH SOME PATCHY LOW CLOUDS...ESPECIALLY IN LOCATIONS FAVORED BY NE UPSLOPE FLOW. FARTHER UPSTREAM...A SHRTWV AND NOSE OF A 250-300 JET STREAK WAS MOVING THROUGH SRN ALBERTA. AT THE SFC...A RIDGE EXTENDED FROM NRN QUEBEC TO THE SOUTHWEST INTO THE NRN GREAT LAKES. TODAY...EXPECT ANY LINGERING LOWER CLOUDS TO THIN OUT BY MID TO LATE MORNING WITH INCREASING DAYTIME HEATING. OTHERWISE...HIGH PRES WILL CONTINUE TO DOMINATE THE REGION WITH MOSTLY SUNNY SKIES AND LIGHT ERLY WINDS. WITH LITTLE CHANGE IN THE POSITION OF THE 925-850 MB THERMAL TROUGH...TEMPS SHOULD BE SIMILAR TO SATURDAY WITH MAX READINGS IN THE MID TO UPPER 60S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. TONIGHT...THE SRN CANADA SHRTWV WILL MOVE THROUGH THE NRN PLAINS AND WILL HELP NUDGE THE BLOCKY DOWNSTREAM RIDGE/TROUGH TO THE EAST. HOWEVER...MDLS/ENSEMBLE CONSENSUS SUGGESTS THAT ANY PCPN WITH THE TROUGH SHOULD REMAIN WEST OF LAKE SUPERIOR. AN INCREASE IN SRLY WINDS AND SOME MID AND HIGH CLOUDS SHOULD KEEP TEMPS FROM FALLING OFF AS MUCH. LOOK FOR MIN READINGS FROM THE UPPER 30S TO AROUND 40 INLAND AND CLOSE TO 50 FOR THE GREAT LAKES AND WHERE DOWNSLOPE SSW FLOW PREVAILS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 510 AM EDT SUN SEP 30 2012 AT 12Z MON THERE WILL BE AN UPPER RIDGE OVER THE CWA...WITH A SHORTWAVE TROUGH FROM WRN HUDSON BAY TO WRN MN. AHEAD OF THE SHORTWAVE...A SFC TROUGH WILL BE OVER WRN LAKE SUPERIOR. MODELS NOT SHOWING MUCH MOISTURE WITH THE SYSTEM...OR MUCH QPF...BUT MOST DO SHOW SOME LIGHT PRECIP ASSOCIATED WITH A NARROW BAND OF LOW LEVEL MOISTURE OVER PORTIONS OF THE CWA AS THE SHORTWAVE PASSES MON INTO MON NIGHT. WILL KEEP SLIGHT CHANCE POPS IN THE FORECAST FOR THIS TIME. ATTENTION THEN TURNS TO A MUCH STRONGER SYSTEM THAT MODELS SHOW ENTERING THE NRN PLAINS TUE NIGHT AND STRENGTHENING SOMEWHERE IN THE REGION AROUND THE CWA THU. MODELS THEN SHOW REINFORCING UPPER ENERGY AND COLD AIR MOVING IN FRI INTO THE WEEKEND. OVERALL...THE FORECAST DURING THIS TIME IS VERY UNCERTAIN AND QUITE TRICKY. THERE IS SUBSTANTIAL RUN TO RUN VARIABILITY WITH MOST MODELS AS WELL AS MODEL DISAGREEMENT...SO FORECAST CONFIDENCE IS LOW. THE OVERALL IDEA SHOWN BY MODELS IS THAT THE UPPER TROUGH WILL DEEPEN AND CLOSE OFF SOMEWHERE IN THE REGION THU...AND THEN MOVE NE TO JAMES BAY OR QUEBEC FRI. NW LOW LEVEL WINDS AND 850MB TEMPS AS LOW AS -8C BEHIND THE SYSTEM WOULD BE FAVORABLE FOR LAKE EFFECT RAIN/SNOW FRI INTO SAT. MODELS HAVE BEEN SHOWING A GENERAL NORTHERLY TREND WITH THE LOW TRACK...MORE TOWARD THE ECMWF WHICH HAS SHOWN BETTER CONTINUITY. NOW THE LATEST RUN OF THE GFS (00Z/30) SLOWED THE EVOLUTION OF THE SYSTEM BY 12-18 HOURS FROM THE PREVIOUS RUN. WITH THE SYSTEM CURRENTLY S OF THE ALEUTIAN ISLANDS AT AROUND LAT 45N LON 160W IT IS NOT BEING SAMPLED BY TRADITIONAL UPPER AIR NETWORK...SO HOPEFULLY CONFIDENCE WILL BE IMPROVED WHEN THE SYSTEM MOVES INTO THE OBSERVATION NETWORK OF WRN CANADA AROUND 00Z TUE. IT IS IMPORTANT TO POINT THAT THERE IS A VERY WIDE GAMUT OF POSSIBLE REALITIES RESULTING FROM DIFFERENT PATHS THIS SYSTEM MAY TAKE. IF THE SYSTEM GOES MORE S OF THE CWA...SE TO NE GALES AND A WETTER/SNOWIER FORECAST MAY RESULT. IF THE SYSTEM GOES N OF THE CWA...W GALES AND A DRIER FORECAST MAY RESULT...WITH THE POSSIBILITY OF THUNDERSTORMS ALONG THE ATTENDANT COLD FRONT. IF THE SYSTEM GOES OVER THE CWA...A COMBINATION OF THE PREVIOUS SCENARIOS MAY RESULT. OF COURSE...THERE IS ALSO THE POSSIBILITY THAT THE SYSTEM ENDS UP BEING SIGNIFICANTLY WEAKER (OR EVEN STRONGER) THAN WHAT THE MODELS CURRENTLY SHOW. AM REALLY NOT CERTAIN WHAT WILL HAPPEN...BUT AM LEANING TOWARD THE NRN TRACK OF THE MORE PERSISTENT ECMWF AND FORECAST PERSISTENCE WITH THIS SYSTEM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 133 AM EDT SUN SEP 30 2012 EXPECT MAINLY VFR CONDITIONS THIS FCST PERIOD AT ALL 3 TAF SITES WITH DRY HI PRES OVER ONTARIO DOMINATING. WITH A LIGHT E UPSLOPE WIND...SOME FOG MAY BE POSSIBLE AT SAW. THERE IS ALSO A CHANCE SOME MVFR CIGS MIGHT IMPACT CMX/SAW THRU TODAY...BUT THE AIRMASS APPEARS TOO DRY TO FCST THESE LOWER CONDITIONS ATTM. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN SEP 30 2012 HIGH PRESSURE AND A WEAK PRESSURE GRADIENT WILL PERSIST TODAY. SRLY WINDS WILL INCREASE INTO THE 10 TO 20 KT RANGE TONIGHT AHEAD OF A TROUGH MOVING TOWARD THE REGION. WINDS WILL VEER TO THE WEST MONDAY AND THEN TO THE NORTH MONDAY NIGHT BUT SHOULD REMAIN AT OR BELOW 20 KT. HIGH PRESSURE WILL AGAIN DOMINATE TUESDAY WITH RELATIVELY LIGHT WINDS. A LOW PRESSURE SYSTEM LIFTING INTO NORTHWEST ONTARIO WILL PUSH A COLD FRONT THROUGH LAKE SUPERIOR THURSDAY WITH STRONG WRLY WINDS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...KC/JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
406 AM CDT SUN SEP 30 2012 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MAIN FORECAST CONCERN IS ISOLATED THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON/EVENING... FOLLOWED BY THE PASSAGE OF A COLD FRONT SHORTLY THEREAFTER. WEAK SURFACE HIGH PRESSURE CENTERED NEAR HILL CITY KANSAS THIS MORNING HAS KEPT WINDS LIGHT...WITH ONLY SOME HIGH CLOUDS SCRAPING THE SOUTHEAST 1/3 OF THE FORECAST AREA. TEMPERATURES WARMER IN THE CLOUDY AREAS...AS OPPOSED TO CLOUD FREE REGIONS. ONE EARLY...ALTHOUGH MINOR CONCERN...MAY BE A BIT OF FOG IN THE FAR SOUTHWEST/WESTERN FORECAST AREA. LATEST HRRR DATA IS SHYING AWAY FROM ANY FOG OR LOW CLOUDS IN OUR FORECAST AREA...OPTING INSTEAD JUST TO THE WEST WHERE SOUTHERLY FLOW HAS ALLOWED FOR A LITTLE BETTER MOISTURE RETURN. MOST LIKELY THIS STUFF WOULDN/T GET GOING UNTIL CLOSE TO SUNRISE...SO ITS A GAME TIME DECISION WHETHER ITS WORTH EVEN BEING PART OF THE FORECAST. RIGHT NOW...ITS NOT LOOKING TO LIKELY TO FORM. THE MAIN STORY REST OF THE DAY IS WHETHER THE WESTERN PART OF THE FORECAST CAN SHARE IN SOME ISOLATED SHOWERS/THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. WEAK SURFACE CONVERGENCE ALONG A BOUNDARY STARTS TO PUSHING THE FAR WESTERN SECTION OF THE FORECAST ABOUT MID AFTERNOON. THIS COINCIDES WITH NARROW AXIS OF MOISTURE AND SURFACE INSTABILITY BRIEFLY ABOVE 1000 J/KG. STEEP MID LEVEL LAPSE RATES ALSO SET UP. THERE LIKELY WILL BE SOME HIGH BASED SHOWERS/ISOLATED THUNDERSTORMS FORMING JUST TO THE WEST OF THE FORECAST AREA AROUND 3-4 PM...AND THEN GRADUALLY MIGRATE EAST. HAVE CONTINUED WITH THE 20-30% CHANCE OF RAIN...NOT SO MUCH FOR UNCERTAINTY ON CONVECTIVE ACTIVITY...BUT KEPT THINGS ON THE LOW SIDE WITH LARGE LOW LEVEL DEWPOINT DEPRESSIONS AND CLASSIC INVERTED V SOUNDINGS. BOTH SUGGEST LIMITED RAINFALL...BUT SOME WIND GUST POTENTIAL TO NEAR SEVERE LEVELS. HAVE INCLUDED SOME CHANCE INTO THE EARLY EVENING AS FAR EAST AS HIGHWAY 281...ALTHOUGH THAT MAY WELL BE STRETCHING IT WITH STORM MOTIONS PROBABLY AROUND 10KTS OR SO. LATEST MODELS HAVE FAVORED A LITTLE FURTHER WEST PROFILE...SO KEPT THE BEST SHOT FOR RAIN THERE. WELL...ONCE THAT STUFF WRAPS BY LATE EVENING...ATTENTION TURNS TO ONCOMING COLD FRONT LATE TONIGHT AND EARLY MONDAY. PRETTY STRONG PRESSURE RISES AS THE FRONT PASSES...SO EXPECT THE WIND TO PICK UP PRETTY STEADY BY LATE TONIGHT. GOOD MOMENTUM TRANSFER WILL CONTINUE ALL DAY MONDAY WITH NEARLY UNIDIRECTIONAL FLOW GIVING US THE FIRST BREEZY/WINDY DAY...SINCE THE LAST COLD FRONT A FEW DAYS AGO. MODELS TRY TO SQUEEZE OUT SOME LIGHT SHOWERS...PROBABLY SPRINKLES. NONE THE LESS...HAVE WORKED IN TANDEM WITH OTHER OFFICES TO INCLUDE A SLIGHT CHANCE OF LIGHT SHOWERS MONDAY MORNING...BEFORE SUNSHINE TAKES OVER LATER. TEMPERATURES WILL NOT ONLY FEEL COOLER DUE TO THE NORTH WIND...BUT ACTUALLY BE COOLER DURING THE DAY MONDAY. NOT MUCH ELSE TO WORRY ABOUT MONDAY NIGHT THROUGH TUESDAY NIGHT... WITH A COOL NIGHT MONDAY NIGHT...GIVING WAY TO A REALLY NICE AND MILD DAY TUESDAY WITH SUNSHINE AND LIGHT WINDS. .LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. A COLD FRONT PROGGED TO TRANSITION THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY WILL PROVE TO BE THE MOST CHALLENGING ASPECT OF THE EXTENDED FORECAST. CHALLENGES WILL RESULT IN PRECIPITATION TIMING/COVERAGE AND TEMPERATURES BOTH AHEAD AND BEHIND THE COLD FRONT. PRECIP CHANCES WILL ALSO BE REALIZED TOWARDS THE END OF THE LONG TERM. A COLD FRONT WILL EXTEND DOWN INTO THE CENTRAL PLAINS ON THURSDAY FROM FROM AN ASSOCIATED UPPER LEVEL TROUGH FORECAST TO PASS THROUGH THE NORTHERN PLAINS. RETURN FLOW IN THE LOWER LEVELS AHEAD OF THIS FRONTAL BOUNDARY SHOULD ADVECT ENOUGH MOISTURE INTO THE CENTRAL PLAINS TO HELP AID IN THE DEVELOPMENT OF SOME STRATIFORM RAIN ACROSS THE OUTLOOK AREA. FORECAST SOUNDINGS SUGGEST A MOIST ATMOSPHERIC PROFILE BEGINNING AROUND MIDNIGHT ON WEDNESDAY AND CONTINUING THROUGH THE MORNING HOURS OF THURSDAY. PRECIPITATION TIMING WILL RELY SOLELY ON THE TIMING OF THE COLD FRONT...BUT CURRENT ANALYSIS LEADS TO PRECIP BEGINNING LATE WEDNESDAY NIGHT AND CONTINUING THROUGH THURSDAY MORNING BEHIND THE COLD FRONT. NO SEVERE WEATHER IS ANTICIPATED. THE BIGGEST CHANGE IN THE FORECAST WAS WEDNESDAY HIGH TEMPERATURES...WHICH WILL BE NEAR 80 DEGREES AHEAD OF THE FRONT FOR MOST OF THE OUTLOOK AREA. THIS CHANGE IS MAINLY DUE TO THE TIMING OF THE FRONT BEING A LITTLE SLOWER THAN PREVIOUSLY FORECAST. FURTHERMORE...850MB TEMPS ALSO SUGGEST HIGHER TEMPERATURES THAN THE OUTPUT FROM ALLBLEND. THURSDAY HIGH TEMPERATURES AND FRIDAY MORNING LOW TEMPERATURES HAVE BEEN RATHER TRICKY WITH THE PASSAGE OF THE FRONTAL BOUNDARY OVER THE LAST COUPLE OF DAYS. SEEMS AS THOUGH THE MODELS MAY HAVE FINALLY SETTLED ON A SOLUTION. THE PAST SEVERAL DAYS HAVE SHOWN A GENERAL DECREASE IN TEMPERATURES ACROSS THE CWA FOR THURSDAY HIGH TEMPERATURES AND THE OVERNIGHT LOWS...BUT TEMPERATURES ARE NOW NEARLY CONSISTENT WITH THE PREVIOUS FORECAST. THURSDAY WILL BE BELOW NORMAL FOR HIGHS AS UPPER 50S AND LOWER 60S ARE FORECAST. IN FACT...THE REST OF THE LONG TERM IS FORECAST TO EXPERIENCE BELOW NORMAL TEMPERATURES FOR THIS TIME OF YEAR. THURSDAY NIGHT LOW TEMPERATURES ARE STILL FLIRTING WITH FROST POTENTIAL. WILL NEED TO MONITOR THIS OVER THE NEXT COUPLE OF DAYS. A FROST ADVISORY MIGHT HAVE SOME CREDIBILITY ACROSS NORTHERN PARTS OF THE CWA NEXT WEEK. THERE WILL BE A CHANCE FOR PRECIPITATION FRIDAY NIGHT AND INTO SATURDAY AS ANOTHER CONVERGENCE ZONE SETS UP OVER THE CENTRAL PLAINS WITH FORECAST SOUNDINGS SUGGESTING A MOIST ATMOSPHERIC PROFILE. AGAIN...SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME. && .PREV DISCUSSION... /ISSUED 1209 AM CDT SUN SEP 30 2012/ AVIATION...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE VALID TAF PERIOD. FORECAST SOUNDINGS SUGGEST HIGH CLOUDS WILL EXIT THE TERMINAL SITE AROUND SUNRISE...AND A PERIOD OF CLEARER SKIES WILL BEGIN IN THE WAKE OF AN ARRIVING COLD FRONT ON MONDAY. WIND SPEEDS WILL BE LIGHT TODAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM....NOAA/NWS/MORITZ LONG TERM/AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
358 AM EDT SUN SEP 30 2012 .SYNOPSIS... LOW PRESSURE OVER THE EAST COAST WILL MOVE SLOWLY NORTHEAST AND EXTEND A TROUGH BACK WEST OVER THE REGION THROUGH TONIGHT. HIGH PRESSURE WILL BUILD EAST ON MONDAY ACROSS THE AREA. LOW PRESSURE AND RESULTING WARM FRONT WILL LIFT NORTH ACROSS THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE UPPER LOW OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WILL MOVE SOUTHEAST TODAY. THE BIG QUESTION IS WHAT KIND OF POP IS NEEDED FOR NE OH AND NW PA AND HOW FAR WEST TO CARRY A THREAT. THE HRRR MODEL REALLY DECREASES THE THREAT BY DAYBREAK. WITH THE INSTABILITY SO STRONG THE LAKE AND 500 MB TEMPERATURE DIFFERENCE NEAR 43C FROM LAKE COUNTY EAST TODAY...WILL KEEP THE LIKELY POPS GOING THROUGH EARLY TO MID AFTERNOON AND THEN DECREASE THEM AS SUBSIDENCE OCCURS BEHIND THE VORT MAX. THE HRRR IS NOW KEEPING SHOWERS GOING LONGER INTO THE AFTERNOON WHICH SEEMS GOOD WITH SOME MUCH INSTABILITY. MOST MODELS AGREE WITH THIS. CONFIDENCE IS MODERATE. AS PER THE HRRR MODEL AND SOME SHOWERS ON LAKE HURON WILL HAVE A THREAT OF SHOWERS AS FAR WEST AS THE ISLANDS. USED A BLEND OF GUIDANCE FOR THE HIGHS...COOLER EAST BECAUSE OF THE CLOUDS AND SHOWERS AND WARMER WEST WITH SOME SUNSHINE THIS AFTERNOON. WILL MENTION OF THREAT OF SMALL HAIL IN EXTREME NE OH AND NW PA AND WATERSPOUTS OVER THE EAST END OF THE LAKE. THIS WILL BE IN GRIDS AND THE HWO. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE WILL BE BUILDING IN BUT WITH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE NEAR 13C SOME LAKE ENHANCED SHOWERS MAY OCCUR. THE BEST CHANCE WOULD BE NW PA WHERE THE MOISTURE IS A LITTLE BETTER...ESPECIALLY EARLY TONIGHT. ELSEWHERE SOME CIRRUS WILL BE MOVING IN FROM THE SOUTHWEST. THIS MAY HELP LIMIT ANY WIDESPREAD DENSE FOG FROM DEVELOPING...SO WILL NOT MENTION IT AT THIS TIME. WATCHING THE NEXT WEATHER MAKER FOR THE REGION FROM THE GULF OF MEXICO. THE 00Z ECMWF IS VERY QUICK WITH THIS SYSTEM...DIDN`T GO AS FAST AS THE ECMWF BUT DID SPEED THE TIMING OF THE SHOWERS A LITTLE BIT. LIKELY LOOKS GOOD MONDAY NIGHT INTO TUESDAY AND THEN CHANCE AFTER THAT AS WE GET CLOSE TO THE WARM SECTOR. AT THIS TIME NO MENTION OF THUNDER BUT A THREAT WILL EVENTUALLY HAVE TO BE MENTIONED. NOT CONFIDENT ENOUGH TO FORECAST IT AT THIS TIME. USED A BLEND OF THE GUIDANCE BUT WITH PLENTY OF CLOUDS AND SHOWERS AROUND WENT COOLER FOR THE HIGHS AND WARMER FOR THE LOWS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE PERIOD WILL START OUT DRY ON THURSDAY AS THE AREA WILL BE BETWEEN WEATHER SYSTEMS. MODELS CONTINUE TO MOVE NEXT COLD FRONT ACROSS THE AREA ON FRIDAY. ECMWF CONTINUES TO BE THE FASTER OF THE 2 MODELS. ECMWF HAS THE FRONT JUST EXITING THE AREA BY 12Z FRIDAY WHILE THE GFS JUST HAS THE FRONT INTO NW OH. CONTINUED TO USE THE SLOWER GFS FOR FORECAST. MODELS DIFFER SIGNIFICANTLY ON SATURDAY. ECMWF HAS ANOTHER STRONG COLD FRONT PUSHING ACROSS THE AREA ON SATURDAY. GFS ON OTHER HAND HAS LARGE LOW SETTING UP OVER JAMES BAY WITH A SERIES OF TROUGHS SWINGING ACROSS EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE GFS SOLUTION. LEFT CHANCE POPS SNOWBELT EAST OF CLEVELAND FOR SATURDAY WITH TROUGH AND IN ADDITION 850 MB TEMPS DIP TO MINUS 4C SETTING UP POTENTIAL FOR LAKE EFFECT SHOWERS. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... SURFACE TROUGH SWINGING ACROSS EASTERN PORTION OF FORECAST AREA NOW KICKING OFF A FEW SHOWERS. WILL BE A BRIEF RESPITE...THEN UPPER LEVEL VORTICITY MAX NOW OVER LAKE HURON WILL SWING ACROSS THE AREA SHORTLY AFTER SUNRISE. THIS WILL ALSO KICK OFF A FEW SHOWERS...BUT DO NOT THINK IT WILL BE ANY WORSE THAN MVFR CONDITIONS IN THE HEAVIER SHOWERS. AGAIN MOST SHOWERS WILL BE FROM CLEVELAND EAST. SKIES WILL BEGIN TO SCATTER OUT FROM THE NORTH BY MID AFTERNOON AS THE VORT MAX SWINGS SOUTH OF THE AREA. .OUTLOOK...NON-VFR CONDITIONS PROBABLE TUESDAY INTO WEDNESDAY IN SHRA. && .MARINE... FLOW WILL BECOME NORTHEAST TODAY BUT CONDITIONS WILL STAY BELOW SMALL CRAFT ADVISORY CRITERIA. NE FLOW WILL CONTINUE ON SUNDAY AND THEN BECOME NORTHERLY ON SUNDAY NIGHT AS HIGH PRESSURE BRIEFLY RETURNS. LOCAL SCHEMES SHOWING A GOOD CHANCE FOR WATERSPOUTS ON SUNDAY. BEST CHANCES FOR THIS WILL BE TO THE EAST OF CLEVELAND AND ANYWHERE A DECENT SHOWER DEVELOPS. LOW PRESSURE STILL FORECAST TO MOVE ACROSS THE OHIO VALLEY ON TUESDAY...AND ACROSS LAKE ERIE TUESDAY NIGHT. MODELS STILL NOT IN GOOD AGREEMENT ON EXACT TRACK AND TIMING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1043 AM EDT SUN SEP 30 2012 .SYNOPSIS... A BROAD UPPER LEVEL STORM SYSTEM IMPACTS THE NORTHEAST INTO MONDAY. WEAK HIGH PRESSURE BUILDS IN MONDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM...WHICH WILL PASS THROUGH MID WEEK. HIGH PRESSURE BRIEFLY BUILDS IN THE END OF THE WEEK BEFORE THE NEXT FRONT APPROACHES FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST WATER VAPOR AND RUC ANALYSIS SHOW CUTOFF LOW ALOFT CENTERED NEAR THE WESTERN NY/PA BORDER...WITH A 33 UNIT 500 HPA VORTICITY MAXIMUM JUST S OF LONG ISLAND LIFTING NE. AHEAD OF THIS VORTICITY MAXIMUM - STRONG POSITIVE VORTICITY ADVECTION - THERE ARE ISOLD- SCT SHRA...AND BEHIND IT - NEGATIVE VORTICITY ADVECTION - DRY CONDITIONS WITH AT MOST FEW-SCT CLOUD COVERAGE. THE NEXT VORTICITY MAXIMUM APPROACHES WESTERN ZONES BY LATE AFTERNOON...SO INTRODUCE ISOLD-SCT SHRA THERE. SHOWALTER INDICES AROUND TO JUST BELOW 0 ARE FORECAST ACROSS THE NORTHERN AND FAR EASTERN PORTIONS OF THE CWA THIS AFTERNOON...SO HAVE ISOLATED THUNDER IN FOR THOSE LOCATIONS. A BLEND OF NAM/SREF/HRRR POPS REFLECTS PRECIPITATION TREND FAIRLY WELL...THOUGH MIGHT BE UNDER DOING AREA TO BE MAINLY DRY LATE THIS MORNING INTO THIS AFTERNOON. CMC-REG SKY PRODUCT CAPTURES CURRENT AREA OF MAINLY SKC FROM NJ BACK INTO EASTERN PA...SO HAVE USED IT TO UPDATE SKY GRIDS...RESULTING IN A SIGNIFICANT DECREASE IN CLOUD COVER FORECAST...ESPECIALLY FOR SOUTHERN ZONES. 12Z KOKX AND KALY SOUNDINGS SUGGEST HIGHS RANGING FROM THE LOWER 60S ACROSS THE NORTHERN INTERIOR TO THE MID-UPPER 60S NEAR THE COAST. THIS IS CONSISTENT WITH A BLEND OF 6Z MAV/NAM 2-METER TEMPERATURES WITH 00Z MET GUIDANCE. HOURLY AND HIGH TEMPERATURE GRIDS ADJUSTED ACCORDINGLY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... DRYING CONDITIONS THIS PERIOD AS THE UPPER LEVEL LOW FINALLY PUSHES OFF TO THE NORTHEAST...ALLOWING FOR RIDGING TO BUILD IN ON MONDAY. THE SURFACE LOW MOVES OFF TO THE NORTH AS WELL...DRAGGING A TROUGH THROUGH THE CWA...RESULTING IN A MORE WESTERLY FLOW TO THE WEST...AND A SOUTHWESTERLY FLOW OVER THE EAST. A TIGHTENING PRESSURE GRADIENT BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FROM THE SOUTH WILL INCREASE WINDS LATE SUNDAY NIGHT INTO MONDAY...WITH GUSTS BETWEEN 15 AND 20 MPH POSSIBLE. SOUNDINGS INDICATE DRYING AT ALL LEVELS AS THE LOW MOVES AWAY AND COOLER AIR IS USHERED IN ON THE BACKSIDE OF THE LOW...CREATING PLENTY OF SUBSIDENCE FOR MONDAY. OTHER THAN A FEW LINGERING SHOWERS THIS EVENING...SHOULD HAVE A DRY FORECAST UNTIL MONDAY NIGHT WHEN THE FLOW RETURNS TO THE SOUTH AND THE MOISTURE FIELD BEGINS INCREASING. GFS THE WARMEST WITH TEMPS WITH IT PUSHING THE LOW OUT THE QUICKEST. SIDED WITH THE SLIGHTLY SLOWER NAM GUIDANCE FOR TEMPS...WHICH KEEPS TEMPS NEAR NORMAL. IF SKIES CLEAR QUICKER THAN FORECASTED...COULD SEE TEMPS DROP ANOTHER COUPLE OF DEGREES...ESP INLAND. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... OVERALL...UNSETTLED WEATHER STILL FORECASTED FOR MID WEEK...WITH A BREAK IN THE PRECIPITATION POSSIBLE THURS/FRI. WHILE MODEL DISCREPANCIES ARE STILL IN PLACE...THERE IS SOME BETTER ALIGNMENT WITH THE 00Z RUNS...ALLOWING FOR SLIGHTLY HIGHER CONFIDENCE ON THE FORECAST. WEAK HIGH PRESSURE AT THE SURFACE BEGINS TO RETREAT TUESDAY AS A WARM FRONT ASSOCIATED WITH A SURFACE LOW OVER THE OHIO RIVER VALLEY APPROACHES AND MOVES THROUGH THE NORTHEAST. DESPITE DIFFERENCES IN THE EXACT TIMING...GENERAL MODEL CONSENSUS IS A TAD SLOWER WITH THE PROGRESSION OF THE LOW AND ITS ASSOCIATED FRONTS. 00Z NAM REMAINS THE MAIN OUTLIER WITH TIMING...REALLY SLOWING EVERYTHING DOWN TILL WED. HOWEVER...DECIDED TO SIDE WITH THE MORE CONSISTENT AND PROGRESSIVE PATHS...BRINGING THE PRECIPITATION IN BY TUES NIGHT. KEPT CHANCE POPS IN FOR TUES MORNING WITH INCREASING WAA/MOISTURE FIELD...THEN INCREASED POPS THROUGHOUT THE DAY INTO TUES NIGHT ALONG THE ISENTROPIC LIFT. ALSO TIMED PRECIPITATION OUT TO CORRESPOND WITH PASSING SHORTWAVES ALONG THE NORTHERN FRINGE OF THE UPPER LEVEL RIDGE. CHANCE OF PRECIPITATION REMAINS MENTIONED THROUGH WED ALONG THE PASSAGE OF THE COLD FRONT/SURFACE LOW. HOWEVER...WITH RIDGING IN PLACE ALOFT...EXPECT THINGS TO DRY OUT RATHER QUICKLY ONCE THE FRONT PASSES. SURFACE HIGH PRESSURE BUILDS IN FROM THE SOUTH THURS INTO FRI...WHICH SHOULD KEEP THE DRY WEATHER IN PLACE. ANOTHER STORM SYSTEM IS EXPECTED TO IMPACT THE AREA THIS WEEKEND...BUT TIMING IS STILL UNCERTAIN AT THIS TIME. THUS...CONTINUED PREVIOUS FORECAST FOR THE END OF THE WEEK DUE TO THESE UNCERTAINTIES. WAA AHEAD OF THE COLD FRONT MID WEEK WILL PUSH TEMPS BACK TO ABOVE NORMAL TUES THROUGH THURS...WITH CLOUDY CONDITIONS AND RAIN MODERATING TEMPS. SLIGHT COOLING SETTLES IN FRI...BUT THE NEXT BURST OF COOLER AIR LOOKS TO BE AFTER THE FRONT THIS WEEKEND. GENERALLY WENT WITH A BLEND OF HPC/MOS GUIDANCE FOR TEMPS AND DEW POINTS. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... LOW PRES E OF CAPE COD WILL CONTINUE TO TRACK N TODAY. LIGHT N/NW FLOW WILL BACK TO THE WNW THIS AFTN. SPEEDS WILL INCREASE INTO THE 10-15KT RANGE AFT 18Z. VFR IS OVERSPREADING THE REGION FROM THE SW. THIS TREND IS EXPECTED TO CONTINUE. CU IS EXPECTED TO BEGIN TO DEVELOP IN THE 16-18Z PERIOD. ISOLD-SCT SHRA ARE POSSIBLE...HOWEVER THE BULK OF THIS ACTIVITY IS PROGGED TO BE N OF THE CITY TERMINALS. ANY SHRA DISSIPATE BY 23-00Z. TONIGHT...WINDS REMAIN FROM THE WEST AROUND 10 KT OR LESS WITH VFR CONDITIONS. OUTLOOK FOR 12Z MONDAY-THURSDAY... .MONDAY-MONDAY NIGHT...VFR. GUSTS ARE POSSIBLE DURING THE DAY MONDAY. .TUESDAY-WEDNESDAY...MVFR OR LOWER CONDITIONS POSSIBLE IN SHRA. .WEDNESDAY NIGHT-THURSDAY...VFR. && .MARINE... MINOR CHANGES MADE IN THE GRIDS TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. SUB-SCA CONDITIONS TODAY WITH A NORTHERLY TO WESTERLY FLOW BETWEEN 5 AND 10 KTS. AS THE LOW DEPARTS TOMORROW AND THE HIGH BUILDS IN...TIGHTENING PRESSURE GRADIENT WILL INCREASE BOTH WINDS AND SEAS...WITH POSSIBLE GUSTS UP TO 25 KTS. THE PERSISTENT FLOW COULD INCREASE SEAS TO 5 FT ON THE OCEAN WATERS. WINDS AND SEAS DIMINISH BY TUESDAY AND SHOULD REMAIN SUB SCA FOR THE REMAINDER OF THE FORECAST. OCCASIONAL HIGHER GUSTS POSSIBLE WITH THE PASSAGE OF THE FRONT ON WED. && .HYDROLOGY... SIGNIFICANT PRECIPITATION IS NOT EXPECTED THROUGH SUNDAY NIGHT. A PROLONGED PERIOD OF STRATIFORM RAIN IS POSSIBLE FROM LATE MONDAY NIGHT INTO WEDNESDAY. SINCE THIS WILL BE A LONG DURATION EVENT AND HEAVY RAIN IS NOT EXPECTED AT THIS TIME...FLOODING DOES NOT APPEAR TO BE A CONCERN. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...SEARS NEAR TERM...MALOIT SHORT TERM...SEARS LONG TERM...SEARS AVIATION...BC/JMC MARINE...MALOIT/SEARS HYDROLOGY...
AREA FORECAST DISCUSSION
NWS MIAMI FL
1022 AM EDT SUN SEP 30 2012 .UPDATE...BASED ON CURRENT TRENDS AND OBSERVATIONS, DO NOT PLAN TO MAKE ANY CHANGES WITH THE MORNING UPDATES. THE 12Z MFL SOUNDING WAS CONTAMINATED IN THE LOWEST LEVELS SO THE PWAT VALUE WAS CALCULATED WAY TOO LOW. HOWEVER, IT DOES SHOW A GENERAL INCREASE IN MOISTURE THROUGH THE MID LEVELS AND BASED ON THIS IT APPEARS THE PWAT HAS PROBABLY INCREASED BACK CLOSE TO TWO INCHES. IT DEPICTS ONLY A MARGINALLY UNSTABLE AIRMASS SO THE 30-40 PERCENT POPS LOOK REASONABLE. THE HRRR DOES INDICATE NNW STORM MOTION WITH SCATTERED COVERAGE AND THIS ALSO SEEMS REASONABLE GIVEN ABOVE DISCUSSION. KOB && .PREV DISCUSSION... /ISSUED 727 AM EDT SUN SEP 30 2012/ AVIATION...ISOLATED SHRA MOVING NW THROUGH THE ATLC WATERS AND GULF WATERS AT THIS TIME WITH THE ACTIVITY OCCASIONALLY MOVING UPON THE E COAST. HAVE VCSH INITIALLY IN E COAST TAFS AND VERY BRIEF MVFR CIG POSSIBLE. CURRENT E COAST SURFACE WINDS CALM TO LIGHT SE WITH SEA BREEZE INCREASING SE 10 TO 12 KNOTS AFT 16Z. TSRA TO DEVELOP MAINLY ALONG THE SEA BREEZE WITH VCTS IN TAFS AFT 17/18Z. TSRA MAY BE FAR ENOUGH INLAND TO AFFECT ONLY KTMB AND KPBI. AT KAPF ...SHRA SHOULD REMAIN OFFSHORE WITH VCTS IN TAFS AFT 18Z THROUGH 30/00Z. AT KAPF CURRENT SURFACE WIND CALM BECOMING ESE-SE < 10 KNOTS AFT 13Z THEN SSW-SW TO 10 KNOTS AFT 16Z AS W COAST SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 307 AM EDT SUN SEP 30 2012/ .POTENTIAL FOR HEAVY RAIN AND LOCALIZED FLOODING ACROSS SOUTH FLORIDA MONDAY AND TUESDAY... DISCUSSION... WATER VAPOR ANALYSIS FROM THIS MORNING SHOWED A LARGE UPPER LOW SPINNING OVER THE LOWER GREAT LAKES...AND ANOTHER CUT OFF LOW OVER OKLAHOMA. UPPER LEVEL HIGH PRESSURE WAS LOCATED ACROSS THE PACIFIC AND WEST COAST AND OUT ACROSS THE WESTERN ATLANTIC. AT THE SURFACE...LOW PRESSURE WAS LOCATED ACROSS EAST TEXAS AND A WEAK FRONT WAS ACROSS THE SOUTHEAST AND INTO THE WESTERN ATLANTIC. A WEAK RIDGE AXIS WAS LOCATED FROM THE WESTERN ATLANTIC ACROSS THE LAKE OKEECHOBEE REGION. FOR SOUTH FLORIDA...LOW LEVEL SOUTHEAST FLOW HAS BEGUN...BUT DEEP MOISTURE WAS STILL LOCATED OVER THE CARIBBEAN. SOME DRIER AIR WAS ALSO NOTED OVER THE YUCATAN NORTHEASTWARD TO OFF WEST COAST OF SOUTH FLORIDA. A SHORTWAVE IS EXPECTED TO DIVE SOUTHEAST ACROSS THE PACIFIC NORTHWEST...AND THE CUT OFF LOW IS EXPECTED TO DEEPEN ACROSS THE ARKLATEX REGION. THIS WILL AMPLIFY THE UPPER PATTERN THROUGH THE MIDDLE OF THE WEEK...WITH A DEEP TROUGH ACROSS THE SOUTH AND STRONG RIDGES ACROSS THE WEST COAST AND OVER THE WESTERN ATLANTIC. DEEP SOUTH TO SOUTHWEST FLOW WILL DEVELOP OVER SOUTH FLORIDA...PULLING TROPICAL MOISTURE OUT OF THE CARIBBEAN OVER THE REGION LATE TONIGHT THROUGH TUESDAY. SINCE MODELS HAVE SLOWED DOWN THE TIMING OF THE DEEP TROPICAL MOISTURE UNTIL TONIGHT...AND WITH WARM AND DRY AIR ALOFT...500MB TEMPS AROUND -4C TO -5C...CUT BACK POPS SLIGHTLY FOR TODAY. WENT WITH A BLEND OF MAV AND ECMWF FOR THE POPS...WITH STILL A CHANCE OF STORMS ACROSS THE REGION. EXPECT MAINLY SEA BREEZE ACTIVITY...WITH OVERALL STORM MOTION SLOW TO THE NORTH. THE UPPER LOW OVER THE NORTHEAST CONUS WILL SLOWLY SLIDE TO THE NORTHEAST...AND SURFACE LOW PRESSURE WILL MOVE ACROSS THE NORTHERN GULF AND INTO THE SOUTHEAST STATES EARLY NEXT WEEK. A COLD FRONT ATTACHED TO THE SURFACE LOW WILL MOVE INTO THE CENTRAL/EASTERN GULF ON MONDAY AND THEN INTO CENTRAL FLORIDA AND NEAR LAKE OKEECHOBEE ON TUESDAY. SO FOR MONDAY...PWATS WILL INCREASE TO AROUND 2.1-2.4 INCHES...AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. ALTHOUGH STORM MOTION IS NOT TERRIBLY SLOW...AROUND 10 KNOTS TO THE NORTHEAST...WITH THE DEEP MOISTURE AND SATURATED SOILS ACROSS SOUTH FLORIDA THERE WILL A POTENTIAL FOR LOCALLY HEAVY RAINFALL. HPC PAINTS AROUND 1 INCH OF RAIN AREAL AVERAGE ACROSS THE ENTIRE EASTERN TWO-THIRDS OF SOUTH FLORIDA...SO LOCALIZED SPOTS COULD SEE 2 TO 4 INCHES OF RAIN AND POSSIBLY MORE. SO LOCALIZED FLOODING IS THE BIGGEST CONCERN. FLASH FLOOD GUIDANCE IS NOT STILL RELATIVELY HIGH...3-4 INCHES FOR 1 HOUR...AROUND 4 INCHES FOR 3 HOURS...AND 4-5.5 INCHES FOR 6 HOURS. WITH NO REAL FOCUS FOR STORMS AND CLOUD COVER POSSIBLY HAMPERING OVERALL ACTIVITY...WILL NOT ISSUE A FLOOD WATCH AT THIS TIME. WENT BELOW GUIDANCE BY A FEW DEGREES FOR HIGH TEMPERATURES DUE TO EXPECTED CLOUD COVER AND RAINFALL ON MONDAY. SOME OF THE DRIER AIR PREVIOUSLY MENTIONED ACROSS THE EASTERN GULF AND TOWARDS THE YUCATAN MAY TRY TO PUSH INTO THE GULF COAST OF SOUTH FLORIDA MONDAY NIGHT DUE TO THE SOUTHWEST FLOW ALOFT. HOWEVER...HIGH PRESSURE ACROSS THE WESTERN ATLANTIC WILL BEGIN TO STRENGTHEN AND BATTLE BACK AGAINST THE TROUGH OVER THE SOUTH...AND THE DEEP MOISTURE IS FORECAST TO PUSH BACK ACROSS AT LEAST THE EASTERN TWO-THIRDS OF THE REGION ON TUESDAY. HEIGHTS WILL BEGIN TO RISE ACROSS THE REGION...BUT THERE WILL BE ANOTHER CHANCE FOR LOCALLY HEAVY RAINFALL...MAINLY FOR THE EAST COAST METRO AREAS. HIGH PRESSURE WILL CONTINUE TO STRENGTHEN ACROSS THE WESTERN ATLANTIC TUESDAY NIGHT INTO WEDNESDAY WITH HEIGHTS OF 596-598 DECAMETERS...AND 592-593 DECAMETERS ACROSS SOUTH FLORIDA. THE FLOW WILL BECOME MORE SOUTHEASTERLY AS HIGH PRESSURE BUILDS IN...AND THE DEEP MOISTURE WILL BEGIN TO GET PUSHED TO THE NORTHWEST. PWATS WILL FALL TO 1.8 TO 2 INCHES ACROSS THE REGION...HIGHEST ACROSS THE NORTHWEST. THE PERSISTENT TROUGH OVER THE DEEP SOUTH WILL BEGIN TO LIFT TO THE NORTHEAST AS ANOTHER TROUGH DIGS INTO THE NORTHERN PLAINS ON THURSDAY...AND HIGH PRESSURE WILL BEGIN TO WEAKEN OVER THE WESTERN ATLANTIC. SURFACE HIGH PRESSURE WILL DEVELOP OVER THE SOUTHEAST AND EASTERLY FLOW WILL DEVELOP ACROSS THE REGION...WITH MORE TYPICAL SEA BREEZE TYPE CONVECTION. HOWEVER...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL FLORIDA OR NEAR LAKE OKEECHOBEE...KEEPING RELATIVELY HIGH LEVELS OF MOISTURE...PWATS NEAR 2 INCHES...INTO THE WEEKEND. SO RAIN CHANCES WILL REMAIN AT OR ABOVE NORMAL THROUGH NEXT SATURDAY. TEMPERATURES ARE EXPECTED TO REMAIN NEAR NORMAL THROUGH THE PERIOD. AVIATION...FOR 06Z TAFS. WIDELY SCATTERED SHRA MOVING NW THROUGH THE ATLC WATERS AND GULF WATERS WITH THE ACTIVITY OCCASIONALLY MOVING UPON THE E COAST. VERY BRIEF MVFR CIG POSSIBLE. VCSH IN E COAST TAFS. E COAST SEA BREEZE INCREASES SE WINDS AFT 16Z AND TSRA TO DEVELOP MAINLY ALONG THE SEA BREEZE WITH VCTS IN TAFS. POTENTIAL THAT TSRA MAY BE FAR ENOUGH INLAND TO AFFECT MAINLY KTMB AND KPBI. AT KAPF...SHRA SHOULD REMAIN OFFSHORE WITH VCTS AFT 18Z THROUGH 30/00Z. E COAST SURFACE WINDS CURRENTLY CALM TO SE-SSE < 5 KNOTS UNLESS BECOMING VARIABLE FOR A SHORT PERIOD OF TIME IF A SHRA MOVES OVER THE AREA...BECOMING SE 10-12 KNOTS AFT 15Z. AT KAPF CURRENT SURFACE WIND CALM TO SE < 5 KNOTS INCREASING AFT 12Z 5 TO 8 KNOTS THEN SHIFTING SSW-SW TO 10 KNOTS AFT 16Z AS W COAST SEA BREEZE DEVELOPS. MARINE... WIND AND SEAS WILL REMAIN QUITE TRANQUIL THROUGH THE WEEKEND WITH LIGHT SOUTHEAST FLOW BECOMING MORE SOUTHERLY ON SUNDAY. A STRONGER SOUTH WIND WILL BEGIN TO DEVELOP MONDAY AND TUESDAY IN RESPONSE TO THE DEVELOPING LOW PRESSURE WITH SEAS POSSIBLY BUILDING TO AROUND 4 FEET. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH HIGH LOW LEVEL MOISTURE IN PLACE THIS WEEKEND AND ALL OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 77 87 77 / 30 30 70 50 FORT LAUDERDALE 89 76 86 77 / 30 40 70 50 MIAMI 88 78 86 77 / 30 40 70 50 NAPLES 89 77 89 77 / 20 20 60 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
904 AM CDT SUN SEP 30 2012 .DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * LAKE EFFECT CIGS BECMG MVFR INTO EARLY AFTERNOON...INITIALLY MAY BE BRIEFLY BELOW 2 KFT...BUT SHOULD QUICKLY LIFT TO 2-2.5 KFT. * NORTHEAST WINDS BECOMG GUSTY TO G15KT BY LATE MORNING. * SMALL CHANCE FOR MVFR CIGS TONIGHT AND EARLY MONDAY MORNING. KREIN //DISCUSSION...UPDATED 12Z... THE TERMINALS LIE BETWEEEN A COLD FRONT TO THE SOUTH WHICH PASSED LATE YESTERDAY AND HIGH PRESSURE ACROSS ONTARIO AND QUEBEC. THE GRADIENT BETWEEN THESE FEATURES WILL CONTINUE TO FAVOR A NORTHEAST SYNOPTIC WIND. INITIALLY...THROUGH 14Z...A SLIGHTLY MORE NNW WIND WILL BE SEEN ACROSS NORTHEAST IL DUE TO A REMNANT LAND BREEZE FROM THE NIGHT. THIS IS AIDING CONVERGENCE INTO NORTHEAST IL THAT SHOULD HELP TO FOCUS DEVELOPING CLOUDS OVER THE LAKE INTO NORTHEAST IL BY MID MORNING...AND LIKELY TOWARD GYY AS WELL. THESE LAKE ENHANCED CLOUDS ARE PRESENTLY FAVORED TO BE AT OR ABOVE 2000 FT BY THE TIME THEY ARRIVE AT THE TERMINALS...BUT AT ONSET SOME COULD BE BELOW 2000 FT. THAT SHOULD BE BRIEF IF THAT OCCURS. CLOUDS SHOULD GRADUALLY BECOME MORE SCATTERED THROUGH THE AFTERNOON AS THE COLD AIR ADVECTION COMPONENT OVER THE WATER WEAKENS. THE HIGH PRESSURE WILL SETTLE SOUTHWARD OVER THE AREA THIS EVENING...WITH RETURN FLOW DEVELOPING ON MONDAY. //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN BROKEN CLOUDS BETWEEN 2000 AND 3500 FT. MEDIUM CONFIDENCE IN TIMING. LOW CONFIDENCE IN ANY CIGS BELOW 2000 FT. * HIGH CONFIDENCE IN WIND DIRECTIONAL TRENDS. MEDIUM CONFIDENCE IN GUSTS. * LOW CONFIDENCE IN ANY RETURNING BROKEN CIGS TONIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
647 AM CDT SUN SEP 30 2012 .DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LAKE EFFECT MVFR CIGS PROBABLE DURING THE MID-MORNING INTO EARLY AFTERNOON...SOME OF WHICH AT ONSET COULD BE BELOW 2000 FT. * NORTHEAST WINDS INCREASING IN SPEED BY MID-MORNING. * SMALL CHANCE FOR MVFR CIGS TONIGHT AND EARLY MONDAY MORNING. //DISCUSSION...UPDATED 12Z... THE TERMINALS LIE BETWEEEN A COLD FRONT TO THE SOUTH WHICH PASSED LATE YESTERDAY AND HIGH PRESSURE ACROSS ONTARIO AND QUEBEC. THE GRADIENT BETWEEN THESE FEATURES WILL CONTINUE TO FAVOR A NORTHEAST SYNOPTIC WIND. INITIALLY...THROUGH 14Z...A SLIGHTLY MORE NNW WIND WILL BE SEEN ACROSS NORTHEAST IL DUE TO A REMNANT LAND BREEZE FROM THE NIGHT. THIS IS AIDING CONVERGENCE INTO NORTHEAST IL THAT SHOULD HELP TO FOCUS DEVELOPING CLOUDS OVER THE LAKE INTO NORTHEAST IL BY MID MORNING...AND LIKELY TOWARD GYY AS WELL. THESE LAKE ENHANCED CLOUDS ARE PRESENTLY FAVORED TO BE AT OR ABOVE 2000 FT BY THE TIME THEY ARRIVE AT THE TERMINALS...BUT AT ONSET SOME COULD BE BELOW 2000 FT. THAT SHOULD BE BRIEF IF THAT OCCURS. CLOUDS SHOULD GRADUALLY BECOME MORE SCATTERED THROUGH THE AFTERNOON AS THE COLD AIR ADVECTION COMPONENT OVER THE WATER WEAKENS. THE HIGH PRESSURE WILL SETTLE SOUTHWARD OVER THE AREA THIS EVENING...WITH RETURN FLOW DEVELOPING ON MONDAY. //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN BROKEN CLOUDS BETWEEN 2000 AND 3500 FT. MEDIUM CONFIDENCE IN TIMING. LOW CONFIDENCE IN ANY CIGS BELOW 2000 FT. * HIGH CONFIDENCE IN WIND DIRECTIONAL TRENDS. MEDIUM CONFIDENCE IN GUSTS. * LOW CONFIDENCE IN ANY RETURNING BROKEN CIGS TONIGHT. //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT SUN SEP 30 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN SEP 30 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER THE ERN GREAT LAKES AND A RIDGE UPSTREAM FROM MN TO NEAR JAMES BAY. SINCE THE LOW HAS EDGED SLIGHTLY TO THE WEST...COOLER AIR AND AN INCREASE IN LOW LEVEL MOISTURE HAS ALSO PUSHED WESTWARD THROUGH UPPER MI WITH SOME PATCHY LOW CLOUDS...ESPECIALLY IN LOCATIONS FAVORED BY NE UPSLOPE FLOW. FARTHER UPSTREAM...A SHRTWV AND NOSE OF A 250-300 JET STREAK WAS MOVING THROUGH SRN ALBERTA. AT THE SFC...A RIDGE EXTENDED FROM NRN QUEBEC TO THE SOUTHWEST INTO THE NRN GREAT LAKES. TODAY...EXPECT ANY LINGERING LOWER CLOUDS TO THIN OUT BY MID TO LATE MORNING WITH INCREASING DAYTIME HEATING. OTHERWISE...HIGH PRES WILL CONTINUE TO DOMINATE THE REGION WITH MOSTLY SUNNY SKIES AND LIGHT ERLY WINDS. WITH LITTLE CHANGE IN THE POSITION OF THE 925-850 MB THERMAL TROUGH...TEMPS SHOULD BE SIMILAR TO SATURDAY WITH MAX READINGS IN THE MID TO UPPER 60S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. TONIGHT...THE SRN CANADA SHRTWV WILL MOVE THROUGH THE NRN PLAINS AND WILL HELP NUDGE THE BLOCKY DOWNSTREAM RIDGE/TROUGH TO THE EAST. HOWEVER...MDLS/ENSEMBLE CONSENSUS SUGGESTS THAT ANY PCPN WITH THE TROUGH SHOULD REMAIN WEST OF LAKE SUPERIOR. AN INCREASE IN SRLY WINDS AND SOME MID AND HIGH CLOUDS SHOULD KEEP TEMPS FROM FALLING OFF AS MUCH. LOOK FOR MIN READINGS FROM THE UPPER 30S TO AROUND 40 INLAND AND CLOSE TO 50 FOR THE GREAT LAKES AND WHERE DOWNSLOPE SSW FLOW PREVAILS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 510 AM EDT SUN SEP 30 2012 AT 12Z MON THERE WILL BE AN UPPER RIDGE OVER THE CWA...WITH A SHORTWAVE TROUGH FROM WRN HUDSON BAY TO WRN MN. AHEAD OF THE SHORTWAVE...A SFC TROUGH WILL BE OVER WRN LAKE SUPERIOR. MODELS NOT SHOWING MUCH MOISTURE WITH THE SYSTEM...OR MUCH QPF...BUT MOST DO SHOW SOME LIGHT PRECIP ASSOCIATED WITH A NARROW BAND OF LOW LEVEL MOISTURE OVER PORTIONS OF THE CWA AS THE SHORTWAVE PASSES MON INTO MON NIGHT. WILL KEEP SLIGHT CHANCE POPS IN THE FORECAST FOR THIS TIME. ATTENTION THEN TURNS TO A MUCH STRONGER SYSTEM THAT MODELS SHOW ENTERING THE NRN PLAINS TUE NIGHT AND STRENGTHENING SOMEWHERE IN THE REGION AROUND THE CWA THU. MODELS THEN SHOW REINFORCING UPPER ENERGY AND COLD AIR MOVING IN FRI INTO THE WEEKEND. OVERALL...THE FORECAST DURING THIS TIME IS VERY UNCERTAIN AND QUITE TRICKY. THERE IS SUBSTANTIAL RUN TO RUN VARIABILITY WITH MOST MODELS AS WELL AS MODEL DISAGREEMENT...SO FORECAST CONFIDENCE IS LOW. THE OVERALL IDEA SHOWN BY MODELS IS THAT THE UPPER TROUGH WILL DEEPEN AND CLOSE OFF SOMEWHERE IN THE REGION THU...AND THEN MOVE NE TO JAMES BAY OR QUEBEC FRI. NW LOW LEVEL WINDS AND 850MB TEMPS AS LOW AS -8C BEHIND THE SYSTEM WOULD BE FAVORABLE FOR LAKE EFFECT RAIN/SNOW FRI INTO SAT. MODELS HAVE BEEN SHOWING A GENERAL NORTHERLY TREND WITH THE LOW TRACK...MORE TOWARD THE ECMWF WHICH HAS SHOWN BETTER CONTINUITY. NOW THE LATEST RUN OF THE GFS (00Z/30) SLOWED THE EVOLUTION OF THE SYSTEM BY 12-18 HOURS FROM THE PREVIOUS RUN. WITH THE SYSTEM CURRENTLY S OF THE ALEUTIAN ISLANDS AT AROUND LAT 45N LON 160W IT IS NOT BEING SAMPLED BY TRADITIONAL UPPER AIR NETWORK...SO HOPEFULLY CONFIDENCE WILL BE IMPROVED WHEN THE SYSTEM MOVES INTO THE OBSERVATION NETWORK OF WRN CANADA AROUND 00Z TUE. IT IS IMPORTANT TO POINT THAT THERE IS A VERY WIDE GAMUT OF POSSIBLE REALITIES RESULTING FROM DIFFERENT PATHS THIS SYSTEM MAY TAKE. IF THE SYSTEM GOES MORE S OF THE CWA...SE TO NE GALES AND A WETTER/SNOWIER FORECAST MAY RESULT. IF THE SYSTEM GOES N OF THE CWA...W GALES AND A DRIER FORECAST MAY RESULT...WITH THE POSSIBILITY OF THUNDERSTORMS ALONG THE ATTENDANT COLD FRONT. IF THE SYSTEM GOES OVER THE CWA...A COMBINATION OF THE PREVIOUS SCENARIOS MAY RESULT. OF COURSE...THERE IS ALSO THE POSSIBILITY THAT THE SYSTEM ENDS UP BEING SIGNIFICANTLY WEAKER (OR EVEN STRONGER) THAN WHAT THE MODELS CURRENTLY SHOW. AM REALLY NOT CERTAIN WHAT WILL HAPPEN...BUT AM LEANING TOWARD THE NRN TRACK OF THE MORE PERSISTENT ECMWF AND FORECAST PERSISTENCE WITH THIS SYSTEM. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 737 AM EDT SUN SEP 30 2012 ANY LEFTOVER SHALLOW FOG SHOULD DISSIPATE BY AROUND 13Z THIS MORNING WITH THE ONSET OF DAYTIME HEATING. OTHERWISE...EXPECT MAINLY VFR CONDITIONS THIS FCST PERIOD AT ALL 3 TAF SITES WITH DRY HI PRES OVER ONTARIO DOMINATING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN SEP 30 2012 HIGH PRESSURE AND A WEAK PRESSURE GRADIENT WILL PERSIST TODAY. SRLY WINDS WILL INCREASE INTO THE 10 TO 20 KT RANGE TONIGHT AHEAD OF A TROUGH MOVING TOWARD THE REGION. WINDS WILL VEER TO THE WEST MONDAY AND THEN TO THE NORTH MONDAY NIGHT BUT SHOULD REMAIN AT OR BELOW 20 KT. HIGH PRESSURE WILL AGAIN DOMINATE TUESDAY WITH RELATIVELY LIGHT WINDS. A LOW PRESSURE SYSTEM LIFTING INTO NORTHWEST ONTARIO WILL PUSH A COLD FRONT THROUGH LAKE SUPERIOR THURSDAY WITH STRONG WRLY WINDS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
611 AM CDT SUN SEP 30 2012 .AVIATION...12Z TAF FOR KGRI. VFR CONDITIONS WILL PREVAIL DURING THE VALID TIME PERIOD. AS HIGH CLOUDS CONTINUE TO EXIT THE REGION...MOSTLY CLEAR SKIES WILL BE REALIZED OVER THE TERMINAL SITE TODAY. SHORTLY AFTER MIDNIGHT...NAM FORECAST SOUNDINGS SUGGEST CLOUDS WILL BEGIN TO ROLL IN OVER THE TAF SITE IN ASSOCIATION WITH AN APPROACHING COLD FRONT. SHOWERS ARE EXPECTED TO FORM OVER WESTERN NEBRASKA THIS AFTERNOON...BUT THESE SHOWERS ARE NOT EXPECTED TO IMPACT THE TERMINAL SITE. && .PREV DISCUSSION... /ISSUED 406 AM CDT SUN SEP 30 2012/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MAIN FORECAST CONCERN IS ISOLATED THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON/EVENING... FOLLOWED BY THE PASSAGE OF A COLD FRONT SHORTLY THEREAFTER. WEAK SURFACE HIGH PRESSURE CENTERED NEAR HILL CITY KANSAS THIS MORNING HAS KEPT WINDS LIGHT...WITH ONLY SOME HIGH CLOUDS SCRAPING THE SOUTHEAST 1/3 OF THE FORECAST AREA. TEMPERATURES WARMER IN THE CLOUDY AREAS...AS OPPOSED TO CLOUD FREE REGIONS. ONE EARLY...ALTHOUGH MINOR CONCERN...MAY BE A BIT OF FOG IN THE FAR SOUTHWEST/WESTERN FORECAST AREA. LATEST HRRR DATA IS SHYING AWAY FROM ANY FOG OR LOW CLOUDS IN OUR FORECAST AREA...OPTING INSTEAD JUST TO THE WEST WHERE SOUTHERLY FLOW HAS ALLOWED FOR A LITTLE BETTER MOISTURE RETURN. MOST LIKELY THIS STUFF WOULDN/T GET GOING UNTIL CLOSE TO SUNRISE...SO ITS A GAME TIME DECISION WHETHER ITS WORTH EVEN BEING PART OF THE FORECAST. RIGHT NOW...ITS NOT LOOKING TO LIKELY TO FORM. THE MAIN STORY REST OF THE DAY IS WHETHER THE WESTERN PART OF THE FORECAST CAN SHARE IN SOME ISOLATED SHOWERS/THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. WEAK SURFACE CONVERGENCE ALONG A BOUNDARY STARTS TO PUSHING THE FAR WESTERN SECTION OF THE FORECAST ABOUT MID AFTERNOON. THIS COINCIDES WITH NARROW AXIS OF MOISTURE AND SURFACE INSTABILITY BRIEFLY ABOVE 1000 J/KG. STEEP MID LEVEL LAPSE RATES ALSO SET UP. THERE LIKELY WILL BE SOME HIGH BASED SHOWERS/ISOLATED THUNDERSTORMS FORMING JUST TO THE WEST OF THE FORECAST AREA AROUND 3-4 PM...AND THEN GRADUALLY MIGRATE EAST. HAVE CONTINUED WITH THE 20-30% CHANCE OF RAIN...NOT SO MUCH FOR UNCERTAINTY ON CONVECTIVE ACTIVITY...BUT KEPT THINGS ON THE LOW SIDE WITH LARGE LOW LEVEL DEWPOINT DEPRESSIONS AND CLASSIC INVERTED V SOUNDINGS. BOTH SUGGEST LIMITED RAINFALL...BUT SOME WIND GUST POTENTIAL TO NEAR SEVERE LEVELS. HAVE INCLUDED SOME CHANCE INTO THE EARLY EVENING AS FAR EAST AS HIGHWAY 281...ALTHOUGH THAT MAY WELL BE STRETCHING IT WITH STORM MOTIONS PROBABLY AROUND 10KTS OR SO. LATEST MODELS HAVE FAVORED A LITTLE FURTHER WEST PROFILE...SO KEPT THE BEST SHOT FOR RAIN THERE. WELL...ONCE THAT STUFF WRAPS BY LATE EVENING...ATTENTION TURNS TO ONCOMING COLD FRONT LATE TONIGHT AND EARLY MONDAY. PRETTY STRONG PRESSURE RISES AS THE FRONT PASSES...SO EXPECT THE WIND TO PICK UP PRETTY STEADY BY LATE TONIGHT. GOOD MOMENTUM TRANSFER WILL CONTINUE ALL DAY MONDAY WITH NEARLY UNIDIRECTIONAL FLOW GIVING US THE FIRST BREEZY/WINDY DAY...SINCE THE LAST COLD FRONT A FEW DAYS AGO. MODELS TRY TO SQUEEZE OUT SOME LIGHT SHOWERS...PROBABLY SPRINKLES. NONE THE LESS...HAVE WORKED IN TANDEM WITH OTHER OFFICES TO INCLUDE A SLIGHT CHANCE OF LIGHT SHOWERS MONDAY MORNING...BEFORE SUNSHINE TAKES OVER LATER. TEMPERATURES WILL NOT ONLY FEEL COOLER DUE TO THE NORTH WIND...BUT ACTUALLY BE COOLER DURING THE DAY MONDAY. NOT MUCH ELSE TO WORRY ABOUT MONDAY NIGHT THROUGH TUESDAY NIGHT... WITH A COOL NIGHT MONDAY NIGHT...GIVING WAY TO A REALLY NICE AND MILD DAY TUESDAY WITH SUNSHINE AND LIGHT WINDS. LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. A COLD FRONT PROGGED TO TRANSITION THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY WILL PROVE TO BE THE MOST CHALLENGING ASPECT OF THE EXTENDED FORECAST. CHALLENGES WILL RESULT IN PRECIPITATION TIMING/COVERAGE AND TEMPERATURES BOTH AHEAD AND BEHIND THE COLD FRONT. PRECIP CHANCES WILL ALSO BE REALIZED TOWARDS THE END OF THE LONG TERM. A COLD FRONT WILL EXTEND DOWN INTO THE CENTRAL PLAINS ON THURSDAY FROM FROM AN ASSOCIATED UPPER LEVEL TROUGH FORECAST TO PASS THROUGH THE NORTHERN PLAINS. RETURN FLOW IN THE LOWER LEVELS AHEAD OF THIS FRONTAL BOUNDARY SHOULD ADVECT ENOUGH MOISTURE INTO THE CENTRAL PLAINS TO HELP AID IN THE DEVELOPMENT OF SOME STRATIFORM RAIN ACROSS THE OUTLOOK AREA. FORECAST SOUNDINGS SUGGEST A MOIST ATMOSPHERIC PROFILE BEGINNING AROUND MIDNIGHT ON WEDNESDAY AND CONTINUING THROUGH THE MORNING HOURS OF THURSDAY. PRECIPITATION TIMING WILL RELY SOLELY ON THE TIMING OF THE COLD FRONT...BUT CURRENT ANALYSIS LEADS TO PRECIP BEGINNING LATE WEDNESDAY NIGHT AND CONTINUING THROUGH THURSDAY MORNING BEHIND THE COLD FRONT. NO SEVERE WEATHER IS ANTICIPATED. THE BIGGEST CHANGE IN THE FORECAST WAS WEDNESDAY HIGH TEMPERATURES...WHICH WILL BE NEAR 80 DEGREES AHEAD OF THE FRONT FOR MOST OF THE OUTLOOK AREA. THIS CHANGE IS MAINLY DUE TO THE TIMING OF THE FRONT BEING A LITTLE SLOWER THAN PREVIOUSLY FORECAST. FURTHERMORE...850MB TEMPS ALSO SUGGEST HIGHER TEMPERATURES THAN THE OUTPUT FROM ALLBLEND. THURSDAY HIGH TEMPERATURES AND FRIDAY MORNING LOW TEMPERATURES HAVE BEEN RATHER TRICKY WITH THE PASSAGE OF THE FRONTAL BOUNDARY OVER THE LAST COUPLE OF DAYS. SEEMS AS THOUGH THE MODELS MAY HAVE FINALLY SETTLED ON A SOLUTION. THE PAST SEVERAL DAYS HAVE SHOWN A GENERAL DECREASE IN TEMPERATURES ACROSS THE CWA FOR THURSDAY HIGH TEMPERATURES AND THE OVERNIGHT LOWS...BUT TEMPERATURES ARE NOW NEARLY CONSISTENT WITH THE PREVIOUS FORECAST. THURSDAY WILL BE BELOW NORMAL FOR HIGHS AS UPPER 50S AND LOWER 60S ARE FORECAST. IN FACT...THE REST OF THE LONG TERM IS FORECAST TO EXPERIENCE BELOW NORMAL TEMPERATURES FOR THIS TIME OF YEAR. THURSDAY NIGHT LOW TEMPERATURES ARE STILL FLIRTING WITH FROST POTENTIAL. WILL NEED TO MONITOR THIS OVER THE NEXT COUPLE OF DAYS. A FROST ADVISORY MIGHT HAVE SOME CREDIBILITY ACROSS NORTHERN PARTS OF THE CWA NEXT WEEK. THERE WILL BE A CHANCE FOR PRECIPITATION FRIDAY NIGHT AND INTO SATURDAY AS ANOTHER CONVERGENCE ZONE SETS UP OVER THE CENTRAL PLAINS WITH FORECAST SOUNDINGS SUGGESTING A MOIST ATMOSPHERIC PROFILE. AGAIN...SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...NOAA/NWS/MORITZ LONG TERM/AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 AM EDT SUN SEP 30 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEK AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. WEATHER WILL REMAIN UNSETTLED THROUGH MID WEEK AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES NORTHEAST ACROSS THE TENNESSEE VALLEY. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SUNDAY...THE LAST OF THE SHOWERS ARE DISSIPATING AS THEY MOVE INTO WILMINGTON EARLY THIS MORNING. DRY WEATHER IS EXPECTED THE REMAINDER OF THE DAY...ALTHOUGH THE 06Z MODELS CONTINUE TO DIVERGE ON HOW MUCH CLEARING AND HEATING WE WILL END UP SEEING THIS AFTERNOON. THE 06Z NAM AND ESPECIALLY 09Z RUC ARE QUITE A BIT WARMER THAN THE 06Z GFS. INFRARED BRIGHTNESS TEMPERATURES ACROSS NORTH CAROLINA AWAY FROM THE CIRRUS DECK CONTINUE TO READ 8 DEGREES CELSIUS...INDICATIVE OF A CLOUD TOP 6500-7000 FT AGL. IF THIS IS CORRECT WE WILL SEE A VERY SLOW BURNOFF OF CLOUDS TODAY...WITH OVERCAST CONDITIONS PERHAPS LINGERING INTO THE AFTERNOON HOURS. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... THE SURFACE COLD FRONT HAS PUSHED INTO NORTHEASTERN SOUTH CAROLINA ROUGHLY FROM MYRTLE BEACH TO NEAR KINGSTREE. WAVES OF SHOWERS AND EMBEDDED THUNDERSTORMS NORTH OF THE BOUNDARY ARE FEEDING OFF 500-750 J/KG OF ELEVATED INSTABILITY WITH SYNOPTIC LIFT PROVIDED BY AN UPPER-LEVEL DIVERGENT PATTERN IN THE RIGHT-ENTRANCE REGION OF A 300 MB JET STREAK OVER EASTERN NORTH CAROLINA. AS THIS JET STREAK MOVES OFFSHORE IN THE NEXT FEW HOURS LOOK FOR SHOWERS AND STORMS TO MOVE OFFSHORE AND/OR DISSIPATE. LOW STRATUS CLOUDS NORTH OF THE FRONT WILL PERSIST THROUGH SUNRISE AND POSSIBLY FOR SEVERAL HOURS BEYOND. IN FACT OUR BIGGEST FORECAST CHALLENGE FOR THE DAYLIGHT HOURS IS DETERMINING HOW QUICKLY THESE LOW CLOUDS DISSIPATE...WITH MAJOR IMPLICATIONS ON OUR HIGH TEMPERATURES. GFS AND NAM FORECAST SOUNDINGS FOR 18Z TODAY DO NOT NECESSARILY AGREE WITH SATELLITE DERIVED ESTIMATES OF THE STRATUS CLOUD TOPS ACROSS NORTH CAROLINA CURRENTLY. GIVEN THE DEPTH OF MOISTURE OBSERVED ON THE 00Z GSO AND RNK SOUNDINGS (WHICH DO AGREE WITH THE SATELLITE ESTIMATES OF CLOUD TOPS) I HAVE LOWERED OUR HIGH TEMPERATURE FORECASTS BY SEVERAL DEGREES TODAY...NOW RANGING FROM THE MID TO UPPER 70S...BUT CONSIDERABLE UNCERTAINTY REMAINS. SYNOPTIC LOW PRESSURE DEVELOPING ALONG THE TX GULF COAST WILL MOVE EAST INTO MISSISSIPPI TONIGHT. INCREASING SOUTHERLY LOW LEVEL FLOW ALONG THE SOUTH ATLANTIC COAST WILL PUSH THE FRONT NORTHWARD. ABOVE THE FRONTAL SURFACE THE SOUTHERLY WINDS WILL ADVECT A WARM AND HUMID AIRMASS OVERHEAD TONIGHT...PRODUCING AN ALMOST WINTER-LIKE ISENTROPIC LIFT REGIME. THERE ARE NO FAVORABLY POSITIONED UPPER LEVEL JETS TO ASSIST LIFT AND THEREFORE DESPITE FAIRLY HIGH POPS IN OUR FORECAST (50-60 PERCENT TONIGHT) I HAVE KEPT QPF VALUES RATHER LOW. LOWS SHOULD FALL INTO THE MID 60S FOR MOST AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...STALLED FRONT WILL LIFT NORTH OF THE AREA EARLY MON AS A WARM FRONT. THIS WILL RESULT IN PRECIP TRANSITIONING FROM LIGHT RAIN TO DEEPER ISOLATED CONVECTION IN THE AFTERNOON. THE BIG QUESTION FOR MONDAY WILL BE HOW MUCH LOW LEVEL INSTABILITY WILL BE PRESENT. REGION SHOULD BE SOLIDLY IN THE WARM SECTOR BUT CLOUD COVER WILL LIMIT DIURNAL HEATING. FLOW ALOFT MAY BE SLIGHTLY DIVERGENT BUT LIKELY NOT ENOUGH TO SIGNIFICANTLY ENHANCE UPWARD MOTION. GIVEN THE LACK OF ANY SIGNIFICANT TRIGGERS AND LIMITED DIURNAL INSTABILITY WILL MAINTAIN HIGH CHANCE POP MON. MON NIGHT SURFACE LOW ASSOCIATED WITH THE 5 TROUGH OVER THE MS VALLEY STARTS TO SLOWLY LIFT NORTH...KEEPING THE SOUTHEAST IN THE WARM SECTOR. DEEP SOUTHERLY FLOW AND ABUNDANT MOISTURE COMBINED WITH INCREASING DIVERGENCE ALOFT WILL LEAD TO AN INCREASE IN CONVECTION LATE MON NIGHT...ESPECIALLY OFFSHORE. SURFACE LOW CONTINUE TO TRACK NORTH TUE INTO TUE NIGHT...MOVING ACROSS THE TN/KY/OH VALLEYS AND ENDING UP OVER THE EASTERN GREAT LAKES AT THE END OF THE PERIOD. THE COMBINATION OF SURFACE LOW LIFTING NORTH-NORTHEAST AND THE GRADUAL EASTWARD MOVEMENT OF THE 5H TROUGH HELPS PUSH A WEAK COLD FRONT ACROSS THE REGION TUE NIGHT. AHEAD OF THE FRONT DEEP MOISTURE...PRECIPITABLE WATER VALUES CLIMB OVER 2 INCHES TUE...ALONG WITH LOW LEVEL SPEED CONVERGENCE AND WEAKLY DIVERGENT FLOW ALOFT HELPS GENERATE AFTERNOON SHOWERS AND THUNDERSTORMS. FRONT ITSELF DOES NOT LOOK VERY ACTIVE AND ITS ARRIVAL WILL NOT BE ACCOMPANIED BY SIGNIFICANT COLD ADVECTION...THOUGH DEEP DRY AIR WILL START TO BUILD OVER THE SOUTHEAST AS THE PERIOD ENDS. ALTHOUGH CLOUD COVER AND PRECIP ARE EXPECTED BOTH DAYS THE WARM SOUTHERLY FLOW WILL HELP KEEP HIGHS ABOVE CLIMO. LOWS WILL ALSO BE ABOVE CLIMO...HELPED BY BOTH CLOUD COVER AND WINDS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...DEEP MOISTURE AND STALLED FRONT LINGERING ALONG OR JUST OFF THE COAST WED WILL MAINTAIN THE CHANCE OF PRECIP EARLY IN THE PERIOD. HIGHEST POP WED WILL BE ALONG THE COAST WITH MORE OF A DIURNAL TREND...THOUGH NOCTURNAL CONVECTION OVER THE WATERS WED NIGHT COULD MOVE ONSHORE AS IT DISSIPATES. MID LEVEL TROUGH MOVING THROUGH THE NORTHEAST AND SOUTHEASTERN CANADA PUSHES A SURFACE LOW OFF THE NEW ENGLAND COAST. AS THIS LOW MOVES EAST IT HELPS PULL THE FRONT STALLED JUST OFF THE COAST FARTHER EAST. SOME DIFFERENCES BETWEEN THE GFS/ECMWF SOLUTIONS WITH THE STALLED FRONT...THE GFS IS ADVERTISING A SLOWER SOLUTION WHICH HOLDS ONTO POP ALONG THE COAST THU AND THU NIGHT. INHERITED A SLIGHT CHANCE THU...WILL TRIM POP INLAND BUT HOLD ONTO SLIGHT CHANCE AT THE COAST. LACK OF ANY REAL COLD ADVECTION OR CLOUD COVER RESULTS IN HIGHS SEVERAL DEGREES ABOVE CLIMO. LOW ALSO END UP ABOVE CLIMO...THOUGH ONLY BY A FEW DEGREES AS DRIER AIR...ESPECIALLY INLAND...AND LIGHT WINDS ALLOW FOR SOME RADIATIONAL COOLING. SURFACE HIGH PRESSURE AND MUCH DRIER AIR BUILDS OVER THE REGION FRI AND SAT. COMBINATION OF DEEP WEST TO NORTHWEST FLOW AND LOW LEVEL NORTHEAST FLOW WILL KEEP THE REGION DRY WITH DOWNSLOPE FLOW HELPING KEEP HIGHS SLIGHTLY ABOVE CLIMO. DRY AIR AND RADIATIONAL COOLING WILL RESULT IN LOWS VERY CLOSE TO CLIMO TO END THE PERIOD. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 12Z...WIDESPREAD IFR CEILINGS WILL BE THE RULE FOR THE FIRST FEW HOURS THIS MORNING...WITH SOME ISOLATED LOW VISIBILITIES. THE MYRTLES ARE ON THE FRINGE OF THE IFR AND MAY COME UP FIRST. MOST OF THE DEEP MOISTURE HAS RETREATED TO THE SOUTH AND EAST...WITH LITTLE CHANCE FOR CONVECTION TODAY AS THE FRONT STALLS JUST TO THE SOUTH OF THE REGION. TIME HEIGHT SHOWS A VERY THIN LAYER OF STRATA CU BY EARLY AFTERNOON...IT WILL PROBABLY SCATTER. TONIGHT...WARM FRONT WAVES BACK NORTH WITH PRECIPITATION RETURNING AFTER 03Z. CEILINGS WILL ALSO DRIVE BACK DOWN TO IFR WITH ABUNDANT LOW LEVEL MOISTURE. EXTENDED OUTLOOK...UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONT COULD PRODUCE PERIODS OF IFR CONDITIONS ACROSS THE AREA THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SUNDAY...THE FRONT CONTINUES TO PRESS SOUTHWARD ALONG THE SC COAST AND SHOULD BE MOVING INTO GEORGETOWN SHORTLY. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 330 AM FOLLOWS... A COLD FRONT HAS PUSHED SOUTH THROUGH MYRTLE BEACH AND SHOULD STALL OUT LATER TODAY JUST SOUTH OF GEORGETOWN. THERE IS NOT A STRONG SURGE OF NORTH WINDS BEHIND THIS FRONT...AND WIND SPEEDS 10 KT OR LESS ARE EXPECTED TO PREDOMINATE. WAVES OF SHOWERS AND THUNDERSTORMS NORTH OF THE SURFACE FRONT ARE BEING PRODUCED BY AN UPPER LEVEL DISTURBANCE MOVING OFF THE NC COAST AND SHOULD DIMINISH AROUND DAYBREAK...AFFECTING MAINLY THE CAPE FEAR AREA. FOR TONIGHT THE FRONT WILL BEGIN TO LIFT BACK TO THE NORTH IN RESPONSE TO DEVELOPING LOW PRESSURE ALONG THE CENTRAL GULF COAST. THE FRONT MAY REACH MYRTLE BEACH BY DAYBREAK MONDAY...WITH WINDS SOUTH OF THE FRONT SHIFTING TO THE SOUTH...WITH LIGHTER NORTHEAST TO EAST WINDS EXPECTED NORTH OF THE BOUNDARY. SEAS AT THE NEARSHORE AND OFFSHORE BUOYS ARE ONLY 2 FEET CURRENTLY...AND LITTLE CHANGE IS EXPECTED THROUGH TONIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...WARM FRONT WILL LIFT NORTH OF THE WATERS MON WITH SOUTHERLY FLOW DEVELOPING. RIGHT BEHIND THE FRONT WINDS WILL BE EAST-SOUTHEAST...BUT DURING THE AFTERNOON WINDS BECOME MORE SOUTHERLY. SLIGHT INCREASE IN GRADIENT WILL SEE WINDS INCREASE INTO THE 10 TO 15 KT RANGE ON MON. FURTHER TIGHTENING OF THE GRADIENT IS POSSIBLE MON NIGHT INTO TUE WHICH MAY RESULT IN A SOLID 15 KT TUE INTO TUE NIGHT. LATE IN THE PERIOD WEAK COLD FRONT MOVES OFF THE COAST. BEHIND THE FRONT WINDS BECOME WEST-SOUTHWEST AROUND 10 KT AS GRADIENT RELAXES AND COLD ADVECTION FAILS TO DEVELOP. SEAS START OUT 2 TO 3 FT BUT BUILD TO 3 TO 4 FT LATE MON NIGHT AND 3 TO 5 FT TUE INTO TUE NIGHT BEFORE SOUTHWEST FLOW AND REDUCTION IN SPEEDS RESULTS IN A SLIGHT DECREASE IN SEAS. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...FRONT STALLED ACROSS THE WATERS AND LACK OF ANY SIGNIFICANT GRADIENT WILL KEEP SPEEDS AROUND 10 KT OR LESS WED...WITH A SOUTHWESTERLY COMPONENT. WED NIGHT HIGH PRESSURE CENTERED TO THE WEST SLIDES NORTHEAST AS THE STALLED FRONT STARTS TO PUSH EAST. WINDS VEER TO NORTHWEST LATE WED NIGHT AND CONTINUE VEERING TO NORTHEAST THU AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. LIGHT AND CHANGEABLE WINDS DURING THE PERIOD WILL RESULT IN SEAS FALLING THROUGH THE PERIOD. 2 TO 4 FT WED DECREASING TO 2 TO 3 FT THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...III AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
634 AM EDT SUN SEP 30 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEK AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. WEATHER WILL REMAIN UNSETTLED THROUGH MID WEEK AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES NORTHEAST ACROSS THE TENNESSEE VALLEY. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SUNDAY...THE LAST OF THE SHOWERS ARE DISSIPATING AS THEY MOVE INTO WILMINGTON EARLY THIS MORNING. DRY WEATHER IS EXPECTED THE REMAINDER OF THE DAY...ALTHOUGH THE 06Z MODELS CONTINUE TO DIVERGE ON HOW MUCH CLEARING AND HEATING WE WILL END UP SEEING THIS AFTERNOON. THE 06Z NAM AND ESPECIALLY 09Z RUC ARE QUITE A BIT WARMER THAN THE 06Z GFS. INFRARED BRIGHTNESS TEMPERATURES ACROSS NORTH CAROLINA AWAY FROM THE CIRRUS DECK CONTINUE TO READ 8 DEGREES CELSIUS...INDICATIVE OF A CLOUD TOP 6500-7000 FT AGL. IF THIS IS CORRECT WE WILL SEE A VERY SLOW BURNOFF OF CLOUDS TODAY...WITH OVERCAST CONDITIONS PERHAPS LINGERING INTO THE AFTERNOON HOURS. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... THE SURFACE COLD FRONT HAS PUSHED INTO NORTHEASTERN SOUTH CAROLINA ROUGHLY FROM MYRTLE BEACH TO NEAR KINGSTREE. WAVES OF SHOWERS AND EMBEDDED THUNDERSTORMS NORTH OF THE BOUNDARY ARE FEEDING OFF 500-750 J/KG OF ELEVATED INSTABILITY WITH SYNOPTIC LIFT PROVIDED BY AN UPPER-LEVEL DIVERGENT PATTERN IN THE RIGHT-ENTRANCE REGION OF A 300 MB JET STREAK OVER EASTERN NORTH CAROLINA. AS THIS JET STREAK MOVES OFFSHORE IN THE NEXT FEW HOURS LOOK FOR SHOWERS AND STORMS TO MOVE OFFSHORE AND/OR DISSIPATE. LOW STRATUS CLOUDS NORTH OF THE FRONT WILL PERSIST THROUGH SUNRISE AND POSSIBLY FOR SEVERAL HOURS BEYOND. IN FACT OUR BIGGEST FORECAST CHALLENGE FOR THE DAYLIGHT HOURS IS DETERMINING HOW QUICKLY THESE LOW CLOUDS DISSIPATE...WITH MAJOR IMPLICATIONS ON OUR HIGH TEMPERATURES. GFS AND NAM FORECAST SOUNDINGS FOR 18Z TODAY DO NOT NECESSARILY AGREE WITH SATELLITE DERIVED ESTIMATES OF THE STRATUS CLOUD TOPS ACROSS NORTH CAROLINA CURRENTLY. GIVEN THE DEPTH OF MOISTURE OBSERVED ON THE 00Z GSO AND RNK SOUNDINGS (WHICH DO AGREE WITH THE SATELLITE ESTIMATES OF CLOUD TOPS) I HAVE LOWERED OUR HIGH TEMPERATURE FORECASTS BY SEVERAL DEGREES TODAY...NOW RANGING FROM THE MID TO UPPER 70S...BUT CONSIDERABLE UNCERTAINTY REMAINS. SYNOPTIC LOW PRESSURE DEVELOPING ALONG THE TX GULF COAST WILL MOVE EAST INTO MISSISSIPPI TONIGHT. INCREASING SOUTHERLY LOW LEVEL FLOW ALONG THE SOUTH ATLANTIC COAST WILL PUSH THE FRONT NORTHWARD. ABOVE THE FRONTAL SURFACE THE SOUTHERLY WINDS WILL ADVECT A WARM AND HUMID AIRMASS OVERHEAD TONIGHT...PRODUCING AN ALMOST WINTER-LIKE ISENTROPIC LIFT REGIME. THERE ARE NO FAVORABLY POSITIONED UPPER LEVEL JETS TO ASSIST LIFT AND THEREFORE DESPITE FAIRLY HIGH POPS IN OUR FORECAST (50-60 PERCENT TONIGHT) I HAVE KEPT QPF VALUES RATHER LOW. LOWS SHOULD FALL INTO THE MID 60S FOR MOST AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...STALLED FRONT WILL LIFT NORTH OF THE AREA EARLY MON AS A WARM FRONT. THIS WILL RESULT IN PRECIP TRANSITIONING FROM LIGHT RAIN TO DEEPER ISOLATED CONVECTION IN THE AFTERNOON. THE BIG QUESTION FOR MONDAY WILL BE HOW MUCH LOW LEVEL INSTABILITY WILL BE PRESENT. REGION SHOULD BE SOLIDLY IN THE WARM SECTOR BUT CLOUD COVER WILL LIMIT DIURNAL HEATING. FLOW ALOFT MAY BE SLIGHTLY DIVERGENT BUT LIKELY NOT ENOUGH TO SIGNIFICANTLY ENHANCE UPWARD MOTION. GIVEN THE LACK OF ANY SIGNIFICANT TRIGGERS AND LIMITED DIURNAL INSTABILITY WILL MAINTAIN HIGH CHANCE POP MON. MON NIGHT SURFACE LOW ASSOCIATED WITH THE 5 TROUGH OVER THE MS VALLEY STARTS TO SLOWLY LIFT NORTH...KEEPING THE SOUTHEAST IN THE WARM SECTOR. DEEP SOUTHERLY FLOW AND ABUNDANT MOISTURE COMBINED WITH INCREASING DIVERGENCE ALOFT WILL LEAD TO AN INCREASE IN CONVECTION LATE MON NIGHT...ESPECIALLY OFFSHORE. SURFACE LOW CONTINUE TO TRACK NORTH TUE INTO TUE NIGHT...MOVING ACROSS THE TN/KY/OH VALLEYS AND ENDING UP OVER THE EASTERN GREAT LAKES AT THE END OF THE PERIOD. THE COMBINATION OF SURFACE LOW LIFTING NORTH-NORTHEAST AND THE GRADUAL EASTWARD MOVEMENT OF THE 5H TROUGH HELPS PUSH A WEAK COLD FRONT ACROSS THE REGION TUE NIGHT. AHEAD OF THE FRONT DEEP MOISTURE...PRECIPITABLE WATER VALUES CLIMB OVER 2 INCHES TUE...ALONG WITH LOW LEVEL SPEED CONVERGENCE AND WEAKLY DIVERGENT FLOW ALOFT HELPS GENERATE AFTERNOON SHOWERS AND THUNDERSTORMS. FRONT ITSELF DOES NOT LOOK VERY ACTIVE AND ITS ARRIVAL WILL NOT BE ACCOMPANIED BY SIGNIFICANT COLD ADVECTION...THOUGH DEEP DRY AIR WILL START TO BUILD OVER THE SOUTHEAST AS THE PERIOD ENDS. ALTHOUGH CLOUD COVER AND PRECIP ARE EXPECTED BOTH DAYS THE WARM SOUTHERLY FLOW WILL HELP KEEP HIGHS ABOVE CLIMO. LOWS WILL ALSO BE ABOVE CLIMO...HELPED BY BOTH CLOUD COVER AND WINDS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...DEEP MOISTURE AND STALLED FRONT LINGERING ALONG OR JUST OFF THE COAST WED WILL MAINTAIN THE CHANCE OF PRECIP EARLY IN THE PERIOD. HIGHEST POP WED WILL BE ALONG THE COAST WITH MORE OF A DIURNAL TREND...THOUGH NOCTURNAL CONVECTION OVER THE WATERS WED NIGHT COULD MOVE ONSHORE AS IT DISSIPATES. MID LEVEL TROUGH MOVING THROUGH THE NORTHEAST AND SOUTHEASTERN CANADA PUSHES A SURFACE LOW OFF THE NEW ENGLAND COAST. AS THIS LOW MOVES EAST IT HELPS PULL THE FRONT STALLED JUST OFF THE COAST FARTHER EAST. SOME DIFFERENCES BETWEEN THE GFS/ECMWF SOLUTIONS WITH THE STALLED FRONT...THE GFS IS ADVERTISING A SLOWER SOLUTION WHICH HOLDS ONTO POP ALONG THE COAST THU AND THU NIGHT. INHERITED A SLIGHT CHANCE THU...WILL TRIM POP INLAND BUT HOLD ONTO SLIGHT CHANCE AT THE COAST. LACK OF ANY REAL COLD ADVECTION OR CLOUD COVER RESULTS IN HIGHS SEVERAL DEGREES ABOVE CLIMO. LOW ALSO END UP ABOVE CLIMO...THOUGH ONLY BY A FEW DEGREES AS DRIER AIR...ESPECIALLY INLAND...AND LIGHT WINDS ALLOW FOR SOME RADIATIONAL COOLING. SURFACE HIGH PRESSURE AND MUCH DRIER AIR BUILDS OVER THE REGION FRI AND SAT. COMBINATION OF DEEP WEST TO NORTHWEST FLOW AND LOW LEVEL NORTHEAST FLOW WILL KEEP THE REGION DRY WITH DOWNSLOPE FLOW HELPING KEEP HIGHS SLIGHTLY ABOVE CLIMO. DRY AIR AND RADIATIONAL COOLING WILL RESULT IN LOWS VERY CLOSE TO CLIMO TO END THE PERIOD. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... AS OF 06Z...SURFACE COLD FRONT IS SINKING SOUTH ACROSS THE EASTERN CAROLINAS...RUNNING AT 06Z FROM ABOUT 20 MILES S OF ILM...TO 15 MILES NW OF MYR...TO 15 MILES S OF FLO. THE BOUNDARY SHOULD CONTINUE TO SINK SOUTH THROUGH DAYBREAK. SHOWERS AND THUNDERSTORMS JUST NORTH OF THE FRONT ARE ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT WILL PUSH OFF THE NC COAST BY 09Z...TAKING PRECIP CHANCES WITH IT. THE FOCUS WILL TURN FROM CONVECTION TO LOW CEILINGS: LOW STRATUS IN THE 300-800 FT AGL RANGE WILL SLIP SOUTH BEHIND THE FRONT AND THREATEN ALL OF OUR AIRPORTS THIS MORNING. STRATUS AND ANY REDUCED VSBY IN BR WILL MIX OUT IN THE 13-14Z TIME FRAME...WITH VFR AND SCT/BKN MID AND HIGH CLOUDS THIS AFTERNOON. THE FRONT WILL BEGIN TO SWING BACK TO THE NORTH TONIGHT WITH A WINTER-LIKE RAIN SHIELD EXPECTED AS OVERRUNNING MOISTURE-LADEN SOUTH WINDS DEVELOP. EXTENDED OUTLOOK...UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONT COULD PRODUCE PERIODS OF IFR CONDITIONS ACROSS THE AREA THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SUNDAY...THE FRONT CONTINUES TO PRESS SOUTHWARD ALONG THE SC COAST AND SHOULD BE MOVING INTO GEORGETOWN SHORTLY. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 330 AM FOLLOWS... A COLD FRONT HAS PUSHED SOUTH THROUGH MYRTLE BEACH AND SHOULD STALL OUT LATER TODAY JUST SOUTH OF GEORGETOWN. THERE IS NOT A STRONG SURGE OF NORTH WINDS BEHIND THIS FRONT...AND WIND SPEEDS 10 KT OR LESS ARE EXPECTED TO PREDOMINATE. WAVES OF SHOWERS AND THUNDERSTORMS NORTH OF THE SURFACE FRONT ARE BEING PRODUCED BY AN UPPER LEVEL DISTURBANCE MOVING OFF THE NC COAST AND SHOULD DIMINISH AROUND DAYBREAK...AFFECTING MAINLY THE CAPE FEAR AREA. FOR TONIGHT THE FRONT WILL BEGIN TO LIFT BACK TO THE NORTH IN RESPONSE TO DEVELOPING LOW PRESSURE ALONG THE CENTRAL GULF COAST. THE FRONT MAY REACH MYRTLE BEACH BY DAYBREAK MONDAY...WITH WINDS SOUTH OF THE FRONT SHIFTING TO THE SOUTH...WITH LIGHTER NORTHEAST TO EAST WINDS EXPECTED NORTH OF THE BOUNDARY. SEAS AT THE NEARSHORE AND OFFSHORE BUOYS ARE ONLY 2 FEET CURRENTLY...AND LITTLE CHANGE IS EXPECTED THROUGH TONIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...WARM FRONT WILL LIFT NORTH OF THE WATERS MON WITH SOUTHERLY FLOW DEVELOPING. RIGHT BEHIND THE FRONT WINDS WILL BE EAST-SOUTHEAST...BUT DURING THE AFTERNOON WINDS BECOME MORE SOUTHERLY. SLIGHT INCREASE IN GRADIENT WILL SEE WINDS INCREASE INTO THE 10 TO 15 KT RANGE ON MON. FURTHER TIGHTENING OF THE GRADIENT IS POSSIBLE MON NIGHT INTO TUE WHICH MAY RESULT IN A SOLID 15 KT TUE INTO TUE NIGHT. LATE IN THE PERIOD WEAK COLD FRONT MOVES OFF THE COAST. BEHIND THE FRONT WINDS BECOME WEST-SOUTHWEST AROUND 10 KT AS GRADIENT RELAXES AND COLD ADVECTION FAILS TO DEVELOP. SEAS START OUT 2 TO 3 FT BUT BUILD TO 3 TO 4 FT LATE MON NIGHT AND 3 TO 5 FT TUE INTO TUE NIGHT BEFORE SOUTHWEST FLOW AND REDUCTION IN SPEEDS RESULTS IN A SLIGHT DECREASE IN SEAS. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...FRONT STALLED ACROSS THE WATERS AND LACK OF ANY SIGNIFICANT GRADIENT WILL KEEP SPEEDS AROUND 10 KT OR LESS WED...WITH A SOUTHWESTERLY COMPONENT. WED NIGHT HIGH PRESSURE CENTERED TO THE WEST SLIDES NORTHEAST AS THE STALLED FRONT STARTS TO PUSH EAST. WINDS VEER TO NORTHWEST LATE WED NIGHT AND CONTINUE VEERING TO NORTHEAST THU AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. LIGHT AND CHANGEABLE WINDS DURING THE PERIOD WILL RESULT IN SEAS FALLING THROUGH THE PERIOD. 2 TO 4 FT WED DECREASING TO 2 TO 3 FT THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...III AVIATION...TRA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
709 AM EDT SUN SEP 30 2012 .SYNOPSIS... LOW PRESSURE OVER THE EAST COAST WILL MOVE SLOWLY NORTHEAST AND EXTEND A TROUGH BACK WEST OVER THE REGION THROUGH TONIGHT. HIGH PRESSURE WILL BUILD EAST ON MONDAY ACROSS THE AREA. LOW PRESSURE AND A RESULTING WARM FRONT WILL LIFT NORTH ACROSS THE REGION ON TUESDAY. THE LOW WILL REMAIN IN THE AREA THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO MAKE MINOR CHANGES TO THE SKY COVER AND POPS FOR THE MORNING. STILL SOME QUESTION HOW EXTENSIVE THE COVERAGE OF SHOWERS TODAY. THE CIRCULATION AROUND THE LOW WILL BE VERY CYCLONIC SO THAT SHOULD ENHANCE THE CLOUDS AND SHOWERS AND THUNDERSTORMS. THE UPPER LOW OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WILL MOVE SOUTHEAST TODAY. THE BIG QUESTION IS WHAT KIND OF POP IS NEEDED FOR NE OH AND NW PA AND HOW FAR WEST TO CARRY A THREAT. THE HRRR MODEL REALLY DECREASES THE THREAT BY DAYBREAK. WITH THE INSTABILITY SO STRONG THE LAKE AND 500 MB TEMPERATURE DIFFERENCE NEAR 43C FROM LAKE COUNTY EAST TODAY...WILL KEEP THE LIKELY POPS GOING THROUGH EARLY TO MID AFTERNOON AND THEN DECREASE THEM AS SUBSIDENCE OCCURS BEHIND THE VORT MAX. THE HRRR IS NOW KEEPING SHOWERS GOING LONGER INTO THE AFTERNOON WHICH SEEMS GOOD WITH SOME MUCH INSTABILITY. MOST MODELS AGREE WITH THIS. CONFIDENCE IS MODERATE. AS PER THE HRRR MODEL AND SOME SHOWERS ON LAKE HURON WILL HAVE A THREAT OF SHOWERS AS FAR WEST AS THE ISLANDS. USED A BLEND OF GUIDANCE FOR THE HIGHS...COOLER EAST BECAUSE OF THE CLOUDS AND SHOWERS AND WARMER WEST WITH SOME SUNSHINE THIS AFTERNOON. WILL MENTION OF THREAT OF SMALL HAIL IN EXTREME NE OH AND NW PA AND WATERSPOUTS OVER THE EAST END OF THE LAKE. THIS WILL BE IN GRIDS AND THE HWO. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE WILL BE BUILDING IN BUT WITH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE NEAR 13C SOME LAKE ENHANCED SHOWERS MAY OCCUR. THE BEST CHANCE WOULD BE NW PA WHERE THE MOISTURE IS A LITTLE BETTER...ESPECIALLY EARLY TONIGHT. ELSEWHERE SOME CIRRUS WILL BE MOVING IN FROM THE SOUTHWEST. THIS MAY HELP LIMIT ANY WIDESPREAD DENSE FOG FROM DEVELOPING...SO WILL NOT MENTION IT AT THIS TIME. WATCHING THE NEXT WEATHER MAKER FOR THE REGION FROM THE GULF OF MEXICO. THE 00Z ECMWF IS VERY QUICK WITH THIS SYSTEM...DIDN`T GO AS FAST AS THE ECMWF BUT DID SPEED THE TIMING OF THE SHOWERS A LITTLE BIT. LIKELY LOOKS GOOD MONDAY NIGHT INTO TUESDAY AND THEN CHANCE AFTER THAT AS WE GET CLOSE TO THE WARM SECTOR. AT THIS TIME NO MENTION OF THUNDER BUT A THREAT WILL EVENTUALLY HAVE TO BE MENTIONED. NOT CONFIDENT ENOUGH TO FORECAST IT AT THIS TIME. USED A BLEND OF THE GUIDANCE BUT WITH PLENTY OF CLOUDS AND SHOWERS AROUND WENT COOLER FOR THE HIGHS AND WARMER FOR THE LOWS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE PERIOD WILL START OUT DRY ON THURSDAY AS THE AREA WILL BE BETWEEN WEATHER SYSTEMS. MODELS CONTINUE TO MOVE NEXT COLD FRONT ACROSS THE AREA ON FRIDAY. ECMWF CONTINUES TO BE THE FASTER OF THE 2 MODELS. ECMWF HAS THE FRONT JUST EXITING THE AREA BY 12Z FRIDAY WHILE THE GFS JUST HAS THE FRONT INTO NW OH. CONTINUED TO USE THE SLOWER GFS FOR FORECAST. MODELS DIFFER SIGNIFICANTLY ON SATURDAY. ECMWF HAS ANOTHER STRONG COLD FRONT PUSHING ACROSS THE AREA ON SATURDAY. GFS ON OTHER HAND HAS LARGE LOW SETTING UP OVER JAMES BAY WITH A SERIES OF TROUGHS SWINGING ACROSS EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE GFS SOLUTION. LEFT CHANCE POPS SNOWBELT EAST OF CLEVELAND FOR SATURDAY WITH TROUGH AND IN ADDITION 850 MB TEMPS DIP TO MINUS 4C SETTING UP POTENTIAL FOR LAKE EFFECT SHOWERS. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... UPPER LEVEL SHORT WAVE NOW OVER SOUTHERN LAKE HURON WILL SWING ACROSS THE AREA THIS MORNING. THIS WILL PRODUCE SCATTERED SHOWERS AND ISOLATED TSRA FROM CLE EAST THIS MORNING. DO NOT THINK IT WILL BE ANY WORSE THAN MVFR CONDITIONS IN THE HEAVIER SHOWERS. SKIES WILL BEGIN TO SCATTER OUT FROM THE NORTH BY MID AFTERNOON AS THE VORT MAX SWINGS SOUTH OF THE AREA. .OUTLOOK...NON-VFR CONDITIONS PROBABLE TUESDAY INTO WEDNESDAY IN SHRA. && .MARINE... FLOW WILL BECOME NORTHEAST TODAY BUT CONDITIONS WILL STAY BELOW SMALL CRAFT ADVISORY CRITERIA. NE FLOW WILL CONTINUE ON SUNDAY AND THEN BECOME NORTHERLY ON SUNDAY NIGHT AS HIGH PRESSURE BRIEFLY RETURNS. LOCAL SCHEMES SHOWING A GOOD CHANCE FOR WATERSPOUTS ON SUNDAY. BEST CHANCES FOR THIS WILL BE TO THE EAST OF CLEVELAND AND ANYWHERE A DECENT SHOWER DEVELOPS. LOW PRESSURE STILL FORECAST TO MOVE ACROSS THE OHIO VALLEY ON TUESDAY...AND ACROSS LAKE ERIE TUESDAY NIGHT. MODELS STILL NOT IN GOOD AGREEMENT ON EXACT TRACK AND TIMING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
659 AM EDT SUN SEP 30 2012 .SYNOPSIS... LOW PRESSURE OVER THE EAST COAST WILL MOVE SLOWLY NORTHEAST AND EXTEND A TROUGH BACK WEST OVER THE REGION THROUGH TONIGHT. HIGH PRESSURE WILL BUILD EAST ON MONDAY ACROSS THE AREA. LOW PRESSURE AND A RESULTING WARM FRONT WILL LIFT NORTH ACROSS THE REGION ON TUESDAY. THE LOW WILL REMAIN IN THE AREA THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO MAKE MINOR CHANGES TO THE SKY COVER AND POPS FOR THE MORNING. STILL SOME QUESTION HOW EXTENSIVE THE COVERAGE OF SHOWERS TODAY. THE CIRCULATION AROUND THE LOW WILL BE VERY CYCLONIC SO THAT SHOULD ENHANCE THE CLOUDS AND SHOWERS AND THUNDERSTORMS. THE UPPER LOW OVER THE EASTERN GREAT LAKES EARLY THIS MORNING WILL MOVE SOUTHEAST TODAY. THE BIG QUESTION IS WHAT KIND OF POP IS NEEDED FOR NE OH AND NW PA AND HOW FAR WEST TO CARRY A THREAT. THE HRRR MODEL REALLY DECREASES THE THREAT BY DAYBREAK. WITH THE INSTABILITY SO STRONG THE LAKE AND 500 MB TEMPERATURE DIFFERENCE NEAR 43C FROM LAKE COUNTY EAST TODAY...WILL KEEP THE LIKELY POPS GOING THROUGH EARLY TO MID AFTERNOON AND THEN DECREASE THEM AS SUBSIDENCE OCCURS BEHIND THE VORT MAX. THE HRRR IS NOW KEEPING SHOWERS GOING LONGER INTO THE AFTERNOON WHICH SEEMS GOOD WITH SOME MUCH INSTABILITY. MOST MODELS AGREE WITH THIS. CONFIDENCE IS MODERATE. AS PER THE HRRR MODEL AND SOME SHOWERS ON LAKE HURON WILL HAVE A THREAT OF SHOWERS AS FAR WEST AS THE ISLANDS. USED A BLEND OF GUIDANCE FOR THE HIGHS...COOLER EAST BECAUSE OF THE CLOUDS AND SHOWERS AND WARMER WEST WITH SOME SUNSHINE THIS AFTERNOON. WILL MENTION OF THREAT OF SMALL HAIL IN EXTREME NE OH AND NW PA AND WATERSPOUTS OVER THE EAST END OF THE LAKE. THIS WILL BE IN GRIDS AND THE HWO. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE WILL BE BUILDING IN BUT WITH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE NEAR 13C SOME LAKE ENHANCED SHOWERS MAY OCCUR. THE BEST CHANCE WOULD BE NW PA WHERE THE MOISTURE IS A LITTLE BETTER...ESPECIALLY EARLY TONIGHT. ELSEWHERE SOME CIRRUS WILL BE MOVING IN FROM THE SOUTHWEST. THIS MAY HELP LIMIT ANY WIDESPREAD DENSE FOG FROM DEVELOPING...SO WILL NOT MENTION IT AT THIS TIME. WATCHING THE NEXT WEATHER MAKER FOR THE REGION FROM THE GULF OF MEXICO. THE 00Z ECMWF IS VERY QUICK WITH THIS SYSTEM...DIDN`T GO AS FAST AS THE ECMWF BUT DID SPEED THE TIMING OF THE SHOWERS A LITTLE BIT. LIKELY LOOKS GOOD MONDAY NIGHT INTO TUESDAY AND THEN CHANCE AFTER THAT AS WE GET CLOSE TO THE WARM SECTOR. AT THIS TIME NO MENTION OF THUNDER BUT A THREAT WILL EVENTUALLY HAVE TO BE MENTIONED. NOT CONFIDENT ENOUGH TO FORECAST IT AT THIS TIME. USED A BLEND OF THE GUIDANCE BUT WITH PLENTY OF CLOUDS AND SHOWERS AROUND WENT COOLER FOR THE HIGHS AND WARMER FOR THE LOWS. && .LONG TERM /THURSDAY THROUGH SATURDAY/... THE PERIOD WILL START OUT DRY ON THURSDAY AS THE AREA WILL BE BETWEEN WEATHER SYSTEMS. MODELS CONTINUE TO MOVE NEXT COLD FRONT ACROSS THE AREA ON FRIDAY. ECMWF CONTINUES TO BE THE FASTER OF THE 2 MODELS. ECMWF HAS THE FRONT JUST EXITING THE AREA BY 12Z FRIDAY WHILE THE GFS JUST HAS THE FRONT INTO NW OH. CONTINUED TO USE THE SLOWER GFS FOR FORECAST. MODELS DIFFER SIGNIFICANTLY ON SATURDAY. ECMWF HAS ANOTHER STRONG COLD FRONT PUSHING ACROSS THE AREA ON SATURDAY. GFS ON OTHER HAND HAS LARGE LOW SETTING UP OVER JAMES BAY WITH A SERIES OF TROUGHS SWINGING ACROSS EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE GFS SOLUTION. LEFT CHANCE POPS SNOWBELT EAST OF CLEVELAND FOR SATURDAY WITH TROUGH AND IN ADDITION 850 MB TEMPS DIP TO MINUS 4C SETTING UP POTENTIAL FOR LAKE EFFECT SHOWERS. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... SURFACE TROUGH SWINGING ACROSS EASTERN PORTION OF FORECAST AREA NOW KICKING OFF A FEW SHOWERS. WILL BE A BRIEF RESPITE...THEN UPPER LEVEL VORTICITY MAX NOW OVER LAKE HURON WILL SWING ACROSS THE AREA SHORTLY AFTER SUNRISE. THIS WILL ALSO KICK OFF A FEW SHOWERS...BUT DO NOT THINK IT WILL BE ANY WORSE THAN MVFR CONDITIONS IN THE HEAVIER SHOWERS. AGAIN MOST SHOWERS WILL BE FROM CLEVELAND EAST. SKIES WILL BEGIN TO SCATTER OUT FROM THE NORTH BY MID AFTERNOON AS THE VORT MAX SWINGS SOUTH OF THE AREA. .OUTLOOK...NON-VFR CONDITIONS PROBABLE TUESDAY INTO WEDNESDAY IN SHRA. && .MARINE... FLOW WILL BECOME NORTHEAST TODAY BUT CONDITIONS WILL STAY BELOW SMALL CRAFT ADVISORY CRITERIA. NE FLOW WILL CONTINUE ON SUNDAY AND THEN BECOME NORTHERLY ON SUNDAY NIGHT AS HIGH PRESSURE BRIEFLY RETURNS. LOCAL SCHEMES SHOWING A GOOD CHANCE FOR WATERSPOUTS ON SUNDAY. BEST CHANCES FOR THIS WILL BE TO THE EAST OF CLEVELAND AND ANYWHERE A DECENT SHOWER DEVELOPS. LOW PRESSURE STILL FORECAST TO MOVE ACROSS THE OHIO VALLEY ON TUESDAY...AND ACROSS LAKE ERIE TUESDAY NIGHT. MODELS STILL NOT IN GOOD AGREEMENT ON EXACT TRACK AND TIMING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 AM EDT SUN SEP 30 2012 .SYNOPSIS... A DEEP UPPER LOW PRESSURE SYSTEM WILL ROTATE THROUGH NORTHERN PENNSYLVANIA THIS AFTERNOON...THEN QUICKLY LIFT NORTHWARD AND MOVE AWAY FROM THE AREA TONIGHT. HIGH PRESSURE WILL BRIEFLY VISIT THE REGION ON MONDAY. WET WEATHER WILL RETURN TO THE KEYSTONE STATE MONDAY NIGHT THROUGH TUESDAY AS A WAVE OF LOW PRESSURE EJECTS NORTHWARD FROM THE CENTRAL GULF STATES. && .NEAR TERM /THROUGH TONIGHT/... REGIONAL RADAR DOES NOT SHOW MUCH ON THE SCOPE AT OF 15Z...EXCEPT FOR AN AREA OF SHOWERS OVR THE LAUREL HIGHLANDS/SW PA. STILL EXPECTING NMRS INSTABILITY SHOWERS TO DEVELOP BY THE EARLY AFTN WITH THE HEATING OF THE DAY /ALBEIT MODEST/...UNDER H5-H7 COLD POOL OF -15C. THIS WILL SUPPORT MID-LVL LAPSE RATES AROUND 7 C/KM WHICH IS A VERY STRONG SIGNAL FOR INSTABILITY SHOWERS. SMALL HAIL WILL BE POSSIBLE IN THE MORE ROBUST...LOW- TOPPED CONVECTIVE CELLS. THE LATEST HRRR SHOWS THE GREATEST CONCENTRATION OF SHOWER ACTIVITY INVOF I-80/N-CENTRAL MTNS WHERE HIGHEST POPS HAVE PAINTED IN THE GRIDS. ANY PEAKS OF SUN THIS MORNING WILL BE REPLACED BY SELF-DESTRUCT CUMULUS/STRATOCU WITH BKN SKIES ANTICIPATED ACRS MUCH OF THE CWA BY LATE MORNING. HIGHS WILL ONLY MAKE IT INTO THE 50S AND 60S...WHICH WILL BE AS MUCH AS 10 DEG BELOW NORMAL IN SOME AREAS. EXPECT INSTABILITY SHOWERS/ISOLD TSRA TO QUICKLY WEAKEN AND DISSIPATE WITH THE LOSS OF HEATING INTO TONIGHT. THERE SHOULD ALSO BE A GRADUAL DECREASE IN CLOUDS AS HIGH PRES BUILDS IN FROM THE UPPER OH VLY. SOME LLVL MSTR MAY GET TRAPPED BLW INVERSION AND RESULT IN LOW STRATUS/FOG INTO EARLY MONDAY MORNING...ESP ACRS THE ALLEGHENIES GIVEN WEAK WNW UPSLOPE. OVERNIGHT LOWS WILL BE NEAR SEASONAL NORMALS. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... AFTER SOME PATCHY EARLY MORNING FOG/LOW CLOUDS...SFC RIDGE WILL BISECT THE STATE IN BETWEEN DEPARTING NRN STREAM UPPER TROUGH LIFTING NWD ACRS NRN NEW ENGLAND AND DEVELOPING SRN STREAM WAVE OF LOW PRES OVR MS/AL. EXPECT AN INCREASE IN MID-HIGH CLOUDS IN ADVANCE OF THE SRN SYSTEM LATE IN THE DAY...AS IT MOVES NWD INTO THE TN VLY BY 00Z TUE. HIGHS WILL BE QUITE PLEASANT IN THE 60S TO LOWER 70S NORTH TO SOUTH. MDLS IN DECENT AGREEMENT IN MOVG THE SFC WAVE INTO TN/KY BY THE END OF THE PERIOD. ANOMALOUS SLY LLJ WILL SUPPORT ROBUST NWD MSTR FLUX INTO THE AREA MON NGT...WITH PWATS SURGING TO +2-3SD BY 12Z TUE. ANOTHER INTERESTING FEATURE IS PERHAPS A DUEL/INC MSTR FEED FM THE GOMEX AND ATM RIVER EMANATING FM THE BAHAMAS. THERE ARE STILL SOME DETAIL DIFFS WITH THE SYS AND WILL REFINE DY2 FCST BASED ON THE LATER ARRIVING 30/12Z GUID. FOR NOW...FELT THAT AN INCREASE IN POPS IS JUSTIFIED GIVEN THE STG WAA/ISENT LIFT AND MSTR TRANSPORT INTO THE REGION. && .LONG TERM /TUESDAY THROUGH SATURDAY/... THE LARGE SCALE PATTERN QUICKLY RELOADS INTO A HIGH AMPLITUDE TROF OVER THE EASTERN HALF OF THE US. THE DETAILS DIFFER BETWEEN THE VARIOUS MODELS...BUT IT LOOKS LIKE THE CONSENSUS IS FOR A LOW TO MOVE UP TOWARD THE CENTRAL GR LAKES...WITH THE OCCLUDED FRONT EVENTUALLY SWINGING THRU THE REGION SOME TIME TUES NIGHT OR WED. THE SHORT RANGE GUIDANCE SHOWS ERODING STABILITY AND SUGGESTS THE POSSIBILITY OF SOME CONVECTION AS THE FRONT GETS CLOSER TUES. 03Z SREF STILL SHOWS AS MUCH AS A 30-50 PROB OF 24 HOUR RAINFALLS OF AN INCH OR MORE OVER WEST-CENTRAL PA...MAINLY FROM TUESDAY INTO WED. THIS ISN`T MUCH DIFFERENT THAN THE 21Z RUN. THE GEFS IS NOT NEARLY AS AGGRESSIVE AND HAS SHIFTED ITS LOWER PROBABILITY OF ONE INCH RAINS MAINLY OFF TO OUR SE...WHICH MATCHES BETTER TO WHERE THE OPERATIONAL MODEL SUGGESTS THE POSSIBILITY OF A COASTAL SECONDARY WAVE TO FORM. AT THIS STAGE THE DIFFERENCES IN GUIDANCE MUDDY THE DETAILS...BUT WHAT LOOKS ALMOST ASSURED IS THAT WE WILL SEE A WIDESPREAD LIGHT TO MODERATE RAIN...AND A MINIMAL FLOOD THREAT AT THIS TIME. AFTER THE SFC LOW/FRONT MOVES THROUGH...THE UPPER LOW WILL THEN PUSH THROUGH WED/WED NIGHT KEEPING THE MENTION OF SHOWERS IN THE FORECAST. BY THURSDAY WE SHOULD SEE ENOUGH RIDGING FROM THE WEST TO DRY OUT...AT LEAST TEMPORARILY. THE GEFS/GFS AND CANADIAN MODELS SHOW AN APPROACHING ALBEIT FADING FRONT BY FRIDAY WITH THE PARENT UPPER SHORTWAVE WANTING TO SHEAR OUT WELL NORTH AND WEST OF HERE. THE ECMWF AT THIS POINT IS AN OUTLIER...HANGING MORE UPPER ENERGY BACK ITO THE NORTHERN ROCKIES...RESULTING IN A BROAD WSW FLOW EVENTUALLY ESTABLISHING OVER THE GR LAKES AND NERN US. THIS RESULTS IN THE MODEL DEVELOPING A SLOW MOVING WAVY ANA-FRONT THAT APPROACHES THE AREA FOR THE WEEKEND. DEPENDING ON TIMING...IT COULD EITHER BE MILD AND DRY...OR CHILLY AND RAINY. AS A RESULT...HAVE CHOSEN TO NOT TOUCH THE EXTENDED PORTION OF THE FORECAST WHERE WE NOW HAVE SMALL CHANCES FOR RAIN...WHICH WOULD BETTER FIT A WASHING FRONTAL PASSAGE CONCEPTUAL MODEL. IT DOES LOOK LIKE ONCE THE RAIN MOVES THROUGH...WE SHOULD ENJOY SEVERAL DAYS OF ABOVE NORMAL WARMTH STARTING ABOUT WEDNESDAY. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... 30/15Z...COLD AIR ALOFT AND DAYTIME HEATING WILL RESULT IN BKN CU/SC FIELD ACRS CENTRAL PA TERMINALS BY THE EARLY AFTN. CLOUDS BASES WILL BE IN THE LOW END VFR RANGE BTWN 3.5-6KFT AGL. IN ADDITION...EXPECT SCT TO NMRS INSTABILITY SHOWERS TO DEVELOP UNDER THE COLD POOL ALOFT ASSOC WITH A CLOSED UPPER LEVEL LOW PIVOTING OVR PA/NY THIS AFTN. THERE MAY ALSO BE AN ISOLD TSRA BUT WILL CVRG/CONFIDENCE TOO LOW FOR MENTION IN TAFS ATTM. WITH THE LOSS OF DAYTIME HEATING...EXPECT SHOWERS TO QUICKLY DISSIPATE AFT 00Z. SFC HIGH PRES WILL SLIDE INTO THE REGION FROM THE UPPER OH VLY OVERNIGHT. SOME RESIDUAL LLVL MSTR MAY GET TRAPPED UNDER INVERSION AND RESULT IN LOW CIGS/FOG OVERNIGHT...ESP OVR THE WRN MTNS GIVEN WEAK UPSLOPE FLOW. OUTLOOK... MON...AM LOW CIGS/FOG POSSIBLE ACROSS THE W MTNS...BCMG VFR. TUE...RAIN/LOW CIGS LIKELY...ESP OVR THE CENTRAL MTNS. WED...RAIN/LOW CIGS POSSIBLE. THU...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...LA CORTE/STEINBUGL LONG TERM...LA CORTE AVIATION...MARTIN/STEINBUGL
AREA FORECAST DISCUSSION
NWS NEW YORK NY
133 PM EDT SUN SEP 30 2012 .SYNOPSIS... A BROAD UPPER LEVEL STORM SYSTEM IMPACTS THE NORTHEAST INTO MONDAY. WEAK HIGH PRESSURE BUILDS IN MONDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM...WHICH WILL PASS THROUGH MID WEEK. HIGH PRESSURE BRIEFLY BUILDS IN THE END OF THE WEEK BEFORE THE NEXT FRONT APPROACHES FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST WATER VAPOR AND RUC ANALYSIS SHOW CUTOFF LOW ALOFT CENTERED NEAR THE CENTRAL NY/PA BORDER...WITH A 38 UNIT 500 HPA VORTICITY MAXIMUM ALONG THE S SHORE OF LONG ISLAND LIFTING NE. AHEAD OF THIS VORTICITY MAXIMUM - STRONG POSITIVE VORTICITY ADVECTION - THERE ARE ISOLD- SCT SHRA...AND BEHIND IT - NEGATIVE VORTICITY ADVECTION - DRY CONDITIONS WITH MAINLY FEW-SCT CLOUD COVERAGE. THE NEXT VORTICITY MAXIMUM APPROACHES WESTERN ZONES BY LATE AFTERNOON...SO INTRODUCE ISOLD-SCT SHRA THERE. A BLEND OF NAM/SREF/HRRR POPS REFLECTS PRECIPITATION TREND FAIRLY WELL...THOUGH MIGHT BE UNDER DOING AREA TO BE MAINLY DRY THIS AFTERNOON. CMC-REG SKY PRODUCT HAS HANDLED SKY COVER THIS MORNING WELL...SO HAVE USED IT TO UPDATE SKY GRIDS. NO LIGHTNING HAS BEEN OBSERVED OVER THE NE UNITED STATES OVER THE PAST SEVERAL HOURS...AND GIVEN THIS TREND...HAVE REMOVED THE MENTION OF THUNDER FROM THE FORECAST FOR THIS AFTERNOON. 12Z KOKX AND KALY SOUNDINGS SUGGEST HIGHS RANGING FROM THE LOWER 60S ACROSS THE NORTHERN INTERIOR TO THE MID-UPPER 60S NEAR THE COAST. THIS IS CONSISTENT WITH A BLEND OF 12Z MET/MAV/NAM 2-METER TEMPERATURES. HOURLY AND HIGH TEMPERATURE GRIDS ADJUSTED ACCORDINGLY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... DRYING CONDITIONS THIS PERIOD AS THE UPPER LEVEL LOW FINALLY PUSHES OFF TO THE NORTHEAST...ALLOWING FOR RIDGING TO BUILD IN ON MONDAY. THE SURFACE LOW MOVES OFF TO THE NORTH AS WELL...DRAGGING A TROUGH THROUGH THE CWA...RESULTING IN A MORE WESTERLY FLOW TO THE WEST...AND A SOUTHWESTERLY FLOW OVER THE EAST. A TIGHTENING PRESSURE GRADIENT BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FROM THE SOUTH WILL INCREASE WINDS LATE SUNDAY NIGHT INTO MONDAY...WITH GUSTS BETWEEN 15 AND 20 MPH POSSIBLE. SOUNDINGS INDICATE DRYING AT ALL LEVELS AS THE LOW MOVES AWAY AND COOLER AIR IS USHERED IN ON THE BACKSIDE OF THE LOW...CREATING PLENTY OF SUBSIDENCE FOR MONDAY. OTHER THAN A FEW LINGERING SHOWERS THIS EVENING...SHOULD HAVE A DRY FORECAST UNTIL MONDAY NIGHT WHEN THE FLOW RETURNS TO THE SOUTH AND THE MOISTURE FIELD BEGINS INCREASING. GFS THE WARMEST WITH TEMPS WITH IT PUSHING THE LOW OUT THE QUICKEST. SIDED WITH THE SLIGHTLY SLOWER NAM GUIDANCE FOR TEMPS...WHICH KEEPS TEMPS NEAR NORMAL. IF SKIES CLEAR QUICKER THAN FORECASTED...COULD SEE TEMPS DROP ANOTHER COUPLE OF DEGREES...ESP INLAND. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... OVERALL...UNSETTLED WEATHER STILL FORECASTED FOR MID WEEK...WITH A BREAK IN THE PRECIPITATION POSSIBLE THURS/FRI. WHILE MODEL DISCREPANCIES ARE STILL IN PLACE...THERE IS SOME BETTER ALIGNMENT WITH THE 00Z RUNS...ALLOWING FOR SLIGHTLY HIGHER CONFIDENCE ON THE FORECAST. WEAK HIGH PRESSURE AT THE SURFACE BEGINS TO RETREAT TUESDAY AS A WARM FRONT ASSOCIATED WITH A SURFACE LOW OVER THE OHIO RIVER VALLEY APPROACHES AND MOVES THROUGH THE NORTHEAST. DESPITE DIFFERENCES IN THE EXACT TIMING...GENERAL MODEL CONSENSUS IS A TAD SLOWER WITH THE PROGRESSION OF THE LOW AND ITS ASSOCIATED FRONTS. 00Z NAM REMAINS THE MAIN OUTLIER WITH TIMING...REALLY SLOWING EVERYTHING DOWN TILL WED. HOWEVER...DECIDED TO SIDE WITH THE MORE CONSISTENT AND PROGRESSIVE PATHS...BRINGING THE PRECIPITATION IN BY TUES NIGHT. KEPT CHANCE POPS IN FOR TUES MORNING WITH INCREASING WAA/MOISTURE FIELD...THEN INCREASED POPS THROUGHOUT THE DAY INTO TUES NIGHT ALONG THE ISENTROPIC LIFT. ALSO TIMED PRECIPITATION OUT TO CORRESPOND WITH PASSING SHORTWAVES ALONG THE NORTHERN FRINGE OF THE UPPER LEVEL RIDGE. CHANCE OF PRECIPITATION REMAINS MENTIONED THROUGH WED ALONG THE PASSAGE OF THE COLD FRONT/SURFACE LOW. HOWEVER...WITH RIDGING IN PLACE ALOFT...EXPECT THINGS TO DRY OUT RATHER QUICKLY ONCE THE FRONT PASSES. SURFACE HIGH PRESSURE BUILDS IN FROM THE SOUTH THURS INTO FRI...WHICH SHOULD KEEP THE DRY WEATHER IN PLACE. ANOTHER STORM SYSTEM IS EXPECTED TO IMPACT THE AREA THIS WEEKEND...BUT TIMING IS STILL UNCERTAIN AT THIS TIME. THUS...CONTINUED PREVIOUS FORECAST FOR THE END OF THE WEEK DUE TO THESE UNCERTAINTIES. WAA AHEAD OF THE COLD FRONT MID WEEK WILL PUSH TEMPS BACK TO ABOVE NORMAL TUES THROUGH THURS...WITH CLOUDY CONDITIONS AND RAIN MODERATING TEMPS. SLIGHT COOLING SETTLES IN FRI...BUT THE NEXT BURST OF COOLER AIR LOOKS TO BE AFTER THE FRONT THIS WEEKEND. GENERALLY WENT WITH A BLEND OF HPC/MOS GUIDANCE FOR TEMPS AND DEW POINTS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... LOW PRES OVER THE GULF OF ME WILL CONTINUE TO TRACK N TNGT. MAINLY VFR THRU THE TAF PERIOD. MVFR AT KGON WILL IMPROVE THRU THE REMAINDER OF THE AFTN. ELSEWHERE...ISOLD-SCT SHRA WILL DEVELOP ACROSS NJ AND UPSTATE NY. VCSH HAS BEEN INCLUDED FOR KTEB AND KEWR. POTENTIAL FOR THESE SHRA TO GET INTO KLGA AND KJFK. THERE COULD BE AN ISOLD TSTM EMBEDDED IN THE DEVELOPING SHRA...WITH SMALL HAIL POSSIBLE. SHRA DISSIPATE THIS EVE...WITH DRY CONDITIONS THEREAFTER THRU THE TAF PERIOD. VRB WIND FLOW WILL BACK TO THE W. SOME GUSTS AROUND 18KT POSSIBLE. FLOW DECREASES TNGT...THEN WINDS INCREASE AGAIN MON MRNG. W DIRECTION IS EXPECTED TO REMAIN NEARLY THE SAME THRU THE TAF PERIOD AFT THE SHIFT OCCURS. OUTLOOK FOR 18Z MONDAY-FRIDAY... .MONDAY AFTN-MONDAY NIGHT...VFR. GUSTS ARE POSSIBLE DURING THE DAY. .TUESDAY-WEDNESDAY...MVFR OR LOWER LIKELY. PERIODS OF -RA POSSIBLE. .THURSDAY...MRNG MVFR OR LOWER POSSIBLE. IMPROVEMENT TO VFR BY AFTN. .FRIDAY...VFR. && .MARINE... MINOR CHANGES MADE IN THE GRIDS TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. SUB-SCA CONDITIONS TODAY WITH A NORTHERLY TO WESTERLY FLOW BETWEEN 5 AND 10 KTS. AS THE LOW DEPARTS TOMORROW AND THE HIGH BUILDS IN...TIGHTENING PRESSURE GRADIENT WILL INCREASE BOTH WINDS AND SEAS...WITH POSSIBLE GUSTS UP TO 25 KTS. THE PERSISTENT FLOW COULD INCREASE SEAS TO 5 FT ON THE OCEAN WATERS. WINDS AND SEAS DIMINISH BY TUESDAY AND SHOULD REMAIN SUB SCA FOR THE REMAINDER OF THE FORECAST. OCCASIONAL HIGHER GUSTS POSSIBLE WITH THE PASSAGE OF THE FRONT ON WED. && .HYDROLOGY... SIGNIFICANT PRECIPITATION IS NOT EXPECTED THROUGH SUNDAY NIGHT. A PROLONGED PERIOD OF STRATIFORM RAIN IS POSSIBLE FROM LATE MONDAY NIGHT INTO WEDNESDAY. SINCE THIS WILL BE A LONG DURATION EVENT AND HEAVY RAIN IS NOT EXPECTED AT THIS TIME...FLOODING DOES NOT APPEAR TO BE A CONCERN. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...SEARS NEAR TERM...MALOIT SHORT TERM...SEARS LONG TERM...SEARS AVIATION...JMC MARINE...MALOIT/SEARS HYDROLOGY...SEARS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1224 PM EDT SUN SEP 30 2012 .SYNOPSIS... A BROAD UPPER LEVEL STORM SYSTEM IMPACTS THE NORTHEAST INTO MONDAY. WEAK HIGH PRESSURE BUILDS IN MONDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM...WHICH WILL PASS THROUGH MID WEEK. HIGH PRESSURE BRIEFLY BUILDS IN THE END OF THE WEEK BEFORE THE NEXT FRONT APPROACHES FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST WATER VAPOR AND RUC ANALYSIS SHOW CUTOFF LOW ALOFT CENTERED NEAR THE CENTRAL NY/PA BORDER...WITH A 38 UNIT 500 HPA VORTICITY MAXIMUM ALONG THE S SHORE OF LONG ISLAND LIFTING NE. AHEAD OF THIS VORTICITY MAXIMUM - STRONG POSITIVE VORTICITY ADVECTION - THERE ARE ISOLD- SCT SHRA...AND BEHIND IT - NEGATIVE VORTICITY ADVECTION - DRY CONDITIONS WITH MAINLY FEW-SCT CLOUD COVERAGE. THE NEXT VORTICITY MAXIMUM APPROACHES WESTERN ZONES BY LATE AFTERNOON...SO INTRODUCE ISOLD-SCT SHRA THERE. A BLEND OF NAM/SREF/HRRR POPS REFLECTS PRECIPITATION TREND FAIRLY WELL...THOUGH MIGHT BE UNDER DOING AREA TO BE MAINLY DRY THIS AFTERNOON. CMC-REG SKY PRODUCT HAS HANDLED SKY COVER THIS MORNING WELL...SO HAVE USED IT TO UPDATE SKY GRIDS. NO LIGHTNING HAS BEEN OBSERVED OVER THE NE UNITED STATES OVER THE PAST SEVERAL HOURS...AND GIVEN THIS TREND...HAVE REMOVED THE MENTION OF THUNDER FROM THE FORECAST FOR THIS AFTERNOON. 12Z KOKX AND KALY SOUNDINGS SUGGEST HIGHS RANGING FROM THE LOWER 60S ACROSS THE NORTHERN INTERIOR TO THE MID-UPPER 60S NEAR THE COAST. THIS IS CONSISTENT WITH A BLEND OF 12Z MET/MAV/NAM 2-METER TEMPERATURES. HOURLY AND HIGH TEMPERATURE GRIDS ADJUSTED ACCORDINGLY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... DRYING CONDITIONS THIS PERIOD AS THE UPPER LEVEL LOW FINALLY PUSHES OFF TO THE NORTHEAST...ALLOWING FOR RIDGING TO BUILD IN ON MONDAY. THE SURFACE LOW MOVES OFF TO THE NORTH AS WELL...DRAGGING A TROUGH THROUGH THE CWA...RESULTING IN A MORE WESTERLY FLOW TO THE WEST...AND A SOUTHWESTERLY FLOW OVER THE EAST. A TIGHTENING PRESSURE GRADIENT BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FROM THE SOUTH WILL INCREASE WINDS LATE SUNDAY NIGHT INTO MONDAY...WITH GUSTS BETWEEN 15 AND 20 MPH POSSIBLE. SOUNDINGS INDICATE DRYING AT ALL LEVELS AS THE LOW MOVES AWAY AND COOLER AIR IS USHERED IN ON THE BACKSIDE OF THE LOW...CREATING PLENTY OF SUBSIDENCE FOR MONDAY. OTHER THAN A FEW LINGERING SHOWERS THIS EVENING...SHOULD HAVE A DRY FORECAST UNTIL MONDAY NIGHT WHEN THE FLOW RETURNS TO THE SOUTH AND THE MOISTURE FIELD BEGINS INCREASING. GFS THE WARMEST WITH TEMPS WITH IT PUSHING THE LOW OUT THE QUICKEST. SIDED WITH THE SLIGHTLY SLOWER NAM GUIDANCE FOR TEMPS...WHICH KEEPS TEMPS NEAR NORMAL. IF SKIES CLEAR QUICKER THAN FORECASTED...COULD SEE TEMPS DROP ANOTHER COUPLE OF DEGREES...ESP INLAND. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... OVERALL...UNSETTLED WEATHER STILL FORECASTED FOR MID WEEK...WITH A BREAK IN THE PRECIPITATION POSSIBLE THURS/FRI. WHILE MODEL DISCREPANCIES ARE STILL IN PLACE...THERE IS SOME BETTER ALIGNMENT WITH THE 00Z RUNS...ALLOWING FOR SLIGHTLY HIGHER CONFIDENCE ON THE FORECAST. WEAK HIGH PRESSURE AT THE SURFACE BEGINS TO RETREAT TUESDAY AS A WARM FRONT ASSOCIATED WITH A SURFACE LOW OVER THE OHIO RIVER VALLEY APPROACHES AND MOVES THROUGH THE NORTHEAST. DESPITE DIFFERENCES IN THE EXACT TIMING...GENERAL MODEL CONSENSUS IS A TAD SLOWER WITH THE PROGRESSION OF THE LOW AND ITS ASSOCIATED FRONTS. 00Z NAM REMAINS THE MAIN OUTLIER WITH TIMING...REALLY SLOWING EVERYTHING DOWN TILL WED. HOWEVER...DECIDED TO SIDE WITH THE MORE CONSISTENT AND PROGRESSIVE PATHS...BRINGING THE PRECIPITATION IN BY TUES NIGHT. KEPT CHANCE POPS IN FOR TUES MORNING WITH INCREASING WAA/MOISTURE FIELD...THEN INCREASED POPS THROUGHOUT THE DAY INTO TUES NIGHT ALONG THE ISENTROPIC LIFT. ALSO TIMED PRECIPITATION OUT TO CORRESPOND WITH PASSING SHORTWAVES ALONG THE NORTHERN FRINGE OF THE UPPER LEVEL RIDGE. CHANCE OF PRECIPITATION REMAINS MENTIONED THROUGH WED ALONG THE PASSAGE OF THE COLD FRONT/SURFACE LOW. HOWEVER...WITH RIDGING IN PLACE ALOFT...EXPECT THINGS TO DRY OUT RATHER QUICKLY ONCE THE FRONT PASSES. SURFACE HIGH PRESSURE BUILDS IN FROM THE SOUTH THURS INTO FRI...WHICH SHOULD KEEP THE DRY WEATHER IN PLACE. ANOTHER STORM SYSTEM IS EXPECTED TO IMPACT THE AREA THIS WEEKEND...BUT TIMING IS STILL UNCERTAIN AT THIS TIME. THUS...CONTINUED PREVIOUS FORECAST FOR THE END OF THE WEEK DUE TO THESE UNCERTAINTIES. WAA AHEAD OF THE COLD FRONT MID WEEK WILL PUSH TEMPS BACK TO ABOVE NORMAL TUES THROUGH THURS...WITH CLOUDY CONDITIONS AND RAIN MODERATING TEMPS. SLIGHT COOLING SETTLES IN FRI...BUT THE NEXT BURST OF COOLER AIR LOOKS TO BE AFTER THE FRONT THIS WEEKEND. GENERALLY WENT WITH A BLEND OF HPC/MOS GUIDANCE FOR TEMPS AND DEW POINTS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... LOW PRES E OF CAPE COD WILL CONTINUE TO TRACK N TODAY. LIGHT N/NW FLOW WILL BACK TO THE WNW THIS AFTN. SPEEDS WILL INCREASE INTO THE 10-15KT RANGE AFT 18Z. VFR IS OVERSPREADING THE REGION FROM THE SW. THIS TREND IS EXPECTED TO CONTINUE. CU IS EXPECTED TO BEGIN TO DEVELOP IN THE 16-18Z PERIOD. ISOLD-SCT SHRA ARE POSSIBLE...HOWEVER THE BULK OF THIS ACTIVITY IS PROGGED TO BE N OF THE CITY TERMINALS. ANY SHRA DISSIPATE BY 23-00Z. TONIGHT...WINDS REMAIN FROM THE WEST AROUND 10 KT OR LESS WITH VFR CONDITIONS. OUTLOOK FOR 12Z MONDAY-THURSDAY... .MONDAY-MONDAY NIGHT...VFR. GUSTS ARE POSSIBLE DURING THE DAY MONDAY. .TUESDAY-WEDNESDAY...MVFR OR LOWER CONDITIONS POSSIBLE IN SHRA. .WEDNESDAY NIGHT-THURSDAY...VFR. && .MARINE... MINOR CHANGES MADE IN THE GRIDS TO REFLECT THE LATEST TRENDS IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. SUB-SCA CONDITIONS TODAY WITH A NORTHERLY TO WESTERLY FLOW BETWEEN 5 AND 10 KTS. AS THE LOW DEPARTS TOMORROW AND THE HIGH BUILDS IN...TIGHTENING PRESSURE GRADIENT WILL INCREASE BOTH WINDS AND SEAS...WITH POSSIBLE GUSTS UP TO 25 KTS. THE PERSISTENT FLOW COULD INCREASE SEAS TO 5 FT ON THE OCEAN WATERS. WINDS AND SEAS DIMINISH BY TUESDAY AND SHOULD REMAIN SUB SCA FOR THE REMAINDER OF THE FORECAST. OCCASIONAL HIGHER GUSTS POSSIBLE WITH THE PASSAGE OF THE FRONT ON WED. && .HYDROLOGY... SIGNIFICANT PRECIPITATION IS NOT EXPECTED THROUGH SUNDAY NIGHT. A PROLONGED PERIOD OF STRATIFORM RAIN IS POSSIBLE FROM LATE MONDAY NIGHT INTO WEDNESDAY. SINCE THIS WILL BE A LONG DURATION EVENT AND HEAVY RAIN IS NOT EXPECTED AT THIS TIME...FLOODING DOES NOT APPEAR TO BE A CONCERN. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...SEARS NEAR TERM...MALOIT SHORT TERM...SEARS LONG TERM...SEARS AVIATION...BC/JMC MARINE...MALOIT/SEARS HYDROLOGY...SEARS
AREA FORECAST DISCUSSION
NWS MIAMI FL
204 PM EDT SUN SEP 30 2012 .AVIATION...VFR WILL PREVAIL. EAST COAST SEA BREEZE HAS MOVED INLAND FROM THE EAST COAST TERMINALS SO REMOVED VCTS THERE, BUT KEPT IT FOR KAPF AS TSTORMS COULD BE IN THE VICINITY. INCLUDED VCSH ALL EAST COAST TERMINALS OVERNIGHT. SHOWERS ARE MOST LIKELY IN THE VICINITY TOWARDS DAWN MON. VCTS ALL TERMINALS FOR MON. IT COULD BECOME WET AND MAY NEED TO ADD TEMPO`S DOWN THE ROAD. BRIEF IFR POSSIBLE MON. ONSHORE WINDS WILL BECOME LIGHT OVERNIGHT THEN SOUTHERLY ON MON. /GREGORIA && .PREV DISCUSSION... /ISSUED 1022 AM EDT SUN SEP 30 2012/ UPDATE...BASED ON CURRENT TRENDS AND OBSERVATIONS, DO NOT PLAN TO MAKE ANY CHANGES WITH THE MORNING UPDATES. THE 12Z MFL SOUNDING WAS CONTAMINATED IN THE LOWEST LEVELS SO THE PWAT VALUE WAS CALCULATED WAY TOO LOW. HOWEVER, IT DOES SHOW A GENERAL INCREASE IN MOISTURE THROUGH THE MID LEVELS AND BASED ON THIS IT APPEARS THE PWAT HAS PROBABLY INCREASED BACK CLOSE TO TWO INCHES. IT DEPICTS ONLY A MARGINALLY UNSTABLE AIRMASS SO THE 30-40 PERCENT POPS LOOK REASONABLE. THE HRRR DOES INDICATE NNW STORM MOTION WITH SCATTERED COVERAGE AND THIS ALSO SEEMS REASONABLE GIVEN ABOVE DISCUSSION. KOB PREV DISCUSSION... /ISSUED 727 AM EDT SUN SEP 30 2012/ AVIATION...ISOLATED SHRA MOVING NW THROUGH THE ATLC WATERS AND GULF WATERS AT THIS TIME WITH THE ACTIVITY OCCASIONALLY MOVING UPON THE E COAST. HAVE VCSH INITIALLY IN E COAST TAFS AND VERY BRIEF MVFR CIG POSSIBLE. CURRENT E COAST SURFACE WINDS CALM TO LIGHT SE WITH SEA BREEZE INCREASING SE 10 TO 12 KNOTS AFT 16Z. TSRA TO DEVELOP MAINLY ALONG THE SEA BREEZE WITH VCTS IN TAFS AFT 17/18Z. TSRA MAY BE FAR ENOUGH INLAND TO AFFECT ONLY KTMB AND KPBI. AT KAPF ...SHRA SHOULD REMAIN OFFSHORE WITH VCTS IN TAFS AFT 18Z THROUGH 30/00Z. AT KAPF CURRENT SURFACE WIND CALM BECOMING ESE-SE < 10 KNOTS AFT 13Z THEN SSW-SW TO 10 KNOTS AFT 16Z AS W COAST SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 307 AM EDT SUN SEP 30 2012/ POTENTIAL FOR HEAVY RAIN AND LOCALIZED FLOODING ACROSS SOUTH FLORIDA MONDAY AND TUESDAY... DISCUSSION... WATER VAPOR ANALYSIS FROM THIS MORNING SHOWED A LARGE UPPER LOW SPINNING OVER THE LOWER GREAT LAKES...AND ANOTHER CUT OFF LOW OVER OKLAHOMA. UPPER LEVEL HIGH PRESSURE WAS LOCATED ACROSS THE PACIFIC AND WEST COAST AND OUT ACROSS THE WESTERN ATLANTIC. AT THE SURFACE...LOW PRESSURE WAS LOCATED ACROSS EAST TEXAS AND A WEAK FRONT WAS ACROSS THE SOUTHEAST AND INTO THE WESTERN ATLANTIC. A WEAK RIDGE AXIS WAS LOCATED FROM THE WESTERN ATLANTIC ACROSS THE LAKE OKEECHOBEE REGION. FOR SOUTH FLORIDA...LOW LEVEL SOUTHEAST FLOW HAS BEGUN...BUT DEEP MOISTURE WAS STILL LOCATED OVER THE CARIBBEAN. SOME DRIER AIR WAS ALSO NOTED OVER THE YUCATAN NORTHEASTWARD TO OFF WEST COAST OF SOUTH FLORIDA. A SHORTWAVE IS EXPECTED TO DIVE SOUTHEAST ACROSS THE PACIFIC NORTHWEST...AND THE CUT OFF LOW IS EXPECTED TO DEEPEN ACROSS THE ARKLATEX REGION. THIS WILL AMPLIFY THE UPPER PATTERN THROUGH THE MIDDLE OF THE WEEK...WITH A DEEP TROUGH ACROSS THE SOUTH AND STRONG RIDGES ACROSS THE WEST COAST AND OVER THE WESTERN ATLANTIC. DEEP SOUTH TO SOUTHWEST FLOW WILL DEVELOP OVER SOUTH FLORIDA...PULLING TROPICAL MOISTURE OUT OF THE CARIBBEAN OVER THE REGION LATE TONIGHT THROUGH TUESDAY. SINCE MODELS HAVE SLOWED DOWN THE TIMING OF THE DEEP TROPICAL MOISTURE UNTIL TONIGHT...AND WITH WARM AND DRY AIR ALOFT...500MB TEMPS AROUND -4C TO -5C...CUT BACK POPS SLIGHTLY FOR TODAY. WENT WITH A BLEND OF MAV AND ECMWF FOR THE POPS...WITH STILL A CHANCE OF STORMS ACROSS THE REGION. EXPECT MAINLY SEA BREEZE ACTIVITY...WITH OVERALL STORM MOTION SLOW TO THE NORTH. THE UPPER LOW OVER THE NORTHEAST CONUS WILL SLOWLY SLIDE TO THE NORTHEAST...AND SURFACE LOW PRESSURE WILL MOVE ACROSS THE NORTHERN GULF AND INTO THE SOUTHEAST STATES EARLY NEXT WEEK. A COLD FRONT ATTACHED TO THE SURFACE LOW WILL MOVE INTO THE CENTRAL/EASTERN GULF ON MONDAY AND THEN INTO CENTRAL FLORIDA AND NEAR LAKE OKEECHOBEE ON TUESDAY. SO FOR MONDAY...PWATS WILL INCREASE TO AROUND 2.1-2.4 INCHES...AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. ALTHOUGH STORM MOTION IS NOT TERRIBLY SLOW...AROUND 10 KNOTS TO THE NORTHEAST...WITH THE DEEP MOISTURE AND SATURATED SOILS ACROSS SOUTH FLORIDA THERE WILL A POTENTIAL FOR LOCALLY HEAVY RAINFALL. HPC PAINTS AROUND 1 INCH OF RAIN AREAL AVERAGE ACROSS THE ENTIRE EASTERN TWO-THIRDS OF SOUTH FLORIDA...SO LOCALIZED SPOTS COULD SEE 2 TO 4 INCHES OF RAIN AND POSSIBLY MORE. SO LOCALIZED FLOODING IS THE BIGGEST CONCERN. FLASH FLOOD GUIDANCE IS NOT STILL RELATIVELY HIGH...3-4 INCHES FOR 1 HOUR...AROUND 4 INCHES FOR 3 HOURS...AND 4-5.5 INCHES FOR 6 HOURS. WITH NO REAL FOCUS FOR STORMS AND CLOUD COVER POSSIBLY HAMPERING OVERALL ACTIVITY...WILL NOT ISSUE A FLOOD WATCH AT THIS TIME. WENT BELOW GUIDANCE BY A FEW DEGREES FOR HIGH TEMPERATURES DUE TO EXPECTED CLOUD COVER AND RAINFALL ON MONDAY. SOME OF THE DRIER AIR PREVIOUSLY MENTIONED ACROSS THE EASTERN GULF AND TOWARDS THE YUCATAN MAY TRY TO PUSH INTO THE GULF COAST OF SOUTH FLORIDA MONDAY NIGHT DUE TO THE SOUTHWEST FLOW ALOFT. HOWEVER...HIGH PRESSURE ACROSS THE WESTERN ATLANTIC WILL BEGIN TO STRENGTHEN AND BATTLE BACK AGAINST THE TROUGH OVER THE SOUTH...AND THE DEEP MOISTURE IS FORECAST TO PUSH BACK ACROSS AT LEAST THE EASTERN TWO-THIRDS OF THE REGION ON TUESDAY. HEIGHTS WILL BEGIN TO RISE ACROSS THE REGION...BUT THERE WILL BE ANOTHER CHANCE FOR LOCALLY HEAVY RAINFALL...MAINLY FOR THE EAST COAST METRO AREAS. HIGH PRESSURE WILL CONTINUE TO STRENGTHEN ACROSS THE WESTERN ATLANTIC TUESDAY NIGHT INTO WEDNESDAY WITH HEIGHTS OF 596-598 DECAMETERS...AND 592-593 DECAMETERS ACROSS SOUTH FLORIDA. THE FLOW WILL BECOME MORE SOUTHEASTERLY AS HIGH PRESSURE BUILDS IN...AND THE DEEP MOISTURE WILL BEGIN TO GET PUSHED TO THE NORTHWEST. PWATS WILL FALL TO 1.8 TO 2 INCHES ACROSS THE REGION...HIGHEST ACROSS THE NORTHWEST. THE PERSISTENT TROUGH OVER THE DEEP SOUTH WILL BEGIN TO LIFT TO THE NORTHEAST AS ANOTHER TROUGH DIGS INTO THE NORTHERN PLAINS ON THURSDAY...AND HIGH PRESSURE WILL BEGIN TO WEAKEN OVER THE WESTERN ATLANTIC. SURFACE HIGH PRESSURE WILL DEVELOP OVER THE SOUTHEAST AND EASTERLY FLOW WILL DEVELOP ACROSS THE REGION...WITH MORE TYPICAL SEA BREEZE TYPE CONVECTION. HOWEVER...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL FLORIDA OR NEAR LAKE OKEECHOBEE...KEEPING RELATIVELY HIGH LEVELS OF MOISTURE...PWATS NEAR 2 INCHES...INTO THE WEEKEND. SO RAIN CHANCES WILL REMAIN AT OR ABOVE NORMAL THROUGH NEXT SATURDAY. TEMPERATURES ARE EXPECTED TO REMAIN NEAR NORMAL THROUGH THE PERIOD. AVIATION...FOR 06Z TAFS. WIDELY SCATTERED SHRA MOVING NW THROUGH THE ATLC WATERS AND GULF WATERS WITH THE ACTIVITY OCCASIONALLY MOVING UPON THE E COAST. VERY BRIEF MVFR CIG POSSIBLE. VCSH IN E COAST TAFS. E COAST SEA BREEZE INCREASES SE WINDS AFT 16Z AND TSRA TO DEVELOP MAINLY ALONG THE SEA BREEZE WITH VCTS IN TAFS. POTENTIAL THAT TSRA MAY BE FAR ENOUGH INLAND TO AFFECT MAINLY KTMB AND KPBI. AT KAPF...SHRA SHOULD REMAIN OFFSHORE WITH VCTS AFT 18Z THROUGH 30/00Z. E COAST SURFACE WINDS CURRENTLY CALM TO SE-SSE < 5 KNOTS UNLESS BECOMING VARIABLE FOR A SHORT PERIOD OF TIME IF A SHRA MOVES OVER THE AREA...BECOMING SE 10-12 KNOTS AFT 15Z. AT KAPF CURRENT SURFACE WIND CALM TO SE < 5 KNOTS INCREASING AFT 12Z 5 TO 8 KNOTS THEN SHIFTING SSW-SW TO 10 KNOTS AFT 16Z AS W COAST SEA BREEZE DEVELOPS. MARINE... WIND AND SEAS WILL REMAIN QUITE TRANQUIL THROUGH THE WEEKEND WITH LIGHT SOUTHEAST FLOW BECOMING MORE SOUTHERLY ON SUNDAY. A STRONGER SOUTH WIND WILL BEGIN TO DEVELOP MONDAY AND TUESDAY IN RESPONSE TO THE DEVELOPING LOW PRESSURE WITH SEAS POSSIBLY BUILDING TO AROUND 4 FEET. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH HIGH LOW LEVEL MOISTURE IN PLACE THIS WEEKEND AND ALL OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 77 87 77 / 30 30 70 50 FORT LAUDERDALE 89 76 86 77 / 30 40 70 50 MIAMI 88 78 86 77 / 30 40 70 50 NAPLES 89 77 89 77 / 20 20 60 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
242 PM CDT SUN SEP 30 2012 .DISCUSSION... 1111 AM CDT FOR MORNING UPDATE... ONLY MINOR TWEAKS TO HOURLY SKY COVER GRIDS MADE THIS MORNING...WITH FORECAST GENERALLY RIGHT ON TRACK. COLD FRONT WHICH PASSED ACROSS THE AREA LAST EVENING WAS OVER THE OHIO VALLEY AT MID-MORNING...WITH WEAK HIGH PRESSURE SPREADING ACROSS THE NORTHERN GREAT LAKES. NORTHEAST SURFACE WINDS WERE PROVIDING COOLER LOW LEVEL AIR TO THE REGION...WITH A SOME LAKE-INDUCED STRATOCU MOVING INLAND OFF OF LAKE MICHIGAN INTO NORTHEAST IL. STRATOCU LAYER IS EXPECTED TO DECREASE IN COVERAGE AS WE HEAD INTO THE AFTERNOON HOURS...THANKS TO WARMING TEMPS ABOVE THE BOUNDARY LAYER IN RESPONSE TO LARGE SCALE SUBSIDENCE ASSOCIATED WITH AFOREMENTIONED HIGH PRESSURE IN THE WAKE OF STRONG VORT MOVING AWAY OVER OHIO. THUS MODEST NORTHEAST WINDS WILL LIKELY HOLD TEMPS INTO THE LOW-MID 60S ALONG THE LAKE MICHIGAN SHORES...WHILE AREAS WELL INLAND WARM TO AROUND 70 OR THE LOWER 70S FAR WEST UNDER GENERALLY MOSTLY SUNNY SKIES DURING THE AFTERNOON. RATZER //PREV DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY ENELY-NELY WINDS TO G15-20KT THROUGH EARLY EVENING. KREIN //DISCUSSION...UPDATED 18Z... A BKN MVFR DECK OF LAKE EFFECT CLOUDINESS MOVED ONSHORE THIS MORNING AND COOL HIGH PRESSURE AS HIGH PRESSURE PUSHED SWD DOWN LAKE MICHIGAN. LATEST VISIBLE SATELLITE IMAGERY SHOWS A SHARP BACK EDGE OF THE CLOUD DECK PUSHING INLAND AS THE CLOUD DECK THINS WITH DEEP LAYER MIXING THROUGH THE LATE MORNING HOURS. EXPECT ANY REMAINING CLOUD THIS AFTERNOON TO BE FEW TO SCT. THE DEEP LAYER MIXING IS GENERATING GUSTS TO ARND 20KT WITH AN OCNL HIGHER GUST. EXPECT THAT THE GUSTINESS SHOULD SUBSIDE WITH SUNSET. AS THE HIGH PRESSURE CONTINUES TO BUILD SOUTH OVER THE REGION...WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT. UNDER CLEAR SKIES AND LIGHT WINDS...SOME SHALLOW GROUND FOG MAY FORM IN LOW LYING AREAS...BUT SHOULD NOT IMPACT ORD/MDW/GYY. THERE IS A CHANCE SOME MIFG COULD DRIFT OVER RFD/DPA...BUT WILL LEAVE OUT OF THE TAFS FOR NOW AS IT WOULD LIKELY NOT HAVE AN OPERATIONAL IMPACT. WINDS SHOULD TURN MORE SELY TOMORROW AS LOW PRESSURE TRACKS NWD THROUGH THE OHIO VALLEY. THIS WILL BRING INCREASING CI THOUGH THE DAY TOMORROW...AND COULD BRING INCREASING MID CLOUD AS WELL...BUT LIKELY NOT UNTIL AFTER THE END OF THE FORECAST PERIOD. KREIN //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN SUSTAINED WIND SPEED/DIRECTION. * MODERATE CONFIDENCE IN MAX SPEED AND DURATION OF GUSTS. * MODERATE TO HIGH CONFIDENCE THAT ANY MIFG THAT FORMS IN THE REGION WILL NOT IMPACT THE ORD/MDW TERMINALS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 242 PM...A WEAK RIDGE OF HIGH PRESSURE WILL MOVE SOUTH ACROSS LAKE MICHIGAN TONIGHT. NORTHEAST WINDS WILL SLOWLY DIMINISH THIS EVENING AND BEGIN TO TURN SOUTHERLY FROM NORTH TO SOUTH MONDAY MORNING. A COLD FRONT WILL MOVE ACROSS THE WESTERN LAKES MONDAY INTO MONDAY EVENING AND THE GRADIENT WILL TIGHTEN SOME AHEAD OF THIS FRONT WITH SOUTHERLY WINDS PERHAPS AS HIGH AS 10-20 KTS ACROSS THE NORTHERN PART OF THE LAKE MONDAY AFTERNOON/EVENING. THIS FRONT WILL MOVE ACROSS NORTHERN LAKE MICHIGAN TUESDAY NIGHT AS IT SLOWS AND IS THEN ABSORBED AS LOW PRESSURE CURRENTLY OVER LOUISIANA LIFTS NORTH ACROSS THE OHIO VALLEY ON TUESDAY AND THEN ACROSS THE SOUTHERN LAKES REGION TUESDAY NIGHT. WINDS WILL TURN NORTHEASTERLY ACROSS THE ENTIRE LAKE DURING THIS TIME WITH 10-20 KTS LIKELY OVER THE SOUTHERN HALF OF THE LAKE. THIS LOW WILL WEAKEN AS IT CONTINUES MOVING NORTH ON WEDNESDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY AND WEDNESDAY NIGHT...REACHING THE WESTERN LAKES REGION ON THURSDAY. THERE STILL REMAINS SOME UNCERTAINTY REGARDING THE TIMING OF THIS FRONT. IF NEW LOW PRESSURE DEVELOPS ALONG THE FRONT OVER MINNESOTA AND WISCONSIN...THE FRONT WILL LIKELY SLOW AND NOT REACH LAKE MICHIGAN UNTIL LATE THURSDAY AFTERNOON OR THURSDAY EVENING. SHOULD NO NEW LOW PRESSURE DEVELOP...THE FRONT COULD SPEED UP AND ARRIVE AS EARLY AS THURSDAY MORNING. SOUTHERLY FLOW AHEAD OF THE FRONT IS EXPECTED AND COULD BECOME STRONGER WITH A SLOWER FRONTAL PASSAGE. COLDER AIR BEHIND THE FRONT ALONG WITH THE POSSIBILITY OF A DEEPENING LOW MOVING INTO ONTARIO WILL LIKELY LEAD TO STRONG WINDS TO 30 KTS...ESPECIALLY ON THE NORTH END OF THE LAKE. GALES ARE ALSO POSSIBLE DURING THIS TIME PERIOD BUT TOO MUCH UNCERTAINTY TO INCLUDE JUST YET. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
230 PM CDT SUN SEP 30 2012 .DISCUSSION... 1111 AM CDT FOR MORNING UPDATE... ONLY MINOR TWEAKS TO HOURLY SKY COVER GRIDS MADE THIS MORNING...WITH FORECAST GENERALLY RIGHT ON TRACK. COLD FRONT WHICH PASSED ACROSS THE AREA LAST EVENING WAS OVER THE OHIO VALLEY AT MID-MORNING...WITH WEAK HIGH PRESSURE SPREADING ACROSS THE NORTHERN GREAT LAKES. NORTHEAST SURFACE WINDS WERE PROVIDING COOLER LOW LEVEL AIR TO THE REGION...WITH A SOME LAKE-INDUCED STRATOCU MOVING INLAND OFF OF LAKE MICHIGAN INTO NORTHEAST IL. STRATOCU LAYER IS EXPECTED TO DECREASE IN COVERAGE AS WE HEAD INTO THE AFTERNOON HOURS...THANKS TO WARMING TEMPS ABOVE THE BOUNDARY LAYER IN RESPONSE TO LARGE SCALE SUBSIDENCE ASSOCIATED WITH AFOREMENTIONED HIGH PRESSURE IN THE WAKE OF STRONG VORT MOVING AWAY OVER OHIO. THUS MODEST NORTHEAST WINDS WILL LIKELY HOLD TEMPS INTO THE LOW-MID 60S ALONG THE LAKE MICHIGAN SHORES...WHILE AREAS WELL INLAND WARM TO AROUND 70 OR THE LOWER 70S FAR WEST UNDER GENERALLY MOSTLY SUNNY SKIES DURING THE AFTERNOON. RATZER //PREV DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY ENELY-NELY WINDS TO G15-20KT THROUGH EARLY EVENING. KREIN //DISCUSSION...UPDATED 18Z... A BKN MVFR DECK OF LAKE EFFECT CLOUDINESS MOVED ONSHORE THIS MORNING AND COOL HIGH PRESSURE AS HIGH PRESSURE PUSHED SWD DOWN LAKE MICHIGAN. LATEST VISIBLE SATELLITE IMAGERY SHOWS A SHARP BACK EDGE OF THE CLOUD DECK PUSHING INLAND AS THE CLOUD DECK THINS WITH DEEP LAYER MIXING THROUGH THE LATE MORNING HOURS. EXPECT ANY REMAINING CLOUD THIS AFTERNOON TO BE FEW TO SCT. THE DEEP LAYER MIXING IS GENERATING GUSTS TO ARND 20KT WITH AN OCNL HIGHER GUST. EXPECT THAT THE GUSTINESS SHOULD SUBSIDE WITH SUNSET. AS THE HIGH PRESSURE CONTINUES TO BUILD SOUTH OVER THE REGION...WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT. UNDER CLEAR SKIES AND LIGHT WINDS...SOME SHALLOW GROUND FOG MAY FORM IN LOW LYING AREAS...BUT SHOULD NOT IMPACT ORD/MDW/GYY. THERE IS A CHANCE SOME MIFG COULD DRIFT OVER RFD/DPA...BUT WILL LEAVE OUT OF THE TAFS FOR NOW AS IT WOULD LIKELY NOT HAVE AN OPERATIONAL IMPACT. WINDS SHOULD TURN MORE SELY TOMORROW AS LOW PRESSURE TRACKS NWD THROUGH THE OHIO VALLEY. THIS WILL BRING INCREASING CI THOUGH THE DAY TOMORROW...AND COULD BRING INCREASING MID CLOUD AS WELL...BUT LIKELY NOT UNTIL AFTER THE END OF THE FORECAST PERIOD. KREIN //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN SUSTAINED WIND SPEED/DIRECTION. * MODERATE CONFIDENCE IN MAX SPEED AND DURATION OF GUSTS. * MODERATE TO HIGH CONFIDENCE THAT ANY MIFG THAT FORMS IN THE REGION WILL NOT IMPACT THE ORD/MDW TERMINALS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1223 PM CDT SUN SEP 30 2012 .DISCUSSION... 1111 AM CDT FOR MORNING UPDATE... ONLY MINOR TWEAKS TO HOURLY SKY COVER GRIDS MADE THIS MORNING...WITH FORECAST GENERALLY RIGHT ON TRACK. COLD FRONT WHICH PASSED ACROSS THE AREA LAST EVENING WAS OVER THE OHIO VALLEY AT MID-MORNING...WITH WEAK HIGH PRESSURE SPREADING ACROSS THE NORTHERN GREAT LAKES. NORTHEAST SURFACE WINDS WERE PROVIDING COOLER LOW LEVEL AIR TO THE REGION...WITH A SOME LAKE-INDUCED STRATOCU MOVING INLAND OFF OF LAKE MICHIGAN INTO NORTHEAST IL. STRATOCU LAYER IS EXPECTED TO DECREASE IN COVERAGE AS WE HEAD INTO THE AFTERNOON HOURS...THANKS TO WARMING TEMPS ABOVE THE BOUNDARY LAYER IN RESPONSE TO LARGE SCALE SUBSIDENCE ASSOCIATED WITH AFOREMENTIONED HIGH PRESSURE IN THE WAKE OF STRONG VORT MOVING AWAY OVER OHIO. THUS MODEST NORTHEAST WINDS WILL LIKELY HOLD TEMPS INTO THE LOW-MID 60S ALONG THE LAKE MICHIGAN SHORES...WHILE AREAS WELL INLAND WARM TO AROUND 70 OR THE LOWER 70S FAR WEST UNDER GENERALLY MOSTLY SUNNY SKIES DURING THE AFTERNOON. RATZER //PREV DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * GUSTY ENELY-NELY WINDS TO G15-20KT THROUGH EARLY EVENING. * SCT LAKE EFFECT CLOUDINESS THROUGH THE AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... A BKN MVFR DECK OF LAKE EFFECT CLOUDINESS MOVED ONSHORE THIS MORNING AND COOL HIGH PRESSURE AS HIGH PRESSURE PUSHED SWD DOWN LAKE MICHIGAN. LATEST VISIBLE SATELLITE IMAGERY SHOWS A SHARP BACK EDGE OF THE CLOUD DECK PUSHING INLAND AS THE CLOUD DECK THINS WITH DEEP LAYER MIXING THROUGH THE LATE MORNING HOURS. EXPECT ANY REMAINING CLOUD THIS AFTERNOON TO BE FEW TO SCT. THE DEEP LAYER MIXING IS GENERATING GUSTS TO ARND 20KT WITH AN OCNL HIGHER GUST. EXPECT THAT THE GUSTINESS SHOULD SUBSIDE WITH SUNSET. AS THE HIGH PRESSURE CONTINUES TO BUILD SOUTH OVER THE REGION...WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT. UNDER CLEAR SKIES AND LIGHT WINDS...SOME SHALLOW GROUND FOG MAY FORM IN LOW LYING AREAS...BUT SHOULD NOT IMPACT ORD/MDW/GYY. THERE IS A CHANCE SOME MIFG COULD DRIFT OVER RFD/DPA...BUT WILL LEAVE OUT OF THE TAFS FOR NOW AS IT WOULD LIKELY NOT HAVE AN OPERATIONAL IMPACT. WINDS SHOULD TURN MORE SELY TOMORROW AS LOW PRESSURE TRACKS NWD THROUGH THE OHIO VALLEY. THIS WILL BRING INCREASING CI THOUGH THE DAY TOMORROW...AND COULD BRING INCREASING MID CLOUD AS WELL...BUT LIKELY NOT UNTIL AFTER THE END OF THE FORECAST PERIOD. KREIN //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SUSTAINED WIND SPEED/DIRECTION. * MODERATE CONFIDENCE IN MAX SPEED AND DURATION OF GUSTS. * MODERATE TO HIGH CONFIDENCE THAT ANY MIFG THAT FORMS IN THE REGION WILL NOT IMPACT THE ORD/MDW TERMINALS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1118 AM CDT SUN SEP 30 2012 .DISCUSSION... 1111 AM CDT FOR MORNING UPDATE... ONLY MINOR TWEAKS TO HOURLY SKY COVER GRIDS MADE THIS MORNING...WITH FORECAST GENERALLY RIGHT ON TRACK. COLD FRONT WHICH PASSED ACROSS THE AREA LAST EVENING WAS OVER THE OHIO VALLEY AT MID-MORNING...WITH WEAK HIGH PRESSURE SPREADING ACROSS THE NORTHERN GREAT LAKES. NORTHEAST SURFACE WINDS WERE PROVIDING COOLER LOW LEVEL AIR TO THE REGION...WITH A SOME LAKE-INDUCED STRATOCU MOVING INLAND OFF OF LAKE MICHIGAN INTO NORTHEAST IL. STRATOCU LAYER IS EXPECTED TO DECREASE IN COVERAGE AS WE HEAD INTO THE AFTERNOON HOURS...THANKS TO WARMING TEMPS ABOVE THE BOUNDARY LAYER IN RESPONSE TO LARGE SCALE SUBSIDENCE ASSOCIATED WITH AFOREMENTIONED HIGH PRESSURE IN THE WAKE OF STRONG VORT MOVING AWAY OVER OHIO. THUS MODEST NORTHEAST WINDS WILL LIKELY HOLD TEMPS INTO THE LOW-MID 60S ALONG THE LAKE MICHIGAN SHORES...WHILE AREAS WELL INLAND WARM TO AROUND 70 OR THE LOWER 70S FAR WEST UNDER GENERALLY MOSTLY SUNNY SKIES DURING THE AFTERNOON. RATZER //PREV DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LAKE EFFECT MVFR CIGS ENDING BY 18Z. A SHARP BACK EDGE TO THE BKN DECK OBSERVED ON SATELLITE IMAGERY. * GUSTY NORTHEAST WINDS TO G15-18KT THROUGH EARLY EVENING. * SMALL CHANCE FOR MVFR CIGS TONIGHT AND EARLY MONDAY MORNING. KREIN //DISCUSSION...UPDATED 12Z... THE TERMINALS LIE BETWEEEN A COLD FRONT TO THE SOUTH WHICH PASSED LATE YESTERDAY AND HIGH PRESSURE ACROSS ONTARIO AND QUEBEC. THE GRADIENT BETWEEN THESE FEATURES WILL CONTINUE TO FAVOR A NORTHEAST SYNOPTIC WIND. INITIALLY...THROUGH 14Z...A SLIGHTLY MORE NNW WIND WILL BE SEEN ACROSS NORTHEAST IL DUE TO A REMNANT LAND BREEZE FROM THE NIGHT. THIS IS AIDING CONVERGENCE INTO NORTHEAST IL THAT SHOULD HELP TO FOCUS DEVELOPING CLOUDS OVER THE LAKE INTO NORTHEAST IL BY MID MORNING...AND LIKELY TOWARD GYY AS WELL. THESE LAKE ENHANCED CLOUDS ARE PRESENTLY FAVORED TO BE AT OR ABOVE 2000 FT BY THE TIME THEY ARRIVE AT THE TERMINALS...BUT AT ONSET SOME COULD BE BELOW 2000 FT. THAT SHOULD BE BRIEF IF THAT OCCURS. CLOUDS SHOULD GRADUALLY BECOME MORE SCATTERED THROUGH THE AFTERNOON AS THE COLD AIR ADVECTION COMPONENT OVER THE WATER WEAKENS. THE HIGH PRESSURE WILL SETTLE SOUTHWARD OVER THE AREA THIS EVENING...WITH RETURN FLOW DEVELOPING ON MONDAY. //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN BROKEN CLOUDS BETWEEN 2000 AND 3500 FT. MEDIUM CONFIDENCE IN TIMING. LOW CONFIDENCE IN ANY CIGS BELOW 2000 FT. * HIGH CONFIDENCE IN WIND DIRECTIONAL TRENDS. MEDIUM CONFIDENCE IN MAXIMUM GUST SPEED. * LOW CONFIDENCE IN ANY RETURNING BROKEN CIGS TONIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1112 AM CDT SUN SEP 30 2012 .DISCUSSION... 1111 AM CDT FOR MORNING UPDATE... ONLY MINOR TWEAKS TO HOURLY SKY COVER GRIDS MADE THIS MORNING...WITH FORECAST GENERALLY RIGHT ON TRACK. COLD FRONT WHICH PASSED ACROSS THE AREA LAST EVENING WAS OVER THE OHIO VALLEY AT MID-MORNING...WITH WEAK HIGH PRESSURE SPREADING ACROSS THE NORTHERN GREAT LAKES. NORTHEAST SURFACE WINDS WERE PROVIDING COOLER LOW LEVEL AIR TO THE REGION...WITH A SOME LAKE-INDUCED STRATOCU MOVING INLAND OFF OF LAKE MICHIGAN INTO NORTHEAST IL. STRATOCU LAYER IS EXPECTED TO DECREASE IN COVERAGE AS WE HEAD INTO THE AFTERNOON HOURS...THANKS TO WARMING TEMPS ABOVE THE BOUNDARY LAYER IN RESPONSE TO LARGE SCALE SUBSIDENCE ASSOCIATED WITH AFOREMENTIONED HIGH PRESSURE IN THE WAKE OF STRONG VORT MOVING AWAY OVER OHIO. THUS MODEST NORTHEAST WINDS WILL LIKELY HOLD TEMPS INTO THE LOW-MID 60S ALONG THE LAKE MICHIGAN SHORES...WHILE AREAS WELL INLAND WARM TO AROUND 70 OR THE LOWER 70S FAR WEST UNDER GENERALLY MOSTLY SUNNY SKIES DURING THE AFTERNOON. RATZER && .PREV DISCUSSION... 338 AM CDT MAIN FORECAST CHALLENGES THIS MORNING ARE WITH LAKE EFFECT CLOUD POTENTIAL NOW THROUGH LATE MORNING TODAY...WITH MOSTLY SUNNY SKIES THEN EXPECTED FOR THE ENTIRE AREA INTO THE AFTERNOON AS TEMPS RISE TO THE UPPER 60S AND LOW 70S. LATEST WATER VAPOR IMAGERY DEPICTING A FAIRLY STRONG PIECE OF MID LEVEL ENERGY WRAPPING AROUND THE CLOSED UPPER LEVEL SYSTEM ACROSS THE EASTERN GREAT LAKES REGION THIS MORNING. AS THIS OCCURS...COLDER AIR WILL CONTINUE TO WORK ITS WAY SOUTHWEST OVER THE LAKE THIS MORNING AND ACROSS THE CWA THROUGH THE AFTERNOON. WHAT THIS WILL MEAN FOR TODAY IS SLIGHTLY COOLER HIGH TEMPERATURES ACROSS THE CWA AS WELL AS THE POTENTIAL FOR SOME LAKE EFFECT CLOUD COVER TO SPILL INTO AREAS NEAR THE LAKE IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA. AS WAS EXPECTED...LATEST RAP ANALYSIS SHOWING DELTA TS FINALLY INCREASING ACROSS THE ENTIRE LENGTH OF THE LAKE...WITH THIS TREND TO CONTINUE THROUGH THE REMAINDER OF THE MORNING. ALTHOUGH LATEST SATELLITE IMAGERY SHOWING THIS CLOUD COVER SOMEWHAT SLOW TO DEVELOP OVER THE NORTHERN PORTIONS OF THE LAKE...SHOULD BEGIN TO SEE AN INCREASE IN THIS DEVELOPMENT OVER THE NEXT TWO TO THREE HOURS. FAVORED LOW LEVEL FLOW SHOULD KEEP MOST OF ANY CLOUD COVER OVER AREAS IN FAR NORTHEAST ILLINOIS...BUT WITH SOME CLOUD COVER TO STILL POSSIBLY SPILL OVER INTO AREAS IN FAR NORTHWEST INDIANA. ALTHOUGH THIS CLOUD COVER IS EXPECTED TO DEVELOP AND MOVE ACROSS AREAS NEAR THE LAKE...IT SHOULDNT BE MORE THAN PARTLY CLOUDY SKIES WITH SOME BRIEF PERIODS OF PARTLY SUNNY/CLOUDY CONDITIONS THROUGH THE 15Z TIME FRAME. AFTER THIS TIME FRAME...CLOUD COVER SHOULD BEGIN TO DIMINISH INTO THE AFTERNOON AS HIGHER PRESSURE SHIFTS DOWN THE LAKE. AFTER THIS POINT...SKIES SHOULD BE MOSTLY SUNNY INTO THE AFTERNOON WITH ANOTHER PLEASANT DAY IN STORE. ALTHOUGH TEMPS TODAY WILL BE SLIGHTLY COOLER THAN YESTERDAY...I DID RAISE TEMPS A COUPLE OF DEGREES OVER GUIDANCE WITH TEMPERATURES RISING INTO THE LOW 70S FOR MOST AREAS IN NORTHERN ILLINOIS...WITH TEMPS SLIGHTLY COOLER IN THE UPPER 60S IF NOT AROUND 70 MARK FOR AREAS NEAR THE LAKE. NONETHELESS...A PLEASANT DAY WILL BE IN STORE FOR THE AREA TODAY. AFTER QUIET CONDITIONS ONCE AGAIN TONIGHT INTO THE EARLY PORTIONS OF MONDAY...A SOMEWHAT MORE ACTIVE WEATHER APPEARS TO BE ON THE HORIZON. AS MID AND HIGH LEVEL CLOUD INCREASES FROM THE SOUTH ON MONDAY...TEMPS SHOULD STILL RISE INTO THE LOW 70S ON MONDAY. ALTHOUGH AS WAS EXPECTED OVER THE LAST 24 HOURS...MODELS CONTINUE TO TREND TOWARDS BRINGING CURRENT CLOSED UPPER LEVEL LOW OVER THE SOUTHERN PLAINS NORTHEAST TOWARDS THE AREA BY LATE MONDAY. MODEL CONSENSUS SEEMS TO BRING THIS UPPER LEVEL SYSTEM AND SURFACE REFLECTION UP THROUGH THE TENNESSEE VALLEY LATE MONDAY INTO EARLY TUESDAY MORNING...AS A SEPARATE MID LEVEL TROUGH APPROACHES FROM THE NORTHERN PLAINS. ALTHOUGH WITH A LACK OF MOISTURE WITH THIS NORTHERN STREAM MID LEVEL TROUGH...PRECIP SHOULD BE DIMINISHING AS IT APPROACHES THE CWA. BEST CHANCES FOR SHOWERS WILL BE FOR AREAS ACROSS THE SOUTHEAST CWA MONDAY NIGHT. THIS SYSTEM WILL SLOWLY SPIN ACROSS THE REGION...WITH PRECIP POSSIBLY LINGERING ACROSS THE SAME AREA TUESDAY INTO TUESDAY NIGHT. CURRENT FORECAST KEEPS PRECIP CHANCES THROUGH LATE IN THE DAY TUESDAY...BUT ITS CONCEIVABLE THAT THIS SYSTEM WILL TAKE A SLOWER EASTWARD MOVEMENT. IF THIS WERE TO OCCUR...PRECIP COULD LINGER INTO THE MIDDLE PART OF THE WEEK BEFORE EXITING. AFTER WEAK RIDGING AND A SLIGHT INCREASE IN TEMPS ON WEDNESDAY...ANOTHER MID LEVEL SYSTEM AND SURFACE REFLECTION/FRONTAL BOUNDARY WILL APPROACH THE CWA WITH PRECIP CHANCES INCREASING ONCE AGAIN TOWARDS THE END OF THE WORK WEEK. IT WOULD APPEAR THAT MAINLY SHOWERS SHOULD BE OBSERVED AS THIS SYSTEM PUSHES THROUGH THE AREA ON THURSDAY...BUT WITH SOME UNCERTAINTY AS TO THE OVERALL AMOUNT OF MOISTURE/INSTABILITY PRESENT OUT AHEAD OF IT. IF THE ECMWF WERE TO VERIFY...THEN PRIMARILY SHOWERS WOULD BE OBSERVED. IN CONTRAST...THE GFS SEEMS TO BE MORE AGGRESSIVE WITH DEWPOINTS AND IF THIS WERE TO OCCUR...THEN THUNDERSTORMS COULD BE PRESENT OUT AHEAD OF THIS SYSTEM. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * LAKE EFFECT CIGS BECMG MVFR INTO EARLY AFTERNOON...INITIALLY MAY BE BRIEFLY BELOW 2 KFT...BUT SHOULD QUICKLY LIFT TO 2-2.5 KFT. * NORTHEAST WINDS BECOMG GUSTY TO G15KT BY LATE MORNING. * SMALL CHANCE FOR MVFR CIGS TONIGHT AND EARLY MONDAY MORNING. KREIN //DISCUSSION...UPDATED 12Z... THE TERMINALS LIE BETWEEEN A COLD FRONT TO THE SOUTH WHICH PASSED LATE YESTERDAY AND HIGH PRESSURE ACROSS ONTARIO AND QUEBEC. THE GRADIENT BETWEEN THESE FEATURES WILL CONTINUE TO FAVOR A NORTHEAST SYNOPTIC WIND. INITIALLY...THROUGH 14Z...A SLIGHTLY MORE NNW WIND WILL BE SEEN ACROSS NORTHEAST IL DUE TO A REMNANT LAND BREEZE FROM THE NIGHT. THIS IS AIDING CONVERGENCE INTO NORTHEAST IL THAT SHOULD HELP TO FOCUS DEVELOPING CLOUDS OVER THE LAKE INTO NORTHEAST IL BY MID MORNING...AND LIKELY TOWARD GYY AS WELL. THESE LAKE ENHANCED CLOUDS ARE PRESENTLY FAVORED TO BE AT OR ABOVE 2000 FT BY THE TIME THEY ARRIVE AT THE TERMINALS...BUT AT ONSET SOME COULD BE BELOW 2000 FT. THAT SHOULD BE BRIEF IF THAT OCCURS. CLOUDS SHOULD GRADUALLY BECOME MORE SCATTERED THROUGH THE AFTERNOON AS THE COLD AIR ADVECTION COMPONENT OVER THE WATER WEAKENS. THE HIGH PRESSURE WILL SETTLE SOUTHWARD OVER THE AREA THIS EVENING...WITH RETURN FLOW DEVELOPING ON MONDAY. //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN BROKEN CLOUDS BETWEEN 2000 AND 3500 FT. MEDIUM CONFIDENCE IN TIMING. LOW CONFIDENCE IN ANY CIGS BELOW 2000 FT. * HIGH CONFIDENCE IN WIND DIRECTIONAL TRENDS. MEDIUM CONFIDENCE IN GUSTS. * LOW CONFIDENCE IN ANY RETURNING BROKEN CIGS TONIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...CHC FOR MVFR. TUESDAY...SMALL CHC FOR MORNING VFR. WEDNESDAY...VFR. THURSDAY...CHC OF SHRA AND MVFR. FRIDAY...WINDY. CHC OF SHRA AND MVFR SATURDAY...VFR. MTF && .MARINE... 224 AM CDT BEHIND A COOL FRONT WHICH PASSED LATE ON SATURDAY...NORTHEAST FLOW WILL CONTINUE ACROSS THE LAKE TODAY. THIS WILL BE DIRECTED INTO THE NEARSHORE AREAS OF ILLINOIS AND INDIANA...FAVORING HIGH WAVES INTO THE AFTERNOON AND EVENING. HIGH PRESSURE WILL SLIDE SOUTHWARD OVER THE LAKE TONIGHT INTO EARLY MONDAY EASING WINDS. A WEAK COOL FRONT WILL PASS FROM WEST TO EAST OVER THE LAKE ON MONDAY NIGHT...OFFERING A WIND SHIFT BUT NO REAL INCREASE IN SPEED. THAT IS IN PART BECAUSE LOW PRESSURE WILL BE MOVING NORTHEASTWARD FROM THE LOWER OHIO VALLEY TO HUDSON BAY TUESDAY INTO WEDNESDAY SLOWING THE AFOREMENTIONED BOUNDARY. A POTENTIALLY ACTIVE END OF THE WEEK OVER THE WESTERN GREAT LAKES MAY BE IN STORE AS SEVERAL FORECAST MODELS INDICATE A STRONG LOW PRESSURE SOMEWHERE IN THE UPPER MIDWEST/GREAT LAKES REGION...WITH STRONG THERMAL ADVECTION CONDUCIVE FOR GUSTY WINDS AHEAD AND BEHIND OF THE LOW PRESSURE. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014 UNTIL 4 AM MONDAY. IN...HIGH RIP CURRENT RISK...INZ001-INZ002 UNTIL 4 AM MONDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
406 PM CDT SUN SEP 30 2012 ...CORRECTED THE LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1212 PM CDT SUN SEP 30 2012 AT 12Z SUNDAY AN UPPER LEVEL JET STREAK EXTENDED FROM NORTHWEST MONTANA INTO SOUTHERN BRITISH COLUMBIA. AT THE 500MB LEVEL A -14 TO -15C THERMAL TROUGH EXTENDED FROM NORTH DAKOTA INTO SOUTHWEST NEBRASKA. ANOTHER COLDER UPPER LEVEL THERMAL TROUGH WAS LOCATED NEAR THE LEFT EXIT REGION THE UPPER LEVEL JET LOCATED NEAR SOUTHERN SASKATCHEWAN AND SOUTHERN ALBERTA CANADA. AT THE 700MB LEVEL A +5 TO +7C THERMAL RIDGE EXTENDED FROM SOUTHERN SOUTH DAKOTA INTO NORTHEAST COLORADO WITH SOME 700-600MB MOISTURE AND MID LEVEL INSTABILITY PRESENT IN THIS AREA BASED ON THE NORTH PLATTE SOUNDING AND RAP. MOSAIC RADAR LOOP ALSO PICKED UP ON A FEW ISOLATED SHOWERS AND THUNDERSTORMS IN THIS AREA. NEAR THE SURFACE A TROUGH OF LOW PRESSURE STRETCHED FROM CENTRAL NEBRASKA INTO WEST CENTRAL KANSAS WITH A WEDGE OF HIGHER MOISTURE PRESENT AHEAD OF THIS TROUGH BASED THE EARLY MORNING STATUS/FOG, LOW TO MID 50S SURFACE DEWPOINTS, AND +10 TO +12C 850MB DEWPOINTS. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 143 PM CDT SUN SEP 30 2012 LATEST RAP WAS CONSISTENT WITH THE 12Z NAM AND THEY BOTH VERIFIED FAIRLY WELL WITH THE LOCATION OF THE SURFACE LEE TROUGH WHICH WAS LOCATED ACROSS FAR WESTERN KANSAS. AHEAD OF THIS SURFACE BOUNDARY A 0-1KM THTA-E RIDGE AXIS EXTENDED NORTHWARD INTO SOUTHWEST NEBRASKA. THIS FEATURE IS FORECAST TO MOVE VERY LITTLE THROUGH EARLY TONIGHT AND WILL BE THE AREA WHERE THE BETTER LOW LEVEL FORCING WILL BE LATE TODAY AS 500MB TEMPERATURE COOL AND INSTABILITY IMPROVES. WILL THEREFORE RETAIN MENTION OF LATE DAY/EARLY NIGHT THUNDERSTORMS ACROSS MAINLY SOUTHWEST AND NORTH CENTRAL KANSAS. THE UPPER LEVEL JET LOCATED OVER MONTANA EARLIER TODAY WILL DIVE SOUTH ALONG THE WESTERN HIGH PLAINS AND BY EARLY MONDAY THE LEFT EXIT REGION OF THIS JET IS FORECAST TO BE LOCATED OVER WESTERN KANSAS. BUFR SOUNDINGS ALSO SUGGESTING MOISTURE WILL BE PRESENT AROUND THE 700MB LEVEL EARLY IN THE DAY AS A COLD FRONT MOVES SOUTH ACROSS SOUTHWEST KANSAS. BASED ON THE LOCATION OF THE UPPER JET, BETTER 700MB MOISTURE ALONG WITH SOME FRONTOGENESIS WILL RETAIN MENTION OF PRECIPITATION EARLY IN THE DAY. BUFR SOUNDING WIND PROFILES INDICATED 30KTS AT 800MB LEVEL BEHIND THIS FRONT WITH MEAN MIXED LEVEL WINDS SUGGESTING WINDS SPEEDS IN THE 20 TO 30 MPH RANGE WILL BE POSSIBLE. 850MB TEMPERATURES AT 00Z TUESDAY SUGGESTS HIGHS WILL BE IN THE LOW TO MID 70S WHICH WERE SIMILAR TO THE MOSGUIDE, AND CONSMOS. THIS ALSO ONLY A FEW DEGREES COOLER THAN THE PREVIOUS FORECAST SO GIVEN A SLIGHT SUPER NEAR THE SURFACE THE PREVIOUS FORECAST WITH HIGHS MAINLY IN THE 75 TO NEAR 80 DEGREE RANGE STILL APPEARS ON TRACK. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 401 PM CDT SUN SEP 30 2012 NORTHERLY UPPER-LEVEL FLOW WILL PERSIST TUESDAY ON THE BACK SIDE OF AN UPPER LOW. IN THE ABSENCE OF LEE TROUGHING, PLEASANT WEATHER CAN BE EXPECTED. IT WILL BE FAIRLY COOL IN THE LOWER 40S IN THE MORNING GIVEN THE DRY AIR AND LIGHT WINDS. THE AFTERNOON WILL TURN OUT PLEASANT WITH HIGHS IN THE LOWER TO MID 70S AND LIGHT WINDS. A STRONG SHORTWAVE TROUGH WILL PROGRESS SOUTHEASTWARD OUT OF CANADA INTO THE NORTHERN PLAINS BY WEDNESDAY. AHEAD OF THE ASSOCIATED COLD FRONT, TEMPERATURES SHOULD REACH INTO THE UPPER 70S IN PLACES LIKE SCOTT CITY AND DIGHTON, WITH WARMER 80S FROM DODGE CITY INTO SOUTH CENTRAL KANSAS. SOME MID-LEVEL MOISTURE WILL ACCOMPANY THIS SYSTEM AFTER THE LOW-LEVEL BAROCLINIC ZONE MOVES THROUGH AND THE JET STREAK APPROACHES. SO A FEW RAIN SHOWERS CANNOT BE RULED OUT WEDNESDAY NIGHT, ESPECIALLY FROM DODGE CITY NORTHWARD TO THE INTERSTATE 70 CORRIDOR. THERE ARE MAJOR DISAGREEMENTS AMONG THE VARIOUS MODELS BY THURSDAY AND THROUGH THE WEEKEND. THE ECMWF DEVELOPS A POSITIVELY TILTED UPPER-LEVEL TROUGH FROM WINNIPEG SOUTHWESTWARD TO THE CALIFORNIA COAST, WHILE THE GFS DEVELOPS A LARGE TROUGH OVER THE GREAT LAKES REGION, WITH A CUTOFF LOW OFF OF THE WEST COAST. INTERESTINGLY, EVEN THOUGH THE PATTERNS ARE DIFFERENT IN THE GFS/ECMWF, THEY BOTH SHOW MID-LEVEL FRONTOGENESIS AND SOME POSSIBLE LIGHT RAIN FOR FRIDAY NIGHT. OTHER THAN THAT, BOTH MODELS SHOW SURFACE HIGH PRESSURE ENTRENCHED ACROSS THE PLAINS WITH FAIRLY COOL HIGHS MAINLY IN THE LOWER TO MID 60S FOR THURSDAY AND FRIDAY AND LOWS DROPPING INTO THE 40S. BY SATURDAY AND SUNDAY, THE GFS KEEPS A NORTHWESTERLY UPPER-LEVEL FLOW REGIME OVER THE PLAINS AS UPPER TROUGHING PERSISTS OVER THE GREAT LAKES. THIS WOULD BE A COOL AND MAINLY DRY REGIME. THE ECMWF INDICATES ISENTROPIC LIFT AS LOW LEVEL COOL AIR BECOMES WEDGED UNDERNEATH THE WEST- SOUTHWESTERLY MID-LEVEL FLOW. THIS WOULD YIELD A CLOUDY PATTERN WITH PERHAPS SOME AREAS OF LIGHT RAIN SATURDAY AND SUNDAY, AND POSSIBLY EVEN SNOW BY SUNDAY NIGHT. THE UKMET IS SIMILAR TO THE ECMWF AT DAY 6 WHILE THE GEM AGREES MORE WITH THE GFS. DUE TO THE GREAT UNCERTAINTY, WE JUST OPTED TO GO WITH THE ALLBLEND INITIALIZATION, WHICH FEATURES COOL BUT DRY WEATHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1212 PM CDT SUN SEP 30 2012 SCATTERED CONVECTION WILL BE POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING UNDER A -14 TO -15C 500MB THERMAL TROUGH AS IT MOVES ACROSS WESTERN KANSAS. BASED ON THE LOCATION OF THE THTA-E RIDGE AXIS AHEAD OF THE SURFACE BOUNDARY AND TIMING OF THE UPPER LEVEL TROUGH BY THE NAM/RAP WILL FOCUS ANY THUNDERSTORM CHANCES PRIOR TO 00Z AT GCK AND HYS. AT DDC THE CONVECTION SHOULD HOLD OFF UNTIL AFTER 21Z WITH A VCTS THROUGH 03Z. BUFR SOUNDINGS INDICATING CIGS WILL BE AT OR ABOVE 3000FT SO VFR CONDITIONS ARE EXPECTED. ALTHOUGH COULD SEE SOME GUSTY WINDS NEAR THESE ISOLATED THUNDERSTORMS LATER TODAY THE AVERAGE WIND SPEED IS EXPECTED TO BE AT 10KTS OR LESS. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 76 40 74 / 30 20 0 0 GCK 52 75 41 75 / 40 20 0 0 EHA 52 75 42 76 / 60 20 0 0 LBL 52 76 42 75 / 60 20 0 0 HYS 52 76 41 74 / 20 20 0 0 P28 53 80 46 74 / 10 20 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...FINCH AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
400 PM CDT SUN SEP 30 2012 ...UPDATED FOR LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1212 PM CDT SUN SEP 30 2012 AT 12Z SUNDAY AN UPPER LEVEL JET STREAK EXTENDED FROM NORTHWEST MONTANA INTO SOUTHERN BRITISH COLUMBIA. AT THE 500MB LEVEL A -14 TO -15C THERMAL TROUGH EXTENDED FROM NORTH DAKOTA INTO SOUTHWEST NEBRASKA. ANOTHER COLDER UPPER LEVEL THERMAL TROUGH WAS LOCATED NEAR THE LEFT EXIT REGION THE UPPER LEVEL JET LOCATED NEAR SOUTHERN SASKATCHEWAN AND SOUTHERN ALBERTA CANADA. AT THE 700MB LEVEL A +5 TO +7C THERMAL RIDGE EXTENDED FROM SOUTHERN SOUTH DAKOTA INTO NORTHEAST COLORADO WITH SOME 700-600MB MOISTURE AND MID LEVEL INSTABILITY PRESENT IN THIS AREA BASED ON THE NORTH PLATTE SOUNDING AND RAP. MOSAIC RADAR LOOP ALSO PICKED UP ON A FEW ISOLATED SHOWERS AND THUNDERSTORMS IN THIS AREA. NEAR THE SURFACE A TROUGH OF LOW PRESSURE STRETCHED FROM CENTRAL NEBRASKA INTO WEST CENTRAL KANSAS WITH A WEDGE OF HIGHER MOISTURE PRESENT AHEAD OF THIS TROUGH BASED THE EARLY MORNING STATUS/FOG, LOW TO MID 50S SURFACE DEWPOINTS, AND +10 TO +12C 850MB DEWPOINTS. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 143 PM CDT SUN SEP 30 2012 LATEST RAP WAS CONSISTENT WITH THE 12Z NAM AND THEY BOTH VERIFIED FAIRLY WELL WITH THE LOCATION OF THE SURFACE LEE TROUGH WHICH WAS LOCATED ACROSS FAR WESTERN KANSAS. AHEAD OF THIS SURFACE BOUNDARY A 0-1KM THTA-E RIDGE AXIS EXTENDED NORTHWARD INTO SOUTHWEST NEBRASKA. THIS FEATURE IS FORECAST TO MOVE VERY LITTLE THROUGH EARLY TONIGHT AND WILL BE THE AREA WHERE THE BETTER LOW LEVEL FORCING WILL BE LATE TODAY AS 500MB TEMPERATURE COOL AND INSTABILITY IMPROVES. WILL THEREFORE RETAIN MENTION OF LATE DAY/EARLY NIGHT THUNDERSTORMS ACROSS MAINLY SOUTHWEST AND NORTH CENTRAL KANSAS. THE UPPER LEVEL JET LOCATED OVER MONTANA EARLIER TODAY WILL DIVE SOUTH ALONG THE WESTERN HIGH PLAINS AND BY EARLY MONDAY THE LEFT EXIT REGION OF THIS JET IS FORECAST TO BE LOCATED OVER WESTERN KANSAS. BUFR SOUNDINGS ALSO SUGGESTING MOISTURE WILL BE PRESENT AROUND THE 700MB LEVEL EARLY IN THE DAY AS A COLD FRONT MOVES SOUTH ACROSS SOUTHWEST KANSAS. BASED ON THE LOCATION OF THE UPPER JET, BETTER 700MB MOISTURE ALONG WITH SOME FRONTOGENESIS WILL RETAIN MENTION OF PRECIPITATION EARLY IN THE DAY. BUFR SOUNDING WIND PROFILES INDICATED 30KTS AT 800MB LEVEL BEHIND THIS FRONT WITH MEAN MIXED LEVEL WINDS SUGGESTING WINDS SPEEDS IN THE 20 TO 30 MPH RANGE WILL BE POSSIBLE. 850MB TEMPERATURES AT 00Z TUESDAY SUGGESTS HIGHS WILL BE IN THE LOW TO MID 70S WHICH WERE SIMILAR TO THE MOSGUIDE, AND CONSMOS. THIS ALSO ONLY A FEW DEGREES COOLER THAN THE PREVIOUS FORECAST SO GIVEN A SLIGHT SUPER NEAR THE SURFACE THE PREVIOUS FORECAST WITH HIGHS MAINLY IN THE 75 TO NEAR 80 DEGREE RANGE STILL APPEARS ON TRACK. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 351 PM CDT SUN SEP 30 2012 NORTHERLY UPPER-LEVEL FLOW WILL PERSIST TUESDAY ON THE BACK SIDE OF AN UPPER LOW. IN THE ABSENCE OF LEE TROUGHING, PLEASANT WEATHER CAN BE EXPECTED. IT WILL BE FAIRLY COOL IN THE LOWER 40S IN THE MORNING GIVEN THE DRY AIR AND LIGHT WINDS. THE AFTERNOON WILL TURN OUT PLEASANT WITH HIGHS IN THE LOWER TO MID 70S AND LIGHT WINDS. A STRONG SHORTWAVE TROUGH WILL PROGRESS SOUTHEASTWARD OUT OF CANADA INTO THE NORTHERN PLAINS BY WEDNESDAY. AHEAD OF THE ASSOCIATED COLD FRONT, TEMPERATURES SHOULD REACH INTO THE UPPER 70S IN PLACES LIKE SCOTT CITY AND DIGHTON, WITH WARMER 80S FROM DODGE CITY INTO SOUTH CENTRAL KANSAS. SOME MID-LEVEL MOISTURE WILL ACCOMPANY THIS SYSTEM AFTER THE LOW-LEVEL BAROCLINIC ZONE MOVES THROUGH AND THE JET STREAK APPROACHES. SO A FEW RAIN SHOWERS CANNOT BE RULED OUT WEDNESDAY NIGHT, ESPECIALLY FROM DODGE CITY NORTHWARD TO THE INTERSTATE 70 CORRIDOR. THERE ARE MAJOR DISAGREEMENTS AMONG THE VARIOUS MODELS BY THURSDAY AND THROUGH THE WEEKEND. THE ECMWF DEVELOPS A POSITIVELY TILTED UPPER-LEVEL TROUGH FROM WINNIPEG SOUTHWESTWARD TO THE CALIFORNIA COAST, WHILE THE GFS DEVELOPS A LARGE TROUGH OVER THE GREAT LAKES REGION, WITH A CUTOFF LOW OFF OF THE WEST COAST. INTERESTINGLY, EVEN THOUGH THE PATTERNS ARE DIFFERENT IN THE GFS/ECMWF, THEY BOTH SHOW MID-LEVEL FRONTOGENESIS AND SOME POSSIBLE LIGHT RAIN FOR FRIDAY NIGHT. OTHER THAN THAT, BOTH MODELS SHOW SURFACE HIGH PRESSURE ENTRENCHED ACROSS THE PLAINS WITH FAIRLY COOL HIGHS IN THE LOWER TO MID 60S FOR THURSDAY AND FRIDAY. BY SATURDAY AND SUNDAY, THE GFS KEEPS A NORTHWESTERLY UPPER-LEVEL FLOW REGIME OVER THE PLAINS AS UPPER TROUGHING PERSISTS OVER THE GREAT LAKES. THIS WOULD BE A COOL AND MAINLY DRY REGIME. THE ECMWF INDICATES ISENTROPIC LIFT AS LOW LEVEL COOL AIR BECOMES WEDGED UNDERNEATH THE WEST-SOUTHWESTERLY MID-LEVEL FLOW. THIS WOULD YIELD A CLOUDY PATTERN WITH PERHAPS SOME AREAS OF LIGHT RAIN SATURDAY AND SUNDAY, AND POSSIBLY EVEN SNOW BY SUNDAY NIGHT. THE UKMET IS SIMILAR TO THE ECMWF AT DAY 6 WHILE THE GEM AGREES MORE WITH THE GFS. DUE TO THE GREAT UNCERTAINTY, WE JUST OPTED TO GO WITH THE ALLBLEND INITIALIZATION, WHICH FEATURES COOL BUT DRY WEATHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1212 PM CDT SUN SEP 30 2012 SCATTERED CONVECTION WILL BE POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING UNDER A -14 TO -15C 500MB THERMAL TROUGH AS IT MOVES ACROSS WESTERN KANSAS. BASED ON THE LOCATION OF THE THTA-E RIDGE AXIS AHEAD OF THE SURFACE BOUNDARY AND TIMING OF THE UPPER LEVEL TROUGH BY THE NAM/RAP WILL FOCUS ANY THUNDERSTORM CHANCES PRIOR TO 00Z AT GCK AND HYS. AT DDC THE CONVECTION SHOULD HOLD OFF UNTIL AFTER 21Z WITH A VCTS THROUGH 03Z. BUFR SOUNDINGS INDICATING CIGS WILL BE AT OR ABOVE 3000FT SO VFR CONDITIONS ARE EXPECTED. ALTHOUGH COULD SEE SOME GUSTY WINDS NEAR THESE ISOLATED THUNDERSTORMS LATER TODAY THE AVERAGE WIND SPEED IS EXPECTED TO BE AT 10KTS OR LESS. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 76 40 74 / 20 20 0 0 GCK 52 75 41 75 / 30 20 0 0 EHA 52 75 42 76 / 40 20 0 0 LBL 52 76 42 75 / 30 20 0 0 HYS 52 76 41 74 / 20 20 0 0 P28 53 80 46 74 / 10 20 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...FINCH AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
148 PM CDT SUN SEP 30 2012 ...UPDATED SHORT TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1212 PM CDT SUN SEP 30 2012 AT 12Z SUNDAY AN UPPER LEVEL JET STREAK EXTENDED FROM NORTHWEST MONTANA INTO SOUTHERN BRITISH COLUMBIA. AT THE 500MB LEVEL A -14 TO -15C THERMAL TROUGH EXTENDED FROM NORTHERN DAKOTA INTO SOUTHWEST NEBRASKA. ANOTHER COLDER UPPER LEVEL THERMAL TROUGH WAS LOCATED NEAR THE LEFT EXIT REGION THE UPPER LEVEL JET LOCATED NEAR SOUTHERN SASKATCHEWAN AND SOUTHERN ALBERTA CANADA. AT THE 700MB LEVEL A +5 TO +7C THERMAL RIDGE EXTENDED FROM SOU TERN SOUTH DAKOTA INTO NORTHEAST COLORADO WITH SOME 700-600MB MOISTURE AND MID LEVEL INSTABILITY PRESENT IN THIS AREA BASED ON THE NORTH PLATTE SOUNDING AND RAP. MOSAIC RADAR LOOP ALSO PICKED UP ON A FEW ISOLATED SHOWERS AND THUNDERSTORMS IN THIS AREA. NEAR THE SURFACE A TROUGH OF LOW PRESSURE STRETCHED FROM CENTRAL NEBRASKA INTO WEST CENTRAL KANSAS WITH A WEDGE OF HIGHER MOISTURE PRESENT AHEAD OF THIS TROUGH BASED THE EARLY MORNING STATUS/FOG, LOW TO MID 50S SURFACE DEWPOINTS, AND +10 TO +12C 850MB DEWPOINTS. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 143 PM CDT SUN SEP 30 2012 LATEST RAP WAS CONSISTENT WITH THE 12Z NAM AND THEY BOTH VERIFIED FAIRLY WELL WITH THE LOCATION OF THE SURFACE LEE TROUGH WHICH WAS LOCATED ACROSS FAR WESTERN KANSAS. AHEAD OF THIS SURFACE BOUNDARY A 0-1KM THTA-E RIDGE AXIS EXTENDED NORTHWARD INTO SOUTHWEST NEBRASKA. THIS FEATURE IS FORECAST TO MOVE VERY LITTLE THROUGH EARLY TONIGHT AND WILL BE THE AREA WHERE THE BETTER LOW LEVEL FORCING WILL BE LATE TODAY AS 500MB TEMPERATURE COOL AND INSTABILITY IMPROVES. WILL THEREFORE RETAIN MENTION OF LATE DAY/EARLY NIGHT THUNDERSTORMS ACROSS MAINLY SOUTHWEST AND NORTH CENTRAL KANSAS. THE UPPER LEVEL JET LOCATED OVER MONTANA EARLIER TODAY WILL DIVE SOUTH ALONG THE WESTERN HIGH PLAINS AND BY EARLY MONDAY THE LEFT EXIT REGION OF THIS JET IS FORECAST TO BE LOCATED OVER WESTERN KANSAS. BUFR SOUNDINGS ALSO SUGGESTING MOISTURE WILL BE PRESENT AROUND THE 700MB LEVEL EARLY IN THE DAY AS A COLD FRONT MOVES SOUTH ACROSS SOUTHWEST KANSAS. BASED ON THE LOCATION OF THE UPPER JET, BETTER 700MB MOISTURE ALONG WITH SOME FRONTOGENESIS WILL RETAIN MENTION OF PRECIPITATION EARLY IN THE DAY. BUFR SOUNDING WIND PROFILES INDICATED 30KTS AT 800MB LEVEL BEHIND THIS FRONT WITH MEAN MIXED LEVEL WINDS SUGGESTING WINDS SPEEDS IN THE 20 TO 30 MPH RANGE WILL BE POSSIBLE. 850MB TEMPERATURES AT 00Z TUESDAY SUGGESTS HIGHS WILL BE IN THE LOW TO MID 70S WHICH WERE SIMILAR TO THE MOSGUIDE, AND CONSMOS. THIS ALSO ONLY A FEW DEGREES COOLER THAN THE PREVIOUS FORECAST SO GIVEN A SLIGHT SUPER NEAR THE SURFACE THE PREVIOUS FORECAST WITH HIGHS MAINLY IN THE 75 TO NEAR 80 DEGREE RANGE STILL APPEARS ON TRACK. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 327 AM CDT SUN SEP 30 2012 MONDAY INTO TUESDAY WILL SEE AN UPPER TROUGH POSITIONED FROM THE HUDSON BAY REGION OF CANADA INTO THE LOWER MISSISSIPPI RIVER VALLEY. AN 80-100 KNOT JET STREAK ON THE BACK SIDE OF THE TROUGH WILL NOSE INTO THE CENTRAL PLAINS MONDAY BEFORE THE CORE OF STRONGER JET WINDS ROTATE ONTO THE FRONT SIDE OF THE TROUGH AXIS BY EARLY TUESDAY. UPSTREAM FROM THIS TROUGH A HIGH AMPLITUDE RIDGE WILL EXIST OFF THE WEST COAST WHILE A POTENT WAVE AND ASSOCIATED 100 KNOT JET STREAK DIGS INTO THE PACIFIC NORTHWEST STATES. THIS WILL LEAVE THE CENTRAL PLAINS UNDER A PROGRESSIVE NORTHWEST FLOW REGIME WITH THE AFOREMENTIONED JET STREAK AND ASSOCIATED SHORTWAVE AIDING IN PUSHING A WEAK FRONT THROUGH WESTERN KANSAS MONDAY MORNING. FURTHER, THE LEFT EXIT REGION OF THIS JET WILL INTERACT WITH AN 800-700 HPA BAROCLINIC ZONE TO PRODUCE A MODEST BAND OF FRONTOGENESIS AND RESULTANT ASCENT OVER WESTERN AND CENTRAL KANSAS MONDAY MORNING TO EARLY AFTERNOON. EXPECT THIS FORCING WILL BE ENOUGH TO TRIGGER AT LEAST SOME ISOLATED TO SCATTERED SHOWERS THROUGH EARLY AFTERNOON ALTHOUGH PRECIPITATION AMOUNTS WILL BE LIGHT. OTHERWISE...GOOD SOLAR INSOLATION BY MID AFTERNOON ALONG WITH 850 HPA TEMPERATURES BETWEEN +14 TO +18C SHOULD SUPPORT HIGHS IN THE UPPER 70S TO LOWER 80S BOTH MONDAY AND TUESDAY. WEDNESDAY WILL BE A TRANSITION DAY AHEAD OF A MAJOR PATTERN CHANGE ANTICIPATED ON THURSDAY AS THE AFOREMENTIONED UPPER WAVE DIGS SOUTHEAST INTO THE PLAINS STATES. THIS WILL PUSH A POTENT COLD FRONT THROUGH WESTERN KANSAS WEDNESDAY NIGHT INTO THURSDAY MORNING WITH MUCH COLDER AIR EXPECTED BEHIND THE BOUNDARY. NONETHELESS...AHEAD OF THE FRONT MOST OF WEDNESDAY WILL BE WARM AND DRY AS THE APPROACHING WAVE AIDS IN DEEPENING THE LEE TROUGH OVER EASTERN COLORADO WHILE A SURFACE LOW TRACKS ACROSS THE DAKOTAS. THIS WILL ALLOW MODEST SOUTH TO SOUTHWEST WINDS AHEAD OF THE TROUGH AXIS KEEP 850 HPA TEMPERATURES AROUND 20C WITH HIGHS IN THE 80S EXPECTED. HOWEVER, STRONG COLD AIR ADVECTION BEHIND THE BOUNDARY WILL LOWER TEMPERATURES QUICKLY ON THURSDAY WITH 850 HPA TEMPS OF +5 TO +10C AND RESULTANT HIGHS IN THE 60S EXPECTED BY AFTERNOON. THE UPPER WAVE THEN EJECTS NORTHEAST INTO THE GREAT LAKES TO HUDSON BAY REGION ON FRIDAY WHILE A SECOND MORE POTENT WAVE DIGS INTO THE NORTHERN ROCKIES. THIS WILL INITIALLY STALL THE FIRST BOUNDARY OVER THE SOUTHERN PLAINS BY FRIDAY MORNING BEFORE A SECOND FRONT SURGES THROUGH THE REGION FRIDAY NIGHT. IN ADDITION...JET DYNAMICS ARE SHOWN TO INTERACT WITH A MID LEVEL BAROCLINIC ZONE TO PRODUCE AN AREA OF FRONTOGENESIS AND RESULTANT ASCENT ACROSS WESTERN KANSAS FRIDAY NIGHT INTO EARLY SATURDAY. THIS MAY RESULT IN A CHANCE FOR SOME LIGHT RAIN ALTHOUGH THE MAIN STORY WILL LIKELY BE COOLER TEMPERATURES WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND LOWS POSSIBLE IN THE 30S TO LOWER 40S EXPECTED NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1212 PM CDT SUN SEP 30 2012 SCATTERED CONVECTION WILL BE POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING UNDER A -14 TO -15C 500MB THERMAL TROUGH AS IT MOVES ACROSS WESTERN KANSAS. BASED ON THE LOCATION OF THE THTA-E RIDGE AXIS AHEAD OF THE SURFACE BOUNDARY AND TIMING OF THE UPPER LEVEL TROUGH BY THE NAM/RAP WILL FOCUS ANY THUNDERSTORM CHANCES PRIOR TO 00Z AT GCK AND HYS. AT DDC THE CONVECTION SHOULD HOLD OFF UNTIL AFTER 21Z WITH A VCTS THROUGH 03Z. BUFR SOUNDINGS INDICATING CIGS WILL BE AT OR ABOVE 3000FT SO VFR CONDITIONS ARE EXPECTED. ALTHOUGH COULD SEE SOME GUSTY WINDS NEAR THESE ISOLATED THUNDERSTORMS LATER TODAY THE AVERAGE WIND SPEED IS EXPECTED TO BE AT 10KTS OR LESS. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 77 45 78 / 30 20 0 0 GCK 52 77 44 79 / 30 20 0 0 EHA 52 77 47 80 / 20 20 0 0 LBL 52 78 45 78 / 30 20 0 0 HYS 52 77 44 78 / 30 20 0 0 P28 53 81 48 78 / 10 20 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...AJOHNSON AVIATION...BURGERT
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
537 PM EDT SUN SEP 30 2012 .SYNOPSIS... LOW PRESSURE OVER THE BAY OF FUNDY WILL LIFT NORTH THROUGH EASTERN QUEBEC TONIGHT AND MONDAY. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD OVER NEW ENGLAND MONDAY NIGHT AND WILL HOLD OVER THE AREA ON TUESDAY. A TROUGH OF LOW PRESSURE WILL SLOWLY MOVE NORTHWARD UP THE EAST COAST TUESDAY NIGHT AND WEDNESDAY. A COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY NIGHT AND WILL CROSS THE REGION ON THURSDAY. ANOTHER COLD FRONT WILL APPROACH FROM THE THE WEST ON FRIDAY AND WILL PUSH EAST THROUGH THE REGION FRIDAY NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON SATURDAY AND WILL HOLD OVER THE REGION ON SUNDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... UPDATE...WITH SFC LOW PRES NEARING THE COAST OF DOWNEAST ME WINDS ARE BEGINNING TO TURN MORE WLY ACROSS MUCH OF THE CWFA. WILL SEE THESE GRADUALLY INCREASE OVER THE WATERS...AND SCA IN PLACE LOOKS GOOD FOR TNGT. WILL ALSO SEE WLY WINDS HELP CLEAR OUT COASTAL AND ADJACENT INTERIOR PORTIONS OF SRN NH AND SWRN ME. DIURNALLY DRIVEN CONVECTION UNDER THE UPR LOW WILL CONTINUE TO MOVE NEWD THIS EVE. EXPECT A GRADUAL WEAKENING WITH LOSS OF DAYTIME HEATING...BUT HI RES MODELS SUGGEST THEY WILL HOLD TOGETHER LONG ENOUGH TO AFFECT PARTS OF THE FAR SRN CWFA. HAVE HELD ONTO CHC POP HERE LONGER THAN THE REST OF THE COAST FOR THIS REASON. A BLEND OF THE PREVIOUS FCST WITH LATEST HRRR POP FIELD LOOKED LIKE A GOOD APPROXIMATION FOR TIMING AND HAVE USED THIS THRU THE OVERNIGHT. PREVIOUS DISCUSSION...SURFACE LOW PRESSURE CONTINUES TO MOVE NORTHWARD AND INTO DOWNEAST MAINE AS OF LATE THIS SUNDAY AFTERNOON. AS IT DOES SO...THE SHIELD OF STRATIFORM RAIN CONTINUES TO MOVE NORTHWARD AS WELL...WITH THE BACK EDGE ALONG A LINE FROM PORTLAND ME WESTWARD TO LITTLETON NH. THE STEADY RAINFALL WILL END WITH THE NORTHWARD PASSAGE OF THE BACK EDGE. HOWEVER...THE STRONG UPPER LOW IS STILL APPROACHING FROM THE WEST...SO SHOWERY PRECIPITATION IS DEVELOPING IN THE DRIER AREA TO THE SOUTHWEST. THEREFORE...HAVE NOT SCALED BACK ON POPS TOO MUCH IN THE SOUTH EARLY THIS EVENING. CANNOT RULE OUT AN ISOLD THUNDERSTORM ACROSS SOUTHERN NH TIL ABOUT 00Z...BUT DECIDED TO LEAVE OUT OF FORECAST AS PROBABILITY SEEMS LOW AT THIS TIME. AFTER DARK...THE SHOWERY PRECIP WILL WANE. THIS SHOULD LEAVE THE SOUTHERN ZONES AND COASTAL PLAIN MAINLY DRY OVERNIGHT. HOWEVER...DIDN/T GET RID OF POPS COMPLETELY...AS UPPER LOW IS STRONG ENOUGH TO INDUCE A FEW SHOWERS FROM TIME TO TIME. IT/S ALSO POSSIBLE THAT A LARGER AREA OF WRAP AROUND SHOWERS DEVELOPS LATE ALSO. ACROSS CENTRAL AND NORTHERN NH AND THE WESTERN ME MOUNTAINS...EXPECT NUMEROUS SHOWERS TO CONTINUE OVERNIGHT...WITH A GOOD CONTRIBUTION COMING FROM WESTERLY UPSLOPE. MIN TEMPS BASED ON A BLEND OF THE MET/MAV/NAM GUIDANCE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... STACKED LOW PRESSURE SYSTEM WILL LIKELY BE CENTERED OVER MAINE 8 AM MONDAY MORNING WITH WRAP AROUND SHOWERY PRECIP LIKELY OCCURRING OVER MUCH OF THE AREA. THE HIGHEST CONCENTRATION WILL BE OVER THE MOUNTAINS. CANNOT RULE OUT AN ISOLATED THUNDERSTORM WITH STEEP LAPSE RATES IN PLACE...BUT PROBABILITY IS A LITTLE TO LOW AT THIS TIME TO INCLUDE IN THE FORECAST. TIMING OF UPPER LOW PASSAGE IS JUST A LITTLE TOO QUICK WITH RESPECT TO DAYTIME HEATING AT THIS TIME. OTHERWISE...GRADUAL DRYING TAKES PLACE MONDAY AFTERNOON. UPSLOPE SHOWERS PROBABLY STILL OCCUR IN THE MOUNTAINS HOWEVER. CLEARING MONDAY NIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGH PRESSURE WILL PROVIDE MOSTLY SUNNY SKIES ON TUESDAY AS HIGH PRESSURE HOLDS OVER THE REGION. WILL LIKELY SEE SOME VARIABLE HIGH CLOUDINESS BUT IT SHOULD NOT HAVE MUCH AFFECT ON TEMPS WHICH WILL TOP OUT IN THE MID 60S TO NEAR 70 IN THE NORTH AND LOWER TO MID 70S IN THE SOUTH. SLOW MOVING AREA OF LOW PRESSURE OVER THE OHIO VALLEY WILL BRING INCREASING CLOUDS TO THE REGION TUESDAY NIGHT AND WEDNESDAY. INCREASINGLY MOIST ONSHORE FLOW WILL BRING OCEAN STRATUS INTO SOUTHERN NEW ENGLAND DURING THE DAY TUESDAY AND THIS WILL GRADUALLY LIFT NORTHWARD TUESDAY NIGHT AND WEDNESDAY. THIS WILL KEEP TEMPS UP TUESDAY NIGHT BUT WILL HOLD READINGS DOWN ON WEDNESDAY...ESPECIALLY IN SOUTHERN ZONES. IN ADDITION WILL BE GOING WITH LOW CHANCE POPS FOR SCATTERED SHOWERS LATE TUESDAY NIGHT IN SOUTHWEST ZONES AND FOR THE ENTIRE FORECAST AREA ON WEDNESDAY...BUT NOT EXPECTING MUCH AS FORCING LIMITED AT BEST. MORE CLOUDS AND SHOWERS WEDNESDAY NIGHT AS A COLD FRONT MOVES IN FROM THE WEST. SHOWERS ASSOCIATED WITH THIS SYSTEM WILL PUSH EAST OF THE FORECAST AREA AFTER MIDNIGHT BUT ABUNDANT LOW LEVEL MOISTURE WILL LINGER BEHIND THE FRONT AND IT WILL LIKELY TAKE MUCH OF THE DAY THURSDAY TO PRODUCE A FEW SUNNY BREAKS IN AREAS DOWNWIND OF THE MOUNTAINS. QUICK SHOT OF UPPER LEVEL RIDGING THURSDAY NIGHT AND FRIDAY BUT LOW LEVEL MOISTURE WILL AGAIN KEEP SKIES MOSTLY CLOUDY THURSDAY NIGHT INTO FRIDAY WITH SOME SUNNY BREAKS DEVELOPING MAINLY IN INLAND LOCATIONS FRIDAY AFTERNOON. COLD FRONT APPROACHING FROM THE WEST FRIDAY AFTERNOON WILL QUICKLY BLOW THROUGH THE REGION FRIDAY NIGHT WITH A BRIEF ROUND OF SHOWERS AND POSSIBLY A RUMBLE OF THUNDER. WILL SEE CLEARING SKIES DOWNWIND OF THE MOUNTAINS BY SATURDAY MORNING AS A WEAK SURFACE RIDGE BUILDS IN BEHIND THE FRONT. FAIR AMOUNT OF COLD AIR POISED TO THE NORTHWEST SATURDAY MORNING SO WILL LIKELY SEE DAYTIME HIGHS PEAK DURING THE LATE MORNING BEFORE DROPPING OFF IN THE AFTERNOON. HIGH PRESSURE WILL HOLD OVER THE REGION ON SUNDAY WITH TEMPS AVERAGING OUT BELOW NORMAL AFTER A CHILLY START TO THE DAY. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... SHORT TERM...OCCASIONAL MVFR TO IFR CONDITIONS IN SHOWERS AND PATCHY FOG AND LOW CLOUDS OVERNIGHT. HOWEVER...WE THINK THE TREND WILL BE TO IMPROVE AFTER MIDNIGHT. MVFR IN SHOWERS ON MONDAY IN THE MORNING...THEN IMPROVEMENT TO VFR IN THE AFTERNOON EXCEPT THE MOUNTAINS. LONG TERM...VFR TUESDAY. MVFR/IFR CEILINGS DEVELOPING LATE TUESDAY NIGHT AND WEDNESDAY AND PERSISTING THROUGH FRIDAY. && .MARINE... SHORT TERM...SCA FOR LATE TONIGHT AND MONDAY FOR THE OCEAN WATERS FOR G25KT AND SEAS AOA 5 FT. SEAS WILL TAKE A WHILE TO SUBSIDE...PROBABLY NOT UNTIL SOMETIME MONDAY NIGHT. LONG TERM...NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 8 PM EDT MONDAY FOR ANZ150-152-154. && $$ LEGRO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 PM EDT SUN SEP 30 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN SEP 30 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER THE ERN GREAT LAKES AND A RIDGE UPSTREAM FROM MN TO NEAR JAMES BAY. SINCE THE LOW HAS EDGED SLIGHTLY TO THE WEST...COOLER AIR AND AN INCREASE IN LOW LEVEL MOISTURE HAS ALSO PUSHED WESTWARD THROUGH UPPER MI WITH SOME PATCHY LOW CLOUDS...ESPECIALLY IN LOCATIONS FAVORED BY NE UPSLOPE FLOW. FARTHER UPSTREAM...A SHRTWV AND NOSE OF A 250-300 JET STREAK WAS MOVING THROUGH SRN ALBERTA. AT THE SFC...A RIDGE EXTENDED FROM NRN QUEBEC TO THE SOUTHWEST INTO THE NRN GREAT LAKES. TODAY...EXPECT ANY LINGERING LOWER CLOUDS TO THIN OUT BY MID TO LATE MORNING WITH INCREASING DAYTIME HEATING. OTHERWISE...HIGH PRES WILL CONTINUE TO DOMINATE THE REGION WITH MOSTLY SUNNY SKIES AND LIGHT ERLY WINDS. WITH LITTLE CHANGE IN THE POSITION OF THE 925-850 MB THERMAL TROUGH...TEMPS SHOULD BE SIMILAR TO SATURDAY WITH MAX READINGS IN THE MID TO UPPER 60S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. TONIGHT...THE SRN CANADA SHRTWV WILL MOVE THROUGH THE NRN PLAINS AND WILL HELP NUDGE THE BLOCKY DOWNSTREAM RIDGE/TROUGH TO THE EAST. HOWEVER...MDLS/ENSEMBLE CONSENSUS SUGGESTS THAT ANY PCPN WITH THE TROUGH SHOULD REMAIN WEST OF LAKE SUPERIOR. AN INCREASE IN SRLY WINDS AND SOME MID AND HIGH CLOUDS SHOULD KEEP TEMPS FROM FALLING OFF AS MUCH. LOOK FOR MIN READINGS FROM THE UPPER 30S TO AROUND 40 INLAND AND CLOSE TO 50 FOR THE GREAT LAKES AND WHERE DOWNSLOPE SSW FLOW PREVAILS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 510 AM EDT SUN SEP 30 2012 AT 12Z MON THERE WILL BE AN UPPER RIDGE OVER THE CWA...WITH A SHORTWAVE TROUGH FROM WRN HUDSON BAY TO WRN MN. AHEAD OF THE SHORTWAVE...A SFC TROUGH WILL BE OVER WRN LAKE SUPERIOR. MODELS NOT SHOWING MUCH MOISTURE WITH THE SYSTEM...OR MUCH QPF...BUT MOST DO SHOW SOME LIGHT PRECIP ASSOCIATED WITH A NARROW BAND OF LOW LEVEL MOISTURE OVER PORTIONS OF THE CWA AS THE SHORTWAVE PASSES MON INTO MON NIGHT. WILL KEEP SLIGHT CHANCE POPS IN THE FORECAST FOR THIS TIME. ATTENTION THEN TURNS TO A MUCH STRONGER SYSTEM THAT MODELS SHOW ENTERING THE NRN PLAINS TUE NIGHT AND STRENGTHENING SOMEWHERE IN THE REGION AROUND THE CWA THU. MODELS THEN SHOW REINFORCING UPPER ENERGY AND COLD AIR MOVING IN FRI INTO THE WEEKEND. OVERALL...THE FORECAST DURING THIS TIME IS VERY UNCERTAIN AND QUITE TRICKY. THERE IS SUBSTANTIAL RUN TO RUN VARIABILITY WITH MOST MODELS AS WELL AS MODEL DISAGREEMENT...SO FORECAST CONFIDENCE IS LOW. THE OVERALL IDEA SHOWN BY MODELS IS THAT THE UPPER TROUGH WILL DEEPEN AND CLOSE OFF SOMEWHERE IN THE REGION THU...AND THEN MOVE NE TO JAMES BAY OR QUEBEC FRI. NW LOW LEVEL WINDS AND 850MB TEMPS AS LOW AS -8C BEHIND THE SYSTEM WOULD BE FAVORABLE FOR LAKE EFFECT RAIN/SNOW FRI INTO SAT. MODELS HAVE BEEN SHOWING A GENERAL NORTHERLY TREND WITH THE LOW TRACK...MORE TOWARD THE ECMWF WHICH HAS SHOWN BETTER CONTINUITY. NOW THE LATEST RUN OF THE GFS (00Z/30) SLOWED THE EVOLUTION OF THE SYSTEM BY 12-18 HOURS FROM THE PREVIOUS RUN. WITH THE SYSTEM CURRENTLY S OF THE ALEUTIAN ISLANDS AT AROUND LAT 45N LON 160W IT IS NOT BEING SAMPLED BY TRADITIONAL UPPER AIR NETWORK...SO HOPEFULLY CONFIDENCE WILL BE IMPROVED WHEN THE SYSTEM MOVES INTO THE OBSERVATION NETWORK OF WRN CANADA AROUND 00Z TUE. IT IS IMPORTANT TO POINT THAT THERE IS A VERY WIDE GAMUT OF POSSIBLE REALITIES RESULTING FROM DIFFERENT PATHS THIS SYSTEM MAY TAKE. IF THE SYSTEM GOES MORE S OF THE CWA...SE TO NE GALES AND A WETTER/SNOWIER FORECAST MAY RESULT. IF THE SYSTEM GOES N OF THE CWA...W GALES AND A DRIER FORECAST MAY RESULT...WITH THE POSSIBILITY OF THUNDERSTORMS ALONG THE ATTENDANT COLD FRONT. IF THE SYSTEM GOES OVER THE CWA...A COMBINATION OF THE PREVIOUS SCENARIOS MAY RESULT. OF COURSE...THERE IS ALSO THE POSSIBILITY THAT THE SYSTEM ENDS UP BEING SIGNIFICANTLY WEAKER (OR EVEN STRONGER) THAN WHAT THE MODELS CURRENTLY SHOW. AM REALLY NOT CERTAIN WHAT WILL HAPPEN...BUT AM LEANING TOWARD THE NRN TRACK OF THE MORE PERSISTENT ECMWF AND FORECAST PERSISTENCE WITH THIS SYSTEM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 119 PM EDT SUN SEP 30 2012 EXPECT VFR CONDITIONS THIS FCST PERIOD AT ALL 3 TAF SITES WITH DRY HIGH PRESSURE DOMINATING. SOME MID AND HIGH CLOUDS WILL APPROACH WITH A SHORTWAVE LATE TONIGHT INTO MONDAY MORNING. COULD BE SOME LLWS AT KIWD LATE TONIGHT AND INCLUDED IN THE FORECAST WITH A WEAK SW LOW LEVEL JET. RAIN SHOULD HOLD OFF UNTIL AFTER THIS FORECAST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN SEP 30 2012 HIGH PRESSURE AND A WEAK PRESSURE GRADIENT WILL PERSIST TODAY. SRLY WINDS WILL INCREASE INTO THE 10 TO 20 KT RANGE TONIGHT AHEAD OF A TROUGH MOVING TOWARD THE REGION. WINDS WILL VEER TO THE WEST MONDAY AND THEN TO THE NORTH MONDAY NIGHT BUT SHOULD REMAIN AT OR BELOW 20 KT. HIGH PRESSURE WILL AGAIN DOMINATE TUESDAY WITH RELATIVELY LIGHT WINDS. A LOW PRESSURE SYSTEM LIFTING INTO NORTHWEST ONTARIO WILL PUSH A COLD FRONT THROUGH LAKE SUPERIOR THURSDAY WITH STRONG WRLY WINDS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
316 PM CDT SUN SEP 30 2012 .SHORT TERM...SFC HIGH HAD DRIFTED OVER NORTHERN LAKE SUPERIOR AS OF 20Z WITH DRY AIR ENTRENCHED OVER THE FA. SFC WIND WAS TURNING FROM THE SE TO THE S AHEAD OF AN APPROACHING A COLD FRONT. THIS FRONT IS EXPECTED TO MOVE THROUGH NORTHEAST MINNESOTA BY MIDNIGHT AND NW WI BY 12Z MONDAY. EXPECT THIS TO BE A DRY FROPA WHICH IS SUPPORTED BY FORECAST SOUNDINGS FROM ALL MODELS WHICH ARE DRY BELOW 10K FT. HAVE ADDED A MENTION OF PATCHY FOG TO THE NEAR SHORE WATERS FROM TWO HARBORS TO THE TWIN PORTS AND PORT WING WI AS WELL AS INLAND TO SUW WHICH THE LATEST HI RES MODELS HRRR AND NARRE AGREE ON THIS DEVELOPMENT. BEHIND THE FRONT LATER TONIGHT AND MONDAY A NW WIND IS EXPECTED AND IT WILL HELP USHER IN COOLER AIR. HOWEVER...WITH PLENTY OF SUN EXPECTED...LOOK FOR MAX TEMPS IN THE 60S TO NEAR 70 NEAR PBH AND BRD. THE SFC RIDGE AXIS OVERLAYS THE FA MONDAY NIGHT AND EXPECT RADIATIONAL COOLING WITH A CLEARING SKY TO PRODUCE MIN TEMPS IN THE 30S...TO AROUND 45 NEAR PBH. THE WARMER TEMPS NEAR PBH ARE DUE TO LINGERING CLOUDS. .LONG TERM...[TUESDAY - SATURDAY]... SNOW IS APPEARING MORE AND MORE LIKELY FOR LATER THIS WEEK. THE EXPECTED TREND IS FOR WARMER THAN NORMAL WEATHER ON TUESDAY AND WEDNESDAY TO COME TO AN END BY THURSDAY WHEN A LOW PRESSURE SYSTEM MOVES ACROSS SOUTHERN MINNESOTA AND NORTHERN WISCONSIN WEDNESDAY NIGHT AND THURSDAY. THE SYSTEM...WHICH THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH...WILL USHER IN RAIN AND MUCH COLDER WEATHER FOR THURSDAY. THE PCPN COULD TRANSITION TO SNOW OR A RAIN/SNOW MIXTURE THURSDAY NIGHT. PERIODS OF RAIN AND SNOW COULD CONTINUE INTO THE WEEKEND AS THE COLD WEATHER STICKS AROUND IN THE WAKE OF THE SYSTEM. IT IS UNCLEAR AT THIS POINT WHETHER THE SNOW WILL HAPPEN...BUT IT IS LOOKING MORE AND MORE LIKELY...ESPECIALLY FOR THURSDAY NIGHT AND FRIDAY NIGHT. DO NOT WANT TO MAKE ANY GUESSES ABOUT ACCUMULATION AT THIS POINT SINCE THE SYSTEM IS STILL FAR OUT. AT THIS POINT...DID NOT FORECAST ANY PERIODS OF PURE SNOW...BUT SOME PERIODS OF A RAIN/SNOW MIXTURE. && .AVIATION.../18Z TAF ISSUANCE/ VFR CONDITIONS WILL LIKELY CONTINUE ACROSS NE MINNESOTA AND NW WISCONSIN THROUGH MONDAY MORNING. THE LIGHT SOUTHERLY WINDS WILL SWITCH TO NORTHWESTERLY TONIGHT WITH THE PASSAGE OF A COLD FRONT...AND THE WINDS WILL INCREASE LATE TOMORROW MORNING. THERE MAY BE FOG SOUTH OF KDLH...BUT AT THIS TIME...DO NOT THINK IT WILL AFFECT THE TERMINAL. THERE MAY BE ISOLATED LIGHT RAIN SHOWERS TOMORROW MORNING NEAR KDLH AND KHIB. && .POINT TEMPS/POPS... DLH 45 65 39 63 / 10 10 0 0 INL 46 64 33 66 / 10 10 0 0 BRD 51 68 35 70 / 10 10 0 0 HYR 43 66 39 68 / 10 10 10 0 ASX 44 67 39 64 / 10 10 10 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GSF LONG TERM/AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
356 PM CDT SUN SEP 30 2012 .SHORT TERM...THROUGH LATE MONDAY AFTERNOON. THERE ARE TWO PRIMARY ISSUES AT HAND DURING THE NEXT 24 HOURS...THE FIRST BEING A POSSIBLE BUT STILL FAIRLY UNCERTAIN RISK FOR A FEW STRONG THUNDERSTORMS ACROSS THE FAR WESTERN CWA LATE THIS AFTERNOON INTO THIS EVENING...AND THE SECOND MAIN ISSUE BEING ELEVATED TO NEAR- CRITICAL FIRE DANGER ON MONDAY AFTERNOON. ALSO OF CONCERN IS TRYING TO FIGURE OUT HOW MUCH POST-FRONTAL RAIN WILL DEVELOP MAINLY DURING THE MORNING HOURS MONDAY. FOR ALL FIRE WEATHER DISCUSSION PLEASE SEE THE SEPARATE SECTION BELOW. 20Z OBJECTIVE SURFACE ANALYSIS INDICATES A NORTH-SOUTH TROUGH AXIS EXTENDING FROM NORTH CENTRAL NEB TO NORTHWEST KS...SEPARATING A LIGHT/VARIABLE TO LIGHT/SOUTHERLY WIND REGIME TO THE EAST FROM A STRONGER NORTHERLY COMPONENT TO THE WEST. WITHIN AND NEAR THE IMMEDIATE TROUGH AXIS...INCLUDING MAINLY THE WESTERN 1/4 OF THE CWA...SURFACE DEWPOINTS HAVE INCREASED TODAY BETWEEN THE MID 40S AND MID 50S...AND THERE ARE EVEN NOW SIGNS OF A LOW LEVEL CUMULUS FIELD STARTING TO SHOW ITS HAND. MEANWHILE...ACROSS THE MAJORITY OF THE CENTRAL/EASTERN CWA...DEWPOINTS HAVE AGAIN DONE THEIR SEEMINGLY DAILY CRASH WELL INTO THE 30S IN MOST AREAS...ONCE AGAIN BELOW FORECAST VALUES. ACTUAL HIGH TEMPS ARE WORKING OUT PRETTY WELL...WITH NEARLY ALL AREAS WITHIN A FEW DEGREES OF 80. OTHER THAN THE NEWLY DEVELOPED CUMULUS FIELD IN PARTS OF THE WEST...VISIBLE SATELLITE SHOWS THAT MOST OF THE THICKER HIGH CIRRUS FROM EARLIER TODAY HAS VACATED EAST OF THE CWA...WHILE A FEW LEGITIMATE SHOWERS/NEWLY DEVELOPED THUNDERSTORMS ARE ALREADY OCCURRING BOTH SOUTHWEST AND NORTHWEST OF THE CWA IN NORTH CENTRAL NEB AND NORTHWEST KS. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM MODEL DATA DEPICTS AN ALMOST DUE NORTHERLY MID LEVEL FLOW OVER THE CWA...WITH THE PRIMARY SYNOPTIC SCALE LOWS CONSISTING OF A DEEP CLOSED CIRCULATION OVER THE NORTHEAST STATES...A VERY SLOW MOVING CLOSED MID LEVEL LOW CENTERED OVER EASTERN OK...AND A PROGRESSIVE OPEN WAVE AND ASSOCIATED UPPER LEVEL JET STREAK DIPPING OUT OF SOUTHERN CANADA INTO THE MT/ND/SD REGION. STARTING WITH THE MOST IMMEDIATE ISSUE OVER THE NEXT 6 HOURS OR SO...HAVE MAINTAINED 20-30 PERCENT SHOWER/STORM CHANCES LATE THIS AFTERNOON INTO THIS EVENING FOR AREAS PRIMARILY WEST OF AN ORD- KEARNEY-PLAINVILLE LINE AND ESPECIALLY DAWSON...GOSPER AND FURNAS COUNTIES WHICH ARE ABOUT THE ONLY PARTS OF THE CWA WITHIN THE MOIST AXIS AND RESULTANT INSTABILITY AXIS...WITH 20Z MESOSCALE ANALYSIS SUGGESTING THAT A NARROW CORRIDOR OF MLCAPE AT LEAST INTO THE 500-1000 J/KG RANGE IS NOW IN PLACE IN THIS AREA. MEANWHILE...THE EASTERN HALF TO TWO THIRDS OF THE CWA HAS ESSENTIALLY NO CONVECTIVE INSTABILITY AT THIS HOUR...AND THIS WILL NOT CHANGE HEADING INTO THE EVENING HOURS. WITH DEEP LAYER 0-6KM BULK SHEAR ONLY AVERAGING AROUND 20 KT...AM NOT EXPECTING A LEGITIMATE SEVERE THREAT WITH THIS EVENT...BUT THERE IS MORE THAN ENOUGH INSTABILITY TO GET SOME SEMI-ORGANIZED MULTICELL STORMS OR A FEW QUASI-LINEAR CLUSTERS GOING...WITH SMALL HAIL AND WINDS TO AROUND 50 MPH VERY POSSIBLE. FOLLOWING THE REFLECTIVITY PROGS OF THE LATEST HRRR AND ALSO 12Z 4KM-WRF NMM...THERE COULD BE A DECENT LULL IN SHOWER/STORM ACTIVITY ONCE THE MID EVENING HOURS ARRIVE AND THE LOW LEVELS START TO STABILIZE A BIT. FOR THE LATE NIGHT 06Z-12Z POP/WEATHER GRIDS...OPTED TO BLANKET A 20 PERCENT CHANCE OF SHOWERS/ISOLATED THUNDER ACROSS ROUGHLY THE NORTHWEST 2/3 OF THE CWA INCLUDING THE TRI-CITIES...IN ASSOCIATION WITH INCREASING SYNOPTIC SCALE FORCING AND A RESULTANT SOUTHWEST-NORTHEAST BAND OF MID LEVEL SATURATION DEVELOPING AHEAD OF THE PARENT SHORTWAVE DROPPING SOUTHEAST ACROSS THE DAKOTAS. THERE ARE PLENTY OF QUESTIONS REGARDING HOW WIDESPREAD THIS LATE NIGHT PRECIPITATION MIGHT BE...WITH BOTH THE LATEST ECMWF/GFS SUGGESTING IT COULD BE NARROW BUT FAIRLY SOLID BAND OF MEASURABLE RAIN...WHILE THE NAM IS MUCH DRIER THROUGH SUNRISE ALONG WITH THE 4KM WRF-NMM. AT ANY RATE...NOT EXPECTING ANY LATE NIGHT STORMS TO BE ALL THAT STRONG LET ALONE SEVERE. KEPT LOW TEMPS TONIGHT SIMILAR TO PREVIOUS FORECAST AND MET/MAV GUIDANCE BLEND...GENERALLY RIGHT AROUND 50. FOR THE MONDAY DAYTIME HOURS...BY SUNRISE A WELL DEFINED SURFACE COLD FRONT WILL BE IN THE PROCESS OF CROSSING THROUGH THE CWA...AND REALLY THE MOST PROMINENT WEATHER FEATURE THROUGH THE DAY WILL BE THE QUITE BREEZY TO WINDY CONDITIONS IN ITS WAKE...AS NORTH WINDS AVERAGE 20-25 MPH SUSTAINED THROUGH MOST OF THE DAY AND GUSTS 30-35 MPH...BUT SHOULD AVERAGE AT LEAST 5 MPH SHORT OF ADVISORY CRITERIA. AS FOR PRECIP CHANCES DURING THE DAY...AM STARTING TO WONDER IF THE FORECAST 20 PERCENT CHANCE OF SHOWERS DURING THE MORNING HOURS ACROSS ROUGHLY THE SOUTHEAST 2/3 OF THE CWA IS HIGH ENOUGH...AS THE LATEST ECMWF/GFS ARE NOW SHOWING POTENTIAL FOR A MORE ORGANIZED NARROW BAND OF LIGHT BUT MEASURABLE RAINFALL PASSING THROUGH FROM NORTHWEST TO SOUTHEAST. HOWEVER...WITH MOST OF THE SATURATION ABOVE 700MB AM HESITANT TO GET TOO CARRIED AWAY WITH POPS...ESPECIALLY GIVEN THAT BOTH THE 18Z NAM AND 12Z WRF-NMM SHOW A MUCH MORE HIT AND MISS...LESS ORGANIZED BAND. STAYED WITH THE THEME FROM PREVIOUS FORECAST...AND LEFT THIS MORNING PRECIP RISK AS JUST SHOWERS WITH NO THUNDER MENTION...ALTHOUGH SUPPOSE A FEW ROGUE LIGHTNING STRIKES ARE NOT OUT OF THE QUESTION. ALSO IN LINE WITH PREVIOUS FORECAST...LEFT THE AFTERNOON 18Z-00Z PERIOD PRECIP FREE...BUT THERE A FEW HINTS IN LATEST MODELS THAT A FEW SHOWERS COULD LINGER INTO THE AFTERNOON PERIOD ACROSS THE FAR EASTERN/SOUTHERN CWA...AND THE NEXT SHIFTS WILL WANT TO SEE IF MAYBE THIS RAIN MENTION NEEDS EXTENDED IN TIME A BIT. BY THE MID AFTERNOON HOURS HOWEVER...CONFIDENCE IS FAIRLY HIGH THAT THE ENTIRE CWA SHOULD BE RAIN-FREE AND SEEING PLENTY OF SUN...AS THE PARENT MID LEVEL TROUGH AXIS AND RESULTANT MID LEVEL SATURATION STARTS TO FOCUS EAST OF THE AREA. TEMP WISE...LOWERED HIGHS 2-3 DEGREES FROM PREVIOUS IN MOST AREAS...FOLLOWING THE RAW 12Z NAM SOLUTION CLOSELY AND RANGING FROM LOW 70S NORTHWEST TO UPPER 70S SOUTHEAST. DID LOWER DEWPOINTS SEVERAL DEGREES ESPECIALLY DURING THE MID-LATE AFTERNOON WITH WIDESPREAD LOW-MID 30S AND EVEN UPPER 20S NORTHWEST. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY. SURFACE HIGH PRESSURE BUILDS SOUTH BEHIND THE COLD FRONTAL BOUNDARY...WITH RIDGE AXIS SETTLING ACROSS NEBRASKA AND WESTERN KANSAS MONDAY NIGHT. THE RIDGE DOES WEAKEN...HOWEVER IN THE COOLER...DRY AIRMASS WITH LIGHT WINDS AND GOOD RADIATIONAL CONDITIONS...WE ARE LOOKING AT THE POTENTIAL FOR SOME CHILLY OVERNIGHT LOW TEMPERATURES. SFC DPS DROP TO THE 20S AND LOWER 30S AND ITS LOOKING LIKE OVERNIGHT LOWS WILL AGAIN FALL INTO THE TEMPERATURE RANGE FAVORABLE FOR FROST...IN THE LOW/MID 30S. THESE LOCATIONS HAVE ALREADY EXPERIENCED SIMILAR LOW TEMPS THIS SEASON OR COLDER AND WILL NOT MENTION FROST...BUT WILL NEED TO MONITOR FOR FREEZE CONDITIONS FOR LOCATIONS THAT HAVE YET TO FREEZE. THE SURFACE RIDGE AXIS WASHES OUT/SHIFTS EAST ON TUESDAY WITH RETURN FLOW SETTING UP AHEAD OF A DEEPENING SURFACE LOW IN MANITOBA...ASSOCIATED WITH UPSTREAM TROUGH ALONG THE US/CANADIAN BORDER. SHORTWAVE RIDGING NOSES ONTO THE CENTRAL PLAINS IN BETWEEN UPPER LOW TO THE SOUTHEAST AND TROUGH ENTERING THE NORTHERN ROCKIES. TEMPERATURES WILL MODERATE TUESDAY...BUT WITH COOL START TO THE DAY AND LESS MIXING WILL AIM FOR HIGHS IN THE MID 70S VS NEAR 80F. WEDNESDAY IS REALLY ONE OF THE TRICKIER DAYS DUE TO TIMING OF COLD FRONTAL PASSAGE. UPPER LOW PRESSURE TROUGH REACHES THE NORTHERN PLAINS AND ROCKIES WITH THE ASSOCIATED COLD FRONT MOVING INTO WESTERN NEBRASKA BY 12Z WEDNESDAY. THERE ARE IMPRESSIVE PRESSURE RISES OF 10+MB PROGGED BEHIND THE FRONT IN THE NEB PANHANDLE. IN GENERAL MODELS HAVE TRENDED FASTER WITH FRONTAL PASSAGE WITH THE BOUNDARY THROUGH AT LEAST OUR WESTERN THIRD CWA...IF NOT HALF OF THE CWA BY 18Z. WITH THE FASTER TREND...HAVE SHARPENED TEMP GRADIENT NW/SE WITH AND LOWERED HIGHS IN OUR NORTHWEST TO THE LOW 70S. IF FRONT TRENDS ANY FASTER...COULD SEE TEMPS FALLING DURING THE AFTERNOON AND OUR NW ZONES MAY NOT REACH 70F. THIS BEING SAID...IF FRONT IS SLOWER AND MORE IN LINE WITH ECMWF VS NAM/GFS...TEMPS MAY BE WARMER THAN CURRENT FORECAST. PCPN CHCS INCREASE WEDNESDAY NIGHT IN INCREASING UPPER DYNAMICS AS TROUGH CROSSES THE CENTRAL PLAINS. THE 12Z GFS AND GEM ARE DEEPER WITH TROUGH THAN THE MORE PROGRESSIVE 00Z AND 12Z RUNS OF THE ECMWF. HAVE CONCERNS THAT ECMWF IS TOO PROGRESSIVE WITH SYSTEM...AND GFS/GFS ENSEMBLE LOOKS TO BE DECENT COMPROMISE BETWEEN ECMWF AND GEM SOLUTIONS. IF THE DEEPER TROUGH SOLUTIONS VERIFY WE COULD SEE A DECENT CHC FOR RAIN...BUT WOULD LIKE TO SEE MORE CONSISTENCY BEFORE RAISING POPS. THE TROUGH AXIS DEPARTS THURSDAY MORNING...WITH PCPN ENDING W/E. THEREAFTER FOR THE REMAINDER OF THE WORKWEEK AND INTO NEXT WEEKEND...PATTERN WILL BE INFLUENCED BY UPPER TROUGH ENCOMPASSING MUCH OF THE INTERIOR CONUS. TEMPERATURES WILL REMAIN BELOW NORMAL AND THERE WILL BE SOME HIT OR MISS CHCS FOR RAIN SHOWERS AS ENERGY TRANSLATES THRU FLOW. && .FIRE WEATHER...ALTHOUGH FIRE WEATHER CONDITIONS ARE CURRENTLY FORECAST TO FALL JUST A BIT SHORT OF CRITICAL THRESHOLDS ON MONDAY AFTERNOON THANKS TO RELATIVE HUMIDITY VALUES HOLDING AT LEAST SLIGHTLY ABOVE 20 PERCENT...THE CURRENTLY FORECAST COMBINATION OF SUSTAINED NORTHERLY WINDS AROUND 25 MPH/GUSTS 30-35 MPH AND RELATIVE HUMIDITY VALUES FALLING INTO THE 22-26 PERCENT RANGE FOR A FEW HOURS IS MORE THAN ENOUGH TO WARRANT THE CONTINUATION OF ELEVATED TO NEAR-CRITICAL FIRE DANGER WORDING IN THE HAZARDOUS WEATHER OUTLOOK. BASED ON RAINFALL TRENDS OVER THE PAST MONTH AND OFFICIAL FIRE GROWTH FUEL STATUS FROM FIRE MANAGERS...THE NEBRASKA COUNTIES WILL GENERALLY BE UNDER THE GUN MORE SO THAN KS. ONE FACTOR THAT MIGHT BE JUST ENOUGH TO SPARE US FROM DROPPING TO 20 PERCENT OR LOWER RELATIVE HUMIDITY IS THAT HIGH TEMPS WERE LOWERED 2-3 DEGREES FROM PREVIOUS FORECAST. HOWEVER...DEWPOINTS WERE ALSO DROPPED AT LEAST 5 DEGREES FROM PREVIOUS FORECAST IN MOST AREAS DURING THE KEY MID-LATE AFTERNOON HOURS...NOW ADVERTISED BETWEEN THE UPPER 20S AND MID 30S IN MOST COUNTIES. NEXT FEW SHIFTS WILL HAVE TO KEEP A CLOSE EYE ON THESE DEWPOINT/RH TRENDS...AS ONLY A SLIGHT DOWNWARD ADJUSTMENT COULD REQUIRE HEADLINE ISSUANCE FOR AT LEAST A SMALL PART OF MAINLY THE WESTERN CWA. LOOKING BEYOND MONDAY...WILL ALSO HAVE TO KEEP AN EYE ON WEDNESDAY AFTERNOON FOR OUR NEXT POTENTIALLY NEAR-CRITICAL FIRE DANGER SITUATION...AS NORTHERLY WINDS INCREASE AGAIN BEHIND THE NEXT COLD FRONT. && .PREV DISCUSSION... /ISSUED 1215 PM CDT SUN SEP 30 2012/ AVIATION...18Z KGRI TAF. VFR CEILING AND VISIBILITY ARE ANTICIPATED THROUGH THE NEXT 24 HOURS...WITH ANY CEILING LATER TONIGHT INTO MONDAY MORNING LIKELY AVERAGING ABOVE 10 THOUSAND FEET. AS A RESULT...THE MAIN CONCERN WILL BE THE PASSAGE OF A FAIRLY WELL-DEFINED COLD FRONT DURING THE LATTER HALF OF THE PERIOD. FOR THE REST OF TODAY INTO THIS EVENING...FAIRLY LIGHT SOUTHERLY BREEZES WILL PREVAIL WITH ANY THUNDERSTORM ACTIVITY LIKELY FOCUSING AT LEAST 60 MILES WEST OF KGRI. HAVE AIMED THE INITIAL SWITCH TO STEADY NORTHERLY BREEZES BEHIND THE COLD FRONT AT 10Z FOR NOW...WITH SPEEDS PICKING UP CONSIDERABLY AFTER SUNRISE WITH GUST POTENTIAL TO AT LEAST 27KT FOR THE LAST SEVERAL HOURS OF THE PERIOD. PRECIPITATION WISE...CONFIDENCE IS NOT HIGH IN THE TERMINAL SEEING AN ORGANIZED RISK OF SHOWERS OR WEAK STORMS...BUT DID INTRODUCE A VICINITY SHOWER MENTION DURING THE LAST 8 HOURS TO SUGGEST THE POSSIBILITY OF HIGH BASED ACTIVITY IN THE AREA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM/FIRE WEATHER/AVIATION...PFANNKUCH LONG TERM...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1215 PM CDT SUN SEP 30 2012 .UPDATE...RECENTLY SHIPPED AN UPDATE FOR THE AFTERNOON HOURS THROUGH 00Z. PRIMARY CHANGE FROM PREVIOUS FORECAST WAS TO DELAY ALL MENTION OF SHOWERS/STORMS UNTIL 21Z...AND EVEN THEN KEPT THESE 20-30 PERCENT CHANCES MAINLY WEST OF AN ORD-KEARNEY-PLAINVILLE LINE...WITH ESSENTIALLY ZERO RISK OF PRECIP FOR AREAS NEAR AND EAST OF HIGHWAY 281 THROUGH SUNSET. LATEST MODELS HAVEN/T CHANGED THE OVERALL THINKING MUCH...AS MID-LATE AFTERNOON STORM DEVELOPMENT IS STILL SLATED TO FOCUS VERY NEAR A ROUGHLY NORTH- SOUTH SURFACE TROUGH AXIS ALIGNED FROM NORTH CENTRAL NEB INTO NORTHWEST KS...WITH DAWSON...GOSPER AND FURNAS COUNTIES IN THE CWA MOST FAVORED TO SEE THIS CONVECTION. LATEST HOURLY MESOSCALE ANALYSIS IS ALREADY SUGGESTING AT LEAST 500 J/KG OF LOW LEVEL MIXED LAYER CAPE IS ALREADY POOLING JUST AHEAD OF THIS BOUNDARY ACROSS THE FAR WESTERN CWA...BUT LIKELY WITH ENOUGH CINH TO HOLD THE MAIN SHOW OFF FOR SEVERAL MORE HOURS. THAT BEING SAID...A SMALL...ROGUE STORM THAT FORMED AROUND SUNRISE HAS ALREADY BARELY SKIRTED WEST OF THE CWA THIS MORNING AS IT TRACKED FROM NORTH OF MCCOOK TO ITS CURRENT LOCATION SOUTH OF HILL CITY. STILL NOT THINKING MUCH SEVERE THREAT THIS AFTERNOON/EVENING WITH DEEP LAYER SHEAR ONLY AVERAGING AROUND 20KT...BUT SMALL HAIL TO DIME/PENNY SIZE AND WIND GUSTS TO AROUND 50 MPH GIVEN THE INVERTED-V LOOK TO SOUNDINGS ARE CERTAINLY FAIR GAME IF THINGS EVENTUALLY DO GET GOING. BECAUSE THERE ARE STILL QUESTIONS REGARDING HOW WIDESPREAD THIS STORM COVERAGE MIGHT BE...HAVE KEPT POPS CAPPED AT ONLY 30 PERCENT/SCATTERED COVERAGE FOR NOW. ANY INDIVIDUAL STORMS OR STORM CLUSTERS WILL DRIFT ALMOST DUE SOUTH AND SHOW VERY LITTLE IF ANY EASTWARD PROPAGATION. AS FOR AFTERNOON HIGH TEMPS...MADE LITTLE IF ANY CHANGE TO PREVIOUS FORECAST...WITH MOST ALL AREAS STILL LOOKING AT 79-82. && .AVIATION...18Z KGRI TAF. VFR CEILING AND VISIBILITY ARE ANTICIPATED THROUGH THE NEXT 24 HOURS...WITH ANY CEILING LATER TONIGHT INTO MONDAY MORNING LIKELY AVERAGING ABOVE 10 THOUSAND FEET. AS A RESULT...THE MAIN CONCERN WILL BE THE PASSAGE OF A FAIRLY WELL-DEFINED COLD FRONT DURING THE LATTER HALF OF THE PERIOD. FOR THE REST OF TODAY INTO THIS EVENING...FAIRLY LIGHT SOUTHERLY BREEZES WILL PREVAIL WITH ANY THUNDERSTORM ACTIVITY LIKELY FOCUSING AT LEAST 60 MILES WEST OF KGRI. HAVE AIMED THE INITIAL SWITCH TO STEADY NORTHERLY BREEZES BEHIND THE COLD FRONT AT 10Z FOR NOW...WITH SPEEDS PICKING UP CONSIDERABLY AFTER SUNRISE WITH GUST POTENTIAL TO AT LEAST 27KT FOR THE LAST SEVERAL HOURS OF THE PERIOD. PRECIPITATION WISE...CONFIDENCE IS NOT HIGH IN THE TERMINAL SEEING AN ORGANIZED RISK OF SHOWERS OR WEAK STORMS...BUT DID INTRODUCE A VICINITY SHOWER MENTION DURING THE LAST 8 HOURS TO SUGGEST THE POSSIBILITY OF HIGH BASED ACTIVITY IN THE AREA. && .PREV DISCUSSION... /ISSUED 406 AM CDT SUN SEP 30 2012/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT. MAIN FORECAST CONCERN IS ISOLATED THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON/EVENING... FOLLOWED BY THE PASSAGE OF A COLD FRONT SHORTLY THEREAFTER. WEAK SURFACE HIGH PRESSURE CENTERED NEAR HILL CITY KANSAS THIS MORNING HAS KEPT WINDS LIGHT...WITH ONLY SOME HIGH CLOUDS SCRAPING THE SOUTHEAST 1/3 OF THE FORECAST AREA. TEMPERATURES WARMER IN THE CLOUDY AREAS...AS OPPOSED TO CLOUD FREE REGIONS. ONE EARLY...ALTHOUGH MINOR CONCERN...MAY BE A BIT OF FOG IN THE FAR SOUTHWEST/WESTERN FORECAST AREA. LATEST HRRR DATA IS SHYING AWAY FROM ANY FOG OR LOW CLOUDS IN OUR FORECAST AREA...OPTING INSTEAD JUST TO THE WEST WHERE SOUTHERLY FLOW HAS ALLOWED FOR A LITTLE BETTER MOISTURE RETURN. MOST LIKELY THIS STUFF WOULDN/T GET GOING UNTIL CLOSE TO SUNRISE...SO ITS A GAME TIME DECISION WHETHER ITS WORTH EVEN BEING PART OF THE FORECAST. RIGHT NOW...ITS NOT LOOKING TO LIKELY TO FORM. THE MAIN STORY REST OF THE DAY IS WHETHER THE WESTERN PART OF THE FORECAST CAN SHARE IN SOME ISOLATED SHOWERS/THUNDERSTORMS LATE THIS AFTERNOON AND EVENING. WEAK SURFACE CONVERGENCE ALONG A BOUNDARY STARTS TO PUSHING THE FAR WESTERN SECTION OF THE FORECAST ABOUT MID AFTERNOON. THIS COINCIDES WITH NARROW AXIS OF MOISTURE AND SURFACE INSTABILITY BRIEFLY ABOVE 1000 J/KG. STEEP MID LEVEL LAPSE RATES ALSO SET UP. THERE LIKELY WILL BE SOME HIGH BASED SHOWERS/ISOLATED THUNDERSTORMS FORMING JUST TO THE WEST OF THE FORECAST AREA AROUND 3-4 PM...AND THEN GRADUALLY MIGRATE EAST. HAVE CONTINUED WITH THE 20-30% CHANCE OF RAIN...NOT SO MUCH FOR UNCERTAINTY ON CONVECTIVE ACTIVITY...BUT KEPT THINGS ON THE LOW SIDE WITH LARGE LOW LEVEL DEWPOINT DEPRESSIONS AND CLASSIC INVERTED V SOUNDINGS. BOTH SUGGEST LIMITED RAINFALL...BUT SOME WIND GUST POTENTIAL TO NEAR SEVERE LEVELS. HAVE INCLUDED SOME CHANCE INTO THE EARLY EVENING AS FAR EAST AS HIGHWAY 281...ALTHOUGH THAT MAY WELL BE STRETCHING IT WITH STORM MOTIONS PROBABLY AROUND 10KTS OR SO. LATEST MODELS HAVE FAVORED A LITTLE FURTHER WEST PROFILE...SO KEPT THE BEST SHOT FOR RAIN THERE. WELL...ONCE THAT STUFF WRAPS BY LATE EVENING...ATTENTION TURNS TO ONCOMING COLD FRONT LATE TONIGHT AND EARLY MONDAY. PRETTY STRONG PRESSURE RISES AS THE FRONT PASSES...SO EXPECT THE WIND TO PICK UP PRETTY STEADY BY LATE TONIGHT. GOOD MOMENTUM TRANSFER WILL CONTINUE ALL DAY MONDAY WITH NEARLY UNIDIRECTIONAL FLOW GIVING US THE FIRST BREEZY/WINDY DAY...SINCE THE LAST COLD FRONT A FEW DAYS AGO. MODELS TRY TO SQUEEZE OUT SOME LIGHT SHOWERS...PROBABLY SPRINKLES. NONE THE LESS...HAVE WORKED IN TANDEM WITH OTHER OFFICES TO INCLUDE A SLIGHT CHANCE OF LIGHT SHOWERS MONDAY MORNING...BEFORE SUNSHINE TAKES OVER LATER. TEMPERATURES WILL NOT ONLY FEEL COOLER DUE TO THE NORTH WIND...BUT ACTUALLY BE COOLER DURING THE DAY MONDAY. NOT MUCH ELSE TO WORRY ABOUT MONDAY NIGHT THROUGH TUESDAY NIGHT... WITH A COOL NIGHT MONDAY NIGHT...GIVING WAY TO A REALLY NICE AND MILD DAY TUESDAY WITH SUNSHINE AND LIGHT WINDS. LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. A COLD FRONT PROGGED TO TRANSITION THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY WILL PROVE TO BE THE MOST CHALLENGING ASPECT OF THE EXTENDED FORECAST. CHALLENGES WILL RESULT IN PRECIPITATION TIMING/COVERAGE AND TEMPERATURES BOTH AHEAD AND BEHIND THE COLD FRONT. PRECIP CHANCES WILL ALSO BE REALIZED TOWARDS THE END OF THE LONG TERM. A COLD FRONT WILL EXTEND DOWN INTO THE CENTRAL PLAINS ON THURSDAY FROM FROM AN ASSOCIATED UPPER LEVEL TROUGH FORECAST TO PASS THROUGH THE NORTHERN PLAINS. RETURN FLOW IN THE LOWER LEVELS AHEAD OF THIS FRONTAL BOUNDARY SHOULD ADVECT ENOUGH MOISTURE INTO THE CENTRAL PLAINS TO HELP AID IN THE DEVELOPMENT OF SOME STRATIFORM RAIN ACROSS THE OUTLOOK AREA. FORECAST SOUNDINGS SUGGEST A MOIST ATMOSPHERIC PROFILE BEGINNING AROUND MIDNIGHT ON WEDNESDAY AND CONTINUING THROUGH THE MORNING HOURS OF THURSDAY. PRECIPITATION TIMING WILL RELY SOLELY ON THE TIMING OF THE COLD FRONT...BUT CURRENT ANALYSIS LEADS TO PRECIP BEGINNING LATE WEDNESDAY NIGHT AND CONTINUING THROUGH THURSDAY MORNING BEHIND THE COLD FRONT. NO SEVERE WEATHER IS ANTICIPATED. THE BIGGEST CHANGE IN THE FORECAST WAS WEDNESDAY HIGH TEMPERATURES...WHICH WILL BE NEAR 80 DEGREES AHEAD OF THE FRONT FOR MOST OF THE OUTLOOK AREA. THIS CHANGE IS MAINLY DUE TO THE TIMING OF THE FRONT BEING A LITTLE SLOWER THAN PREVIOUSLY FORECAST. FURTHERMORE...850MB TEMPS ALSO SUGGEST HIGHER TEMPERATURES THAN THE OUTPUT FROM ALLBLEND. THURSDAY HIGH TEMPERATURES AND FRIDAY MORNING LOW TEMPERATURES HAVE BEEN RATHER TRICKY WITH THE PASSAGE OF THE FRONTAL BOUNDARY OVER THE LAST COUPLE OF DAYS. SEEMS AS THOUGH THE MODELS MAY HAVE FINALLY SETTLED ON A SOLUTION. THE PAST SEVERAL DAYS HAVE SHOWN A GENERAL DECREASE IN TEMPERATURES ACROSS THE CWA FOR THURSDAY HIGH TEMPERATURES AND THE OVERNIGHT LOWS...BUT TEMPERATURES ARE NOW NEARLY CONSISTENT WITH THE PREVIOUS FORECAST. THURSDAY WILL BE BELOW NORMAL FOR HIGHS AS UPPER 50S AND LOWER 60S ARE FORECAST. IN FACT...THE REST OF THE LONG TERM IS FORECAST TO EXPERIENCE BELOW NORMAL TEMPERATURES FOR THIS TIME OF YEAR. THURSDAY NIGHT LOW TEMPERATURES ARE STILL FLIRTING WITH FROST POTENTIAL. WILL NEED TO MONITOR THIS OVER THE NEXT COUPLE OF DAYS. A FROST ADVISORY MIGHT HAVE SOME CREDIBILITY ACROSS NORTHERN PARTS OF THE CWA NEXT WEEK. THERE WILL BE A CHANCE FOR PRECIPITATION FRIDAY NIGHT AND INTO SATURDAY AS ANOTHER CONVERGENCE ZONE SETS UP OVER THE CENTRAL PLAINS WITH FORECAST SOUNDINGS SUGGESTING A MOIST ATMOSPHERIC PROFILE. AGAIN...SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE/AVIATION...PFANNKUCH SHORT TERM...NOAA/NWS/MORITZ LONG TERM...GUERRERO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
348 PM EDT SUN SEP 30 2012 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL CROSS THE AREA TONIGHT WITH WIDESPREAD LIGHT TO MODERATE RAINFALL EXPECTED. THE RAIN TAPERS TO SHOWERS AND ENDS BY MONDAY EVENING AS HIGH PRESSURE BRIEFLY BUILDS INTO THE REGION. GENERALLY DRY AND MILDER WEATHER IS EXPECTED FOR TUESDAY...BEFORE THE THREAT OF SHOWERS INCREASES AGAIN BY MID WEEK WITH THE APPROACH OF THE NEXT LOW PRESSURE SYSTEM. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 300 PM EDT SUNDAY...COMPLEX FORECAST TAKING SHAPE FOR TONIGHT AS UPPER LEVEL LOW PRESSURE DRIFTS ATOP THE AREA WITH WIDESPREAD RAINFALL. HI-RES RAP/HRRR DATA HAS CAPTURED CURRENT SCENARIO OUT THROUGH THE NEXT 8 HOURS QUITE WELL AND WILL LEAN TOWARD ITS SOLN ACCORDINGLY. AS SOUTHERLY FLOW HAS BECOME ESTABLISHED EAST OF THE UPPER LOW CENTER TODAY...A DEEP WRN ATLANTIC/SUBTROPICAL MOISTURE PLUME AND ASSOCIATED RAFL HAS EVOLVED SSE-NNW ACROSS NEW ENGLAND...CAPTURED NICELY BY AMSU/SSM-I BLENDED TPW. THIS RAIN BAND WILL CONTINUE TO PIVOT BACK TO THE NORTH AND WEST OVER OUR CENTRAL AND NRN COUNTIES THIS EVENING INTO TONIGHT...EVOLVING INTO A PRIMARY DEFORMATION ZONE AS THE UPPER LOW CENTER EDGES EAST. NOT THE CLASSIC DEFORMATION SIGNATURE HOWEVER AS LOW LEVEL FLOW TRENDS WEST TO SOUTHWESTERLY AFTER MIDNIGHT AND PCPN SHIELD BEGINS TO TAKE ON A MORE OROGRAPHIC CHARACTER. NONETHELESS A WIDESPREAD RAINFALL EVENT STILL ON TRACK FOR MUCH OF OUR CENTRAL AND NORTHERN COUNTIES OVERNIGHT AND WILL CONTINUE CATEGORICAL POPS IN THESE AREAS. SOUTHERN COUNTIES WILL BE SLIGHTLY REMOVED AND JUST SOUTH OF THE PRIMARY RAIN BAND PIVOT POINT...AND WILL OFFER SLIGHTLY LOWER POPS IN THESE AREAS...BUT ALL LOCATIONS TO AT LEAST SEE A MEASUREABLE RAINFALL WITH HIGHEST AMOUNTS NORTH. LOWS AGAIN VERY UNIFORM GIVEN LIGHT WINDS AND LACK OF LOW LEVEL THERMAL ADVECTION...GENERALLY U40S TO L50S. PATCHY FOG ALSO A GOOD BET HERE AND THERE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM EDT SUNDAY...AS UPPER LOW DRIFTS NORTHEAST AND SLOWLY AWAY FROM THE REGION ON MONDAY...DEFORMATION/OROGRAPHICALLY FORCED PCPN SHIELD SHOULD SLOWLY ERODE/WEAKEN OVER TIME...WITH MOST AREAS OUTSIDE OF THE NORTHERN MTNS TRENDING DRY BY THE AFTERNOON HOURS. SOUTH TO SOUTHWESTERLY FLOW TO CONTINUE WITH CONDITIONS GUSTY AT TIMES BY AFTERNOON. HIGHS A TAD MILDER AS 925-850 THERMAL PROFILES GRADUALLY MODERATE...GENERALLY IN THE 58 TO 65 RANGE WITH MILDEST READINGS WEST. FAIR AND DRY WEATHER THEN RETURNS BY MONDAY NIGHT INTO MUCH OF TUESDAY AS SHORTWAVE RIDGING BUILDS INTO THE NORTHEAST FROM THE MID-ATLANTIC/OHIO VALLEY STATES. GENERALLY CLR TO PC CONDS EXPECTED WITH MILDER NEAR SEASONABLE TEMPERATURES EXPECTED. CLOUDS AND A LOWER END THREAT OF SHOWERS WILL BE ON THE INCREASE BY TUESDAY EVENING INTO TUESDAY NIGHT HOWEVER AS NEXT UPPER SHORTWAVE TROUGH OPENS UP AND LIFTS NORTHEAST OUT OF THE MISS/TENN VALLEY REGION. LATEST MODEL TRENDS HAVE SHIFTED CONSIDERABLY FURTHER WEST WITH THIS FEATURE ON THE 12Z MODEL SUITE HOWEVER...DEPICTING MILDER SOUTHERLY FLOW AND A MORE SCATTERED NATURE TO THE SHOWER ACTIVITY AS MEAN H5 BERMUDA RIDGING STRENGTHENS AND SHIFTS WEST TO NEAR 30N/-70W. WITH SUCH BROAD CONSENSUS...HARD TO IGNORE THIS POTENTIAL SHIFT IN THINKING...AND HAVE TRENDED POPS BACK SOMEWHAT INTO THE 30/40% RANGE ALONG WITH RAISING MIN TEMPS BY 2-4 DEG ACROSS THE BOARD. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 330 PM EDT SUNDAY...FCST FOCUS WL BE TIMING OF RAIN CHCS AND TEMPS IN ACTIVE SW FLW ALOFT FOR DAYS 4 THRU 7. MID/UPPER LVL RIDGE IN THE CENTRAL ATLANTIC WL RETROGRADE BACK WEST TWD THE EAST COAST BY MID WEEK...WHICH WL RESULT IN BUILDING HGHTS AND A BLOCKING TYPE PATTERN. THIS WL ALSO DEFLECT MID/UPPER LVL S/W ENERGY AND ASSOCIATED MOISTURE FROM THE MS VALLEY INTO THE GREAT LAKES AREA...WELL WEST OF OUR CWA...PLACING OUR REGION IN THE WARM SECTOR FOR WEDS/THURS. PROGGED 85H TEMPS WARM BTWN 12C AND 14C WITH 925MB TEMPS NEAR 10C...SUPPORT HIGHS WELL INTO THE 70S. HOWEVER...CLOUDS MAY LIMIT SFC HEATING SOME ACRS MTNS/NEK. GEM/ECMWF/GEM ALL SHOW GOOD 850 TO 500 MB RH MOVING ACRS OUR CWA...BUT BEST PVA ASSOCIATED WITH 5H VORT IS LOCATED TO OUR WEST...THEREFORE WL KEEP POPS BTWN 30 AND 50% ATTM. GIVEN THE PRIMARY STORM TRACK TO OUR WEST WOULD ANTICIPATE A HIGH POP LOW QPF EVENT FOR THIS SYSTEM. AN INCREASE IN HUMIDITY IS LIKLEY WITH DWPTS IN THE 50S TO NEAR 60F...WHICH WL KEEP OVERNIGHT LOWS MUCH ABOVE NORMAL FOR WEDS NIGHT AND THURS NIGHT. BY LATE WEEK INTO NEXT WEEKEND MID/UPPER LVL RIDGE SLOWLY BREAKS DOWN...AS SFC COLD FRNT APPROACHES FA. STILL SOME UNCERTAINTY TO TIMING OF SYSTEM AND IF SFC LOW PRES DEVELOPS ALONG THE FRNT. GIVEN THE LARGE BLOCKING PATTERN IN PLACE...WL TREND TWD THE SLOWER ECMWF TIMING OF SYSTEM...BUT MENTION SCHC TO LOW CHC POPS THRU THE PERIODS. LOOKS LIKE THE BEST CAA AND COOLER TEMPS ARRIVE ON SUNDAY INTO MONDAY...WITH VALUES BACK CLOSER TO NORMAL. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...DEEP CLOSED 5H/7H CYCLONIC CIRCULATION ACRS NORTHERN PA WL CONT TO ADVECT PLENTY OF MOISTURE ACRS OUR TAF SITES THRU TONIGHT. OVERALL IFR CONDITIONS WL CONT AT SLK/MSS WITH MAINLY IFR AT BTV/MPV/RUT...AND MVFR AT PBG THRU THIS AFTN/EVENING. VAD PROFILE SHOWS NORTHERLY FLW DOWN THE CPV...HELPING TO ENHANCE LLVL MOISTURE CONVERGENCE AT BTV WITH CRNT RADAR SHOWING A BAND OF MODERATE RAIN ROTATING INTO OUR NORTHERN/CENTRAL TAF SITES. OBS INDICATING IFR CONDITIONS WITH VIS BTWN 1-3SM AND CIGS BROKEN TO OVERCAST AT 400 TO 800 FT. THIS BAND OF RAIN WL SLOWLY LIFT FROM SE TO NW ACRS OUR TAF SITES THRU THE REST OF THIS AFTN. THIS EVENING...BOTH RAP AND NAM SHOW A WIND SHIFT TO THE SW BTWN 03Z AND 05Z...WHICH WL RESULT IN DOWNSLOPE FLW AND SOME IMPROVING CIGS AT BTV/PBG. WL MENTION MVFR CONDITIONS. OTHERWISE...ANTICIPATE MAINLY IFR CIGS TO CONT AT MPV/RUT/SLK/MPV WITH PATCHY DRIZZLE/FOG REDUCING VIS BTWN 1-3SM AT TIMES. BUFKIT VERTICAL MOISTURE PROFILES SHOW A SLOW DECREASE IN RH BTWN 13-15Z WITH BETTER MIXING...RESULTING IN MVFR CONDITIONS AT MOST SITES. SLOWEST SITES TO CLR WL BE SLK/MPV. OUTLOOK 18Z MONDAY THROUGH THURSDAY... WEAK SFC RIDGE WL RESULT IN DRYING ALOFT AND AT THE SFC WITH MAINLY VFR CONDITIONS AT BTV/MSS/RUT/PBG AND MVFR BECMG VFR AT MPV/SLK FROM 18Z THRU 18Z WEDS. SOME PATCHY FOG WL BE POSSIBLE AT SLK/MPV MONDAY NIGHT/TUES MORNING. NEXT SYSTEM ARRIVES WEDS AFTN INTO THURS WITH MORE SCATTERED SHOWERS AND POTENTIAL PERIODS OF MVFR CONDITIONS. && .HYDROLOGY... AS OF 300 PM EDT SUNDAY...WIDESPREAD RAINFALL EXPECTED THIS EVENING INTO TONIGHT WITH DEFORMATION/WRAP-AROUND PCPN AFFECTING THE REGION ASSOC WITH PASSG OF UPPER LOW PRESSURE. 24-HR BASIN TOTALS GENERALLY IN THE 0.50 TO 1.0 INCH RANGE ACROSS CENTRAL AND NORTHERN WATERSHEDS...AND 0.25 TO 0.50 INCH SOUTH. ONLY MODESTLY MOIST ANTECEDENT GROUND CONDITIONS AND ONLY SLIGHT TO MODEST RISES ON AREA RIVERS OF 1-2 FEET EXPECTED AS RUNOFF PEAKS BY MONDAY AFTERNOON. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...TABER AVIATION...TABER HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
300 PM EDT SUN SEP 30 2012 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL CROSS THE AREA TONIGHT WITH WIDESPREAD LIGHT TO MODERATE RAINFALL EXPECTED. THE RAIN TAPERS TO SHOWERS AND ENDS BY MONDAY EVENING AS HIGH PRESSURE BRIEFLY BUILDS INTO THE REGION. GENERALLY DRY AND MILDER WEATHER IS EXPECTED FOR TUESDAY...BEFORE THE THREAT OF SHOWERS INCREASES AGAIN BY MID WEEK WITH THE APPROACH OF THE NEXT LOW PRESSURE SYSTEM. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 300 PM EDT SUNDAY...COMPLEX FORECAST TAKING SHAPE FOR TONIGHT AS UPPER LEVEL LOW PRESSURE DRIFTS ATOP THE AREA WITH WIDESPREAD RAINFALL. HI-RES RAP/HRRR DATA HAS CAPTURED CURRENT SCENARIO OUT THROUGH THE NEXT 8 HOURS QUITE WELL AND WILL LEAN TOWARD ITS SOLN ACCORDINGLY. AS SOUTHERLY FLOW HAS BECOME ESTABLISHED EAST OF THE UPPER LOW CENTER TODAY...A DEEP WRN ATLANTIC/SUBTROPICAL MOISTURE PLUME AND ASSOCIATED RAFL HAS EVOLVED SSE-NNW ACROSS NEW ENGLAND...CAPTURED NICELY BY AMSU/SSM-I BLENDED TPW. THIS RAIN BAND WILL CONTINUE TO PIVOT BACK TO THE NORTH AND WEST OVER OUR CENTRAL AND NRN COUNTIES THIS EVENING INTO TONIGHT...EVOLVING INTO A PRIMARY DEFORMATION ZONE AS THE UPPER LOW CENTER EDGES EAST. NOT THE CLASSIC DEFORMATION SIGNATURE HOWEVER AS LOW LEVEL FLOW TRENDS WEST TO SOUTHWESTERLY AFTER MIDNIGHT AND PCPN SHIELD BEGINS TO TAKE ON A MORE OROGRAPHIC CHARACTER. NONETHELESS A WIDESPREAD RAINFALL EVENT STILL ON TRACK FOR MUCH OF OUR CENTRAL AND NORTHERN COUNTIES OVERNIGHT AND WILL CONTINUE CATEGORICAL POPS IN THESE AREAS. SOUTHERN COUNTIES WILL BE SLIGHTLY REMOVED AND JUST SOUTH OF THE PRIMARY RAIN BAND PIVOT POINT...AND WILL OFFER SLIGHTLY LOWER POPS IN THESE AREAS...BUT ALL LOCATIONS TO AT LEAST SEE A MEASUREABLE RAINFALL WITH HIGHEST AMOUNTS NORTH. LOWS AGAIN VERY UNIFORM GIVEN LIGHT WINDS AND LACK OF LOW LEVEL THERMAL ADVECTION...GENERALLY U40S TO L50S. PATCHY FOG ALSO A GOOD BET HERE AND THERE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM EDT SUNDAY...AS UPPER LOW DRIFTS NORTHEAST AND SLOWLY AWAY FROM THE REGION ON MONDAY...DEFORMATION/OROGRAPHICALLY FORCED PCPN SHIELD SHOULD SLOWLY ERODE/WEAKEN OVER TIME...WITH MOST AREAS OUTSIDE OF THE NORTHERN MTNS TRENDING DRY BY THE AFTERNOON HOURS. SOUTH TO SOUTHWESTERLY FLOW TO CONTINUE WITH CONDITIONS GUSTY AT TIMES BY AFTERNOON. HIGHS A TAD MILDER AS 925-850 THERMAL PROFILES GRADUALLY MODERATE...GENERALLY IN THE 58 TO 65 RANGE WITH MILDEST READINGS WEST. FAIR AND DRY WEATHER THEN RETURNS BY MONDAY NIGHT INTO MUCH OF TUESDAY AS SHORTWAVE RIDGING BUILDS INTO THE NORTHEAST FROM THE MID-ATLANTIC/OHIO VALLEY STATES. GENERALLY CLR TO PC CONDS EXPECTED WITH MILDER NEAR SEASONABLE TEMPERATURES EXPECTED. CLOUDS AND A LOWER END THREAT OF SHOWERS WILL BE ON THE INCREASE BY TUESDAY EVENING INTO TUESDAY NIGHT HOWEVER AS NEXT UPPER SHORTWAVE TROUGH OPENS UP AND LIFTS NORTHEAST OUT OF THE MISS/TENN VALLEY REGION. LATEST MODEL TRENDS HAVE SHIFTED CONSIDERABLY FURTHER WEST WITH THIS FEATURE ON THE 12Z MODEL SUITE HOWEVER...DEPICTING MILDER SOUTHERLY FLOW AND A MORE SCATTERED NATURE TO THE SHOWER ACTIVITY AS MEAN H5 BERMUDA RIDGING STRENGTHENS AND SHIFTS WEST TO NEAR 30N/-70W. WITH SUCH BROAD CONSENSUS...HARD TO IGNORE THIS POTENTIAL SHIFT IN THINKING...AND HAVE TRENDED POPS BACK SOMEWHAT INTO THE 30/40% RANGE ALONG WITH RAISING MIN TEMPS BY 2-4 DEG ACROSS THE BOARD. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 324 AM EDT SUNDAY...GOOD RUN-TO-RUN CONSISTENCY NOW SHOWN IN GFS SOLNS LAST SEVERAL CYCLES. GOOD CONSISTENCY WITH 00Z GFS ENSEMBLE AND 00Z ECMWF THROUGH THURSDAY BEFORE ECMWF DIVERGES SIGNIFICANTLY. CURRENT FCST GENERALLY FOLLOWS 00Z GFS. SRN STREAM 500MB TROUGH EXTENDING ACROSS THE MID/LWR MS RIVER VALLEY AT 00Z WEDNESDAY IS EXPECTED TO BE ASSOCIATED WITH A WEAK SFC LOW PRESSURE SYSTEM VCNTY OF THE UPR OHIO VLY/CENTRAL APPALACHIANS. EWD EXTENDING WARM FRONT EXPECTED TO LIFT NWD BRINGING INCREASING CLOUDS AND A CHANCE OF SHOWERS TO THE NORTH COUNTRY TUESDAY NIGHT. 850MB TEMPS PROGGED TO BE QUITE WARM (00Z GFS SHOWS +14C AT 850MB BY 12Z WED). WITH CLOUDS AND WAA SHOULD SEE LOWS GENERALLY IN THE 50S AREAWIDE. WEDNESDAY AND WEDNESDAY NIGHT...EXPECT TO SEE SRN STREAM SHORTWAVE TROUGH BEGIN TO SHEAR NEWD WITH WEAK SFC LOW PASSING WEST OF THE NORTH COUNTRY DURING THE DAY WEDNESDAY. CAN/T RULE OUT CONTINUED CHANCES OF SHOWERS WED/WED NIGHT WITH SKIES REMAINING MOSTLY CLOUDY. AIR MASS QUITE MILD SO HIGHS IN THE LOWER 70S APPEAR MOST LIKELY...WITH LOWS AGAIN IN THE 50S WED NIGHT. SOME CLEARING EXPECTED THURSDAY WITH DRIER CONDITIONS AS TROUGH DEPARTS. 850MB TEMPS COOL SLIGHTLY TO ABOUT +10C FOR THURSDAY SO STILL LOOKING AT HIGHS UPR 60S TO LWR 70S. DEEP-LAYER RIDGE BRIEFLY IN PLACE THU NGT INTO EARLY FRIDAY SO KEPT THAT PERIOD DRY. A COLD FRONT APPROACHES FROM THE GREAT LAKES FRIDAY AFTN WITH CHANCES FOR SHOWERS FRIDAY AFTN ACROSS NRN NY. PRECEDING AIR MASS STILL MILD WITH HIGHS UPR 60S TO LWR 70S LIKELY. SHOWERS AREAWIDE FRIDAY NIGHT ASSOCIATED WITH COLD FRONT. SATURDAY LOOKS COOLER WITH GUSTY WESTERLY WINDS POSSIBLE. MAY STILL SEE SOME ISOLD -SHRA WITH SHALLOW INSTABILITY...ESPECIALLY ACROSS THE HIGHER TERRAIN. HIGHS SATURDAY FORECAST AROUND 60 EXCEPT LOW-MID 50S FOR NRN NY. IT/S WORTH NOTING THAT THE 00Z ECMWF SHOWS A CONSIDERABLY SLOWER ARRIVAL OF THE COLD FRONT...SO IT/S POSSIBLE TEMPERATURES WILL BE WARMER THAN FORECAST SATURDAY WITH FRONTAL PASSAGE NOT UNTIL SATURDAY NIGHT. CURRENT FCST REFLECTS 00Z GFS AND 00Z GFS ENSEMBLE MEAN SOLNS. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...DEEP CLOSED 5H/7H CYCLONIC CIRCULATION ACRS NORTHERN PA WL CONT TO ADVECT PLENTY OF MOISTURE ACRS OUR TAF SITES THRU TONIGHT. OVERALL IFR CONDITIONS WL CONT AT SLK/MSS WITH MAINLY IFR AT BTV/MPV/RUT...AND MVFR AT PBG THRU THIS AFTN/EVENING. VAD PROFILE SHOWS NORTHERLY FLW DOWN THE CPV...HELPING TO ENHANCE LLVL MOISTURE CONVERGENCE AT BTV WITH CRNT RADAR SHOWING A BAND OF MODERATE RAIN ROTATING INTO OUR NORTHERN/CENTRAL TAF SITES. OBS INDICATING IFR CONDITIONS WITH VIS BTWN 1-3SM AND CIGS BROKEN TO OVERCAST AT 400 TO 800 FT. THIS BAND OF RAIN WL SLOWLY LIFT FROM SE TO NW ACRS OUR TAF SITES THRU THE REST OF THIS AFTN. THIS EVENING...BOTH RAP AND NAM SHOW A WIND SHIFT TO THE SW BTWN 03Z AND 05Z...WHICH WL RESULT IN DOWNSLOPE FLW AND SOME IMPROVING CIGS AT BTV/PBG. WL MENTION MVFR CONDITIONS. OTHERWISE...ANTICIPATE MAINLY IFR CIGS TO CONT AT MPV/RUT/SLK/MPV WITH PATCHY DRIZZLE/FOG REDUCING VIS BTWN 1-3SM AT TIMES. BUFKIT VERTICAL MOISTURE PROFILES SHOW A SLOW DECREASE IN RH BTWN 13-15Z WITH BETTER MIXING...RESULTING IN MVFR CONDITIONS AT MOST SITES. SLOWEST SITES TO CLR WL BE SLK/MPV. OUTLOOK 18Z MONDAY THROUGH THURSDAY... WEAK SFC RIDGE WL RESULT IN DRYING ALOFT AND AT THE SFC WITH MAINLY VFR CONDITIONS AT BTV/MSS/RUT/PBG AND MVFR BECMG VFR AT MPV/SLK FROM 18Z THRU 18Z WEDS. SOME PATCHY FOG WL BE POSSIBLE AT SLK/MPV MONDAY NIGHT/TUES MORNING. NEXT SYSTEM ARRIVES WEDS AFTN INTO THURS WITH MORE SCATTERED SHOWERS AND POTENTIAL PERIODS OF MVFR CONDITIONS. && .HYDROLOGY... AS OF 300 PM EDT SUNDAY...WIDESPREAD RAINFALL EXPECTED THIS EVENING INTO TONIGHT WITH DEFORMATION/WRAP-AROUND PCPN AFFECTING THE REGION ASSOC WITH PASSG OF UPPER LOW PRESSURE. 24-HR BASIN TOTALS GENERALLY IN THE 0.50 TO 1.0 INCH RANGE ACROSS CENTRAL AND NORTHERN WATERSHEDS...AND 0.25 TO 0.50 INCH SOUTH. ONLY MODESTLY MOIST ANTECEDENT GROUND CONDITIONS AND ONLY SLIGHT TO MODEST RISES ON AREA RIVERS OF 1-2 FEET EXPECTED AS RUNOFF PEAKS BY MONDAY AFTERNOON. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...BANACOS AVIATION...TABER HYDROLOGY...JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
152 PM EDT SUN SEP 30 2012 .SYNOPSIS... AN UPPER LEVEL LOW PRESSURE SYSTEM WILL LIFT THROUGH THE REGION TODAY AND ON MONDAY...BRINGING A CHANCE FOR PRECIPITATION DURING THIS TIME. HIGH PRESSURE RETURNS FOR TUESDAY...FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM FOR WEDNESDAY AND THURSDAY. HIGH PRESSURE WILL MOVE OVER THE AREA AGAIN BY FRIDAY. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... AS OF 1010 AM EDT SUNDAY...SIGNIFICANT CHANGES MADE AS OF MID- MORNING TO RAMP POPS UPWARD ACROSS OUR CENTRAL/NRN COUNTIES PER LATEST RADAR AND 10Z RAP/HRRR COMP REFLECTIVITY PROGS. IMPRESSIVE WRN ATLANTIC MOISTURE PLUME AND ASSOC RAFL CONTINUES TO EVOLVE AND PUSH FAIRLY QUICKLY NORTH/NORTHWESTWARD INTO EAST/SOUTHEAST NEW ENGLAND THIS MORNING IN RESPONSE TO DEEPENING SOUTHERLY FLOW ON THE EAST SIDE OF LARGE-SCALE UPPER CUTOFF LOW OVER THE ERN GREAT LAKES. THIS RAFL SHOULD SPREAD FAIRLY QUICKLY INTO THE NORTHEASTERN HALF OF VERMONT BY 18Z...THEN PIVOT SLOWLY WEST AND THEN SOUTH ACROSS OUR NRN COUNTIES...TAKING ON A PRONOUNCED DEFORMATIONAL SIGNATURE BY THIS EVENING INTO TONIGHT AS UPPER LOW PASSES ATOP AND EAST OF THE REGION. 24-HR PCPN TOTALS BY 12Z MONDAY FROM A FEW TENTHS SOUTH...AND GENERALLY IN THE 0.50 TO 1.0 INCH RANGE NORTH WITH LOCALIZED HIGHER TOTALS ALONG THE WRN NRN MTN SLOPES. IN REGARD TO OTHER WEATHER ELEMENTS...ONLY NOMINAL ADJUSTMENTS WERE MADE TO T/TD/MAX T DATASETS...MAINLY BLENDING CURRENT OBSERVATIONAL DATA IN WITH LATEST LAMP DATA...WHICH WOULD OFFER NEAR STEADY OR SLIGHTLY COOLER VALUES (1-2 DEG) TODAY. REST OF FCST UNCHANGED. PREVIOUS DISCUSSION...CLDY SKIES PERSIST ACROSS THE NORTH COUNTRY THIS MORNING AS A BROAD UPPER LOW CONTINUES TO SPIN OVER THE NORTHEAST. BULK OF PRECIP ASSOCIATED WITH THIS SYSTEM AWAY FROM THE CWA ATTM...WITH ONLY --RW/-DZ AND FG PERSISTING. EXPECTING THESE CONDITIONS TO GO THRU MORNING/EARLY AFTNOON HRS...THEN INCR IN AREAL COVERAGE/INTENSITY COMES TO OUR REGION AS LOW BEGINS TO LIFT NNE INTO QUEBEC. MOISTURE ALONG THE SOUTHERN AND EASTERN PORTIONS OF THE SYSTEM WILL BRING HEAVIER SHOWER ACTIVITY LASTING THRU THE EVENING/OVERNIGHT HRS. DO EXPECT FOCUS OF PRECIP TO SLOWLY SHIFT FROM S TO N AS LOW GOES NORTH OF US. TOWARDS MORNING WITH GENERAL WNW FLOW DEVELOPING...HIGHEST POPS FOR REMAINING SHOWER ACTIVITY WILL BE CONCENTRATED OVER HIR ELEV...ESPECIALLY NE VT. CLDY SKIES THRU THE 24-HR PERIOD WILL KEEP TEMPS FAIRLY STAGNANT. YESTERDAY/S HIGH/LOW COMBO WERE 57F/52F HERE AT BTV. EXPECTING SIMILAR TREND FOR HERE AND REST OF CWA WITH LITTLE TEMP VARIANCE WITH HIGHS IN THE 50S AND LOW IN THE U40S TO AROUND 50F. && .SHORT TERM /11 PM THIS EVENING THROUGH TUESDAY/... AS OF 414 AM EDT SUNDAY...WITH UPPER LOW FINALLY INTO SOUTHERN QUEBEC...REMAINING PRECIP OVER THE AREA WILL FOCUS ON THE NORTHERN ZONES/HIR TRRN. BY MONDAY AFTNOON/EARLY EVENING...WK RIDGE BUILDING NORTH INTO THE AREA WILL FORCE ANY REMAINING PRECIP OVER NE VT OUT OF THE AREA. DRY CONDITIONS OVER THE CWA WILL ONLY LAST MONDAY NGT INTO EARLY TUESDAY AS MDLS BRING NEXT LOW THRU THE OHIO/TENNESSEE VALLEYS AND INTO THE CWA FROM THE SW. BULK OF MEASURABLE PRECIP STAYS MAINLY CONFINED TO N NY WITH --RW FOR CVLY/SW VT. LACK OF THICK CLD COVER WILL ALLOW FOR SLIGHT WARMING TREND THRU THE AREA WITH HIGHS TIPPING UP INTO THE 60-65F RANGE. OVERNGT LOWS GET A BUMP UP AS WELL INTO THE 40S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 324 AM EDT SUNDAY...GOOD RUN-TO-RUN CONSISTENCY NOW SHOWN IN GFS SOLNS LAST SEVERAL CYCLES. GOOD CONSISTENCY WITH 00Z GFS ENSEMBLE AND 00Z ECMWF THROUGH THURSDAY BEFORE ECMWF DIVERGES SIGNIFICANTLY. CURRENT FCST GENERALLY FOLLOWS 00Z GFS. SRN STREAM 500MB TROUGH EXTENDING ACROSS THE MID/LWR MS RIVER VALLEY AT 00Z WEDNESDAY IS EXPECTED TO BE ASSOCIATED WITH A WEAK SFC LOW PRESSURE SYSTEM VCNTY OF THE UPR OHIO VLY/CENTRAL APPALACHIANS. EWD EXTENDING WARM FRONT EXPECTED TO LIFT NWD BRINGING INCREASING CLOUDS AND A CHANCE OF SHOWERS TO THE NORTH COUNTRY TUESDAY NIGHT. 850MB TEMPS PROGGED TO BE QUITE WARM (00Z GFS SHOWS +14C AT 850MB BY 12Z WED). WITH CLOUDS AND WAA SHOULD SEE LOWS GENERALLY IN THE 50S AREAWIDE. WEDNESDAY AND WEDNESDAY NIGHT...EXPECT TO SEE SRN STREAM SHORTWAVE TROUGH BEGIN TO SHEAR NEWD WITH WEAK SFC LOW PASSING WEST OF THE NORTH COUNTRY DURING THE DAY WEDNESDAY. CAN/T RULE OUT CONTINUED CHANCES OF SHOWERS WED/WED NIGHT WITH SKIES REMAINING MOSTLY CLOUDY. AIR MASS QUITE MILD SO HIGHS IN THE LOWER 70S APPEAR MOST LIKELY...WITH LOWS AGAIN IN THE 50S WED NIGHT. SOME CLEARING EXPECTED THURSDAY WITH DRIER CONDITIONS AS TROUGH DEPARTS. 850MB TEMPS COOL SLIGHTLY TO ABOUT +10C FOR THURSDAY SO STILL LOOKING AT HIGHS UPR 60S TO LWR 70S. DEEP-LAYER RIDGE BRIEFLY IN PLACE THU NGT INTO EARLY FRIDAY SO KEPT THAT PERIOD DRY. A COLD FRONT APPROACHES FROM THE GREAT LAKES FRIDAY AFTN WITH CHANCES FOR SHOWERS FRIDAY AFTN ACROSS NRN NY. PRECEDING AIR MASS STILL MILD WITH HIGHS UPR 60S TO LWR 70S LIKELY. SHOWERS AREAWIDE FRIDAY NIGHT ASSOCIATED WITH COLD FRONT. SATURDAY LOOKS COOLER WITH GUSTY WESTERLY WINDS POSSIBLE. MAY STILL SEE SOME ISOLD -SHRA WITH SHALLOW INSTABILITY...ESPECIALLY ACROSS THE HIGHER TERRAIN. HIGHS SATURDAY FORECAST AROUND 60 EXCEPT LOW-MID 50S FOR NRN NY. IT/S WORTH NOTING THAT THE 00Z ECMWF SHOWS A CONSIDERABLY SLOWER ARRIVAL OF THE COLD FRONT...SO IT/S POSSIBLE TEMPERATURES WILL BE WARMER THAN FORECAST SATURDAY WITH FRONTAL PASSAGE NOT UNTIL SATURDAY NIGHT. CURRENT FCST REFLECTS 00Z GFS AND 00Z GFS ENSEMBLE MEAN SOLNS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...DEEP CLOSED 5H/7H CYCLONIC CIRCULATION ACRS NORTHERN PA WL CONT TO ADVECT PLENTY OF MOISTURE ACRS OUR TAF SITES THRU TONIGHT. OVERALL IFR CONDITIONS WL CONT AT SLK/MSS WITH MAINLY IFR AT BTV/MPV/RUT...AND MVFR AT PBG THRU THIS AFTN/EVENING. VAD PROFILE SHOWS NORTHERLY FLW DOWN THE CPV...HELPING TO ENHANCE LLVL MOISTURE CONVERGENCE AT BTV WITH CRNT RADAR SHOWING A BAND OF MODERATE RAIN ROTATING INTO OUR NORTHERN/CENTRAL TAF SITES. OBS INDICATING IFR CONDITIONS WITH VIS BTWN 1-3SM AND CIGS BROKEN TO OVERCAST AT 400 TO 800 FT. THIS BAND OF RAIN WL SLOWLY LIFT FROM SE TO NW ACRS OUR TAF SITES THRU THE REST OF THIS AFTN. THIS EVENING...BOTH RAP AND NAM SHOW A WIND SHIFT TO THE SW BTWN 03Z AND 05Z...WHICH WL RESULT IN DOWNSLOPE FLW AND SOME IMPROVING CIGS AT BTV/PBG. WL MENTION MVFR CONDITIONS. OTHERWISE...ANTICIPATE MAINLY IFR CIGS TO CONT AT MPV/RUT/SLK/MPV WITH PATCHY DRIZZLE/FOG REDUCING VIS BTWN 1-3SM AT TIMES. BUFKIT VERTICAL MOISTURE PROFILES SHOW A SLOW DECREASE IN RH BTWN 13-15Z WITH BETTER MIXING...RESULTING IN MVFR CONDITIONS AT MOST SITES. SLOWEST SITES TO CLR WL BE SLK/MPV. OUTLOOK 18Z MONDAY THROUGH THURSDAY... WEAK SFC RIDGE WL RESULT IN DRYING ALOFT AND AT THE SFC WITH MAINLY VFR CONDITIONS AT BTV/MSS/RUT/PBG AND MVFR BECMG VFR AT MPV/SLK FROM 18Z THRU 18Z WEDS. SOME PATCHY FOG WL BE POSSIBLE AT SLK/MPV MONDAY NIGHT/TUES MORNING. NEXT SYSTEM ARRIVES WEDS AFTN INTO THURS WITH MORE SCATTERED SHOWERS AND POTENTIAL PERIODS OF MVFR CONDITIONS. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JN NEAR TERM...JMG/JN SHORT TERM...JN LONG TERM...BANACOS AVIATION...TABER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
513 PM EDT SUN SEP 30 2012 .SYNOPSIS... A DEEP UPPER LOW PRESSURE SYSTEM WILL ROTATE THROUGH NORTHERN PENNSYLVANIA THIS AFTERNOON...THEN QUICKLY LIFT AWAY FROM THE AREA TONIGHT. HIGH PRESSURE WILL BRIEFLY VISIT THE REGION ON MONDAY. WET WEATHER WILL RETURN TO THE KEYSTONE STATE MONDAY NIGHT THROUGH TUESDAY AS A WAVE OF LOW PRESSURE EJECTS NORTHWARD FROM THE CENTRAL GULF STATES. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... NMRS INSTABILITY SHOWERS NOW EVIDENT ON RADAR ACRS MUCH OF THE CWA...DRIVEN BY THE HEATING OF THE DAY /ALBEIT MODEST/ UNDER H5-H7 COLD POOL OF -15C. THIS IS RESULTING IN MID-LVL LAPSE RATES AROUND 7 C/KM -- A VERY STRONG SIGNAL FOR INSTABILITY SHOWERS. SMALL HAIL WILL BE POSSIBLE IN THE MORE ROBUST...LOW-TOPPED CONVECTIVE CELLS. THE LATEST HRRR HAD DONE QUITE WELL WITH THE SHOWER PLACEMENT THUS FAR...WITH THE GREATEST CONCENTRATION OF SHOWER ACTIVITY ALONG I-80 AND OVR THE LAURELS/S-CENTRAL MTNS. THE BAND OF CONVECTIVE SHOWERS CURRENTLY OVR THE S-CENTRAL MTNS SHOULD REACH THE LWR SUSQ VLY METRO AREAS AROUND 20Z. BKN-OVC CUMULUS/STRATOCU SHOULD START TO FIZZLE OUT THIS EVE WITH PARTIAL CLEARING EXPECTED BY LATE TONIGHT. BY THE SAME TOKEN...EXPECT INSTABILITY SHOWERS/ISOLD TSRA TO QUICKLY FADE AND EVENTUALLY DISSIPATE WITH THE LOSS OF HEATING SHORTLY AFT 00Z. LLVL MSTR MAY GET TRAPPED BLW INVERSION AND RESULT IN LOW STRATUS/FOG INTO EARLY MONDAY MORNING...ESP ACRS THE ALLEGHENIES GIVEN WEAK WNW UPSLOPE. HAVE ADDED MENTION OF FG LATE TONIGHT WITH THE FINAL AFTN UPDATE. OTHERWISE...NO MAJOR CHANGES TO NEAR TERM FCST. OVERNIGHT LOWS WILL BE NEAR SEASONAL NORMALS...WITH THE COLDEST READINGS OVR THE WRN MTNS WHERE THE BEST RADIATIONAL COOLING SHOULD OCCUR. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... AFTER SOME PATCHY EARLY MORNING FOG/LOW CLOUDS...SFC RIDGE WILL BISECT THE STATE...IN BETWEEN DEPARTING NRN STREAM UPPER TROUGH/LOW LIFTING NWD ACRS NRN NEW ENGLAND AND DEVELOPING SRN STREAM WAVE OVR MS/AL. EXPECT AN INCREASE IN MID-HIGH CLOUDS IN ADVANCE OF THE SRN SYSTEM LATE IN THE DAY...AS IT MOVES NWD INTO THE TN VLY BY 00Z TUE. HIGHS WILL BE QUITE PLEASANT IN THE 60S TO LOWER 70S NORTH TO SOUTH. MDLS IN DECENT AGREEMENT IN MOVG THE SFC WAVE INTO TN/KY BY THE END OF THE PERIOD. ANOMALOUS SLY LLJ WILL SUPPORT ROBUST NWD MSTR FLUX INTO THE AREA MON NGT...WITH PWATS SURGING TO +2-3SD BY 12Z TUE. ANOTHER INTERESTING FEATURE IS PERHAPS A DUEL MSTR FEED FM THE GOMEX AND ATM RIVER EMANATING FM THE BAHAMAS. THE LATTER SHOULD BECOME THE MAIN SOURCE OF HI PWATS INTO TUES. THE 12Z MODELS STILL DISPLAY SOME DETAIL DIFFS WITH THIS SYS AND THEREFORE ONLY MADE MINOR TWEAKS TO THE SHORT TERM FCST FOR THE DY2 FINALS. HOWEVER WITH SUPPORT FROM THE 12Z GEFS/09Z SREF...STILL FEEL THAT HIGHER POPS ARE JUSTIFIED /ESPECIALLY FROM 06-12Z TUES/ GIVEN THE STG WAA/ISENT LIFT AND MSTR TRANSPORT INTO THE REGION. && .LONG TERM /TUESDAY THROUGH SUNDAY/... BY TUES...LARGE SCALE PATTERN WILL FEATURE HIGH AMPLITUDE TROUGH WITH UPPER LOW CENTERED NEAR MISSOURI. SFC LOW WILL BE LIFTING INTO THE OHIO VALLEY DRAGGING AN OCCLUDED FRONT THROUGH PA LATER TUE OR TUE NIGHT. THE SHORT RANGE GUIDANCE SHOWS ERODING STABILITY AND SUGGESTS THE POSSIBILITY OF SOME CONVECTION AS THE FRONT GETS CLOSER TUES...MAINLY ACROSS THE SOUTHERN HALF. QPF ON TUE LOOKS TO BE AROUND 0.25 ON AVERAGE...BUT HIGHER AMOUNTS ARE POSS. SOAKING RAIN CONTINUES INTO TUE NIGHT/EARLY WED AS SOUTHERLY FLOW ALOFT RIDES OVER THE SFC LOW...AND SHORTWAVE ENERGY SLIDES AROUND BASE OF TROUGH BEFORE EJECTING INTO OHIO VALLEY WED. MODELS STILL HINTING AT WEAK SECONDARY SFC WAVE DEVELOPMENT TO OUR SE...WHICH MAY PEEL POTENTIAL FOR 1 INCH QPFS AWAY FROM PA RESULTING IN A WIDESPREAD LIGHT TO MODERATE RAIN...AND A MINIMAL FLOOD THREAT AT THIS TIME. AFTER THE SFC LOW/FRONT CLEARS THE AREA...THE UPPER LOW WILL THEN PUSH THROUGH WED/WED NIGHT...KEEPING MENTION OF SHOWERS IN THE FORECAST - MAINLY IN THE WEST AS DRY SLOT APPEARS TO WORK IN WITH RIDGE NOSING IN FROM THE SOUTH. THU AND FRI WILL SEE SFC RIDGING AND W/SW UPPER FLOW...WHICH SHOULD KEEP THE REGION DRY WITH NEAR/SLIGHTLY ABOVE NORMAL TEMPS. MODELS CONTINUE TO PRODUCE DIVERGING FORECASTS FOR THE WEEKEND. THE GEFS/GFS AND CANADIAN MODELS SHOW AN APPROACHING ALBEIT FADING FRONT LATER FRIDAY WITH THE PARENT UPPER SHORTWAVE WANTING TO SHEAR OUT WELL NORTH AND WEST OF HERE. THE ECMWF /UNUSUALLY/ CONTINUES TO BE AN OUTLIER...HOLDING ITS UPPER ENERGY BACK RESULTING IN A BROAD WSW FLOW EVENTUALLY ESTABLISHING OVER THE GR LAKES AND NERN US. THIS RESULTS IN THE MODEL DEVELOPING A SLOW MOVING WAVY ANA-FRONT THAT APPROACHES THE AREA FOR THE WEEKEND. TOUGH TO EVEN LEAN FORECAST ONE WAY OR THE OTHER WITH SUCH DIFFERENCE IN GUIDANCE...SO HAD TO KEEP LOW POPS ACROSS SEVERAL PERIODS...THOUGH PAINTED HIGHEST POPS ON SAT. FOR TEMPS...GRADUALLY OOZED COOLER TEMPERATURES INTO THE REGION FROM SAT INTO MON. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... COLD AIR ALOFT AND DAYTIME HEATING RESULTING IN SCT-BKN CU FIELD ACRS CENTRAL PA TERMINALS LATE THIS AFTN...WITH VFR CLOUD BASES BTWN 5-7KFT AGL. AS EXPECTED...SCT INSTABILITY SHOWERS HAVE DEVELOPED UNDER THE COLD POOL ALOFT...WITH THE MOST CONCENTRATED AREA OF SHRA...AND A FEW TSRA...NEAR THE MASON-DIXON LINE IN ASSOC WITH AN UPPER LVL DISTURBANCE TRACKING ACROSS SOUTHERN PA. ALTHOUGH MOST LOCATIONS WILL REMAIN VFR...CAN/T RULE OUT A LOCALIZED...BRIEF VSBY REDUCTION FROM ONE OF THESE SHOWERS THRU ABOUT 00Z. WITH THE LOSS OF DAYTIME HEATING...EXPECT DIURNAL SHOWERS TO QUICKLY DISSIPATE AFTER SUNSET. SFC HIGH PRES WILL SLIDE INTO THE REGION FROM THE UPPER OH VLY OVERNIGHT. SOME RESIDUAL LLVL MSTR MAY GET TRAPPED UNDER INVERSION AND RESULT IN LOW CIGS/FOG OVERNIGHT...ESP OVR THE WRN MTNS GIVEN WEAK UPSLOPE FLOW. HAVE ADDED A PERIOD OF LOW CIGS/VIS BTWN 09-13Z ACRS THE WRN AND CENTRAL AIRFIELDS. OUTLOOK... MON...AM LOW CIGS/FOG PSBL ACROSS THE W-CENTRAL MTNS...BCMG VFR. TUE...RAIN/LOW CIGS LIKELY. WED...RAIN/LOW CIGS POSSIBLE. THU-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...RXR AVIATION...FITZGERALD/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
226 PM EDT SUN SEP 30 2012 .SYNOPSIS... A DEEP UPPER LOW PRESSURE SYSTEM WILL ROTATE THROUGH NORTHERN PENNSYLVANIA THIS AFTERNOON...THEN QUICKLY LIFT AWAY FROM THE AREA TONIGHT. HIGH PRESSURE WILL BRIEFLY VISIT THE REGION ON MONDAY. WET WEATHER WILL RETURN TO THE KEYSTONE STATE MONDAY NIGHT THROUGH TUESDAY AS A WAVE OF LOW PRESSURE EJECTS NORTHWARD FROM THE CENTRAL GULF STATES. && .NEAR TERM /THROUGH TONIGHT/... NMRS INSTABILITY SHOWERS NOW EVIDENT ON RADAR ACRS MUCH OF THE CWA...DRIVEN BY THE HEATING OF THE DAY /ALBEIT MODEST/ UNDER H5-H7 COLD POOL OF -15C. THIS IS RESULTING IN MID-LVL LAPSE RATES AROUND 7 C/KM -- A VERY STRONG SIGNAL FOR INSTABILITY SHOWERS. SMALL HAIL WILL BE POSSIBLE IN THE MORE ROBUST...LOW-TOPPED CONVECTIVE CELLS. THE LATEST HRRR HAD DONE QUITE WELL WITH THE SHOWER PLACEMENT THUS FAR...WITH THE GREATEST CONCENTRATION OF SHOWER ACTIVITY ALONG I-80 AND OVR THE LAURELS/S-CENTRAL MTNS. THE BAND OF CONVECTIVE SHOWERS CURRENTLY OVR THE S-CENTRAL MTNS SHOULD REACH THE LWR SUSQ VLY METRO AREAS AROUND 20Z. BKN-OVC CUMULUS/STRATOCU SHOULD START TO FIZZLE OUT THIS EVE WITH PARTIAL CLEARING EXPECTED BY LATE TONIGHT. BY THE SAME TOKEN...EXPECT INSTABILITY SHOWERS/ISOLD TSRA TO QUICKLY FADE AND EVENTUALLY DISSIPATE WITH THE LOSS OF HEATING SHORTLY AFT 00Z. LLVL MSTR MAY GET TRAPPED BLW INVERSION AND RESULT IN LOW STRATUS/FOG INTO EARLY MONDAY MORNING...ESP ACRS THE ALLEGHENIES GIVEN WEAK WNW UPSLOPE. HAVE ADDED MENTION OF FG LATE TONIGHT WITH THE FINAL AFTN UPDATE. OTHERWISE...NO MAJOR CHANGES TO NEAR TERM FCST. OVERNIGHT LOWS WILL BE NEAR SEASONAL NORMALS...WITH THE COLDEST READINGS OVR THE WRN MTNS WHERE THE BEST RADIATIONAL COOLING SHOULD OCCUR. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... AFTER SOME PATCHY EARLY MORNING FOG/LOW CLOUDS...SFC RIDGE WILL BISECT THE STATE...IN BETWEEN DEPARTING NRN STREAM UPPER TROUGH/LOW LIFTING NWD ACRS NRN NEW ENGLAND AND DEVELOPING SRN STREAM WAVE OVR MS/AL. EXPECT AN INCREASE IN MID-HIGH CLOUDS IN ADVANCE OF THE SRN SYSTEM LATE IN THE DAY...AS IT MOVES NWD INTO THE TN VLY BY 00Z TUE. HIGHS WILL BE QUITE PLEASANT IN THE 60S TO LOWER 70S NORTH TO SOUTH. MDLS IN DECENT AGREEMENT IN MOVG THE SFC WAVE INTO TN/KY BY THE END OF THE PERIOD. ANOMALOUS SLY LLJ WILL SUPPORT ROBUST NWD MSTR FLUX INTO THE AREA MON NGT...WITH PWATS SURGING TO +2-3SD BY 12Z TUE. ANOTHER INTERESTING FEATURE IS PERHAPS A DUEL MSTR FEED FM THE GOMEX AND ATM RIVER EMANATING FM THE BAHAMAS. THE LATTER SHOULD BECOME THE MAIN SOURCE OF HI PWATS INTO TUES. THE 12Z MODELS STILL DISPLAY SOME DETAIL DIFFS WITH THIS SYS AND THEREFORE ONLY MADE MINOR TWEAKS TO THE SHORT TERM FCST FOR THE DY2 FINALS. HOWEVER WITH SUPPORT FROM THE 12Z GEFS/09Z SREF...STILL FEEL THAT HIGHER POPS ARE JUSTIFIED /ESPECIALLY FROM 06-12Z TUES/ GIVEN THE STG WAA/ISENT LIFT AND MSTR TRANSPORT INTO THE REGION. && .LONG TERM /TUESDAY THROUGH SATURDAY/... THE LARGE SCALE PATTERN QUICKLY RELOADS INTO A HIGH AMPLITUDE TROF OVER THE EASTERN HALF OF THE US. THE DETAILS DIFFER BETWEEN THE VARIOUS MODELS...BUT IT LOOKS LIKE THE CONSENSUS IS FOR A LOW TO MOVE UP TOWARD THE CENTRAL GR LAKES...WITH THE OCCLUDED FRONT EVENTUALLY SWINGING THRU THE REGION SOME TIME TUES NIGHT OR WED. THE SHORT RANGE GUIDANCE SHOWS ERODING STABILITY AND SUGGESTS THE POSSIBILITY OF SOME CONVECTION AS THE FRONT GETS CLOSER TUES. 03Z SREF STILL SHOWS AS MUCH AS A 30-50 PROB OF 24 HOUR RAINFALLS OF AN INCH OR MORE OVER WEST-CENTRAL PA...MAINLY FROM TUESDAY INTO WED. THIS ISN`T MUCH DIFFERENT THAN THE 21Z RUN. THE GEFS IS NOT NEARLY AS AGGRESSIVE AND HAS SHIFTED ITS LOWER PROBABILITY OF ONE INCH RAINS MAINLY OFF TO OUR SE...WHICH MATCHES BETTER TO WHERE THE OPERATIONAL MODEL SUGGESTS THE POSSIBILITY OF A COASTAL SECONDARY WAVE TO FORM. AT THIS STAGE THE DIFFERENCES IN GUIDANCE MUDDY THE DETAILS...BUT WHAT LOOKS ALMOST ASSURED IS THAT WE WILL SEE A WIDESPREAD LIGHT TO MODERATE RAIN...AND A MINIMAL FLOOD THREAT AT THIS TIME. AFTER THE SFC LOW/FRONT MOVES THROUGH...THE UPPER LOW WILL THEN PUSH THROUGH WED/WED NIGHT KEEPING THE MENTION OF SHOWERS IN THE FORECAST. BY THURSDAY WE SHOULD SEE ENOUGH RIDGING FROM THE WEST TO DRY OUT...AT LEAST TEMPORARILY. THE GEFS/GFS AND CANADIAN MODELS SHOW AN APPROACHING ALBEIT FADING FRONT BY FRIDAY WITH THE PARENT UPPER SHORTWAVE WANTING TO SHEAR OUT WELL NORTH AND WEST OF HERE. THE ECMWF AT THIS POINT IS AN OUTLIER...HANGING MORE UPPER ENERGY BACK ITO THE NORTHERN ROCKIES...RESULTING IN A BROAD WSW FLOW EVENTUALLY ESTABLISHING OVER THE GR LAKES AND NERN US. THIS RESULTS IN THE MODEL DEVELOPING A SLOW MOVING WAVY ANA-FRONT THAT APPROACHES THE AREA FOR THE WEEKEND. DEPENDING ON TIMING...IT COULD EITHER BE MILD AND DRY...OR CHILLY AND RAINY. AS A RESULT...HAVE CHOSEN TO NOT TOUCH THE EXTENDED PORTION OF THE FORECAST WHERE WE NOW HAVE SMALL CHANCES FOR RAIN...WHICH WOULD BETTER FIT A WASHING FRONTAL PASSAGE CONCEPTUAL MODEL. IT DOES LOOK LIKE ONCE THE RAIN MOVES THROUGH...WE SHOULD ENJOY SEVERAL DAYS OF ABOVE NORMAL WARMTH STARTING ABOUT WEDNESDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... 30/18Z...COLD AIR ALOFT AND DAYTIME HEATING RESULTING IN BKN CU/SC FIELD ACRS CENTRAL PA TERMINALS THIS AFTN...WITH LOW-END VFR CLOUD BASES BTWN 3.5-6KFT AGL. AS EXPECTED...SCT TO NMRS INSTABILITY SHOWERS HAVE DEVELOPED UNDER THE COLD POOL ALOFT ASSOC WITH A CLOSED UPPER LEVEL LOW PIVOTING OVR PA/NY. OCNL CG LTG IS ALSO BEING OBSERVED IN SOME OF THE MORE ROBUST CELLS...AND CANT RULE OUT A LCL TSRA IMPACT THRU EARLY EVE. HOWEVER CVRG/CONFIDENCE REMAIN TOO LOW FOR MENTION IN TAFS. WITH THE LOSS OF DAYTIME HEATING...EXPECT DIURNAL SHOWERS TO QUICKLY DISSIPATE SHORTLY AFT 00Z. SFC HIGH PRES WILL SLIDE INTO THE REGION FROM THE UPPER OH VLY OVERNIGHT. SOME RESIDUAL LLVL MSTR MAY GET TRAPPED UNDER INVERSION AND RESULT IN LOW CIGS/FOG OVERNIGHT...ESP OVR THE WRN MTNS GIVEN WEAK UPSLOPE FLOW. HAVE ADDED A PERIOD OF LOW CIGS/VIS BTWN 09-13Z ACRS THE WRN AND CENTRAL AIRFIELDS. OUTLOOK... MON...AM LOW CIGS/FOG PSBL ACROSS THE W-CENTRAL MTNS...BCMG VFR. TUE...RAIN/LOW CIGS LIKELY. WED...RAIN/LOW CIGS POSSIBLE. THU-FRI...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LA CORTE AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1259 PM CDT SUN SEP 30 2012 .AVIATION...DISCUSSION FOR 18Z TAFS VFR CONDITIONS SHOULD DOMINATE. SCT SHOWERS AND STORMS WILL AFFECT THE AREA THIS AFTERNOON AND HAVE INCLUDED VCTS AT KGUY AND KDHT FROM 30/21Z - 01/01Z. WITH SLIGHTLY LESS CONFIDENCE...ONLY UTILIZED VCSH AT KAMA. MVFR CIGS/VSBYS CANNOT BE RULED OUT IN ANY HEAVIER THUNDERSTORMS THIS AFTERNOON...BUT CONFIDENCE IS TOO LOW TO INCLUDE AT THIS TIME AND WILL AMEND AS NECESSARY. UNLESS A TAF SITE SEES SIGNIFICANT RAIN THIS AFTERNOON...FOG IS UNLIKELY TO DEVELOP MONDAY MORNING. WINDS WILL BE LIGHT AND VARIABLE INITIALLY...EVENTUALLY TAKING ON A NORTHERLY DIRECTION AT ABOUT 10-12KTS. GUSTS TO 20 KTS WILL BECOME LIKELY BY LATE MORNING MONDAY...BUT ELECTED NOT TO INCLUDE ANOTHER LINE AT THE VERY END OF THE TAF FOR THIS. SIMPSON && .PREV DISCUSSION... /ISSUED 1150 AM CDT SUN SEP 30 2012/ UPDATE... QUICK UPDATE TO REMOVE DENSE FOG WORDING FROM ZONES AND INCREASE POPS THIS AFTERNOON AS A SHRTWV IN NRLY FLOW SHOULD INTERACT WITH A SFC TROUGH TO PROMOTE SCT STORMS AFTER 19-20Z. LATEST RUC FCST SHOWS 1500-2000 J/KG OF UNCAPPED MLCAPE BY MID AFTERNOON...WITH OTHER MODELS SHOWING SLIGHTLY LESS INSTABILITY. RELATIVELY WEAK BULK SHEAR OF 25-30KTS COULD PROMOTE MINIMAL STORM ORGANIZATION...BUT LACKING LOW LVL DRY AIR SHOULD LIMIT DOWNDRAFT POTENTIAL. HAIL UP TO QUARTER SIZE AND AN ISOLATED 60 MPH DOWNDRAFT COULD BE POSSIBLE IN STRONGER STORMS...BUT EXPECT MOST CONVECTION THAT DOES DEVELOP THIS AFTERNOON TO REMAIN JUST UNDER SVR LIMITS. SIMPSON PREV DISCUSSION... /ISSUED 642 AM CDT SUN SEP 30 2012/ AVIATION... FOR THE 12Z KAMA TAF...THINK THE THREAT OF FG REDUCING VISIBILITIES TO AIRFIELD MINIMUMS IS MOSTLY OVER...THOUGH COULD SEE TEMPO MVFR CONDITIONS OVER THE NEXT FEW HOURS. THE LIGHT SW WINDS HAVE HELPED SCOUR OUT THE FG AND BRING IN SLIGHTLY DRIER AIR. THERE IS A SLIGHT CHANCE...20 PERCENT...OF TSRA BETWEEN 18 AND 06Z...BUT THIS LOOKS VERY UNLIKELY GIVEN LACK OF A SOURCE OF LOW LEVEL LIFT...AND UNFAVORABLE MEAN FLOW TO BRING TSRA FROM ROCKIES THIS FAR E. GFS LAMP SHOWS BR AND LOW CEILINGS REDEVELOPING TONIGHT...BUT THINK THIS IS UNLIKELY GIVEN LACK OF SIGNIFICANT RAIN FALL OVER THE LAST 24 HOURS PLUS SLIGHT DOWNSLOPE COMPONENT IN THE WINDS FOR MUCH OF THE TAF PERIOD. IN ADDITION...THE TIME HEIGHT DISPLAYS FOR BOTH THE GFS AND NAM SHOW LOW LEVEL RELATIVE HUMIDITY VALUES WELL BELOW SATURATION. FOR THE 12Z KDHT AND KGUY TAFS...LOW CEILINGS AND FG SHOULD INTERMITTENTLY AFFECT THE TAF SITES...ESPECIALLY KDHT...FOR THE NEXT 3 HOURS BEFORE DISSIPATING WITH INCREASED MIXING IN A TYPICAL DIURNAL PATTERN. THERE IS A SMALL CHANCE...20 TO 30 PERCENT...OF TSRA BETWEEN 18 AND 06Z. FOR NOW HAVE LEFT MENTION OUT OF THE TAFS AS THE MEAN FLOW THROUGH THIS PERIOD SHOULD BE NORTHERLY...WHICH IS SOMEWHAT UNFAVORABLE FOR TSRA THAT DEVELOPS ON THE HIGHER TERRAIN IN NM AND CO PROPAGATING THIS FAR E. GFS LAMP SHOWS BR AND LOW CEILINGS REDEVELOPING AFTER 06Z...BUT THINK THIS IS UNLIKELY GIVEN LACK OF SIGNIFICANT RAIN FALL OVER THE PAST DAY. IN ADDITION...THE TIME HEIGHT DISPLAYS FOR BOTH THE GFS AND NAM SHOW LOW LEVEL RELATIVE HUMIDITY VALUES WELL BELOW SATURATION DURING THIS TIME. JOHNSON PREV DISCUSSION... /ISSUED 306 AM CDT SUN SEP 30 2012/ DISCUSSION... NORTHWESTERLY TO NORTH NORTHWESTERLY FLOW ALOFT TODAY WILL ALLOW FOR SHORTWAVE ENERGY OVER THE CENTRAL ROCKIES TO APPROACH THE PANHANDLES BETWEEN 18Z TODAY AND 00Z MONDAY. CONVECTION SHOULD DEVELOP THIS AFTERNOON AND INTO THIS EVENING ACROSS THE MOUNTAINS AND HIGHER TERRAIN OF SOUTHERN COLORADO AND NORTHERN NEW MEXICO AND TRACK SOUTHEASTWARD INTO THE PANHANDLES. REMOVED MENTION OF PRECIP AND POPS THIS MORNING AS RADIATIONAL COOLING FOG DEVELOPING ACROSS THE FORECAST AREA...DENSE IN MANY LOCATIONS...AND SHOULD PREVAIL UNTIL AROUND 15Z TO 16Z TODAY BEFORE LIFTING. THE DENSE FOG ADVISORY LOOKS TO BE ON TRACK AND WILL CONTINUE ADVISORY UNTIL EXPIRATION. COLD FRONT PUSHES THROUGH THE PANHANDLES LATE TONIGHT...AFTER 09Z TO 15Z MONDAY...WITH A WIND SHIFT TO THE NORTH AND INCREASE IN SPEED. WIND ADVISORY CRITERIA NOT EXPECTED AT THIS TIME...HOWEVER BREEZY TO WINDY CONDITIONS EXPECTED MONDAY. MODELS IN GOOD AGREEMENT IN BRINGING DOWN ANOTHER SHORTWAVE OUT OF WESTERN KANSAS AND EASTERN COLORADO MONDAY MORNING ON NORTHERLY FLOW ALOFT. FAVORABLE JET DYNAMICS AND COLD FRONT PUSHING THROUGH WILL ALLOW SHOWERS TO TRACK SOUTHWARD INTO MAINLY THE EASTERN HALF OR TWO-THIRDS OF THE PANHANDLES MONDAY AND THEN DRIER CONDITION MONDAY NIGHT THROUGH THE MIDDLE OF THE WEEK. ANOTHER MUCH STRONGER COLD FRONT APPROACHES THE FORECAST AREA WEDNESDAY NIGHT AND SHOULD MOVE THROUGH ALL OF THE PANHANDLES BY MID MORNING THURSDAY. LOWERED TEMPERATURES FURTHER THURSDAY AND FRIDAY. UPSLOPE SURFACE FLOW AND FAVORABLE ISENTROPIC LIFT BY FRIDAY NIGHT INTO SATURDAY WILL RESULT IN INCREASED CHANCES FOR MAINLY SHOWERS ACROSS MUCH OF THE PANHANDLES. WILL INTRODUCE POPS FRIDAY NIGHT AND SATURDAY FOR SHOWERS AND POSSIBLE THUNDERSTORMS...MAINLY DURING THE DAYTIME PERIOD. SCHNEIDER FIRE WEATHER... ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED THROUGH NEXT SATURDAY. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 09/08
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1150 AM CDT SUN SEP 30 2012 .UPDATE... QUICK UPDATE TO REMOVE DENSE FOG WORDING FROM ZONES AND INCREASE POPS THIS AFTERNOON AS A SHRTWV IN NRLY FLOW SHOULD INTERACT WITH A SFC TROUGH TO PROMOTE SCT STORMS AFTER 19-20Z. LATEST RUC FCST SHOWS 1500-2000 J/KG OF UNCAPPED MLCAPE BY MID AFTERNOON...WITH OTHER MODELS SHOWING SLIGHTLY LESS INSTABILITY. RELATIVELY WEAK BULK SHEAR OF 25-30KTS COULD PROMOTE MINIMAL STORM ORGANIZATION...BUT LACKING LOW LVL DRY AIR SHOULD LIMIT DOWNDRAFT POTENTIAL. HAIL UP TO QUARTER SIZE AND AN ISOLATED 60 MPH DOWNDRAFT COULD BE POSSIBLE IN STRONGER STORMS...BUT EXPECT MOST CONVECTION THAT DOES DEVELOP THIS AFTERNOON TO REMAIN JUST UNDER SVR LIMITS. SIMPSON && .PREV DISCUSSION... /ISSUED 642 AM CDT SUN SEP 30 2012/ AVIATION... FOR THE 12Z KAMA TAF...THINK THE THREAT OF FG REDUCING VISIBILITIES TO AIRFIELD MINIMUMS IS MOSTLY OVER...THOUGH COULD SEE TEMPO MVFR CONDITIONS OVER THE NEXT FEW HOURS. THE LIGHT SW WINDS HAVE HELPED SCOUR OUT THE FG AND BRING IN SLIGHTLY DRIER AIR. THERE IS A SLIGHT CHANCE...20 PERCENT...OF TSRA BETWEEN 18 AND 06Z...BUT THIS LOOKS VERY UNLIKELY GIVEN LACK OF A SOURCE OF LOW LEVEL LIFT...AND UNFAVORABLE MEAN FLOW TO BRING TSRA FROM ROCKIES THIS FAR E. GFS LAMP SHOWS BR AND LOW CEILINGS REDEVELOPING TONIGHT...BUT THINK THIS IS UNLIKELY GIVEN LACK OF SIGNIFICANT RAIN FALL OVER THE LAST 24 HOURS PLUS SLIGHT DOWNSLOPE COMPONENT IN THE WINDS FOR MUCH OF THE TAF PERIOD. IN ADDITION...THE TIME HEIGHT DISPLAYS FOR BOTH THE GFS AND NAM SHOW LOW LEVEL RELATIVE HUMIDITY VALUES WELL BELOW SATURATION. FOR THE 12Z KDHT AND KGUY TAFS...LOW CEILINGS AND FG SHOULD INTERMITTENTLY AFFECT THE TAF SITES...ESPECIALLY KDHT...FOR THE NEXT 3 HOURS BEFORE DISSIPATING WITH INCREASED MIXING IN A TYPICAL DIURNAL PATTERN. THERE IS A SMALL CHANCE...20 TO 30 PERCENT...OF TSRA BETWEEN 18 AND 06Z. FOR NOW HAVE LEFT MENTION OUT OF THE TAFS AS THE MEAN FLOW THROUGH THIS PERIOD SHOULD BE NORTHERLY...WHICH IS SOMEWHAT UNFAVORABLE FOR TSRA THAT DEVELOPS ON THE HIGHER TERRAIN IN NM AND CO PROPAGATING THIS FAR E. GFS LAMP SHOWS BR AND LOW CEILINGS REDEVELOPING AFTER 06Z...BUT THINK THIS IS UNLIKELY GIVEN LACK OF SIGNIFICANT RAIN FALL OVER THE PAST DAY. IN ADDITION...THE TIME HEIGHT DISPLAYS FOR BOTH THE GFS AND NAM SHOW LOW LEVEL RELATIVE HUMIDITY VALUES WELL BELOW SATURATION DURING THIS TIME. JOHNSON PREV DISCUSSION... /ISSUED 306 AM CDT SUN SEP 30 2012/ DISCUSSION... NORTHWESTERLY TO NORTH NORTHWESTERLY FLOW ALOFT TODAY WILL ALLOW FOR SHORTWAVE ENERGY OVER THE CENTRAL ROCKIES TO APPROACH THE PANHANDLES BETWEEN 18Z TODAY AND 00Z MONDAY. CONVECTION SHOULD DEVELOP THIS AFTERNOON AND INTO THIS EVENING ACROSS THE MOUNTAINS AND HIGHER TERRAIN OF SOUTHERN COLORADO AND NORTHERN NEW MEXICO AND TRACK SOUTHEASTWARD INTO THE PANHANDLES. REMOVED MENTION OF PRECIP AND POPS THIS MORNING AS RADIATIONAL COOLING FOG DEVELOPING ACROSS THE FORECAST AREA...DENSE IN MANY LOCATIONS...AND SHOULD PREVAIL UNTIL AROUND 15Z TO 16Z TODAY BEFORE LIFTING. THE DENSE FOG ADVISORY LOOKS TO BE ON TRACK AND WILL CONTINUE ADVISORY UNTIL EXPIRATION. COLD FRONT PUSHES THROUGH THE PANHANDLES LATE TONIGHT...AFTER 09Z TO 15Z MONDAY...WITH A WIND SHIFT TO THE NORTH AND INCREASE IN SPEED. WIND ADVISORY CRITERIA NOT EXPECTED AT THIS TIME...HOWEVER BREEZY TO WINDY CONDITIONS EXPECTED MONDAY. MODELS IN GOOD AGREEMENT IN BRINGING DOWN ANOTHER SHORTWAVE OUT OF WESTERN KANSAS AND EASTERN COLORADO MONDAY MORNING ON NORTHERLY FLOW ALOFT. FAVORABLE JET DYNAMICS AND COLD FRONT PUSHING THROUGH WILL ALLOW SHOWERS TO TRACK SOUTHWARD INTO MAINLY THE EASTERN HALF OR TWO-THIRDS OF THE PANHANDLES MONDAY AND THEN DRIER CONDITION MONDAY NIGHT THROUGH THE MIDDLE OF THE WEEK. ANOTHER MUCH STRONGER COLD FRONT APPROACHES THE FORECAST AREA WEDNESDAY NIGHT AND SHOULD MOVE THROUGH ALL OF THE PANHANDLES BY MID MORNING THURSDAY. LOWERED TEMPERATURES FURTHER THURSDAY AND FRIDAY. UPSLOPE SURFACE FLOW AND FAVORABLE ISENTROPIC LIFT BY FRIDAY NIGHT INTO SATURDAY WILL RESULT IN INCREASED CHANCES FOR MAINLY SHOWERS ACROSS MUCH OF THE PANHANDLES. WILL INTRODUCE POPS FRIDAY NIGHT AND SATURDAY FOR SHOWERS AND POSSIBLE THUNDERSTORMS...MAINLY DURING THE DAYTIME PERIOD. SCHNEIDER FIRE WEATHER... ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED THROUGH NEXT SATURDAY. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 09/08
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
259 PM CDT SUN SEP 30 2012 .SHORT TERM...TONIGHT THROUGH WEDNESDAY 259 PM CDT SUN SEP 30 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION POTENTIAL MONDAY AFTERNOON/EVENING AND TEMPERATURES THROUGHOUT. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING NEAR THE U.S. WEST COAST...A SHORTWAVE TROUGH DROPPING DOWN INTO SOUTH CENTRAL CANADA AND NORTH DAKOTA...UPPER LOWS OVER THE SOUTHERN PLAINS AND NEW ENGLAND...AND RIDGING OVER THE FORECAST AREA. OTHER THAN SOME CIRRUS STREAMING NORTHEAST ACROSS IOWA AHEAD OF THE SOUTHERN PLAINS UPPER LOW...MOSTLY SUNNY SKIES EXIST ACROSS MUCH OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY REGION. THIS IS DUE TO PLENTIFUL DRY AIR SEEN ON 12Z SOUNDINGS FROM ABR...MPX AND GRB...WHERE DEWPOINT DEPRESSIONS OF 10C OR MORE EXISTED THROUGHOUT MUCH OF THE TROPOSPHERE. AT THE SURFACE...HIGH PRESSURE WAS SITUATED ACROSS THE GREAT LAKES WHILE A COLD FRONT EXTENDED FROM THE MANITOBA/ONTARIO BORDER SOUTHWEST INTO CENTRAL SOUTH DAKOTA. SHARP 850MB TEMPERATURE GRADIENT EXISTS BETWEEN THESE TWO SURFACE FEATURES...NOTED BY 12Z SOUNDING DATA OF 15C AT INL AND MPX COMPARED TO 8C AT GRB. THIS HAS RESULTED IN A SIMILAR SHARP GRADIENT IN CURRENT TEMPERATURES....FROM THE LOWER 80S IN WESTERN MINNESOTA TO THE UPPER 60S IN EASTERN WISCONSIN. TONIGHT AND MONDAY...SHORTWAVE TROUGH COMING INTO NORTH DAKOTA IS PROGGED TO SPLIT APART INTO TWO BY THE 30.12Z GFS/UKMET/CANADIAN AND ECMWF...WITH PART OF IT HEADING INTO NORTHWEST ONTARIO AND THE OTHER DROPPING SOUTH INTO NEBRASKA BY LATE MONDAY. THIS SCENARIO CREATES SOME ISSUES FOR PRECIPITATION TO OCCUR...SINCE THE UPPER LEVEL FORCING GETS SPLIT AROUND THE FORECAST AREA. PLUS THE AIRMASS IS QUITE DRY. ALL FOUR MODELS SUGGEST A DRY FORECAST. THE 30.00Z ECMWF AND 30.12Z NAM ON THE OTHER HAND KEEP MOST OF THE TROUGH TOGETHER....DROPPING IT INTO MN AND IA DURING THE AFTERNOON. AS SUCH...STRONGER FORCING EXISTS AND A FRONTOGENETICAL BAND OF LIGHT RAIN IS FORECAST TO MOVE INTO NORTHWEST SECTIONS OF THE FORECAST AREA DURING THE AFTERNOON. HAVE FOLLOWED THE MAJORITY OF THE 30.12Z GUIDANCE AND PULLED OUT PRECIPITATION CHANCES ENTIRELY. BOTH SCENARIOS STILL HAVE THE COLD FRONT OVER THE EASTERN DAKOTAS SLIDE INTO THE FORECAST AREA WITH SIMILAR TIMING...SLOWLY MOVING THROUGH DURING THE COURSE OF THE DAY MONDAY. AS SUCH...THERE COULD BE SOME SLIGHT COOLING IN SOUTHEAST MINNESOTA LATE IN THE DAY. OTHERWISE... 850MB TEMPS OF 10-12C AT 18Z MONDAY COMBINED WITH MID/HIGH CLOUD COVER SHOULD SUPPORT HIGHS TOPPING OUT IN THE UPPER 60S TO LOW 70S. ENOUGH HIGH CLOUDS AND A SOUTHERLY GRADIENT LOOKS TO BE IN PLACE TONIGHT TO PRECLUDE ANY VALLEY FOG DEVELOPMENT. THEY SHOULD ALSO RESULT IN WARMER LOWS...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. GOING PREVIOUS FORECAST LOWS LOOK REASONABLE...WITH THE TYPICAL WISCONSIN COLD SPOTS DROPPING INTO THE UPPER 30S DUE TO A LONGER PERIOD OF DECOUPLED WINDS. MONDAY NIGHT AND TUESDAY...THE POSSIBLY SPLIT SHORTWAVE TROUGH LOOKS TO MOVE THROUGH THE FORECAST AREA LATE MONDAY NIGHT...WITH RIDGING BUILDING IN FROM THE WEST ON TUESDAY AS A POTENT UPPER TROUGH BEGINS TO DROP SOUTH INTO MONTANA. AGAIN WHETHER OR NOT PRECIPITATION FALLS MONDAY NIGHT DEPENDS ON HOW SPLIT APART THAT SHORTWAVE TROUGH IS... WITH THE 30.00Z ECMWF DEPICTING A MUCH BETTER CHANCE OF RAIN COMPARED TO THE 30.12Z NAM/GFS/UKMET/CANADIAN/ECMWF. CONTINUED TO FOLLOW THE DRY MAJORITY AS WELL AS PREVIOUS DRY FORECAST. STILL...AFTER 06Z TUESDAY...DRY WEATHER SHOULD BE THE RULE WITH SKIES CLEARING OUT...ESPECIALLY OVER THE NORTHWESTERN 2/3 OF THE AREA. TEMPERATURES SHOULD STILL REMAIN SEASONABLE MONDAY NIGHT...DESPITE THE COLD FRONTAL PASSAGE...DUE TO A COMBINATION OF THE CLOUDS AND 850MB TEMPS ONLY FALLING TO 6-8C BY 12Z TUESDAY. GENERALLY FOLLOWED A BLEND OF GUIDANCE WHICH RESULTS IN LOWS IN THE 40S. WITH SUN BACK OUT FOR TUESDAY AND THE GIVEN 850MB TEMPS...HIGHS REACHING UP INTO THE UPPER 60S TO LOW 70S SEEM REASONABLE. TUESDAY NIGHT AND WEDNESDAY...THE POTENT UPPER TROUGHING DROPPING INTO MONTANA ON TUESDAY IS PROGGED TO CONTINUE DIGGING SOUTHEAST... INTO WYOMING AND PERHAPS THE DAKOTAS AS WELL BY 00Z THURSDAY. AS THIS TROUGH DIGS...IT HELPS TO KICK OUT THE STALLED UPPER LOW IN THE SOUTHERN PLAINS. MODEL TRENDS HAVE SHOWN A LOT OF RETROGRESSION THE PAST COUPLE OF DAYS WITH THIS UPPER LOW...WHICH IS NOW SLATED TO LIFT UP THROUGH LOWER MICHIGAN ON WEDNESDAY. A DEFORMATION PRECIPITATION BAND ASSOCIATED WITH THIS UPPER LOW IS FORECAST BY THE 30.12Z NAM TO PERHAPS CLIP PORTIONS OF GRANT AND ADAMS COUNTIES ON WEDNESDAY. THE NAM IS A WESTERN OUTLIER...WITH ALL OTHER MODELS KEEPING THE BAND TRACKING NOT MUCH FARTHER WEST THAN THE CHICAGO AREA. THEREFORE...HAVE DISCOUNTED THE NAM AT THIS TIME...AND WILL FOLLOW THE MAJORITY SHOWING UPPER RIDGING HOLDING OVER THE FORECAST AREA BETWEEN THE POTENT UPPER TROUGH AND UPPER LOW. SUBSIDENCE AND DRY AIR UNDER THIS UPPER RIDGE IS EXPECTED TO RESULT IN DRY WEATHER FOR THIS TUESDAY NIGHT AND WEDNESDAY PERIOD. DEPENDING ON CLOUD COVER AND IF IT RAINS MONDAY NIGHT...COULD BE A CONCERN FOR VALLEY FOG TUESDAY NIGHT...SINCE A SURFACE RIDGE OF HIGH PRESSURE SHOULD BE IN PLACE. OTHERWISE...TEMPERATURES LOOK FAIRLY MILD FOR EARLY OCTOBER WITH LOWS STILL IN THE 40S AND 850MB TEMPS OF 10-12C ON WEDNESDAY BOOSTING HIGHS INTO THE LOW TO MID 70S. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 259 PM CDT SUN SEP 30 2012 IN THE MEAN...THE 30.12Z ECMWF/CANADIAN/GFS AND GFS ENSEMBLES ALL CONTINUE TO FORECAST A BIG CHANGE IN THE UPPER LEVEL PATTERN DURING THE LONG TERM PERIOD. BY THE WEEKEND...THERE SHOULD BE DEEP UPPER LEVEL TROUGHING IN PLACE ACROSS THE EASTERN TWO THIRDS OF CANADA AS WELL AS THE NORTHERN PLAINS EASTWARD INTO THE GREAT LAKES. FALL WILL REALLY BE FELT THIS WEEKEND AS 850MB TEMPS PLUMMET TO BELOW -2C. PLENTY OF DIFFERENCES EXIST ON HOW WE GET TO THE WEEKEND...MOSTLY RELATED TO THAT POTENT TROUGH THE DIGS INTO WYOMING ON WEDNESDAY. THE 30.12Z ECMWF/CANADIAN/GFS ALL HAVE THE POTENT TROUGH TURNING NEGATIVE TILT AS IT COMES ACROSS THE NORTHERN PLAINS INTO MINNESOTA WEDNESDAY NIGHT AND THURSDAY. HOW FAR NORTHWEST THIS TURN TO NEGATIVE TILT OCCURS AND TIMING IS AT ODDS AMONGST THE MODELS...WITH THE 30.00Z ECMWF/30.12Z CANADIAN FARTHER TO THE NORTHWEST THAN THE 30.12Z GFS. THIS HAS MAJOR IMPLICATIONS ON HOW MUCH PRECIPITATION AND COLD AIR TIMING. IN THE CASE OF THE 30.00Z ECMWF/30.12Z CANADIAN...THEY ARE MUCH LIGHTER ON PRECIPITATION COMPARED TO THE 30.12Z GFS. NEW 30.12Z ECMWF IS COMPLETELY DRY. FOR NOW...WILL FOLLOW A CONSENSUS APPROACH WITH 20 CHANCES WEDNESDAY NIGHT AND 30-50 ON THURSDAY. ALSO OF NOTE IS THE 30.12Z ECMWF/CANADIAN ARE MUCH FASTER THAN THE GFS. MUCH COOLER DAY ANTICIPATED ON THURSDAY TOO AS THE COLD FRONT PASSES...SENDING 850MB TEMPS DOWN TO 0-4C BY 00Z FRIDAY. BREEZY NORTHWEST WINDS LIKELY TOO BEHIND THE FRONT... ESPECIALLY IF THE GFS PANS OUT. MAINLY DRY WEATHER SHOULD FOLLOW FOR THURSDAY NIGHT. FOR FRIDAY AND SATURDAY...THE 30.00Z/30.12Z ECMWF SHOW SOME FRONTOGENESIS-TYPE LIGHT RAIN OCCURRING ACROSS MUCH OF THE FORECAST AREA...NORTH OF A STALLED BOUNDARY FROM KANSAS TO INDIANA. THE 30.12Z GFS/CANADIAN HAVE THIS BOUNDARY MUCH FARTHER SOUTH...RESULTING IN DRY CONDITIONS. GIVEN THE GENERALLY GOOD PERFORMANCE OF THE ECMWF...NEED TO HAVE AT LEAST SOME 20 PERCENT CHANCES FOR FRIDAY AND SATURDAY...ESPECIALLY SOUTH OF I-90. ALL MODELS HAVE HIGH PRESSURE CROSSING THE AREA ON SUNDAY...THUS DRIER WEATHER IS EXPECTED. && .AVIATION...THIS AFTERNOON THROUGH MONDAY 1215 PM CDT SUN SEP 30 2012 HIGH PRESSURE AND LIGHT EAST TO SOUTHEAST WIND FLOW WILL KEEP A DRY AIRMASS AND GOOD VFR CONDITIONS OVER THE AREA THIS AFTERNOON AND TONIGHT. AN APPROACHING MID LEVEL TROUGH WILL SPREAD INCREASING MID AND HIGH LEVEL MOISTURE ACROSS THE AREA TONIGHT AND TUESDAY. SCT-BKN CIRRUS THIS AFTERNOON AND EVENING WILL GIVE WAY TO SCT-BKN 8K TO 12K MID CLOUDS LATE TONIGHT/MON AS THE MID LEVEL TROUGH/SHORTWAVE APPROACHES AND MOVES ACROSS THE AREA. THERE MAY BE WDLY SCT -SHRA AROUND THE AREA LATER MON MORNING INTO MON AFTERNOON BUT GIVEN UNCERTAINTY AND THE DRIER SFC-8K FT AIRMASS BELOW THE MOISTURE AND MID LEVEL LIFT...LEFT VCSH OUT OF THE LATE PORTIONS OF THE TAFS FOR NOW. PASSAGE OF THE SFC FRONT WILL SWITCH THE WINDS FROM SOUTH AHEAD OF IT TO NORTHWEST BEHIND IT...AROUND 14Z MON AT KRST AND AROUND 18Z MON AT KLSE. && .ARX WATCHES/WARNINGS/ADVISORIES... 259 PM CDT SUN SEP 30 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RRS