Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/06/14


AREA FORECAST DISCUSSION
NWS NEW YORK NY
1013 PM EST FRI DEC 5 2014 .SYNOPSIS... LOW PRESSURE OVER THE SOUTHERN PLAINS WILL TREK TOWARDS THE REGION THRU SAT. STRONG HIGH PRESSURE WILL PASS TO THE NORTH FROM SUNDAY INTO MONDAY. A COASTAL STORM WILL THEN LIKELY IMPACT THE REGION FROM MONDAY NIGHT INTO WEDNESDAY...FOLLOWED BY FAIR WEATHER FOR THURSDAY AND FRIDAY AS THE STORM PULLS SLOWLY AWAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... BASED ON LATEST HURR, RAP AND RADAR TRENDS...RAIN BECOMES LIGHTER STARTING JUST BEFORE MIDNIGHT FROM WEST TO EAST. WILL USE LIGHT RAIN. RAIN SHOULD STOP OR BECOME INTERMITTENT OVERNIGHT AS THE WARM FRONT LIFT TO THE NORTH. IN WESTERN ORANGE COUNTY...TEMPS ARE AT FREEZING OR JUST ABOVE. BASED ON REPORTS OF ICING ON ROADS AND DOT REPORTS OF ROADWAY TEMPS BEING BELOW AIR TEMPS WILL MAKE THE WSW EXPIRE AT 1 AM IN CONCERT WITH THE ADVISORY FOR NW NJ. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... FORECAST IS ON TRACK WITH THE LATEST NWP. FRONTOGENESIS ALONG THE WARM FRONT ON THE NORTH SIDE OF THE FORECAST AREA FROM THE MID HUDSON VALLEY TO NORTHERN CT AS SFC LOW PRESSURE TRACKS EAST ACROSS VA. THUS EXPECT DRY WX FOR A GOOD PORTION OF THE MORNING AND EARLY AFTN. THERE AFTER...THE FRONT GETS PUSHED SOUTHEAST AS THE 1045 HP HIGH BUILDS TO THE NORTH. A BRIEF CHANGE TO SNOW IS POSSIBLE BEFORE THE PCPN TOTALLY ENDS...BUT LITTLE TO NO ACCUM IS LIKELY. WITH THE TRACK OF THE MAIN LOW S OF THE AREA AND ONGOING PCPN...GUIDANCE LOOKS TOO WARM FOR TEMPS AND WENT CLOSER TO THE NAM 2M DATA. && .LONG TERM /SUNDAY THROUGH FRIDAY/... PCPN SHOULD BE OVER BY DAYBREAK SUNDAY...WITH CLEARING SKIES AS STRONG ARCTIC HIGH PRESSURE BUILDS TO THE NORTH. SIDED WITH COLDER MET GUIDANCE FOR SUNDAY...WITH HIGHS REMAINING IN THE 30S...AND A BRISK N-NE FLOW KEEPING WIND CHILLS IN THE 20S. MON MAY NOT BE MUCH DIFFERENT AS H8 TEMPS AND H8-10 THICKNESSES REMAIN FAIRLY CONSTANT. ATTENTION THEN TURNS TO THE STORM EXPECTED TO DEVELOP OFF THE EAST COAST BEGINNING MON NIGHT. SIDING MORE AND MORE WITH A MORE AMPLIFIED SOLUTION PER LAST TWO RUNS OF THE ECMWF FOR THIS EVENT... AS AN AMPLIFYING NRN STREAM PHASES WITH A PAIR OF DISTINCT SHORTWAVES MIGRATING FROM THE NRN ROCKIES AND DESERT SW IN SPLIT FLOW ALOFT...AND A WEAK SFC WAVE ALONG A STALLED FRONTAL ZONE OFF THE SE COAST. TREND HAS BEEN FOR THIS LOW TO DEVELOP CLOSER TO THE COAST LATE MON NIGHT TUE MORNING...THEN QUICKLY INTENSIFY OFF THE MID ATLANTIC COAST. LATEST RUNS OF THE ECMWF AND THE 00Z ECMWF ENS MEAN DIVERGE FROM THAT POINT ON...WITH THE OPERATIONAL RUNS TRENDING TOWARD A MORE INTENSE LOW WITH WARM SECLUSION REACHING PEAK INTENSITY TUE NIGHT NEAR THE NY BIGHT...AND THE 00Z ENS MEAN SHOWING A MORE OFFSHORE LOW TRACK. GIVEN THE INCREASING POTENTIAL FOR GREATER PHASING OF THE VARIOUS STREAMS ALOFT...THINK THE OPERATIONAL TREND IS MORE ON TRACK. IN TERMS OF SENSIBLE WX...AN INITIAL SHOT OF WAA PCPN MON NIGHT-TUE MORNING...WITH WARMING TEMPS ALOFT BUT REMAINING COLD AT THE SFC AS THE ARCTIC HIGH DEPARTS...COULD YIELD A PD OF SNOW CHANGING TO MIXED PCPN INLAND...WITH MAINLY RAIN AT THE COAST. THEN AS THE COASTAL LOW WINDS UP...THINK PCPN LATE TUE MORNING INTO TUE AFTERNOON SHOULD BE ALL RAIN...WHICH COULD BE HEAVY AT TIMES GIVEN STRENGTHENING ATLANTIC INFLOW AND COUPLED JET ENERGY. AS THE LOW REACHES PEAK INTENSITY...WOULD EXPECT DYNAMIC COOLING WITH DEVELOPING COMMA HEAD PCPN TO THE NORTH/WEST OF THE SFC LOW TO QUICKLY CHANGE PCPN BACK TO ACCUMULATING SNOW NORTH/WEST OF NYC TUE EVENING AND CONTINUE INTO WED MORNING...WITH SOME POTENTIAL FOR SIGNIFICANT SNOWFALL. FARTHER SOUTH/EAST...A MORE GRADUAL CHANGE TO MIXED PCPN AND THEN LIGHT SNOW FOR NYC METRO...COASTAL SECTIONS AND SE CT FOR LATE TUE NIGHT INTO WED MORNING APPEARS MORE LIKELY. EXACT SFC LOW TRACK AND INTENSITY ARE UNCERTAIN... BUT THERE IS ALSO POTENTIAL FOR A PD OF STRONG E-NE WINDS SOME TIME TUE NIGHT THAT COULD IMPACT COASTAL SECTIONS IF THE LOW TRACKS JUST TO THE SOUTH. WITH THE LOW SLOW TO PULL AWAY...LINGERING SNOW SHOWERS COULD BE AROUND WED INTO WED NIGHT. THEN FAIR AND COLD/BRISK BUT NOT UNSEASONABLY COLD WX EXPECTED FOR THU/FRI. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... LOW PRESSURE WILL APPROACH TONIGHT AND PASS ACROSS THE REGION SATURDAY. MAINLY IFR OVERNIGHT IN RAIN AND FOG. AT TIMES...CEILINGS/VSBYS MAY IMPROVE TO MVFR...OR LOWER TO LIFR BRIEFLY. THE LOW IFR CEILINGS AND/OR VSBYS SHOULD CONTINUE THROUGH THE DAY SATURDAY IN INTERMITTENT RAIN. EASTERLY WINDS LIGHTEN OVERNIGHT...AND MAY BECOME QUITE VARIABLE AS THE FRONT NEARS THE AREA. SOUTH WINDS UNDER 10 KTS ARE EXPECTED LATE SATURDAY MORNING AND INTO THE AFTERNOON BEFORE WINDS SHIFT LATE IN THE DAY TO THE NORTH. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .SAT NIGHT...RAIN ENDS WITH IMPROVEMENT TO VFR AFTER MIDNIGHT. WINDS SHIFT N IN THE EVENING...INCREASING TO 20KT WITH GUSTS 25-30KT. .SUN...VFR. N 20KT GUSTS 25-30KT. .MON...VFR AM. CHC MVFR AND -RA PM. E 10KT. .TUE...MVFR/IFR IN RAIN. NE 10-20KT. CHC GUSTS 25-30KT. .WED...CHC MVFR/IFR IN MIXED PCPN. NW 10-15KT GUSTS 20-25KT. && .MARINE... WINDS DIMINISHING OVERNIGHT...BUT SEAS WILL TAKE A WHILE TO SUBSIDE FROM 5-8 FT THAT`S REPORTED AS OF 9 PM. THUS...SCA CONTINUES INTO THE MORNING. NLY WINDS INCREASE SAT NGT AS LOW PRES PASSES S OF THE WATERS. A GALE WATCH REMAINS IN EFFECT FOR ALL OF THE WATERS EXCEPT FOR THE HARBOR AND WRN SOUND. GALE WATCH RUNS INTO SUNDAY AFTERNOON FOR THE OCEAN WATERS AND THE ERN SOUND/BAYS...WITH GUSTS 35-40 KT POSSIBLE IN N-NE FLOW BETWEEN ARCTIC HIGH PRESSURE TO THE NORTH AND LOW PRESSURE OFF THE SE COAST. GALES COULD LINGER INTO SUNDAY EVENING ON THE OCEAN OUT EAST... OTHERWISE EXPECT SCA CONDS ON ALL WATERS INTO SUNDAY NIGHT/MON MORNING...THEN OCEAN SEAS REMAINING ELEVATED MON INTO MON NIGHT. HAVE FORECAST SCA CONDS FOR TUE-TUE NIGHT WITH THE COASTAL STORM MAINLY ON THE OCEAN...BUT THIS SITUATION IS HIGHLY UNCERTAIN...AND GALES COULD BE POSSIBLE ON ALL WATERS TUE NIGHT IF THE LOW TRACK AND INTENSITY ARE IDEAL. SCA CONDS LIKELY TO LINGER IN NW FLOW ON THE BACK SIDE OF THE SLOWLY DEPARTING LOW WED INTO WED NIGHT. && .HYDROLOGY... UP TO AN INCH AND A HALF OF LIQUID CAN BE EXPECTED THRU SAT NGT. SIGNIFICANT QPF OF 1.5 TO 2 INCHES POSSIBLE WITH A COASTAL STORM...MAINLY FROM LATE MON NIGHT INTO WED MORNING. PART OF THIS SHOULD FALL AS SNOW ESPECIALLY NORTH/WEST OF NYC. NUISANCE HYDROLOGIC IMPACTS POSSIBLE TUE AFTERNOON/EVENING WITH ANY HEAVY RAINFALL. && .TIDES/COASTAL FLOODING... A FULL MOON AND RESIDUAL SURGE WILL PRESENT A VERY LOW PROBABILITY FOR MINOR INUNDATION OF THE MOST VULNERABLE LOCALES ALONG THE SOUTH SHORE BAYS OF WESTERN LI AND NYC DURING THE SAT MORNING HIGH TIDE. THE PROBABILITY IS TOO LOW TO ISSUE A STATEMENT ATTM. A PROLONGED PERIOD OF MODERATELY HIGH EASTERLY SWELLS SUNDAY THROUGH EARLY NEXT WEEK WILL LIKELY RESULT IN EROSION ISSUES ALONG THE BARRIER BEACHES. MINOR COASTAL FLOODING IS ALSO POSSIBLE DURING THE TIME OF HIGHER HIGH TIDES EARLY NEXT WEEK DUE TO A DEVELOPING COASTAL LOW. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST SATURDAY FOR NYZ067. NJ...NONE. MARINE...GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY AFTERNOON FOR ANZ330-340-345-350-353-355. SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR ANZ353-355. SMALL CRAFT ADVISORY UNTIL 1 PM EST SATURDAY FOR ANZ350. && $$ SYNOPSIS...JMC/GOODMAN NEAR TERM...TONGUE SHORT TERM...JMC/TONGUE LONG TERM...GOODMAN AVIATION...PW MARINE...JMC/GOODMAN/TONGUE HYDROLOGY...JMC/GOODMAN TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NWS KEY WEST FL
931 PM EST FRI DEC 5 2014 .DISCUSSION... .CURRENTLY... EASTERLY WINDS HAVE USHERED IN SOME ADDED CLOUD COVER THIS EVENING. THE EVENING SOUNDING SHOWS THE EASTERLY WINDS THROUGH THE 750 MB AN AFTERNOON ASCAT PASS DIRECTLY OVER THE AREA SHOWS A SWATH OF 15 TO 20 KNOTS ACROSS THE STRAITS WHICH IS SUPPORTED BY MARINE OBSERVATION ALONG HAWK CHANNEL. ISLAND LOCATIONS ARE 5 TO 10 KNOTS WHILE MARINE LOCATIONS NORTH OF THE ISLAND CHAIN HAVE MEASURED WINDS AT 10 TO 15 KNOTS. JUST FOUND A RAPIDSCAT PASS ALSO DIRECTLY OVER THE KEYS...AS OF 09 LOCAL...02Z...INDICATING 15 TO 20 KNOTS OVER THE STRAITS. .FORECAST... SHOWERS DEVELOPING IN SPEED CONVERGENCE ACROSS THE AREA AT THIS HOUR...ARE VERY SHALLOW...WILL BE SHORT LIVED...AND WILL PRODUCE UP TO SEVERAL HUNDREDTHS OF AN INCH OF RAINFALL. THESE ARE MOVING AT 15 TO 20 KNOTS ACROSS THE AREA FROM EAST TO WEST. WITH THE MOTION OF THESE SHOWERS AND THE COMBINATION OF THE RECENT OBSERVATIONS INCLUDING ASCAT AND RAPIDSCAT WILL LOWER WINDS SLIGHTLY AHEAD OF SCHEDULE WHICH WILL BE THE ONLY CHANGE IN THE CURRENT FORECAST. THE HIGH RESOLUTION RAPID REFRESH LOCAL MESOSCALE MODEL HAS DONE A VERY GOOD JOB WITH WINDS AND RAINFALL LEADING INTO THE FORECAST SCHEME THIS EVENING SO WILL LEAD MOSTLY ON THE HRRR IN THE SHORT TERM. && .MARINE... WITH THE LOCAL MESO SCALE MODEL WORKING WELL HAVE LOWERED THE SMALL CRAFT ADVISORY ACROSS THE STRAITS...BUT WILL URGE SMALL CRAFT TO EXERCISE CAUTION UNTIL WINDS AND SEAS SUBSIDE FURTHER. OBVIOUSLY...WINDS NORTH OF THE ISLAND CHAIN WILL BE LOWER DUE TO DECOUPLING OF WINDS OVER COOLER WATERS. && .AVIATION... OVERNIGHT...VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS OVERNIGHT. EXPECT SCATTERED CLOUDS WITH BASES AOA FL020-025 AGL. VERY BRIEF MVFR CIGS AND OR VIS WILL BE POSSIBLE WITHIN ISOLATED SHOWERS...BUT DURATION AND PROBABILITY TOO LOW TO INCLUDE IN TAF ATTM. SURFACE WINDS WILL AVERAGE BETWEEN 050-070 DEGREES AOA 10-12 KNOTS. && .CLIMATE... ON THIS DATE IN KEYS WEATHER HISTORY...1876...THE MERCURY DIPPED TO 45 DEGREES IN KEY WEST. THIS SET THE DAILY RECORD MINIMUM TEMPERATURE FOR KEY WEST ON DECEMBER 5TH...WHICH STANDS 138 YEARS LATER. TEMPERATURE RECORDS FOR KEY WEST DATE BACK TO 1872. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...NONE. GM...NONE. && $$ PUBLIC/MARINE.........BWC AVIATION/NOWCASTS.....FUTTERMAN DATA COLLECTION.......CHESSER VISIT US ON THE WEB AT WEATHER.GOV/KEY FOLLOW US ON FACEBOOK AND TWITTER AT... WWW.FACEBOOK.COM/NWSKEYWEST WWW.TWITTER.COM/NWSKEYWEST
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
833 PM EST FRI DEC 5 2014 ...MILD AND FOGGY TONIGHT WITH A FEW LIGHT SHOWERS... .UPDATE...YET ANOTHER COASTAL TROUGH HAS FORMED OFFSHORE OF THE FIRST COAST AGAIN ONLY DEPICTED WELL BY THE NAM12 WHICH SHOWED A STRONG NNE WIND GRADIENT DOWN THE LOCAL SEABOARD. SEA FOG CONTINUED TO IMPACT OUR COASTAL SITES...WITH SOME INLAND PROGRESSION OVER THE ESTUARIES. THE HRRR MODEL CONTINUED TO SUGGEST THE SEA FOG DRIFTING INLAND OVERNIGHT...BUT GIVEN ELEVATED WINDS OF NEAR 15 KTS ABOVE THE SURFACE AND SOME SHALLOW ISENTROPIC LIFT AS EVIDENCED BY A FEW PATCHES SPRINKLES DRIFTING NWD OVER MARION COUNTY...WILL CONTINUE TO HANDLE PATCHY DENSE FOG ALONG THE COAST AND THAT FORMS INLAND THROUGH THIS EVENING WITH A SPECIAL WEATHER STATEMENT IN LIEU OF AN ADVISORY DUE TO LOWER CONFIDENCE. THE PRESENCE OF THE ELEVATED BOUNDARY LAYER WINDS AND PASSING MID/HIGH CLOUDS AGAIN MAKE FOR LESS THAN IDEAL PERSISTENT DENSE FOG CONDITIONS. HIGH CLOUDS WILL BEGIN TO CLEAR OUT FROM THE WNW LATE TONIGHT/EARLY SAT MORNING...WITH PERHAPS VSBYS DROPPING INLAND DUE TO BETTER RADIATIONAL COOLING CONDITIONS. TEMPS WILL BE MILD AND RANGE FROM MINS IN THE LOWER 60S COAST TO THE MID 50S WELL INLAND UNDER CLOUDY TO PARTLY CLOUDY SKIES. && .AVIATION...EXPECT SEA FOG TO PERSIST TONIGHT AS IT SPREADS INLAND. CURRENTLY VLIFR CONDITIONS AT JAX AND CRG WITH LIFR AT VQQ. EXPECT SSI AND GNV TO ALSO GO DOWN TO LIFR BY 06Z. EXPECT CONDITIONS TO SLOWLY IMPROVE AROUND 14-15Z TO MVFR AND THEN IFR BY 17Z AS WINDS BECOME OFFSHORE ON SATURDAY. && .MARINE...SEA DENSE FOG CONTINUED TO AFFECT THE NEAR SHORE WATERS WITH RECENT REPORTS STATING DENSE FOG LESSENED ALONG THE FLAGLER COUNTY COAST. WILL CONTINUE TO LEAVE THE CURRENT MARINE DENSE FOG ADVISORY IN PLACE FOR THE NEAR SHORE WATERS...BUT AS THE COASTAL TROUGH WEAKENS OVERNIGHT AND MORE MIXING APPROACHES AT LEAST OUR SOUTHERN NEAR SHORE WATERS...THE ADVISORY MAY NEED TO BE TRIMMED NORTHWARD FOR ONLY OUR NEAR SHORE ZONES N OF ST AUGUSTINE. AROUND 830 PM...FERNANDINA BEACH REPORT 1/2 SM...MAYPORT REPORTED 1/4 SM...ST AUGUSTINE WAS 1 1/2 SM...AND ST SIMONS ISLAND WAS 8 SM BUT STILL BLANKETED WITH LOW STRATUS. THE NAM12 HAD THE BEST HANDLE ON THE STRENGTH OF THE COASTAL TROUGH THIS EVENING WITH ELEVATED NNE WINDS 15-20 KTS ALONG THE IMMEDIATE COASTLINE DUE TO THE PINCHED PRESSURE GRADIENT. WILL CONTINUE TO LEAN TOWARD THIS SOLUTION TONIGHT WHICH WILL BRING SMALL CRAFT EXERCISE CAUTION CONDITIONS FOR THE NEAR SHORE WATERS THIS EVENING...AND THE OFFSHORE WATERS DUE TO LINGERING ELEVATED SEAS OF 5-6 FT. WINDS/SEAS WILL RELAX LATE TONIGHT/EARLY SAT MORNING AS WEAK HIGH PRESSURE SETTLES OVER THE WATERS AND WINDS BECOME VARIABLE 10 KTS OR LESS. WINDS INCREASE SUN TRAILING A DRY COLD FRONTAL PASSAGE WITH SMALL CRAFT ADVISORY CONDITIONS ANTICIPATED FOR THE OFFSHORE WATERS INTO TUESDAY. RIP CURRENTS: LOW RISK EXPECTED ON SATURDAY DUE TO LIGHT WINDS. && .PRELIMINARY POINT TEMPS/POPS... AMG 56 75 52 66 / 10 20 20 10 SSI 58 72 55 64 / 10 10 10 10 JAX 59 76 55 67 / 10 10 10 10 SGJ 61 74 58 67 / 10 10 10 10 GNV 58 78 56 71 / 20 10 10 10 OCF 58 79 57 73 / 20 10 10 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...DENSE FOG ADVISORY UNTIL 10 AM EST SATURDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ ENYEDI/ZIBURA/GUILLET
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
330 PM EST THU DEC 4 2014 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UNAMPLIFIED UPPER LEVEL PATTERN ACROSS THE CONUS. FLOW IS MAINLY ZONAL AND PROGRESSIVE IN NATURE...INCLUDING ACROSS THE NORTHERN GULF AND FLORIDA PENINSULA. DO SEE A WEAK SHORTWAVE TROUGH MOVING ASHORE ACROSS THE BAJA REGION/SW STATES. THIS ENERGY WILL MAKE ITS WAY ACROSS THE DEEP SOUTH...BUT HAVE NO IMPACT ON OUR LOCAL WEATHER THROUGH THE DURATION OF THE UPCOMING WEEKEND. 04/12Z KTBW SOUNDING SHOWS A VERY DRY COLUMN IN THE MID-LEVELS 700-500MB...HOWEVER THE DEPTH OF THE DRY LAYER HAS BEEN DIMINISHED SINCE WEDNESDAY EVENING...WITH CONSIDERABLY MORE MOISTURE ABOVE 500MB. LOOKING AT WV THIS SINCE THIS MORNING...IT IS LIKELY THAT THIS HIGHER MOISTURE IN THE UPPER LEVELS HAS EXITED OFF TO THE EAST AND THE EVENING SOUNDING SHOULD COME IN DRIER ONCE AGAIN. AT THE SURFACE...HIGH PRESSURE CENTERED OVER THE NORTHEASTERN STATES RIDGES ALL THE WAY DOWN THE EASTERN SEABOARD TO THE EASTERN GULF/FL PENINSULA...PROVIDING OUR REGION WITH A SYNOPTIC LOW LEVEL FLOW FROM THE NORTHEAST. LOWER LEVELS MIXED TO AROUND 5000 FEET ON WEDNESDAY...AND EXPECT SIMILAR CONDITIONS TO END OUT TODAY. BASED ON THE MORNING SOUNDING...A BOUNDARY LAYER THIS HIGH SHOULD MIX OUT OUR AFTERNOON TEMPS INTO THE UPPER 70S AND LOWER 80S. CROSS-SECTIONAL ANALYSIS WHICH SHOWED DECENT MOISTURE UNDER 700MB SEEMS TO BE RIGHT AS IT IS SUPPORTING A SCT SHALLOW CUMULUS FIELD UNDERNEATH THE DRY MID-LEVELS. SIMILAR TO PREVIOUS DAYS...THE ONSHORE SPEED CONVERGENCE FLOW ALONG THE EAST COAST ALONG WITH DIURNAL HEATING IS SUPPORTING A FEW LIGHT SHOWERS/SPRINKLES MIGRATING INTO OUR COUNTIES FROM THE EAST THROUGH THE AFTERNOON HOURS. LOW LEVEL MOISTURE IS SLIGHTLY DEEPER TO THE SOUTH OF I-4...AND THIS IS WHERE THE MAJORITY OF THE SPRINKLES WILL REMAIN THROUGH THE EARLY EVENING HOURS BEFORE ACTIVITY DISSIPATES. ANY RAINFALL SHOULD HAVE A VERY LIMITED IMPACT ON OUTDOOR ACTIVITIES. && .SHORT TERM (TONIGHT AND FRIDAY)... SREF ENSEMBLE GUIDANCE (WHICH DID A VERY GOOD JOB WITH THE LOWER CLOUD/FOG AREAS THIS PAST MORNING) IS STRONGLY SHOWING ANOTHER LOWER STRATUS/FOG EVENT BUILDING DOWN TO AROUND (OR JUST NORTH) THE I-4 CORRIDOR DURING THE SECOND HALF OF TONIGHT / EARLY FRIDAY MORNING. THE STATISTICAL MOS IS ALSO FAIRLY AGGRESSIVE AT OUR NORTHERN STATIONS. ALWAYS DIFFICULT TO DETERMINE IF THESE EVENTS WILL BE DENSE FOG...OR JUST A VERY LOW STRATUS DECK AT 2-5 HUNDRED FEET ABOVE THE GROUND. THIS PAST MORNING TENDED TO BE MORE OF A STRATUS EVENT OVER OUR ZONES...BUT WAS MORE OF A FOG EVENT FURTHER NORTH. SINCE THE WHOLE PATTERN IS SHIFTING SOUTHWARD A BIT FOR TONIGHT... HAVE DECIDED TO EXPAND THE FOG AREAS IN THE CURRENT FORECAST GRIDS AND ADDED SOME WORDING OF POTENTIAL DENSE FOG (FROM AROUND BROOKSVILLE NORTHWARD) AS WE APPROACH DAWN FRIDAY MORNING. THE GRADIENT MAY HOLD UP JUST ENOUGH TO KEEP THIS ANOTHER MAINLY STRATUS EVENT...BUT JUST TOO CLOSE TO CALL. SOMETHING TO KEEP IN MIND IF HEADING OUT EARLY FRIDAY MORNING FROM HILLSBOROUGH AND POLK COUNTIES NORTHWARD THROUGH THE NATURE COAST. IN TERMS OF TEMPERATURES... EXPECTING SEASONABLE READINGS OF MID/UPPER 50S NORTH...AND LOWER TO MIDDLE 60S FROM THE I-4 CORRIDOR SOUTHWARD. FRIDAY... WEAK RIDGING OVER THE SOUTHERN GULF OF MEXICO IS FORECAST TO EXPAND NORTHWARD INTO THE EASTERN GULF AND OVER THE FLORIDA PENINSULA DURING THE DAYLIGHT HOURS. THIS WILL ONLY HAVE A SLIGHT EFFECT OF TURNING OUR FLOW ALOFT FROM ZONAL TO MORE ANTI-CYCLONIC IN NATURE. THE BUILDING HEIGHTS SHOULD ALSO ALLOW TEMPERATURES TO WARM ANOTHER DEGREE OR 2 FROM FRIDAY. SURFACE RIDGE WILL CONTINUE TO BUILD DOWN THE EASTERN SEABOARD AND THE GRADIENT LOOKS TIGHT ENOUGH TO SUPPORTS SOME BREEZY CONDITIONS FOR THE LATE MORNING/AFTERNOON HOURS. MOST LOCATIONS SHOULD WARM UP TO MID-AFTERNOON READINGS IN THE UPPER 70S FAR NORTH...TO LOWER 80S CENTRAL ZONES...AND LOWER/MID 80S DOWN TOWARD PUNTA GORDA AND FORT MYERS. SIMILAR TO FRIDAY...JUST THE OUTSIDE CHANCE OF A FEW ISOLATED SHOWERS/SPRINKLES MIGRATING WESTWARD ACROSS THE PENINSULA DURING THE AFTERNOON FROM THE I-4 CORRIDOR SOUTHWARD. SPRINKLES SHOULD NOT HAVE MUCH IMPACT ON OUTDOOR PLANS/ACTIVITIES. HAVE A GREAT EVENING EVERYONE! && .LONG TERM (SATURDAY THROUGH NEXT THURSDAY)... MODELS IN FAIR AGREEMENT WITH THE SURFACE FEATURES WHILE SOME SLIGHT DIFFERENCES IN UPPER LEVELS. WILL EXPECT MAINLY WARM...DRY AND HUMID CONDITIONS THROUGH SATURDAY. WEAK COLD FRONT TO MOVE OVER THE REGION SUNDAY WITH ONLY A SLIGHT CHANCE OF RAIN ASSOCIATED WITH THE FRONT AND DROPPING TEMPERATURES TO AROUND SEASON NORMS TO END THE WEEKEND. COOLER HIGH PRESSURE BUILDS DOWN THE EASTERN SEABOARD EARLY NEXT WEEK KEEPING COOL AND MAINLY DRY CONDITIONS IN PLACE. RE-ENFORCING HIGH PRESSURE TO BUILD INTO THE REGION BY MID WEEK ON NORTHEASTERLY LOW LEVEL FLOW. NEXT WEEKS TEMPERATURES EXPECTED TO BE NEAR TO SLIGHTLY BELOW NORMAL THROUGH THE PERIOD. && .AVIATION... VFR CONDITIONS PREVAILING ACROSS THE REGION THIS AFTERNOON AND WILL CONTINUE THROUGH THE EVENING HOURS. LARGE AREA OF IFR STRATUS/AND OR FOG IS ANTICIPATED TO DEVELOP OVER NORTHERN FLORIDA AND EXTEND DOWN TO NEAR KTPA/LAL. GUIDANCE CONSENSUS IS THAT THE MAIN AREA OF RESTRICTIONS STAY NORTH OF THESE TERMINALS...SO FOR NOW WILL LEAVE OUT OF TAFS...HOWEVER SITUATION/GUIDANCE WILL NEED TO BE WATCHED CLOSELY AS CIGS/VIS RESTRICTIONS WILL NEED TO BE ADDED TO THESE NORTHERN TERMINALS SHOULD THINGS SHIFT SOUTH. ANY MORNING RESTRICTIONS WILL BURN OFF BY 14-15Z WITH VFR CONDITIONS THEN PREVAILING FOR THE REMAINDER OF FRIDAY. && .MARINE... THE EASTERN GULF OF MEXICO WILL REMAIN ON THE SOUTHERN FRINGE OF A LARGE SURFACE HIGH PRESSURE SYSTEM CENTERED WELL NORTH OF THE REGION. OFF SHORE WINDS WILL PREVAIL OVER THE NEXT COUPLE OF DAYS WITH A NOCTURNAL SURGE DEVELOPING EARLY FRIDAY MORNING INCREASING WINDS TO AROUND 15 KT IN THE OFF SHORE WATERS. A WEAK SURFACE BOUNDARY WILL LINGER IN THE VICINITY OF PENINSULA OVER THE WEEKEND BUT WILL NOT PRODUCE ANY SIGNIFICANT CHANGES IN THE PATTERN. && .FIRE WEATHER... HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THE EASTERN SEABOARD INTO THE REGION THROUGH THE DAY ON FRIDAY. THIS RIDGE WILL BRIEFLY BREAK DOWN ON SATURDAY AS A COLD FRONT APPROACHES AND PASSES TROUGH THE REGION SATURDAY NIGHT AND SUNDAY. A NEW RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD INTO THE REGION FOR THE EARLY PORTION OF NEXT WEEK. RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE CRITICAL LEVELS THE NEXT SEVERAL DAYS...AND OTHER THAN AREAS OF HIGH DISPERSION INDICES FRIDAY AFTERNOON...NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH SATURDAY. FOG POTENTIAL...AREAS OF LOW STRATUS AND FOG ARE EXPECTED EARLY FRIDAY MORNING...ESPECIALLY NORTH OF THE I-4 CORRIDOR. THIS LOW CLOUD AND FOG SHOULD BURN OFF DURING THE MIDDLE MORNING HOURS. && .PRELIMINARY POINT TEMPS/POPS... TPA 65 80 65 79 / 0 20 10 20 FMY 65 83 66 82 / 10 20 10 10 GIF 63 81 62 80 / 10 20 0 20 SRQ 64 81 64 79 / 0 10 0 10 BKV 59 81 59 80 / 0 10 0 20 SPG 66 79 65 78 / 0 10 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/FIRE WEATHER...MROCZKA MARINE...BARRON LONG TERM...DAVIS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1040 AM EST THU DEC 4 2014 .UPDATE (REST OF TODAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UNAMPLIFIED UPPER LEVEL PATTERN ACROSS THE CONUS. FLOW IS MAINLY ZONAL AND PROGRESSIVE IN NATURE...INCLUDING ACROSS THE NORTHERN GULF AND FLORIDA PENINSULA. DO SEE A WEAK SHORTWAVE TROUGH MOVING ASHORE ACROSS THE BAJA REGION/SW STATES. THIS ENERGY WILL MAKE ITS WAY ACROSS THE DEEP SOUTH...BUT HAVE NO IMPACT ON OUR LOCAL WEATHER THROUGH THE DURATION OF THE UPCOMING WEEKEND. 04/12Z KTBW SOUNDING SHOWS A VERY DRY COLUMN IN THE MID-LEVELS 700-500MB...HOWEVER THE DEPTH OF THE DRY LAYER HAS BEEN DIMINISHED SINCE WEDNESDAY EVENING...WITH CONSIDERABLY MORE MOISTURE ABOVE 500MB. LOOKING AT WV THIS MORNING...IT IS LIKELY THAT THIS HIGHER MOISTURE IN THE UPPER LEVELS IS NOW EXITING OFF TO THE EAST AND THE EVENING SOUNDING WILL COME IN DRIER ONCE AGAIN. EARLIER UPPER LEVEL CLOUDS ASSOCIATED WITH THIS MOISTURE HAVE MIGRATED OFF TO OUR EAST LEAVING MOSTLY CLEAR SKIES AND PLENTY OF SUNSHINE TO WARM US UP. AT THE SURFACE...HIGH PRESSURE CENTERED OVER THE NORTHEASTERN STATES RIDGES ALL THE WAY DOWN THE EASTERN SEABOARD TO THE EASTERN GULF/FL PENINSULA...PROVIDING OUR REGION WITH A SYNOPTIC LOW LEVEL FLOW FROM THE NORTHEAST. EXTENSIVE LOWER STRATUS/FOG UNDER THE NOCTURNAL INVERSION THAT FORMED OVERNIGHT TO THE NORTH OF THE I-4 CORRIDOR WAS UNDER 1000 FEET THICK AND HAS BURNED OFF QUICKLY IN THE PAST FEW HOURS. LATEST VISIBLE SATELLITE IMAGERY SHOWS NO SIGNS LEFT OF THIS EARLIER OVERCAST/FOG. HOWEVER...ALL INDICATIONS ARE THAT IT WILL BE RETURNING TO THE NORTHERN HALF OF THE PENINSULA DURING THE SECOND HALF OF TONIGHT. TEMPERATURES HAVE REBOUNDED INTO THE 70S AT ALL LOCATIONS THIS MID-MORNING. LOWER LEVELS MIXED TO AROUND 5000 FEET ON WEDNESDAY...AND EXPECT SIMILAR CONDITIONS FOR TODAY. BASED ON THE MORNING SOUNDING...A BOUNDARY LAYER THIS HIGH SHOULD MIX OUT OUR AFTERNOON TEMPS INTO THE MID/UPPER 70S NORTH AND LOWER 80S SOUTH. CROSS-SECTIONAL ANALYSIS SHOWS ENOUGH MOISTURE UNDER 700MB TO SUPPORT A FEW-SCT SHALLOW CUMULUS FIELD DEVELOPING THROUGH THE DAY UNDERNEATH THE DRY MID-LEVELS. SIMILAR TO PREVIOUS DAYS...THE ONSHORE SPEED CONVERGENCE FLOW ALONG THE EAST COAST ALONG WITH DIURNAL HEATING SHOULD BE ENOUGH TO SUPPORT A FEW LIGHT SHOWERS/SPRINKLES MIGRATING INTO OUR COUNTIES FROM THE EAST THROUGH THE AFTERNOON HOURS. LOW LEVEL MOISTURE IS SLIGHTLY DEEPER TO THE SOUTH OF I-4...AND WILL RUN THE BEST CHANCE OF A BRIEF SHOWER OVER THESE SOUTHERN ZONES. JUST RUNNING A 20% PROB OF SEEING A SHOWER...AND ANY RAINFALL SHOULD HAVE A VERY LIMITED IMPACT ON ANY OUTDOOR ACTIVITIES. AS MENTIONED ABOVE...SREF ENSEMBLE GUIDANCE (WHICH DID A VERY GOOD JOB WITH THE LOWER CLOUD/FOG AREAS THIS PAST MORNING) IS STRONGLY SHOWING ANOTHER LOWER STRATUS/FOG EVENT BUILDING DOWN TO AROUND THE I-4 CORRIDOR DURING THE SECOND HALF OF TONIGHT / EARLY FRIDAY MORNING. THE STATISTICAL MOS IS ALSO FAIRLY AGGRESSIVE AT OUR NORTHERN STATIONS. ALWAYS DIFFICULT TO DETERMINE IF THESE EVENTS WILL BE DENSE FOG...OR JUST A VERY LOW STRATUS DECK AT 2-5 HUNDRED FEET ABOVE THE GROUND. THIS PAST MORNING TENDED TO BE MORE OF A STRATUS EVENT OVER OUR ZONES...BUT WAS MORE OF A FOG EVENT FURTHER NORTH. SINCE THE WHOLE PATTERN IS SHIFTING SOUTHWARD A BIT FOR TONIGHT... HAVE DECIDED TO EXPAND THE FOG AREAS IN THE CURRENT FORECAST GRIDS AND ADDED SOME WORDING OF POTENTIAL DENSE FOG (FROM AROUND BROOKSVILLE NORTHWARD) AS WE APPROACH DAWN FRIDAY MORNING. JUST SOMETHING TO KEEP IN MIND IF HEADING OUT EARLY FRIDAY MORNING FROM HILLSBOROUGH AND POLK COUNTIES NORTHWARD THROUGH THE NATURE COAST. HAVE A GREAT REMAINDER OF YOUR THURSDAY! && .AVIATION... VFR CONDITIONS NOW PREVAIL ACROSS THE REGION. EARLY STRATUS/FOG ALONG AND NORTH OF THE I-4 CORRIDOR HAS QUICKLY BURNED OFF. THE REMAINDER OF THE DAY LOOKS BENIGN WITH LIGHT NORTHEAST WINDS AND A DEVELOPING FEW-SCT CUMULUS FIELD. ENSEMBLE AND STATISTICAL GUIDANCE IN AGREEMENT OF ANOTHER ROUND OF STRATUS/FOG ALONG AND NORTH OF THE I-4 CORRIDOR. WILL EVALUATE THIS THREAT FURTHER WITH THE NEXT GUIDANCE PACKAGE TO DETERMINE ANY EARLY MENTION FOR KTPA/KLAL/KPIE WHO CURRENTLY LOOK TO SEE THE BEST CHANCES FOR ANY SIGNIFICANT EARLY MORNING RESTRICTIONS. SIMILAR TO TODAY...EARLY MORNING RESTRICTIONS SHOULD QUICKLY END BY AROUND 15Z...FOLLOWED BY PREVAILING VFR CONDITIONS FOR THE REMAINDER OF YOUR FRIDAY. && .MARINE... THE EASTERN GULF OF MEXICO WILL REMAIN ON THE SOUTHERN FRINGE OF A LARGE SURFACE HIGH PRESSURE SYSTEM CENTERED WELL NORTH OF THE REGION. OFF SHORE WINDS WILL PREVAIL OVER THE NEXT COUPLE OF DAYS WITH A NOCTURNAL SURGE DEVELOPING EARLY FRIDAY MORNING INCREASING WINDS TO AROUND 15 KT IN THE OFF SHORE WATERS. A WEAK SURFACE BOUNDARY WILL LINGER IN THE VICINITY OF PENINSULA OVER THE WEEKEND BUT WILL NOT PRODUCE ANY SIGNIFICANT CHANGES IN THE PATTERN. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 65 79 65 / 0 0 20 0 FMY 80 65 82 66 / 20 10 10 0 GIF 77 63 78 62 / 10 10 20 0 SRQ 80 65 80 65 / 10 0 20 10 BKV 78 61 79 61 / 0 0 10 0 SPG 77 66 77 66 / 0 0 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION...MROCZKA MARINE...BARRON
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1031 PM EST FRI DEC 5 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL WEAKEN AHEAD OF THE APPROACHING COLD FRONT. THE FRONT WILL MOVE THROUGH THE AREA SATURDAY EVENING. DRYING BEHIND THE FRONT WILL DOMINATE SUNDAY BUT MOISTURE MAY SPREAD BACK INTO THE REGION MONDAY ASSOCIATED WITH LOW PRESSURE DEVELOPING OFF THE COAST. && .NEAR TERM /THROUGH TONIGHT/... HIGH PRESSURE EXTENDING INTO THE FORECAST AREA FROM THE NORTH WILL WEAKEN OVERNIGHT. HIGH LOW- LEVEL MOISTURE AND WEAK ISENTROPIC LIFT PLUS NOCTURNAL COOLING COULD PRODUCE SOME AREAS OF STRATUS ACROSS THE EASTERN PORTION OF THE CWA PER THE EVENING HRRR. OTHERWISE MAINLY MID/HIGH CLOUDS ACROSS THE AREA. MOISTURE IS INITIALLY LOW WITH PW VALUES AROUND 0.75 INCHES BUT INCREASE OVERNIGHT AND INTO SATURDAY TO AROUND 1.0 INCH. MODELS INDICATE INCREASING ISENTROPIC LIFT FROM WEST/SOUTHWEST OVERNIGHT AND INTO SATURDAY. CURRENT RADAR ACROSS THE SOUTHEAST/MID MS RIVER VALLEY SHOWS SHOWERS/THUNDERSTORMS ACROSS MS/AL/TN WHERE BEST ISENTROPIC /MID-UPPER LEVEL FORCING OCCURRING. THIS WILL SHIFT EASTWARD INTO SATURDAY. FORECASTED POPS FOR THE NORTHWESTERN PORTION OF THE CWA LATE TONIGHT AND THEN MOVING INTO THE MIDLANDS BY SATURDAY MORNING. CLOUDINESS SHOULD HELP HOLD UP TEMPERATURES. THE MAV AND MET MOS WERE CLOSE WITH LOWS IN THE UPPER 40S TO AROUND 50. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... MOISTURE WILL INCREASE AHEAD OF THE COLD FRONT SATURDAY. THE NAM WAS STILL A LITTLE SLOWER COMPARED TO THE GFS WITH THE PLACEMENT OF DEEPEST MOISTURE AHEAD OF THE FRONT. USED AN AVERAGE OF THE GUIDANCE FOR THE TIMING OF HIGHEST POPS. STRONGER UPPER-LEVEL LIFT AND DEEPER MOISTURE SUPPORTED THE HIGHEST POPS IN THE NORTH PART OF THE FORECAST AREA. USED THE GUIDANCE CONSENSUS WITH CHANCE POPS SOUTH AND LIKELY NORTH. A THUNDERSTORM IS NOT OUT OF THE QUESTION BECAUSE OF COOLING ALOFT AHEAD OF THE SHORTWAVE TROUGH AND AN H5 DIFLUENT PATTERN PLUS LOW-LEVEL WARMING AHEAD OF THE FRONT. HOWEVER...THE MODEL FORECAST SOUNDINGS HAD LITTLE CAPE AND LIGHTNING WAS NOT EVIDENT UPSTREAM. BELIEVE THE THUNDERSTORM CHANCE IS TOO LOW TO INCLUDE IN THE FORECAST AT THIS TIME. THE TEMPERATURE GUIDANCE WAS CLOSE SATURDAY BUT MAY BE A LITTLE TOO COOL JUST AHEAD OF THE COLD FRONT. DRYING SHOULD OCCUR BEHIND THE FRONT SATURDAY NIGHT AND THE MODELS HAVE BEEN CONSISTENT SHOWING DRY CONDITIONS CONTINUING SUNDAY. THE PRESSURE GRADIENT BETWEEN THE RIDGE TO THE NORTHWEST AND OFFSHORE FRONT WILL LIKELY RESULT IN BREEZY CONDITIONS SUNDAY. THE NAM MOS HAD LESS WIND COMPARED TO THE GFS MOS. WE LEANED TOWARD MORE WIND BASED ON THE EXPECTED GRADIENT. && .LONG TERM /MONDAY THROUGH FRIDAY/... THE MODELS HAVE TRENDED BACK TO MORE MOISTURE MONDAY ASSOCIATED WITH LOW PRESSURE DEVELOPING OFF THE SOUTHEAST COAST. THIS MOISTURE APPEARS DEEPEST IN THE NORTHEAST SECTION. THE GFS AND ECMWF MOS POPS WERE NEAR 30 PERCENT. THE LOW SHOULD BE FARTHER NORTHEAST OF THE AREA TUESDAY WITH DRY RIDGING DOMINATE DURING THE REST OF THE MEDIUM-RANGE PERIOD. CLOUDINESS AND A NORTHEAST FLOW WILL LIKELY HOLD DOWN HIGH TEMPERATURES MONDAY. THE GFS AND ECWMF MOS HAVE TRENDED COOLER AND MAY STILL BE TOO WARM. STRONG NOCTURNAL COOLING WITH THE RIDGE NEAR THE AREA SHOULD RESULT IN COLD LOW TEMPERATURES WEDNESDAY THROUGH FRIDAY. THE GFS AND ECMWF MOS HAVE LOWS IN THE UPPER 20S AND LOWER 30S. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... SURFACE RIDGE CONTINUES TO WEAKEN AS LOW PRESSURE DEVELOPS IN THE MID MISSISSIPPI VALLEY. LOWER CLOUDS THAT BLANKETED THE AREA THIS AFTERNOON HAVE SHIFTED TO THE WEST AND SOUTHWEST WITH VFR CONDITIONS AT ALL BUT DNL WHERE THE LOW CLOUDS CONTINUE TO LINGER. MOS GUIDANCE AND MODEL OUTPUT IS SUGGESTING THAT LOW CLOUDS WILL RETURN TO THE TERMINALS LATER TONIGHT WHILE THE LATEST HRRR MODEL IS KEEPING THE LOWER CLOUDS OFF TO THE SOUTHWEST. WILL FORECAST MVFR CIGS TO RETURN NORTHWARD GIVEN THE SATURATED LOW LEVELS OF FORECAST SOUNDINGS AND THE PERSISTENCE OF LOW CLOUDS FOR THE PAST SEVERAL DAYS. SREF PROBABILITIES OF IFR CIGS ARE HIGH IN THE CSRA BY 08Z-10Z AND AT CAE/CUB AFTER 12Z BEFORE CIGS IMPROVE TO MVFR LATE MORNING INTO EARLY AFTERNOON AS SOUTHERLY FLOW DEVELOPS AHEAD OF THE APPROACHING COLD FRONT. CHANCES FOR SHOWERS WILL INCREASE DURING THE AFTERNOON BUT CONFIDENCE IS LOW IN TERMINALS BEING IMPACTED BY THE SHOWERS AT THIS TIME SO NOT INCLUDED IN THIS FORECAST. EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS POSSIBLE SUNDAY. RESTRICTIONS POSSIBLE AGAIN LATE SUNDAY NIGHT AND MONDAY WITH POSSIBLE WEDGE CONDITIONS DEVELOPING. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030. GA...NONE. && $$ 77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
653 PM EST FRI DEC 5 2014 .SYNOPSIS... HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL WEAKEN AHEAD OF THE APPROACHING COLD FRONT. THE FRONT WILL MOVE THROUGH THE AREA SATURDAY EVENING. DRYING BEHIND THE FRONT WILL DOMINATE SUNDAY BUT MOISTURE MAY SPREAD BACK INTO THE REGION MONDAY ASSOCIATED WITH LOW PRESSURE DEVELOPING OFF THE COAST. && .NEAR TERM /THROUGH SATURDAY/... HIGH PRESSURE EXTENDING INTO THE FORECAST AREA FROM THE NORTH WILL WEAKEN OVERNIGHT. HIGH LOW-LEVEL MOISTURE AND WEAK ISENTROPIC LIFT PLUS NOCTURNAL COOLING SHOULD RESULT IN AREAS OF STRATUS AND FOG. AT THIS TIME...NOT SURE HOW WIDESPREAD...BUT PLENTY OF MID/HIGH CLOUDS MOVING ACROSS THE AREA. MOISTURE SHOULD REMAIN SHALLOW FOR THE MOST PART LIMITING THE RAIN CHANCE...EXCEPT MOISTURE MAY INCREASE LATE IN THE NORTHWEST SECTION ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH. FORECASTED CHANCE POPS IN THE NORTHWEST SECTION. CLOUDINESS SHOULD HELP HOLD UP TEMPERATURES. THE MAV AND MET MOS WERE CLOSE WITH LOWS IN THE UPPER 40S TO AROUND 50. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... MOISTURE WILL INCREASE AHEAD OF THE COLD FRONT SATURDAY. THE NAM WAS STILL A LITTLE SLOWER COMPARED TO THE GFS WITH THE PLACEMENT OF DEEPEST MOISTURE AHEAD OF THE FRONT. USED AN AVERAGE OF THE GUIDANCE FOR THE TIMING OF HIGHEST POPS. STRONGER UPPER-LEVEL LIFT AND DEEPER MOISTURE SUPPORTED THE HIGHEST POPS IN THE NORTH PART OF THE FORECAST AREA. USED THE GUIDANCE CONSENSUS WITH CHANCE POPS SOUTH AND LIKELY NORTH. A THUNDERSTORM IS NOT OUT OF THE QUESTION BECAUSE OF COOLING ALOFT AHEAD OF THE SHORTWAVE TROUGH AND AN H5 DIFLUENT PATTERN PLUS LOW-LEVEL WARMING AHEAD OF THE FRONT. HOWEVER...THE MODEL FORECAST SOUNDINGS HAD LITTLE CAPE AND LIGHTNING WAS NOT EVIDENT UPSTREAM. BELIEVE THE THUNDERSTORM CHANCE IS TOO LOW TO INCLUDE IN THE FORECAST AT THIS TIME. THE TEMPERATURE GUIDANCE WAS CLOSE SATURDAY BUT MAY BE A LITTLE TOO COOL JUST AHEAD OF THE COLD FRONT. DRYING SHOULD OCCUR BEHIND THE FRONT SATURDAY NIGHT AND THE MODELS HAVE BEEN CONSISTENT SHOWING DRY CONDITIONS CONTINUING SUNDAY. THE PRESSURE GRADIENT BETWEEN THE RIDGE TO THE NORTHWEST AND OFFSHORE FRONT WILL LIKELY RESULT IN BREEZY CONDITIONS SUNDAY. THE NAM MOS HAD LESS WIND COMPARED TO THE GFS MOS. WE LEANED TOWARD MORE WIND BASED ON THE EXPECTED GRADIENT. && .LONG TERM /MONDAY THROUGH FRIDAY/... THE MODELS HAVE TRENDED BACK TO MORE MOISTURE MONDAY ASSOCIATED WITH LOW PRESSURE DEVELOPING OFF THE SOUTHEAST COAST. THIS MOISTURE APPEARS DEEPEST IN THE NORTHEAST SECTION. THE GFS AND ECMWF MOS POPS WERE NEAR 30 PERCENT. THE LOW SHOULD BE FARTHER NORTHEAST OF THE AREA TUESDAY WITH DRY RIDGING DOMINATE DURING THE REST OF THE MEDIUM-RANGE PERIOD. CLOUDINESS AND A NORTHEAST FLOW WILL LIKELY HOLD DOWN HIGH TEMPERATURES MONDAY. THE GFS AND ECWMF MOS HAVE TRENDED COOLER AND MAY STILL BE TOO WARM. STRONG NOCTURNAL COOLING WITH THE RIDGE NEAR THE AREA SHOULD RESULT IN COLD LOW TEMPERATURES WEDNESDAY THROUGH FRIDAY. THE GFS AND ECMWF MOS HAVE LOWS IN THE UPPER 20S AND LOWER 30S. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... SURFACE RIDGE CONTINUES TO WEAKEN AS LOW PRESSURE DEVELOPS IN THE MID MISSISSIPPI VALLEY. LOWER CLOUDS THAT BLANKETED THE AREA THIS AFTERNOON HAVE SHIFTED TO THE WEST AND SOUTHWEST WITH VFR CONDITIONS AT ALL BUT DNL WHERE THE LOW CLOUDS CONTINUE TO LINGER. MOS GUIDANCE AND MODEL OUTPUT IS SUGGESTING THAT LOW CLOUDS WILL RETURN TO THE TERMINALS LATER TONIGHT WHILE THE LATEST HRRR MODEL IS KEEPING THE LOWER CLOUDS OFF TO THE SOUTHWEST. WILL FORECAST MVFR CIGS TO RETURN NORTHWARD GIVEN THE SATURATED LOW LEVELS OF FORECAST SOUNDINGS AND THE PERSISTENCE OF LOW CLOUDS FOR THE PAST SEVERAL DAYS. SREF PROBABILITIES OF IFR CIGS ARE HIGH IN THE CSRA BY 08Z-10Z AND AT CAE/CUB AFTER 12Z BEFORE CIGS IMPROVE TO MVFR LATE MORNING INTO EARLY AFTERNOON AS SOUTHERLY FLOW DEVELOPS AHEAD OF THE APPROACHING COLD FRONT. CHANCES FOR SHOWERS WILL INCREASE DURING THE AFTERNOON BUT CONFIDENCE IS LOW IN TERMINALS BEING IMPACTED BY THE SHOWERS AT THIS TIME SO NOT INCLUDED IN THIS FORECAST. EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS POSSIBLE SUNDAY. RESTRICTIONS POSSIBLE AGAIN LATE SUNDAY NIGHT AND MONDAY WITH POSSIBLE WEDGE CONDITIONS DEVELOPING. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030. GA...NONE. && $$ 77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
625 AM EST THU DEC 4 2014 .SYNOPSIS... A WEAK COLD FRONT WILL MOVE THROUGH THE FORECAST AREA LATER THIS MORNING. HIGH PRESSURE WILL RIDGE INTO THE AREA FROM THE NORTH BEHIND THE FRONT LATER TODAY INTO FRIDAY. ANOTHER COLD FRONT WILL APPROACH SATURDAY AND MOVE THROUGH THE AREA SATURDAY NIGHT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THIS MORNING...A WEAK COLD FRONT CURRENTLY MOVING THROUGH CENTRAL NORTH CAROLINA WILL SINK SOUTH EARLY THIS MORNING AND PUSH THROUGH THE AREA BY LATE MORNING. GIVEN LATEST OBS ACROSS THE AREA EARLY THIS MORNING WITH VISIBILITIES AT OR BELOW ONE-QUARTER OF A MILE...HAVE DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE ENTIRE AREA UNTIL 9 AM THIS MORNING. TODAY...WEAK COLD FRONT WILL PUSH THROUGH THE AREA WITH HIGH PRESSURE BUILDING IN BEHIND THE FRONT. MOISTURE REMAINS SHALLOW WITH LITTLE IN THE WAY OF ISENTROPIC LIFT. DAYTIME HIGHS WILL RANGE FROM AROUND 60 NORTH TO THE UPPER 60S SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... HIGH PRESSURE WILL RIDGE INTO THE FORECAST AREA FROM THE NORTH TONIGHT THROUGH FRIDAY. THE MODELS CONTINUE TO SHOW LITTLE ISENTROPIC LIFT AND SHALLOW MOISTURE. HIGH PRESSURE WILL BUILD INTO THE AREA LATER TODAY INTO FRIDAY. THE GUIDANCE CONSENSUS SUPPORTS POPS LESS THAN 20 PERCENT THROUGH THE SHORT TERM. HIGH LOW-LEVEL MOISTURE AND DIURNAL COOLING SHOULD LEAD TO AREAS OF STRATUS AND FOG FRIDAY MORNING. LOWS TONIGHT WILL BE IN THE 40S. HIGHS FRIDAY WILL RANGE FROM THE UPPER 50S NORTH TO THE LOWER 60S SOUTH. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... NO CHANGES TO THE EXTENDED FORECAST. THE GFS AND ECMWF DISPLAY A FRONTAL SYSTEM APPROACHING THE FORECAST AREA FRIDAY NIGHT AND SATURDAY WITH THE SYSTEM MOVING THROUGH THE AREA SATURDAY NIGHT. THE MODELS HAVE NOT BEEN CONSISTENT WITH THE PLACEMENT OF LOW PRESSURE DEVELOPING ALONG THE FRONT AND THE EXTENT OF MOISTURE IN THE FORECAST AREA...BUT GENERALLY HAVE INDICATED THE DEEPEST MOISTURE DURING THE DAY SATURDAY. WE FORECASTED THE HIGHEST POPS SATURDAY AND GENERALLY USED A BLEND OF THE GFS...ECMWF...AND EKD MOS. THE RAIN CHANCE SHOULD DIMINISH SUNDAY...BUT CONFIDENCE IS NOT HIGH BECAUSE PREVIOUS MODEL RUNS AND THE LATEST ECMWF HAVE SHOWN CONTINUED HIGH WRAP-AROUND MOISTURE ASSOCIATED WITH AN OFFSHORE LOW. THE 12Z GFS WAS MORE PROGRESSIVE AND HAD DRY RIDGING DOMINATING SUNDAY. CONFIDENCE REMAINS LOW DURING THE REST OF THE MEDIUM-RANGE PERIOD. THE 12Z GFS HAD CONSIDERABLE MOISTURE AND ISENTROPIC LIFT MONDAY WITH A DRY PATTERN DURING THE REST OF THE PERIOD. THE 00Z WEDNESDAY ECMWF HAD A MID-LEVEL CUT-OFF LOW NEAR THE FORECAST AREA TUESDAY AND WEDNESDAY. THE GFS ENSEMBLE HAD A HIGH SPREAD DURING THE PERIOD. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... LIFR/IFR CONDITIONS EARLY THIS MORNING DUE TO WIDESPREAD FOG. WEAK SURFACE HIGH PRESSURE OVER THE CAROLINAS AND GEORGIA WILL GRADUALLY WEAKEN AS A WEAK SLOW MOVING FRONT BACK DOORS THROUGH THE AREA THIS MORNING. DESPITE HIGH CLOUDINESS...WIDESPREAD FOG ACROSS THE AREA THIS MORNING RESULTING IN LIFR/LIFR. EXCEPTION IS DNL WHERE CONDITIONS VFR AT THE MOMENT...BUT POSSIBLE FOG DEVELOPMENT AFTER 12Z. LATEST HRRR GUIDANCE SUGGEST VISIBILITY MAY IMPROVE AFTER 14Z BUT LINGERING MVFR CONDITIONS THROUGH 17Z AT MOST TERMINALS UNTIL WEAK FRONT MOVES THROUGH AND NORTHEAST WINDS DEVELOP. VFR THROUGH THE AFTERNOON AND EARLY EVENING WITH STRATO-CU AND HIGH CLOUDS. NORTHEAST OR EAST WINDS MAINLY LESS THAN 10 KTS. HIGH LOW-LEVEL MOISTURE TONIGHT AND DRY AIR ALOFT MAY RESULT IN FOG AND OR STRATUS DEVELOPMENT AGAIN...MVFR FORECAST BUT LIFR/IFR POSSIBLE. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE AT TIMES MAINLY AT NIGHT OR EARLY MORNING DUE TO FOG OR STRATUS THROUGH SATURDAY. SHOWER ACTIVITY POSSIBLE SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ015-016- 018-020>022-025>031-035>038-041. FLASH FLOOD WATCH THROUGH THIS EVENING FOR SCZ030. GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR GAZ040- 063>065-077. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL 1203 PM CST THU DEC 4 2014 .SHORT TERM... 211 AM CST THROUGH FRIDAY NIGHT... IR IMAGERY EARLY THIS MORNING SHOWS CONSIDERABLE MID/UPR LEVEL CLOUDS OVER THE REGION...ASSOCIATED WITH A WEAK MID-LVL VORT. THIS FEATURE IS RATHER WEAK...BUT SOME ASCENT WITHIN THE MOIST COLUMN IS PROBABLE AND COULD BE JUST ENOUGH TO PRODUCE SOME FLURRIES ACROSS SOUTHERN WISC/FAR NORTHERN IL JUST AFT DAYBREAK THRU NOON BEFORE ENDING. TEMPS AHEAD OF THIS FEATURE HAVE REMAINED IN THE LOW/MID 20S...THANKS IN PART TO THE THICK CLOUD COVER INHIBITING COOLING. THE NEAR SFC ENVIRONMENT REMAINS DRY...WITH DEW POINTS STILL IN THE LOW/MID TEENS. SO ANY PRECIP THAT CAN DEVELOP WOULD REMAIN VERY LIGHT AND CONFINED TO THE FAR NORTHERN PORTIONS OF THE FORECAST AREA. ANTI-CYCLONIC FLOW WILL STEADILY DEPART TO THE NORTHEAST...WITH LLVL FLOW TURNING EAST/SOUTHEAST ALONG THE BACK EDGE OF THE SFC RIDGE. LLVLS WILL REMAIN RATHER DRY...WITH DEW PTS LIKELY HOLDING IN THE UPR TEENS TO LOW 20S. THEN LATER THIS AFTN/EVE THE SOUTHERN STREAM SYSTEM WILL BEGIN TO ADVECT NORTH...AND BASED ON LATEST WV IMAGERY...LLVL MOISTURE SHUD START TO ADVECT INTO THE SOUTHERN PORTIONS OF THE FORECAST AREA. THIS WILL LIKELY KEEP CONSIDERABLE SOLAR SHIELDING IN PLACE...HOWEVER WITH THE 850MB THERMAL TROUGH SLOWLY DEPARTING TO THE NORTHEAST THIS AFTN...SFC TEMPS SHUD STILL PUSH INTO THE LOW/MID 30S. MID-LVL FLOW REMAIN FLAT TONIGHT...AS MUCH OF THE CONUS TRANSITIONS INTO A SEMI-ZONAL PATTERN. THIS WILL ALLOW THE SOUTHERN STREAM MOIST CONVEYOR TO ADVECT NORTH INTO THE MISSOURI VALLEY...WITH GUIDANCE INDICATING LGT QPF REACHING THE SOUTHERN CWFA JUST AFT MIDNIGHT. UNFORTUNATELY THERMAL PROFILES INDICATE A WARM WEDGE ABOVE THE SFC THAT WOULD ALLOW FULL MELT OF ANY DENDRITES...AND SUPPORT PRECIP FALLING AS LGT FZRA. DROPLET SIZE COULD BE SMALL...AND WITH THE LACK OF STRONG ASCENT OVERNIGHT...SO IT IS PLAUSIBLE THAT PRECIP COULD END UP BEING FREEZING DRIZZLE. THE FOCUS WILL BE SOUTH OF I-80 BEFORE DAYBREAK FRI. HI-RES LOCAL SOLUTION ALONG WITH THE NAM INDICATE A WEAK MID-LVL WAVE RIDING NORTHEAST FROM THE CENTRAL PLAINS FRI MORNING...WHICH COULD PUSH THE PRECIP SHIELD FURTHER NORTH JUST AFT DAYBREAK. AS A RESULT OF THIS HAVE INCLUDED A MENTION OF PATCHY FREEZING DRIZZLE ACROSS THE NORTHERN PORTIONS OF THE CWFA FRI MORNING. THEN AS THE MORNING PROGRESSES TEMPS SHUD WARM AT THE SFC TO CHANGE ALL PRECIP OVER TO LIQUID FORM...BUT AGAIN REMAIN FOCUSED ALONG AND SOUTH OF I-80. THE MID-LVL WAVE WILL QUICKLY PIVOT EAST...WITH ANTI-CYCLONIC FLOW DROPPING SOUTHEAST FROM CENTRAL CANADA INTO THE UPPER MIDWEST FRI AFTN. THIS WILL HELP TO KICK THE BETTER MOISTURE SHIELD EAST FRI NGT...AND SLOWLY BRING DRY AIR BACK INTO THE NORTHWEST CWFA FRI EVE. TEMPS FRI WILL EVENTUALLY PUSH INTO THE UPR 30S/ARND 40 FOR THE NORTH CWFA...AND POSSIBLY TOUCH THE LOW 40S IN THE FAR SOUTHERN CWFA FRI AFTN. BEACHLER && .LONG TERM... 211 AM CST SATURDAY THROUGH MIDDLE NEXT WEEK... FOR THE FIRST HALF OF THE WEEKEND ENSEMBLES ARE DEMONSTRATING MINIMAL SPREAD WITH RESPECT TO THE 500MB HEIGHTS...SUGGESTING RIDGING WILL BE IN PLACE ACROSS THE ROCKIES WITH WEAK TROUGHING DEPARTING TO THE NORTHEAST ACROSS ONTARIO/QUEBEC. WITH SOME AMPLIFICATION TO THE UPSTREAM RIDGE OVER THE ROCKIES...A WEAK TROUGH IS PROGGED TO DEVELOP AND SLIDE SOUTHEAST ACROSS THE GREAT LAKES EARLY NEXT WEEK...BUT THEN THE RIDGE STARTS TO FLATTEN AND KICKS THE TROUGH EAST WITH A SEMI- ZONAL PATTERN CLOSER TO THE MIDDLE OF NEXT WEEK. THE WEEKEND CURRENTLY LOOKS TO REMAIN DRY...HOWEVER WITH THE ARRIVAL OF THE AFOREMENTIONED TROUGH AT THE START OF NEXT WEEK...LGT PRECIP IS POSSIBLE MON/MON NGT. THEN SFC RIDGING IS POISED TO RETURN FOR TUE/WED WITH DRY WEATHER. TEMPS FOR THE WEEKEND INTO EARLY NEXT WEEK LOOK TO REMAIN RATHER UNIFORM...OR GENERALLY IN THE UPR 30S/ARND 40. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WINDS 10 KT OR LESS SHIFTING FROM ENE TO SE LATE MORNING/EARLY AFTERNOON CONTINUING THROUGH FRIDAY MORNING. * CIGS LOWERING TO MVFR TONIGHT AND A MIX OF IFR AND LOW END MVFR BY FRIDAY MORNING. * LIGHT RAIN POSSIBLE BY FRIDAY AFTERNOON. MB/DJO //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS MOVING OFF TO THE ENE OF THE CHICAGO CWA CAUSING LIGHT WINDS TO VEER AROUND TOWARD SOUTHEASTERLY LATE THIS MORNING. WIND SPEEDS THROUGHOUT THE PERIOD ARE EXPECTED TO BE 10 KTS OR LESS...WITH THE HIGHEST WIND SPEEDS REACHING 8-10 KTS IN THE AFTERNOON HOURS. GRADUALLY LOWERING CEILINGS ARE EXPECTED THROUGH THE DAY...REACHING MVFR CATEGORY IN THE EARLY MORNING HOURS FRIDAY. AS THE LOWER CEILINGS ARRIVE...A BRIEF PERIOD OF -FZDZ REMAINS POSSIBLE IN THE AREA...HOWEVER THE PROBABILITY OF PRECIPITATION LOOKS TOO LOW AT THIS TIME FOR MENTION IN THE CHICAGO AREA TAFS. BY LATE MORNING THROUGH AFTERNOON...CEILINGS SHOULD GENERALLY REACH IFR CATEGORY WITH LIGHT FOG. A BETTER CHANCE FOR RAIN WILL ALSO ARRIVE AS THICKER CLOUD COVER ALOFT ARRIVES IN THE AREA. MB/DJO //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM-HIGH CONFIDENCE IN WIND DETAILS. * HIGH CONFIDENCE IN CIGS LOWERING TO MVFR/IFR TONIGHT/TOMORROW. * MEDIUM CONFIDENCE IN -RA OCCURRING FRIDAY AFTERNOON. MB/DJO //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...SLIGHT CHANCE OF RAIN. MVFR/IFR POSSIBLE. NE WINDS BECOMING N. SATURDAY...MVFR CIGS PSBL EARLY...OTHERWISE VFR. N WINDS BECOMING NE. SUNDAY...MAINLY VFR. CHANCE OF LGT SLEET/SNOW AND MVFR SUNDAY NIGHT. E WINDS BECOMING SE. MONDAY...CHANCE OF RAIN OR SNOW. MVFR/BRIEF IFR POSSIBLE. SSW WINDS BECOMING NW. TUESDAY...MAINLY VFR. N WINDS BECOMING NE. WEDNESDAY...VFR. S WINDS. MDB && .MARINE... 247 AM CST HIGH PRESSURE WILL CROSS LAKE MICHIGAN TODAY ALLOWING THE GUSTY WEST TO NORTHWEST WINDS ACROSS NORTHERN SECTIONS OF THE LAKE TO DIMINISH AND BECOME SOUTHERLY. WINDS FURTHER SOUTH WILL TAKE ON A MORE EASTERLY DIRECTION BEFORE BECOMING SOUTHEAST THIS AFTERNOON...WITH A MORE UNIFORM SOUTH TO SOUTHEAST DIRECTION ACROSS THE LAKE INTO TONIGHT. LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS FRIDAY MORNING AND TRACK ACROSS THE OHIO VALLEY FRIDAY NIGHT. AS THIS OCCURS...STRONG HIGH PRESSURE WILL MOVE INTO THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY AND ACROSS THE UPPER LAKES SATURDAY AND SATURDAY NIGHT. WINDS WILL TURN MORE VARIABLE LATER FRIDAY AS A WEAKNESS IN THE GRADIENT DEVELOPS BETWEEN THE LOW AND THE HIGH BUT A BRISK NORTH WIND WILL DEVELOP AS THE GRADIENT BECOMES ESTABLISHED FRIDAY NIGHT. WINDS WILL TURN NORTHEASTERLY SATURDAY MORNING AND DIMINISH INTO SATURDAY EVENING AS THE HIGH MOVES ACROSS. WINDS WILL WORK AROUND TO THE EAST THEN SOUTHEAST LATER SUNDAY AS LOW PRESSURE TRACKS ALONG THE U.S./CANADIAN BORDER. HAVE SEEN SOME VARIATION ON THE TRACK OF THIS LOW BUT THERE IS BETTER AGREEMENT ON IT TRACKING NORTH OF THE LAKE MONDAY. SOUTHEAST WINDS WILL INCREASE AHEAD OF THE LOW SUNDAY NIGHT THEN TURN SOUTHWESTERLY THEN NORTHWESTERLY AS A COOL FRONT PASSES LATER MONDAY. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE LAKE TUESDAY WITH THE TRACK OF SUBSEQUENT LOW PRESSURE LIKELY SETTING UP ACROSS SOUTHERN CANADA. THIS WILL KEEP A PREDOMINANTLY SOUTHERLY FLOW ACROSS THE LAKE THROUGH THE REST OF NEXT WEEK. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1133 AM CST Thu Dec 4 2014 .UPDATE... ISSUED AT 953 AM CST THU DEC 4 2014 Area of precipitation continues to push across locations east of I-55 late this morning. Surface reports as of 945 am mainly showing the areas south of I-70 as rain. Mixture occurring just north of here, with mainly snow and some snow/ice pellets as far north as a Lincoln to Danville line. Temperatures in that area creeping upward and this should become more rain with time before diminishing early afternoon. Latest RAP suggests perhaps a bit of drizzle reforming across the southwest CWA early in the afternoon as well. Have sent some updated zones to reflect the precip types this morning and adjust some of the PoP`s into tonight as well. Some minor adjustments also needed for the temperature trends. && .SHORT TERM...(Today through Saturday) ISSUED AT 330 AM CST THU DEC 4 2014 1031 mb Canadian high pressure over WI and northern IL has been providing dry weather so far over central/SE IL though blanket of mid/high clouds now covers much of the region. Temps range from mid 20s far NE counties to the lower 30s from Jacksonville to Robinson SW. Weak short wave affecting IL today and will develop light precipitation over mainly southern half of CWA today. Radar mosaic shows several echos over central and southern IL but most of these are currently virga and precipitation not reaching the ground due to very dry atmosphere per 00Z ILX/DVN soundings. Have chances of light freezing rain and sleet developing from I-72 south during this morning and changing to lift rain later this morning and afternoon. Areas north of Lincoln generally dry today though fairly cloudy there as well. Highs today in mid to upper 30s with Lawrenceville near 40F. Have lingering chances of light rain over eastern/SE IL this evening and then rain chances to increase from the south overnight as storm system in the SW U.S. approaches the central/southern plains. Light freezing rain possible north of Lincoln overnight but precip here is very light perhaps from a trace to a few hundredths. Have best chances of rain developing during Friday and Fri night especially in southeast IL where moderate rainfall expected. Rain to diminish from NW to SE during overnight Fri night and Sat morning with totals of 1-1.5 inches in southeast IL while near a tenth inch north of Peoria over Knox, Stark and Marshall counties. && .LONG TERM...(Saturday night through Thursday) ISSUED AT 330 AM CST THU DEC 4 2014 Strong Canadian high pressure to settle into southeast Canada Sunday and ridge SW into IL providing dry and seasonably cool conditions. Ridge drifts east of IL Sunday evening while a northern stream short wave/upper level low translates across the northern plains into the upper Great Lakes by Monday morning. This to bring isolated chances of light rain/snow showers later Sunday night and Monday, then shifting east into IN by overnight Monday night and Tue. Surface ridge to drift east over IL Tue night and Wed returning dry weather. Highs in the upper 30s and lower 40s expected Mon-Wed. Temperatures then expected to moderate by next Thu and Fri as upper level ridge builds into IL. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) ISSUED AT 1133 AM CST THU DEC 4 2014 Band of snow showers that reduced visibility at KCMI recently has lifted northeast, and much of the precipitation this afternoon should not affect the TAF sites. However, some MVFR and IFR ceilings loom across southern Illinois and are lifting north, and should be spreading into central Illinois toward mid afternoon. General trend will be for widespread ceilings below 1000 feet by mid evening, and the TAFs will have these persisting the remainder of the forecast period. Visibility should lower some as some light drizzle and fog begins to develop, with more steady light rain spreading into the area after 12Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...07 LONG TERM...07 AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1014 AM CST THU DEC 4 2014 .SHORT TERM... 211 AM CST THROUGH FRIDAY NIGHT... IR IMAGERY EARLY THIS MORNING SHOWS CONSIDERABLE MID/UPR LEVEL CLOUDS OVER THE REGION...ASSOCIATED WITH A WEAK MID-LVL VORT. THIS FEATURE IS RATHER WEAK...BUT SOME ASCENT WITHIN THE MOIST COLUMN IS PROBABLE AND COULD BE JUST ENOUGH TO PRODUCE SOME FLURRIES ACROSS SOUTHERN WISC/FAR NORTHERN IL JUST AFT DAYBREAK THRU NOON BEFORE ENDING. TEMPS AHEAD OF THIS FEATURE HAVE REMAINED IN THE LOW/MID 20S...THANKS IN PART TO THE THICK CLOUD COVER INHIBITING COOLING. THE NEAR SFC ENVIRONMENT REMAINS DRY...WITH DEW POINTS STILL IN THE LOW/MID TEENS. SO ANY PRECIP THAT CAN DEVELOP WOULD REMAIN VERY LIGHT AND CONFINED TO THE FAR NORTHERN PORTIONS OF THE FORECAST AREA. ANTI-CYCLONIC FLOW WILL STEADILY DEPART TO THE NORTHEAST...WITH LLVL FLOW TURNING EAST/SOUTHEAST ALONG THE BACK EDGE OF THE SFC RIDGE. LLVLS WILL REMAIN RATHER DRY...WITH DEW PTS LIKELY HOLDING IN THE UPR TEENS TO LOW 20S. THEN LATER THIS AFTN/EVE THE SOUTHERN STREAM SYSTEM WILL BEGIN TO ADVECT NORTH...AND BASED ON LATEST WV IMAGERY...LLVL MOISTURE SHUD START TO ADVECT INTO THE SOUTHERN PORTIONS OF THE FORECAST AREA. THIS WILL LIKELY KEEP CONSIDERABLE SOLAR SHIELDING IN PLACE...HOWEVER WITH THE 850MB THERMAL TROUGH SLOWLY DEPARTING TO THE NORTHEAST THIS AFTN...SFC TEMPS SHUD STILL PUSH INTO THE LOW/MID 30S. MID-LVL FLOW REMAIN FLAT TONIGHT...AS MUCH OF THE CONUS TRANSITIONS INTO A SEMI-ZONAL PATTERN. THIS WILL ALLOW THE SOUTHERN STREAM MOIST CONVEYOR TO ADVECT NORTH INTO THE MISSOURI VALLEY...WITH GUIDANCE INDICATING LGT QPF REACHING THE SOUTHERN CWFA JUST AFT MIDNIGHT. UNFORTUNATELY THERMAL PROFILES INDICATE A WARM WEDGE ABOVE THE SFC THAT WOULD ALLOW FULL MELT OF ANY DENDRITES...AND SUPPORT PRECIP FALLING AS LGT FZRA. DROPLET SIZE COULD BE SMALL...AND WITH THE LACK OF STRONG ASCENT OVERNIGHT...SO IT IS PLAUSIBLE THAT PRECIP COULD END UP BEING FREEZING DRIZZLE. THE FOCUS WILL BE SOUTH OF I-80 BEFORE DAYBREAK FRI. HI-RES LOCAL SOLUTION ALONG WITH THE NAM INDICATE A WEAK MID-LVL WAVE RIDING NORTHEAST FROM THE CENTRAL PLAINS FRI MORNING...WHICH COULD PUSH THE PRECIP SHIELD FURTHER NORTH JUST AFT DAYBREAK. AS A RESULT OF THIS HAVE INCLUDED A MENTION OF PATCHY FREEZING DRIZZLE ACROSS THE NORTHERN PORTIONS OF THE CWFA FRI MORNING. THEN AS THE MORNING PROGRESSES TEMPS SHUD WARM AT THE SFC TO CHANGE ALL PRECIP OVER TO LIQUID FORM...BUT AGAIN REMAIN FOCUSED ALONG AND SOUTH OF I-80. THE MID-LVL WAVE WILL QUICKLY PIVOT EAST...WITH ANTI-CYCLONIC FLOW DROPPING SOUTHEAST FROM CENTRAL CANADA INTO THE UPPER MIDWEST FRI AFTN. THIS WILL HELP TO KICK THE BETTER MOISTURE SHIELD EAST FRI NGT...AND SLOWLY BRING DRY AIR BACK INTO THE NORTHWEST CWFA FRI EVE. TEMPS FRI WILL EVENTUALLY PUSH INTO THE UPR 30S/ARND 40 FOR THE NORTH CWFA...AND POSSIBLY TOUCH THE LOW 40S IN THE FAR SOUTHERN CWFA FRI AFTN. BEACHLER && .LONG TERM... 211 AM CST SATURDAY THROUGH MIDDLE NEXT WEEK... FOR THE FIRST HALF OF THE WEEKEND ENSEMBLES ARE DEMONSTRATING MINIMAL SPREAD WITH RESPECT TO THE 500MB HEIGHTS...SUGGESTING RIDGING WILL BE IN PLACE ACROSS THE ROCKIES WITH WEAK TROUGHING DEPARTING TO THE NORTHEAST ACROSS ONTARIO/QUEBEC. WITH SOME AMPLIFICATION TO THE UPSTREAM RIDGE OVER THE ROCKIES...A WEAK TROUGH IS PROGGED TO DEVELOP AND SLIDE SOUTHEAST ACROSS THE GREAT LAKES EARLY NEXT WEEK...BUT THEN THE RIDGE STARTS TO FLATTEN AND KICKS THE TROUGH EAST WITH A SEMI- ZONAL PATTERN CLOSER TO THE MIDDLE OF NEXT WEEK. THE WEEKEND CURRENTLY LOOKS TO REMAIN DRY...HOWEVER WITH THE ARRIVAL OF THE AFOREMENTIONED TROUGH AT THE START OF NEXT WEEK...LGT PRECIP IS POSSIBLE MON/MON NGT. THEN SFC RIDGING IS POISED TO RETURN FOR TUE/WED WITH DRY WEATHER. TEMPS FOR THE WEEKEND INTO EARLY NEXT WEEK LOOK TO REMAIN RATHER UNIFORM...OR GENERALLY IN THE UPR 30S/ARND 40. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * WINDS 10 KT OR LESS SHIFTING FROM ENE TO SE LATE MORNING/EARLY AFTERNOON CONTINUING THROUGH FRIDAY MORNING. * CIGS LOWERING TO MVFR TONIGHT AND LOW END MVFR BY FRIDAY MORNING. * CHANCE FOR A PERIOD OF -FZDZ EARLY FRIDAY MORNING. MB/DJO //DISCUSSION...UPDATED 12Z... HIGH PRESSURE IS PASSING OVER THE TERMINALS THIS MORNING. WINDS ARE STARTING TO SHOW A STEADIER NORTHEAST DIRECTION AND WILL CONTINUE TO SWING AROUND TO EAST-SOUTHEAST THROUGH LATE MORNING. EXPECT SPEEDS OF 10 KT OR LESS...THOUGH A FEW 11-12 KT SPEEDS COULD OCCUR FOR A TIME THIS AFTERNOON BUT LOOK TO BE INFREQUENT IF THEY DO OCCUR. A PASSING UPPER TROUGH WILL KEEP MID LEVEL CLOUD COVER IN PLACE WITH SOME LOWERING OF BASES THROUGH THE MORNING. OTHERWISE CEILINGS WILL LOWER TONIGHT...LIKELY REACHING MVFR DURING THE EARLY OVERNIGHT...AS LOW PRESSURE MOVES TOWARD THE OHIO VALLEY. CIGS MAY LOWER NEAR IFR LEVELS FRIDAY MORNING. THE LOW CLOUDS WILL ALSO BRING A CHANCE FOR SOME -FZDZ FRIDAY MORNING WITH TEMPERATURES WARMING ABOVE FREEZING INTO LATE MORNING. PRECIPITATION THIS FAR NORTH SHOULD BE VERY LIGHT IF IT DOES OCCUR. MDB //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MEDIUM-HIGH CONFIDENCE IN WIND DETAILS. * HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TONIGHT. * MEDIUM CONFIDENCE IN -FZDZ OCCURRING FRIDAY MORNING. MB/DJO //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...SLIGHT CHANCE OF RAIN. MVFR/IFR POSSIBLE. NE WINDS BECOMING N. SATURDAY...MVFR CIGS PSBL EARLY...OTHERWISE VFR. N WINDS BECOMING NE. SUNDAY...MAINLY VFR. CHANCE OF LGT SLEET/SNOW AND MVFR SUNDAY NIGHT. E WINDS BECOMING SE. MONDAY...CHANCE OF RAIN OR SNOW. MVFR/BRIEF IFR POSSIBLE. SSW WINDS BECOMING NW. TUESDAY...MAINLY VFR. N WINDS BECOMING NE. WEDNESDAY...VFR. S WINDS. MDB && .MARINE... 247 AM CST HIGH PRESSURE WILL CROSS LAKE MICHIGAN TODAY ALLOWING THE GUSTY WEST TO NORTHWEST WINDS ACROSS NORTHERN SECTIONS OF THE LAKE TO DIMINISH AND BECOME SOUTHERLY. WINDS FURTHER SOUTH WILL TAKE ON A MORE EASTERLY DIRECTION BEFORE BECOMING SOUTHEAST THIS AFTERNOON...WITH A MORE UNIFORM SOUTH TO SOUTHEAST DIRECTION ACROSS THE LAKE INTO TONIGHT. LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS FRIDAY MORNING AND TRACK ACROSS THE OHIO VALLEY FRIDAY NIGHT. AS THIS OCCURS...STRONG HIGH PRESSURE WILL MOVE INTO THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY AND ACROSS THE UPPER LAKES SATURDAY AND SATURDAY NIGHT. WINDS WILL TURN MORE VARIABLE LATER FRIDAY AS A WEAKNESS IN THE GRADIENT DEVELOPS BETWEEN THE LOW AND THE HIGH BUT A BRISK NORTH WIND WILL DEVELOP AS THE GRADIENT BECOMES ESTABLISHED FRIDAY NIGHT. WINDS WILL TURN NORTHEASTERLY SATURDAY MORNING AND DIMINISH INTO SATURDAY EVENING AS THE HIGH MOVES ACROSS. WINDS WILL WORK AROUND TO THE EAST THEN SOUTHEAST LATER SUNDAY AS LOW PRESSURE TRACKS ALONG THE U.S./CANADIAN BORDER. HAVE SEEN SOME VARIATION ON THE TRACK OF THIS LOW BUT THERE IS BETTER AGREEMENT ON IT TRACKING NORTH OF THE LAKE MONDAY. SOUTHEAST WINDS WILL INCREASE AHEAD OF THE LOW SUNDAY NIGHT THEN TURN SOUTHWESTERLY THEN NORTHWESTERLY AS A COOL FRONT PASSES LATER MONDAY. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE LAKE TUESDAY WITH THE TRACK OF SUBSEQUENT LOW PRESSURE LIKELY SETTING UP ACROSS SOUTHERN CANADA. THIS WILL KEEP A PREDOMINANTLY SOUTHERLY FLOW ACROSS THE LAKE THROUGH THE REST OF NEXT WEEK. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 953 AM CST Thu Dec 4 2014 .UPDATE... ISSUED AT 953 AM CST THU DEC 4 2014 Area of precipitation continues to push across locations east of I-55 late this morning. Surface reports as of 945 am mainly showing the areas south of I-70 as rain. Mixture occurring just north of here, with mainly snow and some snow/ice pellets as far north as a Lincoln to Danville line. Temperatures in that area creeping upward and this should become more rain with time before diminishing early afternoon. Latest RAP suggests perhaps a bit of drizzle reforming across the southwest CWA early in the afternoon as well. Have sent some updated zones to reflect the precip types this morning and adjust some of the PoP`s into tonight as well. Some minor adjustments also needed for the temperature trends. && .SHORT TERM...(Today through Saturday) ISSUED AT 330 AM CST THU DEC 4 2014 1031 mb Canadian high pressure over WI and northern IL has been providing dry weather so far over central/se IL though blanket of mid/high clouds now covers much of the region. Temps range from mid 20s far ne counties to the lower 30s from Jacksonville to Robinson sw. Weak short wave affecting IL today and will develop light precipitation over mainly southern half of CWA today. Radar mosaic shows several echos over central and southern IL but most of these are currently virga and precipitation not reaching the ground due to very dry atmosphere per 00Z ILX/DVN soundings. Have chances of light freezing rain and sleet developing from I-72 south during this morning and changing to lift rain later this morning and afternoon. Areas north of Lincoln generally dry today though fairly cloudy there as well. Highs today in mid to upper 30s with Lawrenceville near 40F. Have lingering chances of light rain over eastern/se IL this evening and then rain chances to increase from the south overnight as storm system in the sw U.S. approaches the central/southern plains. Light freezing rain possible north of Lincoln overnight but precip here is very light perhaps from a trace to a few hundredths. Have best chances of rain developing during Friday and Fri night especially in southeast IL where moderate rainfall expected. Rain to diminish from nw to se during overnight Fri night and Sat morning with totals of 1-1.5 inches in southeast IL while near a tenth inch north of Peoria over Knox, Stark and Marshall counties. && .LONG TERM...(Saturday night through Thursday) ISSUED AT 330 AM CST THU DEC 4 2014 Strong Canadian high pressure to settle into southeast Canada Sunday and ridge sw into IL providing dry and seasonably cool conditions. Ridge drifts east of IL Sunday evening while a northern stream short wave/upper level low translates across the northern plains into the upper Great Lakes by Monday morning. This to bring isolated chances of light rain/snow showers later Sunday night and Monday, then shifting east into IN by overnight Monday night and Tue. Surface ridge to drift east over IL Tue night and Wed returning dry weather. Highs in the upper 30s and lower 40s expected Mon-Wed. Temperatures then expected to moderate by next Thu and Fri as upper level ridge builds into IL. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) ISSUED AT 558 AM CST THU DEC 4 2014 VFR conditions will begin at all sites this morning. Conditions will decrease to MVFR around noon at SPI/DEC/CMI and then in the late afternoon at PIA and BMI. Returns on radar are probably just mid clouds or Virga since the lower levels are very dry, temp/dewpoint spreads are around 10F at some places, and surface reports of pcpn have been hard to come by. However, by later this morning as the lower levels moisten up slowly, there could be some light pcpn occurring at SPI/DEC/CMI so will have a VCSH at those three sites. PIA and BMI will remain dry this morning and into this afternoon. SPI/DEC/CMI will see a break in the pcpn this afternoon, but MVFR cigs are expected. By around 03z this evening vis and cigs will decrease, but remain in the MVFR range. With the lower vis, drizzle will be possible too. Conditions will fall into the IFR category around midnight at SPI/DEC/CMI with cigs below 1kft and vis around 2sm. Drizzle will also continue into the overnight hours. Temps should be warm enough at this sites that any pcpn overnight will be liquid. PIA and BMI will also see conditions decrease into IFR, but after midnight. Pcpn should stay south of these two sites, but a slight chance is still there for freezing rain/drizzle, given temps below freezing tonight. However, for now will not add in TAFs, but would not be surprised to see it added later today. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...07 LONG TERM...07 AVIATION...Auten
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1030 PM EST FRI DEC 5 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 953 PM EST FRI DEC 5 2014 FORECAST IS IN GOOD SHAPE AND MADE NO MAJOR CHANGES. RAIN WILL CONTINUE ACROSS THE AREA AS LOW PRESSURE MOVES SOUTH OF CENTRAL INDIANA AND AN UPPER TROUGH MOVES INTO THE AREA. LATER TONIGHT AS FORCING SHIFTS EAST...RAIN WILL DIMINISH SOME FROM NORTHWEST TO SOUTHEAST. WARM AIR WILL REMAIN JUST SOUTH OF THE AREA. PREVIOUS DISCUSSION FOLLOWS... RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 ENSEMBLES INDICATE A FAIRLY STRONG UPPER TROUGH THAT IS EXPECTED TO DROP SOUTHEAST ACROSS THE GREAT LAKES MONDAY NIGHT INTO TUESDAY. A FEW OF THE ENSEMBLES SUGGEST THERE MAY A SOME LIGHT RAIN OR SNOW SHOWERS DURING THIS PERIOD AS THE TROUGH BRUSHES BY...BUT NOT ENOUGH OF A SIGNAL TO PUT IN THE FORECAST AT THIS TIME. WILL MONITOR THE TRENDS. OTHERWISE...SOME OF THE ENSEMBLES CUTOFF THE SOUTHERN PART OF THE EARLY WEEK TROUGH OVER THE EASTERN PARTS OF THE COUNTRY LATER NEXT WEEK...WHILE OTHERS ARE MORE PROGRESSIVE. DOESN/T APPEAR EITHER SOLUTION WILL RESULT IN MUCH OF A PRECIPITATION THREAT OVER THE AREA...BUT IF THE LESS PROGRESSIVE SOLUTIONS END UP BEING CORRECT...THE WARMUP LATE NEXT WEEK MAY BE TEMPERED SOME. && .AVIATION /DISCUSSION FOR THE 060600Z TAF ISSUANCE/... ISSUED AT 1030 PM EST FRI DEC 5 2014 IFR AND WORSE CONDITIONS EXPECTED TO BE THE MOST PREVALENT FLIGHT CATEGORIES THROUGH THE NIGHT. RADAR TRENDS AND 02Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT WITH MOSTLY A LIGHT INTENSITY BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. SHOULD SEE CONDITIONS IMPROVE TO MVFR AFTER 12Z FROM NORTHWEST TO SOUTHEAST. DO NOT EXPECT MUCH CLEARING OVERNIGHT SATURDAY NIGHT...BUT COULD SEE A FEW BREAKS. WINDS WILL BE BRIEFLY EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. SPEED AND DIRECTION SHOULD BE SIMILAR DURING THE DAY AND BECOME NORTHEAST 10 KNOTS OR LESS AFTER 00Z TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN/50 SHORT TERM...RYAN LONG TERM....JAS AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
953 PM EST FRI DEC 5 2014 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 953 PM EST FRI DEC 5 2014 FORECAST IS IN GOOD SHAPE AND MADE NO MAJOR CHANGES. RAIN WILL CONTINUE ACROSS THE AREA AS LOW PRESSURE MOVES SOUTH OF CENTRAL INDIANA AND AN UPPER TROUGH MOVES INTO THE AREA. LATER TONIGHT AS FORCING SHIFTS EAST...RAIN WILL DIMINISH SOME FROM NORTHWEST TO SOUTHEAST. WARM AIR WILL REMAIN JUST SOUTH OF THE AREA. PREVIOUS DISCUSSION FOLLOWS... RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 ENSEMBLES INDICATE A FAIRLY STRONG UPPER TROUGH THAT IS EXPECTED TO DROP SOUTHEAST ACROSS THE GREAT LAKES MONDAY NIGHT INTO TUESDAY. A FEW OF THE ENSEMBLES SUGGEST THERE MAY A SOME LIGHT RAIN OR SNOW SHOWERS DURING THIS PERIOD AS THE TROUGH BRUSHES BY...BUT NOT ENOUGH OF A SIGNAL TO PUT IN THE FORECAST AT THIS TIME. WILL MONITOR THE TRENDS. OTHERWISE...SOME OF THE ENSEMBLES CUTOFF THE SOUTHERN PART OF THE EARLY WEEK TROUGH OVER THE EASTERN PARTS OF THE COUNTRY LATER NEXT WEEK...WHILE OTHERS ARE MORE PROGRESSIVE. DOESN/T APPEAR EITHER SOLUTION WILL RESULT IN MUCH OF A PRECIPITATION THREAT OVER THE AREA...BUT IF THE LESS PROGRESSIVE SOLUTIONS END UP BEING CORRECT...THE WARMUP LATE NEXT WEEK MAY BE TEMPERED SOME. && .AVIATION /DISCUSSION FOR THE 060300Z IND TAF UPDATE/... ISSUED AT 920 PM EST FRI DEC 5 2014 WENT WITH MVFR AND TEMPO IFR CONDITIONS IN MODERATE RAIN THROUGH 04Z BASED ON TRENDS. OTHERWISE...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... IFR AND WORSE CONDITIONS EXPECTED THROUGH THE NIGHT. RADAR TRENDS AND 21Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. THE RAIN COULD BE MODERATE TO HEAVY AT TIMES THROUGH THE EVENING AS LOW LEVEL JET MIGRATES EASTWARD ACROSS KENTUCKY. HOWEVER...LAF LOOKS TO BE APT TO EXPERIENCE A MORE CONSTANT LIGHT RAIN. CEILINGS AND VISIBILITIES ARE EXPECTED TO BE IFR OR WORSE THROUGH THE NIGHT WITH LIFR THE MOST LIKELY CATEGORY FOR THE MAJORITY OF THE NIGHT. THEN...SHOULD SEE CONDITIONS IMPROVE TO IFR AND MVFR AFTER 12Z...EXCEPT A LITTLE EARLIER AT LAF. WINDS WILL START OFF EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN/50 SHORT TERM...RYAN LONG TERM....JAS AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
920 PM EST FRI DEC 5 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /TONIGHT/... ISSUED AT 347 PM EST FRI DEC 5 2014 RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 ENSEMBLES INDICATE A FAIRLY STRONG UPPER TROUGH THAT IS EXPECTED TO DROP SOUTHEAST ACROSS THE GREAT LAKES MONDAY NIGHT INTO TUESDAY. A FEW OF THE ENSEMBLES SUGGEST THERE MAY A SOME LIGHT RAIN OR SNOW SHOWERS DURING THIS PERIOD AS THE TROUGH BRUSHES BY...BUT NOT ENOUGH OF A SIGNAL TO PUT IN THE FORECAST AT THIS TIME. WILL MONITOR THE TRENDS. OTHERWISE...SOME OF THE ENSEMBLES CUTOFF THE SOUTHERN PART OF THE EARLY WEEK TROUGH OVER THE EASTERN PARTS OF THE COUNTRY LATER NEXT WEEK...WHILE OTHERS ARE MORE PROGRESSIVE. DOESN/T APPEAR EITHER SOLUTION WILL RESULT IN MUCH OF A PRECIPITATION THREAT OVER THE AREA...BUT IF THE LESS PROGRESSIVE SOLUTIONS END UP BEING CORRECT...THE WARMUP LATE NEXT WEEK MAY BE TEMPERED SOME. && .AVIATION /DISCUSSION FOR THE 060300Z IND TAF UPDATE/... ISSUED AT 920 PM EST FRI DEC 5 2014 WENT WITH MVFR AND TEMPO IFR CONDITIONS IN MODERATE RAIN THROUGH 04Z BASED ON TRENDS. OTHERWISE...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... IFR AND WORSE CONDITIONS EXPECTED THROUGH THE NIGHT. RADAR TRENDS AND 21Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. THE RAIN COULD BE MODERATE TO HEAVY AT TIMES THROUGH THE EVENING AS LOW LEVEL JET MIGRATES EASTWARD ACROSS KENTUCKY. HOWEVER...LAF LOOKS TO BE APT TO EXPERIENCE A MORE CONSTANT LIGHT RAIN. CEILINGS AND VISIBILITIES ARE EXPECTED TO BE IFR OR WORSE THROUGH THE NIGHT WITH LIFR THE MOST LIKELY CATEGORY FOR THE MAJORITY OF THE NIGHT. THEN...SHOULD SEE CONDITIONS IMPROVE TO IFR AND MVFR AFTER 12Z...EXCEPT A LITTLE EARLIER AT LAF. WINDS WILL START OFF EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
607 PM EST FRI DEC 5 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /TONIGHT/... ISSUED AT 347 PM EST FRI DEC 5 2014 RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 ENSEMBLES INDICATE A FAIRLY STRONG UPPER TROUGH THAT IS EXPECTED TO DROP SOUTHEAST ACROSS THE GREAT LAKES MONDAY NIGHT INTO TUESDAY. A FEW OF THE ENSEMBLES SUGGEST THERE MAY A SOME LIGHT RAIN OR SNOW SHOWERS DURING THIS PERIOD AS THE TROUGH BRUSHES BY...BUT NOT ENOUGH OF A SIGNAL TO PUT IN THE FORECAST AT THIS TIME. WILL MONITOR THE TRENDS. OTHERWISE...SOME OF THE ENSEMBLES CUTOFF THE SOUTHERN PART OF THE EARLY WEEK TROUGH OVER THE EASTERN PARTS OF THE COUNTRY LATER NEXT WEEK...WHILE OTHERS ARE MORE PROGRESSIVE. DOESN/T APPEAR EITHER SOLUTION WILL RESULT IN MUCH OF A PRECIPITATION THREAT OVER THE AREA...BUT IF THE LESS PROGRESSIVE SOLUTIONS END UP BEING CORRECT...THE WARMUP LATE NEXT WEEK MAY BE TEMPERED SOME. && .AVIATION /DISCUSSION FOR THE 060000Z TAF ISSUANCE/... ISSUED AT 607 PM EST FRI DEC 5 2014 IFR AND WORSE CONDITIONS EXPECTED THROUGH THE NIGHT. RADAR TRENDS AND 21Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. THE RAIN COULD BE MODERATE TO HEAVY AT TIMES THROUGH THE EVENING AS LOW LEVEL JET MIGRATES EASTWARD ACROSS KENTUCKY. HOWEVER...LAF LOOKS TO BE APT TO EXPERIENCE A MORE CONSTANT LIGHT RAIN. CEILINGS AND VISIBILITIES ARE EXPECTED TO BE IFR OR WORSE THROUGH THE NIGHT WITH LIFR THE MOST LIKELY CATEGORY FOR THE MAJORITY OF THE NIGHT. THEN...SHOULD SEE CONDITIONS IMPROVE TO IFR AND MVFR AFTER 12Z...EXCEPT A LITTLE EARLIER AT LAF. WINDS WILL START OFF EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....JAS AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1146 AM EST THU DEC 4 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 950 AM EST THU DEC 4 2014 AN UPPER WAVE AND MOISTENING SOUTHWEST UPGLIDE WILL BRING MIXED PRECIPITATION TO CENTRAL INDIANA THROUGH EARLY AFTERNOON BEFORE THE PRECIPITATION CHANGES TO RAIN. MEANWHILE...A FRONTAL SYSTEM ACROSS THE GULF STATES WILL GRADUALLY LIFT NORTHEAST AND ACROSS CENTRAL INDIANA EARLY THIS WEEKEND. THIS WILL BRING RAIN TO THE AREA...AS WELL AS COUPLE OF BRIEF CHANCES FOR SOME LIGHT FREEZING RAIN. THE RAIN WILL MOVE OUT OF THE AREA ON SATURDAY AND THE WEATHER SHOULD BE DRY UNTIL MONDAY WHEN ANOTHER SYSTEM BRINGS CHANCES FOR RAIN AND THEN SNOW MONDAY NIGHT. && .NEAR TERM /TODAY/... ISSUED AT 955 AM EST THU DEC 4 2014 PAP13 SOUNDINGS...BUFKIT...IND DUAL POL AND MOST IMPORTANTLY THE HUF OBS AND REPORTS OVER THE TERRE HAUTE AREA NECCESSITATE ADDING SNOW AND SLEET TO THE GRIDS THROUGH EARLY AFTERNOON. THE MIX SHOULD CHANGE TO ALL RAIN FROM SOUTHWEST TO NORTHEAST AND BECOME RAIN ACROSS ALL OF CENTRAL INDIANA AFTER 1 PM. ALSO BROUGHT POPS FURTHER NORTH BASED ON MORE MOIST PAP13 SOUNDINGS ALONG WITH 295 ISENTROPIC CONDENSATION PRESSURE DEFEICITS. PREVIOUS DISCUSSION FOLLOWS... CURRENTLY RADAR MOSAIC IS SHOWING WEAK ECHOES MOVING INTO SOUTHWESTERN INDIANA. UPSTREAM OBSERVATIONS SHOW SOME OF THIS IS REACHING THE GROUND IN THE FORM OF DRIZZLE OR VERY LIGHT RAIN...AND SOME IS NOT REACHING THE GROUND AT ALL. HRRR SEEMS TO HAVE A BETTER HANDLE ON THIS THAN OTHER MODELS AND THUS FOLLOWED IT FAIRLY CLOSELY...ADDING IN PATCHY DRIZZLE OR FREEZING DRIZZLE IN THE SOUTHWEST INITIALLY AND MOVING IN NORTHEAST OVER THE NEXT SEVERAL HOURS. HAVE THIS POTENTIAL REACHING THE INDY METRO AROUND 7-9 AM. WITH TEMPERATURES BELOW FREEZING CURRENTLY ACROSS MOST OF THE AREA DECIDED TO INCLUDE THE FREEZING DRIZZLE MENTION...BUT HAVE SEEN SOME WARMING AT THE SURFACE AS CLOUDS MOVE IN SO HOPEFULLY THIS WILL HELP MITIGATE ANY POTENTIAL ICING ISSUES. TEMPERATURES SHOULD MAKE IT ABOVE FREEZING ACROSS THE ENTIRE AREA BY MID MORNING AND AFTER THAT CHANCES FOR MEASURABLE RAIN WILL MOVE IN FROM THE SOUTHWEST AS AN UPPER WAVE APPROACHES HIGH PRESSURE MOVES OFF TO THE NORTHEAST. INCREASED POPS IN THE SOUTH FOR THE AFTERNOON FROM MOS BASED ON OUTPUT FROM RAPID UPDATE MODELS AND DECENT FORCING FROM THE QUICK MOVING UPPER WAVE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 423 AM EST THU DEC 4 2014 FORECAST FOCUS IS ON PRECIP CHANCES. MODELS IN PRETTY GOOD AGREEMENT AND GENERALLY STUCK CLOSE TO A CONSENSUS. FOR TONIGHT MODELS HAVE BACKED OFF SOME ON PRECIP CHANCES AS THE FIRST UPPER SHORTWAVE WILL BE PAST BUT THE NEXT ONE WILL NOT ARRIVE UNTIL FRIDAY MORNING. WITH THE FRONT FORMING ALONG OR JUST SOUTH OF THE OHIO RIVER WILL STILL HAVE SOME ISENTROPIC LIFT ESPECIALLY FURTHER SOUTH CLOSEST TO THE FRONT SO WILL MAINTAIN CHANCE POPS THERE AND TAPER TO SLIGHT CHANCE IN THE NORTH. POPS WILL INCREASE BY FRIDAY MORNING AS THE NEXT UPPER WAVE APPROACHES AND FRONTOGENESIS INCREASES ACROSS THE SOUTH. BY THE AFTERNOON THE SURFACE LOW WILL EJECT FROM THE PLAINS AND MOVE CLOSER BRINGING CATEGORICAL RAIN TO THE AREA. THIS WILL STAY IN PLACE DURING THE OVERNIGHT AS THE SURFACE LOW MOVES ALONG THE FRONT AND ALONG THE OHIO RIVER AND THEN THE UPPER TROUGH PASSES THROUGH EARLY SATURDAY MORNING. MODELS ARE MOVING THIS THROUGH A LITTLE FASTER AND THUS DECREASED POPS FOR SATURDAY MORNING KEEPING CHANCES ACROSS THE EAST TO DRY IN THE NORTHWEST AND BY AFTERNOON BROUGHT DRY WEATHER TO ALL BUT THE FAR EASTERN COUNTIES. SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN. FOR PRECIPITATION TYPE TONIGHT AND EARLY FRIDAY MORNING...A FEW HOURS OF FREEZING RAIN ARE POSSIBLE IN THE NORTHERN COUNTIES AS TEMPERATURES SHOULD DIP JUST BELOW FREEZING. NOT EXPECTING MUCH IN THE WAY OF ICE ACCUMULATION...BUT TEMPERATURES COULD REMAIN AT OR BELOW FREEZING IN THE NORTHERN COUNTIES UNTIL MID MORNING FRIDAY. ON RAINFALL TOTALS...COULD SEE MORE THAN AN INCH AND A HALF ACROSS PARTS OF THE AREA BETWEEN FRIDAY AND FRIDAY NIGHT WITH STRONG FORCING...GOOD LOW LEVEL JET BRING IN AMPLE MOISTURE AND OVERALL SLOW SYSTEM MOTION. HOWEVER PLACEMENT OF THE HEAVIEST AXIS IS A LITTLE TRICKY WITH MODELS VARYING IT FROM NEAR THE OHIO RIVER TO ACROSS THE CENTRAL PART OF THE FORECAST AREA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR THE 041800Z TAFS/... ISSUED AT 1146 AM EST THU DEC 4 2014 AREA OF MIXED PRECIPITATION CONTINUES TO MOVE MAINLY ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. THIS MORNING/S UPPER AIR INDICATED A RATHER LARGE ELEVATED WARM LAYER...BUT ALSO VERY DRY AIR AT THAT LEVEL. EVAPORATIVE COOLING PROCESSES HAVE KEPT PRECIPITATION MAINLY IN THE FORM OF SNOW ALONG THE NORTHERN FRINGES OF THE PRECIPITATION AREA. APPEARS PRECIPITATION AREA WILL BE PASSING OFF TO THE EAST OF THE TAF SITES BY 042000Z. WILL KEEP SOME OCCASIONAL IFR VISIBILITY RESTRICTIONS IN SNOW/SLEET...MAINLY AT KIND...BASED ON SURFACE OBSERVATIONS. EXPECTING MAINLY RAIN OR A RAIN/SLEET MIX FARTHER SOUTH AT KBMG. KLAF MAY SEE A BRIEF PERIOD OF LIGHT SNOW/SLEET EARLY THIS AFTERNOON...BUT OVERALL MOST OF THE PRECIPITATION SHOULD REMAIN TO THE SOUTH OF KLAF. CEILINGS THIS AFTERNOON IN THE 025-050 RANGE SHOULD GRADUALLY FALL BELOW 020 EARLY THIS EVENING FROM SOUTH TO NORTH...AND WILL PROBABLY FALL INTO THE IFR CATEGORY LATER TONIGHT UNDER CONTINUED WARM ADVECTION. SURFACE WINDS GENERALLY 090-110 AT 6-8 KTS THIS AFTERNOON SHOULD BECOME LIGHT AFTER DARK. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP/MK NEAR TERM...CP/MK SHORT TERM...CP LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
955 AM EST THU DEC 4 2014 .UPDATE... THE SYNOPSIS AND NEAR TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 950 AM EST THU DEC 4 2014 AN UPPER WAVE AND MOISTENING SOUTHWEST UPGLIDE WILL BRING MIXED PRECIPITATION TO CENTRAL INDIANA THROUGH EARLY AFTERNOON BEFORE THE PRECIPITATION CHANGES TO RAIN. MEANWHILE...A FRONTAL SYSTEM ACROSS THE GULF STATES WILL GRADUALLY LIFT NORTHEAST AND ACROSS CENTRAL INDIANA EARLY THIS WEEKEND. THIS WILL BRING RAIN TO THE AREA...AS WELL AS COUPLE OF BRIEF CHANCES FOR SOME LIGHT FREEZING RAIN. THE RAIN WILL MOVE OUT OF THE AREA ON SATURDAY AND THE WEATHER SHOULD BE DRY UNTIL MONDAY WHEN ANOTHER SYSTEM BRINGS CHANCES FOR RAIN AND THEN SNOW MONDAY NIGHT. && .NEAR TERM /TODAY/... ISSUED AT 955 AM EST THU DEC 4 2014 PAP13 SOUNDINGS...BUFKIT...IND DUAL POL AND MOST IMPORTANTLY THE HUF OBS AND REPORTS OVER THE TERRE HAUTE AREA NECCESSITATE ADDING SNOW AND SLEET TO THE GRIDS THROUGH EARLY AFTERNOON. THE MIX SHOULD CHANGE TO ALL RAIN FROM SOUTHWEST TO NORTHEAST AND BECOME RAIN ACROSS ALL OF CENTRAL INDIANA AFTER 1 PM. ALSO BROUGHT POPS FURTHER NORTH BASED ON MORE MOIST PAP13 SOUNDINGS ALONG WITH 295 ISENTROPIC CONDENSATION PRESSURE DEFEICITS. PREVIOUS DISCUSSION FOLLOWS... CURRENTLY RADAR MOSAIC IS SHOWING WEAK ECHOES MOVING INTO SOUTHWESTERN INDIANA. UPSTREAM OBSERVATIONS SHOW SOME OF THIS IS REACHING THE GROUND IN THE FORM OF DRIZZLE OR VERY LIGHT RAIN...AND SOME IS NOT REACHING THE GROUND AT ALL. HRRR SEEMS TO HAVE A BETTER HANDLE ON THIS THAN OTHER MODELS AND THUS FOLLOWED IT FAIRLY CLOSELY...ADDING IN PATCHY DRIZZLE OR FREEZING DRIZZLE IN THE SOUTHWEST INITIALLY AND MOVING IN NORTHEAST OVER THE NEXT SEVERAL HOURS. HAVE THIS POTENTIAL REACHING THE INDY METRO AROUND 7-9 AM. WITH TEMPERATURES BELOW FREEZING CURRENTLY ACROSS MOST OF THE AREA DECIDED TO INCLUDE THE FREEZING DRIZZLE MENTION...BUT HAVE SEEN SOME WARMING AT THE SURFACE AS CLOUDS MOVE IN SO HOPEFULLY THIS WILL HELP MITIGATE ANY POTENTIAL ICING ISSUES. TEMPERATURES SHOULD MAKE IT ABOVE FREEZING ACROSS THE ENTIRE AREA BY MID MORNING AND AFTER THAT CHANCES FOR MEASURABLE RAIN WILL MOVE IN FROM THE SOUTHWEST AS AN UPPER WAVE APPROACHES HIGH PRESSURE MOVES OFF TO THE NORTHEAST. INCREASED POPS IN THE SOUTH FOR THE AFTERNOON FROM MOS BASED ON OUTPUT FROM RAPID UPDATE MODELS AND DECENT FORCING FROM THE QUICK MOVING UPPER WAVE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 423 AM EST THU DEC 4 2014 FORECAST FOCUS IS ON PRECIP CHANCES. MODELS IN PRETTY GOOD AGREEMENT AND GENERALLY STUCK CLOSE TO A CONSENSUS. FOR TONIGHT MODELS HAVE BACKED OFF SOME ON PRECIP CHANCES AS THE FIRST UPPER SHORTWAVE WILL BE PAST BUT THE NEXT ONE WILL NOT ARRIVE UNTIL FRIDAY MORNING. WITH THE FRONT FORMING ALONG OR JUST SOUTH OF THE OHIO RIVER WILL STILL HAVE SOME ISENTROPIC LIFT ESPECIALLY FURTHER SOUTH CLOSEST TO THE FRONT SO WILL MAINTAIN CHANCE POPS THERE AND TAPER TO SLIGHT CHANCE IN THE NORTH. POPS WILL INCREASE BY FRIDAY MORNING AS THE NEXT UPPER WAVE APPROACHES AND FRONTOGENESIS INCREASES ACROSS THE SOUTH. BY THE AFTERNOON THE SURFACE LOW WILL EJECT FROM THE PLAINS AND MOVE CLOSER BRINGING CATEGORICAL RAIN TO THE AREA. THIS WILL STAY IN PLACE DURING THE OVERNIGHT AS THE SURFACE LOW MOVES ALONG THE FRONT AND ALONG THE OHIO RIVER AND THEN THE UPPER TROUGH PASSES THROUGH EARLY SATURDAY MORNING. MODELS ARE MOVING THIS THROUGH A LITTLE FASTER AND THUS DECREASED POPS FOR SATURDAY MORNING KEEPING CHANCES ACROSS THE EAST TO DRY IN THE NORTHWEST AND BY AFTERNOON BROUGHT DRY WEATHER TO ALL BUT THE FAR EASTERN COUNTIES. SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN. FOR PRECIPITATION TYPE TONIGHT AND EARLY FRIDAY MORNING...A FEW HOURS OF FREEZING RAIN ARE POSSIBLE IN THE NORTHERN COUNTIES AS TEMPERATURES SHOULD DIP JUST BELOW FREEZING. NOT EXPECTING MUCH IN THE WAY OF ICE ACCUMULATION...BUT TEMPERATURES COULD REMAIN AT OR BELOW FREEZING IN THE NORTHERN COUNTIES UNTIL MID MORNING FRIDAY. ON RAINFALL TOTALS...COULD SEE MORE THAN AN INCH AND A HALF ACROSS PARTS OF THE AREA BETWEEN FRIDAY AND FRIDAY NIGHT WITH STRONG FORCING...GOOD LOW LEVEL JET BRING IN AMPLE MOISTURE AND OVERALL SLOW SYSTEM MOTION. HOWEVER PLACEMENT OF THE HEAVIEST AXIS IS A LITTLE TRICKY WITH MODELS VARYING IT FROM NEAR THE OHIO RIVER TO ACROSS THE CENTRAL PART OF THE FORECAST AREA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR THE 041500Z KIND TAF UPDATE/... ISSUED AT 936 AM EST THU DEC 4 2014 THIS MORNING/S UPPER AIR INDICATES A RATHER LARGE ELEVATED WARM LAYER...BUT ALSO VERY DRY AIR AT THAT LEVEL. THINK EVAPORATIVE COOLING PROCESSES MAY KEEP PRECIPITATION MORE OF THE FROZEN TYPE A LITTLE LONGER AT KIND. WILL KEEP THE SNOW/SLEET MIX IN THE FORECAST THROUGH 041800Z. SOME OF THE HEAVIER ECHOES ARE BEGINNING TO PRODUCE LOCALIZED IFR VISIBILITY RESTRICTIONS...SO WILL LOWER THE VISIBILITY FORECAST SOME. BRIEF PERIOD OF FREEZING RAIN STILL POSSIBLE THROUGH ABOUT MIDDAY AT KIND...BUT THE WINDOW APPEARS TO BE NARROWING. PREVIOUS DISCUSSION FOLLOWS. RADAR INDICATES SOME PRECIPITATION MOVING INTO THE WEST CENTRAL AND SOUTHWEST PARTS OF THE FORECAST AREA AT THIS TIME. NOT SEEING ANY SURFACE REPORTS OF ANYTHING HITTING THE GROUND...BUT BASED ON THE INTENSITY OF SOME OF THE ECHOES...THINK AT LEAST SOME PATCHY PRECIPITATION IS REACHING THE GROUND. THICKNESSES OFF OF THE SHORT TERM MODELS SUGGEST MAINLY SNOW OR SLEET...WITH MAYBE A SMALL WINDOW OF FREEZING RAIN POTENTIAL AFTER SUNRISE THROUGH ABOUT 041600Z. PRECIPITATION SHOULD BE LIGHT ENOUGH TO NOT IMPACT VISIBILITIES TOO MUCH. BETTER CHANCES FOR MORE ORGANIZED RAIN LATER THIS AFTERNOON. CEILINGS EXPECTED TO GRADUALLY FALL TODAY THROUGH 050...REACHING MVFR OVER THE SOUTHERN TAF SITES BY LATE AFTERNOON. LIGHT SURFACE WINDS EARLY THIS MORNING SHOULD BECOME 090-110 DEGREES AT 6-9 KTS BY MIDDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP/MK NEAR TERM...CP/MK SHORT TERM...CP LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
936 AM EST THU DEC 4 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 423 AM EST THU DEC 4 2014 AN ACTIVE WEATHER PATTERN IS IN PLACE FOR THE NEXT COUPLE OF DAYS AS LOW PRESSURE FORMS OVER THE PLAINS AND BRINGS A FRONTAL SYSTEM THROUGH CENTRAL INDIANA. THIS WILL BRING RAIN TO THE AREA...AS WELL AS COUPLE OF BRIEF CHANCES FOR SOME LIGHT FREEZING RAIN IN AREAS. RAIN WILL MOVE OUT OF THE AREA ON SATURDAY AND THE WEATHER SHOULD BE DRY UNTIL MONDAY WHEN ANOTHER SYSTEM BRINGS CHANCES FOR RAIN AND THEN SNOW MONDAY NIGHT. && .NEAR TERM /EARLY THIS MORNING AND TODAY/... ISSUED AT 423 AM EST THU DEC 4 2014 CURRENTLY RADAR MOSAIC IS SHOWING WEAK ECHOES MOVING INTO SOUTHWESTERN INDIANA. UPSTREAM OBSERVATIONS SHOW SOME OF THIS IS REACHING THE GROUND IN THE FORM OF DRIZZLE OR VERY LIGHT RAIN...AND SOME IS NOT REACHING THE GROUND AT ALL. HRRR SEEMS TO HAVE A BETTER HANDLE ON THIS THAN OTHER MODELS AND THUS FOLLOWED IT FAIRLY CLOSELY...ADDING IN PATCHY DRIZZLE OR FREEZING DRIZZLE IN THE SOUTHWEST INITIALLY AND MOVING IN NORTHEAST OVER THE NEXT SEVERAL HOURS. HAVE THIS POTENTIAL REACHING THE INDY METRO AROUND 7-9 AM. WITH TEMPERATURES BELOW FREEZING CURRENTLY ACROSS MOST OF THE AREA DECIDED TO INCLUDE THE FREEZING DRIZZLE MENTION...BUT HAVE SEEN SOME WARMING AT THE SURFACE AS CLOUDS MOVE IN SO HOPEFULLY THIS WILL HELP MITIGATE ANY POTENTIAL ICING ISSUES. TEMPERATURES SHOULD MAKE IT ABOVE FREEZING ACROSS THE ENTIRE AREA BY MID MORNING AND AFTER THAT CHANCES FOR MEASURABLE RAIN WILL MOVE IN FROM THE SOUTHWEST AS AN UPPER WAVE APPROACHES HIGH PRESSURE MOVES OFF TO THE NORTHEAST. INCREASED POPS IN THE SOUTH FOR THE AFTERNOON FROM MOS BASED ON OUTPUT FROM RAPID UPDATE MODELS AND DECENT FORCING FROM THE QUICK MOVING UPPER WAVE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 423 AM EST THU DEC 4 2014 FORECAST FOCUS IS ON PRECIP CHANCES. MODELS IN PRETTY GOOD AGREEMENT AND GENERALLY STUCK CLOSE TO A CONSENSUS. FOR TONIGHT MODELS HAVE BACKED OFF SOME ON PRECIP CHANCES AS THE FIRST UPPER SHORTWAVE WILL BE PAST BUT THE NEXT ONE WILL NOT ARRIVE UNTIL FRIDAY MORNING. WITH THE FRONT FORMING ALONG OR JUST SOUTH OF THE OHIO RIVER WILL STILL HAVE SOME ISENTROPIC LIFT ESPECIALLY FURTHER SOUTH CLOSEST TO THE FRONT SO WILL MAINTAIN CHANCE POPS THERE AND TAPER TO SLIGHT CHANCE IN THE NORTH. POPS WILL INCREASE BY FRIDAY MORNING AS THE NEXT UPPER WAVE APPROACHES AND FRONTOGENESIS INCREASES ACROSS THE SOUTH. BY THE AFTERNOON THE SURFACE LOW WILL EJECT FROM THE PLAINS AND MOVE CLOSER BRINGING CATEGORICAL RAIN TO THE AREA. THIS WILL STAY IN PLACE DURING THE OVERNIGHT AS THE SURFACE LOW MOVES ALONG THE FRONT AND ALONG THE OHIO RIVER AND THEN THE UPPER TROUGH PASSES THROUGH EARLY SATURDAY MORNING. MODELS ARE MOVING THIS THROUGH A LITTLE FASTER AND THUS DECREASED POPS FOR SATURDAY MORNING KEEPING CHANCES ACROSS THE EAST TO DRY IN THE NORTHWEST AND BY AFTERNOON BROUGHT DRY WEATHER TO ALL BUT THE FAR EASTERN COUNTIES. SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN. FOR PRECIPITATION TYPE TONIGHT AND EARLY FRIDAY MORNING...A FEW HOURS OF FREEZING RAIN ARE POSSIBLE IN THE NORTHERN COUNTIES AS TEMPERATURES SHOULD DIP JUST BELOW FREEZING. NOT EXPECTING MUCH IN THE WAY OF ICE ACCUMULATION...BUT TEMPERATURES COULD REMAIN AT OR BELOW FREEZING IN THE NORTHERN COUNTIES UNTIL MID MORNING FRIDAY. ON RAINFALL TOTALS...COULD SEE MORE THAN AN INCH AND A HALF ACROSS PARTS OF THE AREA BETWEEN FRIDAY AND FRIDAY NIGHT WITH STRONG FORCING...GOOD LOW LEVEL JET BRING IN AMPLE MOISTURE AND OVERALL SLOW SYSTEM MOTION. HOWEVER PLACEMENT OF THE HEAVIEST AXIS IS A LITTLE TRICKY WITH MODELS VARYING IT FROM NEAR THE OHIO RIVER TO ACROSS THE CENTRAL PART OF THE FORECAST AREA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR THE 041500Z KIND TAF UPDATE/... ISSUED AT 936 AM EST THU DEC 4 2014 THIS MORNING/S UPPER AIR INDICATES A RATHER LARGE ELEVATED WARM LAYER...BUT ALSO VERY DRY AIR AT THAT LEVEL. THINK EVAPORATIVE COOLING PROCESSES MAY KEEP PRECIPITATION MORE OF THE FROZEN TYPE A LITTLE LONGER AT KIND. WILL KEEP THE SNOW/SLEET MIX IN THE FORECAST THROUGH 041800Z. SOME OF THE HEAVIER ECHOES ARE BEGINNING TO PRODUCE LOCALIZED IFR VISIBILITY RESTRICTIONS...SO WILL LOWER THE VISIBILITY FORECAST SOME. BRIEF PERIOD OF FREEZING RAIN STILL POSSIBLE THROUGH ABOUT MIDDAY AT KIND...BUT THE WINDOW APPEARS TO BE NARROWING. PREVIOUS DISCUSSION FOLLOWS. RADAR INDICATES SOME PRECIPITATION MOVING INTO THE WEST CENTRAL AND SOUTHWEST PARTS OF THE FORECAST AREA AT THIS TIME. NOT SEEING ANY SURFACE REPORTS OF ANYTHING HITTING THE GROUND...BUT BASED ON THE INTENSITY OF SOME OF THE ECHOES...THINK AT LEAST SOME PATCHY PRECIPITATION IS REACHING THE GROUND. THICKNESSES OFF OF THE SHORT TERM MODELS SUGGEST MAINLY SNOW OR SLEET...WITH MAYBE A SMALL WINDOW OF FREEZING RAIN POTENTIAL AFTER SUNRISE THROUGH ABOUT 041600Z. PRECIPITATION SHOULD BE LIGHT ENOUGH TO NOT IMPACT VISIBILITIES TOO MUCH. BETTER CHANCES FOR MORE ORGANIZED RAIN LATER THIS AFTERNOON. CEILINGS EXPECTED TO GRADUALLY FALL TODAY THROUGH 050...REACHING MVFR OVER THE SOUTHERN TAF SITES BY LATE AFTERNOON. LIGHT SURFACE WINDS EARLY THIS MORNING SHOULD BECOME 090-110 DEGREES AT 6-9 KTS BY MIDDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
637 AM EST THU DEC 4 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 423 AM EST THU DEC 4 2014 AN ACTIVE WEATHER PATTERN IS IN PLACE FOR THE NEXT COUPLE OF DAYS AS LOW PRESSURE FORMS OVER THE PLAINS AND BRINGS A FRONTAL SYSTEM THROUGH CENTRAL INDIANA. THIS WILL BRING RAIN TO THE AREA...AS WELL AS COUPLE OF BRIEF CHANCES FOR SOME LIGHT FREEZING RAIN IN AREAS. RAIN WILL MOVE OUT OF THE AREA ON SATURDAY AND THE WEATHER SHOULD BE DRY UNTIL MONDAY WHEN ANOTHER SYSTEM BRINGS CHANCES FOR RAIN AND THEN SNOW MONDAY NIGHT. && .NEAR TERM /EARLY THIS MORNING AND TODAY/... ISSUED AT 423 AM EST THU DEC 4 2014 CURRENTLY RADAR MOSAIC IS SHOWING WEAK ECHOES MOVING INTO SOUTHWESTERN INDIANA. UPSTREAM OBSERVATIONS SHOW SOME OF THIS IS REACHING THE GROUND IN THE FORM OF DRIZZLE OR VERY LIGHT RAIN...AND SOME IS NOT REACHING THE GROUND AT ALL. HRRR SEEMS TO HAVE A BETTER HANDLE ON THIS THAN OTHER MODELS AND THUS FOLLOWED IT FAIRLY CLOSELY...ADDING IN PATCHY DRIZZLE OR FREEZING DRIZZLE IN THE SOUTHWEST INITIALLY AND MOVING IN NORTHEAST OVER THE NEXT SEVERAL HOURS. HAVE THIS POTENTIAL REACHING THE INDY METRO AROUND 7-9 AM. WITH TEMPERATURES BELOW FREEZING CURRENTLY ACROSS MOST OF THE AREA DECIDED TO INCLUDE THE FREEZING DRIZZLE MENTION...BUT HAVE SEEN SOME WARMING AT THE SURFACE AS CLOUDS MOVE IN SO HOPEFULLY THIS WILL HELP MITIGATE ANY POTENTIAL ICING ISSUES. TEMPERATURES SHOULD MAKE IT ABOVE FREEZING ACROSS THE ENTIRE AREA BY MID MORNING AND AFTER THAT CHANCES FOR MEASURABLE RAIN WILL MOVE IN FROM THE SOUTHWEST AS AN UPPER WAVE APPROACHES HIGH PRESSURE MOVES OFF TO THE NORTHEAST. INCREASED POPS IN THE SOUTH FOR THE AFTERNOON FROM MOS BASED ON OUTPUT FROM RAPID UPDATE MODELS AND DECENT FORCING FROM THE QUICK MOVING UPPER WAVE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 423 AM EST THU DEC 4 2014 FORECAST FOCUS IS ON PRECIP CHANCES. MODELS IN PRETTY GOOD AGREEMENT AND GENERALLY STUCK CLOSE TO A CONSENSUS. FOR TONIGHT MODELS HAVE BACKED OFF SOME ON PRECIP CHANCES AS THE FIRST UPPER SHORTWAVE WILL BE PAST BUT THE NEXT ONE WILL NOT ARRIVE UNTIL FRIDAY MORNING. WITH THE FRONT FORMING ALONG OR JUST SOUTH OF THE OHIO RIVER WILL STILL HAVE SOME ISENTROPIC LIFT ESPECIALLY FURTHER SOUTH CLOSEST TO THE FRONT SO WILL MAINTAIN CHANCE POPS THERE AND TAPER TO SLIGHT CHANCE IN THE NORTH. POPS WILL INCREASE BY FRIDAY MORNING AS THE NEXT UPPER WAVE APPROACHES AND FRONTOGENESIS INCREASES ACROSS THE SOUTH. BY THE AFTERNOON THE SURFACE LOW WILL EJECT FROM THE PLAINS AND MOVE CLOSER BRINGING CATEGORICAL RAIN TO THE AREA. THIS WILL STAY IN PLACE DURING THE OVERNIGHT AS THE SURFACE LOW MOVES ALONG THE FRONT AND ALONG THE OHIO RIVER AND THEN THE UPPER TROUGH PASSES THROUGH EARLY SATURDAY MORNING. MODELS ARE MOVING THIS THROUGH A LITTLE FASTER AND THUS DECREASED POPS FOR SATURDAY MORNING KEEPING CHANCES ACROSS THE EAST TO DRY IN THE NORTHWEST AND BY AFTERNOON BROUGHT DRY WEATHER TO ALL BUT THE FAR EASTERN COUNTIES. SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN. FOR PRECIPITATION TYPE TONIGHT AND EARLY FRIDAY MORNING...A FEW HOURS OF FREEZING RAIN ARE POSSIBLE IN THE NORTHERN COUNTIES AS TEMPERATURES SHOULD DIP JUST BELOW FREEZING. NOT EXPECTING MUCH IN THE WAY OF ICE ACCUMULATION...BUT TEMPERATURES COULD REMAIN AT OR BELOW FREEZING IN THE NORTHERN COUNTIES UNTIL MID MORNING FRIDAY. ON RAINFALL TOTALS...COULD SEE MORE THAN AN INCH AND A HALF ACROSS PARTS OF THE AREA BETWEEN FRIDAY AND FRIDAY NIGHT WITH STRONG FORCING...GOOD LOW LEVEL JET BRING IN AMPLE MOISTURE AND OVERALL SLOW SYSTEM MOTION. HOWEVER PLACEMENT OF THE HEAVIEST AXIS IS A LITTLE TRICKY WITH MODELS VARYING IT FROM NEAR THE OHIO RIVER TO ACROSS THE CENTRAL PART OF THE FORECAST AREA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR THE 041200Z TAFS/... ISSUED AT 637 AM EST THU DEC 4 2014 RADAR INDICATES SOME PRECIPITATION MOVING INTO THE WEST CENTRAL AND SOUTHWEST PARTS OF THE FORECAST AREA AT THIS TIME. NOT SEEING ANY SURFACE REPORTS OF ANYTHING HITTING THE GROUND...BUT BASED ON THE INTENSITY OF SOME OF THE ECHOES...THINK AT LEAST SOME PATCHY PRECIPITATION IS REACHING THE GROUND. THICKNESSES OFF OF THE SHORT TERM MODELS SUGGEST MAINLY SNOW OR SLEET...WITH MAYBE A SMALL WINDOW OF FREEZING RAIN POTENTIAL AFTER SUNRISE THROUGH ABOUT 041600Z. PRECIPITATION SHOULD BE LIGHT ENOUGH TO NOT IMPACT VISIBILITIES TOO MUCH. BETTER CHANCES FOR MORE ORGANIZED RAIN LATER THIS AFTERNOON. CEILINGS EXPECTED TO GRADUALLY FALL TODAY THROUGH 050...REACHING MVFR OVER THE SOUTHERN TAF SITES BY LATE AFTERNOON. LIGHT SURFACE WINDS EARLY THIS MORNING SHOULD BECOME 090-110 DEGREES AT 6-9 KTS BY MIDDAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
425 AM EST THU DEC 4 2014 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 423 AM EST THU DEC 4 2014 AN ACTIVE WEATHER PATTERN IS IN PLACE FOR THE NEXT COUPLE OF DAYS AS LOW PRESSURE FORMS OVER THE PLAINS AND BRINGS A FRONTAL SYSTEM THROUGH CENTRAL INDIANA. THIS WILL BRING RAIN TO THE AREA...AS WELL AS COUPLE OF BRIEF CHANCES FOR SOME LIGHT FREEZING RAIN IN AREAS. RAIN WILL MOVE OUT OF THE AREA ON SATURDAY AND THE WEATHER SHOULD BE DRY UNTIL MONDAY WHEN ANOTHER SYSTEM BRINGS CHANCES FOR RAIN AND THEN SNOW MONDAY NIGHT. && .NEAR TERM /EARLY THIS MORNING AND TODAY/... ISSUED AT 423 AM EST THU DEC 4 2014 CURRENTLY RADAR MOSAIC IS SHOWING WEAK ECHOES MOVING INTO SOUTHWESTERN INDIANA. UPSTREAM OBSERVATIONS SHOW SOME OF THIS IS REACHING THE GROUND IN THE FORM OF DRIZZLE OR VERY LIGHT RAIN...AND SOME IS NOT REACHING THE GROUND AT ALL. HRRR SEEMS TO HAVE A BETTER HANDLE ON THIS THAN OTHER MODELS AND THUS FOLLOWED IT FAIRLY CLOSELY...ADDING IN PATCHY DRIZZLE OR FREEZING DRIZZLE IN THE SOUTHWEST INITIALLY AND MOVING IN NORTHEAST OVER THE NEXT SEVERAL HOURS. HAVE THIS POTENTIAL REACHING THE INDY METRO AROUND 7-9 AM. WITH TEMPERATURES BELOW FREEZING CURRENTLY ACROSS MOST OF THE AREA DECIDED TO INCLUDE THE FREEZING DRIZZLE MENTION...BUT HAVE SEEN SOME WARMING AT THE SURFACE AS CLOUDS MOVE IN SO HOPEFULLY THIS WILL HELP MITIGATE ANY POTENTIAL ICING ISSUES. TEMPERATURES SHOULD MAKE IT ABOVE FREEZING ACROSS THE ENTIRE AREA BY MID MORNING AND AFTER THAT CHANCES FOR MEASURABLE RAIN WILL MOVE IN FROM THE SOUTHWEST AS AN UPPER WAVE APPROACHES HIGH PRESSURE MOVES OFF TO THE NORTHEAST. INCREASED POPS IN THE SOUTH FOR THE AFTERNOON FROM MOS BASED ON OUTPUT FROM RAPID UPDATE MODELS AND DECENT FORCING FROM THE QUICK MOVING UPPER WAVE. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 423 AM EST THU DEC 4 2014 FORECAST FOCUS IS ON PRECIP CHANCES. MODELS IN PRETTY GOOD AGREEMENT AND GENERALLY STUCK CLOSE TO A CONSENSUS. FOR TONIGHT MODELS HAVE BACKED OFF SOME ON PRECIP CHANCES AS THE FIRST UPPER SHORTWAVE WILL BE PAST BUT THE NEXT ONE WILL NOT ARRIVE UNTIL FRIDAY MORNING. WITH THE FRONT FORMING ALONG OR JUST SOUTH OF THE OHIO RIVER WILL STILL HAVE SOME ISENTROPIC LIFT ESPECIALLY FURTHER SOUTH CLOSEST TO THE FRONT SO WILL MAINTAIN CHANCE POPS THERE AND TAPER TO SLIGHT CHANCE IN THE NORTH. POPS WILL INCREASE BY FRIDAY MORNING AS THE NEXT UPPER WAVE APPROACHES AND FRONTOGENESIS INCREASES ACROSS THE SOUTH. BY THE AFTERNOON THE SURFACE LOW WILL EJECT FROM THE PLAINS AND MOVE CLOSER BRINGING CATEGORICAL RAIN TO THE AREA. THIS WILL STAY IN PLACE DURING THE OVERNIGHT AS THE SURFACE LOW MOVES ALONG THE FRONT AND ALONG THE OHIO RIVER AND THEN THE UPPER TROUGH PASSES THROUGH EARLY SATURDAY MORNING. MODELS ARE MOVING THIS THROUGH A LITTLE FASTER AND THUS DECREASED POPS FOR SATURDAY MORNING KEEPING CHANCES ACROSS THE EAST TO DRY IN THE NORTHWEST AND BY AFTERNOON BROUGHT DRY WEATHER TO ALL BUT THE FAR EASTERN COUNTIES. SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE BUILDS IN. FOR PRECIPITATION TYPE TONIGHT AND EARLY FRIDAY MORNING...A FEW HOURS OF FREEZING RAIN ARE POSSIBLE IN THE NORTHERN COUNTIES AS TEMPERATURES SHOULD DIP JUST BELOW FREEZING. NOT EXPECTING MUCH IN THE WAY OF ICE ACCUMULATION...BUT TEMPERATURES COULD REMAIN AT OR BELOW FREEZING IN THE NORTHERN COUNTIES UNTIL MID MORNING FRIDAY. ON RAINFALL TOTALS...COULD SEE MORE THAN AN INCH AND A HALF ACROSS PARTS OF THE AREA BETWEEN FRIDAY AND FRIDAY NIGHT WITH STRONG FORCING...GOOD LOW LEVEL JET BRING IN AMPLE MOISTURE AND OVERALL SLOW SYSTEM MOTION. HOWEVER PLACEMENT OF THE HEAVIEST AXIS IS A LITTLE TRICKY WITH MODELS VARYING IT FROM NEAR THE OHIO RIVER TO ACROSS THE CENTRAL PART OF THE FORECAST AREA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR 040600Z TAF ISSUANCE/... ISSUED AT 1245 AM EST THU DEC 4 2014 VFR CONDITIONS EXPECTED THROUGH THIS MORNING...DETERIORATING CONDITIONS THIS AFTERNOON AND EVENING WITH PRECIPITATION. HIGH CLOUDS CONTINUE TO INCREASE EARLY THIS MORNING AS MOISTURE ALOFT SPREADS INTO THE REGION. LIGHT WINDS WILL GRADUALLY SET UP FROM THE NORTHEAST LATE TONIGHT AS A FRONTAL BOUNDARY MOVES INTO THE TENNESSEE VALLEY. LIGHT PRECIPITATION WILL EXPAND NORTHEAST THROUGH THE LOWER OHIO VALLEY AND INTO CENTRAL INDIANA DURING THE MORNING. HI RES WRF-ARW AND NMM ALONG WITH THE HRRR ALL BRING LIGHT PRECIP INTO THE I-70 CORRIDOR BY LATE MORNING. HAVE BUMPED UP VCSH MENTION AT KBMG/HUF/KIND BETWEEN 12-14Z WITH PREVAILING LIGHT RAIN DEVELOPING AT ALL SITES BY LATE MORNING. IN ADDITION WITH COLDER NEAR SURFACE AIR PRESENT IN THE MORNING...MAY SEE A BRIEF PERIOD OF LIGHT FREEZING DRIZZLE/RAIN AT THE ONSET AT BOTH KBMG AND KHUF BEFORE WARMING ENOUGH TO SUPPORT RAIN. WILL CONTINUE TO MONITOR SURFACE TEMP TRENDS OVER THE NEXT FEW HOURS. MODEL SOUNDINGS INDICATE DRIER AIR WITHIN THE BOUNDARY LAYER WILL BE SLOW TO SHIFT NORTH WHICH MAY LIMIT PRECIP INITIALLY...BUT STRONGER SURGE OF ISENTROPIC LIFT DURING THE AFTERNOON SHOULD ALLOW LOWER MVFR CEILINGS TO EXPAND NORTH. CEILINGS WILL SETTLE BETWEEN 1500-2000FT BY THE EVENING WITH LOWER VISIBILITIES IN SCATTERED LIGHT SHOWERS AND/OR DRIZZLE. EASTERLY WINDS AT 5-10KTS ARE EXPECTED FOR MUCH OF THE DAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
230 AM EST THU DEC 4 2014 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 317 PM EST WED DEC 3 2014 HIGH PRESSURE WILL BRING DRY CONDITIONS TO CENTRAL INDIANA TODAY AND TONIGHT. HOWEVER...RAIN/FREEZING RAIN WILL BE BACK IN THE FORECAST BY THURSDAY AS MOISTURE INCREASES AHEAD OF A FRONTAL BOUNDARY TO THE SOUTH. THIS SURFACE FRONTAL BOUNDARY WILL COMBINE WITH AN UPPER LEVEL TROUGH BY FRIDAY NIGHT TO PRODUCE WIDESPREAD RAIN INTO SATURDAY. AFTER THAT...A DRY PERIOD WILL RETURN FOR THE SECOND HALF OF THE WEEKEND. FURTHER OUT...A STRONG UPPER LEVEL LOW IS PROGGED TO AFFECT THE AREA ON MONDAY. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 957 PM EST WED DEC 3 2014 TEMPERATURES DROPPED QUICKLY THIS EVENING WHERE CIRRUS THINNED OUT...BUT SATELLITE SHOWS THICKER CIRRUS MOVING INTO THE AREA AT THE MOMENT. THUS DO NOT EXPECT TEMPERATURES TO FALL AS FAST...AND THEY MAY LEVEL OFF IN SOME AREAS WHERE CIRRUS IS THICKEST. THUS MADE NO CHANGES TO LOW TEMPERATURES...BUT DID ADJUST HOURLY READINGS TO REFLECT CURRENT TRENDS. ADJUSTED SKY COVER UP SOME ALSO BASED ON LATEST SATELLITE IMAGES. PRECIPITATION STILL LOOKS TO HOLD OFF UNTIL AFTER 12Z. PREVIOUS DISCUSSION FOLLOWS... CALM AND DRY CONDITIONS WILL PREVAIL TONIGHT AS HIGH PRESSURE STRENGTHENS OVER THE MIDWEST. DRIER AIR HAS BEEN STREAMING INTO THE FORECAST AREA ALL DAY FROM THE NORTHWEST...AND WILL CONTINUE TO THROUGH THE NIGHT. AS A RESULT...PARTLY CLOUDY SKIES CAN BE EXPECTED TONIGHT WITH LOWS IN THE 20S DUE TO THE RADIATIONAL COOLING. MODELS ARE IN AGREEMENT IN REGARD TO THE RADIATIONAL COOLING...SO STUCK CLOSE TO GUIDANCE. && .SHORT TERM /TOMORROW THROUGH SATURDAY/... ISSUED AT 957 PM EST WED DEC 3 2014 BASED ON LATEST MODEL DATA...TEMPERATURES IN THE SOUTHERN FORECAST AREA MAY RISE A BIT FASTER THAN THOUGHT ON THURSDAY MORNING. THUS CHANGED PRECIPITATION TYPE TO FREEZING RAIN OR RAIN FOR NOW. PREVIOUS DISCUSSION FOLLOWS... THE MAIN FOCUS OF THE SHORT TERM PERIOD WILL BE PRECIP CHANCES AND TYPES WITH FRONTAL BOUNDARY TO THE SOUTH. PRECIP WILL OVERSPREAD CENTRAL INDIANA FROM THE SOUTHWEST TO NORTHEAST STARTING TOMORROW MORNING AS ISENTROPIC LIFT STRENGTHENS OVER THE MID MISSISSIPPI VALLEY. THE MAIN CHALLENGE DURING THIS PERIOD WILL BE PRECIP TYPE. A BRIEF PERIOD OF FREEZING RAIN OVER THE SOUTHERN COUNTIES WILL BE POSSIBLE EARLY THURSDAY MORNING...BUT THIS WILL QUICKLY TRANSITION TO RAIN BY MID MORNING AS TEMPERATURES INCREASE. RAIN WILL CONTINUE THROUGH THE DAY...BUT IT WILL BECOME A LITTLE TRICKY OVERNIGHT. MODELS ARE TRENDING TOWARD SOME WEAK WARM ADVECTION FROM THE SOUTH ON THURSDAY NIGHT...BUT CONFIDENCE IS LOW IN REGARD TO HOW FAR NORTH THAT WARM AIR WILL TRAVEL. SO...WILL MENTION FREEZING RAIN OVER THE NORTHERN COUNTIES LATE THURSDAY NIGHT WHERE TEMPS WILL HOVER AROUND THE FREEZING MARK. FORECAST SOUNDINGS ARE INDICATING WARM ENOUGH AIR FOR RAIN OVER THE REMAINDER OF THE FORECAST AREA THOUGH. PRECIP CHANCES WILL INCREASE FURTHER ON FRIDAY AS AN UPPER LEVEL LOW MOVES THROUGH THE MISSOURI VALLEY AND COMBINES WITH SURFACE FRONTAL BOUNDARY EXTENDING FROM THE DEEP SOUTH TO THE OHIO VALLEY. THESE DYNAMICS SUPPORT POPS NEAR 100 PERCENT ON FRIDAY AND FRIDAY NIGHT. AS LIFT WEAKENS ON SATURDAY...RAIN WILL TAPER OFF FROM WEST TO EAST ACROSS CENTRAL INDIANA. TEMPS...CENTRAL INDIANA WILL BE RIGHT ALONG FRONTAL BOUNDARY FOR DURATION OF SHORT TERM PERIOD. AGAIN...WEAK WARM ADVECTION WILL HELP KEEP HIGH TEMPS IN THE 40S...AND LOWS IN THE 30S. THIS WAS CAPTURED BEST WITH A MODEL BLEND. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ISSUED AT 230 AM EST THU DEC 4 2014 BROAD HIGH PRESSURE WILL BRING DRY COOL CONDITIONS ON SUNDAY IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. THE HIGH WILL SHIFT EAST QUICKLY SUNDAY NIGHT...WITH AN UPPER WAVE AND ASSOCIATED LOW PRESSURE SYSTEM TRACKING INTO THE GREAT LAKES FROM THE NORTHERN PLAINS ON MONDAY. THE GLOBAL MODELS HAVE BEEN MORE AMPLIFIED WITH THE UPPER FLOW PATTERN...AND CONSEQUENTLY BRING THE UPPER WAVE FURTHER SOUTH INTO THE OHIO VALLEY. CONSIDERING THE RIDGING EXPECTED TO DEVELOP OVER THE INTERMOUNTAIN WEST AHEAD OF STRONG LOW PRESSURE INTO THE GULF OF ALASKA...THE MORE AMPLIFIED PATTERN ALOFT SUGGESTED BY THE GLOBALS IS MORE REALISTIC AND PREFERRED AT THIS TIME. HAVE INCREASED POPS SLIGHTLY OVER SUPERBLEND GUIDANCE FOR MONDAY AND MONDAY NIGHT AS THE UPPER WAVE PASSES THROUGH THE REGION...WITH LIGHT RAIN CHANGING TO LIGHT SNOW AS COLDER AIR ARRIVES. REMAINDER OF THE EXTENDED LOOKS QUIET AS A DRY NORTHWEST FLOW ALOFT DEVELOPS WITH HIGH PRESSURE AT THE SURFACE. GLOBAL GUIDANCE IS PREFERRED THROUGH THE END OF THE LONG TERM AS OP GFS CONTINUES TO FAVOR A MUCH FLATTER AND MORE PROGRESSIVE FLOW PATTERN ALOFT AND IS OUT OF STEP WITH MOST OF THE OTHER EXTENDED GUIDANCE. UNDERCUT SUPERBLEND FOR TEMPS THROUGHOUT...WITH HIGHS PRIMARILY RANGING FROM THE UPPER 30S TO MID 40S AND LOWS IN THE 20S TO LOWER 30S. && .AVIATION /DISCUSSION FOR 040600Z TAF ISSUANCE/... ISSUED AT 1245 AM EST THU DEC 4 2014 VFR CONDITIONS EXPECTED THROUGH THIS MORNING...DETERIORATING CONDITIONS THIS AFTERNOON AND EVENING WITH PRECIPITATION. HIGH CLOUDS CONTINUE TO INCREASE EARLY THIS MORNING AS MOISTURE ALOFT SPREADS INTO THE REGION. LIGHT WINDS WILL GRADUALLY SET UP FROM THE NORTHEAST LATE TONIGHT AS A FRONTAL BOUNDARY MOVES INTO THE TENNESSEE VALLEY. LIGHT PRECIPITATION WILL EXPAND NORTHEAST THROUGH THE LOWER OHIO VALLEY AND INTO CENTRAL INDIANA DURING THE MORNING. HI RES WRF-ARW AND NMM ALONG WITH THE HRRR ALL BRING LIGHT PRECIP INTO THE I-70 CORRIDOR BY LATE MORNING. HAVE BUMPED UP VCSH MENTION AT KBMG/HUF/KIND BETWEEN 12-14Z WITH PREVAILING LIGHT RAIN DEVELOPING AT ALL SITES BY LATE MORNING. IN ADDITION WITH COLDER NEAR SURFACE AIR PRESENT IN THE MORNING...MAY SEE A BRIEF PERIOD OF LIGHT FREEZING DRIZZLE/RAIN AT THE ONSET AT BOTH KBMG AND KHUF BEFORE WARMING ENOUGH TO SUPPORT RAIN. WILL CONTINUE TO MONITOR SURFACE TEMP TRENDS OVER THE NEXT FEW HOURS. MODEL SOUNDINGS INDICATE DRIER AIR WITHIN THE BOUNDARY LAYER WILL BE SLOW TO SHIFT NORTH WHICH MAY LIMIT PRECIP INITIALLY...BUT STRONGER SURGE OF ISENTROPIC LIFT DURING THE AFTERNOON SHOULD ALLOW LOWER MVFR CEILINGS TO EXPAND NORTH. CEILINGS WILL SETTLE BETWEEN 1500-2000FT BY THE EVENING WITH LOWER VISIBILITIES IN SCATTERED LIGHT SHOWERS AND/OR DRIZZLE. EASTERLY WINDS AT 5-10KTS ARE EXPECTED FOR MUCH OF THE DAY. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...TDUD/50 SHORT TERM...TDUD/50 LONG TERM....RYAN AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1245 AM EST THU DEC 4 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 317 PM EST WED DEC 3 2014 HIGH PRESSURE WILL BRING DRY CONDITIONS TO CENTRAL INDIANA TODAY AND TONIGHT. HOWEVER...RAIN/FREEZING RAIN WILL BE BACK IN THE FORECAST BY THURSDAY AS MOISTURE INCREASES AHEAD OF A FRONTAL BOUNDARY TO THE SOUTH. THIS SURFACE FRONTAL BOUNDARY WILL COMBINE WITH AN UPPER LEVEL TROUGH BY FRIDAY NIGHT TO PRODUCE WIDESPREAD RAIN INTO SATURDAY. AFTER THAT...A DRY PERIOD WILL RETURN FOR THE SECOND HALF OF THE WEEKEND. FURTHER OUT...A STRONG UPPER LEVEL LOW IS PROGGED TO AFFECT THE AREA ON MONDAY. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 957 PM EST WED DEC 3 2014 TEMPERATURES DROPPED QUICKLY THIS EVENING WHERE CIRRUS THINNED OUT...BUT SATELLITE SHOWS THICKER CIRRUS MOVING INTO THE AREA AT THE MOMENT. THUS DO NOT EXPECT TEMPERATURES TO FALL AS FAST...AND THEY MAY LEVEL OFF IN SOME AREAS WHERE CIRRUS IS THICKEST. THUS MADE NO CHANGES TO LOW TEMPERATURES...BUT DID ADJUST HOURLY READINGS TO REFLECT CURRENT TRENDS. ADJUSTED SKY COVER UP SOME ALSO BASED ON LATEST SATELLITE IMAGES. PRECIPITATION STILL LOOKS TO HOLD OFF UNTIL AFTER 12Z. PREVIOUS DISCUSSION FOLLOWS... CALM AND DRY CONDITIONS WILL PREVAIL TONIGHT AS HIGH PRESSURE STRENGTHENS OVER THE MIDWEST. DRIER AIR HAS BEEN STREAMING INTO THE FORECAST AREA ALL DAY FROM THE NORTHWEST...AND WILL CONTINUE TO THROUGH THE NIGHT. AS A RESULT...PARTLY CLOUDY SKIES CAN BE EXPECTED TONIGHT WITH LOWS IN THE 20S DUE TO THE RADIATIONAL COOLING. MODELS ARE IN AGREEMENT IN REGARD TO THE RADIATIONAL COOLING...SO STUCK CLOSE TO GUIDANCE. && .SHORT TERM /TOMORROW THROUGH SATURDAY/... ISSUED AT 957 PM EST WED DEC 3 2014 BASED ON LATEST MODEL DATA...TEMPERATURES IN THE SOUTHERN FORECAST AREA MAY RISE A BIT FASTER THAN THOUGHT ON THURSDAY MORNING. THUS CHANGED PRECIPITATION TYPE TO FREEZING RAIN OR RAIN FOR NOW. PREVIOUS DISCUSSION FOLLOWS... THE MAIN FOCUS OF THE SHORT TERM PERIOD WILL BE PRECIP CHANCES AND TYPES WITH FRONTAL BOUNDARY TO THE SOUTH. PRECIP WILL OVERSPREAD CENTRAL INDIANA FROM THE SOUTHWEST TO NORTHEAST STARTING TOMORROW MORNING AS ISENTROPIC LIFT STRENGTHENS OVER THE MID MISSISSIPPI VALLEY. THE MAIN CHALLENGE DURING THIS PERIOD WILL BE PRECIP TYPE. A BRIEF PERIOD OF FREEZING RAIN OVER THE SOUTHERN COUNTIES WILL BE POSSIBLE EARLY THURSDAY MORNING...BUT THIS WILL QUICKLY TRANSITION TO RAIN BY MID MORNING AS TEMPERATURES INCREASE. RAIN WILL CONTINUE THROUGH THE DAY...BUT IT WILL BECOME A LITTLE TRICKY OVERNIGHT. MODELS ARE TRENDING TOWARD SOME WEAK WARM ADVECTION FROM THE SOUTH ON THURSDAY NIGHT...BUT CONFIDENCE IS LOW IN REGARD TO HOW FAR NORTH THAT WARM AIR WILL TRAVEL. SO...WILL MENTION FREEZING RAIN OVER THE NORTHERN COUNTIES LATE THURSDAY NIGHT WHERE TEMPS WILL HOVER AROUND THE FREEZING MARK. FORECAST SOUNDINGS ARE INDICATING WARM ENOUGH AIR FOR RAIN OVER THE REMAINDER OF THE FORECAST AREA THOUGH. PRECIP CHANCES WILL INCREASE FURTHER ON FRIDAY AS AN UPPER LEVEL LOW MOVES THROUGH THE MISSOURI VALLEY AND COMBINES WITH SURFACE FRONTAL BOUNDARY EXTENDING FROM THE DEEP SOUTH TO THE OHIO VALLEY. THESE DYNAMICS SUPPORT POPS NEAR 100 PERCENT ON FRIDAY AND FRIDAY NIGHT. AS LIFT WEAKENS ON SATURDAY...RAIN WILL TAPER OFF FROM WEST TO EAST ACROSS CENTRAL INDIANA. TEMPS...CENTRAL INDIANA WILL BE RIGHT ALONG FRONTAL BOUNDARY FOR DURATION OF SHORT TERM PERIOD. AGAIN...WEAK WARM ADVECTION WILL HELP KEEP HIGH TEMPS IN THE 40S...AND LOWS IN THE 30S. THIS WAS CAPTURED BEST WITH A MODEL BLEND. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... ISSUED AT 317 PM EST WED DEC 3 2014 THE LOW PRESSURE SYSTEM THAT WILL IMPACT OUR WEATHER FRIDAY INTO SATURDAY WILL QUICKLY MOVE ON QUICKLY TO THE EAST SATURDAY NIGHT. THE NEXT SYSTEM THAT WILL AFFECT OUR WEATHER IS A STRONG UPPER TROUGH WHICH WILL MOVE ACROSS OUR REGION EARLY NEXT WEEK. THE EURO AND GEMNH MODELS HAS THIS AS A CLOSED UPPER LOW...WHILE THE GFS KEEPS IT AS A OPEN TROUGH. ALL MODELS GENERATE A LITTLE PRECIPITATION AROUND MONDAY. THUS WILL ADD A CHANCE OF RAIN MAINLY MONDAY. ON DAYS 6 AND 7 THE STRONG UPPER TROUGH WILL MOVE ON TO THE EAST COAST AS A SURFACE HIGH PRESSURE SYSTEM OVER THE NORTHERN PLAINS BUILDS INTO OUR REGION BY DAY 7. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL MOST OF THE PERIOD. BUT THEY WILL BE NEAR NORMAL SUNDAY NIGHT. MADE ONLY A FEW TWEAKS TO A MOS BLEND ON TEMPERATURES. && .AVIATION /DISCUSSION FOR 040600Z TAF ISSUANCE/... ISSUED AT 1245 AM EST THU DEC 4 2014 VFR CONDITIONS EXPECTED THROUGH THIS MORNING...DETERIORATING CONDITIONS THIS AFTERNOON AND EVENING WITH PRECIPITATION. HIGH CLOUDS CONTINUE TO INCREASE EARLY THIS MORNING AS MOISTURE ALOFT SPREADS INTO THE REGION. LIGHT WINDS WILL GRADUALLY SET UP FROM THE NORTHEAST LATE TONIGHT AS A FRONTAL BOUNDARY MOVES INTO THE TENNESSEE VALLEY. LIGHT PRECIPITATION WILL EXPAND NORTHEAST THROUGH THE LOWER OHIO VALLEY AND INTO CENTRAL INDIANA DURING THE MORNING. HI RES WRF-ARW AND NMM ALONG WITH THE HRRR ALL BRING LIGHT PRECIP INTO THE I-70 CORRIDOR BY LATE MORNING. HAVE BUMPED UP VCSH MENTION AT KBMG/HUF/KIND BETWEEN 12-14Z WITH PREVAILING LIGHT RAIN DEVELOPING AT ALL SITES BY LATE MORNING. IN ADDITION WITH COLDER NEAR SURFACE AIR PRESENT IN THE MORNING...MAY SEE A BRIEF PERIOD OF LIGHT FREEZING DRIZZLE/RAIN AT THE ONSET AT BOTH KBMG AND KHUF BEFORE WARMING ENOUGH TO SUPPORT RAIN. WILL CONTINUE TO MONITOR SURFACE TEMP TRENDS OVER THE NEXT FEW HOURS. MODEL SOUNDINGS INDICATE DRIER AIR WITHIN THE BOUNDARY LAYER WILL BE SLOW TO SHIFT NORTH WHICH MAY LIMIT PRECIP INITIALLY...BUT STRONGER SURGE OF ISENTROPIC LIFT DURING THE AFTERNOON SHOULD ALLOW LOWER MVFR CEILINGS TO EXPAND NORTH. CEILINGS WILL SETTLE BETWEEN 1500-2000FT BY THE EVENING WITH LOWER VISIBILITIES IN SCATTERED LIGHT SHOWERS AND/OR DRIZZLE. EASTERLY WINDS AT 5-10KTS ARE EXPECTED FOR MUCH OF THE DAY. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TDUD NEAR TERM...TDUD/50 SHORT TERM...TDUD/50 LONG TERM....JH AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
517 AM CST THU DEC 4 2014 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 354 AM CST THU DEC 4 2014 AN UPPER LEVEL LOW WAS CENTERED NORTH OF HUDSON BAY WITH A PROGRESSIVE TROUGH EXTENDING INTO MAINE THIS EVENING. A LARGE AREA OF SURFACE HIGH PRESSURE CENTERED ALONG AN AXIS FROM WISCONSIN TO WEST VIRGINIA COVERED MUCH OF THE EASTERN UNITED STATES. LOW LEVEL MOISTURE FLOWING NORTH FROM THE GULF OF MEXICO ON THE WEST SIDE OF THE LARGE AREA OF HIGH PRESSURE SPREAD INTO KANSAS DURING THE LATE AFTERNOON AND EVENING HOURS, AND WIDESPREAD STRATUS COVERED MUCH OF SOUTHWEST AND CENTRAL KANSAS. A WARM FRONT WAS EVIDENT AT 06Z FROM A WEAK SURFACE LOW IN SOUTHWEST TEXAS TO NEAR THE RED RIVER TO NORTHERN LOUISIANA. A MINOR UPPER LEVEL TROUGH EXTENDED FROM EASTERN SOUTH DAKOTA INTO NORTHERN KANSAS, AND VEERED LOW LEVEL WINDS ABOVE THE SURFACE WERE LIMITING THE NORTHWARD EXTENT OF THE LOW LEVEL MOISTURE. A SPLIT IN THE WESTERLIES WAS EVIDENT IN THE EASTERN PACIFIC WITH A RIDGE EXTENDING FROM THE BRITISH COLUMBIA COAST INTO ALASKA AND AND AN ACTIVE SOUTHERN BRANCH JET FROM NEAR 170W THROUGH A MEAN TROUGH AROUND 125W TO THE CENTRAL PLAINS. A VIGOROUS UPPER LEVEL TROUGH WAS EVIDENT IN SATELLITE IMAGERY NEAR 120W. AN UPPER LEVEL LOW WAS CENTERED WEST OF THE OREGON COAST WITH SEVERAL MINOR TROUGHS ROTATING THROUGH THE PACIFIC NORTHWEST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 354 AM CST THU DEC 4 2014 THE MOST SIGNIFICANT SHORT TERM CHALLENGES ARE !)ANTICIPATING THE EXTENT OF FOG/FREEZING FOG EARLY THIS MORNING; 2) ANTICIPATING COVERAGE OF RAINFALL THURSDAY NIGHT INTO EARLY FRIDAY; AND 3) EVALUATING THE POSSIBILITY OF FOG FORMATION AGAIN FRIDAY MORNING AS CLOUD COVER DECREASES AFTER THE RAIN WINDS DOWN. THE DEEP UPPER LEVEL TROUGH MOVING THROUGH EASTERN CANADA WILL CONTINUE TO PROPAGATE TOWARD GREENLAND, AND THE SURFACE HIGH CENTERED IN THE UPPER MIDWEST WILL MOVE INTO NEW ENGLAND BY FRIDAY MORNING. AN UPPER LEVEL RIDGE FROM BRITISH COLUMBIA COAST TO ALASKA WILL MOVE LITTLE THROUGH THE WEEKEND. UPPER LEVEL TROUGHS EMBEDDED IN THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO MOVE ACROSS THE SOUTHWESTERN UNITED STATES TOWARD THE CENTRAL PLAINS UNTIL RIDGING AMPLIFIES IN THE WESTERN UNITED STATES AS A PROGRESSIVE LONG WAVE TROUGH DEEPENS IN THE GULF OF ALASKA EARLY NEXT WEEK. A MADDEN JULIAN OSCILLATION CENTERED NEAR THE MARITIME CONTINENT WILL CONTINUE TO MOVE EAST INTO THE WESTERN HEMISPHERE THROUGH MID DECEMBER, AND A LONG WAVE TROUGH LIKELY WILL PROPAGATE INTO THE CENTRAL PART OF THE COUNTRY AS THE MADDEN JULIAN OSCILLATION APPROACHES THE MID PACIFIC. AN EXTENDED PERIOD OF RELATIVELY MILD WEATHER IS LIKELY IN THE CENTRAL PART OF THE COUNTRY AT LEAST THROUGH 12-13 DECEMBER. LOW LEVEL MOISTURE ADVECTING INTO THE CENTRAL PART OF THE COUNTRY ON THE WEST SIDE OF THE AREA OF HIGH PRESSURE CENTERED IN THE UPPER MIDWEST IS BEING LIFTED OVER A WARM FRONT NEAR THE RED RIVER, AND WIDESPREAD STRATUS MOVED INTO KANSAS WEDNESDAY EVENING. RADIATIONAL COOLING ON THE WESTERN EDGE OF THE STRATUS DECK ALLOWED SURFACE TEMPERATURES TO FALL INTO THE UPPER 20S IN FAR WESTERN KANSAS, AND ADVECTION OF AIR WITH DEWPOINTS IN THE LOWER 30S OVER THE COLD GROUND HAS RESULTED IN FORMATION OF AREAS OF FOG. WITH CONTINUED MOIST ADVECTION INTO FAR WESTERN KANSAS, LOCALLY DENSE FOG IS LIKELY TO FORM AROUND SUNRISE AND TO PERSIST THROUGH AT LEAST MID MORNING. THE STRONG SOUTHERN BRANCH UPPER LEVEL TROUGH NEAR 120W WILL MOVE INTO WESTERN KANSAS TONIGHT. UPWARD VERTICAL MOTION IN ADVANCE OF THE UPPER LEVEL TROUGH ALONG WITH ISENTROPIC LIFTING OVER THE SHALLOW COOL AIR MASS IN KANSAS WILL SUPPORT DEVELOPMENT LIGHT RAIN IN FAR SOUTHWEST KANSAS LATE THIS AFTERNOON. THE AREA OF RAIN WILL BECOME WIDESPREAD TONIGHT AND WIND DOWN FRIDAY MORNING AS THE UPPER LEVEL TROUGH MOVES INTO CENTRAL KANSAS AND SUBSIDENCE BEGINS BEHIND THE TROUGH. A SURFACE CYCLONE WILL MOVE ALONG THE BAROCLINIC ZONE EXTENDING ACROSS OKLAHOMA INTO MISSOURI AS THE UPPER LEVEL TROUGH MOVES EAST, AND LOW LEVEL WINDS WILL BECOME NORTH BY FRIDAY MORNING. TEMPERATURES BEHIND THE WIND SHIFT FRIDAY WILL BE HIGHER THAN VALUES OBSERVED TODAY SINCE THE NORTH WINDS WILL ADVECT AIR WARMED BY DOWNSLOPE IN THE NORTHERN ROCKIES INTO WESTERN KANSAS. TEMPERATURES TODAY WILL BE HIGHLY DEPENDENT OF CLOUD COVER. HIGHS WILL BE RESTRICTED TO THE MID 40S IN AREAS WHERE THE STRATUS IS MOST PERSISTENT BUT LIKELY WILL RISE INTO THE MID 50S NEAR THE COLORADO BORDER. CLOUDINESS WILL INCREASE BY EARLY AFTERNOON AS MOISTURE IN ADVANCE OF THE UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS. TEMPERATURES TONIGHT SHOULD BE RELATIVELY MILD WITH CLOUDY SKIES AND WIDESPREAD WARM RAIN. AREAS OF FOG MAY FORM AGAIN FRIDAY MORNING NEAR THE WEST EDGE OF THE RAIN SHIELD WHERE CLOUDINESS WILL DECREASE AROUND SUNRISE. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 302 AM CST THU DEC 4 2014 PRECIPITATION CHANCES WILL CONTINUE TO TAPER OFF FROM WEST TO EAST EARLY FRIDAY AS AN UPPER LEVEL TROUGH CROSSES THE CENTRAL PLAINS. A SURFACE BOUNDARY WILL ALSO SLIDE EAST ACROSS WESTERN KANSAS EARLY IN THE DAY AND DOWNSLOPE FLOW WILL BE IMPROVING DURING THE DAY. GIVEN THE WARMING FORECAST IN THE 900 TO 800MB LEVEL THE PREVIOUS SHIFT STILL LOOKS ON TRACK WITH HIGHS CLIMBING INTO THE 50S FRIDAY AFTERNOON. DEPENDING ON AMOUNT OF SUN DEVELOPING ACROSS FAR WESTERN KANSAS HIGHS AROUND 60 ARE NOT OUT OF THE QUESTION. ON SATURDAY AN UPPER LEVEL RIDGE AXIS WILL SLIDE EAST ACROSS ACROSS THE CENTRAL AND NORTHERN PLAINS AS AN UPPER LEVEL TROUGH APPROACHES THE SOUTHERN AND CENTRAL ROCKIES. THIS NEXT UPPER LEVEL SYSTEM IS CURRENTLY EXPECTED TO CROSS THE CENTRAL HIGH PLAINS ON SATURDAY NIGHT INTO EARLY SUNDAY WITH THE GFS HINTING AT SOME PRECIPITATION DEVELOPING AS THIS SYSTEM CROSSES WESTERN KANSAS. ECMWF IS LESS EXCITED WITH THE PRECIPITATION CHANCES AND GIVEN MAINLY MID LEVEL MOISTURE WILL BE PRESENT AHEAD OF THIS SYSTEM SO AT THIS TIME WILL LEAN TOWARDS MORE CLOUDS THAN PRECIPITATION. MODELS THIS MORNING DIFFERING ON AN UPPER LEVEL SYSTEM AS IT CROSSES THE NORTHERN PLAINS SUNDAY NIGHT AND MONDAY AND HOW MUCH COOLING THAT WILL OCCUR BEHIND A COLD FRONT CROSSING THE CENTRAL PLAINS EARLY NEXT WEEK. AT THIS TIME GIVEN THAT THIS SYSTEM WAS LOCATED OUT NEAR 45N 150W CONFIDENCE IS NOT HIGH ON HOW THIS UPPER WAVE WILL EVOLVE AS IT CROSSES THE NORTHWEST UNITED STATES. HOW MUCH THE DOWNSLOPE FLOW WILL IMPACT THE COOLING BEHIND THE FRONT IS ALSO WILL THEREFORE STAY CLOSE TO WHAT THE LATEST CREXTENDEDFCST_INIT HAS GOING FOR TEMPERATURES AND PRECIPITATION CHANCES MONDAY AND TUESDAY. ANOTHER UPPER LEVEL SYSTEM WILL APPROACH THE WEST COAST MID TO LATE WEEK AND RIDGING ALOFT ALONG WITH IMPROVING WESTERLY DOWNSLOPE FLOW WILL DEVELOP ACROSS THE CENTRAL HIGH PLAINS. THIS SUPPORTS THE PREVIOUS FORECAST WITH A GRADUALLY WARMING TREND MID TO LATE WEEK WITH TEMPERATURES WARMING THROUGH THE 50S AND EVEN SOME LOW TO MID 60S BEING POSSIBLE BY THE END OF THE WORK WEEK IF THE 850MB TEMPERATURE TREND FROM THE GFS VERIFIES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 514 AM CST THU DEC 4 2014 IFR AND MVFR CEILINGS IN SOUTHWEST KANSAS WILL BE SLOW TO IMPROVE TODAY GIVEN THE THICKNESS OF THE LOW LEVEL MOISTURE FROM THE BUFR SOUNDINGS AND THE MID AND HIGH LEVEL CLOUD COVER PRECEDING AND UPPER LEVEL TROUGH WHICH WILL BE MOVING ACROSS THE SOUTHWEST UNITED STATES. USING NAM BUFR SOUNDINGS ALONG WITH THE RAP AND HRRR AS A GUIDE THE CEILINGS WILL SLOWLY IMPROVE INTO THE MVFR CATEGORY BETWEEN 15Z AND 18Z AT GCK AND DDC. VFR CONDITIONS WILL THEN DEVELOP AT GCK BETWEEN 18Z AND 21Z WHILE DDC IS FORECAST TO REMAIN IN THE MVFR CATEGORY THROUGH 00Z FRIDAY. AFTER 00Z FRIDAY CEILINGS ARE EXPECTED TO LOWER BACK INTO THE IFR CATEGORY WITH LIGHT RAIN AND FOG DEVELOPING. LIGHT RAIN IS EXPECTED TO DEVELOP AT DDC AND GCK BY 03Z FRIDAY. PRECIPITATION WILL BEGIN TO MOVE INTO HYS TOWARDS 06Z. SOUTHERLY WINDS WILL BE AT 10 KNOTS OR LESS TODAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 49 39 55 28 / 20 80 20 0 GCK 50 36 57 27 / 20 80 0 0 EHA 54 37 59 30 / 50 70 0 0 LBL 50 39 59 29 / 50 80 0 0 HYS 50 37 54 26 / 0 70 30 0 P28 49 44 54 32 / 30 90 50 0 && .DDC WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR KSZ061-062-074-075-084-085. && $$ SYNOPSIS...RUTHI SHORT TERM...RUTHI LONG TERM...BURGERT AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1043 PM MST WED DEC 3 2014 .UPDATE... ISSUED AT 550 PM MST WED DEC 3 2014 LARGE AREA OF STRATUS IS MOVING IN FROM SOUTH CENTRAL AND SOUTHWEST KANSAS. MODELS DIFFER A LITTLE ON FAR NORTH AND WEST TO TAKE THE HIGHER LOW LEVEL MOISTURE. RIGHT NOW IT LOOKS LIKE THE RAP AND HRRR IS CATCHING THIS THE BEST. SO INCREASED CLOUD COVER TO ACCOUNT FOR THIS FOR TONIGHT INTO TOMORROW MORNING. MODELS ALSO DIFFER ON IF OR HOW MUCH FOG THERE WILL BE. THE NAM KEEPS IT SOUTH OF MY AREA. HOWEVER...THE RAP AND ESPECIALLY THE HRRR BRING AN AREA OF FOG...MAINLY ALONG AND EAST OF THE COLORADO BORDER. THIS IS FURTHER WEST THAN WHAT WAS EARLIER EXPECTED. ALSO THE HRRR WOULD SUPPORT SOME DENSE FOG. AM NOT TOTALLY CONVINCED ABOUT THIS. THE DEWPOINTS ARE STILL RATHER LOW SOUTH OF US AND WILL NEED TO CLIMB A LOT TO REACH SATURATION. SO AT THIS TIME ONLY INSERTED PATCHY FOG AND WILL CONTINUE TO MONITOR MODEL/OBSERVATION TRENDS. ANOTHER UPDATE MAY BE NEEDED. RAISED MINS A LITTLE...MAINLY THE SOUTHERN PORTION...WHERE THE CLOUD COVER COMES IN THE EARLIEST. DEPENDING ON HOW FAST THIS MOVES IN...I MAY NEED TO RAISE THE TEMPERATURES MORE. && .SHORT TERM...(TONIGHT THROUGH THURSDAY) ISSUED AT 1252 PM MST WED DEC 3 2014 UPPER FLOW WILL BE ZONAL THROUGH THURSDAY. A SURFACE HIGH WILL DRIFT EAST THURSDAY WITH A TROUGH IN EASTERN COLORADO. POPS WILL BE NIL TONIGHT AND THURSDAY DUE TO SUBSIDENCE. SOUTH WIND WILL BECOME LIGHT AND VARIABLE THURSDAY. SOUTH WINDS WILL ADVECT IN HIGHER BOUNDARY LAYER RELATIVE HUMIDITY INTO THE SOUTHERN FA FROM AROUND 09Z TO 15Z. PLAN TO INSERT SOME PATCHY FOG INTO THE FORECAST FOR THAT AREA OVERNIGHT AND THURSDAY MORNING. 850MB TEMPERATURES RISE TO AROUND 10C IN THE WESTERN FA ON THURSDAY. WITH LOTS OF SUN, MAX TEMPERATURES SHOULD REACH THE MID 50S IN THE WESTERN FA AND AROUND 50 IN THE EASTERN FA. MIN TEMPERATURES SHOULD COOL TO AROUND 20 TONIGHT. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 1252 PM MST WED DEC 3 2014 MODELS A LITTLE MORE ROBUST WITH SHORTWAVE TROUGH COMING OUT OF THE FOUR CORNERS REGION THURSDAY NIGHT AND ASSOCIATED LIGHT PRECIPITATION SHIELD. TEMPERATURE PROFILES SHOW IT WILL BE ALL RAIN. SURFACE WET BULB TEMPERATURES WILL REMAIN IN THE UPPER 30S TO LOWER 40S ACROSS NORTHWEST KANSAS WHICH SHOULD BE WARM ENOUGH TO EXCLUDE THE POSSIBILITY OF FREEZING PRECIPITATION. BUMPED UP POPS AND OVERNIGHT LOW TEMPERATURES...BOTH COULD BE NUDGED UP A LITTLE MORE IF TRENDS CONTINUE. QPF WILL BE LESS THAN A TENTH OF AN INCH. PRECIPITATION SHOULD BE DONE BY EARLY FRIDAY MORNING AS THE SYSTEM QUICKLY MOVES EAST. SHORTWAVE RIDGING WILL MOVE ACROSS THE REGION FRIDAY AND SATURDAY WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES. A COUPLE OF DISTURBANCES COME OUT OF THE ROCKIES SATURDAY NIGHT AND SUNDAY. MODELS REMAIN DRY AT THIS POINT BUT CAN NOT TOTAL RULE OUT SOME LIGHT RAIN OR SPRINKLES. THE FIRST HALF OF NEXT WEEK WILL FEATURE A LARGE RIDGE BUILDING OVER THE GREAT BASIN AND GRADUALLY SPREADING EASTWARD TOWARDS THE ROCKIES. MODELS HINT AT ANOTHER POSSIBLE WEAK SYSTEM COMING OVER THE RIDGE AROUND MID WEEK BUT MOISTURE WILL BE SPARSE AND PRECIPITATION CHANCES SLIM. THERE IS NO COLD AIR IN SIGHT WITH TEMPERATURES REMAINING SLIGHTLY ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1038 PM MST WED DEC 3 2014 LATEST MESOSCALE MODEL GUIDANCE HAS BACKED OFF ON STRATUS AND ESPECIALLY FOG COVERAGE. TEMPERATURE AND DEWPOINT SPREADS REMAIN RATHER HIGH TO OUR SOUTH. WITH NO SIGNIFICANT LOW LEVEL MOISTURE ADVECTION EXPECTED AND THICK MID/UPPER LEVEL CLOUD COVER...IT LOOKS LIKE THE MVFR CONDITIONS WILL STAY SOUTH AND EAST OF BOTH TAF SITES. DID INCLUDE A SCATTERED LOW CLOUD DECK AT KGLD UNTIL 12Z. SOME PRECIPITATION IS EXPECTED TO DEVELOP THURSDAY NIGHT BUT LOOKS TO STILL BE SOUTH OF THE PERIOD BY THE END OF THIS PERIOD. OTHERWISE WINDS WILL BE LIGHT AND SHIFTING THROUGH THE PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...FS LONG TERM...024 AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
856 PM CST FRI DEC 5 2014 .DISCUSSION... FRONTAL BOUNDARY AS OF 8 PM WAS ORIENTED NEAR A FYV...FSM... PRX...SEP LINE MOVING SLOWLY SOUTH AND EAST. A NARROW LINE OF MOSTLY SHOWERS HAD DEVELOPED ALONG AND JUST AHEAD OF THIS BOUNDARY ACROSS PORTIONS OF CENTRAL/SW AR INTO EXTREME SE OK AND PORTIONS OF NE TX. THIS LINE LOOKED A LITTLE BETTER A COUPLE OF HOURS AGO BUT WITH THE LOSS OF DAYTIME HEATING AND INSTABILITY LOOKING VERY WEAK...NOT EXPECTING MUCH IN THE OF CONVECTION BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE THROUGHOUT THE NIGHT. FRONT IS EXPECTED TO BE NEAR THE I-30 CORRIDOR BY MIDNIGHT AND JUST EAST OF A LFK...SHV...ELD LINE BY 12Z IN THE MORNING. FOR THE UPDATE...HAVE ORIENTED POPS HIGHEST ACROSS OUR EASTERN MOST ZONES FOR THE REMAINDER OF THE NIGHT. THIS IS IN GOOD OVERALL AGREEMENT WITH THE HRRR AND THE 00Z NAM OUTPUT WHICH PUTS THE BEST QPF PROBABILITIES WHERE THE HIGHER MOISTURE CONTENT RESIDES. ALSO ADDED THE LIKELIHOOD OF PATCHY DENSE FOG ACROSS ALL BUT OUR EXTREME NW ZONES. TEMP/DEWPOINT DEPRESSIONS ARE VERY LOW ATTM AND WITH THE VERY MOIST LOW LEVEL ATMOSPHERE PRESENT...UNTIL THE FRONT COMES THROUGH...FOG IS A PRETTY GOOD BET OVERNIGHT. NO ADDITIONAL CHANGES WERE NECESSARY THIS EVENING...UPDATE OUT SHORTLY...13. && .PREV DISCUSSION... /ISSUED 611 PM CST FRI DEC 5 2014/ AVIATION... FOR THE 06/00Z TAFS...A FEW SHWRS CONTINUE TO AFFECT MLU EARLY THIS EVENING BUT WILL SLOWLY TAPER OFF WITHIN THE NEXT FEW HOURS. MEANWHILE...A COLD FRONT IS BEGINNING TO ENTER THE FAR NW EDGE OF OUR REGION WITH A THIN LINE OF SHWRS ALONG THE BNDRY. THIS FRONT WILL CONTINUE TO MOVE ACROSS THE REGION OVERNIGHT INTO SATURDAY MORNING WITH MVFR/IFR CIGS AND VSBYS ALONG WITH SHWRS NEAR FROPA. LOW CIGS WILL LINGER THROUGH AT LEAST LATE MORNING AND POSSIBLY EARLY AFTERNOON ON SATURDAY. LIGHT SOUTH WINDS AHEAD OF THE FRONT WILL QUICKLY SHIFT N/NW BEHIND THE FRONT WITH SPEEDS NEAR 10 KTS. /19/ .PRELIMINARY POINT TEMPS/POPS... SHV 62 68 43 54 42 / 40 0 0 10 10 MLU 62 68 42 55 41 / 50 10 0 10 10 DEQ 52 61 39 49 38 / 10 0 0 10 10 TXK 55 64 41 51 39 / 30 0 0 10 10 ELD 58 68 41 51 39 / 50 0 0 10 10 TYR 55 66 45 55 42 / 20 0 0 20 20 GGG 57 68 43 54 42 / 20 0 0 10 10 LFK 62 71 48 57 46 / 20 10 10 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 19/13
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
253 PM EST THU DEC 4 2014 .SYNOPSIS... HIGH PRESSURE LINGERS ALONG THE NORTHEASTERN SEABOARD THROUGH FRIDAY. LOW PRESSURE DRIFTS EAST ACROSS FROM THE MID-SOUTH STATES FRIDAY NIGHT AND ACROSS THE MID- ATLANTIC SATURDAY. MORE HIGH PRESSURE IS EXPECTED NORTH OF THE AREA EARLY NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY NIGHT/... THE LEADING OF A REGIONAL-SCALE BATCH OF RAIN NOW SLIDING INTO THE WINDWARD SIDES OF THE SRN/CNTRL APLCNS. HIGH PRESSURE TO OUR NORTH WILL ACTUALLY STRENGTHEN AS IT MOVES EAST...FROM THE GREAT LAKES TO NEW ENGLAND THIS EVE INTO EARLY FRI. THIS FEATURE WILL HELP TO USHER-IN ANOTHER WEAK CAD SITUATION W/ INCOMING OVERRUNNING PRECIP FROM THE WEST. THE PRECIP HOWEVER IS NOT ASSOCIATED W/ A LOW PRESSURE SYSTEM...MERELY A MINOR UPPER WAVE CAUGHT IN THE ZONAL UPPER PATTERN. THE MOISTURE LARGELY WAS DRAWN FROM THE GULF COAST REGION AND WILL WANE IN THE COMING HRS AS THE FORCING WEAKENS. TEMPS WILL HOVER IN THE 40S FOR MUCH OF THE AREA AND ONLY DROPPING TO THE U30S EVEN ACROSS THE HIGHER TERRAIN AS RAIN APPROACHES AND AFFECTS THE WRN HALF OF THE AREA. LATEST RUNS OF THE HRRR BRING IN SEVERAL WAVES OF LIGHT RAIN OVER THE WRN ZONES OF THE APLCNS BUT DISSIPATE MUCH OF THE ACTIVITY THAT ATTEMPTS TO REACH OR CROSS THE NRN VA BLUE RIDGE. EVEN THOUGH YESTERDAY WAS A FAIRLY HUMID DAY IN TERMS OF LOW LEVEL MOISTURE...A LARGE REGION OF DRY AIR IS MOVING OVERHEAD - AS INDICATED BY THE 12Z KIAD SOUNDING. BELOW 850MB... SUBSTANTIALLY LESS DRY BUT CONSIDERING THE INCOMING CIG HEIGHTS ARE MOSTLY ABOVE 10KFT...IT WILL TAKE A WHILE FOR THE BOUNDARY LAYER TO SATURATE AND FOR PRECIP TO REACH THE SFC. BECAUSE OF THE RELATIVE WEAKNESS OF THE INCOMING WAVE...NOT ANTICIPATING A GOOD COLD AIR SURGE FROM THE NORTH. A MORE POTENT LOW PRES SYSTEM WILL BE GEARING UP EVEN FURTHER BACK TO OUR WEST TONIGHT INTO TMRW...BUT NOT CLOSE ENOUGH TO MAXIMIZE THE CAD ABILITIES OF THE NEW ENGLAND 1040MB HIGH. SOME IN-SITU DAMMING WILL BEGIN LATER TONIGHT THAT WILL ALLOW TEMPS TO DECREASE TOWARD THE FREEZING MARK BUT NOT QUITE GET THERE FOR MUCH OF THE AREA BY EARLY FRI MRNG. LOOKING THRU AREA FORECAST SOUNDINGS USING 12Z GUIDANCE...NAM/GFS BOTH INDICATE THE WARM NOSE FAIRLY ELEVATED - IN THE 5-8KFT RANGE AND ALSO A POCKET OF DRIER AIR BELOW THE INVERSION THAT HANGS-IN THRU MID MRNG MON. LOW CONFIDENCE IN THE FREEZING RAIN POTENTIAL FOR SPECIFIC LOCATIONS AND TIMING. NO HEADLINES FOR THIS UPCOMING FORECAST UPDATE...W/ AN EMPHASIS ON A LIGHT WINTRY MIX FOR THE HIGHER TERRAIN INTO THE OVERNIGHT HRS. HEADING INTO THE PREDAWN HRS...ONLY POCKETS OF FZRA ARE EXPECTED AND MAINLY IN A SHALLOW LAYER FOR SPECIFIED HIGHER RIDGELINES IN THE POTOMAC HIGHLANDS AND POSSIBLY SOME SHELTERED VLYS W/ COLD AIR TRAPPING. MAY HAVE SUPER-COOLED RAIN IN THE ABSENCE OF A STRONGER COLD/DRY PUSH FROM THE NORTH. THE INCOMING PRECIP ALSO LOOKS TO BE VERY LIGHT AND INTERMITTENT AS THE FORCING FOR THE PRECIP TAPERS OFF INTO THE EARLY MRNG HRS. WILL MONITOR THE INCOMING PRECIP...TEMP TRENDS...AND NEWER GUIDANCE FOR POTENTIAL WINTER HEADLINES. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... WV OF LOPRES IN THE MID OHVLY SAT MRNG WL MARCH ACRS THE CWFA DURING THE DAY. ECMWF TRENDING SLOWER/FURTHER S THAN CONSENSUS. WL NOT BE JUMPING ON BOARD YET. INSTEAD...KEEPING FCST MID-PACK. REGARDLESS... SAT LOOKING LIKE A WET DAY FOR AREA AS 40 KT H8 FLOW AHD OF LOW WL SUPPLY NOT ONLY MSTR BUT THTE RDG/UPGLIDE TO WRING IT OUT. CAT POPS AREAWIDE...SPCLY E WHERE LLJ RESIDES. CFP SAT LT AFTN-EVE. DRY AIR CRASHES IN BEHIND...WHICH MEANS WL ALSO HV SOME GUSTY WINDS. UPSLP POTL DOESNT LOOK THAT GREAT EITHER. CAN SEE CLDS BANKING UP AGAINST THE WRN SLOPES...BUT COLUMN TOO DRY/INVSN COMES TOO QUICK FOR PCPN. WL KEEP 20-25 KT GUSTS SAT NGT...AND KEEP IT BREEZY INTO SUN. HIPRES WL BLD SUN. ECMWF ONCE AGN SLOWER THAN GFS IN CLRG. COMPROMISED A LTL DURING THE MRNG...OTRW WL HV A MOSUN-SUNNY DAY. DUE TO TRACK OF LOW...DONT THINK WE/LL HV A CAD WEDGE TO DEAL WITH...AND RAISED MAXT SAT INTO LWR 50S. STILL WONT BE A PLEASANT DAY...JUST NOT AS COOL/RAW. LTLCG NCSRY SAT NGT-SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... DRY...COLDER AIRMASS WILL BUILD OVER THE MID ATLANTIC REGION SUNDAY NIGHT. ON MONDAY THERE IS A SLIGHT CHANCE OF LIGHT RAIN RETURNING AS THE SURFACE LOW STARTS MOVING TOWARD EASTERN CANADA. CHANCE OF PRECIPITATION WILL INCREASE MONDAY NIGHT THHROUGH TUESDAY WHEN AN STRONG SHORTWAVE CROSSES THE AREA. MAY BE ENOUGH COLD AIR IN PLACE TO SUPPORT SCATTERED LIGHT WINTRY MIX WEST OF THE BLUE RIDGE MONDAY NIGHT INTO TUESDAY MORNING. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... DENSE HIGH CLOUDS NOW OVERHEAD AND WILL CONTINUE TO BUILD FOR THE COMING HRS THIS EVE. A FEW BATCHES OF RAIN WILL WORK THEIR WAY OVER THE APLCNS AND TOWARD THE WRN DC SUBURBS BUT LARGELY DISSIPATE BEFORE REACHING THE BLUE RIDGE. CIGS WILL CONTINUE TO DROP OVER THE COURSE OF THE EVE/NIGHTTIME HRS BUT STAY W/IN VFR RANGES TO HIGH-END MVFR BRIEFLY DURING THE PREDAWN FRI MRNG. HIGH PRESSURE MOVING NORTH OF THE AREA WILL TURN SFC FLOW TO A MORE ELY DIRECTION THRU THE NEXT SEVERAL HRS AND ESPEC INTO FRI MRNG. TEMPS WILL DROP BACK DOWN INTO THE MIDDLE 30S FOR MOST AREAS OVERNIGHT AND ROUGHLY THE SAME CONDITIONS FOR FRI AFTN W/ MORE RAIN SHOWERS MOVING IN FROM THE WEST. OUTLOOK... SAT...MVFR-IFR CONDS LKLY AS LOPRES TRACKS OVER TERMINALS. SUN-MON...VFR TUE...MVFR PSBL. && .MARINE... A STRENGTHENING HIGH WELL TO OUR NORTH HAS DROPPED OFF WINDS TO A LIGHT/VRB REGIME THIS AFTN AND WILL SWITCH THEM TO ELY OVERNIGHT INTO FRI. SCA CONDITIONS NOT ANTICIPATED INTO FRI...W/ MORE RAIN ARRIVING BY FRI AFTN/EVE. SLY WINDS SAT AS LOPRES PASSES NEWD JUST W OF WATERS. WNDS WUD BE GRADIENT DRIVEN. ATTM...THAT LOOKS TO BE BELOW SCA THRESHOLDS. HWVR...THE GRADIENT WUD BE INCRSG SAT NGT IN THE WAKE OF THE LOW W/ A BETTER MIXED PROFILE AS WELL. SCA CONDS SEEMS LKLY SAT NGT...CONTG INTO SUN. HV KEPT GRIDS BELOW GLW CRITERIA. GFS SUGGESTING OTRW. WINDS WL BE RELAXING THRU SUN AFTN-EVE AS HIPRES BLDS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HTS NEAR TERM...GMS SHORT TERM...HTS LONG TERM...CEM AVIATION...GMS/HTS MARINE...GMS/HTS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
310 AM EST THU DEC 4 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 338 PM EST WED DEC 3 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF CENTERED FM HUDSON BAY INTO THE GREAT LKS DOWNSTREAM OF A RDG OVER WRN CANADA. SHRTWV EMBEDDED WITHIN THE NW FLOW ALF IS TRACKING THRU ONTARIO AND DRAGGING A COLD FNT THRU THE UPR LKS. WNW FLOW OF COLDER AIR...WITH 12Z H85 TEMPS DOWN TO -17C AT INL...IN THE WAKE OF THIS FROPA IS CAUSING SOME LES IN THE FAVORED SN BELTS. ALTHOUGH SOME MDT SN SHOWERS IMPACTED THE FAVORED SN BELTS OVER THE W EARLIER THIS AFTN WITH 3-6 INCHES OF SN FALLING JUST W OF BARAGA...DNVA/DEEP LYR QVECTOR DVGC...SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE AND THE ADVECTION OF DRY NEAR SFC AIR UPSTREAM IN NRN MN IS LIMITING THE INTENSITY OF THE SN SHOWERS THERE NOW. THE MORE NMRS MULTIPLE BAND SN SHOWERS ARE NOW STREAMING INTO THE ERN CWA. EVEN WHERE THE SN SHOWERS ARE NOT PARTICULARLY HEAVY...GUSTY WINDS THAT REACHED AS HI AS 45-50 MPH/BLSN ARE RESULTING IN REDUCED VSBYS. LOOKING FARTHER TO THE W...THERE IS A SFC HI PRES RDG OVER THE PLAINS...AND PWAT AS LO AS 0.11 INCH AT ABERDEEN SDAKOTA /ABOUT 50 PCT OF NORMAL/. DESPITE THIS DRYNESS...THERE ARE SOME HI CLDS MOVING THRU THE NRN PLAINS. MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES AND WIND TRENDS/TOTALS AS WELL AS MIN TEMPS TNGT. LATE TODAY/TNGT...PERSISTENT DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE CONTRIBUTING TO 12HR H5 HGT RISES FCST IN EXCESS OF 150M BTWN 18Z TODAY AND 06Z TNGT/LOWERING INVRN BASE TO H9-850 AS WELL AS THE ADVECTION OF DRIER AIR WL TEND TO LIMIT LES INTENSITY. THERE COULD BE A PERIOD OF MODERATE SN SHOWERS E OF MUNISING INTO THE EVNG BEFORE THE DRIER LLVL AIR ARRIVES THERE. CONSIDERED AN LES ADVY FOR THIS AREA WITH THE GUSTY WINDS/BLSN AND FAVORABLE FCST UVV WITHIN THE DGZ BTWN ABOUT 2-5K FT...BUT NEGATIVE DYNAMICS/DRY ADVECTION NOTED EARLIER AS WELL AS EXPECTED SHIFTING WINDS ASSOCIATED WITH APRCHG SFC HI PRES FM THE PLAINS THAT WL LIMIT RESIDENCE TIME OF THE BANDS INDICATES ADVY SN TOTALS WL NOT BE WIDESPREAD ENUF TO JUSTIFY THE HEADLINE. ISSUED A SPECIAL WX STATEMENT FOR ALGER/LUCE COUNTIES TO DISCUSS THE LES/BLSN/POTENTIAL FOR MINOR LK SHORE EROSION AND FLOODING ACCOMPANYING THE LARGE WAVES FCST TO BUILD AS HI AS 13-15FT THIS EVNG. CLOSER APRCH OF SFC HI PRES WITH BACKING/DIMINISHING WINDS TOWARD THE SW LATE WL END ANY LINGERING LES OVER THE FAR W. ALTHOUGH SOME HI CLDS MAY DRIFT E FM THE NRN PLAINS INTO THIS AREA LATE...LIGHTER WINDS/DRY AIR WL ALLOW TEMPS TO FALL BLO ZERO NEAR THE WI BORDER. THU...AS THE UPR FLOW TENDS MORE ZONAL...SFC HI PRES IS FCST TO SHIFT E TOWARD NEW ENGLAND. THE UPR LKS WL BE DOMINATED BY RETURN SSW FLOW BTWN THIS DEPARTING SFC HI AND FALLING MSLP IN THE PLAINS. SOME OF THE MODELS...MAINLY THE 12Z GLOBAL AND REGIONAL CNDN MODELS...GENERATE SOME LGT PCPN UNDER LARGER SCALE ISENTROPIC ASCENT. BUT SINCE STRONGER DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THIS WAA AND SOME DVPA IN ADVANCE OF A WEAK SHRTWV MOVING THRU ONTARIO WL PASS TO THE N...THERE WL BE A CONTINUED FEED OF LLVL DRY AIR AND THE LLVL FLOW WL REMAIN WEAKLY ACYC...WL TEND TOWARD THE DRIER FCSTS. CONCERNED SOME LES COULD DVLP OFF LK MI DURING THE AFTN WHEN A STRONGER SSW FLOW DVLPS THERE...BUT NAM FCST SDNGS SHOW LO INVRN BASE NEAR H925 AND ENUF LLVL DRY AIR TO LIMIT THIS POTENTIAL. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 310 AM EST THU DEC 4 2014 NAM SHOWS A TROUGH OVER THE CENTRAL PLAINS WITH A RIDGE IN THE WESTERN U.S. 12Z FRI AND A TROUGH OFF THE PACIFIC COAST. THERE IS ALSO A SHORTWAVE ACROSS THE CANADIAN PRAIRIES. BOTH TROUGHS HEAD EAST FRI NIGHT. TROUGHING THEN MOVES INTO THE NORTHERN ROCKIES 12Z SUN. LOOKS DRY FOR SAT AND SAT NIGHT AND QUIET FOR THIS FORECAST PERIOD. WITH A WEAK DISTURBANCE MOVING THROUGH ON FRI...SLIGHT CHANCE POPS WITH SOME LAKE ENHANCEMENT FROM LAKE MICHIGAN OVER THE EASTERN CWA CANNOT COMPLETELY BE RULED OUT. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE PLAINS AND NORTHERN ROCKIES 12Z SUN WITH AN ALBERTA CLIPPER SYSTEM MOVING SOUTHEAST TOWARDS THE AREA. THIS TROUGH HEADS INTO THE UPPER GREAT LAKES 12Z MON. THIS TROUGH MOVES TO THE EAST WITH SFC HIGH PRESSURE MOVING INTO THE AREA 12Z TUE. THE SFC HIGH MOVES TO THE EAST 12Z WED BUT IS STILL CLOSE ENOUGH TO AFFECT THE WEATHER. TEMPERATURES LOOK TO STAY NEAR NORMAL THIS FORECAST PERIOD. WILL BRING IN SOME CHANCE POPS FOR SUNDAY NIGHT AND FOR MONDAY FOR MOST OF THE AREA WITH THE ALBERTA CLIPPER MOVING IN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1208 AM EST THU DEC 4 2014 DRY AIR MOVING IN FROM MN WILL RESULT IN DIMINISHING LES AND IMPROVING CONDITIONS AT CMX OVERNIGHT. AS THE WINDS ALSO TAPER OFF...THE BLSN WILL ALSO DIMINISH RESULTING IN VFR VSBY. HOWEVER... THE UPSLOPE FLOW...ESPECIALLY WITH A MORE FAVORABLE WRLY FETCH LATE TONIGHT INTO EARLY THU WILL KEEP CIGS NEAR MVFR THRESHOLD DESPITE THE INCOMING DRY AIR UNTIL WINDS BACKING TO SW BRING IMPROVEMENT THU MORNING. OTHERWISE...VFR CONDITIONS ARE EXPECTED AT IWD AND SAW. ALTHOUGH MID CLOUDS WILL INCREASE THU...LINGERING LOW LEVEL DRY AIR WILL RESULT IN PREDOMINANT VFR CONDITIONS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 256 PM EST WED DEC 3 2014 STRONG WINDS AND LIGHT TO MODERATE FREEZING SPRAY POSSIBLE. A EXITING LOW NEAR JAMES BAY WILL KEEP A WEAKENING TROUGH ACROSS LAKE SUPERIOR. W-NW GALES OF 35-40KTS ARE EXPECTED INTO THIS EVENING. THE TROUGH WILL BE REPLACED BY HIGH PRESSURE SYSTEM OVERNIGHT INTO THURSDAY MORNING /WITH WINDS DIMINISHING/...BEFORE IT EXITS INTO S QUEBEC LATE THURSDAY. A LOW SLIDING ACROSS S CENTRAL CANADA THURSDAY AND THURSDAY NIGHT WILL CROSS LAKE SUPERIOR ON FRIDAY. BEHIND THIS LOW...A HIGH WILL BUILD IN FROM THE N PLAINS SATURDAY. THE HIGH WILL THEN PUSH ACROSS THE LOWER GREAT LAKES SATURDAY NIGHT. A LOW PRESSURE SYSTEM MAY ORGANIZE OVER SOUTH CENTRAL CANADA AND POSSIBLY CROSS INTO THE UPPER GREAT LAKES ON SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...07 AVIATION...JLB MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1208 AM EST THU DEC 4 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 338 PM EST WED DEC 3 2014 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF CENTERED FM HUDSON BAY INTO THE GREAT LKS DOWNSTREAM OF A RDG OVER WRN CANADA. SHRTWV EMBEDDED WITHIN THE NW FLOW ALF IS TRACKING THRU ONTARIO AND DRAGGING A COLD FNT THRU THE UPR LKS. WNW FLOW OF COLDER AIR...WITH 12Z H85 TEMPS DOWN TO -17C AT INL...IN THE WAKE OF THIS FROPA IS CAUSING SOME LES IN THE FAVORED SN BELTS. ALTHOUGH SOME MDT SN SHOWERS IMPACTED THE FAVORED SN BELTS OVER THE W EARLIER THIS AFTN WITH 3-6 INCHES OF SN FALLING JUST W OF BARAGA...DNVA/DEEP LYR QVECTOR DVGC...SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE AND THE ADVECTION OF DRY NEAR SFC AIR UPSTREAM IN NRN MN IS LIMITING THE INTENSITY OF THE SN SHOWERS THERE NOW. THE MORE NMRS MULTIPLE BAND SN SHOWERS ARE NOW STREAMING INTO THE ERN CWA. EVEN WHERE THE SN SHOWERS ARE NOT PARTICULARLY HEAVY...GUSTY WINDS THAT REACHED AS HI AS 45-50 MPH/BLSN ARE RESULTING IN REDUCED VSBYS. LOOKING FARTHER TO THE W...THERE IS A SFC HI PRES RDG OVER THE PLAINS...AND PWAT AS LO AS 0.11 INCH AT ABERDEEN SDAKOTA /ABOUT 50 PCT OF NORMAL/. DESPITE THIS DRYNESS...THERE ARE SOME HI CLDS MOVING THRU THE NRN PLAINS. MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES AND WIND TRENDS/TOTALS AS WELL AS MIN TEMPS TNGT. LATE TODAY/TNGT...PERSISTENT DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE CONTRIBUTING TO 12HR H5 HGT RISES FCST IN EXCESS OF 150M BTWN 18Z TODAY AND 06Z TNGT/LOWERING INVRN BASE TO H9-850 AS WELL AS THE ADVECTION OF DRIER AIR WL TEND TO LIMIT LES INTENSITY. THERE COULD BE A PERIOD OF MODERATE SN SHOWERS E OF MUNISING INTO THE EVNG BEFORE THE DRIER LLVL AIR ARRIVES THERE. CONSIDERED AN LES ADVY FOR THIS AREA WITH THE GUSTY WINDS/BLSN AND FAVORABLE FCST UVV WITHIN THE DGZ BTWN ABOUT 2-5K FT...BUT NEGATIVE DYNAMICS/DRY ADVECTION NOTED EARLIER AS WELL AS EXPECTED SHIFTING WINDS ASSOCIATED WITH APRCHG SFC HI PRES FM THE PLAINS THAT WL LIMIT RESIDENCE TIME OF THE BANDS INDICATES ADVY SN TOTALS WL NOT BE WIDESPREAD ENUF TO JUSTIFY THE HEADLINE. ISSUED A SPECIAL WX STATEMENT FOR ALGER/LUCE COUNTIES TO DISCUSS THE LES/BLSN/POTENTIAL FOR MINOR LK SHORE EROSION AND FLOODING ACCOMPANYING THE LARGE WAVES FCST TO BUILD AS HI AS 13-15FT THIS EVNG. CLOSER APRCH OF SFC HI PRES WITH BACKING/DIMINISHING WINDS TOWARD THE SW LATE WL END ANY LINGERING LES OVER THE FAR W. ALTHOUGH SOME HI CLDS MAY DRIFT E FM THE NRN PLAINS INTO THIS AREA LATE...LIGHTER WINDS/DRY AIR WL ALLOW TEMPS TO FALL BLO ZERO NEAR THE WI BORDER. THU...AS THE UPR FLOW TENDS MORE ZONAL...SFC HI PRES IS FCST TO SHIFT E TOWARD NEW ENGLAND. THE UPR LKS WL BE DOMINATED BY RETURN SSW FLOW BTWN THIS DEPARTING SFC HI AND FALLING MSLP IN THE PLAINS. SOME OF THE MODELS...MAINLY THE 12Z GLOBAL AND REGIONAL CNDN MODELS...GENERATE SOME LGT PCPN UNDER LARGER SCALE ISENTROPIC ASCENT. BUT SINCE STRONGER DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THIS WAA AND SOME DVPA IN ADVANCE OF A WEAK SHRTWV MOVING THRU ONTARIO WL PASS TO THE N...THERE WL BE A CONTINUED FEED OF LLVL DRY AIR AND THE LLVL FLOW WL REMAIN WEAKLY ACYC...WL TEND TOWARD THE DRIER FCSTS. CONCERNED SOME LES COULD DVLP OFF LK MI DURING THE AFTN WHEN A STRONGER SSW FLOW DVLPS THERE...BUT NAM FCST SDNGS SHOW LO INVRN BASE NEAR H925 AND ENUF LLVL DRY AIR TO LIMIT THIS POTENTIAL. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 256 PM EST WED DEC 3 2014 MAY SEE SOME SNOW OVER NRN/ERN UPPER MI FRI AS A SHORTWAVE MOVES NEAR OR N OF THE CWA. 00Z/02 ECMWF SHOWS THE MOST SNOW /STILL ONLY 0.10 INCHES OF QPF OR LESS/ AS IT HAS THE SHORTWAVE FARTHEST S...WHILE OTHER MODELS BARELY HAVE ANY QPF. WILL KEEP SLIGHT CHANCE POPS OVER THE NERN CWA...LINGERING INTO FRI NIGHT OVER THE E AS COLDER AIR AND NW LOW LEVEL WINDS RESULT BEHIND THE SHORTWAVE...BUT STILL NOT SUFFICIENT FOR MORE THAN ISOLATED LES. 1038MB SFC HIGH MOVES ACROSS THE CWA ON SAT...WITH INCREASING LOW LEVEL WARMTH /850MB TEMPS INCREASING TO AROUND 2C/ IN SW FLOW BEHIND THE HIGH ON SUN. CONFIDENCE DECREASES SUN THROUGH NEXT WED AS MODELS DISAGREE SIGNIFICANTLY WITH A SHORTWAVE AND UPPER TROUGH MOVING ACROSS THE REGION. WHILE TIMING IS NOT AGREED ON...850MB TEMPS DROPPING INTO THE TEENS BELOW ZERO WILL LEAD TO LES BEHIND THE SHORTWAVE/TROUGH SOMETIME MON INTO TUE. MODELS CONTINUE TO DISAGREE SIGNIFICANTLY WITH THE PATTERN BEHIND THE TROUGH. WILL USE CONSENSUS OF GUIDANCE BLENDED WITH PREVIOUS FORECAST FOR THIS PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1208 AM EST THU DEC 4 2014 DRY AIR MOVING IN FROM MN WILL RESULT IN DIMINISHING LES AND IMPROVING CONDITIONS AT CMX OVERNIGHT. AS THE WINDS ALSO TAPER OFF...THE BLSN WILL ALSO DIMINISH RESULTING IN VFR VSBY. HOWEVER... THE UPSLOPE FLOW...ESPECIALLY WITH A MORE FAVORABLE WRLY FETCH LATE TONIGHT INTO EARLY THU WILL KEEP CIGS NEAR MVFR THRESHOLD DESPITE THE INCOMING DRY AIR UNTIL WINDS BACKING TO SW BRING IMPROVEMENT THU MORNING. OTHERWISE...VFR CONDITIONS ARE EXPECTED AT IWD AND SAW. ALTHOUGH MID CLOUDS WILL INCREASE THU...LINGERING LOW LEVEL DRY AIR WILL RESULT IN PREDOMINANT VFR CONDITIONS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 256 PM EST WED DEC 3 2014 STRONG WINDS AND LIGHT TO MODERATE FREEZING SPRAY POSSIBLE. A EXITING LOW NEAR JAMES BAY WILL KEEP A WEAKENING TROUGH ACROSS LAKE SUPERIOR. W-NW GALES OF 35-40KTS ARE EXPECTED INTO THIS EVENING. THE TROUGH WILL BE REPLACED BY HIGH PRESSURE SYSTEM OVERNIGHT INTO THURSDAY MORNING /WITH WINDS DIMINISHING/...BEFORE IT EXITS INTO S QUEBEC LATE THURSDAY. A LOW SLIDING ACROSS S CENTRAL CANADA THURSDAY AND THURSDAY NIGHT WILL CROSS LAKE SUPERIOR ON FRIDAY. BEHIND THIS LOW...A HIGH WILL BUILD IN FROM THE N PLAINS SATURDAY. THE HIGH WILL THEN PUSH ACROSS THE LOWER GREAT LAKES SATURDAY NIGHT. A LOW PRESSURE SYSTEM MAY ORGANIZE OVER SOUTH CENTRAL CANADA AND POSSIBLY CROSS INTO THE UPPER GREAT LAKES ON SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TITUS AVIATION...JLB MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
336 PM CST THU DEC 4 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 251 PM CST THU DEC 4 2014 SOUTHERLY WINDS CONTINUE THIS AFTERNOON AS HIGH PRESSURE PUSHES OFF TO THE EAST. THE CONCERN IN THE SHORT TERM PERIOD TURNS TO THE UPPER TROUGH AND ASSOCIATED SURFACE LOW MOVING EAST TO WEST ACROSS THE CENTRAL CONUS. ALL APPRECIABLE PRECIPITATION FROM THIS SYSTEM WILL STAY WELL SOUTH OF THE FA AS THE TRUE FORCING WILL SHIFT FROM NEAR OKLAHOMA THROUGH THE OHIO RIVER VALLEY REGION THROUGH FRIDAY EVENING. THIS SYSTEM WILL IMPACT OUR REGION TONIGHT THROUGH FRIDAY WITH WIDESPREAD LOW STRATUS COVER. THE QUESTION BECOMES WHETHER OR NOT ANY LIGHT PRECIP COULD BE RUNG OUT OF THIS LOW LEVEL MOISTURE. AN EVALUATION OF RAP AND NAM SOUNDINGS INDICATE THAT LOW LEVEL SATURATION BELOW 900H WITH A LITTLE LIFT PRESENT...WARRANTS THE MENTION OF FREEZING DRIZZLE WITH THE POSSIBILITY OF A FEW SNOWFLAKES. IN TERMS OF THE WESTERN EXTENT OF THE LOW CLOUDS...CONFIDENCE IS LOW...BUT STICKING WITH A BLEND OF THE NAM AND RAP GUIDANCE FOR NOW. WITH LITTLE MIXING TOMORROW...AND VERY MOIST LOW LEVEL PROFILES INDICATE LOW CLOUDS COULD LINGER FOR MOST OF THE DAY IN EASTERN AREAS. IN TERMS OF TEMPERATURES...SOUTHERLY WINDS AND A WARMER AIR MASS WILL MAKE FOR SLIGHTLY ABOVE NORMAL TEMPERATURES...WITH HIGHS EXPECTED IN THE 30S ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 251 PM CST THU DEC 4 2014 LONG TERM CONCERNS REMAIN THE MIXED PRECIPITATION THREAT DEVELOPING SUNDAY AND THEN THE WARMING TREND THROUGH NEXT WEEK. COOLER HIGH PRESSURE DROPS INTO THE AREA FRIDAY NIGHT AND SATURDAY. RETURN FLOW DEVELOPS AHEAD OF THE TROUGH THAT REMAINS OFF SHORE OF THE PACIFIC NORTHWEST. THIS TROUGH MOVES ASHORE FRIDAY NIGHT AND INTO THE DAKOTAS AND MINNESOTA ON SUNDAY. BUFKIT PROFILES INDICATE A NICE WARM LAYER ALOFT AS THE WARMER AIR LIFTS NORTH INTO THE AREA. THE TROUGH DEEPENS AND MOVES INTO THE AREA SUNDAY AND SUNDAY NIGHT. WE SHOULD SEE A WINTRY MIX OF FREEZING RAIN/SLEET AND SNOW CHANGING OVER TO SNOW FROM WEST TO EAST THROUGH SUNDAY. WILL INCLUDE THIS THREAT IN THE GRIDS AT THIS TIME. STILL A QUESTION HOW FAR EAST THIS WILL OCCUR AS THE VARIOUS DETERMINISTIC RUNS ARE STILL IN DISAGREEMENT ON HOW DEEP THE TROUGH DEVELOPS THROUGH SUNDAY. IT APPEARS THE NAM_WRF HAS TRENDED DEEPER WITH THE TROUGH...MORE DYNAMIC...WHICH MAY PRECLUDE SIGNIFICANT PERIOD OF MIXED PRECIPITATION. CONTINUED THE HIGH CHANCE POP TREND FOR NOW. THE THALER QG FROM THE NAM AND THE GFS SHOWS DECENT FORCING BEING GENERATED AHEAD OF THE TROUGH. IF THIS CONTINUES...WILL INCREASE POPS IN LATER FORECASTS. THE GFS IS THE WEAKEST...AND CONTINUES TO MOVE THE SURFACE LOW WELL NORTH OF THE AREA. COOLER AIR FOLLOWS THIS SYSTEM FOR MONDAY NIGHT AND TUESDAY. THEN SOME DISCREPANCY IN THE MODELS WITH THE POSSIBILITY OF ANOTHER TROUGH DROPPING SOUTH AND EAST OVER THE AREA FOR WEDNESDAY/THURSDAY TIME FRAME. THE ECMWF IS MORE BULLISH ON DEVELOPING A SYSTEM OVER THE AREA DURING THIS TIME PERIOD. WE CURRENTLY HAVE A DRY FORECAST FOR THE MID PART OF THE WEEK. BOTH MODELS SUGGEST THE UPPER RIDGE FINALLY PROPAGATES EAST INTO THE AREA BY NEXT WEEKEND. THIS SHOULD YIELD MUCH WARMER AIR WITH A GOOD SNOW MELT ANTICIPATED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1158 AM CST THU DEC 4 2014 VFR TO START THE PERIOD WITH MOSTLY CLEAR SKIES AND SOUTHERLY WINDS FOR THE REMAINDER OF THE AFTERNOON. STRATUS IS ADVANCING NORTH INTO SOUTHERN IOWA AT THIS TIME AHEAD OF A WEAK DEVELOPING SURFACE LOW. LOW LEVEL MOISTURE WILL CONTINUE TO STREAM NORTH IN THIS WAA REGIME WITH STRATUS EXPECTED TO SPREAD INTO SOUTHERN MN NEAR SUNDOWN AND BEYOND. RAP GUIDANCE SUGGESTS A FINE LINE BETWEEN VFR AND MVFR/IFR CIGS COULD CUT RIGHT THROUGH MINNESOTA...WITH A SHARP EDGE TO THE STRATUS DECK. AT THIS POINT...EXPECTING RESTRICTIONS FROM ST CLOUD EASTWARD...WITH THE LOWEST CONFIDENCE IN THAT ALONG THE WESTERN AREAS DUE TO PLACEMENT OF THE WESTERN EDGE OF STRATUS. THE HRRR ACTUALLY INDICATES THE CLOUD LINE TO BE JUST WEST OF MSP MUCH OF THE NIGHT. NAM SOUNDINGS ARE QUITE PESSIMISTIC AND HAVE BEEN CONSISTENT IN THAT. INTRODUCE IFR CIGS WITH BR LIKELY UNDER THE STRATUS OVERNIGHT. THE DETAILS WILL NEED TO BE IRONED OUT IN COMING ISSUANCE`S. STILL HAVE SOME CONCERN FOR -FZDZ IN WESTERN WI...HOWEVER JUST STUCK WITH BR FOR NOW IN THE TAFS. CLOUDS SHOULD LINGER IN EASTERN AREAS THROUGH FRIDAY...LIKELY RAISING TO MVFR LEVELS FOR MOST OF THE DAY. KMSP...HRRR AND RAP 0.5KM CONDENSATION PRESSURE DEFICITS INDICATE MSP COULD BE VERY CLOSE TO THE LOW LEVEL CLOUD LINE TONIGHT. THE NAM BLOWS THE LOW LEVEL SATURATION ACROSS A WIDER AREA...HOWEVER. SREF PROBS INDICATE CEILINGS SHOULD EXPAND WEST. BUT STILL EXPECT CEILINGS TO IMPACT MSP AT THIS TIME...BUT WITH LOW CONFIDENCE DUE TO THE PROXIMITY TO THE UNSATURATED AIR. /OUTLOOK FOR KMSP/ SAT...VFR. WINDS E/NE AT 5-10 KTS. SUN...VFR WITH MVFR/-SN POSSIBLE. WINDS S AT 10G20KTS. MON...VFR. POSSIBLE MVFR CIGS EARLY. WINDS WNW/NW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...SPD LONG TERM...DWE AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1224 PM CST THU DEC 4 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CST THU DEC 4 2014 MAIN CONCERN OVER THE NEXT 24 TO 30 HRS IS THE CHC OF --FZDZ/--SN AND FOG POTENTIAL AS MOISTURE BEGINS TO SURGE NORTHWARD AHEAD OF A STORM SYSTEM MOVING ACROSS THE SOUTHERN CONUS. THE ORIGIN OF THIS MOISTURE WAS ACROSS OK/KS/MO WHICH EARLY THIS MORNING HAD LOW CIGS/FOG/-RA AND DRIZZLE. SHORT TERM MODELS HAVE THIS AREA SURGING NORTHWARD THIS AFTN ACROSS IA...AND INTO FAR SOUTHERN MN BY LATE IN THE AFTN. ALTHOUGH I AM NOT CONVINCED OUR REGION WILL HAVE AREAS OF FOG THIS EVENING...PATCHY FOG AND SOME LIGHT PRECIPITATION IS POSSIBLE...ESPECIALLY TOWARD MIDNIGHT IN SC/EC MN AND WC WI. THIS IS WHERE WINDS IN THE LOWEST 3K REMAIN FROM THE S/SSW AND ADVECT THIS AREA OF MOISTURE NORTHWARD THRU THE DAY/OVERNIGHT. AS TEMPS HOLD NEAR OR BLW FREEZING...THE POTENTIAL OF FREEZING DRIZZLE EXISTS. THE BEST POTENTIAL OF FREEZING DRIZZLE WILL OCCUR IN WC WI WHERE BOTH THE DEPTH OF THE MOISTURE WILL BE HIGHER AND PERSIST THRU THE NIGHT. IN ADDITION...THE MOISTURE LAYER HAS TEMPS REMAINING BETWEEN -2C TO -8C. THEREFORE...VERY LITTLE CHC OF ICE CRYSTALS...SO THE MAIN FORM SHOULD BE FREEZING DRIZZLE. ANY FREEZING PRECIPITATION THAT DOES FALL SHOULD BE VERY LIGHT AND MAJOR TRAVEL PROBLEMS ARE NOT EXPECTED. WITH THE SOUTHERLY FLOW TODAY AND TONIGHT...TEMPS WILL RISE STEADY THRU THE DAY...AND LIKELY HOLD STEADY OR ONLY FALL A DEGREE OR TWO TONIGHT. WHERE THE SNOW COVER IS NON-EXISTENT IN SW MN...TEMPS WILL LIKELY RISE TO NEAR 40 DEGREES. 20S AND LOWER 30S SEEM REASONABLE ELSEWHERE. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 330 AM CST THU DEC 4 2014 THE MAIN CONCERN IN THE LONGER TERM CENTERS AROUND PRECIPITATION CHANCES FROM SUNDAY INTO MONDAY. OVER THE PAST 24 HOURS (2 RUNS) THE ECMWF HAS BACKED AWAY FROM A CLOSED MID LEVEL LOW DROPPING SOUTH ACROSS OUR AREA LATE SUNDAY INTO MONDAY. IT/S NOW FORECASTING A DEEP OPEN WAVE PROGRESSING EASTWARD ACROSS THE UPPER MISSISSIPPI VALLEY. THIS IS SIMILAR TO WHAT THE GFS HAS HAD FOR SEVERAL DAYS. THE GEM REMAINS THE OUTLIER WITH A CLOSED LOW DRIVING SOUTHEAST ACROSS THE DAKOTAS AND INTO IA BY MONDAY MORNING. OUR INTERNAL HOPWRF IS SIMILAR TO THE GFS BUT WEAKER AND FARTHER NORTH WITH A CLOSED UPPER LOW. THE DIFFERENT SOLUTIONS PROVIDE QUITE A VARIETY OF PRECIPITATION AMOUNTS. ON THE LOW END IS THE 4KM HOPWRF WITH ESSENTIALLY NO PRECIPITATION FORECAST SUNDAY-MONDAY. NEXT IS THE ECMWF WITH PERHAPS AN INCH OF SNOW ACROSS EASTERN MN AND WESTERN WI. THE GFS WOULD BE MORE IN THE 1 TO 2 INCH RANGE FOR THE SAME AREAS WHILE THE GEM WOULD BE IN THE 3 TO 4 INCH RANGE. FOLLOWED MORE OF A ECMWF/GFS BLEND WITH HIGH CHANCE POPS SPREADING EAST ON SUNDAY AND CONTINUING ACROSS EASTERN AREAS SUNDAY NIGHT AND MONDAY. ONE THING WHERE CONFIDENCE IS HIGH IS ON THE WIND SPEED FOR SUNDAY. STRONG SOUTHERLY WINDS WILL DEVELOP DURING THE DAY ACROSS WEST CENTRAL THROUGH SOUTH CENTRAL MN. SPEEDS FROM 20 TO 30 KNOTS SUSTAINED ARE LIKELY. THE 4KM HOPWRF SHOWS AREAS OF WESTERN LAC QUI PARLE COUNTY WITH NEAR 30 KNOT SUSTAINED WINDS LATE SUNDAY AFTERNOON/EVENING. HENCE...WINDS WERE RAISED CONSIDERABLY OVER GUIDANCE FOR WEST CENTRAL THROUGH SOUTH CENTRAL MN. ANOTHER CONCERN NEXT WEEK IS A CHANCE FOR PRECIPITATION LATE TUESDAY AND TUESDAY NIGHT. THE ECMWF HAS BEEN DRY DURING THIS PERIOD WHILE THE GFS HAS A SHORT WAVE AND SOME PRECIPITATION MOVING THOUGH. DP/DT ON THE GFS FOR TUESDAY EVENING SHOWS THAT THIS WAVE IS NOT BEING HANDLED WELL (NOT CONSISTENT). OVER THE PAST TWO RUNS THERE HAS BEEN A WEAKENING TREND WITH WHAT LOOKS LIKE A SPLIT DEVELOPING IN THE WAVE WITH PIECES PASSING NORTH AND SOUTH OF US. AT THIS POINT...WE LOWERED THE SLIGHT CHANCE POPS FROM THE BLENDED GUIDANCE AND MAINTAINED A DRY FORECAST. TEMPERATURES WILL BE NEAR SEASONAL LEVELS THROUGH MUCH OF THE PERIOD. EXCEPTIONS ARE SATURDAY AND TUESDAY WHERE HIGHS WILL ONLY BE IN THE LOWER TO MIDDLE 20S. HIGHS WERE BUMPED UP A BIT OVER GUIDANCE ON SUNDAY WITH LOWER TO MIDDLE 30S FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1158 AM CST THU DEC 4 2014 VFR TO START THE PERIOD WITH MOSTLY CLEAR SKIES AND SOUTHERLY WINDS FOR THE REMAINDER OF THE AFTERNOON. STRATUS IS ADVANCING NORTH INTO SOUTHERN IOWA AT THIS TIME AHEAD OF A WEAK DEVELOPING SURFACE LOW. LOW LEVEL MOISTURE WILL CONTINUE TO STREAM NORTH IN THIS WAA REGIME WITH STRATUS EXPECTED TO SPREAD INTO SOUTHERN MN NEAR SUNDOWN AND BEYOND. RAP GUIDANCE SUGGESTS A FINE LINE BETWEEN VFR AND MVFR/IFR CIGS COULD CUT RIGHT THROUGH MINNESOTA...WITH A SHARP EDGE TO THE STRATUS DECK. AT THIS POINT...EXPECTING RESTRICTIONS FROM ST CLOUD EASTWARD...WITH THE LOWEST CONFIDENCE IN THAT ALONG THE WESTERN AREAS DUE TO PLACEMENT OF THE WESTERN EDGE OF STRATUS. THE HRRR ACTUALLY INDICATES THE CLOUD LINE TO BE JUST WEST OF MSP MUCH OF THE NIGHT. NAM SOUNDINGS ARE QUITE PESSIMISTIC AND HAVE BEEN CONSISTENT IN THAT. INTRODUCE IFR CIGS WITH BR LIKELY UNDER THE STRATUS OVERNIGHT. THE DETAILS WILL NEED TO BE IRONED OUT IN COMING ISSUANCE`S. STILL HAVE SOME CONCERN FOR -FZDZ IN WESTERN WI...HOWEVER JUST STUCK WITH BR FOR NOW IN THE TAFS. CLOUDS SHOULD LINGER IN EASTERN AREAS THROUGH FRIDAY...LIKELY RAISING TO MVFR LEVELS FOR MOST OF THE DAY. KMSP...HRRR AND RAP 0.5KM CONDENSATION PRESSURE DEFICITS INDICATE MSP COULD BE VERY CLOSE TO THE LOW LEVEL CLOUD LINE TONIGHT. THE NAM BLOWS THE LOW LEVEL SATURATION ACROSS A WIDER AREA...HOWEVER. SREF PROBS INDICATE CEILINGS SHOULD EXPAND WEST. BUT STILL EXPECT CEILINGS TO IMPACT MSP AT THIS TIME...BUT WITH LOW CONFIDENCE DUE TO THE PROXIMITY TO THE UNSATURATED AIR. /OUTLOOK FOR KMSP/ SAT...VFR. WINDS E/NE AT 5-10 KTS. SUN...VFR WITH MVFR/-SN POSSIBLE. WINDS S AT 10G20KTS. MON...VFR. POSSIBLE MVFR CIGS EARLY. WINDS WNW/NW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...RAH AVIATION...SPD
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
326 AM CST Thu Dec 4 2014 .DISCUSSION... Issued at 325 AM CST THU DEC 4 2014 Dry air across the region is making it difficult for low-level moisture to make it this far north, and drizzle chances are quickly decreasing as a result. At 3 AM low clouds and light drizzle have only made it as far north as Joplin and Chanute and probably won`t make it into east central KS and west central MO until 6 AM at the earliest with a better push further east toward Clinton and Boonville after 6 AM. At this point it`s looking unlikely that precipitation will be able to make it much further north or west than a Butler- Marshall- Moberly line, and drizzle has been taken out of the forecast for Kansas City and surrounding areas. Even for areas that do see drizzle, temperatures have remained above freezing and look to generally stay that way through the morning. Can`t rule out that wetbulb effects could briefly bring some areas below freezing wherever precipitation does materialize but it may not be heavy enough to do this for very long. One exception may be the Moberly area where temperatures have been hovering around 32 overnight. Bottom line is that the potential for hazardous icing is quickly decreasing and travel problems should be few and far between this morning. A much stronger batch of precipitation will organize late tonight into Friday morning as a weak wave approaches the area and synoptic- scale ascent becomes much better organized. While the main upper wave isn`t particularly strong, the combination of strong upper divergence between two upper jet maxima and deep low-level isentropic ascent will be supportive of widespread rainfall amounts of a half inch or more. In fact, a band of persistent frontogenesis and unseasonably high precipitable water amounts over an inch could lead to a band of 1"+ rainfall amounts near or just south of the I-70 corridor. It still looks like all areas will stay above freezing through this event so that all precipitation will fall as rain. The forecast beyond Friday still looks uneventful with no systems of note other than a weak front on Monday. While this system could produce a couple of light rain or snow showers, dry air looks to prevent much if any measurable precipitation. Temperatures will remain close to seasonal averages through the period. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1123 PM CST WED DEC 3 2014 325 AM UPDATE...Chances for freezing drizzle at the KC area terminals are decreasing this morning. Any precipitation chances look to be well to the east and southeast of the area, while temperatures should stay near or above freezing. Have therefore removed any mention of freezing precipitation from the TAFs. MVFR ceilings will fill in across the area overnight as low level moisture moves into the region. Mid-level deck of 6-7kft has already begun to develop along and south of an KOJC to KDMO line. Conditions continue to look favorable for freezing drizzle to develop between 10-12Z at KIXD, KMKC, and KMCI. KSTJ is still looking to be on the very edge of precipitation so have left it out of the current TAF period. Latest HRRR model run and bufkit soundings show ceilings dropping down to IFR once drizzle begins. Once temperatures climb above freezing tomorrow morning, just drizzle can be expected through early afternoon. By afternoon, drizzle will wane but ceilings are still expected to remain IFR to MVFR through the remainder of the period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...Hawblitzel AVIATION...PMM
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1248 AM CST Thu Dec 4 2014 .UPDATE... Issued at 1247 AM CST THU DEC 4 2014 Reports of drizzle have spread north from Tulsa into extreme southeast KS this morning, and several short-range models still bring drizzle into much of the forecast area by 12Z. This activity will be encountering dry surface air this far north though where dewpoints are still around 20 degrees. This will probably keep much drizzle from materializing as quick as models indicate, but could still see some light patches developing near and south of the Missouri River by 6 AM or so. One big question is if temperatures can drop below freezing, as easterly flow and thickening clouds have kept them steady in the mid 30s for the past several hours. Much of the short range guidance keeps temperatures above freezing for most areas near and south of the Missouri River. However, given the dewpoints, it wouldn`t be surprising to see wetbulb effects produce some sub- freezing temperatures where drizzle develops, so will keep the freezing drizzle mention going for areas near the US 50 and I-70 corridors for the early morning hours. Butler and Clinton areas may be out of the woods if these temperature trends continue. && .DISCUSSION... Issued at 300 PM CST WED DEC 3 2014 Conditions continue to look favorable for a window of freezing drizzle tomorrow morning, right around the morning commute. Latest satellite and surface observations show thicker lower-level moisture poised across Oklahoma and Arkansas. Models continue to show this moisture advecting northward later tonight in response to a weak wave moving across the Central Plains. This will help produce broad but weak isentropic ascent within this low-level moisture, providing enough lift to get drizzle/freezing drizzle into the area late tonight/early tomorrow morning. Temperatures have warmed into the middle 40s for much of the area this afternoon and latest guidance suggest that temperatures may not be as cool tonight as a result. However... temperatures are still expected to fall below freezing across much of the area before this moisture works northward and as a result it looks like there will be several hour window, around the morning commute, when freezing drizzle will be possible. Given this setup, a light glazing is possible on area roads late tonight/early tomorrow morning, which could lead to a treacherous morning commute for some folks. As temperatures warm through the morning hours, likely within an hour or two of sunrise for the Kansas City area, a transition to just drizzle will occur, ending any potential for a light glazing across the area. This freezing drizzle/drizzle event should wind down by the afternoon hours with focus then shifting to the Thursday night and Friday time frame. The next short wave trough is expected to move across the area late Thursday and Friday. With moisture in place, better forcing aloft should lead to more widespread rainfall across the area. The heaviest rain amounts look to be along and south of I-70, where amounts may be upwards of an inch. With temperatures expected to be above freezing throughout the forecast area, this should be rainfall for the entire area. The only areas where this could be in question would be across far northern Missouri. But for now, temperatures look to remain above freezing there as well, so the possibility of freezing rain looks unlikely at this point in time. The forecast for the extended looks relatively quiet with temperatures close to normal. The one exception to this may be a system that clips the area Sunday into Monday. Models show a clipper system moving across the Upper Midwest with some trailing vorticity moving across northern Missouri Sunday night/early Monday. This may provide enough forcing to get some rain Sunday or a mix during the overnight hours. After this system moves through, a ridge is expected to build eastward and strengthen. This should result in a warming trend with quiet weather for the later half of next week. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1123 PM CST WED DEC 3 2014 MVFR ceilings will fill in across the area overnight as low level moisture moves into the region. Mid-level deck of 6-7kft has already begun to develop along and south of an KOJC to KDMO line. Conditions continue to look favorable for freezing drizzle to develop between 10-12Z at KIXD, KMKC, and KMCI. KSTJ is still looking to be on the very edge of precipitation so have left it out of the current TAF period. Latest HRRR model run and bufkit soundings show ceilings dropping down to IFR once drizzle begins. Once temperatures climb above freezing tomorrow morning, just drizzle can be expected through early afternoon. By afternoon, drizzle will wane but ceilings are still expected to remain IFR to MVFR through the remainder of the period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...Hawblitzel DISCUSSION...CDB AVIATION...PMM
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1140 PM CST Wed Dec 3 2014 .DISCUSSION... Issued at 300 PM CST WED DEC 3 2014 Conditions continue to look favorable for a window of freezing drizzle tomorrow morning, right around the morning commute. Latest satellite and surface observations show thicker lower-level moisture poised across Oklahoma and Arkansas. Models continue to show this moisture advecting northward later tonight in response to a weak wave moving across the Central Plains. This will help produce broad but weak isentropic ascent within this low-level moisture, providing enough lift to get drizzle/freezing drizzle into the area late tonight/early tomorrow morning. Temperatures have warmed into the middle 40s for much of the area this afternoon and latest guidance suggest that temperatures may not be as cool tonight as a result. However... temperatures are still expected to fall below freezing across much of the area before this moisture works northward and as a result it looks like there will be several hour window, around the morning commute, when freezing drizzle will be possible. Given this setup, a light glazing is possible on area roads late tonight/early tomorrow morning, which could lead to a treacherous morning commute for some folks. As temperatures warm through the morning hours, likely within an hour or two of sunrise for the Kansas City area, a transition to just drizzle will occur, ending any potential for a light glazing across the area. This freezing drizzle/drizzle event should wind down by the afternoon hours with focus then shifting to the Thursday night and Friday time frame. The next short wave trough is expected to move across the area late Thursday and Friday. With moisture in place, better forcing aloft should lead to more widespread rainfall across the area. The heaviest rain amounts look to be along and south of I-70, where amounts may be upwards of an inch. With temperatures expected to be above freezing throughout the forecast area, this should be rainfall for the entire area. The only areas where this could be in question would be across far northern Missouri. But for now, temperatures look to remain above freezing there as well, so the possibility of freezing rain looks unlikely at this point in time. The forecast for the extended looks relatively quiet with temperatures close to normal. The one exception to this may be a system that clips the area Sunday into Monday. Models show a clipper system moving across the Upper Midwest with some trailing vorticity moving across northern Missouri Sunday night/early Monday. This may provide enough forcing to get some rain Sunday or a mix during the overnight hours. After this system moves through, a ridge is expected to build eastward and strengthen. This should result in a warming trend with quiet weather for the later half of next week. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1123 PM CST WED DEC 3 2014 MVFR ceilings will fill in across the area overnight as low level moisture moves into the region. Mid-level deck of 6-7kft has already begun to develop along and south of an KOJC to KDMO line. Conditions continue to look favorable for freezing drizzle to develop between 10-12Z at KIXD, KMKC, and KMCI. KSTJ is still looking to be on the very edge of precipitation so have left it out of the current TAF period. Latest HRRR model run and bufkit soundings show ceilings dropping down to IFR once drizzle begins. Once temperatures climb above freezing tomorrow morning, just drizzle can be expected through early afternoon. By afternoon, drizzle will wane but ceilings are still expected to remain IFR to MVFR through the remainder of the period. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...CDB AVIATION...PMM
AREA FORECAST DISCUSSION
NWS BILLINGS MT
305 PM MST THU DEC 4 2014 .SHORT TERM...VALID FOR FRI AND SAT... UPPER LEVEL RIDGE AMPLIFICATION OVER THE PACIFIC NORTHWEST DURING THE NEXT 24 HOURS IS FOLLOWED BY THIS RIDGE WEAKENING BUT ITS AXIS SHIFTING EASTWARD. BUILDING HEIGHTS OVER THE AREA SHOULD STABILIZE THE AIRMASS BUT MOISTURE IS STILL FLOWING OVER THE RIDGE INTO THE AREA. CURRENTLY RADAR SHOWS LIGHT RETURNS ACROSS THE AREA BUT LATEST RUC MODEL ONLY MAINTAINS A COUPLE OF SIGNATURES OVERNIGHT SO MOST OF THE AREA WILL BE DRY. ONE OF THE TWO AREAS OF PRECIPITATION WILL BE THE MOUNTAINS WHICH WILL CONTINUE TO SEE OROGRAPHIC SNOW BUT DYNAMIC FORCING IS WEAK. THE OTHER AREA IS OVER NORTHERN PORTIONS OF SOUTHEAST MONTANA WHERE A FRONTAL BOUNDARY SAGS SOUTH INTO THE AREA IN RESPONSE TO THE DEVELOPMENT OF THE UPSTREAM RIDGE. THINK THAT MOST OF THIS PRECIPITATION WILL BE A RAIN SNOW MIX GIVEN THE MIXING THAT OCCURRED TODAY AS OPPOSED TO ANY FREEZING RAIN. TOMORROW THIS FRONTAL BOUNDARY REMAINS OVER SOUTHEAST MONTANA AND THE SURFACE TROUGH SHIFTS TO THE FOOTHILLS WHICH WILL CAUSE A LOW LEVEL EASTERLY FLOW AND COOLER TEMPERATURES. AIRMASS DOES DRY OUT SO DO NOT EXPECT ANY PRECIPITATION. AS THE RIDGE AXIS MOVES THROUGH THE AREA FRIDAY NIGHT IT BRINGS A DOWNSLOPE IT ALLOWS A SOUTHWEST FLOW ALOFT TO SET IN AND A LEESIDE TROUGH DOWNSLOPE PATTERN TO EVOLVE. THIS WILL BRING WARMER TEMPERATURES AND CONTINUED DRY CONDITIONS. BY SATURDAY NIGHT SOME COOLING OVER IDAHO ALLOWS A GAP FLOW PATTERN TO EVOLVE BUT STABILITY DOES NOT LOOK TO BE OPTIMAL FOR WINDS BEING TOO STRONG. BORSUM .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... EXTENDED FORECAST REMAINS UNCHANGED FOR THE END OF THE WEEKEND THROUGH THE MIDDLE OF NEXT WEEK. THE PATTERN REMAINS THE SAME WITH WEAK DISTURBANCES MOVING ACROSS THE FORECAST AREA FOLLOWED BY BRIEF RIDGING ALONG WITH PERIODS OF WINDS ACROSS OUR WESTERN AREAS. A DISTURBANCE MOVING ACROSS THE NORTHERN PORTIONS OF THE STATE SATURDAY NIGHT INTO SUNDAY WILL FLATTEN SATURDAYS RIDGE BRINGING A NORTHWEST FLOW ALOFT TO THE FORECAST AREA SUNDAY. RIDGING BUILDS AGAIN FOR MONDAY ALONG WITH SOME WEAK LEE-SIDE TROUGHING. A FAST ZONAL FLOW ALOFT MOVES ACROSS THE FORECAST AREA TUESDAY BEFORE STRONGER RIDGING BUILDS WEDNESDAY INTO THURSDAY AS A LARGE TROUGH MOVES ONTO THE WEST COAST. PRECIP CHANCES WILL MOSTLY BE CONFINED TO MOUNTAIN SNOW SHOWERS...MAINLY THE WEST FACING SLOPES OF THE BEARTOOTH/ABSAROKAS. TEMPERATURES WILL RUN WELL ABOVE NORMAL WITH READINGS IN THE 40S AND 50S...WITH A 60 DEGREE READING NOT OUT OF THE QUESTION BY NEXT WEDNESDAY OR THURSDAY. HOOLEY && .AVIATION... SKIES WILL BE MOSTLY CLOUDY OVERNIGHT AS MID AND HIGH LEVEL CLOUDS MOVE ACROSS THE FORECAST AREA. A SLIGHT CHANCE FOR A SPRINKLE OR FLURRY WILL EXIST. HOWEVER...NO AVIATION HAZARDS ARE EXPECTED AS VFR CONDITIONS WILL PREVAIL. SNOW SHOWERS WILL CONTINUE OVER THE MOUNTAINS RESULTING IN MOUNTAIN OBSCURATIONS AT TIMES. HOOLEY && .PRELIMINARY POINT TEMP/POPS... FRI SAT SUN MON TUE WED THU ----------------------------------------------------------- BIL 027/038 024/045 031/045 026/045 030/046 030/049 032/050 11/E 00/B 10/N 00/B 12/W 11/B 11/B LVM 032/046 031/048 032/044 029/046 034/045 034/047 034/048 11/E 01/N 11/N 00/B 12/W 11/N 11/B HDN 021/037 018/044 026/044 022/044 025/047 028/049 025/050 11/E 00/B 00/U 00/B 01/B 11/B 10/B MLS 015/030 018/039 027/040 020/040 025/043 027/046 028/047 21/B 00/B 11/B 00/U 01/B 11/U 10/B 4BQ 019/037 021/043 026/043 020/043 025/045 026/047 027/048 11/B 00/B 11/B 00/U 00/B 00/B 00/B BHK 015/029 016/036 025/038 020/036 023/043 028/044 030/045 30/B 10/B 11/B 10/B 01/B 00/B 00/B SHR 024/043 022/046 025/045 022/043 026/047 026/049 026/050 01/B 00/B 10/U 00/U 00/B 10/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
928 PM MST WED DEC 3 2014 .UPDATE... SOME SIGNIFICANT UPDATES TO THE FORECAST THIS EVENING. LATEST MODEL RUNS HAVE POINTED A STRONG SURGE OF MID LEVEL (H7-H5) MOISTURE INTO THE AREA LATE TONIGHT THROUGH THE DAY TOMORROW. THIS MOISTURE IS ALREADY IMPACTING OUR WESTERN MOUNTAINS WITH SNOW BASED ON THE COOKE CITY WEB CAM AND SNOTEL MEASUREMENTS. LATEST MET GUIDANCE BUMPED PRECIPITATION CHANCES WAY UP FROM ITS PREVIOUS RUNS AND HRRR SHOWING INCREASED PRECIPITATION LEE OF THE MOUNTAINS FOR TOMORROW. AS A RESULT OF THIS MOISTURE PUSH HAVE INCREASED MOUNTAIN POPS TO CATEGORICAL FOR WEST FACING SLOPES WITH CHANCE POPS FOR THE EASTERN SIDE. BROUGHT LOW POPS INTO WESTERN VALLEYS BY SUNRISE AND SPREAD THEM EAST INTO ROSEBUD COUNTY BY LATE MORNING. THERE IS A STRONG DOWNSLOPE WIND ASSOCIATED WITH THIS SYSTEM BUT MODELS ALL CONSISTENT WITH SEEING SOME LIGHT PRECIPITATION MAKING IT TO THE GROUND TOMORROW. NEXT CHALLENGE IS PRECIPITATION TYPE WITH LOWER RIVER VALLEYS CURRENTLY WELL BELOW FREEZING WHILE MANY HILLTOP LOCATIONS ARE AT OR ABOVE FREEZING. WITH CLOUD COVER INCREASING TEMPERATURES PROBABLY WON`T GO A WHOLE LOT LOWER THAN CURRENT READINGS. WESTERLY WIND WILL BEGIN TO SCOUR OUT RIVER VALLEY COLD AIR TOMORROW MORNING. THIS WILL LIKELY LEAD TO A MIX OF RAIN/FREEZING RAIN/AND MAYBE SNOW ACROSS THE AREA DURING THE MORNING HOURS WITH LOWEST VALLEYS SEEING THE BEST SHOT AT FREEZING RAIN. THIS INCLUDES THE YELLOWSTONE AND BIGHORN VALLEYS AND PORTIONS OF BOTH I-90/I-94. IN ADDITION COULD SEE SOME RAIN FALL AT TEMPERATURES ABOVE FREEZING BUT WITH FROZEN GROUND IT MAY FREEZE ON CONTACT ANYWAY. THOSE TRAVELING IN THE MORNING SHOULD BE ALERT FOR ANY RAIN AND TREAT IT AS FREEZING RAIN...EXPECTING SLICK ROADS UNTIL LATE MORNING WHEN THE SUN SHOULD BRING UP ROAD TEMPERATURES ABOVE FREEZING. BY AFTERNOON MOST PRECIPITATION NOT IN THE MOUNTAINS WILL BE RAIN...BUT WILL NEED TO WATCH AREAS AROUND MILES CITY AND BROADUS FOR ADDITIONAL FREEZING RAIN. CHAMBERS && .SHORT TERM...VALID FOR THU AND FRI... ROUND OF CLEARING OVER WESTERN AREAS THIS AFTERNOON HAS LET SOME OF THE MOUNTAIN TEMPERATURES CLIMB BUT LOWER ELEVATIONS HAVE STRUGGLED TO MIX OUT FULLY. SURFACE TROUGH LAYING OVER THE AREA PROGGED TO LINGER OVERNIGHT WHICH WILL COMBINE WITH SURFACE HIGH PRESSURE OVER YELLOWSTONE PARK TO SUPPORT A DOWNSLOPE FLOW FOR THE WESTERN ZONES...ALBEIT LIGHT. WILL BE ENOUGH TO SUPPORT SOME MILDER TEMPERATURES THAN PREVIOUS NIGHT BUT THE NORTH SIDE OF THE TROUGH INCLUDING MOST OF SOUTHEAST MONTANA WILL APPROACH THE SINGLE DIGITS AGAIN. SECOND SURGE OF MOISTURE MOVING INTO SOUTHWEST IDAHO DOES SHIFT UP INTO SOUTHWEST MONTANA TONIGHT WHICH WILL BRING A CHANCE FOR MOUNTAIN SHOWER ACTIVITY. THE SURFACE TROUGH MOVES LITTLE TOMORROW BUT THE DOWNSLOPE FLOW SHOULD BE MAINTAINED TO SUPPORT A WARMER DAY ACROSS THE WESTERN ZONES. AN AMPLIFYING RIDGE OVER THE PACIFIC NORTHWEST ALLOWS SURFACE HIGH PRESSURE OVER ALBERTA TO DESCEND INTO NORTHEAST MONTANA THURSDAY NIGHT TIGHTENING UP GRADIENTS ALONG THE SURFACE TROUGH AND PRODUCING A BIT OF WEAK FRONTOGENESIS. OVERALL A VERY WEAK DYNAMIC SITUATION BUT ENOUGH TO HAVE SOME ISOLATED POPS OFF OF THE MOUNTAINS ALONG THE PROJECTED LOCATION OF THE BOUNDARY THURSDAY NIGHT INTO EARLY FRIDAY. RIDGE AXIS SLIDING TOWARDS THE AREA ON FRIDAY DOES BEGIN TO MOVE THE SURFACE TROUGH EASTWARD LATER IN THE DAY AND BRINGS IN DRYING CONDITIONS. THIS WILL END THE CHANCE OF PRECIPITATION AND BRING ANOTHER LITTLE PUSH IN THE TEMPERATURES UPWARDS. MODELS LOOK LIKE THEY ARE TRYING TO DEVELOP A WIND PATTERN FOR GAP FLOW AREAS FRIDAY NIGHT SO INCREASED WIND SPEEDS FOR THOSE AREAS. BORSUM .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... NO BIG STORM SYSTEMS LOOK ON THE HORIZON THROUGH THE EXTENDED PERIOD. OVERALL...IT LOOKS TO BE QUIET WITH ABOVE NORMAL TEMPERATURES. LARGE- SCALE WEATHER PATTERN WILL BE A RIDGE-TROUGH PATTERN EVERY OTHER DAY OR SO. SATURDAY STARTS WITH A RIDGE BUT AN UPPER LOW AND TROUGH MOVE ACROSS THE CANADIAN BORDER SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING A PERIOD OF WINDS TO THE AREA BUT NOTHING STRONG AT THIS POINT ALONG WITH A SLIGHT CHANCE FOR SHOWERS...MAINLY MOUNTAIN SNOW SHOWERS. RIDGING ARRIVES BRIEFLY FOR MONDAY FOLLOWED BY ANOTHER WEAK WAVE FLATTENING THE RIDGE TUESDAY INTO WEDNESDAY. MAIN THEME IS A FAST FLOW ALOFT WITH SNOW SHOWER CHANCES MAINLY FOR THE WEST FACING SLOPES OF THE BEARTOOTH/ABSAROKA MOUNTAINS. TEMPERATURES WILL RUN ON AVERAGE ABOUT 10 DEGREES ABOVE NORMAL FOR MOST LOCATIONS ACROSS THE PLAINS WITH READINGS IN THE 40S TO POSSIBLY 50 DEGREES. HOOLEY && .AVIATION... VFR WILL PREVAIL OVER THE AREA TONIGHT. ON THU...SCATTERED RAIN AND SNOW SHOWERS MAY PRODUCE MVFR CONDITIONS W OF KBIL...INCLUDING OVER KLVM. IN ADDITION...THERE WILL BE A SLIGHT CHANCE OF A MIX OF RAIN...SNOW AND LIGHT FREEZING RAIN FROM ROSEBUD COUNTY W THU MORNING. IN THE AFTERNOON...THERE WILL BE A SLIGHT CHANCE OF A MIX OF RAIN...SNOW AND LIGHT FREEZING RAIN FROM KMLS W THROUGH N ROSEBUD COUNTY. OTHERWISE...EXPECT VFR OVER THE AREA. SNOW SHOWERS OVER THE MOUNTAINS WILL PRODUCE WIDESPREAD OBSCURATIONS OVER THE BEARTOOTHS...ABSAROKAS AND CRAZYS TONIGHT THROUGH THU. EXPECT AREAS OF OBSCURATION OVER THE NE BIGHORNS. ARTHUR && .PRELIMINARY POINT TEMP/POPS... THU FRI SAT SUN MON TUE WED ----------------------------------------------------------- BIL 020/043 027/041 026/050 027/045 024/045 025/045 029/046 03/O 11/B 10/B 10/N 00/B 12/W 11/B LVM 035/046 031/045 032/050 028/044 026/045 028/044 031/044 24/R 11/E 10/N 21/N 00/B 12/W 11/N HDN 012/041 021/040 020/050 025/044 019/044 020/045 024/046 03/O 11/B 10/B 10/B 00/B 11/B 11/B MLS 008/035 015/032 020/044 026/039 017/041 019/043 024/043 02/S 11/B 10/B 11/B 00/B 11/B 11/B 4BQ 014/041 020/038 024/044 026/041 018/043 020/044 024/044 01/B 11/B 10/B 11/B 00/U 01/B 00/B BHK 010/038 014/030 018/040 026/036 015/036 018/040 024/041 01/B 01/B 10/U 11/N 00/B 01/B 00/B SHR 010/046 024/043 022/049 023/045 021/043 022/047 023/045 02/O 11/B 00/B 10/B 00/B 01/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
600 PM CST FRI DEC 5 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 218 PM CST FRI DEC 5 2014 THE SHORT TERM FORECAST THROUGH SATURDAY IS RELATIVELY QUIET IN TERMS OF MAJOR WEATHER ISSUES. MILD TEMPERATURES THIS AFTERNOON WILL BE TEMPERED A BIT IN THE WAKE OF FRONTAL BOUNDARY PASSING THROUGH THE FORECAST AREA AT THIS TIME. TEMPERATURES WILL ACTUALLY BE NEAR NORMAL TONIGHT AND SATURDAY...THOUGH IT WILL FEEL QUITE A BIT COOLER TONIGHT WITH UPPER TEENS AND 20S. DECENT MODEL AGREEMENT WITH SOME LOWER CLOUDS TRYING TO SNEAK BACK WEST TONIGHT AND PUSH INTO THE HIGHWAY 81 CORRIDOR AREA TOWARD DAWN SATURDAY AND LINGER INTO THE MORNING. HAVE INCREASED CLOUDS IN THAT AREA...AND ADDED A BIT OF PATCHY FOG FOG WHICH ALIGNS WELL WITH WFOS OMAHA AND TOPEKA FORECAST. SOME CONCERN OF FOG IN THE NORTHWEST PART OF THE FORECAST AREA...WHERE WINDS TURN NEARLY CALM. HRRR HINTS AT LOWER CLOUDS AND VISIBILITY OVER PARTS OF THE SANDHILLS. WILL HOLD OFF FOR NOW BUT WORTH NOTING HEADING INTO TONIGHT. BEYOND THAT...SATURDAY WILL SEE MID/HIGH CLOUDS START TO INCREASE FROM THE WEST IN THE AFTERNOON AS WARM ADVECTION INCREASES AHEAD OF NEXT WEATHER SYSTEM ON SUNDAY. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 218 PM CST FRI DEC 5 2014 GUIDANCE SUGGESTS THE LONG-TERM FORECAST PERIOD WILL START OFF WITH UPPER TROPOSPHERIC RIDGING OVER THE CENTRAL CONUS AND A SUBTLE TROUGH AXIS JUST WEST OF THE ROCKY MOUNTAINS AT 00Z SUNDAY. THIS TROUGH AXIS IS EXPECTED TO SHIFT EAST SATURDAY NIGHT INTO SUNDAY...WITH THIS TROUGH AXIS LIKELY CLEARING OUR AREA DURING THE DAY SUNDAY. NORTHWESTERLY UPPER TROPOSPHERIC FLOW IS THEN EXPECTED TO OVERTAKE THE CENTRAL CONUS THROUGH MUCH OF THE REMAINDER OF THE LONG-TERM FORECAST PERIOD AS UPPER TROPOSPHERIC TROUGHING STRENGTHENS OVER THE EASTERN CONUS AND RIDGING BUILDS ACROSS THE WEST. ALTHOUGH UNCERTAINTY REMAINS...THERE REMAIN HINTS AT A BRIEF PERIOD OF PRECIPITATION PRODUCTION ACROSS THE CENTRAL PLAINS ON SUNDAY AS TROPOSPHERIC MOISTURE AND UPPER TROPOSPHERIC THERMAL ADVECTION INCREASES AHEAD OF THE APPROACHING TROUGH AXIS. QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL CONTINUE TO SUGGEST LIGHT PRECIPITATION WILL BE REALIZED ACROSS PORTIONS OF OUR CWA ON SUNDAY AND AS A RESULT...CONTINUED WITH POPS...ALBEIT LOW...ACROSS MUCH OF THE AREA ON SUNDAY. UNFORTUNATELY PRECIPITATION TYPE REMAINS QUESTIONABLE AS FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST AN ELEVATED WARM LAYER WILL LIKELY PROVIDE LIQUID PRECIPITATION WHILE SURFACE TEMPERATURE READINGS FALL TO NEAR OR BELOW FREEZING AROUND DAYBREAK SUNDAY. PREVIOUS SHIFT WENT AHEAD AND INSERTED A MENTION OF LIGHT FREEZING RAIN FOR A TIME SUNDAY MORNING AND AT THIS TIME...SEE NO REASON TO REMOVE THIS WORDING. GIVEN ALL THIS...A SLIGHT CHANCE FOR LIGHT FREEZING RAIN REMAINS IN THE FORECAST FOR MUCH OF THE AREA FOR A FEW HOURS SUNDAY MORNING AROUND DAYBREAK...WITH LIGHT RAIN THEN FORECAST BY 14Z AS SURFACE TEMPERATURE READINGS CLIMB ABOVE FREEZING. THERE MAY ALSO BE A PERIOD OF LIGHT DRIZZLE OR LIGHT FREEZING DRIZZLE ACROSS PORTIONS OF THE CWA SUNDAY MORNING...WITH GUIDANCE SUGGESTING 0-1KM RELATIVE HUMIDITY VALUES NEAR 100% WILL ACCOMPANY 0- 1KM BULK SHEAR VALUES OF 25-30KTS. GIVEN THE POTENTIAL FOR A SATURATED LOWER TROPOSPHERE AS WELL AS SUFFICIENT TURBULENT MIXING...OPTED TO KEEP A MENTION OF LIGHT DRIZZLE AND LIGHT FREEZING DRIZZLE GOING IN THE FORECAST FOR SUNDAY MORNING. AN OVERALL LACK IN OMEGA SHOULD THEN KEEP US DRY THROUGH MUCH OF THE REST OF THE LONG-TERM FORECAST PERIOD...ALTHOUGH THERE ARE HINTS OF AN UPPER TROPOSPHERIC SHORT WAVE PERHAPS BRINGING A ROUND OF LIGHT PRECIPITATION TO THE REGION ON FRIDAY AND AS A RESULT...WENT WITH A LOW POP ACROSS PORTIONS OF THE CWA ON FRIDAY. LITTLE IF ANY CHANGE IN BOUNDARY-LAYER AIR MASS SHOULD PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE LONG-TERM FORECAST PERIOD...WITH HIGHS IN THE UPPER 40S TO MID 50S AND LOW IN THE UPPER 20S TO LOWER 30S CURRENTLY FORECAST FOR THE MOST PART. && .AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 559 PM CST FRI DEC 5 2014 VFR CONDITIONS. WIND WILL BECOME MORE EAST/SOUTHEAST SATURDAY. ANY REDUCED VIS SHOULD STAY SOUTHEAST OF THE TERMINALS TONIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...NOAA/NWS/MORITZ LONG TERM...BRYANT AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
535 PM CST FRI DEC 5 2014 .SYNOPSIS... ISSUED AT 322 PM CST FRI DEC 5 2014 WEAK COLD FRONT STALLING NEAR THE KS/NEB BORDER THIS AFTERNOON. MOSTLY SUNNY SKIES AND SOME 10 TO 15 MPH NORTHERLY WINDS BEHIND THE FRONT HAVE ALLOWED FOR GOOD MIXING WITH TEMPERATURES IN THE UPPER 40S AND 50S. MEANWHILE HIGH PRESSURE IS SETTLING ACROSS THE NORTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 TONIGHT HIGH PRESSURE WILL CONTINUE TO DRIFT ACROSS THE NORTHERN PLAINS. THIS WILL CAUSE THE WINDS TO BECOME EASTERLY/SOUTHEASTERLY. THIS WIND SWITCH WILL HELP TO USHER IN SOME LL MOISTURE. THIS WILL COMBINE WITH MOSTLY CLEAR SKIES AND GOOD RADIATIONAL COOLING TO PRODUCE LOWS IN THE TEENS AND MAYBE SOME PATCHY FOG. SOME CONCERNS TOWARDS THE FOG DEVELOPMENT AS AFTERNOON TEMPS IN THE 50S MIXED THE MOISTURE FAIRLY WELL. ALSO A VERY DRY SURFACE...LITTLE RAIN OVER THE LAST MONTH ACROSS MOST OF THE AREA. THE NAM IS THE ONLY MODEL SUGGESTING DEVELOPMENT...ALTHOUGH IT IS A LITTLE HIGH WITH CURRENT DEW PTS. THE RUC IS LESS FAVORABLE...BUT IS CLOSER BUT IS A DEGREE OR SO TO LOW WITH DEW PTS. THUS THE FORECAST DOES INCLUDE SOME PATCHY FOG IN THE PLATTE RIVER VALLEY...WHICH IS LIKELY THE FIRST PLACE FOR DEVELOPMENT ALTHOUGH CONFIDENCE IS LOW. HAVE ALSO INCLUDED SOME FOG ACROSS THE FAR NORTHWEST...HOWEVER THERE IS BETTER GROUND MOISTURE. TOMORROW COOL HIGH PRESSURE CENTERED OVER MINNESOTA...HOWEVER WILL SEE SOME COOLER TEMPS ALOFT /850 MB TEMPS AROUND 5C/ INTO THE HIGH PLAINS. WILL KEEP TEMPS ABOUT 5 TO 10 DEGREES COOLER THAN TODAY. LATELY THE WARMER MAV HAS BEEN CLOSER TO REALITY AND FAVORED THESE WARMER NUMBERS FOR TOMORROW. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 ...ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS FORECAST SUNDAY THROUGH FRIDAY... MID RANGE PERIODS (SATURDAY NIGHT THROUGH MONDAY)... THE UPPER TROUGH EXITING THE ROCKIES WILL MOVE ACROSS WESTERN NEBRASKA SATURDAY NIGHT INTO SUNDAY. WHILE MOISTURE WILL BE AMPLE FROM H7 TO H5...H85 TO H7 RELATIVELY DRY. CONCERN LIES IN SATURATED LAYER BELOW 875 MB. WITH WEAK OMEGA PRESENT ALONG WITH SUPERCOOLED DROPLETS OF -1C TO -3C...INTRODUCED PATCHY FREEZING FRIZZLE WHICH IS POSSIBLE FROM 09Z TO 15Z SUNDAY. SURFACE TEMPERATURES DURING THIS TIME SHOULD RANGE FROM 28 TO 32 DEGREES. THE AREA MAY AFFECT SOUTHEASTERN AREAS MAINLY EAST OF A CURTIS THROUGH CALLAWAY AND STUART LINE. OTHERWISE CLEARING SKIES FROM WEST TO EAST ON SUNDAY WITH ANOTHER NICE WARMUP. DOWNSLOPING WEST TO NORTHWEST WINDS 5 TO 15 MPH SHOULD PUSH HIGHS UP INTO THE LOWER TO MID 50S...EXCEPT COOLER UPPER 40S NEAR ONEILL AND BARTLETT. A WEAK COLD FRONT SUNDAY NIGHT. HIGHS MONDAY HOWEVER WILL REMAIN VERY SIMILAR TO SUNDAY. EXTENDED PERIODS (MONDAY NIGHT THROUGH FRIDAY)... THE MILD CONDITIONS WILL PERSIST IN THE EXTENDED PERIODS AS UPPER RIDGING DOMINATES THE CENTRAL CONUS. INCREASED TROUGHING ONTO THE WEST COAST WILL ALSO HELP TO AMPLIFY DOWNSTREAM RIDGE. UPPER RIDGING WILL BUILD INTO THE CENTRAL CONUS WEDNESDAY THROUGH FRIDAY WITH HIGHS IN THE 50S. SOME HIGHS IN THE WEST COULD EXCEED 60 DEGREES WEDNESDAY AND BEYOND. BY FRIDAY...A STRONG UPPER TROUGH WILL MOVE ONTO THE WEST COAST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 535 PM CST FRI DEC 5 2014 MAINLY CLEAR SKIES ARE EXPECTED TONIGHT ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. SOME PATCHY FOG IS POSSIBLE TOWARD SUNRISE SATURDAY IN THE PLATTE RIVER VALLEY. THIS MAY IMPACT THE KLBF TERMINAL WITH VISBYS DOWN TO 3SM. LOOK FOR HIGH CLOUDINESS TO INCREASE LATE SATURDAY MORNING...WITH BROKEN CIGS AROUND 25000 FT AGL EXPECTED DURING THE LATE AFTERNOON HOURS. WINDS WILL BE LIGHT AND VARIABLE AT UNDER 10 KTS TONIGHT...BECOMING SOUTH AND INCREASING TO 10 TO 15 KTS SATURDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MASEK SHORT TERM...MASEK LONG TERM...ROBERG AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1146 AM CST THU DEC 4 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CST THU DEC 4 2014 ITS BEEN ANOTHER NIGHT WITH QUIET CONDITIONS ACROSS THE REGION...WITH UPPER AIR AND SATELLITE DATA SHOWING ZONAL FLOW REMAINING IN PLACE ACROSS A GOOD CHUNK OF THE CONUS...AND NO NOTABLE DISTURBANCES IN THE AREA. OVER THE WEST COAST...SATELLITE IMAGERY SHOWS A COUPLE OF DISTURBANCES...ONE TO THE NORTH AND ANOTHER JUST MAKING ITS WAY ONTO THE FAR SRN PORTIONS. THAT SRN DISTURBANCE BEARS WATCHING THROUGH THE SHORT TERM PERIOD. UPPER LEVEL CIRRUS CONTINUES TO STREAM INTO THE AREA FROM THE WEST...CURRENTLY RESULTING IN PARTLY/MOSTLY CLOUDY SKIES TO THE SWRN CWA AND MOSTLY CLEAR SKIES TO THE NERN CWA. AT THE SURFACE...THE CWA REMAINS SET UP BETWEEN HIGH PRESSURE OVER THE MIDWEST REGION AND LOW PRESSURE DRAPED THROUGH THE HIGH PLAINS...KEEPING THE SRLY WINDS IN PLACE...SPEEDS ARE GENERALLY IN THE 5 TO 10 MPH RANGE. TEMPS AS OF 3 AM ARE MAINLY IN THE 20S...THOUGH A FEW LOWER 30S ARE IN PLACE ACROSS SWRN PORTIONS OF THE CWA. DURING THE DAYTIME HOURS TODAY...OVERALL THERE WERENT ANY NOTABLE CHANGES MADE TO THE FORECAST...WHICH REMAINS DRY. MODELS ARE IN GOOD AGREEMENT SHOWING LITTLE CHANGE WITH THE UPPER LEVEL PATTERN...THOUGH THAT ABOVE MENTIONED SWRN COAST DISTURBANCE CONTINUES TO MAKE ITS WAY EAST...BY 00Z THIS EVENING IT LOOKS TO HAVE PUSHED JUST EAST OF THE 4 CORNERS REGION. SAME GOES FOR THE SFC PATTERN...LITTLE CHANGE...AND THOSE SRLY WINDS CONTINUE...TOPPING OUT AROUND 10 MPH. STILL LOOKING AT A BUMP UP IN TEMPERATURES TODAY...WITH MODELS REMAINING IN GOOD AGREEMENT SHOWING WARMER AIR ALOFT BUILDING IN FROM THE WEST. DID BUMP UP HIGHS A TOUCH...WITH MID 40S EAST TO LOWER 50S WEST. NOT QUITE AS HIGH AS THE RAP SUGGESTS...SO THAT WILL BE SOMETHING FOR THE DAY CREW TO MONITOR...SEE HOW THIS MORNING TEMPS ARE TRENDING. TONIGHT...THE MAIN CHANGE MADE TO THE FORECAST WAS TO RAISE POPS ACROSS THE SRN CWA /MAINLY OUR KS COUNTIES/. LATEST MODEL RUNS ARE IN PRETTY GOOD AGREEMENT SHOWING THAT UPPER LEVEL DISTURBANCE CONTINUING TO MAKE ITS WAY TO THE EAST...CROSSING PRIMARILY OVER KS DURING THE OVERNIGHT HOURS. CONTINUING TO KEEP THE EARLY EVENING HOURS DRY...WITH PRECIPITATION CHANCES STARTING TO CREEP FURTHER NORTH INTO OUR FAR SOUTH AS WE GET TOWARD MIDNIGHT. AT THIS POINT THE BEST CHANCES LOOK TO COME BETWEEN 06-12Z...AND BUMPED UP POPS ACROSS NC KS INTO THE 30-70 PERCENT RANGE. HAVE SOME 20-30 POPS AFFECTING THE FAR SRN ROW OF NEB COUNTIES AS WELL. WILL HAVE TO SEE HOW THE 12Z RUN OF MODELS TREND...THE 06Z NAM SUGGESTS POPS NEED TO BE EXPANDED FURTHER NORTH. THANKFULLY...STILL LOOKING FOR THIS TO BE AN ALL LIQUID EVENT. THOUGH TEMPS WILL BE FALLING THROUGH THE EVENING HOURS...EXPECTING THAT AS THE INCREASED CLOUD COVER/PRECIP MOVES INTO THE AREA...TEMPS SHOULD LEVEL OUT/IF NOT RISE A FEW DEGREES...AND EXPECTING A COLD RAIN WITH TEMPS IN THE MID 30S...THOUGH UPPER 30S/NEAR 40 NOT OUT OF THE QUESTION. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 349 AM CST THU DEC 4 2014 THE EXTENDED PERIODS WILL SEE SOME CHCS FOR PCPN EARLY ON...WHILE TEMPERATURES REMAIN ON THE MILD SIDE. RAIN (NOT SNOW!) WHICH DEVELOPS OVERNIGHT TONIGHT IS EXPECTED TO BE ONGOING BUT WINDING DOWN ACROSS OUR SOUTHEAST CWA FRIDAY MORNING AS A CLOSED H7 LOW ACROSS NORTHERN KS FILLS AND TRANSLATES EASTWARD. PRECIPITATION CHCS END ACROSS OUR SOUTHERN ZONES W/E AS THE TROUGH AXIS PASSES DURING THE MORNING. HAVE MAINTAINED FOG POTENTIAL FOR THE FIRST PART OF THE DAY IN THE PRESENCE OF LOW CLOUDS/LLVL MOISTURE UNTIL THE SFC COLD FRONTAL BOUNDARY MOVES THRU DURING THE MORNING...SCOURING THE LLVL MOISTURE. EXPECT THE COLD AIR ADVECTION BEHIND THE FRONT TO BE OFFSET BY THE INCREASE IN INSOLATION AND HAVE ONLY MADE MINOR ADJUSTMENTS TO HIGHS. A STRONG SFC HIGH PRESSURE SYSTEM BUILDS SOUTH FROM THE DAKOTAS ONTO THE PLAINS BEHIND THE COLD FRONT FRIDAY/FRIDAY NIGHT...WHICH WILL RESULT IN A CHILLY NIGHT WITH LOWS IN THE TEENS/20S. THE CENTER OF THE SFC HIGH MOVES INTO MN DURING THE DAY ON SATURDAY WITH RETURN FLOW OF EAST/SOUTHEASTERLY WINDS SETTING UP ACROSS OUR REGION. THE LLVL MOISTURE/STRATUS IS PROGGED TO MIGRATE WESTWARD IN THE EASTERLY LLVL FLOW. 00Z MODELS SUGGESTED THE LOW CLOUDS COULD REACH OUR EASTERN ZONES DURING THE DAY AND EFFECTIVELY STALL TEMPS...BUT 06Z TRENDS KEEP THE BRUNT OF THIS JUST TO OUR EAST. BY SATURDAY NIGHT THE CLOUD COVER THICKENS AHEAD OF A SHORTWAVE TROUGH MOVING EAST OF THE ROCKIES AND ONTO THE PLAINS. ISENTROPIC LIFT INCREASES AHEAD OF THIS SYSTEM AND WE COULD SEE SOME LIGHT PCPN DEVELOPING WITH MODEL FORECAST SOUNDINGS THE POTENTIAL FOR FREEZING DRIZZLE INITIALLY UNTIL LLVL TEMPS RISE. CONFIDENCE IS NOT HIGH ENOUGH TO MENTION FREEZING PCPN THIS FAR OUT AND HAVE WENT WITH SILENT POPS FOR NOW. THE EXTENDED INIT REINTRODUCED POPS INTO THE SUNDAY TIME FRAME AS THE SYSTEM MOVES THRU...WHICH FAVORS A LIQUID EVENT DURING THE DAYTIME HOURS. THE FORECAST DRIES OUT SUNDAY NIGHT BEHIND THE DEPARTING TROUGH AND REMAINS DRY THRU WEDNESDAY. A CLIPPER SYSTEM/TROUGH MOVING THRU THE UPPER MIDWEST/GREAT LAKES REGION WILL BACK IN SOME SLIGHTLY COOLER AIR INTO OUR NORTHEAST ZONES HEADING INTO MONDAY. A DRY AND MILD AIRMASS NEXT WEEK WILL RESULT IN ABOVE NORMAL TEMPS THRU WEDNESDAY WITH HIGHS AVERAGING IN THE 40S/50. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1146 AM CST THU DEC 4 2014 VFR CONDITIONS CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS. CLOUD COVER WILL PERSIST THROUGH THE TAF PERIOD...BUT FOR THE MOST PART NOTHING BELOW 15000FT AGL SHOULD BE OBSERVED. THAT SAID...THERE IS ONE SET OF GUIDANCE WHICH SUGGESTS A BRIEF PERIOD OF MVFR TO IFR CEILING COULD BE REALIZED FRIDAY MORNING AFTER SUNRISE. HOWEVER...CONFIDENCE IS TOO LOW TO INTRODUCE ANY SUCH CEILING IN EITHER TAF...BUT STILL SOMETHING TO MONITOR THROUGH THE NEXT 24 HOURS. PRECIPITATION WILL LIKELY SPREAD INTO KANSAS AND SOUTH/SOUTHEASTERN NEBRASKA TONIGHT INTO FRIDAY MORNING...BUT AT THIS TIME ANY PRECIPITATION IS EXPECTED TO REMAIN SOUTHEAST OF KEAR AND KGRI. THE SURFACE WIND WILL REMAIN FAIRLY LIGHT FROM THE SOUTH...SUSTAINED AT AROUND 10KTS...THROUGH MUCH OF THE TAF PERIOD BEFORE BECOMING VARIABLE AFTER 12Z FRIDAY. VISIBILITY RESTRICTION IS NOT CURRENTLY EXPECTED AT EITHER TAF SITE THROUGH THE NEXT 24 HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...FAY AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
532 AM CST THU DEC 4 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CST THU DEC 4 2014 ITS BEEN ANOTHER NIGHT WITH QUIET CONDITIONS ACROSS THE REGION...WITH UPPER AIR AND SATELLITE DATA SHOWING ZONAL FLOW REMAINING IN PLACE ACROSS A GOOD CHUNK OF THE CONUS...AND NO NOTABLE DISTURBANCES IN THE AREA. OVER THE WEST COAST...SATELLITE IMAGERY SHOWS A COUPLE OF DISTURBANCES...ONE TO THE NORTH AND ANOTHER JUST MAKING ITS WAY ONTO THE FAR SRN PORTIONS. THAT SRN DISTURBANCE BEARS WATCHING THROUGH THE SHORT TERM PERIOD. UPPER LEVEL CIRRUS CONTINUES TO STREAM INTO THE AREA FROM THE WEST...CURRENTLY RESULTING IN PARTLY/MOSTLY CLOUDY SKIES TO THE SWRN CWA AND MOSTLY CLEAR SKIES TO THE NERN CWA. AT THE SURFACE...THE CWA REMAINS SET UP BETWEEN HIGH PRESSURE OVER THE MIDWEST REGION AND LOW PRESSURE DRAPED THROUGH THE HIGH PLAINS...KEEPING THE SRLY WINDS IN PLACE...SPEEDS ARE GENERALLY IN THE 5 TO 10 MPH RANGE. TEMPS AS OF 3 AM ARE MAINLY IN THE 20S...THOUGH A FEW LOWER 30S ARE IN PLACE ACROSS SWRN PORTIONS OF THE CWA. DURING THE DAYTIME HOURS TODAY...OVERALL THERE WERENT ANY NOTABLE CHANGES MADE TO THE FORECAST...WHICH REMAINS DRY. MODELS ARE IN GOOD AGREEMENT SHOWING LITTLE CHANGE WITH THE UPPER LEVEL PATTERN...THOUGH THAT ABOVE MENTIONED SWRN COAST DISTURBANCE CONTINUES TO MAKE ITS WAY EAST...BY 00Z THIS EVENING IT LOOKS TO HAVE PUSHED JUST EAST OF THE 4 CORNERS REGION. SAME GOES FOR THE SFC PATTERN...LITTLE CHANGE...AND THOSE SRLY WINDS CONTINUE...TOPPING OUT AROUND 10 MPH. STILL LOOKING AT A BUMP UP IN TEMPERATURES TODAY...WITH MODELS REMAINING IN GOOD AGREEMENT SHOWING WARMER AIR ALOFT BUILDING IN FROM THE WEST. DID BUMP UP HIGHS A TOUCH...WITH MID 40S EAST TO LOWER 50S WEST. NOT QUITE AS HIGH AS THE RAP SUGGESTS...SO THAT WILL BE SOMETHING FOR THE DAY CREW TO MONITOR...SEE HOW THIS MORNING TEMPS ARE TRENDING. TONIGHT...THE MAIN CHANGE MADE TO THE FORECAST WAS TO RAISE POPS ACROSS THE SRN CWA /MAINLY OUR KS COUNTIES/. LATEST MODEL RUNS ARE IN PRETTY GOOD AGREEMENT SHOWING THAT UPPER LEVEL DISTURBANCE CONTINUING TO MAKE ITS WAY TO THE EAST...CROSSING PRIMARILY OVER KS DURING THE OVERNIGHT HOURS. CONTINUING TO KEEP THE EARLY EVENING HOURS DRY...WITH PRECIPITATION CHANCES STARTING TO CREEP FURTHER NORTH INTO OUR FAR SOUTH AS WE GET TOWARD MIDNIGHT. AT THIS POINT THE BEST CHANCES LOOK TO COME BETWEEN 06-12Z...AND BUMPED UP POPS ACROSS NC KS INTO THE 30-70 PERCENT RANGE. HAVE SOME 20-30 POPS AFFECTING THE FAR SRN ROW OF NEB COUNTIES AS WELL. WILL HAVE TO SEE HOW THE 12Z RUN OF MODELS TREND...THE 06Z NAM SUGGESTS POPS NEED TO BE EXPANDED FURTHER NORTH. THANKFULLY...STILL LOOKING FOR THIS TO BE AN ALL LIQUID EVENT. THOUGH TEMPS WILL BE FALLING THROUGH THE EVENING HOURS...EXPECTING THAT AS THE INCREASED CLOUD COVER/PRECIP MOVES INTO THE AREA...TEMPS SHOULD LEVEL OUT/IF NOT RISE A FEW DEGREES...AND EXPECTING A COLD RAIN WITH TEMPS IN THE MID 30S...THOUGH UPPER 30S/NEAR 40 NOT OUT OF THE QUESTION. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 349 AM CST THU DEC 4 2014 THE EXTENDED PERIODS WILL SEE SOME CHCS FOR PCPN EARLY ON...WHILE TEMPERATURES REMAIN ON THE MILD SIDE. RAIN (NOT SNOW!) WHICH DEVELOPS OVERNIGHT TONIGHT IS EXPECTED TO BE ONGOING BUT WINDING DOWN ACROSS OUR SOUTHEAST CWA FRIDAY MORNING AS A CLOSED H7 LOW ACROSS NORTHERN KS FILLS AND TRANSLATES EASTWARD. PRECIPITATION CHCS END ACROSS OUR SOUTHERN ZONES W/E AS THE TROUGH AXIS PASSES DURING THE MORNING. HAVE MAINTAINED FOG POTENTIAL FOR THE FIRST PART OF THE DAY IN THE PRESENCE OF LOW CLOUDS/LLVL MOISTURE UNTIL THE SFC COLD FRONTAL BOUNDARY MOVES THRU DURING THE MORNING...SCOURING THE LLVL MOISTURE. EXPECT THE COLD AIR ADVECTION BEHIND THE FRONT TO BE OFFSET BY THE INCREASE IN INSOLATION AND HAVE ONLY MADE MINOR ADJUSTMENTS TO HIGHS. A STRONG SFC HIGH PRESSURE SYSTEM BUILDS SOUTH FROM THE DAKOTAS ONTO THE PLAINS BEHIND THE COLD FRONT FRIDAY/FRIDAY NIGHT...WHICH WILL RESULT IN A CHILLY NIGHT WITH LOWS IN THE TEENS/20S. THE CENTER OF THE SFC HIGH MOVES INTO MN DURING THE DAY ON SATURDAY WITH RETURN FLOW OF EAST/SOUTHEASTERLY WINDS SETTING UP ACROSS OUR REGION. THE LLVL MOISTURE/STRATUS IS PROGGED TO MIGRATE WESTWARD IN THE EASTERLY LLVL FLOW. 00Z MODELS SUGGESTED THE LOW CLOUDS COULD REACH OUR EASTERN ZONES DURING THE DAY AND EFFECTIVELY STALL TEMPS...BUT 06Z TRENDS KEEP THE BRUNT OF THIS JUST TO OUR EAST. BY SATURDAY NIGHT THE CLOUD COVER THICKENS AHEAD OF A SHORTWAVE TROUGH MOVING EAST OF THE ROCKIES AND ONTO THE PLAINS. ISENTROPIC LIFT INCREASES AHEAD OF THIS SYSTEM AND WE COULD SEE SOME LIGHT PCPN DEVELOPING WITH MODEL FORECAST SOUNDINGS THE POTENTIAL FOR FREEZING DRIZZLE INITIALLY UNTIL LLVL TEMPS RISE. CONFIDENCE IS NOT HIGH ENOUGH TO MENTION FREEZING PCPN THIS FAR OUT AND HAVE WENT WITH SILENT POPS FOR NOW. THE EXTENDED INIT REINTRODUCED POPS INTO THE SUNDAY TIME FRAME AS THE SYSTEM MOVES THRU...WHICH FAVORS A LIQUID EVENT DURING THE DAYTIME HOURS. THE FORECAST DRIES OUT SUNDAY NIGHT BEHIND THE DEPARTING TROUGH AND REMAINS DRY THRU WEDNESDAY. A CLIPPER SYSTEM/TROUGH MOVING THRU THE UPPER MIDWEST/GREAT LAKES REGION WILL BACK IN SOME SLIGHTLY COOLER AIR INTO OUR NORTHEAST ZONES HEADING INTO MONDAY. A DRY AND MILD AIRMASS NEXT WEEK WILL RESULT IN ABOVE NORMAL TEMPS THRU WEDNESDAY WITH HIGHS AVERAGING IN THE 40S/50. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 525 AM CST THU DEC 4 2014 QUIET WEATHER AND VFR CONDITIONS CONTINUE IN THE FORECAST FOR THIS TAF PERIOD...THOUGH WILL HAVE TO WATCH THE OVERNIGHT HOURS FOR A DISTURBANCE MOVING ONTO THE PLAINS. THIS DISTURBANCE IS GOING TO BRING RAIN CHANCES TO THE REGION...BUT AT THIS POINT THE BETTER CHANCES LOOK TO REMAIN JUST OFF TO THE SOUTH OF THE TERMINAL AREAS. EXPECTING CLOUD COVER THROUGH THE PERIOD TO BE CONFINED TO THE MID/UPPER LEVELS...AND THOUGH THERE IS THE POTENTIAL FOR SOME PATCHY FOG TO DEVELOP TONIGHT...THINKING THAT AGAIN THE TERMINALS WOULD BE ON THE EDGE OF THE MAIN AREA...SO CONFIDENCE AT THIS TIME IS NOT HIGH ENOUGH TO INSERT A MENTION IN THE TAF. REALLY NOT LOOKING AT A SIGNIFICANT CHANGE IN WINDS THROUGH THE PERIOD...REMAINING S/SWRLY WITH SPEEDS TOPPING OUT AROUND 10 MPH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...FAY AVIATION...ADP
AREA FORECAST DISCUSSION
NWS HASTINGS NE
351 AM CST THU DEC 4 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CST THU DEC 4 2014 ITS BEEN ANOTHER NIGHT WITH QUIET CONDITIONS ACROSS THE REGION...WITH UPPER AIR AND SATELLITE DATA SHOWING ZONAL FLOW REMAINING IN PLACE ACROSS A GOOD CHUNK OF THE CONUS...AND NO NOTABLE DISTURBANCES IN THE AREA. OVER THE WEST COAST...SATELLITE IMAGERY SHOWS A COUPLE OF DISTURBANCES...ONE TO THE NORTH AND ANOTHER JUST MAKING ITS WAY ONTO THE FAR SRN PORTIONS. THAT SRN DISTURBANCE BEARS WATCHING THROUGH THE SHORT TERM PERIOD. UPPER LEVEL CIRRUS CONTINUES TO STREAM INTO THE AREA FROM THE WEST...CURRENTLY RESULTING IN PARTLY/MOSTLY CLOUDY SKIES TO THE SWRN CWA AND MOSTLY CLEAR SKIES TO THE NERN CWA. AT THE SURFACE...THE CWA REMAINS SET UP BETWEEN HIGH PRESSURE OVER THE MIDWEST REGION AND LOW PRESSURE DRAPED THROUGH THE HIGH PLAINS...KEEPING THE SRLY WINDS IN PLACE...SPEEDS ARE GENERALLY IN THE 5 TO 10 MPH RANGE. TEMPS AS OF 3 AM ARE MAINLY IN THE 20S...THOUGH A FEW LOWER 30S ARE IN PLACE ACROSS SWRN PORTIONS OF THE CWA. DURING THE DAYTIME HOURS TODAY...OVERALL THERE WERENT ANY NOTABLE CHANGES MADE TO THE FORECAST...WHICH REMAINS DRY. MODELS ARE IN GOOD AGREEMENT SHOWING LITTLE CHANGE WITH THE UPPER LEVEL PATTERN...THOUGH THAT ABOVE MENTIONED SWRN COAST DISTURBANCE CONTINUES TO MAKE ITS WAY EAST...BY 00Z THIS EVENING IT LOOKS TO HAVE PUSHED JUST EAST OF THE 4 CORNERS REGION. SAME GOES FOR THE SFC PATTERN...LITTLE CHANGE...AND THOSE SRLY WINDS CONTINUE...TOPPING OUT AROUND 10 MPH. STILL LOOKING AT A BUMP UP IN TEMPERATURES TODAY...WITH MODELS REMAINING IN GOOD AGREEMENT SHOWING WARMER AIR ALOFT BUILDING IN FROM THE WEST. DID BUMP UP HIGHS A TOUCH...WITH MID 40S EAST TO LOWER 50S WEST. NOT QUITE AS HIGH AS THE RAP SUGGESTS...SO THAT WILL BE SOMETHING FOR THE DAY CREW TO MONITOR...SEE HOW THIS MORNING TEMPS ARE TRENDING. TONIGHT...THE MAIN CHANGE MADE TO THE FORECAST WAS TO RAISE POPS ACROSS THE SRN CWA /MAINLY OUR KS COUNTIES/. LATEST MODEL RUNS ARE IN PRETTY GOOD AGREEMENT SHOWING THAT UPPER LEVEL DISTURBANCE CONTINUING TO MAKE ITS WAY TO THE EAST...CROSSING PRIMARILY OVER KS DURING THE OVERNIGHT HOURS. CONTINUING TO KEEP THE EARLY EVENING HOURS DRY...WITH PRECIPITATION CHANCES STARTING TO CREEP FURTHER NORTH INTO OUR FAR SOUTH AS WE GET TOWARD MIDNIGHT. AT THIS POINT THE BEST CHANCES LOOK TO COME BETWEEN 06-12Z...AND BUMPED UP POPS ACROSS NC KS INTO THE 30-70 PERCENT RANGE. HAVE SOME 20-30 POPS AFFECTING THE FAR SRN ROW OF NEB COUNTIES AS WELL. WILL HAVE TO SEE HOW THE 12Z RUN OF MODELS TREND...THE 06Z NAM SUGGESTS POPS NEED TO BE EXPANDED FURTHER NORTH. THANKFULLY...STILL LOOKING FOR THIS TO BE AN ALL LIQUID EVENT. THOUGH TEMPS WILL BE FALLING THROUGH THE EVENING HOURS...EXPECTING THAT AS THE INCREASED CLOUD COVER/PRECIP MOVES INTO THE AREA...TEMPS SHOULD LEVEL OUT/IF NOT RISE A FEW DEGREES...AND EXPECTING A COLD RAIN WITH TEMPS IN THE MID 30S...THOUGH UPPER 30S/NEAR 40 NOT OUT OF THE QUESTION. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 349 AM CST THU DEC 4 2014 THE EXTENDED PERIODS WILL SEE SOME CHCS FOR PCPN EARLY ON...WHILE TEMPERATURES REMAIN ON THE MILD SIDE. RAIN (NOT SNOW!) WHICH DEVELOPS OVERNIGHT TONIGHT IS EXPECTED TO BE ONGOING BUT WINDING DOWN ACROSS OUR SOUTHEAST CWA FRIDAY MORNING AS A CLOSED H7 LOW ACROSS NORTHERN KS FILLS AND TRANSLATES EASTWARD. PRECIPITATION CHCS END ACROSS OUR SOUTHERN ZONES W/E AS THE TROUGH AXIS PASSES DURING THE MORNING. HAVE MAINTAINED FOG POTENTIAL FOR THE FIRST PART OF THE DAY IN THE PRESENCE OF LOW CLOUDS/LLVL MOISTURE UNTIL THE SFC COLD FRONTAL BOUNDARY MOVES THRU DURING THE MORNING...SCOURING THE LLVL MOISTURE. EXPECT THE COLD AIR ADVECTION BEHIND THE FRONT TO BE OFFSET BY THE INCREASE IN INSOLATION AND HAVE ONLY MADE MINOR ADJUSTMENTS TO HIGHS. A STRONG SFC HIGH PRESSURE SYSTEM BUILDS SOUTH FROM THE DAKOTAS ONTO THE PLAINS BEHIND THE COLD FRONT FRIDAY/FRIDAY NIGHT...WHICH WILL RESULT IN A CHILLY NIGHT WITH LOWS IN THE TEENS/20S. THE CENTER OF THE SFC HIGH MOVES INTO MN DURING THE DAY ON SATURDAY WITH RETURN FLOW OF EAST/SOUTHEASTERLY WINDS SETTING UP ACROSS OUR REGION. THE LLVL MOISTURE/STRATUS IS PROGGED TO MIGRATE WESTWARD IN THE EASTERLY LLVL FLOW. 00Z MODELS SUGGESTED THE LOW CLOUDS COULD REACH OUR EASTERN ZONES DURING THE DAY AND EFFECTIVELY STALL TEMPS...BUT 06Z TRENDS KEEP THE BRUNT OF THIS JUST TO OUR EAST. BY SATURDAY NIGHT THE CLOUD COVER THICKENS AHEAD OF A SHORTWAVE TROUGH MOVING EAST OF THE ROCKIES AND ONTO THE PLAINS. ISENTROPIC LIFT INCREASES AHEAD OF THIS SYSTEM AND WE COULD SEE SOME LIGHT PCPN DEVELOPING WITH MODEL FORECAST SOUNDINGS THE POTENTIAL FOR FREEZING DRIZZLE INITIALLY UNTIL LLVL TEMPS RISE. CONFIDENCE IS NOT HIGH ENOUGH TO MENTION FREEZING PCPN THIS FAR OUT AND HAVE WENT WITH SILENT POPS FOR NOW. THE EXTENDED INIT REINTRODUCED POPS INTO THE SUNDAY TIME FRAME AS THE SYSTEM MOVES THRU...WHICH FAVORS A LIQUID EVENT DURING THE DAYTIME HOURS. THE FORECAST DRIES OUT SUNDAY NIGHT BEHIND THE DEPARTING TROUGH AND REMAINS DRY THRU WEDNESDAY. A CLIPPER SYSTEM/TROUGH MOVING THRU THE UPPER MIDWEST/GREAT LAKES REGION WILL BACK IN SOME SLIGHTLY COOLER AIR INTO OUR NORTHEAST ZONES HEADING INTO MONDAY. A DRY AND MILD AIRMASS NEXT WEEK WILL RESULT IN ABOVE NORMAL TEMPS THRU WEDNESDAY WITH HIGHS AVERAGING IN THE 40S/50. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1127 PM CST WED DEC 3 2014 QUIET WEATHER WITH VFR CONDITIONS CURRENTLY FORECAST FOR THIS TAF PERIOD. ANY CLOUDS THAT PASS THROUGH THE TERMINAL AREAS LOOKING TO REMAIN IN THE UPPER LEVELS. NOT EXPECTING ANY SIGNIFICANT CHANGES IN WINDS THROUGH THE PERIOD WITH LITTLE CHANGE IN THE PATTERN...WITH WINDS REMAINING SOUTHERLY AND SPEEDS TOPPING OUT AROUND 10 MPH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...FAY AVIATION...ADP
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
322 PM MST THU DEC 4 2014 .SYNOPSIS... WET WEATHER WILL CONTINUE INTO THIS EVENING FOR MUCH OF THE REGION BEFORE SLOW CLEARING DEVELOPS OVERNIGHT. SNOW ACCUMULATIONS WILL BE GENERALLY LIGHT AND CONFINED TO AREAS ABOVE 9000 FEET. HIGH PRESSURE WILL RETURN TO THE AREA BRIEFLY ON FRIDAY. THE NEXT STORM SYSTEM WILL MOVE IN SATURDAY WITH THICK CLOUD COVER AND SHOWERS. SNOW LEVELS WILL BE LOWER WITH THE NEXT SYSTEM HOWEVER AMOUNTS WILL STILL BE LIGHT. SLIGHTLY ACTIVE WEATHER IS EXPECTED THROUGH NEXT WEEK WITH AT LEAST SOME CHANCES FOR SHOWERS...PARTICULARLY IN THE HIGHER TERRAIN. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH MUCH OF NEXT WEEK. && .DISCUSSION... LATEST RADAR LOOP THIS AFTERNOON SHOWING THE MOST WIDESPREAD PRECIP ON SCOPE IN QUITE SOME TIME. THE AXIS OF THE UPPER WAVE PER SATELLITE IMAGERY IS STILL POISED ALONG THE NM/AZ BORDER...AND MOVING QUICKLY EAST. THE 18Z HRRR AND NAM AGREE PRECIP WILL SLOWLY TAPER OFF DURING THE MID/LATE EVENING HOURS MOST AREAS...AND LINGER ALONG WEST SLOPES OF THE NORTHERN HIGH TERRAIN. CURRENTLY SNOW LEVELS ARE IMPRESSIVELY HIGH WITH TEMPS NEAR FREEZING STILL AROUND 11KFT. COLD ADVECTION WITH THE APPROACHING TROUGH AXIS WILL LOWER SNOW LEVELS TO 9KFT THIS EVENING THEN ABOUT 8KFT BY SUNRISE. THAT TREND IS ALSO REFLECTED IN THE MIN TEMP FORECAST WHICH RUNS ABOUT 5-15F ABOVE NORMAL. WEAK RIDGING NOTED BEHIND THIS SYSTEM ALREADY ON WATER VAPOR IMAGERY WILL BE SHORT-LIVED AS THE NEXT STREAM OF THICK HIGH CLOUDS IS ON THE MOVE OVER THE EASTERN PACIFIC. INCREASED CLOUD COVER AND POPS SLIGHTLY FOR SATURDAY/SATURDAY NIGHT. QPF WITH THIS SYSTEM IS PROGGED MUCH LOWER THAN THIS CURRENT SYSTEM AND THE SOURCE REGION OF MID/ UPPER LEVEL MOISTURE IS NOT SO MUCH SUBTROPICAL...BUT STILL WOULD NOT BE SURPRISED FOR MODELS TO CONTINUE TRENDING DEEPER AND WETTER. NONETHELESS...PRECIP MODE LOOKS MORE CONVECTIVE THAN STRATIFORM. 700MB COLD ADVECTION WILL BE SLIGHTLY BETTER AND THICKNESS VALUES DECREASE BUT STILL SNOW LEVELS WILL BE PRETTY HIGH FOR DECEMBER. LOCATIONS ABOVE 8KFT COULD SEE A FEW INCHES OF SNOW...WITH QPF ON THE ORDER OF 0.10-0.20 FOR LOWER ELEVATIONS. ASSOCIATED PWAT VALES FROM THE NAM AND GFS AT KABQ NEAR 0.50 INCHES. ANOTHER BREAK IN THE ACTION IS ON TAP FOR SUNDAY HOWEVER IT STILL LOOKS LIKE HIGH LEVEL MOISTURE WILL KEEP HIGH CLOUDS AROUND. SEVERAL WEATHER DISTURBANCES ARE ADVERTISED THROUGH NEXT WEEK BUT TIMING AND STRENGTH ARE IN QUESTION. THERE ARE AT LEAST SLIGHT CHANCES WITH RETURN FLOW FROM THE CENTRAL MT CHAIN EASTWARD. THE GFS AND ECMWF ARE STILL SHOWING A BIG STORM SYSTEM LATE NEXT WEEK. GUYER && .FIRE WEATHER... WET WEATHER SYSTEM WILL EJECT EASTWARD TONIGHT LEAVING SEVERAL INCHES OF SNOW ACCUMULATION MAINLY ABOVE 8000 FT IN THE NORTHERN MOUNTAINS. MIN HUMIDITIES ON FRIDAY WILL FALL 14 TO 30 DEGREES AS A WEAK RIDGE OF HIGH PRESSURE CROSSES FROM THE WEST. THERE WILL ALSO BE WIDESPREAD POOR VENTILATION ON FRIDAY WEST OF THE EASTERN TIER OF COUNTIES AS TEMPERATURES RISE A FEW TO 5 DEGREES IN MOST PLACES. ANOTHER UPPER LEVEL TROUGH WILL CROSS FROM THE WEST WITH WIDESPREAD PRECIPITATION SATURDAY AND SATURDAY NIGHT. AT THIS TIME SOUTHERN...CENTRAL AND NORTHWEST AREAS LOOK FAVORED FOR WETTING PRECIPITATION WITH SPOTTIER AND LIGHTER PRECIP ACROSS THE NORTHEAST. IT SHOULD BE ANOTHER WARM SYSTEM WITH 700 MB TEMPERATURES ONLY DROPPING TO BETWEEN 0 AND 2 DEGREES. THE NORTHERN MOUNTAINS SHOULD ACCUMULATE A FEW TO SEVERAL INCHES OF SNOW ABOVE 9000 FT AGAIN...WITH THE HIGHER AMOUNTS ON WEST FACING SLOPES. THERE WILL BE VENTILATION IMPROVEMENT IN MOST PLACES SATURDAY...BUT POCKETS OF POOR VENTILATION WILL PERSIST MAINLY ACROSS EAST CENTRAL AND NORTHWEST AREAS. TEMPERATURES WILL TREND DOWNWARD AGAIN IN MOST PLACES SATURDAY. ANOTHER RIDGE OF HIGH PRESSURE WILL CROSS ALOFT SUNDAY BEFORE THE FLOW TURNS ZONAL ON MONDAY. THIS WILL RESULT IN A TWO DAY WARMING AND DRYING TREND IN MOST PLACES WITH WIDESPREAD POOR VENTILATION BOTH DAYS. THERE SHOULD BE POCKETS OF FAIR TO GOOD VENTILATION EAST OF THE CENTRAL MOUNTAINS. MODELS ARE IN FAIR AGREEMENT ON A WEAKER UPPER LEVEL TROUGH CROSSING TUESDAY BEFORE A RIDGE ON WEDNESDAY. TUESDAYS TROUGH COULD TRIGGER A FEW LIGHT SHOWERS OVER THE MOUNTAINS AND SE AREAS. AFTER SOME VENTILATION IMPROVEMENT WITHIN 50 MILES OF THE I-40 CORRIDOR TUESDAY...WIDESPREAD POOR VENTILATION IS EXPECTED AGAIN ON WEDNESDAY. HIGH TEMPERATURES WILL ALSO FALL A FEW DEGREES THEN REBOUND WEDNESDAY. 44 && .AVIATION... 18Z TAF CYCLE A WAVE OF PRECIPITATION WILL PASS NEWD OVER THE AREA TODAY WITH MVFR AND IFR CONDITIONS IN LIGHT RAIN AND HIGH TERRAIN SNOW COMMON. ABUNDANT MT OBSCURATION IS ALSO EXPECTED AREAWIDE. THE BEST FETCH OF MOISTURE SHOULD PASS N AND W OF KROW...BUT EVEN THEY COULD BRIEFLY EXPERIENCE SOME HIGH BASED SHOWERS THIS AFTN. THE SNOW LEVEL SHOULD DROP FROM AROUND 9K FT ACROSS THE N AND 10K FT ACROSS THE S TODAY TO AROUND 7500 FT THIS EVENING. THE WAVE OF PCPN IS PROGGED TO EXIT W CENTRAL AND SW AREAS LATE THIS AFTN...CENTRAL AREAS EARLY THIS EVENING AND E AREAS DURING THE MID TO LATE EVENING. A SECONDARY BATCH OF SHOWERS ACROSS NW AND N CENTRAL AREAS TODAY SHOULD LINGER WELL INTO THE EVENING. CEILINGS ARE LIKELY TO RISE TO VFR THIS EVENING ACROSS CENTRAL AREAS. LOW CLOUDS AND/OR PATCHY FOG SHOULD THEN DEVELOP ACROSS CENTRAL AND WESTERN AREAS LATE TONIGHT INTO FRI MORNING. 44 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 34 51 33 53 / 40 5 5 20 DULCE........................... 29 50 24 52 / 70 5 5 30 CUBA............................ 32 50 28 49 / 70 5 5 30 GALLUP.......................... 33 52 31 54 / 30 5 5 30 EL MORRO........................ 31 50 29 50 / 30 5 5 30 GRANTS.......................... 31 52 26 52 / 30 0 5 20 QUEMADO......................... 34 51 35 51 / 30 0 0 30 GLENWOOD........................ 36 63 36 61 / 20 0 0 20 CHAMA........................... 26 48 23 48 / 80 10 5 30 LOS ALAMOS...................... 34 47 35 46 / 60 0 5 20 PECOS........................... 34 50 32 45 / 60 0 5 20 CERRO/QUESTA.................... 25 46 23 46 / 70 5 5 20 RED RIVER....................... 25 40 20 40 / 100 10 5 20 ANGEL FIRE...................... 23 45 21 44 / 80 10 5 20 TAOS............................ 29 48 26 47 / 80 0 5 20 MORA............................ 33 51 32 46 / 60 0 5 20 ESPANOLA........................ 33 52 30 52 / 60 0 5 10 SANTA FE........................ 34 47 34 47 / 70 0 5 20 SANTA FE AIRPORT................ 33 52 29 51 / 60 0 5 20 ALBUQUERQUE FOOTHILLS........... 36 52 39 52 / 60 0 5 20 ALBUQUERQUE HEIGHTS............. 39 55 36 55 / 60 0 5 10 ALBUQUERQUE VALLEY.............. 36 56 34 56 / 50 0 5 10 ALBUQUERQUE WEST MESA........... 37 56 34 56 / 60 0 5 10 LOS LUNAS....................... 36 56 30 55 / 50 0 0 10 RIO RANCHO...................... 38 55 36 55 / 60 0 5 20 SOCORRO......................... 37 59 34 58 / 30 0 0 10 SANDIA PARK/CEDAR CREST......... 33 50 33 50 / 60 0 5 30 TIJERAS......................... 34 52 35 52 / 60 0 5 20 MORIARTY/ESTANCIA............... 30 54 25 51 / 50 0 5 20 CLINES CORNERS.................. 33 53 30 47 / 50 0 5 20 GRAN QUIVIRA.................... 36 54 34 52 / 40 0 0 20 CARRIZOZO....................... 37 58 34 56 / 30 0 0 10 RUIDOSO......................... 36 59 32 55 / 20 0 0 20 CAPULIN......................... 35 51 30 47 / 70 0 5 5 RATON........................... 32 54 28 48 / 60 0 5 5 SPRINGER........................ 32 56 29 49 / 60 0 5 10 LAS VEGAS....................... 33 55 28 47 / 50 0 5 10 CLAYTON......................... 39 59 32 53 / 60 0 0 0 ROY............................. 36 58 31 49 / 60 0 0 5 CONCHAS......................... 40 60 38 53 / 40 0 5 5 SANTA ROSA...................... 41 61 37 53 / 30 0 0 10 TUCUMCARI....................... 42 63 35 56 / 30 0 0 5 CLOVIS.......................... 41 65 36 55 / 20 0 0 5 PORTALES........................ 41 65 36 57 / 20 0 5 5 FORT SUMNER..................... 40 65 38 55 / 20 0 0 5 ROSWELL......................... 39 68 36 57 / 10 0 0 10 PICACHO......................... 42 65 38 53 / 10 0 5 10 ELK............................. 41 61 37 52 / 10 0 5 10 && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR THE FOLLOWING ZONES...NMZ513-514. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1010 PM EST FRI DEC 5 2014 .SYNOPSIS...A COLD FRONT WILL APPROACH CENTRAL NORTH CAROLINA FROM THE WEST TONIGHT AND SATURDAY...AND CROSS THE REGION SATURDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE CAROLINAS ON SUNDAY. && .NEAR TERM /TONIGHT/... AS OF 1010 PM FRIDAY... TWO MAIN FORECAST PROBLEMS FOR THIS EVENING...THE FIRST...WILL THERE BE FOG ACROSS THE SOUTHERN COUNTIES...AND SECOND...THE ARRIVAL TIME OF THE PRECIPITATION ON SATURDAY. ADDRESSING THE FOG...MUCH OF CENTRAL NC REMAINS ENSHROUDED IN CLOUD COVER WITH SOME CLEARING ACROSS THE SOUTHWEST. VISIBILITIES FOR THE MOST PART HAVE REMAINED ABOVE TEN MILES AS DEWPOINT DEPRESSIONS HAVE ALSO REMAINED PLUS OR MINUS FIVE DEGREES. AS THE AREA OF CLEARING OVER THE SOUTHWEST MOVES EASTWARD...THERE COULD BE A FEW HOURS BEFORE SUNRISE WHEN THE TEMPERATURE DROPS TO THE DEWPOINT AND SOME PATCHY DENSE FOG WILL BE POSSIBLE. FOR THE MOST PART HOWEVER...LOW STRATUS WILL BE THE MORE LIKELY SCENARIO WITH SEVERAL SITES IN THE SANDHILLS ALREADY SHOWING MVFR CEILINGS. THE MAIN SYSTEM THAT IS EXPECTED TO GENERATE PRECIPITATION OVER THE AREA ON SATURDAY REMAINS OVER THE TENNESSEE VALLEY AND SHORT TERM MODELS ARE PROGGING THE ARRIVAL OF THE PRECIP TO BE A LITTLE BIT LATER THAN PREVIOUSLY ANTICIPATED. HAVE CUT BACK ON POPS SATURDAY MORNING AND BLEND INTO HIGHER POPS STILL EXPECTED FOR SATURDAY AFTERNOON/EVENING. THE LATEST RAP MODEL ACTUALLY SHOWS PRECIP IN OUR CWA BEGINNING FIRST IN THE EAST IN ASSOCIATION WITH A SMALLER WAVE MOVING IN OFF OF THE SW ATLANTIC AFTER 9Z AND THEN PRECIPITATION ASSOCIATED WITH THE WESTERN SYSTEM APPROACHING THE NW PIEDMONT AFTER 12Z SATURDAY. LOWS TONIGHT WILL RANGE FROM THE LOW TO MIDDLE 40S. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 310 PM FRIDAY... SATURDAY... S/W AND ASSOCIATED SURFACE FRONT WILL BE TO OUR WEST AT 18Z...CROSSING OUR REGION SATURDAY EVENING. LOW-MID LEVEL SOUTH- SOUTHWEST FLOW WILL ADVECT ABUNDANT MOISTURE INTO OUR REGION. MEANWHILE SUFFICIENT LIFT WILL BE PROVIDED BY: A.) DIVERGENCE ALOFT DUE TO THE CAROLINAS BEING IN THE FAVORABLE POSITION OF TWO JETS (ONE EXITING NEW ENGLAND WHILE THE OTHER DIVING SEWD ACROSS THE TN VALLEY); B.) 40-60M/12 HOUR MID LEVEL HEIGHT FALLS; C.) AND LATER IN THE DAY, CONVERGENCE ALONG THE SFC-850MB COLD FRONT. THIS FAVORABLE ATMOSPHERE SHOULD CAUSE NUMEROUS SHOWERS TO OVERSPREAD THE PIEDMONT AND THE NORTHERN COASTAL PLAIN DURING THE MORNING HOURS...AND INTO THE SANDHILLS AND THE REMAINDER OF THE COASTAL PLAIN IN THE AFTERNOON. POTENTIAL EXISTS FOR A FEW THUNDERSTORMS TO OCCUR SATURDAY AFTERNOON- EARLY EVENING AS MID LEVEL LAPSE RATES REACH AS HIGH AS 6.5-7 DEG C/KM AND BULK SHEAR ACHIEVES FAVORABLE VALUES 30-35KTS. LOW LEVEL INSTABILITY LACKING AS SBCAPE IS AOB 200 J/KG WHILE MUCAPE NO HIGHER THAN 200-250 J/KG LATE SATURDAY-SATURDAY EVENING. THUS...EXPECT CONVECTION TO BE ELEVATED WITH LITTLE IF ANY CHANCE OF STORMS BECOMING STRONG/SEVERE. HIGH TEMPS SATURDAY STILL A CHALLENGE...DEPENDENT UPON EXTENT OF RAIN SHOWERS. STILL FAVOR MAX TEMPS SLIGHTLY COOLER THAN GUIDANCE ACROSS THE PIEDMONT AS A SHORT-LIVED IN-SITU OR HYBRID CAD MAY SET UP EARLY SATURDAY. CONVERSELY...IF SHOWERS HOLD OFF LONG ENOUGH...TEMPS IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN MAY WARM INTO THE MID-UPPER 60S. SATURDAY NIGHT... SURFACE COLD FRONT PROGRESSES EAST ACROSS CENTRAL NC IN THE EVENING...EXITING OUR COASTAL PLAIN COUNTIES AROUND OR SHORTLY AFTER MIDNIGHT. THE 850-700MB TROUGHS FOLLOW SHORTLY AFTERWARDS. LOW-MID LEVEL N-NW FLOW IN THE WAKE OF THE TROUGH PASSAGE WILL AID TO DIMINISH SHOWER COVERAGE IN THE WEST SATURDAY EVENING...AND OVERNIGHT IN THE EAST. PARTIAL CLEARING SHOULD INITIATE IN THE NORTH-NW AFTER MIDNIGHT. SURFACE FRONTAL PASSAGE WILL BE NOTED BY WINDS VEERING TO THE N-NW AND INITIALLY GUSTING AROUND 20KTS. MIN TEMPS LOW-MID 40S NORTH TO UPPER 40S SE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 220 PM FRIDAY... SUNDAY AND SUNDAY NIGHT: THE LATEST RUN OF THE ECMWF AGREES WELL WITH THE GFS IN REGARD TO THE LOW AND ITS ASSOCIATED COLD FRONT MOVING OFF THE CAROLINA COAST PRIOR TO 12Z SUNDAY. AS SUCH...HAVE A DRY FORECAST FOR SUNDAY AND SUNDAY NIGHT. THE BIG QUESTION WILL BE HOW QUICKLY THE SKIES CLEAR AND HOW THAT WILL AFFECT TEMPERATURES. FOR NOW...EXPECT HIGHS IN THE UPPER 40S NW TO 723MID 50S SOUTH AND EAST...ALTHOUGH IF SKIES CLEAR QUICKER/SLOWER THAT COULD CHANGE BY A COUPLE/FEW DEGREES. LOWS GENERALLY IN LOW 30S NW TO UPPER 30S SE. MONDAY THROUGH FRIDAY: CONFIDENCE IS STILL NOT TERRIBLY HIGH FOR NEXT WEEK...HOWEVER IT HAS INCREASED SOME OVERALL AS THE MODELS APPEAR TO BE SLOWLY COMING INTO BETTER AGREEMENT. THE ECMWF SEEMS TO BE TRENDING MORE TOWARD THE GFS WITH THE UPPER LEVEL LOW THAT MOVES THROUGH THE GREAT LAKES AND NORTHEAST U.S. TOWARD THE END OF NEXT WEEK. ALTHOUGH IT CONTINUES TO BE DEEPER WITH THE UPPER LEVEL TROUGH AND STILL TRIES TO GENERATE A BIT OF PRECIPITATION OVER PORTIONS OF THE CAROLINAS EARLY IN THE WEEK. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO THAT LOW...AND GIVEN THE MODEL TREND...EXPECT IT TO STAY MAINLY WELL NORTH OF THE REGION AND BE OF LITTLE CONSEQUENCE IN THE PRECIPITATION DEPARTMENT FOR CENTRAL NC AT THIS TIME. WITH THAT HYPOTHESIS IN MIND...EXPECT NEXT WEEK TO BE GENERALLY DRY...WITH HIGH PRESSURE DOMINATING AT THE SURFACE. THE FIRST HIGH WILL RIDGE IN FROM THE NORTHEAST AND RESULT IN A WEDGE OF A COLD AIR OVER THE AREA. A REINFORCING SHOT OF COLD AIR WILL PUSH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH ANOTHER AREA OF HIGH PRESSURE SUBSEQUENTLY BUILDING IN THROUGH THE END OF THE WEEK. HIGHS ON MONDAY WILL BE THE COOLEST OF THE PERIOD...MID 40S NW TO LOW 50S SE. HIGHS WILL CONTINUE TO BE A LITTLE BIT OF A RO723LLER COASTER THROUGH THE REST OF THE WEEK...WITH LOW TO MID 50S EXPECTED ON TUESDAY AND FRIDAY...BUT UPPER 40S TO LOW 50S WEDNESDAY AND THURSDAY. LOWS WILL GENERALLY DECREASE FROM THE LOW 30S NW TO UPPER 30S SE MONDAY NIGHT TO UPPER 20S ACROSS THE AREA BY WED AND THU NIGHTS...MODERATING AGAIN INTO THE LOW 30S FRI NIGHT. && .AVIATION /00Z FRIDAY THROUGH WEDNESDAY/... AS OF 720 PM FRIDAY... 24 HOUR TAF PERIOD: VFR CONDITIONS WILL CONTINUE THIS EVENING AT KRDU/KFAY/KRWI... WHILE MVFR CIGS WILL CONTINUE TO SLOWLY LIFT TO VFR AT KGSO/KINT THIS EVENING. EXPECT VFR CONDITIONS AT ALL CENTRAL NC TAF SITES BY AROUND 03Z OR SO. HOWEVER... VFR CONDITIONS WILL BE SHORT LIVED. A COLD FRONT WILL APPROACH THE REGION FROM THE WEST TONIGHT AND CROSS CENTRAL NC SATURDAY AFTERNOON INTO THE EVENING. MVFR TO IFR CIGS WILL DEVELOP IN ADVANCE OF THE FRONT ON SATURDAY MORNING...WITH EVEN SOME LIFR CONDITIONS POSSIBLE AS A BAND OF SHOWERS AND POSSIBLY EVEN SOME EMBEDDED THUNDERSTORMS CROSS THE AREA SATURDAY MORNING INTO SATURDAY EVENING. THE SHOWERS WILL DIMINISH IN COVERAGE FROM THE SW...BEGINNING SATURDAY EVENING IN THE SOUTHERN PIEDMONT...REACHING THE NORTHERN COASTAL PLAIN AFTER 06Z SUNDAY. MVFR/IFR CEILINGS WILL PERSIST THROUGH SATURDAY EVENING THOUGH... WITH CEILINGS LIFTING LATE SATURDAY NIGHT INTO SUNDAY MORNING. WHILE VFR CONDITIONS ARE EXPECTED SUNDAY AS HIGH PRESSURE BUILDS INTO THE REGION FROM NEW ENGLAND...BRISK N-NE WINDS WILL GUSTS CLOSE TO 25KTS. MVFR CEILINGS WILL BE POSSIBLE MONDAY INTO TUESDAY WITH IMPROVING CONDITIONS ANTICIPATED BY WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...KC AVIATION...BSD/WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1007 PM EST FRI DEC 5 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A COASTAL TROUGH WILL LIFT NORTH AS A WARM FRONT ON SATURDAY...AHEAD OF A COLD FRONT WHICH WILL MOVE ACROSS THE AREA SATURDAY NIGHT. THIS COLD FRONT WILL BRING A PERIOD OF SHOWERS WITH AN ISOLATED THUNDERSTORM POSSIBLE. A STRONG WEDGE OF HIGH PRESSURE WILL BUILD SOUTH SUNDAY AND MONDAY...BRINGING GUSTY NORTH WINDS AND MUCH COOLER TEMPERATURES. CANADIAN HIGH PRESSURE NEXT WEEK WILL MAINTAIN SEASONABLY COOL TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM FRIDAY...A COASTAL TROUGH DEVELOPING ACROSS THE WATERS IS EXPECTED TO DRIFT TO THE COAST OVERNIGHT. CONVERGENT FLOW IN ASSOCIATION WITH THE TROUGH SHOULD HELP TO BRING SOME OF THE OFFSHORE SHOWERS ONTO THE COAST LATE TONIGHT. THE HIGH RESOLUTION HRRR IS MOST BULLISH WITH THIS SCENARIO...PRIMARILY FOR THE CAPE FEAR AREA LATE TONIGHT. OTHERWISE AS CHILLY HIGH PRESSURE DRIFTS OFFSHORE AND A TROUGH APPROACHES FROM THE W...A DEEP S TO SW FLOW WILL ENVELOP THE EASTERN CAROLINAS. THE COLUMN WILL CONTINUE TO SLOWLY MOISTEN...PRECIPITABLE WATER VALUES WILL REACH NEAR 1.25 INCHES BY SUNRISE. SHOWERS ASSOCIATED WITH THE AFOREMENTIONED TROUGH WILL REMAIN W OF THE FORECAST AREA INTO EARLY SAT MORNING. A WARM AIR ADVECTION PATTERN AND INCREASING MOISTURE CONTENT WILL BRING A GOOD DEAL OF CLOUDINESS THROUGH THE NIGHT. THE CLOUDS SHOULD HELP TO FLATTEN THE TEMP CURVE WITH LOWS MAINLY IN THE MID AND UPPER 40S INLAND AND LOWER 50S AT THE COAST...SO LITTLE TEMP MOVEMENT THROUGH THE NIGHT. ALTHOUGH MODELS ARE INDICATING A PRONOUNCED NEAR SURFACE INVERSION DEVELOPING...THEY ARE RELUCTANT TO SATURATE THE LEVEL CLOSEST TO THE GROUND. ALSO... USING A UPS FOG METHODOLOGY GRIDDED SMART TOOL...FOG IS EXPECTED TO DEVELOP W OF THE FORECAST AREA AND ADVECT NORTHWARD WITH TIME. THUS...STILL LOOKS AS THOUGH SIGNIFICANT FOG WILL HAVE A DIFFICULT TIME DEVELOPING AND WILL FAVOR LOW STRATUS OVER FOG AT THIS TIME...BUT CONTINUE TO MONITOR NEAR TERM TRENDS. THIS LOW STRATUS MAY PRODUCE SOME SPOTTY DRIZZLE FROM TIME TO TIME AND HAVE ADDED PATCHY DRIZZLE TO THE FORECAST TOWARD MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COASTAL TROUGH LIFTING NORTH AS A WARM FRONT SATURDAY MORNING WILL CREATE A WARM DAY...ESPECIALLY ALONG THE COAST...BUT RAIN CHANCES WILL INCREASE RAPIDLY LATE IN THE DAY. AS THE COASTAL TROUGH LIFTS NORTH EARLY...WAA WILL FOLLOW THROUGH THE AFTN...WITH 850MB TEMPS CLIMBING TO AROUND 10C BY SATURDAY AFTN. AS THIS OCCURS HOWEVER...CLOUD COVER WILL BE ON THE INCREASE THANKS TO MOIST ADVECTION AND PVA AHEAD OF A SHORTWAVE WHICH WILL MOVE JUST NORTH OF THE AREA SATURDAY NIGHT. BENEATH THIS SHORTWAVE...A SURFACE LOW WILL PUSH EAST NEAR THE NC/VA BORDER...DRAGGING A COLD FRONT ACROSS THE CWA SATURDAY NIGHT. AS PWATS RISE TO ABOUT 1.25 INCHES AND MID-LEVEL LAPSE RATES CLIMB TOWARDS 7C/KM...SCATTERED SHOWERS WITH ISOLATED TSTMS ARE EXPECTED. INSTABILITY REMAINS MINIMAL...BUT CANNOT RULE OUT A FEW LIGHTNING STRIKES...AND THIS IS ECHOED BY THE GENERAL RISK ENCOMPASSING THE ILM CWA IN THE SWODY2. TOTAL QPF WILL NOT BE VERY HIGH...BUT BRIEF PERIODS OF HEAVY RAIN IS POSSIBLE WITHIN A FEW HOURS EITHER SIDE OF SATURDAY EVENING. COOL ADVECTION BEGINS IN EARNEST BEHIND THE COLD FRONT LATE SATURDAY NIGHT...SO TEMPS WHICH WILL RISE TOWARDS 70 ALONG THE COAST SATURDAY AFTN...MID 60S WELL INLAND...WILL DROP RAPIDLY INTO THE LOW 40S WELL NW...TO AROUND 50 AT THE COAST...BY SUNDAY MORNING. A QUIETER BUT MUCH COOLER DAY ON SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE DEVELOPS BEHIND THE COLD FRONT FROM SATURDAY NIGHT. WITH LOW-LEVEL MOISTURE PROGGED TO REMAIN HIGH BENEATH THE WEDGE...PARTLY TO MOSTLY CLOUDY CONDITIONS WILL PERSIST MUCH OF SUNDAY. THIS COMBINED WITH COOL ADVECTION WILL LIMIT WARMING...AND HIGHS MAY BE REACHED VERY EARLY IN THE DAY...WITH LITTLE DIURNAL RANGE. EXPECT HIGHS ONLY IN THE LOW 50S IN THE FAR NORTH...TO MID 50S IN THE SOUTH. SOME CLEARING WILL OCCUR VERY LATE...AND CONTINUED CAA WILL HELP MINS FALL INTO THE UPPER 30S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...THE MID LEVEL PATTERN WILL BE QUITE PROGRESSIVE THROUGH THE PERIOD WITH THE AREA REMAINING VOID OF ANY SIGNIFICANT PRECIPITATION. INITIALLY A LINGERING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST MAY PROVIDE A FEW SHOWERS...MORESO ALONG THE COAST MONDAY BEFORE A COLD FRONT...ASSOCIATED WITH FAIRLY STRONG SHORTWAVE MOVING THROUGH THE MIDWEST SWEEPS THE AREA CLEAN. BEYOND THIS A WEAKENING CYCLONIC FLOW ALOFT WILL PREVAIL ACROSS THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE UPPER MIDWEST TO ESSENTIALLY OVER THE AREA BY FRIDAY THUS A DRY FORECAST. TEMPERATURES TRENDS LOOK A LITTLE BELOW CLIMATOLOGY WITH HIGHS MOSTLY IN THE 50S AND LOWS IN THE LOWER TO MIDDLE 30S && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RATHER LOW CONFIDENCE ON THE BACK END OF THE FORECAST PERIOD WITH RESPECT TO CEILINGS AND THE TIMING OF PRECIP. LOOKS LIKE THERE COULD BE TWO BATCHES OF RAIN/SHOWERS: THE FIRST AROUND SUNRISE WITH A COASTAL TROUGH...THEN ANOTHER ROUND IN THE LATE AFTERNOON AHEAD OF A COLD FRONT. MODELS ARE IN REASONABLE AGREEMENT INTRODUCING IFR STRATUS/FOG AROUND DAYBREAK IF NOT BEFORE...AND THIS MAKES SENSE GIVEN THE WEAK WARM AIR ADVECTION. THE HRRR MODEL THINKS THAT ILM STANDS THE BEST CHANCE FOR MORNING PRECIP...BUT THE MYRTLES COULD ALSO GET INTO THE ACT. THINK THE MORNING PRECIP WILL GIVE WAY TO MVFR CEILINGS AND SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT WHICH WILL ARRIVE AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PERIODS OF MVFR/IFR CIGS ARE LIKELY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GUSTY NORTH WINDS SUN/MON BEHIND THE COLD FRONT. BECOMING VFR DURING TUE. VFR WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM FRIDAY...A COASTAL TROUGH WILL BE IN CLOSE PROXIMITY THROUGH TONIGHT AND LIKELY JUST ABOUT ON THE IMMEDIATE COAST AROUND DAYBREAK SAT. NE WINDS ARE EXPECTED TO SHIFT TO THE E OR ESE OVERNIGHT WITH ITS PASSAGE. WIND SPEEDS WILL BE UP TO 10 TO 15 KT LATE THIS EVE...DECREASING TO 10 KT OR LESS OVERNIGHT. SEAS WILL BE 3 TO 4 FT WITH A 8 TO 10 SECOND EASTERLY SWELL PRESENT. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...QUIET MARINE CONDITIONS TO START THE PERIOD...BUT RAPID DETERIORATION IS EXPECTED ON SUNDAY. WEAK COASTAL TROUGH WILL LIFT NORTH ON SATURDAY...WITH WINDS TURNING FROM SE TO SW THROUGH THE AFTN...BUT AT LIGHT SPEEDS. LOW PRESSURE MOVING NORTH OF THE AREA WILL DRAG A COLD FRONT ACROSS THE WATERS SATURDAY NIGHT...AND WINDS WILL TURN ABRUPTLY TO THE NORTH AT 15-20 KTS BY SUNDAY MORNING. SEAS ON SATURDAY WILL BE GENERALLY 2-4 FT REGARDLESS OF WIND DIRECTION...BUT WILL BEGIN TO RISE LATE BEHIND THE COLD FRONT. GALE WATCH HAS BEEN HOISTED FOR THE NC WATERS BEGINNING SUNDAY MORNING...AND THERE IS PRETTY HIGH CONFIDENCE IN A GALE OCCURRING SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST. THIS WILL CAUSE A TIGHT GRADIENT OVER THE WATERS...AND WIND WILL BECOME NE AT 20-30 KTS ON SUNDAY...WITH FREQUENT GUSTS TO 35 KTS OR MORE EXPECTED ACROSS THE NC WATERS. THERE IS LOWER CONFIDENCE IN GALE-FORCE WINDS ACROSS SC WATERS...BUT AT LEAST A STRONG SMALL CRAFT ADVISORY IS EXPECTED. THESE STRONG WINDS WILL ALSO PUSH SEAS UP TO TO 5-9 FT ON SUNDAY...WITH THE EXCEPTION BEING THE WAVE SHADOWED REGION SW OF BRUNSWICK COUNTY. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...NEXT WEEK WILL NOT BE THE BEST OF TIMES FOR THE MARINE COMMUNITY AS BLUSTERY CONDITIONS AND ELEVATED SEAS WILL CONTINUE. FOR MONDAY A POTENT NORTHERLY FLOW WILL CONTINUE AS LOW PRESSURE MOVES WELL OFF TO THE NORTHEAST AND MASSIVE HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. EXPECT WINDS OF 20-25 KNOTS...POSSIBLY HIGHER WITH CERTAIN SMALL CRAFT CONDITIONS AND POSSIBLY GALES. THE WINDS DO DIMINISH THROUGHOUT THE DAY TO SETTLE AT 10-15 KNOTS BY TUESDAY MORNING. HERE THE WINDS WILL REMAIN THROUGH WEDNESDAY. SEAS WILL BE HIGHEST MONDAY WITH 3-6 FEET DROPPING TO 2-5 FEET TUESDAY AND WEDNESDAY. && .TIDES/COASTAL FLOODING... AS OF 700 PM WEDNESDAY...THE FULL MOON IS ON SATURDAY. WE EXPECT ELEVATED WATER LEVELS DURING THE TIME OF HIGH TIDE THROUGH THE WEEKEND. THE MORNING HIGH TIDE WILL BE HIGHEST AND THIS IS WHEN WE EXPECT THE TIDE TO COME UP WELL ONTO THE BEACH. STRONG NNE WINDS SUNDAY AND SUNDAY NIGHT WILL HELP TO ENHANCE THE ASTRONOMICAL EFFECTS. THE LOWER CAPE FEAR RIVER WILL ALSO EXPERIENCE HIGHER THAN PREDICTED WATER LEVELS AND MAY REACH COASTAL FLOOD ADVISORY CRITERIA DURING THE MORNING HIGH TIDE THROUGH THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR AMZ250-252. && $$ NEAR TERM...RJD SHORT TERM...JDW LONG TERM...SHK AVIATION...DL TIDES/COASTAL FLOODING...RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
749 PM EST FRI DEC 5 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A COASTAL TROUGH WILL LIFT NORTH AS A WARM FRONT ON SATURDAY...AHEAD OF A COLD FRONT WHICH WILL MOVE ACROSS THE AREA SATURDAY NIGHT. THIS COLD FRONT WILL BRING A PERIOD OF SHOWERS WITH AN ISOLATED THUNDERSTORM POSSIBLE. A STRONG WEDGE OF HIGH PRESSURE WILL BUILD SOUTH SUNDAY AND MONDAY...BRINGING GUSTY NORTH WINDS AND MUCH COOLER TEMPERATURES. CANADIAN HIGH PRESSURE NEXT WEEK WILL MAINTAIN SEASONABLY COOL TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 700 PM FRIDAY...A COASTAL TROUGH DEVELOPING ACROSS THE WATERS IS EXPECTED TO DRIFT TO THE COAST OVERNIGHT. CONVERGENT FLOW IN ASSOCIATION WITH THE TROUGH SHOULD HELP TO BRING SOME OF THE OFFSHORE SHOWERS ONTO THE COAST LATE TONIGHT. THE HIGH RESOLUTION HRRR IS MOST BULLISH WITH THIS SCENARIO...PRIMARILY FOR THE CAPE FEAR AREA LATE TONIGHT. OTHERWISE AS CHILLY HIGH PRESSURE DRIFTS OFFSHORE AND A TROUGH APPROACHES FROM THE W...A DEEP S TO SW FLOW WILL ENVELOP THE EASTERN CAROLINAS. THE COLUMN WILL CONTINUE TO SLOWLY MOISTEN...PRECIPITABLE WATER VALUES WILL REACH NEAR 1.25 INCHES BY SUNRISE. SHOWERS ASSOCIATED WITH THE AFOREMENTIONED TROUGH WILL REMAIN W OF THE FORECAST AREA INTO EARLY SAT MORNING. A WARM AIR ADVECTION PATTERN AND INCREASING MOISTURE CONTENT WILL BRING A GOOD DEAL OF CLOUDINESS THROUGH THE NIGHT. THE CLOUDS SHOULD HELP TO FLATTEN THE TEMP CURVE WITH LOWS MAINLY IN THE MID AND UPPER 40S INLAND AND LOWER 50S AT THE COAST. ALTHOUGH MODELS ARE INDICATING A PRONOUNCED NEAR SURFACE INVERSION DEVELOPING...THEY ARE RELUCTANT TO SATURATE THE LEVEL CLOSEST TO THE GROUND. THUS...SIGNIFICANT FOG MAY HAVE A DIFFICULT TIME DEVELOPING AND WILL FAVOR LOW STRATUS OVER FOG AT THIS TIME...BUT CONTINUE TO MONITOR NEAR TERM TRENDS. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COASTAL TROUGH LIFTING NORTH AS A WARM FRONT SATURDAY MORNING WILL CREATE A WARM DAY...ESPECIALLY ALONG THE COAST...BUT RAIN CHANCES WILL INCREASE RAPIDLY LATE IN THE DAY. AS THE COASTAL TROUGH LIFTS NORTH EARLY...WAA WILL FOLLOW THROUGH THE AFTN...WITH 850MB TEMPS CLIMBING TO AROUND 10C BY SATURDAY AFTN. AS THIS OCCURS HOWEVER...CLOUD COVER WILL BE ON THE INCREASE THANKS TO MOIST ADVECTION AND PVA AHEAD OF A SHORTWAVE WHICH WILL MOVE JUST NORTH OF THE AREA SATURDAY NIGHT. BENEATH THIS SHORTWAVE...A SURFACE LOW WILL PUSH EAST NEAR THE NC/VA BORDER...DRAGGING A COLD FRONT ACROSS THE CWA SATURDAY NIGHT. AS PWATS RISE TO ABOUT 1.25 INCHES AND MID-LEVEL LAPSE RATES CLIMB TOWARDS 7C/KM...SCATTERED SHOWERS WITH ISOLATED TSTMS ARE EXPECTED. INSTABILITY REMAINS MINIMAL...BUT CANNOT RULE OUT A FEW LIGHTNING STRIKES...AND THIS IS ECHOED BY THE GENERAL RISK ENCOMPASSING THE ILM CWA IN THE SWODY2. TOTAL QPF WILL NOT BE VERY HIGH...BUT BRIEF PERIODS OF HEAVY RAIN IS POSSIBLE WITHIN A FEW HOURS EITHER SIDE OF SATURDAY EVENING. COOL ADVECTION BEGINS IN EARNEST BEHIND THE COLD FRONT LATE SATURDAY NIGHT...SO TEMPS WHICH WILL RISE TOWARDS 70 ALONG THE COAST SATURDAY AFTN...MID 60S WELL INLAND...WILL DROP RAPIDLY INTO THE LOW 40S WELL NW...TO AROUND 50 AT THE COAST...BY SUNDAY MORNING. A QUIETER BUT MUCH COOLER DAY ON SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE DEVELOPS BEHIND THE COLD FRONT FROM SATURDAY NIGHT. WITH LOW-LEVEL MOISTURE PROGGED TO REMAIN HIGH BENEATH THE WEDGE...PARTLY TO MOSTLY CLOUDY CONDITIONS WILL PERSIST MUCH OF SUNDAY. THIS COMBINED WITH COOL ADVECTION WILL LIMIT WARMING...AND HIGHS MAY BE REACHED VERY EARLY IN THE DAY...WITH LITTLE DIURNAL RANGE. EXPECT HIGHS ONLY IN THE LOW 50S IN THE FAR NORTH...TO MID 50S IN THE SOUTH. SOME CLEARING WILL OCCUR VERY LATE...AND CONTINUED CAA WILL HELP MINS FALL INTO THE UPPER 30S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...THE MID LEVEL PATTERN WILL BE QUITE PROGRESSIVE THROUGH THE PERIOD WITH THE AREA REMAINING VOID OF ANY SIGNIFICANT PRECIPITATION. INITIALLY A LINGERING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST MAY PROVIDE A FEW SHOWERS...MORESO ALONG THE COAST MONDAY BEFORE A COLD FRONT...ASSOCIATED WITH FAIRLY STRONG SHORTWAVE MOVING THROUGH THE MIDWEST SWEEPS THE AREA CLEAN. BEYOND THIS A WEAKENING CYCLONIC FLOW ALOFT WILL PREVAIL ACROSS THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE UPPER MIDWEST TO ESSENTIALLY OVER THE AREA BY FRIDAY THUS A DRY FORECAST. TEMPERATURES TRENDS LOOK A LITTLE BELOW CLIMATOLOGY WITH HIGHS MOSTLY IN THE 50S AND LOWS IN THE LOWER TO MIDDLE 30S && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RATHER LOW CONFIDENCE ON THE BACK END OF THE FORECAST PERIOD WITH RESPECT TO CEILINGS AND THE TIMING OF PRECIP. LOOKS LIKE THERE COULD BE TWO BATCHES OF RAIN/SHOWERS: THE FIRST AROUND SUNRISE WITH A COASTAL TROUGH...THEN ANOTHER ROUND IN THE LATE AFTERNOON AHEAD OF A COLD FRONT. MODELS ARE IN REASONABLE AGREEMENT INTRODUCING IFR STRATUS/FOG AROUND DAYBREAK IF NOT BEFORE...AND THIS MAKES SENSE GIVEN THE WEAK WARM AIR ADVECTION. THE HRRR MODEL THINKS THAT ILM STANDS THE BEST CHANCE FOR MORNING PRECIP...BUT THE MYRTLES COULD ALSO GET INTO THE ACT. THINK THE MORNING PRECIP WILL GIVE WAY TO MVFR CEILINGS AND SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT WHICH WILL ARRIVE AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PERIODS OF MVFR/IFR CIGS ARE LIKELY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GUSTY NORTH WINDS SUN/MON BEHIND THE COLD FRONT. BECOMING VFR DURING TUE. VFR WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 700 PM FRIDAY...A COASTAL TROUGH WILL BE IN CLOSE PROXIMITY THROUGH TONIGHT AND LIKELY JUST ABOUT ON THE IMMEDIATE COAST AROUND DAYBREAK SAT. NE WINDS ARE EXPECTED TO SHIFT TO THE E AND SE OVERNIGHT WITH ITS PASSAGE. WIND SPEEDS WILL BE UP TO 10 TO 15 KT THIS EVE...DECREASING TO 10 KT OR LESS OVERNIGHT. SEAS WILL BE 3 TO 5 FT WITH A 8 TO 10 SECOND EASTERLY SWELL PRESENT. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...QUIET MARINE CONDITIONS TO START THE PERIOD...BUT RAPID DETERIORATION IS EXPECTED ON SUNDAY. WEAK COASTAL TROUGH WILL LIFT NORTH ON SATURDAY...WITH WINDS TURNING FROM SE TO SW THROUGH THE AFTN...BUT AT LIGHT SPEEDS. LOW PRESSURE MOVING NORTH OF THE AREA WILL DRAG A COLD FRONT ACROSS THE WATERS SATURDAY NIGHT...AND WINDS WILL TURN ABRUPTLY TO THE NORTH AT 15-20 KTS BY SUNDAY MORNING. SEAS ON SATURDAY WILL BE GENERALLY 2-4 FT REGARDLESS OF WIND DIRECTION...BUT WILL BEGIN TO RISE LATE BEHIND THE COLD FRONT. GALE WATCH HAS BEEN HOISTED FOR THE NC WATERS BEGINNING SUNDAY MORNING...AND THERE IS PRETTY HIGH CONFIDENCE IN A GALE OCCURRING SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST. THIS WILL CAUSE A TIGHT GRADIENT OVER THE WATERS...AND WIND WILL BECOME NE AT 20-30 KTS ON SUNDAY...WITH FREQUENT GUSTS TO 35 KTS OR MORE EXPECTED ACROSS THE NC WATERS. THERE IS LOWER CONFIDENCE IN GALE-FORCE WINDS ACROSS SC WATERS...BUT AT LEAST A STRONG SMALL CRAFT ADVISORY IS EXPECTED. THESE STRONG WINDS WILL ALSO PUSH SEAS UP TO TO 5-9 FT ON SUNDAY...WITH THE EXCEPTION BEING THE WAVE SHADOWED REGION SW OF BRUNSWICK COUNTY. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...NEXT WEEK WILL NOT BE THE BEST OF TIMES FOR THE MARINE COMMUNITY AS BLUSTERY CONDITIONS AND ELEVATED SEAS WILL CONTINUE. FOR MONDAY A POTENT NORTHERLY FLOW WILL CONTINUE AS LOW PRESSURE MOVES WELL OFF TO THE NORTHEAST AND MASSIVE HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. EXPECT WINDS OF 20-25 KNOTS...POSSIBLY HIGHER WITH CERTAIN SMALL CRAFT CONDITIONS AND POSSIBLY GALES. THE WINDS DO DIMINISH THROUGHOUT THE DAY TO SETTLE AT 10-15 KNOTS BY TUESDAY MORNING. HERE THE WINDS WILL REMAIN THROUGH WEDNESDAY. SEAS WILL BE HIGHEST MONDAY WITH 3-6 FEET DROPPING TO 2-5 FEET TUESDAY AND WEDNESDAY. && .TIDES/COASTAL FLOODING... AS OF 700 PM WEDNESDAY...THE FULL MOON IS ON SATURDAY. WE EXPECT ELEVATED WATER LEVELS DURING THE TIME OF HIGH TIDE THROUGH THE WEEKEND. THE MORNING HIGH TIDE WILL BE HIGHEST AND THIS IS WHEN WE EXPECT THE TIDE TO COME UP WELL ONTO THE BEACH. STRONG NNE WINDS SUNDAY AND SUNDAY NIGHT WILL HELP TO ENHANCE THE ASTRONOMICAL EFFECTS. THE LOWER CAPE FEAR RIVER WILL ALSO EXPERIENCE HIGHER THAN PREDICTED WATER LEVELS AND MAY REACH COASTAL FLOOD ADVISORY CRITERIA DURING THE MORNING HIGH TIDE THROUGH THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR AMZ250-252. && $$ NEAR TERM...RJD SHORT TERM...JDW LONG TERM...SHK AVIATION...DL TIDES/COASTAL FLOODING...RJD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
149 AM EST THU DEC 4 2014 .SYNOPSIS...A COLD FRONT WILL DRIFT SOUTH THROUGH OUR AREA THIS MORNING. COOL SURFACE HIGH PRESSURE WILL THEN RIDGE SOUTH ACROSS THE MIDDLE ATLANTIC AND CAROLINAS THROUGH FRIDAY NIGHT...BENEATH A COUPLE OF PASSING UPPER LEVEL DISTURBANCES. THE FRONT WILL WEAKEN AND RETREAT NORTH AS A WARM FRONT SATURDAY...JUST AHEAD OF ANOTHER COLD FRONT THAT WILL MOVE THROUGH THE AREA SATURDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1035 PM WEDNESDAY... COLD FRONT JUST ABOUT TO ENTER THE WESTERN PART OF THE CWA... AND SHOULD CROSS THE AREA OVERNIGHT. LACK OF UPPER LEVEL SUPPORT... DRY AIR THROUGH MUCH OF THE MID AND LOW LEVELS... EXCEPT FOR THE NEAR SURFACE LAYER AS SHOWN ON THE KGSO AND KMHX SOUNDINGS... WILL PRECLUDE ANY PRECIPITATION IN ASSOCIATION WITH ITS PASSAGE. PATCHY FOG... SOME LOCALLY DENSE... HAS FORMED AHEAD OF THE FRONT... BUT WILL BE SCOURED OUT ALONG WITH THE LOW CLOUDS OVER THE NEXT FEW HOURS AS MIXING INCREASES. UPPER LEVEL MOISTURE AND HIGH CLOUDS WILL REMAIN ACROSS THE AREA. LOWS IN THE UPPER 30S TO MID 40S NORTH TO SOUTH. THURSDAY AND THURSDAY NIGHT...A SERIES OF MID-LEVEL SHORTWAVES ARE FORECAST BY THE NAM AND THE GFS TO MOVE THROUGH CENTRAL NORTH CAROLINA IN THIS PERIOD. THE STRONGEST ON BOTH OF THOSE SETS OF GUIDANCE IS THURSDAY...COINCIDENT WITH A MID-LEVEL WAVE MOVING EAST OUT OF THE SOUTHERN PLAINS ON WATER VAPOR IMAGERY. DURING THIS TIME...OVER MOST OF CENTRAL NORTH CAROLINA THERE SHOULD BE 850MB THETA-E TROUGHINESS...SO OVERALL MOISTURE SHOULD BE LIMITED EXCEPT IN THE UPPER-LEVELS...AND POSSIBLY IN THE BOUNDARY LAYER OVER THE FAR SOUTH ALTHOUGH LIFT IS FORECAST TO BE MEAGER WITH BASICALLY 850MB DIVERGENCE AND LITTLE UPPER DIFFLUENCE. BY THURSDAY NIGHT... OVERALL MOISTURE STARTS TO INCREASE ON THE WEST SIDE OF THE SURFACE HIGH...WITH MORE OF THE MOISTURE INCREASE OVER THE MOUNTAINS INTO VIRGINIA. BOTH THE GFS AND THE NAM SHOW SLIGHT ISENTROPIC LIFT ON THE 300K SURFACE OVER THE NORTHWEST PIEDMONT THURSDAY NIGHT...WITH THE GFS AND NAM BUFR SOUNDINGS NOTING MOISTENING OF THE 850MB LAYER BUT WITH THE NAM SHOWING MORE MOISTENING OF THE MID-LAYERS. MOS GUIDANCE POPS ARE CREEPING UP INTO THE 30S ESPECIALLY FROM RALEIGH NORTH AND WEST...BUT GUIDANCE QPF STAYS JUST BELOW ZERO IN CENTRAL NORTH CAROLINA AND HRRR WRF GUIDANCE KEEPS THE APPEARANCE OF ANY MEASURABLE RAIN JUST TO OUR NORTH AND WEST. AVERAGING THE DRIER GFS AND THE MORE MOIST NAM WITH THE HRRR AND MOS GUIDANCE SUGGESTS A SLIGHT CHANCE OF RAIN OR SPRINKLES THURSDAY NIGHT MAINLY NORTH OF A LINE FROM ABOUT KEXX TO KTDF. 1000-850MB THICKNESSES WOULD SUPPORT HIGHS AT LEAST A CATEGORY ABOVE GUIDANCE FOR THURSDAY...BUT BEHIND THE FRONT AND WITH AT LEAST SOME PERIODS OF HIGH CLOUDS...WILL LEAN TOWARD THE MOS GUIDANCE VALUES WHICH ARE VERY CLOSE BETWEEN THE MET AND THE MAV...FOR HIGHS IN THE LOWER TO MID 50S OVERALL. COULD SEE THE WARMER MAV MINIMUM TEMPERATURES VERIFY THURSDAY NIGHT IF THERE ARE ENOUGH HIGH CLOUDS THROUGHOUT CENTRAL NORTH CAROLINA...BUT WITH A RELATIVE MINIMUM FOR A TIME THURSDAY EVENING ESPECIALLY EAST LEANED TOWARD THE WARMER MAV WEST AND TOWARD A BLEND OR THE COOLER VALUES EAST...37 TO 42. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 310 PM WEDNESDAY... FRIDAY...DRY AIR SURFACE RIDGE WILL EXTEND ACROSS THE FORECAST AREA EMANATING FROM A PARENT HIGH (1040+MB) OVER NORTHERN NEW ENGLAND. ALOFT A S/W WILL BE LIFTING NEWD FROM THE SOUTHERN PLAINS INTO THE LOWER OH VALLEY. WESTERLY FLOW IN THE MID-UPPER LEVELS WILL ADVECT MOISTURE FROM THIS SYSTEM INTO CENTRAL NC. THER COMBINATION OF A COOL STABLE AIR MASS NEAR THE SURFACE AND THE INCREASINGLY MOIST AIR MASS ALOFT SHOULD RESULT IN A VARIABLY CLOUDY AND SEASONABLY COOL DAY OVER OUR REGION. THICKER CLOUDS ANTICIPATED ACROSS THE NW SHOULD HOLD TEMPS BELOW 50 DEGREES. SOME POTENTIAL FOR PARTIAL/FILTERED SUN IN THE SE WHICH WILL ALLOW TEMPS TO WARM SOLIDLY INTO THE 50S. FRIDAY NIGHT...THE LOWER OH VALLEY SYSTEM WILL ADVANCE FARTHER EAST. INCREASING SOUTHERLY FLOW ABOVE THE SURFACE-BASED COOL DOME SHOULD INITIATE SOME OVERRUNNING OVER THE PIEDMONT LATE FRIDAY NIGHT/EARLY SATURDAY. CURRENTLY EXPECT ANY PRECIP TO BE SPOTTY AND LIGHT...MAINLY CONFINED TO AREAS WEST-NW OF HIGHWAY 1. MAY SEE AREAS OF FOG AS WELL. MIN TEMPS MID-UPPER 40S. SATURDAY AND SATURDAY NIGHT...S/W AND ATTENDANT SFC FRONT WILL CONTINUE TO LIFT E-NE. THIS WILL BRING AN INCREASING THREAT FOR RAIN ACROSS CENTRAL NC...ESPECIALLY LATE MORNING THROUGH EARLY EVENING. RESIDUAL CAD AIR MASS MAY HOLD ON LONGER IN THE FAVORED NW PIEDMONT THAN CURRENTLY ADVERTISED BY THE MODELS. PLAN TO HOLD MAX TEMPS IN THE TRIA AROUND 50...THOUGH IMMEDIATELY EAST-AND SOUTH OF THIS REGION...TEMPS SHOULD RECOVER INTO THE MID 50S. IF RAIN SPOTTY ACROSS THE SE...MAX TEMPS IN VICINITY OF CLINTON...FAYETTEVILLE AND GOLDSBORO MAY CLIMB INTO THE LOWER 60S. BEGIN TO SEE MODEL SOLUTIONS DIVERGE BY SATURDAY NIGHT WITH THE MORE PROGRESSIVE GFS SWINGS THE TROUGH ACROSS OUR REGION IN THE EVENING WITH PRECIP CHANCES DWINDLING OVERNIGHT. THE ECMWF IS MORE SLUGGISH...TRACKING AN UPPER LEVEL INTO THE MID ATLANTIC...WHICH MAINTAINS A CYCLONIC FLOW OVER OUR REGION...KEEPING SKIES OVERCAST AND A THREAT FOR RAIN CONTINUING ACROSS OUR EASTERN COUNTIES WELL INTO THE NIGHT. DIFFICULT TO SAY WITH A HIGH DEGREE OF CONFIDENCE WHICH MODEL IS MORE CORRECT AS THEY BOTH HAVE DISPLAYED DECENT RUN- TO-RUN CONTINUITY. WILL LEAN TOWARD THE PESSIMISTIC ECMWF FOR NOW AND SEE IF MODEL TREND ONE WAY BY TOMORROW. WITH THE LINGERING CLOUD COVERAGE AND WEAK LOW LEVEL CAA...HAVE RAISED MIN TEMPS UP A COUPLE OF DEGREES FROM PREVIOUS FORECAST. MIN TEMPS LOW-MID 40S. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 317 PM WEDNESDAY... SUNDAY...FORECAST CONFIDENCE LOW AS HUGE DISPARITY AMONG MODEL GUIDANCE THIS PERIOD. 12Z GFS DEPICTS A DRY AIR SURFACE RIDGE EXTENDING ACROSS THE REGION. THIS WOULD RESULT IN SUNNY AND COOL CONDITIONS. MEANWHILE THE 12Z ECMWF SLOWLY DRIFTS AN UPPER LEVEL ACROSS THE CHESAPEAKE BAY REGION...MAINTAINING OVERCAST SKIES...PATCHY LIGHT PRECIP AND COOL TEMPS ALONG WITH BRISK CONDITIONS OVER OUR COASTAL PLAIN DUE TO PRESENCE OF A COASTAL LOW OFFSHORE OF HATTERAS. PRESENTLY PREFER A WEAKER COUSIN OF THE 12Z ECMWF AS SOME SEPARATION OF THE JET STREAMS EXPECTED. THIS YIELDS BELOW NORMAL TEMPS WITH SOLID CHANCE FOR RAIN...MAINLY NORTH AND EAST. MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE REMAINS BELOW NORMAL AS MEDIUM RANGE MODEL GUIDANCE OFFERING VARIED SOLUTIONS. DOES APPEAR CERTAIN THAT WITH A L/W TROUGH OVER THE EASTERN U.S....HIGH TEMPS WILL AVERAGE AT LEAST ONE TO TWO CATEGORIES BELOW NORMAL. IN ADDITION...CLOUD COVERAGE WILL BE VARIABLE. GFS FAVORS LIGHT PRECIP MONDAY-MONDAY EVENING WITH THE PASSAGE OF A SOUTHERN STREAM SYSTEM...WHILE ECMWF FAVORS LATE TUESDAY INTO WEDNESDAY WHEN DIVES ANOTHER SIGNIFICANT S/W SEWD FROM THE GREAT LAKES TOWARDS THE SOUTHERN APPALACHIANS...SPINNING UP ANOTHER COASTAL LOW IN THE PROCESS. FOR NOW...KEPT POPS MINIMAL (NO WORSE THAN SLIGHT CHANCE/SMALL CHANCE). && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AS OF 145 AM THURSDAY... A COLD FRONT AND ASSOCIATED NORTHERLY WIND AND TRAILING DRIER AIR WILL CAUSE PRECEDING DENSE FOG AND LOW CLOUDS AT KRWI AND KFAY TO DISPERSE DURING THE NEXT SEVERAL HOURS...WHILE VFR CONDITIONS PREVAIL AT KRDU AND IN THE TRIAD. THE LOW LEVEL MOISTURE...SLOWEST TO DISPERSE AT KFAY...WILL LIKELY LIFT AND MORPH INTO A STRATOCUMULUS FIELD...THROUGH IFR-MVFR RANGE...BETWEEN 12-16Z AT KFAY...BEFORE SCATTERING AND LIFTING TO VFR THEREAFTER. AN OCCASIONAL MVFR CEILINGS WILL REMAIN POSSIBLE AT KFAY DURING THE AFTERNOON HOURS...WITH JUST A SCATTERING OF 3-5 THOUSAND FT STRATOCUMULUS BENEATH MID-HIGH LEVEL CEILINGS OTHERWISE AND ELSEWHERE. SURFACE WINDS WILL VEER FROM NW TO NE THROUGH THE MORNING...AND INCREASE BRIEFLY INTO THE 7-12 KT RANGE WITH GUSTS INTO THE MID-UPPER TEENS KTS AT EASTERN TERMINALS THROUGH 16Z...BEFORE LESSENING BY MIDDAY-EARLY AFTERNOON. OUTLOOK: SOUTHWEST FLOW ALOFT WILL GLIDE ATOP NORTHEASTERLY SURFACE FLOW AND RESULT IN PERIODS OF MVFR TO POSSIBLY IFR CEILINGS TONIGHT THROUGH SATURDAY...WITH THE LOWER CEILINGS MOST PROBABLE SAT MORNING. A FRONTAL SYSTEM AND ASSOCIATED CHANCE OF RAIN AND SUB-VFR CONDITIONS WILL AFFECT OUR REGION SAT AND SAT NIGHT...FOLLOWED BY HIGH PRESSURE AND NE FLOW THROUGH EARLY NEXT WEEK. THE NE FLOW COULD CAUSE SOME MVFR CEILINGS TO LINGER...ESPECIALLY AT EASTERN TERMINALS...THROUGH SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR NCZ011-026>028-039>041. DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NCZ042-043- 073>078-083>086-088-089. && $$ SYNOPSIS...MWS NEAR TERM...DJF/SEC SHORT TERM...WSS LONG TERM...WSS AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
111 AM EST THU DEC 4 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA THIS MORNING. SURFACE HIGH PRESSURE WILL BUILD IN... WHILE UPPER LEVEL DISTURBANCE MOVE ACROSS THE AREA THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1035 PM WEDNESDAY... COLD FRONT JUST ABOUT TO ENTER THE WESTERN PART OF THE CWA... AND SHOULD CROSS THE AREA OVERNIGHT. LACK OF UPPER LEVEL SUPPORT... DRY AIR THROUGH MUCH OF THE MID AND LOW LEVELS... EXCEPT FOR THE NEAR SURFACE LAYER AS SHOWN ON THE KGSO AND KMHX SOUNDINGS... WILL PRECLUDE ANY PRECIPITATION IN ASSOCIATION WITH ITS PASSAGE. PATCHY FOG... SOME LOCALLY DENSE... HAS FORMED AHEAD OF THE FRONT... BUT WILL BE SCOURED OUT ALONG WITH THE LOW CLOUDS OVER THE NEXT FEW HOURS AS MIXING INCREASES. UPPER LEVEL MOISTURE AND HIGH CLOUDS WILL REMAIN ACROSS THE AREA. LOWS IN THE UPPER 30S TO MID 40S NORTH TO SOUTH. THURSDAY AND THURSDAY NIGHT...A SERIES OF MID-LEVEL SHORTWAVES ARE FORECAST BY THE NAM AND THE GFS TO MOVE THROUGH CENTRAL NORTH CAROLINA IN THIS PERIOD. THE STRONGEST ON BOTH OF THOSE SETS OF GUIDANCE IS THURSDAY...COINCIDENT WITH A MID-LEVEL WAVE MOVING EAST OUT OF THE SOUTHERN PLAINS ON WATER VAPOR IMAGERY. DURING THIS TIME...OVER MOST OF CENTRAL NORTH CAROLINA THERE SHOULD BE 850MB THETA-E TROUGHINESS...SO OVERALL MOISTURE SHOULD BE LIMITED EXCEPT IN THE UPPER-LEVELS...AND POSSIBLY IN THE BOUNDARY LAYER OVER THE FAR SOUTH ALTHOUGH LIFT IS FORECAST TO BE MEAGER WITH BASICALLY 850MB DIVERGENCE AND LITTLE UPPER DIFFLUENCE. BY THURSDAY NIGHT... OVERALL MOISTURE STARTS TO INCREASE ON THE WEST SIDE OF THE SURFACE HIGH...WITH MORE OF THE MOISTURE INCREASE OVER THE MOUNTAINS INTO VIRGINIA. BOTH THE GFS AND THE NAM SHOW SLIGHT ISENTROPIC LIFT ON THE 300K SURFACE OVER THE NORTHWEST PIEDMONT THURSDAY NIGHT...WITH THE GFS AND NAM BUFR SOUNDINGS NOTING MOISTENING OF THE 850MB LAYER BUT WITH THE NAM SHOWING MORE MOISTENING OF THE MID-LAYERS. MOS GUIDANCE POPS ARE CREEPING UP INTO THE 30S ESPECIALLY FROM RALEIGH NORTH AND WEST...BUT GUIDANCE QPF STAYS JUST BELOW ZERO IN CENTRAL NORTH CAROLINA AND HRRR WRF GUIDANCE KEEPS THE APPEARANCE OF ANY MEASURABLE RAIN JUST TO OUR NORTH AND WEST. AVERAGING THE DRIER GFS AND THE MORE MOIST NAM WITH THE HRRR AND MOS GUIDANCE SUGGESTS A SLIGHT CHANCE OF RAIN OR SPRINKLES THURSDAY NIGHT MAINLY NORTH OF A LINE FROM ABOUT KEXX TO KTDF. 1000-850MB THICKNESSES WOULD SUPPORT HIGHS AT LEAST A CATEGORY ABOVE GUIDANCE FOR THURSDAY...BUT BEHIND THE FRONT AND WITH AT LEAST SOME PERIODS OF HIGH CLOUDS...WILL LEAN TOWARD THE MOS GUIDANCE VALUES WHICH ARE VERY CLOSE BETWEEN THE MET AND THE MAV...FOR HIGHS IN THE LOWER TO MID 50S OVERALL. COULD SEE THE WARMER MAV MINIMUM TEMPERATURES VERIFY THURSDAY NIGHT IF THERE ARE ENOUGH HIGH CLOUDS THROUGHOUT CENTRAL NORTH CAROLINA...BUT WITH A RELATIVE MINIMUM FOR A TIME THURSDAY EVENING ESPECIALLY EAST LEANED TOWARD THE WARMER MAV WEST AND TOWARD A BLEND OR THE COOLER VALUES EAST...37 TO 42. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 310 PM WEDNESDAY... FRIDAY...DRY AIR SURFACE RIDGE WILL EXTEND ACROSS THE FORECAST AREA EMANATING FROM A PARENT HIGH (1040+MB) OVER NORTHERN NEW ENGLAND. ALOFT A S/W WILL BE LIFTING NEWD FROM THE SOUTHERN PLAINS INTO THE LOWER OH VALLEY. WESTERLY FLOW IN THE MID-UPPER LEVELS WILL ADVECT MOISTURE FROM THIS SYSTEM INTO CENTRAL NC. THER COMBINATION OF A COOL STABLE AIR MASS NEAR THE SURFACE AND THE INCREASINGLY MOIST AIR MASS ALOFT SHOULD RESULT IN A VARIABLY CLOUDY AND SEASONABLY COOL DAY OVER OUR REGION. THICKER CLOUDS ANTICIPATED ACROSS THE NW SHOULD HOLD TEMPS BELOW 50 DEGREES. SOME POTENTIAL FOR PARTIAL/FILTERED SUN IN THE SE WHICH WILL ALLOW TEMPS TO WARM SOLIDLY INTO THE 50S. FRIDAY NIGHT...THE LOWER OH VALLEY SYSTEM WILL ADVANCE FARTHER EAST. INCREASING SOUTHERLY FLOW ABOVE THE SURFACE-BASED COOL DOME SHOULD INITIATE SOME OVERRUNNING OVER THE PIEDMONT LATE FRIDAY NIGHT/EARLY SATURDAY. CURRENTLY EXPECT ANY PRECIP TO BE SPOTTY AND LIGHT...MAINLY CONFINED TO AREAS WEST-NW OF HIGHWAY 1. MAY SEE AREAS OF FOG AS WELL. MIN TEMPS MID-UPPER 40S. SATURDAY AND SATURDAY NIGHT...S/W AND ATTENDANT SFC FRONT WILL CONTINUE TO LIFT E-NE. THIS WILL BRING AN INCREASING THREAT FOR RAIN ACROSS CENTRAL NC...ESPECIALLY LATE MORNING THROUGH EARLY EVENING. RESIDUAL CAD AIR MASS MAY HOLD ON LONGER IN THE FAVORED NW PIEDMONT THAN CURRENTLY ADVERTISED BY THE MODELS. PLAN TO HOLD MAX TEMPS IN THE TRIA AROUND 50...THOUGH IMMEDIATELY EAST-AND SOUTH OF THIS REGION...TEMPS SHOULD RECOVER INTO THE MID 50S. IF RAIN SPOTTY ACROSS THE SE...MAX TEMPS IN VICINITY OF CLINTON...FAYETTEVILLE AND GOLDSBORO MAY CLIMB INTO THE LOWER 60S. BEGIN TO SEE MODEL SOLUTIONS DIVERGE BY SATURDAY NIGHT WITH THE MORE PROGRESSIVE GFS SWINGS THE TROUGH ACROSS OUR REGION IN THE EVENING WITH PRECIP CHANCES DWINDLING OVERNIGHT. THE ECMWF IS MORE SLUGGISH...TRACKING AN UPPER LEVEL INTO THE MID ATLANTIC...WHICH MAINTAINS A CYCLONIC FLOW OVER OUR REGION...KEEPING SKIES OVERCAST AND A THREAT FOR RAIN CONTINUING ACROSS OUR EASTERN COUNTIES WELL INTO THE NIGHT. DIFFICULT TO SAY WITH A HIGH DEGREE OF CONFIDENCE WHICH MODEL IS MORE CORRECT AS THEY BOTH HAVE DISPLAYED DECENT RUN- TO-RUN CONTINUITY. WILL LEAN TOWARD THE PESSIMISTIC ECMWF FOR NOW AND SEE IF MODEL TREND ONE WAY BY TOMORROW. WITH THE LINGERING CLOUD COVERAGE AND WEAK LOW LEVEL CAA...HAVE RAISED MIN TEMPS UP A COUPLE OF DEGREES FROM PREVIOUS FORECAST. MIN TEMPS LOW-MID 40S. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 317 PM WEDNESDAY... SUNDAY...FORECAST CONFIDENCE LOW AS HUGE DISPARITY AMONG MODEL GUIDANCE THIS PERIOD. 12Z GFS DEPICTS A DRY AIR SURFACE RIDGE EXTENDING ACROSS THE REGION. THIS WOULD RESULT IN SUNNY AND COOL CONDITIONS. MEANWHILE THE 12Z ECMWF SLOWLY DRIFTS AN UPPER LEVEL ACROSS THE CHESAPEAKE BAY REGION...MAINTAINING OVERCAST SKIES...PATCHY LIGHT PRECIP AND COOL TEMPS ALONG WITH BRISK CONDITIONS OVER OUR COASTAL PLAIN DUE TO PRESENCE OF A COASTAL LOW OFFSHORE OF HATTERAS. PRESENTLY PREFER A WEAKER COUSIN OF THE 12Z ECMWF AS SOME SEPARATION OF THE JET STREAMS EXPECTED. THIS YIELDS BELOW NORMAL TEMPS WITH SOLID CHANCE FOR RAIN...MAINLY NORTH AND EAST. MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE REMAINS BELOW NORMAL AS MEDIUM RANGE MODEL GUIDANCE OFFERING VARIED SOLUTIONS. DOES APPEAR CERTAIN THAT WITH A L/W TROUGH OVER THE EASTERN U.S....HIGH TEMPS WILL AVERAGE AT LEAST ONE TO TWO CATEGORIES BELOW NORMAL. IN ADDITION...CLOUD COVERAGE WILL BE VARIABLE. GFS FAVORS LIGHT PRECIP MONDAY-MONDAY EVENING WITH THE PASSAGE OF A SOUTHERN STREAM SYSTEM...WHILE ECMWF FAVORS LATE TUESDAY INTO WEDNESDAY WHEN DIVES ANOTHER SIGNIFICANT S/W SEWD FROM THE GREAT LAKES TOWARDS THE SOUTHERN APPALACHIANS...SPINNING UP ANOTHER COASTAL LOW IN THE PROCESS. FOR NOW...KEPT POPS MINIMAL (NO WORSE THAN SLIGHT CHANCE/SMALL CHANCE). && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AS OF 645 PM WEDNESDAY... 24 HOUR TAF PERIOD: PRETTY LOW CONFIDENCE FORECAST CONCERNING AVIATION CONDITIONS OVER THE NEXT 24 HOURS. A FRONTAL SYSTEM JUST TO THE NORTHWEST OF THE AREA AND THE MODELS HANDLING OF THIS SYSTEM IS VERY MUCH IN QUESTION. IN THE VERY NEAR TERM EXPECT TRIAD TERMINALS TO HAVE SOME VISIBILITY PROBLEMS BEFORE FRONTAL PASSAGE WHICH AT THIS HOUR IS STILL ALONG THE FOOTHILLS OF NC AND VA. WINDS WILL BE LIGHT AND VARIABLE BUT ONCE THE FRONT GOES THROUGH SOMETIME AROUND 2 OR 3Z...ANY FOG THAT FORMS IN THE MEANTIME SHOULD QUICKLY DISSIPATE. THE FRONT WILL TAKE LONGER TO REACH EASTERN TERMINALS AND THUS AN EXTENDED PERIOD OF DECREASED VISIBILITIES THROUGH 7 OR 8 Z WILL BE POSSIBLE. EVENTUALLY THE FRONT WILL MAKE IT THROUGH ALL TERMINALS AND WINDS WILL SWING AROUND TO NORTHEASTERLY FOR THURSDAY AT 5-10 KTS. THERE WILL REMAIN A QUESTION OF WHETHER OR NOT CEILINGS WILL BE MVFR OR VFR THURSDAY AFTERNOON AS THE NAM MODEL INDICATES LOWER CEILINGS PROBABLE BUT THE GFS KEEPS CEILINGS IN THE 5 KFT VICINITY. WILL WAIT FOR FURTHER GUIDANCE TO COME IN AND COVER FOR NOW WITH SCATTERED MVFR CEILINGS BUT THESE COULD BE INCREASED TO BROKEN OR OVERCAST WITH THE NEXT FORECAST PACKAGE. LONG TERM: THE LONG TERM WILL ENCOMPASS AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH SATURDAY THE MOST PESSIMISTIC DAY FOR AVIATION CONDITIONS. THESE WILL CONTINUE INTO SUNDAY BEFORE MODEL SOLUTIONS DIVERGE INTO EARLY NEXT WEEK...RESULTING IN A LOW CONFIDENCE FORECAST FOR THE EARLY PART OF NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR NCZ011-026>028-039>041. DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NCZ042-043- 073>078-083>086-088-089. && $$ SYNOPSIS...DJF/SEC NEAR TERM...DJF/SEC SHORT TERM...WSS LONG TERM...WSS AVIATION...RE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
924 PM CST FRI DEC 5 2014 .UPDATE... ISSUED AT 923 PM CST FRI DEC 5 2014 FOR LATE EVENING UPDATE MAIN CONCERN WAS PRECIPITATION OVER THE FAR SOUTHWEST. LATEST HIGH-RES MODELS WERE HAVING SOME TROUBLE ON PLACEMENT OF PRECIPITATION THIS EVENING...BUT REGIONAL RADAR MOSAIC ALONG WITH BOWMAN ARB RADAR INDICATED VERY LIGHT PRECIPITATION SHIFTING TOWARDS WEST CENTRAL AND SOUTHWEST NORTH DAKOTA. THEREFORE...HAVE SPREAD LOW POPS THROUGH THE SOUTHWEST. NEXT CONCERN WAS PRECIP TYPE AS SOME WARMER AIR ALOFT IS STARTING TO PUSH TOWARDS THE FAR SOUTHWEST. WITH THIS...HAVE ADDED THE MENTION OF POSSIBLE SLEET/FREEZING RAIN...ALTHOUGH CHANCES AND COVERAGE WILL BE VERY LOW. ONLY OTHER CHANGE FOR UPDATE WAS DROPPING LOW TEMPERATURES A BIT OVER THE NORTHWEST/NORTH CENTRAL AS OBBS JUST NORTH OF THE CANADIAN BORDER HAVE ALREADY DIPPED DOWN TOWARDS ZERO. UPDATES HAVE BEEN SENT. UPDATE ISSUED AT 621 PM CST FRI DEC 5 2014 MAIN CHANGE FOR EARLY EVENING UPDATE WAS TO INCREASE CLOUD COVER ACROSS ALL AREAS EXCEPT FAR SOUTH CENTRAL/JAMES RIVER VALLEY AS BROAD AREA CONTINUES TO SHIFT SOUTHEAST. WILL HAVE TO KEEP AN EYE ON TEMPERATURES THROUGH THE EVENING AS WHEREVER THERE ARE BREAKS IN THE CLOUD COVER OVER THE NORTH...THE TEMPERATURE HAS DROPPED QUICKLY. UPDATES HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 CURRENTLY...HIGH PRESSURE OVER NORTHWEST NORTH DAKOTA THIS EARLY AFTERNOON IS FORECAST TO MOVE EAST ACROSS THE FORECAST AREA TONIGHT. IFR STRATUS REMAINS OVER NORTHWEST NORTH DAKOTA FROM CROSBY AND WILLISTON...EAST TO STANLEY...BUT HAVING A HARD TIME MAKING IT MUCH FARTHER EAST THIS AFTERNOON. TEMPERATURES RANGED FROM THE UPPER TEENS-LOW 20S NORTH TO UPPER 20S-LOW 30S SOUTH. MAIN CONCERN FOR THE SHORT TERM PERIOD IS STRATUS/FOG POSSIBILITIES AND POSSIBLE LIGHT PRECIPITATION ACROSS THE NORTH. THE 05 DEC 12 UTC NAM AND MESOSCALE MODELS HAVE BEEN HINTING AT A BAND OF LIGHT PRECIPITATION MOVING ACROSS NORTHERN NORTH DAKOTA LATE TONIGHT INTO SATURDAY MORNING. THE 18 UTC NAM HAS DISPLACED THE PRECIPITATION FARTHER SOUTH...BUT RAP/HRRR HAVE BEEN PRETTY CONSISTENT IN KEEPING VERY LIGHT PRECIPITATION ACROSS THE NORTH. HAVE ADDED SOME SLIGHT CHANCE POPS NORTHWEST AND NORTH CENTRAL LATER THIS EVENING INTO SATURDAY MORNING...TAPERING TO ONLY FLURRIES AS PRECIPITATION MOVES FROM NORTH CENTRAL INTO NORTHEAST ND. HAVE KEPT PRECIPITATION ALL SNOW AS IT LOOKS LIKE THE WARMER TEMPERATURES ALOFT DO NOT ARRIVE UNTIL BEST FORCING HAS ALREADY PASSED...THUS PRECIP SHOULD REMAIN ALL SNOW. MESOSCALE MODELS CONTINUE TO SHOW INCREASING LOW LEVEL MOISTURE ACROSS THE NORTH AND EAST THIS AFTERNOON AND THIS EVENING...THEN POSSIBLY SHIFTING MORE TO THE SOUTHWEST LATER TONIGHT AS SOUTHEAST FLOW KICKS IN ON THE BACK SIDE OF THE SURFACE HIGH. HAVE OPTED TO MENTION PATCHY FOG TONIGHT AS RAP BUFR SOUNDINGS DO SUGGEST FOG MOST AREAS. ALSO HAVE BUMPED UP SKY COVER LATE EVENING THROUGH SATURDAY MORNING. TEMPERATURES ALSO TRICKY AS WE WILL LIKELY SEE A QUICK DROP THIS EVENING EAST WITH RISING TEMPERATURES LATE. PERHAPS A QUICK DROP CENTRAL/WEST WITH RISING TEMPERATURES LATE EVENING INTO THE OVERNIGHT AND THEN DROPPING OFF BY MORNING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 SATURDAY NIGHT THROUGH SUNDAY NIGHT...AN UPPER LEVEL LOW/SHARP TROUGH WITH AN ASSOCIATED SURFACE COLD FRONT WILL PUSH ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY INTO SUNDAY NIGHT. SOUTH TO SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL ALLOW FOR WARMING THROUGH SUNDAY MORNING. THE H85 BAROCLINIC ZONE BEGINS TO PUSH ACROSS THE FAR WEST BY 18Z AND THEN SHIFTS INTO CENTRAL NORTH DAKOTA SUNDAY AFTERNOON/EVENING. STILL SOME THREAT OF A WINTRY MIX ACROSS NORTHERN NORTH DAKOTA...BUT IT APPEARS THE BETTER CHANCE FOR PRECIPITATION MAY OCCUR SUNDAY EVENING INTO SUNDAY NIGHT ACROSS NORTHERN NORTH DAKOTA...ASSOCIATED WITH A WEAK/NARROW TROWAL PER GFS H7-H5 EQUIVALENT POTENTIAL TEMPERATURE. AMOUNTS LOOK VERY LIGHT...PERHAPS A TENTH OR TWO OF AN INCH OF SNOW. WEST TO NORTHWEST WINDS INCREASE IN THE WEST DURING THE AFTERNOON WITH THE STRONGEST WINDS NOT ARRIVING UNTIL SUNDAY NIGHT FOR CENTRAL NORTH DAKOTA. EXPECT 20 TO 35MPH WINDS DEVELOPING BEHIND THIS SYSTEM. WITH LIMITED SNOW SHOWERS AND QPF...AT THIS TIME HAVE NOT MENTIONED ANY BLOWING SNOW. MONDAY THROUGH FRIDAY...BRISK NORTHWEST WINDS CONTINUE DURING THE DAY MONDAY BUT ABATE MONDAY EVENING. COLDER MONDAY AFTERNOON WITH HIGHS 20 NORTHEAST TO MID 30S FAR SOUTHWEST. THEREAFTER A PROGRESSIVE PATTERN ENSUES WITH NO SIGNIFICANT SHORTWAVES FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. A WARMING TREND IS STILL IN THE FORECAST WITH HIGHS 35F TO 45F WEDNESDAY THROUGH FRIDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 621 PM CST FRI DEC 5 2014 IFR CIGS WILL CONTINUE OVER NORTHERN NORTH DAKOTA THROUGH MUCH OF THE NIGHT AFFECTING THE KISN AND KMOT TERMINALS. FURTHER SOUTH...MID LEVEL CLOUD COVER WILL REMAIN...THOUGH LCL FOG MAY DEVELOP OVERNIGHT INTO EARLY SATURDAY AFFECTING KDIK-KBIS-KJMS. AN ...AMD NOT SKED... HAS BEEN POSTED TO THE KBIS TAF DUE TO PROBLEMS WITH THE VISIBILITY SENSOR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SHORT TERM...TWH LONG TERM...KS AVIATION...JJS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
629 PM CST FRI DEC 5 2014 .UPDATE... ISSUED AT 621 PM CST FRI DEC 5 2014 MAIN CHANGE FOR EARLY EVENING UPDATE WAS TO INCREASE CLOUD COVER ACROSS ALL AREAS EXCEPT FAR SOUTH CENTRAL/JAMES RIVER VALLEY AS BROAD AREA CONTINUES TO SHIFT SOUTHEAST. WILL HAVE TO KEEP AN EYE ON TEMPERATURES THROUGH THE EVENING AS WHEREVER THERE ARE BREAKS IN THE CLOUD COVER OVER THE NORTH...THE TEMPERATURE HAS DROPPED QUICKLY. UPDATES HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 CURRENTLY...HIGH PRESSURE OVER NORTHWEST NORTH DAKOTA THIS EARLY AFTERNOON IS FORECAST TO MOVE EAST ACROSS THE FORECAST AREA TONIGHT. IFR STRATUS REMAINS OVER NORTHWEST NORTH DAKOTA FROM CROSBY AND WILLISTON...EAST TO STANLEY...BUT HAVING A HARD TIME MAKING IT MUCH FARTHER EAST THIS AFTERNOON. TEMPERATURES RANGED FROM THE UPPER TEENS-LOW 20S NORTH TO UPPER 20S-LOW 30S SOUTH. MAIN CONCERN FOR THE SHORT TERM PERIOD IS STRATUS/FOG POSSIBILITIES AND POSSIBLE LIGHT PRECIPITATION ACROSS THE NORTH. THE 05 DEC 12 UTC NAM AND MESOSCALE MODELS HAVE BEEN HINTING AT A BAND OF LIGHT PRECIPITATION MOVING ACROSS NORTHERN NORTH DAKOTA LATE TONIGHT INTO SATURDAY MORNING. THE 18 UTC NAM HAS DISPLACED THE PRECIPITATION FARTHER SOUTH...BUT RAP/HRRR HAVE BEEN PRETTY CONSISTENT IN KEEPING VERY LIGHT PRECIPITATION ACROSS THE NORTH. HAVE ADDED SOME SLIGHT CHANCE POPS NORTHWEST AND NORTH CENTRAL LATER THIS EVENING INTO SATURDAY MORNING...TAPERING TO ONLY FLURRIES AS PRECIPITATION MOVES FROM NORTH CENTRAL INTO NORTHEAST ND. HAVE KEPT PRECIPITATION ALL SNOW AS IT LOOKS LIKE THE WARMER TEMPERATURES ALOFT DO NOT ARRIVE UNTIL BEST FORCING HAS ALREADY PASSED...THUS PRECIP SHOULD REMAIN ALL SNOW. MESOSCALE MODELS CONTINUE TO SHOW INCREASING LOW LEVEL MOISTURE ACROSS THE NORTH AND EAST THIS AFTERNOON AND THIS EVENING...THEN POSSIBLY SHIFTING MORE TO THE SOUTHWEST LATER TONIGHT AS SOUTHEAST FLOW KICKS IN ON THE BACK SIDE OF THE SURFACE HIGH. HAVE OPTED TO MENTION PATCHY FOG TONIGHT AS RAP BUFR SOUNDINGS DO SUGGEST FOG MOST AREAS. ALSO HAVE BUMPED UP SKY COVER LATE EVENING THROUGH SATURDAY MORNING. TEMPERATURES ALSO TRICKY AS WE WILL LIKELY SEE A QUICK DROP THIS EVENING EAST WITH RISING TEMPERATURES LATE. PERHAPS A QUICK DROP CENTRAL/WEST WITH RISING TEMPERATURES LATE EVENING INTO THE OVERNIGHT AND THEN DROPPING OFF BY MORNING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 SATURDAY NIGHT THROUGH SUNDAY NIGHT...AN UPPER LEVEL LOW/SHARP TROUGH WITH AN ASSOCIATED SURFACE COLD FRONT WILL PUSH ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY INTO SUNDAY NIGHT. SOUTH TO SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL ALLOW FOR WARMING THROUGH SUNDAY MORNING. THE H85 BAROCLINIC ZONE BEGINS TO PUSH ACROSS THE FAR WEST BY 18Z AND THEN SHIFTS INTO CENTRAL NORTH DAKOTA SUNDAY AFTERNOON/EVENING. STILL SOME THREAT OF A WINTRY MIX ACROSS NORTHERN NORTH DAKOTA...BUT IT APPEARS THE BETTER CHANCE FOR PRECIPITATION MAY OCCUR SUNDAY EVENING INTO SUNDAY NIGHT ACROSS NORTHERN NORTH DAKOTA...ASSOCIATED WITH A WEAK/NARROW TROWAL PER GFS H7-H5 EQUIVALENT POTENTIAL TEMPERATURE. AMOUNTS LOOK VERY LIGHT...PERHAPS A TENTH OR TWO OF AN INCH OF SNOW. WEST TO NORTHWEST WINDS INCREASE IN THE WEST DURING THE AFTERNOON WITH THE STRONGEST WINDS NOT ARRIVING UNTIL SUNDAY NIGHT FOR CENTRAL NORTH DAKOTA. EXPECT 20 TO 35MPH WINDS DEVELOPING BEHIND THIS SYSTEM. WITH LIMITED SNOW SHOWERS AND QPF...AT THIS TIME HAVE NOT MENTIONED ANY BLOWING SNOW. MONDAY THROUGH FRIDAY...BRISK NORTHWEST WINDS CONTINUE DURING THE DAY MONDAY BUT ABATE MONDAY EVENING. COLDER MONDAY AFTERNOON WITH HIGHS 20 NORTHEAST TO MID 30S FAR SOUTHWEST. THEREAFTER A PROGRESSIVE PATTERN ENSUES WITH NO SIGNIFICANT SHORTWAVES FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. A WARMING TREND IS STILL IN THE FORECAST WITH HIGHS 35F TO 45F WEDNESDAY THROUGH FRIDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 621 PM CST FRI DEC 5 2014 IFR CIGS WILL CONTINUE OVER NORTHERN NORTH DAKOTA THROUGH MUCH OF THE NIGHT AFFECTING THE KISN AND KMOT TERMINALS. FURTHER SOUTH...MID LEVEL CLOUD COVER WILL REMAIN...THOUGH LCL FOG MAY DEVELOP OVERNIGHT INTO EARLY SATURDAY AFFECTING KDIK-KBIS-KJMS. AN ...AMD NOT SKED... HAS BEEN POSTED TO THE KBIS TAF DUE TO PROBLEMS WITH THE VISIBILITY SENSOR. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SHORT TERM...TWH LONG TERM...KS AVIATION...JJS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
311 PM EST THU DEC 4 2014 .SYNOPSIS... SERIES OF LOW PRESSURE WAVES CROSS INTO THE WEEKEND. HIGH PRESSURE SUNDAY. COLD FRONT EARLY NEXT WEEK MAY BE FOLLOWED A BY LONGER PERIOD OF HIGH PRESSURE. && .NEAR TERM /THROUGH FRIDAY/... PRECIP EXPANDING NE A BIT QUICKER THAN PREVIOUS FORECAST. STILL A SIGNIFICANT DRY LAYER IN THE LOWER LAYERS TO OVERCOME...BUT IT WONT TAKE LONG FOR THIS TO ERODE ONCE THE PRECIP MOVES IN. EXCEPTION BEING ACROSS SE OH AND N WV WHERE THE DRY LAYER IS A BIT MORE ROBUST. USED LATEST HRRR FOR TIMING OF HIGH POPS IN THRU THIS AFTERNOON AND EVENING. ALSO INSERTED A BRIEF PERIOD OF SLEET MIXING IN ON THE LEADING EDGE ACROSS NE KY/ W WV/ AND SE OH. THIS MIX CAN BE EXPECTED IN THE N MOUNTAINS AS WELL. ONCE THIS WAVE MOVES BY...CWA LEFT WITH WARM FRONT THIS EVENING WITH SHRA REGIME MAINLY N HALF OF CWA. WILL WATCH FOR A SURFACE LOW TO ORGANIZE OVER THE TN VALLEY WITH A WARM FRONT APPENDAGE DEVELOPING INTO AREA LATE TONIGHT. THIS WILL INCREASE THE COVERAGE OF PRECIP HEADING INTO FRIDAY AS THE WARM FRONT SLOWLY SHIFTS INTO SE OH. THERE MAY BE AN EXTENDED LULL IN PRECIP ACROSS SW VA AND SE WV FRIDAY WITH THESE AREAS IN WARM SECTOR. AFTER INTERROGATING HI RES MODELS AND SREF PROBS...ELECTED NOT TO EXPAND THE FRZ RA ADVISORY TO RANDOLPH. ASIDE FROM A BRIEF MIX LATER THIS AFTERNOON...EXPECT BULK OF PRECIP TONIGHT TO FALL AS RAIN. THERE COULD BE A LITTLE FRZ RA ACROSS FAR EASTERN RANDOLPH BUT DEFINITELY NOT A COUNTY WIDE AVG. IN FACT...THERE IS CONCERN THAT TEMPS MAY WARM ENOUGH TONIGHT FOR RAIN EVEN OVER POCAHONTAS COUNTY. HI RES NAM IS BY FAR COOLEST OF THE MODELS...KEEPING A SUB FRZ THIN LAYER AROUND H9. ELEVATIONS ABOVE 3 KFT SHOULD GET INTO WARM LAYER SUCH THAT RISING TEMPS ARE EXPECTED TONIGHT. IT SHOULD BE QUITE MILD TOMORROW IN WARM SECTOR WHERE MID TO UPPER 50S WERE CODED UP ACROSS SW VA UP TO I64. DOWNSLOPING COMPONENT PROBABLY ALSO SENDS EKN INTO THE LOW 50S. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... VERY FEW CHANGES TO THE SHORT TERM FORECAST. KEEP THE HIGH POPS GOING THROUGH THE SATURDAY PERIOD...DECREASING INTO SATURDAY NIGHT WITH THE PASSAGE OF THE SURFACE LOW AND ACCOMPANYING UPPER LEVEL TROUGH AXIS. EXPECTING A BATCH OF HEAVIER RAIN TO COME THROUGH IN THE 09Z SATURDAY TIME FRAME WITH 850MB THETA E CONVERGENCE PEAKING. AFTER ALL IS SAID AND DONE...1-1.5 INCHES OF RAIN IS NOT OUT OF THE QUESTION BY SATURDAY NIGHT WHEN THE SYSTEM EXITS. CLEARING SHOULD OCCUR QUICKLY SUNDAY AS THE FLOW WILL NOT GO TO ITS TYPICAL NORTHWEST TRAJECTORY. LOOKING AT A NORTH NORTHEASTERLY LOW LEVEL FLOW AND QUICK DRYING ALOFT...SO SHOULD SEE SOME SUN ON SUNDAY. CIRRUS FROM THE NEXT SYSTEM FOR THE LONG TERM PERIOD WILL BE ON ITS WAY IN QUICKLY AS IT ORGANIZES TO THE WEST. AIRMASS BEHIND THE LOW PRESSURE SYSTEM WILL DROP HIGH TEMPERATURES BACK INTO THE 40S FOR THE LOWLANDS...30S FOR THE MOUNTAINS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MODELS INDICATE A HIGH PRESSURE MOVING OVER NEW ENGLAND...EXTENDING SOUTHWEST INTO WV SUNDAY NIGHT. ALTHOUGH A COLD AIR MASS WILL BE IN PLACE...THIS PATTERN WOULD BRING EAST TO SOUTHEAST FLOW...CAPABLE TO PRODUCE DOWNSLOPING WARMING ACROSS THE LOWLANDS SUNDAY NIGHT. INCREASED FEW DEGREES FROM HPC GUIDANCE ACCORDINGLY. FOR MONDAY...BUFKIT SOUNDINGS SHOW DRY AIR ALOFT WITH LIMITED MOISTURE IN THE VERY LOW LEVELS WHILE A H500 WEAK SHORTWAVE CROSSES THE AREA. KEPT LOW CHANCE POPS WITH THIS FEATURE...MORE ALONG THE GFS SOLUTION. THE ECMWF BRINGS STRONG COLD AIR ADVECTION FOR THE SAME TIME PERIOD WITH SUCH A WEAK WAVE. BELIEVE ECMWF IS OVERDOING CAA SO PREFERRED THE GFS. BY MONDAY NIGHT FLOW IN THE LOW LEVELS TURN NORTHWEST WITH SOME CAA FROM BOTH MODELS. FIGURE A GOOD SET UP FOR UPSLOPE PCPN. THE GFS BRINGS THE 0C LEVEL AROUND THE NORTHEAST MOUNTAINS WHILE IN THE ECMWF...THE 0C LINE GOES WAY SOUTH OF THE AREA. WENT WITH A BLEND SOLUTION EXPECTING CHANCE POPS WITH FEW SNOW SHOWERS OR MIX PCPN OVER THE MOST FAVORABLE UPSLOPE AREAS...AND RAIN ELSEWHERE. PCPN IS EXPECTED TO TAMPER OFF ON TUESDAY KEEPING CHANCE POPS OVER THE EASTERN MOUNTAINS ESPECIALLY WITH THE UPSLOPE COMPONENT AND DRY WEATHER SPREADING FROM SOUTHEAST OH...EAST. DRY WEATHER EXPECTED THROUGH THE REST OF THE PERIOD AS A HIGH PRESSURE BUILDS IN. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... AN UPPER LEVEL SYSTEM COMBINED WITH A WARM FRONTAL BOUNDARY WILL ALLOW PRECIP TO OVERSPREAD MOST OF THE AREA THRU THE EVENING. THIS WILL MAINLY BE IN THE FORM OF RA...SAVE FOR A BRIEF PERIOD OF PL POSSIBLY ON THE FRONT END OF THE PRECIP THIS AFTERNOON. EXPECT VSBY TO LOWER INTO MVFR AS THE PRECIP MOVES ALONG WITH A GRADUAL LOWERING OF CIGS INTO MVFR HEADING INTO THIS EVENING. ONCE THIS UPPER LEVEL SYSTEM PASSES...EXPECT A SHRA REGIME TO TAKE HOLD WITH A WARM FRONTAL BOUNDARY LINGERING. AGAIN...RA EXPECTED TO BE DOMINATE PRECIP TYPE AT ALL TAF SITES. SOME FRZ RA OR PL MIXTURE IS EXPECTED IN THE N MOUNTAINS THIS EVENING. CIGS AND VSBY EXPECTED TO LOWER INTO IFR TONIGHT FOR MOST TAF SITES WITH EKN HOLDING OUT THE LONGEST. A SFC LOW WILL ORGANIZE OVER TN VALLEY...WITH ANOTHER WARM FRONT DEVELOPING INTO THE REGION FOR FRIDAY. THIS WILL INCREASE THE COVERAGE OF PRECIP ONCE AGAIN...WITH MOST OF THE RA N AND W OF A HTS/CRW/CKB LINE. CONDITIONS SHOULD IMPROVE FOR KCRW AND PERHAPS KBKW ONCE INTO THE WARM SECTOR WHILE IFR CONDITIONS IN RA PERSIST ELSEWHERE. SFC FLOW WILL BE LIGHT AND VARIABLE...MAINLY FROM THE E. LIGHT W FLOW ALOFT WILL BECOME LIGHT SW TONIGHT...INCREASING A BIT TOWARD DAWN FRI. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS IN RAIN MAY VARY OVERNIGHT TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H M M M M M H H H H L HTS CONSISTENCY H H H L L L H H L L L L BKW CONSISTENCY H H M H H H H H H H H M EKN CONSISTENCY H H H H H M M M M H H M PKB CONSISTENCY H H M M M M M M M H H M CKB CONSISTENCY H H H H H H M M M H H H AFTER 18Z FRIDAY... IFR POSSIBLE OVERNIGHT FRIDAY INTO THE WEEKEND IN RAIN...WITH FREEZING RAIN LIKELY IN THE NORTHERN MOUNTAINS...MAINLY E OF THE CHEAT RIDGE...INTO FRIDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY FROM 8 PM THIS EVENING TO 11 AM EST FRIDAY FOR WVZ046. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30/26 NEAR TERM...30 SHORT TERM...26 LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
202 PM EST THU DEC 4 2014 .SYNOPSIS... SERIES OF LOW PRESSURE WAVES CROSS INTO THE WEEKEND. HIGH PRESSURE SUNDAY. COLD FRONT EARLY NEXT WEEK MAY BE FOLLOWED A BY LONGER PERIOD OF HIGH PRESSURE. && .NEAR TERM /THROUGH FRIDAY/... PRECIP EXPANDING NE A BIT QUICKER THAN PREVIOUS FORECAST. STILL A SIGNIFICANT DRY LAYER IN THE LOWER LAYERS TO OVERCOME...BUT IT WONT TAKE LONG FOR THIS TO ERODE ONCE THE PRECIP MOVES IN. EXCEPTION BEING ACROSS SE OH AND N WV WHERE THE DRY LAYER IS A BIT MORE ROBUST. USED LATEST HRRR FOR TIMING OF HIGH POPS IN THRU THIS AFTERNOON AND EVENING. ALSO INSERTED A BRIEF PERIOD OF SLEET MIXING IN ON THE LEADING EDGE ACROSS NE KY/ W WV/ AND SE OH. THIS MIX CAN BE EXPECTED IN THE N MOUNTAINS AS WELL. ONCE THIS WAVE MOVES BY...CWA LEFT WITH WARM FRONT THIS EVENING WITH SHRA REGIME MAINLY N HALF OF CWA. WILL WATCH FOR A SURFACE LOW TO ORGANIZE OVER THE TN VALLEY WITH A WARM FRONT APPENDAGE DEVELOPING INTO AREA LATE TONIGHT. THIS WILL INCREASE THE COVERAGE OF PRECIP HEADING INTO FRIDAY AS THE WARM FRONT SLOWLY SHIFTS INTO SE OH. THERE MAY BE AN EXTENDED LULL IN PRECIP ACROSS SW VA AND SE WV FRIDAY WITH THESE AREAS IN WARM SECTOR. AFTER INTERROGATING HI RES MODELS AND SREF PROBS...ELECTED NOT TO EXPAND THE FRZ RA ADVISORY TO RANDOLPH. ASIDE FROM A BRIEF MIX LATER THIS AFTERNOON...EXPECT BULK OF PRECIP TONIGHT TO FALL AS RAIN. THERE COULD BE A LITTLE FRZ RA ACROSS FAR EASTERN RANDOLPH BUT DEFINITELY NOT A COUNTY WIDE AVG. IN FACT...THERE IS CONCERN THAT TEMPS MAY WARM ENOUGH TONIGHT FOR RAIN EVEN OVER POCAHONTAS COUNTY. HI RES NAM IS BY FAR COOLEST OF THE MODELS...KEEPING A SUB FRZ THIN LAYER AROUND H9. ELEVATIONS ABOVE 3 KFT SHOULD GET INTO WARM LAYER SUCH THAT RISING TEMPS ARE EXPECTED TONIGHT. IT SHOULD BE QUITE MILD TOMORROW IN WARM SECTOR WHERE MID TO UPPER 50S WERE CODED UP ACROSS SW VA UP TO I64. DOWNSLOPING COMPONENT PROBABLY ALSO SENDS EKN INTO THE LOW 50S. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... ACTIVE WEATHER IN THE SHORT TERM PERIOD. WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE AREA ON FRIDAY. WITH COLDER AIR EXPECTED TO BE AT THE SURFACE ALONG THE HIGHER TERRAIN...AND THE WARMER AIR MOVING IN ALOFT...THIS WILL SET UP A SCENARIO OF LIGHT FREEZING RAIN EARLY FRIDAY ACROSS NORTHERN MOUNTAINS. THIS WILL TAPER OFF BY LATE MORNING/EARLY AFTERNOON...AS LOW PRESSURE WAVE MOVES INTO THE REGION...AND WARMER AIR IS ABLE TO ERODE AWAY THE COLDER SURFACE TEMPERATURES...EVENTUALLY CHANGING ALL PRECIP TO RAIN. LOTS OF MOISTURE EXPECTED ACROSS THE AREA DURING THIS EVENT WITH A GOOD TAP OF GULF MOISTURE...WITH PW VALUES PROGGED TO RISE TO AROUND 1.1 TO 1.2 INCHES. EXPECTING A DECENT SHOT OF RAIN...PARTICULARLY ACROSS THE NORTH...WHERE LOW IS EXPECTED TO TRACK. AT THIS POINT...EXPECTING A GENERAL 1 TO 1.3 INCHES OF QPF. AT THIS POINT...ISSUES ON AREA WATERWAYS IS NOT EXPECTED...BUT THIS WILL NEED TO BE MONITORED AS THE EVENT APPROACHES. LOW WILL MOVE OFF TO THE EAST SATURDAY INTO SUNDAY...WITH GRADUALLY DRYING WEATHER FROM WEST TO EAST AS IT DOES SO. COULD BE SOME -DZ OR -FZDZ AT THE END OF THE EVENT AS WARMER AIR WORKS ITS WAY IN ALOFT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MODELS INDICATE A HIGH PRESSURE MOVING OVER NEW ENGLAND...EXTENDING SOUTHWEST INTO WV SUNDAY NIGHT. ALTHOUGH A COLD AIR MASS WILL BE IN PLACE...THIS PATTERN WOULD BRING EAST TO SOUTHEAST FLOW...CAPABLE TO PRODUCE DOWNSLOPING WARMING ACROSS THE LOWLANDS SUNDAY NIGHT. INCREASED FEW DEGREES FROM HPC GUIDANCE ACCORDINGLY. FOR MONDAY...BUFKIT SOUNDINGS SHOW DRY AIR ALOFT WITH LIMITED MOISTURE IN THE VERY LOW LEVELS WHILE A H500 WEAK SHORTWAVE CROSSES THE AREA. KEPT LOW CHANCE POPS WITH THIS FEATURE...MORE ALONG THE GFS SOLUTION. THE ECMWF BRINGS STRONG COLD AIR ADVECTION FOR THE SAME TIME PERIOD WITH SUCH A WEAK WAVE. BELIEVE ECMWF IS OVERDOING CAA SO PREFERRED THE GFS. BY MONDAY NIGHT FLOW IN THE LOW LEVELS TURN NORTHWEST WITH SOME CAA FROM BOTH MODELS. FIGURE A GOOD SET UP FOR UPSLOPE PCPN. THE GFS BRINGS THE 0C LEVEL AROUND THE NORTHEAST MOUNTAINS WHILE IN THE ECMWF...THE 0C LINE GOES WAY SOUTH OF THE AREA. WENT WITH A BLEND SOLUTION EXPECTING CHANCE POPS WITH FEW SNOW SHOWERS OR MIX PCPN OVER THE MOST FAVORABLE UPSLOPE AREAS...AND RAIN ELSEWHERE. PCPN IS EXPECTED TO TAMPER OFF ON TUESDAY KEEPING CHANCE POPS OVER THE EASTERN MOUNTAINS ESPECIALLY WITH THE UPSLOPE COMPONENT AND DRY WEATHER SPREADING FROM SOUTHEAST OH...EAST. DRY WEATHER EXPECTED THROUGH THE REST OF THE PERIOD AS A HIGH PRESSURE BUILDS IN. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... AN UPPER LEVEL SYSTEM COMBINED WITH A WARM FRONTAL BOUNDARY WILL ALLOW PRECIP TO OVERSPREAD MOST OF THE AREA THRU THE EVENING. THIS WILL MAINLY BE IN THE FORM OF RA...SAVE FOR A BRIEF PERIOD OF PL POSSIBLY ON THE FRONT END OF THE PRECIP THIS AFTERNOON. EXPECT VSBY TO LOWER INTO MVFR AS THE PRECIP MOVES ALONG WITH A GRADUAL LOWERING OF CIGS INTO MVFR HEADING INTO THIS EVENING. ONCE THIS UPPER LEVEL SYSTEM PASSES...EXPECT A SHRA REGIME TO TAKE HOLD WITH A WARM FRONTAL BOUNDARY LINGERING. AGAIN...RA EXPECTED TO BE DOMINATE PRECIP TYPE AT ALL TAF SITES. SOME FRZ RA OR PL MIXTURE IS EXPECTED IN THE N MOUNTAINS THIS EVENING. CIGS AND VSBY EXPECTED TO LOWER INTO IFR TONIGHT FOR MOST TAF SITES WITH EKN HOLDING OUT THE LONGEST. A SFC LOW WILL ORGANIZE OVER TN VALLEY...WITH ANOTHER WARM FRONT DEVELOPING INTO THE REGION FOR FRIDAY. THIS WILL INCREASE THE COVERAGE OF PRECIP ONCE AGAIN...WITH MOST OF THE RA N AND W OF A HTS/CRW/CKB LINE. CONDITIONS SHOULD IMPROVE FOR KCRW AND PERHAPS KBKW ONCE INTO THE WARM SECTOR WHILE IFR CONDITIONS IN RA PERSIST ELSEWHERE. SFC FLOW WILL BE LIGHT AND VARIABLE...MAINLY FROM THE E. LIGHT W FLOW ALOFT WILL BECOME LIGHT SW TONIGHT...INCREASING A BIT TOWARD DAWN FRI. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS IN RAIN MAY VARY OVERNIGHT TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H M M H H H HTS CONSISTENCY H H M M H H H H H H H H BKW CONSISTENCY H H H M M H H H H H M M EKN CONSISTENCY H H H H H H H H H M M H PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z FRIDAY... IFR POSSIBLE OVERNIGHT FRIDAY INTO THE WEEKEND IN RAIN...WITH FREEZING RAIN LIKELY IN THE NORTHERN MOUNTAINS...MAINLY E OF THE CHEAT RIDGE...INTO FRIDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY FROM 8 PM THIS EVENING TO 11 AM EST FRIDAY FOR WVZ046. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30/26 NEAR TERM...30 SHORT TERM...SL LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
200 PM EST THU DEC 4 2014 .SYNOPSIS... SERIES OF LOW PRESSURE WAVES CROSS INTO THE WEEKEND. HIGH PRESSURE SUNDAY. COLD FRONT EARLY NEXT WEEK MAY BE FOLLOWED A BY LONGER PERIOD OF HIGH PRESSURE. && .NEAR TERM /THROUGH FRIDAY/... PRECIP EXPANDING NE A BIT QUICKER THAN PREVIOUS FORECAST. STILL A SIGNIFICANT DRY LAYER IN THE LOWER LAYERS TO OVERCOME...BUT IT WONT TAKE LONG FOR THIS TO ERODE ONCE THE PRECIP MOVES IN. EXCEPTION BEING ACROSS SE OH AND N WV WHERE THE DRY LAYER IS A BIT MORE ROBUST. USED LATEST HRRR FOR TIMING OF HIGH POPS IN THRU THIS AFTERNOON AND EVENING. ALSO INSERTED A BRIEF PERIOD OF SLEET MIXING IN ON THE LEADING EDGE ACROSS NE KY/ W WV/ AND SE OH. THIS MIX CAN BE EXPECTED IN THE N MOUNTAINS AS WELL. ONCE THIS WAVE MOVES BY...CWA LEFT WITH WARM FRONT THIS EVENING WITH SHRA REGIME MAINLY N HALF OF CWA. WILL WATCH FOR A SURFACE LOW TO ORGANIZE OVER THE TN VALLEY WITH A WARM FRONT APPENDAGE DEVELOPING INTO AREA LATE TONIGHT. THIS WILL INCREASE THE COVERAGE OF PRECIP HEADING INTO FRIDAY AS THE WARM FRONT SLOWLY SHIFTS INTO SE OH. THERE MAY BE AN EXTENDED LULL IN PRECIP ACROSS SW VA AND SE WV FRIDAY WITH THESE AREAS IN WARM SECTOR. AFTER INTERROGATING HI RES MODELS AND SREF PROBS...ELECTED NOT TO EXPAND THE FRZ RA ADVISORY TO RANDOLPH. ASIDE FROM A BRIEF MIX LATER THIS AFTERNOON...EXPECT BULK OF PRECIP TONIGHT TO FALL AS RAIN. THERE COULD BE A LITTLE FRZ RA ACROSS FAR EASTERN RANDOLPH BUT DEFINITELY NOT A COUNTY WIDE AVG. IN FACT...THERE IS CONCERN THAT TEMPS MAY WARM ENOUGH TONIGHT FOR RAIN EVEN OVER POCAHONTAS COUNTY. HI RES NAM IS BY FAR COOLEST OF THE MODELS...KEEPING A SUB FRZ THIN LAYER AROUND H9. ELEVATIONS ABOVE 3 KFT SHOULD GET INTO WARM LAYER SUCH THAT RISING TEMPS ARE EXPECTED TONIGHT. IT SHOULD BE QUITE MILD TOMORROW IN WARM SECTOR WHERE MID TO UPPER 50S WERE CODED UP ACROSS SW VA UP TO I64. DOWNSLOPING COMPONENT PROBABLY ALSO SENDS EKN INTO THE LOW 50S. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IN THE SHORT TERM PERIOD. WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE AREA ON FRIDAY. WITH COLDER AIR EXPECTED TO BE AT THE SURFACE ALONG THE HIGHER TERRAIN...AND THE WARMER AIR MOVING IN ALOFT...THIS WILL SET UP A SCENARIO OF LIGHT FREEZING RAIN EARLY FRIDAY ACROSS NORTHERN MOUNTAINS. THIS WILL TAPER OFF BY LATE MORNING/EARLY AFTERNOON...AS LOW PRESSURE WAVE MOVES INTO THE REGION...AND WARMER AIR IS ABLE TO ERODE AWAY THE COLDER SURFACE TEMPERATURES...EVENTUALLY CHANGING ALL PRECIP TO RAIN. LOTS OF MOISTURE EXPECTED ACROSS THE AREA DURING THIS EVENT WITH A GOOD TAP OF GULF MOISTURE...WITH PW VALUES PROGGED TO RISE TO AROUND 1.1 TO 1.2 INCHES. EXPECTING A DECENT SHOT OF RAIN...PARTICULARLY ACROSS THE NORTH...WHERE LOW IS EXPECTED TO TRACK. AT THIS POINT...EXPECTING A GENERAL 1 TO 1.3 INCHES OF QPF. AT THIS POINT...ISSUES ON AREA WATERWAYS IS NOT EXPECTED...BUT THIS WILL NEED TO BE MONITORED AS THE EVENT APPROACHES. LOW WILL MOVE OFF TO THE EAST SATURDAY INTO SUNDAY...WITH GRADUALLY DRYING WEATHER FROM WEST TO EAST AS IT DOES SO. COULD BE SOME -DZ OR -FZDZ AT THE END OF THE EVENT AS WARMER AIR WORKS ITS WAY IN ALOFT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... GFS/ECMWF MODELS SHOW GOOD CONTINUITY WITH A SFC LOW PRESSURE SYSTEM MOVING ACROSS OUR AREA SATURDAY. TEMPERATURES SEEMS TO BE WARM ENOUGH FOR PCPN TO FALL IN THE FORM OF RAIN. SUBTLE DIFFERENCES ARE EVIDENT IN THE TRAJECTORY OF THE LOW...AS THE GFS TAKES IT NORTHEAST AND THE ECMWF TAKES IT TO OUR SOUTHEAST BY 00Z SUNDAY. EITHER WAY...PCPN SEEMS TO LINGER SATURDAY NIGHT. OPTED TO INCREASE POPS TO HIGH CHANCE MAINLY WESTERN SLOPES AND EASTERN MOUNTAINS SATURDAY NIGHT AS THIS SYSTEM EXITS THE AREA. WIND FLOW WILL TURN FROM THE NORTH BY 00Z SUNDAY...VEERING FROM THE NORTHEAST BY 12Z SUNDAY. THIS FLOW WILL BRING COOL AND DRY AIR MASS TO THE AREA SUNDAY AND SUNDAY NIGHT. DIFFERENCES AMONG MODEL SOLUTIONS ARE EVIDENT STARTING AT 12Z MONDAY...WHEN THE GFS BRINGS AN H500 HIGH AMPLITUDE WAVE ACROSS THE MS AND OH VALLEYS WHILE THE ECMWF BRINGS A BROAD AND STRONG CLOSED LOW DIGGING SOUTHEAST INTO OUR AREA MONDAY AND MONDAY NIGHT. CODED SLIGHT CHANCE TO CHANCE POPS WITH THIS FEATURE FOR NOW...AWAITING FOR BETTER CONSENSUS IN THE NEXT MODEL RUNS. AGAIN...MOST OF THE PCPN IS EXPECTED TO BE LIQUID...EXCEPT FOR THE DEEPER HOLLOWS NORTHEAST MOUNTAINS...WHERE THERE COULD BE A WINTRY MIX OR FREEZING RAIN. CAA EVIDENT IN H850 LEVEL WITH A MINUS 5C LINE CROSSING OUR NORTHERN SECTIONS AND EASTERN MOUNTAINS BY 18Z TUESDAY. THEREFORE...CODED UPSLOPE SNOW SHOWERS OVER NORTHEAST MOUNTAINS. THE REST OF THE AREA SHOULD REMAIN DRY. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... AN UPPER LEVEL SYSTEM COMBINED WITH A WARM FRONTAL BOUNDARY WILL ALLOW PRECIP TO OVERSPREAD MOST OF THE AREA THRU THE EVENING. THIS WILL MAINLY BE IN THE FORM OF RA...SAVE FOR A BRIEF PERIOD OF PL POSSIBLY ON THE FRONT END OF THE PRECIP THIS AFTERNOON. EXPECT VSBY TO LOWER INTO MVFR AS THE PRECIP MOVES ALONG WITH A GRADUAL LOWERING OF CIGS INTO MVFR HEADING INTO THIS EVENING. ONCE THIS UPPER LEVEL SYSTEM PASSES...EXPECT A SHRA REGIME TO TAKE HOLD WITH A WARM FRONTAL BOUNDARY LINGERING. AGAIN...RA EXPECTED TO BE DOMINATE PRECIP TYPE AT ALL TAF SITES. SOME FRZ RA OR PL MIXTURE IS EXPECTED IN THE N MOUNTAINS THIS EVENING. CIGS AND VSBY EXPECTED TO LOWER INTO IFR TONIGHT FOR MOST TAF SITES WITH EKN HOLDING OUT THE LONGEST. A SFC LOW WILL ORGANIZE OVER TN VALLEY...WITH ANOTHER WARM FRONT DEVELOPING INTO THE REGION FOR FRIDAY. THIS WILL INCREASE THE COVERAGE OF PRECIP ONCE AGAIN...WITH MOST OF THE RA N AND W OF A HTS/CRW/CKB LINE. CONDITIONS SHOULD IMPROVE FOR KCRW AND PERHAPS KBKW ONCE INTO THE WARM SECTOR WHILE IFR CONDITIONS IN RA PERSIST ELSEWHERE. SFC FLOW WILL BE LIGHT AND VARIABLE...MAINLY FROM THE E. LIGHT W FLOW ALOFT WILL BECOME LIGHT SW TONIGHT...INCREASING A BIT TOWARD DAWN FRI. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS IN RAIN MAY VARY OVERNIGHT TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H M M H H H HTS CONSISTENCY H H M M H H H H H H H H BKW CONSISTENCY H H H M M H H H H H M M EKN CONSISTENCY H H H H H H H H H M M H PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z FRIDAY... IFR POSSIBLE OVERNIGHT FRIDAY INTO THE WEEKEND IN RAIN...WITH FREEZING RAIN LIKELY IN THE NORTHERN MOUNTAINS...MAINLY E OF THE CHEAT RIDGE...INTO FRIDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY FROM 8 PM THIS EVENING TO 11 AM EST FRIDAY FOR WVZ046. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30/26 NEAR TERM...30 SHORT TERM...SL LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1021 AM EST THU DEC 4 2014 .SYNOPSIS... HIGH PRESSURE EXITS TODAY. SERIES OF LOW PRESSURE WAVES CROSS LATE TODAY INTO THE WEEKEND. HIGH PRESSURE SUNDAY. COLD FRONT EARLY NEXT WEEK MAY BE FOLLOWED A BY LONGER PERIOD OF HIGH PRESSURE. && .NEAR TERM /THROUGH TONIGHT/... 1000 AM UPDATE... PRECIP EXPANDING NE A BIT QUICKER THAN PREVIOUS FORECAST. STILL A SIGNIFICANT DRY LAYER IN THE LOWER LAYERS TO OVERCOME...BUT UPSTREAM OBS OVER KY REVEAL IT WONT TAKE LONG FOR THIS TO ERODE ONCE THE PRECIP MOVES IN. EXCEPTION BEING ACROSS SE OH AND N WV WHERE THE DRY LAYER IS A BIT MORE ROBUST. USED LATEST HRRR FOR TIMING OF HIGH POPS IN THRU THIS AFTERNOON. ALSO INSERTED A BRIEF PERIOD OF SLEET MIXING IN ON THE LEADING EDGE ACROSS NE KY/ W WV/ AND SE OH. PREV DISCN... HIGH PRESSURE OVER THE GREAT LAKES AND OHIO VALLEY THIS MORNING SCOOTS ENEWD TO THE NERN CONUS BY THIS EVENING. THIS QUICK MOVER IS ASSOCIATED WITH A LARGE AREA OF BONE DRY AIR FROM H85 TO H4. ITS QUICK EXODUS ALLOWS THE FIRST OF A SERIES OF WAVES OF LOW PRESSURE...EACH PRECEDED BY ISENTROPIC LIFT. ISENTROPIC LIFT ARRIVES/COMMENCES 15-18Z TODAY...BUT IT MAY TAKE A BIT LONGER TO SATURATE THE DRY MID LEVELS...ESPECIALLY N...AND THERE MAY BE A SHARP NRN CUTOFF AS A RESULT. ISENTROPIC SURFACES SHOW THAT WE SHOULD BE IN A WARM WEDGE BY FRI MORNING. BENEATH RIDGING ALOFT...THE PATTERN STARTS TO BECOME A BIT MUDDLED BY THEN BEFORE THE NEXT WAVE APPROACHES. HAVE RAIN ONLY SLOWLY WANING IN THE W. THE HIGH SLOWS DOWN A BIT...EASING OFF THE NEW ENGLAND COAST ON FRI. THIS DRIVES THE CAD LATE TONIGHT INTO FRI AS AGEOSTROPHIC WINDS INCREASE THERE TONIGHT AND PERSIST ON FRI...GIVING RISE TO ANOTHER FREEZING RAIN THREAT. THE START TIME WILL DEPEND UPON HOW SLOWLY DEW POINTS RISE TONIGHT AND THE WET BULB PROCESSES THE PRECIPITATION BEGINS THIS EVENING...OPTED FOR 8 PM WHEN POPS REACH LIKELY. HIGHS WERE LOWERED TODAY ON ACCOUNT OF THE FASTER TIMING OF THE SYSTEM AND ITS ASSOCIATED INCREASE IN CLOUD AND ONSET OF RAIN. BLENDED IN THE BIAS CORRECTED VERSIONS OF THE ECMWF AND THE MET. BLENDED IN THE NAM AND MET FOR NON DIURNAL TEMPERATURES TONIGHT WHICH DID NOT ENTAIL MUCH CHANGE AT ALL FROM THE PREVIOUS FCST. THIS IS ON THE LOWER SIDE GUIDANCE OVERALL AND CLOSER TO RAW BLENDS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IN THE SHORT TERM PERIOD. WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE AREA ON FRIDAY. WITH COLDER AIR EXPECTED TO BE AT THE SURFACE ALONG THE HIGHER TERRAIN...AND THE WARMER AIR MOVING IN ALOFT...THIS WILL SET UP A SCENARIO OF LIGHT FREEZING RAIN EARLY FRIDAY ACROSS NORTHERN MOUNTAINS. THIS WILL TAPER OFF BY LATE MORNING/EARLY AFTERNOON...AS LOW PRESSURE WAVE MOVES INTO THE REGION...AND WARMER AIR IS ABLE TO ERODE AWAY THE COLDER SURFACE TEMPERATURES...EVENTUALLY CHANGING ALL PRECIP TO RAIN. LOTS OF MOISTURE EXPECTED ACROSS THE AREA DURING THIS EVENT WITH A GOOD TAP OF GULF MOISTURE...WITH PW VALUES PROGGED TO RISE TO AROUND 1.1 TO 1.2 INCHES. EXPECTING A DECENT SHOT OF RAIN...PARTICULARLY ACROSS THE NORTH...WHERE LOW IS EXPECTED TO TRACK. AT THIS POINT...EXPECTING A GENERAL 1 TO 1.3 INCHES OF QPF. AT THIS POINT...ISSUES ON AREA WATERWAYS IS NOT EXPECTED...BUT THIS WILL NEED TO BE MONITORED AS THE EVENT APPROACHES. LOW WILL MOVE OFF TO THE EAST SATURDAY INTO SUNDAY...WITH GRADUALLY DRYING WEATHER FROM WEST TO EAST AS IT DOES SO. COULD BE SOME -DZ OR -FZDZ AT THE END OF THE EVENT AS WARMER AIR WORKS ITS WAY IN ALOFT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... GFS/ECMWF MODELS SHOW GOOD CONTINUITY WITH A SFC LOW PRESSURE SYSTEM MOVING ACROSS OUR AREA SATURDAY. TEMPERATURES SEEMS TO BE WARM ENOUGH FOR PCPN TO FALL IN THE FORM OF RAIN. SUBTLE DIFFERENCES ARE EVIDENT IN THE TRAJECTORY OF THE LOW...AS THE GFS TAKES IT NORTHEAST AND THE ECMWF TAKES IT TO OUR SOUTHEAST BY 00Z SUNDAY. EITHER WAY...PCPN SEEMS TO LINGER SATURDAY NIGHT. OPTED TO INCREASE POPS TO HIGH CHANCE MAINLY WESTERN SLOPES AND EASTERN MOUNTAINS SATURDAY NIGHT AS THIS SYSTEM EXITS THE AREA. WIND FLOW WILL TURN FROM THE NORTH BY 00Z SUNDAY...VEERING FROM THE NORTHEAST BY 12Z SUNDAY. THIS FLOW WILL BRING COOL AND DRY AIR MASS TO THE AREA SUNDAY AND SUNDAY NIGHT. DIFFERENCES AMONG MODEL SOLUTIONS ARE EVIDENT STARTING AT 12Z MONDAY...WHEN THE GFS BRINGS AN H500 HIGH AMPLITUDE WAVE ACROSS THE MS AND OH VALLEYS WHILE THE ECMWF BRINGS A BROAD AND STRONG CLOSED LOW DIGGING SOUTHEAST INTO OUR AREA MONDAY AND MONDAY NIGHT. CODED SLIGHT CHANCE TO CHANCE POPS WITH THIS FEATURE FOR NOW...AWAITING FOR BETTER CONSENSUS IN THE NEXT MODEL RUNS. AGAIN...MOST OF THE PCPN IS EXPECTED TO BE LIQUID...EXCEPT FOR THE DEEPER HOLLOWS NORTHEAST MOUNTAINS...WHERE THERE COULD BE A WINTRY MIX OR FREEZING RAIN. CAA EVIDENT IN H850 LEVEL WITH A MINUS 5C LINE CROSSING OUR NORTHERN SECTIONS AND EASTERN MOUNTAINS BY 18Z TUESDAY. THEREFORE...CODED UPSLOPE SNOW SHOWERS OVER NORTHEAST MOUNTAINS. THE REST OF THE AREA SHOULD REMAIN DRY. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... THE DAY DAWNS WITH HIGH IFR TO MVFR STRATOCU SE SITES...INCLUDING CRW...EKN AND BKW...AND MVFR MIST NW SITES WHERE IT HAD CLEARED OVERNIGHT...INCLUDING HTS...PKB AND CKB. BOTH SHOULD BE GONE BY 15Z ALTHOUGH MVFR MORNING MAY FORM FOR AN HOUR OR TWO WHERE IT CLEARED. A LOW PRESSURE SYSTEM APPROACHING FROM THE W WILL BRING LOWERING AND THICKENING CLOUDS TODAY. CIGS SHOULD LOWER TO MVFR BY 00Z FRI ACROSS SRN WV...ERN KY AND SW VA AND INCLUDING HTS AND BKW AND THEN CRW. MVFR CIGS SPREAD AREA WIDE BY 06Z FRI...AND LOWER TO IFR IN THE MOUNTAINS AND IN THE MIDDLE OHIO VALLEY 06-12Z FRI. VSBY WITH THE RAIN LATE TODAY AND TONIGHT WILL BE MAINLY MVFR AND MAINLY S AND E OF THE OHIO RIVER. IFR VSBY IN RAIN IS MOST LIKELY IN THE MOUNTAINS TONIGHT. FREEZING RAIN IS LIKELY OVERNIGHT TONIGHT IN THE MOUNTAINS E OF THE CHEAT RIDGE...INCLUDING THE GREENBRIER VALLEY. SFC FLOW WILL BE LIGHT AND VARIABLE...MAINLY FROM THE E. LIGHT W FLOW ALOFT WILL BECOME LIGHT SW TONIGHT...INCREASING A BIT TOWARD DAWN FRI. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OR ERADICATION OF MVFR VSBYS AND CIGS THIS MORNING MAY VARY...AS MAY ONSET OF MVFR RAIN LATER TODAY AND TONIGHT. TIMING AND EXTENT OF IFR CONDITIONS IN RAIN MAY VARY OVERNIGHT TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 CRW CONSISTENCY M H H H H H H H H H H M HTS CONSISTENCY H H M M H H M M M M M M BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z FRIDAY... IFR POSSIBLE OVERNIGHT FRIDAY INTO THE WEEKEND IN RAIN...WITH FREEZING RAIN LIKELY IN THE NORTHERN MOUNTAINS...MAINLY E OF THE CHEAT RIDGE...INTO FRIDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY FROM 8 PM THIS EVENING TO 11 AM EST FRIDAY FOR WVZ046. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/LS NEAR TERM...TRM/30 SHORT TERM...SL LONG TERM...ARJ AVIATION...TRM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
944 AM EST THU DEC 4 2014 .SYNOPSIS... AN AREA OF RAIN IS EXPECTED TO MOVE INTO THE REGION TODAY...AS A WARM FRONT GRADUALLY DEVELOPS NEAR THE OHIO RIVER. A MORE POTENT AREA OF LOW PRESSURE WILL MOVE ACROSS THE OHIO VALLEY ON FRIDAY AND INTO SATURDAY...WITH RAIN EXPECTED THROUGH SATURDAY AFTERNOON. AN AREA OF HIGH PRESSURE WILL ALLOW FOR DRIER AND COOLER CONDITIONS ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... PRECIPITATION HAS SPREAD INTO NORTHERN KENTUCKY AND WILL CONTINUE TO SLIDE EAST. MEASURABLE PRECIPITATION SHOULD MAKE IT A BIT FURTHER NORTH THAN WHAT IS CURRENTLY OCCURRING. BUT FOR THE MOST PART IT SHOULD REMAIN CONFINED TO AREAS ALONG AND SOUTH OF THE OHIO RIVER. HAVE NOT GOTTEN ANY REPORTS THUS FAR...BUT HRRR AND RAP SOUNDINGS CONTINUE TO SHOW THE POSSIBILITY OF SOME SLEET OR EVEN SNOW MIXING IN ALONG THE NORTHERN EDGE OF THE PRECIPITATION. BUT FOR THE MOST PART THIS WILL BE A RAIN EVENT WITH AMOUNTS LESS THAN 1/4 INCH. EXPECT PRECIPITATION TO START DIMINISHING THE WEST LATE IN THE DAY ALTHOUGH SOME LINGERING SPOTTY RAIN CANNOT BE COMPLETELY RULED OUT. PRECIPITATION AND EXTENSIVE CLOUD COVER SHOULD RESULT IN A VERY SLOW TEMPERATURE RISE. AND HAVE OPTED TO LOWER HIGHS A FEW DEGREES EVEN IN NORTHERN COUNTIES THAT WILL REMAIN DRY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ATTENTION FOR THE NEXT FEW DAYS WILL TURN TO THE RAIN EXPECTED ACROSS THE ENTIRE FORECAST AREA FROM FRIDAY THROUGH SATURDAY. A WELL-DEFINED AND MODERATELY STRONG 500MB SHORTWAVE WILL BE MOVING EAST ACROSS THE MISSISSIPPI VALLEY BY FRIDAY NIGHT...CLEARING THROUGH THE OHIO VALLEY BY SATURDAY EVENING. THE REFLECTION OF THIS TROUGH LOWER IN THE ATMOSPHERE IS ACTUALLY EVEN SHARPER...WITH A CLOSED LOW SHOWING UP AT THE SURFACE AND AT 925MB. THIS SYSTEM WILL HAVE A MUCH MORE IMPRESSIVE CONNECTION TO DEEP GULF MOISTURE THAN HAS BEEN IN PLACE FOR QUITE A WHILE. ALTHOUGH SOME LIGHT PRECIPITATION IS EXPECTED TO GRADUALLY SPREAD NORTH THROUGH THE FORECAST AREA TONIGHT AND INTO EARLY FRIDAY MORNING...THE MAJORITY OF THE RAIN IS EXPECTED TO MOVE INTO THE SOUTHWESTERN CWA BY 18Z FRIDAY. BY LATE FRIDAY...PRECIPITABLE WATER VALUES OF OVER AN INCH WILL ADVECT INTO THE ILN FORECAST AREA...WELL ABOVE CLIMATOLOGICAL NORMALS FOR DECEMBER. THE 00Z MODELS TONIGHT HAVE MADE A SLIGHT SHIFT NORTHWARD WITH THE TRACK OF THE SURFACE LOW...AND THUS THE AREA OF GREATEST PROLONGED LOW-LEVEL CONVERGENCE ALONG THE DEVELOPING FRONTAL STRUCTURE. TO NO SURPRISE...THE QPF AXIS DEPICTED ON THE VARIOUS MODEL SOLUTIONS HAS SHIFTED A LITTLE MORE SOLIDLY ACROSS THE ILN FORECAST AREA...AND RAINFALL AMOUNTS OF OVER AN INCH LOOK VERY LIKELY. A FEW SPOTS RECEIVING UP TO TWO INCHES MAY OCCUR. DESPITE THIS...THE FLOODING THREAT APPEARS RELATIVELY MINIMAL. BASED ON OHRFC MMEFS GUIDANCE...RIVERS (WHICH ARE RUNNING FAIRLY LOW AT THE MOMENT) DO NOT SHOW A HIGH PROBABILITY FOR FLOODING. A WIDESPREAD 1.0-1.5 INCH RAIN OVER ABOUT 24 HOURS IS ALSO PROBABLY NOT ENOUGH FOR GENERAL NON-RIVER FLOOD CONCERNS. THE AMERICAN MODELS (GFS/NAM) REMAIN ON THE FAST SIDE OF THE GUIDANCE ENVELOPE FOR THE EVENTUAL DEPARTURE OF PRECIPITATION ON SATURDAY. THE ECMWF/GEM MAINTAIN THE SLOWER END OF THE PROGRESSION...WITH DEEPER DEPICTIONS OF THE 500MB TROUGH. WITH A SIGNIFICANT TEMPERATURE GRADIENT EXPECTED TO DEVELOP OVER THE AREA...ADVECTION-BASED NON-DIURNAL TEMPERATURE TRENDS WERE USED IN THE GRIDS...CONFIDENCE IN EXACT NUMBERS IS NOT PARTICULARLY HIGH. PRECIPITATION DOES APPEAR LIKELY TO END BEFORE TEMPERATURES ARE COLD ENOUGH TO SUPPORT ANYTHING BUT RAIN...BUT WITH THE SURFACE FRONT BEGINNING ITS SOUTHWARD MOTION EARLY SATURDAY MORNING...FALLING TEMPERATURES ARE LIKELY ON SATURDAY. UNDER DRY CONDITIONS...TEMPERATURES WILL END UP WITHIN A FEW DEGREES EITHER SIDE OF THE FREEZING MARK ON SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... WHILE COLD ADVECTION WILL PERSIST ON SUNDAY...CLEARER SKIES WILL ALLOW FOR SOME TEMPERATURES TO REACH NEAR OR SLIGHTLY ABOVE CLIMO. RAIN SHOWERS MONDAY WILL MIX WITH SNOW OVERNIGHT BEFORE ENDING. THE HIGH WILL REMAIN WELL N OF THE OHIO VALLEY BUT THE AXIS SHOULD CROSS SUNDAY NIGHT AND SIGNIFY A SWITCH TO SOUTHERLY AND WARMING FLOW...IF ONLY SLIGHTLY WARMER. ANOTHER COLD FRONT WILL CROSS MONDAY NIGHT AND TUESDAY WILL BE CLOUDY AND COOL WITH READINGS IN THE 30S. HIGH PRESSURE WILL THEN POOL NW OF THE REGION FOR THE MIDDLE OF NEXT WEEK AND BRING MORE NORMAL TEMPERATURES WITH A DRY PATTERN. MODELS DIVERGE SIGNIFICANTLY MONDAY NIGHT AND FCST IS IN A HIGHER STATE OF UNCERTAINTY BEYOND THIS TIME. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... SEVERAL TAF SITES WILL EXPERIENCE MAINLY MVFR VISIBILITIES THIS MORNING. FOR LATER TODAY...AN UPPER LEVEL DISTURBANCE ALONG WITH AN INCREASING LOW LEVEL JET WILL RESULT IN RAIN DEVELOPMENT TO OUR SOUTHWEST. THIS RAIN SHIELD WILL EVENTUALLY PUSH NORTHEAST TOWARD THE OHIO RIVER BY 18Z. KCVG AND KLUK HAVE THE BEST CHANCE TO SEE RAIN WHERE FORCING WILL BE THE GREATEST. THE RAIN THREAT WILL DECREASE APPRECIABLY NORTH OF KILN TAF SITE. CEILINGS SHOULD REMAIN VFR WITH PERHAPS A REDUCTION TO MVFR VISIBILITIES AT KCVG/KLUK. IT SHOULD BE NOTED THAT THERE MAY BE A BRIEF PERIOD OF LIGHT SLEET AT THE ONSET OF THE PCPN DUE TO THE INITIALLY DRY LOW LEVELS AND A LITTLE BIT OF WARM AIR ALOFT TO ALLOW PARTIAL MELTING OF LIGHT PRECIPITATION. THIS THREAT APPEARS LOW ENOUGH TO NOT MENTION IN THE TAFS ATTM. FOR TONIGHT...UPPER LEVEL DISTURBANCE MOVES EAST AND THE LOW LEVEL JET BRIEFLY WEAKENS EARLY ON. DURING THE LATER PART OF THE NIGHT INTO FRIDAY MORNING...A WARM...MOIST PUSH IS FORECAST TO OCCUR AND MOVE NORTHEAST THROUGH THE REGION OVERNIGHT. THE LOW LEVELS WILL CONTINUE TO SATURATE...RESULTING IN CEILINGS DROPPING INTO THE IFR CATEGORY WITH VISIBILITIES AT LEAST DROPPING INTO THE MVFR CATEGORY. THE WEAK ASCENT AND SATURATED LOW LEVELS WILL BRING A THREAT FOR EITHER DRIZZLE OR LIGHT RAIN...ESPECIALLY BETWEEN 06Z AND 12Z. OUTLOOK...IFR/LIFR CEILINGS AND VISIBILITIES LIKELY FRIDAY INTO FRIDAY NIGHT. MVFR/IFR CEILINGS AND MVFR VISIBILITIES EXPECTED TO LINGER INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...FRANKS AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
606 AM EST THU DEC 4 2014 .SYNOPSIS... AN AREA OF RAIN IS EXPECTED TO MOVE INTO THE REGION TODAY...AS A WARM FRONT GRADUALLY DEVELOPS NEAR THE OHIO RIVER. A MORE POTENT AREA OF LOW PRESSURE WILL MOVE ACROSS THE OHIO VALLEY ON FRIDAY AND INTO SATURDAY...WITH RAIN EXPECTED THROUGH SATURDAY AFTERNOON. AN AREA OF HIGH PRESSURE WILL ALLOW FOR DRIER AND COOLER CONDITIONS ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOLID CANOPY OF HIGH CLOUDS HAS OVERSPREAD THE AREA...AND MID-LEVEL CLOUDS ARE NOW BEING OBSERVED IN FAR SOUTHERN INDIANA AND WESTERN KENTUCKY. DESPITE THESE CLOUDS...A FEW PATCHES OF FOG HAVE DEVELOPED...WITH JUST ENOUGH LOW-LEVEL MOISTURE TO LEAD TO SOME HEAVY FROST. THE FOG HAS NOT BEEN PARTICULARLY DENSE (ONLY A COUPLE OBSERVATION SITES BRIEFLY DROPPED TO 1/4 MILE)...BUT THERE IS A CONCERN THAT WHERE FOG IS A LITTLE THICKER...SOME OF IT MAY DEPOSIT ICE ON SURFACES. THIS WILL BE MONITORED HEADING INTO THE NEXT FEW HOURS. NEAR-SURFACE CONDITIONS ARE EXPECTED TO REMAIN FAIRLY COOL TODAY...WITH EASTERLY FLOW FROM 925MB AND BELOW. HOWEVER...AT 850MB...A WARM FRONT IS ALREADY BEGINNING TO SET UP. THIS FRONT WILL MOVE NORTH INTO THE ILN FORECAST AREA AFTER 12Z. THE FRONT IS ALSO EXPECTED TO ACT AS A FOCUS FOR PRECIPITATION...WHICH WILL BE AIDED BY THE PASSAGE OF A WEAK SHORTWAVE IN THE GENERALLY ZONAL 500MB FLOW. THE MAJORITY OF THIS PRECIPITATION SHOULD REMAIN SOUTH OF THE OHIO RIVER...BUT LIGHT ACTIVITY IS EXPECTED TO BE POSSIBLE THROUGH AT LEAST THE SOUTHERN HALF OF THE FORECAST AREA BY LATE MORNING / EARLY AFTERNOON. THERE REMAINS SOME SLIGHT CONCERN REGARDING PRECIPITATION TYPE...AS SURFACE TEMPERATURES WILL BE STARTING OFF IN THE LOWER 30S AND UPPER 20S...AND THE LAYER OF WARM AIR ALOFT IS NOT QUITE BEING TIMED OUT WITH EXACT CONSISTENCY FROM MODEL TO MODEL. IT DOES APPEAR LIKELY THAT SURFACE TEMPS WILL BE RISING ABOVE FREEZING BEFORE PRECIPITATION BEGINS...THOUGH IF THERE IS ANY CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...IT COULD OCCUR IN SOUTHEAST INDIANA IN THE 12Z-15Z TIME PERIOD. IT APPEARS THAT THE MORE LIKELY SCENARIO WILL BE FOR PRECIPITATION BEGINNING JUST AS THE 925MB-800MB IS IN THE PROCESS OF WARMING ABOVE FREEZING. WITH SOME SATURATION NEAR THE SURFACE STILL NEEDING TO OCCUR...THIS TEMPERATURE PROFILE WOULD SUPPORT A BRIEF MIX OF SLEET AND RAIN...BEFORE THE ENTIRE SOUNDING BELOW 800MB ENDS UP ABOVE FREEZING. THIS COULD OCCUR AT TWO DIFFERENT TIMES IN THE FORECAST. THE FIRST OCCURRENCE WOULD BE AS THE INITIAL AREA OF PRECIPITATION MOVES INTO THE SOUTHWESTERN QUADRANT OF THE FORECAST AREA THIS MORNING. HRRR AND 4KM WRF OUTPUT DOES SUGGEST THAT THERE WILL BE VIRGA IN ADVANCE OF SURFACE PRECIPITATION (WITH SIMULATED COMP REFLECTIVITY SHOWING A GREATER AREAL EXPANSE THAN SIMULATED 1KM REFLECTIVITY). AS IS SOMETIMES OBSERVED IN THESE SITUATIONS...THE FIRST HYDROMETEORS TO HIT THE GROUND MAY BE PELLETS. THE SECOND POSSIBLE OCCURRENCE OF SLEET WOULD BE AS LIGHT PRECIPITATION EXPANDS NORTHWARD THIS EVENING...AFFECTING THE NORTHERN HALF OF THE FORECAST AREA. REGARDLESS...WITH SLEET ONLY LIKELY TO OCCUR FOR A BRIEF PERIOD OF TIME NEAR THE ONSET OF PRECIPITATION...MEASURABLE ACCUMULATIONS ARE UNLIKELY. POPS FOR TODAY FOCUS ON THE SOUTHERN THIRD OF THE FORECAST AREA...WHERE RAIN NOW APPEARS TO BE A CERTAINTY. SURFACE TEMPERATURES ARE EXPECTED TO REACH THE UPPER 30S TO LOWER 40S...BUT THERE IS SOME CHANCE THAT PRECIPITATION COULD HOLD THESE VALUES DOWN A FEW DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ATTENTION FOR THE NEXT FEW DAYS WILL TURN TO THE RAIN EXPECTED ACROSS THE ENTIRE FORECAST AREA FROM FRIDAY THROUGH SATURDAY. A WELL-DEFINED AND MODERATELY STRONG 500MB SHORTWAVE WILL BE MOVING EAST ACROSS THE MISSISSIPPI VALLEY BY FRIDAY NIGHT...CLEARING THROUGH THE OHIO VALLEY BY SATURDAY EVENING. THE REFLECTION OF THIS TROUGH LOWER IN THE ATMOSPHERE IS ACTUALLY EVEN SHARPER...WITH A CLOSED LOW SHOWING UP AT THE SURFACE AND AT 925MB. THIS SYSTEM WILL HAVE A MUCH MORE IMPRESSIVE CONNECTION TO DEEP GULF MOISTURE THAN HAS BEEN IN PLACE FOR QUITE A WHILE. ALTHOUGH SOME LIGHT PRECIPITATION IS EXPECTED TO GRADUALLY SPREAD NORTH THROUGH THE FORECAST AREA TONIGHT AND INTO EARLY FRIDAY MORNING...THE MAJORITY OF THE RAIN IS EXPECTED TO MOVE INTO THE SOUTHWESTERN CWA BY 18Z FRIDAY. BY LATE FRIDAY...PRECIPITABLE WATER VALUES OF OVER AN INCH WILL ADVECT INTO THE ILN FORECAST AREA...WELL ABOVE CLIMATOLOGICAL NORMALS FOR DECEMBER. THE 00Z MODELS TONIGHT HAVE MADE A SLIGHT SHIFT NORTHWARD WITH THE TRACK OF THE SURFACE LOW...AND THUS THE AREA OF GREATEST PROLONGED LOW-LEVEL CONVERGENCE ALONG THE DEVELOPING FRONTAL STRUCTURE. TO NO SURPRISE...THE QPF AXIS DEPICTED ON THE VARIOUS MODEL SOLUTIONS HAS SHIFTED A LITTLE MORE SOLIDLY ACROSS THE ILN FORECAST AREA...AND RAINFALL AMOUNTS OF OVER AN INCH LOOK VERY LIKELY. A FEW SPOTS RECEIVING UP TO TWO INCHES MAY OCCUR. DESPITE THIS...THE FLOODING THREAT APPEARS RELATIVELY MINIMAL. BASED ON OHRFC MMEFS GUIDANCE...RIVERS (WHICH ARE RUNNING FAIRLY LOW AT THE MOMENT) DO NOT SHOW A HIGH PROBABILITY FOR FLOODING. A WIDESPREAD 1.0-1.5 INCH RAIN OVER ABOUT 24 HOURS IS ALSO PROBABLY NOT ENOUGH FOR GENERAL NON-RIVER FLOOD CONCERNS. THE AMERICAN MODELS (GFS/NAM) REMAIN ON THE FAST SIDE OF THE GUIDANCE ENVELOPE FOR THE EVENTUAL DEPARTURE OF PRECIPITATION ON SATURDAY. THE ECMWF/GEM MAINTAIN THE SLOWER END OF THE PROGRESSION...WITH DEEPER DEPICTIONS OF THE 500MB TROUGH. WITH A SIGNIFICANT TEMPERATURE GRADIENT EXPECTED TO DEVELOP OVER THE AREA...ADVECTION-BASED NON-DIURNAL TEMPERATURE TRENDS WERE USED IN THE GRIDS...CONFIDENCE IN EXACT NUMBERS IS NOT PARTICULARLY HIGH. PRECIPITATION DOES APPEAR LIKELY TO END BEFORE TEMPERATURES ARE COLD ENOUGH TO SUPPORT ANYTHING BUT RAIN...BUT WITH THE SURFACE FRONT BEGINNING ITS SOUTHWARD MOTION EARLY SATURDAY MORNING...FALLING TEMPERATURES ARE LIKELY ON SATURDAY. UNDER DRY CONDITIONS...TEMPERATURES WILL END UP WITHIN A FEW DEGREES EITHER SIDE OF THE FREEZING MARK ON SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... WHILE COLD ADVECTION WILL PERSIST ON SUNDAY...CLEARER SKIES WILL ALLOW FOR SOME TEMPERATURES TO REACH NEAR OR SLIGHTLY ABOVE CLIMO. RAIN SHOWERS MONDAY WILL MIX WITH SNOW OVERNIGHT BEFORE ENDING. THE HIGH WILL REMAIN WELL N OF THE OHIO VALLEY BUT THE AXIS SHOULD CROSS SUNDAY NIGHT AND SIGNIFY A SWITCH TO SOUTHERLY AND WARMING FLOW...IF ONLY SLIGHTLY WARMER. ANOTHER COLD FRONT WILL CROSS MONDAY NIGHT AND TUESDAY WILL BE CLOUDY AND COOL WITH READINGS IN THE 30S. HIGH PRESSURE WILL THEN POOL NW OF THE REGION FOR THE MIDDLE OF NEXT WEEK AND BRING MORE NORMAL TEMPERATURES WITH A DRY PATTERN. MODELS DIVERGE SIGNIFICANTLY MONDAY NIGHT AND FCST IS IN A HIGHER STATE OF UNCERTAINTY BEYOND THIS TIME. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... SEVERAL TAF SITES WILL EXPERIENCE MAINLY MVFR VISIBILITIES FOR ABOUT A COUPLE OF HOURS THIS MORNING. THICKENING CLOUDS AND WINDS PICKING UP SLIGHTLY FROM THE EAST FROM DEPARTING HIGH PRESSURE SHOULD HELP IMPROVE THE VISIBILITIES BY 14Z. FOR LATER TODAY...AN UPPER LEVEL DISTURBANCE ALONG WITH AN INCREASING LOW LEVEL JET WILL RESULT IN RAIN DEVELOPMENT TO OUR SOUTHWEST. THIS RAIN SHIELD WILL EVENTUALLY PUSH NORTHEAST TOWARD THE OHIO RIVER BY 18Z. KCVG AND KLUK HAVE THE BEST CHANCE TO SEE RAIN WHERE FORCING WILL BE THE GREATEST. THE RAIN THREAT WILL DECREASE APPRECIABLY NORTH OF KILN TAF SITE. CEILINGS SHOULD REMAIN VFR WITH PERHAPS A REDUCTION TO MVFR VISIBILITIES AT KCVG/KLUK. IT SHOULD BE NOTED THAT THERE MAY BE A BRIEF PERIOD OF LIGHT SLEET AT THE ONSET OF THE PCPN DUE TO THE INITIALLY DRY LOW LEVELS AND A LITTLE BIT OF WARM AIR ALOFT TO ALLOW PARTIAL MELTING OF LIGHT PRECIPITATION. THIS THREAT APPEARS LOW ENOUGH TO NOT MENTION IN THE TAFS ATTM. FOR TONIGHT...UPPER LEVEL DISTURBANCE MOVES EAST AND THE LOW LEVEL JET BRIEFLY WEAKENS EARLY ON. DURING THE LATER PART OF THE NIGHT INTO FRIDAY MORNING...A WARM...MOIST PUSH IS FORECAST TO OCCUR AND MOVE NORTHEAST THROUGH THE REGION OVERNIGHT. THE LOW LEVELS WILL CONTINUE TO SATURATE...RESULTING IN CEILINGS DROPPING INTO THE IFR CATEGORY WITH VISIBILITIES AT LEAST DROPPING INTO THE MVFR CATEGORY. THE WEAK ASCENT AND SATURATED LOW LEVELS WILL BRING A THREAT FOR EITHER DRIZZLE OR LIGHT RAIN...ESPECIALLY BETWEEN 06Z AND 12Z. OUTLOOK...IFR/LIFR CEILINGS AND VISIBILITIES LIKELY FRIDAY INTO FRIDAY NIGHT. MVFR/IFR CEILINGS AND MVFR VISIBILITIES EXPECTED TO LINGER INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...FRANKS AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
601 AM EST THU DEC 4 2014 .SYNOPSIS... AN AREA OF RAIN IS EXPECTED TO MOVE INTO THE REGION TODAY...AS A WARM FRONT GRADUALLY DEVELOPS NEAR THE OHIO RIVER. A MORE POTENT AREA OF LOW PRESSURE WILL MOVE ACROSS THE OHIO VALLEY ON FRIDAY AND INTO SATURDAY...WITH RAIN EXPECTED THROUGH SATURDAY AFTERNOON. AN AREA OF HIGH PRESSURE WILL ALLOW FOR DRIER AND COOLER CONDITIONS ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOLID CANOPY OF HIGH CLOUDS HAS OVERSPREAD THE AREA...AND MID-LEVEL CLOUDS ARE NOW BEING OBSERVED IN FAR SOUTHERN INDIANA AND WESTERN KENTUCKY. DESPITE THESE CLOUDS...A FEW PATCHES OF FOG HAVE DEVELOPED...WITH JUST ENOUGH LOW-LEVEL MOISTURE TO LEAD TO SOME HEAVY FROST. THE FOG HAS NOT BEEN PARTICULARLY DENSE (ONLY A COUPLE OBSERVATION SITES BRIEFLY DROPPED TO 1/4 MILE)...BUT THERE IS A CONCERN THAT WHERE FOG IS A LITTLE THICKER...SOME OF IT MAY DEPOSIT ICE ON SURFACES. THIS WILL BE MONITORED HEADING INTO THE NEXT FEW HOURS. NEAR-SURFACE CONDITIONS ARE EXPECTED TO REMAIN FAIRLY COOL TODAY...WITH EASTERLY FLOW FROM 925MB AND BELOW. HOWEVER...AT 850MB...A WARM FRONT IS ALREADY BEGINNING TO SET UP. THIS FRONT WILL MOVE NORTH INTO THE ILN FORECAST AREA AFTER 12Z. THE FRONT IS ALSO EXPECTED TO ACT AS A FOCUS FOR PRECIPITATION...WHICH WILL BE AIDED BY THE PASSAGE OF A WEAK SHORTWAVE IN THE GENERALLY ZONAL 500MB FLOW. THE MAJORITY OF THIS PRECIPITATION SHOULD REMAIN SOUTH OF THE OHIO RIVER...BUT LIGHT ACTIVITY IS EXPECTED TO BE POSSIBLE THROUGH AT LEAST THE SOUTHERN HALF OF THE FORECAST AREA BY LATE MORNING / EARLY AFTERNOON. THERE REMAINS SOME SLIGHT CONCERN REGARDING PRECIPITATION TYPE...AS SURFACE TEMPERATURES WILL BE STARTING OFF IN THE LOWER 30S AND UPPER 20S...AND THE LAYER OF WARM AIR ALOFT IS NOT QUITE BEING TIMED OUT WITH EXACT CONSISTENCY FROM MODEL TO MODEL. IT DOES APPEAR LIKELY THAT SURFACE TEMPS WILL BE RISING ABOVE FREEZING BEFORE PRECIPITATION BEGINS...THOUGH IF THERE IS ANY CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...IT COULD OCCUR IN SOUTHEAST INDIANA IN THE 12Z-15Z TIME PERIOD. IT APPEARS THAT THE MORE LIKELY SCENARIO WILL BE FOR PRECIPITATION BEGINNING JUST AS THE 925MB-800MB IS IN THE PROCESS OF WARMING ABOVE FREEZING. WITH SOME SATURATION NEAR THE SURFACE STILL NEEDING TO OCCUR...THIS TEMPERATURE PROFILE WOULD SUPPORT A BRIEF MIX OF SLEET AND RAIN...BEFORE THE ENTIRE SOUNDING BELOW 800MB ENDS UP ABOVE FREEZING. THIS COULD OCCUR AT TWO DIFFERENT TIMES IN THE FORECAST. THE FIRST OCCURRENCE WOULD BE AS THE INITIAL AREA OF PRECIPITATION MOVES INTO THE SOUTHWESTERN QUADRANT OF THE FORECAST AREA THIS MORNING. HRRR AND 4KM WRF OUTPUT DOES SUGGEST THAT THERE WILL BE VIRGA IN ADVANCE OF SURFACE PRECIPITATION (WITH SIMULATED COMP REFLECTIVITY SHOWING A GREATER AREAL EXPANSE THAN SIMULATED 1KM REFLECTIVITY). AS IS SOMETIMES OBSERVED IN THESE SITUATIONS...THE FIRST HYDROMETEORS TO HIT THE GROUND MAY BE PELLETS. THE SECOND POSSIBLE OCCURRENCE OF SLEET WOULD BE AS LIGHT PRECIPITATION EXPANDS NORTHWARD THIS EVENING...AFFECTING THE NORTHERN HALF OF THE FORECAST AREA. REGARDLESS...WITH SLEET ONLY LIKELY TO OCCUR FOR A BRIEF PERIOD OF TIME NEAR THE ONSET OF PRECIPITATION...MEASURABLE ACCUMULATIONS ARE UNLIKELY. POPS FOR TODAY FOCUS ON THE SOUTHERN THIRD OF THE FORECAST AREA...WHERE RAIN NOW APPEARS TO BE A CERTAINTY. SURFACE TEMPERATURES ARE EXPECTED TO REACH THE UPPER 30S TO LOWER 40S...BUT THERE IS SOME CHANCE THAT PRECIPITATION COULD HOLD THESE VALUES DOWN A FEW DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ATTENTION FOR THE NEXT FEW DAYS WILL TURN TO THE RAIN EXPECTED ACROSS THE ENTIRE FORECAST AREA FROM FRIDAY THROUGH SATURDAY. A WELL-DEFINED AND MODERATELY STRONG 500MB SHORTWAVE WILL BE MOVING EAST ACROSS THE MISSISSIPPI VALLEY BY FRIDAY NIGHT...CLEARING THROUGH THE OHIO VALLEY BY SATURDAY EVENING. THE REFLECTION OF THIS TROUGH LOWER IN THE ATMOSPHERE IS ACTUALLY EVEN SHARPER...WITH A CLOSED LOW SHOWING UP AT THE SURFACE AND AT 925MB. THIS SYSTEM WILL HAVE A MUCH MORE IMPRESSIVE CONNECTION TO DEEP GULF MOISTURE THAN HAS BEEN IN PLACE FOR QUITE A WHILE. ALTHOUGH SOME LIGHT PRECIPITATION IS EXPECTED TO GRADUALLY SPREAD NORTH THROUGH THE FORECAST AREA TONIGHT AND INTO EARLY FRIDAY MORNING...THE MAJORITY OF THE RAIN IS EXPECTED TO MOVE INTO THE SOUTHWESTERN CWA BY 18Z FRIDAY. BY LATE FRIDAY...PRECIPITABLE WATER VALUES OF OVER AN INCH WILL ADVECT INTO THE ILN FORECAST AREA...WELL ABOVE CLIMATOLOGICAL NORMALS FOR DECEMBER. THE 00Z MODELS TONIGHT HAVE MADE A SLIGHT SHIFT NORTHWARD WITH THE TRACK OF THE SURFACE LOW...AND THUS THE AREA OF GREATEST PROLONGED LOW-LEVEL CONVERGENCE ALONG THE DEVELOPING FRONTAL STRUCTURE. TO NO SURPRISE...THE QPF AXIS DEPICTED ON THE VARIOUS MODEL SOLUTIONS HAS SHIFTED A LITTLE MORE SOLIDLY ACROSS THE ILN FORECAST AREA...AND RAINFALL AMOUNTS OF OVER AN INCH LOOK VERY LIKELY. A FEW SPOTS RECEIVING UP TO TWO INCHES MAY OCCUR. DESPITE THIS...THE FLOODING THREAT APPEARS RELATIVELY MINIMAL. BASED ON OHRFC MMEFS GUIDANCE...RIVERS (WHICH ARE RUNNING FAIRLY LOW AT THE MOMENT) DO NOT SHOW A HIGH PROBABILITY FOR FLOODING. A WIDESPREAD 1.0-1.5 INCH RAIN OVER ABOUT 24 HOURS IS ALSO PROBABLY NOT ENOUGH FOR GENERAL NON-RIVER FLOOD CONCERNS. THE AMERICAN MODELS (GFS/NAM) REMAIN ON THE FAST SIDE OF THE GUIDANCE ENVELOPE FOR THE EVENTUAL DEPARTURE OF PRECIPITATION ON SATURDAY. THE ECMWF/GEM MAINTAIN THE SLOWER END OF THE PROGRESSION...WITH DEEPER DEPICTIONS OF THE 500MB TROUGH. WITH A SIGNIFICANT TEMPERATURE GRADIENT EXPECTED TO DEVELOP OVER THE AREA...ADVECTION-BASED NON-DIURNAL TEMPERATURE TRENDS WERE USED IN THE GRIDS...CONFIDENCE IN EXACT NUMBERS IS NOT PARTICULARLY HIGH. PRECIPITATION DOES APPEAR LIKELY TO END BEFORE TEMPERATURES ARE COLD ENOUGH TO SUPPORT ANYTHING BUT RAIN...BUT WITH THE SURFACE FRONT BEGINNING ITS SOUTHWARD MOTION EARLY SATURDAY MORNING...FALLING TEMPERATURES ARE LIKELY ON SATURDAY. UNDER DRY CONDITIONS...TEMPERATURES WILL END UP WITHIN A FEW DEGREES EITHER SIDE OF THE FREEZING MARK ON SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... WHILE COLD ADVECTION WILL PERSIST ON SUNDAY...CLEARER SKIES WILL ALLOW FOR SOME TEMPERATURES TO REACH NEAR OR SLIGHTLY ABOVE CLIMO. RAIN SHOWERS MONDAY WILL MIX WITH SNOW OVERNIGHT BEFORE ENDING. THE HIGH WILL REMAIN WELL N OF THE OHIO VALLEY BUT THE AXIS SHOULD CROSS SUNDAY NIGHT AND SIGNIFY A SWITCH TO SOUTHERLY AND WARMING FLOW...IF ONLY SLIGHTLY WARMER. ANOTHER COLD FRONT WILL CROSS MONDAY NIGHT AND TUESDAY WILL BE CLOUDY AND COOL WITH READINGS IN THE 30S. HIGH PRESSURE WILL THEN POOL NW OF THE REGION FOR THE MIDDLE OF NEXT WEEK AND BRING MORE NORMAL TEMPERATURES WITH A DRY PATTERN. MODELS DIVERGE SIGNIFICANTLY MONDAY NIGHT AND FCST IS IN A HIGHER STATE OF UNCERTAINTY BEYOND THIS TIME. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... SEVERAL TAF SITES WILL EXPERIENCE MAINLY MVFR VISIBILITIES FOR ABOUT A COUPLE OF HOURS THIS MORNING. THICKENING CLOUDS AND WINDS PICKING UP SLIGHTLY FROM THE EAST FROM DEPARTING HIGH PRESSURE SHOULD HELP IMPROVE THE VISIBILITIES BY 14Z. FOR LATER TODAY...AN UPPER LEVEL DISTURBANCE ALONG WITH AN INCREASING LOW LEVEL JET WILL RESULT IN RAIN DEVELOPMENT TO OUR SOUTHWEST. THIS RAIN SHIELD WILL EVENTUALLY PUSH NORTHEAST TOWARD THE OHIO RIVER BY 18Z. KCVG AND KLUK HAVE THE BEST CHANCE TO SEE RAIN WHERE FORCING WILL BE THE GREATEST. THE THREAT WILL DECREASE APPRECIABLY NORTH OF KILN TAF SITE. CEILINGS SHOULD REMAIN VFR WITH PERHAPS A REDUCTION TO MVFR VISIBILITIES AT KCVG/KLUK. FOR TONIGHT...UPPER LEVEL DISTURBANCE MOVES EAST AND THE LOW LEVEL JET BRIEFLY WEAKENS EARLY ON. DURING THE LATER PART OF THE NIGHT INTO FRIDAY MORNING...A WARM...MOIST PUSH IS FORECAST TO OCCUR AND MOVE NORTHEAST THROUGH THE REGION OVERNIGHT. THE LOW LEVELS WILL CONTINUE TO SATURATE...RESULTING IN CEILINGS DROPPING INTO THE IFR CATEGORY WITH VISIBILITIES AT LEAST DROPPING INTO THE MVFR CATEGORY. THE WEAK ASCENT AND SATURATED LOW LEVELS WILL BRING A THREAT FOR EITHER DRIZZLE OR LIGHT RAIN...ESPECIALLY BETWEEN 06Z AND 12Z. OUTLOOK...IFR/LIFR CEILINGS AND VISIBILITIES LIKELY FRIDAY INTO FRIDAY NIGHT. MVFR/IFR CEILINGS AND MVFR VISIBILITIES EXPECTED TO LINGER INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...FRANKS AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
421 AM EST THU DEC 4 2014 .SYNOPSIS... AN AREA OF RAIN IS EXPECTED TO MOVE INTO THE REGION TODAY...AS A WARM FRONT GRADUALLY DEVELOPS NEAR THE OHIO RIVER. A MORE POTENT AREA OF LOW PRESSURE WILL MOVE ACROSS THE OHIO VALLEY ON FRIDAY AND INTO SATURDAY...WITH RAIN EXPECTED THROUGH SATURDAY AFTERNOON. AN AREA OF HIGH PRESSURE WILL ALLOW FOR DRIER AND COOLER CONDITIONS ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOLID CANOPY OF HIGH CLOUDS HAS OVERSPREAD THE AREA...AND MID-LEVEL CLOUDS ARE NOW BEING OBSERVED IN FAR SOUTHERN INDIANA AND WESTERN KENTUCKY. DESPITE THESE CLOUDS...A FEW PATCHES OF FOG HAVE DEVELOPED...WITH JUST ENOUGH LOW-LEVEL MOISTURE TO LEAD TO SOME HEAVY FROST. THE FOG HAS NOT BEEN PARTICULARLY DENSE (ONLY A COUPLE OBSERVATION SITES BRIEFLY DROPPED TO 1/4 MILE)...BUT THERE IS A CONCERN THAT WHERE FOG IS A LITTLE THICKER...SOME OF IT MAY DEPOSIT ICE ON SURFACES. THIS WILL BE MONITORED HEADING INTO THE NEXT FEW HOURS. NEAR-SURFACE CONDITIONS ARE EXPECTED TO REMAIN FAIRLY COOL TODAY...WITH EASTERLY FLOW FROM 925MB AND BELOW. HOWEVER...AT 850MB...A WARM FRONT IS ALREADY BEGINNING TO SET UP. THIS FRONT WILL MOVE NORTH INTO THE ILN FORECAST AREA AFTER 12Z. THE FRONT IS ALSO EXPECTED TO ACT AS A FOCUS FOR PRECIPITATION...WHICH WILL BE AIDED BY THE PASSAGE OF A WEAK SHORTWAVE IN THE GENERALLY ZONAL 500MB FLOW. THE MAJORITY OF THIS PRECIPITATION SHOULD REMAIN SOUTH OF THE OHIO RIVER...BUT LIGHT ACTIVITY IS EXPECTED TO BE POSSIBLE THROUGH AT LEAST THE SOUTHERN HALF OF THE FORECAST AREA BY LATE MORNING / EARLY AFTERNOON. THERE REMAINS SOME SLIGHT CONCERN REGARDING PRECIPITATION TYPE...AS SURFACE TEMPERATURES WILL BE STARTING OFF IN THE LOWER 30S AND UPPER 20S...AND THE LAYER OF WARM AIR ALOFT IS NOT QUITE BEING TIMED OUT WITH EXACT CONSISTENCY FROM MODEL TO MODEL. IT DOES APPEAR LIKELY THAT SURFACE TEMPS WILL BE RISING ABOVE FREEZING BEFORE PRECIPITATION BEGINS...THOUGH IF THERE IS ANY CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...IT COULD OCCUR IN SOUTHEAST INDIANA IN THE 12Z-15Z TIME PERIOD. IT APPEARS THAT THE MORE LIKELY SCENARIO WILL BE FOR PRECIPITATION BEGINNING JUST AS THE 925MB-800MB IS IN THE PROCESS OF WARMING ABOVE FREEZING. WITH SOME SATURATION NEAR THE SURFACE STILL NEEDING TO OCCUR...THIS TEMPERATURE PROFILE WOULD SUPPORT A BRIEF MIX OF SLEET AND RAIN...BEFORE THE ENTIRE SOUNDING BELOW 800MB ENDS UP ABOVE FREEZING. THIS COULD OCCUR AT TWO DIFFERENT TIMES IN THE FORECAST. THE FIRST OCCURRENCE WOULD BE AS THE INITIAL AREA OF PRECIPITATION MOVES INTO THE SOUTHWESTERN QUADRANT OF THE FORECAST AREA THIS MORNING. HRRR AND 4KM WRF OUTPUT DOES SUGGEST THAT THERE WILL BE VIRGA IN ADVANCE OF SURFACE PRECIPITATION (WITH SIMULATED COMP REFLECTIVITY SHOWING A GREATER AREAL EXPANSE THAN SIMULATED 1KM REFLECTIVITY). AS IS SOMETIMES OBSERVED IN THESE SITUATIONS...THE FIRST HYDROMETEORS TO HIT THE GROUND MAY BE PELLETS. THE SECOND POSSIBLE OCCURRENCE OF SLEET WOULD BE AS LIGHT PRECIPITATION EXPANDS NORTHWARD THIS EVENING...AFFECTING THE NORTHERN HALF OF THE FORECAST AREA. REGARDLESS...WITH SLEET ONLY LIKELY TO OCCUR FOR A BRIEF PERIOD OF TIME NEAR THE ONSET OF PRECIPITATION...MEASURABLE ACCUMULATIONS ARE UNLIKELY. POPS FOR TODAY FOCUS ON THE SOUTHERN THIRD OF THE FORECAST AREA...WHERE RAIN NOW APPEARS TO BE A CERTAINTY. SURFACE TEMPERATURES ARE EXPECTED TO REACH THE UPPER 30S TO LOWER 40S...BUT THERE IS SOME CHANCE THAT PRECIPITATION COULD HOLD THESE VALUES DOWN A FEW DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ATTENTION FOR THE NEXT FEW DAYS WILL TURN TO THE RAIN EXPECTED ACROSS THE ENTIRE FORECAST AREA FROM FRIDAY THROUGH SATURDAY. A WELL-DEFINED AND MODERATELY STRONG 500MB SHORTWAVE WILL BE MOVING EAST ACROSS THE MISSISSIPPI VALLEY BY FRIDAY NIGHT...CLEARING THROUGH THE OHIO VALLEY BY SATURDAY EVENING. THE REFLECTION OF THIS TROUGH LOWER IN THE ATMOSPHERE IS ACTUALLY EVEN SHARPER...WITH A CLOSED LOW SHOWING UP AT THE SURFACE AND AT 925MB. THIS SYSTEM WILL HAVE A MUCH MORE IMPRESSIVE CONNECTION TO DEEP GULF MOISTURE THAN HAS BEEN IN PLACE FOR QUITE A WHILE. ALTHOUGH SOME LIGHT PRECIPITATION IS EXPECTED TO GRADUALLY SPREAD NORTH THROUGH THE FORECAST AREA TONIGHT AND INTO EARLY FRIDAY MORNING...THE MAJORITY OF THE RAIN IS EXPECTED TO MOVE INTO THE SOUTHWESTERN CWA BY 18Z FRIDAY. BY LATE FRIDAY...PRECIPITABLE WATER VALUES OF OVER AN INCH WILL ADVECT INTO THE ILN FORECAST AREA...WELL ABOVE CLIMATOLOGICAL NORMALS FOR DECEMBER. THE 00Z MODELS TONIGHT HAVE MADE A SLIGHT SHIFT NORTHWARD WITH THE TRACK OF THE SURFACE LOW...AND THUS THE AREA OF GREATEST PROLONGED LOW-LEVEL CONVERGENCE ALONG THE DEVELOPING FRONTAL STRUCTURE. TO NO SURPRISE...THE QPF AXIS DEPICTED ON THE VARIOUS MODEL SOLUTIONS HAS SHIFTED A LITTLE MORE SOLIDLY ACROSS THE ILN FORECAST AREA...AND RAINFALL AMOUNTS OF OVER AN INCH LOOK VERY LIKELY. A FEW SPOTS RECEIVING UP TO TWO INCHES MAY OCCUR. DESPITE THIS...THE FLOODING THREAT APPEARS RELATIVELY MINIMAL. BASED ON OHRFC MMEFS GUIDANCE...RIVERS (WHICH ARE RUNNING FAIRLY LOW AT THE MOMENT) DO NOT SHOW A HIGH PROBABILITY FOR FLOODING. A WIDESPREAD 1.0-1.5 INCH RAIN OVER ABOUT 24 HOURS IS ALSO PROBABLY NOT ENOUGH FOR GENERAL NON-RIVER FLOOD CONCERNS. THE AMERICAN MODELS (GFS/NAM) REMAIN ON THE FAST SIDE OF THE GUIDANCE ENVELOPE FOR THE EVENTUAL DEPARTURE OF PRECIPITATION ON SATURDAY. THE ECMWF/GEM MAINTAIN THE SLOWER END OF THE PROGRESSION...WITH DEEPER DEPICTIONS OF THE 500MB TROUGH. WITH A SIGNIFICANT TEMPERATURE GRADIENT EXPECTED TO DEVELOP OVER THE AREA...ADVECTION-BASED NON-DIURNAL TEMPERATURE TRENDS WERE USED IN THE GRIDS...CONFIDENCE IN EXACT NUMBERS IS NOT PARTICULARLY HIGH. PRECIPITATION DOES APPEAR LIKELY TO END BEFORE TEMPERATURES ARE COLD ENOUGH TO SUPPORT ANYTHING BUT RAIN...BUT WITH THE SURFACE FRONT BEGINNING ITS SOUTHWARD MOTION EARLY SATURDAY MORNING...FALLING TEMPERATURES ARE LIKELY ON SATURDAY. UNDER DRY CONDITIONS...TEMPERATURES WILL END UP WITHIN A FEW DEGREES EITHER SIDE OF THE FREEZING MARK ON SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... WHILE COLD ADVECTION WILL PERSIST ON SUNDAY...CLEARER SKIES WILL ALLOW FOR SOME TEMPERATURES TO REACH NEAR OR SLIGHTLY ABOVE CLIMO. RAIN SHOWERS MONDAY WILL MIX WITH SNOW OVERNIGHT BEFORE ENDING. THE HIGH WILL REMAIN WELL N OF THE OHIO VALLEY BUT THE AXIS SHOULD CROSS SUNDAY NIGHT AND SIGNIFY A SWITCH TO SOUTHERLY AND WARMING FLOW...IF ONLY SLIGHTLY WARMER. ANOTHER COLD FRONT WILL CROSS MONDAY NIGHT AND TUESDAY WILL BE CLOUDY AND COOL WITH READINGS IN THE 30S. HIGH PRESSURE WILL THEN POOL NW OF THE REGION FOR THE MIDDLE OF NEXT WEEK AND BRING MORE NORMAL TEMPERATURES WITH A DRY PATTERN. MODELS DIVERGE SIGNIFICANTLY MONDAY NIGHT AND FCST IS IN A HIGHER STATE OF UNCERTAINTY BEYOND THIS TIME. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE FORECAST AREA THROUGH 12Z. ALTHOUGH HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN OVERNIGHT...SOME MIST/FOG HAS ALREADY FORMED AT SOME OF THE MORE FOG PRONE TAF SITES SUCH AS KILN AND KLUK. KLUK HAS BASICALLY DROPPED DOWN 1/4SM IN FZFG WITH CEILINGS RANGING BETWEEN 300 AND 500 FEET. SINCE THE FOG HAS FORMED...AND WITH NO MIXING AT THE SURFACE OVERNIGHT...IT IS UNCLEAR HOW MUCH THE FOG WILL IMPROVE AT KLUK AS CLOUDS CONTINUE TO THICKEN. THIS PROCESS MAY EVENTUALLY ALLOW VISIBILITIES/CEILINGS TO IMPROVE SOME (DUE TO SLIGHT WARMING). HAVE DECIDED TO KEEP CONDITIONS BELOW AIRPORT MINIMUM AT KLUK UNTIL 13Z UNTIL THERE SEEMS TO BE TREND ESTABLISHED. THEREAFTER...DAYTIME HEATING AND SOME MIXING/WIND AS THE CENTER OF THE SURFACE HIGH PULLS OFF TO THE NORTHEAST SHOULD ALLOW CONDITIONS TO RETURN TO VFR. ATTM...AM ONLY EXPECTING SOME MVFR VISIBILITIES IN MIST AT KCVG AND KILN UNTIL 13Z. FOR LATER TODAY...AN UPPER LEVEL DISTURBANCE ALONG WITH AN INCREASING LOW LEVEL JET WILL RESULT IN RAIN DEVELOPMENT TO OUR SOUTHWEST. THIS RAIN SHIELD WILL EVENTUALLY PUSH NORTHEAST TOWARD THE OHIO RIVER BY 18Z. BEST CHANCE TO SEE RAIN WILL BE AT KCVG AND KLUK WITH PERHAPS A LOWER THREAT OF LIGHT RAIN FARTHER NORTH AS THE MAIN FOCUS REMAINS ALONG AND SOUTH OF THE OHIO RIVER. CEILINGS SHOULD REMAIN VFR WITH PERHAPS A BRIEF REDUCTION TO MVFR VISIBILITIES AT KCVG/KLUK DUE TO THE LIGHT RAIN. FOR TONIGHT...UPPER LEVEL DISTURBANCE MOVES EAST AND THE LOW LEVEL JET BRIEFLY WEAKENS EARLY ON. DURING THE LATER PART OF THE NIGHT INTO FRIDAY MORNING...A WARM...MOIST PUSH IS FORECAST TO OCCUR AND MOVE NORTHEAST THROUGH THE REGION OVERNIGHT. THE LOW LEVELS WILL CONTINUE TO SATURATE...RESULTING IN CEILINGS DROPPING INTO THE IFR CATEGORY WITH VISIBILITIES AT LEAST DROPPING INTO THE MVFR CATEGORY. THE WEAK ASCENT AND SATURATED LOW LEVELS WILL BRING A THREAT FOR EITHER DRIZZLE OR LIGHT RAIN...ESPECIALLY BETWEEN 06Z AND 12Z. OUTLOOK...IFR/LIFR CEILINGS VISIBILITIES LIKELY FRIDAY INTO FRIDAY NIGHT. MVFR/IFR CEILINGS AND MVFR VISIBILITIES EXPECTED TO LINGER INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...FRANKS AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NORMAN OK
957 PM CST FRI DEC 5 2014 .AVIATION... DENSE FOG IS EXPECTED OVERNIGHT AND UNTIL LATE SATURDAY MORNING IN A ZONE FROM NORTH CENTRAL INTO CENTRAL OKLAHOMA. MUCH OF THIS WILL BE WEST OF OKLAHOMA CITY, BUT THE OKLAHOMA CITY MAY RECEIVE PERIODS OF DENSE FOG ALSO. THE LOW CLOUDS AND FOG WILL BE SLOW TO ERRODE SATURDAY, ALTHOUGH VISIBILITY WILL INCREASE BY LATE MORNING. LIGHT NORTH WINDS WILL PERSIST. && .PREV DISCUSSION... /ISSUED 842 PM CST FRI DEC 5 2014/ UPDATE... HAVE UPDATED GRIDS TO BE MORE AGGRESSIVE WITH FOG DEVELOPMENT. THE HRRR AND RAP MODELS ARE IN GOOD AGREEMENT WITH DENSE FOG DEVELOPING AND SPREADING ACROSS MUCH OF NORTH CENTRAL AND CENTRAL OKLAHOMA THIS EVENING AND OVERNIGHT. VISIBILITIES HAVE FALLEN TO 1/2SM OR LESS IN THE PAST HOUR OR SO AT PONCA CITY... VANCE AFB... ENID WOODRING... BLACKWELL... ARKANSAS CITY KS AND TEMPORARILY AT WATONGA AND GAGE. WILL LIKELY NEED A DENSE FOG ADVISORY LATER THIS EVENING IF THE VISIBILITIES CONTINUE TO WORSEN AND PERSIST. PREV DISCUSSION... /ISSUED 602 PM CST FRI DEC 5 2014/ AVIATION... IFR CEILINGS FROM SOUTHWEST TO NORTH CENTRAL OKLAHOMA ARE EXPECTED TO EXPAND LATER TONIGHT. THE SHALLOW COOL AIRMASS IS EXPECTED TO HOLD ON THROUGH MUCH OF SATURDAY ALONG WITH THE LOW CEILINGS. FOG IS EXPECTED LATE TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 42 51 39 54 / 10 10 0 20 HOBART OK 40 50 38 52 / 0 0 10 20 WICHITA FALLS TX 43 55 40 54 / 0 0 10 20 GAGE OK 32 48 34 57 / 0 0 0 10 PONCA CITY OK 39 48 35 52 / 10 10 10 20 DURANT OK 46 58 42 53 / 10 0 0 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 26/09/09
AREA FORECAST DISCUSSION
NWS NORMAN OK
842 PM CST FRI DEC 5 2014 .UPDATE... HAVE UPDATED GRIDS TO BE MORE AGGRESSIVE WITH FOG DEVELOPMENT. THE HRRR AND RAP MODELS ARE IN GOOD AGREEMENT WITH DENSE FOG DEVELOPING AND SPREADING ACROSS MUCH OF NORTH CENTRAL AND CENTRAL OKLAHOMA THIS EVENING AND OVERNIGHT. VISIBILITIES HAVE FALLEN TO 1/2SM OR LESS IN THE PAST HOUR OR SO AT PONCA CITY... VANCE AFB... ENID WOODRING... BLACKWELL... ARKANSAS CITY KS AND TEMPORARILY AT WATONGA AND GAGE. WILL LIKELY NEED A DENSE FOG ADVISORY LATER THIS EVENING IF THE VISIBILITIES CONTINUE TO WORSEN AND PERSIST. && .PREV DISCUSSION... /ISSUED 602 PM CST FRI DEC 5 2014/ AVIATION... IFR CEILINGS FROM SOUTHWEST TO NORTH CENTRAL OKLAHOMA ARE EXPECTED TO EXPAND LATER TONIGHT. THE SHALLOW COOL AIRMASS IS EXPECTED TO HOLD ON THROUGH MUCH OF SATURDAY ALONG WITH THE LOW CEILINGS. FOG IS EXPECTED LATE TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 42 51 39 54 / 10 10 0 20 HOBART OK 40 50 38 52 / 0 0 10 20 WICHITA FALLS TX 43 55 40 54 / 0 0 10 20 GAGE OK 32 48 34 57 / 0 0 0 10 PONCA CITY OK 39 48 35 52 / 10 10 10 20 DURANT OK 46 58 42 53 / 10 0 0 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
735 PM MST FRI DEC 5 2014 .UPDATE... ISSUED AT 725 PM MST FRI DEC 5 2014 STALLED LL BAROCLINIC ZONE ACROSS THE FAR NORTH WILL INTERACT WITH A PASSING MID LEVEL IMPULSE THIS EVENING...POSSIBLY SUPPORTING A FEW LIGHT SHOWERS ACROSS FAR NW SD. HAVE ADDED A SLIGHT CHANCE FOR PRECIP THERE...OPTING FOR A WINTRY MIX GIVEN WARM WEDGE ALOFT. OTHERWISE...SUFFICIENT LL MOISTURE AT THE SFC MAY SUPPORT PATCHY AREAS OF FOG LATER TONIGHT ACROSS WESTERN SD. HOWEVER...ENSUING SFC PRESSURE FALLS PER LEE SIDE TROUGHING WILL SUPPORTING INCREASING LL FLOW...INCREASING TURBULENT MIX DOWN OF DRY AIR. THIS WILL LIKELY LIMIT COVERAGE OF ANY FOG...ESP AWAY FROM VALLEYS. HAVE TRIMMED DOWN FOG MENTION AND RELEGATED MENTION TO PATCHY. && .SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT ISSUED AT 207 PM MST FRI DEC 5 2014 UPPER LEVEL ANALYSIS SHOWS A RIDGE OVER THE WESTERN CONUS...WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS. CANADIAN SURFACE HIGH IS MOVING SOUTHWARD INTO MT/ND. SKIES ARE PARTLY CLOUDY...WITH GENERALLY LIGHT WINDS AND TEMPS IN THE UPPER 30S AND 40S. LIGHT WINDS WILL BECOME SOUTHEASTERLY TONIGHT AS THE SURFACE HIGH CROSSES ND...BRINGING MOISTURE INTO THE AREA. SEVERAL MODELS ARE STILL HINTING AT SOME FOG SETTING UP AROUND THE AREA. THE HRRR AND RAP ARE SHOWING LOW CEILINGS ACROSS THE SD PLAINS DEVELOPING AFTER MIDNIGHT...AND LATEST RUNS ALSO HAVE FOG WRAPPING AROUND THE SOUTHERN HILLS INTO NORTHEAST WY. MEANWHILE THE NAM HAS THE BEST CHANCES FOR FOG AROUND THE HILLS AND INTO NORTHEAST WY...NOT SO MUCH ON THE SD PLAINS. THE NAM SEEMS TO BE OVERESTIMATING MOISTURE LATELY...AND SINCE WINDS IN NORTHEAST WY LOOK A LITTLE STRONGER OVERNIGHT...HAVE MORE UNCERTAINTY ABOUT FOG DEVELOPMENT THERE. DECREASED AREAS OF FOG TO PATCHY ACROSS NORTHEAST WY...KEEPING AREAS OF FOG JUST EAST OF THE HILLS. COULD ALSO BE SOME PATCHY FOG IN SURROUNDING AREAS ACROSS THE SD PLAINS. AS THE SURFACE HIGH MOVES SOUTHEAST OVERNIGHT...COLD AIR WILL ADVECT INTO THE EASTERN CWA. LOWS WILL RANGE FROM THE TEENS ACROSS NORTH CENTRAL/NORTHWEST SD TO THE UPPER 20S IN NORTHEAST WY. SOUTHERLY WINDS WILL BECOME BREEZY BY LATE SATURDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE HIGH PRESSURE TO THE EAST AND THE INCOMING LOW. EXPECT FOG TO DISSIPATE BY MID-MORNING. THERE IS SOME UNCERTAINTY WITH TEMPS ON SATURDAY...AS MODELS HAVE A 10-DEGREE SPREAD FOR HIGHS IN SOME PLACES. WITH SOUTHERLY BOUNDARY-LAYER WINDS AND WARM AIR ADVECTION...KEPT TEMPS MILD...IN THE MID 30S NORTH AND EAST TO THE UPPER 40S FARTHER WEST. LOWS SATURDAY NIGHT WILL BE IN THE 20S TO LOWER 30S. .LONG TERM...SUNDAY THROUGH FRIDAY ISSUED AT 207 PM MST FRI DEC 5 2014 MODELS ARE IN GOOD AGREEMENT DURING THE EXTENDED PERIOD...WITH RELATIVELY HIGH PREDICTABILITY THROUGH AT LEAST WEDNESDAY. IN THE MEAN...THERE WILL BE A LONG-WAVE TROUGH OFF THE WEST COAST WITH A LONG-WAVE RIDGE NEAR THE CNTRL CONUS. ON SUNDAY A SHORT-WAVE TROUGH WILL MOVE ACROSS THE FAR NRN PLAINS AND THROUGH THE L/W RIDGE...BRINGING A COLD FRONT AND NORTHWEST WIND SHIFT ACROSS THE CWA. THIS WILL BRING SCT SHRASN TO THE BLKHLS. ON MONDAY THROUGH WEDNESDAY THE RIDGE REBOUNDS...BUT WITH A WEAK SHORT- WAVE TROUGH SLOWLY MOVING ACROSS THE NRN PLAINS. THIS IS NOT EXPECTED TO BRING ANY PRECIP TO THE CWA GIVEN THE LIMITED FORCING FOR ASCENT AND LACK OF LOW- TO MID-LEVEL MOISTURE. ON THURSDAY AND FRIDAY...THE LONG-WAVE TROUGH MOVES INTO THE ERN HALF OF THE CONUS WITH SOUTHWEST FLOW ALOFT DEVELOPING ACROSS THE CWA IN RESPONSE TO A DEEP UPPER LOW COMING ONSHORE NEAR CA. THE GFS SEEMS A BIT AGGRESSIVE WITH THIS LOW...SO HAVE KEPT THE FORECAST DRY THROUGH FRIDAY. NEVERTHELESS...THERE ARE INDICATIONS THAT A BIG STORM COULD BE LOOMING ON THE HORIZON FOR LATE NEXT WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 427 PM MST FRI DEC 5 2014 VFR CONDITIONS EXPECTED THROUGH THE PERIOD MOST PLACES. INCREASED BL MOISTURE WITH A PERIOD OF LIGHT WINDS AND CLEAR SKIES MAY SUPPORT PATCHY/AREAS OF FOG TONIGHT. HOWEVER...INCREASING LL SOUTHERLY FLOW AND LIMITED MOISTURE ADVECTION SHOULD LIMIT COVERAGE OF ANY FOG/STRATUS. GIVEN LOW PROBS/CONFIDENCE HAVE OPTED TO LEAVE OUT OF TERMINALS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...JC SHORT TERM...POJORLIE LONG TERM...BUNKERS AVIATION...JC
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
658 PM CST FRI DEC 5 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 304 PM CST FRI DEC 5 2014 ALTHOUGH VISIBILITY HAS IMPROVED...FOG CONTINUES TO RESIDE THROUGH NORTHWEST IOWA THIS AFTERNOON...SO THE BIGGEST CHALLENGE TONIGHT REMAINS HOW QUICKLY FOG ERODES AS DRIER AIR FILTERS IN BEHIND THE SURFACE TROUGH PUSHING ACROSS THE REGION. WATCHING THE TRENDS THROUGH THE AFTERNOON...VISIBILITIES HAVE QUICKLY IMPROVED AS THE WINDS TRANSITIONED TO NORTHERLY BEHIND THE TROUGH AND THE DRIER AIR DRAINED IN. USING THAT AND RAP 925 MB RH FIELDS WHICH HAVE ALSO CORRELATED WELL WITH THE FOG...HAVE THE FOG LINGERING THROUGH PORTIONS OF NORTHWEST IOWA THROUGH THE EVENING THEN SLOWLY ERODING FROM THE NORTH AND WEST AS DRIER AIR TAKES OVER DURING THE NIGHT. COLDER AIR WILL ALSO FILTER SOUTH OVERNIGHT...WITH LOWS BOTTOMING OUT AROUND 10 THROUGH THE HIGHWAY 14 CORRIDOR TO THE UPPER TEENS THROUGH THE MISSOURI RIVER VALLEY. SURFACE HIGH PRESSURE SETTLES INTO THE REGION ON SATURDAY...SO SHOULD SEE SOME SUN ALONG WITH RELATIVELY LIGHT WINDS DURING THE DAY WITH A WEAK GRADIENT EXISTING ACROSS THE REGION. WITH THERMAL PROFILES A LITTLE COOLER HIGHS WILL RANGE FROM THE LOWER 30S NORTH TO UPPER 30S SOUTH. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 304 PM CST FRI DEC 5 2014 THE PRIMARY FORECAST CONCERNS IN THE MEDIUM AND SHORT RANGE CONTINUE TO FOCUS ON LIGHT PRECIPITATION CHANCES SUNDAY AND WARMUP INTO NEXT WEEK/WEEKEND. SUNDAY...MODELS STILL ON TRACK BRINGING TWO PIECES OF SHORTWAVE ENERGY INTO THE REGION LATE SATURDAY NIGHT AND INTO SUNDAY. THE FIRST WAVE WILL LIFT NORTHWARD FROM THE SOUTHWESTERN US WITH THE SECOND WAVE DIPPING SOUTHEAST FROM THE PACIFIC NORTHWEST. AGAIN...MOISTURE REMAINS RATHER SHALLOW IN NATURE AS THESE WAVES MOVE THROUGH BUT AM ANTICIPATING A NARROW CORRIDOR OF LIGHT FREEZING RAIN/DRIZZLE DEVELOPING NEAR DAYBREAK ALONG AND WEST OF I-29. WHILE THE ATMOSPHERIC PROFILE LACKS ICE CRYSTALS FOR MOST OF THE EVENT...THERE COULD BE A BRIEF WINDOW OF SATURATION EARLY IN THE AFTERNOON WHICH WOULD OWE TO SLEET INTRODUCTION ESPECIALLY IN THE NE ZONES. THE PRECIPITATION SHOULD BE LIGHT ENOUGH TO AVOID ANY MAJOR ICING CONCERNS...ESPECIALLY SINCE SFC TEMPERATURES WILL CONTINUE TO RISE THROUGH THE MORNING AND SHOULD CLIMB ABOVE FREEZING IN THE AFTERNOON. NEXT WEEK...SLIGHT MODEL DIFFERENCES CONTINUE FOR MUCH OF NEXT WEEK WITH BOTH MAJOR EXTENDED RANGE MODELS SHOWING INCREASED RIDGING ACROSS THE CONUS INTO NEXT WEEKEND. TEMPERATURES WILL COOL SLIGHTLY BEHIND SUNDAYS DEPARTING TROUGH...BUT STILL AVERAGE NEAR OR SLIGHTLY ABOVE SEASONAL NORMALS. FAIRLY SUBSTANTIAL DIFFERENCES PERSIST IN THE HANDLING OF SHORTWAVE ENERGY MOVING THROUGH THE PACIFIC NORTHWEST ON MONDAY. ECMWF KEEPS THIS ENERGY WELL NORTH OF THE CWA...MEANWHILE THE GFS PULLS THE WAVE THROUGH THE CENTRAL PLAINS. THE END RESULTS COULD BE SUBSTANTIAL DIFFERENT FOR WEDNESDAY- FRIDAY. SHOULD THE GFS SOLUTION VERIFY...THE RESULT WOULD BE INCREASED CLOUD COVER...FOG...AND SLIGHTLY COOLER TEMPS IN THE LOCAL AREA. ON THE FLIPSIDE...THE MORE AMPLIFIED ECMWF SOLN COULD SUGGEST VERY WARM TEMPERATURES THURSDAY AND INTO THE WEEKEND. FOR TODAY...PREFERENCES CONTINUE TO FALL TOWARDS THE ECMWF...BUT WILL HEDGE A BIT TOWARDS THE OTHER CAMP OF SOLNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 654 PM CST FRI DEC 5 2014 SOME PESKY IFR CEILINGS/MVFR VISIBILITIES ARE EXPECTED TO LINGER AROUND KSUX THROUGH AT LEAST 02Z...AND MVFR VISIBILITIES AT LEAST THROUGH 08Z...AS LOW LEVEL NORTHERLY FLOW CONTINUES TO ADVECT THE LINGERING LOW CLOUDS SOUTHWARD THIS EVENING. WILL HAVE TO WATCH FOR REFORMING OF LOWER CLOUDS AND FOG AROUND SIOUX CITY WITH HIGHER MOISTURE CONTENT OF THE LOWER LEVEL AIR MASS WILL BE LESS LIKELY TO FULLY FLUSH OUT AS FLOW WEAKENS TOWARD RIDGE AXIS LATER IN THE NIGHT...AND ACTUALLY TURNS EAST/SOUTHEAST AT LOW LEVELS DURING THE MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...DUX AVIATION...CHAPMAN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
436 PM MST FRI DEC 5 2014 .SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT ISSUED AT 207 PM MST FRI DEC 5 2014 UPPER LEVEL ANALYSIS SHOWS A RIDGE OVER THE WESTERN CONUS...WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS. CANADIAN SURFACE HIGH IS MOVING SOUTHWARD INTO MT/ND. SKIES ARE PARTLY CLOUDY...WITH GENERALLY LIGHT WINDS AND TEMPS IN THE UPPER 30S AND 40S. LIGHT WINDS WILL BECOME SOUTHEASTERLY TONIGHT AS THE SURFACE HIGH CROSSES ND...BRINGING MOISTURE INTO THE AREA. SEVERAL MODELS ARE STILL HINTING AT SOME FOG SETTING UP AROUND THE AREA. THE HRRR AND RAP ARE SHOWING LOW CEILINGS ACROSS THE SD PLAINS DEVELOPING AFTER MIDNIGHT...AND LATEST RUNS ALSO HAVE FOG WRAPPING AROUND THE SOUTHERN HILLS INTO NORTHEAST WY. MEANWHILE THE NAM HAS THE BEST CHANCES FOR FOG AROUND THE HILLS AND INTO NORTHEAST WY...NOT SO MUCH ON THE SD PLAINS. THE NAM SEEMS TO BE OVERESTIMATING MOISTURE LATELY...AND SINCE WINDS IN NORTHEAST WY LOOK A LITTLE STRONGER OVERNIGHT...HAVE MORE UNCERTAINTY ABOUT FOG DEVELOPMENT THERE. DECREASED AREAS OF FOG TO PATCHY ACROSS NORTHEAST WY...KEEPING AREAS OF FOG JUST EAST OF THE HILLS. COULD ALSO BE SOME PATCHY FOG IN SURROUNDING AREAS ACROSS THE SD PLAINS. AS THE SURFACE HIGH MOVES SOUTHEAST OVERNIGHT...COLD AIR WILL ADVECT INTO THE EASTERN CWA. LOWS WILL RANGE FROM THE TEENS ACROSS NORTH CENTRAL/NORTHWEST SD TO THE UPPER 20S IN NORTHEAST WY. SOUTHERLY WINDS WILL BECOME BREEZY BY LATE SATURDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE HIGH PRESSURE TO THE EAST AND THE INCOMING LOW. EXPECT FOG TO DISSIPATE BY MID-MORNING. THERE IS SOME UNCERTAINTY WITH TEMPS ON SATURDAY...AS MODELS HAVE A 10-DEGREE SPREAD FOR HIGHS IN SOME PLACES. WITH SOUTHERLY BOUNDARY-LAYER WINDS AND WARM AIR ADVECTION...KEPT TEMPS MILD...IN THE MID 30S NORTH AND EAST TO THE UPPER 40S FARTHER WEST. LOWS SATURDAY NIGHT WILL BE IN THE 20S TO LOWER 30S. .LONG TERM...SUNDAY THROUGH FRIDAY ISSUED AT 207 PM MST FRI DEC 5 2014 MODELS ARE IN GOOD AGREEMENT DURING THE EXTENDED PERIOD...WITH RELATIVELY HIGH PREDICTABILITY THROUGH AT LEAST WEDNESDAY. IN THE MEAN...THERE WILL BE A LONG-WAVE TROUGH OFF THE WEST COAST WITH A LONG-WAVE RIDGE NEAR THE CNTRL CONUS. ON SUNDAY A SHORT-WAVE TROUGH WILL MOVE ACROSS THE FAR NRN PLAINS AND THROUGH THE L/W RIDGE...BRINGING A COLD FRONT AND NORTHWEST WIND SHIFT ACROSS THE CWA. THIS WILL BRING SCT SHRASN TO THE BLKHLS. ON MONDAY THROUGH WEDNESDAY THE RIDGE REBOUNDS...BUT WITH A WEAK SHORT- WAVE TROUGH SLOWLY MOVING ACROSS THE NRN PLAINS. THIS IS NOT EXPECTED TO BRING ANY PRECIP TO THE CWA GIVEN THE LIMITED FORCING FOR ASCENT AND LACK OF LOW- TO MID-LEVEL MOISTURE. ON THURSDAY AND FRIDAY...THE LONG-WAVE TROUGH MOVES INTO THE ERN HALF OF THE CONUS WITH SOUTHWEST FLOW ALOFT DEVELOPING ACROSS THE CWA IN RESPONSE TO A DEEP UPPER LOW COMING ONSHORE NEAR CA. THE GFS SEEMS A BIT AGGRESSIVE WITH THIS LOW...SO HAVE KEPT THE FORECAST DRY THROUGH FRIDAY. NEVERTHELESS...THERE ARE INDICATIONS THAT A BIG STORM COULD BE LOOMING ON THE HORIZON FOR LATE NEXT WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 427 PM MST FRI DEC 5 2014 VFR CONDITIONS EXPECTED THROUGH THE PERIOD MOST PLACES. INCREASED BL MOISTURE WITH A PERIOD OF LIGHT WINDS AND CLEAR SKIES MAY SUPPORT PATCHY/AREAS OF FOG TONIGHT. HOWEVER...INCREASING LL SOUTHERLY FLOW AND LIMITED MOISTURE ADVECTION SHOULD LIMIT COVERAGE OF ANY FOG/STRATUS. GIVEN LOW PROBS/CONFIDENCE HAVE OPTED TO LEAVE OUT OF TERMINALS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...POJORLIE LONG TERM...BUNKERS AVIATION...JC
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
335 AM CST THU DEC 4 2014 .DISCUSSION... LATEST SURFACE OBSERVATIONS SHOW COLD FRONT THAT HAS BEEN WAFFLING BACK AND FORTH ACROSS THE MID STATE HAS BECOME ILL DEFINED AND DIFFUSE IN THE VICINITY OF CENTRAL ALABAMA AND GEORGIA...WITH TEMPERATURES IN THE UPPER 30S AND 40S ACROSS OUR CWA. RADAR IMAGERY THIS MORNING SHOWS NUMEROUS SHOWERS HAVE DEVELOPED OVER THE MID STATE IN RESPONSE TO AN UPPER LEVEL SHORTWAVE APPARENT ON WATER VAPOR IMAGERY OVER THE SOUTHERN PLAINS. LATEST HRRR MODEL RUNS INDICATE ADDITIONAL SHOWERS WILL LIKELY DEVELOP LATER THIS MORNING OVER THE NORTHERN HALF OF THE CWA IN ASSOCIATION WITH THIS FEATURE BEFORE MOVING OUT BY AFTERNOON....WITH CLOUDY SKIES AND COOL CONDITIONS CONTINUING. AS ANOTHER SHORTWAVE APPROACHES OUR REGION FROM NORTHERN MEXICO LATER TODAY...FRONTAL BOUNDARY IS EXPECTED TO BECOME MORE DEFINED AND RETURN NORTHWARD AS A WARM FRONT...REACHING THE KY BORDER VICINITY BY 12Z FRIDAY PER 00Z GUIDANCE. DEWPOINTS IN THE 50S TO AROUND 60 ARE ANTICIPATED TO SPREAD NORTHWARD INTO MIDDLE TENNESSEE TONIGHT...RESULTING IN LOW TEMPERATURES LIKELY BEING REACHED THIS EVENING FOR MANY LOCATIONS THEN SLOWLY WARMING THROUGH THE NIGHT INTO FRIDAY. IN ADDITION...AFTER A LULL IN ACTIVITY THIS AFTERNOON AND EVENING...MORE SHOWERS SHOULD DEVELOP THURSDAY NIGHT WITH THE RETURNING BOUNDARY AND INCREASE IN LOW LEVEL MOISTURE. H5 SHORTWAVE PROGGED BY 00Z MODELS TO MOVE ACROSS THE REGION ON FRIDAY WITH A SECONDARY TROUGH AXIS SHIFTING THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY. TEMPERATURES SHOULD WARM SIGNIFICANTLY DURING THE DAY ON FRIDAY AS WARM FRONT MOVES OFF TO OUR NORTH...REACHING WELL INTO THE 60S TO AROUND 70 BY FRIDAY AFTERNOON. 00Z MODELS DEPICT A WEAK SURFACE LOW AND ASSOCIATED COLD FRONT DEVELOPING ACROSS THE SOUTHERN PLAINS THEN SHIFTING EASTWARD ACROSS THE OHIO/TENNESSEE VALLEYS FRIDAY NIGHT INTO EARLY SATURDAY. STRONG VERTICAL MOTION ASSOCIATED WITH THE SURFACE AND UPPER LEVEL FEATURES ALONG WITH THE PLENTIFUL LOW LEVEL MOISTURE AND WEAK ELEVATED INSTABILITY WILL ALLOW FOR NUMEROUS SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP DURING THIS TIME PERIOD. HAVE RAISED POPS FURTHER FOR THE FRIDAY THROUGH SATURDAY TIMEFRAME AS CONFIDENCE IN HIGH IN WIDESPREAD PRECIPITATION...ESPECIALLY FROM 06/00Z TO 06/12Z FRIDAY NIGHT. GFS/ECMWF/WPC QPF ALL VERY AGREEABLE ON THE MID STATE SEEING AROUND 1 TO 1.5 INCHES OF TOTAL RAINFALL FOR THIS TWO DAY PERIOD. COLD FRONT MOVING THROUGH EARLY IN THE DAY ON SATURDAY SHOULD CAUSE HIGHS TO OCCUR IN THE MORNING WITH TEMPERATURES FALLING THROUGH THE DAY. DRIER CP AIRMASS IN THE WAKE OF THE FRONT LOOKS TO FINALLY SWEEP OUR PERSISTENT LOW CLOUD COVER OUT BY SUNDAY. 00Z GFS/ECMWF CONTINUE TO SHOW VERY POOR RUN TO RUN CONSISTENCY WITH THE UPPER PATTERN FOR NEXT WEEK...BUT IN GENERAL NEAR TO BELOW NORMAL TEMPERATURES APPEAR LIKELY WITH NO POPS CURRENTLY ANTICIPATED. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 56 52 68 57 / 50 50 80 100 CLARKSVILLE 48 47 67 53 / 60 50 80 100 CROSSVILLE 55 51 62 54 / 40 40 60 100 COLUMBIA 62 53 66 57 / 20 40 70 100 LAWRENCEBURG 63 54 68 57 / 20 40 70 100 WAVERLY 55 51 67 55 / 50 50 80 100 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHAMBURGER
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
810 PM CST FRI DEC 5 2014 .UPDATE... COLD FRONT IS ABOUT HALFWAY THROUGH THE CWA THIS EVENING BUT MOST OF THE SHOWER ACTIVITY HAS DIMINISHED AS UPPER TROUGH PULLS FARTHER AWAY TO THE EAST. OUTSIDE OF AN ISOLATED SHOWER RIGHT ALONG THE FRONT...MOST AREAS WILL NOT SEE ANY RAIN. LOWERED POPS FOR THE REMAINDER OF THE EVENING AND CONFINED THEM TO A NARROW BAND RIGHT ALONG THE FRONT OVER THE EASTERN COUNTIES. OTHERWISE...ONLY SOME MINOR DOWNWARD TWEAKS IN LOW TEMPERATURES WERE NEEDED ACROSS THE NORTH AND NORTHWEST COUNTIES. DUNN && .AVIATION... /ISSUED 613 PM CST FRI DEC 5 2014/ A COLD FRONT THAT EXTENDED SOUTH OF A HUGO OKLAHOMA /KHHW/ TO JUST NORTH OF DFW TO JUST SOUTH OF STEPHENVILLE /KSEP/ AT 00Z WILL MOVE SOUTHEAST THROUGH THE REST OF THE METROPLEX TAF SITES DURING THE NEXT HOUR AND INTO THE WACO AREA AROUND 03Z. NORTHWEST WINDS OF 15 TO 20 KNOTS WILL OCCUR WITH FRONTAL PASSAGES...WITH WIND SPEEDS DECREASING TO AROUND 10 KNOTS A COUPLE OF HOURS BEHIND FRONT. MVFR CEILINGS WILL DEVELOP BEHIND THE FRONT BY 07Z IN THE METROPLEX...AND 09Z AT WACO. SOME IFR CONDITIONS ARE POSSIBLE 11-15Z. EXPECT VFR CONDITIONS TO RETURN BY 17Z SATURDAY. 58 && .PREV DISCUSSION... /ISSUED 339 PM CST FRI DEC 5 2014/ FOR TODAY...THE ONLY SIGNIFICANT CHANGE TO THE FORECAST FROM THE MORNING UPDATE WAS TO INCREASE POPS SLIGHTLY ALONG AND SOUTHEAST OF THE FORECAST POSITION OF THE COLD FRONT ACROSS THE CWA THROUGH TONIGHT. EARLY AFTERNOON RUNS OF THE HRRR CONSISTENTLY ADVERTISE A SCATTERED LINE OF SHOWERS DEVELOPING ALONG THE LEADING EDGE OF THE COLD FRONT AS IT MOVES ACROSS THE CWA. AT 20Z/2PM...THE SURFACE OBSERVATIONS INDICATED THAT THE LEADING EDGE OF THE COLD FRONT WAS LOCATED ALONG A LINE FROM ARDMORE TO BOWIE TO BRECKENRIDGE. EARLY AFTERNOON VISIBLE SATELLITE IMAGERY SHOWED A THIN LINE OF CUMULUS ORGANIZING ALONG THE FRONT...SUPPORTING THE HRRR FORECAST FOR STRONGER LIFT AND BETTER RAIN SHOWER CHANCES IN THE IMMEDIATE VICINITY OF THE FRONT. DESPITE THE INCREASE IN RAIN CHANCES IN THE SHORT TERM FORECAST...CONTINUE TO THINK CHANCES OF LIGHTNING ARE LOW. 19Z AIRCRAFT SOUNDINGS FROM KDFW AND KDAL AIRPORTS CONTINUE TO SHOW MID-LEVEL LAPSE RATES THAT ARE TOO STABLE TO SUPPORT FREE CONVECTION. LAPSE RATES HAVE INCREASED A BIT FROM 12Z...LIKELY DUE FROM DYNAMIC LIFT ASSOCIATED WITH A SHORTWAVE TROUGH LOCATED OVER OKLAHOMA EARLY THIS AFTERNOON ACCORDING TO WATER VAPOR SATELLITE IMAGERY. HOWEVER DUE TO THE POSITION OF THE SHORTWAVE TROUGH...THINK THAT THE EFFECTS OF DYNAMIC LIFT ON OUR MID-LEVEL LAPSE RATES HAVE ALREADY OCCURRED. AS A RESULT...LEFT PRECIPITATION ALONG THE FRONT THUNDERSTORM FREE THROUGH TONIGHT. WILL CERTAINLY CONTINUE TO MONITOR AIRCRAFT OBSERVATIONS THROUGH THIS EVENING...AND WILL UPDATE THE FORECAST IF IT LOOKS LIKE THUNDER IS BECOMING MORE LIKELY. SATURDAY...THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE ENTIRE FORECAST AREA BY SATURDAY MORNING...LEAVING COOLER AND MUCH DRIER AIR IN PLACE ACROSS THE REGION. ALTHOUGH THE COLD FRONT DOES NOT REPRESENT A STRONG CANADIAN AIRMASS...AFTER TODAY`S TEMPERATURES IN THE MID TO UPPER 70S...IT WILL CERTAINLY BE NOTICEABLY COOLER TOMORROW BEHIND THE FRONT. HIGHS ARE EXPECTED TO TOP OUT NEAR 60 DEGREES FOR MOST LOCATIONS...VERY CLOSE TO NORMAL HIGHS FOR THIS TIME OF YEAR. BETWEEN LOW-LEVEL DRY AIR ADVECTION BEHIND THE FRONT AND SHORTWAVE RIDGING ALOFT...MAINTAINED A DRY FORECAST FOR SATURDAY. SUNDAY...A RELATIVELY FAST MOVING SHORTWAVE TROUGH...CURRENTLY LOCATED ABOUT 800 MILES WEST OF BAJA CALIFORNIA...IS EXPECTED TO MOVE OVER THE SOUTHERN PLAINS SUNDAY AFTERNOON. WITH A LOW-LEVEL COOL AIRMASS STILL IN PLACE ACROSS THE CWA BEHIND TODAY`S FRONT...ALL MODEL GUIDANCE INDICATES THAT THIS SHORTWAVE TROUGH WILL RESULT IN STRONG WARM AIR ADVECTION OVER THE CWA ON SUNDAY. WARM AIR ADVECTION OVER THE COOL LOW-LEVEL AIRMASS DOES REPRESENT PERSISTENT LIFT...HOWEVER PRECIPITATION PROSPECTS FOR THE REGION LOOK VERY LIMITED AT THIS TIME. DESPITE NEARLY ALL MODELS SHOWING THE PERSISTENT LIFT ON SUNDAY...THE PROSPECTS FOR MOISTURE RETURN LOOK VERY LIMITED...AND FOCUSED ON LOCATIONS JUST WEST AND SOUTH OF THE CWA. AS A RESULT...WENT AHEAD AND BUMPED POPS DOWN 10 PERCENT ACROSS THE ENTIRE AREA THROUGHOUT THE DAY ON SUNDAY. THINK THAT OUR BEST CHANCES FOR LIGHT RAINFALL MAY BE WHEN THE SHORTWAVE TROUGH MOVES DIRECTLY OVERHEAD SUNDAY AFTERNOON. MODELS SHOW A BAND OF RELATIVELY STRONG MID-LEVEL FRONTOGENETIC FORCING MOVING OVER THE CWA RIGHT OUT AHEAD OF THE SHORTWAVE ON SUNDAY. THIS WILL LIKELY RESULT IN SOME ELEVATED PRECIPITATION...HOWEVER THE LOW-LEVEL AIRMASS LOOKS DRY ENOUGH THAT MOST OF THIS SHOULD EVAPORATE BEFORE REACHING THE SURFACE. AT ANY RATE...THE END RESULT WAS THAT ISOLATED RAIN SHOWERS WERE INCLUDED IN THE FORECAST EVEN WHERE POPS ARE AS LOW AS 10 PERCENT TO ACCOUNT FOR THIS VIRGA/LIGHT RAIN POTENTIAL. MONDAY INTO TUESDAY...IN GENERAL...A REINFORCING SHOT OF COOL AND DRY AIR WILL BUILD INTO THE AREA BEHIND SUNDAY`S SHORTWAVE TROUGH KEEPING US DRY ACROSS NORTH TEXAS FOR EARLY NEXT WEEK. THE LARGE SCALE UPPER AIR PATTERN IS EXPECTED TO BE DOMINATED BY LARGE TROUGHS OVER THE FAR EAST AND WEST COASTS...RESULTING IN BROAD RIDGING OR NEARLY ZONAL FLOW OVER THE CENTRAL PORTION OF THE COUNTRY. THIS PATTERN ALSO GENERALLY FAVORS DRY WEATHER FOR THE CWA...HOWEVER PERSISTENT WESTERLY FLOW ALOFT OVER THE CONUS ROCKIES WILL RESULT IN LEE-SIDE TROUGHING INCREASING IN INTENSITY THROUGHOUT THE WEEK. WITH LEE-SIDE TROUGHING DEVELOPING AND A COOL AIRMASS IN PLACE...WE WILL ONCE AGAIN HAVE A SITUATION WHERE WE HAVE SOUTHERLY FLOW ALOFT IMPINGING ON A COOL LOW-LEVEL AIRMASS NEAR THE SURFACE. THIS WILL RESULT IN PERSISTENT...ALBEIT WEAK...LIFT AND MOISTURE RETURN BY TUESDAY AFTERNOON. BACKED OFF ON POPS A BIT FROM THE PREVIOUS FORECAST ON TUESDAY...HOWEVER MAINTAINED SOME 20 POPS OVER THE FAR WESTERN CWA TUESDAY AFTERNOON...NEAREST TO THE LOW-LEVEL MOISTURE RETURN CONSISTENTLY ADVERTISED IN MEDIUM RANGE GUIDANCE. WEDNESDAY...MODELS ADVERTISE THAT THE UPPER LEVEL PATTERN WILL AMPLIFY WITH RIDGING BUILDING OVER THE CONUS ROCKIES IN RESPONSE TO A STRONG UPPER TROUGH BUILDING EASTWARD...FARTHER ON SHORE THE WESTERN CONUS COAST. THIS RESULTS IN NORTHWEST FLOW ALOFT OVER THE REGION ON WEDNESDAY...IN WHICH MODELS HAVE BEEN CONSISTENTLY SENDING A STRONG BUT COMPACT SHORTWAVE TROUGH SOUTHEAST THROUGH THE CWA OVER THE PAST COUPLE OF DAYS. THIS TROUGH IS EXPECTED TO REMAIN WELL NORTH OF NORTH TEXAS...BUT SHOULD HELP SPREAD SOME OF THE MOISTURE RETURN FROM WEST TEXAS EASTWARD OVER THE CWA ON WEDNESDAY. IF MOISTURE DOES SPREAD EAST AS ADVERTISED AND LOW- LEVEL WARM AIR ADVECTION AND ISENTROPIC LIFT CONTINUES... LIGHT RAIN SHOWERS WILL LIKELY SPREAD ACROSS THE ENTIRE CWA ON WEDNESDAY. BECAUSE LIFT IS EXPECTED TO REMAIN WEAK...RAIN SHOWERS SHOULD BE SPOTTY/HIT-AND-MISS ON WEDNESDAY. THURSDAY AND FRIDAY...MODELS INDICATE THAT LOW-LEVEL WARM AIR ADVECTION PERSISTS...HOWEVER MODELS ARE ALSO BRINGING THE UPPER LEVEL RIDGE OUT FROM THE CONUS ROCKIES AND OVER THE GREAT PLAINS FOR THE LATTER PART OF THE WEEK. DESPITE PERSISTENT LOW-LEVEL LIFT...WILL FAVOR THE UPPER LEVEL RIDGING IN THIS FORECAST AND KEEP THURSDAY AND FRIDAY DRY FOR NOW AS MID AND UPPER LEVEL FORCING SHOULD BE DOMINATED BY SUBSIDENCE. NEXT WEEKEND...MODELS ARE DEFINITELY STRUGGLING WITH RUN TO RUN AND MODEL TO MODEL CONSISTENCY WITH REGARDS TO THE EVOLUTION OF THE STRONG WEST COAST UPPER TROUGH. HOWEVER...MODELS HAVE BEEN CONSISTENTLY BRINGING THIS TROUGH OVER THE PLAINS NEXT WEEKEND...WHICH MAY RESULT IN SOME DECENT RAIN CHANCES FOR THE REGION. THIS IS CURRENTLY BEYOND THE VALID FORECAST PERIOD...BUT IT IS A SYSTEM THAT WE WILL BE KEEPING A CLOSE EYE ON IN THE COMING DAYS. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 49 61 44 57 43 / 5 5 5 10 10 WACO, TX 51 63 46 57 43 / 10 10 10 20 20 PARIS, TX 49 60 42 56 39 / 20 10 5 10 10 DENTON, TX 45 60 42 56 41 / 5 5 5 10 5 MCKINNEY, TX 45 60 42 57 40 / 5 5 5 10 10 DALLAS, TX 50 61 45 56 44 / 5 5 5 10 10 TERRELL, TX 49 62 44 58 40 / 10 5 5 10 10 CORSICANA, TX 52 63 45 59 43 / 20 10 10 20 20 TEMPLE, TX 51 64 46 58 44 / 10 10 10 20 20 MINERAL WELLS, TX 45 60 42 56 42 / 0 5 10 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
613 PM CST FRI DEC 5 2014 .AVIATION... A COLD FRONT THAT EXTENDED SOUTH OF A HUGO OKLAHOMA /KHHW/ TO JUST NORTH OF DFW TO JUST SOUTH OF STEPHENVILLE /KSEP/ AT 00Z WILL MOVE SOUTHEAST THROUGH THE REST OF THE METROPLEX TAF SITES DURING THE NEXT HOUR AND INTO THE WACO AREA AROUND 03Z. NORTHWEST WINDS OF 15 TO 20 KNOTS WILL OCCUR WITH FRONTAL PASSAGES...WITH WIND SPEEDS DECREASING TO AROUND 10 KNOTS A COUPLE OF HOURS BEHIND FRONT. MVFR CEILINGS WILL DEVELOP BEHIND THE FRONT BY 07Z IN THE METROPLEX...AND 09Z AT WACO. SOME IFR CONDITIONS ARE POSSIBLE 11-15Z. EXPECT VFR CONDITIONS TO RETURN BY 17Z SATURDAY. 58 && .PREV DISCUSSION... /ISSUED 339 PM CST FRI DEC 5 2014/ FOR TODAY...THE ONLY SIGNIFICANT CHANGE TO THE FORECAST FROM THE MORNING UPDATE WAS TO INCREASE POPS SLIGHTLY ALONG AND SOUTHEAST OF THE FORECAST POSITION OF THE COLD FRONT ACROSS THE CWA THROUGH TONIGHT. EARLY AFTERNOON RUNS OF THE HRRR CONSISTENTLY ADVERTISE A SCATTERED LINE OF SHOWERS DEVELOPING ALONG THE LEADING EDGE OF THE COLD FRONT AS IT MOVES ACROSS THE CWA. AT 20Z/2PM...THE SURFACE OBSERVATIONS INDICATED THAT THE LEADING EDGE OF THE COLD FRONT WAS LOCATED ALONG A LINE FROM ARDMORE TO BOWIE TO BRECKENRIDGE. EARLY AFTERNOON VISIBLE SATELLITE IMAGERY SHOWED A THIN LINE OF CUMULUS ORGANIZING ALONG THE FRONT...SUPPORTING THE HRRR FORECAST FOR STRONGER LIFT AND BETTER RAIN SHOWER CHANCES IN THE IMMEDIATE VICINITY OF THE FRONT. DESPITE THE INCREASE IN RAIN CHANCES IN THE SHORT TERM FORECAST...CONTINUE TO THINK CHANCES OF LIGHTNING ARE LOW. 19Z AIRCRAFT SOUNDINGS FROM KDFW AND KDAL AIRPORTS CONTINUE TO SHOW MID-LEVEL LAPSE RATES THAT ARE TOO STABLE TO SUPPORT FREE CONVECTION. LAPSE RATES HAVE INCREASED A BIT FROM 12Z...LIKELY DUE FROM DYNAMIC LIFT ASSOCIATED WITH A SHORTWAVE TROUGH LOCATED OVER OKLAHOMA EARLY THIS AFTERNOON ACCORDING TO WATER VAPOR SATELLITE IMAGERY. HOWEVER DUE TO THE POSITION OF THE SHORTWAVE TROUGH...THINK THAT THE EFFECTS OF DYNAMIC LIFT ON OUR MID-LEVEL LAPSE RATES HAVE ALREADY OCCURRED. AS A RESULT...LEFT PRECIPITATION ALONG THE FRONT THUNDERSTORM FREE THROUGH TONIGHT. WILL CERTAINLY CONTINUE TO MONITOR AIRCRAFT OBSERVATIONS THROUGH THIS EVENING...AND WILL UPDATE THE FORECAST IF IT LOOKS LIKE THUNDER IS BECOMING MORE LIKELY. SATURDAY...THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE ENTIRE FORECAST AREA BY SATURDAY MORNING...LEAVING COOLER AND MUCH DRIER AIR IN PLACE ACROSS THE REGION. ALTHOUGH THE COLD FRONT DOES NOT REPRESENT A STRONG CANADIAN AIRMASS...AFTER TODAY`S TEMPERATURES IN THE MID TO UPPER 70S...IT WILL CERTAINLY BE NOTICEABLY COOLER TOMORROW BEHIND THE FRONT. HIGHS ARE EXPECTED TO TOP OUT NEAR 60 DEGREES FOR MOST LOCATIONS...VERY CLOSE TO NORMAL HIGHS FOR THIS TIME OF YEAR. BETWEEN LOW-LEVEL DRY AIR ADVECTION BEHIND THE FRONT AND SHORTWAVE RIDGING ALOFT...MAINTAINED A DRY FORECAST FOR SATURDAY. SUNDAY...A RELATIVELY FAST MOVING SHORTWAVE TROUGH...CURRENTLY LOCATED ABOUT 800 MILES WEST OF BAJA CALIFORNIA...IS EXPECTED TO MOVE OVER THE SOUTHERN PLAINS SUNDAY AFTERNOON. WITH A LOW-LEVEL COOL AIRMASS STILL IN PLACE ACROSS THE CWA BEHIND TODAY`S FRONT...ALL MODEL GUIDANCE INDICATES THAT THIS SHORTWAVE TROUGH WILL RESULT IN STRONG WARM AIR ADVECTION OVER THE CWA ON SUNDAY. WARM AIR ADVECTION OVER THE COOL LOW-LEVEL AIRMASS DOES REPRESENT PERSISTENT LIFT...HOWEVER PRECIPITATION PROSPECTS FOR THE REGION LOOK VERY LIMITED AT THIS TIME. DESPITE NEARLY ALL MODELS SHOWING THE PERSISTENT LIFT ON SUNDAY...THE PROSPECTS FOR MOISTURE RETURN LOOK VERY LIMITED...AND FOCUSED ON LOCATIONS JUST WEST AND SOUTH OF THE CWA. AS A RESULT...WENT AHEAD AND BUMPED POPS DOWN 10 PERCENT ACROSS THE ENTIRE AREA THROUGHOUT THE DAY ON SUNDAY. THINK THAT OUR BEST CHANCES FOR LIGHT RAINFALL MAY BE WHEN THE SHORTWAVE TROUGH MOVES DIRECTLY OVERHEAD SUNDAY AFTERNOON. MODELS SHOW A BAND OF RELATIVELY STRONG MID-LEVEL FRONTOGENETIC FORCING MOVING OVER THE CWA RIGHT OUT AHEAD OF THE SHORTWAVE ON SUNDAY. THIS WILL LIKELY RESULT IN SOME ELEVATED PRECIPITATION...HOWEVER THE LOW-LEVEL AIRMASS LOOKS DRY ENOUGH THAT MOST OF THIS SHOULD EVAPORATE BEFORE REACHING THE SURFACE. AT ANY RATE...THE END RESULT WAS THAT ISOLATED RAIN SHOWERS WERE INCLUDED IN THE FORECAST EVEN WHERE POPS ARE AS LOW AS 10 PERCENT TO ACCOUNT FOR THIS VIRGA/LIGHT RAIN POTENTIAL. MONDAY INTO TUESDAY...IN GENERAL...A REINFORCING SHOT OF COOL AND DRY AIR WILL BUILD INTO THE AREA BEHIND SUNDAY`S SHORTWAVE TROUGH KEEPING US DRY ACROSS NORTH TEXAS FOR EARLY NEXT WEEK. THE LARGE SCALE UPPER AIR PATTERN IS EXPECTED TO BE DOMINATED BY LARGE TROUGHS OVER THE FAR EAST AND WEST COASTS...RESULTING IN BROAD RIDGING OR NEARLY ZONAL FLOW OVER THE CENTRAL PORTION OF THE COUNTRY. THIS PATTERN ALSO GENERALLY FAVORS DRY WEATHER FOR THE CWA...HOWEVER PERSISTENT WESTERLY FLOW ALOFT OVER THE CONUS ROCKIES WILL RESULT IN LEE-SIDE TROUGHING INCREASING IN INTENSITY THROUGHOUT THE WEEK. WITH LEE-SIDE TROUGHING DEVELOPING AND A COOL AIRMASS IN PLACE...WE WILL ONCE AGAIN HAVE A SITUATION WHERE WE HAVE SOUTHERLY FLOW ALOFT IMPINGING ON A COOL LOW-LEVEL AIRMASS NEAR THE SURFACE. THIS WILL RESULT IN PERSISTENT...ALBEIT WEAK...LIFT AND MOISTURE RETURN BY TUESDAY AFTERNOON. BACKED OFF ON POPS A BIT FROM THE PREVIOUS FORECAST ON TUESDAY...HOWEVER MAINTAINED SOME 20 POPS OVER THE FAR WESTERN CWA TUESDAY AFTERNOON...NEAREST TO THE LOW-LEVEL MOISTURE RETURN CONSISTENTLY ADVERTISED IN MEDIUM RANGE GUIDANCE. WEDNESDAY...MODELS ADVERTISE THAT THE UPPER LEVEL PATTERN WILL AMPLIFY WITH RIDGING BUILDING OVER THE CONUS ROCKIES IN RESPONSE TO A STRONG UPPER TROUGH BUILDING EASTWARD...FARTHER ON SHORE THE WESTERN CONUS COAST. THIS RESULTS IN NORTHWEST FLOW ALOFT OVER THE REGION ON WEDNESDAY...IN WHICH MODELS HAVE BEEN CONSISTENTLY SENDING A STRONG BUT COMPACT SHORTWAVE TROUGH SOUTHEAST THROUGH THE CWA OVER THE PAST COUPLE OF DAYS. THIS TROUGH IS EXPECTED TO REMAIN WELL NORTH OF NORTH TEXAS...BUT SHOULD HELP SPREAD SOME OF THE MOISTURE RETURN FROM WEST TEXAS EASTWARD OVER THE CWA ON WEDNESDAY. IF MOISTURE DOES SPREAD EAST AS ADVERTISED AND LOW- LEVEL WARM AIR ADVECTION AND ISENTROPIC LIFT CONTINUES... LIGHT RAIN SHOWERS WILL LIKELY SPREAD ACROSS THE ENTIRE CWA ON WEDNESDAY. BECAUSE LIFT IS EXPECTED TO REMAIN WEAK...RAIN SHOWERS SHOULD BE SPOTTY/HIT-AND-MISS ON WEDNESDAY. THURSDAY AND FRIDAY...MODELS INDICATE THAT LOW-LEVEL WARM AIR ADVECTION PERSISTS...HOWEVER MODELS ARE ALSO BRINGING THE UPPER LEVEL RIDGE OUT FROM THE CONUS ROCKIES AND OVER THE GREAT PLAINS FOR THE LATTER PART OF THE WEEK. DESPITE PERSISTENT LOW-LEVEL LIFT...WILL FAVOR THE UPPER LEVEL RIDGING IN THIS FORECAST AND KEEP THURSDAY AND FRIDAY DRY FOR NOW AS MID AND UPPER LEVEL FORCING SHOULD BE DOMINATED BY SUBSIDENCE. NEXT WEEKEND...MODELS ARE DEFINITELY STRUGGLING WITH RUN TO RUN AND MODEL TO MODEL CONSISTENCY WITH REGARDS TO THE EVOLUTION OF THE STRONG WEST COAST UPPER TROUGH. HOWEVER...MODELS HAVE BEEN CONSISTENTLY BRINGING THIS TROUGH OVER THE PLAINS NEXT WEEKEND...WHICH MAY RESULT IN SOME DECENT RAIN CHANCES FOR THE REGION. THIS IS CURRENTLY BEYOND THE VALID FORECAST PERIOD...BUT IT IS A SYSTEM THAT WE WILL BE KEEPING A CLOSE EYE ON IN THE COMING DAYS. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 50 61 44 57 43 / 10 5 5 10 10 WACO, TX 51 63 46 57 43 / 30 10 10 20 20 PARIS, TX 49 60 42 56 39 / 30 10 5 10 10 DENTON, TX 46 60 42 56 41 / 10 5 5 10 5 MCKINNEY, TX 48 60 42 57 40 / 20 5 5 10 10 DALLAS, TX 50 61 45 56 44 / 20 5 5 10 10 TERRELL, TX 52 62 44 58 40 / 30 5 5 10 10 CORSICANA, TX 53 63 45 59 43 / 30 10 10 20 20 TEMPLE, TX 50 64 46 58 44 / 30 10 10 20 20 MINERAL WELLS, TX 44 60 42 56 42 / 10 5 10 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/91
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1138 PM CST WED DEC 3 2014 .UPDATE... PLEASE SEE 06Z AVIATION DISCUSSION BELOW. && .AVIATION... WIDESPREAD MVFR CONDITIONS ONGOING WITH EXPECTED DETERIORATION TO IFR AND PERIODIC LIFR TO VLIFR ALSO POSSIBLE TOWARDS DAWN DUE TO LOW CIGS AND REDUCED VISIBILITIES. KSAT/KSSF HAVE GREATEST LIKELIHOOD OF SOME DENSE FOG 12-14Z WITH KAUS SLIGHTLY LESS WITH VIS DROPS TO 1SM POSSIBLE. KDRT VIS MAY STAY HIGHER THEN MOST SITES DUE TO STRONGER WINDS BUT CIGS SHOULD STILL DROP TO LESS THAN 500FT. PERIODIC LIGHT DRIZZLE WILL ALSO BE LIKELY THROUGH THE OVERNIGHT. ONLY MARGINAL IMPROVEMENT EXPECTED THROUGH DAY THURSDAY TO MVFR WITH A NEAR REPEAT OF FALLING CATEGORIES THURSDAY NIGHT INTO FRIDAY. /ALLEN/ && .PREV DISCUSSION... /ISSUED 1001 PM CST WED DEC 3 2014/ UPDATE... /SLIGHTLY WARMER MIN TEMPS SE/ DEW POINTS ARE HOVERING AROUND 60 OVER THE COASTAL PRAIRIES...AND THE HRRR SUGGESTS WARMER MIN TEMPERATURES THAT MATCH UP WELL WITH OBSERVATIONAL TRENDS. THUS WILL RAISE MINS A FEW DEGREES FOR TONIGHT OVER THE COASTAL PRAIRIES. THE REST OF THE OBSERVATIONAL TRENDS LOOK ON TRACK. AREAS OF DENSE FOG WILL REMAIN A POSSIBILITY...BUT WITH A LOT OF VARIETY IN VISIBILITIES THIS EVENING FROM ONE AREA TO THE NEXT...WILL NOT PLAN ON ANY NPW ISSUANCES FOR THE NEXT FEW HOURS. PREV DISCUSSION... /ISSUED 345 PM CST WED DEC 3 2014/ SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)... SOME BREAKS IN THE CLOUD COVER CAN BE OBSERVED ACROSS SOUTH CENTRAL TEXAS LATE THIS AFTERNOON. HOWEVER...MOST OF THE REGION CONTINUES TO REMAIN OVERCAST. TEMPERATURES HAVE WARMED INTO THE LOW 60S TO NEAR 70 IN AREAS WHERE SKIES HAVE PARTIALLY CLEARED. ELSEWHERE... TEMPERATURES REMAIN IN THE 50S. CLOUD COVER WILL THICKEN OVERNIGHT AS WARM AIR ADVECTION IN THE LOW-LEVELS CONTINUES. WE EXPECT FOG AND DRIZZLE TO BECOME WIDESPREAD TONIGHT... ESPECIALLY ALONG AND WEST OF THE ESCARPMENT. CAN/T RULE OUT THE POSSIBILITY OF DENSE FOG FOR AREAS NORTH OF A ROCKSPRINGS TO UVALDE TO SAN ANTONIO TO AUSTIN LINE. WE/LL MENTION FOG BECOMING WIDESPREAD IN THE HAZARDOUS WEATHER OUTLOOK FOR TONIGHT. LATER SHIFTS MAY NEED TO ISSUE A DENSE FOG ADVISORY PENDING OBSERVATIONAL TRENDS AND 00Z MODEL GUIDANCE. FOG IS LIKELY TO CONTINUE WELL INTO THURSDAY MORNING GIVEN CONTINUED MOISTENING OF THE LOW-LEVELS. OTHERWISE...TEMPERATURES WILL WARM ON THURSDAY... BUT WE DID UNDERCUT GUIDANCE SLIGHTLY IN AREAS WHERE CLOUD COVER IS LIKELY TO LINGER THROUGH THE AFTERNOON HOURS. LONG TERM (FRIDAY THROUGH WEDNESDAY)... CLOUD COVER REMAINS PLENTIFUL INTO FRIDAY...ALTHOUGH SOME BREAKS ARE EXPECTED WEST OF I-35 DURING THE AFTERNOON. WE/LL CONTINUE TO MENTION A 20-30% CHANCE FOR RAIN AS THE SOUTHERN PERIPHERY OF AN UPPER LEVEL TROUGH TRAVERSES THE AREA. CAN/T COMPLETELY RULE OUT A THUNDERSTORM OR TWO AS TEMPERATURES WARM INTO THE 70S...BUT ONLY ISOLATED STORMS EXPECTED. A COLD FRONT WILL MOVE THROUGH ON SATURDAY AND THIS WILL KNOCK TEMPERATURES BACK DOWN CLOSER TO CLIMATOLOGICAL NORMALS FOR SATURDAY THROUGH MONDAY. WE/LL ALSO CONTINUE TO MENTION A 20-40% CHANCE FOR SHOWERS THROUGH THE WEEKEND INTO EARLY NEXT WEEK ACROSS MOST AREAS AS THE COLD FRONT AND AN UPPER LEVEL TROUGH SHOULD BE ENOUGH TO GIN UP SOME SHOWERS. LATE IN THE FORECAST PERIOD...THE OPERATIONAL GFS AND ECMWF CONTINUE TO DIFFER WITH REGARDS TO THE NEXT COLD FRONT DURING THE EARLY/MIDDLE PORTION OF THE UPCOMING WEEK. THE ECMWF SHOWS MUCH DRIER AIR FILTERING IN FROM THE NORTH ON TUESDAY AND WEDNESDAY WHILE THE GFS KEEPS THE DRIER AIR FARTHER EAST OF OUR REGION. THE GFS DOES SHOW THE MOIST AXIS BEGINNING TO FOCUS ACROSS OUR WESTERN ZONES AND WE/LL BEGIN SHIFT RAIN CHANCES INTO THE WESTERN HILL COUNTRY... SOUTHERN EDWARDS PLATEAU AND RIO GRANDE PLAINS ON TUESDAY. WE COULD SEE RAIN CHANCES LINGER INTO WEDNESDAY AS YET ANOTHER UPPER LEVEL SYSTEM MOVES IN FROM THE NORTHWEST. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 58 67 61 74 57 / 20 20 30 30 20 AUSTIN BERGSTROM INTL AIRPORT 57 68 61 74 57 / 20 20 30 30 20 NEW BRAUNFELS MUNI AIRPORT 58 68 62 75 58 / 20 20 20 30 20 BURNET MUNI AIRPORT 55 65 58 73 52 / 20 20 30 30 20 DEL RIO INTL AIRPORT 57 67 58 73 54 / 10 10 20 10 10 GEORGETOWN MUNI AIRPORT 56 66 60 73 55 / 20 20 30 30 20 HONDO MUNI AIRPORT 56 67 60 73 56 / 20 20 20 20 20 SAN MARCOS MUNI AIRPORT 58 68 61 74 57 / 20 20 20 30 20 LA GRANGE - FAYETTE REGIONAL 59 70 62 75 60 / 20 20 20 30 30 SAN ANTONIO INTL AIRPORT 57 68 63 74 59 / 20 20 20 20 20 STINSON MUNI AIRPORT 58 69 62 75 60 / 20 20 20 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...15 SYNOPTIC/GRIDS...18 PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1122 PM CST WED DEC 3 2014 .AVIATION... /06Z TAFS/ CONCERNS...CIGS WILL LOWER INTO IFR/LIFR CATEGORY OVERNIGHT AND AGAIN THURSDAY NIGHT. CONDITIONS AT THE TAF SITES ARE EXPECTED TO DETERIORATE OVERNIGHT AS MOISTURE CONTINUES TO INCREASE ACROSS THE REGION. EXPECT THE TAF SITES TO BE IN LOW IFR OR LIFR CATEGORY BY 10-11Z AND REMAIN THERE THROUGH MOST OF THE MORNING HOURS. THE CATEGORY REDUCTIONS WILL BE DUE TO A COMBINATION OF LOW CIGS...FOG...AND DRIZZLE. LIGHT RAIN MAY BRIEFLY AFFECT ANY OF THE TAF SITES THROUGH THE OVERNIGHT AND THURSDAY MORNING HOURS. CONDITIONS WILL SLOWLY IMPROVE TO MVFR CATEGORY THURSDAY AFTERNOON BUT RETURN BELOW 2 KFT IN THE EVENING HOURS AND THEN FALL BELOW 1 KFT DURING THE OVERNIGHT HOURS WITH FOG AND DRIZZLE RETURNING. 82/JLD && .UPDATE... WIDESPREAD FOG CONTINUES TO REDUCE VISIBILITIES INTO THE 1 TO 3 MILE RANGE ALONG AND NORTH OF A BOWIE TO GREENVILLE TO SULPHUR SPRINGS LINE THIS EVENING. EXPECT ADDITIONAL AREAS OF FOG TO DEVELOP ACROSS THE FORECAST AREA OVERNIGHT. A WEAK FRONTAL BOUNDARY EXTENDS NORTH OF A GRAHAM TO MCKINNEY TO QUITMAN LINE WITH LIGHT EAST TO NORTHEAST WINDS TO THE NORTH OF THE BOUNDARY AND LIGHT SOUTHEASTERLY WINDS TO THE SOUTH. THE RAP STALLS THIS BOUNDARY THIS EVENING AND THEN LIFTS IT INTO SOUTHERN OKLAHOMA BEFORE DAYBREAK. THERE IS A POTENTIAL FOR SOME LOCALLY DENSE FOG ALONG THE RED RIVER COUNTIES. FOR NOW HAVE PLACED 3/4SM FOG IN THE GRIDS FOR THOSE AREAS...AND WILL MONITOR THE POTENTIAL FOR DENSE FOG. HAVE LOWERED POPS KEEPING THE HIGHEST CHANCES OVERNIGHT...30 TO 40 PERCENT ALONG THE RED RIVER...WITH 20S ACROSS MOST OF THE REST OF THE AREA. UPDATES HAVE BEEN SENT. 58 && .PREV DISCUSSION... /ISSUED ISSUED BY NATIONAL WEATHER SERVICE SHREVEPORT LA/ CLOUDS HANGING TOUGH TODAY BUT SOME BREAKS WERE NOTED WEST OF AN RPH...COM LINE LATE THIS AFTERNOON. WHERE THESE BREAKS WERE OCCURRING...TEMPERATURES HAD WARMED INTO THE MID TO UPPER 60S OUT NEAR ABI AND SJT. CLOSER TO HOME...LOWER 60S WERE COMMON ACROSS OR SOUTHERN ZONES WITH NEAR TO LOWER 50S ALONG THE RED RIVER ALONG OUR RESIDUAL FRONTAL BOUNDARY. THIS BOUNDARY HAS SHOWN A TENDENCY TO PIVOT SLOWLY SOUTHWARD...` ESPECIALLY ALONG THE UPPER RED RIVER VALLEY AS TEMPERATURES HAVE SLOWLY FALLEN ALL DAY ALONG AND NORTH OF A CDS TO FDR LINE. SHORT TERM PROGS HAVE A GOOD HANDLE ON THIS BOUNDARY CONTINUING TO SLOWLY SINK SOUTHWARD TOWARDS THE I-20 CORRIDOR NEAR AND WEST OF ABI...BUT PIVOTING SLOWLY BACK NORTH OF THE RED RIVER EAST OF GYI LATE TONIGHT. THIS WILL KEEP MUCH OF OUR CWA UNDER THE INFLUENCE OF CONTINUED WAA AND LOW LEVEL CONDENSATION PRESSURE DEFICITS SUPPORT THE POSSIBILITY OF DRIZZLE AND/OR THE DEVELOPMENT OF PATCHY FOG. SLIGHTLY INCREASED LIFT ALONG AND NORTH OF THE I-30 CORRIDOR WILL SUPPORT A LITTLE INCREASED CHANCE OF PRECIPITATION OVERNIGHT AS WELL. NEARLY ZONAL UPPER FLOW OVERNIGHT THROUGH EARLY THURSDAY WILL BECOME MORE WSW AS THE FIRST IN A SERIES OF DISTURBANCES MOVES OUT OF THE FOUR CORNER REGION AND INTO THE HILL COUNTRY/SOUTHERN PLAINS. SHOULD SEE INCREASED CHANCES OF PRECIPITATION...SOME OF THAT CONVECTIVE IN NATURE LATE ON THURSDAY...BUT ESPECIALLY THU NIGHT INTO EARLY FRI BEFORE THE PRECIPITATION MOVES EAST OF THE REGION ON SAT. WEAK RIDGING COMMENCES FOR SATURDAY BUT YET ANOTHER SHORTWAVE WILL APPROACH THE REGION SATURDAY NIGHT INTO SUNDAY. MOISTURE RETURN MAY BE A PROBLEM WITH SUNDAY`S SYSTEM BUT CHANCE POPS ARE WARRANTED FOR AT LEAST OUR SW HALF ATTM. REALLY NOT SEEING ANY INTRUSIONS OF VERY COLD AIR THROUGH THE FORECAST PERIOD AND FOR THAT MATTER...THROUGH THE NEXT 10 DAYS. IF THE ECMWF IS TO BE BELIEVED...A BLOCKING RIDGE OF HIGH PRESSURE ALOFT BUILDS INTO THE PLAINS BY THE END OF NEXT WEEK WHICH IS A DRY AND STABLE PATTERN FOR NORTH TEXAS WITH NEAR SEASONABLE TEMPERATURES. PRELIM TO FOLLOW...99. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 53 65 58 73 52 / 20 20 40 40 30 WACO, TX 54 67 58 73 51 / 20 20 30 30 30 PARIS, TX 48 61 54 68 52 / 40 30 50 50 40 DENTON, TX 52 64 55 72 47 / 20 30 40 40 30 MCKINNEY, TX 52 63 55 71 49 / 20 30 40 50 30 DALLAS, TX 53 65 59 72 52 / 20 20 40 40 30 TERRELL, TX 53 67 57 71 52 / 20 20 40 50 40 CORSICANA, TX 53 69 58 72 54 / 20 20 30 40 30 TEMPLE, TX 54 68 57 73 52 / 10 20 30 30 20 MINERAL WELLS, TX 53 65 55 72 47 / 20 20 30 20 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 82/58
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
111 PM EST THU DEC 4 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD SOUTHWARD ACROSS THE PIEDMONT TO WEDGE AGAINST THE EASTERN FACE OF THE APPALACHIANS. A SERIES OF UPPER LEVEL DISTURBANCES WILL PASS ACROSS THE REGION THROUGH TONIGHT. A DEEP LOW PRESSURE SYSTEM WILL PASS ACROSS THE AREA SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1255 PM EST THURSDAY... RADAR SHOWING RAIN...MAYBE SOME SLEET MOVING ACROSS THE MTNS OF SW VA INTO WV. THE LATEST HRRR AND 12Z RNK WRF HANDLING THIS WELL. THIS IS ASSOCIATED WITH SHORTWAVE PASSING ACROSS KY AND INVERTED TROUGH ACROSS THE SRN APPALACHIANS. INCREASING TIMING FOR RAIN TO THE NORTH AND EAST...WITH INCREASING POPS. AMOUNTS WILL BE UNDER A QUARTER INCH...WITH THE HIGHER AMOUNTS OVER THE MTNS. NOT REALLY EXPECTING ANY FROZEN/FREEZING ISSUES THIS AFTERNOON AS TEMPS STAY IN THE UPPER 30S NORTHWEST TO MID 50S SOUTHEAST. WILL CONTINUE TO MAKE ADJUSTMENTS INTO TONIGHT/FRIDAY...AS MODELS SHOWING LESS THREAT OF PRECIP TO THE SRN CWA WITH MAIN BATCH ARRIVING ACROSS CENTRAL WV INTO THE ALLEGHANY HIGHLANDS AND SHENANDOAH VALLEY OVERNIGHT. WINTER WX HEADLINES MAY BE NEEDED FOR BATH COUNTY...BUT WILL LOOK MORE INTO THIS AS WE HEAD INTO 3-4 PM ISSUANCE OF FORECAST. PREVIOUS VALID DISCUSSION... POCKETS OF MIXED PRECIPITATION STILL APPEAR LIKELY BEGINNING AS EARLY AS 8 PM THIS EVENING IN THE VICINITY OF THE INTERSTATE 64 CORRIDOR. THE HIGH PRESSURE WEDGE WILL CONTINUE TO STRENGTHEN THROUGH THE NIGHT...FORCING INCREASINGLY COLDER AIR INTO OUR AREA FOR THE RAIN TO FALL INTO. WHILE TEMPERATURES WILL REMAIN WARM ENOUGH MOST LOCATIONS THAT PRECIPITATION WILL REMAIN LIQUID...SOME OF THE RIDGELINES WILL BE TRAPPED IN THE SUB-FREEZING AIR THAT MOVES IN LATE TONIGHT. IN THESE LOCATIONS...WILL START OFF WITH A FEW AREAS OF SLEET...WHICH WILL TRANSITION TO LIGHT FREEZING RAIN TOWARD DAWN ON FRIDAY. ICING ACCUMULATIONS ARE EXPECTED TO BE LIGHT AND SPOTTY...GENERALLY LESS THAN A TENTH OF AN INCH...AND MAINLY ON ELEVATED OBJECTS...ALTHOUGH ROADS MAY BECOME SLICK IN A FEW SPOTS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EST THURSDAY... COLD AIR WILL BE DAMMED AGAINST THE EASTERN SLOPES OF THE APPALACHIANS FRIDAY PER 1040 MB SURFACE HIGH OVER NEW ENGLAND. THIS AIRMASS WILL BE HARD TO DISPLACE...LEAVING US WITH A COOL CLOUDY DAY REINFORCED BY AN EAST OR NORTHEAST WIND. ABOVE THE WEDGE OF COOL AIR...WINDS WILL BE OUT OF THE SOUTHWEST...WARM/MOIST AIR BEING DRAWN NORTHEAST FROM THE GULF OF MEXICO. 850 TEMPS ARE PROGGED TO BE IN THE +6 TO +8 DEG C RANGE...SO HYDROMETEORS SHOULD FALL AS LIQUID. ANY P-TYPE ISSUES WILL BE EARLY FRIDAY MORNING PER SURFACE TEMPERATURES NEAR 32 DEGREES IN THE NORTHEASTERN CWA...VA/WV HIGHLANDS AND THE BLUE RIDGE PARKWAY NORTHEAST OF ROANOKE...WITH POCKETS OF FREEZING RAIN RESULTING IN SOME LIGHT ICE ACCRETIONS MAINLY IN THE TREES AND ON ELEVATED SURFACES. ASIDE FROM THIS PTYPE ISSUE IN THE MORNING...NO SIGNIFICANT CONCERNS NOTED FOR THE AFTERNOON WITH JUST A CONTINUED THREAT FOR LIGHT RAIN OR DRIZZLE. MODEL TEMPERATURE GUIDANCE HAS FINALLY COME AROUND TO RECOGNIZING THE COLD WEDGE FRIDAY...KEEPING ALL AREAS...WITH THE EXCEPTION OF AREAS WEST OF THE APPALACHIAN DIVIDE...ANCHORED IN THE 30S/40S THROUGHOUT THE DAY. WEDGE IS EXPECTED TO HOLD THROUGH FRIDAY NIGHT WITH COOL BUT STEADY TEMPERATURES. WENT WITH THE COOLER MET/NAM GUIDANCE...HOLDING OFF ON ANY MIX DOWN OF WARM AIR ALOFT UNTIL SATURDAY. FORECAST MODELS ARE GENERALLY TOO AGGRESSIVE MIXING OUT THE COOL WEDGE...AND GIVEN THE STRENGTH OF THE SFC HIGH OVER NEW ENGLAND SEE NO REASON TO DEVIATE. OTHER THAN SOME WEAK ISENTROPIC LIFT FRIDAY AFTERNOON AND FRIDAY NIGHT...ANY PRECIP SHOULD BE LIGHT...IN THE FORM OF LIGHT RAIN OR DRIZZLE...QPF LESS THAN A QUARTER OF AN INCH FRIDAY/FRIDAY NIGHT. BY SATURDAY...DYNAMIC LIFT WILL INCREASE YIELDING HIGHER PRECIPITATION RATES PER DEVELOPMENT AND PROGRESSION OF LOW PRESSURE WHICH WILL PASS OVER/NEAR THE AREA. MODELS ARE IN GENERAL AGREEMENT THAT SHORT WAVE ENERGY EXITING THE SOUTHWEST CONUS COURTESY OF AN ACTIVE SOUTHERN JET STREAM WILL RESULT IN THE DEVELOPMENT OF LOW PRESSURE OVER THE MID MS VALLEY FRIDAY NIGHT...THIS LOW STRENGTHENING AS IT GAINS LATITUDE...MOVING FROM PADUCAH KY FRIDAY NIGHT TO NEAR PITTSBURGH PA SATURDAY MORNING. AS THE LOW PASSES NORTH OF OUR REGION...A COLD FRONT TRAILING SOUTH FROM THE LOW WILL MOVE EAST ACROSS KY/TN...CROSSING THE APPALACHIAN MOUNTAINS SATURDAY...AND THEN MOVE EAST AND OFF THE COAST SATURDAY NIGHT. WIDESPREAD RAIN IS EXPECTED TO ACCOMPANY THESE FEATURES WITH A GENERAL HALF INCH /0.50/ TO ONE INCH /1.00/ OF RAINFALL ACROSS THE CWA...THE HEAVIER AMOUNTS OCCURRING ACROSS THE NORTHWESTERN CWA...STATE IF WV...CLOSER TO THE SURFACE LOW. WARM SOUTHWEST WINDS AHEAD OF THE FRONT ARE EXPECTED TO DISPLACE THE COOL WEDGE EAST OF THE MOUNTAINS...BUT SIMILAR TO THE LAST EVENT...THIS COOL AIR WILL BE VERY STUBBORN TO DISPLACE RIGHT AGAINST THE LEE SLOPE OF THE BLUE RIDGE UNTIL THE FRONT IS RIGHT ON TOP OF THE FORECAST AREA. AS A RESULT...AREAS WEST OF THE BLUE RIDGE WILL WARM EARLY SATURDAY...FOLLOWED BY THE PIEDMONT...THESE AREAS TESTING 50 DEGREES EARLY. THE NARROW STRIP OF COUNTIES AGAINST THE EASTERN SLOPE OF THE BLUE RIDGE...MWK-MTV-LYH-CHO LINE...WILL MOST LIKELY HOLDING OFF UNTIL LATE SATURDAY AFTERNOON B4 MIXING. PASSAGE OF THE FRONT WILL OF COURSE BEGIN ANOTHER COOL DOWN PROCESS...COLD AIR ADVECTION PUTTING A DRAG ON THE TEMPERATURE IN THE MOUNTAINS LATE SATURDAY AFTERNOON...FOLLOWED BY AN AREAWIDE COOL DOWN SATURDAY NIGHT...TEMPERATURES DIPPING BACK INTO THE 30S AS THE RAIN TAPERS FROM WEST TO EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 1230 PM EST WEDNESDAY... 12Z SUNDAY A SURFACE LOW IS WELL OFF THE COAST...MEANWHILE A SURFACE HIGH IS OVER SOUTHERN QUEBEC. THIS WILL ONCE AGAIN WEDGE THE AREA INTO A N/NE FLOW FOR SUNDAY AND MOST OF MONDAY. THE 12Z GFS IS MUCH DRIER THAN PREVIOUS RUNS BUT STILL LEFT LOW CHANCE POPS IN. MONDAY A LOW PRESSURE SYSTEM ACROSS WESTERN ONTARIO WILL DRIFT TOWARDS SOUTHERN QUEBEC THROUGHOUT THE DAY. A TRAILING COLD FRONT WILL SWING THROUGH OUR REGION MONDAY NIGHT AND INTO TUESDAY. THIS WILL INCREASE THE CHANCE OF SHOWERS ACROSS THE MOUNTAINS AND SOME SNOW SHOWERS AT THE HIGHER ELEVATIONS. FLOW BECOMES NORTHWEST AFTER THE FRONTAL PASSAGE AND HIGH PRESSURE STARTS TO BUILD IN FOR THE REMAINDER OF THE WEEK. LEFT LOW CHANCE POPS IN ACROSS THE FAVORED UPSLOPE REGIONS...HOWEVER MOISTURE LOOKS LIMITED AS OF THE LATEST GFS RUN. TEMPS DURING THE PERIOD WILL RUN A FEW DEGREES BELOW NORMAL...MAINLY LOOKING AT LOW TO MID 40S ACROSS THE MOUNTAINS AND NEAR 50 ACROSS THE PIEDMONT. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 1230 PM EST THURSDAY... CIGS WILL BE LOWERING FASTER THAN EARLIER THOUGH DESPITE THE DRIER AIRMASS IN THE EAST. WILL SEE RAIN WITH MVFR CIGS IN THE MTNS TO VFR EAST. RAIN WILL REACH ROA/BCB BY 18-20Z...AND LYH BY 21Z. DANVILLE WILL BE ON THE EDGE OF RAINFALL AND LOWER CIGS...BUT LOOKS LIKE MVFR CIGS WILL BE ATTAINED BY DUSK TODAY...AROUND 3KFT. THE WORST FLYING WX THROUGH TONIGHT WILL BE IN THE NRN FORECAST AREA FROM LYH TO LWB/BLF. THINK CIGS WILL TANK BELOW 1KFT BY EARLY EVENING IN THE MTNS...AND ROANOKE BY 03Z...LYH BY 08Z. THE PRECIPITATION WILL BE MAINLY -RA TO MODERATE RAIN. SOME PL OR FZRA NOT OUT OF THE QUESTION AT LWB...BUT OVERALL MODEL SHOWING THIS THREAT FURTHER NORTH TOWARD HSP TO EKN. VSBYS WILL STAY IN THE IFR/MVFR RANGE OVERALL. THESE CONDITIONS WILL SLOWLY IMPROVE TO MVFR LATE IN THE PERIOD EXCEPT LWB WHERE THINK IT STAY IFR INTO FRI AFTERNOON. EXTENDED DISCUSSION... HIGH PRESSURE WEDGE WILL PERSIST FRIDAY AFTERNOON INTO SATURDAY... WITH LINGERING MVFR CEILINGS MOST SPOTS AS WELL AS SPOTTY -RA OR -DZ ESPECIALLY THE MOUNTAINS INTO SATURDAY MORNING. LOW PRESSURE FORECAST TO TRACK ACROSS THE CENTRAL APPALACHIANS TO VA COAST BY SAT EVENING WILL CLEAR THE WEDGE OUT BUT EXPECT SUB VFR CIGS AND AT TIME VSBYS WITH RAIN TO STAY AROUND SATURDAY...ENDING BY SAT NIGHT. AIRMASS DRIES OUT SUNDAY AS HIGH PRESSURE MOVES BACK IN FROM THE NORTH. THIS HIGH WILL SET UP ANOTHER WEDGE BY MONDAY BUT NO PRECIP IS EXPECTED UNTIL MON NIGHT-TUESDAY WHEN CIGS/VSBYS WILL FALL UNDER VFR AGAIN. && .EQUIPMENT... AS OF 500 AM EST THURSDAY... VISIBILITY SENSOR AT KLYH...LYNCHBURG AIRPORT...IS WORKING IN A DEGRADED MODE. PARTS WILL BE IN BY EARLY NEXT WEEK...THEN REPAIRS CAN BE COMPLETED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...NF/WP NEAR TERM...NF/WP SHORT TERM...PM LONG TERM...CF AVIATION...NF/WP EQUIPMENT...AMS/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1010 AM EST THU DEC 4 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD SOUTHWARD ACROSS THE PIEDMONT TO WEDGE AGAINST THE EASTERN FACE OF THE APPALACHIANS...BRINGING COLDER AIR INTO THE REGION THIS AFTERNOON. A SERIES OF UPPER LEVEL DISTURBANCES WILL PASS ACROSS THE REGION THIS EVENING AND TONIGHT...BRINGING RAIN FOR MOST LOCATIONS...AND POCKETS OF FREEZING RAIN TO THE HIGHER RIDGES ALONG THE INTERSTATE 64 CORRIDOR...SOUTH ALONG THE BLUE RIDGE PARKWAY. A DEEP LOW PRESSURE SYSTEM WILL PASS ACROSS THE AREA SATURDAY...BRINGING WIDESPREAD RAIN. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1005 AM EST THURSDAY... HAVE UPDATED FORECAST TO SPEED UP TIMING OF RAIN IN THE MOUNTAIN EMPIRE. THE 13Z HRRR WAS HANDLING THE SPOTTY RAIN ON RADAR IN FAR SW VA/SE KY THIS MORNING AND EXPECT SLIGHT TO LOW CHANCE POPS IN THE FAR WEST BY MIDDAY WITH RAIN REACHING THE NEW RIVER VALLEY BY 1 TO 3 PM. MAINLY IT WILL BE LIGHT IN INTENSITY. 12Z RNK SOUNDING VERY DRY THIS MORNING WITH THIS BATCH OF RAIN HELPING TO LOWER THE CLOUD DECK BY LATE IN THE DAY. REST OF THE FORECAST THROUGH THIS AFTERNOON LOOKS ON TRACK FROM EARLIER FORECAST. PREVIOUS VALID DISCUSSION... INCREASING CLOUDS AND WEDGING TODAY WILL LIMIT HEATING...AND HAVE UNDERCUT MODEL GUIDANCE BY 2 TO 4 DEGREES FOR AFTERNOON TEMPERATURES...WITH HIGHS HOLDING IN THE LOW 50S ACROSS THE NORTH CAROLINA PIEDMONT...AND IN THE 40S FURTHER NORTH. POCKETS OF MIXED PRECIPITATION STILL APPEAR LIKELY BEGINNING AS EARLY AS 8 PM THIS EVENING IN THE VICINITY OF THE INTERSTATE 64 CORRIDOR. THE HIGH PRESSURE WEDGE WILL CONTINUE TO STRENGTHEN THROUGH THE NIGHT...FORCING INCREASINGLY COLDER AIR INTO OUR AREA FOR THE RAIN TO FALL INTO. WHILE TEMPERATURES WILL REMAIN WARM ENOUGH MOST LOCATIONS THAT PRECIPITATION WILL REMAIN LIQUID...SOME OF THE RIDGELINES WILL BE TRAPPED IN THE SUB-FREEZING AIR THAT MOVES IN LATE TONIGHT. IN THESE LOCATIONS...WILL START OFF WITH A FEW AREAS OF SLEET...WHICH WILL TRANSITION TO LIGHT FREEZING RAIN TOWARD DAWN ON FRIDAY. ICING ACCUMULATIONS ARE EXPECTED TO BE LIGHT AND SPOTTY...GENERALLY LESS THAN A TENTH OF AN INCH...AND MAINLY ON ELEVATED OBJECTS...ALTHOUGH ROADS MAY BECOME SLICK IN A FEW SPOTS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EST THURSDAY... COLD AIR WILL BE DAMMED AGAINST THE EASTERN SLOPES OF THE APPALACHIANS FRIDAY PER 1040 MB SURFACE HIGH OVER NEW ENGLAND. THIS AIRMASS WILL BE HARD TO DISPLACE...LEAVING US WITH A COOL CLOUDY DAY REINFORCED BY AN EAST OR NORTHEAST WIND. ABOVE THE WEDGE OF COOL AIR...WINDS WILL BE OUT OF THE SOUTHWEST...WARM/MOIST AIR BEING DRAWN NORTHEAST FROM THE GULF OF MEXICO. 850 TEMPS ARE PROGGED TO BE IN THE +6 TO +8 DEG C RANGE...SO HYDROMETEORS SHOULD FALL AS LIQUID. ANY P-TYPE ISSUES WILL BE EARLY FRIDAY MORNING PER SURFACE TEMPERATURES NEAR 32 DEGREES IN THE NORTHEASTERN CWA...VA/WV HIGHLANDS AND THE BLUE RIDGE PARKWAY NORTHEAST OF ROANOKE...WITH POCKETS OF FREEZING RAIN RESULTING IN SOME LIGHT ICE ACCRETIONS MAINLY IN THE TREES AND ON ELEVATED SURFACES. ASIDE FROM THIS PTYPE ISSUE IN THE MORNING...NO SIGNIFICANT CONCERNS NOTED FOR THE AFTERNOON WITH JUST A CONTINUED THREAT FOR LIGHT RAIN OR DRIZZLE. MODEL TEMPERATURE GUIDANCE HAS FINALLY COME AROUND TO RECOGNIZING THE COLD WEDGE FRIDAY...KEEPING ALL AREAS...WITH THE EXCEPTION OF AREAS WEST OF THE APPALACHIAN DIVIDE...ANCHORED IN THE 30S/40S THROUGHOUT THE DAY. WEDGE IS EXPECTED TO HOLD THROUGH FRIDAY NIGHT WITH COOL BUT STEADY TEMPERATURES. WENT WITH THE COOLER MET/NAM GUIDANCE...HOLDING OFF ON ANY MIX DOWN OF WARM AIR ALOFT UNTIL SATURDAY. FORECAST MODELS ARE GENERALLY TOO AGGRESSIVE MIXING OUT THE COOL WEDGE...AND GIVEN THE STRENGTH OF THE SFC HIGH OVER NEW ENGLAND SEE NO REASON TO DEVIATE. OTHER THAN SOME WEAK ISENTROPIC LIFT FRIDAY AFTERNOON AND FRIDAY NIGHT...ANY PRECIP SHOULD BE LIGHT...IN THE FORM OF LIGHT RAIN OR DRIZZLE...QPF LESS THAN A QUARTER OF AN INCH FRIDAY/FRIDAY NIGHT. BY SATURDAY...DYNAMIC LIFT WILL INCREASE YIELDING HIGHER PRECIPITATION RATES PER DEVELOPMENT AND PROGRESSION OF LOW PRESSURE WHICH WILL PASS OVER/NEAR THE AREA. MODELS ARE IN GENERAL AGREEMENT THAT SHORT WAVE ENERGY EXITING THE SOUTHWEST CONUS COURTESY OF AN ACTIVE SOUTHERN JET STREAM WILL RESULT IN THE DEVELOPMENT OF LOW PRESSURE OVER THE MID MS VALLEY FRIDAY NIGHT...THIS LOW STRENGTHENING AS IT GAINS LATITUDE...MOVING FROM PADUCAH KY FRIDAY NIGHT TO NEAR PITTSBURGH PA SATURDAY MORNING. AS THE LOW PASSES NORTH OF OUR REGION...A COLD FRONT TRAILING SOUTH FROM THE LOW WILL MOVE EAST ACROSS KY/TN...CROSSING THE APPALACHIAN MOUNTAINS SATURDAY...AND THEN MOVE EAST AND OFF THE COAST SATURDAY NIGHT. WIDESPREAD RAIN IS EXPECTED TO ACCOMPANY THESE FEATURES WITH A GENERAL HALF INCH /0.50/ TO ONE INCH /1.00/ OF RAINFALL ACROSS THE CWA...THE HEAVIER AMOUNTS OCCURRING ACROSS THE NORTHWESTERN CWA...STATE IF WV...CLOSER TO THE SURFACE LOW. WARM SOUTHWEST WINDS AHEAD OF THE FRONT ARE EXPECTED TO DISPLACE THE COOL WEDGE EAST OF THE MOUNTAINS...BUT SIMILAR TO THE LAST EVENT...THIS COOL AIR WILL BE VERY STUBBORN TO DISPLACE RIGHT AGAINST THE LEE SLOPE OF THE BLUE RIDGE UNTIL THE FRONT IS RIGHT ON TOP OF THE FORECAST AREA. AS A RESULT...AREAS WEST OF THE BLUE RIDGE WILL WARM EARLY SATURDAY...FOLLOWED BY THE PIEDMONT...THESE AREAS TESTING 50 DEGREES EARLY. THE NARROW STRIP OF COUNTIES AGAINST THE EASTERN SLOPE OF THE BLUE RIDGE...MWK-MTV-LYH-CHO LINE...WILL MOST LIKELY HOLDING OFF UNTIL LATE SATURDAY AFTERNOON B4 MIXING. PASSAGE OF THE FRONT WILL OF COURSE BEGIN ANOTHER COOL DOWN PROCESS...COLD AIR ADVECTION PUTTING A DRAG ON THE TEMPERATURE IN THE MOUNTAINS LATE SATURDAY AFTERNOON...FOLLOWED BY AN AREAWIDE COOL DOWN SATURDAY NIGHT...TEMPERATURES DIPPING BACK INTO THE 30S AS THE RAIN TAPERS FROM WEST TO EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 1230 PM EST WEDNESDAY... 12Z SUNDAY A SURFACE LOW IS WELL OFF THE COAST...MEANWHILE A SURFACE HIGH IS OVER SOUTHERN QUEBEC. THIS WILL ONCE AGAIN WEDGE THE AREA INTO A N/NE FLOW FOR SUNDAY AND MOST OF MONDAY. THE 12Z GFS IS MUCH DRIER THAN PREVIOUS RUNS BUT STILL LEFT LOW CHANCE POPS IN. MONDAY A LOW PRESSURE SYSTEM ACROSS WESTERN ONTARIO WILL DRIFT TOWARDS SOUTHERN QUEBEC THROUGHOUT THE DAY. A TRAILING COLD FRONT WILL SWING THROUGH OUR REGION MONDAY NIGHT AND INTO TUESDAY. THIS WILL INCREASE THE CHANCE OF SHOWERS ACROSS THE MOUNTAINS AND SOME SNOW SHOWERS AT THE HIGHER ELEVATIONS. FLOW BECOMES NORTHWEST AFTER THE FRONTAL PASSAGE AND HIGH PRESSURE STARTS TO BUILD IN FOR THE REMAINDER OF THE WEEK. LEFT LOW CHANCE POPS IN ACROSS THE FAVORED UPSLOPE REGIONS...HOWEVER MOISTURE LOOKS LIMITED AS OF THE LATEST GFS RUN. TEMPS DURING THE PERIOD WILL RUN A FEW DEGREES BELOW NORMAL...MAINLY LOOKING AT LOW TO MID 40S ACROSS THE MOUNTAINS AND NEAR 50 ACROSS THE PIEDMONT. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... AS OF 730 AM EST THURSDAY... HIGH PRESSURE CONTINUES TO WEDGE AGAINST THE EASTERN FACE OF THE APPALACHIANS THIS MORNING...SHIFTING WINDS INCREASINGLY NORTHEASTERLY AS IT BUILDS ALONG THE BLUE RIDGE. STARTING THE MORNING OFF VFR MOST LOCATIONS...WITH POCKETS OF FOG ACROSS THE MOUNTAINS. FOG IS EXPECTED TO BURN OF WITH DAYTIME HEATING AFTER 14Z. OUTSIDE OF FOG...EXPECT VFR CONDITIONS THROUGH THE AFTERNOON. RAIN CHANCES WILL INCREASE SIGNIFICANTLY BEGINNING 18Z FOR MOST AIRPORTS AS AN UPPER LEVEL DISTURBANCE PASSING ACROSS KENTUCKY AND TENNESSEE PUSHES ACROSS THE MOUNTAINS LATER IN THE DAY. THIS RAIN WILL MOISTEN THE ATMOSPHERE...BRINGING IT TO SATURATION DURING THE EVENING... WHICH WILL CAUSE CEILINGS TO LOWER TO LOW MVFR/IFR LEVELS AFTER SUNSET...WITH LITTLE TO NO IMPROVEMENT EXPECTED THROUGH THE NIGHT. IN ADDITION TO LOW CEILINGS...PATCHY FOG AND DRIZZLE WILL DEVELOP... ALSO HOLDING VISIBILITIES DOWN. THE HIGH PRESSURE WEDGE WILL CONTINUE TO STRENGTHEN THROUGH THE NIGHT...BRINGING INCREASINGLY COLDER AIR INTO THE AREA. AS SUCH... POCKETS OF SLEET AND FREEZING RAIN ARE EXPECTED TO DEVELOP LATE THURSDAY NIGHT INTO FRIDAY MORNING...MAINLY FOR THE RIDGES ALONG THE INTERSTATE 64 CORRIDOR...AND SOUTHWARD ALONG THE SPINE OF THE BLUE RIDGE. NO TAF SITES ARE EXPECTED TO EXPERIENCE ANYTHING BUT LIQUID PRECIPITATION. TEMPERATURES WILL WARM ENOUGH BY LATE FRIDAY MORNING TO END FREEZING PRECIPITATION. EXTENDED DISCUSSION... HIGH PRESSURE WEDGE WILL PERSIST FRIDAY AFTERNOON INTO SATURDAY... WITH LINGERING MVFR CEILINGS MOST SPOTS AS WELL AS SPOTTY -RA OR -DZ ESPECIALLY THE MOUNTAINS INTO SATURDAY MORNING. LOW PRESSURE THAT IS FORECAST TO SLIDE UP ALONG THE WESTERN SIDE OF THE APPALACHIANS MAY ACT TO HELP SCOUR OUT THE WEDGE BY SATURDAY NIGHT AS THE ASSOCIATED COLD FRONT PUSHES ACROSS. HOWEVER RAIN AND LOW CEILINGS PRECEDING THIS SYSTEM LIKELY TO MAKE FOR PERIODS OF IFR ESPECIALLY SATURDAY AFTERNOON AND EVENING. DRIER AIR BEHIND THE FRONT MAY BRING A BRIEF RETURN OF VFR ON SUNDAY BUT LOW CONFIDENCE GIVEN THE SLOWNESS OF THIS SYSTEM TO MOVE OFFSHORE. OTHERWISE...YET ANOTHER WEDGE INCLUDING SUB-VFR CEILINGS TO REDEVELOP SUNDAY NIGHT INTO MONDAY IN THE WAKE OF THE DEPARTING FRONT. && .EQUIPMENT... AS OF 500 AM EST THURSDAY... VISIBILITY SENSOR AT KLYH...LYNCHBURG AIRPORT...IS WORKING IN A DEGRADED MODE. PARTS WILL BE IN BY EARLY NEXT WEEK...THEN REPAIRS CAN BE COMPLETED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...NF NEAR TERM...NF/WP SHORT TERM...PM LONG TERM...CF AVIATION...AMS/JH/NF/WP EQUIPMENT...AMS/WP Area Forecast Discussion National Weather Service Spokane WA 710 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Evening update: the forecast is generally on track, with newest models continuing to bring the next batch of precipitation in from the west tonight into Saturday. The chances tonight will be largely near the Cascades, with the highest threat starting after about 09Z (1 AM). Some light precipitation will also be possible across the northern mountains of WA and ID tonight. Models then blossom the precipitation across the remainder of eastern WA and north ID between 4 AM and 1 PM Saturday, before things start to wind down from the west Saturday night. Some adjustments made to increase fog coverage from the previous forecast, though it is expected to be largely patchy in fashion and may still have opportunity to decrease from the southeast overnight. Main area I added some patchy fog was toward the Blues and L-C Valley, as well as out across the Basin into the the Waterville Plateau. The fog is down to a half mile or so in spots, such as near GEG and LWS, though it hasn`t been all that consistently that low in LWS. I kept the fog going through the night, but make it patchier in areas where it has been most dense (i.e. western Spokane county and along the highway 2 corridor. Later in the forecast, toward Saturday night into Sunday morning, models suggest some low level moisture and southwest flow will combine to bring a stratus and fog threat. It seems like a good pattern for it. So the forecast was update to add this for a good chunk of the basin/valley areas. Its coverage will be fine tuned over the next day or so. /J. Cote` && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 38 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 38 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 43 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 46 / 10 90 10 0 10 20 Colville 32 34 31 38 29 38 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 37 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 38 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$
Area Forecast Discussion National Weather Service Spokane WA 710 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Evening update: the forecast is generally on track, with newest models continuing to bring the next batch of precipitation in from the west tonight into Saturday. The chances tonight will be largely near the Cascades, with the highest threat starting after about 09Z (1 AM). Some light precipitation will also be possible across the northern mountains of WA and ID tonight. Models then blossom the precipitation across the remainder of eastern WA and north ID between 4 AM and 1 PM Saturday, before things start to wind down from the west Saturday night. Some adjustments made to increase fog coverage from the previous forecast, though it is expected to be largely patchy in fashion and may still have opportunity to decrease from the southeast overnight. Main area I added some patchy fog was toward the Blues and L-C Valley, as well as out across the Basin into the the Waterville Plateau. The fog is down to a half mile or so in spots, such as near GEG and LWS, though it hasn`t been all that consistently that low in LWS. I kept the fog going through the night, but make it patchier in areas where it has been most dense (i.e. western Spokane county and along the highway 2 corridor. Later in the forecast, toward Saturday night into Sunday morning, models suggest some low level moisture and southwest flow will combine to bring a stratus and fog threat. It seems like a good pattern for it. So the forecast was update to add this for a good chunk of the basin/valley areas. Its coverage will be fine tuned over the next day or so. /J. Cote` && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 38 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 38 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 43 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 46 / 10 90 10 0 10 20 Colville 32 34 31 38 29 38 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 37 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 38 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$
Area Forecast Discussion National Weather Service Spokane WA 405 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Tonight: Conditions will dry out across the eastern and southern third of the forecast area while the Cascades...Wenatchee Area...and areas of the northern mountain deal with a messy wintry mix. Precipitation for much of today has been uneventful to say the least with most midlevel circulations falling apart once they cross into Chelan County. Regional radar indicates a line of showers continuing to fill in from Kittitas County southward to the central Oregon Cascades which are tracking north toward the Hwy 97 corridor. It is uncertain whether these showers will survive the trip into Chelan/Douglas Counties but HRRR continues to hint at some showers during the 23-02z time-frame. Most locations remain below freezing with a few exceptions. With wetbulb effects and sunset approaching, it is unlikely any location will remain above freezing. The showers moving through the next few hours will not be a major player for freezing rain. Freezing rain advisories were extended to capture steady light to moderate precipitation moving in after midnight and continuing into Saturday morning. This is a much different setup compared the last 48 hours which have proved much drier than expected. This system will feature southeast flow in the lower levels, moderate isentropic ascent, and rich moisture. So as far as I am concerned, the precipitation will be certain...now the temperatures will be a bigger wild card. Temperatures are typically slow to warm with SE flow in the lower levels however as the air mass moistens...it has no where to go but warmer. When this transition occurs will be the challenge of the night. Needless to say, travel is likely to be slick near the Cascades and Wenatchee Area. Some light precip is possible in the Okanogan Valley and Northern Mountains but amounts should be low and concerns are lower. One other travel concern looks to be localized along Hwy 2 between Airway Heights and Davenport which is dense fog. There may be a few other areas out there, but this looks to be the worse case via a tour of CAMS and motorists should plan on visibilities near 1/4 mile at times. Temperatures remain near 32F for most locations north of I-90 so there is also the potential for black ice redeveloping tonight. Temperatures will not fall much from current readings (maybe 1-2 degrees) and may even rise or remain steady for much of the night so we are not expecting a hard freeze in any locations. /sb Saturday through Monday...High pressure will be over the Pacific Northwest through Sunday before getting pushed off to the east Sunday night. A couple of vigorous but fast moving short wave disturbances will move through the ridge...the first on Saturday...the second on Monday. These two waves will result in more wet weather across the region through the short term. Temperatures will be on the increase with warm air advection and should be above normal through Monday. *Precipitation: Yes more wet weather with chances of mixed precipitation. The wave moving through the region on Saturday will tap into fairly deep Pacific moisture and combine with moderate to strong isentropic up-glide and orographic lift for light to moderate precipitation. Precipitation will be on the increase across the western zones around 12z and push across the forecast area through the day. A cold front will follow quickly behind. The front should eject into Montana late Saturday afternoon. Low level southeast-south flow Saturday morning will eliminate any Cascade shadowing for the lowers east slopes and the deep basin. The flow will shift around to the southwest-west by late Saturday afternoon as the front moves through the area. Drying from the west should begin by late morning, with precipitation lingering across the Panhandle through the evening hours. Saturday night and Sunday the area will be in a dry period, although fog and low clouds will be probable. The next weak wave will run through the ridge on Monday. This wave does not have the deep moisture tap nor the lifting mechanism of the previous wave but will still result in some very light precipitation Monday afternoon. *Precipitation type: The valleys up against the Cascades have had difficulty mixing out the cold air damned up against the mountains. All indications are that precipitation may be as freezing rain overnight, but should turn over to snow before sunrise Saturday...especially for the Methow valley. Along the the Columbia river and some of the northern valleys freezing rain may also be a possibility for a few hours early Saturday morning, but with increasing southerly flow these valleys should switch over to rain. Precipitation amounts will range from around a tenth or more for the lower elevations and a quarter to a third of an inch for the mountains for the Saturday system. Snow accumulation of 3-4 inches will be possible for the mountains with possibly 1-2 inches for the Methow valley. For the Monday system precipitation should be as valley rain and mountain snow, with very light accumulations. Tobin Monday night through Friday: Confidence is high that the region will see a pattern shift through next week. Medium range models are in good agreement that the longwave ridge of high pressure will shift east into the Rookies and over the Northern Plains. This will place the region in a more mild and wet weather pattern. A pair of very moist low pressure systems will impact the region. There is still some uncertainty with the timing of these two systems. There is better agreement with the first system as models show the region firmly under the warm sector Monday night into Tuesday, and then the cold front sweeping through around Tuesday afternoon or night. Models diverge considerably more with the second weather system. The ECMWF is faster and shows a stronger warm frontal passage Tuesday night into Wednesday morning. The GFS is much slower with precip redeveloping Wednesday afternoon/evening. Snow levels will be increasing with each of these weather systems. A pocket of cold air looks to remain along the lee side of the northern Cascades into the Okanogan Highlands through at least Monday night. This will keep snow levels lower to between 2,000 and 3,000 feet. There is a chance for some wet snow in the upper reaches of the Methow Valley, but confidence is low. All other valley locations are expected to see rainfall. Moderate to heavy rainfall amounts will be possible with P-wats +2 standard deviations of normal and up to between 0.75-1.00 inches. Temperatures will warm to above normal through mid week. The upper level trough in the Gulf of Alaska looks to dig in across the region late next week. This will result in an end to the warming trend with temperatures dipping back closer to normal by Friday. /SVH && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 39 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 39 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 44 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 47 / 10 90 10 0 10 20 Colville 32 34 31 38 29 39 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 38 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 39 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML

Area Forecast Discussion National Weather Service Spokane WA 306 AM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Today and tonight ... The widespread precipitation from earlier tonight is beginning to taper off as the shortwave disturbance which enhanced the ascent and moisture continues to push toward Montana. The latest radar imagery was only detecting a smattering of light precipitation generally east of a line from Kettle Falls to the Camas Prairie. The trend for this precipitation will be a diminishing one as drier air begins to infiltrate the key dendritic layer. Whether or not this truly eliminates the precipitation is questionable as the layer beneath will continue to see fair isentropic ascent combined with a fairly moist lowest level of the atmosphere. This could either equate to very light snow or freezing drizzle. For the Spokane and Coeur d`Alene area we could see a little of both. Precipitation alone will not necessitate the extension of the freezing rain advisory however with temperatures hovering right at or slightly below freezing road conditions will likely remain poor until later today. North and east of the Spokane area we suspect most of the precipitation will remain as light snow at least until sunrise. After that it could also become a combination of very light snow or freezing drizzle as the dendritic layer dries here as well. Elsewhere the current weather regime is fairly quiet...however that will likely change as a warm front moves in from the southwest. Regional radar mosaics show precipitation from this front blossoming along a line from the Dalles toward Olympia moving northeastward. How far east the precipitation from this feature spreads is the big question for today. Model guidance is in decent agreement that most of it will remain confined to the west of Moses Lake toward the Cascades. The HRRR model says not much will result from the approach of the front this morning...however it`s under-doing the amount of precipitation falling right now near the Columbia Gorge. Most of the remaining model guidance suggests precipitation will likely fall in these areas but amounts should be well under a tenth of an inch. Based on temperature profiles in that area...the main precipitation regime will likely be freezing rain with snow generally north of Lake Chelan. Given this scenario...we will continue with the various freezing rain advisories for now as confidence is high as ground temperatures will remain below freezing with a melting layer between 2-4k feet above ground. For later today and into the evening...the front continues to move to the north while the mean mid-level flow turns increasingly southerly. This will allow the surface warm sector to surge northward bringing a brief drying trend beginning over SE Washington/NC Idaho and moving northward. During this time most of the precipitation will remain confined near the Cascades as well as the far northern portions of the forecast area. Most of the precipitation will transition from snow to rain in the northern valleys...however sub-freezing air will remain fixed near the Cascades...so freezing rain or snow will remain the most common precipitation type. The precipitation threat will likely increase once again late tonight...at least near the Cascades. This time the precipitation will result from the approach of a shortwave trough currently near 132w. By this time it arrives the only locations left with an elevated melting layer and sub- freezing air near the ground will be near the Cascades. This is actually the strongest of the systems expected during the next 24 hours. Precipitation chances will be nearly 100 percent near the Cascades as the mid-layer flow backs to more of a southeast regime resulting in good upslope flow potential. While pockets of freezing rain will still be possible...it will be far from as widespread as the threat this morning will be. No highlights are anticipated for tonight`s event. Valleys which see snow could pick up 1-2 inches...especially north of Lake Chelan...with mountain snows of several inches possible. Precipitation will really begin to pick up by Saturday morning. fx Saturday through Sunday Night: An upper level trough will move through the area in southwest flow Saturday. Models have been pretty consistent and so confidence is high of widespread rain. Cold air will still remain across the Methow valley and nearby valleys. Expect a mixed bag of snow and freezing rain through at least the morning hours. By afternoon the winds become more westerly and our typical shadowing of the east slopes valleys and into the Moses Lake area will occur. Precip will decrease from west to east through the day. By Sat evening most of the rain and mountain snow will be confined to north ID. Sunday is the only dry period in the entire 7 day forecast...so enjoy it while you can. Models have been slowing down the next oncoming weather system, and so have decreased chance of precipitation quite a bit for Sunday night. The best chance of precip will be along the Cascades. Monday through Wednesday: Large amounts of moisture will stream in from the Pacific to create quite a wet period. Broad southwest flow will usher in wave after wave. The first widespread precip event starts Monday night into Tuesday. The southwest flow will provide warmer air and temperatures should remain above freezing south of Highway 2 for a rain event. The northern valleys across northeast WA and north ID will see rain...however the valleys across north central WA will see a rain/snow mix or rain during the day with snow at night. The mountains will see mostly snow. Snow levels will vary...but generally 3500-4000 feet is expected across northern WA and ID. Still concerned about the potential of feet of snow in the Cascades Monday night through Tuesday night. The GFS is going gangbusters with qpf, where as the EC is being more conservative. Either model you go with...we are still talking at least 2 feet of snow possible along the crest. Confidence is also growing for heavy snow potential in the Northeast Mountains of WA and the North ID Panhandle Mountains for Tuesday. Main changes made to this portion of the forecast was to decrease chances of precip Monday. Models seem to be slowing down the timing of the onslot of moisture. Thursday and Friday: The models really start to diverge by late in the work week. The EC and GFS both have a longwave trough over the western US, but they vary greatly on locations of where low pressure systems will set up. Either way the result is still south to southwest flow with periods of rain and snow in the forecast. Temperatures: Temperatures Saturday through next Friday will be above average. Models have backed off a bit on how warm we could get Sat through Mon, so have started the trend down a bit, but will still see above average temps. Highs in the mid 30s to mid 40s with lows in the mid 20s to mid 30s are expected across the Inland Northwest. /Nisbet && .AVIATION... 06Z TAFS: Wintry mix continues across eastern WA and north ID. GEG to COE are expected to see -fzra through the early overnight, with chances waning between 09-12Z. That may change to rain near SFF during the time. Look for IFR cigs and vis, with potentialy dense fog near GEG for the early morning 14-19Z or so. Conditions will remain IFR and low MVFR in that region after 19Z. Toward PUW/LWS mainly rain is expected tonight, with a similar decrease in the precipitation threat going into Friday morning. IFR/MVFR conditions expected here, with possible VFR conditions around LWS in the afternoon. Farther west toward MWH and especially EAT the threat of freezing rain will develop overnight into Friday morning, with the front slipping into region. So look for some icing threat around especially around 11-18Z in EAT, with a smaller risk in MWH. /J. Cote` && .PRELIMINARY POINT TEMPS/POPS... Spokane 35 33 39 32 39 31 / 40 10 90 10 0 0 Coeur d`Alene 35 33 38 33 40 31 / 40 10 90 20 0 0 Pullman 40 35 41 33 42 35 / 20 10 90 10 0 0 Lewiston 42 37 44 35 45 37 / 20 10 80 0 0 0 Colville 35 31 38 31 39 30 / 80 30 70 20 0 10 Sandpoint 34 32 38 32 39 30 / 70 20 90 40 10 0 Kellogg 36 32 37 33 40 31 / 50 10 100 40 0 0 Moses Lake 35 31 40 30 40 31 / 50 40 80 0 0 10 Wenatchee 34 31 39 30 37 32 / 60 60 70 0 0 10 Omak 32 30 36 27 35 29 / 90 60 70 0 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Freezing Rain Advisory until 4 AM PST early this morning for Coeur d`Alene Area-Idaho Palouse. WA...Air Stagnation Advisory until 4 AM PST Saturday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until 10 AM PST this morning for East Slopes Northern Cascades-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until 4 AM PST early this morning for Spokane Area-Washington Palouse. Freezing Rain Advisory until 7 AM PST this morning for Moses Lake Area-Upper Columbia Basin. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
307 PM CST THU DEC 4 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 307 PM CST THU DEC 4 2014 AT 2 PM...A 1031 MB SURFACE HIGH WAS CENTERED OVER SAGINAW BAY /PART OF LAKE HURON/. SOUTHERLY WINDS ON THE BACK SIDE OF THIS HIGH HAVE CAUSED TEMPERATURES SOUTH OF INTERSTATE 94 TO CLIMB INTO THE LOWER AND MID 30S. MEANWHILE NORTH OF THIS INTERSTATE...THE TEMPERATURES ARE STILL IN THE 20S. FOR TONIGHT AND FRIDAY MORNING...THE 04.12Z MODELS ARE IN GOOD AGREEMENT THAT WEAK 925 TO 850 MB MOISTURE TRANSPORT WILL DEVELOP ACROSS THE AREA. THIS IS IN ADVANCE OF A SHORT WAVE TROUGH WHICH WILL BE MOVING EAST ACROSS NORTHERN MINNESOTA AND NORTHERN WISCONSIN. THE NAM AND RAP SOUNDINGS SHOW THAT THE AIR MASS BELOW 800 MB WILL BECOME SATURATED AND THERE WILL BE SOME WEAK OMEGA IN THIS LAYER. THIS WOULD RESULT IN PATCHY FREEZING DRIZZLE. MEANWHILE THE GFS...SATURATES THE LAYER BETWEEN 950 AND 800 MB AND KEEPS A DRY LAYER NEAR THE SURFACE. THIS WOULD RESULT IN JUST A LIFR/IFR DECK OF CLOUDS. UNTIL THIS PAST HOUR WAS LEANING MORE TOWARD THE GFS BECAUSE THERE WAS NO DRIZZLE OR LOW CLOUDS ACROSS NORTHERN MISSOURI AND CENTRAL ILLINOIS. HOWEVER BOTH OF THESE ARE STARTING TO SHOW UP IN THE OBSERVATIONS ACROSS THIS AREA...SO MAYBE THE NAM AND RUC ARE HANDLING THIS BETTER THAN ORIGINALLY THOUGHT. DUE TO THIS...KEPT A 15 PERCENT PRECIPITATION CHANCE FOR FREEZING DRIZZLE IN THE FORECAST. LIKE THE PREVIOUS SHIFT...USED THE 925 TO 850 MB RELATIVE HUMIDITY TO TIME THE FREEZING DRIZZLE ONSET AND ENDING. ON FRIDAY AFTERNOON AND EVENING...A SHORT WAVE TROUGH IN THE SOUTHERN STREAM WILL MOVE NORTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY INTO THE SOUTHERN GREAT LAKES. LIKE PREVIOUS RUNS...IT LOOKS LIKE THE SYNOPTIC LIFT AND MOISTURE WILL REMAIN SOUTHEAST OF THE FORECAST AREA. AS A RESULT...KEPT THE FORECAST DRY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 307 PM CST THU DEC 4 2014 FROM SUNDAY THROUGH MONDAY...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH WILL MOVE EAST THROUGH THE REGION. THIS WAVE REMAINS AN OPEN WAVE SO THE MODELS ARE MORE PROGRESSIVE THAN THEY WERE EARLIER. DUE TO THIS...IT LOOKS LIKE THE PRECIPITATION WILL LIKELY ONLY OCCUR FOR AN 12 TO 18 HOUR PERIOD. SOME OF THE MODELS SUGGEST THAT DRY AIR WILL MOVE IN ALOFT ON SUNDAY NIGHT. IF THIS IS CORRECT...THERE WOULD BE A LOSS OF ICE FROM ALOFT...AND THE PRECIPITATION TYPE WOULD CHANGE FROM SNOW TO EITHER A RAIN OR FREEZING RAIN. SOME OF THE MODELS SUGGEST THAT THE TEMPERATURES WILL REMAIN ABOVE FREEZING ACROSS MUCH OF THE AREA...SO MAY NOT HAVE TOO MUCH OF A FREEZING RAIN THREAT. SINCE THIS IS STILL OVER 84 HOUR OUT...IT WAS THE CONSENSUS TO JUST KEEP THE FORECAST IN THE FORM OF RAIN AND SNOW FOR NOW. WITH THE MIXED PRECIPITATION AMOUNTS...DOES NOT LOOK LIKE THERE WILL BE TOO MUCH SNOW. GFS COBB DATA CURRENTLY IS SHOWING A HALF INCH OR LESS OF SNOW. ON WEDNESDAY...THE GFS SHOW THAT A SHORT WAVE TROUGH WILL PRODUCE RAIN OR FREEZING RAIN AS IT MOVES THROUGH THE NORTHERN MINNESOTA AND WISCONSIN. SOUNDINGS NORTH OF INTERSTATE 94 KEEP MUCH OF THEIR SATURATION BELOW 900 MB AND BETWEEN 600 AND 700 MB...SO THINKING THAT THE MODELS MAY BE OVER DOING THIS PRECIPITATION...SO OPTED TO FOLLOW THE ECMWF AND KEEP THE FORECAST DRY FOR NOW. ON THURSDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAST WE WILL WARM UP. THE GFS WARMS THE 850 MB TEMPERATURES INTO THE 10 TO 14C RANGE. MEANWHILE THE ECMWF HAS THESE TEMPERATURES RANGING FROM 0 TO -4C. THE CFS VERSION 2 OVER THE PAST 5 DAYS ARE SUGGESTING THAT THE HIGHS ON THIS DAY WILL RANGE FROM 35 TO 40 NORTH OF INTERSTATE 94 AND FROM 40 TO 45 WITH A STANDARD DEVIATION LESS THAN 1. MEANWHILE THE DETERMINISTIC ECMWF MOS HAS HIGHS AROUND 30...BUT THIS IS MUCH LOWER THAN ITS ENSEMBLE MEAN. WITH SUCH DIFFERENCES STAYED NEAR THE MODEL BLEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1131 AM CST THU DEC 4 2014 INITIAL CONCERN IS CLOUD TRENDS. MID-LEVEL CEILING IS TRAVERSING EAST...BUT NEXT ROUND OF WARM ADVECTION SENDING A NEW CLOUD SHIELD AT US FROM THE SOUTH. EXPECT THAT TO ARRIVE AT THE AIRFIELDS SHORTLY AFTER SUNSET. CEILINGS GRADUALY LOWER AS LOW LEVEL MOISTURE INCREASES AHEAD OF THE SHORT WAVE TROUGH MOVING THROUGH THE CENTRAL PART OF THE COUNTRY. BULK OF THE PRECIPITATION WILL STAY WELL SOUTH...BUT MODEL SOUNDINGS DO SUPPORT THE POSSIBILITY OF A SATURATED BOUNDARY LAYER UP TO ABOUT 4KFT. THIS WILL LEAD TO STRATUS AND PERHAPS SOME LIGHT FOG. DRIZZLE IS ALSO A DISTINCT POSSIBILITY AND WITH THE SOUNDING ALL BELOW FREEZING BUT NO SOURCE OF ICE...IF IT OCCURS WILL BE AS FREEZING DRIZZLE. THIS CHANCE STILL APPEARS SMALL HOWEVER...TOO SMALL TO INCLUDE IN TAFS AT THIS TIME. AS WARM ADVECTION CONTINUES INTO FRIDAY...THE LOW LEVEL MOISTURE IS TRAPPED BELOW THE STRENGTHENING INVERSION...SO ANTICIPATE THAT IFR/LIFR CEILINGS WILL PERSIST FOR MUCH OF THE DAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...MW
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
953 PM MST WED DEC 3 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 246 PM MST WED DEC 3 2014 WEAK SHORTWAVE EMBEDDED WITHIN WESTERLY FLOW WILL DEPART THE REGION TONIGHT. BUT NOT BEFORE PRODUCING MOUNTAIN SNOW OVER THE SNOWY AND SIERRA MADRE RANGES AS WELL AS A LIGHT RAIN/SNOW MIX OVER THE ADJACENT LOWER ELEVATIONS. NOT EXPECTING ALL THAT SIGNIFICANT OF AN EVENT...BUT A FEW INCHES OF ACCUMULATION CAN BE EXPECTED OVR THE ABOVE 7500 FEET THRU THE EVENING. HAVE ALSO ADDED SLIGHT CHANCES FOR A RAIN/SNOW SHOWER NORTH OF HWY 26 LATE THIS AFTERNOON...AS THE SHORTWAVE INTERACTS WITH FAIRLY STEEP H7-H5 LAPSE RATES. AGAIN...ANYTHING WOULD BE LIGHT AND ANY CHANCE SHOULD WANE QUICKLY WITH LOSS OF INSOLATION DRIVEN INSTABILITY. A VERY MILD DAY AHEAD FOR THURSDAY AS FLOW BACKS SLIGHTLY TO WEST/SOUTHWEST. H7 TEMPS WARM FROM AROUND -2C TODAY TO FREEZING...WHICH WHEN COMBINED WITH DOWNSLOPE WESTERLY WINDS WILL BOOST HIGHS ON THE ERN PLAINS IN TO THE UPPER 50S AND EVEN SOME LOW 60S. ASIDE FROM SOME LIGHT SNOW OR FLURRY CHANCES OVR THE SNOWY AND SIERRA MADRE RANGES...THURSDAY WILL BE DRY. OTHER THAN THE OCCASIONAL WIND GUST OF 20-30 MPH OVR SOUTHEAST WYOMING...ANTICIPATE NO OTHER WIND CONCERNS. FRIDAY WILL BE A BIT COOLER AS A WEAK/DRY COLD FROPA DROPS SOUTH THRU THE CWFA. EVEN SO...HIGH TEMPERATURES WILL CONTINUE TO BE WELL ABOVE SEASONAL NORMS AS HIGHS REACH THE 40S WEST OF THE LARAMIE RANGE AND LOW 50S OUT ON THE ERN PLAINS. AN UPSTREAM AMPLIFYING UPPER RIDGE WILL PUSH INTO THE AREA FRIDAY NIGHT KEEPING WINDS AND PRECIP CHANCES AT BAY. .LONG TERM...(SATURDAY THROUGH TUESDAY NIGHT) ISSUED AT 246 PM MST WED DEC 3 2014 THE SPLIT FLOW PATTERN WILL REMAIN IN PLACE FOR SATURDAY AND SUNDAY...WITH ONE SHORTWAVE TROUGH MOVING EAST ACROSS THE DESERT SOUTHWEST AND ANOTHER MOVING EAST-SOUTHEAST ACROSS THE NORTHERN ROCKIES AND HIGH PLAINS. THE NORTHERN STREAM WAVE LOOKS TO DEEPEN THE LEESIDE SFC PRESSURE TROUGH ON SATURDAY AND SATURDAY NIGHT...WITH SFC WINDS ACROSS SOUTHEAST WYOMING INCREASING THROUGH THE DAY AND BECOMING STRONG EARLY SUNDAY MORNING. GFS PAINTS WIND SPEEDS OF 45 TO 50 KTS IN THE 800 TO 700 MB LAYER ACROSS THE FORECAST AREA BY 12Z SUNDAY...WHICH COULD TRANSLATE TO A MARGINAL GAP WIND EVENT MAINLY FOR THE WIND PRONE AREAS AS THE GFS ALSO SHOWS THE INVERSION SETTING UP AT MOUNTAIN TOP LEVEL. WINDS WILL BE ON THE BREEZY SIDE ELSEWHERE THRU SUNDAY AS THE LEESIDE TROUGH SHIFTS EAST IN ASSOCIATION WITH THE UPPER WAVE. THE DEEPEST MOISTURE WILL REMAIN BOTH NORTH AND SOUTH OF THE AREA MORE COLLOCATED WITH THE WAVE...SO OUTSIDE OF PERHAPS SOME MOUNTAIN SNOW SHOWERS...CONDITIONS SHOULD REMAIN DRY THROUGH SUNDAY. MODELS THEN SHOW A GENERAL TREND TOWARD DRY NORTHWEST FLOW SUNDAY NIGHT INTO MONDAY...WITH RIDGING BUILDING IN FROM THE WEST. THE NEXT CHANCE FOR PRECIP IS ON TUESDAY AS ANOTHER...ALBEIT WEAKER...SHORTWAVE TROUGH IS PROGGED TO MOVE ACROSS THE ROCKIES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 950 PM MST WED DEC 3 2014 ONLY CONCERNS WEATHERWISE FOR SOUTHEAST WYOMING AIR TERMINALS WILL BE KRWL TONIGHT AS LATEST HRRR SHOWS MVFR/IFR CONDITIONS CLOSE TO THE AIRPORT. DO NOT THINK LOW CLOUDS WILL BE WIDESPREAD ENOUGH TO BRING KRWL DOWN TO IFR...SO WENT MVFR FOR A TIME OVERNIGHT. VFR CONDITIONS ELSEWHERE ACROSS SOUTHEAST WYOMING AND NEBRASKA PANHANDLE. && .FIRE WEATHER... ISSUED AT 246 PM MST WED DEC 3 2014 A QUIET PERIOD TAKING SHAPE THROUGH THE UPCOMING WEEKEND. THE SNOWY AND SIERRA MADRE RANGES MAY SEE A FEW INCHES OF SNOW THROUGH THE EVENING...ESPECIALLY UP AT THE HIGHER PEAKS. THE AREA WILL SEE A REPRIEVE FROM THE STRONGEST WINDS AS WELL THROUGH THE WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...CAH LONG TERM...RJM AVIATION...GCC FIRE WEATHER...CAH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
212 AM MST SAT DEC 6 2014 .SYNOPSIS...ANOTHER WEATHER SYSTEM FROM THE EASTERN PACIFIC WILL BRING A FEW SHOWERS TO THE AREA TODAY. OTHERWISE...EXPECT NEAR TO ABOVE AVERAGE TEMPERATURES INTO NEXT WEEK WITH DRY CONDITIONS. && .DISCUSSION...A WEATHER SYSTEM FROM THE EASTERN PACIFIC WILL TRACK THROUGH THE WESTERN STATES TODAY. THE TAIL END OF THIS SYSTEM WAS PROGGED TO PASS THROUGH SOUTHERN ARIZONA WITH LIMITED MOISTURE THIS FAR SOUTH. THE NAM AND HRRR MODELS WERE REALLY THE ONLY SOLUTIONS THAT SUGGESTED MEASURABLE PRECIPITATION WITH THE LATEST SREF SHOWING THE BEST CHANCES ACROSS THE RIM COUNTRY AND MOUNTAINS. THUS...HAVE DECIDED TO DECREASE PRECIPITATION CHANCES ACROSS MOST OF SOUTHEAST ARIZONA FOR TODAY. OTHERWISE...MODELS SHOWED A SHORTWAVE RIDGE BUILDING OVER THE DESERT SOUTHWEST SUNDAY AND MONDAY...THEN FLATTENING A BIT TUESDAY AS A WEAK SYSTEM PASSES THROUGH THE CENTRAL ROCKIES. MORE RIDGING WEDNESDAY INTO THURSDAY AHEAD OF ANOTHER SYSTEM ENTERING THE WEST COAST. MEDIUM RANGE MODELS SHOWED THIS NEXT SYSTEM BRINGING A GOOD CHANCE OF PRECIPITATION TO THE AREA BY FRIDAY EVENING INTO SATURDAY. DAYTIME TEMPERATURES WILL REMAIN NEAR OR A FEW DEGREES ABOVE NORMAL READINGS THROUGH NEXT WEEK. && .AVIATION...VALID THRU 07/12Z. BKN-OVC HIGH CLOUDS...MAINLY ABOVE 16K FT AGL...WITH FEW-SCT CLOUDS AT 6-10K FT AGL DEVELOPING BY 06/18Z. SLIGHT CHANCE OF -SHRA MAINLY OVER THE HIGHER TERRAIN AND MAINLY AFT 06/18Z. LOCAL AREAS OF BR EARLY THIS MORNING...DIMINISHING BY 06/16Z. WINDS WILL REMAIN LIGHT...GENERALLY LESS THAN 10 KTS THROUGH THE FORECAST PERIOD. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A WEAK SYSTEM WILL MOVE NORTH OF THE REGION TODAY. THIS SYSTEM WILL RESULT IN A SLIGHT CHANCE OF SHOWERS...MAINLY OVER THE HIGHER TERRAIN TODAY AND TONIGHT. WINDS ARE EXPECTED TO BE LIGHT INTO THE MIDDLE OF NEXT WEEK...GENERALLY LESS THAN 15 MPH. HIGH TEMPERATURES WILL BE 2 TO 5 DEGREES ABOVE SEASONAL AVERAGES THROUGH THE WEEKEND AND 4 TO 8 DEGREES ABOVE NORMAL NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
1155 PM PST FRI DEC 5 2014 .SYNOPSIS... ANOTHER WEAK SYSTEM WILL BRING SOME LIGHT SHOWERS INTO THE AREA MAINLY NORTH OF KERN COUNTY TONIGHT. DRY CONDITIONS ARE EXPECTED BY SATURDAY NIGHT WITH NIGHTTIME AND MORNING VALLEY FOG AS HIGH PRESSURE BRIEFLY RETURNS. ANOTHER WEAK SYSTEM IS EXPECTED TO SKIRT ACROSS THE NORTHERN PORTION OF THE STATE ON MONDAY...WITH LIGHT RAIN POSSIBLE NORTH OF FRESNO COUNTY. && .DISCUSSION... QUICK UPDATE TO THE FORECAST TO INCLUDE FOG FOR THE NORTHERN ANTELOPE VALLEY/SOUTHEAST KERN COUNTY AND LOWER POPS CWA-WIDE. POPS...FORCING IS FALLING APART WITH THE SYSTEM TRAVERSES OUR CWA. HRRR AND OTHER HI-RES MODELS AGREE THAT SHOWERS WILL CONTINUE TO DRASTICALLY DECREASE NEXT FEW HOURS THEREFORE HAVE REDUCED POPS MOST AREAS. NEXT UP IS FOG POTENTIAL FOR PARTS OF THE MOJAVE DESERT. VISIBILITY SENSORS THERE ARE ALREADY TRENDING DOWN INTO THE 5-6SM RANGE. BASED ON UPS METHOD/CROSSOVER TEMPERATURES FOG IS LIKELY TO FORM. FOR EXAMPLE...THE XOVER TEMP AT KMHV IS 45F AND CURRENT TEMP IS ALREADY DOWN TO 50 /WITH 100 PERCENT HUMIDITY/. THE FORECAST LOW IS IN THE LOWER 40S. ADDITIONAL SUPPORT INCLUDES THE VEGAS SOUNDING SHOWING A SATURATED BOUNDARY LAYER/INCREASING HUMIDITY WITH HEIGHT. FINALLY...SEVERAL RUNS OF THE HRRR HAVE GENERATED FOG IN THAT AREA OVER THE NEXT FEW HOURS. THEREFORE ADDED FOG TO FORECAST. WILL MONITOR OVERNIGHT FOR POTENTIAL OF A DENSE FOG ADVISORY BUT WILL COVER THE MESSAGE VIA OUR SOCIAL MEDIA CHANNELS FOR NOW. && .PREV DISCUSSION... /ISSUED 348 PM PST FRI DEC 5 2014/ DISCUSSION...IT HAS BEEN A RELATIVELY MILD DAY ACROSS CENTRAL CALIFORNIA TODAY UNDER CLOUDY SKIES AHEAD OF THE NEXT APPROACHING WEAK FRONTAL SYSTEM. RADAR SHOWS ASSOCIATED SHOWERS IMPACTING COASTAL AREAS TO OUR WEST. HIGH RESOLUTION MODELS PROG THESE SCATTERED SHOWERS TO PUSH EAST THROUGH OUR AREA THIS EVENING LINGERING INTO EARLY SATURDAY MORNING...THOUGH THE BEST PRECIP STAYS TO OUR NORTH WITH THE MAIN ENERGY. VALLEY QPF RANGES FROM AROUND 1/10 OF AN INCH NORTH TO JUST A HUNDREDTH OR SO TOWARD KERN COUNTY. HIGHER ELEVATION AMOUNTS SIMILARLY TAPER FROM AROUND A QUARTER INCH NEAR YOSEMITE TO NOTHING IN KERN COUNTY. BRIEF SHORTWAVE RIDGING BEHIND THE SYSTEM YIELDS DRY AND CONTINUED MILD CONDITIONS SATURDAY AND SUNDAY. ANOTHER WEAK RIPPLE TRACKS BY TO THE NORTH BY MONDAY...BRINGING JUST A SLIGHT CHANCE FOR PRECIP NORTH OF FRESNO COUNTY. OTHERWISE...DRY AND MILD CONTINUES INTO MIDWEEK. A MORE SIGNIFICANT SYSTEM...REMNANTS OF A SUPER TYPHOON...IS PROGGED TO SLAM INTO THE WEST COAST BY THURSDAY. MODELS OF COURSE HAVE DIFFERENCES IN TIMING AND STRENGTH OF THIS SYSTEM...BUT ENSEMBLES SUGGEST THERE IS A GOOD CHANCE THAT OUR AREA WILL BE AFFECTED WITH RAIN AND MOUNTAIN SNOW AS WELL AS TYPICAL GUSTY WINDS OVER MOUNTAIN RIDGES AND THROUGH AND BELOW PASSES. THIS WILL BE A SOMEWHAT WARM STORM WITH RELATIVELY HIGH SNOW LEVELS. AS THE EVENT APPROACHES WE WILL BE ABLE TO REFINE TIMING AND AMOUNTS. && .AVIATION... SCATTERED LIGHT RAIN SHOWERS THIS EVENING THRU 12Z SAT...MVFR CEILINGS WITH LOCAL IFR POSSIBLE AT TIMES...MAINLY NORTH OF KERN COUNTY. OTHERWISE EXPECT VFR CONDITIONS TO PREVAIL OVER THE CENTRAL CALIFORNIA INTERIOR OVER THE NEXT 24 HOURS. && .AIR QUALITY ISSUES... NONE. && .CERTAINTY... THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH. THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM. THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD. CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL INFORMATION AND/OR TO PROVIDE FEEDBACK. && .CLIMATE... RECORDS SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR KFAT 12-05 72:1958 40:1963 52:2012 28:1903 KFAT 12-06 68:1995 42:1965 55:2012 28:1891 KFAT 12-07 69:1937 42:1965 52:1950 25:1978 KBFL 12-05 80:1918 43:1965 55:1966 23:1903 KBFL 12-06 77:1916 42:1965 60:1918 22:1903 KBFL 12-07 76:1907 41:1965 53:1950 24:1912 && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ PUBLIC...INIGUEZ AVN/FW...BSO PREV DISCUSSION...JEB SYNOPSIS...BSO WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS MIAMI FL
313 AM EST SAT DEC 6 2014 .SYNOPSIS... GENERALLY DRY CONDITIONS WILL PREVAIL INTO NEXT WEEK...WITH SLIGHTLY COOLER TEMPERATURES ARRIVING BY TUESDAY. && .SHORT TERM /TODAY THROUGH MONDAY/... SURFACE HIGH PRESSURE THAT HAS BEEN WEDGED ON THE LEE SIDE OF THE APPALACHIANS AND DOMINATING SOUTH FLORIDA WEATHER THIS WEEK WILL FINALLY SPREAD OFFSHORE. THIS WILL RESULT IN LIGHTER WINDS FROM A MORE NORTHERLY DIRECTION TODAY. LESS MOIST LOW-LEVELS SHOULD PRECLUDE THE ISOLATED/SCATTERED SHOWER ACTIVITY THAT HAS PESTERED THE ATLANTIC COAST MUCH OF THIS WEEK. A SHORTWAVE TROUGH WILL CROSS THE NORTHEAST CONUS THIS WEEKEND...WITH THE ATTENDANT COLD FRONT ENTERING NORTHERN FLORIDA LATE TONIGHT. THIS FRONT WILL DISSIPATE AS IT PASSES CENTRAL FLORIDA...BUT HIGH PRESSURE WILL STILL BUILD SOUTHWARD INTO SOUTH FLORIDA SUNDAY INTO MONDAY. THE DRYING TREND WILL CONTINUE THIS WEEKEND...AND ABOVE NORMAL TEMPERATURES TODAY WILL GRADUALLY DIP TO NEAR NORMAL BY MONDAY...AS MODIFIED CANADIAN AIRMASS FILTERS IN. .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A DEEPER SHORTWAVE TROUGH /PARTICULARLY IF THE ECMWF VERIFIES/ WILL CROSS NERN STATES LATE MONDAY INTO TUESDAY. ANOTHER...LIKELY DRY FRONT...WILL ENTER NORTH FLORIDA AND THIS TIME CROSS THE PENINSULA. THE MODEL DISCREPANCIES OF THE PAST SEVERAL DAYS HAVE DIMINISHED...AND APPEAR TO BE CONVERGING ON NOTICEABLY COOLER AND DRIER AIRMASS BEHIND THE FRONT FOR TUESDAY THROUGH THURSDAY. TEMPERATURES WILL LIKELY BE SLIGHTLY BELOW NORMAL...WITH MAXIMA MAINLY IN THE LOW 70S...MINIMA RANGING FROM UPPER 40S NW TO AROUND 60F ATLANTIC COAST. FLOW WILL REMAIN N OR NW UNTIL THURSDAY...THEN MODERATING TEMPERATURES AND INCREASING MOISTURE COMMENCE AS WINDS TURN NE. SHOWER CHANCES WILL REMAIN SLIGHT AT BEST THROUGH THE PERIOD. && .AVIATION... LIGHT SHOWERS CONTINUE TO EXIT THE EAST COAST SITES...PUSHING OFF TOWARD THE INTERIOR. LATEST HRRR KEEPS THE TAF SITES DRY THROUGH THE REMAINDER OF THE NIGHT. THEREFORE REMOVED VCSH MENTION. WINDS WILL CONTINUE TO BE GENERALLY EASTERLY AT AROUND 10 KNOTS OR LESS THROUGH THE MORNING AND INTO THE AFTERNOON HOURS BEFORE DECREASING AND BACKING MORE TO THE NORTHEAST INTO THE EVENING HOURS. KAPF SHOULD SEE A NORTHWEST FLOW COMING IN FROM THE GULF OF MEXICO TOWARD THE EARLY TO MID AFTERNOON HOURS. && .MARINE... AS THE CENTER OF HIGH PRESSURE MOVES N/E AWAY FROM WATERS TODAY...WINDS WILL CONTINUE TO SUBSIDE. NE WINDS TODAY WILL TURN NORTHERLY INTO EARLY NEXT WEEK AS WEAK COLD FRONT/NEW HIPRES SPREAD OVER THE WATERS. A MORE SIGNIFICANT FRONT ON TUESDAY MAY RESULT IN INCREASING WINDS AND SEAS FOR WEDNESDAY AND THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 81 64 79 65 / 10 0 10 10 FORT LAUDERDALE 80 68 80 68 / 10 0 10 10 MIAMI 81 67 80 66 / 10 0 10 10 NAPLES 80 63 76 62 / 0 10 10 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...HIGH RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR FLZ168-172- 173. AM...HIGH RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR AMZ630. GM...NONE. && $$ SHORT TERM...23/SK LONG TERM....23/SK AVIATION...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
100 AM EST SAT DEC 6 2014 .AVIATION... LIGHT SHOWERS CONTINUE TO EXIT THE EAST COAST SITES...PUSHING OFF TOWARD THE INTERIOR. LATEST HRRR KEEPS THE TAF SITES DRY THROUGH THE REMAINDER OF THE NIGHT. THEREFORE REMOVED VCSH MENTION. WINDS WILL CONTINUE TO BE GENERALLY EASTERLY AT AROUND 10 KNOTS OR LESS THROUGH THE MORNING AND INTO THE AFTERNOON HOURS BEFORE DECREASING AND BACKING MORE TO THE NORTHEAST INTO THE EVENING HOURS. KAPF SHOULD SEE A NORTHWEST FLOW COMING IN FROM THE GULF OF MEXICO TOWARD THE EARLY TO MID AFTERNOON HOURS. && .PREV DISCUSSION... /ISSUED 958 PM EST FRI DEC 5 2014/ UPDATE... GUIDANCE SHOWS RELATIVELY DRIER AIR ARRIVING THROUGH THE LOW LEVELS, BY SATURDAY MORNING, ACROSS SOUTH FLORIDA. THIS SHOULD BRING AN END TO THE NEARLY PERPETUAL COASTAL AND OFFSHORE SHOWERS BY LATE TONIGHT. OTHERWISE, THE OVERNIGHT WILL BE WARM AND HUMID. PREV DISCUSSION... /ISSUED 303 PM EST FRI DEC 5 2014/ DISCUSSION... THE UPPER LEVEL PATTERN CONSISTED OF HIGH PRESSURE OVER THE SOUTH CENTRAL GULF OF MEXICO...AND A SHORTWAVE MOVING ACROSS THE SOUTHERN PLAINS. AT THE SURFACE...STRONG HIGH PRESSURE WAS CENTERED OVER NEW BRUNSWICK AND NOVA SCOTIA AND STRETCHED DOWN THE EAST COAST. AN AREA OF LOW PRESSURE WAS BEGINNING TO DEVELOP OVER NORTH TEXAS AND OKLAHOMA. EASTERLY FLOW WITH QUICK MOVING SHOWERS WILL CONTINUE THROUGH THE AFTERNOON WITH HIGHS IN TEMPS IN THE LOW 80S. TONIGHT...THE SHORTWAVE WILL PUSH EASTWARD AND SURFACE LOW PRESSURE WILL MOVE QUICKLY NORTHEASTWARD INTO KENTUCKY. WINDS WILL SHIFT TO THE NORTHEAST...AND DRIER AIR WILL BEGIN TO MOVE INTO SOUTH FLORIDA. A FEW LIGHT SHOWERS IN THE EVENING SHOULD GIVE WAY TO DRY CONDITIONS OVERNIGHT. SATURDAY...AN AMPLIFIED PATTERN WILL TAKE PLACE ACROSS THE CONUS AS A COUPLE SHORTWAVES PUSH INTO THE WEST COAST...WITH HIGH PRESSURE EXTENDING FROM MEXICO INTO THE NORTHERN PLAINS AND CANADA. AN UPPER LEVEL SHORTWAVE ACROSS THE SOUTHERN PLAINS WILL DIG ACROSS THE SOUTHERN APPALACHIANS ON SATURDAY. A COLD FRONT WILL PUSH INTO THE SOUTHEAST STATES. A LIGHTER NORTHEASTERLY FLOW WITH MAINLY DRY CONDITIONS WILL PREVAIL. HIGHS ARE FORECAST TO BE IN THE UPPER 70S TO LOWER 80S. SUNDAY...A WEAK COLD FRONT WILL PUSH INTO NORTHERN AND CENTRAL FLORIDA AS HIGH PRESSURE SURGES INTO THE EASTERN CONUS. THE FRONT IS FORECAST TO BE MAINLY DRY AND BECOME DIFFUSE AS IT MOVES INTO CENTRAL FLORIDA. A FEW SHOWERS MAY MOVE SOUTH AND SOUTHWEST OVER THE ATLANTIC WATERS AND TOWARDS PALM BEACH COUNTY IN THE AFTERNOON. OTHERWISE...DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES ARE EXPECTED. MONDAY THROUGH THURSDAY...MODELS BEGIN TO DIVERGE BEGINNING ON MONDAY. THE MODELS DIFFER ON THEIR HANDLING OF THE SHORTWAVES AND THEIR PHASING AS THEY MOVE ACROSS THE GREAT LAKES AND SOUTHEAST ON MONDAY. THE ECMWF KEEPS THE ACTIVITY MORE PHASED AND FURTHER NORTH INITIALLY...AND THEN DEVELOPS A SURFACE LOW OVER THE GULF STREAM AND MOVES IT UP THE EAST COAST. THIS PUSHES A STRONGER FRONT THROUGH SOUTH FLORIDA ON TUESDAY...WITH NORTHWESTERLY FLOW THE REST OF THE WEEK. THE GFS HAS A MUCH WEAKER LOW OVER THE EAST COAST...AND HAS THE NORTHERN LOW OVER CANADA AS THE DOMINANT ONE. THIS PUSHES THROUGH A MUCH WEAKER BOUNDARY...WITH HIGH PRESSURE MOVING INTO THE SOUTHEAST BY THURSDAY. THIS WOULD RESULT IN NORTHEASTERLY WINDS RETURNING TO THE REGION...ENDING THE COOLER CONDITIONS. THE MOST RECENT RUN OF THE GFS HAS TRENDED COOLER...BUT IS STILL WARMER THAN THE ECMWF. THE FORECAST WILL LEAN MORE TOWARDS THE ECMWF SOLUTION...WITH HIGHS IN THE LOW 70S AND LOWS MAINLY IN THE 50S. MARINE... HIGH PRESSURE WILL WEAKEN NORTH OF THE REGION ON SATURDAY AS A COLD FRONT PUSHES INTO THE SOUTHEAST. WINDS WILL SHIFT TO THE NORTHEAST. THE WEAK FRONT WILL PUSH INTO CENTRAL FLORIDA ON SUNDAY...WITH WEAK NORTHEASTERLY FLOW CONTINUING. A FRONT IS FORECAST TO PUSH THROUGH THE REGION EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 79 64 78 63 / 10 0 20 20 FORT LAUDERDALE 80 67 79 64 / 10 0 10 10 MIAMI 81 66 80 63 / 10 0 10 10 NAPLES 81 62 77 59 / 0 0 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...HIGH RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR FLZ168-172- 173. AM...HIGH RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR AMZ630. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
356 AM EST SAT DEC 6 2014 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 356 AM EST SAT DEC 6 2014 RAINFALL WILL COME TO AN END TODAY AS LOW PRESSURE GRADUALLY EXITS THE REGION. CLOUD COVER WILL PERSIST HOWEVER AS AMPLE LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG INVERSION. DRY WEATHER WILL CONTINUE THROUGH SUNDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. A SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE GREAT LAKES MONDAY AND MONDAY NIGHT MAY PRODUCE SOME LIGHT RAIN ACROSS PORTIONS OF THE AREA. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD. && .NEAR TERM /TODAY/... ISSUED AT 356 AM EST SAT DEC 6 2014 BETWEEN HRRR AND EXTRAPOLATION FROM LATEST RADAR TRENDS...EXPECT PRECIPITATION TO COME TO AN END ACROSS CENTRAL INDIANA BY NOON...AND WILL RAPIDLY TAPER OFF POPS AS SUCH FROM WEST TO EAST. STRONG LOW LEVEL INVERSION WILL REMAIN ACROSS THE AREA IN THE WAKE OF THE LOW PRESSURE SYSTEM WITH MOISTURE TRAPPED...THUS IT APPEARS THAT MODEL GUIDANCE IS CLEARING SKIES OUT FAR TOO QUICKLY. HAVE DELAYED ANY CLEARING WHATSOEVER INTO THE AFTERNOON AND THERE IS SOME CHANCE EVEN THIS IS TOO EARLY. LEANED SLIGHTLY COOLER THAN GUIDANCE AS A RESULT OF THIS AMPLE CLOUD COVER AND ONGOING COLD ADVECTION THROUGH THE DAY. MAY SEE HIGH TEMPERATURES EARLY IN THE DAY IN SOME LOCATIONS WITH TEMPERATURES STEADY OR SLOWLY FALLING LATE IN THE DAY. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 356 AM EST SAT DEC 6 2014 LATEST MODELS ARE COMING IN WETTER WITH THE SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. WILL HAVE TO CARRY SOME POPS MONDAY AND INTO MONDAY EVENING...BUT WITH SOUNDINGS ONLY BRIEFLY SATURATING MONDAY...AND DRYING QUICKLY FROM ALOFT LATE MONDAY NIGHT...WILL GO NO FURTHER THAN LOW CHANCE POPS AND WILL END PRECIP BY 06Z MONDAY NIGHT. MONDAY EVENING...PRECIP MAY COME MORE IN THE FORM OF DRIZZLE AS DRY AIR WORKS INTO THE AREA ALOFT BUT WITH WEAKLY POSITIVE OMEGA NOTED IN MOIST LOW LEVELS. EXPECT THAT PRECIP WILL HAVE ENDED BY THE TIME ANY FREEZING OR NEAR FREEZING TEMPERATURES MOVE INTO THE AREA. MODEL CONSENSUS APPEARED TO TRACK RELATIVELY WELL WITH LOW LEVEL THICKNESS PROGS...ASIDE FROM A FEW MINOR TWEAKS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 060900Z IND TAF UPDATE/... RADAR TRENDS SUGGEST AT LAST THE END OF THE RAIN FALL IS NEAR. BACK EDGE OF PRECIP APPEARS OVER EAST CENTRAL ILLINOIS...PROGRESSING EASTWARD. OBS UPSTREAM STILL SHOW EXTENSIVE MVFR TO IFR CONDITIONS. THUS BASED UPON LATEST TRENDS...EXPECT ONE MORE PERIOD OF LIGHT RAIN AT IND AS THE BACK EDGE OF THE PRECIP WORKS ACROSS THE STATE. IMPROVEMENT TO VFR STILL APPEARS GRADUAL AND HEATING...MIXING AND DRIER AIR ARRIVING ON NORTHERLY WINDS BY LATE THIS MORNING. /DISCUSSION FOR THE 060600Z TAF ISSUANCE/... ISSUED AT 1030 PM EST FRI DEC 5 2014 IFR AND WORSE CONDITIONS EXPECTED TO BE THE MOST PREVALENT FLIGHT CATEGORIES THROUGH THE NIGHT. RADAR TRENDS AND 02Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT WITH MOSTLY A LIGHT INTENSITY BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. SHOULD SEE CONDITIONS IMPROVE TO MVFR AFTER 12Z FROM NORTHWEST TO SOUTHEAST. DO NOT EXPECT MUCH CLEARING OVERNIGHT SATURDAY NIGHT...BUT COULD SEE A FEW BREAKS. WINDS WILL BE BRIEFLY EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. SPEED AND DIRECTION SHOULD BE SIMILAR DURING THE DAY AND BECOME NORTHEAST 10 KNOTS OR LESS AFTER 00Z TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...NIELD NEAR TERM...NIELD SHORT TERM...NIELD LONG TERM...PUMA AVIATION...MK/JP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
340 AM EST SAT DEC 6 2014 .UPDATE... AVIATION SECTIONS UPDATED. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 953 PM EST FRI DEC 5 2014 FORECAST IS IN GOOD SHAPE AND MADE NO MAJOR CHANGES. RAIN WILL CONTINUE ACROSS THE AREA AS LOW PRESSURE MOVES SOUTH OF CENTRAL INDIANA AND AN UPPER TROUGH MOVES INTO THE AREA. LATER TONIGHT AS FORCING SHIFTS EAST...RAIN WILL DIMINISH SOME FROM NORTHWEST TO SOUTHEAST. WARM AIR WILL REMAIN JUST SOUTH OF THE AREA. PREVIOUS DISCUSSION FOLLOWS... RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 060900Z IND TAF UPDATE/... RADAR TRENDS SUGGEST AT LAST THE END OF THE RAIN FALL IS NEAR. BACK EDGE OF PRECIP APPEARS OVER EAST CENTRAL INDIANA...PROGRESSING EASTWARD. OBS UPSTREAM STILL SHOW EXTENSIVE MVFR TO IFR CONDITIONS. THUS BASED UPON LATEST TRENDS...EXPECT ONE MORE PERIOD OF LIGHT RAIN AT IND AS THE BACK EDGE OF THE PRECIP WORKS ACROSS THE STATE. IMPROVEMENT TO VFR STILL APPEARS GRADUAL AND HEATING...MIXING AND DRIER AIR ARRIVING ON NORTHERLY WINDS BY LATE THIS MORNING. /DISCUSSION FOR THE 060600Z TAF ISSUANCE/... ISSUED AT 1030 PM EST FRI DEC 5 2014 IFR AND WORSE CONDITIONS EXPECTED TO BE THE MOST PREVALENT FLIGHT CATEGORIES THROUGH THE NIGHT. RADAR TRENDS AND 02Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT WITH MOSTLY A LIGHT INTENSITY BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. SHOULD SEE CONDITIONS IMPROVE TO MVFR AFTER 12Z FROM NORTHWEST TO SOUTHEAST. DO NOT EXPECT MUCH CLEARING OVERNIGHT SATURDAY NIGHT...BUT COULD SEE A FEW BREAKS. WINDS WILL BE BRIEFLY EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. SPEED AND DIRECTION SHOULD BE SIMILAR DURING THE DAY AND BECOME NORTHEAST 10 KNOTS OR LESS AFTER 00Z TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN/50 SHORT TERM...RYAN LONG TERM....PUMA AVIATION...MK/JP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
243 AM EST SAT DEC 6 2014 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 347 PM EST FRI DEC 5 2014 WIDESPREAD RAIN WILL CONTINUE THROUGH SATURDAY MORNING AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. WITH THE EXCEPTION OF A FEW SHOWERS MONDAY AS LOW PRESSURE PASSES THROUGH THE GREAT LAKES...DRY AND SEASONABLY COOL WEATHER CAN BE EXPECTED THROUGH MUCH OF NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 953 PM EST FRI DEC 5 2014 FORECAST IS IN GOOD SHAPE AND MADE NO MAJOR CHANGES. RAIN WILL CONTINUE ACROSS THE AREA AS LOW PRESSURE MOVES SOUTH OF CENTRAL INDIANA AND AN UPPER TROUGH MOVES INTO THE AREA. LATER TONIGHT AS FORCING SHIFTS EAST...RAIN WILL DIMINISH SOME FROM NORTHWEST TO SOUTHEAST. WARM AIR WILL REMAIN JUST SOUTH OF THE AREA. PREVIOUS DISCUSSION FOLLOWS... RAIN CONTINUES ACROSS THE FORECAST AREA THIS AFTERNOON...AND EXPECT ONLY TO INCREASE FURTHER IN INTENSITY OVER THE NEXT SEVERAL HOURS WITH THE APPROACH OF LOW PRESSURE. TEMPS RANGED FROM THE UPPER 30S NORTH TO UPPER 40S ACROSS FAR SOUTHERN COUNTIES AT 20Z. A RAW WET NIGHT UPCOMING AS LOW PRESSURE CURRENTLY OVER THE OZARKS TRACKS E/NE ALONG THE OHIO RIVER TONIGHT. MODEL GUIDANCE IN EXCELLENT AGREEMENT ON SPREADING ANOTHER WAVE OF HEAVIER CONVECTIVE RAINFALL INTO THE FORECAST AREA LATE THIS AFTERNOON THROUGH THE EVENING. FOCUS FOR THE HEAVIEST RAINS REMAINS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA BETWEEN 00-06Z AS STRONGER LOW LEVEL CONVERGENCE ALIGNS ALONG THE 850MB BAROCLINIC ZONE AND AREA OF ENHANCED ISENTROPIC LIFT. A LOW LEVEL JET OVER THE TENNESSEE VALLEY WILL TRANSPORT DEEPER MOISTURE UP INTO THE REGION AS WELL. APPROACH OF THE UPPER WAVE WILL PROMOTE DIFFLUENCE ALOFT...FURTHER ASSISTING LIFT FOR EFFICIENT RAINFALL. THERE IS SOME WEAK ELEVATED INSTABILITY PRESENT...BUT JUST DO NOT SEE ENOUGH TO JUSTIFY AN ISOLATED THUNDER MENTION TONIGHT. BETTER THREAT FOR A FEW STORMS WILL EXIST CLOSER TO THE SURFACE LOW TRACK ALONG THE OHIO RIVER. POTENTIAL EXISTS FOR UP TO 1.5 INCHES ALONG AND SOUTH OF I-70 BY SATURDAY MORNING. WILL CONTINUE WITH CATEGORICAL POPS TONIGHT. HEAVIER RAINS WILL BEGIN TO SHIFT EAST AFTER 06Z...BUT LINGERING MID LEVEL DEFORMATION BAND WILL MAINTAIN LIGHTER RAIN FOR MUCH OF THE REST OF THE NIGHT. HRRR AND WRF-NMM/ARW BRING BACK END OF THE RAIN INTO THE NORTHERN WABASH VALLEY AROUND OR SHORTLY BEFORE DAYBREAK. WINDS WILL PICK UP LATE TONIGHT AS WELL AS A BRISK NORTHERLY FLOW DEVELOPS BEHIND THE SURFACE LOW. TEMPS...MOS APPEARS A BIT AGGRESSIVE IN BRINGING THE COLDER AIR IN PRIOR TO 12Z. GENERALLY TRENDED A DEGREE OR TWO ABOVE MAVMOS GUIDANCE WITH LOWS RANGING FROM THE MID 30S NORTH TO LOWER 40S SOUTH. && .SHORT TERM /SATURDAY THROUGH MONDAY/... ISSUED AT 347 PM EST FRI DEC 5 2014 FORECAST CHALLENGES FOCUS ON THE DEPARTURE OF THE RAIN SATURDAY MORNING...AND POSSIBILITY FOR LIGHT PRECIP WITH A WEAK SYSTEM ON MONDAY. THE UPPER WAVE AND SURFACE LOW WILL CONTINUE TO MOVE AWAY TO THE EAST WITH LIGHT RAIN ENDING FROM NORTHWEST TO SOUTHEAST DURING THE MORNING. WRF DATA LOOKS VERY GOOD WITH RESPECT TO TIMING AND WAS UTILIZED FOR MORNING POPS. EXPECT THE ENTIRE FORECAST AREA WILL BE FREE OF PRECIP AROUND MIDDAY. DRIER AIR ALOFT WILL QUICKLY ADVECT INTO THE REGION WITH STRONG HIGH PRESSURE SATURDAY AFTERNOON...BUT RH PROGS AND MODEL SOUNDINGS INDICATE LINGERING LOW LEVEL MOISTURE REMAINING TRAPPED BENEATH A SLOWLY WEAKENING INVERSION. EXPECT LOWER CLOUDS TO LINGER AS A RESULT...WITH FULL CLEARING OF THE CLOUD DECK NOT COMING UNTIL SATURDAY EVENING AS STRONGER SUBSIDENCE ENABLES DRIER AIR TO INFILTRATE THE NEAR SURFACE LAYER. HIGH PRESSURE RIDGE WILL DRIFT SLOWLY THROUGH THE GREAT LAKES SATURDAY NIGHT AND SUNDAY...PROVIDING A DRY COOL E/NE FLOW ACROSS CENTRAL INDIANA. EXPECT ABUNDANT SUNSHINE ON SUNDAY...WHICH AMAZINGLY WOULD BE THE FIRST DAY WITH EXTENDED SUNSHINE AND BLUE SKIES FOR MANY SINCE NOVEMBER 21. MID AND HIGH LEVEL CLOUDS WILL INCREASE AGAIN BEGINNING SUNDAY NIGHT WITH SKIES BECOMING FAIRLY CLOUDY MONDAY AS AN UPPER WAVE AND ASSOCIATED LOW PRESSURE ASSOCIATED WITH THE NORTHERN JET STREAM TRACK INTO THE GREAT LAKES. DESPITE INCREASING ISENTROPIC LIFT AND HINT OF SOME DEVELOPING LOW LEVEL CONVERGENCE...MOISTURE PROFILES LARGELY LOOK UNIMPRESSIVE AND FOCUSED PRIMARILY ABOVE 10KFT. HAVE A HARD TIME JUSTIFYING MUCH HIGHER THAN LOW CHANCE POPS AS THE SYSTEM PASSES THROUGH. ENOUGH COLD AIR PRESENT THAT MAY SEE A MIXTURE OF LIGHT SNOW AND RAIN IN THE NORTHERN WABASH VALLEY MONDAY MORNING BEFORE PRECIP TRANSITIONS TO ALL RAIN. REGARDLESS...QPF VALUES AT THIS POINT LOOK NO HIGHER THAN A FEW HUNDREDTHS. TEMPS...LEANED CLOSER TO COOLER METMOS FOR SATURDAY HIGHS WITH THE LINGER LOW CLOUDS. WENT NEAR MOS FOR SUNDAY THEN UNDERCUT FOR MONDAY AND LEANED CLOSER TO ECMWF ENSEMBLE MEAN TEMPS. DESPITE WARM ADVECTION AHEAD OF THE SURFACE LOW...MEXMOS LOOKS TOO AGGRESSIVE WITH WARMING TEMPS. LEANED TOWARDS WARMER METMOS FOR SATURDAY NIGHT LOWS AND TOOK A MODEL BLEND FOR SUNDAY NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 060600Z TAF ISSUANCE/... ISSUED AT 1030 PM EST FRI DEC 5 2014 IFR AND WORSE CONDITIONS EXPECTED TO BE THE MOST PREVALENT FLIGHT CATEGORIES THROUGH THE NIGHT. RADAR TRENDS AND 02Z RAPID REFRESH REFLECTIVITY PROGS SUGGEST THE RAIN WILL CONTINUE THROUGH THE NIGHT WITH MOSTLY A LIGHT INTENSITY BEFORE ENDING AFTER 09Z AT LAF...11Z AT HUF...12Z AT IND AND 13Z AT BMG. SHOULD SEE CONDITIONS IMPROVE TO MVFR AFTER 12Z FROM NORTHWEST TO SOUTHEAST. DO NOT EXPECT MUCH CLEARING OVERNIGHT SATURDAY NIGHT...BUT COULD SEE A FEW BREAKS. WINDS WILL BE BRIEFLY EAST AND NORTHEAST NEAR 10 KNOTS AND THEN BECOME NORTH AND INCREASE TO NEAR 15 KNOTS OVERNIGHT WITH GUSTS TO AROUND 20 KNOTS. SPEED AND DIRECTION SHOULD BE SIMILAR DURING THE DAY AND BECOME NORTHEAST 10 KNOTS OR LESS AFTER 00Z TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN/50 SHORT TERM...RYAN LONG TERM....PUMA AVIATION...MK VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1000 PM MST FRI DEC 5 2014 .SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY) ISSUED AT 1246 PM MST FRI DEC 5 2014 LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW RIDGING BUILDING ACROSS INTER-MOUNTAIN WEST...WITH A SHORTWAVE TROUGH CENTERED OVER EASTERN KANSAS. SUBSIDENCE/CLEARING IS IN PLACE OVER OUR CWA. AT THE THE SURFACE...PRE FRONTAL LOW PRESSURE IS IN PLACE ACROSS KANSAS AND EASTERN COLORADO WITH A WEAK COLD FRONT OVER SOUTHERN NEBRASKA. AHEAD OF THE COLD FRONT TEMPERATURES HAVE WARMED TO NEAR 60 DEGREES OVER MUCH OF THE CWA WITH A WELL MIXED AIR MASS AND SURFACE TROUGH IN PLACE. DRY FORECAST CONTINUES THROUGH SATURDAY AFTERNOON AS RIDGE TRANSITIONS EASTWARD...AND SUBSIDENT/DRY AIR MASS LINGERS. THIS AFTERNOON-TONIGHT...THE COLD FRONT OVER NEBRASKA WILL DROP SOUTH THIS LATE THIS AFTERNOON AND EVENING WITH SURFACE HIGH PRESSURE SETTLING IN FROM THE NORTHERN PLAINS. A COOLER/DRIER AIR MASS WILL ACCOMPANY THIS HIGH PRESSURE SYSTEM...RETURNING OVERNIGHT LOWS TO SEASONAL VALUES AROUND 20F. NAM/SREF CONTINUE TO HINT AT SURFACE RH VALUES APPROACHING SATURATION AND POSSIBLE FOG DEVELOPMENT. SOUNDINGS INDICATE THIS WILL BE VERY SHALLOW MOIST LAYER...AND A DRY BL WILL GENERALLY INHIBIT FOG/STRATUS DEVELOPMENT TONIGHT. HRRR/RAP CURRENTLY SHOWING NO FOG DEVELOPMENT OVER OUR CWA. WHILE WE COULD SEE SOME SHALLOW FOG DEVELOPMENT...AT THIS POINT CONFIDENCE IS JUST TOO LOW TO ADD. SATURDAY...SHORTWAVE RIDING WILL TRANSITION THROUGH THE PLAINS ON SATURDAY...WITH A SHORTWAVE TROUGH MOVING OUT OF THE GREAT BASIN TOWARDS THE CENTRAL ROCKIES SATURDAY AFTERNOON. SW FLOW ALOFT WILL DEVELOP BY SATURDAY AFTERNOON BETWEEN THESE FEATURES...WITH INCREASING MID TO HIGH CLOUD COVER THROUGH THE DAY FROM THE WEST TO THE EAST. LEE TROUGH AND SOUTHERLY FLOW WILL DEVELOP IN RESPONSE TO THIS SHIFT IN FLOW ALOFT...SUPPORTING WAA ACROSS OUR CWA AS THE SURFACE HIGH RETREATS EASTWARD. NOT A LOT OF CONFIDENCE IN WHICH WILL WIN OUT: WAA WITH SOUTHERLY FLOW OR LIMITED DIURNAL HEATING DUE TO INCREASING CLOUD COVER. I ONLY MADE MINOR ADJUSTMENTS TO HIGH TEMP FORECAST...WHICH HAS HIGHS NEAR 50 IN THE WEST AND THE MID 40S IN THE EAST. I COULD SEE LOCATIONS IN THE WEST APPROACHING THE MID 50S IF CLOUD COVER HAS MINIMAL IMPACT AND WE ACHIEVE FULL DAYTIME MIXING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 222 PM MST FRI DEC 5 2014 AN UPPER TROUGH WILL MOVE INTO THE CENTRAL PLAINS SATURDAY NIGHT FOLLOWED BY NORTHWEST FLOW SUNDAY. A RIDGE WILL MOVE EAST FROM THE ROCKIES AND INTO THE PLAINS MONDAY. A SURFACE TROUGH WILL BE OVER EASTERN COLORADO SATURDAY NIGHT AND THEN SHIFT EAST SUNDAY. SURFACE HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS SUNDAY AND MONDAY. THE UPPER TROUGH THAT COMES THROUGH THE FA SATURDAY NIGHT WILL BE LACKING FOR MOISTURE. MOISTURE IMPROVES SOME AS THE SYSTEM EXITS THE FAR EASTERN FA SUNDAY MORNING. FORECAST SOUNDINGS ACROSS THE FA SATURDAY NIGHT SHOW CLOUD BASES FROM 8 TO 11KFT. FORECAST SOUNDINGS SHOW SATURATION NEAR THE SURFACE EAST OF THE COLORADO LINE FOR STRATUS/FOG AND LIGHT DRIZZLE WITH SURFACE TEMPERATURES ABOVE FREEZING. SUBSIDENCE MOVES INTO THE FA LATE SUNDAY MORNING AND CONTINUES THROUGH MONDAY. CONSEQUENTLY POPS WILL BE NIL FROM SATURDAY NIGHT THROUGH MONDAY. MIN TEMPERATURES SATURDAY AND SUNDAY NIGHTS WILL VARY FROM THE UPPER 20S TO AROUND 30. MAX TEMPERATURES SUNDAY SHOULD RANGE FROM 45 TO 50. MAX TEMPERATURES MONDAY SHOULD WARM TO THE MID AND UPPER 50S. IN THE EXTENDED...(MONDAY NIGHT THROUGH FRIDAY)...A RIDGE WILL PERSIST OVER THE CENTRAL PLAINS THROUGH THURSDAY AND THEN SHIFT EAST FRIDAY WITH ZONAL FLOW EAST OF THE ROCKIES. SURFACE HIGH PRESSURE WILL CONTINUE OVER THE CENTRAL PLAINS THROUGH TUESDAY. A TROUGH MOVES INTO EASTERN COLORADO THURSDAY AND FRIDAY AS HIGH PRESSURE DRIFTS EAST. THE GFS BRINGS A SHORTWAVE THROUGH TUESDAY NIGHT WHILE THE ECMWF KEEPS IT MUCH FURTHER NORTH. ALSO GFS SOUNDINGS SHOW VERY SHALLOW MOISTURE WITH THE SYSTEM. FOR NOW WILL KEEP SILENT POPS FOR TUESDAY NIGHT. AS A RESULT THE ENTIRE EXTENDED FORECAST WILL BE DRY WITH NO OTHER SIGNIFICANT FORCING FOR THE REMAINING PERIODS. MAX TEMPERATURES WILL VARY FROM THE MID 50S TO THE MID AND UPPER 50S THURSDAY AND FRIDAY. MIN TEMPERATURES WILL COOL TO THE UPPER 20S TO AROUND 30. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1000 PM MST FRI DEC 5 2014 FOR KGLD AND KMCK...VFR THROUGH THE PERIOD. SFC HIGH CURRENTLY INFLUENCING THE AREAS WEATHER WILL SLOWLY MOVE EAST OVERNIGHT WITH LOW PRESSURE DEEPENING ALONG THE FRONT RANGE. THE PRESSURE GRADIENT BETWEEN THE TWO WILL SLOWLY STRENGTHEN DURING THE DAY SATURDAY. LIGHT/VARIABLE WINDS AT TAF ISSUANCE THROUGH ROUGHLY 15Z. AFTER 15Z SOUTHEAST WINDS SLOWLY INCREASE DURING THE DAY WITH GUSTS AROUND 20-25KTS AT KGLD BY 20Z...CONTINUING THROUGH THE REST OF THE TAF PERIOD. AT KMCK ONLY 10KT WINDS FROM THE SOUTHEAST EXPECTED AFTER 21Z. MID AND HIGH CLOUDS INCREASE FROM THE SOUTHWEST AFTER 17Z. WILL NEED TO MONITOR CIGS/VIS AT KMCK AT THE TAIL END OF THE TAF PERIOD AS ABUNDANT BOUNDARY LAYER MOISTURE MOVES TOWARD THE TERMINAL FROM THE EAST. CURRENT INDICATIONS SUGGEST MVFR/IFR CONDITIONS POSSIBLE JUST AFTER 06Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...FS AVIATION...99
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1157 PM CST FRI DEC 5 2014 .AVIATION... FOR THE 06/06Z TAFS...A FEW SHWRS CONTINUE TO FORM ALONG AND JUST AHEAD OF A COLD FRONT WHICH IS JUST EAST OF A LINE FROM TXK...GGG TO JSO. SHWRS AND POSSIBLY A FEW EMBEDDED TSTMS WILL LIKELY INCREASE AFTER MIDNIGHT THROUGH EARLY SATURDAY MORNING WITH FRONTAL FORCING. MVFR/IFR CIGS WILL GRADUALLY OVERTAKE THE REGION BOTH AHEAD OF AND BEHIND THE FRONT...PERSISTING THROUGH THE MORNING HOURS SATURDAY AND POSSIBLY EXTENDING INTO THE EARLY AFTERNOON HOURS AT OUR ERN TERMINAL SITES. LIGHT SOUTH WINDS AHEAD OF THE FRONT WILL QUICKLY SHIFT N/NW BEHIND THE FRONT WITH SPEEDS NEAR 10 KTS IN ADDITION TO A FEW HIGHER GUSTS. /19/ && .PREV DISCUSSION... /ISSUED 856 PM CST FRI DEC 5 2014/ DISCUSSION... FRONTAL BOUNDARY AS OF 8 PM WAS ORIENTED NEAR A FYV...FSM... PRX...SEP LINE MOVING SLOWLY SOUTH AND EAST. A NARROW LINE OF MOSTLY SHOWERS HAD DEVELOPED ALONG AND JUST AHEAD OF THIS BOUNDARY ACROSS PORTIONS OF CENTRAL/SW AR INTO EXTREME SE OK AND PORTIONS OF NE TX. THIS LINE LOOKED A LITTLE BETTER A COUPLE OF HOURS AGO BUT WITH THE LOSS OF DAYTIME HEATING AND INSTABILITY LOOKING VERY WEAK...NOT EXPECTING MUCH IN THE OF CONVECTION BUT CANNOT RULE OUT AN ISOLATED LIGHTNING STRIKE THROUGHOUT THE NIGHT. FRONT IS EXPECTED TO BE NEAR THE I-30 CORRIDOR BY MIDNIGHT AND JUST EAST OF A LFK...SHV...ELD LINE BY 12Z IN THE MORNING. FOR THE UPDATE...HAVE ORIENTED POPS HIGHEST ACROSS OUR EASTERN MOST ZONES FOR THE REMAINDER OF THE NIGHT. THIS IS IN GOOD OVERALL AGREEMENT WITH THE HRRR AND THE 00Z NAM OUTPUT WHICH PUTS THE BEST QPF PROBABILITIES WHERE THE HIGHER MOISTURE CONTENT RESIDES. ALSO ADDED THE LIKELIHOOD OF PATCHY DENSE FOG ACROSS ALL BUT OUR EXTREME NW ZONES. TEMP/DEWPOINT DEPRESSIONS ARE VERY LOW ATTM AND WITH THE VERY MOIST LOW LEVEL ATMOSPHERE PRESENT...UNTIL THE FRONT COMES THROUGH...FOG IS A PRETTY GOOD BET OVERNIGHT. NO ADDITIONAL CHANGES WERE NECESSARY THIS EVENING...UPDATE OUT SHORTLY...13. && .PRELIMINARY POINT TEMPS/POPS... SHV 62 68 43 54 42 / 40 0 0 10 10 MLU 62 68 42 55 41 / 50 10 0 10 10 DEQ 52 61 39 49 38 / 10 0 0 10 10 TXK 55 64 41 51 39 / 30 0 0 10 10 ELD 58 68 41 51 39 / 50 0 0 10 10 TYR 55 66 45 55 42 / 20 0 0 20 20 GGG 57 68 43 54 42 / 20 0 0 10 10 LFK 62 71 48 57 46 / 20 10 10 20 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 19
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
334 AM EST SAT DEC 6 2014 .SYNOPSIS... CROSSING LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE UPPER OHIO VALLEY REGION TODAY. && .NEAR TERM /THROUGH TODAY/... NO MAJOR CHANGES WERE NEEDED FOR THE PRE DAWN UPDATE AS LOW PRES MOVG UP THE OHIO VALLEY WL MAINTAIN RAIN ACROSS THE REGION INTO THE AFTERNOON. ADDITIONAL BASIN AVG FORECAST RAINFALL WAS GENLY PROGGED AT APPROX A HALF TO THREE QUARTERS OF AN INCH USING SMOOTHED RFC GUIDANCE AND MORE REASONABLE RAP AND GFS ASCENT FIELDS...A HEALTHY AND PROLONGED RAINFALL THAT IS NOT EXPECTED TO CAUSE PROBLEMS. PASSAGE OF THE LOW WL INITIATE THE COLD FRONTAL INVASION LTR TDA AND INTO THE EVE. RESIDUAL RAIN WL THUS TURN TO SNOW LATE IN THE DAY...BUT RAPIDLY INCRSG SBSDNC/LOW INVERSION LVLS WL ENSURE A LACK OF ACCUMULATION POTENTIAL. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... RMNG SHWRS OF RAIN AND SNOW WL CONT TO DCRS IN COVERAGE THIS EVE. BLDG HIGH PRES THEREAFTER WL MAINTAIN DRY WEA UNTIL THE APCH OF THE NXT UPR TROF LATE ON MONDAY. SRN STREAM SHRTWV THROUGH THAT TROF IS CURRENTLY PROGGED TO SPIN UP A COASTAL LOW BY MONDAY...NEWD PROGRESS OF WHICH IS CURRENTLY PROGGED TO RMN SUFFICIENTLY E TO FOREGO PROBLEM CONTRIBUTION FOR THE UPR OH REGION. NEVERTHELESS...PCPN CHCS WL INCRS ON MON NGT INTO TUESDAY AS ISENTROPIC LIFT...WARM MOIST ADVCTN DVLPS ON THE ERN FLANKS OF THE HIGH AMPLITUDE ERN CONUS TROF. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A DEEP ERN CONUS TROF IS PROGGED TO PERSIST THRU ERLY INTO THE WKEND AS COASTAL SFC LOW PRES TRACKS UP THE E COAST. FCST SNW SHWR CHCS INTO WED NGT UNTIL THE LOW AND UPR SPPRT EXITS THE RGN. A WK SRTWV IS PROGGED TO ROTATE THRU THE GT LKS ARND THE MAIN TROF FRI THOUGH WITH BLDG SFC HIGH PRES UNDER THE TROF KEPT A DRY FCST. BLO SEASONAL TEMPS SHOULD RTN TO NR AVG BY LT WK. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... WDSPRD IFR/OCNL LIFR CONDS ARE EXPD TO CONT TDA AS UPR OH VLY LOW PRES BRINGS RAIN TO THE RGN. INCRG NRLY WNDS AND COND IMPROVEMENT TO LOW END MVFR ARE EXPD BY THIS EVE AS THE SFC LOW SHIFTS E AND RAIN TAPERS OFF. OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RSTRNS ARE EXPD MON NGT THRU WED AS LOW PRES BRINGS SNW SHWRS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/07
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1248 AM EST SAT DEC 6 2014 .SYNOPSIS... CROSSING LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE UPPER OHIO VALLEY REGION TODAY. && .NEAR TERM /THROUGH TODAY/... NO MAJOR CHANGES WERE NEEDED FOR THE POST MIDNGT UPDATE AS LOW PRES MOVG UP THE OHIO VALLEY WL MAINTAIN RAIN ACROSS THE REGION INTO THE AFTERNOON. ADDITIONAL BASIN AVG FORECAST RAINFALL WAS GENLY PROGGED AT APPROX A HALF TO THREE QUARTERS OF AN INCH USING SMOOTHED RFC GUIDANCE AND MORE REASONABLE RAP AND GFS ASCENT FIELDS...A HEALTHY AND PROLONGED RAINFALL THAT IS NOT EXPECTED TO CAUSE PROBLEMS. PASSAGE OF THE LOW WL INITIATE THE COLD FRONTAL INVASION LTR TDA AND INTO THE EVE. RESIDUAL RAIN WL THUS TURN TO SNOW LATE IN THE DAY...BUT RAPIDLY INCRSG SBSDNC/LOW INVERSION LVLS WL ENSURE A LACK OF ACCUMULATION POTENTIAL. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... RMNG SHWRS OF RAIN AND SNOW WL CONT TO DCRS IN COVERAGE THIS EVE. BLDG HIGH PRES THEREAFTER WL MAINTAIN DRY WEA UNTIL THE APCH OF THE NXT UPR TROF LATE ON MONDAY. SRN STREAM SHRTWV IS CURRENTLY PROGGED TO SPIN UP A COASTAL LOW BY MONDAY...NEWD PROGRESS OF WHICH IS CURRENTLY PROGGED TO RMN SUFFICIENTLY E TO FOREGO PROBLEMS FOR THE UPR OH REGION. NEVERTHELESS...PCPN CHCS WL INCRS ON MON NGT INTO TUESDAY AS ISENTROPIC LIFT...WARM MOIST ADVCTN DVLPS ON THE ERN FLANKS OF THE HIGH AMPLITUDE ERN CONUS TROF. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... CHANGES TO THE EXTENDED WERE BASED ON A BLEND OF THE NEW WPC PROGS AND 12Z GFS WHICH HAVE SHIFTED TOWARD THE 00Z ECMWF SOLUTION MID WEEK WITH CLSOED LOW DEVELOPING OVER THE NORTHEAST AND A COASTAL STORM POSSIBLE INTO NEW ENGLAND. MID WEEK TEMPERATURES ADJUSTED COLDER WITH SNOW SHOWERS IN NORTHWEST FLOW. DRY AND SEASONAL LATE WEEK. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... WDSPRD IFR/OCNL LIFR CONDS ARE EXPD TO CONT TDA AS UPR OH VLY LOW PRES BRINGS RAIN TO THE RGN. INCRG NRLY WNDS AND COND IMPROVEMENT TO LOW END MVFR ARE EXPD BY THIS EVE AS THE SFC LOW SHIFTS E AND RAIN TAPERS OFF. OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RSTRNS ARE EXPD MON NGT THRU WED AS LOW PRES BRINGS SNW SHWRS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/07
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1146 PM CST FRI DEC 5 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 218 PM CST FRI DEC 5 2014 THE SHORT TERM FORECAST THROUGH SATURDAY IS RELATIVELY QUIET IN TERMS OF MAJOR WEATHER ISSUES. MILD TEMPERATURES THIS AFTERNOON WILL BE TEMPERED A BIT IN THE WAKE OF FRONTAL BOUNDARY PASSING THROUGH THE FORECAST AREA AT THIS TIME. TEMPERATURES WILL ACTUALLY BE NEAR NORMAL TONIGHT AND SATURDAY...THOUGH IT WILL FEEL QUITE A BIT COOLER TONIGHT WITH UPPER TEENS AND 20S. DECENT MODEL AGREEMENT WITH SOME LOWER CLOUDS TRYING TO SNEAK BACK WEST TONIGHT AND PUSH INTO THE HIGHWAY 81 CORRIDOR AREA TOWARD DAWN SATURDAY AND LINGER INTO THE MORNING. HAVE INCREASED CLOUDS IN THAT AREA...AND ADDED A BIT OF PATCHY FOG FOG WHICH ALIGNS WELL WITH WFOS OMAHA AND TOPEKA FORECAST. SOME CONCERN OF FOG IN THE NORTHWEST PART OF THE FORECAST AREA...WHERE WINDS TURN NEARLY CALM. HRRR HINTS AT LOWER CLOUDS AND VISIBILITY OVER PARTS OF THE SANDHILLS. WILL HOLD OFF FOR NOW BUT WORTH NOTING HEADING INTO TONIGHT. BEYOND THAT...SATURDAY WILL SEE MID/HIGH CLOUDS START TO INCREASE FROM THE WEST IN THE AFTERNOON AS WARM ADVECTION INCREASES AHEAD OF NEXT WEATHER SYSTEM ON SUNDAY. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 218 PM CST FRI DEC 5 2014 GUIDANCE SUGGESTS THE LONG-TERM FORECAST PERIOD WILL START OFF WITH UPPER TROPOSPHERIC RIDGING OVER THE CENTRAL CONUS AND A SUBTLE TROUGH AXIS JUST WEST OF THE ROCKY MOUNTAINS AT 00Z SUNDAY. THIS TROUGH AXIS IS EXPECTED TO SHIFT EAST SATURDAY NIGHT INTO SUNDAY...WITH THIS TROUGH AXIS LIKELY CLEARING OUR AREA DURING THE DAY SUNDAY. NORTHWESTERLY UPPER TROPOSPHERIC FLOW IS THEN EXPECTED TO OVERTAKE THE CENTRAL CONUS THROUGH MUCH OF THE REMAINDER OF THE LONG-TERM FORECAST PERIOD AS UPPER TROPOSPHERIC TROUGHING STRENGTHENS OVER THE EASTERN CONUS AND RIDGING BUILDS ACROSS THE WEST. ALTHOUGH UNCERTAINTY REMAINS...THERE REMAIN HINTS AT A BRIEF PERIOD OF PRECIPITATION PRODUCTION ACROSS THE CENTRAL PLAINS ON SUNDAY AS TROPOSPHERIC MOISTURE AND UPPER TROPOSPHERIC THERMAL ADVECTION INCREASES AHEAD OF THE APPROACHING TROUGH AXIS. QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL CONTINUE TO SUGGEST LIGHT PRECIPITATION WILL BE REALIZED ACROSS PORTIONS OF OUR CWA ON SUNDAY AND AS A RESULT...CONTINUED WITH POPS...ALBEIT LOW...ACROSS MUCH OF THE AREA ON SUNDAY. UNFORTUNATELY PRECIPITATION TYPE REMAINS QUESTIONABLE AS FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST AN ELEVATED WARM LAYER WILL LIKELY PROVIDE LIQUID PRECIPITATION WHILE SURFACE TEMPERATURE READINGS FALL TO NEAR OR BELOW FREEZING AROUND DAYBREAK SUNDAY. PREVIOUS SHIFT WENT AHEAD AND INSERTED A MENTION OF LIGHT FREEZING RAIN FOR A TIME SUNDAY MORNING AND AT THIS TIME...SEE NO REASON TO REMOVE THIS WORDING. GIVEN ALL THIS...A SLIGHT CHANCE FOR LIGHT FREEZING RAIN REMAINS IN THE FORECAST FOR MUCH OF THE AREA FOR A FEW HOURS SUNDAY MORNING AROUND DAYBREAK...WITH LIGHT RAIN THEN FORECAST BY 14Z AS SURFACE TEMPERATURE READINGS CLIMB ABOVE FREEZING. THERE MAY ALSO BE A PERIOD OF LIGHT DRIZZLE OR LIGHT FREEZING DRIZZLE ACROSS PORTIONS OF THE CWA SUNDAY MORNING...WITH GUIDANCE SUGGESTING 0-1KM RELATIVE HUMIDITY VALUES NEAR 100% WILL ACCOMPANY 0- 1KM BULK SHEAR VALUES OF 25-30KTS. GIVEN THE POTENTIAL FOR A SATURATED LOWER TROPOSPHERE AS WELL AS SUFFICIENT TURBULENT MIXING...OPTED TO KEEP A MENTION OF LIGHT DRIZZLE AND LIGHT FREEZING DRIZZLE GOING IN THE FORECAST FOR SUNDAY MORNING. AN OVERALL LACK IN OMEGA SHOULD THEN KEEP US DRY THROUGH MUCH OF THE REST OF THE LONG-TERM FORECAST PERIOD...ALTHOUGH THERE ARE HINTS OF AN UPPER TROPOSPHERIC SHORT WAVE PERHAPS BRINGING A ROUND OF LIGHT PRECIPITATION TO THE REGION ON FRIDAY AND AS A RESULT...WENT WITH A LOW POP ACROSS PORTIONS OF THE CWA ON FRIDAY. LITTLE IF ANY CHANGE IN BOUNDARY-LAYER AIR MASS SHOULD PRESENT SIMILAR TEMPERATURE READINGS FROM DAY TO DAY DURING THE LONG-TERM FORECAST PERIOD...WITH HIGHS IN THE UPPER 40S TO MID 50S AND LOW IN THE UPPER 20S TO LOWER 30S CURRENTLY FORECAST FOR THE MOST PART. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1129 PM CST FRI DEC 5 2014 FOR THE MOST PART...QUIET WEATHER IS EXPECTED DURING THE TAF PERIOD. THAT BEING SAID...THERE IS A CONCERN THAT THE TERMINALS...KGRI IN PARTICULAR...MAY BE ON THE EDGE OF STRATUS WORKING WESTWARD AND IF LOW CLOUDS MAKE IT THIS FAR WEST...THEN FOG MAY OCCUR ON THE EDGE OF THE STRATUS. AGAIN TOWARD THE END OF THE TAF PERIOD...IN RETURN FLOW...LLVL MOISTURE WILL WORK TO THE NORTH AND WEST AGAIN AND WILL NEED TO MONITOR FOR LOW CLOUD AND FOG POTENTIAL. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...NOAA/NWS/MORITZ LONG TERM...BRYANT AVIATION...FAY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1145 PM CST FRI DEC 5 2014 .SYNOPSIS... ISSUED AT 322 PM CST FRI DEC 5 2014 WEAK COLD FRONT STALLING NEAR THE KS/NEB BORDER THIS AFTERNOON. MOSTLY SUNNY SKIES AND SOME 10 TO 15 MPH NORTHERLY WINDS BEHIND THE FRONT HAVE ALLOWED FOR GOOD MIXING WITH TEMPERATURES IN THE UPPER 40S AND 50S. MEANWHILE HIGH PRESSURE IS SETTLING ACROSS THE NORTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 TONIGHT HIGH PRESSURE WILL CONTINUE TO DRIFT ACROSS THE NORTHERN PLAINS. THIS WILL CAUSE THE WINDS TO BECOME EASTERLY/SOUTHEASTERLY. THIS WIND SWITCH WILL HELP TO USHER IN SOME LL MOISTURE. THIS WILL COMBINE WITH MOSTLY CLEAR SKIES AND GOOD RADIATIONAL COOLING TO PRODUCE LOWS IN THE TEENS AND MAYBE SOME PATCHY FOG. SOME CONCERNS TOWARDS THE FOG DEVELOPMENT AS AFTERNOON TEMPS IN THE 50S MIXED THE MOISTURE FAIRLY WELL. ALSO A VERY DRY SURFACE...LITTLE RAIN OVER THE LAST MONTH ACROSS MOST OF THE AREA. THE NAM IS THE ONLY MODEL SUGGESTING DEVELOPMENT...ALTHOUGH IT IS A LITTLE HIGH WITH CURRENT DEW PTS. THE RUC IS LESS FAVORABLE...BUT IS CLOSER BUT IS A DEGREE OR SO TO LOW WITH DEW PTS. THUS THE FORECAST DOES INCLUDE SOME PATCHY FOG IN THE PLATTE RIVER VALLEY...WHICH IS LIKELY THE FIRST PLACE FOR DEVELOPMENT ALTHOUGH CONFIDENCE IS LOW. HAVE ALSO INCLUDED SOME FOG ACROSS THE FAR NORTHWEST...HOWEVER THERE IS BETTER GROUND MOISTURE. TOMORROW COOL HIGH PRESSURE CENTERED OVER MINNESOTA...HOWEVER WILL SEE SOME COOLER TEMPS ALOFT /850 MB TEMPS AROUND 5C/ INTO THE HIGH PLAINS. WILL KEEP TEMPS ABOUT 5 TO 10 DEGREES COOLER THAN TODAY. LATELY THE WARMER MAV HAS BEEN CLOSER TO REALITY AND FAVORED THESE WARMER NUMBERS FOR TOMORROW. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 ...ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS FORECAST SUNDAY THROUGH FRIDAY... MID RANGE PERIODS (SATURDAY NIGHT THROUGH MONDAY)... THE UPPER TROUGH EXITING THE ROCKIES WILL MOVE ACROSS WESTERN NEBRASKA SATURDAY NIGHT INTO SUNDAY. WHILE MOISTURE WILL BE AMPLE FROM H7 TO H5...H85 TO H7 RELATIVELY DRY. CONCERN LIES IN SATURATED LAYER BELOW 875 MB. WITH WEAK OMEGA PRESENT ALONG WITH SUPERCOOLED DROPLETS OF -1C TO -3C...INTRODUCED PATCHY FREEZING FRIZZLE WHICH IS POSSIBLE FROM 09Z TO 15Z SUNDAY. SURFACE TEMPERATURES DURING THIS TIME SHOULD RANGE FROM 28 TO 32 DEGREES. THE AREA MAY AFFECT SOUTHEASTERN AREAS MAINLY EAST OF A CURTIS THROUGH CALLAWAY AND STUART LINE. OTHERWISE CLEARING SKIES FROM WEST TO EAST ON SUNDAY WITH ANOTHER NICE WARMUP. DOWNSLOPING WEST TO NORTHWEST WINDS 5 TO 15 MPH SHOULD PUSH HIGHS UP INTO THE LOWER TO MID 50S...EXCEPT COOLER UPPER 40S NEAR ONEILL AND BARTLETT. A WEAK COLD FRONT SUNDAY NIGHT. HIGHS MONDAY HOWEVER WILL REMAIN VERY SIMILAR TO SUNDAY. EXTENDED PERIODS (MONDAY NIGHT THROUGH FRIDAY)... THE MILD CONDITIONS WILL PERSIST IN THE EXTENDED PERIODS AS UPPER RIDGING DOMINATES THE CENTRAL CONUS. INCREASED TROUGHING ONTO THE WEST COAST WILL ALSO HELP TO AMPLIFY DOWNSTREAM RIDGE. UPPER RIDGING WILL BUILD INTO THE CENTRAL CONUS WEDNESDAY THROUGH FRIDAY WITH HIGHS IN THE 50S. SOME HIGHS IN THE WEST COULD EXCEED 60 DEGREES WEDNESDAY AND BEYOND. BY FRIDAY...A STRONG UPPER TROUGH WILL MOVE ONTO THE WEST COAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1145 PM CST FRI DEC 5 2014 EXPECT MAINLY CLEAR SKIES OVERNIGHT ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. SOME PATCHY FOG IS POSSIBLE IN THE PLATTE RIVER VALLEY TOWARD MORNING. VISBYS AT THE KLBF TERMINAL MAY DROP DOWN TO 3SM AROUND 12Z SATURDAY. DURING THE DAY ON SATURDAY...HIGH CLOUDS WILL BEGIN TO INCREASE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA AS A STORM SYSTEM MOVES INTO THE SOUTHWESTERN UNITED STATES. BROKEN CIGS AROUND 20000 FT AGL ARE LIKELY AROUND 00Z SUNDAY...WITH OVERCAST CIGS AROUND 10000 FT AGL EXPECTED FROM 00Z TO 06Z SUNDAY. WINDS WILL BE FROM THE SOUTH OR SOUTHEAST AT AROUND 10 KTS ON SATURDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MASEK SHORT TERM...MASEK LONG TERM...ROBERG AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1251 AM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE WILL PASS JUST SOUTH OF THE REGION TONIGHT INTO SATURDAY WITH MODERATING TEMPERATURES AND WIDESPREAD LIGHT MIXED PRECIPITATION EXPECTED. COLDER AND DRIER WEATHER RETURNS BEHIND THIS SYSTEM BY SATURDAY NIGHT AND PERSISTS INTO MONDAY AS CANADIAN HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST. BY THE MIDDLE OF NEXT WEEK...THERE IS INCREASING CONFIDENCE THAT A SIGNIFICANT WINTER STORM MAY AFFECT THE REGION WITH MODERATE TO HEAVY RAIN AND SNOW. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... AS OF 1233 AM EST SATURDAY...CURRENT FORECAST LOOKS TO BE ON TRACK WITH ONLY CHANGE BEING TO BLEND IN CURRENT OBSERVATIONS. LIGHT SNOW HAS BEGUN IN NORTHERN AND CENTRAL VT BUT THE STEADIEST AREAS OF LIGHT SNOW HAS BEEN ACROSS SOUTHERN VT INTO ESSEX COUNTY NY. ASSESSMENT OF KENX DUAL-POL DATA AND RAP THERMAL PROGS SUGGEST MELTING LAYER ROUGHLY EXTENDS FROM NORTHWEST MA UP TO THE NORTH SIDE OF THE ALBANY METRO THEN EASTWARD ALONG I-90. SO STILL SOME TIME FOR SNOW TO ACCUMULATE FURTHER BEFORE AFOREMENTIONED WARM NOSE LIFTS NORTH AND PRECIPITATION BECOMES MORE OF A MIX OF SNOW...SLEET AND FREEZING RAIN. THIS IS ALREADY CAPTURED WELL IN GOING FORECAST SO NO CHANGES TO THE WINTER WEATHER ADVISORY AT THIS TIME. PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 1020 PM EST FRIDAY FOLLOWS... LIGHT PRECIPITATION IS RATHER WIDESPREAD ACROSS VERMONT THIS EVENING. PRECIPITATION IS MOSTLY IN THE FORM OF SNOW...WITH A FEW POCKETS OF FREEZING RAIN/FREEZING DRIZZLE. ACROSS NORTHERN NEW YORK...SPOTTY COVERAGE OF PRECIPITATION WITH SOME AREAS OF LIGHT SNOW OR MIXED PRECIPITATION. NO SIGNIFICANT CHANGES TO GOING FORECAST...JUST A FEW ADJUSTMENTS TO POPS AND WEATHER OVER NEXT FEW HOURS TO REFLECT LATEST CONDITIONS AND TRENDS. THERMAL PROFILES STILL INDICATE LIGHT SNOW TURNS TO A WINTRY MIX OVERNIGHT...AND TO RAIN IN SOME AREAS. HIGHEST POPS FOR THE OVERNIGHT PERIOD ACROSS CENTRAL AND SOUTHERN SECTIONS OF VERMONT WITH LOWEST POPS ACROSS SAINT LAWRENCE VALLEY. GOING FORECAST HAS ALL OF THIS WELL COVERED. ALSO...NO CHANGES TO WINTER WEATHER ADVISORIES WHICH ARE IN EFFECT FOR MUCH OF VERMONT OUTSIDE OF CHAMPLAIN VALLEY AND PART OF ESSEX COUNTY NY. LOOK FOR A FEW INCHES OF SNOW WITH LIGHT ICE ACCUMULATION. EARLIER DISCUSSION... FORECAST REMAINS MORE OR LESS ON TRACK FOR TONIGHT AS CLOUDS CONTINUE TO THICKEN AND LOWER AS DEEP WARM THERMAL ADVECTION OVERSPREADS THE REGION FROM THE SOUTH AND WEST. PRECIPITATION SEEN ON RADAR LATE THIS AFTERNOON ACROSS EASTERN PORTIONS OF NY STATE IS MAINLY IN VIRGA FORM...BUT STEADIER LIGHT PRECIPITATION STILL ON TRACK TO ARRIVE LATER THIS EVENING/TONIGHT AS LEAD SURFACE WAVE TRACKS ENE FROM THE OHIO VALLEY. LEANED TOWARD GFS THERMAL PROFILES AS NAM SHOWING ITS TYPICAL COLDER BIAS ALOFT. LATEST CAM TRENDS ALSO SUGGEST BULK OF STEADIER PRECIPITATION TO AFFECT AREAS GENERALLY ALONG AND SOUTH OF A KART- KSLK-KBTV-K1V4 LINE LATER TONIGHT WITH FAR NORTHERN COUNTIES SEEING ONLY SCT LIGHT PRECIPITATION AT BEST. THAT SAID...I`M STILL EXPECTING A PERIOD OF SHSN/LIGHT SNOWS TO OVERSPREAD A GOOD PORTION OF THE AREA LATER THIS EVENING/TONIGHT BEFORE PRECIPITATION TRANSITIONS TO A MIX OF PL/FZRA...ESP ACROSS EASTERN PORTIONS OF VT SOUTH OF ROUTE 2 OR SO. ELSEWHERE...ESP IN THE CHAMPLAIN VALLEY AND ADIRONDACKS...MIX WITH PL/FZRA SHOULD BE RELATIVELY BRIEF BEFORE TRANSITION TO LIGHT RAIN GIVEN SOUTHERLY FLOW WILL CONTINUE TO WARM THE NEAR SFC LAYERS. THUS MORE MINIMAL IMPACTS IN THESE LOCATIONS DESPITE ROADS POSSIBLY BEING A LITTLE SLICK BY MORNING. TEMPERATURES TO REMAIN STEADY OR SLOWLY RISE OVERNIGHT...MOST PRONOUNCED FROM THE WESTERN SLOPES WEST ACROSS THE CHAMPLAIN VALLEY INTO OUR NRN NY COUNTIES. SNOWFALL AMOUNTS BY SATURDAY MORNING GENERALLY A DUSTING TO 2 INCHES CHAMPLAIN VALLEY...A GOOD PORTION OF THE NRN ADIRONDACKS AND SAINT LAWRENCE VALLEY. IN CURRENT WINTER WEATHER ADVISORY AREA...1-3 INCHES OF SNOW EXPECTED ACROSS THE HIGH PEAKS REGION AND MUCH OF VERMONT EAST OF THE GREENS WHERE THERMAL PROFILES WILL BE SLIGHTLY COLDER. LOCALIZED HIGHER AMOUNTS...2-4 INCHES OR SO POSSIBLE ACROSS PORTIONS OF NC/NE VT. AGAIN...SOME LIGHT TO TRACE AMOUNTS OF ICE WILL ALSO BE POSSIBLE IN THESE AREAS && .SHORT TERM /7 AM THIS MORNING THROUGH SUNDAY NIGHT/... AS OF 326 PM EST FRIDAY...BY TOMORROW WIDESPREAD LIGHT TO MODERATE PRECIPITATION CONTINUES AS SECONDARY AND MORE ROBUST SFC WAVE RIDES ACROSS THE NORTHERN MID-ATLANTIC INTO SOUTHERN NEW ENGLAND. THERMAL PROFILES CONTINUE TO SLOWLY WARM SUCH THAT MOST AREAS EXCEPT THE FAR NORTH/NORTHWEST SHOULD FULLY TRANSITION TO LIGHT RAIN BY MID TO LATE MORNING WITH PERHAPS A FEW POCKETS OF LIGHT FZRA LINGERING ACROSS SHELTERED ERN VT HOLLOWS THROUGH NOON OR SO. MODELS FAIRLY CONSISTENT IN SHOWING A RATHER SHARP CUTOFF IN STEADIER PRECIPITATION NORTH AND WEST OF A KSLK-KBTV-KNPT LINE TOMORROW. SO AREAS ACROSS FAR NW VT INTO FAR NRN NY/SAINT LAWRENCE VALLEY STEADIER PRECIPITATION LESS LIKELY. BY LATER IN THE AFTERNOON INTO EARLY EVENING THE APPROACH OF A MODESTLY STRONG NORTHERN STREAM UPPER TROUGH WILL PUSH A COLD FRONT THROUGH THE REGION WITH STEADIER PRECIPITATION EXITING SOUTH AND EAST OVER TIME. AS POST-FRONTAL FLOW TRENDS NORTH/NORTHWESTERLY...PRECIPITATION SHOULD TRANSITION BACK TO A PERIOD OF LIGHT SNOW/SHSN FOR A FEW HOURS BEFORE ENDING AS DRIER AIR FILTERS INTO THE REGION. THUS AN ADDITIONAL BACKSIDE D-2" SNOWFALL WILL BE POSSIBLE IN THE 21-03Z TIME FRAME. THEREAFTER...COLD FRONT EXITS SOUTHEAST OVERNIGHT SATURDAY AS ANOMALOUSLY STRONG 1045 MB CANADIAN POLAR HIGH BUILDS ACROSS THE REGION BY SUNDAY/SUNDAY NIGHT ON DIMINISHING NORTHWESTERLY FLOW. THUS THE IDEA OF GRADUAL CLEARING FROM NORTHWEST TO SOUTHEAST SATURDAY EVENING LOOKS ON TRACK AS TEMPERATURES TREND BACK TOWARD SEASONALLY COLD VALUES. INDEED...AS HIGH CRESTS ATOP THE REGION SUNDAY NIGHT WIDESPREAD VALUES IN THE SINGLE DIGITS ABOVE/BELOW ZERO LOOK QUITE REALISTIC AS LIGHT WINDS/CLEAR SKIES LEAD TO OPTIMAL LONGWAVE RADIATIVE PROCESSES. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 326 PM EST FRIDAY...DRY WEATHER IS EXPECTED THROUGH MONDAY NIGHT AS A DOME OF HIGH PRESSURE CONTINUES BUILDING INTO THE AREA. BY TUESDAY MORNING THE UPPER LEVEL TROUGH WILL DIG INTO THE GREAT LAKES AND PUSH THE HIGH PRESSURE WELL OFF TO THE NORTHEAST OVER NEWFOUNDLAND OPENING THE REGION UP FOR A EITHER A COASTAL LOW OR A SHORTWAVE WITH THE UPPER LEVEL TROUGH DEPENDING ON THE MODEL TO PUSH INTO THE REGION. RIGHT NOW THE GFS IS THE LONE LONG RANGE MODEL WITH THE SHORT WAVE SOLUTION. THE ECMWF IS MUCH MORE ALIGNED WITH THE UKMET, CANADIAN AND DGEX IN BRINGING IN A COASTAL LOW UP THE EAST COAST THEN PHASING JUST OFF THE COAST OF NEW JERSEY. AS THE PHASING OCCURS THERE IS AN INCREASING CHANCE OF RAIN/SNOW SHOWER ON WEDNESDAY. THE OCCLUDED LOW REDEVELOPS JUST OFF OF CAPE COD WHICH COULD BRING THE PORTIONS OF THE AREA HEAVY SNOWFALL AS THE WINDS SHIFT AROUND AND DEVELOP A MORE NORTHERLY COMPONENT. WITH HIGH PRESSURE TO THE NORTHWEST NEAR LAKE SUPERIOR A STRONG PRESSURE GRADIENT WILL BRING STRONG NORTHEASTERLY WINDS ON WEDNESDAY SHIFTING TO NORTHERLY BY THURSDAY. RIGHT NOW THE FORECAST IS A BLEND OF THE MODELS WITH LIKELY RAIN/SNOW SHOWERS ON TUESDAY WITH A CHANCE OF SNOW SHOWERS ON THURSDAY AS WE GET HIT BY THE BACK SIDE OF THE LOW. MAX TEMPS WILL BE FOR THE MOST PART NEAR NORMAL WITH MIN TEMPS RUNNING A FEW DEGREES ABOVE NORMAL. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... THROUGH 06Z SUNDAY...MVFR/VFR CEILINGS AND VISIBILITIES WILL CONTINUE EARLY THIS MORNING AS FIRST AREA OF PRECIPITATION MOVES ACROSS THE AREA. THE PRECIPITATION WILL GENERALLY BE LIGHT...BUT WILL BE A MIX OF SNOW...SLEET...AND FREEZING DRIZZLE. THE PRECIPITATION SHOULD END BY 12Z...THEN A SECONDARY AREA OF PRECIPITATION WILL MOVE UP FROM THE OHIO VALLEY AND BE IN THE FORM OF RAIN AND SOME SNOW FROM MID-MORNING THROUGH EARLY EVENING. IT WILL BE DURING THIS PERIOD THAT CEILINGS AND VISIBILITIES WILL LOWER INTO THE MVFR AND IFR CATEGORIES. THE WINDS WILL BECOME NORTHWEST BETWEEN 18Z AND 20Z AND THE PRECIPITATION WILL GRADUALLY COME TO AN END BETWEEN 20Z AND 02Z. VISIBILITIES WILL IMPROVE INTO THE VFR CATEGORY AT THIS TIME...BUT CEILINGS WILL REMAIN MVFR/IFR FOR THE REMAINDER OF THE PERIOD. OUTLOOK 06Z SUNDAY THROUGH WEDNESDAY... 06Z SUN - 12Z TUES: VFR...THOUGH A CHANCE OF MVFR DEVELOPING DURING THE DAY MONDAY. 12Z TUES - 00Z THURS: MVFR EXPECTED WITH PERIODS OF IFR AS A SYSTEM DEVELOPS AND BRINGS PERIODS OF PRECIPITATION. && .MARINE... A LAKE WIND ADVISORY IS IN EFFECT FOR TONIGHT. LOW LEVEL SOUTHERLY JET OVER THE REGION OVERNIGHT...SO EXPECT SOUTH WINDS 15 TO 25 KTS. WAVE HEIGHTS WILL RANGE FROM 2 TO 4 FEET ON THE BROAD LAKE. WINDS ARE EXPECTED TO DROP BELOW ADVISORY CRITERIA SATURDAY MORNING AND THEN SHIFT INTO THE NORTH SATURDAY AFTERNOON WITH THE PASSAGE OF A COLD FRONT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VTZ003- 004-006>008-010>012-016>019. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ034. && $$ SYNOPSIS...JMG NEAR TERM...RJS/LOCONTO SHORT TERM...JMG LONG TERM...DEAL AVIATION...EVENSON/DEAL MARINE...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1234 AM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE WILL PASS JUST SOUTH OF THE REGION TONIGHT INTO SATURDAY WITH MODERATING TEMPERATURES AND WIDESPREAD LIGHT MIXED PRECIPITATION EXPECTED. COLDER AND DRIER WEATHER RETURNS BEHIND THIS SYSTEM BY SATURDAY NIGHT AND PERSISTS INTO MONDAY AS CANADIAN HIGH PRESSURE BRIDGES ACROSS THE NORTHEAST. BY THE MIDDLE OF NEXT WEEK...THERE IS INCREASING CONFIDENCE THAT A SIGNIFICANT WINTER STORM MAY AFFECT THE REGION WITH MODERATE TO HEAVY RAIN AND SNOW. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... AS OF 1233 AM EST SATURDAY...CURRENT FORECAST LOOKS TO BE ON TRACK WITH ONLY CHANGE BEING TO BLEND IN CURRENT OBSERVATIONS. LIGHT SNOW HAS BEGUN IN NORTHERN AND CENTRAL VT BUT THE STEADIEST AREAS OF LIGHT SNOW HAS BEEN ACROSS SOUTHERN VT INTO ESSEX COUNTY NY. ASSESSMENT OF KENX DUAL-POL DATA AND RAP THERMAL PROGS SUGGEST MELTING LAYER ROUGHLY EXTENDS FROM NORTHWEST MA UP TO THE NORTH SIDE OF THE ALBANY METRO THEN EASTWARD ALONG I-90. SO STILL SOME TIME FOR SNOW TO ACCUMULATE FURTHER BEFORE AFOREMENTIONED WARM NOSE LIFTS NORTH AND PRECIPITATION BECOMES MORE OF A MIX OF SNOW...SLEET AND FREEZING RAIN. THIS IS ALREADY CAPTURED WELL IN GOING FORECAST SO NO CHANGES TO THE WINTER WEATHER ADVISORY AT THIS TIME. PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 1020 PM EST FRIDAY FOLLOWS... LIGHT PRECIPITATION IS RATHER WIDESPREAD ACROSS VERMONT THIS EVENING. PRECIP IS MOSTLY IN THE FORM OF SNOW...WITH A FEW POCKETS OF FREEZING RAIN/FREEZING DRIZZLE. ACROSS NORTHERN NEW YORK...SPOTTY COVERAGE OF PRECIPITATION WITH SOME AREAS OF LIGHT SNOW OR MIXED PRECIP. NO SIGNIFICANT CHANGES TO GOING FORECAST...JUST A FEW ADJUSTMENTS TO POPS AND WX OVER NEXT FEW HOURS TO REFLECT LATEST CONDITIONS AND TRENDS. THERMAL PROFILES STILL INDICATE LIGHT SNOW TURNS TO A WINTRY MIX OVERNIGHT...AND TO RAIN IN SOME AREAS. HIGHEST POPS FOR THE OVERNIGHT PERIOD ACROSS CENTRAL AND SOUTHERN SECTIONS OF VERMONT WITH LOWEST POPS ACROSS SAINT LAWRENCE VALLEY. GOING FORECAST HAS ALL OF THIS WELL COVERED. ALSO...NO CHANGES TO WINTER WEATHER ADVISORIES WHICH ARE IN EFFECT FOR MUCH OF VERMONT OUTSIDE OF CHAMPLAIN VALLEY AND PART OF ESSEX COUNTY NY. LOOK FOR A FEW INCHES OF SNOW WITH LIGHT ICE ACCUMULATION. EARLIER DISCUSSION... FORECAST REMAINS MORE OR LESS ON TRACK FOR TONIGHT AS CLOUDS CONTINUE TO THICKEN AND LOWER AS DEEP WARM THERMAL ADVECTION OVERSPREADS THE REGION FROM THE SOUTH AND WEST. PRECIPITATION SEEN ON RADAR LATE THIS AFTERNOON ACROSS EASTERN PORTIONS OF NY STATE IS MAINLY IN VIRGA FORM...BUT STEADIER LIGHT PCPN STILL ON TRACK TO ARRIVE LATER THIS EVENING/TONIGHT AS LEAD SURFACE WAVE TRACKS ENE FROM THE OHIO VALLEY. LEANED TOWARD GFS THERMAL PROFILES AS NAM SHOWING ITS TYPICAL COLDER BIAS ALOFT. LATEST CAM TRENDS ALSO SUGGEST BULK OF STEADIER PCPN TO AFFECT AREAS GENERALLY ALONG AND SOUTH OF A KART- KSLK-KBTV-K1V4 LINE LATER TONIGHT WITH FAR NORTHERN COUNTIES SEEING ONLY SCT LIGHT PCPN AT BEST. THAT SAID...I`M STILL EXPECTING A PERIOD OF SHSN/LIGHT SNOWS TO OVERSPREAD A GOOD PORTION OF THE AREA LATER THIS EVENING/TONIGHT BEFORE PCPN TRANSITIONS TO A MIX OF PL/FZRA...ESP ACROSS EASTERN PORTIONS OF VT SOUTH OF ROUTE 2 OR SO. ELSEWHERE...ESP IN THE CHAMPLAIN VALLEY AND DACKS...MIX WITH PL/FZRA SHOULD BE RELATIVELY BRIEF BEFORE TRANSITION TO LIGHT RAIN GIVEN SOUTHERLY FLOW WILL CONTINUE TO WARM THE NEAR SFC LAYERS. THUS MORE MINIMAL IMPACTS IN THESE LOCATIONS DESPITE ROADS POSSIBLY BEING A LITTLE SLICK BY MORNING. TEMPERATURES TO REMAIN STEADY OR SLOWLY RISE OVERNIGHT...MOST PRONOUNCED FROM THE WESTERN SLOPES WEST ACROSS THE CHAMPLAIN VALLEY INTO OUR NRN NY COUNTIES. SNOWFALL AMOUNTS BY SATURDAY MORNING GENERALLY A DUSTING TO 2 INCHES CHAMPLAIN VALLEY...A GOOD PORTION OF THE NRN DACKS AND SLV. IN CURRENT WINTER WX ADVISORY AREA...1-3 INCHES OF SNOW EXPECTED ACROSS THE HIGH PEAKS REGION AND MUCH OF VERMONT EAST OF THE GREENS WHERE THERMAL PROFILES WILL BE SLIGHTLY COLDER. LOCALIZED HIGHER AMOUNTS...2-4 INCHES OR SO POSSIBLE ACROSS PORTIONS OF NC/NE VT. AGAIN...SOME LIGHT TO TRACE AMOUNTS OF ICE WILL ALSO BE POSSIBLE IN THESE AREAS && .SHORT TERM /7 AM THIS MORNING THROUGH SUNDAY NIGHT/... AS OF 326 PM EST FRIDAY...BY TOMORROW WIDESPREAD LIGHT TO MODERATE PRECIPITATION CONTINUES AS SECONDARY AND MORE ROBUST SFC WAVE RIDES ACROSS THE NORTHERN MID-ATLANTIC INTO SOUTHERN NEW ENGLAND. THERMAL PROFILES CONTINUE TO SLOWLY WARM SUCH THAT MOST AREAS EXCEPT THE FAR NORTH/NORTHWEST SHOULD FULLY TRANSITION TO LIGHT RAIN BY MID TO LATE MORNING WITH PERHAPS A FEW POCKETS OF LIGHT FZRA LINGERING ACROSS SHELTERED ERN VT HOLLOWS THROUGH NOON OR SO. MODELS FAIRLY CONSISTENT IN SHOWING A RATHER SHARP CUTOFF IN STEADIER PCPN NORTH AND WEST OF A KSLK-KBTV-KNPT LINE TOMORROW. SO AREAS ACROSS FAR NW VT INTO FAR NRN NY/SLV STEADIER PCPN LESS LIKELY. BY LATER IN THE AFTERNOON INTO EARLY EVENING THE APPROACH OF A MODESTLY STRONG NORTHERN STREAM UPPER TROUGH WILL PUSH A COLD FRONT THROUGH THE REGION WITH STEADIER PCPN EXITING SOUTH AND EAST OVER TIME. AS POST-FRONTAL FLOW TRENDS NORTH/NORTHWESTERLY...PCPN SHOULD TRANSITION BACK TO A PERIOD OF LIGHT SNOW/SHSN FOR A FEW HOURS BEFORE ENDING AS DRIER AIR FILTERS INTO THE REGION. THUS AN ADDITIONAL BACKSIDE D-2" SNOWFALL WILL BE POSSIBLE IN THE 21-03Z TIME FRAME. THEREAFTER...COLD FRONT EXITS SOUTHEAST OVERNIGHT SATURDAY AS ANOMALOUSLY STRONG 1045 MB CANADIAN POLAR HIGH BUILDS ACROSS THE REGION BY SUNDAY/SUNDAY NIGHT ON DIMINISHING NORTHWESTERLY FLOW. THUS THE IDEA OF GRADUAL CLEARING FROM NORTHWEST TO SOUTHEAST SATURDAY EVENING LOOKS ON TRACK AS TEMPERATURES TREND BACK TOWARD SEASONALLY COLD VALUES. INDEED...AS HIGH CRESTS ATOP THE REGION SUNDAY NIGHT WIDESPREAD VALUES IN THE SINGLE DIGITS ABOVE/BELOW ZERO LOOK QUITE REALISTIC AS LIGHT WINDS/CLR SKIES LEAD TO OPTIMAL LONGWAVE RADIATIVE PROCESSES. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 326 PM EST FRIDAY...DRY WEATHER IS EXPECTED THROUGH MONDAY NIGHT AS A DOME OF HIGH PRESSURE CONTINUES BUILDING INTO THE AREA. BY TUESDAY MORNING THE UPPER LEVEL TROUGH WILL DIG INTO THE GREAT LAKES AND PUSH THE HIGH PRESSURE WELL OFF TO THE NORTHEAST OVER NEWFOUNDLAND OPENING THE REGION UP FOR A EITHER A COASTAL LOW OR A SHORTWAVE WITH THE UPPER LEVEL TROUGH DEPENDING ON THE MODEL TO PUSH INTO THE REGION. RIGHT NOW THE GFS IS THE LONE LONG RANGE MODEL WITH THE SHORT WAVE SOLUTION. THE ECMWF IS MUCH MORE ALIGNED WITH THE UKMET, CANADIAN AND DGEX IN BRINGING IN A COASTAL LOW UP THE EAST COAST THEN PHASING JUST OFF THE COAST OF NEW JERSEY. AS THE PHASING OCCURS THERE IS AN INCREASING CHANCE OF RAIN/SNOW SHOWER ON WEDNESDAY. THE OCCLUDED LOW REDEVELOPS JUST OFF OF CAPE COD WHICH COULD BRING THE PORTIONS OF THE AREA HEAVY SNOWFALL AS THE WINDS SHIFT AROUND AND DEVELOP A MORE NORTHERLY COMPONENT. WITH HIGH PRESSURE TO THE NORTHWEST NEAR LAKE SUPERIOR A STRONG PRESSURE GRADIENT WILL BRING STRONG NORTHEASTERLY WINDS ON WEDNESDAY SHIFTING TO NORTHERLY BY THURSDAY. RIGHT NOW THE FORECAST IS A BLEND OF THE MODELS WITH LIKELY RAIN/SNOW SHOWERS ON TUESDAY WITH A CHANCE OF SNOW SHOWERS ON THURSDAY AS WE GET HIT BY THE BACK SIDE OF THE LOW. MAX TEMPS WILL BE FOR THE MOST PART NEAR NORMAL WITH MIN TEMPS RUNNING A FEW DEGREES ABOVE NORMAL. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... THROUGH 00Z SUNDAY...A GENERAL DETERIORATION OF FLIGHT CONDITIONS IS EXPECTED OVER THE NEXT 24 HOURS. ALL SITES START VFR THIS EVENING WITH A FEW BRIEF REDUCTIONS TO MVFR IN LIGHT SNOW SHOWERS/FLURRIES FOR THE FIRST COUPLE OF HOURS. AFTERWARD...CEILINGS WILL LOWER TO MVFR AREA-WIDE AND AREAS OF LIGHT MIXED PRECIPITATION WILL CONTINUE TO DEVELOP AND BRING PERIODS OF REDUCED VISIBILITIES (MAINLY TO MVFR ALTHOUGH SOME IFR POSSIBLE AT SLK). MOST SITES WILL CHANGE TO RAIN LATE TONIGHT/EARLY SATURDAY MORNING. SOUTHERLY FLOW TONIGHT (EXCEPT NORTHEAST AT MSS) WILL TURN NORTH/NORTHWESTERLY BY SATURDAY AFTERNOON USHERING IN AN ADDITIONAL LOWERING OF CEILINGS AND A CHANGE BACK OVER TO SNOW...THUS EXPECTING WIDESPREAD MVFR/IFR BY LATE SATURDAY. OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY... 00Z SUN - 06Z SUN: MVFR/IFR IN LIGHT SNOW...GRADUALLY ENDING FROM WEST TO EAST. 06Z SUN - 12Z TUES: VFR...THOUGH A CHANCE OF MVFR DEVELOPING DURING THE DAY MONDAY. 12Z TUES - 00Z THURS: MVFR EXPECTED WITH PERIODS OF IFR AS A SYSTEM DEVELOPS AND BRINGS PERIODS OF PRECIPITATION. && .MARINE... A LAKE WIND ADVISORY IS IN EFFECT FOR TONIGHT. LOW LEVEL SOUTHERLY JET OVER THE REGION OVERNIGHT...SO EXPECT SOUTH WINDS 15 TO 25 KTS. WAVE HEIGHTS WILL RANGE FROM 2 TO 4 FEET ON THE BROAD LAKE. WINDS ARE EXPECTED TO DROP BELOW ADVISORY CRITERIA SATURDAY MORNING AND THEN SHIFT INTO THE NORTH SATURDAY AFTERNOON WITH THE PASSAGE OF A COLD FRONT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VTZ003- 004-006>008-010>012-016>019. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ034. && $$ SYNOPSIS...JMG NEAR TERM...RJS/LOCONTO SHORT TERM...JMG LONG TERM...DEAL AVIATION...DEAL/MUCCILLI MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
425 AM EST SAT DEC 6 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE CAROLINAS BRINGING SHOWERS TODAY AND ISOLATED THUNDERSTORMS TONIGHT BEFORE REACHING OFF SHORE OVERNIGHT. A STRONG WEDGE OF HIGH PRESSURE WILL BUILD SOUTH SUNDAY AND MONDAY...BRINGING GUSTY NORTH WINDS AND MUCH COOLER TEMPERATURES. CANADIAN HIGH PRESSURE NEXT WEEK WILL MAINTAIN SEASONABLY COOL TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 4 AM SATURDAY...SURFACE LOW PRECEDING AN UPPER TROUGH WAS APPROACHING THE CENTRAL APPALACHIANS...HELPING TO LIFT A COASTAL TROUGH ONTO THE CAROLINA COAST EARLY THIS MORNING. KLTX SENSING MODERATE CONVECTION OFFSHORE OF CAPE FEAR MOVING NORTH TOWARD SURF CITY TO CARTERET COUNTY TO CAPE LOOKOUT. ORGANIZED PRECIPITATION WAS ADVANCING INTO THE WESTERN CAROLINAS. THE TRENDING WEATHER FEATURES OCEAN CONVECTION MOVING N AND NE OF NE SC/SE NC THROUGH MORNING WHILE A BROADER SHIELD OF -RA ENCROACHES FROM THE WEST. A COLD FRONT WILL SWEEP OFF THE COAST LATE THIS EVENING. AHEAD OF THE FRONT DESTABILIZATION MAY STRENGTHEN IN THE AFTERNOON IF CLOUD BREAKS ALLOW SURFACE WARMING...OTHERWISE BEST MIXED LAYER CAPES SPIKE AS DOES OMEGA AND COLUMN MOISTURE OVER THE AREA BETWEEN 00Z-04Z. LOW-LEVELS WIND DO NOT APPEAR TO SUPPORT A SEVERE THREAT AHEAD OF THE FRONT BUT WILL MAINTAIN ISOLATED TSTM MENTION. MAXIMUM TEMPERATURES WILL NOT BE EASY SINCE BREAKS IN THE CLOUDS COULD WARM LOCAL TEMPS QUICKLY IN THE GROWING WARM SECTOR. BREAKS HOWEVER SHOULD NOT LAST LONG WITH PLENTIFUL UPSTREAM CLOUDS NOTED CURRENTLY...UPPER 60S TO LOWER 70S MOST PLACES AND A LITTLE COOLER BY THE SEA. COLD AIR ADVECTION ALREADY UNDERWAY PRIOR TO DAYBREAK IN BRISK AND DEEP NORTH WIND FLOW...AND GUSTY. MINIMUMS BY FIRST LIGHT SUNDAY IN THE 40S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STRONG HIGH PRESSURE WILL BUILD DOWN ACROSS THE CAROLINAS ON SUNDAY. A 1045 MB HIGH WILL MOVE ACROSS CANADA FROM JUST NORTH OF THE GREAT LAKES TO THE CANADIAN MARITIMES BY MONDAY. TIGHTENED GRADIENT FLOW WILL EXIST BETWEEN THIS AREA OF HIGH PRESSURE AND LOW PRESSURE LINGERING OVER THE DISTANT OFF SHORE WATERS OF THE CAROLINAS. EXPECT GUSTY NORTHERLY WINDS WINDS THROUGH MUCH OF THE PERIOD. SHOULD SEE SOME CLEARING OUT ON SUNDAY IN DRY NORTHERLY FLOW ESPECIALLY THROUGH INLAND AREAS ALTHOUGH STRONG INVERSION COULD LOCK IN A DECENT LAYER OF MOISTURE UNDERNEATH. CAA WILL BRING 850 TEMPS DOWN SEVERAL DEGREES THROUGH SUNDAY INTO EARLY MONDAY. COASTAL AREAS MAY BE THE LAST PLACE TO SEE SOME SUNSHINE ON SUNDAY AFTN. PCP WATER VALUES DROP DOWN NEAR A QUARTER OF AN INCH INLAND WEST OF I95 BUT CLOSE TO THE COAST VALUES REMAIN AROUND A HALF INCH UNTIL LATER ON SUNDAY. OVERALL EXPECT TO SEE SOME SUNSHINE BY SUNDAY AFTERNOON WITH TEMPS IN THE 50S. MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES ON MONDAY PUSHING NEXT NORTHERN STREAM SYSTEM EAST. THIS WILL PUSH THE HIGH PRESSURE OFF THE COAST OF THE CANADIAN MARITIMES LEAVING A WEDGE OF HIGH PRESSURE DOWN THROUGH THE INLAND CAROLINAS. AT THE SAME TIME LOW PRESSURE OFF SHORE WILL RETROGRADE BACK WEST TOWARD THE CAROLINA COAST BEFORE LIFTING OFF TO THE NORTH MON NIGHT. THE LOW LEVEL INVERSION WILL STRENGTHEN FURTHER AS WARMER AND MOISTER FLOW DEVELOPS IN THE LOW LEVELS. EXPECT LOW CLOUDS AND CONTINUED COOL CONDITIONS WITH GUSTY NORTHERLY WINDS AND TEMPS IN THE 50S ONCE AGAIN. MOST PCP SHOULD REMAIN OFF THE COAST BUT MAY SEE SOME WORK ITS WAY INLAND THROUGH THE DAY AS LOW MOVES UP ALONG THE CAROLINA COAST TOWARD VA. BY MON NIGHT DIGGING MID TO UPPER TROUGH WILL PUSH COLD FRONT EAST WHILE LOW PRESSURE LIFTS OFF TO THE NORTH. THIS WILL SQUEEZE OUT ANY REMAINING WEDGE BY EARLY TUES. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY...DEEP MID TO UPPER TROUGH WILL PUSH NORTHERN STREAM SYSTEM EAST AS LOW PRESSURE SYSTEM LIFTS NORTHEAST AWAY FROM THE CAROLINAS UP ALONG THE EASTERN SEABOARD. ONCE THIS SYSTEM SHIFTS OFF SHORE BY LATE TUES IT WILL DRY OUT THE COLUMN IN DEEP NW FLOW. ALL THE RESIDUAL LOW LEVEL MOISTURE WILL DIMINISH WITH DEEP DRY COLUMN IN PLACE BY WED THROUGH FRI. OVERALL EXPECT CLEARING SKIES ON TUES WITH STRONG DRY HIGH PRESSURE BUILDING IN. A REINFORCING SHOT OF COLD AIR WITH 850 TEMPS DROPPING DOWN BELOW 0C WILL KEEP COOL TEMPS THROUGH MID WEEK. EXPECT HIGHS IN THE 50S MOST DAYS WITH WED BEING THE COOLEST DAY. SHOULD SEE PLENTY OF SUNSHINE WED AND THURS. HIGH PRESSURE WILL MOVE CLOSER OVERHEAD BY THURS INTO FRI WITH WEAK GRADIENT MAINTAINING LIGHT WINDS ALLOWING AIR MASS TO MODIFY AND BECOME SLIGHTLY WARMER. A SHORTWAVE IN THE MID LEVELS WILL PASS THROUGH THURS NIGHT INTO FRI WHICH SHOULD GIVE US SOME PASSING HIGHER CLOUDS. WILL KEEP POPS OUT OF FORECAST FOR NOW. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RATHER LOW CONFIDENCE ON THE BACK END OF THE FORECAST PERIOD WITH RESPECT TO CEILINGS AND THE TIMING OF PRECIP. LOOKS LIKE THERE COULD BE TWO BATCHES OF RAIN/SHOWERS: THE FIRST AROUND SUNRISE WITH A COASTAL TROUGH...THEN ANOTHER ROUND IN THE LATE AFTERNOON AHEAD OF A COLD FRONT. MODELS ARE IN REASONABLE AGREEMENT INTRODUCING IFR STRATUS/FOG AROUND DAYBREAK IF NOT BEFORE...AND THIS MAKES SENSE GIVEN THE WEAK WARM AIR ADVECTION. THE HRRR MODEL THINKS THAT ILM STANDS THE BEST CHANCE FOR MORNING PRECIP...BUT THE MYRTLES COULD ALSO GET INTO THE ACT. THINK THE MORNING PRECIP WILL GIVE WAY TO MVFR CEILINGS AND SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT WHICH WILL ARRIVE AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PERIODS OF MVFR/IFR CIGS ARE LIKELY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GUSTY NORTH WINDS SUN/MON BEHIND THE COLD FRONT. BECOMING VFR DURING TUE. VFR WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 4 AM SATURDAY...WINDS AHEAD OF A COLD FRONT WILL REMAIN RELATIVELY LIGHT TODAY...INCREASING MORE SHARPLY INTO EARLY SUNDAY AS COLD AIR SPILLS ACROSS THE WATERS. ADVISORY SC WATERS AND GALE WATCH NC TO BEGINS 11Z SUNDAY WITH THIS ISSUANCE. PRESENTLY NNE WIND 10 KT AT MASONBORO BUOY AND SE 15G17KT FRYING PAN ILLUSTRATES WELL THE COASTAL TROUGH BOUNDARY. WILL HAVE TO WATCH FOR ADVISORY CONDITIONS EARLIER THAN PLANNED SINCE 41013 ALREADY APPROACHING 6 FT. ISOLATED TSTMS POSSIBLE TONIGHT ON THE 0-20 NM WATERS JUST AHEAD OF THE COLD FRONT. BY DAYBREAK SUNDAY EXPECT 30 KT GUSTS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...GALE WATCH REMAINS IN EFFECT FOR THE NC WATERS BEGINNING SUNDAY MORNING WITH A SMALL CRAFT ADVISORY OVER SOUTH CAROLINA WATERS AS WINDS INCREASE THROUGH SUN INTO SUN NIGHT 20 TO 30 KTS WITH FREQUENT GUSTS TO 35 KTS OR GREATER AS STRONG HIGH PRESSURE BUILDS DOWN INTO THE CAROLINAS. THIS TIGHTENED GRADIENT FLOW WILL CONTINUE INTO MONDAY AS WEDGE STRENGTHENS DOWN THROUGH INLAND CAROLINAS WHILE LOW PRESSURE LINGERS AND SHIFTS CLOSER TO THE COAST BEFORE LIFTING OFF TO THE NORTH BY EARLY TUES. THIS WILL MAINTAIN STRONG NORTHERLY WINDS AND HIGH SEAS. SEAS WILL RAMP UP SUN MORNING ABOVE SCA THRESHOLDS AND PEAKING CLOSE TO 10 FT IN OUTER WATERS OVERNIGHT SUN INTO EARLY MON MORNING. OVERALL SEAS WILL INCREASE UP TO 6 TO 10 FT SUN NIGHT SUBSIDING THROUGH MON NIGHT AS WINDS BEGIN TO DIMINISH DOWN TO 10 TO 20 KTS. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY...HIGH PRESSURE WILL BUILD DOWN FROM THE NORTHWEST THROUGH MID WEEK. THE WINDS WILL DIMINISH THROUGH TUES INTO WED BUT DECENT COLD SURGE COULD KICK WINDS BACK UP TUES NIGHT TO 15 TO 20 KTS AND OUTER SEAS NEAR 6 FT. OTHERWISE EXPECT WINDS TO DROP DOWN TO 10 TO 15 KTS THROUGH THE PERIOD WITH SEAS CLOSER TO SCA TUES BUT DROPPING DOWN THROUGH WED TO 2 TO 5 FT. && .TIDES/COASTAL FLOODING... AS OF 700 PM WEDNESDAY...THE FULL MOON IS TODAY. WE EXPECT ELEVATED WATER LEVELS DURING THE TIME OF HIGH TIDE THROUGH THE WEEKEND. THE MORNING HIGH TIDE WILL BE HIGHEST AND THIS IS WHEN WE EXPECT THE TIDE TO COME UP WELL ONTO THE BEACH. STRONG NNE WINDS SUNDAY AND SUNDAY NIGHT WILL HELP TO ENHANCE THE ASTRONOMICAL EFFECTS. THE LOWER CAPE FEAR RIVER WILL ALSO EXPERIENCE HIGHER THAN PREDICTED WATER LEVELS AND MAY REACH COASTAL FLOOD ADVISORY CRITERIA DURING THE MORNING HIGH TIDE THROUGH THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EST MONDAY FOR AMZ254-256. GALE WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR AMZ250-252. && $$ NEAR TERM...MJC SHORT TERM...RGZ LONG TERM...RGZ AVIATION...MJC/DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
344 AM EST SAT DEC 6 2014 .SYNOPSIS...A SHORTWAVE TROUGH INITIALLY OVER THE MID MS AND TN VALLEYS WILL AMPLIFY ACROSS THE SOUTHERN APPALACHIANS AND CAROLINAS THROUGH TONIGHT. AN ACCOMPANYING SURFACE LOW OVER THE LOWER OH AND TN VALLEY WILL RE-DEVELOP OVER VA/NC TODAY...THEN BEGIN TO INTENSIFY AS IT APPROACHES A COASTAL FRONT ALONG THE NC COAST THIS EVENING- TONIGHT. MEANWHILE...ARCTIC HIGH PRESSURE WILL STRENGTHEN AS IT MIGRATES FROM THE NORTHERN PLAINS TO NEW ENGLAND...THE SOUTHERN PERIPHERY OF WHICH WILL RIDGE SOUTH INTO NC LATE TONIGHT THROUGH SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM SATURDAY... A COASTAL FRONT ALONG THE SOUTHEAST AND MIDDLE ATLANTIC COASTS HAS CAUSED A PIECE OF THE 1040 MB MODIFIED ARCTIC CENTERED NEAR NEWFOUNDLAND TO BREAK OFF OVER THE CAROLINAS THIS MORNING...AND THIS 1027 MB HIGH WILL LIKELY ESTABLISH A SHORT-LIVED IN-SITU CAD EVENT OVER AT LEAST THE WESTERN PIEDMONT TODAY. WHETHER OR NOT THE WEDGE IS ESTABLISHED EAST ACROSS THE REMAINDER OF CENTRAL NC IS MORE IN QUESTION...SINCE IT SEEMS THE UPSTREAM PRE-FRONTAL BAND OF RAIN NOW CROSSING THE SOUTHERN-CENTRAL APPALACHIANS HAS BEEN FALLING MOSTLY FROM MID LEVEL CEILINGS...AND AS SUCH...WOULD MAKE IT LESS LIKELY TO FULLY SATURATE THE LOW LEVELS AND HELP ESTABLISH A WEDGE. IN FACT...BOTH THE RAP AND HRRR SUGGEST THE INITIAL BAND OF IFR-MVFR CEILINGS CENTERED FROM NEAR CAE TO RDU TO RIC THIS MORNING WILL DRIFT EAST THROUGH MIDDAY...AND PROVIDE FOR A PERIOD OF MOSTLY MID- HIGH LEVEL CLOUDS AND MODEST INSOLATION DURING THE MIDDAY-EARLY AFTERNOON HOURS. THE MAIN SENSIBLE WEATHER IMPACT WITH THIS UNCERTAINTY REGARDS TEMPERATURES...WHICH WOULD BE HELD IN THE MID- UPPER 40S OVER THE NW PIEDMONT (SIMILAR TO FRI) TO GENERALLY MID 50S ELSEWHERE. BASED ON UPSTREAM OBSERVATIONS OF RAIN FROM MOSTLY MID CLOUDS...WILL TREND HIGH TEMPS TOWARD SOME MODEST INSOLATION...WITH HIGHS RANGING FROM THE MIDDLE 50S TO NEAR 60 DEGREES...EXCEPT AROUND 50 DEGREES OR SO IN THE WESTERN PIEDMONT WHERE THE OPPORTUNITY FOR INSOLATION WILL BE MORE LIMITED BETWEEN THE PRE-FRONTAL RAIN BAND...AND A TRAILING SEPARATE AREA OF SHALLOW CONVECTIVE PRECIPITATION FORECAST TO MOVE ACROSS THE AREA LATER THIS AFTERNOON. THAT TRAILING PRECIPITATION WILL BE FUELED BY SUBSTANTIAL COOLING ALOFT ACCOMPANYING A PARENT SHORTWAVE TROUGH ALOFT...ATOP A WARM AND MOIST...40 KT LLJ. THE ASSOCIATED STRONG DIFFERENTIAL THERMAL ADVECTION WILL CAUSE H85-5 LAPSE RATES TO STEEPEN IN EXCESS OF 6.5 C/KM OVER CENTRAL NC...COINCIDENT WITH 50-80 METER MID LEVEL HEIGHT FALLS ACCOMPANYING THE PARENT SHORTWAVE TROUGH ALOFT. FORECAST GUIDANCE CONTINUES TO SUGGEST THAT A POCKET OF UP TO A FEW HUNDRED J/KG OF MUCAPE WILL CONSEQUENTLY DEVELOP OVER OUR AREA THIS AFTERNOON...WHICH WILL SUPPORT THE EASTWARD PROGRESSION AND/OR RE- DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON. THOUGH SHOWERS AND ISOLATED STORMS WILL MOVE EAST WITH THE PASSAGE OF A THE OCCLUDED/COLD FRONT THIS EVENING...THE DEEPENING OF A SURFACE LOW AS IT ENCOUNTERS THE COASTAL FRONT WILL MAINTAIN A MOIST NNE FLOW THAT WILL LIKELY RESULT IN CONSIDERABLE LOW OVERCAST AND AREAS OF LIGHT RAIN OR DRIZZLE...WHICH WILL ONLY SLOWLY EDGE EASTWARD THROUGH SUN MORNING...PARTICULARLY OVER THE EASTERN TWO THIRDS OF THE CWFA. LOWS MOSTLY IN THE LOWER TO MIDDLE 40S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 340 AM SATURDAY... SUNDAY AND SUNDAY NIGHT: BRIEF SHORTWAVE RIDGING WILL BUILD EAST ACROSS OUR REGION AND CAUSE STRONG ARCTIC HIGH PRESSURE CENTERED OVER NEW ENGLAND TO RIDGE DOWN THE EAST COAST THIS PERIOD...IN ADVANCE OF A PAIR OF PHASED (OR NEARLY SO) SHORTWAVE TROUGHS FORECAST TO AMPLIFY FROM THE PLAINS TO THE MS VALLEY THROUGH SUN NIGHT. DESPITE MAINLY CLEAR SKIES...EXCEPT SOME LINGERING LOW CLOUDS OVER EASTERN NC...A BRISK AND GUSTY NE WIND WILL RESULT IN RATHER CHILLY CONDITIONS...WITH HIGHS MOSTLY IN THE MID-UPPER 40S (TO NEAR 50 SOUTH). THE AMPLIFICATION OF THE AFOREMENTIONED TROUGHS ALOFT WILL CAUSE THE LOW LEVEL FLOW (925 MB) TO ASSUME AN INCREASINGLY EASTERLY COMPONENT (TOWARD THE PRESSURE FALLS ACCOMPANYING HE APPROACHING TROUGH)..SUCH THAT THE LOW CLOUDS OVER THE EASTERN PART OF THE STATE WILL DEVELOP/ADVECT WSW ACROSS CENTRAL NC THROUGH MON MORNING. LOWS CENTERED IN THE MIDDLE 30S. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 335 AM SATURDAY... CONFIDENCE IS LOWER THAN DESIRED FOR A DAY 3 (MONDAY) FORECAST DUE TO MODEL DIFFERENCES REGARDING THE INTERACTION OF NORTHERN AND SOUTHERN STREAM SHORTWAVES AS THEY CROSS THE CENTRAL AND EASTERN US. MODELS HAVE BEEN COMING INTO A LITTLE BETTER AGREEMENT...SHOWING THE LEAD SOUTHERN STREAM SHORTWAVE MOVING FROM THE DEEP SOUTH ACROSS THE CAROLINAS ON MONDAY...WITH A NORTHERN STREAM WAVE TO DIVE SOUTH ACROSS THE REGION ON TUESDAY. IN RESPONSE TO THE LEAD WAVE...A SURFACE LOW OFF THE SOUTHEAST COAST WILL RE-INTENSIFY AND LIFT NORTH ALONG THE EAST COAST. THE NAM AND CANADIAN ARE STRONG OUTLIERS REGARDING THE STRENGTH OF THE LOW AND ASSOCIATED PRECEDING EASTERLY FLOW...PRODUCING HEAVIER PRECIP EARLIER ON MONDAY. THE ECMWF IS A LITTLE MORE AMPLIFIED WITH THE LEAD WAVE...RESULTING MORE PRECIP THAN THE GFS...BUT STILL RELATIVELY LIGHT AND NOT UNTIL MONDAY AFTERNOON. THIS HAS SOME SIGNIFICANCE...AS A STRONG 1040+ MB SURFACE HIGH EXTENDING INTO THE NC FROM NEW ENGLAND WILL BE RETREATING DURING THE DAY BUT WOULD OFFER SOME PTYPE CONCERNS IN THE NORTHWEST PIEDMONT WITH PRECIP EARLY MONDAY MORNING...AS THE NAM DEPICTS. HOWEVER THIS IS DISCOUNTED AT THIS TIME. WILL SHOW POPS INCREASING BY MIDDAY...SLIGHT CHANCE WEST TO CHANCE IN THE EAST...ENDING FROM SOUTHWEST TO NORTHEAST MONDAY NIGHT AS THE SURFACE LOW MOVES OFF TO THE NORTHEAST. THE QPF FORECAST IS FOR LESS THAN A TENTH OF AN INCH...BUT WOULDNT BE SURPRISED TO SEE MODELS PRODUCE MORE PRECIP IN LATER RUNS. HAVE LOWERED HIGHS A FEW DEGREES ACROSS THE PIEDMONT BASED ON INCREASING POTENTIAL FOR PRECIP...RANGING FROM LOWER 40S NORTHWEST TO NEAR 50 SOUTHEAST. LOWS MONDAY NIGHT IN THE LOWER 30S NORTHEAST TO UPPER 30S SOUTHEAST. A STRONG NORTHERN STREAM SHORTWAVE WILL DIVE ACROSS NC ON TUESDAY....FOLLOWED BY A REINFORCING SHOT OF COLD ADVECTION TUESDAY NIGHT. THE ECMWF SPITS OUT SOME VERY LIGHT QPF ACROSS THE NORTH TUESDAY AFTERNOON...BUT WILL HOLD OFF ON INTRODUCING POPS AS MOISTURE WILL BE LIMITED. HIGH PRESSURE IS THEN FORECAST TO BUILD ACROSS THEN BUILD SLOWLY ACROSS THE SOUTHEAST BETWEEN AN UPPER LOW THAT CLOSES OFF OVER NEW ENGLAND AND RIDGING OVER THE CENTRAL US. TEMPS MAY SLOWLY MODERATE BUT WILL REMAIN AT OR JUST BELOW NORMAL. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 145 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS HAS DEVELOPED AND SPREAD DIRECTLY ACROSS THE CENTRAL CAROLINAS THIS MORNING...CENTERED FROM NEAR CAE TO RDU TO TDF...OR JUST EAST OF THE TRIAD TERMINALS AND JUST WEST OF FAY. THIS CLOUD BAND IS FORECAST TO HOLD RELATIVELY STATIONARY THROUGH 12Z...BEFORE SHIFTING EAST TOWARD RWI THROUGH 18Z. MEANWHILE...A PRE- FRONTAL BAND OF RAIN AND OCCASIONAL IFR-MVFR CONDITIONS...AMIDST OTHERWISE LOW VFR CEILINGS...WILL ARRIVE FROM THE WEST BETWEEN 10- 12Z AT WESTERN TERMINALS TO 14-17Z AT EASTERN ONES...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-22Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING WNW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB-VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...BLS AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
335 AM EST SAT DEC 6 2014 .SYNOPSIS...A SHORTWAVE TROUGH INITIALLY OVER THE MID MS AND TN VALLEYS WILL AMPLIFY ACROSS THE SOUTHERN APPALACHIANS AND CAROLINAS THROUGH TONIGHT. AN ACCOMPANYING SURFACE LOW OVER THE LOWER OH AND TN VALLEY WILL RE-DEVELOP OVER VA/NC TODAY...THEN BEGIN TO INTENSIFY AS IT APPROACHES A COASTAL FRONT ALONG THE NC COAST THIS EVENING- TONIGHT. MEANWHILE...ARCTIC HIGH PRESSURE WILL STRENGTHEN AS IT MIGRATES FROM THE NORTHERN PLAINS TO NEW ENGLAND...THE SOUTHERN PERIPHERY OF WHICH WILL RIDGE SOUTH INTO NC LATE TONIGHT THROUGH SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM SATURDAY... A COASTAL FRONT ALONG THE SOUTHEAST AND MIDDLE ATLANTIC COASTS HAS CAUSED A PIECE OF THE 1040 MB MODIFIED ARCTIC CENTERED NEAR NEWFOUNDLAND TO BREAK OFF OVER THE CAROLINAS THIS MORNING...AND THIS 1027 MB HIGH WILL LIKELY ESTABLISH A SHORT-LIVED IN-SITU CAD EVENT OVER AT LEAST THE WESTERN PIEDMONT TODAY. WHETHER OR NOT THE WEDGE IS ESTABLISHED EAST ACROSS THE REMAINDER OF CENTRAL NC IS MORE IN QUESTION...SINCE IT SEEMS THE UPSTREAM PRE-FRONTAL BAND OF RAIN NOW CROSSING THE SOUTHERN-CENTRAL APPALACHIANS HAS BEEN FALLING MOSTLY FROM MID LEVEL CEILINGS...AND AS SUCH...WOULD MAKE IT LESS LIKELY TO FULLY SATURATE THE LOW LEVELS AND HELP ESTABLISH A WEDGE. IN FACT...BOTH THE RAP AND HRRR SUGGEST THE INITIAL BAND OF IFR-MVFR CEILINGS CENTERED FROM NEAR CAE TO RDU TO RIC THIS MORNING WILL DRIFT EAST THROUGH MIDDAY...AND PROVIDE FOR A PERIOD OF MOSTLY MID- HIGH LEVEL CLOUDS AND MODEST INSOLATION DURING THE MIDDAY-EARLY AFTERNOON HOURS. THE MAIN SENSIBLE WEATHER IMPACT WITH THIS UNCERTAINTY REGARDS TEMPERATURES...WHICH WOULD BE HELD IN THE MID- UPPER 40S OVER THE NW PIEDMONT (SIMILAR TO FRI) TO GENERALLY MID 50S ELSEWHERE. BASED ON UPSTREAM OBSERVATIONS OF RAIN FROM MOSTLY MID CLOUDS...WILL TREND HIGH TEMPS TOWARD SOME MODEST INSOLATION...WITH HIGHS RANGING FROM THE MIDDLE 50S TO NEAR 60 DEGREES...EXCEPT AROUND 50 DEGREES OR SO IN THE WESTERN PIEDMONT WHERE THE OPPORTUNITY FOR INSOLATION WILL BE MORE LIMITED BETWEEN THE PRE-FRONTAL RAIN BAND...AND A TRAILING SEPARATE AREA OF SHALLOW CONVECTIVE PRECIPITATION FORECAST TO MOVE ACROSS THE AREA LATER THIS AFTERNOON. THAT TRAILING PRECIPITATION...WILL BE FUELED BY SUBSTANTIAL COOLING ALOFT ACCOMPANYING A PARENT SHORTWAVE TROUGH ALOFT...ATOP A WARM AND MOIST...40 KT LLJ. THE ASSOCIATED STRONG DIFFERENTIAL THERMAL ADVECTION WILL CAUSE H85-5 LAPSE RATES TO STEEPEN IN EXCESS OF 6.5 C/KM OVER CENTRAL NC...COINCIDENT WITH 50-80 METER MID LEVEL HEIGHT FALLS ACCOMPANYING THE PARENT SHORTWAVE TROUGH ALOFT. FORECAST GUIDANCE CONTINUES TO SUGGEST THAT A POCKET OF UP TO A FEW HUNDRED J/KG OF MUCAPE WILL CONSEQUENTLY DEVELOP OVER OUR AREA THIS AFTERNOON...WHICH WILL SUPPORT THE EASTWARD PROGRESSION AND/OR RE- DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON. THOUGH SHOWERS AND ISOLATED STORMS WILL MOVE EAST WITH THE PASSAGE OF A THE OCCLUDED/COLD FRONT THIS EVENING...THE DEEPENING OF A SURFACE LOW AS IT ENCOUNTERS THE COASTAL FRONT WILL MAINTAIN A MOIST NNE FLOW THAT WILL LIKELY RESULT IN CONSIDERABLE LOW OVERCAST AND AREAS OF LIGHT RAIN OR DRIZZLE...WHICH WILL ONLY SLOWLY EDGE EASTWARD THROUGH SUN MORNING...PARTICULARLY OVER THE EASTERN TWO THIRDS OF THE CWFA. LOWS MOSTLY IN THE LOWER TO MIDDLE 40S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 220 PM FRIDAY... SUNDAY AND SUNDAY NIGHT: THE LATEST RUN OF THE ECMWF AGREES WELL WITH THE GFS IN REGARD TO THE LOW AND ITS ASSOCIATED COLD FRONT MOVING OFF THE CAROLINA COAST PRIOR TO 12Z SUNDAY. AS SUCH...HAVE A DRY FORECAST FOR SUNDAY AND SUNDAY NIGHT. THE BIG QUESTION WILL BE HOW QUICKLY THE SKIES CLEAR AND HOW THAT WILL AFFECT TEMPERATURES. FOR NOW...EXPECT HIGHS IN THE UPPER 40S NW TO 723MID 50S SOUTH AND EAST...ALTHOUGH IF SKIES CLEAR QUICKER/SLOWER THAT COULD CHANGE BY A COUPLE/FEW DEGREES. LOWS GENERALLY IN LOW 30S NW TO UPPER 30S SE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 335 AM SATURDAY... CONFIDENCE IS LOWER THAN DESIRED FOR A DAY 3 (MONDAY) FORECAST DUE TO MODEL DIFFERENCES REGARDING THE INTERACTION OF NORTHERN AND SOUTHERN STREAM SHORTWAVES AS THEY CROSS THE CENTRAL AND EASTERN US. MODELS HAVE BEEN COMING INTO A LITTLE BETTER AGREEMENT...SHOWING THE LEAD SOUTHERN STREAM SHORTWAVE MOVING FROM THE DEEP SOUTH ACROSS THE CAROLINAS ON MONDAY...WITH A NORTHERN STREAM WAVE TO DIVE SOUTH ACROSS THE REGION ON TUESDAY. IN RESPONSE TO THE LEAD WAVE...A SURFACE LOW OFF THE SOUTHEAST COAST WILL RE-INTENSIFY AND LIFT NORTH ALONG THE EAST COAST. THE NAM AND CANADIAN ARE STRONG OUTLIERS REGARDING THE STRENGTH OF THE LOW AND ASSOCIATED PRECEDING EASTERLY FLOW...PRODUCING HEAVIER PRECIP EARLIER ON MONDAY. THE ECMWF IS A LITTLE MORE AMPLIFIED WITH THE LEAD WAVE...RESULTING MORE PRECIP THAN THE GFS...BUT STILL RELATIVELY LIGHT AND NOT UNTIL MONDAY AFTERNOON. THIS HAS SOME SIGNIFICANCE...AS A STRONG 1040+ MB SURFACE HIGH EXTENDING INTO THE NC FROM NEW ENGLAND WILL BE RETREATING DURING THE DAY BUT WOULD OFFER SOME PTYPE CONCERNS IN THE NORTHWEST PIEDMONT WITH PRECIP EARLY MONDAY MORNING...AS THE NAM DEPICTS. HOWEVER THIS IS DISCOUNTED AT THIS TIME. WILL SHOW POPS INCREASING BY MIDDAY...SLIGHT CHANCE WEST TO CHANCE IN THE EAST...ENDING FROM SOUTHWEST TO NORTHEAST MONDAY NIGHT AS THE SURFACE LOW MOVES OFF TO THE NORTHEAST. THE QPF FORECAST IS FOR LESS THAN A TENTH OF AN INCH...BUT WOULDNT BE SURPRISED TO SEE MODELS PRODUCE MORE PRECIP IN LATER RUNS. HAVE LOWERED HIGHS A FEW DEGREES ACROSS THE PIEDMONT BASED ON INCREASING POTENTIAL FOR PRECIP...RANGING FROM LOWER 40S NORTHWEST TO NEAR 50 SOUTHEAST. LOWS MONDAY NIGHT IN THE LOWER 30S NORTHEAST TO UPPER 30S SOUTHEAST. A STRONG NORTHERN STREAM SHORTWAVE WILL DIVE ACROSS NC ON TUESDAY....FOLLOWED BY A REINFORCING SHOT OF COLD ADVECTION TUESDAY NIGHT. THE ECMWF SPITS OUT SOME VERY LIGHT QPF ACROSS THE NORTH TUESDAY AFTERNOON...BUT WILL HOLD OFF ON INTRODUCING POPS AS MOISTURE WILL BE LIMITED. HIGH PRESSURE IS THEN FORECAST TO BUILD ACROSS THEN BUILD SLOWLY ACROSS THE SOUTHEAST BETWEEN AN UPPER LOW THAT CLOSES OFF OVER NEW ENGLAND AND RIDGING OVER THE CENTRAL US. TEMPS MAY SLOWLY MODERATE BUT WILL REMAIN AT OR JUST BELOW NORMAL. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 145 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS HAS DEVELOPED AND SPREAD DIRECTLY ACROSS THE CENTRAL CAROLINAS THIS MORNING...CENTERED FROM NEAR CAE TO RDU TO TDF...OR JUST EAST OF THE TRIAD TERMINALS AND JUST WEST OF FAY. THIS CLOUD BAND IS FORECAST TO HOLD RELATIVELY STATIONARY THROUGH 12Z...BEFORE SHIFTING EAST TOWARD RWI THROUGH 18Z. MEANWHILE...A PRE- FRONTAL BAND OF RAIN AND OCCASIONAL IFR-MVFR CONDITIONS...AMIDST OTHERWISE LOW VFR CEILINGS...WILL ARRIVE FROM THE WEST BETWEEN 10- 12Z AT WESTERN TERMINALS TO 14-17Z AT EASTERN ONES...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-22Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING WNW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB-VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...WSS LONG TERM...BLS AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EST SAT DEC 6 2014 .SYNOPSIS...A SHORTWAVE TROUGH INITIALLY OVER THE MID MS AND TN VALLEYS WILL AMPLIFY ACROSS THE SOUTHERN APPALACHIANS AND CAROLINAS THROUGH TONIGHT. AN ACCOMPANYING SURFACE LOW OVER THE LOWER OH AND TN VALLEY WILL RE-DEVELOP OVER VA/NC TODAY...THEN BEGIN TO INTENSIFY AS IT APPROACHES A COASTAL FRONT ALONG THE NC COAST THIS EVENING- TONIGHT. MEANWHILE...ARCTIC HIGH PRESSURE WILL STRENGTHEN AS IT MIGRATES FROM THE NORTHERN PLAINS TO NEW ENGLAND...THE SOUTHERN PERIPHERY OF WHICH WILL RIDGE SOUTH INTO NC LATE TONIGHT THROUGH SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM SATURDAY... A COASTAL FRONT ALONG THE SOUTHEAST AND MIDDLE ATLANTIC COASTS HAS CAUSED A PIECE OF THE 1040 MB MODIFIED ARCTIC CENTERED NEAR NEWFOUNDLAND TO BREAK OFF OVER THE CAROLINAS THIS MORNING...AND THIS 1027 MB HIGH WILL LIKELY ESTABLISH A SHORT-LIVED IN-SITU CAD EVENT OVER AT LEAST THE WESTERN PIEDMONT TODAY. WHETHER OR NOT THE WEDGE IS ESTABLISHED EAST ACROSS THE REMAINDER OF CENTRAL NC IS MORE IN QUESTION...SINCE IT SEEMS THE UPSTREAM PRE-FRONTAL BAND OF RAIN NOW CROSSING THE SOUTHERN-CENTRAL APPALACHIANS HAS BEEN FALLING MOSTLY FROM MID LEVEL CEILINGS...AND AS SUCH...WOULD MAKE IT LESS LIKELY TO FULLY SATURATE THE LOW LEVELS AND HELP ESTABLISH A WEDGE. IN FACT...BOTH THE RAP AND HRRR SUGGEST THE INITIAL BAND OF IFR-MVFR CEILINGS CENTERED FROM NEAR CAE TO RDU TO RIC THIS MORNING WILL DRIFT EAST THROUGH MIDDAY...AND PROVIDE FOR A PERIOD OF MOSTLY MID- HIGH LEVEL CLOUDS AND MODEST INSOLATION DURING THE MIDDAY-EARLY AFTERNOON HOURS. THE MAIN SENSIBLE WEATHER IMPACT WITH THIS UNCERTAINTY REGARDS TEMPERATURES...WHICH WOULD BE HELD IN THE MID- UPPER 40S OVER THE NW PIEDMONT (SIMILAR TO FRI) TO GENERALLY MID 50S ELSEWHERE. BASED ON UPSTREAM OBSERVATIONS OF RAIN FROM MOSTLY MID CLOUDS...WILL TREND HIGH TEMPS TOWARD SOME MODEST INSOLATION...WITH HIGHS RANGING FROM THE MIDDLE 50S TO NEAR 60 DEGREES...EXCEPT AROUND 50 DEGREES OR SO IN THE WESTERN PIEDMONT WHERE THE OPPORTUNITY FOR INSOLATION WILL BE MORE LIMITED BETWEEN THE PRE-FRONTAL RAIN BAND...AND A TRAILING SEPARATE AREA OF SHALLOW CONVECTIVE PRECIPITATION FORECAST TO MOVE ACROSS THE AREA LATER THIS AFTERNOON. THAT TRAILING PRECIPITATION...WILL BE FUELED BY SUBSTANTIAL COOLING ALOFT ACCOMPANYING A PARENT SHORTWAVE TROUGH ALOFT...ATOP A WARM AND MOIST...40 KT LLJ. THE ASSOCIATED STRONG DIFFERENTIAL THERMAL ADVECTION WILL CAUSE H85-5 LAPSE RATES TO STEEPEN IN EXCESS OF 6.5 C/KM OVER CENTRAL NC...COINCIDENT WITH 50-80 METER MID LEVEL HEIGHT FALLS ACCOMPANYING THE PARENT SHORTWAVE TROUGH ALOFT. FORECAST GUIDANCE CONTINUES TO SUGGEST THAT A POCKET OF UP TO A FEW HUNDRED J/KG OF MUCAPE WILL CONSEQUENTLY DEVELOP OVER OUR AREA THIS AFTERNOON...WHICH WILL SUPPORT THE EASTWARD PROGRESSION AND/OR RE- DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON. THOUGH SHOWERS AND ISOLATED STORMS WILL MOVE EAST WITH THE PASSAGE OF A THE OCCLUDED/COLD FRONT THIS EVENING...THE DEEPENING OF A SURFACE LOW AS IT ENCOUNTERS THE COASTAL FRONT WILL MAINTAIN A MOIST NNE FLOW THAT WILL LIKELY RESULT IN CONSIDERABLE LOW OVERCAST AND AREAS OF LIGHT RAIN OR DRIZZLE...WHICH WILL ONLY SLOWLY EDGE EASTWARD THROUGH SUN MORNING...PARTICULARLY OVER THE EASTERN TWO THIRDS OF THE CWFA. LOWS MOSTLY IN THE LOWER TO MIDDLE 40S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 220 PM FRIDAY... SUNDAY AND SUNDAY NIGHT: THE LATEST RUN OF THE ECMWF AGREES WELL WITH THE GFS IN REGARD TO THE LOW AND ITS ASSOCIATED COLD FRONT MOVING OFF THE CAROLINA COAST PRIOR TO 12Z SUNDAY. AS SUCH...HAVE A DRY FORECAST FOR SUNDAY AND SUNDAY NIGHT. THE BIG QUESTION WILL BE HOW QUICKLY THE SKIES CLEAR AND HOW THAT WILL AFFECT TEMPERATURES. FOR NOW...EXPECT HIGHS IN THE UPPER 40S NW TO 723MID 50S SOUTH AND EAST...ALTHOUGH IF SKIES CLEAR QUICKER/SLOWER THAT COULD CHANGE BY A COUPLE/FEW DEGREES. LOWS GENERALLY IN LOW 30S NW TO UPPER 30S SE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 220 PM FRIDAY... MONDAY THROUGH FRIDAY: CONFIDENCE IS STILL NOT TERRIBLY HIGH FOR NEXT WEEK...HOWEVER IT HAS INCREASED SOME OVERALL AS THE MODELS APPEAR TO BE SLOWLY COMING INTO BETTER AGREEMENT. THE ECMWF SEEMS TO BE TRENDING MORE TOWARD THE GFS WITH THE UPPER LEVEL LOW THAT MOVES THROUGH THE GREAT LAKES AND NORTHEAST U.S. TOWARD THE END OF NEXT WEEK. ALTHOUGH IT CONTINUES TO BE DEEPER WITH THE UPPER LEVEL TROUGH AND STILL TRIES TO GENERATE A BIT OF PRECIPITATION OVER PORTIONS OF THE CAROLINAS EARLY IN THE WEEK. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO THAT LOW...AND GIVEN THE MODEL TREND...EXPECT IT TO STAY MAINLY WELL NORTH OF THE REGION AND BE OF LITTLE CONSEQUENCE IN THE PRECIPITATION DEPARTMENT FOR CENTRAL NC AT THIS TIME. WITH THAT HYPOTHESIS IN MIND...EXPECT NEXT WEEK TO BE GENERALLY DRY...WITH HIGH PRESSURE DOMINATING AT THE SURFACE. THE FIRST HIGH WILL RIDGE IN FROM THE NORTHEAST AND RESULT IN A WEDGE OF A COLD AIR OVER THE AREA. A REINFORCING SHOT OF COLD AIR WILL PUSH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH ANOTHER AREA OF HIGH PRESSURE SUBSEQUENTLY BUILDING IN THROUGH THE END OF THE WEEK. HIGHS ON MONDAY WILL BE THE COOLEST OF THE PERIOD...MID 40S NW TO LOW 50S SE. HIGHS WILL CONTINUE TO BE A LITTLE BIT OF A RO723LLER COASTER THROUGH THE REST OF THE WEEK...WITH LOW TO MID 50S EXPECTED ON TUESDAY AND FRIDAY...BUT UPPER 40S TO LOW 50S WEDNESDAY AND THURSDAY. LOWS WILL GENERALLY DECREASE FROM THE LOW 30S NW TO UPPER 30S SE MONDAY NIGHT TO UPPER 20S ACROSS THE AREA BY WED AND THU NIGHTS...MODERATING AGAIN INTO THE LOW 30S FRI NIGHT. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 145 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS HAS DEVELOPED AND SPREAD DIRECTLY ACROSS THE CENTRAL CAROLINAS THIS MORNING...CENTERED FROM NEAR CAE TO RDU TO TDF...OR JUST EAST OF THE TRIAD TERMINALS AND JUST WEST OF FAY. THIS CLOUD BAND IS FORECAST TO HOLD RELATIVELY STATIONARY THROUGH 12Z...BEFORE SHIFTING EAST TOWARD RWI THROUGH 18Z. MEANWHILE...A PRE- FRONTAL BAND OF RAIN AND OCCASIONAL IFR-MVFR CONDITIONS...AMIDST OTHERWISE LOW VFR CEILINGS...WILL ARRIVE FROM THE WEST BETWEEN 10- 12Z AT WESTERN TERMINALS TO 14-17Z AT EASTERN ONES...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-22Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING WNW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB-VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...WSS LONG TERM...KC AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 AM EST SAT DEC 6 2014 .SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE WEST TODAY...THEN CROSS OUR REGION THIS EVENING. HIGH PRESSURE WILL FOLLOW FOR SUNDAY. && .NEAR TERM /TONIGHT/... AS OF 1010 PM FRIDAY... TWO MAIN FORECAST PROBLEMS FOR THIS EVENING...THE FIRST...WILL THERE BE FOG ACROSS THE SOUTHERN COUNTIES...AND SECOND...THE ARRIVAL TIME OF THE PRECIPITATION ON SATURDAY. ADDRESSING THE FOG...MUCH OF CENTRAL NC REMAINS ENSHROUDED IN CLOUD COVER WITH SOME CLEARING ACROSS THE SOUTHWEST. VISIBILITIES FOR THE MOST PART HAVE REMAINED ABOVE TEN MILES AS DEWPOINT DEPRESSIONS HAVE ALSO REMAINED PLUS OR MINUS FIVE DEGREES. AS THE AREA OF CLEARING OVER THE SOUTHWEST MOVES EASTWARD...THERE COULD BE A FEW HOURS BEFORE SUNRISE WHEN THE TEMPERATURE DROPS TO THE DEWPOINT AND SOME PATCHY DENSE FOG WILL BE POSSIBLE. FOR THE MOST PART HOWEVER...LOW STRATUS WILL BE THE MORE LIKELY SCENARIO WITH SEVERAL SITES IN THE SANDHILLS ALREADY SHOWING MVFR CEILINGS. THE MAIN SYSTEM THAT IS EXPECTED TO GENERATE PRECIPITATION OVER THE AREA ON SATURDAY REMAINS OVER THE TENNESSEE VALLEY AND SHORT TERM MODELS ARE PROGGING THE ARRIVAL OF THE PRECIP TO BE A LITTLE BIT LATER THAN PREVIOUSLY ANTICIPATED. HAVE CUT BACK ON POPS SATURDAY MORNING AND BLEND INTO HIGHER POPS STILL EXPECTED FOR SATURDAY AFTERNOON/EVENING. THE LATEST RAP MODEL ACTUALLY SHOWS PRECIP IN OUR CWA BEGINNING FIRST IN THE EAST IN ASSOCIATION WITH A SMALLER WAVE MOVING IN OFF OF THE SW ATLANTIC AFTER 9Z AND THEN PRECIPITATION ASSOCIATED WITH THE WESTERN SYSTEM APPROACHING THE NW PIEDMONT AFTER 12Z SATURDAY. LOWS TONIGHT WILL RANGE FROM THE LOW TO MIDDLE 40S. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 310 PM FRIDAY... SATURDAY... S/W AND ASSOCIATED SURFACE FRONT WILL BE TO OUR WEST AT 18Z...CROSSING OUR REGION SATURDAY EVENING. LOW-MID LEVEL SOUTH- SOUTHWEST FLOW WILL ADVECT ABUNDANT MOISTURE INTO OUR REGION. MEANWHILE SUFFICIENT LIFT WILL BE PROVIDED BY: A.) DIVERGENCE ALOFT DUE TO THE CAROLINAS BEING IN THE FAVORABLE POSITION OF TWO JETS (ONE EXITING NEW ENGLAND WHILE THE OTHER DIVING SEWD ACROSS THE TN VALLEY); B.) 40-60M/12 HOUR MID LEVEL HEIGHT FALLS; C.) AND LATER IN THE DAY, CONVERGENCE ALONG THE SFC-850MB COLD FRONT. THIS FAVORABLE ATMOSPHERE SHOULD CAUSE NUMEROUS SHOWERS TO OVERSPREAD THE PIEDMONT AND THE NORTHERN COASTAL PLAIN DURING THE MORNING HOURS...AND INTO THE SANDHILLS AND THE REMAINDER OF THE COASTAL PLAIN IN THE AFTERNOON. POTENTIAL EXISTS FOR A FEW THUNDERSTORMS TO OCCUR SATURDAY AFTERNOON- EARLY EVENING AS MID LEVEL LAPSE RATES REACH AS HIGH AS 6.5-7 DEG C/KM AND BULK SHEAR ACHIEVES FAVORABLE VALUES 30-35KTS. LOW LEVEL INSTABILITY LACKING AS SBCAPE IS AOB 200 J/KG WHILE MUCAPE NO HIGHER THAN 200-250 J/KG LATE SATURDAY-SATURDAY EVENING. THUS...EXPECT CONVECTION TO BE ELEVATED WITH LITTLE IF ANY CHANCE OF STORMS BECOMING STRONG/SEVERE. HIGH TEMPS SATURDAY STILL A CHALLENGE...DEPENDENT UPON EXTENT OF RAIN SHOWERS. STILL FAVOR MAX TEMPS SLIGHTLY COOLER THAN GUIDANCE ACROSS THE PIEDMONT AS A SHORT-LIVED IN-SITU OR HYBRID CAD MAY SET UP EARLY SATURDAY. CONVERSELY...IF SHOWERS HOLD OFF LONG ENOUGH...TEMPS IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN MAY WARM INTO THE MID-UPPER 60S. SATURDAY NIGHT... SURFACE COLD FRONT PROGRESSES EAST ACROSS CENTRAL NC IN THE EVENING...EXITING OUR COASTAL PLAIN COUNTIES AROUND OR SHORTLY AFTER MIDNIGHT. THE 850-700MB TROUGHS FOLLOW SHORTLY AFTERWARDS. LOW-MID LEVEL N-NW FLOW IN THE WAKE OF THE TROUGH PASSAGE WILL AID TO DIMINISH SHOWER COVERAGE IN THE WEST SATURDAY EVENING...AND OVERNIGHT IN THE EAST. PARTIAL CLEARING SHOULD INITIATE IN THE NORTH-NW AFTER MIDNIGHT. SURFACE FRONTAL PASSAGE WILL BE NOTED BY WINDS VEERING TO THE N-NW AND INITIALLY GUSTING AROUND 20KTS. MIN TEMPS LOW-MID 40S NORTH TO UPPER 40S SE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 220 PM FRIDAY... SUNDAY AND SUNDAY NIGHT: THE LATEST RUN OF THE ECMWF AGREES WELL WITH THE GFS IN REGARD TO THE LOW AND ITS ASSOCIATED COLD FRONT MOVING OFF THE CAROLINA COAST PRIOR TO 12Z SUNDAY. AS SUCH...HAVE A DRY FORECAST FOR SUNDAY AND SUNDAY NIGHT. THE BIG QUESTION WILL BE HOW QUICKLY THE SKIES CLEAR AND HOW THAT WILL AFFECT TEMPERATURES. FOR NOW...EXPECT HIGHS IN THE UPPER 40S NW TO 723MID 50S SOUTH AND EAST...ALTHOUGH IF SKIES CLEAR QUICKER/SLOWER THAT COULD CHANGE BY A COUPLE/FEW DEGREES. LOWS GENERALLY IN LOW 30S NW TO UPPER 30S SE. MONDAY THROUGH FRIDAY: CONFIDENCE IS STILL NOT TERRIBLY HIGH FOR NEXT WEEK...HOWEVER IT HAS INCREASED SOME OVERALL AS THE MODELS APPEAR TO BE SLOWLY COMING INTO BETTER AGREEMENT. THE ECMWF SEEMS TO BE TRENDING MORE TOWARD THE GFS WITH THE UPPER LEVEL LOW THAT MOVES THROUGH THE GREAT LAKES AND NORTHEAST U.S. TOWARD THE END OF NEXT WEEK. ALTHOUGH IT CONTINUES TO BE DEEPER WITH THE UPPER LEVEL TROUGH AND STILL TRIES TO GENERATE A BIT OF PRECIPITATION OVER PORTIONS OF THE CAROLINAS EARLY IN THE WEEK. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO THAT LOW...AND GIVEN THE MODEL TREND...EXPECT IT TO STAY MAINLY WELL NORTH OF THE REGION AND BE OF LITTLE CONSEQUENCE IN THE PRECIPITATION DEPARTMENT FOR CENTRAL NC AT THIS TIME. WITH THAT HYPOTHESIS IN MIND...EXPECT NEXT WEEK TO BE GENERALLY DRY...WITH HIGH PRESSURE DOMINATING AT THE SURFACE. THE FIRST HIGH WILL RIDGE IN FROM THE NORTHEAST AND RESULT IN A WEDGE OF A COLD AIR OVER THE AREA. A REINFORCING SHOT OF COLD AIR WILL PUSH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH ANOTHER AREA OF HIGH PRESSURE SUBSEQUENTLY BUILDING IN THROUGH THE END OF THE WEEK. HIGHS ON MONDAY WILL BE THE COOLEST OF THE PERIOD...MID 40S NW TO LOW 50S SE. HIGHS WILL CONTINUE TO BE A LITTLE BIT OF A RO723LLER COASTER THROUGH THE REST OF THE WEEK...WITH LOW TO MID 50S EXPECTED ON TUESDAY AND FRIDAY...BUT UPPER 40S TO LOW 50S WEDNESDAY AND THURSDAY. LOWS WILL GENERALLY DECREASE FROM THE LOW 30S NW TO UPPER 30S SE MONDAY NIGHT TO UPPER 20S ACROSS THE AREA BY WED AND THU NIGHTS...MODERATING AGAIN INTO THE LOW 30S FRI NIGHT. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 145 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS HAS DEVELOPED AND SPREAD DIRECTLY ACROSS THE CENTRAL CAROLINAS THIS MORNING...CENTERED FROM NEAR CAE TO RDU TO TDF...OR JUST EAST OF THE TRIAD TERMINALS AND JUST WEST OF FAY. THIS CLOUD BAND IS FORECAST TO HOLD RELATIVELY STATIONARY THROUGH 12Z...BEFORE SHIFTING EAST TOWARD RWI THROUGH 18Z. MEANWHILE...A PRE- FRONTAL BAND OF RAIN AND OCCASIONAL IFR-MVFR CONDITIONS...AMIDST OTHERWISE LOW VFR CEILINGS...WILL ARRIVE FROM THE WEST BETWEEN 10- 12Z AT WESTERN TERMINALS TO 14-17Z AT EASTERN ONES...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-22Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING WNW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB-VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...KC AVIATION...MWS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
124 AM EST SAT DEC 6 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A COASTAL TROUGH WILL LIFT NORTH AS A WARM FRONT ON SATURDAY...AHEAD OF A COLD FRONT WHICH WILL MOVE ACROSS THE AREA SATURDAY NIGHT. THIS COLD FRONT WILL BRING A PERIOD OF SHOWERS WITH AN ISOLATED THUNDERSTORM POSSIBLE. A STRONG WEDGE OF HIGH PRESSURE WILL BUILD SOUTH SUNDAY AND MONDAY...BRINGING GUSTY NORTH WINDS AND MUCH COOLER TEMPERATURES. CANADIAN HIGH PRESSURE NEXT WEEK WILL MAINTAIN SEASONABLY COOL TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 124 AM SATURDAY...A COASTAL TROUGH DEVELOPING ACROSS THE WATERS IS EXPECTED TO DRIFT TO THE COAST OVERNIGHT. CONVERGENT FLOW IN ASSOCIATION WITH THE TROUGH SHOULD HELP TO BRING SOME OF THE OFFSHORE SHOWERS ONTO THE COAST LATE TONIGHT. THE HIGH RESOLUTION HRRR IS MOST BULLISH WITH THIS SCENARIO...PRIMARILY FOR THE CAPE FEAR AREA LATE TONIGHT. OTHERWISE AS CHILLY HIGH PRESSURE DRIFTS OFFSHORE AND A TROUGH APPROACHES FROM THE W...A DEEP S TO SW FLOW WILL ENVELOP THE EASTERN CAROLINAS. THE COLUMN WILL CONTINUE TO SLOWLY MOISTEN...PRECIPITABLE WATER VALUES WILL REACH NEAR 1.25 INCHES BY SUNRISE. SHOWERS ASSOCIATED WITH THE AFOREMENTIONED TROUGH WILL REMAIN W OF THE FORECAST AREA INTO EARLY SAT MORNING. A WARM AIR ADVECTION PATTERN AND INCREASING MOISTURE CONTENT WILL BRING A GOOD DEAL OF CLOUDINESS THROUGH THE NIGHT. THE CLOUDS SHOULD HELP TO FLATTEN THE TEMP CURVE WITH LOWS MAINLY IN THE MID AND UPPER 40S INLAND AND LOWER 50S AT THE COAST...SO LITTLE TEMP MOVEMENT THROUGH THE NIGHT. ALTHOUGH MODELS ARE INDICATING A PRONOUNCED NEAR SURFACE INVERSION DEVELOPING...THEY ARE RELUCTANT TO SATURATE THE LEVEL CLOSEST TO THE GROUND. ALSO... USING A UPS FOG METHODOLOGY GRIDDED SMART TOOL...FOG IS EXPECTED TO DEVELOP W OF THE FORECAST AREA AND ADVECT NORTHWARD WITH TIME. THUS...STILL LOOKS AS THOUGH SIGNIFICANT FOG WILL HAVE A DIFFICULT TIME DEVELOPING AND WILL FAVOR LOW STRATUS OVER FOG AT THIS TIME...BUT CONTINUE TO MONITOR NEAR TERM TRENDS. THIS LOW STRATUS MAY PRODUCE SOME SPOTTY DRIZZLE FROM TIME TO TIME AND HAVE ADDED PATCHY DRIZZLE TO THE FORECAST TOWARD MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COASTAL TROUGH LIFTING NORTH AS A WARM FRONT SATURDAY MORNING WILL CREATE A WARM DAY...ESPECIALLY ALONG THE COAST...BUT RAIN CHANCES WILL INCREASE RAPIDLY LATE IN THE DAY. AS THE COASTAL TROUGH LIFTS NORTH EARLY...WAA WILL FOLLOW THROUGH THE AFTN...WITH 850MB TEMPS CLIMBING TO AROUND 10C BY SATURDAY AFTN. AS THIS OCCURS HOWEVER...CLOUD COVER WILL BE ON THE INCREASE THANKS TO MOIST ADVECTION AND PVA AHEAD OF A SHORTWAVE WHICH WILL MOVE JUST NORTH OF THE AREA SATURDAY NIGHT. BENEATH THIS SHORTWAVE...A SURFACE LOW WILL PUSH EAST NEAR THE NC/VA BORDER...DRAGGING A COLD FRONT ACROSS THE CWA SATURDAY NIGHT. AS PWATS RISE TO ABOUT 1.25 INCHES AND MID-LEVEL LAPSE RATES CLIMB TOWARDS 7C/KM...SCATTERED SHOWERS WITH ISOLATED TSTMS ARE EXPECTED. INSTABILITY REMAINS MINIMAL...BUT CANNOT RULE OUT A FEW LIGHTNING STRIKES...AND THIS IS ECHOED BY THE GENERAL RISK ENCOMPASSING THE ILM CWA IN THE SWODY2. TOTAL QPF WILL NOT BE VERY HIGH...BUT BRIEF PERIODS OF HEAVY RAIN IS POSSIBLE WITHIN A FEW HOURS EITHER SIDE OF SATURDAY EVENING. COOL ADVECTION BEGINS IN EARNEST BEHIND THE COLD FRONT LATE SATURDAY NIGHT...SO TEMPS WHICH WILL RISE TOWARDS 70 ALONG THE COAST SATURDAY AFTN...MID 60S WELL INLAND...WILL DROP RAPIDLY INTO THE LOW 40S WELL NW...TO AROUND 50 AT THE COAST...BY SUNDAY MORNING. A QUIETER BUT MUCH COOLER DAY ON SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE DEVELOPS BEHIND THE COLD FRONT FROM SATURDAY NIGHT. WITH LOW-LEVEL MOISTURE PROGGED TO REMAIN HIGH BENEATH THE WEDGE...PARTLY TO MOSTLY CLOUDY CONDITIONS WILL PERSIST MUCH OF SUNDAY. THIS COMBINED WITH COOL ADVECTION WILL LIMIT WARMING...AND HIGHS MAY BE REACHED VERY EARLY IN THE DAY...WITH LITTLE DIURNAL RANGE. EXPECT HIGHS ONLY IN THE LOW 50S IN THE FAR NORTH...TO MID 50S IN THE SOUTH. SOME CLEARING WILL OCCUR VERY LATE...AND CONTINUED CAA WILL HELP MINS FALL INTO THE UPPER 30S SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...THE MID LEVEL PATTERN WILL BE QUITE PROGRESSIVE THROUGH THE PERIOD WITH THE AREA REMAINING VOID OF ANY SIGNIFICANT PRECIPITATION. INITIALLY A LINGERING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST MAY PROVIDE A FEW SHOWERS...MORESO ALONG THE COAST MONDAY BEFORE A COLD FRONT...ASSOCIATED WITH FAIRLY STRONG SHORTWAVE MOVING THROUGH THE MIDWEST SWEEPS THE AREA CLEAN. BEYOND THIS A WEAKENING CYCLONIC FLOW ALOFT WILL PREVAIL ACROSS THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD DOWN FROM THE UPPER MIDWEST TO ESSENTIALLY OVER THE AREA BY FRIDAY THUS A DRY FORECAST. TEMPERATURES TRENDS LOOK A LITTLE BELOW CLIMATOLOGY WITH HIGHS MOSTLY IN THE 50S AND LOWS IN THE LOWER TO MIDDLE 30S && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RATHER LOW CONFIDENCE ON THE BACK END OF THE FORECAST PERIOD WITH RESPECT TO CEILINGS AND THE TIMING OF PRECIP. LOOKS LIKE THERE COULD BE TWO BATCHES OF RAIN/SHOWERS: THE FIRST AROUND SUNRISE WITH A COASTAL TROUGH...THEN ANOTHER ROUND IN THE LATE AFTERNOON AHEAD OF A COLD FRONT. MODELS ARE IN REASONABLE AGREEMENT INTRODUCING IFR STRATUS/FOG AROUND DAYBREAK IF NOT BEFORE...AND THIS MAKES SENSE GIVEN THE WEAK WARM AIR ADVECTION. THE HRRR MODEL THINKS THAT ILM STANDS THE BEST CHANCE FOR MORNING PRECIP...BUT THE MYRTLES COULD ALSO GET INTO THE ACT. THINK THE MORNING PRECIP WILL GIVE WAY TO MVFR CEILINGS AND SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT WHICH WILL ARRIVE AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PERIODS OF MVFR/IFR CIGS ARE LIKELY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GUSTY NORTH WINDS SUN/MON BEHIND THE COLD FRONT. BECOMING VFR DURING TUE. VFR WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 125 PM SATURDAY...A COASTAL TROUGH WILL BE IN CLOSE PROXIMITY THROUGH TONIGHT AND LIKELY JUST ABOUT ON THE IMMEDIATE COAST AROUND DAYBREAK SAT. NE WINDS ARE EXPECTED TO SHIFT TO THE E OR ESE OVERNIGHT WITH ITS PASSAGE. WIND SPEEDS WILL BE UP TO 10 TO 15 KT LATE THIS EVE...DECREASING TO 10 KT OR LESS OVERNIGHT. SEAS WILL BE 3 TO 4 FT WITH A 8 TO 10 SECOND EASTERLY SWELL PRESENT. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...QUIET MARINE CONDITIONS TO START THE PERIOD...BUT RAPID DETERIORATION IS EXPECTED ON SUNDAY. WEAK COASTAL TROUGH WILL LIFT NORTH ON SATURDAY...WITH WINDS TURNING FROM SE TO SW THROUGH THE AFTN...BUT AT LIGHT SPEEDS. LOW PRESSURE MOVING NORTH OF THE AREA WILL DRAG A COLD FRONT ACROSS THE WATERS SATURDAY NIGHT...AND WINDS WILL TURN ABRUPTLY TO THE NORTH AT 15-20 KTS BY SUNDAY MORNING. SEAS ON SATURDAY WILL BE GENERALLY 2-4 FT REGARDLESS OF WIND DIRECTION...BUT WILL BEGIN TO RISE LATE BEHIND THE COLD FRONT. GALE WATCH HAS BEEN HOISTED FOR THE NC WATERS BEGINNING SUNDAY MORNING...AND THERE IS PRETTY HIGH CONFIDENCE IN A GALE OCCURRING SUNDAY AS A STRONG WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST. THIS WILL CAUSE A TIGHT GRADIENT OVER THE WATERS...AND WIND WILL BECOME NE AT 20-30 KTS ON SUNDAY...WITH FREQUENT GUSTS TO 35 KTS OR MORE EXPECTED ACROSS THE NC WATERS. THERE IS LOWER CONFIDENCE IN GALE-FORCE WINDS ACROSS SC WATERS...BUT AT LEAST A STRONG SMALL CRAFT ADVISORY IS EXPECTED. THESE STRONG WINDS WILL ALSO PUSH SEAS UP TO TO 5-9 FT ON SUNDAY...WITH THE EXCEPTION BEING THE WAVE SHADOWED REGION SW OF BRUNSWICK COUNTY. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...NEXT WEEK WILL NOT BE THE BEST OF TIMES FOR THE MARINE COMMUNITY AS BLUSTERY CONDITIONS AND ELEVATED SEAS WILL CONTINUE. FOR MONDAY A POTENT NORTHERLY FLOW WILL CONTINUE AS LOW PRESSURE MOVES WELL OFF TO THE NORTHEAST AND MASSIVE HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. EXPECT WINDS OF 20-25 KNOTS...POSSIBLY HIGHER WITH CERTAIN SMALL CRAFT CONDITIONS AND POSSIBLY GALES. THE WINDS DO DIMINISH THROUGHOUT THE DAY TO SETTLE AT 10-15 KNOTS BY TUESDAY MORNING. HERE THE WINDS WILL REMAIN THROUGH WEDNESDAY. SEAS WILL BE HIGHEST MONDAY WITH 3-6 FEET DROPPING TO 2-5 FEET TUESDAY AND WEDNESDAY. && .TIDES/COASTAL FLOODING... AS OF 700 PM WEDNESDAY...THE FULL MOON IS ON SATURDAY. WE EXPECT ELEVATED WATER LEVELS DURING THE TIME OF HIGH TIDE THROUGH THE WEEKEND. THE MORNING HIGH TIDE WILL BE HIGHEST AND THIS IS WHEN WE EXPECT THE TIDE TO COME UP WELL ONTO THE BEACH. STRONG NNE WINDS SUNDAY AND SUNDAY NIGHT WILL HELP TO ENHANCE THE ASTRONOMICAL EFFECTS. THE LOWER CAPE FEAR RIVER WILL ALSO EXPERIENCE HIGHER THAN PREDICTED WATER LEVELS AND MAY REACH COASTAL FLOOD ADVISORY CRITERIA DURING THE MORNING HIGH TIDE THROUGH THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR AMZ250-252. && $$ NEAR TERM...RJD/8 SHORT TERM...JDW LONG TERM...SHK AVIATION...DL TIDES/COASTAL FLOODING...RJD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1243 AM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 1242 AM CST SAT DEC 6 2014 CHANGES FOR THIS UPDATE INCLUDE...INCREASED OVERNIGHT LOW TEMPERATURES...INCREASED CLOUD COVER. LOW STRATUS CONTINUES TO BUILD EAST ACROSS NORTH DAKOTA. THIS THICK STRATUS DECK HAS INHIBITED DIURNAL COOLING. THEREFORE...INCREASED OVERNIGHT LOW TEMPERATURES FOR LOCATIONS UNDER THIS CLOUD DECK. SPEAKING OF CLOUDS...INCREASED COVERAGE AND DURATION OF THE CLOUD COVER THROUGH THE MORNING EARLY MORNING HOURS. LATEST SATELLITE TRENDS AND SHORT-TERM GUIDANCE SUGGESTS THIS THICK CLOUD COVER WILL REMAIN ENTRENCHED OVER NORTH DAKOTA UNTIL LATER THIS MORNING WHEN WAA ADVECTION KICKS IN IN ERNEST. A SCATTERED LIGHT WINTRY MIX CONTINUES ACROSS PORTIONS OF SOUTHWEST NORTH DAKOTA WHERE WARMER AIR ALOFT HAS PUSHED NORTH. WILL MONITOR THIS DEVELOPMENT AS ADJUSTMENTS MAY BE NEEDED TO THE PRECIP FORECAST FOR THE EARLY MORNING HOURS. UPDATE ISSUED AT 923 PM CST FRI DEC 5 2014 FOR LATE EVENING UPDATE MAIN CONCERN WAS PRECIPITATION OVER THE FAR SOUTHWEST. LATEST HIGH-RES MODELS WERE HAVING SOME TROUBLE ON PLACEMENT OF PRECIPITATION THIS EVENING...BUT REGIONAL RADAR MOSAIC ALONG WITH BOWMAN ARB RADAR INDICATED VERY LIGHT PRECIPITATION SHIFTING TOWARDS WEST CENTRAL AND SOUTHWEST NORTH DAKOTA. THEREFORE...HAVE SPREAD LOW POPS THROUGH THE SOUTHWEST. NEXT CONCERN WAS PRECIP TYPE AS SOME WARMER AIR ALOFT IS STARTING TO PUSH TOWARDS THE FAR SOUTHWEST. WITH THIS...HAVE ADDED THE MENTION OF POSSIBLE SLEET/FREEZING RAIN...ALTHOUGH CHANCES AND COVERAGE WILL BE VERY LOW. ONLY OTHER CHANGE FOR UPDATE WAS DROPPING LOW TEMPERATURES A BIT OVER THE NORTHWEST/NORTH CENTRAL AS OBBS JUST NORTH OF THE CANADIAN BORDER HAVE ALREADY DIPPED DOWN TOWARDS ZERO. UPDATES HAVE BEEN SENT. UPDATE ISSUED AT 621 PM CST FRI DEC 5 2014 MAIN CHANGE FOR EARLY EVENING UPDATE WAS TO INCREASE CLOUD COVER ACROSS ALL AREAS EXCEPT FAR SOUTH CENTRAL/JAMES RIVER VALLEY AS BROAD AREA CONTINUES TO SHIFT SOUTHEAST. WILL HAVE TO KEEP AN EYE ON TEMPERATURES THROUGH THE EVENING AS WHEREVER THERE ARE BREAKS IN THE CLOUD COVER OVER THE NORTH...THE TEMPERATURE HAS DROPPED QUICKLY. UPDATES HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 CURRENTLY...HIGH PRESSURE OVER NORTHWEST NORTH DAKOTA THIS EARLY AFTERNOON IS FORECAST TO MOVE EAST ACROSS THE FORECAST AREA TONIGHT. IFR STRATUS REMAINS OVER NORTHWEST NORTH DAKOTA FROM CROSBY AND WILLISTON...EAST TO STANLEY...BUT HAVING A HARD TIME MAKING IT MUCH FARTHER EAST THIS AFTERNOON. TEMPERATURES RANGED FROM THE UPPER TEENS-LOW 20S NORTH TO UPPER 20S-LOW 30S SOUTH. MAIN CONCERN FOR THE SHORT TERM PERIOD IS STRATUS/FOG POSSIBILITIES AND POSSIBLE LIGHT PRECIPITATION ACROSS THE NORTH. THE 05 DEC 12 UTC NAM AND MESOSCALE MODELS HAVE BEEN HINTING AT A BAND OF LIGHT PRECIPITATION MOVING ACROSS NORTHERN NORTH DAKOTA LATE TONIGHT INTO SATURDAY MORNING. THE 18 UTC NAM HAS DISPLACED THE PRECIPITATION FARTHER SOUTH...BUT RAP/HRRR HAVE BEEN PRETTY CONSISTENT IN KEEPING VERY LIGHT PRECIPITATION ACROSS THE NORTH. HAVE ADDED SOME SLIGHT CHANCE POPS NORTHWEST AND NORTH CENTRAL LATER THIS EVENING INTO SATURDAY MORNING...TAPERING TO ONLY FLURRIES AS PRECIPITATION MOVES FROM NORTH CENTRAL INTO NORTHEAST ND. HAVE KEPT PRECIPITATION ALL SNOW AS IT LOOKS LIKE THE WARMER TEMPERATURES ALOFT DO NOT ARRIVE UNTIL BEST FORCING HAS ALREADY PASSED...THUS PRECIP SHOULD REMAIN ALL SNOW. MESOSCALE MODELS CONTINUE TO SHOW INCREASING LOW LEVEL MOISTURE ACROSS THE NORTH AND EAST THIS AFTERNOON AND THIS EVENING...THEN POSSIBLY SHIFTING MORE TO THE SOUTHWEST LATER TONIGHT AS SOUTHEAST FLOW KICKS IN ON THE BACK SIDE OF THE SURFACE HIGH. HAVE OPTED TO MENTION PATCHY FOG TONIGHT AS RAP BUFR SOUNDINGS DO SUGGEST FOG MOST AREAS. ALSO HAVE BUMPED UP SKY COVER LATE EVENING THROUGH SATURDAY MORNING. TEMPERATURES ALSO TRICKY AS WE WILL LIKELY SEE A QUICK DROP THIS EVENING EAST WITH RISING TEMPERATURES LATE. PERHAPS A QUICK DROP CENTRAL/WEST WITH RISING TEMPERATURES LATE EVENING INTO THE OVERNIGHT AND THEN DROPPING OFF BY MORNING. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 322 PM CST FRI DEC 5 2014 SATURDAY NIGHT THROUGH SUNDAY NIGHT...AN UPPER LEVEL LOW/SHARP TROUGH WITH AN ASSOCIATED SURFACE COLD FRONT WILL PUSH ACROSS WESTERN AND CENTRAL NORTH DAKOTA SUNDAY INTO SUNDAY NIGHT. SOUTH TO SOUTHWESTERLY FLOW AHEAD OF THIS SYSTEM WILL ALLOW FOR WARMING THROUGH SUNDAY MORNING. THE H85 BAROCLINIC ZONE BEGINS TO PUSH ACROSS THE FAR WEST BY 18Z AND THEN SHIFTS INTO CENTRAL NORTH DAKOTA SUNDAY AFTERNOON/EVENING. STILL SOME THREAT OF A WINTRY MIX ACROSS NORTHERN NORTH DAKOTA...BUT IT APPEARS THE BETTER CHANCE FOR PRECIPITATION MAY OCCUR SUNDAY EVENING INTO SUNDAY NIGHT ACROSS NORTHERN NORTH DAKOTA...ASSOCIATED WITH A WEAK/NARROW TROWAL PER GFS H7-H5 EQUIVALENT POTENTIAL TEMPERATURE. AMOUNTS LOOK VERY LIGHT...PERHAPS A TENTH OR TWO OF AN INCH OF SNOW. WEST TO NORTHWEST WINDS INCREASE IN THE WEST DURING THE AFTERNOON WITH THE STRONGEST WINDS NOT ARRIVING UNTIL SUNDAY NIGHT FOR CENTRAL NORTH DAKOTA. EXPECT 20 TO 35MPH WINDS DEVELOPING BEHIND THIS SYSTEM. WITH LIMITED SNOW SHOWERS AND QPF...AT THIS TIME HAVE NOT MENTIONED ANY BLOWING SNOW. MONDAY THROUGH FRIDAY...BRISK NORTHWEST WINDS CONTINUE DURING THE DAY MONDAY BUT ABATE MONDAY EVENING. COLDER MONDAY AFTERNOON WITH HIGHS 20 NORTHEAST TO MID 30S FAR SOUTHWEST. THEREAFTER A PROGRESSIVE PATTERN ENSUES WITH NO SIGNIFICANT SHORTWAVES FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. A WARMING TREND IS STILL IN THE FORECAST WITH HIGHS 35F TO 45F WEDNESDAY THROUGH FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1242 AM CST SAT DEC 6 2014 IFR CIGS WILL CONTINUE OVER NORTH CENTRAL NORTH DAKOTA THROUGH MUCH OF THE NIGHT...AFFECTING KMOT. ELSEWHERE VFR TO MVFR CIGS CAN BE EXPECTED. PATCHY FOG MAY DEVELOP OVERNIGHT AT SOME OR ALL TERMINALS...WITH KMOT/KJMS MOST LIKELY TO SEE FOG. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AJ SHORT TERM...TWH LONG TERM...KS AVIATION...AJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1119 PM CST FRI DEC 5 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 304 PM CST FRI DEC 5 2014 ALTHOUGH VISIBILITY HAS IMPROVED...FOG CONTINUES TO RESIDE THROUGH NORTHWEST IOWA THIS AFTERNOON...SO THE BIGGEST CHALLENGE TONIGHT REMAINS HOW QUICKLY FOG ERODES AS DRIER AIR FILTERS IN BEHIND THE SURFACE TROUGH PUSHING ACROSS THE REGION. WATCHING THE TRENDS THROUGH THE AFTERNOON...VISIBILITIES HAVE QUICKLY IMPROVED AS THE WINDS TRANSITIONED TO NORTHERLY BEHIND THE TROUGH AND THE DRIER AIR DRAINED IN. USING THAT AND RAP 925 MB RH FIELDS WHICH HAVE ALSO CORRELATED WELL WITH THE FOG...HAVE THE FOG LINGERING THROUGH PORTIONS OF NORTHWEST IOWA THROUGH THE EVENING THEN SLOWLY ERODING FROM THE NORTH AND WEST AS DRIER AIR TAKES OVER DURING THE NIGHT. COLDER AIR WILL ALSO FILTER SOUTH OVERNIGHT...WITH LOWS BOTTOMING OUT AROUND 10 THROUGH THE HIGHWAY 14 CORRIDOR TO THE UPPER TEENS THROUGH THE MISSOURI RIVER VALLEY. SURFACE HIGH PRESSURE SETTLES INTO THE REGION ON SATURDAY...SO SHOULD SEE SOME SUN ALONG WITH RELATIVELY LIGHT WINDS DURING THE DAY WITH A WEAK GRADIENT EXISTING ACROSS THE REGION. WITH THERMAL PROFILES A LITTLE COOLER HIGHS WILL RANGE FROM THE LOWER 30S NORTH TO UPPER 30S SOUTH. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 304 PM CST FRI DEC 5 2014 THE PRIMARY FORECAST CONCERNS IN THE MEDIUM AND SHORT RANGE CONTINUE TO FOCUS ON LIGHT PRECIPITATION CHANCES SUNDAY AND WARMUP INTO NEXT WEEK/WEEKEND. SUNDAY...MODELS STILL ON TRACK BRINGING TWO PIECES OF SHORTWAVE ENERGY INTO THE REGION LATE SATURDAY NIGHT AND INTO SUNDAY. THE FIRST WAVE WILL LIFT NORTHWARD FROM THE SOUTHWESTERN US WITH THE SECOND WAVE DIPPING SOUTHEAST FROM THE PACIFIC NORTHWEST. AGAIN...MOISTURE REMAINS RATHER SHALLOW IN NATURE AS THESE WAVES MOVE THROUGH BUT AM ANTICIPATING A NARROW CORRIDOR OF LIGHT FREEZING RAIN/DRIZZLE DEVELOPING NEAR DAYBREAK ALONG AND WEST OF I-29. WHILE THE ATMOSPHERIC PROFILE LACKS ICE CRYSTALS FOR MOST OF THE EVENT...THERE COULD BE A BRIEF WINDOW OF SATURATION EARLY IN THE AFTERNOON WHICH WOULD OWE TO SLEET INTRODUCTION ESPECIALLY IN THE NE ZONES. THE PRECIPITATION SHOULD BE LIGHT ENOUGH TO AVOID ANY MAJOR ICING CONCERNS...ESPECIALLY SINCE SFC TEMPERATURES WILL CONTINUE TO RISE THROUGH THE MORNING AND SHOULD CLIMB ABOVE FREEZING IN THE AFTERNOON. NEXT WEEK...SLIGHT MODEL DIFFERENCES CONTINUE FOR MUCH OF NEXT WEEK WITH BOTH MAJOR EXTENDED RANGE MODELS SHOWING INCREASED RIDGING ACROSS THE CONUS INTO NEXT WEEKEND. TEMPERATURES WILL COOL SLIGHTLY BEHIND SUNDAYS DEPARTING TROUGH...BUT STILL AVERAGE NEAR OR SLIGHTLY ABOVE SEASONAL NORMALS. FAIRLY SUBSTANTIAL DIFFERENCES PERSIST IN THE HANDLING OF SHORTWAVE ENERGY MOVING THROUGH THE PACIFIC NORTHWEST ON MONDAY. ECMWF KEEPS THIS ENERGY WELL NORTH OF THE CWA...MEANWHILE THE GFS PULLS THE WAVE THROUGH THE CENTRAL PLAINS. THE END RESULTS COULD BE SUBSTANTIAL DIFFERENT FOR WEDNESDAY- FRIDAY. SHOULD THE GFS SOLUTION VERIFY...THE RESULT WOULD BE INCREASED CLOUD COVER...FOG...AND SLIGHTLY COOLER TEMPS IN THE LOCAL AREA. ON THE FLIPSIDE...THE MORE AMPLIFIED ECMWF SOLN COULD SUGGEST VERY WARM TEMPERATURES THURSDAY AND INTO THE WEEKEND. FOR TODAY...PREFERENCES CONTINUE TO FALL TOWARDS THE ECMWF...BUT WILL HEDGE A BIT TOWARDS THE OTHER CAMP OF SOLNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1119 PM CST FRI DEC 5 2014 MONITORING A QUICK END ON KSUX AREA WEBCAMS TO THE VLIFR AND IFR CONDITIONS AROUND KSUX WHICH ARE EXPECTED TO BE OUT OF THE KSUX AREA BY ISSUANCE OF THE 06Z TAFS. MOISTURE WILL KEEP THREAT OF SOME MVFR VISIBILITIES AROUND THE KSUX AREA INTO EARLY MORNING AS NORTHERLY WINDS DIMINISH. FOR KFSD...MORE LIKELY TO GET ONLY A PERIOD OF SHALLOW VALLEY FOG...WITH DEEPER DRY LAYER ALOFT. TOWARD THE END OF THE TAF PERIOD...MAY SEE RESURGENCE IN THE LIFR CEILINGS AS FLOW TURNS TO THE SOUTHEAST. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...DUX AVIATION...CHAPMAN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1011 PM MST FRI DEC 5 2014 .UPDATE... ISSUED AT 725 PM MST FRI DEC 5 2014 STALLED LL BAROCLINIC ZONE ACROSS THE FAR NORTH WILL INTERACT WITH A PASSING MID LEVEL IMPULSE THIS EVENING...POSSIBLY SUPPORTING A FEW LIGHT SHOWERS ACROSS FAR NW SD. HAVE ADDED A SLIGHT CHANCE FOR PRECIP THERE...OPTING FOR A WINTRY MIX GIVEN WARM WEDGE ALOFT. OTHERWISE...SUFFICIENT LL MOISTURE AT THE SFC MAY SUPPORT PATCHY AREAS OF FOG LATER TONIGHT ACROSS WESTERN SD. HOWEVER...ENSUING SFC PRESSURE FALLS PER LEE SIDE TROUGHING WILL SUPPORTING INCREASING LL FLOW...INCREASING TURBULENT MIX DOWN OF DRY AIR. THIS WILL LIKELY LIMIT COVERAGE OF ANY FOG...ESP AWAY FROM VALLEYS. HAVE TRIMMED DOWN FOG MENTION AND RELEGATED MENTION TO PATCHY. && .SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT ISSUED AT 207 PM MST FRI DEC 5 2014 UPPER LEVEL ANALYSIS SHOWS A RIDGE OVER THE WESTERN CONUS...WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS. CANADIAN SURFACE HIGH IS MOVING SOUTHWARD INTO MT/ND. SKIES ARE PARTLY CLOUDY...WITH GENERALLY LIGHT WINDS AND TEMPS IN THE UPPER 30S AND 40S. LIGHT WINDS WILL BECOME SOUTHEASTERLY TONIGHT AS THE SURFACE HIGH CROSSES ND...BRINGING MOISTURE INTO THE AREA. SEVERAL MODELS ARE STILL HINTING AT SOME FOG SETTING UP AROUND THE AREA. THE HRRR AND RAP ARE SHOWING LOW CEILINGS ACROSS THE SD PLAINS DEVELOPING AFTER MIDNIGHT...AND LATEST RUNS ALSO HAVE FOG WRAPPING AROUND THE SOUTHERN HILLS INTO NORTHEAST WY. MEANWHILE THE NAM HAS THE BEST CHANCES FOR FOG AROUND THE HILLS AND INTO NORTHEAST WY...NOT SO MUCH ON THE SD PLAINS. THE NAM SEEMS TO BE OVERESTIMATING MOISTURE LATELY...AND SINCE WINDS IN NORTHEAST WY LOOK A LITTLE STRONGER OVERNIGHT...HAVE MORE UNCERTAINTY ABOUT FOG DEVELOPMENT THERE. DECREASED AREAS OF FOG TO PATCHY ACROSS NORTHEAST WY...KEEPING AREAS OF FOG JUST EAST OF THE HILLS. COULD ALSO BE SOME PATCHY FOG IN SURROUNDING AREAS ACROSS THE SD PLAINS. AS THE SURFACE HIGH MOVES SOUTHEAST OVERNIGHT...COLD AIR WILL ADVECT INTO THE EASTERN CWA. LOWS WILL RANGE FROM THE TEENS ACROSS NORTH CENTRAL/NORTHWEST SD TO THE UPPER 20S IN NORTHEAST WY. SOUTHERLY WINDS WILL BECOME BREEZY BY LATE SATURDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE HIGH PRESSURE TO THE EAST AND THE INCOMING LOW. EXPECT FOG TO DISSIPATE BY MID-MORNING. THERE IS SOME UNCERTAINTY WITH TEMPS ON SATURDAY...AS MODELS HAVE A 10-DEGREE SPREAD FOR HIGHS IN SOME PLACES. WITH SOUTHERLY BOUNDARY-LAYER WINDS AND WARM AIR ADVECTION...KEPT TEMPS MILD...IN THE MID 30S NORTH AND EAST TO THE UPPER 40S FARTHER WEST. LOWS SATURDAY NIGHT WILL BE IN THE 20S TO LOWER 30S. .LONG TERM...SUNDAY THROUGH FRIDAY ISSUED AT 207 PM MST FRI DEC 5 2014 MODELS ARE IN GOOD AGREEMENT DURING THE EXTENDED PERIOD...WITH RELATIVELY HIGH PREDICTABILITY THROUGH AT LEAST WEDNESDAY. IN THE MEAN...THERE WILL BE A LONG-WAVE TROUGH OFF THE WEST COAST WITH A LONG-WAVE RIDGE NEAR THE CNTRL CONUS. ON SUNDAY A SHORT-WAVE TROUGH WILL MOVE ACROSS THE FAR NRN PLAINS AND THROUGH THE L/W RIDGE...BRINGING A COLD FRONT AND NORTHWEST WIND SHIFT ACROSS THE CWA. THIS WILL BRING SCT SHRASN TO THE BLKHLS. ON MONDAY THROUGH WEDNESDAY THE RIDGE REBOUNDS...BUT WITH A WEAK SHORT- WAVE TROUGH SLOWLY MOVING ACROSS THE NRN PLAINS. THIS IS NOT EXPECTED TO BRING ANY PRECIP TO THE CWA GIVEN THE LIMITED FORCING FOR ASCENT AND LACK OF LOW- TO MID-LEVEL MOISTURE. ON THURSDAY AND FRIDAY...THE LONG-WAVE TROUGH MOVES INTO THE ERN HALF OF THE CONUS WITH SOUTHWEST FLOW ALOFT DEVELOPING ACROSS THE CWA IN RESPONSE TO A DEEP UPPER LOW COMING ONSHORE NEAR CA. THE GFS SEEMS A BIT AGGRESSIVE WITH THIS LOW...SO HAVE KEPT THE FORECAST DRY THROUGH FRIDAY. NEVERTHELESS...THERE ARE INDICATIONS THAT A BIG STORM COULD BE LOOMING ON THE HORIZON FOR LATE NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1010 PM MST FRI DEC 5 2014 VFR CONDITIONS EXPECTED THROUGH THE PERIOD MOST PLACES. INCREASED BL MOISTURE WITH A PERIOD OF LIGHT WINDS AND CLEAR SKIES MAY SUPPORT PATCHY/AREAS OF FOG TONIGHT. HOWEVER...INCREASING LL SOUTHERLY FLOW AND LIMITED MOISTURE ADVECTION SHOULD LIMIT COVERAGE OF ANY FOG/STRATUS. GIVEN LOW PROBS/CONFIDENCE HAVE OPTED TO LEAVE OUT OF TERMINALS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ UPDATE...JC SHORT TERM...POJORLIE LONG TERM...BUNKERS AVIATION...JC
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1158 PM CST FRI DEC 5 2014 .AVIATION... A COLD FRONT HAS MOVED THROUGH NORTH AND CENTRAL TEXAS AS OF 0550Z. NORTH TO NORTHEAST WINDS AROUND 10 KNOTS WILL PREVAIL THROUGH THE PERIOD. MVFR STRATUS HAS MOVED INTO THE METROPLEX AND WILL MOVE INTO WACO AROUND 09Z. CEILINGS MAY FALL INTO THE IFR CATEGORY 10-15Z. THE BROKEN TO OVERCAST CLOUDS ARE EXPECTED TO BECOME SCATTERED AROUND 18Z SATURDAY. MVFR CEILINGS SHOULD DEVELOP AGAIN AROUND 06Z SUNDAY. 58 && .UPDATE... COLD FRONT IS ABOUT HALFWAY THROUGH THE CWA THIS EVENING BUT MOST OF THE SHOWER ACTIVITY HAS DIMINISHED AS UPPER TROUGH PULLS FARTHER AWAY TO THE EAST. OUTSIDE OF AN ISOLATED SHOWER RIGHT ALONG THE FRONT...MOST AREAS WILL NOT SEE ANY RAIN. LOWERED POPS FOR THE REMAINDER OF THE EVENING AND CONFINED THEM TO A NARROW BAND RIGHT ALONG THE FRONT OVER THE EASTERN COUNTIES. OTHERWISE...ONLY SOME MINOR DOWNWARD TWEAKS IN LOW TEMPERATURES WERE NEEDED ACROSS THE NORTH AND NORTHWEST COUNTIES. DUNN && .PREV DISCUSSION... /ISSUED 339 PM CST FRI DEC 5 2014/ FOR TODAY...THE ONLY SIGNIFICANT CHANGE TO THE FORECAST FROM THE MORNING UPDATE WAS TO INCREASE POPS SLIGHTLY ALONG AND SOUTHEAST OF THE FORECAST POSITION OF THE COLD FRONT ACROSS THE CWA THROUGH TONIGHT. EARLY AFTERNOON RUNS OF THE HRRR CONSISTENTLY ADVERTISE A SCATTERED LINE OF SHOWERS DEVELOPING ALONG THE LEADING EDGE OF THE COLD FRONT AS IT MOVES ACROSS THE CWA. AT 20Z/2PM...THE SURFACE OBSERVATIONS INDICATED THAT THE LEADING EDGE OF THE COLD FRONT WAS LOCATED ALONG A LINE FROM ARDMORE TO BOWIE TO BRECKENRIDGE. EARLY AFTERNOON VISIBLE SATELLITE IMAGERY SHOWED A THIN LINE OF CUMULUS ORGANIZING ALONG THE FRONT...SUPPORTING THE HRRR FORECAST FOR STRONGER LIFT AND BETTER RAIN SHOWER CHANCES IN THE IMMEDIATE VICINITY OF THE FRONT. DESPITE THE INCREASE IN RAIN CHANCES IN THE SHORT TERM FORECAST...CONTINUE TO THINK CHANCES OF LIGHTNING ARE LOW. 19Z AIRCRAFT SOUNDINGS FROM KDFW AND KDAL AIRPORTS CONTINUE TO SHOW MID-LEVEL LAPSE RATES THAT ARE TOO STABLE TO SUPPORT FREE CONVECTION. LAPSE RATES HAVE INCREASED A BIT FROM 12Z...LIKELY DUE FROM DYNAMIC LIFT ASSOCIATED WITH A SHORTWAVE TROUGH LOCATED OVER OKLAHOMA EARLY THIS AFTERNOON ACCORDING TO WATER VAPOR SATELLITE IMAGERY. HOWEVER DUE TO THE POSITION OF THE SHORTWAVE TROUGH...THINK THAT THE EFFECTS OF DYNAMIC LIFT ON OUR MID-LEVEL LAPSE RATES HAVE ALREADY OCCURRED. AS A RESULT...LEFT PRECIPITATION ALONG THE FRONT THUNDERSTORM FREE THROUGH TONIGHT. WILL CERTAINLY CONTINUE TO MONITOR AIRCRAFT OBSERVATIONS THROUGH THIS EVENING...AND WILL UPDATE THE FORECAST IF IT LOOKS LIKE THUNDER IS BECOMING MORE LIKELY. SATURDAY...THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE ENTIRE FORECAST AREA BY SATURDAY MORNING...LEAVING COOLER AND MUCH DRIER AIR IN PLACE ACROSS THE REGION. ALTHOUGH THE COLD FRONT DOES NOT REPRESENT A STRONG CANADIAN AIRMASS...AFTER TODAY`S TEMPERATURES IN THE MID TO UPPER 70S...IT WILL CERTAINLY BE NOTICEABLY COOLER TOMORROW BEHIND THE FRONT. HIGHS ARE EXPECTED TO TOP OUT NEAR 60 DEGREES FOR MOST LOCATIONS...VERY CLOSE TO NORMAL HIGHS FOR THIS TIME OF YEAR. BETWEEN LOW-LEVEL DRY AIR ADVECTION BEHIND THE FRONT AND SHORTWAVE RIDGING ALOFT...MAINTAINED A DRY FORECAST FOR SATURDAY. SUNDAY...A RELATIVELY FAST MOVING SHORTWAVE TROUGH...CURRENTLY LOCATED ABOUT 800 MILES WEST OF BAJA CALIFORNIA...IS EXPECTED TO MOVE OVER THE SOUTHERN PLAINS SUNDAY AFTERNOON. WITH A LOW-LEVEL COOL AIRMASS STILL IN PLACE ACROSS THE CWA BEHIND TODAY`S FRONT...ALL MODEL GUIDANCE INDICATES THAT THIS SHORTWAVE TROUGH WILL RESULT IN STRONG WARM AIR ADVECTION OVER THE CWA ON SUNDAY. WARM AIR ADVECTION OVER THE COOL LOW-LEVEL AIRMASS DOES REPRESENT PERSISTENT LIFT...HOWEVER PRECIPITATION PROSPECTS FOR THE REGION LOOK VERY LIMITED AT THIS TIME. DESPITE NEARLY ALL MODELS SHOWING THE PERSISTENT LIFT ON SUNDAY...THE PROSPECTS FOR MOISTURE RETURN LOOK VERY LIMITED...AND FOCUSED ON LOCATIONS JUST WEST AND SOUTH OF THE CWA. AS A RESULT...WENT AHEAD AND BUMPED POPS DOWN 10 PERCENT ACROSS THE ENTIRE AREA THROUGHOUT THE DAY ON SUNDAY. THINK THAT OUR BEST CHANCES FOR LIGHT RAINFALL MAY BE WHEN THE SHORTWAVE TROUGH MOVES DIRECTLY OVERHEAD SUNDAY AFTERNOON. MODELS SHOW A BAND OF RELATIVELY STRONG MID-LEVEL FRONTOGENETIC FORCING MOVING OVER THE CWA RIGHT OUT AHEAD OF THE SHORTWAVE ON SUNDAY. THIS WILL LIKELY RESULT IN SOME ELEVATED PRECIPITATION...HOWEVER THE LOW-LEVEL AIRMASS LOOKS DRY ENOUGH THAT MOST OF THIS SHOULD EVAPORATE BEFORE REACHING THE SURFACE. AT ANY RATE...THE END RESULT WAS THAT ISOLATED RAIN SHOWERS WERE INCLUDED IN THE FORECAST EVEN WHERE POPS ARE AS LOW AS 10 PERCENT TO ACCOUNT FOR THIS VIRGA/LIGHT RAIN POTENTIAL. MONDAY INTO TUESDAY...IN GENERAL...A REINFORCING SHOT OF COOL AND DRY AIR WILL BUILD INTO THE AREA BEHIND SUNDAY`S SHORTWAVE TROUGH KEEPING US DRY ACROSS NORTH TEXAS FOR EARLY NEXT WEEK. THE LARGE SCALE UPPER AIR PATTERN IS EXPECTED TO BE DOMINATED BY LARGE TROUGHS OVER THE FAR EAST AND WEST COASTS...RESULTING IN BROAD RIDGING OR NEARLY ZONAL FLOW OVER THE CENTRAL PORTION OF THE COUNTRY. THIS PATTERN ALSO GENERALLY FAVORS DRY WEATHER FOR THE CWA...HOWEVER PERSISTENT WESTERLY FLOW ALOFT OVER THE CONUS ROCKIES WILL RESULT IN LEE-SIDE TROUGHING INCREASING IN INTENSITY THROUGHOUT THE WEEK. WITH LEE-SIDE TROUGHING DEVELOPING AND A COOL AIRMASS IN PLACE...WE WILL ONCE AGAIN HAVE A SITUATION WHERE WE HAVE SOUTHERLY FLOW ALOFT IMPINGING ON A COOL LOW-LEVEL AIRMASS NEAR THE SURFACE. THIS WILL RESULT IN PERSISTENT...ALBEIT WEAK...LIFT AND MOISTURE RETURN BY TUESDAY AFTERNOON. BACKED OFF ON POPS A BIT FROM THE PREVIOUS FORECAST ON TUESDAY...HOWEVER MAINTAINED SOME 20 POPS OVER THE FAR WESTERN CWA TUESDAY AFTERNOON...NEAREST TO THE LOW-LEVEL MOISTURE RETURN CONSISTENTLY ADVERTISED IN MEDIUM RANGE GUIDANCE. WEDNESDAY...MODELS ADVERTISE THAT THE UPPER LEVEL PATTERN WILL AMPLIFY WITH RIDGING BUILDING OVER THE CONUS ROCKIES IN RESPONSE TO A STRONG UPPER TROUGH BUILDING EASTWARD...FARTHER ON SHORE THE WESTERN CONUS COAST. THIS RESULTS IN NORTHWEST FLOW ALOFT OVER THE REGION ON WEDNESDAY...IN WHICH MODELS HAVE BEEN CONSISTENTLY SENDING A STRONG BUT COMPACT SHORTWAVE TROUGH SOUTHEAST THROUGH THE CWA OVER THE PAST COUPLE OF DAYS. THIS TROUGH IS EXPECTED TO REMAIN WELL NORTH OF NORTH TEXAS...BUT SHOULD HELP SPREAD SOME OF THE MOISTURE RETURN FROM WEST TEXAS EASTWARD OVER THE CWA ON WEDNESDAY. IF MOISTURE DOES SPREAD EAST AS ADVERTISED AND LOW- LEVEL WARM AIR ADVECTION AND ISENTROPIC LIFT CONTINUES... LIGHT RAIN SHOWERS WILL LIKELY SPREAD ACROSS THE ENTIRE CWA ON WEDNESDAY. BECAUSE LIFT IS EXPECTED TO REMAIN WEAK...RAIN SHOWERS SHOULD BE SPOTTY/HIT-AND-MISS ON WEDNESDAY. THURSDAY AND FRIDAY...MODELS INDICATE THAT LOW-LEVEL WARM AIR ADVECTION PERSISTS...HOWEVER MODELS ARE ALSO BRINGING THE UPPER LEVEL RIDGE OUT FROM THE CONUS ROCKIES AND OVER THE GREAT PLAINS FOR THE LATTER PART OF THE WEEK. DESPITE PERSISTENT LOW-LEVEL LIFT...WILL FAVOR THE UPPER LEVEL RIDGING IN THIS FORECAST AND KEEP THURSDAY AND FRIDAY DRY FOR NOW AS MID AND UPPER LEVEL FORCING SHOULD BE DOMINATED BY SUBSIDENCE. NEXT WEEKEND...MODELS ARE DEFINITELY STRUGGLING WITH RUN TO RUN AND MODEL TO MODEL CONSISTENCY WITH REGARDS TO THE EVOLUTION OF THE STRONG WEST COAST UPPER TROUGH. HOWEVER...MODELS HAVE BEEN CONSISTENTLY BRINGING THIS TROUGH OVER THE PLAINS NEXT WEEKEND...WHICH MAY RESULT IN SOME DECENT RAIN CHANCES FOR THE REGION. THIS IS CURRENTLY BEYOND THE VALID FORECAST PERIOD...BUT IT IS A SYSTEM THAT WE WILL BE KEEPING A CLOSE EYE ON IN THE COMING DAYS. CAVANAUGH && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 49 61 44 57 43 / 5 5 5 10 10 WACO, TX 51 63 46 57 43 / 10 10 10 20 20 PARIS, TX 49 60 42 56 39 / 20 10 5 10 10 DENTON, TX 45 60 42 56 41 / 5 5 5 10 5 MCKINNEY, TX 45 60 42 57 40 / 5 5 5 10 10 DALLAS, TX 50 61 45 56 44 / 5 5 5 10 10 TERRELL, TX 49 62 44 58 40 / 10 5 5 10 10 CORSICANA, TX 52 63 45 59 43 / 20 10 10 20 20 TEMPLE, TX 51 64 46 58 44 / 10 10 10 20 20 MINERAL WELLS, TX 45 60 42 56 42 / 0 5 10 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 58/91
AREA FORECAST DISCUSSION
NWS PORTLAND OR
851 PM PST FRI DEC 5 2014 .SYNOPSIS...THE FIRST IN A SERIES OF WETTER...WARMER...BREEZIER STORM SYSTEMS WAS MOVING INTO NORTHWEST OREGON AND SOUTHWEST WASHINGTON TONIGHT...WITH SOME LINGERING COLD AIR IN THE UPPER HOOD RIVER VALLEY AND SHELTERED VALLEYS OF THE SOUTH WASHINGTON CASCADES. HOWEVER...TEMPERATURES SHOULD MODERATE AS THE FAIRLY STRONG FRONT MOVES THROUGH LATE TONIGHT AND EARLY SATURDAY. SNOW LEVELS WILL LOWER TO AROUND 4500 FEET LATE TONIGHT AND SATURDAY MORNING IN THE CASCADES...WITH THE BEST CHANCE OF DECENT ACCUMULATING SNOWS IN THE SOUTH WASHINGTON CASCADES. A BRIEF UPPER RIDGE WILL BRING DRYING BUT ALSO SOME VALLEY FOG SATURDAY NIGHT AND SUNDAY. THE NEXT SYSTEM MOVES IN SUNDAY NIGHT AND MONDAY...WITH A SERIES OF WETTER AND WINDIER SYSTEMS MONDAY NIGHT INTO THURSDAY. && .SHORT TERM...TONIGHT THROUGH MONDAY...THE FIRST IN A SERIES OF DECENT FRONTS WAS SPREADING IN FROM THE SOUTHWEST THIS EVENING...AND WILL COVER THE AREA OVERNIGHT. STRONG EAST WINDS THROUGH THE GORGE AND THE RESULTANT COLD AIR DAMMING ALONG THE EAST SLOPES OF THE CASCADES INDICATES ONE MORE ROUND OF SOME FREEZING RAIN IN THE UPPER HOOD RIVER VALLEY...THE EASTERN VALLEYS OF SKAMANIA COUNTY...AND POSSIBLY EVEN NEAR HOOD RIVER AND THE EAST SLOPES OF MOUNT HOOD. THE FRONT MOVES THROUGH BY 12Z AND THE MODELS INDICATE THE AIR MASS SHOULD MODERATE AROUND THAT TIME WITH A DECREASING CHANCE OF FREEZING RAIN. HOWEVER...THERE IS A CIRCULATION CENTER ALONG THE FRONT ASSOCIATED WITH THE MAIN UPPER LEVEL VORTICITY THAT MOVES THROUGH BEHIND THE FRONT LATE TONIGHT AND SATURDAY MORNING. THIS SHOULD BRING MORE SHOWERS TO THE AREA...AND POSSIBLY EVEN A THUNDERSTORM. THE MODELS ARE FOCUSING THE MAIN POST FRONTAL BAND OF PRECIPITATION SATURDAY TO BE LOCATED FROM THE CENTRAL OREGON COAST RANGE TO THE SOUTH WASHINGTON CASCADES. QPF LATE TONIGHT AND SATURDAY MORNING IN THE SOUTH WASHINGTON CASCADES SUPPORT SNOW ADVISORY TYPE SNOW AMOUNTS... PERHAPS 4 TO 8 INCHES. HAVE THUS CONVERTED THE FREEZING RAIN ADVISORY FOR THE SOUTH WASHINGTON CASCADES TO A WINTER WEATHER ADVISORY FOR FREEZING RAIN AND THEN SNOW TO REFLECT THIS TRANSITION. HAVE KEPT THE FREEZING RAIN ADVISORY FOR THE UPPER HOOD RIVER VALLEY...AND WILL NEED TO MONITOR WHETHER IT GETS COLD ENOUGH NEAR HOOD RIVER TO GET ANY FREEZING RAIN THAT REQUIRES AN ADVISORY THERE LATER TONIGHT. THE SHOWERS SHOULD EASE SATURDAY AFTERNOON AS THE ONSHORE FLOW BEHIND THE DEPARTING SYSTEM WEAKENS...THEN AN UPPER RIDGE BRIEFLY BUILDS INTO THE PACIFIC NORTHWEST SATURDAY NIGHT AND SUNDAY FOR DRYING. BUT THIS WILL LIKELY LEAD TO AREAS OF FOG DEVELOPING SATURDAY NIGHT AND CONTINUING THROUGH AT LEAST SUNDAY MORNING AND POSSIBLY INTO THE AFTERNOON...ESPECIALLY IN AREAS AWAY FROM THE GORGE. THE NEXT SYSTEM IS EXPECTED TO APPROACH AGAIN FROM THE SOUTHWEST LATE SUNDAY BUT MAINLY IMPACT THE AREA SUNDAY NIGHT INTO MONDAY. THIS SYSTEM SHOULD GIVE US ANOTHER SHOT OF PRECIPITATION...BUT IT APPEARS TO WEAKEN A BIT AFTER HITTING NORTHERN CALIFORNIA FIRST AND THEN LIFTING NORTHWARD THROUGH OREGON. THE NEXT SERIES OF MUCH STRONGER...WETTER...AND WINDY SYSTEMS APPEARS HEADED TO OUR AREA IN THE MID WEEK PERIOD NEXT WEEK. TOLLESON .LONG TERM...TUESDAY THROUGH FRIDAY...NOT MUCH CHANGE TO THE OVERALL THINKING FOR THE EXTENDED FORECAST PERIOD. POPS WERE HELD ABOVE CLIMO FOR MUCH OF THE FORECAST. A MORE COMPACT AND ENERGETIC STORM SYSTEM LOOKS LIKE IT WILL IMPACT THE AREA ON TUESDAY...BUT WHETHER OR NOT HIGH WINDS WILL SURFACE ON THE COAST REMAINS UNCERTAIN THIS FAR OUT. A SECOND LOW PRESSURE SYSTEM DEVELOPING IN THE NORTHEAST PACIFIC WILL SEND ANOTHER FRONT INTO THE REGION TOWARDS MIDWEEK...BUT AS THE UPPER LEVEL JET PLOWS SOUTH OF THE REGION...THE FRONT WILL PIVOT MORE LONGITUDINALLY AS IT PUSHES THROUGH THE REGION. THIS SHOULD ACT TO HELP QPF TOTALS IN THE VALLEY...BUT PERHAPS CUT DOWN ON THE RAIN TOTALS IN THE COAST RANGE AND CASCADES...AND HELP EASE ANY FLOOD CONCERNS. ONCE THIS FRONT PUSHES THROUGH THE REGION...SNOW LEVELS SHOULD LOWER AND ADDITIONAL ONSHORE FLOW SHOULD BRING PERIODS OF SHOWERS TO THE AREA...LIKELY IN THE FORM OF SNOW ABOVE 4000 TO 5000 FT. HOWEVER...WITH THE MAIN JET AND UPPER LEVEL SUPPORT DIGGING WELL TO OUR SOUTH...BIG MOUNTAIN SNOWS APPEAR UNLIKELY. /NEUMAN && .AVIATION...IFR FOG AND STRATUS HAVE PERSISTED INTO THIS EVENING FOR THE SOUTHERN WILLAMETTE VALLEY. OTHERWISE CONDITIONS ARE MOSTLY VFR ACROSS THE REGION AT CURRENT. HOWEVER...RAIN IS INCREASING FROM THE SW IN ASSOCIATION WITH AN APPROACHING PACIFIC FRONTAL SYSTEM. EXPECT A PERIOD OF MVFR CONDITIONS WITH A FEW POCKETS OF IFR AS THE MODERATE RAIN BAND MOVES THROUGH LATER THIS EVENING AND OVERNIGHT. THE MAIN RAIN BAND SHOULD BE THROUGH BY 12Z...WITH CONDITIONS GRADUALLY IMPROVING THEREAFTER. THERE WILL BE PLENTY OF SHOWERS REMAINING THROUGH TOMORROW AFTERNOON...ESPECIALLY FURTHER NORTH AND ALONG THE COAST. THERE MAY BE PERIODS OF MVFR IN ANY HEAVIER SHOWERS THROUGH ABOUT MIDDAY. THEN EXPECT MOSTLY VFR CONDITIONS FOR THE AFTERNOON. PARTIALLY CLEARING SKIES SHOULD ALLOW FOG TO BEGIN FORMING BY LATER TOMORROW EVENING. GUSTY EASTERLY WINDS THROUGH THE COLUMBIA RIVER GORGE INTO KTTD SHOULD BEGIN TO EASE AFTER MIDNIGHT. KPDX AND APPROACHES...A BAND OF MODERATE RAIN WILL MOVE THROUGH THE TERMINAL LATER THIS EVENING AND OVERNIGHT. EXPECT A PERIOD OF MVFR CONDITIONS DURING THIS TIME. THE RAIN BAND MOVES THROUGH BY 11Z OR 12Z. SHOWERS CONTINUE MUCH OF THE DAY...WITH MVFR CONDITIONS POSSIBLE THROUGH THE MORNING DURING ANY HEAVIER SHOWERS. PYLE && .MARINE...A PACIFIC FRONTAL SYSTEM WILL MOVE THROUGH THE WATERS TONIGHT...BRINGING A PERIOD OF SOLID SMALL CRAFT ADVISORY WINDS AND CHOPPY SEAS. WINDS WILL GRADUALLY PICK UP OVER THE NEXT SEVERAL HOURS...WITH THE STRONGEST WINDS EXPECTED AFTER MIDNIGHT AS THE SURFACE TROUGH MOVES THROUGH THE WATERS. THE LATEST FCST MODELS CONTINUE TO INDICATE THAT A FEW LOW END GALE FORCE GUSTS ARE POSSIBLE OVER THE NEAR SHORE WATERS AND RIGHT ALONG THE COAST. HOWEVER...DO NOT THINK THEY WILL BE FREQUENT ENOUGH TO JUSTIFY A GALE WARNING. WITH THE INCREASING WINDS...EXPECT SHORT PERIOD FRESHLY GENERATED SWELL TO CREATE CHOPPY CONDITIONS ON THE WATERS. DECIDED TO ISSUE A SMALL CRAFT ADVISORY FOR SEAS WITH WAVE HEIGHTS EXPECTED TO BUILD INTO THE 8 TO 10 FT RANGE WITH PERIODS OF 8 OR 9 SEC. THE SURFACE TROUGH SHOULD PUSH ONSHORE BETWEEN 12Z AND 15Z...AFTER WHICH WINDS WILL SHIFT TO THE SW AND SUBSIDE SOMEWHAT. HOWEVER...LOW END SMALL CRAFT ADVISORY WINDS MAY CONTINUE THROUGH MUCH OF THE DAY...PARTICULARLY FURTHER SOUTH. THERE SHOULD BE A BIT OF A LULL IN THE WINDS AND SEAS LATER TOMORROW AND TOMORROW NIGHT. HOWEVER A STRONGER FRONT IS EXPECTED TO MOVE INTO THE WATERS SUN AND SUN NIGHT...WITH GALE FORCE WINDS A POSSIBILITY SUN NIGHT. ADDITIONAL MODERATE TO STRONG FRONTS ARE MODELED TO MOVE THROUGH THE PAC NW WATERS EVERY 24 TO 36 HRS THROUGH THE FIRST HALF OF NEXT WEEK. IT APPEARS THAT THERE WILL BE SEVERAL CHANCES FOR SOLID GALES...AND POSSIBLY EVEN SOME LOW END GALES ALTHOUGH CONFIDENCE IN THIS IS LOW AT THIS TIME. IN RESPONSE TO THIS SERIES OF FRONTS...THE ENP WAVE GUIDANCE IS PUSHING SEAS INTO THE UPPER TEENS TO NEAR 20 FT BEGINNING MON NIGHT AND REMAINING IN THIS GENERAL RANGE THROUGH MUCH OF THE WEEK. PYLE && .PQR WATCHES/WARNINGS/ADVISORIES... OR...FREEZING RAIN ADVISORY UNTIL 10 AM PST SATURDAY FOR UPPER HOOD RIVER VALLEY. WA...WINTER WEATHER ADVISORY UNTIL NOON PST SATURDAY FOR SOUTH WASHINGTON CASCADES. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST SATURDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON PST SATURDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST SATURDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion National Weather Service Spokane WA 710 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Evening update: the forecast is generally on track, with newest models continuing to bring the next batch of precipitation in from the west tonight into Saturday. The chances tonight will be largely near the Cascades, with the highest threat starting after about 09Z (1 AM). Some light precipitation will also be possible across the northern mountains of WA and ID tonight. Models then blossom the precipitation across the remainder of eastern WA and north ID between 4 AM and 1 PM Saturday, before things start to wind down from the west Saturday night. Some adjustments made to increase fog coverage from the previous forecast, though it is expected to be largely patchy in fashion and may still have opportunity to decrease from the southeast overnight. Main area I added some patchy fog was toward the Blues and L-C Valley, as well as out across the Basin into the the Waterville Plateau. The fog is down to a half mile or so in spots, such as near GEG and LWS, though it hasn`t been all that consistently that low in LWS. I kept the fog going through the night, but make it patchier in areas where it has been most dense (i.e. western Spokane county and along the highway 2 corridor. Later in the forecast, toward Saturday night into Sunday morning, models suggest some low level moisture and southwest flow will combine to bring a stratus and fog threat. It seems like a good pattern for it. So the forecast was update to add this for a good chunk of the basin/valley areas. Its coverage will be fine tuned over the next day or so. /J. Cote` && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 38 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 38 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 43 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 46 / 10 90 10 0 10 20 Colville 32 34 31 38 29 38 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 37 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 38 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$
Area Forecast Discussion National Weather Service Spokane WA 710 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Evening update: the forecast is generally on track, with newest models continuing to bring the next batch of precipitation in from the west tonight into Saturday. The chances tonight will be largely near the Cascades, with the highest threat starting after about 09Z (1 AM). Some light precipitation will also be possible across the northern mountains of WA and ID tonight. Models then blossom the precipitation across the remainder of eastern WA and north ID between 4 AM and 1 PM Saturday, before things start to wind down from the west Saturday night. Some adjustments made to increase fog coverage from the previous forecast, though it is expected to be largely patchy in fashion and may still have opportunity to decrease from the southeast overnight. Main area I added some patchy fog was toward the Blues and L-C Valley, as well as out across the Basin into the the Waterville Plateau. The fog is down to a half mile or so in spots, such as near GEG and LWS, though it hasn`t been all that consistently that low in LWS. I kept the fog going through the night, but make it patchier in areas where it has been most dense (i.e. western Spokane county and along the highway 2 corridor. Later in the forecast, toward Saturday night into Sunday morning, models suggest some low level moisture and southwest flow will combine to bring a stratus and fog threat. It seems like a good pattern for it. So the forecast was update to add this for a good chunk of the basin/valley areas. Its coverage will be fine tuned over the next day or so. /J. Cote` && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 38 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 38 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 43 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 46 / 10 90 10 0 10 20 Colville 32 34 31 38 29 38 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 37 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 38 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$
Area Forecast Discussion National Weather Service Spokane WA 405 PM PST FRI DEC 5 2014 .SYNOPSIS... A series of storm systems will bring a wintry mix of precipitation to the Pacific Northwest through a good portion of the weekend. Each day valley temperatures will warm a bit meaning a gradual transition from freezing rain and snow to just plain rain. A break in storm systems occurs Sunday but ends quickly with more winter storms passing through as early as Sunday night and continuing on through at least the early part of the next workweek. && .DISCUSSION... Tonight: Conditions will dry out across the eastern and southern third of the forecast area while the Cascades...Wenatchee Area...and areas of the northern mountain deal with a messy wintry mix. Precipitation for much of today has been uneventful to say the least with most midlevel circulations falling apart once they cross into Chelan County. Regional radar indicates a line of showers continuing to fill in from Kittitas County southward to the central Oregon Cascades which are tracking north toward the Hwy 97 corridor. It is uncertain whether these showers will survive the trip into Chelan/Douglas Counties but HRRR continues to hint at some showers during the 23-02z time-frame. Most locations remain below freezing with a few exceptions. With wetbulb effects and sunset approaching, it is unlikely any location will remain above freezing. The showers moving through the next few hours will not be a major player for freezing rain. Freezing rain advisories were extended to capture steady light to moderate precipitation moving in after midnight and continuing into Saturday morning. This is a much different setup compared the last 48 hours which have proved much drier than expected. This system will feature southeast flow in the lower levels, moderate isentropic ascent, and rich moisture. So as far as I am concerned, the precipitation will be certain...now the temperatures will be a bigger wild card. Temperatures are typically slow to warm with SE flow in the lower levels however as the air mass moistens...it has no where to go but warmer. When this transition occurs will be the challenge of the night. Needless to say, travel is likely to be slick near the Cascades and Wenatchee Area. Some light precip is possible in the Okanogan Valley and Northern Mountains but amounts should be low and concerns are lower. One other travel concern looks to be localized along Hwy 2 between Airway Heights and Davenport which is dense fog. There may be a few other areas out there, but this looks to be the worse case via a tour of CAMS and motorists should plan on visibilities near 1/4 mile at times. Temperatures remain near 32F for most locations north of I-90 so there is also the potential for black ice redeveloping tonight. Temperatures will not fall much from current readings (maybe 1-2 degrees) and may even rise or remain steady for much of the night so we are not expecting a hard freeze in any locations. /sb Saturday through Monday...High pressure will be over the Pacific Northwest through Sunday before getting pushed off to the east Sunday night. A couple of vigorous but fast moving short wave disturbances will move through the ridge...the first on Saturday...the second on Monday. These two waves will result in more wet weather across the region through the short term. Temperatures will be on the increase with warm air advection and should be above normal through Monday. *Precipitation: Yes more wet weather with chances of mixed precipitation. The wave moving through the region on Saturday will tap into fairly deep Pacific moisture and combine with moderate to strong isentropic up-glide and orographic lift for light to moderate precipitation. Precipitation will be on the increase across the western zones around 12z and push across the forecast area through the day. A cold front will follow quickly behind. The front should eject into Montana late Saturday afternoon. Low level southeast-south flow Saturday morning will eliminate any Cascade shadowing for the lowers east slopes and the deep basin. The flow will shift around to the southwest-west by late Saturday afternoon as the front moves through the area. Drying from the west should begin by late morning, with precipitation lingering across the Panhandle through the evening hours. Saturday night and Sunday the area will be in a dry period, although fog and low clouds will be probable. The next weak wave will run through the ridge on Monday. This wave does not have the deep moisture tap nor the lifting mechanism of the previous wave but will still result in some very light precipitation Monday afternoon. *Precipitation type: The valleys up against the Cascades have had difficulty mixing out the cold air damned up against the mountains. All indications are that precipitation may be as freezing rain overnight, but should turn over to snow before sunrise Saturday...especially for the Methow valley. Along the the Columbia river and some of the northern valleys freezing rain may also be a possibility for a few hours early Saturday morning, but with increasing southerly flow these valleys should switch over to rain. Precipitation amounts will range from around a tenth or more for the lower elevations and a quarter to a third of an inch for the mountains for the Saturday system. Snow accumulation of 3-4 inches will be possible for the mountains with possibly 1-2 inches for the Methow valley. For the Monday system precipitation should be as valley rain and mountain snow, with very light accumulations. Tobin Monday night through Friday: Confidence is high that the region will see a pattern shift through next week. Medium range models are in good agreement that the longwave ridge of high pressure will shift east into the Rookies and over the Northern Plains. This will place the region in a more mild and wet weather pattern. A pair of very moist low pressure systems will impact the region. There is still some uncertainty with the timing of these two systems. There is better agreement with the first system as models show the region firmly under the warm sector Monday night into Tuesday, and then the cold front sweeping through around Tuesday afternoon or night. Models diverge considerably more with the second weather system. The ECMWF is faster and shows a stronger warm frontal passage Tuesday night into Wednesday morning. The GFS is much slower with precip redeveloping Wednesday afternoon/evening. Snow levels will be increasing with each of these weather systems. A pocket of cold air looks to remain along the lee side of the northern Cascades into the Okanogan Highlands through at least Monday night. This will keep snow levels lower to between 2,000 and 3,000 feet. There is a chance for some wet snow in the upper reaches of the Methow Valley, but confidence is low. All other valley locations are expected to see rainfall. Moderate to heavy rainfall amounts will be possible with P-wats +2 standard deviations of normal and up to between 0.75-1.00 inches. Temperatures will warm to above normal through mid week. The upper level trough in the Gulf of Alaska looks to dig in across the region late next week. This will result in an end to the warming trend with temperatures dipping back closer to normal by Friday. /SVH && .AVIATION... 00Z TAFS: Widespread fog and low stratus will hang around much of the region with MVFR/IFR conditions expected through tonight. There is moderate confidence that flight conditions will improve at the KLWS, KGEG, KSFF and KCOE TAF sites overnight due to increased easterly flow that should bring in some drier air at lower levels. These same locations could see sky conditions scatter out, but confidence is low that this will occur due to how moist the boundary layer is early this evening. A mid level cold front will push across the region during the morning on Saturday. This will result in an increasing chance for light rain at all TAF sites with cigs degrading back into MVFR/IFR category. There is a slight chance for freezing rain at KEAT through tonight into Saturday morning, but there is some model discrepancy that temperatures will be able to cool back to below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 31 37 32 37 31 39 / 10 90 20 0 10 30 Coeur d`Alene 31 35 33 36 31 39 / 10 90 40 0 10 30 Pullman 38 39 33 38 35 44 / 10 100 20 0 10 30 Lewiston 37 39 35 45 37 47 / 10 90 10 0 10 20 Colville 32 34 31 38 29 39 / 30 70 30 0 10 30 Sandpoint 29 34 32 37 29 36 / 10 90 50 10 0 30 Kellogg 34 35 33 38 30 38 / 10 100 50 0 0 30 Moses Lake 34 36 30 40 32 39 / 50 90 0 0 10 30 Wenatchee 31 35 30 39 32 39 / 80 80 0 0 20 30 Omak 30 34 28 33 29 36 / 60 80 0 10 10 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Air Stagnation Advisory until Noon PST Tuesday for East Slopes Northern Cascades-Northeast Mountains-Okanogan Highlands- Okanogan Valley-Waterville Plateau-Wenatchee Area. Freezing Rain Advisory until Noon PST Saturday for East Slopes Northern Cascades-Wenatchee Area. && $$ Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 940 AM CST Sat Dec 6 2014 .UPDATE... ISSUED AT 939 AM CST SAT DEC 6 2014 Main concern for today is with cloud cover. Widespread stratus covers the forecast area this morning, with ceilings east of I-57 managing to reach just above 1000 feet while they remain 500 feet or less most areas west. This morning`s upper air sounding, plus forecast soundings off the latest NAM and RAP models, show a persistent inversion around 950 mb. There is some clearing that has occurred over the northwest corner of Illinois, but visible satellite loops showing only slow southern progress toward the Quad Cities area. We`re in the time of year where low sun angle makes it difficult to burn off the low clouds. Areas northwest of Peoria most likely to see any sun this afternoon although there will still be quite a few clouds around. The remainder of the CWA should remain mainly cloudy. Going forecast is in pretty good shape, and only required some minor tweaks to incorporate current trends. && .SHORT TERM...(Today) ISSUED AT 323 AM CST SAT DEC 6 2014 The 08z/2am surface analysis has a 1015mb low in NC Kentucky moving northeast along a stationary front. Rain showers on the NW flank of the low are steadily progressing eastward out of our E-SE counties. The back edge of precip should reach I-57 by 09z/3am and be completely out of our IL counties by 13z/7am. Despite dry air aloft flowing into Illinois on N-NW winds, a strong subsidence inversion is indicated in all the short term models. That will limit mixing of the dry air in to the low level moisture, and work to keep clouds across our forecast area over the next 12 hours if not well into tonight. The satellite images are showing a clearing line progressing south toward IL across MN/WI, however, that clearing should slow down with the intensification of the inversion today. High temps will not climb appreciably under the blanket of clouds, with readings topping out in the upper 30s toward Galesburg and into the mid 40s toward Lawrenceville. && .LONG TERM...(Tonight through Friday) ISSUED AT 323 AM CST SAT DEC 6 2014 High pressure continues to build into the region, although the inversion remains and will likely see a continuation of the clouds until the incredibly dry air aloft finally works its way down into the higher RH in the llvls. This same dry air is also the deciding factor in the next issue for the forecast with an approaching wave Sun night/Monday. Prev models had more disagreement and the NAM with a more southerly track for the wave was the outlier. With this run, both the GFS and ECMWF starting to look a lot more like the prev NAM. A small system developing into a larger upper trof late in the weekend...with the look of two smaller waves bringing pops back into the region. Although the GFS and the ECMWF are more consistent with the prev NAM, the NAM is far more scarce with the QPF. Keeping the forecast chances low for shower activity after midnight Sun night/Monday... not only for lack of continuity from run to run, but the considerable amount of dry air will take a while to overcome. Not convinced the best lift will coincide with the eventual saturation of the column. Beyond Monday and its cold front, temps cool briefly, then moderate back into the 40s for highs through the end of the week. 00z ECMWF completely pulls back on a small disturbance Wed night/Thursday, and should this trend continue, will likely pull the pops altogether out of the next couple runs. For now, slight pops in the forecast to cover a brief disturbance diving into the Great Lakes region on the retreating edge of the larger scale 500 mb trof exiting out to the northeast. This difference btwn the GFS and the European also delineates the break point in the extended between any agreement in the midst of a small pattern shift. Depth of the thickness ridge going into day 7 and 8 will definitely result in some blend issues going into next weekend. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 600 AM CST SAT DEC 6 2014 The cloud forecast will continue to be challenging over the next 24 hours, as a clearing line approaches central IL from the north. However, the HRRR and NAM keep low clouds entrenched until later this evening, while the GFS dissipates the low clouds this morning. The HRRR does show the brief small area of break in the low clouds that drifted across the area the last 6 hours, but it also indicates that break will fill in and the clearing line will barely graze our NW counties this afternoon, but not reach all the way to PIA. The NAM/SREF/RAP forecast soundings all show a strong subsidence inversion trapping the low level moisture across our terminal sites today. So confidence is moderate in keeping low clouds in place through the day. Ceiling heights will start out LIFR at BMI/DEC and IFR at PIA/CMI/SPI. All ceilings should at least climb to MVFR after 18z with heating of the day and lifting of the LCL. We went with some clearing eventually developing tonight with advancing high pressure and a deeper layer of dry air. Winds will remain north today at 10-14kt and shift to northeast tonight as they diminish below 10kt. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...Shimon LONG TERM...HJS AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
821 AM CST SAT DEC 6 2014 .SHORT TERM... 409 AM CST THROUGH SATURDAY NIGHT... FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...THE MAIN FORECAST CONCERNS WILL FOCUS ON SKY COVER AND THE IMPACT ON TEMPERATURE TRENDS. LATEST SURFACE ANALYSIS AND SATELLITE IMAGERY INDICATE AN EXTENSIVE STRATUS DECK ACROSS THE REGION TRAPPED BENEATH A STRONG INVERSION BASED AT AROUND 900MB. LATEST MODEL SOUNDINGS INDICATE THAT THE INVERSION WILL HOLD FAST THROUGH THE REMAINDER OF THE NIGHT AND MUCH OF THE DAY SATURDAY. ALSO...AS THE CENTER OF HIGH PRESSURE MOVES ACROSS THE UPPER GREAT LAKES AND LOW PRESSURE CONTINUES TO MOVE THROUGH THE OHIO VALLEY...WINDS WILL REMAIN NELY OFF OF LAKE MICHIGAN...KEEPING MUCH OF NERN IL AND NWRN IN UNDER CLOUD COVER A BIT LONGER THAN PREVIOUSLY ANTICIPATED. AS THE CENTER OF THE HIGH SHIFTS TO THE EAST LATE THIS AFTERNOON AND THIS EVENING...SFC FLOW WILL VEER MORE ELY-SELY...ALLOWING THE STRATUS DECK TO FINALLY SCATTER OUT. NWRN PORTIONS OF THE CWA...GENERALLY WEST OF THE FOX VALLEY COULD SCATTER OUT A BIT QUICKER THAN NERN IL/NWRN IN AND LOCATION UNDER A FETCH OFF OF LAKE MICHIGAN. THIS MAKES THE TEMPERATURE FORECAST FOR SATURDAY A BIT TRICKY AND WILL ULTIMATELY DEPEND ON HOW QUICKLY CLOUD COVER CAN BREAK UP. HOWEVER...THE REGION WILL STILL BE UNDER A COLD ADVECTIVE PATTERN AS THE CENTER OF THE HIGH BUILDS ACROSS NRN MN AND LAKE SUPERIOR TODAY...SO THE DIURNAL TEMPERATURE TREND SHOULD BE A LITTLE SLOWER THAN...BUT AS THE CENTER OF THE HIGH SHIFT EAST OF LAKE SUPERIOR LATE THIS AFTERNOON...THERE IS THE POTENTIAL FOR A LITTLE WARM ADVECTION...AND WITH CLEARING SKIES...TEMPERATURES COULD SPIKE A FEW DEGREES LATE THIS AFTERNOON...BEFORE THE SUN ANGLE GETS TOO LOW. FOR THE REMAINDER OF SATURDAY NIGHT...EXPECT QUIET CONDITIONS AS SFC RIDGING EXTENDS SOUTHWEST ACROSS THE AREA AND THROUGH THE MIDDLE MISSISSIPPI VALLEY...WITH WINDS GRADUALLY VEERING TO SELY BY SUNDAY MORNING. WITH DECREASING CLOUD COVER...DECREASING LOW LEVEL MOISTURE...THE LOWER LEVELS SHOULD BE ABLE TO DECOUPLE OVERNIGHT WITH WINDS DROPPING OFF AND RADIATIVE COOLING ALLOWING FOR TEMPERATURES TO DROP INTO THE LOWER 20S FOR MOST AREAS...WITH THE EXCEPTION OF THE URBAN HEAT ISLAND OF THE CHICAGO METRO AREA WHICH SHOULD REMAIN IN THE UPPER 20S TO AROUND 30F. KREIN && .LONG TERM... 409 AM CST SUNDAY THROUGH NEXT FRIDAY... SUNDAY IS SHAPING UP TO BE A RELATIVELY PLEASANT DAY WITH SELY WINDS PERSISTING THROUGH THE DAY AS THE HIGH MOVES INTO SERN CANADA AND A LOW PRESSURE SYSTEM MOVES OUT OF THE SRN CANADIAN ROCKIES AND ACROSS THE NRN PLAINS. THE EVOLUTION OF THIS SYSTEM HAS BEEN RELATIVELY CONSISTENT OVER RECENT MODEL RUNS...IN TRACKING ACROSS THE NORTHERN PLAINS AND DRAGGING A WEAK COLD FRONT AS IT TRACKS EWD. WINDS AHEAD OF THE SYSTEM WILL VEER TO MORE SOUTHERLY ALLOWING SOME WARMER AIR TO FILTER INTO THE REGION...BRINGING HIGHS IN THE UPPER 30S ACROSS THE AREA. THE WEATHER PICTURE BECOMES A LITTLE MORE COMPLICATED AS THE NEXT SYSTEM APPROACHES THE REGION. SINCE HIGH PRESSURE RIDGING IS STILL EXPECTED TO EXTEND FROM NEW ENGLAND THROUGH THE LOWER MISSISSIPPI VALLEY...THE GULF OF MEXICO WILL BE CUT OFF FROM THE APPROACHING SYSTEM AND THE ONLY AVAILABLE MOISTURE FOR IT TO WORK WITH WILL BE THE MEAGER AMOUNTS IN PLACE...PWATS AROUND A QUARTER OF AN INCH AND WHAT MOISTURE IT CAN BRING AS A PACIFIC SOURCED MID LEVEL SHORTWAVE. THROUGH THE EVENING ON SUNDAY...SFC TEMPERATURES ARE EXPECTED TO DROP OFF INTO THE UPPER 20S TO THE LOWER 30S. MODEL SOUNDING FOR SUNDAY NIGHT INTO MONDAY MORNING INDICATE WARMING ABOVE THE BOUNDARY LAYER WITH TEMPS RISING TO 1-2C ABOVE A SUB-FREEZING SFC LAYER. THE PCPN TYPE FORECAST FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE COMPLICATED BY THE DEPTH AND DEGREE OF THE WARM LAYER AND HOW FAR NORTH THE WARM LAYER CAN REACH. THE LATEST GUIDANCE SUGGESTS THAT PCPN SHOULD START OUT AS A LITTLE LIGHT SNOW OVER THE ROCKFORD AREA EARLY SUNDAY EVENING BEFORE THE WARM INTRUSION REACHES INTO NCNTRL IL...WITH A TRANSITION OVER TO FREEZING RAIN AND...PERHAPS...A LITTLE SLEET MIXING IN...WHICH WOULD BE DEPENDENT ON THE DEPTH OF THE SURFACE-BASED FREEZING LAYER. AS THE SYSTEM SLOWLY CROSSES THE AREA...MANY LOCATIONS COULD SEE A PERIOD OF LIGHT FREEZING RAIN LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING...BEFORE CHANGING OVER TO ALL RAIN BY MIDDAY MONDAY. WITH AVAILABLE DEEP LAYER MOISTURE STILL LIMITED...WITH PWATS ONLY OF A HALF INCH OR SO...PCPN AMOUNTS SHOULD BE LIGHT...BUT EVEN A LIGHT GLAZING OF FREEZING RAIN IN TIME FOR THE MONDAY MORNING RUSH HOURS COULD CREATE TRAVEL DIFFICULTIES. HOWEVER...HIGH PRESSURE IS EXPECTED TO QUICKLY BUILD ACROSS THE REGION FOLLOWING THE FRONTAL PASSAGE...AND ANY PCPN SHOULD COME TO AN END BY LATE MONDAY AFTERNOON OVER THE WRN PORTIONS OF THE CWA AND IN THE EARLY EVENING FOR THE FAR SOUTHEAST. TEMPERATURES SHOULD BE HIGH ENOUGH DURG THE LATE AFTERNOON HOURS THAT THE CHANCES FOR ANY FREEZING PCPN FOR THE EVENING RUSH HOURS ARE LOW. AS THE NEXT AREA OF HIGH PRESSURE BUILDS ACROSS THE REGION...A SHORT PERIOD OF COOL...DRY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY...WITH HIGHS IN THE LOWER TO MIDDLE 30S AND OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. THE SYSTEM PASSING THROUGH THE AREA MONDAY NIGHT IS EXPECTED TO DEVELOP INTO A DEEP UPPER LOW OVER THE MID ATLANTIC REGION BY WEDNESDAY AND THEN SLOWLY MOVE UP THE EAST COAST. BY WEDNESDAY NIGHT...THE DEEP UPPER LOW WILL MOVE OVER NEW ENGLAND AS UPPER RIDING BUILDS FROM THE SRN ROCKIES THROUGH THE UPPER MISSISSIPPI VALLEY. A WEAK SHORTWAVE IN THE NLY FLOW ALOFT BETWEEN THESE TO LARGE SCALE SYSTEMS COULD BRING A BIT OF LIGHT SNOW FOR WEDNESDAY NIGHT INTO THURSDAY...BUT ANY ASSOCIATED SNOWFALL SHOULD BE LIGHT. TOWARDS THE END OF THE WEEK..THE UPPER RIDGING IS EXPECTED TO BUILD ACROSS THE UPPER MIDWEST...BRINGING A WARMING TREND FOR LATE NEXT WEEK...WITH TEMPS POSSIBLY REACHING THE LOWER TO MIDDLE 40S BY NEXT FRIDAY. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * CIGS AROUND 1500 FT LIFTING THROUGH MIDDAY AND SCATTERING SOME TIME LATE THIS AFTERNOON. * N-NNE WINDS 12-15 KT GUSTING TO 20-25 KT AT TIMES THROUGH THE AFTERNOON. KMD //DISCUSSION...UPDATED 12Z... LOW PRESSURE CONTINUES TO MOVE NORTHEAST UP THE OHIO RIVER VALLEY WHILE HIGH PRESSURE MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. STEADIER N TO NE WINDS HAVE SET UP IN THE 10-14 KT RANGE WITH SPORADIC GUSTS ALSO APPEARING AT TIMES. GUSTS WILL LIKELY BECOME MORE FREQUENT THIS AFTERNOON ESPECIALLY WHERE BREAKS CAN DEVELOP IN THE CLOUD COVER. WINDS WILL GRADUALLY DIMINISH AND TURN NORTHEAST THIS EVENING BEFORE SHIFTING SOUTHEAST TOWARD DAYBREAK MONDAY. CIGS WILL BE A CHALLENGE THROUGH THE MORNING. OBS SHOW BASE HEIGHTS RANGING FROM 600-1100 FT ACROSS THE TERMINALS AND POINTS UPSTREAM. A SLIGHT WIND COMPONENT OFF THE LAKE SEEMS TO BE KEEPING BASES A LITTLE HIGHER WITHIN SEVERAL MILES INLAND OF THE SHORE THANKS TO WARMER AIR OVER THE WATER. SATELLITE IMAGERY SHOWS A WELL DEFINED BACK EDGE TO THE STRATUS ACROSS SOUTHERN WISCONSIN WHICH IS MOVING SOUTHEAST. STRATUS IS ALSO EXTENSIVE ACROSS LAKE MICHIGAN. THE BACK EDGE OF THIS STRATUS WILL LIKELY WORK ACROSS MOST OF IF NOT ALL OF THE AREA THROUGH AROUND 16Z. HOWEVER...THERE IS NOT SIGNIFICANT AMOUNTS OF DRY AIR WORKING INTO THE REGION SO SCT-BKN STRATO CU MAY DEVELOP TOWARD MIDDAY....PROVIDED THE CURRENT BAND DOES EXIT AND DOES NOT SLOW ITS SOUTHWARD PROGRESS. IN OTHER WORDS THERE MAY BE A BREAK IN THE LOW CLOUDS BEFORE DIURNAL CU DEVELOPS. ALSO...FLOW IN THE CLOUD LAYER WILL BE AIMED FROM THE NORTHEAST RIGHT ACROSS THE LAKE SO LAKE PROCESSES MAY BE SUFFICIENT TO KEEP STRATUS GOING AT LEAST WITHIN SEVERAL MILES OF SHORE WELL INTO THE AFTERNOON. WILL GO AHEAD AND KEEP A LONGER PERIOD OF STRATUS IN THE FORECAST FOR NOW WHICH COULD BE PESSIMISTIC. OTHERWISE SKIES WILL CLEAR THIS EVENING IF THEY DO NOT DO SO EARLIER. MORNING VSBY BETWEEN 2-5 SM WILL IMPROVE AS WE GRADUALLY BEGIN TO WARM UP AFTER DAYBREAK. MDB //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN CLOUD BASES LIFTING THROUGH MIDDAY...BUT LOW CONFIDENCE IN TIMING OF SCATTERING. * HIGH CONFIDENCE IN WIND TRENDS. KMD //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...MAINLY VFR. SLGT CHANCE OF LIGHT SNOW/SLEET AND MVFR SUNDAY. E WINDS BECOMING SE. MONDAY...CHANCE RAIN/SLEET/SNOW. MVFR/BRIEF IFR POSSIBLE. S WINDS BECOMING W. TUESDAY...VFR. NW WINDS BECOMING N. WEDNESDAY...VFR. NE WINDS BECOMING ESE. THURSDAY...SLGT CHANCE LIGHT SNOW. VFR. S WINDS. FRIDAY...VFR. SSE WINDS. MDB && .MARINE... 256 AM CST LOW PRESSURE CONTINUES TO MOVE NORTHEAST UP THE OHIO RIVER VALLEY EARLY THIS MORNING WITH STRONG HIGH PRESSURE MOVING EASTWARD ACROSS THE EASTERN DAKOTAS. WINDS ARE STARTING TO INCREASE AS THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS TIGHTENS UP THROUGH THE MORNING. AS A RESULT...EXPECT NORTH TO NORTHEAST WINDS TO RANGE FROM 20 TO 25 KT WITH GUSTS TO 30 KT ACROSS THE CENTRAL AND SOUTHERN PARTS OF THE LAKE THIS MORNING/AFTERNOON WITH NORTHERN AREAS DIMINISHING THROUGH THE AFTERNOON AS THE INFLUENCE OF THE HIGH ARRIVES. SPEEDS WILL DIMINISH ACROSS THE LAKE THIS EVENING AND TONIGHT AS THE DIRECTION TURNS EAST THEN SOUTHEAST AS THE HIGH SHIFTS TO THE EAST. WILL CONTINUE WITH THE SMALL CRAFT ADVISORY INTO EARLY TONIGHT AS THE LONG FETCH OF WIND WILL KEEP WAVES ELEVATED AFTER WINDS DIMINISH THIS EVENING. LOW PRESSURE WILL DEVELOP IN THE LEE OF THE NORTHERN ROCKIES SUNDAY AND MOVE EASTWARD ALONG THE U.S./CANADIAN BORDER...CROSSING LAKE SUPERIOR MONDAY EVENING. THE LOW WILL DRAG A COLD FRONT ACROSS THE LAKE MONDAY EVENING. SOUTHERLY WINDS WILL INCREASE AHEAD OF THE LOW SUNDAY AND SUNDAY NIGHT THEN SHIFT TO THE NORTHWEST BEHIND THE FRONT MONDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD IN BEHIND THE LOW INTO TUESDAY WITH A FAIRLY STRONG PUSH OF COLDER AIR AND A TIGHT PRESSURE GRADIENT SUPPORTING GUSTY NORTH TO NORTHWEST WINDS. WINDS WILL DIMINISH WEDNESDAY AS THE HIGH MOVES OVERHEAD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 610 AM CST Sat Dec 6 2014 .SHORT TERM...(Today) ISSUED AT 323 AM CST SAT DEC 6 2014 The 08z/2am surface analysis has a 1015mb low in NC Kentucky moving northeast along a stationary front. Rain showers on the NW flank of the low are steadily progressing eastward out of our E-SE counties. The back edge of precip should reach I-57 by 09z/3am and be completely out of our IL counties by 13z/7am. Despite dry air aloft flowing into Illinois on N-NW winds, a strong subsidence inversion is indicated in all the short term models. That will limit mixing of the dry air in to the low level moisture, and work to keep clouds across our forecast area over the next 12 hours if not well into tonight. The satellite images are showing a clearing line progressing south toward IL across MN/WI, however, that clearing should slow down with the intensification of the inversion today. High temps will not climb appreciably under the blanket of clouds, with readings topping out in the upper 30s toward Galesburg and into the mid 40s toward Lawrenceville. && .LONG TERM...(Tonight through Friday) ISSUED AT 323 AM CST SAT DEC 6 2014 High pressure continues to build into the region, although the inversion remains and will likely see a continuation of the clouds until the incredibly dry air aloft finally works its way down into the higher RH in the llvls. This same dry air is also the deciding factor in the next issue for the forecast with an approaching wave Sun night/Monday. Prev models had more disagreement and the NAM with a more southerly track for the wave was the outlier. With this run, both the GFS and ECMWF starting to look a lot more like the prev NAM. A small system developing into a larger upper trof late in the weekend...with the look of two smaller waves bringing pops back into the region. Although the GFS and the ECMWF are more consistent with the prev NAM, the NAM is far more scarce with the QPF. Keeping the forecast chances low for shower activity after midnight Sun night/Monday... not only for lack of continuity from run to run, but the considerable amount of dry air will take a while to overcome. Not convinced the best lift will coincide with the eventual saturation of the column. Beyond Monday and its cold front, temps cool briefly, then moderate back into the 40s for highs through the end of the week. 00z ECMWF completely pulls back on a small disturbance Wed night/Thursday, and should this trend continue, will likely pull the pops altogether out of the next couple runs. For now, slight pops in the forecast to cover a brief disturbance diving into the Great Lakes region on the retreating edge of the larger scale 500 mb trof exiting out to the northeast. This difference btwn the GFS and the European also delineates the break point in the extended between any agreement in the midst of a small pattern shift. Depth of the thickness ridge going into day 7 and 8 will definitely result in some blend issues going into next weekend. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 600 AM CST SAT DEC 6 2014 The cloud forecast will continue to be challenging over the next 24 hours, as a clearing line approaches central IL from the north. However, the HRRR and NAM keep low clouds entrenched until later this evening, while the GFS dissipates the low clouds this morning. The HRRR does show the brief small area of break in the low clouds that drifted across the area the last 6 hours, but it also indicates that break will fill in and the clearing line will barely graze our NW counties this afternoon, but not reach all the way to PIA. The NAM/SREF/RAP forecast soundings all show a strong subsidence inversion trapping the low level moisture across our terminal sites today. So confidence is moderate in keeping low clouds in place through the day. Ceiling heights will start out LIFR at BMI/DEC and IFR at PIA/CMI/SPI. All ceilings should at least climb to MVFR after 18z with heating of the day and lifting of the LCL. We went with some clearing eventually developing tonight with advancing high pressure and a deeper layer of dry air. Winds will remain north today at 10-14kt and shift to northeast tonight as they diminish below 10kt. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Shimon LONG TERM...HJS AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
948 AM EST SAT DEC 6 2014 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 356 AM EST SAT DEC 6 2014 RAINFALL WILL COME TO AN END TODAY AS LOW PRESSURE GRADUALLY EXITS THE REGION. CLOUD COVER WILL PERSIST HOWEVER AS AMPLE LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG INVERSION. DRY WEATHER WILL CONTINUE THROUGH SUNDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. A SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE GREAT LAKES MONDAY AND MONDAY NIGHT MAY PRODUCE SOME LIGHT RAIN ACROSS PORTIONS OF THE AREA. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD. && .NEAR TERM /REST OF TODAY/... ISSUED AT 948 AM EST SAT DEC 6 2014 RAINFALL HAS EXITED THE FORECAST AREA FOR THE MOST PART...SO WILL TAKE OUT POPS FOR THE REST OF THE DAY. SHORT TERM MODELS SUGGEST LITTLE CHANCE OF ANY SIGNIFICANT CLEARING TODAY. THICK CLOUD COVER COMBINED WITH LOW LEVEL COLD ADVECTION SUGGESTS ONLY SUBTLE TEMPERATURE RISES FOR THE REST OF THE DAY. PREVIOUS DISCUSSION FOLLOWS. BETWEEN HRRR AND EXTRAPOLATION FROM LATEST RADAR TRENDS...EXPECT PRECIPITATION TO COME TO AN END ACROSS CENTRAL INDIANA BY NOON...AND WILL RAPIDLY TAPER OFF POPS AS SUCH FROM WEST TO EAST. STRONG LOW LEVEL INVERSION WILL REMAIN ACROSS THE AREA IN THE WAKE OF THE LOW PRESSURE SYSTEM WITH MOISTURE TRAPPED...THUS IT APPEARS THAT MODEL GUIDANCE IS CLEARING SKIES OUT FAR TOO QUICKLY. HAVE DELAYED ANY CLEARING WHATSOEVER INTO THE AFTERNOON AND THERE IS SOME CHANCE EVEN THIS IS TOO EARLY. LEANED SLIGHTLY COOLER THAN GUIDANCE AS A RESULT OF THIS AMPLE CLOUD COVER AND ONGOING COLD ADVECTION THROUGH THE DAY. MAY SEE HIGH TEMPERATURES EARLY IN THE DAY IN SOME LOCATIONS WITH TEMPERATURES STEADY OR SLOWLY FALLING LATE IN THE DAY. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 356 AM EST SAT DEC 6 2014 LATEST MODELS ARE COMING IN WETTER WITH THE SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. WILL HAVE TO CARRY SOME POPS MONDAY AND INTO MONDAY EVENING...BUT WITH SOUNDINGS ONLY BRIEFLY SATURATING MONDAY...AND DRYING QUICKLY FROM ALOFT LATE MONDAY NIGHT...WILL GO NO FURTHER THAN LOW CHANCE POPS AND WILL END PRECIP BY 06Z MONDAY NIGHT. MONDAY EVENING...PRECIP MAY COME MORE IN THE FORM OF DRIZZLE AS DRY AIR WORKS INTO THE AREA ALOFT BUT WITH WEAKLY POSITIVE OMEGA NOTED IN MOIST LOW LEVELS. EXPECT THAT PRECIP WILL HAVE ENDED BY THE TIME ANY FREEZING OR NEAR FREEZING TEMPERATURES MOVE INTO THE AREA. MODEL CONSENSUS APPEARED TO TRACK RELATIVELY WELL WITH LOW LEVEL THICKNESS PROGS...ASIDE FROM A FEW MINOR TWEAKS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 061500Z KIND TAF UPDATE/... ISSUED AT 921 AM EST SAT DEC 6 2014 A LARGE AREA OF MAINLY MVFR VISIBILITY RESTRICTIONS IN LIGHT FOG CONTINUES ACROSS THE AREA...SO IT WILL PROBABLY BE SEVERAL MORE HOURS BEFORE VISIBILITIES IMPROVE. WILL LOWER THE VISIBILITY FORECAST INTO THE MVFR CATEGORY INTO THE EARLY AFTERNOON ON THE UPDATE. PREVIOUS DISCUSSION FOLLOWS. IFR CONDITIONS WILL IMPROVE TO MVFR LATE THIS MORNING BEFORE IMPROVING TO VFR OVERNIGHT. SATELLITE CONTINUES TO SHOW EXTENSIVE CLOUDINESS ACROSS INDIANA...ILLINOIS..MISSOURI AND IOWA. SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER EASTERN KENTUCKY...PULLING NORTHEAST. RADAR SHOWS THE BACK EDGE OF PRECIP ALONG A LAF/HUF LINE...PUSHING EAST. SHOWERS ARE EXPECTED TO END BY 14Z AT ALL THE TAF SITES...HOWEVER EXTENSIVE CLOUDS WILL REMAIN AS TIME HEIGHTS SHOW LINGERING LOWER LEVEL MOISTURE THROUGH THE DAY AND THE PREVIOUSLY MENTIONED UPSTREAM OBS WITH PLENTIFUL CLOUDINESS. THUS WILL CONTINUE MVFR CIGS THROUGH MUCH OF THE DAY AS SURFACE HIGH PRESSURE SLOWLY WORKS IN. RIDGING ALOFT FINALLY BEGINS TO WORK IN OVERNIGHT...AND WILL TREND TOWARD VFR AT THAT TIME AS ANTICYCLONIC FLOW BECOMES PREDOMINATE. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NIELD NEAR TERM...NIELD/JAS SHORT TERM...NIELD LONG TERM...PUMA AVIATION...JP/JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
921 AM EST SAT DEC 6 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 356 AM EST SAT DEC 6 2014 RAINFALL WILL COME TO AN END TODAY AS LOW PRESSURE GRADUALLY EXITS THE REGION. CLOUD COVER WILL PERSIST HOWEVER AS AMPLE LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG INVERSION. DRY WEATHER WILL CONTINUE THROUGH SUNDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. A SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE GREAT LAKES MONDAY AND MONDAY NIGHT MAY PRODUCE SOME LIGHT RAIN ACROSS PORTIONS OF THE AREA. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD. && .NEAR TERM /TODAY/... ISSUED AT 356 AM EST SAT DEC 6 2014 BETWEEN HRRR AND EXTRAPOLATION FROM LATEST RADAR TRENDS...EXPECT PRECIPITATION TO COME TO AN END ACROSS CENTRAL INDIANA BY NOON...AND WILL RAPIDLY TAPER OFF POPS AS SUCH FROM WEST TO EAST. STRONG LOW LEVEL INVERSION WILL REMAIN ACROSS THE AREA IN THE WAKE OF THE LOW PRESSURE SYSTEM WITH MOISTURE TRAPPED...THUS IT APPEARS THAT MODEL GUIDANCE IS CLEARING SKIES OUT FAR TOO QUICKLY. HAVE DELAYED ANY CLEARING WHATSOEVER INTO THE AFTERNOON AND THERE IS SOME CHANCE EVEN THIS IS TOO EARLY. LEANED SLIGHTLY COOLER THAN GUIDANCE AS A RESULT OF THIS AMPLE CLOUD COVER AND ONGOING COLD ADVECTION THROUGH THE DAY. MAY SEE HIGH TEMPERATURES EARLY IN THE DAY IN SOME LOCATIONS WITH TEMPERATURES STEADY OR SLOWLY FALLING LATE IN THE DAY. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 356 AM EST SAT DEC 6 2014 LATEST MODELS ARE COMING IN WETTER WITH THE SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. WILL HAVE TO CARRY SOME POPS MONDAY AND INTO MONDAY EVENING...BUT WITH SOUNDINGS ONLY BRIEFLY SATURATING MONDAY...AND DRYING QUICKLY FROM ALOFT LATE MONDAY NIGHT...WILL GO NO FURTHER THAN LOW CHANCE POPS AND WILL END PRECIP BY 06Z MONDAY NIGHT. MONDAY EVENING...PRECIP MAY COME MORE IN THE FORM OF DRIZZLE AS DRY AIR WORKS INTO THE AREA ALOFT BUT WITH WEAKLY POSITIVE OMEGA NOTED IN MOIST LOW LEVELS. EXPECT THAT PRECIP WILL HAVE ENDED BY THE TIME ANY FREEZING OR NEAR FREEZING TEMPERATURES MOVE INTO THE AREA. MODEL CONSENSUS APPEARED TO TRACK RELATIVELY WELL WITH LOW LEVEL THICKNESS PROGS...ASIDE FROM A FEW MINOR TWEAKS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 061500Z KIND TAF UPDATE/... ISSUED AT 921 AM EST SAT DEC 6 2014 A LARGE AREA OF MAINLY MVFR VISIBILITY RESTRICTIONS IN LIGHT FOG CONTINUES ACROSS THE AREA...SO IT WILL PROBABLY BE SEVERAL MORE HOURS BEFORE VISIBILITIES IMPROVE. WILL LOWER THE VISIBILITY FORECAST INTO THE MVFR CATEGORY INTO THE EARLY AFTERNOON ON THE UPDATE. PREVIOUS DISCUSSION FOLLOWS. IFR CONDITIONS WILL IMPROVE TO MVFR LATE THIS MORNING BEFORE IMPROVING TO VFR OVERNIGHT. SATELLITE CONTINUES TO SHOW EXTENSIVE CLOUDINESS ACROSS INDIANA...ILLINOIS..MISSOURI AND IOWA. SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER EASTERN KENTUCKY...PULLING NORTHEAST. RADAR SHOWS THE BACK EDGE OF PRECIP ALONG A LAF/HUF LINE...PUSHING EAST. SHOWERS ARE EXPECTED TO END BY 14Z AT ALL THE TAF SITES...HOWEVER EXTENSIVE CLOUDS WILL REMAIN AS TIME HEIGHTS SHOW LINGERING LOWER LEVEL MOISTURE THROUGH THE DAY AND THE PREVIOUSLY MENTIONED UPSTREAM OBS WITH PLENTIFUL CLOUDINESS. THUS WILL CONTINUE MVFR CIGS THROUGH MUCH OF THE DAY AS SURFACE HIGH PRESSURE SLOWLY WORKS IN. RIDGING ALOFT FINALLY BEGINS TO WORK IN OVERNIGHT...AND WILL TREND TOWARD VFR AT THAT TIME AS ANTICYCLONIC FLOW BECOMES PREDOMINATE. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NIELD NEAR TERM...NIELD SHORT TERM...NIELD LONG TERM...PUMA AVIATION...JP/JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
553 AM EST SAT DEC 6 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 356 AM EST SAT DEC 6 2014 RAINFALL WILL COME TO AN END TODAY AS LOW PRESSURE GRADUALLY EXITS THE REGION. CLOUD COVER WILL PERSIST HOWEVER AS AMPLE LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG INVERSION. DRY WEATHER WILL CONTINUE THROUGH SUNDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. A SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE GREAT LAKES MONDAY AND MONDAY NIGHT MAY PRODUCE SOME LIGHT RAIN ACROSS PORTIONS OF THE AREA. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD. && .NEAR TERM /TODAY/... ISSUED AT 356 AM EST SAT DEC 6 2014 BETWEEN HRRR AND EXTRAPOLATION FROM LATEST RADAR TRENDS...EXPECT PRECIPITATION TO COME TO AN END ACROSS CENTRAL INDIANA BY NOON...AND WILL RAPIDLY TAPER OFF POPS AS SUCH FROM WEST TO EAST. STRONG LOW LEVEL INVERSION WILL REMAIN ACROSS THE AREA IN THE WAKE OF THE LOW PRESSURE SYSTEM WITH MOISTURE TRAPPED...THUS IT APPEARS THAT MODEL GUIDANCE IS CLEARING SKIES OUT FAR TOO QUICKLY. HAVE DELAYED ANY CLEARING WHATSOEVER INTO THE AFTERNOON AND THERE IS SOME CHANCE EVEN THIS IS TOO EARLY. LEANED SLIGHTLY COOLER THAN GUIDANCE AS A RESULT OF THIS AMPLE CLOUD COVER AND ONGOING COLD ADVECTION THROUGH THE DAY. MAY SEE HIGH TEMPERATURES EARLY IN THE DAY IN SOME LOCATIONS WITH TEMPERATURES STEADY OR SLOWLY FALLING LATE IN THE DAY. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 356 AM EST SAT DEC 6 2014 LATEST MODELS ARE COMING IN WETTER WITH THE SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. WILL HAVE TO CARRY SOME POPS MONDAY AND INTO MONDAY EVENING...BUT WITH SOUNDINGS ONLY BRIEFLY SATURATING MONDAY...AND DRYING QUICKLY FROM ALOFT LATE MONDAY NIGHT...WILL GO NO FURTHER THAN LOW CHANCE POPS AND WILL END PRECIP BY 06Z MONDAY NIGHT. MONDAY EVENING...PRECIP MAY COME MORE IN THE FORM OF DRIZZLE AS DRY AIR WORKS INTO THE AREA ALOFT BUT WITH WEAKLY POSITIVE OMEGA NOTED IN MOIST LOW LEVELS. EXPECT THAT PRECIP WILL HAVE ENDED BY THE TIME ANY FREEZING OR NEAR FREEZING TEMPERATURES MOVE INTO THE AREA. MODEL CONSENSUS APPEARED TO TRACK RELATIVELY WELL WITH LOW LEVEL THICKNESS PROGS...ASIDE FROM A FEW MINOR TWEAKS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 061200Z TAFS/... ISSUED AT 529 AM EST SAT DEC 6 2014 IFR CONDITIONS WILL IMPROVE TO MVFR LATE THIS MORNING BEFORE IMPROVING TO VFR OVERNIGHT. SATELLITE CONTINUES TO SHOW EXTENSIVE CLOUDINESS ACROSS INDIANA...ILLINOIS..MISSOURI AND IOWA. SURFACE ANALYSIS EARLY THIS MORNING SHOWS LOW PRESSURE OVER EASTERN KENTUCKY...PULLING NORTHEAST. RADAR SHOWS THE BACK EDGE OF PRECIP ALONG A LAF/HUF LINE...PUSHING EAST. SHOWERS ARE EXPECTED TO END BY 14Z AT ALL THE TAF SITES...HOWEVER EXTENSIVE CLOUDS WILL REMAIN AS TIME HEIGHTS SHOW LINGERING LOWER LEVEL MOISTURE THROUGH THE DAY AND THE PREVIOUSLY MENTIONED UPSTREAM OBS WITH PLENTIFUL CLOUDINESS. THUS WILL CONTINUE MVFR CIGS THROUGH MUCH OF THE DAY AS SURFACE HIGH PRESSURE SLOWLY WORKS IN. RIDGING ALOFT FINALLY BEGINS TO WORK IN OVERNIGHT...AND WILL TREND TOWARD VFR AT THAT TIME AS ANTICYCLONIC FLOW BECOMES PREDOMINATE. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NIELD NEAR TERM...NIELD SHORT TERM...NIELD LONG TERM...PUMA AVIATION...JP VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
917 AM CST SAT DEC 6 2014 ...UPDATE TO SYNOPSIS... .SYNOPSIS... ISSUED AT 915 AM CST SAT DEC 6 2014 WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE MOVING EASTWARD ACROSS THE WESTERN HIGH PLAINS. MEANWHILE, AN UPPER LEVEL SHORTWAVE TROUGH IS PUSHING ASHORE INTO SOUTHERN CALIFORNIA. NEAR THE SURFACE, A BROAD AREA OF HIGH PRESSURE EXTENDS FROM THE UPPER MIDWEST SOUTHWEST INTO THE CENTRAL PLAINS OF KANSAS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 210 AM CST SAT DEC 6 2014 A SOUTHEASTERLY FLOW WILL DEVELOP BY LATE AFTERNOON AS A TROUGH OF LOW PRESSURE BEGINS DEEPENS ALONG THE LEE OF THE ROCKIES AND A SURFACE HIGH MOVES EAST TOWARDS THE MID MISSISSIPPI VALLEY. NAM, RAP, NMM, AND ARW WERE ALL IN GOOD AGREEMENT WITH MORE HUMID AIR IN LOWER LEVELS SPREADING BACK INTO SOUTHWEST KANSAS BY EARLY TONIGHT AS THIS SOUTHEASTERLY FLOW DEVELOPS. BASED ON THE AGREEMENT BETWEEN THE NEAR TERM MODELS AND EVEN RUN TO RUN CONSISTENCY WILL EXPAND THE FOG POTENTIAL ACROSS ALL OF WESTERN KANSAS TONIGHT BASED ON INCREASING LOW LEVEL MOISTURE AND UPSLOPE FLOW. DENSE FOG ALSO MAY BE POSSIBLE AFTER MIDNIGHT EAST OF HIGHWAY 283 GIVEN THE LIGHTER LOW LEVEL WINDS. DEPTH OF THIS LOW LEVEL MOISTURE WILL STAY BELOW 3000FT AGL SO AM NOT ANTICIPATING DRIZZLE DEVELOPMENT. HOWEVER WITH WARM AIR ADVECTION, MOISTURE, AND WEAK ISENTROPIC LIFT DEVELOPING AHEAD OF AN UPPER LEVEL TROUGH ACROSS SOUTH CENTRAL AND NORTH CENTRAL KANSAS WILL GO AHEAD AND INSERT A CHANCE FOR SPRINKLES OR EVEN AN ISOLATED RAIN SHOWER. AS FOR LOWS TONIGHT WENT ABOVE ALL GUIDANCE GIVEN THE MID TO UPPER 30 DEGREE DEWPOINTS RETURNING DURING THE OVERNIGHT HOURS. AS FOR TODAY MID AND HIGH CLOUDS WILL INCREASE FROM THE WEST WITH CLOUDY AFTERNOON SKIES LIKELY FOR ALL OF WESTERN KANSAS BY LATE DAY. NET 24 HOUR TEMPERATURE TRENDS FROM 00Z SATURDAY TO 00Z SUNDAY INDICATE AT 3 TO 5C COOL DOWN WHICH WOULD FAVOR THE WARMER MAV/MOSGUIDE. HOWEVER GIVEN THE INCREASING CLOUD COVER WILL TREND TOWARDS THE COOLER MET GUIDANCE FOR HIGHS WHICH ALSO WAS CLOSE TO THE PREVIOUS FORECAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 407 AM CST SAT DEC 6 2014 A RELATIVELY CHALLENGING FORECAST LIES AHEAD IN THE 24 TO 60 HOUR TIMEFRAME, PRIMARILY WITH RESPECT TO STRATUS DEVELOPMENT, FOG AND POTENTIAL FOR VERY LIGHT SHOWERS. SUNDAY MORNING WILL LIKELY BEGIN WITH WIDESPREAD LOW STRATUS AND AT LEAST SOME POTENTIAL FOR AREAS OF...OR EVEN WIDESPREAD FOG EVEN IF NOT NECESSARILY DENSE. BOUNDARY LAYER MOISTURE ADVECTION SHOULD BE DECREASING AS THE SURFACE WINDS BECOME MORE SOUTHWEST TO WESTERLY AIDING IN DRYING OUT THE CLOUD LAYER BY THE AFTERNOON. ADDITIONALLY, THE NMM/ARW AND NAM INDICATE ANY LIGHT SHOWERS ASSOCIATED WITH THE MID LEVEL WARM ADVECTION/ DEFORMATION AXIS SHOULD BE OVER BY NOON AS WELL. ALTHOUGH SOME FOG DEVELOPMENT IS ALSO POSSIBLE ACROSS THE EASTERNMOST COUNTIES MONDAY MORNING, THE BETTER BOUNDARY LAYER MOISTURE WILL HAVE BEEN REMOVED WHICH WILL NOT FAVOR DEEPER STRATUS DEVELOPMENT. THE PATTERN SUPPORTS FOG AND STRATUS BETTER ONCE AGAIN BY MONDAY NIGHT AND TUESDAY MORNING WITH WHAT THE NAM SHOWS AS AN UPTICK IN SURFACE LAYER MOISTURE ALONG A COLD FRONTAL BOUNDARY. A CONVINCING SURFACE MOISTURE CONVERGENCE PATTERN SOMEWHERE ROUGHLY FROM NORTHERN OKLAHOMA THROUGH EAST CENTRAL COLORADO COULD RESULT. DECENT AGREEMENT ACROSS MODEL DATA AND MOS EXISTS WITH RESPECT TO THE DAILY HIGHS SUNDAY THROUGH TUESDAY, MAINLY IN THE MID 50S TO AROUND 60 FAR WEST. TEMPERATURES WILL WARM FASTEST WEST OF HIGHWAY 283 AS THE STRATUS ERODES SUNDAY. TUESDAY MAY BRING COOLER TEMPERATURES BEHIND THE COOL BOUNDARY ESPECIALLY IN LOCATIONS LIKE HAYS AND STAFFORD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 559 AM CST SAT DEC 6 2014 IFR STRATUS WAS RAPIDLY ADVANCING WESTWARD ACROSS SOUTH CENTRAL KANSAS THIS MORNING. THE HRRR HAD A REASIONABLE HANDLE ON THE AREAL COVERAGE AND SPATIAL TRENDS. WITH SUCH UNCERTAINTY IN THE IMPACTS FOR KDDC, WE`VE ADDED A TEMPO PERIOD FOR 500 FT CIELINGS FOR THE NEXT 3 HOURS WHICH MIGHT BE AMENDED WITHIN THAT TIMEFRAME. VFR CONDITIONS SHOULD THEN PREVAIL AT LEAST UNTIL THE OVENIGHT HOURS WHEN STRATUS AND FOG MAY REDEVELOP. && .PRELIMINARY POINT TEMPS/POPS... DDC 47 37 58 34 / 0 0 20 0 GCK 48 38 59 29 / 0 0 10 0 EHA 53 41 62 35 / 0 0 10 0 LBL 51 39 59 31 / 0 0 10 0 HYS 45 34 54 35 / 0 0 20 0 P28 47 37 54 35 / 0 0 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JJOHNSON SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
601 AM CST SAT DEC 6 2014 ...UPDATED AVIATION... .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 210 AM CST SAT DEC 6 2014 A SOUTHEASTERLY FLOW WILL DEVELOP BY LATE AFTERNOON AS A TROUGH OF LOW PRESSURE BEGINS DEEPENS ALONG THE LEE OF THE ROCKIES AND A SURFACE HIGH MOVES EAST TOWARDS THE MID MISSISSIPPI VALLEY. NAM, RAP, NMM, AND ARW WERE ALL IN GOOD AGREEMENT WITH MORE HUMID AIR IN LOWER LEVELS SPREADING BACK INTO SOUTHWEST KANSAS BY EARLY TONIGHT AS THIS SOUTHEASTERLY FLOW DEVELOPS. BASED ON THE AGREEMENT BETWEEN THE NEAR TERM MODELS AND EVEN RUN TO RUN CONSISTENCY WILL EXPAND THE FOG POTENTIAL ACROSS ALL OF WESTERN KANSAS TONIGHT BASED ON INCREASING LOW LEVEL MOISTURE AND UPSLOPE FLOW. DENSE FOG ALSO MAY BE POSSIBLE AFTER MIDNIGHT EAST OF HIGHWAY 283 GIVEN THE LIGHTER LOW LEVEL WINDS. DEPTH OF THIS LOW LEVEL MOISTURE WILL STAY BELOW 3000FT AGL SO AM NOT ANTICIPATING DRIZZLE DEVELOPMENT. HOWEVER WITH WARM AIR ADVECTION, MOISTURE, AND WEAK ISENTROPIC LIFT DEVELOPING AHEAD OF AN UPPER LEVEL TROUGH ACROSS SOUTH CENTRAL AND NORTH CENTRAL KANSAS WILL GO AHEAD AND INSERT A CHANCE FOR SPRINKLES OR EVEN AN ISOLATED RAIN SHOWER. AS FOR LOWS TONIGHT WENT ABOVE ALL GUIDANCE GIVEN THE MID TO UPPER 30 DEGREE DEWPOINTS RETURNING DURING THE OVERNIGHT HOURS. AS FOR TODAY MID AND HIGH CLOUDS WILL INCREASE FROM THE WEST WITH CLOUDY AFTERNOON SKIES LIKELY FOR ALL OF WESTERN KANSAS BY LATE DAY. NET 24 HOUR TEMPERATURE TRENDS FROM 00Z SATURDAY TO 00Z SUNDAY INDICATE AT 3 TO 5C COOL DOWN WHICH WOULD FAVOR THE WARMER MAV/MOSGUIDE. HOWEVER GIVEN THE INCREASING CLOUD COVER WILL TREND TOWARDS THE COOLER MET GUIDANCE FOR HIGHS WHICH ALSO WAS CLOSE TO THE PREVIOUS FORECAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 407 AM CST SAT DEC 6 2014 A RELATIVELY CHALLENGING FORECAST LIES AHEAD IN THE 24 TO 60 HOUR TIMEFRAME, PRIMARILY WITH RESPECT TO STRATUS DEVELOPMENT, FOG AND POTENTIAL FOR VERY LIGHT SHOWERS. SUNDAY MORNING WILL LIKELY BEGIN WITH WIDESPREAD LOW STRATUS AND AT LEAST SOME POTENTIAL FOR AREAS OF...OR EVEN WIDESPREAD FOG EVEN IF NOT NECESSARILY DENSE. BOUNDARY LAYER MOISTURE ADVECTION SHOULD BE DECREASING AS THE SURFACE WINDS BECOME MORE SOUTHWEST TO WESTERLY AIDING IN DRYING OUT THE CLOUD LAYER BY THE AFTERNOON. ADDITIONALLY, THE NMM/ARW AND NAM INDICATE ANY LIGHT SHOWERS ASSOCIATED WITH THE MID LEVEL WARM ADVECTION/ DEFORMATION AXIS SHOULD BE OVER BY NOON AS WELL. ALTHOUGH SOME FOG DEVELOPMENT IS ALSO POSSIBLE ACROSS THE EASTERNMOST COUNTIES MONDAY MORNING, THE BETTER BOUNDARY LAYER MOISTURE WILL HAVE BEEN REMOVED WHICH WILL NOT FAVOR DEEPER STRATUS DEVELOPMENT. THE PATTERN SUPPORTS FOG AND STRATUS BETTER ONCE AGAIN BY MONDAY NIGHT AND TUESDAY MORNING WITH WHAT THE NAM SHOWS AS AN UPTICK IN SURFACE LAYER MOISTURE ALONG A COLD FRONTAL BOUNDARY. A CONVINCING SURFACE MOISTURE CONVERGENCE PATTERN SOMEWHERE ROUGHLY FROM NORTHERN OKLAHOMA THROUGH EAST CENTRAL COLORADO COULD RESULT. DECENT AGREEMENT ACROSS MODEL DATA AND MOS EXISTS WITH RESPECT TO THE DAILY HIGHS SUNDAY THROUGH TUESDAY, MAINLY IN THE MID 50S TO AROUND 60 FAR WEST. TEMPERATURES WILL WARM FASTEST WEST OF HIGHWAY 283 AS THE STRATUS ERODES SUNDAY. TUESDAY MAY BRING COOLER TEMPERATURES BEHIND THE COOL BOUNDARY ESPECIALLY IN LOCATIONS LIKE HAYS AND STAFFORD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 559 AM CST SAT DEC 6 2014 IFR STRATUS WAS RAPIDLY ADVANCING WESTWARD ACROSS SOUTH CENTRAL KANSAS THIS MORNING. THE HRRR HAD A REASIONABLE HANDLE ON THE AREAL COVERAGE AND SPATIAL TRENDS. WITH SUCH UNCERTAINTY IN THE IMPACTS FOR KDDC, WE`VE ADDED A TEMPO PERIOD FOR 500 FT CIELINGS FOR THE NEXT 3 HOURS WHICH MIGHT BE AMENDED WITHIN THAT TIMEFRAME. VFR CONDITIONS SHOULD THEN PREVAIL AT LEAST UNTIL THE OVENIGHT HOURS WHEN STRATUS AND FOG MAY REDEVELOP. && .PRELIMINARY POINT TEMPS/POPS... DDC 47 37 58 34 / 0 10 20 0 GCK 48 38 59 29 / 0 10 10 0 EHA 53 41 62 35 / 0 10 10 0 LBL 51 39 59 31 / 0 10 10 0 HYS 45 34 54 35 / 0 10 20 0 P28 47 37 54 35 / 10 10 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1018 AM EST SAT DEC 6 2014 .SYNOPSIS... CROSSING LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE UPPER OHIO VALLEY REGION INTO THIS EVENING. HIGH PRESSURE WILL GIVE A DRY DAY SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... MID MORNING UPDATE TO SLOW TIMING FOR RAIN TO END BASED ON LATEST RADAR TRENDS AND INCOMING 12Z MODELS. STILL A CHANCE FOR SLEET TO MIX IN FAR NORTH THIS AFTERNOON BUT NOTHING OF CONSEQUENCE. HOURLY TEMPERATURES AND WINDS ADJUSTED TOWARD NEWEST LAMP GUIDANCE. WINDS WERE INCREASED ESPECIALLY THIS EVENING AS SURFACE LOW PUSHES EAST. PREVIOUS BELOW. ADDITIONAL BASIN AVG FORECAST RAINFALL WAS GENLY PROGGED AT APPROX A HALF TO THREE QUARTERS OF AN INCH USING SMOOTHED RFC GUIDANCE AND MORE REASONABLE RAP AND GFS ASCENT FIELDS...A HEALTHY AND PROLONGED RAINFALL THAT IS NOT EXPECTED TO CAUSE PROBLEMS. PASSAGE OF THE LOW WL INITIATE THE COLD FRONTAL INVASION LTR TDA AND INTO THE EVE. RESIDUAL RAIN WL THUS TURN TO SNOW LATE IN THE DAY...BUT RAPIDLY INCRSG SBSDNC/LOW INVERSION LVLS WL ENSURE A LACK OF ACCUMULATION POTENTIAL. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... RMNG SHWRS OF RAIN AND SNOW WL CONT TO DCRS IN COVERAGE THIS EVE. BLDG HIGH PRES THEREAFTER WL MAINTAIN DRY WEA UNTIL THE APCH OF THE NXT UPR TROF LATE ON MONDAY. SRN STREAM SHRTWV THROUGH THAT TROF IS CURRENTLY PROGGED TO SPIN UP A COASTAL LOW BY MONDAY...NEWD PROGRESS OF WHICH IS CURRENTLY PROGGED TO RMN SUFFICIENTLY E TO FOREGO PROBLEM CONTRIBUTION FOR THE UPR OH REGION. NEVERTHELESS...PCPN CHCS WL INCRS ON MON NGT INTO TUESDAY AS ISENTROPIC LIFT...WARM MOIST ADVCTN DVLPS ON THE ERN FLANKS OF THE HIGH AMPLITUDE ERN CONUS TROF. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A DEEP ERN CONUS TROF IS PROGGED TO PERSIST THRU ERLY INTO THE WKEND AS COASTAL SFC LOW PRES TRACKS UP THE E COAST. FCST SNW SHWR CHCS INTO WED NGT UNTIL THE LOW AND UPR SPPRT EXITS THE RGN. A WK SRTWV IS PROGGED TO ROTATE THRU THE GT LKS ARND THE MAIN TROF FRI THOUGH WITH BLDG SFC HIGH PRES UNDER THE TROF KEPT A DRY FCST. BLO SEASONAL TEMPS SHOULD RTN TO NR AVG BY LT WK. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... WDSPRD IFR/OCNL LIFR CONDS ARE EXPD TO CONT TDA AS UPR OH VLY LOW PRES BRINGS RAIN TO THE RGN. THE EXCEPTION IS MGW AND LBE WHERE OCNL MVFR IS EXPD ERLY...WITH CONDS DCRG TO IFR BY MID TO LT MRNG AS MORE FAVORABLE LLVL MOISTURE ADVECTS OVR THOSE SITES. INCRG NRLY WNDS AND COND IMPROVEMENT TO LOW END MVFR ARE EXPD BY THIS EVE AS THE SFC LOW SHIFTS E AND RAIN TAPERS OFF...WITH SKIES EVENTUALLY SCT OUT TWD SUNRISE SUN MRNG. OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RSTRNS ARE EXPD MON NGT THRU WED AS LOW PRES BRINGS SNW SHWRS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
638 AM EST SAT DEC 6 2014 .SYNOPSIS... CROSSING LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE UPPER OHIO VALLEY REGION TODAY. && .NEAR TERM /THROUGH TONIGHT/... NO MAJOR CHANGES WERE NEEDED FOR THE PRE DAWN UPDATE AS LOW PRES MOVG UP THE OHIO VALLEY WL MAINTAIN RAIN ACROSS THE REGION INTO THE AFTERNOON. ADDITIONAL BASIN AVG FORECAST RAINFALL WAS GENLY PROGGED AT APPROX A HALF TO THREE QUARTERS OF AN INCH USING SMOOTHED RFC GUIDANCE AND MORE REASONABLE RAP AND GFS ASCENT FIELDS...A HEALTHY AND PROLONGED RAINFALL THAT IS NOT EXPECTED TO CAUSE PROBLEMS. PASSAGE OF THE LOW WL INITIATE THE COLD FRONTAL INVASION LTR TDA AND INTO THE EVE. RESIDUAL RAIN WL THUS TURN TO SNOW LATE IN THE DAY...BUT RAPIDLY INCRSG SBSDNC/LOW INVERSION LVLS WL ENSURE A LACK OF ACCUMULATION POTENTIAL. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... RMNG SHWRS OF RAIN AND SNOW WL CONT TO DCRS IN COVERAGE THIS EVE. BLDG HIGH PRES THEREAFTER WL MAINTAIN DRY WEA UNTIL THE APCH OF THE NXT UPR TROF LATE ON MONDAY. SRN STREAM SHRTWV THROUGH THAT TROF IS CURRENTLY PROGGED TO SPIN UP A COASTAL LOW BY MONDAY...NEWD PROGRESS OF WHICH IS CURRENTLY PROGGED TO RMN SUFFICIENTLY E TO FOREGO PROBLEM CONTRIBUTION FOR THE UPR OH REGION. NEVERTHELESS...PCPN CHCS WL INCRS ON MON NGT INTO TUESDAY AS ISENTROPIC LIFT...WARM MOIST ADVCTN DVLPS ON THE ERN FLANKS OF THE HIGH AMPLITUDE ERN CONUS TROF. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A DEEP ERN CONUS TROF IS PROGGED TO PERSIST THRU ERLY INTO THE WKEND AS COASTAL SFC LOW PRES TRACKS UP THE E COAST. FCST SNW SHWR CHCS INTO WED NGT UNTIL THE LOW AND UPR SPPRT EXITS THE RGN. A WK SRTWV IS PROGGED TO ROTATE THRU THE GT LKS ARND THE MAIN TROF FRI THOUGH WITH BLDG SFC HIGH PRES UNDER THE TROF KEPT A DRY FCST. BLO SEASONAL TEMPS SHOULD RTN TO NR AVG BY LT WK. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... WDSPRD IFR/OCNL LIFR CONDS ARE EXPD TO CONT TDA AS UPR OH VLY LOW PRES BRINGS RAIN TO THE RGN. THE EXCEPTION IS MGW AND LBE WHERE OCNL MVFR IS EXPD ERLY...WITH CONDS DCRG TO IFR BY MID TO LT MRNG AS MORE FAVORABLE LLVL MOISTURE ADVECTS OVR THOSE SITES. INCRG NRLY WNDS AND COND IMPROVEMENT TO LOW END MVFR ARE EXPD BY THIS EVE AS THE SFC LOW SHIFTS E AND RAIN TAPERS OFF...WITH SKIES EVENTUALLY SCT OUT TWD SUNRISE SUN MRNG. OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RSTRNS ARE EXPD MON NGT THRU WED AS LOW PRES BRINGS SNW SHWRS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/07
AREA FORECAST DISCUSSION
NWS BUFFALO NY
705 AM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE PASSING TO THE SOUTH OF THE REGION WILL BRING RAIN WHICH WILL TAPER OFF FROM WEST TO EAST THIS AFTERNOON. HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION SUNDAY AND MONDAY WITH FAIR BUT CHILLY WEATHER. LOW PRESSURE DEVELOPING ACROSS NEW ENGLAND IS LIKELY TO BRING RAIN OR SNOW TO OUR REGION ON TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AT 700 AM...REGIONAL RADAR IMAGERY SHOWS A LARGE AREA OF PRECIPITATION ACROSS MOST OF THE CWA...WITH THE ONLY DRY AREAS NORTH OF A IAG-ART LINE. THERE WILL CONTINUE TO BE A SHARP CUT OFF ON THE BACK OF THE SYSTEM...WITH AREAS NORTH OF NIAGARA FALLS TO WATERTOWN LIKELY TO STAY DRY WHILE EVERYWHERE ELSE GETS A SOAKING RAIN. IN TERMS OF MODEL GUIDANCE...THE HRRR IS IN LINE WITH MODEL CONSENSUS AND PAINTS A PRETTY REASONABLE PICTURE OF HOW THE EVENT IS LIKELY TO PLAY OUT. PRECIPITATION WILL TAPER OFF FROM WEST TO EAST THIS AFTERNOON. THIS WILL BRING A DECENT AMOUNT OF RAIN TO THE SOUTHERN TIER WITH A CONSENSUS OF HIGH-RES GUIDANCE BRINGING HALF TO THREE-QUARTERS OF AN INCH OF RAIN. AMOUNTS WILL TAPER OFF ABRUPTLY NORTH OF THIS...WITH BARELY MEASURABLE AMOUNTS NW OF IAG/ART. AS FOR PRECIPITATION TYPE...TEMPERATURES ARE ABOVE FREEZING IN MOST AREAS WITH ONLY HIGHER TERRAIN IN LEWIS COUNTY STILL BELOW FREEZING WHERE A WINTER WEATHER ADVISORY REMAINS IN PLACE. ELSEWHERE...PRECIPITATION WILL FALL AS RAIN THROUGH THIS MORNING. COLDER AIR (BOTH SURFACE AND ALOFT) WILL BUILD IN WHEN THE LOW PASSES TO THE SOUTH AND SHIFTS WINDS TO THE NORTH THIS AFTERNOON. HOWEVER...THIS WILL ONLY LEAVE A NARROW MARGIN FOR SNOW JUST AS PRECIPITATION IS TAPERING OFF. LITTLE...IF ANY...ACCUMULATION IS EXPECTED BEFORE PRECIPITATION ENDS. THERE WILL ALSO BE AREAS OF FOG THIS MORNING...ESPECIALLY ACROSS HIGHER TERRAIN IN THE SOUTHERN TIER. HIGH PRESSURE WILL BUILD ACROSS THE UPPER LAKES THIS EVENING...THEN GRADUALLY SHIFT INTO ONTARIO AND QUEBEC LATE TONIGHT. THIS WILL BRING COOLER AND DRIER AIR INTO THE REGION TONIGHT. THE NORTHERLY FLOW ACROSS THE LAKES MAY INITIALLY DELAY CLEARING...BUT WITH 850MB TEMPERATURES ONLY -6C...LAKE INDUCED INSTABILITY WILL BE TOO SMALL TO SUPPORT LAKE EFFECT PRECIPITATION AND MARGINAL TO RESULT IN LAKE EFFECT CLOUDS. EXPECT CLOUDS TO LINGER THIS EVENING IN UPSLOPE LOCATIONS...BUT EVENTUALLY SCATTER OUT LATE TONIGHT. EARLIER CLEARING SHOULD ALLOW FOR LOWS 10 TO 15 EAST OF LAKE ONTARIO...WITH UPPER TEENS TO LOWER 20S ELSEWHERE. THERE IS A SMALL CHANCE FOR BLACK ICE IN SPOTS TONIGHT...BUT IT APPEARS WINDS LATE THIS AFTERNOON AND EARLY EVENING SHOULD HELP DRY OUT ROADS IN MANY AREAS BEFORE TEMPERATURES DROP BELOW FREEZING. && .SHORT TERM /SUNDAY THROUGH MONDAY/... FAIR WEATHER IS EXPECTED SUNDAY THROUGH MONDAY NIGHT AS AN AREA OF HIGH PRESSURE CROSSES SOUTHERN CANADA. THIS HIGH PRESSURE...STARTING SUNDAY MORNING TO OUR WEST WILL BRING A LIGHT AND COOL NORTHERLY FLOW ACROSS NEW YORK STATE. THOUGH A GOOD DEAL OF SUNSHINE IS EXPECTED...THESE COOL NORTHERLY WINDS WILL KEEP MOST AREAS IN THE 20S THROUGH THE DAY. SUNDAY NIGHT OUR WINDS WILL VEER AROUND TO EASTERLY AND THEN SOUTHEASTERLY ON MONDAY BEHIND THE BUBBLE OF HIGH PRESSURE. A SEASONABLY COOL SUNDAY NIGHT WILL WARM TO THE MID 30S TO LOWER 40S ACROSS THE REGION MONDAY WITH THE VEERING WINDS. AS SOUTHERLY FLOW ALOFT INCREASES THROUGH THE DAY MONDAY EXPECT CLOUDS TO THICKEN THROUGH THE DAY. A TIGHTENING PRESSURE GRADIENT BETWEEN THE COOLER HIGH PRESSURE AIRMASS TO OUR SOUTHEAST AND A WARMING AIRMASS AHEAD OF AN AREA OF LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL BRING A GUSTY BREEZE ACROSS THE WESTERN AND CENTRAL PART OF NEW YORK STATE. SOUTHEAST WINDS MAY REACH GUSTS 25 TO 35 MPH...AND POSSIBLY NEAR 40 MPH ALONG THE LAKE ERIE SHORELINE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AN INTERESTING WEATHER SYSTEM IS STILL ON TRACK TO EVOLVE MONDAY NIGHT THROUGH WEDNESDAY. GLOBAL MODELS CONTINUE TO STRUGGLE WITH THE FAIRLY COMPLEX EVOLUTION OF THIS SYSTEM. TO APPRECIATE THE COMPLEXITY...THIS SYSTEM IS EXPECTED TO EVOLVE OUT OF A PACIFIC SHORTWAVE CURRENTLY COMING ON SHORE IN THE PAC NORTHWEST ANOTHER WEAK SOUTHERN STREAM SHORTWAVE NEAR SOUTHERN CALIFORNIA AND A HIGH LATITUDE WAVE THAT IS PROGGED TO PHASE WITH BOTH SHORTWAVES OVER THE NORTHEAST CONUS. MODEL TRENDS TODAY HAVE BEEN TOWARD CUTTING OFF AN UPPER-LEVEL LOW OVER NEW ENGLAND RATHER THAN MAINTAINING AN OPEN WAVE. HOWEVER...THIS IS WHERE THE SIMILARITIES IN THE MODELS END. WHILE THE GFS HAS CAUGHT ONTO THE ECMWF TREND OF CUTTING OFF THE LOW...IT REMAINS A FARTHER NORTH SOLUTION...WITH THE LOW CENTERED OVER SOUTHERN CANADA JUST NORTH OF VERMONT BY WEDNESDAY MORNING. THE FARTHER SOUTH ECMWF SOLUTION ACTUALLY CENTERS THE LOW OVER NEW JERSEY BY WEDNESDAY MORNING. GIVEN THE CUT-OFF NATURE OF THIS LOW...NEITHER SOLUTION CONTAINS SIGNIFICANT AMOUNTS OF COLD AIR...BUT THE GFS REMAINS ON THE COOLER SIDE WITH 850MB TEMPS AROUND -10 TO -12 C...COMPARED TO THE EC WHICH IS AROUND -6 TO -8 C. SO WHAT DOES THIS ALL MEAN FOR THE FORECAST? THE OVERALL TREND HAS BEEN TOWARD A WETTER SOLUTION FOR THE FORECAST AREA...AND THUS HAVE INCREASED POPS TO LIKELY TUESDAY AND TUESDAY NIGHT. PRECIPITATION WOULD LIKELY START AS EITHER RAIN OR A RAIN/SNOW MIX MONDAY NIGHT...AND REMAINING A RAIN/SNOW MIX THROUGH THE DAY TUESDAY. THEN WITH COOLER TEMPERATURES FILTERING INTO THE FORECAST AREA TUESDAY INTO TUESDAY NIGHT MIXED PRECIPITATION SHOULD CHANGE OVER TO SNOW WITH PERHAPS SOME LAKE ENHANCEMENT IF THE COLDER GFS SOLUTION VERIFIES. BY WEDNESDAY A COOL...BRISK NORTHWEST FLOW WILL AGAIN KEEP LIKELY SNOW SHOWERS ACROSS THE REGION...ESPECIALLY ACROSS THE UPSLOPE HILLS OF SW NYS AND EASTERN LAKE ONTARIO REGION. WILL RAISE POPS TO LIKELY HERE...AND SLOWLY TAPERING THEM OFF TO JUST CHANCE POPS THURSDAY AS THE COMPLEX AREA OF LOW PRESSURE EXITS EASTWARD. WEDNESDAY AND THURSDAY TEMPERATURES SHOULD AVERAGE JUST BELOW NORMAL WITH THE COOL NW FLOW. TIMING DIFFERENCES REMAIN ON HOW QUICKLY THE CUT OFF LOW WILL MOVE EASTWARD WITH THE EC HOLDING THE LOW BACK THE LONGEST...AND THUS DELAYING THE ONSET OF WARMER TEMPERATURES UNTIL THE START OF THE FOLLOWING WEEK. THE GFS HOWEVER MOVES THE LOW OUT MORE QUICKLY...AND THE AMPLIFYING PATTERN ACROSS THE CONUS WOULD RESULT IN MILD TEMPERATURES ACROSS THE FORECAST AREA BY THE WEEKEND. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AT 12Z...LOW PRESSURE WAS TRACKING TO THE SOUTH OF THE REGION...BRINGING WIDESPREAD RAIN TO AREAS SOUTH OF IAG/ART. CIGS HAVE LOWERED CONSIDERABLY WITH A MIX OF MVFR AND IFR CONDITIONS IN MOST AREAS. A SHIFT TO NORTHERLY WINDS SHOULD CAUSE CIGS TO LOWER...WITH FAIRLY WIDESPREAD IFR CONDITIONS EXPECTED. EVEN LOWER MOISTURE AND FOG IS EXPECTED ACROSS HIGHER TERRAIN SUCH AS JHW. DRIER AIR WILL BUILD IN BEHIND THE LOW...FOLLOWED BY SURFACE HIGH PRESSURE TONIGHT. IFR CIGS WILL GRADUALLY LIFT THIS AFTERNOON...EVENTUALLY RETURNING TO VFR TONIGHT AS DRIER AIR BUILDS IN TONIGHT. OUTLOOK... SUNDAY AND MONDAY...MAINLY VFR. TUESDAY AND WEDNESDAY...MVFR WITH RAIN OR SNOW LIKELY. && .MARINE... WINDS WILL SHIFT TO THE NORTH ONCE LOW PRESSURE PASSES TO OUR SOUTH TODAY. THIS WILL REQUIRE SMALL CRAFT ADVISORIES ON THE SOUTH SHORES OF LAKE ONTARIO LATE TODAY THROUGH EARLY SUNDAY. HAVE ALSO ADDED SMALL CRAFT ADVISORIES TO LAKE ERIE SOUTH OF DUNKIRK...WHERE THE 15 TO 20 KT FLOW SHOULD BE AMPLE TO BUILD WAVES TO 5 FT. HIGH PRESSURE WILL BUILD IN ON SUNDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ008. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST SUNDAY FOR LEZ040. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 10 AM EST SUNDAY FOR LOZ043-044. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST SUNDAY FOR LOZ042. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...THOMAS LONG TERM...CHURCH/THOMAS AVIATION...APFFEL MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
708 AM EST SAT DEC 6 2014 .SYNOPSIS...A SHORTWAVE TROUGH INITIALLY OVER THE MID MS AND TN VALLEYS WILL AMPLIFY ACROSS THE SOUTHERN APPALACHIANS AND CAROLINAS THROUGH TONIGHT. AN ACCOMPANYING SURFACE LOW OVER THE LOWER OH AND TN VALLEY WILL RE-DEVELOP OVER VA/NC TODAY...THEN BEGIN TO INTENSIFY AS IT APPROACHES A COASTAL FRONT ALONG THE NC COAST THIS EVENING- TONIGHT. MEANWHILE...ARCTIC HIGH PRESSURE WILL STRENGTHEN AS IT MIGRATES FROM THE NORTHERN PLAINS TO NEW ENGLAND...THE SOUTHERN PERIPHERY OF WHICH WILL RIDGE SOUTH INTO NC LATE TONIGHT THROUGH SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM SATURDAY... A COASTAL FRONT ALONG THE SOUTHEAST AND MIDDLE ATLANTIC COASTS HAS CAUSED A PIECE OF THE 1040 MB MODIFIED ARCTIC CENTERED NEAR NEWFOUNDLAND TO BREAK OFF OVER THE CAROLINAS THIS MORNING...AND THIS 1027 MB HIGH WILL LIKELY ESTABLISH A SHORT-LIVED IN-SITU CAD EVENT OVER AT LEAST THE WESTERN PIEDMONT TODAY. WHETHER OR NOT THE WEDGE IS ESTABLISHED EAST ACROSS THE REMAINDER OF CENTRAL NC IS MORE IN QUESTION...SINCE IT SEEMS THE UPSTREAM PRE-FRONTAL BAND OF RAIN NOW CROSSING THE SOUTHERN-CENTRAL APPALACHIANS HAS BEEN FALLING MOSTLY FROM MID LEVEL CEILINGS...AND AS SUCH...WOULD MAKE IT LESS LIKELY TO FULLY SATURATE THE LOW LEVELS AND HELP ESTABLISH A WEDGE. IN FACT...BOTH THE RAP AND HRRR SUGGEST THE INITIAL BAND OF IFR-MVFR CEILINGS CENTERED FROM NEAR CAE TO RDU TO RIC THIS MORNING WILL DRIFT EAST THROUGH MIDDAY...AND PROVIDE FOR A PERIOD OF MOSTLY MID- HIGH LEVEL CLOUDS AND MODEST INSOLATION DURING THE MIDDAY-EARLY AFTERNOON HOURS. THE MAIN SENSIBLE WEATHER IMPACT WITH THIS UNCERTAINTY REGARDS TEMPERATURES...WHICH WOULD BE HELD IN THE MID- UPPER 40S OVER THE NW PIEDMONT (SIMILAR TO FRI) TO GENERALLY MID 50S ELSEWHERE IF IN-SITU WEDGING BECAME ESTABLISHED. HOWEVER...BASED ON UPSTREAM OBSERVATIONS OF RAIN FROM MOSTLY MID CLOUDS...WILL TREND HIGH TEMPS TOWARD SOME MODEST INSOLATION...WITH HIGHS RANGING FROM THE MIDDLE 50S TO NEAR 60 DEGREES...EXCEPT AROUND 50 DEGREES OR SO IN THE WESTERN PIEDMONT WHERE THE OPPORTUNITY FOR INSOLATION WILL BE MORE LIMITED BETWEEN THE PRE-FRONTAL RAIN BAND...AND A TRAILING SEPARATE AREA OF SHALLOW CONVECTIVE PRECIPITATION FORECAST TO MOVE ACROSS THE AREA LATER THIS AFTERNOON AND EVENING. THAT TRAILING PRECIPITATION WILL BE FUELED BY SUBSTANTIAL COOLING ALOFT ACCOMPANYING A PARENT SHORTWAVE TROUGH ALOFT...ATOP A WARM AND MOIST...40 KT LLJ. THE ASSOCIATED STRONG DIFFERENTIAL THERMAL ADVECTION WILL CAUSE H85-5 LAPSE RATES TO STEEPEN IN EXCESS OF 6.5 C/KM OVER CENTRAL NC...COINCIDENT WITH 50-80 METER MID LEVEL HEIGHT FALLS ACCOMPANYING THE PARENT SHORTWAVE TROUGH ALOFT. FORECAST GUIDANCE CONTINUES TO SUGGEST THAT A POCKET OF UP TO A FEW HUNDRED J/KG OF MUCAPE WILL CONSEQUENTLY DEVELOP OVER OUR AREA THIS AFTERNOON...WHICH WILL SUPPORT THE EASTWARD PROGRESSION AND/OR RE- DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON. THOUGH SHOWERS AND ISOLATED STORMS WILL MOVE EAST WITH THE PASSAGE OF THE OCCLUDED/COLD FRONT THIS EVENING...THE DEEPENING OF A SURFACE LOW AS IT ENCOUNTERS THE COASTAL FRONT WILL MAINTAIN A MOIST NNE FLOW THAT WILL LIKELY RESULT IN CONSIDERABLE LOW OVERCAST AND AREAS OF LIGHT RAIN OR DRIZZLE...WHICH WILL ONLY SLOWLY EDGE EASTWARD THROUGH SUN MORNING...PARTICULARLY OVER THE EASTERN TWO THIRDS OF THE CWFA. IT WILL ALSO BECOME NOTICEABLY BLUSTERY IN STRONG CAA AS THE LOW LEVEL RIDGING BUILDS EAST OF THE APPALACHIANS...WITH LOWS MOSTLY IN THE LOWER TO MIDDLE 40S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 340 AM SATURDAY... SUNDAY AND SUNDAY NIGHT: BRIEF SHORTWAVE RIDGING WILL BUILD EAST ACROSS OUR REGION AND CAUSE STRONG ARCTIC HIGH PRESSURE CENTERED OVER NEW ENGLAND TO RIDGE DOWN THE EAST COAST THIS PERIOD...IN ADVANCE OF A PAIR OF PHASED (OR NEARLY SO) SHORTWAVE TROUGHS FORECAST TO AMPLIFY FROM THE PLAINS TO THE MS VALLEY THROUGH SUN NIGHT. DESPITE MAINLY CLEAR SKIES...EXCEPT SOME LINGERING LOW CLOUDS OVER EASTERN NC...A BRISK AND GUSTY NE WIND WILL RESULT IN RATHER CHILLY CONDITIONS...WITH HIGHS MOSTLY IN THE MID-UPPER 40S (TO NEAR 50 SOUTH). THE AMPLIFICATION OF THE AFOREMENTIONED TROUGHS ALOFT WILL CAUSE THE LOW LEVEL FLOW (925 MB) TO ASSUME AN INCREASINGLY EASTERLY COMPONENT (TOWARD THE PRESSURE FALLS ACCOMPANYING HE APPROACHING TROUGH)...SUCH THAT THE LOW CLOUDS OVER THE EASTERN PART OF THE STATE WILL DEVELOP/ADVECT WSW ACROSS CENTRAL NC THROUGH MON MORNING. LOWS RANGING FROM THE UPPER 20S IN THE WEST TO MIDDLE 30S EAST. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 335 AM SATURDAY... CONFIDENCE IS LOWER THAN DESIRED FOR A DAY 3 (MONDAY) FORECAST DUE TO MODEL DIFFERENCES REGARDING THE INTERACTION OF NORTHERN AND SOUTHERN STREAM SHORTWAVES AS THEY CROSS THE CENTRAL AND EASTERN US. MODELS HAVE BEEN COMING INTO A LITTLE BETTER AGREEMENT...SHOWING THE LEAD SOUTHERN STREAM SHORTWAVE MOVING FROM THE DEEP SOUTH ACROSS THE CAROLINAS ON MONDAY...WITH A NORTHERN STREAM WAVE TO DIVE SOUTH ACROSS THE REGION ON TUESDAY. IN RESPONSE TO THE LEAD WAVE...A SURFACE LOW OFF THE SOUTHEAST COAST WILL RE-INTENSIFY AND LIFT NORTH ALONG THE EAST COAST. THE NAM AND CANADIAN ARE STRONG OUTLIERS REGARDING THE STRENGTH OF THE LOW AND ASSOCIATED PRECEDING EASTERLY FLOW...PRODUCING HEAVIER PRECIP EARLIER ON MONDAY. THE ECMWF IS A LITTLE MORE AMPLIFIED WITH THE LEAD WAVE...RESULTING MORE PRECIP THAN THE GFS...BUT STILL RELATIVELY LIGHT AND NOT UNTIL MONDAY AFTERNOON. THIS HAS SOME SIGNIFICANCE...AS A STRONG 1040+ MB SURFACE HIGH EXTENDING INTO THE NC FROM NEW ENGLAND WILL BE RETREATING DURING THE DAY BUT WOULD OFFER SOME PTYPE CONCERNS IN THE NORTHWEST PIEDMONT WITH PRECIP EARLY MONDAY MORNING...AS THE NAM DEPICTS. HOWEVER THIS IS DISCOUNTED AT THIS TIME. WILL SHOW POPS INCREASING BY MIDDAY...SLIGHT CHANCE WEST TO CHANCE IN THE EAST...ENDING FROM SOUTHWEST TO NORTHEAST MONDAY NIGHT AS THE SURFACE LOW MOVES OFF TO THE NORTHEAST. THE QPF FORECAST IS FOR LESS THAN A TENTH OF AN INCH...BUT WOULDNT BE SURPRISED TO SEE MODELS PRODUCE MORE PRECIP IN LATER RUNS. HAVE LOWERED HIGHS A FEW DEGREES ACROSS THE PIEDMONT BASED ON INCREASING POTENTIAL FOR PRECIP...RANGING FROM LOWER 40S NORTHWEST TO NEAR 50 SOUTHEAST. LOWS MONDAY NIGHT IN THE LOWER 30S NORTHEAST TO UPPER 30S SOUTHEAST. A STRONG NORTHERN STREAM SHORTWAVE WILL DIVE ACROSS NC ON TUESDAY....FOLLOWED BY A REINFORCING SHOT OF COLD ADVECTION TUESDAY NIGHT. THE ECMWF SPITS OUT SOME VERY LIGHT QPF ACROSS THE NORTH TUESDAY AFTERNOON...BUT WILL HOLD OFF ON INTRODUCING POPS AS MOISTURE WILL BE LIMITED. HIGH PRESSURE IS THEN FORECAST TO BUILD ACROSS THEN BUILD SLOWLY ACROSS THE SOUTHEAST BETWEEN AN UPPER LOW THAT CLOSES OFF OVER NEW ENGLAND AND RIDGING OVER THE CENTRAL US. TEMPS MAY SLOWLY MODERATE BUT WILL REMAIN AT OR JUST BELOW NORMAL. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 700 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS WILL LIKELY SHIFT EAST OF RDU/FAY/RWI BETWEEN 15-18Z...AS THE FLOW IN THAT LAYER VEERS FROM SOUTHERLY TO SOUTHWESTERLY...AFTER WHICH TIME A SEVERAL HOUR PERIOD OF VFR CONDITIONS ARE PROBABLE DURING THE MIDDAY TO EARLY AFTERNOON HOURS. MEANWHILE...A PRE-FRONTAL BAND OF RAIN...FALLING FROM MOSTLY VFR CEILINGS BUT PRODUCING MVFR SURFACE VISIBILITY RESTRICTIONS...WILL MOVE EAST AND ARRIVE AT RDU AND FAY BETWEEN 14-15Z AND RWI BETWEEN 16-18Z...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-23Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING BRISK NW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB- VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...BLS AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
706 AM EST SAT DEC 6 2014 .SYNOPSIS...A SHORTWAVE TROUGH INITIALLY OVER THE MID MS AND TN VALLEYS WILL AMPLIFY ACROSS THE SOUTHERN APPALACHIANS AND CAROLINAS THROUGH TONIGHT. AN ACCOMPANYING SURFACE LOW OVER THE LOWER OH AND TN VALLEY WILL RE-DEVELOP OVER VA/NC TODAY...THEN BEGIN TO INTENSIFY AS IT APPROACHES A COASTAL FRONT ALONG THE NC COAST THIS EVENING- TONIGHT. MEANWHILE...ARCTIC HIGH PRESSURE WILL STRENGTHEN AS IT MIGRATES FROM THE NORTHERN PLAINS TO NEW ENGLAND...THE SOUTHERN PERIPHERY OF WHICH WILL RIDGE SOUTH INTO NC LATE TONIGHT THROUGH SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM SATURDAY... A COASTAL FRONT ALONG THE SOUTHEAST AND MIDDLE ATLANTIC COASTS HAS CAUSED A PIECE OF THE 1040 MB MODIFIED ARCTIC CENTERED NEAR NEWFOUNDLAND TO BREAK OFF OVER THE CAROLINAS THIS MORNING...AND THIS 1027 MB HIGH WILL LIKELY ESTABLISH A SHORT-LIVED IN-SITU CAD EVENT OVER AT LEAST THE WESTERN PIEDMONT TODAY. WHETHER OR NOT THE WEDGE IS ESTABLISHED EAST ACROSS THE REMAINDER OF CENTRAL NC IS MORE IN QUESTION...SINCE IT SEEMS THE UPSTREAM PRE-FRONTAL BAND OF RAIN NOW CROSSING THE SOUTHERN-CENTRAL APPALACHIANS HAS BEEN FALLING MOSTLY FROM MID LEVEL CEILINGS...AND AS SUCH...WOULD MAKE IT LESS LIKELY TO FULLY SATURATE THE LOW LEVELS AND HELP ESTABLISH A WEDGE. IN FACT...BOTH THE RAP AND HRRR SUGGEST THE INITIAL BAND OF IFR-MVFR CEILINGS CENTERED FROM NEAR CAE TO RDU TO RIC THIS MORNING WILL DRIFT EAST THROUGH MIDDAY...AND PROVIDE FOR A PERIOD OF MOSTLY MID- HIGH LEVEL CLOUDS AND MODEST INSOLATION DURING THE MIDDAY-EARLY AFTERNOON HOURS. THE MAIN SENSIBLE WEATHER IMPACT WITH THIS UNCERTAINTY REGARDS TEMPERATURES...WHICH WOULD BE HELD IN THE MID- UPPER 40S OVER THE NW PIEDMONT (SIMILAR TO FRI) TO GENERALLY MID 50S ELSEWHERE. BASED ON UPSTREAM OBSERVATIONS OF RAIN FROM MOSTLY MID CLOUDS...WILL TREND HIGH TEMPS TOWARD SOME MODEST INSOLATION...WITH HIGHS RANGING FROM THE MIDDLE 50S TO NEAR 60 DEGREES...EXCEPT AROUND 50 DEGREES OR SO IN THE WESTERN PIEDMONT WHERE THE OPPORTUNITY FOR INSOLATION WILL BE MORE LIMITED BETWEEN THE PRE-FRONTAL RAIN BAND...AND A TRAILING SEPARATE AREA OF SHALLOW CONVECTIVE PRECIPITATION FORECAST TO MOVE ACROSS THE AREA LATER THIS AFTERNOON. THAT TRAILING PRECIPITATION WILL BE FUELED BY SUBSTANTIAL COOLING ALOFT ACCOMPANYING A PARENT SHORTWAVE TROUGH ALOFT...ATOP A WARM AND MOIST...40 KT LLJ. THE ASSOCIATED STRONG DIFFERENTIAL THERMAL ADVECTION WILL CAUSE H85-5 LAPSE RATES TO STEEPEN IN EXCESS OF 6.5 C/KM OVER CENTRAL NC...COINCIDENT WITH 50-80 METER MID LEVEL HEIGHT FALLS ACCOMPANYING THE PARENT SHORTWAVE TROUGH ALOFT. FORECAST GUIDANCE CONTINUES TO SUGGEST THAT A POCKET OF UP TO A FEW HUNDRED J/KG OF MUCAPE WILL CONSEQUENTLY DEVELOP OVER OUR AREA THIS AFTERNOON...WHICH WILL SUPPORT THE EASTWARD PROGRESSION AND/OR RE- DEVELOPMENT OF NUMEROUS TO WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON. THOUGH SHOWERS AND ISOLATED STORMS WILL MOVE EAST WITH THE PASSAGE OF A THE OCCLUDED/COLD FRONT THIS EVENING...THE DEEPENING OF A SURFACE LOW AS IT ENCOUNTERS THE COASTAL FRONT WILL MAINTAIN A MOIST NNE FLOW THAT WILL LIKELY RESULT IN CONSIDERABLE LOW OVERCAST AND AREAS OF LIGHT RAIN OR DRIZZLE...WHICH WILL ONLY SLOWLY EDGE EASTWARD THROUGH SUN MORNING...PARTICULARLY OVER THE EASTERN TWO THIRDS OF THE CWFA. IT WILL ALSO BECOME NOTICEABLY BLUSTERY IN STRONG CAA AS THE LOW LEVEL RIDGING BUILDS EAST OF THE APPALACHIANS...WITH LOWS MOSTLY IN THE LOWER TO MIDDLE 40S. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 340 AM SATURDAY... SUNDAY AND SUNDAY NIGHT: BRIEF SHORTWAVE RIDGING WILL BUILD EAST ACROSS OUR REGION AND CAUSE STRONG ARCTIC HIGH PRESSURE CENTERED OVER NEW ENGLAND TO RIDGE DOWN THE EAST COAST THIS PERIOD...IN ADVANCE OF A PAIR OF PHASED (OR NEARLY SO) SHORTWAVE TROUGHS FORECAST TO AMPLIFY FROM THE PLAINS TO THE MS VALLEY THROUGH SUN NIGHT. DESPITE MAINLY CLEAR SKIES...EXCEPT SOME LINGERING LOW CLOUDS OVER EASTERN NC...A BRISK AND GUSTY NE WIND WILL RESULT IN RATHER CHILLY CONDITIONS...WITH HIGHS MOSTLY IN THE MID-UPPER 40S (TO NEAR 50 SOUTH). THE AMPLIFICATION OF THE AFOREMENTIONED TROUGHS ALOFT WILL CAUSE THE LOW LEVEL FLOW (925 MB) TO ASSUME AN INCREASINGLY EASTERLY COMPONENT (TOWARD THE PRESSURE FALLS ACCOMPANYING HE APPROACHING TROUGH)...SUCH THAT THE LOW CLOUDS OVER THE EASTERN PART OF THE STATE WILL DEVELOP/ADVECT WSW ACROSS CENTRAL NC THROUGH MON MORNING. LOWS RANGING FROM THE UPPER 20S IN THE WEST TO MIDDLE 30S EAST. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 335 AM SATURDAY... CONFIDENCE IS LOWER THAN DESIRED FOR A DAY 3 (MONDAY) FORECAST DUE TO MODEL DIFFERENCES REGARDING THE INTERACTION OF NORTHERN AND SOUTHERN STREAM SHORTWAVES AS THEY CROSS THE CENTRAL AND EASTERN US. MODELS HAVE BEEN COMING INTO A LITTLE BETTER AGREEMENT...SHOWING THE LEAD SOUTHERN STREAM SHORTWAVE MOVING FROM THE DEEP SOUTH ACROSS THE CAROLINAS ON MONDAY...WITH A NORTHERN STREAM WAVE TO DIVE SOUTH ACROSS THE REGION ON TUESDAY. IN RESPONSE TO THE LEAD WAVE...A SURFACE LOW OFF THE SOUTHEAST COAST WILL RE-INTENSIFY AND LIFT NORTH ALONG THE EAST COAST. THE NAM AND CANADIAN ARE STRONG OUTLIERS REGARDING THE STRENGTH OF THE LOW AND ASSOCIATED PRECEDING EASTERLY FLOW...PRODUCING HEAVIER PRECIP EARLIER ON MONDAY. THE ECMWF IS A LITTLE MORE AMPLIFIED WITH THE LEAD WAVE...RESULTING MORE PRECIP THAN THE GFS...BUT STILL RELATIVELY LIGHT AND NOT UNTIL MONDAY AFTERNOON. THIS HAS SOME SIGNIFICANCE...AS A STRONG 1040+ MB SURFACE HIGH EXTENDING INTO THE NC FROM NEW ENGLAND WILL BE RETREATING DURING THE DAY BUT WOULD OFFER SOME PTYPE CONCERNS IN THE NORTHWEST PIEDMONT WITH PRECIP EARLY MONDAY MORNING...AS THE NAM DEPICTS. HOWEVER THIS IS DISCOUNTED AT THIS TIME. WILL SHOW POPS INCREASING BY MIDDAY...SLIGHT CHANCE WEST TO CHANCE IN THE EAST...ENDING FROM SOUTHWEST TO NORTHEAST MONDAY NIGHT AS THE SURFACE LOW MOVES OFF TO THE NORTHEAST. THE QPF FORECAST IS FOR LESS THAN A TENTH OF AN INCH...BUT WOULDNT BE SURPRISED TO SEE MODELS PRODUCE MORE PRECIP IN LATER RUNS. HAVE LOWERED HIGHS A FEW DEGREES ACROSS THE PIEDMONT BASED ON INCREASING POTENTIAL FOR PRECIP...RANGING FROM LOWER 40S NORTHWEST TO NEAR 50 SOUTHEAST. LOWS MONDAY NIGHT IN THE LOWER 30S NORTHEAST TO UPPER 30S SOUTHEAST. A STRONG NORTHERN STREAM SHORTWAVE WILL DIVE ACROSS NC ON TUESDAY....FOLLOWED BY A REINFORCING SHOT OF COLD ADVECTION TUESDAY NIGHT. THE ECMWF SPITS OUT SOME VERY LIGHT QPF ACROSS THE NORTH TUESDAY AFTERNOON...BUT WILL HOLD OFF ON INTRODUCING POPS AS MOISTURE WILL BE LIMITED. HIGH PRESSURE IS THEN FORECAST TO BUILD ACROSS THEN BUILD SLOWLY ACROSS THE SOUTHEAST BETWEEN AN UPPER LOW THAT CLOSES OFF OVER NEW ENGLAND AND RIDGING OVER THE CENTRAL US. TEMPS MAY SLOWLY MODERATE BUT WILL REMAIN AT OR JUST BELOW NORMAL. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 700 AM SATURDAY... COMPLEX FORECAST FOR THIS TAF PERIOD...AND BEYOND THROUGH EARLY THIS UPCOMING WEEK. AN AXIS OF IFR-MVFR STRATUS WILL LIKELY SHIFT EAST OF RDU/FAY/RWI BETWEEN 15-18Z...AS THE FLOW IN THAT LAYER VEERS FROM SOUTHERLY TO SOUTHWESTERLY...AFTER WHICH TIME A SEVERAL HOUR PERIOD OF VFR CONDITIONS ARE PROBABLE DURING THE MIDDAY TO EARLY AFTERNOON HOURS. MEANWHILE...A PRE-FRONTAL BAND OF RAIN...FALLING FROM MOSTLY VFR CEILINGS BUT PRODUCING MVFR SURFACE VISIBILITY RESTRICTIONS...WILL MOVE EAST AND ARRIVE AT RDU AND FAY BETWEEN 14-15Z AND RWI BETWEEN 16-18Z...BASICALLY ON THE HEELS OF THE DEPARTING INITIAL BAND OF MVFR CEILINGS. THEN YET A THIRD REGIME OF IFR-MVFR CONDITIONS AND NUMEROUS TO WIDESPREAD SHOWERS (AND ISOLATED THUNDERSTORMS) WILL SWEEP EAST INTO OUR AREA BETWEEN 17-19Z AT WESTERN TERMINALS TO BETWEEN 20-23Z AT EASTERN ONES. THE PASSAGE OF A COLD FRONT AND FOLLOWING BRISK NW BREEZE WILL HELP SCOUR AND LIFT THE CLOUD LAYER...PARTICULARLY AT TRIAD TERMINALS THIS EVENING...THOUGH SUB- VFR CONDITIONS AND AREAS OF LIGHT RAIN OR DRIZZLE ARE APT TO LINGER THROUGHOUT THE NIGHT...ESPECIALLY AT RDU/RWI/FAY. OUTLOOK: IN THE WAKE OF THE AFOREMENTIONED COLD FRONT...BRISK NNE WINDS...AND A THREAT OF MVFR CEILINGS AT EASTERN TERMINALS...ARE EXPECTED ON SUNDAY. WHILE FORECAST CONFIDENCE IS BELOW AVERAGE...THE DEVELOPMENT OF A COASTAL STORM NEAR THE SOUTH AND MIDDLE ATLANTIC COAST MAY RESULT IN A REDEVELOPMENT/SOUTHWESTWARD EXPANSION OF MVFR CEILINGS...AND POSSIBLY RAIN...LATE SUN NIGHT-MON NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...BLS AVIATION...MWS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
634 AM EST SAT DEC 6 2014 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE CAROLINAS BRINGING SHOWERS TODAY AND ISOLATED THUNDERSTORMS TONIGHT...BEFORE MOVING OFFSHORE INTO VERY EARLY SUNDAY. STRONG HIGH PRESSURE WILL BUILD SOUTH SUNDAY AND MONDAY...BRINGING GUSTY NORTH WINDS AND COLDER TEMPERATURES. CANADIAN HIGH PRESSURE NEXT WEEK WILL MAINTAIN SEASONABLY COOL TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 634 AM SATURDAY...OCEAN CONVECTION ON ITS WAY OUT AND NNE OF THE AREA BUT LIGHTER RAINFALL KNOCKING ON OUR FAR INTERIOR DOOR STEP. SMALL ADJUSTMENTS TO POPS TO MATCH RADAR FOR THE DAYBREAK UPDATE AND EARLY MORNING HOURLY TEMPERATURE TRENDS WERE TWEAKED TO REFLECT RECENT METARS...THE PREVIOUS DISCUSSION FOLLOWS WITH NO MAJOR CHANGES TO THE FORECAST TO KICK-OFF SATURDAY. SURFACE LOW PRECEDING AN UPPER TROUGH WAS APPROACHING THE CENTRAL APPALACHIANS...HELPING TO LIFT A COASTAL TROUGH ONTO THE CAROLINA COAST EARLY THIS MORNING. KLTX SENSING MODERATE CONVECTION OFFSHORE OF CAPE FEAR MOVING NORTH TOWARD SURF CITY TO CARTERET COUNTY TO CAPE LOOKOUT. ORGANIZED PRECIPITATION WAS ADVANCING INTO THE WESTERN CAROLINAS. THE TRENDING WEATHER FEATURES OCEAN CONVECTION MOVING N AND NE OF NE SC/SE NC THROUGH MORNING WHILE A BROADER SHIELD OF -RA ENCROACHES FROM THE WEST. A COLD FRONT WILL SWEEP OFF THE COAST LATE THIS EVENING. AHEAD OF THE FRONT DESTABILIZATION MAY STRENGTHEN IN THE AFTERNOON IF CLOUD BREAKS ALLOW SURFACE WARMING...OTHERWISE BEST MIXED LAYER CAPES SPIKE AS DOES OMEGA AND COLUMN MOISTURE OVER THE AREA BETWEEN 00Z-04Z. LOW-LEVEL WINDS DO NOT APPEAR TO SUPPORT A SEVERE THREAT AHEAD OF THE FRONT BUT WILL MAINTAIN ISOLATED TSTM MENTION. MAXIMUM TEMPERATURES WILL NOT BE EASY SINCE BREAKS IN THE CLOUDS COULD WARM LOCAL TEMPS QUICKLY IN THE GROWING WARM SECTOR. BREAKS HOWEVER SHOULD NOT LAST LONG WITH PLENTIFUL UPSTREAM CLOUDS NOTED CURRENTLY...UPPER 60S TO LOWER 70S MOST PLACES AND A LITTLE COOLER BY THE SEA. COLD AIR ADVECTION ALREADY UNDERWAY PRIOR TO DAYBREAK IN BRISK AND DEEP NORTH WIND FLOW...AND GUSTY. MINIMUMS BY FIRST LIGHT SUNDAY IN THE 40S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...STRONG HIGH PRESSURE WILL BUILD DOWN ACROSS THE CAROLINAS ON SUNDAY. A 1045 MB HIGH WILL MOVE ACROSS CANADA FROM JUST NORTH OF THE GREAT LAKES TO THE CANADIAN MARITIMES BY MONDAY. TIGHTENED GRADIENT FLOW WILL EXIST BETWEEN THIS AREA OF HIGH PRESSURE AND LOW PRESSURE LINGERING OVER THE DISTANT OFF SHORE WATERS OF THE CAROLINAS. EXPECT GUSTY NORTHERLY WINDS WINDS THROUGH MUCH OF THE PERIOD. SHOULD SEE SOME CLEARING OUT ON SUNDAY IN DRY NORTHERLY FLOW ESPECIALLY THROUGH INLAND AREAS ALTHOUGH STRONG INVERSION COULD LOCK IN A DECENT LAYER OF MOISTURE UNDERNEATH. CAA WILL BRING 850 TEMPS DOWN SEVERAL DEGREES THROUGH SUNDAY INTO EARLY MONDAY. COASTAL AREAS MAY BE THE LAST PLACE TO SEE SOME SUNSHINE ON SUNDAY AFTN. PCP WATER VALUES DROP DOWN NEAR A QUARTER OF AN INCH INLAND WEST OF I95 BUT CLOSE TO THE COAST VALUES REMAIN AROUND A HALF INCH UNTIL LATER ON SUNDAY. OVERALL EXPECT TO SEE SOME SUNSHINE BY SUNDAY AFTERNOON WITH TEMPS IN THE 50S. MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES ON MONDAY PUSHING NEXT NORTHERN STREAM SYSTEM EAST. THIS WILL PUSH THE HIGH PRESSURE OFF THE COAST OF THE CANADIAN MARITIMES LEAVING A WEDGE OF HIGH PRESSURE DOWN THROUGH THE INLAND CAROLINAS. AT THE SAME TIME LOW PRESSURE OFF SHORE WILL RETROGRADE BACK WEST TOWARD THE CAROLINA COAST BEFORE LIFTING OFF TO THE NORTH MON NIGHT. THE LOW LEVEL INVERSION WILL STRENGTHEN FURTHER AS WARMER AND MOISTER FLOW DEVELOPS IN THE LOW LEVELS. EXPECT LOW CLOUDS AND CONTINUED COOL CONDITIONS WITH GUSTY NORTHERLY WINDS AND TEMPS IN THE 50S ONCE AGAIN. MOST PCP SHOULD REMAIN OFF THE COAST BUT MAY SEE SOME WORK ITS WAY INLAND THROUGH THE DAY AS LOW MOVES UP ALONG THE CAROLINA COAST TOWARD VA. BY MON NIGHT DIGGING MID TO UPPER TROUGH WILL PUSH COLD FRONT EAST WHILE LOW PRESSURE LIFTS OFF TO THE NORTH. THIS WILL SQUEEZE OUT ANY REMAINING WEDGE BY EARLY TUES. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY...DEEP MID TO UPPER TROUGH WILL PUSH NORTHERN STREAM SYSTEM EAST AS LOW PRESSURE SYSTEM LIFTS NORTHEAST AWAY FROM THE CAROLINAS UP ALONG THE EASTERN SEABOARD. ONCE THIS SYSTEM SHIFTS OFF SHORE BY LATE TUES IT WILL DRY OUT THE COLUMN IN DEEP NW FLOW. ALL THE RESIDUAL LOW LEVEL MOISTURE WILL DIMINISH WITH DEEP DRY COLUMN IN PLACE BY WED THROUGH FRI. OVERALL EXPECT CLEARING SKIES ON TUES WITH STRONG DRY HIGH PRESSURE BUILDING IN. A REINFORCING SHOT OF COLD AIR WITH 850 TEMPS DROPPING DOWN BELOW 0C WILL KEEP COOL TEMPS THROUGH MID WEEK. EXPECT HIGHS IN THE 50S MOST DAYS WITH WED BEING THE COOLEST DAY. SHOULD SEE PLENTY OF SUNSHINE WED AND THURS. HIGH PRESSURE WILL MOVE CLOSER OVERHEAD BY THURS INTO FRI WITH WEAK GRADIENT MAINTAINING LIGHT WINDS ALLOWING AIR MASS TO MODIFY AND BECOME SLIGHTLY WARMER. A SHORTWAVE IN THE MID LEVELS WILL PASS THROUGH THURS NIGHT INTO FRI WHICH SHOULD GIVE US SOME PASSING HIGHER CLOUDS. WILL KEEP POPS OUT OF FORECAST FOR NOW. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RATHER LOW CONFIDENCE ON THE BACK END OF THE FORECAST PERIOD WITH RESPECT TO CEILINGS AND THE TIMING OF PRECIP. LOOKS LIKE THERE COULD BE TWO BATCHES OF RAIN/SHOWERS: THE FIRST AROUND SUNRISE WITH A COASTAL TROUGH...THEN ANOTHER ROUND IN THE LATE AFTERNOON AHEAD OF A COLD FRONT. MODELS ARE IN REASONABLE AGREEMENT INTRODUCING IFR STRATUS/FOG AROUND DAYBREAK IF NOT BEFORE...AND THIS MAKES SENSE GIVEN THE WEAK WARM AIR ADVECTION. THE HRRR MODEL THINKS THAT ILM STANDS THE BEST CHANCE FOR MORNING PRECIP...BUT THE MYRTLES COULD ALSO GET INTO THE ACT. THINK THE MORNING PRECIP WILL GIVE WAY TO MVFR CEILINGS AND SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT WHICH WILL ARRIVE AT THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...PERIODS OF MVFR/IFR CIGS ARE LIKELY THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. GUSTY NORTH WINDS SUN/MON BEHIND THE COLD FRONT. BECOMING VFR DURING TUE. VFR WED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 634 AM SATURDAY...WINDS AHEAD OF A COLD FRONT WILL REMAIN RELATIVELY LIGHT TODAY...INCREASING MORE SHARPLY INTO EARLY SUNDAY AS COLD AIR SPILLS ACROSS THE WATERS. ADVISORY SC WATERS AND GALE WATCH NC TO BEGINS 11Z SUNDAY WITH THIS ISSUANCE. PRESENTLY NNE WIND 10 KT AT MASONBORO BUOY AND SE 15G17KT FRYING PAN ILLUSTRATES WELL THE COASTAL TROUGH BOUNDARY. WILL HAVE TO WATCH FOR ADVISORY CONDITIONS EARLIER THAN PLANNED SINCE 41013 ALREADY APPROACHING 6 FT. ISOLATED TSTMS POSSIBLE TONIGHT ON THE 0-20 NM WATERS JUST AHEAD OF THE COLD FRONT. BY DAYBREAK SUNDAY EXPECT 30 KT GUSTS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...GALE WATCH REMAINS IN EFFECT FOR THE NC WATERS BEGINNING SUNDAY MORNING WITH A SMALL CRAFT ADVISORY OVER SOUTH CAROLINA WATERS AS WINDS INCREASE THROUGH SUN INTO SUN NIGHT 20 TO 30 KTS WITH FREQUENT GUSTS TO 35 KTS OR GREATER AS STRONG HIGH PRESSURE BUILDS DOWN INTO THE CAROLINAS. THIS TIGHTENED GRADIENT FLOW WILL CONTINUE INTO MONDAY AS WEDGE STRENGTHENS DOWN THROUGH INLAND CAROLINAS WHILE LOW PRESSURE LINGERS AND SHIFTS CLOSER TO THE COAST BEFORE LIFTING OFF TO THE NORTH BY EARLY TUES. THIS WILL MAINTAIN STRONG NORTHERLY WINDS AND HIGH SEAS. SEAS WILL RAMP UP SUN MORNING ABOVE SCA THRESHOLDS AND PEAKING CLOSE TO 10 FT IN OUTER WATERS OVERNIGHT SUN INTO EARLY MON MORNING. OVERALL SEAS WILL INCREASE UP TO 6 TO 10 FT SUN NIGHT SUBSIDING THROUGH MON NIGHT AS WINDS BEGIN TO DIMINISH DOWN TO 10 TO 20 KTS. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY...HIGH PRESSURE WILL BUILD DOWN FROM THE NORTHWEST THROUGH MID WEEK. THE WINDS WILL DIMINISH THROUGH TUES INTO WED BUT DECENT COLD SURGE COULD KICK WINDS BACK UP TUES NIGHT TO 15 TO 20 KTS AND OUTER SEAS NEAR 6 FT. OTHERWISE EXPECT WINDS TO DROP DOWN TO 10 TO 15 KTS THROUGH THE PERIOD WITH SEAS CLOSER TO SCA TUES BUT DROPPING DOWN THROUGH WED TO 2 TO 5 FT. && .TIDES/COASTAL FLOODING... AS OF 700 PM WEDNESDAY...THE FULL MOON IS TODAY. WE EXPECT ELEVATED WATER LEVELS DURING THE TIME OF HIGH TIDE THROUGH THE WEEKEND. THE MORNING HIGH TIDE WILL BE HIGHEST AND THIS IS WHEN WE EXPECT THE TIDE TO COME UP WELL ONTO THE BEACH. STRONG NNE WINDS SUNDAY AND SUNDAY NIGHT WILL HELP TO ENHANCE THE ASTRONOMICAL EFFECTS. THE LOWER CAPE FEAR RIVER WILL ALSO EXPERIENCE HIGHER THAN PREDICTED WATER LEVELS AND MAY REACH COASTAL FLOOD ADVISORY CRITERIA DURING THE MORNING HIGH TIDE THROUGH THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM EST MONDAY FOR AMZ254-256. GALE WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR AMZ250-252. && $$ NEAR TERM...MJC SHORT TERM...RGZ LONG TERM...RGZ AVIATION...MJC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
951 AM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 950 AM CST SAT DEC 6 2014 CLOUDS CONTINUE TO SPREAD ACROSS THE CWA AS SEEN ON SATELLITE AND WEB CAMS...SO INCREASED CLOUD COVER FOR MUCH OF THE DAY. WE COULD START SEEING SOME BREAKS IN THE WEST LATE AS THE EDGE OF THE CLOUD DECK APPROACHES. THERE HAS BEEN A FEW FLURRIES REPORTED NEAR THE WESTERN CWA BORDER SO INCLUDED AN ISOLATED MENTION THROUGH THE NEXT FEW HOURS. LOWERED HIGHS A DEGREE OR SO WITH INCREASED CLOUDS...BUT STILL THINK WE SHOULD GET INTO THE 20S. UPDATE ISSUED AT 655 AM CST SAT DEC 6 2014 THERE HAS BEEN PATCHY DENSE FOG DEVELOP OVER THE PAST FEW HOURS...BUT QUICKLY DISSIPATE ONCE MID-HIGH CLOUDS COME OVERHEAD. THE ONLY UPDATE IS FOR THE SKY GRID TO ACCOUNT FOR MID-LEVEL CLOUDS SPREADING OVER THE REGION A BIT FASTER THAN ANTICIPATED (FOLLOWED THE RAP 700MB RH FIELD). && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 FREEZING RAIN POTENTIAL ON SUNDAY WILL BE THE MAIN CONCERN FOR THIS PERIOD. 00Z MODELS IN DECENT AGREEMENT...ALTHOUGH DIFFERENCES IN THERMAL PROFILES WILL MAKE FOR A CHALLENGING FORECAST. HIGH PRESSURE PROPAGATES ACROSS THE REGION TODAY WITH SOUTHERLY RETURN FLOW SETTING UP THIS AFTERNOON. SATELLITE IMAGERY AND OBSERVATIONS INDICATE PATCHY FOG DEVELOPING...AND WILL NEED TO MONITOR (DID INCLUDE PATCHY FOG IN THE FORECAST FOR SOME LOCATIONS). WEAK SYSTEM WILL BE PROPAGATING ACROSS SOUTHERN CANADA TODAY...AND ALTHOUGH THE STRONGEST FORCING WILL BE NORTH OF THE INTERNATIONAL BORDER...DO EXPECT AN AREA OF CLOUDS TO MOVE THROUGH THE REGION. THE TEMPERATURE FORECAST IS A BIT TRICKY. MOST AREAS SHOULD BE ABLE TO RISE INTO THE 20S THIS AFTERNOON...THEN AFTER A BRIEF DIP IN VALUES...STRONGER WARM AIR ADVECTION COMMENCES TONIGHT AND ANTICIPATE SLOWLY RISING VALUES. MAJORITY OF MODEL GUIDANCE IS INDICATING A STRONGER SIGNAL FOR FREEZING RAIN SUNDAY MORNING...ESPECIALLY THE SOUTHERN VALLEY INTO WEST CENTRAL MINNESOTA AND PORTIONS OF NORTHWEST MINNESOTA (MAINLY ALONG AND EAST OF A LINE FROM WAHPETON TO BAUDETTE). QPF AMOUNTS LIKELY AROUND 0.10 INCHES. THE GENERAL IDEA IS THAT EVAPORATIVE COOLING WILL TRANSITION A FREEZING RAIN/SLEET MIX TO SNOW...BUT GIVEN THE SREF P-TYPE PROBABILITIES (VERY HIGH FREEZING RAIN PROBABILITIES)...THE THOUGHT IS THAT THE OPERATIONAL MODELS MAY BE EVAPORATIVELY COOLING TOO QUICKLY (WHICH DOES HAPPEN) AND/OR TOO DRY ALOFT. IF CONFIDENCE INCREASES IN THE EXPECTED THERMAL PROFILE...ALONG WITH SFC TEMPERATURES REMAINING BELOW FREEZING...SOME SORT OF ADVISORY MAY BE NEEDED FOR THIS AREA. OTHERWISE...AREAS TO THE WEST WILL LIKELY BE WELL INTO THE 30S ON SUNDAY AND MOSTLY DRY. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 SUNDAY NIGHT-MONDAY NIGHT...DEFORMATION ZONE SNOW SHOWERS SUNDAY NIGHT INTO THE EARLY PORTIONS OF MONDAY AS THE SYSTEM FROM THE SHORT TERM PERIOD MOVES AWAY FROM THE REGION. HIGH PRESSURE BUILDS INTO THE REGION BY LATER MONDAY. ANTICIPATE A COLDER AIRMASS WITH TEMPERATURES NEAR NORMAL (THE HIGHS ON MONDAY MAY OCCUR IN THE MORNING). TUESDAY-FRIDAY...EXTENDED PERIOD BEGINS UNDER NORTHWEST FLOW AND NEAR AVERAGE TEMPERATURES FOR THE FIRST HALF OF DECEMBER. AFTERWARDS GUIDANCE DIFFERS ON TIMING AND PLACEMENT OF SHORT WAVE ENERGY RIDING THROUGH UPPER RIDGE DURING THE MIDDLE OF THE WEEK. ECMWF PREFERS TO KEEP WAVE OVER SOUTHERN CANADA WHILE GFS IS FARTHER SOUTH CLOSER TO THE NORTHERN/CENTRAL PLAINS INTERFACE. GFS IS TYPICALLY A BIT FASTER WITH THIS FEATURE AND THE WEAK SHORT WAVE IS NOT EXPECTED TO HAVE A GREAT IMPACT ON FORECAST. THE EARLY PERIOD AVERAGE TEMPERATURES WILL BEGIN TO WARM FROM WEDNESDAY THROUGH FRIDAY AS RETURN FLOW/WARM ADVECTION INCREASES WITH A SHORT WAVE RIDGE BUILDING INTO THE FORECAST AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 655 AM CST SAT DEC 6 2014 AREA OF VFR CIGS WILL MOVE ACROSS THE REGION TODAY. LIGHT AND VARIABLE WINDS WILL BECOME SOUTHERLY THIS AFTERNOON AND COULD BE A BIT BREEZY THIS EVENING AND OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...TG LONG TERM...WJB/TG AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
655 AM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 655 AM CST SAT DEC 6 2014 THERE HAS BEEN PATCHY DENSE FOG DEVELOP OVER THE PAST FEW HOURS...BUT QUICKLY DISSIPATE ONCE MID-HIGH CLOUDS COME OVERHEAD. THE ONLY UPDATE IS FOR THE SKY GRID TO ACCOUNT FOR MID-LEVEL CLOUDS SPREADING OVER THE REGION A BIT FASTER THAN ANTICIPATED (FOLLOWED THE RAP 700MB RH FIELD). && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 FREEZING RAIN POTENTIAL ON SUNDAY WILL BE THE MAIN CONCERN FOR THIS PERIOD. 00Z MODELS IN DECENT AGREEMENT...ALTHOUGH DIFFERENCES IN THERMAL PROFILES WILL MAKE FOR A CHALLENGING FORECAST. HIGH PRESSURE PROPAGATES ACROSS THE REGION TODAY WITH SOUTHERLY RETURN FLOW SETTING UP THIS AFTERNOON. SATELLITE IMAGERY AND OBSERVATIONS INDICATE PATCHY FOG DEVELOPING...AND WILL NEED TO MONITOR (DID INCLUDE PATCHY FOG IN THE FORECAST FOR SOME LOCATIONS). WEAK SYSTEM WILL BE PROPAGATING ACROSS SOUTHERN CANADA TODAY...AND ALTHOUGH THE STRONGEST FORCING WILL BE NORTH OF THE INTERNATIONAL BORDER...DO EXPECT AN AREA OF CLOUDS TO MOVE THROUGH THE REGION. THE TEMPERATURE FORECAST IS A BIT TRICKY. MOST AREAS SHOULD BE ABLE TO RISE INTO THE 20S THIS AFTERNOON...THEN AFTER A BRIEF DIP IN VALUES...STRONGER WARM AIR ADVECTION COMMENCES TONIGHT AND ANTICIPATE SLOWLY RISING VALUES. MAJORITY OF MODEL GUIDANCE IS INDICATING A STRONGER SIGNAL FOR FREEZING RAIN SUNDAY MORNING...ESPECIALLY THE SOUTHERN VALLEY INTO WEST CENTRAL MINNESOTA AND PORTIONS OF NORTHWEST MINNESOTA (MAINLY ALONG AND EAST OF A LINE FROM WAHPETON TO BAUDETTE). QPF AMOUNTS LIKELY AROUND 0.10 INCHES. THE GENERAL IDEA IS THAT EVAPORATIVE COOLING WILL TRANSITION A FREEZING RAIN/SLEET MIX TO SNOW...BUT GIVEN THE SREF P-TYPE PROBABILITIES (VERY HIGH FREEZING RAIN PROBABILITIES)...THE THOUGHT IS THAT THE OPERATIONAL MODELS MAY BE EVAPORATIVELY COOLING TOO QUICKLY (WHICH DOES HAPPEN) AND/OR TOO DRY ALOFT. IF CONFIDENCE INCREASES IN THE EXPECTED THERMAL PROFILE...ALONG WITH SFC TEMPERATURES REMAINING BELOW FREEZING...SOME SORT OF ADVISORY MAY BE NEEDED FOR THIS AREA. OTHERWISE...AREAS TO THE WEST WILL LIKELY BE WELL INTO THE 30S ON SUNDAY AND MOSTLY DRY. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 SUNDAY NIGHT-MONDAY NIGHT...DEFORMATION ZONE SNOW SHOWERS SUNDAY NIGHT INTO THE EARLY PORTIONS OF MONDAY AS THE SYSTEM FROM THE SHORT TERM PERIOD MOVES AWAY FROM THE REGION. HIGH PRESSURE BUILDS INTO THE REGION BY LATER MONDAY. ANTICIPATE A COLDER AIRMASS WITH TEMPERATURES NEAR NORMAL (THE HIGHS ON MONDAY MAY OCCUR IN THE MORNING). TUESDAY-FRIDAY...EXTENDED PERIOD BEGINS UNDER NORTHWEST FLOW AND NEAR AVERAGE TEMPERATURES FOR THE FIRST HALF OF DECEMBER. AFTERWARDS GUIDANCE DIFFERS ON TIMING AND PLACEMENT OF SHORT WAVE ENERGY RIDING THROUGH UPPER RIDGE DURING THE MIDDLE OF THE WEEK. ECMWF PREFERS TO KEEP WAVE OVER SOUTHERN CANADA WHILE GFS IS FARTHER SOUTH CLOSER TO THE NORTHERN/CENTRAL PLAINS INTERFACE. GFS IS TYPICALLY A BIT FASTER WITH THIS FEATURE AND THE WEAK SHORT WAVE IS NOT EXPECTED TO HAVE A GREAT IMPACT ON FORECAST. THE EARLY PERIOD AVERAGE TEMPERATURES WILL BEGIN TO WARM FROM WEDNESDAY THROUGH FRIDAY AS RETURN FLOW/WARM ADVECTION INCREASES WITH A SHORT WAVE RIDGE BUILDING INTO THE FORECAST AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 655 AM CST SAT DEC 6 2014 AREA OF VFR CIGS WILL MOVE ACROSS THE REGION TODAY. LIGHT AND VARIABLE WINDS WILL BECOME SOUTHERLY THIS AFTERNOON AND COULD BE A BIT BREEZY THIS EVENING AND OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...TG LONG TERM...WJB/TG AVIATION...TG
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1157 AM MST SAT DEC 6 2014 .UPDATE... ISSUED AT 1149 AM MST SAT DEC 6 2014 LOTS OF MID/HIGH CLOUDINESS SPREADING ACROSS SOUTHERN CO AHEAD OF THE NEXT UPPER TROF MOVING INTO THE SOUTHWEST US. THIS HAS RESULTED IN A SLOW WARM UP FOR PORTIONS OF THE LOWER ARKANSAS RIVER VALLEY...KPUB TO KLHX...WHERE TEMPERATURES HAVE HELD IN THE UPPER 30S. HAVE DROPPED MAX TEMPERATURE FOR TODAY A DEGREE OR TWO FOR KPUB AND KLHX...AS WINDS SHOULD STAY LIGHT LIMITING MIXING. ELSEWHERE...SOUTHERLY WINDS ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE PLAINS SHOULD HELP TEMPERATURES WARM INTO THE LOWER 50S. MEANWHILE...STARTING TO SEE THE FIRST ROUNDS OF SNOW VIA KCPW OBSERVATION. THIS SHOULD BECOME MORE WIDESPREAD THROUGH LATE AFTERNOON AND INTO THE EVENING AS THE UPPER TROF APPROACHES. HAVE DELAYED THE ONSET OF SNOW FOR THE SANGRES BASED ON THE LATEST SOLUTIONS FROM HRRR AND RAP13...OTHERWISE...POP GRIDS LOOK ON TARGET. -KT && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 339 AM MST SAT DEC 6 2014 ...SOME LIGHT SNOW FOR THE MOUNTAINS LATER TODAY... A BROAD EXPANSE OF THICK HIGH CLOUDS IS OVERSPREADING WRN CO THIS MORNING. THIS IS ASSOCIATE WITH A TROUGH THAT IS CROSSING THE W COAST. THIS WEAK SYSTEM WILL MOVE STEADILY THROUGH THE DESERT SW THIS MORNING...THEN PASS THROUGH ERN CO THIS EVE. CLOUD COVER SHOULD STAY WITH US THROUGH THIS AFTERNOON...THEN GRADUALLY CLEAR OVERNIGHT FROM W TO E. CLOUDS AND SLIGHT COOLING ALOFT WILL HOLD MAX TEMPS ABOUT 10 DEGREES BELOW ADIABATIC MAXES...OR AROUND 50 DEGREES FOR THE PLAINS...AND 40S FOR THE HIGH VALLEYS. NOT SEEING MUCH POTENTIAL FOR SNOWFALL WITH THIS SYSTEM GIVEN THE GENERALLY WEAK DYNAMICS AND QUICK PROGRESSION. BEST CHANCE FOR SOME LIGHT ACCUMS WILL BE OVER THE SW MTS...WHICH COULD SEE 2-4 INCHES BY SUN MORNING...MAYBE A BIT HIGHER IN SPOTS. ELSEWHERE ALONG THE CONTDVD...JUST AN INCH OR TWO. ERN RANGES WILL SEE SOME SCT SNOW SHOWERS AND POSSIBLY SOME LIGHT ACCUMS FOR THE HIGHER ELEVATIONS. LOOKS RELATIVELY MILD TONIGHT FOR THE PLAINS WITH TEMPS IN THE UPPER 20S TO AROUND FREEZING. ROSE .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 339 AM MST SAT DEC 6 2014 GENERALLY MILD AND DRY CONDITIONS ARE FORECAST TO PREVAIL ACROSS THE REGION THROUGH THE EXTENDED PERIOD. A FAST MOVING UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING EAST OF THE AREA SUNDAY MORNING WITH HIGH PRESSURE ALOFT BUILDING ACROSS THE REGION BY SUNDAY AFTERNOON. MODELS HANG ON TO A FEW LIGHT SNOW SHOWERS OVER THE MOUNTAINS SUNDAY MORNING...WITH ALL SHOWER ACTIVITY COMING TO AN END BY MID TO LATE MORNING SUNDAY. MIGRANT HIGH PRESSURE WILL MOVE ACROSS THE REGION THROUGH TUESDAY. DRY CONDITIONS WILL PERSIST UNDER THIS HIGH PRESSURE. TEMPERATURES WILL REMAIN MILD ACROSS THE REGION WITH 50S FOR THE PLAINS FOR AFTERNOON HIGHS. A WEAK SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS THE DESERT SOUTHWEST ON WEDNESDAY. ALL MODEL GUIDANCE HAS THIS DISTURBANCE MOVING TOO FAR TO THE SOUTH TO BRING ANY PRECIPITATION TO THE AREA. A WEAK COLD FRONT WILL IMPACT THE PLAINS...WITH A FEW DEGREES OF COOLING EXPECTED WEDNESDAY AFTERNOON. HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE AREA FOR LATE IN THE WEEK AS A TROUGH STRENGTHENS ALONG THE WEST COAST. THE UPPER FLOW ACROSS COLORADO WILL TRANSITION TO SOUTHWESTERLY BY THURSDAY WHICH WILL AID IN AFTERNOON MIXING. EXPECT A NICE WARM UP THURSDAY AND FRIDAY WITH LOWER 60S EXPECTED ACROSS THE PLAINS. THERE ARE SOME MODEL DIFFERENCES FRIDAY INTO SATURDAY...THE GFS IS FASTER IN BRINGING THE UPPER SYSTEM OFF THE WEST COAST AND ACROSS COLORADO. THE GFS DEVELOPS WIDESPREAD PRECIPITATION ACROSS THE CONTINENTAL DIVIDE BY FRIDAY NIGHT...AND SPREADING ACROSS THE AREA ON SATURDAY. THE ECMWF IS ABOUT 24 HOURS SLOWER WITH THIS SYSTEM KEEPING COLORADO DRY THROUGH SATURDAY. THIS SYSTEM WILL NEED TO BE MONITORED...AS IT COULD BRING DECENT SNOWFALL TO THE CONTINENTAL DIVIDE. MOZLEY && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1006 AM MST SAT DEC 6 2014 CIGS WILL LOWER THROUGH THE DAY AS A DISTURBANCE OUT WEST MOVES ACROSS THE REGION. CIGS WILL REMAIN VFR AT KCOS AND KPUB WITH WINDS INCREASING OUT OF THE SOUTH AT AROUND 10 KTS AT KCOS DURING THE AFTERNOON. KPUB WILL SEE LIGHTER WINDS FROM THE EAST. SNOW WILL REMAIN CONFINED TO THE MOUNTAIN AREAS TODAY. KALS MAY SEE A PASSING SHOWER IN THE VICINITY OF THE TERMINAL THIS EVENING...BUT PROBABILITY LOOKS TOO LOW AT THIS POINT TO WARRANT INCLUSION IN THE TAF. MEANWHILE MOUNTAIN AREAS WILL SEE IFR TO LIFR CONDITIONS...PARTICULARLY ALONG THE CONTDVD WHERE SNOW SHOWERS WILL INCREASE THROUGH THE AFTERNOON AND CONTINUE THROUGH TONIGHT. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KT SHORT TERM...ROSE LONG TERM...MOZLEY AVIATION...KT Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 503 PM CST Sat Dec 6 2014 .SHORT TERM...(Tonight) ISSUED AT 308 PM CST SAT DEC 6 2014 Clearing trend has finally started to make some headway southward this afternoon, with the edge of the stratocumulus deck generally along a Macomb to Peoria to Pontiac line at 230 pm. AWIPS timing tool would suggest a position along I-72 in the 530-6 pm time frame, while the HRRR is a bit slower around 8 pm. Additional erosion from the northeast is indicated by the HRRR late evening, although at the same time cirrus clouds will be streaming east from the Plains. Thus, have mainly gone with a partly cloudy sky for tonight`s forecast. North/northeast flow to prevail into tonight, as high pressure currently over Lake Superior settles southeast across the Great Lakes. Temperatures expected to drop into the mid to upper 20s overnight. && .LONG TERM...(Sunday through Saturday) ISSUED AT 308 PM CST SAT DEC 6 2014 High pressure will shift eastward from Illinois Sunday as a clipper system approaches from the WNW. This system will start bringing increasingly thick high clouds through the day Sunday, but the air mass will generally remain quite dry in a layer from around 2000 to 12000 feet. This dry layer will take some time to saturate overnight, which means only a slight chance for precipitation NW of the Illinois River before midnight. These layers will saturate through the night allowing a better chance for precipitation reaching the surface mainly during the morning. Dry air will start to move in aloft during the day Monday as the system shifts east of the area, ending deep enough saturation for precipitation processes to take place. Precipitation type looks to be largely rain for central Illinois given a deep warm layer just off the surface. Still some chance for light freezing rain with temperatures hovering very near the freezing mark at the surface. Farther to the north, the warm layer off the surface is less pronounced, which could allow for snow or a mix of rain and snow to reach the surface.. A high pressure ridge will develop over the plains for much of the week with NW flow and dry conditions for central IL. Temperatures will remain below normal for much of the week as a result. Friday and Saturday may see a substantial warmup as the plains ridge shifts over IL. Only chance for precipitation in the extended forecast at this time appears to be around Friday morning as a few models hint at a weak disturbance meandering through the region at this time. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 500 PM CST SAT DEC 6 2014 MVFR and IFR cigs slowly shifting south early this evening and at the same time, a large area of cirrus clouds was streaking east into our area. A band of moisture/clouds (MVFR) was also seen over northeast Illinois coming off of Lake Michigan and was tracking southwest and may affect BMI and CMI in the 01z to 03z time frame. Short term high resolution models continue to push the low clouds south over the next several hours reaching SPI and DEC by around 02z. These two sites look to be the pivot point with respect to their eventual movement later tonight with models suggesting more of a southwest to west track as high pressure shifts over the central Great Lakes and our flow becomes more northeast to east. Once we do lose the MVFR cigs, it appears we will have to deal with the mid and high level (VFR) cigs late tonight and into Sunday. Surface winds will be northeast to east at 5 to 10 kts tonight with winds becoming east to southeast at 10 to 15 kts on Sunday. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Geelhart LONG TERM...Onton AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
405 PM CST SAT DEC 6 2014 .SHORT TERM... 257 PM CST NORTHEAST FLOW OVER THE REGION AHEAD OF HIGH PRESSURE HAS CONTINUED TO EASE IN DRIER AIR. MID-AFTERNOON VISIBLE SATELLITE IMAGERY REVEALS ONLY SOME DEPARTING STRATUS ACROSS THE FAR SOUTHERN FORECAST AREA...AND SOME REMAINING RIBBONS OF LAKE EFFECT CLOUDS INTO FAR NORTHEAST IL AND NORTHWEST IN. WATER VAPOR IMAGERY CONFIRMS DRIER MID-LEVEL AIR AND SUPPRESSION MOVING OVERHEAD WHICH SHOULD MITIGATE CLOUDS THIS EVENING...OUTSIDE OF A FEW LAKE EFFECT CLOUDS INCHING WESTWARD OVER NORTHERN IL WITHIN THE VEERING FLOW. A LIGHT WIND COMPONENT WILL REMAIN THIS EVENING ALTHOUGH AS THE 1039 MB HIGH PASSES ACROSS WI...THE WINDS WILL LIKELY BECOME LIGHT AND VARIABLE ALLOWING FOR FURTHER TEMPERATURE DROP. DEW POINTS ARE SEVERAL DEGREES ABOVE THIS AT PRESENT...BUT NOT REALLY A PATTERN WHERE WOULD EXPECT FOG...ESPECIALLY ANYTHING OF NOTE. SOUTHEAST WINDS WILL SETTLE IN ON SUNDAY WITH THE DEPARTING HIGH AND LOW PRESSURE MARCHING EASTWARD NEAR THE NORTHERN CONUS BORDER. HIGH CLOUDS LOOK TO GRADUALLY INCREASE/THICKEN DURING THE AFTERNOON. GIVEN HIGHS TODAY REACHED THE UPPER 30S TO LOWER 40S WOULD ENVISION SUNDAY BEING IN THE SAME ARENA IF CLOUDS DO NOT THICKEN EARLIER THAN FORECAST. MTF && .LONG TERM... 315 PM CST LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... OVERALL THE EXTENDED PERIOD WILL CONTINUE TO FEATURE A FAIRLY PROGRESSIVE WEATHER PATTERN...WITH ONLY A QUICK HIT OF SOME COLDER AIR FOR LATE TUESDAY INTO WEDNESDAY. THE MAIN FORECAST CONCERNS DURING THE PERIOD WILL BE THE INCREASING POTENTIAL OF A QUICK HIT OF WINTERY WEATHER LATE SUNDAY NIGHT INTO MONDAY MORNING. WATER VAPOR IMAGERY INDICATES THE NEXT PACIFIC SYSTEM OF INTEREST...NOW SHIFTING ONSHORE ACROSS WASHINGTON STATE. THIS FEATURE...ALONG WITH AN ASSOCIATED AREA OF LOW PRESSURE IS EXPECTED TO TRACK QUICKLY ALONG OR NEAR THE CANADIAN INTERNATIONAL BORDER SUNDAY THROUGH TUESDAY. TYPICALLY THIS TYPE OF TRACK IS NOT GOOD FOR MUCH PRECIPITATION FOR THE AREA...AND OVERALL THIS WILL BE THE CASE. HOWEVER...IT APPEARS THAT QUICK HIT OF WINTRY PRECIPITATION IS LIKELY LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. A PERIOD OF INCREASING ISENTROPIC ASCENT COMBINED WITH SOME DECENT Q-VECTOR CONVERGENCE...ASSOCIATED WITH ADDITIONAL SHORTWAVE ENERGY DIGGING SOUTHEASTWARD TOWARDS THAT AREA LATER SUNDAY NIGHT...SHOULD PROVIDE A SHORT PERIOD OF FORCING SUPPORTIVE OF PRECIPITATION ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. OVERALL...THIS STILL APPEARS TO BE A SMALL EVENT FOR THE AREA. HOWEVER...IT APPEARS THAT A STRENGTHENING BAROCLINIC ZONE ALONG AN OCCLUDED FRONTAL BOUNDARY MAY PROVIDE A SHORT PERIOD OF ENHANCED MESOSCALE FORCING...SUPPORTIVE A SHORT PERIOD OF HEAVIER PRECIPITATION...ESPECIALLY GIVEN THE PRESENCE OF STEEP MID LEVEL LAPSE RATES INTO MONDAY MORNING. THUS...IT APPEARS THAT BAND OF PRECIPITATION...POSSIBLY ONLY LASTING A COUPLE HOURS AT ANY GIVEN LOCATION...IS LIKELY TO MOVE ACROSS THE AREA IN TIME FOR THE MONDAY MORNING RUSH. PRECIP TYPE STILL APPEARS TO BE TRICKY WITH THIS ACTIVITY EARLY MONDAY. ASIDE FOR THE NAM SOLUTION...MOST MODEL DERIVED SOUNDINGS ACROSS NORTHERN ILLINOIS INDICATE MAX LAYER TEMPERATURES OF ONLY +1 TO +1.5 DEGREES CELSIUS...WHICH WOULD SUGGEST ONLY PARTIAL MELTING OF DENDRITES...POSSIBLY RESULTING IN SNOW AND SLEET PRECIP TYPES ACROSS MOST OF FAR NORTHERN ILLINOIS. ALSO...GIVEN THAT THERE COULD BE SOME ENHANCE PRECIP RATES WITH THIS ACTIVITY...AS WELL AS THE FACT THAT EVAPORATIVE COOLING POTENTIAL SUNDAY NIGHT WILL BE HIGH...IT APPEARS PRUDENT TO MENTION MORE OF A SNOW AND SLEET SCENARIO ACROSS FAR NORTHERN ILLINOIS RATHER THAN FREEZING RAIN AT THIS POINT. THEREFORE...I HAVE TRENDED THE FORECAST IN THIS DIRECTION. ACCUMULATIONS ARE ALSO POSSIBLE WITH THIS ACTIVITY. IN FACT...SOME AREAS COULD GET A QUICK INCH OF SNOW...IF IT FALLS PRIMARILY AS SUCH. AT THIS TIME IT APPEARS THE BEST POTENTIAL FOR THIS APPEARS TO BE ROUGHLY ALONG AND NORTH OF I-88 IN NORTHERN ILLINOIS. ALTHOUGH TOTAL AMOUNTS WILL BE LIGHT...THE POSSIBILITY OF A QUICK HALF TO ONE INCH OF SNOW RIGHT AROUND DAYBREAK MONDAY COULD CAUSE PROBLEMS FOR THE MONDAY MORNING COMMUTE. AREAS SOUTH OF INTERSTATE 80 COULD SEE MORE OF MIX BAG OF RAIN...FREEZING RAIN...SLEET AND SNOW GIVEN SLIGHTLY WARMER MID LEVEL TEMPERATURES. SURFACE TEMPERATURES HERE MAY BE HOVERING RIGHT AROUND FREEZING...SO QUESTIONS STILL RESIDE AROUND HOW MUCH OF THIS PRECIP WILL BE FROZEN. ONCE THIS BAND OF HEAVER PRECIP SHIFTS EAST OF THE AREA BY LATE MORNING...IT APPEARS THAT THE MID LEVELS WILL DRY OUT SUBSTANTIALLY...THUS ANY LINGERING PRECIP MONDAY AFTERNOON WOULD LIKELY BE MORE DRIZZLY. THE COLDER SIDE OF THE STORM SYSTEM WILL ARRIVE ACROSS THE REGION BY EARLY MONDAY EVENING...AS WINDS BECOME A BIT GUSTY OUT OF THE WEST NORTHWEST. THIS SHOULD RESULT IN A COLDER DAY ACROSS THE AREA ON TUESDAY. MOST AREAS WILL REMAIN DRY TUESDAY AND TUESDAY NIGHT. HOWEVER...SOME LAKE EFFECT SNOW SHOWERS OR FLURRIES ARE POSSIBLE ACROSS NORTHWESTERN INDIANA DURING THE DAY TUESDAY. THEN AS THE LOWER LEVEL FLOW VEERS MORE NORTHERLY LATE TUESDAY THESE LAKE EFFECT FLURRIES COULD GET INTO NORTHEASTERN ILLINOIS TUESDAY EVENING. OVERALL...THIS DOES NOT APPEAR TO BE MUCH OF A LAKE EFFECT EVENT AS LAKE INDUCED INVERSION HEIGHTS DO NOT APPEAR VERY IMPRESSIVE...AND EVEN APPEAR TO REMAIN BELOW THE DENDRITIC GROWTH ZONE. THE WEATHER THE REST OF THE WEEK APPEARS TO BE FAIRLY QUIT...BUT ON A WARMING TREND. MID LEVEL HEIGHT RISES ARE EXPECTED TO OVERSPREAD MUCH OF THE CENTRAL CONUS LATER IN THE PERIOD IN RESPONSE TO THE PERSISTENT NEGATIVE HEIGHT ANOMALIES ACROSS THE NORTHEASTERN PACIFIC AND GULF OF ALASKA REGION SHIFTING EASTWARD TOWARDS THE WESTERN NORTH AMERICAN COAST. THIS PARTICULARLY PATTERN STILL LOOKS TO BE CONDUCE FOR A PERIOD OF MUCH ABOVE NORMAL TEMPERATURES NEXT FRIDAY AND ESPECIALLY INTO SATURDAY. MODEL GUIDANCE HAS BEEN IN GOOD AGREEMENT IN INDICATING THIS LARGER SCALE EL NINO-LIKE PATTERN EVOLVING...AND GIVEN THAT THIS IS PATTERN KNOWN FOR PRODUCING MILD CONDITIONS LOCALLY...CONFIDENCE IS ABOVE AVERAGE FOR THIS PERIOD TO EXPERIENCE ABOVE AVERAGE TEMPERATURES. AT THIS TIME I HAVE REMAINED A BIT CONSERVATIVE ON TEMPERATURES...ONLY WARMING THEM TO NEAR 50 FOR SATURDAY. THIS COULD BE SEVERAL DEGREES TOO LOW IF THE CURRENT MODEL FORECASTS PAN OUT. MOST GUIDANCE IS INDICATING 925 MB TEMPERATURES ANYWHERE FROM +6 TO +10 DEGREES CELSIUS...WHICH COULD SUPPORT TEMPERATURES INTO THE 50S BY NEXT SATURDAY UNDER A 570+ DM MID LEVEL RIDGE. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * THIN SCT/BKN MVFR DECK 2500-2700 FT ERODING SHORTLY...WITH MDW/GYY LIKELY TO OBSERVE A CIG THROUGH ABOUT 00Z. * NORTH-NORTHEAST WINDS 10-15 KT GUSTING AROUND 20 KT WILL DIMINISH QUICKLY THROUGH EARLY EVENING. WINDS BECOME SOUTHEAST AT OR ABOVE 10 KT SUNDAY FROM MIDDAY ON. RATZER //DISCUSSION...UPDATED 18Z... MVFR CLOUDS BEGINNING TO GO BROKEN OR SCATTER OUT IN PLACES THIS AFTERNOON. EXPECT THAT CLOUDS WILL CONTINUE TO SPREAD ONSHORE FROM THE LAKE THROUGH THE AFTERNOON AND EARLY EVENING HOURS. WITH THE CLOUDS BREAKING UP SOME...WINDS WILL CONTINUE TO BE GUSTY OUT OF THE NE. HIGH PRESSURE SLIDES BY TONIGHT WHICH WILL ALLOW SKIES TO CLEAR QUITE A BIT MORE THIS EVENING AND WINDS WILL DIE DOWN AND BECOME EASTERLY. WITH THE HIGH EAST OF THE AREA SUNDAY...EXPECT WINDS TO SHIFT TO THE SOUTHEAST AND APPROACH OR EXCEED 10 KT SUNDAY AFTERNOON. HIGH CLOUDS WILL BE SPREADING IN THROUGH THE DAY. KMD //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE IN TRENDS OF ALL ELEMENTS. RATZER //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...MAINLY VFR. SLGT CHANCE OF LIGHT SNOW/SLEET AND MVFR SUNDAY. E WINDS BECOMING SE. MONDAY...CHANCE RAIN/SLEET/SNOW. MVFR/BRIEF IFR POSSIBLE. S WINDS BECOMING W. TUESDAY...VFR. NW WINDS BECOMING N. WEDNESDAY...VFR. NE WINDS BECOMING ESE. THURSDAY...SLGT CHANCE LIGHT SNOW. VFR. S WINDS. FRIDAY...VFR. SSE WINDS. MDB && .MARINE... 222 PM CST TONIGHT THROUGH SUNDAY THE STIFF NORTHERLY WINDS ACROSS THE LAKE TODAY WILL EASE THIS EVENING AND VEER EASTWARD BY OVERNIGHT. WAVES WILL SUBSIDE BELOW 5 FT BY LATE TONIGHT. THE PROGRESSIVE PATTERN CONTINUES WITH HIGH PRESSURE ADVANCING OVER THE LAKE QUICKLY OVERNIGHT FOLLOWED BY INFLUENCE OF APPROACHING LOW PRESSURE ALREADY BY SUNDAY WITH WINDS TURNING SOUTHEASTERLY. SUNDAY NIGHT ONWARD STRONG HIGH PRESSURE SHIFTING EASTWARD FROM QUEBEC AND WEAK LOW PRESSURE TRACKING EAST ALONG THE CANADIAN BORDER WILL REALLY TIGHTEN THE PRESSURE GRADIENT AND CAUSE SOUTHEAST WINDS TO TURN SOUTH AND STRENGTHEN ON SUNDAY NIGHT INTO MONDAY MORNING. LOOKING AT GUSTS PRIMARILY UP TO 25 TO 30 KT OVER THE OPEN WATERS...BUT COULD SEE A FEW GALE FORCE GUSTS ON NORTH HALF. COLD FRONT TRAILING FROM THE WEAK LOW PRESSURE WILL CROSS THE LAKE MONDAY EVENING AND NIGHT...FOLLOWED BY ANOTHER EXPANSIVE HIGH PRESSURE. WINDS WILL TURN WEST-NORTHWEST MONDAY NIGHT TO NORTHERLY BY TUESDAY MORNING. CURRENTLY EXPECTING SPEEDS/GUSTS UP TO 30 KT LATE MONDAY NIGHT THROUGH TUESDAY...BUT AGAIN CANNOT RULE OUT A PERIOD OF GALES ON THE NORTH TUESDAY MORNING WHEN PRESSURE RISES MAXIMIZE. NORTHERLY WINDS WILL GRADUALLY DIMINISH ON TUESDAY NIGHT INTO WEDNESDAY AS THE HIGH TRAVERSES THE LAKE...SHIFTING TO SOUTHWEST ON THURSDAY INTO THURSDAY NIGHT ON THE BACK SIDE OF THE HIGH. FOR THE NEARSHORE WATERS...SMALL CRAFT ADVISORY CRITERIA IS POSSIBLE SUNDAY NIGHT INTO MONDAY MORNING...ESPECIALLY FOR THE ILLINOIS SHORE. SMALL CRAFT CONDITIONS ARE THEN LIKELY TUESDAY MORNING INTO WEDNESDAY. MTF/RC && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 321 PM CST Sat Dec 6 2014 .SHORT TERM...(Tonight) ISSUED AT 308 PM CST SAT DEC 6 2014 Clearing trend has finally started to make some headway southward this afternoon, with the edge of the stratocumulus deck generally along a Macomb to Peoria to Pontiac line at 230 pm. AWIPS timing tool would suggest a position along I-72 in the 530-6 pm time frame, while the HRRR is a bit slower around 8 pm. Additional erosion from the northeast is indicated by the HRRR late evening, although at the same time cirrus clouds will be streaming east from the Plains. Thus, have mainly gone with a partly cloudy sky for tonight`s forecast. North/northeast flow to prevail into tonight, as high pressure currently over Lake Superior settles southeast across the Great Lakes. Temperatures expected to drop into the mid to upper 20s overnight. && .LONG TERM...(Sunday through Saturday) ISSUED AT 308 PM CST SAT DEC 6 2014 High pressure will shift eastward from Illinois Sunday as a clipper system approaches from the WNW. This system will start bringing increasingly thick high clouds through the day Sunday, but the air mass will generally remain quite dry in a layer from around 2000 to 12000 feet. This dry layer will take some time to saturate overnight, which means only a slight chance for precipitation NW of the Illinois River before midnight. These layers will saturate through the night allowing a better chance for precipitation reaching the surface mainly during the morning. Dry air will start to move in aloft during the day Monday as the system shifts east of the area, ending deep enough saturation for precipitation processes to take place. Precipitation type looks to be largely rain for central Illinois given a deep warm layer just off the surface. Still some chance for light freezing rain with temperatures hovering very near the freezing mark at the surface. Farther to the north, the warm layer off the surface is less pronounced, which could allow for snow or a mix of rain and snow to reach the surface.. A high pressure ridge will develop over the plains for much of the week with NW flow and dry conditions for central IL. Temperatures will remain below normal for much of the week as a result. Friday and Saturday may see a substantial warmup as the plains ridge shifts over IL. Only chance for precipitation in the extended forecast at this time appears to be around Friday morning as a few models hint at a weak disturbance meandering through the region at this time. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 321 PM CST SAT DEC 6 2014 Clearing trend has made more substantial progress than earlier thought, reaching KPIA at 21Z. Have updated the TAFs to scatter out the clouds before 03Z. Some increase in mid and high cloudiness is expected from the west after 06Z. Have kept conditions VFR overnight, but will need to watch for some potential lower visibilities in the areas that never had a chance to really clear out before sunset. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Geelhart LONG TERM...Onton AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
316 PM CST SAT DEC 6 2014 .SHORT TERM... 257 PM CST NORTHEAST FLOW OVER THE REGION AHEAD OF HIGH PRESSURE HAS CONTINUED TO EASE IN DRIER AIR. MID-AFTERNOON VISIBLE SATELLITE IMAGERY REVEALS ONLY SOME DEPARTING STRATUS ACROSS THE FAR SOUTHERN FORECAST AREA...AND SOME REMAINING RIBBONS OF LAKE EFFECT CLOUDS INTO FAR NORTHEAST IL AND NORTHWEST IN. WATER VAPOR IMAGERY CONFIRMS DRIER MID-LEVEL AIR AND SUPPRESSION MOVING OVERHEAD WHICH SHOULD MITIGATE CLOUDS THIS EVENING...OUTSIDE OF A FEW LAKE EFFECT CLOUDS INCHING WESTWARD OVER NORTHERN IL WITHIN THE VEERING FLOW. A LIGHT WIND COMPONENT WILL REMAIN THIS EVENING ALTHOUGH AS THE 1039 MB HIGH PASSES ACROSS WI...THE WINDS WILL LIKELY BECOME LIGHT AND VARIABLE ALLOWING FOR FURTHER TEMPERATURE DROP. DEW POINTS ARE SEVERAL DEGREES ABOVE THIS AT PRESENT...BUT NOT REALLY A PATTERN WHERE WOULD EXPECT FOG...ESPECIALLY ANYTHING OF NOTE. SOUTHEAST WINDS WILL SETTLE IN ON SUNDAY WITH THE DEPARTING HIGH AND LOW PRESSURE MARCHING EASTWARD NEAR THE NORTHERN CONUS BORDER. HIGH CLOUDS LOOK TO GRADUALLY INCREASE/THICKEN DURING THE AFTERNOON. GIVEN HIGHS TODAY REACHED THE UPPER 30S TO LOWER 40S WOULD ENVISION SUNDAY BEING IN THE SAME ARENA IF CLOUDS DO NOT THICKEN EARLIER THAN FORECAST. MTF && .LONG TERM... 315 PM CST LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... OVERALL THE EXTENDED PERIOD WILL CONTINUE TO FEATURE A FAIRLY PROGRESSIVE WEATHER PATTERN...WITH ONLY A QUICK HIT OF SOME COLDER AIR FOR LATE TUESDAY INTO WEDNESDAY. THE MAIN FORECAST CONCERNS DURING THE PERIOD WILL BE THE INCREASING POTENTIAL OF A QUICK HIT OF WINTERY WEATHER LATE SUNDAY NIGHT INTO MONDAY MORNING. WATER VAPOR IMAGERY INDICATES THE NEXT PACIFIC SYSTEM OF INTEREST...NOW SHIFTING ONSHORE ACROSS WASHINGTON STATE. THIS FEATURE...ALONG WITH AN ASSOCIATED AREA OF LOW PRESSURE IS EXPECTED TO TRACK QUICKLY ALONG OR NEAR THE CANADIAN INTERNATIONAL BORDER SUNDAY THROUGH TUESDAY. TYPICALLY THIS TYPE OF TRACK IS NOT GOOD FOR MUCH PRECIPITATION FOR THE AREA...AND OVERALL THIS WILL BE THE CASE. HOWEVER...IT APPEARS THAT QUICK HIT OF WINTRY PRECIPITATION IS LIKELY LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. A PERIOD OF INCREASING ISENTROPIC ASCENT COMBINED WITH SOME DECENT Q-VECTOR CONVERGENCE...ASSOCIATED WITH ADDITIONAL SHORTWAVE ENERGY DIGGING SOUTHEASTWARD TOWARDS THAT AREA LATER SUNDAY NIGHT...SHOULD PROVIDE A SHORT PERIOD OF FORCING SUPPORTIVE OF PRECIPITATION ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. OVERALL...THIS STILL APPEARS TO BE A SMALL EVENT FOR THE AREA. HOWEVER...IT APPEARS THAT A STRENGTHENING BAROCLINIC ZONE ALONG AN OCCLUDED FRONTAL BOUNDARY MAY PROVIDE A SHORT PERIOD OF ENHANCED MESOSCALE FORCING...SUPPORTIVE A SHORT PERIOD OF HEAVIER PRECIPITATION...ESPECIALLY GIVEN THE PRESENCE OF STEEP MID LEVEL LAPSE RATES INTO MONDAY MORNING. THUS...IT APPEARS THAT BAND OF PRECIPITATION...POSSIBLY ONLY LASTING A COUPLE HOURS AT ANY GIVEN LOCATION...IS LIKELY TO MOVE ACROSS THE AREA IN TIME FOR THE MONDAY MORNING RUSH. PRECIP TYPE STILL APPEARS TO BE TRICKY WITH THIS ACTIVITY EARLY MONDAY. ASIDE FOR THE NAM SOLUTION...MOST MODEL DERIVED SOUNDINGS ACROSS NORTHERN ILLINOIS INDICATE MAX LAYER TEMPERATURES OF ONLY +1 TO +1.5 DEGREES CELSIUS...WHICH WOULD SUGGEST ONLY PARTIAL MELTING OF DENDRITES...POSSIBLY RESULTING IN SNOW AND SLEET PRECIP TYPES ACROSS MOST OF FAR NORTHERN ILLINOIS. ALSO...GIVEN THAT THERE COULD BE SOME ENHANCE PRECIP RATES WITH THIS ACTIVITY...AS WELL AS THE FACT THAT EVAPORATIVE COOLING POTENTIAL SUNDAY NIGHT WILL BE HIGH...IT APPEARS PRUDENT TO MENTION MORE OF A SNOW AND SLEET SCENARIO ACROSS FAR NORTHERN ILLINOIS RATHER THAN FREEZING RAIN AT THIS POINT. THEREFORE...I HAVE TRENDED THE FORECAST IN THIS DIRECTION. ACCUMULATIONS ARE ALSO POSSIBLE WITH THIS ACTIVITY. IN FACT...SOME AREAS COULD GET A QUICK INCH OF SNOW...IF IT FALLS PRIMARILY AS SUCH. AT THIS TIME IT APPEARS THE BEST POTENTIAL FOR THIS APPEARS TO BE ROUGHLY ALONG AND NORTH OF I-88 IN NORTHERN ILLINOIS. ALTHOUGH TOTAL AMOUNTS WILL BE LIGHT...THE POSSIBILITY OF A QUICK HALF TO ONE INCH OF SNOW RIGHT AROUND DAYBREAK MONDAY COULD CAUSE PROBLEMS FOR THE MONDAY MORNING COMMUTE. AREAS SOUTH OF INTERSTATE 80 COULD SEE MORE OF MIX BAG OF RAIN...FREEZING RAIN...SLEET AND SNOW GIVEN SLIGHTLY WARMER MID LEVEL TEMPERATURES. SURFACE TEMPERATURES HERE MAY BE HOVERING RIGHT AROUND FREEZING...SO QUESTIONS STILL RESIDE AROUND HOW MUCH OF THIS PRECIP WILL BE FROZEN. ONCE THIS BAND OF HEAVER PRECIP SHIFTS EAST OF THE AREA BY LATE MORNING...IT APPEARS THAT THE MID LEVELS WILL DRY OUT SUBSTANTIALLY...THUS ANY LINGERING PRECIP MONDAY AFTERNOON WOULD LIKELY BE MORE DRIZZLY. THE COLDER SIDE OF THE STORM SYSTEM WILL ARRIVE ACROSS THE REGION BY EARLY MONDAY EVENING...AS WINDS BECOME A BIT GUSTY OUT OF THE WEST NORTHWEST. THIS SHOULD RESULT IN A COLDER DAY ACROSS THE AREA ON TUESDAY. MOST AREAS WILL REMAIN DRY TUESDAY AND TUESDAY NIGHT. HOWEVER...SOME LAKE EFFECT SNOW SHOWERS OR FLURRIES ARE POSSIBLE ACROSS NORTHWESTERN INDIANA DURING THE DAY TUESDAY. THEN AS THE LOWER LEVEL FLOW VEERS MORE NORTHERLY LATE TUESDAY THESE LAKE EFFECT FLURRIES COULD GET INTO NORTHEASTERN ILLINOIS TUESDAY EVENING. OVERALL...THIS DOES NOT APPEAR TO BE MUCH OF A LAKE EFFECT EVENT AS LAKE INDUCED INVERSION HEIGHTS DO NOT APPEAR VERY IMPRESSIVE...AND EVEN APPEAR TO REMAIN BELOW THE DENDRITIC GROWTH ZONE. THE WEATHER THE REST OF THE WEEK APPEARS TO BE FAIRLY QUIT...BUT ON A WARMING TREND. MID LEVEL HEIGHT RISES ARE EXPECTED TO OVERSPREAD MUCH OF THE CENTRAL CONUS LATER IN THE PERIOD IN RESPONSE TO THE PERSISTENT NEGATIVE HEIGHT ANOMALIES ACROSS THE NORTHEASTERN PACIFIC AND GULF OF ALASKA REGION SHIFTING EASTWARD TOWARDS THE WESTERN NORTH AMERICAN COAST. THIS PARTICULARLY PATTERN STILL LOOKS TO BE CONDUCE FOR A PERIOD OF MUCH ABOVE NORMAL TEMPERATURES NEXT FRIDAY AND ESPECIALLY INTO SATURDAY. MODEL GUIDANCE HAS BEEN IN GOOD AGREEMENT IN INDICATING THIS LARGER SCALE EL NINO-LIKE PATTERN EVOLVING...AND GIVEN THAT THIS IS PATTERN KNOWN FOR PRODUCING MILD CONDITIONS LOCALLY...CONFIDENCE IS ABOVE AVERAGE FOR THIS PERIOD TO EXPERIENCE ABOVE AVERAGE TEMPERATURES. AT THIS TIME I HAVE REMAINED A BIT CONSERVATIVE ON TEMPERATURES...ONLY WARMING THEM TO NEAR 50 FOR SATURDAY. THIS COULD BE SEVERAL DEGREES TOO LOW IF THE CURRENT MODEL FORECASTS PAN OUT. MOST GUIDANCE IS INDICATING 925 MB TEMPERATURES ANYWHERE FROM +6 TO +10 DEGREES CELSIUS...WHICH COULD SUPPORT TEMPERATURES INTO THE 50S BY NEXT SATURDAY UNDER A 570+ DM MID LEVEL RIDGE. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * MVFR CIGS SCATTERING SOME TIME LATE THIS AFTERNOON. * N-NNE WINDS 12-15 KT GUSTING TO 20-22 KT AT TIMES THROUGH THE AFTERNOON. SE WINDS AT OR ABOVE 10 KT SUNDAY FROM MIDDAY ON. KMD //DISCUSSION...UPDATED 18Z... MVFR CLOUDS BEGINNING TO GO BROKEN OR SCATTER OUT IN PLACES THIS AFTERNOON. EXPECT THAT CLOUDS WILL CONTINUE TO SPREAD ONSHORE FROM THE LAKE THROUGH THE AFTERNOON AND EARLY EVENING HOURS. WITH THE CLOUDS BREAKING UP SOME...WINDS WILL CONTINUE TO BE GUSTY OUT OF THE NE. HIGH PRESSURE SLIDES BY TONIGHT WHICH WILL ALLOW SKIES TO CLEAR QUITE A BIT MORE THIS EVENING AND WINDS WILL DIE DOWN AND BECOME EASTERLY. WITH THE HIGH EAST OF THE AREA SUNDAY...EXPECT WINDS TO SHIFT TO THE SOUTHEAST AND APPROACH OR EXCEED 10 KT SUNDAY AFTERNOON. HIGH CLOUDS WILL BE SPREADING IN THROUGH THE DAY. KMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * LOW CONFIDENCE IN TIMING OF SCATTERING THE MVFR CLOUD DECK LATER TODAY. * HIGH CONFIDENCE IN WIND TRENDS. KMD //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...MAINLY VFR. SLGT CHANCE OF LIGHT SNOW/SLEET AND MVFR SUNDAY. E WINDS BECOMING SE. MONDAY...CHANCE RAIN/SLEET/SNOW. MVFR/BRIEF IFR POSSIBLE. S WINDS BECOMING W. TUESDAY...VFR. NW WINDS BECOMING N. WEDNESDAY...VFR. NE WINDS BECOMING ESE. THURSDAY...SLGT CHANCE LIGHT SNOW. VFR. S WINDS. FRIDAY...VFR. SSE WINDS. MDB && .MARINE... 222 PM CST TONIGHT THROUGH SUNDAY THE STIFF NORTHERLY WINDS ACROSS THE LAKE TODAY WILL EASE THIS EVENING AND VEER EASTWARD BY OVERNIGHT. WAVES WILL SUBSIDE BELOW 5 FT BY LATE TONIGHT. THE PROGRESSIVE PATTERN CONTINUES WITH HIGH PRESSURE ADVANCING OVER THE LAKE QUICKLY OVERNIGHT FOLLOWED BY INFLUENCE OF APPROACHING LOW PRESSURE ALREADY BY SUNDAY WITH WINDS TURNING SOUTHEASTERLY. SUNDAY NIGHT ONWARD STRONG HIGH PRESSURE SHIFTING EASTWARD FROM QUEBEC AND WEAK LOW PRESSURE TRACKING EAST ALONG THE CANADIAN BORDER WILL REALLY TIGHTEN THE PRESSURE GRADIENT AND CAUSE SOUTHEAST WINDS TO TURN SOUTH AND STRENGTHEN ON SUNDAY NIGHT INTO MONDAY MORNING. LOOKING AT GUSTS PRIMARILY UP TO 25 TO 30 KT OVER THE OPEN WATERS...BUT COULD SEE A FEW GALE FORCE GUSTS ON NORTH HALF. COLD FRONT TRAILING FROM THE WEAK LOW PRESSURE WILL CROSS THE LAKE MONDAY EVENING AND NIGHT...FOLLOWED BY ANOTHER EXPANSIVE HIGH PRESSURE. WINDS WILL TURN WEST-NORTHWEST MONDAY NIGHT TO NORTHERLY BY TUESDAY MORNING. CURRENTLY EXPECTING SPEEDS/GUSTS UP TO 30 KT LATE MONDAY NIGHT THROUGH TUESDAY...BUT AGAIN CANNOT RULE OUT A PERIOD OF GALES ON THE NORTH TUESDAY MORNING WHEN PRESSURE RISES MAXIMIZE. NORTHERLY WINDS WILL GRADUALLY DIMINISH ON TUESDAY NIGHT INTO WEDNESDAY AS THE HIGH TRAVERSES THE LAKE...SHIFTING TO SOUTHWEST ON THURSDAY INTO THURSDAY NIGHT ON THE BACK SIDE OF THE HIGH. FOR THE NEARSHORE WATERS...SMALL CRAFT ADVISORY CRITERIA IS POSSIBLE SUNDAY NIGHT INTO MONDAY MORNING...ESPECIALLY FOR THE ILLINOIS SHORE. SMALL CRAFT CONDITIONS ARE THEN LIKELY TUESDAY MORNING INTO WEDNESDAY. MTF/RC && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 308 PM CST Sat Dec 6 2014 .SHORT TERM...(Tonight) ISSUED AT 308 PM CST SAT DEC 6 2014 Clearing trend has finally started to make some headway southward this afternoon, with the edge of the stratocumulus deck generally along a Macomb to Peoria to Pontiac line at 230 pm. AWIPS timing tool would suggest a position along I-72 in the 530-6 pm time frame, while the HRRR is a bit slower around 8 pm. Additional erosion from the northeast is indicated by the HRRR late evening, although at the same time cirrus clouds will be streaming east from the Plains. Thus, have mainly gone with a partly cloudy sky for tonight`s forecast. North/northeast flow to prevail into tonight, as high pressure currently over Lake Superior settles southeast across the Great Lakes. Temperatures expected to drop into the mid to upper 20s overnight. && .LONG TERM...(Sunday through Saturday) ISSUED AT 308 PM CST SAT DEC 6 2014 High pressure will shift eastward from Illinois Sunday as a clipper system approaches from the WNW. This system will start bringing increasingly thick high clouds through the day Sunday, but the air mass will generally remain quite dry in a layer from around 2000 to 12000 feet. This dry layer will take some time to saturate overnight, which means only a slight chance for precipitation NW of the Illinois River before midnight. These layers will saturate through the night allowing a better chance for precipitation reaching the surface mainly during the morning. Dry air will start to move in aloft during the day Monday as the system shifts east of the area, ending deep enough saturation for precipitation processes to take place. Precipitation type looks to be largely rain for central Illinois given a deep warm layer just off the surface. Still some chance for light freezing rain with temperatures hovering very near the freezing mark at the surface. Farther to the north, the warm layer off the surface is less pronounced, which could allow for snow or a mix of rain and snow to reach the surface.. A high pressure ridge will develop over the plains for much of the week with NW flow and dry conditions for central IL. Temperatures will remain below normal for much of the week as a result. Friday and Saturday may see a substantial warmup as the plains ridge shifts over IL. Only chance for precipitation in the extended forecast at this time appears to be around Friday morning as a few models hint at a weak disturbance meandering through the region at this time. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) ISSUED AT 1133 AM CST SAT DEC 6 2014 Challenging forecast with the low cloud deck that currently covers the TAF sites. An area of clearing is moving southwest from northern Illinois, and is timed to reach KPIA around 2030Z. However, guidance indicates the remainder of the TAF sites will stay with the lower ceilings through the evening. Ceilings in eastern Illinois and western Indiana currently around 1500 feet, and think that there will be gradual improvement to at least that level this afternoon. HRRR and RAP models suggest any wholesale clearing probably would be after 06Z, as some drier air is advected southwest from lower Michigan. Northerly winds will gradually trend clockwise this evening as high pressure builds into the Great Lakes, then become more east-southeast on Sunday as the high moves away. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Geelhart LONG TERM...Onton AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1238 PM CST SAT DEC 6 2014 .UPDATE...1057 AM CST MINOR ADJUSTMENTS HAVE BEEN MADE TO CLOUD TRENDS AND TEMPERATURES THIS AFTERNOON. BROAD WEAK COLD AIR ADVECTION CONTINUES ACROSS THE FORECAST AREA AS LOW PRESSURE OVER THE CENTRAL APPALACHIANS PULLS AWAY AND HIGH PRESSURE OVER NORTHERN MN BUILDS EASTWARD. SYNOPTIC STRATUS CLOUDS CONTINUE BASICALLY SOUTH OF I-80 WHILE LAKE INDUCED CLOUDS PERSIST ACROSS MOST OF THE CHICAGO METRO AREA. VISIBLE SATELLITE IMAGERY IS INDICATING BREAKS ACROSS THE LAKE AS DRIER AIR FILTERS IN AND GIVEN THE SOMEWHAT WEAK COLD ADVECTION. ACARS DATA INDICATES THE INVERSION IS STILL STOUT BUT WEAKENING AND THE SATURATION IS ONLY ABOUT 1000 FT THICK. WITH THE UPSTREAM SATELLITE TRENDS AND THE SOMEWHAT SHALLOW DEPTH OF THE CLOUDS...THINK MANY AREAS ARE GOING TO GET SOME THINNING OR SCATTERING CLOUD COVER BY MID-AFTERNOON...WITH THE EXCEPTION BEING THE FAR SOUTHERN FORECAST AREA. HAVE ADJUSTED TEMPERATURES AS WELL AS CAN FOR THE FLUCTUATING CLOUD COVER...THOUGH HIGHS FALL OUT SIMILARLY TO FORECAST. MTF && .SHORT TERM... 409 AM CST THROUGH SATURDAY NIGHT... FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...THE MAIN FORECAST CONCERNS WILL FOCUS ON SKY COVER AND THE IMPACT ON TEMPERATURE TRENDS. LATEST SURFACE ANALYSIS AND SATELLITE IMAGERY INDICATE AN EXTENSIVE STRATUS DECK ACROSS THE REGION TRAPPED BENEATH A STRONG INVERSION BASED AT AROUND 900MB. LATEST MODEL SOUNDINGS INDICATE THAT THE INVERSION WILL HOLD FAST THROUGH THE REMAINDER OF THE NIGHT AND MUCH OF THE DAY SATURDAY. ALSO...AS THE CENTER OF HIGH PRESSURE MOVES ACROSS THE UPPER GREAT LAKES AND LOW PRESSURE CONTINUES TO MOVE THROUGH THE OHIO VALLEY...WINDS WILL REMAIN NELY OFF OF LAKE MICHIGAN...KEEPING MUCH OF NERN IL AND NWRN IN UNDER CLOUD COVER A BIT LONGER THAN PREVIOUSLY ANTICIPATED. AS THE CENTER OF THE HIGH SHIFTS TO THE EAST LATE THIS AFTERNOON AND THIS EVENING...SFC FLOW WILL VEER MORE ELY-SELY...ALLOWING THE STRATUS DECK TO FINALLY SCATTER OUT. NWRN PORTIONS OF THE CWA...GENERALLY WEST OF THE FOX VALLEY COULD SCATTER OUT A BIT QUICKER THAN NERN IL/NWRN IN AND LOCATION UNDER A FETCH OFF OF LAKE MICHIGAN. THIS MAKES THE TEMPERATURE FORECAST FOR SATURDAY A BIT TRICKY AND WILL ULTIMATELY DEPEND ON HOW QUICKLY CLOUD COVER CAN BREAK UP. HOWEVER...THE REGION WILL STILL BE UNDER A COLD ADVECTIVE PATTERN AS THE CENTER OF THE HIGH BUILDS ACROSS NRN MN AND LAKE SUPERIOR TODAY...SO THE DIURNAL TEMPERATURE TREND SHOULD BE A LITTLE SLOWER THAN...BUT AS THE CENTER OF THE HIGH SHIFT EAST OF LAKE SUPERIOR LATE THIS AFTERNOON...THERE IS THE POTENTIAL FOR A LITTLE WARM ADVECTION...AND WITH CLEARING SKIES...TEMPERATURES COULD SPIKE A FEW DEGREES LATE THIS AFTERNOON...BEFORE THE SUN ANGLE GETS TOO LOW. FOR THE REMAINDER OF SATURDAY NIGHT...EXPECT QUIET CONDITIONS AS SFC RIDGING EXTENDS SOUTHWEST ACROSS THE AREA AND THROUGH THE MIDDLE MISSISSIPPI VALLEY...WITH WINDS GRADUALLY VEERING TO SELY BY SUNDAY MORNING. WITH DECREASING CLOUD COVER...DECREASING LOW LEVEL MOISTURE...THE LOWER LEVELS SHOULD BE ABLE TO DECOUPLE OVERNIGHT WITH WINDS DROPPING OFF AND RADIATIVE COOLING ALLOWING FOR TEMPERATURES TO DROP INTO THE LOWER 20S FOR MOST AREAS...WITH THE EXCEPTION OF THE URBAN HEAT ISLAND OF THE CHICAGO METRO AREA WHICH SHOULD REMAIN IN THE UPPER 20S TO AROUND 30F. KREIN && .LONG TERM... 409 AM CST SUNDAY THROUGH NEXT FRIDAY... SUNDAY IS SHAPING UP TO BE A RELATIVELY PLEASANT DAY WITH SELY WINDS PERSISTING THROUGH THE DAY AS THE HIGH MOVES INTO SERN CANADA AND A LOW PRESSURE SYSTEM MOVES OUT OF THE SRN CANADIAN ROCKIES AND ACROSS THE NRN PLAINS. THE EVOLUTION OF THIS SYSTEM HAS BEEN RELATIVELY CONSISTENT OVER RECENT MODEL RUNS...IN TRACKING ACROSS THE NORTHERN PLAINS AND DRAGGING A WEAK COLD FRONT AS IT TRACKS EWD. WINDS AHEAD OF THE SYSTEM WILL VEER TO MORE SOUTHERLY ALLOWING SOME WARMER AIR TO FILTER INTO THE REGION...BRINGING HIGHS IN THE UPPER 30S ACROSS THE AREA. THE WEATHER PICTURE BECOMES A LITTLE MORE COMPLICATED AS THE NEXT SYSTEM APPROACHES THE REGION. SINCE HIGH PRESSURE RIDGING IS STILL EXPECTED TO EXTEND FROM NEW ENGLAND THROUGH THE LOWER MISSISSIPPI VALLEY...THE GULF OF MEXICO WILL BE CUT OFF FROM THE APPROACHING SYSTEM AND THE ONLY AVAILABLE MOISTURE FOR IT TO WORK WITH WILL BE THE MEAGER AMOUNTS IN PLACE...PWATS AROUND A QUARTER OF AN INCH AND WHAT MOISTURE IT CAN BRING AS A PACIFIC SOURCED MID LEVEL SHORTWAVE. THROUGH THE EVENING ON SUNDAY...SFC TEMPERATURES ARE EXPECTED TO DROP OFF INTO THE UPPER 20S TO THE LOWER 30S. MODEL SOUNDING FOR SUNDAY NIGHT INTO MONDAY MORNING INDICATE WARMING ABOVE THE BOUNDARY LAYER WITH TEMPS RISING TO 1-2C ABOVE A SUB-FREEZING SFC LAYER. THE PCPN TYPE FORECAST FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE COMPLICATED BY THE DEPTH AND DEGREE OF THE WARM LAYER AND HOW FAR NORTH THE WARM LAYER CAN REACH. THE LATEST GUIDANCE SUGGESTS THAT PCPN SHOULD START OUT AS A LITTLE LIGHT SNOW OVER THE ROCKFORD AREA EARLY SUNDAY EVENING BEFORE THE WARM INTRUSION REACHES INTO NCNTRL IL...WITH A TRANSITION OVER TO FREEZING RAIN AND...PERHAPS...A LITTLE SLEET MIXING IN...WHICH WOULD BE DEPENDENT ON THE DEPTH OF THE SURFACE-BASED FREEZING LAYER. AS THE SYSTEM SLOWLY CROSSES THE AREA...MANY LOCATIONS COULD SEE A PERIOD OF LIGHT FREEZING RAIN LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING...BEFORE CHANGING OVER TO ALL RAIN BY MIDDAY MONDAY. WITH AVAILABLE DEEP LAYER MOISTURE STILL LIMITED...WITH PWATS ONLY OF A HALF INCH OR SO...PCPN AMOUNTS SHOULD BE LIGHT...BUT EVEN A LIGHT GLAZING OF FREEZING RAIN IN TIME FOR THE MONDAY MORNING RUSH HOURS COULD CREATE TRAVEL DIFFICULTIES. HOWEVER...HIGH PRESSURE IS EXPECTED TO QUICKLY BUILD ACROSS THE REGION FOLLOWING THE FRONTAL PASSAGE...AND ANY PCPN SHOULD COME TO AN END BY LATE MONDAY AFTERNOON OVER THE WRN PORTIONS OF THE CWA AND IN THE EARLY EVENING FOR THE FAR SOUTHEAST. TEMPERATURES SHOULD BE HIGH ENOUGH DURG THE LATE AFTERNOON HOURS THAT THE CHANCES FOR ANY FREEZING PCPN FOR THE EVENING RUSH HOURS ARE LOW. AS THE NEXT AREA OF HIGH PRESSURE BUILDS ACROSS THE REGION...A SHORT PERIOD OF COOL...DRY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY...WITH HIGHS IN THE LOWER TO MIDDLE 30S AND OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. THE SYSTEM PASSING THROUGH THE AREA MONDAY NIGHT IS EXPECTED TO DEVELOP INTO A DEEP UPPER LOW OVER THE MID ATLANTIC REGION BY WEDNESDAY AND THEN SLOWLY MOVE UP THE EAST COAST. BY WEDNESDAY NIGHT...THE DEEP UPPER LOW WILL MOVE OVER NEW ENGLAND AS UPPER RIDING BUILDS FROM THE SRN ROCKIES THROUGH THE UPPER MISSISSIPPI VALLEY. A WEAK SHORTWAVE IN THE NLY FLOW ALOFT BETWEEN THESE TO LARGE SCALE SYSTEMS COULD BRING A BIT OF LIGHT SNOW FOR WEDNESDAY NIGHT INTO THURSDAY...BUT ANY ASSOCIATED SNOWFALL SHOULD BE LIGHT. TOWARDS THE END OF THE WEEK..THE UPPER RIDGING IS EXPECTED TO BUILD ACROSS THE UPPER MIDWEST...BRINGING A WARMING TREND FOR LATE NEXT WEEK...WITH TEMPS POSSIBLY REACHING THE LOWER TO MIDDLE 40S BY NEXT FRIDAY. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MVFR CIGS SCATTERING SOME TIME LATE THIS AFTERNOON. * N-NNE WINDS 12-15 KT GUSTING TO 20-22 KT AT TIMES THROUGH THE AFTERNOON. SE WINDS AT OR ABOVE 10 KT SUNDAY FROM MIDDAY ON. KMD //DISCUSSION...UPDATED 18Z... MVFR CLOUDS BEGINNING TO GO BROKEN OR SCATTER OUT IN PLACES THIS AFTERNOON. EXPECT THAT CLOUDS WILL CONTINUE TO SPREAD ONSHORE FROM THE LAKE THROUGH THE AFTERNOON AND EARLY EVENING HOURS. WITH THE CLOUDS BREAKING UP SOME...WINDS WILL CONTINUE TO BE GUSTY OUT OF THE NE. HIGH PRESSURE SLIDES BY TONIGHT WHICH WILL ALLOW SKIES TO CLEAR QUITE A BIT MORE THIS EVENING AND WINDS WILL DIE DOWN AND BECOME EASTERLY. WITH THE HIGH EAST OF THE AREA SUNDAY...EXPECT WINDS TO SHIFT TO THE SOUTHEAST AND APPROACH OR EXCEED 10 KT SUNDAY AFTERNOON. HIGH CLOUDS WILL BE SPREADING IN THROUGH THE DAY. KMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * LOW CONFIDENCE IN TIMING OF SCATTERING THE MVFR CLOUD DECK LATER TODAY. * HIGH CONFIDENCE IN WIND TRENDS. KMD //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...MAINLY VFR. SLGT CHANCE OF LIGHT SNOW/SLEET AND MVFR SUNDAY. E WINDS BECOMING SE. MONDAY...CHANCE RAIN/SLEET/SNOW. MVFR/BRIEF IFR POSSIBLE. S WINDS BECOMING W. TUESDAY...VFR. NW WINDS BECOMING N. WEDNESDAY...VFR. NE WINDS BECOMING ESE. THURSDAY...SLGT CHANCE LIGHT SNOW. VFR. S WINDS. FRIDAY...VFR. SSE WINDS. MDB && .MARINE... 256 AM CST LOW PRESSURE CONTINUES TO MOVE NORTHEAST UP THE OHIO RIVER VALLEY EARLY THIS MORNING WITH STRONG HIGH PRESSURE MOVING EASTWARD ACROSS THE EASTERN DAKOTAS. WINDS ARE STARTING TO INCREASE AS THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS TIGHTENS UP THROUGH THE MORNING. AS A RESULT...EXPECT NORTH TO NORTHEAST WINDS TO RANGE FROM 20 TO 25 KT WITH GUSTS TO 30 KT ACROSS THE CENTRAL AND SOUTHERN PARTS OF THE LAKE THIS MORNING/AFTERNOON WITH NORTHERN AREAS DIMINISHING THROUGH THE AFTERNOON AS THE INFLUENCE OF THE HIGH ARRIVES. SPEEDS WILL DIMINISH ACROSS THE LAKE THIS EVENING AND TONIGHT AS THE DIRECTION TURNS EAST THEN SOUTHEAST AS THE HIGH SHIFTS TO THE EAST. WILL CONTINUE WITH THE SMALL CRAFT ADVISORY INTO EARLY TONIGHT AS THE LONG FETCH OF WIND WILL KEEP WAVES ELEVATED AFTER WINDS DIMINISH THIS EVENING. LOW PRESSURE WILL DEVELOP IN THE LEE OF THE NORTHERN ROCKIES SUNDAY AND MOVE EASTWARD ALONG THE U.S./CANADIAN BORDER...CROSSING LAKE SUPERIOR MONDAY EVENING. THE LOW WILL DRAG A COLD FRONT ACROSS THE LAKE MONDAY EVENING. SOUTHERLY WINDS WILL INCREASE AHEAD OF THE LOW SUNDAY AND SUNDAY NIGHT THEN SHIFT TO THE NORTHWEST BEHIND THE FRONT MONDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD IN BEHIND THE LOW INTO TUESDAY WITH A FAIRLY STRONG PUSH OF COLDER AIR AND A TIGHT PRESSURE GRADIENT SUPPORTING GUSTY NORTH TO NORTHWEST WINDS. WINDS WILL DIMINISH WEDNESDAY AS THE HIGH MOVES OVERHEAD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1133 AM CST Sat Dec 6 2014 .UPDATE... ISSUED AT 939 AM CST SAT DEC 6 2014 Main concern for today is with cloud cover. Widespread stratus covers the forecast area this morning, with ceilings east of I-57 managing to reach just above 1000 feet while they remain 500 feet or less most areas west. This morning`s upper air sounding, plus forecast soundings off the latest NAM and RAP models, show a persistent inversion around 950 mb. There is some clearing that has occurred over the northwest corner of Illinois, but visible satellite loops showing only slow southern progress toward the Quad Cities area. We`re in the time of year where low sun angle makes it difficult to burn off the low clouds. Areas northwest of Peoria most likely to see any sun this afternoon although there will still be quite a few clouds around. The remainder of the CWA should remain mainly cloudy. Going forecast is in pretty good shape, and only required some minor tweaks to incorporate current trends. && .SHORT TERM...(Today) ISSUED AT 323 AM CST SAT DEC 6 2014 The 08z/2am surface analysis has a 1015mb low in NC Kentucky moving northeast along a stationary front. Rain showers on the NW flank of the low are steadily progressing eastward out of our E-SE counties. The back edge of precip should reach I-57 by 09z/3am and be completely out of our IL counties by 13z/7am. Despite dry air aloft flowing into Illinois on N-NW winds, a strong subsidence inversion is indicated in all the short term models. That will limit mixing of the dry air in to the low level moisture, and work to keep clouds across our forecast area over the next 12 hours if not well into tonight. The satellite images are showing a clearing line progressing south toward IL across MN/WI, however, that clearing should slow down with the intensification of the inversion today. High temps will not climb appreciably under the blanket of clouds, with readings topping out in the upper 30s toward Galesburg and into the mid 40s toward Lawrenceville. && .LONG TERM...(Tonight through Friday) ISSUED AT 323 AM CST SAT DEC 6 2014 High pressure continues to build into the region, although the inversion remains and will likely see a continuation of the clouds until the incredibly dry air aloft finally works its way down into the higher RH in the llvls. This same dry air is also the deciding factor in the next issue for the forecast with an approaching wave Sun night/Monday. Prev models had more disagreement and the NAM with a more southerly track for the wave was the outlier. With this run, both the GFS and ECMWF starting to look a lot more like the prev NAM. A small system developing into a larger upper trof late in the weekend...with the look of two smaller waves bringing pops back into the region. Although the GFS and the ECMWF are more consistent with the prev NAM, the NAM is far more scarce with the QPF. Keeping the forecast chances low for shower activity after midnight Sun night/Monday... not only for lack of continuity from run to run, but the considerable amount of dry air will take a while to overcome. Not convinced the best lift will coincide with the eventual saturation of the column. Beyond Monday and its cold front, temps cool briefly, then moderate back into the 40s for highs through the end of the week. 00z ECMWF completely pulls back on a small disturbance Wed night/Thursday, and should this trend continue, will likely pull the pops altogether out of the next couple runs. For now, slight pops in the forecast to cover a brief disturbance diving into the Great Lakes region on the retreating edge of the larger scale 500 mb trof exiting out to the northeast. This difference btwn the GFS and the European also delineates the break point in the extended between any agreement in the midst of a small pattern shift. Depth of the thickness ridge going into day 7 and 8 will definitely result in some blend issues going into next weekend. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) ISSUED AT 1133 AM CST SAT DEC 6 2014 Challenging forecast with the low cloud deck that currently covers the TAF sites. An area of clearing is moving southwest from northern Illinois, and is timed to reach KPIA around 2030Z. However, guidance indicates the remainder of the TAF sites will stay with the lower ceilings through the evening. Ceilings in eastern Illinois and western Indiana currently around 1500 feet, and think that there will be gradual improvement to at least that level this afternoon. HRRR and RAP models suggest any wholesale clearing probably would be after 06Z, as some drier air is advected southwest from lower Michigan. Northerly winds will gradually trend clockwise this evening as high pressure builds into the Great Lakes, then become more east-southeast on Sunday as the high moves away. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...Shimon LONG TERM...HJS AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1025 AM CST SAT DEC 6 2014 .SHORT TERM... 409 AM CST THROUGH SATURDAY NIGHT... FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...THE MAIN FORECAST CONCERNS WILL FOCUS ON SKY COVER AND THE IMPACT ON TEMPERATURE TRENDS. LATEST SURFACE ANALYSIS AND SATELLITE IMAGERY INDICATE AN EXTENSIVE STRATUS DECK ACROSS THE REGION TRAPPED BENEATH A STRONG INVERSION BASED AT AROUND 900MB. LATEST MODEL SOUNDINGS INDICATE THAT THE INVERSION WILL HOLD FAST THROUGH THE REMAINDER OF THE NIGHT AND MUCH OF THE DAY SATURDAY. ALSO...AS THE CENTER OF HIGH PRESSURE MOVES ACROSS THE UPPER GREAT LAKES AND LOW PRESSURE CONTINUES TO MOVE THROUGH THE OHIO VALLEY...WINDS WILL REMAIN NELY OFF OF LAKE MICHIGAN...KEEPING MUCH OF NERN IL AND NWRN IN UNDER CLOUD COVER A BIT LONGER THAN PREVIOUSLY ANTICIPATED. AS THE CENTER OF THE HIGH SHIFTS TO THE EAST LATE THIS AFTERNOON AND THIS EVENING...SFC FLOW WILL VEER MORE ELY-SELY...ALLOWING THE STRATUS DECK TO FINALLY SCATTER OUT. NWRN PORTIONS OF THE CWA...GENERALLY WEST OF THE FOX VALLEY COULD SCATTER OUT A BIT QUICKER THAN NERN IL/NWRN IN AND LOCATION UNDER A FETCH OFF OF LAKE MICHIGAN. THIS MAKES THE TEMPERATURE FORECAST FOR SATURDAY A BIT TRICKY AND WILL ULTIMATELY DEPEND ON HOW QUICKLY CLOUD COVER CAN BREAK UP. HOWEVER...THE REGION WILL STILL BE UNDER A COLD ADVECTIVE PATTERN AS THE CENTER OF THE HIGH BUILDS ACROSS NRN MN AND LAKE SUPERIOR TODAY...SO THE DIURNAL TEMPERATURE TREND SHOULD BE A LITTLE SLOWER THAN...BUT AS THE CENTER OF THE HIGH SHIFT EAST OF LAKE SUPERIOR LATE THIS AFTERNOON...THERE IS THE POTENTIAL FOR A LITTLE WARM ADVECTION...AND WITH CLEARING SKIES...TEMPERATURES COULD SPIKE A FEW DEGREES LATE THIS AFTERNOON...BEFORE THE SUN ANGLE GETS TOO LOW. FOR THE REMAINDER OF SATURDAY NIGHT...EXPECT QUIET CONDITIONS AS SFC RIDGING EXTENDS SOUTHWEST ACROSS THE AREA AND THROUGH THE MIDDLE MISSISSIPPI VALLEY...WITH WINDS GRADUALLY VEERING TO SELY BY SUNDAY MORNING. WITH DECREASING CLOUD COVER...DECREASING LOW LEVEL MOISTURE...THE LOWER LEVELS SHOULD BE ABLE TO DECOUPLE OVERNIGHT WITH WINDS DROPPING OFF AND RADIATIVE COOLING ALLOWING FOR TEMPERATURES TO DROP INTO THE LOWER 20S FOR MOST AREAS...WITH THE EXCEPTION OF THE URBAN HEAT ISLAND OF THE CHICAGO METRO AREA WHICH SHOULD REMAIN IN THE UPPER 20S TO AROUND 30F. KREIN && .LONG TERM... 409 AM CST SUNDAY THROUGH NEXT FRIDAY... SUNDAY IS SHAPING UP TO BE A RELATIVELY PLEASANT DAY WITH SELY WINDS PERSISTING THROUGH THE DAY AS THE HIGH MOVES INTO SERN CANADA AND A LOW PRESSURE SYSTEM MOVES OUT OF THE SRN CANADIAN ROCKIES AND ACROSS THE NRN PLAINS. THE EVOLUTION OF THIS SYSTEM HAS BEEN RELATIVELY CONSISTENT OVER RECENT MODEL RUNS...IN TRACKING ACROSS THE NORTHERN PLAINS AND DRAGGING A WEAK COLD FRONT AS IT TRACKS EWD. WINDS AHEAD OF THE SYSTEM WILL VEER TO MORE SOUTHERLY ALLOWING SOME WARMER AIR TO FILTER INTO THE REGION...BRINGING HIGHS IN THE UPPER 30S ACROSS THE AREA. THE WEATHER PICTURE BECOMES A LITTLE MORE COMPLICATED AS THE NEXT SYSTEM APPROACHES THE REGION. SINCE HIGH PRESSURE RIDGING IS STILL EXPECTED TO EXTEND FROM NEW ENGLAND THROUGH THE LOWER MISSISSIPPI VALLEY...THE GULF OF MEXICO WILL BE CUT OFF FROM THE APPROACHING SYSTEM AND THE ONLY AVAILABLE MOISTURE FOR IT TO WORK WITH WILL BE THE MEAGER AMOUNTS IN PLACE...PWATS AROUND A QUARTER OF AN INCH AND WHAT MOISTURE IT CAN BRING AS A PACIFIC SOURCED MID LEVEL SHORTWAVE. THROUGH THE EVENING ON SUNDAY...SFC TEMPERATURES ARE EXPECTED TO DROP OFF INTO THE UPPER 20S TO THE LOWER 30S. MODEL SOUNDING FOR SUNDAY NIGHT INTO MONDAY MORNING INDICATE WARMING ABOVE THE BOUNDARY LAYER WITH TEMPS RISING TO 1-2C ABOVE A SUB-FREEZING SFC LAYER. THE PCPN TYPE FORECAST FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE COMPLICATED BY THE DEPTH AND DEGREE OF THE WARM LAYER AND HOW FAR NORTH THE WARM LAYER CAN REACH. THE LATEST GUIDANCE SUGGESTS THAT PCPN SHOULD START OUT AS A LITTLE LIGHT SNOW OVER THE ROCKFORD AREA EARLY SUNDAY EVENING BEFORE THE WARM INTRUSION REACHES INTO NCNTRL IL...WITH A TRANSITION OVER TO FREEZING RAIN AND...PERHAPS...A LITTLE SLEET MIXING IN...WHICH WOULD BE DEPENDENT ON THE DEPTH OF THE SURFACE-BASED FREEZING LAYER. AS THE SYSTEM SLOWLY CROSSES THE AREA...MANY LOCATIONS COULD SEE A PERIOD OF LIGHT FREEZING RAIN LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING...BEFORE CHANGING OVER TO ALL RAIN BY MIDDAY MONDAY. WITH AVAILABLE DEEP LAYER MOISTURE STILL LIMITED...WITH PWATS ONLY OF A HALF INCH OR SO...PCPN AMOUNTS SHOULD BE LIGHT...BUT EVEN A LIGHT GLAZING OF FREEZING RAIN IN TIME FOR THE MONDAY MORNING RUSH HOURS COULD CREATE TRAVEL DIFFICULTIES. HOWEVER...HIGH PRESSURE IS EXPECTED TO QUICKLY BUILD ACROSS THE REGION FOLLOWING THE FRONTAL PASSAGE...AND ANY PCPN SHOULD COME TO AN END BY LATE MONDAY AFTERNOON OVER THE WRN PORTIONS OF THE CWA AND IN THE EARLY EVENING FOR THE FAR SOUTHEAST. TEMPERATURES SHOULD BE HIGH ENOUGH DURG THE LATE AFTERNOON HOURS THAT THE CHANCES FOR ANY FREEZING PCPN FOR THE EVENING RUSH HOURS ARE LOW. AS THE NEXT AREA OF HIGH PRESSURE BUILDS ACROSS THE REGION...A SHORT PERIOD OF COOL...DRY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY...WITH HIGHS IN THE LOWER TO MIDDLE 30S AND OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. THE SYSTEM PASSING THROUGH THE AREA MONDAY NIGHT IS EXPECTED TO DEVELOP INTO A DEEP UPPER LOW OVER THE MID ATLANTIC REGION BY WEDNESDAY AND THEN SLOWLY MOVE UP THE EAST COAST. BY WEDNESDAY NIGHT...THE DEEP UPPER LOW WILL MOVE OVER NEW ENGLAND AS UPPER RIDING BUILDS FROM THE SRN ROCKIES THROUGH THE UPPER MISSISSIPPI VALLEY. A WEAK SHORTWAVE IN THE NLY FLOW ALOFT BETWEEN THESE TO LARGE SCALE SYSTEMS COULD BRING A BIT OF LIGHT SNOW FOR WEDNESDAY NIGHT INTO THURSDAY...BUT ANY ASSOCIATED SNOWFALL SHOULD BE LIGHT. TOWARDS THE END OF THE WEEK..THE UPPER RIDGING IS EXPECTED TO BUILD ACROSS THE UPPER MIDWEST...BRINGING A WARMING TREND FOR LATE NEXT WEEK...WITH TEMPS POSSIBLY REACHING THE LOWER TO MIDDLE 40S BY NEXT FRIDAY. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * CIGS AROUND 2000 FT SCATTERING SOME TIME LATE THIS AFTERNOON. * N-NNE WINDS 12-15 KT GUSTING TO 20-22 KT AT TIMES THROUGH THE AFTERNOON. KMD //DISCUSSION...UPDATED 12Z... LOW PRESSURE CONTINUES TO MOVE NORTHEAST UP THE OHIO RIVER VALLEY WHILE HIGH PRESSURE MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. STEADIER N TO NE WINDS HAVE SET UP IN THE 10-14 KT RANGE WITH SPORADIC GUSTS ALSO APPEARING AT TIMES. GUSTS WILL LIKELY BECOME MORE FREQUENT THIS AFTERNOON ESPECIALLY WHERE BREAKS CAN DEVELOP IN THE CLOUD COVER. WINDS WILL GRADUALLY DIMINISH AND TURN NORTHEAST THIS EVENING BEFORE SHIFTING SOUTHEAST TOWARD DAYBREAK MONDAY. CIGS WILL BE A CHALLENGE THROUGH THE MORNING. OBS SHOW BASE HEIGHTS RANGING FROM 600-1100 FT ACROSS THE TERMINALS AND POINTS UPSTREAM. A SLIGHT WIND COMPONENT OFF THE LAKE SEEMS TO BE KEEPING BASES A LITTLE HIGHER WITHIN SEVERAL MILES INLAND OF THE SHORE THANKS TO WARMER AIR OVER THE WATER. SATELLITE IMAGERY SHOWS A WELL DEFINED BACK EDGE TO THE STRATUS ACROSS SOUTHERN WISCONSIN WHICH IS MOVING SOUTHEAST. STRATUS IS ALSO EXTENSIVE ACROSS LAKE MICHIGAN. THE BACK EDGE OF THIS STRATUS WILL LIKELY WORK ACROSS MOST OF IF NOT ALL OF THE AREA THROUGH AROUND 16Z. HOWEVER...THERE IS NOT SIGNIFICANT AMOUNTS OF DRY AIR WORKING INTO THE REGION SO SCT-BKN STRATO CU MAY DEVELOP TOWARD MIDDAY....PROVIDED THE CURRENT BAND DOES EXIT AND DOES NOT SLOW ITS SOUTHWARD PROGRESS. IN OTHER WORDS THERE MAY BE A BREAK IN THE LOW CLOUDS BEFORE DIURNAL CU DEVELOPS. ALSO...FLOW IN THE CLOUD LAYER WILL BE AIMED FROM THE NORTHEAST RIGHT ACROSS THE LAKE SO LAKE PROCESSES MAY BE SUFFICIENT TO KEEP STRATUS GOING AT LEAST WITHIN SEVERAL MILES OF SHORE WELL INTO THE AFTERNOON. WILL GO AHEAD AND KEEP A LONGER PERIOD OF STRATUS IN THE FORECAST FOR NOW WHICH COULD BE PESSIMISTIC. OTHERWISE SKIES WILL CLEAR THIS EVENING IF THEY DO NOT DO SO EARLIER. MORNING VSBY BETWEEN 2-5 SM WILL IMPROVE AS WE GRADUALLY BEGIN TO WARM UP AFTER DAYBREAK. MDB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * LOW CONFIDENCE IN TIMING OF SCATTERING THE MVFR CLOUD DECK LATER TODAY. * HIGH CONFIDENCE IN WIND TRENDS. KMD //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...MAINLY VFR. SLGT CHANCE OF LIGHT SNOW/SLEET AND MVFR SUNDAY. E WINDS BECOMING SE. MONDAY...CHANCE RAIN/SLEET/SNOW. MVFR/BRIEF IFR POSSIBLE. S WINDS BECOMING W. TUESDAY...VFR. NW WINDS BECOMING N. WEDNESDAY...VFR. NE WINDS BECOMING ESE. THURSDAY...SLGT CHANCE LIGHT SNOW. VFR. S WINDS. FRIDAY...VFR. SSE WINDS. MDB && .MARINE... 256 AM CST LOW PRESSURE CONTINUES TO MOVE NORTHEAST UP THE OHIO RIVER VALLEY EARLY THIS MORNING WITH STRONG HIGH PRESSURE MOVING EASTWARD ACROSS THE EASTERN DAKOTAS. WINDS ARE STARTING TO INCREASE AS THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS TIGHTENS UP THROUGH THE MORNING. AS A RESULT...EXPECT NORTH TO NORTHEAST WINDS TO RANGE FROM 20 TO 25 KT WITH GUSTS TO 30 KT ACROSS THE CENTRAL AND SOUTHERN PARTS OF THE LAKE THIS MORNING/AFTERNOON WITH NORTHERN AREAS DIMINISHING THROUGH THE AFTERNOON AS THE INFLUENCE OF THE HIGH ARRIVES. SPEEDS WILL DIMINISH ACROSS THE LAKE THIS EVENING AND TONIGHT AS THE DIRECTION TURNS EAST THEN SOUTHEAST AS THE HIGH SHIFTS TO THE EAST. WILL CONTINUE WITH THE SMALL CRAFT ADVISORY INTO EARLY TONIGHT AS THE LONG FETCH OF WIND WILL KEEP WAVES ELEVATED AFTER WINDS DIMINISH THIS EVENING. LOW PRESSURE WILL DEVELOP IN THE LEE OF THE NORTHERN ROCKIES SUNDAY AND MOVE EASTWARD ALONG THE U.S./CANADIAN BORDER...CROSSING LAKE SUPERIOR MONDAY EVENING. THE LOW WILL DRAG A COLD FRONT ACROSS THE LAKE MONDAY EVENING. SOUTHERLY WINDS WILL INCREASE AHEAD OF THE LOW SUNDAY AND SUNDAY NIGHT THEN SHIFT TO THE NORTHWEST BEHIND THE FRONT MONDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD IN BEHIND THE LOW INTO TUESDAY WITH A FAIRLY STRONG PUSH OF COLDER AIR AND A TIGHT PRESSURE GRADIENT SUPPORTING GUSTY NORTH TO NORTHWEST WINDS. WINDS WILL DIMINISH WEDNESDAY AS THE HIGH MOVES OVERHEAD. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 940 AM CST Sat Dec 6 2014 .UPDATE... ISSUED AT 939 AM CST SAT DEC 6 2014 Main concern for today is with cloud cover. Widespread stratus covers the forecast area this morning, with ceilings east of I-57 managing to reach just above 1000 feet while they remain 500 feet or less most areas west. This morning`s upper air sounding, plus forecast soundings off the latest NAM and RAP models, show a persistent inversion around 950 mb. There is some clearing that has occurred over the northwest corner of Illinois, but visible satellite loops showing only slow southern progress toward the Quad Cities area. We`re in the time of year where low sun angle makes it difficult to burn off the low clouds. Areas northwest of Peoria most likely to see any sun this afternoon although there will still be quite a few clouds around. The remainder of the CWA should remain mainly cloudy. Going forecast is in pretty good shape, and only required some minor tweaks to incorporate current trends. && .SHORT TERM...(Today) ISSUED AT 323 AM CST SAT DEC 6 2014 The 08z/2am surface analysis has a 1015mb low in NC Kentucky moving northeast along a stationary front. Rain showers on the NW flank of the low are steadily progressing eastward out of our E-SE counties. The back edge of precip should reach I-57 by 09z/3am and be completely out of our IL counties by 13z/7am. Despite dry air aloft flowing into Illinois on N-NW winds, a strong subsidence inversion is indicated in all the short term models. That will limit mixing of the dry air in to the low level moisture, and work to keep clouds across our forecast area over the next 12 hours if not well into tonight. The satellite images are showing a clearing line progressing south toward IL across MN/WI, however, that clearing should slow down with the intensification of the inversion today. High temps will not climb appreciably under the blanket of clouds, with readings topping out in the upper 30s toward Galesburg and into the mid 40s toward Lawrenceville. && .LONG TERM...(Tonight through Friday) ISSUED AT 323 AM CST SAT DEC 6 2014 High pressure continues to build into the region, although the inversion remains and will likely see a continuation of the clouds until the incredibly dry air aloft finally works its way down into the higher RH in the llvls. This same dry air is also the deciding factor in the next issue for the forecast with an approaching wave Sun night/Monday. Prev models had more disagreement and the NAM with a more southerly track for the wave was the outlier. With this run, both the GFS and ECMWF starting to look a lot more like the prev NAM. A small system developing into a larger upper trof late in the weekend...with the look of two smaller waves bringing pops back into the region. Although the GFS and the ECMWF are more consistent with the prev NAM, the NAM is far more scarce with the QPF. Keeping the forecast chances low for shower activity after midnight Sun night/Monday... not only for lack of continuity from run to run, but the considerable amount of dry air will take a while to overcome. Not convinced the best lift will coincide with the eventual saturation of the column. Beyond Monday and its cold front, temps cool briefly, then moderate back into the 40s for highs through the end of the week. 00z ECMWF completely pulls back on a small disturbance Wed night/Thursday, and should this trend continue, will likely pull the pops altogether out of the next couple runs. For now, slight pops in the forecast to cover a brief disturbance diving into the Great Lakes region on the retreating edge of the larger scale 500 mb trof exiting out to the northeast. This difference btwn the GFS and the European also delineates the break point in the extended between any agreement in the midst of a small pattern shift. Depth of the thickness ridge going into day 7 and 8 will definitely result in some blend issues going into next weekend. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) ISSUED AT 600 AM CST SAT DEC 6 2014 The cloud forecast will continue to be challenging over the next 24 hours, as a clearing line approaches central IL from the north. However, the HRRR and NAM keep low clouds entrenched until later this evening, while the GFS dissipates the low clouds this morning. The HRRR does show the brief small area of break in the low clouds that drifted across the area the last 6 hours, but it also indicates that break will fill in and the clearing line will barely graze our NW counties this afternoon, but not reach all the way to PIA. The NAM/SREF/RAP forecast soundings all show a strong subsidence inversion trapping the low level moisture across our terminal sites today. So confidence is moderate in keeping low clouds in place through the day. Ceiling heights will start out LIFR at BMI/DEC and IFR at PIA/CMI/SPI. All ceilings should at least climb to MVFR after 18z with heating of the day and lifting of the LCL. We went with some clearing eventually developing tonight with advancing high pressure and a deeper layer of dry air. Winds will remain north today at 10-14kt and shift to northeast tonight as they diminish below 10kt. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...Shimon LONG TERM...HJS AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1137 AM EST SAT DEC 6 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 356 AM EST SAT DEC 6 2014 RAINFALL WILL COME TO AN END TODAY AS LOW PRESSURE GRADUALLY EXITS THE REGION. CLOUD COVER WILL PERSIST HOWEVER AS AMPLE LOW LEVEL MOISTURE REMAINS TRAPPED UNDER A STRONG INVERSION. DRY WEATHER WILL CONTINUE THROUGH SUNDAY NIGHT AS HIGH PRESSURE DOMINATES THE REGION. A SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE GREAT LAKES MONDAY AND MONDAY NIGHT MAY PRODUCE SOME LIGHT RAIN ACROSS PORTIONS OF THE AREA. DRY WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD. && .NEAR TERM /REST OF TODAY/... ISSUED AT 948 AM EST SAT DEC 6 2014 RAINFALL HAS EXITED THE FORECAST AREA FOR THE MOST PART...SO WILL TAKE OUT POPS FOR THE REST OF THE DAY. SHORT TERM MODELS SUGGEST LITTLE CHANCE OF ANY SIGNIFICANT CLEARING TODAY. THICK CLOUD COVER COMBINED WITH LOW LEVEL COLD ADVECTION SUGGESTS ONLY SUBTLE TEMPERATURE RISES FOR THE REST OF THE DAY. PREVIOUS DISCUSSION FOLLOWS. BETWEEN HRRR AND EXTRAPOLATION FROM LATEST RADAR TRENDS...EXPECT PRECIPITATION TO COME TO AN END ACROSS CENTRAL INDIANA BY NOON...AND WILL RAPIDLY TAPER OFF POPS AS SUCH FROM WEST TO EAST. STRONG LOW LEVEL INVERSION WILL REMAIN ACROSS THE AREA IN THE WAKE OF THE LOW PRESSURE SYSTEM WITH MOISTURE TRAPPED...THUS IT APPEARS THAT MODEL GUIDANCE IS CLEARING SKIES OUT FAR TOO QUICKLY. HAVE DELAYED ANY CLEARING WHATSOEVER INTO THE AFTERNOON AND THERE IS SOME CHANCE EVEN THIS IS TOO EARLY. LEANED SLIGHTLY COOLER THAN GUIDANCE AS A RESULT OF THIS AMPLE CLOUD COVER AND ONGOING COLD ADVECTION THROUGH THE DAY. MAY SEE HIGH TEMPERATURES EARLY IN THE DAY IN SOME LOCATIONS WITH TEMPERATURES STEADY OR SLOWLY FALLING LATE IN THE DAY. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... ISSUED AT 356 AM EST SAT DEC 6 2014 LATEST MODELS ARE COMING IN WETTER WITH THE SURFACE AND UPPER LEVEL TROUGH PASSING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. WILL HAVE TO CARRY SOME POPS MONDAY AND INTO MONDAY EVENING...BUT WITH SOUNDINGS ONLY BRIEFLY SATURATING MONDAY...AND DRYING QUICKLY FROM ALOFT LATE MONDAY NIGHT...WILL GO NO FURTHER THAN LOW CHANCE POPS AND WILL END PRECIP BY 06Z MONDAY NIGHT. MONDAY EVENING...PRECIP MAY COME MORE IN THE FORM OF DRIZZLE AS DRY AIR WORKS INTO THE AREA ALOFT BUT WITH WEAKLY POSITIVE OMEGA NOTED IN MOIST LOW LEVELS. EXPECT THAT PRECIP WILL HAVE ENDED BY THE TIME ANY FREEZING OR NEAR FREEZING TEMPERATURES MOVE INTO THE AREA. MODEL CONSENSUS APPEARED TO TRACK RELATIVELY WELL WITH LOW LEVEL THICKNESS PROGS...ASIDE FROM A FEW MINOR TWEAKS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... ISSUED AT 220 AM EST SAT DEC 6 2014 DRY WEATHER IS EXPECTED THIS PERIOD AS THE GFS SHOWS A DEPARTING TROUGH OF LOW PRESSURE ON TUESDAY AND HIGH PRESSURE OVER THE PLAINS STATES BEGINNING TO BUILD ACROSS THE AREA FOR THE MIDDLE OF THE NEXT WORK WEEK. AS THE SURFACE HIGH PUSHES EAST OF INDIANA ON THURSDAY THE GFS DEPICTS ABUNDANT MOISTURE ALOFT IN THE RETURN FLOW. MEANWHILE THE ECMWF IS MUCH LESS AGGRESSIVE. GIVEN THE LACK OF DYNAMICS ALOFT...HAVE LEANED TOWARD THE DRYER ECMWF SOLUTION FOR NOW. STRONG RIDGING BUILDS ALOFT AS THE WORK WEEK COMES TO AN END...AS SOUTHERLY TO SOUTHWEST SURFACE WINDS KEEP COLDER ARCTIC AIR AT BAY. THUS WILL CONTINUE THROUGH THE PERIOD WITH AT OR ABOVE NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 061800Z TAFS/... ISSUED AT 1137 AM EST SAT DEC 6 2014 A LARGE AREA OF MVFR CEILINGS 015-025 CURRENTLY ACROSS THE AREA. SHORT TERM MODELS SUGGEST THESE CONDITIONS WILL HOLD THROUGH THE EVENING HOURS...WITH THE POTENTIAL FOR SCATTERING OUT OF THE CEILINGS FROM NORTH TO SOUTH TOWARDS 070600Z. SURFACE WIND GUSTS 20-22 KTS FROM 360-020 DEGREES SHOULD CONTINUE FOR THE AFTERNOON HOURS...DIMINISHING AROUND SUNSET. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NIELD NEAR TERM...NIELD/JAS SHORT TERM...NIELD LONG TERM...PUMA AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
1141 AM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 1042 AM CST SAT DEC 6 2014 CURRENT SATELLITE SHOWS THE EXTENT OF THE CLOUD COVER FROM PELLA...JUST SOUTH OF IOWA CITY TO PRINCETON. THIS CLOUD DECK HAD SLOWED DOWN EARLIER WITH NE WINDS OFF THE LAKE. IN THE LAST COUPLE OF HOURS THE CLEARING BEGAN TO INCREASE AND THE CLOUD DECK MOVED SOUTH. HAD TO UPDATE THE CLOUD FORECAST TO TIME THE CURRENT DECK BETTER. TIMING TOOL SUGGESTS SOUTHERN CWA WILL NOT CLEAR UNTIL MID AFTERNOON. AS A RESULT TEMPS WILL BE WARMER IN THE NORTH THAN THE SOUTH THIS AFTERNOON BY A COUPLE OF DEGREES. LOADED THE RUC HIGH TEMPS AND THEN ADJUSTED CERTAIN SITES DOWN OR UP TO REPRESENT THE CLOUD DECK ACROSS THE AREA. OTHERWISE...THE REST OF THE FORECAST LOOKS GOOD. UPDATE ISSUED AT 413 AM CST SAT DEC 6 2014 ADDED PATCHY DENSE FOG IN THE RIVER VALLEYS ACROSS THE NORTHERN CWA. CLEARING HAS ALREADY ENTERED INTO NORTHERN IOWA AND CONTINUES TO PUSH SOUTHWARD. FURTHER UPSTREAM...AREAS OF DENSE RADIATION FOG HAVE DEVELOPED IN SOUTHERN MINNESOTA WITH SOME REPORTED VISIBILITIES DOWN TO 1/4 SM. AGAIN...ANY DENSE FOG THAT DEVELOPS OVER THE NEXT SEVERAL HOURS SHOULD BE FOCUSED IN LOW-LYING AREAS. ALSO UPDATED SKY COVER THROUGH THE DAY WITH A FASTER NORTH TO SOUTH BREAK UP OF THE STRATUS. && .SYNOPSIS... ISSUED AT 323 AM CST SAT DEC 6 2014 OVERVIEW...MID AND UPPER LEVEL FLOW BECOMES NORTHWESTERLY TODAY WITH THE MIDWEST IN BETWEEN A SHORTWAVE TROUGH OVER BOTH THE EAST AND WEST COASTS. 850 MB RIDGE AXIS WILL POSITION RIGHT ACROSS THE UPPER MISSISSIPPI VALLEY REGION INTO SUNDAY MORNING. NO PRECIPITATION IS FORECAST DURING THIS TIME AS THE NORTHWEST FLOW AND LARGE SCALE SUBSIDENCE CONTINUE TO DRY OUT THE COLUMN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 323 AM CST SAT DEC 6 2014 TODAY...CHALLENGE FOR TODAY WILL BE THE EXTENT AND PERSISTENCE OF VERY LOW STRATUS CLOUDS. CURRENTLY...SFC OBSERVING STATIONS IN THE DVN CWA ARE REPORTING CEILINGS BETWEEN 300-600 FT AGL WITH NO SIGNS OF IMPROVEMENT SO FAR THROUGH THIS EVENING/OVERNIGHT. 11-3.9 MICRON IR FOG PRODUCT DEPICTS THE CLEARING LINE TO NOW BE SOUTH OF KLSE WITH A SLOW BUT STEADY SOUTHWARD PROGRESSION. NAM/RAP FORECAST A VERY DRY COLUMN THROUGH THE DAY WITH THE EXCEPTION OF A RESIDUAL MOIST LAYER THAT BECOMES TRAPPED AT AROUND 950-975 MB BENEATH A LARGE-SCALE SUBSIDENCE INVERSION. SOUNDINGS ARE MORE SATURATED AT DAVENPORT AND POINTS SOUTHWARD AND LESS TO THE N/NW. BEST CHANCES FOR CLEARING ARE N OF QUAD CITIES DURING THE MORNING...THEN ALL BUT THE FAR SOUTHERN PORTION OF THE FORECAST AREA DURING THE AFTN. NOT MUCH VARIATION IN SFC TEMPS TODAY WITH A SPREAD OF ONLY MID TO UPPER 30S. TONIGHT...LOW-LEVEL STRATUS SHOULD GET SCOURED OUT FOR MOST PLACES BUT ANY CLEARING WILL BE BRIEF AS MID-LEVEL CLOUDS BEGIN TO STREAM IN FROM THE SW AHEAD OF THE NEXT SHORTWAVE TROUGH SHIFTING EAST OF THE ROCKIES. WEAK 1000-500 MB POSITIVE THICKNESS ADVECTION WILL ENSUE AFTER 06Z/SUNDAY AS MID-LEVEL WINDS BACK FROM NW TO SW. LOWS IN MID 20S WILL BE A FEW DEGREES ABOVE AVG. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 323 AM CST SAT DEC 6 2014 EARLY CHALLENGE IS THE SYSTEM MOVING INTO THE PACIFIC NW THAT WILL BRING A GOOD POTENTIAL FOR LIGHT PRECIPITATION...POSSIBLY IN THE FORM OF A WINTRY MIX...OVER THE AREA SUNDAY NIGHT INTO MONDAY MORNING. DRY AND NEAR TO BELOW NORMAL TEMPERATURES WILL FOLLOW TUE AND WED WITH PASSING HIGH PRESSURE. MODEL RUNS OVER THE PAST 24 HOURS HAVE TRENDED TOWARD A MORE AMPLIFIED UPPER LEVEL FLOW NEXT WEEK RESULTING FROM A DEEPER UPPER LOW NOW DEPICTED OVER THE MID ATLANTIC COAST AND THE NE U.S. LATE WED THROUGH FRI. THIS SUGGESTS A LOWER CONFIDENCE LATE WEEK PERIOD WITH EVEN A POTENTIAL FOR AT LEAST LIGHT PRECIPITATION AS THIS BLOCKING LOW MAY DELAY THE EASTWARD PROGRESSION OF THE WESTERN U.S. UPPER RIDGE AND KEEP A MORE ACTIVE...N-NW UPPER LEVEL FLOW IN PLACE OVERHEAD LATER INTO THE WEEK. SUNDAY THROUGH MONDAY...THE UPPER LEVEL SYSTEM OFF THE NW COAST IS EXPECTED TO STRENGTHEN AND THEN PHASE WITH NORTHERN STREAM ENERGY...DIGGING A LONGWAVE TROUGH OVER THE EASTERN U.S. TOWARD MID WEEK. AS IT PASSES TO THE NORTH LATE SUNDAY NIGHT...IT SENDS A ROUND OF MID LEVEL QG FORCING OVER THE FORECAST AREA ABOVE LOW LEVEL WARM ADVECTION AND MODEST MOISTURE RETURN. TOP DOWN APPROACH FROM FORECAST SOUNDINGS SUGGESTS A POSSIBLE RAIN/SNOW/SLEET MIX ACROSS THE NORTHERN HALF OF THE FORECAST AREA...WITH RAIN/SNOW CENTRAL AND MAINLY RAIN SOUTH...WHICH MAY CHANGE TO PRIMARILY RAIN OVER ALL BUT THE FAR NORTHEAST WITH WARMING LOW LEVELS TOWARD MORNING. CONFIDENCE REMAINS LOW IN THE MODEL DEPICTION OF CRITICAL LOW LEVEL THERMAL PROFILES AND FURTHER ADJUSTMENTS TO PRECIPITATION TYPES WILL LIKELY BE NEEDED. WITH THE SURFACE LOW TRACKING WELL TO THE NORTH AND MODEST LIFT...QPF FOR THE EVENT SHOULD BE LESS THAN A TENTH OF AN INCH WITH LITTLE IF ANY ACCUMULATION OF SLEET OR SNOW NORTH. WITH THE SYSTEM SLOWING SOME...HAVE EXTENDED POPS INTO MONDAY MORNING OVER THE EAST FOR WHAT WOULD LIKELY BE RAIN OR RAIN/SNOW MIX. TEMPERATURES MAY REACH INTO THE MID 40S IN THE SOUTH BEFORE THE COLD FRONT PUSHES THROUGH IN THE AFTERNOON. TUESDAY THROUGH TUE NIGHT...PASSING HIGH PRESSURE RIDGE WILL LIMIT HIGHS TO THE 30S WITH OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. WEDNESDAY THROUGH FRIDAY...THE 00Z GFS...GEM AND ECMWF OFFER VARYING SOLUTIONS WITH THE TIMING AND TRACK OF THE NEXT SHORTWAVE IN THE NW FLOW AROUND MID WEEK...AND HOW FAST THE LARGE UPPER LOW EXITS THE NORTHEAST. THE GFS AND GEM ARE IN ONE CAMP WITH LIGHT PRECIPITATION DEVELOPING WITH THE NEXT SHORTWAVE IN THE NW FLOW AND ALONG A WARM FRONT WED INTO WED NIGHT OVER ESPECIALLY THE SOUTH...THEN OVER THE ENTIRE AREA WED NIGHT...WHEREAS THE ECMWF IS DRY WITH A SURFACE RIDGE IN PLACE. RESULTING MODEL CONSENSUS BLENDS OF QPF AND POP FIELDS SUGGESTED SEVERAL PERIODS OF LIGHT PRECIPITATION FROM WED THROUGH FRI. WITH LOW CONFIDENCE IN THESE PERIODS DUE TO THE POOR CONSISTENCY AND LACK OF AGREEMENT...HAVE KEPT ONLY SLIGHT CHANCES FOR WHAT WOULD LIKELY BE LIGHT RAIN CONFINED TO ONLY WED NIGHT. TEMPERATURES SHOULD STILL MODERATE WITH HIGHS BACK INTO THE 40S THU AND FRI OVER ESPECIALLY THE SOUTH...BUT THE WELL ADVERTISED TRANSITION TO MUCH ABOVE NORMAL TEMPERATURES MAY BE DELAYED TO NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1132 AM CST SAT DEC 6 2014 MAIN CONCERN FOR AVIATION IN THE SHORT TERM ARE THE IFR CLOUD DECK MOVING OUT OF THE AREA. THE ONLY TAF SITE AFFECTED BY THIS IS BRL AND SHOULD SEE THE DECK OUT BY 2100Z AT THE LATEST. ONCE THE DECK MOVES OUT VFR CONDITIONS WILL PERSIST DURING THE PERIOD. THE NAM APPEARS TO HAVE PROBLEMS WITH BOUNDARY LAYER MOISTURE AGAIN AND SUGGESTS THAT LOW CLOUDS WILL AFFECT THE TAF SITES TONIGHT. THAT DOES NOT LOOK LIKELY AT ALL...SO DID NOT USE THE NAM DUE TO MODEL ISSUES. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...GIBBS SYNOPSIS...UTTECH SHORT TERM...UTTECH LONG TERM...SHEETS AVIATION...GIBBS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
1048 AM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 1042 AM CST SAT DEC 6 2014 CURRENT SATELLITE SHOWS THE EXTENT OF THE CLOUD COVER FROM PELLA...JUST SOUTH OF IOWA CITY TO PRINCETON. THIS CLOUD DECK HAD SLOWED DOWN EARLIER WITH NE WINDS OFF THE LAKE. IN THE LAST COUPLE OF HOURS THE CLEARING BEGAN TO INCREASE AND THE CLOUD DECK MOVED SOUTH. HAD TO UPDATE THE CLOUD FORECAST TO TIME THE CURRENT DECK BETTER. TIMING TOOL SUGGESTS SOUTHERN CWA WILL NOT CLEAR UNTIL MID AFTERNOON. AS A RESULT TEMPS WILL BE WARMER IN THE NORTH THAN THE SOUTH THIS AFTERNOON BY A COUPLE OF DEGREES. LOADED THE RUC HIGH TEMPS AND THEN ADJUSTED CERTAIN SITES DOWN OR UP TO REPRESENT THE CLOUD DECK ACROSS THE AREA. OTHERWISE...THE REST OF THE FORECAST LOOKS GOOD. UPDATE ISSUED AT 413 AM CST SAT DEC 6 2014 ADDED PATCHY DENSE FOG IN THE RIVER VALLEYS ACROSS THE NORTHERN CWA. CLEARING HAS ALREADY ENTERED INTO NORTHERN IOWA AND CONTINUES TO PUSH SOUTHWARD. FURTHER UPSTREAM...AREAS OF DENSE RADIATION FOG HAVE DEVELOPED IN SOUTHERN MINNESOTA WITH SOME REPORTED VISIBILITIES DOWN TO 1/4 SM. AGAIN...ANY DENSE FOG THAT DEVELOPS OVER THE NEXT SEVERAL HOURS SHOULD BE FOCUSED IN LOW-LYING AREAS. ALSO UPDATED SKY COVER THROUGH THE DAY WITH A FASTER NORTH TO SOUTH BREAK UP OF THE STRATUS. && .SYNOPSIS... ISSUED AT 323 AM CST SAT DEC 6 2014 OVERVIEW...MID AND UPPER LEVEL FLOW BECOMES NORTHWESTERLY TODAY WITH THE MIDWEST IN BETWEEN A SHORTWAVE TROUGH OVER BOTH THE EAST AND WEST COASTS. 850 MB RIDGE AXIS WILL POSITION RIGHT ACROSS THE UPPER MISSISSIPPI VALLEY REGION INTO SUNDAY MORNING. NO PRECIPITATION IS FORECAST DURING THIS TIME AS THE NORTHWEST FLOW AND LARGE SCALE SUBSIDENCE CONTINUE TO DRY OUT THE COLUMN. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 323 AM CST SAT DEC 6 2014 TODAY...CHALLENGE FOR TODAY WILL BE THE EXTENT AND PERSISTENCE OF VERY LOW STRATUS CLOUDS. CURRENTLY...SFC OBSERVING STATIONS IN THE DVN CWA ARE REPORTING CEILINGS BETWEEN 300-600 FT AGL WITH NO SIGNS OF IMPROVEMENT SO FAR THROUGH THIS EVENING/OVERNIGHT. 11-3.9 MICRON IR FOG PRODUCT DEPICTS THE CLEARING LINE TO NOW BE SOUTH OF KLSE WITH A SLOW BUT STEADY SOUTHWARD PROGRESSION. NAM/RAP FORECAST A VERY DRY COLUMN THROUGH THE DAY WITH THE EXCEPTION OF A RESIDUAL MOIST LAYER THAT BECOMES TRAPPED AT AROUND 950-975 MB BENEATH A LARGE-SCALE SUBSIDENCE INVERSION. SOUNDINGS ARE MORE SATURATED AT DAVENPORT AND POINTS SOUTHWARD AND LESS TO THE N/NW. BEST CHANCES FOR CLEARING ARE N OF QUAD CITIES DURING THE MORNING...THEN ALL BUT THE FAR SOUTHERN PORTION OF THE FORECAST AREA DURING THE AFTN. NOT MUCH VARIATION IN SFC TEMPS TODAY WITH A SPREAD OF ONLY MID TO UPPER 30S. TONIGHT...LOW-LEVEL STRATUS SHOULD GET SCOURED OUT FOR MOST PLACES BUT ANY CLEARING WILL BE BRIEF AS MID-LEVEL CLOUDS BEGIN TO STREAM IN FROM THE SW AHEAD OF THE NEXT SHORTWAVE TROUGH SHIFTING EAST OF THE ROCKIES. WEAK 1000-500 MB POSITIVE THICKNESS ADVECTION WILL ENSUE AFTER 06Z/SUNDAY AS MID-LEVEL WINDS BACK FROM NW TO SW. LOWS IN MID 20S WILL BE A FEW DEGREES ABOVE AVG. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 323 AM CST SAT DEC 6 2014 EARLY CHALLENGE IS THE SYSTEM MOVING INTO THE PACIFIC NW THAT WILL BRING A GOOD POTENTIAL FOR LIGHT PRECIPITATION...POSSIBLY IN THE FORM OF A WINTRY MIX...OVER THE AREA SUNDAY NIGHT INTO MONDAY MORNING. DRY AND NEAR TO BELOW NORMAL TEMPERATURES WILL FOLLOW TUE AND WED WITH PASSING HIGH PRESSURE. MODEL RUNS OVER THE PAST 24 HOURS HAVE TRENDED TOWARD A MORE AMPLIFIED UPPER LEVEL FLOW NEXT WEEK RESULTING FROM A DEEPER UPPER LOW NOW DEPICTED OVER THE MID ATLANTIC COAST AND THE NE U.S. LATE WED THROUGH FRI. THIS SUGGESTS A LOWER CONFIDENCE LATE WEEK PERIOD WITH EVEN A POTENTIAL FOR AT LEAST LIGHT PRECIPITATION AS THIS BLOCKING LOW MAY DELAY THE EASTWARD PROGRESSION OF THE WESTERN U.S. UPPER RIDGE AND KEEP A MORE ACTIVE...N-NW UPPER LEVEL FLOW IN PLACE OVERHEAD LATER INTO THE WEEK. SUNDAY THROUGH MONDAY...THE UPPER LEVEL SYSTEM OFF THE NW COAST IS EXPECTED TO STRENGTHEN AND THEN PHASE WITH NORTHERN STREAM ENERGY...DIGGING A LONGWAVE TROUGH OVER THE EASTERN U.S. TOWARD MID WEEK. AS IT PASSES TO THE NORTH LATE SUNDAY NIGHT...IT SENDS A ROUND OF MID LEVEL QG FORCING OVER THE FORECAST AREA ABOVE LOW LEVEL WARM ADVECTION AND MODEST MOISTURE RETURN. TOP DOWN APPROACH FROM FORECAST SOUNDINGS SUGGESTS A POSSIBLE RAIN/SNOW/SLEET MIX ACROSS THE NORTHERN HALF OF THE FORECAST AREA...WITH RAIN/SNOW CENTRAL AND MAINLY RAIN SOUTH...WHICH MAY CHANGE TO PRIMARILY RAIN OVER ALL BUT THE FAR NORTHEAST WITH WARMING LOW LEVELS TOWARD MORNING. CONFIDENCE REMAINS LOW IN THE MODEL DEPICTION OF CRITICAL LOW LEVEL THERMAL PROFILES AND FURTHER ADJUSTMENTS TO PRECIPITATION TYPES WILL LIKELY BE NEEDED. WITH THE SURFACE LOW TRACKING WELL TO THE NORTH AND MODEST LIFT...QPF FOR THE EVENT SHOULD BE LESS THAN A TENTH OF AN INCH WITH LITTLE IF ANY ACCUMULATION OF SLEET OR SNOW NORTH. WITH THE SYSTEM SLOWING SOME...HAVE EXTENDED POPS INTO MONDAY MORNING OVER THE EAST FOR WHAT WOULD LIKELY BE RAIN OR RAIN/SNOW MIX. TEMPERATURES MAY REACH INTO THE MID 40S IN THE SOUTH BEFORE THE COLD FRONT PUSHES THROUGH IN THE AFTERNOON. TUESDAY THROUGH TUE NIGHT...PASSING HIGH PRESSURE RIDGE WILL LIMIT HIGHS TO THE 30S WITH OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. WEDNESDAY THROUGH FRIDAY...THE 00Z GFS...GEM AND ECMWF OFFER VARYING SOLUTIONS WITH THE TIMING AND TRACK OF THE NEXT SHORTWAVE IN THE NW FLOW AROUND MID WEEK...AND HOW FAST THE LARGE UPPER LOW EXITS THE NORTHEAST. THE GFS AND GEM ARE IN ONE CAMP WITH LIGHT PRECIPITATION DEVELOPING WITH THE NEXT SHORTWAVE IN THE NW FLOW AND ALONG A WARM FRONT WED INTO WED NIGHT OVER ESPECIALLY THE SOUTH...THEN OVER THE ENTIRE AREA WED NIGHT...WHEREAS THE ECMWF IS DRY WITH A SURFACE RIDGE IN PLACE. RESULTING MODEL CONSENSUS BLENDS OF QPF AND POP FIELDS SUGGESTED SEVERAL PERIODS OF LIGHT PRECIPITATION FROM WED THROUGH FRI. WITH LOW CONFIDENCE IN THESE PERIODS DUE TO THE POOR CONSISTENCY AND LACK OF AGREEMENT...HAVE KEPT ONLY SLIGHT CHANCES FOR WHAT WOULD LIKELY BE LIGHT RAIN CONFINED TO ONLY WED NIGHT. TEMPERATURES SHOULD STILL MODERATE WITH HIGHS BACK INTO THE 40S THU AND FRI OVER ESPECIALLY THE SOUTH...BUT THE WELL ADVERTISED TRANSITION TO MUCH ABOVE NORMAL TEMPERATURES MAY BE DELAYED TO NEXT WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 545 AM CST SAT DEC 6 2014 PATCHY DENSE RADIATION FOG MAY DEVELOP AT KCID AND KDBQ PRIOR TO 15Z TODAY AS STRATUS DECK BEGINS TO BREAK APART AND TEMPS FALL. CONDITIONS WILL THEN SLOWLY IMPROVE THROUGH THIS MORNING FROM NORTH TO SOUTH. BY MIDDAY...VFR IS ANTICIPATED AT ALL TERMINALS EXCEPT KBRL WHERE PERIODS OF IFR/LIFR WILL LIKELY CONTINUE. A STRONG SUBSIDENCE INVERSION WILL MAKE IT DIFFICULT TO MIX OUT MOISTURE TRAPPED AROUND 950 MB OR BELOW 1 KFT AGL. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...GIBBS SYNOPSIS...UTTECH SHORT TERM...UTTECH LONG TERM...SHEETS AVIATION...UTTECH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
400 PM MST SAT DEC 6 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 207 PM MST SAT DEC 6 2014 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW PROGRESSIVE TROUGH-RIDGE TROUGH PATTERN ACROSS US WITH RIDGE CURRENTLY EXTENDING FROM SOUTH CENTRAL CANADA ACROSS THE CENTRAL PLAINS. SW FLOW IS IN PLACE FROM THE FOUR CORNERS REGION AND INTO WESTERN KS WITH SHORTWAVE TROUGH MOVING OUT OF THE GREAT BASIN TOWARDS THE CENTRAL ROCKIES. AT THE SURFACE LEE TROUGH IS IN PLACE OVER EASTERN COLORADO WITH SOUTHERLY FLOW ACROSS OUR CWA. AS SHORTWAVE TROUGH TRANSITIONS EASTWARD STATIONARY FRONT/BAROCLINIC ZONE WITH SHIFT NORTH AND EAST ALLOWING FOR SOUTHEAST MOISTURE RETURN INTO THE EASTERN HALF OF OUR CWA. MIDLEVEL MOISTURE/UPPER LEVEL FORCING COULD ALLOW FOR A BRIEF PERIOD OF LIGHT RAIN SHOWERS LATE TONIGHT...HOWEVER MODEL SOUNDINGS INDICATE A SIGNIFICANT DRY LAYER WOULD LIKELY PREVENT ANY ELEVATED PRECIPITATION FROM REACHING THE SURFACE. MAIN CONCERN WILL BE POTENTIAL FOR DENSE FOG DEVELOPMENT AND POTENTIAL FOR DRIZZLE ACROSS EASTERN CWA LATE TONIGHT THROUGH SUNDAY MORNING. NAM/RAP SHOW WEAK SURFACE CONVERGENCE IN PROXIMITY OF BAROCLINIC ZONE WHICH COULD PROVIDE ENOUGH LIFT WITHIN SHALLOW SATURATED LAYER TO ALLOW FOR DRIZZLE DEVELOPMENT. THIS COULD BE MORE OF A STRATUS/DRIZZLE EVENT...THOUGH CONSIDERING THE GOOD MOISTURE RETURN LOWER VISIBILITIES ARE CERTAINLY POSSIBLE. HIGH CLOUDS HAVE ALREADY BEEN HAVING AN IMPACT ON MIXING THIS AFTERNOON...AND WITH THICKENING/LOWERING CLOUDS THOUGH THE NIGHT (ALONG WITH TD VALUES INCREASING TO MID/UPPER 30S IN THE EAST)...RADIATIONAL COOLING WILL BE LIMITED. NOT ONLY COULD THIS LIMIT DENSE FOG DEVELOPMENT...BUT THIS MAKES FREEZING FOG/FREEZING DRIZZLE UNLIKELY AT THIS POINT. AT THIS POINT HOLDING OFF ON HIGHLIGHTS SEEMS THE BEST COURSE. WITH SHIFT BACK TO SW FLOW AS SHORTWAVE RIDGING BUILDS BACK INTO THE ROCKIES THERE SHOULD BE RAPID IMPROVEMENT IN CONDITIONS SUNDAY.CLEARING SKIES AND WAA THROUGH THE AFTERNOON SHOULD ALLOW HIGHS TO WARM TO AROUND 60F...THOUGH STRATUS MAY HOLD ON A LITTLE LONGER IN OUR EASTERN CWA LIMITING DAYTIME MIXING AND KEEPING HIGHS IN THE LOW TO MID 50S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 207 PM MST SAT DEC 6 2014 UPPER FLOW WILL BE NORTHWEST SUNDAY NIGHT AHEAD OF A RIDGE THAT WILL BUILD INTO THE ROCKIES AND PLAINS MONDAY AND TUESDAY. SURFACE HIGH PRESSURE WILL RESIDE OVER THE PLAINS THROUGH THIS TIME. DRY CONDITIONS WILL CONTINUE ACROSS THE FA THROUGH TUESDAY. SUBSIDENCE AND OR A LACK OF SIGNIFICANT FORCING ALONG WITH A LACK OF LAYER MEAN RH WILL PROVIDE SUPPORT FOR THE DRY CONDITIONS. POPS WILL BE NIL FROM SUNDAY NIGHT THROUGH TUESDAY. MIN TEMPERATURES SHOULD BE IN THE MID AND UPPER 20S SUNDAY AND MONDAY NIGHTS. MAX TEMPERATURES SHOULD RISE TO THE MID 50S MONDAY AND TUESDAY. IN THE EXTENDED...(TUESDAY NIGHT THROUGH SATURDAY)... THIS PART OF THE FORECAST IS ALSO DRY. A RIDGE WILL RESIDE OVER THE PLAINS THROUGH THURSDAY AND THEN SHIFT EAST FRIDAY AND SATURDAY WITH FLOW BECOMING SOUTHWEST. SURFACE HIGH PRESSURE WILL CONTINUE OVER THE CENTRAL PLAINS THROUGH WEDNESDAY FOLLOWED BY A TROUGH IN EASTERN COLORADO FROM THURSDAY THROUGH SATURDAY. MAX TEMPERATURES WILL GENERALLY BE IN THE MID TO UPPER 50S WEDNESDAY AND SATURDAY. MAX TEMPERATURES THURSDAY AND FRIDAY SHOULD WARM TO THE UPPER 50S WITH LOWER 60S IN THE WESTERN FA. MIN TEMPERATURES SHOULD COOL TO THE UPPER 20S AND LOWER 30S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 400 PM MST SAT DEC 6 2014 KGLD...SOUTHEAST WIND AROUND 12KT AT TAF ISSUANCE WITH A SMALL WINDOW OF 15G23KTS FROM 02Z-05Z UNDER A VFR OVERCAST SKY. STRATUS/BR REACHES THE TERMINAL FROM THE EAST AROUND 06Z WITH IFR CIGS EXPECTED FROM 08Z-11Z WITH WINDS FROM THE SOUTH AROUND 10KTS. AROUND 12Z WINDS VEER TO THE SOUTHWEST 5-10KTS PUSHING THE STRATUS SLOWLY EAST ALLOWING FOR VFR CONDITIONS TO RETURN. WINDS THEN GO WEST 5-10KTS AROUND 15Z THEN NORTHWEST 13G21KT IN THE 18Z-22Z TIMEFRAME UNDER A FEW FAIR WEATHER CUMULUS CLOUDS. GUSTS DISSIPATE AROUND 23Z WITH A FEW HIGH CLOUDS POSSIBLE. KMCK...SOUTHEAST WIND 5-10KT AT TAF ISSUANCE UNDER A VFR OVERCAST SKY. STRATUS/DRIZZLE/BR WITH IFR CONDITIONS REACH THE TERMINAL FROM THE EAST AROUND 08Z AND CONTINUE THROUGH 17Z BEFORE WINDS VEER AROUND TO THE NORTHWEST NEAR 10KTS BY 18Z. THIS WILL SCOUR OUT THE STRATUS PRODUCING VFR CONDITIONS FROM 18Z THROUGH THE REST OF THE TAF PERIOD. IT SHOULD BE NOTED THAT IN THESE SCENARIOS THAT HIGH RESOLUTION MODELS OCCASIONALLY DONT PUSH THE STRATUS FAR ENOUGH WEST...BY AT LEAST ONE ROW OF COUNTIES. IF THIS VERIFIES STRATUS/BR (POSSIBLY FG WITH VLIFR CONDITIONS) MAY TAKE UP TO AN ADDITIONAL 3 HOURS TO MOVE OUT OF BOTH TERMINALS. WITH A THICK OVERCAST SKY HARD TO WATCH STRATUS PROGRESSION ON SATELLITE IMAGERY SO WILL HAVE TO WATCH METARS AND RUC/HRRR AND 00Z NAM MODEL DATA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...FS AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
208 PM MST SAT DEC 6 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 207 PM MST SAT DEC 6 2014 EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW PROGRESSIVE TROUGH-RIDGE TROUGH PATTERN ACROSS US WITH RIDGE CURRENTLY EXTENDING FROM SOUTH CENTRAL CANADA ACROSS THE CENTRAL PLAINS. SW FLOW IS IN PLACE FROM THE FOUR CORNERS REGION AND INTO WESTERN KS WITH SHORTWAVE TROUGH MOVING OUT OF THE GREAT BASIN TOWARDS THE CENTRAL ROCKIES. AT THE SURFACE LEE TROUGH IS IN PLACE OVER EASTERN COLORADO WITH SOUTHERLY FLOW ACROSS OUR CWA. AS SHORTWAVE TROUGH TRANSITIONS EASTWARD STATIONARY FRONT/BAROCLINIC ZONE WITH SHIFT NORTH AND EAST ALLOWING FOR SOUTHEAST MOISTURE RETURN INTO THE EASTERN HALF OF OUR CWA. MIDLEVEL MOISTURE/UPPER LEVEL FORCING COULD ALLOW FOR A BRIEF PERIOD OF LIGHT RAIN SHOWERS LATE TONIGHT...HOWEVER MODEL SOUNDINGS INDICATE A SIGNIFICANT DRY LAYER WOULD LIKELY PREVENT ANY ELEVATED PRECIPITATION FROM REACHING THE SURFACE. MAIN CONCERN WILL BE POTENTIAL FOR DENSE FOG DEVELOPMENT AND POTENTIAL FOR DRIZZLE ACROSS EASTERN CWA LATE TONIGHT THROUGH SUNDAY MORNING. NAM/RAP SHOW WEAK SURFACE CONVERGENCE IN PROXIMITY OF BAROCLINIC ZONE WHICH COULD PROVIDE ENOUGH LIFT WITHIN SHALLOW SATURATED LAYER TO ALLOW FOR DRIZZLE DEVELOPMENT. THIS COULD BE MORE OF A STRATUS/DRIZZLE EVENT...THOUGH CONSIDERING THE GOOD MOISTURE RETURN LOWER VISIBILITIES ARE CERTAINLY POSSIBLE. HIGH CLOUDS HAVE ALREADY BEEN HAVING AN IMPACT ON MIXING THIS AFTERNOON...AND WITH THICKENING/LOWERING CLOUDS THOUGH THE NIGHT (ALONG WITH TD VALUES INCREASING TO MID/UPPER 30S IN THE EAST)...RADIATIONAL COOLING WILL BE LIMITED. NOT ONLY COULD THIS LIMIT DENSE FOG DEVELOPMENT...BUT THIS MAKES FREEZING FOG/FREEZING DRIZZLE UNLIKELY AT THIS POINT. AT THIS POINT HOLDING OFF ON HIGHLIGHTS SEEMS THE BEST COURSE. WITH SHIFT BACK TO SW FLOW AS SHORTWAVE RIDGING BUILDS BACK INTO THE ROCKIES THERE SHOULD BE RAPID IMPROVEMENT IN CONDITIONS SUNDAY.CLEARING SKIES AND WAA THROUGH THE AFTERNOON SHOULD ALLOW HIGHS TO WARM TO AROUND 60F...THOUGH STRATUS MAY HOLD ON A LITTLE LONGER IN OUR EASTERN CWA LIMITING DAYTIME MIXING AND KEEPING HIGHS IN THE LOW TO MID 50S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 207 PM MST SAT DEC 6 2014 UPPER FLOW WILL BE NORTHWEST SUNDAY NIGHT AHEAD OF A RIDGE THAT WILL BUILD INTO THE ROCKIES AND PLAINS MONDAY AND TUESDAY. SURFACE HIGH PRESSURE WILL RESIDE OVER THE PLAINS THROUGH THIS TIME. DRY CONDITIONS WILL CONTINUE ACROSS THE FA THROUGH TUESDAY. SUBSIDENCE AND OR A LACK OF SIGNIFICANT FORCING ALONG WITH A LACK OF LAYER MEAN RH WILL PROVIDE SUPPORT FOR THE DRY CONDITIONS. POPS WILL BE NIL FROM SUNDAY NIGHT THROUGH TUESDAY. MIN TEMPERATURES SHOULD BE IN THE MID AND UPPER 20S SUNDAY AND MONDAY NIGHTS. MAX TEMPERATURES SHOULD RISE TO THE MID 50S MONDAY AND TUESDAY. IN THE EXTENDED...(TUESDAY NIGHT THROUGH SATURDAY)... THIS PART OF THE FORECAST IS ALSO DRY. A RIDGE WILL RESIDE OVER THE PLAINS THROUGH THURSDAY AND THEN SHIFT EAST FRIDAY AND SATURDAY WITH FLOW BECOMING SOUTHWEST. SURFACE HIGH PRESSURE WILL CONTINUE OVER THE CENTRAL PLAINS THROUGH WEDNESDAY FOLLOWED BY A TROUGH IN EASTERN COLORADO FROM THURSDAY THROUGH SATURDAY. MAX TEMPERATURES WILL GENERALLY BE IN THE MID TO UPPER 50S WEDNESDAY AND SATURDAY. MAX TEMPERATURES THURSDAY AND FRIDAY SHOULD WARM TO THE UPPER 50S WITH LOWER 60S IN THE WESTERN FA. MIN TEMPERATURES SHOULD COOL TO THE UPPER 20S AND LOWER 30S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1004 AM MST SAT DEC 6 2014 VFR CONDITIONS WILL PERSIST AT KGLD AND KMCK AT LEAST THROUGH 08Z. AFTER 08Z LOW LEVEL MOISTURE WILL BEGIN TO ADVECT NORTH AND EAST WITH LOW STRATUS...FOG...AND POSSIBLY DRIZZLE SPREADING INTO KMCK. KGLD LOOKS TO BE FAR ENOUGH WEST THAT CONDITIONS SHOULD REMAIN VFR THROUGH THE TAF PERIOD. IFR CIGS APPEAR LIKELY...HOWEVER THE CUTOFF OF POTENTIAL DENSE FOG/DRIZZLE IS DEPICTED VERY CLOSE TO KMCK TERMINAL. ITS TOO EARLY WITH LIMITED CONFIDENCE TO ADD LOWER CONDITIONS TO KMCK AT THIS POINT...BUT I PLAN ON KEEPING IFR CIG AND MVFR VIS GROUP IN THE 10-15Z PERIOD. GUSTY WINDS AT KGLD WILL DIMINISH AROUND SUNSET TODAY...WITH WINDS AT BOTH TERMINALS REMAINING BELOW 12KT THROUGH THE REST OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...FS AVIATION...DR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1156 AM EST SAT DEC 6 2014 .SYNOPSIS... CROSSING LOW PRESSURE WILL CONTINUE TO SPREAD RAIN ACROSS THE UPPER OHIO VALLEY REGION INTO THIS EVENING. HIGH PRESSURE WILL GIVE A DRY DAY SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... MID MORNING UPDATE TO SLOW TIMING FOR RAIN TO END BASED ON LATEST RADAR TRENDS AND INCOMING 12Z MODELS. STILL A CHANCE FOR SLEET TO MIX IN FAR NORTH THIS AFTERNOON BUT NOTHING OF CONSEQUENCE. HOURLY TEMPERATURES AND WINDS ADJUSTED TOWARD NEWEST LAMP GUIDANCE. WINDS WERE INCREASED ESPECIALLY THIS EVENING AS SURFACE LOW PUSHES EAST. PREVIOUS BELOW. ADDITIONAL BASIN AVG FORECAST RAINFALL WAS GENLY PROGGED AT APPROX A HALF TO THREE QUARTERS OF AN INCH USING SMOOTHED RFC GUIDANCE AND MORE REASONABLE RAP AND GFS ASCENT FIELDS...A HEALTHY AND PROLONGED RAINFALL THAT IS NOT EXPECTED TO CAUSE PROBLEMS. PASSAGE OF THE LOW WL INITIATE THE COLD FRONTAL INVASION LTR TDA AND INTO THE EVE. RESIDUAL RAIN WL THUS TURN TO SNOW LATE IN THE DAY...BUT RAPIDLY INCRSG SBSDNC/LOW INVERSION LVLS WL ENSURE A LACK OF ACCUMULATION POTENTIAL. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... RMNG SHWRS OF RAIN AND SNOW WL CONT TO DCRS IN COVERAGE THIS EVE. BLDG HIGH PRES THEREAFTER WL MAINTAIN DRY WEA UNTIL THE APCH OF THE NXT UPR TROF LATE ON MONDAY. SRN STREAM SHRTWV THROUGH THAT TROF IS CURRENTLY PROGGED TO SPIN UP A COASTAL LOW BY MONDAY...NEWD PROGRESS OF WHICH IS CURRENTLY PROGGED TO RMN SUFFICIENTLY E TO FOREGO PROBLEM CONTRIBUTION FOR THE UPR OH REGION. NEVERTHELESS...PCPN CHCS WL INCRS ON MON NGT INTO TUESDAY AS ISENTROPIC LIFT...WARM MOIST ADVCTN DVLPS ON THE ERN FLANKS OF THE HIGH AMPLITUDE ERN CONUS TROF. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A DEEP ERN CONUS TROF IS PROGGED TO PERSIST THRU ERLY INTO THE WKEND AS COASTAL SFC LOW PRES TRACKS UP THE E COAST. FCST SNW SHWR CHCS INTO WED NGT UNTIL THE LOW AND UPR SPPRT EXITS THE RGN. A WK SRTWV IS PROGGED TO ROTATE THRU THE GT LKS ARND THE MAIN TROF FRI THOUGH WITH BLDG SFC HIGH PRES UNDER THE TROF KEPT A DRY FCST. BLO SEASONAL TEMPS SHOULD RTN TO NR AVG BY LT WK. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... LATEST OBSERVATIONS BEGINNING TO SHOW IFR CONDITIONS IMPROVING TO MVFR ACROSS WESTERN OHIO WHERE WINDS ALOFT VEER TO THE WEST/NORTHWEST BEHIND THE AXIS OF THE MID-LEVEL TROUGH PASSING ACROSS THE REGION. WINDS WILL INCREASE AND BE GUSTY THROUGH MID AFTERNOON AS THE TROUGH PASSES THROUGH AND THE BOUNDARY LAYER DEEPENS...TAPPING STRONGER WINDS ALOFT. WINDS GUSTS WILL RANGE BETWEEN 15 AND 20KTS ON AVERAGE. MID AND UPPER LEVELS WILL QUICKLY DRY OUT BEHIND THE TROUGH CLEARING OUT MID AND UPPER LEVEL CLOUDS FROM WEST TO EAST STARTING LATER THIS AFTERNOON. THIS TREND WILL CONTINUE TONIGHT AS HIGH PRESSURE BUILDS IN...WITH DRY CONDITIONS AND LIMITED CLOUD COVERAGE EXPECTED ON SUNDAY. OUTLOOK.../SUNDAY THROUGH WEDNESDAY/... RESTRICTIONS ARE ANTICIPATED ON TUESDAY AS THE NEXT FRONTAL SYSTEM TRANSITIONS OVER THE AREA. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
314 PM CST Sat Dec 6 2014 .SHORT TERM: (Through Late Tonight) Issued at 300 PM CST Sat Dec 6 2014 Low stratus located within the southern portion of a large high pressure system continues to dominate the region at mid afternoon. There has been a slow clearing trend to our north with the clearing line located near the MO/IA border into northern IL. This high pressure system will dominate tonight as it moves to the east with low level flow gradually veering to easterly by mid evening and then east-southeasterly overnight. Given the trends in the wind field, there will probably be additional southward clearing into the early evening then the northern edge will hold steady before retreating back northwest overnight. The RAP H950 RH is the only guidance that seems to have a decent handle on this evolution. The abundance of clouds tonight would suggest MOS guadance is too low on mins, with the coolest values expected across northeast MO and west central IL. Glass .LONG TERM: (Sunday through Next Saturday) Issued at 300 PM CST Sat Dec 6 2014 The high pressure system will continue to retreat on Sunday and this will keep low clouds prevalent. Add in high clouds and it will make for a mostly cloudy-cloudy day. There are some indications that southern portions of the CWA could see some clearing from the south of the low clouds, and hence warmer high temps are expected. The next threat of precipitation will come Sunday night into Monday morning. A short wave trof will dig into the mid-upper MS valley. The large scale ascent associated with this wave along increasing mid level moisture and low level warm advection should be sufficient to generate some spotty/scattered precipitation ahead of the attendant cold front. Temperature profiles indicate the precipitation should be in the form of rain, with the highest pops late Monday night across northeast MO and along and east of the MS River on Monday morning. Monday should be milder with decreasing clouds as first a prefrontal trof and then the cold front then sweeps through the area. Another brief round of cold air then dominates on Tuesday with expansive high pressure. The upper air pattern will be in transition during the extended period from Wednesday into next weekend. The eastern U.S. upper trof/low will be progressive lifting northeast and eventually off the Atlantic Seaboard. A northwest flow short wave in the wake of the slowly retreating trof looks to impact our area sometime late Wednesday into early Thursday, however present indications are any precipitation threat should be confined to western MO. Heights aloft then gradually rise in the wake of the shortwave trof and high pressure departs, leading to southerly low level flow Friday into the Saturday and a warming trend. Glass && .AVIATION: (For the 18z TAFs through 18z Sunday Afternoon) Issued at 1147 AM CST Sat Dec 6 2014 Should see slow improvement in visibilities this afternoon but only a slight gradual rise in ceiling heights, except at UIN where the southward advancing clearing line across southern IA and northwestern IL may make it to by late afternoon or early evening. Elsewhere ceiling heights will likely only improve to around 1000 feet late this afternoon, then drop some late tonight along with the redevelopment of at least light fog. Status clouds will likely redevelop or advect back into UIN late tonight as the surface/low level flow becomes easterly. For now will keep it scattered in the UIN TAF tonight, but this may be too optimistic. There should be more substantial improvement in the ceiling heights at the other taf sites by late Sunday morning, possibly into the MVFR catagory. Nly surface wind will gradually veer around to an ely direction tonight, and a sely direction Sunday morning as the surface ridge extending from MN southwest into the TX panhandle moves eastward through our area. Specifics for KSTL: The visibilities should become unrestricted by late afternoon, but the ceiling height may only rise to around 1000 feet. The ceiling height may lower some late tonight along with the redevelopment of at least light fog. Should see more improvement on Sunday, possibly going VFR in the afternoon. Nly surface wind will veer around to a nely direction this evening, then to a sely direction by late Sunday morning. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
333 PM CST SAT DEC 6 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 333 PM CST SAT DEC 6 2014 THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE POSSIBLE FREEZING PRECIPITATION TONIGHT AND SUNDAY. CURRENTLY A SHORTWAVE TROUGH IS LOCATED OVER EASTERN WASHINGTON. THE WAVE WILL TRACK ALONG THE INTERNATIONAL BORDER OVERNIGHT AND DEVELOP A SURFACE LOW IN THE LEE OF THE ROCKIES. THE SURFACE/UPPER LEVEL LOW IS PROGGED TO BE OVER NORTHEAST MT/SOUTH CENTRAL SK BY 12 UTC SUNDAY. WARM ADVECTION AHEAD OF THE LOW WILL RESULT IN WARM TEMPERATURES ALOFT ENCOMPASSING ALL OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT. THUS THE POTENTIAL FOR FREEZING PRECIPITATION THROUGH SUNDAY AFTERNOON. THE LATEST 20 UTC RAP DEPICTS A BAND OF LIGHT REFLECTIVITIES MOVING INTO WESTERN NORTH DAKOTA AROUND 08 UTC SUNDAY. HOWEVER...ANY MEASURABLE PRECIPITATION REMAINS CONFINED TO THE FAR NORTHWEST CORNER OF NORTH DAKOTA. THE RAP MAINTAINS THE LIGHT REFLECTIVITIES AS THEY CROSS THE CWA BUT KEEPS MAINLY TRACE AMOUNTS...AND MAINLY CONFINED TO THE FAR NORTHERN TIER COUNTIES. THE GFS/EC/GEM ALL BRING VERY LIGHT QPF INTO THE FAR NORTHWEST THROUGH 12 UTC. THE EC/GEM ALSO TRACK SOME TRACE AMOUNTS ALONG THE NORTHERN TIER COUNTIES THROUGH THE MORNING. THE GFS IS FARTHER SOUTH AND IS ON THE SOUTHERN SIDE OF THE ENVELOPE OF DETERMINISTIC SOLUTIONS. THUS HAVE KEPT BEST CHANCE FOR QPF IN THE FAR NORTHWEST 06-12 UTC SUNDAY AND ACROSS THE FAR NORTHERN TIER COUNTIES 12-18 UTC SUNDAY. WILL STILL HAVE A MENTION OF SOME FREEZING RAIN SOUTHWEST AND SOUTH CENTRAL (MAINLY ALONG AND NORTH OF I-94) BUT WITH NO SIGNIFICANT ACCUMULATIONS. EVEN ACROSS THE NORTH...DETERMINISTIC MODEL QPF REMAINS AT OR BELOW A HUNDREDTH OF AN INCH. ONLY A LITTLE FREEZING RAIN CAN CAUSE SIGNIFICANT TRAVEL ISSUES. BUT WITH LOW MODEL QPF...WILL HOLD OFF ON ANY HIGHLIGHTS AT THIS TIME. WE WILL STILL HAVE TIME TO WATCH THINGS DEVELOP ACROSS NORTHEAST MONTANA AND SOUTHERN SASKATCHEWAN THIS EVENING AND OVERNIGHT. COULD STILL SEE A VERY LIGHT MIX OVER THE NORTH CENTRAL MONDAY AFTERNOON. BUT WESTERN NORTH DAKOTA WILL BE ON THE BACK SIDE OF THE MID LEVEL TROUGH WITH COLD ADVECTION TRACKING SOUTHEAST ACROSS THE CWA DURING THE AFTERNOON. THUS THE WEST WILL QUICKLY TRANSITION TO SNOW AND THE SOUTH CENTRAL SHOULD WARM UP ENOUGH TO SEE ALL RAIN WITH A QUICK CHANGE TO SNOW AS THE COLD ADVECTION ARRIVES. IT WILL ALSO BECOME BREEZY TO WINDY SUNDAY AFTERNOON FROM WEST TO EAST BEHIND THE TRACK OF THE LOW. STRONGEST WINDS 20-30 MPH WITH GUSTS TO 35 MPH WILL SPREAD FROM THE SOUTHWEST SUNDAY AFTERNOON INTO THE CENTRAL LATE AFTERNOON TO EARLY EVENING. HIGHS SUNDAY WILL LIKELY BE REACHED IN THE MORNING NORTH TO EARLY AFTERNOON SOUTH WITH TEMPERATURES FALLING MID TO LATE AFTERNOON EVERYWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 333 PM CST SAT DEC 6 2014 POST FRONTAL NORTHWEST WINDS OF 20 TO 30 MPH ALONG WITH ISOLATED TO SCATTERED SNOW SHOWERS WILL DOMINATE SUNDAY NIGHT. THE ENTIRE SYSTEM DEPARTS CENTRAL NORTH DAKOTA BY 12Z MONDAY WITH COLDER AIR REMAINING IN PLACE FOR THE MORNING FOLLOWED BY WARM AIR ADVECTION MONDAY AFTERNOON ESPECIALLY IN THE WEST. A PROGRESSIVE PATTERN CONTINUES WITH A TRANSITORY RIDGE SHIFTING THROUGH MONDAY NIGHT FOLLOWED BY A DRY SHORTWAVE TROUGH PASSING THROUGH TUESDAY. THEREAFTER...UPPER RIDGING DOMINATES AND SHIFTS EAST BY MIDWEEK ALLOWING A SOUTHWEST FLOW TO RETURN. HOWEVER NOTHING FORESEEN IN THE SOUTHWEST FLOW IN TERMS OF SIGNIFICANT SHORTWAVES AT LEAST THROUGH SATURDAY PER GFS/GEM GLOBAL/SUPERBLEND. HOWEVER THE LATEST ECMWF PUSHES A FAST MOVING SHORTWAVE AND CONSEQUENTLY LIGHT PRECIPITATION/FAVORING RAIN SHOWERS AT THIS POINT...ACROSS THE NORTH THURSDAY. HIGH TEMPERATURES WILL WARM TO BETWEEN 35F AND 45F WEDNESDAY THROUGH FRIDAY...THEN A BIT COOLER FOR SATURDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 333 PM CST SAT DEC 6 2014 VFR CONDITIONS THIS AFTERNOON AND TONIGHT. A LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA BY SUNDAY MORNING. COULD SEE A VERY BRIEF PERIOD OF FREEZING RAIN AHEAD OF THE SYSTEM. ALTHOUGH WITH ONLY SLIGHT CHANCES...WILL NOT ADD THE FZRA TO THE TAFS. SUNDAY WINDS WILL SHIFT WEST TO NORTHWEST AND INCREASE...WITH INCREASING MVFR CLOUDS AND A CHANCE OF SNOW SHOWERS...BUT MAINLY AFTER 18 UTC. WILL BRING A SCATTERED MVFR LAYER INTO THE WEST AND NORTH LATE IN THE FORECAST PERIOD. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...TWH LONG TERM...KS AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1249 PM CST SAT DEC 6 2014 .UPDATE... ISSUED AT 1249 PM CST SAT DEC 6 2014 CLOUDS CONTINUE OVER MUCH OF THE REGION...WITH THE WESTERN EDGE OF THE DECK NOT MOVING INTO OUR CWA UNTIL LATE AFTERNOON. MADE ONLY A FEW MINOR TWEAKS TO CLOUDS. THERE CONTINUE TO BE A FEW RADAR RETURNS OVER THE REGION...BUT NOTHING IS REACHING THE GROUND AND ONLY MID LEVEL CLOUDS HAVE BEEN REPORTED. WILL LET FLURRY MENTION GO AWAY FOR THE AFTERNOON AS PLANNED. WILL CONTINUE TO KEEP TEMPS CLIMBING INTO THE 20S AS EVEN WITH CLOUDS WE ARE UPPER TEENS TO LOW 20S AT THE CURRENT HOUR. UPDATE ISSUED AT 950 AM CST SAT DEC 6 2014 CLOUDS CONTINUE TO SPREAD ACROSS THE CWA AS SEEN ON SATELLITE AND WEB CAMS...SO INCREASED CLOUD COVER FOR MUCH OF THE DAY. WE COULD START SEEING SOME BREAKS IN THE WEST LATE AS THE EDGE OF THE CLOUD DECK APPROACHES. THERE HAS BEEN A FEW FLURRIES REPORTED NEAR THE WESTERN CWA BORDER SO INCLUDED AN ISOLATED MENTION THROUGH THE NEXT FEW HOURS. LOWERED HIGHS A DEGREE OR SO WITH INCREASED CLOUDS...BUT STILL THINK WE SHOULD GET INTO THE 20S. UPDATE ISSUED AT 655 AM CST SAT DEC 6 2014 THERE HAS BEEN PATCHY DENSE FOG DEVELOP OVER THE PAST FEW HOURS...BUT QUICKLY DISSIPATE ONCE MID-HIGH CLOUDS COME OVERHEAD. THE ONLY UPDATE IS FOR THE SKY GRID TO ACCOUNT FOR MID-LEVEL CLOUDS SPREADING OVER THE REGION A BIT FASTER THAN ANTICIPATED (FOLLOWED THE RAP 700MB RH FIELD). && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 FREEZING RAIN POTENTIAL ON SUNDAY WILL BE THE MAIN CONCERN FOR THIS PERIOD. 00Z MODELS IN DECENT AGREEMENT...ALTHOUGH DIFFERENCES IN THERMAL PROFILES WILL MAKE FOR A CHALLENGING FORECAST. HIGH PRESSURE PROPAGATES ACROSS THE REGION TODAY WITH SOUTHERLY RETURN FLOW SETTING UP THIS AFTERNOON. SATELLITE IMAGERY AND OBSERVATIONS INDICATE PATCHY FOG DEVELOPING...AND WILL NEED TO MONITOR (DID INCLUDE PATCHY FOG IN THE FORECAST FOR SOME LOCATIONS). WEAK SYSTEM WILL BE PROPAGATING ACROSS SOUTHERN CANADA TODAY...AND ALTHOUGH THE STRONGEST FORCING WILL BE NORTH OF THE INTERNATIONAL BORDER...DO EXPECT AN AREA OF CLOUDS TO MOVE THROUGH THE REGION. THE TEMPERATURE FORECAST IS A BIT TRICKY. MOST AREAS SHOULD BE ABLE TO RISE INTO THE 20S THIS AFTERNOON...THEN AFTER A BRIEF DIP IN VALUES...STRONGER WARM AIR ADVECTION COMMENCES TONIGHT AND ANTICIPATE SLOWLY RISING VALUES. MAJORITY OF MODEL GUIDANCE IS INDICATING A STRONGER SIGNAL FOR FREEZING RAIN SUNDAY MORNING...ESPECIALLY THE SOUTHERN VALLEY INTO WEST CENTRAL MINNESOTA AND PORTIONS OF NORTHWEST MINNESOTA (MAINLY ALONG AND EAST OF A LINE FROM WAHPETON TO BAUDETTE). QPF AMOUNTS LIKELY AROUND 0.10 INCHES. THE GENERAL IDEA IS THAT EVAPORATIVE COOLING WILL TRANSITION A FREEZING RAIN/SLEET MIX TO SNOW...BUT GIVEN THE SREF P-TYPE PROBABILITIES (VERY HIGH FREEZING RAIN PROBABILITIES)...THE THOUGHT IS THAT THE OPERATIONAL MODELS MAY BE EVAPORATIVELY COOLING TOO QUICKLY (WHICH DOES HAPPEN) AND/OR TOO DRY ALOFT. IF CONFIDENCE INCREASES IN THE EXPECTED THERMAL PROFILE...ALONG WITH SFC TEMPERATURES REMAINING BELOW FREEZING...SOME SORT OF ADVISORY MAY BE NEEDED FOR THIS AREA. OTHERWISE...AREAS TO THE WEST WILL LIKELY BE WELL INTO THE 30S ON SUNDAY AND MOSTLY DRY. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 400 AM CST SAT DEC 6 2014 SUNDAY NIGHT-MONDAY NIGHT...DEFORMATION ZONE SNOW SHOWERS SUNDAY NIGHT INTO THE EARLY PORTIONS OF MONDAY AS THE SYSTEM FROM THE SHORT TERM PERIOD MOVES AWAY FROM THE REGION. HIGH PRESSURE BUILDS INTO THE REGION BY LATER MONDAY. ANTICIPATE A COLDER AIRMASS WITH TEMPERATURES NEAR NORMAL (THE HIGHS ON MONDAY MAY OCCUR IN THE MORNING). TUESDAY-FRIDAY...EXTENDED PERIOD BEGINS UNDER NORTHWEST FLOW AND NEAR AVERAGE TEMPERATURES FOR THE FIRST HALF OF DECEMBER. AFTERWARDS GUIDANCE DIFFERS ON TIMING AND PLACEMENT OF SHORT WAVE ENERGY RIDING THROUGH UPPER RIDGE DURING THE MIDDLE OF THE WEEK. ECMWF PREFERS TO KEEP WAVE OVER SOUTHERN CANADA WHILE GFS IS FARTHER SOUTH CLOSER TO THE NORTHERN/CENTRAL PLAINS INTERFACE. GFS IS TYPICALLY A BIT FASTER WITH THIS FEATURE AND THE WEAK SHORT WAVE IS NOT EXPECTED TO HAVE A GREAT IMPACT ON FORECAST. THE EARLY PERIOD AVERAGE TEMPERATURES WILL BEGIN TO WARM FROM WEDNESDAY THROUGH FRIDAY AS RETURN FLOW/WARM ADVECTION INCREASES WITH A SHORT WAVE RIDGE BUILDING INTO THE FORECAST AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1249 PM CST SAT DEC 6 2014 MID-LEVEL VFR CLOUD DECK IN THE 5-8 KFT RANGE WILL CLEAR FROM WEST TO EAST LATE THIS AFTERNOON AND EVENING...WITH HIGH CIRRUS STREAMING IN FROM THE WEST BY LATE TODAY. AS SFC LOW PRESSURE TO THE WEST APPROACHES...SOUTH/SOUTHEAST WINDS WILL STRENGTHEN THIS EVENING...PERHAPS A BIT GUSTY AT TIMES...DESPITE SHALLOW VERTICAL MIXING. MOISTURE WILL SPREAD NORTHWARD BY EARLY SUNDAY...LIKELY SPREADING LOW CLOUDS INTO THE REGION. FOR NOW TRENDED TO MVFR...BUT BASED ON CURRENT OBS TO THE SOUTH AND MODEL GUIDANCE...IFR CONDITIONS CERTAINLY A GOOD POSSIBILITY WITH PERHAPS SOME REDUCED VSBYS AS WELL. EXACT TIMING OF ARRIVAL OF THE LOWER CEILINGS AT EACH SITE REMAINS SOMEWHAT UNCERTAIN. SOME LIGHT SLEET/FZRA MAY AFFECT ESPECIALLY KBJI BY LATE IN THE TAF PERIOD...WITH LOWER CONFIDENCE IN PRECIP WESTWARD AT KFAR...KTVF...AND KGFK. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...TG LONG TERM...WJB/TG AVIATION...MAKOWSKI
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
316 PM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE WAVE PASSES WITH COLDER AIR IN ITS WAKE TONIGHT. HIGH PRESSURE SUNDAY. UPPER TROUGH MONDAY NIGHT/TUESDAY. COLDER AIR TUESDAY NIGHT INTO WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... AS OF 18Z THE FRONT HAS CLEARED CRW AND CKB WITH SURFACE LOW E OF EKN. FRONT WILL CLEAR THE MOUNTAINS BY 21Z. AS THE FRONT CROSSES...TEMPERATURE FALLS OF 7 TO 10 DEGREES CAN BE EXPECTED WITH GRADUALLY LOWERING TEMPS THEREAFTER THROUGH THE EVENING. LOW CIGS AND VSBY IN POST FRONTAL DZ CAN BE EXPECTED THRU THE REMAINDER OF THE AFTERNOON...ALONG WITH GUSTY NW WINDS. WILL WATCH -RA TO FILL BACK IN LATER THIS AFTERNOON AS THE UPPER LEVEL TROF CROSSES. AREA WILL BEGIN TO DRY OUT WITH PASSAGE OF THE UPPER LEVEL TROF...SAVE FOR SOME DZ HANGING ON ACROSS THE MOUNTAINS THIS EVENING. ELECTED TO KEEP POSSIBILITY OF IT ENDING AS A LITTLE FRZ DZ BUT NOT EXPECTING ANY IMPACTS. WHAT WILL NOT CLEAR OUT THIS EVENING IS THE LOW STRATUS. HOWEVER...DO EXPECT BASES TO LIFT A BIT TONIGHT. THINK SE OH WILL SCT OUT DURING THE PREDAWN. HOWEVER...DEVELOPING SUBSIDENCE INVERSION BENEATH THIS LINGERING MOISTURE WILL MAKE IT VERY DIFFICULT FOR STRATUS TO BREAK UP E OF THE OH RIVER OVERNIGHT. WITH WEAK CAA BENEATH THE INVERSION AND LOW LEVEL WINDS BECOMING MORE NE...FELT IT NECESSARY TO HOLD THE STRATUS IN ALONG THE CLIMATOLOGICAL FAVORED AREAS IN THIS SETUP....IE THE C LOWLANDS AND COAL FIELDS THRU THE MORNING HOURS. CLOUDS WILL GRADUALLY SCT OUT FROM NE TO SW...WITH AREAS ALONG AND S OF I64 CORRIDOR THE LAST TO LOSE THE STRATUS...POSSIBLY HOLDING ON UNTIL LATE AFTERNOON. FOR TEMPS...USED A BLEND OF LAMP AND HRRR FOR TEMPS TONIGHT. FOR SUNDAY...USED MET AS A BASE WHICH BETTER REFLECTED EXPECTED COOLER READINGS ALONG AND ESPECIALLY S OF I64 CORRIDOR DUE TO CLOUDS. FURTHER N...FELT LOCAL MOS WAS THE WAY TO GO WHERE READINGS SHOULD REACH INTO THE MID OR UPPER 40S. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... STRONG MID LEVEL RIDGING AND HIGH PRESSURE INFLUENCES FROM EASTERN CANADA DOMINATE SUNDAY...BUT SUNSHINE STILL LIMITED TO THE MORNING HOURS WITH CIRRUS AHEAD OF THE UPPER LEVEL TROUGH DIGGING IN OVER THE WESTERN GREAT LAKES. MODELS NOW SETTLING ON THE TROUGH AXIS HOLDING THE DEVELOPING COASTAL SYSTEM OFFSHORE AND MAINLY AWAY FROM OUR EASTERN MOST RIDGES...BUT WILL STILL ENTERTAIN SOME LOW END POPS FOR THE FAR EASTERN PORTIONS OF RAND/POCA COUNTIES. SOME ICING IS POSSIBLE IN THE SOUTHEAST UPSLOPE AREAS. HAVE THE TRANSITION TO SNOW FOR THE LOWLAND UPSLOPE AREAS FROM RAIN TO SNOW A BIT SLOWER...AND JUST BEGINNING BY THE END OF THE SHORT TERM FORECAST AT 00Z WEDNESDAY. 925MB TEMPERATURES GO BELOW 0C JUST AFTER 21Z TUESDAY FOR THE MOUNTAINS...MAKING THE 18Z TO 00Z PERIOD THE RAIN/SNOW TRANSITION TIMES FOR THE MOUNTAINOUS AREAS. LOWLANDS WILL TRANSITION TO SNOW LIKELY IN THE BEGINNING FEW HOURS OF THE LONG TERM. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... USED A BLEND OF THE GFS...GEFS MEAN...ECMWF...ECMWF MEAN...AND CONTINUITY WITH THE PREVIOUS FORECAST. THIS WOULD HAVE WRAP AROUND MOISTURE OVER THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. 850 MB TEMPERATURES ARE MARGINAL FOR UPSLOPE SNOW...SO COULD SEE DRIZZLE INSTEAD OF SNOW IN MANY AREAS. A HIGH PRESSURE SYSTEM THEN MOVES IN FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND...ALLOWING TEMPERATURES TO MODERATE SOME. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... SURFACE FRONT WAS E OF CRW/CKB AS OF 18Z. EXPECT IT TO CROSS KEKN AND KBKW BY 20Z. CIGS AND VSBY WILL LOWER INTO IFR OR WORSE FOR A TIME IN POST FRONTAL DZ ACROSS MUCH OF THE AREA. WINDS WILL ALSO GUST IN THE 15 TO 20 KT RANGE...A BIT HIGHER WITH ACTUAL FROPA. ANOTHER ROUND OF SHRA POSSIBLE LATER THIS AFTERNOON AND INTO THE EARLY EVENING HRS WITH THE PASSAGE OF THE UPPER LEVEL TROF. ALLOWED TO VSBY TO IMPROVE INTO MVFR AND EVENTUAL VFR OVERNIGHT AS DRIER AIR ADVECTS IN NEAR THE SURFACE. ALSO ALLOWED CIGS TO LIFT A BIT INTO MVFR...FOLLOWING PASSAGE OF THE UPPER TROF. STILL HAVE CIGS BELOW 2 GRAND MARK THOUGH. THE LOW STRATUS SHOULD SCT OUT ACROSS SE OH OVERNIGHT...BUT WILL HANG TOUGH E OF THE OH RIVER TO AFFECT THE TAF SITES. THE LOW LEVEL FLOW WILL BECOME MORE NE OVERNIGHT WITH SOME GUSTS CONTINUING. THIS COMBINED WITH DEVELOPING SUBSIDENCE INVERSION WILL KEEP THE LOW STRATUS IN PLACE FIRST HALF OF SUNDAY...WITH KCRW AND KHTS PERHAPS NOT SCT OUT UNTIL AFTER END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS MAY VARY. TIMING ERADICATION OF LOW STRATUS MAY VARY...POSSIBLY OCCURRING MUCH SOONER THAN CURRENTLY FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H M M H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H M M L L L L H H M EKN CONSISTENCY H L L L L L L L L L L M PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H M M H H H H H M M M M AFTER 18Z SUNDAY... IFR POSSIBLE IN RAIN/SNOW MONDAY NIGHT INTO WEDNESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...RPY/30/26 NEAR TERM...30 SHORT TERM...26 LONG TERM...RPY AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
149 PM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE WAVE PASSES WITH COLDER AIR IN ITS WAKE TONIGHT. HIGH PRESSURE SUNDAY. LOW PRESSURE ALONG MID ATLANTIC COAST MONDAY NIGHT. COLD FRONT TUESDAY WITH COLDER AIR TUESDAY NIGHT INTO WEDNESDAY. && .NEAR TERM /THROUGH SUNDAY/... AS OF 18Z THE FRONT HAS CLEARED CRW AND CKB WITH SURFACE LOW E OF EKN. FRONT WILL CLEAR THE MOUNTAINS BY 21Z. AS THE FRONT CROSSES...TEMPERATURE FALLS OF 7 TO 10 DEGREES CAN BE EXPECTED WITH GRADUALLY LOWERING TEMPS THEREAFTER THROUGH THE EVENING. LOW CIGS AND VSBY IN POST FRONTAL DZ CAN BE EXPECTED THRU THE REMAINDER OF THE AFTERNOON...ALONG WITH GUSTY NW WINDS. WILL WATCH -RA TO FILL BACK IN LATER THIS AFTERNOON AS THE UPPER LEVEL TROF CROSSES. AREA WILL BEGIN TO DRY OUT WITH PASSAGE OF THE UPPER LEVEL TROF...SAVE FOR SOME DZ HANGING ON ACROSS THE MOUNTAINS THIS EVENING. ELECTED TO KEEP POSSIBILITY OF IT ENDING AS A LITTLE FRZ DZ BUT NOT EXPECTING ANY IMPACTS. WHAT WILL NOT CLEAR OUT THIS EVENING IS THE LOW STRATUS. HOWEVER...DO EXPECT BASES TO LIFT A BIT TONIGHT. THINK SE OH WILL SCT OUT DURING THE PREDAWN. HOWEVER...DEVELOPING SUBSIDENCE INVERSION BENEATH THIS LINGERING MOISTURE WILL MAKE IT VERY DIFFICULT FOR STRATUS TO BREAK UP E OF THE OH RIVER OVERNIGHT. WITH WEAK CAA BENEATH THE INVERSION AND LOW LEVEL WINDS BECOMING MORE NE...FELT IT NECESSARY TO HOLD THE STRATUS IN ALONG THE CLIMATOLOGICAL FAVORED AREAS IN THIS SETUP....IE THE C LOWLANDS AND COAL FIELDS THRU THE MORNING HOURS. CLOUDS WILL GRADUALLY SCT OUT FROM NE TO SW...WITH AREAS ALONG AND S OF I64 CORRIDOR THE LAST TO LOSE THE STRATUS...POSSIBLY HOLDING ON UNTIL LATE AFTERNOON. FOR TEMPS...USED A BLEND OF LAMP AND HRRR FOR TEMPS TONIGHT. FOR SUNDAY...USED MET AS A BASE WHICH BETTER REFLECTED EXPECTED COOLER READINGS ALONG AND ESPECIALLY S OF I64 CORRIDOR DUE TO CLOUDS. FURTHER N...FELT LOCAL MOS WAS THE WAY TO GO WHERE READINGS SHOULD REACH INTO THE MID OR UPPER 40S. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... STILL A TOUGH CLOUD AND TEMPERATURE FORECAST FOR SUNDAY...WITH LOW LEVEL MOISTURE MOSTLY AOB 925 MB SUNDAY MORNING. WILL HOLD ONTO THOSE CLOUDS A BIT LONGER IN SOUTHERN COAL FIELDS OF WV. SURFACE HIGH PRESSURE QUICKLY PASSES OUR LONGITUDE SUNDAY AFTERNOON WITH LOW LEVEL FLOW VEERING TO EAST AND SOUTHEAST SUNDAY NIGHT. ANOTHER TOUGH TEMPERATURE FORECAST WITH 925 MB FLOW BLOWING AT 15 TO 25 KNOTS. SOME HIGH CLOUDS MAY ALSO BE AROUND SUNDAY NIGHT. WILL TRY TO DROP TEMPERATURES A BIT LOWER...BUT NOT AS LOW AS NAM AND GFS MOS GUIDANCE. THE SURFACE WAVE ALONG THE MID ATLANTIC COAST...TRYING TO GET ORGANIZED MONDAY INTO MONDAY NIGHT...MAY BRUSH OUR EASTERN MOUNTAIN COUNTIES WITH DEEPER MOISTURE...BUT CURRENTLY WILL ONLY HAVE CHANCE POPS THERE....BEFORE THAT DEEPER MOISTURE GETS SHUNTED EAST. THE EASTERN LOW LEVEL FLOW SHOULD KEEP THOSE UPSLOPE AREAS A BIT COOLER FOR MONDAY MAXIMUM TEMPERATURE. THE WESTERN THE DIGGING UPPER/MID LEVEL TROUGH FROM THE UPPER MIDWEST STARTS AFFECTING US TUESDAY WITH COLDER AIR BECOMING ESTABLISHED BY TUESDAY NIGHT. INCREASED POPS FOR SNOW SHOWERS...ESPECIALLY FOR TUESDAY NIGHT. OVERALL...NO MAJOR STORMS FORESEEN...BUT A COLDER PATTERN BY TUESDAY INTO WEDNESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... USED A BLEND OF THE GFS...GEFS MEAN...ECMWF...ECMWF MEAN...AND CONTINUITY WITH THE PREVIOUS FORECAST. THIS WOULD HAVE WRAP AROUND MOISTURE OVER THE REGION FOR TUESDAY NIGHT INTO WEDNESDAY. 850 MB TEMPERATURES ARE MARGINAL FOR UPSLOPE SNOW...SO COULD SEE DRIZZLE INSTEAD OF SNOW IN MANY AREAS. A HIGH PRESSURE SYSTEM THEN MOVES IN FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND...ALLOWING TEMPERATURES TO MODERATE SOME. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... SURFACE FRONT WAS E OF CRW/CKB AS OF 18Z. EXPECT IT TO CROSS KEKN AND KBKW BY 20Z. CIGS AND VSBY WILL LOWER INTO IFR OR WORSE FOR A TIME IN POST FRONTAL DZ ACROSS MUCH OF THE AREA. WINDS WILL ALSO GUST IN THE 15 TO 20 KT RANGE...A BIT HIGHER WITH ACTUAL FROPA. ANOTHER ROUND OF SHRA POSSIBLE LATER THIS AFTERNOON AND INTO THE EARLY EVENING HRS WITH THE PASSAGE OF THE UPPER LEVEL TROF. ALLOWED TO VSBY TO IMPROVE INTO MVFR AND EVENTUAL VFR OVERNIGHT AS DRIER AIR ADVECTS IN NEAR THE SURFACE. ALSO ALLOWED CIGS TO LIFT A BIT INTO MVFR...FOLLOWING PASSAGE OF THE UPPER TROF. STILL HAVE CIGS BELOW 2 GRAND MARK THOUGH. THE LOW STRATUS SHOULD SCT OUT ACROSS SE OH OVERNIGHT...BUT WILL HANG TOUGH E OF THE OH RIVER TO AFFECT THE TAF SITES. THE LOW LEVEL FLOW WILL BECOME MORE NE OVERNIGHT WITH SOME GUSTS CONTINUING. THIS COMBINED WITH DEVELOPING SUBSIDENCE INVERSION WILL KEEP THE LOW STRATUS IN PLACE FIRST HALF OF SUNDAY...WITH KCRW AND KHTS PERHAPS NOT SCT OUT UNTIL AFTER END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS MAY VARY. TIMING ERADICATION OF LOW STRATUS MAY VARY...POSSIBLY OCCURRING MUCH SOONER THAN CURRENTLY FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M M H H H H H H H H H H BKW CONSISTENCY H H H H H M M L L L L H EKN CONSISTENCY H H H L L L L L L L L L PKB CONSISTENCY H M H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SUNDAY... IFR POSSIBLE IN RAIN/SNOW MONDAY NIGHT INTO WEDNESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...RPY/30/26 NEAR TERM...30 SHORT TERM...KTB LONG TERM...RPY AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
147 PM EST SAT DEC 6 2014 .SYNOPSIS... LOW PRESSURE WAVE PASSES WITH COLDER AIR IN ITS WAKE TONIGHT. HIGH PRESSURE SUNDAY. LOW PRESSURE ALONG MID ATLANTIC COAST MONDAY NIGHT. COLD FRONT TUESDAY WITH COLDER AIR TUESDAY NIGHT. && .NEAR TERM /THROUGH SUNDAY/... AS OF 18Z THE FRONT HAS CLEARED CRW AND CKB WITH SURFACE LOW E OF EKN. FRONT WILL CLEAR THE MOUNTAINS BY 21Z. AS THE FRONT CROSSES...TEMPERATURE FALLS OF 7 TO 10 DEGREES CAN BE EXPECTED WITH GRADUALLY LOWERING TEMPS THEREAFTER THROUGH THE EVENING. LOW CIGS AND VSBY IN POST FRONTAL DZ CAN BE EXPECTED THRU THE REMAINDER OF THE AFTERNOON...ALONG WITH GUSTY NW WINDS. WILL WATCH -RA TO FILL BACK IN LATER THIS AFTERNOON AS THE UPPER LEVEL TROF CROSSES. AREA WILL BEGIN TO DRY OUT WITH PASSAGE OF THE UPPER LEVEL TROF...SAVE FOR SOME DZ HANGING ON ACROSS THE MOUNTAINS THIS EVENING. ELECTED TO KEEP POSSIBILITY OF IT ENDING AS A LITTLE FRZ DZ BUT NOT EXPECTING ANY IMPACTS. WHAT WILL NOT CLEAR OUT THIS EVENING IS THE LOW STRATUS. HOWEVER...DO EXPECT BASES TO LIFT A BIT TONIGHT. THINK SE OH WILL SCT OUT DURING THE PREDAWN. HOWEVER...DEVELOPING SUBSIDENCE INVERSION BENEATH THIS LINGERING MOISTURE WILL MAKE IT VERY DIFFICULT FOR STRATUS TO BREAK UP E OF THE OH RIVER OVERNIGHT. WITH WEAK CAA BENEATH THE INVERSION AND LOW LEVEL WINDS BECOMING MORE NE...FELT IT NECESSARY TO HOLD THE STRATUS IN ALONG THE CLIMATOLOGICAL FAVORED AREAS IN THIS SETUP....IE THE C LOWLANDS AND COAL FIELDS THRU THE MORNING HOURS. CLOUDS WILL GRADUALLY SCT OUT FROM NE TO SW...WITH AREAS ALONG AND S OF I64 CORRIDOR THE LAST TO LOSE THE STRATUS...POSSIBLY HOLDING ON UNTIL LATE AFTERNOON. FOR TEMPS...USED A BLEND OF LAMP AND HRRR FOR TEMPS TONIGHT. FOR SUNDAY...USED MET AS A BASE WHICH BETTER REFLECTED EXPECTED COOLER READINGS ALONG AND ESPECIALLY S OF I64 CORRIDOR DUE TO CLOUDS. FURTHER N...FELT LOCAL MOS WAS THE WAY TO GO WHERE READINGS SHOULD REACH INTO THE MID OR UPPER 40S. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... STILL A TOUGH CLOUD AND TEMPERATURE FORECAST FOR SUNDAY...WITH LOW LEVEL MOISTURE MOSTLY AOB 925 MB SUNDAY MORNING. WILL HOLD ONTO THOSE CLOUDS A BIT LONGER IN SOUTHERN COAL FIELDS OF WV. SURFACE HIGH PRESSURE QUICKLY PASSES OUR LONGITUDE SUNDAY AFTERNOON WITH LOW LEVEL FLOW VEERING TO EAST AND SOUTHEAST SUNDAY NIGHT. ANOTHER TOUGH TEMPERATURE FORECAST WITH 925 MB FLOW BLOWING AT 15 TO 25 KNOTS. SOME HIGH CLOUDS MAY ALSO BE AROUND SUNDAY NIGHT. WILL TRY TO DROP TEMPERATURES A BIT LOWER...BUT NOT AS LOW AS NAM AND GFS MOS GUIDANCE. THE SURFACE WAVE ALONG THE MID ATLANTIC COAST...TRYING TO GET ORGANIZED MONDAY INTO MONDAY NIGHT...MAY BRUSH OUR EASTERN MOUNTAIN COUNTIES WITH DEEPER MOISTURE...BUT CURRENTLY WILL ONLY HAVE CHANCE POPS THERE....BEFORE THAT DEEPER MOISTURE GETS SHUNTED EAST. THE EASTERN LOW LEVEL FLOW SHOULD KEEP THOSE UPSLOPE AREAS A BIT COOLER FOR MONDAY MAXIMUM TEMPERATURE. THE WESTERN THE DIGGING UPPER/MID LEVEL TROUGH FROM THE UPPER MIDWEST STARTS AFFECTING US TUESDAY WITH COLDER AIR BECOMING ESTABLISHED BY TUESDAY NIGHT. INCREASED POPS FOR SNOW SHOWERS...ESPECIALLY FOR TUESDAY NIGHT. OVERALL...NO MAJOR STORMS FORESEEN...BUT A COLDER PATTERN BY TUESDAY INTO WEDNESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MODELS INDICATE A HIGH PRESSURE MOVING OVER NEW ENGLAND...EXTENDING SOUTHWEST INTO WV SUNDAY NIGHT. ALTHOUGH A COLD AIR MASS WILL BE IN PLACE...THIS PATTERN WOULD BRING EAST TO SOUTHEAST FLOW...CAPABLE TO PRODUCE DOWNSLOPING WARMING ACROSS THE LOWLANDS SUNDAY NIGHT. INCREASED FEW DEGREES FROM HPC GUIDANCE ACCORDINGLY. FOR MONDAY...BUFKIT SOUNDINGS SHOW DRY AIR ALOFT WITH LIMITED MOISTURE IN THE VERY LOW LEVELS WHILE A H500 WEAK SHORTWAVE CROSSES THE AREA. KEPT LOW CHANCE POPS WITH THIS FEATURE...MORE ALONG THE GFS SOLUTION. THE ECMWF BRINGS STRONG COLD AIR ADVECTION FOR THE SAME TIME PERIOD WITH SUCH A WEAK WAVE. BELIEVE ECMWF IS OVERDOING CAA SO PREFERRED THE GFS. BY MONDAY NIGHT FLOW IN THE LOW LEVELS TURN NORTHWEST WITH SOME CAA FROM BOTH MODELS. FIGURE A GOOD SET UP FOR UPSLOPE PCPN. THE GFS BRINGS THE 0C LEVEL AROUND THE NORTHEAST MOUNTAINS WHILE IN THE ECMWF...THE 0C LINE GOES WAY SOUTH OF THE AREA. WENT WITH A BLEND SOLUTION EXPECTING CHANCE POPS WITH FEW SNOW SHOWERS OR MIX PCPN OVER THE MOST FAVORABLE UPSLOPE AREAS...AND RAIN ELSEWHERE. PCPN IS EXPECTED TO TAMPER OFF ON TUESDAY KEEPING CHANCE POPS OVER THE EASTERN MOUNTAINS ESPECIALLY WITH THE UPSLOPE COMPONENT AND DRY WEATHER SPREADING FROM SOUTHEAST OH...EAST. DRY WEATHER EXPECTED THROUGH THE REST OF THE PERIOD AS A HIGH PRESSURE BUILDS IN. WENT CLOSE TO HPC TEMPERATURES THROUGH THE PERIOD. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SURFACE FRONT WAS E OF CRW/CKB AS OF 18Z. EXPECT IT TO CROSS KEKN AND KBKW BY 20Z. CIGS AND VSBY WILL LOWER INTO IFR OR WORSE FOR A TIME IN POST FRONTAL DZ ACROSS MUCH OF THE AREA. WINDS WILL ALSO GUST IN THE 15 TO 20 KT RANGE...A BIT HIGHER WITH ACTUAL FROPA. ANOTHER ROUND OF SHRA POSSIBLE LATER THIS AFTERNOON AND INTO THE EARLY EVENING HRS WITH THE PASSAGE OF THE UPPER LEVEL TROF. ALLOWED TO VSBY TO IMPROVE INTO MVFR AND EVENTUAL VFR OVERNIGHT AS DRIER AIR ADVECTS IN NEAR THE SURFACE. ALSO ALLOWED CIGS TO LIFT A BIT INTO MVFR...FOLLOWING PASSAGE OF THE UPPER TROF. STILL HAVE CIGS BELOW 2 GRAND MARK THOUGH. THE LOW STRATUS SHOULD SCT OUT ACROSS SE OH OVERNIGHT...BUT WILL HANG TOUGH E OF THE OH RIVER TO AFFECT THE TAF SITES. THE LOW LEVEL FLOW WILL BECOME MORE NE OVERNIGHT WITH SOME GUSTS CONTINUING. THIS COMBINED WITH DEVELOPING SUBSIDENCE INVERSION WILL KEEP THE LOW STRATUS IN PLACE FIRST HALF OF SUNDAY...WITH KCRW AND KHTS PERHAPS NOT SCT OUT UNTIL AFTER END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR CONDITIONS MAY VARY. TIMING ERADICATION OF LOW STRATUS MAY VARY...POSSIBLY OCCURRING MUCH SOONER THAN CURRENTLY FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M M H H H H H H H H H H BKW CONSISTENCY H H H H H M M L L L L H EKN CONSISTENCY H H H L L L L L L L L L PKB CONSISTENCY H M H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SUNDAY... IFR POSSIBLE IN RAIN/SNOW MONDAY NIGHT INTO TUESDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...RPY/30/26 NEAR TERM...30 SHORT TERM...KTB LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
304 PM CST SAT DEC 6 2014 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 301 PM CST SAT DEC 6 2014 COMPLEX FORECAST OVER THE NEXT DAY AS AN UPPER WAVE MOVES ACROSS THE AREA...ACCOMPANIED BY A LOW PRESSURE MOVING ACROSS THE CANADIAN BORDER DRAGGING A COLD FRONT THROUGH THE REGION. AS OF THIS AFTERNOON...LOW STRATUS HAS ERODED AND PUSHED OFF TO THE SOUTH OF THE CWA. HOWEVER AS LOW LEVEL WINDS TURN MORE SOUTHEASTERLY AND SOUTHERLY AHEAD OF THE APPROACHING FRONT...EXPECT THIS STRATUS TO BEGIN STREAMING BACK INTO THE REGION. THE RAP SEEMS TO HAVE THE BEST HANDLE ON THIS...AND THINK THIS LOW STRATUS SHOULD APPROACH SIOUX CITY AROUND MIDNIGHT...PUSHING NORTH INTO THE EARLY MORNING HOURS...LIKELY MAKING IT EVERYWHERE ALONG AND EAST OF THE JAMES RIVER. NEXT QUESTION IS FOG POTENTIAL. ONE THING GOING AGAINST WIDESPREAD DENSE FOG IS THE STRONG SOUTHERLY BREEZE...WHICH WILL LIKELY BE AVERAGING 15 TO 25 MPH...GUSTING 25 TO 35 MPH. PROBABLY EVEN A BIT HIGHER ALONG THE BUFFALO RIDGE. HOWEVER MOISTURE IS SHALLOW AND NEAR THE GROUND...SO STRATUS COULD COME IN LOW ENOUGH TO RESULT IN DENSE FOG EVEN GIVEN THE WIND...WHICH THE RAP SUGGESTS. GIVEN THE UNCERTAINTY WILL JUST INCLUDE PATCHY FOG IN THE GRIDS FOR NOW...AND THE EVENING AND OVERNIGHT SHIFT WILL HAVE TO MONITOR TRENDS AND ADJUST AS NEEDED. THE NEXT QUESTION IS PRECIPITATION POTENTIAL. TWO ASPECTS TO THIS...DRIZZLE WITH THE LOW LEVEL MOISTURE...AND RAIN WITH THE UPPER LEVEL FEATURE AND FRONTOGENESIS. WITH REGARDS TO THE DRIZZLE POTENTIAL...MOISTURE IS ORIGINALLY PRETTY SHALLOW WHICH WOULD SEEM TO MAKE DRIZZLE UNLIKELY. BY LATER TONIGHT INTO TOMORROW MORNING MOISTURE DEPTH BEGINS TO INCREASE...AS DOES LIFT IN THE MOISTURE LAYER. THIS WOULD SEEM TO SUGGEST AN INCREASE IN THE DRIZZLE POTENTIAL BY MID MORNING EAST OF THE JAMES RIVER. THE PASSAGE OF THE FRONT WILL EVENTUALLY END THAT THREAT FROM WEST TO EAST THROUGH THE AFTERNOON. THE UPPER LEVEL WAVE AND MID LEVEL FRONTOGENESIS WILL TRY TO PRODUCE SOME LIGHT PRECIPITATION AS WELL FROM EARLY SUNDAY INTO THE AFTERNOON. QUITE A BIT OF MID LEVEL DRY AIR FOR THIS PRECIPITATION TO OVERCOME THOUGH...AND MOST MODELS ARE TRENDING DRIER. SO DID CUT BACK QPF...WITH BEST CHANCE OF MEASURABLE PRECIPITATION ALONG AND EAST OF INTERSTATE 29...WITH CHANCES INCREASING AS YOU GO EAST. LAST QUESTION IS PRECIPITATION TYPE. WITH QUITE A STRONG WARM NOSE ALOFT...THINK ANYTHING WILL EITHER BE LIGHT RAIN OR FREEZING RAIN. COULD SEE A BIT OF SLEET MIXED IN...BUT NOT EXPECTING IT TO BE A PREDOMINANT TYPE. THUS PTYPE WILL PROBABLY COME DOWN TO SURFACE TEMPERATURES. USED A BLEND OF RAW GUIDANCE...WEIGHTED TOWARDS THE GEM...ECMWF AND WRF ARW FOR HOURLY TEMPERATURES TONIGHT INTO TOMORROW. THIS WARMS SIOUX CITY ABOVE FREEZING BY 14Z...SIOUX FALLS BY 16Z AND THE REMAINDER OF THE CWA BY 18Z. THUS I DO THINK A PERIOD OF FREEZING DRIZZLE OR LIGHT FREEZING RAIN IS POSSIBLE. ALTHOUGH BY THE TIME THE DRIZZLE INCREASES...WE COULD VERY WELL BE ABOVE FREEZING...LIMITING THE FREEZING POTENTIAL. THE BEST CHANCE OF A LIGHT COATING OF ICE SEEMS TO BE EAST OF INTERSTATE 29 WHERE COLD AIR HOLDS ON A BIT LONGER. GIVEN THE UNCERTAINTY WILL HOLD OFF ON ANY ADVISORY. BUT THOSE WITH MORNING TRAVEL PLANS SHOULD KEEP ALERT OF THE FORECAST...AS EVEN JUST A LIGHT COATING OF ICE CAN CAUSE IMPACTS. EVENING AND OVERNIGHT SHIFT WILL HAVE TO MONITOR TRENDS...AND ISSUE ANY ADVISORY IF CONFIDENCE IN MORE WIDESPREAD FREEZING DRIZZLE OR LIGHT FREEZING RAIN INCREASES. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 301 PM CST SAT DEC 6 2014 THE MAIN FOCUS IN THE MEDIUM AND EXTENDED FOCUSES ON TEMPERATURES. WHILE MAJORITY OF PRECIPITATION WILL TAKE PLACE DURING THE DAY ON SUNDAY...WILL HAVE TO WATCH FOR LOW STRATUS ROTATING BACK INTO THE AREA BEHIND DEPARTING UPPER TROUGH SUNDAY NIGHT. SOUNDINGS SUGGEST A VERY LIGHT PRECIPITATION POTENTIAL...IN THE FORM OF FLURRIES/SPRINKLES/DRIZZLE. COLDER AIR WILL NOT QUITE MAKE IT SOUTHWARD ON MONDAY...BUT THE WESTERLY WIND AND LINGERING WARM AIR ALOFT WILL STILL ALLOW FOR ABOVE NORMAL TEMPERATURES. A MORE DIRECT COOLDOWN WILL ARRIVE ON TUESDAY AS SURFACE HIGH PRESSURE MOVES OVERHEAD. THE MISSOURI RIVER VALLEY MAY STILL REACH THE MID 30S...BUT AREAS FURTHER NORTHEAST COULD STRUGGLE TO CLIMB ABOVE FREEZING. LOW LVL WARM ADVECTION BEGINS LATE TUESDAY AS MID-LVL HEIGHTS RISE OVER THE CENTRAL CONUS. GFS/ECMWF CONSISTENT NOW IN BRINGING A WEAK SHORTWAVE THROUGH THE AREA TUESDAY NIGHT AND WEDNESDAY...BUT LITTLE IMPACT IS ANTICIPATED OTHER THAN CLOUD COVER. THEN BEGINS A STRETCH OF ABOVE NORMAL TEMPERATURES...SOME THAT COULD RIVAL SOME OF OUR WARMER TEMPERATURES RECORDED IN DECEMBER. MODELS STILL DIFFERING TO SOME DEGREE ON MOISTURE RETURN AND IMPACT ON STRATUS ACROSS THE REGION. ALOFT...TEMPERATURES ARE SURELY IMPRESSIVE WITH 925MB TEMPERATURES BY SATURDAY APPROACHING +10C...AND 850MB TEMPERATURES AROUND +15C...SOME OF THE WARMEST READINGS RECORDED VIA SOUNDINGS IN DECEMBER AT ABERDEEN. MODEL PREFERENCE CONTINUES TO FALL WITH THE ECMWF...WHICH DOES SHOW STRATUS ADVECTING INTO THE AREA BY THURSDAY...BUT IS NOT NEARLY AS AGGRESSIVE AS THE TYPICALLY OVERSATURATED GFS AND SUGGESTED A SLIGHTLY MORE VEERED LOW LVL FLOW. THAT SAID...FOR TEMPERATURES WED- SAT UTILIZED A BLEND OF WPC AND ECMWF...WHICH FALL ON THE WARMEST SIDE OF GUIDANCE AND STILL MAY NOT BE WARM ENOUGH FOR SATURDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1132 AM CST SAT DEC 6 2014 COMPLEX FORECAST OVER THE NEXT 24 HOURS. STRATUS NEAR KSUX CONTINUES TO DISSIPATE AND MOVE OFF TO THE SOUTHWEST...AND EXPECT THEM TO BE VFR BY 19 OR 20Z. HOWEVER...AS THE SOUTHERLY LOW LEVEL JET INCREASES TONIGHT...EXPECT THIS STRATUS TO RETURN TO THE AREA. TIMED THIS USING A MODEL CONSENSUS...WEIGHTED TOWARDS THE RAP WHICH CURRENTLY HAS THE BEST HANDLE OF THINGS. UNCERTAINTY ON HOW LOW THE CIGS GET...SO KEPT IFR FOR NOW...BUT WOULD NOT BE SURPRISED TO SEE AREAS OF LIFR. ALSO THE SOUTHERLY BREEZE MAY KEEP DENSE FOG FROM FORMING...ALTHOUGH STRATUS MAY COME IN LOW ENOUGH THAT WE DO INDEED GET DENSE FOG. SO IN SUMMARY...CONFIDENCE ON AT LEAST MVFR TO IFR CIGS IS HIGH TONIGHT INTO TOMORROW MORNING...CONFIDENCE ON TIMING IS MODERATE...WITH LOW CONFIDENCE ON EXACT CIG HEIGHT AND VISIBILITY. OTHER CONCERN IS DRIZZLE OR FREEZING FRIZZLE. THIS IS CERTAINLY A POSSIBILITY WITH THE STRATUS...ALTHOUGH WOULD LIKE TO SEE A DEEPER LAYER OF SATURATION. THUS CONFIDENCE REMAINS LOW ON THIS AND WILL KEEP OUT OF THE TAFS FOR NOW. ALSO MAY SEE A PERIOD OF LIGHT RAIN OR FREEZING RAIN AS THE FRONT AND WAVE PASS ACROSS TOMORROW MORNING. BUT BEST CHANCE OF THIS IS EAST OF INTERSTATE 29...SO WILL KEEP THE TAFS DRY. BUT WITH THE LIGHT FREEZING RAIN OR DRIZZLE POTENTIAL...WILL NEED TO MONITOR TRENDS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...DUX AVIATION...CHENARD