Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/26/13


AREA FORECAST DISCUSSION
NWS TUCSON AZ
925 PM MST SAT NOV 23 2013 .SYNOPSIS...LOW PRESSURE OVER SOUTHEASTERN CALIFORNIA AND SOUTHWEST ARIZONA THIS EVENING WILL MOVE NORTHEAST ACROSS ARIZONA TONIGHT INTO SUNDAY. THIS SYSTEM WILL CONTINUE TO BRING PERIODS OF VALLEY RAIN AND MOUNTAIN SNOW THROUGH TONIGHT. RAIN AND MOUNTAIN SNOW WILL DECREASE FROM WEST TO EAST SUNDAY FOLLOWED BY A FEW LINGERING SNOW SHOWERS ACROSS THE WHITE MOUNTAINS MONDAY. DRY CONDITIONS WILL THEN PREVAIL MONDAY NIGHT THROUGH FRIDAY. A GRADUAL WARMING TREND EXPECTED DURING THE UPCOMING WEEK. && .DISCUSSION...WATER VAPOR IMAGERY SHOWS THE UPPER LOW SPINNING ACROSS EXTREME SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA. RADAR MOSAIC SHOWS ISOLATED SHOWERS OCCURRING OVER MAINLY CENTRAL AND EASTERN PORTIONS OF THE FORECAST AREA AT THIS TIME. HRRR MODEL SHOWS GENERALLY ISOLATED TO LOW END SCATTERED ACTIVITY...BUT REDEVELOPMENT OCCURS AFTER MIDNIGHT OVER THE EASTERN ZONES THROUGH THE EARLY MORNING HOURS. THAT SAID...THE WINTER STORM WARNING AND ADVISORIES FOR THE REMAINDER OF THE NIGHT AND INTO EARLY SUNDAY CONTINUE TO LOOK GOOD. DAY SHIFT MAY BE ABLE TO CANCEL THESE PRODUCTS EARLIER IF THE SHOWERS EXIT AS EARLY AS THE HRRR IS INDICATING. LOW TEMPERATURES EXPECTED TO DROP INTO THE MID 30S TO MID 40S ACROSS SOME OF THE CENTRAL DESERTS AND EASTERN VALLEYS. WITH CURRENT DEWPOINT READINGS IN THE MID 30S TO MID 40S WE COULD SEE SOME FOG... ESPECIALLY FOR AREAS EAST OF TUCSON TOWARD VAIL AND THEN TO THE SOUTH TOWARD SONOITA...SIMILAR TO WHAT OCCURRED YESTERDAY EVENING AT ABOUT THIS TIME. THIS IS AN AREA THAT RECEIVED SIGNIFICANT RAINS IN THE PAST COUPLE OF DAYS...AND WITH COOLER AIR ADVECTING IN FROM THE EAST SOME FOG MAY DEVELOP ONCE AGAIN. WILL ADD A MENTION OF PATCHY FOG IN THE FORECAST FOR THE REMAINDER OF TONIGHT. AS OF 04Z (9 PM MST)...TEMPERATURES RANGED FROM THE LOWER 40S TO THE MID 50S AND THESE READINGS ARE MOSTLY ON TRACK WITH EXPECTED OVERNIGHT LOW TEMPERATURES...SO NO CHANGES ARE PLANNED...BUT WILL CONTINUE TO MONITOR. DETAILS REGARDING THE FORECAST BEYOND TONIGHT ARE BELOW IN THE PREVIOUS DISCUSSION SECTION. && .AVIATION...EAST OF KTUS-KOLS LINE...WIDESPREAD RAIN AND HIGHER ELEVATION SNOW WILL SHIFT EAST ACROSS SE AZ THROUGH TONIGHT INTO SUNDAY MORNING WITH WIDESPREAD MVFR CIGS/VSBYS/MT OBSCURATIONS AND OCCASIONAL IFR CIGS/VSBYS FORECAST. WEST OF KTUS-KOLS...A FEW RAIN AND HIGH ELEVATION SNOW SHOWERS WILL LINGER THROUGH TONIGHT. IFR VSBYS IN FOG AND MT OBSCURATIONS PSBL WEST OF THIS LINE OVERNIGHT. SURFACE WINDS WILL GENERALLY BE ELY/SELY 8-15 KTS WITH GUSTS TO 20 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...LOW PRESSURE WILL MOVE NORTHEAST ACROSS AZ THE REMAINDER OF THE WEEKEND. OVER SE AZ...RAIN AND MOUNTAIN SNOW WILL SHIFT EAST TONIGHT AND END SUNDAY NIGHT IN THE WHITE MOUNTAINS. DRY CONDITIONS WILL PREVAIL DURING THE COMING WORK WEEK WITH COOLER THAN AVERAGE TEMPERATURES RETURNING TO NEAR NORMAL BY THANKSGIVING. WINDS ARE NOT EXPECTED TO BE OVERLY STRONG THROUGH THE PERIOD ALTHOUGH EASTERLY WINDS COULD GET GUSTY TUESDAY NIGHT INTO EARLY WEDNESDAY THROUGH MOUNTAIN GAPS AND PASSES. && .CLIMATE...TODAYS RAINFALL AT THE TUCSON INTERNATIONAL AIRPORT AS OF 2 PM STOOD AT 1.22" WHICH BRINGS THE 3 DAY STORM TOTAL TO 2.11". THE 2.11" RANKS AS THE 3RD WETTEST NOVEMBER THREE DAY RAIN EVENT IN TUCSON. THE TOP TWO ARE 2.83" IN 1895 AND 2.39" IN 1900. THE MONTH TOTAL OF 2.23" RANKS AS THE 7TH WETTEST NOVEMBER ON RECORD. TODAYS TOTAL OF 1.22" RANKS AS THE 8TH WETTEST NOVEMBER DAY ON RECORD. && .PREVIOUS DISCUSSION...AS THE LOW MOVES THROUGH THE STATE ON SUNDAY...IT WILL SLOWLY FILL BUT STILL PLENTY OF MOISTURE AROUND ALONG WITH COLD POOL ALOFT TO KEEP SCATTERED SHOWERS IN THE FORECAST. SYSTEM EAST OF THE AREA ON MONDAY WITH MUCH COLDER OVERNIGHT LOWS TUESDAY INTO WEDNESDAY. ADDING FROST TO THE FORECAST FOR PORTIONS OF THE EASTERN ZONES. WARMING TREND STARTING MONDAY AND CONTINUING INTO TURKEY DAY WHERE HIGHS WILL BE AT OR SLIGHTLY ABOVE NORMAL. MODELS HINTING AS ANOTHER PACIFIC STORM HEADED FOR THE DESERT SW NEXT SUNDAY WHICH IS JUST OUTSIDE OF OUR 7 DAY FORECAST. SOMETHING TO WATCH THOUGH. && .TWC WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 11 AM MST SUNDAY FOR AZZ510-511. WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR AZZ512-514. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
242 PM MST SUN NOV 24 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 ...SNOW WINDING DOWN ON MONDAY... UPPER LOW IS NOW NOW MOVING EASTWARD ALONG THE CO NM BORDER. COLDER CLOUD TOPS HAVE SHIFTED TO THE NE PORTION OF CO...WHERE SEVERAL BANDS OF SNOW ARE ROTATING NORTHWESTWARD ALONG THE NRN I-25 CORRIDOR. THE LOW HAS DEFINITELY TAKEN A MORE NRN TRACK AS THE NAM AND ESPECIALLY THE ECMWF HAD FORECAST IT TO DO. HOWEVER...NOT A LOT OF MOISTURE LEFT WITH THE SYSTEM...AND ACCUMS TONIGHT INTO MON MORNING PROBABLY WILL NOT BE ALL THAT IMPRESSIVE. MAIN FOCUS FOR HEAVIER ACCUMS WILL BE DUE TO N-NE WINDS INCREASING TONIGHT AS THE LOW CONTINUES TO MOVE AWAY. LATEST RUC SHOWING H7 WINDS INCREASING TO 30-40 KTS AFTER ABOUT 04Z TONIGHT. THIS WILL LEAD TO SOME DECENT OROGRAPHIC ACCUMS OVER THE HIGHER ELEVATIONS OF THE ERN MT RANGES OVERNIGHT...AND FAVORED SPOTS LIKE CUCHARA COULD SEE SOME RESPECTABLE SNOWFALL. LATEST HI RES MODELS REALLY SHOWING THIS POTENTIAL OVER THE WETS AND NRN SANGRES...SO WILL ADD THE WETS TO THE CURRENT SUITE OF ADVISORIES WE HAVE OUT THROUGH 12Z MONDAY. ELSEWHERE...BEST BET OF SNOW OVER THE PLAINS WILL BE ALONG AND WEST OF I-25...AND ESPECIALLY SOUTH OF HIGHWAY 50. COULD SEE SOME LIGHT ACCUMS OVER THE HIGHER TRRN BUT NOT EXPECTING ANYTHING SIGNIFICANT. INHERITED LOW POPS FOR THE PLAINS STILL LOOK ON TARGET SO HAVE NOT MADE ANY EXTENSIVE CHANGES THERE. SHOULD SEE SNOW TAPER OFF FROM N TO S ESPECIALLY AFTER MID-MORNING ON MONDAY. JUST A FEW LINGERING SHOWERS OVER THE SRN MTS AND FAR SERN PLAINS BY MON AFTERNOON. BREEZY CONDITIONS WILL PERSIST IN THE WAKE OF THE LOW...ESPECIALLY OVER BACA COUNTY WHICH COULD SEE SOME GUSTS IN THE 30-40 KT RANGE FOR THE LATE MORNING TO EARLY AFTERNOON PERIOD. TEMPS ALOFT WILL ACTUALLY BE FALLING SIGNIFICANTLY THROUGH MONDAY MORNING...DOWN TO AROUND MINUS 7 OR 8 C AT H7...BUT WITH GOOD MIXING IN THE LOW TO MID LEVELS...SHOULD SEE TEMPS TOP OUT HIGHER THAN THE TEMPS THIS AFTERNOON. HAVE CUT BACK TEMPS A BIT BELOW GUIDANCE HOWEVER...SINCE EVEN WITH GOOD ADIABATIC MIXING THE TEMPS ALOFT WILL PROBABLY ONLY SUPPORT 40 DEGREES OR SO AT BEST BY THE AFTERNOON. SO...IT WILL BE A RAW DAY DESPITE THE LOWERED POPS. ROSE .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 241 PM MST SUN NOV 24 2013 MONDAY NIGHT...UPPER LOW OVER WEST TEXAS FORECAST BY MODELS TO SLIDE SOUTHEAST...BUT SOME MOISTURE IN NORTHERLY FLOW ALOFT WILL PERSIST THROUGH PART OF THE NIGHT. INHERITED ISOLATED POPS AT MOST OVER THE EASTERN MOUNTAINS THROUGH MIDNIGHT...AND THAT LOOKS GOOD. SNOW ACCUMULATIONS WILL BE WELL UNDER AN INCH. LOW TEMPERATURES WILL BE IN THE LOWER SINGLE DIGITS ACROSS THE SAN LUIS VALLEY...WITH SNOW COVER AND RADIATIONAL COOLING. ELSEWHERE...TEMPERATURES SHOULD DIP INTO THE TEENS ACROSS THE PLAINS AND OTHER HIGH VALLEYS...WITH SINGLE DIGITS ACROSS THE HIGHEST ELEVATIONS. FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND...THE WEATHER LOOKS TO BE FAIRLY TRANQUIL...AS AN UPPER LEVEL RIDGE GETS ESTABLISHED OVER THE GREAT BASIN AND ROCKIES. A WEAK FRONT MAY BRIEFLY AFFECT THE EASTERN PLAIN THANKSGIVING DAY...BUT WITH NO PRECIPITATION. A COUPLE MORE SHORTWAVES IN THE NORTHERN STREAM...WILL BRING SOME CLOUDS...WITH THE SECOND ONE...DURING THE WEEKEND...BRINGING A CHANCE FOR SOME HIGHER ELEVATION SNOW SHOWERS. -TLM- && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY AFTERNOON) ISSUED AT 241 PM MST SUN NOV 24 2013 SNOW SHOWERS LINGERING OVER NRN EL PASO COUNTY SHOULD CONTINUE TO MOVE OFF TO THE NW LATE THIS AFTERNOON. NO SIGNIFICANT ACCUMULATIONS ARE EXPECTED WITH THIS ACTIVITY. KCOS COULD SEE ANOTHER ROUND OF INTERMITTENT LIGHT SN LATER THIS EVE...BUT IT SHOULD NOT LAST LONG AND SHOULD NOT LINGER MUCH BEYOND 12Z MON. KPUB WILL SEE CHANCES OF SNOW LINGER A BIT LONGER INTO MON MORNING...BUT NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS THERE EITHER. IT CURRENTLY LOOKS LIKE MOST OF THE HEAVIER SNOWFALL OVERNIGHT WILL STAY SOUTH OF HIGHWAY 50. KALS WILL SEE A GOOD CHANCE OF LIGHT SNOW THROUGH THIS EVE AND OVERNIGHT...WITH LIGHT ACCUMS OF A COUPLE INCHES POSSIBLE BY EARLY MONDAY. SHOULD SEE CONDITIONS IMPROVE FROM NW TO SE THROUGH MONDAY...WITH JUST SOME LINGERING SHOWERS OVER THE HYR TRRN. MAIN STORY TOMORROW WILL BE THE INCREASED N-NE WINDS...WHICH WILL REMAIN GUSTY OVER THE PLAINS THROUGH THE EARLY AFTERNOON BEFORE QUIETING DOWN LATER IN THE DAY. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ060-066- 073>075-080. WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ068. && $$ SHORT TERM...ROSE LONG TERM...TM AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1030 PM MST SAT NOV 23 2013 .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) ISSUED AT 311 PM MST SAT NOV 23 2013 COMPLEX PATTERN TODAY AS COLDER AIR MOVED INTO SOUTHEAST UTAH... LOWERING THE SNOW LEVELS TO THE VALLEY FLOORS. BUT SOUTHWEST COLORADO HAS STAYED IN THE WARM SECTOR WITH THE SNOW LEVEL AROUND 8000 FEET. TELLURIDE AWOS OBSERVED LIGHT RAIN EARLIER TODAY. SOUTHWEST COLORADO HAS BEEN A CHALLENGE WITH RESPECT TO PRECIPITATION TYPE DURING THE PAST DAY OR TWO. CONFIDENCE IS INCREASING THAT SNOW LEVELS WILL LOWER TO THE VALLEY FLOORS (EXCEPT SOUTH OF CORTEZ) AS THE MOIST CONVEYOR BELT OVER ERN ARIZONA SHIFTS INTO NWRN NEW MEXICO AND EXTREME SWRN COLORADO. MID LEVEL TEMPS IN THE CONVEYOR BELT ARE COLDER AND DIABATIC COOLING PROCESSES WILL RESULT IN RAIN CHANGING OVER TO SNOW. WITH SOUTHEAST LOW LEVEL FLOW...THE RAP AND DOWNSCALED 5KM NAM SHOW THE QPF BULLSEYE ALONG THE MONTEZUMA/LA PLATA COUNTY LINE AND MONTICELLO UTAH WITH AREAS EXCEEDING 1 INCH OF PCPN DURING THE NEXT 12 HOURS. THIS EQUATES TO A SNOW ACCUMULATION OF 6-12 INCHES OF "SIERRA CEMENT" (HEAVY WET SNOW) FOR THE THIS AREA OVERNIGHT. FOR EAST CENTRAL UTAH AND THE UNCOMPAHGRE/GRAND VALLEY...SOUTHEAST FLOW WILL A WARMING EFFECT THAT ERODES THE COLDER SURFACE AIR. THIS ELIMINATES THE CHANCE OF A REPEAT PERFORMANCE OF HEAVY SNOW FROM CANYONLANDS NATIONAL PARK TO DEBEQUE CANYON. THE OVERRUNNING PATTERN WILL NO LONGER EXIST AND THE AREAL EXTENT OF PRECIPITATION WILL HAVE LESSENED. FARTHER NORTH...MOSTLY DRY ALTHOUGH SOME DISSIPATING BANDS OF LIGHT SNOW MAY GENERATE FLURRIES OVER NE UTAH/NW COLORADO. SUNDAY AND SUNDAY NIGHT...THE CLOSED UPPER LOW WILL BE WEAKENING AS IT MOVES INTO NWRN NEW MEXICO. ACTIVE WEATHER WILL STILL EXIST BENEATH THE UPPER LOW SO ACCUMULATING SNOW CONTINUES ACROSS SW COLORADO. THE MOISTURE FIELD OVER ERN UTAH AND NORTHWEST COLORADO WILL BE ERODING. AS THE LOW CONTINUES TO TRACK ACROSS NEW MEXICO...LOW LEVEL FLOW BECOMES NORTHWEST WHICH FAVORS THE NWRN SAN JUANS AND THE SRN UNCOMPAHGRE PLATEAU (DALLAS DIVIDE/RIDGWAY AND OURAY). HOWEVER...SNOW RATES WILL BE DIMINISHING AS THE UPPER LOW WILL BE MOVING DOWNSTREAM. BY THE TIME THE UPPER LOW DOES DEPART THE REGION LATE SUNDAY NIGHT...STORM TOTAL QPF AND SNOWFALL WILL BE QUITE IMPRESSIVE FOR THE SRN PORTION OF THE FORECAST AREA. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 311 PM MST SAT NOV 23 2013 THE UPPER LOW WILL HAVE TRANSLATED EAST OF THE ROCKIES TO NEAR THE TEXAS PANHANDLE BY SUNRISE ON MONDAY...THEN BE FORCED SOUTHWARD BY A STRONG DIP IN THE NORTHERN STREAM ACROSS THE UPPER MISSISSIPPI VALLEY. LINGERING WRAP AROUND MOISTURE WILL BE EXITING THE FAR SOUTHERN CWA BY LATE MORNING AS THE UPPER LOW BEGINS TO BE FORCED SOUTHWARD. THE RETREATING MOISTURE WILL BE REPLACED BY ANOTHER BATCH OF HIGH LEVEL MOISTURE BEING TRANSPORTED IN ON THE NORTHERLY STREAM. NAM/GFS DIFFERING A BIT WITH THE GFS SATURATING THE UPPER END OF THE DENDRITIC LAYER NEAR 500MB. THE NAM A BIT MORE AGGRESSIVE WITH SATURATION DOWN TO THE TOP OF THE NORTHERN DIVIDE MOUNTAINS THROUGH A LARGER PORTION OF THE DENDRITIC LAYER. ASCENT IS WEAK WITH OROGRAPHICS THE MAIN DRIVER IN THE NORTH FLOW SO WOULD EXPECT ANY ACCUMULATIONS TO BE ON THE LIGHT SIDE. FOR NOW WILL KEEP JUST SOME SMALL POPS IN PLACE THROUGH THE AFTERNOON UNTIL MODEL AGREEMENT ALIGNS BETTER. TEMPERATURES ARE SURE TO BE AFFECTED BY THE SNOW COVER ESPECIALLY OVER SOUTHEAST UTAH INTO SOUTHWEST COLORADO SO UNDERCUT GUIDANCE NUMBERS IN MANY AREAS. THERE SHOULD BE SLOW WARM-UP GOING INTO THE MID TO LATE WEEK PERIOD THOUGH THE STRONG NORTHERN STREAM FLOW JUST OFF TO OUR NORTHEAST WILL CONTINUE TO REINFORCE THE COLD AIR ALOFT. VALLEY INVERSIONS STRENGTHENED BY SNOW PACK WILL CONTINUE TO PUT A DAMPER ON WARMING SO AGAIN TEMPERATURES FROM BLENDED MODELS WERE LOWERED. A WEAK WAVE PASSAGE ON THURSDAY MAY BRING A BIT OF PASSING HIGH CLOUDINESS BUT IS NOT LIKELY TO ADD MUCH TO MIXING. OUT WEST...THE EASTERN PACIFIC TROF WILL BE SPLITTING WITH ONE BATCH CATCHING THE WESTERLIES ACROSS THE NORTHERN CONUS BORDER. THE OTHER MAIN BATCH WILL CLOSE OFF ANOTHER LOW ALONG THE CALIFORNIA COASTLINE. SOME OF THIS SOUTHERN ENERGY SHEARS OUT OF THE LOW AND PROGRESSES ACROSS THE CENTRAL ROCKIES PULLING MOISTURE WITH IT. FOR NOW IT SEEMS THIS WILL BE MAINLY IN THE FORM OF HIGH CLOUDINESS THROUGH THE LATE WEEK PERIOD. SO FOR NOW A MAINLY DRY FORECAST LOOKS ON TRACK FOR HOLIDAY TRAVEL WITH TEMPERATURES GRADUALLY WARMING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1022 PM MST SAT NOV 23 2013 VERY SIMILAR SCENARIO TO LAST NIGHT...AN AREA OF ENERGY AND MOISTURE LIFTING ACROSS WESTERN COLORADO AND EASTERN UTAH TONIGHT WITH A SOUTHERN EDGE OF MODERATE RAIN CURRENTLY NEAR KAIB. ANOTHER BATCH OF PRECIP IS BEING PUSHED UP AGAINST THE SAN JUANS IN THE FORM OF SNOW. EXPECT DETERIORATING FLIGHT CONDITIONS OVER MANY OF THE TAF SITES OVERNIGHT WITH THE BIGGEST IMPACTS OVER KDRO AND KTEX. RAIN SHOULD CHANGE OVER TO SNOW BY MORNING AT ALL SITES. MOUNTAIN OBSCURATION WILL BE PROMINENT OVER MANY AREAS THROUGH SUNDAY NIGHT BEFORE SOME DRYING BEGINS TO PUSH IN FROM THE NORTH. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER STORM WARNING UNTIL 3 AM MST MONDAY FOR COZ018-019. WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR COZ021. WINTER STORM WARNING UNTIL NOON MST SUNDAY FOR COZ022-023. UT...WINTER STORM WARNING UNTIL 3 AM MST MONDAY FOR UTZ028. WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR UTZ029. && $$ SHORT TERM...PF LONG TERM...15 AVIATION...JAM
AREA FORECAST DISCUSSION
NWS ALBANY NY
345 PM EST SUN NOV 24 2013 .SYNOPSIS... THE CENTER OF THIS ARCTIC AIRMASS WILL MOVE ACROSS THE REGION TONIGHT. WHILE SOME LAKE EFFECT CLOUDS AND SNOW SHOWERS ARE POSSIBLE...THE SURFACE HIGH WILL BUILD INTO THE REGION FOR SKIES TO BECOME MAINLY CLEAR OVERNIGHT. WINDS WILL SUBSIDE AND TEMPERATURES WILL FALL TO THE LOWEST LEVELS THIS SEASON THUS FAR. AS THIS HIGH MOVES OFFSHORE...WE TURN OUR ATTENTION TO A DEVELOPING COASTAL STORM THAT WILL IMPACT THE REGION HEADING INTO THE THANKSGIVING HOLIDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE CENTER OF THIS ARCTIC AIRMASS WILL SETTLE ACROSS THE REGION TONIGHT. THOSE H850 TEMPS PER THE RUC13 BOTTOM OUT NEAR -20C THIS EVENING. THIS WILL KEEP LAKE EFFECT ACTIVITY GOING FOR MOST OF THE NIGHT...HOWEVER...INVERSION LEVELS WILL DROP AS THAT SURFACE AND LOW LEVEL RIDGE AXIS CREST OVER THE REGION. LOW LEVEL WINDS CURRENTLY AROUND 330-350 DEGREES ARE EXPECTED TO BACK TOWARD 310-330 DURING TONIGHT THEN GRADUALLY TOWARD 270 DEGREES TOWARD SUNRISE. WE WILL RETAIN SLIGHT CHANCE TO CHANCE POPS FOR SNOW SHOWERS FOR PORTIONS OF THE CATSKILLS...SCHOHARIE VALLEY AND EVENTUALLY INTO THE MOHAWK VALLEY AND ADIRONDACKS THROUGH THE OVERNIGHT. CLOUDS TOO WILL BE PROBLEMATIC AND MOST OF THE REGION SHOULD BECOME MOSTLY CLEAR OVERNIGHT. LAKE CLOUDS WILL HANG ON CLOSER TO THE LAKES WHERE THE AFOREMENTIONED AREAS WHERE LAKE EFFECT SNOW SHOWERS ARE EXPECTED. TEMPERATURES WILL DROP BACK AT OR BELOW ZERO FOR THE ADIRONDACKS TO SINGLE DIGITS AND AROUND 10 DEGREES ELSEWHERE. AS FOR THE WINDS...WE WILL RETAIN THE ADVISORY THROUGH THE EVENING HOURS BUT EXPECTATIONS ARE FOR THE BOUNDARY LAYER TO DECOUPLE AND/OR FOR THE RIDGE TO BUILD IN TO ALLOW THE WIND GUSTS TO SUBSIDE BELOW ADVISORY LEVEL. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... ...POTENT COASTAL STORM IS EXPECTED TO IMPACT THE REGION TUESDAY INTO THURSDAY... MOST OF THE ATTENTION ON THIS FORECAST HAS BEEN ON THE DEVELOPING COASTAL STORM SET TO IMPACT HOLIDAY TRAVEL LEADING INTO THANKSGIVING. LATEST TRENDS IN THE NCEP MODEL SUITE ALONG WITH INTERNATIONAL GLOBAL MODELS ARE TRENDING A LITTLE FURTHER WEST /THE GFS IS QUICKLY TRENDING IN THIS DIRECTION ALONG WITH THE MOST OF THE ENSEMBLE MEMBERS/. THIS WOULD SUGGEST THAT THE BULK OF THE PRECIPITATION WILL FALL IN THE FORM OF RAIN FROM THE HUDSON RIVER VALLEY AND POINTS SOUTH AND EAST THROUGH THE HEART OF THE EVENT. HOWEVER...WITH A FAIRLY TIGHT BAROCLINIC ZONE AND ANY SLIGHT DEVIATION TO THIS TRACK WILL HAVE SIGNIFICANT IMPACTS TO PRECIP TYPE ACROSS THE REGION. PER THE LOW LEVEL U/V COMPONENT FROM THE GEFS...AT THIS TIME THE WARM AIR SHOULD ERODE THE COLDER AIR FOR THE EASTERN 2/3RD OF THE CWFA AS WE WILL TREND IN THIS DIRECTION FOR THE FORECAST. MONDAY... SURFACE HIGH CRESTS OVER THE REGION WITH LAKE EFFECT ACTIVITY IMPACTING PORTIONS OF THE DACKS IN THE MORNING AS THE LOW LEVEL FLOW CONTINUES TO BACK THROUGH THE DAY. OTHERWISE...MOST OF THE DAY SHOULD REMAIN DRY AS TEMPERATURES REBOUND INTO THE 20S AND SOME LOWER 30S AS THE H850 TEMPS "WARM" INTO THE NEGATIVE SINGLE DIGITS TO AROUND -10C DURING THE AFTERNOON. WITHIN THIS WARM ADVECTION...SOME INCREASE IN HIGH AND MID LEVEL CLOUD COVER IS ANTICIPATED. MONDAY NIGHT... A RATHER FAST MOVING CLIPPER TYPE SYSTEM TRACKING IN-BETWEEN THE GREAT LAKES REGION AND JAMES BAY WILL BRING A COLD FRONT ACROSS THE REGION. THIS MAY TOUCH OFF SOME SNOW SHOWERS...ESPECIALLY DOWNWIND OF LAKE ONTARIO...WITH ACCUMULATIONS 1-2 INCHES IN PERSISTENT SNOW SHOWERS WILL GENERALLY ONE INCH OR LESS FOR THE CWFA. TUESDAY INTO WEDNESDAY... AS SEEN IN THE H2O VAPOR LOOP...CUT OFF UPPER LOW OVER THE FOUR CORNERS REGION AND A COUPLE OF STRONG PV IMPULSES APPROACHING LAKE WINNIPEG ARE EXPECTED TO CARVE OUT A RATHER SIGNIFICANT TROUGH OVER THE EASTERN THIRD OF THE CONUS DURING THIS TIME STEP OF THE FORECAST. THESE WAVES ARE EXPECTED TO PHASE WITH CYCLOGENESIS EVOLVING OVER THE SOUTHEAST-MID ATLANTIC REGION DURING WEDNESDAY. A PRONOUNCED AGEOSTROPHIC RESPONSE WILL DEVELOP AS THE LOW LEVEL WARM ADVECTION RAPIDLY INCREASES UP THE EASTERN SEABOARD. PWAT ANOMALIES OF 1-3 STANDARD DEVIATIONS ABOVE NORMAL ARE EXPECTED FOR MOST OF THE REGION WITH THE LOW LEVEL JET APPROACHING 4 STANDARD DEVIATIONS ABOVE NORMAL. THE NAM IS THE OUTLIER WITH ITS EXCEPTIONALLY HIGH QPF WITH THE GLOBAL MODELS MUCH MORE TAME AND IN CLOSE AGREEMENT WITH 1-2 INCHES OF RAIN/WATER-EQUIVALENT FOR THE EVENT. PRECIPITATION FROM THIS EVOLVING SYSTEM IS EXPECTED TO DEVELOP SOUTH TO NORTH DURING TUESDAY AND OVERSPREAD THE REGION TUESDAY NIGHT. AT THIS TIME...WITH A SLIGHTLY FURTHER WEST SOLUTION...WE UTILIZED A BLENDED PARTIAL THICKNESS SCHEME FROM THE GLOBAL MODELS WHICH SUGGESTS A LITTLE LIGHT SNOW INITIALLY THEN QUICKLY CHANGING OVER TO A MIX LATE TUESDAY THEN CONTINUING TO WARM TUESDAY NIGHT FROM AT LEAST THE HUDSON RIVER VALLEY AND POINTS SOUTH AND EAST. TO THE WEST OF THIS LINE...A POTENTIALLY PROLONGED PERIOD OF WINTRY MIX IS EXPECTED AS THIS MAY PROVE TO TO BE VERY CHALLENGING ASPECT TO THIS FORECAST. IN COLLABORATION WITH WPC-WWD...A SIGNIFICANT AMOUNT OF SNOW/SLEET/FREEZING RAIN IS POSSIBLE FOR PORTIONS OF THE DACKS...WESTERN MOHAWK VALLEY AND PERHAPS INTO THE SCHOHARIE VALLEY. WE WILL CONTINUE TO HIGHLIGHT IN THE HWO. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WEDNESDAY NIGHT THROUGH THURSDAY...THE 12Z MODELS AND GUIDANCE CONTINUE TO SHOW A COASTAL STORM MOVE UP THE ATLANTIC COASTLINE. THERE IS STILL A LARGE DISAGREEMENT IN TERMS WHAT THE PRECIPITATION TYPE AND THE AMOUNT OF QPF THAT WILL ACCUMULATE BETWEEN THE FORECAST MODELS. AS WE GO INTO LATE WEDNESDAY NIGHT...SOME NEW 12Z MODEL DATA SHOWS A SECONDARY SURFACE LOW PRESSURE SYSTEM DEVELOPING ACROSS CENTRAL NEW ENGLAND WITHIN A FAVORABLE SYNOPTIC UPPER LEVEL DIVERGENCE REGION EMBEDDED IN A STRONG VERTICALLY ORIENTED UPPER LEVEL JET...ACCOMPANIED BY A DEVELOPING NEGATIVE TILTED UPPER LEVEL TROUGH MOVING EAST FROM LAKE ERIE OVER CENTRAL PENNSYLVANIA. IF THIS MODEL RUN WERE TO VERIFY...COLD NORTH TO NORTHWESTERLY FLOW ON THE BACKSIDE OF THE DEPARTING LOW PRESSURE SYSTEM WILL ANCHOR IN ENOUGH COLD AIR FOR THIS SYSTEM TO END AS SNOW AS THE MAIN LOW PRESSURE FEATURE MOVES NORTHEAST OVER NEW BRUNSWICK. THE POSSIBILITY OF A COUPLE INCHES OF SNOW...ESPECIALLY FROM THE SARATOGA REGION POINTS NORTH AND WEST IS POSSIBLE AS T850 AND T925 WILL BE WELL BELOW 0C ACROSS THE REGION AS WE GO PAST 00Z THURSDAY. ONE GENERAL CONSENSUS AS OF NOW BETWEEN THE MODELS IS THAT THE BEST BAROCLINICITY AND Q-VECTOR FORCING APPEARS TO BE JUST OFF THE SOUTHERN COAST OF LONG ISLAND WHERE THE MOST CONCENTRATED QPF AMOUNTS WILL BE AS THE MAIN AREA OF LOW PRESSURE MOVING NORTHEAST UP THE COASTLINE ALONG AN UPPER LEVEL WAVE OF LOW PRESSURE. THEREFORE...FOR THE START OF THE LONG TERM SECTION...VARIATIONS TO THE BAROCLINIC POSITION WITH THICKNESSES WELL ABOVE 540 DAM AT 500 HPA AHEAD OF A SECONDARY UPPER LEVEL LOW PRESSURE WAVE MOVING EAST FROM THE GREAT LAKES MAY DELAY THE CHANGEOVER FROM RAIN TO WINTRY MIX AND SNOW UNTIL MID THURSDAY MORNING. AT THIS TIME HOWEVER...THERE ARE STILL MANY VARIATIONS IN PRECIPITATION TYPES AND EVEN TEMPERATURE OUTLOOKS DURING THE EVENT SO FURTHER UPDATES WILL BE NEEDED AS WE GET CLOSER TO THE EVENT. THURSDAY NIGHT THROUGH SUNDAY...AS THE MAIN LOW PRESSURE SYSTEM EXITS THE ATLANTIC COASTLINE WELL INTO CANADA...LARGE AREA OF SUBSIDENCE WILL MOVE INTO THE REGION GIVING TRANQUIL WEATHER CONDITIONS. WITH A NORTHWESTERLY FLOW MODERATING TO A MORE WESTERLY FLOW BY SUNDAY...TEMPERATURES WILL STILL REMAIN BELOW NORMAL WITH TEMPERATURES RANGING FROM THE MID 20S TO LOWER 30S FOR FRIDAY AND SATURDAY WITH TEMPERATURES MODERATING FROM THE UPPER 20S TO MID 30S BY SUNDAY ACROSS THE ENTIRE REGION. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE 24 HOUR PERIOD ENDING 18Z MONDAY...WITH A COLD AND DRY NORTHWEST FLOW ACROSS THE AREA AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE MAIN AVIATION CONCERN CONTINUES TO BE STRONG NORTHWEST WINDS THIS AFTERNOON INTO THIS EVENING. SUSTAINED WINDS OF GENERALLY 17 TO 22 KT ARE EXPECTED...WITH GUSTS TO AROUND 30 TO 40 KTS. THE STRONGEST WINDS WILL OCCUR AT KALB AND KPSF. AFTER SUNSET WINDS SPEEDS WILL SLOWLY SUBSIDE...BUT GUSTS OF 15 TO 20 KTS WILL CONTINUE UNTIL LATE EVENING OR MIDNIGHT. WINDS WILL DECREASE FURTHER SHORTLY BEFORE SUNRISE MONDAY. OUTLOOK... MONDAY THROUGH MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUESDAY: LOW OPERATIONAL IMPACT. CHANCE OF RA. TUESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY RA...SN...IP. WEDNESDAY: MODERATE OPERATIONAL IMPACT. LIKELY RA. WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...SHSN. THANKSGIVING DAY: LOW OPERATIONAL IMPACT. BREEZY. NO SIG WX. && .HYDROLOGY... NO HYDROLOGY PROBLEMS THROUGH EARLY THIS WEEK AS ICE WILL BE BUILDING DUE TO SUB FREEZING TEMPERATURES INTO EARLY NEXT WEEK. THEREAFTER...A POTENT COASTAL STORM WILL IMPACT THE REGION WITH MODERATE TO POTENTIALLY SIGNIFICANT AMOUNTS OF WATER EQUIVALENT. THE TIME FRAME WILL BE FROM TUESDAY AFTERNOON INTO WEDNESDAY EVENING AS A COASTAL STORM COULD BRING 1.5 TO 2.5 INCHES OF LIQUID EQUIVALENT PRECIPITATION TO THE REGION /LOCALLY HIGHER IS POSSIBLE/. IT WILL BEGIN AS SNOW AND COULD LINGER AS SNOW IN THE NORTHERN MOUNTAINS...HOWEVER IN MUCH OF THE REGION IT IS EXPECTED TO CHANGE TO RAIN...RESULTING IN SIGNIFICANT WITHIN BANK RISES. IN THIS STORMS WAKE IT WILL TURN SHARPLY COLDER AGAIN WEDNESDAY NIGHT...WITH ICE FORMATION LIKELY TO BEGIN ANEW. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR CTZ001-013. NY...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ032-033- 038>043-047>054-058>061-063>066-082>084. MA...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MAZ001-025. VT...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VTZ013>015. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...LFM AVIATION...JPV HYDROLOGY...BGM FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
958 PM EST MON NOV 25 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF LOUISIANA. LOWER CLOUDS NOW BLANKETING THE ENTIRE FA. WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE HAS NOW DEVELOPED ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL THE OVERNIGHT HOURS. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET...MAINLY IN THE EXTREME NW PORTIONS OF THE FA. BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES ABOVE FREEZING...SO NO ACCUMULATION SHOULD OCCUR. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... MVFR CONDITIONS THROUGH MOST OF THE OVERNIGHT PERIOD THEN DETERIORATING TO IFR BY 12Z. HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SHIFT EAST INTO THE ATLANTIC AS LOW PRESSURE ALONG THE GULF COAST PUSHES NORTHEASTWARD. DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE APPROACHING WEATHER SYSTEM...CEILINGS HAVE LOWERED TO MVFR AT ALL TAF SITES. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 08Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. MAINLY MODERATE RAIN ON TUESDAY BUT CANNOT RULE OUT SOME HEAVY RAIN AT TIMES PARTICULARLY AT CAE/CUB. MODEL SOUNDINGS AND LOCAL SCHEME SHOWING WIND SHEAR DEVELOPING TUESDAY MORNING. INTRODUCED WIND SHEAR OF 35 KNOTS FROM 12Z TO 18Z. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
707 PM EST MON NOV 25 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF TEXAS AND LOUISIANA. LOWER CLOUDS ALREADY ENTERING THE FA FROM THE WEST. STILL COOL AND DRY CONDITIONS IN THE LOWER LAYERS. WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE IS DEVELOPING ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL LATE TONIGHT. THE 1600 GMT HRRR INDICATED AREAS OF LIGHT PRECIPITATION DEVELOPING IN THE WEST PART OF THE FORECAST AREA AROUND MIDNIGHT...WITH THE BULK OF THE PRECIPITATION ABOUT TO MOVE INTO THE WEST PART OF THE AREA AT 200 AM. USED THIS GUIDANCE FOR THE TIMING. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET. WE BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES JUST ABOVE FREEZING...NO ACCUMULATION SHOULD OCCUR. WE USED THE COOLER TEMPERATURE GUIDANCE TONIGHT BECAUSE OF THE DRY AIR IN PLACE AND EVAPORATIVE COOLING ASSOCIATED WITH THE MOISTURE INCREASE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... MVFR CONDITIONS THROUGH MOST OF TONIGHT THEN DETERIORATING TO IFR BY 09Z. HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SHIFT EAST INTO THE ATLANTIC AS LOW PRESSURE ALONG THE GULF COAST PUSHES NORTHEASTWARD. DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE APPROACHING WEATHER SYSTEM...CEILINGS HAVE LOWERED AND HAVE ALREADY DROPPED TO MVFR AT OGB/AGS/DNL. LIGHT RAIN SHOULD SPREAD INTO THE AREA AROUND 07Z-09Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 12Z-14Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. MAINLY MODERATE RAIN ON TUESDAY BUT CANNOT RULE OUT SOME HEAVY RAIN AT TIMES PARTICULARLY AT CAE/CUB. MODEL SOUNDINGS AND LOCAL SCHEME SHOWING WIND SHEAR DEVELOPING TUESDAY MORNING. INTRODUCED WIND SHEAR OF 35 KNOTS THROUGH 18Z. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
748 PM EST MON NOV 25 2013 .SYNOPSIS... ISSUED AT 340 PM EST MON NOV 25 2013 A CLIPPER SYSTEM WILL BRING LIGHT SNOW OR FLURRIES TO THE AREA THROUGH THIS EVENING...WITH ONLY MINOR ACCUMULATIONS POSSIBLE. A REINFORCING SHOT OF COLD AIR WILL SET THE STAGE FOR A POTENTIAL HEAVY LAKE EFFECT SNOW EVENT TUESDAY NIGHT THROUGH WEDNESDAY ACROSS FAR SOUTHWEST LOWER MICHIGAN AND PORTIONS OF NORTHWEST AND NORTH CENTRAL INDIANA. && .UPDATE... ISSUED AT 700 PM EST MON NOV 25 2013 LEAD SHORTWAVE APPEARS TO BE QUITE SHEARED IN NATURE STRETCHING FROM SOUTHERN LOWER MICHIGAN BACK INTO CENTRAL ILLINOIS THIS EVENING. THIS WAVE WILL CONTINUE TO SLIDE EAST THROUGH THE AREA THROUGH THE LATE EVENING. THE COMBINATION OF WEAK DPVA WITH THIS FEATURE AND ASSOCIATED DOWNSTREAM WEAK 750-650 HPA FRONTOGENESIS WILL SUPPORT AREA OF -SN OVERSPREADING MUCH OF EASTERN AND SOUTHEAST PORTIONS OF THE AREA THROUGH MIDNIGHT. DRY NATURE TO AIR MASS AND ELEVATED NATURE OF FORCING WILL ONLY LEAD TO A FEW TENTHS OF SNOW ACCUMULATION FOR MOST LOCATIONS HOWEVER. MUCH DRIER MID LEVEL AIR ADVECTING IN BEHIND THIS LEAD SHORT WAVE HAS CUT OFF PRECIP ACROSS THE FAR NORTH EARLY THIS EVENING. WATER VAPOR IMAGERY/21Z RAP INITIALIZATION DO SUGGEST PRESENCE OF NEXT UPSTREAM VORT ACROSS SOUTHERN MINNESOTA WHICH WILL SLIDE INTO THE WESTERN GREAT LAKES LATE TONIGHT. NOT COMPLETELY OUT OF THE QUESTION THAT SOME PATCHY FREEZING DRIZZLE COULD ACCOMPANY THIS WEAK FORCING...BUT GIVEN EXPECTED VERY LIGHT NATURE TO THE DRIZZLE IF IT OCCURS WOULD EXPECT MINIMAL TO NO IMPACT SO WILL CONTINUE TO OMIT FROM THE FORECAST. ONLY TWEAK TO PREVIOUS FORECAST WAS TO INCREASE POPS SLIGHTLY ACROSS CENTRAL PORTIONS OF THE AREA WHERE IT APPEARS SOME VERY WEAK ELEVATED FGEN RESPONSE HAS OCCURRED OVER THE PAST HOUR OR TWO. EVEN ACROSS THESE LOCATIONS...ACCUMULATIONS SHOULD ONLY TOTAL A TENTH OR TWO. ANOTHER WEAK WAVE FROM SOUTHERN STREAM ACROSS CENTRAL ILLINOIS EVIDENT ON WATER VAPOR IMAGERY MAY CLIP SOUTHERN PORTIONS OF FORECAST THROUGH EARLY PORTIONS OF THE OVERNIGHT THAT COULD LEAD TO BRIEF ENHANCEMENT OF WEAK ELEVATED FGEN...BUT LITTLE OR NO ACCUMULATION IS EXPECTED. TREND OF DIMINISHING POPS FROM NORTHWEST TO SOUTHEAST STILL APPEARS REASONABLE AND NO OTHER CHANGES MADE TO PREVIOUS FORECAST AT THIS TIME. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 340 PM EST MON NOV 25 2013 LEAD NORTHERN STREAM S/W CURRENTLY DIVING SOUTHEAST ACROSS UPPER GREAT LAKES. WEAK SMALLER SCALE WAVES STREAMING NORTHEAST TOWARD THE LOWER GREAT LAKES NOTED ON W/V IMAGERY THIS AFTN...EMANATING FROM STRONG SOUTHERN LOW ACROSS PANHANDLE REGION. THE PHASING OF THESE WEAKER P/V ANOMALIES ACROSS THE AREA...COMBINED WITH COMPACT CORRIDOR OF DECENT ISENTROPIC LIFT...PROVIDING WIDESPREAD PRECIPITATION ACROSS THE REGION PER RADAR. THESE SNOW SHOWERS HAVE BEEN STRUGGLING TO REACH THE GROUND ALL DAY PER UPSTREAM SFC OBS...GIVEN STOUT DRY BOUNDARY LAYER AND SFC DEWPOINT DEPRESSIONS ON THE ORDER OF 10-15F. CONTINUED WITH PREVIOUS FCST TREND...MENTIONING LIGHT SNOW WORDING/FLURRIES...ALONG WITH LIGHT ACCUMULATIONS ACROSS THE AREA. CONFIDENCE HAS WANED FOR ANY ACCUMULATIONS GIVEN RADAR TRENDS...HOWEVER STREAM OF MID LVL MOISTURE ADVECTING NE INTO THE AREA NOTED ON W/V MAY LEND TO ENHANCE THESE RETURNS AND HELP TOP DOWN SATURATION OF THE LAYER...COINCIDENT WITH THE CORRIDOR OF ISENTROPIC LIFT. CORRIDOR OF LIFT STRETCHES OFF TO THE EAST AFTER MIDNIGHT...WITH DIMINISHING POPS REFLECTED IN THE GRIDS. STRONGER NORTHERN STREAM P/V ANOMALY WILL SURGE SOUTHEAST THROUGH THE REGION ON TUESDAY...AND WILL ATTEMPT TO PHASE WITH SOUTHERN STREAM P/V ANOMALY LATE TOMORROW AND WEDNESDAY WELL SOUTHEAST OF THE REGION. ATLANTIC COAST SFC CYCLONE WILL DEVELOP IN RESPONSE TO THESE FEATURES...AND BRING WIDESPREAD PRECIP TO MUCH OF THE EASTERN US. HOWEVER...BEST ISENTROPIC UPGLIDE SHOULD KEEP SNOWFALL SOUTH AND EAST OF THE AREA THROUGH TUESDAY...ESPECIALLY GIVEN THE AGGRESSIVE NATURE OF THE NORTHERN STREAM ENERGY SURGING SOUTHEAST THROUGH THE AREA. THEREFORE...HAVE KEPT POPS OUT OF THE TUESDAY PERIOD ACROSS THE SOUTHEAST PORTION OF THE AREA...BUT HEDGED WITH A CHANCE FLURRIES MENTION CLOSE TO THE EDGE OF THE BEST MOISTURE/LIFT GRADIENTS. NO MAJOR CHANCES TO TEMPS TONIGHT/TUESDAY. ACCOMPANYING THIS STRONG NORTHERN P/V ANOMALY IS ANOTHER EARLY SEASON SURGE OF ARCTIC AIR. THIS WILL PUSH THROUGH THE AREA TUESDAY AFTERNOON. KEPT WITH A FLURRY MENTION ACROSS THE AREA IN THE AFTERNOON IN THE WAKE OF THE ARCTIC FRONT. LAKE RESPONSE SHOULD ACTIVATE TUESDAY AFTERNOON AS 850MB TEMPS CRASH TO -12C TO -13C BY 21Z TUESDAY. SHOULD BE RATHER DISORGANIZED BEFORE 00Z...AS LOW LVL NORTHWEST FLOW SHOULD KEEP BANDING TO A MINIMUM DURING THIS PERIOD. WENT WITH A FEW TENTHS OF SNOW ACCUMULATION ACROSS FAR SW LWR MI FROM 18Z TO 00Z...BEFORE FLOW VEERS NORTHERLY INTO THE OVERNIGHT...LEADING TO A SIGNIFICANT SINGLE BAND EVENT IN THE LONG TERM PERIOD. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 340 PM EST MON NOV 25 2013 ...SIGNIFICANT LAKE EFFECT SNOW EXPECTED TUE NIGHT-WED... FCST THIS AFTN PREDICATED ON SHARPER H5 SOLUTIONS ALOFT INCLUDING NAM/GEM/EC AND VARIOUS HIGHRES GUIDANCE AS POTENT SRN STREAM SW PHASES W/SECONDARY NRN STREAM DROPPING SWD THROUGH NRN SK THIS AFTN. VIGOROUS/SHARP LL CAA BURST XPCD TUE NIGHT W/DEEP NRLY LONG AXIS FETCH DVLPG. CLEAR INDICATIONS OF LK SP CONNECTION WHICH WILL MOST CERTAINLY AID IN BREATH OF LATENT MSTR FLUX AND MODULATE SNOWBAND INTENSITY HIGHER. 30-35KT MEAN CLD BEARING LYR FLW SHLD ALSO YIELD A FURTHER INLAND PENETRATION OF SNOWBANDS BUT WHERE REMAINS A BIG QN. TYPICAL W-E SPREAD NOTED THIS AFTN ALTHOUGH A DECIDED CONSENSUS LIES W/ERN CLUSTER OF SOLUTIONS INCLUDING MOST HIGHRES RENDITIONS ALG W/GEM AND 4KM NAM. AT THIS POINT GIVEN HOLIDAY TRAVEL CONCERNS WILL BROAD BRUSH A WATCH FOR LT TUE NIGHT-WED EVE ACRS MUCH OF THE WRN CORNER. HWVR IMPACTS WILL LIKELY EXTEND FARTHER DOWNSTREAM AND WILL ADDRESS IN HWO UPDATE. FVRBL DGZ LOCATION WITHIN LVL OF NON DVRG NOTED IN XSCTNS ALG W/MAXIMIZED RH AND STG ASCENT WOULD PORTEND A PD OF 1-2 INCH SNOWFALL RATES LIKELY VRY LT TUE NIGHT INTO WED AFTN BFR WKNG. CONSERVATIVE AGGREGATED QPF YIELDS A BROAD 6-10 INCH SNOW PLUME W/OBVIOUS HEAVIER ACCUMS TIED TO PLACEMENT OF LK SP CONNECTED PLUME AND LESSOR ACCUMS TIED TO WHERE WEAKER WRN DIPOLE DVLPS. BAND XPCD TO BREAKUP RAPIDLY WED EVE IN RESPONSE TO QUICK FLATTEN OF FLW ALOFT AS EAST COAST STORM LIFTS OUT AND AHD OF NXT UPSTREAM DISTURBANCE. TEMPS THROUGH THE PD CONT COLD BUT MODERATION ON TAP THIS WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 700 PM EST MON NOV 25 2013 A WEAK LEAD SHORT WAVE AND VERY WEAK MID LEVEL FRONTOGENESIS FORCING HAS ALLOWED FOR AN AREA OF LIGHT SNOW TO AFFECT NORTHERN INDIANA THIS EVENING. VSBYS/CIGS GENERALLY SHOULD REMAIN MVFR WITH PERHAPS A BRIEF PERIOD OF IFR VSBYS AT KFWA THROUGH 03Z...BUT CONFIDENCE IN OCCURRENCE IS TOO LOW FOR TAF INCLUSION AT THIS TIME. OVERALL CONFIDENCE IN CIG FORECAST IS ALSO RELATIVELY LOW OVERNIGHT GIVEN SHALLOW MOISTURE TRAPPED BENEATH DRYING MID LEVEL PROFILES...BUT DID CARRY HIGHER END MVFR CIGS AT KSBN THROUGH DAYBREAK. A MORE VIGOROUS UPPER TROUGH WILL DROP INTO THE GREAT LAKES REGION ON TUESDAY WITH AN ASSOCIATED COLD FRONTAL PASSAGE. THIS WILL RESULT IN A WIND SHIFT TO THE NORTHWEST TUESDAY WITH SOME GUSTS TO 15 TO 20 KNOTS POSSIBLE AT KSBN DURING THE AFTERNOON. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR INZ003-004-012>015. MI...LAKE EFFECT SNOW WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING FOR MIZ077. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR LMZ043-046. && $$ UPDATE...MARSILI SYNOPSIS...NG SHORT TERM...NG LONG TERM...T AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1251 AM EST SUN NOV 24 2013 .SYNOPSIS... ISSUED AT 724 PM EST SAT NOV 23 2013 A RIDGE OF HIGH PRESSURE ACCOMPANIED BY AN ARCTIC AIR MASS WILL CONTINUE TO AFFECT THE REGION THROUGH SUNDAY. THIS COLD AIR OVER THE WARMER LAKE MICHIGAN WATERS WILL RESULT IN CONTINUED LAKE EFFECT SNOW SHOWERS ACROSS SOUTHWEST LOWER MICHIGAN AND NORTH CENTRAL INDIANA THROUGH SUNDAY MORNING BEFORE DIMINISHING. SOME MORE LIGHT SNOW IS POSSIBLE MONDAY AS AN UPPER LEVEL DISTURBANCE TRACKS ACROSS THE GREAT LAKES. && .UPDATE... ISSUED AT 724 PM EST SAT NOV 23 2013 MULTI-BAND LAKE EFFECT WITH CELLULAR NATURE CONTINUES TO IMPACT SOUTHWEST LOWER MICHIGAN AND NORTH CENTRAL INDIANA THIS EVENING. FETCH CONSIDERATIONS AND EASTERN LAKE SHORE LAKE AGGREGATE TROUGHING HAVE RESULTED IN PRIMARY AREA OF CONCERN FROM EXTREME NORTHERN BERRIEN COUNTY EXTENDING SOUTHEASTWARD THROUGH SOUTHERN CASS...ELKHART...AND NORTHEAST KOSCIUSKO COUNTIES. BOUNDARY LAYER INSTABILITY AND STRENGTH OF LOW LEVEL FLOW HAS ALLOWED THESE BANDS TO PENETRATE WELL INLAND WITH BRIEF PERIODS OF 1 TO 2 INCH PER HOUR SNOWFALL RATES WITH MOST INTENSE BANDING. SUSTAINING THESE TYPE OF SNOWFALL RATES HAS BEEN PROBLEMATIC HOWEVER DUE TO MORE BROKEN...CELLULAR NATURE. OUTSIDE OF THIS MAIN BAND/STRONGEST LOW LEVEL CONVERGENCE ZONE...GENERALLY ONLY A DUSTING TO A FEW TENTHS OF AN INCH OF SNOW HAS BEEN REPORTED. ORGANIZATION HAS BEEN SOMEWHAT LOOSE OVER PAST FEW HOURS POSSIBLY TIED SOMEWHAT INTO PASSAGE OF UPPER LEVEL VORT MAX LATE AFTERNOON/EARLY EVENING. SOME SYNOPTIC CONTRIBUTION EXPECTED OVERNIGHT HOWEVER...AS WEAK SHEARED VORT MAX DOWNSTREAM OF APPROACHING RIDGE AXIS TRACKS INTO THE WESTERN GREAT LAKES. THUS...WILL NEED TO WATCH FOR SOME BETTER ORGANIZATION AS WE GET INTO THE LATE EVENING HOURS. IT STILL APPEARS AS THOUGH MAIN LIMITING FACTOR FOG SIGNIFICANT ACCUMULATIONS OVERNIGHT WILL CONTINUE TO BE VERY DRY NATURE TO THE AIRMASS. NAM/RAP BUFFER SOUNDINGS SUGGEST PEAK LAKE INDUCED INSTABILITY AROUND THE 06Z TIMEFRAME WITH FAVORABLE JUXTAPOSITION OF STRONGEST LOW LEVEL VERTICAL MOTION WITH DGZ THROUGH THE OVERNIGHT. HOWEVER...GRADUAL LOWERING OF INVERSION TOWARD MORNING MAY TAKE STRONGEST VERTICAL MOTIONS JUST BELOW CORE OF DGZ BY 12Z. GIVEN ABOVE FACTORS AND LIMITING FACTOR OF DRY LARGE SCALE AIR MASS...STILL FEEL THAT PREVIOUS FORECAST IS IN GOOD SHAPE WITH ADVISORY LEVEL ACCUMULATIONS. CONFIDENCE IN REACHING WARNING TYPE ACCUMS GIVEN CELLULAR NATURE AND GRADUAL LOWERING INVERSION HEIGHTS OVERNIGHT STILL QUITE LOW AND WILL NOT MAKE ANY CHANGES TO GOING HEADLINES. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 400 PM EST SAT NOV 23 2013 ARCTIC AIRMASS ASSOCIATED WITH 1050MB SURFACE HIGH IS CURRENTLY ENGULFING THE REGION...LEADING TO FALLING TEMPS AND A DECENT LAKE RESPONSE. 850MB TEMPS CONTINUE TO FALL INTO THE UPPER TEENS BELOW ZERO AND 700MB DELTA-T`S ARE AT OR ABOVE 30C. CERTAINLY PLENTY OF LAKE INDUCED INSTABILITY BUT DEGREE OF UPSTREAM DRY AIR AND LOW LEVEL FLOW TRAJECTORIES REMAIN A LIMITING FACTOR. AS PREVIOUSLY MENTIONED...SURFACE DEWPOINTS OVER WISCONSIN ARE HOVERING AT OR BELOW ZERO. 330 DEGREE SURFACE WINDS GIVE A DECENT FETCH ALONG LAKE MICHIGAN BUT MOISTURE AND SENSIBLE/LATENT HEAT FLUX CAN ONLY DO SO MUCH...ESPECIALLY GIVEN STRONG GRADIENT AND MARGINAL UPSTREAM PRECONDITIONING FROM WESTERN LAKE SUPERIOR. THIS IS BORNE OUT BY RELATIVELY DRY NEAR SURFACE PROFILES ON FORECAST SOUNDINGS AND CEILINGS GENERALLY ABOVE 3 KFT DURING THE DAY TODAY. DRY AIR ALOFT IS ALSO PREVENTING CONVECTIVE DEPTHS FROM GETTING MUCH ABOVE 7 KFT...PER NAM AND RAP FORECAST SOUNDINGS. APPEARS TO BE SOME SEMBLANCE OF FRICTIONAL CONVERGENCE OR THERMALLY-INDUCED PRESSURE TROUGHING ALONG THE EASTERN SHORE OF LAKE MICHIGAN BUT STRONG NORTHWEST GRADIENT IS DISRUPTING THE FORMATION OF A SINGLE DOMINANT BAND AND HEAVIER SNOW SHOWERS HAVE BEEN FAIRLY SPORADIC AND DISORGANIZED THROUGHOUT THE DAY. 12Z HI-RES GUIDANCE SUGGESTS BANDS MAY BECOME A LITTLE BETTER ORGANIZED OVERNIGHT BUT THE AFOREMENTIONED LIMITING FACTORS WILL REMAIN LARGELY IN PLACE THROUGH THE MORNING WITH A STIFF NORTHWEST WIND...PERSISTENT SYNOPTIC-SCALE DRY AIR ADVECTION...AND A WELL MIXED BOUNDARY LAYER. STRONG INSTABILITY...LONG DURATION...AND NEARLY IDEAL DGZ PLACEMENT WILL CONTINUE TO AT LEAST PARTIALLY OFFSET THOSE NEGATIVE FACTORS THOUGH AND WILL CONTINUE TO SEE SPURTS OF HEAVIER SNOW SHOWERS THROUGH TOMORROW MORNING THAT COULD EVENTUALLY ADD UP TO 3-5 INCHES IN THE ADVISORY AREA. STILL DONT EXPECT WARNING CRITERIA SNOWFALL. THE ONLY POSSIBLE EXCEPTION MAY BE IN CASS COUNTY MI WHERE 5-8 INCHES MAY BE POSSIBLE IF A MORE ORGANIZED/FOCUSED BAND DEVELOPS BUT CONFIDENCE IN THIS OCCURRING IS TOO LOW TO WARRANT AN UPGRADE AT THIS POINT. BACKING LOW LEVEL WINDS AND PERSISTENT SUBSIDENCE/DRY AIR ADVECTION WILL BRING AN END TO LAKE AFFECT SNOW SHOWERS AROUND MIDDAY TOMORROW. OTHER MAIN STORY DURING THIS SHORT TERM PERIOD WILL BE THE VERY COLD TEMPERATURES. STRONG GRADIENT AND LAKE INDUCED CLOUD COVER WILL PREVENT ANY DECOUPLING OR RADIATIVE COOLING OVERNIGHT FOR MOST OF OUR CWA BUT VERY COLD THERMAL PROFILES ADVECTING INTO THE AREA WILL STILL SUPPORT LOWS GENERALLY IN THE MID TEENS. COMBINED WITH THE WIND...IT WILL FEEL LIKE THE LOW SINGLE DIGITS IN SOME AREAS. HIGHS TOMORROW WILL STRUGGLE TO GET OUT OF THE MID 20S GIVEN 925MB TEMPS STILL AROUND -11C. MODELS CONTINUE TO STRUGGLE WITH THE MAGNITUDE OF THIS COLD AIRMASS AND HAVE CONTINUED TO LEAN ON THE COOLER SIDE OF GUIDANCE. && .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 400 PM EST SAT NOV 23 2013 PREFERENCE THIS AFTN LIES W/SHARPER H5 EVOLUTION ALOFT MID PD IN RESPONSE TO EWD EJECTION OF STG SRN STREAM SW UNDERNEATH AMPLIFYING NRN STREAM ACRS THE WRN LAKES WHICH PROVIDES A PATHWAY FOR SOME XPCD PHASING ALOFT. AS SUCH AND IN TANDEM W/GEM/NAM/EC TRENDS...BUMPED POPS CONSIDERABLY WED-THU FOR WHAT SHLD BE A SIG LK EFFECT SNOW EVENT AS YET ANOTHER SURGE OF COLD CANADIAN AIR FUNNELS SWD ACRS THE LAKES. STEEP NW FLW ALOFT CONTS THROUGH THE END OF THE PD W/PROMISE OF CONTD WELL BLO NORMAL TEMPS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1243 AM EST SUN NOV 24 2013 PRIMARY LES BAND SHOULD REMAIN JUST N-E OF KSBN AIRFIELD FOR REMNDR OF AM HOURS. LESSER ORGANIZED BAND TO WEST WITH LWR 30 DBZ RETURNS TO SLIDE INTO KSBN OFF/ON NEXT FEW HOURS. THEREAFTER DERISION OF DRY AIRMASS FM BENEATH AND LOWERING SUBSIDENCE INVERSION LEADING TO THINNING MSTR LAYER WITH POTNL FOR FUEL ALT CONDS BECOMING TOO LOW FOR MENTION BYND 09 UTC. WEAKENING RETURNS ON SOUTHERN PERIPHERY OF PRIMARY BAND SHOULD LEAD TO OCNL MINOR VSBY REDUCTIONS AT KFWA AS WELL...THOUGH INLAND SUSTENANCE SUCH THAT VFR MET CONDS EXPECTED TO DOMINATE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ004>006. MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ077>079. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046. && $$ UPDATE...MARSILI SYNOPSIS...MARSILI SHORT TERM...AGD LONG TERM...T AVIATION...MURPHY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1136 AM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 1132 AM MST SUN NOV 24 2013 AXIS OF STRONG WINDS HAS DEVELOPED A BIT FARTHER SOUTH THAN PREVIOUSLY EXPECTED...WITH BREAK IN CLOUDS ALLOWING DEEPER MIXING TO OCCUR AS FAR SOUTH AS TRB RESULTING IN WINDS QUICKLY APPROACHING ADVISORY LEVELS AND HAVE EXPANDED ADVISORY TO THE SOUTH IN RESPONSE. UPDATE ISSUED AT 904 AM MST SUN NOV 24 2013 WIND GUSTS OF 38 KTS AT LAA AND 41 KTS AT ITR IN THE LAST HOUR INDICATE BOUNDARY LAYER BEGINNING TO TAP INTO STRONG JET OF LOW LEVEL WINDS AS PER LATEST RAP AND KGLD VWP. AM A LITTLE CONCERNED ABOUT AREA OF 50KTS OVER EASTERN COLORADO AT 1 KM AGL...BUT THAT IS EXPECTED TO WEAKEN OVER THE NEXT 2 HOURS SO DO NOT ANTICIPATE THE NEED FOR A HIGH WIND WARNING. A WIND ADVISORY DOES APPEAR NECESSARY AND HAVE ISSUED ONE BASICALLY FOLLOWING EXPECTED CORE OF STRONGEST 1 KM AGL WINDS THE NEXT FEW HOURS...WITH WINDS EXPECTED TO DIMINISH IN THE AFTERNOON. MAY SEE SNOW SHOWERS MAKE IT INTO THIS AREA OF STRONG WINDS...BUT THINK INTENSITY AND DURATION DOES NOT WARRANT ANY KIND OF PREDOMINANT BLOWING SNOW ADVISORY. && .SHORT TERM...(TODAY AND TUESDAY NIGHT) ISSUED AT 149 AM MST SUN NOV 24 2013 THE UPPER LEVEL LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE FORECAST AREA WILL MOVE SLOWLY ACROSS THE DESERT SOUTHWEST AND SOUTHERN ROCKIES TODAY. AHEAD OF THIS SYSTEM...LIGHT SNOW WILL SPREAD NORTHWARD OUT OF EASTERN NEW MEXICO AND THE PANHANDLE REGION OF TEXAS AND OKLAHOMA INTO PORTIONS OF EASTERN COLORADO AND WESTERN KANSAS. THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL BE THIS MORNING MAINLY ALONG AND SOUTH OF INTERSTATE 70 WHERE AN INCH OR LESS OF TOTAL ACCUMULATION IS POSSIBLE. THE UPPER LOW CENTER WILL PHASE INTO THE MAIN UPPER TROUGH THAT DEEPENS OVER THE GREAT LAKES AND MISSISSIPPI VALLEY REGION TONIGHT. THE LOW WILL THEN BEGIN TO MOVE SOUTHEASTWARD OVER TEXAS WITH DRYER AIR ALOFT AND SUBSIDENCE MOVING OVER THE CENTRAL HIGH PLAINS REGION TONIGHT. THE UPPER RIDGE AMPLIFYING OVER THE WESTERN UNITED STATES MOVES OVER THE INTERMOUNTAIN REGION MONDAY NIGHT AND TUESDAY AND BEGINS TO MOVE OVER THE ROCKIES ON TUESDAY NIGHT. ALTHOUGH TEMPERATURES WILL BE GRADUALLY INCREASING THROUGH THE FIRST PART OF THE WORK WEEK AS HIGH PRESSURE MOVES INTO THE REGION...MODEL TRENDS HAVE BEEN CONSISTENTLY LOWERING TEMPERATURES WITH EACH SUBSEQUENT MODEL RUN OVER THE PAST FEW DAYS. TEMPERATURES WILL REMAIN COLDER THAN AVERAGE WITH DRY CONDITIONS EXPECTED. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 149 AM MST SUN NOV 24 2013 THE LARGE SCALE PATTERN SHOWS A LONGWAVE TROUGH OVER THE EASTERN PORTION OF THE U.S. WITH AN UPPER RIDGE OVER THE ROCKIES. THROUGHOUT THE EXTENDED...SEVERAL SHORTWAVE TROUGHS IN THE NORTHWEST/WESTERLY FLOW ALOFT MOVE THROUGH THE NORTHERN PLAINS...SENDING A FEW WEAK COLD FRONTS THROUGH THE CWA. THE COLD AIR BEHIND THE FIRST FRONT IS KEPT WELL TO THE NORTH...SO TEMPERATURES ARE NOT EXPECTED TO FLUCTUATE MUCH BEHIND THE FRONTAL PASSAGE. THE FIRST FRONT MOVES THROUGH WEDNESDAY NIGHT INTO THURSDAY AND THE NEXT FRONT...ASSOCIATED WITH WESTERLY/SOUTHWEST FLOW ALOFT...MOVES THROUGH FRIDAY NIGHT INTO SATURDAY. TEMPERATURES WITH THE NEXT FRONTAL PASSAGE ALSO ARE NOT EXPECTED TO FLUCTUATE MUCH SINCE HIGHS SHOULD RECOVER AS THE SURFACE HIGH QUICKLY PUSHES EAST BY SATURDAY AFTERNOON. FRONTAL PASSAGES WILL ALSO REMAIN DRY AS THE MAIN FORCING WITH THESE WAVES ALSO REMAINS NORTH OF THE CWA. TOWARDS THE END OF THE PERIOD...THE LARGE SCALE PATTERN SHIFTS EAST WITH THE RIDGE FLATTENING AND MOVING OVER THE CWA THURSDAY THROUGH SATURDAY...WHILE A CLOSED UPPER LOW REMAINS OVER SOUTHERN CALIFORNIA AND SLOWLY MOVES EAST/SOUTHEAST WITH THE SOUTHERN STREAM JET MOVING OVER THE CWA ON SATURDAY. AS PREVIOUSLY MENTIONED...THE EXTENDED PERIOD SHOULD REMAIN DRY...WITH INCREASING MID TO HIGH CLOUDS WITH FRONTAL PASSAGES. TEMPERATURES SHOULD REMAIN SEASONABLE...WITH HIGHS IN THE MID 40S TO LOW 50S AND LOWS IN THE 20S. ONCE EXCEPTION FOR HIGH TEMPERATURES WILL BE WEDNESDAY...AS SURFACE HIGH PRESSURE OVER EASTERN KANSAS EXTENDS INTO THE EASTERN PORTION OF THE CWA...FROM RED WILLOW TO GOVE COUNTY AND EASTWARD...HIGHS COULD ONLY REACH THE UPPER 30S TO LOW 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1034 AM MST SUN NOV 24 2013 VFR CONDITIONS EXPECTED FOR THE PERIOD WITH MAIN CONCERN BEING STRONG SOUTHERLY WINDS ALONG THE KS AND CO BORDER. GLD WILL CONTINUE TO SEE SUSTAINED WINDS BETWEEN 22 AND 27 KTS WITH GUSTS TO 4O KTS THROUGH THE NEXT FEW HOURS BEFORE WINDS GRADUALLY DIMINISH. MCK MAY SEE A BRIEF PERIOD OF GUSTY WINDS...BUT THAT IS EXPECTED TO BE SHORT LIVED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...WIND ADVISORY UNTIL 4 PM MST /5 PM CST/ THIS AFTERNOON FOR KSZ001-013-027-041. CO...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR COZ090>092. NE...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR NEZ079. && $$ UPDATE...JRM SHORT TERM...LOCKHART LONG TERM...ALW AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1039 AM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 904 AM MST SUN NOV 24 2013 WIND GUSTS OF 38 KTS AT LAA AND 41 KTS AT ITR IN THE LAST HOUR INDICATE BOUNDARY LAYER BEGINNING TO TAP INTO STRONG JET OF LOW LEVEL WINDS AS PER LATEST RAP AND KGLD VWP. AM A LITTLE CONCERNED ABOUT AREA OF 50KTS OVER EASTERN COLORADO AT 1 KM AGL...BUT THAT IS EXPECTED TO WEAKEN OVER THE NEXT 2 HOURS SO DO NOT ANTICIPATE THE NEED FOR A HIGH WIND WARNING. A WIND ADVISORY DOES APPEAR NECESSARY AND HAVE ISSUED ONE BASICALLY FOLLOWING EXPECTED CORE OF STRONGEST 1 KM AGL WINDS THE NEXT FEW HOURS...WITH WINDS EXPECTED TO DIMINISH IN THE AFTERNOON. MAY SEE SNOW SHOWERS MAKE IT INTO THIS AREA OF STRONG WINDS...BUT THINK INTENSITY AND DURATION DOES NOT WARRANT ANY KIND OF PREDOMINANT BLOWING SNOW ADVISORY. && .SHORT TERM...(TODAY AND TUESDAY NIGHT) ISSUED AT 149 AM MST SUN NOV 24 2013 THE UPPER LEVEL LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE FORECAST AREA WILL MOVE SLOWLY ACROSS THE DESERT SOUTHWEST AND SOUTHERN ROCKIES TODAY. AHEAD OF THIS SYSTEM...LIGHT SNOW WILL SPREAD NORTHWARD OUT OF EASTERN NEW MEXICO AND THE PANHANDLE REGION OF TEXAS AND OKLAHOMA INTO PORTIONS OF EASTERN COLORADO AND WESTERN KANSAS. THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL BE THIS MORNING MAINLY ALONG AND SOUTH OF INTERSTATE 70 WHERE AN INCH OR LESS OF TOTAL ACCUMULATION IS POSSIBLE. THE UPPER LOW CENTER WILL PHASE INTO THE MAIN UPPER TROUGH THAT DEEPENS OVER THE GREAT LAKES AND MISSISSIPPI VALLEY REGION TONIGHT. THE LOW WILL THEN BEGIN TO MOVE SOUTHEASTWARD OVER TEXAS WITH DRYER AIR ALOFT AND SUBSIDENCE MOVING OVER THE CENTRAL HIGH PLAINS REGION TONIGHT. THE UPPER RIDGE AMPLIFYING OVER THE WESTERN UNITED STATES MOVES OVER THE INTERMOUNTAIN REGION MONDAY NIGHT AND TUESDAY AND BEGINS TO MOVE OVER THE ROCKIES ON TUESDAY NIGHT. ALTHOUGH TEMPERATURES WILL BE GRADUALLY INCREASING THROUGH THE FIRST PART OF THE WORK WEEK AS HIGH PRESSURE MOVES INTO THE REGION...MODEL TRENDS HAVE BEEN CONSISTENTLY LOWERING TEMPERATURES WITH EACH SUBSEQUENT MODEL RUN OVER THE PAST FEW DAYS. TEMPERATURES WILL REMAIN COLDER THAN AVERAGE WITH DRY CONDITIONS EXPECTED. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 149 AM MST SUN NOV 24 2013 THE LARGE SCALE PATTERN SHOWS A LONGWAVE TROUGH OVER THE EASTERN PORTION OF THE U.S. WITH AN UPPER RIDGE OVER THE ROCKIES. THROUGHOUT THE EXTENDED...SEVERAL SHORTWAVE TROUGHS IN THE NORTHWEST/WESTERLY FLOW ALOFT MOVE THROUGH THE NORTHERN PLAINS...SENDING A FEW WEAK COLD FRONTS THROUGH THE CWA. THE COLD AIR BEHIND THE FIRST FRONT IS KEPT WELL TO THE NORTH...SO TEMPERATURES ARE NOT EXPECTED TO FLUCTUATE MUCH BEHIND THE FRONTAL PASSAGE. THE FIRST FRONT MOVES THROUGH WEDNESDAY NIGHT INTO THURSDAY AND THE NEXT FRONT...ASSOCIATED WITH WESTERLY/SOUTHWEST FLOW ALOFT...MOVES THROUGH FRIDAY NIGHT INTO SATURDAY. TEMPERATURES WITH THE NEXT FRONTAL PASSAGE ALSO ARE NOT EXPECTED TO FLUCTUATE MUCH SINCE HIGHS SHOULD RECOVER AS THE SURFACE HIGH QUICKLY PUSHES EAST BY SATURDAY AFTERNOON. FRONTAL PASSAGES WILL ALSO REMAIN DRY AS THE MAIN FORCING WITH THESE WAVES ALSO REMAINS NORTH OF THE CWA. TOWARDS THE END OF THE PERIOD...THE LARGE SCALE PATTERN SHIFTS EAST WITH THE RIDGE FLATTENING AND MOVING OVER THE CWA THURSDAY THROUGH SATURDAY...WHILE A CLOSED UPPER LOW REMAINS OVER SOUTHERN CALIFORNIA AND SLOWLY MOVES EAST/SOUTHEAST WITH THE SOUTHERN STREAM JET MOVING OVER THE CWA ON SATURDAY. AS PREVIOUSLY MENTIONED...THE EXTENDED PERIOD SHOULD REMAIN DRY...WITH INCREASING MID TO HIGH CLOUDS WITH FRONTAL PASSAGES. TEMPERATURES SHOULD REMAIN SEASONABLE...WITH HIGHS IN THE MID 40S TO LOW 50S AND LOWS IN THE 20S. ONCE EXCEPTION FOR HIGH TEMPERATURES WILL BE WEDNESDAY...AS SURFACE HIGH PRESSURE OVER EASTERN KANSAS EXTENDS INTO THE EASTERN PORTION OF THE CWA...FROM RED WILLOW TO GOVE COUNTY AND EASTWARD...HIGHS COULD ONLY REACH THE UPPER 30S TO LOW 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1034 AM MST SUN NOV 24 2013 VFR CONDITIONS EXPECTED FOR THE PERIOD WITH MAIN CONCERN BEING STRONG SOUTHERLY WINDS ALONG THE KS AND CO BORDER. GLD WILL CONTINUE TO SEE SUSTAINED WINDS BETWEEN 22 AND 27 KTS WITH GUSTS TO 4O KTS THROUGH THE NEXT FEW HOURS BEFORE WINDS GRADUALLY DIMINISH. MCK MAY SEE A BRIEF PERIOD OF GUSTY WINDS...BUT THAT IS EXPECTED TO BE SHORT LIVED. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...WIND ADVISORY UNTIL 4 PM MST /5 PM CST/ THIS AFTERNOON FOR KSZ001-013. CO...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR COZ090>092. NE...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR NEZ079. && $$ UPDATE...JRM SHORT TERM...LOCKHART LONG TERM...ALW AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
909 AM MST SUN NOV 24 2013 .UPDATE... ISSUED AT 904 AM MST SUN NOV 24 2013 WIND GUSTS OF 38 KTS AT LAA AND 41 KTS AT ITR IN THE LAST HOUR INDICATE BOUNDARY LAYER BEGINNING TO TAP INTO STRONG JET OF LOW LEVEL WINDS AS PER LATEST RAP AND KGLD VWP. AM A LITTLE CONCERNED ABOUT AREA OF 50KTS OVER EASTERN COLORADO AT 1 KM AGL...BUT THAT IS EXPECTED TO WEAKEN OVER THE NEXT 2 HOURS SO DO NOT ANTICIPATE THE NEED FOR A HIGH WIND WARNING. A WIND ADVISORY DOES APPEAR NECESSARY AND HAVE ISSUED ONE BASICALLY FOLLOWING EXPECTED CORE OF STRONGEST 1 KM AGL WINDS THE NEXT FEW HOURS...WITH WINDS EXPECTED TO DIMINISH IN THE AFTERNOON. MAY SEE SNOW SHOWERS MAKE IT INTO THIS AREA OF STRONG WINDS...BUT THINK INTENSITY AND DURATION DOES NOT WARRANT ANY KIND OF PREDOMINANT BLOWING SNOW ADVISORY. && .SHORT TERM...(TODAY AND TUESDAY NIGHT) ISSUED AT 149 AM MST SUN NOV 24 2013 THE UPPER LEVEL LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE FORECAST AREA WILL MOVE SLOWLY ACROSS THE DESERT SOUTHWEST AND SOUTHERN ROCKIES TODAY. AHEAD OF THIS SYSTEM...LIGHT SNOW WILL SPREAD NORTHWARD OUT OF EASTERN NEW MEXICO AND THE PANHANDLE REGION OF TEXAS AND OKLAHOMA INTO PORTIONS OF EASTERN COLORADO AND WESTERN KANSAS. THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL BE THIS MORNING MAINLY ALONG AND SOUTH OF INTERSTATE 70 WHERE AN INCH OR LESS OF TOTAL ACCUMULATION IS POSSIBLE. THE UPPER LOW CENTER WILL PHASE INTO THE MAIN UPPER TROUGH THAT DEEPENS OVER THE GREAT LAKES AND MISSISSIPPI VALLEY REGION TONIGHT. THE LOW WILL THEN BEGIN TO MOVE SOUTHEASTWARD OVER TEXAS WITH DRYER AIR ALOFT AND SUBSIDENCE MOVING OVER THE CENTRAL HIGH PLAINS REGION TONIGHT. THE UPPER RIDGE AMPLIFYING OVER THE WESTERN UNITED STATES MOVES OVER THE INTERMOUNTAIN REGION MONDAY NIGHT AND TUESDAY AND BEGINS TO MOVE OVER THE ROCKIES ON TUESDAY NIGHT. ALTHOUGH TEMPERATURES WILL BE GRADUALLY INCREASING THROUGH THE FIRST PART OF THE WORK WEEK AS HIGH PRESSURE MOVES INTO THE REGION...MODEL TRENDS HAVE BEEN CONSISTENTLY LOWERING TEMPERATURES WITH EACH SUBSEQUENT MODEL RUN OVER THE PAST FEW DAYS. TEMPERATURES WILL REMAIN COLDER THAN AVERAGE WITH DRY CONDITIONS EXPECTED. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 149 AM MST SUN NOV 24 2013 THE LARGE SCALE PATTERN SHOWS A LONGWAVE TROUGH OVER THE EASTERN PORTION OF THE U.S. WITH AN UPPER RIDGE OVER THE ROCKIES. THROUGHOUT THE EXTENDED...SEVERAL SHORTWAVE TROUGHS IN THE NORTHWEST/WESTERLY FLOW ALOFT MOVE THROUGH THE NORTHERN PLAINS...SENDING A FEW WEAK COLD FRONTS THROUGH THE CWA. THE COLD AIR BEHIND THE FIRST FRONT IS KEPT WELL TO THE NORTH...SO TEMPERATURES ARE NOT EXPECTED TO FLUCTUATE MUCH BEHIND THE FRONTAL PASSAGE. THE FIRST FRONT MOVES THROUGH WEDNESDAY NIGHT INTO THURSDAY AND THE NEXT FRONT...ASSOCIATED WITH WESTERLY/SOUTHWEST FLOW ALOFT...MOVES THROUGH FRIDAY NIGHT INTO SATURDAY. TEMPERATURES WITH THE NEXT FRONTAL PASSAGE ALSO ARE NOT EXPECTED TO FLUCTUATE MUCH SINCE HIGHS SHOULD RECOVER AS THE SURFACE HIGH QUICKLY PUSHES EAST BY SATURDAY AFTERNOON. FRONTAL PASSAGES WILL ALSO REMAIN DRY AS THE MAIN FORCING WITH THESE WAVES ALSO REMAINS NORTH OF THE CWA. TOWARDS THE END OF THE PERIOD...THE LARGE SCALE PATTERN SHIFTS EAST WITH THE RIDGE FLATTENING AND MOVING OVER THE CWA THURSDAY THROUGH SATURDAY...WHILE A CLOSED UPPER LOW REMAINS OVER SOUTHERN CALIFORNIA AND SLOWLY MOVES EAST/SOUTHEAST WITH THE SOUTHERN STREAM JET MOVING OVER THE CWA ON SATURDAY. AS PREVIOUSLY MENTIONED...THE EXTENDED PERIOD SHOULD REMAIN DRY...WITH INCREASING MID TO HIGH CLOUDS WITH FRONTAL PASSAGES. TEMPERATURES SHOULD REMAIN SEASONABLE...WITH HIGHS IN THE MID 40S TO LOW 50S AND LOWS IN THE 20S. ONCE EXCEPTION FOR HIGH TEMPERATURES WILL BE WEDNESDAY...AS SURFACE HIGH PRESSURE OVER EASTERN KANSAS EXTENDS INTO THE EASTERN PORTION OF THE CWA...FROM RED WILLOW TO GOVE COUNTY AND EASTWARD...HIGHS COULD ONLY REACH THE UPPER 30S TO LOW 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 440 AM MST SUN NOV 24 2013 CURRENTLY IT LOOKS LIKE VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. CEILINGS AT KGLD ONLY REDUCED TO BKN060 IN THE LAST FEW HOURS AS THE FIRST WEAK BAND OF LIGHT SNOW MOVED OVER THE TAF SITE. SOUNDINGS EARLIER THIS MORNING INDICATED POSSIBLY LOWER CEILINGS WITH A CONTINUING CHANCE OF LIGHT SNOW LATER THIS MORNING. AFTER VIEWING RAP SOUNDINGS...IT APPEARS THAT THIS IS NO LONGER THE CASE. GUIDANCE ALSO DID NOT INCLUDE LOWERED CEILINGS BEYOND VFR. LOW CONFIDENCE IN THE FORECAST AS OF RIGHT NOW...WILL MAKE ANY AMMENDMENTS IF AND WHEN NECESSARY. SOUTHERLY WINDS WILL PICK UP TODAY TO AROUND 15 TO 25 KTS GUSTING FROM 25 TO 35 KTS. WIND GUSTS SHOULD DIMINISH OVERNIGHT WITH A WIND SHIFT TO THE NORTHWEST. OVERCAST AND BROKEN CEILINGS SHOULD BECOME SCATTERED OVERNIGHT AS THE THE STORM SYSTEM SOUTH OF THE AREA MOVES NORTH/NORTHEAST. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...WIND ADVISORY UNTIL 4 PM MST /5 PM CST/ THIS AFTERNOON FOR KSZ001-013. CO...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR COZ090>092. NE...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR NEZ079. && $$ UPDATE...JRM SHORT TERM...LOCKHART LONG TERM...ALW AVIATION...ALW
AREA FORECAST DISCUSSION
NWS GOODLAND KS
451 AM MST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TUESDAY NIGHT) ISSUED AT 149 AM MST SUN NOV 24 2013 THE UPPER LEVEL LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE FORECAST AREA WILL MOVE SLOWLY ACROSS THE DESERT SOUTHWEST AND SOUTHERN ROCKIES TODAY. AHEAD OF THIS SYSTEM...LIGHT SNOW WILL SPREAD NORTHWARD OUT OF EASTERN NEW MEXICO AND THE PANHANDLE REGION OF TEXAS AND OKLAHOMA INTO PORTIONS OF EASTERN COLORADO AND WESTERN KANSAS. THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL BE THIS MORNING MAINLY ALONG AND SOUTH OF INTERSTATE 70 WHERE AN INCH OR LESS OF TOTAL ACCUMULATION IS POSSIBLE. THE UPPER LOW CENTER WILL PHASE INTO THE MAIN UPPER TROUGH THAT DEEPENS OVER THE GREAT LAKES AND MISSISSIPPI VALLEY REGION TONIGHT. THE LOW WILL THEN BEGIN TO MOVE SOUTHEASTWARD OVER TEXAS WITH DRYER AIR ALOFT AND SUBSIDENCE MOVING OVER THE CENTRAL HIGH PLAINS REGION TONIGHT. THE UPPER RIDGE AMPLIFYING OVER THE WESTERN UNITED STATES MOVES OVER THE INTERMOUNTAIN REGION MONDAY NIGHT AND TUESDAY AND BEGINS TO MOVE OVER THE ROCKIES ON TUESDAY NIGHT. ALTHOUGH TEMPERATURES WILL BE GRADUALLY INCREASING THROUGH THE FIRST PART OF THE WORK WEEK AS HIGH PRESSURE MOVES INTO THE REGION...MODEL TRENDS HAVE BEEN CONSISTENTLY LOWERING TEMPERATURES WITH EACH SUBSEQUENT MODEL RUN OVER THE PAST FEW DAYS. TEMPERATURES WILL REMAIN COLDER THAN AVERAGE WITH DRY CONDITIONS EXPECTED. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 149 AM MST SUN NOV 24 2013 THE LARGE SCALE PATTERN SHOWS A LONGWAVE TROUGH OVER THE EASTERN PORTION OF THE U.S. WITH AN UPPER RIDGE OVER THE ROCKIES. THROUGHOUT THE EXTENDED...SEVERAL SHORTWAVE TROUGHS IN THE NORTHWEST/WESTERLY FLOW ALOFT MOVE THROUGH THE NORTHERN PLAINS...SENDING A FEW WEAK COLD FRONTS THROUGH THE CWA. THE COLD AIR BEHIND THE FIRST FRONT IS KEPT WELL TO THE NORTH...SO TEMPERATURES ARE NOT EXPECTED TO FLUCTUATE MUCH BEHIND THE FRONTAL PASSAGE. THE FIRST FRONT MOVES THROUGH WEDNESDAY NIGHT INTO THURSDAY AND THE NEXT FRONT...ASSOCIATED WITH WESTERLY/SOUTHWEST FLOW ALOFT...MOVES THROUGH FRIDAY NIGHT INTO SATURDAY. TEMPERATURES WITH THE NEXT FRONTAL PASSAGE ALSO ARE NOT EXPECTED TO FLUCTUATE MUCH SINCE HIGHS SHOULD RECOVER AS THE SURFACE HIGH QUICKLY PUSHES EAST BY SATURDAY AFTERNOON. FRONTAL PASSAGES WILL ALSO REMAIN DRY AS THE MAIN FORCING WITH THESE WAVES ALSO REMAINS NORTH OF THE CWA. TOWARDS THE END OF THE PERIOD...THE LARGE SCALE PATTERN SHIFTS EAST WITH THE RIDGE FLATTENING AND MOVING OVER THE CWA THURSDAY THROUGH SATURDAY...WHILE A CLOSED UPPER LOW REMAINS OVER SOUTHERN CALIFORNIA AND SLOWLY MOVES EAST/SOUTHEAST WITH THE SOUTHERN STREAM JET MOVING OVER THE CWA ON SATURDAY. AS PREVIOUSLY MENTIONED...THE EXTENDED PERIOD SHOULD REMAIN DRY...WITH INCREASING MID TO HIGH CLOUDS WITH FRONTAL PASSAGES. TEMPERATURES SHOULD REMAIN SEASONABLE...WITH HIGHS IN THE MID 40S TO LOW 50S AND LOWS IN THE 20S. ONCE EXCEPTION FOR HIGH TEMPERATURES WILL BE WEDNESDAY...AS SURFACE HIGH PRESSURE OVER EASTERN KANSAS EXTENDS INTO THE EASTERN PORTION OF THE CWA...FROM RED WILLOW TO GOVE COUNTY AND EASTWARD...HIGHS COULD ONLY REACH THE UPPER 30S TO LOW 40S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 440 AM MST SUN NOV 24 2013 CURRENTLY IT LOOKS LIKE VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. CEILINGS AT KGLD ONLY REDUCED TO BKN060 IN THE LAST FEW HOURS AS THE FIRST WEAK BAND OF LIGHT SNOW MOVED OVER THE TAF SITE. SOUNDINGS EARLIER THIS MORNING INDICATED POSSIBLY LOWER CEILINGS WITH A CONTINUING CHANCE OF LIGHT SNOW LATER THIS MORNING. AFTER VIEWING RAP SOUNDINGS...IT APPEARS THAT THIS IS NO LONGER THE CASE. GUIDANCE ALSO DID NOT INCLUDE LOWERED CEILINGS BEYOND VFR. LOW CONFIDENCE IN THE FORECAST AS OF RIGHT NOW...WILL MAKE ANY AMMENDMENTS IF AND WHEN NECESSARY. SOUTHERLY WINDS WILL PICK UP TODAY TO AROUND 15 TO 25 KTS GUSTING FROM 25 TO 35 KTS. WIND GUSTS SHOULD DIMINISH OVERNIGHT WITH A WIND SHIFT TO THE NORTHWEST. OVERCAST AND BROKEN CEILINGS SHOULD BECOME SCATTERED OVERNIGHT AS THE THE STORM SYSTEM SOUTH OF THE AREA MOVES NORTH/NORTHEAST. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...LOCKHART LONG TERM...ALW AVIATION...ALW
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 AM MST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TUESDAY NIGHT) ISSUED AT 149 AM MST SUN NOV 24 2013 THE UPPER LEVEL LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE FORECAST AREA WILL MOVE SLOWLY ACROSS THE DESERT SOUTHWEST AND SOUTHERN ROCKIES TODAY. AHEAD OF THIS SYSTEM...LIGHT SNOW WILL SPREAD NORTHWARD OUT OF EASTERN NEW MEXICO AND THE PANHANDLE REGION OF TEXAS AND OKLAHOMA INTO PORTIONS OF EASTERN COLORADO AND WESTERN KANSAS. THE BEST CHANCE OF ACCUMULATING SNOWFALL WILL BE THIS MORNING MAINLY ALONG AND SOUTH OF INTERSTATE 70 WHERE AN INCH OR LESS OF TOTAL ACCUMULATION IS POSSIBLE. THE UPPER LOW CENTER WILL PHASE INTO THE MAIN UPPER TROUGH THAT DEEPENS OVER THE GREAT LAKES AND MISSISSIPPI VALLEY REGION TONIGHT. THE LOW WILL THEN BEGIN TO MOVE SOUTHEASTWARD OVER TEXAS WITH DRYER AIR ALOFT AND SUBSIDENCE MOVING OVER THE CENTRAL HIGH PLAINS REGION TONIGHT. THE UPPER RIDGE AMPLIFYING OVER THE WESTERN UNITED STATES MOVES OVER THE INTERMOUNTAIN REGION MONDAY NIGHT AND TUESDAY AND BEGINS TO MOVE OVER THE ROCKIES ON TUESDAY NIGHT. ALTHOUGH TEMPERATURES WILL BE GRADUALLY INCREASING THROUGH THE FIRST PART OF THE WORK WEEK AS HIGH PRESSURE MOVES INTO THE REGION...MODEL TRENDS HAVE BEEN CONSISTENTLY LOWERING TEMPERATURES WITH EACH SUBSEQUENT MODEL RUN OVER THE PAST FEW DAYS. TEMPERATURES WILL REMAIN COLDER THAN AVERAGE WITH DRY CONDITIONS EXPECTED. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 149 AM MST SUN NOV 24 2013 THE LARGE SCALE PATTERN SHOWS A LONGWAVE TROUGH OVER THE EASTERN PORTION OF THE U.S. WITH AN UPPER RIDGE OVER THE ROCKIES. THROUGHOUT THE EXTENDED...SEVERAL SHORTWAVE TROUGHS IN THE NORTHWEST/WESTERLY FLOW ALOFT MOVE THROUGH THE NORTHERN PLAINS...SENDING A FEW WEAK COLD FRONTS THROUGH THE CWA. THE COLD AIR BEHIND THE FIRST FRONT IS KEPT WELL TO THE NORTH...SO TEMPERATURES ARE NOT EXPECTED TO FLUCTUATE MUCH BEHIND THE FRONTAL PASSAGE. THE FIRST FRONT MOVES THROUGH WEDNESDAY NIGHT INTO THURSDAY AND THE NEXT FRONT...ASSOCIATED WITH WESTERLY/SOUTHWEST FLOW ALOFT...MOVES THROUGH FRIDAY NIGHT INTO SATURDAY. TEMPERATURES WITH THE NEXT FRONTAL PASSAGE ALSO ARE NOT EXPECTED TO FLUCTUATE MUCH SINCE HIGHS SHOULD RECOVER AS THE SURFACE HIGH QUICKLY PUSHES EAST BY SATURDAY AFTERNOON. FRONTAL PASSAGES WILL ALSO REMAIN DRY AS THE MAIN FORCING WITH THESE WAVES ALSO REMAINS NORTH OF THE CWA. TOWARDS THE END OF THE PERIOD...THE LARGE SCALE PATTERN SHIFTS EAST WITH THE RIDGE FLATTENING AND MOVING OVER THE CWA THURSDAY THROUGH SATURDAY...WHILE A CLOSED UPPER LOW REMAINS OVER SOUTHERN CALIFORNIA AND SLOWLY MOVES EAST/SOUTHEAST WITH THE SOUTHERN STREAM JET MOVING OVER THE CWA ON SATURDAY. AS PREVIOUSLY MENTIONED...THE EXTENDED PERIOD SHOULD REMAIN DRY...WITH INCREASING MID TO HIGH CLOUDS WITH FRONTAL PASSAGES. TEMPERATURES SHOULD REMAIN SEASONABLE...WITH HIGHS IN THE MID 40S TO LOW 50S AND LOWS IN THE 20S. ONCE EXCEPTION FOR HIGH TEMPERATURES WILL BE WEDNESDAY...AS SURFACE HIGH PRESSURE OVER EASTERN KANSAS EXTENDS INTO THE EASTERN PORTION OF THE CWA...FROM RED WILLOW TO GOVE COUNTY AND EASTWARD...HIGHS COULD ONLY REACH THE UPPER 30S TO LOW 40S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1041 PM MST SAT NOV 23 2013 MODELS DIVERGING ON HOW FAST AND HOW FAR NORTH TO BRING PRECIPITATION AND RICHER LOWER LEVEL MOISTURE. AT THIS TIME IT WOULD SEEM THAT THE NAM AND RUC ARE OVERDOING IT PER LATEST OBSERVATIONS. BOTH MODELS ESPECIALLY THE NAM HAVE BEEN OVERDOING IT HERE RECENTLY. AT THIS TIME IT LOOKS LIKE PRECIPITATION AND LOWER CEILINGS WILL NOT MOVE IN UNTIL NEAR 12Z AT KGLD. WILL HAVE MVFR CEILINGS THERE UNTIL 18Z WITH VERY LIGHT SNOW...ABOVE MVFR...AS WELL. EXPECT VFR CONDITIONS AT KMCK THROUGH THE ENTIRE PERIOD. SOUTH WINDS WILL INCREASE FIRST AT KGLD BETWEEN 06Z AND 12Z AND THEN KMCK BY LATE MORNING. THE STRONGEST GUSTS WILL BE AT KGLD. GUSTS WILL STOP BY 00Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...LOCKHART LONG TERM...ALW AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
157 AM CST Sun Nov 24 2013 ...Updated long term section... .SYNOPSIS... ISSUED AT 1109 AM CST SAT NOV 23 2013 At 12z Saturday a -25c 500mb low was located over southern California. A 300mb +100kt jet streak extended from the based of this upper low northeast into the four corners region. A 700mb to 500mb deformation zone was located from Wyoming, across Colorado, into Oklahoma and a 700mb baroclinic zone extended from southern Colorado into northern Oklahoma. Along and south of this baroclinic zone was also where the better 850mb to 500mb moisture appears to be located based on upper air analysis. A surface to 850mb ridge axis extended from northeast New Mexico into southern Nebraska. An area of high pressure at the surface at 12z was located over the eastern Dakotas. The Dodge City sounding this morning indicated a of drier air was located in the 900mb to 750mb layer, however the Amarillo sounding indicated a deep layer of moisture extending from the surface to the 700mb layer. && .SHORT TERM...(This evening through Sunday) ISSUED AT 218 PM CST SAT NOV 23 2013 Models this morning were all in decent agreement with the southern California upper low slowly moving east across the southwest United States over the next 24 hours. Ahead of this upper trough, isentropic lift and moisture on the I290 and I295 surfaces will improve across southwest Kansas. As this moisture and lift improves the clouds will thicken and lower with even some light snow becoming possible across far southwest Kansas after 03z based on the NAM. The latest HRRR was even a bit more aggressive with the precipitation spreading into southwest Kansas after 00z Sunday, and currently given the precipitation that was already occurring near Amarillo as of 19z will begin to trend toward this slightly quicker solution. This area of light snow will then spread north and east through the overnight period but the better moisture return and isentropic lift still appears to be confined near and south of the Oklahoma border overnight. As a result not expected much in the way of accumulation until the 300mb jet, which was located over Arizona at 12z, begins to approach southwest Kansas after 06z. Possible exception to this will be extreme southwest Kansas near Elkhart. Steady light snow will spread across southwest Kansas after 06z Sunday as synoptic scale lift improves. Given that the moisture and low level isentropic lift will already be in place am currently leaning towards the NAM in snowfall amounts from roughly 06z to 18z Sunday. As a result snow amounts ranging from one to around two inches still appear reasonable south of a Ulysses to Dodge City to Pratt line. The higher 2 inch amounts will be mainly confined near the Oklahoma border on Sunday. Given snow amounts of around 2 inches being possible near the Oklahoma border was considering a winter weather advisory, however at this time given that this is expected to be only a marginal event over a small area have decided to hold off with any type of headlines. Snow accumulations of less than one inch is likely further north given the late timing of the isentropic lift and depth of dry air forecast in the lower levels. .LONG TERM...(Monday through Saturday) ISSUED AT 156 AM CST SUN NOV 24 2013 Upper level ridging will build across the Rockies early this week...but will weaken as it moves across the western plains with predominantly westerly mid level flow across the central and southern plains for much of the remainder of the week. This should keep much of the cold Canadian air to the northeast with temperatures moderating back to seasonal averages across southwestern Kansas. There will be one more arctic high push south Tuesday and Wednesday. Wednesday highs are most uncertain given the strength of this next arctic push...and the latest ECMWF suggests temperatures remaining in the lower 30s much of the day. Wednesday highs may need to be further lowered should this trend continue in the models. Even if Wednesday is colder than currently forecast, it will likely warm right back up Thursday as downslope moment really takes over allowing temperatures to warm well into the 40s, if not a bit warmer. The general zonal nature to the hemispheric pattern does not favor mid-latitude cyclone development through the end of the week, thus precipitation will not be in the forecast. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) ISSUED AT 1211 AM CST SUN NOV 24 2013 CIGS will lower to MVFR/IFR today as warm advection brings plenty of low level moisture northward from the panhandles. Some snow is possible after 12z, especially at KGCK and eventually at KDDC after 15Z. Winds will increase from the south today to 10-14 kts as a surface trough develops in the lee of the Rockies. && .PRELIMINARY POINT TEMPS/POPS... DDC 29 23 38 22 / 60 10 10 10 GCK 30 21 39 22 / 70 10 10 10 EHA 29 23 35 21 / 90 10 10 10 LBL 30 22 34 22 / 90 10 10 10 HYS 31 20 40 22 / 30 10 10 0 P28 28 24 38 23 / 50 20 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY until 4 PM CST /3 PM MST/ this afternoon FOR KSZ061>063-074>078-084>088. && $$ SHORT TERM...Burgert LONG TERM...Umscheid AVIATION...Finch
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1219 AM CST Sun Nov 24 2013 ...Updated for aviation discussion... .SYNOPSIS... ISSUED AT 1109 AM CST SAT NOV 23 2013 At 12z Saturday a -25c 500mb low was located over southern California. A 300mb +100kt jet streak extended from the based of this upper low northeast into the four corners region. A 700mb to 500mb deformation zone was located from Wyoming, across Colorado, into Oklahoma and a 700mb baroclinic zone extended from southern Colorado into northern Oklahoma. Along and south of this baroclinic zone was also where the better 850mb to 500mb moisture appears to be located based on upper air analysis. A surface to 850mb ridge axis extended from northeast New Mexico into southern Nebraska. An area of high pressure at the surface at 12z was located over the eastern Dakotas. The Dodge City sounding this morning indicated a of drier air was located in the 900mb to 750mb layer, however the Amarillo sounding indicated a deep layer of moisture extending from the surface to the 700mb layer. && .SHORT TERM...(This evening through Sunday) ISSUED AT 218 PM CST SAT NOV 23 2013 Models this morning were all in decent agreement with the southern California upper low slowly moving east across the southwest United States over the next 24 hours. Ahead of this upper trough, isentropic lift and moisture on the I290 and I295 surfaces will improve across southwest Kansas. As this moisture and lift improves the clouds will thicken and lower with even some light snow becoming possible across far southwest Kansas after 03z based on the NAM. The latest HRRR was even a bit more aggressive with the precipitation spreading into southwest Kansas after 00z Sunday, and currently given the precipitation that was already occurring near Amarillo as of 19z will begin to trend toward this slightly quicker solution. This area of light snow will then spread north and east through the overnight period but the better moisture return and isentropic lift still appears to be confined near and south of the Oklahoma border overnight. As a result not expected much in the way of accumulation until the 300mb jet, which was located over Arizona at 12z, begins to approach southwest Kansas after 06z. Possible exception to this will be extreme southwest Kansas near Elkhart. Steady light snow will spread across southwest Kansas after 06z Sunday as synoptic scale lift improves. Given that the moisture and low level isentropic lift will already be in place am currently leaning towards the NAM in snowfall amounts from roughly 06z to 18z Sunday. As a result snow amounts ranging from one to around two inches still appear reasonable south of a Ulysses to Dodge City to Pratt line. The higher 2 inch amounts will be mainly confined near the Oklahoma border on Sunday. Given snow amounts of around 2 inches being possible near the Oklahoma border was considering a winter weather advisory, however at this time given that this is expected to be only a marginal event over a small area have decided to hold off with any type of headlines. Snow accumulations of less than one inch is likely further north given the late timing of the isentropic lift and depth of dry air forecast in the lower levels. .LONG TERM...(Sunday night through Saturday) ISSUED AT 150 PM CST SAT NOV 23 2013 Moderation of temperatures is expected in the extended period. Values will start below normal Monday and end up around normal by next Saturday. No precipitation is expected during the period as moisture will remain well southeast of the area. A series of weak front will move across the region next week with the main impact in the form of wind shifts. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) ISSUED AT 1211 AM CST SUN NOV 24 2013 CIGS will lower to MVFR/IFR today as warm advection brings plenty of low level moisture northward from the panhandles. Some snow is possible after 12z, especially at KGCK and eventually at KDDC after 15Z. Winds will increase from the south today to 10-14 kts as a surface trough develops in the lee of the Rockies. && .PRELIMINARY POINT TEMPS/POPS... DDC 29 23 37 23 / 30 10 10 10 GCK 30 21 38 23 / 30 10 10 10 EHA 29 23 35 22 / 60 10 10 10 LBL 30 22 34 23 / 70 10 10 10 HYS 31 20 39 23 / 20 10 10 0 P28 28 24 36 24 / 50 20 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Burgert LONG TERM...Sugden AVIATION...Finch
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1046 PM MST SAT NOV 23 2013 .UPDATE... ISSUED AT 837 PM MST SAT NOV 23 2013 JUST COMPLETED AN UPDATE. CLOUDS HAVE INCREASED THROUGH THE EVENING WITH THE SOUTHERLY WINDS BEGINNING THEIR INCREASE. MANY LOCATIONS IN THE WESTERN AND CENTRAL PORTION OF THE FORECAST AREA MAY HAVE ALREADY REACHED THEIR MINS WITH MUCH HIGHER WINDS EXPECTED IN THE LATER HALF OF THE NIGHT. NAM HAS CAUGHT ON THIS AND USED THIS COMBINED WITH REALITY TO ADJUST THE MINS AND DIURNAL TREND. IN REGARDS TO THE WINDS INCREASED THEM EARLIER...BEGINNING BETWEEN 06Z AND 12Z. AREA SOUNDINGS CONFIRMING WHAT MODEL DATA IS SHOWING IN REGARDS TO PRECIPITATION CHANCES. STILL A LOT OF DRY AIR IN THE LOW LEVELS AND WILL TAKE A WHILE TO SATURATE. THAT LOOKS TO HAPPEN BETWEEN 06Z AND 12Z WITH HIGHER POPS LATER TONIGHT INTO TOMORROW. SO REMOVED PRECIPITATION CHANCES AND STARTED THE INCREASE AFTER 06Z A LITTLE SLOWER THAN PREVIOUSLY DEPICTED. ALSO RAMPED UP THE SKY COVER AS WELL PER SATELLITE AND LATEST GUIDANCE. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 105 PM MST SAT NOV 23 2013 19Z WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LARGE CLOSED LOW CIRCULATION OVER THE EXTREME SOUTHWESTERN CONUS WITH SHORTWAVE RIDGING IN PLACE ACROSS THE CWA. AT THE SFC...1047MB SFC RIDGE AXIS WAS NOSING INTO EASTERN KANSAS WITH CWA ON WESTERN PERIPHERY OF THIS FEATURE. MAIN CONCERN FOR THE SHORT TERM PERIOD WILL BE PRECIPITATION CHANCES OVERNIGHT TONIGHT INTO TOMORROW. WHILE STORM SYSTEM IN THE SOUTH WILL GENERALLY REMAIN WELL TO THE SOUTH OF THE CWA...PERIOD OF ASCENT/MOISTURE ADVECTION EXPECTED TO DEVELOP TONIGHT WHICH MAY BRING A PERIOD OF LIGHT SNOW TO AREA BTWN 09 AND 18Z. LOOKING AT VARIOUS MODEL ISENTROPIC/STABILITY FIELDS...APPEARS THAT OVERALL FORCING PRETTY WEAK WITH MAIN DIFFERENCE BETWEEN DRY/WET MODELS ARE THE DEGREE OF POTENTIAL INSTABILITY PRESENT. NOT REAL CONFIDENT IN MORE UNSTABLE SOLUTIONS SO FOR THE TIME BEING PLAN ON TEMPERING POPS IN THE 20-40 PERCENT RANGE AND SNOW AMOUNTS. COULD POSSIBLY SEE A FEW SPOTS OF 2-3 INCHES IN THE SOUTHWEST...BUT THINK MOST LIKELY SCENARIO WILL BE AROUND AN INCH SOUTH OF INTERSTATE. OTHERWISE...WINDS WILL SHIFT TO THE SOUTH AND INCREASE LATE TONIGHT THROUGH SUNDAY INCREASING TO 20 TO 30 MPH DURING THE DAY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 227 PM MST SAT NOV 23 2013 THE LARGE UPPER LOW OVER THE SOUTHWEST U.S. WILL LIFT NORTHEAST TO THE CO-NM BORDER SUNDAY NIGHT BEFORE HEADING BACK SOUTHEAST ACROSS THE GULF BY TUESDAY. WEAK ASCENT AHEAD OF THE UPPER LOW AND ITS CLOSE PROXIMITY WILL RESULT IN A BRIEF PERIOD OF LIGHT SNOW/FLURRIES AS SHOWN ON THE SREF. ANY SNOW AMOUNTS WILL BE LIGHT AND CONFINED TO THE SOUTHERN HALF OF THE AREA. THE REST OF THE EXTENDED PERIOD WILL BE UNDER THE INFLUENCE OF AN UPPER RIDGE TUESDAY-WEDNESDAY WHICH WILL ULTIMATELY FLATTEN OUT DURING THE WEEK. NO PRECIPITATION IS EXPECTED FOR THE REMAINDER OF THE WEEK AS A RESULT. AT THE SURFACE...A WEAK COLD FRONT WILL PUSH THROUGH MONDAY FOLLOWED BY A REINFORCING CANADIAN AIR MASS WHICH DOMINATES TUESDAY-WEDNESDAY. THIS WILL KEEP TEMPERATURES BELOW NORMAL THROUGH AT LEAST MID-WEEK WITH HIGHS IN THE 30S MONDAY WARMING TO THE 40S BY WEDNESDAY. THE LAST HALF OF THE WEEK WILL SEE A RETURN TO NORMAL TEMPERATURES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1041 PM MST SAT NOV 23 2013 MODELS DIVERGING ON HOW FAST AND HOW FAR NORTH TO BRING PRECIPITATION AND RICHER LOWER LEVEL MOISTURE. AT THIS TIME IT WOULD SEEM THAT THE NAM AND RUC ARE OVERDOING IT PER LATEST OBSERVATIONS. BOTH MODELS ESPECIALLY THE NAM HAVE BEEN OVERDOING IT HERE RECENTLY. AT THIS TIME IT LOOKS LIKE PRECIPITATION AND LOWER CEILINGS WILL NOT MOVE IN UNTIL NEAR 12Z AT KGLD. WILL HAVE MVFR CEILINGS THERE UNTIL 18Z WITH VERY LIGHT SNOW...ABOVE MVFR...AS WELL. EXPECT VFR CONDITIONS AT KMCK THROUGH THE ENTIRE PERIOD. SOUTH WINDS WILL INCREASE FIRST AT KGLD BETWEEN 06Z AND 12Z AND THEN KMCK BY LATE MORNING. THE STRONGEST GUSTS WILL BE AT KGLD. GUSTS WILL STOP BY 00Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...JRM LONG TERM...DLF AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS PADUCAH KY
742 PM CST Mon Nov 25 2013 .UPDATE... ISSUED AT 742 PM CST MON NOV 25 2013 A slightly more modest change in precipitation chances and other sensible weather elements (weather, temperature, dewpoint, wind, etc) for tonight and Tuesday morning, mainly over West Kentucky. The current wave of precipitation and sub-synoptic lift is moving out of the area, creating a small droplet size area of rain/mist, as well as snow over the eastern 1/3 of the WFO PAH County warning area. Regional radar mosaic still showing 0 to 15/20 dBZ returns over Central Arkansas, Southeast Misouri, Southeast Illinois, and into Northwest Kentucky and Southwest Indiana shortly after 01z (7 pm CST) this evening. This is coincident with the southern edge of a differential deformation zone/moisture gradient on the 7.0 micron (sensitive near 700 mb) and 7.4 micron (sensitive near 850 mb) GOES Sounder Water Vapor channels. On the 11-3.9 micron GOES IR difference channel, the aforementioned radar echoes are centered within the mean plume of ice clouds, serving as seeder-feeder source region. The GEM (Canadian), SREF (Short Range Ensemble Forecast), deterministic 18z GFS numerical guidance are similar to the high resolution 3km HRRR model guidance for this evening and overnight. We should see a resurgence of PoPs/Weather from the southwest into the Missouri Bootheel and Southwest Kentucky after midnight (06z). A sharp northern PoP/Weather gradient should develop over West Kentucky after midnight, slowly working east-northeast through 8 am CST Tuesday, then continue to shift east during the day on Tuesday. By 9 am CST Tuesday, most areas should remain above freezing over the entire WFO PAH CWA, eliminating any travel concern. For now, the most concentrated area for travel concerns between 11 pm Monday and 8 am Tuesday will be from Paducah KY (KPAH) and Owensboro KY (KOWB) southward 25 to 30 miles through 5 am CST, working slightly more southward another 10 to 15 miles between 5 am - 8 am CST. The combination and duration of temperatures slightly below freezing, PoPs above 40%, and differential lift may lead some slight glazing on elevated surface and some roadways. For now, will issue a longer term Special Weather Statement to address this area of travel concern, as well as post a Weather Story graphic on the NWS Paducah web page and social media outlets. May also highlight in the Hazardous Weather Outlook as well. Given the marginal nature of the precipitation amounts (between 0.04" - 0.07") it will be a judgement call whether an advisory will be needed overnight, since critical temperatures will focused in areas where total precipitation will be less than 0.05" between 11 pm and 8 am CST. Given the effectiveness of de-icing agents (salt, etc...) most roads should remain in good shape. The only areas of concern will be any untreated roadways. && .SHORT TERM...(This Evening through Tuesday night) ISSUED AT 239 PM CST MON NOV 25 2013 Models were obviously too slow with precip onset with this initial wave. Not an uncommon error. Light sleet, light rain light snow mix across the area. Most notable precip has been over west KY and southeast MO, near the TN state line over to the MO bootheel region. We will maintain our SPS (Special Weather Statement) approach vs. an advisory. A few slick spots certainly possible though not getting really any reports of that. Temperatures per KY mesonet into SEMO at or above freezing even where precip has occurred. Site near Hickman is down to 32F. Overall, still not a big deal event. This lead wave will push the afternoon activity on to the east. The question then becomes, how much more will we see overnight into early Tuesday. Will maintain slight better chances overnight south and east and taper off low chance PoPs NW overnight, and continue with our SE 1/3 of the area PoPs Tuesday as the southern and northern stream systems interact and draw moisture into this area. Should be dry over the remainder of the region Tuesday. A minimal mix precip type possible tonight into early Tuesday a.m. Then precip should transition to mainly light rain. Tuesday night will be dry and colder as arctic high pressure builds south into the area. .LONG TERM...(Wednesday through Monday) ISSUED AT 239 PM CST MON NOV 25 2013 With precipitation having moved east of the PAH forecast area, Wednesday will see clearing skies as chilly and breezy conditions persist through the day. With highs only in the lower 30s, wind chill readings in the morning will start out in the single digits to around 10 degrees, only improving to the lower 20s by afternoon. The coldest period of the extended will continue into Wednesday night, with lows in the middle to upper teens. Northwest winds at 5 to 10 mph in the evening will decrease and gradually turn back to the southwest by daybreak. High pressure over the central plains Wednesday will slide east of the PAH fa by Thursday morning, thus the winds becoming southwest. Southwest flow will lead to a gradual warm up through the weekend, though readings will remain below normal. High temperatures on Thanksgiving will only reach the middle to upper 30s, moderating to the upper 40s to around 50 degrees Saturday and Sunday. Lows Saturday night are expected to stay above freezing, which will be the first night with above freezing temperatures since last weekend. ECMWF brings a surface low into the Great Lakes region by 12z Sunday, dragging a cold front into the Mississippi River valley. GFS is about 12 hours slower than the ECMWF. ECMWF spreads rain across much of the PAH fa Saturday night, while GFS holds off until late Sunday into Sunday night. Went with a compromise, keeping Saturday night dry then including slight to low chance pops for mainly southern Illinois and southeast Missouri on Sunday. Went with chance pops across the entire area Sunday night into Monday. Fortunately, temperatures look to be warm enough through the event to keep precip all liquid. && .AVIATION... ISSUED AT 602 PM CST MON NOV 25 2013 A light wintry mix of precipitation will continue through the evening over much of the area. Added a TEMPO group for MVFR ceilings with light snow at KPAH and KOWB where a few periods of pure snow will be possible. The latest guidance hints at some seeder/feeder potential straddling 12Z at KPAH, and throughout Tuesday morning at KOWB. It looks like there may be enough warming aloft to create a rain/snow mix with some potential for FZRA. Will stick with the -RASN with MVFR ceilings at KPAH and KOWB for now. Would not be surprised to see the wintry mix continue at least intermittently through the night at KPAH and KOWB. Light and variable winds will be the rule until Tuesday morning, when light north winds are expected to develop. As surface high pressure builds eastward across the area in the afternoon, gusts up to 20kts will be possible. The gustiness will mostly be confined to KCGI before Tuesday evening. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...Smith AVIATION...DRS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
925 PM EST MON NOV 25 2013 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL PUSH OFFSHORE OVERNIGHT. LOW PRESSURE WILL MOVE NORTHEAST OUT OF THE GULF OF MEXICO AND UP THE EAST COAST ON TUESDAY AND WILL REACH THE VICINITY OF LONG ISLAND BY WEDNESDAY MORNING. LOW PRESSURE WILL CONTINUE NORTHEAST THROUGH THE REGION ON WEDNESDAY AND WILL SHIFT INTO THE MARITIMES WEDNESDAY NIGHT. A STRONG NORTHWEST FLOW WILL SET UP BEHIND THE STORM LATE WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THURSDAY NIGHT THROUGH FRIDAY. HIGH PRESSURE WILL HOLD OVER THE REGION ON SATURDAY AND WILL SHIFT OFFSHORE ON SUNDAY. && .NEAR TERM /THROUGH TUESDAY/... UPDATE...HAVE DELAYED THE TIMING OF PCPN INTO THE AREA...AS DEW POINTS REMAIN IN THE SINGLE DIGITS. PLENTY OF VIRGA OUT THERE RIGHT NOW...WITH LITTLE IN THE WAY OF SN IN METAR OBS. HI-RES GUIDANCE LIKE THE RAP AND HRRR INDICATE A NARROW BAND OF FRONTOGENESIS TO MOVE INTO NH AND WRN ME NEAR DAWN. COULD SEE A STRIPE OF NEAR A HALF INCH ACCUM FROM ROUGHLY KLEB TO KIZG IF THIS COMES TO FRUITION. THIS ACTUALLY CORRESPONDS FAIRLY WELL TO UPSTREAM SATELLITE OBS...SO SEE NO REASON WHY THE MODELS MAY BE IN ERROR. THE MAIN QUESTION WILL BE WHETHER THE COLUMN CAN SATURATE ENOUGH FOR AN ACCUMULATING SNFL. PREVIOUS DISCUSSION...WEAK OVER-RUNNING WILL SHIFT IN FROM THE WEST OVERNIGHT AS LOW PRESSURE MEANDERS OVER SOUTHWEST QUEBEC. WILL SEE INCREASING CLOUDS DURING THE EVENING HOURS WITH A CHANCE OF SNOW SHOWERS EDGING INTO NORTHERN ZONES. HAVE GENERALLY GONE WITH LOW CHANCE POPS FROM THE GFS AS LIFT RATHER WEAK. COULD SEE A FEW STRAY SNOW SHOWERS DRIFTING INTO SOUTHERN ZONES AROUND DAYBREAK BUT THESE WILL BE LIGHT AND SPOTTY WITH LITTLE OR NO IMPACT. WILL BE ANOTHER COLD NIGHT DESPITE THE CLOUDS WITH LOWER TO MID TEENS IN THE NORTH AND UPPER TEENS TO MID 20S IN THE SOUTH. && .SHORT TERM /TUESDAY NIGHT/... UPDATE...AFTER EXAMINING THE LATEST AVAILABLE DATE HAVE MADE A FEW TWEAKS TO THE TUE FORECAST. ANY MIXED PCPN SHOULD BE LIMITED TO NRN VALLEYS AND HIGH TERRAIN. ALONG THE COAST AND COASTAL PLAIN ANY SNFL SHOULD QUICKLY CHANGE TO RA AS WAA INCREASES. DEEPER COLD AIR IN THE MTNS SHOULD SUPPORT 1-3 INCHES SNFL BEFORE A FLIP TO A BRIEF MIX THEN RA. PREVIOUS DISCUSSION...WEAK OVER-RUNNING WILL SHIFT EAST OF THE REGION ON TUESDAY. MAY CATCH A FEW SUNNY BREAKS BEFORE CLOUDS INCREASE FROM THE SOUTH IN THE AFTERNOON. APPEARS ANY PRECIP ASSOCIATED WITH LOW PRESSURE MOVING UP THE COAST WILL HOLD OFF UNTIL AFTER SUNSET TUESDAY EVENING BUT HAVE INCLUDED SOME LOW CHANCE POPS FOR SOUTHERN NEW HAMPSHIRE FOR THE EARLY EVENING. WILL SEE HIGHS MUCH CLOSER TO NORMAL ON TUESDAY WITH MOST OF THE REGION RANGING THROUGH THE 30S. EXPECT MIXED PRECIPITATION TO BREAK OUT ACROSS SOUTHERN ZONES DURING THE EVENING HOURS WITH NORTHERN ZONES SEEING SNOW AT THE ONSET. WARMER AIR WILL QUICKLY FLOOD IN FROM THE SOUTH TUESDAY EVENING SO ANY MIXED PRECIP IN SOUTHERN INTERIOR SECTIONS WILL LIKELY GO OVER TO RAIN BY MIDNIGHT OR SHORTLY AFTER...BECOMING HEAVY AT TIMES AFTER MIDNIGHT. IN THE FOOTHILLS AND MOUNTAINS WILL SEE SNOW GOING OVER TO SLEET AND FREEZING RAIN AFTER MIDNIGHT WITH SOME ICE ACCUMULATIONS LIKELY. AT THIS POINT IN TIME WINTER WEATHER ADVISORIES SHOULD COVER THE SITUATION IN CENTRAL AND NORTHERN AREAS. EXPECT SNOW ACCUMULATIONS OF 3 TO 5 INCHES BEFORE THE CHANGE TO SLEET AND FREEZING RAIN IN FAR NORTHERN ZONES. ICE ACCUMULATIONS ON TOP OF THE SNOW WILL BE IN THE .1 TO.3 INCH RANGE. EXPECT TEMPS TO RISE THROUGH THE NIGHT AND HAVE GONE WITH A NON- DIURNAL TEMP CURVE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... UPDATE...STRONG PRES FALLS TO THE S WILL SUPPORT A NLY COMPONENT OF THE WIND. THIS SHOULD HELP COOLER AIR STAY LOCKED IN THE INTERIOR LONGER. MAIN EFFECT WAS TO BRING HIGH TEMPS DOWN IN THE INTERIOR...AS EFFECT ON SENSIBLE WX WILL JUST BE A COLDER RNFL. VERY STRONG LLJ IN PLACE...HOWEVER DEGREE OF WAA ALOFT WILL CREATE A STOUT TEMP INVERSION. WILL BE TOUGH TO FULLY MIX DOWN STRONGEST WINDS...ALTHOUGH TURBULENT MIXING SHOULD STILL BE ENOUGH TO SEE 40-45 MPH GUSTS ALONG THE COAST. THE INTERIOR WILL HAVE MORE TROUBLE MIXING DOWN THE WINDS...AS LLVL COOLER AIR WILL BE TOUGHER TO FLUSH OUT. NWP CONTINUES TO ADVERTISE A HEAVY RNFL EVENT WED INTO THU. WITH STRONG SELY UPSLOPE COMPONENT TO THE WIND...MAX RNFL TOTALS MAY PUSH 5 INCHES IN SPOTS. WILL MENTION THIS IN THE HWO...ALONG WITH WINDS...AS THESE SEEM TO BE THE MAIN IMPACTS ATTM. AS RAPIDLY DEEPENING LOW PRES PULLS THRU AND N OF THE AREA...PRES WILL SHARPLY RISE BEHIND IT. THIS RISE/FALL COUPLET IS FORECAST TO MORE OR LESS TRACK RIGHT OVER THE HEART OF THE CWFA. THIS WILL SUPPORT ANOTHER ROUND OF STRONG WIND GUSTS...THIS TIME FROM A WLY DIRECTION...FOR THE ENTIRE REGION. PREVIOUS DISCUSSION...MODELS SHOWING A POTENTIAL HEAVY RAIN EVENT FOR WEDNESDAY WITH 2-3 INCH QPF STORM TOTAL POSSIBLE OVER MUCH OF THE FCST AREA. MODELS ALSO SHOWING MAX AMOUNTS MAY APPROACH 3.5 INCHES. IT HAS BEEN QUITE DRY OCT THRU NOV BUT STILL THIS MUCH QPF WILL CREATE SHARP RISES ON STREAMS AND SMALLER RIVERS. ANY MIXED PRCP PRIOR TO WEDNESDAY SHOULD QUICKLY TRANSITION TO RAIN EARLY WEDNESDAY. WINDS PICK UP...MAINLY ALONG THE COAST AND HIGHER/MORE EXPOSED TERRAIN WITH STRONG LOW LVL SOUTHERLY FLOW SETTING UP AHEAD OF THE DEEPENING SFC LOW. THE LOW AND A TRAILING COLD FRONT MOVE THRU WEDNESDAY EVENING WITH RAIN AND ANY STRONG SOUTHERLY WINDS COMING TO AN END. BEHIND THE SYSTEM MUCH COLDER AIR MOVES IN QUICKLY ON INCREASINGLY STRONG AND GUSTY NW WINDS. PRCP LIKELY TO FALL ACROSS N/MT ZONES WITH ANY MIXED QUICKLY CHANGING TO SHSN...WITH ACCUMULATIONS LIKELY AS AN UPPER LEVEL SHORT WAVE MOVES THRU AND UPSLOPE NW FLOW TAKES OVER. SOME -SHSN WILL FIND THEIR WAY TO THE COAST UNDER THE VIGOROUS UPR LVL SYSTEM BUT DOWNSLOPE FLOW WILL HELP OFFSET INTENSITY. THE UPR LVL TROF MOVES TO THE E THURSDAY MORNING BRINGING AN END TO MOST -SHSN ACTIVITY THOUGH THE CONTINUED COLD UPSLOPE NW FLOW WILL KEEP SOME -SHSN GOING ACROSS THE N/MT ZONES. A VERY COLD BLUSTERY DAY ON THURSDAY FOR THE FCST AREA AS STRONG SFC PRES GRADIENT FROM THE STRONG LOW PRES SYSTEM MOVING THRU THE MARITIMES SETS UP THE NW FLOW WHICH LINES UP SFC AND ALOFT...THOUGH THE FLOW BECOMES MORE WESTERLY AT 700 MB AND HIGHER. HIGH PRES BUILDS IN FROM THE WEST THURSDAY NGT THRU FRIDAY NGT AS VERY COLD AIR DOMINATES. THE STRONG GUSTY NW FLOW SLOWLY LETS UP DURING THE PERIOD OF TIME. THE HIGH SETTLES OVER THE REGION SATURDAY WITH FAIR BUT COOL WX. THE HIGH MOVES TO THE E ON SUNDAY AS WARMER AIR BEGINS TO MOVE IN ON SW FLOW ALOFT. MOSTLY LIKELY TO STAY DRY AS THE HIGH STILL HAS INFLUENCE OVER OUR WX. AN UPR LVL SYSTEM AND INCREASING WARM AIR ADVECTION AND MOISTURE ADVECTION FROM THE SW MAY BRING SOME LGT PRCP SUNDAY NGT AND MONDAY. USED A BLEND OF MODELS AND MOS GUIDANCE ALONG WITH HPC QPF FOR PERIODS 4 AND 5...THEN USED A SUPER BLEND OF VARIOUS MODELS AND MOS GUIDANCE ...ALONG WITH BIAS CORRECTED GUIDANCE AND THE PREVIOUS FORECAST FOR DAYS 4 THRU 8...EXCEPT INCREASED WINDS ON THURSDAY OVER THE SUPER BLEND DUE TO STRONG PRES GRADIENT LINING UP SFC TO FLOW ALOFT AND STRONG COLD AIR ADVECTION TO SUPPORT VERY STRONG GUSTY NW WINDS. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... SHORT TERM...VFR TONIGHT THROUGH TUESDAY. IFR/LIFR CEILINGS/VSBY DEVELOPING TUESDAY NIGHT. LONG TERM /WEDNESDAY THROUGH SATURDAY/...IFR/LIFR IN HEAVY RAIN WEDNESDAY. GUSTY SOUTHERLY WINDS...WITH LLWS POSSIBLE IN THOSE AREAS THAT DON`T SEE THE STRONG LOW LVL WIND FIELD MIX DOWN TO THE SFC. SHSN WEDNESDAY NGT INTO THURSDAY...MOSTLY AFFECTING THE N/MT AREAS WITH MVFR/IFR POSSIBLE. STRONG NW FLOW DEVELOPING WEDNESDAY NGT AND BECOMING STRONGEST ON THURSDAY...BEFORE EASING UP FRIDAY. && .MARINE... SHORT TERM...DROPPING SCA`S FOR WESTERN AND CENTRAL WATERS...INCLUDING CASCO BAY. CONTINUING SCA`S FOR WINDS AND SEAS IN FAR EASTERN WATERS AND PENOBSCOT BAY TIL 00Z. LONG TERM /WEDNESDAY THROUGH SATURDAY/...STRONG SOUTHERLY FLOW ON WEDNESDAY. MODELS SHOW A LOW LVL JET UPWARDS OF 90 KT AT 2K FT AND SFC WINDS UP TO 40 KT. WINDS SHOULD MIX DOWN TO CREATE STORM FORCE GUSTS. WILL ISSUE A MARINE STORM WATCH FOR WEDNESDAY. WILL ALSO INCREASE WIND AND WAVE HEIGHT FORECASTS OVER GUIDANCE. WINDS SHIFT TO NW AS THE SYSTEM GOES BY WEDNESDAY EVE. GUSTY NW FLOW INCREASES WEDNESDAY NGT AND BECOMES STRONGEST ON THURSDAY WHEN GALES MAY BE NEEDED. NW FLOW SLOWLY EASES UP FRIDAY THRU SATURDAY AS HIGH PRES BUILDS IN FROM THE W. SEAS WILL CONT VERY CHOPPY BUT THE TREND WILL BE FOR THEM TO SLOWLY SUBSIDE STARTING WEDNESDAY NGT...BUT MAY NOT DROP BELOW SCA LEVELS UNTIL FRIDAY MORNING. && .TIDES/COASTAL FLOODING... WEDNESDAY...STRONG ONSHORE FLOW WILL CREATE A STORM SURGE THAT COULD REACH 2 OR EVEN 3 FT. TIDE AT PWM PREDICTED TO BE AROUND 8 1/2 FT SO SHOULD STAY BELOW THE 12 FT TIDAL FLOOD STAGE AT PORTLAND. HOWEVER... THE STRONG ONSHORE FLOW WILL GENERATE VERY SIGNIFICANT WAVE HEIGHTS WHICH MAY LEAD TO SPLASHOVER/BEACH EROSION ALONG THE COAST. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...STORM WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR ANZ150>154. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS GRAY ME
1234 AM EST SUN NOV 24 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION TONIGHT WITH A STRONG NORTHWEST FLOW SETTING UP BEHIND IT. HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND SUNDAY THROUGH MONDAY. A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST MONDAY NIGHT AND TUESDAY AND WILL CROSS THE REGION TUESDAY NIGHT. LOW PRESSURE WILL MOVE UP THE EAST COAST ON WEDNESDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THURSDAY THROUGH FRIDAY. HIGH PRESSURE WILL CREST OVER THE REGION ON FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1225 AM...A MINOR ESTF TO ADJUST 1ST PERIOD GRIDS TO REFLECT MESONET. WINDS HAVE COME UP QUICKER ON THE WATERS AND THE GALE WILL BE STARTED AS OF 05Z. PREV DISC... UPDATE...HAVE UPDATED POP ONCE AGAIN TO TRACK THE LATEST BATCH OF SN SQUALLS CROSSING THE WHITE MTNS ATTM. THE 24/00Z HRRR ACTUALLY HAS A VERY GOOD HANDLE ON THE CURRENT SPEED AND FAIR ESTIMATE ON LOCATION OF THE SQUALL. SO HAVE BLENDED THE PREVIOUS FORECAST WITH THIS LATEST GUIDANCE TO BRING THE OFFICIAL FORECAST IN THAT DIRECTION FOR THE NEXT SEVERAL HOURS. WILL CONTINUE HEAVY SNFL WORDING WITH THIS PCPN...AS EVEN THOUGH THE DURATION WILL BE SHORT LIVED...THE INTENSITY WILL BE ENOUGH TO CAUSE TROUBLE. PREVIOUS DISCUSSION...ARCTIC COLD FNT MAKING QUICK PROGRESS TOWARDS THE CWFA ATTM. SHSN AND SQUALLS WILL BECOME MORE NUMEROUS AS IT APPROACHES THIS EVENING. STRONG CAA IS DESTABILIZING THE LLVLS...ALLOWING SHSN TO BECOME QUITE INTENSE AT TIMES. LOOKING AT UPSTREAM OBS AND WEBCAMS...VSBYS WILL DROP TO 1/4SM OR LESS AT TIMES. HAVE ADDED HEAVY SN WORDING TO SRN NH AND ADJACENT SWRN ME FOR THE NEXT SEVERAL HOURS AS SQUALLS TRACK OVER THESE AREAS. ADDITIONALLY...ABOVE FREEZING TEMPS TODAY WILL MEAN ROAD TEMPS WILL BE WARM ENOUGH TO MELT SNFL INITIALLY. HOWEVER...RAPIDLY FALLING TEMPS WILL MEAN THIS WILL REFREEZE...CREATING VERY ICY ROADWAYS. SEEING AS THESE SHSN WILL BE CROSSING INTERSTATES 89...93...AND 95 THIS IS A CONCERN. USED A BLEND OF THE LATEST RAP AND HRRR TO TREND POP OVER THE NEXT FEW HOURS. OTHERWISE FORECAST LOOKS ON TRACK AS BITTER COLD HEADS TOWARDS THE REGION. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM MONDAY/... FOR SUNDAY WE HAVE ISSUED A WIND ADVISORY. LOOKING AT BUFKIT DATA SHOWS WINDS TO 40 TO 50 KTS DOWN TO 2K FEET WITH STEEP LAPSE RATES. THE STRONGEST WINDS ARE LIKELY TO BE IN THE 18Z TO 03Z TIME FRAME. WINDS GUSTS TO 45 TO 50 MPH ARE CERTAINLY POSSIBLE. EXPECT THERE WILL BE POWER OUTAGES AS THE DAY GOES ON. TEMPERATURES WILL RISE ABOUT 5 TO 10 DEGREES TOMORROW WHICH WILL PUT HIGH TEMPS IN THE 20S MOST EVERYWHERE WITH SOME UPPER TEENS IN THE MOUNTAINS. THIS IS A GOOD 20 DEGREES BELOW NORMAL. SNOW SHOWERS WILL BE LIKELY IN THE MOUNTAINS WITH 1 TO 3 INCHES POSSIBLE. FOR SUNDAY NIGHT WINDS WILL ABATE SOMEWHAT AFTER MIDNIGHT BUT TEMPS WILL PLUNGE. EXPECT AROUND ZERO IN THE MOUNTAINS AND NEAR 10 AT THE COAST. RECORD LOW FOR PORTLAND MONDAY IS 9 DEGREES. WILL BE CLOSE TO THIS. && .LONG TERM /MONDAY THROUGH SATURDAY/... RIDGE OF HIGH PRESSURE WILL CREST OVER THE REGION MONDAY BEFORE SHIFTING OFFSHORE. EXPECT A SUNNY START TO THE DAY BEFORE HIGH CLOUDS SPILL IN FROM THE WEST IN THE AFTERNOON. WILL BE ANOTHER COLD ONE WITH HIGHS ONLY REACHING THE UPPER TEENS TO LOWER 20S NORTH AND MID 20S TO NEAR 30 SOUTH. AREA OF WEAK OVER-RUNNING AHEAD LOW PRESSURE MOVING THROUGH SOUTHERN CANADA WILL PUSH IN FROM THE WEST MONDAY NIGHT BRINGING SOME LIGHT SNOW TO THE REGION. BEST CHANCES OF PRECIP WILL BE IN NORTHERN ZONES WHERE AN INCH OR TWO OF ACCUMULATION WILL BE POSSIBLE. ELSEWHERE JUST LOOKING FOR A LIGHT DUSTING. LOOKING FOR LOWS IN THE MID TEENS TO LOWER 20S. CLOUDS AND LINGERING FLURRIES WILL GIVE WAY TO PARTLY SUNNY SKIES ON TUESDAY. COLD FRONT APPROACHING FROM THE WEST MAY BRING SNOW SHOWERS TO THE MOUNTAINS BY LATE IN THE DAY. SHOULD SEE A MUCH WARMER DAY WITH TEMPS RANGING THROUGH THE 30S. COLD FRONT WILL SWING THROUGH THE REGION TUESDAY NIGHT BRINGING A CHANCE OF SNOW SHOWERS IN THE NORTH AND VARIABLE CLOUDS ACROSS SOUTHERN AREAS. OVERNIGHT LOWS WILL RANGE THROUGH THE 20S. MODELS STILL FAR APART ON WEDNESDAY WITH THE ECMWF BRINGING LOW PRESSURE UP THE EAST COAST AND GFS TAKING THE SAME SYSTEM WELL OFFSHORE. AT THIS POINT SUPER BLEND GIVING LIKELY POPS WITH A MIX OF RAIN AND SNOW IN THE SOUTH AND SNOW IN THE FOOTHILLS AND NORTH. SO POTENTIAL IS STILL THERE FOR SIGNIFICANT SNOW IN THE NORTH AND A MESSY MIX IN THE SOUTH. HIGH TEMPS WILL RANGE THOUGH THE 30S TO NEAR 40. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THURSDAY THROUGH FRIDAY. EXPECT TEMPS ONCE AGAIN BELOW NORMAL THURSDAY AS COLD CANADIAN AIR FLOODS IN ON A STRONG NORTHERLY WINDS. WILL SEE TEMPS MODERATE SOMEWHAT ON FRIDAY AS HIGH PRESSURE CRESTS OVER THE REGION. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... SHORT TERM...EXPECT MOSTLY VFR. BRIEF MVFR/IFR PSBL LATE TONIGHT IN SNOW SHOWERS. HIE WILL SEE MOSTLY MVFR. LONG TERM...VFR MONDAY THROUGH TUESDAY. IFR/LIFR CEILINGS AND VSBY DEVELOPING ON WEDNESDAY. VFR THURSDAY. && .MARINE... SHORT TERM...GALE WARNING HAS BEEN ISSUED. LONG TERM...GALES POSSIBLE ON WEDNESDAY. && .CLIMATE... SIGNIFICANT OUTBREAK OF EARLY SEASON COLD AIR WILL CHALLENGE SOME LOCAL RECORDS OVER THE NEXT COUPLE OF DAYS. AT KPWM THE RECORD COLD MAXIMUM TEMP FOR 11/24 IS 28 SET IN 1989. THE TEMP AROUND MIDNIGHT TONIGHT WILL LIKELY BE THE WARMEST KPWM GETS ALL DAY...AND WILL BE VERY CLOSE TO 28 DEG. ON 11/25 KPWM HAS A RECORD COLD MAXIMUM TEMP OF 29 SET IN 1993. THE CURRENT FORECAST IS FOR A HIGH TEMP AROUND 30. FOR LOW TEMP ON 11/25...KPWM SET A RECORD IN 2000 OF 9 DEG. THE CURRENT FORECAST IS FOR 11/25 IS A LOW TEMP AROUND 10 DEG. A LITTLE COOLER BUT SIMILARLY FOR KCON...THE RECORD COLD MAXIMUM TEMP FOR 11/24 IS 24 SET IN 1921. WHILE IN 1938 THE RECORD COLD MAXIMUM TEMP FOR 11/25 WAS SET AT 21. THE RECORD LOW TEMP FOR 11/25 IS 5 DEG SET IN 1956 AND 2000. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WIND ADVISORY UNTIL 1 AM EST MONDAY FOR MEZ007>009-012>014- 018>028. NH...WIND ADVISORY UNTIL 1 AM EST MONDAY FOR NHZ001>010-013-014. MARINE...GALE WARNING UNTIL 7 AM EST MONDAY FOR ANZ150>154. && $$ ES
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1211 PM EST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 526 AM EST SUN NOV 24 2013 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES WITH GRADUALLY RISING HEIGHTS AS THE TROUGH OVER THE NE CONUS SLIDES TO THE EAST AND MID LEVEL RIDGING BUILDS TOWARD THE AREA FROM SOUTH CENTRAL CANADA. AT THE SFC...A RIDGE WAS BUILDING FROM NW WI AND WRN LAKE SUPERIOR INTO FAR W UPPER MI WHILE LAKE INDUCED TROUGHING PREVAILED THROUGH ERN LAKE SUPERIOR. SATELLITE AND RADAR INDICATED NW-SE ALIGNED WIND PARALLEL LES BANDS HAD SHIFTED INTO LOCATIONS E OF MARQUETTE COUNTY. THE BANDS HAD ALSO BECOME MORE CELLULAR WITH GRADUALLY DECREASING INTENSITY OVERNIGHT. SFC OBS STILL INDICATED INTO W UPPER MI WITH CMX SHOWING VSBY IN THE 1-3SM RANGE. HOWEVER...WEBCAMS FROM HOUGHTON AND CALUMET SHOWED LITTLE SNOW OR VSBY REDUCTION. THIS MORNING... DESPITE 850 MB TEMPS AROUND -20C...INVERSION HEIGHTS DROPPING BELOW 5K FT AND VERY DRY AIR UPSTREAM WILL CONTINUE TO LIMIT LES INTENSITY...ESPECIALLY OVER THE WEST. DIMINISHING WINDS WITH AN INCREASED LAND BREEZE INFLUENCE AND A BACKING TREND WITH THE APPROACHING RIDGE WILL RESULT IN A PERIOD OF ENHANCED CONVERGENCE FROM ERN LAKE SUPERIOR INTO UPPER MI BETWEEN MUNISING AND NEWBERRY WHERE ADDITIONAL SNOW AMOUNTS IN THE 1 TO 3 INCH RANGE ARE EXPECTED THROUGH THE MORNING. THE BACKING WINDS SHOULD PUSH THE REMAINING LES OFFSHORE IN THE AFTERNOON. THIS AFTERNOON AND TONIGHT... DEVELOPING WAA WITH STRONG 280K-295K PRES ADV BUT ONLY WEAK TO MODERATE NET LIFT AHEAD OF A SHRTWV AND SFC LOW MOVING INTO CNTRL MANITOBA MAY LEAD TO AN AREA OF LIGHT SNOW STREAKING SE INTO THE NORTH AND EAST PORTIONS OF UPPER MI LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH THE DRY LOW LEVELS...LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED WITH ONLY SLIGHT CHANCE POPS INCLUDED. SNOW CHANCES WILL INCREASE OVERNIGHT AS 700-300 MB QVECTOR CONV AHEAD OF THE SHORTWAVE MOVES IN BUT SNOW AMOUNTS SHOULD REMAIN LESS THAN A HALF INCH. SW FLOW LAKE ENHANCEMENT IS LIKELY TO DEVELOP OFF OF LAKE MICHIGAN BUT THE LOW LEVEL WINDS VEER ENOUGH TO KEEP THE HIGHER SNOW CHANCES/AMOUNTS TO THE SOUTH AND EAST OF SCHOOLCRAFT AND LUCE COUNTIES. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 440 AM EST SUN NOV 24 2013 NORTHERN STREAM REMAINS ACTIVE THROUGH THE WEEK KEEPING THE COLD ACROSS THE GREAT LAKES. NEXT CHARGE OF ARCTIC AIR ARRIVES LATER MONDAY NIGHT INTO TUESDAY. LK EFFECT SNOW INCREASES MONDAY NIGHT THROUGH TUESDAY NIGHT. AFTER HIGH PRESSURE RIDGE/SUBSIDENCE BRINGS DIMINISHING TREND TO LK EFFECT LATER WEDNESDAY...ANOTHER SHORTWAVE DROPPING THROUGH MAY BRING SOME LGT SNOW FOR THANKSGIVING DAY. AGREEMENT FALLS OFF BY NEXT WEEKEND WITH THE ECMWF KEEPING A NW FLOW ALOFT ACROSS GREAT LAKES AND BRINGING ANOTHER CLIPPER THROUGH ON SATURDAY. GFS IS SLOWER AND MORE DEVELOPED BUT FARTHER NORTH WITH NEXT TROUGH DROPPING THROUGH BY LATE IN THE WEEKEND. MODELS IN OKAY AGREEMENT THROUGH 12Z TUESDAY THEN THEY BEGIN TO SHOW DIFFERENCES. OVERALL THOUGH EVEN THE DISAGREEMENT...SPEED OF INITIAL SHORTWAVE MOVING THROUGH UPR LAKES...DOES NOT HAVE HUGE IMPACTS ON THE OVERALL THEME OF FORECAST. GFS ENDS UP BEING QUICKER THAN ECMWF/NAM AND GEM-NH WITH HANDLING OF INITIAL SHORTWAVE. PLAN IS THAT ON MONDAY MORNING SHORTWAVE WILL BE NORTH OF LK SUPERIOR WITH TROUGH AXIS DROPPING ACROSS UPR LAKES. SFC LOW/H85 LOW AND SFC TROUGH SWINGS ACROSS WESTERN UPR MICHIGAN BY MIDDAY AND INTO THE EASTERN CWA BY EVENING. MAY SEE LGT LK EFFECT WITH MARGINAL TEMPS AT INVERSION TOP MOST OF THE DAY OVER THE WEST...BETTER CHANCES WILL BE LATER ON THOUGH. HINT THAT WEAK WAVE IN THE SOUTHERN STREAM SLIDES WSW-ENE ACROSS MAINLY SOUTHERN SECTIONS OF WESTERN GREAT LAKES AND INTERACTS WITH H8-H7 FRONTOGENESIS AND RIGHT ENTRANCE REGION OF JET FM CNTRL GREAT LAKES TO SOUTHERN QUEBEC MONDAY MORNING THROUGH MID MONDAY AFTN. SOME LGT SYNOPTIC SNOW MAY SCRAPE LK MICHIGAN ZONES AND FAR EAST. IF THERE IS ENOUGH LOW-LEVEL MOISTURE TO START THE DAY...COULD EVEN SEE A BIT OF FZDZ ALONG WI BORDER AS DEEPER MOISTURE HEADS EAST. LAKE ENHANCEMENT EXPECTED OFF LK MICHIGAN WITH SW FLOW AS H85 TEMPS ARE AROUND -8C. SHOULD STAY EAST OF CWA THOUGH AS WINDS ARE FM SW INSTEAD OF SSW OR S. FARTHER WEST...LK EFFECT SHOULD INCREASE LATER AFTN OVER WESTERN THIRD OF CWA AS SYNOPTIC LIFT /-DIV-Q AT H7-H5/ FM APPROACHING SHORTWAVE COMBINES WITH WNW WINDS THROUGH H85 AND TEMPS AT H85 OF -8C YIELDING DELTA T/S UP TO 12C. INSTABILITY IS MARGINAL AND THUS EXPECT ONLY MINOR SNOW ACCUMS THROUGH 00Z TUESDAY IN THE WEST. MONDAY NIGHT INTO TUESDAY HOLDS GREATEST CHANCE FOR MODERATE TO HEAVY LK EFFECT SNOW SHOWERS. OVERALL EXPECT MOST SNOW TO OCCUR FOR AREAS FAVORED BY NNW WINDS THROUGH TUESDAY AND THEN SHIFT TO AREAS FAVORED BY N OR NE WINDS ON TUESDAY NIGHT. UNLIKE THIS LAST EVENT WHERE SNOWFALL AMOUNTS ENDED UP ON THE LOWER END OF FCST FOR MOST AREAS...SHORTWAVE/ADDITIONAL SYNOPTIC MOISTURE IS FCST TO IMPACT UPR LAKES DURING THE TIME OF THE LAKE EFFECT...ESPECIALLY THROUGH TUESDAY. AT THE LEAST...EXPECT ADVY TYPE SNOWS WILL OCCUR FOR MAINLY NNW-NW FLOW AREAS MONDAY NIGHT INTO TUESDAY. LACK OF PERSISTENT UNIDIRECTIONAL FLOW IN LAKE EFFECT CONVECTIVE LAYER WILL LIMIT SNOW AMOUNTS THOUGH THIS WILL PROBABLY BE OFFSET BY THE SHORTWAVE/DEEPER MOISTURE. SEEMS LIKE HIGHER TERRAIN FROM IRONWOOD TO ROCKLAND TO PAINESDALE AND ATLANTIC MINE WILL SEE THE MOST SNOW OVER THE WEST WHILE FAVORED SNOWBELTS FROM EAST OF MARQUETTE TO NEWBERRY... INCLUDING MOST OF ALGER COUNTY AND ALONG AND NORTH OF THE SENEY STRETCH IN SCHOOLCRAFT COUNTY...WILL SEE THE MOST SNOW OVER THE CNTRL AND EASTERN CWA. UNLIKE THIS LAST EVENT...WINDS SEEM MORE CERTAIN TO VEER ENOUGH NORTHERLY TO ALLOW FOR LK EFFECT SNOWS TO IMPACT NCNTRL UPR MICHIGAN /HIGHER TERRAIN OF BARAGA AND MARQUETTE COUNTIES/ LATER TUESDAY INTO TUESDAY NIGHT AND PERHAPS LINGERING INTO MOST OF WEDNESDAY. INVERSIONS LOWERING BLO 5KFT AND WINDS BECOMING VARIABLE WILL DIMINISH SNOW OVER FAR WEST BY WEDNESDAY AFTN. A LIGHT BUT PERSISTENT N-NE WIND MAY KEEP WEAKENING SNOW SHOWERS GOING THROUGH MOST OF THE NIGHT BTWN MQT AND MUNISING. LIGHTER WINDS PROBABLY WILL KEEP MOST OF SNOW SHOWERS RIGHT ALONG IMMEDIATE SHORE WITH SKIES TRYING TO CLEAR OUT INLAND. SHORTWAVE AND ARC OF WARM AIR ADVECTION/MOISTURE ADVECTION COULD SPUR ON BATCH OF LGT SNOW ACROSS MAINLY NORTHERN CWA DURING THE DAY ON THANKSGIVING. LIMITED MOISTURE WITH PWATS LESS THAN 100 PCT OF NORMAL AND FOCUS OF STRONGER LIFT FM SHORTWAVE STAYING NORTH OF LK SUPERIOR SHOULD LIMIT SNOW AMOUNTS. TROUGH SWINGING ACROSS NORTHERN UPR MICHIGAN MAY KICK OFF SOME SNOW SHOWERS ACROSS KEWEENAW LATER THURSDAY NIGHT INTO FRIDAY. CONSENSUS GIVES LOW CHANCE POPS BEYOND FRIDAY WHICH IS FINE GIVEN DIFFERENCES IN TRACK OF SHORTWAVE/SFC SYSTEM THAT GFS/ECMWF INDICATE MOVES THROUGH THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1210 PM EST SUN NOV 24 2013 VFR CONDITIONS WILL CONTINUE THROUGH MOST OF TONIGHT AT ALL SITES AS HIGH PRESSURE IS OVER THE AREA. THE PRESSURE GRADIENT OVER THE AREA WILL TIGHTEN THIS AFTERNOON AND EVENING...SO EXPECT A GUSTY WIND TO DEVELOP AT THE MORE EXPOSED IWD AND SAW LOCATIONS. MVFR CONDITIONS WILL RETURN LATE TONIGHT AS LOW LEVEL MOISTURE INCREASES AHEAD OF A TROUGH APPROACHING THE AREA AT CMX AND IWD AND WILL RETURN MON MORNING AT SAW. DID PUT IN SOME LLWS AT IWD TONIGHT WITH STRONG WINDS OFF THE SURFACE. WILL GET QUITE GUSTY AT CMX WITH FAVORABLE WEST WINDS MONDAY MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EST SUN NOV 24 2013 NW WINDS TO 25 KTS DIMINISH THIS MORNING THEN SHIFT TO THE SW AND INCREASE TO 30 KTS THIS EVENING. GALES EXPECTED OVR SUPERIOR ZONE 263 TONIGHT DUE TO CHANNELED FLOW BTWN KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO TUESDAY AND REMAIN UP TO 30 KTS. FREEZING SPRAY MAY OCCUR LATER MONDAY INTO TUESDAY AS ANOTHER PUSH OF COLDER AIR CROSSES LK SUPERIOR. GALE GUSTS POSSIBLE AS THE COLDER AIR FIRST ARRIVES. EVENTUALLY WINDS BECOME NORTHERLY TUESDAY NIGHT INTO WEDNESDAY THEN DIMINISH TO LESS THAN 20 KTS THROUGH THE REST OF THE WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 5 PM THIS AFTERNOON TO 8 AM EST MONDAY FOR LSZ263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
659 AM EST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 526 AM EST SUN NOV 24 2013 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES WITH GRADUALLY RISING HEIGHTS AS THE TROUGH OVER THE NE CONUS SLIDES TO THE EAST AND MID LEVEL RIDGING BUILDS TOWARD THE AREA FROM SOUTH CENTRAL CANADA. AT THE SFC...A RIDGE WAS BUILDING FROM NW WI AND WRN LAKE SUPERIOR INTO FAR W UPPER MI WHILE LAKE INDUCED TROUGHING PREVAILED THROUGH ERN LAKE SUPERIOR. SATELLITE AND RADAR INDICATED NW-SE ALIGNED WIND PARALLEL LES BANDS HAD SHIFTED INTO LOCATIONS E OF MARQUETTE COUNTY. THE BANDS HAD ALSO BECOME MORE CELLULAR WITH GRADUALLY DECREASING INTENSITY OVERNIGHT. SFC OBS STILL INDICATED INTO W UPPER MI WITH CMX SHOWING VSBY IN THE 1-3SM RANGE. HOWEVER...WEBCAMS FROM HOUGHTON AND CALUMET SHOWED LITTLE SNOW OR VSBY REDUCTION. THIS MORNING... DESPITE 850 MB TEMPS AROUND -20C...INVERSION HEIGHTS DROPPING BELOW 5K FT AND VERY DRY AIR UPSTREAM WILL CONTINUE TO LIMIT LES INTENSITY...ESPECIALLY OVER THE WEST. DIMINISHING WINDS WITH AN INCREASED LAND BREEZE INFLUENCE AND A BACKING TREND WITH THE APPROACHING RIDGE WILL RESULT IN A PERIOD OF ENHANCED CONVERGENCE FROM ERN LAKE SUPERIOR INTO UPPER MI BETWEEN MUNISING AND NEWBERRY WHERE ADDITIONAL SNOW AMOUNTS IN THE 1 TO 3 INCH RANGE ARE EXPECTED THROUGH THE MORNING. THE BACKING WINDS SHOULD PUSH THE REMAINING LES OFFSHORE IN THE AFTERNOON. THIS AFTERNOON AND TONIGHT... DEVELOPING WAA WITH STRONG 280K-295K PRES ADV BUT ONLY WEAK TO MODERATE NET LIFT AHEAD OF A SHRTWV AND SFC LOW MOVING INTO CNTRL MANITOBA MAY LEAD TO AN AREA OF LIGHT SNOW STREAKING SE INTO THE NORTH AND EAST PORTIONS OF UPPER MI LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH THE DRY LOW LEVELS...LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED WITH ONLY SLIGHT CHANCE POPS INCLUDED. SNOW CHANCES WILL INCREASE OVERNIGHT AS 700-300 MB QVECTOR CONV AHEAD OF THE SHORTWAVE MOVES IN BUT SNOW AMOUNTS SHOULD REMAIN LESS THAN A HALF INCH. SW FLOW LAKE ENHANCEMENT IS LIKELY TO DEVELOP OFF OF LAKE MICHIGAN BUT THE LOW LEVEL WINDS VEER ENOUGH TO KEEP THE HIGHER SNOW CHANCES/AMOUNTS TO THE SOUTH AND EAST OF SCHOOLCRAFT AND LUCE COUNTIES. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 440 AM EST SUN NOV 24 2013 NORTHERN STREAM REMAINS ACTIVE THROUGH THE WEEK KEEPING THE COLD ACROSS THE GREAT LAKES. NEXT CHARGE OF ARCTIC AIR ARRIVES LATER MONDAY NIGHT INTO TUESDAY. LK EFFECT SNOW INCREASES MONDAY NIGHT THROUGH TUESDAY NIGHT. AFTER HIGH PRESSURE RIDGE/SUBSIDENCE BRINGS DIMINISHING TREND TO LK EFFECT LATER WEDNESDAY...ANOTHER SHORTWAVE DROPPING THROUGH MAY BRING SOME LGT SNOW FOR THANKSGIVING DAY. AGREEMENT FALLS OFF BY NEXT WEEKEND WITH THE ECMWF KEEPING A NW FLOW ALOFT ACROSS GREAT LAKES AND BRINGING ANOTHER CLIPPER THROUGH ON SATURDAY. GFS IS SLOWER AND MORE DEVELOPED BUT FARTHER NORTH WITH NEXT TROUGH DROPPING THROUGH BY LATE IN THE WEEKEND. MODELS IN OKAY AGREEMENT THROUGH 12Z TUESDAY THEN THEY BEGIN TO SHOW DIFFERENCES. OVERALL THOUGH EVEN THE DISAGREEMENT...SPEED OF INITIAL SHORTWAVE MOVING THROUGH UPR LAKES...DOES NOT HAVE HUGE IMPACTS ON THE OVERALL THEME OF FORECAST. GFS ENDS UP BEING QUICKER THAN ECMWF/NAM AND GEM-NH WITH HANDLING OF INITIAL SHORTWAVE. PLAN IS THAT ON MONDAY MORNING SHORTWAVE WILL BE NORTH OF LK SUPERIOR WITH TROUGH AXIS DROPPING ACROSS UPR LAKES. SFC LOW/H85 LOW AND SFC TROUGH SWINGS ACROSS WESTERN UPR MICHIGAN BY MIDDAY AND INTO THE EASTERN CWA BY EVENING. MAY SEE LGT LK EFFECT WITH MARGINAL TEMPS AT INVERSION TOP MOST OF THE DAY OVER THE WEST...BETTER CHANCES WILL BE LATER ON THOUGH. HINT THAT WEAK WAVE IN THE SOUTHERN STREAM SLIDES WSW-ENE ACROSS MAINLY SOUTHERN SECTIONS OF WESTERN GREAT LAKES AND INTERACTS WITH H8-H7 FRONTOGENESIS AND RIGHT ENTRANCE REGION OF JET FM CNTRL GREAT LAKES TO SOUTHERN QUEBEC MONDAY MORNING THROUGH MID MONDAY AFTN. SOME LGT SYNOPTIC SNOW MAY SCRAPE LK MICHIGAN ZONES AND FAR EAST. IF THERE IS ENOUGH LOW-LEVEL MOISTURE TO START THE DAY...COULD EVEN SEE A BIT OF FZDZ ALONG WI BORDER AS DEEPER MOISTURE HEADS EAST. LAKE ENHANCEMENT EXPECTED OFF LK MICHIGAN WITH SW FLOW AS H85 TEMPS ARE AROUND -8C. SHOULD STAY EAST OF CWA THOUGH AS WINDS ARE FM SW INSTEAD OF SSW OR S. FARTHER WEST...LK EFFECT SHOULD INCREASE LATER AFTN OVER WESTERN THIRD OF CWA AS SYNOPTIC LIFT /-DIV-Q AT H7-H5/ FM APPROACHING SHORTWAVE COMBINES WITH WNW WINDS THROUGH H85 AND TEMPS AT H85 OF -8C YIELDING DELTA T/S UP TO 12C. INSTABILITY IS MARGINAL AND THUS EXPECT ONLY MINOR SNOW ACCUMS THROUGH 00Z TUESDAY IN THE WEST. MONDAY NIGHT INTO TUESDAY HOLDS GREATEST CHANCE FOR MODERATE TO HEAVY LK EFFECT SNOW SHOWERS. OVERALL EXPECT MOST SNOW TO OCCUR FOR AREAS FAVORED BY NNW WINDS THROUGH TUESDAY AND THEN SHIFT TO AREAS FAVORED BY N OR NE WINDS ON TUESDAY NIGHT. UNLIKE THIS LAST EVENT WHERE SNOWFALL AMOUNTS ENDED UP ON THE LOWER END OF FCST FOR MOST AREAS...SHORTWAVE/ADDITIONAL SYNOPTIC MOISTURE IS FCST TO IMPACT UPR LAKES DURING THE TIME OF THE LAKE EFFECT...ESPECIALLY THROUGH TUESDAY. AT THE LEAST...EXPECT ADVY TYPE SNOWS WILL OCCUR FOR MAINLY NNW-NW FLOW AREAS MONDAY NIGHT INTO TUESDAY. LACK OF PERSISTENT UNIDIRECTIONAL FLOW IN LAKE EFFECT CONVECTIVE LAYER WILL LIMIT SNOW AMOUNTS THOUGH THIS WILL PROBABLY BE OFFSET BY THE SHORTWAVE/DEEPER MOISTURE. SEEMS LIKE HIGHER TERRAIN FROM IRONWOOD TO ROCKLAND TO PAINESDALE AND ATLANTIC MINE WILL SEE THE MOST SNOW OVER THE WEST WHILE FAVORED SNOWBELTS FROM EAST OF MARQUETTE TO NEWBERRY... INCLUDING MOST OF ALGER COUNTY AND ALONG AND NORTH OF THE SENEY STRETCH IN SCHOOLCRAFT COUNTY...WILL SEE THE MOST SNOW OVER THE CNTRL AND EASTERN CWA. UNLIKE THIS LAST EVENT...WINDS SEEM MORE CERTAIN TO VEER ENOUGH NORTHERLY TO ALLOW FOR LK EFFECT SNOWS TO IMPACT NCNTRL UPR MICHIGAN /HIGHER TERRAIN OF BARAGA AND MARQUETTE COUNTIES/ LATER TUESDAY INTO TUESDAY NIGHT AND PERHAPS LINGERING INTO MOST OF WEDNESDAY. INVERSIONS LOWERING BLO 5KFT AND WINDS BECOMING VARIABLE WILL DIMINISH SNOW OVER FAR WEST BY WEDNESDAY AFTN. A LIGHT BUT PERSISTENT N-NE WIND MAY KEEP WEAKENING SNOW SHOWERS GOING THROUGH MOST OF THE NIGHT BTWN MQT AND MUNISING. LIGHTER WINDS PROBABLY WILL KEEP MOST OF SNOW SHOWERS RIGHT ALONG IMMEDIATE SHORE WITH SKIES TRYING TO CLEAR OUT INLAND. SHORTWAVE AND ARC OF WARM AIR ADVECTION/MOISTURE ADVECTION COULD SPUR ON BATCH OF LGT SNOW ACROSS MAINLY NORTHERN CWA DURING THE DAY ON THANKSGIVING. LIMITED MOISTURE WITH PWATS LESS THAN 100 PCT OF NORMAL AND FOCUS OF STRONGER LIFT FM SHORTWAVE STAYING NORTH OF LK SUPERIOR SHOULD LIMIT SNOW AMOUNTS. TROUGH SWINGING ACROSS NORTHERN UPR MICHIGAN MAY KICK OFF SOME SNOW SHOWERS ACROSS KEWEENAW LATER THURSDAY NIGHT INTO FRIDAY. CONSENSUS GIVES LOW CHANCE POPS BEYOND FRIDAY WHICH IS FINE GIVEN DIFFERENCES IN TRACK OF SHORTWAVE/SFC SYSTEM THAT GFS/ECMWF INDICATE MOVES THROUGH THE AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 658 AM EST SUN NOV 24 2013 AS HIGH PRES OVER NRN MO SHIFTS TO THE SE...EXPECT LOW LEVEL WINDS TO BACK FROM THETHE W-NW EARLY THIS MORNING TO THE SW THIS AFTERNOON. SINCE THIS FLOW DOWNSLOPES INTO SAW...VFR CONDITIONS SHOULD PREDOMINATE. THE BEST CHC FOR MORE PERSISTENT MVFR CONDITIONS WILL BE AT CMX AS THE NW TO W WIND WL UPSLOPE AFTER A LONGER FETCH/MORE MOISTENING OVER LAKE SUPERIOR. BUT AS THE WIND SHIFTS TO THE SW...VFR WX WILL TAKE OVER AT CMX EVEN THOUGH SOME FLURRIES/-SN MAY FALL FROM A THICKENING MID CLOUD DECK RELATED TO THE RETURN OF WARMER AIR. THE PRES GRADIENT OVER WRN UPPER MI WILL SHARPEN THIS AFTERNOON AND EVENING...SO EXPECT A GUSTY WIND TO DEVEOP AT THE MORE EXPOSED IWD AND SAW LOCATIONS. MVFR CONDITIONS MAY RETURN LATE TONIGHT AS LOW LEVEL MOISTURE INCREASES AHEAD OF A TROUGH APPROACHING THE AREA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EST SUN NOV 24 2013 NW WINDS TO 25 KTS DIMINISH THIS MORNING THEN SHIFT TO THE SW AND INCREASE TO 30 KTS THIS EVENING. GALES EXPECTED OVR SUPERIOR ZONE 263 TONIGHT DUE TO CHANNELED FLOW BTWN KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO TUESDAY AND REMAIN UP TO 30 KTS. FREEZING SPRAY MAY OCCUR LATER MONDAY INTO TUESDAY AS ANOTHER PUSH OF COLDER AIR CROSSES LK SUPERIOR. GALE GUSTS POSSIBLE AS THE COLDER AIR FIRST ARRIVES. EVENTUALLY WINDS BECOME NORTHERLY TUESDAY NIGHT INTO WEDNESDAY THEN DIMINISH TO LESS THAN 20 KTS THROUGH THE REST OF THE WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL NOON EST TODAY FOR MIZ006-007- 085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001>003. LAKE SUPERIOR... GALE WARNING FROM 5 PM THIS AFTERNOON TO 8 AM EST MONDAY FOR LSZ263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
530 AM EST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 526 AM EST SUN NOV 24 2013 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW THROUGH THE NRN GREAT LAKES WITH GRADUALLY RISING HEIGHTS AS THE TROUGH OVER THE NE CONUS SLIDES TO THE EAST AND MID LEVEL RIDGING BUILDS TOWARD THE AREA FROM SOUTH CENTRAL CANADA. AT THE SFC...A RIDGE WAS BUILDING FROM NW WI AND WRN LAKE SUPERIOR INTO FAR W UPPER MI WHILE LAKE INDUCED TROUGHING PREVAILED THROUGH ERN LAKE SUPERIOR. SATELLITE AND RADAR INDICATED NW-SE ALIGNED WIND PARALLEL LES BANDS HAD SHIFTED INTO LOCATIONS E OF MARQUETTE COUNTY. THE BANDS HAD ALSO BECOME MORE CELLULAR WITH GRADUALLY DECREASING INTENSITY OVERNIGHT. SFC OBS STILL INDICATED INTO W UPPER MI WITH CMX SHOWING VSBY IN THE 1-3SM RANGE. HOWEVER...WEBCAMS FROM HOUGHTON AND CALUMET SHOWED LITTLE SNOW OR VSBY REDUCTION. THIS MORNING... DESPITE 850 MB TEMPS AROUND -20C...INVERSION HEIGHTS DROPPING BELOW 5K FT AND VERY DRY AIR UPSTREAM WILL CONTINUE TO LIMIT LES INTENSITY...ESPECIALLY OVER THE WEST. DIMINISHING WINDS WITH AN INCREASED LAND BREEZE INFLUENCE AND A BACKING TREND WITH THE APPROACHING RIDGE WILL RESULT IN A PERIOD OF ENHANCED CONVERGENCE FROM ERN LAKE SUPERIOR INTO UPPER MI BETWEEN MUNISING AND NEWBERRY WHERE ADDITIONAL SNOW AMOUNTS IN THE 1 TO 3 INCH RANGE ARE EXPECTED THROUGH THE MORNING. THE BACKING WINDS SHOULD PUSH THE REMAINING LES OFFSHORE IN THE AFTERNOON. THIS AFTERNOON AND TONIGHT... DEVELOPING WAA WITH STRONG 280K-295K PRES ADV BUT ONLY WEAK TO MODERATE NET LIFT AHEAD OF A SHRTWV AND SFC LOW MOVING INTO CNTRL MANITOBA MAY LEAD TO AN AREA OF LIGHT SNOW STREAKING SE INTO THE NORTH AND EAST PORTIONS OF UPPER MI LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH THE DRY LOW LEVELS...LITTLE IF ANY SNOW ACCUMULATION IS EXPECTED WITH ONLY SLIGHT CHANCE POPS INCLUDED. SNOW CHANCES WILL INCREASE OVERNIGHT AS 700-300 MB QVECTOR CONV AHEAD OF THE SHORTWAVE MOVES IN BUT SNOW AMOUNTS SHOULD REMAIN LESS THAN A HALF INCH. SW FLOW LAKE ENHANCEMENT IS LIKELY TO DEVELOP OFF OF LAKE MICHIGAN BUT THE LOW LEVEL WINDS VEER ENOUGH TO KEEP THE HIGHER SNOW CHANCES/AMOUNTS TO THE SOUTH AND EAST OF SCHOOLCRAFT AND LUCE COUNTIES. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 440 AM EST SUN NOV 24 2013 NORTHERN STREAM REMAINS ACTIVE THROUGH THE WEEK KEEPING THE COLD ACROSS THE GREAT LAKES. NEXT CHARGE OF ARCTIC AIR ARRIVES LATER MONDAY NIGHT INTO TUESDAY. LK EFFECT SNOW INCREASES MONDAY NIGHT THROUGH TUESDAY NIGHT. AFTER HIGH PRESSURE RIDGE/SUBSIDENCE BRINGS DIMINISHING TREND TO LK EFFECT LATER WEDNESDAY...ANOTHER SHORTWAVE DROPPING THROUGH MAY BRING SOME LGT SNOW FOR THANKSGIVING DAY. AGREEMENT FALLS OFF BY NEXT WEEKEND WITH THE ECMWF KEEPING A NW FLOW ALOFT ACROSS GREAT LAKES AND BRINGING ANOTHER CLIPPER THROUGH ON SATURDAY. GFS IS SLOWER AND MORE DEVELOPED BUT FARTHER NORTH WITH NEXT TROUGH DROPPING THROUGH BY LATE IN THE WEEKEND. MODELS IN OKAY AGREEMENT THROUGH 12Z TUESDAY THEN THEY BEGIN TO SHOW DIFFERENCES. OVERALL THOUGH EVEN THE DISAGREEMENT...SPEED OF INITIAL SHORTWAVE MOVING THROUGH UPR LAKES...DOES NOT HAVE HUGE IMPACTS ON THE OVERALL THEME OF FORECAST. GFS ENDS UP BEING QUICKER THAN ECMWF/NAM AND GEM-NH WITH HANDLING OF INITIAL SHORTWAVE. PLAN IS THAT ON MONDAY MORNING SHORTWAVE WILL BE NORTH OF LK SUPERIOR WITH TROUGH AXIS DROPPING ACROSS UPR LAKES. SFC LOW/H85 LOW AND SFC TROUGH SWINGS ACROSS WESTERN UPR MICHIGAN BY MIDDAY AND INTO THE EASTERN CWA BY EVENING. MAY SEE LGT LK EFFECT WITH MARGINAL TEMPS AT INVERSION TOP MOST OF THE DAY OVER THE WEST...BETTER CHANCES WILL BE LATER ON THOUGH. HINT THAT WEAK WAVE IN THE SOUTHERN STREAM SLIDES WSW-ENE ACROSS MAINLY SOUTHERN SECTIONS OF WESTERN GREAT LAKES AND INTERACTS WITH H8-H7 FRONTOGENESIS AND RIGHT ENTRANCE REGION OF JET FM CNTRL GREAT LAKES TO SOUTHERN QUEBEC MONDAY MORNING THROUGH MID MONDAY AFTN. SOME LGT SYNOPTIC SNOW MAY SCRAPE LK MICHIGAN ZONES AND FAR EAST. IF THERE IS ENOUGH LOW-LEVEL MOISTURE TO START THE DAY...COULD EVEN SEE A BIT OF FZDZ ALONG WI BORDER AS DEEPER MOISTURE HEADS EAST. LAKE ENHANCEMENT EXPECTED OFF LK MICHIGAN WITH SW FLOW AS H85 TEMPS ARE AROUND -8C. SHOULD STAY EAST OF CWA THOUGH AS WINDS ARE FM SW INSTEAD OF SSW OR S. FARTHER WEST...LK EFFECT SHOULD INCREASE LATER AFTN OVER WESTERN THIRD OF CWA AS SYNOPTIC LIFT /-DIV-Q AT H7-H5/ FM APPROACHING SHORTWAVE COMBINES WITH WNW WINDS THROUGH H85 AND TEMPS AT H85 OF -8C YIELDING DELTA T/S UP TO 12C. INSTABILITY IS MARGINAL AND THUS EXPECT ONLY MINOR SNOW ACCUMS THROUGH 00Z TUESDAY IN THE WEST. MONDAY NIGHT INTO TUESDAY HOLDS GREATEST CHANCE FOR MODERATE TO HEAVY LK EFFECT SNOW SHOWERS. OVERALL EXPECT MOST SNOW TO OCCUR FOR AREAS FAVORED BY NNW WINDS THROUGH TUESDAY AND THEN SHIFT TO AREAS FAVORED BY N OR NE WINDS ON TUESDAY NIGHT. UNLIKE THIS LAST EVENT WHERE SNOWFALL AMOUNTS ENDED UP ON THE LOWER END OF FCST FOR MOST AREAS...SHORTWAVE/ADDITIONAL SYNOPTIC MOISTURE IS FCST TO IMPACT UPR LAKES DURING THE TIME OF THE LAKE EFFECT...ESPECIALLY THROUGH TUESDAY. AT THE LEAST...EXPECT ADVY TYPE SNOWS WILL OCCUR FOR MAINLY NNW-NW FLOW AREAS MONDAY NIGHT INTO TUESDAY. LACK OF PERSISTENT UNIDIRECTIONAL FLOW IN LAKE EFFECT CONVECTIVE LAYER WILL LIMIT SNOW AMOUNTS THOUGH THIS WILL PROBABLY BE OFFSET BY THE SHORTWAVE/DEEPER MOISTURE. SEEMS LIKE HIGHER TERRAIN FROM IRONWOOD TO ROCKLAND TO PAINESDALE AND ATLANTIC MINE WILL SEE THE MOST SNOW OVER THE WEST WHILE FAVORED SNOWBELTS FROM EAST OF MARQUETTE TO NEWBERRY... INCLUDING MOST OF ALGER COUNTY AND ALONG AND NORTH OF THE SENEY STRETCH IN SCHOOLCRAFT COUNTY...WILL SEE THE MOST SNOW OVER THE CNTRL AND EASTERN CWA. UNLIKE THIS LAST EVENT...WINDS SEEM MORE CERTAIN TO VEER ENOUGH NORTHERLY TO ALLOW FOR LK EFFECT SNOWS TO IMPACT NCNTRL UPR MICHIGAN /HIGHER TERRAIN OF BARAGA AND MARQUETTE COUNTIES/ LATER TUESDAY INTO TUESDAY NIGHT AND PERHAPS LINGERING INTO MOST OF WEDNESDAY. INVERSIONS LOWERING BLO 5KFT AND WINDS BECOMING VARIABLE WILL DIMINISH SNOW OVER FAR WEST BY WEDNESDAY AFTN. A LIGHT BUT PERSISTENT N-NE WIND MAY KEEP WEAKENING SNOW SHOWERS GOING THROUGH MOST OF THE NIGHT BTWN MQT AND MUNISING. LIGHTER WINDS PROBABLY WILL KEEP MOST OF SNOW SHOWERS RIGHT ALONG IMMEDIATE SHORE WITH SKIES TRYING TO CLEAR OUT INLAND. SHORTWAVE AND ARC OF WARM AIR ADVECTION/MOISTURE ADVECTION COULD SPUR ON BATCH OF LGT SNOW ACROSS MAINLY NORTHERN CWA DURING THE DAY ON THANKSGIVING. LIMITED MOISTURE WITH PWATS LESS THAN 100 PCT OF NORMAL AND FOCUS OF STRONGER LIFT FM SHORTWAVE STAYING NORTH OF LK SUPERIOR SHOULD LIMIT SNOW AMOUNTS. TROUGH SWINGING ACROSS NORTHERN UPR MICHIGAN MAY KICK OFF SOME SNOW SHOWERS ACROSS KEWEENAW LATER THURSDAY NIGHT INTO FRIDAY. CONSENSUS GIVES LOW CHANCE POPS BEYOND FRIDAY WHICH IS FINE GIVEN DIFFERENCES IN TRACK OF SHORTWAVE/SFC SYSTEM THAT GFS/ECMWF INDICATE MOVES THROUGH THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN NOV 24 2013 AS HI PRES OVER IOWA SHIFTS STEADILY TO THE SE DURING THIS PERIOD... EXPECT LLVL WINDS TO BACK FM THE W-NW EARLY THIS MRNG TO THE SW BY THIS AFTN. ALTHOUGH SOME LINGERING LES MAY BRING MVFR CONDITIONS TO IWD EARLY IN THE PERIOD UNDER LINGERING WNW FLOW...MINIMAL LK SUP MOISTENING OF THE DRY ARCTIC AIRMASS WL ENSURE PREDOMINANT VFR CONDITIONS FOR THAT LOCATION. SINCE THIS FLOW DOWNSLOPES INTO SAW...VFR CONDITIONS SHOULD PREDOMINATE THERE AS WELL. THE BEST CHC FOR MORE PERSISTENT MVFR TO PERHAPS IFR CONDITIONS WL BE AT CMX THRU SUNRISE AS THE NW TO W WIND WL UPSLOPE AFT A LONGER FETCH/MORE MOISTENING OVER LK SUP. BUT AS THE WIND SHIFTS TO THE SW ON SUN... VFR WX WL THE RULE AT CMX AS WELL EVEN THOUGH SOME FLURRIES/-SN MAY FALL FM A THICKENING MID CLD DECK RELATED TO THE RETURN OF WARMER AIR. THE PRES GRADIENT OVER WRN UPR MI WL SHARPEN ON SUN AFTN/ EVNG...SO EXPECT A GUSTY WIND TO DVLP AT THE MORE EXPOSED IWD AND SAW LOCATIONS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 440 AM EST SUN NOV 24 2013 NW WINDS TO 25 KTS DIMINISH THIS MORNING THEN SHIFT TO THE SW AND INCREASE TO 30 KTS THIS EVENING. GALES EXPECTED OVR SUPERIOR ZONE 263 TONIGHT DUE TO CHANNELED FLOW BTWN KEWEENAW AND ISLE ROYALE. WINDS TURN TO NORTHWEST ON MONDAY INTO TUESDAY AND REMAIN UP TO 30 KTS. FREEZING SPRAY MAY OCCUR LATER MONDAY INTO TUESDAY AS ANOTHER PUSH OF COLDER AIR CROSSES LK SUPERIOR. GALE GUSTS POSSIBLE AS THE COLDER AIR FIRST ARRIVES. EVENTUALLY WINDS BECOME NORTHERLY TUESDAY NIGHT INTO WEDNESDAY THEN DIMINISH TO LESS THAN 20 KTS THROUGH THE REST OF THE WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL NOON EST TODAY FOR MIZ006-007- 085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001>003. LAKE SUPERIOR... GALE WARNING FROM 5 PM THIS AFTERNOON TO 8 AM EST MONDAY FOR LSZ263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...JLA
AREA FORECAST DISCUSSION
NWS DULUTH MN
903 AM CST SUN NOV 24 2013 .UPDATE... ISSUED AT 902 AM CST SUN NOV 24 2013 MADE SOME ADJUSTMENTS TO REMOVE THE MENTION OF FLURRIES THIS AFTERNOON. RH IN THE 1000MB-500MB RANGE IS LESS THAN 50 PERCENT IN ALL AREAS EXCEPT WHERE THERE IS A MENTION OF ISOLD/SCT SNOW SHOWERS NEAR THE INTERNATIONAL BORDER AND OVER THE ARROWHEAD. REST OF THE FORECAST ON TRACK. && .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 400 AM CST SUN NOV 24 2013 A STRONG PUSH OF WARM AIR ADVECTION WILL OVERTAKE THE REGION TODAY AS A LOW LEVEL TROUGH SWEEPS ACROSS THE DAKOTAS. LATEST MODELS IN GOOD AGREEMENT THAT H85 TEMPS INCREASE ON THE ODER OF >10 C THROUGH THE DAY AS A LOW LEVEL JET STREAK OF 40-50 KT WLY WINDS ADVECT ACROSS CENTRAL MN. AFTERNOON TEMPERATURES WILL RETURN TO MORE SEASONAL VALUES TODAY...IN THE MID TO UPPER 20S. A FAST MOVING VORT MAX WILL SLIDE ALONG THE INTERNATIONAL BORDER THIS MORNING...REACHING THE MN ARROWHEAD ZONES THIS AFTERNOON. THE COMBINATION OF MID LEVEL OMEGA IN THE DENDRITIC GROWTH ZONE...AND LAKE EFFECT/ENHANCEMENT FROM THE STRONG S/SW BOUNDARY LAYER WINDS WILL PRODUCE A QUICK INCH OR SO ALONG THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE MAIN CORRIDOR OF SNOW ACCUMULATION WILL BE ALONG HIGHWAY 61 FROM SILVER BAY...TO LUTSEN...GRAND MARAIS AND GRAND PORTAGE. LOCATIONS IN THE ELEVATED TERRAIN OF COOK COUNTY...A FEW MILES INLAND FROM LAKE SUPERIOR...CAN EXPECT LOCALLY HIGHER AMOUNTS AROUND 2 INCHES DUE TO ENHANCED OROGRAPHIC LIFT. FOCUS TURNS TO THREAT FOR FREEZING DRIZZLE OVERNIGHT AHEAD OF FRONTAL PASSAGE. LATEST NAM BUFR SOUNDINGS ACROSS MUCH THE NORTHLAND SHOW PROFILES WITH A DEEP SATURATED LAYER...AND CLOUD TOP TEMPERATURES IN THE SINGLE DIGITS BELOW ZERO LATE THIS EVENING AS THE REGION REMAINS IN THE WARM SECTOR AHEAD OF THE TROUGH. THE BEST FORCING OVERNIGHT...AND MAIN THREAT FOR FZDZ...WILL BE OVER THE NRN WIS/EC MN AREAS WHERE H70-H85 OMEGA AND UPPER LVL JET DIVERGENCE WILL BE GREATEST. THERE IS HIGHER UNCERTAINTY IN THE PROBABILITY OF FZDZ OVER THE MN ZONES TONIGHT AS DRIER AIR RETURNS ONCE THE TROUGH PASSES. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 400 AM CST SUN NOV 24 2013 THE UPPER PATTERN WILL START OUT WITH A RIDGE EXTENDING ALONG THE WESTERN CONUS COAST INTO BC...WITH A TROUGH COVER MUCH OF THE CENTRAL CONUS. THE NORTHLAND WILL BE IN NORTHWEST FLOW ALOFT. THE PATTERN WILL CHANGE LATE IN THE PERIOD AS AN UPPER LOW SETTLES IN JUST OFF THE SOUTHWEST CALIFORNIA COAST BY SATURDAY. OUR FLOW WILL TURN MORE WNW. SEVERAL SHORTWAVES WILL BE MOVING THROUGH THE NORTHWEST FLOW BRINGING A PERIOD OR TWO OF LIGHT SNOW/FLURRIES TO THE NORTHLAND. A SIGNIFICANT LAKE EFFECT SNOW EVENT WILL BE POSSIBLE TUESDAY INTO WEDNESDAY ALONG PORTIONS OF THE SOUTH SHORE. TIMING DIFFERENCES AMONG THE MODELS SHOW UP EARLY IN THE PERIOD...WITH THE GFS A BIT FASTER WITH A SHORTWAVE MONDAY NIGHT AND TUESDAY AS WELL BEING FASTER PUSHING AN AREA OF HIGH PRESSURE THROUGH THE AREA TUESDAY NIGHT/WEDNESDAY. WE FOLLOWED CLOSER TO A BLEND OF THE ECMWF/NAM/GEM ON TIMING THESE FEATURES WHICH WERE ALL SLOWER THAN THE GFS. SNOW SHOWERS WILL BE POSSIBLE MONDAY NIGHT AS THE SHORTWAVE MOVES THROUGH AND ANOTHER SHOT OF COLDER AIR PUSHES THROUGH. SNOW ACCUMULATIONS WILL BE LIGHT...WITH SOME AREAS PERHAPS GETTING AROUND AN INCH...MAINLY FAR NORTH. LOW LEVEL WINDS LOOK TOO WEST OF NORTH MONDAY NIGHT FOR LAKE EFFECT SNOW DESPITE THE COLD AIR...-15C TO -17C OVER LAKE SUPERIOR AT 850MB. EMPHASIS WILL SHIFT TO LAKE EFFECT SNOW ALONG THE SNOWBELT REGION OF ASHLAND/IRON COUNTIES TUESDAY INTO WEDNESDAY AS LITTLE SNOW WILL FALL OUTSIDE OF THIS AREA. WINDS VEER TO NORTHERLY TUESDAY WITH 850MB TEMPS AROUND -18C TO -20C. A LONG FETCH/LOW STABILITY/INVERSION HEIGHTS WILL BE QUITE FAVORABLE FOR LES. MOISTURE DEPTH ALSO LOOKS BETTER WITH THIS EVENT VERSUS THE RECENT LES FRIDAY NIGHT/SATURDAY. THE LOW LEVEL WINDS ARE FORECAST TO VEER TO MORE NORTHEAST TUESDAY NIGHT AND CONTINUE TO BE NNE ON WEDNESDAY. THIS SHOULD SHIFT THE SNOW BANDS FURTHER WEST MORE INTO NORTHWEST IRON INTO ASHLAND COUNTIES. CONDITIONS WILL GRADUALLY BECOME LESS FAVORABLE FOR LES LATE TUESDAY NIGHT INTO WEDNESDAY AS BOTH THE NAM AND ECMWF SHOW DRIER AIR MOVING OVER LAKE SUPERIOR ALONG WITH A RIDGE OF HIGH PRESSURE. THE FETCH WILL BE MORE FAVORABLE THOUGH WITH LONGER RESIDENCE TIME OVER THE LAKE. THE TUESDAY-WEDNESDAY MORNING PERIOD BEARS A CLOSE WATCH AS A HEADLINE FOR SIGNIFICANT SNOW WILL LIKELY BE NEEDED IF THESE FORECAST CONDITIONS CONTINUE. A SHORTWAVE WEDNESDAY NIGHT/THURSDAY MAY BRING SOME LIGHT SNOW TO NORTHERN PORTIONS OF THE REGION...WITH A BRIEF PERIOD OF LAKE ENHANCED SNOW POSSIBLE ALONG COASTAL COOK COUNTY. ANOTHER SYSTEM LATE IN THE PERIOD WILL BRING A CHANCE FOR SNOW...BUT SIGNIFICANT SNOWFALL LOOKS UNLIKELY AT THIS POINT OUTSIDE OF THE LES CHANCES MENTIONED ABOVE. EXPECT HIGH TEMPERATURES TUESDAY TO BE IN THE TEENS TO AROUND 20 WITH THEM ONLY MODERATING SLIGHTLY THROUGH THE PERIOD TO 25 TO 30 BY NEXT SATURDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 540 AM CST SUN NOV 24 2013 STRONG WAA OVER THE NORTHLAND WILL CAUSE MID-HIGH LEVEL CLOUDS TO MOVE THROUGH THE AREA TODAY...WITH A CHANCE FOR LIGHT SNOW AND LOWER CEILINGS ACROSS NORTHERN MINNESOTA. A COLD FRONT WILL THEN MOVE INTO THE AREA TONIGHT. SOUNDINGS SUGGEST IF SOME PRECIPITATION DOES OCCUR TONIGHT...FREEZING DRIZZLE WILL BE POSSIBLE. AT THIS TIME...CONFIDENCE IN PRECIP COVERAGE IS LOW AND WE MENTION SOME LIGHT SNOW THIS MORNING AT KINL...AND SOME FZDZ AT KHIB/KDLH/KHYR LATER TONIGHT. KHYR HAS THE BEST CHANCE AT SEEING THE FZDZ. CEILINGS TONIGHT WILL ALSO BE A QUESTION MARK...WITH THE RAP/NAM SHOWING LOWER CEILINGS MOVING IN OR DEVELOPING. THE RAP HAS SLOWED THE MOVEMENT OF LOWER CEILINGS ACROSS THE FAR NORTH WITH IT`S MOST RECENT UPDATE. WE FEEL MOST CONFIDENT KINL AND KHYR WILL HAVE MVFR CEILINGS. && .PRELIMINARY POINT TEMPS/POPS... DLH 26 20 31 11 / 10 20 10 20 INL 26 20 25 8 / 20 20 30 40 BRD 27 24 31 12 / 0 10 10 20 HYR 24 20 33 16 / 10 20 20 20 ASX 27 23 34 17 / 10 20 20 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 AM CST WEDNESDAY FOR LSZ121-146>148. SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 PM CST MONDAY FOR LSZ140>145. && $$ UPDATE...GSF SHORT TERM...GRANING LONG TERM...MELDE AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
547 AM CST SUN NOV 24 2013 .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 400 AM CST SUN NOV 24 2013 A STRONG PUSH OF WARM AIR ADVECTION WILL OVERTAKE THE REGION TODAY AS A LOW LEVEL TROUGH SWEEPS ACROSS THE DAKOTAS. LATEST MODELS IN GOOD AGREEMENT THAT H85 TEMPS INCREASE ON THE ODER OF >10 C THROUGH THE DAY AS A LOW LEVEL JET STREAK OF 40-50 KT WRLY WINDS ADVECT ACROSS CENTRAL MN. AFTERNOON TEMPERATURES WILL RETURN TO MORE SEASONAL VALUES TODAY...IN THE MID TO UPPER 20S. A FAST MOVING VORT MAX WILL SLIDE ALONG THE INTERNATIONAL BORDER THIS MORNING...REACHING THE MN ARROWHEAD ZONES THIS AFTERNOON. THE COMBINATION OF MID LEVEL OMEGA IN THE DENDRITIC GROWTH ZONE...AND LAKE EFFECT/ENHANCEMENT FROM THE STRONG S/SW BOUNDARY LAYER WINDS WILL PRODUCE A QUICK INCH OR SO ALONG THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE MAIN CORRIDOR OF SNOW ACCUMULATION WILL BE ALONG HIGHWAY 61 FROM SILVER BAY...TO LUTSEN...GRAND MARAIS AND GRAND PORTAGE. LOCATIONS IN THE ELEVATED TERRAIN OF COOK COUNTY...A FEW MILES INLAND FROM LAKE SUPERIOR...CAN EXPECT LOCALLY HIGHER AMOUNTS AROUND 2 INCHES DUE TO ENHANCED OROGRAPHIC LIFT. FOCUS TURNS TO THREAT FOR FREEZING DRIZZLE OVERNIGHT AHEAD OF FRONTAL PASSAGE. LATEST NAM BUFR SOUNDINGS ACROSS MUCH THE NORTHLAND SHOW PROFILES WITH A DEEP SATURATED LAYER...AND CLOUD TOP TEMPERATURES IN THE SINGLE DIGITS BELOW ZERO LATE THIS EVENING AS THE REGION REMAINS IN THE WARM SECTOR AHEAD OF THE TROUGH. THE BEST FORCING OVERNIGHT...AND MAIN THREAT FOR FZDZ...WILL BE OVER THE NRN WIS/EC MN AREAS WHERE H70-H85 OMEGA AND UPPER LVL JET DIVERGENCE WILL BE GREATEST. THERE IS HIGHER UNCERTAINTY IN THE PROBABILITY OF FZDZ OVER THE MN ZONES TONIGHT AS DRIER AIR RETURNS ONCE THE TROUGH PASSES. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 400 AM CST SUN NOV 24 2013 THE UPPER PATTERN WILL START OUT WITH A RIDGE EXTENDING ALONG THE WESTERN CONUS COAST INTO BC...WITH A TROUGH COVER MUCH OF THE CENTRAL CONUS. THE NORTHLAND WILL BE IN NORTHWEST FLOW ALOFT. THE PATTERN WILL CHANGE LATE IN THE PERIOD AS AN UPPER LOW SETTLES IN JUST OFF THE SOUTHWEST CALIFORNIA COAST BY SATURDAY. OUR FLOW WILL TURN MORE WNW. SEVERAL SHORTWAVES WILL BE MOVING THROUGH THE NORTHWEST FLOW BRINGING A PERIOD OR TWO OF LIGHT SNOW/FLURRIES TO THE NORTHLAND. A SIGNIFICANT LAKE EFFECT SNOW EVENT WILL BE POSSIBLE TUESDAY INTO WEDNESDAY ALONG PORTIONS OF THE SOUTH SHORE. TIMING DIFFERENCES AMONG THE MODELS SHOW UP EARLY IN THE PERIOD...WITH THE GFS A BIT FASTER WITH A SHORTWAVE MONDAY NIGHT AND TUESDAY AS WELL BEING FASTER PUSHING AN AREA OF HIGH PRESSURE THROUGH THE AREA TUESDAY NIGHT/WEDNESDAY. WE FOLLOWED CLOSER TO A BLEND OF THE ECMWF/NAM/GEM ON TIMING THESE FEATURES WHICH WERE ALL SLOWER THAN THE GFS. SNOW SHOWERS WILL BE POSSIBLE MONDAY NIGHT AS THE SHORTWAVE MOVES THROUGH AND ANOTHER SHOT OF COLDER AIR PUSHES THROUGH. SNOW ACCUMULATIONS WILL BE LIGHT...WITH SOME AREAS PERHAPS GETTING AROUND AN INCH...MAINLY FAR NORTH. LOW LEVEL WINDS LOOK TOO WEST OF NORTH MONDAY NIGHT FOR LAKE EFFECT SNOW DESPITE THE COLD AIR...-15C TO -17C OVER LAKE SUPERIOR AT 850MB. EMPHASIS WILL SHIFT TO LAKE EFFECT SNOW ALONG THE SNOWBELT REGION OF ASHLAND/IRON COUNTIES TUESDAY INTO WEDNESDAY AS LITTLE SNOW WILL FALL OUTSIDE OF THIS AREA. WINDS VEER TO NORTHERLY TUESDAY WITH 850MB TEMPS AROUND -18C TO -20C. A LONG FETCH/LOW STABILITY/INVERSION HEIGHTS WILL BE QUITE FAVORABLE FOR LES. MOISTURE DEPTH ALSO LOOKS BETTER WITH THIS EVENT VERSUS THE RECENT LES FRIDAY NIGHT/SATURDAY. THE LOW LEVEL WINDS ARE FORECAST TO VEER TO MORE NORTHEAST TUESDAY NIGHT AND CONTINUE TO BE NNE ON WEDNESDAY. THIS SHOULD SHIFT THE SNOWBANDS FURTHER WEST MORE INTO NORTHWEST IRON INTO ASHLAND COUNTIES. CONDITIONS WILL GRADUALLY BECOME LESS FAVORABLE FOR LES LATE TUESDAY NIGHT INTO WEDNESDAY AS BOTH THE NAM AND ECMWF SHOW DRIER AIR MOVING OVER LAKE SUPERIOR ALONG WITH A RIDGE OF HIGH PRESSURE. THE FETCH WILL BE MORE FAVORABLE THOUGH WITH LONGER RESIDENCE TIME OVER THE LAKE. THE TUESDAY-WEDNESDAY MORNING PERIOD BEARS A CLOSE WATCH AS A HEADLINE FOR SIGNIFICANT SNOW WILL LIKELY BE NEEDED IF THESE FORECAST CONDITIONS CONTINUE. A SHORTWAVE WEDNESDAY NIGHT/THURSDAY MAY BRING SOME LIGHT SNOW TO NORTHERN PORTIONS OF THE REGION...WITH A BRIEF PERIOD OF LAKE ENHANCED SNOW POSSIBLE ALONG COASTAL COOK COUNTY. ANOTHER SYSTEM LATE IN THE PERIOD WILL BRING A CHANCE FOR SNOW...BUT SIGNIFICANT SNOWFALL LOOKS UNLIKELY AT THIS POINT OUTSIDE OF THE LES CHANCES MENTIONED ABOVE. EXPECT HIGH TEMPERATURES TUESDAY TO BE IN THE TEENS TO AROUND 20 WITH THEM ONLY MODERATING SLIGHTLY THROUGH THE PERIOD TO 25 TO 30 BY NEXT SATURDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 540 AM CST SUN NOV 24 2013 STRONG WAA OVER THE NORTHLAND WILL CAUSE MID-HIGH LEVEL CLOUDS TO MOVE THROUGH THE AREA TODAY...WITH A CHANCE FOR LIGHT SNOW AND LOWER CEILINGS ACROSS NORTHERN MINNESOTA. A COLD FRONT WILL THEN MOVE INTO THE AREA TONIGHT. SOUNDINGS SUGGEST IF SOME PRECIPITATION DOES OCCURN TONIGHT...FREEZING DRIZZLE WILL BE POSSIBLE. AT THIS TIME...CONFIDENCE IN PRECIP COVERAGE IS LOW AND WE MENTION SOME LIGHT SNOW THIS MORNING AT KINL...AND SOME FZDZ AT KHIB/KDLH/KHYR LATER TONIGHT. KHYR HAS THE BEST CHANCE AT SEEING THE FZDZ. CEILINGS TONIGHT WILL ALSO BE A QUESTION MARK...WITH THE RAP/NAM SHOWING LOWER CEILINGS MOVING IN OR DEVELOPING. THE RAP HAS SLOWED THE MOVEMENT OF LOWER CEILINGS ACROSS THE FAR NORTH WITH IT`S MOST RECENT UPDATE. WE FEEL MOST CONFIDENT KINL AND KHYR WILL HAVE MVFR CEILINGS. && .PRELIMINARY POINT TEMPS/POPS... DLH 26 20 31 11 / 10 20 10 20 INL 26 20 25 8 / 20 20 30 40 BRD 27 24 31 12 / 0 10 10 20 HYR 24 20 33 16 / 10 20 20 20 ASX 27 23 34 17 / 10 20 20 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 AM CST WEDNESDAY FOR LSZ121-146>148. SMALL CRAFT ADVISORY FROM NOON TODAY TO 4 PM CST MONDAY FOR LSZ140>145. && $$ SHORT TERM...GRANING LONG TERM...MELDE AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
236 PM CST SUN NOV 24 2013 .SYNOPSIS... ISSUED AT 235 PM CST SUN NOV 24 2013 AN UPPER LOW SPUN OVER THE FOUR CORNERS ON SUNDAY AFTERNOON...WHICH PUSHED SOME MID AND HIGH LEVEL CLOUDS INTO SOUTHERN NEBRASKA. WITH THE UPPER LOW TO THE SOUTH...WESTERLY FLOW ALOFT HAS ALLOWED FOR A THERMAL RIDGE TO MOVE INTO THE NORTHERN PLAINS TODAY WHERE 850MB TEMPERATURES WERE GENERALLY 5C TO 10C AS OF 12Z THIS MORNING COMPARED TO 0C TO-5C ACROSS NEBRASKA. LOOKING AT WATER VAPOR...COULD MAKE OUT THE NEXT LOW PRESSURE SYSTEM IN LINE IN THE NORTHWEST FLOW OVER SASKATCHEWAN...WITH ANOTHER BATCH OF COLD ARCTIC AIR BEHIND IT. && .SHORT TERM...(THIS AFTERNOON THROUGH MONDAY) ISSUED AT 235 PM CST SUN NOV 24 2013 THE UPPER LEVEL LOW OVER THE FOUR CORNERS IS EXPECTED TO START GETTING INFLUENCED BY THE MEAN NORTHWEST FLOW AND START TO PUSH INTO TEXAS BY THE END OF THE DAY MONDAY. THIS SHOULD ALLOW FOR THE MID AND HIGH CLOUDS THAT HAVE BEEN SPINNING AROUND THIS SYSTEM INTO THE SOUTHERN PART OF THE FORECAST AREA FOR THE PAST SEVERAL DAYS TO GET PULLED SOUTHWARD AND AWAY FROM THE LOCAL AREA TONIGHT AND MONDAY MORNING. IT WILL ALSO ALLOW FOR SOME OF THE COLDER AIR ASSOCIATED WITH THAT SYSTEM TO GET PUSHED AWAY FROM THE AREA. MEANWHILE...THE LOW PRESSURE SYSTEM OVER SASKATCHEWAN WILL MOVE INTO ONTARIO WHICH WILL DRAG A COLD FRONT ACROSS NEBRASKA TONIGHT AND MONDAY MORNING. ALTHOUGH TEMPERATURES BEHIND THE FRONT WON/T BE MUCH COLDER FOR THE LOCAL AREA. WINDS WILL SWITCH TO THE NORTH-NORTHWEST BEHIND THE FRONT. FORECAST SOUNDINGS ARE SHOWING MINIMAL MIXING MONDAY AFTERNOON...BUT WINDS JUST ABOVE THE SURFACE ARE ABOUT 25KTS SO COULD SEE SOME 20KT WINDS AT GROUND LEVEL DURING THE AFTERNOON. ONE CONCERN WITH THE FORECAST WILL BE THE POTENTIAL FOR THE DEVELOPMENT OF SHALLOW STRATUS THIS EVENING AND TONIGHT FROM SOUTHWEST INTO CENTRAL NEBRASKA. LOW LEVEL MOISTURE ADVECTION IS BEING INDICATED INTO THE AREA AHEAD OF THE FRONT BY SEVERAL FORECAST MODELS...WITH THE NAM BEING THE MOST ROBUST SPREADING STRATUS ACROSS THE ENTIRE FORECAST AREA. DISCOUNTING THAT MODEL AND LOOKING CLOSER TO THE RAP WHICH HAS BEEN HOLDING OFF THE LOW LEVEL MOISTURE FROM MOVING INTO NEBRASKA THROUGH THE DAY TODAY. ALTHOUGH IT HAS KEPT THIS MOISTURE SOUTH TODAY...IT DOES CONTINUE TO PUSH IT INTO NEBRASKA THIS EVENING...WITH CLOUDS REMAINING UNTIL THE FRONT PUSHES THROUGH LATE TONIGHT AND MONDAY MORNING. WATCHING THE STRATUS STRUGGLE TO DEVELOP IN UPSTREAM AREAS TODAY...AND WITH THE RAP CONTINUOUSLY BACKING OFF ON THE TIMING OF BRINGING IT NORTH...JUST DON/T HAVE THE CONFIDENCE THAT THE CLOUDS WILL GET INTO THE LOCAL AREA TONIGHT AND THE FORECAST TAKES THAT INTO ACCOUNT. IF THE STRATUS DOES MOVE IN...MAY HAVE TO TAKE A LOOK AT LOW TEMPERATURES TONIGHT...ALTHOUGH THEY SHOULDN/T HAVE AN IMPACT ON HIGHS MONDAY AS THEY WOULD BE PUSHED OUT OF THE AREA BEFORE PEAK HEATING. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 235 PM CST SUN NOV 24 2013 A REINFORCING SHOT OF ARCTIC AIR WILL MOVE THROUGH THE DAKOTAS INTO NEBRASKA MONDAY NIGHT AND TUESDAY. THIS WILL BRING A GLANCING BLOW OF COLDER AIR...WHICH IS ACTUALLY NOT AS COLD AS THE PREVIOUS ONE SATURDAY. WENT A FEW DEGREES ABOVE GUIDANCE LOWS MONDAY NIGHT WITH MID/UPPER TEENS. WEAK COLD AIR ADVECTION TUESDAY WITH H85 TEMPS AS LOW AS -15C PER NAM MODEL. THIS LOOK TOO COLD AND FAVORED THE GFS -11C. USING CONSALL INTO A BLEND HIGHS NEAR 25 AT ONL TO 36 AT IML. TEMPERATURES THEN WARMUP FOR WEDNESDAY. AS SURFACE HIGH SLIDES EAST...A RETURN SOUTH TO SOUTHWEST FLOW DEVELOPS. WHILE HIGHS TO BE LIMITED TO NEAR 30 AT BBW AND ONL...THE WESTERN TIER OF COUNTIES TO WARM TO 40-43 DEGREES. DRY CONDITIONS TO ALSO PREVAIL. FOR THANKSGIVING DAY THROUGH THE WEEKEND...DRY AND SEASONAL TEMPERATURES ARE FORECAST. THE UPPER FLOW WILL REMAIN FAIRLY ZONAL. THIS HIGHLIGHTED BY AN UPPER TROUGH DIGGING FROM BRITISH COLUMBIA INTO THE NORTHERN PLAINS AND A CLOSED LOW REMAINING OFF THE CALIF. COAST. ONLY A WEAK COLD FRONT INDICATED FRIDAY NIGHT...WHICH SHOULD HAVE MINIMAL IMPACT TO HIGHS SATURDAY AND SUNDAY. ONLY VERY MINOR CHANGES TO HIGHS THROUGH THIS WEEKEND WITH MAINLY UPPER 30S TO MID 40S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1225 PM CST SUN NOV 24 2013 WINDS WILL BE BREEZY FROM THE SOUTH-SOUTHWEST THROUGH THE AFTERNOON. WINDS WILL DIMINISH BY 00Z...THEN WILL SWITCH TO THE NORTHWEST OVERNIGHT AS A WEAK FRONT MOVES ACROSS WESTERN NEBRASKA. LOOK FOR THE WINDS TO INCREASE THEN BY LATE MONDAY MORNING...WHERE GUSTS COULD REACH 20KTS INTO THE AFTERNOON. THERE CONTINUES TO BE INDICATION OF STRATUS DEVELOPMENT INTO SOUTHWEST NEBRASKA TONIGHT /PRIMARILY IMPACTING KLBF/ AS MODELS ARE SHOWING A SHALLOW LAYER OF MOISTURE IN THE BOUNDARY LAYER MOVING INTO THE AREA. THE MODELS HAVE BEEN HAVING SOME PROBLEMS HANDLING THIS LOW LEVEL MOISTURE OVER THE LAST SEVERAL DAYS SO DON/T HAVE MUCH CONFIDENCE IN THAT SOLUTION AND LEFT THE MVFR CEILINGS OUT OF THE FORECAST FOR NOW. WILL KEEP A WATCH ON THIS THROUGH THE AFTERNOON. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BROOKS SHORT TERM...BROOKS LONG TERM...ROBERG AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1225 PM CST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 323 AM CST SUN NOV 24 2013 1045 MB ARCTIC HIGH PRESSURE CENTERED NEAR KANSAS CITY WILL MOVE RAPIDLY EAST THROUGH THE MIDSOUTH TODAY AND BE LOCATED OVER NORTH CAROLINA BY MONDAY MORNING. THE MODELS INSIST STRATUS WILL FORM IN THE RETURN FLOW SETTING ACROSS SWRN NEB. AT 08Z THE NEAREST STRATUS WAS OVER NW TEX...ABOUT 500 MILES SOUTH OF THE FORECAST POSITION OF THE MODEL CONSENSUS. NO STRATUS IS EXPECTED TO DEVELOP AT THIS TIME BUT MID LEVEL CLOUDS ACROSS ERN COLO/WRN KS ARE EXPECTED TO LIFT NORTH PART WAY THROUGH THE FCST AREA AND THEN GET SHUNTED EAST WITH THE APPROACH OF A NRN STREAM SHORTWAVE THIS EVENING. TEMPERATURES ARE EXPECTED TO RISE INTO THE 30S TO AROUND 40. WARMER GUIDANCE WAS USED FOR THE FORECAST OWING TO THE CONTAMINATION IN THE SKY COVER SHOWN BY MOST MODELS. FOR TONIGHT A COLD FRONT WILL BE MOVING SOUTH THROUGH THE NRN HIGH PLAINS. A THERMAL RIDGE WILL BE RUNNING OUT AHEAD OF THE COLD FRONT WHICH WILL LIKELY PRODUCE THE COOLEST LOWS IN THE SOUTH BEFORE THE WIND SHIFT DEVELOPS LATE TONIGHT. THUS LOWS IN THE TEENS ARE EXPECTED SOUTH WITH 20S NORTH. SOUTH AND SOUTHWEST WINDS TODAY INCREASE TO 15 TO 25 MPH. LOW PRESSURE CURRENTLY ACROSS GREAT SLAVE LAKE WILL DIVE SOUTHEAST TOWARD LAKE SUPERIOR TODAY AND TONIGHT. THE 500M AGL WINDS IN THE NAM AND RAP MODELS INCREASE TO NEAR 30 MPH AT THE SFC EAST OF HIGHWAY 183. THIS WOULD SUPPORT GUSTS TO 35 MPH BUT LIMITED VERTICAL MIXING IN COOL RETURN FLOW SHOULD LIMIT SUSTAINED WIND SPEEDS TO 25 MPH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 323 AM CST SUN NOV 24 2013 A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MIGRATE FROM ARIZONA TO WEST TEXAS BY MONDAY. MEANWHILE ANOTHER POTENT SHORTWAVE TROUGH WILL DIVE SOUTHEAST THROUGH CENTRAL CANADA...REACHING THE GREAT LAKES BY TUESDAY EVENING. THE SOUTHERN PLAINS LOW AND GREAT LAKES TROUGH WILL EVENTUALLY PHASE TO OUR EAST...AND BRING HEAVY PRECIPITATION ALONG THE EAST COAST WEDNESDAY AND WEDNESDAY NIGHT. AS MENTIONED...THE MAJORITY OF THE WEATHER WITH THESE SYSTEMS REMAINS TO OUR EAST...BUT A COLD FRONT WILL DROP SOUTH THROUGH THE AREA TUESDAY. THIS WILL BRING ANOTHER REINFORCING SHOT OF ARCTIC AIR TO THE REGION. THE BRUNT OF THE ARCTIC AIR WILL BE FELT ACROSS THE MISSOURI RIVER VALLEY...WHERE HIGHS IN THE 20S ARE EXPECTED. FARTHER WEST ACROSS THE HIGH PLAINS OF WESTERN NEBRASKA AND EASTERN COLORADO...THE COLD FRONT WILL HAVE LITTLE IMPACT...WITH A PACIFIC AIRMASS AND HIGHS IN THE 40S REMAINING IN PLACE. BY MID TO LATE WEEK...UPPER LEVEL RIDGING WILL BUILD EAST ACROSS THE CENTRAL CONUS. WARMER PACIFIC AIR WILL ALSO SPREAD EAST...WITH HIGHS IN THE UPPER 30S TO MID 40S REGION WIDE. LITTLE PRECIPITATION IS EXPECTED...AS ATMOSPHERIC MOISTURE REMAINS LIMITED THROUGH THE END OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1225 PM CST SUN NOV 24 2013 WINDS WILL BE BREEZY FROM THE SOUTH-SOUTHWEST THROUGH THE AFTERNOON. WINDS WILL DIMINISH BY 00Z...THEN WILL SWITCH TO THE NORTHWEST OVERNIGHT AS A WEAK FRONT MOVES ACROSS WESTERN NEBRASKA. LOOK FOR THE WINDS TO INCREASE THEN BY LATE MONDAY MORNING...WHERE GUSTS COULD REACH 20KTS INTO THE AFTERNOON. THERE CONTINUES TO BE INDICATION OF STRATUS DEVELOPMENT INTO SOUTHWEST NEBRASKA TONIGHT /PRIMARILY IMPACTING KLBF/ AS MODELS ARE SHOWING A SHALLOW LAYER OF MOISTURE IN THE BOUNDARY LAYER MOVING INTO THE AREA. THE MODELS HAVE BEEN HAVING SOME PROBLEMS HANDLING THIS LOW LEVEL MOISTURE OVER THE LAST SEVERAL DAYS SO DON/T HAVE MUCH CONFIDENCE IN THAT SOLUTION AND LEFT THE MVFR CEILINGS OUT OF THE FORECAST FOR NOW. WILL KEEP A WATCH ON THIS THROUGH THE AFTERNOON. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
524 AM CST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 323 AM CST SUN NOV 24 2013 1045 MB ARCTIC HIGH PRESSURE CENTERED NEAR KANSAS CITY WILL MOVE RAPIDLY EAST THROUGH THE MIDSOUTH TODAY AND BE LOCATED OVER NORTH CAROLINA BY MONDAY MORNING. THE MODELS INSIST STRATUS WILL FORM IN THE RETURN FLOW SETTING ACROSS SWRN NEB. AT 08Z THE NEAREST STRATUS WAS OVER NW TEX...ABOUT 500 MILES SOUTH OF THE FORECAST POSITION OF THE MODEL CONSENSUS. NO STRATUS IS EXPECTED TO DEVELOP AT THIS TIME BUT MID LEVEL CLOUDS ACROSS ERN COLO/WRN KS ARE EXPECTED TO LIFT NORTH PART WAY THROUGH THE FCST AREA AND THEN GET SHUNTED EAST WITH THE APPROACH OF A NRN STREAM SHORTWAVE THIS EVENING. TEMPERATURES ARE EXPECTED TO RISE INTO THE 30S TO AROUND 40. WARMER GUIDANCE WAS USED FOR THE FORECAST OWING TO THE CONTAMINATION IN THE SKY COVER SHOWN BY MOST MODELS. FOR TONIGHT A COLD FRONT WILL BE MOVING SOUTH THROUGH THE NRN HIGH PLAINS. A THERMAL RIDGE WILL BE RUNNING OUT AHEAD OF THE COLD FRONT WHICH WILL LIKELY PRODUCE THE COOLEST LOWS IN THE SOUTH BEFORE THE WIND SHIFT DEVELOPS LATE TONIGHT. THUS LOWS IN THE TEENS ARE EXPECTED SOUTH WITH 20S NORTH. SOUTH AND SOUTHWEST WINDS TODAY INCREASE TO 15 TO 25 MPH. LOW PRESSURE CURRENTLY ACROSS GREAT SLAVE LAKE WILL DIVE SOUTHEAST TOWARD LAKE SUPERIOR TODAY AND TONIGHT. THE 500M AGL WINDS IN THE NAM AND RAP MODELS INCREASE TO NEAR 30 MPH AT THE SFC EAST OF HIGHWAY 183. THIS WOULD SUPPORT GUSTS TO 35 MPH BUT LIMITED VERTICAL MIXING IN COOL RETURN FLOW SHOULD LIMIT SUSTAINED WIND SPEEDS TO 25 MPH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 323 AM CST SUN NOV 24 2013 A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MIGRATE FROM ARIZONA TO WEST TEXAS BY MONDAY. MEANWHILE ANOTHER POTENT SHORTWAVE TROUGH WILL DIVE SOUTHEAST THROUGH CENTRAL CANADA...REACHING THE GREAT LAKES BY TUESDAY EVENING. THE SOUTHERN PLAINS LOW AND GREAT LAKES TROUGH WILL EVENTUALLY PHASE TO OUR EAST...AND BRING HEAVY PRECIPITATION ALONG THE EAST COAST WEDNESDAY AND WEDNESDAY NIGHT. AS MENTIONED...THE MAJORITY OF THE WEATHER WITH THESE SYSTEMS REMAINS TO OUR EAST...BUT A COLD FRONT WILL DROP SOUTH THROUGH THE AREA TUESDAY. THIS WILL BRING ANOTHER REINFORCING SHOT OF ARCTIC AIR TO THE REGION. THE BRUNT OF THE ARCTIC AIR WILL BE FELT ACROSS THE MISSOURI RIVER VALLEY...WHERE HIGHS IN THE 20S ARE EXPECTED. FARTHER WEST ACROSS THE HIGH PLAINS OF WESTERN NEBRASKA AND EASTERN COLORADO...THE COLD FRONT WILL HAVE LITTLE IMPACT...WITH A PACIFIC AIRMASS AND HIGHS IN THE 40S REMAINING IN PLACE. BY MID TO LATE WEEK...UPPER LEVEL RIDGING WILL BUILD EAST ACROSS THE CENTRAL CONUS. WARMER PACIFIC AIR WILL ALSO SPREAD EAST...WITH HIGHS IN THE UPPER 30S TO MID 40S REGION WIDE. LITTLE PRECIPITATION IS EXPECTED...AS ATMOSPHERIC MOISTURE REMAINS LIMITED THROUGH THE END OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 523 AM CST SUN NOV 24 2013 VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. MIDLEVEL CLOUD SHIELD ACROSS NERN COLO/SWRN NEB/NWRN KS WILL MOVE NORTH TO NEAR KTIF AND THEN GET SHUNTED EAST AS AN UPPER LEVEL DISTURBANCE...CURRENTLY NEAR GREAT SLAVE LAKE...DROPS SOUTH INTO SRN CANADA. A COLD FRONT WILL MOVE THROUGH THE FCST AREA TONIGHT PRODUCING A WIND SHIFT WITH NW WINDS DEVELOPING. NOTE THE MODELS DEVELOP LOW CLOUDS/MVFR CIGS THIS MORNING ACROSS SRN NEB AND EXPAND THESE CLOUDS NORTH TONIGHT BUT THIS FCST HAS NOT VERIFIED SINCE 00Z LAST NIGHT SO WE ARE SETTING THAT FCST ASIDE AND WAITING ON SFC OBS TO SHOW THIS DEVELOPMENT. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
343 AM CST SUN NOV 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 323 AM CST SUN NOV 24 2013 1045 MB ARCTIC HIGH PRESSURE CENTERED NEAR KANSAS CITY WILL MOVE RAPIDLY EAST THROUGH THE MIDSOUTH TODAY AND BE LOCATED OVER NORTH CAROLINA BY MONDAY MORNING. THE MODELS INSIST STRATUS WILL FORM IN THE RETURN FLOW SETTING ACROSS SWRN NEB. AT 08Z THE NEAREST STRATUS WAS OVER NW TEX...ABOUT 500 MILES SOUTH OF THE FORECAST POSITION OF THE MODEL CONSENSUS. NO STRATUS IS EXPECTED TO DEVELOP AT THIS TIME BUT MID LEVEL CLOUDS ACROSS ERN COLO/WRN KS ARE EXPECTED TO LIFT NORTH PART WAY THROUGH THE FCST AREA AND THEN GET SHUNTED EAST WITH THE APPROACH OF A NRN STREAM SHORTWAVE THIS EVENING. TEMPERATURES ARE EXPECTED TO RISE INTO THE 30S TO AROUND 40. WARMER GUIDANCE WAS USED FOR THE FORECAST OWING TO THE CONTAMINATION IN THE SKY COVER SHOWN BY MOST MODELS. FOR TONIGHT A COLD FRONT WILL BE MOVING SOUTH THROUGH THE NRN HIGH PLAINS. A THERMAL RIDGE WILL BE RUNNING OUT AHEAD OF THE COLD FRONT WHICH WILL LIKELY PRODUCE THE COOLEST LOWS IN THE SOUTH BEFORE THE WIND SHIFT DEVELOPS LATE TONIGHT. THUS LOWS IN THE TEENS ARE EXPECTED SOUTH WITH 20S NORTH. SOUTH AND SOUTHWEST WINDS TODAY INCREASE TO 15 TO 25 MPH. LOW PRESSURE CURRENTLY ACROSS GREAT SLAVE LAKE WILL DIVE SOUTHEAST TOWARD LAKE SUPERIOR TODAY AND TONIGHT. THE 500M AGL WINDS IN THE NAM AND RAP MODELS INCREASE TO NEAR 30 MPH AT THE SFC EAST OF HIGHWAY 183. THIS WOULD SUPPORT GUSTS TO 35 MPH BUT LIMITED VERTICAL MIXING IN COOL RETURN FLOW SHOULD LIMIT SUSTAINED WIND SPEEDS TO 25 MPH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 323 AM CST SUN NOV 24 2013 A SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MIGRATE FROM ARIZONA TO WEST TEXAS BY MONDAY. MEANWHILE ANOTHER POTENT SHORTWAVE TROUGH WILL DIVE SOUTHEAST THROUGH CENTRAL CANADA...REACHING THE GREAT LAKES BY TUESDAY EVENING. THE SOUTHERN PLAINS LOW AND GREAT LAKES TROUGH WILL EVENTUALLY PHASE TO OUR EAST...AND BRING HEAVY PRECIPITATION ALONG THE EAST COAST WEDNESDAY AND WEDNESDAY NIGHT. AS MENTIONED...THE MAJORITY OF THE WEATHER WITH THESE SYSTEMS REMAINS TO OUR EAST...BUT A COLD FRONT WILL DROP SOUTH THROUGH THE AREA TUESDAY. THIS WILL BRING ANOTHER REINFORCING SHOT OF ARCTIC AIR TO THE REGION. THE BRUNT OF THE ARCTIC AIR WILL BE FELT ACROSS THE MISSOURI RIVER VALLEY...WHERE HIGHS IN THE 20S ARE EXPECTED. FARTHER WEST ACROSS THE HIGH PLAINS OF WESTERN NEBRASKA AND EASTERN COLORADO...THE COLD FRONT WILL HAVE LITTLE IMPACT...WITH A PACIFIC AIRMASS AND HIGHS IN THE 40S REMAINING IN PLACE. BY MID TO LATE WEEK...UPPER LEVEL RIDGING WILL BUILD EAST ACROSS THE CENTRAL CONUS. WARMER PACIFIC AIR WILL ALSO SPREAD EAST...WITH HIGHS IN THE UPPER 30S TO MID 40S REGION WIDE. LITTLE PRECIPITATION IS EXPECTED...AS ATMOSPHERIC MOISTURE REMAINS LIMITED THROUGH THE END OF THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1147 PM CST SAT NOV 23 2013 UPPER LEVEL LOW PRESSURE WILL TRACK ACROSS THE SOUTHERN ROCKIES INTO THE SOUTHERN PLAINS OVER THE NEXT 24 HOURS. THIS FEATURE WILL SPREAD ABUNDANT HIGH CLOUDS INTO SOUTHERN NEBRASKA TONIGHT...FOLLOWED BY SOME LOW LEVEL CLOUDINESS ON SUNDAY. AT THIS TIME...LOW LEVEL CLOUDINESS WITH CIGS BETWEEN 3000 AND 5000 FT AGL WILL BE POSSIBLE AT THE KLBF TERMINAL SUNDAY MORNING THROUGH SUNDAY EVENING. AT THE KVTN TERMINAL...SKIES WILL BE CLEAR TONIGHT WITH SOME SCATTERED TO BROKEN HIGH CLOUDS AON 25000 FT AGL POSSIBLE AFTER 16Z SUNDAY. WINDS WILL BE FROM THE SOUTH AT 5 TO 10 KTS TONIGHT...INCREASING TO 15 TO 25 KTS SUNDAY...DIMINISHING BACK TO AROUND 10 KTS SUNDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CLB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1105 AM PST SUN NOV 24 2013 .SYNOPSIS...A SLOW MOVING LOW PRESSURE WILL FINALLY PULL AWAY FROM THE AREA TODAY RESULTING IN DRIER CONDITIONS. FURTHER WARMING IS EXPECTED ACROSS THE AREA MONDAY THROUGH WEDNESDAY. ANOTHER AREA OF LOW PRESSURE DROPPING SOUTH NEAR THE CALIFORNIA COAST MAY BRING A FEW SHOWERS MAINLY TO WESTERN PORTIONS OF THE AREA FOR THANKSGIVING DAY AND FRIDAY. && .UPDATE...UPPER LOW EXITING THE REGION TODAY WITH A FEW SHOWERS STILL POSSIBLE IN MOHAVE COUNTY AND FAR EASTERN LINCOLN COUNTY. CLOUDS HAD CLEARED OUT A BIT MORE THAN PREVIOUSLY FORECAST AND THE SKY COVER GRID WAS ADJUSTED TO REDUCE SKY COVER OVER A GOOD PORTION OF THE FORECAST AREA. NO OTHER UPDATES NEEDED. && .AVIATION...FOR MCCARRAN...SOME DRYING OF THE LOWER LEVELS OF THE ATMOSPHERE IS TAKING PLACE...AND THE LOWEST CLOUD BASES HAVE SCATTERED OUT LEAVING CIGS GENERALLY AROUND 10K FEET. CLEARING BEGINS TONIGHT WITH MAINLY CLEAR SKIES EXPECTED MONDAY. WINDS WILL FAVOR MORE TYPICAL DIURNAL TRENDS THROUGH TONIGHT AT SPEEDS MAINLY LESS THAN 6 KTS. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...SHOWERS SHOULD BE CONFINED TO EASTERN MOHAVE COUNTY THROUGH AROUND 21Z. CIGS BTWN 5K-8K FEET IN THIS AREA OTHERWISE SCT-BKN AROUND 10K FEET. WINDS OVERALL SHOULD FAVOR TYPICAL DIURNAL TRENDS AT 10 KTS OR LESS. MAINLY CLEAR CONDITIONS MONDAY EXPECT FOR PATCHY FG/BR POSSIBLE EARLY IN THE MORNING. && .PREV DISCUSSION... 254 AM PST SUN NOV 24 2013 .SHORT TERM...TODAY THROUGH TUESDAY NIGHT. WELL AFTER 3 DAYS OF CLOUDS AND RAIN WE ARE FINALLY IN FOR A CHANGE TODAY IN VEGAS WITH THE POTENTIAL OF SEEING SOME SUNSHINE AS A SLOW MOVING UPPER LEVEL LOW FINALLY HEADS OUT OF THE AREA. THE LATEST WATER VAPOR IMAGERY SHOWS THE CENTER OF THE LOW NEAR PARKER, ARIZONA AS OF EARLY THIS MORNING WITH MOISTURE STILL WRAPPING AROUND THE BACK SIDE OF THE LOW. THE MAIN ISSUE FOR TODAY, ESPECIALLY FOR THIS MORNING, WILL BE HOW QUICKLY WE ARE ABLE TO DRY THINGS OUT ACROSS THE AREA WHICH WILL DETERMINE WHEN SHOWERS COME TO AN END AND HOW QUICKLY ANY LOW AND MID-LEVEL CLOUDS START TO BECOME MORE SCATTERED. THE LATEST RADAR IMAGES FROM KESX SHOW MAINLY LIGHT RETURNS ACROSS THE EASTERN PORTIONS OF THE AREA AND IT IS LIKELY THE RADAR IS OVERSHOOTING SOME OF THE PRECIPITATION. BASED ON THE HRRR AND THE 00Z REGIONAL WRF, THE BEST POTENTIAL FOR ANY SHOWERS THIS MORNING WILL BE ACROSS NORTHERN AND CENTRAL MOHAVE COUNTY, LINCOLN COUNTY AND THE MOUNTAINS OF CLARK COUNTY AND I HAVE KEPT IN 20-30 POPS WITH SOME NEAR 40 POP VALUES (IN THE HIGHEST TERRAIN) OVER THESE AREAS. AS THE LOW LEVELS START TO DRY OUT, WE SHOULD SEE THE LOWER AND MID-LEVEL CLOUDS START TO BECOME MORE SCATTERED IN COVERAGE BY EARLY THIS AFTERNOON ESPECIALLY FROM LINCOLN AND CLARK COUNTIES ON EAST. THERE COULD BE A LITTLE FOG AROUND, MAINLY ALONG THE INTERFACES OF THE HIGHER TERRAIN WHERE THEY HIT THE CLOUD BASES. OUTSIDE OF THE COLORADO CITY AREA WHERE FOG WAS REPORTED EARLIER THIS MORNING, NO OTHER FOG WILL BE PLACED IN THE GRIDS AS THE COVERAGE LOOKS TOO SMALL. WITH THE COLD POOL DEPARTING THE AREA ASSOCIATED WITH THE LOW, A LOT OF WARMING ALOFT WILL TAKE PLACE TODAY. THIS COMBINED WITH SOME SUN WILL MAKE FOR A BIG BOOST IN TEMPS, HOWEVER, HIGHS SHOULD STILL BE ABOUT 10 DEGREES BELOW NORMAL ACROSS THE AREA AND I DID CHOP A FEW DEGREES OFF THE PREVIOUS FORECAST BASED ON THE LATEST GUIDANCE. FOR TONIGHT, SOME LOW AND MID-LEVEL CLOUDS MAY LINGER EARLY ON, OTHERWISE EXPECT A CLEAR SKY. TEMPS SHOULD BE A LITTLE COLDER WITH LESS CLOUD COVER. ONE CONCERN WILL BE IN THE WESTERN PORTIONS OF THE MOJAVE DESERT, MAINLY ACROSS NW SAN BERNARDINO COUNTY AND FAR SW INYO COUNTY, WHERE PATCHY FOG MAY BE POSSIBLE. STATISTICAL GUIDANCE SHOWS NEARLY SATURATED OR SATURATED SFC CONDITIONS TONIGHT (ESPECIALLY THE COLDER MET GUIDANCE) AND BUFKIT SOUNDINGS FROM THE NAM SHOW THE VERY LOW-LEVELS MOISTENING AROUND OR JUST AFTER SUNRISE. I WILL GO AHEAD AND ADD PATCHY FOG IN HERE GIVEN THE WET GROUND FROM THE RECENT RAINS, LIGHT WINDS AND CLEAR SKY EXPECTED INITIALLY TONIGHT, HOWEVER CONFIDENCE IS NOT THE BEST WITH THIS. RIDGING ALOFT IS FORECAST TO SLIDE EAST ACROSS THE AREA FROM MONDAY INTO TUESDAY. THIS WILL RESULT IN FURTHER WARMING WITH HIGHS ABOUT 4-6 DEGREES BELOW NORMAL. AS THE RIDGE AXIS SLIDES EAST ON TUESDAY AND A TROUGH OFFSHORE STARTS TO APPROACH HIGH LEVEL MOISTURE SHOULD START TO SPILL IN FROM THE WEST AND COULD BRING A DECENT AMOUNT OF CIRRUS TO THE AREA FOR TUESDAY NIGHT. .LONG TERM...WEDNESDAY THROUGH SATURDAY...THE PACIFIC SYSTEM THAT IS FORECAST TO APPROACH THE WEST COAST BY LATE WEDNESDAY DOES NOT APPEAR TO HAVE THE MAKINGS OF A SIGNIFICANT STORM FOR OUR FORECAST AREA. THE LATEST MEDIUM RANGE MODELS ARE NOW IN BETTER AGREEMENT WITH THE TRACK OF THE SYSTEM....BRINGING THE CENTER OF THE CLOSED LOW ALONG THE CENTRAL CALIFORNIA COAST THANKSGIVING DAY THEN INDICATING IT WILL TRANSFORM INTO A WEAKER AND ELONGATED POSITIVE TILT TROUGH AS IT SAGS OFF THE SOUTHERN CALIFORNIA COAST FRIDAY AND CONTINUES WORKING TOWARD NORTHERN BAJA SATURDAY. THE BEST CHANCE FOR PRECIPITATION WILL BE ACROSS THE SOUTHERN SIERRA AND THE INYO COUNTY MOUNTAINS THANKSGIVING DAY INTO THURSDAY NIGHT AS A SHORTWAVE EJECTS OUT OF THE COASTAL LOW ACROSS SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA. SNOW WILL BE LIKELY IN THE HIGH SIERRA WITH LESSER CHANCES FOR LIGHT SNOW SHOWERS ACROSS THE REST OF THE INYO COUNTY MOUNTAINS AND THE MOUNTAINS OF SOUTHERN NEVADA. PRECIPITATION CHANCES THEN DIMINISH CONSIDERABLY FRIDAY INTO SATURDAY. CONSIDERING THE SEED FOR THIS SYSTEM IS CURRENTLY A BARELY NOTICEABLE PACIFIC SHORTWAVE NEAR 40N AND THE DATELINE...THERE ARE SURE TO BE SOME CHANGES DURING ITS EVOLUTION. IT BEARS WATCHING BUT DOES NOT LOOK THAT IMPRESSIVE FOR NOW. && .CLIMATE...WE HAVE HAD OUR FILL OF CLOUDS IN THE SKY HERE IN VEGAS THE LAST FEW DAYS BUT WHEN IS THE LAST TIME WE HAD 3 DAYS WITH THIS MUCH CLOUD COVER AROUND? BASED ON SUNRISE TO SUNSET CLOUD COVER, THE LAST TIME WE HAD BACK-TO-BACK DAYS WITH A 10 (WHICH MEANS AS CLOUDY AS IT GETS) WAS ON DECEMBER 20TH AND 21ST OF 2010. THOSE AROUND THEN HERE WILL REMEMBER THAT AS A PERIOD WHEN A BARRAGE OF STORMS CAME IN FROM THE PACIFIC. THIS WAS ALSO THE ONLY SUCH PERIOD LOOKING BACK THROUGH SKY COVER RECORDS FOR THE LAST 5 YEARS TO NOVEMBER 2008. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && $$ UPDATE...HARRISON AVIATION...SALMEN PREV DISCUSSION...STACHELSKI/ADAIR FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
254 AM PST SUN NOV 24 2013 .SYNOPSIS...A SLOW MOVING LOW PRESSURE WILL FINALLY PULL AWAY FROM THE AREA TODAY RESULTING IN DRIER CONDITIONS. FURTHER WARMING IS EXPECTED ACROSS THE AREA MONDAY THROUGH WEDNESDAY. ANOTHER AREA OF LOW PRESSURE DROPPING SOUTH NEAR THE CALIFORNIA COAST MAY BRING A FEW SHOWERS MAINLY TO WESTERN PORTIONS OF THE AREA FOR THANKSGIVING DAY AND FRIDAY. && .SHORT TERM...TODAY THROUGH TUESDAY NIGHT. WELL AFTER 3 DAYS OF CLOUDS AND RAIN WE ARE FINALLY IN FOR A CHANGE TODAY IN VEGAS WITH THE POTENTIAL OF SEEING SOME SUNSHINE AS A SLOW MOVING UPPER LEVEL LOW FINALLY HEADS OUT OF THE AREA. THE LATEST WATER VAPOR IMAGERY SHOWS THE CENTER OF THE LOW NEAR PARKER, ARIZONA AS OF EARLY THIS MORNING WITH MOISTURE STILL WRAPPING AROUND THE BACK SIDE OF THE LOW. THE MAIN ISSUE FOR TODAY, ESPECIALLY FOR THIS MORNING, WILL BE HOW QUICKLY WE ARE ABLE TO DRY THINGS OUT ACROSS THE AREA WHICH WILL DETERMINE WHEN SHOWERS COME TO AN END AND HOW QUICKLY ANY LOW AND MID-LEVEL CLOUDS START TO BECOME MORE SCATTERED. THE LATEST RADAR IMAGES FROM KESX SHOW MAINLY LIGHT RETURNS ACROSS THE EASTERN PORTIONS OF THE AREA AND IT IS LIKELY THE RADAR IS OVERSHOOTING SOME OF THE PRECIPITATION. BASED ON THE HRRR AND THE 00Z REGIONAL WRF, THE BEST POTENTIAL FOR ANY SHOWERS THIS MORNING WILL BE ACROSS NORTHERN AND CENTRAL MOHAVE COUNTY, LINCOLN COUNTY AND THE MOUNTAINS OF CLARK COUNTY AND I HAVE KEPT IN 20-30 POPS WITH SOME NEAR 40 POP VALUES (IN THE HIGHEST TERRAIN) OVER THESE AREAS. AS THE LOW LEVELS START TO DRY OUT, WE SHOULD SEE THE LOWER AND MID-LEVEL CLOUDS START TO BECOME MORE SCATTERED IN COVERAGE BY EARLY THIS AFTERNOON ESPECIALLY FROM LINCOLN AND CLARK COUNTIES ON EAST. THERE COULD BE A LITTLE FOG AROUND, MAINLY ALONG THE INTERFACES OF THE HIGHER TERRAIN WHERE THEY HIT THE CLOUD BASES. OUTSIDE OF THE COLORADO CITY AREA WHERE FOG WAS REPORTED EARLIER THIS MORNING, NO OTHER FOG WILL BE PLACED IN THE GRIDS AS THE COVERAGE LOOKS TOO SMALL. WITH THE COLD POOL DEPARTING THE AREA ASSOCIATED WITH THE LOW, A LOT OF WARMING ALOFT WILL TAKE PLACE TODAY. THIS COMBINED WITH SOME SUN WILL MAKE FOR A BIG BOOST IN TEMPS, HOWEVER, HIGHS SHOULD STILL BE ABOUT 10 DEGREES BELOW NORMAL ACROSS THE AREA AND I DID CHOP A FEW DEGREES OFF THE PREVIOUS FORECAST BASED ON THE LATEST GUIDANCE. FOR TONIGHT, SOME LOW AND MID-LEVEL CLOUDS MAY LINGER EARLY ON, OTHERWISE EXPECT A CLEAR SKY. TEMPS SHOULD BE A LITTLE COLDER WITH LESS CLOUD COVER. ONE CONCERN WILL BE IN THE WESTERN PORTIONS OF THE MOJAVE DESERT, MAINLY ACROSS NW SAN BERNARDINO COUNTY AND FAR SW INYO COUNTY, WHERE PATCHY FOG MAY BE POSSIBLE. STATISTICAL GUIDANCE SHOWS NEARLY SATURATED OR SATURATED SFC CONDITIONS TONIGHT (ESPECIALLY THE COLDER MET GUIDANCE) AND BUFKIT SOUNDINGS FROM THE NAM SHOW THE VERY LOW-LEVELS MOISTENING AROUND OR JUST AFTER SUNRISE. I WILL GO AHEAD AND ADD PATCHY FOG IN HERE GIVEN THE WET GROUND FROM THE RECENT RAINS, LIGHT WINDS AND CLEAR SKY EXPECTED INITIALLY TONIGHT, HOWEVER CONFIDENCE IS NOT THE BEST WITH THIS. RIDGING ALOFT IS FORECAST TO SLIDE EAST ACROSS THE AREA FROM MONDAY INTO TUESDAY. THIS WILL RESULT IN FURTHER WARMING WITH HIGHS ABOUT 4-6 DEGREES BELOW NORMAL. AS THE RIDGE AXIS SLIDES EAST ON TUESDAY AND A TROUGH OFFSHORE STARTS TO APPROACH HIGH LEVEL MOISTURE SHOULD START TO SPILL IN FROM THE WEST AND COULD BRING A DECENT AMOUNT OF CIRRUS TO THE AREA FOR TUESDAY NIGHT. .LONG TERM...WEDNESDAY THROUGH SATURDAY...THE PACIFIC SYSTEM THAT IS FORECAST TO APPROACH THE WEST COAST BY LATE WEDNESDAY DOES NOT APPEAR TO HAVE THE MAKINGS OF A SIGNIFICANT STORM FOR OUR FORECAST AREA. THE LATEST MEDIUM RANGE MODELS ARE NOW IN BETTER AGREEMENT WITH THE TRACK OF THE SYSTEM....BRINGING THE CENTER OF THE CLOSED LOW ALONG THE CENTRAL CALIFORNIA COAST THANKSGIVING DAY THEN INDICATING IT WILL TRANSFORM INTO A WEAKER AND ELONGATED POSITIVE TILT TROUGH AS IT SAGS OFF THE SOUTHERN CALIFORNIA COAST FRIDAY AND CONTINUES WORKING TOWARD NORTHERN BAJA SATURDAY. THE BEST CHANCE FOR PRECIPITATION WILL BE ACROSS THE SOUTHERN SIERRA AND THE INYO COUNTY MOUNTAINS THANKSGIVING DAY INTO THURSDAY NIGHT AS A SHORTWAVE EJECTS OUT OF THE COASTAL LOW ACROSS SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA. SNOW WILL BE LIKELY IN THE HIGH SIERRA WITH LESSER CHANCES FOR LIGHT SNOW SHOWERS ACROSS THE REST OF THE INYO COUNTY MOUNTAINS AND THE MOUNTAINS OF SOUTHERN NEVADA. PRECIPITATION CHANCES THEN DIMINISH CONSIDERABLY FRIDAY INTO SATURDAY. CONSIDERING THE SEED FOR THIS SYSTEM IS CURRENTLY A BARELY NOTICEABLE PACIFIC SHORTWAVE NEAR 40N AND THE DATELINE...THERE ARE SURE TO BE SOME CHANGES DURING ITS EVOLUTION. IT BEARS WATCHING BUT DOES NOT LOOK THAT IMPRESSIVE FOR NOW. && .AVIATION...FOR MCCARRAN...THE MAIN ISSUE THIS MORNING WILL BE WITH CIGS. CIGS INITIALLY SHOULD BE AROUND 4K FEET OR SO...BUT SOME DRYING OF THE LOWER LEVELS OF THE ATMOSPHERE TAKES PLACE...LOWER CLOUD BASES SHOULD BECOME MORE IN THE SCT-BKN RANGE WITH CLOUDS BASES MAINLY AOA 5-8K FEET. CLOUDS SHOULD BE EXTENSIVE ALONG THE EDGES OF THE VALLEY WITH MOUNTAIN OBSCURATIONS LIKELY THROUGH 18Z OR SO TODAY. BY 00Z CLOUDS SHOULD BECOME MORE FEW-SCT AOA 5-8K FEET WITH A CLEAR SKY EXPECTED TONIGHT. WINDS SHOULD FAVOR TYPICAL DIURNAL TRENDS THROUGH TONIGHT AT SPEEDS OF 5 KTS OR LESS. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...SHOWERS SHOULD DECREASE IN COVERAGE THIS MORNING AND BE DONE ACROSS ALL AREAS EXCEPT EASTERN MOHAVE COUNTY BY 18Z TODAY AND ANY LINGERING SHOWERS THERE SHOULD END BY 21Z TODAY OR SO. SCT-BKN CLOUDS AOA 5K-8K FEET OTHERWISE TODAY WITH VFR VSBY EXCEPT NEAR ANY FOG THIS MORNING. WINDS OVERALL SHOULD BE 10 KTS OR LESS WITH SPEEDS TRENDING TOWARDS TYPICAL DIURNAL COMPONENTS OR A NORTHERLY DIRECTION. FOR TONIGHT A CLEAR SKY IS EXPECTED WITH WINDS FAVORING DIURNAL TRENDS. PATCHY FG/BR POSSIBLE IN AND AROUND KDAG AND ELSEWHERE IN NW SAN BERNARDINO COUNTY WITH VSBY POTENTIALLY DROPPING TO AT LEAST MVFR. && .CLIMATE...WE HAVE HAD OUR FILL OF CLOUDS IN THE SKY HERE IN VEGAS THE LAST FEW DAYS BUT WHEN IS THE LAST TIME WE HAD 3 DAYS WITH THIS MUCH CLOUD COVER AROUND? BASED ON SUNRISE TO SUNSET CLOUD COVER, THE LAST TIME WE HAD BACK-TO-BACK DAYS WITH A 10 (WHICH MEANS AS CLOUDY AS IT GETS) WAS ON DECEMBER 20TH AND 21ST OF 2010. THOSE AROUND THEN HERE WILL REMEMBER THAT AS A PERIOD WHEN A BARRAGE OF STORMS CAME IN FROM THE PACIFIC. THIS WAS ALSO THE ONLY SUCH PERIOD LOOKING BACK THROUGH SKY COVER RECORDS FOR THE LAST 5 YEARS TO NOVEMBER 2008. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && $$ SHORT TERM/AVIATION/CLIMATE...STACHELSKI LONG TERM...ADAIR FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
910 PM PST SAT NOV 23 2013 .SYNOPSIS...RAIN AND SNOW SHOWERS WILL CONTINUE TONIGHT AS A LOW PRESSURE SYSTEM MOVES EAST ACROSS FAR SOUTHERN CALIFORNIA. GRADUAL CLEARING IS EXPECTED FROM WEST TO EAST SUNDAY AS THE STORM SYSTEM TRACKS INTO WESTERN NEW MEXICO. DRY AND WARMER CONDITIONS CAN BE EXPECTED MONDAY THROUGH WEDNESDAY AS HIGH PRESSURE TRAVERSES THE REGION. THE NEXT STORM SYSTEM MAY BRING A CHANCE OF SHOWERS TO PORTIONS OF THE AREA FROM LATE THANKSGIVING DAY INTO FRIDAY. && .UPDATE...OVERALL RADAR RETURNS ARE ON A DOWNWARD TREND THIS EVENING ALTHOUGH SOME ACTIVITY IS PROBABLY BEING OVERSHOT BY THE RADAR. BASED ON THE LATEST RADAR AS WELL AS THE LATEST HRRR MODEL AND 00Z REGIONAL WRF, I HAVE GONE AHEAD AND MADE SOME MINOR ADJUSTMENTS TO POPS TO FIT THE LATEST TRENDS SUGGESTED BY THESE TOOLS. THE MAIN ISSUE FOR LAS VEGAS FOR THE REST OF TONIGHT WILL BE HOW MUCH MOISTURE WRAPPING AROUND THE BACK SIDE OF THE UPPER LOW IS ABLE TO SQUEEZE OUT ANY ADDITIONAL SHOWER ACTIVITY. IT APPEARS BY MIDNIGHT WE SHOULD BE DONE WITH ANY SHOWERS FOR THE MOST PART AS FORECAST SOUNDINGS FROM THE RAP AND WRF ALL SHOW THE LOWER-LEVELS STARTING TO DRY OUT. I WILL LEAVE ANY WINTER WEATHER PRODUCTS OUT AS THESE AREAS MAY SEE ANOTHER INCH OR TWO OF SNOW AND DEAL WITH THEM WITH THE MORNING PACKAGE BASED ON HOW THINGS TREND. AS FOR FOG TONIGHT, THERE MAY BE SOME IN THE HIGHER ELEVATIONS ALONG THE SLOPES WHERE THE CLOUD BASES ARE AT GROUND LEVEL, BUT IT LOOKS UNLIKELY IN THE LOWER ELEVATIONS AS THE LOW LEVELS HAVE EITHER REALLY DRIED OUT (AS IN BISHOP WHERE DEWPOINTS HAVE DROPPED TO 11F) OR ENOUGH STRATUS REMAINS RIGHT NOW THAT THINGS DO NOT APPEAR THEY WILL CLEAR OUT TO ALLOW ANY FOG TO DEVELOP. FORECAST SOUNDINGS FOR BISHOP AND DAGGETT FROM THE RAP AND WRF BOTH CONFIRM THIS AND ANY FOG WAS YANKED FROM THE GRIDS WITH THIS UPDATE. OTHERWISE THE FORECAST LOOKS IN GOOD SHAPE AS WE LOOK TOWARD A DRIER AND NOT AS DAMP SUNDAY FOR THE AREA. && .AVIATION...FOR MCCARRAN...THE MAIN ISSUE OVERNIGHT WILL BE WITH CIGS AS OVERALL RADAR TRENDS WOULD ONLY SUPPORT A FEW LIGHT RAIN SHOWERS IN AND AROUND THE LAS VEGAS VALLEY THROUGH 08Z SUNDAY OR SO. CIGS INITIALLY SHOULD BE AROUND 4K FEET OR SO...BUT AS SHOWER ACTIVITY ENDS AND SOME SLIGHT DRYING OF THE LOWER LEVELS OF THE ATMOSPHERE TAKES PLACE...LOWER CLOUD BASES SHOULD BECOME MORE IN THE SCT-BKN RANGE AND ANY BKN-OVC CLOUD BASES SHOULD BE MORE IN THE 15-20K FOOT RANGE FOR THE DURATION OF TONIGHT. FURTHER DRYING SHOULD TAKE PLACE ON SUNDAY WITH MAINLY SCT-BKN CLOUDS AOA 5K-8K FEET. CLOUDS SHOULD BE EXTENSIVE ALONG THE EDGES OF THE VALLEY WITH MOUNTAIN OBSCURATIONS LIKELY OVERNIGHT THROUGH 18Z OR SO SUNDAY. WINDS SHOULD FAVOR TYPICAL DIURNAL TRENDS ON SUNDAY AT SPEEDS OF 5 KTS OR LESS. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...MAINLY MVFR CIGS TONIGHT WHERE ANY THICKER CLOUD COVERAGE EXISTS WITH VSBY MAINLY IN THE VFR RANGE AWAY FROM ANY SHOWERS. LOWER VSBY EXPECTED IN ANY SNOW SHOWERS. SHOWERS SHOULD DECREASE IN COVERAGE OVERNIGHT AND BE DONE ACROSS ALL AREAS EXCEPT EASTERN MOHAVE COUNTY BY 18Z SUNDAY AND ANY LINGERING SHOWERS THERE SHOULD END BY 21Z SUNDAY OR SO. SCT-BKN CLOUDS AOA 5K-8K FEET OTHERWISE ON SUNDAY WITH VFR VSBY. WINDS OVERALL SHOULD BE 10 KTS OR LESS WITH SPEEDS TRENDING TOWARDS TYPICAL DIURNAL COMPONENTS OR A NORTHERLY DIRECTION. && .PREVIOUS DISCUSSION... ISSUED AT 240 PM PST SAT NOV 23 2013 .DISCUSSION...RAIN AND SNOW CONTINUED ACROSS THE AREA THIS AFTERNOON AS THE STRONG UPPER LOW WAS MOVING INLAND ALONG THE MEXICO BORDER. SIX HOUR RAINFALL AMOUNTS ENDING AT 220 PM HAVE BEEN GENERALLY FROM A TENTH TO A QUARTER OF AN INCH ACROSS CLARK AND MOHAVE COUNTIES WITH SOMEWHAT LIGHTER AMOUNTS IN MOST OTHER AREAS. WEB CAMS SHOWED CLOUDS AND SNOWFALL LIFTING IN INYO COUNTY AND THE WINTER WEATHER ADVISORY WILL BE ALLOWED TO EXPIRE AT 4 PM. THE ADVISORIES FOR THE SPRING MOUNTAINS AND SHEEP RANGE AND FOR HIGHER ELEVATIONS OF SOUTHERN MOHAVE COUNTY REMAINS IN EFFECT UNTIL 10 AM SUNDAY. THE UPPER LOW WILL MOVE INTO ARIZONA LATE TONIGHT WITH PRECIPITATION CHANCES ENDING IN THE WESTERN PART OF THE FORECAST AREA WHILE CONTINUING IN THE EAST. I KEPT A MENTION OF FOG IN THE FORECAST TONIGHT IN SOME AREAS BUT IF CLOUDS DO NOT CLEAR OUT SOME THE FOG MAY NOT DEVELOP. THE MOST LIKELY PLACES FOR FOG FORMATION TONIGHT WILL BE IN THE VALLEYS OF INYO COUNTY AND IN WESTERN SAN BERNARDINO COUNTY. AS THE LOW CENTER MOVES JUST INTO WESTERN NEW MEXICO LATE SUNDAY...SOME CLEARING WILL DEVELOP WITH PRECIPITATION ENDING BY THE AFTERNOON EXCEPT FOR PERHAPS MOHAVE COUNTY. THE MODELS ARE STILL IN GOOD AGREEMENT WITH A RIDGE OF HIGH PRESSURE TRAVERSING THE AREA MONDAY THROUGH WEDNESDAY LEADING TO DRY CONDITIONS AND A WARMING TREND. THE MODELS STILL DIFFER IN THE HANDLING OF THE NEXT UPPER LOW. AT THIS TIME IT LOOKS LIKE IT WILL PROBABLY MOVE ROUGHLY TO THE CENTRAL CALIFORNIA COAST LATE THURSDAY WITH PRECIPITATION CHANCES SPREADING ACROSS MAINLY INYO COUNTY. THERE IS POTENTIAL FOR THE LOW TO MOVE FARTHER INLAND FRIDAY AND I KEPT A SLIGHT CHANCE OF SHOWERS OVER MOST OF THE FORECAST AREA EXCEPT MOHAVE COUNTY. CONFIDENCE IS LOW AS THE ECMWF REMAINS MUCH LESS PROGRESSIVE WITH THE LOW. BY FRIDAY THE LOW MAY HAVE EITHER WEAKENED SIGNIFICANTLY OR DROPPED OFF SHORE LEADING TO DRY CONDITIONS OVER OUR FORECAST AREA. AGAIN...CONFIDENCE IS LOW. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...WINTER WEATHER ADVISORY UNTIL 10 AM PST SUNDAY FOR NVZ018-019. AZ...WINTER WEATHER ADVISORY UNTIL 11 AM MST SUNDAY FOR AZZ003. CA...NONE. && $$ UPDATE/AVIATION...STACHELSKI PREVIOUS...HARRISON FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
917 PM EST MON NOV 25 2013 .SYNOPSIS... PARTLY TO MOSTLY CLOUDY SKIES ALONG WITH A FEW FLURRIES OR LIGHT SNOW SHOWERS ARE EXPECTED TONIGHT INTO THE FIRST HALF OF TUESDAY AS WEAK ENERGY PASSES TO THE NORTH ACROSS SOUTHERN CANADA. A SIGNIFICANT STORM SYSTEM WILL THEN AFFECT THE AREA TUESDAY NIGHT INTO THURSDAY MORNING WITH WIDESPREAD...AND POSSIBLY HEAVY MIXED PRECIPITATION. THIS WILL LIKELY PROVE PROBLEMATIC FOR HOLIDAY TRAVEL INTERESTS DURING THE PERIOD. SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN EXPECTED BY FRIDAY INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 915 PM EST MONDAY...FORECAST REMAINS ON TRACK...NO SIGNIFICANT CHANGES MADE. PREVIOUS DISCUSSION FROM 652 PM MONDAY... GOING FORECAST IN GOOD SHAPE. LOW PRESSURE SYSTEM CONTINUES TO PASS WELL NORTH OF THE AREA...WITH SECONDARY MOISTURE PLUME PASSING SOUTH. A FEW SNOW SHOWERS REMAIN POSSIBLE OVERNIGHT...ESPECIALLY ACROSS THE HIGHER TERRAIN. LOCAL WRF MODELS AND HRRR ALSO HINTING AT A WEAK LAKE EFFECT BAND COMING OFF LAKE ONTARIO AFTER MIDNIGHT. ANY SNOW ACCUMULATIONS WILL BE LIGHT...A DUSTING TO ONE INCH. OTHERWISE...CLOUDS AND SOUTHWEST FLOW SHOULD KEEP TEMPERATURES FAIRLY STEADY FOR THE REMAINDER OF THE NIGHT...WITH 20S FOR MOST...EXCEPT SOME TEENS IN THE NORTHEAST KINGDOM. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 345 PM EST MONDAY...BY TOMORROW FOCUS TURNS TO DEEPENING LOW PRESSURE RIDING NORTHEAST FROM THE SOUTHEASTERN STATES. MODELS CONTINUE TO SHOW GOOD PHASING OF THIS SYSTEM WITH DIGGING NRN STREAM UPPER TROUGH AND SEE NO REASON TO DISCOUNT THE IDEA OF A WIDESPREAD MIXED/WINTRY PCPN EVENT AFFECTING OUR AREA TOMORROW EVENING INTO WED/WED NT. FIRST SURGE OF WAA-DRIVEN PRECIP SHOULD FALL IN THE FORM OF MIXED SN/PL/FZRA DEPENDING ON LOCALE TUESDAY NIGHT AS INITIAL LOWER TO MID LEVEL THERMAL PROFILES ARE AT OR SLIGHTLY BELOW FREEZING. THE DEVIL IS ALWAYS IN THE DETAILS HOWEVER AND AS WE PROGRESS INTO WEDNESDAY CONFIDENCE IS HIGH THAT THERE WILL BE A SUBSTANTIAL WARM AIR SURGE ALONG AND TO THE IMMEDIATE EAST OF THE PRIMARY LOW TRACK. AT THIS TIME IT APPEARS THAT THIS WILL BE FROM NYC NNE THROUGH VT AND AS MEAN 925-850 MB THERMAL PROFILES SURGE INTO THE +5C TO +10C RANGE MUCH OF THE PCPN SHOULD TRANSITION TO ALL RAIN ACROSS VERMONT DURING THE DAYLIGHT HOURS ON WEDNESDAY. FURTHER WEST ACROSS THE ADIRONDACKS INTO THE SLV...COLDER AIR REMAINS MORE OR LESS ENTRENCHED SO CONSIDERABLY HIGHER CONFIDENCE IN BETTER SNOW/PL ACCUMULATIONS HERE. OTHER CONCERNS INCLUDE A POTENTIAL SIGNIFICANT HYDRO RESPONSE ACROSS SOME OF OUR EASTERN VERMONT RIVERS ON WEDNESDAY. MORE OF THAT BELOW IN THE HYDRO SECTIONS. GIVEN AFOREMENTIONED TIGHT THERMAL GRADIENTS AND MESOSCALE EFFECTS OF COLDER NEAR-SFC LAYERS ETC HAVE LEANED HEAVILY ON THE RAW 4KM WRF 2M TEMPS WHICH APPEAR TO CAPTURE TRENDS THE BEST. SAFE TO SAY QUITE THE NON-DIURNAL TREND IN THOSE TEMPERATURES THROUGH TIME AS THE LOW TRACKS TOWARD...ATOP...AND AWAY FROM THE REGION. BY WEDNESDAY NIGHT...THERMAL PROFILES CRASH SHARPLY AS LOW PULLS AWAY AND DECENT DEFORMATION AXIS PULLS THROUGH THE AREA...ESP NRN NY. THUS CONTINUED ACCUMULATING SNOWS IN NY TO SLOWLY TAPER OFF LATE...AND RAIN TO TRANSITION BACK TO SNOW/SHSN IN VERMONT. OVERALL HOLIDAY TRAVEL IMPACTS LIKELY WITH THIS EVENT. FOR VERMONT THIS WOULD LIKELY OCCUR TUE NT WITH INITIAL WINTRY MIX...THEN AGAIN WED NT AS RAIN TRANSITIONS BACK TO LIGHT/MODERATE ACCUMULATING SNOWS. IN NY..ESP DACKS/SLV...A HIGHER IMPACT EVENT EXPECTED WITH SIGNIFICANT WINTRY MIX/ACCUM SNOWS EXPECTED THROUGH THE PERIOD. AS RESULT OF THE ABOVE THINKING...HAVE UPGRADED WINTER STORM WATCHES TO WINTER WX ADVISORIES FOR OUR CHAMPLAIN VALLEY AND VT COUNTIES...AND WINTER STORM WARNINGS FOR OUR ADIRONDACKS/SLV. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 239 PM EST MONDAY...THANKSGIVING...BIG STORM DEPARTED WITH WITH SOME LEFTOVER MTN -SHSN...BRISK AND COLD WITH WINDS DIMINISHING AS THE DAY PROGRESSES. THEREAFTER...RATHER QUIET AS PERSISTENT TROF OF THE PAST WEEK/TWO GRADUALLY TRANSITIONS INTO ZONAL FLOW. BIG SFC HIGH BUILDS FRI AND CONTS TO DOMINATE THROUGH THE WEEKEND THEN EXITING LATE SUNDAY AND MON WITH RETURN FLOW. IT WILL BE COLD AT THE START WITH A MODERATING TREND WEEKEND AND BEYOND. PCPN WILL BE SPARSE...WITH SOME SNOW OR SNOW/RAIN SHOWERS AS A MID LVL DISTURBANCE MOVES THRU MON...OTHERWISE BACK END OF HOLIDAY TRAVEL SHOULD BE MUCH SMOOTHER THAN THE FRONT END. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... THROUGH 00Z WEDNESDAY...VFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD BUT VFR CEILINGS WILL GRADUALLY LOWER TONIGHT WITH SOME SCATTERED SNOW SHOWERS ACROSS NORTHERN NEW YORK AND KRUT. STEADIER SNOW WITH MVFR CONDITIONS ARRIVES KRUT/KSLK AFTER 22Z TUESDAY BUT NOT TILL AFTER 00Z WEDNESDAY AT REST OF SITES. WINDS SOUTH TO SOUTHWEST WITH SPEEDS AROUND 10 KNOTS AND SOME GUSTS TO 20 KNOTS AT KMSS/KBTV OVERNIGHT INTO TUESDAY MORNING. OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY... 00Z WEDNESDAY THROUGH 18Z THURSDAY...CONDITIONS LOWER INTO THE MVFR AND IFR CATEGORIES TUESDAY NIGHT AND CONTINUE INTO THANKSGIVING MORNING. SNOW DEVELOPS TUESDAY EVENING...WITH MIXED PRECIPITATION LATE TUESDAY NIGHT CHANGING TO RAIN WEDNESDAY AT ALL TERMINALS EXCEPT KMSS/KSLK. PRECIPITATION CHANGES BACK TO SNOW WEDNESDAY NIGHT AND TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY ONWARD...MAINLY VFR AS HIGH PRESSURE BUILD INTO REGION. && .HYDROLOGY... AS OF 345 PM EST MONDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS ALL SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE WIDESPREAD 24-HOUR TOTALS SHOULD RANGE FROM 1.5 TO 2.5 INCHES. WHILE SOME OF THIS WILL OCCUR IN THE FROZEN FORM...MUCH WILL FALL AS LIQUID WITH WATERSHEDS RECEIVING SOME ADDITIONAL INPUT FROM MODEST HIGHER ELEVATION SNOWMELT. AS A RESULT...SUBSTANTIAL WITHIN BANK RISES ARE LIKELY ACROSS MANY EASTERN/SOUTHERN VT WATERSHEDS INCLUDING THE PASSUMPSIC...WELLS AND THE WHITE. IF TRENDS CONTINUE...FLOOD WATCHES MAY BE NEEDED FOR PORTIONS OF THIS AREA TUESDAY NIGHT INTO WEDNESDAY. && .MARINE... AS OF 318 PM EST MONDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT FOR TONIGHT THROUGH TUESDAY MORNING. SOUTHERLY WINDS ON THE BROAD LAKE HAVE BEEN STEADILY INCREASING THROUGH THE DAY...AND WILL CONTINUE TO INCREASE ABOVE ADVISORY LIMITS THIS EVENING AND OVERNIGHT. GENERAL WIND SPEEDS OF 15 TO 25 KNOTS ARE EXPECTED THROUGH TUESDAY MORNING WITH PEAK WINDS OF 20 TO 35 KNOTS LIKELY DURING A 3 HOUR WINDOW AROUND 8 PM THIS EVENING. WINDS SPEEDS OF THIS MAGNITUDE WILL RESULT IN GENERAL WAVE HEIGHTS OF 2 TO 4 FEET...WITH SOME 3 TO 5 FOOTERS POSSIBLE DURING THE PEAK WINDS. WINDS DECREASE BELOW 20 KNOTS TUESDAY AFTERNOON AS PRECIPITATION IN THE FORM OF RAIN AND SNOW MOVES IN FROM THE SOUTH/SOUTHWEST. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 7 AM EST WEDNESDAY FOR VTZ001>012-016>019. NY...WINTER STORM WARNING FROM 5 PM TUESDAY TO 7 AM EST THURSDAY FOR NYZ026-027-029>031-034-087. WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 7 AM EST WEDNESDAY FOR NYZ028-035. && $$ SYNOPSIS...JMG NEAR TERM...MUCCILLI SHORT TERM...JMG LONG TERM...SLW AVIATION...RJS HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
658 PM EST MON NOV 25 2013 .SYNOPSIS... PARTLY TO MOSTLY CLOUDY SKIES ALONG WITH A FEW FLURRIES OR LIGHT SNOW SHOWERS ARE EXPECTED TONIGHT INTO THE FIRST HALF OF TUESDAY AS WEAK ENERGY PASSES TO THE NORTH ACROSS SOUTHERN CANADA. A SIGNIFICANT STORM SYSTEM WILL THEN AFFECT THE AREA TUESDAY NIGHT INTO THURSDAY MORNING WITH WIDESPREAD...AND POSSIBLY HEAVY MIXED PRECIPITATION. THIS WILL LIKELY PROVE PROBLEMATIC FOR HOLIDAY TRAVEL INTERESTS DURING THE PERIOD. SEASONABLY COLD AND MAINLY DRY WEATHER IS THEN EXPECTED BY FRIDAY INTO THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 652 PM EST MONDAY...GOING FORECAST IN GOOD SHAPE. LOW PRESSURE SYSTEM CONTINUES TO PASS WELL NORTH OF THE AREA...WITH SECONDARY MOISTURE PLUME PASSING SOUTH. A FEW SNOW SHOWERS REMAIN POSSIBLE OVERNIGHT...ESPECIALLY ACROSS THE HIGHER TERRAIN. LOCAL WRF MODELS AND HRRR ALSO HINTING AT A WEAK LAKE EFFECT BAND COMING OFF LAKE ONTARIO AFTER MIDNIGHT. ANY SNOW ACCUMULATIONS WILL BE LIGHT...A DUSTING TO ONE INCH. OTHERWISE...CLOUDS AND SOUTHWEST FLOW SHOULD KEEP TEMPERATURES FAIRLY STEADY FOR THE REMAINDER OF THE NIGHT...WITH 20S FOR MOST...EXCEPT TEENS IN THE NORTHEAST KINGDOM. PREVIOUS DISCUSSION FROM 345 PM MONDAY... FORECAST REMAINS ON TRACK AS WE HEAD INTO THE EVENING AND OVERNIGHT HOURS AND ONLY SMALL ADJUSTMENTS WERE NEEDED FOR THE FIRST 12 HOURS OF THE FORECAST...MAINLY TO INCORPORATE MOST RECENT MODEL TRENDS IN SKY COVER AND TEMPERATURES. SOLUTIONS PAINT A SIMILAR STORY...SHOWING NORTHERN STREAM CLIPPER ENERGY PASSING WELL NORTH OF OUR REGION OVERNIGHT. THIS SYSTEM WILL SPREAD PLENTY OF MID TO UPPER LEVEL CLOUD COVER ACROSS THE AREA OVER TIME...BUT DYNAMICAL FORCING FOR PRECIPITATION IS FAIRLY WEAK AND WITH SUCH DRY LOWER LEVELS...IT`S HARD TO SEE MUCH IN THE WAY OF ORGANIZED ACTIVITY OCCURRING WITH THIS SYSTEM. THUS WILL CONTINUE THE IDEA OF A FEW/SCT FLURRIES AND/OR SHSN OVERNIGHT THOUGH MAINLY ACROSS NRN NY/NRN MTN LOCALES. ACCUMULATIONS LIGHT AT BEST...PERHAPS A LOCALIZED INCH OR TWO ABOVE 1500 FEET IN FAVORED LOCALES. CHAMPLAIN/CT RVR VALLEYS MAINLY DRY. WITH DEEPENING SOUTH TO SOUTHWESTERLY FLOW TEMPERATURES WILL EXHIBIT CLASSIC NON-DIURNAL TRENDS...ESPECIALLY FROM THE CHAMPLAIN VALLEY WESTWARD WHICH IS TYPICAL UNDER NOCTURNAL RETURN FLOW EVENTS. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 345 PM EST MONDAY...BY TOMORROW FOCUS TURNS TO DEEPENING LOW PRESSURE RIDING NORTHEAST FROM THE SOUTHEASTERN STATES. MODELS CONTINUE TO SHOW GOOD PHASING OF THIS SYSTEM WITH DIGGING NRN STREAM UPPER TROUGH AND SEE NO REASON TO DISCOUNT THE IDEA OF A WIDESPREAD MIXED/WINTRY PCPN EVENT AFFECTING OUR AREA TOMORROW EVENING INTO WED/WED NT. FIRST SURGE OF WAA-DRIVEN PRECIP SHOULD FALL IN THE FORM OF MIXED SN/PL/FZRA DEPENDING ON LOCALE TUESDAY NIGHT AS INITIAL LOWER TO MID LEVEL THERMAL PROFILES ARE AT OR SLIGHTLY BELOW FREEZING. THE DEVIL IS ALWAYS IN THE DETAILS HOWEVER AND AS WE PROGRESS INTO WEDNESDAY CONFIDENCE IS HIGH THAT THERE WILL BE A SUBSTANTIAL WARM AIR SURGE ALONG AND TO THE IMMEDIATE EAST OF THE PRIMARY LOW TRACK. AT THIS TIME IT APPEARS THAT THIS WILL BE FROM NYC NNE THROUGH VT AND AS MEAN 925-850 MB THERMAL PROFILES SURGE INTO THE +5C TO +10C RANGE MUCH OF THE PCPN SHOULD TRANSITION TO ALL RAIN ACROSS VERMONT DURING THE DAYLIGHT HOURS ON WEDNESDAY. FURTHER WEST ACROSS THE ADIRONDACKS INTO THE SLV...COLDER AIR REMAINS MORE OR LESS ENTRENCHED SO CONSIDERABLY HIGHER CONFIDENCE IN BETTER SNOW/PL ACCUMULATIONS HERE. OTHER CONCERNS INCLUDE A POTENTIAL SIGNIFICANT HYDRO RESPONSE ACROSS SOME OF OUR EASTERN VERMONT RIVERS ON WEDNESDAY. MORE OF THAT BELOW IN THE HYDRO SECTIONS. GIVEN AFOREMENTIONED TIGHT THERMAL GRADIENTS AND MESOSCALE EFFECTS OF COLDER NEAR-SFC LAYERS ETC HAVE LEANED HEAVILY ON THE RAW 4KM WRF 2M TEMPS WHICH APPEAR TO CAPTURE TRENDS THE BEST. SAFE TO SAY QUITE THE NON-DIURNAL TREND IN THOSE TEMPERATURES THROUGH TIME AS THE LOW TRACKS TOWARD...ATOP...AND AWAY FROM THE REGION. BY WEDNESDAY NIGHT...THERMAL PROFILES CRASH SHARPLY AS LOW PULLS AWAY AND DECENT DEFORMATION AXIS PULLS THROUGH THE AREA...ESP NRN NY. THUS CONTINUED ACCUMULATING SNOWS IN NY TO SLOWLY TAPER OFF LATE...AND RAIN TO TRANSITION BACK TO SNOW/SHSN IN VERMONT. OVERALL HOLIDAY TRAVEL IMPACTS LIKELY WITH THIS EVENT. FOR VERMONT THIS WOULD LIKELY OCCUR TUE NT WITH INITIAL WINTRY MIX...THEN AGAIN WED NT AS RAIN TRANSITIONS BACK TO LIGHT/MODERATE ACCUMULATING SNOWS. IN NY..ESP DACKS/SLV...A HIGHER IMPACT EVENT EXPECTED WITH SIGNIFICANT WINTRY MIX/ACCUM SNOWS EXPECTED THROUGH THE PERIOD. AS RESULT OF THE ABOVE THINKING...HAVE UPGRADED WINTER STORM WATCHES TO WINTER WX ADVISORIES FOR OUR CHAMPLAIN VALLEY AND VT COUNTIES...AND WINTER STORM WARNINGS FOR OUR ADIRONDACKS/SLV. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 239 PM EST MONDAY...THANKSGIVING...BIG STORM DEPARTED WITH WITH SOME LEFTOVER MTN -SHSN...BRISK AND COLD WITH WINDS DIMINISHING AS THE DAY PROGRESSES. THEREAFTER...RATHER QUIET AS PERSISTENT TROF OF THE PAST WEEK/TWO GRADUALLY TRANSITIONS INTO ZONAL FLOW. BIG SFC HIGH BUILDS FRI AND CONTS TO DOMINATE THROUGH THE WEEKEND THEN EXITING LATE SUNDAY AND MON WITH RETURN FLOW. IT WILL BE COLD AT THE START WITH A MODERATING TREND WEEKEND AND BEYOND. PCPN WILL BE SPARSE...WITH SOME SNOW OR SNOW/RAIN SHOWERS AS A MID LVL DISTURBANCE MOVES THRU MON...OTHERWISE BACK END OF HOLIDAY TRAVEL SHOULD BE MUCH SMOOTHER THAN THE FRONT END. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THROUGH 00Z WEDNESDAY...VFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD BUT VFR CEILINGS WILL GRADUALLY LOWER TONIGHT WITH SOME SCATTERED SNOW SHOWERS ACROSS NORTHERN NEW YORK AND KRUT. STEADIER SNOW WITH MVFR CONDITIONS ARRIVES KRUT/KSLK AFTER 22Z TUESDAY BUT NOT TILL AFTER 00Z WEDNESDAY AT REST OF SITES. WINDS SOUTH TO SOUTHWEST WITH SPEEDS AROUND 10 KNOTS AND SOME GUSTS TO 20 KNOTS AT KMSS/KBTV OVERNIGHT INTO TUESDAY MORNING. OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY... 00Z WEDNESDAY THROUGH 18Z THURSDAY...CONDITIONS LOWER INTO THE MVFR AND IFR CATEGORIES TUESDAY NIGHT AND CONTINUE INTO THANKSGIVING MORNING. SNOW DEVELOPS TUESDAY EVENING...WITH MIXED PRECIPITATION LATE TUESDAY NIGHT CHANGING TO RAIN WEDNESDAY AT ALL TERMINALS EXCEPT KMSS/KSLK. PRECIPITATION CHANGES BACK TO SNOW WEDNESDAY NIGHT AND TAPERS TO SNOW SHOWERS THURSDAY MORNING. CEILINGS AND VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES BY 18Z THURSDAY AS SNOW SHOWERS COME TO AN END. 18Z THURSDAY ONWARD...MAINLY VFR AS HIGH PRESSURE BUILD INTO REGION. && .HYDROLOGY... AS OF 345 PM EST MONDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH GLOBAL BLENDED SOLUTIONS ALL SUGGEST A DECENT QPF EVENT ACROSS OUR AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT COUNTIES WHERE WIDESPREAD 24-HOUR TOTALS SHOULD RANGE FROM 1.5 TO 2.5 INCHES. WHILE SOME OF THIS WILL OCCUR IN THE FROZEN FORM...MUCH WILL FALL AS LIQUID WITH WATERSHEDS RECEIVING SOME ADDITIONAL INPUT FROM MODEST HIGHER ELEVATION SNOWMELT. AS A RESULT...SUBSTANTIAL WITHIN BANK RISES ARE LIKELY ACROSS MANY EASTERN/SOUTHERN VT WATERSHEDS INCLUDING THE PASSUMPSIC...WELLS AND THE WHITE. IF TRENDS CONTINUE...FLOOD WATCHES MAY BE NEEDED FOR PORTIONS OF THIS AREA TUESDAY NIGHT INTO WEDNESDAY. && .MARINE... AS OF 318 PM EST MONDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT FOR TONIGHT THROUGH TUESDAY MORNING. SOUTHERLY WINDS ON THE BROAD LAKE HAVE BEEN STEADILY INCREASING THROUGH THE DAY...AND WILL CONTINUE TO INCREASE ABOVE ADVISORY LIMITS THIS EVENING AND OVERNIGHT. GENERAL WIND SPEEDS OF 15 TO 25 KNOTS ARE EXPECTED THROUGH TUESDAY MORNING WITH PEAK WINDS OF 20 TO 35 KNOTS LIKELY DURING A 3 HOUR WINDOW AROUND 8 PM THIS EVENING. WINDS SPEEDS OF THIS MAGNITUDE WILL RESULT IN GENERAL WAVE HEIGHTS OF 2 TO 4 FEET...WITH SOME 3 TO 5 FOOTERS POSSIBLE DURING THE PEAK WINDS. WINDS DECREASE BELOW 20 KNOTS TUESDAY AFTERNOON AS PRECIPITATION IN THE FORM OF RAIN AND SNOW MOVES IN FROM THE SOUTH/SOUTHWEST. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 7 AM EST WEDNESDAY FOR VTZ001>012-016>019. NY...WINTER STORM WARNING FROM 5 PM TUESDAY TO 7 AM EST THURSDAY FOR NYZ026-027-029>031-034-087. WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 7 AM EST WEDNESDAY FOR NYZ028-035. && $$ SYNOPSIS...JMG NEAR TERM...JMG/MUCCILLI SHORT TERM...JMG LONG TERM...SLW AVIATION...RJS HYDROLOGY...JMG MARINE...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
211 PM EST SUN NOV 24 2013 .SYNOPSIS... THE NORTH COUNTRY WILL REMAIN UNDER COLD NORTHWESTERLY FLOW FOR TODAY AND TONIGHT...AS LOW PRESSURE REMAINS TO OUR EAST AND HIGH PRESSURE OFF TO OUR WEST. THAT AREA OF HIGH PRESSURE WILL SHIFT EAST OVER THE REGION LATER TONIGHT...FOLLOWED BY ANOTHER LOW FOR MONDAY AFTERNOON INTO TUESDAY. THERE IS THE POTENTIAL FOR A WINTER STORM TO AFFECT THE REGION STARTING LATE TUESDAY NIGHT AND INTO WEDNESDAY NIGHT. HIGH PRESSURE SLOWLY RETURNS FOR THURSDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 931 AM EST SUNDAY...HAVE UPDATED THE FORECAST TO RAISE POPS ACROSS MUCH OF NC/NE VT THROUGH THE DAY...AND TO INTRODUCE AREAS OF BLOWING SNOW IN THESE AREAS. ALSO LOWERED HOURLY AND MAX TEMPERATURES BY A FEW DEGREES BASED OFF CURRENT OBSERVATIONAL DATA AND LATEST LAMP GUIDANCE NUMBERS. COLD DAY ON TAP WITH STRONG AND GUSTY NORTHWESTERLY FLOW CONTINUING. THUS WIND ADVISORIES REMAIN IN PLACE...ESP ACROSS THE HIGHER TERRAIN AND DOWNSLOPE LOCATIONS ALONG THE EASTERN SLOPES OF THE DACKS/GREENS. STRONGEST GUSTS LIKELY THIS AFTERNOON WHEN SECONDARY PRESSURE SURGE PUSHES SOUTH INTO THE REGION. GUSTS IN ADVISORY LOCATIONS IN THE 35 TO 45 MPH RANGE WITH LOCALLY HIGHER GUSTS...SLIGHTLY LESS ELSEWHERE. WHILE MOISTURE CONTINUES TO SLOWLY THIN...LINGERING WRAP- AROUND OROGRAPHICALLY ENHANCED SHSN CONTINUE ACROSS THE NRN MTNS WHERE SOME MINOR ADDITIONAL ACCUMULATIONS WILL BE POSSIBLE TODAY. THIS IS IN CLOSE AGREEMENT WITH LATEST 12/13Z RAP PROGS WHICH HAVE A GOOD HANDLE ON THE CURRENT SITUATION. THUS WILL LEAN IN ITS DIRECTION ACCORDINGLY. WITH DEEPLY MIXED PBL...FROUDE NUMBERS QUITE HIGH SO BEST COVERAGE OF SHSN/ACCUMS FROM THE GREEN MTN SPINE EASTWARD. TEMPERATURES REALLY GOING NOWHERE WITH SUCH STRONG CAA IN PLACE...SO READINGS HOLDING MORE OR LESS STEADY...PERHAPS CLIMBING A DEGREE OR TWO WILL BE ALL WE GET TODAY. WITH THE AFORMENTIONED WINDS THE APPARENT TEMPS SHOULD RANGE IN THE -10F TO +5F RANGE...COLDER TO NEAR -20F AT THE SUMMITS. DEFINITELY A DAY TO WEAR THE FULL WINTER CLOTHING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... AS OF 352 AM EST SUNDAY...TONIGHT WITH RIDGE APPROACHING AND WINDS ABATING...TEMPS WILL DROP SHARPLY TO LOWEST OF THE SEASON SO FAR WITH LOWS RANGING FROM -5 TO 10F IN DACKS TO SINGLE NUMBERS ELSEWHERE. WIND ADVISORY REMAINS IN AFFECT THRU TNGT AS TIGHT GRADIENT CREATING STEADY 15-30 MPH WINDS WITH GUSTS 40-50MPH...HIGHEST OVER DACKS AND E VT. BY 00Z MONDAY...GRADIENT WILL SLACKEN AND TAPER OFF BY MIDNGT WITH ARRIVAL OF SFC RIDGE. WIND CHILL ISSUES POSSIBLE IN RANGE OF 0F TO -10F. COLD CHILLY MORNING ON MONDAY W/ RIDGE CRESTING OVER THE AREA AND SLIDING S AND E DURING THE DAY. THIS WILL ALLOW WAA ON SSW FLOW TO SETUP OVER THE AREA...AND PROVIDE A NICE REBOUND IN TEMPS FROM THE COLD WEEKEND. WAA WILL BRING HIGHS MONDAY INTO THE 20S FOR ALL SITES. INCR CLDS THOUGH OVER N NY AS NORTHERN STREAM SYSTEM COMES OUT OF THE GREAT LKS REGION AND INTO QUEBEC MON AFTNOON/TUESDAY MORNING. BLOCKING RIDGE TO OUR SOUTH WILL PUT BEST POP FOCUS OVER N NY TAPERING DOWN TO SE VT. ADDITIONAL LIGHT SNOWFALL WILL OCCUR BRINGING AROUND AN INCH OF NEW SNOW TAPERING OFF TO A POTENTIAL DUSTING IN SOUTHERN ZONES. CLD COVER KEEPS TEMPS FROM DROPPING TOO MUCH ALONG WITH GRADIENT STAYING SW. LOOKING FOR LOWS IN THE TEENS TO L20S. GOING INTO TUESDAY SW GRADIENT STAYS INTACT FOR THE DAY AS NORTHERN SYSTEM...THAT COULD BRING STORM NEAR THANKSGIVING...SWINGS THRU THE GREAT LKS. CLDS/MOISTURE FEED WILL ALLOW FOR SL CHANCE OF -SW WITH FOCUS OVER SOUTHERN ZONES. OVERALL INCH OR LESS EXPECTED...WITH HIGHS IN THE 30S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 209 PM EST SUNDAY...INALLY SOME CONSENSUS IN ALL MAJOR MODELS WITH THE 12Z GFS BEING THE LATECOMER TO THE PARTY FOR THIS MID WEEK...HOLIDAY TRAVEL STORM. THE SHORT TERM DISCUSSION TOUCHES UPON ALOT OF THE EVOLVING SYSTEM BUT THE CURRENT WED FCST IS BASED ON A GFS/ECMWF/NAM TRACK OF NYC-ORH-CON. CNDN GEM IS MORE HUDSON/CHAMPLAIN VLY BUT ERRING TO A SLIGHTLY COLDER...MORE PROBLEMATIC SOLUTION. IN GENERAL...A SNOW/MIXED START WITH GRADUAL CHANGEOVER TO MIXED/RAIN IN VT AND CHMPL VLY NY WITH SOME POSSIBLE ACCUMULATING SNOW AND A FLASH FREEZE MARCHING FROM WEST TO EAST AFT SFC LOW PASSAGE WED EVE/WED NGT. ADRNDKS/ST LWRNC VLY IN THE POTENTIAL SWEET-SPOT FOR HEAVY SNOWFALL ALONG WITH SOME MIXING. QPF AMOUNTS OF 1-2 INCHES ACROSS MUCH OF THE FA...LIGHTER SIDE ACRS ST LWRNC VLY WHERE IT WILL STAY COLDEST. WPC WINTER WX GRAPHIC PLACES 6-12 INCHES IN ADRNDKS/ST LWRNC VLY AND QUITE POSSIBLE. LLVL NNE JET ACRS ST LWRNV VLY WILL ADD PROBLEMS WITH CONSIDERABLE BLOWING SNOW. LLVL TEMP PROFILES AND SHARP GRADIENT LEADS TO CONCERNS OF ICING IN INTERIOR VT AND CT RVR VLY DUE TO STG INVERSIONS. IN ADDITION...A NNE LLVL FLOW IN ST LWRNC VLY THAT MAY ADVECT LLVL COLD AIR TOWARD NRN CHAMPL VLY FOR A WINTRY MIX. AGAIN...LATE WED/WED NGT AS SFC LOW DEPARTS STG CAA AND WRAPARD PCPN CHANGING TO SNOW AND FALLING TMPS WILL LIKELY RESULT IN A FLASH FREEZE SITUATION ON ROADS...TREES AND UTILITY LINES AND WITH NNW WINDS INCREASING TO 20-30KTS PSBLY BLOWING SNOW AND POWER OUTAGES. THANKSGIVING...BLUSTERY AND LEFTOVER MTN SNOW SHOWERS BUT COLD THROUGHOUT THE DAY. THEREAFTER...CONTINUED BELOW NORMAL TEMPERATURES (10-15 DEGS BLO) CONTINUE THROUGH THE WEEKEND WITH REINFORCING SHOTS OF COLD AIR AND CHC OF FLURRIES. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...STRONG W-NW WINDS WILL CONTINUE INTO THIS EVENING. SNOW SHOWER ACTIVITY IS GRADUALLY DECREASING WITH DRIER AIR MOVING IN...BUT PERIODS OF IFR AT KMPV DUE TO BLOWING SNOW. ELSEWHERE...VFR WITH CLRG SKIES BY AND DURING THE EVENING. KBTV/KMPV WILL SEE WNW WINDS 20G35KTS THRU 00Z MON...ELSEWHERE WILL BE 15-18G28KTS ALL DIMINISHING AFT 04Z. OUTLOOK 18Z MONDAY THROUGH THURSDAY...DRY AND MOSTLY CLEAR VFR WITH HIGH PRESSURE IN PLACE MONDAY. THERE WILL BE A CHANCE FOR MVFR CIGS/VIS IN SNOW SHOWERS MONDAY NIGHT AND TUESDAY AS WEAK UPPER LEVEL TROUGH MOVES ACROSS THE NORTH COUNTRY. MODERATE TO HIGH PREDICTABILITY FOR WEDNESDAY WITH INCREASING CONFIDENCE OF STORM TRACK WITHIN 50 MILES OF A KLGA-KBDL-KORH-KCON LINE. POSSIBILITY EXISTS FOR IFR CONDITIONS WITH ACCUMULATING SNOWFALL AND MIXED WEDNESDAY BUT DETAILS ARE UNCERTAIN. THURSDAY...MODERATE N-NW WINDS WITH ISOLD -SHSN POSSIBLE...MAINLY VCNTY MTNS. TAF LOCATIONS SHOULD BE MAINLY VFR FOR THURSDAY. && .MARINE... AS OF 352 AM EST SUNDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT AND WILL LIKELY REMAIN SO THROUGH TONIGHT. WINDS NORTHWEST 20 TO 30 KNOTS...TAPERING TO 15 TO 25 KNOTS TONIGHT. WAVES WILL BUILD TO 3-5 FEET IMPACTING NORTH-FACING EXPOSURES. && .CLIMATE... THE COLD TEMPERATURES SUNDAY 11/24 INTO MONDAY 11/25 MAY APPROACH RECORD LEVELS. THE RECORDS ARE LISTED BELOW: RECORD LOW AND RECORD LOW MAXIMUMS SUNDAY 11/24: BURLINGTON (BTV)- 2 (1956), 19 (1938) MONTPELIER (MPV)- -4 (1989), 20 (2000) MASSENA (MSS)- -8 (2000), 19 (1996) SAINT JOHNSBURY (SJBV1)- -6 (1989), 20 (1921) RECORD LOW AND RECORD LOW MAXIMUMS MONDAY 11/25: BURLINGTON (BTV)- -1 (1938), 14 (1938) MONTPELIER (MPV)- 4 (1997,1993), 24 (1993,1971) MASSENA (MSS)- 5 (2005), 23 (1993) SAINT JOHNSBURY (SJBV1)- 0 (1956), 19 (1938) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR VTZ003-004- 006>008-010-012-016>019. NY...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ028-031-034- 035. && $$ SYNOPSIS...JN NEAR TERM...JMG SHORT TERM...JN LONG TERM...SLW AVIATION...BANACOS/SLW MARINE...LOCONTO CLIMATE...MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1232 PM EST SUN NOV 24 2013 .SYNOPSIS... THE NORTH COUNTRY WILL REMAIN UNDER COLD NORTHWESTERLY FLOW FOR TODAY AND TONIGHT...AS LOW PRESSURE REMAINS TO OUR EAST AND HIGH PRESSURE OFF TO OUR WEST. THAT AREA OF HIGH PRESSURE WILL SHIFT EAST OVER THE REGION LATER TONIGHT...FOLLOWED BY ANOTHER LOW FOR MONDAY AFTERNOON INTO TUESDAY. THERE IS THE POTENTIAL FOR A WINTER STORM TO AFFECT THE REGION STARTING LATE TUESDAY NIGHT AND INTO WEDNESDAY NIGHT. HIGH PRESSURE SLOWLY RETURNS FOR THURSDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 931 AM EST SUNDAY...HAVE UPDATED THE FORECAST TO RAISE POPS ACROSS MUCH OF NC/NE VT THROUGH THE DAY...AND TO INTRODUCE AREAS OF BLOWING SNOW IN THESE AREAS. ALSO LOWERED HOURLY AND MAX TEMPERATURES BY A FEW DEGREES BASED OFF CURRENT OBSERVATIONAL DATA AND LATEST LAMP GUIDANCE NUMBERS. COLD DAY ON TAP WITH STRONG AND GUSTY NORTHWESTERLY FLOW CONTINUING. THUS WIND ADVISORIES REMAIN IN PLACE...ESP ACROSS THE HIGHER TERRAIN AND DOWNSLOPE LOCATIONS ALONG THE EASTERN SLOPES OF THE DACKS/GREENS. STRONGEST GUSTS LIKELY THIS AFTERNOON WHEN SECONDARY PRESSURE SURGE PUSHES SOUTH INTO THE REGION. GUSTS IN ADVISORY LOCATIONS IN THE 35 TO 45 MPH RANGE WITH LOCALLY HIGHER GUSTS...SLIGHTLY LESS ELSEWHERE. WHILE MOISTURE CONTINUES TO SLOWLY THIN...LINGERING WRAP- AROUND OROGRAPHICALLY ENHANCED SHSN CONTINUE ACROSS THE NRN MTNS WHERE SOME MINOR ADDITIONAL ACCUMULATIONS WILL BE POSSIBLE TODAY. THIS IS IN CLOSE AGREEMENT WITH LATEST 12/13Z RAP PROGS WHICH HAVE A GOOD HANDLE ON THE CURRENT SITUATION. THUS WILL LEAN IN ITS DIRECTION ACCORDINGLY. WITH DEEPLY MIXED PBL...FROUDE NUMBERS QUITE HIGH SO BEST COVERAGE OF SHSN/ACCUMS FROM THE GREEN MTN SPINE EASTWARD. TEMPERATURES REALLY GOING NOWHERE WITH SUCH STRONG CAA IN PLACE...SO READINGS HOLDING MORE OR LESS STEADY...PERHAPS CLIMBING A DEGREE OR TWO WILL BE ALL WE GET TODAY. WITH THE AFORMENTIONED WINDS THE APPARENT TEMPS SHOULD RANGE IN THE -10F TO +5F RANGE...COLDER TO NEAR -20F AT THE SUMMITS. DEFINITELY A DAY TO WEAR THE FULL WINTER CLOTHING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... AS OF 352 AM EST SUNDAY...TONIGHT WITH RIDGE APPROACHING AND WINDS ABATING...TEMPS WILL DROP SHARPLY TO LOWEST OF THE SEASON SO FAR WITH LOWS RANGING FROM -5 TO 10F IN DACKS TO SINGLE NUMBERS ELSEWHERE. WIND ADVISORY REMAINS IN AFFECT THRU TNGT AS TIGHT GRADIENT CREATING STEADY 15-30 MPH WINDS WITH GUSTS 40-50MPH...HIGHEST OVER DACKS AND E VT. BY 00Z MONDAY...GRADIENT WILL SLACKEN AND TAPER OFF BY MIDNGT WITH ARRIVAL OF SFC RIDGE. WIND CHILL ISSUES POSSIBLE IN RANGE OF 0F TO -10F. COLD CHILLY MORNING ON MONDAY W/ RIDGE CRESTING OVER THE AREA AND SLIDING S AND E DURING THE DAY. THIS WILL ALLOW WAA ON SSW FLOW TO SETUP OVER THE AREA...AND PROVIDE A NICE REBOUND IN TEMPS FROM THE COLD WEEKEND. WAA WILL BRING HIGHS MONDAY INTO THE 20S FOR ALL SITES. INCR CLDS THOUGH OVER N NY AS NORTHERN STREAM SYSTEM COMES OUT OF THE GREAT LKS REGION AND INTO QUEBEC MON AFTNOON/TUESDAY MORNING. BLOCKING RIDGE TO OUR SOUTH WILL PUT BEST POP FOCUS OVER N NY TAPERING DOWN TO SE VT. ADDITIONAL LIGHT SNOWFALL WILL OCCUR BRINGING AROUND AN INCH OF NEW SNOW TAPERING OFF TO A POTENTIAL DUSTING IN SOUTHERN ZONES. CLD COVER KEEPS TEMPS FROM DROPPING TOO MUCH ALONG WITH GRADIENT STAYING SW. LOOKING FOR LOWS IN THE TEENS TO L20S. GOING INTO TUESDAY SW GRADIENT STAYS INTACT FOR THE DAY AS NORTHERN SYSTEM...THAT COULD BRING STORM NEAR THANKSGIVING...SWINGS THRU THE GREAT LKS. CLDS/MOISTURE FEED WILL ALLOW FOR SL CHANCE OF -SW WITH FOCUS OVER SOUTHERN ZONES. OVERALL INCH OR LESS EXPECTED...WITH HIGHS IN THE 30S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 640 AM EST SUNDAY...STILL CONSIDERABLE MODEL DIFFERENCES CONCERNING MOISTURE-LADEN SYNOPTIC LOW EXPECTED TO AFFECT THE NORTH COUNTRY TUESDAY NIGHT INTO WEDNESDAY...WHICH UNFORTUNATELY COINCIDES WITH ONE OF THE BUSIEST TRAVEL DAYS OF THE YEAR. THE 00Z NWP DIFFERENCES CONTINUE TO SURROUND INTERACTION BETWEEN VIGOROUS BUT DISTINCT NRN AND SRN STREAM SHORTWAVE TROUGHS AS SYSTEMS CROSS THE OHIO VALLEY AND SERN STATES...RESPECTIVELY. THE DEEPER AND MORE PHASED SOLN OFFERED BY THE 00Z ECMWF TAKES THE LOW INLAND UP THE EAST COAST AND ULTIMATELY TRACKS A 986MB LOW ACROSS VT BETWEEN 18Z WED AND 00Z THU. THIS IS A WARMER SOLN WITH 850MB TEMPS REACHING +8C ACROSS VT AT 18Z WEDNESDAY. ANY SNOW AT THE ONSET TUESDAY NIGHT WOULD SWITCH OVER TO MAINLY RAIN ACROSS THE REGION. MEANWHILE...THE 00Z GFS CONTINUES THAT MODEL/S TENDENCY TO KEEP A FASTER MOVING SYSTEM OFFSHORE BETWEEN THE 40N 70W BENCHMARK AND CAPE COD WITH A 994MB LOW MOVING THROUGH AT 18Z WEDNESDAY. THIS IS A MUCH COLDER SOLN...WITH POTENTIAL ACCUMULATING SNOW ACROSS VT AND LESS PRECIPITATION IMPACT FOR NRN NY. HAVE INCREASED POPS TO 70-80 PERCENT LATE TUESDAY THROUGH WEDNESDAY ASSOCIATED WITH THIS SYSTEM WITH QPF ON THE ORDER OF 1"...BUT IT REMAINS TOO SOON TO DETERMINE P-TYPE DETAILS GIVEN UNCERTAIN EVOLUTION/PHASING OF NRN AND SRN STREAMS. THOSE WITH TRAVEL PLANS WEDNESDAY SHOULD CONSIDER PROSPECT FOR WINTER TRAVEL CONDITIONS ACROSS THE NORTH COUNTRY...BUT THAT IS BY NO MEANS A SURE THING AT THIS POINT. WE/LL MAINTAIN MENTION OF THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. CONDITIONS WILL TREND COLDER AND DRIER FOR THANKSGIVING DAY AS SYNOPTIC LOW DEPARTS NEWD THRU QUEBEC/CANADIAN MARITIMES. NWLY WINDS AT 10-20 MPH WITH A FEW FLURRIES IN THE NRN GREENS INTO NERN VT. LOWS WEDNESDAY NIGHT WILL BE IN THE UPR TEENS TO LOWER 20S...FOLLOWED BY HIGHS MAINLY IN THE 20S FOR THANKSGIVING DAY. HIGH PRESSURE SHOULD BRING DRY AND SEASONABLY COLD CONDITIONS FRIDAY AND SATURDAY. HIGH TEMPS GENERALLY REMAIN IN THE 20S THRU THE END OF THE FORECAST PERIOD SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...STRONG W-NW WINDS WILL CONTINUE INTO THIS EVENING. SNOW SHOWER ACTIVITY IS GRADUALLY DECREASING WITH DRIER AIR MOVING IN...BUT PERIODS OF IFR AT KMPV DUE TO BLOWING SNOW. ELSEWHERE...VFR WITH CLRG SKIES BY AND DURING THE EVENING. KBTV/KMPV WILL SEE WNW WINDS 20G35KTS THRU 00Z MON...ELSEWHERE WILL BE 15-18G28KTS ALL DIMINISHING AFT 04Z. OUTLOOK 18Z MONDAY THROUGH THURSDAY...DRY AND MOSTLY CLEAR VFR WITH HIGH PRESSURE IN PLACE MONDAY. THERE WILL BE A CHANCE FOR MVFR CIGS/VIS IN SNOW SHOWERS MONDAY NIGHT AND TUESDAY AS WEAK UPPER LEVEL TROUGH MOVES ACROSS THE NORTH COUNTRY. MODERATE TO HIGH PREDICTABILITY FOR WEDNESDAY WITH INCREASING CONFIDENCE OF STORM TRACK WITHIN 50 MILES OF A KLGA-KBDL-KORH-KCON LINE. POSSIBILITY EXISTS FOR IFR CONDITIONS WITH ACCUMULATING SNOWFALL AND MIXED WEDNESDAY BUT DETAILS ARE UNCERTAIN. THURSDAY...MODERATE N-NW WINDS WITH ISOLD -SHSN POSSIBLE...MAINLY VCNTY MTNS. TAF LOCATIONS SHOULD BE MAINLY VFR FOR THURSDAY. && .MARINE... AS OF 352 AM EST SUNDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT AND WILL LIKELY REMAIN SO THROUGH TONIGHT. WINDS NORTHWEST 20 TO 30 KNOTS...TAPERING TO 15 TO 25 KNOTS TONIGHT. WAVES WILL BUILD TO 3-5 FEET IMPACTING NORTH-FACING EXPOSURES. && .CLIMATE... THE COLD TEMPERATURES SUNDAY 11/24 INTO MONDAY 11/25 MAY APPROACH RECORD LEVELS. THE RECORDS ARE LISTED BELOW: RECORD LOW AND RECORD LOW MAXIMUMS SUNDAY 11/24: BURLINGTON (BTV)- 2 (1956), 19 (1938) MONTPELIER (MPV)- -4 (1989), 20 (2000) MASSENA (MSS)- -8 (2000), 19 (1996) SAINT JOHNSBURY (SJBV1)- -6 (1989), 20 (1921) RECORD LOW AND RECORD LOW MAXIMUMS MONDAY 11/25: BURLINGTON (BTV)- -1 (1938), 14 (1938) MONTPELIER (MPV)- 4 (1997,1993), 24 (1993,1971) MASSENA (MSS)- 5 (2005), 23 (1993) SAINT JOHNSBURY (SJBV1)- 0 (1956), 19 (1938) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR VTZ003-004- 006>008-010-012-016>019. NY...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ028-031-034- 035. && $$ SYNOPSIS...JN NEAR TERM...JMG SHORT TERM...JN LONG TERM...BANACOS AVIATION...BANACOS/SLW MARINE...LOCONTO CLIMATE...MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
931 AM EST SUN NOV 24 2013 .SYNOPSIS... THE NORTH COUNTRY WILL REMAIN UNDER COLD NORTHWESTERLY FLOW FOR TODAY AND TONIGHT...AS LOW PRESSURE REMAINS TO OUR EAST AND HIGH PRESSURE OFF TO OUR WEST. THAT AREA OF HIGH PRESSURE WILL SHIFT EAST OVER THE REGION LATER TONIGHT...FOLLOWED BY ANOTHER LOW FOR MONDAY AFTERNOON INTO TUESDAY. THERE IS THE POTENTIAL FOR A WINTER STORM TO AFFECT THE REGION STARTING LATE TUESDAY NIGHT AND INTO WEDNESDAY NIGHT. HIGH PRESSURE SLOWLY RETURNS FOR THURSDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 931 AM EST SUNDAY...HAVE UPDATED THE FORECAST TO RAISE POPS ACROSS MUCH OF NC/NE VT THROUGH THE DAY...AND TO INTRODUCE AREAS OF BLOWING SNOW IN THESE AREAS. ALSO LOWERED HOURLY AND MAX TEMPERATURES BY A FEW DEGREES BASED OFF CURRENT OBSERVATIONAL DATA AND LATEST LAMP GUIDANCE NUMBERS. COLD DAY ON TAP WITH STRONG AND GUSTY NORTHWESTERLY FLOW CONTINUING. THUS WIND ADVISORIES REMAIN IN PLACE...ESP ACROSS THE HIGHER TERRAIN AND DOWNSLOPE LOCATIONS ALONG THE EASTERN SLOPES OF THE DACKS/GREENS. STRONGEST GUSTS LIKELY THIS AFTERNOON WHEN SECONDARY PRESSURE SURGE PUSHES SOUTH INTO THE REGION. GUSTS IN ADVISORY LOCATIONS IN THE 35 TO 45 MPH RANGE WITH LOCALLY HIGHER GUSTS...SLIGHTLY LESS ELSEWHERE. WHILE MOISTURE CONTINUES TO SLOWLY THIN...LINGERING WRAP- AROUND OROGRAPHICALLY ENHANCED SHSN CONTINUE ACROSS THE NRN MTNS WHERE SOME MINOR ADDITIONAL ACCUMULATIONS WILL BE POSSIBLE TODAY. THIS IS IN CLOSE AGREEMENT WITH LATEST 12/13Z RAP PROGS WHICH HAVE A GOOD HANDLE ON THE CURRENT SITUATION. THUS WILL LEAN IN ITS DIRECTION ACCORDINGLY. WITH DEEPLY MIXED PBL...FROUDE NUMBERS QUITE HIGH SO BEST COVERAGE OF SHSN/ACCUMS FROM THE GREEN MTN SPINE EASTWARD. TEMPERATURES REALLY GOING NOWHERE WITH SUCH STRONG CAA IN PLACE...SO READINGS HOLDING MORE OR LESS STEADY...PERHAPS CLIMBING A DEGREE OR TWO WILL BE ALL WE GET TODAY. WITH THE AFORMENTIONED WINDS THE APPARENT TEMPS SHOULD RANGE IN THE -10F TO +5F RANGE...COLDER TO NEAR -20F AT THE SUMMITS. DEFINITELY A DAY TO WEAR THE FULL WINTER CLOTHING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... AS OF 352 AM EST SUNDAY...TONIGHT WITH RIDGE APPROACHING AND WINDS ABATING...TEMPS WILL DROP SHARPLY TO LOWEST OF THE SEASON SO FAR WITH LOWS RANGING FROM -5 TO 10F IN DACKS TO SINGLE NUMBERS ELSEWHERE. WIND ADVISORY REMAINS IN AFFECT THRU TNGT AS TIGHT GRADIENT CREATING STEADY 15-30 MPH WINDS WITH GUSTS 40-50MPH...HIGHEST OVER DACKS AND E VT. BY 00Z MONDAY...GRADIENT WILL SLACKEN AND TAPER OFF BY MIDNGT WITH ARRIVAL OF SFC RIDGE. WIND CHILL ISSUES POSSIBLE IN RANGE OF 0F TO -10F. COLD CHILLY MORNING ON MONDAY W/ RIDGE CRESTING OVER THE AREA AND SLIDING S AND E DURING THE DAY. THIS WILL ALLOW WAA ON SSW FLOW TO SETUP OVER THE AREA...AND PROVIDE A NICE REBOUND IN TEMPS FROM THE COLD WEEKEND. WAA WILL BRING HIGHS MONDAY INTO THE 20S FOR ALL SITES. INCR CLDS THOUGH OVER N NY AS NORTHERN STREAM SYSTEM COMES OUT OF THE GREAT LKS REGION AND INTO QUEBEC MON AFTNOON/TUESDAY MORNING. BLOCKING RIDGE TO OUR SOUTH WILL PUT BEST POP FOCUS OVER N NY TAPERING DOWN TO SE VT. ADDITIONAL LIGHT SNOWFALL WILL OCCUR BRINGING AROUND AN INCH OF NEW SNOW TAPERING OFF TO A POTENTIAL DUSTING IN SOUTHERN ZONES. CLD COVER KEEPS TEMPS FROM DROPPING TOO MUCH ALONG WITH GRADIENT STAYING SW. LOOKING FOR LOWS IN THE TEENS TO L20S. GOING INTO TUESDAY SW GRADIENT STAYS INTACT FOR THE DAY AS NORTHERN SYSTEM...THAT COULD BRING STORM NEAR THANKSGIVING...SWINGS THRU THE GREAT LKS. CLDS/MOISTURE FEED WILL ALLOW FOR SL CHANCE OF -SW WITH FOCUS OVER SOUTHERN ZONES. OVERALL INCH OR LESS EXPECTED...WITH HIGHS IN THE 30S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 640 AM EST SUNDAY...STILL CONSIDERABLE MODEL DIFFERENCES CONCERNING MOISTURE-LADEN SYNOPTIC LOW EXPECTED TO AFFECT THE NORTH COUNTRY TUESDAY NIGHT INTO WEDNESDAY...WHICH UNFORTUNATELY COINCIDES WITH ONE OF THE BUSIEST TRAVEL DAYS OF THE YEAR. THE 00Z NWP DIFFERENCES CONTINUE TO SURROUND INTERACTION BETWEEN VIGOROUS BUT DISTINCT NRN AND SRN STREAM SHORTWAVE TROUGHS AS SYSTEMS CROSS THE OHIO VALLEY AND SERN STATES...RESPECTIVELY. THE DEEPER AND MORE PHASED SOLN OFFERED BY THE 00Z ECMWF TAKES THE LOW INLAND UP THE EAST COAST AND ULTIMATELY TRACKS A 986MB LOW ACROSS VT BETWEEN 18Z WED AND 00Z THU. THIS IS A WARMER SOLN WITH 850MB TEMPS REACHING +8C ACROSS VT AT 18Z WEDNESDAY. ANY SNOW AT THE ONSET TUESDAY NIGHT WOULD SWITCH OVER TO MAINLY RAIN ACROSS THE REGION. MEANWHILE...THE 00Z GFS CONTINUES THAT MODEL/S TENDENCY TO KEEP A FASTER MOVING SYSTEM OFFSHORE BETWEEN THE 40N 70W BENCHMARK AND CAPE COD WITH A 994MB LOW MOVING THROUGH AT 18Z WEDNESDAY. THIS IS A MUCH COLDER SOLN...WITH POTENTIAL ACCUMULATING SNOW ACROSS VT AND LESS PRECIPITATION IMPACT FOR NRN NY. HAVE INCREASED POPS TO 70-80 PERCENT LATE TUESDAY THROUGH WEDNESDAY ASSOCIATED WITH THIS SYSTEM WITH QPF ON THE ORDER OF 1"...BUT IT REMAINS TOO SOON TO DETERMINE P-TYPE DETAILS GIVEN UNCERTAIN EVOLUTION/PHASING OF NRN AND SRN STREAMS. THOSE WITH TRAVEL PLANS WEDNESDAY SHOULD CONSIDER PROSPECT FOR WINTER TRAVEL CONDITIONS ACROSS THE NORTH COUNTRY...BUT THAT IS BY NO MEANS A SURE THING AT THIS POINT. WE/LL MAINTAIN MENTION OF THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. CONDITIONS WILL TREND COLDER AND DRIER FOR THANKSGIVING DAY AS SYNOPTIC LOW DEPARTS NEWD THRU QUEBEC/CANADIAN MARITIMES. NWLY WINDS AT 10-20 MPH WITH A FEW FLURRIES IN THE NRN GREENS INTO NERN VT. LOWS WEDNESDAY NIGHT WILL BE IN THE UPR TEENS TO LOWER 20S...FOLLOWED BY HIGHS MAINLY IN THE 20S FOR THANKSGIVING DAY. HIGH PRESSURE SHOULD BRING DRY AND SEASONABLY COLD CONDITIONS FRIDAY AND SATURDAY. HIGH TEMPS GENERALLY REMAIN IN THE 20S THRU THE END OF THE FORECAST PERIOD SATURDAY. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... THROUGH 12Z MONDAY...ARCTIC FRONT HAS PUSHED EAST OF THE REGION AND STRONG W-NW WINDS WILL CONTINUE IN ITS WAKE AT ALL TAF SITES TODAY AND INTO THIS EVENING. SNOW SHOWER ACTIVITY IS GRADUALLY DECREASING WITH DRIER AIR MOVING IN...BUT PERIODS OF IFR SNOW MAY CONTINUE AT MPV/SLK THRU 16Z. AT BTV...NW WINDS 15-20KTS WITH GUSTS TO 28KTS ARE EXPECTED THROUGH 15Z...INCREASING TO 20G34KT DURING THE AFTN HOURS. CEILINGS MAINLY MVFR AREAWIDE...IMPROVING TO VFR LATE TODAY WITH CLEARING AND DIMINISHING WINDS TONIGHT. OUTLOOK 06Z MONDAY THROUGH THURSDAY...DRY AND MOSTLY CLEAR VFR WITH HIGH PRESSURE IN PLACE MONDAY. THERE WILL BE A CHANCE FOR MVFR CIGS/VIS IN SNOW SHOWERS MONDAY NIGHT AND TUESDAY AS WEAK UPPER LEVEL TROUGH MOVES ACROSS THE NORTH COUNTRY. LOW PREDICTABILITY FOR WEDNESDAY WITH UNCERTAIN TRACK OF COASTAL LOW PASSING SE-E OF CAPE COD. POSSIBILITY EXISTS FOR IFR CONDITIONS AND ACCUMULATING SNOWFALL WEDNESDAY BUT DETAILS ARE UNCERTAIN. THURSDAY...MODERATE N-NW WINDS WITH ISOLD -SHSN POSSIBLE...MAINLY VCNTY MTNS. TAF LOCATIONS SHOULD BE MAINLY VFR FOR THURSDAY. && .MARINE... AS OF 352 AM EST SUNDAY...A LAKE WIND ADVISORY REMAINS IN EFFECT AND WILL LIKELY REMAIN SO THROUGH TONIGHT. WINDS NORTHWEST 20 TO 30 KNOTS...TAPERING TO 15 TO 25 KNOTS TONIGHT. WAVES WILL BUILD TO 3-5 FEET IMPACTING NORTH-FACING EXPOSURES. && .CLIMATE... THE COLD TEMPERATURES SUNDAY 11/24 INTO MONDAY 11/25 MAY APPROACH RECORD LEVELS. THE RECORDS ARE LISTED BELOW: RECORD LOW AND RECORD LOW MAXIMUMS SUNDAY 11/24: BURLINGTON (BTV)- 2 (1956), 19 (1938) MONTPELIER (MPV)- -4 (1989), 20 (2000) MASSENA (MSS)- -8 (2000), 19 (1996) SAINT JOHNSBURY (SJBV1)- -6 (1989), 20 (1921) RECORD LOW AND RECORD LOW MAXIMUMS MONDAY 11/25: BURLINGTON (BTV)- -1 (1938), 14 (1938) MONTPELIER (MPV)- 4 (1997,1993), 24 (1993,1971) MASSENA (MSS)- 5 (2005), 23 (1993) SAINT JOHNSBURY (SJBV1)- 0 (1956), 19 (1938) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR VTZ003-004- 006>008-010-012-016>019. NY...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ028-031-034- 035. && $$ SYNOPSIS...JN NEAR TERM...JMG SHORT TERM...JN LONG TERM...BANACOS AVIATION...BANACOS MARINE...LOCONTO CLIMATE...MUCCILLI
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 PM EST MON NOV 25 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP IN THE GULF OF MEXICO TONIGHT...THEN INTENSIFY AND TRACK NORTHEAST ALONG THE CAROLINA AND MID ATLANTIC COAST LATE TUESDAY THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM MONDAY... TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT... MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER... WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT. TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z... WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND DAYBREAK. AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND 15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE... WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN- SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF- LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST FORSYTH COUNTY. LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S). && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 PM MONDAY... TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING. POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1 CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED AMOUNTS AROUND 2.5 INCHES. TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS 15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES FROM PREVIOUS FORECAST. TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT. EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT (10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT. TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY. TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN THE LOW-MID 60S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 325 PM MONDAY... FOR WED/WED NIGHT: MODELS ARE IN GOOD AGREEMENT ON PLACING THE PRIMARY SURFACE LOW NEAR NYC WED MORNING AND THE SECONDARY WEAKER LOW OVER THE VA TIDEWATER... WHICH BOTH CONSOLIDATE INTO A SINGLE LOW OVER MAINE BY DAY`S END. THE SOUTHERN STREAM PORTION OF THE STORM SYSTEM WILL BE WEAKENING AS IT LIFT NORTHEASTWARD THROUGH NC FROM MID MORNING THROUGH EARLY AFTERNOON... BUT IT WILL STILL BE QUITE POTENT INDUCING STRONG FORCING FOR ASCENT AS IT MAINTAINS A NEGATIVE TILT. THE MID-UPPER LEVELS ACCORDING TO FORECAST SOUNDINGS WILL DRY OUT QUITE A BIT IN THE MORNING AS A DRY SLOT PUNCHES IN FROM THE SOUTH... SUGGESTING A TRANSITION TO PATCHY DRIZZLE (OR PERHAPS A LITTLE FREEZING DRIZZLE IN THE FAR NW CWA WHERE SURFACE WET BULB TEMPS WILL BE DROPPING TO AROUND 32F) AS THE COLDER AIR ARRIVES POST-FRONT... WITH THE LOWEST 4 KM OR SO STAYING SATURATED. A SLUG OF DPVA ASSOCIATED WITH THE NORTHERN STREAM PORTION OF THE MID LEVEL LONGWAVE TROUGH SWINGS THROUGH NW NC WED AFTERNOON ATTENDING A DEFORMATION ZONE ALOFT... HOWEVER THESE TOO SHOULD BE WEAKENING AND DON`T APPEAR TO PROVIDE ENOUGH DEEP LAYER LIFT TO RE- SATURATE THE AIR ABOVE -10C. AS SUCH... BELIEVE THAT A FEW WET FLAKES WILL BE POSSIBLE ACROSS THE NW AND FAR NRN PIEDMONT WED AFTERNOON AS THE COLUMN COOLS... BUT IT SHOULD BE INCONSEQUENTIAL GIVEN THE BRIEF WINDOW OF OPPORTUNITY AND LIMITED MOISTURE ALOFT. PASSAGE OF A WEAK POST-FRONTAL SURFACE TROUGH WED AFTERNOON WILL SWING WINDS AROUND TO A UNIFORMLY NW DIRECTION... YIELDING CLEARING SKIES BY EARLY EVENING AS DOWNSLOPE FLOW AND DRY AIR ADVECTION TAKES OVER. WITH A TIGHTENING MSLP GRADIENT DUE TO THE STRENGTHENING DEPARTING SURFACE LOW... THESE BRISK NW WINDS DURING THE DAY ARE EXPECTED TO TOP OUT AT 15-20 MPH SUSTAINED WITH GUSTS OVER 30 MPH POSSIBLE AS STRONG 925 MB WINDS NEAR 35 KT MIX DOWN TO THE SURFACE. WED HIGHS ARE APT TO BE VERY CLOSE TO THE MORNING LOWS... WITH PLUNGING THICKNESSES THROUGH THE DAY WITH STEADY COLD AIR ADVECTION CAUSING TEMPS TO FALL SLOWLY THROUGH THE DAY. EARLY DAY HIGHS FROM THE UPPER 30S NW TO LOWER 60S IN THE EASTERN COASTAL PLAIN... FALLING TO THE MID 30S NW TO MID 40S EAST BY LATE AFTERNOON. DEW POINTS WILL FALL INTO THE TEENS TO LOWER 20S OVERNIGHT WITH CLEARING SKIES... BUT THE CONTINUED LOW LEVEL MIXING WILL KEEP TEMPS FROM FALLING TOO LOW... BUT STILL CHILLY WITH LOWS 22-28. LATE DAY WIND CHILLS ARE EXPECTED TO FALL INTO THE 20S OVER THE PIEDMONT... AND INTO THE TEENS TO AROUND 20 AREAWIDE WED NIGHT WITH DIMINISHING WINDS. FOR THU/THU NIGHT: THE CORE OF THE MID LEVEL TROUGH WILL BE WELL TO OUR NE BY THU MORNING... ALTHOUGH BROAD FLAT TROUGHING WILL PERSIST OVER THE EASTERN CONUS AS A VORTEX SPINS OFF CA WITH WEAK LONGWAVE RIDGING IN BETWEEN. SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WSW AND DRIFT OVER THE SRN/CENTRAL APPALACHIANS AND MID- ATLANTIC THROUGH THU NIGHT. EXPECT A DRY AND SUBSIDING COLUMN WITH JUST A FEW HIGH CLOUDS AS ONE LAST WEAK PERTURBATION SWEEPS OVER THE REGION. MAX TEMPS SHOULD BE COMPARABLE TO YESTERDAY GIVEN A SIMILAR AIR MASS WITH SIMILAR (PERHAPS A BIT HIGHER) PREDICTED THICKNESSES. HIGHS 38-45. MOSTLY CLEAR AND CONTINUED COLD THU NIGHT. LOWS 22-27 LOOK GOOD. FOR FRI THROUGH MON: THE SRN STREAM PORTION OF THE SURFACE HIGH WILL MERGE WITH THE POLAR HIGH TO BE CENTERED OVER MAINE/SW QUEBEC AND NOSE TO THE SSW THROUGH CENTRAL NC FRI THROUGH SAT... AS THE MID LEVEL FLOW OVER THE CENTRAL/ERN CONUS FLATTENS. AN INVERTED TROUGH IS EXPECTED TO FORM ALONG THE SOUTHEAST COAST OVER THE WEEKEND... AND THE ENHANCED ONSHORE-DIRECTED LOW LEVEL FLOW SHOULD PULL INCREASING LOW LEVEL ATLANTIC MOISTURE INTO NC... RESULTING IN INCREASING CLOUDS AS WE HEAD THROUGH SUNDAY. THE MID LEVEL LOW OFF CA LATE IN THE WEEK OPENS UP AND WEAKENS THEN HEADS EASTWARD... AND AS THIS BROAD TROUGH APPROACHES NC FROM THE WEST LATE SUN THROUGH MON... EXPECT A TREND TO MOSTLY CLOUDY SKIES AND A CHANCE OF RAIN AS THE OLD FRONT HEADS NORTHWARD TOWARD NC AS A WARM FRONT. EXPECT A GRADUAL RECOVERY IN TEMPS THROUGH THIS PERIOD... STAYING BELOW NORMAL HOWEVER. HIGHS IN THE 40S TO NEAR 50 FRI/SAT... CLIMBING TO THE 50S TO NEAR 60 FOR SUN/MON. -GIH && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 630 PM MONDAY... POOR AVIATION CONDITIONS TO DEVELOP LATE TONIGHT AND PERSIST INTO WEDNESDAY. HIGH CLOUDS ARE STARTING TO OVERSPREAD THE AREA FROM THE SOUTHWEST...AND THERE ARE SOME INDICATIONS THAT SOME LOW-LEVEL MOISTURE AROUND 3K FT IS ALREADY REACHING AREAS SOUTH AND WEST OF CHARLOTTE. THIS WOULD BE A COUPLE HOUR QUICKER THAN MODEL FORECASTS. THIS TRENDING IN LOW-LEVEL MOISTENING WILL CONTINUE OVERNIGHT WHILE A LOW PRESSURE SYSTEM BEGINS TO TAKE SHAPE OVER THE NORTHERN GULF OF MEXICO. PRECIP SHOULD BEGIN SPREADING ACROSS WESTERN NC AFTER MIDNIGHT...AND A PERIOD OF FREEZING RAIN WILL BE POSSIBLE AT KGSO AND KINT...MAINLY BETWEEN 09Z AND 14Z...BEFORE CHANGING OVER TO ALL RAIN BY MID-MORNING. ELSEWHERE...ALL RAIN IS EXPECTED. CEILINGS WILL ULTIMATELY REACH IFR EVERYWHERE...AND LIKELY LIFR AT KGSO AND KINT AS HEAVIER RAIN MOVES ACROSS THE AREA BY TUESDAY AFTERNOON. LOW CEILINGS WILL PERSIST THROUGH TUESDAY NIGHT FOR MOST AREAS...THOUGH CONFIDENCE IS LOWER AT KFAY AND KRWI...AS A WARM FRONT IS EXPECTED TO MOVED INLAND...WHICH MAY SCATTER SOME OF THE LOW CLOUDS AND INCREASE THE CHANCE OF THUNDERSTORMS OVERNIGHT. LOW-LEVEL WINDSHEAR WILL BE A CONCERN FOR MOST OF THE DAY ON TUESDAY AS WELL. OUTLOOK... MVFR AND IFR CEILINGS WILL LINGER INTO WEDNESDAY BEFORE IMPROVING WEDNESDAY NIGHT AND THURSDAY AS A COLD FRONT SWINGS ACROSS THE AREA ON THE HEELS OF A DEPARTING LOW PRESSURE SYSTEM. A DRIER AND MORE STABLE AIR MASS WILL PERSIST ACROSS THE REGION INTO THE WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...WSS NEAR TERM...BSD SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
958 PM CST MON NOV 25 2013 .UPDATE... ISSUED AT 958 PM CST MON NOV 25 2013 NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. ONLY ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 707 PM CST MON NOV 25 2013 LOW CLOUDS WILL CONTINUE PRIMARILY ALONG AND EAST OF THE MISSOURI RIVER TONIGHT. FURTHERMORE...BOUNDARY LAYER WINDS ARE FORECAST TO REMAIN AROUND 30 KNOTS EAST OF HIGHWAY 83 THROUGH 12Z TUESDAY. GIVEN THE COMBINATION OF LOW CLOUDS AND TURBULENT BOUNDARY LAYER FLOW...ADJUSTED OVERNIGHT LOWS UP BY TWO CATEGORIES...MAINLY EAST OF HIGHWAY 83. HIGH PRESSURE NOSING INTO WESTERN NORTH DAKOTA WILL LIKELY CLEAR OUT THE CLOUDS WEST AFTER MIDNIGHT AND ALLOW TEMPERATURES TO RADIATE INTO THE SINGLE DIGITS WEST OF HIGHWAY 85 BY TUESDAY MORNING. THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 320 PM CST MON NOV 25 2013 A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT. A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW BEING BLOWN NEAR THE WEATHER SENSOR. HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER 20S SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM CST MON NOV 25 2013 LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND. A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/ WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST. THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE MODELS RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 707 PM CST MON NOV 25 2013 MVFR CIGS WILL CONTINUE GENERALLY ALONG AND EAST OF A LINE FROM KISN-KBIS TONIGHT. CONDITIONS WILL GRADUALLY IMPROVE TO VFR FROM WEST TO EAST TUESDAY MORNING. VFR CONDITIONS ARE FORECAST OVER WESTERN AND CENTRAL NORTH DAKOTA BY TUESDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...RP KINNEY LONG TERM...KS AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
708 PM CST MON NOV 25 2013 .UPDATE... ISSUED AT 707 PM CST MON NOV 25 2013 LOW CLOUDS WILL CONTINUE PRIMARILY ALONG AND EAST OF THE MISSOURI RIVER TONIGHT. FURTHERMORE...BOUNDARY LAYER WINDS ARE FORECAST TO REMAIN AROUND 30 KNOTS EAST OF HIGHWAY 83 THROUGH 12Z TUESDAY. GIVEN THE COMBINATION OF LOW CLOUDS AND TURBULENT BOUNDARY LAYER FLOW...ADJUSTED OVERNIGHT LOWS UP BY TWO CATEGORIES...MAINLY EAST OF HIGHWAY 83. HIGH PRESSURE NOSING INTO WESTERN NORTH DAKOTA WILL LIKELY CLEAR OUT THE CLOUDS WEST AFTER MIDNIGHT AND ALLOW TEMPERATURES TO RADIATE INTO THE SINGLE DIGITS WEST OF HIGHWAY 85 BY TUESDAY MORNING. THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 320 PM CST MON NOV 25 2013 A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT. A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW BEING BLOWN NEAR THE WEATHER SENSOR. HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER 20S SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM CST MON NOV 25 2013 LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND. A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/ WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST. THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE MODELS RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 707 PM CST MON NOV 25 2013 MVFR CIGS WILL CONTINUE GENERALLY ALONG AND EAST OF A LINE FROM KISN-KBIS TONIGHT. CONDITIONS WILL GRADUALLY IMPROVE TO VFR FROM WEST TO EAST TUESDAY MORNING. VFR CONDITIONS ARE FORECAST OVER WESTERN AND CENTRAL NORTH DAKOTA BY TUESDAY AFTERNOON. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...RP KINNEY LONG TERM...KS AVIATION...TM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
642 AM CST SUN NOV 24 2013 .UPDATE... ISSUED AT 642 AM CST SUN NOV 24 2013 NO MAJOR CHANGES THIS MORNING. THE RAP AND HRRR CONTINUE TO TRY AND BRING SOME PRECIP IN FROM THE NORTHWEST BY THIS AFTERNOON. HOWEVER...ACTUAL SOUNDINGS AT KBIS AND KINL SHOW VERY DRY AIR BELOW 700MB WHICH FITS WITH THE NAM AND GFS MODELS. THE RAP ALSO SEEMS TO BE OVERDOING PRECIP CURRENTLY OVER CANADA COMPARING MODEL OUTPUT TO SFC OBS. AND EVEN THE RAP HAS THE SHOWERS WEAKENING AS THEY MOVE INTO THE CWA. THINK THAT WE WILL SEE SOME INCREASED CLOUD COVER AND SOME VIRGA WITH THE FRONTAL BOUNDARY...BUT NOTHING REACHING THE GROUND. MADE A FEW MINOR TWEAKS TO TEMPS BUT NO MAJOR CHANGES. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 303 AM CST SUN NOV 24 2013 PRECIP CHANCES AND TEMPERATURES WILL BE THE MAIN FORECAST CHALLENGE THROUGH THE PERIOD. SFC TROUGH DEVELOPING OVER SASK HAS ALLOWED WINDS TO SHIFT BACK TO THE SOUTH AND BECOMING QUITE BREEZY. THE WINDS HAVE HELPED TEMPS CLIMB BACK INTO THE POSITIVE DIGITS...AND SHOULD HELP TEMPS CLIMB INTO THE UPPER 20S TO LOW 30S THIS AFTERNOON. HOWEVER...AN APPROACHING SHORTWAVE CAN BE SEEN ON WV LOOP COMING TOWARDS THE REGION. CANADIAN RADAR SHOWS SOME ACTIVITY OVER CENTRAL MANITOBA...AND MODELS HAVE SOME OF THIS PRECIP CLIPPING THE LAKE OF THE WOODS AREA NEAR 12Z. IT IS UNCERTAIN HOW MUCH IS REACHING THE GROUND AT THIS POINT...BUT WILL KEEP SOME LOW POPS GOING THIS MORNING FOR OUR FAR NORTHEAST. THE MAIN SHORTWAVE WILL DIG FURTHER SOUTH INTO MANITOBA TODAY...AND INTO ONTARIO TONIGHT. THE UPPER SYSTEM SHOULD HELP PUSH THE SFC TROUGH EASTWARD...WITH ANOTHER COLD FRONT MOVING INTO THE REGION THIS EVENING. A FEW OF THE SHORT RANGE MODELS HAVE SOME PRECIP DEVELOPING AHEAD OF THE FRONT THIS AFTERNOON...MAINLY OVER THE NORTHERN CWA. HOWEVER...THERE IS QUITE A BIT OF DRY AIR AT LOW LEVELS...AND AT THIS POINT IT SEEMS LIKE NOTHING WILL REACH THE GROUND. THE LARGER SCALE MODELS ALL KEEP US DRY. WILL LEAVE A MENTION OUT FOR NOW BUT KEEP A CLOSE EYE...AS MODEL THERMAL PROFILES SHOW THAT FZRA COULD BE POSSIBLE IF ANYTHING DOES REACH THE GROUND. ANOTHER...STRONGER SHORTWAVE WILL MOVE INTO SOUTHERN MANITOBA FOR MONDAY. PLENTY OF COLD AIR WILL BE MOVING BACK IN BEHIND THE DEPARTING SFC LOW...KEEPING TEMPS IN THE TEENS SUNDAY NIGHT AND THE 20S INTO MONDAY. THE APPROACHING SHORTWAVE WILL BRING AN INCREASING CHANCE FOR SNOW SHOWERS TO OUR NORTHEASTERN CWA DURING THE DAY ON MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 303 AM CST SUN NOV 24 2013 MONDAY NIGHT...THE SHORTWAVE OVER MANITOBA WILL DIG INTO THE GREAT LAKES...BRINGING A CONTINUED CHANCE FOR SNOW OVER LAKE OF THE WOODS AND DRAGGING ANOTHER SURGE OF COLD AIR BEHIND IT. THE AIR MASS WILL BE QUITE COLD ALTHOUGH WITH CLOUDS AT NIGHT THINK WE WILL NOT BE AS COLD AS SATURDAY MORNING. KEPT LOWS IN THE SINGLE DIGITS AND HIGHS IN THE TEENS. WEDNESDAY THROUGH SATURDAY NIGHT..NORTHWEST FLOW ALOFT CONTINUES WITH CANADIAN SHORT-WAVE PASSING THROUGH THE NORTHERN PLAINS WEDNESDAY AND FRIDAY NIGHT INTO SATURDAY. THE FIRST OF THESE IS EXPECTED TO BE DRY WITH THE BEST MOISTURE/LIFT NORTH OF THE INTERNATIONAL BORDER. THE SECOND MAY BRING A LOW CHANCE FOR LIGHT SNOW FRIDAY NIGHT INTO SATURDAY...ALTHOUGH THERE ARE SOME MAJOR DIFFERENCES BETWEEN THE 00 UTC GFS/ECMWF IN FRONTAL ORIENTATION/ LOCATION/TIMING. WILL FOLLOW ALL BLEND 20 POPS FOR NOW. WEDNESDAY WILL BE THE COOLEST DAY OF THE PERIOD WITH A GRADUAL WARMING TREND INTO THE WEEKEND. EVEN SO...DAILY HIGHS LIKELY TO REMAIN BELOW FREEZING AND MAINLY IN THE 20S. OVERNIGHT LOWS WILL DROP INTO THE TEENS EACH MORNING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 642 AM CST SUN NOV 24 2013 CONDITIONS WILL REMAIN VFR WITH INCREASING HIGH AND MID LEVEL CLOUDS TODAY. CIGS SHOULD BE AT 10000 AT THE LOWEST DURING THE AFTERNOON AS A COLD FRONT MOVES IN. SOUTH WINDS TODAY WILL BE QUITE BREEZY AHEAD OF THE FRONT WITH GUSTS ABOVE 20 KTS BUT WILL SHIFT TO THE WEST BY AFTERNOON AND THE NORTHWEST TONIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...JR LONG TERM...JR/ROGERS AVIATION...JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1139 PM EST SAT NOV 23 2013 .SYNOPSIS... LAKE EFFECT SHOWERS WILL INITIATE IN THE WAKE OF THE COLD FRONT TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE EAST ON SUNDAY AND PERSIST THROUGH MONDAY. A COLD FRONT WILL MOVE ACROSS THE AREA LATE MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... I WILL CONTINUE WITH THE CURRENT FORECAST TREND. THE HRRR MODEL SEEMS TO BE HANDLING THE CURRENT LAKE EFFECT SITUATION WELL. IT SHOWS TWO MAIN BANDS...ONE OVER NW PA AND ONE JUST EAST OF CLE. THE RADAR SHOWS THIS TREND. THE MODEL SHOWS THE BAND EAST OF CLE WEAKENING AFTER 06Z WITH THE BANDS OVER NW PA BECOMING DOMINATE. THE WARNED AREA LOOKS GOOD. I AM A LITTLE UNEASY ABOUT LAKE...GEAUGA...EASTERN CUYAHOGA AND THE NORTHERN SECTIONS OF PORTAGE AND SUMMIT. CURRENT FORECAST OF 2 TO 4 INCHES LOOKS REASONABLE BUT VALUES COULD CLIMB TO NEAR LAKE EFFECT ADVISORY LEVELS IF THE BAND EAST OF CLEVELAND PERSISTS. I WILL CONTINUE TO MONITOR BUT AN ADVISORY WILL NOT BE ISSUED WITH THIS UPDATE. PREVIOUS DISCUSSION... THE COLD FRONT IS CURRENTLY SOUTHEAST OF THE AREA. TEMPERATURES WILL CONTINUE TO DROP STEADILY BEHIND THE FRONT DUE TO STRONG COLD AIR ADVECTION. COLDER TEMPERATURES WILL LEAD TO EXTREME INSTABILITY OVER LAKE ERIE...INITIATING LAKE EFFECT SNOW. THERE IS STILL SOME QUESTION AS TO HOW STRONG THE LAKE EFFECT SNOW WILL BECOME. 850 MB TEMPERATURES AROUND 25C WILL PROVIDE ENOUGH INSTABILITY TO PRODUCE HEAVY SNOW...BUT MOISTURE WILL BE LIMITED DUE TO SHORT FETCH WITH NORTHWEST WINDS. ONE WAY TO GET ADDED MOISTURE IS FOR THE LAKE EFFECT TO DEVELOP A CONNECTION TO ANOTHER LAKE. MODELS ARE HINTING AT A LAKE HURON CONNECTION WITH THIS EVENT AND IF THAT OCCURS WE MAY GET THE ADDED MOISTURE NECESSARY TO REALLY GET THINGS GOING. SNOW ACCUMULATIONS ARE ALSO A BIT TRICKY AND DEPEND ON WHETHER OR NOT WE GET THAT LAKE HURON CONNECTION. ASSUMING WE GET THE CONNECTION...WE COULD SEE ANYWHERE FROM SIX INCHES TO OVER A FOOT OF SNOW OVER EXTREME NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. THE AREAS MOST LIKELY TO SEE OVER A FOOT OF SNOW ARE THE IN THE HIGHER TERRAIN OF NORTHWEST PENNSYLVANIA WHERE UPSLOPE FLOW WILL ENHANCE THE LAKE EFFECT SNOW. SEVERAL SECONDARY BANDS MAY DEVELOP TO THE WEST OF THE PRIMARY BAND. THE SECONDARY BANDS DO NOT LOOK LIKE THEY WILL PRODUCE ENOUGH SNOW TO REACH ADVISORY CRITERIA. THE EVENING SHIFT WILL CONTINUE TO MONITOR THE SITUATION AS IT EVOLVES AND ISSUE AN ADVISORY IF THEY BELIEVE IT TO BE NECESSARY. AS FOR TEMPERATURES TONIGHT...COLD AIR ADVECTION WILL CONTINUE OVERNIGHT WITH OVERNIGHT LOWS REACHING INTO THE TEENS FOR MANY LOCATIONS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... HIGH PRESSURE WILL MOVE EAST INTO THE AREA ON SUNDAY...HELPING TO TAPER THE LAKE EFFECT SNOW SUNDAY EVENING. WE WILL GET A BRIEF RESPITE FROM THE SNOW ON MONDAY AS THE HIGH PRESSURE SLIDES EAST. A COLD FRONT WILL CROSS THE AREA LATE MONDAY NIGHT INTO TUESDAY MORNING. NOT EXPECTING MUCH IN THE WAY OF SNOW WITH THE FRONTAL PASSAGE. FOR NOW...GOING WITH A CHANCE OF SNOW SHOWERS FOR MOST OF THE FORECAST AREA. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... COLD AND MAINLY QUIET WEATHER IS EXPECTED DURING THE LONG TERM PERIOD. SOME LAKE EFFECT IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY BUT WINDS QUICKLY BECOME UNFAVORABLE ON WEDNESDAY EVENING. IT APPEARS THAT MOST OF THE LAKE EFFECT WILL BE NUISANCE TYPE ACTIVITY AND AM NOT ANTICIPATING ANY HEADLINES. THURSDAY THROUGH SATURDAY LOOK TO BE DRY. HIGH TEMPS DURING THE PERIOD WILL CONTINUE TO BE 10 TO 15 DEGREES BELOW NORMAL. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... LIMITED LAKE EFFECT WITH REALLY DRY AIR WORKING INTO THE AREA. DEWPOINTS ARE IN THE SINGLE DIGITS. ERIE AND VICINITY WILL HAVE THE HEAVIEST LAKE EFFECT AS A LAKE EFFECT SNOW BAND WITH CONNECTIONS TO LAKE HURON WOBBLES BETWEEN THE OH/PA BORDER AND ERI. THIS WILL PRODUCE PREDOMINATELY IFR CONDITIONS. OUTSIDE OF THIS BAND SNOW SHOWERS ARE HIT OR MISS AND WITH NON VFR CONDITIONS BRIEF AND TEMPORARY. GUSTS FROM CLE/CAK EASTWARD WILL CONTINUE OVERNIGHT TO BE AROUND 25 KTS TO OCCASIONALLY 30 KNOTS. FOR SUNDAY HIGH PRESSURE BEGINS TO BUILD INTO THE OHIO VALLEY...TAPERING THE LAKE EFFECT FURTHER AND DIMINISHING WINDS AND BRINGING THEM AROUND TO THE WEST. FAR EASTERN SITES WILL SEE THIS TAKE PLACE NEAR OR AFTER 00Z MON. LARGELY VFR SUNDAY...WITH THE EXCEPTION OF THE LIMITED LAKE EFFECT ACROSS FAR NE OH/NW PA. OUTLOOK...NON VFR MAINLY OVER NE OH AND NW PA SUNDAY NIGHT BECAUSE OF LAKE EFFECT. MORE WIDESPREAD SYNOPTIC SNOW EXPECTED LATE MONDAY NIGHT INTO TUESDAY AND CONTINUING ACROSS NE OH/NW PA ON WEDNESDAY IN LAKE EFFECT SHSN...AND THEREFORE NON-VFR CONDITIONS. && .MARINE... HAVE ISSUED THE GALE WARNING FOR THE CENTRAL AND EASTERN PORTIONS OF LAKE ERIE. WINDS QUICKLY RAMPED UP ABOVE 30 KNOTS AND HAVE BEEN GALE FORCE. THE OUTLOOK FOR THE REMAINDER OF THE NIGHT IS LOW END GALES...DIMINISHING SUNDAY MORNING. THE FLOW WILL FINALLY BECOME WEST SUNDAY EVENING AND THEN SW BY DAYBREAK MONDAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTH. SOUTHWEST FLOW IS EXPECTED TO CONTINUE TILL ANOTHER COLD FRONT CROSSES THE LAKE ON TUESDAY. THIS WILL BRING MORE CHANCES FOR PRECIP AND NW FLOW BACK TO THE LAKE. WINDS WILL BECOME NORTHERLY ON WEDNESDAY AND NE ON THURSDAY S ARCTIC HIGH PRESSURE BUILDS IN FROM THE NORTH. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT EST SUNDAY NIGHT FOR OHZ014-089. PA...LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT EST SUNDAY NIGHT FOR PAZ001>003. MARINE...GALE WARNING UNTIL 4 AM EST SUNDAY FOR LEZ061-146>149-166>169. SMALL CRAFT ADVISORY UNTIL 11 AM EST TUESDAY FOR LEZ142>145. && $$ SYNOPSIS...SCHEPEL NEAR TERM...GARNET SHORT TERM...SCHEPEL LONG TERM...KUBINA AVIATION...OUDEMAN MARINE...KUBINA/OUDEMAN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
850 PM CST MON NOV 25 2013 .UPDATE... STRATUS SHIELD CONTS TO SLIDE SE ACROSS NERN PART OF SOUTH DAKOTA OVERNIGHT...CREATING A DIFFICULT FORECAST FOR OVERNIGHT LOWS. TEMPS UNDER THE CLOUD SHIELD HAVE NOT FALLEN OFF GREATLY FROM THE AFTERNOON READINGS...WITH TEMPS AOA 30 DEGREES AND HOLDING STEADY. FURTHER SW...CLEAR SKIES ARE ENABLING TEMPS IN THE FAR SW CWA TO FALL...ALBEIT SLOWLY...BUT FALLING NONE THE LESS. THE PROBLEM ARISES WHEN TRYING TO TIME THE BACK EDGE OF THE CLOUD SHIELD AS IT HAS PUSHED INTO NRN ND ATTM WITH TEMPS ACROSS SRN CANADA IN THE SINGLE DIGITS ABOVE ZERO. SENT OUT EARLIER UPDATE TO SLOW THE TEMP FALL ACROSS THE CWA...AND RAISE LOWS ABOUT A CATEGORY ACROSS THE NE. ALSO MANUALLY ADJUSTED THE HOURLY TEMP GRIDS...KEEPING TEMPS UP THROUGH 10Z OR SO...THEN IN ANTICIPATION OF CLEARING LINE...ALLOWED TEMPS TO FALL TO FORECAST LOWS AROUND 13Z TO 14Z. ISOLD FLURRIES ARE STILL BEING REPORTED ACROSS ERN SECTIONS OF ND...AND STILL SEEMS PRUDENT TO KEEP THEM IN ONGOING FCST. ALSO TWEAKED SKY GRIDS TO BETTER MATCH CURRENT CLOUD SHIELD LOCATION AND WINDS ARE ALSO STAYING UP JUST A BIT. UPDATED ZONE FORECAST SENT OUT EARLIER. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850 MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES. WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND 0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS 925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING. HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN REMAINS COLD. .LONG TERM...THURSDAY THROUGH SUNDAY NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT. DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA. EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE PACIFIC NORTHWEST. && .AVIATION... 00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS MVFR/LOW VFR STRATUS CONTS TO MOVE SOUTHEAST THROUGH THE NERN PART OF SOUTH DAKOTA. WITH NAM12 SHOWING WEAK 500HPA VORT MAX COMING DOWN BACKSIDE OF WRN CONUS RIDGE...EXPECT DECK TO HOLD FIRM THROUGH 12Z FOR THE KABR/KATY TERMINALS. UPSTREAM OBS SHOW ISOLD AREAS OF LIGHT SNOW/FLURRIES...AND ALTHOUGH CANT RULE OUT ANY LIGHT SNOW OCCURRING...IMPACT WILL BE MINIMAL WITH NO REDUCTION TO VSBYS EXPECTED...SO HAVE LEFT ANY MENTION OUT. KPIR IS EXPECTED TO BE VFR THROUGH VALID FORECAST PERIOD...WHILE KMBG WILL BE SCT-BKN MVFR/LOW VFR THROUGH 12Z AS THEY RESIDE ON EDGE OF SAGGING STRATUS DECK. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...HINTZ SHORT TERM...TMT LONG TERM...SERR AVIATION...HINTZ WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
542 PM CST MON NOV 25 2013 .UPDATE... 00Z AVIATION DISCUSSION BELOW. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850 MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES. WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND 0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS 925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING. HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN REMAINS COLD. .LONG TERM...THURSDAY THROUGH SUNDAY NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT. DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA. EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE PACIFIC NORTHWEST. && .AVIATION... 00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS MVFR/LOW VFR STRATUS CONTS TO MOVE SOUTHEAST THROUGH THE NERN PART OF SOUTH DAKOTA. WITH NAM12 SHOWING WEAK 500HPA VORT MAX COMING DOWN BACKSIDE OF WRN CONUS RIDGE...EXPECT DECK TO HOLD FIRM THROUGH 12Z FOR THE KABR/KATY TERMINALS. UPSTREAM OBS SHOW ISOLD AREAS OF LIGHT SNOW/FLURRIES...AND ALTHOUGH CANT RULE OUT ANY LIGHT SNOW OCCURRING...IMPACT WILL BE MINIMAL WITH NO REDUCTION TO VSBYS EXPECTED...SO HAVE LEFT ANY MENTION OUT. KPIR IS EXPECTED TO BE VFR THROUGH VALID FORECAST PERIOD...WHILE KMBG WILL BE SCT-BKN MVFR/LOW VFR THROUGH 12Z AS THEY RESIDE ON EDGE OF SAGGING STRATUS DECK. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...HINTZ SHORT TERM...TMT LONG TERM...SERR AVIATION...HINTZ WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
701 PM CST MON NOV 25 2013 .UPDATE... ISSUED A WINTER WEATHER ADVISORY THROUGH THE EVENING AS AN AREA OF LIGHT FREEZING DRIZZLE AND FOG WAS SPREADING SOUTHWARD THROUGH MOST OF THE AREA. ALSO EXPECT FLURRIES. MOST SOLUTIONS DIMINISH THE SHALLOW LIFT AND THIN THE NEAR-SURFACE MOIST LAYER AROUND MIDNIGHT. RMCQUEEN && .PREV DISCUSSION... /ISSUED 547 PM CST MON NOV 25 2013/ AVIATION... A LOW STRATUS LAYER BEHIND THIS AFTERNOONS COLD FRONT WAS EDGING SOUTHWARD TOWARDS KLBB EARLY THIS EVENING AND SHOULD MAKE IT INTO KLBB VERY SHORTLY AFTER 00Z. LATEST RAP SOUNDINGS STEADILY LOWER CEILING AT KLBB TO LIFR LEVELS EARLY THIS EVENING...THOUGH THE HRRR RUN REVEALS LESS CERTAINTY. WE HAVE CONTINUED PREVIOUS IDEA OF AN LIFR LAYER THIS EVENING INTO KLBB...AND EVEN ADDED TEMP LIGHT FOG AND FREEZING DRIZZLE BASED ON UPSTREAM REPORTS. THERE IS ALSO A LOW RISK OF A HARD DROP IN VISIBILITY AS THIS IS EMANATING OFF THE HEAVY SNOW FIELD...THOUGH NOT EXPLICIT FOR KLBB IN ANY GUIDANCE AT THE MOMENT. FOR KCDS...THE CURRENT IFR/LIFR CIG SHOULD HOLD FOR SEVERAL HOURS BEFORE BREAKING...AT LEAST BASED ON SHORT RANGE MODEL TRENDS. UNCERTAIN FOR KCDS IS IF FOG COULD REDEVELOP LATER TONIGHT PER RAP SURFACE HUMIDITY PROGS. WILL STUDY FURTHER FOR 06Z CYCLE. CONDITIONS EXPECTED TO BE ALL VFR TUESDAY. RMCQUEEN PREV DISCUSSION... /ISSUED 300 PM CST MON NOV 25 2013/ SHORT TERM... UPPER LEVEL LOW WHICH HELPED FEED MOISTURE IN FOR THE WEEKEND WINTER WEATHER STORM WAS OVER THE PANHANDLE AT MID DAY. THE LOW CENTER WILL MAKE AN INTERESTING TRAJECTORY DIGGING SOUTHWARD THIS EVENING AND MAKING IT INTO THE TX HILL COUNTRY BY TUESDAY MORNING BEFORE EJECTING NORTHEASTWARD AS IT PHASES WITH A MAIN STREAM DIVING THROUGH MANITOBA THIS AFTERNOON. THIS WILL RESULT IN NORTHERLY FLOW AND MUCH DRIER CONDITIONS SETTING IN. LOWS TONIGHT WILL BE TRICKY AS SKIES ARE EXPECTED TO CLEAR NW TO SE AROUND SUNRISE TUESDAY MORNING. GIVEN THE PROXIMITY OF THE UPPER LOW...WE MAY SEE A FEW FLURRIES OVERNIGHT WINDS SHOULD REMAIN UP AROUND 10 KTS AND THOUGH WIDESPREAD SNOWFALL REMAINS ON THE GROUND...COMBINATION OF SPEEDS AND DOWNSLOPE TRAJECTORY SHOULD KEEP FOG THREAT TO A MINIMUM THOUGH GIVEN THE SNOW-PACK...WILL GO AHEAD AND MENTION PATCHY FOG NORTHWEST. SUNNY AND MUCH WARMER TUESDAY. LONG TERM... HIGH AMPLITUDE RIDGE IN PLACE ACROSS THE ROCKIES TO BEGIN THE EXTENDED PERIOD TUESDAY NIGHT AND WEDNESDAY. SHOULD BE RATHER COLD AGAIN OVER DEEPER SNOW-PACK SRN PANHANDLE WITH TEMPS AGAIN IN THE TEENS. IF WINDS ARE LIGHT ENOUGH...COULD SEE SOME SINGLE DIGITS. 40S AREAWIDE FOR HIGHS WEDNESDAY...AND THEN 50S ON THURSDAY AS FLAT UPPER RIDGE AXIS MOVES EAST OVER THE CENTRAL AND SOUTHERN PLAINS. MAY BE PUSHING 55-60 DEGREES SOUTH BY FRIDAY AS SURFACE LEE TROUGH DEEPENS FROM ERN CO INTO NERN NM AND WEST TEXAS. NEXT SYSTEM OF INTEREST IS POS TILTED OPEN WAVE THAT WILL APPROACH THE AREA OVER THE WEEKEND. SHOULD BEGIN TO SEE SOME MOISTURE RETURN LATE FRIDAY AND SATURDAY AS SOUTHERLY WINDS INCREASE...LIKELY SOME LOW CLOUDS CENTRAL AND EAST SECTIONS. GFS FOR NOW KEEPS SHOWERS EAST OF THE AREA. MAY SEE FRONT INTO AREA ON SUNDAY. PROGRESSIVE NATURE OF SYSTEM LIKELY MEANS A DRY FRONT...AND ONLY SLIGHT COOL-DOWN. BOTH GFS AND PREV ECMWF ADVERTISING BIG PATTERN CHANGE WEDNESDAY OF NEXT WEEK (DEC. 4) WITH CRASHING HEIGHTS OVER THE WESTERN CONUS. IF SOME SEMBLANCE OF THIS PATTERN IS REALIZED...COULD TURN MUCH COLDER AROUND THIS TIME...WITH WINTER WEATHER POSSIBLY MAKING A RETURN. DOES BEAR WATCHING. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 14 36 17 39 23 / 10 0 0 0 0 TULIA 19 38 18 39 23 / 10 0 0 0 0 PLAINVIEW 22 41 20 44 25 / 10 0 0 0 0 LEVELLAND 21 45 20 44 25 / 10 0 0 0 0 LUBBOCK 23 45 22 48 27 / 10 0 0 0 0 DENVER CITY 23 46 23 48 25 / 10 0 0 0 0 BROWNFIELD 23 46 22 48 25 / 10 0 0 0 0 CHILDRESS 23 47 24 45 26 / 10 0 0 0 0 SPUR 26 48 22 48 27 / 10 0 0 0 0 ASPERMONT 25 49 26 48 29 / 10 10 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING ZONES: TXZ021>037-039>042. && $$ 05/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
547 PM CST MON NOV 25 2013 .AVIATION... A LOW STRATUS LAYER BEHIND THIS AFTERNOONS COLD FRONT WAS EDGING SOUTHWARD TOWARDS KLBB EARLY THIS EVENING AND SHOULD MAKE IT INTO KLBB VERY SHORTLY AFTER 00Z. LATEST RAP SOUNDINGS STEADILY LOWER CEILING AT KLBB TO LIFR LEVELS EARLY THIS EVENING...THOUGH THE HRRR RUN REVEALS LESS CERTAINTY. WE HAVE CONTINUED PREVIOUS IDEA OF AN LIFR LAYER THIS EVENING INTO KLBB...AND EVEN ADDED TEMP LIGHT FOG AND FREEZING DRIZZLE BASED ON UPSTREAM REPORTS. THERE IS ALSO A LOW RISK OF A HARD DROP IN VISIBILITY AS THIS IS EMANATING OFF THE HEAVY SNOW FIELD...THOUGH NOT EXPLICIT FOR KLBB IN ANY GUIDANCE AT THE MOMENT. FOR KCDS...THE CURRENT IFR/LIFR CIG SHOULD HOLD FOR SEVERAL HOURS BEFORE BREAKING...AT LEAST BASED ON SHORT RANGE MODEL TRENDS. UNCERTAIN FOR KCDS IS IF FOG COULD REDEVELOP LATER TONIGHT PER RAP SURFACE HUMIDITY PROGS. WILL STUDY FURTHER FOR 06Z CYCLE. CONDITIONS EXPECTED TO BE ALL VFR TUESDAY. RMCQUEEN && .PREV DISCUSSION... /ISSUED 300 PM CST MON NOV 25 2013/ SHORT TERM... UPPER LEVEL LOW WHICH HELPED FEED MOISTURE IN FOR THE WEEKEND WINTER WEATHER STORM WAS OVER THE PANHANDLE AT MID DAY. THE LOW CENTER WILL MAKE AN INTERESTING TRAJECTORY DIGGING SOUTHWARD THIS EVENING AND MAKING IT INTO THE TX HILL COUNTRY BY TUESDAY MORNING BEFORE EJECTING NORTHEASTWARD AS IT PHASES WITH A MAIN STREAM DIVING THROUGH MANITOBA THIS AFTERNOON. THIS WILL RESULT IN NORTHERLY FLOW AND MUCH DRIER CONDITIONS SETTING IN. LOWS TONIGHT WILL BE TRICKY AS SKIES ARE EXPECTED TO CLEAR NW TO SE AROUND SUNRISE TUESDAY MORNING. GIVEN THE PROXIMITY OF THE UPPER LOW...WE MAY SEE A FEW FLURRIES OVERNIGHT WINDS SHOULD REMAIN UP AROUND 10 KTS AND THOUGH WIDESPREAD SNOWFALL REMAINS ON THE GROUND...COMBINATION OF SPEEDS AND DOWNSLOPE TRAJECTORY SHOULD KEEP FOG THREAT TO A MINIMUM THOUGH GIVEN THE SNOW-PACK...WILL GO AHEAD AND MENTION PATCHY FOG NORTHWEST. SUNNY AND MUCH WARMER TUESDAY. LONG TERM... HIGH AMPLITUDE RIDGE IN PLACE ACROSS THE ROCKIES TO BEGIN THE EXTENDED PERIOD TUESDAY NIGHT AND WEDNESDAY. SHOULD BE RATHER COLD AGAIN OVER DEEPER SNOW-PACK SRN PANHANDLE WITH TEMPS AGAIN IN THE TEENS. IF WINDS ARE LIGHT ENOUGH...COULD SEE SOME SINGLE DIGITS. 40S AREAWIDE FOR HIGHS WEDNESDAY...AND THEN 50S ON THURSDAY AS FLAT UPPER RIDGE AXIS MOVES EAST OVER THE CENTRAL AND SOUTHERN PLAINS. MAY BE PUSHING 55-60 DEGREES SOUTH BY FRIDAY AS SURFACE LEE TROUGH DEEPENS FROM ERN CO INTO NERN NM AND WEST TEXAS. NEXT SYSTEM OF INTEREST IS POS TILTED OPEN WAVE THAT WILL APPROACH THE AREA OVER THE WEEKEND. SHOULD BEGIN TO SEE SOME MOISTURE RETURN LATE FRIDAY AND SATURDAY AS SOUTHERLY WINDS INCREASE...LIKELY SOME LOW CLOUDS CENTRAL AND EAST SECTIONS. GFS FOR NOW KEEPS SHOWERS EAST OF THE AREA. MAY SEE FRONT INTO AREA ON SUNDAY. PROGRESSIVE NATURE OF SYSTEM LIKELY MEANS A DRY FRONT...AND ONLY SLIGHT COOL-DOWN. BOTH GFS AND PREV ECMWF ADVERTISING BIG PATTERN CHANGE WEDNESDAY OF NEXT WEEK (DEC. 4) WITH CRASHING HEIGHTS OVER THE WESTERN CONUS. IF SOME SEMBLANCE OF THIS PATTERN IS REALIZED...COULD TURN MUCH COLDER AROUND THIS TIME...WITH WINTER WEATHER POSSIBLY MAKING A RETURN. DOES BEAR WATCHING. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 18 43 17 39 23 / 10 0 0 0 0 TULIA 21 42 18 39 23 / 10 0 0 0 0 PLAINVIEW 22 43 20 44 25 / 10 0 0 0 0 LEVELLAND 21 45 20 44 25 / 10 0 0 0 0 LUBBOCK 23 45 22 48 27 / 10 0 0 0 0 DENVER CITY 23 46 23 48 25 / 10 0 0 0 0 BROWNFIELD 23 46 22 48 25 / 10 0 0 0 0 CHILDRESS 23 47 24 45 26 / 10 0 0 0 0 SPUR 26 48 22 48 27 / 10 0 0 0 0 ASPERMONT 25 49 26 48 29 / 10 10 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1235 PM CST SUN NOV 24 2013 .DISCUSSION... 18Z AVIATION DISCUSSION BELOW. && .AVIATION... AN APPROACHING WEAK SHORTWAVE DISTURBANCE IS THE IMPETUS TO A LIGHT RAIN SHIELD THAT WILL BE AFFECTING THE MORE NORTHERN TERMINALS THROUGH 21Z THIS AFTERNOON. VFR OVERCAST THROUGH THE AFTERNOON... LOWERING CEILINGS THIS EVENING INTO MVFR CAT/BORDERLINE IFR FROM 25/09Z INTO SUNRISE. NORTHERN COUNTY MODEL PROFILES ARE TRENDING WARMER...WITH A THIN FREEZING OFF-THE-SURFACE LAYER EARLY MONDAY MORNING. THUS...NO MENTION OF FROZEN PRECIP MIX IN KCLL AND KUTS TAFS AT THIS TIME. A BROAD UPPER LOW OVER ARIZONA WILL ADVANCE INTO THE TEXAS PANHANDLE OVER THE NEXT 24 HOURS. AHEAD OF THIS FEATURE...A DEVELOPING CENTRAL TEXAS SURFACE TROUGH WITH WARMER MOIST MID-LEVEL AIR OVERUNNING COOLER SFC AIR WILL AID IN INITIATING NORTH-TO-SOUTH RAINFALL AS EARLY AS THE PRE-DAWN HOURS. MID-LATE MONDAY MORNING INTO EARLY AFTERNOON IS TIMED TO BE WHEN MANY HUBS EXPERIENCE HIGH IFR/LOW MVFR CONDITIONS WITHIN HEAVIER RAIN EPISODES. 31 && .PREV DISCUSSION... /ISSUED 1118 AM CST SUN NOV 24 2013/ UPDATE... SEE MORNING UPDATE. DISCUSSION... 12Z UPPER AIR DATA SHOWS GREATER SATURATION AT 850 MB AND 700 MB THAT YESTERDAY. A WELL DEFINED S/WV IS ALSO NOTED AT BOTH 850 MB AND 700 MB. THE RAP 13 SHOWS AN AREA OF PRECIP MOVING INTO THE REGION THIS AFTN INTO THIS EVENING BUT THERE IS LAYER OF VERY DRY AIR NEAR THE SURFACE THAT WILL NEED TO BE OVERCOME. THINK CHANCE POPS ARE THE WAY TO GO AND WILL TAPER HIGHER POPS WEST AND LOWER POPS EAST. WINDS HAVE DROPPED OFF AND ALLOWED THE WIND ADVISORY TO EXPIRE. 43 && PREV DISCUSSION... /ISSUED 454 AM CST SUN NOV 24 2013/ DISCUSSION... COLDER AIRMASS CONTINUES TO DEEPEN OVER SE TX FROM NE TO SW. AIRMASS IS BECOMING DRIER AND PERHAPS DRIER THAN PREVIOUSLY FORECASTED BY SHORT RANGE MODELS. MIDNIGHT SFC ANALYSIS HAS 1042MB SFC HIGH OVER THE C PLAINS HEADED INTO THE MIDWEST. DUE TO THE DRIER BOUNDARY LAYER...NOT EXPECTING MUCH IN THE WAY OF PRECIP TODAY WITH LOW/MID LEVEL CLOUD DECK. COLD ADVECTION AND CLOUD COVER WILL KEEP MAX TEMPS IN THE 40S TODAY. UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY SHOW CLOSED UPPER LOW OVER THE DESERT SW. SEEMS THE LOW HAS WEAKEN A TOUCH WITH 500MB HEIGHTS A BIT HIGHER THAN 24 HRS AGO. THAT SAID...LEAD JET STREAK AND SHORT WAVE ARE CAUSING FROZEN PRECIP OVER W TX INTO C TX THIS MORNING. THIS LEAD SHORT WAVE DOES NOT SEEM QUITE AS STRONG AS PREVIOUS MODEL RUNS HAD INDICATED. SEEMS THAT PRECIP OVERNIGHT MAY NOT QUITE AS GREAT AND LARGE SCALE LIFT IS NOT AS STRONG. AS SUCH IT WILL TAKE LONGER FOR THE BOUNDARY LAYER TO MOISTEN THROUGH WET BULB THERMODYNAMICS. DO NOT THINK THE THREAT FOR RAIN/SLEET OR FREEZING RAIN MIX WILL BE THAT HIGH MONDAY MORNING. MODEL SOUNDINGS FROM NAM/GFS STILL SUPPORT MIXED PRECIP TYPE FROM COLLEGE STATION TO CROCKETT BUT THAT MAY BE A BIT MORE OF A STRETCH. LIKELY HAVE ALL RAIN IN THESE AREAS. MIN TEMPS WILL BE TRICKY AS WELL. WILL STICK CLOSER TO COLDER GFS MOS NUMBERS IN FORECAST BUT MAY NEED SOME THERMODYNAMICS TO HELP GET THAT COLD AT THE SURFACE. IF THAT HAPPENS WHILE NO ACCUMULATION IS EXPECTED...IMPACTS WILL BE FOR ELEVATED BRIDGES/OVERPASSES WITH A LIGHT GLAZE IF ANYTHING. ON MONDAY MAIN UPPER LEVEL JET AND UPPER LEVEL LOW BEGIN TO MOVE INTO THE AREA. LARGE SCALE ASCENT WILL ONLY INCREASE WITH LARGE OMEGA AND QUITE A BIT OF Q-VECTOR CONVERGENCE SPREADING OVER THE AREA. ISENTROPIC LIFT OVER STALLED FRONT IN THE GULF WILL ONLY INCREASE DUE TO THE STRONG FORCING. NAM/ECMWF STILL KEEP COASTAL LOW CLOSER TO THE COAST THAN THE GFS. NOTICED SEVERAL ENHANCED RAIN BANDS THAT SET UP OVER THE AREA. CROSS-SECTIONS DO SHOW SOME FRONTOGENETIC FORCING CO-LOCATED WITH AREAS OF POSSIBLE CSI. HI- RES WRF-ARW SHOWS SOME VERY SIMILAR BANDED FEATURES AND WOULD NOT BE SURPRISED IF THERE WERE SOME AREAS OF ENHANCED PRECIP DUE TO BANDING. FORECAST WILL STICK WITH 80/90 POPS ON MONDAY. PRECIP TOTALS AGAIN LOOK TO BE IN THE 1-2 INCH RANGE FOR MONDAY. FEEL MOST AREAS SHOULD BE ABLE TO HANDLE THIS MUCH PRECIP ESPECIALLY OVER 6-12 HRS. THE COASTAL LOW WILL ALSO SUPPORT EASTERLY WINDS TO THE NORTH OF IT WHICH COULD INCREASE TIDE LEVELS. WILL AGAIN NEED TO MONITOR FOR THE POSSIBILITY OF COASTAL FLOODING MON/TUE. FORECASTING WINTER PRECIP FOR THE AREA ON TUESDAY IS NOT VERY STRAIGHT FORWARD. ALL OF THE MODELS STILL HAVE THE UPPER LOW TRACKING DIRECTLY OVER THE AREA. IF ANYTHING MAYBE TRACK A BIT FARTHER SOUTH AS A VORT MAX OVER MEXICO HELPS PULL THE LOW SOUTH MONDAY NIGHT. THE UPPER LOW MAY NOW EVEN BE ABOUT 6 HRS SLOWER TRACKING ACROSS THE AREA. DO THINK THAT UPWARD VERTICAL MOTION WILL BE LARGE OVER THE AREA BUT NOT SURE IF THERE WILL BE ENOUGH MOISTURE FOR THE SYSTEM TO WORK WITH AND IF TEMPS IN THE LOW LEVELS WILL BE COLD ENOUGH FOR FROZEN PRECIP. RIGHT NOW THINK NORTHERN AREAS COULD SEE A RAIN/SLEET MIX FROM BASICALLY COLLEGE STATION TO HUNTSVILLE TO LIVINGSTON. NAM/GFS/ECMWF JUST DO NOT SEEM TO COOL 925/850MB TEMPS ENOUGH TO STRICTLY SUPPORT FROZEN PRECIP LIKE RAIN/SLEET/SNOW MIX. BY 18Z TUE TO 00Z WED THE MID/UPPER LEVELS OF THE ATMOSPHERE DRY OUT ENOUGH SO THAT ONLY PRECIP WILL BE RAIN THAT MAY HAPPEN TO FALL THROUGH A SUB-FREEZING LAYER THICK ENOUGH TO FREEZE. WITH THAT SAID...DO NOT WANT TO UNDER-ESTIMATE THE EFFECTS OF DYNAMICAL LIFT FROM THE UPPER LOW AND ANY WET BULBING THAT MAY OCCUR UNDER THE LOW. MAY NEED TO MONITOR FURTHER BUT COULD SEE THE FROZEN PRECIP LINE DROP FARTHER SOUTH ESPECIALLY IF THERE IS MORE MOISTURE TO WORK WITH AND IT LOOKS LIKE TEMPS MAY BE COLD ENOUGH. OVERALL THINK ANY FROZEN PRECIP WILL BE LIGHT AND SHOULD NOT ACCUMULATE. MAIN ISSUES MAY STILL BE ELEVATED SURFACES LIKE OVERPASSES. ATMOSPHERE REALLY DRIES OUT 00Z-12Z WED WITH NEXT FRONT PUSHING THROUGH. HIGH PRESSURE THEN BUILDS INTO THE OZARKS WED NIGHT INTO THUR. SHOULD HAVE CLEAR SKIES AND MUCH CALMER WINDS. LOOKS LIKE THANKSGIVING DAY COULD START OUT WITH AN AREA WIDE FREEZE. EVEN FRIDAY MORNING MAY HAVE SOME SPOTS WITH FREEZING TEMPS. BELOW NORMAL TEMPS SHOULD CONTINUE INTO THE WEEKEND WITH RETURN FLOW FINALLY SETTING UP NEXT SATURDAY INTO SUNDAY. 39 && MARINE... STRONG NORTHEAST WINDS CONTINUE THIS MORNING ACROSS THE COASTAL WATERS THIS MORNING AND ADVISORIES WILL CONTINUE FOR ALL WATERS THROUGH MID MORNING. WINDS ALONG THE IMMEDIATE COAST WILL BEGIN TO WEAKEN AND THE BAYS ARE EXPECTED TO FALL BELOW ADVISORY CRITERIA. WINDS ACROSS THE COASTAL WATERS WILL REMAIN ABOVE ADVISORY CRITERIA THROUGH THE DAY TODAY AND ADVISORIES WILL LIKELY NEED TO BE CARRIED EVEN LONGER...PARTICULARLY FOR THE OFFSHORE WATERS WHERE ADVISORY CONDITIONS ARE EXPECTED THROUGH MID WEEK. FORECAST MODELS CONTINUE TO BRING THE UPPER LEVEL LOW FURTHER SOUTH WHICH WILL SHIFT THE COASTAL LOW SOUTH OF OUR MARINE ZONES AND ALLOW FOR NORTHEAST WINDS THROUGH TUESDAY WHICH WILL BECOME NORTHWESTERLY AS THE UPPER LOW MOVES OFF TO OUR EAST. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 32 38 34 45 31 / 60 90 60 30 10 HOUSTON (IAH) 36 42 36 45 34 / 40 90 70 50 10 GALVESTON (GLS) 43 48 41 48 38 / 40 80 80 60 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: MATAGORDA BAY. SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY. SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION FROM 6 PM CST THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM... WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST MONDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...43 AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1118 AM CST SUN NOV 24 2013 .UPDATE... SEE MORNING UPDATE. && .DISCUSSION... 12Z UPPER AIR DATA SHOWS GREATER SATURATION AT 850 MB AND 700 MB THAT YESTERDAY. A WELL DEFINED S/WV IS ALSO NOTED AT BOTH 850 MB AND 700 MB. THE RAP 13 SHOWS AN AREA OF PRECIP MOVING INTO THE REGION THIS AFTN INTO THIS EVENING BUT THERE IS LAYER OF VERY DRY AIR NEAR THE SURFACE THAT WILL NEED TO BE OVERCOME. THINK CHANCE POPS ARE THE WAY TO GO AND WILL TAPER HIGHER POPS WEST AND LOWER POPS EAST. WINDS HAVE DROPPED OFF AND ALLOWED THE WIND ADVISORY TO EXPIRE. 43 && .PREV DISCUSSION... /ISSUED 538 AM CST SUN NOV 24 2013/ DISCUSSION... SEE AVIATION FOR 12Z TAF DISCUSSION. AVIATION... VFR CONDITIONS AREAWIDE THIS MORNING AND THESE SHOULD PERSIST THROUGH MUCH OF THE DAY WITH MID LEVEL OVERCAST. A SHORTWAVE DISTURBANCE APPROACHING FROM THE SOUTHWEST WILL ALLOW FOR A FEW LIGHT SHOWERS ACROSS THE AREA WITH SOME VIRGA DUE TO VERY DRY AIR AT LOW LEVELS. CIGS WILL BEGIN TO FALL OVERNIGHT WITH LIGHT RAIN MOVING IN AS THE MAIN UPPER LEVEL SYSTEM BEGINS TO APPROACH. MODEL SOUNDINGS SUPPORT A POTENTIAL RA/PL MIX FOR CLL EARLY MONDAY MORNING BUT FEEL THIS IS OVERDONE AND PRECIP SHOULD REMAIN AS RAIN. CHANCES FOR WINTRY MIX AT CLL/UTS LOOK BETTER FOR TUESDAY. 38 PREV DISCUSSION... /ISSUED 454 AM CST SUN NOV 24 2013/ DISCUSSION... COLDER AIRMASS CONTINUES TO DEEPEN OVER SE TX FROM NE TO SW. AIRMASS IS BECOMING DRIER AND PERHAPS DRIER THAN PREVIOUSLY FORECASTED BY SHORT RANGE MODELS. MIDNIGHT SFC ANALYSIS HAS 1042MB SFC HIGH OVER THE C PLAINS HEADED INTO THE MIDWEST. DUE TO THE DRIER BOUNDARY LAYER...NOT EXPECTING MUCH IN THE WAY OF PRECIP TODAY WITH LOW/MID LEVEL CLOUD DECK. COLD ADVECTION AND CLOUD COVER WILL KEEP MAX TEMPS IN THE 40S TODAY. UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY SHOW CLOSED UPPER LOW OVER THE DESERT SW. SEEMS THE LOW HAS WEAKEN A TOUCH WITH 500MB HEIGHTS A BIT HIGHER THAN 24 HRS AGO. THAT SAID...LEAD JET STREAK AND SHORT WAVE ARE CAUSING FROZEN PRECIP OVER W TX INTO C TX THIS MORNING. THIS LEAD SHORT WAVE DOES NOT SEEM QUITE AS STRONG AS PREVIOUS MODEL RUNS HAD INDICATED. SEEMS THAT PRECIP OVERNIGHT MAY NOT QUITE AS GREAT AND LARGE SCALE LIFT IS NOT AS STRONG. AS SUCH IT WILL TAKE LONGER FOR THE BOUNDARY LAYER TO MOISTEN THROUGH WET BULB THERMODYNAMICS. DO NOT THINK THE THREAT FOR RAIN/SLEET OR FREEZING RAIN MIX WILL BE THAT HIGH MONDAY MORNING. MODEL SOUNDINGS FROM NAM/GFS STILL SUPPORT MIXED PRECIP TYPE FROM COLLEGE STATION TO CROCKETT BUT THAT MAY BE A BIT MORE OF A STRETCH. LIKELY HAVE ALL RAIN IN THESE AREAS. MIN TEMPS WILL BE TRICKY AS WELL. WILL STICK CLOSER TO COLDER GFS MOS NUMBERS IN FORECAST BUT MAY NEED SOME THERMODYNAMICS TO HELP GET THAT COLD AT THE SURFACE. IF THAT HAPPENS WHILE NO ACCUMULATION IS EXPECTED...IMPACTS WILL BE FOR ELEVATED BRIDGES/OVERPASSES WITH A LIGHT GLAZE IF ANYTHING. ON MONDAY MAIN UPPER LEVEL JET AND UPPER LEVEL LOW BEGIN TO MOVE INTO THE AREA. LARGE SCALE ASCENT WILL ONLY INCREASE WITH LARGE OMEGA AND QUITE A BIT OF Q-VECTOR CONVERGENCE SPREADING OVER THE AREA. ISENTROPIC LIFT OVER STALLED FRONT IN THE GULF WILL ONLY INCREASE DUE TO THE STRONG FORCING. NAM/ECMWF STILL KEEP COASTAL LOW CLOSER TO THE COAST THAN THE GFS. NOTICED SEVERAL ENHANCED RAIN BANDS THAT SET UP OVER THE AREA. CROSS-SECTIONS DO SHOW SOME FRONTOGENETIC FORCING CO-LOCATED WITH AREAS OF POSSIBLE CSI. HI- RES WRF-ARW SHOWS SOME VERY SIMILAR BANDED FEATURES AND WOULD NOT BE SURPRISED IF THERE WERE SOME AREAS OF ENHANCED PRECIP DUE TO BANDING. FORECAST WILL STICK WITH 80/90 POPS ON MONDAY. PRECIP TOTALS AGAIN LOOK TO BE IN THE 1-2 INCH RANGE FOR MONDAY. FEEL MOST AREAS SHOULD BE ABLE TO HANDLE THIS MUCH PRECIP ESPECIALLY OVER 6-12 HRS. THE COASTAL LOW WILL ALSO SUPPORT EASTERLY WINDS TO THE NORTH OF IT WHICH COULD INCREASE TIDE LEVELS. WILL AGAIN NEED TO MONITOR FOR THE POSSIBILITY OF COASTAL FLOODING MON/TUE. FORECASTING WINTER PRECIP FOR THE AREA ON TUESDAY IS NOT VERY STRAIGHT FORWARD. ALL OF THE MODELS STILL HAVE THE UPPER LOW TRACKING DIRECTLY OVER THE AREA. IF ANYTHING MAYBE TRACK A BIT FARTHER SOUTH AS A VORT MAX OVER MEXICO HELPS PULL THE LOW SOUTH MONDAY NIGHT. THE UPPER LOW MAY NOW EVEN BE ABOUT 6 HRS SLOWER TRACKING ACROSS THE AREA. DO THINK THAT UPWARD VERTICAL MOTION WILL BE LARGE OVER THE AREA BUT NOT SURE IF THERE WILL BE ENOUGH MOISTURE FOR THE SYSTEM TO WORK WITH AND IF TEMPS IN THE LOW LEVELS WILL BE COLD ENOUGH FOR FROZEN PRECIP. RIGHT NOW THINK NORTHERN AREAS COULD SEE A RAIN/SLEET MIX FROM BASICALLY COLLEGE STATION TO HUNTSVILLE TO LIVINGSTON. NAM/GFS/ECMWF JUST DO NOT SEEM TO COOL 925/850MB TEMPS ENOUGH TO STRICTLY SUPPORT FROZEN PRECIP LIKE RAIN/SLEET/SNOW MIX. BY 18Z TUE TO 00Z WED THE MID/UPPER LEVELS OF THE ATMOSPHERE DRY OUT ENOUGH SO THAT ONLY PRECIP WILL BE RAIN THAT MAY HAPPEN TO FALL THROUGH A SUB-FREEZING LAYER THICK ENOUGH TO FREEZE. WITH THAT SAID...DO NOT WANT TO UNDER-ESTIMATE THE EFFECTS OF DYNAMICAL LIFT FROM THE UPPER LOW AND ANY WET BULBING THAT MAY OCCUR UNDER THE LOW. MAY NEED TO MONITOR FURTHER BUT COULD SEE THE FROZEN PRECIP LINE DROP FARTHER SOUTH ESPECIALLY IF THERE IS MORE MOISTURE TO WORK WITH AND IT LOOKS LIKE TEMPS MAY BE COLD ENOUGH. OVERALL THINK ANY FROZEN PRECIP WILL BE LIGHT AND SHOULD NOT ACCUMULATE. MAIN ISSUES MAY STILL BE ELEVATED SURFACES LIKE OVERPASSES. ATMOSPHERE REALLY DRIES OUT 00Z-12Z WED WITH NEXT FRONT PUSHING THROUGH. HIGH PRESSURE THEN BUILDS INTO THE OZARKS WED NIGHT INTO THUR. SHOULD HAVE CLEAR SKIES AND MUCH CALMER WINDS. LOOKS LIKE THANKSGIVING DAY COULD START OUT WITH AN AREA WIDE FREEZE. EVEN FRIDAY MORNING MAY HAVE SOME SPOTS WITH FREEZING TEMPS. BELOW NORMAL TEMPS SHOULD CONTINUE INTO THE WEEKEND WITH RETURN FLOW FINALLY SETTING UP NEXT SATURDAY INTO SUNDAY. 39 MARINE... STRONG NORTHEAST WINDS CONTINUE THIS MORNING ACROSS THE COASTAL WATERS THIS MORNING AND ADVISORIES WILL CONTINUE FOR ALL WATERS THROUGH MID MORNING. WINDS ALONG THE IMMEDIATE COAST WILL BEGIN TO WEAKEN AND THE BAYS ARE EXPECTED TO FALL BELOW ADVISORY CRITERIA. WINDS ACROSS THE COASTAL WATERS WILL REMAIN ABOVE ADVISORY CRITERIA THROUGH THE DAY TODAY AND ADVISORIES WILL LIKELY NEED TO BE CARRIED EVEN LONGER...PARTICULARLY FOR THE OFFSHORE WATERS WHERE ADVISORY CONDITIONS ARE EXPECTED THROUGH MID WEEK. FORECAST MODELS CONTINUE TO BRING THE UPPER LEVEL LOW FURTHER SOUTH WHICH WILL SHIFT THE COASTAL LOW SOUTH OF OUR MARINE ZONES AND ALLOW FOR NORTHEAST WINDS THROUGH TUESDAY WHICH WILL BECOME NORTHWESTERLY AS THE UPPER LOW MOVES OFF TO OUR EAST. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 43 32 38 34 45 / 40 60 90 60 30 HOUSTON (IAH) 47 36 42 36 45 / 20 40 90 70 50 GALVESTON (GLS) 52 43 48 41 48 / 20 40 80 80 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: MATAGORDA BAY. SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY. SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION FROM 6 PM CST THIS EVENING THROUGH MONDAY AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM... WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 6 PM CST MONDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...43
AREA FORECAST DISCUSSION...UPDATED
NWS BLACKSBURG VA
1049 PM EST MON NOV 25 2013 .SYNOPSIS... STORM SYSTEM WILL MOVE FROM THE GULF COAST TONIGHT INTO EASTERN NC/VA BY WEDNESDAY MORNING...AND FINALLY NORTH INTO QUEBEC BY WED NIGHT. THIS SYSTEM WILL BRING A POTPOURRI OF WEATHER THROUGH WED NIGHT. HIGH PRESSURE ENTERS FROM THE SOUTHWEST BY THURSDAY...AND STICKS AROUND INTO SATURDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 1045 PM EST MONDAY... QUICK UPDATE TO START THE ADVISORY RIGHT NOW OVER THE WEST SINCE GETTING REPORTS OF SNOW ACCUMULATING ON ROADS ACROSS THE FAR SW. LEAVING THE REMAINDER FROM ALONG THE BLUE RIDGE EAST STARTING AT 2 AM. AS OF 825 PM EST MONDAY... MID/LOW LEVEL DRY AIR PER EVENING SOUNDINGS AND LATEST OBS HAS CONTINUED TO KEEP PRECIP FARTHER TO THE WEST THIS EVENING WITH MOST PRECIP ON RADAR ALOFT AND JUST GOING TO SLOWLY MOISTEN THE COLUMN ATTM. IN ADDITION THE LOW LEVEL FLOW REMAINS RATHER WEAK AND SW JUST ABOVE THE SURFACE MAKING FOR LIMITED ISENTROPIC LIFT AS THE BEST JET SUPPORT INCLUDING AXIS OF HIGHER DEWPOINTS LINGERS ACROSS THE TN VALLEY. BOTH THE LATEST RAP AND HRRR HAVE DELAYED THE ONSET OF SIGNIFICANT PRECIP UNTIL AFTER MIDNIGHT FOR THE MOST PART WEST AND UNTIL THE EARLY MORNING HOURS OUT EAST. SINCE THIS LOOKS IN LINE WITH THE LATEST TRENDS...HAVE DELAYED ONSET OF POPS ACROSS THE REGION FOR COUPLE HOURS BEFORE THINGS REALLY MOISTEN AND PRECIP QUICKLY INCREASES ESPCLY BLUE RIDGE AND ACROSS THE SOUTH AFTER MIDNIGHT. EVENING RAOBS AND SURFACE OBS INDICATE STILL LOTS OF ROOM FOR WET BULB COOLING ALTHOUGH TREND OUT WEST HAS BEEN FOR DEWPOINTS TO RISE WITHOUT MUCH COOLING AS PRECIP EVAPORATES BEFORE REACHING THE SURFACE. THIS SUPPORTS KEEPING A MIXED BAG BUT A LITTLE MORE SNOW WEST AT THE ONSET WITH SOME CHANCE OF SNOW/SLEET EAST THEN MOSTLY FZRA/SLEET. ADJUSTED TEMPS DOWN SOME FOR CURRENT READINGS WITH MOST LIKELY NOT DROPPING TOO MUCH MORE UNTIL HEAVIER PRECIP ARRIVES. MAIN ADJUST TO HEADLINES WAS TO EXTEND THE GOING ADVISORY LONGER INTO THE AFTERNOON ON TUESDAY FOR AMHERST/BOTETOURT COUNTIES GIVEN FORECAST SOUNDINGS SHOWING TEMPS UNABLE TO GET MUCH ABOVE FREEZING UNTIL LATE IN THE DAY. THIS MAY ALSO BE THE CASE ON THE NORTH SIDE OF HIGHWAY 460 IN ROANOKE AND MONTGOMERY COUNTIES BUT HELD THOSE AREAS AT A NOON EXPIRATION FOR NOW GIVEN POTENTIAL FOR THAT AREA TO SEE WARMING FROM HEAVIER RAINFALL THROUGH THE WARM LAYER SOONER. PREVIOUS DISCUSSION AS OF 250 PM EST MONDAY... DURING THIS TIME PERIOD WILL BE DEALING WITH NUISANCE WINTER WX WHERE PRECIP ARRIVES INTO THE NC MTNS/FAR SW VA BEFORE MIDNIGHT OVERSPREADING THE REGION BY DAWN. SUNSHINE CAME OUT TODAY OVER MOST OF THE AREA ALLOWING TEMPS TO CLIMB ABOVE FREEZING AND AROUND 40 IN SOUTHSIDE VA/FAR SW VA. DEWPOINTS HOWEVER ARE TANKED IN THE SINGLE DIGITS. HENCE LIES THE PROBLEM TONIGHT. UPSTREAM CLOUDS ALREADY POURING BACK IN AND THIS MAY HELP IN TERMS OF NOT ALLOWING TEMPS TO DROP TOO FAR AFTER SUNSET AS CLOUDS ACT AS A BLANKET. THEN...AS THE PRECIP ARRIVES...GIVEN THE DRY AIR IT MAY TAKE AN HOUR OR TWO TO SATURATE THE LOW LVLS BUT ONCE IT DOES...THE TEMP/DEWPOINT PROFILE WILL HEAD TOWARD CRITICAL LEVELS FOR WINTER PRECIP. AT THE ONSET THE TEMPS SHOULD BE COLD ENOUGH FOR SLEET OR SNOW THEN CHANGE QUICKLY TO FREEZING RAIN AS STRONG SOUTH TO SOUTHWEST FLOW BRINGS A WARM NOSE INTO THE MTNS AFTER MIDNIGHT AND REACHING OUR NRN CWA BY MID MORNING. WITH INSITU WEDGE AND SFC WET BULBING TO AT OR BELOW ZERO WITH WARM NOSE...FREEZING RAIN WILL BECOME AN ISSUE. GROUND HAS TURNED COLDER AS EVIDENCE BY SOIL TEMPS IN THE LOWER TO MID 30S. THERE WILL BE A LIGHT ACCUMULATION OF SLEET OR SNOW AT THE ONSET...LESS THAN AN INCH...THEN QUICKLY CHANGING TO FZRA WITH GLAZING EXPECTED ALONG TREE/POWERLINES AND METAL OBJECTS FIRST THEN BRIDGES/OVERPASSES. BASED ON RAINFALL RATE AND WARM AIR ALOFT THE ACCRETION OF ICE WILL BE IN A 2-4 HOUR WINDOW AS THE BETTER LIFT TAKES PLACE AFTER 12Z...ALLOWING THE RATES TO INCREASE AND DRAG DOWN WARMER AIR. MODERATE TO HEAVIER RAINFALL USUALLY DOES NOT STICK TO ROADS VERY WELL WHEN SFC TEMPS ARE EXPECTED TO BE NEAR FREEZING. NEED MORE LIKE MID TO UPPER 20S OR LOWER. STILL THERE SEEMS TO BE ENOUGH EVIDENCE THAT MOST OF OUR CWA WILL GET AT LEAST A TRACE OF ICE WITH HIGHER AMOUNTS ALONG THE BLUE RIDGE FROM BOONE/BLOWING ROCK NORTH TO BUENA VISTA/AMHERST. ALSO THE ALLEGHANY HIGHLAND SHOULD SEE UP TO 2/10S. IT ONLY TAKES A TRACE OF ICE TO CAUSE TRAVEL PROBLEMS. BASED ON THIS AND COLLABORATION WITH SURROUNDING NWS OFFICES...WE HAVE A WINTER WX ADVISORY OUT FOR THE ENTIRE CWA FOR TONIGHT-MIDDAY/AFTERNOON TUESDAY...ENDING EARLIER IN THE SOUTH. TEMPS THIS EVENING WILL START FALLING SLOWLY THEN DROP A LITTLE MORE ONCE PRECIP ARRIVES ALOFT LEADING TO EVAP COOLING. LOOKING AT LOWS FROM THE UPPER 20S TO AROUND 30...THEN WARMING GRADUALLY TO ABOVE FREEZING DURING THE DAY TUESDAY...FIRST IN THE FAR SW VA/SRN WV AREA OUTSIDE THE WEDGE AND INTO WRN NC MTNS ALONG THE TN BORDER...THEN SOUTHSIDE VA/NW NC PIEDMONT EXPANDING NORTHWARD BY AFTERNOON TO THE NRN BLUE RIDGE. COULD BE A DEAL WHERE SOME VALLEYS ACROSS BATH/ROCKBRIDGE/AMHERST TAKE INTO TUE EVENING...BUT THINK THE WARMER RAIN AND HIGHER RATES TO BRING IT UP. FOR MOST OF US...THE ICE WILL BE MELTED AND GONE BY MIDDAY/EARLY AFTERNOON WITH HIGHS EXPECTED TO BE IN THE MID TO UPPER 30S SOUTH...TO LOWER 30S NORTH. BUT WILL BE DEALING WITH MODERATE TO HEAVY AT TIMES COLD NOVEMBER RAINS. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 340 PM EST MONDAY... GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE NORTHERN AND SOUTHERN BEGINNING TO PHASE TUESDAY NIGHT AND BECOME ONE SYSTEM WEDNESDAY. THE UPPER LEVEL LOW TRACKING ALONG THE GULF COAST WILL OPEN OVER THE TENNESSEE VALLEY AND MERGE WITH THE NORTHERN STREAM TROUGH ENTERING THE OHIO VALLEY BY WEDNESDAY MORNING. THE SURFACE LOW PRESSURE OVER GEORGIA ON TUESDAY EVENING WILL TRACK NORTHEAST ALONG THE LEE SIDE OF THE APPALACHIAN MOUNTAINS EARLY WEDNESDAY MORNING. AS THE NORTHERN STREAM TROUGH BECOMES DOMINATE...A SECONDARY SURFACE LOW IS EXPECTED TO DEVELOP OVER THE VIRGINIA PIEDMONT TUESDAY NIGHT...THEN LIFT TO NEW ENGLAND ON WEDNESDAY. BY WEDNESDAY EVENING...THE SFC LOW WILL BE LOCATED OVER MAINE WITH TRAILING COLD FRONT PUSHING INTO THE ATLANTIC OCEAN. HIGH PRESSURE WILL BE BUILDING ACROSS OUR REGION WEDNESDAY NIGHT INTO THURSDAY. THE RAIN MAY BE HEAVY AT TIMES TUESDAY AFTERNOON INTO WEDNESDAY MORNING. JET DYNAMICS AND LIFT ASSOCIATED WITH PASSING SURFACE AND SHORTWAVES WILL BRING HIGH RAINFALL RATES TO THE AREA. COLDER AIR WILL PUSH INTO OUR REGION TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN WILL TRANSITION TO SNOW STARTING ALONG THE HIGHER ELEVATION THEN ACROSS THE REST ON WEDNESDAY. MOISTURE WILL PULL OUT OF MOST OF THE AREA WEDNESDAY EVENING INTO WEDNESDAY NIGHT. NORTHWEST UPSLOPE SNOW SHOWERS AND SNOW FLURRIES WILL CONTINUE INTO WEDNESDAY NIGHT INTO THURSDAY. POTENTIAL STORM TOTAL SNOW FOR THE MOUNTAINS WILL LIKELY RANGE FROM 1-4 INCHES TUESDAY NIGHT INTO WEDNESDAY...WITH UPWARDS OF 4 TO 6 INCHES ON WESTERN SLOPES TUESDAY NIGHT INTO WEDNESDAY NIGHT. LIGHTER AMOUNTS OF SNOW EXPECTED GENERALLY LESS THAN INCH IN THE EAST. INCREASING WINDS WILL ACCOMPANY THE UPSLOPE SNOW SHOWERS. STRONG PRESSURE RISES AND COLD AIR ADVECTION ALONG WITH A 45-55KT CROSS BARRIER JET WILL BRING SUSTAIN WINDS OF 20-30 MPH GUSTING TO AROUND 50 MPH FOR COUNTIES ALONG THE BLUE RIDGE...PARTICULARLY THE NORTH CAROLINA HIGH COUNTY AND GRAYSON HIGHLANDS. WIND SPEED WILL BE CLOSE TO ADVISORY LEVELS. WILL HOLD OFF ON ISSUING HEADLINES FOR SNOW AND WINDS FOR NOW TO AVOID CONFUSION WITH ONGOING EVENT. ONE SET OF HEADLINES WILL BE REPLACED BY ANOTHER SET EVERY 6-12 HOURS. PLAN TO HIGHLIGHT THE POTENTIAL IN HWO. AS THIS SYSTEM DEVELOPS AND MATURES OVER THE REGION...EVERYONE SHOULD BE PREPARED FOR RAPIDLY CHANGING CONDITIONS...ESPECIALLY IF YOU ARE TRAVELING ALONG THE EAST COAST THIS WEEK. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 1245 PM EDT MONDAY... LARGE SCALE PATTERN TRANSITIONS TO ZONAL FLOW WITH SURFACE HIGH PRESSURE IN CONTROL THROUGH THE WEEKEND. THIS RESULTS IN SLOWLY MODERATING TEMPERATURES...YET SHOULD REMAIN BELOW SEASONABLE AVERAGES EVEN BY SUNDAY. ALSO THINKING HIGHER CLOUDS WILL BECOME MORE PREVALENT BY SUNDAY WHICH WOULD KEEP HIGHS DOWN SOMEWHAT. LONG TERM MODELS GENERALLY IN AGREEMENT THAT NEXT WEATHER SYSTEM WILL MATERIALIZE IN THE SOUTHERN PLAINS LATE SUNDAY AND THEN QUICKLY APPROACHING THE SOUTHERN APPALACHIANS FROM THE SOUTHWEST ON MONDAY. RIGHT NOW THE 00Z ECWMF IS A LITTLE FASTER THAN THE 12Z GFS AND GIVEN THE GENERALLY ZONAL FLOW PATTERN THIS FASTER IDEA IS FAVORED...ESPECIALLY AS A STRONGER SYSTEM DIGS INTO THE WESTERN U.S. AND EJECTS THIS WAVE OUT ACROSS THE PLAINS AND TOWARDS THE APPALACHIANS. THE HIGH PRESSURE WILL BE WEAKENING AND RETREATING AS THIS SYSTEM APPROACHES BY EARLY MONDAY BUT AIRMASS APPEARS THAT IT WILL MODERATE ENOUGH SO THAT PRECIP TYPE REMAINS JUST RAIN. HOWEVER IT WILL BE WORTH KEEPING AN EYE ON THE TIMING OF PRECIP ARRIVAL AND STRENGTH OF LINGERING HIGH...AS WELL AS HOW LOW INITIAL WET BULB TEMPERATURES ARE WHEN PRECIP ARRIVES. CANT RULE OUT SOME POCKETS OF FREEZING RAIN IF THIS COMES IN OVERNIGHT...BUT AT THIS POINT STILL A LONG WAY OFF. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... AS OF 545 PM EST MONDAY... VFR CONDITIONS THIS EVENING TO LOWER TO MVFR/IFR TONIGHT AS MIXED PRECIP MOVES IN FROM THE SW. THUS LOOKING AT DETERIORATING FLYING WEATHER LATER THIS EVENING WITH WIDESPREAD LOW CIGS AND AT LEAST MVFR VSBYS OVER THE WEST BY DAYBREAK TUESDAY. SOME SNOW/SLEET POSSIBLE AT THE ONSET AT BLF/ROA/BCB/LWB SHOULD CHANGE QUICKLY TO FZRA...WHILE LYH STARTS AS FZRA WITH PERHAPS A BIT OF PL. DAN WILL BE BORDERLINE ON FZRA BUT TEMPS SHOULD BE HUGGING 32-33F AT THE SFC SO INCLUDED A HOUR OR TWO OF -FZRA THERE EARLY TUESDAY. WARM NOSE ALOFT TO CHANGE FZRA TO RAIN AT ALL SITES TUESDAY AFTERNOON ALTHOUGH SPOTS LIKE KLWB/KLYH MAY KEEP -FZRA INTO MID OR LATE AFTERNOON. RAIN BECOMES HEAVY AT TIMES TUESDAY AFTERNOON ESPECIALLY AT BCB/ROA/LYH/DAN. WILL EXPECT TO SEE FLUCTUATIONS IN CIGS/VSBYS BASED ON RAINFALL RATES BUT OVERALL SHOULD BE IFR TO LIFR WITH MOUNTAIN OBSCURATIONS LIKELY. WITH THE STRONG SE FLOW ABOVE THE SURFACE WILL ALSO BE SEEING LLWS POTENTIAL AT ALL LOCATIONS THROUGH THE DAY TUESDAY AS LATEST SOUNDINGS INDICATE 35-45 KTS JUST ABOVE THE SURFACE ESPCLY IN THE AFTERNOON. THEREFORE INCLUDED LLWS AT MOST SPOTS FOR STRONG SOUTH TO SE FLOW DEVELOPING RIGHT AFTER SUNRISE ON TUESDAY. MODERATE TO HEAVY RAINFALL CONTINUES TUESDAY NIGHT WITH LOCATIONS ACROSS SE WVA TRANSITIONING BACK TO SNOW BY EARLY WEDNESDAY. THIS WILL KEEP LOW IFR/LIFR CIGS AND MVFR TO IFR VSBYS GOING TUESDAY NIGHT AS THE CORE OF THE LOW PRESSURE SYSTEM TRACKS ACROSS THE AREA. RAIN CHANGES TO A SIGNIFICANT UPSLOPE EVENT BY WED WITH PERHAPS A TRAILING DEFORMATION BAND OF SNOW WORKING EAST TOWARD THE BLUE RIDGE WED MORNING. THIS MAY RESULT IN A FEW INCHES OF SNOW ACCUMULATION AROUND KBLF/KLWB AND POSSIBLY A LIGHT AMOUNT EAST TO KBCB. WIND WILL ALSO BECOME AN ISSUE ACROSS THE MOUNTAINS WITH NW WIND GUSTS TO 45 KTS OR MORE WED WITH A SIGNIFICANT COASTAL LOW MOVING ACROSS COASTAL NEW ENGLAND. RAPID IMPROVEMENT WILL OCCUR ON THURSDAY AS THE STORM SYSTEM PULLS AWAY AND DRIER AIR WORKS IN...RESULTING IN WIDESPREAD VFR CONDITIONS. VFR THEN CONTINUES UNDER HIGH PRESSURE FOR FRIDAY THROUGH SATURDAY. && .HYDROLOGY... AS OF NOON EST MONDAY... MODEL CONSENSUS AND HPC GUIDANCE GENERALLY IN THE 2 TO 3 INCH RANGE OF LIQUID QPF FOR THE IMPENDING STORM EVENT ALTHOUGH SOME SREF ENSEMBLE MEMBERS SHOWING OVER 4 INCHES BY ABOUT 12Z WEDNESDAY THE 27TH. QUESTION IS WHAT IMPACT THE RUNOFF FROM THIS WILL HAVE ON AREA STREAMS AND RIVERS. POINT ONE IS THAT RIVERS ARE STARTING OFF AT VERY LOW LEVELS ESPECIALLY ACROSS THE LOWER PORTIONS OF OUR RIVER BASINS...ACROSS THE PIEDMONT. USGS DAILY STREAMFLOW PERCENTILES AS OF THIS MORNING ARE SHOWING NEARLY ALL PIEDMONT RIVER AND STREAM LOCATIONS RUNNING AT FLOWS BELOW THE 25TH PERCENTILE FOR THE DATE AND SOME BELOW THE 10TH PERCENTILE. THIS ALSO HOLDS TRUE FOR MUCH OF THE UPPER JAMES RIVER BASIN. 60-DAY RAINFALL DEFICITS HAVE BECOME QUITE SIGNIFICANT...REACHING 4 TO 6 INCHES IN MANY OF THESE BASINS OR AROUND 25 PERCENT OF NORMAL. DETERMINISTIC RIVER FORECASTS ISSUED THIS MORNING BY THE FOUR RFCS SERVING THE BLACKSBURG HYDRO SERVICE AREA INCLUDE 48 HOURS OF QPF THROUGH 12Z WEDNESDAY OF GENERALLY 2 TO 2.5 INCHES. AT OF THIS PACKAGE NO RIVERS ARE FORECAST TO REACH FLOOD STAGE OR EVEN ACTION STAGE (GENERALLY A FEW FEET BELOW FLOOD STAGE) ALTHOUGH SEVERAL COME CLOSE...INCLUDING THE NORTH FORK HOLSTON RIVER AT SALTVILLE AND GREENBRIER RIVER AT ALDERSON. THAT SAID HYDROLOGIC MODELS TEND TO HAVE SOME DIFFICULTY AFTER EXTENDED DRY PERIODS IN HANDLING RUNOFF WHICH IS GENERALLY MUCH MORE EFFICIENT IN THE COOL SEASON. HENCE...THE RESPONSE ON RIVERS REMAINS SOMEWHAT UNCERTAIN BUT NOT ENOUGH CONFIDENCE TO ISSUE A FLOOD WATCH. NOT EXPECTING MUCH IF ANY CONVECTION WITH THIS STORM SO RAINFALL RATES SHOULD REMAIN MODEST..IN THE 0.10 TO 0.25 INCH PER HOUR RANGE. BUT HIGHER RAINFALL RATES IN ANY ELEVATED STORMS THAT ARE ABLE TO DEVELOP COULD LEAD TO LOCALIZED RUNOFF PROBLEMS. THESE COULD BE HANDLED WITH SHORT-FUSE HYDROLOGIC PRODUCTS..FLOOD ADVISORIES OR EVEN FLASH FLOOD WARNINGS BUT THE LIKELIHOOD AT THIS POINT IS QUITE LOW FOR THIS TO OCCUR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM EST TUESDAY FOR VAZ018>020-023-024-035. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ007- 009>017. WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR VAZ022-032>034-043>047-058-059. NC...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NCZ001-002- 018. WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ003>006-019-020. WV...WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM EST TUESDAY FOR WVZ045. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR WVZ042>044. && $$ SYNOPSIS...RAB/WP NEAR TERM...JH/WP SHORT TERM...KK LONG TERM...SK AVIATION...JH/RAB/WP HYDROLOGY...PC
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
905 PM EST MON NOV 25 2013 .SYNOPSIS... STORM SYSTEM WILL MOVE FROM THE GULF COAST TONIGHT INTO EASTERN NC/VA BY WEDNESDAY MORNING...AND FINALLY NORTH INTO QUEBEC BY WED NIGHT. THIS SYSTEM WILL BRING A POTPOURRI OF WEATHER THROUGH WED NIGHT. HIGH PRESSURE ENTERS FROM THE SOUTHWEST BY THURSDAY...AND STICKS AROUND INTO SATURDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 825 PM EST MONDAY... MID/LOW LEVEL DRY AIR PER EVENING SOUNDINGS AND LATEST OBS HAS CONTINUED TO KEEP PRECIP FARTHER TO THE WEST THIS EVENING WITH MOST PRECIP ON RADAR ALOFT AND JUST GOING TO SLOWLY MOISTEN THE COLUMN ATTM. IN ADDITION THE LOW LEVEL FLOW REMAINS RATHER WEAK AND SW JUST ABOVE THE SURFACE MAKING FOR LIMITED ISENTROPIC LIFT AS THE BEST JET SUPPORT INCLUDING AXIS OF HIGHER DEWPOINTS LINGERS ACROSS THE TN VALLEY. BOTH THE LATEST RAP AND HRRR HAVE DELAYED THE ONSET OF SIGNIFICANT PRECIP UNTIL AFTER MIDNIGHT FOR THE MOST PART WEST AND UNTIL THE EARLY MORNING HOURS OUT EAST. SINCE THIS LOOKS IN LINE WITH THE LATEST TRENDS...HAVE DELAYED ONSET OF POPS ACROSS THE REGION FOR COUPLE HOURS BEFORE THINGS REALLY MOISTEN AND PRECIP QUICKLY INCREASES ESPCLY BLUE RIDGE AND ACROSS THE SOUTH AFTER MIDNIGHT. EVENING RAOBS AND SURFACE OBS INDICATE STILL LOTS OF ROOM FOR WET BULB COOLING ALTHOUGH TREND OUT WEST HAS BEEN FOR DEWPOINTS TO RISE WITHOUT MUCH COOLING AS PRECIP EVAPORATES BEFORE REACHING THE SURFACE. THIS SUPPORTS KEEPING A MIXED BAG BUT A LITTLE MORE SNOW WEST AT THE ONSET WITH SOME CHANCE OF SNOW/SLEET EAST THEN MOSTLY FZRA/SLEET. ADJUSTED TEMPS DOWN SOME FOR CURRENT READINGS WITH MOST LIKELY NOT DROPPING TOO MUCH MORE UNTIL HEAVIER PRECIP ARRIVES. MAIN ADJUST TO HEADLINES WAS TO EXTEND THE GOING ADVISORY LONGER INTO THE AFTERNOON ON TUESDAY FOR AMHERST/BOTETOURT COUNTIES GIVEN FORECAST SOUNDINGS SHOWING TEMPS UNABLE TO GET MUCH ABOVE FREEZING UNTIL LATE IN THE DAY. THIS MAY ALSO BE THE CASE ON THE NORTH SIDE OF HIGHWAY 460 IN ROANOKE AND MONTGOMERY COUNTIES BUT HELD THOSE AREAS AT A NOON EXPIRATION FOR NOW GIVEN POTENTIAL FOR THAT AREA TO SEE WARMING FROM HEAVIER RAINFALL THROUGH THE WARM LAYER SOONER. PREVIOUS DISCUSSION AS OF 250 PM EST MONDAY... DURING THIS TIME PERIOD WILL BE DEALING WITH NUISANCE WINTER WX WHERE PRECIP ARRIVES INTO THE NC MTNS/FAR SW VA BEFORE MIDNIGHT OVERSPREADING THE REGION BY DAWN. SUNSHINE CAME OUT TODAY OVER MOST OF THE AREA ALLOWING TEMPS TO CLIMB ABOVE FREEZING AND AROUND 40 IN SOUTHSIDE VA/FAR SW VA. DEWPOINTS HOWEVER ARE TANKED IN THE SINGLE DIGITS. HENCE LIES THE PROBLEM TONIGHT. UPSTREAM CLOUDS ALREADY POURING BACK IN AND THIS MAY HELP IN TERMS OF NOT ALLOWING TEMPS TO DROP TOO FAR AFTER SUNSET AS CLOUDS ACT AS A BLANKET. THEN...AS THE PRECIP ARRIVES...GIVEN THE DRY AIR IT MAY TAKE AN HOUR OR TWO TO SATURATE THE LOW LVLS BUT ONCE IT DOES...THE TEMP/DEWPOINT PROFILE WILL HEAD TOWARD CRITICAL LEVELS FOR WINTER PRECIP. AT THE ONSET THE TEMPS SHOULD BE COLD ENOUGH FOR SLEET OR SNOW THEN CHANGE QUICKLY TO FREEZING RAIN AS STRONG SOUTH TO SOUTHWEST FLOW BRINGS A WARM NOSE INTO THE MTNS AFTER MIDNIGHT AND REACHING OUR NRN CWA BY MID MORNING. WITH INSITU WEDGE AND SFC WET BULBING TO AT OR BELOW ZERO WITH WARM NOSE...FREEZING RAIN WILL BECOME AN ISSUE. GROUND HAS TURNED COLDER AS EVIDENCE BY SOIL TEMPS IN THE LOWER TO MID 30S. THERE WILL BE A LIGHT ACCUMULATION OF SLEET OR SNOW AT THE ONSET...LESS THAN AN INCH...THEN QUICKLY CHANGING TO FZRA WITH GLAZING EXPECTED ALONG TREE/POWERLINES AND METAL OBJECTS FIRST THEN BRIDGES/OVERPASSES. BASED ON RAINFALL RATE AND WARM AIR ALOFT THE ACCRETION OF ICE WILL BE IN A 2-4 HOUR WINDOW AS THE BETTER LIFT TAKES PLACE AFTER 12Z...ALLOWING THE RATES TO INCREASE AND DRAG DOWN WARMER AIR. MODERATE TO HEAVIER RAINFALL USUALLY DOES NOT STICK TO ROADS VERY WELL WHEN SFC TEMPS ARE EXPECTED TO BE NEAR FREEZING. NEED MORE LIKE MID TO UPPER 20S OR LOWER. STILL THERE SEEMS TO BE ENOUGH EVIDENCE THAT MOST OF OUR CWA WILL GET AT LEAST A TRACE OF ICE WITH HIGHER AMOUNTS ALONG THE BLUE RIDGE FROM BOONE/BLOWING ROCK NORTH TO BUENA VISTA/AMHERST. ALSO THE ALLEGHANY HIGHLAND SHOULD SEE UP TO 2/10S. IT ONLY TAKES A TRACE OF ICE TO CAUSE TRAVEL PROBLEMS. BASED ON THIS AND COLLABORATION WITH SURROUNDING NWS OFFICES...WE HAVE A WINTER WX ADVISORY OUT FOR THE ENTIRE CWA FOR TONIGHT-MIDDAY/AFTERNOON TUESDAY...ENDING EARLIER IN THE SOUTH. TEMPS THIS EVENING WILL START FALLING SLOWLY THEN DROP A LITTLE MORE ONCE PRECIP ARRIVES ALOFT LEADING TO EVAP COOLING. LOOKING AT LOWS FROM THE UPPER 20S TO AROUND 30...THEN WARMING GRADUALLY TO ABOVE FREEZING DURING THE DAY TUESDAY...FIRST IN THE FAR SW VA/SRN WV AREA OUTSIDE THE WEDGE AND INTO WRN NC MTNS ALONG THE TN BORDER...THEN SOUTHSIDE VA/NW NC PIEDMONT EXPANDING NORTHWARD BY AFTERNOON TO THE NRN BLUE RIDGE. COULD BE A DEAL WHERE SOME VALLEYS ACROSS BATH/ROCKBRIDGE/AMHERST TAKE INTO TUE EVENING...BUT THINK THE WARMER RAIN AND HIGHER RATES TO BRING IT UP. FOR MOST OF US...THE ICE WILL BE MELTED AND GONE BY MIDDAY/EARLY AFTERNOON WITH HIGHS EXPECTED TO BE IN THE MID TO UPPER 30S SOUTH...TO LOWER 30S NORTH. BUT WILL BE DEALING WITH MODERATE TO HEAVY AT TIMES COLD NOVEMBER RAINS. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 340 PM EST MONDAY... GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE NORTHERN AND SOUTHERN BEGINNING TO PHASE TUESDAY NIGHT AND BECOME ONE SYSTEM WEDNESDAY. THE UPPER LEVEL LOW TRACKING ALONG THE GULF COAST WILL OPEN OVER THE TENNESSEE VALLEY AND MERGE WITH THE NORTHERN STREAM TROUGH ENTERING THE OHIO VALLEY BY WEDNESDAY MORNING. THE SURFACE LOW PRESSURE OVER GEORGIA ON TUESDAY EVENING WILL TRACK NORTHEAST ALONG THE LEE SIDE OF THE APPALACHIAN MOUNTAINS EARLY WEDNESDAY MORNING. AS THE NORTHERN STREAM TROUGH BECOMES DOMINATE...A SECONDARY SURFACE LOW IS EXPECTED TO DEVELOP OVER THE VIRGINIA PIEDMONT TUESDAY NIGHT...THEN LIFT TO NEW ENGLAND ON WEDNESDAY. BY WEDNESDAY EVENING...THE SFC LOW WILL BE LOCATED OVER MAINE WITH TRAILING COLD FRONT PUSHING INTO THE ATLANTIC OCEAN. HIGH PRESSURE WILL BE BUILDING ACROSS OUR REGION WEDNESDAY NIGHT INTO THURSDAY. THE RAIN MAY BE HEAVY AT TIMES TUESDAY AFTERNOON INTO WEDNESDAY MORNING. JET DYNAMICS AND LIFT ASSOCIATED WITH PASSING SURFACE AND SHORTWAVES WILL BRING HIGH RAINFALL RATES TO THE AREA. COLDER AIR WILL PUSH INTO OUR REGION TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN WILL TRANSITION TO SNOW STARTING ALONG THE HIGHER ELEVATION THEN ACROSS THE REST ON WEDNESDAY. MOISTURE WILL PULL OUT OF MOST OF THE AREA WEDNESDAY EVENING INTO WEDNESDAY NIGHT. NORTHWEST UPSLOPE SNOW SHOWERS AND SNOW FLURRIES WILL CONTINUE INTO WEDNESDAY NIGHT INTO THURSDAY. POTENTIAL STORM TOTAL SNOW FOR THE MOUNTAINS WILL LIKELY RANGE FROM 1-4 INCHES TUESDAY NIGHT INTO WEDNESDAY...WITH UPWARDS OF 4 TO 6 INCHES ON WESTERN SLOPES TUESDAY NIGHT INTO WEDNESDAY NIGHT. LIGHTER AMOUNTS OF SNOW EXPECTED GENERALLY LESS THAN INCH IN THE EAST. INCREASING WINDS WILL ACCOMPANY THE UPSLOPE SNOW SHOWERS. STRONG PRESSURE RISES AND COLD AIR ADVECTION ALONG WITH A 45-55KT CROSS BARRIER JET WILL BRING SUSTAIN WINDS OF 20-30 MPH GUSTING TO AROUND 50 MPH FOR COUNTIES ALONG THE BLUE RIDGE...PARTICULARLY THE NORTH CAROLINA HIGH COUNTY AND GRAYSON HIGHLANDS. WIND SPEED WILL BE CLOSE TO ADVISORY LEVELS. WILL HOLD OFF ON ISSUING HEADLINES FOR SNOW AND WINDS FOR NOW TO AVOID CONFUSION WITH ONGOING EVENT. ONE SET OF HEADLINES WILL BE REPLACED BY ANOTHER SET EVERY 6-12 HOURS. PLAN TO HIGHLIGHT THE POTENTIAL IN HWO. AS THIS SYSTEM DEVELOPS AND MATURES OVER THE REGION...EVERYONE SHOULD BE PREPARED FOR RAPIDLY CHANGING CONDITIONS...ESPECIALLY IF YOU ARE TRAVELING ALONG THE EAST COAST THIS WEEK. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 1245 PM EDT MONDAY... LARGE SCALE PATTERN TRANSITIONS TO ZONAL FLOW WITH SURFACE HIGH PRESSURE IN CONTROL THROUGH THE WEEKEND. THIS RESULTS IN SLOWLY MODERATING TEMPERATURES...YET SHOULD REMAIN BELOW SEASONABLE AVERAGES EVEN BY SUNDAY. ALSO THINKING HIGHER CLOUDS WILL BECOME MORE PREVALENT BY SUNDAY WHICH WOULD KEEP HIGHS DOWN SOMEWHAT. LONG TERM MODELS GENERALLY IN AGREEMENT THAT NEXT WEATHER SYSTEM WILL MATERIALIZE IN THE SOUTHERN PLAINS LATE SUNDAY AND THEN QUICKLY APPROACHING THE SOUTHERN APPALACHIANS FROM THE SOUTHWEST ON MONDAY. RIGHT NOW THE 00Z ECWMF IS A LITTLE FASTER THAN THE 12Z GFS AND GIVEN THE GENERALLY ZONAL FLOW PATTERN THIS FASTER IDEA IS FAVORED...ESPECIALLY AS A STRONGER SYSTEM DIGS INTO THE WESTERN U.S. AND EJECTS THIS WAVE OUT ACROSS THE PLAINS AND TOWARDS THE APPALACHIANS. THE HIGH PRESSURE WILL BE WEAKENING AND RETREATING AS THIS SYSTEM APPROACHES BY EARLY MONDAY BUT AIRMASS APPEARS THAT IT WILL MODERATE ENOUGH SO THAT PRECIP TYPE REMAINS JUST RAIN. HOWEVER IT WILL BE WORTH KEEPING AN EYE ON THE TIMING OF PRECIP ARRIVAL AND STRENGTH OF LINGERING HIGH...AS WELL AS HOW LOW INITIAL WET BULB TEMPERATURES ARE WHEN PRECIP ARRIVES. CANT RULE OUT SOME POCKETS OF FREEZING RAIN IF THIS COMES IN OVERNIGHT...BUT AT THIS POINT STILL A LONG WAY OFF. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... AS OF 545 PM EST MONDAY... VFR CONDITIONS THIS EVENING TO LOWER TO MVFR/IFR TONIGHT AS MIXED PRECIP MOVES IN FROM THE SW. THUS LOOKING AT DETERIORATING FLYING WEATHER LATER THIS EVENING WITH WIDESPREAD LOW CIGS AND AT LEAST MVFR VSBYS OVER THE WEST BY DAYBREAK TUESDAY. SOME SNOW/SLEET POSSIBLE AT THE ONSET AT BLF/ROA/BCB/LWB SHOULD CHANGE QUICKLY TO FZRA...WHILE LYH STARTS AS FZRA WITH PERHAPS A BIT OF PL. DAN WILL BE BORDERLINE ON FZRA BUT TEMPS SHOULD BE HUGGING 32-33F AT THE SFC SO INCLUDED A HOUR OR TWO OF -FZRA THERE EARLY TUESDAY. WARM NOSE ALOFT TO CHANGE FZRA TO RAIN AT ALL SITES TUESDAY AFTERNOON ALTHOUGH SPOTS LIKE KLWB/KLYH MAY KEEP -FZRA INTO MID OR LATE AFTERNOON. RAIN BECOMES HEAVY AT TIMES TUESDAY AFTERNOON ESPECIALLY AT BCB/ROA/LYH/DAN. WILL EXPECT TO SEE FLUCTUATIONS IN CIGS/VSBYS BASED ON RAINFALL RATES BUT OVERALL SHOULD BE IFR TO LIFR WITH MOUNTAIN OBSCURATIONS LIKELY. WITH THE STRONG SE FLOW ABOVE THE SURFACE WILL ALSO BE SEEING LLWS POTENTIAL AT ALL LOCATIONS THROUGH THE DAY TUESDAY AS LATEST SOUNDINGS INDICATE 35-45 KTS JUST ABOVE THE SURFACE ESPCLY IN THE AFTERNOON. THEREFORE INCLUDED LLWS AT MOST SPOTS FOR STRONG SOUTH TO SE FLOW DEVELOPING RIGHT AFTER SUNRISE ON TUESDAY. MODERATE TO HEAVY RAINFALL CONTINUES TUESDAY NIGHT WITH LOCATIONS ACROSS SE WVA TRANSITIONING BACK TO SNOW BY EARLY WEDNESDAY. THIS WILL KEEP LOW IFR/LIFR CIGS AND MVFR TO IFR VSBYS GOING TUESDAY NIGHT AS THE CORE OF THE LOW PRESSURE SYSTEM TRACKS ACROSS THE AREA. RAIN CHANGES TO A SIGNIFICANT UPSLOPE EVENT BY WED WITH PERHAPS A TRAILING DEFORMATION BAND OF SNOW WORKING EAST TOWARD THE BLUE RIDGE WED MORNING. THIS MAY RESULT IN A FEW INCHES OF SNOW ACCUMULATION AROUND KBLF/KLWB AND POSSIBLY A LIGHT AMOUNT EAST TO KBCB. WIND WILL ALSO BECOME AN ISSUE ACROSS THE MOUNTAINS WITH NW WIND GUSTS TO 45 KTS OR MORE WED WITH A SIGNIFICANT COASTAL LOW MOVING ACROSS COASTAL NEW ENGLAND. RAPID IMPROVEMENT WILL OCCUR ON THURSDAY AS THE STORM SYSTEM PULLS AWAY AND DRIER AIR WORKS IN...RESULTING IN WIDESPREAD VFR CONDITIONS. VFR THEN CONTINUES UNDER HIGH PRESSURE FOR FRIDAY THROUGH SATURDAY. && .HYDROLOGY... AS OF NOON EST MONDAY... MODEL CONSENSUS AND HPC GUIDANCE GENERALLY IN THE 2 TO 3 INCH RANGE OF LIQUID QPF FOR THE IMPENDING STORM EVENT ALTHOUGH SOME SREF ENSEMBLE MEMBERS SHOWING OVER 4 INCHES BY ABOUT 12Z WEDNESDAY THE 27TH. QUESTION IS WHAT IMPACT THE RUNOFF FROM THIS WILL HAVE ON AREA STREAMS AND RIVERS. POINT ONE IS THAT RIVERS ARE STARTING OFF AT VERY LOW LEVELS ESPECIALLY ACROSS THE LOWER PORTIONS OF OUR RIVER BASINS...ACROSS THE PIEDMONT. USGS DAILY STREAMFLOW PERCENTILES AS OF THIS MORNING ARE SHOWING NEARLY ALL PIEDMONT RIVER AND STREAM LOCATIONS RUNNING AT FLOWS BELOW THE 25TH PERCENTILE FOR THE DATE AND SOME BELOW THE 10TH PERCENTILE. THIS ALSO HOLDS TRUE FOR MUCH OF THE UPPER JAMES RIVER BASIN. 60-DAY RAINFALL DEFICITS HAVE BECOME QUITE SIGNIFICANT...REACHING 4 TO 6 INCHES IN MANY OF THESE BASINS OR AROUND 25 PERCENT OF NORMAL. DETERMINISTIC RIVER FORECASTS ISSUED THIS MORNING BY THE FOUR RFCS SERVING THE BLACKSBURG HYDRO SERVICE AREA INCLUDE 48 HOURS OF QPF THROUGH 12Z WEDNESDAY OF GENERALLY 2 TO 2.5 INCHES. AT OF THIS PACKAGE NO RIVERS ARE FORECAST TO REACH FLOOD STAGE OR EVEN ACTION STAGE (GENERALLY A FEW FEET BELOW FLOOD STAGE) ALTHOUGH SEVERAL COME CLOSE...INCLUDING THE NORTH FORK HOLSTON RIVER AT SALTVILLE AND GREENBRIER RIVER AT ALDERSON. THAT SAID HYDROLOGIC MODELS TEND TO HAVE SOME DIFFICULTY AFTER EXTENDED DRY PERIODS IN HANDLING RUNOFF WHICH IS GENERALLY MUCH MORE EFFICIENT IN THE COOL SEASON. HENCE...THE RESPONSE ON RIVERS REMAINS SOMEWHAT UNCERTAIN BUT NOT ENOUGH CONFIDENCE TO ISSUE A FLOOD WATCH. NOT EXPECTING MUCH IF ANY CONVECTION WITH THIS STORM SO RAINFALL RATES SHOULD REMAIN MODEST..IN THE 0.10 TO 0.25 INCH PER HOUR RANGE. BUT HIGHER RAINFALL RATES IN ANY ELEVATED STORMS THAT ARE ABLE TO DEVELOP COULD LEAD TO LOCALIZED RUNOFF PROBLEMS. THESE COULD BE HANDLED WITH SHORT-FUSE HYDROLOGIC PRODUCTS..FLOOD ADVISORIES OR EVEN FLASH FLOOD WARNINGS BUT THE LIKELIHOOD AT THIS POINT IS QUITE LOW FOR THIS TO OCCUR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM EST TUESDAY FOR VAZ018>020-023-024-035. WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR VAZ007-009>017-022-032>034-043>047-058-059. NC...WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ001>006-018>020. WV...WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM EST TUESDAY FOR WVZ045. WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR WVZ042>044. && $$ SYNOPSIS...RAB/WP NEAR TERM...JH/WP SHORT TERM...KK LONG TERM...SK AVIATION...JH/RAB/WP HYDROLOGY...PC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
201 PM CST SUN NOV 24 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 201 PM CST SUN NOV 24 2013 MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES LATER TONIGHT...ALONG WITH HOW MUCH AND POTENTIAL FOR FREEZING DRIZZLE. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...SUBTROPICAL STREAM TROUGH OVER ARIZONA...AND NORTHERN STREAM TROUGHING FROM CENTRAL CANADA INTO NEW ENGLAND. WITHIN THIS TROUGHING...A FAIRLY POTENT SHORTWAVE WAS SEEN DIVING SOUTHEAST THROUGH SASKATCHEWAN. AHEAD OF THIS TROUGH...VAD WIND PROFILES DEPICT 30-45 KT 925MB WINDS ACROSS THE EASTERN DAKOTAS AND MINNESOTA. THESE WINDS HAVE BEEN ADVECTING WARMER AIR TOWARDS THE FORECAST AREA...WITH 925MB TEMPS NOW PER RAP ANALYSIS AT -7 TO -12C...COMPARED TO -12 TO -14C AT 12Z. AIRMASS REMAINS RELATIVELY DRY...THOUGH...WITH PRECIPITABLE WATER VALUES JUST BELOW 0.25 INCH ACROSS THE UPPER MIDWEST. UPSTREAM IN THE WAKE OF THE SHORTWAVE...ANOTHER ARCTIC AIR SURGE WAS BREWING ACROSS THE NORTHWEST TERRITORIES WHERE TEMPERATURES ARE SITTING IN THE SINGLE DIGITS AND TEENS ABOVE ZERO. MODELS ARE IN GOOD AGREEMENT SLIDING THE POTENT SHORTWAVE OVER SASKATCHEWAN SOUTHEAST INTO NORTHERN PORTIONS OF MN...WI AND MI MONDAY MORNING...THEN HEADING OFF TO EASTERN ONTARIO DURING THE AFTERNOON. AS THE SHORTWAVE APPROACHES TONIGHT...SFC/925/850MB WINDS ALL INCREASE OVER THE FORECAST AREA...SETTING UP FOR A MUCH WARMER NIGHT. IN ADDITION...THESE WINDS WILL ADVECT IN A TONGUE OF RELATIVELY HIGHER MOISTURE FROM WESTERN KS AND EASTERN COLORADO...AS WELL AS FROM UP IN SOUTHERN MANITOBA...NOTED BY PRECIPITABLE WATER CLIMBING TO AROUND 0.5 INCH. THE HIGHEST PRECIPITABLE WATER IS CONFINED TO NORTHEAST IOWA AND SOUTHERN WI WHICH WOULD THEREFORE BE THE GREATEST CONCERN FOR PRECIPITATION. ALBEIT...THE GENERAL LOW AMOUNT OF PRECIPITABLE WATER WILL LIKELY LIMIT THE AMOUNT OF PRECIPITATION. REGARDING LIFT...280-290K ISENTROPIC SURFACES DEPICT AN INCREASE OF NET ADIABATIC OMEGA ACROSS THE FORECAST AREA BETWEEN 06 AND 12Z...THEN SLIDES OFF TO THE SOUTHEAST. GENERAL MODEL CONSENSUS HAS BEEN HOLDING STEADY SUGGESTING PRECIPITATION BREAKING OUT ACROSS NORTHEAST IOWA LATE TONIGHT...THEN SPREADING INTO SOUTHERN AND PERHAPS CENTRAL WISCONSIN MONDAY MORNING. SINCE SATURATION OCCURS FROM THE LOW TO MID LEVELS OF THE ATMOSPHERE...THE PRECIPITATION TYPE SHOULD BE MOSTLY SNOW...BUT CANNOT RULE OUT SOME FREEZING DRIZZLE POSSIBLE EITHER AT THE ONSET OR ON THE NORTH SIDE OF THE DEEPER MOISTURE. ANOTHER CONCERN IS PRECIPITATION BREAKING OUT ALONG THE POTENT SHORTWAVES WARM FRONT. 24.12Z GFS/HIRESARW AND 24.15Z SREF ALL SUGGEST THAT AS THE FRONT RUNS INTO LOW LEVEL STRATUS WHICH DEVELOPED LATE TONIGHT AHEAD OF IT...VERTICAL MOTION WITH THE FRONT CAN PRODUCE LIGHT PRECIPITATION. THIS WOULD APPEAR TO BE THE BEST CHANCE TO SEE FREEZING DRIZZLE. MUCH OF THE FORECAST AREA WOULD HAVE A CONCERN FOR THIS DEVELOPING...INCLUDING NORTHEAST IA AND SOUTHERN WI WHEN THE SNOW THERE DEPARTS. GIVEN THAT THE PROBABILITY OF FREEZING DRIZZLE IS LOW AT THIS TIME...ON THE ORDER OF 20 TO MAYBE 30 PERCENT...HAVE NOT ISSUED ANY WINTER WEATHER ADVISORIES. FURTHER SHIFTS MAY NEED TO ISSUE THEM...THOUGH...IF FREEZING DRIZZLE LOOKS MORE LIKELY TO OCCUR. TEMPERATURE WISE...WE SHOULD SEE TEMPERATURES HOLD EITHER NEARLY STEADY AND LIKELY RISE AFTER MIDNIGHT AS THE BREEZY SOUTH WINDS BRING IN WARMER AIR AT THE SURFACE. THERE IS POTENTIAL FOR SOME CLEARING MONDAY AFTERNOON...WHICH WITH 925MB TEMPS WARMING TO -2 TO - 4C IN THE AFTERNOON...HIGHS SHOULD CLIMB INTO THE 30S IN MOST LOCATIONS. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 201 PM CST SUN NOV 24 2013 FOCUS OF THE LONG TERM PERIOD IS ON AN ARCTIC COOL SHOT SLATED FOR TUESDAY INTO WEDNESDAY...AND ANY POSSIBLE PRECIPITATION THURSDAY INTO THE WEEKEND. MODELS DEPICT ANOTHER POTENT SHORTWAVE DROPPING OUT OF THE NORTHWEST TERRITORIES AND DOWN INTO THE FORECAST AREA ON TUESDAY. THIS POTENT SHORTWAVE REALLY HELPS TO BRING DOWN THE ARCTIC AIR OBSERVED UP THERE. AT THE SAME TIME...WITH THE ARCTIC COLD FRONTAL PASSAGE OCCURRING IN THE MORNING...LOW LEVEL MOISTURE GETS TRAPPED. THIS MOISTURE COMBINED WITH DAYTIME HEATING WILL MANIFEST ITSELF INTO A FAIRLY WIDESPREAD STRATUS DECK. STEEP LOW LEVEL LAPSE RATES ALONG WITH THE STRATUS DECK BEING IN THE DENDRITIC GROWTH ZONE IS LIKELY TO LEAD TO FLURRIES AT A MINIMUM...AND WOULD NOT BE SURPRISED IF SOME LOW CHANCES OF PRECIPITATION WILL NEED TO BE ADDED. WITH THE ARCTIC COLD FRONTAL PASSAGE TUESDAY MORNING...EXPECT TEMPERATURES TO NOT RISE MUCH AND IF ANYTHING WILL LIKELY FALL DURING THE AFTERNOON HOURS. 925MB TEMPS FALL TO -12C BY 00Z WEDNESDAY AND TO AROUND -14C BY 12Z WEDNESDAY. THERE IS A CONTINUING NORTHWEST BREEZE THROUGH THIS PERIOD WHICH WILL TEMPER A BIT ON HOW COLD WE GET TUESDAY NIGHT...AND LEANED MORE TOWARDS THE MET GUIDANCE FOR LOWS. ON THE FLIP SIDE...EXPECT COLDER WIND CHILLS BECAUSE OF THE BREEZE. SOME MODERATION TAKES PLACE IN 925MB TEMPS ON WEDNESDAY WITH SUN SO THAT TEMPERATURES CAN CLIMB BACK INTO THE LOW TO MID 20S. THE UPPER FLOW FROM THANKSGIVING AND BEYOND LOOKS TO CHANGE...GOING FROM THE NORTHWESTERLY PATTERN WE HAVE BEEN IN RECENTLY TOWARDS MORE ZONAL. THERE ARE EVEN HINTS IN THE 24.12Z ECMWF OF THE FLOW BACKING SOUTHWESTERLY EARLY NEXT WEEK. THIS PATTERN CHANGE WILL HELP DISLODGE SOME OF THE COLD AIR...THUS FOLLOWED A CONSENSUS FORECAST DEPICTING A GRADUAL MODERATING TREND FOR TEMPERATURES. REGARDING PRECIPITATION CHANCES...DURING THE PATTERN CHANGE...THERE ARE SHORTWAVE TROUGHS TRAVERSING ACROSS NORTHERN MN INTO UPPER MI ON THANKSGIVING AND ON SATURDAY. RIGHT NOW BASED ON THE TRACK WOULD SUGGEST THE BETTER CHANCES FOR PRECIPITATION WOULD STAY NORTH OF THE FORECAST AREA. HOWEVER...THAT SATURDAY SHORTWAVE TROUGH APPEARS TO TAKE A BIT FARTHER SOUTH TRACK COMPARED TO THE ONE ON THANKSGIVING...THUS 20 PERCENT CHANCES OF SNOW ARE IN THE FORECAST FOR BOTH SATURDAY AND SATURDAY NIGHT. FRIDAY AND SUNDAY APPEAR DRY AT THIS TIME BETWEEN SHORTWAVE TROUGHS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1157 AM CST SUN NOV 24 2013 CHALLENGING FORECAST PERIOD WITH RAPID AIR MASS CHANGE AND A COUPLE OF WEATHER SYSTEMS AFFECTING THE TAFS. A WEATHER SYSTEM WILL MOVE THROUGH THE REGION DURING THE SECOND PORTION OF THE TAF PERIOD FROM 25.06-18Z AND IS DISJOINTED. SOME MOISTURE RETURN IN THE LOW LEVELS WILL OCCUR ON VERY STRONG SOUTHWEST FLOW AHEAD OF A SYSTEM APPROACHING FROM CANADA. THIS MOISTURE HAS THE POTENTIAL FOR AN IFR OR LOW MVFR CIG AT THE TAF SITES. BECAUSE THE MOISTURE IS STILL QUITE FAR WEST /COLORADO/...AND SO MUCH MUST COME TOGETHER...THE CONFIDENCE IS LOWER ON THE EXACT HEIGHT THAT THE CIGS WILL COME IN AROUND SUNRISE. WITH LIFT ALSO IN THE AREA...SHOULD ENOUGH SATURATION OCCUR...FREEZING DRIZZLE WOULD BE POSSIBLE DURING THE MONDAY MORNING PERIOD. AT THIS TIME THE FEELING IS THAT THE MOISTURE IS NOT DEEP ENOUGH TO GROW DROPS LARGE ENOUGH TO FALL OUT AS FZDZ. HOWEVER...THE POTENTIAL IS THERE. THE SYSTEM WILL PRODUCE VERY STRONG LOW LEVEL WINDS IN THE LOWEST FEW THOUSAND FEET AGL...AND THUS LLWS WAS CONTINUED OVERNIGHT. THIS LLWS FORECAST IS OF HIGHER CONFIDENCE. THE PERIOD ENDS WITH A COLD FRONT PASSAGE...WINDS BECOMING && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1229 AM EST TUE NOV 26 2013 .SYNOPSIS... MOISTURE WILL OVERSPREAD THE FORECAST AREA TONIGHT AHEAD OF LOW PRESSURE DEVELOPING ALONG THE GULF COAST. THE LOW WILL MOVE NORTHEAST ACROSS THE OUR AREA TUESDAY AND TUESDAY NIGHT...BRINGING WIDESPREAD RAIN. THE LOW WILL LIFT NORTHEAST OF THE REGION WEDNESDAY WITH COLD AND DRY HIGH PRESSURE RETURNING THANKSGIVING DAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC COAST WILL MOVE EAST AS A WEATHER SYSTEM DEVELOPS ALONG THE GULF COAST OF LOUISIANA. LOWER CLOUDS NOW BLANKETING THE ENTIRE FA. WATER VAPOR IMAGERY AND MSAS ANALYSIS SHOWING A DIFLUENT PATTERN OVER THE WESTERN GULF OF MEXICO AND LOW PRESSURE HAS NOW DEVELOPED ALONG THE GULF COAST. ALL MODELS INDICATE INCREASING ISENTROPIC LIFT AHEAD OF THIS LOW WILL RESULT IN PRECIPITATION OVERSPREADING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST TONIGHT. THE HRRR PLUS SATELLITE AND RADAR TRENDS INDICATE THE PRECIPITATION WILL HOLD OFF UNTIL THE OVERNIGHT HOURS. THE MODELS INDICATE ENOUGH WARMING SHOULD OCCUR FOR ALL LIQUID PRECIPITATION. ALL SREF MEMBERS KEEP THE SURFACE TEMPERATURE ABOVE FREEZING LATE TONIGHT...EVEN IN THE NORTH PART. FREEZING RAIN IS NOT IMPOSSIBLE IN THE EXTREME NORTH SECTION...BUT BELIEVE PRECIPITATION WILL BE LIGHT AT THE ONSET LIMITING WET-BULB COOLING. ALSO...THE NAM AND GFS SHOW SURFACE WET-BULB TEMPERATURES RISING ABOVE FREEZING BEFORE SIGNIFICANT PRECIPITATION REACHES THE AREA LATE TONIGHT. DESPITE THE MODEL GUIDANCE...THERE MAY BE LAYERS OF DRY AIR ALOFT WITH WET-BULB COOLING WHICH COULD SUPPORT SLEET...MAINLY IN THE EXTREME NW PORTIONS OF THE FA. BELIEVE ANY SLEET WOULD BE LIGHT AND WITH SURFACE TEMPERATURES ABOVE FREEZING...SO NO ACCUMULATION SHOULD OCCUR. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... TUESDAY THROUGH WEDNESDAY...THE NAM AND GFS INDICATE THE BULK OF THE RAINFALL WILL OCCUR DURING THE TUESDAY AND TUESDAY NIGHT TIME FRAME WITH STRONG ISENTROPIC LIFT AND APPROACHING H5 SHORTWAVE TROUGH. THE NAM...GFS AND SREF MEAN SUPPORT TOTAL RAINFALL FROM 1.5 TO AROUND 2.0 INCHES. THE NAM SHOWS CROSS TOTALS NEAR 25 TUESDAY AND TUESDAY NIGHT...SO A FEW ELEVATED THUNDERSTORMS MAY OCCUR. THE SURFACE LOW WILL BE NORTHEAST OF THE AREA WITH THE UPPER TROUGH OVERHEAD WEDNESDAY. WE MAY HAVE LINGERING MORNING RAIN. STRONG COLD ADVECTION AND DRY AIR WILL POUR INTO THE AREA WEDNESDAY AFTERNOON. THE NAM LI-PATTERN INDICATES A WEDGE-TYPE PATTERN TUESDAY. WE LEANED TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE HIGH TEMPERATURE FORECAST. EXPECT A NEAR STEADY TEMPERATURE TUESDAY NIGHT. USED THE COLDER TEMPERATURE GUIDANCE WEDNESDAY BECAUSE OF LINGERING CLOUDINESS AND A SHARP UPPER TROUGH OVER OUR AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE GFS AND ECMWF ARE IN GOOD AGREEMENT SHOWING DRY HIGH PRESSURE DOMINATING DURING MUCH OF THE THE MEDIUM-RANGE PERIOD. AN ONSHORE FLOW AND WARM FRONT MAY SUPPORT RAIN MONDAY. BELOW NORMAL TEMPERATURES SHOULD CONTINUE THROUGH SUNDAY. THE GFS...ECMWF...EKD MOS PLUS GFS ENSEMBLE MEAN SUPPORT TEMPERATURES AROUND 10 DEGREES BELOW NORMAL THROUGH SUNDAY WITH NORMAL TEMPERATURES MONDAY. && .AVIATION /06Z TUESDAY THROUGH SUNDAY/... MVFR CONDITIONS THROUGH MOST OF THE OVERNIGHT PERIOD THEN DETERIORATING TO IFR BY 12Z. HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SHIFT EAST INTO THE ATLANTIC AS LOW PRESSURE ALONG THE GULF COAST PUSHES NORTHEASTWARD. DUE TO MOISTURE FLUX INTO THE AREA AHEAD OF THE APPROACHING WEATHER SYSTEM...CEILINGS HAVE LOWERED TO MVFR AT ALL TAF SITES. LIGHT RAIN SHOULD SPREAD INTO THE AREA BETWEEN 08Z AND 10Z AND CONTINUE SPREADING TOWARD THE NORTHEAST AS THE SURFACE LOW APPROACHES. BY 12Z...WIDESPREAD RAINFALL IS EXPECTED AND CONDITIONS SHOULD DETERIORATE RAPIDLY TO IFR. MAINLY MODERATE RAIN ON TUESDAY BUT CANNOT RULE OUT SOME HEAVY RAIN AT TIMES. MODEL SOUNDINGS AND LOCAL SCHEME SHOWING WIND SHEAR DEVELOPING TUESDAY MORNING. INTRODUCED WIND SHEAR OF 35 KNOTS FROM 12Z TO 24Z. ALSO WITH INCREASING INSTABILITY ALOFT...A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE...ESPECIALLY ACROSS THE EASTERN MIDLANDS TAF SITE OGB...BUT CONFIDENCE WAS TOO LOW TO INCLUDE IN THIS TAF PACKAGE. EXTENDED AVIATION OUTLOOK...AN EXTENDED PERIOD OF CIG/VSBY RESTRICTIONS ARE POSSIBLE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS A LOW PRESSURE SYSTEM FROM THE GULF OF MEX CROSSES THE SOUTHEASTERN STATES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
156 AM EST TUE NOV 26 2013 .SYNOPSIS... ISSUED AT 154 AM EST TUE NOV 26 2013 A REINFORCING SHOT OF COLD AIR WILL SET THE STAGE FOR A POTENTIAL HEAVY LAKE EFFECT SNOW EVENT TUESDAY NIGHT THROUGH WEDNESDAY ACROSS FAR SOUTHWEST LOWER MICHIGAN AND PORTIONS OF NORTHWEST AND NORTH CENTRAL INDIANA. && .UPDATE... ISSUED AT 700 PM EST MON NOV 25 2013 LEAD SHORTWAVE APPEARS TO BE QUITE SHEARED IN NATURE STRETCHING FROM SOUTHERN LOWER MICHIGAN BACK INTO CENTRAL ILLINOIS THIS EVENING. THIS WAVE WILL CONTINUE TO SLIDE EAST THROUGH THE AREA THROUGH THE LATE EVENING. THE COMBINATION OF WEAK DPVA WITH THIS FEATURE AND ASSOCIATED DOWNSTREAM WEAK 750-650 HPA FRONTOGENESIS WILL SUPPORT AREA OF -SN OVERSPREADING MUCH OF EASTERN AND SOUTHEAST PORTIONS OF THE AREA THROUGH MIDNIGHT. DRY NATURE TO AIR MASS AND ELEVATED NATURE OF FORCING WILL ONLY LEAD TO A FEW TENTHS OF SNOW ACCUMULATION FOR MOST LOCATIONS HOWEVER. MUCH DRIER MID LEVEL AIR ADVECTING IN BEHIND THIS LEAD SHORT WAVE HAS CUT OFF PRECIP ACROSS THE FAR NORTH EARLY THIS EVENING. WATER VAPOR IMAGERY/21Z RAP INITIALIZATION DO SUGGEST PRESENCE OF NEXT UPSTREAM VORT ACROSS SOUTHERN MINNESOTA WHICH WILL SLIDE INTO THE WESTERN GREAT LAKES LATE TONIGHT. NOT COMPLETELY OUT OF THE QUESTION THAT SOME PATCHY FREEZING DRIZZLE COULD ACCOMPANY THIS WEAK FORCING...BUT GIVEN EXPECTED VERY LIGHT NATURE TO THE DRIZZLE IF IT OCCURS WOULD EXPECT MINIMAL TO NO IMPACT SO WILL CONTINUE TO OMIT FROM THE FORECAST. ONLY TWEAK TO PREVIOUS FORECAST WAS TO INCREASE POPS SLIGHTLY ACROSS CENTRAL PORTIONS OF THE AREA WHERE IT APPEARS SOME VERY WEAK ELEVATED FGEN RESPONSE HAS OCCURRED OVER THE PAST HOUR OR TWO. EVEN ACROSS THESE LOCATIONS...ACCUMULATIONS SHOULD ONLY TOTAL A TENTH OR TWO. ANOTHER WEAK WAVE FROM SOUTHERN STREAM ACROSS CENTRAL ILLINOIS EVIDENT ON WATER VAPOR IMAGERY MAY CLIP SOUTHERN PORTIONS OF FORECAST THROUGH EARLY PORTIONS OF THE OVERNIGHT THAT COULD LEAD TO BRIEF ENHANCEMENT OF WEAK ELEVATED FGEN...BUT LITTLE OR NO ACCUMULATION IS EXPECTED. TREND OF DIMINISHING POPS FROM NORTHWEST TO SOUTHEAST STILL APPEARS REASONABLE AND NO OTHER CHANGES MADE TO PREVIOUS FORECAST AT THIS TIME. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 340 PM EST MON NOV 25 2013 LEAD NORTHERN STREAM S/W CURRENTLY DIVING SOUTHEAST ACROSS UPPER GREAT LAKES. WEAK SMALLER SCALE WAVES STREAMING NORTHEAST TOWARD THE LOWER GREAT LAKES NOTED ON W/V IMAGERY THIS AFTN...EMANATING FROM STRONG SOUTHERN LOW ACROSS PANHANDLE REGION. THE PHASING OF THESE WEAKER P/V ANOMALIES ACROSS THE AREA...COMBINED WITH COMPACT CORRIDOR OF DECENT ISENTROPIC LIFT...PROVIDING WIDESPREAD PRECIPITATION ACROSS THE REGION PER RADAR. THESE SNOW SHOWERS HAVE BEEN STRUGGLING TO REACH THE GROUND ALL DAY PER UPSTREAM SFC OBS...GIVEN STOUT DRY BOUNDARY LAYER AND SFC DEWPOINT DEPRESSIONS ON THE ORDER OF 10-15F. CONTINUED WITH PREVIOUS FCST TREND...MENTIONING LIGHT SNOW WORDING/FLURRIES...ALONG WITH LIGHT ACCUMULATIONS ACROSS THE AREA. CONFIDENCE HAS WANED FOR ANY ACCUMULATIONS GIVEN RADAR TRENDS...HOWEVER STREAM OF MID LVL MOISTURE ADVECTING NE INTO THE AREA NOTED ON W/V MAY LEND TO ENHANCE THESE RETURNS AND HELP TOP DOWN SATURATION OF THE LAYER...COINCIDENT WITH THE CORRIDOR OF ISENTROPIC LIFT. CORRIDOR OF LIFT STRETCHES OFF TO THE EAST AFTER MIDNIGHT...WITH DIMINISHING POPS REFLECTED IN THE GRIDS. STRONGER NORTHERN STREAM P/V ANOMALY WILL SURGE SOUTHEAST THROUGH THE REGION ON TUESDAY...AND WILL ATTEMPT TO PHASE WITH SOUTHERN STREAM P/V ANOMALY LATE TOMORROW AND WEDNESDAY WELL SOUTHEAST OF THE REGION. ATLANTIC COAST SFC CYCLONE WILL DEVELOP IN RESPONSE TO THESE FEATURES...AND BRING WIDESPREAD PRECIP TO MUCH OF THE EASTERN US. HOWEVER...BEST ISENTROPIC UPGLIDE SHOULD KEEP SNOWFALL SOUTH AND EAST OF THE AREA THROUGH TUESDAY...ESPECIALLY GIVEN THE AGGRESSIVE NATURE OF THE NORTHERN STREAM ENERGY SURGING SOUTHEAST THROUGH THE AREA. THEREFORE...HAVE KEPT POPS OUT OF THE TUESDAY PERIOD ACROSS THE SOUTHEAST PORTION OF THE AREA...BUT HEDGED WITH A CHANCE FLURRIES MENTION CLOSE TO THE EDGE OF THE BEST MOISTURE/LIFT GRADIENTS. NO MAJOR CHANCES TO TEMPS TONIGHT/TUESDAY. ACCOMPANYING THIS STRONG NORTHERN P/V ANOMALY IS ANOTHER EARLY SEASON SURGE OF ARCTIC AIR. THIS WILL PUSH THROUGH THE AREA TUESDAY AFTERNOON. KEPT WITH A FLURRY MENTION ACROSS THE AREA IN THE AFTERNOON IN THE WAKE OF THE ARCTIC FRONT. LAKE RESPONSE SHOULD ACTIVATE TUESDAY AFTERNOON AS 850MB TEMPS CRASH TO -12C TO -13C BY 21Z TUESDAY. SHOULD BE RATHER DISORGANIZED BEFORE 00Z...AS LOW LVL NORTHWEST FLOW SHOULD KEEP BANDING TO A MINIMUM DURING THIS PERIOD. WENT WITH A FEW TENTHS OF SNOW ACCUMULATION ACROSS FAR SW LWR MI FROM 18Z TO 00Z...BEFORE FLOW VEERS NORTHERLY INTO THE OVERNIGHT...LEADING TO A SIGNIFICANT SINGLE BAND EVENT IN THE LONG TERM PERIOD. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 340 PM EST MON NOV 25 2013 ...SIGNIFICANT LAKE EFFECT SNOW EXPECTED TUE NIGHT-WED... FCST THIS AFTN PREDICATED ON SHARPER H5 SOLUTIONS ALOFT INCLUDING NAM/GEM/EC AND VARIOUS HIGHRES GUIDANCE AS POTENT SRN STREAM SW PHASES W/SECONDARY NRN STREAM DROPPING SWD THROUGH NRN SK THIS AFTN. VIGOROUS/SHARP LL CAA BURST XPCD TUE NIGHT W/DEEP NRLY LONG AXIS FETCH DVLPG. CLEAR INDICATIONS OF LK SP CONNECTION WHICH WILL MOST CERTAINLY AID IN BREATH OF LATENT MSTR FLUX AND MODULATE SNOWBAND INTENSITY HIGHER. 30-35KT MEAN CLD BEARING LYR FLW SHLD ALSO YIELD A FURTHER INLAND PENETRATION OF SNOWBANDS BUT WHERE REMAINS A BIG QN. TYPICAL W-E SPREAD NOTED THIS AFTN ALTHOUGH A DECIDED CONSENSUS LIES W/ERN CLUSTER OF SOLUTIONS INCLUDING MOST HIGHRES RENDITIONS ALG W/GEM AND 4KM NAM. AT THIS POINT GIVEN HOLIDAY TRAVEL CONCERNS WILL BROAD BRUSH A WATCH FOR LT TUE NIGHT-WED EVE ACRS MUCH OF THE WRN CORNER. HWVR IMPACTS WILL LIKELY EXTEND FARTHER DOWNSTREAM AND WILL ADDRESS IN HWO UPDATE. FVRBL DGZ LOCATION WITHIN LVL OF NON DVRG NOTED IN XSCTNS ALG W/MAXIMIZED RH AND STG ASCENT WOULD PORTEND A PD OF 1-2 INCH SNOWFALL RATES LIKELY VRY LT TUE NIGHT INTO WED AFTN BFR WKNG. CONSERVATIVE AGGREGATED QPF YIELDS A BROAD 6-10 INCH SNOW PLUME W/OBVIOUS HEAVIER ACCUMS TIED TO PLACEMENT OF LK SP CONNECTED PLUME AND LESSOR ACCUMS TIED TO WHERE WEAKER WRN DIPOLE DVLPS. BAND XPCD TO BREAKUP RAPIDLY WED EVE IN RESPONSE TO QUICK FLATTEN OF FLW ALOFT AS EAST COAST STORM LIFTS OUT AND AHD OF NXT UPSTREAM DISTURBANCE. TEMPS THROUGH THE PD CONT COLD BUT MODERATION ON TAP THIS WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 153 AM EST TUE NOV 26 2013 HIGH END MVFR TO VFR MET CONDS PREVAIL OVERNIGHT ACRS NRN IN WITH FLURRIES COMING TO END AT KFWA SHORTLY. OTHERWISE FOCUS ON DEVELOPMENT OF SIG LAKE EFFECT SNOWFALL FOR KSBN AREA LATE IN FORECAST PD. TEMPO FUELING REQUIREMENTS THERE WITH HIGH LIKELIHOOD OF FURTHER DEGRADATION INTO IFR RANGE IN HEAVIER SNOW SQUALLS...ESPECIALLY JUST BYND CURRENT FCST PD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH WEDNESDAY EVENING FOR INZ003-004-012>015. MI...LAKE EFFECT SNOW WATCH FROM LATE TONIGHT THROUGH WEDNESDAY EVENING FOR MIZ077. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR LMZ043-046. && $$ UPDATE...MARSILI SYNOPSIS...MURPHY SHORT TERM...NG LONG TERM...T AVIATION...MURPHY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1157 PM CST Mon Nov 25 2013 .UPDATE... ISSUED AT 1157 PM CST MON NOV 25 2013 The AVIATION section has been updated for the 06Z TAF issuance. UPDATE ISSUED AT 742 PM CST MON NOV 25 2013 A slightly more modest change in precipitation chances and other sensible weather elements (weather, temperature, dewpoint, wind, etc) for tonight and Tuesday morning, mainly over West Kentucky. The current wave of precipitation and sub-synoptic lift is moving out of the area, creating a small droplet size area of rain/mist, as well as snow over the eastern 1/3 of the WFO PAH County warning area. Regional radar mosaic still showing 0 to 15/20 dBZ returns over Central Arkansas, Southeast Misouri, Southeast Illinois, and into Northwest Kentucky and Southwest Indiana shortly after 01z (7 pm CST) this evening. This is coincident with the southern edge of a differential deformation zone/moisture gradient on the 7.0 micron (sensitive near 700 mb) and 7.4 micron (sensitive near 850 mb) GOES Sounder Water Vapor channels. On the 11-3.9 micron GOES IR difference channel, the aforementioned radar echoes are centered within the mean plume of ice clouds, serving as seeder-feeder source region. The GEM (Canadian), SREF (Short Range Ensemble Forecast), deterministic 18z GFS numerical guidance are similar to the high resolution 3km HRRR model guidance for this evening and overnight. We should see a resurgence of PoPs/Weather from the southwest into the Missouri Bootheel and Southwest Kentucky after midnight (06z). A sharp northern PoP/Weather gradient should develop over West Kentucky after midnight, slowly working east-northeast through 8 am CST Tuesday, then continue to shift east during the day on Tuesday. By 9 am CST Tuesday, most areas should remain above freezing over the entire WFO PAH CWA, eliminating any travel concern. For now, the most concentrated area for travel concerns between 11 pm Monday and 8 am Tuesday will be from Paducah KY (KPAH) and Owensboro KY (KOWB) southward 25 to 30 miles through 5 am CST, working slightly more southward another 10 to 15 miles between 5 am - 8 am CST. The combination and duration of temperatures slightly below freezing, PoPs above 40%, and differential lift may lead some slight glazing on elevated surface and some roadways. For now, will issue a longer term Special Weather Statement to address this area of travel concern, as well as post a Weather Story graphic on the NWS Paducah web page and social media outlets. May also highlight in the Hazardous Weather Outlook as well. Given the marginal nature of the precipitation amounts (between 0.04" - 0.07") it will be a judgement call whether an advisory will be needed overnight, since critical temperatures will focused in areas where total precipitation will be less than 0.05" between 11 pm and 8 am CST. Given the effectiveness of de-icing agents (salt, etc...) most roads should remain in good shape. The only areas of concern will be any untreated roadways. && .SHORT TERM...(This Evening through Tuesday night) ISSUED AT 239 PM CST MON NOV 25 2013 Models were obviously too slow with precip onset with this initial wave. Not an uncommon error. Light sleet, light rain light snow mix across the area. Most notable precip has been over west KY and southeast MO, near the TN state line over to the MO bootheel region. We will maintain our SPS (Special Weather Statement) approach vs. an advisory. A few slick spots certainly possible though not getting really any reports of that. Temperatures per KY mesonet into SEMO at or above freezing even where precip has occurred. Site near Hickman is down to 32F. Overall, still not a big deal event. This lead wave will push the afternoon activity on to the east. The question then becomes, how much more will we see overnight into early Tuesday. Will maintain slight better chances overnight south and east and taper off low chance PoPs NW overnight, and continue with our SE 1/3 of the area PoPs Tuesday as the southern and northern stream systems interact and draw moisture into this area. Should be dry over the remainder of the region Tuesday. A minimal mix precip type possible tonight into early Tuesday a.m. Then precip should transition to mainly light rain. Tuesday night will be dry and colder as arctic high pressure builds south into the area. .LONG TERM...(Wednesday through Monday) ISSUED AT 239 PM CST MON NOV 25 2013 With precipitation having moved east of the PAH forecast area, Wednesday will see clearing skies as chilly and breezy conditions persist through the day. With highs only in the lower 30s, wind chill readings in the morning will start out in the single digits to around 10 degrees, only improving to the lower 20s by afternoon. The coldest period of the extended will continue into Wednesday night, with lows in the middle to upper teens. Northwest winds at 5 to 10 mph in the evening will decrease and gradually turn back to the southwest by daybreak. High pressure over the central plains Wednesday will slide east of the PAH fa by Thursday morning, thus the winds becoming southwest. Southwest flow will lead to a gradual warm up through the weekend, though readings will remain below normal. High temperatures on Thanksgiving will only reach the middle to upper 30s, moderating to the upper 40s to around 50 degrees Saturday and Sunday. Lows Saturday night are expected to stay above freezing, which will be the first night with above freezing temperatures since last weekend. ECMWF brings a surface low into the Great Lakes region by 12z Sunday, dragging a cold front into the Mississippi River valley. GFS is about 12 hours slower than the ECMWF. ECMWF spreads rain across much of the PAH fa Saturday night, while GFS holds off until late Sunday into Sunday night. Went with a compromise, keeping Saturday night dry then including slight to low chance pops for mainly southern Illinois and southeast Missouri on Sunday. Went with chance pops across the entire area Sunday night into Monday. Fortunately, temperatures look to be warm enough through the event to keep precip all liquid. && .AVIATION... ISSUED AT 1157 PM CST MON NOV 25 2013 The upper-level storm system over Texas will shift east and phase with a northern stream system diving over the Mississippi River by 06Z Wednesday. Lots of moisture will be drawn northward over west Kentucky tonight, as temperatures reach saturation near the freezing mark. Most of the precipitation will be in the very low- levels, so drizzle or freezing drizzle would be the main precipitation type. Most guidance is indicating a brief window toward 12Z where deeper saturation may occur. Guidance also indicates some warming aloft by then, so any snow aloft would likely melt. Rain or sleet would be the main precipitation type. Will assume temperatures stay just above freezing, so will keep rain/sleet combination and not mention freezing rain/drizzle. Ceilings will likely drop to IFR levels in the east and possibly at all sites straddling 12Z. Ceilings should lift considerably by mid-morning. Surface high pressure will build east across the area through the afternoon, so gusty north winds will spread eastward across the area. The gustiness will pick up during the evening throughout the area. Some strato cu ceilings are likely later in the evening. MVFR levels cannot be ruled out. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
328 AM EST TUE NOV 26 2013 .SYNOPSIS... AS LOW PRESSURE MOVES UP THE EAST COAST...A WINTRY MIX WILL ENTER THE REGION BEFORE CHANGING TO ALL SNOW AFTER MIDNIGHT. SNOW WILL DIMINISH WEDNESDAY INTO THURSDAY...WITH DRY WEATHER UNTIL AT LEAST SUNDAY. && .NEAR TERM /THROUGH WEDNESDAY/... A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE. NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL. THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE DOMINANT PRECIPITATION TYPE. BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING. TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES. ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE EFFECT MACHINE TO START UP. ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE NEEDED TO ANY OF THE ADVISORIES OR WARNINGS. && .SHORT TERM /WEDNESDAY NIGHT/... UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL BRING LOWS DOWN INTO THE UPPER TEENS. && .LONG TERM /THURSDAY THROUGH MONDAY/... DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... GRADUAL DETERIORATION TO GENL IFR CAN BE EXPECTED TODAY AS LGT SN...THEN A MIXTURE OF WINTRY PCPN SPREADS OVR THE REGION AS LOW PRES EMERGES FM THE GULF COAST AREA. IFR CONDITIONS WL THEN PREVAIL THROUGH TNGT WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW. .OUTLOOK.../WEDNESDAY THROUGH SATURDAY/... WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM EST THURSDAY FOR MDZ001. OH...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR OHZ039>041-048>050-057-058. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR OHZ059-068-069. PA...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR PAZ013>016-020>022. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR PAZ023-029. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR PAZ031-073-075. WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM EST THURSDAY FOR PAZ074-076. WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR PAZ007>009. WV...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR WVZ001-002. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR WVZ003-004. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR WVZ012-021-022. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 4 AM EST THURSDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
354 AM EST TUE NOV 26 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY NIGHT...THEN LINGER THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM TUESDAY... PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A STRENGHTNEING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS... WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA. THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO... AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE MODELS ARE TOO AGGRESIVE ERRADICATING THE WEDGE AND BAREELING THE WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD TO IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW CORES THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE THE FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION SEEMS ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE RESIUDAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY CHANGE FROM AFTERNOON TEMPS. THE MORE INLAND WARM SECTOR PENERTATION ALSO RAISES CONCERN FOR THE POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME LOW AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW PRESSURE SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED TROUGH AXES ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL PLAIN AND FAR EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE LLJ ACCELERATES ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED SURFACE-BASED...OR NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM. FORECST BUFR SOUNDINGS SUGGEST CONVECTION OF THE ELEVATED VARIETY COULD OCCUR IN THE CAD REGIME AS WELL...WITH UP TO A FEW HUNDRED J/KG OF MUCAPE INDICATED ACROSS ALL OF CENTRAL NC FOR SEVERAL HOURS THIS EVENING-EARLY TONIGHT. A MID LEVEL DRY SLOT MAY LARGELY END PRECIPITATION FOR A TIME OVERNIGHT...AFTER THE RAIN BECOMES HEAVY AT TIMES DURING THE AFTERNOON AND EVENING HOURS. THE BULK OF THE PREVIOUSLY FORECAST ONE TO TWO INCHES OF SOAKING RAIN (WELL BELOW FLASH FLOOD GUIDANCE)... HIGHEST WEST...WILL HAVE FALLEN BY THAT TIME. THE LEADING EDGE OF CONCENTRATED DCVA ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE TROUGH OVER WEST TX SHOULD THEN RESULT IN THE REDEVELOPMENT OF RAIN...PERHAPS IN THE FORM OF A BAND OF SHALLOW ELEVATED CONVECTION...LATE TONIGHT INTO EARLY WEDNESDAY. AREAS OF FOG... INCLUDING SOME DENSE OVER THE WESTERN PIEDMONT...WILL ALSO BE PROBABLE ON THE COOL SIDE OF THE BOUNDARY TONIGHT. && .SHORT TERM /WEDNESDAY/... AS OF 345 AM TUESDAY... GUIDANCE REMAINS CONSISTENT THAT THE DEPTH OF THE SATURATED LAYER WILL STRUGGLE TO REACH THE MINUS 10 LEVEL...AS THE STRONGEST HEIGHT FALLS/DYNAMICS ALOFT PIVOT NORTHEASTWARD. THE EXCEPTION WILL BE OVER THE WESTERN AND NORTHERN PIEDMONT...WHERE BRIEF DEEPENING TO NEAR MINUS 12...IN BAND OF LAST GASP DEFORMATION PRECIPITATION...IS FORECAST TO OCCUR IN THE SEVERAL HOURS CENTERED AROUND 18Z. A FEW WET FLAKES MAY CONSEQUENTLY MIX WITH THE RAIN AS THE PRECIPITATION COMES TO AND END DURING THE AFTERNOON. AREAS OUTSIDE OF THE DEFORMATION BAND...NAMELY OVER THE COASTAL COLAN AND PERHAPS SANDHILLS...WILL LIKELY RECEIVE LITTLE TO NO ADDIITIONAL RAIN...WITH JUST A PARTLY CLOUDY SKY IN THE DRY SLOT. ALL AREAS WILL EXPERIENCE STRONG CAA...HOWVEER...WITH TEMPERATURES TUMBLING INTO THE 40S... AND 30S OVER THE WESTERN PIEDMONT...DURING THE LATE MORNING TO EARLY AFTERNOON HOURS. BLUSTERY NW WINDS WILL ALSO GUST TO BETWEEN 30 AND 35 MPH AS THE FRESH ARCTIC AIR MASS SURGES ACROSS THE STATE BEHIND THE RAPIDLY DEPEENING LOW BOUND FOR NEW ENGLAND AND EASTERN CANADA...WHICH WILL YIELD WIND CHILL VALUES ABOUT 15 DEGREES COOLER THAN THE AFORMENTIONED AIR TEMPS IN THE 30S-40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AS OF 250 AM TUESDAY... WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY... AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT. SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT. SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 115 AM TUESDAY... 24 HOUR TAF PERIOD: THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE. CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO 40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL. LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT. CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT WEEK WHEN THE NEXT SYSTEM APPROACHES. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...KC AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
335 AM EST TUE NOV 26 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY NIGHT...THEN LINGER THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM TUESDAY... PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A STRENGHTNEING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS... WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA. THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO... AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE MODELS ARE TOO AGGRESIVE ERRADICATING THE WEDGE AND BAREELING THE WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD TO IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW CORES THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE THE FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION SEEMS ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE RESIUDAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY CHANGE FROM AFTERNOON TEMPS. THE MORE INLAND WARM SECTOR PENERTATION ALSO RAISES CONCERN FOR THE POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME LOW AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW PRESSURE SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED TROUGH AXES ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL PLAIN AND FAR EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE LLJ ACCELERATES ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED SURFACE-BASED...OR NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM. FORECST BUFR SOUNDINGS SUGGEST CONVECTION OF THE ELEVATED VARIETY COULD OCCUR IN THE CAD REGIME AS WELL...WITH UP TO A FEW HUNDRED J/KG OF MUCAPE INDICATED ACROSS ALL OF CENTRAL NC FOR SEVERAL HOURS THIS EVENING-EARLY TONIGHT. A MID LEVEL DRY SLOT MAY LARGELY END PRECIPITATION FOR A TIME OVERNIGHT...AFTER THE RAIN BECOMES HEAVY AT TIMES DURING THE AFTERNOON AND EVENING HOURS. THE BULK OF THE PREVIOUSLY FORECAST ONE TO TWO INCHES OF SOAKING RAIN (WELL BELOW FLASH FLOOD GUIDANCE)... HIGHEST WEST...WILL HAVE FALLEN BY THAT TIME. THE LEADING EDGE OF CONCENTRATED DCVA ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE TROUGH OVER WEST TX SHOULD THEN RESULT IN THE REDEVELOPMENT OF RAIN...PERHAPS IN THE FORM OF A BAND OF SHALLOW ELEVATED CONVECTION...LATE TONIGHT INTO EARLY WEDNESDAY. AREAS OF FOG... INCLUDING SOME DENSE OVER THE WESTERN PIEDMONT...WILL ALSO BE PROBABLE ON THE COOL SIDE OF THE BOUNDARY TONIGHT. && .SHORT TERM /WEDNESDAY/... AS OF 320 PM MONDAY... FOR WED/WED NIGHT: MODELS ARE IN GOOD AGREEMENT ON PLACING THE PRIMARY SURFACE LOW NEAR NYC WED MORNING AND THE SECONDARY WEAKER LOW OVER THE VA TIDEWATER... WHICH BOTH CONSOLIDATE INTO A SINGLE LOW OVER MAINE BY DAY`S END. THE SOUTHERN STREAM PORTION OF THE STORM SYSTEM WILL BE WEAKENING AS IT LIFT NORTHEASTWARD THROUGH NC FROM MID MORNING THROUGH EARLY AFTERNOON... BUT IT WILL STILL BE QUITE POTENT INDUCING STRONG FORCING FOR ASCENT AS IT MAINTAINS A NEGATIVE TILT. THE MID-UPPER LEVELS ACCORDING TO FORECAST SOUNDINGS WILL DRY OUT QUITE A BIT IN THE MORNING AS A DRY SLOT PUNCHES IN FROM THE SOUTH... SUGGESTING A TRANSITION TO PATCHY DRIZZLE (OR PERHAPS A LITTLE FREEZING DRIZZLE IN THE FAR NW CWA WHERE SURFACE WET BULB TEMPS WILL BE DROPPING TO AROUND 32F) AS THE COLDER AIR ARRIVES POST-FRONT... WITH THE LOWEST 4 KM OR SO STAYING SATURATED. A SLUG OF DPVA ASSOCIATED WITH THE NORTHERN STREAM PORTION OF THE MID LEVEL LONGWAVE TROUGH SWINGS THROUGH NW NC WED AFTERNOON ATTENDING A DEFORMATION ZONE ALOFT... HOWEVER THESE TOO SHOULD BE WEAKENING AND DON`T APPEAR TO PROVIDE ENOUGH DEEP LAYER LIFT TO RE- SATURATE THE AIR ABOVE -10C. AS SUCH... BELIEVE THAT A FEW WET FLAKES WILL BE POSSIBLE ACROSS THE NW AND FAR NRN PIEDMONT WED AFTERNOON AS THE COLUMN COOLS... BUT IT SHOULD BE INCONSEQUENTIAL GIVEN THE BRIEF WINDOW OF OPPORTUNITY AND LIMITED MOISTURE ALOFT. PASSAGE OF A WEAK POST-FRONTAL SURFACE TROUGH WED AFTERNOON WILL SWING WINDS AROUND TO A UNIFORMLY NW DIRECTION... YIELDING CLEARING SKIES BY EARLY EVENING AS DOWNSLOPE FLOW AND DRY AIR ADVECTION TAKES OVER. WITH A TIGHTENING MSLP GRADIENT DUE TO THE STRENGTHENING DEPARTING SURFACE LOW... THESE BRISK NW WINDS DURING THE DAY ARE EXPECTED TO TOP OUT AT 15-20 MPH SUSTAINED WITH GUSTS OVER 30 MPH POSSIBLE AS STRONG 925 MB WINDS NEAR 35 KT MIX DOWN TO THE SURFACE. WED HIGHS ARE APT TO BE VERY CLOSE TO THE MORNING LOWS... WITH PLUNGING THICKNESSES THROUGH THE DAY WITH STEADY COLD AIR ADVECTION CAUSING TEMPS TO FALL SLOWLY THROUGH THE DAY. EARLY DAY HIGHS FROM THE UPPER 30S NW TO LOWER 60S IN THE EASTERN COASTAL PLAIN... FALLING TO THE MID 30S NW TO MID 40S EAST BY LATE AFTERNOON. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AS OF 250 AM TUESDAY... WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY... AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT. SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT. SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 115 AM TUESDAY... 24 HOUR TAF PERIOD: THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE. CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO 40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL. LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT. CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT WEEK WHEN THE NEXT SYSTEM APPROACHES. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...GIH LONG TERM...KC AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
252 AM EST TUE NOV 26 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY NIGHT...THEN LINGER THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM MONDAY... TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT... MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER... WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT. TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z... WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND DAYBREAK. AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND 15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE... WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN- SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF- LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST FORSYTH COUNTY. LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S). && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 PM MONDAY... TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING. POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1 CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED AMOUNTS AROUND 2.5 INCHES. TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS 15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES FROM PREVIOUS FORECAST. TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT. EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT (10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT. TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY. TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN THE LOW-MID 60S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 250 AM TUESDAY... WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY... AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT. SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT. SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 115 AM TUESDAY... 24 HOUR TAF PERIOD: THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE. CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO 40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL. LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT. CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT WEEK WHEN THE NEXT SYSTEM APPROACHES. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...MWS NEAR TERM...BSD SHORT TERM...WSS LONG TERM...KC AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
251 AM EST TUE NOV 26 2013 .SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY NIGHT...THEN LINGER THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM MONDAY... TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT... MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER... WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT. TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z... WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND DAYBREAK. AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND 15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE... WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN- SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF- LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST FORSYTH COUNTY. LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S). && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 PM MONDAY... TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING. POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1 CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED AMOUNTS AROUND 2.5 INCHES. TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS 15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES FROM PREVIOUS FORECAST. TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT. EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT (10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT. TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY. TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN THE LOW-MID 60S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 250 AM TUESDAY... WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY... AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT. SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT. SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 115 AM TUESDAY... 24 HOUR TAF PERIOD: THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE. CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO 40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL. LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT. CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT WEEK WHEN THE NEXT SYSTEM APPROACHES. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...MWS NEAR TERM...BSD SHORT TERM...WSS LONG TERM...KC AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
114 AM EST TUE NOV 26 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL DEVELOP IN THE GULF OF MEXICO TONIGHT...THEN INTENSIFY AND TRACK NORTHEAST ALONG THE CAROLINA AND MID ATLANTIC COAST LATE TUESDAY THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM MONDAY... TONIGHT: SURFACE HIGH PRESSURE IS CURRENTLY SHIFTING OFF THE NORTH CAROLINA COAST. HOWEVER... THE LOW LEVELS REMAIN QUITE DRY ACROSS THE AREA IN THE WAKE OF THE DEPARTING ARCTIC HIGH PRESSURE. ALOFT... MID AND UPPER LEVEL MOISTURE IS BEGINNING TO STREAM INTO THE AREA IN ASSOCIATION WITH A STRENGTHENING LOW PRESSURE SYSTEM OVER THE GULF COAST STATES. THIS SYSTEM WILL QUICKLY APPROACH THE AREA OVERNIGHT... SPREADING OVERCAST SKIES AND EVENTUALLY PRECIP INTO THE WEST/NORTHWEST PIEDMONT AFTER MIDNIGHT... THEN SPREADING EASTWARD ACROSS THE REST OF THE AREA AFTER DAYBREAK. IN FACT WE ARE ALREADY SEEING SOME RETURNS ON RADAR THIS EVENING. CANT RULE OUT A FEW SPRINKLES OR SLEET PELLETS LATE THIS EVENING WITH THE BEST RETURNS... BUT THE AMOUNT OF DRY AIR IN THE LOW LEVEL (AS EVIDENT BY THE 00Z KGSO SOUNDING ALONG WITH RAP MODELS SOUNDING FOR THE WESTERN PIEDMONT) SUGGEST ANY PRECIP WILL HAVE A HARD TIME REACHING THE GROUND OVER THE COURSE OF THE REST OF THE EVENING HOURS. HOWEVER... WITH LOW LEVEL SOUTHERLY FLOW (925-850 MB) RAMPING UP BELOW THE COLD DRY SURFACE ALONG WITH INCREASING UPPER DIVERGENCE EXPECT WE WILL SEE A MOISTENING OF THE LOW LEVELS AND PRECIP BEGINNING TO FALL ACROSS THE WESTERN/NORTHWESTERN PIEDMONT AFTER MIDNIGHT TONIGHT. TIMING WISE... THE HRRR IS SHOWING PRECIP MOVING INTO OUR FAR NORTHWEST PIEDMONT FIRST AROUND 07-09Z... THE MOVING INTO THE REST OF OUR NORTHWEST PIEDMONT AND WESTERN PIEDMONT COUNTIES BY 12Z... WITH THE MEASURABLE PRECIP EXPECTED TO BE NEAR RALEIGH BY AROUND DAYBREAK. AS THE PRECIP MOVES INTO THE AREA EXPECT WE WILL LIKELY SEE A BRIEF PERIOD OF SLEET THANKS TO THE DRY LOW LEVEL AIRMASS THE INITIAL PRECIP WILL FALL THROUGH. THEN... WE WILL NEED TO TAKE A LOOK AT OUR SURFACE WET-BULB TEMPS AND THE POTENTIAL FOR FREEZING RAIN... AS THE WARM NOES IS FORECAST TO BE IN EXCESS OF 5 DEGREES C. AND SHOULD KEEP ANY PRECIP IN THE FORM OF RAIN/FREEZING RAIN AFTER THE INITIAL LOW LEVEL AIRMASS IS SATURATED. CURRENT SURFACE TEMPS HAVE LEVELED OFF/INCREASED A BIT WITH THE CLOUD COVER MOVING INTO THE AREA... IN THE MID TO UPPER 30S. HOWEVER... SURFACE DEWPOINTS ACROSS THE AREA IN THE SINGLE DIGITS/TEENS WILL ALLOW FOR THE POTENTIAL TO EVAPORATIVELY COOL OUR TEMPS TO BELOW FREEZING ACROSS PORTIONS OF OUR NORTHWEST/NORTHERN PIEDMONT EARLY TUESDAY MORNING THROUGH AROUND 15Z OR SO. THE BELOW FREEZING SURFACE WET-BULB TEMPS WHEN SUFFICIENT PRECIP MOVES INTO THE AREA IN THE 09-12Z TIME FRAME WILL LOWER TEMPS TO FREEZING OR JUST BELOW FREEZING ACROSS THE COUNTIES LISTED IN OUR WINTER WEATHER ADVISORY. WILL NOT EXPAND THE ADVISORY AT THIS TIME... AS CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME. IF ANY COUNTIES WOULD NEED TO BE ADDED IT WOULD BE GRANVILLE AND VANCE... WITH PERHAPS NORTHERN PORTIONS OF DURHAM COUNTY AND NORTHWESTERN PORTIONS OF CHATHAM COUNTY POSSIBLY CAUSING THE INCLUSION OF THESE COUNTIES. THE REASON FOR NOT ADDING THESE COUNTIES NOW IS WE WILL NEED HEAVY ENOUGH PRECIP TO BE ABLE TO EVAPORATIVELY COOL DOWN TO THE WET-BULB TEMPS. GIVEN THESE AREAS ARE ON THE FRINGE OF SUFFICIENT PRECIP AND SUB-FREEZING WET-BULB TEMPS WILL HOLD OFF FOR NOW. EXPECT ANY FREEZING RAIN THREAT SHOULD END BY MID MORNING AS THE SUPPLY OF COLD DRY AIR AT THE SURFACE WILL BE LIMITED THANKS TO THE SURFACE HIGH PRESSURE CENTER MOVING OFFSHORE... CREATING AN IN- SITU DAMMING EVENT. THUS... MAKING THE FREEZING RAIN EVENT A SELF- LIMITING PROCESS THANKS TO THE LATENT HEATING FROM PHASE CHANGE. ANY ICE ACCRUAL IS EXPECTED TO BE GENERALLY LIMITED TO A TENTH OF AN INCH OR LESS... WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHWEST FORSYTH COUNTY. LOW TEMPS FOR THIS PERIOD HAVE ALREADY OCCURRED ACROSS MOST OF THE COASTAL PLAIN COUNTIES... IN THE MID TO UPPER 20S. TEMPS ACROSS THESE LOCATIONS HAVE RISEN AS CLOUD COVER HAS MOVED INTO THE AREA THIS EVENING... NOW IN THE MID 30S IN GENERAL. LOWS ACROSS THE WESTERN AND NORTHERN PIEDMONT SHOULD OCCUR AS THE PRECIP MOVES INTO THE AREA... WITH LOCATIONS IN THE MIDDLE OF THE CWA GENERALLY REMAINING NEAR STEADY TONIGHT (MID TO UPPER 30S). && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 320 PM MONDAY... TUESDAY... PRECIP WILL BECOME WIDESPREAD ACROSS CENTRAL NC DURING THE FIRST HALF OF THE MORNING. EXPECT WINTRY PRECIP IN THE NW PIEDMONT TO TRANSITION TO MAINLY A COLD RAIN IN THE LATE MORNING. POTENTIAL FOR THE ADVISORY TO BE CANCELED PRIOR TO NOON EXPIRATION IF WARMING OCCURS SOONER OR IS STRONGER THAN EXPECTED. INCREASING DIVERGENCE ALOFT COUPLED WITH INCREASING CONVERGENCE AS A SFC WARM FRONT MIGRATES INLAND FROM THE COAST WILL INCREASE THE LIFT THROUGH THE ENTIRE COLUMN. CONVERGENCE LONG THIS BOUNDARY WILL LEAD TO ENHANCE PRECIP...LEADING TO LOCALLY HEAVY RAINFALL. BEST SHOT OF AXIS OF HEAVY RAIN APPEARS TO EXIST IN VICINITY OF THE HIGHWAY 1 CORRIDOR. EXPECT STORM TOTALS AMOUNTS 1-2 INCHES WITH LOCALIZED AMOUNTS AROUND 2.5 INCHES. TEMPERATURE-WISE...COLD RAIN WILL ENTRENCH THE TRIAD IN AN IN-SITU DAMMING EVENT AS TEMPS WILL STRUGGLE THROUGH THE 30S. THE INLAND ADVANCING WARM FRONT WILL LIKELY CREATE A WIDE TEMP VARIANCE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN. EXPECT TEMPS TO VARY AS MUCH AS 15-20 DEGREES...RANGING THE 40S-50 IN THE TRIANGLE TO THE LOWER 60S EAST OF I-95. LATEST MODEL GUIDANCE HAS COME MORE INLAND WITH HE SFC LOW. IF THIS VERIFIES...POTENTIAL FOR A TEMPERATURE BUST IN VICINITY OF THE TRIANGLE WHERE A TEMPERATURE SWING OF 10-12 DEGREES MAY OCCUR. BASED ON LATEST GUIDANCE...MAY ADJUST TEMPS UP 4-7 DEGREES FROM PREVIOUS FORECAST. TUESDAY NIGHT... FORECAST STILL CHALLENGING THIS PERIOD...DEPENDENT UPON EXTENT OF AVAILABLE SFC BASED INSTABILITY AND EVENTUAL TRACK OF SFC LOW. WIDESPREAD RAIN OR SHOWERS WILL CONTINUE. INCREASING LOW LEVEL JET (AS HIGH AS 60-65KTS OFF THE NAM)WIL PROVIDE INCREDIBLE SHEAR AND STORM RELATIVE HELICITY. FORECAST MODEL SOUNDINGS MAINTAIN A CONDITIONALLY STABLE AIR MASS WITH BEST INSTABILITY ALOFT. EXCEPTION IS THE NAM WHICH SUGGEST THAT SFC BASED INSTABILITY MAY OCCUR OVER OUR FAR SE COUNTIES FOR A FEW HOURS LATE TUESDAY NIGHT (10 PM - 4 AM). BASED ON THE MODEL TREND OF A SFC LOW TRACK A LITTLE FARTHER INLAND...SOME POTENTIAL FOR A SFC BASED THUNDERSTORM TO OCCUR WITH A SMALL THREAT FOR A SEVERE STORM WITH DAMAGING WIND GUSTS OR A BRIEF TORNADO THE MAIN SEVERE WEATHER THREAT. TEMPS TUESDAY NIGHT WILL HOLD STEADY OR SLOWLY RISE ACROSS MOST LOCATION EXCLUDING THE NW PIEDMONT WHERE TEMPS WILL HOLD STEADY. TEMPS IN THE SANDHILLS AND COASTAL PLAIN MAY RISE OR HOLD STEADY IN THE LOW-MID 60S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 325 PM MONDAY... FOR WED/WED NIGHT: MODELS ARE IN GOOD AGREEMENT ON PLACING THE PRIMARY SURFACE LOW NEAR NYC WED MORNING AND THE SECONDARY WEAKER LOW OVER THE VA TIDEWATER... WHICH BOTH CONSOLIDATE INTO A SINGLE LOW OVER MAINE BY DAY`S END. THE SOUTHERN STREAM PORTION OF THE STORM SYSTEM WILL BE WEAKENING AS IT LIFT NORTHEASTWARD THROUGH NC FROM MID MORNING THROUGH EARLY AFTERNOON... BUT IT WILL STILL BE QUITE POTENT INDUCING STRONG FORCING FOR ASCENT AS IT MAINTAINS A NEGATIVE TILT. THE MID-UPPER LEVELS ACCORDING TO FORECAST SOUNDINGS WILL DRY OUT QUITE A BIT IN THE MORNING AS A DRY SLOT PUNCHES IN FROM THE SOUTH... SUGGESTING A TRANSITION TO PATCHY DRIZZLE (OR PERHAPS A LITTLE FREEZING DRIZZLE IN THE FAR NW CWA WHERE SURFACE WET BULB TEMPS WILL BE DROPPING TO AROUND 32F) AS THE COLDER AIR ARRIVES POST-FRONT... WITH THE LOWEST 4 KM OR SO STAYING SATURATED. A SLUG OF DPVA ASSOCIATED WITH THE NORTHERN STREAM PORTION OF THE MID LEVEL LONGWAVE TROUGH SWINGS THROUGH NW NC WED AFTERNOON ATTENDING A DEFORMATION ZONE ALOFT... HOWEVER THESE TOO SHOULD BE WEAKENING AND DON`T APPEAR TO PROVIDE ENOUGH DEEP LAYER LIFT TO RE- SATURATE THE AIR ABOVE -10C. AS SUCH... BELIEVE THAT A FEW WET FLAKES WILL BE POSSIBLE ACROSS THE NW AND FAR NRN PIEDMONT WED AFTERNOON AS THE COLUMN COOLS... BUT IT SHOULD BE INCONSEQUENTIAL GIVEN THE BRIEF WINDOW OF OPPORTUNITY AND LIMITED MOISTURE ALOFT. PASSAGE OF A WEAK POST-FRONTAL SURFACE TROUGH WED AFTERNOON WILL SWING WINDS AROUND TO A UNIFORMLY NW DIRECTION... YIELDING CLEARING SKIES BY EARLY EVENING AS DOWNSLOPE FLOW AND DRY AIR ADVECTION TAKES OVER. WITH A TIGHTENING MSLP GRADIENT DUE TO THE STRENGTHENING DEPARTING SURFACE LOW... THESE BRISK NW WINDS DURING THE DAY ARE EXPECTED TO TOP OUT AT 15-20 MPH SUSTAINED WITH GUSTS OVER 30 MPH POSSIBLE AS STRONG 925 MB WINDS NEAR 35 KT MIX DOWN TO THE SURFACE. WED HIGHS ARE APT TO BE VERY CLOSE TO THE MORNING LOWS... WITH PLUNGING THICKNESSES THROUGH THE DAY WITH STEADY COLD AIR ADVECTION CAUSING TEMPS TO FALL SLOWLY THROUGH THE DAY. EARLY DAY HIGHS FROM THE UPPER 30S NW TO LOWER 60S IN THE EASTERN COASTAL PLAIN... FALLING TO THE MID 30S NW TO MID 40S EAST BY LATE AFTERNOON. DEW POINTS WILL FALL INTO THE TEENS TO LOWER 20S OVERNIGHT WITH CLEARING SKIES... BUT THE CONTINUED LOW LEVEL MIXING WILL KEEP TEMPS FROM FALLING TOO LOW... BUT STILL CHILLY WITH LOWS 22-28. LATE DAY WIND CHILLS ARE EXPECTED TO FALL INTO THE 20S OVER THE PIEDMONT... AND INTO THE TEENS TO AROUND 20 AREAWIDE WED NIGHT WITH DIMINISHING WINDS. FOR THU/THU NIGHT: THE CORE OF THE MID LEVEL TROUGH WILL BE WELL TO OUR NE BY THU MORNING... ALTHOUGH BROAD FLAT TROUGHING WILL PERSIST OVER THE EASTERN CONUS AS A VORTEX SPINS OFF CA WITH WEAK LONGWAVE RIDGING IN BETWEEN. SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WSW AND DRIFT OVER THE SRN/CENTRAL APPALACHIANS AND MID- ATLANTIC THROUGH THU NIGHT. EXPECT A DRY AND SUBSIDING COLUMN WITH JUST A FEW HIGH CLOUDS AS ONE LAST WEAK PERTURBATION SWEEPS OVER THE REGION. MAX TEMPS SHOULD BE COMPARABLE TO YESTERDAY GIVEN A SIMILAR AIR MASS WITH SIMILAR (PERHAPS A BIT HIGHER) PREDICTED THICKNESSES. HIGHS 38-45. MOSTLY CLEAR AND CONTINUED COLD THU NIGHT. LOWS 22-27 LOOK GOOD. FOR FRI THROUGH MON: THE SRN STREAM PORTION OF THE SURFACE HIGH WILL MERGE WITH THE POLAR HIGH TO BE CENTERED OVER MAINE/SW QUEBEC AND NOSE TO THE SSW THROUGH CENTRAL NC FRI THROUGH SAT... AS THE MID LEVEL FLOW OVER THE CENTRAL/ERN CONUS FLATTENS. AN INVERTED TROUGH IS EXPECTED TO FORM ALONG THE SOUTHEAST COAST OVER THE WEEKEND... AND THE ENHANCED ONSHORE-DIRECTED LOW LEVEL FLOW SHOULD PULL INCREASING LOW LEVEL ATLANTIC MOISTURE INTO NC... RESULTING IN INCREASING CLOUDS AS WE HEAD THROUGH SUNDAY. THE MID LEVEL LOW OFF CA LATE IN THE WEEK OPENS UP AND WEAKENS THEN HEADS EASTWARD... AND AS THIS BROAD TROUGH APPROACHES NC FROM THE WEST LATE SUN THROUGH MON... EXPECT A TREND TO MOSTLY CLOUDY SKIES AND A CHANCE OF RAIN AS THE OLD FRONT HEADS NORTHWARD TOWARD NC AS A WARM FRONT. EXPECT A GRADUAL RECOVERY IN TEMPS THROUGH THIS PERIOD... STAYING BELOW NORMAL HOWEVER. HIGHS IN THE 40S TO NEAR 50 FRI/SAT... CLIMBING TO THE 50S TO NEAR 60 FOR SUN/MON. -GIH && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 115 AM TUESDAY... 24 HOUR TAF PERIOD: THE MOST TREACHEROUS CONDITIONS FOR THE TAFS WILL BE IN THE TRIAD AS A POTENT STORM SYSTEM MOVES IN FROM THE SOUTHWEST. NO RAIN OBSERVED YET AT KINT AND KGSO DESPITE RADAR RETURNS ON THE 0.5 DEGREE ELEVATION ANGLE. THIS IS OWING TO VERY DRY AIR IN THE LOWER LEVELS WHICH WILL TAKE A WHILE TO OVERCOME BEFORE PRECIPITATION BEGINS IN THE TRIAD. AS EVAPORATIVE COOLING OCCURS IN THE LOW LEVELS TEMPERATURES WILL COOL TO NEAR FREEZING AND A PERIOD OF FREEZING RAIN IS POSSIBLE AT KINT AND KGSO BEGINNING AROUND 9Z THROUGH 14Z OR SO BEFORE WARM AIR ADVECTION CAUSES TEMPERATURES TO RECOVER. AT THIS TIME FREEZING RAIN IS EXPECTED TO GIVE WAY TO AN EXTENDED PERIOD OF LIGHT TO MODERATE RAIN...WITH POCKETS OF HEAVIER PRECIPITATION THROUGH THE END OF THE TAF PERIOD. ALREADY MVFR CONDITIONS IN THE TRIAD ARE EXPECTED TO FURTHER DETERIORATE TO IFR/LIFR AND MOST LIKELY WILL REMAIN IN THE TANK THROUGH THE PERIOD WITH CEILINGS LESS THAN 1000 FEET AND VISIBILITIES MAINLY IN THE MVFR RANGE. CONDITIONS AT THE REMAINING TAF SITES WILL BE SIMILAR BUT WITHOUT THE PERIOD OF FREEZING RAIN AT THE ONSET AS TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE PERIOD. ANOTHER CONCERN AT ALL TAF LOCATIONS WILL BE LOW LEVEL WIND SHEAR THAT IS EXPECTED TO PICK UP JUST AFTER SUNRISE...NEAR 14Z. LIGHT EAST OR NORTHEASTERLY WINDS IN THE LOW LEVELS WILL RAPIDLY INCREASE TO 35 TO 40 KNOTS OUT OF THE SOUTHEAST NEAR 2 KFT. WHILE THE SEVERITY OF THE LLWS WILL DECREASE AFTER 00Z WEDNESDAY...LLWS WILL STILL BE A CONCERN THROUGH THE END OF THE TAF PERIOD WITH THE EXCEPTION OF KRWI WHERE THE THREAT WILL END EARLIER AS SURFACE WINDS SHOULD BE STRONGER AND NEAR UNIDIRECTIONAL TO HELP MITIGATE SHEAR POTENTIAL. LONG TERM: A SECOND STORM SYSTEM WILL FOLLOW RIGHT BEHIND THE FIRST WHICH WILL CARRY INTO WEDNESDAY BEFORE CLEARING OUT WEDNESDAY NIGHT. CONDITIONS SHOULD BE PREDOMINATELY VFR THEREAFTER UNTIL EARLY NEXT WEEK WHEN THE NEXT SYSTEM APPROACHES. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 2 AM TO NOON EST TUESDAY FOR NCZ007- 021>024-038-039. && $$ SYNOPSIS...WSS NEAR TERM...BSD SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1240 AM CST TUE NOV 26 2013 .UPDATE... ISSUED AT 1240 AM CST TUE NOV 26 2013 NO MAJOR UPDATES REQUIRED TO THE FORECAST FOR THE OVERNIGHT HOURS. ADDED A MENTION OF FLURRIES WESTWARD TO INCLUDE NEARLY ALL OF CENTRAL NORTH DAKOTA TO THE JAMES RIVER BASIN FOR THE OVERNIGHT HOURS. MINIMUM TEMPERATURES WILL DEPEND GREATLY ON SKY COVER WITH CLEAR SKIES ALLOWING RADIATIONAL COOLING AND CLOUD COVER KEEPING TEMPERATURES STEADY OR PERHAPS RISING A TAD. EXPECTING VARIABLE CLOUDINESS OVERNIGHT...AND SOME AREAS INDICATED NEARLY REACHING THE FORECAST MIN TEMPERATURES IN CLEAR SKIES. LOWERED MIN TEMPS JUST A TAD TO ACCOUNT FOR PATCHY CLOUDS/CLEARING. UPDATE ISSUED AT 958 PM CST MON NOV 25 2013 NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. ONLY ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 707 PM CST MON NOV 25 2013 LOW CLOUDS WILL CONTINUE PRIMARILY ALONG AND EAST OF THE MISSOURI RIVER TONIGHT. FURTHERMORE...BOUNDARY LAYER WINDS ARE FORECAST TO REMAIN AROUND 30 KNOTS EAST OF HIGHWAY 83 THROUGH 12Z TUESDAY. GIVEN THE COMBINATION OF LOW CLOUDS AND TURBULENT BOUNDARY LAYER FLOW...ADJUSTED OVERNIGHT LOWS UP BY TWO CATEGORIES...MAINLY EAST OF HIGHWAY 83. HIGH PRESSURE NOSING INTO WESTERN NORTH DAKOTA WILL LIKELY CLEAR OUT THE CLOUDS WEST AFTER MIDNIGHT AND ALLOW TEMPERATURES TO RADIATE INTO THE SINGLE DIGITS WEST OF HIGHWAY 85 BY TUESDAY MORNING. THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 320 PM CST MON NOV 25 2013 A STRONGER SURGE OF COLD AIR ADVECTION WILL PUSH SOUTH INTO NORTH DAKOTA OVERNIGHT. AFTERNOON OBS AND REFLECTIVITY NEAR ROLLA...AND LIGHT QPF SCATTERED ALONG THE EASTERN FRINGES OF THE FORECAST AREA IN SOME SHORT RANGE MODELS...HAVE PROMPTED INCLUSION OF FLURRIES FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY TONIGHT. A FEW AFTERNOON OBS AT MINOT AND TIOGA...SUGGESTIVE OF FREEZING DRIZZLE/UNKNOWN PRECIP...ARE ACTUALLY THE RESULT OF EXISTING SNOW BEING BLOWN NEAR THE WEATHER SENSOR. HAVE INCREASED OVERNIGHT CLOUD COVER BASED ON AFTERNOON TRENDS AND ROBUST LOW LEVEL RH EVIDENT ON THE RAP MODEL. LOWS SHOULD BE IN THE SINGLE DIGITS TO AROUND 10 DEGREES SOUTH. TUESDAY WILL BE THE COLDEST DAY OF THE COMING WEEK...WITH HIGHS IN THE TEENS TO LOWER 20S SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 320 PM CST MON NOV 25 2013 LATEST EXTENDED SUITE CONTINUES TO SHOW AN ACTIVE PERIOD IN TERMS OF SUCCESSIVE DRY FRONTAL SYSTEMS SLIDING THROUGH. THE NEXT POTENTIALLY SIGNIFICANT SYSTEM MAY OCCUR MONDAY AND BEYOND. A PROGRESSIVE PATTERN BEGINS THE LONG TERM WITH A WAVERING BAROCLINIC ZONE SHIFTING FROM WEST TO EAST TUESDAY NIGHT AS WARM AIR ADVECTION COMMENCES. A WEAK COLD FRONT FOLLOWS FOR WEDNESDAY/ WEDNESDAY NIGHT WITH A RETURN TO COLD AIR ADVECTION INTO EARLY THURSDAY. NEUTRAL ADVECTION TO WEAK WARM AIR ADVECTION RESUMES FRIDAY INTO SATURDAY. THE ONLY SUFFICIENT LIFT FOR MEASURABLE PRECIPITATION DURING THIS TIME WOULD BE CONFINED TO THE TURTLE MOUNTAINS WEDNESDAY AND FRIDAY NIGHT. HAVE COLLABORATED WITH OUR EASTERN OFFICE AND INCORPORATED A SLIGHT CHC OF SNOW IN THE FAR NORTHEAST. ANY SNOW ACCUMULATION WOULD BE MINIMAL AT BEST. THE NEXT SYSTEM TO AFFECT WESTERN AND CENTRAL NORTH DAKOTA SHOWS SIGNS OF LIGHT PRECIPITATION BREAKING OUT VIA WARM AIR ADVECTION PROCESSES SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER IT APPEARS THE BULK OF PRECIPITATION WOULD BE IN THE FORM OF SNOW MONDAY INTO MONDAY NIGHT. A DRY SLOT MAY FOLLOW FOR TUESDAY. STILL A LOT OF UNCERTAINTY THIS FAR OUT AND WILL CONTINUE TO MONITOR FUTURE MODELS RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1240 AM CST TUE NOV 26 2013 MVFR CIGS WILL CONTINUE GENERALLY ALONG AND EAST OF A LINE FROM KISN-KBIS TONIGHT. CONDITIONS WILL GRADUALLY IMPROVE TO VFR FROM WEST TO EAST TUESDAY MORNING. VFR CONDITIONS ARE FORECAST OVER KISN/KDIK/KMOT/KBIS BY TUESDAY AFTERNOON...AND AT KJMS LATE AFTERNOON. NORTHWEST WINDS WILL CONTINUE THROUGH TUESDAY AFTERNOON...THEN BECOME LIGHT AND TURN TO THE SOUTHEAST BY/DURING TUESDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...RP KINNEY LONG TERM...KS AVIATION...JV
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1121 PM CST MON NOV 25 2013 .UPDATE... 06Z AVIATION DISCUSSION BELOW. .PREVIOUS UPDATE DISCUSSION... STRATUS SHIELD CONTS TO SLIDE SE ACROSS NERN PART OF SOUTH DAKOTA OVERNIGHT...CREATING A DIFFICULT FORECAST FOR OVERNIGHT LOWS. TEMPS UNDER THE CLOUD SHIELD HAVE NOT FALLEN OFF GREATLY FROM THE AFTERNOON READINGS...WITH TEMPS AOA 30 DEGREES AND HOLDING STEADY. FURTHER SW...CLEAR SKIES ARE ENABLING TEMPS IN THE FAR SW CWA TO FALL...ALBEIT SLOWLY...BUT FALLING NONE THE LESS. THE PROBLEM ARISES WHEN TRYING TO TIME THE BACK EDGE OF THE CLOUD SHIELD AS IT HAS PUSHED INTO NRN ND ATTM WITH TEMPS ACROSS SRN CANADA IN THE SINGLE DIGITS ABOVE ZERO. SENT OUT EARLIER UPDATE TO SLOW THE TEMP FALL ACROSS THE CWA...AND RAISE LOWS ABOUT A CATEGORY ACROSS THE NE. ALSO MANUALLY ADJUSTED THE HOURLY TEMP GRIDS...KEEPING TEMPS UP THROUGH 10Z OR SO...THEN IN ANTICIPATION OF CLEARING LINE...ALLOWED TEMPS TO FALL TO FORECAST LOWS AROUND 13Z TO 14Z. ISOLD FLURRIES ARE STILL BEING REPORTED ACROSS ERN SECTIONS OF ND...AND STILL SEEMS PRUDENT TO KEEP THEM IN ONGOING FCST. ALSO TWEAKED SKY GRIDS TO BETTER MATCH CURRENT CLOUD SHIELD LOCATION AND WINDS ARE ALSO STAYING UP JUST A BIT. UPDATED ZONE FORECAST SENT OUT EARLIER. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT LEADING EDGE OF THE STRATUS/STRATOCUMULUS DECK IS FIRMLY IN PLACE ACROSS THE EASTERN CWA...WITH A MASSIVE EXPANSION BACK TO THE NORTH INTO CANADA. MAIN FORECAST ISSUES OVERNIGHT WILL BE CLOUD COVER AND THE ONSET OF STRONGER COLD AIR ADVECTION. RUC13 900-850 MB RH HAS A VERY GOOD HANDLE ON CURRENT STRATUS OVER THE REGION SO USED THAT AS A FORECAST FOR THE OVERNIGHT PERIOD. IT BASICALLY SHOWS THE STRATUS SLOWLY OOZING SOUTHWEST ACROSS SOUTH DAKOTA THROUGH 12Z TUESDAY. HAVE INCREASED SKY COVER FROM PREVIOUS FORECAST AND MAY NEED TO BE BEEFED UP MORE FOR EVENING UPDATES. WITH ADDITIONAL WEAK SHORTWAVE ENERGY MOVING SOUTH OVER THE AREA LATE TONIGHT AND THE STRONGER COLD AIR ADVECTION...SEE NO REASON WHY CLOUDS WOULD BREAK UP OR CEASE TO MOVE ANY FURTHER SOUTH/SOUTHWEST INTO TUESDAY MORNING. LEFT IN THE MENTION OF FLURRIES FOR THE EASTERN CWA LATE TONIGHT THROUGH TUESDAY MORNING IN ASSOCIATION WITH THE WEAK SHORTWAVE ENERGY. CURRENT OBS ACROSS NORTHEAST ND AND SOUTHERN CANADA SHOW -SN WITH VSBYS GENERALLY ABOVE 6SM IN ASSOCIATION WITH THE WEAK WAVE. WITH THE ONSET OF COLDER AIR ALOFT ON TUESDAY...WILL SEE HIGH TEMPS SEVERAL DEGREES COLDER THAN MONDAY. READINGS WILL BE IN THE TEENS TO MID 20S ACROSS THE CWA. SURFACE HIGH THEN MOVES THROUGH THE AREA TUESDAY NIGHT WHICH SHOULD CLEAR THE SKIES AND PROVIDE FOR A PERIOD OF LIGHT WINDS. ALTHOUGH THE RIDGE AXIS IS PRETTY NARROW AND A QUICK MOVER...SO BY 12Z WEDNESDAY MUCH OF THE CWA IS ALREADY UNDER SOUTHERLY SFC WIND FLOW. NOT AN IDEAL RADIATIONAL COOLING SETUP...BUT WILL STILL GET PRETTY COLD NONETHELESS. WILL BE AROUND 0 DEGREES ACROSS THE EASTERN CWA WITH FAVORED COLD SPOTS PERHAPS SNEAKING BELOW ZERO. HIGHS ON WEDNESDAY WILL REBOUND SOMEWHAT AS 925MB TEMPS BEGIN TO WARM ON THE BACKSIDE OF THE RETREATING SFC HIGH. BREEZY WINDS WILL DEVELOP SO THERE WILL BE DECENT MIXING. HIGHS WILL REMAIN BELOW NORMAL THOUGH AS THE OVERALL PATTERN REMAINS COLD. .LONG TERM...THURSDAY THROUGH SUNDAY NORTHWEST FLOW ALOFT WILL BE THE PREDOMINATE UPPER PATTERN THROUGH MOST OF THE LONG TERM PERIOD...BUT A PATTERN CHANGE DOES SEEM TO BE ON THE HORIZON. A SHORTWAVE TROUGH DROPPING OUT OF CANADA WILL INFLUENCE THE REGION FOR THE FRIDAY/SATURDAY TIME FRAME...HOWEVER MOST OF THE FORCING APPEARS TO REMAIN NORTH OF OUR CWA...AND MODEL MOISTURE PROFILES REMAIN FAIRLY DRY AT THIS POINT. DECENT WARM AIR ADVECTION AHEAD OF THAT WAVE COULD CAUSE SOME PTYPE ISSUES IF PRECIPITATION WERE TO MATERIALIZE OVER OUR CWA SATURDAY. ALTHOUGH MODELS VARY ON THE STRENGTH OF THE WARM PUSH...850 MB TEMPERATURES DO RISE ABOVE 0 C...WITH THE GFS ADVERTISING AS HIGH AS 6 OR 7 C ACROSS OUR SOUTHERN CWA. EITHER WAY...CONTINUED WITH THE DRY ALLBLEND FORECAST FOR NOW. BY SUNDAY WEAK RIDING APPEARS TO BE OVER THE NORTHERN PLAINS...BUT IT ONLY PRECEDES A MORE SIGNIFICANT UPPER LOW MOVING INTO THE PACIFIC NORTHWEST. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS MVFR STRATUS DECK CONTS TO RESIDE OVER THE NERN PART OF THE CWA...WITH KMBG/KABR/KATY ALL REPORTING OVC CONDS. LOOK FOR THE EDGE OF THE SHIELD TO CREATE SCT-BKN CONDS FOR THE KPIR TERMINAL BY 08Z. BACK EDGE OF CLOUD DECK LOOKS TO MOVE INTO THE NRN TERMINAL LOCATIONS AOA 13Z...AND INTO KATY BY 15Z. GUSTY NW WINDS WILL WILL AFFECT ALL TERMINAL LOCATIONS THROUGH 14Z BEFORE BEGINNING TO DIMINISH. ONCE SKIES CLEAR...LOOK FOR GOOD VFR CONDS THROUGH THE REMAINDER OF THE VALID FORECAST PERIOD. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...HINTZ SHORT TERM...TMT LONG TERM...SERR AVIATION...HINTZ WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1144 PM CST MON NOV 25 2013 .AVIATION... THE BACK EDGE OF THE LOW CLOUD DECK WAS EDGING SOUTHWARD AT 20 MPH AND SHOULD PASS BOTH KLBB AND KCDS NEAR 08Z TONIGHT. UNTIL THEN...KLBB WILL HAVE THE BIGGEST CHANCE OF IFR AND MAYBE EVEN LIFR CONDITIONS WHILE KCDS APPEARS TO HAVE SLOWLY INCREASING MVFR CEILINGS ALREADY. KLBB ALSO WILL STILL EXPERIENCE LIGHT FREEZING DRIZZLE AND PROBABLY AT MOST A LIGHT FOG UNTIL ABOUT 08Z. THERE STILL WILL BE A NON-ZERO RISK FOR SURFACE OBSCURATION FROM FOG LATER TONIGHT AT KCDS MAINLY BUT TRENDS DO NOT APPEAR TO SUPPORT THIS TO ANY AMOUNT LARGE ENOUGH FOR TAF INCLUSION. OTHERWISE... TREND TOWARDS VFR ON TUESDAY ARE CLEAR. RMCQUEEN && .PREV DISCUSSION... /ISSUED 701 PM CST MON NOV 25 2013/ UPDATE... ISSUED A WINTER WEATHER ADVISORY THROUGH THE EVENING AS AN AREA OF LIGHT FREEZING DRIZZLE AND FOG WAS SPREADING SOUTHWARD THROUGH MOST OF THE AREA. ALSO EXPECT FLURRIES. MOST SOLUTIONS DIMINISH THE SHALLOW LIFT AND THIN THE NEAR-SURFACE MOIST LAYER AROUND MIDNIGHT. RMCQUEEN PREV DISCUSSION... /ISSUED 547 PM CST MON NOV 25 2013/ AVIATION... A LOW STRATUS LAYER BEHIND THIS AFTERNOONS COLD FRONT WAS EDGING SOUTHWARD TOWARDS KLBB EARLY THIS EVENING AND SHOULD MAKE IT INTO KLBB VERY SHORTLY AFTER 00Z. LATEST RAP SOUNDINGS STEADILY LOWER CEILING AT KLBB TO LIFR LEVELS EARLY THIS EVENING...THOUGH THE HRRR RUN REVEALS LESS CERTAINTY. WE HAVE CONTINUED PREVIOUS IDEA OF AN LIFR LAYER THIS EVENING INTO KLBB...AND EVEN ADDED TEMP LIGHT FOG AND FREEZING DRIZZLE BASED ON UPSTREAM REPORTS. THERE IS ALSO A LOW RISK OF A HARD DROP IN VISIBILITY AS THIS IS EMANATING OFF THE HEAVY SNOW FIELD...THOUGH NOT EXPLICIT FOR KLBB IN ANY GUIDANCE AT THE MOMENT. FOR KCDS...THE CURRENT IFR/LIFR CIG SHOULD HOLD FOR SEVERAL HOURS BEFORE BREAKING...AT LEAST BASED ON SHORT RANGE MODEL TRENDS. UNCERTAIN FOR KCDS IS IF FOG COULD REDEVELOP LATER TONIGHT PER RAP SURFACE HUMIDITY PROGS. WILL STUDY FURTHER FOR 06Z CYCLE. CONDITIONS EXPECTED TO BE ALL VFR TUESDAY. RMCQUEEN PREV DISCUSSION... /ISSUED 300 PM CST MON NOV 25 2013/ SHORT TERM... UPPER LEVEL LOW WHICH HELPED FEED MOISTURE IN FOR THE WEEKEND WINTER WEATHER STORM WAS OVER THE PANHANDLE AT MID DAY. THE LOW CENTER WILL MAKE AN INTERESTING TRAJECTORY DIGGING SOUTHWARD THIS EVENING AND MAKING IT INTO THE TX HILL COUNTRY BY TUESDAY MORNING BEFORE EJECTING NORTHEASTWARD AS IT PHASES WITH A MAIN STREAM DIVING THROUGH MANITOBA THIS AFTERNOON. THIS WILL RESULT IN NORTHERLY FLOW AND MUCH DRIER CONDITIONS SETTING IN. LOWS TONIGHT WILL BE TRICKY AS SKIES ARE EXPECTED TO CLEAR NW TO SE AROUND SUNRISE TUESDAY MORNING. GIVEN THE PROXIMITY OF THE UPPER LOW...WE MAY SEE A FEW FLURRIES OVERNIGHT WINDS SHOULD REMAIN UP AROUND 10 KTS AND THOUGH WIDESPREAD SNOWFALL REMAINS ON THE GROUND...COMBINATION OF SPEEDS AND DOWNSLOPE TRAJECTORY SHOULD KEEP FOG THREAT TO A MINIMUM THOUGH GIVEN THE SNOW-PACK...WILL GO AHEAD AND MENTION PATCHY FOG NORTHWEST. SUNNY AND MUCH WARMER TUESDAY. LONG TERM... HIGH AMPLITUDE RIDGE IN PLACE ACROSS THE ROCKIES TO BEGIN THE EXTENDED PERIOD TUESDAY NIGHT AND WEDNESDAY. SHOULD BE RATHER COLD AGAIN OVER DEEPER SNOW-PACK SRN PANHANDLE WITH TEMPS AGAIN IN THE TEENS. IF WINDS ARE LIGHT ENOUGH...COULD SEE SOME SINGLE DIGITS. 40S AREAWIDE FOR HIGHS WEDNESDAY...AND THEN 50S ON THURSDAY AS FLAT UPPER RIDGE AXIS MOVES EAST OVER THE CENTRAL AND SOUTHERN PLAINS. MAY BE PUSHING 55-60 DEGREES SOUTH BY FRIDAY AS SURFACE LEE TROUGH DEEPENS FROM ERN CO INTO NERN NM AND WEST TEXAS. NEXT SYSTEM OF INTEREST IS POS TILTED OPEN WAVE THAT WILL APPROACH THE AREA OVER THE WEEKEND. SHOULD BEGIN TO SEE SOME MOISTURE RETURN LATE FRIDAY AND SATURDAY AS SOUTHERLY WINDS INCREASE...LIKELY SOME LOW CLOUDS CENTRAL AND EAST SECTIONS. GFS FOR NOW KEEPS SHOWERS EAST OF THE AREA. MAY SEE FRONT INTO AREA ON SUNDAY. PROGRESSIVE NATURE OF SYSTEM LIKELY MEANS A DRY FRONT...AND ONLY SLIGHT COOL-DOWN. BOTH GFS AND PREV ECMWF ADVERTISING BIG PATTERN CHANGE WEDNESDAY OF NEXT WEEK (DEC. 4) WITH CRASHING HEIGHTS OVER THE WESTERN CONUS. IF SOME SEMBLANCE OF THIS PATTERN IS REALIZED...COULD TURN MUCH COLDER AROUND THIS TIME...WITH WINTER WEATHER POSSIBLY MAKING A RETURN. DOES BEAR WATCHING. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 14 36 17 39 23 / 10 0 0 0 0 TULIA 19 38 18 39 23 / 10 0 0 0 0 PLAINVIEW 22 41 20 44 25 / 10 0 0 0 0 LEVELLAND 21 45 20 44 25 / 10 0 0 0 0 LUBBOCK 23 45 22 48 27 / 10 0 0 0 0 DENVER CITY 23 46 23 48 25 / 10 0 0 0 0 BROWNFIELD 23 46 22 48 25 / 10 0 0 0 0 CHILDRESS 23 47 24 45 26 / 10 0 0 0 0 SPUR 26 48 22 48 27 / 10 0 0 0 0 ASPERMONT 25 49 26 48 29 / 10 10 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING ZONES: TXZ021>037-039>042. && $$ 99/99/05
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1135 PM EST MON NOV 25 2013 .SYNOPSIS... STORM SYSTEM WILL MOVE FROM THE GULF COAST TONIGHT INTO EASTERN NC/VA BY WEDNESDAY MORNING...AND FINALLY NORTH INTO QUEBEC BY WED NIGHT. THIS SYSTEM WILL BRING A POTPOURRI OF WEATHER THROUGH WED NIGHT. HIGH PRESSURE ENTERS FROM THE SOUTHWEST BY THURSDAY...AND STICKS AROUND INTO SATURDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 1045 PM EST MONDAY... QUICK UPDATE TO START THE ADVISORY RIGHT NOW OVER THE WEST SINCE GETTING REPORTS OF SNOW ACCUMULATING ON ROADS ACROSS THE FAR SW. LEAVING THE REMAINDER FROM ALONG THE BLUE RIDGE EAST STARTING AT 2 AM. AS OF 825 PM EST MONDAY... MID/LOW LEVEL DRY AIR PER EVENING SOUNDINGS AND LATEST OBS HAS CONTINUED TO KEEP PRECIP FARTHER TO THE WEST THIS EVENING WITH MOST PRECIP ON RADAR ALOFT AND JUST GOING TO SLOWLY MOISTEN THE COLUMN ATTM. IN ADDITION THE LOW LEVEL FLOW REMAINS RATHER WEAK AND SW JUST ABOVE THE SURFACE MAKING FOR LIMITED ISENTROPIC LIFT AS THE BEST JET SUPPORT INCLUDING AXIS OF HIGHER DEWPOINTS LINGERS ACROSS THE TN VALLEY. BOTH THE LATEST RAP AND HRRR HAVE DELAYED THE ONSET OF SIGNIFICANT PRECIP UNTIL AFTER MIDNIGHT FOR THE MOST PART WEST AND UNTIL THE EARLY MORNING HOURS OUT EAST. SINCE THIS LOOKS IN LINE WITH THE LATEST TRENDS...HAVE DELAYED ONSET OF POPS ACROSS THE REGION FOR COUPLE HOURS BEFORE THINGS REALLY MOISTEN AND PRECIP QUICKLY INCREASES ESPCLY BLUE RIDGE AND ACROSS THE SOUTH AFTER MIDNIGHT. EVENING RAOBS AND SURFACE OBS INDICATE STILL LOTS OF ROOM FOR WET BULB COOLING ALTHOUGH TREND OUT WEST HAS BEEN FOR DEWPOINTS TO RISE WITHOUT MUCH COOLING AS PRECIP EVAPORATES BEFORE REACHING THE SURFACE. THIS SUPPORTS KEEPING A MIXED BAG BUT A LITTLE MORE SNOW WEST AT THE ONSET WITH SOME CHANCE OF SNOW/SLEET EAST THEN MOSTLY FZRA/SLEET. ADJUSTED TEMPS DOWN SOME FOR CURRENT READINGS WITH MOST LIKELY NOT DROPPING TOO MUCH MORE UNTIL HEAVIER PRECIP ARRIVES. MAIN ADJUST TO HEADLINES WAS TO EXTEND THE GOING ADVISORY LONGER INTO THE AFTERNOON ON TUESDAY FOR AMHERST/BOTETOURT COUNTIES GIVEN FORECAST SOUNDINGS SHOWING TEMPS UNABLE TO GET MUCH ABOVE FREEZING UNTIL LATE IN THE DAY. THIS MAY ALSO BE THE CASE ON THE NORTH SIDE OF HIGHWAY 460 IN ROANOKE AND MONTGOMERY COUNTIES BUT HELD THOSE AREAS AT A NOON EXPIRATION FOR NOW GIVEN POTENTIAL FOR THAT AREA TO SEE WARMING FROM HEAVIER RAINFALL THROUGH THE WARM LAYER SOONER. PREVIOUS DISCUSSION AS OF 250 PM EST MONDAY... DURING THIS TIME PERIOD WILL BE DEALING WITH NUISANCE WINTER WX WHERE PRECIP ARRIVES INTO THE NC MTNS/FAR SW VA BEFORE MIDNIGHT OVERSPREADING THE REGION BY DAWN. SUNSHINE CAME OUT TODAY OVER MOST OF THE AREA ALLOWING TEMPS TO CLIMB ABOVE FREEZING AND AROUND 40 IN SOUTHSIDE VA/FAR SW VA. DEWPOINTS HOWEVER ARE TANKED IN THE SINGLE DIGITS. HENCE LIES THE PROBLEM TONIGHT. UPSTREAM CLOUDS ALREADY POURING BACK IN AND THIS MAY HELP IN TERMS OF NOT ALLOWING TEMPS TO DROP TOO FAR AFTER SUNSET AS CLOUDS ACT AS A BLANKET. THEN...AS THE PRECIP ARRIVES...GIVEN THE DRY AIR IT MAY TAKE AN HOUR OR TWO TO SATURATE THE LOW LVLS BUT ONCE IT DOES...THE TEMP/DEWPOINT PROFILE WILL HEAD TOWARD CRITICAL LEVELS FOR WINTER PRECIP. AT THE ONSET THE TEMPS SHOULD BE COLD ENOUGH FOR SLEET OR SNOW THEN CHANGE QUICKLY TO FREEZING RAIN AS STRONG SOUTH TO SOUTHWEST FLOW BRINGS A WARM NOSE INTO THE MTNS AFTER MIDNIGHT AND REACHING OUR NRN CWA BY MID MORNING. WITH INSITU WEDGE AND SFC WET BULBING TO AT OR BELOW ZERO WITH WARM NOSE...FREEZING RAIN WILL BECOME AN ISSUE. GROUND HAS TURNED COLDER AS EVIDENCE BY SOIL TEMPS IN THE LOWER TO MID 30S. THERE WILL BE A LIGHT ACCUMULATION OF SLEET OR SNOW AT THE ONSET...LESS THAN AN INCH...THEN QUICKLY CHANGING TO FZRA WITH GLAZING EXPECTED ALONG TREE/POWERLINES AND METAL OBJECTS FIRST THEN BRIDGES/OVERPASSES. BASED ON RAINFALL RATE AND WARM AIR ALOFT THE ACCRETION OF ICE WILL BE IN A 2-4 HOUR WINDOW AS THE BETTER LIFT TAKES PLACE AFTER 12Z...ALLOWING THE RATES TO INCREASE AND DRAG DOWN WARMER AIR. MODERATE TO HEAVIER RAINFALL USUALLY DOES NOT STICK TO ROADS VERY WELL WHEN SFC TEMPS ARE EXPECTED TO BE NEAR FREEZING. NEED MORE LIKE MID TO UPPER 20S OR LOWER. STILL THERE SEEMS TO BE ENOUGH EVIDENCE THAT MOST OF OUR CWA WILL GET AT LEAST A TRACE OF ICE WITH HIGHER AMOUNTS ALONG THE BLUE RIDGE FROM BOONE/BLOWING ROCK NORTH TO BUENA VISTA/AMHERST. ALSO THE ALLEGHANY HIGHLAND SHOULD SEE UP TO 2/10S. IT ONLY TAKES A TRACE OF ICE TO CAUSE TRAVEL PROBLEMS. BASED ON THIS AND COLLABORATION WITH SURROUNDING NWS OFFICES...WE HAVE A WINTER WX ADVISORY OUT FOR THE ENTIRE CWA FOR TONIGHT-MIDDAY/AFTERNOON TUESDAY...ENDING EARLIER IN THE SOUTH. TEMPS THIS EVENING WILL START FALLING SLOWLY THEN DROP A LITTLE MORE ONCE PRECIP ARRIVES ALOFT LEADING TO EVAP COOLING. LOOKING AT LOWS FROM THE UPPER 20S TO AROUND 30...THEN WARMING GRADUALLY TO ABOVE FREEZING DURING THE DAY TUESDAY...FIRST IN THE FAR SW VA/SRN WV AREA OUTSIDE THE WEDGE AND INTO WRN NC MTNS ALONG THE TN BORDER...THEN SOUTHSIDE VA/NW NC PIEDMONT EXPANDING NORTHWARD BY AFTERNOON TO THE NRN BLUE RIDGE. COULD BE A DEAL WHERE SOME VALLEYS ACROSS BATH/ROCKBRIDGE/AMHERST TAKE INTO TUE EVENING...BUT THINK THE WARMER RAIN AND HIGHER RATES TO BRING IT UP. FOR MOST OF US...THE ICE WILL BE MELTED AND GONE BY MIDDAY/EARLY AFTERNOON WITH HIGHS EXPECTED TO BE IN THE MID TO UPPER 30S SOUTH...TO LOWER 30S NORTH. BUT WILL BE DEALING WITH MODERATE TO HEAVY AT TIMES COLD NOVEMBER RAINS. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 340 PM EST MONDAY... GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE NORTHERN AND SOUTHERN BEGINNING TO PHASE TUESDAY NIGHT AND BECOME ONE SYSTEM WEDNESDAY. THE UPPER LEVEL LOW TRACKING ALONG THE GULF COAST WILL OPEN OVER THE TENNESSEE VALLEY AND MERGE WITH THE NORTHERN STREAM TROUGH ENTERING THE OHIO VALLEY BY WEDNESDAY MORNING. THE SURFACE LOW PRESSURE OVER GEORGIA ON TUESDAY EVENING WILL TRACK NORTHEAST ALONG THE LEE SIDE OF THE APPALACHIAN MOUNTAINS EARLY WEDNESDAY MORNING. AS THE NORTHERN STREAM TROUGH BECOMES DOMINATE...A SECONDARY SURFACE LOW IS EXPECTED TO DEVELOP OVER THE VIRGINIA PIEDMONT TUESDAY NIGHT...THEN LIFT TO NEW ENGLAND ON WEDNESDAY. BY WEDNESDAY EVENING...THE SFC LOW WILL BE LOCATED OVER MAINE WITH TRAILING COLD FRONT PUSHING INTO THE ATLANTIC OCEAN. HIGH PRESSURE WILL BE BUILDING ACROSS OUR REGION WEDNESDAY NIGHT INTO THURSDAY. THE RAIN MAY BE HEAVY AT TIMES TUESDAY AFTERNOON INTO WEDNESDAY MORNING. JET DYNAMICS AND LIFT ASSOCIATED WITH PASSING SURFACE AND SHORTWAVES WILL BRING HIGH RAINFALL RATES TO THE AREA. COLDER AIR WILL PUSH INTO OUR REGION TUESDAY NIGHT INTO WEDNESDAY MORNING. RAIN WILL TRANSITION TO SNOW STARTING ALONG THE HIGHER ELEVATION THEN ACROSS THE REST ON WEDNESDAY. MOISTURE WILL PULL OUT OF MOST OF THE AREA WEDNESDAY EVENING INTO WEDNESDAY NIGHT. NORTHWEST UPSLOPE SNOW SHOWERS AND SNOW FLURRIES WILL CONTINUE INTO WEDNESDAY NIGHT INTO THURSDAY. POTENTIAL STORM TOTAL SNOW FOR THE MOUNTAINS WILL LIKELY RANGE FROM 1-4 INCHES TUESDAY NIGHT INTO WEDNESDAY...WITH UPWARDS OF 4 TO 6 INCHES ON WESTERN SLOPES TUESDAY NIGHT INTO WEDNESDAY NIGHT. LIGHTER AMOUNTS OF SNOW EXPECTED GENERALLY LESS THAN INCH IN THE EAST. INCREASING WINDS WILL ACCOMPANY THE UPSLOPE SNOW SHOWERS. STRONG PRESSURE RISES AND COLD AIR ADVECTION ALONG WITH A 45-55KT CROSS BARRIER JET WILL BRING SUSTAIN WINDS OF 20-30 MPH GUSTING TO AROUND 50 MPH FOR COUNTIES ALONG THE BLUE RIDGE...PARTICULARLY THE NORTH CAROLINA HIGH COUNTY AND GRAYSON HIGHLANDS. WIND SPEED WILL BE CLOSE TO ADVISORY LEVELS. WILL HOLD OFF ON ISSUING HEADLINES FOR SNOW AND WINDS FOR NOW TO AVOID CONFUSION WITH ONGOING EVENT. ONE SET OF HEADLINES WILL BE REPLACED BY ANOTHER SET EVERY 6-12 HOURS. PLAN TO HIGHLIGHT THE POTENTIAL IN HWO. AS THIS SYSTEM DEVELOPS AND MATURES OVER THE REGION...EVERYONE SHOULD BE PREPARED FOR RAPIDLY CHANGING CONDITIONS...ESPECIALLY IF YOU ARE TRAVELING ALONG THE EAST COAST THIS WEEK. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 1245 PM EDT MONDAY... LARGE SCALE PATTERN TRANSITIONS TO ZONAL FLOW WITH SURFACE HIGH PRESSURE IN CONTROL THROUGH THE WEEKEND. THIS RESULTS IN SLOWLY MODERATING TEMPERATURES...YET SHOULD REMAIN BELOW SEASONABLE AVERAGES EVEN BY SUNDAY. ALSO THINKING HIGHER CLOUDS WILL BECOME MORE PREVALENT BY SUNDAY WHICH WOULD KEEP HIGHS DOWN SOMEWHAT. LONG TERM MODELS GENERALLY IN AGREEMENT THAT NEXT WEATHER SYSTEM WILL MATERIALIZE IN THE SOUTHERN PLAINS LATE SUNDAY AND THEN QUICKLY APPROACHING THE SOUTHERN APPALACHIANS FROM THE SOUTHWEST ON MONDAY. RIGHT NOW THE 00Z ECWMF IS A LITTLE FASTER THAN THE 12Z GFS AND GIVEN THE GENERALLY ZONAL FLOW PATTERN THIS FASTER IDEA IS FAVORED...ESPECIALLY AS A STRONGER SYSTEM DIGS INTO THE WESTERN U.S. AND EJECTS THIS WAVE OUT ACROSS THE PLAINS AND TOWARDS THE APPALACHIANS. THE HIGH PRESSURE WILL BE WEAKENING AND RETREATING AS THIS SYSTEM APPROACHES BY EARLY MONDAY BUT AIRMASS APPEARS THAT IT WILL MODERATE ENOUGH SO THAT PRECIP TYPE REMAINS JUST RAIN. HOWEVER IT WILL BE WORTH KEEPING AN EYE ON THE TIMING OF PRECIP ARRIVAL AND STRENGTH OF LINGERING HIGH...AS WELL AS HOW LOW INITIAL WET BULB TEMPERATURES ARE WHEN PRECIP ARRIVES. CANT RULE OUT SOME POCKETS OF FREEZING RAIN IF THIS COMES IN OVERNIGHT...BUT AT THIS POINT STILL A LONG WAY OFF. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... AS OF 1130 PM EST MONDAY... BAND OF MIXED SNOW AND SLEET CONTINUES TO PUSH EAST TOWARD THE BLUE RIDGE AND SHOULD BRING SOME -SN TO KBCB/ROA OVER THE NEXT HOUR OR TWO BEFORE COVERAGE BRIEFLY FADES. THIS WILL RESULT IN LOWERING CIGS TO MVFR OVER THE WEST BEFORE MORE SIGNIFICANT MIXED PRECIP ARRIVES WELL AFTER MIDNIGHT. THUS LOOKING AT DETERIORATING FLYING WEATHER AS THE NIGHT WEARS ON WITH WIDESPREAD LOW CIGS AND AT LEAST MVFR VSBYS OVER THE WEST BY DAYBREAK TUESDAY WHEN PRECIP SHOULD TAKE THE FORM OF FREEZING RAIN. FARTHER EAST EXPECTING LYH TO START AS FZRA WITH PERHAPS A BIT OF SN/PL WITH THE INITIAL BATCH. DAN WILL BE BORDERLINE ON FZRA BUT TEMPS SHOULD BE HUGGING 32-33F AT THE SFC SO INCLUDED A HOUR OR TWO OF -FZRA THERE EARLY TUESDAY. WARM NOSE ALOFT TO CHANGE FZRA TO RAIN AT ALL SITES AROUND MIDDAY TUESDAY ALTHOUGH SPOTS LIKE KLWB/KLYH MAY KEEP -FZRA INTO MID OR LATE AFTERNOON. RAIN BECOMES HEAVY AT TIMES TUESDAY AFTERNOON ESPECIALLY AT BCB/ROA/LYH/DAN. WILL EXPECT TO SEE FLUCTUATIONS IN CIGS/VSBYS BASED ON RAINFALL RATES BUT OVERALL SHOULD BE IFR TO LIFR WITH MOUNTAIN OBSCURATIONS LIKELY. WITH THE STRONG SE FLOW ABOVE THE SURFACE WILL ALSO BE SEEING LLWS POTENTIAL AT ALL LOCATIONS THROUGH THE DAY TUESDAY AS LATEST SOUNDINGS INDICATE 35-45 KTS JUST ABOVE THE SURFACE ESPCLY IN THE AFTERNOON. THEREFORE INCLUDED LLWS AT MOST SPOTS FOR STRONG SOUTH TO SE FLOW DEVELOPING RIGHT AFTER SUNRISE ON TUESDAY. MODERATE TO HEAVY RAINFALL CONTINUES TUESDAY NIGHT WITH LOCATIONS ACROSS SE WVA TRANSITIONING BACK TO SNOW BY EARLY WEDNESDAY. THIS WILL KEEP LOW IFR/LIFR CIGS AND MVFR TO IFR VSBYS GOING TUESDAY NIGHT AS THE CORE OF THE LOW PRESSURE SYSTEM TRACKS ACROSS THE AREA. RAIN CHANGES TO A SIGNIFICANT UPSLOPE EVENT BY WED WITH PERHAPS A TRAILING DEFORMATION BAND OF SNOW WORKING EAST TOWARD THE BLUE RIDGE WED MORNING. THIS MAY RESULT IN A FEW INCHES OF SNOW ACCUMULATION AROUND KBLF/KLWB AND POSSIBLY A LIGHT AMOUNT EAST TO KBCB. WIND WILL ALSO BECOME AN ISSUE ACROSS THE MOUNTAINS WITH NW WIND GUSTS TO 45 KTS OR MORE WED WITH A SIGNIFICANT COASTAL LOW MOVING ACROSS COASTAL NEW ENGLAND. RAPID IMPROVEMENT WILL OCCUR ON THURSDAY AS THE STORM SYSTEM PULLS AWAY AND DRIER AIR WORKS IN...RESULTING IN WIDESPREAD VFR CONDITIONS. VFR THEN CONTINUES UNDER HIGH PRESSURE FOR FRIDAY THROUGH SATURDAY. && .HYDROLOGY... AS OF NOON EST MONDAY... MODEL CONSENSUS AND HPC GUIDANCE GENERALLY IN THE 2 TO 3 INCH RANGE OF LIQUID QPF FOR THE IMPENDING STORM EVENT ALTHOUGH SOME SREF ENSEMBLE MEMBERS SHOWING OVER 4 INCHES BY ABOUT 12Z WEDNESDAY THE 27TH. QUESTION IS WHAT IMPACT THE RUNOFF FROM THIS WILL HAVE ON AREA STREAMS AND RIVERS. POINT ONE IS THAT RIVERS ARE STARTING OFF AT VERY LOW LEVELS ESPECIALLY ACROSS THE LOWER PORTIONS OF OUR RIVER BASINS...ACROSS THE PIEDMONT. USGS DAILY STREAMFLOW PERCENTILES AS OF THIS MORNING ARE SHOWING NEARLY ALL PIEDMONT RIVER AND STREAM LOCATIONS RUNNING AT FLOWS BELOW THE 25TH PERCENTILE FOR THE DATE AND SOME BELOW THE 10TH PERCENTILE. THIS ALSO HOLDS TRUE FOR MUCH OF THE UPPER JAMES RIVER BASIN. 60-DAY RAINFALL DEFICITS HAVE BECOME QUITE SIGNIFICANT...REACHING 4 TO 6 INCHES IN MANY OF THESE BASINS OR AROUND 25 PERCENT OF NORMAL. DETERMINISTIC RIVER FORECASTS ISSUED THIS MORNING BY THE FOUR RFCS SERVING THE BLACKSBURG HYDRO SERVICE AREA INCLUDE 48 HOURS OF QPF THROUGH 12Z WEDNESDAY OF GENERALLY 2 TO 2.5 INCHES. AT OF THIS PACKAGE NO RIVERS ARE FORECAST TO REACH FLOOD STAGE OR EVEN ACTION STAGE (GENERALLY A FEW FEET BELOW FLOOD STAGE) ALTHOUGH SEVERAL COME CLOSE...INCLUDING THE NORTH FORK HOLSTON RIVER AT SALTVILLE AND GREENBRIER RIVER AT ALDERSON. THAT SAID HYDROLOGIC MODELS TEND TO HAVE SOME DIFFICULTY AFTER EXTENDED DRY PERIODS IN HANDLING RUNOFF WHICH IS GENERALLY MUCH MORE EFFICIENT IN THE COOL SEASON. HENCE...THE RESPONSE ON RIVERS REMAINS SOMEWHAT UNCERTAIN BUT NOT ENOUGH CONFIDENCE TO ISSUE A FLOOD WATCH. NOT EXPECTING MUCH IF ANY CONVECTION WITH THIS STORM SO RAINFALL RATES SHOULD REMAIN MODEST..IN THE 0.10 TO 0.25 INCH PER HOUR RANGE. BUT HIGHER RAINFALL RATES IN ANY ELEVATED STORMS THAT ARE ABLE TO DEVELOP COULD LEAD TO LOCALIZED RUNOFF PROBLEMS. THESE COULD BE HANDLED WITH SHORT-FUSE HYDROLOGIC PRODUCTS..FLOOD ADVISORIES OR EVEN FLASH FLOOD WARNINGS BUT THE LIKELIHOOD AT THIS POINT IS QUITE LOW FOR THIS TO OCCUR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR VAZ018>020- 023-024-035. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ007- 009>017. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ022- 032>034-043>047-058-059. NC...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NCZ001-002- 018. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NCZ003>006- 019-020. WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ045. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR WVZ042>044. && $$ SYNOPSIS...RAB/WP NEAR TERM...JH/WP SHORT TERM...KK LONG TERM...SK AVIATION...JH/RAB/WP HYDROLOGY...PC
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
925 AM EST TUE NOV 26 2013 ...ISOLATED SEVERE WEATHER POSSIBLE THIS EVENING AND OVERNIGHT... .UPDATE (REST OF TODAY THROUGH WEDNESDAY MORNING)... 14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN AMPLIFIED AND HIGHLY ENERGETIC UPPER LEVEL PATTERN EVOLVING ACROSS THE CONUS. FLOW RIDGES SHARPLY OVER THE PACIFIC COAST AND INTER-MOUNTAIN WEST BEFORE DIVING BACK SOUTH INTO DEEP LONGWAVE TROUGHING COVERING THE REMAINDER OF THE NATION. THIS LONGWAVE TROUGH IS RATHER COMPLEX WITH BOTH A STRONG NORTHERN STREAM AND SOUTHERN STREAM IMPULSE EMBEDDED WITHIN. THE NORTHERN STREAM ENERGY IS DROPPING QUICKLY SOUTHEASTWARD OVER THE UPPER MIDWEST/GREAT LAKES WHILE THE SOUTHERN STREAM IMPULSE IS CURRENTLY EJECTING EASTWARD OVER THE WESTERN GULF OF MEXICO FROM THE SOUTHERN PLAINS. IT IS THIS POTENT SOUTHERN STREAM IMPULSE WHICH WILL BE THE BIG PLAYER IN OUR WEATHER OVER THE NEXT 24 HOURS AS IT SWINGS EASTWARD ALONG THE NORTHERN GULF COAST. CURRENTLY AT THE SURFACE...THE FLORIDA PENINSULA RESIDES WITH A ZONE OF MODERATE SOUTHEASTERLY FLOW TO THE SOUTH OF A EAST-WEST ORIENTED WARM FRONT ALIGNED NEAR THE I-10 CORRIDOR. THIS WARM FRONT TRAILS BACK TO AN AREA OF LOW PRESSURE NEAR AL COAST. FROM THIS LOW...A COLD FRONT TRAILS SOUTHWARD ACROSS THE CENTRAL GULF OF MEXICO AND WILL MOVE QUICKLY EASTWARD TO CROSS OUR FORECAST AREA TONIGHT. REGIONAL RADARS SHOWING WIDESPREAD SHOWERS/RAIN ASSOCIATED WITH THE UPGLIDE OVER THE WARM FRONT LIFTING QUICKLY NORTHWARD. MUCH OF THE FORECAST AREA IS NOW LEFT IN A ZONE OF WEAKER LIFT AS WE AWAIT THE SYNOPTIC FORCING ASSOCIATED WITH THE APPROACHING IMPULSE/TROUGH LATER TODAY AND TONIGHT. THEREFORE...FOR A MAJORITY OF THE DAY...THE SHOWER ACTIVITY WILL BE MORE SCATTERED "OFF AND ON" TYPE OF REGIME AS OPPOSED TO THE STEADIER PRECIP THAT THE CENTRAL AND NORTHERN ZONES SAW EARLIER IN THE MORNING. SKIES ARE MOSTLY CLOUDY TO CLOUDY REGION-WIDE AND ZONES FROM TAMPA NORTHWARD ARE LIKELY TO REMAIN MOSTLY CLOUDY THROUGH THE DAY. FARTHER SOUTH FROM THE WARM FRONT OVER OUR SOUTHERN ZONES...WILL NOT BE SURPRISED TO SEE AT LEAST SOME SUNNY BREAKS EVENTUALLY DEVELOP. ALTHOUGH...THE ADDED INSTABILITY FROM ANY INSOLATION WOULD LIKELY RESULT IN MORE SCATTERED SHOWERS. THE POTENTIALLY MORE SIGNIFICANT WEATHER WILL BEGIN TO APPROACH FROM THE EASTERN GULF OF MEXICO LATE THIS AFTERNOON/EARLY EVENING. AS WE HEAD THROUGH THE LATER AFTERNOON AND ESPECIALLY THE EVENING HOURS...LARGE SCALE FORCING FOR ASCENT ASSOCIATED WITH DCVA/HEIGHT FALLS WILL OVERSPREAD THE AREA. GFS/ECMWF BOTH SHOW A BROAD EXPANSE OF DEEP LAYER QG FORCING IN PLACE THIS EVENING. THIS IS ONE OF THE MORE POTENT MID/UPPER LEVEL IMPULSES THAT WE HAVE SEEN MOVE ACROSS THE NE GULF IN SOME TIME. UPPER LEVEL PV ANOMALY ASSOCIATED WITH THIS IMPULSE IS VERY IMPRESSIVE WITH THE DYNAMIC TROPOPAUSE FOLDED DOWN ALMOST TO 600MB RESULTING IN AN EQUALLY IMPRESSIVE MID/UPPER LEVEL JET STRUCTURE. SURFACE LOW REFLECTION AS A RESULT SHOULD CONTINUE TO DEEPEN THROUGH THE DAY/EVENING AHEAD OF THIS FEATURE AS IT CROSSES INTO SOUTHERN GA. THE COLD FRONT WILL ALSO INTENSIFY/SHARPEN WITH TIME ADDING A LOWER LEVEL CONVERGENCE FOCUS. ALL THAT BEING SAID...WOULD EXPECT MOST (IF NOT ALL) LOCATIONS TO SEE A SECONDARY ROUND OR 2 OF SHOWERS/STORMS BEGINNING LATE THIS AFTERNOON INTO THE EVENING AND THEN ENDING QUICKLY FROM WEST TO EAST DURING THE OVERNIGHT AS THE COLD FRONT SWEEPS ACROSS. RAIN CHANCES ARE CATEGORICAL 80% OR HIGHER FOR JUST ABOUT ALL ZONES THIS EVENING/OVERNIGHT...BUT TAPER QUICKLY AFTER 2AM...AND HAVE REMOVED ALL RAIN CHANCES (EVEN FOR OUR FAR EASTERN ZONES) BY SUNRISE TOMORROW MORNING. THE CONVECTIVE START AND END TIMES AGREE WELL WITH THE ENSEMBLE SUITE OF LOCAL/NATIONAL HIGH RESOLUTION MODELS AND ALSO THE HOPWRF ENSEMBLES BEING RUN OVER THE SE CONUS TODAY. SEVERE THREAT...DESPITE THE EXPECTED WIDESPREAD COVERAGE OF SHOWER AND STORMS DUE TO THE FORCING...THE OVERALL SEVERE THREAT SHOULD BE ISOLATED IN NATURE. THE STORM PREDICTION CENTER HAS OUTLOOKED MUCH OF OUR AREA IN A SLIGHT RISK FOR SEVERE WEATHER AND AGREE WITH THIS ASSESSMENT. DEEP LAYER 0-6KM BULK SHEAR (35-40KTS) AND MLCAPE (250-500 J/KG) IS NOT OVERLY IMPRESSIVE FOR OUR ZONES...BUT SUFFICIENT FOR ORGANIZED CONVECTION. MID-LEVEL LAPSE RATES ARE POOR FOR MUCH OF THE EVENT...HOWEVER THE LACK OF OVERALL BUOYANCY COULD BE OFFSET SOMEWHAT BY THE TENDENCY FOR THE UPDRAFTS TO ROTATE. LOW LEVEL JET WILL BE STRONGEST 40-50KTS OVER THE NATURE COAST ZONES...AND THEN WEAKEN WITH SOUTHWARD EXTENSION. ALL THIS BEING SAID...THE POTENTIAL CERTAINLY EXISTS FOR ISOLATED SEVERE WEATHER. THE MAIN THREAT WILL BE FOR DAMAGING STRAIGHT-LINE WINDS. AN ISOLATED TORNADO IS POSSIBLE AS WELL. THE BEST SETUP FOR AN ISOLATED TORNADO LOOKS TO EXIST OVER THE NATURE COAST ZONES WHERE THE MORE PRONOUNCED LOW LEVEL JET EXISTS RESULTING IN 0-1KM SHEAR OF AROUND 30KTS. UPPER SHORTWAVE TAKES ON AN INCREASINGLY NEGATIVE TILT AND ROTATES TO THE NORTHEAST OF THE AREA DURING WEDNESDAY MORNING. RAIN WILL BE OVER WITH THE COLD FRONT OFF TO OUR EAST BY SUNRISE. DEEP LAYER MOISTURE WILL ALSO QUICKLY EXIT ALLOWING FOR GENERALLY CLEARING SKIES. HOWEVER...CAA IN THE WAKE OF THE FRONT OVER THE GULF WILL LIKELY PRODUCE SOME COLD AIR STRATOCU THAT MAY MIGRATE ONSHORE FROM TIME TO TIME (ESPECIALLY FROM PINELLAS COUNTY SOUTHWARD). THOSE TRAVELING FOR THE THANKSGIVING HOLIDAY ON WEDNESDAY ALONG I-4 OR FLORIDA I-75 CORRIDORS SHOULD EXPERIENCE FAIR WEATHER WITH A GUSTY NW WIND. HIGH TEMPERATURES WILL BE COOLER WITH MAINLY 60S FROM TAMPA BAY NORTHWARD AND AROUND 70 FURTHER SOUTH. && .AVIATION... BKN CIGS...OCNL MVFR/IFR...WITH SHRA OR -RA THROUGH MID MORNING. AN ADVANCING FRONTAL SYSTEM WILL BRING VCTS BEGINNING AROUND 8-20Z WITH TSRA STARTING BETWEEN 00-04Z...WITH TEMPO MVFR/IFR EXPECTED. GUSTY WINDS SHIFT TO WEST AND NW AS THE FRONT MOVES ACROSS TONIGHT. && .MARINE... A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL COASTAL WATERS THROUGH WEDNESDAY EVENING...BUT THIS WILL LIKELY BE EXTENDED. SOME AREAS COULD SEE WINDS THAT DROP BELOW ADVISORY LEVELS FOR A BRIEF TIME...ESPECIALLY LATER THIS MORNING BETWEEN THE WARM AND COLD FRONTAL PASSAGES...BUT THEY WILL INCREASE RAPIDLY AGAIN WITH THE COLD FRONT OVERNIGHT INTO WEDNESDAY MORNING. BUFKIT SOUNDING PROFILES SHOWING IMPRESSIVE LOW LEVEL LAPSE RATES OVER THE WATER BEHIND THE FRONT WHICH WILL ALLOW FOR HIGHLY EFFICIENT MIXING OF DOWNWARD MOMENTUM AND LIKELY AT LEAST A PERIOD OF HIGH END ADVISORY WINDS WEDNESDAY MORNING. SEAS WILL REACH UP TO 10 FEET OR SO OFFSHORE BY EARLY WEDNESDAY MORNING. CONDITIONS WILL IMPROVE TOWARD THE END OF THE WEEK...BUT WE COULD STILL SEE WIND SPEEDS CLOSE TO CAUTIONARY OR ADVISORY LEVELS THROUGH SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... TPA 81 64 68 39 / 70 100 10 10 FMY 82 69 73 44 / 50 90 10 10 GIF 79 63 69 39 / 90 90 10 10 SRQ 82 67 70 43 / 60 90 10 10 BKV 79 62 65 32 / 90 100 10 10 SPG 80 65 67 47 / 70 100 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RIP CURRENT RISK FROM 1 PM EST THIS AFTERNOON THROUGH WEDNESDAY EVENING FOR CHARLOTTE-HILLSBOROUGH-LEE- MANATEE-PINELLAS-SARASOTA. HIGH SURF ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST WEDNESDAY FOR CHARLOTTE-HILLSBOROUGH-LEE-MANATEE- PINELLAS-SARASOTA. GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM- TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM. && $$ UPDATE/MARINE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
747 AM EST TUE NOV 26 2013 .SYNOPSIS... EAST COAST BOUND LOW PRESSURE WILL SPREAD A WINTRY MIX OF PRECIPITATION OVER THE REGION TODAY. THAT PRECIPITATION WILL CHANGE TO ALL SNOW TONIGHT. && .NEAR TERM /THROUGH WEDNESDAY/... CONFLUENT FLOW AS WELL AS A TIGHT BAND OF FRONTOGENESIS THAT WAS WELL SAMPLED ON THE NAM BETWEEN 500 AND 300 MB...WHICH IS ROUGHLY COINCIDENT WITH THE DENDRITIC GROWTH ZONE HAS RESULTED IN A BAND OF FAIRLY STEADY SNOWFALL THAT HAS PUSHED SLOWLY FROM SOUTH TO NORTH ALREADY THIS MORNING FROM ZANESVILLE TO WHEELING TO PITTSBURGH TO LATROBE. AMOUNTS TO THIS POINT OUT OF THIS BAND HAVE BEEN ROUGHLY 1.5 TO 3.5 INCHES...HOWEVER RECENT RADAR TRENDS AS WELL AS MODEL TRENDS SUGGEST THIS BAND IS LIKELY TO STRENGTHEN AS A WARMER PUSH OF AIR ALOFT IS SET TO ADVANCE NORTHWARD THROUGH THE MORNING HOURS AS IT SLOWLY MEANDERS NORTHWARD. QPF AND SNOW AMOUNTS WERE BUMPED UPWARD SUBSTANTIALLY IN THIS BAND THROUGH THE MORNING HOURS...WITH IMPRESSIVE 20:1 RATIOS NOTED AT THE NWS OFFICE THIS MORNING. WHILE THESE RATIOS ARE UNLIKELY TO LAST AFTER SUN UP...IT STILL SEEMS REASONABLE TO ANTICIPATE THAT AT LEAST 10:1 WOULD PERSIST BEYOND SUNRISE. THE REST OF THE FORECAST STILL LOOKS GOOD FOR TRANSITIONS TO RAIN/SLEET/FREEZING RAIN IN PORTIONS OF THE AREA. THE DETAILS OF THE RATIONALE OF THAT PORTION OF THE FORECAST ARE CONTAINED BELOW. FRIES PREVIOUS... A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE. NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL. THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE DOMINANT PRECIPITATION TYPE. BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING. TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES. ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE EFFECT MACHINE TO START UP. ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE NEEDED TO ANY OF THE ADVISORIES OR WARNINGS. && .SHORT TERM /WEDNESDAY NIGHT/... UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL BRING LOWS DOWN INTO THE UPPER TEENS. && .LONG TERM /THURSDAY THROUGH MONDAY/... DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... DETERIORATION TO GENL IFR WL CONT TDA AS LGT SN...THEN A MIXTURE OF WINTRY PCPN SPREADS OVR THE REGION WITH LOW PRES EMERGING FM THE GULF COAST AREA. IFR CONDITIONS WL THEN PREVAIL THROUGH TNGT WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW. .OUTLOOK.../WEDNESDAY THROUGH SATURDAY/... WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR MDZ001. OH...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR OHZ039>041- 048>050-057-058. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR OHZ059- 068-069. PA...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR PAZ013>016- 020>022. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR PAZ023- 029. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR PAZ031- 073-075. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR PAZ074-076. WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR PAZ007>009. WV...WINTER STORM WARNING UNTIL 1 PM EST WEDNESDAY FOR WVZ001-002. WINTER WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR WVZ003- 004. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR WVZ012-021-022. WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
625 AM EST TUE NOV 26 2013 .SYNOPSIS... EAST COAST BOUND LOW PRESSURE WILL SPREAD A WINTRY MIX OF PRECIPITATION OVER THE REGION TODAY. THAT PRECIPITATION WILL CHANGE TO ALL SNOW TONIGHT. && .NEAR TERM /THROUGH WEDNESDAY/... ONLY CHANGES FOR THE NR DAWN UPDATE WERE TWEAKS TO HOURLY TRENDS OF TEMP...PCPN TYPE...AND NR TERM SNOW AMOUNTS OVR AREAS EAST OF PIT. PREVIOUS... A SHORTWAVE MOVING ACROSS OHIO INTO NORTHWESTERN PENNSYLVANIA HAS ALLOWED FOR A PRECURSOR ROUND OF SNOW IN ADVANCE OF THE MAJOR SYSTEM ARRIVING THIS MORNING. AN INCH OF SNOW HAS FALLEN AT OUR OFFICE...AND AREA WEBCAMS SHOW SOME LIGHT ACCUMULATIONS GENERALLY ON GRASSY SURFACES...ALTHOUGH AREA ROADWAYS STILL APPEAR TO BE MOSTLY WET. THIS LIGHT SNOW SHOULD CONTINUE THROUGH SUNRISE. NORTHERN STREAM AND SOUTHERN STREAM SYSTEMS ARE BOTH STARTING THEIR TREK TO THE EAST...WITH THEIR INTERACTION ABOUT TO AFFECT THE ENTIRE EAST COAST. SO FAR THE PRECIPITATION SHIELD FROM THE SOUTHERN SYSTEM IS CONTAINED TO SOUTHERN KENTUCKY AND VIRGINIA...WITH PRECIPITATION MOVING TO THE NORTHEAST. TRICKIEST PORTION OF THE FORECAST REMAINS WHAT WILL HAPPEN WITH LOW LEVEL TEMPERATURE PROFILES. ENOUGH WARM AIR IS EXPECTED TO MOVE IN ALOFT THAT A MIX OF SNOW AND FREEZING RAIN IS POSSIBLE GENERALLY SOUTH AND EAST OF A LINE FROM ZANESVILLE TO PITTSBURGH TO DUBOIS DURING THE DAYTIME. IN ADDITION...SURFACE TEMPERATURES WILL BE CRITICAL...AS PRECIP MAY ACTUALLY FALL AS RAIN FOR A SEVERAL HOUR PERIOD. LATEST RUNS OF THE RAP STILL SHOW ABOVE FREEZING TEMPERATURES REACHING ALL THE WAY INTO INDIANA COUNTY NEAR THE SURFACE. THE RAP CAME IN AS THE WARMEST MODEL FOR SURFACE TEMPERATURES...BUT IT ALSO USUALLY HANDLES THESE SITUATIONS WELL. THE HIGHER ELEVATIONS IN THE RIDGES WILL LIKELY HAVE A WINTRY MIX THROUGH MUCH OF THIS TIME PERIOD WITH AN EXTENDED PERIOD OF FREEZING RAIN POSSIBLE. NORTH AND WEST OF THE ZZV/PIT/DUJ LINE...SOME SLEET MAY MIX IN BY THE AFTERNOON...BUT SNOW IS EXPECTED TO BE THE DOMINANT PRECIPITATION TYPE. BY EVENING THE TWO SYSTEMS ARE EXPECTED TO BE IN ENOUGH PROXIMITY TO EACH OTHER TO DEVELOP A COUPLED JET...AND CONSEQUENTLY SHOULD BE THE TIME PERIOD WHEN THE HIGHEST PRECIPITATION RATES OCCUR. IN THE RIDGES...FREEZING RAIN WILL CONTINUE THROUGH THE EVENING. TEMPERATURES WILL LIKELY STILL BE WARM ENOUGH SOUTH AND EAST OF PITTSBURGH OUTSIDE OF THE HIGHEST ELEVATIONS TO PERSIST WITH RAIN FOR A FEW HOURS. HOWEVER...WITH ALL SNOW FALLING TO THE WEST OF PITTSBURGH...SNOW RATES COULD BE QUITE IMPRESSIVE DURING THE EVENING HOURS FROM ZANESVILLE TO NEW CASTLE AND FRANKLIN. AFTER MIDNIGHT NEARLY ALL LOCATIONS WILL CHANGEOVER TO SNOW...WITH RATES BEGINNING TO DIMINISH SLIGHTLY. IF THE WARM LAYER ALOFT PERSISTS...WHICH LATEST MODELS RUNS HAVE BEEN INDICATING IS POSSIBLE...FREEZING RAIN MAY HOLD ON FOR A FEW MORE HOURS IN THE RIDGES. ALTHOUGH ALL LOCATIONS WILL CONTINUE TO RECEIVE SNOW WEDNESDAY MORNING...THE WIDESPREAD PRECIPITATION SHIELD WILL BE MOVING OFF TO THE EAST. ALTHOUGH WINDS WILL INITIALLY BE OUT OF THE NORTH-NORTHWEST...LESS FAVORABLE FOR UPSLOPE/LAKE EFFECT...WINDS WILL BACK TO THE NORTHWEST BY THE AFTERNOON AND ALLOW THE LAKE EFFECT MACHINE TO START UP. ALL IN ALL...ONLY MINOR CHANGES WERE MADE TO THE FORECAST THROUGH THIS TIME PERIOD. THE AXIS OF HEAVIEST SNOWFALL WAS PUSHED SLIGHTLY FARTHER TO THE WEST TO ALIGN WITH DEFORMATION ZONE AND THE CHANCES FOR FREEZING RAIN WERE HELD ONTO LONGER TONIGHT IN THE RIDGES...BUT OTHERWISE THE INHERITED FORECAST WAS IN GOOD SHAPE. NO CHANGES WERE NEEDED TO ANY OF THE ADVISORIES OR WARNINGS. && .SHORT TERM /WEDNESDAY NIGHT/... UPSLOPE AND LAKE EFFECT SNOW WILL CONTINUE WEDNESDAY NIGHT. MODELS ARE SUGGESTING THAT A DOUBLE LAKE CONNECTION BETWEEN HURON-ERIE IS POSSIBLE...WHICH COULD RESULT IN SOME LOCALLY HIGHER TOTALS IF A SINGLE DOMINANT BAND DEVELOP SIMILAR TO WHAT HAPPENED THIS PREVIOUS SATURDAY. THE RETURN OF WEST-NORTHWESTERLY FLOW WILL BRING LOWS DOWN INTO THE UPPER TEENS. && .LONG TERM /THURSDAY THROUGH MONDAY/... DRYING TREND CAN BE ANTICIPATED INTO THE WEEKEND AS THE UPR FLOW FLATTENS...ALTHOUGH SUB AVG TEMPS WL CONT UNTIL WARM ADVCTN INTENSIFIES WITH THE ADVN OF LOW PRES EARLY NXT WEEK. PASSAGE OF THAT TROF IS GFS AND ECMWF FORECAST TO SPREAD RAIN...OR SNOW OVR THE UPPER OH VALLEY REGION ON MONDAY AND TUESDAY. CHC POPS WERE THUS INCLUDED FOR THAT TIME FRAME...BUT RESOLUTION OF PCPN TYPE WL HAVE TO WAIT UNTIL THE SITUATION FURTHER MATURES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... DETERIORATION TO GENL IFR WL CONT TDA AS LGT SN...THEN A MIXTURE OF WINTRY PCPN SPREADS OVR THE REGION WITH LOW PRES EMERGING FM THE GULF COAST AREA. IFR CONDITIONS WL THEN PREVAIL THROUGH TNGT WITH COLD ADVCNT CHANGING PCPN TO ALL SNOW. .OUTLOOK.../WEDNESDAY THROUGH SATURDAY/... WDSPRD RSTRNS WL CONT THRU WED NGT AS COLD ADVCTN INTENSIFIES IN THE WAKE OF EXITING LOW PRES. VFR IS EXPD TO RTN LTR THU WITH BLDG HIGH PRES AND PERSIST FOR THE RMNDR OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR MDZ001. OH...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR OHZ039>041-048>050-057-058. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR OHZ059-068-069. PA...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR PAZ013>016-020>022. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR PAZ023-029. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR PAZ031-073-075. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR PAZ074-076. WINTER STORM WARNING FROM NOON TODAY TO 4 AM EST THURSDAY FOR PAZ007>009. WV...WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR WVZ001-002. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 1 PM EST WEDNESDAY FOR WVZ003-004. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR WVZ012-021-022. WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ023-041. && $$ 15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
701 AM EST TUE NOV 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW. HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT. TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO -17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING. TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 6 INCH RANGE. WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE. SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON TRACK. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 443 AM EST TUE NOV 26 2013 LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN FORECAST FOCUS. IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER ACROSS THE CONUS. BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO -20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY. EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8 MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S ACROSS THE AREA. WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9 WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9 WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN. MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO ACCOUNT FOR THE SHORTWAVE. SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN. ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW. NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING TROUGH OVR SCNTRL CANADA. SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG TERM TIME RANGE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM EST TUE NOV 26 2013 THE PASSAGE OF A LOW PRES TROUGH WILL BRING INCREASING LES INTENSITY AT IWD/CMX THIS MORNING WITH OCNL IFR CONDITIONS LIKELY. AFTER ANOTHER LOW PRES TROUGH TRACKS THROUGH THE AREA IN THE EVENING...A WIND SHIFT TO A MORE N DIRECTION WILL NOT FAVOR CMX...SO MVFR CONDITIONS ARE EXPECTED THERE. ON THE OTHER HAND...THE WIND SHIFT WILL FAVOR IWD...SO IFR CONDITIONS SHOULD PREVAIL THERE LATE IN THE FCST PERIOD. EXPECT VFR WX AT SAW TO PREDOMINATE INTO THIS EVENING WITH A DOWNSLOPE WIND COMPONENT. BUT CONDITIONS THERE ARE LIKELY TO DETERIORATE QUICKLY LATE IN THE PERIOD WITH THE WIND SHIFT TO A FAVORABLE UPSLOPE N DIRECTION FOLLOWING THE LOW PRES TROUGH PASSAGE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST TUE NOV 26 2013 NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT RELAXES AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM EST WEDNESDAY FOR MIZ006. LAKE SUPERIOR... GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
519 AM EST TUE NOV 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW. HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT. TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO -17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING. TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 6 INCH RANGE. WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE. SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON TRACK. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 443 AM EST TUE NOV 26 2013 LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN FORECAST FOCUS. IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER ACROSS THE CONUS. BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO -20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY. EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8 MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S ACROSS THE AREA. WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9 WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9 WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN. MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO ACCOUNT FOR THE SHORTWAVE. SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN. ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW. NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING TROUGH OVR SCNTRL CANADA. SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG TERM TIME RANGE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1242 AM EST TUE NOV 26 2013 A WEAK HI PRES RDG/FAIRLY DRY LLVL AIR SHOWN ON THE 00Z INL RAOB WL BRING A LULL IN THE LES EARLY THIS MRNG...WITH NO WORSE THAN MVFR CONDITIONS PREDOMINATING EVEN WITH AN UPSLOPE WNW FLOW AT IWD AND CMX. BUT THE PASSAGE OF A LO PRES TROF ARND SUNRISE WL LIKELY REINTENSIFY THE SHSN AT THESE LOCATIONS AND CAUSE SOME IFR VSBYS. ALTHOUGH ANOTHER LO PRES TROF WL TRACK THRU THE AREA IN THE EVNG... A WSHFT TO A MORE N DIRECTION WL NOT FAVOR CMX...SO FCST MVFR CONDITIONS HERE. ON THE OTHER HAND...THIS WSHFT WL FAVOR IWD...SO IFR CONDITIONS SHOULD PREVAIL THERE LATE IN THE FCST PERIOD. EXPECT VFR WX AT SAW TO PREDOMINATE INTO THIS EVNG WITH A DOWNSLOPE WIND COMPONENT. BUT CONDITIONS THERE ARE LIKELY TO DETERIORATE QUICKLY LATE IN THE PERIOD WITH THE WSHFT TO A FVRBL UPSLOPE N DIRECTION FOLLOWING THE LO PRES TROF PASSAGE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST TUE NOV 26 2013 NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT RELAXES AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM EST WEDNESDAY FOR MIZ006. LAKE SUPERIOR... GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...JLA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
648 AM EST TUE NOV 26 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE NORTHERN GULF OF MEXICO WILL RAPIDLY INTENSIFY AS IT LIFTS NORTHEASTWARD THROUGH THE CAROLINAS AND MIDDLE ATLANTIC STATES TODAY AND TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD EAST OF THE APPALACHIANS WEDNESDAY AND WEDNESDAY NIGHT...THEN LINGER THROUGH THE END OF THE WEEK. && UPDATED TO ADD GRANVILLE...VANCE...AND STANLY COUNTIES TO THE WINTER WEATHER ADVISORY. .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM TUESDAY... PRECIPITATION HAS BEEN A LITTLE SLOWER THAN EXPECTED TO SPREAD IN TO CENTRAL NC THIS MORNING...WITH ONLY KINT HAVING REPORTED A LITTLE MIX OF SLEET AND RAIN THUS FAR. ISENTROPIC UPGLIDE DRIVEN BY A STRENGTHENING AND EASTWARD-EXPANDING H85 LLJ OF 35-40 KTS WILL NONETHELESS SUPPORT FURTHER LIFT AND MOISTENING TO ALLOW INCREASING RADAR RETURNS PER KGSP RADAR TO OVERSPREAD THE NORTHWEST PIEDMONT BETWEEN 5 AND 8 AM...PER RECENT RUNS OF THE HRRR AND RAP. THE SPECIAL RELEASE 06Z KGSO RAOB INDICATED THIS MOISTENING PROCESS WAS WELL UNDERWAY...WITH JUST A COUPLE OF SHALLOW...BUT STOUT DRY LAYERS AROUND 10 THOUSAND...AND THE LOWEST 3 THOUSAND...FT REMAINING. THE FORECAST WET BULB FREEZING LINE IS STILL FORECAST TO RETREAT ACROSS THE PIEDMONT THROUGH 10-11 AM...A LITTLE MORE SLOWLY THAN EARLIER PROGGED...AND STILL PROBABLY LINGERING OVER FORSYTH AND PERSON COUNTIES UNTIL AROUND NOON OR SO. IT WILL TAKE SOME TIME FOR THE PRECIPITATION TO EDGE INTO THE TRIANGLE - BETWEEN 8-11 AM - AND THE COASTAL PLAIN DURING THE MIDDAY HOURS. THERE WILL CONSEQUENTLY BE LITTLE OPPORTUNITY FOR ANYTHING BUT A CHILLY RAIN IN THOSE AREAS... WITH THE EXCEPTION OF THE FAR NORTHERN REACHES OF NORTHERN DURHAM COUNTY FOR AN HOUR OR TWO. THE PRECIPITATION AMOUNTS DURING THAT TIME WILL BE SO LIGHT THAT ANY VERY LIGHT FREEZING RAIN WOULD HAVE LITTLE TO NO IMPACT. THE BETTER CHANCE OF SEEING SEVERAL HUNDREDTHS...TO AROUND A TENTH OF AN INCH OVER THE FAR NW PIEDMONT...WILL OCCUR IN THE CURRENT ADVISORY AREA. THE OTHER NOTABLE TREND IN GUIDANCE HAS BEEN FOR A MORE INLAND TRACK OF THE SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO... AND ANOTHER PRECEDING LOW FORECAST TO DEVELOP OVER NC AND VA THIS EVENING...AS THE FORCING FOR ASCENT ATTENDANT THE NORTHERN STREAM OVERSPREADS THE LOW LEVEL FRONTAL ZONE. WHILE IT IS STILL LIKELY THE MODELS ARE TOO AGGRESSIVE ERADICATING THE WEDGE AND BARRELING THE WARM SECTOR ALL THE WAY INTO THE TRIAD THIS EVENING...IT IS HARD TO IGNORE THIS MORE INLAND TREND EVEN IN THE HI-RES NMM AND ARW CORES THAT TEND TO BETTER RESOLVE AND RESPECT CAD. EVEN THEY DRIVE THE FRONTAL ZONE TO NEAR OR JUST EAST OF HWY 1...AND THIS SOLUTION SEEMS ACCEPTABLE. BIG TEMPERATURE BUSTS REMAIN LIKELY INVOF THE FRONT...WHICH WILL LIKELY BE CHARACTERIZED BY A 25-30 DEGREE TEMPERATURE GRADIENT ACROSS SINGLE COUNTIES...WITH 30S IN THE RESIDUAL IN-SITU WEDGE OVER THE WESTERN PIEDMONT...AND 60S IN THE WARM SECTOR. TEMPERATURES WILL CHANGE LITTLE OVERNIGHT...WITH SOME GRADUAL RISES INTO THE 60S IN THE WARM SECTOR THE MOST LIKELY CHANGE FROM AFTERNOON TEMPS. THE MORE INLAND WARM SECTOR PENETRATION ALSO RAISES CONCERN FOR THE POTENTIAL FOR STRONG TO SEVERE CONVECTION...GIVEN THE EXTREME LOW AND DEEP SHEAR PROFILES ATTENDING THE RAPIDLY DEEPENING LOW PRESSURE SYSTEM AND INCREASINGLY-PHASED AND NEGATIVELY-TILTED TROUGH AXES ALOFT. THIS THREAT WOULD BE HIGHEST OVER THE COASTAL PLAIN AND FAR EASTERN SANDHILLS AND PIEDMONT AS THE NOSE OF THE LLJ ACCELERATES ACROSS EAST-CENTRAL NC AND SUPPORTS SCATTERED SURFACE-BASED...OR NEARLY SO...CONVECTION BETWEEN 7 PM AND 2 AM. FORECAST BUFR SOUNDINGS SUGGEST CONVECTION OF THE ELEVATED VARIETY COULD OCCUR IN THE CAD REGIME AS WELL...WITH UP TO A FEW HUNDRED J/KG OF MUCAPE INDICATED ACROSS ALL OF CENTRAL NC FOR SEVERAL HOURS THIS EVENING-EARLY TONIGHT. A MID LEVEL DRY SLOT MAY LARGELY END PRECIPITATION FOR A TIME OVERNIGHT...AFTER THE RAIN BECOMES HEAVY AT TIMES DURING THE AFTERNOON AND EVENING HOURS. THE BULK OF THE PREVIOUSLY FORECAST ONE TO TWO INCHES OF SOAKING RAIN (WELL BELOW FLASH FLOOD GUIDANCE)... HIGHEST WEST...WILL HAVE FALLEN BY THAT TIME. THE LEADING EDGE OF CONCENTRATED DCVA ATTENDING THE POTENT SOUTHERN STREAM SHORTWAVE TROUGH OVER WEST TX SHOULD THEN RESULT IN THE REDEVELOPMENT OF RAIN...PERHAPS IN THE FORM OF A BAND OF SHALLOW ELEVATED CONVECTION...LATE TONIGHT INTO EARLY WEDNESDAY. AREAS OF FOG... INCLUDING SOME DENSE OVER THE WESTERN PIEDMONT...WILL ALSO BE PROBABLE ON THE COOL SIDE OF THE BOUNDARY TONIGHT. && .SHORT TERM /WEDNESDAY/... AS OF 345 AM TUESDAY... GUIDANCE REMAINS CONSISTENT THAT THE DEPTH OF THE SATURATED LAYER WILL STRUGGLE TO REACH THE MINUS 10 LEVEL...AS THE STRONGEST HEIGHT FALLS/DYNAMICS ALOFT PIVOT NORTHEASTWARD. THE EXCEPTION WILL BE OVER THE WESTERN AND NORTHERN PIEDMONT...WHERE BRIEF DEEPENING TO NEAR MINUS 12...IN BAND OF LAST GASP DEFORMATION PRECIPITATION...IS FORECAST TO OCCUR IN THE SEVERAL HOURS CENTERED AROUND 18Z. A FEW WET FLAKES MAY CONSEQUENTLY MIX WITH THE RAIN AS THE PRECIPITATION COMES TO AND END DURING THE AFTERNOON. AREAS OUTSIDE OF THE DEFORMATION BAND...NAMELY OVER THE COASTAL COLAN AND PERHAPS SANDHILLS...WILL LIKELY RECEIVE LITTLE TO NO ADDITIONAL RAIN...WITH JUST A PARTLY CLOUDY SKY IN THE DRY SLOT. ALL AREAS WILL EXPERIENCE STRONG CAA...HOWEVER...WITH TEMPERATURES TUMBLING INTO THE 40S... AND 30S OVER THE WESTERN PIEDMONT...DURING THE LATE MORNING TO EARLY AFTERNOON HOURS. BLUSTERY NW WINDS WILL ALSO GUST TO BETWEEN 30 AND 35 MPH AS THE FRESH ARCTIC AIR MASS SURGES ACROSS THE STATE BEHIND THE RAPIDLY DEEPENING LOW BOUND FOR NEW ENGLAND AND EASTERN CANADA...WHICH WILL YIELD WIND CHILL VALUES ABOUT 15 DEGREES COOLER THAN THE AFOREMENTIONED AIR TEMPS IN THE 30S-40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... AS OF 250 AM TUESDAY... WEDNESDAY NIGHT THROUGH SUNDAY: AS THE COLD FRONT MOVES FARTHER OFF THE CAROLINA COAST AND THE LOW MOVES NE AWAY FROM THE AREA...SKIES WILL BEGIN TO CLEAR AND LOW TEMPS FOR WEDNESDAY NIGHT WILL DROP INTO THE LOW 20S NW TO UPPER 20S EAST. WINDS WILL REMAIN BREEZY OVERNIGHT UNTIL THE PRESSURE GRADIENT RELAXES AND SURFACE HIGH PRESSURE MOVES OVER THE APPALACHIANS ON THURSDAY. WITH THE COLD HIGH PRESSURE IN PLACE...EXPECT HIGHS ON THURSDAY IN THE UPPER 30S TO LOW 40 AND OVERNIGHT LOWS SIMILAR TO THE PREVIOUS NIGHT...LOW TO UPPER 20S. THE SURFACE HIGH SHOULD MIGRATE OVER THE GREAT LAKES AND INTO THE NORTHEAST BY FRIDAY WITH THE RIDGE EXTENDING SOUTHWEST INTO CENTRAL NC WHERE IT WILL REMAIN THROUGH SUNDAY. THE RESULT WILL BE A DRY FORECAST...MAINLY CLEAR SKIES AND COLD TEMPERATURES...WITH HIGHS FRIDAY IN THE MID TO UPPER 40S. HIGHS SATURDAY AND SUNDAY WILL BE DEPENDENT ON THE EASTWARD EXTENT OF THE WEDGE...BUT FOR NOW EXPECT GRADUALLY INCREASING HIGHS IN THE EAST INTO THE MID 50S BY SUNDAY... AND A SLOWER INCREASE IN THE NW...UPPER 40S SUNDAY. EXPECT A SIMILAR TREND IN OVERNIGHT LOWS...MID 20S TO NEAR 30 DEGREES FRIDAY NIGHT INCREASING SLIGHTLY INTO THE MID 20S TO LOW 30S FOR SATURDAY NIGHT. SUNDAY NIGHT THROUGH MONDAY NIGHT: THERE ARE DIFFERENCES BETWEEN THE MODELS WITH RESPECT TO UPPER LEVEL TROUGH AND PRECIP DEVELOPMENT FOR THIS PART OF THE FORECAST...BUT THEY INDICATE THE RIDGE WEAKENING AND CLOUD COVER INCREASING SUNDAY NIGHT AND MONDAY. EXPECT THE COLUMN TO MOISTEN AND CHANCES FOR PRECIP TO INCREASE...HOWEVER NAILING DOWN ANY TIMING IS DIFFICULT AT THIS TIME. FOR NOW WILL GRADUALLY INCREASE PRECIP CHANCES SUNDAY NIGHT THROUGH MONDAY NIGHT. SHOULD SEE HIGH TEMPS MODERATE A BIT...MID 50S TO LOW 60S FOR MONDAY. OVERNIGHT LOWS GENERALLY IN THE MID 30S TO LOW 40S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 645 AM TUESDAY... 24 HOUR TAF PERIOD: FREEZING RAIN HAS BEEN REPORTED THIS HOUR AT KGSO WITH UNKNOWN PRECIPITATION OCCURRING AT KINT. TEMPERATURES IN BOTH LOCATIONS ARE AT 32 DEGREES AND EXPECTED TO REMAIN THERE FOR THE NEXT COUPLE OF HOURS. RADAR SHOWS STEADY LIGHT RAIN OVER THE TRIAD BUT PERHAPS A BREAK IN THE RAIN COMING UP IN THE NEXT HOUR. AFTER 14Z EXPECT TEMPERATURES TO RISE BACK ABOVE FREEZING AND MODERATE RAIN WILL BE THE MAIN FORM OF PRECIPITATION FOR THE REST OF THE DAY. TO THE EAST NO THREAT OF FREEZING RAIN BUT MODERATE RAIN EXPECTED LATER TODAY. A GRAB BAG OF AVIATION CONDITIONS OUT THERE THIS MORNING WITH SOME IFR CEILINGS IN THE SOUTH...MAINLY MVFR IN THE NORTHWEST AND VFR HANGING ON IN THE EAST BUT NOT FOR LONG AS THEY WILL DIP TO MVFR AFTER THE ONSET OF PRECIPITATION LATER THIS MORNING. WINDS TO DAY WILL BE MAINLY NORTHEASTERLY NEAR 10 KNOTS WITH FASTER WIND SPEEDS IN THE SOUTHEAST. LATER TODAY AS THE LOW APPROACHES WINDS IN THE NORTHWEST WILL BE NORTHWESTERLY AND WINDS IN THE EAST WILL BE MORE SOUTHEASTERLY. OFF THE DECK...LOW LEVEL WIND SHEAR WILL BE A CONCERN NEAR THE 2000 FT LEVEL WITH 35-40 KNOT SOUTHEASTERLY SHEAR. THE GREATEST CONCERN FOR LLWS WILL BE IN THE TRIAD CONTINUING THROUGH TODAY TO THE EARLY MORNING HOURS WEDNESDAY. LIKELIHOOD OF LLWS DECREASES FOR EASTERN TERMINAL BUT WILL STILL BE PRESENT AT LEAST THROUGH TUESDAY AFTERNOON/EARLY EVENING. LONG TERM: RAIN WITH THIS SYSTEM WILL CONTINUE INTO WEDNESDAY AND WIND SPEEDS ARE EXPECTED TO INCREASE WEDNESDAY AFTERNOON WITH GUSTS UP TO 30 MPH POSSIBLE. THURSDAY THROUGH THE END OF THE WEEK SHOULD SEE A RETURN TO VFR CONDITIONS UNTIL THE NEXT STORM SYSTEM APPROACHES EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ007- 021>024-038-039. WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR NCZ008-009-073. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...KC AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
454 PM EST TUE NOV 26 2013 .SYNOPSIS... LOW PRESSURE OVER THE SOUTHEAST STATES LATE THIS AFTERNOON WILL INTENSIFY AND MOVE UP THE COAST TONIGHT...PASSING OVER THE AREA ON WEDNESDAY AND THEN HEADING INTO EASTERN CANADA WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BUILDS IN FROM THURSDAY THROUGH SATURDAY...AND MOVE OFF THE NEW ENGLAND COAST ON SUNDAY. A COASTAL FRONT WILL DEVELOP ON SUNDAY AND REMAIN INTO MONDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT AND MOVE ALONG THE COAST ON TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... IMPENDING STORM WILL BRING A VARIETY OF WEATHER HAZARDS BEGINNING TONIGHT. FIRST...SFC TEMPS HAVE BARELY BUDGED THIS AFTERNOON IN MOST OF ORANGE COUNTY WHILE TEMPS CONTINUE TO WARM ALOFT...WITH PRECIP CHANGING TO LIGHT FREEZING RAIN. HAVE THEREFORE CONTINUED THE WINTER WX ADVISORY THERE INTO THIS EVENING. TEMPS SHOULD EVENTUALLY RISE LATER THIS EVENING AS LOW LEVEL WARM ADVECTION CONTINUES...CHANGING PRECIP THERE TO ALL RAIN BY LATE EVENING. ELSEWHERE...RAIN WILL CONTINUE TONIGHT AND PICK UP IN INTENSITY FROM LATE EVENING ON AS PRIMARY LOW PRESSURE WEAKENS ALONG A LOW LEVEL BAROCLINIC ZONE ALONG THE COASTAL PLAIN...AND GIVES WAY TO A SECONDARY LOW OVER THE MID ATLANTIC FORMING UNDER THE STRENGTHENING RIGHT ENTRANCE REGION OF A DIFLUENT UPPER JET STREAK APPROACHING FROM THE WEST AS A NORTHERN/SOUTHERN STREAMS PHASE ALOFT. A S-SE LOW LEVEL JET WILL INTENSIFY EAST OF THE LOW OVERNIGHT... TRANSPORTING ATLANTIC/GULF MOISTURE INTO THE REGION AND PROVIDING AMPLE LOW LEVEL CONVERGENCE/LIFT FOR HEAVY RAIN. OROGRAPHIC LIFT WILL ALSO COME INTO PLAY NORTH/WEST OF NYC GIVEN THE LOW LEVEL SE FLOW TO START. GIVEN THESE FACTORS THE POTENTIAL FOR AREAL/URBAN FLOODING AND FLOODING OF SMALL STREAMS NOW LOOKS GREAT ENOUGH TO WARRANT A FLOOD WATCH. THE LLJ ALSO LOOKS STRONG ENOUGH TO SUPPORT STRONG SE-S WINDS ALONG THE COAST...SO THE WIND ADVY CONTINUES. VERY STRONG NAM LLJ WITH 85-95 KT AT H8 MAY LOOK LIKE AN OUTLIER COMPARED TO WEAKER/FARTHER EAST GFS/ECMWF...BUT LATEST RUNS OF THE RAP DO LEND IT SUPPORT SO AM NOT WILLING TO DISCOUNT IT. SFC-H8 INVERSION SHOULD PREVENT THE STRONGEST OF THESE WINDS FROM MIXING DOWN. HOWEVER HAVE A NAGGING CONCERN THAT DUCTED GRAVITY WAVES COULD AID IN DOWNWARD MOMENTUM TRANSPORT TOWARD MORNING PER AKQ RESEARCH...AS WEAK INSTABILITY MOVES IN ALOFT JUST NORTH OF AN APPROACHING WARM FRONT...AND AS THE UPPER JET STREAK APPROACHES THE DOWNSTREAM INFLECTION POINT BETWEEN THE UPPER TROUGH TO THE WEST AND OFFSHORE RIDGING...SO POTENTIAL FOR 60+ MPH WIND GUSTS ACROSS LONG ISLAND AND COASTAL SE CT WILL HAVE TO BE WATCHED. MOST LIKELY SCENARIO WILL BE FOR SUSTAINED WINDS 25-35 MPH WITH GUSTS 45-50 MPH...MAINLY IN/NEAR NYC AND ALONG THE COAST BEGINNING LATE TONIGHT. THERE COULD BE A FEW RUMBLES OF THUNDER LATE AS ELEVATED INSTABILITY MOVES OVER THE AREA. TEMPS WILL BE ON THE RISE TONIGHT...REACHING THE MID AND UPPER 50S BY MORNING. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... THE LOW WILL BE MOVING ACROSS THE REGION WED MORNING INTO EARLY AFTERNOON...THEN RE-CONSOLIDATING TO THE NORTH IN THE AFTERNOON. HEAVY RAIN...STRONG SOUTHERLY WINDS AND ISOLD RUMBLES OF THUNDER WILL STILL BE ONGOING INITIALLY...THEN SHOULD SHIFT TO THE EAST ACROSS ERN LONG ISLAND/CT DURING LATE MORNING AND LIFT UP INTO NEW ENGLAND BY AFTERNOON AS THIS TAKES PLACE. ENDED WIND ADVY EARLIER THAN ORIGINALLY FCST SINCE THE LOW TRACK SHOULD BE SLIGHTLY FARTHER EAST...WITH THE LLJ ALSO PASSING TO THE EAST SOONER. RAIN SHOULD LESSEN IN INTENSITY AS WELL AS AS THE LLJ PASSES TO THE EAST. AS THE LOW MOVES OVER THE AREA...THERE SHOULD BE A RELATIVE LULL IN WINDS FROM LATE MORNING INTO EARLY AFTERNOON...THEN STRONG NW WINDS WILL REDEVELOP BY EVENING AS THE LOW CONTINUES TO INTENSIFY AND SHOULD CONTINUE INTO THE NIGHT...SUSTAINED AT 20-30 MPH WITH GUSTS UP TO 40 MPH...POSSIBLY STRONGER IN NYC METRO AND LONG ISLAND WHERE ANOTHER WIND ADVY MAY BE NEEDED. STILL EXPECT SCT SHOWERS IN THE EVENING AS THE UPPER TROUGH MOVES ACROSS...AND LOW LEVEL CAA SHOULD CHANGE ANY PRECIP OVER TO SNOW FROM NYC NORTH/WEST. SOME INTERIOR AREAS COULD SEE A LIGHT COATING OF ACCUMULATION OF SNOW BEFORE ALL PRECIP ENDS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... VIGOROUS SHORTWAVE IS ROTATING EAST OF THE REGION EARLY THURSDAY MORNING AS BROAD UPPER TROUGH REMAINS ACROSS THE NORTHEAST. ANOTHER SHORTWAVE ROTATES THROUGH THE TROUGH LATE THURSDAY INTO THURSDAY NIGHT. MEANWHILE AT THE SURFACE LOW PRESSURE WILL BE NORTH AND EAST OF THE AREA AND CONTINUING TO MOVE NORTH DURING THE DAY INTO THURSDAY NIGHT AS HIGH PRESSURE BUILDS TO THE WEST. INCREASING SUBSIDENCE BEHIND THE LOW WILL KEEP AREA PRECIPITATION FREE THURSDAY...ALTHOUGH CLOUDS WILL LINGER EARLY IN THE DAY. UPPER FLOW BECOMES MORE ZONAL FRIDAY AND INTO THE WEEKEND AS SURFACE HIGH PRESSURE BUILDS OVER THE REGION. WARM ADVECTION SETS UP LATE SATURDAY NIGHT AND INTO SUNDAY AS HIGH PRESSURE MOVES EAST AND NEXT SHORTWAVE APPROACHES FROM THE GREAT LAKES. LIFT IS RATHER WEAK AT THIS TIME AND MOISTURE LIMITED HOWEVER...THERE IS A VERY LOW PROBABILITY OF LIGHT PRECIPITATION LATE SATURDAY NIGHT. SUNDAY WILL BE A BETTER CHANCE AS ADVECTION CONTINUES AND GULF MOISTURE MOVES INTO THE AREA. AS THE HIGH RETREATS TO THE NORTHEAST SATURDAY NIGHT INTO SUNDAY...COLD AIR DAMNING IS POSSIBLE AND MIXED PRECIPITATION WILL BE POSSIBLE INLAND AS COASTAL AREAS WARM IN THE SOUTHERLY FLOW. A COASTAL FRONT DEVELOPS SUNDAY INTO MONDAY AS A WEAK SOUTHERN STREAM SHORTWAVE MOVES OUT OF THE SOUTHWEST AND INTO THE GULF COAST REGION. THIS WAVE WILL DEVELOP A LOW ALONG THE COASTAL FRONT MONDAY INTO TUESDAY. STILL SOME UNCERTAINTY WITH THE TRACK OF LOW WITH THE ECMWF CLOSER TO THE COAST AND THE GFS MOVING THE LOW FARTHER OFF THE SOUTHEASTERN COAST AND KEEPING THE REGION ON THE NORTHWESTERN EDGE OF THE PRECIPITATION TUESDAY. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... HIGH IMPACT AVIATION WEATHER EVENT FOR TONIGHT AND WEDNESDAY. CONDITIONS DIMINISHING QUICKLY THIS EVENING. THIS EVENING...WINDS LIGHT SE 5-12 KT WITH LOWERING CEILINGS AND LIGHT RAIN MOVING ACROSS ENTIRE TERMINAL AREA. AFTER 00Z...CIGS AND VSBYS LOWER TO IFR OR LESS AND RAIN WILL BECOME MODERATE TO HEAVY AT TIMES. WINDS AND GUSTS INCREASE AFTER 05Z ESPECIALLY ACROSS THE NYC TERMINALS AND POINTS EAST. BY 08-09Z...GUSTS WILL REACH 35-40 KT. CAN NOT RULE OUT SOME ISOLATED GUSTS TO 45 KT IN CONVECTIVE ELEMENTS. IN ADDITION...A STRONG LOW LEVEL JET WILL RESULT IN WIND SHEAR SO HAVE INCLUDED IN THE TAFS AFTER 08Z. SPEEDS AT 2000 FT COULD APPROACH 70 KT...MAINLY EASTERN TERMINALS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. KLGA FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. KEWR FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. KTEB FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. KHPN FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. KISP FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE FORECAST. AMENDMENTS MAY BE NEEDED TO FINE TUNE ANY WIND SHIFTS AND TIMING OF LOWER CIGS AND PRECIPITATION THIS EVENING. .OUTLOOK FOR 18Z WEDNESDAY THROUGH MONDAY... .WED...LIFR...IMPROVING WEST TO EAST DURING THE AFTERNOON. +RA THROUGH MID MORNING. STRONG S/SE SURFACE WIND...HIGHEST NY METRO AND EAST...25-35G40-45KT EARLY AM. WIND LIGHTENS MIDDAY AS LOW PASSES JUST WEST OF NY METRO. WIND VEERS SW/W LATE AND INCREASES AGAIN. LLWS AND COMPRESSION LIKELY WITH 70+ KT AT FL020 IN THE EARLY AM. .WED NGT. MVFR...BECOMING VFR. CHC -SHSNRA. W/NW WINDS 20-25G35KT. .THU...VFR. NW WINDS 20-25G30-35KT EARLY SLOWLY DIMINISHING TO G20KT BY EVENING. .THU NGT-SAT...VFR. .SUN AND MON...MVFR CIG. -DZ / -RA. SE SFC FLOW 10-15 KT. && .MARINE... THE PRESSURE GRADIENT WILL QUICKLY TIGHTEN TONIGHT AHEAD OF AN ADVANCING STORM SYSTEM TRACKING FROM THE SOUTHEASTERN TO COASTAL MID ATLANTIC STATES TONIGHT...WITH WIND GUSTS TO GALE LEVELS DEVELOPING AFTER MIDNIGHT. A FEW GUSTS TO STORM FORCE MAY BE POSSIBLE TOWARD MORNING...MAINLY ON THE ERN OCEAN WATERS...BUT THESE SHOULD BE BRIEF AT BEST AND SO DID NOT UPGRADE ANY AREAS TO A STORM WARNING. WILL USE SPECIAL MARINE WARNINGS TO ADDRESS ANY WIND GUSTS OF 48 KT OR HIGHER IN ISOLATED STRONGER CONVECTION. SEAS COULD BUILD AS HIGH AS 16 FT ON THE ERN OCEAN WATERS WITH THE STRONGEST SOUTHERLY WINDS. THERE COULD BE A LULL IN WINDS FROM LATE WED MORNING INTO THE AFTERNOON...BUT THEN NW GALES ARE EXPECTED WED NIGHT INTO THU MORNING...WITH SEAS UP TO 15 FT EXPECTED WED NIGHT ON THE OCEAN AND AS HIGH AS 7 FT ON LONG ISLAND SOUND AS THE SURFACE LOW CONTINUES TO TRACK TO THE NORTH THROUGH CANADA AND HIGH PRESSURE BUILDS TO THE WEST. THE WIND WILL BE DIMINISHING THROUGH THE DAY THURSDAY...SUBSIDING BELOW GALE FORCE DURING THE AFTERNOON...AND THEN QUICKLY FALLING BELOW 25 KT DURING THURSDAY EVENING. VERY ROUGH SEAS ON THE OCEAN WATERS SUBSIDE DURING THURSDAY IN THE WEST TO NORTHWEST FLOW. BY LATE THURSDAY NIGHT SEAS ARE EXPECTED TO FALL BELOW 5 FT AS THE WESTERLY FLOW DIMINISHES. WIND AND SEAS REMAIN BELOW ADVISORY LEVELS FRIDAY INTO SUNDAY. DEPENDING ON THE STRENGTH OF THE WIND AROUND A DEPARTING HIGH AND A DEVELOPING TROUGH ALONG THE COAST...SEAS ON THE OCEAN WATERS MAY BUILD BACK UP TO SMALL CRAFT LEVELS LATE SUNDAY INTO SUNDAY NIGHT. && .HYDROLOGY... WIDESPREAD RAINFALL TOTALS FORECAST RANGE BETWEEN 2 AND 3 INCHES WITH LOCAL AMOUNTS UP TO 4 INCHES. DUE RECENT PROLONGED DRY CONDITIONS...MAIN STEM RIVER FLOODING IS NOT EXPECTED. HOWEVER...THERE IS ENOUGH CHANCE OF URBAN/AREAL/SMALL STREAM FLOODING...ESPECIALLY WHERE STORM DRAINS ARE CLOGGED BY LEAVES AND ESSENTIALLY WHERE THERE IS MORE RUNOFF....TO WARRANT A FLOOD WATCH FROM LATE TONIGHT INTO WED AFTERNOON. LIGHT PRECIPITATION IS POSSIBLE SUNDAY INTO TUESDAY...WITH A TOTAL OF UP TO A HALF INCH EXPECTED AT THIS TIME. && .TIDES/COASTAL FLOODING... A GALE FORCE SE FLOW WILL RAPIDLY DEVELOP AHEAD OF DEEPENING LOW PRESSURE LATE TONIGHT...BEFORE VEERING TO THE S WEDNESDAY MORNING. A STORM SURGE OF 2 TO 2 1/2 FT...LOCALLY 3 FT IS EXPECTED. THE PEAK SURGE COINCIDES BEST WITH THE TIMING OF THE MORNING HIGH TIDE CYCLE IN WESTERN LONG ISLAND SOUND AND PECONIC BAY. AN ADVISORY HAS BEEN ISSUED IN THESE LOCATIONS WITH COMBINED THREAT OF STORM TIDE...WAVE SPLASH-OVER...AND HEAVY RAIN CAUSING WIDESPREAD MINOR IMPACTS. ELSEWHERE...TIMING OF PEAK SURGE AND HIGH TIDE APPEARS TO BE OFFSET...WITH ONLY LOCALIZED ISSUES EXPECTED WITH WEDNESDAY MORNING HIGH TIDE DUE TO STORM TIDE AND HEAVY RAIN. A COASTAL FLOOD STATEMENT HAS BEEN ISSUED TO ADDRESS THIS THREAT. FOR THE LATE AFTERNOON/EVENING HIGH TIDE CYCLE...WITH FLOW EXPECTED TO BEGIN TURN OFFSHORE WOULD EXPECT SURGE VALUES TO BEGIN TO FALL RAPIDLY FROM AFTERNOON ON. THE ONLY AREA TO MONITOR WOULD BE THE SOUTH SHORE BACK BAYS WITH HIGH SURF LIMITING TIDAL DRAINAGE. HIGH SURF AND MINOR EROSION ISSUES ARE EXPECTED LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT FROM BATTERING SURF OF 7-11 FT. MAIN CONCERN WILL BE THE VULNERABLE DUNES AND BREACH LOCATIONS POST SANDY. A HIGH SURF ADVISORY HAS BEEN ISSUED TO ADDRESS THIS THREAT. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR CTZ005>012. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR CTZ008-011-012. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR CTZ007-009-010. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR CTZ009-010. NY...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR NYZ067>075-078>081-176>179. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST WEDNESDAY FOR NYZ078>081-177-179. COASTAL FLOOD ADVISORY FROM 6 AM TO 9 AM EST WEDNESDAY FOR NYZ079-081. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR NYZ071>075-176-178. COASTAL FLOOD ADVISORY FROM 5 AM TO 8 AM EST WEDNESDAY FOR NYZ071-073. WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NYZ067. HIGH SURF ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST WEDNESDAY NIGHT FOR NYZ080-081-178-179. NJ...FLOOD WATCH FROM MIDNIGHT EST TONIGHT THROUGH WEDNESDAY AFTERNOON FOR NJZ002-004-006-103>108. WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST WEDNESDAY FOR NJZ006. MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST THURSDAY FOR ANZ330-335-338-340-345-350-353-355. && $$ SYNOPSIS...GOODMAN/MET NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM...MET AVIATION...IRD MARINE...GOODMAN/MET HYDROLOGY...GOODMAN/MET TIDES/COASTAL FLOODING... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
415 PM EST TUE NOV 26 2013 .DISCUSSION... ...STRONG THUNDERSTORMS POSSIBLE AFTER SUNSET TONIGHT... ...TURNING MUCH COLDER WEDNESDAY NIGHT INTO THANKSGIVING MORNING... CURRENTLY/TONIGHT... CENTRAL FL REMAINS WELL INSIDE THE WARM SECTOR OF THE DVLPG GOMEX SYSTEM AS AFTN SFC DEWPOINTS REMAIN IN THE U60S/L70S...SFC TEMPS IN THE U70S/L80S. PREFRONTAL SQUALL LINE HAS DVLPD OVER THE ERN GOMEX PER LATEST SAT PICS/KTBW RADAR IMAGERY. RUC ANALYSIS SHOWS A POCKET OF ENHANCED H85-H50 VORTICITY DUE W OF TAMPA CONCURRENT WITH THE SQUALL LINE...AS WELL AS MODERATE TO STRONG UPR LVL DIVERGENCE AREAWIDE. H85-H50 STEERING FLOW INDICATES THE CORE ENERGY WILL TRACK N OF THE I-4 CORRIDOR LATER THIS EVENING...THOUGH LATEST KTBW TRAJECTORY SHOWS THE BULK OF THE RAINFALL WITH THE CONVECTIVE LINE LIFTING MORE TOWARD THE BIG BEND. OUTSIDE OF THE VORT MAX...MID LVL DYNAMIC SUPPORT IS QUITE WEAK WITH LITTLE IN THE WAY OF DEEP MID LYR VORTICITY OR OMEGA LIFT. MID LVL LAPSE RATES UNIMPRESSIVE AS WELL...LARGELY BTWN 5.5-6.0C/KM OVER THE SRN CWA...BLO 5.5C/KM NRN CWA. DESPITE SOME THINNING OF THE MID/UPR LVL CLOUD DECKS...KMLB/TMCO/KPBI RADARS INDICATE CONVECTION HAS STRUGGLED TO DVLP WITHIN THIS LCL ENERGY MINIMUM. DEEP MOISTURE REMAINS IN THE VCNTY OF THE SQUALL LINE WITH H100-H85 AND H85-H50 MEAN RH VALUES AOA 90PCT. MID LVL MOISTURE DIMINISHES A BIT OVER S FL THOUGH H85-H50 RH STILL BTWN 60-70PCT. MAX 0-3KM HELICITY VALUES BTWN 300-350 FROM OSCEOLA/BREVARD CO NWD...BUT EMBEDDED WITHIN A 30-40KT H85-H70 S/SW FLOW THAT WILL CARRY THE BULK OF IT OUT OF THE CWA BEFORE ANY SIG DESTABILIZATION CAN OCCUR. ON THE SYNOPTIC SCALE...THE NRN AND SRN STREAM SHORT WAVE TROFS HAVE MERGED...FORMING A FULL LATITUDE H85-H50 TROF EXTENDING FROM HUDSON BAY TO THE BAY OF CAMPECHE. THIS TROF WILL DIG STEADILY EWD OVERNIGHT...PULLING BOTH A STRONG COLD FRONT INTO THE FL PENINSULA. THE PREFRONTAL CONVECTIVE LINE WILL PUSH INTO CENTRAL FL THRU MID EVNG WITH AN INITIAL ROUND OF CONVECTION EXPECTED N OF SEBASTIAN INLET/LAKE KISSIMMEE THRU MIDNIGHT...THEN A SECOND ROUND TO THE S AFT 3AM. WHILE SVR WX THREAT HAS DIMINISHED...CANNOT RULE OUT HEAVY RAIN AND LCL STRONG WIND GUSTS AS TSRAS BLOW THROUGH. BULK OF THE COLD AIR ADVECTION WILL NOT OCCUR UNTIL AFT SUNRISE. DENSE CLOUD COVER AND STEADY S/SWRLY WINDS OVERNIGHT WILL KEEP MIN TEMPS 10-15F ABV CLIMO AVG...THE L/M60S N OF I-4...U60S/L70S TO THE SOUTH. WED-WED NIGHT...(MODIFIED PREV DISC) TIMING OF THE SYSTEM SHOULD CARRY THE BULK OF ITS CONVECTION CLEAR THE CWA BY DAYBREAK AS THE DEEPENING PARENT LOW RACES UP THE ERN SEABOARD. THE 500MB TROUGH WILL SWING THROUGH BY LATE MORNING... EFFECTIVELY ENDING ANY PRECIP FOR THE REGION BY MIDDAY. STRONG COLD AIR ADVECTION WILL COMMENCE QUICKLY BEHIND THE FRONT...BRINGING AN ARCTIC AIRMASS INTO CENTRAL FL. ITS LIKELY THAT A LAKE WIND ADVISORY WILL BE NEEDED FOR AT LEAST PART OF THE REGION...MAKING IT THE FOURTH DAY IN A ROW FOR SOME PLACES. THE COLD AIR ADVECTION AND LINGERING CLOUD COVER THROUGH LATE MORNING WILL PREVENT MAX TEMPS FROM RISING MUCH MORE THAN 5F ABOVE THE MORNING MINS. HIGH IN THE M/U60S ALONG AND N OF I-4...U60S/L70S TO THE S. MUCH OF THE AREA WILL REACH MAX TEMPS BEFORE NOON THEN HOLD STEADY OR DROP THRU THE AFTN. CLEARING SKIES AND STRONG COLD/DRY AIR ADVECTION WILL DROP OVERNIGHT MINS INTO THE U30S/L40S MOST OF THE CWA W OF I-95. OCEAN INFLUENCE SHOULD KEEP AREAS E OF I-95 IN THE M/U40S THRU DAYBREAK THU...STILL A SOLID 20-25F DEG COLDER THAN WED MORNING MINS. THANKSGIVING DAY-SUNDAY...(PREV DISC) HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT...QUICKLY SPREADING OUT ACROSS THE DEEP SOUTH AND MID-ATLANTIC BY FRIDAY...BEFORE BEING REINFORCED BY A SECONDARY HIGH ACROSS NEW ENGLAND INTO THE WEEKEND. BREEZY NORTH TO NORTH-NORTHEAST FLOW WILL START OFF THE THANKSGIVING HOLIDAY BEFORE RETURNING TO WHAT HAS BECOME THE DEFAULT PATTERN OF LATE...BREEZY EAST-NORTHEAST FLOW INTO THE WEEKEND. THE NORTHEAST WIND SURGE AS THE HIGH BEGINS TO BUILD INTO THE ATLANTIC LATE ON THURSDAY WILL REINTRODUCE ISOLATED LOW TOPPED ATLANTIC SHOWERS INTO THE FORECAST THURSDAY NIGHT...AFFECTING COASTAL AREAS FROM FRIDAY ONWARDS THANKSGIVING DAY WILL BE COOL AND BLUSTERY WITH HIGHS IN THE MID 60S IN MOST LOCATIONS. AS THE FLOW REGAINS ITS ONSHORE COMPONENT...TEMPERATURES WILL MODERATE INTO THE WEEKEND WITH HIGHS IN THE MID-UPPER 70S AND LOWS IN THE LOW-MID 50S INLAND/MID-UPPER 60S BREVARD/TREASURE COAST BY SATURDAY AND SUNDAY. && .AVIATION... THRU 27/00Z...S/SE SFC WIND ARND 15KTS WITH G20-25KTS...PREVAILING VFR VSBYS WITH BRIEF PDS BTWN 3-5SM IN ISOLD SHRAS...VRBL CIGS ALL SITES PREVAILING BTWN FL080-100 WITH OCNL PDS BTWN FL020-030 IN -RA. BTWN 27/00Z-27/04Z...WINDS S/SW 10-15KTS WITH 30-35KT SW LLWS PSBL ALL SITES...SCT NMRS MVFR SHRAS/SCT IFR TSRAS W OF KMLB-KOBE....SCT MVFR SHRAS/ISOLD IFR TSRAS E OF KMLB-KOBE. BTWN 27/04Z-27/12Z...SQLN WILL PUSH THRU E CENT FL WITH 35-40KT W/SW LLWS PSBL ALL SITES. STRONG WIND GUSTS ABOVE 35 KNOTS AND +RA REDUCING VSBYS/CIGS TO IFR/LIFR CONDS WITH THE PASSAGE OF THE LINE. && .MARINE... TONIGHT...SCA CONDITIONS TO CONTINUE. LCL DATA BUOY/C-MAN STATIONS INDICATE SFC/BNDRY LYR WINDS HAVE SHIFTED TO THE S...STILL HOLDING ARND 20KTS WITH GUSTS ARND 30KTS. LITTLE CHANGE TO SEAS...6-8FT NEARSHORE AND 8-10FT OFFSHORE WITH DOMINANT PDS AOB 8SEC. STORM SYSTEM LIFTING INTO THE DEEP SOUTH WILL FORCE SFC/BNDRY LYR WINDS TO VEER SW OVERNIGHT...INCREASING TO GALE/NEAR GALE FORCE N OF THE CAPE AFT SUNSET. SCA/GALE WARNING TIMING AND CONFIGURATION LOOK GOOD. WED-WED NIGHT...(PREV DISC) DEEPENING LOW PRESSURE SYSTEM WILL MOVE ACROSS N FLORIDA AND UP THE EASTERN SEABOARD EARLY ON WEDNESDAY WITH A COLD FRONT SWEEPING THROUGH THE STATE BEFORE MIDDAY. SOUTHWEST-WEST WINDS WILL BE STRONGEST EARLY IN THE DAY WITH THE LOW AT ITS CLOSEST APPROACH WITH SPEEDS 25-30KTS NORTH OF THE CAPE AND 20-25KTS SOUTH. WITH FREQUENT GUSTS TO GALE FORCE EXPECTED...A GALE WARNING WILL BE HOISTED FOR THE OFFSHORE WATERS NORTH OF SEBASTIAN INLET THROUGH MIDDAY. WINDS SLOWLY DECREASE THROUGH THE AFTERNOON BECOMING NW 15-20KTS BY THE EVENING...AND NORTH OVERNIGHT. SEAS 4-6FT NEARSHORE AND 7-9FT OFFSHORE EARLY...SLOWLY DIMINISHING TO 4-7FT BY LATE NIGHT. THE PREVAILING OFFSHORE WIND COMPONENT WILL GENERATE ROUGH AND HAZARDOUS SHORT PERIOD SEAS OVER THE OPEN ATLC WITHIN A FEW MILES OF SHORE. ROUGH CONDITIONS WILL CONTINUE OVERNIGHT DUE TO THE OPPOSING DIRECTIONS OF THE NRLY WIND AND THE SRLY GULF STREAM. THU-SUN...(PREV DISC) SURFACE HIGH BUILDING ACROSS THE DEEP SOUTH BEHIND THE FRONT WILL BE DOMINANT FEATURE THROUGH THE END OF THE WEEK INTO THE WEEKEND. NORTH WINDS EARLY ON THURS BECOME NORTHEAST BY THE AFTERNOON...BEFORE VEERING TO THE EAST-NORTHEAST FRI-SUNDAY. SPEEDS GENERALLY 15-20KTS. INCREASING ONSHORE COMPONENT TO THE FLOW WILL PUSH A STEADY SWELL INTO THE COAST WITH SEAS 4-6FT ON FRIDAY BUILDING TO 8-9FT OFFSHORE BY SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... DAB 64 67 40 64 / 90 20 0 10 MCO 65 69 40 66 / 90 10 0 0 MLB 68 71 46 68 / 90 30 0 10 VRB 71 73 46 69 / 80 40 0 10 LEE 61 66 36 64 / 90 10 0 0 SFB 65 68 38 65 / 90 10 0 0 ORL 64 68 40 66 / 90 10 0 0 FPR 71 73 46 69 / 80 40 0 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST WEDNESDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY FROM 1 PM TO 7 PM EST WEDNESDAY FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. GALE WARNING FROM 10 PM THIS EVENING TO 1 PM EST WEDNESDAY FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
345 PM EST TUE NOV 26 2013 ...ISOLATED SEVERE WEATHER POSSIBLE THIS EVENING... ...HAZARDOUS BOATING CONDITIONS THROUGH WEDNESDAY NIGHT... ...HIGH RISK OF RIP CURRENTS ALONG AREA BEACHES THROUGH WEDNESDAY... ...FREEZE WATCH FOR PORTIONS OF THE NATURE COAST WEDNESDAY NIGHT... .SYNOPSIS... 20Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN AMPLIFIED AND HIGHLY ENERGETIC UPPER LEVEL PATTERN EVOLVING ACROSS THE CONUS. FLOW RIDGES SHARPLY OVER THE PACIFIC COAST AND INTER-MOUNTAIN WEST BEFORE DIVING BACK SOUTH INTO DEEP LONGWAVE TROUGHING COVERING THE REMAINDER OF THE NATION. THIS LONGWAVE TROUGH IS RATHER COMPLEX WITH BOTH A STRONG NORTHERN STREAM AND SOUTHERN STREAM IMPULSE EMBEDDED WITHIN. THE NORTHERN STREAM ENERGY IS DROPPING QUICKLY SOUTHEASTWARD OVER THE UPPER MIDWEST/GREAT LAKES WHILE THE SOUTHERN STREAM IMPULSE IS CURRENTLY EJECTING EASTWARD ALONG THE NORTHERN GULF COAST. IT IS THIS POTENT SOUTHERN STREAM IMPULSE WHICH WILL BE THE BIG PLAYER IN OUR WEATHER OVER THE NEXT 12-24. CURRENTLY AT THE SURFACE...THE FLORIDA PENINSULA RESIDES WITH A ZONE OF MODERATE SOUTHEASTERLY TO SOUTHERLY FLOW WITHIN A DEFINED WARM SECTOR SOUTH AND EAST OF A DEEPENING AREA OF LOW PRESSURE OVER SOUTHERN AL/GA. FROM THIS LOW...A COLD FRONT TRAILS SOUTHWARD ACROSS THE CENTRAL GULF OF MEXICO AND WILL MOVE QUICKLY EASTWARD TO CROSS OUR FORECAST AREA LATER THIS EVENING AND EARLY MORNING HOURS. REGIONAL RADARS SHOWING WIDESPREAD SHOWERS/THUNDERSTORMS PUSHING TOWARD THE FLORIDA WEST COAST WITHIN THE ZONE OF IMPRESSIVE SYNOPTIC ASCENT AHEAD OF THE APPROACHING SOUTHERN STREAM IMPULSE AND SURFACE FOCUS AHEAD OF THE COLD FRONT. SAW SOME SUNNY BREAKS TODAY WHICH ALLOWED DECENT SURFACE HEATING AND THE DEVELOPMENT OF SURFACE BASED INSTABILITY. THIS INSTABILITY IS BEING REALIZED WITH A SCATTERING OF MAINLY SHOWERS OVER THE LAND AREAS...HOWEVER THE REAL SHOW IN TERMS OF RAIN/THUNDER IS STILL OVER THE WATER AND SCHEDULED TO REACH THE COAST BY EARLY EVENING. && .SHORT TERM (EARLY EVENING THROUGH THURSDAY NIGHT)...THE POTENTIALLY MORE SIGNIFICANT WEATHER IS BEGINNING TO APPROACH FROM THE EASTERN GULF OF MEXICO. AS WE HEAD INTO THE EVENING HOURS...LARGE SCALE FORCING FOR ASCENT ASSOCIATED WITH DCVA/HEIGHT FALLS WILL OVERSPREAD THE AREA. GFS/ECMWF BOTH SHOW A BROAD EXPANSE OF DEEP LAYER QG FORCING IN PLACE THIS EVENING. THIS IS ONE OF THE MORE POTENT MID/UPPER LEVEL IMPULSES THAT WE HAVE SEEN MOVE ACROSS THE NE GULF IN SOME TIME. UPPER LEVEL PV ANOMALY ASSOCIATED WITH THIS IMPULSE IS VERY IMPRESSIVE WITH THE DYNAMIC TROPOPAUSE FOLDED DOWN ALMOST TO 600MB RESULTING IN AN EQUALLY IMPRESSIVE MID/UPPER LEVEL JET STRUCTURE. SURFACE LOW REFLECTION AS A RESULT SHOULD CONTINUE TO DEEPEN THROUGH THE EVENING AHEAD OF THIS FEATURE AS IT CROSSES INTO SOUTHERN GA. THE COLD FRONT WILL ALSO INTENSIFY/SHARPEN WITH TIME ADDING ADDITIONAL LOWER LEVEL CONVERGENCE FOCUS. ALL THAT BEING SAID...RAIN CHANCES ARE CATEGORICAL 80% OR HIGHER FOR JUST ABOUT ALL COASTAL ZONES THIS EVENING AND INLAND ZONES LATE THIS EVENING INTO THE EARLY MORNING HOURS. RAIN CHANCES WILL TAPER OFF QUICKLY WITH THE PASSAGE OF THE COLD FRONT FROM WEST TO EAST DURING THE SECOND HALF OF THE NIGHT AND HAVE ALL RAIN CHANCES (EVEN FOR OUR FAR EASTERN ZONES) REMOVED BY SUNRISE TOMORROW MORNING. THE CONVECTIVE START AND END TIMES AGREE WELL WITH THE ENSEMBLE SUITE OF LOCAL/NATIONAL HIGH RESOLUTION MODELS AND ALSO THE HOPWRF ENSEMBLES BEING RUN OVER THE SE CONUS TODAY. SEVERE THREAT...DESPITE THE EXPECTED WIDESPREAD COVERAGE OF SHOWER AND STORMS DUE TO THE STRONG SYNOPTIC FORCING...THE OVERALL SEVERE THREAT SHOULD BE ISOLATED IN NATURE. THE STORM PREDICTION CENTER HAS OUTLOOKED MUCH OF OUR AREA IN A SLIGHT RISK FOR SEVERE WEATHER AND AGREE WITH THIS ASSESSMENT. A NEW TORNADO WATCH HAS JUST BEEN ISSUED TO INCLUDE SARASOTA...MANATEE...PINELLAS...HILLSBOROUGH...POLK... PASCO...HERNANDO...SUMTER...CITRUS...AND LEVY COUNTIES. DEEP LAYER 0-6KM BULK SHEAR (35-40KTS) AND MLCAPE ARE NOT OVERLY IMPRESSIVE... BUT CERTAINLY SUFFICIENT FOR ORGANIZED CONVECTION. MID-LEVEL LAPSE RATES ARE ON THE POOR SIDE FOR MUCH OF THE EVENT...HOWEVER THE LACK OF OVERALL BUOYANCY COULD BE OFFSET SOMEWHAT BY THE TENDENCY FOR THE UPDRAFTS TO ROTATE. LOW LEVEL JET WILL BE STRONGEST 40-50KTS OVER THE NATURE COAST ZONES...AND THEN WEAKEN WITH SOUTHWARD EXTENSION. ALL THAT BEING SAID...THE POTENTIAL CERTAINLY EXISTS FOR ISOLATED SEVERE WEATHER. THE MAIN THREAT WILL BE FOR DAMAGING STRAIGHT-LINE WINDS. AN ISOLATED TORNADO IS POSSIBLE AS WELL. THE BEST SETUP FOR AN ISOLATED TORNADO LOOKS TO EXIST ALONG THE I-4 CORRIDOR AND NORTHWARD THROUGH THE NATURE COAST ZONES WHERE THE MORE PRONOUNCED LOW LEVEL JET EXISTS...RESULTING IN 0-1KM SHEAR OF 25-30KTS. WEDNESDAY...UPPER SHORTWAVE TAKES ON AN INCREASINGLY NEGATIVE TILT AND ROTATES TO THE NORTHEAST OF THE AREA DURING THE MORNING HOURS. RAIN WILL BE OVER WITH THE COLD FRONT OFF TO OUR EAST BY SUNRISE. DEEP LAYER MOISTURE WILL ALSO QUICKLY EXIT ALLOWING FOR GENERALLY CLEARING SKIES. HOWEVER...CAA IN THE WAKE OF THE FRONT OVER THE GULF WILL LIKELY PRODUCE SOME COLD AIR STRATOCU THAT MAY MIGRATE ONSHORE FROM TIME TO TIME (ESPECIALLY FROM PINELLAS COUNTY SOUTHWARD). THOSE TRAVELING FOR THE THANKSGIVING HOLIDAY ON WEDNESDAY ALONG I-4 OR FLORIDA I-75 CORRIDORS SHOULD EXPERIENCE FAIR WEATHER WITH A GUSTY NW WIND. HIGH TEMPERATURES WILL BE COOLER WITH MAINLY 60S FROM TAMPA BAY NORTHWARD AND AROUND 70 FURTHER SOUTH. ALONG AREA BEACHES THE STRONG ONSHORE FLOW WILL PRODUCE LARGE BREAKING WAVES AND A HIGH RISK OF RIP CURRENTS THROUGH THE DAY. WEDNESDAY NIGHT... LIKELY THE COLDEST NIGHT OF THE SEASON SO FAR ON THE WAY. A VERY DRY AIRMASS AND NORTHERLY FLOW DRAINING DOWN THE PENINSULA WILL ALLOW FOR TEMPERATURES TO STEADILY FALL THROUGH THE NIGHT. BY DAWN ON THANKSGIVING MORNING THE CURRENT FORECAST SHOWS WIDESPREAD LOW TEMPS IN THE MID/UPPER 30S TO LOW 40S. COLDER LOCATIONS OF HILLSBOROUGH... POLK...AND PASCO COUNTY MAY BRIEFLY REACH THE LOWER 30S...AND EVEN BETTER CHANCES FOR A PERIOD OF SUB-FREEZING (UPPER 20S/LOW 30S) FURTHER NORTH ALONG THE NATURE COAST. THE CURRENT FORECAST TEMPERATURES ARE SEVERAL DEGREES ABOVE THE MAV GUIDANCE AS EXPERIENCE SHOWS A COLD BIAS TO THE STATISTICAL GUIDANCE WITH REGARDS TO ADVECTION EVENTS. EVEN WITH THIS BIAS ADJUSTMENT...A FREEZE WATCH IS APPROPRIATE...AND HAS BEEN ISSUED FOR HERNANDO... SUMTER...CITRUS...AND LEVY DURING THE EARLY MORNING HOURS OF THURSDAY (THANKSGIVING MORNING). THANKSGIVING DAY/NIGHT... A COLD START...BUT OTHERWISE A PLEASANT HOLIDAY UPCOMING. THE SYNOPTIC PATTERN LOOKS BENIGN WITH ZONAL FLOW ALOFT AND A NORTHEAST LOW LEVEL FLOW ON THE SOUTH SIDE OF SURFACE RIDGING. PLENTY OF SUN IN THE MORNING WILL GIVE WAY TO A MIX OF SUN AND CLOUDS FOR THE AFTERNOON AND TEMPERATURES RISING INTO THE 60S FOR MOST SPOTS (PERHAPS NEAR 70 AROUND FORT MYERS). INCREASING LOW LEVEL MOISTURE OFF THE ATLANTIC BY THURSDAY NIGHT SHOULD PREVENT ANY FREEZE CONCERNS AS TEMPERATURES LOOK TO BE A GOOD 5-10+ DEGREES WARMER FOR LOWS THAN ON THURSDAY MORNING. && .LONG TERM (FRIDAY-MONDAY)... SYNOPTIC MID LEVEL PATTERN THROUGH THE WEEKEND SHOWS A ZONAL FLOW IN PLACE FRIDAY WITH A WEAK SHORT WAVE SHIFTING THROUGH THE PENINSULA ON SATURDAY. ECMWF IS SHOWING A MORE AMPLIFIED TROUGH DIGGING SOUTH THROUGH THE SOUTHEAST US ON MONDAY WITH THE GFS DEPICTING A MUCH WEAKER WAVE. AT THE SURFACE...MODELS ARE IN GOOD AGREEMENT THROUGH SUNDAY SHOWING HIGH PRESSURE STRETCHED ACROSS THE EAST COAST BEFORE BEING FORCED EASTWARD BY THE NEXT APPROACHING COLD FRONT. DRY PATTERN EXPECTED TO SETTLE IN THROUGH SUNDAY MORNING WHICH WILL LIMIT RAIN CHANCES. EVEN WITH A MID LEVEL SHORT WAVE SHIFTING THROUGH THE STATE ON SATURDAY STRONG SURFACE RIDGING AND LACK OF MOISTURE WILL HELP DIMINISH CONVECTION. RIDGE BEGINS TO WEAKEN ON SUNDAY AND MONDAY WITH THE RETURN OF A MORE SOUTHEASTERLY FLOW. AS MOISTURE BEGINS TO ADVECT OVER THE STATE WE WILL SEE RAIN CHANCES BEGIN TO SLIGHTLY INCREASE AT THE TAIL END OF THE LONG TERM PERIOD. TEMPS WILL GRADUALLY INCREASE TO MORE SEASONAL VALUES THROUGH WEEKEND. && .AVIATION... BKN CIGS WITH VCNTY SHRA OR TSRA THIS AFTERNOON GIVE WAY TO MVFR IN TSRA BEGINNING 00Z-04Z...WITH OCNL IFR...AND ENDING 06Z-08Z. VCNTY SHRA OR -RA BECOME JUST BKN VFR CIGS AFTER 12Z. GUSTY SOUTHERLY WINDS GRADUALLY SHIFT TO WESTERLY BY SUNRISE. && .MARINE... LOW PRESSURE WILL PASS TO OUR NORTH ACROSS SOUTHERN ALABAMA AND GEORGIA THIS EVENING...AND TO THE MID ATLANTIC STATES BY WEDNESDAY. A STRONG COLD FRONT TRAILING FROM THIS LOW WILL MOVE ACROSS THE EASTERN GULF OF MEXICO THIS EVENING AND OVERNIGHT. WINDS WILL SHIFT NORTHWEST IN THE WAKE OF THE FRONT WITH GUSTS TO GALE FORCE POSSIBLE AFTER MIDNIGHT THROUGH WEDNESDAY MORNING. HIGH PRESSURE WILL ALSO BUILD NORTH OF THE AREA IN THE WAKE OF THE FRONT AND REMAIN IN PLACE THROUGH FRIDAY. WINDS AND SEAS WILL REMAIN NEAR ADVISORY CONDITIONS THROUGH FRIDAY DUE TO A TIGHT PRESSURE GRADIENT TO THE SOUTH OF THE HIGH CENTER. && .FIRE WEATHER... A STRONG COLD FRONT WILL CROSS THE REGION OVERNIGHT WITH A MUCH COOLER AND DRIER AIRMASS ARRIVING DURING THE DAY ON WEDNESDAY. WINDS WILL BE QUITE GUSTY FROM THE NORTHWEST DURING WEDNESDAY RESULTING IN HIGH DISPERSION INDICES ACROSS THE FORECAST AREA. HOWEVER...AT THIS TIME...NO CRITICAL LEVELS OF RELATIVE HUMIDITY ARE ANTICIPATED. WINDS WILL BECOME LESS GUSTY FROM THE NORTHEAST ON THURSDAY AND A BRIEF PERIOD OF RELATIVE HUMIDITY BELOW 35 PERCENT IS POSSIBLE DURING THE AFTERNOON...ESPECIALLY TO THE NORTH OF THE I-4 CORRIDOR. && .PRELIMINARY POINT TEMPS/POPS... TPA 66 69 39 67 / 100 10 0 0 FMY 70 74 43 71 / 90 10 0 0 GIF 63 69 37 68 / 90 10 0 0 SRQ 66 71 42 67 / 90 10 0 0 BKV 62 67 34 66 / 100 10 0 0 SPG 66 69 46 66 / 100 10 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RIP CURRENT RISK THROUGH THURSDAY MORNING FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. HIGH SURF ADVISORY UNTIL 7 AM EST THURSDAY FOR CHARLOTTE- HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA. FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR CITRUS-HERNANDO-LEVY-SUMTER. GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM- TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM. SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR TAMPA BAY WATERS. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA AVIATION...RUDE LONG TERM...BARRON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 PM EST TUE NOV 26 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 505 PM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS REVEALS A WELL-DEFINED MID/UPPER LEVEL SHORTWAVE ROTATING EAST ACROSS THE UPPER GREAT LAKES THIS AFTERNOON. AT THE SFC...LOW PRES WAS LOCATED OVER NRN LAKE HURON WITH A COLD FRONT EXTENDING SE THROUGH LOWER MI AND A TROUGH STRETCHING TO THE NORTHWEST OVER NRN ONTARIO. 700-300 QVECTOR CONV OUT AHEAD OF THE SHRTWV SUPPORTED AN AREA OF SHSN ACROSS WEST AND CNTRL UPPER MI EARLIER TODAY WITH SOME HEAVIER LES REPORTED ALONG AND BEHIND INITIAL FRONTAL PASSAGE. SOME AREAS NEAR WAKEFIELD/BESSEMER REPORTED 8-9 INCHES OF LAKE ENHANCED SNOW ALREADY FROM THE SNOW THAT STARTED EARLY THIS MORNING WHILE MODERATE TO HEAVY LES WAS ALSO REPORTED OVER PORTIONS OF HOUGHTON...NW MQT AND WRN ALGER COUNTIES. EXPECT LES TO CONTINUE MODERATE TO HEAVY AT TIMES TONIGHT INTO WEDNESDAY AS THE TROUGH JUST NORTH OF LAKE SUPERIOR MOVES SOUTH ACROSS THE AREA LATE THIS EVENING AND SHIFTS WINDS FROM NW TO MORE NNE DIRECTION OVER LAKE SUPERIOR. THIS WILL PUSH HEAVIER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY WITH ANOTHER DOMINANT BAND LIKELY SETTING UP OVER THE PORCUPINE MTNS/IRONWOOD AREA. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR JUST AFT 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. EXPECT THE GREATEST SNOWFALL RATES NEAR MARQUETTE LATE THIS EVENING SHIFTING INTO THE HIGHER TERRAIN WEST OF MARQUETTE OVERNIGHT INTO WEDNESDAY AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLAND/PORCUPINE MTNS WITH SNOWBANDS ORIGINATING NEAR THUNDER BAY AND PERHAPS CONNECTING WITH LAKE NIPIGON IN STRONG MOIST CYCLONIC NNE FLOW. WITH BUFR SNDGS INDICATING THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...EXPECT SLR VALUES IN THE 25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. THE SNOW AND BLOWING SNOW WILL MAKE ROADS HAZARDOUS AND TRAVEL DIFFICULT TONIGHT INTO WEDNESDAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 7 INCH RANGE OVER THE HIGHER TERRAIN OF WRN MQT COUNTY AND FROM WHITE PINE TO BERGLAND WEST TO IRONWOOD. WEDNESDAY....EXPECT ANOTHER 2-4 OF SNOW OVER GOGEBIC-ONTONAGON COUNTIES WITH ANOTHER 3-6 INCHES OVER THE HIGHER TERRAIN OF WRN MQT COUNTY. GIVEN EXPECTED AMOUNTS AND BLOWING SNOW POTENTIAL HAVE DECIDED TO UPGRADE GOGEBIC-ONTONAGON TO AN LES WARNING THROUGH 18Z WED WHILE I ALSO UPGRADED MQT TO LES WARNING FOR TONIGHT THROUGH WEDNESDAY. FOR NOW LEFT LES ADVISORIES GOING FOR KEWEENAW-NRN HOUGHTON INTO TONIGHT AND FOR BARAGA COUNTIES AND ALGER COUNITES INTO WED AFTERNOON. WRN ALGER WILL NEED TO BE CLOSELY MONITORED TONIGHT AS HEAVIER LES BANDS COULD PUSH AMOUNTS NEAR WARNING CRITERIA. INFLUZ OF DRIER AIR AND WEAKENING NNE FLOW SHOULD ALLOW LES TO TAPER OFF WED AFTERNOON FROM WEST TO EAST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 416 PM EST TUE NOV 26 2013 UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST LOCATIONS. THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT THINKING REMAINS. OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER 20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE DISTURBANCE. EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE 30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1242 PM EST TUE NOV 26 2013 KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25 MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO WEDNESDAY. KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES. KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST TUE NOV 26 2013 WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE 2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR. LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER MAINLY E LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004- 006. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084. LAKE SUPERIOR... GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST WEDNESDAY FOR LSZ265. GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST WEDNESDAY FOR LSZ264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EST TUE NOV 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW. HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT. TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO -17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING. TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 6 INCH RANGE. WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE. SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON TRACK. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 416 PM EST TUE NOV 26 2013 UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE MAIN LOW NEAR HUDSON BAY THROUGH EARLY FRIDAY...WITH DISTURBANCES CONTINUING TO SWING ACROSS THE REGION. THE THERMOMETERS OUTSIDE WILL BE BELOW TURKEY THAWING CONDITIONS...BOTTOMING OUT IN THE TEENS FOR MOST LOCATIONS. THOSE WHO ENJOY SNOW WILL BE THANKFUL FOR MORE SNOW SHOWERS THURSDAY. THE SFC LOW ACROSS SD AT 00Z THURSDAY WILL WEAKEN OVER MN AND IA WEDNESDAY NIGHT...BEFORE SLOWLY CROSSING UPPER MI AND LAKE MI THURSDAY INTO FRIDAY. CURRENT THINKING IS FOR THE BEST BANDS OF SNOW TO BE OFF-SHORE OVER W LAKE SUPERIOR...STRETCHING THROUGH KEWEENAW COUNTY AND TROUGH S CENTRAL LAKE SUPERIOR. COULD HAVE 2-5IN OF LAKE EFFECT SNOW FOR KEWEENAW COUNTY. THE NAM AND OTHER SMALLER SCALE MODELS ARE A LITTLE MORE BULLISH ON THE SNOW/QPF ACCUMULATION OVER THE TIP OF THE KEWEENAW PENINSULA. MAY NEED AN ADVISORY IF CURRENT THINKING REMAINS. OTHERWISE...FRIDAY WILL BE MARKED BY WAA. LEFTOVER POCKETS OF COLD AIR FRIDAY WILL KEEP TEMPERATURES MAXING OUT IN THE MID TO UPPER 20S. 850MB TEMPS SHOULD RISE INTO THE -7 TO -13C RANGE BY 00Z SATURDAY. THE 500MB RIDGE BUILDING IN FRIDAY AFTERNOON AND EVENING WILL BE SHORT LIVED. THE NEXT TROUGH SET UP FROM MANITOBA THROUGH THE N PLAINS AT 06Z SATURDAY SHOULD SLOWLY EDGE ACROSS MANITOBA AND THE UPPER GREAT LAKES SATURDAY THROUGH EARLY SUNDAY. WHILE POPS WILL INCREASE BACK TO CHANCES AGAIN SATURDAY INTO SATURDAY NIGHT THERE LOOKS TO BE LITTLE MOISTURE TO WORK WITH...GIVEN THE ORIGIN OF THE DISTURBANCE. EXPECT BREEZY CONDITIONS E ON SATURDAY...WITH WINDS JUST ABOVE THE SFC OUT OF THE SSW AROUND 40-45KTS. SFC TEMPS SHOULD RETURN TO THE 30S CWA WIDE FOR THE 1ST TIME SINCE MONDAY. THE NEXT CLIPPER-LIKE SYSTEM SHOULD BE SWINGING IN FROM THE NW SATURDAY AFTERNOON. TIMING IS STILL A CONCERN...WITH THE 12Z RUNS OF THE ECMWF AND GFS DIFFERING BY 350MI AT 18Z SATURDAY. THE ECMWF HAS IT ACROSS S CENTRAL ONTARIO...WHILE THE LOW OFF THE GFS IS NEAR THE MANITOBA/ONTARIO BORDER. OF MORE OF A CONCERN IS THEIR HANDLING OF THE NEXT...MORE SIGNIFICANT LOOKING SYSTEM...IN THE FORM OF A 500MB LOW SINKING ACROSS THE PACIFIC NW MONDAY. STILL...THE IMPACTS OF THAT ONE WILL NOT REALLY BE NOTICED UNTIL CLOSER TO MID WEEK...WITH THE ASSOCIATED SFC LOW PUSHING ACROSS THE PLAINS STATES TUESDAY AS THE 500MB LOW SLIDES ACROSS MT. WILL HAVE TO WAIT TO SEE WHAT SORT OF IMPACTS THIS ONE WILL HAVE ACROSS THE UPPER GREAT LAKES OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1242 PM EST TUE NOV 26 2013 KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25 MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO WEDNESDAY. KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES. KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST TUE NOV 26 2013 WEAK LOW PRESSURE OVER S ONTARIO WILL MOVE E OVERNIGHT AS HIGH PRESSURE OVER THE N PLAINS TONIGHT SLIDES INTO THE GREAT LAKES REGION...WEAKENING SLIGHTLY BY WEDNESDAY AFTERNOON. IN BETWEEN THESE 2 SYSTEMS...N GALES TO 35KTS ARE EXPECTED OVER MAINLY CENTRAL AND E LAKE SUPERIOR TONIGHT...CONTINUING WITH MAINLY GALE FORCE GUSTS WEDNESDAY OVER E PORTIONS OF LAKE SUPERIOR. LOW PRESSURE OVER THE SE U.S. TONIGHT WILL MOVE NORTHEASTWARD INTO THE NEW ENGLAND STATES BY WEDNESDAY EVENING WHILE DEEPENING...WHICH WILL KEEP A TROUGH OVER THE LOWER LAKES. FOR THURSDAY INTO FRIDAY...ANOTHER WEAK TROUGH SHOULD CROSS LAKE SUPERIOR...MERGING WITH A HIGH OVER LAKE ONTARIO BY FRIDAY EVENING. AS THE HIGH MOVES E TOWARDS THE ATLANTIC SATURDAY AFTERNOON INTO SUNDAY...ANOTHER WEAK TROUGH WILL CROSS LAKE SUPERIOR. ANOTHER PERIOD OF STRONGER WINDS...OUT OF THE S NEAR 30KTS...WILL BE POSSIBLE SATURDAY OVER MAINLY E LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ004- 006. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ084. LAKE SUPERIOR... GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST WEDNESDAY FOR LSZ265. GALE WARNING FROM MIDNIGHT TONIGHT TO 5 AM EST WEDNESDAY FOR LSZ264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
108 PM EST TUE NOV 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 516 AM EST TUE NOV 26 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A WELL DEFINED UPSTREAM MID/UPPER LEVEL LOW/SHORTWAVE TROUGH FROM NW OF LAKE SUPERIOR INTO NW MN. AT THE SFC...LOW PRES WAS LOCATED NE OF LAKE SUPERIOR(NEAR WAWA ONTARIO) WITH A COLD FRONT EXTENDING THROUGH WHITEFISH BAY INTO NW LOWER MI AND A TROUGH STRETCHING TO THE WEST. 700-300 QVECTOR CONV AHEAD OF THE SHRTWV SUPPORTED SCT -SHSN/FLURRIES FROM NE MN INTO CNTRL UPPER MI. RADAR ALSO INDICATED AN INCREASE IN LES FROM FROM NEAR BIG BAY EASTWARD ALIGNED WITH 280-290 LOW LEVEL FLOW. HOWEVER...WEBCAMS AND SFC OBS OVER WRN UPPER MI DID NOT SHOW A SIGNFICANT INCREASE IN SNOW INTENSITY OVERNIGHT. TODAY...EXPECT LES TO INCREASE THIS MORNING OVER THE WEST AS THE MID LEVEL LOW SLIDES TO THE SOUTHEAST WITH 850/700 MB TEMPS DROPPING TO -17C/-25C...INCREASING 850-700 MOISTURE AND CLIMBING INVERSION HEIGHTS. THE HIGHER RES MODELS SUGGEST THAT THE MOST FAVORABLE LOW LEVEL CONV AND HIGHER LES POTENTIAL IN THE VEERING WIND PATTERN WILL SET UP BETWEEN TWIN LAKES AND IRONWOOD BEFORE WINDS BEOMCE MORE NNW LATER IN THE AFTERNOON. HIGHER TERRAIN LOCATIONS SHOULD SEE SNOW AMOUNTS IN THE 3 TO 6 INCH RANGE WITH SOME LOCALLY HIGHER AMOUNTS POSSIBLE. OVER THE EAST...THE WNW FLOW SHOULD CONFINE THE STRONGER LES BANDS TO AREAS NEAR THE LAKE EAST OF MUNISING. TONIGHT...THERE IS STILL UNCERTAINTY WITH HOW QUICKLY WINDS WILL VEER OVER THE CNTRL AND EAST WHICH WILL PUSH THE STRONGER LES BANDS INTO MARQUETTE COUNTY AND WRN ALGER COUNTY. MOST OF THE MODELS SUGGEST THAT THIS WILL OCCUR AT OR LATER THAN 00Z WHEN THE MID LEVEL TROUGH AXIS MOVES INTO ERN UPPER MI. THE NNW WINDS ARE EXPECTED TO GRADUALLY VEER TO THE NNE TONIGHT. SO...THE GREATEST SNOWFALL RATES NEAR MARQUETTE ARE EXPECTED LATE THIS EVENING AND THEN WILL SHIFT INTO THE HIGHER TERRAIN TO THE WEST AS THE UPSLOPE COMPONENT STRENGTHENS. OVER THE WEST...THE STRONGEST LOW LEVEL CONV IS EXPECTED INTO IRONWOOD/WAKEFIELD/BERGLANDWITH SNOWBANDS ORIGINATING NEAR THUNDER BAY. THE GREATEST SNOWFALL AMOUNTS TONIGHT SHOULD ALSO BE IN THE 3 TO 6 INCH RANGE. WITH THE STRONGER UPWARD MOTION IN THE DGZ FOR MUCH OF THE EVENT...SLR VALUES IN THE 20-25/1 RANGE ARE EXPECTED. THERE MAY ALSO BE SOME GUSTY WINDS ALONG THE LAKESHORE TONIGHT WHERE WINDS MAY GUST TO AROUND 30 MPH. ALTHOUGH THE SNOW MAY SLOW TRAVEL AND MAKE ROADS HAZARDOUS BUT OVERALL IMPACTS ARE NOT EXPECTED TO BE SEVERE. SO...GOING LES ADVISORY LEVEL HEADLINES FOR THE NORTHERN CWA IS ON TRACK. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 443 AM EST TUE NOV 26 2013 LK EFFECT COVERAGE AND INTENSITY THROUGH THANKSGIVING IS THE MAIN FORECAST FOCUS. IN THE LARGER SCALE TO START WEDNESDAY...SHORTWAVE TROUGH THAT HELPED TO IGNITE LATEST ROUND OF LAKE EFFECT WILL BE CROSSING LOWER GREAT LAKES. TROUGH EVENTUALLY MEETS UP WITH PAIR OF SHORTWAVES PUSHING OUT OF CNTRL AND SOUTHEAST CONUS TO HELP GIN UP STRONG LOW PRESSURE SYSTEM OVER THE MID ATLANTIC STATES. THAT SYSTEM AND ITS RAIN/SNOW AND WIND IMPACTS WILL BE PRIME FOCUS FOR THE WEATHER ACROSS THE CONUS. BACK ACROSS UPR MICHIGAN...MODERATE LK EFFECT WILL BE ONGOING FOR NORTH FLOW AREAS. THOUGH THERE IS GRADUAL LOWERING OF INVERSIONS THROUGH THE DAY ON WEDNESDAY...NORTH WINDS PERSIST IN THE LAKE CONVECTIVE LAYER AND IT REMAINS PLENTY COLD ENOUGH WITH TEMPS AT INVERSION TOP OF 5-7KFT STAYING IN THAT IDEAL RANGE OF -15C TO -20C. BUFKIT COBB OUTPUT SUGGESTS SLR/S AT IWD AND MQT POINTS NEARING 30:1. CUT THESE SLIGHTLY THOUGH DUE TO SOME FRACTURING OF SNOWFLAKES WITH WINDS AOA 20 KTS BLO CLOUD BASE. LK EFFECT ADVYS IN THE SHORT TERM WILL CARRY THROUGH MIDDAY WEDNESDAY IN THE FAR WEST AND INTO LATE AFTN FOR MARQUETTE COUNTY INTO WESTERN ALGER COUNTY. EXPECT ADDITIONAL DAYTIME SNOW ACCUMS UP TO 5 INCHES...GREATEST FOR THE HIGHER TERRAIN OF WESTERN MARQUETTE COUNTY WITH EXPECTED NNE WINDS BLO 5KFT. AS AFTN WEARS ON...INTENSITY OF SNOW SHOWERS SHOULD START TO RELAX AS H85-H7 MOISTURE THINS OUT AND LOW-LEVEL WINDS BECOME MORE ANTICYLONIC...ESPECIALLY FOR FAR WESTERN CWA. AWAY FM LK EFFECT SHOULD BE GENERALLY CLOUDY DAY AS SOUNDINGS SHOW H85-H8 MOISTURE DUE TO WINDS FLOWING OFF LK SUPERIOR...STAYS TRAPPED BENEATH LARGER SCALE SUBSIDENCE WHICH IS PRETTY TYPICAL FOR THIS TIME OF YEAR GIVEN THE LOW SUN ANGLE. TEMPS WILL BE IN THE 20S ACROSS THE AREA. WEAKENING LOW-LEVEL FLOW ALLOWS MESOSCALE TO BECOME MAIN DRIVER FOR CONVERGENCE/LK EFFECT AREAS ON WEDNESDAY NIGHT. LEANED ON THE NAM AS OUTPUT MADE A LOT OF SENSE WITH EXPECTED SFC PATTERN AND WINDS AT H9 WHICH WILL BE IN THE LAKE CLOUD-BEARING LAYER. AS RETURN FLOW TRIES TO GET GOING AND ALSO DUE TO LAND BREEZE...MESOLOW PROBABLY FORMS BY WED EVENING JUST ALONG SHORE FM SAXON HARBOR TO SILVER CITY. AS H9 WINDS BECOME MORE SW...EXPECT SNOW SHOWERS TO LIFT TOWARD KEWEENAW LATE. MODERATE SNOWS MAY BE ONGOING...BUT IMPACT WOULD BE LIMITED TO FAR WESTERN SHORE OF KEWEENAW PENINSULA. FARTHER EAST...EXPECT SIMILAR SETUP IN THE MARQUETTE AREA. WINDS SLOWLY BACKING NRLY IN THE EVENING LIKELY WILL PUSH SNOW SHOWERS OFF THE HIGHLANDS OF WESTERN MARQUETTE COUNTY AND TOWARD THE LK SUPERIOR SHORE AND INTO EASTERN PORTIONS OF MARQUETTE COUNTY. LAND BREEZE MAY ALLOW FOR DECENT CONVERGENT BAND SOMEWHERE BTWN MARQUETTE/HARVEY AND AU TRAIN. MINIMAL CHANGE IN H925-H85 TEMPS AND INVERSION HEIGHTS ON WEDNESDAY NIGHT WOULD ALLOW FOR AT LEAST MODERATE SNOW ACCUMS WITHIN THIS CONVERGENT AREA. THIS MAY POSE SOME PROBLEM FOR THE ENDING OF THE HEADLINE ON WEDNESDAY AFTN...BUT WILL LET LATER SHIFTS EXTEND THE ADVY IF IT IS NEEDED AS DO NOT KNOW EXACTLY WHERE THE HEAVIER SNOW WOULD END UP. POSSIBLE THAT BAND OF SNOW WILL STILL BE AROUND FOR DAYBREAK ON THANKSGIVING...BUT THINK THAT THE RETURN FLOW OVER THE WEST WILL MAKE ITS WAY EAST AND KICK THE MAIN SNOW SHOWERS OUT ACROSS LK SUPERIOR. SOUNDINGS SHOW INCREASE IN MID-LEVEL MOISTURE LATE WEDNESDAY NIGHT AS ANOTHER SHORTWAVE DROPS ACROSS UPR LAKES IN NW FLOW. SMALL POPS AWAY FM LK EFFECT AREAS LATE IN THE WEST TO ACCOUNT FOR THE SHORTWAVE. SHORTWAVE CROSSES THE AREA ON THANKSGIVING...MAINLY THROUGH MID AFTN. ALSO A BIT OF A WEAK SFC TROUGH TOO. SOUNDINGS SHOW DECENT LIFT OCCURRING FM H9-H7 WHICH IS FIRMLY WHERE THE DGZ RESIDES. EVEN WITH A BIT OF DRY AIR BLO H85...THINK THE LIFT AND MOISTENING FM ABOVE WILL BE ENOUGH TO PRODUCE LGT SNOW OVER MUCH OF THE CWA...EXCEPT MAYBE THE FAR SCNTRL. AMOUNTS WILL BE LESS THAN AN INCH. ONE EXCEPTION TO THAT COULD BE OVER THE KEWEENAW WHERE ONSHORE FLOW/CONVERGENCE COULD BOOST SNOW AMOUNTS ALONG TIP OF THE KEWEENAW. NOT EXPECTING ANY HEADLINE AMOUNTS THOUGH AS WIND FIELDS ARE PRETTY VARIABLE INDICATING SNOW SHOWERS WILL NOT REMAIN IN ANY ONE LOCATION VERY LONG. LATEST RUNS SHOW ENOUGH OF SW PUSH IN AFTN TO ADVECT SNOW SHOWERS OUT OVER NCNTRL LK SUPERIOR. GFS/ECMWF INDICATE LOW PRESSURE TROUGH THAT IS LEFT BEHIND IN WAKE OF SHORTWAVE SHOULD SINK BACK INTO AT LEAST NORTHWEST CWA LATER THURSDAY NIGHT. CHANCE POPS FOR SNOW SHOWERS WERE CARRIED FOR THAT TIME AND INTO FRIDAY AS WELL. EXPECTED N FLOW IN WAKE OF TROUGH ALSO RESULTED IN LOWER CHANCES LINGERING INTO NCNTRL CWA. TROUGH AND ANY LINGERING SNOW SHOWERS DISSIPATE BY FRIDAY EVENING AS PRESSURE GRADIENT REGROUPS AHEAD OF DEVELOPING TROUGH OVR SCNTRL CANADA. SHORTWAVE AND SFC TROUGH STAY MAINLY TO THE NORTH OF UPR LAKES FOR THE UPCOMING WEEKEND. BEST SHOT OF LGT SNOW WILL BE OVR LK SUPERIOR ON SATURDAY CLOSER TO THE SHORTWAVE/Q-VECTOR CONVERGENCE AND MORE SATURATED LOW-LEVELS. A LOT OF CLOUD COVER OVER REST OF CWA ALONG WITH BREEZY SOUTH WIND THAT WILL BRING A RETURN OF SLIGHTLY ABOVE FREEZING TEMPS OVER MUCH OF CWA. RAN WITH CONSENSUS BEYOND SATURDAY WITH DIFFERENCES SHOWING UP IN HOW QUICK TO BRING NEXT SHORTWAVE AND SFC TROUGH/PRECIP INTO UPR LAKES. DOES LOOK LIKE TEMPS WILL STAY RELATIVELY WARMER /HIGHS IN THE 30S COMPARED TO TEENS OR 20S/ BEFORE ANOTHER PUSH OF COLDER AIR ARRIVES JUST BEYOND THE SCOPE OF THE LONG TERM TIME RANGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1242 PM EST TUE NOV 26 2013 KCMX...EXPECT IFR CONDITIONS THROUGH MUCH OF THE PERIOD IN LAKE EFFECT SNOW AND SOME BLOWING OF SNOW DUE TO WINDS GUSTING NEAR 25 MPH. WINDS WILL SHIFT FROM NW TO N LATER THIS EVENING CONTINUING INTO WEDNESDAY. KIWD...EXPECT MVFR CONDITIONS TO OCCASIONAL IFR CONDITIONS TODAY IN NW FLOW LAKE EFFECT. CONDITIONS WILL DETERIORATE TO LIFR LATER THIS EVENING AS WINDS SHIFT NORTHERLY AND LAKE EFFECT SNOW INCREASES. KSAW....MVFR CONDITIONS IN SCT LAKE EFFECT SNOW WILL DETERIORATE TO IFR AND PERHAPS EVEN OCCASIONALLY LIFR LATE TONIGHT INTO WEDNESDAY AS WINDS SHIFT FROM NW TO N AS LAKE EFFECT SNOW INCREASES IN INTENSITY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST TUE NOV 26 2013 NW WINDS TO 30 KTS TODAY AS WE ARE IN THE WAKE OF COLD FRONT THAT MOVED THROUGH MONDAY EVENING. ANOTHER TROUGH DROPS SOUTH ACROSS LK SUPERIOR LATE TODAY AND THIS EVENING RESULTING IN WINDS SHIFTING TO NORTH OR NORTHEAST. GALES LOOK LIKELY OVER MAINLY EAST HALF SO GALE WARNING HAS BEEN POSTED. GALES LINGER INTO WEDNESDAY BEFORE WINDS QUICKLY DIMINISH TO LESS THAN 20 KTS AS WEAK PRESSURE GRADIENT DEVELOPS FOR THANKSGIVING. WINDS STAY LIGHT UNTIL SATURDAY WHEN SOUTH WINDS INCREASE AHEAD OF LOW PRESSURE SYSTEM CROSSING SCNTRL CANADA. WINDS MAY REACH 30 KTS OVER EASTERN SECTIONS INTO SATURDAY EVENING. MORE LIGHT WINDS TO END THE WEEKEND AS PRESSURE GRADIENT RELAXES AGAIN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 3 PM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL NOON EST /11 AM CST/ WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001- 003. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY UNTIL 3 PM EST WEDNESDAY FOR MIZ006. LAKE SUPERIOR... GALE WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR LSZ266-267. GALE WARNING FROM 1 AM TO 10 AM EST WEDNESDAY FOR LSZ265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...VOSS MARINE...JLA
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1215 PM CST TUE NOV 26 2013 .DISCUSSION... 18Z AVIATION DISCUSSION. && .AVIATION... INTERESTING FORECAST THIS MORNING AS A COLD UPPER LOW DIGS DOWN OVER THE EASTERN TEXAS/COASTAL BEND THROUGH THE DAY. THE ATMOSPHERIC COLUMN BEGINS TO DRY THROUGH LATE AFTERNOON/EARLY EVENING...BUT THAT WINDOW BETWEEN WHERE THERE IS JUST ENOUGH MOISTURE (OR ICE CRYSTAL NUCLEI) IN TANDEM WITHIN ANY SUB-FREEZING LAYER OF ANY SIGNIFICANT THICKNESS...WILL BE THE DETERMINING FACTOR AS TO WHETHER NORTHERN HUB RECEIVE A RAIN-SNOW MIXTURE THROUGH THE EARLY AFTERNOON. AS OF NOW...THE THERMODYNAMIC NATURE OF THE PROGGED PROFILES OVER THE FAR NORTHERN HUBS COULD SUPPORT THIS SCENARIO AS THE UPPER LOW PASSES BY. THE BEST CHANCE FOR ANY FROZEN PRECIPITATION FOR SUCH HUBS AS KUTS OR KCXO WILL BE BY LATE AFTERNOON AND WOULD BE IN MIXED FORM...LIGHT RAIN OR DRIZZLE WITH EITHER SNOW OR ICE PELLETS. THIS COULD TEMPORARILY TURN OVER TO ALL SNOW OVER THE EXTREME NORTHERN TERMINALS (KUTS). A LOW FREEZING LINE...AND A FAIRLY-SATURATED BELOW FREEZING COLUMN UP THROUGH THE UPPER ATMOSPHERE DUE TO WRAP-AROUND MOISTURE...MAKES FOR A HIGHER POTENTIAL FOR AIRCRAFT ICE RIMING THROUGH THIS EVENING. AS THE UPPER LOW EXITS EAST...DECKS WILL GRADUALLY LIFT TO MVFR THROUGH EARLY EVENING TO MAINLY SKY CLEAR/SCT250 BY MIDNIGHT. A VERY TIGHT OFFSHORE PRESSURE GRADIENT WILL MAKE FOR MODERATE NORTHWESTERN INTERIOR WINDS...STRONG ALONG THE IMMEDIATE COAST THROUGH THE PERIOD. 31 && .PREV DISCUSSION... /ISSUED 1006 AM CST TUE NOV 26 2013/ UPDATE... SEE MORNING UPDATE. DISCUSSION... 12Z DATA SHOWS THE UPPER LEVEL TROUGH AXIS STILL TO THE WEST WITH SOME WEAK DIVERGENCE NOTED OVER EAST TEXAS. MOISTURE STILL LOOKS RATHER PLENTIFUL AT 850 AND 700 MB. THE FREEZING LINE AT 850 MB EXTENDS ACROSS THE WESTERN HALF OF SE TX. SHORT TERM GUIDANCE SUGGESTS THAT MSTR WILL LINGER A BIT LONGER THAN EXPECTED YESTERDAY AND FORCING FROM THE UPPER TROUGH SHOULD CONTINUE TO FOSTER PERIODS OF LIGHT RAIN THROUGH EARLY AFTN. WILL BUMP POPS TO HIGH END CHANCE FOR THE EASTERN HALF OF THE CWA. RAP AND 12Z NAM 12 SOUNDINGS SUGGEST SOME POTENTIAL FOR WINTER PRECIP OVER THE NE QUARTER OF THE CWA. SOUNDINGS LOOK COLD ENOUGH FOR SNOW AROUND 18Z FROM CROCKETT TO LIVINGSTON. NOT SURE HOW COLD MID LEVEL AIR WILL BE BUT ADDED A RAIN/SNOW MIX FOR THE NE PART OF THE AREA. SURFACE TEMPS WILL REMAIN TOO WARM FOR ANYTHING TO ACCUMULATE. NEW ZONES OUT BY 1030 AM. 43 && PREV DISCUSSION... /ISSUED 434 AM CST TUE NOV 26 2013/ DISCUSSION... THE LARGE AREA OF PRECIPITATION THAT HAS LINGERED ACROSS SOUTHEAST TEXAS SINCE EARLY MONDAY IS BEGINNING TO SHIFT OFF TO THE EAST WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THIS SYSTEM IS DIGGING SOUTHWARD ACROSS THE SOUTH PLAINS AND APPROACHING THE HILL COUNTRY THIS MORNING. OF GREATEST CONCERN THIS MORNING IS THE POTENTIAL FOR SOME WINTRY PRECIPITATION TO MIX IN WITH THE RAIN AS THE LOW BRINGS COOLER TEMPERATURES ALOFT INTO THE REGION. A 09Z SOUNDING FROM COLLEGE STATION SHOWS A WARM NOSE AT 800MB WITH A WARM LAYER OF APPROXIMATELY 3KFT. BELOW THIS LAYER TEMPERATURES FALL BACK BELOW FREEZING FOR 3KFT BEFORE RISING ABOVE FREEZING AGAIN IN THE LAST 800 FEET. THIS SUPPORTS THE CURRENT FORECAST REASONING WHICH IS FOR RAIN WITH SOME SLIGHT CHANCE FOR SLEET MIXED IN ALONG AND NORTH OF A LINE FROM CALDWELL TO LIVINGSTON. WITH SURFACE TEMPERATURES IN THE UPPER 30S NO ACCUMULATION IS EXPECTED ACROSS THIS AREA. FURTHER SOUTH...PRECIPITATION WILL REMAIN AS RAIN. AS THE MAIN UPPER LOW APPROACHES WE COULD BRIEFLY SEE THE POTENTIAL FOR A FEW SNOW FLURRIES TO MIX IN WITH THE RAIN AS TEMPERATURES ALOFT BEGIN TO COOL...BUT THIS IS NOT LIKELY TO OCCUR BEFORE THE MOISTURE SHIFTS OFF TO OUR EAST AND PRECIPITATION ENDS ACROSS THE REGION. THE UPPER LOW WILL CROSS THE REGION TODAY BRINGING DRIER AND COOLER AIR IN ITS WAKE. UNSEASONABLY COLD TEMPERATURES ARE EXPECTED WEDNESDAY AND THURSDAY MORNINGS WITH A LIGHT FREEZE EXPECTED ACROSS THE NORTHERN HALF OF THE REGION. A SLOW WARMING TREND WILL BEGIN LATE IN THE WEEK THROUGH THE WEEKEND AS HIGH PRESSURE EXITS THE REGION AND ONSHORE FLOW RESUMES. NEXT CHANCE FOR RAIN WILL BE LATE THIS WEEKEND AS A WEAK DISTURBANCE MOVES ACROSS THE REGION. 38 && MARINE... STRONG NORTH TO NORTHWEST WINDS AND ROUGH SEAS WILL CONTINUE THROUGH TONIGHT AS AN INTENSE UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH THE UPPER TEXAS COASTAL WATERS. SMALL CRAFT ADVISORIES REMAIN IN EFFECT...AND WIND GUSTS TO GALE FORCE WILL BE POSSIBLE. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA...WINDS TURN TO THE NORTHEAST...AND SEAS COME DOWN. LIGHT TO MODERATE NORTHEAST TO EAST WINDS ARE ANTICIPATED BEGINNING ON THURSDAY AND CONTINUING INTO EARLY SATURDAY. A STRENGTHENING ONSHORE FLOW IS IN THE FORECAST FOR THE END OF THE WEEKEND. 42 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 30 48 29 54 35 / 10 0 0 0 0 HOUSTON (IAH) 32 51 30 57 37 / 10 0 0 0 0 GALVESTON (GLS) 42 50 42 57 50 / 10 0 0 0 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...JACKSON... MATAGORDA. GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...43 AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1006 AM CST TUE NOV 26 2013 .UPDATE... SEE MORNING UPDATE. && .DISCUSSION... 12Z DATA SHOWS THE UPPER LEVEL TROUGH AXIS STILL TO THE WEST WITH SOME WEAK DIVERGENCE NOTED OVER EAST TEXAS. MOISTURE STILL LOOKS RATHER PLENTIFUL AT 850 AND 700 MB. THE FREEZING LINE AT 850 MB EXTENDS ACROSS THE WESTERN HALF OF SE TX. SHORT TERM GUIDANCE SUGGESTS THAT MSTR WILL LINGER A BIT LONGER THAN EXPECTED YESTERDAY AND FORCING FROM THE UPPER TROUGH SHOULD CONTINUE TO FOSTER PERIODS OF LIGHT RAIN THROUGH EARLY AFTN. WILL BUMP POPS TO HIGH END CHANCE FOR THE EASTERN HALF OF THE CWA. RAP AND 12Z NAM 12 SOUNDINGS SUGGEST SOME POTENTIAL FOR WINTER PRECIP OVER THE NE QUARTER OF THE CWA. SOUNDINGS LOOK COLD ENOUGH FOR SNOW AROUND 18Z FROM CROCKETT TO LIVINGSTON. NOT SURE HOW COLD MID LEVEL AIR WILL BE BUT ADDED A RAIN/SNOW MIX FOR THE NE PART OF THE AREA. SURFACE TEMPS WILL REMAIN TOO WARM FOR ANYTHING TO ACCUMULATE. NEW ZONES OUT BY 1030 AM. 43 && .PREV DISCUSSION... /ISSUED 555 AM CST TUE NOV 26 2013/ AVIATION... CURRENT BATCH OF -RA/RA WILL BE EAST OF OUR TAF SITES BY AROUND 14Z. AS THE UPPER LOW CENTER MOVES ACROSS THE AREA LATER THIS MORNING THROUGH THIS AFTERNOON...SOME HIGH RES MODELS ARE INDICATING POSSIBLE ADDITIONAL DEVELOPMENT...ESPECIALLY BETWEEN IAH AND GLS. WILL COVER THIS CHANCE WITH TEMPO FOR IAH AND PREVAILING FURTHER TO THE SOUTH. MVFR/IFR CEILINGS THIS MORNING WILL BEGIN TO LIFT LATER THIS AFTERNOON WITH VFR CONDITIONS ANTICIPATED THIS EVENING. WINDS WILL REMAIN ELEVATED FOR MUCH OF THE DAY...ESPECIALLY NEAR THE COAST...THEN COME DOWN THIS EVENING UNDER A RELAXING PRESSURE GRADIENT. 42 PREV DISCUSSION... /ISSUED 434 AM CST TUE NOV 26 2013/ DISCUSSION... THE LARGE AREA OF PRECIPITATION THAT HAS LINGERED ACROSS SOUTHEAST TEXAS SINCE EARLY MONDAY IS BEGINNING TO SHIFT OFF TO THE EAST WITH THE APPROACH OF THE MAIN UPPER LEVEL LOW. THIS SYSTEM IS DIGGING SOUTHWARD ACROSS THE SOUTH PLAINS AND APPROACHING THE HILL COUNTRY THIS MORNING. OF GREATEST CONCERN THIS MORNING IS THE POTENTIAL FOR SOME WINTRY PRECIPITATION TO MIX IN WITH THE RAIN AS THE LOW BRINGS COOLER TEMPERATURES ALOFT INTO THE REGION. A 09Z SOUNDING FROM COLLEGE STATION SHOWS A WARM NOSE AT 800MB WITH A WARM LAYER OF APPROXIMATELY 3KFT. BELOW THIS LAYER TEMPERATURES FALL BACK BELOW FREEZING FOR 3KFT BEFORE RISING ABOVE FREEZING AGAIN IN THE LAST 800 FEET. THIS SUPPORTS THE CURRENT FORECAST REASONING WHICH IS FOR RAIN WITH SOME SLIGHT CHANCE FOR SLEET MIXED IN ALONG AND NORTH OF A LINE FROM CALDWELL TO LIVINGSTON. WITH SURFACE TEMPERATURES IN THE UPPER 30S NO ACCUMULATION IS EXPECTED ACROSS THIS AREA. FURTHER SOUTH...PRECIPITATION WILL REMAIN AS RAIN. AS THE MAIN UPPER LOW APPROACHES WE COULD BRIEFLY SEE THE POTENTIAL FOR A FEW SNOW FLURRIES TO MIX IN WITH THE RAIN AS TEMPERATURES ALOFT BEGIN TO COOL...BUT THIS IS NOT LIKELY TO OCCUR BEFORE THE MOISTURE SHIFTS OFF TO OUR EAST AND PRECIPITATION ENDS ACROSS THE REGION. THE UPPER LOW WILL CROSS THE REGION TODAY BRINGING DRIER AND COOLER AIR IN ITS WAKE. UNSEASONABLY COLD TEMPERATURES ARE EXPECTED WEDNESDAY AND THURSDAY MORNINGS WITH A LIGHT FREEZE EXPECTED ACROSS THE NORTHERN HALF OF THE REGION. A SLOW WARMING TREND WILL BEGIN LATE IN THE WEEK THROUGH THE WEEKEND AS HIGH PRESSURE EXITS THE REGION AND ONSHORE FLOW RESUMES. NEXT CHANCE FOR RAIN WILL BE LATE THIS WEEKEND AS A WEAK DISTURBANCE MOVES ACROSS THE REGION. 38 MARINE... STRONG NORTH TO NORTHWEST WINDS AND ROUGH SEAS WILL CONTINUE THROUGH TONIGHT AS AN INTENSE UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH THE UPPER TEXAS COASTAL WATERS. SMALL CRAFT ADVISORIES REMAIN IN EFFECT...AND WIND GUSTS TO GALE FORCE WILL BE POSSIBLE. CONDITIONS WILL BEGIN TO IMPROVE ON WEDNESDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA...WINDS TURN TO THE NORTHEAST...AND SEAS COME DOWN. LIGHT TO MODERATE NORTHEAST TO EAST WINDS ARE ANTICIPATED BEGINNING ON THURSDAY AND CONTINUING INTO EARLY SATURDAY. A STRENGTHENING ONSHORE FLOW IS IN THE FORECAST FOR THE END OF THE WEEKEND. 42 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 43 30 48 29 54 / 20 10 0 0 0 HOUSTON (IAH) 43 32 51 30 57 / 50 10 0 0 0 GALVESTON (GLS) 46 42 50 42 57 / 50 10 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...JACKSON... MATAGORDA. GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST WEDNESDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...43