Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/13/15


AREA FORECAST DISCUSSION
NWS TAUNTON MA
1018 AM EST WED FEB 11 2015 .SYNOPSIS... GENERALLY COLD AND DRY CONDITIONS EXPECTED TODAY. LIGHT OCEAN EFFECT SNOW WILL AFFECT PORTIONS OF SOUTHEAST COASTAL MASSACHUSETTS TODAY INTO TONIGHT. NUISANCE LIGHT SNOW MAINLY FOR SOUTHEAST NEW ENGLAND ESPECIALLY CAPE COD AND THE ISLANDS THURSDAY INTO FRIDAY. A MORE POTENT WINTER STORM IS POSSIBLE FOR SATURDAY INTO SUNDAY. BELOW AVERAGE TEMPERATURES FOR MUCH OF THE FORECAST PERIOD...WITH AN ARCTIC CHILL EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE... OCEAN EFFECT SNOW FAIRLY EXPANSIVE ACROSS MUCH OF E MA AND INTO RI THIS MORNING. HRRR NOT PICKING UP ON THIS AT ALL BUT HIRESWRF IS HINTING AT IT ALTHOUGH NOT TO THE EXTENT OF WHAT/S HAPPENING. SNOW PRODUCTION ALL OCCURRING BELOW 9O0 MB AS STRONG SUBSIDENCE INVERSION ABOVE THIS. SOUNDINGS ARE SATURATED BELOW 900 MB WITH FAIRLY STEEP LAPSE RATES. COLDEST TEMPS IN THE MIXED LAYER AROUND -11 TO -12C SO DELTA T FROM SST IS RUNNING ABOUT 14-15C AND SATURATION THROUGH -12C ALLOWING FOR ICE NUCLEATION AND FAVORABLE SNOW PRODUCTION. WITH NE TRAJECTORY SNOW IS EXTENDING WEST ACROSS MUCH OF E MA AND EVEN INTO RI. ALSO NOTING SOME DECENT LOW LEVEL CONVERGENCE E COASTAL MA WITH N/NW WINDS AT BOS/OWD AND NE WINDS AT BOS BUOY AND GHG WHICH IS HELPING TO ENHANCE THE SNOW IN THIS AREA. NOT MUCH CHANGE NOTED IN THE SOUNDINGS THROUGH THE DAY SO EXPECT SNOW...MOSTLY LIGHT TO CONTINUE FOR MUCH OF THE DAY IN E MA WITH PERIODIC LIGHTER SNOW IN RI. HIRESWRF MORE BULLISH ON SNOWFALL THIS AFTERNOON ACROSS SE MA COASTAL MA. ACCUM OF AN INCH OR 2 IS LIKELY...ESPECIALLY IN E MA FROM BOS SOUTH THROUGH OWD AND INTO PLYMOUTH COUNTY. FURTHER WEST...EXPECT PT-MOSUNNY SKIES ACROSS CENTRAL AND W MA INTO THE CT VALLEY FURTHER REMOVED FROM MARINE INFLUENCE AND OCEAN MOISTURE. GUSTY N/NE WINDS TO 30-40 MPH WILL CONTINUE INTO THE EARLY AFTERNOON ACROSS SE COASTAL MA AND ESPECIALLY THE CAPE/ISLANDS...STRONGEST AT ACK. WINDS WILL BEGIN TO DIMINISH AFT 18Z. NO CHANGES TO TEMPS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... FOR TONIGHT...SNOW BANDS SHOULD BEGIN TO DISSIPATE BY AROUND MIDNIGHT AS THE LOW DEPARTS AND PRES GRADIENT WEAKENS. NEXT SYSTEM ALREADY STARTS TO APPROACH OUT OF NY STATE. WILL SEE MID AND HIGH CLOUDS INCREASE FROM THE W ACROSS WESTERN AREAS TONIGHT. MAY SEE SOME SCT LIGHT SNOW MOVE INTO THE E SLOPES OF THE BERKSHIRES AFTER 08Z. WINDS WILL BECOME LIGHT AND VARIABLE AS TEMPS FALL BACK... GENERALLY IN THE SINGLE DIGITS AWAY FROM THE COAST EXCEPT POSSIBLY BELOW ZERO IN A FEW SPOTS ACROSS THE HIGHER INLAND TERRAIN... RANGING TO THE TEENS TO LOWER 20S ALONG THE IMMEDIATE COAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... */ HIGHLIGHTS... - NUISANCE LIGHT SNOW THURSDAY INTO FRIDAY - MORE POTENT WINTER STORM POSSIBLE SATURDAY INTO SUNDAY - ARCTIC CHILL EARLY NEXT WEEK */ OVERVIEW... DETERMINISTIC AND ENSEMBLE-MEMBER SOLUTIONS CLUSTERING QUITE WELL FOR THE THURSDAY-FRIDAY PERIOD WITH THE NUISANCE LIGHT SNOW MAINLY ACROSS SE NEW ENGLAND FOLLOWING BY AN ARCTIC INTRUSION OF COLDER AIR. THEREAFTER ENSEMBLE SOLUTIONS ARE PREFERRED WHICH ADVERTISE A +PNA/+NAO TREND. LOOKING AT AN ACTIVE WEATHER PATTERN LONG TERM WITH PREFERRED TROUGHING ACROSS THE E-CONUS ALONG WITH CONTINUED WAVES OF ARCTIC AIR. WINTER NOT COMING TO AN END ANY TIME SOON. TEMPERATURES EXPECTED TO REMAIN BELOW-NORMAL FOR QUITE SOMETIME. NO CONFIDENCE TO ASSUME THIS PATTERN WILL BREAK ANY TIME SOON. */ DAILIES... THURSDAY INTO FRIDAY MORNING... FORECAST GUIDANCE CONSENSUS SIGNALS A PROGRESSIVE FLOW PATTERN THRU WHICH PACIFIC-ENERGY DIVES SE THRU BROADER CYCLONIC FLOW AMPLIFYING AN H5 OPEN-WAVE TROUGH AND ACCOMPANYING JET-STREAK ACROSS THE NE- CONUS. SURFACE LOW PRESSURE IS INVOKED ACROSS REGIONS OF BETTER BARO- CLINICITY WELL-OFFSHORE OF NEW ENGLAND SE OF THE 40N/70W BENCHMARK TUESDAY QUICKLY DEEPENING EASTWARD TOWARDS SE CANADA TUESDAY NIGHT. AM SKEPTICAL AS TO WHETHER WE WILL EVEN SEEN ADVISORY-LEVEL CRITERIA WITH THIS STORM. VENTURE TO GUESS THAT REACHING CRITERIA WOULD BE A CONSEQUENCE OF THE FLUFF-FACTOR OF THE SNOW WITH HIGH SNOW-TO- LIQUID RATIOS.INTENSIFICATION/OCCLUSION OF THE STORM DOES NOT OCCUR UNTIL WELL DOWNSTREAM BY WHICH POINT THE H7 LOW CLOSES OFF AS WARM- MOIST HIGHER-PWAT AIR IS DRAWN INTO THE CENTER. MUCH OF THE FOCUS ACROSS OUR REGION IS DURING THE OVERRUNNING PHASE ALBEIT BRIEF AS LOW- TO MID-LEVEL MOISTURE ISENTROPICALLY ASCENDS ALONG 285-295K SURFACES ENCOUNTERING FRONTOGENESIS ALONG THE SW-NE THERMAL GRADIENT AND MID-LEVEL ASCENT PER MAIN IMPULSE THROUGH THE H5 OPEN-WAVE TROUGH. NO LONGER DOES IT APPEAR THAT TROWALING AND BACK-BANDING OF MOISTURE WILL PREVAIL AS THE STORM WILL BE WELL DOWNSTREAM. LOOKING AT LIGHT SNOW TO RAMP-UP THROUGH THE DAY THURSDAY...WITH THE MAJORITY OF IMPACTS CENTERED AROUND THE THURSDAY AFTERNOON/ EVENING COMMUTE WHEN ISENTROPIC ASCENT/DEEP-LAYER LIFT ARE AT THEIR GREATEST POTENTIAL YIELDING DECENT OMEGA THRU BEST SNOW- GROWTH REGIONS. AM EXPECTING ACTIVITY TO TAPER OFF BEGINNING MIDNIGHT INTO FRIDAY MORN. NOT A PRONOUNCED SYSTEM...BUT THE LONGEVITY OF WHICH LOOK TO YIELD QPF AMOUNTS AROUND 0.2 INCHES... AND CONSIDERING A 12:1 TO 15:1 SNOW TO LIQUID RATIO WOULD RESULT IN SNOWFALL AMOUNTS RANGING ON AVERAGE 2 TO 4 INCHES. SO THIS EVENT IS APPEARING TO BE A LOW-END ADVISORY STORM /WHEW/ FOR MAINLY THE CAPE AND ISLANDS BASED ON CONFIDENCE. BUT AM GOING TO HOLD OFF ON THE ISSUANCE OF ANY HEADLINES. WHY? WELL FOR ONE FORECAST GUIDANCE HAVE TRENDED SLIGHT FASTER AND E WITH THIS SYSTEM...AND TWO...THIS HAS SUBSEQUENTLY DOWNGRADED QPF AMOUNTS. AM GOING TO LET THE DAY- SHIFT TAKE ONE MORE LOOK AT IT BUT AGAIN BASED ON CONFIDENCE...WOULD SUGGEST WINTER WEATHER ADVISORIES FOR THE CAPE AND ISLANDS. AS THE STORM LIFTS OUT TO SEA INTENSIFYING...ISALLOBARIC COMPONENT OF THE WIND AMPLIFIES THE NW-FLOW. COUPLED WITH STRONG COLD-AIR ADVECTION REARWARD...AND WIND CHILLS ARE EXPECTED TO FALL TO OR BELOW -15 DEGREES ACROSS THE HIGH TERRAIN OF THE BERKSHIRES AND WORCESTER HILLS. FRIDAY INTO SATURDAY MORNING... FRIDAY WILL BE WINDY OUT OF THE NW AS THE STORM AMPLIFIES TO THE E AND HIGH PRESSURE BUILDS IN FROM THE W. A COLD DAY FOR SURE AIDED BY BLUSTERY FLOW MAKING IT FEEL COLDER. MID- TO UPPER-20S HIGHS WILL ACTUALLY FEEL MORE IN THE TEENS. MUCH COLDER INTO SATURDAY MORNING AS HIGH PRESSURE ALLOWS WINDS TO RELAX OVER THE DEEP SNOWPACK. A SAVING CAVEAT PREVENTING GOOD RADIATIONAL COOLING IS INCREASING CLOUDS AHEAD OF THE NEXT STORM SYSTEM THROUGH THE REMAINDER OF THE WEEKEND. LOWS FALLING INTO THE SINGLE DIGITS WITH A FEW SPOTS LIKELY TO FALL BELOW-ZERO...ESPECIALLY E/NE INTERIOR MASSACHUSETTS. WIND CHILL ADVISORIES MAY NEED TO CONTINUE THROUGH THE DAY FOR THE HIGH TERRAIN OF N/W MA...DEFINITELY FRIDAY NIGHT INTO SATURDAY MORN. SATURDAY INTO SUNDAY... CONTINUED ENSEMBLE/DETERMINISTIC AGREEMENT OF AN ARCTIC IMPULSE DIVING SE THRU THE BROADER CYCLONIC FLOW INVOKING A CLOSED H5 LOW AND SURFACE LOW PRESSURE REFLECTION IN PROXIMITY TO THE 40N/70W BENCHMARK AROUND MIDNIGHT SUNDAY. WHILE THE THURSDAY-FRIDAY SYSTEM LOOKS MEDIOCRE...THE SATURDAY-SUNDAY SYSTEMS APPEARS TO HAVE MORE POTENCY AND A MORE PLOWABLE SNOW. ASSOCIATED ENERGY IS STILL WELL N OVER THE ARCTIC...POORLY SAMPLED. BUT THAT DOES NOT DETER FROM EVALUATING. AS HAS BEEN THE PATTERN WITH ROBUST SYSTEMS THIS SEASON...AN INITIAL OVER-RUNNING EVENT TRANSITIONS INTO MORE MESOSCALE BANDING REARWARD OF THE SYSTEM WITHIN BETTER LOW- TO MID-LEVEL TROWALING / FRONTOGENESIS AS THE LOW INTENSIFIES DRAWING WARM-MOIST AIR CYCLONICALLY TO ITS CORE. SIMILAR SIGNALS APPEAR WITH THIS SYSTEM WITH THE MAJORITY OF IMPACTS ACROSS SE NEW ENGLAND. SOLUTIONS WOBBLE AND ARE SLIGHTLY PROGRESSIVE WITH AN INCREASINGLY POSITIVE-FORECAST NAO SIGNAL. QUESTION AS TO WHETHER OUTCOMES ARE COMPLICATED BY THE NON-CLASSIC DOUBLE-BARREL H5 LOW PATTERN FORECAST ACROSS THE NE- CONUS. STILL PLENTY OF TIME TO CHEW ON THIS ONE. SHOULD PROBABLY GET THROUGH THE THURSDAY-FRIDAY STORM FIRST. SUNDAY NIGHT INTO EARLY NEXT WEEK... AS HAS BEEN THE CASE OVER THE PAST WEEK...DETERMINISTIC/ENSEMBLE- MEMBER SOLUTIONS HAVE SIGNALED A DECENT ARCTIC AIR OUTBREAK TOWARDS MID-FEBRUARY. CIPS ANALOGS CONTINUE TO CONVEY HIGH CONFIDENCE ALONG WITH THE FORECAST CONSENSUS AVERAGE OF H85 TEMPS FALLING BELOW -20C FOR THE PERIOD RESULTING IN HIGHS ONLY INTO THE TEENS WITH LOWS WELL BELOW-ZERO INTO MONDAY. A BELOW-NORMAL PATTERN CONTINUING FOR THE REST OF THE EARLY WEEK PERIOD LOCKED IN BY HIGH PRESSURE. WIND-CHILL HEADLINES WILL LIKELY NEED TO BE ENTERTAINED FOR THE SATURDAY NIGHT INTO MONDAY MORNING TIMEFRAME. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. 15Z UPDATE... TODAY...HIGH CONFIDENCE. INTERIOR VFR WITH AREAS OF MVFR/IFR IN OCEAN EFFECT SNOW E MA. MVFR CONDITIONS EXTENDING INTO RI. LIGHT ACCUMS UPWARDS OF 2 INCHES IN SPOTS...GENERALLY AROUND 1-INCH. NE WIND GUSTS TO 25-35 KT SE COASTAL MA AND CAPE/ISLANDS WILL BEGIN TO DIMINISH AFT 18Z. TONIGHT...HIGH CONFIDENCE. MVFR E MA/RI WITH -SN LINGERING. CONTINUED MVFR-IFR VSBYS WITH -SN TOWARDS 6Z. VFR W WITH INCREASING MID-HIGH CIGS. N/NE-WINDS DIMINISH GUSTING UPWARDS AROUND 25 KTS. KBOS TAF...MODERATE CONFIDENCE IN TAF. MVFR VSBYS POSSIBLE WITH -SN. HELD WITH -6SM. PRESENT N/NW-WINDS ARE EXPECTED TO KEEP THE MORE MODERATE SNOW S OF THE TERMINAL. KBDL TAF...HIGH CONFIDENCE IN TAF. WILL HOLD VFR THROUGHOUT. OUTLOOK...THURSDAY THROUGH SUNDAY... THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. MAJORITY OF IMPACTS OVER SE NEW ENGLAND ESP CAPE COD / ISLANDS. -SN. MVFR-LIFR IMPACTS. INCREASING NW-WINDS INTO FRIDAY...TAPERING LATE. GUSTS 25-30 KTS... STRONGER ACROSS THE COAST UP AROUND 35 KTS. FRIDAY NIGHT INTO EARLY SATURDAY...MODERATE CONFIDENCE. VFR. NW-WINDS DIMINISHING. BRIEF PERIOD OF SKC PRIOR TO INCREASING MID- TO HIGH-LEVEL CIGS LATE. SATURDAY INTO SUNDAY...LOW CONFIDENCE. ANOTHER STORM SYSTEM. FOCUS OF IMPACTS ACROSS E/SE NEW ENGLAND. MVFR-LIFR IMPACTS WITH SNOW. LLWS IMPACTS POSSIBLE DURING ONSET WITH N/NE WINDS AT THE SURFACE AND BREEZY SW-WINDS 2 KFT AGL ALOFT. OTHERWISE RETURN OF BLUSTERY NW-WINDS IN WAKE OF THE STORM. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...HIGH CONFIDENCE. 7 AM UPDATE...NO MAJOR CHANGES. NE WINDS WILL CONTINUE TO GUST TO 35-40 KT ON THE SOUTHERN WATERS THIS MORNING...BUT SHOULD START TO DIMINISH TO SMALL CRAFTS BEGINNING AROUND MIDDAY ON THE NEAR SHORE BAYS/SOUNDS. CONTINUES SMALL CRAFTS THROUGH TONIGHT. WINDS WILL DIMINISH TONIGHT AS LOW PRES WELL S OF NEW ENGLAND MOVES AWAY AND HIGH PRES RIDGE BUILDS ACROSS. HOWEVER...SEAS WILL REMAIN HIGH FROM LEFTOVER SWELLS FROM THE LOW. LIGHT FREEZING SPRAY EXPECTED THROUGH THIS EVENING. OUTLOOK...THURSDAY THROUGH SUNDAY... THURSDAY INTO FRIDAY...MODERATE CONFIDENCE. MAJORITY OF IMPACTS OVER SE NEW ENGLAND ESP CAPE COD / ISLANDS. LIGHT SNOW. VISIBILITY IMPACTS OVER THE WATERS. INCREASING NW- WINDS INTO FRIDAY WITH GALE FORCE GUSTS AND WAVES BUILDING 8 TO 10 FEET ON THE OUTER WATERS...BOTH OF WHICH TAPERING LATE FRIDAY. FRIDAY NIGHT INTO EARLY SATURDAY...MODERATE CONFIDENCE. NW-WINDS DIMINISHING VEERING W. HIGH PRESSURE BUILDING INTO THE WATERS. SEAS DROPPING BELOW 5 FEET BY SATURDAY MORNING. SATURDAY INTO SUNDAY...LOW CONFIDENCE. ANOTHER STORM SYSTEM. FOCUS OF IMPACTS ACROSS E/SE NEW ENGLAND. SNOW ANTICIPATED RESULTING IN VISIBILITY RESTRICTIONS OVER THE WATERS. OTHERWISE RETURN OF BLUSTERY NW-WINDS IN WAKE OF THE STORM TO GALE FORCE BEGINNING SUNDAY MIDNIGHT. POTENTIAL FOR GUSTS UP TO AROUND 45 KTS SUNDAY. SEAS POTENTIALLY BUILDING UP TO 20 FEET ON THE OUTER WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR ANZ232-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ233>235-237. SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ230. SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR ANZ231. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ236. SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ250-251. GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR ANZ254-255. && $$ SYNOPSIS...SIPPRELL/EVT NEAR TERM...KJC SHORT TERM...EVT LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL/EVT MARINE...SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1012 AM EST WED FEB 11 2015 .SYNOPSIS... A HIGH PRESSURE SYSTEM OVER SOUTHERN QUEBEC PROVINCE WILL SLOWLY EASE EAST TODAY AND TONIGHT. A COLD FRONT WILL CROSS THE AREA ON THURSDAY, WITH A STRONG LOW PRESSURE SYSTEM DEVELOPING ALONG THIS FRONT AND INTENSIFYING RAPIDLY AS IT MOVES SOUTHEAST OF CAPE COD. AN ARCTIC HIGH PRESSURE SYSTEM WILL MOVE OVER THE REGION ON FRIDAY. ANOTHER LOW PRESSURE SYSTEM MOVING THROUGH THE EASTERN GREAT LAKES ON SATURDAY IS PREDICTED TO INTENSIFY EVEN MORE RAPIDLY AS IT PASSES SOUTH OF LONG ISLAND ON SATURDAY NIGHT. ANOTHER ARCTIC HIGH PRESSURE SYSTEM SHOULD THEN REACH THE MISSISSIPPI VALLEY ON SUNDAY AND THE APPALACHIANS ON MONDAY. A LOW PRESSURE SYSTEM SHOULD REACH THE TENNESSEE VALLEY ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN AREA OF LOW PRESSURE THAT WAS LOCATED ABOUT 500 MILES OFF THE MID-ATLANTIC COAST THIS MORNING WILL CONTINUE TO DRIFT OUT TO SEA TODAY. ANOTHER AREA OF LOW PRESSURE WAS ANALYZED OVER LAKE SUPERIOR. THIS ALBERTA CLIPPER WILL MOVE E-SEWD ACROSS THE UPPER GREAT LAKES. THE EASTERN SEABOARD WILL BE POSITIONED BETWEEN BOTH OF THESE LOWS WITH A WEAK RIDGE RIDGE EXTENDING SOUTHWARD FROM ARCTIC HIGH PRESSURE THAT IS ANCHORED NEAR THE QUEBEC-LABRADOR BORDER. THE FORECAST AREA WILL BE DRY TODAY WHILE MOST LOCATIONS. HIGH CLOUDS WILL INCREASE THIS AFTERNOON AS AN UPPER TROUGH APPROACHES FROM THE OH VALLEY, BUT GENERALLY MOST SUNNY SKIES ARE EXPECTED. THE ONE EXCEPTION IS ALONG THE NJ AND DE COAST WHERE STRATOCU HAS BEEN PERSISTENT. A LOOP OF THE MORNING VISIBLE SATELLITE IMAGERY SHOWED SOME CLEARING ON THE WESTERN EDGE OF THE MARINE CLOUDS ALONG THE COAST FROM ACY NORTHWARD. FORECAST RH FIELDS FROM THE RAP WERE USED AS A PROXY FOR PREDICTING THE EVOLUTION OF THE STRATOCU SINCE THIS MODEL SEEMED TO HAVE HAD A GOOD HANDLE ON IT THIS MORNING. THE RAP SIMULATES THESE CLOUDS EXPANDING SLIGHTLY INLAND IN NJ THIS AFTERNOON, PRESUMABLY IN RESPONSE TO THE DEEPER MIXING ON LAND. MADE ONLY MINOR TWEAKS TO THE TEMPS TODAY, MAINLY DECREASE MAX TEMPS 1-3F ALONG THE IMMEDIATE COAST (DUE TO THE STUBBORN MARINE CLOUDS) AND RAISE MAX TEMPS BY THE SAME MAGNITUDE FARTHER INLAND. OVERALL, MAX TEMPS ABOUT 5F BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... CLOUD COVER WILL INCREASE AND LOWER THROUGH THE NIGHT AHEAD OF AN APPROACHING CLIPPER SYSTEM. NOT MUCH IN THE WAY OF PRECIPITATION IS EXPECTED FOR MOST OF THE AREA THROUGH THE OVERNIGHT HOURS, BUT SOME SNOW SHOWERS MAY BEGIN MAKING THEIR WAY INTO THE FAR NORTHWESTERN AREAS OVERNIGHT AND TOWARD DAYBREAK THURSDAY AS MOISTURE INCREASES AND SOME LOW LEVEL LIFT MOVES INTO THE AREA. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THIS TIME PERIOD WILL BE DOMINATED BY A PAIR OF ARCTIC OUTBREAKS OF VERY COLD AIR RIVALING THE OUTBREAKS FROM JANUARY 2014. THE COMBINATION OF TEMPERATURE AND POSSIBLY ADVISORY LEVEL WIND GUSTS WILL PRODUCE MODERATE TO HIGH IMPACT THREAT FROM WIND CHILLS. THERE ARE ALSO THREE SHOTS AT SNOW IN THE LONG TERM. SINCE TWO OF THEM INVOLVE MILLER B SYSTEMS, THERE REMAINS HIGHER UNCERTAINTY AS TO THEIR IMPACT IN OUR AREA. THE FINAL LOW IS A MORE CONVENTIONAL ONE PREDICTED TO ARRIVE FROM THE SOUTHERN PLAINS. ITS THE LAST IN THE SERIES AND ITS LATITUDINAL SHIFTS WILL IMPACT PTYPE. WE SHOULD HAVE A BETTER HANDLE ON THAT ONE FURTHER IN ADVANCE AS OPPOSED TO VALENTINE`S NIGHT LOW WITH ITS NORLUN TROF FEATURE THAT IS MORE OF A BEAR TO ACCURATELY FORECAST MUCH IN ADVANCE. LIKE LAST NIGHT, THE GFS INITIALIZATION AT 850MB AND 500MB LOOKED SLIGHTLY POORER THAN THE WRF-NMMB AND LIKE LAST NIGHT ITS 925MB INITIALIZATION WAS BETTER. UNLIKE LAST NIGHT THE GEFS MEAN SUPPORTS THE OPERATIONAL GFS AND THE GFS AND ECMWF RUNS ARE PRETTY SIMILAR. THEY WERE USED WITH SOME WPC BLENDING FOR THE LONG TERM. FOR THURSDAY NOW THAT THE GFS HAS JOINED THE OTHER MODELS WITH A MORE SUBDUED SECONDARY CYCLOGENESIS ON THURSDAY, OUR PREDICTED SNOW HAS COME DOWN A NOTCH CLOSER TO THE COAST WITH LESS THAN AN INCH SOUTH OF THE INTERSTATE 78 CORRIDOR. WE KEPT AN INCH TO TWO NORTH BECAUSE THE BURLINGTON WINDEX TOOL IS INDICATING MORE INTENSE SNOW SHOWERS LIKELY. BECAUSE OF THE VORT MAX POSITIONING, THIS MAY OCCUR ANYWHERE IN OUR CWA, BUT THE SOUTHERN PART OF OUR CWA SHOULD HAVE SOME MELTING ISSUES (MAYBE EVEN SOME RAIN DURING LIGHTER INTENSITIES) AS THE MODELS HAVE TRENDED WARMER. ALSO DEEPER MOISTURE IS NORTH AS ARE OUR HIGHEST POPS. WE HAVE EFFECTIVELY DOUBLED POPS BECAUSE OF THE PREDICTED PASSING OF THE VORT MAX. THE COLD BIAS IN BOTH THE 2M AND STAT GUIDANCE TEMPS CONTINUES ON NON PRECIPITATING DAYS. GIVEN THE AFTERNOON ARRIVAL OF THE VORT MAX, WE SIDED WITH HIGHER STAT GUIDANCE FOR MAX TEMPS. FARTHER OFFSHORE DEVELOPMENT ALSO MEANS LESS LINGERING OF PCPN CHANCES. THE TROF AXIS ITSELF IS ALSO A BIT FASTER. POPS WERE REDUCED THU EVENING. AS THE LOW INTENSIFIES OFFSHORE, (IT IS SLOWER THAN LAST NIGHT, NOW ABOUT 20MB/24HRS) THE GRADIENT IS PREDICTED TO TIGHTEN. THE GFS BRINGS WIND ADVISORY LEVEL GUSTS, WHILE THE WRF-NMMB AND ECMWF COME UP A LITTLE SHORT. GIVEN THE DP/DT HAS BEEN FOR LATER INTENSIFICATION, WE KEPT WIND GUSTS BELOW ADVISORY LEVELS. REGARDLESS, MUCH COLDER AIR WILL BE ARRIVING AND WIND CHILL ADVISORY LEVELS MIGHT BE REACHED IN THE POCONOS WITH SUB ZERO WIND CHILL APPARENT TEMPS ELSEWHERE. SINGLE NUMBER MINS SHOULD PREVAIL NORTHWEST OF THE FALL LINE WITH ALL OTHER MINS IN THE MID TEENS OR LOWER. THE THERMAL TROF PASSES FRIDAY MORNING WITH SOME MODIFICATION OF THE AIR MASS STARTING FROM AN EXTREMELY LOW POINT. WINDS SHOULD DECREASE AS THE DAY PROGRESSES. BUT, MAX TEMPS WILL BE LOWER THAN THE NORMAL MIN TEMPS. BANKING ON CLOUDINESS ASSOCIATED WITH THE GREAT LAKES LOW TO HOLD TEMPERATURES UP ON FRIDAY NIGHT. WITH LIGHT WINDS IF THIS DOES NOT OCCUR, OUR MINS, ESPECIALLY NORTH, WILL BE TOO WARM BY AS MUCH AS 10 DEGREES. THEN ALL EYES WILL BE ON THE REDEVELOPMENT OF THE GREAT LAKES LOW. AN EXTREMELY COLD PIECE OF THE PV IS FORECAST TO PASS ACROSS OUR CWA AND INITIATE CYCLOGEN OFF THE MID ATLC COAST. IN FACT BOTH THE CAN GGEM AND ECMWF HAVE A TERTIARY CYCLOGEN UNDERNEATH THE 500MB CLOSED LOW ON SATURDAY NIGHT. BESIDE INCREASING THE NORLUN TROF CHANCES OF AN AXIS OF HEAVIER SNOW (THIS HAS BEEN BOUNCING AROUND SOUNDING RUN TO SOUNDING RUN BETWEEN NJ AND LONG ISLAND), IT TIGHTENS THE GRADIENT TO THE POINT THAT ADVY LEVEL WIND GUSTS WOULD BE REACHED. HIGH WINDS NOT OUT OF THE QUESTION EITHER. BUT, THIS SYSTEM HAS YET TO ENTER CANADA AND WHILE THE GFS AND ECMWF INITIALIZATION LOOKED GOOD, ITS STILL COMING FROM A RATHER DATA SPARSE AREA. COMING FROM FRIDAY`S PERSPECTIVE, THE SOUTHERLY FLOW PRECEDING THIS LOW WILL MAKE SATURDAY FEEL BETTER EVEN THOUGH MAX TEMPS SHOULD STILL BE ABOUT 10 DEGREES COLDER THAN NORMAL. THEN THE TEETH OF THE ARCTIC OUTBREAK IS EXPECTED ON SUNDAY INTO MONDAY AS WE SHOULD EXPERIENCE THE COLDEST FEBRUARY WEATHER SINCE 1996 AND BEYOND THAT WE`D BE GOING BACK TO 1979. VICIOUSLY COLD ON SUNDAY WITH STILL STRONG WINDS AROUND THE DEPARTING LOW. WIND CHILL ADVISORY LEVEL TEMPS MIGHT OCCUR NORTH WITH MORE WIDESPREAD WIND CHILL ADVISORY AND POSSIBLY WIND CHILL WARNING LEVEL APPARENT TEMPS ON SUNDAY NIGHT. HIGH TEMPERATURES ON SUNDAY SHOULD NOT MOVE MUCH AND SUNDAY NIGHT SHOULD BE THE COLDEST NIGHT OF THE OUTBREAK. THERE WILL BE A TEMPERATURE RECOVERY ON MONDAY AND WINDS SHOULD FINALLY DIMINISH. IN FACT TEMPERATURES MAY JUST KEEP ON RISING THROUGH MONDAY NIGHT INTO TUESDAY. A LOW PRESSURE SYSTEM EMERGING FROM THE TENNESSEE VALLEY WOULD BRING PRECIPITATION INTO OUR AREA BY TUESDAY DAY. INITIALLY COLD ENOUGH FOR SNOW. THE MODELS ARE RETROGRADING THE 500MB RIDGE TO THE POINT THAT THIS LOW MIGHT BE ABLE TO CUT NORTHWEST OF US. PLENTY OF MOVING PARTS AND WOULDNT BANK ON THIS. PLUS THE DEEP FREEZE TEMPS LEADING INTO THIS WOULD PROLONG ICING POTENTIAL IF PTYPE IS NOT SNOW. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR TODAY AND THIS EVENING. THE ONE AIRPORT WE HAVE TO WATCH FOR MVFR CIGS THIS AFTERNOON INTO TONIGHT IS ACY. STRATOCU OFF THE WATERS HAD ERODED NEAR ACY JUST AFTER SUNRISE THIS MORNING. HOWEVER, LATEST GUIDANCE TRIES TO BRING THE LOW CLOUDS BACK INLAND TO ACY AFTER 18Z TODAY. CLOUDS WILL INCREASE LATE IN THE DAY AND LOWER TONIGHT. MVFR CIGS MAY BEGIN MOVING INTO THE AREA OVERNIGHT OUT TOWARD ABE/RDG AND DURING THE EARLY MORNING THURSDAY FARTHER EAST. N-NE WINDS AROUND 10 KT THIS MORNING WILL OCCASIONALLY GUST TO 20 KT. WINDS WILL VEER MORE OUT OF THE E-NE THIS AFTERNOON AND EVENING AOB 10 KT. LIGHT AND VARIABLE WINDS OVERNIGHT. OUTLOOK... WEDNESDAY NIGHT...MAINLY VFR. SOME MVFR CONDITIONS POSSIBLE LATE NORTHWEST AIRPORTS. THURSDAY...VFR START. HOWEVER, SNOW COULD REDUCE CONDITIONS INTO THE MVFR OR IFR CATEGORY, ESPECIALLY AT NORTHERN AIRPORTS AND TERMINALS. THURSDAY NIGHT THROUGH FRIDAY NIGHT...MAINLY VFR. VERY STRONG AND GUSTY NORTHWEST WINDS LIKELY EXCEEDING 30 KNOTS. WINDS DECREASING FRIDAY NIGHT. SATURDAY INTO SATURDAY NIGHT...A CHANCE OF SNOW COULD ONCE AGAIN REDUCE CONDITIONS IN THE MVFR OR IFR CATEGORY. INCREASING NORTHWEST WINDS SATURDAY NIGHT. SUNDAY...VFR BUT VERY WINDY (GUSTS COULD EXCEED 40 KNOTS) AND VERY VERY COLD. && .MARINE... SCA WAS ALLOWED TO EXPIRE FOR THE LOWER DE BAY AT 10 AM AS WIND GUSTS HAVE DIMINISHED TO 15 KT OR LESS. SCA CONTINUES FOR THE COASTAL ZONES WITH GUSTS STILL AROUND 25 KT THIS MORNING. SEAS HAVE ARE STILL HIGH THIS MORNING, RANGING FROM 9-13 FT. THE SCA MAY BE ABLE TO BE CONVERTED TO A HAZARDOUS SEAS SCA WITH WINDS BECOME LIGHT LATE IN THE DAY THROUGH THURSDAY MORNING WHILE SEAS WILL STILL REMAIN ELEVATED. OUTLOOK... THURSDAY...SEAS ON THE OCEAN NECESSITATED EXTENDING THE SMALL CRAFT ADVISORY THROUGH THE DAY. SUB SMALL CRAFT ADVISORY ON DELAWARE BAY. THURSDAY NIGHT AND FRIDAY...WE ISSUED A GALE WATCH FOR NORTHWESTERLY GALE FORCE GUSTS. ALSO POSSIBLY MODERATE FREEZING SPRAY. FRIDAY NIGHT...WINDS DECREASING TO SUB SMALL CRAFT ADVISORY AS THE NIGHT PROGRESSES. SATURDAY...WINDS SHOULD BE INCREASING RAPIDLY LATER IN THE DAY AND SATURDAY NIGHT POSSIBLY REACHING GALE CRITERIA. FREEZING SPRAY. SUNDAY...SUSTAINED GALE FORCE WINDS ARE POSSIBLE. STORM FORCE GUSTS POSSIBLE. MODERATE FREEZING SPRAY, POSSIBLY BECOMING HEAVY SUNDAY NIGHT. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR ANZ430-431-450>455. SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ431. && $$ SYNOPSIS...GIGI NEAR TERM...KLEIN SHORT TERM...ROBERTSON LONG TERM...GIGI AVIATION...GIGI/KLEIN MARINE...GIGI/KLEIN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
912 PM CST THU FEB 12 2015 .UPDATE... 800 PM CST EVENING UPDATE... WILL LET WINTER STORM WARNING FOR PORTER COUNTY EXPIRE ON SCHEDULE THIS EVENING...AS LAKE EFFECT SNOW HAS WEAKENED AND SHIFTED EAST OF THE AREA. OTHER MINOR CHANGES TO FORECAST WAS TO INCREASE CLOUD COVER A BIT AND SLOW TEMPERATURE DROP OFF THIS EVENING WITH CIRRUS AND PATCHY MID CLOUD OVER MUCH OF THE CWA. HEIGHT RISES AND STRONG SUBSIDENCE IN THE WAKE OF THIS MORNING/S STRONG SHORT WAVE DISTURBANCE HAS RESULTED IN SURFACE HIGH PRESSURE SPREADING ACROSS THE MID-MISSISSIPPI VALLEY AND INTO WEST CENTRAL IL THROUGH EARLY THIS EVENING. WEAKENING/BACKING OF LOW LEVEL WIND FIELD AND ASSOCIATED WEAKENING CONVERGENCE OVER LAKE MICHIGAN COMBINED WITH LOWERING SUBSIDENCE INVERSION HAS ALLOWED LAKE EFFECT SNOW TO WEAKEN FROM STRONG SINGLE-BAND EARLIER THIS AFTERNOON TO MUCH LESS INTENSE PARALLEL BAND SHOWERS FOCUSED LARGELY INTO MI/IN EAST OF PORTER COUNTY AT 755 PM. OTHER THAN A FEW LINGERING FLURRIES SNOW HAS ENDED...AND THE WINTER STORM WARNING WILL EXPIRE AT 8 PM CST AS PLANNED. OTHERWISE...CONSIDERABLE MID/HIGH CLOUD COVER...THOUGH THIN IN SPOTS...HAS RESULTED IN TEMPS FALLING OFF MORE SLOWLY THAN FORECAST. HAVE INCREASED CLOUD COVER AND SLOWED THE TEMPERATURE ROLL OFF THROUGH THIS EVENING...THOUGH MINS FROM GOING FORECAST STILL LOOK REASONABLE WITH LIGHT/VARIABLE WINDS IN SURFACE RIDGE AND ANY CLEARING AFTER MIDNIGHT. OTHER THAN AFOREMENTIONED TWEAKS TO HOURLY FORECAST GRIDS...NO SIG CHANGES TO GOING FORECAST FOR TONIGHT. RATZER && .SHORT TERM... 323 PM CST TONIGHT THROUGH SUNDAY... MULTIPLE WINTER CONCERNS OVER THE NEXT FEW DAYS...INCLUDING IN ORDER OF SIGNIFICANCE: ANOTHER SIGNIFICANT LAKE EFFECT EVENT APPEARING LIKELY LATE SATURDAY INTO SUNDAY MORNING...BITTERLY COLD AND WINDY ON VALENTINES DAY AND NIGHT...SNOW SHOWERS WITH AN ARCTIC FRONT FRIDAY NIGHT...AND POSSIBLE LIGHT SNOW ON FRIDAY. TONIGHT...WILL LIKELY BE ABLE TO EXPIRE WSW IN PORTER CO. FOR LAKE EFFECT AS PLANNED OR POSSIBLY EARLIER AS SNOW SHOWERS CONTINUE TO WEAKEN IN INTENSITY. ARCTIC HIGH WILL BE OVERHEAD BUT THEN SHIFT EAST. INCREASING CLOUDS WILL PREVENT A MUCH COLDER NIGHT...THOUGH LOW MINUS SINGLE DIGITS APPEAR A GOOD BET IN TYPICAL COLDER SPOTS...WITH POSITIVE SINGLE DIGITS FOR THE REST OF THE AREA. ON FRIDAY...WARM FRONT TRAILING FROM CLIPPER TRACKING NEAR LAKE SUPERIOR WILL APPROACH AREA...WITH BROAD ASCENT. HAVE CONCERN WITH SOME GUIDANCE...NAMELY ECMWF...KEEPING THINGS DRY...BUT NAM/GFS/GEM FORECAST SOUNDINGS INDICATE ENOUGH SATURATION AND WEAK ASCENT THROUGH DGZ FROM THE LATE MORNING INTO EARLY AFTERNOON MAINLY NORTH OF I-80. SHOULD SEE AN AREA OF LIGHT SNOW LIFTING NORTHEAST...WHICH COULD PUT DOWN A DUSTING IN SPOTS. CONTINUED WARM ADVECTION THROUGH LATE DAY SHOULD ENABLE TEMPS TO RECOVER INTO 20S AREA WIDE. FRIDAY NIGHT...VERY IMPRESSIVE ARCTIC FRONT WILL APPROACH AREA LATE IN THE NIGHT. 850 MB TEMPS OUT AHEAD OF IT ACTUALLY WARM TO LOWER MINUS SINGLE DIGITS CELSIUS...SO -25 TO -30C AIR BEHIND FRONT WILL SHARPEN THERMAL GRADIENT AND QUICKLY STEEPEN LAPSE RATES ALONG AND BEHIND FRONT. ASCENT WILL BE ASSISTED BY VERY POWERFUL MIDLEVEL SHORT WAVE DIVING SOUTHEASTWARD AND NOSE OF 140 KT UPPER JET. THUS EXPECT...SNOW SHOWERS TO BREAK OUT MAINLY AFTER MIDNIGHT AND SPREAD SOUTH. COULD SEE A HALF INCH TO EVEN AS MUCH AS AN INCH IN SPOTS BY DAYBREAK SATURDAY...ESPECIALLY ALONG/SOUTH OF I-88. BUMPED POPS TO MID/HIGH CHANCE IN THIS PERIOD. LOW TEMPERATURES ARE LIKELY TO BE SATURDAY`S HIGH TEMPS WITH MUCH OF THE NIGHT REMAINING NEARLY STEADY FROM FRIDAY HIGHS UNTIL FROPA. SATURDAY AND SUNDAY NOT INCLUDING LAKE EFFECT....THE ARCTIC DAM WILL BREAK ON SATURDAY ...WITH NO MODERATION SHOWN IN GUIDANCE OF -25 TO -27C 850 MB THERMAL TROUGH ARRIVING BY MID DAY ON VALENTINES DAY. TEMPERATURES WILL PLUMMET AS STRONG COLD ADVECTION RAMPS UP. COULD SEE SOME FLURRIES AND SNOW SHOWERS CONTINUE IN THE MORNING AS LIFT WILL STILL BE PROVIDED FROM POWERFUL UPPER VORT OVER AREA...THOUGH ARCTIC AIR MASS WILL BECOME INCREASINGLY DRY. EXTREMELY STRONG PRESSURE GRADIENT BETWEEN 1045 MB+ ARCTIC HIGH OVER NORTHERN PLAINS AND CLIPPER DEEPENING TO SUB 1000 MB OVER EASTERN LAKES WILL RESULT IN NNW WINDS GUSTING TO 35 TO 45 MPH AND POSSIBLY STRONGER ON INDIANA SHORE...WHERE A WIND HEADLINE MAY BE NEEDED PRIOR TO LAKE EFFECT ISSUES. WIND CHILL VALUES WILL FALL TO 10 TO 20 BELOW BY LATE AFTERNOON AND EARLY EVENING. THEN SUBZERO LOWS OUTSIDE OF DOWNTOWN CHICAGO AND NW INDIANA PLUS ONLY SLOWLY DIMINISHING WINDS WILL YIELD WIND CHILLS OF 20 TO 30 BELOW LATE SATURDAY NIGHT INTO SUNDAY MORNING. WILL IN ALL LIKELIHOOD NEED A WIND CHILL ADVISORY STARTING VALENTINES DAY EVENING. DRESS APPROPRIATE FOR DANGEROUS COLD IF YOU HAVE DINNER PLANS SATURDAY NIGHT OR CONSIDER SPENDING THE NIGHT IN WITH YOUR VALENTINE IF YOU HAVEN`T MADE PLANS YET! VERY GRADUAL WARM ADVECTION ON SUNDAY SHOULD ALLOW HIGHS TO RECOVER TO THE HIGH SINGLE DIGITS TO MID TEENS. LAKE EFFECT DISCUSSION FOR SATURDAY INTO SUNDAY...EXTREME 850 MB TO LAKE DELTA TS OF ABOUT 25C AND EQUILIBRIUM LEVELS AT OR OVER 10KFT ARE LIKELY TO RESULT IN IMPRESSIVE LAKE EFFECT SNOW BAND(S) DEVELOPING OVER SOUTHERN LAKE MICHIGAN. WILL STILL NEED TO ASSESS LATEST GUIDANCE CONCERNING OVERALL EVOLUTION...BUT GUIDANCE HAS REMAINED IN EXCELLENT AGREEMENT IN SWINGING BOUNDARY LAYER FLOW FROM NNW SATURDAY AFTERNOON AND EARLY EVENING TO NORTHERLY SATURDAY NIGHT AND THEN NORTH-NORTHEAST TO NORTHEAST ON SUNDAY. STEADY LAKE SNOWS COULD GET INTO PORTER COUNTY AS EARLY AS SATURDAY AFTERNOON. I THEN BROUGHT CATEGORICAL POPS WESTWARD SATURDAY NIGHT INTO SUNDAY MORNING...WITH ACTIVITY WEAKENING OVER NORTHEAST ILLINOIS DUE TO SUBSIDENCE AND INCREASINGLY DRY AIR ON SUNDAY AFTERNOON. POTENTIAL MESOLOW/ENHANCED CONVERGENCE COULD LET SNOW HANG ON A BIT LONGER THAN WOULD OTHERWISE EXPECT. WILL LIKELY NEED SOME SORT OF LAKE EFFECT HEADLINE AND WOULDNT BE SURPRISED WITH NEEDING ANOTHER WARNING FOR AT LEAST PORTER COUNTY GIVEN IMPRESSIVE PARAMETERS. AT LEAST 6 INCHES OF ACCUMULATION APPEAR POSSIBLE FOR THE NORTHERN HALF OF PORTER...WHICH COULD BE CONSERVATIVE. RC && .LONG TERM... 111 PM CST SUNDAY NIGHT THROUGH THURSDAY... HIGH AMPLITUDE RIDING REBUILDS YET AGAIN JUST OFFSHORE OF THE PACIFIC COASTLINE FOR THE EARLY HALF OF THE WEEK. AFTER SOME RECOVERY ON MONDAY...THIS PATTERN SUGGESTS WE WILL REMAIN IN A COLDER NW FLOW PATTERN WITH BELOW NORMAL TEMPERATURES AN OCCASIONAL CHANCE FOR LIGHT SNOW. SURFACE HIGH PRESSURE QUICKLY SHIFTS EAST ON SUNDAY NIGHT OPENING THE DOOR TO A SERIES OF DISTURBANCES IN WEST/NORTHWEST FLOW ALOFT. WARM AIR ADVECTION BEHIND THE DEPARTING HIGH MAY TRIGGER SOME LIGHT SNOW IN OUR WESTERN AREAS SUNDAY NIGHT...BUT THESE DISTURBANCES LOOK TO SPLIT THE AREA WITH ONE WAVES DIGGING SOUTH CLOSER TO THE LINGERING LOW LEVEL BAROCLINIC ZONE THAT BLASTED THROUGH THE AREA ON SATURDAY. SOME OF THIS MAY GRAZE OUR SOUTHERN COUNTIES FROM LASALLE EAST TO BENTON COUNTY INDIANA DURING THE DAY MONDAY. THE OTHER PACIFIC WAVE BY THIS TIME WOULD HAVE TAKEN A MORE ARCTIC ROUTE GRAZES OUR NORTHERN ZONES AND LARGELY PASSES BY TO OUR NORTH. THAT SAID...LIGHT ISENTROPIC LIFT AHEAD OF THE NORTHERN SHORTWAVE KEEPS CHANCES FOR LIGHT SNOW GOING FOR NORTH CENTRAL ILLINOIS MONDAY...THEN ALONG AND NORTH OF I-88 MONDAY NIGHT. MODELS ARE NOT IN GREAT AGREEMENT ABOUT ACCUMULATING SNOW WITH THE SPLIT ENERGY ON MONDAY/MONDAY NIGHT...THUS SOME LOW CHANCE POPS CARRIED. SHOULD BE A CLOUDIER PERIOD NONETHELESS. THE PATTERN THEN BECOMES HIGHLY AMPLIFIED OVER OUR REGION WITH LOW PRESSURE OVER HUDSON BAY WHILE A DEEP UPPER TROUGH DIGS INTO THE FOUR CORNERS REGION/DESERT SOUTHWEST. THE LEADING EDGE OF A COLD FRONT BEGINS OOZING IN TUESDAY. THESE TWO SYSTEMS EVENTUALLY MERGE INTO A UNIFIED TROUGH WHICH PASSES OVER THE REGION ON LATER TUESDAY AND TUESDAY NIGHT. MUCH OF THE FORCING WITH THIS WILL BE SOUTH OF THE AREA LEAVING US COLD AND DRIER WITH SOME LAKE EFFECT SNOWS IN NORTHWEST INDIANA. PICTURE GETS A BIT MORE MUDDLED SNOWFALL WISE MID TO LATE WEEK LEAVING US SUSCEPTIBLE TO CLIPPERS...BUT HAVE HIGHER CONFIDENCE IN CONTINUED COLDER WEATHER AND SOME LAKE EFFECT SNOW. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * NONE IZZI //DISCUSSION...UPDATED 00Z... NORTHWEST WINDS WILL DIMINISH THIS EVENING THEN LIGHTLY BACK AROUND TO SOUTHWEST BY FRIDAY MORNING. SOUTHWEST WINDS WILL GRADUALLY PICK UP THURSDAY MORNING WITH SOME OCCASIONAL GUSTS INTO THE MID- UPPER TEENS DURING THE AFTERNOON. CLOUD DECK WILL GRADUALLY LOWER AND THICKEN DURING THE DAY IN ADVANCE OF APPROACHING WARM FRONT WITH SOME FLURRIES OR LIGHT SNOW POSSIBLE FRIDAY AFTERNOON. FOR NOW JUST CARRIED PREVAILING FLURRIES BUT CERTAINLY COULDN`T RULE OUT A PERIOD OF LIGHT SNOW WITH SOME VSBY REDUCTIONS AND A DUSTING OF ACCUMULATION. IF SNOW IS A BIT MORE ROBUST THEN COULD SEE MVFR CIGS DEVELOP TOWARD FRIDAY EVENING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 03Z... * LOW-MEDIUM CONFIDENCE IN SNOW POTENTIAL AND INTENSITY FRIDAY AFTERNOON AND ATTENDANT MVFR CIGS POTENTIAL * HIGH CONFIDENCE IN AL THE REST IZZI //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...PRIMARILY VFR. STRONG/GUSTY NORTHWEST WINDS. SUNDAY...CHANCE OF MVFR CIGS/FLURRIES. MONDAY THROUGH WEDNESDAY...PRIMARILY VFR. IZZI && .MARINE... 425 PM CST HIGHER WIND SPEEDS STILL IN PLACE ACROSS THE ENTIRE LAKE AS A FAIRLY TIGHT PRESSURE GRADIENT REMAINS OVERHEAD...WHILE HIGH PRESSURE MOVES SOUTHEAST OVER THE REGION. DO EXPECT THE GRADIENT TO RELAX RATHER QUICKLY THIS EVENING...AND WITH WINDS DIMINISHING WHILE BECOMING MORE WESTERLY. THESE LIGHTER WINDS WILL BE ON THE BRIEF SIDE AS SOUTHWEST WINDS INCREASE ONCE AGAIN ON FRIDAY OUT AHEAD OF AN APPROACHING LOW FROM THE NORTHWEST. EXPECT WINDS TO 30 KT ONCE AGAIN ON FRIDAY...BUT BECOMING MORE WEST AND NORTHWEST BY FRIDAY EVENING. DEPARTING LOW PRESSURE AND THEN BUILDING HIGH PRESSURE FROM THE NORTHWEST WILL ALLOW FOR WINDS TO CONTINUE INCREASING LATE FRIDAY NIGHT INTO SATURDAY MORNING...WITH GALES APPEARING LIKELY. HAVE NORTHWEST TO NORTH GALES TO 45 KT MENTIONED IN THE FORECAST...BUT COULD SEE AN UPWARD TREND OCCURRING WITH STORM FORCE WINDS DEFINITELY NOT OUT OF THE QUESTION DURING THE DAY ON SATURDAY. A GALE WATCH HAS BEEN ISSUED FOR THE OPEN WATERS AND THE NEARSHORE WATERS DURING THIS TIME...WITH WINDS DIMINISHING SATURDAY NIGHT. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 4 AM FRIDAY. GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...6 AM SATURDAY TO 3 AM SUNDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 836 PM CST Thu Feb 12 2015 .UPDATE... ISSUED AT 830 PM CST THU FEB 12 2015 Arctic high pressure centered over our area early this evening has allowed winds to subside with an increase in cirrus from northwest to southeast as our next weather system moves into the Missouri River Valley. Early evening temperatures have fallen off but not as quickly as thought as the thicker cirrus has kept the numbers in check early this evening. Weather system to our west responsible for the increase in clouds this evening was producing some scattered areas of light snow over west central and southwest Iowa this evening with both the HRRR and Rapid Refresh models keeping the light snows to our west before it diminishes as it heads east into extreme west central IL Friday morning. Current forecast has this well handled this evening, so other than the usual tweaks to the early evening temperatures, no other changes were needed that would require an updated ZFP at this time. && .SHORT TERM...(Tonight) ISSUED AT 252 PM CST THU FEB 12 2015 Latest water vapor imagery shows broad northwesterly flow over the Midwest, with numerous weak short-waves embedded within the pattern. Next wave of interest to the weather across central Illinois is currently located over western North Dakota and is expected to track S/SE to the Missouri/Iowa border by 12z. 20z/2pm surface obs show light snow falling along/ahead of this feature across the Dakotas. As the wave tracks southeastward, it is expected to shear/weaken with time, resulting in only very minor lift arriving across the western KILX CWA late tonight. With forecast soundings remaining unsaturated, have opted to remove mentionable PoPs overnight in favor of just a chance of flurries along/west of a Galesburg to Jacksonville line. Given initially mostly clear skies and diminishing winds, temperatures will quickly bottom out in the single digits and teens by mid to late evening. As clouds increase and a light southerly return flow begins to develop late, readings will likely rise a couple of degrees toward dawn, especially west of the I-55 corridor. && .LONG TERM...(Friday through Thursday) ISSUED AT 252 PM CST THU FEB 12 2015 An extended period of colder to much colder than normal conditions is expected across central and southeast Illinois, lingering at least through the end of next week. Persistent ridging up to Pacific coast into Alaska and downstream troffing over at least the eastern half of North America will help ensure this fact. Periodic waves in the predominantly northwest upper-level level flow will be accompanied by reinforcing shots of cold air, and possibly some light snow or flurries. The upper troffing will dig enough to our west by next Monday/Tuesday to at least pose the risk of a stronger system moving our way, but recent model trends have been pushing this system further south. Temperatures will briefly moderate Friday ahead of our next major clipper type wave for Saturday. A weaker wave will pass mainly to our north of Friday, which may bring some flurries to northern sections of the forecast area, but no significant snowfall is anticipated. Saturday`s clipper is potent, but will pass far enough to our north/east to be a minimal snowfall threat. The more notable impact with its passage will be winds gusting over 30 mph Saturday into Saturday night. These winds will help usher in bitterly cold sub-zero wind chill temperatures for the entire forecast area Saturday night into Sunday. A few waves in the broader North American trof expected to be in place for early next week will come toward the area from a more westerly or even southwesterly direction. This track should allow these waves to have more moisture to work with as far as being snow producers. However, model trends have pushed the main baroclinic zone/storm track much further south, which should greatly diminish the local threat of significant snow accumulation Monday into Tuesday. Since the system/systems with the early week waves has/have the potential to be significant, will continue to keep a close eye on later guidance. However, at this point, the model trends are looking more optimistic as far as keeping the significant precipitation away from the forecast area. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 505 PM CST THU FEB 12 2015 VFR conditions are expected thru this forecast period (00z Sat). Other than some bkn-ovc cirrus tonight into Friday, the weather will remain quiet into Friday as Arctic high pressure tracks off to our east by morning. Surface winds will continue to diminish out of the northwest this evening and then become light and variable late tonight. Look for southerly winds on Friday at 8 to 15 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...Barnes LONG TERM...Bak AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 PM CST TUE FEB 10 2015 .UPDATE... FOR EVENING UPDATE... MADE SOME CHANGES TO AERIAL COVERAGE IN POPS/WX FOR TONIGHT...WITH FOCUS INITIALLY ALONG RELATIVELY NARROW BAND SEEN IN RADAR RETURNS FROM PEORIA NORTHEAST TO NEAR JOLIET AT 815 PM. 00Z SOUNDING FROM DVN SHOWS IMPRESSIVE WARM LAYER OF +6 C AT ABOUT 870 MB...WITH STEEP LAPSE RATES FROM THERE TO NEAR 700 MB...AND ANOTHER LAYER OF STEEP LAPSE RATES ABOVE ABOUT 640 MB. GIVEN THESE STEEP LAPSE RATES ALOFT IT/S NOT SURPRISING TO SEE A CONVECTIVE NATURE TO RADAR RETURNS ACROSS THE AREA THIS EVENING...WITH 35-40 DBZ RETURNS NOTED IN "CORES" SOUTHWEST OF KLOT. THIS APPEARS TO BE IN LINE WITH LOW LEVEL THERMAL ADVECTION AXIS PER 00Z RAOB ANALYSIS AND SPC MESOANALYSIS DATA. GIVEN THERMAL PROFILES WOULD EXPECT RAIN/FREEZING RAIN TO BE A PRIMARY PRECIP TYPE...THOUGH THE CONDITIONALLY UNSTABLE LAYER ALOFT APPEARS TO BE PRODUCE MAINLY GRAUPEL/ICE PELLETS WHERE THE STRONGER RADAR RETURNS ARE. THANKFULLY...THE MUCH WEAKER RETURNS ELSEWHERE AND DRY LOW LEVELS WERE RESULTING IN LITTLE/NO PRECIPITATION REACHING THE GROUND PER SURFACE OBS AND PING PROJECT DATA. PARENT SHORT WAVE CIRCULATION CLEARLY SEEN IN REGIONAL RADAR MOSAIC LIFTING EAST-NORTHEAST ACROSS WI...AND EXPECT MOST OF THE CURRENT LIGHT BANDED PRECIP WILL MOVE EAST OF THE AREA BY/SHORTLY AFTER MIDNIGHT. SECONDARY SHORT WAVE CURRENTLY HEADING INTO SOUTHWEST MINNESOTA WILL DIG TOWARD THE AREA OVERNIGHT HOWEVER...WITH SURFACE LOW PRESSURE CURRENTLY OVER MINNESOTA MOVING EAST AND THE TRAILING SURFACE TROUGH/OCCLUDED FRONT MOVING INTO THE CWA LATE TONIGHT/WEDNESDAY MORNING. AMPLE LOW-LEVEL MOISTURE EXISTS WITHIN THE LOW LEVEL FRONTAL ZONE...NOTED IN EXTENSIVE AREA OF LOW CLOUDS ACROSS IA/MN/WI. FORECAST SOUNDINGS SUGGEST POTENTIAL FOR AT LEAST SOME PATCHY LIGHT FREEZING DRIZZLE OVERNIGHT INTO EARLY WEDNESDAY AS SHORT WAVE PRODUCES LARGE SCALE ASCENT ATOP SHALLOW MOIST NEAR SURFACE LAYER...WHICH FORECAST SOUNDINGS INDICATE WILL NOT BE COOL ENOUGH FOR ICE NUCLEI. THEREFORE...LIGHT FREEZING DRIZZLE POTENTIAL INCREASES AFTER MIDNIGHT INTO EARLY WEDNESDAY MORNING...BEFORE FRONTAL PASSAGE AND GUSTY NORTHWEST WINDS DRY THINGS OUT. RATZER && .SHORT TERM... 345 PM CST THROUGH THURSDAY... MAIN FORECAST CONCERNS ARE WITH PRECIP/PRECIP TYPE LATE THIS AFTERNOON INTO THE OVERNIGHT...LINGERING LIGHT SNOW SHOWERS ON THURSDAY...AND THEN WITH ACCUMULATING LAKE EFFECT SNOW EXPECTED LATE WEDNESDAY NIGHT INTO THURSDAY. LATEST RADAR MOSAIC SHOWING LEADING EDGE OF PRECIP STILL STEADILY PROGRESSING EAST ACROSS EASTERN IOWA...AND CURRENTLY APPROACHING FAR NORTHWEST ILLINOIS AT THIS TIME. THIS PRECIP IS RIDING ALONG WARM ADVECTION WING...OUT AHEAD OF THE SOUTHERN END OF A FAIRLY STOUT VORT MAX MOVING THROUGH MINNESOTA AND WISCONSIN. WITH THIS VORT MAX SHIFTING EAST THIS AFTERNOON INTO THE EVENING...LARGE SCALE ASCENT WILL CONTINUE TO QUICKLY INCREASE ACROSS THE CWA. PREVIOUSLY MENTIONED DRY AIR IN PLACE IS NOW APPEARING TO BE TOO MUCH A FACTOR AS FORCING SHOULD BE ABLE TO OVERCOME IT. THIS WILL LIKELY OCCUR AS SOON AS 23-00Z FOR THE NORTHWEST CWA AND THEN MORE TOWARDS THE 2-3Z TIME FRAME FOR NORTH CENTRAL AND NORTHEAST ILLINOIS. DID BRING POPS FURTHER SOUTH TOWARDS THE I80 CORRIDOR BRIEFLY THIS EVENING...BUT STILL THINK THE BEST CHANCES FOR PRECIP WILL BE ALONG AND NORTH OF THE I88 CORRIDOR. RAISED POPS TO HIGH CHANCE POPS...AND LIMITED THEM HERE DUE TO OVERALL DURATION AND COVERAGE WHICH APPEAR TO BE SMALL. UPON SATURATION...THERMAL PROFILES WOULD SUGGEST A BRIEF MIX OF SNOW AND SLEET AT THE ONSET BEFORE A QUICK TRANSITION OVER TO ALL SNOW OCCURS. EXPECT THIS TREND TO CONTINUE THROUGH THE EVENING BUT WITH ONCE AGAIN SMALLER WINDOW OF PRECIP EXPECTED...DONT ANTICIPATE MUCH IN TERMS OF ANY ACCUMULATION. AT MOST WOULD A COUPLE OF TENTHS OF AN INCH OF SNOWFALL. DEEPER MOISTURE IS LOST MORE TOWARDS 5Z ACROSS MUCH OF THE CWA...BUT STILL HOVERING AROUND THE POSSIBILITY FOR INCLUSION OF CRYSTALS. THIS WILL OCCUR THE DEPARTURE OF THE INITIAL WAVE...BUT WITH THE ARRIVAL OF AN ADDITIONAL WAVE AND SURFACE TROUGH/FRONT INTO EARLY WEDNESDAY MORNING. COVERAGE AND DURATION OF ADDITIONAL PRECIP SHOULD ALSO BE SMALL...BUT WITH SNOW AND FREEZING DRIZZLE THEN POSSIBLE. ANY LINGERING PRECIP SHOULD BE DEPARTING WEDNESDAY MORNING...BUT WITH A SLIGHT POSSIBILITY FOR FOR ADDITIONAL SCATTERED LIGHT SNOW SHOWERS POSSIBLE IN THE AFTERNOON. LARGE UPPER LEVEL TROUGH WILL BE DIGGING SOUTH ACROSS THE REGION WEDNESDAY NIGHT...AS A STRONG VORT MAX ROUNDS THE BASE OF THIS TROUGH. THIS WILL MARK THE ARRIVAL OF A MUCH COLDER AIRMASS AND WITH THIS STRONG VORT MAX MOVING ACROSS THE AREA...SNOW SHOWERS WILL LIKELY REDEVELOP WEDNESDAY NIGHT. OF MORE CONCERN IS WITH THE LAKE EFFECT SNOW SHOWERS EXPECTED ACROSS NORTHWEST INDIANA...LATE WEDNESDAY NIGHT INTO MUCH OF THURSDAY. AS THIS COLDER AIR SPILLS SOUTH ACROSS THE LAKE WEDNESDAY NIGHT...THERMODYNAMICS OVER THE LAKE BECOME HIGHLY CONDUCIVE FOR MODERATE TO HEAVY LAKE EFFECT SNOW ACROSS THE SOUTHERN END OF THE LAKE. IMPRESSIVE INVERSION HEIGHT AS WELL AS EVEN MORE IMPRESSIVE DELTA TS COINCIDING WITH STRONG SYNOPTIC LIFT AND LIKELY STRONG CONVERGENCE WILL ALL BE PRESENT...BUT WITH CONFIDENCE AS TO WHERE THE BEST SNOW WILL DEVELOP IS STILL ON THE LOWER SIDE. AM CONFIDENT THAT PORTER COUNTY WILL OBSERVE SNOW BUT AM NOT AS CONFIDENT WITH THE DURATION OF THE LIKELY HEAVIER SNOW. CURRENT THINKING/FORECAST IS FOR LAKE EFFECT TO DEVELOP LATE THURSDAY NIGHT INTO WEDNESDAY MORNING WITH THE BEST ACCUMULATION DURING THIS TIME. BASED ON THIS...HAVE ADVISORY LEVEL SNOWFALL TOTALS ACROSS PORTER COUNTY. IF LAKE EFFECT SNOWBAND WERE TO SETUP ACROSS PORTER COUNTY WHICH IS STILL A DEFINITE POSSIBILITY...THEN TOTALS COULD EASILY EXCEED 6 INCHES. WILL NEED TO MONITOR THIS PERIOD FOR THE POTENTIAL OF HIGHER SNOWFALL TOTALS AND WITH STRONG NORTHERLY WINDS ALSO EXPECTED...THEN BLOWING AND DRIFTING SNOW COULD EASILY BECOME ISSUES. AS HIGH PRESSURE BUILDS ACROSS THE REGION AND LOW LEVEL FLOW BACKS...LAKE EFFECT SHOULD DIMINISH THURSDAY EVENING. RODRIGUEZ && .LONG TERM... 345 PM CST THURSDAY NIGHT THROUGH TUESDAY... HIGH PRESSURE IN PLACE AND THIS COLDER AIRMASS WILL LIKELY PRODUCE LOW TEMPS IN THE SINGLE DIGITS AND WITH LOCATIONS ACROSS NORTH CENTRAL ILLINOIS MORE THAN LIKELY FALLING BELOW ZERO. BRIEF LULL IN THE SNOW WILL END ON FRIDAY AS ANOTHER WAVE PUSHES THROUGH THE REGION...PRODUCING LIGHT ACCUMULATIONS OVER THE ENTIRE CWA. ANOTHER PUSH OF COLDER AIR IS APPEARING LIKELY FOR THE WEEKEND AS ANOTHER LARGE TROUGH DIGS ACROSS THE REGION. DID LOWER TEMPS BELOW GUIDANCE AS A COLDER TREND IS MORE FAVORED. THIS WILL ALSO HELP PRODUCE ANOTHER GOOD SETUP FOR LAKE EFFECT SNOW DEVELOPMENT ACROSS NORTHWEST INDIANA ESPECIALLY SATURDAY AND SATURDAY NIGHT...WITH SEVERAL INCHES OF SNOW A DISTINCT POSSIBILITY DURING THIS PERIOD. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * MVFR CIGS DEVELOPING OVERNIGHT AND CONTINUING THRU THE PERIOD. * POSSIBLE IFR CIGS THRU MID MORNING. * POSSIBLE LIGHT FREEZING DRIZZLE TOWARD DAYBREAK. * STRONG/GUSTY NORTHWEST WINDS DEVELOPING LATE MORNING AND CONTINUING THRU THE PERIOD. * CHANCE OF SNOW SHOWERS WEDNESDAY EVENING/NIGHT. CMS //DISCUSSION...UPDATED 06Z... LOW PRESSURE OVER THE UPPER MIDWEST WILL MOVE ACROSS THE NORTHERN LAKES THIS MORNING. A TRAILING COLD FRONT WILL MOVE ACROSS THE TERMINALS LATE THIS MORNING. SOUTHERLY WINDS AHEAD OF THIS LOW WILL SHIFT MORE WESTERLY AFTER SUNRISE AND THEN TO THE NORTHWEST AFTER THE COLD FRONT PASSES. SPEEDS UP TO 10KTS OVERNIGHT WILL INCREASE TO 10-15KTS LATER THIS MORNING. BUT ONCE WINDS SHIFT TO THE NORTHWEST...SPEEDS WILL INCREASE TO 15-18KTS WITH GUSTS INTO THE MID/UPPER 20 KT RANGE. AS COLDER AIR SPREADS ACROSS THE AREA WEDNESDAY NIGHT...SPEEDS/GUSTS WILL LIKELY INCREASE FURTHER. VFR CIGS WILL LOWER TO MVFR FROM WEST TO EAST OVERNIGHT AS THE LOW LEVELS SATURATE. ITS POSSIBLE CIGS MAY LOWER TO IFR AND IF THIS OCCURS...IT WOULD MOST LIKELY BE AFTER DAYBREAK AND AHEAD OF THE COLD FRONT...BUT CONFIDENCE IS LOW FOR IFR CIGS. AS CIGS LOWER TOWARD LOW MVFR BY DAYBREAK...SOME PATCHY FREEZING DRIZZLE IS ALSO POSSIBLE BUT CONFIDENCE IS ALSO LOW. TEMPS MAY ALSO WARM TO NEAR OR JUST ABOVE FREEZING BY 12Z-14Z...LIMITING ANY POTENTIAL ICING POTENTIAL...SHOULD THE DRIZZLE MATERIALIZE. LATER WEDNESDAY EVENING...AS THE COLDER AIR SPREADS ACROSS THE AREA...LOW LEVEL INSTABILITY LOOKS SUFFICIENT FOR SOME SNOW SHOWERS AND WHILE OVERALL DURATION COULD BE JUST A FEW HOURS... KEPT A LONGER DURATION PROB GOING FOR UNCERTAIN TIMING. CMS //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH FOR MVFR CIGS DEVELOPING OVERNIGHT...MEDIUM FOR TIMING. * LOW FOR IFR CIGS OVERNIGHT/WEDNESDAY MORNING. * LOW FOR LIGHT FREEZING DRIZZLE TOWARD DAYBREAK. * HIGH FOR WINDS THRU THE PERIOD. * MEDIUM FOR SNOW SHOWERS WEDNESDAY EVENING/NIGHT...LOW FOR TIMING/DURATION AND SPECIFIC VIS REDUCTIONS. CMS //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... * THURSDAY...MVFR CIGS POSSIBLE EARLY. STRONG/GUSTY NORTHWEST WINDS. * FRIDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. WEST/SOUTHWEST WINDS. * SATURDAY...CHANCE OF FLURRIES. MVFR POSSIBLE. VERY STRONG/GUSTY NORTHWEST WINDS. * SUNDAY...DRY/VFR. WEST/SOUTHWEST WINDS. * MONDAY...MVFR POSSIBLE. SOUTHWEST WINDS. KJB && .MARINE... 322 PM CST MULTIPLE MARINE CONCERNS AS WE ENTER A VERY COLD AND ACTIVE PATTERN. THIS EVENING...THERE COULD BE BRIEF WINDOW OF NEAR SMALL CRAFT CONDITIONS ALONG THE FAR NORTHEAST ILLINOIS SHORE AS SOUTHEAST WINDS INCREASE TO 15 TO 25 KT. WINDS WILL THEN SHIFT SOUTHERLY ON THE ENTIRE LAKE AS A WEAK LOW OVER THE UPPER MIDWEST APPROACHES. THERE COULD BE A FEW GUSTS TO 30 KT ON THE NORTHERN HALF OF THE LAKE TONIGHT IN THE PEAK OF THE SOUTHERLY FLOW. A STRONG COLD FRONT TRAILING FROM THE LOW WILL SWEEP ACROSS THE LAKE BY MID DAY WEDNESDAY OR SO...WITH AN EXPANSIVE 1040+ MB ARCTIC HIGH SPREADING IN FROM THE NORTHERN PLAINS BEHIND IT. VERY TIGHT PRESSURE GRADIENT AND BITTERLY COLD AIR MASS WILL ENABLE WINDS TO QUICKLY RAMP UP TO GALE FORCE BY EARLY WEDNESDAY EVENING FOR THE OPEN WATERS THEN LATER IN THE EVENING FOR THE NEARSHORE. IN ADDITION...HEAVY FREEZING SPRAY WILL DEVELOP AS AIR TEMPERATURES PLUMMET. HAVE ISSUED A GALE WARNING AND HEAVY FREEZING SPRAY WARNING FOR THE LAKE WEDNESDAY EVENING/NIGHT INTO THURSDAY AFTERNOON...WITH A SMALL CRAFT LEADING UP TO THE GALE WARNING FOR THE NEAR SHORE WEDNESDAY AFTERNOON AND EVENING. EXPECTING PEAK GUSTS UP TO 40 KT WITH THIS EVENT...AND THERE IS SOME POTENTIAL FOR UP TO 45 KT IN/NEAR THE LAKE EFFECT CONVERGENCE BAND EARLY THURSDAY MORNING. THERE WILL BE ONLY A BRIEF CALMER PERIOD THURSDAY NIGHT INTO FRIDAY...FOLLOWED BY YET ANOTHER STRONG ARCTIC FRONT SWEEPING ACROSS THE LAKE FRIDAY EVENING/NIGHT. VERY SIMILAR SETUP TO WEDNESDAY NIGHT INTO THURSDAY BUT AN EVEN TIGHTER PRESSURE GRADIENT DUE TO STRONGER LOW PRESSURE TO THE EAST SHOULD RESULT IN AT LEAST GALES TO 45 KT AND HEAVY FREEZING SPRAY. WINDS...WAVES AND FREEZING SPRAY WILL DIMINISH LATER SATURDAY NIGHT INTO SUNDAY AS THE ARCTIC HIGH MOVES OVER THE LAKE. RC && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM WEDNESDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...NOON WEDNESDAY TO MIDNIGHT THURSDAY. HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...MIDNIGHT THURSDAY TO 3 PM THURSDAY. GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...MIDNIGHT THURSDAY TO 3 PM THURSDAY. GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 PM WEDNESDAY TO 3 PM THURSDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1103 PM CST Tue Feb 10 2015 .UPDATE... ISSUED AT 825 PM CST TUE FEB 10 2015 Fast moving weather system passing to our north has spread a band of mid level clouds east into central Illinois this evening. ILX and DVN 00z soundings indicating a fairly substantial (4-6 deg C) around 850 mb or approx 5000 feet above ground. Have had some reports of sleet and even some brief light freezing rain/mist near Altona in northern Knox county over the past hour with the higher dBZs now headed towards Lacon where a brief period of sleet will be possible over the next half hour. The band of very light precip was tracking east at about 35 to 40 mph so its not going to be around our area too much longer. Have updated the ZFP to include the potential for a brief period of sleet and possibly a little light snow, but based on current and forecast soundings, the better bet is with the sleet for the next hour. Otherwise, cloud cover and a southerly wind tonight should help keep temperatures from falling off too much further before a cold front, one of 3 strong fronts to push across our area over the next week, tracks through central Illinois just before dawn on Wednesday setting up our area for what appears to be a windy and very cold stretch of weather. && .SHORT TERM...(Tonight) ISSUED AT 258 PM CST TUE FEB 10 2015 Stratocumulus clouds 1.5-2k ft are now west of I-55 and eroding and will continue to decrease toward the nw over IL river valley late this afternoon into early this evening due to influence of high pressure ridge axis into IL. HRRR model has been handling the clearing of low clouds well and will continue to follow its lead. Broken to overcast mid level clouds 8-12k ft over IA and far nw IL will spread east across central IL during this evening especially north of I-72 where skies become mostly cloudy. These clouds ahead of 1010 mb low pressure along the eastern ND/SD border will track ene to the Keweenaw peninsula in upper MI by 12Z/6 am Wed with its cold front moving toward the IL river. Meanwhile southeast IL will likely stay in the clear most of this evening with skies becoming partly cloudy overnight in southeast IL. Light mix of precipitation over eastern IA and moving east into WI and far NW IL at mid afternoon. Forecast models keep light precipitation north of I-80 tonight over northern IL. Lows tonight in the upper 20s to near 30F with mildest readings from Springfield southwest. ESE winds less than 10 mph to veer ssw during overnight and turn WNW nw of IL by sunrise behind cold front. && .LONG TERM...(Wednesday through Tuesday) ISSUED AT 258 PM CST TUE FEB 10 2015 The extended will be dominated by large temperature variations, highlighted by two surges of Arctic air into the western Great Lakes and eastern CONUS. Precipitation will be light with any shortwaves through Monday. The upper ridge along the West Coast will remain a semi-permanent feature over the 5 to 6 days, with a long wave trough east of the Continental Divide. A brief push of warm air into the area tonight ahead of the first cold front should help Wednesday start out with rising temps possibly even before sunrise. The cold front could start pushing across our western counties shortly after sunrise, but the affects of the cold air will be delayed across the rest of the area until afternoon when the northwest winds increase in the strong cold air advection. A few light snow showers or flurries could develop Wed afternoon NE of CMI to DNV where a weak shortwave helps provide some lift in the advancing cold air. A better chance for snow showers in our area looks to be Wed night as a strong 500mb vort max dives south into IL. Any snow accums would be very light and mainly confined to areas NE of BMI to MTO. Flurries could extend as far west as Springfield and Taylorville, depending on available moisture. Wind chills later Wed night will drop into the -5 to -15F range, which is just outside of our advisory levels. However, those wind chill numbers are for the sustained winds, and gusts to 30 mph could easily push wind chills much colder than that at times. Thursday will be a blustery day with NW winds of 20-25 and gusts to 35 mph. Some flurries cold linger east of I-57, but the shortwave aloft will depart east of IL early in the day to help shut down potential for precip. Another brief warmup is indicated for Friday, as highs climb toward freezing in the south and into the upper 20s north. The strongest surge of Arctic air this week is expected late Friday night and Saturday, as a deep closed low drops straight south from the upper latitudes into the Great Lakes region. The coldest air, with 850 mb temperatures around -25 to -28C, will be over our area on Saturday. Strong N winds of 25 mph gusting to 40 mph will put wind chills into the advisory criteria between -15F and -20F starting Saturday morning across the northern CWA. Those bitterly cold wind chills appear likely all the way through mid-morning on Sunday. Temperatures on Sunday will warm slightly, but still remain well below normal in the teens to around 20. Washington`s Birthday/Monday looks to be much warmer with highs into the low to mid 30s as a storm system approaches southern Illinois. Some indications are for a period of rain or snow in portions of central IL, with a band of measurable snow possible. The track of that system has shifted farther south in the 12z GFS, keeping light snow confined to areas south of I-72, but the ECMWF still has the effects of the storm reaching well into IL with rain/snow south and snow north. Will keep chance PoPs across the entire area Monday night for now. Beyond that, there are indications of yet another push of cold air for late Tuesday and Tuesday night. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1100 PM CST TUE FEB 10 2015 VFR cigs expected to deteriorate to MVFR cigs between 06z-09z from northwest to southeast as a fast moving frontal boundary sweeps across the region. Latest satellite data and upstream surface observations indicate the leading edge of the MVFR cigs were already pushing towards the Mississippi River and based on the present movement should be approaching PIA around 06z and be into our eastern forecast sites by no later than 08z. Cigs initially were around 2500 feet but lower to between 1200-2000 feet over parts of central Iowa, which should translate east into our area during the early morning hours. Soundings also indicate the potential for some tempo IFR cigs by late morning into the afternoon hours, especially across our northern TAF locations. Models not as aggressive in clearing to our northwest late in the afternoon so will keep the MVFR cigs going into at least the early evening hours. Surface winds will veer more into a southerly direction overnight with speeds of 5 to 10kts and the switch into the west and northwest and increase in speed to between 15 and 20 kts by late morning with gusts around 25 kts at times during the afternoon and early evening. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...07 LONG TERM...Shimon AVIATION...Smith
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1035 AM MST WED FEB 11 2015 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 246 AM MST WED FEB 11 2015 UPPER FLOW WILL BE NORTHWEST THROUGH FRIDAY NIGHT WITH A AMPLIFIED RIDGE OVER THE WESTERN CONUS. SURFACE HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS TODAY AND TONIGHT. A TROUGH WILL MOVE INTO EASTERN COLORADO THURSDAY/THURSDAY NIGHT AS HIGH PRESSURE SHIFTS EAST. HIGH PRESSURE WILL MOVE INTO THE REGION BEHIND THE EXITING SURFACE TROUGH FRIDAY/FRIDAY NIGHT. SUBSIDENCE WILL FOLLOW THE EXITING SHORTWAVE THIS MORNING AND CONTINUE THROUGH TONIGHT. A WEAK SHORTWAVE IS NOTED IN THE FLOW ON THURSDAY BUT MOISTURE IS WELL TO THE EAST OF THE FA SO THAT PRECIPITATION SHOULD BE UNLIKELY. SUBSIDENCE FOLLOWS THE EXITING SHORTWAVE THURSDAY NIGHT AND CONTINUES THROUGH FRIDAY NIGHT. AS A RESULT, ALL PERIODS WILL BE DRY WITH NIL POPS. NAM BOUNDARY LAYER RH INCREASES TO 90 PERCENT AS THE COLD FRONT MOVES INTO THE FA THIS MORNING. THE HRRR INDICATES CEILINGS OF AROUND 1000FT. THE LOWER CEILINGS WILL MOVE OUT OF THE SOUTHERN FA BY 17Z ACCORDING TO THE HRRR. 850 TEMPERATURES INDICATE SEASONABLE TEMPERATURES TODAY IN THE MID 40S AND THEN WARMING UP TO THE LOWER 60S IN EASTERN COLORADO THURSDAY WITH MID 50S IN NORTHWEST KANSAS. MAX TEMPERATURES FRIDAY SHOULD RISE TO NEAR 60. MIN TEMPERATURES SHOULD COOL TO THE LOWER TO MID 20S TONIGHT AND THEN MODERATE TO THE LOWER 30S THURSDAY AND FRIDAY NIGHTS. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 246 AM MST WED FEB 11 2015 SATURDAY THROUGH TUESDAY WILL SEE TEMPERATURES RETURNING TO MORE NORMAL VALUES AS A COOLER AIR MASS MOVES OVER THE AREA BEGINNING SATURDAY...AS WELL AS A CHANCE FOR PRECIPITATION EARLY NEXT WEEK. OVER THE WEEKEND THE UPPER LEVEL RIDGE THAT HAS BEEN SITUATED OVER THE GREAT BASIN WILL BE PUSHED BACK WEST AS A STRONGER UPPER LEVEL TROUGH MOVES SOUTHEAST OUT OF CANADA. THE TROUGH WILL DEEPEN AS IT MOVES SOUTHEAST ACROSS THE CONUS. AS IT DOES SO THE UPPER LEVEL FLOW WILL RESEMBLE MORE OF A SPLIT FLOW SETUP...PRIOR TO THE TROUGH REACHING THE HIGH PLAINS. IF THIS PATTERN DOES DEVELOP THERE WILL BE VERY LITTLE CHANCE FOR PRECIPITATION MONDAY NIGHT DUE TO THE UPPER LEVEL FORCING GOING AROUND THE AREA. HOWEVER WILL LEAVE IN THE CONSENSUS OF MINIMAL CHANCES FOR PRECIPITATION AS THE TROUGH MOVES THROUGH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1026 AM MST WED FEB 11 2015 VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. A REINFORCING SHOT OF COOLER AIR OVERNIGHT WILL SHIFT WINDS AROUND TO NORTHEAST AND BE ACCOMPANIED BY SOME MID AND HIGH CLOUDS. SREF SHOWING LOW PROBABILITIES FOR MVFR CEILINGS AT KMCK AROUND SUNRISE...BUT CONFIDENCE IS LOW AND KEPT THEM VFR IN THE TAF. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...JTL AVIATION...024
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1117 AM CST Wed Feb 11 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 325 AM CST WED FEB 11 2015 Next in a series of cold fronts making its way southward toward the CWA at this hour. Increasing northerly winds and stratus are expected Eastern Kansas through the morning hours. Strong shortwave also noted over southern Colorado, streaming stratus to the east over Western Kansas, however energy dropping into the back of this system should drive this southward through the day today and leave little impact over our area. Cold air advection continues through the day today. This combined with stratus early should hold high temperatures only in the 30s to near 40 this afternoon, however northerly winds will leave it feeling like highs in the 20s to low 30s. NAM is more aggressive with keeping clouds over the area while HRRR and GFS/EC indicate subsidence and clearing for at least a portion of the day today. Evening hours bring a break in the winds and the clouds, however secondary cold front advances southward across the area after midnight and brings in even colder temperatures in the teens. Given north winds of 15 to 20 mph, also anticipate wind chill values near zero, and as low as -10 near in the far northeastern counties by early Thursday. .LONG TERM...(Thursday through Tuesday) Issued at 325 AM CST WED FEB 11 2015 Northwest flow aloft keeps temperatures as the main challenge into the weekend. Surface high comes in Thursday for decreasing winds, but the cold air in place will keep temps about 10F colder than today. Still appears temps may be rather steady or slowly rise late Thursday night as warm air surges back east ahead of next strong upper wave rotating around the persistent upper level trough in the east. This continues to suggest a much warmer Friday than recent days, but the weekend periods bring much colder temps again with cold front coming through late Friday night into Saturday. Have a rather high temperature spread across the area Saturday and timing of best cold air advection varies so confidence on specifics is low. Limited mixing in 850mb temps around -8 C brings an even colder Sunday. Final few periods of this forecast bring increasing precipitation chances. There is fairly good operational and ensemble agreement in the western upper ridge redeveloping off the coast for a more zonal to even southwest flow taking shape early in the week. Resulting deep isentropic lift should be able to saturate enough of the column for precip chances as early as late Sunday night but with greater chances Monday into Monday night. Precip type looking more challenging than most normal long-range forecasts with questions on depth of moisture to produce ice in the cloud and the potential for an above-freezing layer to develop under still cold near-surface conditions. && .AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon) Issued at 1115 AM CST WED FEB 11 2015 For the 18z TAFs, MVFR cigs will continue to scatter out this morning with breezy northerly winds persisting through late afternoon. While there will be a brief break in the wind gusts this evening, expect winds to become gusty once again near KTOP/KFOE early Thursday morning with another passing wave before diminishing by late morning. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...65 AVIATION...Johnson/ACH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
541 AM CST Wed Feb 11 2015 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 325 AM CST WED FEB 11 2015 Next in a series of cold fronts making its way southward toward the CWA at this hour. Increasing northerly winds and stratus are expected Eastern Kansas through the morning hours. Strong shortwave also noted over southern Colorado, streaming stratus to the east over Western Kansas, however energy dropping into the back of this system should drive this southward through the day today and leave little impact over our area. Cold air advection continues through the day today. This combined with stratus early should hold high temperatures only in the 30s to near 40 this afternoon, however northerly winds will leave it feeling like highs in the 20s to low 30s. NAM is more aggressive with keeping clouds over the area while HRRR and GFS/EC indicate subsidence and clearing for at least a portion of the day today. Evening hours bring a break in the winds and the clouds, however secondary cold front advances southward across the area after midnight and brings in even colder temperatures in the teens. Given north winds of 15 to 20 mph, also anticipate wind chill values near zero, and as low as -10 near in the far northeastern counties by early Thursday. .LONG TERM...(Thursday through Tuesday) Issued at 325 AM CST WED FEB 11 2015 Northwest flow aloft keeps temperatures as the main challenge into the weekend. Surface high comes in Thursday for decreasing winds, but the cold air in place will keep temps about 10F colder than today. Still appears temps may be rather steady or slowly rise late Thursday night as warm air surges back east ahead of next strong upper wave rotating around the persistent upper level trough in the east. This continues to suggest a much warmer Friday than recent days, but the weekend periods bring much colder temps again with cold front coming through late Friday night into Saturday. Have a rather high temperature spread across the area Saturday and timing of best cold air advection varies so confidence on specifics is low. Limited mixing in 850mb temps around -8 C brings an even colder Sunday. Final few periods of this forecast bring increasing precipitation chances. There is fairly good operational and ensemble agreement in the western upper ridge redeveloping off the coast for a more zonal to even southwest flow taking shape early in the week. Resulting deep isentropic lift should be able to saturate enough of the column for precip chances as early as late Sunday night but with greater chances Monday into Monday night. Precip type looking more challenging than most normal long-range forecasts with questions on depth of moisture to produce ice in the cloud and the potential for an above-freezing layer to develop under still cold near-surface conditions. && .AVIATION...(For the 12Z TAFs through 12Z Thursday Morning) Issued at 539 AM CST WED FEB 11 2015 MVFR cigs continue for the morning and potentially into the afternoon hours at all TAF sites, although some guidance suggesting deck could become scattered after only a few hours. Breezy northerly winds continue today, take a break late afternoon into the evening hours, then another front increases winds again toward end of the TAF period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...65 AVIATION...67
AREA FORECAST DISCUSSION
NWS GOODLAND KS
438 AM MST WED FEB 11 2015 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 246 AM MST WED FEB 11 2015 UPPER FLOW WILL BE NORTHWEST THROUGH FRIDAY NIGHT WITH A AMPLIFIED RIDGE OVER THE WESTERN CONUS. SURFACE HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS TODAY AND TONIGHT. A TROUGH WILL MOVE INTO EASTERN COLORADO THURSDAY/THURSDAY NIGHT AS HIGH PRESSURE SHIFTS EAST. HIGH PRESSURE WILL MOVE INTO THE REGION BEHIND THE EXITING SURFACE TROUGH FRIDAY/FRIDAY NIGHT. SUBSIDENCE WILL FOLLOW THE EXITING SHORTWAVE THIS MORNING AND CONTINUE THROUGH TONIGHT. A WEAK SHORTWAVE IS NOTED IN THE FLOW ON THURSDAY BUT MOISTURE IS WELL TO THE EAST OF THE FA SO THAT PRECIPITATION SHOULD BE UNLIKELY. SUBSIDENCE FOLLOWS THE EXITING SHORTWAVE THURSDAY NIGHT AND CONTINUES THROUGH FRIDAY NIGHT. AS A RESULT, ALL PERIODS WILL BE DRY WITH NIL POPS. NAM BOUNDARY LAYER RH INCREASES TO 90 PERCENT AS THE COLD FRONT MOVES INTO THE FA THIS MORNING. THE HRRR INDICATES CEILINGS OF AROUND 1000FT. THE LOWER CEILINGS WILL MOVE OUT OF THE SOUTHERN FA BY 17Z ACCORDING TO THE HRRR. 850 TEMPERATURES INDICATE SEASONABLE TEMPERATURES TODAY IN THE MID 40S AND THEN WARMING UP TO THE LOWER 60S IN EASTERN COLORADO THURSDAY WITH MID 50S IN NORTHWEST KANSAS. MAX TEMPERATURES FRIDAY SHOULD RISE TO NEAR 60. MIN TEMPERATURES SHOULD COOL TO THE LOWER TO MID 20S TONIGHT AND THEN MODERATE TO THE LOWER 30S THURSDAY AND FRIDAY NIGHTS. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 246 AM MST WED FEB 11 2015 SATURDAY THROUGH TUESDAY WILL SEE TEMPERATURES RETURNING TO MORE NORMAL VALUES AS A COOLER AIR MASS MOVES OVER THE AREA BEGINNING SATURDAY...AS WELL AS A CHANCE FOR PRECIPITATION EARLY NEXT WEEK. OVER THE WEEKEND THE UPPER LEVEL RIDGE THAT HAS BEEN SITUATED OVER THE GREAT BASIN WILL BE PUSHED BACK WEST AS A STRONGER UPPER LEVEL TROUGH MOVES SOUTHEAST OUT OF CANADA. THE TROUGH WILL DEEPEN AS IT MOVES SOUTHEAST ACROSS THE CONUS. AS IT DOES SO THE UPPER LEVEL FLOW WILL RESEMBLE MORE OF A SPLIT FLOW SETUP...PRIOR TO THE TROUGH REACHING THE HIGH PLAINS. IF THIS PATTERN DOES DEVELOP THERE WILL BE VERY LITTLE CHANCE FOR PRECIPITATION MONDAY NIGHT DUE TO THE UPPER LEVEL FORCING GOING AROUND THE AREA. HOWEVER WILL LEAVE IN THE CONSENSUS OF MINIMAL CHANCES FOR PRECIPITATION AS THE TROUGH MOVES THROUGH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 431 AM MST WED FEB 11 2015 STRATUS CIGS WILL CONTINUE AT KGLD AND KMCK UNTIL AROUND 16Z AND THEN MOVE OUT PRDUCING VFR CONDITIONS. WINDS WILL BE BREEZY TODAY BEHIND THE COLD FRONT. WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT AS ANOTHER BATCH OF CLOUDS MOVE THROUGH WITH VFR CONDITIONS PERSISTING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...JTL AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
252 AM MST WED FEB 11 2015 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 246 AM MST WED FEB 11 2015 UPPER FLOW WILL BE NORTHWEST THROUGH FRIDAY NIGHT WITH A AMPLIFIED RIDGE OVER THE WESTERN CONUS. SURFACE HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS TODAY AND TONIGHT. A TROUGH WILL MOVE INTO EASTERN COLORADO THURSDAY/THURSDAY NIGHT AS HIGH PRESSURE SHIFTS EAST. HIGH PRESSURE WILL MOVE INTO THE REGION BEHIND THE EXITING SURFACE TROUGH FRIDAY/FRIDAY NIGHT. SUBSIDENCE WILL FOLLOW THE EXITING SHORTWAVE THIS MORNING AND CONTINUE THROUGH TONIGHT. A WEAK SHORTWAVE IS NOTED IN THE FLOW ON THURSDAY BUT MOISTURE IS WELL TO THE EAST OF THE FA SO THAT PRECIPITATION SHOULD BE UNLIKELY. SUBSIDENCE FOLLOWS THE EXITING SHORTWAVE THURSDAY NIGHT AND CONTINUES THROUGH FRIDAY NIGHT. AS A RESULT, ALL PERIODS WILL BE DRY WITH NIL POPS. NAM BOUNDARY LAYER RH INCREASES TO 90 PERCENT AS THE COLD FRONT MOVES INTO THE FA THIS MORNING. THE HRRR INDICATES CEILINGS OF AROUND 1000FT. THE LOWER CEILINGS WILL MOVE OUT OF THE SOUTHERN FA BY 17Z ACCORDING TO THE HRRR. 850 TEMPERATURES INDICATE SEASONABLE TEMPERATURES TODAY IN THE MID 40S AND THEN WARMING UP TO THE LOWER 60S IN EASTERN COLORADO THURSDAY WITH MID 50S IN NORTHWEST KANSAS. MAX TEMPERATURES FRIDAY SHOULD RISE TO NEAR 60. MIN TEMPERATURES SHOULD COOL TO THE LOWER TO MID 20S TONIGHT AND THEN MODERATE TO THE LOWER 30S THURSDAY AND FRIDAY NIGHTS. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 246 AM MST WED FEB 11 2015 SATURDAY THROUGH TUESDAY WILL SEE TEMPERATURES RETURNING TO MORE NORMAL VALUES AS A COOLER AIR MASS MOVES OVER THE AREA BEGINNING SATURDAY...AS WELL AS A CHANCE FOR PRECIPITATION EARLY NEXT WEEK. OVER THE WEEKEND THE UPPER LEVEL RIDGE THAT HAS BEEN SITUATED OVER THE GREAT BASIN WILL BE PUSHED BACK WEST AS A STRONGER UPPER LEVEL TROUGH MOVES SOUTHEAST OUT OF CANADA. THE TROUGH WILL DEEPEN AS IT MOVES SOUTHEAST ACROSS THE CONUS. AS IT DOES SO THE UPPER LEVEL FLOW WILL RESEMBLE MORE OF A SPLIT FLOW SETUP...PRIOR TO THE TROUGH REACHING THE HIGH PLAINS. IF THIS PATTERN DOES DEVELOP THERE WILL BE VERY LITTLE CHANCE FOR PRECIPITATION MONDAY NIGHT DUE TO THE UPPER LEVEL FORCING GOING AROUND THE AREA. HOWEVER WILL LEAVE IN THE CONSENSUS OF MINIMAL CHANCES FOR PRECIPITATION AS THE TROUGH MOVES THROUGH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1041 PM MST TUE FEB 10 2015 A COLD FRONT IS IN THE PROCESS OF MOVING THROUGH THE FORECAST AREA. BEHIND THE FRONT OCCASIONAL MVFR CEILINGS CAN BE EXPECTED UNTIL NEAR 13Z FOR BOTH TAF SITES. AFTER THAT...MVFR CONDITIONS ARE EXPECTED FOR THE REST OF THE PERIOD. AFTER 13Z...NORTH WINDS WILL STRENGTHEN AND PRODUCE GUSTS TO NEAR 25 KNOTS UNTIL MID AFTERNOON WHEN THEY BEGIN TO DECREASE. LATE IN THE AFTERNOON INTO THE EARLY AFTERNOON...THE WINDS WILL BECOME LIGHT AND VARIABLE AND SLOW SHIFT TO A SOUTHWEST DIRECTION. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FS LONG TERM...JTL AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
326 AM CST Wed Feb 11 2015 .SHORT TERM...(Today and Tonight) Issued at 325 AM CST WED FEB 11 2015 Next in a series of cold fronts making its way southward toward the CWA at this hour. Increasing northerly winds and stratus are expected Eastern Kansas through the morning hours. Strong shortwave also noted over southern Colorado, streaming stratus to the east over Western Kansas, however energy dropping into the back of this system should drive this southward through the day today and leave little impact over our area. Cold air advection continues through the day today. This combined with stratus early should hold high temperatures only in the 30s to near 40 this afternoon, however northerly winds will leave it feeling like highs in the 20s to low 30s. NAM is more aggressive with keeping clouds over the area while HRRR and GFS/EC indicate subsidence and clearing for at least a portion of the day today. Evening hours bring a break in the winds and the clouds, however secondary cold front advances southward across the area after midnight and brings in even colder temperatures in the teens. Given north winds of 15 to 20 mph, also anticipate wind chill values near zero, and as low as -10 near in the far northeastern counties by early Thursday. .LONG TERM...(Thursday through Tuesday) Issued at 325 AM CST WED FEB 11 2015 Northwest flow aloft keeps temperatures as the main challenge into the weekend. Surface high comes in Thursday for decreasing winds, but the cold air in place will keep temps about 10F colder than today. Still appears temps may be rather steady or slowly rise late Thursday night as warm air surges back east ahead of next strong upper wave rotating around the persistent upper level trough in the east. This continues to suggest a much warmer Friday than recent days, but the weekend periods bring much colder temps again with cold front coming through late Friday night into Saturday. Have a rather high temperature spread across the area Saturday and timing of best cold air advection varies so confidence on specifics is low. Limited mixing in 850mb temps around -8 C brings an even colder Sunday. Final few periods of this forecast bring increasing precipitation chances. There is fairly good operational and ensemble agreement in the western upper ridge redeveloping off the coast for a more zonal to even southwest flow taking shape early in the week. Resulting deep isentropic lift should be able to saturate enough of the column for precip chances as early as late Sunday night but with greater chances Monday into Monday night. Precip type looking more challenging than most normal long-range forecasts with questions on depth of moisture to produce ice in the cloud and the potential for an above-freezing layer to develop under still cold near-surface conditions. && .AVIATION...(For the 06Z TAFs through 06Z Wednesday Night) Issued at 1116 PM CST TUE FEB 10 2015 Latest observational trends upstream near the cold front suggest a later arrival in gusty winds than previous forecast. VFR prevails with an increase in mid level clouds as light northwest winds gradually increase above 10 kts behind the boundary between 10 and 12Z. MVFR stratus accompanies the stronger winds mid morning onward. Widespread wind gusts to 26 kts are expected shortly after sunrise through the afternoon. Still some uncertainty from guidance on how quickly deck scatters to VFR...occurring most likely during the mid afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...65 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1237 PM EST WED FEB 11 2015 .SYNOPSIS... A LATE DAY COLD FRONT WILL BEGIN THE TRANSITION TO FRIGID TEMPERATURES WHICH WILL PERSIST INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN CHANGE TODAY WAS TO ADJUST TEMPS JUST A FEW DEGREES...UPWARD IN THE FAR NORTHERN ZONES AND DOWNWARD IN THE REMAINING ZONES. LINGERING CLOUDS HAVE SUPPRESSED MIXING SUFFICIENTLY TO THROW A WRENCH IN THE TYPICAL DIURNAL HEATING CURVE. GIVEN THAT THE NOCTURNAL INVERSION HAS MOSTLY MIXED OUT...IT WILL TAKE THE REST OF THE AFTERNOON TO MIX OUT THE REMAINING FEW HUNDRED FEET TO ACHIEVE UPPER 30S. PREVIOUS DISCUSSION FOLLOWS... OVERALL...A SOFT DAY IS ANTICIPATED FOR THE UPPER OHIO REGION AS A STRONG SHORTWAVE TROUGH...WITH AXIS OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING...PROGRESSES OVER THE GREAT LAKES. WARM ADVECTION IN ADVANCE OF THAT SYSTEM SHOULD SUPPORT HIGHS NEAR THE MID FEBRUARY AVERAGES DESPITE A CLOUD INCREASE WITH THE MID LEVEL MOISTURE SURGE. THE TEMPERATURE FORECAST WAS TWEAKED USING THE LATEST SREF...NAM...AND RAP GUIDANCE TRENDS...BUT CHANGES WERE MINIMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE ACTUAL COLD FRONT PASSAGE IS NOT EXPECTED TO BE DRAMATIC AS FAR AS PRECIPITATION IS CONCERNED WITH THE LOW CENTER PROJECTED TOWARD NEW YORK AND A MID LEVEL DRY SLOT RAPIDLY ENCROACHING INTO UPPER OHIO VALLEY AIRSPACE. HOWEVER...THURSDAY TEMPERATURES WILL BE ON THE DECLINE...WITH SNOW SHOWER COVERAGE INCREASING UNDER A FRIGID MID LEVEL THERMAL TROUGH. THE STEEPENING LOW LEVEL LAPSE RATES AND A SHALLOW DENDRITIC GROWTH ZONE WILL RESULT IN INCREASED CONVECTIVE SNOW SHOWER ACCUMULATION POTENTIAL ON THURSDAY...ESPECIALLY IN THE USUAL UPSLOPE AREAS OF THE RIDGES AND ZONES IN LEE OF THE LAKES. NOT MUCH CHANGE WAS NEEDED FOR THE ONGOING 1-2 FORECAST WITH 2-4 INCHES ON THE RIDGES. EASTWARD PROGRESS OF THE MAIN MID LEVEL COLD POOL...I.E. FALLING INVERSION LEVELS WITH DRY ADVECTION SHOULD RAPIDLY LIMIT ADDITIONAL ACCUMULATION POTENTIAL ON THURSDAY NIGHT. THE COLD THURSDAY NIGHT AND FRIDAY TEMPERATURE FORECAST WAS NOT DISPUTED MUCH BY INCOMING GUIDANCE AS A HIGH AMPLITUDE EASTERN U.S. UPPER TROUGH AXIS IS DEVELOPED SLOWLY EASTWARD...HENCE CHANGES WERE MINIMAL ALTHOUGH THE WIND WAS REDONE USING NAM AND GFS GRIDS. WIND CHILL INDICES STILL ARE PROJECTED INTO THE ADVISORY RANGE OF -10 TO -20C...SO A HAZARDOUS WEATHER OUTLOOK MENTION WILL BE MAINTAINED WITH A MENTION OF SNOW ACCUMULATION IN THE RIDGES...WHERE THE BETTER CHANCE FOR AN ADVISORY IS ON THURSDAY. NO REPRIEVE IS INDICATED THIS WEEKEND AS THE ECMWF AND GFS SOLUTIONS ARE OF A STRONG SHORTWAVE ROTATING SOUTHWARD OUT OF THE HUDSON BAY AREA. THAT SYSTEM AS MODELED WOULD RECARVE THE UPPER TROUGH OVER THE EASTERN U.S. CURRENT PROJECTIONS ARE THAT THE MID LEVEL LOW CENTER WILL REMAIN NORTH OF THE AREA...THUS KEEPING THE SNOW FAVORABLE TROWAL...FRONTOGENESIS REGIONS AT BAY. NEVERTHELESS...A COLD COLUMN WILL MAINTAIN FRIGID TEMPERATURES AND HIGH SNOW RATIO PARAMETERS. PRECIPITATION PROBABILITIES WERE BUMPED UP ON SATURDAY IN ACCORDANCE WITH THESE TRENDS AND GENERALLY ARE IN LINE WITH GFS GRIDS. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AS UPPER LOW MOVES EAST OF THE REGION...SNOW SHOWERS WILL WIND DOWN SATURDAY NIGHT WITH SOME LAKE EFFECT CONTINUING INTO SUNDAY. WITH THE SURFACE HIGH THEN BUILDING INTO THE REGION SUNDAY NIGHT...WINDS WILL DIMINISH AND ALL SNOW WILL COME TO AN END. SUNDAY AND SUNDAY NIGHT APPEARS TO BE THE COLDEST 24 HOUR PERIOD OF THE WINTER SO FAR...WITH HIGHS IN THE SINGLE DIGITS AND LOWS RANGING FROM 5 ABOVE TO 10 BELOW. WINDS MAY GO LIGHT WITH THE HIGH PRESSURE CENTER OVERHEAD...WHICH COULD LIMIT JUST HOW LOW WIND CHILL VALUES GO. LOW MOVES NORTHEAST FROM THE SOUTHERN PLAINS MONDAY NIGHT INTO TUESDAY. EVEN WITH WARMER TEMPERATURES MOVING IN BY MONDAY NIGHT...TEMPERATURES WILL REMAIN COLD ENOUGH THAT ALL PRECIPITATION SHOULD FALL AS SNOW WITH THAT SYSTEM. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... SOME LOW CLOUDS CONTINUE TO PERSIST IN AREAS ALONG/NEAR THE RIDGES...AT LOCATIONS LIKE MGW...IDI...AND DUJ. STILL EXPECT THESE TO MOSTLY BREAK UP BY 20Z. OTHERWISE...VFR EXPECTED INTO THIS EVENING WITH ONLY MID LEVEL CLOUDS. CIGS WILL DROP BEHIND A COLD FRONT TONIGHT...WITH MVFR CONDITIONS FORECAST IN SCATTERED TO NUMEROUS SHSN. SPOTTY IFR VSBYS ALSO POSSIBLE TONIGHT BUT CONFIDENCE IN COVERAGE/TIMING OF THIS NOT ENOUGH TO INCLUDE YET. BETTER CHANCE OF IFR AND EVENTUAL LIFR RESTRICTIONS COMES AFTER 12Z THURSDAY AS THE TRUE ARCTIC AIR ARRIVES. EXPECTING A PERIOD OF SNOW SQUALLS TO ACCOMPANY THIS COLD SHOT...WITH LOCATIONS ALONG THE RIDGES POTENTIALLY GETTING HIT HARD...ESPECIALLY IN MD/WV. GUSTY NW WINDS WILL ACCOMPANY THIS ACTIVITY. OUTLOOK.../THURSDAY THROUGH SUNDAY/... RESTRICTIONS SHOULD DIMINISH THURSDAY NIGHT AS THE SYSTEM MOVES EAST. PERIODIC RESTRICTIONS ARE THEN LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH A SERIES OF DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1203 PM EST WED FEB 11 2015 .SYNOPSIS... A LATE DAY COLD FRONT WILL BEGIN THE TRANSITION TO FRIGID TEMPERATURES WHICH WILL PERSIST INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN CHANGE TODAY WAS TO ADJUST TEMPS JUST A FEW DEGREES...UPWARD IN THE FAR NORTHERN ZONES AND DOWNWARD IN THE REMAINING ZONES. LINGERING CLOUDS HAVE SUPPRESSED MIXING SUFFICIENTLY TO THROW A WRENCH IN THE TYPICAL DIURNAL HEATING CURVE. GIVEN THAT THE NOCTURNAL INVERSION HAS MOSTLY MIXED OUT...IT WILL TAKE THE REST OF THE AFTERNOON TO MIX OUT THE REMAINING FEW HUNDRED FEET TO ACHIEVE UPPER 30S. PREVIOUS DISCUSSION FOLLOWS... OVERALL...A SOFT DAY IS ANTICIPATED FOR THE UPPER OHIO REGION AS A STRONG SHORTWAVE TROUGH...WITH AXIS OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING...PROGRESSES OVER THE GREAT LAKES. WARM ADVECTION IN ADVANCE OF THAT SYSTEM SHOULD SUPPORT HIGHS NEAR THE MID FEBRUARY AVERAGES DESPITE A CLOUD INCREASE WITH THE MID LEVEL MOISTURE SURGE. THE TEMPERATURE FORECAST WAS TWEAKED USING THE LATEST SREF...NAM...AND RAP GUIDANCE TRENDS...BUT CHANGES WERE MINIMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE ACTUAL COLD FRONT PASSAGE IS NOT EXPECTED TO BE DRAMATIC AS FAR AS PRECIPITATION IS CONCERNED WITH THE LOW CENTER PROJECTED TOWARD NEW YORK AND A MID LEVEL DRY SLOT RAPIDLY ENCROACHING INTO UPPER OHIO VALLEY AIRSPACE. HOWEVER...THURSDAY TEMPERATURES WILL BE ON THE DECLINE...WITH SNOW SHOWER COVERAGE INCREASING UNDER A FRIGID MID LEVEL THERMAL TROUGH. THE STEEPENING LOW LEVEL LAPSE RATES AND A SHALLOW DENDRITIC GROWTH ZONE WILL RESULT IN INCREASED CONVECTIVE SNOW SHOWER ACCUMULATION POTENTIAL ON THURSDAY...ESPECIALLY IN THE USUAL UPSLOPE AREAS OF THE RIDGES AND ZONES IN LEE OF THE LAKES. NOT MUCH CHANGE WAS NEEDED FOR THE ONGOING 1-2 FORECAST WITH 2-4 INCHES ON THE RIDGES. EASTWARD PROGRESS OF THE MAIN MID LEVEL COLD POOL...I.E. FALLING INVERSION LEVELS WITH DRY ADVECTION SHOULD RAPIDLY LIMIT ADDITIONAL ACCUMULATION POTENTIAL ON THURSDAY NIGHT. THE COLD THURSDAY NIGHT AND FRIDAY TEMPERATURE FORECAST WAS NOT DISPUTED MUCH BY INCOMING GUIDANCE AS A HIGH AMPLITUDE EASTERN U.S. UPPER TROUGH AXIS IS DEVELOPED SLOWLY EASTWARD...HENCE CHANGES WERE MINIMAL ALTHOUGH THE WIND WAS REDONE USING NAM AND GFS GRIDS. WIND CHILL INDICES STILL ARE PROJECTED INTO THE ADVISORY RANGE OF -10 TO -20C...SO A HAZARDOUS WEATHER OUTLOOK MENTION WILL BE MAINTAINED WITH A MENTION OF SNOW ACCUMULATION IN THE RIDGES...WHERE THE BETTER CHANCE FOR AN ADVISORY IS ON THURSDAY. NO REPRIEVE IS INDICATED THIS WEEKEND AS THE ECMWF AND GFS SOLUTIONS ARE OF A STRONG SHORTWAVE ROTATING SOUTHWARD OUT OF THE HUDSON BAY AREA. THAT SYSTEM AS MODELED WOULD RECARVE THE UPPER TROUGH OVER THE EASTERN U.S. CURRENT PROJECTIONS ARE THAT THE MID LEVEL LOW CENTER WILL REMAIN NORTH OF THE AREA...THUS KEEPING THE SNOW FAVORABLE TROWAL...FRONTOGENESIS REGIONS AT BAY. NEVERTHELESS...A COLD COLUMN WILL MAINTAIN FRIGID TEMPERATURES AND HIGH SNOW RATIO PARAMETERS. PRECIPITATION PROBABILITIES WERE BUMPED UP ON SATURDAY IN ACCORDANCE WITH THESE TRENDS AND GENERALLY ARE IN LINE WITH GFS GRIDS. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AS UPPER LOW MOVES EAST OF THE REGION...SNOW SHOWERS WILL WIND DOWN SATURDAY NIGHT WITH SOME LAKE EFFECT CONTINUING INTO SUNDAY. WITH THE SURFACE HIGH THEN BUILDING INTO THE REGION SUNDAY NIGHT...WINDS WILL DIMINISH AND ALL SNOW WILL COME TO AN END. SUNDAY AND SUNDAY NIGHT APPEARS TO BE THE COLDEST 24 HOUR PERIOD OF THE WINTER SO FAR...WITH HIGHS IN THE SINGLE DIGITS AND LOWS RANGING FROM 5 ABOVE TO 10 BELOW. WINDS MAY GO LIGHT WITH THE HIGH PRESSURE CENTER OVERHEAD...WHICH COULD LIMIT JUST HOW LOW WIND CHILL VALUES GO. LOW MOVES NORTHEAST FROM THE SOUTHERN PLAINS MONDAY NIGHT INTO TUESDAY. EVEN WITH WARMER TEMPERATURES MOVING IN BY MONDAY NIGHT...TEMPERATURES WILL REMAIN COLD ENOUGH THAT ALL PRECIPITATION SHOULD FALL AS SNOW WITH THAT SYSTEM. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... STRATUS CONTINUES TO PLAGUE FKL/DUJ/LBE...WITH FKL RIGHT ON THE BORDER BETWEEN CLEAR SKIES AND NEAR LIFR CEILINGS. MVFR FOG AT ZZV AND STRATUS AT FKL/DUJ/LBE SHOULD DIMINISH IN COVERAGE BY MID MORNING...ALTHOUGH FKL/DUJ COULD POTENTIALLY STAY IN THE STRATUS THROUGH THE TAF PERIOD. COLD FRONT PUSHES THROUGH THE REGION THIS EVENING...BRINGING MVFR/IFR RESTRICTIONS AND A SHIFT IN THE WINDS. STILL UNSURE OF HOW LOW VISIBILITIES WILL DROP WITH SCATTERED SNOW SHOWERS...BUT HAVE AT LEAST BROUGHT A MENTION OF SNOW INTO ALL TERMINALS. SNOW WILL NOT BECOME MORE WIDESPREAD UNTIL THURSDAY...WITH IFR SNOW MENTIONED IN THE 30 HOUR PORTION OF THE PITTSBURGH TAF. OUTLOOK.../THURSDAY THROUGH SUNDAY/... RESTRICTIONS SHOULD DIMINISH THURSDAY NIGHT AS THE SYSTEM MOVES EAST. PERIODIC RESTRICTIONS ARE THEN LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH A SERIES OF DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ UPDATE...KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
634 AM EST WED FEB 11 2015 .SYNOPSIS... A LATE DAY COLD FRONT WILL BEGIN THE TRANSITION TO FRIGID TEMPERATURES WHICH WILL PERSIST INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... OVERALL...A SOFT DAY IS ANTICIPATED FOR THE UPPER OHIO REGION AS A STRONG SHORTWAVE TROUGH...WITH AXIS OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING...PROGRESSES OVER THE GREAT LAKES. WARM ADVECTION IN ADVANCE OF THAT SYSTEM SHOULD SUPPORT HIGHS NEAR THE MID FEBRUARY AVERAGES DESPITE A CLOUD INCREASE WITH THE MID LEVEL MOISTURE SURGE. THE TEMPERATURE FORECAST WAS TWEAKED USING THE LATEST SREF...NAM...AND RAP GUIDANCE TRENDS...BUT CHANGES WERE MINIMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE ACTUAL COLD FRONT PASSAGE IS NOT EXPECTED TO BE DRAMATIC AS FAR AS PRECIPITATION IS CONCERNED WITH THE LOW CENTER PROJECTED TOWARD NEW YORK AND A MID LEVEL DRY SLOT RAPIDLY ENCROACHING INTO UPPER OHIO VALLEY AIRSPACE. HOWEVER...THURSDAY TEMPERATURES WILL BE ON THE DECLINE...WITH SNOW SHOWER COVERAGE INCREASING UNDER A FRIGID MID LEVEL THERMAL TROUGH. THE STEEPENING LOW LEVEL LAPSE RATES AND A SHALLOW DENDRITIC GROWTH ZONE WILL RESULT IN INCREASED CONVECTIVE SNOW SHOWER ACCUMULATION POTENTIAL ON THURSDAY...ESPECIALLY IN THE USUAL UPSLOPE AREAS OF THE RIDGES AND ZONES IN LEE OF THE LAKES. NOT MUCH CHANGE WAS NEEDED FOR THE ONGOING 1-2 FORECAST WITH 2-4 INCHES ON THE RIDGES. EASTWARD PROGRESS OF THE MAIN MID LEVEL COLD POOL...I.E. FALLING INVERSION LEVELS WITH DRY ADVECTION SHOULD RAPIDLY LIMIT ADDITIONAL ACCUMULATION POTENTIAL ON THURSDAY NIGHT. THE COLD THURSDAY NIGHT AND FRIDAY TEMPERATURE FORECAST WAS NOT DISPUTED MUCH BY INCOMING GUIDANCE AS A HIGH AMPLITUDE EASTERN U.S. UPPER TROUGH AXIS IS DEVELOPED SLOWLY EASTWARD...HENCE CHANGES WERE MINIMAL ALTHOUGH THE WIND WAS REDONE USING NAM AND GFS GRIDS. WIND CHILL INDICES STILL ARE PROJECTED INTO THE ADVISORY RANGE OF -10 TO -20C...SO A HAZARDOUS WEATHER OUTLOOK MENTION WILL BE MAINTAINED WITH A MENTION OF SNOW ACCUMULATION IN THE RIDGES...WHERE THE BETTER CHANCE FOR AN ADVISORY IS ON THURSDAY. NO REPRIEVE IS INDICATED THIS WEEKEND AS THE ECMWF AND GFS SOLUTIONS ARE OF A STRONG SHORTWAVE ROTATING SOUTHWARD OUT OF THE HUDSON BAY AREA. THAT SYSTEM AS MODELED WOULD RECARVE THE UPPER TROUGH OVER THE EASTERN U.S. CURRENT PROJECTIONS ARE THAT THE MID LEVEL LOW CENTER WILL REMAIN NORTH OF THE AREA...THUS KEEPING THE SNOW FAVORABLE TROWAL...FRONTOGENESIS REGIONS AT BAY. NEVERTHELESS...A COLD COLUMN WILL MAINTAIN FRIGID TEMPERATURES AND HIGH SNOW RATIO PARAMETERS. PRECIPITATION PROBABILITIES WERE BUMPED UP ON SATURDAY IN ACCORDANCE WITH THESE TRENDS AND GENERALLY ARE IN LINE WITH GFS GRIDS. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AS UPPER LOW MOVES EAST OF THE REGION...SNOW SHOWERS WILL WIND DOWN SATURDAY NIGHT WITH SOME LAKE EFFECT CONTINUING INTO SUNDAY. WITH THE SURFACE HIGH THEN BUILDING INTO THE REGION SUNDAY NIGHT...WINDS WILL DIMINISH AND ALL SNOW WILL COME TO AN END. SUNDAY AND SUNDAY NIGHT APPEARS TO BE THE COLDEST 24 HOUR PERIOD OF THE WINTER SO FAR...WITH HIGHS IN THE SINGLE DIGITS AND LOWS RANGING FROM 5 ABOVE TO 10 BELOW. WINDS MAY GO LIGHT WITH THE HIGH PRESSURE CENTER OVERHEAD...WHICH COULD LIMIT JUST HOW LOW WIND CHILL VALUES GO. LOW MOVES NORTHEAST FROM THE SOUTHERN PLAINS MONDAY NIGHT INTO TUESDAY. EVEN WITH WARMER TEMPERATURES MOVING IN BY MONDAY NIGHT...TEMPERATURES WILL REMAIN COLD ENOUGH THAT ALL PRECIPITATION SHOULD FALL AS SNOW WITH THAT SYSTEM. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... STRATUS CONTINUES TO PLAGUE FKL/DUJ/LBE...WITH FKL RIGHT ON THE BORDER BETWEEN CLEAR SKIES AND NEAR LIFR CEILINGS. MVFR FOG AT ZZV AND STRATUS AT FKL/DUJ/LBE SHOULD DIMINISH IN COVERAGE BY MID MORNING...ALTHOUGH FKL/DUJ COULD POTENTIALLY STAY IN THE STRATUS THROUGH THE TAF PERIOD. COLD FRONT PUSHES THROUGH THE REGION THIS EVENING...BRINGING MVFR/IFR RESTRICTIONS AND A SHIFT IN THE WINDS. STILL UNSURE OF HOW LOW VISIBILITIES WILL DROP WITH SCATTERED SNOW SHOWERS...BUT HAVE AT LEAST BROUGHT A MENTION OF SNOW INTO ALL TERMINALS. SNOW WILL NOT BECOME MORE WIDESPREAD UNTIL THURSDAY...WITH IFR SNOW MENTIONED IN THE 30 HOUR PORTION OF THE PITTSBURGH TAF. OUTLOOK.../THURSDAY THROUGH SUNDAY/... RESTRICTIONS SHOULD DIMINISH THURSDAY NIGHT AS THE SYSTEM MOVES EAST. PERIODIC RESTRICTIONS ARE THEN LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH A SERIES OF DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
316 AM EST WED FEB 11 2015 .SYNOPSIS... A LATE DAY COLD FRONT WILL BEGIN THE TRANSITION TO FRIGID TEMPERATURES WHICH WILL PERSIST INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... OVERALL...A SOFT DAY IS ANTICIPATED FOR THE UPPER OHIO REGION AS A STRONG SHORTWAVE TROUGH...WITH AXIS OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING...PROGRESSES OVER THE GREAT LAKES. WARM ADVECTION IN ADVANCE OF THAT SYSTEM SHOULD SUPPORT HIGHS NEAR THE MID FEBRUARY AVERAGES DESPITE A CLOUD INCREASE WITH THE MID LEVEL MOISTURE SURGE. THE TEMPERATURE FORECAST WAS TWEAKED USING THE LATEST SREF...NAM...AND RAP GUIDANCE TRENDS...BUT CHANGES WERE MINIMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... THE ACTUAL COLD FRONT PASSAGE IS NOT EXPECTED TO BE DRAMATIC AS FAR AS PRECIPITATION IS CONCERNED WITH THE LOW CENTER PROJECTED TOWARD NEW YORK AND A MID LEVEL DRY SLOT RAPIDLY ENCROACHING INTO UPPER OHIO VALLEY AIRSPACE. HOWEVER...THURSDAY TEMPERATURES WILL BE ON THE DECLINE...WITH SNOW SHOWER COVERAGE INCREASING UNDER A FRIGID MID LEVEL THERMAL TROUGH. THE STEEPENING LOW LEVEL LAPSE RATES AND A SHALLOW DENDRITIC GROWTH ZONE WILL RESULT IN INCREASED CONVECTIVE SNOW SHOWER ACCUMULATION POTENTIAL ON THURSDAY...ESPECIALLY IN THE USUAL UPSLOPE AREAS OF THE RIDGES AND ZONES IN LEE OF THE LAKES. NOT MUCH CHANGE WAS NEEDED FOR THE ONGOING 1-2 FORECAST WITH 2-4 INCHES ON THE RIDGES. EASTWARD PROGRESS OF THE MAIN MID LEVEL COLD POOL...I.E. FALLING INVERSION LEVELS WITH DRY ADVECTION SHOULD RAPIDLY LIMIT ADDITIONAL ACCUMULATION POTENTIAL ON THURSDAY NIGHT. THE COLD THURSDAY NIGHT AND FRIDAY TEMPERATURE FORECAST WAS NOT DISPUTED MUCH BY INCOMING GUIDANCE AS A HIGH AMPLITUDE EASTERN U.S. UPPER TROUGH AXIS IS DEVELOPED SLOWLY EASTWARD...HENCE CHANGES WERE MINIMAL ALTHOUGH THE WIND WAS REDONE USING NAM AND GFS GRIDS. WIND CHILL INDICES STILL ARE PROJECTED INTO THE ADVISORY RANGE OF -10 TO -20C...SO A HAZARDOUS WEATHER OUTLOOK MENTION WILL BE MAINTAINED WITH A MENTION OF SNOW ACCUMULATION IN THE RIDGES...WHERE THE BETTER CHANCE FOR AN ADVISORY IS ON THURSDAY. NO REPRIEVE IS INDICATED THIS WEEKEND AS THE ECMWF AND GFS SOLUTIONS ARE OF A STRONG SHORTWAVE ROTATING SOUTHWARD OUT OF THE HUDSON BAY AREA. THAT SYSTEM AS MODELED WOULD RECARVE THE UPPER TROUGH OVER THE EASTERN U.S. CURRENT PROJECTIONS ARE THAT THE MID LEVEL LOW CENTER WILL REMAIN NORTH OF THE AREA...THUS KEEPING THE SNOW FAVORABLE TROWAL...FRONTOGENESIS REGIONS AT BAY. NEVERTHELESS...A COLD COLUMN WILL MAINTAIN FRIGID TEMPERATURES AND HIGH SNOW RATIO PARAMETERS. PRECIPITATION PROBABILTIES WERE BUMPED UP ON SATURDAY IN ACCORDANCE WITH THESE TRENDS AND GENERALLY ARE IN LINE WITH GFS GRIDS. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AS UPPER LOW MOVES EAST OF THE REGION...SNOW SHOWERS WILL WIND DOWN SATURDAY NIGHT WITH SOME LAKE EFFECT CONTINUING INTO SUNDAY. WITH THE SURFACE HIGH THEN BUILDING INTO THE REGION SUNDAY NIGHT...WINDS WILL DIMINISH AND ALL SNOW WILL COME TO AN END. SUNDAY AND SUNDAY NIGHT APPEARS TO BE THE COLDEST 24 HOUR PERIOD OF THE WINTER SO FAR...WITH HIGHS IN THE SINGLE DIGITS AND LOWS RANGING FROM 5 ABOVE TO 10 BELOW. WINDS MAY GO LIGHT WITH THE HIGH PRESSURE CENTER OVERHEAD...WHICH COULD LIMIT JUST HOW LOW WIND CHILL VALUES GO. LOW MOVES NORTHEAST FROM THE SOUTHERN PLAINS MONDAY NIGHT INTO TUESDAY. EVEN WITH WARMER TEMPERATURES MOVING IN BY MONDAY NIGHT...TEMPERATURES WILL REMAIN COLD ENOUGH THAT ALL PRECIPITATION SHOULD FALL AS SNOW WITH THAT SYSTEM. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... STRATUS WILL CONTINUE OVERNIGHT AT FKL/DUJ/LBE...WITH THE WESTERN EDGE OF STRATUS CURRENTLY HOVERING JUST EAST OF AGC/MGW. LOW CONFIDENCE FORECAST IN WHETHER THOSE TWO TERMINALS WILL BE IMPACTED...BUT HAVE PULLED THE MENTION OF STRATUS PREVIOUSLY IN THE PIT/BVI/HLG TAFS. MVFR FOG HAS ALSO MOVED INTO ZZV...AND SHOULD PERSIST THROUGH THE NIGHT. STRATUS SHOULD DIMINISH IN COVERAGE AFTER SUNRISE...ALTHOUGH FKL/DUJ COULD POTENTIALLY STAY IN THE STRATUS THROUGH THE TAF PERIOD. HAVE GONE MORE PESSIMISTIC THAN PREVIOUS TAFS FOR THOSE TWO SITES. COLD FRONT PUSHES THROUGH THE REGION THIS EVENING...BRINGING RESTRICTIONS AND A SHIFT IN THE WINDS. STILL UNSURE OF HOW LOW VISIBILITIES WILL DROP WITH SNOW SHOWERS...BUT HAVE AT LEAST BROUGHT A MENTION OF SNOW INTO SEVERAL SITES. OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... RESTRICTIONS WILL CONTINUE INTO THURSDAY BEHIND THE COLD FRONT. PERIODIC RESTRICTIONS ARE THEN LIKELY INTO THE WEEKEND WITH A SERIES OF DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/33
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1251 AM EST WED FEB 11 2015 .SYNOPSIS... A LATE DAY COLD FRONT WILL BEGIN THE TRANSITION TO FRIGID TEMPERATURES WHICH WILL PERSIST FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TODAY/... THE POST MIDNIGHT UPDATE FEATURED ONLY MINOR ADJUSTMENTS AS STRATUS OVER NORTHERN AND EASTERN ZONES PERSISTS UNDER A SHARP INVERSION. SUBSIDENCE UNDER A BUILDING RIDGE HAS KEPT SKIES MOSTLY CLEAR ELSEWHERE. OVERALL...A SOFT DAY IS ANTICIPATED FOR THE UPPER OHIO REGION AS A STRONG SHORTWAVE TROUGH...WITH AXIS OVER THE UPPER MISSISSIPPI VALLEY THIS MORNING...PROGRESSES OVER THE GREAT LAKES. WARM ADVECTION IN ADVANCE OF THAT SYSTEM SHOULD SUPPORT HIGHS NEAR THE MID FEBRUARY AVERAGES DESPITE A CLOUD INCREASE WITH THE MID LEVEL MOISTURE SURGE. THE TEMPERATURE FORECAST WAS TWEAKED USING THE LATEST SREF...NAM...AND RAP GUIDANCE TRENDS...BUT CHANGES WERE MINIMAL. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... THE ACTUAL COLD FRONT PASSAGE IS NOT EXPECTED TO BE DRAMATIC AS FAR AS PRECIPITATION IS CONCERNED WITH THE LOW CENTER PROJECTED TOWARD NEW YORK AND A MID LEVEL DRY SLOT RAPIDLY ENCROACHING INTO UPPER OHIO VALLEY AIRSPACE. HOWEVER...THURSDAY TEMPERATURES WILL BE ON THE DECLINE...WITH SNOW SHOWER COVERAGE INCREASING UNDER A FRIGID MID LEVEL THERMAL TROUGH. THE STEEPENING LOW LEVEL LAPSE RATES AND A SHALLOW DENDRITIC GROWTH WILL RESULT IN INCREASED CONVECTIVE SNOW SHOWER ACCUMULATION POTENTIAL...ESPECIALLY IN THE USUAL UPSLOPE AREAS OF THE RIDGES AND ZONES IN LEE OF THE LAKES. NOT MUCH CHANGE WAS NEEDED FOR THE ONGOING 1-3 FORECAST WITH 2-4 INCHES ON THE RIDGES. EASTWARD PROGRESS OF THE MAIN MID LEVEL COLD POOL...I.E. FALLING INVERSION LEVELS WITH DRY ADVECTION SHOULD RAPIDLY LIMIT ADDITIONAL ACCUMULATION POTENTIAL ON THURSDAY NIGHT. THE COLD THURSDAY NIGHT AND FRIDAY TEMPERATURE FORECAST WAS NOT DISPUTED MUCH BY INCOMING GUIDANCE AS A HIGH AMPLITUDE EASTERN U.S. UPPER TROUGH DEVELOPS...HENCE CHANGES WERE MINIMAL ALTHOUGH THE WIND WAS REDONE USING NAM AND GFS GRIDS. WIND CHILL INDICES STILL ARE PROJECTED INTO THE ADVISORY RANGE OF -10 TO -20C...SO A HAZARDOUS WEATHER OUTLOOK MENTION WILL BE MAINTAINED WITH A MENTION OF SNOW ACCUMULATION IN THE RIDGES...WHERE THE BETTER CHANCE FOR AN ADVISORY IS ON THURSDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... LOW PRESSURE WITH ORIGINS IN THE ARCTIC DROPS SOUTH ACROSS THE REGION SATURDAY BRINGING A WIDESPREAD LIGHT SNOW. SNOW RATIOS FOR THIS SYSTEM WILL BE QUITE HIGH 20:1 - 30:1. A FEW INCHES APPEAR LIKELY...HOWEVER DUE TO TIMING DIFFERENCES TRENDED POPS UPWARD AND KEPT LIKELY POPS CONFINED TO THE HIGHER TERRAIN FOR THE TIME BEING. IN WAKE OF THIS SYSTEM...ANOTHER BLAST OF ARCTIC AIR INVADES THE UPPER OHIO VALLEY. 850MB TEMPERATURES BOTTOM OUT BETWEEN -24C TO -26C SUN AFTERNOON WHILE SCATTERED SNOW SHOWERS LINGER WITH THE EXODUS OF THE MID LEVEL TROUGH. SOUTHWEST WINDS ON THE BACK SIDE OF THE SURFACE ANTICYCLONE ERADICATES COLD AIR AND A QUICK WARM UP TO TEMPS ONLY 10 DEGREES BELOW NORMAL IS PROJECTED MONDAY. TEMPERATURES WERE A WEIGHTED BLEND OF EXISTING FORECAST...GFS MEX GUIDANCE...AND ECMWF STATISTICAL GUIDANCE. && .AVIATION /05Z WEDNESDAY THROUGH SUNDAY/... STRATUS WILL CONTINUE OVERNIGHT AT FKL/DUJ/LBE...WITH THE WESTERN EDGE OF STRATUS CURRENTLY HOVERING JUST EAST OF AGC/MGW. LOW CONFIDENCE FORECAST IN WHETHER THOSE TWO TERMINALS WILL BE IMPACTED...BUT HAVE PULLED THE MENTION OF STRATUS PREVIOUSLY IN THE PIT/BVI/HLG TAFS. MVFR FOG HAS ALSO MOVED INTO ZZV...AND SHOULD PERSIST THROUGH THE NIGHT. STRATUS SHOULD DIMINISH IN COVERAGE AFTER SUNRISE...ALTHOUGH FKL/DUJ COULD POTENTIALLY STAY IN THE STRATUS THROUGH THE TAF PERIOD. HAVE GONE MORE PESSIMISTIC THAN PREVIOUS TAFS FOR THOSE TWO SITES. COLD FRONT PUSHES THROUGH THE REGION THIS EVENING...BRINGING RESTRICTIONS AND A SHIFT IN THE WINDS. STILL UNSURE OF HOW LOW VISIBILITIES WILL DROP WITH SNOW SHOWERS...BUT HAVE AT LEAST BROUGHT A MENTION OF SNOW INTO SEVERAL SITES. OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... RESTRICTIONS WILL CONTINUE INTO THURSDAY BEHIND THE COLD FRONT. PERIODIC RESTRICTIONS ARE THEN LIKELY INTO THE WEEKEND WITH A SERIES OF DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/33
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 PM EST WED FEB 11 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 419 PM EST WED FEB 11 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR TROF OVER CENTRAL NAMERICA DOWNSTREAM OF A RDG OVER THE W. SEVERAL SHRTWVS ARE EMBEDDED WITHIN THIS TROF...AND THEIR PRESENCE IS RESPONSIBLE FOR 00Z-12Z H3 HGT FALLS IN EXCESS OF 200M AT YPL. THE FIRST DISTURBANCE THAT BROUGHT THE LIGHT SN LAST NGT IS NOW MOVING E INTO WRN QUEBEC. A SECOND SHRTWV THAT BROUGHT ANOTHER ROUND OF MORE WDSPRD LIGHT SN THIS MRNG IS NOW MOVING TO THE E OF THE AREA...WITH SUBSIDENCE IN ITS WAKE...WHICH LOWERED THE INVRN BASE TO H9 AT INL AT 12Z...NOW RESTRICTING SN SHOWERS MAINLY TO AREAS NEAR LK SUP IMPACTED BY THE COLD NW FLOW IN ITS WAKE. NW SFC WINDS HAVE BEEN GUSTING AS HI AS 35 MPH...RESULTING IN SOME BLSN/REDUCED VSBYS. LOOKING TO THE NW... AN EVEN STRONGER SHRTWV IS DIGGING SEWD THRU MANITOBA AND TOWARD NW MN. 12Z H85-7 TEMPS WERE AS LO AS -30C/-28C AT THE PAS MANITOBA WITHIN THE COLD SURGE ACCOMPANYING THIS SHRTWV. THE 12Z RAOB AT THAT SITE ALSO SHOWED A FAIRLY MOIST LYR UP TO JUST ABOVE H7. MAIN FCST CONCERNS THRU THU ARE NUMEROUS AND RELATED TO GOING HEADLINES/LES COVERAGE/AMOUNTS/WINDS AND BLSN AS WELL AS WIND CHILLS THAT WL ACCOMPANY THIS INCOMING ARCTIC SURGE ASSOCIATED WITH MANITOBA SHRTWV. LATE TODAY/TNGT...SHRTWV NOW DIGGING THRU SRN MANITBOA IS FCST TO DIVE TO NEAR THE MN ARROWHEAD BY 00Z AND INTO THE LOWER LKS BY 12Z THU. THE ARRIVAL OF THE STRONGER DYNAMIC FORCING/DEEPER MSTR/CYC NW VEERING N FLOW THIS EVNG ASSOCIATED WITH THIS DISTURBANCE WL BRING A PERIOD OF LK ENHANCED SN IN AREAS FAVORED BY THESE WINDS AS THE ACCOMPANYING CAA CAUSES H85 TEMPS TO BOTTOM OUT AS LO AS -25C TO -27C BY 12Z THU. MIXING OF THE H925 WINDS AS HI AS 35-40 KTS WITH THE VIGOROUS CAA WL CAUSE VERY GUSTY WINDS AND BLSN AS WELL... ESPECIALLY IN OPEN AREAS NEAR LK SUP. STEADILY SHIFTING WINDS AND THE ARRIVAL OF THE VERY COLD AIR THAT WL NEARLY ELIMINATE THE DGZ AND GUSTY WINDS THAT WL FRAGMENT THE SN FLAKES AND FURTHER LOWER SN/ WATER RATIOS WL LIMIT LES AMOUNTS. THE HIER RES MODELS INDICATE THE HEAVIEST SN WL FALL IN WRN ALGER COUNTY...WITH MORE PERSISTENT LLVL CNVGC THERE ENHANCED BY THE PRESENCE OF A LARGE AMOUNT OF ICE BTWN THE KEWEENAW AND MARQUETTE THAT WL ENHANCE A BIT OF A WNW LAND BREEZE COMPONENT OFF THE W HALF OF UPR MI. THE STRONG LLVL WINDS WL BLOW THESE SN SHOWERS FARTHER INLAND AND INTO DELTA COUNTY. THE ICE COVER OVER FAR ERN LK SUP AND VEERING FLOW TO THE N THAT LIMITS OVERWATER TRAJECTORY INTO LUCE COUNTY WL HAMPER SN ACCUMS OVER THE FAR ERN CWA. THE COMBINATION OF THE STRONG WINDS/LO TEMPS FALLING BLO ZERO WL CAUSE WIND CHILLS TO DIP AS LO AS -25F TO PERHAPS -30F. LATE TNGT...VIGOROUS DNVA/DEEP LYR QVECTOR DVGC/STEADILY RISING H5 HGTS...FCST UP TO 100M BTWN 06Z-12Z OVER THE FAR W AT IWD...IN THE WAKE OF THE DIGGING SHRTWV ARE FCST TO SHARPLY LOWER THE SUBSIDENCE INVRN BASE TOWARD 2K FT AT IWD WL BRING A DIMINISHING TREND TO THE LES. WEAKENING PRES GRADIENT/DIMINISHING LLVL WINDS FOLLOWING SHIFT OF PRES CENTER TO THE E OF UPR MI WL CAUSE THE BLSN TO SUBSIDE A BIT AS WELL. THU...STEADILY RISING HGTS UNDER THE DNVA/LARGE SCALE QVECTOR DVGC IN THE WAKE OF DEPARTING SHRTWV TOWARD THE MID ATLANTIC STATES AND AHEAD OF SHRTWV RDG AXIS MOVING TOWARD THE UPR LKS THAT CAUSE A CONTINUED LOWERING OF THE INVRN BASE TOWARD 2-3K FT EVEN OVER THE E HALF LATE IN THE DAY WL BRING ABOUT A DIMINISHING TREND OF THE LES...LATER OVER THE E. DIMINISHING/BACKING WINDS TOWARD THE NW WITH APRCH OF SFC HI PRES RDG UNVER THE SUBSIDENCE WL CAUSE THE HEAVIER LES OVER WRN ALGER COUNTY TO SHIFT TO THE E. AS FOR THE HEADLINES...ALTHOUGH A GOOD DEAL OF ICE COVER IN THE LK SUP NEARSHORE AREAS WL LIMIT SN TOTALS A BIT COMPARED TO WHAT WOULD HAVE HAPPENED EARLY IN THE SEASON...GUSTY WINDS/BLSN EXACERBATED BY THE NEARSHORE SN COVERED ICE WL BE SUFFICIENT TO WARRANT CONTINUED HEADLINES. WILL CONTINUE THE WARNING FOR ALGER COUNTY GIVEN SUPPORT FM THE HI RES MODELS FOR THE HEAVIEST QPF IN THE WESTERN PART OF THAT COUNTY. ADDED WIND CHILL ADVYS FOR LUCE AND DICKINSON/IRON COUNTIES WITH WIND CHILLS FALLING AS LO AS -28F IN THE PRESENCE OF SUSTAINED N WIND NEAR 10 MPH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 500 PM EST WED FEB 11 2015 THE REGION IS NOW AMIDST AN ACTIVE PATTERN THAT WILL CONTINUE THROUGH THE PERIOD. THIS PATTERN IS SOMEWHAT REMINISCENT TO LAST WINTER AS A BROAD TROUGH BUILDS ACROSS EASTERN NORTH AMERICA. CONCERNS CONTINUE TO GROW FOR POOR CONDITIONS FRIDAY NIGHT AND SATURDAY WITH THE ARRIVAL OF SOME OF THE COLDEST AIR OF THE SEASON. STRONG WINDS WILL LEAD TO VERY LOW VISIBILITIES ALONG LAKE SUPERIOR...WITH BLIZZARD CONDITIONS QUITE POSSIBLE ALONG LAKE SUPERIOR TO START THE WEEKEND. THURSDAY NIGHT...A BROAD TROUGH CENTERED NEAR EASTERN HUDSON BAY WILL SLOWLY SHIFT NORTHEASTWARD AS AN ASSOCIATED SFC TROUGH TRACKS ACROSS THE LOWER GREAT LAKES. A SUBTLE RIDGE WILL SHIFT ACROSS THE CWA THURSDAY NIGHT. HOWEVER...WITH COLD AIR LINGERING AROUND AND INVERSION HEIGHTS REMAINING AROUND 3KFT...SOME LES WILL CONTINUE ACROSS THE EAST BEFORE WINDS BACK TO THE SW BY DAYBREAK FRIDAY. FRIDAY THROUGH SATURDAY...A STRENGTHENING UPPER JET COMBINED WITH A POTENT SHORTWAVE TROUGH DIGGING SE INTO NW ONTARIO WILL INDUCE A SFC LOW NORTH OF LAKE SUPERIOR FRIDAY MORNING. WEAK ISENTROPIC LIFT AHEAD OF THIS LOW WILL SPREAD LIGHT SNOW ACROSS MUCH OF THE CWA DURING THE DAY FRIDAY...WITH ACCUMULATIONS GENERALLY AROUND AN INCH. BY EARLY-AFTERNOON...THE COLD FRONT ASSOCIATED WITH THE SFC LOW WILL BE NEARING THE WESTERN CWA. H8 TEMPS FALLING FROM -15 TO -30C OVER 12-18 HOURS WILL ALLOW FOR A RAPID ONSET OF LAKE EFFECT SNOW FOR THE NW-WIND SNOW BELTS ACROSS THE WEST BY LATE FRIDAY AFTERNOON. THE WIND WILL QUICKLY BECOME NORTHERLY FOR ALL OF UPPER MI SATURDAY EVENING AS THE SFC LOW TRACKS INTO NW LAKE HURON/GEORGIAN BAY. TEMPERATURES WILL FALL QUICKLY...WITH HIGHS FAILING TO RISE ABOVE ZERO FOR MOST OF THE AREA ON SATURDAY. WITH BLUSTERLY CONDITIONS...WIND CHILLS WILL BE -20 TO -30F LATE FRIDAY NIGHT THROUGH SATURDAY NIGHT. THERE IS LITTLE DOUBT THAT WINDS WILL BE QUITE STRONG /GUSTING OVER 40MPH ALONG LAKE SUPERIOR/ BEHIND THIS FRONT AS AN ARCTIC HIGH OF APPROX 1050MB BUILDS SE OUT OF SASKATCHEWAN AND THE 1005MB LOW MOVES TOWARD THE LOWER GREAT LAKES. HOWEVER...THE STRENGTH OF THE PRESSURE GRADIENT WILL DEPEND HEAVILY ON HOW THE UPPER JET AND MID-LEVEL TROUGH INTERACT AS THE LOW MOVES AWAY FROM THE AREA. THE BEST FORCING ON THE LEFT-EXIT OF THE JET LOOKS TO BE SOMEWHAT REMOVED TO THE SOUTH OF THE MAIN SHORTWAVE ENERGY. IF THESE FEATURES CAN COME INTO BETTER ALIGNMENT TO PRODUCE A STRONGER LOW...BLIZZARD CONDITIONS WOULD BE LIKELY ALONG MUCH OF LAKE SUPERIOR FRIDAY NIGHT THROUGH SATURDAY. THE AFOREMENTIONED ISSUES ALSO PRODUCE A STRONG ISALLOBARIC WIND COMPONENT THAT IS MORE PERPENDICULAR THAN PARALLEL TO THE GRADIENT WIND...THUS PROVIDING ONLY MARGINAL ENHANCEMENT TO THE OVERALL WINDS. WITH THE VERY COLD...AND RATHER DRY...ARCTIC AIR...SNOWFLAKE PRODUCTION WILL BE DIFFICULT. THE EXPECTATIONS IS FOR VERY SMALL LOW- RATIO SNOWFLAKES BY LATE FRIDAY NIGHT. FOR THIS REASON...SNOW AMOUNTS ARE NOT OF UTMOST CONCERN WITH THIS SYSTEM. THE COMBINATION OF THE STRONG WINDS AND SMALL SNOWFLAKE SIZE WILL GREATLY REDUCE VISIBILITY. WHITE-OUT CONDITIONS ARE EXPECTED AT TIMES ALONG LAKE SUPERIOR...ESPECIALLY SATURDAY MORNING. THE ONE MAJOR WILD CARD WILL BE THE EVOLUTION OF THE ICE PACK ON LAKE SUPERIOR. ICE MODEL FORECASTS INDICATE THAT TONIGHTS WINDS WILL GREATLY COMPACT THE ICE ALONG THE SOUTHERN SHORE OF LAKE SUPERIOR. THIS WOULD PROVIDE MORE OPEN WATER FOR LES PRODUCTION FOR THE WEEKEND. ADDITIONALLY...THE ICE SHELF OFF SHORE WILL BE YET ANOTHER SOURCE OF SNOW FOR THE WINDS TO BLOW AROUND NEAR THE SHORELINES. WHILE BLIZZARD CONDITIONS ARE APPEARING MORE LIKELY FOR MUCH OF THE KEWEENAW AND AREAS FROM BIG BAY TO GRAND MARAIS ALONG LAKE SUPERIOR FRIDAY NIGHT THROUGH SATURDAY...HAVE DECIDED TO HOLD OFF ON ANY HEADLINES AT THIS TIME FOR TWO REASONS. FIRST...THE MESSAGE PERTAINING TO ONGOING ADVISORIES AND HEADLINES HIGHLIGHTING TONIGHTS WEATHER MAY GET MIXED WITH ANY WATCHES FOR FRI NIGHT AND SAT. SECOND...FORECASTER CONCENSUS IS TO SEE WHAT HAPPENS TONIGHT IN ORDER TO GET A SAMPLE OF WHAT FRIDAY NIGHT AND SAT MAY HOLD. IF CONDITIONS TONIGHT BECOME QUITE POOR...CONFIDENCE WILL SIGNIFICANTLY INCREASE FOR BLIZZARD CONDITIONS EARLY THIS WEEKEND. ANY HEADLINES MAY NOT BE ISSUED UNTIL THURSDAY...AND COULD SKIP ANY WATCHES AND GO STRAIGHT TO A WARNING IF NEED BE. SATURDAY NIGHT AND SUNDAY...LAKE EFFECT SNOW SHOWERS WILL CONTINUE FOR THE NORTH WIND SNOW BELTS AS A WEAK SECONDARY TROUGH TRACKS ACROSS THE AREA IN THE EVENING. A MID-LEVEL/SFC RIDGE BUILDING IN FROM THE NORTHERN PLAINS LATE SATURDAY NIGHT WILL INCREASE CONVERGENCE ACROSS THE EASTERN LAKE. THIS MAY LEAD TO A CONTINUED DOMINATE LES BAND BETWEEN MARQUETTE AND MUNISING AS INVERSION HEIGHTS REMAIN AROUND 5KFT. THIS LES WILL QUICKLY SHIFT OFF SHORE DURING THE DAY SUNDAY AS THE RIDGE WORKS ACROSS LAKE SUPERIOR. MONDAY THROUGH WEDNESDAY...A BROAD TROUGH MOVING IN FROM SOUTH- CENTRAL CANADA WILL BRING SMALL CHANCES OF SNOW FOR MONDAY. THIS TROUGH WILL AMPLIFY MONDAY NIGHT AND CROSS UPPER MI TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING ANOTHER ROUND OF BREEZY CONDITIONS AND INCREASED LES FOR THE NW-WIND SNOW BELTS. HOWEVER...CONDITIONS ARE NET EXPECTED TO BE AS BAD AS EARLY THIS WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1224 PM EST WED FEB 11 2015 SUBSIDENCE IN THE WAKE OF A PASSING DISTURBANCE WILL RESULT IN PREDOMINANT MVFR CONDITIONS AT CMX AND IWD THIS AFTN...BUT GUSTY NW WINDS/BLSN AND A FEW HEAVIER SHSN RELATED TO SURGE OF COLD AIR WL CAUSE AT LEAST TEMPO IFR CONDITIONS AT THESE LOCATIONS. SINCE THE NW WINDS DOWNSLOPE INTO SAW...THAT AIRPORT SHOULD SEE VFR TO AT TIMES MVFR CONDITIONS. AS ANOTHER STRONGER DISTURBANCE/DYNAMIC FORCING AND DEEPER MSTR ARRIVE TNGT ALONG WITH EVEN STRONGER NNW WINDS THAT WL CAUSE CONSIDERABLE BLSN...IFR TO LIFR CONDITIONS WL PREVAIL AT ALL 3 TAF SITES. WITH STRONG SUBSIDENCE/DIMINISHING WINDS AND BLSN FOLLOWING THE PASSAGE OF THIS DISTURBANCE...CONDITIONS WL SLOWLY IMPROVE TO MVFR LATE TNGT/THU MRNG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 419 PM EST WED FEB 11 2015 ONGOING GALES/HEAVY FREEZING SPRAY WILL DIMINISH W-E LATE TONIGHT AND THU WITH THE APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT AND DIMINISHING WINDS/WAVES. ANOTHER ROUND OF GALES/HEAVY FREEZING SPRAY ASSOCIATED WITH ANOTHER ARCTIC AIR INVASION WILL DEVELOP FRI NIGHT AND PERSIST THRU SAT. NOT OUT OF THE QUESTION THERE COULD BE SOME STORM FORCE GUSTS ON SAT...ESPECIALLY OVER THE E HALF. LOW PRESSURE NEAR GEORGIAN BAY WILL SLIDE ACROSS NEW ENGLAND THROUGH THURSDAY AND DEEPEN. HIGH PRESSURE OVER SASKATCHEWAN WILL THEN SETTLE OVER THE MID MISSISSIPPI RIVER VALLEY BY THURSDAY AFTERNOON WITH A RIDGE EXTENDING NORTHWARD ACROSS THE UPPER GREAT LAKES. EXPECT THE RIDGE TO REACH THE LOWER GREAT LAKES ON FRIDAY AS LOW PRESSURE MOVES FROM NORTHERN ONTARIO TO LAKE SUPERIOR. THE LOW WILL DEEPEN AS IT REACHES THE LOWER GREAT LAKES ON SATURDAY AND JUST OFF THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE BUILDING FROM CENTRAL CANADA INTO THE NORTHERN PLAINS ON SATURDAY WILL CROSS THE GREAT LAKES THROUGH MONDAY AS A LOW PRESSURE TROUGH REACHES THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ THURSDAY FOR MIZ001>004-009-084. WINTER WEATHER ADVISORY UNTIL 1 PM EST THURSDAY FOR MIZ013-085. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY FOR MIZ010-011. WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR MIZ005. WINTER STORM WARNING UNTIL 7 PM EST THURSDAY FOR MIZ006. WIND CHILL ADVISORY FROM 4 AM TO 1 PM EST THURSDAY FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ267. GALE WARNING UNTIL 1 PM EST THURSDAY FOR LSZ265-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THURSDAY FOR LSZ266. GALE WARNING UNTIL 4 PM EST THURSDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ264. GALE WARNING UNTIL 10 AM EST THURSDAY FOR LSZ264. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST THURSDAY FOR LSZ263. GALE WARNING UNTIL 7 AM EST THURSDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TK AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EST WED FEB 11 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 419 PM EST WED FEB 11 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR TROF OVER CENTRAL NAMERICA DOWNSTREAM OF A RDG OVER THE W. SEVERAL SHRTWVS ARE EMBEDDED WITHIN THIS TROF...AND THEIR PRESENCE IS RESPONSIBLE FOR 00Z-12Z H3 HGT FALLS IN EXCESS OF 200M AT YPL. THE FIRST DISTURBANCE THAT BROUGHT THE LIGHT SN LAST NGT IS NOW MOVING E INTO WRN QUEBEC. A SECOND SHRTWV THAT BROUGHT ANOTHER ROUND OF MORE WDSPRD LIGHT SN THIS MRNG IS NOW MOVING TO THE E OF THE AREA...WITH SUBSIDENCE IN ITS WAKE...WHICH LOWERED THE INVRN BASE TO H9 AT INL AT 12Z...NOW RESTRICTING SN SHOWERS MAINLY TO AREAS NEAR LK SUP IMPACTED BY THE COLD NW FLOW IN ITS WAKE. NW SFC WINDS HAVE BEEN GUSTING AS HI AS 35 MPH...RESULTING IN SOME BLSN/REDUCED VSBYS. LOOKING TO THE NW... AN EVEN STRONGER SHRTWV IS DIGGING SEWD THRU MANITOBA AND TOWARD NW MN. 12Z H85-7 TEMPS WERE AS LO AS -30C/-28C AT THE PAS MANITOBA WITHIN THE COLD SURGE ACCOMPANYING THIS SHRTWV. THE 12Z RAOB AT THAT SITE ALSO SHOWED A FAIRLY MOIST LYR UP TO JUST ABOVE H7. MAIN FCST CONCERNS THRU THU ARE NUMEROUS AND RELATED TO GOING HEADLINES/LES COVERAGE/AMOUNTS/WINDS AND BLSN AS WELL AS WIND CHILLS THAT WL ACCOMPANY THIS INCOMING ARCTIC SURGE ASSOCIATED WITH MANITOBA SHRTWV. LATE TODAY/TNGT...SHRTWV NOW DIGGING THRU SRN MANITBOA IS FCST TO DIVE TO NEAR THE MN ARROWHEAD BY 00Z AND INTO THE LOWER LKS BY 12Z THU. THE ARRIVAL OF THE STRONGER DYNAMIC FORCING/DEEPER MSTR/CYC NW VEERING N FLOW THIS EVNG ASSOCIATED WITH THIS DISTURBANCE WL BRING A PERIOD OF LK ENHANCED SN IN AREAS FAVORED BY THESE WINDS AS THE ACCOMPANYING CAA CAUSES H85 TEMPS TO BOTTOM OUT AS LO AS -25C TO -27C BY 12Z THU. MIXING OF THE H925 WINDS AS HI AS 35-40 KTS WITH THE VIGOROUS CAA WL CAUSE VERY GUSTY WINDS AND BLSN AS WELL... ESPECIALLY IN OPEN AREAS NEAR LK SUP. STEADILY SHIFTING WINDS AND THE ARRIVAL OF THE VERY COLD AIR THAT WL NEARLY ELIMINATE THE DGZ AND GUSTY WINDS THAT WL FRAGMENT THE SN FLAKES AND FURTHER LOWER SN/ WATER RATIOS WL LIMIT LES AMOUNTS. THE HIER RES MODELS INDICATE THE HEAVIEST SN WL FALL IN WRN ALGER COUNTY...WITH MORE PERSISTENT LLVL CNVGC THERE ENHANCED BY THE PRESENCE OF A LARGE AMOUNT OF ICE BTWN THE KEWEENAW AND MARQUETTE THAT WL ENHANCE A BIT OF A WNW LAND BREEZE COMPONENT OFF THE W HALF OF UPR MI. THE STRONG LLVL WINDS WL BLOW THESE SN SHOWERS FARTHER INLAND AND INTO DELTA COUNTY. THE ICE COVER OVER FAR ERN LK SUP AND VEERING FLOW TO THE N THAT LIMITS OVERWATER TRAJECTORY INTO LUCE COUNTY WL HAMPER SN ACCUMS OVER THE FAR ERN CWA. THE COMBINATION OF THE STRONG WINDS/LO TEMPS FALLING BLO ZERO WL CAUSE WIND CHILLS TO DIP AS LO AS -25F TO PERHAPS -30F. LATE TNGT...VIGOROUS DNVA/DEEP LYR QVECTOR DVGC/STEADILY RISING H5 HGTS...FCST UP TO 100M BTWN 06Z-12Z OVER THE FAR W AT IWD...IN THE WAKE OF THE DIGGING SHRTWV ARE FCST TO SHARPLY LOWER THE SUBSIDENCE INVRN BASE TOWARD 2K FT AT IWD WL BRING A DIMINISHING TREND TO THE LES. WEAKENING PRES GRADIENT/DIMINISHING LLVL WINDS FOLLOWING SHIFT OF PRES CENTER TO THE E OF UPR MI WL CAUSE THE BLSN TO SUBSIDE A BIT AS WELL. THU...STEADILY RISING HGTS UNDER THE DNVA/LARGE SCALE QVECTOR DVGC IN THE WAKE OF DEPARTING SHRTWV TOWARD THE MID ATLANTIC STATES AND AHEAD OF SHRTWV RDG AXIS MOVING TOWARD THE UPR LKS THAT CAUSE A CONTINUED LOWERING OF THE INVRN BASE TOWARD 2-3K FT EVEN OVER THE E HALF LATE IN THE DAY WL BRING ABOUT A DIMINISHING TREND OF THE LES...LATER OVER THE E. DIMINISHING/BACKING WINDS TOWARD THE NW WITH APRCH OF SFC HI PRES RDG UNVER THE SUBSIDENCE WL CAUSE THE HEAVIER LES OVER WRN ALGER COUNTY TO SHIFT TO THE E. AS FOR THE HEADLINES...ALTHOUGH A GOOD DEAL OF ICE COVER IN THE LK SUP NEARSHORE AREAS WL LIMIT SN TOTALS A BIT COMPARED TO WHAT WOULD HAVE HAPPENED EARLY IN THE SEASON...GUSTY WINDS/BLSN EXACERBATED BY THE NEARSHORE SN COVERED ICE WL BE SUFFICIENT TO WARRANT CONTINUED HEADLINES. WILL CONTINUE THE WARNING FOR ALGER COUNTY GIVEN SUPPORT FM THE HI RES MODELS FOR THE HEAVIEST QPF IN THE WESTERN PART OF THAT COUNTY. ADDED WIND CHILL ADVYS FOR LUCE AND DICKINSON/IRON COUNTIES WITH WIND CHILLS FALLING AS LO AS -28F IN THE PRESENCE OF SUSTAINED N WIND NEAR 10 MPH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 419 AM EST WED FEB 11 2015 NAM SHOWS A DEEP 500 MB TROUGH OVER THE GREAT LAKES REGION 12Z THU WITH A 500 MB RIDGE ON THE WEST COAST. PATTERN CHANGES LITTLE FOR 12Z FRI. A CLOSED 500 MB LOW HEADS SOUTH OUT OF HUDSON BAY FRI NIGHT AND DIGS A DEEP TROUGH INTO THE UPPER GREAT LAKES 12Z SAT. AN ALBERTA CLIPPER SYSTEM MOVES THROUGH THE AREA LATER FRI AFTERNOON AND EVENING AND THE NAM HAS SOME 850-500 MB Q-VECTOR CONVERGENCE AND DEEPER MOISTURE MOVE THROUGH THE CWA FRI BEFORE MOVING OUT FRI NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST AS PREVIOUS FORECAST SEEMED TO HAVE THINGS WELL IN HAND. LAKE EFFECT SNOW CONTINUES INTO THU WITH WINDS DECREASING DURING THE MORNING. WILL CONTINUE WITH THE ADVISORIES INTO THU FOR THE SNOW AND BLOWING SNOW. CLIPPER SYSTEM FOR FRI HAS WINDS INCREASING FRI NIGHT AND SNOW AMOUNTS DO NOT LOOK REAL IMPRESSIVE...BUT WILL GET SOME BLOWING AND DRIFTING OF SNOW AGAIN FRI NIGHT INTO SAT. IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE UPPER GREAT LAKES 12Z SAT WITH COLD AIR MOVING ACROSS THE AREA. 850 MB TEMPERATURES ACROSS LAKE SUPERIOR ARE FROM -25C TO -30C AT THAT TIME. THIS 500 MB TROUGH MOVES TO THE EASTERN U.S. 12Z SUN WITH SFC HIGH PRESSURE OVER THE AREA. A COLD FRONT THEN MOVES INTO THE UPPER GREAT LAKES 12Z MON WITH 850 MB TEMPERATURES AROUND -18C. COOLER AIR IS AGAIN POISED TO MOVE INTO THE AREA ON TUE. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THIS FORECAST PERIOD WITH SOME LAKE EFFECT SNOW BEING THE PREVALENT PCPN TYPE. AN ALBERTA CLIPPER SYSTEM HAS ALREADY MOVED THROUGH THE AREA ON SAT. WILL HAVE TO CONTEND WITH WIND CHILL WARNINGS AND ADVISORIES FOR SATURDAY AND WILL MENTION IN THE HWO FOR NOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1224 PM EST WED FEB 11 2015 SUBSIDENCE IN THE WAKE OF A PASSING DISTURBANCE WILL RESULT IN PREDOMINANT MVFR CONDITIONS AT CMX AND IWD THIS AFTN...BUT GUSTY NW WINDS/BLSN AND A FEW HEAVIER SHSN RELATED TO SURGE OF COLD AIR WL CAUSE AT LEAST TEMPO IFR CONDITIONS AT THESE LOCATIONS. SINCE THE NW WINDS DOWNSLOPE INTO SAW...THAT AIRPORT SHOULD SEE VFR TO AT TIMES MVFR CONDITIONS. AS ANOTHER STRONGER DISTURBANCE/DYNAMIC FORCING AND DEEPER MSTR ARRIVE TNGT ALONG WITH EVEN STRONGER NNW WINDS THAT WL CAUSE CONSIDERABLE BLSN...IFR TO LIFR CONDITIONS WL PREVAIL AT ALL 3 TAF SITES. WITH STRONG SUBSIDENCE/DIMINISHING WINDS AND BLSN FOLLOWING THE PASSAGE OF THIS DISTURBANCE...CONDITIONS WL SLOWLY IMPROVE TO MVFR LATE TNGT/THU MRNG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 419 PM EST WED FEB 11 2015 ONGOING GALES/HEAVY FREEZING SPRAY WILL DIMINISH W-E LATE TONIGHT AND THU WITH THE APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT AND DIMINISHING WINDS/WAVES. ANOTHER ROUND OF GALES/HEAVY FREEZING SPRAY ASSOCIATED WITH ANOTHER ARCTIC AIR INVASION WILL DEVELOP FRI NIGHT AND PERSIST THRU SAT. NOT OUT OF THE QUESTION THERE COULD BE SOME STORM FORCE GUSTS ON SAT...ESPECIALLY OVER THE E HALF. LOW PRESSURE NEAR GEORGIAN BAY WILL SLIDE ACROSS NEW ENGLAND THROUGH THURSDAY AND DEEPEN. HIGH PRESSURE OVER SASKATCHEWAN WILL THEN SETTLE OVER THE MID MISSISSIPPI RIVER VALLEY BY THURSDAY AFTERNOON WITH A RIDGE EXTENDING NORTHWARD ACROSS THE UPPER GREAT LAKES. EXPECT THE RIDGE TO REACH THE LOWER GREAT LAKES ON FRIDAY AS LOW PRESSURE MOVES FROM NORTHERN ONTARIO TO LAKE SUPERIOR. THE LOW WILL DEEPEN AS IT REACHES THE LOWER GREAT LAKES ON SATURDAY AND JUST OFF THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE BUILDING FROM CENTRAL CANADA INTO THE NORTHERN PLAINS ON SATURDAY WILL CROSS THE GREAT LAKES THROUGH MONDAY AS A LOW PRESSURE TROUGH REACHES THE NORTHERN PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ THURSDAY FOR MIZ001>004-009-084. WINTER WEATHER ADVISORY UNTIL 1 PM EST THURSDAY FOR MIZ013-085. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST THURSDAY FOR MIZ010-011. WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR MIZ005. WINTER STORM WARNING UNTIL 7 PM EST THURSDAY FOR MIZ006. WIND CHILL ADVISORY FROM 4 AM TO 1 PM EST THURSDAY FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ267. GALE WARNING UNTIL 1 PM EST THURSDAY FOR LSZ265-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THURSDAY FOR LSZ266. GALE WARNING UNTIL 4 PM EST THURSDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ264. GALE WARNING UNTIL 10 AM EST THURSDAY FOR LSZ264. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST THURSDAY FOR LSZ263. GALE WARNING UNTIL 7 AM EST THURSDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...07 AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
419 AM EST WED FEB 11 2015 .UPDATE... ISSUED AT 945 PM EST TUE FEB 10 2015 FCST NOT QUITE GOING AS PLANNED AS IT LOOKS LIKE SNOWFALL AMOUNTS ARE GOING TO FALL SHORT OF ADVY CRITERIA BASED ON RADAR IMAGERY/OBS AND TRENDS. HAVE CUT SNOW AMOUNTS DOWN TO MOSTLY 1-2 INCHES FOR THE TONIGHT PERIOD...NOT ADVY WORTHY AMOUNTS. A FEW SPOTS MAY REACH 3. THOSE HIGHER AMOUNTS MAY BE FOUND OVER THE KEWEENAW AND PERHAPS SOME PORTIONS OF SCNTRL UPPER MI...CLOSER TO VORT MAX AND MORE CONSOLIDATED SNOW AREA MOVING ACROSS WI. BIGGER CHANGE WAS TO ADD -FZDZ INTO THE FCST BASED LARGELY ON UPSTREAM OBS...BUT ALSO BASED ON SOME HINTS IN FCST SOUNDINGS THAT THERE WILL BE A LOSS OF ICE CRYSTALS. WILL LET ADVY PLAY OUT WITH THE INTRODUCTION OF -FZDZ. THAT SAID...SINCE IT WILL HAVE SNOWED BEFORE -FZDZ OCCURS...IMPACT OF THE -FZDZ ON ROADWAYS WILL LIKELY BE MUCH MORE LIMITED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 353 PM EST TUE FEB 10 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A POLAR BRANCH WNW FLOW ALOFT OVER THE UPPER GREAT LKS BTWN AN ARCTIC BRANCH FARTHER N IN CANADA AND A SUBTROPICAL BRANCH OVER THE SRN CONUS. SHRTWV EMBEDDED IN THIS POLAR BRANCH FLOW IS MOVING ESE TOWARD WRN MN... CAUSING 12HR H3 HGT FALLS UP TO 120M. ACCOMPANYING AREA OF PCPN IS OVER MN UNDER AREA OF DEEPER MSTR ENHANCED BY UPR DVGC AHEAD OF THIS FEATURE AS WELL AS WAA/ISENTROPIC ASCENT BEST SHOWN ON THE 290-300K SFCS /ABOUT H6-75/ AND SPREADING TO THE NE TOWARD THE WRN CWA. AHEAD OF THIS PCPN...SKIES OVER UPR MI ARE MAINLY CLDY WITH MOIST LLVL AIRMASS TRAPPED UNDER SHARP INVRN BASE ARND H9. THERE HAS BEEN SOME PATCHY LIGHT FREEZING DZ IN AREAS OVER THE KEWEENAW/NCENTRAL WHERE LLVL ESE FLOW UPSLOPES. MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON SN AMOUNTS ASSOCIATED WITH INCOMING SHRTWV AND GOING HEADLINES. LATE TODAY/TNGT...AS AREA OF ISENTROPIC ASCENT/UPR DVGC/DEEP LYR QVECTOR CNVGC IN ADVANCE OF SHRTWV MOVING THRU MN PUSHES INTO THE CWA...EXPECT SN TO OVERSPREAD THE AREA W-E. MODELS ARE INDICATING A 9-12 HR PERIOD OF FORCING BEFORE THE ARRIVAL OF SOME DEEP LYR QVECTOR DVGC/DNVA OVER THE W LATE IN THE WAKE OF THE SHRTWV/SFC LO MOVING OVER CENTRAL UPR MI/NRN LK SUP BY 12Z WED. BUT SOME LINGERING DRY AIR JUST ABOVE THE INVRN BASE WL HINDER THE DEVELOPMENT OF STEADIER PCPN...ESPECIALLY IN AREAS THAT EXPERIENCE A DOWNSLOPE WIND COMPONENT WITH ONGOING S FLOW...SO THE ACTUAL WINDOW FOR STEADIER SN WL ACTUALLY BE 6-9 HRS. MODELS INDICATE ABOUT 2.5 G/KG SPECIFIC HUMIDITY WL BE PRESENT ON THE 290K SFC ARND H7...WHICH WOULD SUPPORT GOING FCST UP 3 TO 4 INCHES OF SNOW DURING THE 6-9 HR WINDOW OF STEADY PCPN. ABSENCE OF ANY PHASING WITH THE ARCTIC/ SUBTROPICAL BRANCES AND SHARPER UPR DVGC ASSOCIATED WITH THE JET CORES IN THOSE BRANCHES AS WELL AS FCST HI THIN DGZ THAT WL LIMIT SN/WATER RATIOS WL LIMIT SN TOTALS. LATE TNGT...EXPECT THE PCPN OVER THE W TO DIMINISH FOR AT LEAST A TIME FOLLOWING THE EXIT OF THE DEEP UPR FORCING AND PASSAGE OF LO PRES TROF ACCOMPANYING SFC LO MOVING THRU NRN LK SUP. THE INCOMING AIRMASS WL BE INITIALLY TOO WARM TO SUPPORT LES. GOING HEADLINES APPEAR TO BE IN GOOD SHAPE. DID ADD LUCE COUNTY TO THE HEADLINE MIX WITH ARND 3 INCHES EXPECTED THERE BEFORE THE SN DIMINISHES LATER ON WED MRNG. WED...LINGERING STEADY SN OVER THE ERN CWA SHOULD END IN THE MRNG WITH THE PASSAGE OF SHRTWV/ACCOMPANYING SFC LO PRES TROF AND EXIT OF DEEP LYR QVECTOR CNVGC. GUIDANCE THEN SHOWS AN ARCTIC BRANCH SHRTWV DIGGING SHARPLY TO NEAR WRN LK SUP BY 00Z THU...WITH H85 TEMPS FALLING TOWARD -21C OVER THE NW CWA BY 00Z THU FOLLOWING ATTENDANT COLD FROPA. NNW H925 WINDS INCRSG UP TO 30-35KTS IN THE SHARP CYC FLOW LEFT IN THE WAKE OF THIS DISTURBANCE AND DEEPENING LO PRES EXITING TO THE E IN THE STRONG CAA WL RESULT IN VERY GUSTY SFC WINDS THAT WL AT LEAST APRCH ADVY LEVELS AS WELL AS CONSIDERABLE BLSN IN ADDITION TO THE LES IN EXPOSED AREAS NEAR LK SUP. THE COMBINATION OF THE SHARP CYC FLOW AS WELL AS SOME DPVA/DEEP LYR QVECTOR CNVGC/ DEEPENING MSTR WITH THE STRONG CAD MAY BRING A PERIOD OF SOME LK ENHANCED SN LATE IN THE DAY OVER THE W. LATER SHIFTS WL NEED TO INCLUDE ADDITIONAL HEADLINES FOR AT LEAST AREAS NEAR LK SUP FOR LATER WED. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 419 AM EST WED FEB 11 2015 NAM SHOWS A DEEP 500 MB TROUGH OVER THE GREAT LAKES REGION 12Z THU WITH A 500 MB RIDGE ON THE WEST COAST. PATTERN CHANGES LITTLE FOR 12Z FRI. A CLOSED 500 MB LOW HEADS SOUTH OUT OF HUDSON BAY FRI NIGHT AND DIGS A DEEP TROUGH INTO THE UPPER GREAT LAKES 12Z SAT. AN ALBERTA CLIPPER SYSTEM MOVES THROUGH THE AREA LATER FRI AFTERNOON AND EVENING AND THE NAM HAS SOME 850-500 MB Q-VECTOR CONVERGENCE AND DEEPER MOISTURE MOVE THROUGH THE CWA FRI BEFORE MOVING OUT FRI NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST AS PREVIOUS FORECAST SEEMED TO HAVE THINGS WELL IN HAND. LAKE EFFECT SNOW CONTINUES INTO THU WITH WINDS DECREASING DURING THE MORNING. WILL CONTINUE WITH THE ADVISORIES INTO THU FOR THE SNOW AND BLOWING SNOW. CLIPPER SYSTEM FOR FRI HAS WINDS INCREASING FRI NIGHT AND SNOW AMOUNTS DO NOT LOOK REAL IMPRESSIVE...BUT WILL GET SOME BLOWING AND DRIFTING OF SNOW AGAIN FRI NIGHT INTO SAT. IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE UPPER GREAT LAKES 12Z SAT WITH COLD AIR MOVING ACROSS THE AREA. 850 MB TEMPERATURES ACROSS LAKE SUPERIOR ARE FROM -25C TO -30C AT THAT TIME. THIS 500 MB TROUGH MOVES TO THE EASTERN U.S. 12Z SUN WITH SFC HIGH PRESSURE OVER THE AREA. A COLD FRONT THEN MOVES INTO THE UPPER GREAT LAKES 12Z MON WITH 850 MB TEMPERATURES AROUND -18C. COOLER AIR IS AGAIN POISED TO MOVE INTO THE AREA ON TUE. TEMPERATURES WILL REMAIN WELL BELOW NORMAL THIS FORECAST PERIOD WITH SOME LAKE EFFECT SNOW BEING THE PREVALENT PCPN TYPE. AN ALBERTA CLIPPER SYSTEM HAS ALREADY MOVED THROUGH THE AREA ON SAT. WILL HAVE TO CONTEND WITH WIND CHILL WARNINGS AND ADVISORIES FOR SATURDAY AND WILL MENTION IN THE HWO FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1157 PM EST TUE FEB 10 2015 AT KIWD/KCMX...EXPECT MVFR CONDITIONS TO GENERALLY BE THE RULE OVERNIGHT WITH OCNL -SN THAT MAY MIX AT TIMES WITH -FZDZ. WINDS WILL SHIFT TO AN UPSLOPE W FOLLOWING THE PASSAGE OF A LOW PRES TROF LATE IN THE NIGHT/EARLY MORNING...AND THIS SHOULD BRING A PERIOD OF IFR CONDITIONS. COLD FROPA AROUND MID MORNING WILL THEN BRING STRONGER NW WINDS/LAKE EFFECT SNOW...MAINTAINING IFR CONDITIONS. PASSAGE OF ANOTHER SFC TROF LATE IN THE AFTN/EARLY EVENING WILL INCREASE LES AND PROBABLY DROP CONDITIONS TO LIFR IN -SHSN/BLSN. AT KSAW...EXPECT MVFR CONDITIONS TO FALL TO IFR IN THE NEXT FEW HRS AS UPSLOPE S WIND CONTINUES. OCNL -SN MAY MIX AT TIMES WITH -FZDZ. CONDITIONS SHOULD RETURN TO MVFR WITH STRENGTHENING DOWNSLOPE W WIND VEERING NW FOLLOWING LOW PRES TROF PASSAGE EARLY THIS MORNING AND THEN COLD FROPA LATER IN THE MORNING. PASSAGE OF ANOTHER SFC TROF THIS EVENING WILL SIGNIFICANTLY INCREASE LAKE EFFECT SNOW/WINDS AND BLSN...RESULTING IN CONDITIONS FALLING TO LIFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 419 AM EST WED FEB 11 2015 TWO GALE AND HEAVY FREEZING SPRAY EVENTS WILL OCCUR DURING THE FORECAST PERIOD. THE FIRST WILL BE THROUGH THU AND THE SECOND WILL BE FRIDAY NIGHT AND SATURDAY. THE STRONGER EVENT WILL BE FRIDAY NIGHT AND SATURDAY WITH GALES TO 45 KNOTS AND THERE COULD BE SOME STORM FORCE GUSTS WITH THOSE. LOW PRESSURE OVER LAKE SUPERIOR THIS MORNING WILL MOVE TO JUST EAST OF GEORGIAN BAY BY THIS EVENING. STRONG HIGH PRESSURE WILL MOVE INTO SOUTH CENTRAL CANADA BY THIS EVENING AND WILL MOVE TO THE MID MISSISSIPPI VALLEY ON THURSDAY AND BUILD A RIDGE ACROSS LAKE SUPERIOR LATE THURSDAY INTO THURSDAY NIGHT. A LOW PRESSURE SYSTEM ACROSS MANITOBA THURSDAY NIGHT WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR FRIDAY AFTERNOON AND EVENING. ANOTHER STRONG HIGH PRESSURE ACROSS CENTRAL CANADA SATURDAY MORNING WILL MOVE TO THE UPPER GREAT LAKES ON SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST THURSDAY FOR MIZ001>004-084. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR MIZ013-085. WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR MIZ006-014-085. WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST THURSDAY FOR MIZ009. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST THURSDAY FOR MIZ005. WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 PM EST THURSDAY FOR MIZ006. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR LSZ267. GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST THURSDAY FOR LSZ267. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EST THURSDAY FOR LSZ266. GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 PM EST THURSDAY FOR LSZ266. GALE WARNING FROM 1 PM THIS AFTERNOON TO 1 PM EST THURSDAY FOR LSZ265. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 1 PM EST THURSDAY FOR LSZ264. GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST THURSDAY FOR LSZ264. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST THURSDAY FOR LSZ263. GALE WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST THURSDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...KC LONG TERM...07 AVIATION...ROLFSON MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST TUE FEB 10 2015 .UPDATE... ISSUED AT 945 PM EST TUE FEB 10 2015 FCST NOT QUITE GOING AS PLANNED AS IT LOOKS LIKE SNOWFALL AMOUNTS ARE GOING TO FALL SHORT OF ADVY CRITERIA BASED ON RADAR IMAGERY/OBS AND TRENDS. HAVE CUT SNOW AMOUNTS DOWN TO MOSTLY 1-2 INCHES FOR THE TONIGHT PERIOD...NOT ADVY WORTHY AMOUNTS. A FEW SPOTS MAY REACH 3. THOSE HIGHER AMOUNTS MAY BE FOUND OVER THE KEWEENAW AND PERHAPS SOME PORTIONS OF SCNTRL UPPER MI...CLOSER TO VORT MAX AND MORE CONSOLIDATED SNOW AREA MOVING ACROSS WI. BIGGER CHANGE WAS TO ADD -FZDZ INTO THE FCST BASED LARGELY ON UPSTREAM OBS...BUT ALSO BASED ON SOME HINTS IN FCST SOUNDINGS THAT THERE WILL BE A LOSS OF ICE CRYSTALS. WILL LET ADVY PLAY OUT WITH THE INTRODUCTION OF -FZDZ. THAT SAID...SINCE IT WILL HAVE SNOWED BEFORE -FZDZ OCCURS...IMPACT OF THE -FZDZ ON ROADWAYS WILL LIKELY BE MUCH MORE LIMITED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 353 PM EST TUE FEB 10 2015 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A POLAR BRANCH WNW FLOW ALOFT OVER THE UPPER GREAT LKS BTWN AN ARCTIC BRANCH FARTHER N IN CANADA AND A SUBTROPICAL BRANCH OVER THE SRN CONUS. SHRTWV EMBEDDED IN THIS POLAR BRANCH FLOW IS MOVING ESE TOWARD WRN MN... CAUSING 12HR H3 HGT FALLS UP TO 120M. ACCOMPANYING AREA OF PCPN IS OVER MN UNDER AREA OF DEEPER MSTR ENHANCED BY UPR DVGC AHEAD OF THIS FEATURE AS WELL AS WAA/ISENTROPIC ASCENT BEST SHOWN ON THE 290-300K SFCS /ABOUT H6-75/ AND SPREADING TO THE NE TOWARD THE WRN CWA. AHEAD OF THIS PCPN...SKIES OVER UPR MI ARE MAINLY CLDY WITH MOIST LLVL AIRMASS TRAPPED UNDER SHARP INVRN BASE ARND H9. THERE HAS BEEN SOME PATCHY LIGHT FREEZING DZ IN AREAS OVER THE KEWEENAW/NCENTRAL WHERE LLVL ESE FLOW UPSLOPES. MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON SN AMOUNTS ASSOCIATED WITH INCOMING SHRTWV AND GOING HEADLINES. LATE TODAY/TNGT...AS AREA OF ISENTROPIC ASCENT/UPR DVGC/DEEP LYR QVECTOR CNVGC IN ADVANCE OF SHRTWV MOVING THRU MN PUSHES INTO THE CWA...EXPECT SN TO OVERSPREAD THE AREA W-E. MODELS ARE INDICATING A 9-12 HR PERIOD OF FORCING BEFORE THE ARRIVAL OF SOME DEEP LYR QVECTOR DVGC/DNVA OVER THE W LATE IN THE WAKE OF THE SHRTWV/SFC LO MOVING OVER CENTRAL UPR MI/NRN LK SUP BY 12Z WED. BUT SOME LINGERING DRY AIR JUST ABOVE THE INVRN BASE WL HINDER THE DEVELOPMENT OF STEADIER PCPN...ESPECIALLY IN AREAS THAT EXPERIENCE A DOWNSLOPE WIND COMPONENT WITH ONGOING S FLOW...SO THE ACTUAL WINDOW FOR STEADIER SN WL ACTUALLY BE 6-9 HRS. MODELS INDICATE ABOUT 2.5 G/KG SPECIFIC HUMIDITY WL BE PRESENT ON THE 290K SFC ARND H7...WHICH WOULD SUPPORT GOING FCST UP 3 TO 4 INCHES OF SNOW DURING THE 6-9 HR WINDOW OF STEADY PCPN. ABSENCE OF ANY PHASING WITH THE ARCTIC/ SUBTROPICAL BRANCES AND SHARPER UPR DVGC ASSOCIATED WITH THE JET CORES IN THOSE BRANCHES AS WELL AS FCST HI THIN DGZ THAT WL LIMIT SN/WATER RATIOS WL LIMIT SN TOTALS. LATE TNGT...EXPECT THE PCPN OVER THE W TO DIMINISH FOR AT LEAST A TIME FOLLOWING THE EXIT OF THE DEEP UPR FORCING AND PASSAGE OF LO PRES TROF ACCOMPANYING SFC LO MOVING THRU NRN LK SUP. THE INCOMING AIRMASS WL BE INITIALLY TOO WARM TO SUPPORT LES. GOING HEADLINES APPEAR TO BE IN GOOD SHAPE. DID ADD LUCE COUNTY TO THE HEADLINE MIX WITH ARND 3 INCHES EXPECTED THERE BEFORE THE SN DIMINISHES LATER ON WED MRNG. WED...LINGERING STEADY SN OVER THE ERN CWA SHOULD END IN THE MRNG WITH THE PASSAGE OF SHRTWV/ACCOMPANYING SFC LO PRES TROF AND EXIT OF DEEP LYR QVECTOR CNVGC. GUIDANCE THEN SHOWS AN ARCTIC BRANCH SHRTWV DIGGING SHARPLY TO NEAR WRN LK SUP BY 00Z THU...WITH H85 TEMPS FALLING TOWARD -21C OVER THE NW CWA BY 00Z THU FOLLOWING ATTENDANT COLD FROPA. NNW H925 WINDS INCRSG UP TO 30-35KTS IN THE SHARP CYC FLOW LEFT IN THE WAKE OF THIS DISTURBANCE AND DEEPENING LO PRES EXITING TO THE E IN THE STRONG CAA WL RESULT IN VERY GUSTY SFC WINDS THAT WL AT LEAST APRCH ADVY LEVELS AS WELL AS CONSIDERABLE BLSN IN ADDITION TO THE LES IN EXPOSED AREAS NEAR LK SUP. THE COMBINATION OF THE SHARP CYC FLOW AS WELL AS SOME DPVA/DEEP LYR QVECTOR CNVGC/ DEEPENING MSTR WITH THE STRONG CAD MAY BRING A PERIOD OF SOME LK ENHANCED SN LATE IN THE DAY OVER THE W. LATER SHIFTS WL NEED TO INCLUDE ADDITIONAL HEADLINES FOR AT LEAST AREAS NEAR LK SUP FOR LATER WED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 348 PM EST TUE FEB 10 2015 STEADY N TO NNE WINDS WILL ALREADY BE SET UP AT 00Z THURSDAY...WITH THE SFC LOW OVER NE LAKE HURON. MUCH OF WEDNESDAY NIGHT WILL BE MARKED BY STRONG WINDS WITH GUSTS ON THE ORDER OF 30-40KTS. THERE IS A POCKET OF 35-40KT WINDS BETWEEN 925 AND 800MB FROM 00Z-12Z THURSDAY. THERE WILL DEFINETLY BE A NON-DIURNAL TREND TO THE WINDS. WINDS WILL REMAIN OUT OF THE N THROUGH 12Z SUNDAY...ALTHOUGH WEAKEN SIGNIFICANTLY LATE SATURDAY NIGHT/EARLY SUNDAY MONRING. IT WILL BE AN EXTENDED PERIOD OF LAKE EFFECT SNOW SHOWERS...THAT WHEN ACCOMPANIED WITH THE WIND AND THE SNOW ALREADY ON THE GROUND...WILL RESULT IN SHARPLY REDUCED VISIBILITIES. HEADLINES WILL EVENTUALLY BE POSTED FOR THIS PERIOD TO NOT ONLY HIGHLIGHT THE 2-4IN OF SNOW FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...BUT THE BLOWING SNOW SHARPLY REDUCING VIS. WILL CONTINUE TO HIGHLIGHT THIS PERIOD IN THE HWO...WITH THE MAIN FOCUS OF THE SNOW AND BLOWING SNOW BEING ALONG LAKE SUPERIOR...AND MAINLY FROM THE HURON MOUNTAINS THROUGH MUNISING AND GRAND MARIAS. BY DAYBREAK THURSDAY THE SFC WILL HAVE SHIFTED TO NY AND THE STRONG 1048-1052MB/30.9IN HIGH WILL HAVE SLIPPED INTO THE DAKOTAS. THE PRESSURE GRADIENT WILL WEAKEN DURING THE AFTERNOON HOURS AS THE HIGH WEAKENS SLIGHTLY ACROSS IA. EXPECT THE SFC RIDGE TO EXTEND DIRECTLY OVER THE CWA 00-06Z FRIDAY...BRINGING THE LIGHTEST WINDS OF THE PERIOD AND SHIFTING LINGERING LES OVER E ALGER AND SCHOOLCRAFT/W LUCE COUNTIES FROM LATE AFTERNOON THROUGH THE EVENING HOURS. OFFSHORE WINDS WILL TAKE HOLD ACROSS ALL OF N UPPER MI BY 12Z FRIDAY. QUICK ON THE HEALS OF THIS PAST SYSTEM...THE NEXT SFC LOW OVER THE W HALF OF ONTARIO AT 12Z FRIDAY SHOULD CROSS N/CENTRAL LAKE SUPERIOR BY MID DAY...AND DEEPEN OVER E LAKE SUPERIOR/UPPER MI BY 00Z SATURDAY. A LIMITED PERIOD OF WAA WILL MEAN THAT 850MB TEMPS WILL ONLY RISE TO AROUND -18C FRIDAY MORNING-EARLY AFTERNOON. AFTER THE PASSAGE OF THE LOW LOOK FOR THE -20 TO -25C 850MB AIR TO FILTER BACK IN. UNLIKE THE PAST COUPLE OF EVENTS...FREEZING DRIZZLE ON THE ONSET WILL NOT BE A CONCERN. NW WINDS WILL BE PICKING UP ACROSS THE W HALF OF UPPER MY BY AROUND 21Z...AND INCREASE ACROSS THE ENTIRE CWA OVERNIGHT TURNING FROM OUT OF THE NW TO N AS THE SFC LOW EXITS ACROSS LAKE HURON AND THE COLD AIR SETTLES IN WITH THE 500MB LOW OVER CENTRAL ONTARIO AT 06Z SATURDAY SINKING OVER CENTRAL/E UPPER MI AROUND 12Z. -25 TO -35C AIR WILL BE OVER THE W HALF BY 12Z SATURDAY /COLDEST OFF THE 10/12Z RUN OF THE GFS/. EXPECT COLD AND BLUSTERY CONDITIONS LATE FRIDAY NIGHT THROUGH SATURDAY! AS PREVIOUSLY STATED...THE FIRST WAVE OF LAKE EFFECT AND STRONG WINDS WEDNESDAY NIGHT AND THURSDAY WILL GIVE A GOOD FEEL TO WHAT WILL HAPPEN FRIDAY NIGHT INTO SATURDAY. AT THIS POINT EXPECT CONDITIONS TO BE WORSE THAN THE FIRST WAVE AND THERE WILL LIKELY BE A PERIOD OF BLIZZARD CONDITIONS FOR THE FAVORED MARQUETTE-MUNISING STRETCH AND PERSONS WILL LIKELY NEED TO PLAN FOR THE POSSIBILITY OF M-28 BEING CLOSED. WIND CHILL READINGS SATURDAY MORNING WILL FALL TO -15 TO -25F SATURDAY MORNING AS THE STRONG WINDS COMBINE WITH LOWS AROUND 0F. LOOK FOR SOME MODERATION TO THE VERY COLD AIR ALOFT SUNDAY...BUT STILL AROUND -20 TO -25C THROUGH THE DAY SUNDAY. THERE IS SOME DISCREPANCIES IN THE LOCAL WIND SHIFTS ACROSS LAKE SUPERIOR SUNDAY...BUT THE TREND WILL BE IMPROVING CONDITIONS EITHER WAY AS THE SFC HIGH SHIFTS OVERHEAD SUNDAY AND EXITS E SUNDAY AFTERNOON/EVENING. THE NEXT GOOD CHANCE OF SNOW FOR LATE MONDAY NIGHT/TUESDAY DOESN/T LOOK TOO IMPRESSIVE OFF THE ECMWF...BUT MORE DYNAMIC OFF THE GFS. A BLENDED MODEL SOLUTION SEEMS REASONABLE AT THIS POINT...AS THE MAIN CONCERS AND FOCUS FOR THIS FCST PERIOD ARE RIGHT AT THE BEGINING AND THEN FRIDAY NIGHT THROUGH SATURDAY MORNING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1157 PM EST TUE FEB 10 2015 AT KIWD/KCMX...EXPECT MVFR CONDITIONS TO GENERALLY BE THE RULE OVERNIGHT WITH OCNL -SN THAT MAY MIX AT TIMES WITH -FZDZ. WINDS WILL SHIFT TO AN UPSLOPE W FOLLOWING THE PASSAGE OF A LOW PRES TROF LATE IN THE NIGHT/EARLY MORNING...AND THIS SHOULD BRING A PERIOD OF IFR CONDITIONS. COLD FROPA AROUND MID MORNING WILL THEN BRING STRONGER NW WINDS/LAKE EFFECT SNOW...MAINTAINING IFR CONDITIONS. PASSAGE OF ANOTHER SFC TROF LATE IN THE AFTN/EARLY EVENING WILL INCREASE LES AND PROBABLY DROP CONDITIONS TO LIFR IN -SHSN/BLSN. AT KSAW...EXPECT MVFR CONDITIONS TO FALL TO IFR IN THE NEXT FEW HRS AS UPSLOPE S WIND CONTINUES. OCNL -SN MAY MIX AT TIMES WITH -FZDZ. CONDITIONS SHOULD RETURN TO MVFR WITH STRENGTHENING DOWNSLOPE W WIND VEERING NW FOLLOWING LOW PRES TROF PASSAGE EARLY THIS MORNING AND THEN COLD FROPA LATER IN THE MORNING. PASSAGE OF ANOTHER SFC TROF THIS EVENING WILL SIGNIFICANTLY INCREASE LAKE EFFECT SNOW/WINDS AND BLSN...RESULTING IN CONDITIONS FALLING TO LIFR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 348 PM EST TUE FEB 10 2015 THE GALE WATCH FOR WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING WILL BE UPGRADED TO A GALE WARNING. HEAVY FREEZING SPRAY WARNING WILL BE NEEDED. A RIDGE STRETCHING FROM JAMES BAY TO THE LOWER GREAT LAKES WILL SHIFT E ACROSS QUEBEC TONIGHT. MEANWHILE...A TROUGH ACROSS THE UPPER MS VALLEY WILL MOVE ACROSS LAKE SUPERIOR LATE TONIGHT AND WEDNESDAY MORNING. THE LOW WILL CONTINUE E ACROSS THE LOWER GREAT LAKES THROUGH WEDNESDAY NIGHT AS A TROUGH REMAINS ACROSS LOWER MI. A HIGH ACROSS S CENTRAL CANADA WEDNESDAY WILL MOVE TO THE MID MS VALLEY ON THURSDAY AND BUILD A RIDGE ACROSS LAKE SUPERIOR LATE THURSDAY INTO THURSDAY NIGHT. IN BETWEEN THE EXITING LOW AND NEARING HIGH...N GALES OF 35 TO 45 KNOTS ACROSS CENTRAL AND EASTERN LAKE SUPERIOR LATE WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. LOOK FOR A LOW ACROSS MANITOBA THURSDAY NIGHT TO SINK ACROSS LAKE SUPERIOR FRIDAY AFTERNOON AND EVENING...AND THE CENTRAL APPALACHIANS SATURDAY AFTERNOON...WHILE A LARGE HIGH NEARS FROM SOUTH CENTRAL CANADA AND THE NORTHERN PLAINS. THIS WILL BRING ABOUT ANOTHER ROUND OF N GALES OF 35 TO 45 KNOTS AND HEAVY FREEZING SPRAY IS POSSIBLE FRIDAY NIGHT THROUGH SATURDAY...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. EXPECT THE HIGH TO DRIFT ACROSS THE UPPER GREAT LAKES ON SUNDAY...WITH MUCH LIGHTER WINDS TAKING HOLD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ WEDNESDAY FOR MIZ001-003>006-010-011-013-014-084-085. WINTER WEATHER ADVISORY UNTIL 4 AM EST /3 AM CST/ WEDNESDAY FOR MIZ002-009. WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ267. GALE WARNING FROM 4 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ267. HEAVY FREEZING SPRAY WARNING FROM 1 PM WEDNESDAY TO 7 PM EST THURSDAY FOR LSZ266. GALE WARNING FROM 1 PM WEDNESDAY TO 4 PM EST THURSDAY FOR LSZ266. GALE WARNING FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ265. HEAVY FREEZING SPRAY WARNING FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ264. GALE WARNING FROM 1 PM WEDNESDAY TO 10 AM EST THURSDAY FOR LSZ264. HEAVY FREEZING SPRAY WARNING FROM 1 PM WEDNESDAY TO 7 AM EST THURSDAY FOR LSZ263. GALE WARNING FROM 1 PM WEDNESDAY TO 7 AM EST THURSDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
933 PM MST TUE FEB 10 2015 .UPDATE... JUST MADE SOME MINOR FORECAST ADJUSTMENTS THIS EVENING. RADAR SHOWED PRECIPITATION HAD JUST ABOUT EXITED THE SW PORTION OF THE REGION THIS EVENING...BUT JET FORCING AND WEAK WARM ADVECTION WERE CAUSING ADDITIONAL LIGHT SNOW SHOWERS TO DEVELOP IN N CENTRAL MT. THESE SNOW SHOWERS WERE MOVING S INTO THE FORECAST AREA. MODELS DRIED OUT THE REGION AFTER 06Z...THEN SHOWED SOME PRECIPITATION FORMING ALONG A SECONDARY SURGE OF COLDER AIR INTO THE NE PART OF THE AREA WED MORNING. ADJUSTED POPS THROUGH 06Z TO FIT RADAR TRENDS...THEN DRIED OUT 06-12Z. ON WED MORNING...SHIFTED THE LOW POPS FURTHER E TO COVER KBHK...BROADUS AND EKALAKA AND WENT WITH A SNOW/LIGHT FREEZING DRIZZLE MIX BASED ON RAP SOUNDINGS. SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOWED A GOOD DEAL OF LOW TO MID CLOUDS OVER THE AREA WHICH SHOULD KEEP FOG FROM DEVELOPING IN MOST AREAS. DID ADD PATCHY FOG TO JUDITH GAP WHERE RH WAS AT 100 PERCENT. TEMPERATURES AND WINDS WERE IN GOOD SHAPE. ARTHUR && .SHORT TERM...VALID FOR WED AND THU... COLDER AIR OVER EASTERN AND NORTHERN MONTANA PUSHING INTO SOUTH CENTRAL MONTANA BUT NORTHWEST FLOW ALOFT AND UNSTABLE CONDITIONS KEEPING THE AIRMASS MIXED AND TEMPERATURES ARE SLOW TO FALL. INSTABILITY BEING UNLEASHED BY THE LIFT FROM THE COLD AIR PUSH IS PRODUCING SHOWER ACTIVITY BUT RADAR IS SHOWING THIS PROCESS IT MOST INTENSE FOR THE BILLINGS AREA RIGHT NOW WITH KTFX RADAR SHOWING A DRYING TREND UPSTREAM. HAVE LOWERED POPS FOR THE EVENING BECAUSE ACTIVITY IS BEEN REALLY LIMITED IN COVERAGE SO FAR. ONLY EXPECT AN INCH IN THE FOOTHILLS WITH ONLY A BRIEF SNOW SHOWER OR SNOW PELLETS IN THE PLAINS EARLY THIS EVENING. THIS ACTIVITY WILL CONTINUE TO DECREASE OVERNIGHT BUT ENOUGH MOISTURE AROUND AS THE COLD AIR DEEPENS TO KEEP SOME FLURRIES AROUND. SECONDARY PUSH OF COLDER AIR INTO NORTHEAST MONTANA AND THE DAKOTAS ON WEDNESDAY WITH A WEAK BIT OF MID LEVEL WARM AIR ADVECTION WILL ALLOW THE AIRMASS TO STAY MOIST OVER AN AREA EAST OF BILLINGS OVER TO MILES CITY. THIS WILL ALLOW THE FLURRY ACTIVITY TO CONTINUE. FURTHER WEST THE AIRMASS STAYS DRIER BUT EASTERLY SURFACE WINDS WILL KEEP TEMPERATURES COOL...AT LEAST BY FEBRUARY 2015 STANDARDS. WEDNESDAY NIGHT THE COLD AIR RETREATS AND A SURFACE TROUGH FORMS ALONG THE FRONT RANGE OF THE ROCKIES AS THE RIDGE AXIS OVER THE PACIFIC NORTHWEST WEAKENS. THIS WILL ALLOW GAP FLOW WINDS TO BEGIN DEVELOPING FOR THE LIVINGSTON AND NYE AREAS BUT LACK OF MID LEVEL SUPPORT AND ONLY MODERATE PRESSURE GRADIENTS SHOULD LIMIT WIND SPEEDS SO DO NOT ANTICIPATE ADVISORY LEVEL WINDS AT THIS TIME. BY LATE WEDNESDAY NIGHT THIS SURFACE TROUGH BEGINS AN EASTWARD MIGRATION AND MODERATING DOWNSLOPE WINDS CAN BE EXPECTED IN THE CENTRAL ZONES. THE MOISTURE WHICH HAD BEEN SUPPORTING FLURRIES SHIFTS EASTWARD INTO THE DAKOTAS BRINGING AN END TO THE FLURRIES. THURSDAY WILL SEE TEMPERATURES RISE BUT SURFACE WINDS WILL BE NORTHWESTERLY AS MID LEVEL MOMENTUM MIXES DOWN. THIS WILL SUPPORT TEMPERATURES WELL INTO THE 50S ESPECIALLY AS CLOUD COVER DECREASES ALLOWING SOME DIURNAL WARMING. A LIGHT WESTERLY DOWNSLOPE CAN BE EXPECTED THURSDAY NIGHT AS STRONGER SURFACE HIGH PRESSURE FORMS OVER WESTERN MONTANA BUT GRADIENTS WILL BE FAIRLY LIGHT. LOOKS DRY WEDNESDAY NIGHT THROUGH THURSDAY NIGHT ACROSS THE AREA. BORSUM .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... EXTENDED PERIOD BEGINS FRIDAY WITH THE WESTERN US UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE. HIGHER HEIGHTS WILL BE ACTING TO KEEP TEMPERATURES FAIRLY WARM FOR MID FEBRUARY ACROSS THE CWA...WELL INTO THE UPPER 50S AT MOST LOCATIONS. BY SATURDAY...UPPER LEVEL ENERGY OFF THE WEST COAST WILL BREAK DOWN THE ENTRENCHED RIDGE AND USHER IN UNSETTLED NORTHWESTERLY FLOW. THERE IS A BIT OF MODEL UNCERTAINTY WITH THE SYSTEM EARLY NEXT WEEK...MAINLY IN THE FORM OF TEMPERATURES. IT WILL DEFINITELY BE COLDER THAN IT HAS BEEN WITH SOME SNOW...BUT TOO EARLY TO SAY JUST HOW COLD AND HOW MUCH. SINGER && .AVIATION... MVFR CONDITIONS WILL PREVAIL ACROSS CENTRAL AND EASTERN PORTIONS OF THE REGION INTO WEDNESDAY MORNING WITH LOW CEILINGS. OTHERWISE...VFR CONDITIONS WILL PREVAIL. FRIEDERS && .PRELIMINARY POINT TEMP/POPS... WED THU FRI SAT SUN MON TUE ----------------------------------------------------------- BIL 026/043 030/059 038/062 037/058 037/051 030/038 016/029 21/B 00/N 00/B 00/B 11/B 34/J 42/J LVM 030/052 036/056 039/061 040/058 037/053 031/041 018/033 20/B 00/N 11/B 11/B 01/B 44/W 42/J HDN 023/041 025/059 032/061 030/056 031/052 027/037 012/027 21/B 00/E 00/B 00/B 11/B 34/J 42/J MLS 018/030 018/051 029/053 024/044 029/046 025/032 010/023 02/J 00/E 00/B 01/E 11/B 23/J 32/J 4BQ 019/036 021/056 032/058 026/051 030/050 026/036 012/026 12/J 00/E 00/B 01/B 11/B 24/J 31/E BHK 013/027 010/046 027/048 016/034 024/043 022/030 006/021 12/J 00/E 00/B 01/E 11/N 23/J 31/B SHR 023/044 023/059 032/059 030/060 031/050 025/036 012/025 21/B 00/E 00/B 00/B 11/B 34/J 42/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1036 PM EST THU FEB 12 2015 .SYNOPSIS... ARCTIC AIR WILL POUR DOWN FROM CANADA TONIGHT, PRODUCING DANGEROUS WIND CHILLS OVERNIGHT INTO FRIDAY AFTERNOON. A STORM SYSTEM SLIDING OUT OF THE GREAT LAKES WILL BRING A FEW INCHES OF SNOW ON SATURDAY, WITH THE COLDEST AIR SO FAR THIS WINTER TO FOLLOW FOR SUNDAY. && .NEAR TERM /THROUGH FRIDAY/... 1030 PM UPDATE... DRY AIR HAS WEAKENED THE CENTRAL NY SNOW BAND FROM JUST A FEW HOURS AGO AND OUR FLOW IS FINALLY BECOMING MORE NORTHWEST. THE RESPONSE IS A SPRAY OF MULTI BAND LAKE SNOWS, EXTENDING ALL THE WAY INTO THE POCONOS OF NEPA. MAIN UPDATE WAS TO INCREASE SNOW AMOUNTS IN NEPA INTO THE DUSTING TO 2" RANGE. THE COMBINATION OF WIND AND SNOW WILL CONTINUE TO PRODUCE LOW VSBYS FOR THE NEXT FEW HOURS. USED A LAV/HRRR BLEND FOR TEMPS. WE ARE ALREADY AT ZERO HERE AT THE OFFICE, WITH SUSTAINED WINDS OF 20 MPH. WIND CHILL WARNING LOOKS GOOD. PREVIOUS AFD IS BELOW. 550 PM UPDATE... TEMP FORECAST ON TRACK WITH SINGLE NUMBERS ALREADY IN OUR FAR WEST. LATEST HRRR SEEMS TO HAVE A GREAT HANDLE ON FALLING TEMPS THIS EVENING, AND OUR CURRENT FORECAST MATCHES THIS VERY WELL. I DID TWEAK SNOW AMOUNTS AND POPS FOR THE NEXT FEW HOURS AS THE BAND OVER OSWEGO COUNTY HAS NOT MOVED AS FAR SOUTH AS ANTICIPATED. OVERALL A QUICK COATING TO AN INCH IS POSSIBLE OVER MUCH OF THE AREA THROUGH THIS EVENING AS COLDER AIR CONTINUES TO POUR INTO THE AREA, WITH ON AND OFF SNOW SQUALLS. WHILE AMOUNTS ARE NOT HIGH, SNOWFALL RATES AND INCREASING WIND WILL CREATE LOW VSBYS FROM TIME TO TIME. LOCALLY HIGHER AMOUNTS OF 2" TO 4" POSSIBLE ALONG THE SHORELINE OF ONEIDA LAKE IN PLACES LIKE SYLVAN BEACH, AND JEWELL, BUT THE HIGHER TOTALS WILL BE MORE IN OSWEGO COUNTY ITSELF. PREVIOUS AFD IS BELOW. 115 PM UPDATE... POWERFUL CAA WILL INCREASE THROUGH THE EVENING HOURS, WITH SURFACE TEMPERATURES EXPECTED TO FALL 10 TO 15 DEGREES IN JUST A MATTER OF A FEW HOURS. 925 MB TEMPS WILL FALL TO -21C AT BGM BY 6Z AND TO -24C BY 12Z. STRONG GRADIENT WILL KEEP WINDS BETWEEN 12 AND 18 MPH OVERNIGHT, WHILE GUSTS CONTINUE AROUND 25 MPH. THE COMBINATION OF WIND AND WELL BELOW TEMPERATURES WILL PRODUCE RARE WIND CHILL WARNING CRITERIA APPARENT TEMPERATURES...MAINLY BETWEEN -25F AND -30F. ADVISORY CRITERIA APPARENT TEMPERATURES SHOULD HOLD INTO FRIDAY AFTERNOON. 1055 AM UPDATE... WEAK CAA HAS BEGUN THROUGH THE FA. TEMPERATURES WILL HOLD STEADY OR SLIGHTLY FALL THROUGH THE NEXT 3 TO 5 HOURS. FAR MORE POWERFUL CAA WILL COMMENCE LATER THIS AFTERNOON AND ACCELERATE AFTER SUNSET. MADE MINOR ADJUSTMENTS TO TEMPERATURE TRENDS AND ALTERED THE GRIDDED POPS/WX BASED ON LATEST NAM12 PROGS. OTHERWISE THE FORECAST IS IN EXCELLENT SHAPE. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... 200 PM UPDATE... FRIGID APPARENT TEMPERATURES REMAIN IN PLACE THROUGH FRIDAY AFTERNOON. LIGHT LAKE EFFECT SNOW SHOWERS TO THE NORTH WILL TAPER OFF AS WINDS SHIFT AND DIRECTIONAL SHEAR INCREASES. ON SATURDAY, A POWERFUL CYCLONE WILL DROP OUT OF THE GREAT LAKES. GIVEN THE AMOUNT OF COLD AIR, IT SHOULD COME AS NO SURPRISE THAT THE SNOW GROWTH AREA IS MAXIMIZED. HOWEVER MOISTURE IS LIMITED, SO DESPITE THE STRENGTH OF THE STORM, WE ARE FORECASTING A BORDERLINE ADVISORY/NO-ADVISORY EVENT, WITH 3 TO 4 INCHES OF SNOW ACCUMULATION OVER AN 18 HOUR PERIOD. A STAGGERING AMOUNT OF ARCTIC AIR POURS DOWN BEHIND THE CYCLONE. AT THE SAME TIME, THE CYCLONE EXPLODES ALONG THE ATLANTIC COAST WHILE THE DOME OF HIGH PRESSURE SLIDES DOWN FROM THE UPPER MIDWEST. AS A RESULT, A STEEP PRESSURE GRADIENT WILL DEVELOP. THE COMBINATION OF FRIGID TEMPERATURES SATURDAY NIGHT INTO SUNDAY LOOKS QUITE DANGEROUS. APPARENT TEMPERATURES BELOW -30F ARE ANTICIPATED. 925MB TEMPS AT BGM ARE AROUND -23C ON SUNDAY, SO MOST AREAS WILL SEE MAX TEMPERATURES AROUND ZERO DEGREES. THE HILLTOPS AND THE NORTHERN FA WILL BE EVEN COLDER. 350 AM EST UPDATE... FRIDAY WILL FEEL MISERABLY COLD AS WELL AS 850MB TEMPS WILL ONLY MODERATE BY A COUPLE OF DEGREES. HIGH PRESSURE WILL BUILD OVER THE REGION ON FRI DURING THE DAY WHICH WILL PUT AN END TO LAKE EFFECT SHOWERS OVR NY. TEMPS FRIDAY AFTERNOON ARE EXPECTED TO RISE SLIGHTLY ABOVE ZERO. TEMPS LATE FRI NIGHT/SAT MORNING ARE EXPECTED TO BE VERY ALSO. MAY NEED TO ISSUE AN ADDITIONAL ADVISORY FOR THIS TIME FRAME... BUT WILL HOLD OFF FOR NOW. THE NEXT STORM SYSTEM WILL START TO IMPACT THE CWA SATURDAY MORNING. STRONG WAA WILL TAKE PLACE AHEAD OF THE SYSTEM RESULTING IN TEMPS RISING INTO THE LOW MID 20S. THIS SYSTEM MAY BRING WIDESPREAD SNOW TO THE CWA AND POSSIBLY ADVISORY SNOWFALL AMOUNTS. WILL KEEP CLOSE EYE ON EVOLUTION OF THIS STORM. THE COLD FRONT ATTENDANT WITH THIS SYSTEM WILL SURGE THROUGH THE CWA ON SUNDAY. THE AIRMASS BEHIND THIS SYSTEM WILL BE EVEN COLDER THAN THE AIRMASS EXPECTED TO MOVE THROUGH LATE TONIGHT. DANGEROUS WIND CHILL VALUES MAY BE LIKELY AGAIN LATE SAT NIGHT. WIND CHILL VALUES OF NEGATIVE 30 MAY BE POSSIBLE. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIPRES BLDS IN ON MON BRINGING AN END TO ANY LEFTOVER LE IN CNTRL NY. RDGG REMAINS IN CNTRL THRU TUE WITH A SLOW MODERATION IN TEMPS UNDER GNRLY CLR SKIES...ALTHOUGH BLO ZERO TEMPS STILL VERY PSBL OVERNIGHT. NEXT SYSTEM APRCHS FOR TUE AND WED WITH THE GFS AND EURO IN FAIR AGREEMENT. ESSENTIALLY A SRN STREAM WV GRABS GULF MOISTURE AND PHASES WITH A SHRT WV DROPPING SEWRD IN THE NRN STREAM TO DVLP A SIGNIFICANT SFC LOW OVER THE SE US LATE TUE AND EARLY WED. SYSTEM THEN RIDES THE SW FLOW TO A PSN NEAR JERSEY CST LTR WED. THIS BRINGS THE PSBLTY OF COASTAL RAIN BUT A MORE SIGNIFICANT SNOW INLAND AND OVER THE BGM FCST AREA LATE TUE INTO WED. MODEL DFRNCS INCLUDE THE USUAL SPEED ISSUES...AND THAT THE EURO SHOWS A WEAKER AND MORE SHEARED SFC LOW WHILE THE 12Z GFS SHOWS A MORE CONSOLIDATED LOW AND A STRONGER INV TROF BACK OVER THE FCST AREA. IN ANY EVENT...PLENTY OF TIME AND PLENTY TO WATCH FOR FOR THE NEXT STORM IN THE AREA. FLWD HPC GUID FOR TEMPS WHICH MATCHED WELL WITH THE PRVS FCST AND SURROUNDING OFFICES. FOR SOME REASON...HPC HAS BEEN DOWNPLAYING THE PTNL FOR LE IN THE WAKE OF THE WEEKEND SYSTEM SO HAVE BUMPED UP POPS FOR THAT PSBLTY. FLWD HPC MORE CLOSELY FOR THE APRCHG SYSTEM AT THE END OF THE PD. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... 00Z UPDATE... ARCTIC AIR IS POURING ACROSS THE REGION...WITH LAKE EFFECT CLOUDS AND OCCASIONAL -SHSN AND BLSN. KSYR-KBGM-KITH WILL BE MOST PRONE TO INTERMITTENT IFR VIS AND FUEL ALT CIGS FROM THOSE -SHSN TONIGHT...DUE TO LAKE ONTARIO MOISTURE AND EVENTUALLY A CAYUGA LAKE STREAMER AS WELL. A FEW LESS RESTRICTIVE FLURRIES WILL IMPACT THE OTHER TERMINALS AT TIMES AS WELL. WNW TO NW WINDS MID TEENS KTS...WITH SOME GUSTS INTO THE LOWER 20S KTS RANGE THIS EVENING...THEN BACKING OFF SOMEWHAT IN THE PREDAWN HOURS OF FRIDAY MORNING. SUSTAINED WINDS GENERALLY NW 10 KTS OR LESS DURING THE DAY FRIDAY. AS FLOW BACKS SOMEWHAT AFTERNOON-EARLY EVENING...LAKE ONTARIO MOISTURE WILL THROW SOME NEW -SHSN TOWARDS KSYR AND EVENTUALLY KRME...OTHERWISE ALL OTHER TERMINALS IMPROVE TO VFR. .OUTLOOK... FRI NGT...MAINLY VFR. SAT...RESTRICTIONS FROM -SHSN AND POSSIBLE SNOW SQUALLS. SUN...RESTRICTIONS POSSIBLE FROM -SHSN...MAINLY CNY. MON...MAINLY VFR. TUE...COASTAL LOW POSSIBLY PRODUCING -SN AND ASSOCIATED RESTRICTIONS ESPECIALLY LATE TUE-TUE NGT. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR PAZ038>040-043- 044-047-048-072. NY...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR NYZ009-015>018- 022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...DJP NEAR TERM...DJP/HEDEN SHORT TERM...DJP LONG TERM...DGM AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
658 PM EST THU FEB 12 2015 .SYNOPSIS... ARCTIC AIR WILL POUR DOWN FROM CANADA TONIGHT, PRODUCING DANGEROUS WIND CHILLS OVERNIGHT INTO FRIDAY AFTERNOON. A STORM SYSTEM SLIDING OUT OF THE GREAT LAKES WILL BRING A FEW INCHES OF SNOW ON SATURDAY, WITH THE COLDEST AIR SO FAR THIS WINTER TO FOLLOW FOR SUNDAY. && .NEAR TERM /THROUGH FRIDAY/... 550 PM UPDATE... TEMP FORECAST ON TRACK WITH SINGLE NUMBERS ALREADY IN OUR FAR WEST. LATEST HRRR SEEMS TO HAVE A GREAT HANDLE ON FALLING TEMPS THIS EVENING, AND OUR CURRENT FORECAST MATCHES THIS VERY WELL. I DID TWEAK SNOW AMOUNTS AND POPS FOR THE NEXT FEW HOURS AS THE BAND OVER OSWEGO COUNTY HAS NOT MOVED AS FAR SOUTH AS ANTICIPATED. OVERALL A QUICK COATING TO AN INCH IS POSSIBLE OVER MUCH OF THE AREA THROUGH THIS EVENING AS COLDER AIR CONTINUES TO POUR INTO THE AREA, WITH ON AND OFF SNOW SQUALLS. WHILE AMOUNTS ARE NOT HIGH, SNOWFALL RATES AND INCREASING WIND WILL CREATE LOW VSBYS FROM TIME TO TIME. LOCALLY HIGHER AMOUNTS OF 2" TO 4" POSSIBLE ALONG THE SHORELINE OF ONEIDA LAKE IN PLACES LIKE SYLVAN BEACH, AND JEWELL, BUT THE HIGHER TOTALS WILL BE MORE IN OSWEGO COUNTY ITSELF. PREVIOUS AFD IS BELOW. 115 PM UPDATE... POWERFUL CAA WILL INCREASE THROUGH THE EVENING HOURS, WITH SURFACE TEMPERATURES EXPECTED TO FALL 10 TO 15 DEGREES IN JUST A MATTER OF A FEW HOURS. 925 MB TEMPS WILL FALL TO -21C AT BGM BY 6Z AND TO -24C BY 12Z. STRONG GRADIENT WILL KEEP WINDS BETWEEN 12 AND 18 MPH OVERNIGHT, WHILE GUSTS CONTINUE AROUND 25 MPH. THE COMBINATION OF WIND AND WELL BELOW TEMPERATURES WILL PRODUCE RARE WIND CHILL WARNING CRITERIA APPARENT TEMPERATURES...MAINLY BETWEEN -25F AND -30F. ADVISORY CRITERIA APPARENT TEMPERATURES SHOULD HOLD INTO FRIDAY AFTERNOON. 1055 AM UPDATE... WEAK CAA HAS BEGUN THROUGH THE FA. TEMPERATURES WILL HOLD STEADY OR SLIGHTLY FALL THROUGH THE NEXT 3 TO 5 HOURS. FAR MORE POWERFUL CAA WILL COMMENCE LATER THIS AFTERNOON AND ACCELERATE AFTER SUNSET. MADE MINOR ADJUSTMENTS TO TEMPERATURE TRENDS AND ALTERED THE GRIDDED POPS/WX BASED ON LATEST NAM12 PROGS. OTHERWISE THE FORECAST IS IN EXCELLENT SHAPE. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... 200 PM UPDATE... FRIGID APPARENT TEMPERATURES REMAIN IN PLACE THROUGH FRIDAY AFTERNOON. LIGHT LAKE EFFECT SNOW SHOWERS TO THE NORTH WILL TAPER OFF AS WINDS SHIFT AND DIRECTIONAL SHEAR INCREASES. ON SATURDAY, A POWERFUL CYCLONE WILL DROP OUT OF THE GREAT LAKES. GIVEN THE AMOUNT OF COLD AIR, IT SHOULD COME AS NO SURPRISE THAT THE SNOW GROWTH AREA IS MAXIMIZED. HOWEVER MOISTURE IS LIMITED, SO DESPITE THE STRENGTH OF THE STORM, WE ARE FORECASTING A BORDERLINE ADVISORY/NO-ADVISORY EVENT, WITH 3 TO 4 INCHES OF SNOW ACCUMULATION OVER AN 18 HOUR PERIOD. A STAGGERING AMOUNT OF ARCTIC AIR POURS DOWN BEHIND THE CYCLONE. AT THE SAME TIME, THE CYCLONE EXPLODES ALONG THE ATLANTIC COAST WHILE THE DOME OF HIGH PRESSURE SLIDES DOWN FROM THE UPPER MIDWEST. AS A RESULT, A STEEP PRESSURE GRADIENT WILL DEVELOP. THE COMBINATION OF FRIGID TEMPERATURES SATURDAY NIGHT INTO SUNDAY LOOKS QUITE DANGEROUS. APPARENT TEMPERATURES BELOW -30F ARE ANTICIPATED. 925MB TEMPS AT BGM ARE AROUND -23C ON SUNDAY, SO MOST AREAS WILL SEE MAX TEMPERATURES AROUND ZERO DEGREES. THE HILLTOPS AND THE NORTHERN FA WILL BE EVEN COLDER. 350 AM EST UPDATE... FRIDAY WILL FEEL MISERABLY COLD AS WELL AS 850MB TEMPS WILL ONLY MODERATE BY A COUPLE OF DEGREES. HIGH PRESSURE WILL BUILD OVER THE REGION ON FRI DURING THE DAY WHICH WILL PUT AN END TO LAKE EFFECT SHOWERS OVR NY. TEMPS FRIDAY AFTERNOON ARE EXPECTED TO RISE SLIGHTLY ABOVE ZERO. TEMPS LATE FRI NIGHT/SAT MORNING ARE EXPECTED TO BE VERY ALSO. MAY NEED TO ISSUE AN ADDITIONAL ADVISORY FOR THIS TIME FRAME... BUT WILL HOLD OFF FOR NOW. THE NEXT STORM SYSTEM WILL START TO IMPACT THE CWA SATURDAY MORNING. STRONG WAA WILL TAKE PLACE AHEAD OF THE SYSTEM RESULTING IN TEMPS RISING INTO THE LOW MID 20S. THIS SYSTEM MAY BRING WIDESPREAD SNOW TO THE CWA AND POSSIBLY ADVISORY SNOWFALL AMOUNTS. WILL KEEP CLOSE EYE ON EVOLUTION OF THIS STORM. THE COLD FRONT ATTENDANT WITH THIS SYSTEM WILL SURGE THROUGH THE CWA ON SUNDAY. THE AIRMASS BEHIND THIS SYSTEM WILL BE EVEN COLDER THAN THE AIRMASS EXPECTED TO MOVE THROUGH LATE TONIGHT. DANGEROUS WIND CHILL VALUES MAY BE LIKELY AGAIN LATE SAT NIGHT. WIND CHILL VALUES OF NEGATIVE 30 MAY BE POSSIBLE. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIPRES BLDS IN ON MON BRINGING AN END TO ANY LEFTOVER LE IN CNTRL NY. RDGG REMAINS IN CNTRL THRU TUE WITH A SLOW MODERATION IN TEMPS UNDER GNRLY CLR SKIES...ALTHOUGH BLO ZERO TEMPS STILL VERY PSBL OVERNIGHT. NEXT SYSTEM APRCHS FOR TUE AND WED WITH THE GFS AND EURO IN FAIR AGREEMENT. ESSENTIALLY A SRN STREAM WV GRABS GULF MOISTURE AND PHASES WITH A SHRT WV DROPPING SEWRD IN THE NRN STREAM TO DVLP A SIGNIFICANT SFC LOW OVER THE SE US LATE TUE AND EARLY WED. SYSTEM THEN RIDES THE SW FLOW TO A PSN NEAR JERSEY CST LTR WED. THIS BRINGS THE PSBLTY OF COASTAL RAIN BUT A MORE SIGNIFICANT SNOW INLAND AND OVER THE BGM FCST AREA LATE TUE INTO WED. MODEL DFRNCS INCLUDE THE USUAL SPEED ISSUES...AND THAT THE EURO SHOWS A WEAKER AND MORE SHEARED SFC LOW WHILE THE 12Z GFS SHOWS A MORE CONSOLIDATED LOW AND A STRONGER INV TROF BACK OVER THE FCST AREA. IN ANY EVENT...PLENTY OF TIME AND PLENTY TO WATCH FOR FOR THE NEXT STORM IN THE AREA. FLWD HPC GUID FOR TEMPS WHICH MATCHED WELL WITH THE PRVS FCST AND SURROUNDING OFFICES. FOR SOME REASON...HPC HAS BEEN DOWNPLAYING THE PTNL FOR LE IN THE WAKE OF THE WEEKEND SYSTEM SO HAVE BUMPED UP POPS FOR THAT PSBLTY. FLWD HPC MORE CLOSELY FOR THE APRCHG SYSTEM AT THE END OF THE PD. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... 00Z UPDATE... ARCTIC AIR IS POURING ACROSS THE REGION...WITH LAKE EFFECT CLOUDS AND OCCASIONAL -SHSN AND BLSN. KSYR-KBGM-KITH WILL BE MOST PRONE TO INTERMITTENT IFR VIS AND FUEL ALT CIGS FROM THOSE -SHSN TONIGHT...DUE TO LAKE ONTARIO MOISTURE AND EVENTUALLY A CAYUGA LAKE STREAMER AS WELL. A FEW LESS RESTRICTIVE FLURRIES WILL IMPACT THE OTHER TERMINALS AT TIMES AS WELL. WNW TO NW WINDS MID TEENS KTS...WITH SOME GUSTS INTO THE LOWER 20S KTS RANGE THIS EVENING...THEN BACKING OFF SOMEWHAT IN THE PREDAWN HOURS OF FRIDAY MORNING. SUSTAINED WINDS GENERALLY NW 10 KTS OR LESS DURING THE DAY FRIDAY. AS FLOW BACKS SOMEWHAT AFTERNOON-EARLY EVENING...LAKE ONTARIO MOISTURE WILL THROW SOME NEW -SHSN TOWARDS KSYR AND EVENTUALLY KRME...OTHERWISE ALL OTHER TERMINALS IMPROVE TO VFR. .OUTLOOK... FRI NGT...MAINLY VFR. SAT...RESTRICTIONS FROM -SHSN AND POSSIBLE SNOW SQUALLS. SUN...RESTRICTIONS POSSIBLE FROM -SHSN...MAINLY CNY. MON...MAINLY VFR. TUE...COASTAL LOW POSSIBLY PRODUCING -SN AND ASSOCIATED RESTRICTIONS ESPECIALLY LATE TUE-TUE NGT. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR PAZ038>040-043- 044-047-048-072. NY...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR NYZ009-015>018- 022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...DJP NEAR TERM...DJP/HEDEN SHORT TERM...DJP LONG TERM...DGM AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
606 PM EST THU FEB 12 2015 .SYNOPSIS... ARCTIC AIR WILL POUR DOWN FROM CANADA TONIGHT, PRODUCING DANGEROUS WIND CHILLS OVERNIGHT INTO FRIDAY AFTERNOON. A STORM SYSTEM SLIDING OUT OF THE GREAT LAKES WILL BRING A FEW INCHES OF SNOW ON SATURDAY, WITH THE COLDEST AIR SO FAR THIS WINTER TO FOLLOW FOR SUNDAY. && .NEAR TERM /THROUGH FRIDAY/... 550 PM UPDATE... TEMP FORECAST ON TRACK WITH SINGLE NUMBERS ALREADY IN OUR FAR WEST. LATEST HRRR SEEMS TO HAVE A GREAT HANDLE ON FALLING TEMPS THIS EVENING, AND OUR CURRENT FORECAST MATCHES THIS VERY WELL. I DID TWEAK SNOW AMOUNTS AND POPS FOR THE NEXT FEW HOURS AS THE BAND OVER OSWEGO COUNTY HAS NOT MOVED AS FAR SOUTH AS ANTICIPATED. OVERALL A QUICK COATING TO AN INCH IS POSSIBLE OVER MUCH OF THE AREA THROUGH THIS EVENING AS COLDER AIR CONTINUES TO POUR INTO THE AREA, WITH ON AND OFF SNOW SQUALLS. WHILE AMOUNTS ARE NOT HIGH, SNOWFALL RATES AND INCREASING WIND WILL CREATE LOW VSBYS FROM TIME TO TIME. LOCALLY HIGHER AMOUNTS OF 2" TO 4" POSSIBLE ALONG THE SHORELINE OF ONEIDA LAKE IN PLACES LIKE SYLVAN BEACH, AND JEWELL, BUT THE HIGHER TOTALS WILL BE MORE IN OSWEGO COUNTY ITSELF. PREVIOUS AFD IS BELOW. 115 PM UPDATE... POWERFUL CAA WILL INCREASE THROUGH THE EVENING HOURS, WITH SURFACE TEMPERATURES EXPECTED TO FALL 10 TO 15 DEGREESS IN JUST A MATTER OF A FEW HOURS. 925 MB TEMPS WILL FALL TO -21C AT BGM BY 6Z AND TO -24C BY 12Z. STRONG GRADIENT WILL KEEP WINDS BETWEEN 12 AND 18 MPH OVERNIGHT, WHILE GUSTS CONTINUE AROUND 25 MPH. THE COMBINATION OF WIND AND WELL BELOW TEMPERATURES WILL PRODUCE RARE WIND CHILL WARNING CRITERIA APPARENT TEMPERATURES...MAINLY BETWEEN -25F AND -30F. ADVISORY CRITERIA APPARENT TEMPERATURES SHOULD HOLD INTO FRIDAY AFTERNOON. 1055 AM UPDATE... WEAK CAA HAS BEGUN THROUGH THE FA. TEMPERATURES WILL HOLD STEADY OR SLIGHTLY FALL THROUGH THE NEXT 3 TO 5 HOURS. FAR MORE POWERFUL CAA WILL COMMENCE LATER THIS AFTERNOON AND ACCELERATE AFTER SUNSET. MADE MINOR ADJUSTMENTS TO TEMPERATURE TRENDS AND ALTERED THE GRIDDED POPS/WX BASED ON LATEST NAM12 PROGS. OTHERWISE THE FORECAST IS IN EXCELLENT SHAPE. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... 200 PM UPDATE... FRIGID APPARENT TEMPERATURES REMAIN IN PLACE THROUGH FRIDAY AFTERNOON. LIGHT LAKE EFFECT SNOW SHOWERS TO THE NORTH WILL TAPER OFF AS WINDS SHIFT AND DIRECTIONAL SHEAR INCREASES. ON SATURDAY, A POWERFUL CYCLONE WILL DROP OUT OF THE GREAT LAKES. GIVEN THE AMOUNT OF COLD AIR, IT SHOULD COME AS NO SURPRISE THAT THE SNOW GROWTH AREA IS MAXIMIZED. HOWEVER MOISTURE IS LIMITED, SO DESPITE THE STRENGTH OF THE STORM, WE ARE FORECASTING A BORDERLINE ADVISORY/NO-ADVISORY EVENT, WITH 3 TO 4 INCHES OF SNOW ACCUMULATION OVER AN 18 HOUR PERIOD. A STAGGERING AMOUNT OF ARCTIC AIR POURS DOWN BEHIND THE CYCLONE. AT THE SAME TIME, THE CYCLONE EXPLODES ALONG THE ATLANTIC COAST WHILE THE DOME OF HIGH PRESSURE SLIDES DOWN FROM THE UPPER MIDWEST. AS A RESULT, A STEEP PRESSURE GRADIENT WILL DEVELOP. THE COMBINATION OF FRIGID TEMPERATURES SATURDAY NIGHT INTO SUNDAY LOOKS QUITE DANGEROUS. APPARENT TEMPERATURES BELOW -30F ARE ANTICIPATED. 925MB TEMPS AT BGM ARE AROUND -23C ON SUNDAY, SO MOST AREAS WILL SEE MAX TEMPERATURES AROUND ZERO DEGREES. THE HILLTOPS AND THE NORTHERN FA WILL BE EVEN COLDER. 350 AM EST UPDATE... FRIDAY WILL FEEL MISERABLY COLD AS WELL AS 850MB TEMPS WILL ONLY MODERATE BY A COUPLE OF DEGREES. HIGH PRESSURE WILL BUILD OVER THE REGION ON FRI DURING THE DAY WHICH WILL PUT AN END TO LAKE EFFECT SHOWERS OVR NY. TEMPS FRIDAY AFTERNOON ARE EXPECTED TO RISE SLIGHTLY ABOVE ZERO. TEMPS LATE FRI NIGHT/SAT MORNING ARE EXPECTED TO BE VERY ALSO. MAY NEED TO ISSUE AN ADDITIONAL ADVISORY FOR THIS TIME FRAME... BUT WILL HOLD OFF FOR NOW. THE NEXT STORM SYSTEM WILL START TO IMPACT THE CWA SATURDAY MORNING. STRONG WAA WILL TAKE PLACE AHEAD OF THE SYSTEM RESULTING IN TEMPS RISING INTO THE LOW MID 20S. THIS SYSTEM MAY BRING WIDESPREAD SNOW TO THE CWA AND POSSIBLY ADVISORY SNOWFALL AMOUNTS. WILL KEEP CLOSE EYE ON EVOLUTION OF THIS STORM. THE COLD FRONT ATTENDANT WITH THIS SYSTEM WILL SURGE THROUGH THE CWA ON SUNDAY. THE AIRMASS BEHIND THIS SYSTEM WILL BE EVEN COLDER THAN THE AIRMASS EXPECTED TO MOVE THROUGH LATE TONIGHT. DANGEROUS WIND CHILL VALUES MAY BE LIKELY AGAIN LATE SAT NIGHT. WIND CHILL VALUES OF NEGATIVE 30 MAY BE POSSIBLE. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIPRES BLDS IN ON MON BRINGING AN END TO ANY LEFTOVER LE IN CNTRL NY. RDGG REMAINS IN CNTRL THRU TUE WITH A SLOW MODERATION IN TEMPS UNDER GNRLY CLR SKIES...ALTHOUGH BLO ZERO TEMPS STILL VERY PSBL OVERNIGHT. NEXT SYSTEM APRCHS FOR TUE AND WED WITH THE GFS AND EURO IN FAIR AGREEMENT. ESSENTIALLY A SRN STREAM WV GRABS GULF MOISTURE AND PHASES WITH A SHRT WV DROPPING SEWRD IN THE NRN STREAM TO DVLP A SIGNIFICANT SFC LOW OVER THE SE US LATE TUE AND EARLY WED. SYSTEM THEN RIDES THE SW FLOW TO A PSN NEAR JERSEY CST LTR WED. THIS BRINGS THE PSBLTY OF COASTAL RAIN BUT A MORE SIGNIFICANT SNOW INLAND AND OVER THE BGM FCST AREA LATE TUE INTO WED. MODEL DFRNCS INCLUDE THE USUAL SPEED ISSUES...AND THAT THE EURO SHOWS A WEAKER AND MORE SHEARED SFC LOW WHILE THE 12Z GFS SHOWS A MORE CONSOLIDATED LOW AND A STRONGER INV TROF BACK OVER THE FCST AREA. IN ANY EVENT...PLNETY OF TIME AND PLENTY TO WATCH FOR FOR THE NEXT STORM IN THE AREA. FLWD HPC GUID FOR TEMPS WHICH MATCHED WELL WITH THE PRVS FCST AND SURROUNDING OFFICES. FOR SOME REASON...HPC HAS BEEN DOWNPLAYING THE PTNL FOR LE IN THE WAKE OF THE WEEKEND SYSTEM SO HAVE BUMPED UP POPS FOR THAT PSBLTY. FLWD HPC MORE CLOSELY FOR THE APRCHG SYSTEM AT THE END OF THE PD. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... ARCTIC FLOW ACROSS LAKE ONTARIO WILL PRODUCE A LE BAND INTO RME AND SYR THRU ABT 00Z REDUCING THE VSBY INTO THE IFR RANGE AT TIMES...WITH SOME MVFR CIGS AS WELL. ELSEWHERE...OCNL SHSN AND BLSN WILL BRING TEMP REDUCTIONS INTO THE MVFR RANGE. VERY COLD AIR AND DRY AIR LTR TNGT WILL LIMIT THE LE. LGTR WINDS WILL ALSO LIMIT THE BLSN SO VFR SHD DOMINATE...OTR THAN SOME MVFR CIGS AT TIMES. VFR CONDS CONT AFT 12Z FRI THRU THE END OF THE PD. .OUTLOOK... FRI NGT... MAINLY VFR. SAT...RESTRICTIONS POSSIBLE AREA-WIDE FROM -SN. SUN...RESTRICTIONS POSSIBLE FROM SHSN...MAINLY CNY. MON/TUE..MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR PAZ038>040-043- 044-047-048-072. NY...WIND CHILL WARNING UNTIL 4 PM EST FRIDAY FOR NYZ009-015>018- 022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...DJP NEAR TERM...DJP/HEDEN SHORT TERM...DJP LONG TERM...DGM AVIATION...DGM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
555 AM EST WED FEB 11 2015 .SYNOPSIS... DEEP LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL PULL SLOWLY AWAY FROM THE FORECAST AREA TODAY. COLD WEATHER TODAY WILL GIVE WAY TO A VERY BRIEF WARM-UP ON THURSDAY BEFORE THE NEXT ROUND OF ARCTIC AIR BEGINS TO ARRIVE EARLY THURSDAY EVENING...AND CONTINUING THROUGH EARLY FRIDAY. AN EVEN COLDER PUSH OF ARCTIC AIR WILL ARRIVE LATE SATURDAY NIGHT THROUGH SUNDAY. THE CHILL WILL ABATE ON MONDAY AND MAY GIVE WAY TO THE NEXT BONAFIDE CHANCE FOR PRECIPITATION ON TUESDAY OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM WEDNESDAY...POWERFUL LOW PRESSURE LOCATED SEVERAL HUNDRED MILES EAST OF THE OUTER BANKS WILL MOVE FARTHER AWAY FROM THE CAROLINAS TODAY. THIS WILL ALLOW A SHORTWAVE RIDGE AND A WEAK SURFACE RIDGE TO MOVE ACROSS THE AREA THIS EVENING. THERE IS ONE LAST PIECE OF THIS STORM TO DEAL WITH HOWEVER. A STRONG SUBSIDENCE INVERSION AROUND 925 MB (2500 FEET AGL) HAS TRAPPED ATLANTIC MOISTURE THROWN BACK AROUND THE STORM ACROSS EASTERN NORTH CAROLINA. THESE CLOUDS LOOK LIKE THEY WILL BE QUITE PERSISTENT... POTENTIALLY HANGING AROUND WILMINGTON THROUGH EARLY AFTERNOON BEFORE CLEARING FINALLY DEVELOPS. THE WESTERN EDGE OF THESE CLOUDS IS GOING TO BE VERY TOUGH TO PIN DOWN. THE LATEST RUC SHOWS CLOUDS CROSSING I-95 AND GOING AS FAR WEST AS DARLINGTON AND BENNETTSVILLE BEFORE STOPPING. (OTHER MODELS ARE NOT QUITE THIS FAR WEST.) GIVEN THE THIN VERTICAL DEPTH OF THE CLOUD DECK THE WESTERN EDGE SHOULD FRAGMENT THROUGH VERTICAL MIXING AND DRYING OF THE BOUNDARY LAYER FROM ALOFT A COUPLE HOURS AFTER SUNRISE...WITH THE EROSION THEN WORKING ITS WAY BACK EASTWARD TO THE COAST. WITH THE CLOUDS I HAVE ADJUSTED TEMPERATURES DOWNWARD ESPECIALLY IN THE BURGAW/WILMINGTON/SOUTHPORT AREA WITH UPPER 40S EXPECTED HERE. THE REMAINDER OF THE AREA SHOULD REACH 50-55... WARMEST WEST OF I-95 IN SOUTH CAROLINA. TONIGHT CLEAR SKIES ARE EXPECTED WITH CALM WINDS AND GOOD RADIATIONAL COOLING. LOWS SHOULD RANGE FROM THE LOWER TO MIDDLE 30S...COOLEST ACROSS INTERIOR SE NORTH CAROLINA. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...LONGWAVE PATTERN ALOFT TO REMAIN RELATIVELY UNCHANGED...WITH THE DEEP UPPER TROF AFFECTING THE EASTERN 1/3RD TO 1/2 OF THE UNITED STATES...AND UPPER RIDGING ACROSS THE WESTERN 1/3RD TO 1/2 OF THE UNITED STATES. SHORT WAVE TROFS OR VORTS ALOFT WILL BE ROTATING THRU THIS LONGWAVE UPPER TROF...KEEPING IT WELL AMPLIFIED DURING THIS TIME PERIOD. THE MEAN UPPER LONGWAVE TROF NORTH TO SOUTH AXIS IS PROGGED TO REMAIN EITHER OVERHEAD OR JUST OFF THE EAST COAST. WHAT THIS MEANS FOR THE ILM CWA IS FOR CONTINUED BELOW OR WELL BELOW NORMAL TEMPS...WITH ONLY A BRIEF WARM UP PRIOR TO THE PASSAGE OF THE NEXT UPPER S/W TROF... OR CLIPPER SINCE THEY ORIGINATE ACROSS WEST-CENTRAL CANADA. AS FOR THIS TIME PERIOD...A BRIEF WARM UP WILL OCCUR DURING DAYTIME THU AHEAD OF THE NEXT UPPER S/W TROF. THU MAXES MAY ACTUALLY REACH THE NORM FOR THIS TIME OF THE YEAR. THE MAIN DYNAMICS OF THIS UPPER S/W TROF TO REMAIN NORTH OF THE FA THU AFTN AND NIGHT...ALONG WITH THE SFC LOW THAT RE-DEVELOPS AND INTENSIFIES OFFSHORE FROM THE NEW ENGLAND COAST. ANY DEEP MOISTURE AVBL FOR PCPN OCCURRENCE TO REMAIN WELL NORTH OF THE FA. THE SHALLOW MOISTURE THAT WILL BE AVBL WILL BE USED FOR SCT/BKN CLOUDS AHEAD AND/OR ALONG THE SFC COLD FRONT. LATEST SREF ALSO INDICATES THAT NO MEASURABLE PCPN TO ACCOMPANY THIS CFP OR THERE- AFTER. DRYING OF THE ATM COLUMN AND EXCELLENT CAA OR ARCTIC AIR ADVECTION...UNDER GUSTY NW WINDS WILL OCCUR THU NIGHT INTO FRI AS THE SFC LOW NEARLY BOMBS WELL OFFSHORE FROM THE NEW ENGLAND COAST RESULTING IN A WELL TIGHTENED SFC PG ACROSS THE FA. AS FOR FRI INTO FRI NIGHT...THE CENTER OF THE ARCTIC HIGH WILL BE LOCATED OVER THE CENTRAL GULF COAST STATES AND THE BOMBING SFC LOW WILL BE MOVING THRU THE CANADIAN MARITIMES. AS FOR THE ILM CWA...THE BRUTAL WINDS WILL DIMINISH DURING FRI INTO FRI NIGHT. SKIES WILL REMAIN RELATIVELY CLEAR WITH A QUIET AND COLD FRI NIGHT ON TAP. OVERALL...USED THE NAM MOS GUIDANCE FOR THE NEAR TERM PERIOD ESPECIALLY WITH DAYTIME HIGHS. FOR EXAMPLE...A NEARLY 1 TO 2 CATEGORY DIFFERENCE EXISTS FOR THE NAM AND GFS MOS GUIDANCE FOR THU MAX TEMPS ACROSS THE ILM CWA. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY...FOR THIS UPCOMING WEEKEND THRU SUNDAY ...THE LONGWAVE PATTERN REMAINS RELATIVELY UNCHANGED. A WELL AMPLIFIED UPPER TROF AFFECTING ROUGHLY THE EASTERN 1/2 OF THE UNITED STATES...AND AMPLIFIED RIDGING ACROSS ROUGHLY THE WESTERN 1/2 OF THE UNITED STATES. IN FACT...THE MODELS ARE IN DECENT AGREEMENT IN AMPLIFYING THE EASTERN UPPER TROF TO THE POINT OF ALLOWING AND PUSHING LIFE THREATENING ARCTIC AIR DOWN THE EAST COAST INTO THE CAROLINAS LATE SATURDAY NIGHT THRU MONDAY MORNING. WHEN YOU SEE PROGGED 1000-500MB THICKNESSES APPROACHING 505 DECAMETERS AND 850 TEMPS PROGGED AT LESS THAN -20 DEGREES CELCIUS ACROSS THE ILM CWA DURING THE MENTIONED TIME PERIOD...WORD NEEDS TO GET OUT. OTHER THAN THE FORECAST ITSELF...WILL HIGHLIGHT THIS ARCTIC BLAST IN THE HWO AND LIKELY SUBSEQUENT STATEMENTS AS WE APPROACH THIS TIME PERIOD. THE GOOD THING THOUGH...IS NO FROZEN/FREEZING PCPN IS EXPECTED WHILE THIS AIRMASS IS IN PLACE ACROSS THE FA. FOR MON INTO TUE...THE AMPLIFIED LONGWAVE UPPER PATTERN LOOKS LIKE IT WANTS TO FLATTEN OUT SOME. WILL INDICATE SOME IMPROVING TEMPS FOR BOTH MON INTO TUE ALONG WITH THE NEXT BONAFIDE...ALBEIT A LOW CHANCE...FOR PCPN ACROSS THE FA. AT THIS POINT...NOT PUTTING TOO MUCH STOCK THIS FAR OUT IN TIME GIVEN THE CURRENT ACTIVE WX PATTERN. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...DEEP LOW PRESSURE WELL OFFSHORE HAS GIVEN US GUSTY NORTH WINDS ALL NIGHT...AND THIS WILL CONTINUE THROUGH THE MORNING HOURS UNTIL THE GRADIENT FINALLY WEAKENS THIS AFTERNOON. AN MVFR STRATOCU CEILING WILL AFFECT SOME OF THE TERMINALS THROUGH 14-15Z...AFTER WHICH IT WILL PROBABLY ERODE. WE ARE IN BETWEEN SYSTEMS TONIGHT...WITH LIGHT WINDS EXPECTED AND NEARLY CLEAR SKIES. EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM WEDNESDAY...A POWERFUL STORM CENTERED ALONG 70W OFF THE NORTH CAROLINA COASTLINE WILL MOVE FARTHER OUT TO SEA TODAY. THE BELT OF STRONGEST NORTHERLY WINDS SURROUNDING THIS STORM HAS ALREADY CLEARED THE COASTAL WATERS. FOR THIS REASON THE GALE WARNING HAS BEEN LOWERED TO A SMALL CRAFT ADVISORY. GRADUALLY DIMINISHING WIND SPEEDS ARE EXPECTED THROUGH THE DAY. BY TONIGHT WINDS WILL BE LIGHT FROM THE NW AS A TRANSITORY RIDGE MOVES ACROSS THE AREA. WINDS WILL THEN BACK AROUND TO THE SW OVERNIGHT BEHIND THE DEPARTING RIDGE. SEAS MAY TAKE SOME TIME TO DECAY AS AN EASTERLY BACKSWELL CONTINUES THROUGH TONIGHT. DOMINANT WAVE PERIODS OF 6 TO 7 SECONDS THIS MORNING WILL SHIFT TO 13 SECONDS THIS AFTERNOON AS THE BACKSWELL REPLACES LOCAL WIND WAVES AS THE PRIMARY WAVE TRAIN. WAVE PERIODS THIS LONG BEGIN TO "FEEL" BOTTOM IN WATER DEPTHS OF ~400 FEET...SO INSIDE THE COASTAL WATERS ZONES (0-20 MILES) SWELL HEIGHTS SHOULD DIMINISH SUBSTANTIALLY FROM THAT OBSERVED FARTHER OFFSHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...THU STARTS OUT DOCILE FOR BOTH WINDS AND SEAS ACROSS THE FA...BUT QUICKLY DETERIORATES DURING THE DAY AND CONTINUING ESPECIALLY THU NIGHT THRU MUCH OF DAYTIME FRI. THIS IN RESPONSE TO YET ANOTHER CLIPPER LOW THAT DIVES EAST-SOUTHEAST FROM CANADA TO OFF THE NJ-DEL COAST...THEN RAPIDLY INTENSIFIES OR NEARLY BOMBS OFF THE NEW ENGLAND COAST THU NIGHT INTO FRI...BEFORE SLOWLY MOVING NE TO THE CANADIAN MARITIMES BY LATE FRI. THE SFC COLD FRONT TO PUSH ACROSS THE ILM WATERS LATE THU AFTN OR EARLY EVENING. THE SFC PG WILL TIGHTEN DRAMATICALLY ACROSS THE AREA WATERS THU NITE INTO FRI...ACCOMPANIED BY EXCELLENT COLD AIR OR SHOULD I SAY ARCTIC AIR ADVECTION. SW-WSW WINDS THU AHEAD OF THE COLD FRONT...WILL VEER TO A GUSTY GALE FORCE NW WIND FOR THU NIGHT INTO EARLY FRI. A GALE WATCH LIKELY WILL BE NEEDED AT THE NEXT FULL UPDATE DURING WED. RIDGING FROM THE HIGHS CENTER WILL PUSH ACROSS THE LOCAL WATERS LATE FRI INTO FRI NIGHT ALLOWING BOTH WINDS AND SEAS TO RESPECTIVELY DIMINISH AND SUBSIDE. AM SOMEWHAT WORRIED THAT WAVEWATCH3 AND SWAN ARE NOT HANDLING THE BACK GROUND SWELL FROM THE DEEP LOW THAT IS CURRENTLY PULLING VERY SLOWLY TO THE EAST. MAY ACTUALLY GO ABOVE GUIDANCE FOR SIGNIFICANT SEAS DURING THU. THE WIND DRIVEN VARIETY WILL RULE SIG. SEAS COME THU NIGHT THRU FRI. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 330 AM WEDNESDAY...LOOKING AT THE NEXT CLIPPER LOW TO DIVE FURTHER SE THAN THE PREVIOUS ONE...REDEVELOPING OFF THE DELMARVA COAST LATE SATURDAY...THEN LIKELY BOMBING AS IT LIFTS NE TO OFF THE NEW ENGLAND COAST SUNDAY MORNING. ITS ASSOCIATED SFC COLD FRONT TO PUSH ACROSS THE LOCAL WATERS DURING SAT NIGHT. THE SFC PRESSURE GRADIENT WILL QUICKLY TIGHTEN ACROSS THE AREA WATERS SATURDAY NIGHT THRU SUNDAY...DUE TO THE COMBINED AFFECTS FROM A 1050MB SFC HIGH DROPPING OUT OF CANADA AND A SUB 970MB LOW MOVING NE OFF THE NEW ENGLAND COAST. ADD ARCTIC AIR ADVECTION TO THE MIX...AND YOU EASILY HAVE GALE FORCE WINDS LATER SAT NIGHT THRU SUNDAY. AS FOR SIGNIFICANT SEAS...WILL INITIALLY HAVE TO WATCH FOR ANY BACK GROUND SWELL ON SATURDAY EMANATING FROM THE INTENSE NORTH ATLANTIC LOWS. BUT FOR LATE SAT THRU SUNDAY...WIND DRIVEN WAVES FROM GALE FORCE WINDS WILL DOMINATE THE SIGNIFICANT SEAS. GALE WARNINGS WILL LIKELY BE NEEDED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250- 252. && $$ SYNOPSIS...DCH NEAR TERM...TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
348 AM EST WED FEB 11 2015 .SYNOPSIS... DEEP LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL PULL SLOWLY AWAY FROM THE FORECAST AREA TODAY. COLD WEATHER TODAY WILL GIVE WAY TO A VERY BRIEF WARM-UP ON THURSDAY BEFORE THE NEXT ROUND OF ARCTIC AIR BEGINS TO ARRIVE EARLY THURSDAY EVENING...AND CONTINUING THROUGH EARLY FRIDAY. AN EVEN COLDER PUSH OF ARCTIC AIR WILL ARRIVE LATE SATURDAY NIGHT THROUGH SUNDAY. THE CHILL WILL ABATE ON MONDAY AND MAY GIVE WAY TO THE NEXT BONAFIDE CHANCE FOR PRECIPITATION ON TUESDAY OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM WEDNESDAY...POWERFUL LOW PRESSURE LOCATED SEVERAL HUNDRED MILES EAST OF THE OUTER BANKS WILL MOVE FARTHER AWAY FROM THE CAROLINAS TODAY. THIS WILL ALLOW A SHORTWAVE RIDGE AND A WEAK SURFACE RIDGE TO MOVE ACROSS THE AREA THIS EVENING. THERE IS ONE LAST PIECE OF THIS STORM TO DEAL WITH HOWEVER. A STRONG SUBSIDENCE INVERSION AROUND 925 MB (2500 FEET AGL) HAS TRAPPED ATLANTIC MOISTURE THROWN BACK AROUND THE STORM ACROSS EASTERN NORTH CAROLINA. THESE CLOUDS LOOK LIKE THEY WILL BE QUITE PERSISTENT... POTENTIALLY HANGING AROUND WILMINGTON THROUGH EARLY AFTERNOON BEFORE CLEARING FINALLY DEVELOPS. THE WESTERN EDGE OF THESE CLOUDS IS GOING TO BE VERY TOUGH TO PIN DOWN. THE LATEST RUC SHOWS CLOUDS CROSSING I-95 AND GOING AS FAR WEST AS DARLINGTON AND BENNETTSVILLE BEFORE STOPPING. (OTHER MODELS ARE NOT QUITE THIS FAR WEST.) GIVEN THE THIN VERTICAL DEPTH OF THE CLOUD DECK THE WESTERN EDGE SHOULD FRAGMENT THROUGH VERTICAL MIXING AND DRYING OF THE BOUNDARY LAYER FROM ALOFT A COUPLE HOURS AFTER SUNRISE...WITH THE EROSION THEN WORKING ITS WAY BACK EASTWARD TO THE COAST. WITH THE CLOUDS I HAVE ADJUSTED TEMPERATURES DOWNWARD ESPECIALLY IN THE BURGAW/WILMINGTON/SOUTHPORT AREA WITH UPPER 40S EXPECTED HERE. THE REMAINDER OF THE AREA SHOULD REACH 50-55... WARMEST WEST OF I-95 IN SOUTH CAROLINA. TONIGHT CLEAR SKIES ARE EXPECTED WITH CALM WINDS AND GOOD RADIATIONAL COOLING. LOWS SHOULD RANGE FROM THE LOWER TO MIDDLE 30S...COOLEST ACROSS INTERIOR SE NORTH CAROLINA. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...LONGWAVE PATTERN ALOFT TO REMAIN RELATIVELY UNCHANGED...WITH THE DEEP UPPER TROF AFFECTING THE EASTERN 1/3RD TO 1/2 OF THE UNITED STATES...AND UPPER RIDGING ACROSS THE WESTERN 1/3RD TO 1/2 OF THE UNITED STATES. SHORT WAVE TROFS OR VORTS ALOFT WILL BE ROTATING THRU THIS LONGWAVE UPPER TROF...KEEPING IT WELL AMPLIFIED DURING THIS TIME PERIOD. THE MEAN UPPER LONGWAVE TROF NORTH TO SOUTH AXIS IS PROGGED TO REMAIN EITHER OVERHEAD OR JUST OFF THE EAST COAST. WHAT THIS MEANS FOR THE ILM CWA IS FOR CONTINUED BELOW OR WELL BELOW NORMAL TEMPS...WITH ONLY A BRIEF WARM UP PRIOR TO THE PASSAGE OF THE NEXT UPPER S/W TROF... OR CLIPPER SINCE THEY ORIGINATE ACROSS WEST-CENTRAL CANADA. AS FOR THIS TIME PERIOD...A BRIEF WARM UP WILL OCCUR DURING DAYTIME THU AHEAD OF THE NEXT UPPER S/W TROF. THU MAXES MAY ACTUALLY REACH THE NORM FOR THIS TIME OF THE YEAR. THE MAIN DYNAMICS OF THIS UPPER S/W TROF TO REMAIN NORTH OF THE FA THU AFTN AND NIGHT...ALONG WITH THE SFC LOW THAT RE-DEVELOPS AND INTENSIFIES OFFSHORE FROM THE NEW ENGLAND COAST. ANY DEEP MOISTURE AVBL FOR PCPN OCCURRENCE TO REMAIN WELL NORTH OF THE FA. THE SHALLOW MOISTURE THAT WILL BE AVBL WILL BE USED FOR SCT/BKN CLOUDS AHEAD AND/OR ALONG THE SFC COLD FRONT. LATEST SREF ALSO INDICATES THAT NO MEASURABLE PCPN TO ACCOMPANY THIS CFP OR THERE- AFTER. DRYING OF THE ATM COLUMN AND EXCELLENT CAA OR ARCTIC AIR ADVECTION...UNDER GUSTY NW WINDS WILL OCCUR THU NIGHT INTO FRI AS THE SFC LOW NEARLY BOMBS WELL OFFSHORE FROM THE NEW ENGLAND COAST RESULTING IN A WELL TIGHTENED SFC PG ACROSS THE FA. AS FOR FRI INTO FRI NIGHT...THE CENTER OF THE ARCTIC HIGH WILL BE LOCATED OVER THE CENTRAL GULF COAST STATES AND THE BOMBING SFC LOW WILL BE MOVING THRU THE CANADIAN MARITIMES. AS FOR THE ILM CWA...THE BRUTAL WINDS WILL DIMINISH DURING FRI INTO FRI NIGHT. SKIES WILL REMAIN RELATIVELY CLEAR WITH A QUIET AND COLD FRI NIGHT ON TAP. OVERALL...USED THE NAM MOS GUIDANCE FOR THE NEAR TERM PERIOD ESPECIALLY WITH DAYTIME HIGHS. FOR EXAMPLE...A NEARLY 1 TO 2 CATEGORY DIFFERENCE EXISTS FOR THE NAM AND GFS MOS GUIDANCE FOR THU MAX TEMPS ACROSS THE ILM CWA. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY... && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...STRATUS BASED AT 2000-2500 FEET AGL WILL AFFECT THE ILM AIRPORT THROUGH MID-TO-LATE LATE MORNING ACCORDING TO LATEST HIGH-RES MODELS AND EXTRAPOLATION OF NIGHTTIME SATELLITE IMAGERY. THIS IS THE BACK EDGE OF MOISTURE SWIRLING AROUND A POWERFUL LOW SEVERAL HUNDRED MILES OFF THE CAROLINA COAST. VFR CONDITIONS INLAND ARE EXPECTED THROUGH THE PERIOD...ALTHOUGH SCATTERED LOW STRATUS (2000 FT AGL) COULD PUSH INTO THE CRE AND LBT AIRPORTS TEMPORARILY THROUGH DAYBREAK. SURFACE WINDS NORTH 10 KNOTS ARE EXPECTED...EXCEPT NEAR ILM UNDER THE CLOUDS WHERE 10-15G25KT IS EXPECTED. SKIES SHOULD CLEAR EVEN AT ILM BY LATE MORNING WITH VFR CONDITIONS THIS AFTERNOON THROUGH TONIGHT. EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM WEDNESDAY...A POWERFUL STORM CENTERED ALONG 70W OFF THE NORTH CAROLINA COASTLINE WILL MOVE FARTHER OUT TO SEA TODAY. THE BELT OF STRONGEST NORTHERLY WINDS SURROUNDING THIS STORM HAS ALREADY CLEARED THE COASTAL WATERS. FOR THIS REASON THE GALE WARNING HAS BEEN LOWERED TO A SMALL CRAFT ADVISORY. GRADUALLY DIMINISHING WIND SPEEDS ARE EXPECTED THROUGH THE DAY. BY TONIGHT WINDS WILL BE LIGHT FROM THE NW AS A TRANSITORY RIDGE MOVES ACROSS THE AREA. WINDS WILL THEN BACK AROUND TO THE SW OVERNIGHT BEHIND THE DEPARTING RIDGE. SEAS MAY TAKE SOME TIME TO DECAY AS AN EASTERLY BACKSWELL CONTINUES THROUGH TONIGHT. DOMINANT WAVE PERIODS OF 6 TO 7 SECONDS THIS MORNING WILL SHIFT TO 13 SECONDS THIS AFTERNOON AS THE BACKSWELL REPLACES LOCAL WIND WAVES AS THE PRIMARY WAVE TRAIN. WAVE PERIODS THIS LONG BEGIN TO "FEEL" BOTTOM IN WATER DEPTHS OF ~400 FEET...SO INSIDE THE COASTAL WATERS ZONES (0-20 MILES) SWELL HEIGHTS SHOULD DIMINISH SUBSTANTIALLY FROM THAT OBSERVED FARTHER OFFSHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...THU STARTS OUT DOCILE FOR BOTH WINDS AND SEAS ACROSS THE FA...BUT QUICKLY DETERIORATES DURING THE DAY AND CONTINUING ESPECIALLY THU NIGHT THRU MUCH OF DAYTIME FRI. THIS IN RESPONSE TO YET ANOTHER CLIPPER LOW THAT DIVES EAST-SOUTHEAST FROM CANADA TO OFF THE NJ-DEL COAST...THEN RAPIDLY INTENSIFIES OR NEARLY BOMBS OFF THE NEW ENGLAND COAST THU NIGHT INTO FRI...BEFORE SLOWLY MOVING NE TO THE CANADIAN MARITIMES BY LATE FRI. THE SFC COLD FRONT TO PUSH ACROSS THE ILM WATERS LATE THU AFTN OR EARLY EVENING. THE SFC PG WILL TIGHTEN DRAMATICALLY ACROSS THE AREA WATERS THU NITE INTO FRI...ACCOMPANIED BY EXCELLENT COLD AIR OR SHOULD I SAY ARCTIC AIR ADVECTION. SW-WSW WINDS THU AHEAD OF THE COLD FRONT...WILL VEER TO A GUSTY GALE FORCE NW WIND FOR THU NIGHT INTO EARLY FRI. A GALE WATCH LIKLEY WILL BE NEEDED AT THE NEXT FULL UPDATE DURING WED. RIDGING FROM THE HIGHS CENTER WILL PUSH ACROSS THE LOCAL WATERS LATE FRI INTO FRI NIGHT ALLOWING BOTH WINDS AND SEAS TO RESPECTIVELY DIMINISH AND SUBSIDE. AM SOMEWHAT WORRIED THAT WAVEWATCH3 AND SWAN ARE NOT HANDLING THE BACK GROUND SWELL FROM THE DEEP LOW THAT IS CURRENTLY PULLING VERY SLOWLY TO THE EAST. MAY ACTUALLY GO ABOVE GUIDANCE FOR SIGNIFICANT SEAS DURING THU. THE WIND DRIVEN VARIETY WILL RULE SIG. SEAS COME THU NIGHT THRU FRI. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY... && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250- 252. && $$ SYNOPSIS...DCH NEAR TERM...TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...TRA/SGL MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1228 AM EST WED FEB 11 2015 .SYNOPSIS... STRONG LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL PULL SLOWLY AWAY FROM THE AREA TODAY. COOL WEATHER WILL GIVE WAY TO A VERY BRIEF WARMUP ON THURSDAY BEFORE ARCTIC AIR BEGINS TO ARRIVE THURSDAY EVENING. AN EVEN COLDER PUSH OF ARCTIC AIR WILL ARRIVE ON SUNDAY. THE CHILL WILL ABATE ON MONDAY AND MAY GIVE WAY TO SOME WET WEATHER TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 1230 AM WEDNESDAY...BASED ON LATEST RUC AND NAM MODELS PLUS EXTRAPOLATION OF SATELLITE TRENDS...SKY COVER HAS BEEN ADJUSTED UPWARDS ACROSS SE NORTH CAROLINA WHERE THE LOW STRATUS DECK WILL PERSIST THROUGH (AND PERHAPS BEYOND) DAYBREAK. THE BACK EDGE OF THIS STRATUS DECK MAY EVEN LUNGE WEST AS FAR AS LUMBERTON AND THE MYRTLE BEACH AREA BEFORE DAYBREAK ALTHOUGH THE ODDS OF ALL-OUT CLOUDY CONDITIONS ARE QUITE LOW THERE. MINOR ADJUSTMENTS UPWARD TO LOW TEMP AND WIND SPEED FORECASTS HAVE BEEN MADE FOR THE CLOUDIER AREAS WHERE RADIATIONAL COOLING WILL NOT OCCUR...LITTLE IF ANY CHANGES HAVE BEEN MADE ELSEWHERE. DISCUSSION FROM 1030 PM FOLLOWS... CLOUD COVER HAS BECOME VERY PATCHY WEST OF A LBT TO MYR LINE...WITH SKIES TOTALLY CLEAR FROM TIME TO TIME. THIS VERY SLOW EROSION OF THE THICK CLOUD COVER WILL SLOWLY EDGE OFFSHORE THROUGH THE NIGHT. LOW PRESSURE CONTINUES TO DEEPEN OFF THE COAST WITH LATEST ANALYSIS NOW SHOWING THE LOW UNDER 991 MB. COMBINATION OF STRENGTHENING LOW AND HIGH PRESSURE BUILDING SOUTH FROM EASTERN CANADA HAS PINCHED THE GRADIENT. BOTH THE SURFACE AND 500 MB LOW WILL PUSH FARTHER EAST TONIGHT... SLOWLY ALLOWING FOR INCREASED SUBSIDENCE AND AN EROSION OF THE CLOUD COVER FROM W AND S TO E AND N. FORECAST SOUNDINGS INDICATE PRECIPITABLE WATER VALUES DROPPING TO LESS THAN ONE-QUARTER OF AN INCH OVERNIGHT. SOME WRAP AROUND LOW-LEVEL MOISTURE MAY LINGER ALONG THE CAPE FEAR COAST WELL INTO THE NIGHT AND MOISTURE PROFILES AND SOME MOS GUIDANCE DO HINT AT THIS POSSIBILITY. WINDS WILL CONTINUE TO VERY SLOWLY DIMINISH AS THE TIGHTEST OF THE PRESSURE GRADIENT...ASSOCIATED WITH DEPARTING LOW PRESSURE...PULLS FURTHER N AND E. WIND SPEEDS INTO LATE EVE...IN THE 15 TO 25 MPH RANGE...WILL DECREASE TO 10 TO 15 MPH OVERNIGHT. COLD AIR ADVECTION WILL DICTATE TEMPS...WITH NO SIGNIFICANT RADIATIONAL COOLING...GIVEN THE BOUNDARY LAYER WILL NOT BE ABLE TO FULLY DECOUPLE...WE EXPECT WIDESPREAD LOWER 30S BY DAYBREAK. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...LINGERING MOISTURE ALONG THE COAST EARLY WEDNESDAY MORNING ASSOCIATED WITH LARGE SPINNING GYRE OVER THE WESTERN ATLANTIC. CLEARING SHOULD BE RAPID HOWEVER AS THE SYSTEM MOVES OFF THE NORTHEAST WHILE ALSO ENTRAINING DRY AIR ON ITS WESTERN PERIPHERY. THE SENSE OF LOW LEVEL TEMPERATURE ADVECTION WILL REMAIN WEAKLY COLD BUT THE RETURN OF SUNSHINE WILL FAVOR HIGHS 50-54. CLEAR SKIES REMAIN MOST OF WEDNESDAY NIGHT BUT THERE IS JUST ENOUGH WIND TO PRECLUDE RADIATIONAL COOLING OPTIMIZATION. THURSDAY FEATURES SUNSHINE FOR MOST OF THE DAY AND A PRE-FRONTAL SOUTHWESTERLY FLOW WILL BOOST HIGHS ABOVE 60. ARCTIC COLD FRONTAL PASSAGE LIKELY INDUCES EARLIER THAN NORMAL NON-DIURNAL TEMPERATURE DROPS LATE AFTERNOON AND EVENING ESPECIALLY INLAND ZONES. VERY STRONG TRAILING VORT MAX GLANCES BY TO OUR NORTH. IT SHOULD BE STRONG ENOUGH TO WRING OUT ANY REMAINING MOISTURE...SO LITTLE THAT PRECIPITATION WILL NOT BE MEASURABLE...BUT SHOULD TAKE THE FORM OF FLURRIES. WHAT FEW FLAKES DO FALL WILL BE MAINLY CONFINED TO BLADEN AND PENDER COUNTIES. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 300 PM TUESDAY...HIGH AMPLITUDE RIDGE IN THE WEST AND TROUGH IN THE EAST WILL PROVIDE AN AVENUE FOR COLD ARCTIC AIR TO RIDE DOWN INTO THE SOUTHEAST FRI THROUGH THE WEEKEND. AS COLD FRONT MOVES FARTHER OUT TO SEA AND HIGH PRESSURE BUILDS IN ON FRI EXPECT PLENTY OF COLD AND DRY AIR TO MOVE IN. 850 TEMPS WILL BE DOWN NEAR -8C AND EVEN WITH SUNSHINE...TEMPS WILL STRUGGLE TO MAKE IT TO 40. GUSTY NW WINDS WILL MAKE IT FEEL LIKE THE 30S FOR HIGH TEMPS. DEEP NW FLOW ON FRIDAY WILL BACK TOWARD THE WEST LATE FRI THROUGH SAT AS FLOW FLATTENS A BIT ON THE BOTTOM OF BROAD TROUGH IN THE EAST BEFORE NEXT SYSTEM BEGINS TO DIG DOWN FROM THE GREAT LAKES BY LATE SAT. WEAK HIGH PRESSURE AT THE SURFACE OVER THE OHIO VALLEY ON FRI WILL SHIFT EAST TOWARD THE COAST AND DISSIPATE AND OVERALL GRADIENT WILL RELAX SOME. THIS WILL ALLOW AIR MASS TO MODIFY SLIGHTLY FOR A BRIEF TIME TO ALLOW TEMPS TO REBOUND CLOSER TO 50 ON SATURDAY BUT NEXT SYSTEM WILL CARVE OUT THE TROUGH IN THE EAST BY LATE SAT AS ARCTIC FRONT DRAWS NEAR. THE FLOW ALOFT BASICALLY REMAINS W TO NW THROUGH THE WEEKEND...NOT TAPPING INTO ANY GULF MOISTURE OR WARM AIR AND ALTHOUGH THE DYNAMICS LOOK DECENT SAT NIGHT...THE AIR MASS REMAINS DRY AND THEREFORE NOT EXPECTING ANY PCP AND LIMITED...IF ANY CLOUDS WITH FRONTAL PASSAGE. THE ARCTIC BLAST BEHIND THE FRONT WILL WORK ITS WAY IN DURING VALENTINE`S EVENING IN GUSTY W-NW WINDS. 850 TEMPS THAT WERE ABLE TO WORK THEIR WAY BACK UP TO -3C WILL PLUMMET ONCE AGAIN POSSIBLY LOWER THAN -20 C AS H5 HEIGHTS DROP OUT TO 530 DEM WHICH...AS MENTIONED PREVIOUSLY...WILL BE ABOUT -3 STANDARD DEVIATIONS FROM CLIMO. OVERALL...EXPECT TEMPS TO STRUGGLE TO BREAK FREEZING WITH OVERNIGHT LOWS DOWN IN THE TEENS MOST PLACES SUN NIGHT AS CAA WANES AND RATIONAL COOLING EFFECTS TAKE OVER. THE GUSTY NW WINDS SUNDAY AFTN WILL MAKE IT FEEL LIKE THE 20S MOST PLACES. DEWPOINT TEMPS WILL BE BELOW 0 DEGREES F ON SUNDAY AFTN WITH THIS BITTER COLD AND DRY ARCTIC AIR MASS IN PLACE. DRY AND COLD ADVECTION WILL CONTINUE THROUGH MONDAY AS HIGH PRESSURE BUILDS DOWN FROM THE NW. WINDS WILL LIGHTEN AND AIR MASS WILL BEGIN TO MODIFY LATE MONDAY INTO TUES AS HIGH PRESSURE SHIFTS OFF SHORE AND WARMER AND MOISTER RETURN FLOW SETS UP AHEAD OF NEXT COLD FRONT SLATED TO CROSS THE AREA BY WED MORNING. PLENTY OF WAA WILL BRING TEMPS ABOVE FREEZING BY TUES MID MORNING AND THEREFORE WILL LEAVE OUT MENTION OF ANY MIXED PCP ALTHOUGH IT IS NOT OUT OF THE QUESTION BRIEFLY VERY EARLY TUES MORNING. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...STRATUS BASED AT 2000-2500 FEET AGL WILL AFFECT THE ILM AIRPORT THROUGH MID-TO-LATE LATE MORNING ACCORDING TO LATEST HIGH-RES MODELS AND EXTRAPOLATION OF NIGHTTIME SATELLITE IMAGERY. THIS IS THE BACK EDGE OF MOISTURE SWIRLING AROUND A POWERFUL LOW SEVERAL HUNDRED MILES OFF THE CAROLINA COAST. VFR CONDITIONS INLAND ARE EXPECTED THROUGH THE PERIOD...ALTHOUGH SCATTERED LOW STRATUS (2000 FT AGL) COULD PUSH INTO THE CRE AND LBT AIRPORTS TEMPORARILY THROUGH DAYBREAK. SURFACE WINDS NORTH 10 KNOTS ARE EXPECTED...EXCEPT NEAR ILM UNDER THE CLOUDS WHERE 10-15G25KT IS EXPECTED. SKIES SHOULD CLEAR EVEN AT ILM BY LATE MORNING WITH VFR CONDITIONS THIS AFTERNOON THROUGH TONIGHT. EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1230 AM WEDNESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST AT THIS TIME. PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS... A GALE WARNING CONTINUES AS LOW PRESSURE STRENGTHENS A LITTLE MORE AS IT PULLS SLOWLY AWAY FROM COASTAL NORTH CAROLINA OVERNIGHT. THE PRESSURE GRADIENT WILL FINALLY BEGIN TO RELAX WED MORNING AND THE GALE WARNING WILL LIKELY BE DOWNGRADED TO A SMALL CRAFT ADVISORY AT THAT TIME. A NORTH WIND OF 25 TO 35 KT HAS DRIVEN SEAS TO 5 TO 9 FT WITHIN 20 NM. SEAS AT THE FRYING PAN SHOALS BUOY HAVE BEEN AS HIGH AS 11 FT THIS EVE. ACROSS LONG BAY...WHERE A NORTH WIND GREATLY REDUCES THE FETCH...SEAS WERE LESS THAN 3 FT. SEAS WILL NOT BEGIN TO SIGNIFICANTLY SUBSIDE UNTIL AFTER SUNRISE WED. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...STILL A LITTLE TOUGH TO SAY AT WHAT SPEED CONDITIONS WILL IMPROVE ON WEDNESDAY AS THE AGITATED WINDS AND SEAS WILL BE ASSOCIATED WITH A VERY LARGE AND SLOW MOVING OCCLUDED STORM SYSTEM WELL OFFSHORE. SUCH SYSTEMS MOVEMENT IS NOT ALWAYS HANDLED SPECTACULARLY BY COMPUTER MODELS. IT WOULD SEEM THAT THERE MAY BE A LINGERING SMALL CRAFT ADVISORY FOR A TIME FOLLOWING THE LOWERING OF THE GALE WARNING. WINDS WILL GROW MUCH LIGHTER WEDNESDAY NIGHT AS THE STORM CONTINUES ITS SLOW EXIT. THE STORM WILL STILL BE VERY LARGE AND POWERFUL HOWEVER AND WILL STILL BE FLINGING CONSIDERABLE BACK SWELL ENERGY OUR WAY...SOME OF WHICH WILL BE WAVE SHADOWED BY CAPE HATTERAS. THIS BACKSWELL ABATES BY THURSDAY OVER THE 0-20 NM FCST ZONES BUT WILL STILL BE LURKING NOT TOO MUCH FARTHER OFFSHORE. THEN COMES AN AFTERNOON PASSAGE OF AN ARCTIC FRONT THAT WILL PUSH CONDITIONS BACK INTO SMALL CRAFT ADVISORY CRITERIA. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 300 PM TUESDAY...GUSTY NW WINDS TO START THE PERIOD WILL LIGHTEN AND BACK TO THE W THROUGH FRIDAY AS WEAK HIGH PRESSURE BUILDS IN. SEAS OF 3-6 FT FIRST THING FRIDAY WILL FALL QUICKLY TO AROUND 2 FT BY FRI NIGHT...BUT W TO SLIGHTLY SW WINDS WILL RISE ONCE AGAIN ON SATURDAY AHEAD OF THE NEXT COLD FRONT. THIS WILL PUSH SEAS UP TO 2 TO 4 AND CLOSER TO 3 TO 5 FT LATE SAT AFTN...BUT THE STRONGEST WINDS WILL OCCUR BEHIND THE COLD FRONT...WHEN NW WINDS WILL REACH AT LEAST 20-30 KTS. LOOKS LIKE POSSIBLE GALE WARNING MAY BE NEEDED FOR THESE STRONG WINDS SAT NIGHT INTO SUNDAY. SEAS WILL RISE RAPIDLY THROUGH SAT NIGHT WITH CURRENT WNA SHOWING WAVE HEIGHTS UP TO 10 FT IN THE OUTER WATERS SAT NIGHT. THE GREATEST SEAS WILL GET PUSHED WAY OUT WITH THIS VERY STRONG OFF SHORE FLOW THROUGH SUNDAY. THE ARCTIC AIR RUSHING OVER THE RELATIVELY WARMER OCEAN WATERS WILL KEEP A VERY WELL MIXED MARINE LAYER THROUGH SUN NIGHT BUT GRADIENT WINDS WILL WEAKEN SLOWLY ALLOWING SEAS TO DIMINISH BY MON MORNING. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...GALE WARNING UNTIL 5 AM EST WEDNESDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...RJD/TRA SHORT TERM...MBB LONG TERM...RGZ AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
932 PM CST THU FEB 12 2015 .UPDATE... ISSUED AT 924 PM CST THU FEB 12 2015 AT 9 PM CST CLOUDS HAVE CLEARED THROUGH A RUGBY TO STEELE TO WISHEK LINE THIS EVENING AS WARM ADVECTION ERODES AND TRANSLATES THE CLOUD DECK. EXPECT THE CLOUDS TO CLEAR JAMESTOWN BY 1 AM CST. SEEM TO BE ENOUGH MIXING IN THE BOUNDARY LAYER TO HOLD TEMPERATURES UP TONIGHT IN SPITE OF THE CLEARING. CURRENT FORECAST MINS LOOK OK. ADJUSTED CLOUDS TO FIT THE TREND. UPDATE ISSUED AT 627 PM CST THU FEB 12 2015 DECREASED POPS ACROSS THE SOUTHEAST AND DECREASED CLOUD COVER AS THE CLOUD DECK IS PUSHING SOUTHEAST FASTER THAN ORIGINALLY FORECAST. OTHERWISE FORECAST REMAINS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 400 PM CST THU FEB 12 2015 SNOW ENDING THIS EVENING SOUTHEAST AND LIGHT SNOW ON FRIDAY HIGHLIGHT THE SHORT TERM. LIGHT SNOW FOCUSED ACROSS THE JAMES RIVER VALLEY AS OF 2130 UTC WILL CONTINUE TO QUICKLY DIMINISH BY EARLY THIS EVENING BASED UPON RADAR TRENDS AND THE 19 UTC HRRR SIMULATED REFLECTIVITY. THE 12 AND INCOMING 18 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON A BAND OF LIGHT SNOW DEVELOPING ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA DURING THE DAY ON FRIDAY IN ASSOCIATION WITH THE BAROCLINIC ZONE ON THE LEADING EDGE OF THE NEXT ARCTIC HIGH THAT WILL PROPAGATE INTO THE NORTHERN PLAINS FRIDAY AFTERNOON AND EVENING. SNOWFALL AMOUNTS OF LESS THAN ONE INCH ARE EXPECTED. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 400 PM CST THU FEB 12 2015 A COLD FRONT IS EXPECTED TO SWING THROUGH THE AREA FRIDAY. SOME LIGHT SNOW IS POSSIBLE ALONG THE FRONT AS SURFACE LOW PRESSURE DEVELOPS ACROSS EASTERN MONTANA. COLD CANADIAN AIR WILL THEN FILTER INTO THE REGION FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER SATURDAY. THE LATEST 12 UTC MODELS CONTINUE THE TREND OF PREVIOUS RUNS...WITH A SHORTWAVE AND INVERTED TROUGH SLIDING THROUGH WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. WIDESPREAD SNOW AMOUNTS BETWEEN ONE AND FOUR INCHES APPEAR LIKELY BY SUNDAY EVENING. NORTHERN NORTH DAKOTA APPEARS TO BE FAVORED TO RECEIVE THE HIGHEST SNOWFALL TOTALS WITH THIS EVENT. SCATTERED SNOW COULD LINGER THROUGH MONDAY AS STRONG COLD AIR ADVECTION TAKES HOLD. THE ECMWF CONTINUES ITS DRY AND COLD FORECAST MONDAY NIGHT THROUGH WEDNESDAY. HOWEVER THE LATEST GFS RUN BRINGS A CLIPPER THROUGH NORTH DAKOTA WEDNESDAY AND PRODUCES SOME LIGHT SNOW. WIND CHILL HEADLINES MAY BE NEEDED MONDAY NIGHT AND TUESDAY NIGHT FOR AREAS EAST OF THE MISSOURI RIVER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 924 PM CST THU FEB 12 2015 AT 9 PM CST...WEAK HIGH PRESSURE EXTENDED ACROSS THE WESTERN DAKOTAS AS A TROUGH OF LOW PRESSURE WAS RETREATING THROUGH MINNESOTA. MVFR CLOUDS AT KJMS WILL CLEAR TO VFR AROUND 07Z. OTHERWISE VFR ACROSS THE REGION TONIGHT. THE NEXT WEATHER SYSTEM WILL SPREAD CLOUDS AND CHANCE FOR SNOW ACROSS WESTERN NORTH DAKOTA AFTER 18Z. SOME MVFR MAY RETURN ACROSS THE WEST AT THAT TIME. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...AJ AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
630 PM CST THU FEB 12 2015 .UPDATE... ISSUED AT 627 PM CST THU FEB 12 2015 DECREASED POPS ACROSS THE SOUTHEAST AND DECREASED CLOUD COVER AS THE CLOUD DECK IS PUSHING SOUTHEAST FASTER THAN ORIGINALLY FORECAST. OTHERWISE FORECAST REMAINS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 400 PM CST THU FEB 12 2015 SNOW ENDING THIS EVENING SOUTHEAST AND LIGHT SNOW ON FRIDAY HIGHLIGHT THE SHORT TERM. LIGHT SNOW FOCUSED ACROSS THE JAMES RIVER VALLEY AS OF 2130 UTC WILL CONTINUE TO QUICKLY DIMINISH BY EARLY THIS EVENING BASED UPON RADAR TRENDS AND THE 19 UTC HRRR SIMULATED REFLECTIVITY. THE 12 AND INCOMING 18 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON A BAND OF LIGHT SNOW DEVELOPING ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA DURING THE DAY ON FRIDAY IN ASSOCIATION WITH THE BAROCLINIC ZONE ON THE LEADING EDGE OF THE NEXT ARCTIC HIGH THAT WILL PROPAGATE INTO THE NORTHERN PLAINS FRIDAY AFTERNOON AND EVENING. SNOWFALL AMOUNTS OF LESS THAN ONE INCH ARE EXPECTED. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 400 PM CST THU FEB 12 2015 A COLD FRONT IS EXPECTED TO SWING THROUGH THE AREA FRIDAY. SOME LIGHT SNOW IS POSSIBLE ALONG THE FRONT AS SURFACE LOW PRESSURE DEVELOPS ACROSS EASTERN MONTANA. COLD CANADIAN AIR WILL THEN FILTER INTO THE REGION FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER SATURDAY. THE LATEST 12 UTC MODELS CONTINUE THE TREND OF PREVIOUS RUNS...WITH A SHORTWAVE AND INVERTED TROUGH SLIDING THROUGH WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. WIDESPREAD SNOW AMOUNTS BETWEEN ONE AND FOUR INCHES APPEAR LIKELY BY SUNDAY EVENING. NORTHERN NORTH DAKOTA APPEARS TO BE FAVORED TO RECEIVE THE HIGHEST SNOWFALL TOTALS WITH THIS EVENT. SCATTERED SNOW COULD LINGER THROUGH MONDAY AS STRONG COLD AIR ADVECTION TAKES HOLD. THE ECMWF CONTINUES ITS DRY AND COLD FORECAST MONDAY NIGHT THROUGH WEDNESDAY. HOWEVER THE LATEST GFS RUN BRINGS A CLIPPER THROUGH NORTH DAKOTA WEDNESDAY AND PRODUCES SOME LIGHT SNOW. WIND CHILL HEADLINES MAY BE NEEDED MONDAY NIGHT AND TUESDAY NIGHT FOR AREAS EAST OF THE MISSOURI RIVER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY) ISSUED AT 400 PM CST THU FEB 12 2015 MVFR STRATUS AND FLURRIES WILL CONTINUE ACROSS MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THIS AFTERNOON AND THROUGH THE NIGHT. A BAND OF LIGHT SNOW MAY IMPACT KISN/KMOT/KBIS/KJMS FRIDAY AFTERNOON WITH MVFR/IFR VISIBILITIES POSSIBLE. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MM SHORT TERM...AYD LONG TERM...AJ AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1205 PM CST WED FEB 11 2015 .UPDATE... ISSUED AT 1205 PM CST WED FEB 11 2015 UPDATE TO EXPAND THE FLURRY MENTION TO NEARLY ALL OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE AFTERNOON. OTHERWISE...THE FORECAST REMAINS ON TRACK AND BLENDED TO OBSERVED TRENDS THROUGH 18 UTC. UPDATE ISSUED AT 951 AM CST WED FEB 11 2015 OTHER THAN TO ADD A SCATTERED FLURRY MENTION UNDER THE STRATUS THIS MORNING PER SURFACE OBSERVATIONS...THE ONGOING FORECAST IS ON TRACK FOR TODAY AND TONIGHT. TEMPERATURES WILL SLOWLY FALL FROM MORNING HIGHS THE REMAINDER OF THE DAY AS COLD HIGH PRESSURE PROPAGATES INTO THE DAKOTAS. UPDATE ISSUED AT 641 AM CST WED FEB 11 2015 NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. THE CURRENT WIND CHILL HEADLINES LOOK GOOD FOR TONIGHT INTO THURSDAY MORNING. ONLY MADE MINOR ADJUSTMENTS TO THE HOURLY SENSIBLE WEATHER GRIDS. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CST WED FEB 11 2015 THE ISSUANCE OF A WIND CHILL ADVISORY IS THE MAIN HIGHLIGHT IN THE SHORT TERM PERIOD. A 1050MB SURFACE HIGH PRESSURE CURRENTLY OVER EAST CENTRAL ALBERTA WILL SLIDE SOUTHEAST TO NEAR REGINA BY 00Z THURSDAY...NEAR HARVEY AT 06Z THURSDAY...AND INTO CASSELTON BY 12Z THURSDAY. EXPECT A MOSTLY CLEAR SKY TO DEVELOP AS THE HIGH APPROACHES THIS AFTERNOON AND TONIGHT. SUB ZERO LOW TEMPERATURES AND WINDS TO 10 MPH WILL RESULT IN WIND CHILL TEMPERATURES TO 35 BELOW ZERO. A WIND CHILL ADVISORY HAS BEEN HOISTED TO REFLECT THIS. THE TURTLE MOUNTAINS WILL BE THE FIRST AREA TO DROP TO AROUND 25 BELOW BY MID AFTERNOON TODAY AND THUS HAVE DIVIDED THE ADVISORY OUT INTO TWO AREAS. THE TURTLE MOUNTAINS WILL BE VALID FROM 21Z WEDNESDAY THROUGH 18Z THURSDAY...AND REMAINING LOCALES ALONG AND EAST OF THE MISSOURI RIVER WILL HAVE A VALID TIME OF 00Z THURSDAY THROUGH 18Z THURSDAY. THE LATEST WATER VAPOR IMAGERY SHOWS A NORTHWEST FLOW INTO NORTH DAKOTA WITH ARCTIC AIR DESCENDING SOUTH FROM ALBERTA/SASKATCHEWAN. SUCCESSIVE BUT WEAK SHORTWAVES WITH MOSTLY CHANNELED VORTICITY POSE A SMALL THREAT FOR LIGHT SNOW IN SOUTHWEST NORTH DAKOTA TODAY. HIGH RESOLUTION HRRR AND RAP13 INDICATE THIS AND HAVE MAINTAINED THIS FEATURE FROM PREVIOUS FORECASTS. REGIONAL RADAR ALREADY PICKING UP ON WEAK REFLECTIVITY`S EMERGING OVER NORTH CENTRAL MONTANA. THE WINDOW OF OPPORTUNITY FOR LIGHT SNOW IS ROUGHLY FROM 14Z-20Z TODAY. ELSEWHERE THE FOG/STRATUS LOOP SHOWS A MOSTLY CLEAR SKY ACROSS THE NORTH CENTRAL WHICH IS WORKING TOWARD THE SOUTH CENTRAL AT THIS TIME. STILL POCKETS OF STRATUS UPSTREAM. BUFKIT SOUNDINGS THROUGHOUT THE UPCOMING MORNING MAINTAIN A MOIST BOUNDARY LAYER...AND ONCE MIXING DEVELOPS BY MID MORNING...EXPECT A PARTLY TO MOSTLY CLOUDY SKY TO ENSUE FOR A FEW HOURS. CONTINUED MIXING INTO THE AFTERNOON WILL EVENTUALLY LEAD TO LESS CLOUDS AS SUBSIDENCE AND DRIER AIR ALOFT GETS ENTRAINED AND LEADS TO CLEARING CONDITIONS. HENCE WHATEVER CLOUDS TO DEVELOP EARLY ON TODAY WILL DECREASE DURING THE MID TO LATE AFTERNOON. WARM AIR ADVECTION DEVELOPS WEST OF THE MISSOURI RIVER WEDNESDAY NIGHT LEADING TO RISING MOTION AND INCREASING CLOUDS IN THE WEST. THUS TEMPERATURES NOT QUITE AS COLD WITH MINIMUM TEMPERATURES REMAINING IN THE SINGLE DIGITS ABOVE ZERO WEST. OVERNIGHT LOWS ALONG AND EAST OF THE MISSOURI RIVER WILL RANGE FROM 10 TO 20 BELOW ZERO...AND AS MENTIONED ABOVE WIND CHILL TEMPERATURES TO 35 BELOW ZERO. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 AM CST WED FEB 11 2015 THE MEDIUM RANGE MODELS CAUGHT UP WITH THE ECMWF AND ARE NOW FORECASTING SNOW DEVELOPING AHEAD OF A WARM FRONT OVER WESTERN AND CENTRAL NORTH DAKOTA THURSDAY. INCREASED SNOW CHANCES MAINLY THURSDAY AFTERNOON AS A RESULT. NEW SNOW ACCUMULATIONS SHOULD REMAIN LESS THAN AN INCH. A DRY COLD FRONTAL PASSAGE IS THEN PROGGED FRIDAY. COLD CANADIAN AIR IS EXPECTED TO FILTER INTO THE REGION AGAIN FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER FRIDAY NIGHT. THE MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT FORECASTING A SHORTWAVE AND ITS ATTENDANT FRONT DIVING ACROSS WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. INCREASED THE CHANCES FOR SNOW GIVEN THE HIGHER CONFIDENCE WITH THE LATEST MODEL RUNS. SNOW ACCUMULATIONS LOOK TO BE MORE THAN PREVIOUSLY FORECAST AS WELL. WIDESPREAD AMOUNTS BETWEEN ONE AND THREE INCHES LOOK POSSIBLE. SNOW CHANCES WILL LINGER MONDAY AS A COLD FRONT IS PROGGED TO PUSH FROM NORTH TO SOUTH. HOWEVER...NEW ACCUMULATIONS APPEAR LIGHT. DRY AND COLD CONDITIONS ARE FORECAST MONDAY NIGHT THROUGH TUESDAY AS CANADIAN HIGH PRESSURE SETTLES ACROSS MONTANA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1205 PM CST WED FEB 11 2015 WIDESPREAD VFR TO MVFR STRATUS WITH SCATTERED LIGHT SNOW SHOWERS WILL DECREASE FROM NORTH TO SOUTH THROUGH THE AFTERNOON AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. BRIEF IFR CONDITIONS IN THE HEAVIER SNOW SHOWERS ARE POSSIBLE. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY FOR NDZ001>003-010>013-021>023-025-035>037-046>048-050-051. WIND CHILL ADVISORY UNTIL NOON CST THURSDAY FOR NDZ004-005. && $$ UPDATE...AYD SHORT TERM...KS LONG TERM...TM AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
951 AM CST WED FEB 11 2015 .UPDATE... ISSUED AT 951 AM CST WED FEB 11 2015 OTHER THAN TO ADD A SCATTERED FLURRY MENTION UNDER THE STRATUS THIS MORNING PER SURFACE OBSERVATIONS...THE ONGOING FORECAST IS ON TRACK FOR TODAY AND TONIGHT. TEMPERATURES WILL SLOWLY FALL FROM MORNING HIGHS THE REMAINDER OF THE DAY AS COLD HIGH PRESSURE PROPAGATES INTO THE DAKOTAS. UPDATE ISSUED AT 641 AM CST WED FEB 11 2015 NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. THE CURRENT WIND CHILL HEADLINES LOOK GOOD FOR TONIGHT INTO THURSDAY MORNING. ONLY MADE MINOR ADJUSTMENTS TO THE HOURLY SENSIBLE WEATHER GRIDS. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CST WED FEB 11 2015 THE ISSUANCE OF A WIND CHILL ADVISORY IS THE MAIN HIGHLIGHT IN THE SHORT TERM PERIOD. A 1050MB SURFACE HIGH PRESSURE CURRENTLY OVER EAST CENTRAL ALBERTA WILL SLIDE SOUTHEAST TO NEAR REGINA BY 00Z THURSDAY...NEAR HARVEY AT 06Z THURSDAY...AND INTO CASSELTON BY 12Z THURSDAY. EXPECT A MOSTLY CLEAR SKY TO DEVELOP AS THE HIGH APPROACHES THIS AFTERNOON AND TONIGHT. SUB ZERO LOW TEMPERATURES AND WINDS TO 10 MPH WILL RESULT IN WIND CHILL TEMPERATURES TO 35 BELOW ZERO. A WIND CHILL ADVISORY HAS BEEN HOISTED TO REFLECT THIS. THE TURTLE MOUNTAINS WILL BE THE FIRST AREA TO DROP TO AROUND 25 BELOW BY MID AFTERNOON TODAY AND THUS HAVE DIVIDED THE ADVISORY OUT INTO TWO AREAS. THE TURTLE MOUNTAINS WILL BE VALID FROM 21Z WEDNESDAY THROUGH 18Z THURSDAY...AND REMAINING LOCALES ALONG AND EAST OF THE MISSOURI RIVER WILL HAVE A VALID TIME OF 00Z THURSDAY THROUGH 18Z THURSDAY. THE LATEST WATER VAPOR IMAGERY SHOWS A NORTHWEST FLOW INTO NORTH DAKOTA WITH ARCTIC AIR DESCENDING SOUTH FROM ALBERTA/SASKATCHEWAN. SUCCESSIVE BUT WEAK SHORTWAVES WITH MOSTLY CHANNELED VORTICITY POSE A SMALL THREAT FOR LIGHT SNOW IN SOUTHWEST NORTH DAKOTA TODAY. HIGH RESOLUTION HRRR AND RAP13 INDICATE THIS AND HAVE MAINTAINED THIS FEATURE FROM PREVIOUS FORECASTS. REGIONAL RADAR ALREADY PICKING UP ON WEAK REFLECTIVITY`S EMERGING OVER NORTH CENTRAL MONTANA. THE WINDOW OF OPPORTUNITY FOR LIGHT SNOW IS ROUGHLY FROM 14Z-20Z TODAY. ELSEWHERE THE FOG/STRATUS LOOP SHOWS A MOSTLY CLEAR SKY ACROSS THE NORTH CENTRAL WHICH IS WORKING TOWARD THE SOUTH CENTRAL AT THIS TIME. STILL POCKETS OF STRATUS UPSTREAM. BUFKIT SOUNDINGS THROUGHOUT THE UPCOMING MORNING MAINTAIN A MOIST BOUNDARY LAYER...AND ONCE MIXING DEVELOPS BY MID MORNING...EXPECT A PARTLY TO MOSTLY CLOUDY SKY TO ENSUE FOR A FEW HOURS. CONTINUED MIXING INTO THE AFTERNOON WILL EVENTUALLY LEAD TO LESS CLOUDS AS SUBSIDENCE AND DRIER AIR ALOFT GETS ENTRAINED AND LEADS TO CLEARING CONDITIONS. HENCE WHATEVER CLOUDS TO DEVELOP EARLY ON TODAY WILL DECREASE DURING THE MID TO LATE AFTERNOON. WARM AIR ADVECTION DEVELOPS WEST OF THE MISSOURI RIVER WEDNESDAY NIGHT LEADING TO RISING MOTION AND INCREASING CLOUDS IN THE WEST. THUS TEMPERATURES NOT QUITE AS COLD WITH MINIMUM TEMPERATURES REMAINING IN THE SINGLE DIGITS ABOVE ZERO WEST. OVERNIGHT LOWS ALONG AND EAST OF THE MISSOURI RIVER WILL RANGE FROM 10 TO 20 BELOW ZERO...AND AS MENTIONED ABOVE WIND CHILL TEMPERATURES TO 35 BELOW ZERO. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 AM CST WED FEB 11 2015 THE MEDIUM RANGE MODELS CAUGHT UP WITH THE ECMWF AND ARE NOW FORECASTING SNOW DEVELOPING AHEAD OF A WARM FRONT OVER WESTERN AND CENTRAL NORTH DAKOTA THURSDAY. INCREASED SNOW CHANCES MAINLY THURSDAY AFTERNOON AS A RESULT. NEW SNOW ACCUMULATIONS SHOULD REMAIN LESS THAN AN INCH. A DRY COLD FRONTAL PASSAGE IS THEN PROGGED FRIDAY. COLD CANADIAN AIR IS EXPECTED TO FILTER INTO THE REGION AGAIN FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER FRIDAY NIGHT. THE MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT FORECASTING A SHORTWAVE AND ITS ATTENDANT FRONT DIVING ACROSS WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. INCREASED THE CHANCES FOR SNOW GIVEN THE HIGHER CONFIDENCE WITH THE LATEST MODEL RUNS. SNOW ACCUMULATIONS LOOK TO BE MORE THAN PREVIOUSLY FORECAST AS WELL. WIDESPREAD AMOUNTS BETWEEN ONE AND THREE INCHES LOOK POSSIBLE. SNOW CHANCES WILL LINGER MONDAY AS A COLD FRONT IS PROGGED TO PUSH FROM NORTH TO SOUTH. HOWEVER...NEW ACCUMULATIONS APPEAR LIGHT. DRY AND COLD CONDITIONS ARE FORECAST MONDAY NIGHT THROUGH TUESDAY AS CANADIAN HIGH PRESSURE SETTLES ACROSS MONTANA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY AFTERNOON) ISSUED AT 951 AM CST WED FEB 11 2015 MVFR/VFR STRATUS THIS MORNING ACROSS WESTERN AND CENTRAL NORTH DAKOTA WILL CLEAR THROUGH THE AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE AREA. BRIEF FLURRIES ARE POSSIBLE AT KMOT AND KJMS THIS MORNING. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY FOR NDZ001>003-010>013-021>023-025-035>037-046>048-050-051. WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST THURSDAY FOR NDZ004-005. && $$ UPDATE...AYD SHORT TERM...KS LONG TERM...TM AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
641 AM CST WED FEB 11 2015 .UPDATE... ISSUED AT 641 AM CST WED FEB 11 2015 NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. THE CURRENT WIND CHILL HEADLINES LOOK GOOD FOR TONIGHT INTO THURSDAY MORNING. ONLY MADE MINOR ADJUSTMENTS TO THE HOURLY SENSIBLE WEATHER GRIDS. THE UPDATED PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CST WED FEB 11 2015 THE ISSUANCE OF A WIND CHILL ADVISORY IS THE MAIN HIGHLIGHT IN THE SHORT TERM PERIOD. A 1050MB SURFACE HIGH PRESSURE CURRENTLY OVER EAST CENTRAL ALBERTA WILL SLIDE SOUTHEAST TO NEAR REGINA BY 00Z THURSDAY...NEAR HARVEY AT 06Z THURSDAY...AND INTO CASSELTON BY 12Z THURSDAY. EXPECT A MOSTLY CLEAR SKY TO DEVELOP AS THE HIGH APPROACHES THIS AFTERNOON AND TONIGHT. SUB ZERO LOW TEMPERATURES AND WINDS TO 10 MPH WILL RESULT IN WIND CHILL TEMPERATURES TO 35 BELOW ZERO. A WIND CHILL ADVISORY HAS BEEN HOISTED TO REFLECT THIS. THE TURTLE MOUNTAINS WILL BE THE FIRST AREA TO DROP TO AROUND 25 BELOW BY MID AFTERNOON TODAY AND THUS HAVE DIVIDED THE ADVISORY OUT INTO TWO AREAS. THE TURTLE MOUNTAINS WILL BE VALID FROM 21Z WEDNESDAY THROUGH 18Z THURSDAY...AND REMAINING LOCALES ALONG AND EAST OF THE MISSOURI RIVER WILL HAVE A VALID TIME OF 00Z THURSDAY THROUGH 18Z THURSDAY. THE LATEST WATER VAPOR IMAGERY SHOWS A NORTHWEST FLOW INTO NORTH DAKOTA WITH ARCTIC AIR DESCENDING SOUTH FROM ALBERTA/SASKATCHEWAN. SUCCESSIVE BUT WEAK SHORTWAVES WITH MOSTLY CHANNELED VORTICITY POSE A SMALL THREAT FOR LIGHT SNOW IN SOUTHWEST NORTH DAKOTA TODAY. HIGH RESOLUTION HRRR AND RAP13 INDICATE THIS AND HAVE MAINTAINED THIS FEATURE FROM PREVIOUS FORECASTS. REGIONAL RADAR ALREADY PICKING UP ON WEAK REFLECTIVITY`S EMERGING OVER NORTH CENTRAL MONTANA. THE WINDOW OF OPPORTUNITY FOR LIGHT SNOW IS ROUGHLY FROM 14Z-20Z TODAY. ELSEWHERE THE FOG/STRATUS LOOP SHOWS A MOSTLY CLEAR SKY ACROSS THE NORTH CENTRAL WHICH IS WORKING TOWARD THE SOUTH CENTRAL AT THIS TIME. STILL POCKETS OF STRATUS UPSTREAM. BUFKIT SOUNDINGS THROUGHOUT THE UPCOMING MORNING MAINTAIN A MOIST BOUNDARY LAYER...AND ONCE MIXING DEVELOPS BY MID MORNING...EXPECT A PARTLY TO MOSTLY CLOUDY SKY TO ENSUE FOR A FEW HOURS. CONTINUED MIXING INTO THE AFTERNOON WILL EVENTUALLY LEAD TO LESS CLOUDS AS SUBSIDENCE AND DRIER AIR ALOFT GETS ENTRAINED AND LEADS TO CLEARING CONDITIONS. HENCE WHATEVER CLOUDS TO DEVELOP EARLY ON TODAY WILL DECREASE DURING THE MID TO LATE AFTERNOON. WARM AIR ADVECTION DEVELOPS WEST OF THE MISSOURI RIVER WEDNESDAY NIGHT LEADING TO RISING MOTION AND INCREASING CLOUDS IN THE WEST. THUS TEMPERATURES NOT QUITE AS COLD WITH MINIMUM TEMPERATURES REMAINING IN THE SINGLE DIGITS ABOVE ZERO WEST. OVERNIGHT LOWS ALONG AND EAST OF THE MISSOURI RIVER WILL RANGE FROM 10 TO 20 BELOW ZERO...AND AS MENTIONED ABOVE WIND CHILL TEMPERATURES TO 35 BELOW ZERO. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 AM CST WED FEB 11 2015 THE MEDIUM RANGE MODELS CAUGHT UP WITH THE ECMWF AND ARE NOW FORECASTING SNOW DEVELOPING AHEAD OF A WARM FRONT OVER WESTERN AND CENTRAL NORTH DAKOTA THURSDAY. INCREASED SNOW CHANCES MAINLY THURSDAY AFTERNOON AS A RESULT. NEW SNOW ACCUMULATIONS SHOULD REMAIN LESS THAN AN INCH. A DRY COLD FRONTAL PASSAGE IS THEN PROGGED FRIDAY. COLD CANADIAN AIR IS EXPECTED TO FILTER INTO THE REGION AGAIN FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER FRIDAY NIGHT. THE MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT FORECASTING A SHORTWAVE AND ITS ATTENDANT FRONT DIVING ACROSS WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. INCREASED THE CHANCES FOR SNOW GIVEN THE HIGHER CONFIDENCE WITH THE LATEST MODEL RUNS. SNOW ACCUMULATIONS LOOK TO BE MORE THAN PREVIOUSLY FORECAST AS WELL. WIDESPREAD AMOUNTS BETWEEN ONE AND THREE INCHES LOOK POSSIBLE. SNOW CHANCES WILL LINGER MONDAY AS A COLD FRONT IS PROGGED TO PUSH FROM NORTH TO SOUTH. HOWEVER...NEW ACCUMULATIONS APPEAR LIGHT. DRY AND COLD CONDITIONS ARE FORECAST MONDAY NIGHT THROUGH TUESDAY AS CANADIAN HIGH PRESSURE SETTLES ACROSS MONTANA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 641 AM CST WED FEB 11 2015 THE LATEST SATELLITE IMAGERY SHOWS MOSTLY CLEAR CONDITIONS THROUGH CENTRAL NORTH DAKOTA...WHICH INCLUDES KMOT/KBIS/KJMS. EXPECT VFR CIGS THROUGH MID MORNING...FOLLOWED BY MVFR CIGS FROM 15Z-21Z. THE WESTERN TERMINALS OF KISN AND KDIK WILL REMAIN ON THE FRINGES OF MVFR AND VFR THROUGH MID TO LATE AFTERNOON. VFR CIGS ARE FORECAST TO RETURN TO ALL TERMINALS BETWEEN 21Z WEDS AND 00Z THURSDAY. CLOUDS INCREASE WEST...AT KISN AND KDIK AFTER MIDNIGHT...BUT STILL REMAIN IN VFR STRATUS UNTIL 12Z THURSDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY FOR NDZ001>003-010>013-021>023-025-035>037-046>048-050-051. WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST THURSDAY FOR NDZ004-005. && $$ UPDATE...TM SHORT TERM...KS LONG TERM...TM AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
305 AM CST WED FEB 11 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CST WED FEB 11 2015 THE ISSUANCE OF A WIND CHILL ADVISORY IS THE MAIN HIGHLIGHT IN THE SHORT TERM PERIOD. A 1050MB SURFACE HIGH PRESSURE CURRENTLY OVER EAST CENTRAL ALBERTA WILL SLIDE SOUTHEAST TO NEAR REGINA BY 00Z THURSDAY...NEAR HARVEY AT 06Z THURSDAY...AND INTO CASSELTON BY 12Z THURSDAY. EXPECT A MOSTLY CLEAR SKY TO DEVELOP AS THE HIGH APPROACHES THIS AFTERNOON AND TONIGHT. SUB ZERO LOW TEMPERATURES AND WINDS TO 10 MPH WILL RESULT IN WIND CHILL TEMPERATURES TO 35 BELOW ZERO. A WIND CHILL ADVISORY HAS BEEN HOISTED TO REFLECT THIS. THE TURTLE MOUNTAINS WILL BE THE FIRST AREA TO DROP TO AROUND 25 BELOW BY MID AFTERNOON TODAY AND THUS HAVE DIVIDED THE ADVISORY OUT INTO TWO AREAS. THE TURTLE MOUNTAINS WILL BE VALID FROM 21Z WEDNESDAY THROUGH 18Z THURSDAY...AND REMAINING LOCALES ALONG AND EAST OF THE MISSOURI RIVER WILL HAVE A VALID TIME OF 00Z THURSDAY THROUGH 18Z THURSDAY. THE LATEST WATER VAPOR IMAGERY SHOWS A NORTHWEST FLOW INTO NORTH DAKOTA WITH ARCTIC AIR DESCENDING SOUTH FROM ALBERTA/SASKATCHEWAN. SUCCESSIVE BUT WEAK SHORTWAVES WITH MOSTLY CHANNELED VORTICITY POSE A SMALL THREAT FOR LIGHT SNOW IN SOUTHWEST NORTH DAKOTA TODAY. HIGH RESOLUTION HRRR AND RAP13 INDICATE THIS AND HAVE MAINTAINED THIS FEATURE FROM PREVIOUS FORECASTS. REGIONAL RADAR ALREADY PICKING UP ON WEAK REFLECTIVITY`S EMERGING OVER NORTH CENTRAL MONTANA. THE WINDOW OF OPPORTUNITY FOR LIGHT SNOW IS ROUGHLY FROM 14Z-20Z TODAY. ELSEWHERE THE FOG/STRATUS LOOP SHOWS A MOSTLY CLEAR SKY ACROSS THE NORTH CENTRAL WHICH IS WORKING TOWARD THE SOUTH CENTRAL AT THIS TIME. STILL POCKETS OF STRATUS UPSTREAM. BUFKIT SOUNDINGS THROUGHOUT THE UPCOMING MORNING MAINTAIN A MOIST BOUNDARY LAYER...AND ONCE MIXING DEVELOPS BY MID MORNING...EXPECT A PARTLY TO MOSTLY CLOUDY SKY TO ENSUE FOR A FEW HOURS. CONTINUED MIXING INTO THE AFTERNOON WILL EVENTUALLY LEAD TO LESS CLOUDS AS SUBSIDENCE AND DRIER AIR ALOFT GETS ENTRAINED AND LEADS TO CLEARING CONDITIONS. HENCE WHATEVER CLOUDS TO DEVELOP EARLY ON TODAY WILL DECREASE DURING THE MID TO LATE AFTERNOON. WARM AIR ADVECTION DEVELOPS WEST OF THE MISSOURI RIVER WEDNESDAY NIGHT LEADING TO RISING MOTION AND INCREASING CLOUDS IN THE WEST. THUS TEMPERATURES NOT QUITE AS COLD WITH MINIMUM TEMPERATURES REMAINING IN THE SINGLE DIGITS ABOVE ZERO WEST. OVERNIGHT LOWS ALONG AND EAST OF THE MISSOURI RIVER WILL RANGE FROM 10 TO 20 BELOW ZERO...AND AS MENTIONED ABOVE WIND CHILL TEMPERATURES TO 35 BELOW ZERO. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 AM CST WED FEB 11 2015 THE MEDIUM RANGE MODELS CAUGHT UP WITH THE ECMWF AND ARE NOW FORECASTING SNOW DEVELOPING AHEAD OF A WARM FRONT OVER WESTERN AND CENTRAL NORTH DAKOTA THURSDAY. INCREASED SNOW CHANCES MAINLY THURSDAY AFTERNOON AS A RESULT. NEW SNOW ACCUMULATIONS SHOULD REMAIN LESS THAN AN INCH. A DRY COLD FRONTAL PASSAGE IS THEN PROGGED FRIDAY. COLD CANADIAN AIR IS EXPECTED TO FILTER INTO THE REGION AGAIN FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER FRIDAY NIGHT. THE MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT FORECASTING A SHORTWAVE AND ITS ATTENDANT FRONT DIVING ACROSS WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. INCREASED THE CHANCES FOR SNOW GIVEN THE HIGHER CONFIDENCE WITH THE LATEST MODEL RUNS. SNOW ACCUMULATIONS LOOK TO BE MORE THAN PREVIOUSLY FORECAST AS WELL. WIDESPREAD AMOUNTS BETWEEN ONE AND THREE INCHES LOOK POSSIBLE. SNOW CHANCES WILL LINGER MONDAY AS A COLD FRONT IS PROGGED TO PUSH FROM NORTH TO SOUTH. HOWEVER...NEW ACCUMULATIONS APPEAR LIGHT. DRY AND COLD CONDITIONS ARE FORECAST MONDAY NIGHT THROUGH TUESDAY AS CANADIAN HIGH PRESSURE SETTLES ACROSS MONTANA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 305 AM CST WED FEB 11 2015 LATEST SATELLITE IMAGERY SHOWS MOSTLY CLEAR CONDITIONS WORKING INTO NORTH CENTRAL NORTH DAKOTA/KMOT...AND SHIFTING SOUTH INTO KBIS AND KJMS. EXPECT MAINLY VFR CIGS THROUGH MID MORNING WITH POCKETS OF MVFR CIGS DEVELOPING FROM 15Z-21Z. THE WESTERN TERMINALS OF KISN AND KDIK WILL LIKELY REMAIN IN THE STRATUS THROUGH EARLY AFTERNOON. HOWEVER THE OVERALL TREND ACROSS WESTERN AND CENTRAL NORTH DAKOTA WILL BE FOR DECREASING CLOUDS WEDNESDAY AFTERNOON AND A RETURN TO VFR CONDITIONS BY 21Z AT ALL TERMINALS. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON CST THURSDAY FOR NDZ001>003-010>013-021>023-025-035>037-046>048-050-051. WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST THURSDAY FOR NDZ004-005. && $$ SHORT TERM...KS LONG TERM...TM AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1153 PM CST TUE FEB 10 2015 .UPDATE... ISSUED AT 1153 PM CST TUE FEB 10 2015 LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW CLOUDY CONDITIONS WITH POCKETS OF LIGHT SNOW SHOWERS ACROSS CENTRAL AND SOUTHERN NORTH DAKOTA. A POCKET OF CLEARING IS WORKING THROUGH THE NORTH CENTRAL AND WILL CONTINUE TO DIVE SOUTHEAST OVERNIGHT. WILL LET THE WIND ADVISORY EXPIRE IN THE JAMES RIVER VALLEY AS SCHEDULED AT MIDNIGHT TONIGHT. BRISK NORTHWEST WINDS WILL CONTINUE OVERNIGHT...BUT SUSTAINED WINDS OF 30 MPH WILL BE ISOLATED AT BEST AS THE MAXIMUM PRESSURE RISE BUBBLE SHIFTS FARTHER AWAY. LOOKING AHEAD...WIND CHILL TEMPERATURES TO 25 BELOW ZERO BEGIN TO EMERGE OVER THE TURTLE MOUNTAINS NEAR SUNRISE WEDNESDAY...AND THIS EXPAND ACROSS MOST OF NORTH CENTRAL AND INTO THE JAMES RIVER VALLEY WEDNESDAY NIGHT. WILL BE LOOKING AT POSSIBLE HEADLINES IN THE NEXT FORECAST ONCE ALL DATA IS ANALYZED AND POPULATED. UPDATE ISSUED AT 856 PM CST TUE FEB 10 2015 ALTHOUGH SOME ISOLATED GUSTS IN SIOUX AND BURLEIGH COUNTY REMAIN...THE WINDS ARE GENERALLY DIMINISHING SOUTH CENTRAL SO WILL ALLOW THE WIND ADVISORY TO EXPIRE THERE. ACROSS THE JAMES RIVER VALLEY OAKS IS GUSTING TO 48 MPH AT THIS TIME. WILL KEEP THE JAMES RIVER VALLEY PORTION GONG THROUGH EXPIRATION AT 06Z/MIDNIGHT CST. UPDATE ISSUED AT 551 PM CST TUE FEB 10 2015 LATEST WINDS AND WIND GUSTS NOW INCREASING ACROSS THE SOUTH CENTRAL AS THE FORECAST 3HR PRESSURE RISE MOVES ACROSS THIS AREA. CURRENT WIND ADVISORY IN PLACE FOR A LOW END ADVISORY. SATELLITE AND RADAR SHOW SOME BANDED SNOW SHOWERS THROUGH CENTRAL NORTH DAKOTA/ WILL AD 30 TO 50 CHANCE FOR SNOW MINOT TO BISMARCK TO JAMESTOWN FOR THIS THIS EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 320 PM CST TUE FEB 10 2015 STRONG WINDS AND FALLING TEMPERATURES HIGHLIGHT THE SHORT TERM FORECAST. AS A OF 20 UTC...A 5MB/3HR PRESSURE RISE BUBBLE WAS ANALYZED OVER LAKE SAKAKAWEA. THIS FEATURE WILL CONTINUE TO PROPAGATE SOUTHEAST THROUGH THE LATE AFTERNOON AND EARLY EVENING. WITH 35 TO 40 KTS TO MIX PER 19 UTC RAP SOUNDINGS...AND ISALLOBARIC FORCING FROM THE PRESSURE RISES...LOW END WIND ADVISORY CRITERIA GUSTS ARE EXPECTED INTO THE EARLY EVENING SOUTHWEST AND SOUTH CENTRAL. DID MAINTAIN A SLIGHT CHANCE FOR SNOW THROUGH THE EVENING AS WELL FOR MUCH OF WESTERN AND CENTRAL NORTH DAKOTA WITH LIGHT SNOW BEING OBSERVED AT MULTIPLE SITES ACROSS NORTH DAKOTA INTO SOUTHERN CANADA. FOR WEDNESDAY...COLD SURFACE HIGH PRESSURE WILL BUILD ACROSS NORTH DAKOTA. THIS WILL YIELD LITTLE TEMPERATURE RECOVERY FROM MORNING LOWS WITH CONTINUED COLD AIR ADVECTION THROUGH THE DAY. ADVISORY LEVEL WIND CHILLS MAY BE POSSIBLE ACROSS THE TURTLE MOUNTAINS BY LATE AFTERNOON. HOWEVER...WILL FORGO ANY ADVISORY FOR NOW. GIVEN GOOD AGREEMENT THROUGH THE PERIOD...A BLEND OF THE 12 UTC SUITE WAS USED FOR MOST FIELDS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 320 PM CST TUE FEB 10 2015 THE LONG TERM WILL BE CHARACTERIZED BY SEVERAL COLD BLASTS AND OCCASIONAL SNOW CHANCES. WEDNESDAY NIGHT INTO THURSDAY IS WHEN THE FIRST SUCH COLD BLAST ENTERS THE REGION. ARCTIC HIGH PRESSURE WILL SETTLE OVER NORTH DAKOTA THURSDAY MORNING. WITH CLEAR SKIES AND THE MAJORITY OF THE REGION UNDER AT LEAST A LIGHT BLANKET OF SNOW...TEMPERATURES SHOULD PLUMMET THURSDAY MORNING INTO THE TEENS AND POSSIBLY 20S BELOW ZERO EAST OF THE MISSOURI RIVER. SCATTERED LIGHT SNOW MAY FOLLOW THE HIGH PRESSURE AS AN UPPER LEVEL JET SHOULD BE IN A FAVORABLE POSITION FOR BROAD SCALE LIFT. THE NEXT BLAST ARRIVES SATURDAY...WHERE ONCE AGAIN TEMPERATURES SHOULD ONCE AGAIN FALL INTO THE TEENS BELOW ZERO. AND ONCE AGAIN SNOW WILL BE POSSIBLE FOLLOWING THE HIGH PRESSURE. HOWEVER...THE 12 UTC GFS AND ECMWF ARE MORE BULLISH WITH THIS EVENT AS A SURFACE LOW IS FORECAST TO DEVELOP ACROSS EASTERN MONTANA AND SLIDE SOUTHEAST THROUGH THE DAY SUNDAY. THERE IS THE POTENTIAL FOR MORE SIGNIFICANT ACCUMULATION WITH THIS EVENT AS THERE APPEARS TO BE FOCUSED LOW LEVEL ASCENT ALONG WITH THE UPPER LEVEL JET DYNAMICS. OTHERWISE...THE LONG TERM LOOKS DRY...WITH COLD TEMPERATURES EAST OF THE MISSOURI AND TEMPERATURES WEST OF THE MISSOURI RIVER LOOKING RATHER MILD...WITH READINGS IN THE 30S MOST DAYS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1153 PM CST TUE FEB 10 2015 LATEST SATELLITE IMAGERY SHOWS A STRATUS REGIME CONTINUING FOR MOST OF WESTERN AND CENTRAL NORTH DAKOTA. HOWEVER PARTIAL CLEARING IN THE NORTH CENTRAL HAS PUSHED INTO KMOT WITH VFR CONDITIONS. MAIN THEME FOR THIS TAF PERIOD WILL BE A MIX BETWEEN MVFR AND LOW VFR CIGS THROUGH WEDNESDAY MORNING...THEN A TREND TOWARD A CLEARING SKY WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ023-025-036-037- 047-048-050-051. && $$ UPDATE...KS SHORT TERM...AYD LONG TERM...AJ AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
105 AM EST WED FEB 11 2015 .SYNOPSIS... HIGH PRESSURE BUILDS IN OVERNIGHT. ARCTIC FRONTS CROSSES WEDNESDAY NIGHT AND AGAIN ON SATURDAY....AND MAYBE EVEN AGAIN NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 100 AM UPDATE... FCST ON TRACK. 900 PM UPDATE...NO SIGNIFICANT CHANGES MADE. DID ADJUST CLOUDS TONIGHT BASED ON CURRENT SATELLITE. PREVIOUS DISCUSSION... CURRENT SATELLITE IMAGERY SHOWS THE AREA BLANKETED BY LLVL STRATUS AIDED BY RESIDUAL MOISTURE FROM THE SFC LOW NOW PULLING AWAY FROM THE MID-ATLANTIC COAST. SOME CLEARING IS BEING OBSERVED IN THE FAR NW COUNTIES OF OUR CWA AS THE MOISTURE IS SLOWLY ERODED BY DRIER AIR FROM THE WEST. THE RAP HAS THE BEST HANDLE ON THIS...BUT THATS NOT SAYING MUCH. MOST GUIDANCE HAS BEEN TERRIBLE WITH RESPECT TO THE CLEARING OF THE LOW CLOUDS. MOISTURE IS EXPECTED TO HOLD LONGER IN THE MNTS...WHERE LOW CEILINGS WILL PERSIST UNTIL WED MORNING. RELATIVELY QUIET NIGHT ON TAP WITH CLOUD COVER CONTINUING TO ERODE AS THE UPPER RIDGE SETTLES IN. TEMPERATURES WILL REMAIN ON THE COOL SIDE TONIGHT AS WE DECOUPLE...BUT WAA BEGINS TO KICK FOR DAYBREAK AND MIXING WILL BRING WEDS TEMPS BACK UP INTO THE 40S FOR MOST LOCATIONS. FOR AS LONG AS IT TOOK THE SW RIDGE TO BUILD IN AND DRY THINGS OUT...IT UNFORTUNATELY WONT STAY LONG. THE FIRST IN A SERIES OF UPPER LEVEL WAVES WILL ARRIVE EARLY WEDS AFTERNOON...BRINGING MAINLY CLOUDS BACK TO THE AREA. AS THE UPPER LEVEL WAVE ARRIVES...IT DEAMPLIFIES AND THE FLOW ALOFT BECOMES MORE ZONAL. STILL...SOME WEAK MID-LEVEL CONVERGENCE EXISTS AHEAD OF THE FIRST WAVE AND MODELS HAVE CONSISTENTLY INCLUDED QPF WITH LIGHT SHOWERS WEDS EVENING. NOT SOLD ON THE IDEA...BUT WITH THIS FEATURE EVEN RESOLVED IN THE COARSER SUITE OF MODELS...THOUGHT IS WAS PRUDENT TO INTRODUCE SLIGHT CHC POPS. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... ACTIVE AND COLD WEATHER PATTERN REMAINS IN THE SHORT TERM AS A BARRAGE OF UPPER LEVEL WAVES WILL REINFORCE THE MEAN TROF IN THE EAST. ANOTHER WEAK WAVE WILL PASS JUST NORTH OF THE FORECAST AREA WEDS NIGHT AND AGAIN WILL DEAMPLIFY AS ON APPROACH. THIS DEAMPLIFICATION IS DUE TO THE THIRD AND BY FAR MOST VIGOROUS WAVE DROPPING IN QUICKLY BEHIND IT. EXPECT LIGHT RAIN CHANGING OVER TO LIGHT SNOW FOR MAINLY NRN PORTIONS OF THE CWA THROUGH THE PRE-DAWN HOURS THURS. AROUND DAWN THURS...CONDITIONS WILL DETERIORATE VERY QUICKLY. AS AN AMPLIFYING TROF DROPS THROUGH THE WRN GREAT LAKES AND TRIES TO CLOSE OFF AT 500MB. THIS WILL SEND A A VIGOROUS WAVE THROUGH THE FORECAST AREA...USHERING IN A COLD FRONT WITH A VASTLY DIFFERENT AIR MASS BEHIND IT. TEMPERATURES WILL FOLLOW A NON-DIURNAL CURVE WITH THURS HIGHS MORE THAN LIKELY REALIZED NEAR SUNRISE. ORIENTED ALONG THE COLD FRONT...SNOW SHOWERS WILL OVERTAKE THE REGION FROM W TO E QUICKLY DURING THE DAYLIGHT HOURS THURS. BEHIND THE COLD FRONT...850MB TEMPS WILL DROP SHARPLY INTO THE -10 TO -15C RANGE ALLOWING CRYSTAL GROWTH TO BE MAXIMIZED. WITH LAPSE RATES STEEPENING...CONVECTIVE SNOW SQUALLS WILL PERSIST THROUGH THURS EVENING. THE BTV SNOW SQUALL PARAMETER DRIVEN BY THE 12Z NAM DATA SHOWS A BULLSEYE OF GREATER THAN 4 FOR MUCH OF THE AFTERNOON THURS...FURTHER DIAGNOSING A PRIME SET UP FOR SNOW SQUALLS TO EXIST. MOISTURE IS DRIVEN INTO THE MOUNTAINS THROUGH THURS NIGHT...AND SNOW SHOWERS SHOULD PERSIST THERE THROUGH MIDNIGHT THURS. ELSEWHERE...THE MOISTURE QUICKLY DRIES UP...BUT THE AIRMASS IS COLD ENOUGH THAT LIGHT SNOW SHOWERS OR FLURRIES COULD PERSIST THROUGH LATE THURS EVENING. EXPECT MOUNTAINOUS LOCATIONS TO BE IN THE SINGLE DIGITS TO BELOW ZERO...AS WELL AS SINGLE DIGITS IN SOUTHEAST OHIO FRIDAY MORNING. ADDING TO THIS IS THE STRONG...GUSTY WINDS THAT WILL DRIVE WIND CHILLS TO NEAR 0 ACROSS THE LOWLANDS AND WELL BELOW 0 IN THE MOUNTAINS. STILL EXPECTING WIND CHILL ADVISORY CRITERIA TO BE MET ACROSS MUCH OF THE MOUNTAINOUS COUNTIES AND PARTS OF NORTHERN WV. WILL CONTINUE TO HIGHLIGHT IN THE HWO. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MEAN TROF PERSISTS ACROSS THE ERN CONUS THROUGH THE EXTENDED PERIOD KEEPING A PROLONGED COLD AND DISTURBED WEATHER PATTERN. BRIEF SFC HIGH FRI WILL BE FOLLOWED QUICKLY BY YET ANOTHER VERY STRONG CLOSED UPPER LOW THIS WEEKEND. THIS WILL ONCE AGAIN REINFORCE THE COLD AIR...BRINGING THE COLDEST TEMPERATURES OF THE WEEK TO OUR AREA. MORE LIGHT SNOW IS EXPECTED THROUGH THE WEEKEND...BUT THE MAIN STORY LINE WILL BE THE COLD TEMPERATURES. NEXT WEEK BEGINS WITH A VERY BRIEF SPELL OF ZONAL FLOW ALOFT AND TEMPERATURE MODERATION BEFORE YET ANOTHER INTRUSION OF ARCTIC AIR. MAINLY FOLLOW WPC FOR WEATHER VARIABLES IN THE EXTENDED...WITH CONSIDERABLE MODEL AGREEMENT BETWEEN THE GFS/ECMWF. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... MOIST LOW LEVEL NRLY FLOW CONTINUES ON BACK SIDE OF LOW PRESSURE MOVING OFF THE E COAST. THIS HAS THE MOUNTAINS SOCKED IN IN IFR BOTH EKN AND BKW ON OR SOON TO BE ON BOTH CIGS AND VSBYS. HIGH PRESSURE BUILDING IN TOWARD DAWN WILL CAUSE THE FLOW TO DIMINISH...WHICH OF COURSE DOES NOTHING TO SCOUR OUT THE LOW LEVEL MOISTURE. AS SUCH...IT WILL TAKE POST DAY BREAK MIXING TO IMPROVE CONDITIONS THERE. OUT ACROSS THE LOWLANDS WHERE CLEARING DID MANAGE TO TAKE PLACE...MVFR VALLEY MIST IS LIKELY...WITH IFR VALLEY FOG NEAR DAWN MOST LIKELY AT CRW AND CKB. THIS WILL BURN OFF AFTER SUNRISE...AND IT MAY HAVE DRIED OUT JUST ENOUGH TO NOT HAVE MORNING CU. HIGH PRESSURE MOVES E OF THE AREA WED...AND HIGH AND THEN MID CLOUD INCREASE AS AN ARCTIC FRONT APPROACHES FROM THE NW. THIS WILL START BRINGING LOWER CLOUDS AND SNOW SHOWERS INTO THE MIDDLE OHIO VALLEY 06Z THU. LIGHT N SFC FLOW BECOMES CALM BY DAWN AND THEN LIGHT AND VARIABLE WED...AND THEN LIGHT W TO SW AHEAD OF THE ARCTIC FRONT LATE WED AND WED EVENING. LIGHT AND VARIABLE FLOW ALOFT WILL BECOME LIGHT W WED AND THEN INCREASE TO MODERATE W WED NT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIO: IFR CONDITIONS IN THE MOUNTAINS MAY VARY...AS MAY FORMATION AND TIMING OF IFR FOG IN LOWLAND VALLEYS. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE WED 02/11/15 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12 CRW CONSISTENCY M M M M M M M H H H H H HTS CONSISTENCY M M M M H H H H H H H H BKW CONSISTENCY L M L L L L L L H H H H EKN CONSISTENCY L L L L L L L H H H H H PKB CONSISTENCY M M M M H H H H H H H H CKB CONSISTENCY M M M M M M M H H H H H AFTER 06Z THURSDAY... IFR IN THE MOUNTAINOUS COUNTIES IN SNOW SHOWERS ON THURSDAY...AND AT TIMES SATURDAY NIGHT...EACH IN THE WAKE OF ARCTIC FRONTS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...MZ NEAR TERM...TRM/MZ SHORT TERM...SL LONG TERM...ARJ AVIATION...TRM
AREA FORECAST DISCUSSION
NWS TULSA OK
1125 AM CST WED FEB 11 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. BAND OF STRATUS WITH MVFR CIGS WILL IMPACT THE NORTHEAST OK TAF SITES THIS AFTERNOON...AND MAY MOVE INTO NW AR AS WELL. THE BAND IS RATHER NARROW...SO EXPECT IMPROVEMENT FOR MOST AREAS LATER THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 1054 AM CST WED FEB 11 2015/ ..UPDATE... DISCUSSION... LEADING EDGE OF GUSTY N WINDS AND STRENGTHENING LOW-LEVEL COLD AIR ADVECTION HAS WORKED TO NEAR I-40...WITH RAGGED STRATUS DECK LAGGING BEHIND. WILL SEE MINIMAL WARMING THE REMAINDER OF THE DAY ACROSS NE OK...AND HAVE NUDGED UP HIGH TEMPS A BIT ACROSS FAR SE OK PER LATEST HRRR OUTPUT. SEEING A FEW RADAR ECHOES ACROSS SRN OK...SO A FEW SPRINKLES/LIGHT SHOWERS NOT OUT OF THE QUESTION THIS AFTERNOON. UPDATED PRODUCTS WILL BE OUT SHORTLY. && .PRELIMINARY POINT TEMPS/POPS... TUL 51 24 41 27 / 10 0 0 0 FSM 60 29 44 26 / 10 0 0 0 MLC 58 29 44 26 / 20 10 0 0 BVO 46 18 38 19 / 10 0 0 0 FYV 53 22 38 18 / 10 0 0 0 BYV 50 20 36 19 / 10 0 0 0 MKO 55 24 42 24 / 10 0 0 0 MIO 46 19 35 24 / 10 0 0 0 F10 54 26 43 25 / 10 0 0 0 HHW 63 33 49 26 / 20 10 0 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...18
AREA FORECAST DISCUSSION
NWS TULSA OK
1054 AM CST WED FEB 11 2015 ...UPDATE... .DISCUSSION... LEADING EDGE OF GUSTY N WINDS AND STRENGTHENING LOW-LEVEL COLD AIR ADVECTION HAS WORKED TO NEAR I-40...WITH RAGGED STRATUS DECK LAGGING BEHIND. WILL SEE MINIMAL WARMING THE REMAINDER OF THE DAY ACROSS NE OK...AND HAVE NUDGED UP HIGH TEMPS A BIT ACROSS FAR SE OK PER LATEST HRRR OUTPUT. SEEING A FEW RADAR ECHOES ACROSS SRN OK...SO A FEW SPRINKLES/LIGHT SHOWERS NOT OUT OF THE QUESTION THIS AFTERNOON. UPDATED PRODUCTS WILL BE OUT SHORTLY. && .PRELIMINARY POINT TEMPS/POPS... TUL 51 24 41 27 / 10 0 0 0 FSM 60 29 44 26 / 10 0 0 0 MLC 58 29 44 26 / 20 10 0 0 BVO 46 18 38 19 / 10 0 0 0 FYV 53 22 38 18 / 10 0 0 0 BYV 50 20 36 19 / 10 0 0 0 MKO 55 24 42 24 / 10 0 0 0 MIO 46 19 35 24 / 10 0 0 0 F10 54 26 43 25 / 10 0 0 0 HHW 63 33 49 26 / 20 10 0 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...18 LONG TERM....05
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
653 PM EST THU FEB 12 2015 .SYNOPSIS... AN ARCTIC FRONT WILL BRING SNOW SHOWERS AND A FEW SQUALLS TO CENTRAL PENNSYLVANIA TODAY FOLLOWED BY FRIGID TEMPERATURES TONIGHT INTO EARLY FRIDAY. ANOTHER ARCTIC BLAST IS EXPECTED THIS WEEKEND ALONG WITH ACCUMULATING SNOW FOR MOST OF THE AREA. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... THE AREA OF CONVECTIVE SNOW HAS ENDED AND THE MAIN ARCTIC COLD FRONT WILL PUSH NW TO SE THRU CENTRAL PA THROUGH THIS EVE. UPSLOPE FLOW WILL CONTINUE ACROSS THE LAURELS...HOWEVER LATEST HRRR SHOWS DECREASED SNOW FALL...WITH ONLY LIGHT ACCUMULATIONS POSSIBLE INTO FRIDAY MORNING. THE ADVECTION OF COLD ARCTIC AIR AND INCREASING WNW WINDS WITH FREQUENT GUSTS BETWEEN 25-40MPH ON THE BACKSIDE OF DEEPENING OFFSHORE LOW WILL CREATE FRIGID WIND CHILLS ACROSS THE AREA TONIGHT INTO EARLY FRIDAY. WIND CHILL WARNING FOR THE NORTHERN TIER REMAINS WITH EXTREMELY DANGEROUS READINGS IN THE -25 TO -35 BELOW ZERO RANGE. EXPANDED THE WIND CHILL ADVISORY TO INCLUDE THE REST OF THE COUNTIES BASED ON DROPPING MODEL TEMPS AND INCREASE GRADIENT WHICH SHOULD ALLOW WINDS TO REMAIN SUSTAINED INTO THE OVERNIGHT PERIOD WITH WIND CHILLS DROPPING TO 15 BELOW ZERO. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... HIGH PRESSURE RIDGE WILL BUILD INTO THE REGION FRIDAY...BRINGING SLOWLY DECREASING NW WINDS AND PARTLY TO MOSTLY SUNNY SKIES ACROSS THE CENTRAL AND SE ZONES. THE NW MTNS MAY HAVE A TOUGH TIME BREAKING UP THE SHALLOW STRATO CU AND SCT FLURRIES. FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER SEASON SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND -18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE SOUTHERN VALLEYS. ANOTHER TROUGH IS EXPECTED TO DROP DOWN THROUGH THE REGION EARLY SATURDAY MORNING. THIS SYSTEM HAS A DEEPER TROUGH WITH WINDS OUT OF THE SOUTHWEST. WITH A DECENT SHORTWAVE...AND STRONG LLJ THERE IS A GOOD CHANCE FOR ANOTHER ROUND OF SNOW SQUALLS SATURDAY INTO SATURDAY NIGHT. EVEN COLDER AIR LOOKS TO ADVECT INTO THE REGION SATURDAY NIGHT INTO SUNDAY...WITH THE WINDS PERSISTING INTO THE EVENING HOURS. GOOD CONFIDENCE IN LOW WIND CHILLS SATURDAY EVENING. && .LONG TERM /SUNDAY THROUGH THURSDAY/... LONG TERM WILL BE PUNCTUATED BY BRUTALLY COLD AIRMASS TO BEGIN THE PERIOD...WITH FRIGID WIND CHILLS AND MINI MAX RECORDS LIKELY ACROSS MUCH OF CENTRAL PA ON SUNDAY. STRONG CLIPPER DROPS ACROSS THE EASTERN GLAKS SAT NIGHT AND DEEPENS RAPIDLY OVER LONG ISLAND AND ALONG THE SOUTHERN NEW ENGLAND COAST...LIKELY THROWING ACCUMULATING SNOW OVER THE POCONO PLATEAU THROUGH SUNDAY MORNING. SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF MY CWA ON SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHTER ACCUMULATIONS IN FOR THAT LIKELIHOOD. THE DEEP CHILL WILL PERSIST ON MONDAY AS A SUCCESSION OF NORTHERN STREAM WAVES DROPS WELL SOUTH OF THE REGION THROUGH THE CENTRAL AND SOUTHERN PLAINS. SURFACE HIGH WILL PROPOGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING OFFSHORE ON TUESDAY. MODEL GUIDANCE AND EFS INDICATE PHASING OF NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND SOUTHEASTERN U.S. BY LATER TUE INTO WEDNESDAY...BRINGING THE CHANCE OF SNOW TO THE REGION. COLD NORTHWEST FLOW RESUMES FOR THE REMAINDER OF NEXT WEEK AS A MASSIVE RIDGE OF HIGH PRESSURE COVERS THE EASTERN HALF OF THE CONUS LATER WED-FRI. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... MAIN ISSUE OVERNIGHT AND FRIDAY MORNING WILL BE THE GUSTY WINDS AND EVEN BLOWING SNOW AT TIMES. MOST AREAS VFR...BUT MVFR AND IFR AT BFD AND JST INTO FRIDAY MORNING WITH SNOW SHOWERS. VFR FRIDAY AFT...WITH SOME MID LVL CLDS MOVING IN LATE. OUTLOOK... SAT...BCMG MVFR/IFR WITH -SN. FROPA FOLLOWED BY GUSTY WNW WINDS. SUN...MVFR/IFR WEST IN -SHSN. STRONG GUSTY WNW WINDS. MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR. TUE...MVFR/IFR WITH -SN. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR PAZ004>006-037- 042. WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR PAZ010>012- 017>019-024>028-033>036-041-045-046-049>053-056>059-063>066. WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ033. && $$ SYNOPSIS...STEINBUGL NEAR TERM...FITZGERALD/CERU SHORT TERM...FITZGERALD/CERU LONG TERM...DEVOIR/FITZGERALD AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
344 AM CST WED FEB 11 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST WED FEB 11 2015 A COLDER AND BREEZY DAY IS ON TAP FOR THE AREA TODAY. NORTHWESTERLY WINDS WILL AVERAGE 15 TO 30 MPH...WITH A FEW GUSTS APPROACHING 40 MPH...MAINLY IN SOUTHWEST MINNESOTA. CLOUD COVER A BIT TRICKY...BUT OVERALL THINKING IT STAYS MOSTLY CLOUDY. WE DO SEE ENOUGH DRYING THOUGH THAT THINK SOME PEAKS OF SUN ARE LIKELY. WIND CHILLS THIS MORNING WILL RANGE FROM 0 TO -10. HIGHS THIS AFTERNOON WILL REACH THE UPPER TEENS SOUTHWEST MINNESOTA TO THE UPPER 20S TO AROUND 30 ALONG THE MISSOURI RIVER. WILL SEE A SECONDARY SURGE OF COLD AIR DIVE SOUTH INTO THE REGION TONIGHT. THIS WILL HELP ENHANCE WINDS A BIT THIS EVENING AND WILL LIKELY APPROACH SUSTAINED ADVISORY CRITERIA OF 30 MPH...ESPECIALLY IN SOUTHWEST MINNESOTA. HOWEVER WILL BE PRETTY MARGINAL...AND THINKING THE HIGHEST GUSTS WILL GENERALLY STAY BELOW 45 MPH. SO WILL HOLD OFF ON ANY ADVISORY. TEMPERATURES WILL PLUMMET AGAIN TONIGHT...ALTHOUGH THE STRONG WINDS AND CLOUDS WILL PREVENT A RADIATIONAL DROP. AS THE SURFACE HIGH DROPS SOUTH...SKIES WILL CLEAR AND WINDS WILL WEAKEN BY MORNING...BUT WITHOUT SNOW COVER...STILL NOT THINKING TEMPERATURES REALLY TANK. THUS GOING WITH LOWS FROM 0 TO -5 IN THE NORTHEAST HALF OF THE AREA AND 0 TO +5 SOUTHWEST. WIND CHILLS WILL DROP INTO THE -10 TO -20 RANGE BY MIDNIGHT AND STAY THERE INTO THE MORNING. WILL BE AROUND WIND CHILL ADVISORY CRITERIA NORTHEAST OF A DESMET TO SIOUX FALLS TO SPENCER LINE...WITH VALUES BETWEEN -20 AND -25 POSSIBLE. GIVEN MARGINAL VALUES WILL NOT ISSUE ANYTHING AND LET DAY SHIFT REASSESS...EITHER WAY IT WILL BE A COLD MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 343 AM CST WED FEB 11 2015 THE FORECAST IN THE INTERMEDIATE AND LONGER TERM IS HIGHLIGHTED BY A SHARP NORTHWEST FLOW ALOFT WITH A BROAD LONG WAVE TROUGH DOMINATING EASTERN NORTH AMERICA. THIS PATTERN WILL CONTINUALLY GIVE OUR AREA SHORT WAVES MOVING DOWN FROM CANADA. THE PATTERN WILL BE WINDY... WITH PLENTY OF COLD AIR ADVECTION SURGES INTERRUPTED BY BRIEF WARM AIR ADVECTION PERIODS. ONCE SUCH BRIEF WARM ADVECTION SURGE OCCURS ON THURSDAY WHEN SURFACE HIGH PRESSURE MOVES OFF TO THE EAST. MANY OF THE DETERMINISTIC GLOBAL MODELS AS WELL AS HIRES SOLUTIONS CONTINUE TO SHOW A STRIPE OF SNOW DEVELOPING ON THE LEADING EDGE OF THE WARM FRONT. INCLUDED CHANCE POPS LATE THURSDAY AFTERNOON AND EVENING MAINLY EAST OF THE JAMES RIVER VALLEY WHERE MOISTURE PROFILES ARE FAIRLY SATURATED THROUGH A DEEP LAYER. THE ONLY THING LACKING IS STRONG MOISTURE BELOW ABOUT 800MB...OR THIS COULD BE A DECENT LIGHT SNOW EVENT. AS IT SITS NOW...SNOW AMOUNTS LOOK TO BE GENERALLY AROUND A HALF INCH OR LESS. BUT WOULD NOT BE SURPRISED AS WE GET CLOSER TO THE EVENT IF IT TURNS INTO A HIGH POP/LOW QPF EVENT FOR MANY AREAS...AT LEAST EAST OF I 29 IF THIS MODEL TREND CONTINUES. WITH THE AFOREMENTIONED WARM AIR ADVECTION...TEMPERATURES WILL NOT COOL OFF MUCH THURSDAY NIGHT IF ANY AT ALL...LEADING INTO A SEASONABLY MILD DAY ON FRIDAY AHEAD OF THE NEXT ARCTIC COLD FRONT. ON FRIDAY HIGHS SHOULD RANGE FROM THE 30S EAST...TO WIDESPREAD 40S IN OUR WESTERN ZONES. THEN THE BOTTOM FALLS OUT. BIG COLD FRONT MOVES SOUTHWARD FRIDAY NIGHT. ONCE AGAIN SIMILAR TO THE NEAR TERM...WOULD NOT BE SURPRISED IF WIND SPEEDS PUSHED WIND ADVISORY CRITERIA IN A 3 TO 6 HOUR PERIOD WITH THE STRONG COLD AIR ADVECTION PUSH. IN ADDITION...THE GFS SHOWS A BIT OF LIGHT SNOW POTENTIAL EAST OF THE JAMES RIVER FRIDAY NIGHT. HOWEVER THIS WAS NOT BACKED UP YET BY THE ECMWF OR GEM GLOBAL. THE ECMWF WAS THE FIRST MODEL TO PICK UP ON THE PROBABLE LIGHT SNOW EVENT FOR LATE THURSDAY AFTERNOON AND EVENING...LEADING THE OTHER TWO MODELS. THEREFORE WOULD NOT RULE OUT FLURRIES FRIDAY NIGHT BUT KEPT IT DRY FOR NOW DUE TO THE ECMWF AND GEM GLOBAL SOLUTIONS. SATURDAY WILL HARBOR A MINIMAL RISE IN TEMPERATURES OF ONLY ABOUT 5 DEGREES OFF OF MID MORNING LOWS. LIKELY STAYING IN THE SINGLE DIGITS ABOVE ZERO IN SOUTHWEST MN...TO MAYBE NEAR 20 IN GREGORY COUNTY. THEN SIMILAR TO THURSDAY...ANOTHER BRIEF SURGE OF WARM AIR ADVECTION SETS UP SATURDAY NIGHT EXCEPT THIS AIR MASS IS COLDER OVERALL. SLIGHT CHANCE TO CHANCE POPS ARE WARRANTED FOR MOST OF THE FORECAST AREA SATURDAY NIGHT AND/OR SUNDAY...WITH WHAT SHOULD BE AN INCH OR LESS OF SNOW POTENTIAL. AGAIN...IF THIS MODEL TREND HOLDS...POPS WILL BE GOING UP WITH FUTURE RUNS AS WE GET CLOSER TO THE EVENT. MONDAY CONTINUES TO BE AN INTERESTING DAY. THE ECMWF CONTINUES TO BE BULLISH WITH A DECENT SNOW EVENT AS A STRONG SHORT WAVE INTERACTS WITH STRONG LOW TO MID LEVEL CONVERGENCE. AT THE SURFACE...IT CONTINUES TO SHOW ANOTHER ARCTIC HIGH OOZING DOWN...COUPLED WITH LOW PRESSURE IN THE CENTRAL AND SOUTHERN PLAINS PROVIDING A GOOD SQUEEZE OF AIR IN OUR AREA WITH PLENTY OF ISENTROPIC LIFT. THE GEM AND GFS CONTINUE TO BE MUCH LESS BULLISH SO ONLY CHANCE POPS ARE WARRANTED. BUT SOMETHING TO WATCH FOR AS THE DAYS PROGRESS. ONE THING THE MODELS DO AGREE ON...IS MORE ARCTIC AIR POURING IN FOR NEXT TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1039 PM CST TUE FEB 10 2015 EXPECT MVFR CIGS TO LINGER THROUGH THE NIGHT IN THE COLD AIR ADVECTION REGIME BEHIND THE FRONT. TIMING OF THE STRATUS LIFTING OR CLEARING OUT IS UNCERTAIN...WITH THE NAM AND GFS HOLDING ONTO IT INTO WEDNESDAY WHILE THE HRRR LIFTS IT INTO VFR FROM WEST TO EAST EARLY IN THE TAF PERIOD. WILL GO WITH A MORE PESSIMISTIC SOLUTION WITH THE COLD AIR ADVECTION REGIME. SCATTERED FLURRIES WILL ALSO BE POSSIBLE OVERNIGHT. WINDS WILL BE BLUSTERY FROM THE NORTHWEST WITH GUSTS AS HIGH AS 35 KT INTO THE EARLY MORNING HOURS. WHILE WINDS DO DECREASE AROUND DAYBREAK...THEY WILL REMAIN BREEZY THROUGH THE DAY WEDNESDAY WITH GUSTS AROUND 20 TO 30 KT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...MJ AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1049 PM CST TUE FEB 10 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 255 PM CST TUE FEB 10 2015 PRECIPITATION OUT AHEAD OF A SURFACE TROUGH IS FINALLY COMING TO AN END OVER SOUTHWESTERN MINNESOTA THIS AFTERNOON. OTHERWISE...COLDER AIR WILL BEGIN FEEDING INTO THE REGION OVERNIGHT...AND WITH ENHANCED MIXING AND A TIGHTENING GRADIENT NORTHWESTERLY WINDS WILL PICK UP THROUGH THE EVENING AND CONTINUE THROUGH MOST OF THE DAY ON WEDNESDAY. A SHORTWAVE PRESENTLY OVER NORTH DAKOTA WILL DROP SOUTHWARD TONIGHT...AND MAY PROVIDE ENOUGH LIFT TO TRIGGER A FEW FLURRIES THROUGH OUR NORTH AND EAST IN A SATURATED DENDRITIC LAYER. WITH THE COLD AIR ADVECTION...IT WILL BE A MUCH COLDER NIGHT WITH LOWS IN THE TEENS TO AROUND 20. A SURFACE RIDGE WILL BUILD SOUTHWARD ACROSS THE REGION ON WEDNESDAY...AND AS MENTIONED PREVIOUSLY IT WILL BE WINDY. HIGHS WILL RUN FROM THE TEENS OVER EAST CENTRAL SD AND SOUTHWESTERN MN...TO THE UPPER 20S THROUGH THE MO RIVER CORRIDOR. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 255 PM CST TUE FEB 10 2015 COLD HIGH PRESSURE BUILDS INTO THE AREA ON WEDNESDAY NIGHT SO WENT AHEAD AND LOWERED LOWS JUST A TOUCH. WITHOUT A LOT OF SNOW COVER NOT GOING TO BE NEARLY AS COLD AS IT COULD BE. SINGLE DIGITS BELOW ZERO ALONG AND NORTH OF INTERSTATE 90 AND SINGLE DIGITS ABOVE ZERO SOUTH. THURSDAY WILL SEE HIGH PRESSURE SHIFT SOUTHEAST QUICKLY WITH RETURN FLOW AND WARMER AIR TRYING TO BUILD IN...MAINLY IN THE EVENING AND NIGHT TIME. SO THE HIGH TEMPERATURES WILL STILL BE PRETTY COLD...TEENS IN THE EAST AND LOWER 30S IN SOUTH CENTRAL SOUTH DAKOTA. WITH A FAVORABLE THERMAL PROFILE AND WEAK WAVE SLIDING SOUTH WILL ADD SOME SMALL POPS FOR LIGHT SNOW IN THE EASTERN THIRD OF THE CWA. RELATIVELY MILD THURSDAY NIGHT INTO FRIDAY WITH LOWS IN THE TEENS AND HIGHS FROM AROUND 30 IN SOUTHWEST MINNESOTA TO THE MID 40S IN SOUTH CENTRAL SOUTH DAKOTA. IN THE OUTER PERIODS (SATURDAY THROUGH TUESDAY)...WEST TO NORTHWEST FLOW ALOFT WILL OCCASIONALLY AMPLIFY TO A MORE NORTHERLY DIRECTION ALLOWING COLDER AIR TO FILTER IN. SATURDAY WILL BE ONE OF THESE TIMES WHEN SOME PRETTY DARN COLD AIR WILL DRIVE INTO THE REGION. WITH A DECENT GRADIENT IN THE MORNING THE ACTUAL TEMPERATURE WILL NOT BE TOO EXCESSIVELY COLD...MAINLY SINGLE DIGITS...BUT THE WIND CHILL VALUES WILL LIKELY FALL TO 15 BELOW TO 25 BELOW ZERO. NOT OUT OF THE QUESTION SATURDAY NIGHT INTO SUNDAY TO GET A LITTLE LIGHT SNOW AS RETURN FLOW ALOFT DEVELOPS BUT FOR NOW WILL KEEP POPS FAIRLY LOW. THE MODELS BECOME A LITTLE LESS AGREEABLE MONDAY INTO TUESDAY BUT STILL THE OVERALL MESSAGE WILL BE BELOW NORMAL TEMPERATURES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1039 PM CST TUE FEB 10 2015 EXPECT MVFR CIGS TO LINGER THROUGH THE NIGHT IN THE COLD AIR ADVECTION REGIME BEHIND THE FRONT. TIMING OF THE STRATUS LIFTING OR CLEARING OUT IS UNCERTAIN...WITH THE NAM AND GFS HOLDING ONTO IT INTO WEDNESDAY WHILE THE HRRR LIFTS IT INTO VFR FROM WEST TO EAST EARLY IN THE TAF PERIOD. WILL GO WITH A MORE PESSIMISTICSOLUTIONWITH THE COLD AIR ADVECTION REGIME. SCATTERED FLURRIES WILL ALSO BE POSSIBLE OVERNIGHT. WINDS WILL BE BLUSTERY FROM THE NORTHWEST WITH GUSTS AS HIGH AS 35 KT INTO THE EARLY MORNING HOURS. WHILE WINDS DO DECREASE AROUND DAYBREAK...THEY WILL REMAIN BREEZY THROUGH THE DAY WEDNESDAY WITH GUSTS AROUND 20 TO 30 KT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...08 AVIATION...
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1104 AM CST WED FEB 11 2015 .AVIATION... MVFR CIGS HAVE MOVED INTO ALL THREE TERMINALS LATE THIS MORNING AND THEY SHOULD REMAIN INTO THE EVENING BEFORE RETURNING TO VFR. WINDS WILL CONTINUE TO BE GUSTY INTO THIS EVENING AS WELL WITH SUSTAINED WINDS AROUND 25 KTS WITH GUST TO 35 KTS. THEY WILL LOWER TO LESS THAN 12 KTS AT ALL THREE TERMINALS AROUND 02Z. CDS HAS THE BEST CHANCE OF SEEING LIGHT RAIN TODAY...HOWEVER CHANCES ARE TOO LOW TO BE INCLUDED IN THE TAF AT THIS TIME. && .PREV DISCUSSION... /ISSUED 1049 AM CST WED FEB 11 2015/ UPDATE... UPDATED POP GRIDS TO SCALE BACK RAIN CHANCES THROUGH LATE AFTERNOON. WV IMAGERY SHOWS A SLOT OF DRY AIR PUSHING IN FROM THE WEST WHICH IS HELPING TO KEEP PRECIP TO THE NORTH AND WEST OF THE FA. RADAR RETURNS FROM KLBB SHOW LIGHT PRECIP OVER THE TX PANHANDLE REGION...HOWEVER THE KAMA RADAR SHOWS MUCH LESS COVERAGE OVERHEAD SHOWING THAT MOST OF WHAT IS FALLING IS IN THE FORM OF VIRGA THANKS TO DRY MID LEVELS. SO FAR THERE ARE NO AIRPORT OR MESONET OBS THAT SHOW ANY FALLING PRECIP ACROSS THE PANHANDLE. AS THE VIRGA WILL HELP WITH SOME TOP DOWN MOISTENING SLIGHT CHANCE POPS HAVE BEEN KEPT IN FOR OUR NORTHERN AND WESTERN COUNTIES...THOUGH IT IS UNKNOWN IF THAT WILL EVEN BE ENOUGH TO HELP RAIN REACH THE GROUND. PREV DISCUSSION... /ISSUED 404 AM CST WED FEB 11 2015/ SHORT TERM... NORTHERLY WIND SHIFT HAS PUSHED THROUGH ALREADY BUT STRONGER PRESSURE GRADIENT STILL AWAITS WITH MAIN COLD AIR ADVECTION LATER THIS MORNING INTO THE EARLY AFTERNOON. MOST RECENT RAP AND HRRR RUNS SEEM TO SUPPORT WIND SPEEDS NEAR OR JUST SHY OF WIND ADVISORY LEVELS. A WEAK UPPER LOW MEANWHILE EXPECTED TO PINCH OFF ACROSS THE SOUTHERN ROCKIES LATER TODAY WHILE DROPPING SOUTHWARD. BEST LIFT AND MOISTURE APPEAR TO REMAIN JUST TO OUR WEST...BUT PERHAPS ENOUGH LIFT WITH MEAGER MOISTURE LAYERS TO SUPPORT LOW CHANCES OF LIGHT RAIN OR SHOWERS MAINLY WESTERN AND CENTRAL ZONES AT LEAST THIS AFTERNOON AND EARLY EVENING. LATEST SOLUTIONS HAVE TRIMMED BETTER PRECIPITATION A BIT FURTHER WEST OF PREVIOUS FORECAST AND WE HAVE FOLLOWED THIS TREND AS WELL. DRYING AND SUBSIDENT AIRMASS SHOULD GRADUALLY TAKE BACK OVER OVERNIGHT. RECENT TEMPERATURE GUIDANCE REASONABLY SIMILAR TO PREVIOUS WITH ONLY MINOR CHANGES. RMCQUEEN LONG TERM... DRY NORTHWEST FLOW WILL SET UP THURSDAY INTO THE WEEKEND BETWEEN WEST COAST RIDGING EXTENDING INTO THE YUKON/NORTHWEST TERRITORIES AND LOCKED IN CYCLONIC FLOW ACROSS EASTERN NORTH AMERICA. SURFACE RIDGING WILL SLIDE EAST INTO THE MIDWEST THURSDAY AS LEE TROUGHING TAKES FORM IN THE FRONT RANGE BEFORE EJECTING INTO THE PLAINS FRIDAY BRINGING A NORTHERLY WIND SHIFT TO THE SOUTH PLAINS. ANY SEMBLANCE OF COOLER AIR WILL REMAIN BOTTLED UP SEVERAL HUNDRED MILES TO THE NORTHEAST...ALLOWING THE WARMING TREND TO CONTINUE INTO THE WEEKEND. AFTER TEMPERATURES TOPPING OUT NEAR NORMAL IN THE 50S THURSDAY...A STEADY RISE INTO THE 60S AND 70S WILL BE ON DECK FOR FRIDAY AND SATURDAY RESPECTIVELY. A BACKDOOR FRONT WILL PUSH THROUGH THE PLAINS SATURDAY AS YET ANOTHER LOBE OF ENERGY ROTATES AROUND A LOW ANCHORED IN VICINITY OF HUDSON BAY...ARRIVING SOMETIME EARLY SUNDAY AND LIKELY RESULTING IN A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT WITH HIGHS RANGING FROM THE UPPER 50S IN THE FAR SOUTHEAST PANHANDLE TO NEAR 70 IN THE SOUTHWEST SOUTH PLAINS. A SIGNIFICANT PATTERN CHANGE CONTINUES TO LOOM FOR EARLY NEXT WEEK WITH BACKING UPPER FLOW DOWNSTREAM OF AN UPPER LOW...ORIGINATING FROM A LOW OFF BAJA PHASING WITH THE RETROGRADE CUTOFF LOW RESPONSIBLE FOR TODAY/S FRONT...AND SHORTWAVE TROUGH MIGRATING SOUTHEASTWARD OUT OF WESTERN CANADA. MOISTURE ADVECTION LOOKS TO HAVE LONG ENOUGH OF A RESIDENCE TIME FOR PRECIPITATION TO BECOME A POSSIBILITY BY LATE MONDAY INTO TUESDAY AT THIS JUNCTURE. THIS LOOKS TO BE WHEN NWP SOLUTIONS BEST CONVERGE ON UPPER SUPPORT COMBINING WITH FRONTOGENETICAL FORCING FROM WHAT AT THIS POINT LOOKS TO BE A STOUT FRONT...SERVING AS A REMINDER THAT FEBRUARY IS INDEED WINTER IN THE NORTHERN HEMISPHERE. OVERALL TRENDS HAVE BEEN SHOWING THIS PATTERN DEVELOPING WITH EASTERN PACIFIC RIDGING BECOMING HIGHLY AMPLIFIED ENOUGH TO ALLOW FOR A SIGNIFICANT DUMP OF COLD AIR THROUGH THE CENTRAL CONUS. AS FAR AS PRECIPITATION TYPE...A MIX OF RAIN AND SNOW INITIALLY TRANSITIONING TO ALL SNOW SEEMS VALID GIVEN THIS EXPECTED PUNCH OF CANADIAN AIR LASTING INTO MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 43 26 55 30 / 20 10 0 0 TULIA 47 28 54 30 / 20 10 0 0 PLAINVIEW 49 28 54 30 / 10 10 0 0 LEVELLAND 50 30 54 31 / 10 20 0 0 LUBBOCK 51 30 54 31 / 10 10 0 0 DENVER CITY 50 31 54 30 / 20 30 0 0 BROWNFIELD 50 31 54 31 / 10 30 0 0 CHILDRESS 56 30 53 32 / 0 10 0 0 SPUR 53 31 53 31 / 0 10 0 0 ASPERMONT 57 33 52 33 / 0 10 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 51/93/51
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1049 AM CST WED FEB 11 2015 .UPDATE... UPDATED POP GRIDS TO SCALE BACK RAIN CHANCES THROUGH LATE AFTERNOON. WV IMAGERY SHOWS A SLOT OF DRY AIR PUSHING IN FROM THE WEST WHICH IS HELPING TO KEEP PRECIP TO THE NORTH AND WEST OF THE FA. RADAR RETURNS FROM KLBB SHOW LIGHT PRECIP OVER THE TX PANHANDLE REGION...HOWEVER THE KAMA RADAR SHOWS MUCH LESS COVERAGE OVERHEAD SHOWING THAT MOST OF WHAT IS FALLING IS IN THE FORM OF VIRGA THANKS TO DRY MID LEVELS. SO FAR THERE ARE NO AIRPORT OR MESONET OBS THAT SHOW ANY FALLING PRECIP ACROSS THE PANHANDLE. AS THE VIRGA WILL HELP WITH SOME TOP DOWN MOISTENING SLIGHT CHANCE POPS HAVE BEEN KEPT IN FOR OUR NORTHERN AND WESTERN COUNTIES...THOUGH IT IS UNKNOWN IF THAT WILL EVEN BE ENOUGH TO HELP RAIN REACH THE GROUND. && .PREV DISCUSSION... /ISSUED 545 AM CST WED FEB 11 2015/ AVIATION... WIND SPEEDS EXPECTED TO INCREASE BY MID TO LATE MORNING AS TIGHTER SURFACE PRESSURE PACKING MOVES IN. SOLUTIONS HAVE TRENDED A BIT LESS CERTAIN WITH AN MVFR CLOUD DECK FOR KCDS TODAY...BUT THIS STILL SEEMS LIKELY FOR KPVW AND KLBB THOUGH A BIT DELAYED. RAIN CHANCES TOO UNCERTAIN AT EITHER KPVW OR KLBB...BETTER TO THE WEST...FOR INCLUSION. CLOUDS SHOULD THIN TONIGHT. RMCQUEEN PREV DISCUSSION... /ISSUED 404 AM CST WED FEB 11 2015/ SHORT TERM... NORTHERLY WIND SHIFT HAS PUSHED THROUGH ALREADY BUT STRONGER PRESSURE GRADIENT STILL AWAITS WITH MAIN COLD AIR ADVECTION LATER THIS MORNING INTO THE EARLY AFTERNOON. MOST RECENT RAP AND HRRR RUNS SEEM TO SUPPORT WIND SPEEDS NEAR OR JUST SHY OF WIND ADVISORY LEVELS. A WEAK UPPER LOW MEANWHILE EXPECTED TO PINCH OFF ACROSS THE SOUTHERN ROCKIES LATER TODAY WHILE DROPPING SOUTHWARD. BEST LIFT AND MOISTURE APPEAR TO REMAIN JUST TO OUR WEST...BUT PERHAPS ENOUGH LIFT WITH MEAGER MOISTURE LAYERS TO SUPPORT LOW CHANCES OF LIGHT RAIN OR SHOWERS MAINLY WESTERN AND CENTRAL ZONES AT LEAST THIS AFTERNOON AND EARLY EVENING. LATEST SOLUTIONS HAVE TRIMMED BETTER PRECIPITATION A BIT FURTHER WEST OF PREVIOUS FORECAST AND WE HAVE FOLLOWED THIS TREND AS WELL. DRYING AND SUBSIDENT AIRMASS SHOULD GRADUALLY TAKE BACK OVER OVERNIGHT. RECENT TEMPERATURE GUIDANCE REASONABLY SIMILAR TO PREVIOUS WITH ONLY MINOR CHANGES. RMCQUEEN LONG TERM... DRY NORTHWEST FLOW WILL SET UP THURSDAY INTO THE WEEKEND BETWEEN WEST COAST RIDGING EXTENDING INTO THE YUKON/NORTHWEST TERRITORIES AND LOCKED IN CYCLONIC FLOW ACROSS EASTERN NORTH AMERICA. SURFACE RIDGING WILL SLIDE EAST INTO THE MIDWEST THURSDAY AS LEE TROUGHING TAKES FORM IN THE FRONT RANGE BEFORE EJECTING INTO THE PLAINS FRIDAY BRINGING A NORTHERLY WIND SHIFT TO THE SOUTH PLAINS. ANY SEMBLANCE OF COOLER AIR WILL REMAIN BOTTLED UP SEVERAL HUNDRED MILES TO THE NORTHEAST...ALLOWING THE WARMING TREND TO CONTINUE INTO THE WEEKEND. AFTER TEMPERATURES TOPPING OUT NEAR NORMAL IN THE 50S THURSDAY...A STEADY RISE INTO THE 60S AND 70S WILL BE ON DECK FOR FRIDAY AND SATURDAY RESPECTIVELY. A BACKDOOR FRONT WILL PUSH THROUGH THE PLAINS SATURDAY AS YET ANOTHER LOBE OF ENERGY ROTATES AROUND A LOW ANCHORED IN VICINITY OF HUDSON BAY...ARRIVING SOMETIME EARLY SUNDAY AND LIKELY RESULTING IN A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT WITH HIGHS RANGING FROM THE UPPER 50S IN THE FAR SOUTHEAST PANHANDLE TO NEAR 70 IN THE SOUTHWEST SOUTH PLAINS. A SIGNIFICANT PATTERN CHANGE CONTINUES TO LOOM FOR EARLY NEXT WEEK WITH BACKING UPPER FLOW DOWNSTREAM OF AN UPPER LOW...ORIGINATING FROM A LOW OFF BAJA PHASING WITH THE RETROGRADE CUTOFF LOW RESPONSIBLE FOR TODAY/S FRONT...AND SHORTWAVE TROUGH MIGRATING SOUTHEASTWARD OUT OF WESTERN CANADA. MOISTURE ADVECTION LOOKS TO HAVE LONG ENOUGH OF A RESIDENCE TIME FOR PRECIPITATION TO BECOME A POSSIBILITY BY LATE MONDAY INTO TUESDAY AT THIS JUNCTURE. THIS LOOKS TO BE WHEN NWP SOLUTIONS BEST CONVERGE ON UPPER SUPPORT COMBINING WITH FRONTOGENETICAL FORCING FROM WHAT AT THIS POINT LOOKS TO BE A STOUT FRONT...SERVING AS A REMINDER THAT FEBRUARY IS INDEED WINTER IN THE NORTHERN HEMISPHERE. OVERALL TRENDS HAVE BEEN SHOWING THIS PATTERN DEVELOPING WITH EASTERN PACIFIC RIDGING BECOMING HIGHLY AMPLIFIED ENOUGH TO ALLOW FOR A SIGNIFICANT DUMP OF COLD AIR THROUGH THE CENTRAL CONUS. AS FAR AS PRECIPITATION TYPE...A MIX OF RAIN AND SNOW INITIALLY TRANSITIONING TO ALL SNOW SEEMS VALID GIVEN THIS EXPECTED PUNCH OF CANADIAN AIR LASTING INTO MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 43 26 55 30 / 20 10 0 0 TULIA 47 28 54 30 / 20 10 0 0 PLAINVIEW 49 28 54 30 / 10 10 0 0 LEVELLAND 50 30 54 31 / 10 20 0 0 LUBBOCK 51 30 54 31 / 10 10 0 0 DENVER CITY 50 31 54 30 / 20 30 0 0 BROWNFIELD 50 31 54 31 / 10 30 0 0 CHILDRESS 56 30 53 32 / 0 10 0 0 SPUR 53 31 53 31 / 0 10 0 0 ASPERMONT 57 33 52 33 / 0 10 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 51/93
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
545 AM CST WED FEB 11 2015 .AVIATION... WIND SPEEDS EXPECTED TO INCREASE BY MID TO LATE MORNING AS TIGHTER SURFACE PRESSURE PACKING MOVES IN. SOLUTIONS HAVE TRENDED A BIT LESS CERTAIN WITH AN MVFR CLOUD DECK FOR KCDS TODAY...BUT THIS STILL SEEMS LIKELY FOR KPVW AND KLBB THOUGH A BIT DELAYED. RAIN CHANCES TOO UNCERTAIN AT EITHER KPVW OR KLBB...BETTER TO THE WEST...FOR INCLUSION. CLOUDS SHOULD THIN TONIGHT. RMCQUEEN && .PREV DISCUSSION... /ISSUED 404 AM CST WED FEB 11 2015/ SHORT TERM... NORTHERLY WIND SHIFT HAS PUSHED THROUGH ALREADY BUT STRONGER PRESSURE GRADIENT STILL AWAITS WITH MAIN COLD AIR ADVECTION LATER THIS MORNING INTO THE EARLY AFTERNOON. MOST RECENT RAP AND HRRR RUNS SEEM TO SUPPORT WIND SPEEDS NEAR OR JUST SHY OF WIND ADVISORY LEVELS. A WEAK UPPER LOW MEANWHILE EXPECTED TO PINCH OFF ACROSS THE SOUTHERN ROCKIES LATER TODAY WHILE DROPPING SOUTHWARD. BEST LIFT AND MOISTURE APPEAR TO REMAIN JUST TO OUR WEST...BUT PERHAPS ENOUGH LIFT WITH MEAGER MOISTURE LAYERS TO SUPPORT LOW CHANCES OF LIGHT RAIN OR SHOWERS MAINLY WESTERN AND CENTRAL ZONES AT LEAST THIS AFTERNOON AND EARLY EVENING. LATEST SOLUTIONS HAVE TRIMMED BETTER PRECIPITATION A BIT FURTHER WEST OF PREVIOUS FORECAST AND WE HAVE FOLLOWED THIS TREND AS WELL. DRYING AND SUBSIDENT AIRMASS SHOULD GRADUALLY TAKE BACK OVER OVERNIGHT. RECENT TEMPERATURE GUIDANCE REASONABLY SIMILAR TO PREVIOUS WITH ONLY MINOR CHANGES. RMCQUEEN LONG TERM... DRY NORTHWEST FLOW WILL SET UP THURSDAY INTO THE WEEKEND BETWEEN WEST COAST RIDGING EXTENDING INTO THE YUKON/NORTHWEST TERRITORIES AND LOCKED IN CYCLONIC FLOW ACROSS EASTERN NORTH AMERICA. SURFACE RIDGING WILL SLIDE EAST INTO THE MIDWEST THURSDAY AS LEE TROUGHING TAKES FORM IN THE FRONT RANGE BEFORE EJECTING INTO THE PLAINS FRIDAY BRINGING A NORTHERLY WIND SHIFT TO THE SOUTH PLAINS. ANY SEMBLANCE OF COOLER AIR WILL REMAIN BOTTLED UP SEVERAL HUNDRED MILES TO THE NORTHEAST...ALLOWING THE WARMING TREND TO CONTINUE INTO THE WEEKEND. AFTER TEMPERATURES TOPPING OUT NEAR NORMAL IN THE 50S THURSDAY...A STEADY RISE INTO THE 60S AND 70S WILL BE ON DECK FOR FRIDAY AND SATURDAY RESPECTIVELY. A BACKDOOR FRONT WILL PUSH THROUGH THE PLAINS SATURDAY AS YET ANOTHER LOBE OF ENERGY ROTATES AROUND A LOW ANCHORED IN VICINITY OF HUDSON BAY...ARRIVING SOMETIME EARLY SUNDAY AND LIKELY RESULTING IN A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT WITH HIGHS RANGING FROM THE UPPER 50S IN THE FAR SOUTHEAST PANHANDLE TO NEAR 70 IN THE SOUTHWEST SOUTH PLAINS. A SIGNIFICANT PATTERN CHANGE CONTINUES TO LOOM FOR EARLY NEXT WEEK WITH BACKING UPPER FLOW DOWNSTREAM OF AN UPPER LOW...ORIGINATING FROM A LOW OFF BAJA PHASING WITH THE RETROGRADE CUTOFF LOW RESPONSIBLE FOR TODAY/S FRONT...AND SHORTWAVE TROUGH MIGRATING SOUTHEASTWARD OUT OF WESTERN CANADA. MOISTURE ADVECTION LOOKS TO HAVE LONG ENOUGH OF A RESIDENCE TIME FOR PRECIPITATION TO BECOME A POSSIBILITY BY LATE MONDAY INTO TUESDAY AT THIS JUNCTURE. THIS LOOKS TO BE WHEN NWP SOLUTIONS BEST CONVERGE ON UPPER SUPPORT COMBINING WITH FRONTOGENETICAL FORCING FROM WHAT AT THIS POINT LOOKS TO BE A STOUT FRONT...SERVING AS A REMINDER THAT FEBRUARY IS INDEED WINTER IN THE NORTHERN HEMISPHERE. OVERALL TRENDS HAVE BEEN SHOWING THIS PATTERN DEVELOPING WITH EASTERN PACIFIC RIDGING BECOMING HIGHLY AMPLIFIED ENOUGH TO ALLOW FOR A SIGNIFICANT DUMP OF COLD AIR THROUGH THE CENTRAL CONUS. AS FAR AS PRECIPITATION TYPE...A MIX OF RAIN AND SNOW INITIALLY TRANSITIONING TO ALL SNOW SEEMS VALID GIVEN THIS EXPECTED PUNCH OF CANADIAN AIR LASTING INTO MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 43 26 55 30 / 40 10 0 0 TULIA 47 28 54 30 / 20 10 0 0 PLAINVIEW 49 28 54 30 / 20 10 0 0 LEVELLAND 50 30 54 31 / 20 20 0 0 LUBBOCK 51 30 54 31 / 20 10 0 0 DENVER CITY 50 31 54 30 / 20 30 0 0 BROWNFIELD 50 31 54 31 / 20 30 0 0 CHILDRESS 56 30 53 32 / 10 10 0 0 SPUR 53 31 53 31 / 10 10 0 0 ASPERMONT 57 33 52 33 / 10 10 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99/05
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
404 AM CST WED FEB 11 2015 .SHORT TERM... NORTHERLY WIND SHIFT HAS PUSHED THROUGH ALREADY BUT STRONGER PRESSURE GRADIENT STILL AWAITS WITH MAIN COLD AIR ADVECTION LATER THIS MORNING INTO THE EARLY AFTERNOON. MOST RECENT RAP AND HRRR RUNS SEEM TO SUPPORT WIND SPEEDS NEAR OR JUST SHY OF WIND ADVISORY LEVELS. A WEAK UPPER LOW MEANWHILE EXPECTED TO PINCH OFF ACROSS THE SOUTHERN ROCKIES LATER TODAY WHILE DROPPING SOUTHWARD. BEST LIFT AND MOISTURE APPEAR TO REMAIN JUST TO OUR WEST...BUT PERHAPS ENOUGH LIFT WITH MEAGER MOISTURE LAYERS TO SUPPORT LOW CHANCES OF LIGHT RAIN OR SHOWERS MAINLY WESTERN AND CENTRAL ZONES AT LEAST THIS AFTERNOON AND EARLY EVENING. LATEST SOLUTIONS HAVE TRIMMED BETTER PRECIPITATION A BIT FURTHER WEST OF PREVIOUS FORECAST AND WE HAVE FOLLOWED THIS TREND AS WELL. DRYING AND SUBSIDENT AIRMASS SHOULD GRADUALLY TAKE BACK OVER OVERNIGHT. RECENT TEMPERATURE GUIDANCE REASONABLY SIMILAR TO PREVIOUS WITH ONLY MINOR CHANGES. RMCQUEEN .LONG TERM... DRY NORTHWEST FLOW WILL SET UP THURSDAY INTO THE WEEKEND BETWEEN WEST COAST RIDGING EXTENDING INTO THE YUKON/NORTHWEST TERRITORIES AND LOCKED IN CYCLONIC FLOW ACROSS EASTERN NORTH AMERICA. SURFACE RIDGING WILL SLIDE EAST INTO THE MIDWEST THURSDAY AS LEE TROUGHING TAKES FORM IN THE FRONT RANGE BEFORE EJECTING INTO THE PLAINS FRIDAY BRINGING A NORTHERLY WIND SHIFT TO THE SOUTH PLAINS. ANY SEMBLANCE OF COOLER AIR WILL REMAIN BOTTLED UP SEVERAL HUNDRED MILES TO THE NORTHEAST...ALLOWING THE WARMING TREND TO CONTINUE INTO THE WEEKEND. AFTER TEMPERATURES TOPPING OUT NEAR NORMAL IN THE 50S THURSDAY...A STEADY RISE INTO THE 60S AND 70S WILL BE ON DECK FOR FRIDAY AND SATURDAY RESPECTIVELY. A BACKDOOR FRONT WILL PUSH THROUGH THE PLAINS SATURDAY AS YET ANOTHER LOBE OF ENERGY ROTATES AROUND A LOW ANCHORED IN VICINITY OF HUDSON BAY...ARRIVING SOMETIME EARLY SUNDAY AND LIKELY RESULTING IN A DECENT NORTHEAST TO SOUTHWEST TEMPERATURE GRADIENT WITH HIGHS RANGING FROM THE UPPER 50S IN THE FAR SOUTHEAST PANHANDLE TO NEAR 70 IN THE SOUTHWEST SOUTH PLAINS. A SIGNIFICANT PATTERN CHANGE CONTINUES TO LOOM FOR EARLY NEXT WEEK WITH BACKING UPPER FLOW DOWNSTREAM OF AN UPPER LOW...ORIGINATING FROM A LOW OFF BAJA PHASING WITH THE RETROGRADE CUTOFF LOW RESPONSIBLE FOR TODAY/S FRONT...AND SHORTWAVE TROUGH MIGRATING SOUTHEASTWARD OUT OF WESTERN CANADA. MOISTURE ADVECTION LOOKS TO HAVE LONG ENOUGH OF A RESIDENCE TIME FOR PRECIPITATION TO BECOME A POSSIBILITY BY LATE MONDAY INTO TUESDAY AT THIS JUNCTURE. THIS LOOKS TO BE WHEN NWP SOLUTIONS BEST CONVERGE ON UPPER SUPPORT COMBINING WITH FRONTOGENETICAL FORCING FROM WHAT AT THIS POINT LOOKS TO BE A STOUT FRONT...SERVING AS A REMINDER THAT FEBRUARY IS INDEED WINTER IN THE NORTHERN HEMISPHERE. OVERALL TRENDS HAVE BEEN SHOWING THIS PATTERN DEVELOPING WITH EASTERN PACIFIC RIDGING BECOMING HIGHLY AMPLIFIED ENOUGH TO ALLOW FOR A SIGNIFICANT DUMP OF COLD AIR THROUGH THE CENTRAL CONUS. AS FAR AS PRECIPITATION TYPE...A MIX OF RAIN AND SNOW INITIALLY TRANSITIONING TO ALL SNOW SEEMS VALID GIVEN THIS EXPECTED PUNCH OF CANADIAN AIR LASTING INTO MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 43 26 55 30 / 40 10 0 0 TULIA 47 28 54 30 / 20 10 0 0 PLAINVIEW 49 28 54 30 / 20 10 0 0 LEVELLAND 50 30 54 31 / 20 20 0 0 LUBBOCK 51 30 54 31 / 20 10 0 0 DENVER CITY 50 31 54 30 / 20 30 0 0 BROWNFIELD 50 31 54 31 / 20 30 0 0 CHILDRESS 56 30 53 32 / 10 10 0 0 SPUR 53 31 53 31 / 10 10 0 0 ASPERMONT 57 33 52 33 / 10 10 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/31
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
911 PM CST THU FEB 12 2015 .UPDATE... ISSUED AT 911 PM CST THU FEB 12 2015 THE MAIN FOCUS THIS EVENING IS ON THE SNOW CHANCES OVERNIGHT INTO FRIDAY. CURRENTLY...A BAND OF SNOW HAS DEVELOPED ALONG THE SOUTH DAKOTA/MINNESOTA BORDER AND IS TRAILING TO THE SOUTHEAST AND DIMINISHING AS IT GOES INTO WESTERN IOWA. THE NORTHERN EDGE OF IT IS FADING QUICK AS WELL...SO THE QUESTION IS WITH WHETHER THERE WILL BE ANY REDEVELOPMENT ALONG THIS BROAD LOW LEVEL WARM AIR ADVECTION DRIFTING EAST ACROSS THE REGION. RAP THERMAL PROFILES HAVE TRENDED TOWARD BEING MORE SATURATED WITH ENOUGH LIFT TO PRODUCE SOME LIGHT SNOW AS THE WAA COMES THROUGH. BASED ON THE 12.12/18Z NAM/GFS/ECMWF/GEM...THERE APPEARS TO BE TWO MAIN AREAS OF 850MB WAA WITH THE FIRST BEING ON THE BAND OF SNOW CURRENTLY OFF TO THE WEST AND ANOTHER DROPPING DOWN ACROSS NORTHERN MINNESOTA/WISCONSIN. IT APPEARS THAT OUR BEST SHOT AT SNOW COMES WITH THIS SECOND SHOT OF WAA WHICH COMES IN SLOWER THAN PREVIOUS TRENDS. SO...HAVE SLOWED DOWN THE SNOW CHANCES FOR OVERNIGHT INTO TOMORROW BUT KEPT AMOUNTS THE SAME AT LESS THAN AN INCH. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 251 PM CST THU FEB 12 2015 MAIN FCST CONCERNS THIS PERIOD...-SN CHANCES LATE TONIGHT/FRI MORNING...FLURRY/-SHSN CHANCES WITH ARCTIC FRONTAL PASSAGE FRI NIGHT...WINDS LATE FRI NIGHT...TEMPERATURES. 18Z DATA ANALYSIS HAD A 1036-1040MB CAN/ARCTIC HIGH FROM SOUTHWEST ONT TO EASTERN KS...DRIFTING SLOWLY SOUTHEAST ACROSS THE MID/UPPER MS VALLEY. GENERALLY CLEAR/SUNNY SKIES ACROSS MN/IA/WI UNDER THE HIGH...WITH ONLY SOME HIGH CLOUDS AHEAD OF THE NEXT NORTHWEST FLOW SHORTWAVE SPREADING OVER WESTERN MN. WINDS WERE LIGHT WITH WIND CHILLS ABATING. EVEN WITH THE SUNSHINE...MID-DAY TEMPS ACROSS MUCH OF MN/IA WI ONLY IN THE -10F TO +10F RANGE...SOME 10F-20F BELOW NORMAL. 12.12Z MODELS INITIALIZED WILL AND PRESENT VERY SIMILAR SOLUTIONS FOR TONIGHT THRU FRI NIGHT AS 2 NORTHWEST FLOW SYSTEMS IMPACT THE REGION. TREND IS A LITTLE FLATTER/WEAKER WITH A SHORTWAVE TO RIPPLE SOUTHEAST ACROSS THE REGION LATER TONIGHT/EARLY FRI...THEN A LITTLE STRONGER/SLOWER WITH THE SHORTWAVE TO DROP IN FRI NIGHT. GIVEN THE TIGHT CONSENSUS...SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE. FOR THE SHORT TERM...ALL MODELS SHOWING MID/HIGH LEVEL MOISTURE AT ABOVE 700MB TO INCREASE/THICKEN OVER THE REGION TONIGHT AS LOWER LEVEL WARM ADVECTION GRADUALLY SPREADS EAST ACROSS THE AREA. PREVIOUS FORECASTER TRENDED TONIGHTS LOWS LATE THIS EVENING THEN STEADY/SLOWLY RISING OVERNIGHT...WHICH LOOKS GOOD. TIGHT SIGNAL FOR THE 925-700MB MOISTURE IN THE WARM ADVECTION/LIFT AHEAD OF THE LOWER LEVEL WAVE TO SPREAD INTO THE WEST END OF THE FCST AREA AROUND 06Z...NOT REACHING THE EAST END OF THE FCST AREA UNTIL AROUND 12Z FRI. WEAKER/FLATTER TREND OF THE SHORTWAVE RESULTS IN LESS OF A LIFTING SIGNAL ACROSS THE AREA LATER TONIGHT/FRI. ALL MODELS HAVE TRENDED DRIER WITH THE QPF SINCE THE 11.12Z RUNS...BUT STILL MANAGE TO SQUEEZE OUT SOME VERY LIGHT QPF AS THE ROUND OF LOWER LEVEL THERMODYNAMIC FORCING PUSHES ACROSS THE FCST AREA. LIMITED -SN CHANCES TO WHEN THE 925-700MB MOISTURE MOVES INTO/ACROSS THE FCST AREA...AFTER MIDNIGHT TONIGHT THRU MAINLY FRI MORNING. MEASURABLE SNOW CHANCES IN THE 30-40 PERCENT 06-18Z FRI LOOK GOOD FOR NOW. APPEARS AROUND 1/2 INCH OF SNOW WOULD BE POSSIBLE IF THE STRONGER... MORE SATURATED OF THE MODELS WERE TO VERIFY. A WARMER DAY FRI WITH HIGHS NEAR NORMAL AS 925MB TEMPS WARM INTO THE -6C TO -9C IN THE WARM ADVECTION WESTERLY FLOW. WARMUP IS SHORT LIVED AS NEXT STRONG SHORTWAVE DROPS ACROSS LK SUPERIOR AND DRIVES A STRONG ARCTIC FRONT SOUTH ACROSS THE AREA FRI NIGHT. SFC-850MB LAYER GENERALLY REMAINS SATURATED FRI NIGHT...WITH SOME WEAK LIFT TO ACCOMPANY THE FRONT AS THE COLD ADVECTION PUTS THE SQUEEZE ON THE WATER HOLDING CAPACITY OF THE LOWER PORTION OF THE COLUMN. ADDED SCT FLURRY MENTION TO GRIDS FOR FRI NIGHT. 925MB TEMPS CRASH BACK INTO THE -16C TO -21C RANGE AFTER MIDNIGHT FRI NIGHT...WITH TEMPS A FEW DEGREES EITHER SIDE OF 0F BY 12Z SAT. THIS WITH GRADIENT WINDS AROUND 20KTS GUSTING 30-35KTS PRODUCING WIND CHILLS OF -10 TO -25 BY 12Z SAT. MAY YET NEED A WIND CHILL ADVISORY FOR NORTHERN PORTIONS OF THE FCST AREA LATE FRI NIGHT. FAVORED THE MODEL/ENSEMBLE CONSENSUS OF LOWS/HIGHS FOR TONIGHT THRU FRI NIGHT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 251 PM CST THU FEB 12 2015 FCST CONCERNS FOR SATURDAY THRU SUN NIGHT...COLD TEMPERATURES AS ARCTIC HIGH PRESSURE DRIFTS ACROSS THE UPPER MIDWEST...-SN CHANCES IN RETURNING WARM ADVECTION SUN NIGHT. 12.12Z MODELS IN GOOD AGREEMENT AS THE FRI NIGHT SHORTWAVE ROTATES QUICKLY SOUTHEAST/OUT OF THE REGION. TIGHTER CONSENSUS FOR SLOW HGT RISES LATER SAT/SAT NIGHT AS TROUGHING DEEPENS ALONG THE EAST COAST AND AHEAD OF ANOTHER SHORTWAVE PASSING NEAR LK WINNIPEG BY 12Z SUN. HGTS FALL AGAIN SUN/SUN NIGHT AS THIS ENERGY CARVES OUT MORE BROAD TROUGHING OVER THE NORTH-CENTRAL CONUS. SOME SHORTWAVE DETAIL DIFFERENCES BY SUN/SUN NIGHT BUT TREND IS FOR MORE TROUGHING/ SHORTWAVE ENERGY OVER THE NORTHERN PLAINS/UPPER MIDWEST FOR LATER SUN/SUN NIGHT. FCST CONFIDENCE IN THE SAT THRU SUN NIGHT PERIOD IS GOOD THIS CYCLE. 1040MB OR HIGHER ARCTIC HIGH TO BUILD ACROSS THE UPPER MIDWEST SAT THRU SUN. TIGHT PRESSURE GRADIENT AND COLD ADVECTION ON THE FRONT SIDE OF THE HIGH IS OVER THE AREA SAT. 925MB TEMPS PROGGED TO DROP INTO THE -20C TO -25C RANGE BY 00Z SUN AND REMAIN THERE SAT NIGHT. WITH NORTHWEST WINDS AROUND 20KTS GUSTING 25-35KTS MUCH OF SAT... TEMPS WILL STRUGGLE TO WARM MUCH IF AT ALL. IF FRI NIGHT COLD ADVECTION IS DELAYED A BIT...HIGHS SAT MAY BE IN THE 12-14Z RANGE THEN DROP A FEW DEGREES FOR THE REST OF THE DAY. WIND CHILLS MUCH OF SAT LOOKING TO BE IN THE -15 TO -25 RANGE AND APPEARS A WIND CHILL ADVISORY WILL BE NEEDED FOR PORTIONS OF THE FCST AREA AT LEAST SAT MORNING. SAT NIGHT SHAPING UP TO BE ONE OF THE COLDEST NIGHTS OF THE 2014-2015 WINTER WITH THE CENTER OF THE HIGH OVER WI/EASTERN IA AT 12Z SUN. LIGHT/CALM WINDS...MOSTLY CLEAR SKIES AND SNOW DEPTHS MOSTLY 3 TO 8 INCHES...MOST LOCATIONS LOOKING AT LOWS OF -10F TO -20F...PERHAPS AS LOW AS -30F IN THE SHELTERED LOW LAYING LOCATIONS. WINDS WILL BE QUITE LIGHT SAT NIGHT INTO SUN MORNING...BUT WITH TEMPS THAT COLD WILL LIKELY NEED A WIND CHILL ADVISORY FOR MOST IF NOT ALL OF THE FCST AREA FOR LATER SAT NIGHT/SUN MORNING. SLOW MODERATION STARTS SUN/SUN NIGHT AS THE CENTER OF THE HIGH DRIFTS EAST OF THE AREA AND LOW LEVEL WARM ADVECTION RETURNS. TEMPS SUN/SUN NIGHT STILL AROUND 20F BELOW NORMAL THOUGH. HIGHER LEVEL MOISTURE/ CLOUDS INCREASE THRU THE DAY SUNDAY WITH THE 925-700MB MOISTURE PROGGED SPREAD WEST TO EAST ACROSS THE FCST AREA LATER SUN AFTERNOON/SUN NIGHT. SMALL -SN CHANCE IN THE WEST END OF THE FCST AREA SUN AFTERNOON AND A SMALL CHANCE ACROSS MUCH OF THE FCST AREA SUN NIGHT REASONABLE FOR NOW. TRENDED TOWARD COLDER OF GUIDANCE LOWS SAT NIGHT...OTHERWISE STAYED NEAR THE MODEL/ENSEMBLE CONSENSUS FOR HIGHS/LOWS SAT/SUN/SUN NIGHT. FOR MONDAY THRU THURSDAY...DAYS 4 TO 7... MAIN FCST CONCERNS THIS PERIOD...SMALL -SN CHANCES CENTERED ON MON AND AGAIN THU...BELOW NORMAL TEMPERATURES THRU THE PERIOD. MEDIUM RANGE MODEL RUNS OF 12.00Z/12.12Z IN GOOD AGREEMENT FOR ANOTHER STRONGER SHORTWAVE TROUGH TO BE DROPPING INTO THE NORTHERN PLAINS MON...THEN MOVING INTO/ACROSS THE UPPER MIDWEST MON NIGHT THRU TUE NIGHT. DIFFERENCES BY 12Z WED ON HOW QUICKLY THE TROUGH AXIS WOULD MOVE EAST OF THE REGION...GFS FASTER...ECMWF SLOWER WITH EACH HOLDING CONSISTENCY TO ITS PREVIOUS RUNS. GENERAL AGREEMENT FOR THE TROUGHING TO SWING EAST OF THE AREA WED...WITH RISING HGTS WED NIGHT INTO THU AHEAD OF ANOTHER SHORTWAVE TROUGH PROGGED TO DROP SOUTH ACROSS MANITOBA. GIVEN THE GENERAL LARGER SCALE MODEL AGREEMENT NEXT WEEK...DAY 4-7 FCST CONFIDENCE IS AVERAGE THIS CYCLE. ROUND OF LOWER LEVEL WARM ADVECTION/ISENTROPIC LIFT TO SPREAD ACROSS THE AREA MON INTO MON NIGHT AS THE WEEKEND ARCTIC HIGH MOVES FURTHER EAST/SOUTH. SFC/LOWER LEVEL TROUGH WITH THE NEXT MID LEVEL SHORTWAVE ENERGY TO PUSH ACROSS THE REGION AS WELL MON/MON NIGHT. SMALL -SN CHANCES MON/MON NIGHT PER THE MODEL CONSENSUS REASONABLE FOR NOW UNTIL THE AVAILABLE MOISTURE DETAILS COME INTO BETTER FOCUS. PASSING SFC TROUGH USHERS ANOTHER CAN/ARCTIC HIGH INTO THE UPPER MIDWEST FOR LATER MON NIGHT INTO WED. AFTER A BIT OF A WARMUP MON...925MB TEMPS IN THE -8C TO -12C RANGE AT 00Z TUE...925MB TEMPS PROGGED BACK IN THE -19 TO -23C RANGE BY 12Z WED. ON WED..MORE PROGRESSIVE GFS SPREADS IN LOW LEVEL WARM ADVECTION WHILE ECMWF CONTINUES WITH COLD ADVECTION. OVERALL DIFFERENCE OF 925MB TEMPS ON WED ONLY 2C TO 4C...BUT NOT A LOT OF CONFIDENCE ON HIGHS GIVEN NORTHWEST VS. SOUTHWEST LOW LEVEL FLOW AND CLOUD DIFFERENCES BETWEEN GFS/ECMWF. MORE CONSISTENT SIGNAL FOR A STRONGER ROUND OF LOW LEVEL WARM ADVECTION/LIFT AHEAD OF THE NEXT TROUGH TO SPREAD ACROSS THE REGION THU. EVEN WITH THIS...NAEFS ENSEMBLE AVERAGE HAS LOW LEVEL TEMPS 1-2 STANDARD DEVIATIONS BELOW NORMAL ON THU. MODEL/ENSEMBLE CONSENSUS OF HIGHS/LOWS FOR MON-THU APPEARS WELL TRENDED FOR NOW...REMAINING SOME 5 TO 15 DEGREES BELOW NORMAL NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 548 PM CST THU FEB 12 2015 THE MAIN FOCUS IS ON THE SNOW CHANCES OVERNIGHT INTO FRIDAY MORNING AS A SYSTEM MOVES ACROSS SOUTHERN CANADA. A BAND OF LIGHT SNOW IS EXPECTED TO DEVELOP OVERNIGHT AND COME THROUGH RST/LSE CLOSER TO DAYBREAK TOMORROW MORNING AND ENDING BY EARLY AFTERNOON. THE MAIN QUESTION WITH THIS SNOW IS WITH HOW INTENSE IT WILL BE AND WHETHER ANY IFR CONDITIONS WILL OCCUR. THE TREND APPEARS TO BE FAVORING MORE OF AN MVFR/VFR SITUATION WITH VISIBILITY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...RRS LONG TERM....RRS AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
541 PM CST THU FEB 12 2015 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SYNOPSIS...ISSUED AT 239 PM CST THU FEB 12 2015 WATER VAPOR LOOP AND RUC ANALYSIS REVEALS AMPLIFIED PATTERN FEATURING WEST COAST RIDGE AND BROAD UPSTREAM TROF ACROSS MUCH OF NORTH AMERICA. MODELS INDICATE THIS PATTERN WILL STAY IN PLACE OVER MUCH OF NEXT WEEK ALLOWING FOR PERIODIC SURGES OF ARCTIC AIR INTO THE REGION RESULTING IN BLO NORMAL TEMPS. MODELS ADVERTISE ONLY PERIODIC LIGHT PCPN WITH A FEW CLIPPER SHORTWAVES TRAVERSING AREA. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 239 PM CST THU FEB 12 2015 MINS TEMP FCST TONIGHT COULD BE TRICKY AS WINDS WILL DIE OFF WITH SFC RDG MOVING ACROSS THE AREA. ALSO WAA MID-HIGH CLOUDS WILL BE SPREADING INTO THE AREA AHEAD OF SHORTWAVE AND ASSOC SFC LOW DIVING DOWN FM CENTRAL CANADA. THESE CLOUDS DEPENDING ON HOW THICK THEY ARE MAY TEMPER RADIATIONAL COOLING UNDER LIGHT WIND REGIME. GIVEN UNCERTAINTY WITH CLOUD THICKNESS DECIDED TO USED A BLEND OF COLDER BASE REG GEM/ECMWF TEMPS AND MOS GUIDE TEMPS WHICH WAS CLOSE TO PREV FCST AND IN MEDIUM RANGE OF TEMP GUIDANCE. BACKED OFF SLIGHTLY ON POPS FOR FRI AS MODELS INDICATE BEST MOISTURE AND ISENTROPIC ASCENT STAYING GENERALLY NORTH OF WI CLOSER TO TRACK OF SHORTWAVE AND ASSOC SFC LOW. HAVE POPS RANGING FROM HIGH CHC (AROUND 50 PCT) NORTH TO LOWER CHC 30-40 POPS FOR SOUTHERN PORTIONS OF CWA. WAA WL HELP TEMPS RECOVER TO AROUND 20F...BUT MAX TEMPS PROBABLY WON/T OCCUR UNTIL LATE IN THE DAY SO ADJUSTED DIURNAL CURVE ACCORDINGLY. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 233 PM CST THU FEB 12 2015 N-NW WINDS WILL BE ON THE INCREASE LATE FRIDAY NIGHT INTO SATURDAY THANKS TO THE INCREASING PRESSURE GRADIENT BETWEEN THE EXITING SFC LOW SHIFTING FROM JUST E OF LAKE SUPERIOR AT 00Z SATURDAY TO THE LOWER GREAT LAKES SATURDAY AFTERNOON...AND THE COLD ARCTIC HIGH SINKING ACROSS S CENTRAL CANADA AND INTO THE N PLAINS. WHILE THE COLDEST AIR WILL REMAIN N-NE OF WI...STILL EXPECT 850MB TEMPS TO BOTTOM OUT AROUND -27 TO -30C SATURDAY AFTERNOON. AS A RESULT...STEADY TO FALLING TEMPERATRUES WILL BE COMMON SATURDAY AS THIS COLDER AIR RUSHES IN. HIGHS SATURDAY MAY ONLY ONLY TOP OUT IN THE -3 TO 7F RANGE /COLDEST NE/. KEPT THE POTENTIAL FOR BLOWING SNOW WHERE POPS WERE OVER 14 PERCENT...AND WIND GUSTS WERE OVER 20KTS. THE BEST CHANCE OF SNOW WILL BE OVER THE N ANE E TIER COUNTIES AS LAKE EFFECT ON STRONG WINDS BLOW WELL INLAND AND INTO N WI. UNDER A CLEARING SKY SATURDAY NIGHT...AND WITH WINDS OF 5-10KTS OUT OF THE N-NNW...WIND CHILL READINGS OF 25 TO 30 BELOW ZERO WILL BE POSSIBLE. LOOK FOR LATER UPDATES AND FORECASTS ON THIS ARCTIC AIRMASS AND LOW WIND CHILLS. GENEARALLY FOLLOWED A MODEL BLEND FOR MUCH OF THIS PERIOD. NO SIGNIFICANT STORMS ANTICIPATED...BUT WITH COLD WEATHER CONTINUING. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 538 PM CST THU FEB 12 2015 EXPECT VFR CONDITIONS AT ALL TAF SITES TONIGHT...WITH ONLY MIDDLE AND HIGH CLOUDS ANTICIPATED. A CLIPPER LOW PRESSURE WILL TRACK NORTH OF THE REGION ON FRIDAY...AND BRING SOME LIGHT SNOW AND ASSOCIATED MVFR CONDITIONS DURING THE LATE MORNING AND AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS.......VOSS SHORT TERM.....VOSS LONG TERM......KF AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS RIVERTON WY
246 PM MST WED FEB 11 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 211 PM MST WED FEB 11 2015 TONIGHT-THURSDAY: LATEST WATER VAPOR LOOP WAS SHOWING THE UPPER LEVEL RIDGE CONTINUING TO DOMINATE THE REGION. HOWEVER...THERE IS SOME CIRRUS BEGINNING TO SPILL OVER THE RIDGE WHICH IS EXPECTED TO MOVE OVER THE AREA BEGINNING TONIGHT AND CONTINUING THROUGH TOMORROW. THIS MAY TEND TO RESTRICT TEMPERATURES A BIT TOMORROW...BUT IT SHOULD STILL BE A NICE DAY WITH FAIRLY LIGHT WIND SPEEDS. WE MAY STILL NEED TO CONTEND WITH SOME VALLEY FOG...BUT THE CIRRUS WILL TEND TO LIMIT THAT POTENTIAL. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 211 PM MST WED FEB 11 2015 THURSDAY NIGHT-FRIDAY NIGHT: NO SIGNIFICANT CHANGES ARE PLANNED THROUGH THIS PERIOD EITHER WITH MILD TEMPERATURES AND LIGHT WIND SPEEDS CONTINUING DUE TO THE INFLUENCE OF THE UPPER LEVEL RIDGE IN ROCKIES. WE MAY SEE ENOUGH MOISTURE AND UPSLOPE FLOW TO GENERATE A FEW RAIN OR SNOW SHOWERS IN YELLOWSTONE OR THE TETONS...BUT NOT EXPECTING ANYTHING MORE THAN A DUSTING. SATURDAY-WEDNESDAY: THINGS BECOME A LOT MORE ACTIVE AS WE APPROACH SUNDAY INTO SUNDAY NIGHT. THIS IS DUE TO A STRONG JET DIGGING SOUTH FROM BRITISH COLUMBIA. MEANWHILE...ANOTHER STRONG UPPER LEVEL JET IN THE NORTHERN PLAINS BEGINS TO DEPART THE REGION SUNDAY AFTERNOON INTO SUNDAY NIGHT. THIS DEPARTING JET WILL PUT US UNDER THE INFLUENCE OF THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET BEGINNING SUNDAY AFTERNOON. THERE WILL BE SOME WEAK CONDITIONAL INSTABILITY IN THE MOUNTAINS...BUT THERE COULD BE SOME GOOD INERTIAL INSTABILITY IN THE SOUTHERN HALF OF THE FORECAST AREA WHICH MAY PROMOTE SOME WIDELY SCATTERED RAIN SHOWERS SUNDAY AFTERNOON. THE MAIN SHOW IS PROGGED TO SETUP SUNDAY NIGHT INTO MONDAY MORNING AS THE COLD FRONT BEGINS TO MOVE THROUGH THE AREA. IT APPEARS TO BE ENOUGH LIFT TO PRODUCE SOME WIDESPREAD SNOW ESPECIALLY IF WE CAN GET INFLUENCED BY A COUPLED JET SCENARIO. OTHERWISE...MUCH COLDER AIR WILL BEGIN TO SETTLE INTO THE REGION ON MONDAY NIGHT INTO TUESDAY AS THE ARCTIC HIGH MOVES IN. IN FACT...HIGHS MAY STRUGGLE TO GET OUT OF THE TEENS ON TUESDAY WITH OVERNIGHT LOWS DROPPING BELOW ZERO IN SOME OF THE VALLEYS TUESDAY NIGHT INTO WEDNESDAY MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1037 AM MST WED FEB 11 2015 PATCHY DENSE FOG IN THE VALLEY CONTINUES TO PLAGUE THE KCOD TAF SITE THIS MORNING. THIS IS DUE TO GOOD UPVALLEY FLOW WHICH IS CONTRIBUTING TO THE FOG. WE ARE NOT REAL CONFIDENT WHEN THIS FOG WILL ERODE...BUT WE DID NOTICE THE VISIBILITY WAS TRYING TO IMPROVE DURING THE LAST HOUR. HOWEVER...THE HRRR WAS CONTINUING TO SHOW THE UPVALLEY FLOW CONTINUING DURING THE NEXT COUPLE OF HOURS. AS A RESULT...WE WENT AHEAD AND KEPT THE VISIBILITY LOW THROUGH ABOUT 20Z OR SO. MEANWHILE...THE KJAC/KRKS TAF SITES ARE SHOWING MVFR CEILINGS BUT THESE CEILINGS IMPROVE PRETTY QUICKLY. THE REST OF THE TAF SITES VFR CONDITIONS SHOULD PREVAIL WITH MAINLY LIGHT AND VARIABLE WINDS. && .FIRE WEATHER... ISSUED AT 211 PM MST WED FEB 11 2015 A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA AND BRING MAINLY DRY AND MILD WEATHER THROUGH SATURDAY. TEMPERATURES WILL BE WELL ABOVE NORMAL FOR THURSDAY AND FRIDAY. A GUSTY BREEZE WILL BLOW AT TIMES ACROSS THE SOUTHWESTERN WIND CORRIDOR AND EAST OF THE ABSAROKAS. RELATIVE HUMIDITY WILL LOWER SUBSTANTIALLY FOR THURSDAY BUT WILL REMAIN ABOVE RED FLAG CRITERIA. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...COX LONG TERM...COX FIRE WEATHER...COX
AREA FORECAST DISCUSSION
NWS RIVERTON WY
1050 AM MST WED FEB 11 2015 .SHORT TERM...WEDNESDAY THROUGH FRIDAY NIGHT ALL IN ALL FAIRLY QUIET IN THE SHORT TERM AS SPRING IN FEBRUARY CONTINUES. A WEAK COLD FRONT SHOULD BE SOUTH OF THE STATE BY MORNING. A FEW CONVECTIVE SHOWERS DEVELOPED WITH THE UNSTABLE NORTHWESTERLY FLOW AND THESE ARE ENDING OR MOVING AWAY. BY MORNING...OTHER THAN MAYBE A LEFTOVER SHOWER IN THE BIG HORN RANGE...MOST AREAS SHOULD BE DRY BY DAYBREAK. THERE COULD ALSO BE A BIT OF FOG AROUND EARLY WHERE THE SHOWERS FELL. OTHERWISE...NO CONCERNS AS RIDGING MOVES ACROSS THE STATE AND BRINGS INCREASING AMOUNTS OF SUNSHINE. TEMPERATURES WILL BE A FEW DEGREES COLDER...BUT STILL WARM FOR MID FEBRUARY. MAINLY QUIET WEATHER WILL CONTINUE THROUGH THE END OF THE WORKWEEK AS WELL. 700 MILLIBAR WINDS INCREASE FOR THURSDAY SO SOME OF THE NORMALLY WINDIER SPOTS LIKE THE SOUTHWEST WIND CORRIDOR AND EAST OF THE ABSAROKAS COULD SEE SOME GUSTY WINDS THURSDAY OR FRIDAY. OTHERWISE...NO REAL CONCERNS. A WEAK SHORTWAVE MOVES ACROSS THURSDAY BUT WITH NO MOISTURE TO WORK WITH WE EXPECT ONLY SOME CLOUDS. FRIDAY ALSO LOOKS MAINLY DRY. TEMPERATURES WILL CONTINUE TO BE WELL ABOVE AVERAGE WITH HIGHS IN THE 50S COMMONPLACE ACROSS THE LOWER ELEVATIONS. HOWEVER...DO NOT GET USED TO IT. AS CLASSIC ROCKER DAVID BOWIE SAID...THERE WILL BE CH-CH-CH CHANGES TO THE WEATHER PATTERN LATER THIS WEEKEND. MORE ON THAT IN THE LONG TERM DISCUSSION. .LONG TERM...SATURDAY THROUGH WEDNESDAY ...MUCH COLDER TEMPERATURES AND SNOW ON THE WAY SUNDAY NIGHT INTO TUESDAY... SYNOPSIS...THE AREA WILL HAVE ONE MORE DAY OF UNSEASONABLY MILD AND DRY WEATHER ON SATURDAY. A FAST-MOVING DISTURBANCE ACROSS THE NORTHERN ROCKIES WILL BRING SOME SNOW SHOWERS ACROSS THE NORTHERN MOUNTAINS SATURDAY NIGHT. CHANCES OF SNOW WILL INCREASE ACROSS THE AREA SUNDAY AND SUNDAY NIGHT AS A MORE POTENT SYSTEM DIGS SOUTH INTO THE GREAT BASIN. THIS SYSTEM WILL PULL A CANADIAN COLD FRONT SOUTH ACROSS WYOMING SUNDAY NIGHT ACCOMPANIED BY GUSTY NORTH WIND AND SNOW. SNOW IS EXPECTED TO TAPER OFF FROM THE NORTH TUESDAY AS A DEEPER ARCTIC AIRMASS SETTLES IN. DRY AND COLD CONDITIONS ARE EXPECTED WEDNESDAY. DISCUSSION...MEDIUM-RANGE GLOBAL MODELS ALONG WITH ECMWF AND GFS ENSEMBLE MEANS HAVE ALL LATCHED ON TO A ARCTIC INTRUSION EARLY NEXT WEEK WITH LESS AGREEMENT AT MID-WEEK ON HOW FAST TO PUSH THE ARCTIC AIRMASS OUT OF THE AREA. FAST-MOVING SHORTWAVE CRASHES INTO UPPER RIDGE OVER THE INTERMOUNTAIN WEST ON SATURDAY. MOST PRECIPITATION EXPECTED TO STAY NORTH OF WYOMING WITH THIS SYSTEM...BUT IT IS EXPECTED TO KICK UP THE WINDS THROUGH THE DAY SATURDAY INTO SATURDAY NIGHT. A SHARP UPPER RIDGE IS EXPECTED TO BUILD OFF THE WEST COAST ON SUNDAY FORMING A HIGH AMPLITUDE RIDGE REACHING DEEP INTO THE ARCTIC ON MONDAY. POLAR JET STREAM IS EXPECTED TO EXTEND FROM NORTHERN ALASKA/YUKON WEST OF THE DIVIDE INTO THE GREAT BASIN ON MONDAY...CARVING OUT LONGWAVE TROUGH ACROSS THE ROCKIES. THE BEST SETUP FOR HEAVIER SNOW WILL BE SUNDAY NIGHT INTO MONDAY WITH POSSIBILITY OF BAROCLINIC LEAF FORMING OVER SURFACE FRONT. H5 -30 ISOTHERM IS EXPECTED TO PUSH SOUTH ACROSS THE AREA MONDAY AFTERNOON...OR TOO COLD TO HOLD MUCH MOISTURE WITH SNOW BECOMING LIGHT. 1045 MB ARCTIC HIGH PRESSURE WILL BUILD IN TO THE AREA ON TUESDAY ALONG WITH H7 TEMPS -20C OR COLDER...SO HIGHS ON TUESDAY WILL LIKELY STRUGGLE TO GET OUT OF THE SINGLE DIGITS. FORECAST HAS BEEN TRENDED IN THIS DIRECTION FROM PREVIOUS MODEL RUNS THAT KEPT THE ARCTIC AIR MOSTLY TO THE EAST. WOULD LIKE TO SEE SOME CONTINUITY IN NEXT SET OR TWO OF MODEL RUNS TO GO FULL ARCTIC BLAST FOR TUESDAY. RIGHT NOW FORECAST HAS MOST HIGHS IN THE TEENS EAST OF THE DIVIDE ON TUESDAY. GFS EXPANDS RIDGE OFF THE WEST COAST EAST INTO THE ROCKIES ON WEDNESDAY WHILE ECMWF MAINTAINS SHARPER RIDGE ALONG THE WEST COAST AND KEEPS COLD ARCTIC AIRMASS OVER WYOMING. FORECAST ALLOWS FOR SOME MODERATION OF TEMPERATURES ON WEDNESDAY...OR A COMPROMISE BETWEEN THE TWO EXTREMES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1037 AM MST WED FEB 11 2015 PATCHY DENSE FOG IN THE VALLEY CONTINUES TO PLAGUE THE KCOD TAF SITE THIS MORNING. THIS IS DUE TO GOOD UPVALLEY FLOW WHICH IS CONTRIBUTING TO THE FOG. WE ARE NOT REAL CONFIDENT WHEN THIS FOG WILL ERODE...BUT WE DID NOTICE THE VISIBILITY WAS TRYING TO IMPROVE DURING THE LAST HOUR. HOWEVER...THE HRRR WAS CONTINUING TO SHOW THE UPVALLEY FLOW CONTINUING DURING THE NEXT COUPLE OF HOURS. AS A RESULT...WE WENT AHEAD AND KEPT THE VISIBILITY LOW THROUGH ABOUT 20Z OR SO. MEANWHILE...THE KJAC/KRKS TAF SITES ARE SHOWING MVFR CEILINGS BUT THESE CEILINGS IMPROVE PRETTY QUICKLY. THE REST OF THE TAF SITES VFR CONDITIONS SHOULD PREVAIL WITH MAINLY LIGHT AND VARIABLE WINDS. && .FIRE WEATHER... A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA AND BRING MAINLY DRY AND MILD WEATHER THROUGH FRIDAY. TEMPERATURES WILL BE A FEW DEGREES COOLER TODAY BEHIND A WEAK COLD FRONT...BUT STILL QUITE MILD FOR FEBRUARY. TEMPERATURES WILL BE WELL ABOVE NORMAL FOR THURSDAY AND FRIDAY. A GUSTY BREEZE WILL BLOW AT TIMES ACROSS THE SOUTHWESTERN WIND CORRIDOR AND EAST OF THE ABSAROKAS. RELATIVE HUMIDITY WILL LOWER SUBSTANTIALLY FOR THURSDAY BUT REMAIN ABOVE && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HATTINGS LONG TERM...AEM AVIATION...COX FIRE WEATHER...HATTINGS
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
952 PM PST Thu Feb 12 2015 .Synopsis... Benign weather and mild temperatures will continue into at least the middle of next week under high pressure. Patchy fog is possible across southern Sacramento and northern San Joaquin valleys each morning. && .Discussion... Afternoon high temperatures were unseasonably warm today reaching the low to mid 70`s in the valleys...which is 10 to 15 degrees above normal. As a result many places were at or near records with Sacramento exec tying the record of 73 degrees and Stockton breaking the record of 71 after reaching 72 degrees. Forecast challenge overnight will revolve around fog formation. HRRR and WRF both showing fog formation Sacramento south...although LAMP and mos guidance is more bearish on development keeping vis greater than 3 miles. The situation is further complicated by high cloudiness spreading overhead...which will reduce fog threat. Feel the best chances will be Stockton/Modesto San Joaquin valley areas with likelihood diminishing northward. .Previous Discussion... Benign weather through the weekend as pesky ridge keeps choke-hold on Norcal. Above normal temperatures will continue with daytime highs in the 60s and 70s, some 5 to 15 degrees above normal. Patches of high clouds will be present from time to time through the period as a few weak systems ride the top of the ridge...far to the north of the local area. Fog development has been limited to valley locations south of Sacramento the past few mornings...mainly in northern San Joaquin valley. Suspect this will be the case again for next few overnights/mornings altho it may creep toward Sac Metro. Given time of year and full sunshine, any fog will quickly burn off after sunrise with limited impacts. CEO && .Extended Discussion (Monday through Thursday) Dry and warm weather is expected through the extended period period with morning fog in portions of the southern Sacramento and northern San Joaquin valleys. Daytime highs will be above normal but will be gradually trending down from peak warmth from the weekend. Strong ridging dominates at least through the first half of the week, but may gradually give way as a shortwave trough attempts to go through/over late in the week. The GFS, ECMWF and the GEM all have variations on the method and the timing of this. The ECMWF brings it rather quickly through and down south along the Sierra Thursday as something of an inside slider. Most precipitation would likely stay to the north and east of the forecast area. The GFS closes off the shortwave into a low and gradually brings it over northern California Friday through Sunday. The GFS is certainly the wetter solution of the two, but it has changed quite a bit from previous runs, so confidence is low at this point. EK && .Aviation... VFR conditions with SCT-BKN cirrus over interior Norcal. Brief periods of local MVFR/IFR/LIFR wx conditions due to Stratus/Fog expected to redevelop from KMYV southward to KMOD 10z-18z Fri. Light winds across the region. Stratus/fog possible in some of the higher mountain valleys during the morning hrs next couple of mornings. && .STO Watches/Warnings/Advisories... None. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1132 PM CST THU FEB 12 2015 .UPDATE... 800 PM CST EVENING UPDATE... WILL LET WINTER STORM WARNING FOR PORTER COUNTY EXPIRE ON SCHEDULE THIS EVENING...AS LAKE EFFECT SNOW HAS WEAKENED AND SHIFTED EAST OF THE AREA. OTHER MINOR CHANGES TO FORECAST WAS TO INCREASE CLOUD COVER A BIT AND SLOW TEMPERATURE DROP OFF THIS EVENING WITH CIRRUS AND PATCHY MID CLOUD OVER MUCH OF THE CWA. HEIGHT RISES AND STRONG SUBSIDENCE IN THE WAKE OF THIS MORNING/S STRONG SHORT WAVE DISTURBANCE HAS RESULTED IN SURFACE HIGH PRESSURE SPREADING ACROSS THE MID-MISSISSIPPI VALLEY AND INTO WEST CENTRAL IL THROUGH EARLY THIS EVENING. WEAKENING/BACKING OF LOW LEVEL WIND FIELD AND ASSOCIATED WEAKENING CONVERGENCE OVER LAKE MICHIGAN COMBINED WITH LOWERING SUBSIDENCE INVERSION HAS ALLOWED LAKE EFFECT SNOW TO WEAKEN FROM STRONG SINGLE-BAND EARLIER THIS AFTERNOON TO MUCH LESS INTENSE PARALLEL BAND SHOWERS FOCUSED LARGELY INTO MI/IN EAST OF PORTER COUNTY AT 755 PM. OTHER THAN A FEW LINGERING FLURRIES SNOW HAS ENDED...AND THE WINTER STORM WARNING WILL EXPIRE AT 8 PM CST AS PLANNED. OTHERWISE...CONSIDERABLE MID/HIGH CLOUD COVER...THOUGH THIN IN SPOTS...HAS RESULTED IN TEMPS FALLING OFF MORE SLOWLY THAN FORECAST. HAVE INCREASED CLOUD COVER AND SLOWED THE TEMPERATURE ROLL OFF THROUGH THIS EVENING...THOUGH MINS FROM GOING FORECAST STILL LOOK REASONABLE WITH LIGHT/VARIABLE WINDS IN SURFACE RIDGE AND ANY CLEARING AFTER MIDNIGHT. OTHER THAN AFOREMENTIONED TWEAKS TO HOURLY FORECAST GRIDS...NO SIG CHANGES TO GOING FORECAST FOR TONIGHT. RATZER && .SHORT TERM... 323 PM CST TONIGHT THROUGH SUNDAY... MULTIPLE WINTER CONCERNS OVER THE NEXT FEW DAYS...INCLUDING IN ORDER OF SIGNIFICANCE: ANOTHER SIGNIFICANT LAKE EFFECT EVENT APPEARING LIKELY LATE SATURDAY INTO SUNDAY MORNING...BITTERLY COLD AND WINDY ON VALENTINES DAY AND NIGHT...SNOW SHOWERS WITH AN ARCTIC FRONT FRIDAY NIGHT...AND POSSIBLE LIGHT SNOW ON FRIDAY. TONIGHT...WILL LIKELY BE ABLE TO EXPIRE WSW IN PORTER CO. FOR LAKE EFFECT AS PLANNED OR POSSIBLY EARLIER AS SNOW SHOWERS CONTINUE TO WEAKEN IN INTENSITY. ARCTIC HIGH WILL BE OVERHEAD BUT THEN SHIFT EAST. INCREASING CLOUDS WILL PREVENT A MUCH COLDER NIGHT...THOUGH LOW MINUS SINGLE DIGITS APPEAR A GOOD BET IN TYPICAL COLDER SPOTS...WITH POSITIVE SINGLE DIGITS FOR THE REST OF THE AREA. ON FRIDAY...WARM FRONT TRAILING FROM CLIPPER TRACKING NEAR LAKE SUPERIOR WILL APPROACH AREA...WITH BROAD ASCENT. HAVE CONCERN WITH SOME GUIDANCE...NAMELY ECMWF...KEEPING THINGS DRY...BUT NAM/GFS/GEM FORECAST SOUNDINGS INDICATE ENOUGH SATURATION AND WEAK ASCENT THROUGH DGZ FROM THE LATE MORNING INTO EARLY AFTERNOON MAINLY NORTH OF I-80. SHOULD SEE AN AREA OF LIGHT SNOW LIFTING NORTHEAST...WHICH COULD PUT DOWN A DUSTING IN SPOTS. CONTINUED WARM ADVECTION THROUGH LATE DAY SHOULD ENABLE TEMPS TO RECOVER INTO 20S AREA WIDE. FRIDAY NIGHT...VERY IMPRESSIVE ARCTIC FRONT WILL APPROACH AREA LATE IN THE NIGHT. 850 MB TEMPS OUT AHEAD OF IT ACTUALLY WARM TO LOWER MINUS SINGLE DIGITS CELSIUS...SO -25 TO -30C AIR BEHIND FRONT WILL SHARPEN THERMAL GRADIENT AND QUICKLY STEEPEN LAPSE RATES ALONG AND BEHIND FRONT. ASCENT WILL BE ASSISTED BY VERY POWERFUL MIDLEVEL SHORT WAVE DIVING SOUTHEASTWARD AND NOSE OF 140 KT UPPER JET. THUS EXPECT...SNOW SHOWERS TO BREAK OUT MAINLY AFTER MIDNIGHT AND SPREAD SOUTH. COULD SEE A HALF INCH TO EVEN AS MUCH AS AN INCH IN SPOTS BY DAYBREAK SATURDAY...ESPECIALLY ALONG/SOUTH OF I-88. BUMPED POPS TO MID/HIGH CHANCE IN THIS PERIOD. LOW TEMPERATURES ARE LIKELY TO BE SATURDAY`S HIGH TEMPS WITH MUCH OF THE NIGHT REMAINING NEARLY STEADY FROM FRIDAY HIGHS UNTIL FROPA. SATURDAY AND SUNDAY NOT INCLUDING LAKE EFFECT....THE ARCTIC DAM WILL BREAK ON SATURDAY ...WITH NO MODERATION SHOWN IN GUIDANCE OF -25 TO -27C 850 MB THERMAL TROUGH ARRIVING BY MID DAY ON VALENTINES DAY. TEMPERATURES WILL PLUMMET AS STRONG COLD ADVECTION RAMPS UP. COULD SEE SOME FLURRIES AND SNOW SHOWERS CONTINUE IN THE MORNING AS LIFT WILL STILL BE PROVIDED FROM POWERFUL UPPER VORT OVER AREA...THOUGH ARCTIC AIR MASS WILL BECOME INCREASINGLY DRY. EXTREMELY STRONG PRESSURE GRADIENT BETWEEN 1045 MB+ ARCTIC HIGH OVER NORTHERN PLAINS AND CLIPPER DEEPENING TO SUB 1000 MB OVER EASTERN LAKES WILL RESULT IN NNW WINDS GUSTING TO 35 TO 45 MPH AND POSSIBLY STRONGER ON INDIANA SHORE...WHERE A WIND HEADLINE MAY BE NEEDED PRIOR TO LAKE EFFECT ISSUES. WIND CHILL VALUES WILL FALL TO 10 TO 20 BELOW BY LATE AFTERNOON AND EARLY EVENING. THEN SUBZERO LOWS OUTSIDE OF DOWNTOWN CHICAGO AND NW INDIANA PLUS ONLY SLOWLY DIMINISHING WINDS WILL YIELD WIND CHILLS OF 20 TO 30 BELOW LATE SATURDAY NIGHT INTO SUNDAY MORNING. WILL IN ALL LIKELIHOOD NEED A WIND CHILL ADVISORY STARTING VALENTINES DAY EVENING. DRESS APPROPRIATE FOR DANGEROUS COLD IF YOU HAVE DINNER PLANS SATURDAY NIGHT OR CONSIDER SPENDING THE NIGHT IN WITH YOUR VALENTINE IF YOU HAVEN`T MADE PLANS YET! VERY GRADUAL WARM ADVECTION ON SUNDAY SHOULD ALLOW HIGHS TO RECOVER TO THE HIGH SINGLE DIGITS TO MID TEENS. LAKE EFFECT DISCUSSION FOR SATURDAY INTO SUNDAY...EXTREME 850 MB TO LAKE DELTA TS OF ABOUT 25C AND EQUILIBRIUM LEVELS AT OR OVER 10KFT ARE LIKELY TO RESULT IN IMPRESSIVE LAKE EFFECT SNOW BAND(S) DEVELOPING OVER SOUTHERN LAKE MICHIGAN. WILL STILL NEED TO ASSESS LATEST GUIDANCE CONCERNING OVERALL EVOLUTION...BUT GUIDANCE HAS REMAINED IN EXCELLENT AGREEMENT IN SWINGING BOUNDARY LAYER FLOW FROM NNW SATURDAY AFTERNOON AND EARLY EVENING TO NORTHERLY SATURDAY NIGHT AND THEN NORTH-NORTHEAST TO NORTHEAST ON SUNDAY. STEADY LAKE SNOWS COULD GET INTO PORTER COUNTY AS EARLY AS SATURDAY AFTERNOON. I THEN BROUGHT CATEGORICAL POPS WESTWARD SATURDAY NIGHT INTO SUNDAY MORNING...WITH ACTIVITY WEAKENING OVER NORTHEAST ILLINOIS DUE TO SUBSIDENCE AND INCREASINGLY DRY AIR ON SUNDAY AFTERNOON. POTENTIAL MESOLOW/ENHANCED CONVERGENCE COULD LET SNOW HANG ON A BIT LONGER THAN WOULD OTHERWISE EXPECT. WILL LIKELY NEED SOME SORT OF LAKE EFFECT HEADLINE AND WOULDNT BE SURPRISED WITH NEEDING ANOTHER WARNING FOR AT LEAST PORTER COUNTY GIVEN IMPRESSIVE PARAMETERS. AT LEAST 6 INCHES OF ACCUMULATION APPEAR POSSIBLE FOR THE NORTHERN HALF OF PORTER...WHICH COULD BE CONSERVATIVE. RC && .LONG TERM... 111 PM CST SUNDAY NIGHT THROUGH THURSDAY... HIGH AMPLITUDE RIDING REBUILDS YET AGAIN JUST OFFSHORE OF THE PACIFIC COASTLINE FOR THE EARLY HALF OF THE WEEK. AFTER SOME RECOVERY ON MONDAY...THIS PATTERN SUGGESTS WE WILL REMAIN IN A COLDER NW FLOW PATTERN WITH BELOW NORMAL TEMPERATURES AN OCCASIONAL CHANCE FOR LIGHT SNOW. SURFACE HIGH PRESSURE QUICKLY SHIFTS EAST ON SUNDAY NIGHT OPENING THE DOOR TO A SERIES OF DISTURBANCES IN WEST/NORTHWEST FLOW ALOFT. WARM AIR ADVECTION BEHIND THE DEPARTING HIGH MAY TRIGGER SOME LIGHT SNOW IN OUR WESTERN AREAS SUNDAY NIGHT...BUT THESE DISTURBANCES LOOK TO SPLIT THE AREA WITH ONE WAVES DIGGING SOUTH CLOSER TO THE LINGERING LOW LEVEL BAROCLINIC ZONE THAT BLASTED THROUGH THE AREA ON SATURDAY. SOME OF THIS MAY GRAZE OUR SOUTHERN COUNTIES FROM LASALLE EAST TO BENTON COUNTY INDIANA DURING THE DAY MONDAY. THE OTHER PACIFIC WAVE BY THIS TIME WOULD HAVE TAKEN A MORE ARCTIC ROUTE GRAZES OUR NORTHERN ZONES AND LARGELY PASSES BY TO OUR NORTH. THAT SAID...LIGHT ISENTROPIC LIFT AHEAD OF THE NORTHERN SHORTWAVE KEEPS CHANCES FOR LIGHT SNOW GOING FOR NORTH CENTRAL ILLINOIS MONDAY...THEN ALONG AND NORTH OF I-88 MONDAY NIGHT. MODELS ARE NOT IN GREAT AGREEMENT ABOUT ACCUMULATING SNOW WITH THE SPLIT ENERGY ON MONDAY/MONDAY NIGHT...THUS SOME LOW CHANCE POPS CARRIED. SHOULD BE A CLOUDIER PERIOD NONETHELESS. THE PATTERN THEN BECOMES HIGHLY AMPLIFIED OVER OUR REGION WITH LOW PRESSURE OVER HUDSON BAY WHILE A DEEP UPPER TROUGH DIGS INTO THE FOUR CORNERS REGION/DESERT SOUTHWEST. THE LEADING EDGE OF A COLD FRONT BEGINS OOZING IN TUESDAY. THESE TWO SYSTEMS EVENTUALLY MERGE INTO A UNIFIED TROUGH WHICH PASSES OVER THE REGION ON LATER TUESDAY AND TUESDAY NIGHT. MUCH OF THE FORCING WITH THIS WILL BE SOUTH OF THE AREA LEAVING US COLD AND DRIER WITH SOME LAKE EFFECT SNOWS IN NORTHWEST INDIANA. PICTURE GETS A BIT MORE MUDDLED SNOWFALL WISE MID TO LATE WEEK LEAVING US SUSCEPTIBLE TO CLIPPERS...BUT HAVE HIGHER CONFIDENCE IN CONTINUED COLDER WEATHER AND SOME LAKE EFFECT SNOW. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * CHANCE OF FLURRIES/LIGHT SNOW AND TEMPORARY MVFR CONDITIONS MID FRIDAY AFTERNOON THROUGH EARLY EVENING. * HIGHER CHANCE FOR A PERIOD OF SNOW SHOWERS REDUCING VISIBILITY TO IFR LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. * GUSTY NORTHWEST WINDS DEVELOPING LATE FRIDAY NIGHT BECOMING EVEN STRONGER EARLY SATURDAY MORNING WITH GUSTS TO AT LEAST 35 KNOTS. //DISCUSSION...UPDATED 06Z... A HIGH PRESSURE RIDGE WILL MOVE EAST OF THE AREA THROUGH FRIDAY MORNING WITH SOUTHWEST WINDS TO KICK IN AND STRENGTHEN INTO THE AFTERNOON. GUSTS SHOULD BE PERIODICALLY IN THE 18-25KT RANGE. CLOUDS WILL GRADUALLY THICKEN AND LOWER DURING THE MORNING AND EARLY AFTERNOON. UPSTREAM OBSERVATIONS INDICATE SOME LIGHT SNOW / FLURRIES WITHIN THIS AREA OF ASCENT AND EXPECT SIMILAR ACROSS EASTERN WI AND PROBABLY NORTHEAST IL AND NORTHWEST IN FRIDAY AFTERNOON AND EARLY EVENING. A BRIEF PERIOD OR TWO OF MVFR CONDITIONS IS POSSIBLE...NAMELY CIGS. LIMITED DEEP LAYER SATURATION SHOULD PREVENT ANY CONDITIONS WORSE THAN THIS DURING THAT TIME. A STRONG JET STREAM BUCKLE WILL DRIVE AN ARCTIC COLD FRONT ACROSS THE AREA LATE FRIDAY NIGHT SHIFTING WINDS NORTHWEST AND INCREASING SPEEDS. THESE WILL LIKELY JUMP UP EVEN FURTHER JUST AFTER SUNRISE SATURDAY. IN THE FEW HOUR WINDOW FOLLOWING THE FRONTAL PASSAGE...THE ATMOSPHERE LOOKS PRIMED FOR AT LEAST SCATTERED SNOW SHOWERS. GIVEN THE CONCURRENT WIND SPEEDS...IFR VISIBILITY WOULD BE FAVORED DIRECTLY UNDER ANY OF THESE SNOW SHOWERS. LIGHT ACCUMULATIONS OF UNDER ONE INCH ARE EXPECTED WITH THESE. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW-MEDIUM IN SNOW POTENTIAL AND INTENSITY FRIDAY AFTERNOON AND ATTENDANT MVFR CIGS POTENTIAL. * MEDIUM-HIGH IN SNOW SHOWER POTENTIAL LATE FRIDAY NIGHT INTO EARLY SATURDAY. MEDIUM-HIGH ON BRIEF PERIOD OF IFR. LOW ON EXACT TIMING. * HIGH IN WINDS. //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...PRIMARILY VFR. STRONG/GUSTY NORTHWEST WINDS. SUNDAY...CHANCE OF MVFR CIGS/FLURRIES. MONDAY THROUGH WEDNESDAY...PRIMARILY VFR. MTF/IZZI && .MARINE... 425 PM CST HIGHER WIND SPEEDS STILL IN PLACE ACROSS THE ENTIRE LAKE AS A FAIRLY TIGHT PRESSURE GRADIENT REMAINS OVERHEAD...WHILE HIGH PRESSURE MOVES SOUTHEAST OVER THE REGION. DO EXPECT THE GRADIENT TO RELAX RATHER QUICKLY THIS EVENING...AND WITH WINDS DIMINISHING WHILE BECOMING MORE WESTERLY. THESE LIGHTER WINDS WILL BE ON THE BRIEF SIDE AS SOUTHWEST WINDS INCREASE ONCE AGAIN ON FRIDAY OUT AHEAD OF AN APPROACHING LOW FROM THE NORTHWEST. EXPECT WINDS TO 30 KT ONCE AGAIN ON FRIDAY...BUT BECOMING MORE WEST AND NORTHWEST BY FRIDAY EVENING. DEPARTING LOW PRESSURE AND THEN BUILDING HIGH PRESSURE FROM THE NORTHWEST WILL ALLOW FOR WINDS TO CONTINUE INCREASING LATE FRIDAY NIGHT INTO SATURDAY MORNING...WITH GALES APPEARING LIKELY. HAVE NORTHWEST TO NORTH GALES TO 45 KT MENTIONED IN THE FORECAST...BUT COULD SEE AN UPWARD TREND OCCURRING WITH STORM FORCE WINDS DEFINITELY NOT OUT OF THE QUESTION DURING THE DAY ON SATURDAY. A GALE WATCH HAS BEEN ISSUED FOR THE OPEN WATERS AND THE NEARSHORE WATERS DURING THIS TIME...WITH WINDS DIMINISHING SATURDAY NIGHT. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 4 AM FRIDAY. GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...6 AM SATURDAY TO 3 AM SUNDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 3 AM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1107 PM CST Thu Feb 12 2015 .UPDATE... ISSUED AT 830 PM CST THU FEB 12 2015 Arctic high pressure centered over our area early this evening has allowed winds to subside with an increase in cirrus from northwest to southeast as our next weather system moves into the Missouri River Valley. Early evening temperatures have fallen off but not as quickly as thought as the thicker cirrus has kept the numbers in check early this evening. Weather system to our west responsible for the increase in clouds this evening was producing some scattered areas of light snow over west central and southwest Iowa this evening with both the HRRR and Rapid Refresh models keeping the light snows to our west before it diminishes as it heads east into extreme west central IL Friday morning. Current forecast has this well handled this evening, so other than the usual tweaks to the early evening temperatures, no other changes were needed that would require an updated ZFP at this time. && .SHORT TERM...(Tonight) ISSUED AT 252 PM CST THU FEB 12 2015 Latest water vapor imagery shows broad northwesterly flow over the Midwest, with numerous weak short-waves embedded within the pattern. Next wave of interest to the weather across central Illinois is currently located over western North Dakota and is expected to track S/SE to the Missouri/Iowa border by 12z. 20z/2pm surface obs show light snow falling along/ahead of this feature across the Dakotas. As the wave tracks southeastward, it is expected to shear/weaken with time, resulting in only very minor lift arriving across the western KILX CWA late tonight. With forecast soundings remaining unsaturated, have opted to remove mentionable PoPs overnight in favor of just a chance of flurries along/west of a Galesburg to Jacksonville line. Given initially mostly clear skies and diminishing winds, temperatures will quickly bottom out in the single digits and teens by mid to late evening. As clouds increase and a light southerly return flow begins to develop late, readings will likely rise a couple of degrees toward dawn, especially west of the I-55 corridor. && .LONG TERM...(Friday through Thursday) ISSUED AT 252 PM CST THU FEB 12 2015 An extended period of colder to much colder than normal conditions is expected across central and southeast Illinois, lingering at least through the end of next week. Persistent ridging up to Pacific coast into Alaska and downstream troffing over at least the eastern half of North America will help ensure this fact. Periodic waves in the predominantly northwest upper-level level flow will be accompanied by reinforcing shots of cold air, and possibly some light snow or flurries. The upper troffing will dig enough to our west by next Monday/Tuesday to at least pose the risk of a stronger system moving our way, but recent model trends have been pushing this system further south. Temperatures will briefly moderate Friday ahead of our next major clipper type wave for Saturday. A weaker wave will pass mainly to our north of Friday, which may bring some flurries to northern sections of the forecast area, but no significant snowfall is anticipated. Saturday`s clipper is potent, but will pass far enough to our north/east to be a minimal snowfall threat. The more notable impact with its passage will be winds gusting over 30 mph Saturday into Saturday night. These winds will help usher in bitterly cold sub-zero wind chill temperatures for the entire forecast area Saturday night into Sunday. A few waves in the broader North American trof expected to be in place for early next week will come toward the area from a more westerly or even southwesterly direction. This track should allow these waves to have more moisture to work with as far as being snow producers. However, model trends have pushed the main baroclinic zone/storm track much further south, which should greatly diminish the local threat of significant snow accumulation Monday into Tuesday. Since the system/systems with the early week waves has/have the potential to be significant, will continue to keep a close eye on later guidance. However, at this point, the model trends are looking more optimistic as far as keeping the significant precipitation away from the forecast area. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1100 PM CST THU FEB 12 2015 VFR conditions are expected to continue through Friday evening. High pressure was drifting slowly away from our area late this evening while a weak weather disturbance over the Missouri Valley has produced some light snow over western Iowa into northwest Missouri. We have seen an increase in mid and high level clouds from the northwest this evening and these clouds are expected to hold overnight. As a weather disturbance passes to our north Friday clouds will drop to low VFR in a few locations with a few of the models indicating the potential for a few flurries, mainly across our northern TAF sites late tomorrow morning into the afternoon hours before the disturbance shifts off to our east by evening. Surface winds will be light and variable tonight and then shift into a southerly direction at 10 to 15 kts Friday morning. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Smith SHORT TERM...Barnes LONG TERM...Bak AVIATION...Smith
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1053 PM CST THU FEB 12 2015 .SHORT TERM /TONIGHT/... ISSUED AT 350 PM CST THU FEB 12 2015 LIGHT SNOW IS DEVELOPING ACROSS SOUTH DAKOTA AHEAD OF A SHORT WAVE DROPPING SOUTHEAST THROUGH NORTH DAKOTA. THE VERTICAL ASCENT IS BEING ENHANCED BY MID LEVEL THETA E ADVECTION IN ADDITION TO THE KINEMATICS ASSOCIATED WITH THE SHORT WAVE. THIS FORCING WILL ARRIVE ACROSS NORTHWEST IOWA BY LATE THIS AFTERNOON AND ARRIVE INTO THE CENTRAL PORTION OF THE STATE BY THIS EVENING. SOME DISCONTINUITY BETWEEN THE PERIOD OF PEAK FORCING AND TIMING OF MAX SATURATION THROUGH THE COLUMN. THE DISCONTINUITY IS DUE TO THE INITIAL FORCING BEING SPENT TRYING TO SATURATE THE DRY LOW LEVELS LEFT OVER FROM THE DEPARTING HIGH PRESSURE SYSTEM. LIGHT SNOW IS LIKELY WITH MINOR ACCUMULATIONS...GENERALLY ONE HALF INCH OR LESS. WINDS WILL SWITCH TO THE SOUTH OVERNIGHT AS THE HIGH DEPARTS. TEMPERATURES WILL BE STEADY TO RISING AFTER 06Z. .LONG TERM /FRIDAY THROUGH THURSDAY/... ISSUED AT 350 PM CST THU FEB 12 2015 ALTHOUGH THERE MAY BE SOME MINOR MODERATION LATE...THERE IS STILL NO SIGN OF SIGNIFICANT PATTERN CHANGE THROUGH THE PERIOD WITH MEAN TROUGH INTO THE CENTRAL OR ERN CONUS. TEMPS WILL BRIEFLY REBOUND BACK TO NORMAL FRI...WITH LINGERING EARLY MORNING WARM ADVECTION LIGHT SNOW POSSIBLY FAR NE...BUT A SHORT WAVE/PV ANOMALY PASSAGE MUCH LIKE YESTERDAY WILL DRIVE ANOTHER COLD FRONT AND SUBSEQUENT SURGE OF ARCTIC AIR THROUGH THE STATE INTO THE NIGHT. TRAILING LOBE OF FORCING MAY PRODUCE SOME TOKEN LIGHT SNOW BUT FORCING AND MOISTURE IS DISJOINTED AND NEVER REALLY PHASES. ICE BEARING LIFT IS FAIRLY TYPICAL ALOFT AT ONSET BUT FAVORED DENDRITIC GROWTH ZONE /DGZ/ TEMPS CRASH WITH COLD AIR ADVECTION INTO EARLY SAT MORNING WITH STRATUS POTENTIALLY PRODUCING LOW BASED LIGHT SNOW OR FLURRIES. MSLP GRADIENT AND MIXED LAYER WINDS WILL BE PUSHING ADVISORY CRITERIA...MAINLY SUSTAINED /26KTS/...DURING THE MORNING NE. SAT NIGHT LOOKS QUITE COLD WITH READINGS BELOW ZERO NE TWO-THIRDS ALTHOUGH INCREASING CLOUDINESS WITH WEAK WARM ADVECTION MAY TEMPER THINGS SOMEWHAT. RECENT ECMWF/GFS TRENDS NOW SUGGEST NRN STREAM WILL BE MORE DOMINATE EARLY NEXT WEEK WHICH LEADS TO TWO SENSIBLE WEATHER CHANGES. THE FIRST WILL BE THE ADDITION OF LOW END POPS AROUND SUN...AT LEAST FOR A START...WITH MAIN FOCUS NORTH. FORCING IS FAIRLY DEEP WITH CERTAINLY ADEQUATE MOISTURE FOR PRECIP. QPF AMOUNTS ARE FAIRLY LOW WITH THIS SYSTEM...WHICH WOULD BE EXPECTED IN THIS COLD AIRMASS...HOWEVER SNOW RATIOS MAY BE GREATLY INFLATED WITH DGZ DEPTH AROUND 10KFT AND BRIEFLY PHASED WITH ZONE OF MAX OMEGA. COBB SNOW RATIOS REFLECT THIS AS WELL...JUMPING INTO THE 20S. IF CURRENT TRENDS CONTINUE SUN WILL CERTAINLY NEED TO BE WATCHED WITH HIGHER POPS AND AMOUNTS NEEDED. THIS MORE NRN STREAM EMPHASIS HAS ALSO LOWERED HEIGHTS AND PUSHED THE PREVIOUSLY ANTICIPATED MON/MON NIGHT SOUTHERN SNOW FARTHER AWAY FROM FORECAST AREA. THERE ARE STILL LOW POPS IN THE FORECAST...BUT THIS IS LIKELY MORE A REFLECTION OF 00Z ECMWF INFLUENCE THAN ANYTHING AND COULD VERY WELL BE LESSENED FURTHER OR REMOVED ALTOGETHER IF THE 12Z GFS HOLDS TRUE AND 12Z ECMWF GETS INTO THE MIDNIGHT SHIFT FORECAST. OTHERWISE THE REMAINDER OF THE FORECAST LOOKS DRY WITH PERSISTENT BELOW NORMAL TEMPERATURES WITH JET STAYING AWAY FROM IA IN HEART OF TROUGH THROUGH AT LEAST THU. ALTHOUGH THE 12Z ECMWF IS LESS AGGRESSIVE...POPS MAY NEED TO BE ADDED AROUND WED IF THE MORE BULLISH 12Z GFS MAINTAINS ITSELF. && .AVIATION...13/06Z ISSUED AT 1054 PM CST THU FEB 12 2015 LIGHT SNOW MAKING LITTLE EAST PROGRESS WITH FORCING AND LIFT CONCENTRATED WEST OF I35 AS LACK OF SATURATION EAST OF I35 CONTINUES. HRRR SHOWS DRAMATIC WEAKENING OF BAND...SO ALONG WITH CURRENT TRENDS HAVE CUT BACK ON COVERAGE AND LIMITED VSBY REDUCTIONS AND CIG LOWERING THROUGH 12Z. SOME BKN MID LEVEL CLOUDS REMAIN THROUGH DAY PRIOR TO ARRIVAL OF ARCTIC BOUNDARY AND POSSIBLE -SN AGAIN TOWARD END OF PERIOD AS FRONT CROSSES THE REGION BY 14/06Z. STRONG NW WINDS TO DEVELOP LATE IN THE PERIOD MAINLY AFT 14/03Z NORTH SECTIONS. /REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DONAVON LONG TERM...SMALL AVIATION...REV
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1250 AM EST FRI FEB 13 2015 .SYNOPSIS... ARCTIC AIR WILL POUR DOWN FROM CANADA TONIGHT, PRODUCING DANGEROUS WIND CHILLS OVERNIGHT INTO FRIDAY AFTERNOON. A STORM SYSTEM SLIDING OUT OF THE GREAT LAKES WILL BRING A FEW INCHES OF SNOW ON SATURDAY, WITH THE COLDEST AIR SO FAR THIS WINTER TO FOLLOW FOR SUNDAY. && .NEAR TERM /THROUGH TODAY/... 1030 PM UPDATE... DRY AIR HAS WEAKENED THE CENTRAL NY SNOW BAND FROM JUST A FEW HOURS AGO AND OUR FLOW IS FINALLY BECOMING MORE NORTHWEST. THE RESPONSE IS A SPRAY OF MULTI BAND LAKE SNOWS, EXTENDING ALL THE WAY INTO THE POCONOS OF NEPA. MAIN UPDATE WAS TO INCREASE SNOW AMOUNTS IN NEPA INTO THE DUSTING TO 2" RANGE. THE COMBINATION OF WIND AND SNOW WILL CONTINUE TO PRODUCE LOW VSBYS FOR THE NEXT FEW HOURS. USED A LAV/HRRR BLEND FOR TEMPS. WE ARE ALREADY AT ZERO HERE AT THE OFFICE, WITH SUSTAINED WINDS OF 20 MPH. WIND CHILL WARNING LOOKS GOOD. PREVIOUS AFD IS BELOW. 550 PM UPDATE... TEMP FORECAST ON TRACK WITH SINGLE NUMBERS ALREADY IN OUR FAR WEST. LATEST HRRR SEEMS TO HAVE A GREAT HANDLE ON FALLING TEMPS THIS EVENING, AND OUR CURRENT FORECAST MATCHES THIS VERY WELL. I DID TWEAK SNOW AMOUNTS AND POPS FOR THE NEXT FEW HOURS AS THE BAND OVER OSWEGO COUNTY HAS NOT MOVED AS FAR SOUTH AS ANTICIPATED. OVERALL A QUICK COATING TO AN INCH IS POSSIBLE OVER MUCH OF THE AREA THROUGH THIS EVENING AS COLDER AIR CONTINUES TO POUR INTO THE AREA, WITH ON AND OFF SNOW SQUALLS. WHILE AMOUNTS ARE NOT HIGH, SNOWFALL RATES AND INCREASING WIND WILL CREATE LOW VSBYS FROM TIME TO TIME. LOCALLY HIGHER AMOUNTS OF 2" TO 4" POSSIBLE ALONG THE SHORELINE OF ONEIDA LAKE IN PLACES LIKE SYLVAN BEACH, AND JEWELL, BUT THE HIGHER TOTALS WILL BE MORE IN OSWEGO COUNTY ITSELF. PREVIOUS AFD IS BELOW. 115 PM UPDATE... POWERFUL CAA WILL INCREASE THROUGH THE EVENING HOURS, WITH SURFACE TEMPERATURES EXPECTED TO FALL 10 TO 15 DEGREES IN JUST A MATTER OF A FEW HOURS. 925 MB TEMPS WILL FALL TO -21C AT BGM BY 6Z AND TO -24C BY 12Z. STRONG GRADIENT WILL KEEP WINDS BETWEEN 12 AND 18 MPH OVERNIGHT, WHILE GUSTS CONTINUE AROUND 25 MPH. THE COMBINATION OF WIND AND WELL BELOW TEMPERATURES WILL PRODUCE RARE WIND CHILL WARNING CRITERIA APPARENT TEMPERATURES...MAINLY BETWEEN -25F AND -30F. ADVISORY CRITERIA APPARENT TEMPERATURES SHOULD HOLD INTO FRIDAY AFTERNOON. 1055 AM UPDATE... WEAK CAA HAS BEGUN THROUGH THE FA. TEMPERATURES WILL HOLD STEADY OR SLIGHTLY FALL THROUGH THE NEXT 3 TO 5 HOURS. FAR MORE POWERFUL CAA WILL COMMENCE LATER THIS AFTERNOON AND ACCELERATE AFTER SUNSET. MADE MINOR ADJUSTMENTS TO TEMPERATURE TRENDS AND ALTERED THE GRIDDED POPS/WX BASED ON LATEST NAM12 PROGS. OTHERWISE THE FORECAST IS IN EXCELLENT SHAPE. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... 200 PM UPDATE... FRIGID APPARENT TEMPERATURES REMAIN IN PLACE THROUGH FRIDAY AFTERNOON. LIGHT LAKE EFFECT SNOW SHOWERS TO THE NORTH WILL TAPER OFF AS WINDS SHIFT AND DIRECTIONAL SHEAR INCREASES. ON SATURDAY, A POWERFUL CYCLONE WILL DROP OUT OF THE GREAT LAKES. GIVEN THE AMOUNT OF COLD AIR, IT SHOULD COME AS NO SURPRISE THAT THE SNOW GROWTH AREA IS MAXIMIZED. HOWEVER MOISTURE IS LIMITED, SO DESPITE THE STRENGTH OF THE STORM, WE ARE FORECASTING A BORDERLINE ADVISORY/NO-ADVISORY EVENT, WITH 3 TO 4 INCHES OF SNOW ACCUMULATION OVER AN 18 HOUR PERIOD. A STAGGERING AMOUNT OF ARCTIC AIR POURS DOWN BEHIND THE CYCLONE. AT THE SAME TIME, THE CYCLONE EXPLODES ALONG THE ATLANTIC COAST WHILE THE DOME OF HIGH PRESSURE SLIDES DOWN FROM THE UPPER MIDWEST. AS A RESULT, A STEEP PRESSURE GRADIENT WILL DEVELOP. THE COMBINATION OF FRIGID TEMPERATURES SATURDAY NIGHT INTO SUNDAY LOOKS QUITE DANGEROUS. APPARENT TEMPERATURES BELOW -30F ARE ANTICIPATED. 925MB TEMPS AT BGM ARE AROUND -23C ON SUNDAY, SO MOST AREAS WILL SEE MAX TEMPERATURES AROUND ZERO DEGREES. THE HILLTOPS AND THE NORTHERN FA WILL BE EVEN COLDER. 350 AM EST UPDATE... FRIDAY WILL FEEL MISERABLY COLD AS WELL AS 850MB TEMPS WILL ONLY MODERATE BY A COUPLE OF DEGREES. HIGH PRESSURE WILL BUILD OVER THE REGION ON FRI DURING THE DAY WHICH WILL PUT AN END TO LAKE EFFECT SHOWERS OVR NY. TEMPS FRIDAY AFTERNOON ARE EXPECTED TO RISE SLIGHTLY ABOVE ZERO. TEMPS LATE FRI NIGHT/SAT MORNING ARE EXPECTED TO BE VERY ALSO. MAY NEED TO ISSUE AN ADDITIONAL ADVISORY FOR THIS TIME FRAME... BUT WILL HOLD OFF FOR NOW. THE NEXT STORM SYSTEM WILL START TO IMPACT THE CWA SATURDAY MORNING. STRONG WAA WILL TAKE PLACE AHEAD OF THE SYSTEM RESULTING IN TEMPS RISING INTO THE LOW MID 20S. THIS SYSTEM MAY BRING WIDESPREAD SNOW TO THE CWA AND POSSIBLY ADVISORY SNOWFALL AMOUNTS. WILL KEEP CLOSE EYE ON EVOLUTION OF THIS STORM. THE COLD FRONT ATTENDANT WITH THIS SYSTEM WILL SURGE THROUGH THE CWA ON SUNDAY. THE AIRMASS BEHIND THIS SYSTEM WILL BE EVEN COLDER THAN THE AIRMASS EXPECTED TO MOVE THROUGH LATE TONIGHT. DANGEROUS WIND CHILL VALUES MAY BE LIKELY AGAIN LATE SAT NIGHT. WIND CHILL VALUES OF NEGATIVE 30 MAY BE POSSIBLE. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIPRES BLDS IN ON MON BRINGING AN END TO ANY LEFTOVER LE IN CNTRL NY. RDGG REMAINS IN CNTRL THRU TUE WITH A SLOW MODERATION IN TEMPS UNDER GNRLY CLR SKIES...ALTHOUGH BLO ZERO TEMPS STILL VERY PSBL OVERNIGHT. NEXT SYSTEM APRCHS FOR TUE AND WED WITH THE GFS AND EURO IN FAIR AGREEMENT. ESSENTIALLY A SRN STREAM WV GRABS GULF MOISTURE AND PHASES WITH A SHRT WV DROPPING SEWRD IN THE NRN STREAM TO DVLP A SIGNIFICANT SFC LOW OVER THE SE US LATE TUE AND EARLY WED. SYSTEM THEN RIDES THE SW FLOW TO A PSN NEAR JERSEY CST LTR WED. THIS BRINGS THE PSBLTY OF COASTAL RAIN BUT A MORE SIGNIFICANT SNOW INLAND AND OVER THE BGM FCST AREA LATE TUE INTO WED. MODEL DFRNCS INCLUDE THE USUAL SPEED ISSUES...AND THAT THE EURO SHOWS A WEAKER AND MORE SHEARED SFC LOW WHILE THE 12Z GFS SHOWS A MORE CONSOLIDATED LOW AND A STRONGER INV TROF BACK OVER THE FCST AREA. IN ANY EVENT...PLENTY OF TIME AND PLENTY TO WATCH FOR FOR THE NEXT STORM IN THE AREA. FLWD HPC GUID FOR TEMPS WHICH MATCHED WELL WITH THE PRVS FCST AND SURROUNDING OFFICES. FOR SOME REASON...HPC HAS BEEN DOWNPLAYING THE PTNL FOR LE IN THE WAKE OF THE WEEKEND SYSTEM SO HAVE BUMPED UP POPS FOR THAT PSBLTY. FLWD HPC MORE CLOSELY FOR THE APRCHG SYSTEM AT THE END OF THE PD. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... 06Z FRI UPDATE... PERSISTENT MULTI-BAND LES WILL CONTINUE TO BRING OCNL IFR RESTRICTIONS AT KSYR/KITH/KBGM THROUGH AT LEAST 12-15Z. RESTRICTIVE CONDS AT KELM/KAVP SHOULD BE TEMPORARY...ENDING BY ARND 08Z...WHILE KRME REMAINS VFR. DURG THE LATE MRNG/EARLY AFTN PD (15-21Z)...OTHER THAN RESIDUAL MVFR RESTRICTIONS AT KSYR...VFR SHOULD PREVAIL AREA-WIDE. LATE IN THE DAY (21Z-00Z SAT)...A RELATIVELY BRIEF PD OF IFR VSBY`S IS EXPECTED AT KSYR/KRME...AS A LES BAND LIFTS BACK THROUGH THE RGN. OTHWS...VFR SHOULD CONTINUE THROUGH THE END OF THE VALID TAF PD (06Z SAT). .OUTLOOK... SAT...RESTRICTIONS FROM -SHSN AND POSSIBLE SNOW SQUALLS. SUN...RESTRICTIONS POSSIBLE FROM -SHSN...MAINLY CNY. MON...MAINLY VFR. TUE...COASTAL LOW POSSIBLY PRODUCING -SN AND ASSOCIATED RESTRICTIONS... ESPECIALLY LATE TUE-TUE NGT. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WIND CHILL WARNING UNTIL 4 PM EST THIS AFTERNOON FOR PAZ038>040-043-044-047-048-072. NY...WIND CHILL WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...DJP NEAR TERM...DJP/HEDEN SHORT TERM...DJP LONG TERM...DGM AVIATION...MLJ/MDP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1251 AM CST FRI FEB 13 2015 .UPDATE... ISSUED AT 1251 AM CST FRI FEB 13 2015 CLOUDS HAD CLEARED THROUGH JAMESTOWN...AND TEMPERATURES IN SOUTH CENTRAL NORTH DAKOTA REMAINED FROM 5-10F...WHILE TEMPERATURES IN THE FAR WEST HAD RISEN TO AROUND 30F WITH LIGHT WESTERLY WINDS. EXPECT RISING TEMPERATURES IN CENTRAL NORTH DAKOTA EARLY THIS MORNING AS WARM ADVECTION CONTINUES PUSHING EASTWARD. ADJUSTED MINIMUM TEMPERATURES ACCORDINGLY. UPDATE ISSUED AT 924 PM CST THU FEB 12 2015 AT 9 PM CST CLOUDS HAVE CLEARED THROUGH A RUGBY TO STEELE TO WISHEK LINE THIS EVENING AS WARM ADVECTION ERODES AND TRANSLATES THE CLOUD DECK. EXPECT THE CLOUDS TO CLEAR JAMESTOWN BY 1 AM CST. SEEM TO BE ENOUGH MIXING IN THE BOUNDARY LAYER TO HOLD TEMPERATURES UP TONIGHT IN SPITE OF THE CLEARING. CURRENT FORECAST MINS LOOK OK. ADJUSTED CLOUDS TO FIT THE TREND. UPDATE ISSUED AT 627 PM CST THU FEB 12 2015 DECREASED POPS ACROSS THE SOUTHEAST AND DECREASED CLOUD COVER AS THE CLOUD DECK IS PUSHING SOUTHEAST FASTER THAN ORIGINALLY FORECAST. OTHERWISE FORECAST REMAINS ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 400 PM CST THU FEB 12 2015 SNOW ENDING THIS EVENING SOUTHEAST AND LIGHT SNOW ON FRIDAY HIGHLIGHT THE SHORT TERM. LIGHT SNOW FOCUSED ACROSS THE JAMES RIVER VALLEY AS OF 2130 UTC WILL CONTINUE TO QUICKLY DIMINISH BY EARLY THIS EVENING BASED UPON RADAR TRENDS AND THE 19 UTC HRRR SIMULATED REFLECTIVITY. THE 12 AND INCOMING 18 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT ON A BAND OF LIGHT SNOW DEVELOPING ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA DURING THE DAY ON FRIDAY IN ASSOCIATION WITH THE BAROCLINIC ZONE ON THE LEADING EDGE OF THE NEXT ARCTIC HIGH THAT WILL PROPAGATE INTO THE NORTHERN PLAINS FRIDAY AFTERNOON AND EVENING. SNOWFALL AMOUNTS OF LESS THAN ONE INCH ARE EXPECTED. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 400 PM CST THU FEB 12 2015 A COLD FRONT IS EXPECTED TO SWING THROUGH THE AREA FRIDAY. SOME LIGHT SNOW IS POSSIBLE ALONG THE FRONT AS SURFACE LOW PRESSURE DEVELOPS ACROSS EASTERN MONTANA. COLD CANADIAN AIR WILL THEN FILTER INTO THE REGION FRIDAY NIGHT INTO SATURDAY. WIND CHILL HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER SATURDAY. THE LATEST 12 UTC MODELS CONTINUE THE TREND OF PREVIOUS RUNS...WITH A SHORTWAVE AND INVERTED TROUGH SLIDING THROUGH WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH SUNDAY. WIDESPREAD SNOW AMOUNTS BETWEEN ONE AND FOUR INCHES APPEAR LIKELY BY SUNDAY EVENING. NORTHERN NORTH DAKOTA APPEARS TO BE FAVORED TO RECEIVE THE HIGHEST SNOWFALL TOTALS WITH THIS EVENT. SCATTERED SNOW COULD LINGER THROUGH MONDAY AS STRONG COLD AIR ADVECTION TAKES HOLD. THE ECMWF CONTINUES ITS DRY AND COLD FORECAST MONDAY NIGHT THROUGH WEDNESDAY. HOWEVER THE LATEST GFS RUN BRINGS A CLIPPER THROUGH NORTH DAKOTA WEDNESDAY AND PRODUCES SOME LIGHT SNOW. WIND CHILL HEADLINES MAY BE NEEDED MONDAY NIGHT AND TUESDAY NIGHT FOR AREAS EAST OF THE MISSOURI RIVER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1251 AM CST FRI FEB 13 2015 AT MIDNIGHT CST...WEAK HIGH PRESSURE EXTENDED ACROSS THE WESTERN DAKOTAS AS A TROUGH OF LOW PRESSURE WAS RETREATING THROUGH MINNESOTA. MVFR CLOUDS AT KJMS ARE EXPECTED TO CLEAR TO VFR AROUND 06Z. OTHERWISE VFR ACROSS THE REGION AT 06Z. THE NEXT COLD FRONT TO AFFECT THE REGION EXTENDED FROM A LOW IN NORTHERN MANITOBA SOUTHWESTWARD ACROSS SOUTHERN SASKATCHEWAN. MVFR CIGS IN SOUTHERN MANITOBA AND SOUTHERN SASKATCHEWAN ARE EXPECTED TO MOVE INTO KMOT AND KJMS AROUND/AFTER 12Z...AND THEN EXPAND WESTWARD TO KISN AND KBIS BY AROUND 18Z...AND KDIK BY AROUND 21Z. THE COLD FRONT AND ASSOCIATED STRONG COLD ADVECTION BRING A CHANCE FOR SNOW ACROSS WESTERN NORTH DAKOTA FRIDAY AFTERNOON AND EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...AYD LONG TERM...AJ AVIATION...JV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CST THU FEB 12 2015 .UPDATE... ISSUED AT 911 PM CST THU FEB 12 2015 THE MAIN FOCUS THIS EVENING IS ON THE SNOW CHANCES OVERNIGHT INTO FRIDAY. CURRENTLY...A BAND OF SNOW HAS DEVELOPED ALONG THE SOUTH DAKOTA/MINNESOTA BORDER AND IS TRAILING TO THE SOUTHEAST AND DIMINISHING AS IT GOES INTO WESTERN IOWA. THE NORTHERN EDGE OF IT IS FADING QUICK AS WELL...SO THE QUESTION IS WITH WHETHER THERE WILL BE ANY REDEVELOPMENT ALONG THIS BROAD LOW LEVEL WARM AIR ADVECTION DRIFTING EAST ACROSS THE REGION. RAP THERMAL PROFILES HAVE TRENDED TOWARD BEING MORE SATURATED WITH ENOUGH LIFT TO PRODUCE SOME LIGHT SNOW AS THE WAA COMES THROUGH. BASED ON THE 12.12/18Z NAM/GFS/ECMWF/GEM...THERE APPEARS TO BE TWO MAIN AREAS OF 850MB WAA WITH THE FIRST BEING ON THE BAND OF SNOW CURRENTLY OFF TO THE WEST AND ANOTHER DROPPING DOWN ACROSS NORTHERN MINNESOTA/WISCONSIN. IT APPEARS THAT OUR BEST SHOT AT SNOW COMES WITH THIS SECOND SHOT OF WAA WHICH COMES IN SLOWER THAN PREVIOUS TRENDS. SO...HAVE SLOWED DOWN THE SNOW CHANCES FOR OVERNIGHT INTO TOMORROW BUT KEPT AMOUNTS THE SAME AT LESS THAN AN INCH. && .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 251 PM CST THU FEB 12 2015 MAIN FCST CONCERNS THIS PERIOD...-SN CHANCES LATE TONIGHT/FRI MORNING...FLURRY/-SHSN CHANCES WITH ARCTIC FRONTAL PASSAGE FRI NIGHT...WINDS LATE FRI NIGHT...TEMPERATURES. 18Z DATA ANALYSIS HAD A 1036-1040MB CAN/ARCTIC HIGH FROM SOUTHWEST ONT TO EASTERN KS...DRIFTING SLOWLY SOUTHEAST ACROSS THE MID/UPPER MS VALLEY. GENERALLY CLEAR/SUNNY SKIES ACROSS MN/IA/WI UNDER THE HIGH...WITH ONLY SOME HIGH CLOUDS AHEAD OF THE NEXT NORTHWEST FLOW SHORTWAVE SPREADING OVER WESTERN MN. WINDS WERE LIGHT WITH WIND CHILLS ABATING. EVEN WITH THE SUNSHINE...MID-DAY TEMPS ACROSS MUCH OF MN/IA WI ONLY IN THE -10F TO +10F RANGE...SOME 10F-20F BELOW NORMAL. 12.12Z MODELS INITIALIZED WILL AND PRESENT VERY SIMILAR SOLUTIONS FOR TONIGHT THRU FRI NIGHT AS 2 NORTHWEST FLOW SYSTEMS IMPACT THE REGION. TREND IS A LITTLE FLATTER/WEAKER WITH A SHORTWAVE TO RIPPLE SOUTHEAST ACROSS THE REGION LATER TONIGHT/EARLY FRI...THEN A LITTLE STRONGER/SLOWER WITH THE SHORTWAVE TO DROP IN FRI NIGHT. GIVEN THE TIGHT CONSENSUS...SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE. FOR THE SHORT TERM...ALL MODELS SHOWING MID/HIGH LEVEL MOISTURE AT ABOVE 700MB TO INCREASE/THICKEN OVER THE REGION TONIGHT AS LOWER LEVEL WARM ADVECTION GRADUALLY SPREADS EAST ACROSS THE AREA. PREVIOUS FORECASTER TRENDED TONIGHTS LOWS LATE THIS EVENING THEN STEADY/SLOWLY RISING OVERNIGHT...WHICH LOOKS GOOD. TIGHT SIGNAL FOR THE 925-700MB MOISTURE IN THE WARM ADVECTION/LIFT AHEAD OF THE LOWER LEVEL WAVE TO SPREAD INTO THE WEST END OF THE FCST AREA AROUND 06Z...NOT REACHING THE EAST END OF THE FCST AREA UNTIL AROUND 12Z FRI. WEAKER/FLATTER TREND OF THE SHORTWAVE RESULTS IN LESS OF A LIFTING SIGNAL ACROSS THE AREA LATER TONIGHT/FRI. ALL MODELS HAVE TRENDED DRIER WITH THE QPF SINCE THE 11.12Z RUNS...BUT STILL MANAGE TO SQUEEZE OUT SOME VERY LIGHT QPF AS THE ROUND OF LOWER LEVEL THERMODYNAMIC FORCING PUSHES ACROSS THE FCST AREA. LIMITED -SN CHANCES TO WHEN THE 925-700MB MOISTURE MOVES INTO/ACROSS THE FCST AREA...AFTER MIDNIGHT TONIGHT THRU MAINLY FRI MORNING. MEASURABLE SNOW CHANCES IN THE 30-40 PERCENT 06-18Z FRI LOOK GOOD FOR NOW. APPEARS AROUND 1/2 INCH OF SNOW WOULD BE POSSIBLE IF THE STRONGER... MORE SATURATED OF THE MODELS WERE TO VERIFY. A WARMER DAY FRI WITH HIGHS NEAR NORMAL AS 925MB TEMPS WARM INTO THE -6C TO -9C IN THE WARM ADVECTION WESTERLY FLOW. WARMUP IS SHORT LIVED AS NEXT STRONG SHORTWAVE DROPS ACROSS LK SUPERIOR AND DRIVES A STRONG ARCTIC FRONT SOUTH ACROSS THE AREA FRI NIGHT. SFC-850MB LAYER GENERALLY REMAINS SATURATED FRI NIGHT...WITH SOME WEAK LIFT TO ACCOMPANY THE FRONT AS THE COLD ADVECTION PUTS THE SQUEEZE ON THE WATER HOLDING CAPACITY OF THE LOWER PORTION OF THE COLUMN. ADDED SCT FLURRY MENTION TO GRIDS FOR FRI NIGHT. 925MB TEMPS CRASH BACK INTO THE -16C TO -21C RANGE AFTER MIDNIGHT FRI NIGHT...WITH TEMPS A FEW DEGREES EITHER SIDE OF 0F BY 12Z SAT. THIS WITH GRADIENT WINDS AROUND 20KTS GUSTING 30-35KTS PRODUCING WIND CHILLS OF -10 TO -25 BY 12Z SAT. MAY YET NEED A WIND CHILL ADVISORY FOR NORTHERN PORTIONS OF THE FCST AREA LATE FRI NIGHT. FAVORED THE MODEL/ENSEMBLE CONSENSUS OF LOWS/HIGHS FOR TONIGHT THRU FRI NIGHT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 251 PM CST THU FEB 12 2015 FCST CONCERNS FOR SATURDAY THRU SUN NIGHT...COLD TEMPERATURES AS ARCTIC HIGH PRESSURE DRIFTS ACROSS THE UPPER MIDWEST...-SN CHANCES IN RETURNING WARM ADVECTION SUN NIGHT. 12.12Z MODELS IN GOOD AGREEMENT AS THE FRI NIGHT SHORTWAVE ROTATES QUICKLY SOUTHEAST/OUT OF THE REGION. TIGHTER CONSENSUS FOR SLOW HGT RISES LATER SAT/SAT NIGHT AS TROUGHING DEEPENS ALONG THE EAST COAST AND AHEAD OF ANOTHER SHORTWAVE PASSING NEAR LK WINNIPEG BY 12Z SUN. HGTS FALL AGAIN SUN/SUN NIGHT AS THIS ENERGY CARVES OUT MORE BROAD TROUGHING OVER THE NORTH-CENTRAL CONUS. SOME SHORTWAVE DETAIL DIFFERENCES BY SUN/SUN NIGHT BUT TREND IS FOR MORE TROUGHING/ SHORTWAVE ENERGY OVER THE NORTHERN PLAINS/UPPER MIDWEST FOR LATER SUN/SUN NIGHT. FCST CONFIDENCE IN THE SAT THRU SUN NIGHT PERIOD IS GOOD THIS CYCLE. 1040MB OR HIGHER ARCTIC HIGH TO BUILD ACROSS THE UPPER MIDWEST SAT THRU SUN. TIGHT PRESSURE GRADIENT AND COLD ADVECTION ON THE FRONT SIDE OF THE HIGH IS OVER THE AREA SAT. 925MB TEMPS PROGGED TO DROP INTO THE -20C TO -25C RANGE BY 00Z SUN AND REMAIN THERE SAT NIGHT. WITH NORTHWEST WINDS AROUND 20KTS GUSTING 25-35KTS MUCH OF SAT... TEMPS WILL STRUGGLE TO WARM MUCH IF AT ALL. IF FRI NIGHT COLD ADVECTION IS DELAYED A BIT...HIGHS SAT MAY BE IN THE 12-14Z RANGE THEN DROP A FEW DEGREES FOR THE REST OF THE DAY. WIND CHILLS MUCH OF SAT LOOKING TO BE IN THE -15 TO -25 RANGE AND APPEARS A WIND CHILL ADVISORY WILL BE NEEDED FOR PORTIONS OF THE FCST AREA AT LEAST SAT MORNING. SAT NIGHT SHAPING UP TO BE ONE OF THE COLDEST NIGHTS OF THE 2014-2015 WINTER WITH THE CENTER OF THE HIGH OVER WI/EASTERN IA AT 12Z SUN. LIGHT/CALM WINDS...MOSTLY CLEAR SKIES AND SNOW DEPTHS MOSTLY 3 TO 8 INCHES...MOST LOCATIONS LOOKING AT LOWS OF -10F TO -20F...PERHAPS AS LOW AS -30F IN THE SHELTERED LOW LAYING LOCATIONS. WINDS WILL BE QUITE LIGHT SAT NIGHT INTO SUN MORNING...BUT WITH TEMPS THAT COLD WILL LIKELY NEED A WIND CHILL ADVISORY FOR MOST IF NOT ALL OF THE FCST AREA FOR LATER SAT NIGHT/SUN MORNING. SLOW MODERATION STARTS SUN/SUN NIGHT AS THE CENTER OF THE HIGH DRIFTS EAST OF THE AREA AND LOW LEVEL WARM ADVECTION RETURNS. TEMPS SUN/SUN NIGHT STILL AROUND 20F BELOW NORMAL THOUGH. HIGHER LEVEL MOISTURE/ CLOUDS INCREASE THRU THE DAY SUNDAY WITH THE 925-700MB MOISTURE PROGGED SPREAD WEST TO EAST ACROSS THE FCST AREA LATER SUN AFTERNOON/SUN NIGHT. SMALL -SN CHANCE IN THE WEST END OF THE FCST AREA SUN AFTERNOON AND A SMALL CHANCE ACROSS MUCH OF THE FCST AREA SUN NIGHT REASONABLE FOR NOW. TRENDED TOWARD COLDER OF GUIDANCE LOWS SAT NIGHT...OTHERWISE STAYED NEAR THE MODEL/ENSEMBLE CONSENSUS FOR HIGHS/LOWS SAT/SUN/SUN NIGHT. FOR MONDAY THRU THURSDAY...DAYS 4 TO 7... MAIN FCST CONCERNS THIS PERIOD...SMALL -SN CHANCES CENTERED ON MON AND AGAIN THU...BELOW NORMAL TEMPERATURES THRU THE PERIOD. MEDIUM RANGE MODEL RUNS OF 12.00Z/12.12Z IN GOOD AGREEMENT FOR ANOTHER STRONGER SHORTWAVE TROUGH TO BE DROPPING INTO THE NORTHERN PLAINS MON...THEN MOVING INTO/ACROSS THE UPPER MIDWEST MON NIGHT THRU TUE NIGHT. DIFFERENCES BY 12Z WED ON HOW QUICKLY THE TROUGH AXIS WOULD MOVE EAST OF THE REGION...GFS FASTER...ECMWF SLOWER WITH EACH HOLDING CONSISTENCY TO ITS PREVIOUS RUNS. GENERAL AGREEMENT FOR THE TROUGHING TO SWING EAST OF THE AREA WED...WITH RISING HGTS WED NIGHT INTO THU AHEAD OF ANOTHER SHORTWAVE TROUGH PROGGED TO DROP SOUTH ACROSS MANITOBA. GIVEN THE GENERAL LARGER SCALE MODEL AGREEMENT NEXT WEEK...DAY 4-7 FCST CONFIDENCE IS AVERAGE THIS CYCLE. ROUND OF LOWER LEVEL WARM ADVECTION/ISENTROPIC LIFT TO SPREAD ACROSS THE AREA MON INTO MON NIGHT AS THE WEEKEND ARCTIC HIGH MOVES FURTHER EAST/SOUTH. SFC/LOWER LEVEL TROUGH WITH THE NEXT MID LEVEL SHORTWAVE ENERGY TO PUSH ACROSS THE REGION AS WELL MON/MON NIGHT. SMALL -SN CHANCES MON/MON NIGHT PER THE MODEL CONSENSUS REASONABLE FOR NOW UNTIL THE AVAILABLE MOISTURE DETAILS COME INTO BETTER FOCUS. PASSING SFC TROUGH USHERS ANOTHER CAN/ARCTIC HIGH INTO THE UPPER MIDWEST FOR LATER MON NIGHT INTO WED. AFTER A BIT OF A WARMUP MON...925MB TEMPS IN THE -8C TO -12C RANGE AT 00Z TUE...925MB TEMPS PROGGED BACK IN THE -19 TO -23C RANGE BY 12Z WED. ON WED..MORE PROGRESSIVE GFS SPREADS IN LOW LEVEL WARM ADVECTION WHILE ECMWF CONTINUES WITH COLD ADVECTION. OVERALL DIFFERENCE OF 925MB TEMPS ON WED ONLY 2C TO 4C...BUT NOT A LOT OF CONFIDENCE ON HIGHS GIVEN NORTHWEST VS. SOUTHWEST LOW LEVEL FLOW AND CLOUD DIFFERENCES BETWEEN GFS/ECMWF. MORE CONSISTENT SIGNAL FOR A STRONGER ROUND OF LOW LEVEL WARM ADVECTION/LIFT AHEAD OF THE NEXT TROUGH TO SPREAD ACROSS THE REGION THU. EVEN WITH THIS...NAEFS ENSEMBLE AVERAGE HAS LOW LEVEL TEMPS 1-2 STANDARD DEVIATIONS BELOW NORMAL ON THU. MODEL/ENSEMBLE CONSENSUS OF HIGHS/LOWS FOR MON-THU APPEARS WELL TRENDED FOR NOW...REMAINING SOME 5 TO 15 DEGREES BELOW NORMAL NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1150 PM CST THU FEB 12 2015 THE MAIN FOCUS CONTINUES TO BE ON THE CHANCES FOR SNOW AND SUB-VFR FLIGHT CONDITIONS AS IT MOVES THROUGH. IT STILL LOOKS LIKE THE POTENTIAL FOR LIGHT SNOW WILL BE TOWARD DAYBREAK. CURRENTLY...THIS SNOW IS DEVELOPING ACROSS NORTHERN MINNESOTA WITH CONDITIONS MAINLY MVFR FROM LOW CEILINGS. A FEW SPOTS HAVE VISIBILITY DOWN AROUND 2SM...BUT IT IS PRETTY BRIEF. WAS NOT CONFIDENT ENOUGH TO DROP DOWN CONDITIONS TO IFR YET...BUT A BRIEF PERIOD OF IT WILL BE POSSIBLE AS THIS SNOW COMES THROUGH FRIDAY MORNING. CONDITIONS ARE EXPECTED TO IMPROVE GOING INTO THE AFTERNOON/EVENING AS WINDS COME AROUND TO THE WEST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...RRS LONG TERM....RRS AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1028 PM CST THU FEB 12 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SYNOPSIS...ISSUED AT 239 PM CST THU FEB 12 2015 WATER VAPOR LOOP AND RUC ANALYSIS REVEALS AMPLIFIED PATTERN FEATURING WEST COAST RIDGE AND BROAD UPSTREAM TROF ACROSS MUCH OF NORTH AMERICA. MODELS INDICATE THIS PATTERN WILL STAY IN PLACE OVER MUCH OF NEXT WEEK ALLOWING FOR PERIODIC SURGES OF ARCTIC AIR INTO THE REGION RESULTING IN BLO NORMAL TEMPS. MODELS ADVERTISE ONLY PERIODIC LIGHT PCPN WITH A FEW CLIPPER SHORTWAVES TRAVERSING AREA. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 239 PM CST THU FEB 12 2015 MINS TEMP FCST TONIGHT COULD BE TRICKY AS WINDS WILL DIE OFF WITH SFC RDG MOVING ACROSS THE AREA. ALSO WAA MID-HIGH CLOUDS WILL BE SPREADING INTO THE AREA AHEAD OF SHORTWAVE AND ASSOC SFC LOW DIVING DOWN FM CENTRAL CANADA. THESE CLOUDS DEPENDING ON HOW THICK THEY ARE MAY TEMPER RADIATIONAL COOLING UNDER LIGHT WIND REGIME. GIVEN UNCERTAINTY WITH CLOUD THICKNESS DECIDED TO USED A BLEND OF COLDER BASE REG GEM/ECMWF TEMPS AND MOS GUIDE TEMPS WHICH WAS CLOSE TO PREV FCST AND IN MEDIUM RANGE OF TEMP GUIDANCE. BACKED OFF SLIGHTLY ON POPS FOR FRI AS MODELS INDICATE BEST MOISTURE AND ISENTROPIC ASCENT STAYING GENERALLY NORTH OF WI CLOSER TO TRACK OF SHORTWAVE AND ASSOC SFC LOW. HAVE POPS RANGING FROM HIGH CHC (AROUND 50 PCT) NORTH TO LOWER CHC 30-40 POPS FOR SOUTHERN PORTIONS OF CWA. WAA WL HELP TEMPS RECOVER TO AROUND 20F...BUT MAX TEMPS PROBABLY WON/T OCCUR UNTIL LATE IN THE DAY SO ADJUSTED DIURNAL CURVE ACCORDINGLY. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 233 PM CST THU FEB 12 2015 N-NW WINDS WILL BE ON THE INCREASE LATE FRIDAY NIGHT INTO SATURDAY THANKS TO THE INCREASING PRESSURE GRADIENT BETWEEN THE EXITING SFC LOW SHIFTING FROM JUST E OF LAKE SUPERIOR AT 00Z SATURDAY TO THE LOWER GREAT LAKES SATURDAY AFTERNOON...AND THE COLD ARCTIC HIGH SINKING ACROSS S CENTRAL CANADA AND INTO THE N PLAINS. WHILE THE COLDEST AIR WILL REMAIN N-NE OF WI...STILL EXPECT 850MB TEMPS TO BOTTOM OUT AROUND -27 TO -30C SATURDAY AFTERNOON. AS A RESULT...STEADY TO FALLING TEMPERATRUES WILL BE COMMON SATURDAY AS THIS COLDER AIR RUSHES IN. HIGHS SATURDAY MAY ONLY ONLY TOP OUT IN THE -3 TO 7F RANGE /COLDEST NE/. KEPT THE POTENTIAL FOR BLOWING SNOW WHERE POPS WERE OVER 14 PERCENT...AND WIND GUSTS WERE OVER 20KTS. THE BEST CHANCE OF SNOW WILL BE OVER THE N ANE E TIER COUNTIES AS LAKE EFFECT ON STRONG WINDS BLOW WELL INLAND AND INTO N WI. UNDER A CLEARING SKY SATURDAY NIGHT...AND WITH WINDS OF 5-10KTS OUT OF THE N-NNW...WIND CHILL READINGS OF 25 TO 30 BELOW ZERO WILL BE POSSIBLE. LOOK FOR LATER UPDATES AND FORECASTS ON THIS ARCTIC AIRMASS AND LOW WIND CHILLS. GENEARALLY FOLLOWED A MODEL BLEND FOR MUCH OF THIS PERIOD. NO SIGNIFICANT STORMS ANTICIPATED...BUT WITH COLD WEATHER CONTINUING. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1022 PM CST THU FEB 12 2015 EXPECT VFR CONDITIONS AT ALL TAF SITES OVERNIGHT...WITH INCREASING MID-LEVEL CLOUDS ANTICIPATED. A CLIPPER LOW PRESSURE WILL TRACK NORTH OF THE REGION ON FRIDAY...AND BRING SOME LIGHT SNOW AND ASSOCIATED MVFR CONDITIONS DURING THE DAY. A STRONG COLD FRONT WILL MOVE THROUGH THE FORECAST AREA DURING THE LATE AFT/EVG... AND SHOULD BRING SCT SNOW SHOWERS/FLURRIES...MVFR CIGS AND INCREASING NW WINDS. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS.......VOSS SHORT TERM.....VOSS LONG TERM......KF AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
237 AM PST FRI FEB 13 2015 .SYNOPSIS... HIGH PRESSURE OVER CALIFORNIA WILL KEEP DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES ACROSS THE REGION THROUGH NEXT WEEK. PATCHY FOG WILL ALSO BE POSSIBLE IN THE SAN JOAQUIN VALLEY EACH NIGHT INTO THE MORNING HOURS. && .DISCUSSION...PATCHY DENSE FOG IS BEGINNING TO FORM ALONG AND WEST OF HIGHWAY 99 IN THE SAN JOAQUIN VALLEY. CURRENTLY MADERA AND HANFORD ARE REPORTING VISIBILITY AT OR LESS THAN ONE HALF MILE. THE HRRR INDICATES VISIBILITY CONTINUING TO DETERIORATE THROUGH 16Z BEFORE IMPROVING SIGNIFICANTLY AROUND 18Z. UPPER LEVEL HIGH PRESSURE WILL REMAIN DOMINANT OVER REGION TODAY INTO THE FIRST PART OF THE WEEKEND RESULTING IN ABOVE NORMAL DAYTIME HIGH TEMPERATURES...DRY CONDITIONS...AND PATCHY LATE NIGHT AND EARLY MORNING FOG. TEMPERATURES THIS AFTERNOON WILL BE SIMILAR TO THOSE OBSERVED YESTERDAY...WITH VALLEY...DESERT...AND FOOTHILL LOCATIONS IN THE 70S. THESE TEMPERATURES ARE BETWEEN 10 AND 15 DEGREES ABOVE NORMAL FOR THE MIDDLE OF FEBRUARY. THE ENSEMBLE MEAN FORECASTS INDICATE ZONAL FLOW WILL PREVAIL OVER THE REGION DURING THE SECOND HALF OF THE WEEKEND WITH UPPER LEVEL NORTHWEST FLOW THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN A SUBTLE COOLING TREND ACROSS THE AREA. BY TUESDAY...VALLEY TEMPERATURES WILL RANGE FROM THE UPPER 60S TO MID 70S...STILL WELL ABOVE NORMAL. BY THE THURSDAY/FRIDAY TIME FRAME OF NEXT WEEK...THE ENSEMBLE MEAN FORECAST INDICATES THAT UPPER LEVEL HIGH PRESSURE WILL SHIFT SLIGHTLY EAST OVER THE REGION ONCE AGAIN. THE CLIMATE PREDICTION CENTERS 6 TO 10 DAY OUTLOOK (VALID FROM FEBRUARY 18TH THROUGH 22ND) CALLS FOR A HIGH PROBABILITY OF BELOW NORMAL PRECIPITATION FOR THE ENTIRE REGION AND A HIGH PROBABILITY OF ABOVE NORMAL TEMPERATURES. && .AVIATION... IN THE SAN JOAQUIN VALLEY...IFR CONDITIONS WITH AREAS OF LIFR/VLIFR CEILINGS AND VISIBILITIES UNTIL 18Z FRIDAY. OTHERWISE...MVFR VISIBILITIES WILL PREVAIL IN HAZE DURING THE NEXT 24 HOURS WITH AREAS OF IFR/LIFR DEVELOPING AGAIN AFTER 08Z SATURDAY. VFR CONDITIONS CAN BE EXPECTED ELSEWHERE ACROSS THE CENTRAL CALIFORNIA INTERIOR DURING THE NEXT 24 HOURS. && .AIR QUALITY ISSUES... ON FRIDAY FEBRUARY 13 2015... UNHEALTHY FOR SENSITIVE GROUPS IN KERN COUNTY. FIREPLACE/WOOD STOVE BURNING STATUS IS: NO BURNING UNLESS REGISTERED IN FRESNO... KERN... KINGS... MADERA... MERCED AND TULARE COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .CERTAINTY... THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH. THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS HIGH. THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD. CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL INFORMATION AND/OR TO PROVIDE FEEDBACK. && .CLIMATE... RECORDS SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR KFAT 02-13 79:1921 43:1903 56:1987 24:1949 KFAT 02-14 79:1924 46:1903 55:1986 25:1949 KFAT 02-15 79:1977 49:1990 58:1902 24:1990 KBFL 02-13 83:1924 49:1949 55:1986 25:1908 KBFL 02-14 78:1991 47:1990 55:1986 21:1903 KBFL 02-15 84:1977 50:1911 56:1982 21:1903 && .HNX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING CAZ090>092. && $$ PUBLIC...RILEY AVN/FW...BEAN SYNOPSIS...RILEY WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
407 AM CST FRI FEB 13 2015 .SHORT TERM /TODAY/... ISSUED AT 345 AM CST FRI FEB 13 2015 GOOD WAA ADVECTION IS UNDERWAY...BUT MOISTURE IS LACKING AND THE FORCING IS RELATIVELY WEAK...THOUS THE SNOW BAND IS NOT PRODUCING MUCH. MEASURABLE SNOW FROM HERE ON OUT IS PRETTY MUCH OUT OF THE QUESTION AND WILL LIKELY TAKE OUT GRADUALLY OUT OF THE CWA AS FLURRIES TEMPS TODAY WILL MODERATE WITH THE SOUTHWEST HALF OF THE CWA MAKING IT JUST ABOVE FREEZING. SOUTH TO SOUTHWEST WINDS ARE FAVORABLE...BUT NOT STRONG ENOUGH TO REALLY MIX DOWN THE WARMER AIR. .LONG TERM /TONIGHT THROUGH THURSDAY/... ISSUED AT 345 AM CST FRI FEB 13 2015 THE LONG TERM IS INTERESTING. IN GENERAL THE PATTERN CHANGES LITTLE WITH A VERY AMPLIFIED UPPER RIDGE ACROSS THE WEST AND A TROUGH OVER THE GREAT LAKES AND THE EAST. THE UPPER MIDWEST GET CAUGHT IN THE MIDDLE WITH A PARADE OF SHORT WAVES BUT MOISTURE ISNT GREAT AND FORCING IS RATHER HIT OR MISS. WHAT IS EVIDENT IS THAT THE PATTERN WE ARE IN WILL BE COLD. AFTER TODAY WE ARE NOT GOING TO SEE TEMPS MUCH ABOVE FREEZING FOR A WHILE. TONIGHT INTO SATURDAY A TROUGH SWEEPS OUT OF ONTARIO ACROSS EASTERN MN AND WISCONSIN. FURTHER WEST A SUBTLE WAVE DRIFTS ACROSS THE REGION AHEAD OF THE TROUGH. THERE IS THE POSSIBILITY OF A BRIEF SHOT OF LIGHT SNOW ACROSS THE WEST SATURDAY NIGHT AND AREA WIDE SUNDAY WITH THE TROUGH PASSAGE. MOST LOCATIONS WEST WILL SEE AN INCH TO AN INCH AND A HALF WHILE LOCATIONS EAST WILL SEE JUST SLIGHTLY LESS. HOWEVER AS THE TROUGH COMES DOWN AND BRINGS DOWN A SHOT OF VERY COLD AIR...WINDS ACROSS NORTHERN AND EASTERN IOWA WILL CRANK UP FOR SATURDAY. WINDS WILL GENERALLY BE 15 TO 25 MPH WITH 20 TO 30 MPH WINDS AND HIGHER GUSTS ACROSS THE NORTH AND EAST. SATURDAY NIGHT LOOKS VERY COLD. WINDS WILL BE DIMINISHING BUT WIND CHILLS WILL APPROACH OR EXCEED WIND CHILL ADVISORY CRITERIA THOUGH IT MAY NOT LAST LONG OR BE OVER A WIDESPREAD AREA. THIS WILL NEED TO BE MONITORED. SUNDAY AND SUNDAY NIGHT ANOTHER WAVE PASSES OVER IOWA BRINGING ANOTHER SHOT FOR LIGHT SNOW. THE MODELS ARE HAVING A TOUGH TIME RESOLVING THIS THOUGH AND RIGHT NOW CANNOT AGREE ON WHETHER IT WILL BE LITTLE MORE THAN FLURRIES OR IF LIGHT AMOUNTS ARE MORE LIKELY. WE GET INTO SOME VERY WEAK WARM ADVECTION LATE SUNDAY AND MONDAY WHERE THE SOUTHWEST MAY GET INTO THE LOWER 30S. THE REST OF THE STATE WILL STILL BE IN THE 20S THOUGH. ANOTHER SHORTWAVE PASSES BY MONDAY INTO TUESDAY AND APPEARS DRY BUT WILL USHER IN ANOTHER SHOT OF COLD AIR SO ITS BACK TO TEMPS IN THE SINGLE DIGITS AND TEENS WITH LOWS BELOW ZERO NORTHEAST TO THE TEENS SOUTHWEST. THE PATTERN REPEATS THROUGH THE REST OF THE WEEK WITH SLIGHTLY WARMER TEMPS AGAIN THURSDAY INTO FRIDAY. THE WARM UP ON FRIDAY COULD BE SIGNIFICANT BUT WILL BE SHORT LIVED...AND IF THE EURO IS RIGHT...WILL BE SHORT LIVED. && .AVIATION...13/06Z ISSUED AT 1054 PM CST THU FEB 12 2015 LIGHT SNOW MAKING LITTLE EAST PROGRESS WITH FORCING AND LIFT CONCENTRATED WEST OF I35 AS LACK OF SATURATION EAST OF I35 CONTINUES. HRRR SHOWS DRAMATIC WEAKENING OF BAND...SO ALONG WITH CURRENT TRENDS HAVE CUT BACK ON COVERAGE AND LIMITED VSBY REDUCTIONS AND CIG LOWERING THROUGH 12Z. SOME BKN MID LEVEL CLOUDS REMAIN THROUGH DAY PRIOR TO ARRIVAL OF ARCTIC BOUNDARY AND POSSIBLE -SN AGAIN TOWARD END OF PERIOD AS FRONT CROSSES THE REGION BY 14/06Z. STRONG NW WINDS TO DEVELOP LATE IN THE PERIOD MAINLY AFT 14/03Z NORTH SECTIONS. /REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MS LONG TERM...FAB AVIATION...REV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
939 AM CST FRI FEB 13 2015 .UPDATE... ISSUED AT 939 AM CST FRI FEB 13 2015 INCREASED THE SNOW CHANCES FOR THE REST OF THE MORNING INTO THE AFTERNOON ACROSS THE NORTHERN SECTIONS OF THE AREA. PERSISTENT LIGHT SNOW HAS BEEN FALLING AHEAD OF THE APPROACHING COLD FRONT AND BOTH THE 13.12Z NAM AND 13.14Z RAP SHOW A SHORT WAVE TROUGH WILL PASS THROUGH NORTHERN WISCONSIN AS THE COLD FRONT COMES THROUGH. THIS WAVE LOOKS TO BE STRONG ENOUGH TO PRODUCE A PERIOD OF MODERATE TO STRONG PV ADVECTION IN THE 500-300 MB LAYER ALONG WITH WEAK TO MODERATE QG CONVERGENCE IN THE 1000-500 MB LAYER. IN THE WARM SECTOR AHEAD OF THE COLD FRONT THERE SHOULD ALSO BE BETWEEN 2 AND 4 UBAR/S OF UP GLIDE ON THE 285K SURFACE. SNOWFALL AMOUNTS SHOULD REMAIN LIGHT WITH ACCUMULATIONS OF LESS THAN AN INCH FROM THIS ACTIVITY. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 235 AM CST FRI FEB 13 2015 UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST OUT OF CANADA TO ACROSS THE GREAT LAKES SAT. SFC FRONT/LOW WILL DRIVE AHEAD OF THE TROUGH...SLIDING ACROSS THE REGION TODAY. WARM AIR ADVECTION IN THE 850-700 MB LAYER AHEAD OF THE SFC BOUNDARY...ALONG WITH UPGLIDE ON THE 280-295 K SFCS. LATEST FOG/STRATUS SATELLITE IMAGERY POINTS TO A LARGE EXPANSE OF CLOUDS TRACKING SOUTHEAST ACROSS MN...ASSOCIATED WITH THE LOW LEVEL THERMODYNAMICS-SFC FRONT. SOME LIGHT SNOW ACROSS NORTHERN PORTIONS OF MN. BUFKIT SOUNDINGS VIA THE RAP/NAM/GFS SUGGEST MAINLY NEAR SFC-MID LEVEL SATURATION. PROFILES ARE SOMEWHAT MESSY IN THAT THE MOISTURE PROFILE IS NOT WELL DEFINED. SHOULD BE COLD ENOUGH FOR ICE...ALTHOUGH COLDEST ICE BEARING LAYER LOOKS NEAR SFC RATHER THAN A LOFT. OVERALL...NOT EXPECTING MUCH FOR ACCUMULATIONS AND BEST CHANCES WILL BE THIS MORNING - HIGHER IN THE I-94 CORRIDOR NORTHEAST. WHAT THIS SHORTWAVE LACKS IN PCPN IT WILL MAKE UP FOR WITH STRONG WINDS AND BITTER COLD. SIGNIFICANT TIGHTENING IN THE SFC PRESSURE GRADIENT TONIGHT INTO SATURDAY AS THE UPPER LEVEL TROUGH DROPS IN. STRONG COLD AIR ADVECTION AND SINKING AIR VIA QG DIVERGENCE MAXED BETWEEN 12-18Z SAT. SFC PRESSURE GRADIENT MAGNITUDES CLIMB ABOVE 40 KTS FOR THE EASTERN 1/2 OF WI SAT...WITH BUFKIT SOUNDINGS AT RST/LSE MIXING DOWN LOW 30 KTS. WINDS WILL BE ON THE INCREASE LATER THIS AFTERNOON...BUT SHOULD START TO RAMP UP OVERNIGHT...PERSISTING INTO SATURDAY AFTERNOON. COLD AIR SURGES IN TONIGHT...WITH LOW 20S BELOW ZERO AT 925 MB SAT AFTERNOON THROUGH SUNDAY. SUNDAY LOOKS TO BE THE COLDEST MORNING AS HIGH PRESSURE STARTS TO APPROACH FROM THE NORTHERN PLAINS. RADIATIONAL COOLING...WITH A LIGHTER WIND FIELD AND MOSTLY CLEAR SKIES...WILL SUPPORT LOWS IN THE TEENS TO NEAR 20 BELOW ZERO. THE COMBINATION OF THE STRONG WINDS AND TUMBLING TEMPS MAKE WIND CHILL ADVISORIES LIKELY FOR A BULK OF THE REGION LATE TONIGHT THROUGH SAT MORNING. DESPITE MUCH LIGHTER WINDS FOR SAT NIGHT/SUN MORNING...ANOTHER ADVISORY MAY BE NEEDED AS JUST A SLIGHT STIR OF 5 TO 10 KTS COULD DROP WIND CHILLS INTO THE MID -20S. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 235 AM CST FRI FEB 13 2015 EXTENDED MODELS IN GOOD AGREEMENT WITH KEEPING THE REGION UNDER NORTHWEST FLOW FOR MUCH OF NEXT WEEK. ECMWF/GFS/GEM ALL POINT TO A FAIRLY ACTIVE FLOW WITH BITS OF ENERGY SPINNING THROUGH THE FLOW...BUT NOTHING OVERLY DISTINCT AT THIS TIME...OR OF APPRECIABLE STRENGTH. LIKELY SEE SOME LIGHT SNOW OR FLURRIES FROM TIME TO TIME...BUT AMOUNTS LOOK MINIMAL. ONE SUCH DAY LOOKS LIKE SUNDAY NIGHT INTO MONDAY. AN UPPER LEVEL SHORTWAVE IS SLATED TO SLIDE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...WITH SOME MOSTLY MID-UPPER LEVEL QG CONVERGENCE WITH IT. 850-700MB WARM AIR ADVECTION LEADS THE SHORTWAVE ACROSS THE REGION. QUITE A LOT OF DRY/COLD AIR FOR THIS SYSTEM TO BATTLE AS IT MOVES IN THOUGH...AND MUCH OF ITS FORCING WILL HAVE TO GO INTO SATURATION. PROBABLY HAS ENOUGH LIFT AND EVENTUAL SATURATION FOR SOME LIGHT SNOW- FLURRIES SUNDAY NIGHT THROUGH MONDAY. AMOUNTS SHOULD BE HELD IN CHECK THOUGH...AND LOOK MINIMAL AT THIS TIME. WILL LET THE CONSENSUS SOLUTION SORT OUT SNOW CHANCES BEYOND THIS PERIOD. MORE SIGNIFICANTLY WILL BE THE ABUNDANCE OF COLD AIR THE NORTHWEST FLOW WILL BRING. CPC 6-10 AND 8-14 DAY OUTLOOKS KEEP THE REGION IN HIGH PROBABILITIES FOR BELOW NORMALS TEMPERATURES - IN EXCESS OF 80 PERCENT. NAEFS 850 MB TEMP ANOMALIES ARE GENERALLY -1 TO -3 THROUGH THE PERIOD. ITS GOING TO STAY COLD THROUGH THE NEW WORK WEEK. SOME INDICATIONS THAT THE FOLLOWING WEEKEND TEMPS COULD MODERATE A BIT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 542 AM CST FRI FEB 13 2015 A WARM FRONT PUSHING THROUGH THE AREA TODAY WILL PRODUCE POCKETS OF LIGHT SNOW OR FLURRIES MAINLY THIS MORNING WITH CIGS TEETERING BETWEEN VFR AND HIGHER-END MVFR. AN ARCTIC COLD FRONT WILL PLUNGE THROUGH THE AREA TONIGHT WITH FROPA EXPECTED AT KRST AROUND 03Z AND AT KLSE AROUND 05Z. THERE WILL LIKELY BE A FEW FLURRIES AGAIN WITH THE COLD FRONTAL PASSAGE MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER WITH CEILINGS RIGHT ON THE VFR/MVFR CUSP. PLAN ON GUSTY NORTHWEST TONIGHT IN THE 15KT TO 30KT RANGE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...04 SHORT TERM...RIECK LONG TERM....RIECK AVIATION...DAS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
220 PM MST FRI FEB 13 2015 .SHORT TERM...VALID FOR SAT AND SUN... ...AFTER A VERY PLEASANT AND WARM DAY TODAY...THE WEATHER WILL GET MORE INTERESTING BY THE END OF THE HOLIDAY WEEKEND... DAYTIME HIGH TEMPERATURES THIS AFTERNOON ARE APPROACHING NEAR RECORD VALUES DUE TO STRONG MIXING IN THE LOWER PORTIONS OF THE ATMOSPHERE. 1 PM TEMPERATURES ACROSS THE REGION WERE GENERALLY IN THE UPPER 50S AND LOWER 60S AND ON THE RISE DUE TO FAIRLY PERSISTENT SURFACE WINDS. BY TONIGHT...MODELS ARE IN GOOD AGREEMENT IN BRINGING A BACK DOOR COLD FRONT WITH THE AIR BEHIND IT ORIGINATING FROM SOUTHERN SASKATCHEWAN AND MANITOBA. THERE IS NOT ANY DOUBT IT WILL GET COOLER IN THE OUR FAR EASTERN ZONES...BUT THERE IS UNCERTAINTY IN HOW FAR WEST THE COLD AIR WILL ACTUALLY GET. THERE IS A CHANCE SOME LOCATIONS OUT EAST...BAKER...EKALAKA...COULD SEE HIGHS HOVERING AROUND 30 DEGREES TOMORROW...WHILE OTHER LOCATIONS SUCH AS BILLINGS SEE HIGHS WELL INTO THE 50S. WINDS WILL SHIFT EASTERLY WITH THE ONSET OF THIS BAROCLINIC ZONE...AND BRING SOME CLOUD COVER WITH IT. HRRR BUFKIT SOUNDING ANALYSIS SUGGESTS THE EASTERLY FLOW WILL BRING DIMINISHED VISIBILITIES TO KMLS AND KBHK BY SATURDAY MORNING. HOWEVER...THE COLDEST AIR WILL REMAIN WELL TO THE NORTH AND EAST OF THE BILLINGS CWA. FOR SATURDAY NIGHT INTO SUNDAY...THINGS GET A LITTLE MORE INTERESTING AS THE AFOREMENTIONED LINGERING FRONT INTERACTS WITH AN UPPER LEVEL SHORTWAVE MOVING IN FROM THE NORTHWEST. THE MAIN IMPACT WILL NOW TURN TO SNOW ACCUMULATIONS IN THE BEARTOOTH FOOTHILLS. BUFKIT SOUNDING ANALYSIS HINTS AT A BRIEF PERIOD OF UPSLOPE FLOW ACCOMPANIED WITH A FAIRLY UNSTABLE AIR MASS BY TOMORROW AFTERNOON...WHICH COULD GENERATE SEVERAL INCHES OF SNOW FOR AREAS NEAR NYE AND RED LODGE. TAKING A LOOK AT THE CIPS ANALOGS FOR SIMILAR CASES...IT FURTHER BACKS THE THEORY THAT THE FOOTHILL LOCATIONS ARE THE PREFERRED AREA FOR POTENTIAL ACCUMULATING SNOW. EITHER WAY...DECIDED TO HOLD OFF ON ISSUANCE OF A WINTER WEATHER ADVISORY AT THIS FORECAST PACKAGE...AS AMOUNTS ARE STILL NOT SOLIDIFIED AT THIS TIME. WOULD GUESS ANYWHERE FROM 3-6 INCHES IS POSSIBLE WHEN ALL IS SAID AND DONE. SINGER .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... EXTENDED PERIOD BEGINS ON MONDAY WITH THE NOSE OF A STRONG UPPER LEVEL JET DIVING INTO NORTHERN IDAHO. DURING THE DAYS TO FOLLOW...THIS JET STREAK WILL SLIDE TO THE EAST AND ASSIST THE PROGRESSION OF A SERIES OF SHORTWAVES THROUGH THE REGION. THERE REMAINS THE POTENTIAL FOR SOME ACCUMULATING SNOW IN BOTH THE BIG HORN AND BEARTOOTH RANGES...AS THE ORIENTATION OF THE MAIN UPPER LEVEL FORCING FAVORS THOSE PARTICULAR AREAS THE MOST. AFTER A BRIEF COOLDOWN EARLY IN THE WEEK...TEMPERATURES WILL AGAIN BECOME SOMEWHAT MILD AFTER MONDAY. THE FORECAST REMAINS UNCERTAIN AFTER THAT...SO LEFT THE REMAINING FORECAST AS IS UNTIL MODELS COME INTO BETTER AGREEMENT. SINGER && .AVIATION... SOMEWHAT GUSTY WINDS WILL CONTINUE INTO THIS EVENING AT ALL TERMINALS. BY TONIGHT...HOWEVER...A COLD FRONT WILL MAKE ITS WAY FROM THE NORTHEAST INTO FAR EASTERN MONTANA. WINDS WILL SHIFT TO AN EASTERLY COMPONENT AT KBHK AND KMLS...BRINGING IN LOW LEVEL CLOUDS DURING THE OVERNIGHT HOURS. THEREFORE...MVFR CONDITIONS MAY COME INTO PLAY AT THAT TIME. SINGER && .PRELIMINARY POINT TEMP/POPS... SAT SUN MON TUE WED THU FRI ----------------------------------------------------------- BIL 035/059 034/046 027/036 018/037 024/043 028/049 031/046 01/E 25/W 54/J 32/J 11/B 11/B 22/W LVM 039/060 034/047 026/036 018/040 023/048 029/049 032/048 01/N 34/W 53/J 21/B 11/N 11/N 22/W HDN 030/056 029/046 024/035 013/034 018/041 023/049 026/045 01/E 24/W 44/J 32/J 22/J 11/B 22/W MLS 025/038 024/043 021/030 009/026 015/036 019/042 024/040 12/S 21/E 23/J 21/B 22/J 11/B 22/J 4BQ 027/043 027/045 023/033 013/028 017/039 020/047 026/043 12/O 21/E 24/J 31/B 22/J 11/B 22/W BHK 014/024 017/037 020/027 005/021 010/032 017/038 021/037 12/S 31/N 24/J 21/B 22/J 11/E 22/J SHR 031/056 029/045 023/032 013/031 016/040 020/047 025/043 01/B 33/W 55/J 42/J 22/J 11/B 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
528 PM EST FRI FEB 13 2015 .SYNOPSIS... A STRONG ARCTIC FRONT WILL SLICE ACROSS THE COMMONWEALTH FROM THE LATE SATURDAY MORNING THROUGH SATURDAY AFTERNOON...PRECEDED BY AREAS OF LIGHT SNOW AND A LINE OF INTENSE SNOW SQUALLS. WIDESPREAD LIGHT SNOW ACCUMULATIONS ARE EXPECTED FOR MOST...WHILE A FEW TO SEVERAL INCHES OF WIND BLOWN SNOW ARE POSSIBLE ACROSS THE HIGHER ELEVATIONS OF THE NORTHERN AND WESTERN MOUNTAINS...AND IN PARTICULAR THE LAUREL HIGHLANDS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MCLEAR SKIES AND LIGHT WINDS TO START THIS EVENING...AS SFC RIDGE DRIFTS ACROSS CENTRAL PA. HOWEVER...SATL LOOP SHOWS CLOUDS IN ADVANCE OF APPROACHING CLIPPER ABOUT TO ENTER WESTERN PA AT 22Z. IDEAL RADIATIONAL COOLING SHOULD RESULT IN MIN TEMPS THIS EVENING...THEN STEADY OR SLOWLY RISING READINGS AS CLOUDS ARRIVE BTWN 00Z-05Z FROM WEST TO EAST. CONSALL OUTPUT SUGGEST LOWS WILL RANGE FROM THE UPPER SINGLE DIGITS TO LTEENS OVER MOST OF THE AREA. HOWEVER...LATEST RAP OUTPUT SUGGESTS THE COLDER VALLEYS OF THE NORTH WILL DIP BLW ZERO FOR A TIME THIS EVENING...WITH SOME SINGLE DIGITS IN THE FROST POCKETS OF THE CENTRAL AND SOUTHERN COUNTIES. REGIONAL RADAR LOOP AT 22Z SHOWS LIGHT SNOW ACROSS MICHIGAN IN REGION OF WAA AHEAD OF CLIPPER. LATEST NR TERM MDL DATA SUGGESTS THIS LGT SNOW WILL OVERSPREAD THE N MTNS BTWN 03Z-06Z. LACK OF DEEP MOISTURE WILL LIMIT LGT ACCUMS TO MAINLY THE N MTNS...WHERE SOUTHERLY FLOW/OROGRAPHIC LIFT WILL PLAY A ROLE. BLEND OF MDL QPF SUPPORTS SNOW AMTS BY DAWN OF NEAR AN INCH ACROSS THE N MTNS...WITH LITTLE IF ANY ACCUM SOUTH OF I-80. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... A VIGOROUS UPPER TROUGH AND ASSOCIATED ARCTIC FRONT WILL DROP SOUTHEAST THROUGH THE REGION DURING THE DAY SATURDAY. BROAD UPPER DIFFLUENCE AHEAD OF THIS TROUGH AND A BRIEF PERIOD OF SWRLY FLOW AT THE SURFACE WILL MAINTAIN LIGHT SNOW/SNOW SHOWERS ACROSS WESTERN AND CENTRAL AREAS THROUGH THE MORNING HOURS. AN APPROX 75NM WIDE BAND OF STEEP MID-LEVEL LAPSE RATES /OR 7-8C PER KM/ OCCURS ALONG AND JUST IN ADVANCE OF THE ARCTIC FRONT SATURDAY. THIS WILL LEAD TO SCATTERED...BLINDING SNOW SQUALLS GIVEN THE STRONG 40-45 KT WINDS AT 850 MB SURROUNDING THE CFROPA. BTV SNOW SQUALL PARAMETER AND HI RES MESO MODELS ARE HITTING ON ALL CYLINDERS WITH THIS SQUALL EVENT...AND IT IS CLEAR THAT THE ARCTIC AIR WILL HAVE A LOUD ARRIVAL PUNCTUATED BY A LINE OF INTENSE SNOW SQUALLS WITH HAZARDOUS INTERSTATE TRAVEL CONDITIONS EXPECTED FROM WEST TO EAST SATURDAY AFTERNOON. FAVORABLE UPSLOPE LOCATIONS NEAR AND TO THE WEST OF RT 219 SEE A GENERAL 2-4 INCHES...WITH ANOTHER INCH OR SO POSSIBLE FROM THE LINE OF SQUALLS LEADING TO A GENERAL 3 TO 5 INCHES AND GARNERING THE ISSUANCE OF A WINTER WEATHER ADVISORY FOR SOMERSET CAMBRIA AND CLEARFIELD COUNTIES. FARTHER NORTH...SIMILAR 2-3 INCH AMOUNTS LIKELY ACROSS THE MTNS NE OF KIPT AS THE CENTER OF THE 700-500 MB LOW MOVES NEAR OR JUST SOUTH OF THE REGION LATE SAT NIGHT. WIND CHILL WATCH FOR SAT EVENING THROUGH SUNDAY MORNING FOR THE ENTIRE CWA REMAINS IN EFFECT. HIGH WIND WATCH FOR THE LOWER SUSQ RIVER VALLEY ALSO REMAINS IN EFFECT. HIGHS SATURDAY WILL NOSE INTO THE LOWER 20S LATE IN THE MORNING ACROSS THE NW MTNS AND LAURELS...AND INTO THE LOWER 30S ACROSS THE SE ZONES EARLY SATURDAY AFTERNOON - BEFORE THE ARCTIC FRONT SURGES SE ACROSS THE REGION. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH. NEXT STORM WILL BE EXITING THE REGION SAT NIGHT /AND WILL BE DEEPENING RAPIDLY AS IT IMPACTS THE NEW ENGLAND COAST/...WITH SNOW SHOWERS LINGERING MAINLY IN MY HIGHER TERRAIN INTO SUNDAY. SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF MY CWA EARLY SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHT ACCUMULATIONS OF UP TO A FEW INCHES IN FOR THAT LIKELIHOOD. BIGGER STORM WILL BE SURGE OF BRUTALLY COLD AIR IN ITS WAKE...BRINGING THE COLDEST AIR OF THE SEASON TO PA. THE COLDEST TEMPS /AND WIND CHILLS/ ARRIVE SAT NIGHT AND CONTINUE INTO SUNDAY...WITH COLDEST STRAIGHT- UP TEMP READINGS SUN NIGHT WHEN GEFS MEAN 850 MB TEMPS DROP TO -24 TO -28C ACROSS CENTRAL PENN. AFTERNOON HIGHS SUNDAY WILL REMAIN BELOW ZERO ACROSS THE NORTHERN MOUNTAINS AND LAUREL HIGHLANDS...AND MAINLY IN THE SINGLE DIGITS ABOVE ZERO ELSEWHERE. TO COMPLICATE MATTERS...STRONG NORTHWEST WIND GUSTS ANTICIPATED OVER 40 MPH SAT NIGHT AND EARLY SUNDAY WILL BRING ANOTHER ROUND OF DANGEROUS...AND EVEN COLDER WIND CHILLS OF 20 TO 30 BELOW ZERO. THOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE. RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING OFFSHORE ON TUESDAY. STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS CONTINUE TO LEND CREEDENCE TOWARD A MORE SUPPRESSED/FLATTER SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS. YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH PRESSURE COVERS THE EASTERN HALF OF THE CONUS. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... VFR PREVAILING THIS AFTERNOON...WITH HIGH PRESSURE OVER THE AIRSPACE. SFC WINDS WILL CONTINUE TO SUBSIDE AND GRADUALLY BACK TO THE WSW TONIGHT...AS LOW PRES TRACKS SE ACROSS THE UPPER GREAT LAKES. AN ACTIVE WINTER WX PERIOD IS SHAPING UP FOR THE WEEKEND WITH WIDESPREAD SNOW AND REDUCED VISBYS ON SAT FOLLOWED BY STRONG WINDS SAT NGT INTO EARLY SUNDAY. HIGH PRESSURE SHOULD RETURN VFR TO THE AREA EARLY NEXT WEEK. OUTLOOK... SAT...BCMG MVFR/IFR IN -SN. STG FROPA. WNW SFC WND GUSTS 25-35KTS. SUN...MVFR/IFR WEST IN -SHSN. VFR/MVFR CENTRAL AND EAST. WNW SFC WND GUSTS 25-35KTS...GRADUALLY DIMINISHING WEST TO EAST. MON...MVFR -SHSN EARLY WEST...BCMG VFR. VFR ELSEWHERE. TUE...CHC OF PM SNOW. WED...CHC OF AM SNOW. && .CTP WATCHES/WARNINGS/ADVISORIES... WIND CHILL WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING FOR PAZ012-018-019-025>028-034>037-041-042-045-046- 049>053-056>059-063>066. WINTER WEATHER ADVISORY FROM 7 AM SATURDAY TO MIDNIGHT EST SUNDAY NIGHT FOR PAZ017-024-033. WIND CHILL WATCH FROM SATURDAY EVENING THROUGH MONDAY MORNING FOR PAZ004>006-010-011-017-024-033. HIGH WIND WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR PAZ036-056>059-063>066. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DEVOIR/FITZGERALD SHORT TERM...DEVOIR/LAMBERT LONG TERM...RXR AVIATION...DEVOIR/STEINBUGL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1123 AM CST FRI FEB 13 2015 .UPDATE... ISSUED AT 939 AM CST FRI FEB 13 2015 INCREASED THE SNOW CHANCES FOR THE REST OF THE MORNING INTO THE AFTERNOON ACROSS THE NORTHERN SECTIONS OF THE AREA. PERSISTENT LIGHT SNOW HAS BEEN FALLING AHEAD OF THE APPROACHING COLD FRONT AND BOTH THE 13.12Z NAM AND 13.14Z RAP SHOW A SHORT WAVE TROUGH WILL PASS THROUGH NORTHERN WISCONSIN AS THE COLD FRONT COMES THROUGH. THIS WAVE LOOKS TO BE STRONG ENOUGH TO PRODUCE A PERIOD OF MODERATE TO STRONG PV ADVECTION IN THE 500-300 MB LAYER ALONG WITH WEAK TO MODERATE QG CONVERGENCE IN THE 1000-500 MB LAYER. IN THE WARM SECTOR AHEAD OF THE COLD FRONT THERE SHOULD ALSO BE BETWEEN 2 AND 4 UBAR/S OF UP GLIDE ON THE 285K SURFACE. SNOWFALL AMOUNTS SHOULD REMAIN LIGHT WITH ACCUMULATIONS OF LESS THAN AN INCH FROM THIS ACTIVITY. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 235 AM CST FRI FEB 13 2015 UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST OUT OF CANADA TO ACROSS THE GREAT LAKES SAT. SFC FRONT/LOW WILL DRIVE AHEAD OF THE TROUGH...SLIDING ACROSS THE REGION TODAY. WARM AIR ADVECTION IN THE 850-700 MB LAYER AHEAD OF THE SFC BOUNDARY...ALONG WITH UPGLIDE ON THE 280-295 K SFCS. LATEST FOG/STRATUS SATELLITE IMAGERY POINTS TO A LARGE EXPANSE OF CLOUDS TRACKING SOUTHEAST ACROSS MN...ASSOCIATED WITH THE LOW LEVEL THERMODYNAMICS-SFC FRONT. SOME LIGHT SNOW ACROSS NORTHERN PORTIONS OF MN. BUFKIT SOUNDINGS VIA THE RAP/NAM/GFS SUGGEST MAINLY NEAR SFC-MID LEVEL SATURATION. PROFILES ARE SOMEWHAT MESSY IN THAT THE MOISTURE PROFILE IS NOT WELL DEFINED. SHOULD BE COLD ENOUGH FOR ICE...ALTHOUGH COLDEST ICE BEARING LAYER LOOKS NEAR SFC RATHER THAN A LOFT. OVERALL...NOT EXPECTING MUCH FOR ACCUMULATIONS AND BEST CHANCES WILL BE THIS MORNING - HIGHER IN THE I-94 CORRIDOR NORTHEAST. WHAT THIS SHORTWAVE LACKS IN PCPN IT WILL MAKE UP FOR WITH STRONG WINDS AND BITTER COLD. SIGNIFICANT TIGHTENING IN THE SFC PRESSURE GRADIENT TONIGHT INTO SATURDAY AS THE UPPER LEVEL TROUGH DROPS IN. STRONG COLD AIR ADVECTION AND SINKING AIR VIA QG DIVERGENCE MAXED BETWEEN 12-18Z SAT. SFC PRESSURE GRADIENT MAGNITUDES CLIMB ABOVE 40 KTS FOR THE EASTERN 1/2 OF WI SAT...WITH BUFKIT SOUNDINGS AT RST/LSE MIXING DOWN LOW 30 KTS. WINDS WILL BE ON THE INCREASE LATER THIS AFTERNOON...BUT SHOULD START TO RAMP UP OVERNIGHT...PERSISTING INTO SATURDAY AFTERNOON. COLD AIR SURGES IN TONIGHT...WITH LOW 20S BELOW ZERO AT 925 MB SAT AFTERNOON THROUGH SUNDAY. SUNDAY LOOKS TO BE THE COLDEST MORNING AS HIGH PRESSURE STARTS TO APPROACH FROM THE NORTHERN PLAINS. RADIATIONAL COOLING...WITH A LIGHTER WIND FIELD AND MOSTLY CLEAR SKIES...WILL SUPPORT LOWS IN THE TEENS TO NEAR 20 BELOW ZERO. THE COMBINATION OF THE STRONG WINDS AND TUMBLING TEMPS MAKE WIND CHILL ADVISORIES LIKELY FOR A BULK OF THE REGION LATE TONIGHT THROUGH SAT MORNING. DESPITE MUCH LIGHTER WINDS FOR SAT NIGHT/SUN MORNING...ANOTHER ADVISORY MAY BE NEEDED AS JUST A SLIGHT STIR OF 5 TO 10 KTS COULD DROP WIND CHILLS INTO THE MID -20S. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 235 AM CST FRI FEB 13 2015 EXTENDED MODELS IN GOOD AGREEMENT WITH KEEPING THE REGION UNDER NORTHWEST FLOW FOR MUCH OF NEXT WEEK. ECMWF/GFS/GEM ALL POINT TO A FAIRLY ACTIVE FLOW WITH BITS OF ENERGY SPINNING THROUGH THE FLOW...BUT NOTHING OVERLY DISTINCT AT THIS TIME...OR OF APPRECIABLE STRENGTH. LIKELY SEE SOME LIGHT SNOW OR FLURRIES FROM TIME TO TIME...BUT AMOUNTS LOOK MINIMAL. ONE SUCH DAY LOOKS LIKE SUNDAY NIGHT INTO MONDAY. AN UPPER LEVEL SHORTWAVE IS SLATED TO SLIDE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...WITH SOME MOSTLY MID-UPPER LEVEL QG CONVERGENCE WITH IT. 850-700MB WARM AIR ADVECTION LEADS THE SHORTWAVE ACROSS THE REGION. QUITE A LOT OF DRY/COLD AIR FOR THIS SYSTEM TO BATTLE AS IT MOVES IN THOUGH...AND MUCH OF ITS FORCING WILL HAVE TO GO INTO SATURATION. PROBABLY HAS ENOUGH LIFT AND EVENTUAL SATURATION FOR SOME LIGHT SNOW- FLURRIES SUNDAY NIGHT THROUGH MONDAY. AMOUNTS SHOULD BE HELD IN CHECK THOUGH...AND LOOK MINIMAL AT THIS TIME. WILL LET THE CONSENSUS SOLUTION SORT OUT SNOW CHANCES BEYOND THIS PERIOD. MORE SIGNIFICANTLY WILL BE THE ABUNDANCE OF COLD AIR THE NORTHWEST FLOW WILL BRING. CPC 6-10 AND 8-14 DAY OUTLOOKS KEEP THE REGION IN HIGH PROBABILITIES FOR BELOW NORMALS TEMPERATURES - IN EXCESS OF 80 PERCENT. NAEFS 850 MB TEMP ANOMALIES ARE GENERALLY -1 TO -3 THROUGH THE PERIOD. ITS GOING TO STAY COLD THROUGH THE NEW WORK WEEK. SOME INDICATIONS THAT THE FOLLOWING WEEKEND TEMPS COULD MODERATE A BIT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1123 AM CST FRI FEB 13 2015 THE COLD FRONT CONTINUES TO ADVANCE SOUTHEAST AND STILL LOOKS TO BE ON TRACK TO PASS THROUGH BOTH TAF SITES LATE THIS AFTERNOON. ONCE THE FRONT PASSES THROUGH...THE WINDS WILL SWITCH AROUND TO THE NORTHWEST AND BECOME GUSTY. HOWEVER...THE STRONGEST WINDS WILL NOT OCCUR UNTIL LATE TONIGHT INTO SATURDAY MORNING WHEN THE 13.12Z NAM SHOWS THE STEEPEST LOW LEVEL LAPSE RATES WILL BE IN PLACE WITH WINDS OF 30 KNOTS AT THE TOP OF THE MIXED LAYER. THIS MIXED LAYER ALSO LOOKS LIKE IT WILL BE SATURATED FOR MVFR CEILINGS AND WITH SOME LIFT THROUGH THIS COLUMN FROM THE PASSAGE OF THE STRONG UPPER LEVEL SHORT WAVE AND LOW LEVEL CYCLONIC FLOW...WOULD EXPECT TO SEE SOME FLURRIES AT BOTH TAF SITES. IT LOOKS LIKE DRIER AIR WILL START TO MOVE IN SATURDAY MORNING TO ALLOW THE CLOUDS TO SCATTER OUT...BUT THE WINDS WILL REMAIN GUSTY THROUGH THE MORNING AS THE STEEP LAPSE RATES REMAIN IN PLACE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...04 SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04