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.
&&
$$
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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
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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