Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/20/14
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
938 PM MST FRI JAN 17 2014
.UPDATE...
&&
.SHORT TERM...WINDS HAVE DIMINISHED AT LOWER ELEVATIONS AND
TEMPERATURES HAVE BEEN BOBBING AROUND IN MANY AREAS AS THERE IS
STILL ENOUGH GRADIENT TO KEEP MOST PLACES FROM COMPLETELY
DECOUPLING. DIA DROPPED TO 29 DURING A BRIEF LULL BEFORE THE WEST
WIND PICKED UP AND IT WARMED UP AGAIN. WIND SHELTERED/LOW LYING
SPOTS LIKE GREELEY...LIMON AND KREMMLING ARE COLD AND SHOULD KEEP
DROPPING WHILE OTHER AREAS WILL KEEP A LITTLE WIND AND NOT FALL
MUCH FURTHER. MADE SOME MINOR ADJUSTMENTS TO TONIGHTS LOWS.
LOOKING LIKE A LITTLE MORE WIND NEAR THE EASTERN BORDER SATURDAY
AFTERNOON...NUDGED THE FORECAST TOWARD THE GFS MOS AND RUC WHICH
ARE A BIT WINDIER AND DRIER OUT THERE. WINDS ALONG THE FRONT RANGE
MAY BE TRICKY AS THE FLOW WILL BE BLOCKED BY THE MOUNTAINS...NOT
WESTERLY ENOUGH TO STAY WEST AND NOT NORTHERLY ENOUGH TO JUST BE
NORTH. THERE WILL PROBABLY BE SOME CHAOTIC EDDIES WITH GENERALLY
LIGHT SPEEDS...PERHAPS EVENTUALLY A SIMPLER NORTH TO NORTHEAST
TURNING AWAY FROM THE STRONG NNW WINDS ON THE PLAINS IN THE
AFTERNOON. SPEEDS WILL START TO DECREASE IN THE AFTERNOON AS THE
GRADIENT FALLS OFF. ADDED A LITTLE BLOWING DUST IN THE NORTHEAST
CORNER...IT SHOULD NOT BE AS BAD AS THURSDAY BUT THERE WILL LIKELY
BE SOME.
.AVIATION...VFR THROUGH SATURDAY. WEST WINDS AROUND 10 KNOTS
SHOULD TREND MORE SOUTHERLY AT KDEN/KAPA LATER THIS EVENING. WINDS
WILL LIKELY TURN NORTHWEST AND EVENTUALLY MORE NORTHERLY DURING
THE DAY SATURDAY. EXPECT SOME VARIABILITY IN DIRECTION ESPECIALLY
IN THE AFTERNOON AS SOME KIND OF EDDY WILL FORM OFF OF THE STRONG
NORTHWEST WINDS FURTHER EAST ON THE PLAINS. UPCOMING TAFS WILL
SHOW SOME EASTERLY COMPONENT LATER IN THE DAY. SPEEDS GENERALLY
EXPECTED TO BE LIGHT...THOUGH IF THE CIRCULATION GETS ORGANIZED
COULD BE UP TO 15 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 334 PM MST FRI JAN 17 2014/
SHORT TERM...MODERATE NORTHWEST FLOW ALOFT ACROSS REGION WITH
UPPER RIDGE MOVING INTO THE GREAT BASIN AND LARGE UPPER TROUGH
ACROSS MIDWEST. WINDS A BIT BREEZY IN AND NEAR FOOTHILLS AS WELL
AS ACROSS THE HIGHER RIDGES...WITH A FEW GUSTS AROUND 35 MPH IN
WIND PRONE AREAS. ACROSS PLAINS...WINDS MUCH LIGHTER WITH WEAK
ANTICYCLONE IN DENVER AREA. SOME HIGH LEVEL MOISTURE SPREADING
ACROSS AREA WITH NO SIGN OF WAVE CLOUD. RIDGE WILL CONTINUE TO
BUILD INTO THE GREAT BASIN THIS EVENING WITH NORTHWEST FLOW ALOFT
CONTINUING. WINDS WILL REMAIN A BIT GUSTY OVER THE HIGHER RIDGES
AND ALONG FOOTHILLS...WITH SOME GUSTS TO 40 MPH POSSIBLE. BREEZY
CONDITIONS WILL ALSO EXIST NEAR THE FOOTHILLS AS DRAINAGE WINDS
BECOME ENHANCED BY THE WESTERLIES. OTHERWISE...MAINLY CLEAR SKIES
WILL PREVAIL WITH LIGHT DRAINAGE WINDS. ON SATURDAY...NORTHWEST
FLOW ALOFT WILL CONTINUE AS UPPER RIDGE OVER GREAT BASIN BUILDS
TOWARD COLORADO AND LARGE UPPER TROUGH REMAINS OVER THE MIDWEST.
MODELS SHOW A WEAK MID LEVEL SHORTWAVE MOVING ACROSS THE NORTHERN
AND CENTRAL PLAINS STATES DURING THE DAY. AIRMASS WILL REMAIN DRY
AND SLIGHTLY WARMER. COMBINATION OF MIXING AND INCREASING SURFACE
GRADIENT WILL PRODUCE GUSTY WINDS ACROSS THE FAR NORTHEAST PLAINS
BETWEEN 15Z AND 21Z. COULD SEE SOME GUSTS APPROACHING 45 MPH.
FURTHER WEST...GRADIENT WILL BE WEAKER WITH LESS WIND. GUSTY WINDS
WILL STILL BE POSSIBLE OVER THE HIGHER RIDGES AND ALONG FOOTHILLS.
TEMPERATURE AND THICKNESS PROGS SUGGEST HIGHS WARMING ABOUT 2 TO 4
DEGREES F. FROM TODAY`S READINGS. THUS HIGHS TO WARM BACK INTO THE
MIDDLE 50S ACROSS THE PLAINS.
LONG TERM...A PERSISTENT UPPER RIDGE OVER THE WESTERN U.S. AND
WESTERN CANADA WILL LEAVE COLORADO DRY AND MILD THROUGH THE BULK
OF NEXT WEEK. EARLY IN THE PERIOD...THE WARMEST TEMPERATURES OF
THE WEEK MAY BE SUNDAY AFTERNOON. ON SUNDAY NIGHT...THERE ARE
INDICATIONS THAT A WEAK SURGE OF COOL AIR WILL DROP INTO THE STATE
SUNDAY NIGHT AND MONDAY MORNING. HIGH TEMPERATURES COULD BE UP TO
10 DEGREES COOLER ON MONDAY. THROUGH THE REST OF THE WEEK...THE
WEAK NORTHWEST FLOW ALOFT AND A SURFACE HIGH PRESSURE RIDGE OVER
THE NORTHERN PLAINS WILL KEEP FEEDING MODIFIED CANADIAN AIR INTO
THE STATE. THIS WILL TEND TO KEEP TEMPERATURES COOLER THAN IF
STRONGER NORTHWEST FLOW WERE IN PLACE. TEMPERATURES WILL STILL BE
WARMER THAN CLIMATOLOGY THROUGH THE PERIOD. THE AIRMASS WILL
REMAIN DRY...LEADING TO MOSTLY SUNNY SKIES EACH DAY.
AT THE END OF NEXT WEEK...THE GFS AND ECMWF ARE NOW SHOWING
AGREEMENT IN BRINGING SOME SORT OF SHORT WAVE ACROSS THE STATE. AS
BOTH MODELS INSIST ON PRODUCING SOME QPF AS THE SHORT WAVE MOVES
ACROSS...WILL INTRODUCE A SLIGHT CHANCE OF SNOW FOR THE MOUNTAIN
AREAS. THIS COULD HAPPEN ANYTIME FROM THURSDAY AFTERNOON THROUGH
FRIDAY...SO WILL COVER THE ENTIRE 30-36 HOUR PERIOD WITH THE
SLIGHT CHANCE POPS.
AVIATION...VFR TO CONTINUE WITH UNLIMITED CEILINGS. WEAK
ANTICYCLONE KEEPING LIGHT EASTERLY WINDS AT KDEN AND KAPA WITH
WESTERLY WINDS AT KBJC. DRAINAGE WINDS TO DEVELOP BY 03Z WITH
SOUTHERLY WINDS AT KDEN AND KAPA AND WESTERLY AT KBJC. SPEEDS
AROUND 8 KTS TO PREVAIL...WITH SOME GUSTS TO 20 KTS POSSIBLE AT
KBJC. WINDS TO WEAKEN BY 15Z SATURDAY AND SHIFT TO THE NORTHWEST.
SLIGHT CHANCE OF ANOTHER WEAK ANTICYCLONE DEVELOPING NORTH OF
DENVER BY 20Z WITH LIGHT NORTHEAST TO EAST WINDS AT KDEN AND KAPA.
FOR NOW WILL KEEP LIGHT NORTHWESTERLY WINDS AT THE AREA AIRPORTS
THROUGH 00Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1101 AM EST SAT JAN 18 2014
.SYNOPSIS...
DEVELOPING LOW PRESSURE WILL MOVE QUICKLY ACROSS SOUTHERN NEW
ENGLAND TODAY BUT WILL BRING A PERIOD OF ACCUMULATING SNOW TO
NORTHERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE. ELSEWHERE A MIX
OF SNOW AND RAIN WILL OCCUR WITH A MINOR SLUSHY ACCUMULATION
POSSIBLE. A WEAK TROUGH OF LOW PRESSURE ZIPS ACROSS THE AREA SUNDAY
BRINGING SCATTERED SNOW SHOWERS TO THE REGION. AN ARCTIC AIRMASS
WITH PUSH ACROSS THE REGION WITH PROGRESSIVELY COLDER CONDITIONS
AND BITTERLY COLD WIND CHILL VALUES BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1100 AM UPDATE...
VERY BUSY MORNING SO FAR AS SYSTEM CONTINUES TO EVOLVE. HAVE
PUT ISOLATED LIGHTNING INTO THE FORECAST ESP FOR AREAS EAST OF
I-95. A FEW RUMBLES HAVE OCCURRED INLAND...EVEN HERE AT THE WFO
AND LIGHTNING HAS BEEN PICKED UP OVER THE WATERS. BEST AREA FOR
ANY RUMBLE OF THUNDER CURRENTLY WITHIN THE HIGHER ECHOES ON THE
RADAR...NEAR SHARON AND NORTON MA.
OTHERWISE SHORTWAVE IS REALLY PUSHING INTO THE REGION PER LATEST
WV IMAGERY AND APPEARS THAT THE SYSTEM IS ALREADY STARTING TO
TURN MORE NEGATIVELY. PRECIP CONTINUES TO MOVE OVER THE SAME
REGION OF EASTERN MA AND WHERE TEMPS ARE BELOW 32...EXPECT SNOW.
BECAUSE OF THIS HAVE EXPANDED THE ADVISORY FOR EASTERN
HILLSBOROUGH. AM CONCERNED HOWEVER IF WE WILL HIT ADVISORY SNOW
OUT IN WESTERN MA...WHERE PRECIP IS THE LIGHTEST. LATEST HRRR HAS
BEEN LESS GENEROUS ON THE QPF AMOUNTS OUT THERE...AND OVERALL
RADAR ECHOES HAVE BEEN LIGHT. WILL NEED TO MONITOR TO MAKE
CHANGES. HAVE ADJUSTED THE SNOW GRIDS AS SNOW ACCUMS WONT OCCUR
UNLESS TEMPS ARE AT 32F OR 33F AS WE HAVE BEEN IN A WARM SPELL FOR
SOME TIME AND SNOW WILL STRUGGLE TO ACCUMULATE AT 34F. EVEN THE
LATEST SURFACE OBS ARE SHOWING SNOW FALLING ONLY WHEN TEMPS ARE
32F OF BELOW. 33F DEGREES OR HIGHER LIKE KBDL OR KBED AT ALL SNOW.
FINALLY THE OVERALL TREND IN THE FORECAST IS ON TRACK FOR THIS
MORNING.
PREVIOUS DISCUSSION...
*** ACCUMULATING SNOW TODAY ACROSS NORTHERN MA AND SOUTHERN NH ***
00Z MODELS HAVE TRENDED STRONGER WITH IMPRESSIVE SHORT WAVE/PV
ANOMALY OVER WESTERN PA EARLY THIS MORNING. AS FOR THE
DETERMINISTIC GUIDANCE...THE 00Z NAM IS ON THE WEAKER SIDE OF THE
GUID WHILE THE GFS IS MOST ROBUST AND THE ECMWF IN THE MIDDLE OF
THE PACK. THE EURO HAS SHOWN GOOD RUN TO RUN CONTINUITY...SO A
MODEL BLEND IS VERY CLOSE TO THE ECMWF SOLUTION AND IS WHAT THIS
FORECAST IS BASED ON.
WATER VAPOR IMAGERY BEGINNING TO SHOW SIGNS OF THIS MID LEVEL
TROUGH TRANSITIONING FROM A POSITIVE TO NEUTRAL TO EVENTUALLY A
NEGATIVE TILT...THUS STRONG FORCING FOR ASCENT. SATELLITE IMAGERY
ALSO DEPICTING A DEVELOPING WARM/MOIST CONVEYOR BELT ALONG THE
EAST COAST WITH LOTS OF LIGHTNING OFF THE MID ATLC COAST. MODELS
IN GOOD AGREEMENT THAT STRONG FORCING FOR ASCENT INDUCES
CYCLOGENESIS SOUTHEAST OF NANTUCKET LATER THIS MORNING...THEN
QUICKLY RACES NORTHEAST TOWARD NOVA SCOTIA. HOWEVER STRONG FORCING
LAGS BACK TO THE NORTHWEST YIELDING AN INVERTED TROUGH ACROSS
SOUTHERN NEW ENGLAND.
AS FOR QPF...SYSTEM IS VERY PROGRESSIVE WITH PRECIP BEGINNING BY
MID MORNING AND THEN QUICKLY EXITING 21Z-00Z FROM SOUTHWEST TO
NORTHEAST. THIS WOULD SUPPORT A MINOR QPF EVENT. HOWEVER FOR A 3-6
HR WINDOW QG FORCING IS IMPRESSIVE ALONG WITH DEEP LAYER MOISTURE
AND MARGINAL INSTABILITY. THIS SUGGEST A PERIOD OF STEADY PRECIP
WITH MODERATE TO HEAVY INTENSITY. GOOD MODEL AGREEMENT THAT THIS
WILL BE CENTERED ON 18Z...SO WILL SAY 16Z-20Z FOR WINDOW OF
HEAVIEST PRECIP.
REGARDING PTYPE AND SNOWFALL...HEAVIEST PRECIP FALLS IN WARM AIR
ACROSS RI AND EASTERN MA...WITH LESS QPF IN THE COLDER AIR ACROSS
CT/WESTERN MA INTO SOUTHWEST NH. THUS A CHALLENGING AND LOW
CONFIDENCE SNOWFALL AND PTYPE FORECAST...ESPECIALLY IN THE
TRANSITION ZONE WHERE RAIN/SNOW LINE SETS UP AND THEN OSCILLATES TO
THE NW AND BACK TO THE SE. FAIRLY CONFIDENT IN THE COLDER AIRMASS
ACROSS NORTHERN MA IN THE RT-2 CORRIDOR AND WEST OF INTERSTATE
495...NORTHWARD INTO NH A MODERATE TO HIGH RISK OF 2-4 INCHES OF
SNOWFALL. HIGHEST AMOUNTS IN THE HIGHER TERRAIN GIVEN MARGINAL BLYR
AND SFC TEMPS. THUS WILL ISSUE A WINTER WEATHER ADVISORY FOR THIS
AREA.
TRICKER SNOWFALL FORECAST IS FARTHER SOUTH AND EAST...FROM
SOUTHERN WORCESTER COUNTY /MA PIKE AREA/ NORTH-NORTHEAST INTO
NORTHWEST MIDDLESEX COUNTY AND EASTERN HILLSBORO COUNTY OF NH.
THIS WOULD INCLUDE A PORTION OF THE I495 CORRIDOR OF NORTHEAST MA.
THIS IS WHERE THE RAIN/SNOW LINE WILL LIKELY OSCILLATE. QUESTION
BECOMES WILL THE FORCING BE STRONG ENOUGH TO ERODE THE BLYR WARMTH
VIA DYNAMIC AND DIABATIC COOLING PROCESSES. SOME WEAK INSTABILITY
IN THIS AREA WHICH COULD FURTHER ENHANCE UPWARD VERTICAL MOTION.
IN ADDITION...MAX OMEGA PROGGED TO OCCUR IN THE FAVORABLE SNOW
GROWTH REGION. THIS WOULD INCREASE SNOW-LIQUID-RATIOS /SLR/ AND
INCREASE THE RISK OF HEAVIER SNOW TOTALS. GIVEN THE UNCERTAINTY
HERE WILL LEAVE THIS AREA OUT OF THE ADVISORY AND FORECAST 1-2
INCHES...BUT ISSUE A SPECIAL WEATHER STATEMENT TO ADDRESS THE
SNOWFALL POTENTIAL /3-4 INCHES POSSIBLE/ IN THIS REGION. AGAIN
HEAVIEST PRECIP ANTICIPATED 16Z-20Z /11AM-3PM/. IF ALL PARAMETERS
COME TOGETHER THERE COULD BE A NARROW BAND/SWATH OF 4-6 INCHES
SOMEWHERE FROM NORTHERN WORCESTER COUNTY/NORTHWEST MIDDLESEX
COUNTY INTO HILLSBOROUGH CTY OF NH. STAY TUNED...SHOULD BE AN
EXCITING AFTERNOON!
AS FOR THE REMAINDER OF THE REGION...LOOKS SNOW TO RAIN AND
PERHAPS BACK TO SNOW BEFORE ENDING. A MINOR SLUSHY ACCUMULATION
POSSIBLE EXCEPT MAINLY RAIN IN SOUTHEAST MA INTO CENTRAL-SOUTH RI
GIVEN WARM BLYR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
ANY LINGERING LIGHT SNOW ACROSS NORTHERN MA AND SOUTHWEST NH ENDS
DURING THE EARLY EVENING WITH A DRYING TREND DEVELOPING. PULSE OF
PRES RISES AND COLD AIR ADVECTION ON THE BACK SIDE WILL RESULT IN
BLUSTERY CONDITIONS OVERNIGHT. SHOULD BE ENOUGH OF A WESTERLY WIND
TO DRY THE LOW LEVELS TO PRECLUDE WIDESPREAD BLACK ICE. ALTHOUGH
CAN/T COMPLETELY RULE OUT SOME PATCHY ICE.
SUNDAY...
LOW AMPLITUDE MID LEVEL TROUGH RACES ACROSS THE AREA. WEAK FORCING
AND LACK OF DEEP LAYER MOISTURE SHOULD LIMIT ANY SNOW SHOWER
ACTIVITY TO SCATTERED IN AREAL COVERAGE. BLUSTERY AND COOLER. HIGHS
IN THE 30S BUT WIND CHILLS IN THE 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HEADLINES...
* CHANCE FOR LIGHT SNOW SHOWERS ACROSS THE INTERIOR EARLY SUNDAY
NIGHT
* GENERALLY DRY CONDITIONS EXCEPT FOR SOME OCEAN EFFECT SNOW SHOWERS
ACROSS MID AND OUTER CAPE COD AND NANTUCKET TUESDAY AND TUESDAY
NIGHT
* TEMPERATURES CONTINUE TO TURN COLDER THROUGH LATE NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
OVERALL...UPPER LEVEL PATTERN ACROSS NORTH AMERICA REMAINS THE
SAME WITH HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN U.S. WITH
AMPLIFYING TROUGH ACROSS THE EAST. MODELS REMAIN IN GOOD AGREEMENT
WITH THIS ASPECT. IN THE LONG RANGE...MODELS SHOWING A STRONG
SIGNAL OF ANOTHER ARCTIC BLAST WORKING OUT OF CENTRAL CANADA
ACROSS THE NORTH CENTRAL U.S. THROUGH THE GREAT LAKES INTO THE
NORTHEAST BEGINNING AROUND THE MONDAY TIMEFRAME THROUGH NEXT WEEK.
WEAK SHORT WAVES MOVE ACROSS THE REGION BUT...WITH THE GENERAL
W-NW SURFACE AND UPPER FLOW...LOOKS LIKE SYSTEMS WILL MOVE THROUGH
MAINLY DRY THOUGH MAY SEE A FEW SNOW SHOWERS ACROSS THE HIGHER
TERRAIN. WITH EACH SHORT WAVE...REINFORCING ARCTIC AIRMASS MOVES
IN...WITH THE COLDEST NOTED DURING THE WED-THU TIMEFRAME. CURRENT
FORECAST SUGGESTS OVERNIGHT LOWS DROPPING BELOW ZERO ACROSS THE
INTERIOR.
WITH RATHER GOOD CONSISTENCY AMONG THE MODEL SUITE...USED A BLEND OF
THE GFS AND ECMWF ALONG WITH THEIR ENSEMBLES.
DETAILS...
SUNDAY NIGHT THROUGH MONDAY NIGHT...SHORT WAVE MOVES ACROSS SUN
NIGHT INTO EARLY MONDAY WITH LEFTOVER SNOW SHOWERS ACROSS THE
INTERIOR. WINDS SHIFT TO NW AND H85 TEMPS DROP TO -7C TO -12C BY
12Z MON. A DRY SHORT WAVE MOVES ACROSS MON NIGHT WITH ANOTHER WAVE
OF ARCTIC AIR MOVING IN. H85 TEMPS DROP MON NIGHT TO -11C TO -18C
BY EARLY TUE MORNING. EXPECT OVERNIGHT LOWS MON NIGHT DOWN TO THE
SINGLE DIGITS WELL INLAND AND OVER THE HIGHER TERRAIN TO THE LOWER
20S ON OUTER CAPE COD AND NANTUCKET.
TUESDAY THROUGH WEDNESDAY NIGHT...GENERALLY DRY BUT FRIGID
CONDITIONS EXPECTED. WITH WINDS VEERING TO N-NW...CAN SEE SCT
OCEAN EFFECT SNOW SHOWERS POSSIBLY MOVING ACROSS THE MID AND OUTER
CAPE AS WELL AS NANTUCKET THROUGH TUE NIGHT. BIG QUESTION WILL BE
HOW MUCH OF A NORTHERLY COMPONENT TO THE WIND THERE WILL BE TO
ALLOW FOR SNOW SHOWERS TO MAKE IT IN. H85 TEMPS CONTINUE TO
DROP...AS LOW AS -17C TO -20C ACROSS THE REGION LATE WED NIGHT.
EXPECT LOWS WED NIGHT RANGING FROM ZERO TO 5 BELOW ACROSS S NH AND
N MA TO THE MID TEENS ON THE OUTER CAPE AND ISLANDS. THIS WILL
COMBINE WITH NW WINDS UP TO 10 MPH TO BRING BITTERLY COLD WIND
CHILLS. WILL MONITOR FOR POSSIBLE WIND CHILL ADVISORIES ACROSS
PORTIONS OF THE INTERIOR.
THURSDAY-FRIDAY...MAY SEE A CLIPPER SYSTEM WORK INTO THE REGION
DURING THURSDAY BUT WILL BE MOISTURE STARVED SO EXPECTING ONLY
WIDELY SCT SNOW SHOWERS AS IT QUICKLY MOVES THROUGH. LARGE HIGH
PRES WILL BUILD IN FOR THU NIGHT AND FRI. TEMPS FORECAST TO REMAIN
WELL BELOW SEASONAL NORMALS. MAY NEED WIND CHILL ADVISORIES ON THU
NIGHT.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY/...
TODAY...
VFR/MVFR TO START BUT QUICKLY LOWERING TO MVFR-IFR BY 16Z-18Z.
HEAVIEST PRECIP ALONG WITH LOWEST CIGS/VSBYS WILL BE FROM 16Z-21Z
ACROSS RI/EASTERN MA INTO SOUTHERN NH. LOW PROB OF A FEW HOURS OF
LIFR OVER E MA. MAINLY ALL SNOW INTERIOR ESPECIALLY HIGHER
TERRAIN /KORH AND KMHT/ WITH A MIX OF RAIN/SNOW ELSEWHERE. AN INCH
OR TWO OF SNOW ACCUMULATION LIKELY WELL INLAND ESPECIALLY FROM
KORH TO KMHT. HOWEVER LOW RISK FOR A NARROW SWATH OF 3 TO 4 INCHES
IN THIS REGION IF PRECIP REMAINS MAINLY SNOW. CONFIDENCE LOW ON
EXACT POSITION AND EVOLUTION OF RAIN-SNOW LINE.
TONIGHT...
IMPROVING CONDITIONS WITH MVFR TO START AND VFR AFTER 06Z. ANY
LINGERING SNOW IN SOUTHERN NH WILL END 03Z-06Z. MODERATE TO HIGH
CONFIDENCE. MODEST WNW WIND DEVELOPS.
SUNDAY...
MARGINAL VFR/MVFR IN SCATTERED SNOW SHOWERS. NO ACCUMULATION
EXPECTED. GUSTY WNW WIND.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. A MIX OF RAIN AND SNOW
EXPECTED. HOWEVER SURFACE TEMPS SHOULD BE WARM ENOUGH TO PRECLUDE
MUCH IF ANY ACCUMULATION. HEAVIEST PRECIP 16Z-20Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. STEADIEST PRECIP
12Z-18Z THEN TAPERING OFF.
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE.
SUNDAY NIGHT AND MONDAY...VFR. PATCHY MVFR CIGS/VSBYS IN ANY SNOW
SHOWERS MAINLY ACROSS THE INTERIOR...THEN ON MONDAY ACROSS CAPE
COD AND THE ISLANDS. SW WINDS GUSTING UP TO 20-25 KT EARLY SUN
NIGHT THEN SHIFT TO W AND DIMINISHING.
MONDAY NIGHT...MAINLY VFR. NW WIND GUSTS UP TO 20 KT ON THE MID
AND OUTER CAPE AS WELL AS NANTUCKET.
TUESDAY THROUGH WEDNESDAY...VFR. LOCAL MVFR CONDITIONS ACROSS
OUTER CAPE COD AND NANTUCKET WITH ANY OCEAN EFFECT SNOW SHOWERS
TUESDAY INTO EARLY TUESDAY NIGHT. BREEZY N-NW WINDS WITH GUSTS UP
TO 25 KT ALONG THE COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE TO HIGH FORECAST CONFIDENCE THROUGH SUNDAY.
TODAY...
BROAD AREA OF LOW DEVELOPS OVER NEW ENGLAND AND THE NEARBY
WATERS. RAIN AND SNOW REDUCES VSBY. LIGHT WINDS GIVEN WEAK LOW
PRES PASSING OVERHEAD.
TONIGHT...
STRENGTHENING LOW OVER GEORGES BANK RACES NE INTO THE MARITIMES.
MODEST WNW WINDS 15-20 KT GUSTS UP TO 25 KT POSSIBLE. ANY
SNOW/RAIN ENDS EARLY WITH IMPROVING VSBY.
SUNDAY...
WSW WINDS 15-25 KT. SCATTERED SNOW SHOWERS POSSIBLE. GOOD VSBY.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...MODERATE CONFIDENCE.
SUNDAY NIGHT...W GALES LIKELY WITH GUSTS UP TO 35-40 KTS OVER THE
OPEN WATERS. SEAS BUILDING UP TO 10-12 FEET.
MONDAY...LEFTOVER W GALE GUSTS EARLY. GUSTS WILL CONTINUE AT 25-30
KT...HIGHEST ON THE OUTER WATERS. ARCTIC FRONT CROSSES THE WATERS
WITH OCEAN EFFECT SNOW SHOWERS DEVELOPING MON NIGHT. WINDS SHIFT TO
NW AND DIMINISH WITH SEAS SLOWLY SUBSIDING.
MONDAY NIGHT THROUGH WEDNESDAY...NW WINDS WILL OCCASIONALLY GUST UP
TO 25 KT. SEAS AROUND 5 FT MAINLY ON THE OUTER WATERS WITH A CHANCE
OF LIGHT FREEZING SPRAY. OCEAN EFFECT LOW CLOUDS AND SNOW WILL CAUSE
VSBY RESTRICTIONS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
MAZ002>004-008-010-026.
NH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NHZ011-
012-015.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR ANZ231>234.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ237.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ235-250-
254>256.
&&
$$
SYNOPSIS...NOCERA/EVT
NEAR TERM...NOCERA/DUNTEN
SHORT TERM...NOCERA
LONG TERM...EVT
AVIATION...NOCERA/EVT
MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
410 AM EST SAT JAN 18 2014
.SYNOPSIS...
A COLD FRONT AND ASSOCIATED AREA OF LOW PRESSURE WILL CONTINUE
TO MOVE TO OUR NORTHEAST TODAY. A WEAKENING AREA OF LOW PRESSURE AND
ASSOCIATED COLD FRONT WILL QUICKLY MOVE ACROSS THE AREA ON SUNDAY. A
STRONGER AREA OF LOW PRESSURE WILL SWING EASTWARD ACROSS SOUTHERN
CANADA SUNDAY NIGHT INTO MONDAY, DRAGGING A FRONTAL BOUNDARY ACROSS
THE EAST COAST SUNDAY NIGHT INTO MONDAY. COLD HIGH PRESSURE WILL
BUILD TO OUR SOUTHWEST TUESDAY INTO EARLY WEDNESDAY, BEFORE ANOTHER
LOW PRESSURE SYSTEM AND ASSOCIATED FRONTAL BOUNDARIES AFFECT THE
AREA WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE WILL RETURN TO THE
EAST COAST FOR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DECENT BAND PUSHING THROUGH THE NORTHERN PORTIONS OF OUR CWA AT THIS
EARLY MORNING HOUR THOUGH IT DOES APPEAR WORSE THAN IT PROBABLY
IS...BRIGHT BANDING. THERE IS SOME WEAK 850-700MB FGEN ASSOCIATED
WITH A PASSING LOW-LEVEL WARM FRONT AS DESIGNATED BY TEMPERATURES
ACROSS SOUTHERN DELMARVA INCHING CLOSE TO 50F WHILE FURTHER NORTH
ARE BARELY AROUND FREEZING.
DECIDED TO KEEP THE ADVISORY GOING THROUGH AT LEAST THE NEXT
FORECAST UPDATE THOUGH IT IS LOOKING RATHER BENIGN AT THIS POINT.
BOTH THE RUC AND THE HRRR ARE FAIRLY CONSISTENT KEEPING THE BEST QPF
TO OUR WEST WITH THE NEGATIVE MID-LEVEL TROUGH AND SURFACE COLD
FRONT. AS THE TROUGH SHEARS ALONG TOWARDS THE NORTHEAST IT LOOKS TO
OPEN UP AND BECOME FLATTER WHICH SHOULD BRING AN END TO A MAJORITY
OF THE PRECIPITATION. DROPPED THE AMOUNT OF QPF FOR THIS MORNING
WHICH ULTIMATELY DECREASED THE SNOW AMOUNTS ACROSS THE REGION.
THOUGH THERE IS PRETTY GOOD OMEGA WITHIN THE SNOW GROWTH ZONE THE
SYSTEM IN GENERAL IS VERY QUICK MOVING NOT ALLOWING FOR MORE THAN A
COUPLE INCHES ACROSS THE HIGHER ELEVATIONS EARLY THIS MORNING.
THE AFOREMENTIONED COLD FRONT IS RIGHT ON OUR WESTERN DOORSTEP AND
THERE ARE A FEW GUSTS CLOSE TO 20MPH NOW THOUGH THE DRIER AIR IS
STILL WELL TO THE WEST SO IT WILL TAKE A BETTER PART OF THE MORNING
TO SEE DEWPOINTS DROP. THE FRONT WILL BE OFF TO THE EAST THIS
AFTERNOON GIVING WAY TO STRONG WESTERLY WINDS WHICH WILL HAVE THE
BIGGEST IMPACT FOR TODAY`S SENSIBLE WEATHER. THE AIRMASS CONTINUES TO
COOL AND WE ARE EXPECTING DAYTIME HIGHS TO REACH INTO THE LOW TO
MID-30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
WE SHOULD BE BETWEEN WAVES, AGAIN, TONIGHT WITH WEAK RIDGING
BUILDING IN, THOUGH IT WON`T LAST LONG. THE NEXT CLIPPER SHOULD DIG
DEEPER TO OUR WEST LATE TONIGHT TO QUICKLY RUSH TOWARDS THE EAST.
MODELS ARE DECENT AGREEMENT THAT ALL PRECIPITATION SHOULD HOLD OFF
UNTIL LATER SUNDAY MORNING SO WE KEEP THE FORECAST DRY OVERNIGHT
WITH CLEARING CONDITIONS. THIS SHOULD ALLOW FOR DECENT RADIATIONAL
COOLING CONDITIONS IN OUR SHELTERED LOCATIONS. A BLEND OF THE
MET/MAV WAS USED FOR LOWS.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST CONTINUES TO BE DOMINATED BY BROAD TROUGHING
ACROSS THE EAST COAST, WITH SEVERAL SHORT WAVES AND CLIPPER SYSTEMS
EXPECTED TO AFFECT THE AREA. NONE OF THE SYSTEMS LOOK TO BE ABLE TO
PRODUCE WIDESPREAD PRECIPITATION ACROSS THE AREA. ABOVE NORMAL
TEMPERATURES ARE EXPECTED TO START OFF THE PERIOD, FOLLOWED BY QUITE
A BIT OF A COOL DOWN AS COLD POLAR AIR INFILTRATES THE AREA.
THE FIRST OF THE SHORT WAVES/CLIPPER SYSTEMS IS EXPECTED TO MOVE
THROUGH THE AREA EARLY SUNDAY. WE WILL MAINTAIN A SLIGHT CHANCE OF
PRECIPITATION AT THIS POINT, ALTHOUGH MODELS ARE BECOMING LESS
EXCITED ABOUT MEASURABLE PRECIP ACROSS THE AREA AS COMBINED
MOISTURE/LIFT ARE LACKING SOME AS THE SYSTEM WEAKENS AS IT MOVES
INTO OUR AREA. SUNDAY IS EXPECTED TO BE ABOVE NORMAL AS THICKNESSES
INCREASE BEHIND THE DEPARTING SHORT WAVE AND SKIES MAY CLEAR SOME TO
ALLOW SOME WARMING. SUNDAY NIGHT IS EXPECTED TO REMAIN DRY AND ABOVE
NORMAL AS THICKNESSES CONTINUE TO INCREASE SOME WITH A SOUTHWEST
FLOW ALOFT.
ON SUNDAY NIGHT INTO MONDAY, AN AREA OF LOW PRESSURE WILL BE MOVING
THROUGH SOUTHERN CANADA, PULLING A COLD FRONT TOWARD OUR AREA. THE
FRONTAL BOUNDARY IS EXPECTED TO MOVE THROUGH THE AREA DURING THE DAY
MONDAY INTO MONDAY EVENING. THE GREATEST POTENTIAL FOR PRECIPITATION
LOOKS TO REMAIN TO OUR NORTH AS THE STRONGEST MOISTURE/LIFT
COMBINATION DOES NOT LOOK TO MAKE IT INTO OUR AREA. HOWEVER, WE WILL
MAINTAIN A SLIGHT CHANCE ACROSS OUR NORTHERN THIRD OF THE FORECAST
AREA AS GUIDANCE DOES INDICATE MINIMAL QPF ACROSS OUR FAR NORTHERN
ZONES. TEMPERATURES MONDAY ARE EXPECTED TO BE SEVERAL DEGREES ABOVE
NORMAL AHEAD OF THE FRONTAL BOUNDARY, BUT BEHIND THE FRONT,
TEMPERATURES WILL BE TAKING A NOSE DIVE. LOWS OVERNIGHT MONDAY INTO
TUESDAY MORNING WILL LIKELY FALL BELOW NORMAL.
TUESDAY IS CURRENTLY EXPECTED TO REMAIN PRECIPITATION FREE ACROSS
THE AREA. AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG THE
FRONTAL BOUNDARY TO OUR EAST, BUT MAY DEVELOP FAR ENOUGH OFFSHORE TO
KEEP THE PRECIPITATION AWAY FROM OUR AREA. HIGH PRESSURE WILL
BRIEFLY TRY TO BUILD INTO THE AREA LATE TUESDAY NIGHT INTO
WEDNESDAY, SO DRY WEATHER IS EXPECTED TO CONTINUE. THE BIG THING TO
NOTE FOR THIS PERIOD WILL BE THE COLD ONCE AGAIN. TEMPERATURES FROM
TUESDAY NIGHT-WEDNESDAY NIGHT COULD BE AT LEAST 10-15 DEGREES BELOW
NORMAL. THIS COMBINED WITH GUSTY WINDS WILL GREAT VERY LOW WIND
CHILLS ONCE AGAIN ACROSS THE AREA.
ANOTHER CLIPPER TYPE SYSTEM IS EXPECTED TO AFFECT THE AREA WEDNESDAY
NIGHT INTO THURSDAY. AGAIN, MODELS AREN`T IN AGREEMENT WITH QPF
AMOUNTS AS THE GFS HAS MINIMAL AMOUNTS, IF ANY, WHILE THE ECMWF HAS
QUITE A BIT MORE. FOR NOW WE WILL KEEP SLIGHT CHANCE DUE TO
UNCERTAINTY, AND LET LATER FORECAST INCREASE IF GREATER CONFIDENCE
BUILDS. TEMPERATURES WILL REMAIN COLD AND BELOW NORMAL THURSDAY AND
FRIDAY, ALTHOUGH A SLIGHT WARMING TREND BEGINS TO DEVELOP.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR OUTSIDE OF RDG/ABE EARLY THIS MORNING. AREAS OF SNOW
SHOWERS NORTH AND WEST OF ABE/RDG WILL CONTINUE TO MOVE OFF TOWARDS
THE NORTH ALLOWING THESE TERMINALS TO REBOUND BACK TO VFR. OTHERWISE
A STIFF GUSTY WESTERLY WIND IS EXPECTED TODAY WITH GUSTS UPWARDS OF
25 TO POSSIBLY 30 KNOTS.
TONIGHT...VFR. LIGHT AND VARIABLE WINDS WITH CLEARING SKIES.
OUTLOOK...
SUNDAY-SUNDAY NIGHT...MOSTLY VFR. LOWER CIGS/VSBY POSSIBLE SUNDAY
MORNING IF SHOWERS OCCUR. GUSTY SOUTHWEST WINDS AROUND 20 KT DURING
THE DAY.
MONDAY-MONDAY NIGHT...MOSTLY VFR. LOWER CIGS/VSBY POSSIBLE MONDAY IF
SHOWERS OCCUR, MAINLY NORTHERN TAF SITES. GUSTY WEST-SOUTHWEST WINDS
20-25 KT DURING THE DAY.
TUESDAY-WEDNESDAY...MOSTLY VFR. GUSTY NORTH-NORTHWEST WINDS 15-20
KT.
&&
.MARINE...
SMALL CRAFT CONTINUES ACROSS ALL OUR WATERS AS A QUICK MOVING COLD
FRONT APPROACHES FROM THE WEST THIS MORNING. AS THE FRONT PASSES
THROUGH STRONG GUSTY WESTERLY WINDS WILL KICK IN...GUSTS AROUND 30
KNOTS THROUGH THE LATE EVENING HOURS. WINDS AND SEAS WILL RELAX A
BIT TONIGHT, POSSIBLY BELOW SCA CRITERIA, BUT SHOULD BEGIN TO CLIMB
UPWARDS AGAIN LATE SUNDAY MORNING.
OUTLOOK...
SUNDAY...SCA IN EFFECT.
SUNDAY NIGHT...SCA CONDITIONS EXPECTED, POSSIBLE NEAR GALE FORCE
GUSTS.
MONDAY-TUESDAY...SCA CONDITIONS LIKELY TO REMAIN.
TUESDAY NIGHT...SCA CONDITIONS POSSIBLE EARLY, BEFORE DIMINISHING
OVERNIGHT.
WEDNESDAY...SUB-ADVISORY CONDITIONS EXPECTED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ054-055.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ430-431-
451>455.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 6 PM EST SUNDAY
FOR ANZ450.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...ROBERTSON
AVIATION...HEAVENER/ROBERTSON
MARINE...HEAVENER/ROBERTSON
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
519 PM EST SAT JAN 18 2014
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA LATE
TONIGHT AND EARLY SUNDAY. A PRESSURE RIDGE WILL BE SOUTH OF THE AREA
SUNDAY THROUGH MONDAY. ANOTHER COLD FRONT WILL SWEEP THROUGH THE
AREA TUESDAY. ARCTIC HIGH PRESSURE BEHIND THIS FRONT WILL DOMINATE
WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE APPROACHING COLD FRONT WILL BE NEAR THE FORECAST AREA TOWARD
SUNRISE. LATEST HRRR INDICATES SHOWERS ASSOCIATED WITH THE FRONT
WILL DISSIPATE BEFORE GETTING OVER THE MOUNTAINS. ALL OF THE GFS
AND NAM MOS GIVE POPS LESS THAN 20 PERCENT AND THIS APPEARS
REASONABLE BECAUSE OF THE PRESSURE RIDGE SOUTH OF THE AREA
CONTINUING TO LIMIT MOISTURE AHEAD OF THE FRONT. MIXING AND
CLOUDINESS SHOULD HELP HOLD UP TEMPERATURES TONIGHT. LEANED
TOWARD THE WARMER TEMPERATURE GUIDANCE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
FURTHER DRYING WILL OCCUR BEHIND THE COLD FRONT SUNDAY MORNING. IT
WILL BE BREEZY. THE NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS
NEAR 25 KNOTS. A LAKE WIND ADVISORY MAY BE NEEDED. THE SURFACE RIDGE
SOUTH OF THE AREA WILL CONTINUE TO MAINTAIN A DRY WESTERLY FLOW WITH
LITTLE MOISTURE RECOVERY AHEAD OF THE NEXT COLD FRONT APPROACHING
MONDAY. THE TEMPERATURE GUIDANCE WAS CLOSE. WARMING AHEAD OF THE
COLD FRONT WILL SUPPORT ABOVE NORMAL HIGH TEMPERATURES MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE GFS AND ECMWF MAINTAIN UPPER-LEVEL TROUGHING OVER THE EASTERN
PART OF THE NATION DURING THE MEDIUM-RANGE PERIOD. THE MODELS
INDICATE LITTLE MOISTURE ASSOCIATED WITH REINFORCING COLD FRONTS
TUESDAY AND THURSDAY. THE GFS...ECMWF...AND EKD MOS SUPPORT NEAR
NORMAL TEMPERATURES TUESDAY DURING THE TIME OF FRONTAL PASSAGE. THE
GUIDANCE INDICATES MUCH BELOW NORMAL TEMPERATURES DURING THE REST
OF THE PERIOD.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE TAF PERIOD.
RIDGE OF HIGH PRESSURE CURRENTLY CENTERED OVER THE REGION WILL
RETREAT SOUTHWARD THIS EVENING AS ANOTHER COLD FRONT APPROACHES
FROM THE WEST THEN CROSSES THE AREA TOWARD DAYBREAK SUNDAY
MORNING. WINDS WILL CONTINUE TO BE THE MAIN ISSUE THROUGH THE
PERIOD. CURRENT WESTERLY WINDS AT 12 TO 14 KNOTS WITH GUSTS UP TO
22 KNOTS WILL PERSIST THROUGH 23Z...THEN SUBSIDE TO AROUND 8
KNOTS AND BACK TO SOUTHERLY BY 19/04Z...FINALLY VEERING BACK TO
WESTERLY AROUND 13 KNOTS WITH GUSTS UP TO 24 KNOTS FROM 19/11
THROUGH THE END OF THE PERIOD. AS THE COLD FRONT PASSES THERE WILL
BE SOME LOW AND MID LEVEL CLOUDS...HOWEVER NO RESTRICTIONS ARE
EXPECTED.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS POSSIBLE AT TIMES
SUNDAY AFTERNOON THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
425 PM CST SAT JAN 18 2014
.DISCUSSION...
228 PM CST
REST OF TODAY...
SURFACE LOW IS DIVING SOUTHEAST INTO WEST CENTRAL ILLINOIS THIS
AFTERNOON WITH A NARROW BAND OF MODERATE TO HEAVY SNOW STRETCHING
ACROSS NORTH CENTRAL ILLINOIS INTO NORTHWEST INDIANA. SYSTEM HAS
BEEN FAIRLY WELL BEHAVED SO FAR WITH REPORTS OF AROUND 3-4 INCHES IN
THE AREAS THAT HAVE SEEN THE MOST SNOW THUS FAR. DECENT PACKING OF
THE PRESSURE IS NOTED ON THE 280-285K THETA SURFACES...WITH THE BEST
ASCENT PROGGED TO GRADUALLY SHIFT SOUTHEAST OUT OF THE CWA BY MID
EVENING. RAP H7 F-GEN SEEMS TO INITIALIZE NICELY...LINING UP WELL
WITH RADAR AND STRETCHING FROM THE SOUTH SUBURBS INTO NORTHWEST
INDIANA...AND PIVOTING TO THE EAST OUT OF THE AREA. THE RAP DOES
PICK UP ON F-GEN RESTRENGTHENING THIS EVENING OVER A SIMILAR AREA
AND GRADUALLY SINKING SOUTH ACROSS THE REMAINDER OF THE CWA BY LATE
THIS EVENING. WITH THIS IN MIND...DID SLOW DOWN THE TIMING OF SNOW
ENDING THIS EVENING IN THE GRIDS BY A FEW HOURS.
TONIGHT THROUGH SUNDAY...
THE POTENT UPPER WAVE THAT IMPACTED THE AREA TODAY WILL DEPART
ACROSS THE OHIO VALLEY THIS EVENING AND TONIGHT WITH MID/UPPER
RIDGING BUILDING INTO THE UPPER MIDWEST AND WESTERN LAKES REGION.
STRONG SFC PRESSURE RISES WILL MOVE IN BEHIND THE QUICKLY DEPARTING
LOW AND IS EXPECTED TO LEAD TO BREEZY CONDITIONS THIS
EVENING...MAINLY SOUTH OF I-80. FAIRLY STRONG HEIGHT RISES ALOFT
WILL ALSO OVERSPREAD THE AREA...PERSISTING THROUGH THE DAY SUNDAY
AND SHOULD PROVIDE A BRIEF RESPITE IN THE PRECIPITATION. ONCE THE
SURFACE/LOW LEVEL RIDGE AXIS PASSES OVER THE AREA LATE
TONIGHT...WINDS WILL BACK TO THE SOUTHWEST AND WARMER AIR WILL
ADVECT OVERHEAD...WITH H85 TEMPS RISING TO AROUND 2-3C BY SUNDAY
MORNING. SURFACE TEMPERATURES SHOULD REBOUND TO NEAR THE FREEZING
MARK DURING THE DAY SUNDAY...OTHERWISE SHOULD BE A QUIET WEATHER DAY
TOMORROW.
MONDAY THROUGH TUESDAY ...
MAIN CONCERN AS WE HEAD INTO NEXT WEEK WILL BE THE RETURN OF COLD
ARCTIC AIR. WEST COAST RIDGE IS PROGGED TO AMPLIFY OVER THE
WEEKEND...STRETCHING NORTH ACROSS ALASKA WHICH IN COMBINATION WITH A
DEEPENING LOW OVER ONTARIO WILL DISLODGE AIR FROM THE ARCTIC SOUTH
INTO THE NORTHERN LAKES REGION SUNDAY INTO MONDAY. THE LEADING EDGE
OF THIS COLD AIRMASS WILL SINK SOUTH BEHIND A COLD FRONT THAT WILL
PASS SOUTH OVER THE AREA EARLY MONDAY. TEMPERATURES BEHIND THE FRONT
ARE EXPECTED TO BE FALLING THROUGH THE DAY MONDAY. H85 TEMPS ARE
EXPECTED TO FALL TO AROUND -20C AND GENERALLY PERSIST THROUGH THE
END OF THE WEEK. STEEP LOW LEVEL LAPSE RATES DEVELOP BEHIND THE
FRONT AND APPEARS FAVORABLE FOR COLD AIR CU WITH SOME FLURRIES
DEVELOPING IF NOT A FEW SNOW SHOWERS. ACROSS NORTHWEST
INDIANA...WILL ALSO HAVE TO KEEP AN EYE ON THE LAKE EFFECT MACHINE
WHICH WILL BE RAMPING UP...AND APPEARS VERY FAVORABLE TO SEE SOME
SIGNIFICANT SNOW ACCUMULATIONS IN OR NEAR OUR EASTERN COUNTIES.
OVER LAND...LAPSE RATES WEAKEN MONDAY NIGHT AND APPEARS THAT WE
SHOULD BE WELL ENTRENCHED IN THE COLD/DRY AIR TUESDAY LEADING TO
MOST AREAS STAYING DRY OUTSIDE OF THE LAKE EFFECT.
WEDNESDAY THROUGH FRIDAY...
REGION REMAINS UNDER AN ACTIVE NORTHWEST FLOW PATTERN THROUGH THE
END OF NEXT WEEK RESULTING IN SEVERAL PERIODS OF SNOWFALL AS WAVES
ROTATE ACROSS THE AREA. MODELS HAVE BEEN TRENDING TOWARDS A MORE
ROBUST UPPER WAVE DROPPING ACROSS THE REGION MIDWEEK. SHOULD THIS
PAN OUT...MIGHT SEE A BRIEF/MODEST WARMUP AHEAD OF THE SYSTEM...BUT
THEN EVEN COLDER AIR SPILLING BEHIND. BOTH GEM AND ECMWF INDICATE
TEMPS FALLING TO AROUND -24C AT H85 WEDNESDAY. WHILE ITS PROBABLY A
BIT FAR OUT TO START TALKING LOW TRACK AND POTENTIAL SNOW...FOR NOW
AT LEAST MODELS INDICATE THE LOW WILL STAY NORTH OF THE CWA.
TEMPERATURES SHOULD REMAIN WELL BELOW NORMAL WEDNESDAY AND
THURSDAY...AND ARE EXPECTED TO BEGIN TO MODERATE SOME BY FRIDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SNOW BECOMING MORE INTERMITTENT BEFORE ENDING EARLY THIS
EVENING...MAY SEE GREATER VARIABILITY IN VSBY WITH TIME AS SNOW
COVERAGE WANES.
* EAST-SOUTHEAST WINDS TURNING NORTHEAST LATE AFTERNOON...THEN
NORTH-NORTHWEST TOWARD 02/03Z.
MDB
//DISCUSSION...UPDATED 22Z...
MAIN AXIS OF HEAVY SNOW HAS BEEN SHIFTING SOUTHEAST IN THE LAST
FEW HOURS BUT INTERMITTENT BANDS OF MORE INTENSE SNOW STILL REMAIN
NEAR THE TERMINALS. WITH THE LOW PASSING TO THE SOUTH...WARM
ADVECTION CONTINUES TO GENERATE SOME NORTHWARD MOVING SNOW BANDS
INTO THE CHICAGO/NW INDIANA AREA BUT COVERAGE IS BECOMING MORE
BROKEN SO A HIGHER VARIABILITY IN CONDITIONS IS LIKELY TO
DEVELOP...WITH 3-5SM VSBY BECOMING POSSIBLE AT ORD/MDW/DPA TOWARDS
23-00Z WITH PERIODIC REDUCTIONS TO 1-2SM STILL POSSIBLE GOING INTO
THE EARLY EVENING AS SNOW BANDS AFFECT THE AREA. CIGS ARE ALSO
BECOMING VARIABLE BUT IMPROVING AND EXPECT THEM TO REMAIN MAINLY
MVFR OR BETTER. WINDS ARE BEGINNING TO TURN EASTERLY IN THE
CHICAGO AREA WITH NORTHEAST WINDS BACK TOWARDS RFD...SO THE SHIFT
TO NORTHEAST IS UNDERWAY AND WILL SPREAD EASTWARD. A SHIFT TO
NORTH-NORTHWEST IS STILL EXPECTED GOING INTO THE MID EVENING.
MDB
FROM 18Z...
SNOW HAS SPREAD OVER THE TAF SITES AND WILL CONTINUE THROUGH THE
AFTERNOON. THE HEAVIEST SNOW WILL REMAIN TO THE SOUTH OF THE TAF
SITES...HOWEVER RADAR AND METEOROLOGICAL ANALYSIS INDICATE THAT
POCKETS OF HEAVIER SNOW EXTEND NORTH FROM THERE WITH 1/2-3/4SM AT
TIMES NEAR OR AT TAF SITES...WITH ACCOMPANYING TEMPORARY SNOWFALL
RATES OF ONE INCH PER HOUR OR SLIGHTLY HIGHER. WINDS WILL CONTINUE
TO BACK TOWARD EASTERLY BY SUNSET AS THE SYSTEM LOW PRESSURE
PASSES TO THE SOUTH. THESE WINDS WILL THEN BACK QUICKLY TO THE
NORTHWEST BY MID EVE OR SO. SPEEDS WILL BE ON THE INCREASE QUICKLY
ON SUNDAY AS THE PRESSURE GRADIENT TIGHTENS. ANY LINGERING LOW
CLOUDS FROM LATE TONIGHT SHOULD DISSIPATE QUICKLY ON SUNDAY
MORNING.
MTF
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN SNOW COVERAGE WANING...THOUGH NOT ENDING FOR
A FEW HOURS...HIGH CONFIDENCE IN MORE VARIABLE VSBY...WITH 3-5SM
BECOMING MORE LIKELY BUT PERIODIC 1-2SM OCCURRING AS SNOW BANDS
PASS.
* HIGH CONFIDENCE IN WIND DIRECTION AND SPEED TRENDS...MEDIUM-HIGH
CONFIDENCE IN TIMING OF SHIFT TO NORTH-NORTHWEST.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MAINLY VFR. A FEW FLURRIES NORTH OF ORD/MDW.
MONDAY...SLGT CHC OF SNOW SHOWERS.
TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...PERIODIC CHANCES FOR SNOW SHOWERS AND MVFR.
OTHERWISE VFR.
MTF
&&
.MARINE...
307 PM CST
NO CHANGES WERE MADE TO THE ONGOING HEADLINES AS GALES ARE STILL
EXPECTED.
THE LOW IS OVER THE MID MISSISSIPPI RIVER VALLEY AND WHILE IT IS
FILLING SLOWER THAN PREVIOUSLY EXPECTED...IT IS STILL EXPECTED TO
FILL AS MOVES ACROSS SOUTHERN IL. A SECOND LOW IS MOVING INTO
NORTHERN QUEBEC AND ITS COLD FRONT WILL SINK SOUTH DOWN THE LAKE
SUNDAY AND SUNDAY NIGHT. AS THE GRADIENT TIGHTENS
TONIGHT...SOUTHWEST WINDS INCREASE TO GALES OVER THE NORTHERN HALF
TO THE LAKE. WINDS TURN WEST ACROSS THE LAKE AND INCREASE TO LOW END
GALES BY SUNDAY MORNING. WINDS DIMINISH SUNDAY AFTERNOON...AND MAY
COME DOWN BEFORE THE END OF THE GALE WARNING.
WINDS THEN TURN NORTH BEHIND THE FRONT SUNDAY NIGHT AND REMAIN AT 20
TO 25 KT...POSSIBLY UP TO 30 KT AT TIMES...THROUGH MONDAY NIGHT.
HIGH PRESSURE MOVES OVER THE UPPER PLAINS MONDAY NIGHT AND SLIDES
SOUTHEAST REACHING THE SE US WEDNESDAY. WINDS DIMINISH TUESDAY AND
BECOME WEST. GUIDANCE DIFFERS IN REGARDS TO THE PATTERN MID NEXT
WEEK. THE ECMWF FEATURES A DEEP LOW OVER THE LAKE WHILE THE GFS HAS
A WEAK SURFACE TROUGH. BOTH DO FEATURE A HIGH MOVING OVER THE
PLAINS. SO HAVE WINDS BECOMING NORTHWEST AND/OR NORTH WEDNESDAY
NIGHT...AND IF THE LOW IS DEEPER...WINDS COULD BE STRONGER. AS THE
HIGH PASSES TO THE SOUTH LATE NEXT WEEK...WINDS WEAKEN AND BECOME
WEST.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019-ILZ020-
ILZ021-ILZ022-ILZ032 UNTIL 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 PM
SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 PM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SUNDAY TO 3 PM
SUNDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...MIDNIGHT SUNDAY TO 3 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...3 AM SUNDAY TO 10
PM SUNDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...9 AM SUNDAY TO 4 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM SUNDAY TO 9
AM SUNDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
308 PM CST SAT JAN 18 2014
.MESOSCALE DISCUSSION...1225 PM CST
THE IMPRESSIVE AXIS OF HEAVY SNOW CONTINUES TO PIVOT AROUND THE
CLIPPER CIRCULATION CENTER FROM THE DEKALB AREA SOUTHEAST ALL THE
WAY TO DANVILLE AND WEST LAFAYETTE...WITH A PARENT MESOSCALE
CIRCULATION EVIDENT ON THE RADAR MOSAIC IN LASALLE COUNTY. THIS
SNOWFALL BAND HAS HAD RATES OF 2 IN/HR BASED ON NUMEROUS REPORTS
AND RADAR AND VISIBILITY TRENDS INDICATE THIS CONTINUES. THIS
REMAINS DRIVEN BY STRONG MOIST ISENTROPIC ASCENT AND
CONVERGENCE...ROBUST VORTICITY ADVECTION IN THE MID- LEVELS...AND
WELL-DEFINED FRONTONGENSIS BENEATH AN UNSTABLE LAYER. THIS APPEARS
TO BE CONDITIONALLY SYMMETRIC INSTABILITY AND EVEN POSSIBLY
UPRIGHT INSTABILITY THAT IS REALLY SUPPORTING THE HEAVIEST
SNOWFALL. ALL OF THESE ELEMENTS WILL CONTINUE TO FORCE REGULAR
BANDED SNOW...WITH THE HEAVIEST AXIS MOVING INTO THE WESTERN AND
SOUTHERN CHICAGO METRO AREA AND LIKELY PERSISTING THROUGH 3 PM OR
SO...PROVIDING A QUICK COUPLE INCHES AT LEAST. EVEN AS FAR NORTH
AS THE WI STATE LINE...THERE HAVE BEEN TRANSIENT RADAR
ENHANCEMENTS REFLECTING BANDING TO THE NORTH OF THE MAIN HEAVY
AXIS. VISIBILITY HAS DROPPED TO ONE HALF TO THREE QUARTERS OF A
MILE IN THESE AT TIMES.
AFTER 4-5 PM OR SO...THE HEAVIEST RATES SHOULD BE SHIFTING EAST
WITH THE WARM AIR ADVECTION...AND SNOW WILL BE FORCED MORE BY THE
700MB TROUGH MOVING OVERHEAD.
NO SIGNIFICANT CHANGES MADE TO THE WINTER WEATHER ADVISORY OR
FORECAST SNOW FALL AMOUNTS GOING INTO THIS AFTERNOON. THERE WILL
LIKELY BE SOME ISOLATED AREAS AROUND SIX INCHES...NAMELY WESTERN
LEE AND LASALLE COUNTIES WHICH ALREADY HAD A HEAVY BOUT...AND WILL
REMAIN IN A FAVORED CORRIDOR FOR SNOW AS THE CLIPPER PIVOTS TO THE
SOUTHWEST OF THE CWA BEFORE SHIFTING EAST.
WINDS HAVE ALSO PICKED UP A LITTLE MORE IN THE SOUTHEAST CWA AS
THE LOW QUICKLY APPROACHES. THERE PROBABILITY IS SOME BLOWING
SNOW IN RESPONSE WITHIN OPEN AREAS.
&&
.DISCUSSION...
228 PM CST
REST OF TODAY...
SURFACE LOW IS DIVING SOUTHEAST INTO WEST CENTRAL ILLINOIS THIS
AFTERNOON WITH A NARROW BAND OF MODERATE TO HEAVY SNOW STRETCHING
ACROSS NORTH CENTRAL ILLINOIS INTO NORTHWEST INDIANA. SYSTEM HAS
BEEN FAIRLY WELL BEHAVED SO FAR WITH REPORTS OF AROUND 3-4 INCHES IN
THE AREAS THAT HAVE SEEN THE MOST SNOW THUS FAR. DECENT PACKING OF
THE PRESSURE IS NOTED ON THE 280-285K THETA SURFACES...WITH THE BEST
ASCENT PROGGED TO GRADUALLY SHIFT SOUTHEAST OUT OF THE CWA BY MID
EVENING. RAP H7 F-GEN SEEMS TO INITIALIZE NICELY...LINING UP WELL
WITH RADAR AND STRETCHING FROM THE SOUTH SUBURBS INTO NORTHWEST
INDIANA...AND PIVOTING TO THE EAST OUT OF THE AREA. THE RAP DOES
PICK UP ON F-GEN RESTRENGTHENING THIS EVENING OVER A SIMILAR AREA
AND GRADUALLY SINKING SOUTH ACROSS THE REMAINDER OF THE CWA BY LATE
THIS EVENING. WITH THIS IN MIND...DID SLOW DOWN THE TIMING OF SNOW
ENDING THIS EVENING IN THE GRIDS BY A FEW HOURS.
TONIGHT THROUGH SUNDAY...
THE POTENT UPPER WAVE THAT IMPACTED THE AREA TODAY WILL DEPART
ACROSS THE OHIO VALLEY THIS EVENING AND TONIGHT WITH MID/UPPER
RIDGING BUILDING INTO THE UPPER MIDWEST AND WESTERN LAKES REGION.
STRONG SFC PRESSURE RISES WILL MOVE IN BEHIND THE QUICKLY DEPARTING
LOW AND IS EXPECTED TO LEAD TO BREEZY CONDITIONS THIS
EVENING...MAINLY SOUTH OF I-80. FAIRLY STRONG HEIGHT RISES ALOFT
WILL ALSO OVERSPREAD THE AREA...PERSISTING THROUGH THE DAY SUNDAY
AND SHOULD PROVIDE A BRIEF RESPITE IN THE PRECIPITATION. ONCE THE
SURFACE/LOW LEVEL RIDGE AXIS PASSES OVER THE AREA LATE
TONIGHT...WINDS WILL BACK TO THE SOUTHWEST AND WARMER AIR WILL
ADVECT OVERHEAD...WITH H85 TEMPS RISING TO AROUND 2-3C BY SUNDAY
MORNING. SURFACE TEMPERATURES SHOULD REBOUND TO NEAR THE FREEZING
MARK DURING THE DAY SUNDAY...OTHERWISE SHOULD BE A QUIET WEATHER DAY
TOMORROW.
MONDAY THROUGH TUESDAY ...
MAIN CONCERN AS WE HEAD INTO NEXT WEEK WILL BE THE RETURN OF COLD
ARCTIC AIR. WEST COAST RIDGE IS PROGGED TO AMPLIFY OVER THE
WEEKEND...STRETCHING NORTH ACROSS ALASKA WHICH IN COMBINATION WITH A
DEEPENING LOW OVER ONTARIO WILL DISLODGE AIR FROM THE ARCTIC SOUTH
INTO THE NORTHERN LAKES REGION SUNDAY INTO MONDAY. THE LEADING EDGE
OF THIS COLD AIRMASS WILL SINK SOUTH BEHIND A COLD FRONT THAT WILL
PASS SOUTH OVER THE AREA EARLY MONDAY. TEMPERATURES BEHIND THE FRONT
ARE EXPECTED TO BE FALLING THROUGH THE DAY MONDAY. H85 TEMPS ARE
EXPECTED TO FALL TO AROUND -20C AND GENERALLY PERSIST THROUGH THE
END OF THE WEEK. STEEP LOW LEVEL LAPSE RATES DEVELOP BEHIND THE
FRONT AND APPEARS FAVORABLE FOR COLD AIR CU WITH SOME FLURRIES
DEVELOPING IF NOT A FEW SNOW SHOWERS. ACROSS NORTHWEST
INDIANA...WILL ALSO HAVE TO KEEP AN EYE ON THE LAKE EFFECT MACHINE
WHICH WILL BE RAMPING UP...AND APPEARS VERY FAVORABLE TO SEE SOME
SIGNIFICANT SNOW ACCUMULATIONS IN OR NEAR OUR EASTERN COUNTIES.
OVER LAND...LAPSE RATES WEAKEN MONDAY NIGHT AND APPEARS THAT WE
SHOULD BE WELL ENTRENCHED IN THE COLD/DRY AIR TUESDAY LEADING TO
MOST AREAS STAYING DRY OUTSIDE OF THE LAKE EFFECT.
WEDNESDAY THROUGH FRIDAY...
REGION REMAINS UNDER AN ACTIVE NORTHWEST FLOW PATTERN THROUGH THE
END OF NEXT WEEK RESULTING IN SEVERAL PERIODS OF SNOWFALL AS WAVES
ROTATE ACROSS THE AREA. MODELS HAVE BEEN TRENDING TOWARDS A MORE
ROBUST UPPER WAVE DROPPING ACROSS THE REGION MIDWEEK. SHOULD THIS
PAN OUT...MIGHT SEE A BRIEF/MODEST WARMUP AHEAD OF THE SYSTEM...BUT
THEN EVEN COLDER AIR SPILLING BEHIND. BOTH GEM AND ECMWF INDICATE
TEMPS FALLING TO AROUND -24C AT H85 WEDNESDAY. WHILE ITS PROBABLY A
BIT FAR OUT TO START TALKING LOW TRACK AND POTENTIAL SNOW...FOR NOW
AT LEAST MODELS INDICATE THE LOW WILL STAY NORTH OF THE CWA.
TEMPERATURES SHOULD REMAIN WELL BELOW NORMAL WEDNESDAY AND
THURSDAY...AND ARE EXPECTED TO BEGIN TO MODERATE SOME BY FRIDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ACCUMULATING SNOW THIS AFTERNOON WITH LIFR VISBY AND MVFR/IFR
CIGS. TEMPORARY 1/4SM VISBY PROBABLE NEAR OR OVER MDW PRIOR TO
22Z.
* SE WINDS BACKING TO EASTERLY BY LATE AFTERNOON WITH SPEEDS
AROUND 10 KT. WINDS THEN BACKING FAIRLY QUICKLY TO NNW DURING
MID EVE.
* GUSTY SW WINDS ON SUNDAY LATE MORNING INTO AFTERNOON.
//DISCUSSION...UPDATED 20Z...
HEAVY BAND OF SNOW FROM KJOT TO KRZL CONTINUES TO MOVE NORTHEAST
AT 20Z...ALTHOUGH IS VERY SLOWLY MOVING NORTHWARD. THERE STILL
ARE POCKETS OF HIGHER DBZ APPROACHING MDW AND GYY AIRPORTS AND PER
COORDINATION BELIEVE IT IS BEST TO MENTION 1/4SM PROBABLE. SUCH
LOW VISIBILITY HAS BEEN SEEN AT TIMES WITH ECHOES OF THIS
MAGNITUDE.
PREV DISCUSSION...UPDATED 18Z...
SNOW HAS SPREAD OVER THE TAF SITES AND WILL CONTINUE THROUGH THE
AFTERNOON. THE HEAVIEST SNOW WILL REMAIN TO THE SOUTH OF THE TAF
SITES...HOWEVER RADAR AND METEOROLOGICAL ANALYSIS INDICATE THAT
POCKETS OF HEAVIER SNOW EXTEND NORTH FROM THERE WITH 1/2-3/4SM AT
TIMES NEAR OR AT TAF SITES...WITH ACCOMPANYING TEMPORARY SNOWFALL
RATES OF ONE INCH PER HOUR OR SLIGHTLY HIGHER. WINDS WILL CONTINUE
TO BACK TOWARD EASTERLY BY SUNSET AS THE SYSTEM LOW PRESSURE
PASSES TO THE SOUTH. THESE WINDS WILL THEN BACK QUICKLY TO THE
NORTHWEST BY MID EVE OR SO. SPEEDS WILL BE ON THE INCREASE QUICKLY
ON SUNDAY AS THE PRESSURE GRADIENT TIGHTENS. ANY LINGERING LOW
CLOUDS FROM LATE TONIGHT SHOULD DISSIPATE QUICKLY ON SUNDAY
MORNING.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW-MEDIUM IN VISIBILITY...INCLUDING 1/4SM AT MDW.
* MEDIUM-HIGH IN SNOW DURATION AND LOWEST CIGS.
* LOW-MEDIUM IN TOTAL SNOW ACCUMULATION OF 1-2.5 INCHES.
* HIGH IN WINDS THROUGH 01Z...MEDIUM AFTER.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MAINLY VFR. A FEW FLURRIES NORTH OF ORD/MDW.
MONDAY...SLGT CHC OF SNOW SHOWERS.
TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...PERIODIC CHANCES FOR SNOW SHOWERS AND MVFR.
OTHERWISE VFR.
MTF
&&
.MARINE...
307 PM CST
NO CHANGES WERE MADE TO THE ONGOING HEADLINES AS GALES ARE STILL
EXPECTED.
THE LOW IS OVER THE MID MISSISSIPPI RIVER VALLEY AND WHILE IT IS
FILLING SLOWER THAN PREVIOUSLY EXPECTED...IT IS STILL EXPECTED TO
FILL AS MOVES ACROSS SOUTHERN IL. A SECOND LOW IS MOVING INTO
NORTHERN QUEBEC AND ITS COLD FRONT WILL SINK SOUTH DOWN THE LAKE
SUNDAY AND SUNDAY NIGHT. AS THE GRADIENT TIGHTENS
TONIGHT...SOUTHWEST WINDS INCREASE TO GALES OVER THE NORTHERN HALF
TO THE LAKE. WINDS TURN WEST ACROSS THE LAKE AND INCREASE TO LOW END
GALES BY SUNDAY MORNING. WINDS DIMINISH SUNDAY AFTERNOON...AND MAY
COME DOWN BEFORE THE END OF THE GALE WARNING.
WINDS THEN TURN NORTH BEHIND THE FRONT SUNDAY NIGHT AND REMAIN AT 20
TO 25 KT...POSSIBLY UP TO 30 KT AT TIMES...THROUGH MONDAY NIGHT.
HIGH PRESSURE MOVES OVER THE UPPER PLAINS MONDAY NIGHT AND SLIDES
SOUTHEAST REACHING THE SE US WEDNESDAY. WINDS DIMINISH TUESDAY AND
BECOME WEST. GUIDANCE DIFFERS IN REGARDS TO THE PATTERN MID NEXT
WEEK. THE ECMWF FEATURES A DEEP LOW OVER THE LAKE WHILE THE GFS HAS
A WEAK SURFACE TROUGH. BOTH DO FEATURE A HIGH MOVING OVER THE
PLAINS. SO HAVE WINDS BECOMING NORTHWEST AND/OR NORTH WEDNESDAY
NIGHT...AND IF THE LOW IS DEEPER...WINDS COULD BE STRONGER. AS THE
HIGH PASSES TO THE SOUTH LATE NEXT WEEK...WINDS WEAKEN AND BECOME
WEST.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019-ILZ020-
ILZ021-ILZ022-ILZ032 UNTIL 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 PM
SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 PM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SUNDAY TO 3 PM
SUNDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...MIDNIGHT SUNDAY TO 3 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...3 AM SUNDAY TO 10
PM SUNDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...9 AM SUNDAY TO 4 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM SUNDAY TO 9
AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
230 PM CST SAT JAN 18 2014
.MESOSCALE DISCUSSION...
1225 PM CST
THE IMPRESSIVE AXIS OF HEAVY SNOW CONTINUES TO PIVOT AROUND THE
CLIPPER CIRCULATION CENTER FROM THE DEKALB AREA SOUTHEAST ALL THE
WAY TO DANVILLE AND WEST LAFAYETTE...WITH A PARENT MESOSCALE
CIRCULATION EVIDENT ON THE RADAR MOSAIC IN LASALLE COUNTY. THIS
SNOWFALL BAND HAS HAD RATES OF 2 IN/HR BASED ON NUMEROUS REPORTS
AND RADAR AND VISIBILITY TRENDS INDICATE THIS CONTINUES. THIS
REMAINS DRIVEN BY STRONG MOIST ISENTROPIC ASCENT AND
CONVERGENCE...ROBUST VORTICITY ADVECTION IN THE MID- LEVELS...AND
WELL-DEFINED FRONTONGENSIS BENEATH AN UNSTABLE LAYER. THIS APPEARS
TO BE CONDITIONALLY SYMMETRIC INSTABILITY AND EVEN POSSIBLY
UPRIGHT INSTABILITY THAT IS REALLY SUPPORTING THE HEAVIEST
SNOWFALL. ALL OF THESE ELEMENTS WILL CONTINUE TO FORCE REGULAR
BANDED SNOW...WITH THE HEAVIEST AXIS MOVING INTO THE WESTERN AND
SOUTHERN CHICAGO METRO AREA AND LIKELY PERSISTING THROUGH 3 PM OR
SO...PROVIDING A QUICK COUPLE INCHES AT LEAST. EVEN AS FAR NORTH
AS THE WI STATE LINE...THERE HAVE BEEN TRANSIENT RADAR
ENHANCEMENTS REFLECTING BANDING TO THE NORTH OF THE MAIN HEAVY
AXIS. VISIBILITY HAS DROPPED TO ONE HALF TO THREE QUARTERS OF A
MILE IN THESE AT TIMES.
AFTER 4-5 PM OR SO...THE HEAVIEST RATES SHOULD BE SHIFTING EAST
WITH THE WARM AIR ADVECTION...AND SNOW WILL BE FORCED MORE BY THE
700MB TROUGH MOVING OVERHEAD.
NO SIGNIFICANT CHANGES MADE TO THE WINTER WEATHER ADVISORY OR
FORECAST SNOW FALL AMOUNTS GOING INTO THIS AFTERNOON. THERE WILL
LIKELY BE SOME ISOLATED AREAS AROUND SIX INCHES...NAMELY WESTERN
LEE AND LASALLE COUNTIES WHICH ALREADY HAD A HEAVY BOUT...AND WILL
REMAIN IN A FAVORED CORRIDOR FOR SNOW AS THE CLIPPER PIVOTS TO THE
SOUTHWEST OF THE CWA BEFORE SHIFTING EAST.
WINDS HAVE ALSO PICKED UP A LITTLE MORE IN THE SOUTHEAST CWA AS
THE LOW QUICKLY APPROACHES. THERE PROBABILITY IS SOME BLOWING
SNOW IN RESPONSE WITHIN OPEN AREAS.
&&
.DISCUSSION...
228 PM CST
REST OF TODAY...
SURFACE LOW IS DIVING SOUTHEAST INTO WEST CENTRAL ILLINOIS THIS
AFTERNOON WITH A NARROW BAND OF MODERATE TO HEAVY SNOW STRETCHING
ACROSS NORTH CENTRAL ILLINOIS INTO NORTHWEST INDIANA. SYSTEM HAS
BEEN FAIRLY WELL BEHAVED SO FAR WITH REPORTS OF AROUND 3-4 INCHES IN
THE AREAS THAT HAVE SEEN THE MOST SNOW THUS FAR. DECENT PACKING OF
THE PRESSURE IS NOTED ON THE 280-285K THETA SURFACES...WITH THE BEST
ASCENT PROGGED TO GRADUALLY SHIFT SOUTHEAST OUT OF THE CWA BY MID
EVENING. RAP H7 F-GEN SEEMS TO INITIALIZE NICELY...LINING UP WELL
WITH RADAR AND STRETCHING FROM THE SOUTH SUBURBS INTO NORTHWEST
INDIANA...AND PIVOTING TO THE EAST OUT OF THE AREA. THE RAP DOES
PICK UP ON F-GEN RESTRENGTHENING THIS EVENING OVER A SIMILAR AREA
AND GRADUALLY SINKING SOUTH ACROSS THE REMAINDER OF THE CWA BY LATE
THIS EVENING. WITH THIS IN MIND...DID SLOW DOWN THE TIMING OF SNOW
ENDING THIS EVENING IN THE GRIDS BY A FEW HOURS.
TONIGHT THROUGH SUNDAY...
THE POTENT UPPER WAVE THAT IMPACTED THE AREA TODAY WILL DEPART
ACROSS THE OHIO VALLEY THIS EVENING AND TONIGHT WITH MID/UPPER
RIDGING BUILDING INTO THE UPPER MIDWEST AND WESTERN LAKES REGION.
STRONG SFC PRESSURE RISES WILL MOVE IN BEHIND THE QUICKLY DEPARTING
LOW AND IS EXPECTED TO LEAD TO BREEZY CONDITIONS THIS
EVENING...MAINLY SOUTH OF I-80. FAIRLY STRONG HEIGHT RISES ALOFT
WILL ALSO OVERSPREAD THE AREA...PERSISTING THROUGH THE DAY SUNDAY
AND SHOULD PROVIDE A BRIEF RESPITE IN THE PRECIPITATION. ONCE THE
SURFACE/LOW LEVEL RIDGE AXIS PASSES OVER THE AREA LATE
TONIGHT...WINDS WILL BACK TO THE SOUTHWEST AND WARMER AIR WILL
ADVECT OVERHEAD...WITH H85 TEMPS RISING TO AROUND 2-3C BY SUNDAY
MORNING. SURFACE TEMPERATURES SHOULD REBOUND TO NEAR THE FREEZING
MARK DURING THE DAY SUNDAY...OTHERWISE SHOULD BE A QUIET WEATHER DAY
TOMORROW.
MONDAY THROUGH TUESDAY ...
MAIN CONCERN AS WE HEAD INTO NEXT WEEK WILL BE THE RETURN OF COLD
ARCTIC AIR. WEST COAST RIDGE IS PROGGED TO AMPLIFY OVER THE
WEEKEND...STRETCHING NORTH ACROSS ALASKA WHICH IN COMBINATION WITH A
DEEPENING LOW OVER ONTARIO WILL DISLODGE AIR FROM THE ARCTIC SOUTH
INTO THE NORTHERN LAKES REGION SUNDAY INTO MONDAY. THE LEADING EDGE
OF THIS COLD AIRMASS WILL SINK SOUTH BEHIND A COLD FRONT THAT WILL
PASS SOUTH OVER THE AREA EARLY MONDAY. TEMPERATURES BEHIND THE FRONT
ARE EXPECTED TO BE FALLING THROUGH THE DAY MONDAY. H85 TEMPS ARE
EXPECTED TO FALL TO AROUND -20C AND GENERALLY PERSIST THROUGH THE
END OF THE WEEK. STEEP LOW LEVEL LAPSE RATES DEVELOP BEHIND THE
FRONT AND APPEARS FAVORABLE FOR COLD AIR CU WITH SOME FLURRIES
DEVELOPING IF NOT A FEW SNOW SHOWERS. ACROSS NORTHWEST
INDIANA...WILL ALSO HAVE TO KEEP AN EYE ON THE LAKE EFFECT MACHINE
WHICH WILL BE RAMPING UP...AND APPEARS VERY FAVORABLE TO SEE SOME
SIGNIFICANT SNOW ACCUMULATIONS IN OR NEAR OUR EASTERN COUNTIES.
OVER LAND...LAPSE RATES WEAKEN MONDAY NIGHT AND APPEARS THAT WE
SHOULD BE WELL ENTRENCHED IN THE COLD/DRY AIR TUESDAY LEADING TO
MOST AREAS STAYING DRY OUTSIDE OF THE LAKE EFFECT.
WEDNESDAY THROUGH FRIDAY...
REGION REMAINS UNDER AN ACTIVE NORTHWEST FLOW PATTERN THROUGH THE
END OF NEXT WEEK RESULTING IN SEVERAL PERIODS OF SNOWFALL AS WAVES
ROTATE ACROSS THE AREA. MODELS HAVE BEEN TRENDING TOWARDS A MORE
ROBUST UPPER WAVE DROPPING ACROSS THE REGION MIDWEEK. SHOULD THIS
PAN OUT...MIGHT SEE A BRIEF/MODEST WARMUP AHEAD OF THE SYSTEM...BUT
THEN EVEN COLDER AIR SPILLING BEHIND. BOTH GEM AND ECMWF INDICATE
TEMPS FALLING TO AROUND -24C AT H85 WEDNESDAY. WHILE ITS PROBABLY A
BIT FAR OUT TO START TALKING LOW TRACK AND POTENTIAL SNOW...FOR NOW
AT LEAST MODELS INDICATE THE LOW WILL STAY NORTH OF THE CWA.
TEMPERATURES SHOULD REMAIN WELL BELOW NORMAL WEDNESDAY AND
THURSDAY...AND ARE EXPECTED TO BEGIN TO MODERATE SOME BY FRIDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* ACCUMULATING SNOW THIS AFTERNOON WITH LIFR VISBY AND MVFR/IFR
CIGS. TEMPORARY 1/4SM VISBY PROBABLE NEAR OR OVER MDW PRIOR TO
22Z.
* SE WINDS BACKING TO EASTERLY BY LATE AFTERNOON WITH SPEEDS
AROUND 10 KT. WINDS THEN BACKING FAIRLY QUICKLY TO NNW DURING
MID EVE.
* GUSTY SW WINDS ON SUNDAY LATE MORNING INTO AFTERNOON.
//DISCUSSION...UPDATED 20Z...
HEAVY BAND OF SNOW FROM KJOT TO KRZL CONTINUES TO MOVE NORTHEAST
AT 20Z...ALTHOUGH IS VERY SLOWLY MOVING NORTHWARD. THERE STILL
ARE POCKETS OF HIGHER DBZ APPROACHING MDW AND GYY AIRPORTS AND PER
COORDINATION BELIEVE IT IS BEST TO MENTION 1/4SM PROBABLE. SUCH
LOW VISIBILITY HAS BEEN SEEN AT TIMES WITH ECHOES OF THIS
MAGNITUDE.
PREV DISCUSSION...UPDATED 18Z...
SNOW HAS SPREAD OVER THE TAF SITES AND WILL CONTINUE THROUGH THE
AFTERNOON. THE HEAVIEST SNOW WILL REMAIN TO THE SOUTH OF THE TAF
SITES...HOWEVER RADAR AND METEOROLOGICAL ANALYSIS INDICATE THAT
POCKETS OF HEAVIER SNOW EXTEND NORTH FROM THERE WITH 1/2-3/4SM AT
TIMES NEAR OR AT TAF SITES...WITH ACCOMPANYING TEMPORARY SNOWFALL
RATES OF ONE INCH PER HOUR OR SLIGHTLY HIGHER. WINDS WILL CONTINUE
TO BACK TOWARD EASTERLY BY SUNSET AS THE SYSTEM LOW PRESSURE
PASSES TO THE SOUTH. THESE WINDS WILL THEN BACK QUICKLY TO THE
NORTHWEST BY MID EVE OR SO. SPEEDS WILL BE ON THE INCREASE QUICKLY
ON SUNDAY AS THE PRESSURE GRADIENT TIGHTENS. ANY LINGERING LOW
CLOUDS FROM LATE TONIGHT SHOULD DISSIPATE QUICKLY ON SUNDAY
MORNING.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW-MEDIUM IN VISIBILITY...INCLUDING 1/4SM AT MDW.
* MEDIUM-HIGH IN SNOW DURATION AND LOWEST CIGS.
* LOW-MEDIUM IN TOTAL SNOW ACCUMULATION OF 1-2.5 INCHES.
* HIGH IN WINDS THROUGH 01Z...MEDIUM AFTER.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MAINLY VFR. A FEW FLURRIES NORTH OF ORD/MDW.
MONDAY...SLGT CHC OF SNOW SHOWERS.
TUESDAY...MAINLY VFR.
WEDNESDAY-FRIDAY...PERIODIC CHANCES FOR SNOW SHOWERS AND MVFR.
OTHERWISE VFR.
MTF
&&
.MARINE...
305 AM CST
FAST MOVING CLIPPER SYSTEM...HAS PUSHED SOUTHEAST FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS EARLY THIS MORNING. DOWNSTREAM OF
THIS SYSTEM ACROSS LAKE MICHIGAN HAS BEEN A WEAK SURFACE
RIDGE...WHICH HAS DIMINISHED WINDS TO 10-15KT EARLY THIS MORNING.
THIS WEAK RIDGE OF HIGH PRESSURE WILL QUICKLY SHIFT EAST AHEAD OF
THE LOW PRESSURE...AND ALLOW WINDS TO TURN SOUTHERLY ACROSS THE
CENTRAL/SOUTHERN PORTIONS OF THE LAKE. AS THE LOW ARRIVES FROM THE
NORTHWEST...GUIDANCE CONTINUES TO INDICATE A TIGHTENING GRADIENT.
THIS WILL BE REFLECTED IN WINDS QUICKLY INCREASING TO 20-25KT THIS
EVENING...THEN FURTHER INCREASING TO WEST GALES TO 35 KT FOR THE
NORTHERN HALF OF THE LAKE LATE TONIGHT. THE GRADIENT WILL
EVENTUALLY WORK SOUTH ACROSS THE SOUTHERN PORTIONS OF THE LAKE AND
INCLUDE THE NORTHWEST INDIANA NEARSHORE WATERS WITH GALES TO 35 KT
DEVELOPING EARLY SUNDAY MORNING. GALE CONDITIONS WILL LIKELY
PERSIST THROUGH SUNDAY AFTERNOON...THEN DIMINISH WITH THE PASSAGE
OF A FRONTAL BOUNDARY AND SHIFT TO THE NORTHWEST LATE SUNDAY
NIGHT. WAVES WILL LIKELY REMAIN HAZARDOUS FOR THE INDIANA
NEARSHORE WATERS THROUGH SUNDAY NIGHT...POSSIBLY INTO MONDAY
MORNING.
THEN ANOTHER AREA OF LOW PRESSURE SLIDES SOUTHEAST ACROSS THE LAKE
MONDAY INTO TUESDAY. A BROAD RIDGE OF HIGH PRESSURE SLIDES SOUTH
INTO THE NORTHERN PLAINS TUESDAY...WHICH INTRODUCES ANOTHER TIGHT
PRESSURE GRADIENT AND POSSIBLY PUSH WINDS TO 30KT TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. THIS WILL ALLOW WAVES TO BUILD FOR THE
SOUTHERN HALF OF LAKE MICHIGAN TUE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019-ILZ020-
ILZ021-ILZ022-ILZ032 UNTIL 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039 UNTIL 9 PM
SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 PM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SUNDAY TO 3 PM
SUNDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...MIDNIGHT SUNDAY TO 3 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...3 AM SUNDAY TO 10
PM SUNDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...9 AM SUNDAY TO 4 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM SUNDAY TO 9
AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
316 AM CST SAT JAN 18 2014
.DISCUSSION...
640 PM CST
EARLY EVENING UPDATE...
MINOR CHANGES TO FORECAST GRIDS/ZFP TO RAISE POPS ACROSS NORTHEAST
IL THROUGH EARLY EVENING...AS AREA OF LIGHT SNOW CONTINUES TO PIVOT
SLOWLY SOUTHEAST ACROSS THE REGION.
RECENT AMDAR ASCENT SOUNDING FROM KMDW CONTINUES TO DEPICT SATURATED
COLUMN FROM 900 MB THROUGH AROUND 775 MB...WITH ENTIRE MOIST LAYER
LOCATED WITHIN THE DENDRITIC GROWTH SWEET SPOT -15C TO -17C. WEAK
SHEARED MID-LEVEL VORT MAX ROTATING AROUND BACK SIDE OF LARGER SCALE
UPPER TROUGH AXIS IS PROVIDING WEAK BUT PERSISTENT FORCING
SUFFICIENT TO PRODUCE LIGHT SNOW WITH SOME MINOR ACCUMULATIONS.
TRENDS FROM SHORT TERM RAP GUIDANCE CONTINUES TO WEAKEN AND MOVE THE
VORT AXIS OFF TO THE SOUTHEAST THROUGH MID-EVENING...ALLOWING A
DECREASE IN INTENSITY OF THE LIGHT SNOW TO SCATTERED FLURRIES BY THE
LATE EVENING HOURS. THIS IS PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST TRENDS...THOUGH HAVE INCREASED POPS IN NEXT FEW HOURS TO
CATEGORICAL ACROSS NORTHEAST IL WHERE LIGHT SNOW CURRENTLY PRODUCING
SOME LIGHT ACCUMS. FLUFFY NATURE OF SOME OF THE DENDRITES MAY ALLOW
UP TO A HALF INCH OF ADDITIONAL ACCUMULATION IN SOME SPOTS ACROSS
THE CHICAGO METRO AREA...COINCIDENT WITH SOME OF THE STRONG 20+ DBZ
RADAR RETURNS. DRIER AIR FILTERING IN FROM THE WEST MAY ALLOW SOME
PARTIAL CLEARING ACROSS NORTH CENTRAL IL...BEFORE RAPIDLY ADVANCING
CIRRUS SHIELD SPREADS IN AHEAD OF TOMORROWS CLIPPER.
RATZER
//PREV DISCUSSION...
301 PM CST
REST OF TODAY AND TONIGHT...
AREA OF LIGHT SNOW CONTINUES TO PIVOT ACROSS NORTHERN ILLINOIS THIS
AFTERNOON ASSOCIATED WITH A SHEARED VORT LOBE ROTATING AROUND THE
MAIN UPPER TROUGH AXIS WHICH HAS SHIFTED EAST OF THE AREA.
SMALLER SCALE FORCING IS EMBEDDED WITHIN LARGER SCALE
SUBSIDENCE AS AN H5 RIDGE BUILDS OVER THE AREA OVERNIGHT. UPSTREAM
VSBY GENERALLY IN THE 2-5SM RANGE PERIODICALLY DROPPING
BELOW...INDICATING THAT MOST OF THE SNOW IS PRETTY LIGHT. EXPECT THE
AREA TO CONTINUE TO PIVOT EAST ACROSS NORTHERN ILLINOIS POSSIBLY
DROPPING A DUSTING OF SNOW WITH FLURRIES LINGERING INTO THE
EVENING.
SATURDAY...
ANOTHER ROUND OF SNOW IS EXPECTED ON SATURDAY WITH MODEST
ACCUMULATION APPEARING LIKELY. A 130KT JET DIGGING INTO THE UPPER
MIDWEST WITH A POTENT H5 VORT MAX AT THE NOSE OF THE JET WILL RACE
SOUTHEAST ACROSS IOWA INTO CENTRAL ILLINOIS SATURDAY AFTERNOON.
TAKING A LOOK FOR THE HOOK ON THE PV1.5 SURFACE...A TROP FOLD
EXTENDS DOWN TO ALMOST 600 MB SATURDAY AFTERNOON...WITH THE BEST
PRESSURE ADVECTION AND ASCENT FOCUSED ACROSS CENTRAL ILLINOIS
INCLUDING PORTIONS OF THE FAR SOUTHERN CWA WHERE THE SURFACE LOW IS
EXPECTED TO TRACK. ISENTROPIC SURFACES SIMILARLY INDICATE TIGHTEST
PACKING IN THE FAR WEST/SOUTH CWA WITH THE BEST FOCUSED ASCENT
AND RESULTING PRECIP AXIS EXTENDING FROM ROUGHLY DIXON ILLINOIS TO
FOWLER INDIANA. IN ADDITION...CROSS SECTIONS SHOW AN AREA OF
STRONGER F-GEN TRANSLATING ALONG THAT SAME LINE WITH NEGATIVE
SATURATED EPV RIGHT ON TOP OF THE LAYER OF BEST F-GEN...INDICATING
THE POTENTIAL FOR A DEEP VERTICAL RESPONSE AND BANDED SNOWFALL WITH
UNEVEN DISTRIBUTION OF THE SNOW TOTALS. UTILIZED A NAM/GFS QPF
BLEND FOR THIS PERIOD...AND SLIGHTLY HIGHER THAN AVERAGE SNOW RATIOS
AROUND 15-16:1...CAME UP WITH 3 TO 5 INCHES ALONG AND SOUTH OF THE
DIXON TO FOWLER LINE...WITH 1 TO 3 INCHES TO THE NORTH. THESE
AMOUNTS LINE UP WELL WITH GARCIA METHOD WHICH RESULTS IN ROUGHLY 3-4
INCHES...AND SREF PLUMES. AGAIN...WITH THE POTENTIAL FOR MESOSCALE
BANDING...THERE COULD BE SOME LOCALIZED HIGHER AMOUNTS OF 5 TO 6
INCHES WITHIN THE MAIN PRECIP AXIS ACROSS THE WEST/SOUTH PORTION OF
THE CWA. WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR 3 TO
5 INCHES OF SNOW FOR THE AFFECTED AREAS.
SUNDAY AND MONDAY...
ON SUNDAY BROAD H5 HEIGHT RISES WILL BUILD ACROSS THE AREA WITH
TRANSIENT SURFACE RIDGE PROGRESSING ACROSS THE AREA EARLY IN THE
DAY. WINDS BACK TO THE SOUTHWEST BY SUNDAY AFTERNOON WITH H85
THERMAL GRADIENT LIFTING ACROSS THE AREA...WITH TEMPS APPROACHING
3-4C. SURFACE TEMPS SHOULD PUSH TO OR SLIGHTLY ABOVE THE FREEZING
MARK...TEMPERED SOME BY SATURDAYS SNOWPACK. ANOTHER SHORTWAVE WILL
BRUSH JUST NORTH OF THE AREA SUNDAY NIGHT WITH A COLD FRONT PUSHING
SOUTH ACROSS THE AREA THROUGH THE DAY MONDAY. MOISTURE SOMEWHAT
SHALLOW BEHIND THE FRONT...BUT STEEP LOW LEVEL LAPSE RATES WITH EVEN
SOME UPRIGHT INSTABILITY NOTED ON THE SOUNDINGS INDICATE THE
POTENTIAL FOR AT LEAST SOME FLURRIES IF NOT A FEW SNOW SHOWERS.
DEPENDING ON THE EXACT TIMING OF THE FRONT...COULD SEE TEMPS FALLING
THROUGH THE DAY MONDAY. TAKING A STEP BACK AND LOOKING AT THE BIGGER
PICTURE FOR MONDAY...STRONG RIDGING OVER THE WEST COAST AND ALASKA
THIS WEEKEND WILL HELP DISLODGE AN ARCTIC AIRMASS WHICH WILL SINK
INTO GREAT LAKES MONDAY WITH THE LEADING EDGE REACHING NEAR THE OHIO
VALLEY BY MONDAY EVENING. THE COLDEST AIR AROUND -30C WILL STAY
PRIMARILY OVER THE NORTHERN LAKES REGION BUT MODELS CONTINUE TO SHOW
-20C AIR REACHING INTO ILLINOIS RESULTING IN ANOTHER PERIOD OF
FRIGID CONDITIONS AS WE HEAD INTO NEXT WEEK.
DEUBELBEISS
LONG TERM...MONDAY NIGHT THROUGH THURSDAY...
THE UPPER LEVEL TROUGH REMAINS OVERHEAD WITH SUBSEQUENT TROUGH
AXES PASS OVER THE REGION MONDAY NIGHT AND MID TO LATE NEXT WEEK.
AT THE SURFACE...HIGH PRESSURE BUILDS OVER THE GREAT PLAINS AND
MIDWEST MONDAY NIGHT THROUGH TUESDAY NIGHT. LOW PRESSURE PASSES TO
THE NORTH MID WEEK WITH HIGH PRESSURE BUILDING IN BEHIND IT.
GIVEN THE MODEL DISCREPANCIES REGARDING WHEN THE UPPER LEVEL TROUGH
AXIS/SURFACE LOW WILL PASS THROUGH THE REGION...KEPT POPS IN THE
SLIGHT CHANCE TO CHANCE RANGE MID TO LATE NEXT WEEK. THE ECMWF IS
FASTER AND FEATURES A MUCH STRONGER LOW...BUT WILL RESIST LEANING
TOO MUCH IN ITS DIRECTION.
FOR TEMPS...COLD AIR MOVES IN MONDAY NIGHT WITH 925MB TEMPS FALLING
TO -16 TO -22C. LOWERED MONDAY NIGHT/S LOWS A BIT...BUT ONCE AGAIN
WAITING FOR MODELS TO COME INTO BETTER ALIGNMENT BEFORE MAKING MAJOR
CHANGES. TUESDAY NIGHT LOOKS TO BE THE COLDEST WITH CONTINUED COLD
AIR UPSTAIRS AND A SURFACE HIGH OVERHEAD. LOWS BTWN 0 AND -10F IF
NOT COLDER ARE EXPECTED. BRIEF WAA ON WEDNESDAY WILL LEAD TO HIGH
TEMPS ABOVE 0. TEMPS AROUND ZERO ARE EXPECTED AGAIN WEDNESDAY NIGHT
WITH BELOW NORMAL TEMPS CONTINUING THROUGH LATE NEXT WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CIGS RETURN ARND 15-17Z...AND CONTINUE TO LOWER TO CIGS
ARND 1200FT AGL ARND 18Z.
* LIGHT SNOW/FLURRIES BEGIN ARND 17Z...WITH MODERATE SNOW ARRIVING
CLOSER TO 18-19Z AND LINGERING THRU 20-21Z BEFORE TURNING BACK
TO FLURRIES. PERIOD OF IFR WITH MODERATE SNOWFALL.
* LIGHT WEST WINDS ARND 10KT OVERNIGHT...TURNING SOUTH TO
SOUTHEAST MIDDAY 110-130 DEG. THEN WINDS FLIP TO NORTHWEST
290-310 DEG ARND 23-00Z.
BEACHLER
//DISCUSSION...UPDATED 06Z...
IR IMAGERY EARLY THIS MORNING SHOWS A WEDGE OF SOME CLEARING THAT
HAS TAKEN PLACE BETWEEN THE TWO WEATHER SYSTEMS...AS A RESULT OF
SOME WEAK SURFACE RIDGING. SFC OBS INDICATE WINDS HAVE BEGUN TO
DIMINISH TO ARND 7-9KT FROM THE WEST...HOWEVER JUST WEST OF
NORTHERN IL AIRFIELDS WINDS HAVE BECOME VARIABLE OR BEGINNING TO
TURN SOUTHWESTERLY. MID/UPR LEVEL CLOUDS ARE BEGINNING TO ADVANCE
SOUTHEAST AHEAD OF THE NEXT POTENT CLIPPER...WITH BASES BACK TO
5-6KFT AGL ACROSS FAR NORTHWEST IL. GUIDANCE INDICATES THIS WILL
CONTINUE TO PROGRESSIVELY OVERSPREAD NORTHERN IL/NORTHWEST IN
AIRFIELDS BY DAYBREAK.
GUIDANCE HAS BEEN TRENDING EARLIER WITH THE SNOWFALL THAN
PREVIOUSLY THOUGHT...SO HAVE ADJUSTED THE TIMING OF THE TEMPO AND
SNOW ARRIVAL TO REFLECT THIS. IT APPEARS THE LIGHT SNOW WILL BEGIN
AS FLURRIES/SNOW SHOWERS ARND 17Z. THEN THE BETTER MORE STEADY
SNOWFALL WILL ARRIVE AT ORD/MDW CLOSER TO 18-19Z. AT TIMES THE
SNOW MAY BRING VSBYS DOWN TO ARND 1SM WITH CIGS PUSHING LOWER TO
900FT AGL THROUGH THIS PERIOD OF MODERATE SNOW. THEN ON THE BACK
SIDE OF THE CLIPPER CIGS WILL BE SLOW TO IMPROVE...DESPITE
MOISTURE PEELING SOUTHEAST OF THE AIRFIELDS. SO HAVE HELD ONTO
LOWER CIGS LONGER THRU THE END TIME OF THE CURRENT TAF. WITH THE
CLIPPER WINDS WILL TURN SOUTHERLY TO POSSIBLY SOUTHEASTERLY
MIDDAY...THEN AS THE SYSTEM QUICKLY SLIDES SOUTHEAST OF THE
AIRFIELDS WINDS WILL THEN QUICKLY FLIP TO NORTHWEST. SPEEDS WILL
GENERALLY REMAIN ARND 10KT THROUGHOUT THE PERIOD AS WELL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST.
* HIGH CONFIDENCE IN SNOW AND MEDIUM/HIGH CONFIDENCE IN TIMING OF
SNOW ARRIVAL/END.
* MEDIUM/HIGH CONFIDENCE IN CIGS FORECAST...WITH MEDIUM CONFIDENCE
CIGS DIP TO IFR CONDS DURING MODERATE SNOWFALL TIMING.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...MVFR POSSIBLE...MAINLY SUNDAY NIGHT. GUSTY SW WINDS.
MONDAY...SLGT CHC OF SNOW SHOWERS.
TUESDAY...MAINLY VFR.
WEDNESDAY-THURSDAY...SLGT CHC OF SNOW SHOWERS AND MVFR.
MTF
&&
.MARINE...
305 AM CST
FAST MOVING CLIPPER SYSTEM...HAS PUSHED SOUTHEAST FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS EARLY THIS MORNING. DOWNSTREAM OF
THIS SYSTEM ACROSS LAKE MICHIGAN HAS BEEN A WEAK SURFACE
RIDGE...WHICH HAS DIMINISHED WINDS TO 10-15KT EARLY THIS MORNING.
THIS WEAK RIDGE OF HIGH PRESSURE WILL QUICKLY SHIFT EAST AHEAD OF
THE LOW PRESSURE...AND ALLOW WINDS TO TURN SOUTHERLY ACROSS THE
CENTRAL/SOUTHERN PORTIONS OF THE LAKE. AS THE LOW ARRIVES FROM THE
NORTHWEST...GUIDANCE CONTINUES TO INDICATE A TIGHTENING GRADIENT.
THIS WILL BE REFLECTED IN WINDS QUICKLY INCREASING TO 20-25KT THIS
EVENING...THEN FURTHER INCREASING TO WEST GALES TO 35 KT FOR THE
NORTHERN HALF OF THE LAKE LATE TONIGHT. THE GRADIENT WILL
EVENTUALLY WORK SOUTH ACROSS THE SOUTHERN PORTIONS OF THE LAKE AND
INCLUDE THE NORTHWEST INDIANA NEARSHORE WATERS WITH GALES TO 35 KT
DEVELOPING EARLY SUNDAY MORNING. GALE CONDITIONS WILL LIKELY
PERSIST THROUGH SUNDAY AFTERNOON...THEN DIMINISH WITH THE PASSAGE
OF A FRONTAL BOUNDARY AND SHIFT TO THE NORTHWEST LATE SUNDAY
NIGHT. WAVES WILL LIKELY REMAIN HAZARDOUS FOR THE INDIANA
NEARSHORE WATERS THROUGH SUNDAY NIGHT...POSSIBLY INTO MONDAY
MORNING.
THEN ANOTHER AREA OF LOW PRESSURE SLIDES SOUTHEAST ACROSS THE LAKE
MONDAY INTO TUESDAY. A BROAD RIDGE OF HIGH PRESSURE SLIDES SOUTH
INTO THE NORTHERN PLAINS TUESDAY...WHICH INTRODUCES ANOTHER TIGHT
PRESSURE GRADIENT AND POSSIBLY PUSH WINDS TO 30KT TUESDAY AFTERNOON
THROUGH TUESDAY NIGHT. THIS WILL ALLOW WAVES TO BUILD FOR THE
SOUTHERN HALF OF LAKE MICHIGAN TUE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ019 UNTIL 6 PM
SATURDAY.
WINTER WEATHER ADVISORY...ILZ020-ILZ021-ILZ022-ILZ032...10 AM
SATURDAY TO 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039...10 AM SATURDAY
TO 9 PM SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019...10 AM SATURDAY
TO 9 PM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM SUNDAY TO 3 PM
SUNDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...MIDNIGHT SUNDAY TO 3 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...3 AM SUNDAY TO 10
PM SUNDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...9 AM SUNDAY TO 4 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM SUNDAY TO 9
AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1155 PM CST FRI JAN 17 2014
.DISCUSSION...
640 PM CST
EARLY EVENING UPDATE...
MINOR CHANGES TO FORECAST GRIDS/ZFP TO RAISE POPS ACROSS NORTHEAST
IL THROUGH EARLY EVENING...AS AREA OF LIGHT SNOW CONTINUES TO PIVOT
SLOWLY SOUTHEAST ACROSS THE REGION.
RECENT AMDAR ASCENT SOUNDING FROM KMDW CONTINUES TO DEPICT SATURATED
COLUMN FROM 900 MB THROUGH AROUND 775 MB...WITH ENTIRE MOIST LAYER
LOCATED WITHIN THE DENDRITIC GROWTH SWEET SPOT -15C TO -17C. WEAK
SHEARED MID-LEVEL VORT MAX ROTATING AROUND BACK SIDE OF LARGER SCALE
UPPER TROUGH AXIS IS PROVIDING WEAK BUT PERSISTENT FORCING
SUFFICIENT TO PRODUCE LIGHT SNOW WITH SOME MINOR ACCUMULATIONS.
TRENDS FROM SHORT TERM RAP GUIDANCE CONTINUES TO WEAKEN AND MOVE THE
VORT AXIS OFF TO THE SOUTHEAST THROUGH MID-EVENING...ALLOWING A
DECREASE IN INTENSITY OF THE LIGHT SNOW TO SCATTERED FLURRIES BY THE
LATE EVENING HOURS. THIS IS PRETTY MUCH IN LINE WITH PREVIOUS
FORECAST TRENDS...THOUGH HAVE INCREASED POPS IN NEXT FEW HOURS TO
CATEGORICAL ACROSS NORTHEAST IL WHERE LIGHT SNOW CURRENTLY PRODUCING
SOME LIGHT ACCUMS. FLUFFY NATURE OF SOME OF THE DENDRITES MAY ALLOW
UP TO A HALF INCH OF ADDITIONAL ACCUMULATION IN SOME SPOTS ACROSS
THE CHICAGO METRO AREA...COINCIDENT WITH SOME OF THE STRONG 20+ DBZ
RADAR RETURNS. DRIER AIR FILTERING IN FROM THE WEST MAY ALLOW SOME
PARTIAL CLEARING ACROSS NORTH CENTRAL IL...BEFORE RAPIDLY ADVANCING
CIRRUS SHIELD SPREADS IN AHEAD OF TOMORROWS CLIPPER.
RATZER
//PREV DISCUSSION...
301 PM CST
REST OF TODAY AND TONIGHT...
AREA OF LIGHT SNOW CONTINUES TO PIVOT ACROSS NORTHERN ILLINOIS THIS
AFTERNOON ASSOCIATED WITH A SHEARED VORT LOBE ROTATING AROUND THE
MAIN UPPER TROUGH AXIS WHICH HAS SHIFTED EAST OF THE AREA.
SMALLER SCALE FORCING IS EMBEDDED WITHIN LARGER SCALE
SUBSIDENCE AS AN H5 RIDGE BUILDS OVER THE AREA OVERNIGHT. UPSTREAM
VSBY GENERALLY IN THE 2-5SM RANGE PERIODICALLY DROPPING
BELOW...INDICATING THAT MOST OF THE SNOW IS PRETTY LIGHT. EXPECT THE
AREA TO CONTINUE TO PIVOT EAST ACROSS NORTHERN ILLINOIS POSSIBLY
DROPPING A DUSTING OF SNOW WITH FLURRIES LINGERING INTO THE
EVENING.
SATURDAY...
ANOTHER ROUND OF SNOW IS EXPECTED ON SATURDAY WITH MODEST
ACCUMULATION APPEARING LIKELY. A 130KT JET DIGGING INTO THE UPPER
MIDWEST WITH A POTENT H5 VORT MAX AT THE NOSE OF THE JET WILL RACE
SOUTHEAST ACROSS IOWA INTO CENTRAL ILLINOIS SATURDAY AFTERNOON.
TAKING A LOOK FOR THE HOOK ON THE PV1.5 SURFACE...A TROP FOLD
EXTENDS DOWN TO ALMOST 600 MB SATURDAY AFTERNOON...WITH THE BEST
PRESSURE ADVECTION AND ASCENT FOCUSED ACROSS CENTRAL ILLINOIS
INCLUDING PORTIONS OF THE FAR SOUTHERN CWA WHERE THE SURFACE LOW IS
EXPECTED TO TRACK. ISENTROPIC SURFACES SIMILARLY INDICATE TIGHTEST
PACKING IN THE FAR WEST/SOUTH CWA WITH THE BEST FOCUSED ASCENT
AND RESULTING PRECIP AXIS EXTENDING FROM ROUGHLY DIXON ILLINOIS TO
FOWLER INDIANA. IN ADDITION...CROSS SECTIONS SHOW AN AREA OF
STRONGER F-GEN TRANSLATING ALONG THAT SAME LINE WITH NEGATIVE
SATURATED EPV RIGHT ON TOP OF THE LAYER OF BEST F-GEN...INDICATING
THE POTENTIAL FOR A DEEP VERTICAL RESPONSE AND BANDED SNOWFALL WITH
UNEVEN DISTRIBUTION OF THE SNOW TOTALS. UTILIZED A NAM/GFS QPF
BLEND FOR THIS PERIOD...AND SLIGHTLY HIGHER THAN AVERAGE SNOW RATIOS
AROUND 15-16:1...CAME UP WITH 3 TO 5 INCHES ALONG AND SOUTH OF THE
DIXON TO FOWLER LINE...WITH 1 TO 3 INCHES TO THE NORTH. THESE
AMOUNTS LINE UP WELL WITH GARCIA METHOD WHICH RESULTS IN ROUGHLY 3-4
INCHES...AND SREF PLUMES. AGAIN...WITH THE POTENTIAL FOR MESOSCALE
BANDING...THERE COULD BE SOME LOCALIZED HIGHER AMOUNTS OF 5 TO 6
INCHES WITHIN THE MAIN PRECIP AXIS ACROSS THE WEST/SOUTH PORTION OF
THE CWA. WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR 3 TO
5 INCHES OF SNOW FOR THE AFFECTED AREAS.
SUNDAY AND MONDAY...
ON SUNDAY BROAD H5 HEIGHT RISES WILL BUILD ACROSS THE AREA WITH
TRANSIENT SURFACE RIDGE PROGRESSING ACROSS THE AREA EARLY IN THE
DAY. WINDS BACK TO THE SOUTHWEST BY SUNDAY AFTERNOON WITH H85
THERMAL GRADIENT LIFTING ACROSS THE AREA...WITH TEMPS APPROACHING
3-4C. SURFACE TEMPS SHOULD PUSH TO OR SLIGHTLY ABOVE THE FREEZING
MARK...TEMPERED SOME BY SATURDAYS SNOWPACK. ANOTHER SHORTWAVE WILL
BRUSH JUST NORTH OF THE AREA SUNDAY NIGHT WITH A COLD FRONT PUSHING
SOUTH ACROSS THE AREA THROUGH THE DAY MONDAY. MOISTURE SOMEWHAT
SHALLOW BEHIND THE FRONT...BUT STEEP LOW LEVEL LAPSE RATES WITH EVEN
SOME UPRIGHT INSTABILITY NOTED ON THE SOUNDINGS INDICATE THE
POTENTIAL FOR AT LEAST SOME FLURRIES IF NOT A FEW SNOW SHOWERS.
DEPENDING ON THE EXACT TIMING OF THE FRONT...COULD SEE TEMPS FALLING
THROUGH THE DAY MONDAY. TAKING A STEP BACK AND LOOKING AT THE BIGGER
PICTURE FOR MONDAY...STRONG RIDGING OVER THE WEST COAST AND ALASKA
THIS WEEKEND WILL HELP DISLODGE AN ARCTIC AIRMASS WHICH WILL SINK
INTO GREAT LAKES MONDAY WITH THE LEADING EDGE REACHING NEAR THE OHIO
VALLEY BY MONDAY EVENING. THE COLDEST AIR AROUND -30C WILL STAY
PRIMARILY OVER THE NORTHERN LAKES REGION BUT MODELS CONTINUE TO SHOW
-20C AIR REACHING INTO ILLINOIS RESULTING IN ANOTHER PERIOD OF
FRIGID CONDITIONS AS WE HEAD INTO NEXT WEEK.
DEUBELBEISS
LONG TERM...MONDAY NIGHT THROUGH THURSDAY...
THE UPPER LEVEL TROUGH REMAINS OVERHEAD WITH SUBSEQUENT TROUGH
AXES PASS OVER THE REGION MONDAY NIGHT AND MID TO LATE NEXT WEEK.
AT THE SURFACE...HIGH PRESSURE BUILDS OVER THE GREAT PLAINS AND
MIDWEST MONDAY NIGHT THROUGH TUESDAY NIGHT. LOW PRESSURE PASSES TO
THE NORTH MID WEEK WITH HIGH PRESSURE BUILDING IN BEHIND IT.
GIVEN THE MODEL DISCREPANCIES REGARDING WHEN THE UPPER LEVEL TROUGH
AXIS/SURFACE LOW WILL PASS THROUGH THE REGION...KEPT POPS IN THE
SLIGHT CHANCE TO CHANCE RANGE MID TO LATE NEXT WEEK. THE ECMWF IS
FASTER AND FEATURES A MUCH STRONGER LOW...BUT WILL RESIST LEANING
TOO MUCH IN ITS DIRECTION.
FOR TEMPS...COLD AIR MOVES IN MONDAY NIGHT WITH 925MB TEMPS FALLING
TO -16 TO -22C. LOWERED MONDAY NIGHT/S LOWS A BIT...BUT ONCE AGAIN
WAITING FOR MODELS TO COME INTO BETTER ALIGNMENT BEFORE MAKING MAJOR
CHANGES. TUESDAY NIGHT LOOKS TO BE THE COLDEST WITH CONTINUED COLD
AIR UPSTAIRS AND A SURFACE HIGH OVERHEAD. LOWS BTWN 0 AND -10F IF
NOT COLDER ARE EXPECTED. BRIEF WAA ON WEDNESDAY WILL LEAD TO HIGH
TEMPS ABOVE 0. TEMPS AROUND ZERO ARE EXPECTED AGAIN WEDNESDAY NIGHT
WITH BELOW NORMAL TEMPS CONTINUING THROUGH LATE NEXT WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS RETURN ARND 15-17Z...AND CONTINUE TO LOWER TO CIGS
ARND 1200FT AGL ARND 18Z.
* LIGHT SNOW/FLURRIES BEGIN ARND 17Z...WITH MODERATE SNOW ARRIVING
CLOSER TO 18-19Z AND LINGERING THRU 20-21Z BEFORE TURNING BACK
TO FLURRIES. PERIOD OF IFR WITH MODERATE SNOWFALL.
* LIGHT WEST WINDS ARND 10KT OVERNIGHT...TURNING SOUTH TO
SOUTHEAST MIDDAY 110-130 DEG. THEN WINDS FLIP TO NORTHWEST
290-310 DEG ARND 23-00Z.
BEACHLER
//DISCUSSION...UPDATED 06Z...
IR IMAGERY EARLY THIS MORNING SHOWS A WEDGE OF SOME CLEARING THAT
HAS TAKEN PLACE BETWEEN THE TWO WEATHER SYSTEMS...AS A RESULT OF
SOME WEAK SURFACE RIDGING. SFC OBS INDICATE WINDS HAVE BEGUN TO
DIMINISH TO ARND 7-9KT FROM THE WEST...HOWEVER JUST WEST OF
NORTHERN IL AIRFIELDS WINDS HAVE BECOME VARIABLE OR BEGINNING TO
TURN SOUTHWESTERLY. MID/UPR LEVEL CLOUDS ARE BEGINNING TO ADVANCE
SOUTHEAST AHEAD OF THE NEXT POTENT CLIPPER...WITH BASES BACK TO
5-6KFT AGL ACROSS FAR NORTHWEST IL. GUIDANCE INDICATES THIS WILL
CONTINUE TO PROGRESSIVELY OVERSPREAD NORTHERN IL/NORTHWEST IN
AIRFIELDS BY DAYBREAK.
GUIDANCE HAS BEEN TRENDING EARLIER WITH THE SNOWFALL THAN
PREVIOUSLY THOUGHT...SO HAVE ADJUSTED THE TIMING OF THE TEMPO AND
SNOW ARRIVAL TO REFLECT THIS. IT APPEARS THE LIGHT SNOW WILL BEGIN
AS FLURRIES/SNOW SHOWERS ARND 17Z. THEN THE BETTER MORE STEADY
SNOWFALL WILL ARRIVE AT ORD/MDW CLOSER TO 18-19Z. AT TIMES THE
SNOW MAY BRING VSBYS DOWN TO ARND 1SM WITH CIGS PUSHING LOWER TO
900FT AGL THROUGH THIS PERIOD OF MODERATE SNOW. THEN ON THE BACK
SIDE OF THE CLIPPER CIGS WILL BE SLOW TO IMPROVE...DESPITE
MOISTURE PEELING SOUTHEAST OF THE AIRFIELDS. SO HAVE HELD ONTO
LOWER CIGS LONGER THRU THE END TIME OF THE CURRENT TAF. WITH THE
CLIPPER WINDS WILL TURN SOUTHERLY TO POSSIBLY SOUTHEASTERLY
MIDDAY...THEN AS THE SYSTEM QUICKLY SLIDES SOUTHEAST OF THE
AIRFIELDS WINDS WILL THEN QUICKLY FLIP TO NORTHWEST. SPEEDS WILL
GENERALLY REMAIN ARND 10KT THROUGHOUT THE PERIOD AS WELL.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST.
* HIGH CONFIDENCE IN SNOW AND MEDIUM/HIGH CONFIDENCE IN TIMING OF
SNOW ARRIVAL/END.
* MEDIUM/HIGH CONFIDENCE IN CIGS FORECAST...WITH MEDIUM CONFIDENCE
CIGS DIP TO IFR CONDS DURING MODERATE SNOWFALL TIMING.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...MVFR POSSIBLE...MAINLY SUNDAY NIGHT. GUSTY SW WINDS.
MONDAY...SLGT CHC OF SNOW SHOWERS.
TUESDAY...MAINLY VFR.
WEDNESDAY-THURSDAY...SLGT CHC OF SNOW SHOWERS AND MVFR.
MTF
&&
.MARINE...
300 PM...
A SERIES OF CLIPPER-TYPE SYSTEMS WILL TRACK THROUGH THE GREAT
LAKES REGION OVER THE NEXT SEVERAL DAYS. THIS WILL BRING PERIODS
OF INCREASING AND DECREASING WINDS OF VARIABLE DIRECTION TO THE
LAKE. THE FIRST SYSTEM...OVER LAKE HURON...WILL CONTINUE TO
WEAKEN AS IT MOVES INTO QUEBEC LATE TONIGHT WHILE DRAGGING A WEAK
COLD FRONT SOUTH DOWN THE LAKE TURNING WINDS FROM WESTERLY TO
NORTHWESTERLY. THE NEXT SYSTEM WILL DROP OUT OF NORTHERN ALBERTA
LATE TONIGHT AND DEEPEN AS IT MOVES THROUGH MINNESOTA SATURDAY
MORNING. THIS LOW WILL SLOWLY WEAKEN AS IT TRACKS THROUGH CENTRAL
ILLINOIS SATURDAY AFTERNOON AND DISSIPATE AS IT REACHES THE UPPER
OHIO VALLEY SUNDAY. THIS WILL BE A PERIOD OF RELATIVELY LIGHTER
WINDS OVER THE LAKE...BUT ANOTHER...STRONGER...LOW IS EXPECTED TO
DEVELOP OVER NORTHERN MANITOBA FRIDAY NIGHT AND DROP SOUTHEAST
ACROSS ONTARIO SATURDAY NIGHT WHILE DEEPENING. STRENGTHENING WINDS
AHEAD OF AN ASSOCIATED COLD FRONT MAY APPROACH OR REACH GALE FORCE
SATURDAY NIGHT OR SUNDAY. HIGH PRESSURE WILL THEN BUILD IN BEHIND
THIS FRONT ALLOWING WINDS TO WEAKEN SOMEWHAT AGAIN. THIS PATTERN
SHOULD REPEAT AGAIN EARLY NEXT WEEK AS ANOTHER CLIPPER DROPS OUT
OF CANADA AND TRACKS THROUGH THE UPPER GREAT LAKES,
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ010-ILZ019-ILZ021-ILZ032...6 AM
SATURDAY TO 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ023-ILZ033-ILZ039...10 AM SATURDAY
TO 9 PM SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ019...10 AM SATURDAY TO 9 PM
SATURDAY.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 6 AM SATURDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
325 PM EST SAT JAN 18 2014
.SYNOPSIS...
ISSUED AT 1121 AM EST SAT JAN 18 2014
ANOTHER STORM SYSTEM WILL DROP INTO THE OHIO VALLEY TONIGHT
BRINGING ANOTHER ROUND OF SNOW TO THE REGION THIS AFTERNOON AND
EVENING. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE
UPPER TEENS TO LOWER 20S. LOWS TONIGHT WILL FALL INTO THE TEENS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 320 PM EST SAT JAN 18 2014
TWO CHALLENGES IN THE SHORT TERM: DURATION/INTENSITY/AMOUNT OF SNOW
AND MIN TEMPERATURE TONIGHT/SUNDAY MORNING.
THE CLIPPER SYSTEM IS WELL FORECAST BY THE MODELS THIS AFTERNOON AND
MORNING INITIALIZATIONS WERE NEARLY SPOT ON. LATEST SATELLITE/RADAR
DATA SHOW THE DEEPENING WAVE AND ASSOCIATED WARM SECTOR ASSENT ON
THE EAST AND NORTHEAST AREA IS HOLDING TOGETHER WELL. EXPECT TO SEE
THE LEADING EDGE OF THE SNOW ACROSS THE SOUTHWEST PORTION OF THE CWA
BETWEEN 2-4 PM EST AND THIS WILL SHIFT NORTH AND EAST DURING THE
EVENING. AM CONCERNED THAT THE DRIER AIR IS STARTING TO WRAP AROUND
THE LOW AND THIS SHOULD BE ENOUGH TO CREATE A VERY NARROW
PRECIPITATION BAND. AS MODELS ARE STARTING TO SHOW...THIS WILL BE A
RAPIDLY MOVING SYSTEM AND WHILE THERE ARE HINTS OF FAVORABLE
FRONTOGENETIC FORCING...THE RAPID TRANSITORY NATURE WILL RESULT
GENERAL AREAS OF SNOWFALL WITH EMBEDDED BANDS OF ENHANCED SNOWFALL.
BY MIDNIGHT...THE SYSTEM WILL HAVE BECOME MORE OF AN OPEN WAVE AND
THIS WILL BRING THE SNOWFALL TO A QUICK END FROM WEST TO EAST. MODEL
SOUNDINGS SUGGEST THAT CLOUDS/STRATUS WILL PERSIST OVER MUCH OF THE
AREA...BUT THIS LEADS TO THE SECOND CHALLENGE FOR THE PERIOD. AS THE
TROF OPENS UP AND THE FLOW TURNS MORE WESTERLY...THE POTENTIAL FOR
CLEARING SKIES IS BECOMING MORE LIKELY. AS A RESULT HAVE TRIMMED THE
OVERNIGHT LOWS A FEW DEGREES. THE RUC AND LOCAL WRF ARE BY FAR THE
COOLEST OF THE MODELS AT THIS TIME AND GIVEN THE CLEARING NOTED IN
THE WAKE OF THE SYSTEM...FEEL COMPELLED TO LEAN TOWARD THE COOLER
SOLUTIONS. ONLY A MINOR DOWNWARD ADJUSTMENT MADE.
EXPECT TO SEE A FEW LAKE ENHANCED SNOW SHOWERS DURING THE DAY SUNDAY
WITH FAVORED AREAS NEAR THE SHORELINE AND LIGHT SNOW SHOWERS ALONG
AND NORTH OF US-30.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 PM EST SAT JAN 18 2014
ONCE AGAIN VERY FEW CHANGES NEEDED TO LONG TERM WITH PERSISTENT BUT
ACTIVE PATTERN. LONG WAVE TROUGH REMAINS ANCHORED OVER THE GREAT
LAKES WITH LARGE SCALE RIDGE OVER WEST COAST. DEEP NORTHERLY FLOW
WILL KEEP THE POLAR EXPRESS OF SHORT WAVES ON TRACK WITH SEVERAL
WAVES OVER THE NEXT WEEK. LAKE EFFECT WILL BE ONGOING FOR ABOUT THE
ENTIRE PERIOD BUT BACKING AND VEERING WINDS MAKE BAND ORIENTATION
AND PLACEMENT DIFFICULT AT BEST AT THIS TIME RANGE.
NEXT ARCTIC BOUNDARY STILL SET TO PLUNGE SOUTH ACROSS THE AREA ON
MONDAY. EARLY MORNING HIGHS EXPECTED WITH WINDS BECOMING NORTH
THROUGH THE DAY AND COLD AIR ADVECTION DEEPENING. WILL CONTINUE WITH
LOW CHANCE POPS FOR FLURRIES/LIGHT SNOW SHOWERS AS COLD AIR DEEPENS.
LAKE EFFECT TO LIKELY BE SLOW AND LIGHT AT FIRST BUT AS SECONDARY
FRONT AND COLDER AIR MOVE IN LATER MONDAY AND ESPECIALLY MONDAY
NIGHT INTO TUESDAY...SHOULD SEE THE LAKE EFFECT MACHINE CRANK INTO
FULL GEAR. STILL EXPECT A SIGNIFICANT SINGLE BAND SOMEWHERE BETWEEN
EXTREME SOUTHWEST BERRIEN COUNTY AND PORTER COUNTY IN NW INDIANA.
THIS WILL DEPEND ON STRENGTH OF CONVERGENCE. UPSTREAM CONDITIONING
EXPECTED WITH LONG FETCH AND EXTREME DELTA TS SO SIGNIFICANT
ACCUMULATIONS LIKELY...JUST A QUESTION OF EXACTLY WHERE. STILL NEED
A FEW MORE MODEL ITERATIONS BEFORE HIGHER RESOLUTION GUIDANCE BEGINS
TO PICK UP THESE PERIODS.
REST OF THE WEEK TO SEE A CONTINUATION OF MEANDERING LAKE EFFECT
BANDS AND COLD TEMPS. AS WE HAVE BEEN DISCUSSING...HIGHS IN SINGLE
DIGITS TO TEENS WITH LOWS AROUND ZERO TO 6 BELOW RIGHT NOW. REALLY
EXPECT SOME COLDER READINGS...ESPECIALLY IF WE DECOUPLE AND ARE
CLEAR TUE NIGHT WITH HIGH PRESSURE MOVING THROUGH AND FRESH SNOWPACK.
COULD SEE LOWS BOTTOM OUT IN RURAL AREAS IN THE 10 TO 15 BELOW RANGE
AGAIN IF IDEAL RADIATIONAL CONDITIONS DEVELOP. FOR NOW STAYED ON THE
CONSERVATIVE SIDE OF COLDER BLENDS AROUND 5 BELOW.
YET ANOTHER SHORT WAVE AND REINFORCED SHOT OF COLD AIR AROUND MID
WEEK WILL KEEP CHANCES FOR SNOW SHOWERS GOING. MEDIUM RANGE MODELS
HINT AT ANOTHER POSSIBLE SINGLE BAND BEHIND THIS WAVE. LOWS THU
NIGHT HAVE POTENTIAL TO GO EVEN LOWER THAN CURRENT FCST LOWS IF HIGH
PRESSURE SLIDES IN AND WE DECOUPLE AGAIN.
SLIGHT MODERATION IN MODELS BEING SHOWN FOR DAY 7 BEFORE NEXT POLAR
EXPRESS SHORT WAVE MOVES IN EARLY IN WEEK TWO PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 320 PM EST SAT JAN 18 2014
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1210 PM EST SAT JAN 18 2014
WARM ADVECTION AHEAD OF THE SURFACE LOW ON THE IA/IL BORDER
CONTINUES BRINGING IN ENOUGH MOISTURE AND ISENTROPIC ASSENT TO
PRODUCE STRATUS OVER THE FORECAST AREA. PERIODS OF SCT/BKN STRATUS
WILL PERSIST THROUGH THE FIRST FEW HOURS OF THE FORECAST PERIOD
BEFORE BECOMING MORE UNIFORM IN COVERAGE.
WITH THE LOW TRACKING FROM DVN-EVV-LOZ DURING THE TAF PERIOD
LOWEST CIGS/VSBY WILL BE SOUTH AND WEST OF THE TAF LOCATIONS
OVERNIGHT. STILL EXPECT IFR/POSSIBLE LIFR CONDITIONS AFTER 00Z
AND THIS WILL LAST THROUGH MUCH OF THE REMAINDER OF OVERNIGHT...
WITH IMPROVING CONDITIONS DURING THE LATTER PART OF THE FORECAST
PERIOD.
SOME INDICATIONS THAT AS THE LOW OPENS AND LIFTS NORTHEAST DURING
THE DAY SUNDAY THAT THERE WILL BE A PERIOD OF INCREASED BOUNDARY
LAYER WINDS AND THIS COULD LEAD TO LLWS SITUATION VERY LATE IN THE
FORECAST PERIOD. WILL NOT INCLUDE IN THE TAF AT THIS TIME...BUT
WILL MERIT WATCHING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR INZ025>027-033-
034.
WINTER WEATHER ADVISORY UNTIL 9 PM EST /8 PM CST/ THIS EVENING
FOR INZ012-013-020-022.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR INZ015-
023-024-032.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO MIDNIGHT EST SUNDAY
NIGHT FOR LMZ043-046.
&&
$$
SYNOPSIS...KG
SHORT TERM...LASHLEY
LONG TERM...LEWIS
AVIATION...LEWIS
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1019 AM MST SAT JAN 18 2014
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 230 AM MST SAT JAN 18 2014
TODAY-TONIGHT...STRONG VORT MAX CURRENTLY MOVING TOWARD NORTHERN
IOWA AND NOSE OF 120KT UPPER JET WILL BOTH SLIDE SOUTH/SOUTHEAST
TODAY THEN ACROSS THE EAST COAST TONIGHT. STRONGEST WINDS ALOFT MOVE
INTO THE AREA THIS MORNING AND CONTINUE THROUGH LATE MORNING/EARLY
AFTERNOON BEFORE SLOWLY DECREASING LATE THIS AFTERNOON THROUGH
SUNSET. LOCAL WIND GUST PROGRAM SUGGESTING GUSTS OF 45 TO 57 KTS
ACROSS THE AREA AT 18Z (STRONGEST AT KGLD AND KITR) WITH 40 TO 46
KTS BY 21Z. SO THE QUESTION BECOMES WILL A HIGH WIND WARNING BE
NEEDED.
MET/MAV GUIDANCE ALL SHOWING SUSTAINED WINDS AROUND 30KTS VERY LATE
THIS MORNING WITH A DECREASING TREND THIS AFTERNOON. 06Z RUC SHOWING
GUSTS 50-52KTS FROM COLBY EAST AROUND 18Z WHICH IS OPPOSITE OF WIND
GUST PROGRAM RESULTS. SEEMS TO BE A LACK OF REALLY FAVORABLE OR EVEN
FAVORABLE LOW AND MID LEVEL LAPSE RATES WHICH IS KEEPING ME FROM
UPGRADING TO A HIGH WIND WARNING. EITHER WAY...IT WILL BE WINDY WITH
GUSTS OVER 50 MPH POSSIBLE ALONG WITH SOME BLOWING DUST FROM TIME
TO TIME.
HIGH TEMPERATURES UPPER 40S NORTHEAST WITH LOW 50S ELSEWHERE. LOWS
TONIGHT IN THE 20S.
SUNDAY-SUNDAY NIGHT...WEATHER STORY FOR THIS PERIOD WILL BE MUCH
ABOVE NORMAL HIGH TEMPERATURES WITH 850 TEMPERATURES AND NEARLY ALL
REMAINING GUIDANCE SUPPORTING UPPER 50S TO MID 60S ACROSS THE AREA.
A FEW LOCATIONS SUCH AS MCCOOK AND HILL CITY WILL BE CLOSE IF NOT
REACH RECORD HIGHS FOR THE DAY. SEE CLIMATE SECTION BELOW. LOWS
IN THE LOW TO MID 20S.
MONDAY-MONDAY NIGHT...COLDER TEMPERATURES RETURN AS 850 TEMPERATURES
DROP ABOUT 15-20F FROM SUNDAYS READINGS PUTTING THE AREA BACK INTO
THE 40S FOR HIGHS...CLOSER TO NORMAL FOR MID JANUARY. LOWS MONDAY
UPPER TEENS TO LOW 20S. LOOKS LIKE ANOTHER BREEZY TO WINDY DAY AND
HAVE INCREASED WINDS A BIT AS A RESULT.
NO PRECIPITATION IS EXPECTED THROUGH THE PERIOD.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 230 AM MST SAT JAN 18 2014
A STUBBORN TROUGH/RIDGE PATTERN ACROSS THE CONUS CONTINUES THROUGH
NEXT WEEK. THE RIDGE OVER THE WEST COAST LOOKS TO AMPLIFY TOWARDS
THE END OF THE WEEK WITH H5 HEIGHTS OVER 2 STANDARD DEVIATIONS ABOVE
NORMAL ACROSS THE WESTERN COAST OF CANADA. LOCALLY NORTHWEST FLOW
WILL PERSIST AT UPPER LEVELS WITH A FEW FRONTS OVER THE COURSE OF
THE WEEK. EXTENDED PERIOD WILL BE GENERALLY DRY WITH NEAR SEASONABLE
TEMPS.
TUE AND WED WILL BE MOSTLY SUNNY AND SEASONABLE WITH LIGHT
NORTHWEST WINDS. LATE WEDNESDAY CLOUDS WILL INCREASE AHEAD OF A
BACK DOOR COLD FRONT ASSOCIATED WITH A BROAD AREA OF HIGH PRESSURE
DEVELOPING ACROSS THE NORTHERN PLAINS. COLD CANADIAN AIR WILL
ACCOMPANY THIS SYSTEM...THOUGH LUCKILY THE COLDEST AIR WILL REMAIN
MUCH FARTHER NORTH AND EAST. WHILE THERE IS SOME DISCREPANCIES AS
FAR AS THE COLD GOES...GUIDANCE IS IN FAIRLY GOOD AGREEMENT THAT
WE WILL SEE SOME MID-LEVEL MOISTURE MOVE SOUTH THROUGH THE HIGH
PLAINS AND REACH THE CWA WED NIGHT INTO EARLY THURSDAY. WHILE
LIFT/DYNAMICS ARE NOT VERY GOOD...WOULD NOT BE SURPRISED FOR SEE A
FEW FLURRIES DURING THIS TIME AS WELL...ESPECIALLY IF WE CAN GET
SOME ENHANCEMENT FROM THE RIGHT ENTRANCE REGION OF THE 250MB JET.
THURS WILL BE BREEZY AS THE HIGH PRESSURE OVER THE NORTHERN PLAINS
MOVES EAST. CLOUDS WILL DECREASE LATE IN THE DAY AS WINDS PICK UP
OUT OF THE SOUTH AT 15 TO 20 KTS DUE TO THE STRONG PRESSURE GRADIENT
ACROSS WESTERN KANSAS. FRIDAY WILL BE SEASONABLE...WITH SOME HIGH
CLOUDS LIMITING AFTERNOON TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1016 AM MST SAT JAN 18 2014
VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK. STRONG NORTHWEST
WIND WILL SLOWLY DECREASE BY LATE AFTERNOON AS LOW PRESSURE MOVES
EAST AND THE GRADIENT RELAXES. DO NOT EXPECT ANY VISBILITY REDUCTIONS
DUE TO BLOWING DUST THAT WOULD GO DOWN TO MVFR.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MST SAT JAN 18 2014
TODAY...CURRENT RED FLAG WARNING AREAL COVERAGE LOOKS GOOD AS RH
VALUES AROUND 20 PERCENT COMBINE WITH NORTHWEST WINDS GUSTING UP
TO 50 MPH...POSSIBLY A BIT HIGHER IN SPOTS. AS FAR AS
TIMING...CURRENT START TIME MAY BE A FEW HOURS EARLY.
SUNDAY...RH VALUES FALL INTO THE 20-25 PERCENT RANGE ACROSS THE
AREA DURING THE EARLY AFTERNOON. NORTHWEST WINDS OF 15 TO 20 MPH
ARE POSSIBLE CREATING NEAR CRITICAL FIRE WEATHER CONDITIONS.
SOMETHING TO WATCH.
MONDAY...RH VALUES FALL TOWARD 25 PERCENT BY MID AFTERNOON.
NORTHWEST WINDS OF 20 TO 25 MPH WITH HIGHER GUSTS EXPECTED WHICH
WILL CREATE NEAR CRITICAL FIRE WEATHER CONDITIONS. LATER SHIFTS
WILL NEED TO RE-EVALUATE FOR POSSIBLE FIRE WEATHER HIGHLITE.
&&
.CLIMATE...
ISSUED AT 230 AM MST SAT JAN 18 2014
RECORD AND/OR NEAR RECORD HIGH TEMPERATURES ARE POSSIBLE SUNDAY
JANUARY 19 AT HILL CITY AND MCCOOK. CURRENT RECORDS FOR THE DATE
ARE:
HILL CITY...66 IN 2006 AND PREVIOUS YEARS
MCCOOK......66 IN 1997
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON FOR
KSZ001-002-013>015-027>029-041-042.
WIND ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON FOR
KSZ001>004-013>016-027>029-042.
CO...RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ252>254.
WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ090-091.
NE...RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR NEZ079.
WIND ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON FOR
NEZ079>081.
&&
$$
SHORT TERM...99
LONG TERM...JJM
AVIATION...FS
FIRE WEATHER...99
CLIMATE...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
235 AM MST SAT JAN 18 2014
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 230 AM MST SAT JAN 18 2014
TODAY-TONIGHT...STRONG VORT MAX CURRENTLY MOVING TOWARD NORTHERN
IOWA AND NOSE OF 120KT UPPER JET WILL BOTH SLIDE SOUTH/SOUTHEAST
TODAY THEN ACROSS THE EAST COAST TONIGHT. STRONGEST WINDS ALOFT MOVE
INTO THE AREA THIS MORNING AND CONTINUE THROUGH LATE MORNING/EARLY
AFTERNOON BEFORE SLOWLY DECREASING LATE THIS AFTERNOON THROUGH
SUNSET. LOCAL WIND GUST PROGRAM SUGGESTING GUSTS OF 45 TO 57 KTS
ACROSS THE AREA AT 18Z (STRONGEST AT KGLD AND KITR) WITH 40 TO 46
KTS BY 21Z. SO THE QUESTION BECOMES WILL A HIGH WIND WARNING BE
NEEDED.
MET/MAV GUIDANCE ALL SHOWING SUSTAINED WINDS AROUND 30KTS VERY LATE
THIS MORNING WITH A DECREASING TREND THIS AFTERNOON. 06Z RUC SHOWING
GUSTS 50-52KTS FROM COLBY EAST AROUND 18Z WHICH IS OPPOSITE OF WIND
GUST PROGRAM RESULTS. SEEMS TO BE A LACK OF REALLY FAVORABLE OR EVEN
FAVORABLE LOW AND MID LEVEL LAPSE RATES WHICH IS KEEPING ME FROM
UPGRADING TO A HIGH WIND WARNING. EITHER WAY...IT WILL BE WINDY WITH
GUSTS OVER 50 MPH POSSIBLE ALONG WITH SOME BLOWING DUST FROM TIME
TO TIME.
HIGH TEMPERATURES UPPER 40S NORTHEAST WITH LOW 50S ELSEWHERE. LOWS
TONIGHT IN THE 20S.
SUNDAY-SUNDAY NIGHT...WEATHER STORY FOR THIS PERIOD WILL BE MUCH
ABOVE NORMAL HIGH TEMPERATURES WITH 850 TEMPERATURES AND NEARLY ALL
REMAINING GUIDANCE SUPPORTING UPPER 50S TO MID 60S ACROSS THE AREA.
A FEW LOCATIONS SUCH AS MCCOOK AND HILL CITY WILL BE CLOSE IF NOT
REACH RECORD HIGHS FOR THE DAY. SEE CLIMATE SECTION BELOW. LOWS
IN THE LOW TO MID 20S.
MONDAY-MONDAY NIGHT...COLDER TEMPERATURES RETURN AS 850 TEMPERATURES
DROP ABOUT 15-20F FROM SUNDAYS READINGS PUTTING THE AREA BACK INTO
THE 40S FOR HIGHS...CLOSER TO NORMAL FOR MID JANUARY. LOWS MONDAY
UPPER TEENS TO LOW 20S. LOOKS LIKE ANOTHER BREEZY TO WINDY DAY AND
HAVE INCREASED WINDS A BIT AS A RESULT.
NO PRECIPITATION IS EXPECTED THROUGH THE PERIOD.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 230 AM MST SAT JAN 18 2014
A STUBBORN TROUGH/RIDGE PATTERN ACROSS THE CONUS CONTINUES THROUGH
NEXT WEEK. THE RIDGE OVER THE WEST COAST LOOKS TO AMPLIFY TOWARDS
THE END OF THE WEEK WITH H5 HEIGHTS OVER 2 STANDARD DEVIATIONS ABOVE
NORMAL ACROSS THE WESTERN COAST OF CANADA. LOCALLY NORTHWEST FLOW
WILL PERSIST AT UPPER LEVELS WITH A FEW FRONTS OVER THE COURSE OF
THE WEEK. EXTENDED PERIOD WILL BE GENERALLY DRY WITH NEAR SEASONABLE
TEMPS.
TUE AND WED WILL BE MOSTLY SUNNY AND SEASONABLE WITH LIGHT
NORTHWEST WINDS. LATE WEDNESDAY CLOUDS WILL INCREASE AHEAD OF A
BACK DOOR COLD FRONT ASSOCIATED WITH A BROAD AREA OF HIGH PRESSURE
DEVELOPING ACROSS THE NORTHERN PLAINS. COLD CANADIAN AIR WILL
ACCOMPANY THIS SYSTEM...THOUGH LUCKILY THE COLDEST AIR WILL REMAIN
MUCH FARTHER NORTH AND EAST. WHILE THERE IS SOME DISCREPANCIES AS
FAR AS THE COLD GOES...GUIDANCE IS IN FAIRLY GOOD AGREEMENT THAT
WE WILL SEE SOME MID-LEVEL MOISTURE MOVE SOUTH THROUGH THE HIGH
PLAINS AND REACH THE CWA WED NIGHT INTO EARLY THURSDAY. WHILE
LIFT/DYNAMICS ARE NOT VERY GOOD...WOULD NOT BE SURPRISED FOR SEE A
FEW FLURRIES DURING THIS TIME AS WELL...ESPECIALLY IF WE CAN GET
SOME ENHANCEMENT FROM THE RIGHT ENTRANCE REGION OF THE 250MB JET.
THURS WILL BE BREEZY AS THE HIGH PRESSURE OVER THE NORTHERN PLAINS
MOVES EAST. CLOUDS WILL DECREASE LATE IN THE DAY AS WINDS PICK UP
OUT OF THE SOUTH AT 15 TO 20 KTS DUE TO THE STRONG PRESSURE GRADIENT
ACROSS WESTERN KANSAS. FRIDAY WILL BE SEASONABLE...WITH SOME HIGH
CLOUDS LIMITING AFTERNOON TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 230 AM MST SAT JAN 18 2014
FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
AVIATION CONCERN WILL BE HOW STRONG WINDS GET LATE THIS MORNING
THROUGH AFTERNOON AND IF BLOWING DUST CAN DEVELOP. IF
SO...RESTRICTED VISIBILITIES ARE POSSIBLE.
UPPER JET TO MOVE ACROSS THE AREA WITH PEAK WINDS VERY LATE THIS
MORNING THROUGH EARLY AFTERNOON. NORTHWEST WINDS GUSTING 40-45KTS
EXPECTED IN THE 18Z-21Z TIME FRAME WITH SLIGHTLY LOWER GUSTS 2-3
HOURS EITHER SIDE. AROUND 00Z NORTHWEST WINDS AROUND 15KTS WILL
BACK TO THE WEST THEN SOUTHWEST THROUGH 12Z AT 8-13KTS...HIGHEST
AT KGLD.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MST SAT JAN 18 2014
TODAY...CURRENT RED FLAG WARNING AREAL COVERAGE LOOKS GOOD AS RH
VALUES AROUND 20 PERCENT COMBINE WITH NORTHWEST WINDS GUSTING UP
TO 50 MPH...POSSIBLY A BIT HIGHER IN SPOTS. AS FAR AS
TIMING...CURRENT START TIME MAY BE A FEW HOURS EARLY.
SUNDAY...RH VALUES FALL INTO THE 20-25 PERCENT RANGE ACROSS THE
AREA DURING THE EARLY AFTERNOON. NORTHWEST WINDS OF 15 TO 20 MPH
ARE POSSIBLE CREATING NEAR CRITICAL FIRE WEATHER CONDITIONS.
SOMETHING TO WATCH.
MONDAY...RH VALUES FALL TOWARD 25 PERCENT BY MID AFTERNOON.
NORTHWEST WINDS OF 20 TO 25 MPH WITH HIGHER GUSTS EXPECTED WHICH
WILL CREATE NEAR CRITICAL FIRE WEATHER CONDITIONS. LATER SHIFTS
WILL NEED TO RE-EVALUATE FOR POSSIBLE FIRE WEATHER HIGHLITE.
&&
.CLIMATE...
ISSUED AT 230 AM MST SAT JAN 18 2014
RECORD AND/OR NEAR RECORD HIGH TEMPERATURES ARE POSSIBLE SUNDAY
JANUARY 19 AT HILL CITY AND MCCOOK. CURRENT RECORDS FOR THE DATE
ARE:
HILL CITY...66 IN 2006 AND PREVIOUS YEARS
MCCOOK......66 IN 1997
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 10 AM MST /11 AM CST/ THIS MORNING TO 5
PM MST /6 PM CST/ THIS AFTERNOON FOR KSZ001-002-013>015-
027>029-041-042.
WIND ADVISORY FROM 9 AM MST /10 AM CST/ THIS MORNING TO 5 PM
MST
/6 PM CST/ THIS AFTERNOON FOR KSZ001>004-013>016-027>029-
042.
CO...RED FLAG WARNING FROM 10 AM THIS MORNING TO 5 PM MST THIS
AFTERNOON FOR COZ252>254.
WIND ADVISORY FROM 9 AM THIS MORNING TO 5 PM MST THIS AFTERNOON
FOR COZ090-091.
NE...RED FLAG WARNING FROM 10 AM THIS MORNING TO 5 PM MST THIS
AFTERNOON FOR NEZ079.
WIND ADVISORY FROM 9 AM MST /10 AM CST/ THIS MORNING TO 5 PM
MST
/6 PM CST/ THIS AFTERNOON FOR NEZ079>081.
&&
$$
SHORT TERM...99
LONG TERM...JJM
AVIATION...99
FIRE WEATHER...99
CLIMATE...99
AREA FORECAST DISCUSSION
NWS GRAY ME
1103 AM EST SAT JAN 18 2014
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP OFF THE SOUTHERN NEW ENGLAND COASTLINE
TODAY...ALLOWING FOR ACCUMULATING SNOWFALL. THE SNOW WILL TAPER TO
SCATTERED SNOW SHOWERS TONIGHT. AN UPPER LEVEL TROUGH WILL CROSS THE REGION
SUNDAY...FOLLOWED BY AN ARCTIC FRONT EARLY MONDAY MORNING.
THEREAFTER...VERY COLD AND DRY WEATHER IS EXPECTED THROUGH MUCH OF
THE WEEK. THE EXCEPTION WILL BE THE MOUNTAINS WHERE UPSLOPE SNOW
SHOWERS WILL OCCUR.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1045 AM UPDATE...HAVE MADE SOME MINOR ADJUSTMENTS TO THE PREVIOUS
FORECAST BASED ON LATEST TRENDS IN OBSERVATIONS...RADAR/SAT
IMAGERY...AND LATEST MESOSCALE MODEL DATA. OVERALL...THE GOING
FORECAST IS LARGELY SUPPORTED BY THE LATEST DATA.
THE MAIN QUESTION REMAINS WHETHER OR NOT A HEAVY BAND OF
PRECIPITATION WILL MOVE NORTHWARD UP THE COASTAL PLAIN OF NH AND
ME THIS AFTERNOON AND EVENING AND WHAT WILL THE P-TYPE BE. THE
HRRR HAS BEEN WAFFLING AROUND A BIT WITH RESPECT TO THE
POSITIONING OF THE RELATIVELY NARROW BAND OF FORCING ASSOCIATED
WITH STRONG PRESSURE FALLS AND MID LEVEL FRONTOGENESIS. WOULD LIKE
TO SEE A LITTLE MORE CONSISTENCY THERE.
THE LATEST RUN OR TWO OF THE RAP SEEMS TO BE CORRESPONDING BETTER
TO THE BLOSSOMING BAND OF PRECIPITATION ACROSS EASTERN
MASSACHUSETTS...WHICH AT LEAST FOR THE TIME BEING...IS MOVING
NEARLY DUE NORTH. HAVE CONTINUED TO LEND MORE CREDENCE TO THE
LATEST RAP AS A RESULT.
A LITTLE LIGHT RAIN AT THE START SHOULD TRANSITION TO A HEAVY WET
SNOW ONCE THE STRONG UVV/S ARRIVE IN A FEW HOURS. FORECAST SNOW
AMOUNTS HAVE BEEN ADJUSTED A BIT...MAINLY TO ALLOW FOR A MORE
NARROW BAND OF HEAVIER SNOWFALL ON THE COASTAL PLAIN.
HOWEVER...THIS REMAINS A VERY FLUID SITUATION WITH LOW TO MODERATE
CONFIDENCE.
ISOLD THUNDER WILL BE POSSIBLE IN THE HEAVIEST BAND OF
PRECIPITATION...AS WE HAVE SEEN JUST SOUTH OF BOSTON.
PREVIOUS DISCUSSION...
UPDATE...MINOR CHANGES TO ACCOUNT FOR LATEST OBSERVATIONAL
TRENDS...MAINLY TO DELAY LIKELY POP SLIGHTLY BY AN HOUR OR SO.
NOTED IS DEVELOPING BAROCLINIC LEAF OFF THE MID ATLANTIC. WITHIN
IT EXPANDING...COOLING CLOUD TOPS AND LIGHTNING ARE BEING OBSERVED
OFF THE COAST. SOME LIGHT PCPN IS WORKING NWD THRU MA ATTM...WITH
TEMPS BELOW FREEZING IN SRN NH THIS SHOULD BE ALL SN. A MORE
WIDESPREAD SNFL CONTINUES TO DEVELOP WITHIN THE WARM CONVEYOR BELT
NW OF KNYC THRU KBUF. THIS WILL WORK E AND FILL IN WITH TIME.
PREVIOUS DISCUSSION...S/WV TROF NEARING THE EAST COAST THIS
MORNING IS ALREADY AIDING IN THE DEVELOPMENT OF WEAK LOW PRES
INVOF DELMARVA. THIS LOW PRES IS FORECAST TO TRACK NEWD TOWARDS
SRN NEW ENGLAND. ADDITIONAL S/WV ENERGY WILL HANG BACK ACROSS THE
ERN GREAT LAKES. BETWEEN THE TWO FEATURES A SFC TROF IS EXPECTED
TO DEVELOP...THIS BEING THE FORECAST PROBLEM OF THE DAY.
AS IT STANDS NOW PCPN IS ALREADY BREAKING OUT TO THE N OF THE SFC
LOW. THIS WILL GRADUALLY EXPAND NWD WITH TIME...REACHING SRN ZONES
THIS MORNING..AND THE NRN HALF OF THE CWFA BY THIS AFTERNOON. AS
LOW PRES DEEPENS NE OF CAPE COD...INVERTED SFC TROF WILL SERVE TO
FOCUS AND ENHANCE QPF. ECMWF AND GFS HAVE BEEN RELATIVELY
CONSISTENT WITH BETWEEN 0.50 AND 0.75 INCHES QPF FOR COASTAL
PORTIONS OF SRN NH AND SWRN ME. NAM HAS WAFFLED A BIT...WITH ONE
RUN BEING DRY AND THE NEXT INCREASING QPF CLOSER TO THE GLOBAL
SOLUTIONS. OPTED TO TAKE A BLEND OF THE THREE MODELS...WITH HPC
AND RFC GUIDANCE AS WELL.
NEXT ISSUE IS SFC TEMPS. FOR THE LAST COUPLE OF DAYS MODEL
GUIDANCE HAS BEEN INSISTENT ON THE BOUNDARY LAYER WARMING ABOVE
FREEZING FOR PART OF IF NOT MOST OF THE DAY. HOWEVER...ATTM DEW
POINTS ARE THE LOW TO MID 20S...WITH WIDESPREAD TEMPS IN THE 20S.
AS PCPN BEGINS...WET BULB COOLING SHOULD SERVE TO LOCK MUCH OF THE
INTERIOR BELOW FREEZING. ELY FLOW DEVELOPING AT OR JUST ABOVE SFC
WILL TRY AND BRING IN SOME MILDER AIR...ESPECIALLY NEAR THE COAST
AND PENOBSCOT BAY. HOWEVER...IT IS BEGINNING TO LOOK LIKE A
MAJORITY SN EVENT FOR THE AREA.
DESPITE MARGINAL SFC TEMPS...SNOW GROWTH ZONE IS WELL ALIGNED
WITH THE GREATEST LIFT...AND SEE NO REASON WHY RATIOS WON/T BE A
LITTLE BETTER THAN 10 TO 1. GIVEN THE TEMPS AND QPF...SNFL AMOUNT
ARE A GENERAL 2 TO 4 INCHES S OF THE MTNS...WITH A POCKET OF 4 TO
6 INCHES BOUNDED BY KCON...KLCI...AND KPWM. IT IS THIS AREA THAT
THE MAJORITY OF MODEL GUIDANCE FAVORS FOR THE PLACEMENT OF SFC
TROF. WITHIN THIS AREA IT WOULD NOT BE SURPRISING TO SEE A NARROW
BAND OF 6 PLUS INCH AMOUNTS. HOWEVER THESE INVERTED TROF FEATURES
ARE VERY DIFFICULT TO PINPOINT UNTIL THEY ARE SETTING UP. FOR NOW
WILL ISSUE WINTER WX ADVISORIES FOR SRN NH AND COASTAL ME...WITH
STRONGER WORDING ACROSS EXTREME SERN NH AND SWRN ME. ONCE THE TROF
SETS UP AND IF IT LOOKS LIKE THERE IS A SIGNIFICANT ENHANCEMENT OF
PCPN OCCURRING...THE NEXT SHIFTS COULD CONSIDER A SMALL AREA
UPGRADE TO WARNINGS.
EXPECT THAT STRONG LIFT AND LOW STATIC STABILITY ALOFT WILL LEAD
TO CONVECTIVE ELEMENTS WITHIN THE OVERALL PCPN SHIELD. THIS WILL
RESULT IN AREAS OF +SN AT TIMES...ESPECIALLY CLOSER TO THE SFC LOW
AND STRONGEST LIFT. IN FACT SOME MODELS INDICATE UNSTABLE
CONDITIONS ALOFT...AND IF LIFT IS STRONG ENOUGH A RUMBLE OF
THUNDER AROUND NEW ENGLAND CANNOT BE RULED OUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
SNFL WILL TAPER OFF THIS EVENING...BUT STEADIER PCPN WILL LINGER
WITHIN SFC TROF. THIS IS MOST LIKELY TO BE ALIGNED NEAR THE
COAST...AND BACK INTO SRN NH. THIS IS WHERE HIGHEST POP WILL
REMAIN THRU THE NIGHT.
CYCLONIC FLOW WILL CONTINUE INTO SUN...AHEAD OF APPROACHING ARCTIC
BOUNDARY. EXPECT THAT SCT SHSN WILL BE POSSIBLE THRU MUCH OF THE
DAY...BECOMING MORE WIDESPREAD AS FNT NEARS...ESPECIALLY FOR THE
HIGHER TERRAIN.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
YET ANOTHER ARCTIC FRONT WILL CROSS THE REGION DURING THE EARLY
MORNING HOURS ON MONDAY. WINDS WILL BE GUSTY BOTH AHEAD OF AND
BEHIND THIS FEATURE. SUFFICIENT INSTABILITY AND MOISTURE TO ALLOW
FOR A BRIEF PASSING SNOW SQUALL IN MANY AREAS AS WELL AS THE COLD
AIR BLASTS INTO THE REGION.
A PERIOD OF LIGHT SNOW MAY LINGER INTO THE EARLY AFTERNOON HOURS
AS WELL AS THE 00Z MODEL SUITE CONTINUES TO SHOW A WEAK WAVE
FORMING ALONG THE ARCTIC BOUNDARY.
TEMPERATURES REMAIN RELATIVELY STEADY ON MONDAY. HOWEVER...BY
MONDAY NIGHT...MUCH OF THE REGION WILL BE BELOW ZERO...WITH THE
EXCEPTION POSSIBLY THE COASTLINE.
NEW EURO ATTEMPTS TO DEVELOP A STRONG COASTL LOW OFF THE SOUTHERN
NEW ENGLAND COASTLINE THURSDAY INTO THURSDAY NIGHT. LATEST GFS
ENSEMBLE MEAN HINTING AT THIS POSSIBILITY AS WELL...HOWEVER THIS
MODEL IS MORE PROGRESSIVE. WILL AWAIT ANOTHER MODEL RUN...AND IF
STILL PRESENT...THIS WILL REQUIRE BOOSTING POPS FOR LATER IN THE
WORK WEEK.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM....SNFL MIXED WITH RAIN/SLEET AT TIMES WILL THEN BEGIN
SPREADING INTO THE AREA FROM S TO N. IFR OR LOWER CONDITIONS ARE
POSSIBLE THRU THE DAY...ESPECIALLY NEAR THE COAST AND S OF KAUG.
SN WILL TAPER OFF TONIGHT...BUT SCT SHSN WILL LINGER INTO SUN.
LONG TERM...CONDITIONS POSSIBLY BRIEFLY DROPPING TO LIFR IN ANY
SCATTERED SNOW SQUALLS WITH THE PASSAGE OF THE ARCTIC FRONT EARLY
MONDAY MORNING. OTHERWISE...MAINLY VFR CONDITIONS OUTSIDE THE
MOUNTAINS.
&&
.MARINE...
SHORT TERM...SEAS AOA 5 FT WILL CONTINUE FOR THE BETTER PART OF
THE DAY TODAY. SEAS BUILD AGAIN SUN AS COLD FNT APPROACHES THE
WATERS...WITH WIND GUSTS INCREASING TO 25-30 KTS.
LONG TERM...SCA CONDITIONS EXPECTED SUNDAY NIGHT INTO EARLY MONDAY
MORNING AHEAD OF AND BEHIND THE ARCTIC FRONT. GALE FORCE WINDS ARE
POSSIBLE AS WELL WITH THIS EVENT. THEREAFTER...A GUSTY WNW FLOW
WILL BRING SCA CONDITIONS FOR MUCH OF THE UPCOMING WORK WEEK.
&&
.HYDROLOGY...
AN ICE JAM IS STILL CAUSING HIGH WATER ON THE
KENNEBEC NEAR NORTH SIDNEY. THE WATER LEVEL HAS BEEN DECREASING
DURING THE EARLY MORNING HOURS AND IT CURRENTLY REMAINS BELOW
FLOOD STAGE. THE ICE JAMS REMAIN HIGHLY UNPREDICTABLE...WITH RAPID
FLUCTUATIONS IN WATER LEVELS OVER SHORT PERIODS OF TIME. ICE JAMS
ARE ALSO POSSIBLE ON OTHER RIVERS ACROSS THE REGION AND PEOPLE
LIVING ALONG STREAMS AND RIVERS SHOULD MONITOR WATER LEVELS
CLOSELY...ESPECIALLY AS THE RETURN OF COLD WEATHER CAUSES ICE TO
BUILD BACK UP.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MEZ018-
019-023-024.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
MEZ025>028.
NH...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
NHZ005>010-013-014.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL MIDNIGHT EST
TONIGHT FOR ANZ150-152-154.
&&
$$
NEAR TERM UPDATE...EKSTER
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
216 AM EST SAT JAN 18 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT INTO EARLY SATURDAY
MORNING. HIGH PRESSURE WILL RETURN BY SATURDAY AFTERNOON. ANOTHER
COLD FRONT WILL SWING ACROSS THE REGION ON SUNDAY. AN EXTENDED
PERIOD OF WELL BELOW NORMAL TEMPERATURES IS EXPECTED DURING THE
MIDDLE AND END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
NO MAJOR CHANGES NEC TO THE FORECAST PACKAGE TNGT. WITH 00Z NAM
AND RAP COMING IN DRY ACROSS THE AREA SEE NO REASON TO BUMP UP
POPS HIGHER THAN 20% OVRNGT. CAN`T RULE OUT SOME
SPRINKLES/FLURRIES OVR NRN AREAS. OTHERWISE...PRTLY CLOUDY ON AVG
WITH LO TEMPS RANGING FRM THE MID/UPR 20S OVR THE PIEDMONT TO THE
MID/UPR 30S NEAR THE CST.
PREVIOUS DISCUSSION...
A COLD FRONT WILL QUICKLY APPROACH THE LOCAL AREA BY THIS
EVENING...THEN MOVES THRU TONIGHT INTO EARLY SAT MORNING. LATEST
MODEL GUIDANCE IS NOT ALL THAT ENTHUSIASTIC ABOUT THE CHANCE FOR
MEASURABLE PCPN ACROSS THE FA TONIGHT. THIS IS MOSTLY DUE TO THE
FAR NE TRACK OF THE UPPER LOW (ACROSS THE OH VALLEY/EASTERN GREAT
LAKES) AND THE FAR NORTHERN TRACK OF THE SFC LOW. THE MODELS DUE
SHOW A LITTLE ENERGY TRANSLATING TO THE COAST AND INTERACTING WITH
THE GULF STREAM BETWEEN 06Z-12Z. HOWEVER...BY THEN IT WILL BE TOO
LITTLE TOO LATE FOR OUR FA SINCE THE COLD FRONT WILL BE THRU BY
THEN AND THE BEST CHANCE FOR PCPN REMAINS OFFSHORE. WILL CARRY
MAINLY GHOST POPS OVERNIGHT (<15%) FOR THE POSSIBILITY OF ISOLATED
SPRINKLES/FLURRIES AS THE FRONT PASSES. SLIGHT CHC POPS (20%) WERE
LEFT IN THE FAR NW COUNTIES BETWEEN 03-06Z...THEN ACROSS FAR
EASTERN AREAS BETWEEN 06-12Z. AT BEST...THERE MAY BE A QUICK SNOW
SHOWER IN THESE AREAS WITH NO SNOW ACCUMULATION EXPECTED. LOWS
TONIGHT IN THE MID 20S NW TO THE MID 30S AT THE COAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
A BRIEF RETURN OF HIGH PRESSURE WILL OCCUR ON SATURDAY WITH
PLENTY OF SUNSHINE. TEMPS WILL BE COOLER THAN TODAY IN THE WAKE
OF THE COLD FRONT. HIGHS IN THE MID 30S TO LOW 40S WITH A DECENT
BREEZE...MAKING IT FEEL LIKE THE 20S.
NEXT POTENT SHORTWAVE (AND ASSOCIATED COLD FRONT) DIGS ACROSS THE
OH VALLEY EARLY SAT NGT...THEN SWINGS THRU THE MID ATLANTIC LATE
SAT NIGHT INTO MIDDAY SUN. THIS SYSTEM WILL ALSO HAVE LIMITED LOW
LEVEL MOISTURE TO WORK WITH...AND COMBINED WITH THE SHEERING
NATURE OF THE UPR TROUGH WILL MAKE IT HARD TO PRODUCE ANY
ACCUMULATING PCPN. WILL KEEP THE FORECAST DRY SAT NIGHT...THEN
MAINTAIN SLIGHT CHC POPS (20%) ACROSS THE EASTERN SHORE SUN
MORNING. CANNOT RULE OUT A FEW FLURRIES SUN MORNING ACROSS THE
ENTIRE CWA. BECOMING PARTLY OR MOSTLY SUNNY FROM LATE SUN MORNING
THRU SUN AFTN...AS THAT FRONT PUSHES OUT TO SEA AND HIGH PRESSURE
BUILDS IN FROM THE SW. BREEZY WITH MAX TEMPS IN THE 40S TO NR 50.
HIGH PRESSURE REMAINS IN PLACE MONDAY MORNING BEFORE A COLD FRONT
SAGS SOUTHWARD INTO THE AREA LATE MONDAY AFTERNOON. DRY WITH
HIGHS IN THE 50S TO AROUND 60.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS AGREE ON GENERAL PATTERN IN THE MEDIUM RANGE WHICH WILL BE
DOMINATED BY STRONG RIDGING ACRS WESTERN NORTH AMERICA...AND A DEEP
TROUGH OVER EASTERN CANADA AND THE GREAT LAKES. DIFFERENCES ARE
FAIRLY MINIMAL SO CONFIDENCE IS HIGH THAT WELL BELOW AVG
TEMPERATURES WILL PREVAIL DURING THE PERIOD...ESPECIALLY WED/THU.
OVERALL...CONDITIONS LOOK DRY AS ARCTIC AIRMASS OVERSPREADS THE
REGION FROM LATE TUE AND BEYOND. STILL SOME QUESTION THOUGH AS TO
POTENTIAL FOR SOME SNOW TUE/TUE NIGHT AS A POTENT UPPER LEVEL
SHORTWAVE TRACKS THROUGH THE MID ATLC/SE STATES AND DEVELOPS A SFC
LOW OFF THE NC COAST. CURRENT PATTERN DEPICTED BY LATEST
GFS/ECMWF/GLOBAL IS TOO PROGRESSIVE FOR MORE THAN A LOW CHC FOR
PRECIP SO WILL ONLY CARRY 20% POPS MOST AREAS AND 30% CHC FOR SE
VA/NE NC AT THIS TIME. HIGHS TUE AVG IN THE LOW 40S NE NC TO THE
LOW-MID 30S ACRS THE FAR NORTH...WITH LOWS WED IN THE TEENS NW TO
THE MID/UPPER 20S SE. EXPECT PARTLY CLOUDY TO VARIABLY SKIES
WED-FRI...ANOTHER WEAK SYSTEM MAY AFFECT THE REGION SOMETIME THU
ALTHOUGH MODELS DIVERGE IN TIMING THE SHORTWAVES IN THE W/NW FLOW
PATTERN BY THIS TIME. HIGHS WED LIKELY STAY IN THE UPPER 20S FROM
RICHMOND ON NORTH...WITH ONLY LOW 30S ACRS THE SOUTH. ONLY A SLIGHT
MODERATION EXPECTED THU/FRI...WITH HIGHS MAINLY IN THE 30S AND LOWS
IN THE TEENS TO LWR 20S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT IS CROSSING THE COAST AS OF 18/0630Z THIS MORNING AND
PRECIPITATION ALONG THE FRONT CONSISTS OF LIGHT RAIN SHOWERS. THE
LOWEST CIGS SEEN WITHIN THE LOCAL OBSERVATION NETWORK ARE AROUND
4 KFT AGL. CIGS BTWN 4-5 KT FT AGL SHOULD PERSIST THROUGH THIS
MORNING BEFORE BREAKING UP/BECOMING SCATTERED THIS AFTERNOON.
THEREFORE...VFR CONDITIONS ARE EXPECTED TO PERSIST OVER THE NEXT
24 HOURS. WINDS WILL BE SW IN THE VICINITY OF THE FRONT AND THEN
VEER TO THE W-NW BEHIND ITS PASSAGE. DECENT COLD AIR ADVECTION AND
AN AMPLIFIED SFC HIGH PRESSURE RIDGE BUILDING ACROSS THE OHIO
VALLEY TODAY WILL CAUSE THE PRESSURE GRADIENT TO TIGHTEN. BREEZY
CONDITIONS WILL DEVELOP BY MID MORNING...PEAK THIS AFTERNOON...AND
THEN DIMINISH THROUGH THIS EVENING. EXPECT W-NW WINDS OF GENERALLY
10-15 KT WITH GUSTS UP TO 20 KT WEST OF INTERSTATE 95 AND SPEEDS
OF 15 TO 20 KT WITH GUSTS UP TO 25 KT EAST OF INTERSTATE 95.
ANOTHER LOW PRESSURE SYSTEM WILL MOVE ACROSS THE OHIO VALLEY TWD
NRN VA TONIGHT...PUSHING A COLD FRONT THROUGH THE AREA ON SUNDAY.
SFC MOISTURE WILL BE LACKING DUE TO RECENT COLD AIR ADVECTION AND
BREEZY WINDS...MAKING PRECIPITATION GENERATION DIFFICULT ESPECIALLY
AS THE UPPER LEVEL ENERGY SHEARS APART DURING THE FRONTAL PASSAGE.
THIS SYSTEM WILL PRIMARILY SPREAD HIGH CLOUDS BACK INTO THE REGION
FROM THE W-NW THIS EVENING. CLOUDS ARE EXPECTED TO THICKEN AND
LOWER OVERNIGHT INTO SUN MORNING WITH LIGHT SNOW FLURRIES POSSIBLE...
HOWEVER THIS SHOULD HAVE LITTLE TO NO IMPACT ON AIRFIELD OPERATIONS.
A BRIEF SURGE OF COLDER AIR BEHIND THE FRONT WILL RESULT IN BREEZY
SW-W WINDS DEVELOPING BY MID-MORNING SUNDAY AND PERSISTING THROUGH
THE AFTERNOON BEFORE SLACKENING.
&&
.MARINE...
UPDATE...
SCA FLAGS HAVE BEEN ALLOWED TO START AT 06Z EARLY THIS MORNING AND
WILL CONTINUE THROUGH THIS EVENING. A QUICK BURST OF SW WINDS AT
LOW-END SCA SPEEDS AHEAD OF THE FRONT WILL GIVE WAY TO A STRONGER
W-NW SURGE BEHIND THE FRONT AS THE PRESSURE GRADIENT TIGHTENS AND
COLD AIR ADVECTION PROCESSES TAKE OVER. EXPECT WIND SPEEDS AROUND
20-25 KT FOR BAY/COASTAL WATERS AND AVERAGE SPEEDS OF 15-20 KT
CURRITUCK SOUND/ERN VA RIVERS. SEAS AVERAGING 2-3 FT SHOULD
QUICKLY BUILD TO 4-5 FT ONCE THE W-NW SURGE BEGINS. CHES BAY
SHOULD ALSO EXPERIENCE RAPIDLY BUILDING WAVES FROM 1-2 FT TO 3-4
FT. ALTHOUGH THERE MAY BE A LAG IN WIND SPEEDS OVER SRN COASTAL
WATERS SOUTH OF CAPE CHARLES...SEAS ARE EXPECTED TO REACH 5 FT
NEAR 20 NM DURING THE FRONTAL PASSAGE. SEAS IN THIS AREA WILL STAY
AROUND 4-5 FT THROUGH TODAY AND SHOULD BEGIN TO SUBSIDE THIS
EVENING...HOWEVER SEAS MAY LINGER AROUND 5 FT NEAR 20 NM INTO LATE
EVENING. HAVE ADDED SRN WATERS INTO SCA HEADLINES FROM CAPE
CHARLES TO CURRITUCK LIGHT BEGINNING IMMEDIATELY AND PERSISTING
UNTIL MIDNIGHT TONIGHT TO ACCOUNT FOR THE POSSIBILITY OF SLOWLY
SUBSIDING SEAS.
PREVIOUS DISCUSSION...
SCA CONDITIONS MAY RE-DEVELOP SUN AND SUN NIGHT. SCA HEADLINES MAY
NEED TO BE EXTENDED THROUGH SAT NIGHT DUE TO A LULL ANTICIPATED TO
LAST LESS THAN 12 HOURS. BENIGN CONDITIONS ARE INDICATED FOR MON AND
TUE. ANOTHER ROUND OF HEADLINES MAY BE NEEDED LATER IN THE WEEK AS
MORE COLD AIR POURS INTO THE REGION.
&&
.EQUIPMENT...
THE NOAA ALL HAZARD WEATHER RADIO (KHB-57) EMANATING FROM DRIVER,
VA ON A FREQUENCY OF 162.550 MHZ WILL BE OFF THE AIR UNTIL
FURTHER NOTICE DUE TO ANTENNA PROBLEMS. RETURN TO NORMAL SERVICE
IS NOT KNOWN AT THIS TIME.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ630>632-634>638.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR ANZ633.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ650-652-
654.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR ANZ656-658.
&&
$$
SYNOPSIS...JDM
NEAR TERM...JDM/MAS
SHORT TERM...JDM
LONG TERM...LKB
AVIATION...BMD
MARINE...BMD
EQUIPMENT...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
646 PM EST SUN JAN 19 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM EST SUN JAN 19 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT NW FLOW
ALF OVER THE GREAT LKS BTWN UPR TROF OVER EASTERN NAMERICA AND A RDG
NEAR THE PACIFIC COAST. COLD FNT ASSOCIATED WITH STRONG DISTURBANCE/
SFC LO PRES MOVING INTO WRN QUEBEC IS IN THE PROCESS OF PUSHING N-E
THRU UPR MI EARLY THIS AFTN ACCOMPANIED BY SOME GENERALLY LGT SN
MAINLY NEAR LK SUP. MUCH COLDER AIR WITH 12Z H85 TEMPS AS LO AS -27C
AT YPL IS FOLLOWING THIS FNT...AND SFC TEMPS ARE IN THE PROCESS OF
FALLING OVER THE NRN TIER. DESPITE THE INFLUX OF MUCH COLDER AIR...
THE COMBINATION OF DNVA AHEAD OF AN APRCHG SHRTWV RDG/LOWERING INVRN
BASE TOWARD 3K FT PER SHORT TERM FCST SDNGS AND ADVECTION OF DRIER
LLVL AIR OSBVD IN ONTARIO IS TENDING TO HAMPER THE INTENSITY OF LES
FOLLOWING THE FROPA. IN FACT...VSBL STLT IMAGERY IS SHOWING QUITE A
BIT OF CLRG OVER THE N HALF OF LK SUP. THERE IS ANOTHER SHRTWV NEAR
LK WINNIPEG THAT IS DIVING ESEWD TOWARD THE CWA. STLT IMAGERY DOES
SHOW SOME ENHANCED CLD IN THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF
THIS FEATURE...BUT THE LLVL DRYING IN THE NNE FLOW TO THE S OF SFC
ARCTIC HI PRES CENTERED OVER NRN MANITOBA IS LIMITING SN COVERAGE/
INTENSITY. YET ANOTHER CLIPPER TYPE SHRTWV OVER ALBERTA IS MOVING
SEWD.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE LES/SN AMOUNTS/GOING
HEADLINES AND IMPACT OF CLIPPER SHRTWVS THAT WL BE DIVING SEWD THRU
THE UPR LKS.
TNGT...SFC COLD FNT NOW DROPPING SWD THRU UPR MI WL CLEAR MENOMINEE
BY 00Z MON. INFLUX OF COLD AIR IN THE LLVL NLY FLOW BEHIND THIS
FROPA THAT IS FCST TO DROP H85 TEMPS TO ARND -23C OR -24C OVER THE
NRN TIER BY 12Z MON WL GENERATE LES IN THE FAVORED SN BELTS.
ALTHOUGH LLVL DRYING/LO INVRN BASE WL HAVE A NEGATIVE IMPACT ON THE
INTENSITY OF THE SHSN IN THE SHORT TERM...ARRIVAL OF DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH PAIR OF UPSTREAM CLIPPER SHRTWVS IS
FCST TO SLOWLY RAISE FCST INVRN BASE AND BRING ABOUT SOME DEEPER
MOISTENING. THE RESULT SHOULD BE AN INCRS IN LES INTENSITY
ESPECIALLY E OF MQT...WHERE LONGER FETCH OVER ICE FREE WATER AND
SHARPER LLVL CNVGC OVER ALGER/NRN SCHOOLCRAFT COUNTIES ON WRN FLANK
OF LAND BREEZE FLOW OFF ONTARIO WL TEND TO PLAY A POSITIVE ROLE
DESPITE SOME SLOWLY SHIFTING LLVL WINDS ACCOMPANYING PASSAGE OF UPR
DISTURBANCE. GOING LES ADVY FOR THE ERN CWA SEEMS APPROPIATE. AWAY
FM MOISTENING ASSOCIATED WITH LK SUP...DYNAMIC SUPPORT FM CLIPPER
SHRTWV WL PRODUCE NOTHING MORE THAN ISOLD-SCT LGT SHSN WITH LLVL
DRYING OFFSETTING THE ACCOMPANYING UPWARD MOTION. NLY FLOW OFF LK
SUP/ABUNDANT CLD COVER WL TEND TO MODERATE MIN TEMPS DESPITE THE
ARRIVAL OF THE COLDER AIR.
MON...CLIPPER NOW OVER ALBERTA/ACCOMPANYING DPVA AND DEEP LYR
QVECTOR CNVGC IS PROGGED TO SLIDE SEWD ACRS THE UPR MIDWEST/UPR LKS
IN THE MRNG. THIS DISTURBANCE SHOULD MAINTAIN HIER INVRN BASE AND
PERSISTENT LES NEAR LK SUP AS H85 TEMPS FALL TO ARND -26C IN SLOWLY
SHIFTING LLVL NLY FLOW. BUT THE DIMINISHING DGZ DEPTH ACCOMPANYING
INFLUX OF EVEN COLDER AIR AS WELL AS SLOWLY SHIFTING LLVL WINDS WL
TEND TO LIMIT SN TOTALS. BUT WL CONTINUE CATEGORICAL POPS FOR LES IN
THE FAVORED SN BELTS E OF MQT. ALTHOUGH THERE COULD BE SOME FREQUENT
SHSN EARLY NEAR IWD CLOSER TO THE TRACK OF THIS SECOND CLIPPER...
WENT WITH NO MORE THAN LIKELY POPS OVER THE WRN SN BELTS CONSIDERING
WEAKER LLVL CNVGC/MORE ICE COVER. WITH THE ARRIVAL OF COLDER AIR AND
ABUNDANT CLD COVER IN GENERAL N FLOW OFF LK SUP...EXPECT LTL DIURNAL
TEMP RECOVERY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM EST SUN JAN 19 2014
MODELS ARE IN GOOD AGREEMENT THROUGH MID WEEK WITH DETAILS ON LES
AND A CLIPPER SYSTEM MOVING THROUGH ON WED.
STARTING 00Z TUE...THE CWA WILL BE BENEATH A BROAD UPPER
TROUGH...WITH A WEAK SHORTWAVE JUST N OF LAKE SUPERIOR. 850MB TEMPS
WILL START OUT AOB -25C. LOW LEVEL WINDS WILL BE OUT OF THE NNW AS
THE CWA IS BETWEEN A SFC TROUGH OVER THE ERN SEABOARD AND A 1040MB
HIGH CENTERED OVER ND. A TROUGH WILL BE DRAPED FROM THE SSE INTO ERN
LAKE SUPERIOR...PROMOTING CYCLONIC FLOW THERE...WHILE FLOW OVER FAR
WRN LAKE SUPERIOR WILL BE SLIGHTLY ANTICYCLONIC. LES WILL BE ONGOING
IN ALL NNW WIND SNOWBELT...BUT THE MOST INTENSE SNOW WILL BE
DOWNWIND OF ERN LAKE SUPERIOR AS CONDITIONS THERE WILL BE MORE
FAVORABLE FOR MODERATE TO LOCALLY HEAVY LES /INCLUDING INVERSION
TOPS AROUND 7KFT/. NOT MUCH CHANGES THROUGH THE REST OF MON
NIGHT...EXCEPT THAT THE SFC HIGH WILL SLIDE TO FAR SW MN...MAKING
FOR EVEN LESS FAVORABLE FLOW AND SUBSIDENCE OVER WRN LAKE
SUPERIOR...WHILE THE TROUGH OVER ERN LAKE SUPERIOR REMAINS. THE MOST
UNCERTAINTY WITH LOCAL EFFECTS IS WITH ICE COVERAGE OVER WRN LAKE
SUPERIOR THAT MAY CLOSE DOWN PORTIONS OF THE LAKE TO LES. THERE WAS
GOOD ICE COVERAGE OVER THE W WHEN LOOKING AT SATELLITE IMAGERY
YESTERDAY...BUT WITH STRONG SW WINDS LAST NIGHT TURNING MORE NWLY
TODAY...NOT SURE ABOUT THE COVERAGE AND LOCATION OF THAT ICE INTO
THE FUTURE. THE NIGHT SHIFT LAST NIGHT PUT UP AN ADVISORY FOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES...WHICH STILL LOOKS GOOD
THROUGH MON NIGHT.
THEN FOR TUE...THE SFC HIGH CONTINUES TO MOVE SE AS THE SFC TROUGH
OVER THE ERN LAKE DIMINISHES. FLOW BECOME VERY ANTICYCLONIC OVER ALL
BUT EXTREME ERN LAKE SUPERIOR /WHERE IT WILL BE NEUTRAL/ BY 00Z WED.
850MB TEMPS ALSO INCREASE TO AROUND -20C UNDER THE SFC RIDGE TUE.
SHOULD SEE LES DIMINISH THROUGH THE DAY...ESPECIALLY OVER THE W AND
CENTRAL. EVEN WITH CONDITIONS BEING UNFAVORABLE FOR SIGNIFICANT LES
OVER CENTRAL AND WRN UPPER MI...AREAS DOWNWIND OF LAKE SUPERIOR
SHOULD CONTINUE TO SEE SNOW...WHICH WOULD MAINLY BE AREAS N OFF THE
PORCUPINE MOUNTAINS OVER THE NWRN CWA. EXTENDED PREVIOUSLY MENTIONED
HEADLINES THROUGH TUESDAY AS THE LAKE TROUGHING SHOULD STICK AROUND
OVER ERN LAKE SUPERIOR...HELPING TO CONTINUE LES THROUGH MUCH OF THE
DAY. TUE LOOKS TO BE THE COLDEST DAY OF THE WEEK WITH HIGHS IN THE
SINGLE DIGITS ABOVE ZERO IN MOST LOCATIONS.
A CLIPPER SYSTEM BEGINS TO IMPACT WEATHER OVER THE CWA STARTING TUE
NIGHT AS THE SHORTWAVE MOVES TO N OF LAKE SUPERIOR IN ONTARIO BY 12Z
WED...BRINGING A BROAD...WEAK SFC LOW TO THE AREA. THIS LOW LOOKS TO
BE ENHANCED BY LAKE AGGREGATE AS A MESO LOW MAY FORM OVER LAKE
SUPERIOR...BUT TO WHAT MAGNITUDE AND EXACTLY WHERE IS UNCERTAIN. THE
12Z/19 NAM...00Z/19 GLOBAL GEM AND TO SOME EXTENT THE 00Z/19 ECMWF
FAVOR THE MESO LOW TO MOVE OVER E CENTRAL LAKE SUPERIOR...MOVING
INTO UPPER MI SOMEWHERE E OF MARQUETTE WED EVENING. THIS PATH IS
TYPICALLY WITH THIS TYPE OF PATTERN...BUT THE EXACTLY WHERE THAT LOW
MOVES WILL DETERMINE WHERE THE STRONGEST SNOW AND WIND WILL FOCUS.
THIS COULD BE QUITE AN INTERESTING EVENT OVER A SHORT PERIOD OF TIME
AS THE MESO LOW WILL VERY QUICKLY SHIFT SE AS IT MOVES OFF OF LAKE
SUPERIOR...WHILE AT THE SAME TIME A 1050MB HIGH MOVES ACROSS THE
DAKOTAS INTO THE CENTRAL PLAINS...SHUNTING A 1030MB SFC RIDGE INTO
THE CWA LATE WED NIGHT INTO THU. MOST OF THE CWA WILL SEE GUSTY
WINDS AS A RESULT OF THE PRESSURE GRADIENT AND PRESSURE RISE...BUT
THE AREA OF MOST CONCERN IS ON THE W SIDE OF THE TRACK OF THE
POSSIBLE MESO LOW...WHERE BLIZZARD LIKE CONDITIONS MAY BE POSSIBLE.
WITH LOW LEVEL WINDS OUT OF THE NNE FOR ABOUT 6 HOURS ALONG AND
BEHIND THE MESO LOW AND FROM JUST AHEAD TO JUST BEHIND THE
SHORTWAVE...NCENTRAL UPPER MI WOULD BE FAVORED FOR UPSLOPE AND LAKE
ENHANCEMENT THAT MAY MAKE FOR VERY TREACHEROUS CONDITIONS SOMEWHERE
IN THE LATE WED AFTERNOON THROUGH WED EVENING TIME FRAME.
AGAIN...THESE ARE PRETTY LOCALIZED CONDITIONS WHICH WILL BE
DIFFICULT TO EXACTLY PREDICT EVENT A DAY OUT...BUT THE CHANCE OF
THIS HAPPENING SOMEWHERE ACROSS NCENTRAL UPPER MI IS PRETTY GOOD
GIVEN THE OVERALL PATTERN. OUTSIDE OF THE IMMEDIATE AREA AFFECTED BY
THE MESO LOW...THE REST OF NWRN UPPER MI LOOKS FAVORED FOR A GOOD
BURST OF SNOW AS THE SHORTWAVE PASSES.
EXPECT LES WED NIGHT AS LOW LEVEL WINDS SHIFT FROM NLY TO NWLY WITH
-25C 850MB TEMPS...BUT WITH THE SFC RIDGE PASSING OVERHEAD ON
THU...THE LES SHOULD QUICKLY WEAKEN THU MORNING/EARLY AFTERNOON.
HOWEVER...BY LATER THU...WINDS WILL BECOME MORE CYCLONIC AHEAD OF
ANOTHER CLIPPER THAT WILL STAY MAINLY NE OF THE CWA. THE MORE
FAVORABLE CURVATURE TO THE FLOW WILL FAVORED THE KEWEENAW FOR LES AS
STRONG WINDS WILL BE OUT OF THE WSW THROUGH 06Z FRI...VEERING OUT OF
THE WNW BEHIND THE CLIPPER BY 18Z FRI. 850MB TEMPS LATE THU THROUGH
FRI WILL BE IN THE -15C TO -20C RANGE...WHICH WILL PUT MORE OF THE
THERMAL PROFILE IN THE DGZ...BUT INVERSION HEIGHTS LOOK TO ONLY BE
4-5KFT.
UNCERTAINTY INCREASES CONSIDERABLY FOR THE WEEKEND AS MODELS HAVE
NOT SHOWN GOOD CONTINUITY WITH THE PLACEMENT OF FEATURES THIS FAR
OUT. ONE TREND THAT CAN BE NOTED IS THAT THE COLDER AIR /850MB TEMPS
BELOW -30C/ SHOWN IN PREVIOUS SEVERAL MODEL RUNS MOVING OVER THE CWA
IS NOW BEING SHOWS AS MORE OF A GLANCING BLOW...WITH THE COLDEST AIR
TO THE NE. THIS COULD CHANGE...BUT AT LEAST IT IS A NOTABLE TREND
FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 645 PM EST SUN JAN 19 2014
A COLD NORTHERLY FLOW OF ARCTIC AIR ACROSS LAKE SUPERIOR WILL BRING
LAKE EFFECT -SHSN TO KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
HOWEVER...A FEED OF LOW-LEVEL DRY AIR ASSOCIATED WITH COLD HI PRES
OVER SCENTRAL CANADA WILL TEND TO LIMIT THE INTENSITY OF THE SNOW.
THUS...EXPECT MVFR CONDITIONS TO PREDOMINATE AT ALL TERMINALS. SOME
PERIODS OF VFR CONDITIONS WILL PROBABLY OCCUR...AND THE BEST CHC FOR
IFR CONDITIONS WILL BE AT KIWD MON MORNING WHEN A PASSING
DISTURBANCE IN THE PRESENCE OF A FAVORABLE NNE FLOW AND DEEPER
MOISTURE MAY ENHANCE THE SHSN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EST SUN JAN 19 2014
EXPECT N TO NW WINDS UP TO 25 TO 30 KTS TONIGHT AND MON E OF ARCTIC
HI PRES IN SCENTRAL CANADA. WITH A VERY COLD AIRMASS MOVING INTO THE
UPPER LAKES...THE RESULTING WAVE ACTION WILL CAUSE WIDESPREAD HEAVY
FREEZING SPRAY.
HEAVY FREEZING SPRAY WILL CONTINUE ACROSS ALL OF LAKE SUPERIOR
THROUGH AT LEAST TUESDAY IF NOT LONGER AS AREA IS ENTRENCHED IN COLD
AIR. NEXT GALE EVENTS LOOK TO BE ACROSS CENTRAL AND EASTERN LAKE
SUPERIOR LATE WEDNESDAY INTO WEDNESDAY NIGHT AND ANOTHER EVENT FOR
THURSDAY NIGHT ACROSS THE SAME AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST TUESDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR
LSZ249>251-266-267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR LSZ244-
245-248-264-265.
HEAVY FREEZING SPRAY WARNING FROM 7 AM MONDAY TO 7 AM EST
TUESDAY FOR LSZ243-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
447 PM EST SAT JAN 18 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 446 PM EST SAT JAN 18 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW VERY FAMILIAR UPR
AIR PATTERN WITH DEEP TROF OVER CENTRAL/ERN NAMERICA DOWNSTREAM OF
HI AMPLITUDE RDG OVER THE W. ALTHOUGH SOME LO CLDS/LGT SHSN OR
FLURRIES WERE ARND INTO EARLY AFTN WITH LLVL MSTR TRAPPED UNDER LO
INVRN SHOWN ON THE 12Z INL/GRB RAOBS...ARRIVAL OF DRIER LLVL AIR
DEPICTED ON THE INL RAOB HAS TENDED TO DIMINISH THIS LO CLD.
OTRW...THERE IS RELATIVELY QUIET WX OVER UPR MI TDAY GIVEN SHRTWV
RDG/MID LVL DRY AIR SHOWN ON THE RAOBS DOMINATING THE UPR LKS TO THE
N OF POTENT CLIPPER SHRTWV DIGGING SEWD THRU THE MIDWEST. NEXT
DISTURBANCE IN THE NEVER ENDING PARADE OF CLIPPER SHRTWVS IS NOW
DIGGING SSEWD THRU NRN MANITOBA AND INTO FAR NW ONTARIO. FAIRLY
SHARP PRES FALLS AND EXTENSIVE CLD COVER ARE EVIDENT IN MANITOBA AND
NW ONTARIO AHEAD OF THIS SHRTWV.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE IMPACT ON POPS/WINDS/
BLSN OF SHRTWV DIGGING SEWD INTO NW ONTARIO AND TEMPS TRENDS TNGT.
TNGT...SHRTWV/ACCOMPANYING SFC LO OVER NW ONTARIO THIS EVNG ARE
PROGGED TO MOVE TO NEAR JAMES BAY BY 12Z SUN...WITH ATTENDANT COLD
FNT REACHING THE KEWEENAW TOWARD 12Z. MODELS INDICATE THE SFC LO WL
DEEPEN FM ABOUT 995MB THIS EVNG TO 985MB ON SUN MRNG AS THE SHRTWV
DIGS INTO THE MEAN UPR TROF. ALTHOUGH BULK OF THE ACCOMPANYING
DPVA/DEEP LYR QVECTOR CNVGC ARE PROGGED TO SWING THRU ONTARIO AND N
OF THE CWA IN THE 06Z-12Z TIME FRAME...SOME OF THIS FORCING DOES
IMPACT UPR MI. MODELS INDICATE FAIRLY DEEP MOISTENING...WHICH IS
BACKED UP BY COLDER CLD TOPS AND UPSTREAM OBS IN NRN MANITOBA AND
SASKATCHEWAN SHOWING FAIRLY WDSPRD LGT SN EVEN ON THE ACYC SIDE OF
SHRTWV TRACK. GIVEN THESE OBS...SUSPECT THE HIER QPF UP TO 0.20 INCH
OVER THE W THRU 12Z SUN SHOWN BY THE 12Z NAM/REGIONAL GEM MAY BE ON
THE RIGHT TRACK DESPITE MARGINAL H85 TEMPS FOR LES. STRENGTHENING
UPSLOPE W-SW FLOW WOULD ALSO TEND TO ENHANCE PCPN TOTALS IN THIS
AREA. THE COMBINATION OF THE FALLING SN AND GUSTY WINDS OVER THE
MORE EXPOSED KEWEENAW PENINSULA ACCENTUATED BY H925 WINDS UP TO
35-40 KTS WL LIKELY CAUSE BLSN/SHARPLY REDUCED VSBY. PLAN TO REISSUE
SPS FOR THIS AREA. DOWNSLOPE NATURE OF WSW FLOW WL TEND TO LIMIT QPF
OVER THE CNTRL ZNS. AS FOR TEMPS...READINGS MAY FALL OFF FAIRLY
QUICKLY EARLY UNDER CLR-PCLDY SKIES...BUT COMBINATION OF INCRSG
CLDS/WINDS BY LATE EVNG SHOULD CAUSE TEMPS TO REBOUND...ESPECIALLY
IN THE DOWNSLOPE AREAS NEAR LK SUP.
SUN...AS SHRTWV/SFC LO MOVE INTO QUEBEC...ATTENDANT COLD FNT WL
CROSS UPR MI...CLRG MENOMINEE ARND 18Z. THERE MAY BE A PERIOD OF
HEAVIER SHSN/BLSN NEAR LK SUP E OF MQT ACCOMPANYING THE FROPA WITH
WSHFT TO THE NW AND GUSTY WINDS/H925 WINDS STILL NEAR 30 KTS. OPTED
TO INCLUDE THIS AREA IN SPS ISSUED FOR THE NW CWA TNGT. ALTHOUGH
FCST NNW FLOW IN THE WAKE OF THIS FROPA AND H85 TEMPS FALLING TO
ARND -20C OVER THE NRN TIER BY 00Z MON WL BE FVRBL FOR LES IN THE
FAVORED SN BELTS...DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE OF
SHRTWV PASSAGE THAT IS FCST TO SHARPEN INVRN ARND 3K FT WL TEND TO
LIMIT THE INTENSITY OF THE LES...ESPECIALLY OVER THE W DOWNWIND OF
MORE ICE BUILDUP OVER WRN LK SUP. EXPECT LESS BLSN IN THE AFTN GIVEN
TREND FOR DIMINISHING WINDS WITH CLOSER APRCH OF ARCTIC HI PRES.
ALTHOUGH ANOTHER CLIPPER SHRTWV IS FCST TO MOVE INTO NRN MN LATER IN
THE DAY WITH SOME DPVA/DEEP LYR QVECTOR CNVGC IMPACTING UPR
MI...FCST SDNGS HINT THERE WL BE TOO MUCH DRYING IN THE WAKE OF
STRONGER QUEBEC CLIPPER TO ALLOW FOR MUCH MORE THAN BKN CLDS AWAY FM
THE LES AREAS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 446 PM EST SAT JAN 18 2014
A SERIES OF CLIPPERS AND ARCTIC AIR WILL DOMINATE THE LONG TERM
PATTERN AS DEEP TROUGHING ACROSS EASTERN CANADA GENERALLY REMAINS IN
PLACE.
SUNDAY NIGHT THROUGH TUESDAY...A MID-LEVEL LOW IN THE VICINITY OF
JAMES BAY WILL SLOWLY DRIFT EASTWARD ACROSS NORTHERN QUEBEC THROUGH
THE BEGINNING OF THE PERIOD...SENDING A SERIES OF TROUGHS
SOUTHEASTWARD ACROSS UPPER MI. THE FIRST OF THESE WILL CROSS THE
AREA LATE SUNDAY NIGHT IN ASSOCIATION WITH THE CONTINUED ADVECTION
OF ARCTIC AIR ACROSS THE REGION. AN UPTICK IN LES FOR THE N TO NNW
SNOW BELTS IS EXPECTED WITH THE TROUGH PASSAGE AS LAKE EQUILIBRIUM
VALUES SURPASS 9KFT OVER EASTERN LAKE SUPERIOR. HI-RES MODEL
GUIDANCE AND EVEN SOME MEDIUM-RES GUIDANCE IS ALSO STARTING TO
INDICATE A LAKE-INDUCED SFC TROUGH/EASTERLY LAND BREEZE CONV ZONE
NORTH OF GRAND MARAIS. THE LAKE-ICE COVER IS BECOMING MORE
WIDESPREAD OVER FAR EASTERN LAKE SUPERIOR...AND WHITEFISH BAY IS
COMPLETELY FROZEN OVER PER TODAYS SATELLITE IMAGERY. THIS HAS
ALLOWED THE LAND BREEZE CONV ZONE TO SET UP FARTHER WEST TODAY...AND
WOULD EXPECT SIMILAR BEHAVIOR FOR SUNDAY NIGHT...ESPECIALLY WITH
QUITE COLD AIR FLOWING OFF ONTARIO. LITTLE SHOULD CHANGE THROUGH
MONDAY NIGHT AS PERSISTENT NNW FLOW CONTINUES TO BRING ARCTIC AIR
ACROSS THE AREA. SNOWFALL AMOUNTS ARE A LITTLE TRICKY AS THE ARCTIC
AIR TENDS TO MAKE SLR VALUES LOWER. HOWEVER...FROM EXPERIENCE SO FAR
THIS SEASON...THE EXTENDED FETCH FOR THE EASTERN CWA MAY ALLOW FOR
MORE MODERATION OF THE ARCTIC AIR...RESULTING IN A DEEPER FAVORABLE
SNOW GROWTH LAYER. HAVE THUS INCREASED RATIOS A BIT ACROSS THE EAST
WHILE LOWERED THEM ELSEWHERE. ALSO...POROUS ICE COVER DEVELOPING
ACROSS WESTERN LAKE SUPERIOR MAY LIMIT LES TO SOME
DEGREE...ESPECIALLY LOCATIONS DOWNWIND OF ISLE ROYALE. OVERALL...NOT
ANTICIPATING ANY EXTREME SNOWFALL UNLESS A CONVERGENT BAND REMAINS
ANCHORED OVER A GIVEN LOCATION...MOST LIKELY BETWEEN MUNISING AND
GRAND MARAIS...FOR AN EXTENDED PERIOD OF TIME. LOW-END ADVISORY
AMOUNTS ARE POSSIBLE SUNDAY NIGHT THROUGH MONDAY WITH GENERALLY 3 TO
6 INCHES...THOUGH LOCAL AMOUNTS OF 8 INCHES ARE POSSIBLE. THE
NORTHERN EXTENT OF A WEAK SFC RIDGE WILL BACK WINDS ON TUESDAY AND
PUSH LES ACTIVITY OFF SHORE FOR MOST LOCATIONS.
A CONTINUOUS INFLUX OF H8 TEMPS AROUND -25C WILL BE PRESENT MONDAY
THROUGH TUESDAY AND BRING RATHER COLD CONDITIONS ACROSS THE AREA.
HOWEVER...TEMPS SHOULD REMAIN WARMER THAN WAS SEEN EARLIER IN THE
MONTH. ADDITIONALLY...WINDS WILL REMAIN MUCH LIGHTER EXCEPT ALONG
THE WARMER LAKE SHORES. STILL...WITH TEMPS FALLING TO THE TEENS
BELOW ZERO MONDAY NIGHT FOR THE INTERIOR WEST AND CENTRAL...A WIND
CHILL ADVISORY MAY BE NEEDED WITH CHILLS DOWN TO -30F.
WEDNESDAY INTO SATURDAY...YET ANOTHER POTENT CLIPPER WILL PUSH
SOUTHEAST RIGHT OVER THE CWA WEDNESDAY MORNING INTO THE AFTERNOON. A
QUICK ROUND OF MODERATE SNOW IS POSSIBLE FOR MUCH OF THE CWA
WEDNESDAY MORNING WITH IMPRESSIVE Q-VECTOR CONVERGENCE AND UPPER PV
ANOMALY. THE GFS HAS BEEN THE OUTLIER WITH THIS SYSTEM...SO HAVE
TRENDED WITH THE ECMWF AND GEM. BEHIND THE SYSTEM...INCREASING N TO
NE GRADIENT FLOW BETWEEN A LAGGING 1020 MB LAKE-INDUCED TROUGH AND
IMPINGING 1044 MB HIGH WILL BRING A POSSIBLY INTENSE BOUT OF LAKE
ENHANCED SNOW TO NORTH-CENTRAL UPPER MI. HAVE BUMPED UP POPS
CONSIDERABLY...AND LATER SHIFTS WILL NEED TO MONITOR MODEL TRENDS AS
HEADLINES WILL BE POSSIBLE WEDNESDAY AFTERNOON AND EVENING ALONG
LAKE SUPERIOR.
TEMPS CONTINUE TO REMAIN WELL BELOW NORMAL INTO THURSDAY AFTER
ANOTHER SHOT OF -25C H8 TEMPS WEDNESDAY AFTERNOON. DID NOT DEVOTE
MUCH TIME TO THE FORECAST BEYOND WEDNESDAY GIVEN MODEL DISAGREEMENT
AT THIS TIME...THOUGH WEIGHTED THE FORECAST TOWARD THE MORE
CONSISTENT ECMWF. INDICATIONS ARE THAT ANOTHER POTENT TROUGH AND
ACTIVE FEW DAYS OF WX WILL AFFECT THE AREA FRIDAY INTO SATURDAY
MORNING...WITH PERSISTENT LES FOR WNW SNOW BELTS THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1234 PM EST SAT JAN 18 2014
ARRIVAL OF DRIER LLVL AIR SHOWN ON 12Z INL RAOB UNDER SFC HI PRES
RDG WL RESULT IN PREDOMINANT VFR CONDITIONS AND LGT WINDS THRU THIS
EVNG. BUT SW WINDS WL BE INCRSG LATER TNGT AS PRES GRADIENT SHARPENS
TO THE S OF DEEPENING LO PRES TRACKING THRU ONTARIO. SN WL ALSO DVLP
BY THE EARLY MRNG HRS ON SUN AT IWD/CMX AHEAD OF APRCHG ATTENDANT
COLD FNT. THE COMBINATION OF THE FALLING AND BLSN WHIPPED UP BY THE
GUSTY WINDS WL LEAD TO IFR VSBYS...ESPECIALLY AT THE MORE EXPOSED
CMX LOCATION...WHERE LIFR CONDITIONS ARE LIKELY. DOWNSLOPE NATURE OF
THE EXPECTED WSW FLOW WL LIKELY MAINTAIN VFR WX AT SAW. STRONG
SUBSIDENCE AND DIMINISHING WINDS IN THE WAKE OF COLD FROPA ON SUN
MRNG SHOULD LIMIT THE INTENSITY OF LES/BLSN...BUT IFR VSBYS ARE
LIKELY TO PERSIST AT CMX. WSHFT TO A MORE UPSLOPE NNW DIRECTION WL
LEAD TO MVFR CONDITIONS AT SAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST SAT JAN 18 2014
RELATIVELY LIGHT WINDS EARLY THIS EVENING WILL GIVE WAY TO A WSW
GALE OVER MUCH OF CENTRAL AND EASTERN LAKE SUPERIOR OVERNIGHT AS THE
PRES GRADIENT TIGHTENS OVER THE UPPER LAKES S OF DEEPENING LO PRES
CROSSING ONTARIO. THE GALES WILL VEER TO THE NW ON SUN MORNING
FOLLOWING A COLD FRONTAL PASSAGE...BUT THE WINDS WILL TEND TO
DIMINISH TO 25-30 KTS DURING THE AFTERNOON WITH ARRIVAL OF WEAKER
PRES GRADIENT AHEAD OF APPROACHING HI PRES IN THE NORTHERN PLAINS.
DESPITE THE WEAKENING WINDS...ARRIVAL OF VERY COLD ARCTIC AIRMASS
WILL RESULT IN SOME HEAVY FREEZING SPRAY IN THE AFTERNOON OVER ABOUT
THE E HALF...SO STARTED THE HEAVY FREEZING SPRAY WARNING FOR THIS
AREA AT 18Z SUN. GOING GALE HEADLINE LOOKS TO BE IN GOOD SHAPE.
PERSISTENT NW FLOW OF 20 TO 30 KNOTS WILL CONTINUE THROUGH MONDAY
NIGHT BEFORE WINDS BACK AND WEAKEN IN RESPONSE TO THE NORTHERN
EXTENT OF A SFC RIDGE TUESDAY INTO TUESDAY NIGHT. A POTENT SYSTEM
TRACKING SE OVER UPPER MI WEDNESDAY MAY BRING N TO NE GALES ACROSS
MUCH OF THE LAKE WEDNESDAY AFTERNOON AND NIGHT. ANOTHER WEAK RIDGE
WILL DIMINISH AND BACK WINDS TO THE SW ON THURSDAY. THEN...SW GALES
TO 35 KNOTS WILL BE POSSIBLE THURSDAY NIGHT INTO FRIDAY AHEAD OF
ANOTHER STRONG TROUGH ACROSS SOUTH CENTRAL CANADA. 20 TO 30 KNOTS
WILL CONTINUE THROUGH SATURDAY WHILE VEERING TO THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM SUNDAY TO 7 AM EST
TUESDAY FOR LSZ251-267.
GALE WARNING FROM 11 PM THIS EVENING TO 4 PM EST SUNDAY FOR
LSZ249>251-266-267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM SUNDAY TO 7 PM EST
TUESDAY FOR LSZ249-250-266.
HEAVY FREEZING SPRAY WARNING FROM 7 PM SUNDAY TO 1 PM EST
TUESDAY FOR LSZ244-245-248-264-265.
GALE WARNING FROM 11 PM THIS EVENING TO 7 AM EST SUNDAY FOR
LSZ265.
GALE WARNING FROM 8 PM THIS EVENING TO 7 AM EST SUNDAY FOR
LSZ242>245-263-264.
HEAVY FREEZING SPRAY WARNING FROM 7 PM SUNDAY TO 7 AM EST
TUESDAY FOR LSZ243-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...KC
MARINE...KC/KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
553 PM CST SUN JAN 19 2014
.UPDATED FOR 00Z AVIATION DISCUSSION...
ISSUED AT 541 PM CST SUN JAN 19 2014
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 318 PM CST SUN JAN 19 2014
TEMPERATURES HAVE WARMED BEYOND EXPECTATIONS DESPITE DEEP SNOW
COVER THANKS TO A MUCH SLOWER PROGRESSION OF CLOUD COVER FROM THE
NORTH AND SOMEWHAT DECENT MIXING. THE CLOUD SHIELD ACROSS NORTHERN
MN/WI SHOULD BEGIN TO ACCELERATE SOUTHWARD THIS EVENING AFTER
SUNSET AS WINDS ALSO BECOME NORTHWEST. LOW LEVEL MOISTURE BELOW
THE DGZ WILL ALLOW FOR PATCHY DRIZZLE OR FREEZING DRIZZLE EARLY
BEFORE THE MOISTURE DEPTH INCREASES DURING THE LATE EVENING. LIGHT
SNOW WOULD THEN BE THE PRECIP OF CHOICE THROUGH MONDAY AFTERNOON.
ACCUMULATIONS OF SNOW AND ICE ARE EXPECTED TO BE MINIMAL...BUT
AROUND A HALF INCH OF SNOW IS POSSIBLE ACROSS SOUTHWESTERN MN
WHERE A VORT MAX WILL ENHANCE THE LIFT THERE MONDAY. TEMPERATURES
WILL DROP INTO THE SINGLE DIGITS AND TEENS LATE TONIGHT...AND
CONTINUE TO FALL THROUGHOUT MONDAY TO AROUND ZERO BY EARLY MONDAY
EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 PM CST SUN JAN 19 2014
SNOW COMES TO AN END BY MONDAY EVENING AS A BROAD AREA OF SURFACE
HIGH PRESSURE SETTLES INTO THE UPPER MIDWEST. CLOUD COVER IS
EXPECTED TO DIMINISH NOTABLY AFTER MIDNIGHT MONDAY NIGHT...WHICH
SHOULD ALLOW TEMPERATURES TO PLUMMET INTO THE 15 TO 25 BELOW RANGE
ACROSS MOST OF CENTRAL/SOUTHERN MN AND WESTERN WI. THE GFS GUIDANCE
IS THE COLDEST AMONGST THE SOLUTIONS...AND INDICATES 30 BELOW READINGS
ACROSS WEST CENTRAL/CENTRAL MN. HOWEVER...GIVEN THE RECENT COLD BIAS
OF THE GFS...WILL LEAN TOWARD THE MORE CONSERVATIVE CONSENSUS WITH
THE COLDEST MINIMUMS NEAR 25 BELOW NEAR ALEXANDRIA/LITTLE FALLS.
WHILE WINDS WILL ALSO BE TRENDING DOWNWARD...SPEEDS APPEAR TO STAY
AROUND 5-8KTS. SAID WINDS COMBINED WITH THE EXPECTED TEMPERATURES
COULD LEAD TO MINIMUM WIND CHILL VALUES FROM 25 TO 40 BELOW.
ANTICIPATE THE AREA TO BE UNDER A WIND CHILL ADVISORY AT A
MINIMUM...WITH A WARNING POTENTIALLY NEEDED ACROSS WEST CENTRAL MN.
COOL SURFACE HIGH PRESSURE PREVAILS ON TUESDAY...WITH READINGS
STRUGGLING TO MODERATE INTO THE SINGLE DIGITS ABOVE ZERO. BY LATE
TUESDAY AFTERNOON...THERE IS DECENT MODEL AGREEMENT THAT SHORTWAVE
ENERGY ON THE WESTERN PERIPHERY OF THE HUDSON BAY LOW WILL PIVOT
ACROSS THE FORECAST AREA. EXPECT LIGHT SNOW TO BEGIN DURING THE
TUESDAY P.M. RUSH HOUR...AND PERSIST INTO WEDNESDAY. SNOW
ACCUMULATIONS OF A DUSTING TO 2 INCHES APPEAR LIKELY. A SECONDARY
BLAST OF COLD AIR ARRIVES ON WEDNESDAY NIGHT...WITH LOWS DIPPING TO
BETWEEN 10 AND 20 BELOW. THIS WILL MOST LIKELY BE ANOTHER TIME FRAME
WITH WIND CHILL HEADLINES.
A TROUGH OF LOW PRESSURE SINKING DOWN FROM THE NORTH WILL SUPPRESS
THE RIDGE TO THE SOUTHERN CONUS LATE IN THE WEEK...AND ALLOW
TEMPERATURES TO MODERATE INTO THE 20S ON FRIDAY. HOWEVER...THE
MODEST WARM-UP WILL BE ACCOMPANIED BY LIGHT SNOW CHANCES...AS THE
AFOREMENTIONED NORTHERN STREAM SHORTWAVE PLUNGES SOUTH ACROSS THE
AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 541 PM CST SUN JAN 19 2014
RH FORECASTS FROM BOTH THE NAM AND RAP INDICATE THAT THE MVFR/IFR
CLOUDS WILL CONTINUE TO SLIDE SOUTHWARD OVERNIGHT. CONFIDENCE IN
FREEZING DRIZZLE IS LOW...SO HAVE REMOVED IT FROM THE TAFS. TWO
WAVES WILL MOVE ACROSS THE REGION. THE FIRST WILL BRING LIGHT SNOW
MAINLY TO THE NORTHEAST SITES...WHILE THE SECOND STRONGER WAVE
WILL BRING SNOW ALONG THE MISSOURI RIVER VALLEY...AND COULD AFFECT
KRFW. CIGS SHOULD LIFT TO VFR BY LATE MONDAY AFTERNOON.
KMSP...
THE TWO WAVES THAT ARE RESPONSIBLE FOR GENERATING THE PRECIP WILL
PRETTY MUCH SPLIT THE METRO...SO NOT ANTICIPATING MUCH FOR IMPACTS
ON THE SNOWFALL OVER THE NEXT 24 HOURS. CEILINGS WILL CONTINUE TO
BE A CHALLENGE...AND VARY FROM VFR...DOWN TO BELOW THE CRITICAL
1700 THRESHOLD. THEY SHOULD CONSISTENTLY IMPROVE BY MONDAY
AFTERNOON.
/OUTLOOK FOR KMSP/
TUE...VFR...WITH MVFR/IFR CIGS/-SN LATE. WINDS W-SW 5KTS.
WED...-SN EARLY...THEN VFR. WINDS NNW 10G20KTS.
THU...VFR. WINDS WNW AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...BORGHOFF
LONG TERM...LS
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
348 PM CST SAT JAN 18 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 348 PM CST SAT JAN 18 2014
WEATHER HAS BEEN QUIETING DOWN QUICKLY IN THE WAKE OF THIS MORNINGS
STRONG CLIPPER. STRONG SUBSIDENCE IN THE WAKE OF THE CLIPPER HAS
HELPED CLEAR SKIES OUT...SAVE FOR A LINGERING ZONE OF FGEN AROUND H7
THAT HAS KEPT AN AREA OF CLOUDS WITH A FEW FLURRIES GOING FROM THE
TWIN CITIES BACK TOWARD EAU...THOUGH EVEN THESE CLOUDS SHOULD SLOWLY
FADE AWAY THIS AFTERNOON.
TONIGHT...WINDS WILL QUICKLY TURN TOWARD THE SW AS A MILD PACIFIC
AIRMASS QUICKLY MOVES INTO THE AREA. WAA OUT AHEAD OF THE WARM NOSE
WILL LEAD TO A BAND OF MAINLY MID LEVEL CLOUDS WORKING BACK ACROSS
THE AREA. HOWEVER...290-295K SFCS OFF THE NAM SHOWING ENOUGH
MOISTURE MAY BE PRESENT FOR ISENTROPIC LIFT IN THE FAR NE CWA TO
GENERATE SOME -SN AS THE WARMER AIRMASS MOVES IN. THIS IS SUPPORTED
BY REFLECTIVITY FORECASTS FROM THE HRRR AND OTHER HI-RES MODELS...SO
INTRODUCED SOME CHANCE POPS FOR THAT...THOUGH ONLY ONE OR TWO TENTHS
OF AN INCH OF SNOW WOULD BE LIKELY IF ANYTHING DOES FALL. THIS WAA
TONIGHT WILL RESULT IN ANOTHER NIGHT OF NON-DIURNAL TEMP
TRENDS...WITH TEMPS LIKELY ALREADY ABOVE 30 OFF THE BUFFALO RIDGE BY
SUNRISE SUNDAY...WITH MOST OF THE MN CWA INTO THE LOW/MID 20S BY THE
START OF THE DAY SUNDAY. THE WARM START MEANS THE MILD DAY STILL
LOOKS TO BE IN PLACE. FOLLOWED MORE THE GEM/ECMWF FOR HIGHS SUNDAY
WITH MOST OF THE AREA GETTING INTO THE LOW/MID 30S. IF YOU WOULD
LIKE TO AVOID THOUGHTS OF NEEDING A VACATION TO A WARMER CLIMATE...I
SUGGEST YOU STOP READING NOW...AS THESE HIGHS SUNDAY WILL NOT BE A
LASTING TREND.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 348 PM CST SAT JAN 18 2014
THE ROLLER COASTER RIDE OF TEMPERATURE TRENDS WILL CONTINUE
THROUGHOUT THE LONG TERM. AN ARCTIC FRONT WILL SAG SOUTH SUNDAY
NIGHT INTO CENTRAL MN AND WI. STEEP LAPSE RATES UP TO ABOUT 3KFT
IN STRONG CAA REGIME AND AN ISOTHERMAL MOIST TEMPERATURE PROFILE
WITHIN THE DGZ BETWEEN 3KFT TO 10KFT SHOULD PROMOTE OCCASIONAL
LIGHT SNOW DEVELOPMENT BEHIND THE FRONT UNTIL DRIER AIR WORKS IN
MONDAY AFTERNOON. BOOSTED POPS INTO THE CATEGORICAL RANGE...BUT
THIS LOOKS LIKE A HIGH CHANCE/LOW PRECIP EVENT WITH SNOWFALL
AMOUNTS REMAINING GENERALLY A HALF INCH OR LESS. THE BEST CHANCE
OF RECEIVING UP TO AN INCH WILL BE ACROSS WESTERN AND SOUTHERN MN
WHERE A VORTICITY MAX SLIDES SOUTHEAST IN ADVANCE OF THE BUILDING
SURFACE RIDGE MONDAY AFTERNOON. THIS WILL ENHANCE THE LIFT ENOUGH
TO GET A BIT MORE ROBUST SNOWFALL.
THE HIGH BUILDS INTO WESTERN MN MONDAY NIGHT. CLEARING SKIES AND
FRESH SNOWFALL WILL EASILY ALLOW FOR A STOUT INVERSION TO SET UP
WHICH SHOULD ALSO DECOUPLE THE WIND. IF THE WIND FULLY
DECOUPLES...TEMPERATURES WILL BE VERY COLD WITH WIDESPREAD 20S
BELOW ACROSS MN /EXCEPT FOR THE TWIN CITIES METRO/ AND TEENS BELOW
ACROSS WI. SOME SPOTS IN CENTRAL MN MAY DROP TO 30 BELOW AGAIN.
FORECASTING TEMPERATURES IN SUCH A SITUATION IS INHERENTLY
DIFFICULT AS LOCATIONS CAN VARY GREATLY WITH ENHANCED LOCAL
INFLUENCES. THEREFORE...CONFIDENCE IS NOT PARTICULARLY HIGH AND IT
IS IMPOSSIBLE TO CONVEY THESE HIGHLY VARIED LOCAL INFLUENCES WITH
MUCH PRECISION IN THE GRIDS. UNLIKE THE LAST COLD OUTBREAK...THE
COLDER MOS NUMBERS MAY NOT BE AS FAR OFF FROM REALITY IN THE
DECOUPLED ENVIRONMENT. TOOK A COMPROMISE OF THE MOS NUMBERS AND
THE BIAS CORRECTED MOS NUMBERS FOR TEMPS HOPING SPLITTING THE
DIFFERENCE WILL SUFFICE.
BY TUESDAY NIGHT...A WEAK DISTURBANCE WILL DROP SOUTHEAST INTO THE
GREAT LAKES. WITH IT WILL COME A NOSE OF WARMER AIR IN OVERNIGHT
AND A CHANCE OF SNOW ACROSS MUCH OF THE AREA.
THE NEXT ARCTIC FRONT WILL ARRIVE WEDNESDAY AND ANOTHER POLAR HIGH
WILL BUILD INTO THE DAKOTAS AND MINNESOTA WEDNESDAY NIGHT. IT WILL
BE A NEARLY IDENTICAL SET UP TO MONDAY NIGHT AND THE LOW TEMP GRID
IS QUITE SIMILAR AS WELL.
SOME UNCERTAINTY HAS BEEN INTRODUCED BY THE MIDDLE OF NEXT WEEK
WITH THE GFS SHOWING A MUCH MILDER SOLUTION COMPARED TO PREVIOUS
DAYS RUNS. IT SHOWS THE TROUGH BEING CONFINED TO NEW ENGLAND AND
AN EXPANSIVE ZONAL FLOW/WEAK RIDGING ACROSS THE REST OF THE CONUS.
PREFER THE MORE STABLE ECMWF SHOWING A CONTINUATION OF A SERIES OF
POLAR FRONTS THROUGH DAY 10. NOT SEEING MUCH TO INDICATE THE
CURRENT PATTERN WILL CHANGE AND GIVEN HOW LONG IT HAS PERSISTED
THIS WINTER...IT WILL TAKE QUITE A BIT MORE CONVINCING BEFORE A
CHANGE IN DIRECTION IS NECESSARY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1147 AM CST SAT JAN 18 2014
SNOW HAS ALL BUT MOVED OUT OF THE AREA WITH SKIES CLEARING IN THE
SUBSIDENCE IN THE WAKE OF THE LOW THAT IS NOW NEAR DSM. THOSE VFR
CONDITIONS WILL PREVAIL THROUGH MOST OF THIS TAF PERIOD AS ALL
MODELS SHOW STRIP OF MVFR CIGS OVER THE DAKOTAS NOT SURVIVING OUR
DRY AIR AS IT PUSHES EAST. NEXT ARCTIC COLD FRONT WILL BEGIN
SAGGING SOUTHWEST INTO THE MPX AREA AROUND 18Z SATURDAY...WITH
MVFR CIGS LIKELY RETURNING FOR A BIT IN ITS WAKE...THOUGH BETTER
CHANCES FOR MVFR CIGS LOOKS TO COME JUST AFTER THIS TAF PERIOD.
KMSP...HIGH CONFIDENCE IN TAF OVERALL. MODELS SHOW MVFR CIGS OVER
THE DAKOTAS TRACKING ACROSS NRN MN TONIGHT...WITH NOTHING MORE
THAN AN INCREASE IN MID LEVEL CLOUDS TONIGHT AS WARM BUBBLE FOR
SUNDAY MOVES IN. MAY SEE MVFR CIGS RETURN AT THE END OF THE
TAF...BUT CONFIDENCE TO LOW TO INCLUDE AT THIS TIME.
/OUTLOOK FOR KMSP/
MON...CHANCE MVFR/SN THRU MORNING. WINDS N 10KTS.
TUE...VFR. CHANCE MVFR CIGS/-SN TUE NIGHT. WINDS W-SW 5KTS.
WED...VFR. WINDS NW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
901 PM MST Sun Jan 19 2014
.UPDATE...
Tonight...A weak disturbance is moving through the northwest flow
aloft and an associated cold front moved through the northern zones
and pushed into the central. This front is dry and the main effect
will be cooler temperatures tonight and tomorrow. Updated to lower
low temps for tonight across the northern and southern zones. Also
freshened pops and wx. Zelzer
&&
.AVIATION...
UPDATED 2345Z.
VFR conditions will prevail at all sites through the TAF period. Mid
level clouds and breezy conditions will taper off by 06Z. Mercer
&&
.PREV DISCUSSION...
/ISSUED 445 PM MST Sun Jan 19 2014/
Tonight through Tuesday...Overall pattern remains unchanged with a
strong upper ridge over the west coast and dry northwest flow
aloft. Models move a weak short wave embedded within the northwest
flow aloft through the area late this evening. Surface winds will
shift to the north for a few hours. The RUC and the European
models develop light qpf near the Little Belts as a result of this
weak upslope flow. HRRR analysis also develops qpf in this area
for a few hours late this evening. Have gone with low pops to
support this possibility. The surface gradient is not as tight on
Monday allowing for lighter winds. Monday and Tuesday will
continue dry with a northerly flow aloft. Temperatures will remain
above seasonal averages.
Tuesday night through Sunday...The main change in the extended
period was to increase the chances for rain/snow Wednesday into
Wednesday night...as both the EC/GFS continue to show an upper
level disturbance moving southward through the region. There looks
to be a bit more moisture with this disturbance...thus pops have
been increased...especially in the mountains around Kings Hill.
Snow accumulations still look to be on the low side...with most
lower elevation locations only seeing around 1 inch of
snowfall...and about 2 to 3 inches in the mountains. After this
disturbance moves through little to no precipitation is expected
from Thursday through Sunday. Temperatures will cool a bit
Wednesday as the disturbance moves through the region...with high
temperatures likely in the morning and then falling in the
afternoon. It will be cold Wednesday night as skies clear out a
bit...and with the possible fresh snow cover...temperatures will
fall rather quickly early Thursday morning. Otherwise...expect
afternoon temperatures to generally be about 5 to 10 degrees above
normal starting as early as Thursday afternoon and then continuing
into next weekend. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 24 46 29 51 / 0 0 0 0
CTB 19 44 24 47 / 0 0 0 0
HLN 23 43 24 46 / 0 0 0 0
BZN 20 39 19 42 / 0 0 0 0
WEY 7 32 8 33 / 0 0 0 0
DLN 22 41 23 45 / 0 0 0 0
HVR 20 35 20 40 / 0 0 0 0
LWT 23 39 25 44 / 0 0 0 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 11 AM MST Monday Liberty.
&&
$$
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www.facebook.com/US.NationalWeatherService.GreatFalls.gov
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
445 PM MST Sun Jan 19 2014
Update to Aviation
.DISCUSSION...
Tonight through Tuesday...Overall pattern remains unchanged with a
strong upper ridge over the west coast and dry northwest flow
aloft. Models move a weak short wave embedded within the northwest
flow aloft through the area late this evening. Surface winds will
shift to the north for a few hours. The RUC and the European
models develop light qpf near the Little Belts as a result of this
weak upslope flow. HRRR analysis also develops qpf in this area
for a few hours late this evening. Have gone with low pops to
support this possibility. The surface gradient is not as tight on
Monday allowing for lighter winds. Monday and Tuesday will
continue dry with a northerly flow aloft. Temperatures will remain
above seasonal averages.
Tuesday night through Sunday...The main change in the extended
period was to increase the chances for rain/snow Wednesday into
Wednesday night...as both the EC/GFS continue to show an upper
level disturbance moving southward through the region. There looks
to be a bit more moisture with this disturbance...thus pops have
been increased...especially in the mountains around Kings Hill.
Snow accumulations still look to be on the low side...with most
lower elevation locations only seeing around 1 inch of
snowfall...and about 2 to 3 inches in the mountains. After this
disturbance moves through little to no precipitation is expected
from Thursday through Sunday. Temperatures will cool a bit
Wednesday as the disturbance moves through the region...with high
temperatures likely in the morning and then falling in the
afternoon. It will be cold Wednesday night as skies clear out a
bit...and with the possible fresh snow cover...temperatures will
fall rather quickly early Thursday morning. Otherwise...expect
afternoon temperatures to generally be about 5 to 10 degrees above
normal starting as early as Thursday afternoon and then continuing
into next weekend. Brusda
&&
.AVIATION...
UPDATED 2345Z.
VFR conditions will prevail at all sites through the TAF period. Mid
level clouds and breezy conditions will taper off by 06Z. Mercer
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 26 46 29 51 / 0 0 0 0
CTB 20 44 24 47 / 0 0 0 0
HLN 23 43 24 46 / 0 0 0 0
BZN 20 39 19 42 / 0 0 0 0
WEY 7 32 8 33 / 0 0 0 0
DLN 22 41 23 45 / 0 0 0 0
HVR 22 35 20 40 / 0 0 0 0
LWT 23 39 25 44 / 0 0 0 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
315 PM CST SAT JAN 18 2014
.UPDATE...
UPDATED TO ALLOW HIGH WIND WARNING EXPIRE.
&&
.DISCUSSION...
MOST SUSTAINED AND HIGH WIND GUSTS HAVE DROPPED BELOW HIGH WIND
WARNING CRITERIA...THUS ALLOWED TO EXPIRED AND HAVE THE WIND
ADVISORY GOING UNTIL 6PM.
&&
.PREV DISCUSSION... /ISSUED 1253 PM CST SAT JAN 18 2014/
UPDATE...
MAIN UPDATES WERE TO INCREASE WINDS AND ISSUE A HIGH WIND WARNING
FOR PARTS OF THE AREA.
DISCUSSION...
BY 1030AM...WE WERE STARTING TO GET A FEW HIGH WIND GUSTS AND
BASED ON EXPECTED STRENGTHENING DURING THE LATE
MORNING...FAVORABLE MOMENTUM TRANSFER OF WINDS ALOFT/STEEP LAPSE
RATES AND CONTINUED HIGH WINDS IN THE AFTERNOON...ISSUED A HIGH
WIND WARNING FOR SEVERAL COUNTIES IN NORTHEAST AND EAST CENTRAL
NEBRASKA. THE H9 WINDS SHOWED A LARGE AREA OF 50 TO 55KTS WINDS IN
THIS AREA AND THE RAP/HRRR WERE ALSO SUPPORTIVE OF HIGH WIND GUST.
THE LATEST HRRR IS EVEN A BIT MORE WIDESPREAD WITH THE STRONGER
WINDS.
AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
STRONG WINDS WILL BE THE PRIMARY AVIATION CONCERN THROUGH 00Z WITH
SUSTAINED WINDS OF 25-35KTS G40-50KTS. THE WINDS WILL SUBSIDE BY
00Z AND FURTHER DIMINISH TO UNDER 10KTS BY 03Z. THE BULK OF THE
PRECIP WAS TO THE SOUTH OF THE TAF SITES...WITH VFR CIGS
FL040-050. DO HAVE PERIODS OF MVFR CIGS ESPECIALLY AT KOFK AND
KOMA THROUGH THE AFTERNOON FL015-030.
PREV DISCUSSION... /ISSUED 337 AM CST SAT JAN 18 2014/
DISCUSSION...
THE MAIN FORECAST CONCERNS ARE THE WIND EVENT TODAY AND THEN NEAR
RECORD TEMPERATURES ON SUNDAY.
EARLY MORNING WATER VAPOR IMAGERY INDICATED A SMALL BUT POTENT
SHORTWAVE TROUGH OVER NE SD. THIS SYSTEM WAS ASSOCIATED WITH
AROUND 100 M H5 HEIGHT FALLS. THE ASSOCIATED 998 MB SURFACE LOW
ON THE 09Z OBJECTIVE SURFACE ANALYSIS WAS LOCATED OVER EXTREME SE
ND. THE UPPER LEVEL SYSTEM AND ASSOCIATED SFC LOW WILL BE DROPPING
SOUTH TODAY ACROSS SW MN EARLY THIS MORNING...AND THEN THROUGH
IOWA THIS AFTERNOON. CONSISTENT WITH PREVIOUS SYSTEM THIS
WEEK THE LARGE-SCALE FORCING FOR ASCENT AND MEASURABLE PRECIP
WILL MISS OUR FA TO THE EAST...BUT OUR CWA WILL ONCE AGAIN BE IN A
FAVORABLE LOCATION FOR STRONG WINDS. MODELS ALL REMAIN CONSISTENT
IN THE 7-8 MB 3 HR SURFACE PRESSURE RISES /CURRENTLY OVER NORTHERN
ND/ WILL PUSH INTO THE FA THROUGH THE MORNING AS THE SURFACE
LOW MOVES INTO IOWA. THE 850 AND 925 MB WINDS INCREASE TO 50-55
AND 40-45 KT RESPECTIVELY. THIS ALONG WITH STEEPING LOW LEVEL
LAPSE RATES WILL ALLOW FOR STRONG WINDS TO MIX TO THE SURFACE.
PREVIOUSLY ISSUED WIND ADVISORY FOR THE ENTIRE CWA LOOKS GOOD. WE
MAY SEE A COUPLE OF LOCATIONS /SUCH AS OFK-BVN-OLU/ FLIRT WITH
HIGH WIND WARNING FOR AN HOUR WITH WIND GUSTS AS THE BEST PRESSURE
RISES MOVE THROUGH. WILL HAVE SOME GUSTS TO 48 KT FOR THESE
LOCATIONS BUT WIDESPREAD WRNG CRITERIA WINDS ARE NOT EXPECTED. AS
WITH THE THURSDAY SYSTEM...WE WILL LIKELY SEE ISO-SCT SNOW SHOWERS
DEVELOP WITH THE STEEP LOW-LEVEL LAPSE RATES AND SMALL POSITIVE
AREA IN POINT FORECAST SOUNDINGS. WE DO NOT EXPECT ANY
ACCUMULATION OR BLOWING SNOW ISSUES HERE...BUT WILL MAINTAIN THESE
SMALL POPS THROUGH EARLY AFTERNOON BEFORE THE SOUNDINGS START TO
STABILIZE.
THE CONDITIONS WILL QUIET RAPIDLY BY LATE AFTERNOON AND THE WIND
ADVISORY MAY BE ABLE TO BE CANCELLED EARLIER THAN ITS CURRENT 6
PM TIME FRAME AS THE SYSTEM SHIFTS EAST AND THE LOW LEVEL FLOW
BACKS TO THE WEST. THIS SHOULD SET UP A VERY FAVORABLE PATTERN FOR
WARMING ON SUNDAY. MODELS CONTINUE TO INITIALIZE WITH SNOW COVER
OVER THE ERN 2/3 OF THE FA AND THIS IS IN ERROR AND THUS GRIDDED
AND MOS PRODUCTS ARE WAY TO COOL WITH TEMPERATURES. MIXING TO
AROUND 925 MB PRODUCED HIGHS IN THE 60S WEST AND 50S EAST. WE WILL
LIKELY FALL SHORT OF RECORDS AT ALL 3 SITES THOUGH BUT STILL WELL
ABOVE NORMAL.
TEMPERATURES ARE THE MAIN FORECAST CONCERN THROUGH THE EXTENDED
PERIOD AS A BACK DOOR COLD FRONT PUSHES INTO THE FA ON MONDAY. THE
MODELS ARE A TOUCH SLOWER WITH THIS FRONT THAN PREVIOUS RUNS AND
THUS WE MAY SEE TEMPERATURES WARM THROUGH THE FIRST HALF OF MONDAY
BEFORE FALLING IN THE AFTERNOON. THUS WE HAVE INCREASED HIGHS
MOST AREAS FOR MONDAY. BOTH THE NAM AND GFS ADVERTISE STRONG 925
MB FRONTOGENESIS AS THIS BOUNDARY SLIDES INTO THE FA AND THIS MAY
ALLOW FOR SOME LIGHT SNOW SHOWERS AGAIN LATE MONDAY AFTERNOON IN
THE NORTH...CONTINUING INTO THE EVENING HOURS BUT AGAIN WE DO NOT
EXPECT ACCUMULATIONS. THIS BOUNDARY WILL OSCILLATE ACROSS THE FA
THROUGH THE REST OF THE EXTENDED. WED NIGHT AND THU LOOK TO BE THE
COLDEST PERIODS OF THE EXTENDED BEFORE TEMPERATURES START TO
MODERATE TOWARD NEXT WEEKEND.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011-012-015>018-
030>034-042>045-050>053-065>068-078-088>093.
IA...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043-055-056-069-
079-080-090-091.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
323 PM EST SAT JAN 18 2014
.SYNOPSIS...
A SERIES OF DISTURBANCES IN THE JET STREAM WINDS ALOFT AND
ASSOCIATED COLD FRONTS WILL PRODUCE PERIODS OF SNOW SHOWERS ALONG
WITH MUCH COLDER TEMPERATURES BY EARLY THIS UPCOMING WEEK.
OVERALL...SNOW ACCUMULATIONS WILL BE LIGHT WITH BEST CHANCES OF A
COUPLE INCHES OCCURRING ACROSS THE ADIRONDACK MOUNTAINS OF NEW YORK
AND NORTHERN GREEN MOUNTAINS OF VERMONT. TEMPERATURES WILL BE ABOVE
NORMAL AGAIN ON SUNDAY...BUT FALL BETWEEN 10 AND 20 DEGREES BELOW
NORMAL BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 320 PM EST SATURDAY...FCST CHALLENGE TONIGHT WL BE AREAL
COVERAGE/INTENSITY OF SNOW...ALONG WITH CLOUDS AND IMPACTS ON
TEMPS. WATER VAPOR SHOWS POTENT 5H VORT DRIVING ACRS THE OHIO
VALLEY WITH MID LVL MOISTURE STREAMING AHEAD OF SYSTEM ACRS
CENTRAL/WESTERN NY/PA ATTM. HOWEVER...SATL PICS SHOW CLOUDS
INCREASING ACRS THIS REGION...BUT OBSERVATIONS SHOW LIMITED
MOISTURE/SNOW REACHING THE GROUND...INDICATING VERY DRY LLVLS.
THIS WL BE OUR FCST PROBLEM TONIGHT. HIGH RESOLUTION BTV4KM...RAP
13...AND 15Z HRRR MODEL SHOW WEAK INVERTED TROF LIKE FEATURE WITH
SOME LEFTOVER MID LVL MOISTURE/LIFT MOVING FROM SOUTH TO NORTH
ACRS OUR CWA BTWN 02Z-08Z TONIGHT. IN ADDITION...925MB TO 850MB
WINDS BECOME NORTHWEST WHICH WL HELP ENHANCE LLVL
LIFT/MOISTURE...BUT OVERALL QPF IS VERY LIGHT <.10" WITH GREATEST
FOCUS ACRS THE NORTHERN DACKS AND CENTRAL GREEN MTNS. WL MENTION
LIKELY POPS OVERNIGHT IN THE MTNS...AND JUST CHC POPS IN THE
VALLEYS WITH A DUSTING TO 1 INCH POSSIBLE. BASED ON GOOD OMEGA/RH
AND SNOW GROWTH PROFILES...WOULD NOT BE SURPRISED OF A DUSTING OR
SO OVERNIGHT AT BTV. TEMPS WL HIGHLY DEPEND UPON
CLOUDS/PRECIP...BUT WL TREND WARMER BASED ON PROGGED RH
FIELDS...L20S MTN VALLEYS TO M/U 20S ELSEWHERE. OTHERWISE...RAP 13
SHOWS BETTER 1000 TO 500 MB RH >70% APPROACHING OUR WESTERN CWA BY
10Z SUNDAY...ASSOCIATED WITH NEXT CLIPPER SYSTEM. WL INCREASE POPS
ACRS OUR WESTERN CWA TWD SUNRISE...BUT BETTER PRECIP CHCS ARRIVE
ON SUNDAY.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 356 AM EST SATURDAY...NE CONUS WL BE IN TRANSITION FROM ABOVE
NORMAL TEMPS TO DEVELOPING DEEP MID/UPPER LVL TROF WITH MUCH BLW
NORMAL TEMPS ANTICIPATED BY EARLY THIS UPCOMING WEEK. NAM/GFS ARE
IN GOOD AGREEMENT WITH LARGE SCALE FEATURES...AND SHOW SYSTEMS WL
BE COMING IN PIECES. BOTTOM LINE WL BE EACH EMBEDDED 5H VORT AND
ASSOCIATED SFC TROF WL HAVE LESS AND LESS AVAILABLE MOISTURE TO
WORK WITH...ESPECIALLY AS ARCTIC AIR BECOMES ESTABLISHED BY
MONDAY. IN ADDITION...HAVE NOTED BEST 5H PVA ASSOCIATED WITH
POTENT S/W ENERGY SLIDES TO OUR SOUTH ON SUNDAY...WHILE A RIBBON
OF ENHANCED 850 TO 500MB RH RACES FROM THE NORTHERN OHIO VALLEY
INTO THE NE CONUS. MEANWHILE...BEST LLVL SFC CONVERGENCE WITH
ARCTIC BOUNDARY LAGS ACRS THE NORTHERN LAKES ON SUNDAY AND DOES
NOT ARRIVE UNTIL EARLY MONDAY...WHEN BEST RH IS SHIFTING SOUTH OF
OUR CWA. FOR SUNDAY...WL MENTION LIKELY/CAT POPS ACRS THE
DACKS/SOUTHERN SLV AND PARTS OF THE CENTRAL/NORTHERN GREEN MTNS.
ELSEWHERE WL MENTION CHC/LOW LIKELY POPS BASED ON FAVORABLE 850 TO
500MB RH PROFILES AND SOME WEAK MID LVL LIFT. OVERALL...QPF WL BE
LIGHT...RANGING FROM A COUPLE HUNDREDTHS TO A COUPLE TENTHS ACRS
THE NORTHERN GREENS AND WESTERN DACKS. SNOW ACCUMULATIONS WL BE A
DUSTING TO 2 OR 3 INCHES. HAVE NOTED THE SNOW SQUALL PARAMETER
INCREASES DURING THE AFTN HOURS...THINKING THIS IS A RESULT OF SFC
HEATING AND STEEPENING LLVL LAPSE RATES/INSTABILITY...WHICH HINTS
AT SNOW SHOWER ACTIVITY BECOMING MORE CONVECTIVE IN NATURE. SOME
UNCERTAINTY ON SNOW SQUALLS AS BEST CONVERGENCE/925MB FGEN ARRIVES
AFT 21Z SUNDAY WITH ARCTIC BOUNDARY...THEREFORE WL NOT MENTION
SQUALLS ON SUNDAY...BUT COULD SEE BRIEF MODERATE SNOW SHOWER
ACTIVITY ACRS THE MTNS. THE COMBINATION OF COOLING 925MB TEMPS AND
MORE CLOUDS ANTICIPATED...THINKING HIGHS WL RANGE BTWN M/U 20S
MTNS TO L/M 30S WARMER VALLEYS ON SUNDAY.
SUNDAY NIGHT INTO MONDAY...WELL ADVERTISED ARCTIC BOUNDARY SWINGS
ACRS OUR CWA...WITH RIBBON OF ENHANCED MOISTURE AND STRONG 925MB
FGEN FORCING. IN ADDITION...LOCAL 4KM WRF AND LATEST 12Z NAM SHOW
FAVORABLE CONDITIONS FOR SNOW SQUALLS AS LOCALLY DEVELOPED SNOW
SQUALL PARAMETER IS BTWN 3-5...ESPECIALLY ACRS NORTHERN CWA...WHERE
INSTABILITY/MOISTURE AND WIND FIELDS ARE THE BEST. HOWEVER...STILL
SOME UNCERTAINTY ON AREAL COVERAGE OF SNOW SHOWERS AND POTENTIAL OF
SNOW SQUALLS AS BEST CONVERGENCE/SHARP THERMAL BOUNDARY LAGS
MOISTURE/FORCING. THINKING ANOTHER DUSTING TO LOCALIZED 2 OR 3
INCHES WL BE POSSIBLE ON SUNDAY EVENING...WITH HIGHEST AMOUNTS IN
THE MTNS. AFTER 06Z MONDAY...BEST CONVERGENCE AND MOISTURE QUICKLY
SHIFTS SOUTH OF OUR CWA AND DRIER AIR ADVECTS ON BRISK NORTHWEST
WINDS. A FEW LINGERING UPSLOPE SNOW SHOWERS/FLURRIES WL BE POSSIBLE
BUT OVERALL PRECIP WL BE LIGHT. WL MENTION LIKELY POPS ASSOCIATED
WITH BOUNDARY THRU 06Z...THEN TAPER TO CHC POPS FOR THE MTNS BY 12Z
MONDAY. STRONG LLVL CAA DEVELOPS WITH PROGGED 925MB TEMPS RANGING
BTWN -8C NEAR VSF TO -20C NEAR MSS AT 12Z MONDAY. THESE TEMPS CONT
TO FALL ON MONDAY ON BRISK NORTHWEST WINDS OF 10 TO 20 KNOTS WITH
VALUES BTWN -14C AND -23C BY 00Z TUES. TEMPS WL STRUGGLE IN THE
SINGLE DIGITS SLV/DACKS TO L/M 20S LWR CT RIVER VALLEY ON MONDAY.
MONDAY NIGHT...SFC HIGH PRES AXIS BUILDS INTO OUR CWA...BUT GRADIENT
REMAINS BTWN BUILDING HIGH PRES AND DEPARTING LOW PRES. THIS WL
CREATE BRISK NORTHWEST WINDS...ESPECIALLY IN THE EVENING HRS AND
BITTERLY COLD WIND CHILL VALUES. THINKING WIND CHILL
ADVISORIES/WARNINGS WL PROBABLY BE NEEDED FOR READINGS BTWN -15F TO
-30F. SFC TEMPS WL RANGE BTWN -15 AND -20F SLV/DACKS TO 0F TO -10F
ACRS MOST OF VT...WITH WARMEST VALUES NEAR LAKE CHAMPLAIN AND ACRS
THE LWR CT RIVER VALLEY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 205 PM EST SATURDAY...OVERALL QUIET WEATHER EXPECTED FOR
THE LONG TERM...WITH RIDGING OVER THE NORTH COUNTRY KEEPING
COASTAL LOW AND ASSOCIATED PRECIP FAR TO THE EAST. WITH NW FLOW
FILTERING IN COLDER AIR AS 925MB TEMPS DROP INTO THE -20C TO -28C
RANGE. THIS WILL RESULT IN TUESDAY AND WEDNESDAY MAX TEMPS IN THE
SINGLE DIGITS WITH HIGHER ELEVATIONS SEEING MAX TEMPS NEAR ZERO
OR SLIGHTLY COOLER. TUESDAY NGT AND WEDNESDAY NGT MIN TEMPS WILL
RANGE FROM NEGATIVE TEENS TO NEGATIVE SINGLE DIGITS.
SOME SLGT WARMING PSBL ON THURSDAY AS A WEAKENING SFC LOW MOVES
FROM THE SERN GREAT LAKES TO OUR SOUTH TOWARDS THE
ATLANTIC...KEEPING THE NORTH COUNTRY DRY...BUT ALSO BRINGING A
BRIEF BREAK IN NORTHERLY FLOW. TEMPS ON THURSDAY WILL RANGE FROM
0 TO LOW TEENS DURING THE DAY WITH THURSDAY NGT MINS IN THE
NEGATIVE SINGLE DIGITS.
BEHIND THIS WEAKENING SFC LOW...RIDGING WILL OCCUR AT THE SFC AND
ALOFT. AS THE SFC RIDGE AXIS SHIFTS EAST...BRINGING SOUTHERLY
FLOW TO THE NORTH COUNTRY...TEMPS WILL MODERATE TO THE TEENS ON
FRIDAY...POSITIVE DIGITS FRIDAY NIGHT AND WARMING TO NEAR NORMAL
ON SATURDAY.
EVEN THOUGH THE NORTH COUNTRY WILL GENERALLY BE IN NW FLOW
TUESDAY THROUGH THURSDAY...LACK OF MOISTURE AND STRONG FLOW WILL
INHIBIT POTENTIAL FOR UPSLOPE SNOW SHOWERS. THE NEXT PROBABLE
CHANCE FOR WIDESPREAD PRECIP WILL BE AT THE END OF THE PERIOD
FRIDAY NGT AS AN UPPER LOW BRINGS VORTICITY TOWARDS THE NORTH
COUNTRY FROM THE NW FRIDAY NGT INTO THE WKND.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
THROUGH 18Z SUNDAY...LIGHT FLOW CONTINUES WITH VFR CONDITIONS
THIS AFTN. DRY AIR ACROSS THE NORTH COUNTRY KEEPING MOISTURE AT
BAY...BUT LATE THIS AFTN INTO EARLY EVENING...EXPECT -SHSN TO
AFFECT TERMINALS BRIEFLY. AREAS MOST LIKELY TO SEE -SHSN AND MVFR
CONDITIONS WITHIN -SHSN WILL BE KMSS/KRUT/KMPV AND KSLK. AFTER
03Z...SNOW SHOWERS LOOK TO DIMINISH AS FEATURE TO THE WEST
WEAKENS AND LOW OFF THE NEW ENGLAND COAST SHIFTS NORTHEASTWARD.
EXPECT VFR CONDITIONS AFTER SNOW SHOWERS MOVE OUT...BUT ANY
CLEARING COULD LEAD TO FOG DEVELOPMENT ESP IN LGT FLOW LESS THAN
5KTS.
TOWARDS DAYBREAK...INCREASING CHC FOR -SHSN ESP AT KMSS/KSLK AS
SW FLOW DEVELOPS. ANOTHER SFC LOW PRESSURE SYSTEM WILL APPROACH
FROM THE NW...INCREASING THREAT FOR SHSN ACROSS THE NORTH COUNTRY
AROUND 12Z AND AFTER. WINDS GENERALLY OUT OF THE SOUTH AT
5-10KTS.
OUTLOOK 18Z SUNDAY THROUGH THURSDAY...
18Z SUN THROUGH 12Z MONDAY...VFR WITH SCT MVFR/IFR IN SHSN AS
ARCTIC FRONT PUSHES THROUGH THE AREA. BEST SHSN COVERAGE 18-06Z.
12Z MONDAY ONWARD...MAINLY VFR WITH HIGH PRESSURE.
&&
.EQUIPMENT...
AS OF 400 AM EST SATURDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...KGM
AVIATION...KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
919 AM EST SAT JAN 18 2014
.SYNOPSIS...
THE COMBINATION OF A WEAKENING UPPER DISTURBANCE AND A DEVELOPING
AREA OF LOW PRESSURE OFF THE NEW JERSEY COAST WILL BRING LIGHT
SNOW TO PORTIONS OF THE NORTH COUNTRY TODAY BEFORE TAPERING OFF
TONIGHT. MORE SNOW SHOWERS AND POSSIBLE SNOW SQUALLS ARE EXPECTED
ON SUNDAY AHEAD OF AN ARCTIC COLD FRONT...WHICH WILL MOVE THROUGH
THE REGION SUNDAY NIGHT THROUGH EARLY MONDAY. BITTERLY COLD AIR
WILL FOLLOW THE FRONT FOR ALL OF NEXT WEEK...WITH HIGHS IN THE
SINGLE DIGITS TO LOW TEENS ABOVE ZERO...AND LOWS IN THE SINGLE
DIGITS TO TEENS BELOW.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 905 AM EST SATURDAY...AS STATED BY PREVIOUS FORECASTER THE
CHALLENGE TODAY AND TONIGHT WL BE AREAL COVERAGE/INTENSITY OF
SNOW ASSOCIATED WITH POTENT 5H ENERGY IN THE FLW ALOFT.
UNFORTUNATELY IF YOU ARE LOOKING FOR SNOW TODAY...IT LOOKS LIKE
OUR CWA WL BE SPLIT BTWN TWO SYSTEMS AND STAY MOSTLY
DRY...ESPECIALLY NORTHERN CPV. WATER VAPOR SHOWS 1ST POTENT 5H VORT
WITH ENHANCED COOLING ON IR SATL PIC ACRS WESTERN/CENTRAL NY WITH ANOTHER
IMPRESSIVE 5H VORT LOCATED ACRS CENTRAL NJ THIS MORNING. THE
WESTERN ENERGY AND ENHANCED MID LVL MOISTURE/LIFT WL TRACK FROM
BGM TO SYR TO MSS THIS AFTN...WITH SOME LIGHT SNOW LIKELY ACRS THE
SLV/WESTERN DACKS. CRNT FCST HAS THIS COVERED VERY WELL WITH
LIKELY POPS AND DUSTING TO 2 INCHES. MEANWHILE...2ND VORT WITH
LIGHTNING NOTED ACRS CENTRAL NJ AND SOUTH OF LONG ISLAND WL RACE
NE AND CLIP EASTERN NEW ENGLAND WITH PRECIP. MEANWHILE...OUR CWA
SITS BTWN THESE TWO SYSTEMS WITH LATEST 12Z RAP AND 12Z NAM
SHOWING A RIBBON OF ENHANCED 850 TO 500MB MOISTURE AND 700 TO 500
UVVS FIELDS LOCATED OVER EASTERN NY/WESTERN NEW ENGLAND THIS
MORNING...WEAKENING AS IT LIFTS TWD OUR CWA THIS AFTN/EVENING.
RADAR DOES SHOW WIDESPREAD LIGHT SNOW ASSOCIATED WITH THESE
FEATURES ATTM...AND WL MONITOR TRENDS FOR POSSIBLE IMPACTS ACRS
OUR CENTRAL/SOUTHERN CWA AFT 16Z TODAY...BUT CRNT FCST HAS LIKELY
POPS ACRS RUTLAND/WINDSOR/ORANGE COUNTIES WHICH LOOKS GOOD. WL
WATCH FOR POSSIBLE EXPANSION NORTH THRU THE AFTN BASED ON CRNT
RADAR TRENDS.
OTHERWISE...NEXT POTENT 5H VORT LOCATED ACRS THE WESTERN GREAT
LAKES IMPACTS OUR CWA TONIGHT. ONCE AGAIN LIMITED MOISTURE BUT
GOOD DYNAMICS. MAY NEED TO BUMP POPS UP SLIGHTLY IN A FEW
LOCATIONS...BUT WL EXAMINE 12Z DATA COMPLETELY BEFORE FINAL
DECISION. TEMPS ARE ALL OVER THE PLACE THIS MORNING...BUT SHOULD
RANGE IN THE MID/UPPER 20S MTNS TO L/M 30S VALLEYS. CLOUDS/PRECIP
THIS AFTN WL IMPACT HIGHS ACRS THE SLV AND SOUTHERN VT ZNS.
AS HAS BEEN THE CASE OVER THE LAST FEW DAYS...LATEST RUC/RAP AND
LOCAL 6KM WRF (ALSO RUC BASED) HAVE HANDLED THE FIRST 18 HOURS OF
THE FORECAST VERY WELL DUE TO INITIALIZATION INCLUDING LATEST
SATELLITE AND RADAR DATA...AND THE SAME GOES FOR TODAY. THUS HAVE
LEANED ON THEM HEAVILY FOR THE NEAR TERM FORECAST. OVERALL SYNOPTIC
SETUP FEATURES A WEAKENING MID-LEVEL SHORTWAVE OVER THE OHIO
RIVER VALLEY THIS MORNING...WHILE SURFACE LOW PRESSURE IS
BEGINNING TO DEVELOP OFF THE NJ COAST. AS BOTH OF THESE FEATURES
SHIFT NORTH/NORTHEAST THE BTV CWA IS BASICALLY SQUEEZED BETWEEN
THE 2 SYSTEMS WITH MOISTURE TO OUR SOUTHWEST AND SOUTHEAST AND
GENERALLY DRY SURFACE TO MID-LEVEL AIR IN-BETWEEN AS IS EVIDENT
BY CURRENT CLEAR SKIES ON REGIONAL IR. PRECIP ASSOCIATED WITH THESE
FEATURE DOES FILTER INTO PORTIONS OF THE FORECAST AREA TODAY
THOUGH...MAINLY ACROSS THE ST. LAWRENCE VALLEY AND SOUTHEASTERN
VERMONT DURING THE MID-MORNING HOURS...BUT AREAS IN-BETWEEN WILL
LIKELY SEE LITTLE THROUGH THE DAY UNDER PARTLY TO MOSTLY CLOUDY
SKIES. WHERE PRECIP DOES FALL...IT`LL BE IN THE FORM OF SNOW AND
WE`LL SEE SOME LIGHT ACCUMULATIONS OF GENERALLY 1-3". HIGHS TODAY
WILL REMAIN ON THE MILD SIDE OF NORMAL...WARMEST WHERE MORE
SUNSHINE WILL BE POSSIBLE IN THE CHAMPLAIN VALLEY AND NORTHERN
VERMONT...GENERALLY LOWER TO MID 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS OF 356 AM EST SATURDAY...FOR TONIGHT...AFOREMENTIONED
SHORTWAVE AND COASTAL LOW SHIFT NORTHWARD ENOUGH TO SPILL SOME
MOISTURE INTO CENTRAL PORTIONS OF THE FORECAST AREA BUT BY THAT
TIME THE DEEPEST MOISTURE IS OFFSHORE AND TO OUR NORTHWEST SO
HAVE ONLY OFFERED CHANCE POPS WITH A DUSTING TO POSSIBLY AN INCH
OF ADDITIONAL ACCUMULATION ACROSS THE ENTIRE AREA. BEST CHANCE FOR
SNOW SHOWERS TONIGHT WILL BE DOWNWIND OF LAKE ONTARIO AS SURFACE
AND MID-LEVEL FLOW TURNS SOUTHWESTERLY AFTER MIDNIGHT ALLOWING FOR
FOR ENHANCED LAKE EFFECT. UNDER CLOUDY SKIES OVERNIGHT LOWS REMAIN
MILD IN THE TEENS TO MID 20S.
ACTIVE WEATHER CONTINUES GOING INTO SUNDAY AS THE NORTH COUNTRY
WILL BE IMPACTED BY YET ANOTHER SHORTWAVE ROUNDING THE BASE OF THE
PERSISTENT BROAD UPPER TROUGH OVER THE EASTERN CONUS. IT`S
CURRENTLY MOVING THROUGH THE DAKOTAS THIS MORNING AND WILL TRACK
THROUGH THE OHIO RIVER VALLEY TONIGHT AND INTO THE MID-ATLANTIC
STATES SUNDAY. MEANWHILE TO OUR NORTHWEST...AN ARCTIC COLD FRONT
APPROACHES THE REGION AND THE COMBINATION OF THESE 2 FEATURES WILL
RENEW CHANCES FOR SNOW SHOWERS AND POSSIBLE SNOW SQUALLS SUNDAY
AFTERNOON AND EVENING BEFORE TAPERING OFF AFTER MIDNIGHT. ANOTHER
ROUND OF ACCUMULATING SNOW IS LIKELY ACROSS THE ENTIRE AREA WITH
AMOUNT GENERALLY 1-3" AGAIN...THOUGH COULD SEE SOME HIGHER AMOUNTS
ACROSS THE NORTHERN GREENS THROUGH SUNDAY NIGHT.
WE REMAIN UNDER THE INFLUENCE OF BROAD UPPER TROUGHINESS FOR
MONDAY AS WELL THOUGH FLOW IS GENERALLY WESTERLY AND DRIER WITH
JUST SOME CHANCE POPS ACROSS THE HIGHER TERRAIN FOR LIGHT SNOW
SHOWERS. MONDAY WILL MARK THE FIRST DAY IN AWHILE THOUGH THAT
WE`LL GO BELOW NORMAL FOR TEMPS WITH EXPECTED HIGHS ONLY IN THE
SINGLE NUMBERS TO TEENS. COLDER AIR MOVES IN FOR MONDAY NIGHT
ONWARD AS THE ARCTIC FRONT DROPS THROUGH THE REGION...MORE ON THAT
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 AM EST SATURDAY...QUIET...ALBEIT VERY COLD WEATHER ON
TAP FOR THE MIDDLE AND LATER PORTIONS OF NEXT WEEK WITH 00Z MODELS
REMAINING IN GOOD AGREEMENT SHOWING A PRONOUNCED RETURN OF ARCTIC
AIR TO THE NERN QUARTER OF THE NATION AND REMINDING US ALL THAT
IT`S STILL JANUARY. WE`RE NOT TALKING RECORD COLD BY ANY
MEANS...AND LOOKING AT RECENT TRENDS IN THE GUIDANCE THE COMING
COLD SNAP WILL LIKELY BE JUST A TAD MILDER THAN IT`S COUNTERPART
EARLIER THIS MONTH IF ANY SOLACE CAN BE TAKEN. THAT SAID IT WON`T
BE THAT PLEASANT AS DAYTIME HIGHS RANGE FROM -5F TO +5F TUE/WED
AND MODERATING ONLY VERY SLOWLY THU/FRI BY ABOUT 5 DEG EACH DAY.
LOWS GENERALLY IN THE -5F TO -15F RANGE MON NT/WED NT/THU NT WITH
COLDEST NIGHT LIKELY TUESDAY NIGHT WHEN VALUES SHOULD BOTTOM OUT
FROM 10 TO 20 BELOW. IN TERMS OF SENSIBLE WEATHER A PRETTY BORING
PATTERN HOWEVER. OUTSIDE SOME POSSIBLE WIND CHILL ISSUES MONDAY
NIGHT...NOT MUCH TO TALK ABOUT OTHER THAN THE COLD AS ARCTIC HIGH
PRESSURE MAINTAINS BROAD SYNOPTIC SCALE SUBSIDENCE AND DRY WEATHER
ACROSS THE AREA. BY FRIDAY NIGHT/SATURDAY...SOME HINTS AT A WEAK
NRN STREAM CLIPPER LOW POSSIBLY SPARKING SOME WARM ADVECTION-
DRIVEN LIGHT SNOWS/SHSN ACROSS THE AREA BUT NOTHING MORE THAN
TOKEN 30/40 POPS AT THIS POINT GIVEN WE`RE TALKING 7 DAYS OUT.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 12Z SUNDAY...MAINLY VFR CONDS EXPECTED THROUGH 18Z UNDER
LIGHT FLOW LESS THAN 10 KTS. SOME BKN/OVC VFR CIGS DURING THIS
PERIOD...BUT GENERALLY AT 060 AGL AND ABOVE. AFTER 18Z BKN/OVC
CIGS GRADUALLY LOWER WITH PERIODS OF MVFR AND/OR IFR LIGHT SNOW
POSSIBLE...ESP AT KMPV/KRUT AND KMSS. WINDS LIGHT...THOUGH
TRENDING NORTH TO NORTHEASTERLY THROUGH TIME. AREAS OF LIGHT SNOW
TAPER OFF TONIGHT LEAVING BKN/OVC VFR/MVFR CONDS WITH PATCHY BR
HERE AND THERE IN THE 3-6SM RANGE. WINDS LIGHT.
OUTLOOK 12Z SUNDAY THROUGH WEDNESDAY...
12Z SUN THROUGH 12Z MONDAY...VFR WITH SCT MVFR/IFR IN SHSN AS
ARCTIC FRONT PUSHES THROUGH THE AREA. BEST SHSN COVERAGE 18-06Z.
12Z MONDAY ONWARD...MAINLY VFR WITH HIGH PRESSURE.
&&
.EQUIPMENT...
AS OF 400 AM EST SATURDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF/TABER
SHORT TERM...LAHIFF
LONG TERM...JMG
AVIATION...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
613 AM EST SAT JAN 18 2014
.SYNOPSIS...
THE COMBINATION OF A WEAKENING UPPER DISTURBANCE AND A DEVELOPING
AREA OF LOW PRESSURE OFF THE NEW JERSEY COAST WILL BRING LIGHT
SNOW TO PORTIONS OF THE NORTH COUNTRY TODAY BEFORE TAPERING OFF
TONIGHT. MORE SNOW SHOWERS AND POSSIBLE SNOW SQUALLS ARE EXPECTED
ON SUNDAY AHEAD OF AN ARCTIC COLD FRONT...WHICH WILL MOVE THROUGH
THE REGION SUNDAY NIGHT THROUGH EARLY MONDAY. BITTERLY COLD AIR
WILL FOLLOW THE FRONT FOR ALL OF NEXT WEEK...WITH HIGHS IN THE
SINGLE DIGITS TO LOW TEENS ABOVE ZERO...AND LOWS IN THE SINGLE
DIGITS TO TEENS BELOW.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 400 AM EST SATURDAY...CHALLENGING FORECAST OVER THE NEXT 24
HOURS AS MODELS CONTINUE TO STRUGGLE TO RESOLVE SURFACE AND MID
LEVEL FEATURES AND THEIR ASSOCIATED MOISTURE AND LIFT. HAVE MADE
SEVERAL MODIFICATIONS FROM THE PREVIOUS FORECAST BASED ON CHANGES
IN GUIDANCE...GENERALLY OFFERING MUCH LESS SNOW (SIGH) ACROSS
MOST OF THE NORTH COUNTRY TODAY AND TONIGHT.
AS HAS BEEN THE CASE OVER THE LAST FEW DAYS...LATEST RUC/RAP AND
LOCAL 6KM WRF (ALSO RUC BASED) HAVE HANDLED THE FIRST 18 HOURS OF
THE FORECAST VERY WELL DUE TO INITIALIZATION INCLUDING LATEST
SATELLITE AND RADAR DATA...AND THE SAME GOES FOR TODAY. THUS HAVE
LEANED ON THEM HEAVILY FOR THE NEAR TERM FORECAST. OVERALL SYNOPTIC
SETUP FEATURES A WEAKENING MID-LEVEL SHORTWAVE OVER THE OHIO
RIVER VALLEY THIS MORNING...WHILE SURFACE LOW PRESSURE IS
BEGINNING TO DEVELOP OFF THE NJ COAST. AS BOTH OF THESE FEATURES
SHIFT NORTH/NORTHEAST THE BTV CWA IS BASICALLY SQUEEZED BETWEEN
THE 2 SYSTEMS WITH MOISTURE TO OUR SOUTHWEST AND SOUTHEAST AND
GENERALLY DRY SURFACE TO MID-LEVEL AIR IN-BETWEEN AS IS EVIDENT
BY CURRENT CLEAR SKIES ON REGIONAL IR. PRECIP ASSOCIATED WITH THESE
FEATURE DOES FILTER INTO PORTIONS OF THE FORECAST AREA TODAY
THOUGH...MAINLY ACROSS THE ST. LAWRENCE VALLEY AND SOUTHEASTERN
VERMONT DURING THE MID-MORNING HOURS...BUT AREAS IN-BETWEEN WILL
LIKELY SEE LITTLE THROUGH THE DAY UNDER PARTLY TO MOSTLY CLOUDY
SKIES. WHERE PRECIP DOES FALL...IT`LL BE IN THE FORM OF SNOW AND
WE`LL SEE SOME LIGHT ACCUMULATIONS OF GENERALLY 1-3". HIGHS TODAY
WILL REMAIN ON THE MILD SIDE OF NORMAL...WARMEST WHERE MORE
SUNSHINE WILL BE POSSIBLE IN THE CHAMPLAIN VALLEY AND NORTHERN
VERMONT...GENERALLY LOWER TO MID 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS OF 356 AM EST SATURDAY...FOR TONIGHT...AFOREMENTIONED
SHORTWAVE AND COASTAL LOW SHIFT NORTHWARD ENOUGH TO SPILL SOME
MOISTURE INTO CENTRAL PORTIONS OF THE FORECAST AREA BUT BY THAT
TIME THE DEEPEST MOISTURE IS OFFSHORE AND TO OUR NORTHWEST SO
HAVE ONLY OFFERED CHANCE POPS WITH A DUSTING TO POSSIBLY AN INCH
OF ADDITIONAL ACCUMULATION ACROSS THE ENTIRE AREA. BEST CHANCE FOR
SNOW SHOWERS TONIGHT WILL BE DOWNWIND OF LAKE ONTARIO AS SURFACE
AND MID-LEVEL FLOW TURNS SOUTHWESTERLY AFTER MIDNIGHT ALLOWING FOR
FOR ENHANCED LAKE EFFECT. UNDER CLOUDY SKIES OVERNIGHT LOWS REMAIN
MILD IN THE TEENS TO MID 20S.
ACTIVE WEATHER CONTINUES GOING INTO SUNDAY AS THE NORTH COUNTRY
WILL BE IMPACTED BY YET ANOTHER SHORTWAVE ROUNDING THE BASE OF THE
PERSISTENT BROAD UPPER TROUGH OVER THE EASTERN CONUS. IT`S
CURRENTLY MOVING THROUGH THE DAKOTAS THIS MORNING AND WILL TRACK
THROUGH THE OHIO RIVER VALLEY TONIGHT AND INTO THE MID-ATLANTIC
STATES SUNDAY. MEANWHILE TO OUR NORTHWEST...AN ARCTIC COLD FRONT
APPROACHES THE REGION AND THE COMBINATION OF THESE 2 FEATURES WILL
RENEW CHANCES FOR SNOW SHOWERS AND POSSIBLE SNOW SQUALLS SUNDAY
AFTERNOON AND EVENING BEFORE TAPERING OFF AFTER MIDNIGHT. ANOTHER
ROUND OF ACCUMULATING SNOW IS LIKELY ACROSS THE ENTIRE AREA WITH
AMOUNT GENERALLY 1-3" AGAIN...THOUGH COULD SEE SOME HIGHER AMOUNTS
ACROSS THE NORTHERN GREENS THROUGH SUNDAY NIGHT.
WE REMAIN UNDER THE INFLUENCE OF BROAD UPPER TROUGHINESS FOR
MONDAY AS WELL THOUGH FLOW IS GENERALLY WESTERLY AND DRIER WITH
JUST SOME CHANCE POPS ACROSS THE HIGHER TERRAIN FOR LIGHT SNOW
SHOWERS. MONDAY WILL MARK THE FIRST DAY IN AWHILE THOUGH THAT
WE`LL GO BELOW NORMAL FOR TEMPS WITH EXPECTED HIGHS ONLY IN THE
SINGLE NUMBERS TO TEENS. COLDER AIR MOVES IN FOR MONDAY NIGHT
ONWARD AS THE ARCTIC FRONT DROPS THROUGH THE REGION...MORE ON THAT
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 AM EST SATURDAY...QUIET...ALBEIT VERY COLD WEATHER ON
TAP FOR THE MIDDLE AND LATER PORTIONS OF NEXT WEEK WITH 00Z MODELS
REMAINING IN GOOD AGREEMENT SHOWING A PRONOUNCED RETURN OF ARCTIC
AIR TO THE NERN QUARTER OF THE NATION AND REMINDING US ALL THAT
IT`S STILL JANUARY. WE`RE NOT TALKING RECORD COLD BY ANY
MEANS...AND LOOKING AT RECENT TRENDS IN THE GUIDANCE THE COMING
COLD SNAP WILL LIKELY BE JUST A TAD MILDER THAN IT`S COUNTERPART
EARLIER THIS MONTH IF ANY SOLACE CAN BE TAKEN. THAT SAID IT WON`T
BE THAT PLEASANT AS DAYTIME HIGHS RANGE FROM -5F TO +5F TUE/WED
AND MODERATING ONLY VERY SLOWLY THU/FRI BY ABOUT 5 DEG EACH DAY.
LOWS GENERALLY IN THE -5F TO -15F RANGE MON NT/WED NT/THU NT WITH
COLDEST NIGHT LIKELY TUESDAY NIGHT WHEN VALUES SHOULD BOTTOM OUT
FROM 10 TO 20 BELOW. IN TERMS OF SENSIBLE WEATHER A PRETTY BORING
PATTERN HOWEVER. OUTSIDE SOME POSSIBLE WIND CHILL ISSUES MONDAY
NIGHT...NOT MUCH TO TALK ABOUT OTHER THAN THE COLD AS ARCTIC HIGH
PRESSURE MAINTAINS BROAD SYNOPTIC SCALE SUBSIDENCE AND DRY WEATHER
ACROSS THE AREA. BY FRIDAY NIGHT/SATURDAY...SOME HINTS AT A WEAK
NRN STREAM CLIPPER LOW POSSIBLY SPARKING SOME WARM ADVECTION-
DRIVEN LIGHT SNOWS/SHSN ACROSS THE AREA BUT NOTHING MORE THAN
TOKEN 30/40 POPS AT THIS POINT GIVEN WE`RE TALKING 7 DAYS OUT.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 12Z SUNDAY...MAINLY VFR CONDS EXPECTED THROUGH 18Z UNDER
LIGHT FLOW LESS THAN 10 KTS. SOME BKN/OVC VFR CIGS DURING THIS
PERIOD...BUT GENERALLY AT 060 AGL AND ABOVE. AFTER 18Z BKN/OVC
CIGS GRADUALLY LOWER WITH PERIODS OF MVFR AND/OR IFR LIGHT SNOW
POSSIBLE...ESP AT KMPV/KRUT AND KMSS. WINDS LIGHT...THOUGH
TRENDING NORTH TO NORTHEASTERLY THROUGH TIME. AREAS OF LIGHT SNOW
TAPER OFF TONIGHT LEAVING BKN/OVC VFR/MVFR CONDS WITH PATCHY BR
HERE AND THERE IN THE 3-6SM RANGE. WINDS LIGHT.
OUTLOOK 12Z SUNDAY THROUGH WEDNESDAY...
12Z SUN THROUGH 12Z MONDAY...VFR WITH SCT MVFR/IFR IN SHSN AS
ARCTIC FRONT PUSHES THROUGH THE AREA. BEST SHSN COVERAGE 18-06Z.
12Z MONDAY ONWARD...MAINLY VFR WITH HIGH PRESSURE.
&&
.EQUIPMENT...
AS OF 400 AM EST SATURDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...JMG
AVIATION...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
402 AM EST SAT JAN 18 2014
.SYNOPSIS...
THE COMBINATION OF A WEAKENING UPPER DISTURBANCE AND A DEVELOPING
AREA OF LOW PRESSURE OFF THE NEW JERSEY COAST WILL BRING LIGHT
SNOW TO PORTIONS OF THE NORTH COUNTRY TODAY BEFORE TAPERING OFF
TONIGHT. MORE SNOW SHOWERS AND POSSIBLE SNOW SQUALLS ARE EXPECTED
ON SUNDAY AHEAD OF AN ARCTIC COLD FRONT...WHICH WILL MOVE THROUGH
THE REGION SUNDAY NIGHT THROUGH EARLY MONDAY. BITTERLY COLD AIR
WILL FOLLOW THE FRONT FOR ALL OF NEXT WEEK...WITH HIGHS IN THE
SINGLE DIGITS TO LOW TEENS ABOVE ZERO...AND LOWS IN THE SINGLE
DIGITS TO TEENS BELOW.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 400 AM EST SATURDAY...CHALLENGING FORECAST OVER THE NEXT 24
HOURS AS MODELS CONTINUE TO STRUGGLE TO RESOLVE SURFACE AND MID
LEVEL FEATURES AND THEIR ASSOCIATED MOISTURE AND LIFT. HAVE MADE
SEVERAL MODIFICATIONS FROM THE PREVIOUS FORECAST BASED ON CHANGES
IN GUIDANCE...GENERALLY OFFERING MUCH LESS SNOW (SIGH) ACROSS
MOST OF THE NORTH COUNTRY TODAY AND TONIGHT.
AS HAS BEEN THE CASE OVER THE LAST FEW DAYS...LATEST RUC/RAP AND
LOCAL 6KM WRF (ALSO RUC BASED) HAVE HANDLED THE FIRST 18 HOURS OF
THE FORECAST VERY WELL DUE TO INITIALIZATION INCLUDING LATEST
SATELLITE AND RADAR DATA...AND THE SAME GOES FOR TODAY. THUS HAVE
LEANED ON THEM HEAVILY FOR THE NEAR TERM FORECAST. OVERALL SYNOPTIC
SETUP FEATURES A WEAKENING MID-LEVEL SHORTWAVE OVER THE OHIO
RIVER VALLEY THIS MORNING...WHILE SURFACE LOW PRESSURE IS
BEGINNING TO DEVELOP OFF THE NJ COAST. AS BOTH OF THESE FEATURES
SHIFT NORTH/NORTHEAST THE BTV CWA IS BASICALLY SQUEEZED BETWEEN
THE 2 SYSTEMS WITH MOISTURE TO OUR SOUTHWEST AND SOUTHEAST AND
GENERALLY DRY SURFACE TO MID-LEVEL AIR IN-BETWEEN AS IS EVIDENT
BY CURRENT CLEAR SKIES ON REGIONAL IR. PRECIP ASSOCIATED WITH THESE
FEATURE DOES FILTER INTO PORTIONS OF THE FORECAST AREA TODAY
THOUGH...MAINLY ACROSS THE ST. LAWRENCE VALLEY AND SOUTHEASTERN
VERMONT DURING THE MID-MORNING HOURS...BUT AREAS IN-BETWEEN WILL
LIKELY SEE LITTLE THROUGH THE DAY UNDER PARTLY TO MOSTLY CLOUDY
SKIES. WHERE PRECIP DOES FALL...IT`LL BE IN THE FORM OF SNOW AND
WE`LL SEE SOME LIGHT ACCUMULATIONS OF GENERALLY 1-3". HIGHS TODAY
WILL REMAIN ON THE MILD SIDE OF NORMAL...WARMEST WHERE MORE
SUNSHINE WILL BE POSSIBLE IN THE CHAMPLAIN VALLEY AND NORTHERN
VERMONT...GENERALLY LOWER TO MID 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS OF 356 AM EST SATURDAY...FOR TONIGHT...AFOREMENTIONED
SHORTWAVE AND COASTAL LOW SHIFT NORTHWARD ENOUGH TO SPILL SOME
MOISTURE INTO CENTRAL PORTIONS OF THE FORECAST AREA BUT BY THAT
TIME THE DEEPEST MOISTURE IS OFFSHORE AND TO OUR NORTHWEST SO
HAVE ONLY OFFERED CHANCE POPS WITH A DUSTING TO POSSIBLY AN INCH
OF ADDITIONAL ACCUMULATION ACROSS THE ENTIRE AREA. BEST CHANCE FOR
SNOW SHOWERS TONIGHT WILL BE DOWNWIND OF LAKE ONTARIO AS SURFACE
AND MID-LEVEL FLOW TURNS SOUTHWESTERLY AFTER MIDNIGHT ALLOWING FOR
FOR ENHANCED LAKE EFFECT. UNDER CLOUDY SKIES OVERNIGHT LOWS REMAIN
MILD IN THE TEENS TO MID 20S.
ACTIVE WEATHER CONTINUES GOING INTO SUNDAY AS THE NORTH COUNTRY
WILL BE IMPACTED BY YET ANOTHER SHORTWAVE ROUNDING THE BASE OF THE
PERSISTENT BROAD UPPER TROUGH OVER THE EASTERN CONUS. IT`S
CURRENTLY MOVING THROUGH THE DAKOTAS THIS MORNING AND WILL TRACK
THROUGH THE OHIO RIVER VALLEY TONIGHT AND INTO THE MID-ATLANTIC
STATES SUNDAY. MEANWHILE TO OUR NORTHWEST...AN ARCTIC COLD FRONT
APPROACHES THE REGION AND THE COMBINATION OF THESE 2 FEATURES WILL
RENEW CHANCES FOR SNOW SHOWERS AND POSSIBLE SNOW SQUALLS SUNDAY
AFTERNOON AND EVENING BEFORE TAPERING OFF AFTER MIDNIGHT. ANOTHER
ROUND OF ACCUMULATING SNOW IS LIKELY ACROSS THE ENTIRE AREA WITH
AMOUNT GENERALLY 1-3" AGAIN...THOUGH COULD SEE SOME HIGHER AMOUNTS
ACROSS THE NORTHERN GREENS THROUGH SUNDAY NIGHT.
WE REMAIN UNDER THE INFLUENCE OF BROAD UPPER TROUGHINESS FOR
MONDAY AS WELL THOUGH FLOW IS GENERALLY WESTERLY AND DRIER WITH
JUST SOME CHANCE POPS ACROSS THE HIGHER TERRAIN FOR LIGHT SNOW
SHOWERS. MONDAY WILL MARK THE FIRST DAY IN AWHILE THOUGH THAT
WE`LL GO BELOW NORMAL FOR TEMPS WITH EXPECTED HIGHS ONLY IN THE
SINGLE NUMBERS TO TEENS. COLDER AIR MOVES IN FOR MONDAY NIGHT
ONWARD AS THE ARCTIC FRONT DROPS THROUGH THE REGION...MORE ON THAT
BELOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 AM EST SATURDAY...QUIET...ALBEIT VERY COLD WEATHER ON
TAP FOR THE MIDDLE AND LATER PORTIONS OF NEXT WEEK WITH 00Z MODELS
REMAINING IN GOOD AGREEMENT SHOWING A PRONOUNCED RETURN OF ARCTIC
AIR TO THE NERN QUARTER OF THE NATION AND REMINDING US ALL THAT
IT`S STILL JANUARY. WE`RE NOT TALKING RECORD COLD BY ANY
MEANS...AND LOOKING AT RECENT TRENDS IN THE GUIDANCE THE COMING
COLD SNAP WILL LIKELY BE JUST A TAD MILDER THAN IT`S COUNTERPART
EARLIER THIS MONTH IF ANY SOLACE CAN BE TAKEN. THAT SAID IT WON`T
BE THAT PLEASANT AS DAYTIME HIGHS RANGE FROM -5F TO +5F TUE/WED
AND MODERATING ONLY VERY SLOWLY THU/FRI BY ABOUT 5 DEG EACH DAY.
LOWS GENERALLY IN THE -5F TO -15F RANGE MON NT/WED NT/THU NT WITH
COLDEST NIGHT LIKELY TUESDAY NIGHT WHEN VALUES SHOULD BOTTOM OUT
FROM 10 TO 20 BELOW. IN TERMS OF SENSIBLE WEATHER A PRETTY BORING
PATTERN HOWEVER. OUTSIDE SOME POSSIBLE WIND CHILL ISSUES MONDAY
NIGHT...NOT MUCH TO TALK ABOUT OTHER THAN THE COLD AS ARCTIC HIGH
PRESSURE MAINTAINS BROAD SYNOPTIC SCALE SUBSIDENCE AND DRY WEATHER
ACROSS THE AREA. BY FRIDAY NIGHT/SATURDAY...SOME HINTS AT A WEAK
NRN STREAM CLIPPER LOW POSSIBLY SPARKING SOME WARM ADVECTION-
DRIVEN LIGHT SNOWS/SHSN ACROSS THE AREA BUT NOTHING MORE THAN
TOKEN 30/40 POPS AT THIS POINT GIVEN WE`RE TALKING 7 DAYS OUT.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 06Z SUNDAY...MAINLY VFR CONDS EXPECTED THROUGH 18Z UNDER
LIGHT FLOW LESS THAN 10 KTS. SOME BKN/OVC VFR CIGS DURING THIS
PERIOD...BUT GENERALLY AT 060 AGL AND ABOVE. AFTER 18Z BKN/OVC
CIGS GRADUALLY LOWER WITH PERIODS OF MVFR AND/OR IFR LIGHT SNOW
POSSIBLE...ESP AT KMPV/KRUT AND KMSS. WINDS LIGHT...THOUGH
TRENDING NORTH TO NORTHEASTERLY THROUGH TIME.
OUTLOOK 06Z SUNDAY THROUGH WEDNESDAY...SFC LOW PRES WL PRODUCE
OCCASIONAL SNOW SHOWERS ON SAT NIGHT INTO SUNDAY WITH PERIODS OF
IFR/LIFR CONDITIONS LIKELY. AN ARCTIC FRNT WL PRODUCE ADDITIONAL
SCATTERED SNOW SHOWERS WITH MAYBE A SNOW SQUALL SUNDAY EVENING
INTO MONDAY WITH MORE MVFR/IFR CONDITIONS POSSIBLE. GENERAL CLRING
WITH VFR CONDITIONS WL RETURN FOR MONDAY INTO TUESDAY ASSOCIATED
WITH ARCTIC HIGH PRES.
&&
.EQUIPMENT...
AS OF 400 AM EST SATURDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...JMG
AVIATION...BANACOS/JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
949 PM CST SUN JAN 19 2014
.UPDATE...
ISSUED AT 949 PM CST SUN JAN 19 2014
LOW PRESSURE TROUGH SITUATED FROM NEAR REGINA SASKATCHEWAN
SOUTHEAST THROUGH MINOT AND JAMESTOWN. UPPER LEVEL WAVE ON WV
IMAGERY IS CURRENTLY DROPPING SOUTHEAST THROUGH SOUTHERN
SASKATCHEWAN. AREA OF LIGHT SNOW CURRENTLY INDICATED OVER RENVILLE
AND WESTERN BOTTINEAU COUNTY WITH LIGHTER REFLECTIVITIES NORTHWARD
INTO FAR SOUTHEAST SASKATCHEWAN AND SOUTHWEST MANITOBA. LATEST
MESOSCALE MODELS TRACK THIS AREA OF SNOW SOUTHEAST WITH MORE LIGHT
SNOW FILLING IN FROM THE NORTH AFTER 06 UTC...ASSOCIATED WITH THE
AFOREMENTIONED SHORTWAVE. CURRENT FORECAST TEMPERATURES LOOK
REASONABLE. MAIN ADJUSTMENTS WITH THE EVENING UPDATE WERE UPDATES
TO HOURLY POPS THROUGH THE REMAINDER OF THE EVENING BASED ON CURRENT
RADAR...AND FUTURE POPS BASED ON 02Z RAP AND 00Z NAM.
UPDATE ISSUED AT 635 PM CST SUN JAN 19 2014
LOW STRATUS REMAINS OVER NORTHEAST NORTH DAKOTA...JUST EAST OF THE
FORECAST AREA...WITH INCREASING MID AND HIGH LEVEL CLOUDINESS FROM
THE WEST. MAIN UPDATE THIS EVENING WAS TO CUT BACK ON POPS OVER
THE EASTERN CWA THIS EVENING. COULD BE A FLURRY OR TWO IN THE
STRATUS AND THAT SHOULD SPREAD WEST LATER TONIGHT. SURFACE LOW
WILL CONTINUE TO DROP SOUTHEAST THROUGH SOUTHERN SASKATCHEWAN THIS
EVENING. 22Z HRRR AND 23Z RAP MESOSCALE MODELS ARE INDICATING
INCREASING POPS FROM NORTH TO SOUTH AFTER 06Z. ALSO ADJUSTED SKY
COVER BASED ON LATEST SATELLITE IMAGERY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE MAIN FOCUS OF TODAY`S FORECAST IS WIND TOMORROW. 12 UTC
NAM/GFS SOUNDINGS SUGGEST THERE WILL BE AT LEAST A COUPLE HOUR
PERIOD OF FAVORABLE MIXING CONDITIONS WITH WINDS A LITTLE OVER 40
KNOTS AT THE TOP OF THE MIXED LAYER. THERE IS CONSIDERABLE
UNCERTAINTY AS THE GFS IS MUCH FASTER TO SQUASH MIXING THAN THE
NAM...SUGGESTING THAT GOOD DOWNWARD MOMENTUM TRANSFER MAY NOT EVEN
MATERIALIZE. THE FORECAST REMAINS BELOW WIND ADVISORY
CRITERIA...BUT THAT WILL NEED TO BE WATCHED CLOSELY.
RIGHT NOW...THE BACKDOOR COLD FRONT SLOWLY MOVING TOWARD THE
TURTLE MOUNTAINS SHOULD SPEED UP ONCE THE WEAK LOW PRESSURE CENTER
OVER SOUTHEASTERN SASKATCHEWAN SLIDES ACROSS THE DEVILS LAKE BASIN
THIS EVENING. LIGHT SNOW WILL ACCOMPANY THE FRONTAL ZONE...AND
THERE IS GREAT MODEL AGREEMENT THAT UP TO 2 INCHES WILL FALL ALONG
THE U.S. HIGHWAY 83 CORRIDOR AND EAST.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE NORTHERN PLAINS REMAINS UNDER A QUASI-ACTIVE NORTHWEST FLOW
ALOFT DURING ALL OF THE COMING WORK WEEK AND THROUGH NEXT WEEKEND.
WILL SEE SEVERAL EMBEDDED S/WV`S TRAVERSING NORTH DAKOTA WITHIN THE
FLOW ALOFT BRINGING CHANCES FOR PRECIPITATION ALONG WITH POSSIBLE
NON-DIURNAL TEMPERATURE SWINGS.
THE LONG TERM BEGINS MONDAY NIGHT WITH A STRONG 1040MB SURFACE HIGH
PROPAGATING SOUTH-SOUTHEAST ACROSS THE DAKOTAS TOWARDS THE UPPER
MISSISSIPPI RIVER VALLEY. TUESDAY MORNING LOWS WILL NEAR 20 BELOW
OVER MY EAST...BUT SHOULD REMAIN CLOSER TO 15 BELOW WITH CLOUDS
EXPECTED TO INCREASE THERE AFTER MIDNIGHT. WARMER WEST...ZERO TO THE
SINGLE DIGITS ABOVE...THANKS TO RETURN FLOW/WEAK WAA.
FIRST IN A SERIES OF EMBEDDED IMPULSES WILL MOVE THROUGH THE REGION
TUESDAY...FOLLOWED BY A BROADER S/WV TROUGH WEDNESDAY. EACH OF THESE
FEATURES WILL BRING A CHANCE FOR SNOW...THE FIRST ACROSS THE EASTERN
THIRD OF THE STATE (GRAZING MY FAR EASTERN COUNTIES) AND THE SECOND
MORE WIDESPREAD WITH LIGHT SNOW ACROSS WEST AND CENTRAL ND. LIMITED
MOISTURE WITH EACH FEATURE SO NOT EXPECTING MUCH IN THE WAY OF
ACCUMULATING SNOWFALL. THE TROUGH ON WEDNESDAY WILL BRING STRONG CAA
ACROSS THE NORTHERN PLAINS...WITH FALLING TEMPERATURES LIKELY
WEDNESDAY THROUGH WEDNESDAY NIGHT. WITH WIND SPEEDS NEAR
10KTS...WILL NEED TO MONITOR FOR POSSIBLE WIND CHILL HEADLINES
DURING THE DAY WEDNESDAY AND FOR WEDNESDAY NIGHT/THURSDAY MORNING
WITH SUBZERO TEMPERATURES.
MODEL UNCERTAINTY INCREASES FROM THE END OF THE WORK WEEK THROUGH
NEXT WEEKEND. BOTH THE 12Z GFS AND ECMWF DIFFER ON THE TIMING AND
PLACEMENT OF POSSIBLE WAVES MOVING THROUGH IN THE FLOW ALOFT...AND
ARE ALSO FLUCTUATING MODEL RUN TO RUN. OVERALL...THE ACTIVE PATTERN
REMAINS IN PLACE...WITH THE THERMAL BOUNDARY REMAINING
QUASI-STATIONARY WITH COLDER TEMPERATURES NORTHEAST AND WARMER
SOUTHWEST. THE VERY COLD AIR PREVIOUSLY ADVERTISED FOR NEXT WEEKEND
IS NOW CONSISTENTLY (OVER THE LAST 3-4 GFS/ECMWF RUNS) BEING
DEPICTED TO REMAIN WELL TO OUR EAST OVER THE GREAT LAKES...ALTHOUGH
WE MAY STILL EXPERIENCE THE WESTERN EDGE OF THIS ARCTIC AIRMASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 949 PM CST SUN JAN 19 2014
MVFR TO IFR STRATUS BEHIND A COLD FRONT WILL MOVE SLOWLY
SOUTHWARD OVER ALL TAF SITES TONIGHT. SNOW WILL LAG THE CLOUDS BY
A FEW HOURS AT KJMS/KMOT/KBIS. SOME BLOWING SNOW IS POSSIBLE...BUT
IS HIGHLY DEPENDENT UPON AMOUNT AND TIMING OF SNOWFALL.
THEREAFTER...LOW STRATUS WILL LIKELY REMAIN THROUGH THE MORNING
THEN DECREASE FROM NORTH TO SOUTH DURING THE AFTERNOON MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
635 PM CST SUN JAN 19 2014
.UPDATE...
ISSUED AT 635 PM CST SUN JAN 19 2014
LOW STRATUS REMAINS OVER NORTHEAST NORTH DAKOTA...JUST EAST OF THE
FORECAST AREA...WITH INCREASING MID AND HIGH LEVEL CLOUDINESS FROM
THE WEST. MAIN UPDATE THIS EVENING WAS TO CUT BACK ON POPS OVER
THE EASTERN CWA THIS EVENING. COULD BE A FLURRY OR TWO IN THE
STRATUS AND THAT SHOULD SPREAD WEST LATER TONIGHT. SURFACE LOW
WILL CONTINUE TO DROP SOUTHEAST THROUGH SOUTHERN SASKATCHEWAN THIS
EVENING. 22Z HRRR AND 23Z RAP MESOSCALE MODELS ARE INDICATING
INCREASING POPS FROM NORTH TO SOUTH AFTER 06Z. ALSO ADJUSTED SKY
COVER BASED ON LATEST SATELLITE IMAGERY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE MAIN FOCUS OF TODAY`S FORECAST IS WIND TOMORROW. 12 UTC
NAM/GFS SOUNDINGS SUGGEST THERE WILL BE AT LEAST A COUPLE HOUR
PERIOD OF FAVORABLE MIXING CONDITIONS WITH WINDS A LITTLE OVER 40
KNOTS AT THE TOP OF THE MIXED LAYER. THERE IS CONSIDERABLE
UNCERTAINTY AS THE GFS IS MUCH FASTER TO SQUASH MIXING THAN THE
NAM...SUGGESTING THAT GOOD DOWNWARD MOMENTUM TRANSFER MAY NOT EVEN
MATERIALIZE. THE FORECAST REMAINS BELOW WIND ADVISORY
CRITERIA...BUT THAT WILL NEED TO BE WATCHED CLOSELY.
RIGHT NOW...THE BACKDOOR COLD FRONT SLOWLY MOVING TOWARD THE
TURTLE MOUNTAINS SHOULD SPEED UP ONCE THE WEAK LOW PRESSURE CENTER
OVER SOUTHEASTERN SASKATCHEWAN SLIDES ACROSS THE DEVILS LAKE BASIN
THIS EVENING. LIGHT SNOW WILL ACCOMPANY THE FRONTAL ZONE...AND
THERE IS GREAT MODEL AGREEMENT THAT UP TO 2 INCHES WILL FALL ALONG
THE U.S. HIGHWAY 83 CORRIDOR AND EAST.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE NORTHERN PLAINS REMAINS UNDER A QUASI-ACTIVE NORTHWEST FLOW
ALOFT DURING ALL OF THE COMING WORK WEEK AND THROUGH NEXT WEEKEND.
WILL SEE SEVERAL EMBEDDED S/WV`S TRAVERSING NORTH DAKOTA WITHIN THE
FLOW ALOFT BRINGING CHANCES FOR PRECIPITATION ALONG WITH POSSIBLE
NON-DIURNAL TEMPERATURE SWINGS.
THE LONG TERM BEGINS MONDAY NIGHT WITH A STRONG 1040MB SURFACE HIGH
PROPAGATING SOUTH-SOUTHEAST ACROSS THE DAKOTAS TOWARDS THE UPPER
MISSISSIPPI RIVER VALLEY. TUESDAY MORNING LOWS WILL NEAR 20 BELOW
OVER MY EAST...BUT SHOULD REMAIN CLOSER TO 15 BELOW WITH CLOUDS
EXPECTED TO INCREASE THERE AFTER MIDNIGHT. WARMER WEST...ZERO TO THE
SINGLE DIGITS ABOVE...THANKS TO RETURN FLOW/WEAK WAA.
FIRST IN A SERIES OF EMBEDDED IMPULSES WILL MOVE THROUGH THE REGION
TUESDAY...FOLLOWED BY A BROADER S/WV TROUGH WEDNESDAY. EACH OF THESE
FEATURES WILL BRING A CHANCE FOR SNOW...THE FIRST ACROSS THE EASTERN
THIRD OF THE STATE (GRAZING MY FAR EASTERN COUNTIES) AND THE SECOND
MORE WIDESPREAD WITH LIGHT SNOW ACROSS WEST AND CENTRAL ND. LIMITED
MOISTURE WITH EACH FEATURE SO NOT EXPECTING MUCH IN THE WAY OF
ACCUMULATING SNOWFALL. THE TROUGH ON WEDNESDAY WILL BRING STRONG CAA
ACROSS THE NORTHERN PLAINS...WITH FALLING TEMPERATURES LIKELY
WEDNESDAY THROUGH WEDNESDAY NIGHT. WITH WIND SPEEDS NEAR
10KTS...WILL NEED TO MONITOR FOR POSSIBLE WIND CHILL HEADLINES
DURING THE DAY WEDNESDAY AND FOR WEDNESDAY NIGHT/THURSDAY MORNING
WITH SUBZERO TEMPERATURES.
MODEL UNCERTAINTY INCREASES FROM THE END OF THE WORK WEEK THROUGH
NEXT WEEKEND. BOTH THE 12Z GFS AND ECMWF DIFFER ON THE TIMING AND
PLACEMENT OF POSSIBLE WAVES MOVING THROUGH IN THE FLOW ALOFT...AND
ARE ALSO FLUCTUATING MODEL RUN TO RUN. OVERALL...THE ACTIVE PATTERN
REMAINS IN PLACE...WITH THE THERMAL BOUNDARY REMAINING
QUASI-STATIONARY WITH COLDER TEMPERATURES NORTHEAST AND WARMER
SOUTHWEST. THE VERY COLD AIR PREVIOUSLY ADVERTISED FOR NEXT WEEKEND
IS NOW CONSISTENTLY (OVER THE LAST 3-4 GFS/ECMWF RUNS) BEING
DEPICTED TO REMAIN WELL TO OUR EAST OVER THE GREAT LAKES...ALTHOUGH
WE MAY STILL EXPERIENCE THE WESTERN EDGE OF THIS ARCTIC AIRMASS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 635 PM CST SUN JAN 19 2014
MVFR TO IFR STRATUS BEHIND A COLD FRONT WILL MOVE SLOWLY
SOUTHWARD OVER ALL TAF SITES TONIGHT. SNOW WILL LAG THE CLOUDS BY
A FEW HOURS AT KJMS/KMOT/KBIS. SOME BLOWING SNOW IS POSSIBLE...BUT
IS HIGHLY DEPENDENT UPON AMOUNT AND TIMING OF SNOWFALL.
THEREAFTER...LOW STRATUS WILL LIKELY REMAIN THROUGH THE MORNING
THEN DECREASE FROM NORTH TO SOUTH DURING THE AFTERNOON MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
103 AM CST SAT JAN 18 2014
.UPDATE...
ISSUED AT 103 AM CST SAT JAN 18 2014
CENTER OF THE SURFACE LOW CLIPPER WAS BETWEEN DEVILS LAKE AND GRAND
FORKS AND MOVING SOUTHEAST.
SUSTAINED WINDS OF AT LEAST 30 MPH WITH GUSTS TO AROUND 40 MPH WERE
COMMON ACROSS MOST OF CENTRAL AND PARTS OF WESTERN NORTH DAKOTA.
HIGHEST WINDS AND GUSTS WERE REPORTED IN THE ROLETTE COUNTY AREA.
THUS FORECAST WINDS ARE IN VERY GOOD SHAPE FOR THE OVERNIGHT HOURS.
LATEST RADAR LOOPS FROM CANADIAN AND NORTH DAKOTA RADARS INDICATING
SNOW SHOWERS EXTENDING FARTHER WEST THAN PREVIOUSLY THOUGHT. ALSO
MORE CONFIDENT THAT SNOW WILL OCCUR IN THE TURTLE MOUNTAINS TO JAMES
RIVER VALLEY...SO RAISED CHANCES TO "LIKELY" THERE. LOOKING LIKE
FARTHER WEST THE RUC13 AND NAM INDICATING SCATTERED SNOW SHOWERS
ACROSS THE REST OF CENTRAL NORTH DAKOTA OVERNIGHT. RADAR LOOPS
SHOWING SNOW SHOWERS AS FAR WEST AS STANLEY...WITH MORE MOVING SOUTH
OUT OF CANADA.
HEADLINES FOR WIND ADVISORY AND WINTER WEATHER ADVISORY STILL OK.
WAS CONCERNED ABOUT THE TURTLE MOUNTAIN/PIERCE COUNTY AREA...BUT
LOOKS LIKE SNOW SHOWERS SHOULD NOT LAST THERE VERY LONG.
UPDATE ISSUED AT 949 PM CST FRI JAN 17 2014
THE MINOT AIR FORCE BASE REPORTED A WIND GUST OF 47 MPH ABOUT AN
HOUR AGO. THE ROLLA AIRPORT REPORTED A GUST OF 46 MPH WITHIN THE
LAST HOUR AS WELL. WINDS MEETING WIND ADVISORY CRITERIA WILL CONTINUE
TO PUSH SOUTH COINCIDENT WITH THE MOST UNSTABLE BOUNDARY LAYER
LAPSE RATES. THESE HIGHER WINDS ARE MOVING SOUTH ACROSS THE STATE ON
SCHEDULE SO WILL NOT ADJUST THE HEADLINES FOR THIS UPDATE. ONLY
ADJUSTED HOURLY SENSIBLE WEATHER BASED ON CURRENT OBS/TRENDS. THE
FRESHENED UP PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 707 PM CST FRI JAN 17 2014
IN RESPONSE TO AN APPROACHING CLIPPER...BOTH THE GFS AND ECMWF
PROG 50 KNOTS OF WIND DEVELOPING AT 850MB AROUND 06Z TONIGHT. LOW-
LEVEL (1000MB-850MB) LAPSE RATES GO FROM AROUND 6 C/KM AT 06Z...TO
ALMOST 7 C/KM AT 12Z SATURDAY OVER WESTERN NORTH DAKOTA. EVEN
THOUGH ALL 50 KNOTS OF MOMENTUM ARE NOT EXPECTED TO MIX TO THE
SURFACE...AT LEAST 40 KNOTS SHOULD BE REALIZED AT THE SURFACE. AS
A RESULT...INCREASED THE FIRST PERIOD WIND FORECAST WEST AND EXPANDED
THE WIND ADVISORY WEST TO ENCAPSULATE THE REMAINING NORTH DAKOTA
COUNTIES. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 308 PM CST FRI JAN 17 2014
12 UTC MODEL/ENSEMBLE GUIDANCE SUPPORTS WESTWARD EXPANSION OF THE
WIND ADVISORY TO INCLUDE A FEW MORE COUNTIES IN THE
SOUTHWEST/SOUTH CENTRAL. BUFKIT SOUNDINGS FROM THE 09/15 UTC SREF
MEAN/NAM/GFS ALL INDICATE SUFFICIENT DOWNWARD MOMENTUM FLUX TO
INCREASE WIND FORECASTS AND EXPAND THE ADVISORY.
FURTHER EAST IN THE JAMES RIVER VALLEY...THE WIND ADVISORY WAS
REPLACED BY A WINTER WEATHER ADVISORY. LIGHT SNOW AHEAD OF
STRONGER WINDS THIS EVENING LOOKS TO BE SUFFICIENT FOR SUBSTANTIAL
REDUCTIONS IN VISIBILITY DUE TO BLOWING SNOW. MOREOVER...IF SNOW
IS SLOWER TO EXIT OR WIND IS EARLY...NEAR BLIZZARD CONDITIONS WILL
RESULT. THE AFOREMENTIONED UNCERTAINTY WILL EXIST UNTIL THE EVENT
IS UNDERWAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 PM CST FRI JAN 17 2014
THE NORTHERN PLAINS REMAINS IN NORTHWEST FLOW ALOFT THROUGH THE LONG
TERM PERIOD. SEVERAL CLIPPER SYSTEMS ARE FORECAST BY 12Z MODELS
(GFS/EC/GEM) TO IMPACT THE REGION LATE THIS WEEKEND AND WELL THROUGH
NEXT WEEK.
THE FIRST IN A SERIES OF FAST MOVING CLIPPERS WILL MOVE ACROSS THE
NORTHERN PLAINS/UPPER MIDWEST DURING THE DAY SUNDAY...FOLLOWED
QUICKLY BY TWO MORE WAVES SUNDAY NIGHT AND ANOTHER ON MONDAY. BEFORE
SUNDAYS WAVE...WAA WITH 850MB TEMPS +4 TO +8C AND A 15-20KT WESTERLY
MIXING WIND SHOULD MAINTAIN RELATIVELY MILD OVERNIGHT LOWS WITH
TEMPERATURES SUNDAY MORNING IN THE MID 20S TO MID 30S. WILL NOT SEE
MUCH TEMPERATURE RECOVERY SUNDAY DAYTIME WITH ALL MODELS BRINGING A
COLD FRONT NORTHEAST TO SOUTHWEST ACROSS NORTH DAKOTA. CHANCES FOR
SNOW WILL ACCOMPANY THE FRONT/CAA NORTHEAST SUNDAY
MORNING...SPREADING SOUTH AND WEST SUNDAY AFTERNOON INTO SUNDAY
NIGHT AS CAA CONTINUES TO SPREAD SOUTHWEST. THE NEXT TWO EMBEDDED
WAVES WILL DRIVE THE FRONTAL ZONE FARTHER SOUTHWEST SUNDAY NIGHT
INTO MONDAY. EXPECT ANY SNOW TO END BY MONDAY EVENING AS THE THIRD
MID LEVEL IMPULSE/CLIPPER MOVES SOUTHEAST OUT OF THE REGION.
TEMPERATURES WILL BE NOTICEABLY COLDER ON MONDAY WITH HIGHS AROUND
ZERO ACROSS THE TURTLE MOUNTAINS TO THE LOW/MID 20S SOUTHWEST. LOWS
TUESDAY MORNING WILL RANGE FROM 10 BELOW EAST TO 10 ABOVE WEST AS A
COLD 1040MB AREA OF HIGH PRESSURE BUILDS SOUTH ACROSS THE EASTERN
DAKOTAS.
STRONGEST WINDS SUNDAY THROUGH MONDAY DAYTIME WILL BE ACROSS THE
WESTERN HALF OF THE DAKOTAS...ALONG TO WEST OF THE TRACK OF THE
SURFACE LOW PRESSURE SYSTEMS. AT THIS TIME WINDS ARE EXPECTED TO
REMAIN SUB-ADVISORY AS WE NEVER REALLY DEVELOP THE STRONG PRESSURE
RISES AS WE SAW ON THURSDAY MORNING OR WHAT WE WILL SEE LATE TONIGHT
CENTRAL AND EAST. STILL...WILL HAVE TO MONITOR THE HIGHER TERRAIN OF
THE FAR SOUTHWEST IN CASE GRADIENT FORCING INCREASES WITH FUTURE
MODEL RUNS.
YET ANOTHER WEAK CLIPPER/FRONTAL PASSAGE ARRIVES MID-WEEK...FOLLOWED
BY THE POTENTIAL FOR ANOTHER ARCTIC COLD SNAP THE FOLLOWING WEEKEND.
WILL NOT GET INTO DETAILS REGARDING ANYTHING PAST TUESDAY UNTIL
MODELS COME INTO BETTER ALIGNMENT AND WE PASS THE THREATS OR
POTENTIAL THREATS OVER THE NEXT FEW DAYS THROUGH MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 103 AM CST SAT JAN 18 2014
MVFR CIGS WILL OVERSPREAD THE STATE FROM NORTH TO SOUTH THROUGH
THE OVERNIGHT HOURS. THERE IS A CHANCE OF LIGHT SNOW AT
KMOT/KJMS/KBIS WITH BLOWING SNOW POSSIBLE AS WELL. NORTHWESTERLY
WINDS WILL GUST TO 40 KNOTS. WINDS TO DECREASE FROM NORTHWEST TO
SOUTHEAST BEGINNING AFTER 13Z. LIFR CONDITIONS IN BLOWING SNOW IS
EXPECTED TO DEVELOP OVER KJMS BETWEEN 09Z-13Z...WITH ONLY MVFR
CIGS FROM KISN-KMOT-KDIK-KBIS GENERALLY DURING THE SAME PERIOD.
VFR CONDITIONS ARE EXPECTED AREAWIDE BY SATURDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 AM CST THIS MORNING FOR NDZ001>005-009>013-
017>019-021.
WIND ADVISORY UNTIL 7 AM MST THIS MORNING FOR NDZ031>033-040-043.
WIND ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NDZ020-022-
023-034>036-041-042-044>047-050.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NDZ025-037-048-
051.
&&
$$
UPDATE...JV
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION...UPDATED
NWS MEDFORD OR
955 PM PST FRI JAN 17 2014
AVIATION SECTION UPDATED FOR 06Z TAF ISSUANCE
.UPDATE...
AN UPDATE HAS BEEN MADE THIS EVENING TO ADJUST TEMPERATURES,
MOSTLY DOWN, A BIT. ADJUSTMENTS WERE ALSO MADE TO ADDRESS SKY
COVER AND FOG RELATED TO A SOUTHERLY STRATUS SURGE OVER THE
COASTAL WATERS AND FROM THE WEST SLOPES OF THE COAST RANGE
WESTWARD. SKY AND FOG COVERAGE WAS ALSO FINE TUNED, PRIMARILY TO
ACCOUNT FOR A DENSE FREEZING FOG ADVISORY IN THE VALLEYS OF
JACKSON AND JOSEPHINE COUNTIES.
&&
.DISCUSSION...
A STRATUS SURGE HAS REACHED THE COAST FROM THE SOUTHWEST THIS
EVENING. THE ONLY MODEL THAT DID A GOOD JOB PICKING UP ON THIS
FEATURE IS THE HRRR-3KM, SO HAVE FOLLOWED IT WITH UPDATES THROUGH
THE MORNING.
ON SATURDAY WE DO EXPECT FOG WILL LIKELY DISSIPATE COMPLETELY
DURING THE AFTERNOON ACROSS ALL WEST SIDE VALLEYS DUE TO SOME
COOLING ABOVE THE BOUNDARY LAYER AND LESS SUBSIDENCE OVER THE
AREA. HOWEVER, THIS IS NOT A GUARANTEE, AS CHANGES ARE SUBTLE.
ALSO, IN SIMILAR PAST CASES, WITH THE FLOW ALOFT TURNING FROM
SOUTHEAST TO SOUTH TO SOUTHWEST, ROSEBURG OFTEN HAS A TOUGHER
TIME SHAKING THE STRATUS. HOWEVER, TRENDS IN TEMPERATURES AND THE
INVERSION TODAY SUGGEST IT SHOULD CLEAR FOR AT LEAST A FEW HOURS
IN THE AFTERNOON AND EVENING.
PLEASE SEE THE CLIMATE SECTION FOR LONG TERM INFORMATION.
&&
.AVIATION...BASED ON THE 18/06Z TAF CYCLE...
A STRATUS SURGE HAS REACHED PORTIONS OF THE COAST THIS EVENING, WITH
NORTH BEND MOSTLY UNDER IT AND BROOKINGS ABOVE IT. THE HRRR 3KM
MODEL, WHICH HAS BEEN DOING QUITE WELL ALONG THE COAST THIS EVENING,
INDICATES THIS IFR TO LIFR FOG AND STRATUS WILL MOVE MORE
DEFINITIVELY ONTO THE COAST BETWEEN 08Z AND 09Z. THEREFORE, EXPECT
THAT NORTH BEND WILL LIKELY HAVE IFR STRATUS AND FOG THIS EVENING
THROUGH THE MORNING, AS WILL OTHER AREAS WEST OF AND ON THE WEST
SLOPES OF THE COAST RANGE. ELSEWHERE, FOG AND LOW CLOUDS OF THE LIFR
VARIETY ARE EXPECTED AGAIN IN THE SAME WEST SIDE VALLEYS AS THE LAST
FEW DAYS. ON THE EAST SIDE A SLIGHT RISE IN TEMPERATURES TONIGHT
MEANS FOG SHOULD BE A LITTLE LESS IN COVERAGE AND DURATION. A WEAKER
INVERSION DUE TO COOLING AT THE TOP OF THE BOUNDARY LAYER ON
SATURDAY SHOULD BE ENOUGH FOR ALL LOCATIONS TO CLEAR OUT. SIMILAR
PAST SCENARIOS INDICATE THAT ROSEBURG MAY BE THE LAST TO CLEAR
SATURDAY AFTERNOON. BTL
&&
.MARINE...
SOUTH WINDS WILL BECOME NORTHERLY DURING THE DAYLIGHT HOURS OF
SATURDAY. LOW CLOUDS AND SOME FOG OVER THE WATERS TONIGHT SHOULD
LIFT TOWARD MORNING AND THROUGH THE DAY ON SATURDAY DUE TO COOLING
AT THE TOP OF THE BOUNDARY LAYER. WEST SWELL WILL BE ON THE INCREASE
THIS WEEKEND, LIKELY REACHING 10 FEET SATURDAY NIGHT INTO SUNDAY.
THIS WEST SWELL WILL BE REINVIGORATED AT TIMES NEXT WEEK, REMAINING
SOMEWHAT ELEVATED IN THE 8 TO 12 FOOT RANGE. PERIODS WILL BE MOSTLY
LONG.
&&
.CLIMATE...
THE WEEK 2 FORECAST FROM WPC INDICATES NEAR NORMAL PRECIPITATION
FOR US FOR THE LAST WEEK OF JANUARY. THIS IS BASED ON AN AREA OF
INTENSE TROPICAL CONVECTION THAT IS EXPECTED TO MOVE EAST FROM
INDONESIA TOWARD THE INTERNATIONAL DATELINE PROPAGATING OUT ROSSY
WAVE ENERGY THAT SHOULD UNDERCUT THE WEST COAST RIDGE. THIS IS
INDEED RELATED TO THE MJO. THERE HAVE BEEN HINTS OF THIS IN THE
LONG RANGE GUIDANCE OVER THE LAST 3 DAYS OR SO, BUT ALL
OPERATIONAL MODELS ARE NOT ON BOARD WITH THIS JUST YET. COUPLED
OCEAN-ATMOSPHERIC MODEL CONSENSUS INDICATES THIS RIPPLE WILL REACH
US CLOSER TO THE END OF THE MONTH, AROUND THE 30TH. AT THIS POINT
IT DOES APPEAR INCREASINGLY LIKELY THAT WE WILL SEE STORM ACTIVITY
RETURN TO OUR AREA AROUND THE END OF THE MONTH INTO THE FIRST WEEK
OF FEBRUARY. STAY TUNED, AS TIMING WITH SUCH FEATURES IS OFTEN
FICKLE. BTL
&&
.PREV DISCUSSION... /ISSUED 304 PM PST FRI JAN 17 2014/
SHORT TERM...EXPECT LITTLE CHANGE IN THE WEATHER PATTERN THIS
WEEKEND AS THE STRONG RIDGE CONTINUES TO GIVE US DRY AND STABLE
PATTERN. THERE WILL BE SMALL SUBTLE CHANGES EACH DAY DEPENDING ON
HOW HIGH THE INVERSION TOP IS AS WELL AS LOW LEVEL WINDS ABOVE THE
GROUND. FOR THIS WEEKEND BOTH GUIDANCE SHOW INVERSION HEIGHTS TO
BE SIMILAR EACH DAY BUT WITH A MORE VARIABLE WINDS LESS THAN 5 MPH
IN THE MIXED LAYER. AS A RESULT I DON`T SEE THE SURROUND HILLS OF
THE ROGUE VALLEY CLEARING..AND HAVE KEPT HIGHS RELATIVELY COOL.
OUTSIDE SW OREGON AND NORTHERN CALIFORNIA VALLEYS...MILD
TEMPERATURES WILL CONTINUE. AT THE COAST LOW LEVEL FLOW IS TURNING
AWAY FROM OFFSHORE EAST-NORTHEASTERLY. HIGHS MAY DECREASE CLOSER
TO SEASONAL NORMS ALTHOUGH THE COASTAL MOUNTAINS WILL CONTINUE TO
BE VERY WARM AND DRY THROUGH THE WEEKEND.
LONG TERM...TUESDAY THROUGH FRIDAY NIGHT.
LONG TERM MODELS ARE IN GOOD AGREEMENT...DEPICTING A VERY QUIET AND
DRY PATTERN UNDER HIGH PRESSURE THROUGHOUT THE LONG TERM...HOWEVER
SOLUTIONS ALSO DEPICT A WEAK CLOSED LOW PUSHING UNDERNEATH AN
AMPLIFIED EASTERN PACIFIC RIDGE AND ENTERING THE FORECAST AREA LATE
IN THE WEEK...ALTHOUGH AT THIS POINT THE FEATURE DOES NOT APPEAR
STRONG ENOUGH TO PRODUCE ANY MORE THAN SLIGHT CHANCES OF
PRECIPITATION OVER SOME OF THE RIDGES...OR TO BREAK THE INVERSION
AND SIGNIFICANTLY CLEAR THE FOG OR STAGNANT AIR FROM THE AREA
VALLEYS. /BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 4 AM PST SATURDAY FOR
ORZ023-024-026.
AIR STAGNATION ADVISORY UNTIL 4 AM PST SATURDAY FOR ORZ029>031.
FREEZING FOG ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ024-026.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
BTL
AREA FORECAST DISCUSSION
NWS MEDFORD OR
923 PM PST FRI JAN 17 2014
.UPDATE...
AN UPDATE HAS BEEN MADE THIS EVENING TO ADJUST TEMPERATURES,
MOSTLY DOWN, A BIT. ADJUSTMENTS WERE ALSO MADE TO ADDRESS SKY
COVER AND FOG RELATED TO A SOUTHERLY STRATUS SURGE OVER THE
COASTAL WATERS AND FROM THE WEST SLOPES OF THE COAST RANGE
WESTWARD. SKY AND FOG COVERAGE WAS ALSO FINE TUNED, PRIMARILY TO
ACCOUNT FOR A DENSE FREEZING FOG ADVISORY IN THE VALLEYS OF
JACKSON AND JOSEPHINE COUNTIES.
&&
.DISCUSSION...
A STRATUS SURGE HAS REACHED THE COAST FROM THE SOUTHWEST THIS
EVENING. THE ONLY MODEL THAT DID A GOOD JOB PICKING UP ON THIS
FEATURE IS THE HRRR-3KM, SO HAVE FOLLOWED IT WITH UPDATES THROUGH
THE MORNING.
ON SATURDAY WE DO EXPECT FOG WILL LIKELY DISSIPATE COMPLETELY
DURING THE AFTERNOON ACROSS ALL WEST SIDE VALLEYS DUE TO SOME
COOLING ABOVE THE BOUNDARY LAYER AND LESS SUBSIDENCE OVER THE
AREA. HOWEVER, THIS IS NOT A GUARANTEE, AS CHANGES ARE SUBTLE.
ALSO, IN SIMILAR PAST CASES, WITH THE FLOW ALOFT TURNING FROM
SOUTHEAST TO SOUTH TO SOUTHWEST, ROSEBURG OFTEN HAS A TOUGHER
TIME SHAKING THE STRATUS. HOWEVER, TRENDS IN TEMPERATURES AND THE
INVERSION TODAY SUGGEST IT SHOULD CLEAR FOR AT LEAST A FEW HOURS
IN THE AFTERNOON AND EVENING.
PLEASE SEE THE CLIMATE SECTION FOR LONG TERM INFORMATION.
&&
.AVIATION...BASED ON THE 18/00Z TAF CYCLE...
A SOUTHERLY STRATUS SURGE IS PUSHING TOWARD THE COAST AT THIS TIME.
WHILE MOST MODEL GUIDANCE SUGGESTS IT WILL NOT MAKE IT TO NORTH
BEND, CURRENT TRENDS AND THE HRRR 3KM MODEL DO INDEED HAVE IT MAKING
IT IN BEFORE THE SOUTHEAST DRAINAGE FLOW KICKS IN. THEREFORE, EXPECT
THAT NORTH BEND WILL LIKELY HAVE IFR STRATUS AND FOG THIS EVENING
THROUGH THE MORNING, AS WILL OTHER AREAS WEST OF AND ON THE WEST
SLOPES OF THE COAST RANGE. ELSEWHERE, FOG AND LOW CLOUDS OF THE LIFR
VARIETY ARE EXPECTED AGAIN IN THE SAME WEST SIDE VALLEYS AS THE LAST
FEW DAYS. ON THE EAST SIDE A SLIGHT RISE IN TEMPERATURES TONIGHT
MEANS FOG SHOULD BE A LITTLE LESS IN COVERAGE AND DURATION. A WEAKER
INVERSION DUE TO COOLING AT THE TOP OF THE BOUNDARY LAYER ON
SATURDAY MEANS ALL LOCATIONS WILL LIKELY CLEAR OUT. SIMILAR PAST
SCENARIOS INDICATE THAT ROSEBURG MAY BE THE LAST TO CLEAR SATURDAY
AFTERNOON.
&&
.MARINE...
SOUTH WINDS WILL BECOME NORTHERLY DURING THE DAYLIGHT HOURS OF
SATURDAY. LOW CLOUDS AND SOME FOG OVER THE WATERS TONIGHT SHOULD
LIFT TOWARD MORNING AND THROUGH THE DAY ON SATURDAY DUE TO COOLING
AT THE TOP OF THE BOUNDARY LAYER. WEST SWELL WILL BE ON THE INCREASE
THIS WEEKEND, LIKELY REACHING 10 FEET SATURDAY NIGHT INTO SUNDAY.
THIS WEST SWELL WILL BE REINVIGORATED AT TIMES NEXT WEEK, REMAINING
SOMEWHAT ELEVATED IN THE 8 TO 12 FOOT RANGE. PERIODS WILL BE MOSTLY
LONG.
&&
.CLIMATE...
THE WEEK 2 FORECAST FROM WPC INDICATES NEAR NORMAL PRECIPITATION
FOR US FOR THE LAST WEEK OF JANUARY. THIS IS BASED ON AN AREA OF
INTENSE TROPICAL CONVECTION THAT IS EXPECTED TO MOVE EAST FROM
INDONESIA TOWARD THE INTERNATIONAL DATELINE PROPAGATING OUT ROSSY
WAVE ENERGY THAT SHOULD UNDERCUT THE WEST COAST RIDGE. THIS IS
INDEED RELATED TO THE MJO. THERE HAVE BEEN HINTS OF THIS IN THE
LONG RANGE GUIDANCE OVER THE LAST 3 DAYS OR SO, BUT ALL
OPERATIONAL MODELS ARE NOT ON BOARD WITH THIS JUST YET. COUPLED
OCEAN-ATMOSPHERIC MODEL CONSENSUS INDICATES THIS RIPPLE WILL REACH
US CLOSER TO THE END OF THE MONTH, AROUND THE 30TH. AT THIS POINT
IT DOES APPEAR INCREASINGLY LIKELY THAT WE WILL SEE STORM ACTIVITY
RETURN TO OUR AREA AROUND THE END OF THE MONTH INTO THE FIRST WEEK
OF FEBRUARY. STAY TUNED, AS TIMING WITH SUCH FEATURES IS OFTEN
FICKLE. BTL
&&
.PREV DISCUSSION... /ISSUED 304 PM PST FRI JAN 17 2014/
SHORT TERM...EXPECT LITTLE CHANGE IN THE WEATHER PATTERN THIS
WEEKEND AS THE STRONG RIDGE CONTINUES TO GIVE US DRY AND STABLE
PATTERN. THERE WILL BE SMALL SUBTLE CHANGES EACH DAY DEPENDING ON
HOW HIGH THE INVERSION TOP IS AS WELL AS LOW LEVEL WINDS ABOVE THE
GROUND. FOR THIS WEEKEND BOTH GUIDANCE SHOW INVERSION HEIGHTS TO
BE SIMILAR EACH DAY BUT WITH A MORE VARIABLE WINDS LESS THAN 5 MPH
IN THE MIXED LAYER. AS A RESULT I DON`T SEE THE SURROUND HILLS OF
THE ROGUE VALLEY CLEARING..AND HAVE KEPT HIGHS RELATIVELY COOL.
OUTSIDE SW OREGON AND NORTHERN CALIFORNIA VALLEYS...MILD
TEMPERATURES WILL CONTINUE. AT THE COAST LOW LEVEL FLOW IS TURNING
AWAY FROM OFFSHORE EAST-NORTHEASTERLY. HIGHS MAY DECREASE CLOSER
TO SEASONAL NORMS ALTHOUGH THE COASTAL MOUNTAINS WILL CONTINUE TO
BE VERY WARM AND DRY THROUGH THE WEEKEND.
LONG TERM...TUESDAY THROUGH FRIDAY NIGHT.
LONG TERM MODELS ARE IN GOOD AGREEMENT...DEPICTING A VERY QUIET AND
DRY PATTERN UNDER HIGH PRESSURE THROUGHOUT THE LONG TERM...HOWEVER
SOLUTIONS ALSO DEPICT A WEAK CLOSED LOW PUSHING UNDERNEATH AN
AMPLIFIED EASTERN PACIFIC RIDGE AND ENTERING THE FORECAST AREA LATE
IN THE WEEK...ALTHOUGH AT THIS POINT THE FEATURE DOES NOT APPEAR
STRONG ENOUGH TO PRODUCE ANY MORE THAN SLIGHT CHANCES OF
PRECIPITATION OVER SOME OF THE RIDGES...OR TO BREAK THE INVERSION
AND SIGNIFICANTLY CLEAR THE FOG OR STAGNANT AIR FROM THE AREA
VALLEYS. /BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 4 AM PST SATURDAY FOR
ORZ023-024-026.
AIR STAGNATION ADVISORY UNTIL 4 AM PST SATURDAY FOR ORZ029>031.
FREEZING FOG ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ024-026.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
BTL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
137 AM EST SAT JAN 18 2014
.SYNOPSIS...
A STORM SYSTEM WILL FORM RAPIDLY OVER SOUTHEASTERN PA BEFORE
MOVING UP INTO NEW ENGLAND SATURDAY. OTHERWISE...A PROGRESSIVE
CYCLONIC FLOW PATTERN ALOFT WILL PERSIST ACROSS THE REGION FOR THE
NEXT SEVERAL DAYS....FEATURING THE PERIODIC PASSAGE OF SEVERAL
MOISTURE-STARVED ALBERTA CLIPPERS THAT WILL KEEP A NEARLY-CONSTANT
CHANCE OF LIGHT SNOW IN THE FORECAST. TEMPERATURES WILL BE
TRENDING NOTICEABLY COLDER INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
1130 PM...
SNOW BAND MOVING QUICKLY TO THE NORTHEAST AND WEAKENING QUITE A
BIT. NO LTG IN LAST HOUR AND A HALF. THE NEXT WAVE IS PUSHING
NORTHWARD INTO THE MID ATLANTIC THOUGH AND ALL SEEMS ON TRACK.
SNOW SHOULD INTENSIFY SLIGHTLY IN THE S-CENTRAL COS AND SLIDE NE.
TIMING ON BACK EDGE SEEMS TO BE ENDING BEFORE 09Z IN THE FAR SRN
TIER AND EVEN BEFORE 12Z IN AREAS S OF I-80 EXCEPT THE POCONOS.
THE FAR NE WILL HAVE TO WAIT UNTIL MID-MORNING TO SEE THE SNOW
TAPER OFF ACCORDING TO LATEST HRRR AND RUC. THE FAR SERN PART OF
LANCASTER CO MAY JUST GET A DUSTING...BUT HIGHER HILLS IN THE NE
WILL TAKE RUN AROUND 4 INCHES AS CSI BANDING SUPPORT IS
MAINTAINED IN THAT AREA FOR THE LONGEST PD. AGAIN...NO CHANGE
THERE. JUST TWEAKS TO TIMING.
9 PM...
THE VERY POTENT DYNAMICS ALOFT ARE RESULTING IN LOCALLY HEAVY
THUNDER-SNOW MOVING OUT OF THE LAURELS. THINKING HAS NOT CHANGED
APPRECIABLY...WITH A GENERALIZED 1-4 INCH SNOWFALL EXPECTED
OVERNIGHT AS THE VERY UNSTABLE AIRMASS AND STRONG FRONTOGENESIS
BRINGS A FAIRLY WIDESPREAD NUISANCE SNOW TO THE AREA.
FROM EARLIER...
HAVE DECIDED TO ISSUE AN ADVISORY FOR SEVERAL
INCHES OF SNOW STARTING LATER TONIGHT AND LASTING INTO SATURDAY
MORNING. LATEST GUIDANCE SHOWS THE EXPECTED RAPID DEVELOPMENT OF
THE SURFACE LOW AS IT PASSES THROUGH VA TOWARD SERN PA/DELMARVA
AREA. THIS RESULTS IN A PERIOD OF STRONG FRONTOGENETIC FORCING
THAT DEVELOPS OVER CENTRAL AND EASTERN PA. CAPPED BY STEEP MID
LEVEL LAPSE RATES EXCEEDING 7C/KM...THE ATMOSPHERE SHOULD BE VERY
EFFICIENT IN GENERATING UPWARD VERTICAL MOTION AND LIGHT TO
MODERATE SNOW DESPITE THE RELATIVE DRYNESS OF THE AIRMASS.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 AM SUNDAY/...
MAIN...WELL DEFINED SHORT WAVE WILL BE MOVING ACROSS PA DURING
THIS PERIOD WITH NEW AREA OF SNOW DEVELOPING AHEAD OF IT AS LEE
CYCLOGENESIS TAKES PLACE LATER TONIGHT. BOTH LATEST GFS AND NAM
DEPICT WEAK SFC WAVE DEVELOPING BETWEEN BWI AND PHL BY EARLY SAT
MORNING...WHICH CAUSED ME TO INCREASE QP AND SNOW AMOUNTS ACROSS
THE CWA...ESP EASTERN SECTIONS. BOTH THESE MODELS AND OTHER SHORT
RANGE GUIDANCE ALSO SHOW SEVERAL INCH SWATH OF SNOW ACROSS PARTS
OF CWA...BUT NOT COINCIDENT...DURING THE 06Z TO 12Z TIME FRAME.
DESPITE THIS INCREASE IN....DO NOT HAVE CONFIDENCE IN AMOUNTS
ENOUGH TO WARRANT THE NEED TO AN ADVISORY AT THIS TIME.
ANY STEADY SNOW WILL BE ENDING AROUND SUNRISE SATURDAY AS THE
MAIN TROF AXIS PULLS AWAY FROM PA...WITH LINGERING FLURRIES
POSSIBLE INTO SAT MORNING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
NOT MUCH TO ADD TO SATURDAY...SEE SECTION ABOVE.
FOR SATURDAY NIGHT...LEFT POPS CLOSE TO WHAT WAS IN THE GRIDS.
MAIN THING WAS NOT TO RUSH SNOW INTO NE AREAS TOO FAST BY
SUNDAY MORNING.
AS SOUTHERN WAVE MOVES OUT SUNDAY MORNING...MUCH OF THE AREA WILL
SEE SOME SUN BY AFT. IT WILL BE BREEZY OUT...AS THE NEXT SYSTEM
DROPS SE.
STRONG FRONT DROPS SE ACROSS THE AREA ON MONDAY. MAIN CHANGE
WAS TO UP TEMPS SOME PRIOR TO TUE...AS THE REAL COLD AIR IS
STILL TO THE WEST AND NORTH AT THIS POINT.
UNLIKE LAST EVENT...WINDS WILL NOT BE AS STRONG...AND COLD
AIR COMES IN MORE FROM THE NE INSTEAD OF BEING ADVECTED
IN FROM THE WEST. STILL DID LOWER TEMPS IN SOME SPOTS.
DID CUT BACK ON EXTENT OF SNOW SHOWERS SOME...MAIN AREA TO SEE
SOME SNOW SHOWERS WILL BE THE FAR NW...ALONG WITH THE UPSLOPE
AREAS OF THE WEST. SEE MENTION OF ICE COVER IN NEAR TERM
SECTION.
WENT WITH A DRY FCST FOR LATE IN THE WEEK...AS THE HIGH MOVES
EAST OF THE AREA.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A POTENT COLD FRONT IS PUSHING THRU CENTRAL PA EARLY THIS
AM...ACCOMPANIED BY A FEW HOURS OF SNOW SHOWERS AND IFR VSBYS.
RADAR IMAGE AT 06Z SHOWS BACK EDGE OF SIGNIFICANT SNOW IS JUST
ABOUT TO REACH KUNV AND KAOO. FURTHER WEST...DRIER FLOW BEHIND
FRONT HAS REACHED KJST AND BROUGHT MARKED IMPROVEMENT. HOWEVER...AT
KBFD THE IFR CONDS MAY LINGER UNTIL NEAR DAWN...THE RESULT OF
RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA.
FURTHER EAST...SNOW JUST ABOUT TO ARRIVE AT KIPT AND KMDT AS OF
06Z. NEAR TERM MDL DATA STILL SUPPORTS ARND 3 HRS OF IFR VSBYS AT
THESE LOCATIONS AS THE FRONTAL SNOW BAND MOVES THRU. KLNS MAY ALSO
SEE A BRIEF DIP TO IFR VSBYS BTWN 08Z-10Z. HOWEVER...RADAR/MODEL
TRENDS SUGGESTS THE BULK OF THE SNOW WILL PASS TO THEIR NORTH...SO
IFR CONDS NOT AS CERTAIN.
IN WAKE OF FROPA...GUSTY WNW WINDS OF 15-25KTS WILL BE THE MAIN
AVIATION CONCERN. SUCH WINDS ARE ALREADY BEING OBSERVED AT KJST AT
06Z AND SHOULD SPREAD EAST ACROSS THE REST OF CENTRAL PA LATER
THIS MORNING. GUSTY WINDS WILL SUBSIDE BY SAT EVENING...AS SFC
RIDGE BUILDS INTO THE STATE.
OUTLOOK...
SUN...AM SNOW/REDUCED VSBYS W MTNS. PM GUSTY WINDS WITH SHSN/REDUCED
VSBYS POSS NW MTNS.
MON...AM LGT SNOW/REDUCED VSBYS POSS N MTNS.
TUE-WED...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ006-012-037-041-042-045-046-049>053-058.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...DANGELO/GARTNER/MARTIN
LONG TERM...MARTIN
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1151 PM EST FRI JAN 17 2014
.SYNOPSIS...
A STORM SYSTEM WILL FORM RAPIDLY OVER SOUTHEASTERN PA BEFORE
MOVING UP INTO NEW ENGLAND SATURDAY. OTHERWISE...A PROGRESSIVE
CYCLONIC FLOW PATTERN ALOFT WILL PERSIST ACROSS THE REGION FOR THE
NEXT SEVERAL DAYS....FEATURING THE PERIODIC PASSAGE OF SEVERAL
MOISTURE-STARVED ALBERTA CLIPPERS THAT WILL KEEP A NEARLY-CONSTANT
CHANCE OF LIGHT SNOW IN THE FORECAST. TEMPERATURES WILL BE
TRENDING NOTICEABLY COLDER INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
1130 PM...
SNOW BAND MOVING QUICKLY TO THE NORTHEAST AND WEAKENING QUITE A
BIT. NO LTG IN LAST HOUR AND A HALF. THE NEXT WAVE IS PUSHING
NORTHWARD INTO THE MID ATLANTIC THOUGH AND ALL SEEMS ON TRACK.
SNOW SHOULD INTENSIFY SLIGHTLY IN THE S-CENTRAL COS AND SLIDE NE.
TIMING ON BACK EDGE SEEMS TO BE ENDING BEFORE 09Z IN THE FAR SRN
TIER AND EVEN BEFORE 12Z IN AREAS S OF I-80 EXCEPT THE POCONOS.
THE FAR NE WILL HAVE TO WAIT UNTIL MID-MORNING TO SEE THE SNOW
TAPER OFF ACCORDING TO LATEST HRRR AND RUC. THE FAR SERN PART OF
LANCASTER CO MAY JUST GET A DUSTING...BUT HIGHER HILLS IN THE NE
WILL TAKE RUN AROUND 4 INCHES AS CSI BANDING SUPPORT IS
MAINTAINED IN THAT AREA FOR THE LONGEST PD. AGAIN...NO CHANGE
THERE. JUST TWEAKS TO TIMING.
9 PM...
THE VERY POTENT DYNAMICS ALOFT ARE RESULTING IN LOCALLY HEAVY
THUNDER-SNOW MOVING OUT OF THE LAURELS. THINKING HAS NOT CHANGED
APPRECIABLY...WITH A GENERALIZED 1-4 INCH SNOWFALL EXPECTED
OVERNIGHT AS THE VERY UNSTABLE AIRMASS AND STRONG FRONTOGENESIS
BRINGS A FAIRLY WIDESPREAD NUISANCE SNOW TO THE AREA.
FROM EARLIER...
HAVE DECIDED TO ISSUE AN ADVISORY FOR SEVERAL
INCHES OF SNOW STARTING LATER TONIGHT AND LASTING INTO SATURDAY
MORNING. LATEST GUIDANCE SHOWS THE EXPECTED RAPID DEVELOPMENT OF
THE SURFACE LOW AS IT PASSES THROUGH VA TOWARD SERN PA/DELMARVA
AREA. THIS RESULTS IN A PERIOD OF STRONG FRONTOGENETIC FORCING
THAT DEVELOPS OVER CENTRAL AND EASTERN PA. CAPPED BY STEEP MID
LEVEL LAPSE RATES EXCEEDING 7C/KM...THE ATMOSPHERE SHOULD BE VERY
EFFICIENT IN GENERATING UPWARD VERTICAL MOTION AND LIGHT TO
MODERATE SNOW DESPITE THE RELATIVE DRYNESS OF THE AIRMASS.
&&
.SHORT TERM /7 AM SATURDAY THROUGH 6 AM SATURDAY/...
MAIN...WELL DEFINED SHORT WAVE WILL BE MOVING ACROSS PA DURING
THIS PERIOD WITH NEW AREA OF SNOW DEVELOPING AHEAD OF IT AS LEE
CYCLOGENESIS TAKES PLACE LATER TONIGHT. BOTH LATEST GFS AND NAM
DEPICT WEAK SFC WAVE DEVELOPING BETWEEN BWI AND PHL BY EARLY SAT
MORNING...WHICH CAUSED ME TO INCREASE QP AND SNOW AMOUNTS ACROSS
THE CWA...ESP EASTERN SECTIONS. BOTH THESE MODELS AND OTHER SHORT
RANGE GUIDANCE ALSO SHOW SEVERAL INCH SWATH OF SNOW ACROSS PARTS
OF CWA...BUT NOT COINCIDENT...DURING THE 06Z TO 12Z TIME FRAME.
DESPITE THIS INCREASE IN....DO NOT HAVE CONFIDENCE IN AMOUNTS
ENOUGH TO WARRANT THE NEED TO AN ADVISORY AT THIS TIME.
ANY STEADY SNOW WILL BE ENDING AROUND SUNRISE SATURDAY AS THE
MAIN TROF AXIS PULLS AWAY FROM PA...WITH LINGERING FLURRIES
POSSIBLE INTO SAT MORNING.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
NOT MUCH TO ADD TO SATURDAY...SEE SECTION ABOVE.
FOR SATURDAY NIGHT...LEFT POPS CLOSE TO WHAT WAS IN THE GRIDS.
MAIN THING WAS NOT TO RUSH SNOW INTO NE AREAS TOO FAST BY
SUNDAY MORNING.
AS SOUTHERN WAVE MOVES OUT SUNDAY MORNING...MUCH OF THE AREA WILL
SEE SOME SUN BY AFT. IT WILL BE BREEZY OUT...AS THE NEXT SYSTEM
DROPS SE.
STRONG FRONT DROPS SE ACROSS THE AREA ON MONDAY. MAIN CHANGE
WAS TO UP TEMPS SOME PRIOR TO TUE...AS THE REAL COLD AIR IS
STILL TO THE WEST AND NORTH AT THIS POINT.
UNLIKE LAST EVENT...WINDS WILL NOT BE AS STRONG...AND COLD
AIR COMES IN MORE FROM THE NE INSTEAD OF BEING ADVECTED
IN FROM THE WEST. STILL DID LOWER TEMPS IN SOME SPOTS.
DID CUT BACK ON EXTENT OF SNOW SHOWERS SOME...MAIN AREA TO SEE
SOME SNOW SHOWERS WILL BE THE FAR NW...ALONG WITH THE UPSLOPE
AREAS OF THE WEST. SEE MENTION OF ICE COVER IN NEAR TERM
SECTION.
WENT WITH A DRY FCST FOR LATE IN THE WEEK...AS THE HIGH MOVES
EAST OF THE AREA.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SNOW BAND HAS WEAKENED SOME AND IS MOVG SLOWER TO THE ENE.
THEREFORE ISSUED SEVERAL AMDS TO REFLECT SLIGHTLY BETTER VISBY
TRENDS AND LATER TOA OF -SN ACRS THE ERN AIRFIELDS.
A RATHER COMPACT BUT ROBUST MID/UPPER LEVEL TROUGH WILL PIVOT ACRS
THE CENTRAL APPLCHNS LATE THIS EVE AND TAKE ON A NEGATIVE TILT AS
IT LIFTS NEWD THRU THE NRN MID-ATLC STATES LATE TONIGHT INTO EARLY
SAT. THIS POTENT ENERGY ALOFT WILL BE SUFFICIENT TO INDUCE A
DISTINCT SFC LOW THAT WILL RIDE NWD ALONG AN ATTENDANT COLD FRONT
FROM NRN VA INTO NERN PA BY 12Z SAT. A RELATIVELY NARROW AND
PROGRESSIVE AXIS OF SNOW WILL DEVELOP AND MOVE OVER THE AIRSPACE
WHICH SHOULD BRING A SEVERAL HOUR PERIOD OF REDUCED CONDS FOLLOWED
BY GUSTY WNW WINDS 15-25KTS ON THE BACKSIDE OF THE DEPARTING LOW
CENTER. THE SNOW WILL END FROM SW-NE EARLY SAT MORNING BUT GUSTY
WINDS WILL PERSIST INTO THE AFTN...BEFORE SUBSIDING INTO SAT NGT
AS RIDGE OF HIGH PRES QUICKLY SLIDES THRU CENTRAL PA.
OUTLOOK...
SUN...IFR/MVFR IN -SHSN WRN AND CNTRL AIRFIELDS. MVFR PSBL ERN
SXNS. GUSTY WSW WINDS...BCMG WNW SUN NGT.
MON...IFR/MVFR WITH OCNL -SHSN WRN SXNS...MAINLY VFR E OF THE MTNS.
TUE-WED...MVFR WEST -SHSN PSBL. MAINLY VFR CENTRAL/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST SATURDAY FOR PAZ006-012-
037-041-042-045-046-049>053-058.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...DANGELO/GARTNER/MARTIN
LONG TERM...MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1149 PM EST FRI JAN 17 2014
.SYNOPSIS...
A STORM SYSTEM WILL FORM RAPIDLY OVER SOUTHEASTERN PA BEFORE
MOVING UP INTO NEW ENGLAND SATURDAY. OTHERWISE...A PROGRESSIVE
CYCLONIC FLOW PATTERN ALOFT WILL PERSIST ACROSS THE REGION FOR THE
NEXT SEVERAL DAYS....FEATURING THE PERIODIC PASSAGE OF SEVERAL
MOISTURE-STARVED ALBERTA CLIPPERS THAT WILL KEEP A NEARLY-CONSTANT
CHANCE OF LIGHT SNOW IN THE FORECAST. TEMPERATURES WILL BE
TRENDING NOTICEABLY COLDER INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
1130 PM...
SNOW BAND MOVING QUICKLY TO THE NORTHEAST AND WEAKENING QUITE A
BIT. NO LTG IN LAST HOUR AND A HALF. THE NEXT WAVE IS PUSHING
NORTHWARD INTO THE MID ATLANTIC THOUGH AND ALL SEEMS ON TRACK.
SNOW SHOULD INTENSIFY SLIGHTLY IN THE S-CENTRAL COS AND SLIDE NE.
TIMING ON BACK EDGE SEEMS TO BE ENDING BEFORE 09Z IN THE FAR SRN
TIER AND EVEN BEFORE 12Z IN AREAS S OF I-80 EXCEPT THE POCONOS.
THE FAR NE WILL HAVE TO WAIT UNTIL MID-MORNING TO SEE THE SNOW
TAPER OFF ACCORDING TO LATEST HRRR AND RUC. THE FAR SERN PART OF
LANCASTER CO MAY JUST GET A DUSTING...BUT HIGHER HILLS IN THE NE
WILL TAKE RUN AROUND 4 INCHES AS CSI BANDING SUPPORT IS
MAINTAINED IN THAT AREA FOR THE LONGEST PD. AGAIN...NO CHANGE
THERE. JUST TWEAKS TO TIMING.
9 PM...
THE VERY POTENT DYNAMICS ALOFT ARE RESULTING IN LOCALLY HEAVY
THUNDER-SNOW MOVING OUT OF THE LAURELS. THINKING HAS NOT CHANGED
APPRECIABLY...WITH A GENERALIZED 1-4 INCH SNOWFALL EXPECTED
OVERNIGHT AS THE VERY UNSTABLE AIRMASS AND STRONG FRONTOGENESIS
BRINGS A FAIRLY WIDESPREAD NUISANCE SNOW TO THE AREA.
FROM EARLIER...
HAVE DECIDED TO ISSUE AN ADVISORY FOR SEVERAL
INCHES OF SNOW STARTING LATER TONIGHT AND LASTING INTO SATURDAY
MORNING. LATEST GUIDANCE SHOWS THE EXPECTED RAPID DEVELOPMENT OF
THE SURFACE LOW AS IT PASSES THROUGH VA TOWARD SERN PA/DELMARVA
AREA. THIS RESULTS IN A PERIOD OF STRONG FRONTOGENETIC FORCING
THAT DEVELOPS OVER CENTRAL AND EASTERN PA. CAPPED BY STEEP MID
LEVEL LAPSE RATES EXCEEDING 7C/KM...THE ATMOSPHERE SHOULD BE VERY
EFFICIENT IN GENERATING UPWARD VERTICAL MOTION AND LIGHT TO
MODERATE SNOW DESPITE THE RELATIVE DRYNESS OF THE AIRMASS.
&&
.SHORT TERM /7 AM SATURDAY THROUGH 6 AM SATURDAY/...
MAIN...WELL DEFINED SHORT WAVE WILL BE MOVING ACROSS PA DURING
THIS PERIOD WITH NEW AREA OF SNOW DEVELOPING AHEAD OF IT AS LEE
CYCLOGENESIS TAKES PLACE LATER TONIGHT. BOTH LATEST GFS AND NAM
DEPICT WEAK SFC WAVE DEVELOPING BETWEEN BWI AND PHL BY EARLY SAT
MORNING...WHICH CAUSED ME TO INCREASE QP AND SNOW AMOUNTS ACROSS
THE CWA...ESP EASTERN SECTIONS. BOTH THESE MODELS AND OTHER SHORT
RANGE GUIDANCE ALSO SHOW SEVERAL INCH SWATH OF SNOW ACROSS PARTS
OF CWA...BUT NOT COINCIDENT...DURING THE 06Z TO 12Z TIME FRAME.
DESPITE THIS INCREASE IN....DO NOT HAVE CONFIDENCE IN AMOUNTS
ENOUGH TO WARRANT THE NEED TO AN ADVISORY AT THIS TIME.
ANY STEADY SNOW WILL BE ENDING AROUND SUNRISE SATURDAY AS THE
MAIN TROF AXIS PULLS AWAY FROM PA...WITH LINGERING FLURRIES
POSSIBLE INTO SAT MORNING.
&&
.LONG TERM /SATURDAY THROUGH FRIDAY/...
NOT MUCH TO ADD TO SATURDAY...SEE SECTION ABOVE.
FOR SATURDAY NIGHT...LEFT POPS CLOSE TO WHAT WAS IN THE GRIDS.
MAIN THING WAS NOT TO RUSH SNOW INTO NE AREAS TOO FAST BY
SUNDAY MORNING.
AS SOUTHERN WAVE MOVES OUT SUNDAY MORNING...MUCH OF THE AREA WILL
SEE SOME SUN BY AFT. IT WILL BE BREEZY OUT...AS THE NEXT SYSTEM
DROPS SE.
STRONG FRONT DROPS SE ACROSS THE AREA ON MONDAY. MAIN CHANGE
WAS TO UP TEMPS SOME PRIOR TO TUE...AS THE REAL COLD AIR IS
STILL TO THE WEST AND NORTH AT THIS POINT.
UNLIKE LAST EVENT...WINDS WILL NOT BE AS STRONG...AND COLD
AIR COMES IN MORE FROM THE NE INSTEAD OF BEING ADVECTED
IN FROM THE WEST. STILL DID LOWER TEMPS IN SOME SPOTS.
DID CUT BACK ON EXTENT OF SNOW SHOWERS SOME...MAIN AREA TO SEE
SOME SNOW SHOWERS WILL BE THE FAR NW...ALONG WITH THE UPSLOPE
AREAS OF THE WEST. SEE MENTION OF ICE COVER IN NEAR TERM
SECTION.
WENT WITH A DRY FCST FOR LATE IN THE WEEK...AS THE HIGH MOVES
EAST OF THE AREA.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
INTENSE BAND OF +SN IS MOVG ACRS CNTRL SXNS LATE THIS EVE. +TSSN
WAS REPORTED EARLIER AT JST. EXPECT VIS TO DROP BLW AIRFIELD MINS
AT UNV BTWN 04-05Z. FOR THE 03Z UPDATE...ADJUSTED TOA OF -SN OVER
ERN TERMINALS DUE TO SLOWER TIMING /LATER ARRIVAL/ AND ISSUED
AMDS AS SNOW INTENSITY TAPERED OFF AT JST.
A RATHER COMPACT BUT ROBUST MID/UPPER LEVEL TROUGH WILL PIVOT ACRS
THE CENTRAL APPLCHNS LATE THIS EVE AND TAKE ON A NEGATIVE TILT AS
IT LIFTS NEWD THRU THE NRN MID-ATLC STATES LATE TONIGHT INTO EARLY
SAT. THIS POTENT ENERGY ALOFT WILL BE SUFFICIENT TO INDUCE A
DISTINCT SFC LOW THAT WILL RIDE NWD ALONG AN ATTENDANT COLD FRONT
FROM NRN VA INTO NERN PA BY 12Z SAT. A RELATIVELY NARROW AND
PROGRESSIVE AXIS OF SNOW WILL DEVELOP AND MOVE OVER THE AIRSPACE
WHICH SHOULD BRING A SEVERAL HOUR PERIOD OF REDUCED CONDS FOLLOWED
BY GUSTY WNW WINDS 15-25KTS ON THE BACKSIDE OF THE DEPARTING LOW
CENTER. THE SNOW WILL END FROM SW-NE EARLY SAT MORNING BUT GUSTY
WINDS WILL PERSIST INTO THE AFTN...BEFORE SUBSIDING INTO SAT NGT
AS RIDGE OF HIGH PRES QUICKLY SLIDES THRU CENTRAL PA.
OUTLOOK...
SUN...IFR/MVFR IN -SHSN WRN AND CNTRL AIRFIELDS. MVFR PSBL ERN
SXNS. GUSTY WSW WINDS...BCMG WNW SUN NGT.
MON...IFR/MVFR WITH OCNL -SHSN WRN SXNS...MAINLY VFR E OF THE MTNS.
TUE-WED...MVFR WEST -SHSN PSBL. MAINLY VFR CENTRAL/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM EST SATURDAY FOR PAZ006-012-
037-041-042-045-046-049>053-058.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...DANGELO/GARTNER/MARTIN
LONG TERM...MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
529 PM CST SUN JAN 19 2014
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 250 PM CST SUN JAN 19 2014
CHALLENGING PCPN FORECAST TONIGHT AND MONDAY.
POSITIVES FOR PCPN - SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN
GREAT LAKES TONIGHT...NUDGING A COLD FRONT OVER NORTHERN WI SOUTH.
WEAK FRONTOGENETIC FORCING AROUND THE BOUNDARY. ANOTHER SHORTWAVE
WILL DROP ACROSS IOWA MON AFTERNOON/EVENING...WITH SOME QG
CONVERGENCE ASSOCIATED WITH IT.
NEGATIVES FOR PCPN - NOT MUCH THERMODYNAMICS AHEAD OF EITHER UPPER
LEVEL FEATURE WITH MOSTLY LOW LEVEL COLD AIR ADVECTION THROUGH 12Z
TUE. SOME HINTS OF ISENTROPIC UPGLIDE...BUT DISJOINTED. SATURATION
IS FAIRLY SHALLOW...MOSTLY SUB 600 MB.
BELIEVE THERE WILL BE SOME PCPN ACROSS THE AREA TONIGHT THROUGH
MONDAY...BUT WHERE AND HOW WIDESPREAD IS FAR FROM CERTAIN. FEEL THE
BEST CHANCES WILL BE TIED WITH EITHER SHORTWAVE. MORE COMFORTABLE
GOING HIGH CHANCE POPS THROUGH THE PERIOD...AS ANY MODEL CONSENSUS
FAVORS MN/IA WITH THE BEST CHANCES. EXPECT ADJUSTMENTS TO THE PCPN
CHANCES AS TRENDS BECOME CLEARER.
ASSUMING PCPN DOES FALL...PTYPE IS A QUESTION MARK. SHALLOW NATURE
OF THE SATURATION RAISES CONCERNS OF WHETHER ICE WILL BE IN THE
CLOUD - AND IF NOT...DRIZZLE IS FAVORED. THIS LOOKS MORE LIKELY
TONIGHT AS THE SFC FRONT SLOWLY SINKS SOUTH. IF ENOUGH LIFT WITH THE
BOUNDARY...DRIZZLE COULD DEVELOP. FORCING IS VERY MEAGER
THOUGH...AND DON/T SEE THE WARM AIR ADVECTION THAT IS USUALLY
PRESENT IN WIDESPREAD DRIZZLE EVENTS. STILL...IF IT FALLS...ITS
PROBABLY DRIZZLE. ENOUGH COLD AIR MOVING IN BY MONDAY MORNING - AND
SOME DEEPENING TO THE CLOUD LAYER - THAT SNOW SHOULD BE THE PTYPE.
AGAIN - ITS A TOUGH FORECAST. BEST CHANCES WILL LIE WEST OF THE
FORECAST AREA ON MONDAY. WHATEVER WOULD FALL WILL BE MINIMAL...BUT
IF ITS FREEZING...LIGHT ICING COULD OCCUR WHICH WOULD RESULT IN SOME
DRIVING ETC DIFFICULTIES.
PUNCH OF COLD AIR MOVES IN MONDAY NIGHT...BETWEEN THE DEPARTING
SHORTWAVE AND AN AREA OF HIGH PRESSURE OVER THE PLAINS. 850 MB TEMPS
PROGGED TO FALL TO AROUND -22 C. COUPLE THIS WITH A TIGHTENING
PRESSURE GRADIENT...THUS STRONGER WINDS...AND DANGEROUS WIND CHILLS
FROM 20 TO 30 BELOW ARE LIKELY. UNLESS THE SCENARIO CHANGES
SIGNIFICANTLY...A WIND CHILL ADVISORY WILL BE NEEDED FOR MON
NIGHT/TUE MORNING FOR THE ENTIRE FORECAST AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 PM CST SUN JAN 19 2014
LONG WAVE UPPER LEVEL TROUGH ISN/T GOING ANYWHERE FOR THE UPCOMING
WEEK...WITH THE UPPER LEVEL RIDGE FIRMLY PLANTED OVER THE WEST
COAST. SHORTWAVES WILL TOP THE RIDGE...AND DROP THROUGH THE
TROUGH...PERIODICALLY SPINNING ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY. LIGHT SNOW CHANCES WILL RESULT...WITH THE USUAL
TIMING/POSITIONING CHALLENGES FROM A FLOW SUCH AS THIS. TEMPERATURES
WILL ALSO STAY COLD AS ARCTIC AIR HAS A CLEAR AVENUE TO THE SOUTH.
NAM/GFS/ECMWF ALL IN GOOD AGREEMENT WITH DROPPING A SHORTWAVE
SOUTHWARD ACROSS THE REGION TUE NIGHT/WED. STRONG SLUG OF QG
CONVERGENCE WITH THE SHORTWAVE...WITH SOME LOW LEVEL WARM AIR
ADVECTION AND ISENTROPIC UPGLIDE LEADING THE FEATURE. THERE MIGHT BE
SOME CHALLENGES WHEN IT COMES TO SATURATION AS X-SECTIONS AND BUFKIT
SOUNDINGS VIA THE GFS AND NAM KEEPING THE BULK OF THE MOISTURE SUB
600 MB. DEEP ENOUGH FOR SNOW...BUT MAYBE NOT DEEP ENOUGH FOR A MORE
EFFICIENT PCPN PRODUCER. THAT SAID...THE GFS DEPICTS A DEEP
DENDRITIC ZONE GROWTH REGION...AND ITS FAIRLY ISOTHERMAL IN THIS
SWEET SPOT. WHILE THE OMEGA ISN/T THAT STRONG...ITS THROUGH THE
SATURATED COLUMN. THIS IS PEAK DURING THE OVERNIGHT HOURS TUE. SNOW
IS LOOKING MORE LIKELY IN THE TUE NIGHT-WED TIME FRAME.
LIGHT...FLUFFY ACCUMS OF 1 TO 2 INCHES WITH RATIOS OF 20/30 TO 1
LOOK REASONABLE.
GOOD SURGE OF COLD LOW LEVEL AIR POST THE SHORTWAVE
WED NIGHT/THU...WITH 850 MB TEMPS FALLING TO AROUND -22 C AND
ANOMALIES VIA THE GFS ENSEMBLES OF -1 TO -2. IT WILL BE A VERY COLD
MORNING THURSDAY FOR THE REGION. A TIGHT PRESSURE GRADIENT BETWEEN
THE DEPARTING LOW AND A HIGH OVER THE PLAINS WILL MAKE IT FEEL
COLDER...WITH WIND CHILLS FROM -20 TO -30 F. A WIND CHILL ADV FOR
WED NIGHT/THU MORNING IS LIKELY.
THE NEXT UPPER LEVEL SHORTWAVE TROUGH IS SLATED TO DROP ACROSS THE
NORTHERN GREAT LAKES THU NIGHT/FRI. THE BULK OF THE UPPER LEVEL
ENERGY HOLDS TO THE NORTH...AND THUS SO WOULD THE BETTER PCPN
CHANCES. HOWEVER...MODELS HINT AT A SECONDARY BIT OF ENERGY
STREAKING DOWN THE MEAN TROUGH...AND ACROSS THE FORECAST AREA FRI
AFTERNOON/NIGHT. COULD BE SOME SNOW CHANCES WITH THIS...ALTHOUGH
CONFIDENCE ON TIMING/POSITIONING NOT HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 529 PM CST SUN JAN 19 2014
THE COLD FRONT WAS OVER NORTHERN WISCONSIN INTO CENTRAL MINNESOTA
LATE THIS AFTERNOON. MVFR CEILINGS WERE IN PLACE JUST AHEAD OF AND
BEHIND THE FRONT. THE 19.18Z NAM INDICATES THIS FRONT WILL BE VERY
SLOW TO MOVE SOUTH OVERNIGHT SO HAVE PUSHED BACK THE ARRIVAL TIME
OF THE MVFR CEILINGS TO LATE TONIGHT AND THEN BRING THE WIND SHIFT
WITH THE FRONT THROUGH AROUND 12Z. THE NAM AND 19.21Z RAP CONTINUE
TO SUGGEST THE POTENTIAL FOR SOME FREEZING DRIZZLE WHEN THE MVFR
CEILINGS ARRIVE...BUT STILL NOT SOLD ON THIS OCCURRING. NOT SURE
WHERE THE FORCING IN THE SATURATED LAYER IS GOING TO COME FROM AS
THERE IS BROAD SCALE LOW LEVEL COLD AIR ADVECTION GOING ON AND NO
FRONTOGENESIS IN THE 1000-850 MB LAYER. COULD BE SOME LIGHT SNOW
OR FLURRIES ONCE THE FRONT GOES THROUGH AND WILL SHOW SOME
FLURRIES THROUGH THE DAY WITHOUT ANY VISIBILITY RESTRICTION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 AM CST SAT JAN 18 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CST SAT JAN 18 2014
MAIN FORECAST CONCERN THROUGH THE SHORT TERM CENTERED ON
ACCUMULATING SNOW TODAY.
WATER VAPOR/SURFACE ANALYSIS SHOW VIGOROUS LOW PRESSURE MOVING OUT
OF EASTERN ND SOUTHEAST INTO MN. RADAR AND SURFACE OBSERVATIONS
SHOWING AN EXPANSIVE NW-SE BAND OF LIGHT TO MODERATE SNOWFALL IN
ADVANCE OF THE LOW AND ATTENDANT WARM FRONTAL BOUNDARY EXTENDING
ACROSS MOST OF MN. INDICATION OF THE STRONG BAROCLINICITY ASSOCIATED
WITH THIS WAVE EVIDENCED BY TEMPERATURES RANGING FROM THE 30S ACROSS
THE DAKOTAS TO READINGS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW
ZERO ACROSS THE NWS LA CROSSE FORECAST AREA.
MODELS ALL HONED INTO PROGGED TRACK OF THE LOW...TAKING IT SOUTHEAST
INTO SOUTH CENTRAL MN BY 12Z AND THEN INTO CENTRAL IL BY SUN 00Z.
DYNAMICS FAIRLY IMPRESSIVE WITH THE SYSTEM WITH STRONG ISENTROPIC
LIFT INDICATED BY RAP ON THE 275K SURFACE AND WEAK TO MODERATE
FRONTOGENETIC FORCING IN THE 1000-700MB LAYER. BUFKIT ALSO SHOWING
AROUND 17 MICROBARS OF LIFT THROUGH THE DENDRITIC GROWTH ZONE AT
KRST EARLY ON THIS MORNING. SNOW TO LIQUID RATIOS SHOULD BE FAIRLY
HIGH AS A RESULT...SOMEWHERE IN THE 16-18 TO 1 RANGE. GIVEN THIS AND
THE TRACK OF THE LOW...HEAVIEST SNOW BAND WILL SET UP ALONG AN AXIS
FROM DODGE CENTER AND ROCHESTER THROUGH DUBUQUE IA WHERE AROUND 4 TO
LOCALLY 5 INCHES IS EXPECTED THROUGH THE DAY. AS A RESULT...A WINTER
WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM THIS EVENING FOR ALL
OF SOUTHEAST MN/NORTHEAST IA..AND COUNTIES IN WI BORDERING THE
MISSISSIPPI AND WISCONSIN RIVERS. LOOKS LIKE MOST OF THE
ACCUMULATING SNOW MAY BE DONE/SHIFTED SOUTHEAST OF THE AREA BEFORE
6PM...BUT SOME DRIFTING OF THE SNOW WITH INCREASING NORTH WINDS ON
THE BACKSIDE OF THE LOW MAY STILL CAUSE SOME DRIVING
DIFFICULTIES...SO WILL LET IT UP THE THE DAYSHIFT TO ASSESS THE
STATUS OF THE ADVISORY HEADLINE GOING INTO THE AFTERNOON.
OTHERWISE...TEMPERATURES TODAY EXPECTED TO MODERATE INTO THE UPPER
TEENS TO MIDDLE 20S.
A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA TONIGHT WITH WARM AIR
ADVECTION KICKING IN AFTER MIDNIGHT. LOOK FOR LOWS OCCURRING AROUND
MIDNIGHT IN THE UPPER SINGLE DIGITS/LOWER TEENS...THEN SLOWING
CLIMBING THROUGH THE TEENS AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT JAN 18 2014
MILDER DAY ON TAP FOR SUNDAY AS WARM AIR ADVECTION CONTINUES IN
ADVANCE OF A COLD FRONT MOVING SOUTHWARD OUT OF CANADA INTO NORTHERN
WI. LOOK FOR HIGHS TOPPING OFF IN THE MIDDLE 20S TO THE MIDDLE 30S.
THE COLD FRONT WILL CONTINUE MOVING SLOWLY SOUTHWARD ACROSS THE AREA
SUNDAY NIGHT AS A WEAK MID-LEVEL WAVE RIPPLES ALONG THE BAROCLINIC
ZONE IN PLACE. THIS WILL GIVE THE AREA A CHANCE FOR SOME VERY LIGHT
SNOWFALL.
THE COLD FRONT WILL ALSO MARK THE TRANSITION BACK TO COLDER THAN
NORMAL NORTHWEST FLOW GRIPPING THE REGION AGAIN. MODELS ALSO SHOW
VARIOUS EMBEDDED SHORTWAVE TROUGHS WITHIN THE FLOW FOR ON/OFF LIGHT
SNOW CHANCES THROUGH FRIDAY. CONFIDENCE ON TIMING THESE WAVES PRETTY
LOW AT THIS TIME WITH VARIOUS MODEL SOLUTIONS. OTHERWISE...LOOK FOR
HIGH TEMPERATURES GENERALLY IN THE SINGLE DIGITS AND TEENS ABOVE
ZERO WITH LOWS IN THE SINGLE DIGITS AND TEENS BELOW ZERO. APPEARS
WIND CHILL HEADLINES WILL LIKELY BE NEEDED MONDAY NIGHT/TUESDAY
MORNING AS WIND CHILL VALUES DIP INTO THE 20S TO NEAR 30 BELOW ZERO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1100 AM CST SAT JAN 18 2014
SNOW HAS ENDED FOR KRST...BUT COULD LINGER UNTIL 19-20Z AT KLSE.
DON/T EXPECT MUCH ACCUMS AT KLSE AFTER 18Z THOUGH...AND VSBYS AND
CIGS WILL BE ON AN IMPROVING TREND.
LATEST SATELLITE IMAGERY/SFC OBS SHOW CLEAR SKIES OVER MOST OF
CENTRAL/NORTHERN MN...ROTATING SOUTHEAST. CLOUDS STILL HANGING
ACROSS NORTHWEST WI...BUT GENERALLY VFR. STRONG SUBSIDENCE POST THE
LOW PRESSURE SYSTEM WAS RESPONSIBLE FOR THE CLEARING OVER MN...AND
EXPECT A PERIOD OF SCT/SKC LATER THIS AFTERNOON - PERSISTING INTO
THE EVENING. TRENDS ALSO FAVOR VFR CIGS FOR THE REST OF TODAY AND
TONIGHT. THAT SAID...MODELS WANT TO HANG ONTO SOME LOW SATURATION
PER RH FIELDS AND BUFKIT SOUNDINGS TONIGHT. SOME MVFR CIGS OVER THE
NORTHERN PLAINS...BUT THINK THAT WILL SINK SOUTH/SOUTHEAST...AWAY
FROM THE TAF SITES. SO GOING TO LEAN ON THE OPTIMISTIC-SIDE FOR THE
TAFS.
WINDS WILL INCREASE FROM THE SOUTHWEST TONIGHT...BECOMING MORE WEST
ON SUNDAY. SOME MID LEVEL CLOUDS WILL ALSO RETURN LATER
TONIGHT...AHEAD OF A SHORTWAVE TROUGH TRACKING ACROSS SOUTHERN
CANADA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032-
033-041-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
514 AM CST SAT JAN 18 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CST SAT JAN 18 2014
MAIN FORECAST CONCERN THROUGH THE SHORT TERM CENTERED ON
ACCUMULATING SNOW TODAY.
WATER VAPOR/SURFACE ANALYSIS SHOW VIGOROUS LOW PRESSURE MOVING OUT
OF EASTERN ND SOUTHEAST INTO MN. RADAR AND SURFACE OBSERVATIONS
SHOWING AN EXPANSIVE NW-SE BAND OF LIGHT TO MODERATE SNOWFALL IN
ADVANCE OF THE LOW AND ATTENDANT WARM FRONTAL BOUNDARY EXTENDING
ACROSS MOST OF MN. INDICATION OF THE STRONG BAROCLINICITY ASSOCIATED
WITH THIS WAVE EVIDENCED BY TEMPERATURES RANGING FROM THE 30S ACROSS
THE DAKOTAS TO READINGS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW
ZERO ACROSS THE NWS LA CROSSE FORECAST AREA.
MODELS ALL HONED INTO PROGGED TRACK OF THE LOW...TAKING IT SOUTHEAST
INTO SOUTH CENTRAL MN BY 12Z AND THEN INTO CENTRAL IL BY SUN 00Z.
DYNAMICS FAIRLY IMPRESSIVE WITH THE SYSTEM WITH STRONG ISENTROPIC
LIFT INDICATED BY RAP ON THE 275K SURFACE AND WEAK TO MODERATE
FRONTOGENETIC FORCING IN THE 1000-700MB LAYER. BUFKIT ALSO SHOWING
AROUND 17 MICROBARS OF LIFT THROUGH THE DENDRITIC GROWTH ZONE AT
KRST EARLY ON THIS MORNING. SNOW TO LIQUID RATIOS SHOULD BE FAIRLY
HIGH AS A RESULT...SOMEWHERE IN THE 16-18 TO 1 RANGE. GIVEN THIS AND
THE TRACK OF THE LOW...HEAVIEST SNOW BAND WILL SET UP ALONG AN AXIS
FROM DODGE CENTER AND ROCHESTER THROUGH DUBUQUE IA WHERE AROUND 4 TO
LOCALLY 5 INCHES IS EXPECTED THROUGH THE DAY. AS A RESULT...A WINTER
WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM THIS EVENING FOR ALL
OF SOUTHEAST MN/NORTHEAST IA..AND COUNTIES IN WI BORDERING THE
MISSISSIPPI AND WISCONSIN RIVERS. LOOKS LIKE MOST OF THE
ACCUMULATING SNOW MAY BE DONE/SHIFTED SOUTHEAST OF THE AREA BEFORE
6PM...BUT SOME DRIFTING OF THE SNOW WITH INCREASING NORTH WINDS ON
THE BACKSIDE OF THE LOW MAY STILL CAUSE SOME DRIVING
DIFFICULTIES...SO WILL LET IT UP THE THE DAYSHIFT TO ASSESS THE
STATUS OF THE ADVISORY HEADLINE GOING INTO THE AFTERNOON.
OTHERWISE...TEMPERATURES TODAY EXPECTED TO MODERATE INTO THE UPPER
TEENS TO MIDDLE 20S.
A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA TONIGHT WITH WARM AIR
ADVECTION KICKING IN AFTER MIDNIGHT. LOOK FOR LOWS OCCURRING AROUND
MIDNIGHT IN THE UPPER SINGLE DIGITS/LOWER TEENS...THEN SLOWING
CLIMBING THROUGH THE TEENS AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT JAN 18 2014
MILDER DAY ON TAP FOR SUNDAY AS WARM AIR ADVECTION CONTINUES IN
ADVANCE OF A COLD FRONT MOVING SOUTHWARD OUT OF CANADA INTO NORTHERN
WI. LOOK FOR HIGHS TOPPING OFF IN THE MIDDLE 20S TO THE MIDDLE 30S.
THE COLD FRONT WILL CONTINUE MOVING SLOWLY SOUTHWARD ACROSS THE AREA
SUNDAY NIGHT AS A WEAK MID-LEVEL WAVE RIPPLES ALONG THE BAROCLINIC
ZONE IN PLACE. THIS WILL GIVE THE AREA A CHANCE FOR SOME VERY LIGHT
SNOWFALL.
THE COLD FRONT WILL ALSO MARK THE TRANSITION BACK TO COLDER THAN
NORMAL NORTHWEST FLOW GRIPPING THE REGION AGAIN. MODELS ALSO SHOW
VARIOUS EMBEDDED SHORTWAVE TROUGHS WITHIN THE FLOW FOR ON/OFF LIGHT
SNOW CHANCES THROUGH FRIDAY. CONFIDENCE ON TIMING THESE WAVES PRETTY
LOW AT THIS TIME WITH VARIOUS MODEL SOLUTIONS. OTHERWISE...LOOK FOR
HIGH TEMPERATURES GENERALLY IN THE SINGLE DIGITS AND TEENS ABOVE
ZERO WITH LOWS IN THE SINGLE DIGITS AND TEENS BELOW ZERO. APPEARS
WIND CHILL HEADLINES WILL LIKELY BE NEEDED MONDAY NIGHT/TUESDAY
MORNING AS WIND CHILL VALUES DIP INTO THE 20S TO NEAR 30 BELOW ZERO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 512 AM CST SAT JAN 18 2014
TAF SITES ARE IN THE THROWS OF AN ACCUMULATING SNOWFALL SYSTEM
THROUGH 15Z OR SO BEFORE CONDITIONS IMPROVE. THE RADAR BAND ON
RADAR IS SHIFTING SLIGHTLY EAST OF KRST AND DO EXPECT A SLIGHT
IMPROVEMENT TO 3/4SM TO 1SM BY TAF START UP. THE BAND IS HEADING
FOR KLSE AND SNOW WILL COME IN SUDDENLY WITH LIFR OCCURRING WITHIN AN
HOUR OF SNOWFALL START. KLSE VSBY SHOULD REMAIN AT 1/2-1SM UNTIL
MID-MORNING. BY 18Z VFR CONDITIONS ARE EXPECTED AT BOTH SITES AS
THE SYSTEM PULLS AWAY TO THE SOUTHEAST.
3-4 INCHES OF SNOW IS EXPECTED FROM THIS FAST MOVING SYSTEM.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032-
033-041-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
312 AM CST SAT JAN 18 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 312 AM CST SAT JAN 18 2014
MAIN FORECAST CONCERN THROUGH THE SHORT TERM CENTERED ON
ACCUMULATING SNOW TODAY.
WATER VAPOR/SURFACE ANALYSIS SHOW VIGOROUS LOW PRESSURE MOVING OUT
OF EASTERN ND SOUTHEAST INTO MN. RADAR AND SURFACE OBSERVATIONS
SHOWING AN EXPANSIVE NW-SE BAND OF LIGHT TO MODERATE SNOWFALL IN
ADVANCE OF THE LOW AND ATTENDANT WARM FRONTAL BOUNDARY EXTENDING
ACROSS MOST OF MN. INDICATION OF THE STRONG BAROCLINICITY ASSOCIATED
WITH THIS WAVE EVIDENCED BY TEMPERATURES RANGING FROM THE 30S ACROSS
THE DAKOTAS TO READINGS ONLY IN THE SINGLE DIGITS ABOVE AND BELOW
ZERO ACROSS THE NWS LA CROSSE FORECAST AREA.
MODELS ALL HONED INTO PROGGED TRACK OF THE LOW...TAKING IT SOUTHEAST
INTO SOUTH CENTRAL MN BY 12Z AND THEN INTO CENTRAL IL BY SUN 00Z.
DYNAMICS FAIRLY IMPRESSIVE WITH THE SYSTEM WITH STRONG ISENTROPIC
LIFT INDICATED BY RAP ON THE 275K SURFACE AND WEAK TO MODERATE
FRONTOGENETIC FORCING IN THE 1000-700MB LAYER. BUFKIT ALSO SHOWING
AROUND 17 MICROBARS OF LIFT THROUGH THE DENDRITIC GROWTH ZONE AT
KRST EARLY ON THIS MORNING. SNOW TO LIQUID RATIOS SHOULD BE FAIRLY
HIGH AS A RESULT...SOMEWHERE IN THE 16-18 TO 1 RANGE. GIVEN THIS AND
THE TRACK OF THE LOW...HEAVIEST SNOW BAND WILL SET UP ALONG AN AXIS
FROM DODGE CENTER AND ROCHESTER THROUGH DUBUQUE IA WHERE AROUND 4 TO
LOCALLY 5 INCHES IS EXPECTED THROUGH THE DAY. AS A RESULT...A WINTER
WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM THIS EVENING FOR ALL
OF SOUTHEAST MN/NORTHEAST IA..AND COUNTIES IN WI BORDERING THE
MISSISSIPPI AND WISCONSIN RIVERS. LOOKS LIKE MOST OF THE
ACCUMULATING SNOW MAY BE DONE/SHIFTED SOUTHEAST OF THE AREA BEFORE
6PM...BUT SOME DRIFTING OF THE SNOW WITH INCREASING NORTH WINDS ON
THE BACKSIDE OF THE LOW MAY STILL CAUSE SOME DRIVING
DIFFICULTIES...SO WILL LET IT UP THE THE DAYSHIFT TO ASSESS THE
STATUS OF THE ADVISORY HEADLINE GOING INTO THE AFTERNOON.
OTHERWISE...TEMPERATURES TODAY EXPECTED TO MODERATE INTO THE UPPER
TEENS TO MIDDLE 20S.
A RIDGE OF HIGH PRESSURE MOVES ACROSS THE AREA TONIGHT WITH WARM AIR
ADVECTION KICKING IN AFTER MIDNIGHT. LOOK FOR LOWS OCCURRING AROUND
MIDNIGHT IN THE UPPER SINGLE DIGITS/LOWER TEENS...THEN SLOWING
CLIMBING THROUGH THE TEENS AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT JAN 18 2014
MILDER DAY ON TAP FOR SUNDAY AS WARM AIR ADVECTION CONTINUES IN
ADVANCE OF A COLD FRONT MOVING SOUTHWARD OUT OF CANADA INTO NORTHERN
WI. LOOK FOR HIGHS TOPPING OFF IN THE MIDDLE 20S TO THE MIDDLE 30S.
THE COLD FRONT WILL CONTINUE MOVING SLOWLY SOUTHWARD ACROSS THE AREA
SUNDAY NIGHT AS A WEAK MID-LEVEL WAVE RIPPLES ALONG THE BAROCLINIC
ZONE IN PLACE. THIS WILL GIVE THE AREA A CHANCE FOR SOME VERY LIGHT
SNOWFALL.
THE COLD FRONT WILL ALSO MARK THE TRANSITION BACK TO COLDER THAN
NORMAL NORTHWEST FLOW GRIPPING THE REGION AGAIN. MODELS ALSO SHOW
VARIOUS EMBEDDED SHORTWAVE TROUGHS WITHIN THE FLOW FOR ON/OFF LIGHT
SNOW CHANCES THROUGH FRIDAY. CONFIDENCE ON TIMING THESE WAVES PRETTY
LOW AT THIS TIME WITH VARIOUS MODEL SOLUTIONS. OTHERWISE...LOOK FOR
HIGH TEMPERATURES GENERALLY IN THE SINGLE DIGITS AND TEENS ABOVE
ZERO WITH LOWS IN THE SINGLE DIGITS AND TEENS BELOW ZERO. APPEARS
WIND CHILL HEADLINES WILL LIKELY BE NEEDED MONDAY NIGHT/TUESDAY
MORNING AS WIND CHILL VALUES DIP INTO THE 20S TO NEAR 30 BELOW ZERO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1122 PM CST FRI JAN 17 2014
THE SURFACE LOW HAS MOVED INTO EASTERN NORTH DAKOTA THIS EVENING.
REGIONAL RADARS AND OBSERVATIONS INDICATE SNOW IS FALLING ON THE
EAST SIDE OF THE LOW ACROSS NORTHWEST MINNESOTA INTO EASTERN NORTH
DAKOTA WHERE IFR CONDITIONS ARE OCCURRING. THE 18.00Z NAM CAME IN
WITH A SUBTLE EASTWARD SHIFT WITH THE TRACK OF THE SURFACE LOW
PLACING KLSE BACK INTO THE THE HEAVIER SNOW AND THE 18.01Z HRRR IS
VERY SIMILAR. HAVE ESSENTIALLY MAINTAINED THE FORECAST FOR KRST
BRINGING THE SNOW IN AROUND 10Z WITH THE VISIBILITY QUICKLY GOING
DOWN TO LESS THAN A MILE WITH IFR CEILINGS. HAVE TRENDED DOWNWARD
WITH THE KLSE FORECAST SHOWING THE SNOW COMING IN AROUND 12Z WITH
THE VISIBILITY THEN GOING DOWN TO AROUND A MILE WITH MVFR
CEILINGS. STILL EXPECTING THE SNOW TO BE FAST MOVING WITH
IMPROVEMENTS BEGINNING LATE SATURDAY MORNING AND THE SNOW THEN
ENDING BY EARLY TO MID AFTERNOON. UNSURE ON WHAT TO DO WITH THE
CEILINGS BEHIND THE SNOW AS THE NAM BUFKIT SOUNDING WOULD SUGGEST
THE LOWER CLOUDS COULD SCATTER OUT. UPSTREAM OBSERVATIONS ACROSS
EASTERN SASKATCHEWAN SHOW THE LOWER CLOUDS STILL IN PLACE SO HAVE
OPTED TO STAY WITH A MVFR CEILING BEHIND THE SNOW AT KRST AND A
LOW VFR CEILING FOR KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032-
033-041-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1122 PM CST FRI JAN 17 2014
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 322 PM CST FRI JAN 17 2014
MAIN FORECAST CONCERNS THIS PACKAGE...SNOW CHANCES/AMOUNTS WITH FAST
MOVING SYSTEM LATER TONIGHT INTO EARLY SAT AFTERNOON.
DATA ANALYSIS AT 18Z HAD A COLD RIDGE OF HIGH PRESSURE SLOWLY
DRIFTING EAST ACROSS THE REGION...WITH THE LOWER CLOUDS/-SN SLOWLY
CLEARING FROM WEST TO EAST ACROSS WI/FAR EASTERN IA. SUNNY BUT COLD
CONDITIONS OVER MN/WESTERN WI/MUCH OF IA UNDER THE RIDGE. UPSTREAM
THE STRONGER PRESSURE FALLS AHEAD OF THE NEXT SYSTEM WERE ALREADY
CENTERED NEAR LK WINNIPEG. PER WV IMAGERY...SHORTWAVE FOR LATE
TONIGHT/SAT MORNING WAS QUICKLY MOVING SOUTH INTO NORTHERN SASKAT.
NO MAJOR PROBLEMS NOTED WITH 17.12Z MODEL INITIALIZATIONS. SOLUTIONS
ABOUT AS SIMILAR AS CAN BE EXPECTED FOR TONIGHT THRU SAT NIGHT AS
THE VIGOROUS SHORTWAVE INITIALIZED NORTH OF THE NW TERRITORIES/
ALBERTA LINE DIVES QUICKLY SOUTHEAST AND ACROSS THE REGION
TONIGHT/SAT. TREND OF THE MODEL SUITE CONTINUES STRONGER WITH THIS
FEATURE AS IT PASSES BUT AT LEAST THE TIMING HAS REMAINS RATHER
CONSISTENT. STILL SOME TRACK/SNOW SWATH DIFFERENCES AMONG THE MODELS
THAT WOULD HAVE IMPACTS ON THE SENSIBLE WEATHER CENTERED ON SAT
MORNING. CHECK AT 18Z SHOWED MODELS ALL LOOKING QUITE REASONABLE
WITH THE SHORTWAVE AS IT DROPS INTO NORTHERN SASKAT...VERY DIFFICULT
TO SAY IF ONE MODEL IS BETTER THAN THE OTHERS WITH THIS FEATURE
GIVEN THE OBLIQUE WV SATELLITE VIEWING ANGLE. ALL MODELS GOOD
WITH THE 12Z-18Z PRECIP OVER EASTERN WI AND ITS SLOW EXIT EAST
INTO EARLY THIS AFTERNOON. WITH NO ONE MODEL FAVORITE AND MINOR
DETAIL DIFFERENCES OVER NORTH-CENTRAL CAN HAVING IMPACTS ON THE
FCST THRU SAT...SIDED WITH THE MODEL/ENSEMBLE CONSENSUS. EVEN WITH
THE DIFFERENCE...SHORT TERM FCST CONFIDENCE REMAINS GENERALLY GOOD
THIS CYCLE.
FOR THE SHORT TERM...NORTHERN SASKAT SHORTWAVE AND ITS ATTENDANT SFC-
700MB LOW STILL ON TRACK TO SPREAD RATHER STRONG/DEEP LAYERED
FORCING/LIFT SOUTHEAST ACROSS THE FCST AREA LATE TONIGHT/SAT
MORNING. MODEL CONSENSUS FOR THE TRACK OF THE STRONGEST/DEEPEST LIFT
HAS CONTINUED TO SHIFT A BIT WEST...NOW LOOKING TO PASS ACROSS AREAS
MANLY WEST OF THE MS RIVER. HAVE TRENDED SNOW CHANCES/AMOUNTS
DOWNWARD ALONG/EAST OF I-94 FOR LATE TONIGHT/SAT. THE CONTINUED
STRONGER SOLUTIONS WITH THE SHORTWAVE AS IT PASSES BY PRODUCED
ANOTHER WESTWARD SHIFT OF THE SNOW BAND. THIS PUTS THE WINTER
WEATHER ADVISORY FOR COUNTIES FROM BUFFALO THRU LA CROSSE TO
RICHLAND IN QUESTION. APPEARS ONLY THE EXTREME WESTERN EDGE OF THESE
COUNTIES WITH A SHOT AT 3+ INCHES OF SNOW. GIVEN THE LINGERING
UNCERTAINTY WITH THE TRACK...EVEN A 20-30 MILE SHIFT EITHER WAY
WILL MEAN THE DIFFERENCE BETWEEN 1 TO 2 INCHES OF SNOW OR 3+
INCHES DOWN THE MS RIVER INTO THE BOSCOBEL/MUSCODA AREAS. LATEST
MODEL CONSENSUS HAS SHIFTED THE GREATER CHANCES OF 3 TO LOCALLY 5
INCHES OF SNOW INTO SOUTHEAST MN/NORTHEAST IA/FAR SOUTHWEST WI.
HOWEVER...WILL LEAVE THE WINTER WEATHER ADVISORY AS IS FOR
NOW...AS WOULD HATE TO UPDATE OUT OF A GOOD FCST IF A MORE EASTERN
TRACK ENDS UP MORE CORRECT OR SNOW-WATER RATIOS END UP HIGHER THAN
EXPECTED.
WITH FAST SPEED OF THE SYSTEM...TRENDED -SN CHANCES BY LATE SAT
AFTERNOON TO ONLY A 20-30 PERCENT CHANCE ACROSS THE SOUTHEAST
HALF OF THE FCST AREA. AS THE SFC-MID LEVEL TROUGH QUICKLY DEPARTS
SAT... WESTERLY LOWER LEVEL FLOW/WARM ADVECTION ALREADY SPREADS
ACROSS THE AREA SAT NIGHT. APPEARS LOWS SAT NIGHT WILL BE DURING
THE EVENING... WITH STEADY/SLOWLY RISING TEMPS OVERNIGHT.
GENERALLY USED THE MODEL/ ENSEMBLE CONSENSUS FOR LOWS/HIGHS
TONIGHT THRU SAT NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 322 PM CST FRI JAN 17 2014
MAIN FORECAST CONCERNS FOR SUNDAY THROUGH MONDAY
NIGHT...TEMPERATURE TREND THRU THE PERIOD...SMALL -SN CHANCE
MONDAY.
BETWEEN MODEL AND RUN-T0-RUN CONSISTENCY AMONG THE MODELS REMAINS
GOOD IN THE SUN THRU MON NIGHT PERIOD AS WEAK SHORTWAVE RIDGING
QUICKLY MOVES ACROSS THE AREA SUNDAY THEN HGTS FALL AS LONGWAVE
TROUGHING DEVELOPS OVER THE EASTERN CONUS. SUN-MON NIGHT CONTINUES
TO TREND TOWARD A QUIET PERIOD AS FAR AS -SN CHANCES GO...BUT TEMPS
STILL LOOKING TO BE A ROLLER-COASTER RIDE THIS PERIOD. FCST
CONFIDENCE IN THE SUN-MON NIGHT PERIOD IS GOOD THIS CYCLE.
LOW LEVEL WARM ADVECTION INTO MID-DAY SUNDAY SENDS 925MB TEMPS INTO
THE -4C TO +4C RANGE THRU THE MORNING HOURS. THIS WARM AIR OVER THE
AREA IS SHORT LIVED GIVEN THE CONTINUED RAPID PROGRESSION OF THE
FLOW. ALL MODELS HAVE -20C OR COLDER 925MB AIR POOLED OVER ONT/LK
SUPERIOR AT 18Z. THIS WITH THE LOW LEVEL FLOW SWINGING TO THE
NORTHWEST AND NORTH BEHIND A SFC-850MB TROUGH/FRONT BEING PUSHED
SOUTH ACROSS THE AREA SUN AFTERNOON/NIGHT. BY 12Z MONDAY...925MB
TEMPS ACROSS THE AREA FALL INTO THE -10C TO -20C RANGE...AND ARE IN
THE -20C TO -22C RANGE AT 12Z TUE. AFTER ABOVE NORMAL HIGHS ON
SUNDAY...WITH LIGHT WINDS AND SOME SUNSHINE...TEMPS HEAD DOWN AND
BACK TO WELL BELOW NORMAL BY MON/MON NIGHT. NORTHWEST GRADIENT WINDS
OF 6 TO 12 MPH EXPECTED MON NIGHT...AS TEMPS FALL INTO THE -6F TO -
12F RANGE. STILL APPEARS A WIND CHILL ADVISORY WILL BE NEEDED FOR
LATE MON NIGHT/TUE MORNING. SOME 925-700MB MOISTURE ACCOMPANIES THE
MODEST SFC-700MB TROUGH/FRONT SOUTH ACROSS THE AREA SUN NIGHT...WITH
COLD CYCLONIC FLOW AND THE MID LEVEL TROUGH MOVING ACROSS THE AREA
MONDAY. ADDED A SMALL -SN/FLURRY MENTION TO SUN NIGHT GRIDS AND SCT
FLURRIES MENTION TO MON GRIDS. FAVORED WARMER OF GUIDANCE HIGHS
FOR SUN...TRENDING TOWARD COLDER OF GUIDANCE HIGHS/LOWS BY MON/MON
NIGHT.
FOR TUESDAY THROUGH FRIDAY.../DAYS 4 TO 7/...
RATHER GOOD BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY AMONG 17.00Z
AND 17.12Z MEDIUM RANGE MODEL RUNS FOR COLD LONGWAVE TROUGHING TO
SET UP SHOP OVER EASTERN NOAM FOR THE TUE-FRI PERIOD. SOME
DIFFERENCES IN THE DAY-TO-DAY SHORTWAVES THRU WHAT WILL BE NORTHWEST
FLOW ALOFT OVER THE UPPER MIDWEST...BUT THIS EXPECTED IN THE DAY 4-7
TIME-FRAME. FCST CONFIDENCE HIGH THAT TEMPS WILL BE BELOW TO WELL
BELOW NORMAL TUE-FRI...BUT CONFIDENCE AVERAGE AT BEST IN ANY OF THE
DAY-TO-DAY -SN CHANCES.
850MB TEMPS LOOKING TO BE SOME 1 TO 2 STANDARD DEVIATIONS BELOW
NORMAL MUCH OF TUE-FRI UNDER THIS COLD-CORE TROUGH. 925MB TEMPS
PROGGED TO REMAIN IN THE -18C TO -22C RANGE MUCH OF THE TUE THRU
THU PERIOD. MAXES/MINS THIS PERIOD LOOKING TO BE AROUND 20F BELOW
NORMAL. A SIGNAL FOR A QUICK SHOT OF LOWER LEVEL WARM ADVECTION TO
SPREAD ACROSS THE AREA TUE NIGHT/WED AS A SFC TO MID LEVEL TROUGH
SWINGS BY AND BRINGS A RE-ENFORCING SHOT OF COLD AIR TO THE
REGION. SMALL CONSENSUS -SN CHANCES FOR TUE NIGHT/WED LOOK GOOD
FOR NOW. SOME CONSISTENCY AMONG GFS/ECMWF FOR A STRONGER ROUND OF
LOW LEVEL WARM ADVECTION TO SPREAD ACROSS THE AREA LATE IN THE
WEEK...FOR SOME MODERATION OF TEMPS INTO FRIDAY. WOULD EXPECT THIS
FORCING TO ALSO BRING WITH IT A -SN CHANCE BUT MODELS AT ODDS ON
THE TIMING OF LOWER LEVEL FEATURES BY THU/FRI. SMALL -SN CHANCE
MUCH OF THU THRU FRI REASONABLE FOR NOW. GIVEN SOME UNCERTAINTIES
CONCERNING CLOUD COVER FOR TUE-FRI...USED THE MODEL/ENSEMBLE
CONSENSUS HIGHS/LOW THRU THE DAY 4-7 PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1122 PM CST FRI JAN 17 2014
THE SURFACE LOW HAS MOVED INTO EASTERN NORTH DAKOTA THIS EVENING.
REGIONAL RADARS AND OBSERVATIONS INDICATE SNOW IS FALLING ON THE
EAST SIDE OF THE LOW ACROSS NORTHWEST MINNESOTA INTO EASTERN NORTH
DAKOTA WHERE IFR CONDITIONS ARE OCCURRING. THE 18.00Z NAM CAME IN
WITH A SUBTLE EASTWARD SHIFT WITH THE TRACK OF THE SURFACE LOW
PLACING KLSE BACK INTO THE THE HEAVIER SNOW AND THE 18.01Z HRRR IS
VERY SIMILAR. HAVE ESSENTIALLY MAINTAINED THE FORECAST FOR KRST
BRINGING THE SNOW IN AROUND 10Z WITH THE VISIBILITY QUICKLY GOING
DOWN TO LESS THAN A MILE WITH IFR CEILINGS. HAVE TRENDED DOWNWARD
WITH THE KLSE FORECAST SHOWING THE SNOW COMING IN AROUND 12Z WITH
THE VISIBILITY THEN GOING DOWN TO AROUND A MILE WITH MVFR
CEILINGS. STILL EXPECTING THE SNOW TO BE FAST MOVING WITH
IMPROVEMENTS BEGINNING LATE SATURDAY MORNING AND THE SNOW THEN
ENDING BY EARLY TO MID AFTERNOON. UNSURE ON WHAT TO DO WITH THE
CEILINGS BEHIND THE SNOW AS THE NAM BUFKIT SOUNDING WOULD SUGGEST
THE LOWER CLOUDS COULD SCATTER OUT. UPSTREAM OBSERVATIONS ACROSS
EASTERN SASKATCHEWAN SHOW THE LOWER CLOUDS STILL IN PLACE SO HAVE
OPTED TO STAY WITH A MVFR CEILING BEHIND THE SNOW AT KRST AND A
LOW VFR CEILING FOR KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST SATURDAY FOR
WIZ032-033-041-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST SATURDAY FOR
MNZ079-086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM CST SATURDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1150 PM EST SUN JAN 19 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM EST SUN JAN 19 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT NW FLOW
ALF OVER THE GREAT LKS BTWN UPR TROF OVER EASTERN NAMERICA AND A RDG
NEAR THE PACIFIC COAST. COLD FNT ASSOCIATED WITH STRONG DISTURBANCE/
SFC LO PRES MOVING INTO WRN QUEBEC IS IN THE PROCESS OF PUSHING N-E
THRU UPR MI EARLY THIS AFTN ACCOMPANIED BY SOME GENERALLY LGT SN
MAINLY NEAR LK SUP. MUCH COLDER AIR WITH 12Z H85 TEMPS AS LO AS -27C
AT YPL IS FOLLOWING THIS FNT...AND SFC TEMPS ARE IN THE PROCESS OF
FALLING OVER THE NRN TIER. DESPITE THE INFLUX OF MUCH COLDER AIR...
THE COMBINATION OF DNVA AHEAD OF AN APRCHG SHRTWV RDG/LOWERING INVRN
BASE TOWARD 3K FT PER SHORT TERM FCST SDNGS AND ADVECTION OF DRIER
LLVL AIR OSBVD IN ONTARIO IS TENDING TO HAMPER THE INTENSITY OF LES
FOLLOWING THE FROPA. IN FACT...VSBL STLT IMAGERY IS SHOWING QUITE A
BIT OF CLRG OVER THE N HALF OF LK SUP. THERE IS ANOTHER SHRTWV NEAR
LK WINNIPEG THAT IS DIVING ESEWD TOWARD THE CWA. STLT IMAGERY DOES
SHOW SOME ENHANCED CLD IN THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF
THIS FEATURE...BUT THE LLVL DRYING IN THE NNE FLOW TO THE S OF SFC
ARCTIC HI PRES CENTERED OVER NRN MANITOBA IS LIMITING SN COVERAGE/
INTENSITY. YET ANOTHER CLIPPER TYPE SHRTWV OVER ALBERTA IS MOVING
SEWD.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE LES/SN AMOUNTS/GOING
HEADLINES AND IMPACT OF CLIPPER SHRTWVS THAT WL BE DIVING SEWD THRU
THE UPR LKS.
TNGT...SFC COLD FNT NOW DROPPING SWD THRU UPR MI WL CLEAR MENOMINEE
BY 00Z MON. INFLUX OF COLD AIR IN THE LLVL NLY FLOW BEHIND THIS
FROPA THAT IS FCST TO DROP H85 TEMPS TO ARND -23C OR -24C OVER THE
NRN TIER BY 12Z MON WL GENERATE LES IN THE FAVORED SN BELTS.
ALTHOUGH LLVL DRYING/LO INVRN BASE WL HAVE A NEGATIVE IMPACT ON THE
INTENSITY OF THE SHSN IN THE SHORT TERM...ARRIVAL OF DPVA/DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH PAIR OF UPSTREAM CLIPPER SHRTWVS IS
FCST TO SLOWLY RAISE FCST INVRN BASE AND BRING ABOUT SOME DEEPER
MOISTENING. THE RESULT SHOULD BE AN INCRS IN LES INTENSITY
ESPECIALLY E OF MQT...WHERE LONGER FETCH OVER ICE FREE WATER AND
SHARPER LLVL CNVGC OVER ALGER/NRN SCHOOLCRAFT COUNTIES ON WRN FLANK
OF LAND BREEZE FLOW OFF ONTARIO WL TEND TO PLAY A POSITIVE ROLE
DESPITE SOME SLOWLY SHIFTING LLVL WINDS ACCOMPANYING PASSAGE OF UPR
DISTURBANCE. GOING LES ADVY FOR THE ERN CWA SEEMS APPROPIATE. AWAY
FM MOISTENING ASSOCIATED WITH LK SUP...DYNAMIC SUPPORT FM CLIPPER
SHRTWV WL PRODUCE NOTHING MORE THAN ISOLD-SCT LGT SHSN WITH LLVL
DRYING OFFSETTING THE ACCOMPANYING UPWARD MOTION. NLY FLOW OFF LK
SUP/ABUNDANT CLD COVER WL TEND TO MODERATE MIN TEMPS DESPITE THE
ARRIVAL OF THE COLDER AIR.
MON...CLIPPER NOW OVER ALBERTA/ACCOMPANYING DPVA AND DEEP LYR
QVECTOR CNVGC IS PROGGED TO SLIDE SEWD ACRS THE UPR MIDWEST/UPR LKS
IN THE MRNG. THIS DISTURBANCE SHOULD MAINTAIN HIER INVRN BASE AND
PERSISTENT LES NEAR LK SUP AS H85 TEMPS FALL TO ARND -26C IN SLOWLY
SHIFTING LLVL NLY FLOW. BUT THE DIMINISHING DGZ DEPTH ACCOMPANYING
INFLUX OF EVEN COLDER AIR AS WELL AS SLOWLY SHIFTING LLVL WINDS WL
TEND TO LIMIT SN TOTALS. BUT WL CONTINUE CATEGORICAL POPS FOR LES IN
THE FAVORED SN BELTS E OF MQT. ALTHOUGH THERE COULD BE SOME FREQUENT
SHSN EARLY NEAR IWD CLOSER TO THE TRACK OF THIS SECOND CLIPPER...
WENT WITH NO MORE THAN LIKELY POPS OVER THE WRN SN BELTS CONSIDERING
WEAKER LLVL CNVGC/MORE ICE COVER. WITH THE ARRIVAL OF COLDER AIR AND
ABUNDANT CLD COVER IN GENERAL N FLOW OFF LK SUP...EXPECT LTL DIURNAL
TEMP RECOVERY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM EST SUN JAN 19 2014
MODELS ARE IN GOOD AGREEMENT THROUGH MID WEEK WITH DETAILS ON LES
AND A CLIPPER SYSTEM MOVING THROUGH ON WED.
STARTING 00Z TUE...THE CWA WILL BE BENEATH A BROAD UPPER
TROUGH...WITH A WEAK SHORTWAVE JUST N OF LAKE SUPERIOR. 850MB TEMPS
WILL START OUT AOB -25C. LOW LEVEL WINDS WILL BE OUT OF THE NNW AS
THE CWA IS BETWEEN A SFC TROUGH OVER THE ERN SEABOARD AND A 1040MB
HIGH CENTERED OVER ND. A TROUGH WILL BE DRAPED FROM THE SSE INTO ERN
LAKE SUPERIOR...PROMOTING CYCLONIC FLOW THERE...WHILE FLOW OVER FAR
WRN LAKE SUPERIOR WILL BE SLIGHTLY ANTICYCLONIC. LES WILL BE ONGOING
IN ALL NNW WIND SNOWBELT...BUT THE MOST INTENSE SNOW WILL BE
DOWNWIND OF ERN LAKE SUPERIOR AS CONDITIONS THERE WILL BE MORE
FAVORABLE FOR MODERATE TO LOCALLY HEAVY LES /INCLUDING INVERSION
TOPS AROUND 7KFT/. NOT MUCH CHANGES THROUGH THE REST OF MON
NIGHT...EXCEPT THAT THE SFC HIGH WILL SLIDE TO FAR SW MN...MAKING
FOR EVEN LESS FAVORABLE FLOW AND SUBSIDENCE OVER WRN LAKE
SUPERIOR...WHILE THE TROUGH OVER ERN LAKE SUPERIOR REMAINS. THE MOST
UNCERTAINTY WITH LOCAL EFFECTS IS WITH ICE COVERAGE OVER WRN LAKE
SUPERIOR THAT MAY CLOSE DOWN PORTIONS OF THE LAKE TO LES. THERE WAS
GOOD ICE COVERAGE OVER THE W WHEN LOOKING AT SATELLITE IMAGERY
YESTERDAY...BUT WITH STRONG SW WINDS LAST NIGHT TURNING MORE NWLY
TODAY...NOT SURE ABOUT THE COVERAGE AND LOCATION OF THAT ICE INTO
THE FUTURE. THE NIGHT SHIFT LAST NIGHT PUT UP AN ADVISORY FOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES...WHICH STILL LOOKS GOOD
THROUGH MON NIGHT.
THEN FOR TUE...THE SFC HIGH CONTINUES TO MOVE SE AS THE SFC TROUGH
OVER THE ERN LAKE DIMINISHES. FLOW BECOME VERY ANTICYCLONIC OVER ALL
BUT EXTREME ERN LAKE SUPERIOR /WHERE IT WILL BE NEUTRAL/ BY 00Z WED.
850MB TEMPS ALSO INCREASE TO AROUND -20C UNDER THE SFC RIDGE TUE.
SHOULD SEE LES DIMINISH THROUGH THE DAY...ESPECIALLY OVER THE W AND
CENTRAL. EVEN WITH CONDITIONS BEING UNFAVORABLE FOR SIGNIFICANT LES
OVER CENTRAL AND WRN UPPER MI...AREAS DOWNWIND OF LAKE SUPERIOR
SHOULD CONTINUE TO SEE SNOW...WHICH WOULD MAINLY BE AREAS N OFF THE
PORCUPINE MOUNTAINS OVER THE NWRN CWA. EXTENDED PREVIOUSLY MENTIONED
HEADLINES THROUGH TUESDAY AS THE LAKE TROUGHING SHOULD STICK AROUND
OVER ERN LAKE SUPERIOR...HELPING TO CONTINUE LES THROUGH MUCH OF THE
DAY. TUE LOOKS TO BE THE COLDEST DAY OF THE WEEK WITH HIGHS IN THE
SINGLE DIGITS ABOVE ZERO IN MOST LOCATIONS.
A CLIPPER SYSTEM BEGINS TO IMPACT WEATHER OVER THE CWA STARTING TUE
NIGHT AS THE SHORTWAVE MOVES TO N OF LAKE SUPERIOR IN ONTARIO BY 12Z
WED...BRINGING A BROAD...WEAK SFC LOW TO THE AREA. THIS LOW LOOKS TO
BE ENHANCED BY LAKE AGGREGATE AS A MESO LOW MAY FORM OVER LAKE
SUPERIOR...BUT TO WHAT MAGNITUDE AND EXACTLY WHERE IS UNCERTAIN. THE
12Z/19 NAM...00Z/19 GLOBAL GEM AND TO SOME EXTENT THE 00Z/19 ECMWF
FAVOR THE MESO LOW TO MOVE OVER E CENTRAL LAKE SUPERIOR...MOVING
INTO UPPER MI SOMEWHERE E OF MARQUETTE WED EVENING. THIS PATH IS
TYPICALLY WITH THIS TYPE OF PATTERN...BUT THE EXACTLY WHERE THAT LOW
MOVES WILL DETERMINE WHERE THE STRONGEST SNOW AND WIND WILL FOCUS.
THIS COULD BE QUITE AN INTERESTING EVENT OVER A SHORT PERIOD OF TIME
AS THE MESO LOW WILL VERY QUICKLY SHIFT SE AS IT MOVES OFF OF LAKE
SUPERIOR...WHILE AT THE SAME TIME A 1050MB HIGH MOVES ACROSS THE
DAKOTAS INTO THE CENTRAL PLAINS...SHUNTING A 1030MB SFC RIDGE INTO
THE CWA LATE WED NIGHT INTO THU. MOST OF THE CWA WILL SEE GUSTY
WINDS AS A RESULT OF THE PRESSURE GRADIENT AND PRESSURE RISE...BUT
THE AREA OF MOST CONCERN IS ON THE W SIDE OF THE TRACK OF THE
POSSIBLE MESO LOW...WHERE BLIZZARD LIKE CONDITIONS MAY BE POSSIBLE.
WITH LOW LEVEL WINDS OUT OF THE NNE FOR ABOUT 6 HOURS ALONG AND
BEHIND THE MESO LOW AND FROM JUST AHEAD TO JUST BEHIND THE
SHORTWAVE...NCENTRAL UPPER MI WOULD BE FAVORED FOR UPSLOPE AND LAKE
ENHANCEMENT THAT MAY MAKE FOR VERY TREACHEROUS CONDITIONS SOMEWHERE
IN THE LATE WED AFTERNOON THROUGH WED EVENING TIME FRAME.
AGAIN...THESE ARE PRETTY LOCALIZED CONDITIONS WHICH WILL BE
DIFFICULT TO EXACTLY PREDICT EVENT A DAY OUT...BUT THE CHANCE OF
THIS HAPPENING SOMEWHERE ACROSS NCENTRAL UPPER MI IS PRETTY GOOD
GIVEN THE OVERALL PATTERN. OUTSIDE OF THE IMMEDIATE AREA AFFECTED BY
THE MESO LOW...THE REST OF NWRN UPPER MI LOOKS FAVORED FOR A GOOD
BURST OF SNOW AS THE SHORTWAVE PASSES.
EXPECT LES WED NIGHT AS LOW LEVEL WINDS SHIFT FROM NLY TO NWLY WITH
-25C 850MB TEMPS...BUT WITH THE SFC RIDGE PASSING OVERHEAD ON
THU...THE LES SHOULD QUICKLY WEAKEN THU MORNING/EARLY AFTERNOON.
HOWEVER...BY LATER THU...WINDS WILL BECOME MORE CYCLONIC AHEAD OF
ANOTHER CLIPPER THAT WILL STAY MAINLY NE OF THE CWA. THE MORE
FAVORABLE CURVATURE TO THE FLOW WILL FAVORED THE KEWEENAW FOR LES AS
STRONG WINDS WILL BE OUT OF THE WSW THROUGH 06Z FRI...VEERING OUT OF
THE WNW BEHIND THE CLIPPER BY 18Z FRI. 850MB TEMPS LATE THU THROUGH
FRI WILL BE IN THE -15C TO -20C RANGE...WHICH WILL PUT MORE OF THE
THERMAL PROFILE IN THE DGZ...BUT INVERSION HEIGHTS LOOK TO ONLY BE
4-5KFT.
UNCERTAINTY INCREASES CONSIDERABLY FOR THE WEEKEND AS MODELS HAVE
NOT SHOWN GOOD CONTINUITY WITH THE PLACEMENT OF FEATURES THIS FAR
OUT. ONE TREND THAT CAN BE NOTED IS THAT THE COLDER AIR /850MB TEMPS
BELOW -30C/ SHOWN IN PREVIOUS SEVERAL MODEL RUNS MOVING OVER THE CWA
IS NOW BEING SHOWS AS MORE OF A GLANCING BLOW...WITH THE COLDEST AIR
TO THE NE. THIS COULD CHANGE...BUT AT LEAST IT IS A NOTABLE TREND
FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1150 PM EST SUN JAN 19 2014
A COLD NORTHERLY FLOW OF ARCTIC AIR ACROSS LAKE SUPERIOR WILL BRING
LAKE EFFECT -SHSN TO KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
HOWEVER...A FEED OF LOW-LEVEL DRY AIR ASSOCIATED WITH COLD HI PRES
OVER SCENTRAL CANADA WILL TEND TO LIMIT THE INTENSITY OF THE SNOW.
ALTHOUGH LAKE EFFECT TYPICALLY BRINGS VARIABLE CONDITIONS...
SOMETIMES HIGHLY VARIABLE...EXPECT MVFR CONDITIONS TO BE THE GENERAL
PREVAILING CONDITION AT ALL TERMINALS DURING THIS FCST PERIOD. THERE
WILL PROBABLY BE SOME PERIODS OF VFR CONDITIONS...AND THE BEST CHC
FOR IFR CONDITIONS WILL BE AT KIWD THIS MORNING WHEN A PASSING
DISTURBANCE IN THE PRESENCE OF A FAVORABLE NNE FLOW AND DEEPER
MOISTURE MAY ENHANCE THE SHSN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EST SUN JAN 19 2014
EXPECT N TO NW WINDS UP TO 25 TO 30 KTS TONIGHT AND MON E OF ARCTIC
HI PRES IN SCENTRAL CANADA. WITH A VERY COLD AIRMASS MOVING INTO THE
UPPER LAKES...THE RESULTING WAVE ACTION WILL CAUSE WIDESPREAD HEAVY
FREEZING SPRAY.
HEAVY FREEZING SPRAY WILL CONTINUE ACROSS ALL OF LAKE SUPERIOR
THROUGH AT LEAST TUESDAY IF NOT LONGER AS AREA IS ENTRENCHED IN COLD
AIR. NEXT GALE EVENTS LOOK TO BE ACROSS CENTRAL AND EASTERN LAKE
SUPERIOR LATE WEDNESDAY INTO WEDNESDAY NIGHT AND ANOTHER EVENT FOR
THURSDAY NIGHT ACROSS THE SAME AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST TUESDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR LSZ244-
245-248>251-264>267.
HEAVY FREEZING SPRAY WARNING FROM 7 AM MONDAY TO 7 AM EST
TUESDAY FOR LSZ243-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1042 PM MST Sun Jan 19 2014
Update to Aviation
.UPDATE...
Tonight...A weak disturbance is moving through the northwest flow
aloft and an associated cold front moved through the northern zones
and pushed into the central. This front is dry and the main effect
will be cooler temperatures tonight and tomorrow. Updated to lower
low temps for tonight across the northern and southern zones. Also
freshened pops and wx. Zelzer
&&
.AVIATION...
UPDATED 542Z.
VFR conditions will prevail at all sites through the TAF period. Mid
level clouds will taper off by 10Z. Mercer
&&
.PREV DISCUSSION...
/ISSUED 445 PM MST Sun Jan 19 2014/
Tonight through Tuesday...Overall pattern remains unchanged with a
strong upper ridge over the west coast and dry northwest flow
aloft. Models move a weak short wave embedded within the northwest
flow aloft through the area late this evening. Surface winds will
shift to the north for a few hours. The RUC and the European
models develop light qpf near the Little Belts as a result of this
weak upslope flow. HRRR analysis also develops qpf in this area
for a few hours late this evening. Have gone with low pops to
support this possibility. The surface gradient is not as tight on
Monday allowing for lighter winds. Monday and Tuesday will
continue dry with a northerly flow aloft. Temperatures will remain
above seasonal averages.
Tuesday night through Sunday...The main change in the extended
period was to increase the chances for rain/snow Wednesday into
Wednesday night...as both the EC/GFS continue to show an upper
level disturbance moving southward through the region. There looks
to be a bit more moisture with this disturbance...thus pops have
been increased...especially in the mountains around Kings Hill.
Snow accumulations still look to be on the low side...with most
lower elevation locations only seeing around 1 inch of
snowfall...and about 2 to 3 inches in the mountains. After this
disturbance moves through little to no precipitation is expected
from Thursday through Sunday. Temperatures will cool a bit
Wednesday as the disturbance moves through the region...with high
temperatures likely in the morning and then falling in the
afternoon. It will be cold Wednesday night as skies clear out a
bit...and with the possible fresh snow cover...temperatures will
fall rather quickly early Thursday morning. Otherwise...expect
afternoon temperatures to generally be about 5 to 10 degrees above
normal starting as early as Thursday afternoon and then continuing
into next weekend. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 24 46 29 51 / 0 0 0 0
CTB 19 44 24 47 / 0 0 0 0
HLN 23 43 24 46 / 0 0 0 0
BZN 20 39 19 42 / 0 0 0 0
WEY 7 32 8 33 / 0 0 0 0
DLN 22 41 23 45 / 0 0 0 0
HVR 20 35 20 40 / 0 0 0 0
LWT 23 39 25 44 / 0 0 0 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 11 AM MST Monday Liberty.
&&
$$
weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/US.NationalWeatherService.GreatFalls.gov
AREA FORECAST DISCUSSION
NWS HASTINGS NE
104 AM CST MON JAN 20 2014
.UPDATE...
ISSUED AT 100 AM CST MON JAN 20 2014
DECREASED DEWPOINTS FOR MUCH OF THE OVERNIGHT...FOLLOWING CLOSER
TO THE LATEST RAP NUMERICAL MODEL. EVERYTHING ELSE IS PRETTY MUCH
ON TRACK.
UPDATE ISSUED AT 943 PM CST SUN JAN 19 2014
NORTHWEST WINDS WILL INCREASE ON MONDAY FOLLOWING THE PASSAGE OF A
COLD FRONTAL BOUNDARY. FORECAST SOUNDINGS INDICATE DEEP MIXING IN
THE AFTERNOON...NEAR H75 WITH WINDS AT THE TOP OF THE LAYER 45 TO
55KTS AND THREE HOUR SFC PRESSURE RISES AVERAGE 3 TO 9 MB MONDAY
AFTERNOON AND EVENING. WENT AHEAD AND ISSUED A WIND ADVISORY FOR
LOCATIONS ALONG/NORTH OF HIGHWAY 6 IN NEBRASKA UNTIL 6 PM. HAVE
CONCERNS THAT WINDS WILL REMAIN STRONGER INTO THE EVENING BEYOND
THE 6 PM TIME FRAME DUE TO THE TIGHT GRADIENT/STRONG PRESSURE RISES
AND THIS WILL NEED TO BE MONITORED.
UPDATE ISSUED AT 602 PM CST SUN JAN 19 2014
THE RED FLAG WARNING WAS ALLOWED TO EXPIRE AT 6 PM AS WIND SPEEDS
WILL DIMINISH THIS EVENING AND RELATIVE HUMIDITIES WILL INCREASE
AS TEMPERATURES COOL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 353 PM CST SUN JAN 19 2014
MAIN FORECAST CONCERNS WILL BE TEMPERATURES AND WINDS.
SATELLITE AND OBSERVATIONS SHOW A FEW CIRRUS CLOUDS MOVING
THROUGH THE FORECAST AREA THIS AFTERNOON. CURRENT OBSERVATIONS
HAVE RELATIVE HUMIDITY DOWN AROUND 15 TO 20 PERCENT THIS
AFTERNOON...BUT THE WINDS HAVE BEEN UNDER 20 MPH FOR THE MOST
PART.
A WEAK COLD FRONT HAS BEEN MOVING THROUGH THE FORECAST AREA
THIS AFTERNOON. WINDS TURN SLIGHTLY TO THE NORTHWEST BEHIND THE
TROUGH. THE FRONT SHOULD BE THROUGH THE FORECAST AREA EARLY THIS
EVENING. TEMPERATURES ALOFT COOL DURING THE NIGHT. STILL EXPECT
THAT THE LOWS TONIGHT WILL BE IN THE 20S.
THE NEXT CONCERN WILL BE WITH THE WINDS FOR TOMORROW. THE
PRESSURE GRADIENT TIGHTENS DURING THE AFTERNOON AND EXPECT BREEZY
CONDITIONS ACROSS THE ENTIRE AREA. THE STRONGEST WINDS WILL BE IN
THE NORTHERN PART OF THE FORECAST AREA. CURRENT WIND SPEEDS THAT
ARE IN THE GRIDS ARE JUST AT WIND ADVISORY CRITERIA. WILL WAIT AT
THIS TIME FOR WIND ADVISORY THAT LOOKS LIKE IT WILL BE POSSIBLE IN
THE NORTH.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 353 PM CST SUN JAN 19 2014
DRY WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE EXTENDED
FORECAST PERIOD. THERE COULD BE A PRETTY GOOD TEMPERATURE CONTRAST
FROM NORTHEAST TO SOUTHWEST ACROSS THE FORECAST AREA ON TUESDAY
AND WEDNESDAY RANGING FROM BELOW NORMAL HIGH TEMPERATURES IN THE
NORTHEAST AND ABOVE NORMAL HIGHS IN THE SOUTHWEST. THURSDAY IS A
BITTERLY COLD DAY EVERYWHERE...WHILE TEMPERATURES SHOULD QUICKLY
WARM TO BACK ABOVE NORMAL BY FRIDAY AND SATURDAY.
TUESDAY...A 1040MB HIGH WILL SLIDE SOUTHEAST OUT OF THE DAKOTAS
AND INTO IOWA ON TUESDAY BRINGING WITH IT A BRUSH OF COLD AIR WITH
THE WORST OF THE COLD AIR SLIDING EAST OF OUR FORECAST AREA. MOST
AREAS WILL PICK UP A SOUTHERLY OR EVEN WESTERLY SFC WIND COMPONENT
DURING THE DAY ON TUESDAY AS THE SYSTEM SLIDES TO OUR EAST...WHICH
WILL ALLOW TEMPERATURES TO START TO MODERATE FROM WEST TO EAST AND
KEEP THE COLD AIR FROM WORKING VERY FAR TO THE WEST.
THEREFORE...COULD SEE A NICE TEMPERATURE GRADIENT TUESDAY
AFTERNOON WITH HIGHS RANGING FROM AROUND 30 EAST TO THE MID 40S
WEST.
WEDNESDAY...THIS WILL BE A VERY DIFFICULT TEMPERATURE FORECAST AS
A STRONG COLD FRONT WILL TRACK THROUGH THE AREA AND TIMING OF THIS
FRONT WILL HAVE A BIG IMPACT ON TEMPERATURES. WILL KEEP NORTHEAST
ZONES AROUND 30 FOR HIGHS GIVEN THE EXPECTATION OF AN EARLIER
FRONTAL PASSAGE WHILE GOING WITH THE LOWER 40S ACROSS OUR KANSAS
AND SOUTHWESTERN NEBRASKA ZONES WHERE THE FRONT WILL ONLY REACH
LATER IN THE DAY. WE COULD ALSO SEE SOME FLURRIES OR VERY LIGHT
SNOW WITH THE FRONT LATE WEDNESDAY AFTERNOON OR WEDNESDAY
EVENING...BUT UNCERTAINTY IS TOO HIGH TO MENTION IT IN THE
FORECAST AT THIS POINT IN TIME.
THURSDAY...SHOULD CERTAINLY BE THE COLDEST DAY OF THE WEEK AS THE
COLD AIR SETTLES IN BEHIND THE WEDNESDAY/WEDNESDAY NIGHT COLD FRONT.
HIGHS ARE ONLY EXPECTED TO REACH INTO THE TEENS NORTHEAST TO THE
LOWER 20S SOUTHWEST. A 1045 SFC HIGH WILL SLIDE RIGHT OVER US ON
SUNDAY...THIS IS SOME PRETTY COLD AIR.
FRIDAY THROUGH SUNDAY...DRY AND WARM WITH UPPER RIDGING ACROSS THE
WESTERN CONUS. NO PRECIPITATION IS EXPECTED AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1153 PM CST SUN JAN 19 2014
WIND WILL BE THE BIG CONCERN WITH INCREASED MIXING TO 750 MB.
&&
.FIRE WEATHER...
ISSUED AT 353 PM CST SUN JAN 19 2014
RELATIVE HUMIDITY HAS DROPPED TO 15 TO 20 PERCENT FOR THIS
AFTERNOON AND WINDS WINDS THAT HAVE PICKED UP TO 20 TO 30 MPH IN
THE NORTHERN PART OF THE FORECAST AREA...HAVE ISSUED A RED FLAG
WARNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM CST THIS EVENING
FOR NEZ039>041-046>049-060>064-072>077.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...JCB
LONG TERM...JJW
AVIATION...HEINLEIN
FIRE WEATHER...JCB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
451 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CONTINUE TO PRODUCE PERIODS OF SNOW
SHOWERS AND POSSIBLE SNOW SQUALLS AS IT MOVES SOUTHEASTWARD
ACROSS THE NORTH COUNTRY TODAY. BEHIND THE FRONT...A RETURN OF
MUCH COLDER AND DRIER CONDITIONS IS EXPECTED FOR THE UPCOMING
WEEK. HIGH TEMPERATURES EACH DAY TUESDAY THROUGH THURSDAY WILL BE
ONLY IN THE SINGLE DIGITS ABOVE ZERO...AND LOWS WILL BE IN THE
SINGLE DIGITS TO TEENS BELOW. MILDER TEMPERATURES RETURN FOR
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 415 AM EST MONDAY...ARCTIC FRONT CONTINUES TO MAKE ITS WAY
THROUGH THE BTV CWA THIS MORNING WITH WIDESPREAD SNOW SHOWERS
ACROSS THE MAJORITY OF CENTRAL AND NORTHERN AREAS AT THIS EARLY
HOUR. TRENDS CONTINUE FOR A SLOWER PROGRESSION OF THE FRONT
SOUTHEASTWARD AS A SERIES OF SHORTWAVE TROUGHS NOTED ON LATEST WV
IMAGERY AND RUC PVA ANALYSIS TRAVERSE THE AREA...SO HAVE
CONTINUED TO MENTION LIKELY POPS ACROSS NORTHERN AREAS THROUGH
MID-MORNING...AND ACROSS SOUTHERN AREAS THROUGH THE AFTERNOON.
LOOKING AT UPSTREAM SURFACE OBS...NOT A LOT OF QPF ASSOCIATED WITH
THE FRONT AND EXPECT OVERALL SNOW ACCUMULATIONS TO BE GENERALLY A
DUSTING TO 2"...BUT LOCALIZED SQUALLS REMAIN POSSIBLE WHICH COULD
CRANK OUT AN ADDITIONAL 1-2". TEMPS WILL BE VERY TRICKY TODAY
OWING TO DIFFICULTY TIMING THE PASSAGE OF THE FRONT...BUT AREAS
NORTH OF RUTLAND/WINDSOR COUNTIES WILL LIKELY REALIZE MAX TEMPS
EARLY THIS MORNING IN THE TEENS TO MID 20S...SLOWLY FALLING INTO
THE SINGLE DIGITS BY THIS AFTERNOON. FOR RUTLAND/WINDSOR...TEMPS
REMAIN STEADY OR CLIMB A BIT INTO THE UPPER 20S TO LOWER 30S BEFORE
DROPPING BEHIND THE FRONT THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
AS OF 415 AM EST MONDAY...DRIER AIR BEGINS TO MOVE IN TONIGHT AS
SURFACE HIGH PRESSURE BUILDS INTO THE REGION ALONG WITH STRONG
COLD AIR ADVECTION ON NORTHERLY FLOW. TOUGH TO TELL HOW MUCH
CLEARING WE`LL SEE AS AN UPPER TROUGH REMAINS OVER THE NORTHEAST
AND THERE`S LOTS OF CLOUD COVER UPSTREAM...BUT THINK WE WILL SEE
SOME BREAKS AND WILL HEDGE TOWARDS PARTLY CLOUDY. THE RETURN OF
ABNORMALLY COLD TEMPERATURES BEGINS TONIGHT THOUGH WHICH WILL
REMAIN ACROSS THE REGION THROUGH MUCH OF THE WEEK. EXPECT LOWS TO
RANGE FROM ZERO TO 15 BELOW TONIGHT...AND WHILE WINDS WILL BE
RATHER LIGHT (4-8 MPH)...THEY`LL BE STRONG ENOUGH TO PRODUCE WIND
CHILLS ACROSS THE MAJORITY OF THE AREA ON THE ORDER OF 20-30 DEGREES
BELOW ZERO. AN ADVISORY HAS BEEN POSTED THROUGH MID-DAY TUESDAY.
FOR THE REMAINDER OF THE SHORT TERM PERIOD PARTLY CLOUDY AND COLD
WILL BE THE RULE AS AFOREMENTIONED SURFACE HIGH SLOWLY SHIFTS
OVER THE REGION AND A BROAD UPPER TROUGH REMAINS ALOFT. HIGH
TEMPS WILL STRUGGLE BOTH TUESDAY AND WEDNESDAY TO GET ABOVE
ZERO...BUT LIKELY WILL BY JUST A FEW DEGREES ACROSS THE
NORTH...AND 5-10 ABOVE SOUTH. WE`LL LIKELY HAVE A REPEAT OF
DANGEROUSLY COLD WIND CHILLS TUESDAY NIGHT AS WELL AS TEMPS DROP
A FEW DEGREES COLDER THAN MONDAY NIGHT AND WINDS REMAIN ABOUT
5-10 MPH OUT OF THE NORTHWEST. I ENVISION ANOTHER ADVISORY BEING
NEEDED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 450 AM EST MONDAY...ECMWF AND GFS MODELS SHOW VERY COLD
ARCTIC AIR WILL BE ENTRENCHED OVER THE REGION FROM WEDNESDAY NIGHT
THROUGH EARLY FRIDAY AS RIDGE OF HIGH PRESSURE WILL BE OVER THE
REGION. EXPECTING LOW TEMPERATURES WEDNESDAY NIGHT AND THURSDAY
NIGHT TO BE BELOW ZERO ACROSS THE REGION...WITH HIGHS ON THURSDAY
ONLY ZERO TO 10 ABOVE ZERO. THE RIDGE OF HIGH PRESSURE MOVES SOUTH
OF THE REGION DURING THE DAY ON FRIDAY. THIS ALLOWS SOUTHERLY
SURFACE WINDS TO DEVELOP OVER THE REGION WITH HIGHS MAINLY 10 TO
15 ABOVE ZERO ON FRIDAY...AND LOW TEMPERATURES FRIDAY NIGHT
REMAINING ABOVE ZERO. ECMWF AND GFS MODELS HINTING AT SOME LAKE
EFFECT SNOW SHOWERS POSSIBLE ACROSS THE SAINT LAWRENCE VALLEY IN
NORTHERN NEW YORK DURING THE DAY ON FRIDAY...SO HAVE SLIGHT CHANCE
POPS FOR SNOW SHOWERS IN THE SAINT LAWRENCE VALLEY ON FRIDAY.
EXPECTING A CHANCE OF SNOW SHOWERS ON SATURDAY DUE TO WARM AIR
ADVECTION ACROSS THE REGION AHEAD OF ANOTHER ARCTIC COLD FRONT
MOVING SOUTHEAST FROM CANADA. ECMWF AND GFS MODELS HOWEVER ARE
SHOWING SOME TIMING DIFFERENCES WITH THE COLD FRONT...WITH THE
ECMWF MODEL FASTER THAN THE GFS MODEL. THE ECMWF MODEL HAS THIS
ARCTIC FRONT EAST OF THE REGION BY EARLY SATURDAY EVENING...WHILE
THE GFS MODEL STILL HAS THIS ARCTIC COLD FRONT IN CANADA
APPROACHING THE SAINT LAWRENCE VALLEY EARLY SATURDAY NIGHT. ECMWF
MODEL SUGGESTS A DRIER FORECAST FOR SATURDAY NIGHT...WHILE THE GFS
MODEL KEEPS IN A CHANCE FOR SOME SNOW SHOWERS. WILL STAY WITH
PREVIOUS CONTINUITY AND KEEP A CHANCE OF SNOW SHOWERS IN THE
FORECAST FOR SATURDAY NIGHT. ECMWF AND GFS MODELS ALSO SHOW A
CHANCE FOR SNOW SHOWERS ON SUNDAY...BUT HAVE DIFFERENT SOLUTIONS.
THE GFS MODEL DEVELOPS A LOW OFF THE SOUTHERN NEW ENGLAND COAST ON
SATURDAY...WHILE THE ECMWF MODEL HAS A LOW TRACKING EAST FROM THE
GREAT LAKES ON SUNDAY. ANYWAY...BOTH MODELS SUGGESTING A CHANCE OF
SNOW SHOWERS ON SUNDAY...BUT DIFFER ON THEIR RESPECTIVE SOLUTIONS.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
THROUGH 06Z TUESDAY...AN ARCTIC COLD FRONT WILL MOVE SOUTH THROUGH
VERMONT AND NORTHERN NEW YORK TODAY WITH SOME BRIEF AREAS OF IFR
IN SNOW SHOWERS THIS MORNING. THE ARCTIC COLD FRONT WILL BE SOUTH
OF THE REGION BY 18Z MONDAY. EXPECTING MAINLY VFR CONDITIONS AFTER
18Z MONDAY...BUT WILL LIKELY SEE SOME AREAS OF MVFR CEILINGS WITH
LIGHT SNOW OVER THE ADIRONDACKS AND GREEN MOUNTAINS CONTINUING
AFTER 18Z MONDAY.
OUTLOOK 06Z TUESDAY THROUGH FRIDAY...
06Z TUESDAY THRU FRIDAY...MAINLY VFR WITH HIGH PRESSURE AND VERY
COLD TEMPERATURES.
&&
.EQUIPMENT...
AS OF 415 AM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR VTZ001>004-006>008-010-016>019.
NY...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ026>031-034-087.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...WGH
AVIATION...WGH/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
418 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CONTINUE TO PRODUCE PERIODS OF SNOW
SHOWERS AND POSSIBLE SNOW SQUALLS AS IT MOVES SOUTHEASTWARD
ACROSS THE NORTH COUNTRY TODAY. BEHIND THE FRONT...A RETURN OF
MUCH COLDER AND DRIER CONDITIONS IS EXPECTED FOR THE UPCOMING
WEEK. HIGH TEMPERATURES EACH DAY TUESDAY THROUGH THURSDAY WILL BE
ONLY IN THE SINGLE DIGITS ABOVE ZERO...AND LOWS WILL BE IN THE
SINGLE DIGITS TO TEENS BELOW. MILDER TEMPERATURES RETURN FOR
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 415 AM EST MONDAY...ARCTIC FRONT CONTINUES TO MAKE ITS WAY
THROUGH THE BTV CWA THIS MORNING WITH WIDESPREAD SNOW SHOWERS
ACROSS THE MAJORITY OF CENTRAL AND NORTHERN AREAS AT THIS EARLY
HOUR. TRENDS CONTINUE FOR A SLOWER PROGRESSION OF THE FRONT
SOUTHEASTWARD AS A SERIES OF SHORTWAVE TROUGHS NOTED ON LATEST WV
IMAGERY AND RUC PVA ANALYSIS TRAVERSE THE AREA...SO HAVE
CONTINUED TO MENTION LIKELY POPS ACROSS NORTHERN AREAS THROUGH
MID-MORNING...AND ACROSS SOUTHERN AREAS THROUGH THE AFTERNOON.
LOOKING AT UPSTREAM SURFACE OBS...NOT A LOT OF QPF ASSOCIATED WITH
THE FRONT AND EXPECT OVERALL SNOW ACCUMULATIONS TO BE GENERALLY A
DUSTING TO 2"...BUT LOCALIZED SQUALLS REMAIN POSSIBLE WHICH COULD
CRANK OUT AN ADDITIONAL 1-2". TEMPS WILL BE VERY TRICKY TODAY
OWING TO DIFFICULTY TIMING THE PASSAGE OF THE FRONT...BUT AREAS
NORTH OF RUTLAND/WINDSOR COUNTIES WILL LIKELY REALIZE MAX TEMPS
EARLY THIS MORNING IN THE TEENS TO MID 20S...SLOWLY FALLING INTO
THE SINGLE DIGITS BY THIS AFTERNOON. FOR RUTLAND/WINDSOR...TEMPS
REMAIN STEADY OR CLIMB A BIT INTO THE UPPER 20S TO LOWER 30S BEFORE
DROPPING BEHIND THE FRONT THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
AS OF 415 AM EST MONDAY...DRIER AIR BEGINS TO MOVE IN TONIGHT AS
SURFACE HIGH PRESSURE BUILDS INTO THE REGION ALONG WITH STRONG
COLD AIR ADVECTION ON NORTHERLY FLOW. TOUGH TO TELL HOW MUCH
CLEARING WE`LL SEE AS AN UPPER TROUGH REMAINS OVER THE NORTHEAST
AND THERE`S LOTS OF CLOUD COVER UPSTREAM...BUT THINK WE WILL SEE
SOME BREAKS AND WILL HEDGE TOWARDS PARTLY CLOUDY. THE RETURN OF
ABNORMALLY COLD TEMPERATURES BEGINS TONIGHT THOUGH WHICH WILL
REMAIN ACROSS THE REGION THROUGH MUCH OF THE WEEK. EXPECT LOWS TO
RANGE FROM ZERO TO 15 BELOW TONIGHT...AND WHILE WINDS WILL BE
RATHER LIGHT (4-8 MPH)...THEY`LL BE STRONG ENOUGH TO PRODUCE WIND
CHILLS ACROSS THE MAJORITY OF THE AREA ON THE ORDER OF 20-30 DEGREES
BELOW ZERO. AN ADVISORY HAS BEEN POSTED THROUGH MID-DAY TUESDAY.
FOR THE REMAINDER OF THE SHORT TERM PERIOD PARTLY CLOUDY AND COLD
WILL BE THE RULE AS AFOREMENTIONED SURFACE HIGH SLOWLY SHIFTS
OVER THE REGION AND A BROAD UPPER TROUGH REMAINS ALOFT. HIGH
TEMPS WILL STRUGGLE BOTH TUESDAY AND WEDNESDAY TO GET ABOVE
ZERO...BUT LIKELY WILL BY JUST A FEW DEGREES ACROSS THE
NORTH...AND 5-10 ABOVE SOUTH. WE`LL LIKELY HAVE A REPEAT OF
DANGEROUSLY COLD WIND CHILLS TUESDAY NIGHT AS WELL AS TEMPS DROP
A FEW DEGREES COLDER THAN MONDAY NIGHT AND WINDS REMAIN ABOUT
5-10 MPH OUT OF THE NORTHWEST. I ENVISION ANOTHER ADVISORY BEING
NEEDED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 205 PM EST SUNDAY...MODELS SHOWING GOOD RUN TO RUN
CONSISTENCY FOR AN OVERALL QUIET PERIOD THRU THE END OF THE WORK
WEEK. NEXT CHANCE FOR WIDESPREAD PRECIP WILL BE OVER THE WEEKEND.
UPPER LVL TROUGH OVER THE NORTHEAST KEEPS SOME CLOUDS AROUND AS
RIDGING BUILDS JUST TO THE WEST. A WEAKENING SHORTWAVE WILL MOVE
TO THE SOUTH OF THE FA ON THURSDAY...BRINGING ONLY SLGT CHC FOR
SNOW SHOWERS TO SRN VT. COLD AIR CONTINUES WITH 850MB TEMPS
AROUND -24C AND 925MB TEMPS OF -20C TO -26C. AT THE SFC THIS WILL
MEAN WEDNESDAY AND THURSDAY MAX TEMPS IN THE SINGLE DIGITS...WITH
MIN TEMPS WEDNESDAY NIGHT AND THURSDAY NIGHT BELOW ZERO.
ON FRIDAY...SFC RIDGE AXIS SHIFTS TO THE EAST...PUTTING THE NORTH
COUNTRY IN MODERATING SW FLOW...AHEAD OF APPROACHING CLOSED LOW
PRESSURE SYSTEM. WARMING TREND WILL BE NOTICEABLE AT THE SFC WITH
FRIDAY MAX TEMPS IN THE TEENS AND FRIDAY NGT MIN TEMPS ABOVE
ZERO.
GFS STARTS TO BRING SNOW FROM AFOREMENTIONED SYSTEM INTO THE SLV
LATE FRIDAY/FRIDAY NIGHT. ECMWF A LITTLE SLOWER WITH RIDGE SLOW
TO WEAKEN AND SHIFT SE. OVERALL INCREASING THREAT OF SNOW SHOWERS
FRIDAY NGT INTO SATURDAY...WITH BULK OF PRECIP ASSOCIATED WITH
COLD FRONT MOVING THROUGH THE REGION ON SATURDAY INTO SATURDAY
NIGHT. WARM TEMPS NEAR NORMAL ON SATURDAY WILL BE SHORT LIVED
WITH THE COLD FRONTAL PASSAGE BRINGING SUNDAY MAX TEMPS INTO THE
TEENS TO L20S.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
THROUGH 06Z TUESDAY...AN ARCTIC COLD FRONT WILL MOVE SOUTH THROUGH
VERMONT AND NORTHERN NEW YORK TODAY WITH SOME BRIEF AREAS OF IFR
IN SNOW SHOWERS THIS MORNING. THE ARCTIC COLD FRONT WILL BE SOUTH
OF THE REGION BY 18Z MONDAY. EXPECTING MAINLY VFR CONDITIONS AFTER
18Z MONDAY...BUT WILL LIKELY SEE SOME AREAS OF MVFR CEILINGS WITH
LIGHT SNOW OVER THE ADIRONDACKS AND GREEN MOUNTAINS CONTINUING
AFTER 18Z MONDAY.
OUTLOOK 06Z TUESDAY THROUGH FRIDAY...
06Z TUESDAY THRU FRIDAY...MAINLY VFR WITH HIGH PRESSURE AND VERY
COLD TEMPERATURES.
&&
.EQUIPMENT...
AS OF 415 AM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR VTZ001>004-006>008-010-016>019.
NY...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ026>031-034-087.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...KGM
AVIATION...WGH/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1255 AM CST MON JAN 20 2014
.UPDATE...
ISSUED AT 1255 AM CST MON JAN 20 2014
ARCTIC FRONT EXTENDED FROM NEAR REGINA SASKATCHEWAN SOUTHEASTWARD TO
JUST EAST OF MINOT AND JAMESTOWN. MINOT WAS AT 35 DEGREES BUT RUGBY
WAS ON THE OTHER SIDE OF THE FRONT AT 14 AND REPORTING LIGHT SNOW.
JAMESTOWN WAS AT 29 WITH NORTHWEST WINDS ON THE WARM SIDE...BUT
VALLEY CITY WAS AT 19 WITH NORTHEAST WINDS. THE FRONT WAS NEAR
HARVEY WITH LIGHT SNOW AND CALM WINDS AT 27 DEGREES...AND CARRINGTON
WITH LIGHT WINDS AND LIGHT SNOW WITH 25 DEGREES. THE FRONT IS
PROGGED TO CONTINUE MOVING SOUTH-SOUTHWEST TONIGHT...AND CONTINUED
UPPER LEVEL ENERGY MOVING SOUTHEAST ACROSS THE STATE COMBINED WITH
THE FRONT WILL SUPPORT LIGHT SNOW. THE TEMPERATURE CONTRAST ACROSS
THE FRONT IS STEEP...AND THERE MAY BE A MIX OF LIGHT RAIN WITH THE
LIGHT SNOW FOR A SHORT TIME AS THE COLD AIR FILTERS IN BEHIND THE
FRONT. FORECAST SOUNDINGS INDICATED MINOT COULD SEE RAIN OR SNOW
(AND THE MINOT AIR BASE REPORTED LIGHT RAIN FOR A SHORT TIME LATE
SUNDAY EVENING). BISMARCK COULD ALSO SEE A SHORT PERIOD OF LIGHT
RAIN...BUT THE JAMESTOWN SOUNDING INDICATED ALL SNOW THERE.
CURRENT FORECAST SNOW AMOUNTS SEEM ON TRACK.
NORTHWEST WINDS ON THE WARM SIDE OF THE FRONT ARE EXPECTED TO
INCREASE TONIGHT TO 25 TO 30 MPH...AND LATER THIS MORNING AS THE
COLD FRONT CONTINUES TO PUSH INTO SOUTH DAKOTA THE NORTH WINDS ARE
PROGGED TO INCREASE TO 20 TO 25 MPH AS WELL.
UPDATE ISSUED AT 949 PM CST SUN JAN 19 2014
LOW PRESSURE TROUGH SITUATED FROM NEAR REGINA SASKATCHEWAN
SOUTHEAST THROUGH MINOT AND JAMESTOWN. UPPER LEVEL WAVE ON WV
IMAGERY IS CURRENTLY DROPPING SOUTHEAST THROUGH SOUTHERN
SASKATCHEWAN. AREA OF LIGHT SNOW CURRENTLY INDICATED OVER RENVILLE
AND WESTERN BOTTINEAU COUNTY WITH LIGHTER REFLECTIVITIES NORTHWARD
INTO FAR SOUTHEAST SASKATCHEWAN AND SOUTHWEST MANITOBA. LATEST
MESOSCALE MODELS TRACK THIS AREA OF SNOW SOUTHEAST WITH MORE LIGHT
SNOW FILLING IN FROM THE NORTH AFTER 06 UTC...ASSOCIATED WITH THE
AFOREMENTIONED SHORTWAVE. CURRENT FORECAST TEMPERATURES LOOK
REASONABLE. MAIN ADJUSTMENTS WITH THE EVENING UPDATE WERE UPDATES
TO HOURLY POPS THROUGH THE REMAINDER OF THE EVENING BASED ON CURRENT
RADAR...AND FUTURE POPS BASED ON 02Z RAP AND 00Z NAM.
UPDATE ISSUED AT 635 PM CST SUN JAN 19 2014
LOW STRATUS REMAINS OVER NORTHEAST NORTH DAKOTA...JUST EAST OF THE
FORECAST AREA...WITH INCREASING MID AND HIGH LEVEL CLOUDINESS FROM
THE WEST. MAIN UPDATE THIS EVENING WAS TO CUT BACK ON POPS OVER
THE EASTERN CWA THIS EVENING. COULD BE A FLURRY OR TWO IN THE
STRATUS AND THAT SHOULD SPREAD WEST LATER TONIGHT. SURFACE LOW
WILL CONTINUE TO DROP SOUTHEAST THROUGH SOUTHERN SASKATCHEWAN THIS
EVENING. 22Z HRRR AND 23Z RAP MESOSCALE MODELS ARE INDICATING
INCREASING POPS FROM NORTH TO SOUTH AFTER 06Z. ALSO ADJUSTED SKY
COVER BASED ON LATEST SATELLITE IMAGERY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE MAIN FOCUS OF TODAY`S FORECAST IS WIND TOMORROW. 12 UTC
NAM/GFS SOUNDINGS SUGGEST THERE WILL BE AT LEAST A COUPLE HOUR
PERIOD OF FAVORABLE MIXING CONDITIONS WITH WINDS A LITTLE OVER 40
KNOTS AT THE TOP OF THE MIXED LAYER. THERE IS CONSIDERABLE
UNCERTAINTY AS THE GFS IS MUCH FASTER TO SQUASH MIXING THAN THE
NAM...SUGGESTING THAT GOOD DOWNWARD MOMENTUM TRANSFER MAY NOT EVEN
MATERIALIZE. THE FORECAST REMAINS BELOW WIND ADVISORY
CRITERIA...BUT THAT WILL NEED TO BE WATCHED CLOSELY.
RIGHT NOW...THE BACKDOOR COLD FRONT SLOWLY MOVING TOWARD THE
TURTLE MOUNTAINS SHOULD SPEED UP ONCE THE WEAK LOW PRESSURE CENTER
OVER SOUTHEASTERN SASKATCHEWAN SLIDES ACROSS THE DEVILS LAKE BASIN
THIS EVENING. LIGHT SNOW WILL ACCOMPANY THE FRONTAL ZONE...AND
THERE IS GREAT MODEL AGREEMENT THAT UP TO 2 INCHES WILL FALL ALONG
THE U.S. HIGHWAY 83 CORRIDOR AND EAST.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 237 PM CST SUN JAN 19 2014
THE NORTHERN PLAINS REMAINS UNDER A QUASI-ACTIVE NORTHWEST FLOW
ALOFT DURING ALL OF THE COMING WORK WEEK AND THROUGH NEXT WEEKEND.
WILL SEE SEVERAL EMBEDDED S/WV`S TRAVERSING NORTH DAKOTA WITHIN THE
FLOW ALOFT BRINGING CHANCES FOR PRECIPITATION ALONG WITH POSSIBLE
NON-DIURNAL TEMPERATURE SWINGS.
THE LONG TERM BEGINS MONDAY NIGHT WITH A STRONG 1040MB SURFACE HIGH
PROPAGATING SOUTH-SOUTHEAST ACROSS THE DAKOTAS TOWARDS THE UPPER
MISSISSIPPI RIVER VALLEY. TUESDAY MORNING LOWS WILL NEAR 20 BELOW
OVER MY EAST...BUT SHOULD REMAIN CLOSER TO 15 BELOW WITH CLOUDS
EXPECTED TO INCREASE THERE AFTER MIDNIGHT. WARMER WEST...ZERO TO THE
SINGLE DIGITS ABOVE...THANKS TO RETURN FLOW/WEAK WAA.
FIRST IN A SERIES OF EMBEDDED IMPULSES WILL MOVE THROUGH THE REGION
TUESDAY...FOLLOWED BY A BROADER S/WV TROUGH WEDNESDAY. EACH OF THESE
FEATURES WILL BRING A CHANCE FOR SNOW...THE FIRST ACROSS THE EASTERN
THIRD OF THE STATE (GRAZING MY FAR EASTERN COUNTIES) AND THE SECOND
MORE WIDESPREAD WITH LIGHT SNOW ACROSS WEST AND CENTRAL ND. LIMITED
MOISTURE WITH EACH FEATURE SO NOT EXPECTING MUCH IN THE WAY OF
ACCUMULATING SNOWFALL. THE TROUGH ON WEDNESDAY WILL BRING STRONG CAA
ACROSS THE NORTHERN PLAINS...WITH FALLING TEMPERATURES LIKELY
WEDNESDAY THROUGH WEDNESDAY NIGHT. WITH WIND SPEEDS NEAR
10KTS...WILL NEED TO MONITOR FOR POSSIBLE WIND CHILL HEADLINES
DURING THE DAY WEDNESDAY AND FOR WEDNESDAY NIGHT/THURSDAY MORNING
WITH SUBZERO TEMPERATURES.
MODEL UNCERTAINTY INCREASES FROM THE END OF THE WORK WEEK THROUGH
NEXT WEEKEND. BOTH THE 12Z GFS AND ECMWF DIFFER ON THE TIMING AND
PLACEMENT OF POSSIBLE WAVES MOVING THROUGH IN THE FLOW ALOFT...AND
ARE ALSO FLUCTUATING MODEL RUN TO RUN. OVERALL...THE ACTIVE PATTERN
REMAINS IN PLACE...WITH THE THERMAL BOUNDARY REMAINING
QUASI-STATIONARY WITH COLDER TEMPERATURES NORTHEAST AND WARMER
SOUTHWEST. THE VERY COLD AIR PREVIOUSLY ADVERTISED FOR NEXT WEEKEND
IS NOW CONSISTENTLY (OVER THE LAST 3-4 GFS/ECMWF RUNS) BEING
DEPICTED TO REMAIN WELL TO OUR EAST OVER THE GREAT LAKES...ALTHOUGH
WE MAY STILL EXPERIENCE THE WESTERN EDGE OF THIS ARCTIC AIRMASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1255 AM CST MON JAN 20 2014
MVFR TO IFR STRATUS BEHIND A COLD FRONT WILL MOVE SLOWLY
SOUTHWARD OVER ALL TAF SITES TONIGHT. SNOW WILL LAG THE CLOUDS BY
A FEW HOURS AT KJMS/KMOT/KBIS. SOME BLOWING SNOW IS POSSIBLE...BUT
IS HIGHLY DEPENDENT UPON AMOUNT AND TIMING OF SNOWFALL.
THEREAFTER...LOW STRATUS WILL LIKELY REMAIN THROUGH THE MORNING
THEN DECREASE FROM NORTH TO SOUTH DURING THE AFTERNOON MONDAY.
NORTHWEST WINDS AHEAD OF THE FRONT INCREASING TO 20-25 KNOTS. WINDS
BEHIND THE COLD FRONT BECOME NORTHERLY...INCREASING TO 15 TO 20
KNOTS. WINDS DECREASING MONDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAY ME
1042 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. HIGH PRESSURE BUILDS
IN FROM THE WEST TUESDAY AND WEDNESDAY AS LOW PRESSURE PASSES BY
OFFSHORE. HIGH PRESSURE BUILDS ACROSS THE REGION THURSDAY AND FRIDAY.
A WEAK WARM FRONT WILL CROSS THE REGION SATURDAY FOLLOWED BY A
STRONG ARCTIC FRONT ON SUNDAY.
&&
.NEAR TERM /TODAY/...
1030AM UPDATE...
HAVE MADE ANOTHER BRIEF UPDATE TO ADJUST SKY COVER FORECAST. SOME
CLEARING HAS BEEN NOTED ACROSS SOUTHERN NEW HAMPSHIRE AND CENTRAL
MASSACHUSETTS AS A MID LEVEL CLOUD LAYER MOVES OFF TO THE EAST.
LOW LEVEL CLOUD LAYER WILL BE BANKED UP AGAINST THE TERRAIN AND
DOWNSLOPING TO THE SOUTHEAST OF THE TERRAIN MAY KEEP IT FROM BEING
A TOTALLY CLOUDY DAY FOR THE COASTAL PLAIN.
930AM UPDATE...
COLD FRONT HAS NOW PUSHED INTO NORTHWESTERN AREAS OF MAINE AND NEW
HAMPSHIRE. FRONT HAS CROSSED BERLIN NEW HAMPSHIRE WITH
TEMPERATURES DROPPING 3 DEGREES AS IT MOVED IN. TEMPERATURES HAVE
BEEN DROPPING BEHIND THE FRONT CONSISTENTLY ACROSS VERMONT AND
CANADA THIS MORNING... AND EXPECT THIS TO CONTINUE AS IT MOVES
THROUGH NEW HAMPSHIRE AND MAINE. SOME LIGHT SNOW HAS BEEN OBSERVED
ALONG AND AHEAD OF THE FRONT. MINOR INSTABILITY COULD LEAD TO SNOW
SQUALLS AS THE FRONT MOVES THROUGH ESPECIALLY IN TERRAIN ENHANCED
AREAS. HAVE ADJUSTED THE POP FORECAST TO SHOW THE PROGRESSION OF
SNOW CHANCES ACROSS THE AREA TODAY AND HAVE ALSO ADJUSTED
TEMPERATURES TO REFLECT WARMING AHEAD OF THE FRONT AND COOLING
BEHIND IT AS IT CROSSES THE FORECAST AREA TODAY.
630AM UPDATE...
THE ARCTIC FRONT CONTINUES TO PLOW SOUTHEASTWARD ACROSS THE
REGION WITH THE FRONTAL PASSAGE NEAR THE BML TO GNR REGION AS OF
1130Z. LATEST HRRR RUN CONTINUES TO SHOW A FEW SNOW SHOWERS
CROSSING THE REGION...WITH PERHAPS A BRIEF SQUALL IN THE MOUNTAINS
TODAY.
HAVE ADJUSTED TEMPERATURES BASED ON CURRENT CONDITIONS AS OF 11Z.
ADJUSTED CLOUDS/POPS AND DEW POINTS AS WELL.
ORIGINAL DISCUSSION...
AN ARCTIC FRONT WILL CROSS THE FORECAST AREA TODAY. THE LATEST
HRRR RUN HAS THE SYSTEM REACHING THE COASTLINE BY ABOUT 19Z. IN
ITS WAKE THERE WILL BE SCATTERED SNOW SHOWERS...AND WITH A
DESTABILIZED ATMOSPHERE...THERE WILL BE THE POSSIBILITY OF A BRIEF
SQUALL WITH THIS EVENT. BEST CHANCE WILL BE IN THE MOUNTAINS AND
FOOTHILLS TODAY.
TEMPERATURES WILL LIKELY HOLD RELATIVELY STEADY TODAY IN THE
20S IN THE MOUNTAINS...WITH READINGS TOPPING OUT WELL INTO THE 30S
AHEAD OF THE ARCTIC FRONT OVER SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND TUESDAY/...
ARCTIC CHILL ARRIVES IN FULL STEAM TONIGHT. FOLLOWED THE COLDER
MET MOS GUIDANCE WHICH BRINGS THE MOUNTAINS INTO THE 10 TO 15
BELOW ZERO RANGE. WITH NORTHWEST BREEZES CONTINUING...WILL NEED
WIND CHILL WARNINGS IN THE MOUNTAINS...AND ADVISORIES SURROUNDING
THIS REGION IN THE FOOTHILLS.
ON TUESDAY...THE GFS IS THE MOST AGGRESSIVE IN DEVELOPING LOW
PRESSURE OFF THE MID ATLANTIC COASTLINE AS THE UPPER LEVEL SUPPORT
TAKES ON A NEUTRAL TILT. HAVE INCLUDED CHANCE POPS OVER SOUTHERN
AREAS AS THE SURFACE LOW BRUSHES BY TO OUR SOUTH AND EAST. COULD
GO HIGHER ON THE POPS HOWEVER ALL OTHER MODELS CONTINUE TO SHOW A
MORE PROGRESSIVE...OUT TO SEA SOLUTION. HOWEVER...IF MODELS TREND
WESTWARD WITH THIS SYSTEM...WE COULD SEE LIGHT ACCUMULATIONS OF
SNOW ALONG AND NEAR THE COAST BY LATE TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON KEEPING DEVELOPMENT OF OFFSHORE STORM FAR ENOUGH
EAST TO ONLY POSSIBLY GRAZE PORTIONS OF MAINE AND NEW HAMPSHIRE
TUESDAY NIGHT AND WEDNESDAY MORNING WITH SOME LIGHT SNOW. AS THE
SYSTEM RAPIDLY EXITS TO THE NORTHEAST WEDNESDAY AFTERNOON MUCH
COLDER AIR WILL FOLLOW INTO THE AREA WEDNESDAY NIGHT THRU FRIDAY
AS HIGH PRESSURE GRADUALLY BUILDS ACROSS THE NORTHEAST STATES.
TEMPERATURES MAY MODIFY A LITTLE SATURDAY AHEAD OF AN ALBERTA
CLIPPER THAT WILL DRIVE SOUTHEAST FOR SUNDAY BEING ACCOMPANIED BY
SNOW SHOWERS AND SOME OF THE COLDEST AIR OF THE WINTER LATE SUNDAY
INTO EARLY NEXT WEEK.
SINCE THERE ARE NO MAJOR STORMS EXPECTED IN THE OUTLOOK PERIOD.
THE MAIN CONCERN WILL BE THE PERIODS OF BITTER COLD TEMPERATURES
AT TIMES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
SHORT TERM...VFR CONDITIONS EXPECTED...HOWEVER SCATTERED SNOW
SHOWERS MAY LOCALLY DROP VSBYS/CIGS TODAY WITH THE ARCTIC FRONTAL
PASSAGE.
LONG TERM...GENERALLY VFR CONDITIONS.
&&
.MARINE...
SHORT TERM....SMALL CRAFT ADVISORIES ARE NOW IN EFFECT THROUGH
TONIGHT FOR ALL AREAS. LIGHT TO MODERATE FREEZING SPRAY WILL
DEVELOP THIS EVENING AS WINDS INCREASE BEHIND A COLD FRONT.
LONG TERM...GUSTS TO 25 KT OR HIGHER ARE POSSIBLE TUESDAY NIGHT
INTO WEDNESDAY AS COLD ADVECTION OCCURS ACROSS THE WATERS. THIS
VERY COLD AIR WILL BE COLD ENOUGH TO PRODUCE FREEZING SPRAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR MEZ007>009.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR MEZ012>014.
NH...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR NHZ001-002.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR NHZ003-004.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ150>154.
&&
$$
SYNOPSIS...CANNON
NEAR TERM UPDATE...KIMBLE
SHORT TERM...CANNON
LONG TERM...MARINE
AVIATION...CANNON/MARINE
MARINE...CANNON/MARINE
AREA FORECAST DISCUSSION
NWS GRAY ME
936 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. HIGH PRESSURE BUILDS
IN FROM THE WEST TUESDAY AND WEDNESDAY AS LOW PRESSURE PASSES BY
OFFSHORE. HIGH PRESSURE BUILDS ACROSS THE REGION THURSDAY AND FRIDAY.
A WEAK WARM FRONT WILL CROSS THE REGION SATURDAY FOLLOWED BY A
STRONG ARCTIC FRONT ON SUNDAY.
&&
.NEAR TERM /TODAY/...
930AM UPDATE...
COLD FRONT HAS NOW PUSHED INTO NORTHWESTERN AREAS OF MAINE AND NEW
HAMPSHIRE. FRONT HAS CROSSED BERLIN NEW HAMPSHIRE WITH
TEMPERATURES DROPPING 3 DEGREES AS IT MOVED IN. TEMPERATURES HAVE
BEEN DROPPING BEHIND THE FRONT CONSISTENTLY ACROSS VERMONT AND
CANADA THIS MORNING... AND EXPECT THIS TO CONTINUE AS IT MOVES
THROUGH NEW HAMPSHIRE AND MAINE. SOME LIGHT SNOW HAS BEEN OBSERVED
ALONG AND AHEAD OF THE FRONT. MINOR INSTABILITY COULD LEAD TO SNOW
SQUALLS AS THE FRONT MOVES THROUGH ESPECIALLY IN TERRAIN ENHANCED
AREAS. HAVE ADJUSTED THE POP FORECAST TO SHOW THE PROGRESSION OF
SNOW CHANCES ACROSS THE AREA TODAY AND HAVE ALSO ADJUSTED
TEMPERATURES TO REFLECT WARMING AHEAD OF THE FRONT AND COOLING
BEHIND IT AS IT CROSSES THE FORECAST AREA TODAY.
630AM UPDATE...
THE ARCTIC FRONT CONTINUES TO PLOW SOUTHEASTWARD ACROSS THE
REGION WITH THE FRONTAL PASSAGE NEAR THE BML TO GNR REGION AS OF
1130Z. LATEST HRRR RUN CONTINUES TO SHOW A FEW SNOW SHOWERS
CROSSING THE REGION...WITH PERHAPS A BRIEF SQUALL IN THE MOUNTAINS
TODAY.
HAVE ADJUSTED TEMPERATURES BASED ON CURRENT CONDITIONS AS OF 11Z.
ADJUSTED CLOUDS/POPS AND DEW POINTS AS WELL.
ORIGINAL DISCUSSION...
AN ARCTIC FRONT WILL CROSS THE FORECAST AREA TODAY. THE LATEST
HRRR RUN HAS THE SYSTEM REACHING THE COASTLINE BY ABOUT 19Z. IN
ITS WAKE THERE WILL BE SCATTERED SNOW SHOWERS...AND WITH A
DESTABILIZED ATMOSPHERE...THERE WILL BE THE POSSIBILITY OF A BRIEF
SQUALL WITH THIS EVENT. BEST CHANCE WILL BE IN THE MOUNTAINS AND
FOOTHILLS TODAY.
TEMPERATURES WILL LIKELY HOLD RELATIVELY STEADY TODAY IN THE
20S IN THE MOUNTAINS...WITH READINGS TOPPING OUT WELL INTO THE 30S
AHEAD OF THE ARCTIC FRONT OVER SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND TUESDAY/...
ARCTIC CHILL ARRIVES IN FULL STEAM TONIGHT. FOLLOWED THE COLDER
MET MOS GUIDANCE WHICH BRINGS THE MOUNTAINS INTO THE 10 TO 15
BELOW ZERO RANGE. WITH NORTHWEST BREEZES CONTINUING...WILL NEED
WIND CHILL WARNINGS IN THE MOUNTAINS...AND ADVISORIES SURROUNDING
THIS REGION IN THE FOOTHILLS.
ON TUESDAY...THE GFS IS THE MOST AGGRESSIVE IN DEVELOPING LOW
PRESSURE OFF THE MID ATLANTIC COASTLINE AS THE UPPER LEVEL SUPPORT
TAKES ON A NEUTRAL TILT. HAVE INCLUDED CHANCE POPS OVER SOUTHERN
AREAS AS THE SURFACE LOW BRUSHES BY TO OUR SOUTH AND EAST. COULD
GO HIGHER ON THE POPS HOWEVER ALL OTHER MODELS CONTINUE TO SHOW A
MORE PROGRESSIVE...OUT TO SEA SOLUTION. HOWEVER...IF MODELS TREND
WESTWARD WITH THIS SYSTEM...WE COULD SEE LIGHT ACCUMULATIONS OF
SNOW ALONG AND NEAR THE COAST BY LATE TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS AGREE ON KEEPING DEVELOPMENT OF OFFSHORE STORM FAR ENOUGH
EAST TO ONLY POSSIBLY GRAZE PORTIONS OF MAINE AND NEW HAMPSHIRE
TUESDAY NIGHT AND WEDNESDAY MORNING WITH SOME LIGHT SNOW. AS THE
SYSTEM RAPIDLY EXITS TO THE NORTHEAST WEDNESDAY AFTERNOON MUCH
COLDER AIR WILL FOLLOW INTO THE AREA WEDNESDAY NIGHT THRU FRIDAY
AS HIGH PRESSURE GRADUALLY BUILDS ACROSS THE NORTHEAST STATES.
TEMPERATURES MAY MODIFY A LITTLE SATURDAY AHEAD OF AN ALBERTA
CLIPPER THAT WILL DRIVE SOUTHEAST FOR SUNDAY BEING ACCOMPANIED BY
SNOW SHOWERS AND SOME OF THE COLDEST AIR OF THE WINTER LATE SUNDAY
INTO EARLY NEXT WEEK.
SINCE THERE ARE NO MAJOR STORMS EXPECTED IN THE OUTLOOK PERIOD.
THE MAIN CONCERN WILL BE THE PERIODS OF BITTER COLD TEMPERATURES
AT TIMES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
SHORT TERM...VFR CONDITIONS EXPECTED...HOWEVER SCATTERED SNOW
SHOWERS MAY LOCALLY DROP VSBYS/CIGS TODAY WITH THE ARCTIC FRONTAL
PASSAGE.
LONG TERM...GENERALLY VFR CONDITIONS.
&&
.MARINE...
SHORT TERM....SMALL CRAFT ADVISORIES ARE NOW IN EFFECT THROUGH
TONIGHT FOR ALL AREAS. LIGHT TO MODERATE FREEZING SPRAY WILL
DEVELOP THIS EVENING AS WINDS INCREASE BEHIND A COLD FRONT.
LONG TERM...GUSTS TO 25 KT OR HIGHER ARE POSSIBLE TUESDAY NIGHT
INTO WEDNESDAY AS COLD ADVECTION OCCURS ACROSS THE WATERS. THIS
VERY COLD AIR WILL BE COLD ENOUGH TO PRODUCE FREEZING SPRAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR MEZ007>009.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR MEZ012>014.
NH...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR NHZ001-002.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR NHZ003-004.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ150>154.
&&
$$
SYNOPSIS...CANNON
NEAR TERM UPDATE...KIMBLE
SHORT TERM...CANNON
LONG TERM...MARINE
AVIATION...CANNON/MARINE
MARINE...CANNON/MARINE
AREA FORECAST DISCUSSION
NWS GRAY ME
624 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. HIGH PRESSURE BUILDS
IN FROM THE WEST TUESDAY AND WEDNESDAY AS LOW PRESSURE PASSES BY
OFFSHORE. HIGH PRESSURE BUILDS ACROSS THE REGION THURSDAY AND FRIDAY.
A WEAK WARM FRONT WILL CROSS THE REGION SATURDAY FOLLOWED BY A
STRONG ARCTIC FRONT ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...THE ARCTIC FRONT CONTINUES TO PLOW SOUTHEASTWARD ACROSS
THE REGION WITH THE FROPA NEAR THE BML TO GNR REGION AS OF 1130Z.
LATEST HRRR RUN CONTINUES TO SHOW A FEW SNOW SHOWERS CROSSING THE
REGION...WITH PERHAPS A BRIEF SQUALL IN THE MOUNTAINS TODAY.
HAVE ADJUSTED TEMPERATURES BASED ON CURRENT CONDITIONS AS OF 11Z.
ADJUSTED CLOUDS/POPS AND DEW POINTS AS WELL.
PREV DISC...AN ARCTIC FRONT WILL CROSS THE FORECAST AREA TODAY.
THE LATEST HRRR RUN HAS THE SYSTEM REACHING THE COASTLINE BY ABOUT
19Z. IN ITS WAKE THERE WILL BE SCATTERED SNOW SHOWERS...AND WITH A
DESTABILIZED ATMOSPHERE...THERE WILL BE THE POSSIBILITY OF A BRIEF
SQUALL WITH THIS EVENT. BEST CHANCE WILL BE IN THE MOUNTAINS AND
FOOTHILLS TODAY.
TEMPERATURES WILL LIKELY HOLD RELATIVELY STEADY TODAY IN THE
20S IN THE MOUNTAINS...WITH READINGS TOPPING OUT WELL INTO THE 30S
AHEAD OF THE ARCTIC FRONT OVER SOUTHERN AREAS.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
ARCTIC CHILL ARRIVES IN FULL STEAM TONIGHT. FOLLOWED THE COLDER
MET MOS GUIDANCE WHICH BRINGS THE MOUNTAINS INTO THE 10 TO 15
BELOW ZERO RANGE. WITH NORTHWEST BREEZES CONTINUING...WILL NEED
WIND CHILL WARNINGS IN THE MOUNTAINS...AND ADVISORIES SURROUNDING
THIS REGION IN THE FOOTHILLS.
ON TUESDAY...THE GFS IS THE MOST AGRESSIVE IN DEVELOPING LOW
PRESSURE OFF THE MID ATLANTIC COASTLINE AS THE UPPER LEVEL SUPPORT
TAKES ON A NEUTRAL TILT. HAVE INCLUDED CHANCE POPS OVER SOUTHERN
AREAS AS THE SURFACE LOW BRUSHES BY TO OUR SOUTH AND EAST. COULD
GO HIGHER ON THE POPS HOWEVER ALL OTHER MODELS CONTINUE TO SHOW A
MORE PROGRESSIVE...OUT TO SEA SOLUTION. HOWEVER...IF MODELS TREND
WESTWARD WITH THIS SYSTEM...WE COULD SEE LIGHT ACCUMULATIONS OF
SNOW ALONG AND NEAR THE COAST BY LATE TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS AGREE ON KEEPING DEVELOPMENT OF OFFSHORE STORM FAR ENOUGH
EAST TO ONLY PSBLY GRAZE PORTIONS OF MAINE AND NEW HAMPSHIRE
TUESDAY NIGHT AND WED MRNG WITH SOME LGT SNOW. AS THE SYSTEM
RAPIDLY EXITS TO THE NORTHEAST WED AFTERNOON MUCH COLDER AIR WILL
FOLLOW INTO THE AREA WED NIGHT THRU FRI AS HIGH PRES GRDLY BUILDS
ACROSS THE NERN US. TEMPS MAY MODIFY A LITTLE SAT AHEAD OF AN ALBERTA
CLIPPER THAT WILL DRIVE SEWD FOR SUNDAY BEING ACCOMPANIED BY SNW
SHWRS AND SOME OF THE COLDEST AIR OF THE WINTER LATE SUNDAY INTO
EARLY NEXT WEEK.
SINCE THERE ARE NO MAJOR STORMS EXPECTED IN THE OUTLOOK PERIOD.
THE MAIN CONCERN WILL BE THE PERIODS OF BITTER COLD TEMPS AT TIMES.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
SHORT TERM...VFR CONDITIONS EXPECTED...HOWEVER SCATTERED SNOW
SHOWERS MAY LOCALLY DROP VSBYS/CIGS TODAY WITH THE ARCTIC FRONTAL PASSAGE.
LONG TERM...GENERALLY VFR CONDITIONS.
&&
.MARINE...
SHORT TERM....SMALL CRAFT ADVISORIES ARE NOW IN EFFECT THROUGH
TONIGHT FOR ALL AREAS. LIGHT TO MODERATE FREEZING SPRAY WILL
DEVELOP THIS EVENING AS WINDS INCREASE BEHIND A COLD FRONT.
LONG TERM...GUSTS TO 25 KT OR HIGHER ARE POSSIBLE TUESDAY NIGHT
INTO WEDNESDAY AS COLD ADVECTION OCCURS ACROSS THE WATERS. THIS
VERY COLD AIR WILL BE COLD ENOUGH TO PRODUCE FREEZING SPRAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR MEZ007>009.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR MEZ012>014.
NH...WIND CHILL WARNING FROM 11 PM THIS EVENING TO 9 AM EST TUESDAY
FOR NHZ001-002.
WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 9 AM EST
TUESDAY FOR NHZ003-004.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
941 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CONTINUE TO PRODUCE PERIODS OF SNOW
SHOWERS AND POSSIBLE SNOW SQUALLS AS IT MOVES SOUTHEASTWARD
ACROSS THE NORTH COUNTRY TODAY. BEHIND THE FRONT...A RETURN OF
MUCH COLDER AND DRIER CONDITIONS IS EXPECTED FOR THE UPCOMING
WEEK. HIGH TEMPERATURES EACH DAY TUESDAY THROUGH THURSDAY WILL BE
ONLY IN THE SINGLE DIGITS ABOVE ZERO...AND LOWS WILL BE IN THE
SINGLE DIGITS TO TEENS BELOW. MILDER TEMPERATURES RETURN FOR
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 931 AM EST MONDAY...SOME MINOR CHANGES TO FORECAST WITH
LATEST UPDATE TO REFLECT CURRENT CONDITIONS AND TRENDS. SNOW
CONTINUES TO FALL ACROSS MOST OF FORECAST AT THIS TIME AS ARCTIC
FRONT MAKES ITS WAY SOUTH ACROSS CENTRAL VERMONT. SNOW BEGINNING
TO WIND DOWN IN SAINT LAWRENCE VALLEY AS DRIER AIR WORKS IN FROM
THE NORTHWEST. EXPECT THIS DRYING TREND TO SPREAD SLOWLY
SOUTHEASTWARD FOR THE REST OF TODAY. HAVE INCREASED POPS FOR REST
OF THE MORNING FOR MOST AREAS...AND ADJUSTED SNOW ACCUMULATIONS UP
SLIGHTLY. TEMPS WILL BE STEADY OR FALLING MOST AREAS. LOOK FOR
MIDDAY READINGS TO RANGE FROM SINGLE DIGITS AT MASSENA NY TO
LOWER 30S AT SPRINGFIELD VT.
EARLIER DISCUSSION...
ARCTIC FRONT CONTINUES TO MAKE ITS WAY THROUGH THE BTV CWA THIS
MORNING WITH WIDESPREAD SNOW SHOWERS ACROSS THE MAJORITY OF
CENTRAL AND NORTHERN AREAS AT THIS EARLY HOUR. TRENDS CONTINUE FOR
A SLOWER PROGRESSION OF THE FRONT SOUTHEASTWARD AS A SERIES OF
SHORTWAVE TROUGHS NOTED ON LATEST WV IMAGERY AND RUC PVA ANALYSIS
TRAVERSE THE AREA...SO HAVE CONTINUED TO MENTION LIKELY POPS
ACROSS NORTHERN AREAS THROUGH MID-MORNING...AND ACROSS SOUTHERN
AREAS THROUGH THE AFTERNOON. LOOKING AT UPSTREAM SURFACE OBS...NOT
A LOT OF QPF ASSOCIATED WITH THE FRONT AND EXPECT OVERALL SNOW
ACCUMULATIONS TO BE GENERALLY A DUSTING TO 2"...BUT LOCALIZED
SQUALLS REMAIN POSSIBLE WHICH COULD CRANK OUT AN ADDITIONAL 1-2".
TEMPS WILL BE VERY TRICKY TODAY OWING TO DIFFICULTY TIMING THE
PASSAGE OF THE FRONT...BUT AREAS NORTH OF RUTLAND/WINDSOR COUNTIES
WILL LIKELY REALIZE MAX TEMPS EARLY THIS MORNING IN THE TEENS TO
MID 20S...SLOWLY FALLING INTO THE SINGLE DIGITS BY THIS AFTERNOON.
FOR RUTLAND/WINDSOR...TEMPS REMAIN STEADY OR CLIMB A BIT INTO THE
UPPER 20S TO LOWER 30S BEFORE DROPPING BEHIND THE FRONT THIS
EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
AS OF 415 AM EST MONDAY...DRIER AIR BEGINS TO MOVE IN TONIGHT AS
SURFACE HIGH PRESSURE BUILDS INTO THE REGION ALONG WITH STRONG
COLD AIR ADVECTION ON NORTHERLY FLOW. TOUGH TO TELL HOW MUCH
CLEARING WE`LL SEE AS AN UPPER TROUGH REMAINS OVER THE NORTHEAST
AND THERE`S LOTS OF CLOUD COVER UPSTREAM...BUT THINK WE WILL SEE
SOME BREAKS AND WILL HEDGE TOWARDS PARTLY CLOUDY. THE RETURN OF
ABNORMALLY COLD TEMPERATURES BEGINS TONIGHT THOUGH WHICH WILL
REMAIN ACROSS THE REGION THROUGH MUCH OF THE WEEK. EXPECT LOWS TO
RANGE FROM ZERO TO 15 BELOW TONIGHT...AND WHILE WINDS WILL BE
RATHER LIGHT (4-8 MPH)...THEY`LL BE STRONG ENOUGH TO PRODUCE WIND
CHILLS ACROSS THE MAJORITY OF THE AREA ON THE ORDER OF 20-30 DEGREES
BELOW ZERO. AN ADVISORY HAS BEEN POSTED THROUGH MID-DAY TUESDAY.
FOR THE REMAINDER OF THE SHORT TERM PERIOD PARTLY CLOUDY AND COLD
WILL BE THE RULE AS AFOREMENTIONED SURFACE HIGH SLOWLY SHIFTS
OVER THE REGION AND A BROAD UPPER TROUGH REMAINS ALOFT. HIGH
TEMPS WILL STRUGGLE BOTH TUESDAY AND WEDNESDAY TO GET ABOVE
ZERO...BUT LIKELY WILL BY JUST A FEW DEGREES ACROSS THE
NORTH...AND 5-10 ABOVE SOUTH. WE`LL LIKELY HAVE A REPEAT OF
DANGEROUSLY COLD WIND CHILLS TUESDAY NIGHT AS WELL AS TEMPS DROP
A FEW DEGREES COLDER THAN MONDAY NIGHT AND WINDS REMAIN ABOUT
5-10 MPH OUT OF THE NORTHWEST. I ENVISION ANOTHER ADVISORY BEING
NEEDED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 450 AM EST MONDAY...ECMWF AND GFS MODELS SHOW VERY COLD
ARCTIC AIR WILL BE ENTRENCHED OVER THE REGION FROM WEDNESDAY NIGHT
THROUGH EARLY FRIDAY AS RIDGE OF HIGH PRESSURE WILL BE OVER THE
REGION. EXPECTING LOW TEMPERATURES WEDNESDAY NIGHT AND THURSDAY
NIGHT TO BE BELOW ZERO ACROSS THE REGION...WITH HIGHS ON THURSDAY
ONLY ZERO TO 10 ABOVE ZERO. THE RIDGE OF HIGH PRESSURE MOVES SOUTH
OF THE REGION DURING THE DAY ON FRIDAY. THIS ALLOWS SOUTHERLY
SURFACE WINDS TO DEVELOP OVER THE REGION WITH HIGHS MAINLY 10 TO
15 ABOVE ZERO ON FRIDAY...AND LOW TEMPERATURES FRIDAY NIGHT
REMAINING ABOVE ZERO. ECMWF AND GFS MODELS HINTING AT SOME LAKE
EFFECT SNOW SHOWERS POSSIBLE ACROSS THE SAINT LAWRENCE VALLEY IN
NORTHERN NEW YORK DURING THE DAY ON FRIDAY...SO HAVE SLIGHT CHANCE
POPS FOR SNOW SHOWERS IN THE SAINT LAWRENCE VALLEY ON FRIDAY.
EXPECTING A CHANCE OF SNOW SHOWERS ON SATURDAY DUE TO WARM AIR
ADVECTION ACROSS THE REGION AHEAD OF ANOTHER ARCTIC COLD FRONT
MOVING SOUTHEAST FROM CANADA. ECMWF AND GFS MODELS HOWEVER ARE
SHOWING SOME TIMING DIFFERENCES WITH THE COLD FRONT...WITH THE
ECMWF MODEL FASTER THAN THE GFS MODEL. THE ECMWF MODEL HAS THIS
ARCTIC FRONT EAST OF THE REGION BY EARLY SATURDAY EVENING...WHILE
THE GFS MODEL STILL HAS THIS ARCTIC COLD FRONT IN CANADA
APPROACHING THE SAINT LAWRENCE VALLEY EARLY SATURDAY NIGHT. ECMWF
MODEL SUGGESTS A DRIER FORECAST FOR SATURDAY NIGHT...WHILE THE GFS
MODEL KEEPS IN A CHANCE FOR SOME SNOW SHOWERS. WILL STAY WITH
PREVIOUS CONTINUITY AND KEEP A CHANCE OF SNOW SHOWERS IN THE
FORECAST FOR SATURDAY NIGHT. ECMWF AND GFS MODELS ALSO SHOW A
CHANCE FOR SNOW SHOWERS ON SUNDAY...BUT HAVE DIFFERENT SOLUTIONS.
THE GFS MODEL DEVELOPS A LOW OFF THE SOUTHERN NEW ENGLAND COAST ON
SATURDAY...WHILE THE ECMWF MODEL HAS A LOW TRACKING EAST FROM THE
GREAT LAKES ON SUNDAY. ANYWAY...BOTH MODELS SUGGESTING A CHANCE OF
SNOW SHOWERS ON SUNDAY...BUT DIFFER ON THEIR RESPECTIVE SOLUTIONS.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
THROUGH 12Z TUESDAY...AN ARCTIC COLD FRONT WILL MOVE SOUTH
THROUGH VERMONT AND NORTHERN NEW YORK TODAY WITH AREAS OF IFR IN
SNOW SHOWERS THIS MORNING. THE ARCTIC COLD FRONT WILL BE SOUTH OF
THE REGION BY 18Z MONDAY. EXPECTING MAINLY VFR CONDITIONS AFTER
18Z MONDAY...BUT WILL LIKELY SEE SOME AREAS OF MVFR CEILINGS WITH
LIGHT SNOW OVER THE ADIRONDACKS AND GREEN MOUNTAINS CONTINUING
AFTER 18Z MONDAY.
OUTLOOK 12Z TUESDAY THROUGH FRIDAY...
12Z TUESDAY THRU FRIDAY...MAINLY VFR WITH HIGH PRESSURE AND VERY
COLD TEMPERATURES.
&&
.EQUIPMENT...
AS OF 415 AM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR VTZ001>004-006>008-010-016>019.
NY...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ026>031-034-087.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...RJS/LAHIFF
SHORT TERM...LAHIFF
LONG TERM...WGH
AVIATION...WGH/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
723 AM EST MON JAN 20 2014
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CONTINUE TO PRODUCE PERIODS OF SNOW
SHOWERS AND POSSIBLE SNOW SQUALLS AS IT MOVES SOUTHEASTWARD
ACROSS THE NORTH COUNTRY TODAY. BEHIND THE FRONT...A RETURN OF
MUCH COLDER AND DRIER CONDITIONS IS EXPECTED FOR THE UPCOMING
WEEK. HIGH TEMPERATURES EACH DAY TUESDAY THROUGH THURSDAY WILL BE
ONLY IN THE SINGLE DIGITS ABOVE ZERO...AND LOWS WILL BE IN THE
SINGLE DIGITS TO TEENS BELOW. MILDER TEMPERATURES RETURN FOR
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 415 AM EST MONDAY...ARCTIC FRONT CONTINUES TO MAKE ITS WAY
THROUGH THE BTV CWA THIS MORNING WITH WIDESPREAD SNOW SHOWERS
ACROSS THE MAJORITY OF CENTRAL AND NORTHERN AREAS AT THIS EARLY
HOUR. TRENDS CONTINUE FOR A SLOWER PROGRESSION OF THE FRONT
SOUTHEASTWARD AS A SERIES OF SHORTWAVE TROUGHS NOTED ON LATEST WV
IMAGERY AND RUC PVA ANALYSIS TRAVERSE THE AREA...SO HAVE
CONTINUED TO MENTION LIKELY POPS ACROSS NORTHERN AREAS THROUGH
MID-MORNING...AND ACROSS SOUTHERN AREAS THROUGH THE AFTERNOON.
LOOKING AT UPSTREAM SURFACE OBS...NOT A LOT OF QPF ASSOCIATED WITH
THE FRONT AND EXPECT OVERALL SNOW ACCUMULATIONS TO BE GENERALLY A
DUSTING TO 2"...BUT LOCALIZED SQUALLS REMAIN POSSIBLE WHICH COULD
CRANK OUT AN ADDITIONAL 1-2". TEMPS WILL BE VERY TRICKY TODAY
OWING TO DIFFICULTY TIMING THE PASSAGE OF THE FRONT...BUT AREAS
NORTH OF RUTLAND/WINDSOR COUNTIES WILL LIKELY REALIZE MAX TEMPS
EARLY THIS MORNING IN THE TEENS TO MID 20S...SLOWLY FALLING INTO
THE SINGLE DIGITS BY THIS AFTERNOON. FOR RUTLAND/WINDSOR...TEMPS
REMAIN STEADY OR CLIMB A BIT INTO THE UPPER 20S TO LOWER 30S BEFORE
DROPPING BEHIND THE FRONT THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
AS OF 415 AM EST MONDAY...DRIER AIR BEGINS TO MOVE IN TONIGHT AS
SURFACE HIGH PRESSURE BUILDS INTO THE REGION ALONG WITH STRONG
COLD AIR ADVECTION ON NORTHERLY FLOW. TOUGH TO TELL HOW MUCH
CLEARING WE`LL SEE AS AN UPPER TROUGH REMAINS OVER THE NORTHEAST
AND THERE`S LOTS OF CLOUD COVER UPSTREAM...BUT THINK WE WILL SEE
SOME BREAKS AND WILL HEDGE TOWARDS PARTLY CLOUDY. THE RETURN OF
ABNORMALLY COLD TEMPERATURES BEGINS TONIGHT THOUGH WHICH WILL
REMAIN ACROSS THE REGION THROUGH MUCH OF THE WEEK. EXPECT LOWS TO
RANGE FROM ZERO TO 15 BELOW TONIGHT...AND WHILE WINDS WILL BE
RATHER LIGHT (4-8 MPH)...THEY`LL BE STRONG ENOUGH TO PRODUCE WIND
CHILLS ACROSS THE MAJORITY OF THE AREA ON THE ORDER OF 20-30 DEGREES
BELOW ZERO. AN ADVISORY HAS BEEN POSTED THROUGH MID-DAY TUESDAY.
FOR THE REMAINDER OF THE SHORT TERM PERIOD PARTLY CLOUDY AND COLD
WILL BE THE RULE AS AFOREMENTIONED SURFACE HIGH SLOWLY SHIFTS
OVER THE REGION AND A BROAD UPPER TROUGH REMAINS ALOFT. HIGH
TEMPS WILL STRUGGLE BOTH TUESDAY AND WEDNESDAY TO GET ABOVE
ZERO...BUT LIKELY WILL BY JUST A FEW DEGREES ACROSS THE
NORTH...AND 5-10 ABOVE SOUTH. WE`LL LIKELY HAVE A REPEAT OF
DANGEROUSLY COLD WIND CHILLS TUESDAY NIGHT AS WELL AS TEMPS DROP
A FEW DEGREES COLDER THAN MONDAY NIGHT AND WINDS REMAIN ABOUT
5-10 MPH OUT OF THE NORTHWEST. I ENVISION ANOTHER ADVISORY BEING
NEEDED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 450 AM EST MONDAY...ECMWF AND GFS MODELS SHOW VERY COLD
ARCTIC AIR WILL BE ENTRENCHED OVER THE REGION FROM WEDNESDAY NIGHT
THROUGH EARLY FRIDAY AS RIDGE OF HIGH PRESSURE WILL BE OVER THE
REGION. EXPECTING LOW TEMPERATURES WEDNESDAY NIGHT AND THURSDAY
NIGHT TO BE BELOW ZERO ACROSS THE REGION...WITH HIGHS ON THURSDAY
ONLY ZERO TO 10 ABOVE ZERO. THE RIDGE OF HIGH PRESSURE MOVES SOUTH
OF THE REGION DURING THE DAY ON FRIDAY. THIS ALLOWS SOUTHERLY
SURFACE WINDS TO DEVELOP OVER THE REGION WITH HIGHS MAINLY 10 TO
15 ABOVE ZERO ON FRIDAY...AND LOW TEMPERATURES FRIDAY NIGHT
REMAINING ABOVE ZERO. ECMWF AND GFS MODELS HINTING AT SOME LAKE
EFFECT SNOW SHOWERS POSSIBLE ACROSS THE SAINT LAWRENCE VALLEY IN
NORTHERN NEW YORK DURING THE DAY ON FRIDAY...SO HAVE SLIGHT CHANCE
POPS FOR SNOW SHOWERS IN THE SAINT LAWRENCE VALLEY ON FRIDAY.
EXPECTING A CHANCE OF SNOW SHOWERS ON SATURDAY DUE TO WARM AIR
ADVECTION ACROSS THE REGION AHEAD OF ANOTHER ARCTIC COLD FRONT
MOVING SOUTHEAST FROM CANADA. ECMWF AND GFS MODELS HOWEVER ARE
SHOWING SOME TIMING DIFFERENCES WITH THE COLD FRONT...WITH THE
ECMWF MODEL FASTER THAN THE GFS MODEL. THE ECMWF MODEL HAS THIS
ARCTIC FRONT EAST OF THE REGION BY EARLY SATURDAY EVENING...WHILE
THE GFS MODEL STILL HAS THIS ARCTIC COLD FRONT IN CANADA
APPROACHING THE SAINT LAWRENCE VALLEY EARLY SATURDAY NIGHT. ECMWF
MODEL SUGGESTS A DRIER FORECAST FOR SATURDAY NIGHT...WHILE THE GFS
MODEL KEEPS IN A CHANCE FOR SOME SNOW SHOWERS. WILL STAY WITH
PREVIOUS CONTINUITY AND KEEP A CHANCE OF SNOW SHOWERS IN THE
FORECAST FOR SATURDAY NIGHT. ECMWF AND GFS MODELS ALSO SHOW A
CHANCE FOR SNOW SHOWERS ON SUNDAY...BUT HAVE DIFFERENT SOLUTIONS.
THE GFS MODEL DEVELOPS A LOW OFF THE SOUTHERN NEW ENGLAND COAST ON
SATURDAY...WHILE THE ECMWF MODEL HAS A LOW TRACKING EAST FROM THE
GREAT LAKES ON SUNDAY. ANYWAY...BOTH MODELS SUGGESTING A CHANCE OF
SNOW SHOWERS ON SUNDAY...BUT DIFFER ON THEIR RESPECTIVE SOLUTIONS.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
THROUGH 12Z TUESDAY...AN ARCTIC COLD FRONT WILL MOVE SOUTH
THROUGH VERMONT AND NORTHERN NEW YORK TODAY WITH AREAS OF IFR IN
SNOW SHOWERS THIS MORNING. THE ARCTIC COLD FRONT WILL BE SOUTH OF
THE REGION BY 18Z MONDAY. EXPECTING MAINLY VFR CONDITIONS AFTER
18Z MONDAY...BUT WILL LIKELY SEE SOME AREAS OF MVFR CEILINGS WITH
LIGHT SNOW OVER THE ADIRONDACKS AND GREEN MOUNTAINS CONTINUING
AFTER 18Z MONDAY.
OUTLOOK 12Z TUESDAY THROUGH FRIDAY...
12Z TUESDAY THRU FRIDAY...MAINLY VFR WITH HIGH PRESSURE AND VERY
COLD TEMPERATURES.
&&
.EQUIPMENT...
AS OF 415 AM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK REMAINS OUT OF SERVICE DUE TO A FAILED POWER
SUPPLY. PARTS ARE ON ORDER TO REPAIR THE PROBLEM BUT IT WILL
LIKELY BE OUT OF SERVICE THROUGH AT LEAST TUESDAY JANUARY 21.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR VTZ001>004-006>008-010-016>019.
NY...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM EST
TUESDAY FOR NYZ026>031-034-087.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...WGH
AVIATION...WGH/KGM
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
627 AM CST MON JAN 20 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 411 AM CST MON JAN 20 2014
ON THE MAP EARLY THIS MORNING...AS WELL AS EVIDENT ON THE OVERNIGHT
SATELLITE IMAGERY...IS BACKDOOR ARCTIC BOUNDARY EXTENDING FROM WEAK
LOW PRESSURE IN CENTRAL NORTH DAKOTA TO CENTRAL MINNESOTA. ELONGATED
UPPER WAVE WITH ONE CENTER IN NORTHERN WISCONSIN...A SECOND IN NORTH
DAKOTA...AND MOST IMPORTANTLY A THIRD IN SOUTHERN SASKATCHEWAN.
EXTREMELY COMPLEX FORECAST IN THE SHORT TERM DEALING WITH CHANGES IN
TEMPERATURE...POP DISTRIBUTION...AND WIND ASSOCIATED WITH THE
BOUNDARY PASSAGE. TIMING OF BOUNDARY HAS COME INTO A CLEARER FOCUS
ON 00Z/06Z SOLUTION SETS...BACKING TO HURON/SIOUX FALLS/SPENCER LINE
BEHIND WEAK SURFACE WAVE MOVING INTO CENTRAL IOWA BY 18Z...THEN
CONTINUING A QUICKENING PACE SOUTHWARD THROUGH THE REST OF THE
AFTERNOON. LOCATION IS IMPORTANT AS MOST OF THE PRECIPITATION WILL
BE POST FRONTAL...AND TO CONSIDER LOCATIONS WITH GREATER POTENTIAL
TO WARM AHEAD OF THE BOUNDARY.
WIND IS THE FIRST FEATURE OF THE SYSTEM TODAY. WILL BE FAIRLY WELL
MIXED ALONG AND AHEAD OF THE BOUNDARY...AND WILL SEE 925 HPA WINDS
INCREASE TO 30 TO 40 KNOTS DURING THE LATER MORNING AS SYSTEM
APPROACHES. LOOKS LIKE CLASSIC MISSOURI VALLEY TRACK TO STRONGEST
OFF SURFACE WIND CORE FROM 925 TO 850 HPA. WILL ALSO BE WATCHING
MASSIVE PRESSURE RISES OF 8-12 HPA/3H ASSOCIATED WITH THE FINAL WAVE
WHICH TIMES OUT TO DIG ACROSS THE AREA EARLY TO MID AFTERNOON. THIS
COULD PROVIDE A STRONG PULSE TO WINDS WHICH WILL WORK THROUGH THE
AREA. HAVE ISSUED A WIND ADVISORY FOR AREAS WEST OF THE JAMES
RIVER...THEN INTO THE LOWER MISSOURI VALLEY FROM LATE MORNING
THROUGH THE AFTERNOON. MAY END UP HAVING TO ADD COUPLE MORE TIERS
OF COUNTIES EASTWARD INTO THE WIND ADVISORY IF TRENDS IN 06Z NAM
WIND/PRESSURE TENDENCY CONTINUE TO BECOME EVIDENT. NO REASON TO
DOUBT WITH 9-10 HPA/3H RISES ON CURRENT ANALYSIS.
HAVE MAINTAINED THE HIGH POPS IN THE FORECAST ADVERTISED OVER THE
PAST COUPLE OF DAYS...BUT DID SLOW UP THE ONSET SOME EARLY THIS
MORNING. SOUNDINGS INDICATE THAT WILL GET A STRONG COOLING AND
SATURATION IN THE DENDRITIC ZONE. LIFT PROVIDED PRIMARILY WITH THE
ADVANCE OF THE COLD AIR...A SHALLOW FORCING. COULD BE A LITTLE
BROADENING OF THE PRECIP AREA THIS AFTERNOON AS THE DEEPER MOISTURE
AND UPPER LEVEL FORCING INCREASES WITH PASSAGE OF THIRD UPPER WAVE
ENERGY...BUT FOR THE MOST PART THE FLAVOR OF THE SNOW DISTRIBUTION
IS TIED TO THE 925-850 HPA FRONTOGENESIS. WILL LIKELY END UP WITH A
BAND OF A INCH OR A LITTLE MORE FROM PARTS OF EAST CENTRAL SD INTO
NW IA...TAPERING TO LESS THAN A HALF INCH WEST OF THE JAMES RIVER.
AT THIS TIME...NOT EXPECTING SIGNIFICANT PROBLEMS WITH BLOWING SNOW
AS STRONGEST WINDS WILL LIKELY OCCUR IN AREAS THAT HAVE MELTED TO
SNOW FREE PRIOR TO SNOWFALL TODAY...AND GREATER AMOUNTS WILL OCCUR
WITH SOMEWHAT WEAKER WINDS.
CURRENTLY...TEMPERATURES FOR THE MOST PART HAVE BEEN RUNNING WARMER
THAN GUIDANCE WITH A PERSISTENT MODEST WEST NORTHWEST WIND AHEAD OF
THE ADVANCING BOUNDARY ALONG WITH HIGH CLOUDS. WILL HAVE THESE
CLOUDS THIN SOMEWHAT LATE IN CURRENT NIGHT...AND IF WINDS DROP A BIT
WILL KNOCK TEMPS DOWN. HIGHS UP NORTH ARE CERTAINLY GOING TO BE
EARLY IN THE DAY AND THEN SEE A DRASTIC PLUNGE BEHIND THE BACKDOOR
BOUNDARY. COMPLEX FORECAST AS THERE IS SOME QUESTION AS TO HOW WARM
IT MAY GET AHEAD OF THE BACKDOOR PUSH THROUGH THE MISSOURI VALLEY
TODAY...WITH WARMEST SOLUTION IN RAP SUGGESTING SOME LOWER TO MID
40S ARE AN EASY REACH. MADE SOME DRASTIC CHANGES TO THE TEMP
FORECAST FOR TODAY...WARMING UP SOME LOCATIONS 7-10 DEGREES FROM
EARLIER FORECAST...AND EVEN UP A HALF DOZEN IN THE NORTH IN PLACES
WITH HOPES THAT DO NOT GET TOO MUCH OF A LATE NIGHT DIP.
FINALLY...WIND CHILLS WILL PLUMMET TO 20 BELOW TO 30 BELOW ZERO
TONIGHT FROM JUST WEST OF THE INTERSTATE 29 CORRIDOR IN SD TO JUST
EAST OF IT AROUND KSUX. WHILE REALIZE THAT NORTHERN AREAS WILL KICK
INTO CRITERIA A BIT SOONER AND SOUTHERN LOCATIONS LATER...BUT
STARTED ALL LOCATIONS UP AT THE SAME TIME FOR SIMPLICITY. DID
THROUGH DROP OFF THE WESTERN HALF LATE AT NIGHT GIVEN THE SPRAWLING
SURFACE RIDGE AND LIKELIHOOD OF LIGHT WINDS...COMPARED TO LOCATIONS
FURTHER EAST IN SW MN AND NW IA. EVEN WITHOUT WINDS...WILL SEE SOME
LOWS WELL INTO THE TEENS BELOW ZERO...BUT ALSO SHOULD START TO GET
SOME MODIFICATION TO READINGS LATER IN THE WEST WITH WEAK SOUTHERLY
FLOW AND THICKER HIGH CLOUDS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 411 AM CST MON JAN 20 2014
A VERY COLD START TO THE MORNING ON TUESDAY AS COLD HIGH PRESSURE
GRADUALLY DRIFTS EASTWARD. SOME WARMING WILL TRY TO DEVELOP BUT WILL
LIKELY BE LIMITED TO AREAS ALONG AND WEST OF THE JAMES RIVER VALLEY
AS THE STUBBORN COLD HIGH PRESSURE WILL LIMIT THE PUSH OF WARMER
AIR. HIGHS WILL LIKELY VARY FROM ABOUT THE MID 30S NEAR GREGORY SD
TO NEAR 10 ABOVE IN SOUTHWEST MINNESOTA.
AS LOW PRESSURE ALOFT DROPS INTO THE NORTHERN GREAT LAKES TUESDAY
NIGHT INTO WEDNESDAY WINDS WILL TURN FROM THE SOUTHWEST TO THE WEST
AND NORTHWEST OVERNIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING
TOO FAR OVERNIGHT BUT WILL ALSO LIMIT THE RISE ON WEDNESDAY AS THE
COLDER AIR SURGES SOUTH...ESPECIALLY IN THE AFTERNOON. THERE WILL BE
A SMALL THREAT FOR LIGHT SNOW AS WARM ADVECTION DEVELOPS TUESDAY
NIGHT BUT DRY AIR SHOULD LIMIT THOSE CHANCES TO MAINLY SOUTHWEST
MINNESOTA. LOWS ON TUESDAY NIGHT NEAR ZERO IN SOUTHWEST MINNESOTA TO
NEAR 20 IN SOUTH CENTRAL SD. TEMPERATURES ON WEDNESDAY SHOULD CLIMB
INTO THE MID TO UPPER 20S ON WEDNESDAY DOWN THE MISSOURI RIVER
CORRIDOR BUT ONLY IN TO THE SINGLE DIGITS IN THE NORTHERN CWA AS THE
COLDER AIR WORKS SOUTH. IN FACT...MOST LOCATIONS SHOULD SEE FALLING
TEMPERATURES IN THE AFTERNOON.
WEDNESDAY NIGHT INTO THURSDAY LOOKS PRETTY DARN COLD AS A 1050 MB
HIGH PRESSURE BUILDS INTO THE AREA. THIS SHOULD ALLOW TEMPERATURES
TO FALL WELL INTO THE MID TEENS BELOW ZERO. AND WITH WEAK MIXING ON
THURSDAY HIGHS WILL ONLY REACH THE SINGLE DIGITS IN MOST SPOTS WITH
15 TO 20 WEST OF THE JAMES RIVER VALLEY.
IN THE OUTER PERIODS...FRI/SUN...A FAIRLY STRONG NORTH TO NORTHWEST
FLOW ALOFT REESTABLISHES WHICH KEEPS THE AREA WITHIN A VARIABLE
THERMAL REGIME. WILL NOT LEAN HARD IN ANY ONE DIRECTION DURING THIS
TIME AS THE THERMAL GRADIENT IS LARGE ENOUGH ACROSS THE AREA THAT
THE TIMING AND LOCATION OF ANY WAVE WILL MAKE POTENTIALLY VERY LARGE
DIFFERENCES. OVERALL WILL LEAN TOWARDS SLIGHTLY ABOVE NORMAL
TEMPERATURES ON FRIDAY AND SATURDAY AND BELOW NORMAL TEMPERATURES BY
SUNDAY. A SMALL CHANCE FOR LIGHT SNOW SATURDAY BUT THIS LIKE THE
TEMPERATURES IS A BIT VARIABLE SO NO BIG CHANCES NOR ANY THREAT FOR
ANY MAJOR SYSTEMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 614 AM CST MON JAN 20 2014
VERY COMPLEX AVIATION CONCERNS OVER THE NEXT 12 HOURS WITH CLIPPER
SYSTEM MOVING FROM NORTHERN SD INTO CENTRAL IA...AND ARCTIC
BOUNDARY SLIDING SOUTHWARD THROUGH THE AREA. LIFR STRATUS WILL BUILD
SOUTHWARD BEHIND THE ARCTIC FRONT...AND THERE WILL ALSO BE AN
AREA OF SNOWFALL WORKING IN BEHIND THE BOUNDARY THAT MAY REDUCE
VISIBILITY TO 1 TO 2 MILES ON THE AVERAGE...PERHAPS BRIEFLY 1/2 MILE...
FOR A 2-3 HOUR PERIOD AT EACH SITE. SURFACE WINDS GUSTS WILL ALSO
EXCEED 35 KNOTS FOR KHON/KFSD AND KSUX BY LATE MORNING AND
CONTINUE THROUGH THE AFTERNOON...AND EVEN EARLY EVENING AT KSUX.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 10 AM THIS MORNING TO 5 PM CST THIS AFTERNOON
FOR SDZ050-057-058-063-064-068-069.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR SDZ039-040-055-056-062-067.
MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR MNZ071-097-098.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR MNZ072-080-081-089-090.
IA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR IAZ001-012.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR IAZ002-003-013-014-021-022-032.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
412 AM CST MON JAN 20 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 411 AM CST MON JAN 20 2014
ON THE MAP EARLY THIS MORNING...AS WELL AS EVIDENT ON THE OVERNIGHT
SATELLITE IMAGERY...IS BACKDOOR ARCTIC BOUNDARY EXTENDING FROM WEAK
LOW PRESSURE IN CENTRAL NORTH DAKOTA TO CENTRAL MINNESOTA. ELONGATED
UPPER WAVE WITH ONE CENTER IN NORTHERN WISCONSIN...A SECOND IN NORTH
DAKOTA...AND MOST IMPORTANTLY A THIRD IN SOUTHERN SASKATCHEWAN.
EXTREMELY COMPLEX FORECAST IN THE SHORT TERM DEALING WITH CHANGES IN
TEMPERATURE...POP DISTRIBUTION...AND WIND ASSOSICATED WITH THE
BOUNDARY PASSAGE. TIMING OF BOUNDARY HAS COME INTO A CLEARER FOCUS
ON 00Z/06Z SOLUTION SETS...BACKING TO HURON/SIOUX FALLS/SPENCER LINE
BEHIND WEAK SURFACE WAVE MOVING INTO CENTRAL IOWA BY 18Z...THEN
CONTINUING A QUICKENING PACE SOUTHWARD THROUGH THE REST OF THE
AFTERNOON. LOCATION IS IMPORTANT AS MOST OF THE PRECIPITATION WILL
BE POST FRONTAL...AND TO CONSIDER LOCATIONS WITH GREATER POTENTIAL
TO WARM AHEAD OF THE BOUNDARY.
WIND IS THE FIRST FEATURE OF THE SYSTEM TODAY. WILL BE FAIRLY WELL
MIXED ALONG AND AHEAD OF THE BOUNDARY...AND WILL SEE 925 HPA WINDS
INCREASE TO 30 TO 40 KNOTS DURING THE LATER MORNING AS SYSTEM
APPROACHES. LOOKS LIKE CLASSIC MISSOURI VALLEY TRACK TO STRONGEST
OFF SURFACE WIND CORE FROM 925 TO 850 HPA. WILL ALSO BE WATCHING
MASSIVE PRESSURE RISES OF 8-12 HPA/3H ASSOCIATED WITH THE FINAL WAVE
WHICH TIMES OUT TO DIG ACROSS THE AREA EARLY TO MID AFTERNOON. THIS
COULD PROVIDE A STRONG PULSE TO WINDS WHICH WILL WORK THROUGH THE
AREA. HAVE ISSUED A WIND ADVISORY FOR AREAS WEST OF THE JAMES
RIVER...THEN INTO THE LOWER MISSOURI VALLEY FROM LATE MORNING
THROUGH THE AFTERNOON. MAY END UP HAVING TO ADD COUPLE MORE TIERS
OF COUNTIES EASTWARD INTO THE WIND ADVISORY IF TRENDS IN 06Z NAM
WIND/PRESSURE TENDENCY CONTINUE TO BECOME EVIDENT. NO REASON TO
DOUBT WITH 9-10 HPA/3H RISES ON CURRENT ANALYSIS.
HAVE MAINTAINED THE HIGH POPS IN THE FORECAST ADVERTISED OVER THE
PAST COUPLE OF DAYS...BUT DID SLOW UP THE ONSET SOME EARLY THIS
MORNING. SOUNDINGS INDICATE THAT WILL GET A STRONG COOLING AND
SATURATION IN THE DENDRITIC ZONE. LIFT PROVIDED PRIMARILY WITH THE
ADVANCE OF THE COLD AIR...A SHALLOW FORCING. COULD BE A LITTLE
BROADENING OF THE PRECIP AREA THIS AFTERNOON AS THE DEEPER MOISTURE
AND UPPER LEVEL FORCING INCREASES WITH PASSAGE OF THIRD UPPER WAVE
ENERGY...BUT FOR THE MOST PART THE FLAVOR OF THE SNOW DISTRIBUTION
IS TIED TO THE 925-850 HPA FRONTOGENESIS. WILL LIKELY END UP WITH A
BAND OF A INCH OR A LITTLE MORE FROM PARTS OF EAST CENTRAL SD INTO
NW IA...TAPERING TO LESS THAN A HALF INCH WEST OF THE JAMES RIVER.
AT THIS TIME...NOT EXPECTING SIGNIFICANT PROBLEMS WITH BLOWING SNOW
AS STRONGEST WINDS WILL LIKELY OCCUR IN AREAS THAT HAVE MELTED TO
SNOW FREE PRIOR TO SNOWFALL TODAY...AND GREATER AMOUNTS WILL OCCUR
WITH SOMEWHAT WEAKER WINDS.
CURRENTLY...TEMPERATURES FOR THE MOST PART HAVE BEEN RUNNING WARMER
THAN GUIDANCE WITH A PERSISTENT MODEST WEST NORTHWEST WIND AHEAD OF
THE ADVANCING BOUNDARY ALONG WITH HIGH CLOUDS. WILL HAVE THESE
CLOUDS THIN SOMEWHAT LATE IN CURRENT NIGHT...AND IF WINDS DROP A BIT
WILL KNOCK TEMPS DOWN. HIGHS UP NORTH ARE CERTAINLY GOING TO BE
EARLY IN THE DAY AND THEN SEE A DRASTIC PLUNGE BEHIND THE BACKDOOR
BOUNDARY. COMPLEX FORECAST AS THERE IS SOME QUESTION AS TO HOW WARM
IT MAY GET AHEAD OF THE BACKDOOR PUSH THROUGH THE MISSOURI VALLEY
TODAY...WITH WARMEST SOLUTION IN RAP SUGGESTING SOME LOWER TO MID
40S ARE AN EASY REACH. MADE SOME DRASTIC CHANGES TO THE TEMP
FORECAST FOR TODAY...WARMING UP SOME LOCATIONS 7-10 DEGREES FROM
EARLIER FORECAST...AND EVEN UP A HALF DOZEN IN THE NORTH IN PLACES
WITH HOPES THAT DO NOT GET TOO MUCH OF A LATE NIGHT DIP.
FINALLY...WIND CHILLS WILL PLUMMET TO 20 BELOW TO 30 BELOW ZERO
TONIGHT FROM JUST WEST OF THE INTERSTATE 29 CORRIDOR IN SD TO JUST
EAST OF IT AROUND KSUX. WHILE REALIZE THAT NORTHERN AREAS WILL KICK
INTO CRITERIA A BIT SOONER AND SOUTHERN LOCATIONS LATER...BUT
STARTED ALL LOCATIONS UP AT THE SAME TIME FOR SIMPLICITY. DID
THROUGH DROP OFF THE WESTERN HALF LATE AT NIGHT GIVEN THE SPRAWLING
SURFACE RIDGE AND LIKELIHOOD OF LIGHT WINDS...COMPARED TO LOCATIONS
FURTHER EAST IN SW MN AND NW IA. EVEN WITHOUT WINDS...WILL SEE SOME
LOWS WELL INTO THE TEENS BELOW ZERO...BUT ALSO SHOULD START TO GET
SOME MODIFICATION TO READINGS LATER IN THE WEST WITH WEAK SOUTHERLY
FLOW AND THICKER HIGH CLOUDS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 411 AM CST MON JAN 20 2014
A VERY COLD START TO THE MORNING ON TUESDAY AS COLD HIGH PRESSURE
GRADUALLY DRIFTS EASTWARD. SOME WARMING WILL TRY TO DEVELOP BUT WILL
LIKELY BE LIMITED TO AREAS ALONG AND WEST OF THE JAMES RIVER VALLEY
AS THE STUBBORN COLD HIGH PRESSURE WILL LIMIT THE PUSH OF WARMER
AIR. HIGHS WILL LIKELY VARY FROM ABOUT THE MID 30S NEAR GREGORY SD
TO NEAR 10 ABOVE IN SOUTHWEST MINNESOTA.
AS LOW PRESSURE ALOFT DROPS INTO THE NORTHERN GREAT LAKES TUESDAY
NIGHT INTO WEDNESDAY WINDS WILL TURN FROM THE SOUTHWEST TO THE WEST
AND NORTHWEST OVERNIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING
TOO FAR OVERNIGHT BUT WILL ALSO LIMIT THE RISE ON WEDNESDAY AS THE
COLDER AIR SURGES SOUTH...ESPECIALLY IN THE AFTERNOON. THERE WILL BE
A SMALL THREAT FOR LIGHT SNOW AS WARM ADVECTION DEVELOPS TUESDAY
NIGHT BUT DRY AIR SHOULD LIMIT THOSE CHANCES TO MAINLY SOUTHWEST
MINNESOTA. LOWS ON TUESDAY NIGHT NEAR ZERO IN SOUTHWEST MINNESOTA TO
NEAR 20 IN SOUTH CENTRAL SD. TEMPERATURES ON WEDNESDAY SHOULD CLIMB
INTO THE MID TO UPPER 20S ON WEDNESDAY DOWN THE MISSOURI RIVER
CORRIDOR BUT ONLY IN TO THE SINGLE DIGITS IN THE NORTHERN CWA AS THE
COLDER AIR WORKS SOUTH. IN FACT...MOST LOCATIONS SHOULD SEE FALLING
TEMPERATURES IN THE AFTERNOON.
WEDNESDAY NIGHT INTO THURSDAY LOOKS PRETTY DARN COLD AS A 1050 MB
HIGH PRESSURE BUILDS INTO THE AREA. THIS SHOULD ALLOW TEMPERATURES
TO FALL WELL INTO THE MID TEENS BELOW ZERO. AND WITH WEAK MIXING ON
THURSDAY HIGHS WILL ONLY REACH THE SINGLE DIGITS IN MOST SPOTS WITH
15 TO 20 WEST OF THE JAMES RIVER VALLEY.
IN THE OUTER PERIODS...FRI/SUN...A FAIRLY STRONG NORTH TO NORTHWEST
FLOW ALOFT REESTABLISHES WHICH KEEPS THE AREA WITHIN A VARIABLE
THERMAL REGIME. WILL NOT LEAN HARD IN ANY ONE DIRECTION DURING THIS
TIME AS THE THERMAL GRADIENT IS LARGE ENOUGH ACROSS THE AREA THAT
THE TIMING AND LOCATION OF ANY WAVE WILL MAKE POTENTIALLY VERY LARGE
DIFFERENCES. OVERALL WILL LEAN TOWARDS SLIGHTLY ABOVE NORMAL
TEMPERATURES ON FRIDAY AND SATURDAY AND BELOW NORMAL TEMPERATURES BY
SUNDAY. A SMALL CHANCE FOR LIGHT SNOW SATURDAY BUT THIS LIKE THE
TEMPERATURES IS A BIT VARIABLE SO NO BIG CHANCES NOR ANY THREAT FOR
ANY MAJOR SYSTEMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1027 PM CST SUN JAN 19 2014
STRATUS WILL BEGIN TO OVERSPREAD THE AREA FROM THE
NORTH AFTER 09Z...WITH LIGHT SNOW DEVELOPING ACROSS THE AREA AFTER
15Z ON MONDAY...CAUSING REDUCED VISIBILITIES. NORTHWEST WINDS WILL
AGAIN PICK UP THROUGH THE DAY...GUSTING TO AROUND 25 KTS DURING
THE AFTERNOON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 10 AM THIS MORNING TO 5 PM CST THIS AFTERNOON
FOR SDZ050-057-058-063-064-068-069.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR SDZ039-040-055-056-062-067.
MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR MNZ071-097-098.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR MNZ072-080-081-089-090.
IA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR IAZ001-012.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR IAZ002-003-013-014-021-022-032.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...JM
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
323 PM MST MON JAN 20 2014
.SHORT TERM...WINDS STILL GUSTY ACROSS NORTHEAST CORNER...THOUGH
SHOWING SOME SIGNS OF DECREASING. EARLIER A GUST TO 55 MPH WAS
REPORTED AT HOLYOKE AT 155 PM. THERE WAS ALSO SOME BLOWING DUST
IN THE AREA. FURTHER WEST...WINDS MUCH WEAKER. MODELS CONTINUE TO
SHOW GRADIENT WEAKENING ACROSS NORTHEAST COLORADO BY 00Z WITH
WINDS DECREASING. WILL CONTINUE THIS TREND THROUGH THE EVENING.
OVERNIGHT...NORTHWEST FLOW ALOFT INCREASES BEHIND EXITING UPPER
TROUGH. LATEST RAP SPATIAL CROSS SECTIONS SHOW CROSS MOUNTAIN FLOW
INCREASING TO AROUND 35 KTS AT MOUNTAIN TOP. WEAK SUBSIDENCE
OVERHEAD WILL HELP INCREASE DOWNWARD MOTION AND ALLOW FOR WINDS TO
INCREASE ACROSS THE HIGHER MOUNTAINS AND ALONG THE FOOTHILLS AFTER
MIDNIGHT. SOME GUSTS AROUND 40 MPH A POSSIBILITY. CLEARING SKIES
AND LESS WIND WILL ALLOW FOR COLDER OVERNIGHT LOWS ACROSS THE
PLAINS WITH READINGS MAINLY IN THE 20S...EXCEPT TEENS LOW LYING
AREAS AND FAR NORTHEAST CORNER. ON TUESDAY...UPPER RIDGE BUILDS
CONTINUES TO BUILD ACROSS THE GREAT BASIN AND INTO COLORADO.
MODERATE NORTHWEST FLOW ALOFT AND WEAK SUBSIDENCE WILL KEEP GUSTY
WINDS GOING ACROSS THE HIGHER MOUNTAINS AND ALONG FOOTHILLS. THERE
WILL BE SUFFICIENT MIXING ACROSS THE PLAINS FOR GUSTY WINDS TO
DEVELOP...MAINLY ALONG THE NORTHERN BORDER AND FAR NORTHEAST
PLAINS. GRADIENT MUCH WEAKER THAT TODAY...SO GUSTS WON`T BE AS
STRONG. WARM AIR ADVECTION FROM THE WEST AND WEAK DOWNSLOPE WINDS
WILL ALLOW TEMPERATURES TO RISE INTO THE 50S ACROSS THE PLAINS.
.LONG TERM...NW FLOW ALOFT WILL CONTINUE ON WED IN ADVANCE OF A
WEAK UPPER LVL TROUGH. MEANWHILE A COLD FRONT WILL MOVE INTO NERN
CO BY WED AFTN WHICH IS A BIT FASTER THAN WHAT WAS SHOWN
YESTERDAY. THUS WILL KEEP HIGHS IN THE 40S OVER NERN CO. FOR WED
NIGHT INTO EARLY THU A WK UPPER LEVEL TROUGH WILL MOVE ACROSS WITH
MOST OF THE ENERGY STAYING WEST OF THE AREA AS ONLY SOME WK MID
LVL QG ASCENT IS SHOWN. IN ADDITION AS COLD SFC HIGH PRESSURE
BUILDS ACROSS THE NRN AND CENTRAL PLAINS THERE WILL BE SOME LOW
LVL UPSLOPE WED NIGHT INTO EARLY THU MORNING. CURRENT CROSS-
SECTIONS SHOW ENOUGH MOISTURE FOR SOME LIGHT SNOW EAST OF THE
DIVIDE AND ACROSS PORTIONS OF NERN CO. HIGHS ON THU WILL BE MUCH
COLDER WITH READINGS IN THE 25 TO 30 DEGREE RANGE OVER THE PLAINS.
BY THU AFTN MUCH DRIER AIR WILL SPREAD ACROSS NRN CO WITH NO LOW
LVL UPSLOPE AS THE SFC HIGH QUICKLY BUILDS EAST AND SE OF THE
AREA. THUS SNOW CHANCES SHOULD END BY MIDDAY OVER MOST OF THE CWA.
FOR THU NIGHT AND FRI RATHER DRY NNW FLOW WILL BE OVER THE AREA SO
WILL NOT MENTION ANY PCPN. TEMPS ON FRI SHOULD QUICKLY REBOUND
WITH READINGS IN THE 45 TO 50 DEGREE RANGE ACROSS NERN CO.
FOR THE WEEKEND THE FLOW ALOFT WILL REMAIN NWLY WITH NOT MUCH
MOISTURE SO WILL KEEP A DRY FCST IN PLACE. GUSTY WINDS WILL OCCUR
AT TIMES OVER THE HIGHER TERRAIN AND ACROSS THE PLAINS NEAR THE
WY...NE BORDER. HIGHS WILL LIKELY BE AT LEAST 10 DEGREES ABV NORMAL
ACROSS NERN CO BASED ON LATEST DATA.
&&
.AVIATION...WINDS HAVE SHIFTED BACK TO THE NORTH AS A WEAK SURGE
MOVED ACROSS THE AREA. SPEEDS ARE NOW BEGINNING TO DECREASE.
SHOULD SEE WINDS SHIFT CLOCKWISE TO THE EAST AND SOUTHEAST BY
02Z. DRAINAGE FLOW TO THEN DEVELOP WITH SOUTHERLY WINDS AT KDEN
AND KAPA AND WESTERLY AT KBJC. SOME GUSTS TO 15 KTS POSSIBLE AT
KBJC OVERNIGHT. WINDS TO SHIFT TO THE WEST NORTHWEST BY 15Z WITH
SPEEDS AROUND 8 KTS. VFR TO CONTINUE WITH UNLIMITED CEILINGS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RPK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GOODLAND KS
213 PM MST MON JAN 20 2014
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 208 PM MST MON JAN 20 2014
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW BROAD UPPER
LEVEL TROUGH OVER THE EASTERN US...WITH AMPLIFIED RIDGE ACROSS THE
WESTERN US. A SHORTWAVE TROUGH CURRENTLY OVER THE EASTERN HALF OF
NE/KS WITH STRONG SUBSIDENCE APPARENT BY DRY LAYER ON WV IMAGERY AND
PV HEIGHT ANOMALY OVER SOUTHERN NE/NORTHERN KS...IS ON THE BACK SIDE
OF THE SHORTWAVE TROUGH AXIS AND OVER OUR CWA. AT THE SURFACE A COLD
FRONT IS OVER NORTHCENTRAL NEBRASKA.
REGARDING CURRENT WIND ADVISORY...LOCATIONS ACROSS THE CWA ARE
CURRENTLY HITTING CRITERIA WITH GUSTS 39-40KT REPORTED. WHILE IT IS
NOT WIDESPREAD YET...UPSTREAM OBS ARE WELL OVER CRITERIA...AND AN
AREA OF BLOWING DUST ORIGINATING FROM THE SOUTHERN NEBRASKA
PANHANDLE IS APPARENT ON SATELLITE. WE STILL HAVE ENOUGH TIME WITH
PEAK DAYTIME MIXING THAT I AM COMFORTABLE LETTING THE ADVISORY
CONTINUE THROUGH 00Z AS IS. I DO HAVE CONCERNS ABOUT NEAR RFW
CRITERIA BEING MET...HOWEVER SHORT RANGE GUIDANCE IS INDICATING
HIGHER TD VALUES ADVECTING FROM THE NE AHEAD OF COLD FRONT...SO I
WILL MONITOR SINCE IT LOOKS LIKE OUR RH WILL PROBABLY HOLD STEADY OR
INCREASE SLIGHTLY.
COLD FRONT MOVES THROUGH TONIGHT...WITH MUCH COLDER TEMPS ALOFT
THROUGH EARLY TOMORROW MORNING. OVERNIGHT LOWS AT LOCATIONS WHERE
WINDS GO CALM COULD BE AS LOW AS SINGLE DIGITS. THIS COOL DOWN WILL
BE SHORT LIVED AS GOOD WAA ASSOCIATED WITH BUILDING LEE TROUGH
TUESDAY...AND A RETURN TO MILD TEMPS. IT LOOKS LIKE WE SHOULD SEE
BREEZY CONDITIONS TUESDAY...THOUGH THEY SHOULD REMAIN WELL BELOW
ADVISORY CRITERIA. RH VALUES RANGING FROM 13-18 PERCENT ACROSS MUCH
OF THE CWA COULD SUPPORT CRITICAL FIRE CONDITIONS. MIXING HEIGHTS ON
NAM/GFS ARE FAIRLY UNIMPRESSIVE...AND I AM WONDERING WHETHER WE WILL
REALLY SEE 3HR OF RH/WIND CROSSOVER...SO I DECIDED AGAINST ISSUING
ANY FIRE WEATHER HIGHLIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 208 PM MST MON JAN 20 2014
NORTHWEST FLOW CONTINUES THROUGH THURSDAY ACROSS THE CENTRAL PLAINS.
A SURFACE TROUGH WILL SHIFT EAST INTO CENTRAL/EASTERN KANSAS TUESDAY
NIGHT AS HIGH PRESSURE BUILDS INTO THE REGION BEHIND THE TROUGH. AN
ARCTIC FRONT WILL MOVE INTO THE REGION WEDNESDAY AFTERNOON AND
EVENING. HIGH PRESSURE WILL REMAIN OVER THE CENTRAL PLAINS THROUGH
THURSDAY.
SUBSIDENCE WILL KEEP THE FORECAST DRY THROUGH WEDNESDAY. AN ARCTIC
FRONT WILL BRING A CHANCE OF LIGHT SNOW AND FLURRIES TO THE FA
WEDNESDAY NIGHT AND THURSDAY. POPS WILL DECREASE WITH TIME FROM EAST
TO WEST WITH FORCING ASSOCIATED SHORTWAVE ENERGY AND THE ARCTIC
FRONT. THERE IS A NARROW BAND OF ADEQUATE MOISTURE COINCIDENT WITH
THE LIFT THAT WILL BE FAVORABLE FOR SOME LIGHT SNOW BUT IT WILL BE
BRIEF WITH LITTLE CHANCE FOR MUCH ACCUMULATING SNOW, GENERALLY LESS
THAN AN INCH. PLAN TO HAVE CHANCE POPS OVER EASTERN COLORADO WHERE
MOISTURE AND LIFT WILL BE MOST AVAILABLE TO FLURRIES OVER THE
EASTERN HALF OF THE FA. MOISTURE DRIES SIGNIFICANTLY THURSDAY
AFTERNOON SO POPS WILL GO BACK TO NIL.
MIN TEMPERATURES WILL RANGE FROM THE LOWER 20S TUESDAY NIGHT. BEHIND
THE ARCTIC FRONT, TEMPERATURES WILL FALL TO THE SINGLE DIGITS. MAX
TEMPERATURES WEDNESDAY WILL RISE TO THE MID 40S. MAX TEMPERATURES
THURSDAY WILL BE COLDER WITH READINGS IN THE LOWER 20S.
IN THE EXTENDED...(THURSDAY NIGHT THROUGH MONDAY)...NORTHWEST FLOW
PERSISTS THROUGH THIS PART OF THE FORECAST. LACK OF ANY SIGNIFICANT
FORCING AND MOISTURE WILL KEEP DRY CONDITIONS ONGOING THROUGH
MONDAY. MAX TEMPERATURES WILL RANGE FROM THE UPPER 40S TO THE UPPER
50S SUNDAY COOLING DOWN TO THE LOWER TO MID 40S MONDAY. MIN
TEMPERATURES WILL FALL TO THE TEENS THURSDAY NIGHT OTHERWISE MIN
TEMPERATURES WILL BE IN THE MID 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1028 AM MST MON JAN 20 2014
MAIN CONCERN IS WINDS THIS AFTERNOON AND POSSIBILITY OF RESTRICTED
VIS AS A RESULT OF BLOWING DUST. NW WINDS ALREADY COMING UP AT GLD
AND EXPECT THE SAME BY 19Z AT KMCK BASED ON UPSTREAM OBS.
EXPECTING GUSTS TO 40KT AT BOTH TERMINALS THIS AFTERNOON WHICH
COULD PRODUCE BLOWING DUST ACROSS THE REGION. WINDS MAY BE A
LITTLE STRONGER AT KMCK. I AM CURRENTLY NOT CONFIDENT ENOUGH TO
ADD MORE THAN TEMPO VIS 6SM AT EITHER TERMINAL BASED ON PREVIOUS
WIND EVENT WITH SIMILAR WIND VALUES. WILL NEED TO MONITOR. WINDS
SHOULD DIMINISH LATE AFTERNOON/EARLY EVENING WITH LOSS OF DAYTIME
HEATING...AND SHOULD REMAIN 12KT OR LESS THROUGH REMAINING TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON FOR
KSZ001>004-013>016-027>029.
CO...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ090-091.
NE...WIND ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON FOR
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...FS
AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
528 PM EST MON JAN 20 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 520 PM EST MON JAN 20 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT NW FLOW
ALF OVER THE GREAT LKS BTWN CUTOFF UPR LO OVER QUEBEC AND RDG ALONG
THE W COAST. AT THE SFC...ARCTIC HI PRES IS CENTERED OVER SCENTRAL
CANADA. N FLOW OF VERY COLD AIR...WITH 12Z H85 TEMPS AS LO AS -29C
AT PICKLE LAKE AND MOOSONEE IN ONTARIO...ACRS LK SUP IS CAUSING NMRS
WIND PARALLEL BANDS OF LK EFFECT SN THAT ARE AFFECTING DOWNSTREAM
AREAS NEAR THE BIG LAKE DESPITE LARGER SCALE QVECTOR DVGC/SUBSIDENCE
IN THE WAKE OF CLIPPER SHRTWV MOVING THRU LOWER MI AS WELL AS THE
FEED OF VERY DRY LLVL ARCTIC AIR. 12Z INL/YPL RAOBS SHOWED INVRN
BASE JUST BLO H9 UNDER THIS SUBSIDENCE. THE LARGER SCALE SUBSIDENCE
HAS CAUSED SKIES TO TURN PCLDY OVER THE SCENTRAL. THERE IS ANOTHER
CLIPPER SHRTWV OVER THE DAKOTAS EMBEDDED IN THE NW FLOW ALF...BUT
THIS DISTURBANCE IS ON A TRACK THAT WL TAKE IT WELL TO THE SW OF UPR
MI.
MAIN FCST CONCERNS IN THE SHORT TERM INCLUDE LES POPS AND SN AMOUNTS
AS WELL AS WIND CHILLS AND GOING HEADLINES.
TNGT...UPR MI WL BE DOMINATED BY DEEP LYR QVECTOR DVGC UNDER
PERSISTENT NW FLOW ALF AND ON THE NRN FRINGES OF DAKOTA CLIPPER
SAILING SEWD TO THE S OF THE CWA. H85 TEMPS ARE FCST TO FALL TO AS
LO AS ABOUT -25C...SO LES WL CONTINUE IN THE FAVORED SN BELTS. BUT
AS THE SFC HI PRES OVER SCENTRAL CANADA SINKS TO SW MN BY 12Z TUE...
THE LLVL FLOW OVER UPR MI IS FCST TO BACK SLOWLY FM THE N TOWARD THE
NW WITH TIME...SO THE SN BANDS SHOULD SHIFT ACCORDINGLY. ALTHOUGH
THE LARGER SCALE H925-85 WL BE BACKING...A NUMBER OF THE HIER RES
MODELS STILL SHOW A NEAR SFC ENE LAND BREEZE FLOW OFF ONTARIO
ENHANCED BY NOCTURNAL COOLING IMPACTING THE ERN CWA AND SHARPENING
LLVL CNVGC IN ALGER/WRN LUCE/ NRN SCHOOLCRAFT COUNTIES. DESPITE THE
LARGER SCALE SUBSIDENCE... FCST SDNGS FOR THIS AREA SHOW INVRN BASES
UP NEAR 7K FT WITH LONGER FETCH OVER MORE OPEN ICE FREE WATER
ENHANCING MIXING. ALTHOUGH THE DGZ IS FCST TO LOWER TO WITHIN 1-2K
FT OF THE SFC...THESE CONDITIONS FAVOR GOING LES ADVY FOR THIS AREA.
SHIFTING WINDS/MORE ICE COVER OVER WRN LK SUP/LOWER INVRN BASE NEAR
3-4K FT/NEAR ABSENCE OF DGZ OVER THE W WITH COLDER...MORE UNMODIFIED
ARCTIC AIRMASS INDICATE NO MORE THAN A FEW INCHES WL FALL OVER THE
W. SINCE THE BACKING FLOW WL INTRODUCE MORE UNMODIFIED ARCTIC AIR
INTO THE W HALF OF UPR MI WITH MIN SFC TEMPS FALLING WELL BLO
ZERO...WL MAINTAIN GOING WIND CHILL ADVY EVEN THOUGH WINDS MAY NOT
MEET THE MINIMUM 10 MPH CRITERIA AT MANY LOCATIONS.
TUE...SFC ARCTIC HI PRES CENTER IS FCST TO DRIFT INTO FAR NW IL BY
00Z WED...RESULTING IN A SLOW BACKING/WEAKENING OF THE LLVL WINDS.
WITH PERSISTENT DEEP LYR QVECTOR DVGC AND MORE ACYC FLOW...THE LES
OVER THE W SHOULD DIMINISH AS THE BANDS SHIFT MAINLY INTO THE
KEWEENAW BY LATER IN THE DAY. AS THE WINDS DIMINISH...LLVL CNVGC
INTO THE ERN CWA IS ALSO FCST TO WEAKEN. IN CONCERT WITH TREND
TOWARD MORE DISORGANIZED BAND STRUCTURE WITH THE SHIFTING WINDS AND
A FCST LOWERING OF THE INVRN BASE UNDER THE SUSTAINED QVECTOR
DVGC... LES INTENSITY IN THE ADVY AREA OVER THE E SHOULD DIMINISH IN
THE AFTN. EXPECT MAX TEMPS TO STRUGGLE TO RISE MUCH ABV ZERO OVER
THE INTERIOR W...BUT DIMINISHING WIND WL MODERATE WIND CHILLS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 520 PM EST MON JAN 20 2014
NO BIG CHANGES IN THE OVERALL PATTERN THROUGH THE EXTENDED AS
RIDGING REMAINS IN PLACE OVER WESTERN NORTH AMERICA AND A BROAD
TROUGH ENVELOPS THE EASTERN TWO-THIRDS OF THE CONTINENT INCLUDING
THE GREAT LAKES REGION WHERE TEMPS WILL REMAIN BLO NORMAL THROUGH
MUCH OF THE PERIOD. THIS PATTERN WILL GENERALLY RESULT IN PERSISTENT
LIGHT TO MODERATE LAKE EFFECT SNOW FOR AREAS DOWNWIND OF LAKE
SUPERIOR WITH COLDER CONDITIONS AND LESSER CHCS FOR SNOW FOR
COUNTIES TO THE SOUTH.
TUESDAY NIGHT INTO WEDNESDAY NIGHT...MOST MODELS INDICATE LAND
BREEZES OFF ONTARIO AND UPPER MICHIGAN WILL PUSH MESOLOW AND ASSOC
LAKE EFFECT SNOW OFFSHORE OF ERN COUNTIES AND OUT OVER THE OPEN
WATERS OF ERN LAKE SUPERIOR. THIS OF COURSE WOULD RESULT IN A
TEMPORARY BREAK FROM LAKE EFFECT SNOW FOR ERN COUNTIES. AT SAME
TIME...MODELS ALSO SHOW A CLIPPER SYSTEM DESCENDING THROUGH
MANITOBA/ONTARIO TOWARD THE UPPER GREAT LAKES LATE TUE NIGHT INTO
WED WHICH IN TURN WILL ENHANCE MID-LAKE CONVERGNCE...LAKE-INDUCED
TROUGH AND ASSOC MESOLOW FEATURES ACROSS LAKE SUPERIOR. DEEP LAYER
MODERATE Q-VECT CONV AND MID-LVL MOISTENING AHEAD OF THE CLIPPER
SHOULD RESULT IN A WIDESPREAD DUSTING OF LIGHT SYSTEM SNOW LATE TUE
NIGHT INTO WED. LIGHT WINDS AND INCREASING CLOUDS AHEAD OF CLIPPER
SYSTEM SHOULD COMBINE TO KEEP WIND CHILLS GENERALLY GREATER THAN
-20F OR ABOVE ADVISORY CRITERIA TUE NIGHT.
WINDS VEERING NORTHERLY WED AFTERNOON/EVENING IN THE WAKE OF CLIPPER
SHORTWAVE WILL PUSH MESOLOWS AND MID-LAKE CONVERGENCE BANDS ONSHORE
INTO UPPER MI BRINGING THE THREAT OF MODERATE TO HEAVY SNOW FOR
COUNTIES ALONG LAKE SUPERIOR. WITH WIND SHIFT...EXPECT MODERATE LAKE
EFFECT SNOW TO MOVE OVER MAINLY OVER THE WRN COUNTIES ON WEDNESDAY
AND THEN MODERATE TO HEAVY SNOW TO MOVE INTO NCNTRL UPPER MI WED
AFTERNOON AND EVENING. DEEP LAYER Q-VECTOR CONVERGENCE AND LINGERING
DEEP MOISTURE SHOULD PROVIDE PLENTY OF ENHANCEMENT TO MESOLOWS AND
MID LAKE CONVERGENCE LES BANDS RESIDING OVER LAKE SUPERIOR ON
WEDNESDAY. NAM AND LOCAL WRF-ARW ALSO SHOW STRONG PRES RISES IN THE
WAKE OF THE CLIPPER SHORTWAVE AND ASSOC SFC TROUGH/SECONDARY COLD
FRONTAL PASSAGE. FCST SNDGS ALSO INDICATE CONVECTIVE BOUNDARY LAYER
WINDS 35-40 KTS WHICH WILL CONTRIBUTE TO CONSIDERABLE BLOWING AND
DRIFTING OF LAKE EFFECT SNOW AND OCCASIONAL WHITEOUT CONDITIONS. LOW
LEVEL CONVERGENCE AND MODEL QPF FIELDS SUGGEST HEAVIEST BANDS WILL
FOCUS INTO MQT COUNTY WED AFTERNOON INTO WED EVENING. GIVEN
FAVORABLE CONDITIONS FCST FOR HEAVY LES AND BLOWING SNOW POTENTIAL
DECIDED TO ISSUE A LAKE EFFECT SNOW WATCH FOR MQT COUNTY WED
AFTERNOON INTO WED NIGHT. FOR NOW ONLY INCLUDED MQT COUNTY IN
WATCH...BUT WOULD NOT BE SURPRISED IF HEADLINES WILL ALSO BE NEEDED
FOR BARAGA AND WRN ALGER COUNTIES FOR PERIODS OF MODERATE TO
OCCASIONALLY HEAVY LES DURING THIS TIME FRAME.
AS WINDS BACK NW WITH APPROACH OF SFC RDG FM THE NORTHERN
PLAINS...LINGERING LIGHT TO MODERATE LES BANDS WILL SHIFT EAST
ACROSS THE ERN HALF OF THE CWA LATE WED NIGHT INTO THU.
OTHER THAN SOME LINGERING LIGHT LES EARLY EVENING ALONG THE FAR ERN
SHORELINE...WINDS BACKING WSW SHOULD PUSH ANY REMAINING LES OUT OVER
ERN LAKE SUPERIOR BRINGING A VERY BRIEF BREAK FROM SNOW THU EVENING
BEFORE YET ANOTHER WEAKER CLIPPER SYSTEM BRINGS IN A CHC FOR MORE
WIDESPREAD LIGHT SNOW LATE THU NIGHT INTO FRI. BOTH THE ECMWF AND
GFS SHOW ANOTHER CLIPPER SHORTWAVE MOVING LATE FRI/FRI EVENING WITH
INCREASED MOISTENING...DEEP LAYER Q-VECT CONV ALONG WITH CONVERGENT
W-WNW FLOW FRI AFTERNOON INTO FRI EVENING TO BRING AN INCREASED
POTENTIAL FOR MODERATE LES INTO THE NW CWA. WITH BLYR WINDS FCST
OVER 30 KTS ACROSS KEWEENAW AND LK SUPERIOR...THERE WILL LIKELY BE
SIGNIFICANT BLSN/DRSN AND POOR VSBY AS WELL.
MOST MODELS SHOW POLAR VORTEX DESCENDING NEAR TIP OF JAMES BAY THIS
WEEKEND. AT THIS TIME IT APPEARS THAT HEART OF COLDEST AIR (8H TEMPS
-35F OR LOWER) WILL STAY NE OF THE UPPER GREAT LAKES BUT SHORTWAVE
LOBES ROTATING AROUND THIS FEATURE COULD BRING WAVE OF 8H TEMPS OF
-28 TO -30F ACROSS THE CWA LATE SUNDAY INTO EARLY MONDAY. EXPECT
HIGHS AROUND 10F TO LOWER TEENS ON SATURDAY WILL DROP BACK INTO
SINGLE DIGITS ON SUNDAY AND PERHAPS MAY STRUGGLE TO REACH ABV ZERO
AT SOME WRN INTERIOR LOCATIONS ON MONDAY. WILL MAINTAIN HIGHER CHC
TO LIKELY POPS FOR MAINLY LIGHT NW FLOW LES SATURDAY INTO MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1222 PM EST MON JAN 20 2014
A COLD N WIND SLOWLY BACKING NW WL BRING LK EFFECT -SHSN TO UPR MI
THIS FCST PERIOD. HOWEVER...A FEED OF LLVL DRY AIR AND LO INVRN BASE
ASSOCIATED WITH ARCTIC HI PRES OVER SCNTRL CANADA WL TEND TO LIMIT
THE INTENSITY OF THE SHSN. ALTHOUGH CONDITIONS MAY VARY SGNFTLY AS
IS OFTEN THE CASE DURING LK EFFECT SN EVENTS...EXPECT MVFR
CONDITIONS TO PREDOMINATE. IWD WL SEE IFR CONDITIONS IN THE SHORT
TERM WITH FVRBL NNE FLOW DOWN THE LENGTH OF WRN LK SUP. THE BEST CHC
FOR VFR WX WL BE AT SAW WITH A MORE DOWNSLOPE NW WIND AND AT IWD ON
TUE MRNG ONCE THE FLOW BACKS SUFFICIENTLY TO FLOW OFF ICE BUILDUP AT
THE SW END OF LK SUP.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 PM EST MON JAN 20 2014
WITH NNW WINDS UP TO 20-30 KTS ADVECTING ARCTIC AIR INTO THE UPPER
GREAT LAKES...EXPECT HEAVY FREEZING SPRAY TO CONTINUE INTO TUE FOR
PORTIONS OF THE E HALF OF LAKE SUPERIOR. BUT DIMINISHING WINDS ON
TUE WILL CAUSE THIS HEAVY FREEZING SPRAY TO GRADUALLY DIMINISH. NEXT
GALE EVENTS ALONG WITH HEAVY FREEZING SPRAY LOOK TO BE ACROSS
CENTRAL AND EASTERN LAKE SUPERIOR LATE WEDNESDAY INTO WEDNESDAY NIGHT
AND ANOTHER EVENT FOR THURSDAY NIGHT ACROSS THE SAME AREA. ANOTHER
GALE IS POSSIBLE FOR EASTERN LAKE SUPERIOR LATE FRI NIGHT INTO
SATURDAY ALONG WITH MORE HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO 11 AM EST
/10 AM CST/ TUESDAY FOR MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST TUESDAY FOR MIZ006-007-
085.
LAKE EFFECT SNOW WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
MORNING FOR MIZ005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR LSZ251-
267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR LSZ249-
250-266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST TUESDAY FOR LSZ244-
245-248-264-265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
139 PM CST MON JAN 20 2014
.SYNOPSIS...
ISSUED AT 344 AM CST MON JAN 20 2014
BROAD WEST NORTHWEST FLOW AT H5 WAS PRESENT ACROSS THE
CONUS TONIGHT WITH A CLOSED LOW NOTED OVER SRN PORTIONS OF HUDSON
BAY WITH RIDGING EXTENDING UP THE WEST COAST INTO THE YUKON. A
DECENT SHORTWAVE WAS NOTED OVER NRN SASKATCHEWAN WITH 50 TO 80 METER
HT FALLS NOTED OVER MT...THE DAKOTAS AND MN. AT THE SURFACE...AN
ARCTIC COLD FRONT EXTENDED FROM SRN SASKATCHEWAN...INTO FAR
NORTHEASTERN SD AND CENTRAL MINNESOTA. TEMPERATURES BEHIND THIS
FRONT WERE IN THE SINGLE DIGITS OVER NERN ND AND FAR NRN MN...WHILE
SOUTH OF THE FRONT...TEMPERATURES WERE IN THE 30S ACROSS MOST OF
SOUTH DAKOTA...WESTERN ND AND NEBRASKA. SOME 20S WERE NOTED OVER THE
NEBRASKA SANDHILLS AND PLATTE RIVER VALLEY WHERE WINDS WERE LIGHT
FROM THE WEST AND NORTHWEST.
&&
.UPDATE...
ISSUED AT 139 PM CST MON JAN 20 2014
UPDATED THE FORECAST TO ADD PATCHY BLOWING SNOW AND PATCHY BLOWING
DUST FOR PORTIONS OF THE FORECAST ARE THIS AFTERNOON. RADAR WAS
PICKING UP A VERY WEAK BAND OF PRECIPITATION ACROSS NORTH CENTRAL
NEBRASKA ALONG THE FRONT EDGE OF THE ARCTIC AIR WHICH WAS ROUGHLY
FROM MERRIMAN TO BREWSTER TO BARTLETT. OBSERVATIONS HAVE SHOWN
REDUCED VISIBILITIES IN SNOW AS THIS BAND HAS MOVED THROUGH. THE
REFLECTIVITIES ARE VERY LIGHT...AND WINDS ARE GUSTING TO 50 MPH
ACROSS THOSE LOCATIONS...BELIEVE THE SNOW IS NOT ACTUALLY
MEASURABLE AND VISIBILITY REDUCTIONS ARE DUE TO BLOWING SNOW. SO
ADDED PATCHY BLOWING SNOW TO THOSE AREAS THROUGH THE AFTERNOON AS
SUBSEQUENT AREAS OF LIGHT SNOW WILL MOVE INTO THE AREA IN THE COLD
AIR THROUGH THE AFTERNOON. ALSO...REPORTS OF SOME PATCHY BLOWING
DUST HAVE BEEN RECEIVED WHERE SOME OF THE HIGHER WINDS HAVE BEEN
OBSERVED ACROSS SOUTHWEST NEBRASKA...SO ADDED THAT INTO THE
FORECAST FOR THE AFTERNOON IN THOSE LOCATIONS AS WELL.
OTHERWISE FORECAST REMAINS ON TRACK. TEMPERATURES HAVE BEGUN TO
FALL OVER THE NORTHERN COUNTIES...WHILE LAPS SOUNDINGS SHOW THE
REMAINDER OF THE AREA HAS REACHED MAXIMUM MIXING HEIGHT AND WITH
COLD AIR ADVECTION ALOFT DON/T BELIEVE THERE WILL BE MUCH FURTHER
WARMING THROUGH THE AFTERNOON.
IN TERMS OF WINDS...HAVE RECEIVED A FEW ISOLATED REPORTS OF GUSTS
TO 58 MPH OVER EXTREME NORTH CENTRAL NEBRASKA. BOTH THE RAP AND
NAM MODELS WERE A BIT STRONG WITH PRESSURE RISES OVER SOUTH DAKOTA
WHEN COMPARED TO MSAS DATA. THESE EXTREME PRESSURE RISES WILL
MOVE FROM CENTRAL SOUTH DAKOTA INTO EASTERN NEBRASKA THROUGH THIS
EVENING...BUT THE MODELS ARE INDICATING THE RISES WILL WEAKEN AS
IT MOVES SOUTHEAST THROUGH THE AFTERNOON. THINK IF ANY FURTHER
GUSTS TO 58 MPH OCCUR IT WILL BE VERY ISOLATED AND MOST PLACES
WILL BE AT HIGH END ADVISORY THROUGH THE DAY SO WILL FORE-GO
UPGRADING TO HIGH WIND WARNING THIS AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CST MON JAN 20 2014
FOR TODAY...THE ARCTIC COLD FRONT WILL PUSH INTO NRN NEBRASKA
AROUND 15Z...CLEARING THE FORECAST AREA BY MID AFTERNOON.
TEMPERATURES WILL BE KIND OF TRICKY TODAY GIVEN THE ARCTIC FROPA.
BASED ON CURRENT FORECAST TRENDS...HIGHS WILL BE FAIRLY EARLY IN
THE NORTH AROUND NOONTIME WITH FALLING AFTERNOON TEMPS...WHILE
FURTHER SOUTH...HIGHS WILL FOLLOW A TYPICAL DIURNAL CURVE AND
OCCUR IN THE MID AFTERNOON. GUIDANCE TODAY CONTINUES TO RUN TOO
COOL...IN PARTICULAR THE LATEST MET GUIDANCE...WHICH HAS A HIGH OF
37 FOR NORTH PLATTE. EVEN THE WARMER MAV GUIDANCE OF 44 FALLS
SHORT GIVEN THE FCST H85 TEMPS OF 1 TO 2C TDY AND DECENT MIXING
POTENTIAL VIA INCREASING NRLY WINDS LATER THIS MORNING. FOR
VALENTINE...GUIDANCE TEMPS ARE RIGHT AROUND THE FREEZING
MARK...WHICH IS COOLER THAN THE CURRENT TEMP OF 33. BEFORE THE
LEADING EDGE OF THE ARCTIC AIR ARRIVES BY LATE MORNING...WE SHOULD
BE ABLE TO REACH THE MIDDLE 30S ALONG THE SD/NEBR BORDER. LATER
THIS MORNING...AS THE CORE OF THE ARCTIC AIR PUSHES INTO THE NERN
FORECAST AREA...THERE WILL BE A SMALL THREAT FOR LIGHT SNOW
SHOWERS OR FLURRIES. TIME SECTIONS ACROSS THE FAR NERN
CWA...INDICATE A SHALLOW MOIST LAYER FROM H85-H70 ROUGHLY ACROSS
HOLT AND BOYD COUNTIES...WHICH IS COLOCATED WITH SOME WEAK LIFT IN
THE DENDRITIC LAYER. THIS LIFT IS VERY SHORT LIVED AND IS CENTERED
AROUND 21Z THIS AFTERNOON. DECIDED LEAVE IN A MENTION OF ISOLATED
SNOW SHOWERS ACROSS THE FAR NERN FORECAST AREA...BUFFERED BY A
BAND OF FLURRIES FROM NORTH OF AINSWORTH TO SOUTH OF EWING. THE
FINAL FORECAST CHALLENGE WITH BE THE WIND THREAT TODAY AND INTO
THE EVENING. THE COMBINATION OF STRONG COLD AIR ADVECTION BEHIND
THE FRONT...STRONG PRESSURE RISES AND A NICE MID LEVEL PV MAX WILL
PRODUCE VERY WINDY CONDITIONS LATER THIS MORNING INTO THE EARLY
EVENING HOURS. H85 WINDS WILL PUSH 40 TO 50 KTS BY MID MORNING IN
THE EAST...THEN INTO THE AFTERNOON HOURS IN THE WEST. TYPICALLY IN
THIS SETUP...WIND ADVISORY CRITERIA WINDS END QUICKLY TOWARD
SUNDOWN...HOWEVER...STRONG COLD AIR ADVECTION WILL CONTINUE IN THE
EAST THROUGH MID EVENING. WITH THIS IN MIND...FEEL INCLINED TO
EXTEND THE WIND ADVISORY THROUGH 3Z ROUGHLY EAST OF A VALENTINE TO
ARNOLD LINE. ARCTIC HIGH PRESSURE WILL PUSH INTO NERN NEBRASKA
TOWARD 12Z TUESDAY...WITH COLD AIR ADVECTION ENDING BY LATE
EVENING. OVERNIGHT LOWS WILL BE COLD TONIGHT...RANGING FROM AROUND
ZERO IN THE NORTH CENTRAL AND NORTHEAST...TO AROUND 10 ABOVE IN
THE SOUTHWEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 344 AM CST MON JAN 20 2014
UPPER LEVEL PATTERN REMAINS UNCHANGED THROUGH THE PERIOD...WITH A
LARGE UPPER LEVEL LOW TO REMAIN ANCHORED ACROSS SOUTHEAST CANADA.
THIS IS THE CENTER OF A LARGE UPPER LEVEL TROUGH OF LOW PRESSURE
WHICH WILL REMAIN ACROSS THE EAST COAST REGION. MEANWHILE A LARGE
UPPER LEVEL RIDGE WILL CONTINUE ACROSS THE WEST COAST STATES. OUR
AREA WILL REMAIN IN BETWEEN THESE TWO FEATURES...WITH BROAD
NORTHWEST FLOW ALOFT.
A COUPLE OF SHORTWAVES ALOFT AND THEIR ASSOCIATED COLD FRONTS WILL
BE EMBEDDED WITHIN THE FLOW...WITH A STRONG ARCTIC COLD FRONT SET TO
ARRIVE WEDNESDAY. PRIOR TO THE COLD FRONT ARRIVAL...A WESTERLY
CHINOOK WIND WILL BRING A VERY MILD DAY TO THE AREA TUESDAY...WITH
LOCATIONS WEST OF HWY 83 SEEING HIGHS OF 50 DEGREES OR BETTER.
AS MENTIONED...A STRONG ARCTIC COLD FRONT ARRIVES LATER
WEDNESDAY...WITH FALLING AFTERNOON TEMPERATURES AND GUSTY NORTH
WINDS. MODELS AGREE THAT A STRONG ARCTIC HIGH PRESSURE CENTER NEAR
1050 MB WILL BE CENTERED ACROSS EASTERN NEBRASKA AT 18Z THURSDAY.
WILL SHAVE A FEW MORE DEGREES OFF HIGHS THURSDAY...AS THE AIRMASS
ASSOCIATED WITH THIS HIGH IS QUITE COLD.
CONDITIONS RAPIDLY IMPROVE FRIDAY INTO THE WEEKEND...AS WARMING
WESTERLY DOWNSLOPE CHINOOK WINDS DEVELOP ONCE AGAIN. BY SATURDAY
HIGH TEMPERATURES ARE FORECASTED TO BE BACK INTO THE 50S ACROSS
WESTERN NEB. SUNDAY WILL BE A BIT COOLER...AS A WEAK COLD FRONT
SLIDES SOUTH INTO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1203 PM CST MON JAN 20 2014
WINDS ARE THE PRIMARY ISSUE FOR AVIATION CONCERNS THROUGH THE NEXT
24 HOURS. STRONG NORTHWEST WINDS WILL CONTINUE ACROSS ALL OF
NEBRASKA THIS AFTERNOON...THEN WILL TAPER OFF THIS EVENING. TOP
WINDS WILL OCCUR BETWEEN 18Z AND 22Z...THEN AFTER 22Z SHOULD START
TO DECREASE. STRONGER WINDS WILL CONTINUE EAST OF A KVTN TO KLBF
LINE INTO THE EVENING HOURS. OVERNIGHT...HIGH PRESSURE WILL DRIFT
SOUTH ALONG THE MISSOURI RIVER VALLEY WITH WINDS DROPPING OFF AND
SWITCHING TO THE SOUTH. BY LATE MORNING TUESDAY...MOST AREAS
SHOULD SEE WINDS BEGINNING TO INCREASE FROM THE SOUTH SOUTHWEST. A
BAND OF MVFR CLOUDS SHOULD MOVE SOUTH OUT OF NORTHEAST
WYOMING/WESTERN SOUTH DAKOTA THIS EVENING...GENERALLY HITTING
AREAS ALONG A LINE FROM KVTN TO KODX. BY 12Z TUESDAY ONLY CLOUDS
ABOVE 8K FEET ARE EXPECTED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR NEZ004-
022>024-035-036-056>059-069>071-094.
WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ005>010-025>029-
037-038.
&&
$$
UPDATE...BROOKS
SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...TAYLOR
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1140 AM CST MON JAN 20 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 411 AM CST MON JAN 20 2014
ON THE MAP EARLY THIS MORNING...AS WELL AS EVIDENT ON THE OVERNIGHT
SATELLITE IMAGERY...IS BACKDOOR ARCTIC BOUNDARY EXTENDING FROM WEAK
LOW PRESSURE IN CENTRAL NORTH DAKOTA TO CENTRAL MINNESOTA. ELONGATED
UPPER WAVE WITH ONE CENTER IN NORTHERN WISCONSIN...A SECOND IN NORTH
DAKOTA...AND MOST IMPORTANTLY A THIRD IN SOUTHERN SASKATCHEWAN.
EXTREMELY COMPLEX FORECAST IN THE SHORT TERM DEALING WITH CHANGES IN
TEMPERATURE...POP DISTRIBUTION...AND WIND ASSOCIATED WITH THE
BOUNDARY PASSAGE. TIMING OF BOUNDARY HAS COME INTO A CLEARER FOCUS
ON 00Z/06Z SOLUTION SETS...BACKING TO HURON/SIOUX FALLS/SPENCER LINE
BEHIND WEAK SURFACE WAVE MOVING INTO CENTRAL IOWA BY 18Z...THEN
CONTINUING A QUICKENING PACE SOUTHWARD THROUGH THE REST OF THE
AFTERNOON. LOCATION IS IMPORTANT AS MOST OF THE PRECIPITATION WILL
BE POST FRONTAL...AND TO CONSIDER LOCATIONS WITH GREATER POTENTIAL
TO WARM AHEAD OF THE BOUNDARY.
WIND IS THE FIRST FEATURE OF THE SYSTEM TODAY. WILL BE FAIRLY WELL
MIXED ALONG AND AHEAD OF THE BOUNDARY...AND WILL SEE 925 HPA WINDS
INCREASE TO 30 TO 40 KNOTS DURING THE LATER MORNING AS SYSTEM
APPROACHES. LOOKS LIKE CLASSIC MISSOURI VALLEY TRACK TO STRONGEST
OFF SURFACE WIND CORE FROM 925 TO 850 HPA. WILL ALSO BE WATCHING
MASSIVE PRESSURE RISES OF 8-12 HPA/3H ASSOCIATED WITH THE FINAL WAVE
WHICH TIMES OUT TO DIG ACROSS THE AREA EARLY TO MID AFTERNOON. THIS
COULD PROVIDE A STRONG PULSE TO WINDS WHICH WILL WORK THROUGH THE
AREA. HAVE ISSUED A WIND ADVISORY FOR AREAS WEST OF THE JAMES
RIVER...THEN INTO THE LOWER MISSOURI VALLEY FROM LATE MORNING
THROUGH THE AFTERNOON. MAY END UP HAVING TO ADD COUPLE MORE TIERS
OF COUNTIES EASTWARD INTO THE WIND ADVISORY IF TRENDS IN 06Z NAM
WIND/PRESSURE TENDENCY CONTINUE TO BECOME EVIDENT. NO REASON TO
DOUBT WITH 9-10 HPA/3H RISES ON CURRENT ANALYSIS.
HAVE MAINTAINED THE HIGH POPS IN THE FORECAST ADVERTISED OVER THE
PAST COUPLE OF DAYS...BUT DID SLOW UP THE ONSET SOME EARLY THIS
MORNING. SOUNDINGS INDICATE THAT WILL GET A STRONG COOLING AND
SATURATION IN THE DENDRITIC ZONE. LIFT PROVIDED PRIMARILY WITH THE
ADVANCE OF THE COLD AIR...A SHALLOW FORCING. COULD BE A LITTLE
BROADENING OF THE PRECIP AREA THIS AFTERNOON AS THE DEEPER MOISTURE
AND UPPER LEVEL FORCING INCREASES WITH PASSAGE OF THIRD UPPER WAVE
ENERGY...BUT FOR THE MOST PART THE FLAVOR OF THE SNOW DISTRIBUTION
IS TIED TO THE 925-850 HPA FRONTOGENESIS. WILL LIKELY END UP WITH A
BAND OF A INCH OR A LITTLE MORE FROM PARTS OF EAST CENTRAL SD INTO
NW IA...TAPERING TO LESS THAN A HALF INCH WEST OF THE JAMES RIVER.
AT THIS TIME...NOT EXPECTING SIGNIFICANT PROBLEMS WITH BLOWING SNOW
AS STRONGEST WINDS WILL LIKELY OCCUR IN AREAS THAT HAVE MELTED TO
SNOW FREE PRIOR TO SNOWFALL TODAY...AND GREATER AMOUNTS WILL OCCUR
WITH SOMEWHAT WEAKER WINDS.
CURRENTLY...TEMPERATURES FOR THE MOST PART HAVE BEEN RUNNING WARMER
THAN GUIDANCE WITH A PERSISTENT MODEST WEST NORTHWEST WIND AHEAD OF
THE ADVANCING BOUNDARY ALONG WITH HIGH CLOUDS. WILL HAVE THESE
CLOUDS THIN SOMEWHAT LATE IN CURRENT NIGHT...AND IF WINDS DROP A BIT
WILL KNOCK TEMPS DOWN. HIGHS UP NORTH ARE CERTAINLY GOING TO BE
EARLY IN THE DAY AND THEN SEE A DRASTIC PLUNGE BEHIND THE BACKDOOR
BOUNDARY. COMPLEX FORECAST AS THERE IS SOME QUESTION AS TO HOW WARM
IT MAY GET AHEAD OF THE BACKDOOR PUSH THROUGH THE MISSOURI VALLEY
TODAY...WITH WARMEST SOLUTION IN RAP SUGGESTING SOME LOWER TO MID
40S ARE AN EASY REACH. MADE SOME DRASTIC CHANGES TO THE TEMP
FORECAST FOR TODAY...WARMING UP SOME LOCATIONS 7-10 DEGREES FROM
EARLIER FORECAST...AND EVEN UP A HALF DOZEN IN THE NORTH IN PLACES
WITH HOPES THAT DO NOT GET TOO MUCH OF A LATE NIGHT DIP.
FINALLY...WIND CHILLS WILL PLUMMET TO 20 BELOW TO 30 BELOW ZERO
TONIGHT FROM JUST WEST OF THE INTERSTATE 29 CORRIDOR IN SD TO JUST
EAST OF IT AROUND KSUX. WHILE REALIZE THAT NORTHERN AREAS WILL KICK
INTO CRITERIA A BIT SOONER AND SOUTHERN LOCATIONS LATER...BUT
STARTED ALL LOCATIONS UP AT THE SAME TIME FOR SIMPLICITY. DID
THROUGH DROP OFF THE WESTERN HALF LATE AT NIGHT GIVEN THE SPRAWLING
SURFACE RIDGE AND LIKELIHOOD OF LIGHT WINDS...COMPARED TO LOCATIONS
FURTHER EAST IN SW MN AND NW IA. EVEN WITHOUT WINDS...WILL SEE SOME
LOWS WELL INTO THE TEENS BELOW ZERO...BUT ALSO SHOULD START TO GET
SOME MODIFICATION TO READINGS LATER IN THE WEST WITH WEAK SOUTHERLY
FLOW AND THICKER HIGH CLOUDS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 411 AM CST MON JAN 20 2014
A VERY COLD START TO THE MORNING ON TUESDAY AS COLD HIGH PRESSURE
GRADUALLY DRIFTS EASTWARD. SOME WARMING WILL TRY TO DEVELOP BUT WILL
LIKELY BE LIMITED TO AREAS ALONG AND WEST OF THE JAMES RIVER VALLEY
AS THE STUBBORN COLD HIGH PRESSURE WILL LIMIT THE PUSH OF WARMER
AIR. HIGHS WILL LIKELY VARY FROM ABOUT THE MID 30S NEAR GREGORY SD
TO NEAR 10 ABOVE IN SOUTHWEST MINNESOTA.
AS LOW PRESSURE ALOFT DROPS INTO THE NORTHERN GREAT LAKES TUESDAY
NIGHT INTO WEDNESDAY WINDS WILL TURN FROM THE SOUTHWEST TO THE WEST
AND NORTHWEST OVERNIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING
TOO FAR OVERNIGHT BUT WILL ALSO LIMIT THE RISE ON WEDNESDAY AS THE
COLDER AIR SURGES SOUTH...ESPECIALLY IN THE AFTERNOON. THERE WILL BE
A SMALL THREAT FOR LIGHT SNOW AS WARM ADVECTION DEVELOPS TUESDAY
NIGHT BUT DRY AIR SHOULD LIMIT THOSE CHANCES TO MAINLY SOUTHWEST
MINNESOTA. LOWS ON TUESDAY NIGHT NEAR ZERO IN SOUTHWEST MINNESOTA TO
NEAR 20 IN SOUTH CENTRAL SD. TEMPERATURES ON WEDNESDAY SHOULD CLIMB
INTO THE MID TO UPPER 20S ON WEDNESDAY DOWN THE MISSOURI RIVER
CORRIDOR BUT ONLY IN TO THE SINGLE DIGITS IN THE NORTHERN CWA AS THE
COLDER AIR WORKS SOUTH. IN FACT...MOST LOCATIONS SHOULD SEE FALLING
TEMPERATURES IN THE AFTERNOON.
WEDNESDAY NIGHT INTO THURSDAY LOOKS PRETTY DARN COLD AS A 1050 MB
HIGH PRESSURE BUILDS INTO THE AREA. THIS SHOULD ALLOW TEMPERATURES
TO FALL WELL INTO THE MID TEENS BELOW ZERO. AND WITH WEAK MIXING ON
THURSDAY HIGHS WILL ONLY REACH THE SINGLE DIGITS IN MOST SPOTS WITH
15 TO 20 WEST OF THE JAMES RIVER VALLEY.
IN THE OUTER PERIODS...FRI/SUN...A FAIRLY STRONG NORTH TO NORTHWEST
FLOW ALOFT REESTABLISHES WHICH KEEPS THE AREA WITHIN A VARIABLE
THERMAL REGIME. WILL NOT LEAN HARD IN ANY ONE DIRECTION DURING THIS
TIME AS THE THERMAL GRADIENT IS LARGE ENOUGH ACROSS THE AREA THAT
THE TIMING AND LOCATION OF ANY WAVE WILL MAKE POTENTIALLY VERY LARGE
DIFFERENCES. OVERALL WILL LEAN TOWARDS SLIGHTLY ABOVE NORMAL
TEMPERATURES ON FRIDAY AND SATURDAY AND BELOW NORMAL TEMPERATURES BY
SUNDAY. A SMALL CHANCE FOR LIGHT SNOW SATURDAY BUT THIS LIKE THE
TEMPERATURES IS A BIT VARIABLE SO NO BIG CHANCES NOR ANY THREAT FOR
ANY MAJOR SYSTEMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1137 AM CST MON JAN 20 2014
ARCTIC BOUNDARY SURGING SOUTH WITH SNOWFALL TEMPERARILY REDUCING
VISILITY BEHIND THE FRONT FOR A FEW HOURS. CEILINGS WILL ALSO
TUMBLE INTO THE MVFR IF NOT BRIEFLY THE IFR CATEGORY...BEFORE
IMPROVING AGAIN THIS EVENING. STRONG NORTHWEST WINDS WILL ALSO
DECREASE THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 5 PM CST THIS AFTERNOON FOR SDZ050-052-053-
057>060-063>065-068>071.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR SDZ039-040-055-056-062-067.
MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR MNZ071-097-098.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR MNZ072-080-081-089-090.
IA...WIND ADVISORY UNTIL 5 PM CST THIS AFTERNOON FOR IAZ020-031.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST TUESDAY
FOR IAZ001-012.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST TUESDAY
FOR IAZ002-003-013-014-021-022-032.
NE...WIND ADVISORY UNTIL 5 PM CST THIS AFTERNOON FOR NEZ013-014.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
343 PM CST MON JAN 20 2014
.TONIGHT - CONFIDENCE...MEDIUM
THREE MAIN ISSUES TO ZERO IN ON. FIRST IS THE ENDING OF THE SYNOPTIC
SNOWS. LATEST HRRR DOES NOT ACCOUNT FOR THE NE EXTENT OF SNOW SWATH.
WILL BASE FORECAST ON RADAR ANIMATION BRINGING A STEADIER SNOW BAND
ACROSS SW 1/2 OF CWA. SHORTWAVE AND LOW LEVEL FRONTOGENETICAL FORCING
EXPECTED TO LOSE INFLUENCE BEYOND MID EVENING OR SO. UPSTREAM VSBYS
IN THE MAIN BAND 1-2SM SO EXPECT SOME LIGHT ACCUMULATION. NEXT FOCUS
IS ON LAKE EFFECT POTENTIAL. BUFKIT SOUNDINGS DO SUGGEST A WINDOW OF
BORDERLINE ONSHORE FLOW EVOLVING VCNTY MID LAKE EAST OF KMTW. DELTA T
RISES AS HIGH AS 20-22 WITH THE ARCTIC INVASION WITH EQUILIBRIUM LEVELS
RISING TO NEAR 7K FEET. HOWEVER FAIRLY STRONG SUBSIDENCE ALSO NOTED
IN THE WAKE OF THE SHORTWAVE AND INCREASING COLD AIR ADVECTION. 4KM
WRF SHOWS THE BAND STAYING JUST EAST OF THE SHORE WITH THE THE OTHER
MODELS SHOWING AT LEAST SOME LIGHT QPF BRUSHING THE FAR SE CORNER.
WILL KEEP SOME POPS GOING IN THE FAR SE LATER IN THE NIGHT TO
ACCOUNT FOR THE POTENTIAL. LAST CONCERN BUT CERTAINLY NOT LEAST IS
THE BITTER COLD WIND CHILLS. 925 TEMPS PROGGD TO DROP AS LOW AS -19
TO -21C WITH 25 KNOTS. WITH WIND CHILLS PROGGD TO REACH -20 IN AT
LEAST THE WESTERN PORTIONS OF LAKE COUNTIES...WILL EXPAND WIND CHILL
ADVISORY FOR THE REST OF THE AREA. COORD WITH KLOT ON THIS.
.TUESDAY - CONFIDENCE...MEDIUM
BITTERLY COLD WIND CHILLS AT THE OUTSET. PRESSURE GRADIENT PROGGD TO
STILL BE FAIRLY TIGHT THOUGH GRADUALLY EASES DURING THE AFTERNOON AS
HIGH PRESSURE RIDGES INTO WRN WI. TEMPS WILL STRUGGLE INTO THE SINGLE
DIGITS. COLD THERMAL TROUGH IN PLACE WITH 925 TEMPS -17 TO -19C.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
.TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
MODELS REMAIN IN FAIRLY GOOD AGREEMENT WITH A LEAD SHORT WAVE TROUGH
MOVING THROUGH THE REGION WEDNESDAY MORNING FOLLOWED BY...AND BEING
ABSORBED BY...A STRONGER WAVE WEDNESDAY AFTERNOON. HAVE KEPT TUESDAY
EVENING DRY THEN BRING CHANCE/LIKELY POPS INTO ALL BUT THE FAR EAST
BETWEEN 06Z AND 12Z WITH MAINLY ISENTROPIC FORCING AHEAD OF LEAD
WAVE...AND WENT WITH CONSENSUS BLEND FOR WEDNESDAY AS MAIN SHORT
WAVE PASSES THROUGH. MOST OF THE SNOW LOOKS TO FALL IN THE MORNING
WEDNESDAY AS ALL MODELS BUT THE NAM CURRENTLY LIMITING SNOW AFTER
18Z TO THE LAKESHORE COUNTIES....WHICH IS WHY THE CONSENSUS BLEND
SHOWS NO BETTER THAN HIGH CHANCE POPS FOR THE 12 HOUR PERIOD...SO
RAISED POPS TO LIKELY FOR THE MORNING AND DROP THEM TO SLIGHTS IN
THE WEST FOR THE AFTERNOON.
LOOKING FOR LOWS AROUND 12 MIDNIGHT TUESDAY NIGHT WITH NORTHERN TIP
OF SURFACE RIDGE AXIS OVER AREA...THEN TEMPS STEADY OR SLOWLY RISE
WITH INCREASING CLOUDS. APPARENT TEMPERATURES APPROACH WIND CHILL
CRITERIA AROUND 06Z THEN RISE WITH THE TEMPS. HIGHS IN THE TEENS
AROUND/SHORTLY AFTER NOON THEN FALLING TEMPS AS SURFACE TROUGH/COLD
FRONT MOVE THROUGH THE FORECAST AREA BY 00Z THURSDAY.
.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE HIGH.
ARCTIC AIR STREAMS BACK IN ON BRISK NORTHWEST WINDS AS BROAD HIGH
SETTLES SOUTH FROM THE NORTHERN TO CENTRAL PLAINS DURING THE DAY.
925 MB TEMPS FALL TO AROUND -20C BY 12Z THURSDAY WITH LOWS DROPPING
BELOW ZERO EXCEPT NEAR THE LAKESHORE...AND CLOSE TO 10 BELOW IN THE
FAR WEST. EXPECT TO REACH WIND CHILL ADVISORY CRITERIA EVERYWHERE
BUT THE FAR EAST AFTER MIDNIGHT. COULD SEE SOME PATCHY BLOWING SNOW
AND DRIFTING SNOW WITH THE STIFF WINDS THURSDAY MORNING. HIGHS ONLY
REACH THE SINGLE DIGITS ABOVE THURSDAY.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE
MEDIUM.
ACTIVE PATTERN BRINGS ANOTHER CLOSED 500 MB LOW DOWN TOWARD JAMES BAY
FRIDAY WITH DEVELOPING WESTERLY FLOW BEGINNING TO MODIFY 925MB-850
MB TEMPS AFTER MIDNIGHT THURSDAY....THOUGH BELOW ZERO LOWS AND WEST
WINDS BRING ANOTHER CHANCE FOR WIND CHILL HEADLINES THURSDAY NIGHT.
NON-DIURNAL TRENDS TO TEMPS FRIDAY/FRIDAY NIGHT AHEAD OF TROUGH
DROPPING INTO WESTERN GREAT LAKES...WITH 24 HOUR HIGHS REACHED LATE
IN THE DAY/EARLY EVENING FRIDAY...AND BEFORE SUNRISE SATURDAY.
CHANCE OF SNOW AS COLD FRONT DROPS THROUGH SATURDAY...WITH WELL
BELOW NORMAL TEMPERATURES FOR THE REST OF THE WEEKEND INTO NEXT
MONDAY.
&&
.AVIATION/00Z TAFS...ARCTIC FRONT WILL CONTINUE TO SLIDE TO OUR
SOUTH INTO THIS EVENING. LIGHT SNOW ASSOCIATED WITH SHORTWAVE
ACTIVITY WITHIN THE BROADLY CYCLONIC FLOW AND LOWER LEVEL
FRONTOGENETICAL FORCING WILL KEEP THE LIGHT SNOW GOING INTO THIS
EVENING. LOW LEVEL ONSHORE FLOW DEVELOPS FOR A TIME TONIGHT. WILL BE
WATCHING FOR ANY LAKE EFFECT BAND BRUSHING AREAS FROM KMKE
SOUTHWARD. GRADUAL DECREASE IN LOWER LEVEL RH LATER TONIGHT AND
ESPECIALLY FOR MONDAY WILL RESULT IN A RETURN TO VFR CONDITIONS.
&&
.MARINE...WITH NORTH WINDS STARTING TO INCREASE IN THE WAKE OF THE
ARCTIC FRONT WILL GO AHEAD AND START THE SMALL CRAFT WITH THE MID
AFTERNOON ISSUANCE. IN ADDITION EXPECTING A PERIOD OF HEAVY FREEZING
SPRAY TONIGHT INTO TUESDAY MORNING WITH THE GUSTY WINDS AND INFLUX
OF ARCTIC AIR. PRESSURE GRADIENT REMAINS TIGHT INTO TUESDAY MORNING.
WITH SURFACE RIDGE DRAWING CLOSER TUESDAY AFTERNOON WINDS WILL EASE
AND TURN A BIT MORE TO THE NORTHWEST.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 2 AM TO 10 AM CST TUESDAY FOR WIZ046-
047-051-052-056>060-062>072.
LM...HEAVY FREEZING SPRAY WARNING FROM 9 PM THIS EVENING TO NOON CST
TUESDAY FOR LMZ643>646.
SMALL CRAFT ADVISORY UNTIL 3 PM CST TUESDAY FOR LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...99
TUESDAY NIGHT THROUGH MONDAY...99