Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/03/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1115 AM MST SUN FEB 1 2015
.UPDATE...UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
IN THE WAKE OF AN EXITING LOW PRESSURE SYSTEM...AREAS OF FOG...
POTENTIALLY DENSE ACROSS THE SOUTH CENTRAL DESERTS...WILL BE
POSSIBLE THROUGH THE MORNING HOURS DUE TO ABUNDANT MOISTURE AND
CLEARING SKIES. HIGH PRESSURE WILL QUICKLY COVER THE AREA TODAY
BRINGING CLEARING SKIES...DRY WEATHER...AND WARMER TEMPERATURES. THE
DRY CONDITIONS WILL PERSIST THROUGH THE WEEK WHILE A WARMING TREND
ALLOWS FOR HIGHS TO REACH NEAR 80 DEGREES ACROSS THE LOWER DESERTS
BY THE END OF THE WORK WEEK.
&&
.DISCUSSION...
AFTER A RATHER WET COUPLE OF DAYS...WHICH HAS LEFT THE BOUNDARY
LAYER AND SOILS QUITE MOIST OVER SOUTH-CENTRAL AND SOUTHWEST
AZ...CLEAR SKIES EARLY THIS MORNING HAS ALLOWED DENSE FOG TO DEVELOP
OVER THE REGION. ALTHOUGH CLEAR SKIES ABOVE THIS FOG WILL ALLOW FOR
MAXIMUM SOLAR HEATING TODAY...IT APPEARS THAT BURN-OFF WILL TAKE
SOME TIME...WITH THE LATEST HRRR NOT SHOWING FULL CLEARING UNTIL
AROUND NOON...LIKELY DUE TO THE FACT THAT THE FOG LAYERS ARE RATHER
DEEP...WITH AIRCRAFT REPORTS INDICATING TOPS OF 700-1000FT AGL. ONCE
THE FOG DOES CLEAR...STILL EXPECTING MOSTLY CLEAR SKIES FOR THE REST
OF THE DAY AS HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION.
OTHER THEN EXTENDING THE DENSE FOG ADVISORY UNTIL NOON AND MAKING
MINOR ADJUSTMENTS TO THE HOURLY TEMP AND DEWPOINT GRIDS...CURRENT
INHERITED FORECASTS STILL LOOK GOOD...NO FURTHER UPDATES ARE PLANNED
AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LOW THAT BROUGHT WIDESPREAD PRECIPITATION TO THE CENTRAL
DESERTS DURING THE PAST COUPLE OF DAYS HAS FINALLY SHIFTED OFF TO
THE SOUTHEAST...ALLOWING A SUBSIDENT NELY FLOW ALOFT TO OVERSPREAD
THE AREA. STRONG SUBSIDENCE ALOFT HAS BROUGHT CONSIDERABLE CLEARING
TO SOUTH CENTRAL AZ...AND IR IMAGERY AT 2 AM SHOWED GENLY CLEAR
SKIES FROM PHOENIX WESTWARD. A FEW MID/HIGH CLOUDS PERSISTED WELL TO
THE SOUTH AND EAST OF CENTRAL PHOENIX. ALTHOUGH MOISTURE HAS STARTED
TO THIN A BIT AS SEEN BY THE LATEST SOUNDINGS WHICH SHOWED PWAT
VALUES OF 0.86 AT SAN DIEGO AND 0.74 INCHES AT TUS...BOUNDARY LAYER
MOISTURE REMAINED HIGH AFTER ALL OF THE RAIN THAT HAS RECENTLY
FALLEN. SURFACE DEWPOINTS OVER THE DESERTS WERE RUNNING MOSTLY IN
THE UPPER 40S TO AROUND 50 AND RH VALUES WERE 100 PERCENT OR CLOSE
TO IT ACROSS MUCH OF THE CENTRAL DESERTS. OBSERVED AND FORECAST
SOUNDINGS FOR THIS MORNING SHOWED A VERY FAVORABLE DENSE FOG PROFILE
AND SPOTTER REPORTS AS WELL AS WEBCAMS HAVE BEEN INDICATING DENSE
FOG FORMING ACROSS THE SOUTHEAST VALLEY AND ACROSS NW PINAL COUNTY.
AS SUCH A DENSE FOG ADVISORY HAS BEEN ISSUED FOR NWRN/NCNTRL PINAL
COUNTY AS WELL AS THE GREATER PHOENIX AREA THRU 10 AM THIS MORNING.
WE MAY HAVE TO EXPAND THE ADVISORY INTO WESTERN MARICOPA COUNTY
SHOULD FOG DEVELOP OR SPREAD WESTWARD INTO THAT AREA. OTHERWISE...
EXPECT FOG TO DISSIPATE LATER THIS MORNING LEAVING MOSTLY SUNNY
SKIES ACROSS THE CENTRAL DESERTS. UNDER MOSTLY SUNNY SKIES...HIGH
TEMPS WILL BE ABLE TO CLIMB A HANDFUL OF DEGREES AND APPROACH
SEASONAL NORMALS.
MODEL GUIDANCE REMAINS VERY CONSISTENT IN CALLING FOR DRY AND WARMER
CONDITIONS FOR THE ENTIRE WEEK...AS A STRONG UPPER LEVEL HIGH
PRESSURE RIDGE STEADILY BUILDS INTO THE DESERT SOUTHWEST. AS THE
RIDGE BUILDS...THERE WILL BE PERIODS OF HIGH CLOUDS SPREADING
THROUGH THE RIDGE AND ACROSS THE DESERTS...BUT OVERALL WE SHOULD SEE
MOSTLY SUNNY DAYS AND MOSTLY CLEAR NIGHTS. HIGH TEMPS ARE FORECAST
TO CLIMB INTO THE MID TO UPPER 70S BY TUESDAY...THEN RISE FURTHER
AND INTO THE UPPER 70S TO LOW 80S ACROSS THE WARMER DESERTS BY
FRIDAY. H5 HEIGHTS ARE FORECAST TO RISE IN EXCESS OF 585DM OVER THE
SOUTHWEST AZ AND SERN CA DESERTS BY THIS WEEKEND AND WE COULD SEE
HIGH TEMPS REACH INTO THE MID TO UPPER 80S ACROSS THE WARMER LOWER
DESERTS AS A RESULT. WE HAVE RAISED OUR FORECAST HIGH TEMPS 2-3
DEGREES FOR THE LATTER PORTION OF THE WEEK AS A RESULT OF INCREASED
CONFIDENCE IN THE VERY WARM FORECAST CONDITIONS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
FOG IS QUICKLY BURNING OFF AND EXPECTING IMPROVING VSBYS AND VFR
CONDITIONS BY 19-20Z. EXPECTING TO SEE SOME AFTERNOON CU DEVELOPMENT
AFTER 21Z...BUT COVERAGE SHOULD REMAIN FEW TO SCATTERED WITH BASES
AROUND 5-6K FEET. FOR WINDS...LIGHT DIURNALLY DRIVEN AT ALL SITES
WITH VERY LIGHT EAST WINDS EXPECTED MONDAY MORNING. THERE IS THE
POTENTIAL FOR ANOTHER ROUND OF FOG LATE SUNDAY NIGHT INTO MONDAY
MORNING...BUT NOT ANTICIPATING ANY DENSE FOG THIS TIME AND
CONFIDENCE IN OCCURRENCE IS STILL LOW. BEST TIME FRAME FOR ANY VSBY
IMPACTS AT TERMINALS WOULD BE BETWEEN 11Z-16Z.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO AVIATION IMPACTS FOR SOUTHEAST CALIFORNIA AS SKIES WILL REMAIN
CLEAR THROUGH MONDAY MORNING. SFC WINDS WILL RETAIN A LIGHT
NORTHERLY COMPONENT...THOUGH WILL BECOME VARIABLE AT TIMES AS THE
UNDER A WEAK PRESSURE GRADIENT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
WARMER TEMPERATURES ARE EXPECTED ACROSS THE REGION THIS WEEK ALONG
WITH DRIER AIR. DESPITE THIS...AFTERNOON HUMIDITIES WILL ONLY DROP
INTO THE 15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT
RECOVERIES EXPECTED. NO MAJOR WIND EVENTS ARE ANTICIPATED WITH WINDS
FOLLOWING THE TYPICAL DIURNAL PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...DENSE FOG ADVISORY UNTIL NOON TODAY FOR AZZ021>023-025>028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/CB
AVIATION...KUHLMAN
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
840 AM MST SUN FEB 1 2015
.SYNOPSIS...
IN THE WAKE OF AN EXITING LOW PRESSURE SYSTEM...AREAS OF FOG...
POTENTIALLY DENSE ACROSS THE SOUTH CENTRAL DESERTS...WILL BE
POSSIBLE THROUGH THE MORNING HOURS DUE TO ABUNDANT MOISTURE AND
CLEARING SKIES. HIGH PRESSURE WILL QUICKLY COVER THE AREA TODAY
BRINGING CLEARING SKIES...DRY WEATHER...AND WARMER TEMPERATURES. THE
DRY CONDITIONS WILL PERSIST THROUGH THE WEEK WHILE A WARMING TREND
ALLOWS FOR HIGHS TO REACH NEAR 80 DEGREES ACROSS THE LOWER DESERTS
BY THE END OF THE WORK WEEK.
&&
.DISCUSSION...
AFTER A RATHER WET COUPLE OF DAYS...WHICH HAS LEFT THE BOUNDARY
LAYER AND SOILS QUITE MOIST OVER SOUTH-CENTRAL AND SOUTHWEST
AZ...CLEAR SKIES EARLY THIS MORNING HAS ALLOWED DENSE FOG TO DEVELOP
OVER THE REGION. ALTHOUGH CLEAR SKIES ABOVE THIS FOG WILL ALLOW FOR
MAXIMUM SOLAR HEATING TODAY...IT APPEARS THAT BURN-OFF WILL TAKE
SOME TIME...WITH THE LATEST HRRR NOT SHOWING FULL CLEARING UNTIL
AROUND NOON...LIKELY DUE TO THE FACT THAT THE FOG LAYERS ARE RATHER
DEEP...WITH AIRCRAFT REPORTS INDICATING TOPS OF 700-1000FT AGL. ONCE
THE FOG DOES CLEAR...STILL EXPECTING MOSTLY CLEAR SKIES FOR THE REST
OF THE DAY AS HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION.
OTHER THEN EXTENDING THE DENSE FOG ADVISORY UNTIL NOON AND MAKING
MINOR ADJUSTMENTS TO THE HOURLY TEMP AND DEWPOINT GRIDS...CURRENT
INHERITED FORECASTS STILL LOOK GOOD...NO FURTHER UPDATES ARE PLANNED
AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LOW THAT BROUGHT WIDESPREAD PRECIPITATION TO THE CENTRAL
DESERTS DURING THE PAST COUPLE OF DAYS HAS FINALLY SHIFTED OFF TO
THE SOUTHEAST...ALLOWING A SUBSIDENT NELY FLOW ALOFT TO OVERSPREAD
THE AREA. STRONG SUBSIDENCE ALOFT HAS BROUGHT CONSIDERABLE CLEARING
TO SOUTH CENTRAL AZ...AND IR IMAGERY AT 2 AM SHOWED GENLY CLEAR
SKIES FROM PHOENIX WESTWARD. A FEW MID/HIGH CLOUDS PERSISTED WELL TO
THE SOUTH AND EAST OF CENTRAL PHOENIX. ALTHOUGH MOISTURE HAS STARTED
TO THIN A BIT AS SEEN BY THE LATEST SOUNDINGS WHICH SHOWED PWAT
VALUES OF 0.86 AT SAN DIEGO AND 0.74 INCHES AT TUS...BOUNDARY LAYER
MOISTURE REMAINED HIGH AFTER ALL OF THE RAIN THAT HAS RECENTLY
FALLEN. SURFACE DEWPOINTS OVER THE DESERTS WERE RUNNING MOSTLY IN
THE UPPER 40S TO AROUND 50 AND RH VALUES WERE 100 PERCENT OR CLOSE
TO IT ACROSS MUCH OF THE CENTRAL DESERTS. OBSERVED AND FORECAST
SOUNDINGS FOR THIS MORNING SHOWED A VERY FAVORABLE DENSE FOG PROFILE
AND SPOTTER REPORTS AS WELL AS WEBCAMS HAVE BEEN INDICATING DENSE
FOG FORMING ACROSS THE SOUTHEAST VALLEY AND ACROSS NW PINAL COUNTY.
AS SUCH A DENSE FOG ADVISORY HAS BEEN ISSUED FOR NWRN/NCNTRL PINAL
COUNTY AS WELL AS THE GREATER PHOENIX AREA THRU 10 AM THIS MORNING.
WE MAY HAVE TO EXPAND THE ADVISORY INTO WESTERN MARICOPA COUNTY
SHOULD FOG DEVELOP OR SPREAD WESTWARD INTO THAT AREA. OTHERWISE...
EXPECT FOG TO DISSIPATE LATER THIS MORNING LEAVING MOSTLY SUNNY
SKIES ACROSS THE CENTRAL DESERTS. UNDER MOSTLY SUNNY SKIES...HIGH
TEMPS WILL BE ABLE TO CLIMB A HANDFUL OF DEGREES AND APPROACH
SEASONAL NORMALS.
MODEL GUIDANCE REMAINS VERY CONSISTENT IN CALLING FOR DRY AND WARMER
CONDITIONS FOR THE ENTIRE WEEK...AS A STRONG UPPER LEVEL HIGH
PRESSURE RIDGE STEADILY BUILDS INTO THE DESERT SOUTHWEST. AS THE
RIDGE BUILDS...THERE WILL BE PERIODS OF HIGH CLOUDS SPREADING
THROUGH THE RIDGE AND ACROSS THE DESERTS...BUT OVERALL WE SHOULD SEE
MOSTLY SUNNY DAYS AND MOSTLY CLEAR NIGHTS. HIGH TEMPS ARE FORECAST
TO CLIMB INTO THE MID TO UPPER 70S BY TUESDAY...THEN RISE FURTHER
AND INTO THE UPPER 70S TO LOW 80S ACROSS THE WARMER DESERTS BY
FRIDAY. H5 HEIGHTS ARE FORECAST TO RISE IN EXCESS OF 585DM OVER THE
SOUTHWEST AZ AND SERN CA DESERTS BY THIS WEEKEND AND WE COULD SEE
HIGH TEMPS REACH INTO THE MID TO UPPER 80S ACROSS THE WARMER LOWER
DESERTS AS A RESULT. WE HAVE RAISED OUR FORECAST HIGH TEMPS 2-3
DEGREES FOR THE LATTER PORTION OF THE WEEK AS A RESULT OF INCREASED
CONFIDENCE IN THE VERY WARM FORECAST CONDITIONS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
FOG FORMATION WELL UNDERWAY ACROSS THE METRO AS OF 11Z AND KIWA HAS
BEEN VLIFR FOR SEVERAL HOURS ALREADY. SATELLITE INDICATING
DETERIORATING CONDITIONS IN THE NORTH/WEST VALLEY AND IT APPEARS
ITS ONLY A MATTER OF TIME BEFORE BOTH KPHX AND KSDL SEE FOG. GOING
TO INTRODUCE A PERIOD OF 1SM VSBYS AT BOTH LOCATIONS FROM APPROX
12Z-17Z TODAY. I EXPECT THE WORST CONDITIONS FROM DAYBREAK /14Z/
UNTIL MID MORNING WHEN BL MIXING SHOULD HELP BREAK THINGS UP.
CONDITIONS SHOULD IMPROVE RAPIDLY THROUGH THE AFTERNOON HOURS WITH
MINIMAL IMPACTS FORECAST BEYOND 20Z. AS FOR WINDS...LIGHT DIURNALLY
DRIVEN AT ALL SITES. VERY LIGHT EAST WINDS EXPECTED MONDAY MORNING.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
NO MAJOR AVIATION IMPACTS FOR SOUTHEAST CALIFORNIA AS SKIES RAPIDLY
CLEAR. SFC WINDS WILL RETAIN A LIGHT NORTHERLY COMPONENT...THOUGH
COULD BECOME VARIABLE AT TIME AS THE PRESSURE GRADIENT WEAKENS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
WARMER TEMPERATURES ARE EXPECTED ACROSS THE REGION THIS WEEK ALONG
WITH DRIER AIR. DESPITE THIS...AFTERNOON HUMIDITIES WILL ONLY DROP
INTO THE 15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT
RECOVERIES EXPECTED. NO MAJOR WIND EVENTS ARE ANTICIPATED WITH WINDS
FOLLOWING THE TYPICAL DIURNAL PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...DENSE FOG ADVISORY UNTIL NOON TODAY FOR AZZ021>023-025>028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/CB
AVIATION...LEINS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1029 PM MST SAT JAN 31 2015
.UPDATE...
ISSUED AT 809 PM MST SAT JAN 31 2015
UPDATED FORECAST TO ACCOUNT FOR RADAR TRENDS OVER EASTERN PLAINS
AN PRECIP DROPPING SOUTH TOWARDS THE PIKES PEAK REGION. ALSO
EXPIRING SNOW ADVISORIES FOR PARTS OF THE HIGH COUNTRY. /HODANISH
UPDATE ISSUED AT 447 PM MST SAT JAN 31 2015
FINE-TUNED FORECAST FOR LATEST RADAR TRENDS AND HRRR FCST. FIRST
BAND OF PRECIP WILL MOVE ACROSS THE REGION EARLY THIS EVENING
WITH ANOTHER BAND COMING ACROSS MAINLY THE PIKES PEAK REGION
TOWARDS MIDNIGHT. FIRST BAND ALREADY CLEARED C MTNS AND WILL
REMOVE SNOW ADVISORY FROM THIS REGION WITH THIS UPDATE.
UPDATE WILL BE ISSUED SHORTLY AFTER 5 PM. /HODANISH
/HODANISH
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 236 PM MST SAT JAN 31 2015
CURRENTLY...PRECIP EXPANDING ACROSS THE AREA AS LIFT INCREASES AHEAD
OF UPPER TROUGH DROPPING SOUTHWARD THROUGH THE NRN ROCKIES. SURFACE
COLD FRONT WAS ALONG THE PALMER DIVIDE AS OF 21Z...WITH PRECIP
EXPECTED TO EXPAND ALONG/BEHIND THE BOUNDARY INTO EARLY EVENING AS
IT DROPS SOUTH TOWARD THE NM BORDER. WARMER TEMPS HAVE HELD ON AHEAD
OF THE FRONT ALONG AND SOUTH OF THE ARKANSAS RIVER...AND EXPECT
PRECIP TO BEGIN AS RAIN BELOW ABOUT 6K FEET LATE THIS AFTERNOON.
FARTHER WEST..SNOW CONTINUES ACROSS THE HIGHER ELEVATIONS AND MOST
VALLEYS...THOUGH BACK EDGE OF STEADIER SNOW WAS ALREADY MOVING
TOWARD THE CENTRAL MOUNTAINS AS OF 21Z.
TONIGHT...LEFT CURRENT ROUND OF WINTER HIGHLIGHTS INTACT...THOUGH
WITH BACK EDGE OF SNOW DROPPING SOUTH OF I-70 ALREADY...CENTRAL
MOUNTAIN ADVISORY MAY NEED TO BE DROPPED EARLY WITH NEXT UPDATE.
ELSEWHERE...EXPECT A PERIOD OF SNOW OVER MOST MOUNTAINS AND HIGH
VALLEYS THROUGH THE EVENING...WITH FOCUS OF HEAVIER SNOW SHIFTING TO
THE EASTERN MOUNTAINS AS FLOW BECOMES WEAKLY UPSLOPE. HIGHER
PEAKS OF THE SANGRES/WETS/PIKES PEAK WILL SEE SOME MODEST (2-5 INCH)
ACCUMULATIONS THIS EVENING...WHILE VALLEYS SEE A QUICK INCH OR TWO.
PRECIP ON THE PLAINS BELOW ABOUT 6K FEET WILL START AS RAIN...WITH A
GRADUAL CHANGE OVER TO SNOW AFTER SUNSET AS COLDER AIR AT THE
SURFACE AND ALOFT SPREADS SOUTH. LATE CHANGEOVER AND WARM GROUND
WILL LIMIT ACCUMS ON THE PLAINS...THOUGH EL PASO COUNTY COULD SEE A
INCH OR TWO ONCE TEMPS DROP BELOW FREEZING AFTER SUNSET. PAST 04Z-
06Z...LIFT DECREASES OVER MOUNTAINS/WRN VALLEYS AS TROUGH DROPS
SOUTH...WITH SNOW FADING AWAY FAIRLY QUICKLY BY LATE EVENING.
EASTERN MOUNTAINS WILL LIKELY HOLD ON TO SNOW LONGER AS WEAK
UPSLOPE COMPONENT KEEPS AT LEAST SOME LIGHT SNOW GOING INTO SUN
MORNING. OVERNIGHT LOWS WILL DROP BELOW FREEZING MOST LOCATIONS AS
DRIER/COLDER AIR FILTERS SOUTH THROUGH THE NIGHT.
SUNDAY...STILL SOME LINGERING LIGHT SNOW ALONG/WEST OF I-25 IN THE
MORNING...GRADUALLY FADING TO FLURRIES IN THE AFTERNOON AS UPSLOPE
FADES AND UPPER JET SHIFTS INTO THE CENTRAL PLAINS. DESPITE SOME SUN
MANY AREAS BY AFTERNOON...CONTINUED COLD ADVECTION WILL KEEP TEMPS
FAIRLY COOL WITH MOST LOCATIONS IN THE 30S OR COLDER.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 236 PM MST SAT JAN 31 2015
MODELS CONTINUE TO HAVE DIFFERENCES IN THE MIDDLE OF THE EXTENDED
PERIOD WITH THE ECMWF HAVE BETTER ENSEMBLE SUPPORT THAN THE GFS
SOLUTION.
SUNDAY NIGHT THROUGH TUESDAY...THE UPPER PATTERN WILL FEATURE A
TROUGH MOVING OFF TO THE EAST WHILE AN UPPER RIDGE DEVELOPS ALONG
THE WEST COAST. THIS WILL PUT SOUTHERN COLORADO UNDER BROAD
NORTHWESTERLY FLOW ALOFT. SNOW WILL BE WINDING DOWN OVER THE
SOUTHERN SANGRE DE CRISTO MOUNTAINS SUNDAY EVENING WITH DRY
CONDITIONS EXPECTED ACROSS MOST OF THE REGION BY MONDAY MORNING.
THE EXCEPTION WILL BE THE CENTRAL MOUNTAINS. THE PERSISTENT
NORTHWESTERLY FLOW IS FAVORED OROGRAPHICALLY AND CONTINUOUS LIGHT
SNOW WILL PREVAIL OVER THE CENTRAL MOUNTAINS THROUGH TUESDAY
NIGHT. ACCUMULATIONS OF 3 TO 6 INCHES WITH LOCALLY HIGHER
AMOUNTS ARE POSSIBLE SUNDAY NIGHT THROUGH TUESDAY NIGHT. DRY
CONDITIONS WILL PREVAIL ACROSS THE EASTERN PLAINS. MIXING OF
NORTHWESTERLY FLOW WILL BRING WARMING TEMPERATURES TO THE LOWER
ELEVATIONS...WITH 50S FOR HIGHS ON MONDAY...AND 60S ON TUESDAY.
WEDNESDAY...MODELS CONTINUE TO STRUGGLE WITH THE NEXT WEATHER
SYSTEM EXPECTED TO REACH THE AREA ON WEDNESDAY. THE GFS IS THE
MOST AGGRESSIVE WITH THIS SHORTWAVE TROUGH...WHICH IS FORECAST TO
DROP SOUTH OUT OF THE NORTHERN ROCKIES. THE GFS DROPS A COLD
FRONT ACROSS EASTERN COLORADO AND DEVELOPS WIDESPREAD RAIN
CHANGING TO SNOW WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT BEFORE
CLEARING THE AREA BY THURSDAY MORNING. THE ECMWF...WHICH HAS
BETTER ENSEMBLE SUPPORT...IS MUCH DIFFERENT THAN THE GFS. IT TAKES
THE UPPER LEVEL SHORTWAVE TROUGH OUT OF MONTANA...AND BARELY CLIPS
NORTHEAST COLORADO AS IT TRACKS INTO THE CENTRAL PLAINS. IT ALSO
HAS A COLD FRONT BY WEDNESDAY EVENING OVER THE PLAINS...BUT DOES
NOT HAVE MUCH IN THE WAY OF PRECIPITATION ACROSS THE REGION. IT
HAS SNOW OVER THE CENTRAL MOUNTAINS...AND PERHAPS THE PALMER
DIVIDE WEDNESDAY NIGHT...BUT KEEPS THE EASTERN PLAINS DRY. FOR NOW
HAVE LOW POPS ACROSS THE PLAINS...BUT CONFIDENCE IS LOW AT THIS
TIME. TEMPERATURES ON WEDNESDAY WILL DEPEND ON FRONTAL TIMING WITH
40S TO LOWER 50S EXPECTED.
THURSDAY THROUGH SATURDAY...BROAD NORTHWESTERLY FLOW WILL
REDEVELOP ACROSS THE REGION AS HIGH PRESSURE OVER THE WEST MOVES
SLOWLY EASTWARD. LIGHT SNOW OVER THE CENTRAL MOUNTAINS IS FORECAST
TO DISSIPATE BY FRIDAY AS DRIER AIR ALOFT MOVES INTO THE AREA.
TEMPERATURES WILL ALSO REBOUND WITH 50S AND 60S BY FRIDAY AND
SATURDAY. MOZLEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1026 PM MST SAT JAN 31 2015
KCOS...COLD FRONT WILL MOVE THROUGH LATER TONIGHT. WE MAY SEE SOME
SNOW SHOWERS AND LOWER CIGS BETWEEN 07-11Z TONIGHT WITH SNOW AND
CLOUDS...OTHERWISE VFR EXPECTED THROUGH 02/06Z
KPUB...VFR NEXT 24H. MAY SEE SOME LIGHT BR THROUGH 08Z.
KALS...GUIDANCE SHOWS IT DRYING OUT TONIGHT BUT KALS CAN BE
PROBLEMATIC DUE TO THE VALLEY. FOR NOW WENT WITH TRENDS IN
GUIDANCE BUT DELAYED LOW CLOUDS GETTING OUT OF THE VALLEY UNTIL
LATER ON TONIGHT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ074-
075.
&&
$$
UPDATE...HODANISH
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
252 PM EST Sun Feb 1 2015
.Near Term [Through Today]...
Rain continues to spread into the western part of our area,
roughly on schedule with the consensus of high-resolution models.
As such, there are no substantial changes from the forecast edits
that were made this morning. The best rain chances should spread
east to the Apalachicola, to Tallahassee, to Tifton corridor in
the mid-to-late evening hours before exiting the eastern part of
our area later in the overnight or early Monday morning. There is
some marginal instability on the latest objective RAP analysis,
but it is mainly focused to the west of our area as of 19Z. This
should spread into the area overnight, so there will still be a
slight chance of a thunderstorm or two tonight. The WAA pattern in
advance of the surface cold front should hold temperatures
relatively steady in the low 60s overnight before beginning to
fall in the few hours before sunrise as the cold front arrives.
.Short Term [Tonight Through Tuesday]...
Cold front will be situated across the eastern half of the
forecast area by sunrise Monday morning, with showers ongoing
along and ahead of the boundary. The rain will end during the
morning, with skies clearing from west to east during the day.
Temperatures will vary widely across the area to start the day,
with mid 40s in the northwest and mid 60s in the southeast.
Temperatures will generally fall or remain steady through most of
the day as strong cold air advection kicks in behind the front.
Afternoon temperatures will range from the mid 40s in the
northwest to the mid 50s in the southeast.
Seasonably cool conditions are expected Monday night and Tuesday,
with lows near freezing and highs in the mid 50s to lower 60s.
Temperatures will moderate Tuesday night ahead of the next system.
At this time, it appears the rain will hold off until daylight on
Wednesday.
.Long Term [Tuesday Night Through Sunday]...
An upper low ejecting from the desert southwest will induce
cyclogenesis over the western Gulf early Wednesday morning. While
the upper low will deamplify as it is absorbed by a developing
large scale trough, the surface low will continue to move east
along the northern Gulf Coast through the day on Wednesday into
Thursday. Lift ahead of the upper trough as well as isentropic
lift in the lower levels will produce a broad area of rain across
the area from early Wednesday to early Thursday.
A cooler and drier airmass will move into the region late on
Thursday as the storm system exits. This will keep the weather
dry and slightly cooler than normal from Friday through the
weekend.
&&
.Aviation...
[Through 18Z Monday] We should see MVFR CIGS gradually develop
and spread east through the rest of the afternoon and early
evening, affecting all terminals as rain begins to move into the
area. S-SE winds may be gusty at times prior to 00Z. As some of
the steadier rain comes to an end overnight from west to east,
some IFR CIGS may develop before a cold front arrives to scour
them out around sunrise. Northwest winds behind the front tomorrow
may be gusty to between 20-30 knots as CIGS quickly improve to
VFR.
&&
.Marine...
Small Craft Advisory conditions will continue through Monday ahead
of (and behind) the approaching cold front. Winds will shift from
southwest to northwest as the front passes. Following a brief lull
early on Tuesday, easterly winds will return to exercise caution
levels and continue into Thursday. Strong offshore flow will be
possible again by Friday in the wake of another front.
&&
.Fire Weather...
A wetting rain is expected today into tonight for the entire
region. Red Flag conditions are not expected for the next week.
&&
.Hydrology...
The first system for this afternoon through Monday morning is
expected to produce mainly less than 1" of rain across the area,
although a couple of isolated amounts heavier than 1" are possible
across portions of southeast Alabama and the Florida panhandle.
The second system during the Wednesday-Thursday time frame is
expected to produce a bit more rainfall with a general 1-2"
possible. When combined with the rains from the first system and
already above average stream flows, a few rivers may approach minor
flood stage late in the week. At this time, the progressive nature
of the pattern is expected to keep rainfall amounts from getting
high enough to produce more significant flooding.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 58 64 32 58 40 / 80 50 0 0 10
Panama City 54 62 34 55 44 / 80 30 0 0 10
Dothan 48 50 30 55 39 / 80 20 0 0 10
Albany 52 58 29 55 36 / 80 40 0 0 10
Valdosta 58 63 32 58 41 / 80 60 0 0 10
Cross City 60 67 30 62 43 / 70 60 0 0 10
Apalachicola 59 65 36 56 46 / 70 40 0 0 10
&&
.TAE Watches/Warnings/Advisories...
FL...RIP CURRENT RISK through Monday evening for Coastal Bay-Coastal
Franklin-Coastal Gulf-South Walton.
GA...None.
AL...None.
GM...Small Craft Advisory until 10 PM EST Monday for Coastal waters
From Ochlockonee River to Apalachicola FL out to 20 NM-
Coastal waters from Apalachicola to Destin FL out 20 NM-
Waters from Suwannee River to Apalachicola FL from 20 to 60
NM-Waters from Apalachicola to Destin FL from 20 to 60 NM.
&&
$$
NEAR TERM...LAMERS
SHORT TERM...CAMP
LONG TERM...CAMP
AVIATION...LAMERS
MARINE...CAMP
FIRE WEATHER...MCDERMOTT
HYDROLOGY...DVD
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NWS MELBOURNE FL
908 AM EST SUN FEB 1 2015
.DISCUSSION...
915 MHZ DATA FROM THE XMR AREA NETWORK SHOWS SLY COMPONENT FLOW HAS
BEEN IN PLACE BLO 3K FT FOR AROUND 7 HRS. THE MORNING SOUNDING FROM
XMR AND A REVIEW OF GPS SATELLITE DERIVED DATA INDICATE ONLY A
SLIGHT INCREASE IN PWAT THIS MORNING. PRIMARY OPEN CELL STRATO CU
OVER THE ATLC WATERS IS NOT EXPECTED TO PRODUCE MORE THAN WEAK RADAR
RETURNS OVER THE MARINE AREA THE REMAINDER OF THE AFTN. A DRY
FORECAST IS ALSO SUPPORTED BY THE LTST REGIONAL HRRR SOLN.
THE SURFACE HIGH PUSHING OFF OFFSHORE INTO THE SE ATLANTIC CST
WILL VEER WINDS TO THE SOUTHEAST. WINDS WILL INCREASE UP TO 10 TO 15
MPH WITH BREEZY CONDS ANTICIPATED ALONG THE TREASURE COAST.
SCATTERED MARINE STRATOCU WILL MOVE ONSHORE AND INLAND THROUGH THE
REMAINDER OF DAY WITH SKIES PARTLY SUNNY AND HIGHS REACHING THE LOW
TO MID 70S.
WINDS BECOME MORE SOUTHERLY INTO TONIGHT WITH MOISTURE INCREASING
AHEAD OF APPROACHING COLD FRONT ACROSS THE SOUTHEAST. MAY SEE A FEW
SHOWERS NORTH OF ORLANDO LATE TONIGHT AND OVER THE COASTAL WATERS.
OTHERWISE EXPECTING DRY CONDS WITH INCREASING CLOUD COVER OVERNIGHT.
LOWS WILL BE ABOVE NORMAL IN THE UPPER 50S TO LOW 60S.
&&
.AVIATION...(PREV DISC) VFR CONDS EXPECTED NEXT 24 HOURS. LOW LEVEL
ONSHORE WINDS WILL CONTINUE TO TRANSPORT SCT-BKN MARINE STRATOCU
ONSHORE WITH ANY BRIEF CIGS AOA 4K FT. SOUTHEAST WINDS 10-15 KTS
14Z WITH HIGHER GUSTS AT TIMES ALONG THE COAST. MAY NEED TO ADD A
PERIOD OF LLWS LATE TONIGHT THROUGH DAYBREAK MONDAY ACROSS NRN
TERMINALS DUE TO RAPIDLY INCREASING LOW LEVEL S/SW WINDS UP TO
AROUND 35 KTS AHEAD OF THE FRONT.
&&
.MARINE...
MODERATE TO FRESH ONSHORE BREEZE PERSISTS THROUGH THIS AFTERNOON
WITH SOUTHEAST WINDS. SEAS UP TO 6 FEET OVER THE GULF STREAM REQUIRE
CAUTION STMTS SOUTH OF THE CAPE.
WIND SPEEDS THEN CONTINUE TO INCREASE AS THEY BECOME MORE SOUTHERLY
INTO TONIGHT WITH BOATING CONDITIONS BECOMING HAZARDOUS OVER THE
OFFSHORE WATERS. WILL ISSUE A SCA STARTING OFFSHORE OF VOLUSIA
COUNTY LATE THIS EVENING...EXPANDING SOUTHWARD OVER THE OFFSHORE
WATERS LATE TONIGHT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 4 AM EST TUESDAY FOR
WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM
OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET 20 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST MONDAY
FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY
LINE 20 TO 60 NM OFFSHORE.
&&
$$
JP/TES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
200 PM CST SUN FEB 1 2015
.UPDATE...
WE HAVE INCREASED SNOWFALL AMOUNTS SOME THIS AFTERNOON...ESPECIALLY
ACROSS NORTHERN ILLINOIS AND FAR NORTHWESTERN INDIANA. A VERY
IMPRESSIVE SYSTEM CONTINUES TO DEVELOP ACROSS THE CENTRAL CONUS THIS
MORNING IN RESPONSE TO A STRONG PV ANOMALY OVER THE CENTRAL PLAINS.
AS THIS STORM CONTINUES TO INTENSIFY THIS AFTERNOON...MODEL GUIDANCE
SUGGESTS THAT A BAND OF STRONG FRONTOGENESIS WILL DEVELOP IN AN
EMERGING DEFORMATION ZONE ASSOCIATED WITH THE 700 MB LOW...RIGHT
ACROSS NORTHERN ILLINOIS. THIS ALSO LOOKS TO OCCUR DURING THE
PERIOD OF BEST STRONG MID/UPPER LEVEL Q-VECTOR DIVERGENCE
ASSOCIATED WITH THE MID/UPPER LEVEL SYSTEM. ALL IN ALL THIS POINTS
TO STRONG DYANAMICS SUPPORTIVE OF PERIODS OF HEAVY SNOW THROUGH
THE DAY TODAY...AND LINGERING THIS EVENING. IT APPEARS THE
HEAVIEST AMOUNTS WILL EXCEED A FOOT IN MANY AREAS...WITH A FOOT
AND A HALF NOT OUT OF THE QUESTION FOR NORTHERN ILLINOIS.
THE OTHER CONCERN IS BLIZZARD CONDITIONS...WE ARE UPGRADING THE REST
OF NORTH CENTRAL ILLINOIS TO A BLIZZARD WARNING. NORTHEASTERLY
WINDS WILL ONLY INCREASE THROUGH THE AFTERNOON...WITH GUSTS
POTENTIAL UP AROUND 40 KT AT TIMES GIVEN THE STRONG GRADIENT SETTING
UP ON THE BACK SIDE OF THIS SYSTEM. THIS HAS ME SERIOUSLY CONCERNED
THAT AS THE SNOW CONTINUES TO BECOME MORE POWDERY THROUGH THE
DAY...THAT WHITE OUT CONDITIONS WILL BE OBSERVED ACROSS NORTHERN
ILLINOIS. THE OTHER CONCERN IS FOR DOWNED TREE BRANCHES AND POWER
LINES. THE SNOW THAT HAS FALLEN THUS FAR ACROSS THE AREA HAS BEEN A
STICKY WET SNOW AND HAS PRODUCED SIGNIFICANT ACCUMULATIONS ON TREES
AND POWER LINES. THE INCREASING WINDS COULD BRING DOWN POWER
LINES...LEADING TO SOME ISOLATED POWER OUTAGES.
NEW UPDATES SHOULD BE OUT SHORTLY.
KJB
&&
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
118 PM CST
MONDAY THROUGH MONDAY NIGHT...
LOW PRESSURE WILL CONTINUE TO DEPART THE REGION TO THE EAST...WITH
ANTI-CYCLONIC FLOW REPLACING IT OVER THE FORECAST AREA FOR MON.
LONGWAVE FLOW PATTERN CONTINUES TO BE IN A SOMEWHAT NORTHWEST
ORIENTATION. THIS COUPLED WITH THE SFC RIDGE CENTER POSITIONED
JUST SOUTH OF THE CWFA WILL KEEP WINDS GENERALLY FROM THE
WEST/NORTHWEST. ENOUGH DRY AIR SHUD MIX DOWN TO THE SFC AND ERODE
THE BULK OF THE CLOUDS...HOWEVER NOT TOO CONFIDENT THAT CLEAR
SKIES WILL LINGER VERY LONG. THE FLOW WILL REMAIN PROGRESSIVE AND
HELP TO PUSH THE SFC RIDGE EAST/SOUTHEAST OF THE AREA BY LATE MON
NGT.
THIS WILL SETUP A WEAK MID-LVL WAVE SLIDING SOUTHEAST ACROSS THE
NORTHERN PLAINS TO ARRIVE LATE MON NGT IN THE FAR WESTERN CWFA. LLVL
FLOW WILL TURN SOUTHWESTERLY AND COULD KEEP SOME DRY AIR LOCKED IN
LONG ENOUGH TO KEEP ANY PRECIP WEST OF THE FORECAST AREA UNTIL LATE
MON NGT.
HIGHS MON WILL STRUGGLE TO WARM DESPITE THE THINNING SOLAR
SHIELDING...WITH TEMPS GENERALLY IN THE LOW/MID TEENS. THEN MON NGT
TEMPS ALOFT WILL EASILY RADIATE WITH LGT WINDS AND THIN CLOUD COVER.
FRESH SNOW PACK WILL LIKELY HELP TEMPS TO COOL INTO THE SINGLE
DIGITS ABOVE ZERO. WITH CLOUDS RETURNING LATE MON NGT FROM A WEAK
MID-LVL SYSTEM...TEMPS COULD RISE A DEGREE OR TWO AFTER
MIDNIGHT/EARLY TUE.
CURRENT EXPECTATION IS THAT ANY ACCUMULATIONS MON NGT WOULD BE LESS
THAN ONE HALF INCH.
TUESDAY THROUGH WEDNESDAY...
WITH A MID-LVL WAVE PIVOTING EAST OVERHEAD TUE MORNING...LLVL FLOW
WILL REMAIN SOUTHWESTERLY WITH SOME WEAK WARM AIR ADVECTING INTO THE
FORECAST AREA. TEMPS SHUD WARM INTO THE 20S TUE...AND WITH A GOOD
PUSH OF WARM AIR ADVECTION IN THE SOUTHERN TIER OF COUNTIES...TEMPS
COULD TAG 30 DEGREES TUE AFTN.
500MB TROUGH AXIS IS PROGGED TO SEND YET ANOTHER MID-LVL WAVE DIVING
SOUTHEAST ACROSS THE NORTHERN PLAINS TUE MORNING. GUIDANCE HAS
CONTINUED TO PROG THE ARRIVAL OF THIS FEATURE INTO THE CWFA TUE NGT.
FORCING APPEARS TO BE RATHER WEAK...HOWEVER ENOUGH MOISTURE AND LIFT
COULD EASILY PRODUCE SOME LGT SNOW ONCE AGAIN LATE TUE NGT. AT THIS
TIME IT WOULD APPEAR AROUND 1 INCH OF SNOW.
CONSIDERABLE CLOUDINESS TUE NGT WILL HELP TO HOLD TEMPS UP...WITH
OVERNIGHT LOWS IN THE UPR TEENS TO MID 20S.
SOME LINGERING LGT SNOW WED MORNING...WITH FLOW STARTING TO FLATTEN
BY MIDDAY WED. AS THE LOW LIFTS NORTHEAST WED MORNING ACROSS LOWER
MI...A TRAILING BOUNDARY WILL SLOWLY SAG SOUTH ACROSS THE WESTERN
GREAT LAKES AND MID-MISSOURI VALLEY. A WEAK WAVE WILL TRY TO DEVELOP
OVER THE CENTRAL PLAINS EARLY WED...AND COULD BRING ADDTL LGT PRECIP
BACK INTO THE FAR WEST/SOUTHWEST CWFA LATE WED AFTN.
WEDNESDAY NIGHT THROUGH SATURDAY...
ENSEMBLES CONTINUE THE THEME OF AN ACTIVE FLOW...WITH TROUGHING
GENERALLY OVER THE GREAT LAKES REGION AND RIDGING REMAINING OVER
WESTERN CANADA. THERE IS SOME WEAK FLATTENING IN THE LONGWAVE
PATTERN THUR...BUT THIS APPEARS TO BE ONLY FOR ONE PERIOD.
THEN ENSEMBLES ARE BEGINNING TO SUGGEST BROAD RIDGING WILL DEVELOP
ACROSS THE SOUTHWEST CONUS...WHICH COULD SHIFT THE NORTHWEST FLOW
ORIENTATION TO THE NORTHEAST. ROBUST THERMAL TROUGH SWINGS OVER THE
REGION THUR...BRINGING MUCH COOLER AIR BACK WITH HIGHS IN THE SINGLE
DIGITS TO LOW TEENS. THUR NGT TEMPS COULD THEN DROP BELOW ZERO.
THEN FOR THE START OF THE UPCOMING WEEKEND TEMPS COULD WARM BACK
INTO THE LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SNOW THROUGH TONIGHT. LIGHT LAKE EFFECT SNOW EARLY MONDAY MAINLY
FOR MDW. PREVAILING VIS AT OR UNDER 1SM THROUGH THIS EVENING.
* NELY WINDS GUSTING TO 30-35 KT LATE THIS AFTERNOON/EARLY
EVENING.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30 KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
STEADY SNOWFALL CONTINUES THROUGH THE AFTERNOON AND EVENING. THE
SNOW HAS BEEN WET TO THIS POINT...BUT FROM NORTH TO SOUTH IT WILL
SHIFT TO A DRIER SNOW AS THE AFTERNOON AND EVENING GO ON.
VISIBILITIES HAVE BEEN LARGELY STEADY AROUND 1/2 MILE...AND WHILE
FLUCTUATIONS IN THIS WILL OCCUR FROM TIME TO TIME...EXPECT 1/2 TO
3/4 VSBYS TO GENERALLY BE THE RULE. AS THE WINDS RAMP UP LATER THIS
AFTERNOON AND EVENING...FEEL THAT THERE WILL BE OCCASIONAL 1/4 MILE
VISIBILITIES AS THE SNOW GETS A BIT MORE BLOWABLE...BUT STILL NOT
CONFIDENT IN THIS CONDITION PREVAILING. WILL HAVE TO MONITOR AS THE
WINDS RAMP UP. IF THIS WERE TO OCCUR...IT WOULD BE THE LATE
AFTERNOON AND EARLY EVENING PERIOD WHEN THE SURFACE LOW MOVES A BIT
FARTHER NORTH AND EAST. THINK THAT THE 22Z-02Z TIME FRAME WOULD BE
THE BEST BET FOR THIS. WINDS HOLD IN THE 050 DIRECTION THEN BACK
THROUGH THE EVENING TO 020 BY MID EVENING...THEN NNW OVERNIGHT.
SHOULD SEE SOME SLIGHTY IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL
FROM 4Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND. EXPECT LIGHT LAKE EFFECT SNOW SHOWERS OVERNIGHT.
MOST TERMINALS EXCEPT MDW AND GYY SHOULD BE DRY BY DAYBREAK WITH A
WEAKENING WESTERLY WIND.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
135 PM CST
LOW PRESSURE HAS BEEN SLOW TO LIFT NORTHEAST ACROSS THE OHIO
VALLEY...REACHING EAST CENTRAL IL BY EARLY THIS AFTERNOON. THIS
LOW CONTINUES TO DEEPEN AND WILL ALLOW FOR GALES TO INCREASE FROM
35 KT TO LIKELY CLOSER TO 40 KT. THE FAR NORTHERN PORTIONS OF LAKE
MICHIGAN MAY STRUGGLE TO SEE THE STRONGER GRADIENT DEVELOP AND
STRONGER GALES...BUT THE EXPECTATION IS THAT GALES WILL EVENTUALLY
REACH THE NORTHERN PORTIONS LATER THIS EVENING. WITH MUCH COLDER
AIR SLIDING ACROSS THE LAKE WITH GALE CONDITIONS...HEAVY FREEZING
SPRAY WILL BE LIKELY. LOW PRESSURE WILL THEN SLIDE NORTHEAST LATE
TONIGHT...AND THIS WILL ALLOW THE GRADIENT TO STEADILY RELAX
OVERNIGHT. THIS WILL GALES/FREEZING SPRAY TO COME TO AN END LATE
TONIGHT. BROAD HIGH PRESSURE WILL BUILD IN EARLY MONDAY...BRINGING
MUCH LIGHTER WINDS TO LAKE MICHIGAN.
THE FLOW REMAINS RELATIVELY ACTIVE...WITH THE HIGH PRESSURE
QUICKLY SLIDING EAST MONDAY EVENING AND FLOW TURNING
SOUTHWESTERLY. THE GRADIENT BEGINS TO INCREASE LATE MONDAY NIGHT
INTO TUESDAY...BUT AT THIS TIME IT APPEARS WINDS WILL REMAIN
BETWEEN 10-20KT POSSIBLY UP TO 25KT.
A SERIES OF LOW PRESSURE SYSTEMS WILL CONTINUE TO FEED FROM WEST
TO EAST ACROSS LAKE MICHIGAN THROUGH MID-WEEK...BUT AT THIS TIME
THE SYSTEMS ARE NOT EXPECTED TO BE STRONG.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
119 PM CST SUN FEB 1 2015
.UPDATE...
WE HAVE INCREASED SNOWFALL AMOUNTS SOME THIS AFTERNOON...ESPECIALLY
ACROSS NORTHERN ILLINOIS AND FAR NORTHWESTERN INDIANA. A VERY
IMPRESSIVE SYSTEM CONTINUES TO DEVELOP ACROSS THE CENTRAL CONUS THIS
MORNING IN RESPONSE TO A STRONG PV ANOMALY OVER THE CENTRAL PLAINS.
AS THIS STORM CONTINUES TO INTENSIFY THIS AFTERNOON...MODEL GUIDANCE
SUGGESTS THAT A BAND OF STRONG FRONTOGENESIS WILL DEVELOP IN AN
EMERGING DEFORMATION ZONE ASSOCIATED WITH THE 700 MB LOW...RIGHT
ACROSS NORTHERN ILLINOIS. THIS ALSO LOOKS TO OCCUR DURING THE
PERIOD OF BEST STRONG MID/UPPER LEVEL Q-VECTOR DIVERGENCE
ASSOCIATED WITH THE MID/UPPER LEVEL SYSTEM. ALL IN ALL THIS POINTS
TO STRONG DYANAMICS SUPPORTIVE OF PERIODS OF HEAVY SNOW THROUGH
THE DAY TODAY...AND LINGERING THIS EVENING. IT APPEARS THE
HEAVIEST AMOUNTS WILL EXCEED A FOOT IN MANY AREAS...WITH A FOOT
AND A HALF NOT OUT OF THE QUESTION FOR NORTHERN ILLINOIS.
THE OTHER CONCERN IS BLIZZARD CONDITIONS...WE ARE UPGRADING THE REST
OF NORTH CENTRAL ILLINOIS TO A BLIZZARD WARNING. NORTHEASTERLY
WINDS WILL ONLY INCREASE THROUGH THE AFTERNOON...WITH GUSTS
POTENTIAL UP AROUND 40 KT AT TIMES GIVEN THE STRONG GRADIENT SETTING
UP ON THE BACK SIDE OF THIS SYSTEM. THIS HAS ME SERIOUSLY CONCERNED
THAT AS THE SNOW CONTINUES TO BECOME MORE POWDERY THROUGH THE
DAY...THAT WHITE OUT CONDITIONS WILL BE OBSERVED ACROSS NORTHERN
ILLINOIS. THE OTHER CONCERN IS FOR DOWNED TREE BRANCHES AND POWER
LINES. THE SNOW THAT HAS FALLEN THUS FAR ACROSS THE AREA HAS BEEN A
STICKY WET SNOW AND HAS PRODUCED SIGNIFICANT ACCUMULATIONS ON TREES
AND POWER LINES. THE INCREASING WINDS COULD BRING DOWN POWER
LINES...LEADING TO SOME ISOLATED POWER OUTAGES.
NEW UPDATES SHOULD BE OUT SHORTLY.
KJB
&&
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
118 PM CST
MONDAY THROUGH MONDAY NIGHT...
LOW PRESSURE WILL CONTINUE TO DEPART THE REGION TO THE EAST...WITH
ANTI-CYCLONIC FLOW REPLACING IT OVER THE FORECAST AREA FOR MON.
LONGWAVE FLOW PATTERN CONTINUES TO BE IN A SOMEWHAT NORTHWEST
ORIENTATION. THIS COUPLED WITH THE SFC RIDGE CENTER POSITIONED
JUST SOUTH OF THE CWFA WILL KEEP WINDS GENERALLY FROM THE
WEST/NORTHWEST. ENOUGH DRY AIR SHUD MIX DOWN TO THE SFC AND ERODE
THE BULK OF THE CLOUDS...HOWEVER NOT TOO CONFIDENT THAT CLEAR
SKIES WILL LINGER VERY LONG. THE FLOW WILL REMAIN PROGRESSIVE AND
HELP TO PUSH THE SFC RIDGE EAST/SOUTHEAST OF THE AREA BY LATE MON
NGT.
THIS WILL SETUP A WEAK MID-LVL WAVE SLIDING SOUTHEAST ACROSS THE
NORTHERN PLAINS TO ARRIVE LATE MON NGT IN THE FAR WESTERN CWFA. LLVL
FLOW WILL TURN SOUTHWESTERLY AND COULD KEEP SOME DRY AIR LOCKED IN
LONG ENOUGH TO KEEP ANY PRECIP WEST OF THE FORECAST AREA UNTIL LATE
MON NGT.
HIGHS MON WILL STRUGGLE TO WARM DESPITE THE THINNING SOLAR
SHIELDING...WITH TEMPS GENERALLY IN THE LOW/MID TEENS. THEN MON NGT
TEMPS ALOFT WILL EASILY RADIATE WITH LGT WINDS AND THIN CLOUD COVER.
FRESH SNOW PACK WILL LIKELY HELP TEMPS TO COOL INTO THE SINGLE
DIGITS ABOVE ZERO. WITH CLOUDS RETURNING LATE MON NGT FROM A WEAK
MID-LVL SYSTEM...TEMPS COULD RISE A DEGREE OR TWO AFTER
MIDNIGHT/EARLY TUE.
CURRENT EXPECTATION IS THAT ANY ACCUMULATIONS MON NGT WOULD BE LESS
THAN ONE HALF INCH.
TUESDAY THROUGH WEDNESDAY...
WITH A MID-LVL WAVE PIVOTING EAST OVERHEAD TUE MORNING...LLVL FLOW
WILL REMAIN SOUTHWESTERLY WITH SOME WEAK WARM AIR ADVECTING INTO THE
FORECAST AREA. TEMPS SHUD WARM INTO THE 20S TUE...AND WITH A GOOD
PUSH OF WARM AIR ADVECTION IN THE SOUTHERN TIER OF COUNTIES...TEMPS
COULD TAG 30 DEGREES TUE AFTN.
500MB TROUGH AXIS IS PROGGED TO SEND YET ANOTHER MID-LVL WAVE DIVING
SOUTHEAST ACROSS THE NORTHERN PLAINS TUE MORNING. GUIDANCE HAS
CONTINUED TO PROG THE ARRIVAL OF THIS FEATURE INTO THE CWFA TUE NGT.
FORCING APPEARS TO BE RATHER WEAK...HOWEVER ENOUGH MOISTURE AND LIFT
COULD EASILY PRODUCE SOME LGT SNOW ONCE AGAIN LATE TUE NGT. AT THIS
TIME IT WOULD APPEAR AROUND 1 INCH OF SNOW.
CONSIDERABLE CLOUDINESS TUE NGT WILL HELP TO HOLD TEMPS UP...WITH
OVERNIGHT LOWS IN THE UPR TEENS TO MID 20S.
SOME LINGERING LGT SNOW WED MORNING...WITH FLOW STARTING TO FLATTEN
BY MIDDAY WED. AS THE LOW LIFTS NORTHEAST WED MORNING ACROSS LOWER
MI...A TRAILING BOUNDARY WILL SLOWLY SAG SOUTH ACROSS THE WESTERN
GREAT LAKES AND MID-MISSOURI VALLEY. A WEAK WAVE WILL TRY TO DEVELOP
OVER THE CENTRAL PLAINS EARLY WED...AND COULD BRING ADDTL LGT PRECIP
BACK INTO THE FAR WEST/SOUTHWEST CWFA LATE WED AFTN.
WEDNESDAY NIGHT THROUGH SATURDAY...
ENSEMBLES CONTINUE THE THEME OF AN ACTIVE FLOW...WITH TROUGHING
GENERALLY OVER THE GREAT LAKES REGION AND RIDGING REMAINING OVER
WESTERN CANADA. THERE IS SOME WEAK FLATTENING IN THE LONGWAVE
PATTERN THUR...BUT THIS APPEARS TO BE ONLY FOR ONE PERIOD.
THEN ENSEMBLES ARE BEGINNING TO SUGGEST BROAD RIDGING WILL DEVELOP
ACROSS THE SOUTHWEST CONUS...WHICH COULD SHIFT THE NORTHWEST FLOW
ORIENTATION TO THE NORTHEAST. ROBUST THERMAL TROUGH SWINGS OVER THE
REGION THUR...BRINGING MUCH COOLER AIR BACK WITH HIGHS IN THE SINGLE
DIGITS TO LOW TEENS. THUR NGT TEMPS COULD THEN DROP BELOW ZERO.
THEN FOR THE START OF THE UPCOMING WEEKEND TEMPS COULD WARM BACK
INTO THE LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SNOW THROUGH TONIGHT. LIGHT LAKE EFFECT SNOW EARLY MONDAY MAINLY
FOR MDW. PREVAILING VIS AT OR UNDER 1SM THROUGH THIS EVENING.
* NELY WINDS GUSTING TO 30-35 KT LATE THIS AFTERNOON/EARLY
EVENING.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30 KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
STEADY SNOWFALL CONTINUES THROUGH THE AFTERNOON AND EVENING. THE
SNOW HAS BEEN WET TO THIS POINT...BUT FROM NORTH TO SOUTH IT WILL
SHIFT TO A DRIER SNOW AS THE AFTERNOON AND EVENING GO ON.
VISIBILITIES HAVE BEEN LARGELY STEADY AROUND 1/2 MILE...AND WHILE
FLUCTUATIONS IN THIS WILL OCCUR FROM TIME TO TIME...EXPECT 1/2 TO
3/4 VSBYS TO GENERALLY BE THE RULE. AS THE WINDS RAMP UP LATER THIS
AFTERNOON AND EVENING...FEEL THAT THERE WILL BE OCCASIONAL 1/4 MILE
VISIBILITIES AS THE SNOW GETS A BIT MORE BLOWABLE...BUT STILL NOT
CONFIDENT IN THIS CONDITION PREVAILING. WILL HAVE TO MONITOR AS THE
WINDS RAMP UP. IF THIS WERE TO OCCUR...IT WOULD BE THE LATE
AFTERNOON AND EARLY EVENING PERIOD WHEN THE SURFACE LOW MOVES A BIT
FARTHER NORTH AND EAST. THINK THAT THE 22Z-02Z TIME FRAME WOULD BE
THE BEST BET FOR THIS. WINDS HOLD IN THE 050 DIRECTION THEN BACK
THROUGH THE EVENING TO 020 BY MID EVENING...THEN NNW OVERNIGHT.
SHOULD SEE SOME SLIGHTY IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL
FROM 4Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND. EXPECT LIGHT LAKE EFFECT SNOW SHOWERS OVERNIGHT.
MOST TERMINALS EXCEPT MDW AND GYY SHOULD BE DRY BY DAYBREAK WITH A
WEAKENING WESTERLY WIND.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1230 PM CST SUN FEB 1 2015
.UPDATE...
WE HAVE INCREASED SNOWFALL AMOUNTS SOME THIS AFTERNOON...ESPECIALLY
ACROSS NORTHERN ILLINOIS AND FAR NORTHWESTERN INDIANA. A VERY
IMPRESSIVE SYSTEM CONTINUES TO DEVELOP ACROSS THE CENTRAL CONUS THIS
MORNING IN RESPONSE TO A STRONG PV ANOMALY OVER THE CENTRAL PLAINS.
AS THIS STORM CONTINUES TO INTENSIFY THIS AFTERNOON...MODEL GUIDANCE
SUGGESTS THAT A BAND OF STRONG FRONTOGENESIS WILL DEVELOP IN AN
EMERGING DEFORMATION ZONE ASSOCIATED WITH THE 700 MB LOW...RIGHT
ACROSS NORTHERN ILLINOIS. THIS ALSO LOOKS TO OCCUR DURING THE
PERIOD OF BEST STRONG MID/UPPER LEVEL Q-VECTOR DIVERGENCE
ASSOCIATED WITH THE MID/UPPER LEVEL SYSTEM. ALL IN ALL THIS POINTS
TO STRONG DYANAMICS SUPPORTIVE OF PERIODS OF HEAVY SNOW THROUGH
THE DAY TODAY...AND LINGERING THIS EVENING. IT APPEARS THE
HEAVIEST AMOUNTS WILL EXCEED A FOOT IN MANY AREAS...WITH A FOOT
AND A HALF NOT OUT OF THE QUESTION FOR NORTHERN ILLINOIS.
THE OTHER CONCERN IS BLIZZARD CONDITIONS...WE ARE UPGRADING THE REST
OF NORTH CENTRAL ILLINOIS TO A BLIZZARD WARNING. NORTHEASTERLY
WINDS WILL ONLY INCREASE THROUGH THE AFTERNOON...WITH GUSTS
POTENTIAL UP AROUND 40 KT AT TIMES GIVEN THE STRONG GRADIENT SETTING
UP ON THE BACK SIDE OF THIS SYSTEM. THIS HAS ME SERIOUSLY CONCERNED
THAT AS THE SNOW CONTINUES TO BECOME MORE POWDERY THROUGH THE
DAY...THAT WHITE OUT CONDITIONS WILL BE OBSERVED ACROSS NORTHERN
ILLINOIS. THE OTHER CONCERN IS FOR DOWNED TREE BRANCHES AND POWER
LINES. THE SNOW THAT HAS FALLEN THUS FAR ACROSS THE AREA HAS BEEN A
STICKY WET SNOW AND HAS PRODUCED SIGNIFICANT ACCUMULATIONS ON TREES
AND POWER LINES. THE INCREASING WINDS COULD BRING DOWN POWER
LINES...LEADING TO SOME ISOLATED POWER OUTAGES.
NEW UPDATES SHOULD BE OUT SHORTLY.
KJB
&&
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SNOW THROUGH TONIGHT. LIGHT LAKE EFFECT SNOW EARLY MONDAY MAINLY
FOR MDW. PREVAILING VIS AT OR UNDER 1SM THROUGH THIS EVENING.
* NELY WINDS GUSTING TO 30-35 KT LATE THIS AFTERNOON/EARLY
EVENING.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30 KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
STEADY SNOWFALL CONTINUES THROUGH THE AFTERNOON AND EVENING. THE
SNOW HAS BEEN WET TO THIS POINT...BUT FROM NORTH TO SOUTH IT WILL
SHIFT TO A DRIER SNOW AS THE AFTERNOON AND EVENING GO ON.
VISIBILITIES HAVE BEEN LARGELY STEADY AROUND 1/2 MILE...AND WHILE
FLUCTUATIONS IN THIS WILL OCCUR FROM TIME TO TIME...EXPECT 1/2 TO
3/4 VSBYS TO GENERALLY BE THE RULE. AS THE WINDS RAMP UP LATER THIS
AFTERNOON AND EVENING...FEEL THAT THERE WILL BE OCCASIONAL 1/4 MILE
VISIBILITIES AS THE SNOW GETS A BIT MORE BLOWABLE...BUT STILL NOT
CONFIDENT IN THIS CONDITION PREVAILING. WILL HAVE TO MONITOR AS THE
WINDS RAMP UP. IF THIS WERE TO OCCUR...IT WOULD BE THE LATE
AFTERNOON AND EARLY EVENING PERIOD WHEN THE SURFACE LOW MOVES A BIT
FARTHER NORTH AND EAST. THINK THAT THE 22Z-02Z TIME FRAME WOULD BE
THE BEST BET FOR THIS. WINDS HOLD IN THE 050 DIRECTION THEN BACK
THROUGH THE EVENING TO 020 BY MID EVENING...THEN NNW OVERNIGHT.
SHOULD SEE SOME SLIGHTY IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL
FROM 4Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND. EXPECT LIGHT LAKE EFFECT SNOW SHOWERS OVERNIGHT.
MOST TERMINALS EXCEPT MDW AND GYY SHOULD BE DRY BY DAYBREAK WITH A
WEAKENING WESTERLY WIND.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1036 AM CST SUN FEB 1 2015
.UPDATE...1031 AM CST
WE HAVE INCREASED SNOWFALL AMOUNTS SOME THIS AFTERNOON...ESPECIALLY
ACROSS NORTHERN ILLINOIS AND FAR NORTHWESTERN INDIANA. A VERY
IMPRESSIVE SYSTEM CONTINUES TO DEVELOP ACROSS THE CENTRAL CONUS THIS
MORNING IN RESPONSE TO A STRONG PV ANOMALY OVER THE CENTRAL PLAINS.
AS THIS STORM CONTINUES TO INTENSIFY THIS AFTERNOON...MODEL GUIDANCE
SUGGESTS THAT A BAND OF STRONG FRONTOGENESIS WILL DEVELOP IN AN
EMERGING DEFORMATION ZONE ASSOCIATED WITH THE 700 MB LOW...RIGHT
ACROSS NORTHERN ILLINOIS. THIS ALSO LOOKS TO OCCUR DURING THE
PERIOD OF BEST STRONG MID/UPPER LEVEL Q-VECTOR DIVERGENCE
ASSOCIATED WITH THE MID/UPPER LEVEL SYSTEM. ALL IN ALL THIS POINTS
TO STRONG DYANAMICS SUPPORTIVE OF PERIODS OF HEAVY SNOW THROUGH
THE DAY TODAY...AND LINGERING THIS EVENING. IT APPEARS THE
HEAVIEST AMOUNTS WILL EXCEED A FOOT IN MANY AREAS...WITH A FOOT
AND A HALF NOT OUT OF THE QUESTION FOR NORTHERN ILLINOIS.
THE OTHER CONCERN IS BLIZZARD CONDITIONS...WE ARE UPGRADING THE REST
OF NORTH CENTRAL ILLINOIS TO A BLIZZARD WARNING. NORTHEASTERLY
WINDS WILL ONLY INCREASE THROUGH THE AFTERNOON...WITH GUSTS
POTENTIAL UP AROUND 40 KT AT TIMES GIVEN THE STRONG GRADIENT SETTING
UP ON THE BACK SIDE OF THIS SYSTEM. THIS HAS ME SERIOUSLY CONCERNED
THAT AS THE SNOW CONTINUES TO BECOME MORE POWDERY THROUGH THE
DAY...THAT WHITE OUT CONDITIONS WILL BE OBSERVED ACROSS NORTHERN
ILLINOIS. THE OTHER CONCERN IS FOR DOWNED TREE BRANCHES AND POWER
LINES. THE SNOW THAT HAS FALLEN THUS FAR ACROSS THE AREA HAS BEEN A
STICKY WET SNOW AND HAS PRODUCED SIGNIFICANT ACCUMULATIONS ON TREES
AND POWER LINES. THE INCREASING WINDS COULD BRING DOWN POWER
LINES...LEADING TO SOME ISOLATED POWER OUTAGES.
NEW UPDATES SHOULD BE OUT SHORTLY.
KJB
&&
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SNOW THROUGH TOMORROW MORNING. PREVAILING VIS UNDER 1SM THROUGH
THIS EVENING. VIS ARND 1/2SM THROUGH EARLY EVENING.
* NELY WINDS INCREASING THROUGH THE MORNING...GUSTING TO 30-35KT
THIS AFTERNOON. OCNL HIGHER GUSTS POSSIBLE.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KREIN/KMD
//DISCUSSION...UPDATED 16Z...
SOLID SWATH OF SNOW ACROSS THE TERMINALS THIS MORNING WITH VSBYS
GENERALLY HOLDING AROUND 1/2 MILE. CIGS ARE GENERALLY IN THE
500-900 FT RANGE NORTH OF KARR...300-500 SOUTH WHERE HIGHER
DEWPOINTS EXIST. A BRIEF LET-UP IN SNOW IS POSSIBLE EARLY
AFTERNOON BUT EXPECT THIS WOULD NOT LAST LONG. CONFIDENCE IS NOT
HIGH ENOUGH TO GO PREVAILING 1/4 MILE JUST YET WITH SOME
UNCERTAINTY AS TO SNOWFALL RATES AND HOW FLUFFY THE SNOW WILL BE THIS
AFTERNOON AND ALSO GIVEN THE WET SNOW THAT HAS FALLEN TO THIS POINT...BUT
WINDS WILL INCREASE SIGNIFICANTLY AND WILL HOLD THAT WAY THROUGH
THE EVENING. TRIED TO PEG THE BEST TIME FRAME FOR THIS...BUT THE
TEMPO 1/4 COULD BECOME MORE PREVAILNG...AND MAY LAST LONGER THIS
EVENING IF THE WINDS REACH THE LEVELS THAT THE GFS/GFS LAMP IS
PROGGING.
SHOULD SEE SOME IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL FROM
3Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND.
PREVIOUS DISCUSSION FROM 12Z...
LONG DURATION SNOW EVENT UNDERWAY AS LOW PRESSURE OVER MISSOURI
MOVES EAST THROUGH SOUTHERN ILLINOIS AND INDIANA BY THIS EVENING
AS IT SLOWLY STRENGTHENS. MOISTURE STREAMING NORTH FROM THE GULF
OF MEXICO WILL ALLOW THIS SYSTEM TO PRODUCE MODERATE SNOW THROUGH
THIS EVENING...BEFORE SLOWLY TAPERING OFF LATE TONIGHT INTO EARLY
MONDAY MORNING. VISIBILITIES WILL LIKELY FLUCTUATE WITH HEAVIER
BANDS OF SNOW...BUT PREVAILING VIS LIKELY TO BE AROUND 1/2SM FOR
MUCH OF THE EVENT. AS WINDS STRENGTHEN WITH GUSTS OF 30-35KT...OR
POSSIBLY HIGHER...THIS AFTERNOON AND EARLY EVENING...VIS COULD
DROP TO 1/4SM OR LOWER IN PERIODS OF HEAVIER SNOWFALL AND STRONGER
WIND GUSTS. WINDS WILL TURN MORE NORTHERLY LATE THIS EVENING AND
THEN BEGIN TO DIMINISH EARLY MONDAY MORNING AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KREIN/KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1031 AM CST SUN FEB 1 2015
.UPDATE...
1031 AM CST
WE HAVE INCREASED SNOWFALL AMOUNTS SOME THIS AFTERNOON...ESPECIALLY
ACROSS NORTHERN ILLINOIS AND FAR NORTHWESTERN INDIANA. A VERY
IMPRESSIVE SYSTEM CONTINUES TO DEVELOP ACROSS THE CENTRAL CONUS THIS
MORNING IN RESPONSE TO A STRONG PV ANOMALY OVER THE CENTRAL PLAINS.
AS THIS STORM CONTINUES TO INTENSIFY THIS AFTERNOON...MODEL GUIDANCE
SUGGESTS THAT THE DEFORMATION ZONE...FEATURING A BAND OF STRONG
FRONTOGENESIS COINCIDENT WITH STRONG MID/UPPER LEVEL Q-VECTOR
DIVERGENCE. ALL IN ALL THIS POINTS TO PERIODS OF HEAVY SNOW THROUGH
THE DAY TODAY...AND LINGERING THIS EVENING. IT APPEARS THE HEAVIEST
AMOUNTS WILL EXCEED A FOOT IN MANY AREAS...WITH A FOOT AND A HALF
NOT OUT OF THE QUESTION FOR NORTHERN ILLINOIS.
THE OTHER CONCERN IS BLIZZARD CONDITIONS...WE ARE UPGRADING THE REST
OF NORTH CENTRAL ILLINOIS TO A BLIZZARD WARNING. NORTHEASTERLY
WINDS WILL ONLY INCREASE THROUGH THE AFTERNOON...WITH GUSTS
POTENTIAL UP AROUND 40 KT AT TIMES GIVEN THE STRONG GRADIENT SETTING
UP ON THE BACK SIDE OF THIS SYSTEM. THIS HAS ME SERIOUSLY CONCERNED
THAT AS THE SNOW CONTINUES TO BECOME MORE POWDERY THROUGH THE
DAY...THAT WHITE OUT CONDITIONS WILL BE OBSERVED ACROSS NORTHERN
ILLINOIS. THE OTHER CONCERN IS FOR DOWNED TREE BRANCHES AND POWER
LINES. THE SNOW THAT HAS FALLEN THUS FAR ACROSS THE AREA HAS BEEN A
STICKY WET SNOW AND HAS PRODUCED SIGNIFICANT ACCUMULATIONS ON TREES
AND POWER LINES. THE INCREASING WINDS COULD BRING DOWN POWER
LINES...LEADING TO SOME ISOLATED POWER OUTAGES.
NEW UPDATES SHOULD BE OUT SHORTLY.
KJB
&&
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SNOW THROUGH TOMORROW MORNING. PREVAILING VIS UNDER 1SM THROUGH
THIS EVENING. VIS ARND 1/2SM THROUGH EARLY EVENING.
* NELY WINDS INCREASING THROUGH THE MORNING...GUSTING TO 30-35KT
THIS AFTERNOON. OCNL HIGHER GUSTS POSSIBLE.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KREIN/KMD
//DISCUSSION...UPDATED 16Z...
SOLID SWATH OF SNOW ACROSS THE TERMINALS THIS MORNING WITH VSBYS
GENERALLY HOLDING AROUND 1/2 MILE. CIGS ARE GENERALLY IN THE
500-900 FT RANGE NORTH OF KARR...300-500 SOUTH WHERE HIGHER
DEWPOINTS EXIST. A BRIEF LET-UP IN SNOW IS POSSIBLE EARLY
AFTERNOON BUT EXPECT THIS WOULD NOT LAST LONG. CONFIDENCE IS NOT
HIGH ENOUGH TO GO PREVAILING 1/4 MILE JUST YET WITH SOME
UNCERTAINTY AS TO SNOWFALL RATES AND HOW FLUFFY THE SNOW WILL BE THIS
AFTERNOON AND ALSO GIVEN THE WET SNOW THAT HAS FALLEN TO THIS POINT...BUT
WINDS WILL INCREASE SIGNIFICANTLY AND WILL HOLD THAT WAY THROUGH
THE EVENING. TRIED TO PEG THE BEST TIME FRAME FOR THIS...BUT THE
TEMPO 1/4 COULD BECOME MORE PREVAILNG...AND MAY LAST LONGER THIS
EVENING IF THE WINDS REACH THE LEVELS THAT THE GFS/GFS LAMP IS
PROGGING.
SHOULD SEE SOME IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL FROM
3Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND.
PREVIOUS DISCUSSION FROM 12Z...
LONG DURATION SNOW EVENT UNDERWAY AS LOW PRESSURE OVER MISSOURI
MOVES EAST THROUGH SOUTHERN ILLINOIS AND INDIANA BY THIS EVENING
AS IT SLOWLY STRENGTHENS. MOISTURE STREAMING NORTH FROM THE GULF
OF MEXICO WILL ALLOW THIS SYSTEM TO PRODUCE MODERATE SNOW THROUGH
THIS EVENING...BEFORE SLOWLY TAPERING OFF LATE TONIGHT INTO EARLY
MONDAY MORNING. VISIBILITIES WILL LIKELY FLUCTUATE WITH HEAVIER
BANDS OF SNOW...BUT PREVAILING VIS LIKELY TO BE AROUND 1/2SM FOR
MUCH OF THE EVENT. AS WINDS STRENGTHEN WITH GUSTS OF 30-35KT...OR
POSSIBLY HIGHER...THIS AFTERNOON AND EARLY EVENING...VIS COULD
DROP TO 1/4SM OR LOWER IN PERIODS OF HEAVIER SNOWFALL AND STRONGER
WIND GUSTS. WINDS WILL TURN MORE NORTHERLY LATE THIS EVENING AND
THEN BEGIN TO DIMINISH EARLY MONDAY MORNING AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KREIN/KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1025 AM CST SUN FEB 1 2015
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SNOW THROUGH TOMORROW MORNING. PREVAILING VIS UNDER 1SM THROUGH
THIS EVENING. VIS ARND 1/2SM THROUGH EARLY EVENING.
* NELY WINDS INCREASING THROUGH THE MORNING...GUSTING TO 30-35KT
THIS AFTERNOON. OCNL HIGHER GUSTS POSSIBLE.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KREIN/KMD
//DISCUSSION...UPDATED 16Z...
SOLID SWATH OF SNOW ACROSS THE TERMINALS THIS MORNING WITH VSBYS
GENERALLY HOLDING AROUND 1/2 MILE. CIGS ARE GENERALLY IN THE
500-900 FT RANGE NORTH OF KARR...300-500 SOUTH WHERE HIGHER
DEWPOINTS EXIST. A BRIEF LET-UP IN SNOW IS POSSIBLE EARLY
AFTERNOON BUT EXPECT THIS WOULD NOT LAST LONG. CONFIDENCE IS NOT
HIGH ENOUGH TO GO PREVAILING 1/4 MILE JUST YET WITH SOME
UNCERTAINTY AS TO SNOWFALL RATES AND HOW FLUFFY THE SNOW WILL BE THIS
AFTERNOON AND ALSO GIVEN THE WET SNOW THAT HAS FALLEN TO THIS POINT...BUT
WINDS WILL INCREASE SIGNIFICANTLY AND WILL HOLD THAT WAY THROUGH
THE EVENING. TRIED TO PEG THE BEST TIME FRAME FOR THIS...BUT THE
TEMPO 1/4 COULD BECOME MORE PREVAILNG...AND MAY LAST LONGER THIS
EVENING IF THE WINDS REACH THE LEVELS THAT THE GFS/GFS LAMP IS
PROGGING.
SHOULD SEE SOME IMPROVEMENT IN VSBY AND DECREASE IN SNOWFALL FROM
3Z-6Z...AND AFTER 6Z SNOWFALL SHOULD DECREASE SIGNIFICANTLY
THOUGH NOT END...AND WINDS SHOULD START A MORE SIGNIFICANT
DOWNWARD TREND.
PREVIOUS DISCUSSION FROM 12Z...
LONG DURATION SNOW EVENT UNDERWAY AS LOW PRESSURE OVER MISSOURI
MOVES EAST THROUGH SOUTHERN ILLINOIS AND INDIANA BY THIS EVENING
AS IT SLOWLY STRENGTHENS. MOISTURE STREAMING NORTH FROM THE GULF
OF MEXICO WILL ALLOW THIS SYSTEM TO PRODUCE MODERATE SNOW THROUGH
THIS EVENING...BEFORE SLOWLY TAPERING OFF LATE TONIGHT INTO EARLY
MONDAY MORNING. VISIBILITIES WILL LIKELY FLUCTUATE WITH HEAVIER
BANDS OF SNOW...BUT PREVAILING VIS LIKELY TO BE AROUND 1/2SM FOR
MUCH OF THE EVENT. AS WINDS STRENGTHEN WITH GUSTS OF 30-35KT...OR
POSSIBLY HIGHER...THIS AFTERNOON AND EARLY EVENING...VIS COULD
DROP TO 1/4SM OR LOWER IN PERIODS OF HEAVIER SNOWFALL AND STRONGER
WIND GUSTS. WINDS WILL TURN MORE NORTHERLY LATE THIS EVENING AND
THEN BEGIN TO DIMINISH EARLY MONDAY MORNING AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KREIN/KMD
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM MONDAY.
BLIZZARD WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001 UNTIL MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
558 AM CST SUN FEB 1 2015
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* SNOW THROUGH TOMORROW MORNING. PREVAILING VIS UNDER 1SM THROUGH
THIS EVENING. VIS ARND 1/2SM THROUGH EARLY EVENING.
* NELY WINDS INCREASING THROUGH THE MORNING...GUSTING TO 30-35KT
THIS AFTERNOON. OCNL HIGHER GUSTS POSSIBLE.
* BLOWING AND DRIFTING SNOW LIKELY THIS AFTERNOON AND TONIGHT.
* PERIODS OF VIS 1/4SM OR LESS THIS AFTERNOON WHEN GUSTS INCREASE
TO 30KT AND HIGHER.
* IFR-LIFR CIGS THROUGH LATE EVENING.
KREIN
//DISCUSSION...UPDATED 12Z...
LONG DURATION SNOW EVENT UNDERWAY AS LOW PRESSURE OVER MISSOURI
MOVES EAST THROUGH SOUTHERN ILLINOIS AND INDIANA BY THIS EVENING
AS IT SLOWLY STRENGTHENS. MOISTURE STREAMING NORTH FROM THE GULF
OF MEXICO WILL ALLOW THIS SYSTEM TO PRODUCE MODERATE SNOW THROUGH
THIS EVENING...BEFORE SLOWLY TAPERING OFF LATE TONIGHT INTO EARLY
MONDAY MORNING. VISIBILITIES WILL LIKELY FLUCTUATE WITH HEAVIER
BANDS OF SNOW...BUT PREVAILING VIS LIKELY TO BE AROUND 1/2SM FOR
MUCH OF THE EVENT. AS WINDS STRENGTHEN WITH GUSTS OF 30-35KT...OR
POSSIBLY HIGHER...THIS AFTERNOON AND EARLY EVENING...VIS COULD
DROP TO 1/4SM OR LOWER IN PERIODS OF HEAVIER SNOWFALL AND STRONGER
WIND GUSTS. WINDS WILL TURN MORE NORTHERLY LATE THIS EVENING AND
THEN BEGIN TO DIMINISH EARLY MONDAY MORNING AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM TO HIGH CONFIDENCE IN WX/VIS TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM CONFIDENCE IN TIMING OF IMPROVING CIG/VIS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...VFR/WX NIL EARLY. CHANCE SNOW WITH MVFR CIGS/VIS
LATE.
TUESDAY...SLIGHT CHANCE SNOW EARLY WITH MVFR CIGS/VIS. VFR/WX NIL
AFTERNOON. SNOW LIKELY WITH IFR CIG/VIS OVERNIGHT.
WEDNESDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS EARLY. VFR/WX NIL
OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
SATURDAY...SLIGHT CHANCE SNOW WITH MVFR CIG/VIS POSSIBLE.
KREIN
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ011-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022 UNTIL 2 PM SUNDAY.
LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014...2 PM SUNDAY TO 10 AM
MONDAY.
BLIZZARD WARNING...ILZ005-ILZ006-ILZ011-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022...2 PM SUNDAY TO MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ019-ILZ021-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001...2 PM SUNDAY TO MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ001 UNTIL 2 PM SUNDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...9 AM SUNDAY TO 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM SUNDAY TO
3 AM MONDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
347 AM CST SUN FEB 1 2015
.SHORT TERM...
347 AM CST
THROUGH MONDAY...
HAVE BEEN SWAMPED THIS MORNING AND AM RUNNING BEHIND...SO GOING TO
KEEP DISCUSSION BRIEF THIS MORNING AND JUST HIT THE IMPORTANT
CHANGES. THE BIGGEST CHANGES TO GOING FORECAST IS THE UPGRADE TO
A BLIZZARD WARNING FOR PORTIONS OF NE IL/CHICAGO METRO AND TO
LOWER SNOW AMOUNTS AND ADD MIXED PRECIP BACK INTO GRIDS FAR SE
CWA.
GUIDANCE HAS CONTINUED TO TREND NORTH AND STRONGER WITH THE TRACK OF
THIS SYSTEM AND COMPARING GUIDANCE WITH SFC OBS AND BEST SFC
PRESSURE FALLS IT WOULD SEEM TO SUPPORT THE FARTHER NORTH TRACK THAT
THE RAP IN PARTICULAR HAS LATCHED ONTO. THE SOMEWHAT DEEPER LOW
ALONG WITH THE VERY STRONG ARCTIC HIGH SPREADING SOUTHEAST WILL
RESULT IN VERY STRONG WINDS DEVELOPING THIS AFTERNOON. INCREASING
LOW LEVEL COLD AIR ADVECTION AND SFC HEIGHT RISES FAVOR PRETTY GOOD
MIXING IN THE BOUNDARY LAYER...WHICH IS WHAT ALL MODEL FORECAST
SOUNDINGS ARE ADVERTISING. TAKING EVEN THE BEST CASE SCENARIO AND
ONE OF THE WEAKEST MODELS BUFKIT MOMENTUM TRANSFER VALUES SUPPORT
4-7 HOURS OF WIND GUSTS BETWEEN 35-40 MPH LATER THIS AFTERNOON AND
EVENING...WITH MORE AGGRESSIVE GFS/RAP SUPPORTING EVEN STRONGER
WINDS OVER A LONGER DURATION. SNOW HAS BEEN WET THUS FAR BUT WITH
TIME SHOULD SEE THE TRANSITION TOWARD DRIER/MORE BLOWABLE SNOW THIS
AFTERNOON FROM NORTH TO SOUTH AS THE COLUMN COOLS AND THE SNOW
LIQUID CONTENT DECREASES. BIGGEST UNCERTAINTY REVOLVES AROUND
REGARDING UPGRADE TO BLIZZARD WARNING WAS THE SNOW LIQUID CONTENT
AND PROBABILITY AND CONFIDENCE IS CERTAINLY HIGHER THE FARTHER NORTH
FROM I-80 THAT YOU GET...BUT EVEN AS FAR SOUTH AS I-80 FELT FAIRLY
CONFIDENT THAT WHITE OUT CONDITIONS COULD DEVELOP LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING. FARTHER WEST ACROSS NORTH
CENTRAL ILLINOIS FEEL THAT A BLIZZARD WARNING COULD EASILY BE
JUSTIFIED...BUT IN COORDINATION WITH MKX/DVN HAVE OPTED TO HOLD OFF
FOR NOW AS SNOW INTENSITY COULD BE DECREASING AS WINDS PICK UP.
QUITE POSSIBLE DAY SHIFT MAY NEED TO RE-ACCESS THIS AND AN UPGRADE
TO BLIZZARD WARNING FOR RFD AND POINTS WEST COULD OCCUR ON THE DAY
SHIFT.
OTHER BIG CHANGE TO FORECAST WAS TO ADD SLEET AND THEN DRIZZLE TO
THE FAR SOUTHEAST CWA. SFC TEMPS HAVE BEEN A BIT WARMER AND THE
FARTHER NORTH TRACK OF THE SFC LOW SHOULD KEEP LOW LEVEL WAA GOING
INTO EARLY AFTERNOON WITH AT LEAST THE THREAT OF MIXED
PRECIP...POSSIBLY TRANSITIONING OVER TO JUST DRIZZLE/SNIZZLE AS MID
LEVEL DRY SLOT OVERSPREADS THAT AREA REMOVING ICE NUCLEI FROM THE
CLOUDS LATE THIS AFTERNOON INTO THIS EVENING. THE WETTER SNOW SOUTH
OF I-80 SHOULD RESULT IN LESS SEVERE AND LESS IMPACTFUL
BLOWING/DRIFTING SNOW. GIVEN THE MARGINAL TEMPS AND POTENTIAL MIX
PRECIP HAVE CUT BACK ON ACCUMS IN THE FAR SOUTHEAST COUNTIES OF THE
CWA.
ACCUMULATING LAKE EFFECT POTENTIAL ACTUALLY LOOKS SOMEWHAT LESS
IMPRESSIVE THAN IT DID LAST NIGHT...AND IT WAS ALREADY LOOKING
MARGINAL. SOME SYSTEM SNOWS SHOULD LINGER INTO THIS EVENING BUT LAKE
CONTRIBUTIONS LOOK MINOR WITH LOW INVERSION HEIGHTS AND DECREASING
BOUNDARY LAYER RH AS THE THERMODYNAMICS IMPROVE EVER SO SLIGHTLY.
ANY LAKE ENHANCEMENT TO SNOW TOTALS SHOULD END UP BEING TRIVIAL.
FINALLY...GOING SNOWFALL TOTALS LOOK RIGHT ON TARGET AND MADE VERY
FEW CHANGES OTHER THAN IN SE AS NOTED ABOVE. A RESPECTABLY LARGE
SWATH OF A FOOT OR MORE OF SNOW STILL LOOKS LIKELY AND PROBABLY
CENTERED RELATIVELY CLOSE TO THE I-80 TO I-88/290 CORRIDORS.
ACTUALLY THINKING THAT MAX SNOWFALL TOTALS IN THE CWA COULD END UP
BEING ON THE HIGH END OF THE 10-14 INCH RANGE WITH LOCALIZED TOTALS
POTENTIALLY PUSHING A FOOT AND A HALF IF THE DEFO BAND IS INDEED AS
IMPRESSIVE AS SOME OF THE GUIDANCE WOULD SUGGEST. WHILE SNOWFALL
TOTALS WILL BE VERY IMPRESSIVE OVER MOST OF THE CWA...IT IS
IMPORTANT TO REMEMBER THE BLIZZARD WARNING IS ISSUED NOT FOR
SNOWFALL AMOUNTS BUT RATHER FOR VISIBILITY AND WINDS. THE CRITERIA
FOR BLIZZARD WARNING IS 3+ HOURS OF LESS THAN 1/4SM VSBY IN FALLING
AND/OR BLOWING SNOW ALONG WITH SUSTAINED WINDS OR FREQUENT GUSTS
OVER 35 MPH.
IZZI
&&
.LONG TERM...
MONDAY NIGHT THROUGH SATURDAY...
134 AM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
NIGHT INTO TUESDAY...THEN A BETTER CHANCE FOR ACCUMULATING LIGHT
SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING.
A RIDGE OF HIGH PRESSURE WILL BE MOVING SOUTHEAST OF THE AREA
MONDAY EVENING AS A WEAK WAVE MOVES ACROSS THE REGION MONDAY NIGHT.
FAIRLY LIGHT QPF FROM ALL THE MODELS WITH THIS WAVE BUT PLENTY COLD
ENOUGH FOR THE LOW QPF AMOUNTS TO POTENTIALLY FLUFF UP TO A HALF
INCH MONDAY NIGHT. WHILE TEMPS BY THIS TIME WILL LIKELY BE IN THE
SINGLE DIGITS OR LOW TEENS...CLOUD COVER AND WEAK WARM AIR ADVECTION
MAY ALLOW TEMPS TO HOLD STEADY OR RISE A FEW DEGREES OVERNIGHT.
NEXT WAVE QUICKLY SHIFTS SOUTHEAST ACROSS THE AREA BY TUESDAY
EVENING WITH QPF AMOUNTS BETWEEN ONE AND TWO TENTHS. THIS HAS BEEN
A FAIRLY CONSISTENT FEATURE ON THE MODELS AND IF THIS MATERIALIZES
AS ADVERTISED...A FEW INCHES OF SNOW WILL BE POSSIBLE. TIMING AND
LOCATION ALSO ARE A BIT UNCERTAIN...EARLIER COULD IMPACT THE TUESDAY
EVENING RUSH...LATER COULD IMPACT THE WEDNESDAY MORNING RUSH. BUT
GIVEN THE POTENTIAL FOR SOME ACCUMULATION...OPTED TO BUMP POPS UP TO
LIKELY FOR TUESDAY NIGHT.
HIGH PRESSURE THEN SETTLES SOUTH ACROSS THE MIDWEST AND LAKES REGION
WEDNESDAY INTO THURSDAY AND WITH IT...SOME VERY COLD AIR. WITH A
DEEP SNOWPACK BY THAT TIME AND DIMINISHING WINDS WEDNESDAY NIGHT
INTO THURSDAY...EXPECT MANY LOCATIONS TO DROP BELOW ZERO FOR LOWS
THURSDAY MORNING. THE AIRMASS MODIFIES/WARMS SOME THURSDAY BUT
STILL EXPECTING LOWS IN THE LOWER SINGLE DIGITS THURSDAY EVENING...
POSSIBLY BELOW ZERO BUT WARM AIR ADVECTION BY MORNING WITH
INCREASING SOUTHERLY WINDS MAY PUT THE BRAKES ON HOW LOW TEMPS FALL
THURSDAY NIGHT. STRONG SOUTHERLY WINDS CONTINUE INTO SATURDAY WITH
WARMING TEMPS...THAT WILL LIKELY BE MUTED SOME BY THE SNOWPACK. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* SNOW THRU THE PERIOD. VISIBILITIES GENERALLY AROUND 3/4SM...WITH
OCNL PERIODS OF VIS AS LOW AS 1/4SM POSSIBLE ESPECIALLY THIS
AFTERNOON.
* STRONG NORTHEAST WINDS SUNDAY...GUSTING UP TO 35 KT.
* BLOWING SNOW SUNDAY AND SUNDAY NIGHT.
* IFR/LIFR CIGS THRU THE PERIOD.
KREIN
//DISCUSSION...UPDATED 06Z...
LONG DURATION SNOW EVENT UNDERWAY AS LOW PRESSURE OVER KANSAS
MOVES EAST TO SOUTHERN INDIANA BY SUNDAY EVENING AS IT SLOWLY
STRENGTHENS. MOISTURE STREAMING NORTH FROM THE GULF WILL ALLOW
THIS SYSTEM TO PRODUCE MODERATE SNOW THROUGH SUNDAY EVENING...
BEFORE SLOWLY TAPERING OFF LATE SUNDAY EVENING AND EARLY MONDAY
MORNING. VISIBILITIES WILL LIKELY FLUCTUATE FROM TIME TO TIME
BUT PREVAILING VIS LIKELY TO BE AROUND 1/2SM FOR MUCH OF THE
EVENT.
AS THE GRADIENT STRENGTHENS SUNDAY MORNING...NORTHEAST WINDS
WILL INCREASE UP TO 20KTS WITH GUSTS 30-35KTS FOR MUCH OF THE
AFTERNOON AND EVENING. THESE STRONG WINDS WILL PRODUCE BLOWING
AND DRIFTING SNOW THAT MAY REDUCE VISIBILITIES UNDER 1/2SM AT
TIMES. THE WINDS WILL TURN MORE NORTHERLY SUNDAY EVENING AND
THEN BEGIN TO DIMINISH EARLY MONDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH FOR SNOW/VIS THRU THE PERIOD.
* HIGH FOR WINDS/GUSTS THRU THE PERIOD.
* HIGH FOR BLOWING SNOW SUNDAY/SUNDAY NIGHT.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE LINGERING SNOW SHOWERS IN THE MORNING. CHANCE OF
SNOW AGAIN AFTER MIDNIGHT. MVFR CIGS/VIS LIKELY. IFR POSSIBLE.
TUESDAY...CHANCE SNOW. PERIODS OF MVFR CIGS/VIS LIKELY...IFR VSBY
POSSIBLE.
WEDNESDAY...SLIGHT CHANCE SNOW THROUGH EARLY EVENING. PERIODS OF
MVFR CIGS/VIS POSSIBLE. VFR/WX NIL OVERNIGHT.
THURSDAY...VFR/WX NIL.
FRIDAY...VFR/WX NIL.
MDB
&&
.MARINE...
315 AM CST
THE SFC LOW OVER THE PLAINS LOOKS TO BE DEEPENING A LITTLE FASTER
AND LOWER WHILE THE HIGH PRESSURE RIDGING OVER THE UPPER GREAT
LAKES IS TRENDING A LITTLE STRONGER. THIS COMBINATION WITH STRONG
COLD ADVECTION SETTING UP OVER THE LAKE TODAY...HAVE EXPANDED THE
GALE WARNING OVER THE ENTIRE OPEN WATERS OF LAKE MICHIGAN AS WELL
AS EXTENDING IN TIME...STARTING A LITTLE EARLIER...AT 15Z THIS
MORNING AND GOING A LITTLE LATER...TO 09Z TONIGHT. ALSO...HAVE
INCREASED GALES TO 40KT OVER THE SOUTHERN PORTIONS OF THE LAKE
WHERE THE PRESSURE GRADIENT AND PRESSURE FALLS ARE STRONGEST. AS
THE WINDS PICK UP TO GALE FORCE AND MUCH COLDER AIR FILTERS OVER
THE LAKE LATER TODAY...HEAVY FREEZING SPRAY WILL BE LIKELY...SO
HAVE ALSO ISSUED A HEAVY FREEZING SPRAY WARNING FROM 15Z THIS
MORNING TO 09Z TONIGHT. THE COLDER AIR WILL SPREAD OVER THE
NORTHERN PORTIONS OF THE LAKE EARLIER THAN THE SOUTHERN
PORTIONS...SO IT IS POSSIBLE THAT THE HEAVY FREEZING SPRAY
POTENTIAL MAY NOT REACH THE SOUTHERN PORTIONS OF THE LAKE UNTIL
THIS AFTERNOON...BUT WENT WITH ONE SEGMENT TO THE WARNING TO
COINCIDE WITH THE GALE WARNING TIMING. THE LOW SHOULD PUSH EAST
INTO THE MID ATLANTIC REGION BE MONDAY AFTERNOON...WHILE HIGH
PRESSURE SPREADS ACROSS THE MISSISSIPPI RIVER INTO THE WESTERN
GREAT LAKES REGION. THIS WILL LEAD TO SUBSIDING WINDS AND
WAVES...ESPECIALLY AS WEAK HIGH PRESSURE PRESSURE CROSSES THE LAKE
MONDAY NIGHT AND TUESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006-ILZ011-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022 UNTIL 2 PM SUNDAY.
BLIZZARD WARNING...ILZ005-ILZ006-ILZ011-ILZ012-ILZ013-ILZ014-
ILZ020-ILZ022...2 PM SUNDAY TO MIDNIGHT MONDAY.
WINTER STORM WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ019-ILZ021-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL MIDNIGHT MONDAY.
IN...BLIZZARD WARNING...INZ001...2 PM SUNDAY TO MIDNIGHT MONDAY.
WINTER STORM WARNING...INZ001 UNTIL 2 PM SUNDAY.
WINTER STORM WARNING...INZ002-INZ010-INZ011-INZ019 UNTIL
MIDNIGHT MONDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...9 AM SUNDAY TO 3 AM MONDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM SUNDAY TO
3 AM MONDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM SUNDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
359 PM CST SUN FEB 1 2015
.DISCUSSION...
THE SCT CONVECTION HAS RAPIDLY MOVED E ACROSS LOWER E TX/NCNTRL LA
THIS AFTERNOON ALONG THE COLD FRONT...WHICH EXTENDS FROM THE MS RIVER
ALONG THE AR/MS BORDER SW TO LLQ...TO ELD...TO JUST N OF A IER...TO S
OF A LFK LINE AS OF 21Z. THE HRRR CONTINUES TO HAVE THE BEST HANDLE ON
THE ONGOING CONVECTION...WHICH SHOULD COMPLETELY EXIT THE AREA
BY/SHORTLY AFTER 00Z. BEHIND THE FRONT...GUSTY NW WINDS CONTINUE TO
EXPAND SE...WITH GUSTS TO 25KTS COMMON ACROSS EXTREME NE TX/SE OK/SW
AR. THE SHORT TERM PROGS DO AGREE ON A 6MB PRESSURE DIFFERENCE FROM W
TO E ACROSS THE CWA THIS EVENING...AND GIVEN THIS...HAVE EXPANDED THE
LAKE WIND ADVISORY THROUGH 10Z MONDAY TO COVER THE REMAINDER OF THE
CWA EXCEPT THE LOWER SAM RAYBURN COUNTRY OF DEEP E TX AS WELL AS THE
SRN PARISHES OF NCNTRL LA...WHERE WINDS SHOULD BE A BIT MORE MARGINAL.
STRONG COLD ADVECTION BEHIND THE FRONT SHOULD RESULT IN FREEZING TEMPS
OVER ALL BUT THE SRN AND ERN SECTIONS OF THE REGION...DESPITE THE
POST-FRONTAL STRATOCU OVER CNTRL/ERN OK NOT CLEARING UNTIL LATE
TONIGHT ACROSS SE OK/SW AR/NCNTRL LA.
CANADIAN SFC RIDGING WILL BEGIN TO SETTLE S ACROSS THE SRN PLAINS
MONDAY...THUS WEAKENING THE GRADIENT BY DAYBREAK. HOWEVER...EVEN WITH
ABUNDANT SUNSHINE...TEMPS WILL STRUGGLE TO CLIMB MUCH INTO THE
40S...STILL SOME 10-15 DEGREES BELOW NORMAL. WINDS SHOULD MOSTLY
DECOUPLE BY MONDAY NIGHT AS THE SFC RIDGE MOVES OVER THE REGION...BUT
SHOULD START TO SEE AN INCREASE IN CIRRUS LATE AS THE CLOSED LOW OVER
SRN BAJA THIS AFTERNOON...BEGINS TO NUDGE E INTO NW OLD MX MONDAY
NIGHT AND INTO S TX BY WEDNESDAY MORNING. THE INCREASED CIRRUS MAY
HELP OFFSET THE MORE IDEAL RADIATIONAL COOLING THAT WOULD NORMALLY
TAKE PLACE...BUT STILL EXPECTING MUCH OF THE AREA TO SEE SEVERAL HOURS
OF SUBFREEZING TEMPS. THE PROGS HAVE REMAINED FAIRLY CONSISTENT WITH
THE TRACK OF THIS LOW THE LAST 24 HOURS...WITH THE ELEVATED MOISTURE
INCREASING BY TUESDAY AFTERNOON...WITH AREAS OF -RA DEVELOPING MAINLY
OVER E TX/N LA. THE PROGS HAVE BACKED OFF CONSIDERABLY ON QPF WITH
THIS SYSTEM AS IT BEGINS TO OPEN UP AND ACCELERATE E ACROSS S LA
WEDNESDAY...WITH THE BEST FORCING MAINLY FOCUSED ALONG THE EXTREME SE
TX/SRN LA COASTS. HAVE LOWERED POPS TO LOW CHANCE TUESDAY NIGHT AND
WEDNESDAY FOR AREAS ALONG/S OF I-20...BEFORE THE NEXT SHORTWAVE
CLIPPER ROUNDS THE GREAT LAKES REGION WEDNESDAY AFTERNOON. THIS NEXT
SHORTWAVE SHOULD ALLOW FOR ANOTHER COLD FRONT TO NUDGE S WEDNESDAY
NIGHT/THURSDAY MORNING...DRIVING TEMPS BACK DOWN TO SOME 10 DEGREES
BELOW NORMAL ONCE AGAIN. CAN/T RULE OUT ISOLATED AREAS OF -RA
DEVELOPING NEAR/BEHIND THE FROPA...BUT THE MOISTURE PROFILE WILL
REMAIN SHALLOW WHILE THE BEST FORCING WILL BE NE OF THE AREA.
SHOULD AGAIN BEGIN TO SEE A MODERATION OF TEMPS BY FRIDAY AND
ESPECIALLY NEXT WEEKEND...AS TEMPS RETURN BACK ABOVE NORMAL. DRY
CONDITIONS SHOULD PERSIST THROUGH NEXT WEEKEND AS WELL.
PRELIMS TO FOLLOW BELOW...
15
&&
.PREV DISCUSSION... /ISSUED 1229 PM CST SUN FEB 1 2015/
AVIATION...
LOW CIGS THIS MORNING HAVE LIFTED TO MOSTLY MVFR LVLS ACROSS THE
AREA. A STG COLD FRONT JUST REACHING THE KTYR AND KTXK TERMINALS.
WSHFT ALONG FRONT TO INCREASE NW 15 KTS...WITH GUSTS OVER 25 KTS
INTO NE TX/SE OK. NARROW BAND OF HEAVY SHOWERS...CURRENTLY NEAR
KSHV AND KELD...JUST AHEAD OF FRONT. ISOLD TSTMS POSSIBLE...MAINLY
SOUTH OF I-20 AS PREFRONTAL TEMPS WARM INTO UPPER 60S TO LOWER 70S.
PREFRONTAL WINDS S-SW 10 TO 15 KTS. SKIES BECMG VFR SKC FROM THE
WEST BEGINNING AROUND 02/00Z. GUSTY NW WINDS TO CONTINUE UNTIL
AROUND 02/06Z...THEN BECMG NORTHERLY AT 5 TO 10 KTS THRU REMAINDER
OF FCST PERIOD. /VII/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 30 46 26 53 39 / 5 0 0 0 20
MLU 34 44 25 52 35 / 20 0 0 0 20
DEQ 24 42 22 52 32 / 0 0 0 0 0
TXK 28 43 25 52 37 / 5 0 0 0 10
ELD 29 43 23 52 34 / 5 0 0 0 10
TYR 27 43 30 53 40 / 5 0 0 0 20
GGG 28 44 27 53 39 / 5 0 0 0 20
LFK 33 49 29 53 41 / 10 0 0 10 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: ARZ050-051-059>061-070>073.
LA...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: LAZ001>006-010>014-021.
OK...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: OKZ077.
TX...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: TXZ096-097-108>112-124>126-136>138-149>153.
&&
$$
15
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1229 PM CST SUN FEB 1 2015
.AVIATION...
LOW CIGS THIS MORNING HAVE LIFTED TO MOSTLY MVFR LVLS ACROSS THE
AREA. A STG COLD FRONT JUST REACHING THE KTYR AND KTXK TERMINALS.
WSHFT ALONG FRONT TO INCREASE NW 15 KTS...WITH GUSTS OVER 25 KTS
INTO NE TX/SE OK. NARROW BAND OF HEAVY SHOWERS...CURRENTLY NEAR
KSHV AND KELD...JUST AHEAD OF FRONT. ISOLD TSTMS POSSIBLE...MAINLY
SOUTH OF I-20 AS PREFRONTAL TEMPS WARM INTO UPPER 60S TO LOWER 70S.
PREFRONTAL WINDS S-SW 10 TO 15 KTS. SKIES BECMG VFR SKC FROM THE
WEST BEGINNING AROUND 02/00Z. GUSTY NW WINDS TO CONTINUE UNTIL
AROUND 02/06Z...THEN BECMG NORTHERLY AT 5 TO 10 KTS THRU REMAINDER
OF FCST PERIOD./VII/.
&&
.PREV DISCUSSION... /ISSUED 1141 AM CST SUN FEB 1 2015/
DISCUSSION...
A 20-30NM WIDE BAND OF SHOWERS AND ISOLATED THUNDERSTORMS HAS
DEVELOPED ALONG A COLD FRONT...WHICH EXTENDS FROM NEAR LIT...TO
ADF...TO TXK...TO JXI/TYR...TO JUST E OF CRS AND TPL AS OF 17Z.
THIS CONVECTION HAS RESULTED IN 20-25KT WIND GUSTS ACROSS SW AR/NE
TX WITH ITS PASSAGE...ALTHOUGH WEAK CIN CONTRIBUTED BY THE LOW
LEVEL INVERSION NOTED ON THE 12Z KSHV RAOB CONTINUES TO HOLD
ACROSS SW AR/EXTREME NRN LA. FARTHER S...SOME BREAKS IN THE
STRATUS HAS BEEN NOTED...WITH LFK HAVING JUMPED INTO THE MID 70S.
SHOULD SEE SOME WEAK SFC BASED INSTABILITY DEVELOP THIS AFTERNOON
FROM LOWER TOLEDO BEND COUNTRY NE ACROSS NCNTRL LA AS SOME OF
THESE BREAKS MAY EXTEND NE OVER THESE AREAS...WITH CONTINUED
MOISTURE ADVECTION/BNDRY LYR HEATING CONTRIBUTING TO 500-800 J/KG
OF MLCAPE. FRONTAL CONVERGENCE REMAINS STRONG LATE THIS MORNING
WHERE THE CONVECTION IS ONGOING...WITH THE SHORT TERM PROGS
ACTUALLY MAINTAINING THE FRONTAL CONVERGENCE THROUGH THE AFTERNOON
WHERE A LITTLE BETTER INSTABILITY IS EXPECTED. HOWEVER...LAPSE
RATES ALOFT WILL BE QUITE MARGINAL...WITH THE BEST FORCING
EXPECTED TO BE ON THE NRN FRINGE OF THE WEAK INSTABILITY AXIS.
WHILE BRIEF WIND GUSTS TO 30-35KTS WILL BE POSSIBLE WITH THE
STRONGER CONVECTION...HAVE LOW CONFIDENCE IN SVR CONVECTION DEVELOPING
OVER THE AREA THIS AFTERNOON GIVEN THE VERY MARGINAL THERMODYNAMIC
ENVIRONMENT.
HOWEVER...THE FRONT IS MAKING A LITTLE FASTER PROGRESS SE THAN
EARLIER ANTICIPATED...WITH THE LATEST HRRR RUN HANDLING THE
FRONTAL PROGRESSION QUITE WELL. THE 12Z NAM IS ABOUT 3 HOURS
SLOWER...WITH THE GFS POSITION VERY SIMILAR IF NOT A TAD SLOWER
THAN THE HRRR. THUS...THE CONVECTION SHOULD MOVE OUT OF THE REGION
A LITTLE FASTER THAN EXPECTED LATER THIS AFTERNOON.
HOWEVER...THE MSAS ANALYSIS DEPICTS 3-5MB/3 HOUR PRESSURE RISES
ARE NOTED BEHIND THE FRONT FROM N TX INTO CNTRL OK/KS...WITH A
TIGHTENING PRESSURE GRADIENT BEHIND A SFC LOW OVER SW MO. IN
FACT...THE VISIBLE SATELLITE IMAGERY INDICATES NW TO SE STRIATIONS
IN THE STRATOCU FIELD OVER N TX/MUCH OF CNTRL AND ERN
OK...INDICATIVE OF THE STRONGER WINDS NEAR 2.5-3KFT. THESE
STRONGER WINDS SHOULD WORK INTO MCCURTAIN COUNTY OK AND THE WRN
SECTIONS OF E TX THIS AFTERNOON...AND FOR THAT REASON...HAVE
HOISTED A LAKE WIND ADVISORY FOR THESE AREAS THROUGH 10Z MONDAY.
WILL LIKELY HAVE TO EXPAND THE ADVISORY E INTO SW AR/WRN LA
LATER...BUT WILL ADDRESS THAT WITH THE AFTERNOON FORECAST PACKAGE.
HAVE ALSO RAISED TEMPS A FEW DEGREES ACROSS THE WARM SECTOR PER
THE 17Z OBS...WHILE ALSO REFLECTING A TEMP FALL FOR THE AFTERNOON
BEHIND THE FRONT. ALSO ADUSTED POPS AS WELL PER CURRENT RADAR
TRENDS.
ZONE UPDATE/NPW ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 65 31 47 28 56 / 90 10 0 0 0
MLU 68 35 45 27 53 / 80 30 0 0 0
DEQ 55 26 45 24 54 / 60 10 0 0 0
TXK 59 29 43 27 54 / 90 10 0 0 0
ELD 62 30 45 25 53 / 90 10 0 0 0
TYR 64 27 45 31 55 / 60 10 0 0 0
GGG 65 29 44 30 55 / 80 10 0 0 0
LFK 75 33 49 30 57 / 60 10 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: OKZ077.
TX...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: TXZ096-108>111-124-125-136-137-149-150.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1141 AM CST SUN FEB 1 2015
.DISCUSSION...
A 20-30NM WIDE BAND OF SHOWERS AND ISOLATED THUNDERSTORMS HAS
DEVELOPED ALONG A COLD FRONT...WHICH EXTENDS FROM NEAR LIT...TO
ADF...TO TXK...TO JXI/TYR...TO JUST E OF CRS AND TPL AS OF 17Z.
THIS CONVECTION HAS RESULTED IN 20-25KT WIND GUSTS ACROSS SW AR/NE
TX WITH ITS PASSAGE...ALTHOUGH WEAK CIN CONTRIBUTED BY THE LOW
LEVEL INVERSION NOTED ON THE 12Z KSHV RAOB CONTINUES TO HOLD
ACROSS SW AR/EXTREME NRN LA. FARTHER S...SOME BREAKS IN THE
STRATUS HAS BEEN NOTED...WITH LFK HAVING JUMPED INTO THE MID 70S.
SHOULD SEE SOME WEAK SFC BASED INSTABILITY DEVELOP THIS AFTERNOON
FROM LOWER TOLEDO BEND COUNTRY NE ACROSS NCNTRL LA AS SOME OF
THESE BREAKS MAY EXTEND NE OVER THESE AREAS...WITH CONTINUED
MOISTURE ADVECTION/BNDRY LYR HEATING CONTRIBUTING TO 500-800 J/KG
OF MLCAPE. FRONTAL CONVERGENCE REMAINS STRONG LATE THIS MORNING
WHERE THE CONVECTION IS ONGOING...WITH THE SHORT TERM PROGS
ACTUALLY MAINTAINING THE FRONTAL CONVERGENCE THROUGH THE AFTERNOON
WHERE A LITTLE BETTER INSTABILITY IS EXPECTED. HOWEVER...LAPSE
RATES ALOFT WILL BE QUITE MARGINAL...WITH THE BEST FORCING
EXPECTED TO BE ON THE NRN FRINGE OF THE WEAK INSTABILITY AXIS.
WHILE BRIEF WIND GUSTS TO 30-35KTS WILL BE POSSIBLE WITH THE
STRONGER CONVECTION...HAVE LOW CONFIDENCE IN SVR CONVECTION DEVELOPING
OVER THE AREA THIS AFTERNOON GIVEN THE VERY MARGINAL THERMODYNAMIC
ENVIRONMENT.
HOWEVER...THE FRONT IS MAKING A LITTLE FASTER PROGRESS SE THAN
EARLIER ANTICIPATED...WITH THE LATEST HRRR RUN HANDLING THE
FRONTAL PROGRESSION QUITE WELL. THE 12Z NAM IS ABOUT 3 HOURS
SLOWER...WITH THE GFS POSITION VERY SIMILAR IF NOT A TAD SLOWER
THAN THE HRRR. THUS...THE CONVECTION SHOULD MOVE OUT OF THE REGION
A LITTLE FASTER THAN EXPECTED LATER THIS AFTERNOON.
HOWEVER...THE MSAS ANALYSIS DEPICTS 3-5MB/3 HOUR PRESSURE RISES
ARE NOTED BEHIND THE FRONT FROM N TX INTO CNTRL OK/KS...WITH A
TIGHTENING PRESSURE GRADIENT BEHIND A SFC LOW OVER SW MO. IN
FACT...THE VISIBLE SATELLITE IMAGERY INDICATES NW TO SE STRIATIONS
IN THE STRATOCU FIELD OVER N TX/MUCH OF CNTRL AND ERN
OK...INDICATIVE OF THE STRONGER WINDS NEAR 2.5-3KFT. THESE
STRONGER WINDS SHOULD WORK INTO MCCURTAIN COUNTY OK AND THE WRN
SECTIONS OF E TX THIS AFTERNOON...AND FOR THAT REASON...HAVE
HOISTED A LAKE WIND ADVISORY FOR THESE AREAS THROUGH 10Z MONDAY.
WILL LIKELY HAVE TO EXPAND THE ADVISORY E INTO SW AR/WRN LA
LATER...BUT WILL ADDRESS THAT WITH THE AFTERNOON FORECAST PACKAGE.
HAVE ALSO RAISED TEMPS A FEW DEGREES ACROSS THE WARM SECTOR PER
THE 17Z OBS...WHILE ALSO REFLECTING A TEMP FALL FOR THE AFTERNOON
BEHIND THE FRONT. ALSO ADUSTED POPS AS WELL PER CURRENT RADAR
TRENDS.
ZONE UPDATE/NPW ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 65 31 47 28 56 / 90 10 0 0 0
MLU 68 35 45 27 53 / 80 30 0 0 0
DEQ 55 26 45 24 54 / 60 10 0 0 0
TXK 59 29 43 27 54 / 90 10 0 0 0
ELD 62 30 45 25 53 / 90 10 0 0 0
TYR 64 27 45 31 55 / 60 10 0 0 0
GGG 65 29 44 30 55 / 80 10 0 0 0
LFK 75 33 49 30 57 / 60 10 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: OKZ077.
TX...LAKE WIND ADVISORY UNTIL 4 AM CST MONDAY FOR THE FOLLOWING
ZONES: TXZ096-108>111-124-125-136-137-149-150.
&&
$$
15
AREA FORECAST DISCUSSION
NWS CARIBOU ME
928 PM EST MON FEB 2 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF NOVA SCOTIA OVERNIGHT. HIGH
PRESSURE WILL CROSS THE REGION TUESDAY. LOW PRESSURE WILL CROSS
THE REGION WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
915 PM UPDATE: 00Z SURFACE ANALYSIS HAD 985MB LOW MOVING TOWARD
THE SE TIP OF NOVA SCOTIA. HEAVIER BANDING STILL OCCURRING ON THE
NW SIDE OF THE STORM W/SOME HEAVY SNOWFALL OCCURRING ACROSS
PORTIONS OF EASTERN MAINE INCLUDING WASHINGTON COUNTY. RECEIVED
REPORTS OF 12-16 INCHES ACROSS THE DOWNEAST INCLUDING THE COAST.
AS ONE TRAVELS NORTH, REPORTS SHOW 6-9 INCHES W/UP TO 6 INCHES IN
SE AROOSTOOK COUNT. EARLIER REPORTS OF 1-2 INCHES PER HOUR
ESPECIALLY IN THE BANGOR AND BAR HARBOR REGION. BANDING HAS
SHIFTED E OF THE BANGOR AND BAR HARBOR AND THE LATEST TREND FROM
THE RAP AND NAM12 INDICATE THINGS TO WIND DOWN FROM SW TO NE OVER
THE NEXT 2 TO 4 HRS. WILL KEEP CURRENT HEADLINES IN PLACE TO COVER
FOR THE GUSTY WINDS AND HAZARDOUS TRAVEL EXPECTED.
PARTIAL CLEARING TUESDAY MORNING AS HIGH PRESSURE PUSHES INTO THE
AREA. SOME CLOUDS WILL THEN INCREASE LATE IN THE DAY AS A WEAK
SHORTWAVE APPROACHES FROM THE WEST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION TUESDAY NIGHT
WITH PARTLY/MOSTLY CLOUDY SKIES. LOW PRESSURE WILL APPROACH FROM
THE SOUTHWEST WEDNESDAY WITH INCREASING LIGHT SNOW CHANCES DURING
THE AFTERNOON. SNOW ACCUMULATIONS WEDNESDAY AFTERNOON WILL BE
LESS THAN AN INCH. THE LOW WILL CROSS THE REGION WEDNESDAY NIGHT
WITH ADDITIONAL LIGHT SNOW ACCUMULATIONS POSSIBLE MOSTLY
EARLY...WITH THE SNOW THEN TAPERING TO SNOW SHOWERS OVERNIGHT.
UNCERTAINTY THEN INCREASES THURSDAY REGARDING WHETHER HIGH
PRESSURE WILL BUILD ACROSS THE REGION OR WHETHER LOW PRESSURE
COULD BEGIN TO LIFT NORTH ALONG THE COAST. DUE TO THIS UNCERTAINTY
HAVE KEPT ONLY A CHANCE OF SNOW SHOWERS THURSDAY. HOWEVER...IF THE
DEVELOPING LOW SCENARIO IS CORRECT A STEADIER ACCUMULATING SNOW
WILL DEVELOP THURSDAY. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS
WEDNESDAY/THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MAIN CONCERN IN THE EXTENDED IS POTENTIAL FOR ANOTHER MAJOR STORM
AROUND THURSDAY NIGHT. HOWEVER, VERY LITTLE CONFIDENCE AT THIS
POINT. OPERATIONAL GFS AND CANADIAN MODEL AND MOST (BUT NOT ALL)
OF THEIR ENSEMBLES SEND THE WEDNESDAY TO EARLY THURSDAY SYSTEM FAR
ENOUGH OFFSHORE TO WHERE ANY LOW PRESSURE DEVELOPMENT ALONG THE
FRONT IS TOO FAR EAST TO IMPACT MAINE. HOWEVER, 0Z UKMET AND 0/12Z
ECMWF MODELS HANG THE ARCTIC FRONT JUST OFFSHORE WITH A NOR`EASTER
DEVELOPING ALONG THE FRONT IN RESPONSE TO A VIGOROUS SHORTWAVE
DIGGING SOUTHEAST FROM THE GREAT LAKES. HARD TO RECONCILE THE
DIFFERENCES...HIGH PRESSURE AND CLEAR VS LOW PRESSURE AND SNOWY
LATE THURSDAY INTO FRIDAY. AM QUITE HESITANT TO LEAN EITHER WAY AT
THIS POINT AND WENT WITH A CONSENSUS APPROACH. WILL BE EXTREMELY
INTERESTING TO WATCH MODEL TRENDS OVER THE NEXT DAY.
THE IMPACT OF AN ADDITIONAL POTENTIAL STORM WOULD BE VERY SIGNIFICANT
ESPECIALLY CONSIDERING THE EXTREME RECENT SNOWFALL. EASTPORT
RECEIVED 57.9 INCHES OF SNOW IN THE EIGHT DAYS FROM JAN 25 TO FEB
1, WITH ANOTHER 16 OR SO INCHES ON THE WAY TODAY INTO TONIGHT. THE
MACHIAS COOP OBSERVER`S 46.1 INCHES OF SNOW IN AN 8 DAY PERIOD
SHATTERS THAT COOP STATION`S 8-DAY RECORD OF 33.5 INCHES FROM
1964. RECORDS AT MACHIAS GO BACK TO 1893. THE EASTPORT 57.9 INCHES
IS FROM A COCORAHS OBSERVER, BUT A RECENTLY DECOMMISSIONED COOP
SITE IN EASTPORT HAS AN 8 DAY SNOWFALL RECORD OF 33 INCHES WITH
RECORDS FROM 1895 TO 2013, SO THE 57.9 INCHES WOULD SHATTER THAT.
BANGOR HAS HAD 31.4 INCHES IN THE 8 DAY PERIOD, WHICH IS NUMBER 3
FOR THEM, WITH THE RECORD 8 DAY SNOWFALL BEING 37 INCHES IN 1972.
SOUTHERN PORTIONS OF THE AREA ESPECIALLY ARE ALREADY HAVING A VERY
MEMORABLE PERIOD OF WEATHER WHICH IS GETTING MORE MEMORABLE BY THE
MOMENT WITH THE CURRENT STORM. I WOULD SAY THE CURRENT MONDAY STORM
IS PUSHING DOWNEAST MAINE TO THE LIMIT, NOT TO MENTION ANOTHER
POTENTIAL STORM AFTER THIS ONE.
THE MODEL DISAGREEMENTS CONTINUE INTO THE WEEKEND. GFS/CANADIAN
HAVE A FAIRLY WEAK CLIPPER SYSTEM SATURDAY AND SATURDAY NIGHT
WHILE THE ECMWF IS JUST COLD AND DRY. EITHER WAY, SUNDAY INTO
EARLY NEXT WEEK LOOK COLDER THAN NORMAL, NOT THAT IS HASN`T BEEN
COLDER THAN NORMAL ALREADY AS OF LATE. CANNOT TOTALLY RULE OUT
STORMINESS PERSISTING INTO EARLY NEXT WEEK, BUT MODELS ARE IN
EXTREMELY POOR AGREEMENT SO HESITANT TO SAY MUCH AT THIS POINT.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR CONDITIONS IN SNOW TONIGHT WILL IMPROVE TO MVFR
LATE THIS EVENING THEN VFR LATE TONIGHT. VFR CONDITIONS ARE
EXPECTED ON TUESDAY.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT. CONDITIONS
WILL THEN LOWER TO MVFR/IFR LEVELS WEDNESDAY...WITH SIMILAR
CONDITIONS PERSISTING INTO WEDNESDAY NIGHT. CONDITIONS THURSDAY
INTO SATURDAY WILL BE DEPENDENT ON WHETHER HIGH PRESSURE IS ABLE
TO BUILD ACROSS THE REGION OR WHETHER LOW PRESSURE LIFTS NORTH
ACROSS THE FORECAST AREA WHICH IS UNCERTAIN AT THIS TIME.
&&
.MARINE...
NEAR TERM: A GALE WARNING IS UP FOR THE WATERS INTO TUESDAY
MORNING. ALSO, A HEAVY FREEZING SPRAY WARNING WILL BE ISSUED FOR
HEAVY FREEZING SPRAY TONIGHT INTO EARLY TUESDAY MORNING AS
DEPARTING LOW PRESSURE PULLS BITTERLY COLD AIR OVER THE WATERS ON
GUSTY NORTH TO NORTHWEST WINDS. WINDS WILL DIMINISH TUESDAY
AFTERNOON.
SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TUESDAY
NIGHT THROUGH THURSDAY. VISIBILITIES WILL BE REDUCED IN SNOW
WEDNESDAY INTO WEDNESDAY NIGHT WITH A CHANCE OF SNOW SHOWERS
THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 5 AM EST TUESDAY FOR MEZ002-004.
WIND CHILL ADVISORY UNTIL 11 AM EST TUESDAY FOR MEZ001-003.
WINTER STORM WARNING UNTIL 5 AM EST TUESDAY FOR MEZ005-006-010-
011-015>017-029>032.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 8 AM EST TUESDAY FOR
ANZ050>052.
GALE WARNING UNTIL 9 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
412 PM EST SUN FEB 1 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 411 PM EST SUN FEB 1 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A TROUGH FROM NRN HUDSON BAY INTO ERN CANADA
RESULTING IN WNW NRN STREAM FLOW THROUGH THE NRN GREAT LAKES. TO THE
SOUTH...A VIGOROUS SHRTWV TROUGH INTO NRN IL WAS BRINGING HEAVY SNOW
FROM IA INTO THE SRN LAKES. AT THE SFC...DRY NE FLOW PREVAILED
THROUGH LAKE SUPERIOR AND UPPER MI BETWEEN A 1036 MB HIGH OVER ERN
NORTH DAKOTA AND A 1003 MB LOW OVER ERN IL. 900 MB TEMPS AROUND -22C
PROVIDED ENOUGH INSTABILITY FOR PERSISTENT LES. HOWEVER...INVERSION
HEIGHTS AROUND 3K FT AND A DGZ BELOW 1K FT HAS LIMITED INTENSITY AND
ACCUMULATION POTENTIAL.
TONIGHT...EXPECT THE WINDS TO GRADUALLY BACK TO NRLY AS THE IL LOW
MOVES TO THE E AND THE HIGH BUILDS INTO THE CNTRL PLAINS. WITH A
RELATIVELY LIGHT WIND FIELD...LAND BREEZE EFFECTS AND THE
DEVELOPMENT OF LOCALIZED CIRCULATIONS OR AREAS OF CONVERGENCE WILL
BE MORE LIKELY. THE HIGHER RES MODELS SUGGEST THAT A BAND MAY
DEVELOP THAT WOULD AFFECT FAR ERN OR WRN ALGER COUNTY TONIGHT.
INVERSION HEIGHTS REMAINING AROUND 3K FT SHOULD LIMIT ACCUMULATION
POTENTIAL TO A FEW INCHES. THERE MAY ALSO BE A SHORELINE PARALLEL
BAND NEAR THE WEST BUT CONFIDENCE IN WHERE IT MAY AFFECT THE
SHORELINE IS LOW.
BESIDES THE LES...TEMPS WILL FALL BELOW ZERO TONIGHT...ESPECIALLY
OVER THE FAR ERN COUNTIES AND ALONG THE WI BORDER OF THE INTERIOR WEST.
FORTUNATELY...WITH THE LIGHT WINDS AND SOME LAKE MODERATION/LAKE
EFFECT CLOUDS...WIND CHILLS SHOULD REMAIN IN THE -10 TO -20
RANGE...NOT REACHING ADVY CRITERIA.
MON...SOME LINGERING LES IN THE N TO NW SNOWBELTS AS 900 MB TEMPS
WILL BE AROUND -22C WILL BE PUSHED OFFSHORE AS A TROUGH DEVELOPS
OVER NRN MN INTO NRN LAKE SUPERIOR AND THE HIGH PRES SHIFTS TO THE
OH VALLEY. TEMPS WILL REMAIN BELOW NORMAL IN THE 10-15F RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EST SUN FEB 1 2015
COLD CONDITIONS WITH BELOW NORMAL TEMPS EXPECTED THIS WEEK AS
RIDGING FROM EASTERN RUSSIA AND THE BERING SEA TO THE WESTERN CONUS
ALLOWS TROUGHING TO EXPAND ACROSS THE GREAT LAKES FM EASTERN CANADA.
RIDGING BEGINS TO FLATTEN BY END OF THE EXTENDED PERIOD SUGGESTING
THAT TEMPS WILL BOUNCE BACK TOWARD NORMAL OR MAYBE ABOVE BEYOND NEXT
WEEKEND. DAYTIME HIGHS FOR A COUPLE DAYS WILL STAY IN THE SINGLE
DIGITS BUT OTHERWISE WILL BE IN THE TEENS. NIGHTTIME LOWS WILL MAINLY
BE IN THE SINGLE DIGITS BLO ZERO TO THE SINGLE DIGITS ABOVE. MAY HAVE
TO DEAL WITH WIND CHILL ISSUES...ESPECIALLY ON THURSDAY MORNING.
COLDEST DAYS LIKELY WEDNESDAY AND THURSDAY AS CORE OF ARCTIC AIR WITH
H85 TEMPS BLO -25C SWEEPS OVER THE UPPER GREAT LAKES. WIDESPREAD SNOW
CHANCES STILL ON THE LOWER SIDE IN THIS PATTERN. FOR LAST COUPLE
DAYS...PRIMARY EXTENDED MODELS OF ECMWF/GFS AND GEM-NH ALONG WITH GFS
ENSEMBLES HAVE HINTED AT BETTER SHOT OF SNOW OVER MUCH OF THE UPPER
LAKES REGION FRIDAY AFTERNOON INTO SATURDAY AS A COLD FRONT SLIDES
ACROSS THE AREA. DETAILS STILL NEED TO BE SORTED OUT THOUGH AS MODEL
CONSISTENCY IS LACKING.
AT THE BEGINNING OF THE LONG TERM...HIGH PRESSURE CENTER SETTLES TO
THE LOWER MISSISSIPP RIVER VALLEY ON MONDAY EVENING. A TROUGH WILL
BE APPROACHING LK SUPERIOR FM NORTHERN ONTARIO. WEAK SHORTWAVE/PV
ANAMOLY SLIDES THROUGH AND SOUNDINGS EVEN INLAND SHOW MARGINAL DEEP
MOISTENING H8-H5 WITH WEAK LIFT. LGT SNOW OR FLURRIES MOST AREAS
LATER MONDAY EVENING INTO THE OVERNIGHT. BIGGER IMPACT MAY OCCUR
OVER NORTHERN KEWEENAW PENINSULA AS BAND OF MODERATE TO POSSIBLY
HEAVY LES COULD BE ONGOING. LIFT FM THE DISTURBANCE ALONG WITH H85
TEMPS NEAR -20C YIELDS 1000-850MB LAPSE RATES OVER 9C/KM WHERE
STRONGER CONVERGENCE COMES TOGETHER. LOCAL HIRES WRF MODEL SEEMS
REASONABLE SHOWING OVER 0.05 INCH OF QPF PER HOUR IN HEAVIER
BANDING. SO WITH SLR/S OVER 20:1...COULD BE OVER 1 INCH OF SNOW PER
HOUR...WHICH FITS THIS TYPE OF LES REGIME. DOES APPEAR THAT WITH
ARRIVAL OF TROUGH THE HEAVIEST SNOW WILL NOT LAST PROBABLY MORE THAN
A FEW HOURS. WIND GUSTS 20-25 MPH WILL BLOW/DRIFT SNOW AS WELL.
OVERALL...SEEMS LIKE MODELS/PATTERN RECOGNITION POINTS TO ADVY FOR
TIP OF KEWEENAW MONDAY EVENING...BEFORE THE LES SINKS ACROSS REST OF
KEWEENAW AND BECOMES MORE MULTIBAND IN TYPE. CONTINUE TO MENTION IN
HWO.
ONCE THE SFC TROUGH MOVES THROUGH LATE MONDAY NIGHT INTO TUESDAY
MORNING AND LARGER SCALE FORCING EVADES...EXPECT NW FLOW LES THROUGH
TUESDAY NIGHT. LOW INVERSIONS BLO 4KFT AND NEUTRAL TO ANTICYLONIC
FLOW WILL LIMIT INTENSITY OF LES DESPITE ALL OF THE CLOUD BEING
WITHIN THE DGZ. FLUFFY ACCUMS EXPECTED BUT LOW IMPACT AS WINDS WILL
BE LIGHT. AS THIS OCCURS...LOW PRESSURE SYSTEM MOVES OVER THE
NORTHERN PLAINS AND EVENTUALLY SPREADS LGT SNOW OVER THE WESTERN
GREAT LAKES REGION ON TUESDAY NIGHT. NAM FARTHER NORTH WITH THE QPF
COMPARED TO THE MORE CONSISTENT ECWMF/GFS AND GEM-NH. WILL SHOOT FOR
A MAINLY DRY FORECAST AWAY FM THE LK SUPERIOR LES.
PRIMARY HAZARDOUS WEATHER POTENTIAL WILL BE TIED TO LAKE EFFECT AND
BLSN/DRSN THAT RAMPS UP WEDNESDAY AND WEDNESDAY NIGHT FOR AREAS NEAR
LK SUPERIOR FAVORED BY NORTHWEST WINDS. THIS IS IN WAKE OF THE LOW
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT THAT CROSS THE AREA ON
TUESDAY NIGHT. INVERSION HEIGHTS RISING TO AT LEAST 8KFT AND LAKE
EQL OVER 10KFT POINT TO MODERATE TO HEAVY SNOW. DUE TO DEPTH OF COLD
THOUGH...SOUNDINGS INDICATE MOST OF THE LAKE EFFECT CONVECTIVE LAYER
WILL BE AT TEMPS BLO -20C. SO...LOOKING AT SMALL SNOW FLAKES GOOD AT
REDUCING VSBY...BUT NOT PILING UP A LOT OF SNOW. WINDS IN THE MIXED
LAYER 25-30 KTS...SO BLSN/DRSN WILL BE PREVALENT WITH THE FINE SNOW
FLAKES. EXPECT THERE WILL NEED TO BE SOME WINTER WEATHER HEADLINES
CENTERED ON WEDNESDAY INTO WEDNESDAY NIGHT.
AWAY FM THE LES AND BLSN/DRSN...APPEARS CONDITIONS OVER AT LEAST
INTERIOR WEST WILL BE CLOSE TO WIND CHILL ADVISORY CRITERIA LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING. EXPECT READINGS 20 TO 25 BLO
ZERO WHICH IS CLOSE TO...BUT NOT QUITE REACHING CRITERIA OF 25 TO 35
BLO. WILL CONTINUE TO MENTION THIS IN THE HWO...BUT IS NOT APPEARING
TO BE AN OVERWHELMING LOW WIND CHILL EVENT.
ANOTHER TROUGH...REALLY MORE OF A WARM FRONT ALOFT...SLIDES OVER
NORTHERN ONTARIO AND LK SUPERIOR THURSDAY AFTN THROUGH THURSDAY
NIGHT. WINDS BACKING SW AHEAD OF THE TROUGH IN LOW-LEVELS WILL PUSH
LES OVER LK SUPERIOR AND WINDS APPEAR TO HAVE TOO MUCH WESTERLY
COMPONENT TO RESULT IN LES OFF LK MICHIGAN FM KISQ TO KERY. MID-
LEVEL MOISTURE WITH WEAK LIFT MAY SQUEEZE OUT LGT SNOW OR FLURRIES
FOR MOST OF THE CWA.
CONSISTENCY NOT THERE YET FOR FRIDAY AND SATURDAY SO WILL RUN WITH
FORECAST CONSENSUS ATTM. BEST CHANCES OF A WIDESPREAD SNOW PROBABLY
FRIDAY NIGHT WITH INCREASING UNCERTAINTY FOR THAT ON SATURDAY. FRONT
WILL BE IN THE VCNTY AND LATEST INDICATIONS FM MODELS AND HAND DRAWN
PROG FM WPC SHOWS IT MAINLY SOUTH OF AREA ON SUNDAY WITH LOW CHANCES
FOR LES IN AN EASTERLY FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1251 PM EST SUN FEB 1 2015
MVFR CONDITIONS WITH OCNL IFR VSBY IN LAKE CLOUDS AND LIGHT SNOW
SHOWERS WILL CONTINUE AT KSAW AND KCMX THROUGH MUCH OF THE PERIOD IN
A NE-N FLOW. KIWD WILL SEE VFR CONDITIONS EARLY THIS AFTERNOON
MORNING BEFORE TRANSITIONING TO MVFR CONDITIONS THIS AFTERNOON AS
WINDS SHIFT FROM ENE TO MORE ONSHORE NNE FLOW. WITH ONSHORE FLOW
THIS AFTERNOON INTO TONIGHT...EXPECT MVFR CLOUD DECK AND POSSIBLE
LIGHT SNOW SHOWERS AT KIWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EST SUN FEB 1 2015
NORTHEAST WINDS BECOME WEST AHEAD OF APPROACHING TROUGH ON
MONDAY...THEN TURN TO THE NORTHWEST BEHIND THE TROUGH ON TUESDAY.
WINDS THROUGH TUESDAY AT OR BLO 30 KTS. HEAVY FREEZING SPRAY OVER
PORTIONS OF LK SUPERIOR ON MONDAY NIGHT. STRONG COLD FRONT MOVES
ACROSS LK SUPERIOR TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. NW
WINDS COULD REACH LOW-END GALES IN GUSTS WEDNESDAY AND WEDNESDAY
EVENING. HEAVY FREEZING SPRAY IS EXPECTED DURING THIS
TIME...ESPECIALLY FOR EAST HALF OF LK SUPERIOR. WINDS BACK SW ON
THURSDAY AHEAD OF ANOTHER TROUGH THAT CROSSES ON FRIDAY...THEN
BECOME NORTHERLY BEHIND THE TROUGH INTO NEXT WEEKEND. WINDS SHOULD
STAY AT OR BLO 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
310 PM EST SUN FEB 1 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/CLIMATE
.SYNOPSIS...
ISSUED AT 305 PM EST SUN FEB 1 2015
A MAJOR WINTER STORM WILL CONTINUE TO IMPACT THE REGION THROUGH
EARLY MONDAY MORNING BEFORE DEPARTING. BLOWING AND DRIFTING SNOW
WILL CONTINUE TO LEAD TO DANGEROUS TRAVEL ESPECIALLY NEAR AND
SOUTH OF I-96 AND TOWARD I-94. STORM TOTAL ACCUMULATIONS
(INCLUDING WHAT HAS FALLEN ALREADY) BY MONDAY MORNING WILL RANGE FROM A
COUPLE INCHES ALONG ROUTE 10 TO AS MUCH AS 12 TO 16 INCHES ALONG
I-94. WIND CHILL READINGS WILL FREQUENTLY BE BELOW ZERO FOR MOST
MORNINGS THIS WEEK. OCCASIONAL SNOW SHOWERS ARE POSSIBLE THROUGH
MID WEEK WITH ADDITIONAL SNOW SHOWERS ONCE AGAIN FOR THE WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 305 PM EST SUN FEB 1 2015
STORM TERM DISCUSSION: LITTLE CHANGE TO OUR EXISTING
FORECAST...WITH CONTINUED SNOW AND BLOWING SNOW THROUGH TONIGHT
WITH SNOW COVERED ROADS AND DRIFTING SNOW LEADING TO DANGEROUS
TRAVEL. RESIDUAL IMPACTS TO THE MONDAY MORNING COMMUTE ARE
LIKELY...ESPECIALLY FOR SECONDARY AND RURAL ROADS WHERE UNPLOWED
SNOW MAY BE A SIGNIFICANT PROBLEM FOR TRAVEL. THE GFS HAS LED THE
WAY WITH THIS SYSTEM AND WILL CONTINUE TO BE FOLLOWED CLOSELY. WV
AND IR IMAGERY SHOW THE WESTERN EDGE OF THIS STORM STILL EXTENDS
INTO EASTERN NEBRASKA AND WESTERN IOWA...SO STILL A WAYS TO GO YET
AS THE DEFORMATION ZONE WORKS INTO THE SOUTHERN CWA TONIGHT.
LOOKING AT THE 12Z GFS MULTI- LAYER FN VECTOR CONVERGENCE FROM
H925 UP TO H500...THERE ARE INDICATIONS THAT BOTH THE I-94 REGION
AND ALSO A SEPARATE AREA FROM SOUTH HAVEN TO GRR WILL BE
UNDERNEATH DEEP FORCING...WITH SOME MESOSCALE HEAVY BANDS POSSIBLE
WITH ENHANCED SNOWFALL RATES OF 1" OR MORE PER HOUR. THAT
SAID...THIS IS A VERY FINE SNOW...AND SETTLING/COMPRESSION
UNDOUBTEDLY WILL OCCUR. NEVERTHELESS...AMOUNTS WILL CONTINUE
PILING UP THROUGH TONIGHT AS THE WORST OF THE STORM IS EXPECTED TO
MANIFEST FROM 21Z THROUGH 06Z.
THE DRY SLOT IS EXPECTED TO MOVE AS FAR NORTH AS EXTREME SE
MICHIGAN...AND AS SUCH...WEAKLY POSITIVE OR EVEN NEGATIVE EPV ON
THE NOSE OF THIS DRY SLOT WILL IMPACT AREAS ALONG/EAST OF AN AZO TO
LAN LINE THROUGH 06Z. THIS WILL BE COINCIDENT WITH COMPLETE
SATURATION THROUGH THE COLUMN AND ALSO STRONG FGEN WITH THE
DEFORMATION ZONE FORECAST TO MOVE INTO THE SOUTHERN/SE CWA BY BOTH
THE NAM AND GFS. ALL THIS ADDS CONFIDENCE TO STEADY SNOWFALL RATES
OF AROUND OR EVEN A BIT MORE THAN 1"/HOUR TONIGHT NEAR AND SOUTH
OF I-96 AND PARTICULARLY NEAR/EAST OF AN AZO TO LAN LINE. BY 00Z
OR SHORTLY THEREAFTER...THE DGZ SPLITS INTO TWO REGIONS AS LOW
LEVEL TEMPS CONTINUE TO DECLINE...SO A "BONUS" REGION FOR
DENDRITIC GROWTH WILL EXIST FOR A SHORT TIME BEFORE THE STORM
WINDS DOWN. NOT SURE HOW MUCH THIS WILL ADD TO THE ACCUMS...BUT
SOME ENHANCEMENT IS POSSIBLE.
AMOUNTS SO FAR NEAR/SOUTH OF I-96 HAVE GENERALLY BEEN 4 TO 8
INCHES. AN ADDITIONAL 4 TO 8 INCHES IS EXPECTED TONIGHT...BRINGING
STORM TOTAL ACCUMULATIONS IN THE 8 TO 16 INCH RANGE. THIS IS BASED
ON A WEIGHTED BLEND OF ALL AVAILABLE SHORT/LONG RANGE MODELS AS
WELL AS WPC GUIDANCE. NORTH OF I-96...WHERE AN ADVISORY IS IN
PLACE...STORM TOTAL AMOUNTS WILL TAIL OFF TO AROUND 8 INCHES
ACROSS THE VERY SOUTHERN PORTION OF THE ADVISORY AREA TO AS LITTLE
AS 2 OR 3 INCHES NEAR ROUTE 10.
WINDS...AS ANTICIPATED...HAVE BEEN ON THE UPSWING TODAY. GRR AND
MKG HAVE ALREADY GUSTED TO 30 KNOTS OR GREATER. ALTHOUGH HRRR WIND
GUSTS ARE TOO HIGH BY 5-10 KNOTS...WILL KEEP THE GENERAL THEME IN
MIND WITH OUR GRIDS AND HOLD ONTO GUSTY WINDS THROUGH AT LEAST
06Z. WIND GUSTS TO 40 MPH ARE POSSIBLE BASED ON TRENDS THIS
AFTERNOON...MAINLY FROM MKG TO GRR TO LAN...WHERE NE FLOW SEEMS TO
BE MAXIMIZED IN THESE TYPES OF SYSTEMS. BLOWING AND DRIFTING
SNOW...ESPECIALLY IN RURAL/OPEN AREAS...WILL BE A SIGNIFICANT
PROBLEM FOR THE DURATION OF THIS EVENT GIVEN THE DRY NATURE OF THE
SNOW AND THE WIND GUSTS.
SHORT TERM DISCUSSION: AFTER THE STORM MOVES OUT AROUND
12Z...EXPECTING A MUCH QUIETER MONDAY ASIDE FROM SOME LAKE EFFECT
SNOW SHOWERS THAT WILL BLOW INLAND AS WINDS BACK FROM N TO W WITH
A RIDGE MOVING INTO THE OHIO VALLEY REGION. ACCUMS ARE ONLY
EXPECTED TO BE A FEW TENTHS OF AN INCH. BY TUESDAY NIGHT...A
CLIPPER WILL BE MOVING THROUGH THE MIDWEST AND WILL SPREAD SOME
LIGHT SNOW INTO SOUTHERN LOWER MICHIGAN. LIGHT ACCUMULATIONS LOOK
PROBABLE AT THIS POINT BASED ON MEDIUM RANGE MODEL QPF.
&&
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 305 PM EST SUN FEB 1 2015
A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL LINGER WEDNESDAY AS A
STRONG UPPER LEVEL PV ANOMALY MOVES ACROSS THE NORTHERN GREAT LAKES
REGION AND IN THE WAKE OF THE ARCTIC COLD FRONT. WIDESPREAD SUB ZERO
READINGS ARE QUITE POSSIBLE BY EARLY THURSDAY MORNING AS A RESULT OF
CLEARING SKIES AND A DRY AIRMASS IN PLACE AS HIGH PRESSURE BUILDS IN
IN CONJUNCTION WITH WITH EXTENSIVE SNOW COVER ACROSS MUCH OF OUR
FCST AREA BY THEN.
HIGH PRESSURE WILL BRING FAIR WEATHER THURSDAY BUT IT WILL BE QUITE
COLD WITH MAX TEMPS ONLY REACHING THE TEENS. TEMPS WILL MODERATE
FRIDAY AND SATURDAY AS THE UPPER LEVEL PATTERN BECOMES ZONAL. A
COLD FRONT DROPPING DOWN FROM THE NW WILL BRING A CHANCE OF LIGHT
SNOW FRIDAY NIGHT AND/OR SATURDAY FOLLOWED BY THE ARRIVAL OF ANOTHER
COLDER AIRMASS BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1145 AM EST SUN FEB 1 2015
A SNOWSTORM WILL CONTINUE IN PROGRESS THIS AFTERNOON THROUGH THIS
EVENING RESULTING IN WIDESPREAD LIFR CONDITIONS THROUGH LATE THIS
EVENING DUE TO MODERATE TO HEAVY SNOW AND BLOWING SNOW. NORTHEAST
WINDS WILL CONTINUE TO INCREASE TO 15 TO 25 KTS WITH FREQUENT GUSTS
TO AROUND 30 KTS LATE THIS AFTERNOON AND EVENING WHICH WILL FURTHER
REDUCE VISIBILITIES IN BLOWING SNOW. LIGHT RIME ICING WILL BE
POSSIBLE GENERALLY BELOW 2000 FT AGL.
CONDITIONS WILL GRADUALLY IMPROVE TO IFR THEN MVFR DURING THE EARLY
MORNING HOURS MONDAY AS THE SNOW MOVES OUT AND CIGS BEGIN TO
IMPROVE. NORTH WINDS WILL REMAIN BRISK AT 15 TO 25 KTS OVERNIGHT.
CONDITIONS WILL GRADUALLY IMPROVE TO VFR MID TO LATE MONDAY MORNING
WHEN WIND SPEEDS WILL DIMINISH A LITTLE BIT OUT OF THE NNW AT 15 TO
20 KTS. CONDITIONS SHOULD THEN REMAIN VFR THROUGH 18Z MON.
&&
.HYDROLOGY...
ISSUED AT 300 PM EST SUN FEB 1 2015
ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
HAS ARRIVED WITH THE COLDEST TEMPS EXPECTED MONDAY WITH SIMILAR
TEMPS FOR THURSDAY AS ANOTHER ARCTIC FRONT MOVES THROUGH. LOWS
TONIGHT AND MONDAY MORNING WILL DROP INTO THE SINGLE DIGITS. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK SO ICE
DEVELOPMENT WILL CONTINUE...PLUS THE SNOW THAT FALLS THROUGH
MONDAY MORNING WILL ALSO HELP WITH ICE DEVELOPMENT. ICE IS
EXPECTED TO REMAIN FAIRLY STABLE AS TEMPS STAY CHILLY.
&&
.CLIMATE...
ISSUED AT 153 PM EST SUN FEB 1 2015
FEB 1ST RECORD SNOWFALL FOR GRR IS 6.1" IN 2001.
FEB 1ST RECORD SNOWFALL FOR LAN IS 6.2" IN 1967.
FEB 1ST RECORD SNOWFALL FOR MKG IS 14.2" IN 1965.
WHILE OFFICIAL LONG TERM SNOWFALL RECORDS ARE NOT MAINTAINED
OUTSIDE OF THESE LOCAL CLIMATOLOGICAL DATA (LCD) STATIONS...SNOWFALL
AMOUNTS OF 10" OR MORE IN A SINGLE CALENDAR DAY WILL LIKELY RANK
IN THE TOP 10 OR TOP 5 FOR THE ENTIRE MONTH OF FEBRUARY FOR MANY
LOCATIONS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
064>067-071>074.
WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
043>046-050>052.
LM...NONE.
&&
$$
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW/HOVING
CLIMATE...HOVING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
419 AM EST SUN FEB 1 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT JAN 31 2015
THIS AFTERNOON THROUGH SUNDAY...HIGH PRESSURE SLIDING ACROSS CENTRAL
CANADA THIS AFTERNOON HAS ALLOW NORTHERLY FLOW TO INCREASE ACROSS
MUCH OF THE UPPER GREAT LAKES REGION. THIS NORTHERLY FLOW COUPLED
WITH 850MB TEMPERATURES COOLING TO AROUND -18C TO -20C HAS ALLOWED
LAKE EFFECT SNOW TO DEVELOP AHEAD OF THE SURFACE HIGH PRESSURE
SYSTEM. INITIALLY...DEEPER MOISTURE WILL LINGER INTO THE EARLY
EVENING HOURS ALLOWING BETTER SNOW GROWTH WITH A THICKER SNOW GROTH
AREA WITHIN THE DGZ. RUC SOUNDINGS SHOW INVERSION HEIGHTS BETWEEN
4KFT AND 5KFT THIS AFETERNOON WHICH IS ALSO VERIFIED BY THE MQT VAD
WIND PROFILE THIS AFETERNOON. THIS HAS ALLOWED GOOD SNOWFLAKE SIZE
THIS AFTERNOON RESULTING IN A QUICK INCH OR TWO OF FLUFFY SNOW ON A
NORTH TO NORTHWESTERLY WIND. DRY AIR REMAINS JUST TO THE NORTH OF
THE AREA THIS AFTERNOON...HOWEVER...THIS IS EXPECTED TO SHIFT
FARTHER SOUTH AROUND 00Z/01 AS INVERSION HEIGHTS BEGIN TO FALL TO
AROUND 3KFT. THIS SHOULD HELP TO REDUCE SNOWFALL RATES THIS EVENING
INTO THE OVERNIGHT HOURS.
AS THE SURFACE RIDGE EXPANDS TO THE NORTH OF LAKE SUPERIOR EXPECT
WINDS TO SHIFT TO THE NORTH AND NORTHEAST SHIFTING THE SNOWBANDS TO
THE NORTH TO NORTHEAST WIND FAVORED SNOW BELTS. AGAIN...REDUCED
MOISTURE...LOWERED INVERSION HEIGHTS ALONG WITH ANTICYCLONIC FLOW
WILL HELP TO KEEP SNOWFALL TOTALS IN CHECK ACROSS THE U.P. WITH UP
TO 2 INCHES EXPECTED ALONG THE NORTH TO NORTHEAST WIND FAVORED SNOW
BELTS. AS THE SURFACE RIDGE CENTER SHIFTS INTO THE NORTHERN PLAINS
ON SUNDAY EXPECT WINDS TO SHIFT TO A MORE NORTHERLY DIRECTION.
TEMPERATURES ALOFT WILL REMAIN COLD ENOUGH AND LOW LEVEL MOISTURE
OFF LAKE SUPERIOR WILL KEEP LAKE EFFECT SNOW IN NORTHERLY WIND
FAVORED LOCATIONS...WITH AROUND AN INCH ACCUMULATION EXPECTED IN
THESE AREAS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 418 AM EST SUN FEB 1 2015
GREATEST RISK OF HAZARDOUS WEATHER IN THE EXTENDED IN NW WIND
SNOWBELTS WED THROUGH WED NIGHT AND POSSIBLY ACROSS THE KEWEENAW
PENINSULA LATE MON INTO MON NIGHT. MAY SEE WIND CHILL VALUES NEAR
ADVISORY CRITERIA THU MORNING.
MON MORNING WILL SEE ONGOING LES IN THE N TO NW SNOWBELTS AS 850MB
TEMPS WILL BE AROUND -22C. A SFC RIDGE WILL BE OVER WRN LAKE
SUPERIOR BY 12Z MON...BUT WILL BE PUSHED QUICKLY E AS A SFC TROUGH
MOVES/DEVELOPS INTO THE AREA ON MON. WITH THE TROUGH MOVING INTO NRN
LAKE SUPERIOR AS THE RIDGE SUPPRESSES SOUTHWARD...W TO WSW LOW LEVEL
FLOW RESULTS BY MON AFTERNOON AND CONTINUES UNTIL LATE MON NIGHT
WHEN ADDITIONAL ENERGY IS ADDED TO THE TROUGH /PUSHING IT SLIGHTLY
SE/ AND FLOW VEERS TO A WNW DIRECTION. THE FLOW DIRECTION FAVORS THE
KEWEENAW FOR THE BEST SNOW...BUT EXACTLY HOW LONG THE STRONGER
BAND/S/ LINGER IN ANY LOCATION IS MORE UNCERTAIN. AT THIS
TIME...MODEL WIND FIELDS DO SUPPORT THE IDEA OF SEEING A FEW INCHES
OF SNOW OVER THE KEWEENAW...ESPECIALLY THE NRN/WRN KEWEENAW...LATE
MON INTO TUE MORNING. THIS IS BACKED UP BY MODEL QPF FROM THE NAM
AND GFS. THE 00Z/01 NAM HAS UP TO 0.15 INCHES...WHICH WOULD BE
UNDERDONE IF THE SCENARIO DOES OCCUR...AND THE 00Z/01 GFS HAS 0.07
INCHES OF QPF...WHICH WOULD BE WELL UNDERDONE DUE TO MODEL
RESOLUTION.
WNW FLOW LES IS EXPECTED TUE INTO TUE NIGHT AS THE SFC TROUGH
LINGERS...BUT A COLD FRONT/TROUGH WILL MOVE IN WITH A SYSTEM LATE
TUE NIGHT AND WED AND WILL BRING EVEN COLDER AIR TO THE REGION.
MODERATE TO LOCALLY HEAVY SNOW IS PROBABLE ALONG THE FRONT WHILE IN
THE NW WIND SNOWBELTS. BEHIND THE FRONT...MODERATE LES WILL CONTINUE
AT LEAST INTO WED NIGHT AS 850MB TEMPS WILL BE AS LOW AS -27C. THERE
IS UNCERTAINTY AS TO WHEN CONDITIONS MODIFY ON THE BACK SIDE OF THE
SYSTEM AS THE ECMWF BRINGS SIGNIFICANTLY WARMER AIR WITH WSW FLOW BY
12Z THU WHILE THE GFS IS ABOUT 12 HOURS SLOWER IN DOING SO. WITH
THAT COLD OF AN AIRMASS...WE WILL BE LOOKING AT SMALL SNOW FLAKES
THAT ARE EFFICIENT AT REDUCING VIS. COULD SEE HEADLINE WORTHY
CONDITIONS DURING THIS TIME PERIOD...MAINLY IN THE NW WIND SNOWBELTS.
LOOKS LIKE WSW FLOW AND WAA CONTINUE THROUGH THU NIGHT...BUT MODELS
VARY SIGNIFICANTLY FROM RUN TO RUN AND FROM MODEL TO MODEL AFTER
THAT...SO WILL JUST USE A CONSENSUS APPROACH FOR FRI THROUGH SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1155 PM EST SAT JAN 31 2015
MVFR CONDITIONS WILL CONTINUE FOR ALL SITES THIS FORECAST PERIOD
WITH NORTHEAST UPSLOPE WINDS. SNOW SHOWERS WILL BE PERIODIC AT SAW
AND CMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT JAN 31 2015
A COLD FRONT THAT SHIFTED SOUTH AND EAST OF THE AREA THIS AFTERNOON
ALONG WITH A DECENT PRESSURE GRADIENT ON THE BACK SIDE WILL ALLOW A
FEW GUSTS TO REACH 35KTS THIS AFTERNOON AND EVENING. MUCH LIGHTER
WINDS WILL PREVAIL SUNDAY AS HIGH PRESSURE DRIFTS ACROSS THE UPPER
GREAT LAKES REGION. LOW PRESSURE AND ASSOCIATED COLD FRONT WILL
APPROACH THE AREA MONDAY NIGHT AND THEN SWEEP THROUGH THE AREA
TUESDA NIGHT AND WEDNESDAY. ON THE BACK SIDE OF THIS SYSTEM...WINDS
WILL INCREASE FROM THE NORTHWEST WEDNESDAY AFTERNOON THROUGH
THURSDAY...WITH GALE FORCE GUSTS TO 35 KNOTS POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KEC
LONG TERM...TITUS
AVIATION...07
MARINE...KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 PM EST SAT JAN 31 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM EST SAT JAN 31 2015
THIS AFTERNOON THROUGH SUNDAY...HIGH PRESSURE SLIDING ACROSS CENTRAL
CANADA THIS AFTERNOON HAS ALLOW NORTHERLY FLOW TO INCREASE ACROSS
MUCH OF THE UPPER GREAT LAKES REGION. THIS NORTHERLY FLOW COUPLED
WITH 850MB TEMPERATURES COOLING TO AROUND -18C TO -20C HAS ALLOWED
LAKE EFFECT SNOW TO DEVELOP AHEAD OF THE SURFACE HIGH PRESSURE
SYSTEM. INITIALLY...DEEPER MOISTURE WILL LINGER INTO THE EARLY
EVENING HOURS ALLOWING BETTER SNOW GROWTH WITH A THICKER SNOW GROTH
AREA WITHIN THE DGZ. RUC SOUNDINGS SHOW INVERSION HEIGHTS BETWEEN
4KFT AND 5KFT THIS AFETERNOON WHICH IS ALSO VERIFIED BY THE MQT VAD
WIND PROFILE THIS AFETERNOON. THIS HAS ALLOWED GOOD SNOWFLAKE SIZE
THIS AFTERNOON RESULTING IN A QUICK INCH OR TWO OF FLUFFY SNOW ON A
NORTH TO NORTHWESTERLY WIND. DRY AIR REMAINS JUST TO THE NORTH OF
THE AREA THIS AFTERNOON...HOWEVER...THIS IS EXPECTED TO SHIFT
FARTHER SOUTH AROUND 00Z/01 AS INVERSION HEIGHTS BEGIN TO FALL TO
AROUND 3KFT. THIS SHOULD HELP TO REDUCE SNOWFALL RATES THIS EVENING
INTO THE OVERNIGHT HOURS.
AS THE SURFACE RIDGE EXPANDS TO THE NORTH OF LAKE SUPERIOR EXPECT
WINDS TO SHIFT TO THE NORTH AND NORTHEAST SHIFTING THE SNOWBANDS TO
THE NORTH TO NORTHEAST WIND FAVORED SNOW BELTS. AGAIN...REDUCED
MOISTURE...LOWERED INVERSION HEIGHTS ALONG WITH ANTICYCLONIC FLOW
WILL HELP TO KEEP SNOWFALL TOTALS IN CHECK ACROSS THE U.P. WITH UP
TO 2 INCHES EXPECTED ALONG THE NORTH TO NORTHEAST WIND FAVORED SNOW
BELTS. AS THE SURFACE RIDGE CENTER SHIFTS INTO THE NORTHERN PLAINS
ON SUNDAY EXPECT WINDS TO SHIFT TO A MORE NORTHERLY DIRECTION.
TEMPERATURES ALOFT WILL REMAIN COLD ENOUGH AND LOW LEVEL MOISTURE
OFF LAKE SUPERIOR WILL KEEP LAKE EFFECT SNOW IN NORTHERLY WIND
FAVORED LOCATIONS...WITH AROUND AN INCH ACCUMULATION EXPECTED IN
THESE AREAS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM EST SAT JAN 31 2015
...NW FLOW LES AND POOR VSBY DUE TO BLSN/DRSN MAY LEAD TO HEADLINES
WEDNESDAY INTO THURSDAY...
COLD WEEK IN STORE AS A BUILDING RIDGE ALOFT OVER WESTERN NORTH
AMERICA RESULTS IN MEAN TROUGHING CENTERED OVER HUDSON BAY EXTENDING
OVER GREAT LAKES AND NORTHEAST CONUS. PATTERN DOES NOT HOLD MUCH
OPPORTUNITY FOR WIDESPREAD SNOW. BEST CHANCE OF THAT MAY ACTUALLY
COME FRIDAY. OTHERWISE...LAKE EFFECT SNOW AND BLOWING/DRIFTING SNOW
WITH POOR VISIBILITY WILL BE MAIN ISSUE. APPEARED THAT MODERATION IN
THE CHILL WOULD START TO DEVELOP BY NEXT WEEKEND...BUT RECENT RUNS OF
THE ECMWF/GFS HAVE TRENDED TOWARD MORE TROUGHING AND COLDER
TEMPERATURES. WILL HAVE TO WAIT AND SEE IF THIS IS A LASTING TREND.
HIGH IMPACT WEATHER THAT JUSTIFIES ANY TYPE OF HEADLINES THROUGH THE
EXTENDED LIKELY WILL BE TIED TO THE LAKE EFFECT SNOW AND POOR VSBY.
BEST CHANCE OF SEEING HEADLINES WILL BE WEDNESDAY INTO THURSDAY FOR
NW FLOW AREAS NEAR LK SUPERIOR. WILL ALSO GIVE AN HONORABLE MENTION
FOR WSW FLOW ON TIP OF KEWEENAW PENINSULA LATE MONDAY INTO MONDAY
NIGHT...AS THOUGH THIS IS A VERY LOW PROBABILITY EVENT IT COULD NEED
A HEADLINE IF IT OCCURS. SUPPOSE THERE ALSO COULD BE NEED FOR WIND
CHILL ADVYS MONDAY MORNING AND AGAIN THURSDAY MORNING...BUT ATTM IT
DOES NOT LOOK LIKE A SURE THING THANKS TO LIGHT WINDS AND/OR MORE IN
TERMS OF LAKE MODERATION ON TEMPS.
NO REAL HAZARDOUS WEATHER EXPECTED SUNDAY NIGHT INTO MONDAY MORNING
WITH DIMINISHING WINDS AND WEAK LES AS INVERSIONS ARE WELL BLO 5KFT.
PLENTY COLD WITH TEMPS AT INVERION TOP BLO -20C. SLR/S ON THE
HIGHER/FLUFFY SIDE SO A COUPLE OF INCHES OF SNOW IS POSSIBLE FOR
MAINLY NCNTRL UPR MICHIGAN. GIVEN THE WEAKENING WINDS...MESOLOW
FORMATION REMAINS POSSIBLE WHICH WOULD ENHANCE CONVERGENCE AND ADD
TO THE SNOW AMOUNTS. HIGHEST PROBABILITY OF THIS OCCURRING WOULD BE
BTWN MARQUETTE AND PICTURED ROCKS LAKESHORE...SO LOOKING AT AU TRAIN
AND MUNISING AREAS. AWAY FM THE LES...TEMPS FALL WELL BLO ZERO LATE
SUNDAY NIGHT INTO MONDAY MORNING...BUT WITH LIGHT WINDS AND SOME
LAKE MODERATION/LAKE EFFECT CLOUDS...WIND CHILLS WILL MAINLY STAY
HIGHER THAN 20 BLO. SFC TROUGH CROSSING THE AREA MONDAY MORNING
SHOULD RESULT IN WINDS BECOMING MORE WESTERLY WHICH WILL DISRUPT THE
LES OVER ALGER COUNTY BUT WILL INCREASE IT ON THE KEWEENAW PENINSULA.
WESTERLY CONVERGENT FLOW LES HAS POTENTIAL TO DROP SEVERAL INCHES OF
SNOW LATE MONDAY AFTN INTO MONDAY NIGHT OVER NORTHERN SECTIONS OF
THE KEWEENAW. SOUNDINGS SHOW INVERSION AT LEAST TO 5KFT AND
DISTURBANCE ROTATING THROUGH AHEAD OF ANOTHER TROUGH MOVING OVER
UPPER GREAT LAKES ON TUESDAY MORNING. NAM SHARPER WITH TROUGH AND
BACKS WINDS ENOUGH TO KEEP HEAVIER LES OFFSHORE OF KEWEENAW. GFS AND
ECMWF NOT AS BACKED WITH WINDS. WILL CONTINUE TO SHOW HIGHEST POPS
ON THE KEWEENAW AND MENTION IN HAZARDOUS WEATHER OUTLOOK.
TROUGH SINKS OVER NORTHERN UPR MICHIGAN THROUGH DAY ON TUESDAY...
SPREADING THE LES TO NW FLOW SNOW BELTS OF NORTHERN UPR MICHGAN...
ESPECIALLY BY TUESDAY NIGHT. SOUNDINGS SHOW INVERSIONS UP TO 6-8 KFT
IN WAKE OF THE TROUGH WITH AS H85 TEMPS DROP TO -25C BY DAYBREAK ON
WEDNESDAY. SETUP WILL THEN FAVOR A PUSH OF HEAVIER LES AS THE MAIN
COLD FRONT MOVES THROUGH TUESDAY NIGHT INTO WEDNESDAY MORNING WITH
CONDITIONS QUICKLY TRANSITIONING TO SMALL SNOWFLAKE/LOW VSBY LES
REGIME FOR THE NORTHWEST WIND SNOW BELTS WEDNESDAY AFTN INTO
WEDNESDAY NIGHT. BLYR WINDS INCREASE THROUGH WEDNESDAY TO 25-30 KTS
SO BLSN AND DRSN WILL ALSO BECOME A CONCERN IN OPEN AREAS NEAR LK
SUPERIOR AND ESPECIALLY WHERE ICE IS BUILT UP ALONG THE SHORELINE.
AWAY FM THE LES THE MAIN THEME WILL BE COLD. TEMPS ON WEDNESDAY WILL
ONLY STRUGGLE INTO THE SINGLE DIGITS ABOVE ZERO WITH WIND CHILL
READINGS 10 TO 20 BLO ZERO. AS TEMPS FALL OFF WELL BLO ZERO ON
WEDNESDAY NIGHT OVER WESTERN UPR MICHIGAN...MAY SEE WIND CHILL
READINGS MAY COME CLOSE TO ADVY INTO THURSDAY MORNING. WINDS WILL BE
SLACKENING BY THIS TIME THOUGH...ESPECIALLY OVER INTERIOR SECTIONS
OF CWA. A BIT OF MODERATION ON THURSDAY FOR HIGHS WITH READINGS
NEARING 10 DEGREES OR REACHING THE LOWER TEENS. BLYR WINDS BACK SW
LATER THURSDAY INTO THURSDAY NIGHT AS HIGH PRESSURE RIDGE SETTLES FM
THE MIDDLE MISSISSIPPI RIVER VALLEY TO THE OHIO VALLEY. EXPECT THE
LES TO SHIFT OFFSHORE BY THURSDAY NIGHT. SINCE UPPER LAKES WILL BE
AHEAD OF ANOTHER SFC TROUGH CROSSING SOUTH CENTRAL CANADA...EXPECT
CLOUDS TO BE ON THE INCREASE WITH EVEN A POSSIBILITY OF LGT SNOW OR
FLURRIES. THUS...TEMPS SHOULD NOT CRASH TOO MUCH ON THURSDAY NIGHT.
STRONGER COLD FRONT WITH ANOTHER PUSH OF COLDER AIR EXPECTED TO
ARRIVE FRIDAY NIGHT INTO SATURDAY. SHORTWAVE/CONVERGENCE ALONG THE
SFC-H85 FRONT AND UPPER DIVERGENCE ON NOSE OF H3 JET STREAK COMBINE
TO SPREAD SWATH OF SNOW OVER MOST OF UPR MICHIGAN FRIDAY AFTN INTO
FRIDAY EVENING. TIMING MAY SHIFT AROUND SOME THOUGH CONSIDERING THIS
SOLUTION IN THE MODELS IS NEWER DEVELOPMENT. LOW CHANCE POPS WILL
WORK FOR NOW WITH THE SNOW ALONG THE COLD FRONT AND THEN MORE LOW
CHANCE POPS FOR NEXT SATURDAY WITH DEVELOPING NE FLOW LES IN WAKE OF
THE FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1155 PM EST SAT JAN 31 2015
MVFR CONDITIONS WILL CONTINUE FOR ALL SITES THIS FORECAST PERIOD
WITH NORTHEAST UPSLOPE WINDS. SNOW SHOWERS WILL BE PERIODIC AT SAW
AND CMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EST SAT JAN 31 2015
A COLD FRONT THAT SHIFTED SOUTH AND EAST OF THE AREA THIS AFTERNOON
ALONG WITH A DECENT PRESSURE GRADIENT ON THE BACK SIDE WILL ALLOW A
FEW GUSTS TO REACH 35KTS THIS AFTERNOON AND EVENING. MUCH LIGHTER
WINDS WILL PREVAIL SUNDAY AS HIGH PRESSURE DRIFTS ACROSS THE UPPER
GREAT LAKES REGION. LOW PRESSURE AND ASSOCIATED COLD FRONT WILL
APPROACH THE AREA MONDAY NIGHT AND THEN SWEEP THROUGH THE AREA
TUESDA NIGHT AND WEDNESDAY. ON THE BACK SIDE OF THIS SYSTEM...WINDS
WILL INCREASE FROM THE NORTHWEST WEDNESDAY AFTERNOON THROUGH
THURSDAY...WITH GALE FORCE GUSTS TO 35 KNOTS POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 5 AM EST SUNDAY FOR LSZ264-
266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KEC
LONG TERM...JLA
AVIATION...07
MARINE...KEC
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1153 AM CST Sun Feb 1 2015
...18Z Aviation Update...
.UPDATE...
Issued at 1030 AM CST SUN FEB 1 2015
The cold front has entered western Missouri during the past hour.
Low pressure currently located over the area is strengthening and
there is a widespread area of increasing pressure rises across
Kansas. This intensification will result in windy conditions
behind the advancing cold front, with frequent gusts to 35 mph.
Continuing to see light rainfall develop overhead at this time,
coincident with the surface low and associated cold front. This
area of light rain will eventually shift to the northeast. Will
continue to watch precipitation wrap around the back side of this
maturing storm system. The past several runs of the HRRR support
recent model output with bringing an area of flurries into the
region beginning mid/late afternoon across northern portions of
the area and spreading southeast deeper into the Missouri Ozarks
this evening. Brief loss of cloud ice will need to be monitored,
which would result in a brief period of drizzle/freezing drizzle
depending upon surface temperatures. However, deeper cold air
should quickly surge into the region and flurries should dominate
this evening. Cannot rule out a minor dusting of grassy surfaces
in some spots tonight, but overall, little if any accumulation is
expected.
&&
.SHORT TERM...(Today and Tonight)
It was a rainy night over extreme southeast Kansas and the
Missouri Ozarks. Temperatures were in the 30s, while winds were
breezy and generally from the south.
Nearly 100 percent coverage of measurable rain occurred this
morning as a large shield of precipitation was detected on radar
over the entire state of Missouri. More rain is expected this
morning, followed by a change over to flurries or light snow late
this morning and afternoon.
The forecast looks right on track as nearly all locations will not
experience any measurable snow accumulations. We can not rule out
a dusting to a half inch up north of Highway 54. Warm ground
temperatures, diurnal snowfall, and light rates will make
accumulating snow difficult.
A cold front will bring a colder air mass through southern Missouri
today, allowing for that change over to snow. Temperatures are
expected to drop throughout the day, while winds shift to the
northwest behind the front.
Lingering flurries or light snow are possible this evening,
particularly over central Missouri. Eventually this precipitation
will exit the area by early Monday morning. Overnight lows tonight
will drop into the teens.
.LONG TERM...(Monday through Saturday)
Zonal flow will quickly evolve Monday and Tuesday, allowing for a
brief warm up. We could observe temperatures warming into the 50s
by Tuesday afternoon. Both Monday and Tuesday will remain dry.
Our next cold front will arrive on Wednesday, forcing a band of
snow to impact the region behind it. We think this east to west
oriented band of snow will progress through the area quickly,
leaving behind some very minor accumulations. Air temperatures
will certainly be cold enough for snow to stick to the ground, and
we could see amounts ranging from zero up to two inches Wednesday
night into Thursday morning. We`re still four to five days out, so
this forecast could adjust in the future.
Beyond Thursday, it appears as though a strong upper level ridge
of high pressure will build into the nation`s mid section by
Friday, and persist through the weekend. This will set up a
beautiful upcoming weekend, with temperatures possibly warming
into the 50s and 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1145 AM CST SUN FEB 1 2015
Flight conditions will initially bounce around between MVFR and
IFR this afternoon, with both vis and cigs riding the line between
categories. Conditions should then improve to MVFR by evening, and
remain there overnight. A brief period of light snow/flurries is
possible at SGF late tonight, though at this time it doesn`t
appear that significant impacts will result.
In addition to cig/vis challenges, gusty west to northwest winds
will remain a concern through evening. Expect gusts to around 30
KT this afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Gagan
SHORT TERM...Cramer
LONG TERM...Cramer
AVIATION...Boxell
AREA FORECAST DISCUSSION...UPDATED
NWS SPRINGFIELD MO
1030 AM CST Sun Feb 1 2015
.UPDATE...
Issued at 1030 AM CST SUN FEB 1 2015
The cold front has entered western Missouri during the past hour.
Low pressure currently located over the area is strengthening and
there is a widespread area of increasing pressure rises across
Kansas. This intensification will result in windy conditions
behind the advancing cold front, with frequent gusts to 35 mph.
Continuing to see light rainfall develop overhead at this time,
coincident with the surface low and associated cold front. This
area of light rain will eventually shift to the northeast. Will
continue to watch precipitation wrap around the back side of this
maturing storm system. The past several runs of the HRRR support
recent model output with bringing an area of flurries into the
region beginning mid/late afternoon across northern portions of
the area and spreading southeast deeper into the Missouri Ozarks
this evening. Brief loss of cloud ice will need to be monitored,
which would result in a brief period of drizzle/freezing drizzle
depending upon surface temperatures. However, deeper cold air
should quickly surge into the region and flurries should dominate
this evening. Cannot rule out a minor dusting of grassy surfaces
in some spots tonight, but overall, little if any accumulation is
expected.
&&
.SHORT TERM...(Today and Tonight)
It was a rainy night over extreme southeast Kansas and the
Missouri Ozarks. Temperatures were in the 30s, while winds were
breezy and generally from the south.
Nearly 100 percent coverage of measurable rain occurred this
morning as a large shield of precipitation was detected on radar
over the entire state of Missouri. More rain is expected this
morning, followed by a change over to flurries or light snow late
this morning and afternoon.
The forecast looks right on track as nearly all locations will not
experience any measurable snow accumulations. We can not rule out
a dusting to a half inch up north of Highway 54. Warm ground
temperatures, diurnal snowfall, and light rates will make
accumulating snow difficult.
A cold front will bring a colder air mass through southern Missouri
today, allowing for that change over to snow. Temperatures are
expected to drop throughout the day, while winds shift to the
northwest behind the front.
Lingering flurries or light snow are possible this evening,
particularly over central Missouri. Eventually this precipitation
will exit the area by early Monday morning. Overnight lows tonight
will drop into the teens.
.LONG TERM...(Monday through Saturday)
Zonal flow will quickly evolve Monday and Tuesday, allowing for a
brief warm up. We could observe temperatures warming into the 50s
by Tuesday afternoon. Both Monday and Tuesday will remain dry.
Our next cold front will arrive on Wednesday, forcing a band of
snow to impact the region behind it. We think this east to west
oriented band of snow will progress through the area quickly,
leaving behind some very minor accumulations. Air temperatures
will certainly be cold enough for snow to stick to the ground, and
we could see amounts ranging from zero up to two inches Wednesday
night into Thursday morning. We`re still four to five days out, so
this forecast could adjust in the future.
Beyond Thursday, it appears as though a strong upper level ridge
of high pressure will build into the nation`s mid section by
Friday, and persist through the weekend. This will set up a
beautiful upcoming weekend, with temperatures possibly warming
into the 50s and 60s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 549 AM CST SUN FEB 1 2015
For the KSGF/KJLN/KBBG tafs: Low pressure and a cold front over
eastern KS will move quickly east through the taf sites over the
next few hours. Gusty winds will occur behind the front, especially at
KJLN and KSGF. IFR ceilings are common over the area, but progged
soundings and ensemble guidance indicate improving ceilings toward
18z with mvfr ceilings expected thereafter. Light rain/drizzle
should also diminish behind the front. Very light snow may briefly
occur as precipitation tapers off after 16z as colder air moves
in.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Gagan
SHORT TERM...Cramer
LONG TERM...Cramer
AVIATION...DSA
AREA FORECAST DISCUSSION
NWS BILLINGS MT
854 PM MST MON FEB 2 2015
.UPDATE...
NOT MUCH CHANGE TO THE GOING FORECAST THIS EVENING. MANY AREAS HAD
REACHED THEIR FORECAST MIN TEMPERATURES SO HAVE LOWERED
TEMPERATURES. EXPECT TEMPERATURES TO RISE FOR A FEW HOURS
LATER TONIGHT AS LOW PRESSURE MOVES ALONG A WARM FRONT SITUATED NW
TO SE OVER THE CENTRAL PART OF THE FORECAST AREA. THE LOW WILL
PUSH SE OF THE AREA BY 12Z BRINGING THE FRONT BACK S AS A COLD
FRONT. GUSTY GAP FLOW WINDS HAVE CONTINUED IN THE KLVM AREA THIS
EVENING DUE TO THE PROXIMITY OF THE SURFACE LOW AND FALLING
PRESSURES MOVING SE THROUGH THE AREA. THE WINDS HAVE REMAINED
BELOW ADVISORY CRITERIA. TWEAKED THE 03-06Z PERIOD TO ADD ANOTHER
PERIOD OF NEAR ADVISORY WINDS...OTHERWISE THE WINDS WILL ABATE AS
THE SURFACE LOW MOVES SE.
DESPITE ALL THE RADAR RETURNS N OF THE AREA...IT APPEARED THAT
PRECIPITATION WAS NOT REACHING THE GROUND BASED ON SURFACE
OBSERVATIONS SHOWING JUST MID CLOUD. HOWEVER PRECIPITATION WAS
OCCURRING W OF THE DIVIDE AND OVER THE BEARTOOTHS/ABSAROKAS AS A
JET NOSED INTO THE AREA AND OROGRAPHIC EFFECTS AIDED LIFT. MODELS
WERE IN AGREEMENT IN SPREADING PRECIPITATION INTO THE NORTHERN AND
EASTERN ZONES MAINLY AFTER 06Z AS A BAND OF FRONTOGENESIS WORKED
INTO THE AREA ALONG THE ADVANCING COLD FRONT. PRECIPITATION TYPE
WAS A CONCERN IN THESE AREAS DUE TO COLD SURFACE TEMPERATURES AND
TEMPERATURES ALOFT CLIMBING ABOVE ZERO DEGREES C. THE
SREF/SSEO/HRRR CONSENSUS WAS THAT SPOTTY FREEZING RAIN WAS
POSSIBLE WITH SNOW AND SLEET. RAP SOUNDINGS FOR KMLS SHOWED A
SLEET/FREEZING RAIN POSSIBILITY. MODELS ALSO AGREED THAT QPF
AMOUNTS WOULD BE LESS THAN /.10/ INCH SO ANY FREEZING
PRECIPITATION SHOULD BE LIGHT. THUS WILL NOT ISSUE ANY HIGHLIGHTS.
POPS WERE IN GOOD SHAPE.
GLANCING AT THE NEW MODELS FOR TUE AND TUE NIGHT SHOWED THAT QPF
AMOUNTS ON TUE REMAINED LIGHT ALONG THE ADVANCING COLD FRONT.
MODEL QPF THEN FOCUSED ON THE FOOTHILLS AND ADJACENT AREAS FOR 00Z
TO 06Z...BEFORE PRECIPITATION BEGAN SHIFTING S OUT OF THE AREA BY
12Z WED. FOLLOWING SHIFTS MAY BE ABLE TO MOVE THE PRECIPITATION
OUT OF THE AREA FASTER THAN WHAT IS IN THE CURRENT FORECAST.
ARTHUR
&&
.SHORT TERM...VALID FOR TUE AND WED...
OUR ATTENTION REMAINS ON SNOWFALL POTENTIAL TUESDAY NIGHT...THOUGH
SOUTHEAST MT WILL LIKELY GET SOME LIGHT SNOW TONIGHT AND TUESDAY.
A SHALLOW COLD FRONT IS DRAPED ACROSS THE AREA THIS AFTERNOON AND
THAT HAS HELD EAST WINDS IN BILLINGS AND KEPT HIGHS COLDER THAN WE
ANTICIPATED. SURFACE PRESSURE FALLS HAVE INCREASED ACROSS CENTRAL
MT THE LAST FEW HOURS WHICH REFLECTS ANOTHER APPROACHING SHORTWAVE
TROUGH. WARM AIR ADVECTION AHEAD OF THAT WAVE WILL PUSH THE FRONT
BACK NORTHEAST AND COULD PRODUCE SOME LIGHT PRECIPITATION. WE DID
INCLUDE A SLIGHT CHANCE OF FREEZING RAIN FROM ROUNDUP TO HYSHAM...
FORSYTH...COLSTRIP...MILES CITY...LAME DEER AND BROADUS TONIGHT
ALONG WITH THE CHANCE OF SNOW BASED ON A MODEST /BUT INCREASING/
PROBABILITY OF THAT IN PRECIPITATION-TYPE ALGORITHM OUTPUT FROM
RECENT SREF RUNS. HOWEVER...IT IS VERY POSSIBLE THAT THE WARM
LAYER ALOFT WILL NOT GET QUITE TO THE +3 C LEVEL NEEDED FOR FULL
MELTING ABOVE THE GROUND...WHICH IS ACTUALLY REFLECTED BY THE FACT
THAT THE 12 UTC SSEO GUIDANCE CALLS FOR ICE PELLETS/PARTIALLY
FROZEN SNOW INSTEAD OF FREEZING RAIN. OTHERWISE WE EXPECT SOME
LIGHT SNOWFALL TUESDAY IN PORTIONS OF SOUTHEASTERN MT...BUT THE
STRONGER /ALBEIT STILL WEAK/ FORCING LOOKS TO STAY MAINLY IN
NORTHEASTERN MT AND WESTERN ND.
BY TUESDAY EVENING...A MORE DYNAMIC PROCESS IS EXPECTED WHEN A
120 KT 300-MB JET STREAK DIVES INTO IDAHO AND CAUSES THE ARCTIC
COLD FRONT TO SURGE SOUTHWARD ACROSS THE REGION. QG-FORCING TIED
TO THAT JET STREAK AND POTENTIALLY AIDED BY THE RIGHT-ENTRANCE
REGION OF ANOTHER JET TO OUR NORTHEAST IS FORECAST BY THE MODELS
TO BE QUICK-HITTING...BUT STRONG...AND FOCUSED ALONG AND SOUTH OF
A LINE FROM LIVINGSTON TO BILLINGS AND SHERIDAN. WE MAINLY STAYED
THE COURSE WITH THE PRIOR SNOW FORECAST TUESDAY NIGHT...BUT MULTI-
MODEL CONSENSUS QPF NUMBERS HAVE SLOWLY DROPPED DURING THE LAST 24
HOURS AND FORECAST SOUNDINGS FROM THE 12 UTC GFS AND NAM AREN/T AS
SUPPORTIVE OF SNOW-TO-LIQUID RATIOS OVER 20 TO 1 AS THEY WERE THIS
TIME YESTERDAY. THUS...WE HAVE SLIGHTLY LOWERED SNOWFALL TOTALS IN
PLACES AWAY FROM THE FOOTHILLS...BUT NOT ENOUGH FOR A FUNDAMENTAL
CHANGE IN THE FINAL FORECAST. SLIPPERY ROADS ARE LIKELY A GIVEN...
AND THIS COULD BE A HEADLINE-WORTHY SNOW EVENT IN PLACES LIKE RED
LODGE. IT/S LESS CLEAR WHETHER OR NOT BILLINGS WILL GET A PLOWABLE
/2 INCH/ SNOWFALL THOUGH...WHICH IS A QUESTION MARK REFLECTED BY A
LARGE...MULTI-MODEL ENSEMBLE RUN BY WPC THAT SUPPORTS OUR FORECAST
70 PERCENT PROBABILITY FOR 1 INCH OF SNOW IN THE CITY...BUT ONLY A
40 TO 50 PERCENT PROBABILITY OF GETTING 2 INCHES. THERE ARE SUBTLE
DIFFERENCES IN THE 12 UTC GFS AND ECMWF MODEL CAMPS TOO THAT COULD
STILL MAKE SNOW TOTALS EITHER LIGHTER OR HEAVIER...NAMELY WHETHER
OR NOT A COUPLED JET STRUCTURE CAN DEVELOP. IT IS FOR THAT REASON
THE FORECAST WAS ONLY NUDGED SLIGHTLY TOWARD THE CONSENSUS OF A
BIT LOWER SNOW TOTALS TODAY.
REGARDLESS OF HOW MUCH SNOW FALLS TUESDAY NIGHT...IT LOOKS LIKE WE
WILL DRY OUT WEDNESDAY...BUT THE AMOUNT OF SNOW COVER WILL PLAY A
ROLE IN HOW MUCH TEMPERATURES CAN RISE ON THAT DAY. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
FAST ZONAL FLOW REGIME WILL DOMINATE THE WEATHER PATTERN OVER THE
NORTHERN ROCKIES DURING THE EXTENDED PERIOD. PLENTY OF MID LEVEL
MOISTURE WILL BE ENTRAINED IN THIS FLOW ALONG WITH PERIODIC
DISTURBANCES. THIS WILL KEEP PERIODS OF SNOW GOING IN THE
MOUNTAINS MAINLY ON WEST FACING SLOPES...BUT DOWNSLOPE WINDS LEE
OF THE DIVIDE WILL MAINTAIN ONLY SLIGHT PRECIPITATION CHANCES FOR
THE MOST PART ACROSS THE PLAINS. THIS DOWNSLOPE INFLUENCE WILL
ALSO EXTEND TO TEMPERATURES PUSHING HIGHS INTO THE 50S AND 60S..FOR
ANOTHER STRETCH OF WELL ABOVE NORMAL TEMPERATURES. IT DOES LOOK
LIKE A PATTERN CHANGE DEVELOPS HEADING INTO TUESDAY THAT COULD
BRING A BETTER CHANCE AT PRECIPITATION AND COLDER
TEMPERATURES...BUT THIS IS STILL A LONG WAYS OUT WITH PLENTY OF
TIME TO CHANGE. COULD BE SOME PRETTY WINDY PERIODS DURING THE
EXTENDED PERIOD BUT WITH TEMPERATURES GETTING INTO THE 50S AND 60S
THE THREAT FOR STRONG GAP FLOW WINDS LOOKS TO BE SIGNIFICANTLY
REDUCED FOR THE WESTERN FOOTHILLS. CHAMBERS
&&
.AVIATION...
LOW LEVEL WIND SHEAR IS EXPECTED IN THE FIRST 2-3 THOUSAND FEET
TONIGHT INTO EARLY TUESDAY MORNING MOST PLACES WITH WINDS
INCREASING FROM THE NORTHWEST UP TO 35KTS. A FEW SNOW
SHOWERS...POSSIBLY MIXED WITH A LITTLE FREEZING RAIN...WILL SWING
OVER LOCATIONS EAST OF KBIL TONIGHT. THESE EASTERN AREAS WILL HAVE
LOCAL MVFR TO IFR CONDITIONS. MOUNTAINS WILL BE OBSCURED AS SNOW
SHOWERS INVADE THERE. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 029/038 009/031 025/051 037/060 041/060 038/055 035/054
13/O 72/J 10/B 01/N 11/N 11/N 11/B
LVM 035/047 016/037 031/055 038/061 044/059 038/058 034/050
22/R 73/J 22/W 11/N 23/W 11/N 22/W
HDN 025/033 006/029 013/050 030/056 038/057 032/055 030/053
24/O 72/J 10/B 01/B 11/N 11/B 11/B
MLS 015/023 903/023 014/045 027/053 037/056 032/054 031/052
56/S 41/B 01/B 01/B 12/W 11/B 11/B
4BQ 019/033 003/027 017/050 030/059 040/058 034/055 034/057
24/O 51/B 00/B 01/B 12/W 11/B 11/B
BHK 007/022 907/018 009/044 026/048 033/049 032/049 030/051
66/S 20/B 00/B 11/B 12/W 11/B 11/B
SHR 031/041 013/029 018/050 029/061 035/058 029/054 029/051
12/R 73/J 10/B 00/B 11/B 11/B 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1139 AM CST SUN FEB 1 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
MAIN FORECAST CONCERN IS ADDITIONAL SNOW ACCUMULATION THIS MORNING
AND NEAR-BLIZZARD CONDITIONS EXPECTED LATE THIS MORNING AND MUCH
OF THE AFTERNOON.
LATEST RADAR SCANS SHOWS THAT THE SNOW IS BEGINNING TO WANE
OVERALL. SOME EMBEDDED STRONGER SNOW BANDS ARE PRESENT NEAR
SCHUYLER/NORTH BEND WITH ANOTHER ENHANCED AREA DRIFTING NORTHEAST
TO THE OMAHA/CB METRO AREA. METARS ARE SHOWING VISIBILITIES
GENERALLY 1 TO 2 MILES. WE DID HEAR OF ONE REPORT OF THUNDER...BUT
NEVER DID SEE THAT SHOW UP IN THE LIGHTNING DETECTION NET. THUS
FAR SNOW AMOUNTS HAVE BEEN AVERAGING 4 TO 9 INCHES IN THE WINTER
STORM WARNING AREA. MANY AREAS PROBABLY WON`T ACHIEVE THE WINTER
STORM CRITERIA AMOUNT OF 8 INCHES. BUT...WE FEEL THE WINTER STORM
WARNING REMAINS JUSTIFIED DUE TO THE EXTREMELY POOR ROAD
CONDITIONS BEING REPORTED AND THE EXPECTED NEAR-BLIZZARD
CONDITIONS POSSIBLE TODAY WHEN THE WINDS KICK IN. FOR THE
REMAINDER OF THIS MORNING...MOISTURE PROFILES REMAIN DEEP AND
STILL WELL LOCATED WITHIN THE DENDRITIC GROWTH ZONE. THUS SNOW
PRODUCTION REMAINS GOOD...THOUGH OVERALL SYSTEM LIFT IS PULLING
OUT TO THE NORTHEAST. FOR NOW THROUGH THIS AFTERNOON ANOTHER 1 TO
3 INCHES APPEARS LIKELY ACROSS THE COUNTY WARNING AREA WITH THE
HIGHEST AMOUNTS FOCUSED ACROSS EAST-CENTRAL NEBRASKA AND WESTERN
IOWA.
AS OF 9Z WINDS HAVE ALREADY PICKED UP AT OFK/LCG/ONL AND EXPECT
ALL AREAS TO BE VERY WINDY BY LATE THIS MORNING. RUC SOUNDINGS
SUGGEST DECENT MIXING MAY OCCUR THIS AFTERNOON AND WIND GUSTS OVER
40 MPH AREN`T OUT OF THE QUESTION. NOT SURE IF THE STRONGEST WINDS
WILL BE SUSTAINED LONG ENOUGH ALONG WITH LOW VISIBILITIES TO
NECESSITATE A BLIZZARD WARNING. CONDITIONS WILL SURELY BE VERY
POOR...THUS WE ADDED NEAR-BLIZZARD WORDING TO THE LATEST WINTER
STORM WARNING UPDATE. THE SNOW SHOULD BE FINISHED JUST AFTER
SUNSET THIS EVENING AND WINDS WILL STEADILY DECREASE OVERNIGHT AS
WEAK SURFACE HIGH PRESSURE SETTLES IN OVER THE AREA. DECIDED TO
LOWER OVERNIGHT LOWS A FEW DEGREES GIVEN SIGNIFICANT SNOW COVER IN
PLACE.
LOOKS LIKE DRY WEATHER FOR MONDAY AND MONDAY NIGHT. BY TUESDAY A
WEAK CLIPPER SYSTEM TRACKS ACROSS NORTHEAST NEBRASKA AND NORTHWEST
IOWA. SOME LIGHT SNOW MAY OCCUR...OPTED FOR LOW CHANCES FOR NOW.
AS THIS FEATURE MOVES EAST IT STRENGTHENS AND OUR FAR NORTHEASTERN
COUNTIES COULD PICK UP A COUPLE INCHES OF SNOW DURING THE DAY ON
TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
NORTHWEST FLOW ALOFT WILL CONTINUE THROUGH THE END OF THE WEEK
BEFORE A MORE ZONAL FLOW PATTERN SETS UP BY SATURDAY. ONE
SIGNIFICANT SHORTWAVE ROLLING THROUGH THE FLOW WILL BRING ANOTHER
CHANCE FOR SNOW TUESDAY NIGHT AND WEDNESDAY WITH COLDER HIGH
PRESSURE SETTLING INTO THE PLAINS FOLLOWING SHORTWAVE. TIMING AND
TRACK OF SNOW WITH THIS SHORTWAVE IS STILL IN QUESTION...BUT MODELS
SEEM TO BE COMING TOGETHER SOMEWHAT IN SHOWING MUCH OF EASTERN
NEBRASKA AND SOUTHWEST IOWA GETTING LIGHT SNOW AT SOME POINT TUESDAY
NIGHT OR WEDNESDAY. AMOUNTS SHOULD REMAIN IN THE INCH OR TWO RANGE
GIVEN LOWER MOISTURE CONTENT AND PROGRESSIVE MOVEMENT. LOWS TUESDAY
NIGHT IN THE TEENS WILL ONLY GAIN A FEW DEGREES INTO THE 20S
WEDNESDAY GIVEN CLOUDS/PRECIP AND A SWITCH TO NORTHERLY WINDS.
COLDER AIR SETTLING SOUTH BEHIND SHORTWAVE WILL GIVE US A COLD START
THURSDAY MORNING WITH LOWS IN THE SINGLE DIGITS...WITH SOME SUB-ZERO
READINGS LIKELY.
A QUICK REBOUND STILL LOOKS ON TRACK THURSDAY WITH WINDS BECOMING
SOUTHERLY...WHICH CONTINUE FRIDAY AND SATURDAY. THUS A SLIGHT
WARMING TREND IS FORECAST...CLIMBING FROM THE 20S THURSDAY TO THE
30S AND PERHAPS LOWER 40S FRIDAY AND SATURDAY.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1131 AM CST SUN FEB 1 2015
LIFR TO IFR CONDITIONS WILL CONTINUE AT THE TAF SITES THIS
AFTERNOON AS STRONG NORTHWEST WINDS GUSTING TO 35 KTS COMBINED
WITH FALLING AND BLOWING SNOW REDUCE VISIBILITIES TO A HALF MILE
OR LESS. WINDS WILL BEGIN TO DIMINISH AND SNOW WILL TAPER OFF FROM
WEST TO EAST LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS.
AFTER 03-06Z...CONDITIONS SHOULD BEGIN TO SLOWLY IMPROVE WITH VFR
CONDITIONS EXPECTED AT ALL SITES BY 09Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011-
016-017-030-031-090>093.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR NEZ012-015-
018-032>034-042>045-050>053-065>068-078-088-089.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ043-055-
056-069-080-091.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ079-090.
&&
$$
SHORT TERM...PEARSON
LONG TERM...DERGAN
AVIATION...KERN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
526 AM CST SUN FEB 1 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
MAIN FORECAST CONCERN IS ADDITIONAL SNOW ACCUMULATION THIS MORNING
AND NEAR-BLIZZARD CONDITIONS EXPECTED LATE THIS MORNING AND MUCH
OF THE AFTERNOON.
LATEST RADAR SCANS SHOWS THAT THE SNOW IS BEGINNING TO WANE
OVERALL. SOME EMBEDDED STRONGER SNOW BANDS ARE PRESENT NEAR
SCHUYLER/NORTH BEND WITH ANOTHER ENHANCED AREA DRIFTING NORTHEAST
TO THE OMAHA/CB METRO AREA. METARS ARE SHOWING VISIBILITIES
GENERALLY 1 TO 2 MILES. WE DID HEAR OF ONE REPORT OF THUNDER...BUT
NEVER DID SEE THAT SHOW UP IN THE LIGHTNING DETECTION NET. THUS
FAR SNOW AMOUNTS HAVE BEEN AVERAGING 4 TO 9 INCHES IN THE WINTER
STORM WARNING AREA. MANY AREAS PROBABLY WON`T ACHIEVE THE WINTER
STORM CRITERIA AMOUNT OF 8 INCHES. BUT...WE FEEL THE WINTER STORM
WARNING REMAINS JUSTIFIED DUE TO THE EXTREMELY POOR ROAD
CONDITIONS BEING REPORTED AND THE EXPECTED NEAR-BLIZZARD
CONDITIONS POSSIBLE TODAY WHEN THE WINDS KICK IN. FOR THE
REMAINDER OF THIS MORNING...MOISTURE PROFILES REMAIN DEEP AND
STILL WELL LOCATED WITHIN THE DENDRITIC GROWTH ZONE. THUS SNOW
PRODUCTION REMAINS GOOD...THOUGH OVERALL SYSTEM LIFT IS PULLING
OUT TO THE NORTHEAST. FOR NOW THROUGH THIS AFTERNOON ANOTHER 1 TO
3 INCHES APPEARS LIKELY ACROSS THE COUNTY WARNING AREA WITH THE
HIGHEST AMOUNTS FOCUSED ACROSS EAST-CENTRAL NEBRASKA AND WESTERN
IOWA.
AS OF 9Z WINDS HAVE ALREADY PICKED UP AT OFK/LCG/ONL AND EXPECT
ALL AREAS TO BE VERY WINDY BY LATE THIS MORNING. RUC SOUNDINGS
SUGGEST DECENT MIXING MAY OCCUR THIS AFTERNOON AND WIND GUSTS OVER
40 MPH AREN`T OUT OF THE QUESTION. NOT SURE IF THE STRONGEST WINDS
WILL BE SUSTAINED LONG ENOUGH ALONG WITH LOW VISIBILITIES TO
NECESSITATE A BLIZZARD WARNING. CONDITIONS WILL SURELY BE VERY
POOR...THUS WE ADDED NEAR-BLIZZARD WORDING TO THE LATEST WINTER
STORM WARNING UPDATE. THE SNOW SHOULD BE FINISHED JUST AFTER
SUNSET THIS EVENING AND WINDS WILL STEADILY DECREASE OVERNIGHT AS
WEAK SURFACE HIGH PRESSURE SETTLES IN OVER THE AREA. DECIDED TO
LOWER OVERNIGHT LOWS A FEW DEGREES GIVEN SIGNIFICANT SNOW COVER IN
PLACE.
LOOKS LIKE DRY WEATHER FOR MONDAY AND MONDAY NIGHT. BY TUESDAY A
WEAK CLIPPER SYSTEM TRACKS ACROSS NORTHEAST NEBRASKA AND NORTHWEST
IOWA. SOME LIGHT SNOW MAY OCCUR...OPTED FOR LOW CHANCES FOR NOW.
AS THIS FEATURE MOVES EAST IT STRENGTHENS AND OUR FAR NORTHEASTERN
COUNTIES COULD PICK UP A COUPLE INCHES OF SNOW DURING THE DAY ON
TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
NORTHWEST FLOW ALOFT WILL CONTINUE THROUGH THE END OF THE WEEK
BEFORE A MORE ZONAL FLOW PATTERN SETS UP BY SATURDAY. ONE
SIGNIFICANT SHORTWAVE ROLLING THROUGH THE FLOW WILL BRING ANOTHER
CHANCE FOR SNOW TUESDAY NIGHT AND WEDNESDAY WITH COLDER HIGH
PRESSURE SETTLING INTO THE PLAINS FOLLOWING SHORTWAVE. TIMING AND
TRACK OF SNOW WITH THIS SHORTWAVE IS STILL IN QUESTION...BUT MODELS
SEEM TO BE COMING TOGETHER SOMEWHAT IN SHOWING MUCH OF EASTERN
NEBRASKA AND SOUTHWEST IOWA GETTING LIGHT SNOW AT SOME POINT TUESDAY
NIGHT OR WEDNESDAY. AMOUNTS SHOULD REMAIN IN THE INCH OR TWO RANGE
GIVEN LOWER MOISTURE CONTENT AND PROGRESSIVE MOVEMENT. LOWS TUESDAY
NIGHT IN THE TEENS WILL ONLY GAIN A FEW DEGREES INTO THE 20S
WEDNESDAY GIVEN CLOUDS/PRECIP AND A SWITCH TO NORTHERLY WINDS.
COLDER AIR SETTLING SOUTH BEHIND SHORTWAVE WILL GIVE US A COLD START
THURSDAY MORNING WITH LOWS IN THE SINGLE DIGITS...WITH SOME SUB-ZERO
READINGS LIKELY.
A QUICK REBOUND STILL LOOKS ON TRACK THURSDAY WITH WINDS BECOMING
SOUTHERLY...WHICH CONTINUE FRIDAY AND SATURDAY. THUS A SLIGHT
WARMING TREND IS FORECAST...CLIMBING FROM THE 20S THURSDAY TO THE
30S AND PERHAPS LOWER 40S FRIDAY AND SATURDAY.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 523 AM CST SUN FEB 1 2015
IFR TO LIFR CIGS/VSBYS IN SNOW AND BLOWING SNOW ARE EXPECTED
THROUGH THIS AFTERNOON. SNOWFALL WILL GRADUALLY DECREASE THROUGH
THE DAY...BUT NORTH WINDS GUSTING TO 35KT WILL CREATE OCCASIONAL
VSBYS AT OR BELOW 1SM. WINDS SHOULD DECREASE INTO THE 15 TO 25KT
RANGE BETWEEN 22Z AND 02Z...THEN DECREASE TO LESS THAN 10KT BY
06Z. CIGS SHOULD IMPROVE TO MVFR BY 00Z...THEN SCATTER OUT BEFORE
06Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011-
016-017-030-031-090>093.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR NEZ012-015-
018-032>034-042>045-050>053-065>068-078-088-089.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ043-055-
056-069-080-091.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ079-090.
&&
$$
SHORT TERM...PEARSON
LONG TERM...DERGAN
AVIATION...DERGAN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
345 AM CST SUN FEB 1 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
MAIN FORECAST CONCERN IS ADDITIONAL SNOW ACCUMULATION THIS MORNING
AND NEAR-BLIZZARD CONDITIONS EXPECTED LATE THIS MORNING AND MUCH
OF THE AFTERNOON.
LATEST RADAR SCANS SHOWS THAT THE SNOW IS BEGINNING TO WANE
OVERALL. SOME EMBEDDED STRONGER SNOW BANDS ARE PRESENT NEAR
SCHUYLER/NORTH BEND WITH ANOTHER EHANCED AREA DRIFTING NORTHEAST
TO THE OMAHA/CB METRO AREA. METARS ARE SHOWING VISIBILITIES
GENERALLY 1 TO 2 MILES. WE DID HEAR OF ONE REPORT OF THUNDER...BUT
NEVER DID SEE THAT SHOW UP IN THE LIGHTNING DETECTION NET. THUS
FAR SNOW AMOUNTS HAVE BEEN AVERAGING 4 TO 9 INCHES IN THE WINTER
STORM WARNING AREA. MANY AREAS PROBABLY WON`T ACHIEVE THE WINTER
STORM CRITERIA AMOUNT OF 8 INCHES. BUT...WE FEEL THE WINTER STORM
WARNING REMAINS JUSTIFIED DUE TO THE EXTREMELY POOR ROAD
CONDITIONS BEING REPORTED AND THE EXPECTED NEAR-BLIZZARD
CONDITIONS POSSIBLE TODAY WHEN THE WINDS KICK IN. FOR THE
REMAINDER OF THIS MORNING...MOISTURE PROFILES REMAIN DEEP AND
STILL WELL LOCATED WITHIN THE DENDRITIC GROWTH ZONE. THUS SNOW
PRODUCTION REMAINS GOOD...THOUGH OVERALL SYSTEM LIFT IS PULLING
OUT TO THE NORTHEAST. FOR NOW THROUGH THIS AFTERNOON ANOTHER 1 TO
3 INCHES APPEARS LIKELY ACROSS THE COUNTY WARNING AREA WITH THE
HIGHEST AMOUNTS FOCUSED ACROSS EAST-CENTRAL NEBRASKA AND WESTERN
IOWA.
AS OF 9Z WINDS HAVE ALREADY PICKED UP AT OFK/LCG/ONL AND EXPECT
ALL AREAS TO BE VERY WINDY BY LATE THIS MORNING. RUC SOUNDINGS
SUGGEST DECENT MIXING MAY OCCUR THIS AFTERNOON AND WIND GUSTS OVER
40 MPH AREN`T OUT OF THE QUESTION. NOT SURE IF THE STRONGEST WINDS
WILL BE SUSTAINED LONG ENOUGH ALONG WITH LOW VISIBILITIES TO
NECESSITATE A BLIZZARD WARNING. CONDITIONS WILL SURELY BE VERY
POOR...THUS WE ADDED NEAR-BLIZZARD WORDING TO THE LATEST WINTER
STORM WARNING UPDATE. THE SNOW SHOULD BE FINISHED JUST AFTER
SUNSET THIS EVENING AND WINDS WILL STEADILY DECREASE OVERNIGHT AS
WEAK SURFACE HIGH PRESSURE SETTLES IN OVER THE AREA. DECIDED TO
LOWER OVERNIGHT LOWS A FEW DEGREES GIVEN SIGNIFICANT SNOW COVER IN
PLACE.
LOOKS LIKE DRY WEATHER FOR MONDAY AND MONDAY NIGHT. BY TUESDAY A
WEAK CLIPPER SYSTEM TRACKS ACROSS NORTHEAST NEBRASKA AND NORTHWEST
IOWA. SOME LIGHT SNOW MAY OCCUR...OPTED FOR LOW CHANCES FOR NOW.
AS THIS FEATURE MOVES EAST IT STRENGTHENS AND OUR FAR NORTHEASTERN
COUNTIES COULD PICK UP A COUPLE INCHES OF SNOW DURING THE DAY ON
TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 221 AM CST SUN FEB 1 2015
NORTHWEST FLOW ALOFT WILL CONTINUE THROUGH THE END OF THE WEEK
BEFORE A MORE ZONAL FLOW PATTERN SETS UP BY SATURDAY. ONE
SIGNIFICANT SHORTWAVE ROLLING THROUGH THE FLOW WILL BRING ANOTHER
CHANCE FOR SNOW TUESDAY NIGHT AND WEDNESDAY WITH COLDER HIGH
PRESSURE SETTLING INTO THE PLAINS FOLLOWING SHORTWAVE. TIMING AND
TRACK OF SNOW WITH THIS SHORTWAVE IS STILL IN QUESTION...BUT MODELS
SEEM TO BE COMING TOGETHER SOMEWHAT IN SHOWING MUCH OF EASTERN
NEBRASKA AND SOUTHWEST IOWA GETTING LIGHT SNOW AT SOME POINT TUESDAY
NIGHT OR WEDNESDAY. AMOUNTS SHOULD REMAIN IN THE INCH OR TWO RANGE
GIVEN LOWER MOISTURE CONTENT AND PROGRESSIVE MOVEMENT. LOWS TUESDAY
NIGHT IN THE TEENS WILL ONLY GAIN A FEW DEGREES INTO THE 20S
WEDNESDAY GIVEN CLOUDS/PRECIP AND A SWITCH TO NORTHERLY WINDS.
COLDER AIR SETTLING SOUTH BEHIND SHORTWAVE WILL GIVE US A COLD START
THURSDAY MORNING WITH LOWS IN THE SINGLE DIGITS...WITH SOME SUB-ZERO
READINGS LIKELY.
A QUICK REBOUND STILL LOOKS ON TRACK THURSDAY WITH WINDS BECOMING
SOUTHERLY...WHICH CONTINUE FRIDAY AND SATURDAY. THUS A SLIGHT
WARMING TREND IS FORECAST...CLIMBING FROM THE 20S THURSDAY TO THE
30S AND PERHAPS LOWER 40S FRIDAY AND SATURDAY.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 518 PM CST SAT JAN 31 2015
WINTER EVENT WILL IMPACT THE TAF SITES THROUGH MOST OF THE PERIOD.
IFR AND OCCASIONALLY LIFR CONDITIONS WITH SNOW AT ALL TAF SITES
WITH VISIBILITIES RANGING FROM 1/2 TO 1 1/2 MILES MOSTLY. WINDS
REMAIN LIGHT FROM THE EAST OR SOUTHEAST INITIALLY. WINDS WILL
CONTINUE TO BACK BECOMING NORTHEAST...THEN NORTH AND SUBSTANTIALLY
INCREASING BY 11-13Z TO 22 TO 35 KNOTS. AT THAT TIME...SNOW AND
BLOWING SNOW WILL CONTINUE TO REDUCE VISIBILITY THROUGH MUCH OF
THE DAY SUNDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011-
016-017-030-031-090>093.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR NEZ012-015-
018-032>034-042>045-050>053-065>068-078-088-089.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ043-055-
056-069-080-091.
WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ079-090.
&&
$$
SHORT TERM...PEARSON
LONG TERM...DERGAN
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1034 PM CST SAT JAN 31 2015
.UPDATE...
ISSUED AT 1029 PM CST SAT JAN 31 2015
AFTER COORDINATION WITH SURROUNDING WFOS AND GETTING A COUPLE OF
NEW SNOWFALL REPORTS OF 4 TO 5 INCHES IN THE FAIRBURY...WILBER AND
LINCOLN AREAS...OPTED TO EXPAND THE WINTER STORM WARNING. SNOWFALL
RATES HAVE DEFINITELY PICKED UP IN THE I80 CORRIDOR WHICH WILL
HELP BRING TOTALS UP JUST SLIGHTLY MORE. HEAVY SNOW WILL BE
COMPACTING...BUT IT`S STILL ACCUMULATING AND WILL PUSH US CLOSER
TO THE 8 INCH CRITERIA IN A FEW AREAS. ALSO...WITH THE INCREASING
WINDS...FELT MORE COMFORTABLE GETTING A HEADLINE UPGRADE OUT
DURING THE EVENING NEWS RATHER THAN WAITING UNTIL THE OVERNIGHT
HOURS.
UPDATE ISSUED AT 920 PM CST SAT JAN 31 2015
WINTER HAS RETURNED. AS EXPECTED...00Z SUBJECTIVE UPPER AIR
ANALYSIS REVEALED A SIGNIFICANT AMOUNT OF MOISTURE WITH PW VALUES
ABOUT 210-280% ABOVE NORMAL. 500MB HEIGHT FALLS RANGED FROM 40 TO
80 METERS ACROSS THE REGION...AND OVERALL THE AREA REMAINS WITHIN
THE ENTRANCE REGION OF A BROAD UPPER LEVEL JET STREAK TO OUR
NORTH.
SNOW CONTINUES AT THIS TIME...AND WILL DO SO THROUGH MOST OF
SUNDAY...ALTHOUGH THE INTENSITY WILL BE WINDING DOWN ON SUNDAY.
THE SNOW SO FAR HAS BEEN A VERY HEAVY WET SNOW WITH SNOWFALL
RATIOS WELL BELOW 10:1. TEMPS HAVE REMAINED JUST ABOVE FREEZING IN
MOST AREAS THIS EVENING...WHICH IS LIKELY CONTRIBUTING TO ROAD
CONDITIONS BECOMING HAZARDOUS...PERHAPS MORESO THAN EXPECTED.
WHILE WINDS REMAIN LIGHT CURRENTLY LESS THAN 10 KNOTS IN MOST
AREAS...THEY ARE BACKING AND BEGINNING TO INCREASE IN NORTHEAST
NEBRASKA AS LOW PRESSURE BEGINS TO MOVE THROUGH CENTRAL KANSAS.
WINDS WILL SUBSTANTIALLY INCREASE BY 12Z AS THE LOW PRESSURE
CENTER MOVES ACROSS THE KC AREA...WHICH WILL THEN CREATE AREAS OF
BLOWING SNOW.
REGARDING SNOWFALL AMOUNTS...WE CURRENTLY HAVE 5 TO 9 INCHES
FORECAST WITH HIGH END WINTER WEATHER ADVISORIES AND WARNINGS IN
EFFECT AND THAT TREND SEEMS OK. THE HEAVY WET SNOW IS COMPACTING
QUITE A BIT ON THE GROUND. HAVE UPPED AMOUNTS JUST SLIGHTLY BASED
ON REPORTS. THUS...THIS WILL LIKELY END UP ON THE HIGH END OF THE
ADVISORY CATEGORY. HAVE ALSO CONSIDERED UPGRADING TO A WINTER
STORM WARNING TO ACCOUNT FOR THE BLOWING SNOW THAT WILL BE TAKING
PLACE ON SUNDAY...WITH GUSTS EASILY APPROACHING 40 MPH. WILL HAVE
TO SEE HOW VISIBILITIES RESPOND TO THAT AS IT MAY END UP IN NEAR
BLIZZARD CONDITIONS IN OUTLYING REMOTE AREAS ACROSS EASTERN
NEBRASKA. WILL DEFER THAT TO THE NEXT FORECAST ONCE WE GET MORE
MODEL DATA IN.
AS A SIDE NOTE...WE WILL BREAK WATER EQUIVALENT RECORDS AT BOTH
LINCOLN AND OMAHA FOR JAN 31.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CST SAT JAN 31 2015
SNOW AND HEADLINES ARE THE MAIN PROBLEMS IN THE SHORT TERM AND HAVE
KEPT PRIMARY FOCUS IN THE NEXT 24-30 HOURS.
A 90 KNOT JET MAX WAS ON THE FRONT SIDE OF THE TROUGH ACROSS THE
SOUTHWEST US AT 12Z. ANOTHER AREA OF STRONG WINDS AT 300 MB WAS FROM
NORTHERN MINNESOTA INTO THE OHIO VALLEY. LATEST WATER VAPOR IMAGERY
AND RECENT RAP MODEL INITIALIZATIONS SHOW A CLOSED LOW DROPPING
SOUTHWARD ACROSS BAJA. A MID LEVEL TROUGH WAS LOCATED FROM WESTERN
NEBRASKA INTO EASTERN COLORADO AND ANOTHER WAVE WAS DROPPING
SOUTHEAST FROM MONTANA. A 12 HOUR 500 MB HEIGHT FALL MAX OF ABOUT
130 METERS WAS OVER MONTANA AND ANOTHER AROUND 100 METERS WAS NEAR
THE MEXICO/NEW MEXICO BORDER. SO THIS IS A FAIRLY COMPLEX SETUP...
WITH SOME PHASING OF THE NORTHERN AND SOUTHERN STREAMS EXPECTED
TONIGHT.
MOISTURE HAS BEEN RETURNING OVER THE CENTRAL PLAINS WITH AREAS OF
SNOW OR A MIX OF RAIN AND SNOW. WILL MAKE SOME MINOR CHANGES TO
HEADLINES...ADDING A FEW COUNTIES TO THE WARNING IN THE NORTH.
IMPRESSIVE MOISTURE (850-700 MB SPECIFIC HUMIDITY VALUES 3-4 G/KG
AT 6 PM THIS EVENING...FALLING TO 2-3 G/KG BY 12Z SUNDAY) ALONG
WITH GOOD FORCING SHOULD ALLOW FOR SNOW AMOUNTS FROM ABOUT 4 TO 9
INCHES IN MOST OF THE FORECAST AREA. HIGHEST SNOW AMOUNTS EXPECTED
NORTH AND EAST. AS COLDER AIR SINKS IN FROM THE NORTH BEHIND THE
COLD FRONT (WHICH EXTENDED FROM WISCONSIN BACK INTO SOUTHWEST
NEBRASKA EARLY THIS AFTERNOON)...TEMPERATURES WILL FALL AND ROADS
WILL START TO ICE UP/BECOME SNOW COVERED AND SLICK. TEMPERATURES
SHOULD START SLIDING TONIGHT AND CONTINUE TO DROP THROUGH MUCH OF
THE DAY SUNDAY. STRONG NORTH SURFACE WINDS WILL LIKELY ALSO CAUSE
SOME BLOWING SNOW LATER TONIGHT AND AT LEAST THROUGH EARLY SUNDAY
AFTERNOON.
HEADLINES WILL CONTINUE UNTIL 6 PM SUNDAY IN NEBRASKA AND UNTIL 9 PM
SUNDAY IN SOUTHWEST IOWA. IT IS POSSIBLE THESE MAY BE CANCELLED
EARLIER THAN THAT...BUT THAT IS WHAT WE WILL GO WITH FOR NOW.
SNOW AMOUNTS WILL DECREASE THROUGH THE DAY AS DRIER AIR MOVES IN
FROM THE WEST AND LIFT PULLS OUT OF THE REGION. HIGH PRESSURE AT
THE SURFACE BUILDS IN FOR SUNDAY NIGHT. WINDS WILL DECREASE AND
WITH CLEARING SKIES HAVE LOWS FALLING OR AROUND ZERO...OR EVEN
BELOW ZERO IN OUR NORTHERN COUNTIES. WARM AIR ADVECTION AND SOUTH
WINDS SHOULD INCREASE MONDAY. KEPT A SMALL CHANCE OF SNOW NORTH
AND NORTHEAST OF OMAHA...BUT NOT A BIG DEAL. A SLIGHTLY BETTER
CHANCE OF SNOW ARRIVES FOR TUESDAY. 12Z GFS SEEMED A BIT TOO HIGH
ON QPF TUESDAY...BUT WILL SEE HOW THINGS TREND NEXT FEW MODEL
RUNS.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 325 PM CST SAT JAN 31 2015
LOOK FOR MODERATING TEMPERATURES THIS PERIOD. FAST WEST/NORTHWEST
MID LEVEL FLOW WILL OCCUR EARLY...WITH A RIDGE DEVELOPING OVER THE
WESTERN US. THIS RIDGE SHOULD BUILD EAST THROUGH THE WEEK. HIGHS
WILL BE 20S WEDNESDAY AND THURSDAY RISING TO ABOVE NORMAL FOR
FRIDAY AND SATURDAY. THERE IS SOME CHANCE OF LIGHT SNOW WEDNESDAY
OTHERWISE IT SHOULD BE MAINLY DRY.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 518 PM CST SAT JAN 31 2015
WINTER EVENT WILL IMPACT THE TAF SITES THROUGH MOST OF THE PERIOD.
IFR AND OCCASIONALLY LIFR CONDITIONS WITH SNOW AT ALL TAF SITES
WITH VISIBILITIES RANGING FROM 1/2 TO 1 1/2 MILES MOSTLY. WINDS
REMAIN LIGHT FROM THE EAST OR SOUTHEAST INITIALLY. WINDS WILL
CONTINUE TO BACK BECOMING NORTHEAST...THEN NORTH AND SUBSTANTIALLY
INCREASING BY 11-13Z TO 22 TO 35 KNOTS. AT THAT TIME...SNOW AND
BLOWING SNOW WILL CONTINUE TO REDUCE VISIBILITY THROUGH MUCH OF
THE DAY SUNDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ011-016-017-
030-031-090>093.
WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR NEZ012-015-018-
032>034-042>045-050>053-065>068-078-088-089.
IA...WINTER STORM WARNING UNTIL 9 PM CST SUNDAY FOR IAZ043-055-056-
069-080-091.
WINTER STORM WARNING UNTIL 6 PM CST SUNDAY FOR IAZ079-090.
&&
$$
UPDATE...DEWALD
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
951 PM CST MON FEB 2 2015
.UPDATE...
ISSUED AT 951 PM CST MON FEB 2 2015
THE INCOMING 00 UTC DETERMINISTIC SUITE AND LATEST RADAR TRENDS
THROUGH 0345 UTC CONTINUE TO AFFIRM THE ONGOING FORECAST OF
WIDESPREAD LIGHT SNOWFALL ACCUMULATIONS ACROSS MUCH OF WESTERN AND
CENTRAL NORTH DAKOTA TONIGHT INTO TUESDAY. MINIMAL CHANGES
REQUIRED TO INCORPORATE OBSERVED TRENDS THROUGH 0330 UTC.
UPDATE ISSUED AT 633 PM CST MON FEB 2 2015
NO SIGNIFICANT CHANGES REQUIRED OTHER THAN TO BLEND TO OBSERVED
TRENDS THROUGH 00 UTC. WIDESPREAD 1 TO 2 INCHES OF SNOW FOR
WESTERN AND MUCH OF CENTRAL NORTH DAKOTA REMAINS ON TRACK FOR LATE
TONIGHT INTO TUESDAY...SUPPORTED BY THE 18 UTC GUIDANCE SUITE AND
20-22 UTC HRRR ITERATIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
THIS AFTERNOON...WEAK HIGH PRESSURE OVER THE REGION WILL ALLOW FOR
MAINLY PARTLY TO MOSTLY SUNNY SKIES. THEN TONIGHT ANOTHER WEAK
CLIPPER SYSTEM WILL MOVE ACROSS NORTH DAKOTA AND EXIT THE REGION
TUESDAY. MOISTURE CHARACTERISTICS ARE SIMILAR TO PAST FEW SYSTEMS
AND THE RESULT SHOULD BE SIMILAR WITH 1 TO 2 INCH SNOW TOTALS WITH
PERHAPS AN ISOLATED 3 INCH TOTAL. THE BAND OF SNOW SHOULD SPREAD
NORTHWEST TO SOUTHEAST ACROSS THE REGION. WINDS WILL NOT BE
SIGNIFICANT WITH THIS SYSTEM. WITH ADVANCING CLOUDS THIS EVENING DO
NOT EXPECT SIGNIFICANT TEMPERATURE FALLS TONIGHT. LOWS -3 NORTH
CENTRAL TO 15 ABOVE FAR SOUTHWEST. TUESDAY WILL SEE HIGHS AROUND 10
NORTH CENTRAL TO 28 SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
AN ACTIVE PATTERN WILL HIGHLIGHT THE LONG TERM.
THE 12Z DETERMINISTIC MODELS PROVIDE GOOD AGREEMENT ON THE OVERALL
UPPER LEVEL PATTERN REMAINING NORTHWEST ALOFT THROUGH MUCH OF THE
EXTENDED. THIS PATTERN RESULTS IN SEVERAL SHORT WAVES AND
FREQUENT CHANCES FOR PRECIPITATION...FRIDAY THROUGH MONDAY. MUCH
OF THE PRECIPITATION IS EXPECTED TO BE SNOW...ALTHOUGH PERIODS OF
RAIN/FREEZING RAIN/WINTRY MIX ARE POSSIBLE. PREDICTABILITY OF
SHORTWAVES EMBEDDED IN THE FAST NORTHWEST FLOW IS LOW...SO TIMING
AND EXACT LOCATIONS WILL CHANGE WITH FUTURE FORECAST.
A GENERAL WARMING TREND WITH ABOVE AVERAGE TEMPERATURES FOR MUCH OF
NORTH DAKOTA WILL COMMENCE THURSDAY. THE 12Z ENSEMBLES AGREE ON WARM
AIR ADVECTION MOVING INTO THE STATE FROM THE SOUTHWEST...AS A RIGID
OVER THE PACIFIC PROPAGATES EASTWARD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY)
ISSUED AT 950 PM CST MON FEB 2 2015
WIDESPREAD IFR CONDITIONS IN SNOW DEVELOPING ACROSS WESTERN AND
CENTRAL NORTH DAKOTA LATE TONIGHT INTO TUESDAY MORNING...IMPROVING
TO MVFR THROUGH TUESDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...AC
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
634 PM CST MON FEB 2 2015
.UPDATE...
ISSUED AT 633 PM CST MON FEB 2 2015
NO SIGNIFICANT CHANGES REQUIRED OTHER THAN TO BLEND TO OBSERVED
TRENDS THROUGH 00 UTC. WIDESPREAD 1 TO 2 INCHES OF SNOW FOR
WESTERN AND MUCH OF CENTRAL NORTH DAKOTA REMAINS ON TRACK FOR LATE
TONIGHT INTO TUESDAY...SUPPORTED BY THE 18 UTC GUIDANCE SUITE AND
20-22 UTC HRRR ITERATIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
THIS AFTERNOON...WEAK HIGH PRESSURE OVER THE REGION WILL ALLOW FOR
MAINLY PARTLY TO MOSTLY SUNNY SKIES. THEN TONIGHT ANOTHER WEAK
CLIPPER SYSTEM WILL MOVE ACROSS NORTH DAKOTA AND EXIT THE REGION
TUESDAY. MOISTURE CHARACTERISTICS ARE SIMILAR TO PAST FEW SYSTEMS
AND THE RESULT SHOULD BE SIMILAR WITH 1 TO 2 INCH SNOW TOTALS WITH
PERHAPS AN ISOLATED 3 INCH TOTAL. THE BAND OF SNOW SHOULD SPREAD
NORTHWEST TO SOUTHEAST ACROSS THE REGION. WINDS WILL NOT BE
SIGNIFICANT WITH THIS SYSTEM. WITH ADVANCING CLOUDS THIS EVENING DO
NOT EXPECT SIGNIFICANT TEMPERATURE FALLS TONIGHT. LOWS -3 NORTH
CENTRAL TO 15 ABOVE FAR SOUTHWEST. TUESDAY WILL SEE HIGHS AROUND 10
NORTH CENTRAL TO 28 SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
AN ACTIVE PATTERN WILL HIGHLIGHT THE LONG TERM.
THE 12Z DETERMINISTIC MODELS PROVIDE GOOD AGREEMENT ON THE OVERALL
UPPER LEVEL PATTERN REMAINING NORTHWEST ALOFT THROUGH MUCH OF THE
EXTENDED. THIS PATTERN RESULTS IN SEVERAL SHORT WAVES AND
FREQUENT CHANCES FOR PRECIPITATION...FRIDAY THROUGH MONDAY. MUCH
OF THE PRECIPITATION IS EXPECTED TO BE SNOW...ALTHOUGH PERIODS OF
RAIN/FREEZING RAIN/WINTRY MIX ARE POSSIBLE. PREDICTABILITY OF
SHORTWAVES EMBEDDED IN THE FAST NORTHWEST FLOW IS LOW...SO TIMING
AND EXACT LOCATIONS WILL CHANGE WITH FUTURE FORECAST.
A GENERAL WARMING TREND WITH ABOVE AVERAGE TEMPERATURES FOR MUCH OF
NORTH DAKOTA WILL COMMENCE THURSDAY. THE 12Z ENSEMBLES AGREE ON WARM
AIR ADVECTION MOVING INTO THE STATE FROM THE SOUTHWEST...AS A RIGID
OVER THE PACIFIC PROPAGATES EASTWARD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 634 PM CST MON FEB 2 2015
WIDESPREAD IFR CONDITIONS IN SNOW DEVELOPING ACROSS WESTERN AND
CENTRAL NORTH DAKOTA LATE TONIGHT INTO TUESDAY MORNING...IMPROVING
TO MVFR THROUGH TUESDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...AC
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 AM CST SUN FEB 1 2015
.UPDATE...
ISSUED AT 1241 AM CST SUN FEB 1 2015
QUICK UPDATE TO CAPTURE LATEST TRENDS.
SNOW CONTINUES TO DIMINISH ACROSS CENTRAL AND SOUTHERN NORTH
DAKOTA. ADDITIONAL ACCUMULATION OF ONE INCH OR LESS IS POSSIBLE
SOUTH OF I-94. SNOW SHOULD BE COMPLETELY OUT OF THE AREA BY
SUNRISE. WIND CHILL TEMPERATURES CONTINUE TO DROP INTO THE TEENS
AND 20S BELOW ZERO. ONLY OTHER MINOR CHANGE WAS TO SKY COVER.
CLEARED OUT THE CLOUDS FROM NORTH TO SOUTH A LITTLE SOONER THAN
PREVIOUSLY FORECAST.
UPDATE ISSUED AT 944 PM CST SAT JAN 31 2015
NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE OTHER THAN TO
BLEND TO OBSERVED TRENDS THROUGH 03 UTC AS THE FOCUS FOR SNOWFALL
WILL CONTINUE TO SHIFT INTO FAR SOUTH CENTRAL NORTH DAKOTA THROUGH
THE NIGHT. FRONTOGENESIS AND DENDRITIC OMEGA ARE DECREASING AS
EXPECTED...MARKING A SLOW DECLINE IN SNOWFALL INTENSITY.
UPDATE ISSUED AT 547 PM CST SAT JAN 31 2015
RADAR TRENDS THROUGH 2330 UTC ARE ALIGNED WELL WITH THE 20
THROUGH 22 UTC HRRR ITERATIONS...AND WILL WEIGH HEAVILY UPON THEIR
SOLUTIONS FOR THE REMAINDER OF THE NIGHT. EXPECT A BAND OF
MODERATE TO AT TIMES HEAVY SNOW TO CONTINUE TO DEVELOP FROM CENTER
THROUGH BISMARCK...NEW SALEM...FLASHER...CARSON AND MOTT THROUGH
03 UTC IN ASSOCIATION WITH STRENGTHENING 850-700 MB FRONTOGENESIS.
WHILE SNOW WILL CONTINUE THEREAFTER...PEAK INTENSITIES WILL BEGIN
TO SLOWLY DECREASE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 245 PM CST SAT JAN 31 2015
.SHORT TERM...TONIGHT AND SUNDAY...
MAIN ISSUED THIS FORECAST PERIOD WILL BE SNOW POTENTIAL THIS
AFTERNOON AND EVENING. SNOW IS STILL FORECAST TO REMAIN BELOW
ADVISORY CRITERIA WITH FAIRLY WIDESPREAD SNOW AMOUNTS OF 3 INCHES
ACROSS WEST CENTRAL ND THIS AFTERNOON WITH 2 TO 3 INCHES SPREADING
INTO THE SOUTH CENTRAL TONIGHT. AN ISOLATED 4 INCH AMOUNT IS
POSSIBLE BUT NOT WIDESPREAD. THEN WIND CHILLS BECOME A CONCERN
ACROSS THE NORTH CENTRAL THROUGH THE NORTHERN JAMES RIVER VALLEY
TONIGHT INTO SUNDAY MORNING. LATEST RADAR TRENDS SHOW THE SNOW THIS
AFTERNOON IS CONCENTRATED ACROSS THE WEST CENTRAL WHERE UP TO 3
INCHES MAY FALL BY EARLY EVENING. THEN THIS EVENING THEN SNOW WILL
BE FOCUSED ALONG AN H300 JET REGION WHICH EXTENDS NORTHEAST TO
SOUTHWEST ACROSS WESTERN NORTH DAKOTA. THE LATEST HRRR RUNS FOLLOW
THE JET DYNAMICS AND FORM A SNOW BAND THAT EXTENDS FROM SOUTHWEST
NORTH DAKOTA INTO THE SOUTH CENTRAL BETWEEN 00Z-06Z. BELIEVE THERE
WILL ANOTHER 3 INCH BAND OF SNOW FROM BOWMAN NORTHEAST TO BISMARCK.
THE MOST RAPIDLY CHANGING WEATHER WILL BE FOUND SOUTH CENTRAL WHERE
THE PARTLY SUNNY SKIES THIS AFTERNOON WILL QUICKLY CHANGE TO SNOW.
BUFKIT SOUNDINGS FROM DICKINSON TO BISMARCK THIS EVENING SHOW A
FAIRLY DEEP DENDRITIC GROWTH ZONE WITH SUPER SATURATION WITH RESPECT
TO ICE. THUS THERE WILL BE GOOD SNOW POTENTIAL FROM THE LIMITED QPF
THAT HAS BEEN CONSISTENTLY FORECAST FOR THIS SYSTEM.
THIS EVENING...WILL ISSUE A WIND CHILL ADVISORY FOR WIND CHILLS 25
TO 30 BELOW EXTENDING FROM BOTTINEAU COUNTY SOUTHEAST THROUGH
STUTSMAN COUNTY. TOWNS INCLUDED IN THIS AREA INCLUDE
BOTTINEAU...RUGBY... HARVEY AND JAMESTOWN.
BY SUNDAY MORNING THE SNOW WILL END. SHOULD SEE CONSIDERABLE
SUNSHINE BOT COLD TEMPERATURES SUNDAY
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM CST SAT JAN 31 2015
THE PATTERN REMAINS UNSETTLED FOR THE EARLY AND LATTER PORTIONS OF
THE LONG TERM PERIOD. SHORTWAVE TROUGHS CONTINUE TO CIRCULATE AROUND
THE HUDSON BAY LOW AND INTO NORTH DAKOTA. ALTHOUGH THERE APPEARS TO
BE A BREAK WEDNESDAY INTO EARLY FRIDAY...BOTH THE GFS AND ECMWF ARE
HINTING AT ANOTHER SYSTEM FRIDAY NIGHT THROUGH SATURDAY.
SUNDAY NIGHT AND MONDAY...NOT A LOT OF CHANGE FROM PREVIOUS RUNS AND
THOUGHTS AS THIS WILL BE A BRIEF/MINOR WARM AIR ADVECTION
PRECIPITATION EVENT MONDAY. SOUTHWEST WINDS SUNDAY NIGHT WILL QUICKLY
SHIFT TO THE NORTHWEST DURING THE MORNING IN THE WEST AND AFTERNOON
IN THE CENTRAL AS COLD AIR ADVECTION AGAIN TAKES CONTROL. PER
NAM/GFS BUFKIT SOUNDINGS...HAVE TEMPERED HIGHS IN THE SOUTHWEST AS
COLD AIR ADVECTION TAKES OVER BY MID TO LATE MORNING AND BASICALLY
PUTS A CAP ON RISING TEMPERATURES. SNOWFALL POTENTIAL REMAINS LIGHT
WITH AROUND A HALF INCH ALONG AND WEST OF THE MISSOURI RIVER.
FOR TUESDAY...IT APPEARS THE STRONGER BAROCLINIC ZONE ASSOCIATED
WITH AN ARCTIC INTRUSION REMAINS IN SOUTH CENTRAL MONTANA AND
WESTERN SOUTH DAKOTA. THE GFS HAS SHIFTED THE MAIN SNOW AXIS ACROSS
THE FAR SOUTHWEST. THE NAM/ECMWF ALSO INDICATE A WEAKER SCENARIO BUT
HAVE THIS AREA FARTHER EAST AS WELL. QPF TODAY VERSUS THE LAST FEW
RUNS HAVE LOWERED QUITE A BIT. SNOWFALL ACCUMULATIONS ARE NOW MORE
LIKELY TO RANGE FROM 1 TO 1.5 INCHES ACROSS WESTERN AND SOUTH
CENTRAL NORTH DAKOTA.
WEDNESDAY THROUGH SATURDAY...MAINLY DRY CONDITIONS CAN BE EXPECTED AS
NORTHWEST FLOW CONTINUES WEDNESDAY WITH ARCTIC AIR AND SURFACE HIGH
PRESSURE DOMINATING. HIGHS WILL RANGE FROM AROUND ZERO IN THE TURTLE
MOUNTAINS TO 20 DEGREES ABOVE ZERO IN THE SOUTHWEST. WARM AIR
ADVECTION ONCE AGAIN COMMENCES THURSDAY AND FRIDAY. AN ALBERTA
CLIPPER WITH A FAIRLY TIGHT BAROCLINIC ZONE IS FORECAST TO DEVELOP
ACROSS CENTRAL AND NORTHERN NORTH DAKOTA FRIDAY THROUGH SATURDAY.
THE ECMWF IS MUCH COLDER AS THE BAROCLINIC ZONE SAGS FURTHER SOUTH.
BOTH MODELS DEPICT DECENT PRECIPITATION DEVELOPING DURING THIS
PERIOD AND SNOW WOULD BE THE LIKELY CANDIDATE IN THE NORTH. THERE IS
A POTENTIAL FOR A WINTRY MIX IN/AROUND THE WARMER SIDE OF THE
BAROCLINIC ZONE. WILL NEED TO MONITOR THIS IN THE COMING DAYS. HIGH
TEMPERATURES FRIDAY/SATURDAY WILL DEPEND ON WHERE THE BAROCLINIC
ZONE SETS UP ACROSS SOUTHWEST/NORTHERN NORTH DAKOTA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1241 AM CST SUN FEB 1 2015
IFR CONDITIONS IN SNOW WILL CONTINUE AT KDIK AND KBIS THROUGH
ABOUT 07-09 UTC. OTHERWISE VFR CONDITIONS WILL PREVAIL AT ALL TAF
SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR NDZ004-005-
012-013-022-023-025-036-037.
&&
$$
UPDATE...AJ
SHORT TERM...WAA
LONG TERM...KS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
142 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE TRAVELING UP THE OHIO VALLEY WILL BRING WIDESPREAD
SNOW AND RAIN TONIGHT INTO MONDAY. MUCH COLDER AIR WILL ARRIVE MONDAY
NIGHT WITH HIGH PRESSURE MOVING IN FROM THE WEST. SNOW AND RAIN
WILL BE POSSIBLE WEDNESDAY WHEN A DISTURBANCE IS FORECAST TO CROSS
THE GREAT LAKES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE FIRST CONCERN FOR THE NEAR TERM OF THE FORECAST WAS TO ADD
SOME MORE SLEET. THIS IS BASED PARTLY ON SEVERAL REPORTS IN
SOUTHEASTERN INDIANA...BUT ALSO BASED ON THE WAY CONDITIONS HAVE
EVOLVED TONIGHT AS EVIDENCED BY OBSERVATIONS. DEWPOINT DEPRESSIONS
ARE STILL RATHER HIGH...WITH WET BULB TEMPERATURES BELOW ZERO. THE
KILN SOUNDING INDICATED QUITE A BIT OF DRY AIR BELOW 900MB...BUT
ALSO INDICATED THAT THE WARM LAYER IN THE LOWEST 2KM WAS SLIGHTLY
WARMER THAN THE CURRENT FORECAST HAD SUGGESTED WAS GOING TO
HAPPEN. WITH A SLIGHTLY WARMER STARTING POINT...THE ZONE OF MIXED
PRECIP AND ICE ACCUMULATIONS HAS BEEN SHIFTED SLIGHTLY NORTHWARD.
HOWEVER...THESE ACCUMULATIONS SHOULD STILL REMAIN FAIRLY
LIGHT. THE SOUTHERN TIER OF THE WINTER WEATHER ADVISORY WILL COVER
THE THREAT NICELY...AND IN FACT...THE FAR SOUTHERN COUNTIES IN THE
ADVISORY MAY NOT GET COLD ENOUGH TO SUPPORT MUCH OF A THREAT FOR
ANY GLAZE ACCUMULATION (PERHAPS JUST SOME SLEET MIXING IN NEAR THE
ONSET OF PRECIPITATION).
BASED ON A FULL ANALYSIS OF 18Z MODEL RUNS...RECENT RAP/HRRR
RUNS...AND THE 00Z NAM...ANOTHER SLIGHT ADJUSTMENT WAS MADE TO THE
OVERALL FORECAST ARRANGEMENT FOR SUNDAY. THERE ARE NO SIGNS AT ALL
OF A REVERSAL OF THE GRADUAL NORTHWARD (WARMER) TREND...AND THE
02Z RAP / 00Z NAM ARE PERHAPS AS FAR NORTH WITH THE WARM AIR AS
ANY MODEL HAS BEEN THROUGH THE FORECAST OF THIS EVENT. IT IS STILL
VERY CLEAR THAT ANY LOCATION THAT REMAINS PURELY SNOW WILL RECEIVE
A VERY LARGE AMOUNT (AROUND A FOOT)...BUT THE TRANSITION ZONE
SEEMS TO BE CREEPING NORTHWARD WITH EACH NEW MODEL CYCLE.
THUS...WHILE SNOW TOTALS IN THE FAR NORTHERN CWA (MERCER THROUGH
HARDIN) REMAIN AS HIGH AS BEFORE (UP TO 12 INCHES)...A MODEST
DOWNWARD ADJUSTMENT WAS MADE FURTHER SOUTH. THE NEW WSW PRODUCT
ACCOUNTS FOR THIS CHANGE WITH SOME REFINED AND SLIGHTLY LOWER
NUMBERS FOR SOME OF THE COUNTY SEGMENTS. HOWEVER...IT WOULD BE
PREFERRED TO SEE THE ENTIRE 00Z MODEL SUITE BEFORE MAKING A MORE
SUBSTANTIAL CHANGE (AS WOULD BE SUGGESTED BY THE LATEST MODELS).
PREVIOUS DISCUSSION >
SURFACE LOW PRESSURE WILL DEVELOP OVER THE GREAT PLAINS TONIGHT IN
RESPONSE TO A DIGGING 500 MB TROUGH OVER THE ROCKIES. WHILE JET
STREAM ENERGY INCREASES AS IT ROUNDS THE BASE OF THE UPPER
TROUGH...THE SURFACE LOW WILL DEEPEN...AND THE PRESSURE GRADIENT
WILL TIGHTEN...INCREASING MOISTURE ADVECTION TOWARD THE OHIO
VALLEY.
DURING THIS PROCESS...A BAND OF ISENTROPIC LIFT WILL SET UP OVER
THE ILN AREA WELL AHEAD OF THE SURFACE LOW TO THE WEST. LATEST
MODELS SHOW THE BAND AFFECTING LOCATIONS MAINLY NORTH OF
CINCINNATI. PRECIP WILL START AROUND MIDNIGHT...WITH TYPE VARYING
WITH RESPECT TO ATMOSPHERIC TEMPERATURE PROFILES. EXPECT DEFINITE SNOW
FOR THE NORTH HALF OF THE FA INCLUDING DAYTON...COLUMBUS AND
WAPAKONETA. FOR LOCATIONS ROUGHLY NEAR WILMINGTON...WARMER AIR
ALOFT SHOULD ALLOW A WINTRY MIX. FARTHER SOUTH FROM CINCINNATI TO
PORTSMOUTH AND ACROSS NORTHERN KENTUCKY...THERE WILL BE A CHANCE
FOR A LIGHT WINTRY MIX OF FZRA AND RA.
DUE TO THE SIGNIFICANT NATURE OF SNOW ACCUMULATIONS BASED ON
QPF AND MODEL SOUNDINGS...WENT WITH A WINTER STORM WARNING FOR
SNOW NORTH OF DAY AND CMH. FARTHER SOUTH WENT WITH A WINTER
WEATHER ADVISORIES FOR LIGHTER SNOW AND ICE ACCUMULATIONS. SEE
CLEWSWILN FOR FURTHER DETAILS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
SURFACE LOW WILL PROGRESS UP THE OHIO VALLEY TO SOUTHERN INDIANA ON
SUNDAY. WHILE SNOW PERSISTS NORTH OF DAYTON...CONTINUED MOISTURE
ADVECTION ALONG THE WARM CONVEYOR BELT AHEAD OF THE LOW WILL ALLOW
PRECIP TO OVERSPREAD THE AREA BY SUNDAY EVENING. WITH MODELS
PRESENTING A WARMER SOLUTION...RAIN IS THE ANTICIPATED PRECIP TYPE
SOUTH OF I-70...WITH SNOW NORTH. A BAND OF FRONTOGENETIC FORCING
WILL ENHANCE PRECIP ESPECIALLY ACROSS THE NORTH WHERE SIGNIFICANT
SNOW WILL ACCUMULATE.
THE SURFACE LOW WILL BE MOVING FROM EASTERN OHIO TO PENNSYLVANIA
BY MONDAY MORNING. PRECIP WILL TRANSITION TO ALL SNOW AREA WIDE
BEFORE DIMINISHING IN COLD ADVECTION BEHIND THE DEPARTING LOW.
SNOW IN THE NORTH WILL BE ENHANCED BY STRONG DEFORMATION IN THE NW
QUADRANT OF THE LOW. TOTAL SNOW AMOUNTS WILL VARY GREATLY...WITH
OVER 10 INCHES POSSIBLE OVER WEST CENTRAL OHIO...A FEW INCHES NEAR
DAYTON AND COLUMBUS...AND UNDER AN INCH AT CINCINNATI...PORTSMOUTH
AND NORTHERN KENTUCKY.
COLD TEMPERATURES AND WIND CHILLS ARE IN STORE FOR MONDAY AND
MONDAY NIGHT. HIGHS IN THE TEENS AN 20S MONDAY WILL BE FOLLOWED BY
LOWS RANGING FROM THE NEGATIVE SINGLE DIGITS NORTH TO THE MID
TEENS SOUTH MONDAY NIGHT. THE COLD TEMPS WILL COMBINE WITH BRISK
WINDS TO PRODUCE WIND CHILLS BELOW MINUS 10 OVER THE NORTH HALF OF
THE FA. WILL MENTION WIND CHILLS IN HWO FOR NOW...AND A WIND CHILL
ADVISORY MAY EVENTUALLY BE ISSUED ACROSS THE NORTH.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
NORTHWEST MID/UPPER LEVEL FLOW WITH THE CENTER OF SPRAWLING SURFACE
HIGH PRESSURE SLIDING OFF TO THE EAST COAST BY TUESDAY EVENING. THIS
HIGH WILL PROVIDE COLD AND DRY WEATHER CONDITIONS. AFTER A COLD
START TO THE DAY...TEMPERATURES WILL WARM TO HIGHS 5 TO 10 DEGREES
BELOW NORMAL. TUESDAYS HIGHS TO RANGE FROM THE MID 20S NE TO THE
UPPER 30S SW.
FLOW BACKS WESTERLY A HEAD OF DIGGING TROF OVER THE GREAT LAKES...
WITH A QUICK MORNING SYSTEM MOVING THRU THE REGION TUESDAY
NIGHT/WED. WILL HAVE CHANCE POPS FOR THIS PERIOD WITH THE BEST
CHANCE ACRS THE NORTH. PCPN WILL LKLY MIX WITH AND CHANGE TO RAIN
IN THE SOUTH PRIOR TO COLD FRONTAL PASSAGE WED AFTN. LOWS TUESDAY
NIGHT TO RANGE FROM THE LOWER 20S NE TO THE UPPER 20S SW. HIGHS ON
WED FROM THE LOWER 30S NORTH TO THE LOWER/MID 40S FAR SOUTH.
REINFORCING SHOT OF COLD AIR WITH HIGH PRESSURE OF CANADIAN ORIGIN
TO BUILD SE BECOMING CENTERED OVER OHIO THURSDAY. COLD AND DRY
WEATHER ON TAP WITH WED NIGHT/S LOWS FROM THE SINGLE DIGITS ACRS THE
NORTHWEST WHERE SNOW PACK WILL EXIST TO NEAR 20 SE. HIGHS ON THURSDAY
TO BE AROUND 15 DEGREES BELOW NORMAL...RANGING FROM THE UPPER TEENS
NW TO THE UPPER 20S SE.
THIS SFC HIGH BUILDS SLOWLY EAST TO THE EAST COAST BY THE END OF THE
WEEK. COLD TEMPERATURES TO CONTINUE WITH LOWS THURSDAY NIGHT FROM
THE SINGLE DIGITS BELOW ZERO NW TO NEAR 10 SE.
AS THE HIGH MOVES OFF TO THE EAST A RETURN FLOW DEVELOPS WITH SOME
SOME MODERATION TO TEMPERATURES INTO THE WEEKEND. HIGHS ON FRIDAY
FROM NEAR 20 NORTH TO THE LOWER 30S FAR SOUTH AND WARMING ON
SATURDAY FROM THE UPPER 20S NORTH TO AROUND 40 SOUTH. MODEL SOLN
SPREAD LARGE NEXT SATURDAY REGARDING TIMING AND PLACEMENT OF NEXT
SYSTEM. HAVE KEPT FCST DRY THRU SAT AFTN ATTM MORE LIKE THE GFS SOLN
BUT THIS MAY CHANGE WITH LATER UPDATES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A BAND OF SNOW AND MIXED PRECIPITATION IS LIFTING NORTH THROUGH
THE REGION AND WILL CONTINUE TO AFFECT NORTHERN TAF SITES KDAY AND
KCMH/LCK UNTIL ABOUT 9Z AT KDAY AND 12Z FOR KCMH/LCK. A DRY PUNCH
WILL PULL IN WARM AIR AND PRECIP SHOULD SHUT OFF FOR A MAJORITY
OF THE DAY TODAY AT MOST SITES...WITH KCMH/LCK HANGING ON TO THE
LOWER CIGS IN SHOWERS THROUGH EARLY MORNING.
IN THE AFTERNOON...TOWARDS 20Z...THE PREVAILING RAIN WILL RAPIDLY
OVERSPREAD THE REGION FROM THE WEST. THE LOW WILL TRACK NORTH OF
KCVG AFTER 0Z AND UNTIL THIS HAPPENS...THE WARM AIR WILL AFFECT
ALL TAF SITES. TEMPERATURES WILL RAPIDLY DECREASE AS THE LOW
CROSSES AND WEST WINDS GUSTING TO 25KT WILL ACCOMPANY A RAPID
CHANGEOVER TO SNOW.
WITH THE EXCEPTION OF THE RESPITE IN PRECIP DURING DAYLIGHT HOURS
TODAY...CIGS WILL BE MVFR AND COULD DROP TO IFR IN HEAVIER RAIN
AND/OR SNOW SHOWERS.
OUTLOOK...MVFR CEILINGS ARE EXPECTED TO CONTINUE INTO MONDAY.
MVFR CEILINGS ARE POSSIBLE WEDNESDAY THROUGH WEDNESDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR
OHZ063>065-070>074-077>080-082.
WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR OHZ026-034-035-
042>046-051-052.
WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR OHZ053>056-
060>062.
KY...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR
KYZ089>093.
IN...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR INZ058-
059-066-073>075-080.
WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR INZ050.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO/HATZOS
SHORT TERM...CONIGLIO
LONG TERM...AR
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
221 AM PST SUN FEB 1 2015
.SYNOPSIS...HIGH PRES ALOFT WILL CONTINUE TO SHIFT EAST TODAY AS A
WEAK WEATHER SYSTEM APPROACHES THE COAST. THE OFFSHORE LOW-LEVEL FLOW
WILL GRADUALLY WEAKEN DURING THE DAY...LIKELY SHIFTING TO WEAK
ONSHORE BY LATE AFTERNOON. THE FRONTAL SYSTEM IS EXPECTED TO REACH
THE COAST THIS MORNING THEN REACH THE CASCADES BY THE AFTERNOON.
OVERALL PRECIPITATION AMOUNTS WILL BE RATHER LIGHT. A MUCH WETTER
SYSTEM IMPACTS THE AREA LATE SUNDAY NIGHT AND MONDAY. COMPUTER MODEL
SOLUTIONS SHOW HIGH VARIABILITY TUESDAY THROUGH THURSDAY...BUT THE
MOST LIKELY SCENARIO IS A BRIEF DRYING TREND WEDNESDAY AND WEDNESDAY
NIGHT...FOLLOWED BY A RETURN TO A MUCH WETTER PATTERN LATE IN THE
WEEK.
&&
.SHORT TERM...TODAY THROUGH TUESDAY...MAIN STORY EARLY THIS MORNING
IS THE LOW-LEVEL OFFSHORE FLOW. AT 0930Z THE KTTD-KDLS GRADIENT WAS
AT -6.4 MB...SLIGHTLY HIGHER THAN THE 03-HR FORECAST FROM THE 06Z NAM
RUN. THIS GRADIENT IS PRODUCING WIND GUSTS OF 40-50 MPH AT THE WEST
END OF THE COLUMBIA GORGE...BUT UP TO 65 MPH AT CROWN POINT. THESE
GUSTS ARE DOWN ABOUT 10 MPH FROM LATE SAT EVENING. THE COOL POOL
APPEARS TO BE A BIT DEEPER THAN MODELS SUGGEST...AS EVIDENCED BY THE
26F DEGREE READING AT A RAWS SITE AT 3450 FT MSL IN THE S WA
CASCADES. THE OFFSHORE GRADIENT IS BEING SUPPLEMENTED BY AN
APPROACHING WEAK FRONTAL SYSTEM...ALLOWING LOWERING PRESSURE
OFFSHORE FOR INCREASING GRADIENTS. THE 06Z NAM ELIMINATES THE
OFFSHORE GRADIENT BY 21Z TODAY...BUT IT TENDS TO WEAKEN THE OFFSHORE
FLOW TOO SOON. WOULD EXPECT THE EAST WIND TO DIE OFF MORE TOWARD 00Z
OR EVEN EARLY THIS EVENING.
KRTX DUAL-POL DOPPLER RADAR SHOWING SOME PRECIP ECHOES NEARING THE
COAST AS OF 0930Z. THE MID AND HIGH CLOUD COVER HAS LIMITED FOG
FORMATION. KEUG HAD DROPPED TO ONE-QUARTER MILE EARLIER BUT HAS COME
UP TO JUST OVER 2 MILES VISIBILITY SHORTLY BEFORE 10Z. NOT MUCH
CHANGE TO THE SUNDAY FORECAST. MODELS AGREE THAT PRECIP ALONG THE
COAST SHOULD COMMENCE AROUND 12-14Z AND THEN SPREAD INLAND.
INITIALLY...THE LOW-LEVEL OFFSHORE FLOW WILL SLOW THE MOISTENING
PROCESS OF THE COLUMN...THUS NOT EXPECTING PRECIP TO BEGIN AT KPDX
UNTIL AROUND 16-18Z. THE 08Z HRRR SHOWS PRECIP BY 16Z...BUT BELIEVE
THIS MAY BE A BIT TOO SOON. IN ANY EVENT...PRECIP WITH THIS FRONTAL
SYSTEM WILL BE RATHER LIGHT...MAYBE ONE-QUARTER TO ONE-HALF INCH
TOTAL FOR THE COAST RANGE...WILLAPA HILLS AND CASCADES. PRECIP LIKELY
TO BEGIN AS SNOW IN EASTERN SKAMANIA COUNTY OF SW WA AND THE EAST
SIDE OF MT. HOOD DUE TO THE RELATIVELY DEEP COOL POOL. THIS SYSTEM
MAY NOT BE STRONG ENOUGH TO TOTALLY MIX OUT THE COLDER AIR IN THOSE
AREAS. ANY PRECIP IN THE UPPER HOOD RIVER VALLEY SHOULD STAY AS
LIQUID.
MODELS ALSO IN GENERAL AGREEMENT REGARDING THE SUN NIGHT/MON SYSTEM.
MAIN MODEL DISCREPANCIES LIE IN THE TIMING AND FOCUS OF THE HEAVIEST
QPF. THE ECMWF SEEMS TO BE A BIT FASTER AND KEEPS THE HEAVIEST QPF
OVER SWRN OREGON MON MORNING. GFS HAS THE QPF BULLS-EYE A LITTLE
FURTHER NORTH WHILE THE NAM IS JUST A TOUCH MORE N THAN THE GFS. NAM
ALSO ALSO DEVELOPS A SLIGHTLY STRONGER SURFACE LOW NEAR BUOY 029 18Z
MON WHILE THE GFS HAS IT A BIT WEAKER AND FURTHER N. BREEZY TO WINDY
SOUTH WIND WOULD DEVELOP IF THE NAM VERIFIES...ESPECIALLY ALONG THE
COAST. NAM ALSO SHOWS A SHARPER AND MORE DYNAMIC COLD FRONT. THIS
WOULD ALSO BREAK THROUGH VALLEY INVERSIONS AND WARM UP THE LOWLANDS
CONSIDERABLY...JUST BEFORE COLD FRONTAL PASSAGE. IN ADDITION...00Z
NAM BUFR SOUNDINGS SHOW THE POTENTIAL FOR SOME INSTABILITY...WITH
CAPE OF 400-800 J/KG JUST ABOVE LOW-LEVEL INVERSION. THERE IS THE
SLIM POTENTIAL MONDAY AFTERNOON FOR SOME SURFACE-BASED CONVECTION
WITH THE COLD FRONT. THE SOUNDINGS ALSO SHOW DECENT DIRECTIONAL
SHEAR WITHIN THE UNSTABLE LAYER. HAVE MAINTAINED THE SLIGHT CHANCE
OF THUNDER MONDAY AFTERNOON AND EARLY EVENING.
TOTAL QPF FOR THIS SYSTEM EXPECTED TO BE ON THE ORDER OF 1 TO 1.5
INCHES FOR THE MOUNTAINS AND 0.25 TO 0.75 FOR THE LOWLANDS. MODELS
THEN START TO DIVERGE MON NIGHT AND BEYOND. THE ECMWF BRINGS A WARM
FRONT INTO SWRN OREGON TUE MORNING....AS DOES THE NAM BUT IT HAS IT A
LITTLE MORE TO THE S...CLOSER TO THE CALIFORNIA BORDER. THE GFS IS
MORE IN BETWEEN THE TWO. THIS WARM FRONTAL FEATURE GRADUALLY DRIFTS N
TUE AFTERNOON...BUT STAYS S OF THE COLUMBIA RIVER BY 00Z WED.
THUS...SNOW LEVELS WILL BE MUCH LOWER IN THE S WA AND FAR N OREGON
CASCADES TUE...COMPARED TO AREAS S OF MT. JEFFERSON. WEISHAAR
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...MODELS SOLUTIONS VARY IN
THE MID-WEEK PERIOD. THE GFS INDICATES AN UPPER RIDGE RETURNING TO
THE PACIFIC NW WED WHILE THE ECMWF KEEPS A REMNANT WARM-FRONTAL
BAROCLINIC BOUNDARY OVER THE REGION. THERE IS A THE GEM IS MORE IN
LINE WITH THE GFS COMPARED TO THE ECMWF. MADE SOME SMALL ADJUSTEMENTS
TO THE WED AND WED NIGHT PERIODS...MAINLY TO TRIM POPS A BIT. SHOULD
THE GFS PAN OUT...FURTHER REDUCTION WOULD BE NECESSARY AND WOULD ALSO
NEED TO CONSIDER THE INCLUSION OF NIGHT NIGHT AND MORNING FOG FOR THE
INTERIOR VALLEYS. MODELS ARE IN SURPRISING AGREEMENT FOR THE END OF
THE EXTENDED PERIOD. IT LOOKS LIKE A PERIOD OF MUCH WETTER WEATHER
WILL IMPACT THE REGION LATE IN THE WEEK...AND POSSIBLY INTO NEXT
WEEKEND AS A SWATH OF SUBTROPICAL MOISTURE COMBINED WITH A SERIES OF
ATMOSPHERIC WAVES SETS UP OVER THE NE PACIFIC. THIS WEATHER PATTERN
WILL LIKELY BRING A SUBSTANTIAL AMOUNT OF RAIN TO PARTS OF THE
PACIFIC NORTHWEST. HOWEVER...CONFIDENCE IN TIMING AND AREAS OF
PRIMARY QPF FOCUS REMAIN RATHER LOW AT THIS TIME. WEISHAAR
&&
.AVIATION...THE COAST AS WELL AS NORTH AND CENTRAL WILLAMETTE
VALLEY SITES REMAINS VFR AS COLD FRONT APPROACHES THE REGION.
INCREASING CLOUDS EARLY THIS MORNING WILL LIMIT FOG DEVELOPMENT IN
THESE AREAS...THOUGH THERE IS SOME PATCHY FOG AROUND KSLE
OCCASIONALLY REDUCING CIGS/VSBYS AT THIS SITE. CIGS WILL
GRADUALLY LOWER OVER NIGHT WITH RAIN DEVELOPING AROUND 14Z ALONG
THE COAST AND CLOSER TO 16Z AT SITES IN THE WILLAMETTE VALLEY.
FURTHER SOUTH...LIFR CIGS/VSBYS AT KEUG WILL CONTINUE UNTIL
SHOWERS START TO PUSH INTO THE REGION AROUND 16Z. CIGS/VSBYS WILL
GRADUALLY IMPROVE TO MVFR AFTER FRONTAL PASSAGE THIS
AFTERNOON/EVENING.
KPDX AND APPROACHES...VFR CONDITIONS WILL PREVAIL THIS MORNING WITH
GUSTY EAST WINDS. MID AND HIGH CLOUDS INCREASE OVERNIGHT WITH
CIGS FALLING FROM 100 TO 050 AROUND 16Z SUN ALONG WITH RAIN
DEVELOPING. MAY SEE IFR CIGS WORK SOUTH ALONG THE I-5 CORRIDOR
FROM THE KKLS AREA TOWARD KPDX BUT EASTERLY OUTFLOW FROM THE GORGE
SHOULD KEEP IT AS AN IFR STRATUS DECK IF IT ARRIVES AT ALL. RAIN
PICKS UP AROUND 16Z AND CIGS FALL TO 025. EXPECT FRONTAL PASSAGE
AND A TRANSITION TO SHOWERS NEAR 23Z. -MCCOY/JBONK
&&
.MARINE...AN APPROACHING COLD FRONT IS APPROACHING OUR WATERS THIS
MORNING AND WILL MOVE THROUGH THIS MORNING. WINDS WILL INCREASE
NEAR SMALL CRAFT ADVISORY ALONG AND AHEAD OF THE FRONT THIS
MORNING. CONFIDENCE IS STILL LOW THAT GUSTS ABOVE 20 KTS WILL BE
PREVALENT ENOUGH TO WARRANT A SMALL CRAFT ADVISORY...THOUGH A FEW
GUSTS OVER 20 KTS ARE POSSIBLE...ESPECIALLY AS THE FRONT NEARS
SHORE. SEAS START TO INCREASE WITH THIS SYSTEM BUT LOOK TO REMAIN
BELOW 10 FT TODAY. A SECOND...STRONGER SYSTEM MOVES THROUGH ON
MONDAY...BRINGING A VERY GOOD CHANCE FOR SMALL CRAFT WINDS WITH
GUSTS TO 30 KTS LIKELY. THIS SYSTEM WILL ALSO INCREASE SEAS TO 10
TO 12 FT. WINDS AND SEAS START TO SUBSIDE LATE MONDAY...BRINGING
SEAS BACK DOWN TO AROUND 7 TO 8 FT BY MIDWEEK AS SHORT-LIVED HIGH
PRESSURE BUILDS BACK OVER THE REGION. MODELS ARE IN AGREEMENT THAT
AN EVEN STRONGER SYSTEM WILL MOVE THROUGH LATE THIS WEEK...WHICH
COULD GENERATE SOUTHERLY GALES AND BRING SEAS UP TO NEAR 20 FT
THURSDAY OR FRIDAY. THERE IS UNCERTAINTY IN THE TIMING AND TRACK
OF THIS SYSTEM...WHICH SHOULD GET IRONED OUT AS THE WEEK
PROGRESSES. -MCCOY
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
314 PM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT...AND CROSS THE
STATE ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA INTO MONDAY MORNING. A PERIOD OF FREEZING RAIN IS
LIKELY ACROSS THE SOUTHERN AND CENTRAL SECTIONS OF THE STATE
OVERNIGHT. ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY
AFTERNOON INTO TUESDAY...WITH LOW WIND CHILLS TUESDAY MORNING. A
COLD FRONT MOVING THROUGH WEDNESDAY WILL BE ACCOMPANIED BY SOME
LIGHT SNOW...MAINLY IN THE NORTHWESTERN HALF OF THE STATE.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
PRETTY SOLID BAND OF WAA SNOW IS PUSHING THROUGH WRN PA BUT NOT
MUCH BEHIND IT. MESO MODELS HAVE BEEN PLAYING THAT BREAK UP FOR A
LITTLE WHILE...AND IT LOOKS LIKE IT IS COMING TO FRUITION. THIS
WILL YIELD A 3-4 HOUR BREAK IN THE SNOW FOR MOST PLACES. WHILE IT
HAS BEEN SNOWING ALL DAY OUT THE WINDOW...IT STILL REALLY HAS NOT
STARTED STICKING TO ANYTHING. THIS APPEARS TO BE THE CASE ALMOST
EVERYWHERE IN THE CWA JUDGING BY WEB CAMS. BUT THE HIGHER ELEVS OF
THE LAURELS SHOULD BE GETTING WHITE ANY TIME NOW. WILL JUST WORK
THE POPS AROUND TO TRY TO SHOW THAT LITTLE BREAK...BUT IT IS SUCH
A SMALL-SCALE FEATURE THAT IT MAY JUST END UP WASHING OUT IN THE
BIGGER PICTURE. TEMPS DANCING AROUND 32F IN THE CENTRAL COS BUT
WELL INTO THE M30S IN THE SE. PRECIP THERE WILL BE VERY LIGHT
UNTIL MUCH LATER/THIS EVENING. SO...P-TYPE WILL BE DIFFICULT TO
PIN DOWN. CERTAINLY IF IT DECIDES TO SNOW HEAVILY...IT WILL BE
SNOW FOR THAT TIME...BUT WILL LIKELY BE A MIX WHEN LIGHT IN THE
S/SE. TEMPS MOVE LITTLE ALL EVENING...BUT WILL PROBABLY COOL JUST
A LITTLE WITH WET BULBING. DEWPOINTS ALREADY RISING SOME LOCALLY.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE BEST PERIOD OF SNOW CONTINUES TO LOOK LIKE IT WILL BE BETWEEN
00-09Z WITH THE WORST OF IT ACROSS THE NRN HALF OF THE AREA. THE
WARM AIR ALOFT LOOKS TO MAKE IN-ROADS ALL THE WAY TO I-80 BY
SUNRISE MONDAY. THUS...THE ICING POTENTIAL IS STILL THERE. SO
WHILE THE SNOW AMOUNTS - ESPECIALLY IF YOU ONLY MEASURE IN THE
MORNING - WILL BE LOWER THAN PREVIOUSLY ADVERTISED IN THE SRN HALF
OF THE AREA...THERE IS STILL SOME /WEAK/ JUSTIFICATION FOR HOLDING
ONTO THE WARNING ALONG THE RTE 22 CORRIDOR...FOR NOW.
THE QPF IS A MIXED-BAG OF SIGNALS RIGHT NOW. GFS AND EURO ARE
HOLDING ONTO 0.80 OR MORE IN THE NRN HALF OF THE AREA...WITH ONLY
REAL SNOW THERE. THE NAM AND THE SREF MEAN TOTALS THERE ARE ONLY
ABOUT 0.50. WILL CONTINUE WITH THE PARTY LINE OF 8-10 FOR A STORM
TOTAL...BUT REWORKED THE NUMBERS DOWN BARELY AN INCH ON THE WHOLE
SO THE TERRIBLE DARK BLUE OF 10-14 DOES NOT HIT PEOPLE IN THE
FACE. AGAIN...JUST HALF AN INCH TO AN INCH OF A DOWNWARD MOVE ON
THE SNOW. THIS IS DUE TO THE RELATIVELY HIGH UNCERTAINTY AT THIS
RANGE. STILL LOOKS LIKE A SOLID WARNING ANY WAY YOU SLICE IT UP
FOR OUR ENTIRE NRN HALF. SOME PRETTY WICKED SF RATES WILL BE HAD
OVERNIGHT AND VERY EARLY MONDAY IN THE NORTH AND PERHAPS AS FAR S
AS STATE COLLEGE AND SUNBURY BUT MOST LIKELY - THE HEAVIEST SNOW
WILL BE JUST TO THE NORTH OF THOSE TWO CITIES.
PRECIP CUTS OFF PRETTY QUICKLY AFTER 12Z/14Z IN THE CENTRAL COS.
THE EAST MAY SEE PRECIP LINGER INTO THE MID MORNING AS THE COLD
AIR MOVES IN AND TEMPS DROP. AFTER WHAT MAY ONLY BE A BRIEF
BREAK...THE NW WINDS WILL UPSLOPE INTO THE ALLEGHENIES AND
LAURELS. CAA WILL CREATE NUMEROUS SHSN OVER THE WRN HIGH TERRAIN
AND FLURRIES ELSEWHERE. THERE MAY EVEN BE SOME DECENT SHSN AS THE
PRECIP ENDS IN THE SERN THIRD OF THE AREA. YET ANOTHER REASON TO
NOT MONKEY WITH THE WARNINGS/ADVYS JUST YET. IT COULD BE A MESSY
COMMUTE FOR GROUNDHOG MORNING. WINDS WILL GET STRONG AND RATHER
GUSTY - ESP ON THE HILL TOPS AND IN THE SERN THIRD/DOWNSLOPE AREAS
CLOSEST TO THE DEEPENING LOW MOVING OFF THE COAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS POSSIBLY NEEDING A WIND CHILL ADVISORY /-15F/
MON NIGHT INTO EARLY TUE.
ENSEMBLE MEAN 5H PATTERN SHOWS AN ALBERTA CLIPPER DIVING SE INTO
THE REGION WED/THU. ALL MED RANGE GUIDANCE TRACKS ASSOC SFC LOW
NORTH OF THE STATE EARLY WED...LIKELY PRODUCING A BIT OF LGT SNOW
ACROSS NORTHERN PA. A WEAK LOW ON TRAILING COLD FRONT COULD
SUPPORT SOME LINGERING LGT SNOW ACROSS THE REGION /MAINLY
ALLEGHENIES/ INTO EARLY THURSDAY.
MODERATING TEMPS AHEAD OF CLIPPER COULD RESULT IN A DAY OF NEAR
NORMAL HIGHS WEDNESDAY. HOWEVER...A REINFORCING SHOT OF ARCTIC
AIR LOOKS NEARLY CERTAIN BEHIND CLIPPER LATE THIS WEEK.
NO RESPITE FROM THE BLW NORMAL TEMPS IN THE EXTENDED...AS LATEST
MED RANGE GUIDANCE MAINTAINS UPPER LVL TROF AXIS ACROSS THE
NORTHEAST CONUS.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 17Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV/KIPT BTWN 19Z-21Z. ACROSS THE
SOUTHEAST COUNTIES...LATEST MDL DATA SUGGESTS A BAND OF LGT
SNOW/VIS REDUCTIONS COULD COME THROUGH BTWN 22Z-01Z AT KMDT/KLNS.
HOWEVER...CONFIDENCE IN IFR CONDS WILL INCREASE MARKEDLY AT
KMDT/KLNS BTWN 03Z-06Z...AS HEAVIEST SNOW ARRIVES.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. MARGINAL LLWS REMAINS
A POSSIBILITY LATE TONIGHT ACROSS SOUTHERN PA...AS CORE OF STRONG
WINDS ALOFT SLIDES ACROSS THE AREA. HOWEVER...LATEST MODEL
SOUNDINGS SUGGEST MOST PLACES WILL REMAIN JUST BLW CRITERIA.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS. FOCUS WILL
SHIFT TOWARD STRONG GUSTY WINDS MON PM. GUSTS TO ARND 40KTS ARE
POSSIBLE MON AFTN AND EVENING...AS STRENGTHENING STORM SYSTEM
PASSES EAST OF PA.
OUTLOOK...
MON...AM RAIN/SNOW AND LOW CIGS. PM GUSTY NW WINDS.
TUE...NO SIG WX EXPECTED.
WED...AM LGT SNOW POSSIBLE NW MTNS.
THU...AM LGT SNOW POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...FITZGERALD
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
206 PM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT...AND CROSS THE
STATE ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA INTO MONDAY MORNING. A PERIOD OF FREEZING RAIN IS
LIKELY ACROSS THE SOUTHERN AND CENTRAL SECTIONS OF THE STATE
OVERNIGHT. ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY
AFTERNOON INTO TUESDAY...WITH LOW WIND CHILLS TUESDAY MORNING. A
COLD FRONT MOVING THROUGH WEDNESDAY WILL BE ACCOMPANIED BY SOME
LIGHT SNOW...MAINLY IN THE NORTHWESTERN HALF OF THE STATE.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
PRETTY SOLID BAND OF WAA SNOW IS PUSHING THROUGH WRN PA BUT NOT
MUCH BEHIND IT. MESO MODELS HAVE BEEN PLAYING THAT BREAK UP FOR A
LITTLE WHILE...AND IT LOOKS LIKE IT IS COMING TO FRUITION. THIS
WILL YIELD A 3-4 HOUR BREAK IN THE SNOW FOR MOST PLACES. WHILE IT
HAS BEEN SNOWING ALL DAY OUT THE WINDOW...IT STILL REALLY HAS NOT
STARTED STICKING TO ANYTHING. THIS APPEARS TO BE THE CASE ALMOST
EVERYWHERE IN THE CWA JUDGING BY WEB CAMS. BUT THE HIGHER ELEVS OF
THE LAURELS SHOULD BE GETTING WHITE ANY TIME NOW. WILL JUST WORK
THE POPS AROUND TO TRY TO SHOW THAT LITTLE BREAK...BUT IT IS SUCH
A SMALL-SCALE FEATURE THAT IT MAY JUST END UP WASHING OUT IN THE
BIGGER PICTURE. TEMPS DANCING AROUND 32F IN THE CENTRAL COS BUT
WELL INTO THE M30S IN THE SE. PRECIP THERE WILL BE VERY LIGHT
UNTIL MUCH LATER/THIS EVENING. SO...P-TYPE WILL BE DIFFICULT TO
PIN DOWN. CERTAINLY IF IT DECIDES TO SNOW HEAVILY...IT WILL BE
SNOW FOR THAT TIME...BUT WILL LIKELY BE A MIX WHEN LIGHT IN THE
S/SE. TEMPS MOVE LITTLE ALL EVENING...BUT WILL PROBABLY COOL JUST
A LITTLE WITH WET BULBING. DEWPOINTS ALREADY RISING SOME LOCALLY.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE BEST PERIOD OF SNOW CONTINUES TO LOOK LIKE IT WILL BE BETWEEN
00-09Z WITH THE WORST OF IT ACROSS THE NRN HALF OF THE AREA. THE
WARM AIR ALOFT LOOKS TO MAKE IN-ROADS ALL THE WAY TO I-80 BY
SUNRISE MONDAY. THUS...THE ICING POTENTIAL IS STILL THERE. SO
WHILE THE SNOW AMOUNTS - ESPECIALLY IF YOU ONLY MEASURE IN THE
MORNING - WILL BE LOWER THAN PREVIOUSLY ADVERTISED IN THE SRN HALF
OF THE AREA...THERE IS STILL SOME /WEAK/ JUSTIFICATION FOR HOLDING
ONTO THE WARNING ALONG THE RTE 22 CORRIDOR...FOR NOW.
THE QPF IS A MIXED-BAG OF SIGNALS RIGHT NOW. GFS AND EURO ARE
HOLDING ONTO 0.80 OR MORE IN THE NRN HALF OF THE AREA...WITH ONLY
REAL SNOW THERE. THE NAM AND THE SREF MEAN TOTALS THERE ARE ONLY
ABOUT 0.50. WILL CONTINUE WITH THE PARTY LINE OF 8-10 FOR A STORM
TOTAL...BUT REWORKED THE NUMBERS DOWN BARELY AN INCH ON THE WHOLE
SO THE TERRIBLE DARK BLUE OF 10-14 DOES NOT HIT PEOPLE IN THE
FACE. AGAIN...JUST HALF AN INCH TO AN INCH OF A DOWNWARD MOVE ON
THE SNOW. THIS IS DUE TO THE RELATIVELY HIGH UNCERTAINTY AT THIS
RANGE. STILL LOOKS LIKE A SOLID WARNING ANY WAY YOU SLICE IT UP
FOR OUR ENTIRE NRN HALF. SOME PRETTY WICKED SF RATES WILL BE HAD
OVERNIGHT AND VERY EARLY MONDAY IN THE NORTH AND PERHAPS AS FAR S
AS STATE COLLEGE AND SUNBURY BUT MOST LIKELY - THE HEAVIEST SNOW
WILL BE JUST TO THE NORTH OF THOSE TWO CITIES.
PRECIP CUTS OFF PRETTY QUICKLY AFTER 12Z/14Z IN THE CENTRAL COS.
THE EAST MAY SEE PRECIP LINGER INTO THE MID MORNING AS THE COLD
AIR MOVES IN AND TEMPS DROP. AFTER WHAT MAY ONLY BE A BRIEF
BREAK...THE NW WINDS WILL UPSLOPE INTO THE ALLEGHENIES AND
LAURELS. CAA WILL CREATE NUMEROUS SHSN OVER THE WRN HIGH TERRAIN
AND FLURRIES ELSEWHERE. THERE MAY EVEN BE SOME DECENT SHSN AS THE
PRECIP ENDS IN THE SERN THIRD OF THE AREA. YET ANOTHER REASON TO
NOT MONKEY WITH THE WARNINGS/ADVYS JUST YET. IT COULD BE A MESSY
COMMUTE FOR GROUNDHOG MORNING. WINDS WILL GET STRONG AND RATHER
GUSTY - ESP ON THE HILL TOPS AND IN THE SERN THIRD/DOWNSLOPE AREAS
CLOSEST TO THE DEEPENING LOW MOVING OFF THE COAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 17Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV/KIPT BTWN 19Z-21Z. ACROSS THE
SOUTHEAST COUNTIES...LATEST MDL DATA SUGGESTS A BAND OF LGT
SNOW/VIS REDUCTIONS COULD COME THROUGH BTWN 22Z-01Z AT KMDT/KLNS.
HOWEVER...CONFIDENCE IN IFR CONDS WILL INCREASE MARKEDLY AT
KMDT/KLNS BTWN 03Z-06Z...AS HEAVIEST SNOW ARRIVES.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. MARGINAL LLWS REMAINS
A POSSIBILITY LATE TONIGHT ACROSS SOUTHERN PA...AS CORE OF STRONG
WINDS ALOFT SLIDES ACROSS THE AREA. HOWEVER...LATEST MODEL
SOUNDINGS SUGGEST MOST PLACES WILL REMAIN JUST BLW CRITERIA.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS. FOCUS WILL
SHIFT TOWARD STRONG GUSTY WINDS MON PM. GUSTS TO ARND 40KTS ARE
POSSIBLE MON AFTN AND EVENING...AS STRENGTHENING STORM SYSTEM
PASSES EAST OF PA.
OUTLOOK...
MON...AM RAIN/SNOW AND LOW CIGS. PM GUSTY NW WINDS.
TUE...NO SIG WX EXPECTED.
WED...AM LGT SNOW POSSIBLE NW MTNS.
THU...AM LGT SNOW POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1258 PM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY SOME REALLY PATCHY AND LIGHT SNOW IS FALLING OVER THE WRN
HALF OF THE AREA. BUT SOME MORE-INTENSE BANDS MOVING OVER PBZ/S
AREA AND INTO THE LAURELS ATTM. THESE SHOULD MAKE SOME
ACCUMULATIONIN THE WEST/CENTRAL COS BY MID- AFTERNOON...BUT THE
SUN IS MANAGING TO MAKE A BRIGHT SPOT IN THE CLOUDS OVER STATE
COLLEGE RIGHT NOW. IT IS STILL SNOWING WITH VSBY LT 4SM.
BUT...ANYTHING MORE THAN A FEW TENTHS OF SNOW ACCUM ARE UNLIKELY
BEFORE MID AFTN. MESO MDLS HINT AT A BREAK AFTER A FEW BANDS OF
SNOW SLIDE SW-NE THRU THE AREA THIS AFTN...THEN THE SNOW MOVES
BACK IN AND INTENSIFIES FROM SW-NE THIS EVENING. ALL THIS IS
PRETTY MUCH UNCHANGED.
WITH THAT SAID...
WITH EACH PASSING MODEL CYCLE IT LOOKS LIKE WE WILL GET LESS SNOW
ON THE WHOLE...WHETHER DUE TO LOWER QPF DUE TO ONLY A COUPLE OF
HEAVIER BANDS AND PERHAPS ONLY ONE 3-6 HR PERIOD OF HEAVY SNOW -
OR DUE TO MORE RAIN/MIX OCCURRING IN THE SOUTHERN HALF OF THE
AREA. HOWEVER...IT HAS BARELY STARTED SNOWING. LETS AT LEAST LET
IT START TO PLAY OUT. WILL NOT MAKE ANY TWEAKS TO SNOW OR ICE
ACCUMS OR CHANGES TO HEADLINES AT THIS POINT. BUT THE LATER
UPDATES TODAY MAY JUST FOLLOW THIS MILDER/DRIER TREND IF THE
NEWER GFS AND EC LOOK SIMILARLY MILD AND LESS WET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUNTS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 17Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV/KIPT BTWN 19Z-21Z. ACROSS THE
SOUTHEAST COUNTIES...LATEST MDL DATA SUGGESTS A BAND OF LGT
SNOW/VIS REDUCTIONS COULD COME THROUGH BTWN 22Z-01Z AT KMDT/KLNS.
HOWEVER...CONFIDENCE IN IFR CONDS WILL INCREASE MARKEDLY AT
KMDT/KLNS BTWN 03Z-06Z...AS HEAVIEST SNOW ARRIVES.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. MARGINAL LLWS REMAINS
A POSSIBILITY LATE TONIGHT ACROSS SOUTHERN PA...AS CORE OF STRONG
WINDS ALOFT SLIDES ACROSS THE AREA. HOWEVER...LATEST MODEL
SOUNDINGS SUGGEST MOST PLACES WILL REMAIN JUST BLW CRITERIA.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS. FOCUS WILL
SHIFT TOWARD STRONG GUSTY WINDS MON PM. GUSTS TO ARND 40KTS ARE
POSSIBLE MON AFTN AND EVENING...AS STRENGTHENING STORM SYSTEM
PASSES EAST OF PA.
OUTLOOK...
MON...AM RAIN/SNOW AND LOW CIGS. PM GUSTY NW WINDS.
TUE...NO SIG WX EXPECTED.
WED...AM LGT SNOW POSSIBLE NW MTNS.
THU...AM LGT SNOW POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1043 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY SOME REALLY PATCHY AND LIGHT SNOW IS FALLING OVER THE WRN
HALF OF THE AREA. BUT SOME MORE-INTENSE BANDS MOVING OVER PBZ/S
AREA AND INTO THE LAURELS ATTM. THESE SHOULD MAKE SOME
ACCUMULATIONIN THE WEST/CENTRAL COS BY MID- AFTERNOON...BUT THE
SUN IS MANAGING TO MAKE A BRIGHT SPOT IN THE CLOUDS OVER STATE
COLLEGE RIGHT NOW. IT IS STILL SNOWING WITH VSBY LT 4SM.
BUT...ANYTHING MORE THAN A FEW TENTHS OF SNOW ACCUM ARE UNLIKELY
BEFORE MID AFTN. MESO MDLS HINT AT A BREAK AFTER A FEW BANDS OF
SNOW SLIDE SW-NE THRU THE AREA THIS AFTN...THEN THE SNOW MOVES
BACK IN AND INTENSIFIES FROM SW-NE THIS EVENING. ALL THIS IS
PRETTY MUCH UNCHANGED.
WITH THAT SAID...
WITH EACH PASSING MODEL CYCLE IT LOOKS LIKE WE WILL GET LESS SNOW
ON THE WHOLE...WHETHER DUE TO LOWER QPF DUE TO ONLY A COUPLE OF
HEAVIER BANDS AND PERHAPS ONLY ONE 3-6 HR PERIOD OF HEAVY SNOW -
OR DUE TO MORE RAIN/MIX OCCURRING IN THE SOUTHERN HALF OF THE
AREA. HOWEVER...IT HAS BARELY STARTED SNOWING. LETS AT LEAST LET
IT START TO PLAY OUT. WILL NOT MAKE ANY TWEAKS TO SNOW OR ICE
ACCUMS OR CHANGES TO HEADLINES AT THIS POINT. BUT THE LATER
UPDATES TODAY MAY JUST FOLLOW THIS MILDER/DRIER TREND IF THE
NEWER GFS AND EC LOOK SIMILARLY MILD AND LESS WET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUNTS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 15Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV ARND 16Z AND AT KIPT ARND
18Z. ACROSS THE SOUTHEAST COUNTIES...SOME MINOR VIS REDUCTIONS
APPEAR LIKELY THIS AFTN IN LGT SNOW. HOWEVER...IFR CONDS WILL LKLY
HOLD OFF AT KMDT/KLNS UNTIL LATE THIS EVENING.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. LLWS REMAINS A
POSSIBILITY LATE TONIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES
THROUGH.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS.
OUTLOOK...
MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM
MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT.
TUE...NO SIG WX.
WED...MVFR IN SHSN NW...VFR SE.
THU...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1042 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BROKEN SHIELD OF LIGHT SNOW DEVELOPING WELL OUT AHEAD OF SFC LOW
OVER EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY
DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY.
THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS
BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER
OF PENNSYLVANIA BY MONDAY MORNING.
EXPANDED POPS SLIGHTLY EARLY THIS MORNING AS RADAR TRENDS INDICATE
A FEW POCKETS OF LIGHT SNOW WILL REACH INTO THE LOWER SUSQ FOR A
TIME THIS MORNING. BACK EDGE OF INITIAL SNOWFALL LIES ACROSS
CENTRAL OH/IN THIS MORNING...AND EXPECT THIS LULL TO REACH INTO
AT LEAST PORTIONS OF CENTRAL AND SOUTHERN PA FOR A GOOD PART OF
THIS AFTERNOON.
ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE
THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE
ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN
FACT...HI RES HRRR AND HRW-ARW CONTINUE TO SHOW FRACTURED
MOTHEATEN PRECIP SHIELD DECREASING BY AFTERNOON...WITH A FEW TO
SEVERAL HOURS IN BETWEEN IN AND MAIN PRECIP EVENT SPINNING UP THIS
EVENING AS SFC LOW PUSHES INTO THE OHIO VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUNTS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 15Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV ARND 16Z AND AT KIPT ARND
18Z. ACROSS THE SOUTHEAST COUNTIES...SOME MINOR VIS REDUCTIONS
APPEAR LIKELY THIS AFTN IN LGT SNOW. HOWEVER...IFR CONDS WILL LKLY
HOLD OFF AT KMDT/KLNS UNTIL LATE THIS EVENING.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. LLWS REMAINS A
POSSIBILITY LATE TONIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES
THROUGH.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS.
OUTLOOK...
MON...AM RAIN/SNOW AND LOW CIGS. PM GUSTY NW WINDS.
TUE...NO SIG WX EXPECTED.
WED...AM LGT SNOW POSSIBLE NW MTNS.
THU...LGT SNOW POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1018 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BROKEN SHIELD OF LIGHT SNOW DEVELOPING WELL OUT AHEAD OF SFC LOW
OVER EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY
DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY.
THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS
BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER
OF PENNSYLVANIA BY MONDAY MORNING.
EXPANDED POPS SLIGHTLY EARLY THIS MORNING AS RADAR TRENDS INDICATE
A FEW POCKETS OF LIGHT SNOW WILL REACH INTO THE LOWER SUSQ FOR A
TIME THIS MORNING. BACK EDGE OF INITIAL SNOWFALL LIES ACROSS
CENTRAL OH/IN THIS MORNING...AND EXPECT THIS LULL TO REACH INTO
AT LEAST PORTIONS OF CENTRAL AND SOUTHERN PA FOR A GOOD PART OF
THIS AFTERNOON.
ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE
THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE
ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN
FACT...HI RES HRRR AND HRW-ARW CONTINUE TO SHOW FRACTURED
MOTHEATEN PRECIP SHIELD DECREASING BY AFTERNOON...WITH A FEW TO
SEVERAL HOURS IN BETWEEN IN AND MAIN PRECIP EVENT SPINNING UP THIS
EVENING AS SFC LOW PUSHES INTO THE OHIO VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUNTS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
DETERIORATING FLYING CONDS EXPECTED THIS AFTN AND EVENING...AS LOW
PRES APPROACHES FROM THE MIDWEST...SPREADING SNOW AND LOWERING
CIGS ACROSS CENTRAL PA. AT 15Z...IFR CONDS ALREADY NOTED ACROSS
WESTERN PA. UPSTREAM RADAR RETURNS AND LATEST HRRR OUTPUT SUGGESTS
IFR CONDS WILL DEVELOP AT KAOO/KUNV ARND 16Z AND AT KIPT ARND
18Z. ACROSS THE SOUTHEAST COUNTIES...SOME MINOR VIS REDUCTIONS
APPEAR LIKELY THIS AFTN IN LGT SNOW. HOWEVER...IFR CONDS WILL LKLY
HOLD OFF AT KMDT/KLNS UNTIL LATE THIS EVENING.
WARMER AIR WORKING INTO THE STATE WILL CHANGE SNOW TO EITHER RAIN
OR FZRA ACROSS THE SOUTHERN HALF OF THE STATE LATE TONIGHT.
HOWEVER....WIDESPREAD IFR TO LIFR CONDS EXPECTED EVERYWHERE IN
CONTINUING PRECIP AND LOW CIGS RESULTING FROM MOIST SE FLOW
ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. LLWS REMAINS A
POSSIBILITY LATE TONIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES
THROUGH.
MARKED IMPROVEMENT IS EXPECTED BTWN 15Z-18Z MONDAY...AS LOW PRES
PASSES EAST OF THE AREA...AND DRIER NW FLOW DEVELOPS.
OUTLOOK...
MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM
MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT.
TUE...NO SIG WX.
WED...MVFR IN SHSN NW...VFR SE.
THU...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
712 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BROKEN SHIELD OF LIGHT SNOW DEVELOPING WELL OUT AHEAD OF SFC LOW
OVER EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY
DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY.
THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS
BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER
OF PENNSYLVANIA BY MONDAY MORNING.
EXPANDED POPS SLIGHTLY EARLY THIS MORNING AS RADAR TRENDS INDICATE
A FEW POCKETS OF LIGHT SNOW WILL REACH INTO THE LOWER SUSQ FOR A
TIME THIS MORNING. BACK EDGE OF INITIAL SNOWFALL LIES ACROSS
CENTRAL OH/IN THIS MORNING...AND EXPECT THIS LULL TO REACH INTO
AT LEAST PORTIONS OF CENTRAL AND SOUTHERN PA FOR A GOOD PART OF
THIS AFTERNOON.
ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE
THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE
ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN
FACT...HI RES HRRR AND HRW-ARW CONTINUE TO SHOW FRACTURED
MOTHEATEN PRECIP SHIELD DECREASING BY AFTERNOON...WITH A FEW TO
SEVERAL HOURS IN BETWEEN IN AND MAIN PRECIP EVENT SPINNING UP THIS
EVENING AS SFC LOW PUSHES INTO THE OHIO VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUNTS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LOWERING CONDITIONS WILL OCCUR FROM WEST TO EAST...BEGINNING SO
FAR AT BFD AND JST AT LIFR AND IFR RESPECTIVELY AS DEEPENING
MOISTURE /AND THE ONSET OF LIGHT SNOW/ STREAKS EASTWARD ALONG AND
AHEAD OF A SLOWLY SWD SAGGING COLD FRONT.
WIDESPREAD IFR TO LIFR CONDITIONS ARE IN STORE THIS
AFTERNOON...OVERNIGHT AND INTO EARLY MON AS HEAVIER SNOW IMPACTS
THE NORTHERN HALF OF THE STATE. THE SOUTHERN HALF WILL SEE A
WINTRY MIX WORK INTO THE SOUTHERN TAF SITES...FROM JST AND
AOO...TO KMDT- KLNS AREA WITH POTENTIAL FOR ICING. THIS IS DUE TO
WARM AIR ADVECTION INTO THE MID LEVELS...AND COLD TEMPERATURES AT
THE SURFACE. LLWS POSS SUNDAY NIGHT ACROSS THE S/SE AS LOW LEVEL
JET ROTATES THROUGH.
OUTLOOK...
SUN...WIDESPREAD IFR-MVFR CIGS AND IFR VSBYS DEVELOPING DURING THE
MORNING-EARLY AFTERNOON HOURS. LLWS POSS SUN NIGHT SE.
MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM
MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT.
TUE...NO SIG WX.
WED...MVFR IN SHSN NW...VFR SE.
THU...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
621 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BROKEN SHIELD OF LIGHT SNOW DEVELOPING WELL OUT AHEAD OF SFC LOW
OVER EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY
DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY.
THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS
BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER
OF PENNSYLVANIA BY MONDAY MORNING.
EXPANDED POPS SLIGHTLY EARLY THIS MORNING AS RADAR TRENDS INDICATE
A FEW POCKETS OF LIGHT SNOW WILL REACH INTO THE LOWER SUSQ FOR A
TIME THIS MORNING. BACK EDGE OF INITIAL SNOWFALL LIES ACROSS
CENTRAL OH/IN THIS MORNING...AND EXPECT THIS LULL TO REACH INTO
AT LEAST PORTIONS OF CENTRAL AND SOUTHERN PA FOR A GOOD PART OF
THIS AFTERNOON.
ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE
THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE
ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN
FACT...HI RES HRRR AND HRW-ARW CONTINUE TO SHOW FRACTURED
MOTHEATEN PRECIP SHIELD DECREASING BY AFTERNOON...WITH A FEW TO
SEVERAL HOURS IN BETWEEN IN AND MAIN PRECIP EVENT SPINNING UP THIS
EVENING AS SFC LOW PUSHES INTO THE OHIO VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUTNS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
THE RIDGE CONTINUES TO WEAKEN AS THE SHALLOW ARTIC AIR HAS MAINLY
DISSIPATED AS ITS MOVED EASTWARD. THIS HAS DELAYED THE ONSET OF
MVFR CIGS /AND ANY GRADUALLY DETERIORATING VSBYS TO IFR. THE ONSET
OF CONDITIONS HAS BEEN PUSHED BACK. THE LOWERING CONDITIONS WILL
OCCUR FROM WEST TO EAST BETWEEN 11-18Z AS DEEPENING MOISTURE /AND
THE ONSET OF LIGHT SNOW/ STREAKS EASTWARD ALONG AND AHEAD OF A
SLOWLY SWD SAGGING COLD FRONT.
WIDESPREAD IFR TO LIFR CONDITIONS ARE IN STORE FOR LATE SUNDAY
INTO EARLY MON AS HEAVIER SNOW IMPACTS THE NORTHERN HALF OF THE
STATE. THE SOUTHERN HALF WILL SEE A WINTRY MIX WORK INTO THE
SOUTHERN TAF SITES...FROM JST AND AOO...TO KMDT- KLNS AREA WITH
POTENTIAL FOR ICING. THIS IS DUE TO WARM AIR ADVECTION INTO THE
MID LEVELS...AND COLD TEMPERATURES AT THE SURFACE. LLWS POSS
SUNDAY NIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES THROUGH.
OUTLOOK...
SUN...WIDESPREAD IFR-MVFR CIGS AND IFR VSBYS DEVELOPING DURING THE
MORNING-EARLY AFTERNOON HOURS. LLWS POSS SUN NIGHT SE.
MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM
MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT.
TUE...NO SIG WX.
WED...MVFR IN SHSN NW...VFR SE.
THU...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM EST MONDAY FOR PAZ004>006-
010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 8 AM EST MONDAY FOR PAZ033>036-
064>066.
WINTER STORM WARNING UNTIL 8 AM EST MONDAY FOR PAZ024>028-056-
057-059-063.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
424 AM EST SUN FEB 1 2015
.SYNOPSIS...
LOW PRESSURE WILL CROSS THE CENTRAL MISSISSIPPI RIVER VALLEY
TODAY AND MOVE INTO THE OHIO VALLEY TONIGHT...AND CROSS THE STATE
ON MONDAY. THIS WILL PRODUCE WIDESPREAD WINTRY PRECIPITATION
ACROSS THE AREA THIS AFTERNOON INTO MONDAY. A PERIOD OF FREEZING
RAIN IS LIKELY ACROSS THE SOUTH AND CENTRAL SECTIONS TONIGHT.
ANOTHER SHOT OF ARCTIC AIR WILL FOLLOW FOR MONDAY AFTERNOON INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT PRECIPITATION DEVELOPING WELL OUT AHEAD OF SFC LOW OVER
EASTERN KANSAS THIS MORNING...ALONG A COLD FRONTAL BOUNDARY
DROPPING SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND OHIO VALLEY.
THE AFOREMENTIONED LOW PRESSURE CENTER WILL TRACK ALONG THIS
BOUNDARY THIS AFTERNOON AND TONIGHT...AND ACROSS THE SOUTHERN TIER
OF PENNSYLVANIA BY MONDAY MORNING.
ALL HEADLINES RETAINED FOR THIS FORECAST CYCLE. MAIN CONCERNS ARE
THAT POPS WERE TOO HIGH TO BEGIN THE STORM THIS AFTERNOON...WHERE
ONLY VERY LIGHT AMOUNTS OF QPF AND SNOW ARE EXPECTED. IN
FACT...HI RES HRRR AND HRW-ARW SHOW A FRACTURED MOTHEATEN PRECIP
SHIELD AT BEST REACHING ACROSS THE ALLEGHENIES LATE THIS MORNING
AND AFTERNOON AND LARGELY DISSIPATING DURING THE MID TO LATE
AFTERNOON HOURS. THINK THERE WILL BE A SIZABLE LULL IN
PRECIPITATION FOR MANY AREAS THIS AFTERNOON BEFORE THE MAIN EVENT
APPROACHES THIS EVENING AND LATER TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
LOW PRESSURE MOVES UP THE OHIO RIVER TONIGHT. BY MONDAY MORNING
IT SHOULD BE OVER KPIT...AND ROLL OVER THE SOUTHERN HALF OF THE
LOCAL AREA. MAIN QPF FALLS IN THE 03Z TO 09Z TIMEFRAME FOR MANY...
AND THIS SIX HOUR PERIOD WILL BE CRITICAL FOR SNOW ACCUMS OVER THE
CENTRAL MOUNTAINS...JUST NORTH OF THE CHANGEOVER ZONE. FASTER/
GREATER MIXING WILL DECREASE SNOW AMOUNTS SUBSTANTIALLY. FOR NOW
HAVE NUDGED THE MIXING ZONE NORTH AND DECREASED SNOW AMOUNTS SOUTH
OF INTERSTATE 80 INTO THE 4-6" RANGE. AS A RESULT...GREATER FZRA
POTENTIAL EXISTS WITH THIS SOLUTION THAN PREVIOUS THINKING.
WHILE THE FARTHER NORTH/WARMER SOLUTION WILL CUT DOWN THE SNOW
AMOUNTS IN THE CENTRAL ZONES...WARNING CRITERIA SNOWFALL IS
EXPECTED NORTH OF INTERSTATE 80. ADVY AND SUB ADVISORY SNOW
AMOUTNS ARE EXPECTED ACROSS THE SOUTHERN THIRD OF CENTRAL PA...
BUT THE CHANCE FOR ICING IS ENOUGH TO WARRANT AT LEAST AN ADVY
FOR THEM.
SFC LOW RAPIDLY TRACKS EAST OF THE AREA BY MIDDAY MONDAY...WITH
COLDER AIR POURING BACK INTO THE COMMONWEALTH ON THE BACKSIDE OF
THE LOW. EXPECT LITTLE IF ANY ADDITIONAL SNOW ACCUMULATION BY MON
AFTERNOON ACROSS THE NORTH. PRECIP WILL HAVE SHUT OFF ACROSS
CENTRAL AND SOUTHERN AREAS BY MIDDAY. SHARPLY COLDER AIR IS POISED
TO OVERSPREAD CENTRAL PA AGAIN ON MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
MAIN IMPACTS FROM WINTER STORM WILL HAVE MOVED AWAY FROM REGION BY
MON NIGHT...BUT ARCTIC AIR PUSHING IN WILL BRING A VERY COLD
NIGHT WITH LOWS BOTTOMING OUT IN THE SINGLE DIGITS SOUTH AND BELOW
ZERO NORTH. THOUGH STRONGER WINDS IN THE EVENING WILL BE GRADUALLY
DIMINISHING OVERNIGHT...ENOUGH OF A BREEZE WILL REMAIN TO DROP
WIND CHILL VALUES BELOW ZERO FOR ALL...WITH NORTHERN MTNS AND
LAUREL HIGHLANDS LIKELY NEEDING A WIND CHILL ADVISORY /-15F/ MON
NIGHT INTO EARLY TUE. THIS COULD ADD TO STORM-RELATED
IMPACTS...INCLUDING POTENTIAL FOR PATCHY BLACK ICE.
HIGH PRESSURE WILL BRING COLD BUT GENERALLY QUIET WEATHER INTO
MIDWEEK. A WEAK SYSTEM MOVES THROUGH WED THAT MAY BRING LIGHT
ACCUMS TO THE NW HALF /BEFORE THE SYSTEM DEEPENS MORE RAPIDLY OVER
NEW ENGLAND/...WHICH WILL BE FOLLOWED BY A SHOT OF MORE ARCTIC AIR
AS COLD HIGH PRESSURE BUILDS IN FOR THU INTO FRI - INCLUDING A
RETURN OF BELOW ZERO WIND CHILLS.
TEMPS MODERATE A BIT...BUT REMAIN BELOW NORMAL...ON SAT. ANOTHER
LOW PRESSURE AREA MAY IMPACT THE REGION ON SUNDAY...BUT AT THIS
TIME IT LOOKS TO BE ON THE WEAKER SIDE.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
THE RIDGE CONTINUES TO WEAKEN AS THE SHALLOW ARTIC AIR HAS MAINLY
DISSIPATED AS ITS MOVED EASTWARD. THIS HAS DELAYED THE ONSET OF
MVFR CIGS /AND ANY GRADUALLY DETERIORATING VSBYS TO IFR. THE ONSET
OF CONDITIONS HAS BEEN PUSHED BACK. THE LOWERING CONDITIONS WILL
OCCUR FROM WEST TO EAST BETWEEN 11-18Z AS DEEPENING MOISTURE /AND
THE ONSET OF LIGHT SNOW/ STREAKS EASTWARD ALONG AND AHEAD OF A
SLOWLY SWD SAGGING COLD FRONT.
WIDESPREAD IFR TO LIFR CONDITIONS ARE IN STORE FOR LATE SUNDAY
INTO EARLY MON AS HEAVIER SNOW IMPACTS THE NORTHERN HALF OF THE
STATE. THE SOUTHERN HALF WILL SEE A WINTRY MIX WORK INTO THE
SOUTHERN TAF SITES...FROM JST AND AOO...TO KMDT- KLNS AREA WITH
POTENTIAL FOR ICING. THIS IS DUE TO WARM AIR ADVECTION INTO THE
MID LEVELS...AND COLD TEMPERATURES AT THE SURFACE. LLWS POSS
SUNDAY NIGHT ACROSS THE S/SE AS LOW LEVEL JET ROTATES THROUGH.
OUTLOOK...
SUN...WIDESPREAD IFR-MVFR CIGS AND IFR VSBYS DEVELOPING DURING THE
MORNING-EARLY AFTERNOON HOURS. LLWS POSS SUN NIGHT SE.
MON...REDUCED CONDS EARLY...GRADUALLY IMPROVING AS THE STORM
MOVES AWAY FROM THE AREA. LLWS POSS MON AFT/NIGHT.
TUE...NO SIG WX.
WED...MVFR IN SHSN NW...VFR SE.
THU...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 1 PM EST MONDAY
FOR PAZ004>006-010>012-017>019-037-041-042-045-046-049>053-058.
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 8 AM EST
MONDAY FOR PAZ033>036-064>066.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 8 AM EST MONDAY
FOR PAZ024>028-056-057-059-063.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...RXR
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1225 PM CST SUN FEB 1 2015
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 948 AM CST SUN FEB 1 2015/
UPDATE...
SHOWERS CONTINUE ACROSS MUCH OF THE MIDSOUTH THIS MORNING. THE
SHOWERS ARE OCCURRING AHEAD OF A LOW PRESSURE SYSTEM AND
ASSOCIATED COLD FRONT. BACK EDGE OF SHOWERS HAVE ALREADY PUSHED
EAST OF RANDOLPH...LAWRENCE...CLAY AND GREENE COUNTIES IN
NORTHEAST ARKANSAS. MODELS INDICATE BACK EDGE WILL BE EAST OF THE
MISSISSIPPI RIVER BY NOON. WILL UPDATE TO TRIM POPS ACCORDINGLY.
STILL CAN/T RULE OUT ISOLATED SHOWERS POPPING UP WEST OF THE RIVER BUT
BULK OF RAIN WILL BE DONE WITH. THINK THE ONLY LOCATIONS WITH
CHANCES OF THUNDER WILL BE ACROSS NORTHEAST MISSISSIPPI AS PRECIP
IS MOVING EAST SO FAST.
MEANWHILE...COLD FRONT HAS JUST PUSHED INTO WESTERN ARKANSAS SO
THERE WILL BE A COUPLE OF HOURS OF NO PRECIP AND WARM AIR
ADVECTION OCCURRING ACROSS NE ARKANSAS THAT WILL NEED TO ALSO BUMP
UP HIGHS TO THE MID 50S.
KRM
DISCUSSION... /ISSUED 430 AM CST SUN FEB 1 2015/
AN ACTIVE WEATHER PATTERN CAN BE EXPECTED FOR THE FIRST WEEK OF
FEBRUARY ACROSS THE MIDSOUTH. EARLY THIS MORNING...SOUTHEAST WINDS
WERE PUSHING MILD AIR INTO THE REGION WITH TEMPERATURES IN SOME
LOCATIONS WARMER THAN THEY WERE DURING THE DAY YESTERDAY. THE
LOWER LEVELS WERE VERY DRY ACROSS MUCH OF THE AREA WITH SURFACE
DEW POINTS IN THE TEENS ALONG THE TN RIVER VALLEY. A WARM FRONT
WAS PUSHING TOWARD THE MIDSOUTH FROM THE SOUTHWEST WITH WIDESPREAD
SHOWERS...THE RAIN WAS HAVING A DIFFICULT TIME REACHING THE GROUND
IN OUR FORECAST AREA WITH THE DRY LOW LEVELS. SURFACE LOW PRESSURE
WAS DEVELOPING OVER THE CENTRAL PLAINS WITH MUCH COLDER AIR
LOCATED ACROSS THE NORTHERN PLAINS PUSHING SOUTHWARD BEHIND THE
LOW.
NOT MUCH CHANGE FROM THE EARLIER FORECAST. AS A UPPER LEVEL TROUGH
DIGS INTO THE MIDDLE MS RIVER VALLEY TODAY...THE SURFACE LOW WILL
STRENGTHEN TO NEAR 1000 MB AND BE LOCATED OVER SOUTHERN IN BY SUNSET.
A COLD FRONT TRAILING SOUTHWESTWARD FROM THE LOW WILL APPROACH
EASTERN AR BY NOON AND MOVE RAPIDLY TO NEAR THE TN RIVER AND THE MS /
AL BORDER BY SUNSET. SHOWERS WILL QUICKLY SPREAD ACROSS THE MIDSOUTH
THIS MORNING AHEAD OF THIS SYSTEM AS UPPER LIFT INCREASES
DRAMATICALLY AND THE LOWER LEVELS BECOME SATURATED. BASED ON THE
FORECAST ELEVATED INSTABILITY...ISOLATED THUNDERSTORMS ARE
EXPECTED ALONG AND SOUTH OF INTERSTATE 40. ALSO...SOME SURFACE BASED
INSTABILITY MAY PUSH INTO NORTH MS DURING THE DAY. THE MODELS
INCLUDING THE HRRR AND RAP ARE SHOWING THE RAIN BEGINNING TO PUSH OUT
OF PORTIONS OF NORTHEAST AR AND PORTIONS OF THE MO BOOTHEEL BY EARLY
AFTERNOON...SO BEGAN TO SHOW THE POPS DECREASING FROM THE WEST AT
THIS TIME.
RAIN IS FORECAST TO QUICKLY END FROM THE WEST EARLY THIS EVENING.
LATEST MODELS ARE NOT SHOWING MUCH IF ANY PRECIP ONCE TEMPERATURES
BECOME COLD ENOUGH FOR SNOW...BUT DID CONTINUE TO MENTION A SLIGHT
CHANCE OF FLURRIES AFTER MIDNIGHT IN ASSOCIATION WITH A TRAILING
UPPER LEVEL TROUGH. OTHERWISE...STRONG AND GUSTY NORTHWEST WINDS
WILL PUSH MUCH COLDER AIR INTO THE AREA WITH WIND CHILL READINGS
DROPPING TO BETWEEN 10 AND 20 DEGREES AFTER MIDNIGHT.
MONDAY WILL BE A VERY COLD DAY AS MODIFIED ARCTIC AIR SETTLES OVER
THE MIDSOUTH. HIGHS WILL ONLY BE IN THE 30S WITH SOME LOCATIONS
NEAR THE MO AND KY BORDERS REMAINING A LITTLE BELOW FREEZING. CLOUDS
ARE EXPECTED TO BEGIN CLEARING BY AFTERNOON. MONDAY NIGHT WILL
SEE LOW TEMPERATURES DIP INTO THE LOWER AND MIDDLE 20S.
HIGH PRESSURE WILL MOVE TO ALONG THE ATLANTIC COAST BY LATE TUESDAY
WITH WINDS TURNING TO THE SOUTH ACROSS THE MIDSOUTH. THIS WILL
ALLOW TEMPERATURES TO WARM TO BETWEEN THE MIDDLE 40S AND LOWER 50S
DURING THE AFTERNOON WITH ABUNDANT SUNSHINE.
ATTENTION TURNS TO OUR THE NEXT WEATHER SYSTEM WEDNESDAY...AN
UPPER LOW OVER TX IN THE SOUTHERN STREAM. THE UPPER LOW IS
FORECAST TO BECOME AN OPEN TROUGH AS IT MOVES INTO THE WESTERN GULF.
SURFACE LOW PRESSURE WILL DEVELOP OVER THE WESTERN GULF WEDNESDAY AS
AN ARCTIC FRONT APPROACHES THE MIDSOUTH FROM THE NORTH LATE IN THE
DAY. LOOKS LIKE THE MIDSOUTH WILL BE BETWEEN THESE TWO SYSTEMS
WEDNESDAY WITH MOST RAIN BEING TO OUR SOUTH ALONG THE NORTHWEST
GULF COAST.
THE WEATHER BECOMES INTERESTING AND COMPLICATED WEDNESDAY NIGHT AND
THURSDAY...ALTHOUGH THE GFS AND ECMWF STILL ARE NOT IN GOOD
AGREEMENT. AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW TO
OUR SOUTH MOVE EASTWARD WITH THE UPPER TROUGH WEAKENING...IT LOOKS
LIKE MOST OF THE RAIN WITH THIS SYSTEM WILL STAY TO OUR SOUTH
POSSIBLY MOVING INTO PORTIONS OF NORTH MS. MEANWHILE...MODELS SHOW
THE ARCTIC FRONT CONTINUING TO PUSH SOUTHWARD THROUGH THE MIDSOUTH.
THE GFS IS FASTER WITH THE COLDER AIR THAN THE ECMWF. SOME LIGHT RAIN
IS INDICATED WITH THIS FRONT WEDNESDAY NIGHT...CHANGING TO LIGHT
SNOW FROM THE NORTH WITH SOME SLEET OR FREEZING POSSIBLE IN THE
TRANSITION ZONE. FOR THURSDAY...THE ECMWF SHOWS THE LIGHT WINTRY
PRECIP MOVING FURTHER SOUTH AS THE ARCTIC FRONT CONTINUES SOUTH...
BUT THE ECMWF QUICKLY MOVES THE PRECIP OUT OF THE AREA BY
AFTERNOON. ON THE OTHER HAND...THE GFS SHOWS A STRONGER UPPER LEVEL
TROUGH FROM THE NORTHWEST INTERACTING WITH THE COLD AIR THURSDAY
WHICH COULD LEAD TO SOME LIGHT SNOW ACCUMULATIONS. FOR NOW...LOTS OF
UNCERTAINTY DURING THIS TIME FRAME. WILL HAVE TO SEE HOW THE MODELS
COME TOGETHER ON THIS SITUATION REGARDING PRECIP IF ANY AND PRECIP
TYPES.
JCL
&&
.AVIATION...
18Z TAF CYCLE
MAINLY IFR CONDS PREVAIL ACROSS THE TERMINALS ATTM AS SHRAS
CONTINUE TO MOVE THROUGH THE AREA IN ADVANCE OF APPROACHING COLD
FRONT. COLD FRONT WILL PUSH THROUGH LATER THIS AFTERNOON AND A FEW
TSRAS ARE POSSIBLE...MAINLY AT KTUP. SHRAS WILL TAPER OFF EARLY
THIS EVENING AND CIGS WILL LIFT TO MVFR...BRIEF VFR POSSIBLE AT
KMEM. GUSTY SOUTH WINDS WILL VEER TO WEST WITH COLD FRONT PASSAGE AND
NW POST FRONTAL...REMAINING GUSTY.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
948 AM CST SUN FEB 1 2015
.UPDATE...
SHOWERS CONTINUE ACROSS MUCH OF THE MIDSOUTH THIS MORNING. THE
SHOWERS ARE OCCURRING AHEAD OF A LOW PRESSURE SYSTEM AND
ASSOCIATED COLD FRONT. BACK EDGE OF SHOWERS HAVE ALREADY PUSHED
EAST OF RANDOLPH...LAWRENCE...CLAY AND GREENE COUNTIES IN
NORTHEAST ARKANSAS. MODELS INDICATE BACK EDGE WILL BE EAST OF THE
MISSISSIPPI RIVER BY NOON. WILL UPDATE TO TRIM POPS ACCORDINGLY.
STILL CAN/T RULE OUT ISOLATED SHOWERS POPPING UP WEST OF THE RIVER BUT
BULK OF RAIN WILL BE DONE WITH. THINK THE ONLY LOCATIONS WITH
CHANCES OF THUNDER WILL BE ACROSS NORTHEAST MISSISSIPPI AS PRECIP
IS MOVING EAST SO FAST.
MEANWHILE...COLD FRONT HAS JUST PUSHED INTO WESTERN ARKANSAS SO
THERE WILL BE A COUPLE OF HOURS OF NO PRECIP AND WARM AIR
ADVECTION OCCURRING ACROSS NE ARKANSAS THAT WILL NEED TO ALSO BUMP
UP HIGHS TO THE MID 50S.
KRM
&&
.DISCUSSION... /ISSUED 430 AM CST SUN FEB 1 2015/
AN ACTIVE WEATHER PATTERN CAN BE EXPECTED FOR THE FIRST WEEK OF
FEBRUARY ACROSS THE MIDSOUTH. EARLY THIS MORNING...SOUTHEAST WINDS
WERE PUSHING MILD AIR INTO THE REGION WITH TEMPERATURES IN SOME
LOCATIONS WARMER THAN THEY WERE DURING THE DAY YESTERDAY. THE
LOWER LEVELS WERE VERY DRY ACROSS MUCH OF THE AREA WITH SURFACE
DEW POINTS IN THE TEENS ALONG THE TN RIVER VALLEY. A WARM FRONT
WAS PUSHING TOWARD THE MIDSOUTH FROM THE SOUTHWEST WITH WIDESPREAD
SHOWERS...THE RAIN WAS HAVING A DIFFICULT TIME REACHING THE GROUND
IN OUR FORECAST AREA WITH THE DRY LOW LEVELS. SURFACE LOW PRESSURE
WAS DEVELOPING OVER THE CENTRAL PLAINS WITH MUCH COLDER AIR
LOCATED ACROSS THE NORTHERN PLAINS PUSHING SOUTHWARD BEHIND THE
LOW.
NOT MUCH CHANGE FROM THE EARLIER FORECAST. AS A UPPER LEVEL TROUGH
DIGS INTO THE MIDDLE MS RIVER VALLEY TODAY...THE SURFACE LOW WILL
STRENGTHEN TO NEAR 1000 MB AND BE LOCATED OVER SOUTHERN IN BY SUNSET.
A COLD FRONT TRAILING SOUTHWESTWARD FROM THE LOW WILL APPROACH
EASTERN AR BY NOON AND MOVE RAPIDLY TO NEAR THE TN RIVER AND THE MS /
AL BORDER BY SUNSET. SHOWERS WILL QUICKLY SPREAD ACROSS THE MIDSOUTH
THIS MORNING AHEAD OF THIS SYSTEM AS UPPER LIFT INCREASES
DRAMATICALLY AND THE LOWER LEVELS BECOME SATURATED. BASED ON THE
FORECAST ELEVATED INSTABILITY...ISOLATED THUNDERSTORMS ARE
EXPECTED ALONG AND SOUTH OF INTERSTATE 40. ALSO...SOME SURFACE BASED
INSTABILITY MAY PUSH INTO NORTH MS DURING THE DAY. THE MODELS
INCLUDING THE HRRR AND RAP ARE SHOWING THE RAIN BEGINNING TO PUSH OUT
OF PORTIONS OF NORTHEAST AR AND PORTIONS OF THE MO BOOTHEEL BY EARLY
AFTERNOON...SO BEGAN TO SHOW THE POPS DECREASING FROM THE WEST AT
THIS TIME.
RAIN IS FORECAST TO QUICKLY END FROM THE WEST EARLY THIS EVENING.
LATEST MODELS ARE NOT SHOWING MUCH IF ANY PRECIP ONCE TEMPERATURES
BECOME COLD ENOUGH FOR SNOW...BUT DID CONTINUE TO MENTION A SLIGHT
CHANCE OF FLURRIES AFTER MIDNIGHT IN ASSOCIATION WITH A TRAILING
UPPER LEVEL TROUGH. OTHERWISE...STRONG AND GUSTY NORTHWEST WINDS
WILL PUSH MUCH COLDER AIR INTO THE AREA WITH WIND CHILL READINGS
DROPPING TO BETWEEN 10 AND 20 DEGREES AFTER MIDNIGHT.
MONDAY WILL BE A VERY COLD DAY AS MODIFIED ARCTIC AIR SETTLES OVER
THE MIDSOUTH. HIGHS WILL ONLY BE IN THE 30S WITH SOME LOCATIONS
NEAR THE MO AND KY BORDERS REMAINING A LITTLE BELOW FREEZING. CLOUDS
ARE EXPECTED TO BEGIN CLEARING BY AFTERNOON. MONDAY NIGHT WILL
SEE LOW TEMPERATURES DIP INTO THE LOWER AND MIDDLE 20S.
HIGH PRESSURE WILL MOVE TO ALONG THE ATLANTIC COAST BY LATE TUESDAY
WITH WINDS TURNING TO THE SOUTH ACROSS THE MIDSOUTH. THIS WILL
ALLOW TEMPERATURES TO WARM TO BETWEEN THE MIDDLE 40S AND LOWER 50S
DURING THE AFTERNOON WITH ABUNDANT SUNSHINE.
ATTENTION TURNS TO OUR THE NEXT WEATHER SYSTEM WEDNESDAY...AN
UPPER LOW OVER TX IN THE SOUTHERN STREAM. THE UPPER LOW IS
FORECAST TO BECOME AN OPEN TROUGH AS IT MOVES INTO THE WESTERN GULF.
SURFACE LOW PRESSURE WILL DEVELOP OVER THE WESTERN GULF WEDNESDAY AS
AN ARCTIC FRONT APPROACHES THE MIDSOUTH FROM THE NORTH LATE IN THE
DAY. LOOKS LIKE THE MIDSOUTH WILL BE BETWEEN THESE TWO SYSTEMS
WEDNESDAY WITH MOST RAIN BEING TO OUR SOUTH ALONG THE NORTHWEST
GULF COAST.
THE WEATHER BECOMES INTERESTING AND COMPLICATED WEDNESDAY NIGHT AND
THURSDAY...ALTHOUGH THE GFS AND ECMWF STILL ARE NOT IN GOOD
AGREEMENT. AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW TO
OUR SOUTH MOVE EASTWARD WITH THE UPPER TROUGH WEAKENING...IT LOOKS
LIKE MOST OF THE RAIN WITH THIS SYSTEM WILL STAY TO OUR SOUTH
POSSIBLY MOVING INTO PORTIONS OF NORTH MS. MEANWHILE...MODELS SHOW
THE ARCTIC FRONT CONTINUING TO PUSH SOUTHWARD THROUGH THE MIDSOUTH.
THE GFS IS FASTER WITH THE COLDER AIR THAN THE ECMWF. SOME LIGHT RAIN
IS INDICATED WITH THIS FRONT WEDNESDAY NIGHT...CHANGING TO LIGHT
SNOW FROM THE NORTH WITH SOME SLEET OR FREEZING POSSIBLE IN THE
TRANSITION ZONE. FOR THURSDAY...THE ECMWF SHOWS THE LIGHT WINTRY
PRECIP MOVING FURTHER SOUTH AS THE ARCTIC FRONT CONTINUES SOUTH...
BUT THE ECMWF QUICKLY MOVES THE PRECIP OUT OF THE AREA BY
AFTERNOON. ON THE OTHER HAND...THE GFS SHOWS A STRONGER UPPER LEVEL
TROUGH FROM THE NORTHWEST INTERACTING WITH THE COLD AIR THURSDAY
WHICH COULD LEAD TO SOME LIGHT SNOW ACCUMULATIONS. FOR NOW...LOTS OF
UNCERTAINTY DURING THIS TIME FRAME. WILL HAVE TO SEE HOW THE MODELS
COME TOGETHER ON THIS SITUATION REGARDING PRECIP IF ANY AND PRECIP
TYPES.
JCL
&&
.AVIATION...
12Z TAF CYCLE
EXPECTING FLIGHT CATEGORIES TO DROP QUICKLY THIS MORNING AS A
BAND OF RAINFALL HAS ALREADY OVERSPREAD JBR AND MEM...MKL AND TUP
SHORTLY. LOOKING AT OBS TO THE WEST...WIDESPREAD IFR CIGS EXIST
WHICH WILL DEVELOP AT JBR AND MEM JUST AFTER 12Z SUNDAY. RAINFALL
COULD BE MODERATE AT TIMES THROUGH ABOUT 21Z AT ALL TAF SITES.
ADDED TEMPO THUNDER AT TUP WHERE SOME INSTABILITY IS FORECAST TO
DEVELOP AHEAD OF THE FRONTAL BOUNDARY. BEST WINDOW FOR THIS LOOKS
TO BE BETWEEN APPROX 20-23Z. WINDS WILL ALSO INCREASE INTO THE
10-15 KT RANGE WITH GUSTS NEAR 18-20 KTS THROUGH THE DAY FROM THE
SOUTH...GRADUALLY VEERING TO SOUTHWEST...THEN WEST-NORTHWESTERLY
BEHIND THE FRONTAL BOUNDARY. LIGHT SHOWERS WILL END FROM WEST TO
EAST SUNDAY NIGHT WITH WINDS REMAINING IN THE 10-15 KT RANGE FROM
THE NORTHWEST. CIGS WILL SLOWLY RISE THROUGH EARLY MONDAY MORNING.
TVT
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
525 AM CST SUN FEB 1 2015
.UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
&&
.PREV DISCUSSION... /ISSUED 430 AM CST SUN FEB 1 2015/
DISCUSSION...
AN ACTIVE WEATHER PATTERN CAN BE EXPECTED FOR THE FIRST WEEK OF
FEBRUARY ACROSS THE MIDSOUTH. EARLY THIS MORNING...SOUTHEAST WINDS
WERE PUSHING MILD AIR INTO THE REGION WITH TEMPERATURES IN
SOME LOCATIONS WARMER THAN THEY WERE DURING THE DAY YESTERDAY. THE
LOWER LEVELS WERE VERY DRY ACROSS MUCH OF THE AREA WITH SURFACE DEW
POINTS IN THE TEENS ALONG THE TN RIVER VALLEY. A WARM FRONT WAS
PUSHING TOWARD THE MIDSOUTH FROM THE SOUTHWEST WITH WIDESPREAD
SHOWERS...THE RAIN WAS HAVING A DIFFICULT TIME REACHING THE GROUND
IN OUR FORECAST AREA WITH THE DRY LOW LEVELS. SURFACE LOW PRESSURE
WAS DEVELOPING OVER THE CENTRAL PLAINS WITH MUCH COLDER AIR LOCATED
ACROSS THE NORTHERN PLAINS PUSHING SOUTHWARD BEHIND THE LOW.
NOT MUCH CHANGE FROM THE EARLIER FORECAST. AS A UPPER LEVEL TROUGH
DIGS INTO THE MIDDLE MS RIVER VALLEY TODAY...THE SURFACE LOW WILL
STRENGTHEN TO NEAR 1000 MB AND BE LOCATED OVER SOUTHERN IN BY SUNSET.
A COLD FRONT TRAILING SOUTHWESTWARD FROM THE LOW WILL APPROACH
EASTERN AR BY NOON AND MOVE RAPIDLY TO NEAR THE TN RIVER AND THE MS /
AL BORDER BY SUNSET. SHOWERS WILL QUICKLY SPREAD ACROSS THE MIDSOUTH
THIS MORNING AHEAD OF THIS SYSTEM AS UPPER LIFT INCREASES
DRAMATICALLY AND THE LOWER LEVELS BECOME SATURATED. BASED ON THE
FORECAST ELEVATED INSTABILITY...ISOLATED THUNDERSTORMS ARE
EXPECTED ALONG AND SOUTH OF INTERSTATE 40. ALSO...SOME SURFACE BASED
INSTABILITY MAY PUSH INTO NORTH MS DURING THE DAY. THE MODELS
INCLUDING THE HRRR AND RAP ARE SHOWING THE RAIN BEGINNING TO PUSH OUT
OF PORTIONS OF NORTHEAST AR AND PORTIONS OF THE MO BOOTHEEL BY EARLY
AFTERNOON...SO BEGAN TO SHOW THE POPS DECREASING FROM THE WEST AT
THIS TIME.
RAIN IS FORECAST TO QUICKLY END FROM THE WEST EARLY THIS EVENING.
LATEST MODELS ARE NOT SHOWING MUCH IF ANY PRECIP ONCE TEMPERATURES
BECOME COLD ENOUGH FOR SNOW...BUT DID CONTINUE TO MENTION A SLIGHT
CHANCE OF FLURRIES AFTER MIDNIGHT IN ASSOCIATION WITH A TRAILING
UPPER LEVEL TROUGH. OTHERWISE...STRONG AND GUSTY NORTHWEST WINDS
WILL PUSH MUCH COLDER AIR INTO THE AREA WITH WIND CHILL READINGS
DROPPING TO BETWEEN 10 AND 20 DEGREES AFTER MIDNIGHT.
MONDAY WILL BE A VERY COLD DAY AS MODIFIED ARCTIC AIR SETTLES OVER
THE MIDSOUTH. HIGHS WILL ONLY BE IN THE 30S WITH SOME LOCATIONS
NEAR THE MO AND KY BORDERS REMAINING A LITTLE BELOW FREEZING. CLOUDS
ARE EXPECTED TO BEGIN CLEARING BY AFTERNOON. MONDAY NIGHT WILL
SEE LOW TEMPERATURES DIP INTO THE LOWER AND MIDDLE 20S.
HIGH PRESSURE WILL MOVE TO ALONG THE ATLANTIC COAST BY LATE TUESDAY
WITH WINDS TURNING TO THE SOUTH ACROSS THE MIDSOUTH. THIS WILL
ALLOW TEMPERATURES TO WARM TO BETWEEN THE MIDDLE 40S AND LOWER 50S
DURING THE AFTERNOON WITH ABUNDANT SUNSHINE.
ATTENTION TURNS TO OUR THE NEXT WEATHER SYSTEM WEDNESDAY...AN
UPPER LOW OVER TX IN THE SOUTHERN STREAM. THE UPPER LOW IS
FORECAST TO BECOME AN OPEN TROUGH AS IT MOVES INTO THE WESTERN GULF.
SURFACE LOW PRESSURE WILL DEVELOP OVER THE WESTERN GULF WEDNESDAY AS
AN ARCTIC FRONT APPROACHES THE MIDSOUTH FROM THE NORTH LATE IN THE
DAY. LOOKS LIKE THE MIDSOUTH WILL BE BETWEEN THESE TWO SYSTEMS
WEDNESDAY WITH MOST RAIN BEING TO OUR SOUTH ALONG THE NORTHWEST
GULF COAST.
THE WEATHER BECOMES INTERESTING AND COMPLICATED WEDNESDAY NIGHT AND
THURSDAY...ALTHOUGH THE GFS AND ECMWF STILL ARE NOT IN GOOD
AGREEMENT. AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW TO
OUR SOUTH MOVE EASTWARD WITH THE UPPER TROUGH WEAKENING...IT LOOKS
LIKE MOST OF THE RAIN WITH THIS SYSTEM WILL STAY TO OUR SOUTH
POSSIBLY MOVING INTO PORTIONS OF NORTH MS. MEANWHILE...MODELS SHOW
THE ARCTIC FRONT CONTINUING TO PUSH SOUTHWARD THROUGH THE MIDSOUTH.
THE GFS IS FASTER WITH THE COLDER AIR THAN THE ECMWF. SOME LIGHT RAIN
IS INDICATED WITH THIS FRONT WEDNESDAY NIGHT...CHANGING TO LIGHT
SNOW FROM THE NORTH WITH SOME SLEET OR FREEZING POSSIBLE IN THE
TRANSITION ZONE. FOR THURSDAY...THE ECMWF SHOWS THE LIGHT WINTRY
PRECIP MOVING FURTHER SOUTH AS THE ARCTIC FRONT CONTINUES SOUTH...
BUT THE ECMWF QUICKLY MOVES THE PRECIP OUT OF THE AREA BY
AFTERNOON. ON THE OTHER HAND...THE GFS SHOWS A STRONGER UPPER LEVEL
TROUGH FROM THE NORTHWEST INTERACTING WITH THE COLD AIR THURSDAY
WHICH COULD LEAD TO SOME LIGHT SNOW ACCUMULATIONS. FOR NOW...LOTS OF
UNCERTAINTY DURING THIS TIME FRAME. WILL HAVE TO SEE HOW THE MODELS
COME TOGETHER ON THIS SITUATION REGARDING PRECIP IF ANY AND PRECIP
TYPES.
JCL
AVIATION...
12Z TAF CYCLE
EXPECTING FLIGHT CATEGORIES TO DROP QUICKLY THIS MORNING AS A
BAND OF RAINFALL HAS ALREADY OVERSPREAD JBR AND MEM...MKL AND TUP
SHORTLY. LOOKING AT OBS TO THE WEST...WIDESPREAD IFR CIGS EXIST
WHICH WILL DEVELOP AT JBR AND MEM JUST AFTER 12Z SUNDAY. RAINFALL
COULD BE MODERATE AT TIMES THROUGH ABOUT 21Z AT ALL TAF SITES.
ADDED TEMPO THUNDER AT TUP WHERE SOME INSTABILITY IS FORECAST TO
DEVELOP AHEAD OF THE FRONTAL BOUNDARY. BEST WINDOW FOR THIS LOOKS
TO BE BETWEEN APPROX 20-23Z. WINDS WILL ALSO INCREASE INTO THE
10-15 KT RANGE WITH GUSTS NEAR 18-20 KTS THROUGH THE DAY FROM THE
SOUTH...GRADUALLY VEERING TO SOUTHWEST...THEN WEST-NORTHWESTERLY
BEHIND THE FRONTAL BOUNDARY. LIGHT SHOWERS WILL END FROM WEST TO
EAST SUNDAY NIGHT WITH WINDS REMAINING IN THE 10-15 KT RANGE FROM
THE NORTHWEST. CIGS WILL SLOWLY RISE THROUGH EARLY MONDAY MORNING.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
430 AM CST SUN FEB 1 2015
.DISCUSSION...
AN ACTIVE WEATHER PATTERN CAN BE EXPECTED FOR THE FIRST WEEK OF
FEBRUARY ACROSS THE MIDSOUTH. EARLY THIS MORNING...SOUTHEAST WINDS
WERE PUSHING MILD AIR INTO THE REGION WITH TEMPERATURES IN
SOME LOCATIONS WARMER THAN THEY WERE DURING THE DAY YESTERDAY. THE
LOWER LEVELS WERE VERY DRY ACROSS MUCH OF THE AREA WITH SURFACE DEW
POINTS IN THE TEENS ALONG THE TN RIVER VALLEY. A WARM FRONT WAS
PUSHING TOWARD THE MIDSOUTH FROM THE SOUTHWEST WITH WIDESPREAD
SHOWERS...THE RAIN WAS HAVING A DIFFICULT TIME REACHING THE GROUND
IN OUR FORECAST AREA WITH THE DRY LOW LEVELS. SURFACE LOW PRESSURE
WAS DEVELOPING OVER THE CENTRAL PLAINS WITH MUCH COLDER AIR LOCATED
ACROSS THE NORTHERN PLAINS PUSHING SOUTHWARD BEHIND THE LOW.
NOT MUCH CHANGE FROM THE EARLIER FORECAST. AS A UPPER LEVEL TROUGH
DIGS INTO THE MIDDLE MS RIVER VALLEY TODAY...THE SURFACE LOW WILL
STRENGTHEN TO NEAR 1000 MB AND BE LOCATED OVER SOUTHERN IN BY SUNSET.
A COLD FRONT TRAILING SOUTHWESTWARD FROM THE LOW WILL APPROACH
EASTERN AR BY NOON AND MOVE RAPIDLY TO NEAR THE TN RIVER AND THE MS /
AL BORDER BY SUNSET. SHOWERS WILL QUICKLY SPREAD ACROSS THE MIDSOUTH
THIS MORNING AHEAD OF THIS SYSTEM AS UPPER LIFT INCREASES
DRAMATICALLY AND THE LOWER LEVELS BECOME SATURATED. BASED ON THE
FORECAST ELEVATED INSTABILITY...ISOLATED THUNDERSTORMS ARE
EXPECTED ALONG AND SOUTH OF INTERSTATE 40. ALSO...SOME SURFACE BASED
INSTABILITY MAY PUSH INTO NORTH MS DURING THE DAY. THE MODELS
INCLUDING THE HRRR AND RAP ARE SHOWING THE RAIN BEGINNING TO PUSH OUT
OF PORTIONS OF NORTHEAST AR AND PORTIONS OF THE MO BOOTHEEL BY EARLY
AFTERNOON...SO BEGAN TO SHOW THE POPS DECREASING FROM THE WEST AT
THIS TIME.
RAIN IS FORECAST TO QUICKLY END FROM THE WEST EARLY THIS EVENING.
LATEST MODELS ARE NOT SHOWING MUCH IF ANY PRECIP ONCE TEMPERATURES
BECOME COLD ENOUGH FOR SNOW...BUT DID CONTINUE TO MENTION A SLIGHT
CHANCE OF FLURRIES AFTER MIDNIGHT IN ASSOCIATION WITH A TRAILING
UPPER LEVEL TROUGH. OTHERWISE...STRONG AND GUSTY NORTHWEST WINDS
WILL PUSH MUCH COLDER AIR INTO THE AREA WITH WIND CHILL READINGS
DROPPING TO BETWEEN 10 AND 20 DEGREES AFTER MIDNIGHT.
MONDAY WILL BE A VERY COLD DAY AS MODIFIED ARCTIC AIR SETTLES OVER
THE MIDSOUTH. HIGHS WILL ONLY BE IN THE 30S WITH SOME LOCATIONS
NEAR THE MO AND KY BORDERS REMAINING A LITTLE BELOW FREEZING. CLOUDS
ARE EXPECTED TO BEGIN CLEARING BY AFTERNOON. MONDAY NIGHT WILL
SEE LOW TEMPERATURES DIP INTO THE LOWER AND MIDDLE 20S.
HIGH PRESSURE WILL MOVE TO ALONG THE ATLANTIC COAST BY LATE TUESDAY
WITH WINDS TURNING TO THE SOUTH ACROSS THE MIDSOUTH. THIS WILL
ALLOW TEMPERATURES TO WARM TO BETWEEN THE MIDDLE 40S AND LOWER 50S
DURING THE AFTERNOON WITH ABUNDANT SUNSHINE.
ATTENTION TURNS TO OUR THE NEXT WEATHER SYSTEM WEDNESDAY...AN
UPPER LOW OVER TX IN THE SOUTHERN STREAM. THE UPPER LOW IS
FORECAST TO BECOME AN OPEN TROUGH AS IT MOVES INTO THE WESTERN GULF.
SURFACE LOW PRESSURE WILL DEVELOP OVER THE WESTERN GULF WEDNESDAY AS
AN ARCTIC FRONT APPROACHES THE MIDSOUTH FROM THE NORTH LATE IN THE
DAY. LOOKS LIKE THE MIDSOUTH WILL BE BETWEEN THESE TWO SYSTEMS
WEDNESDAY WITH MOST RAIN BEING TO OUR SOUTH ALONG THE NORTHWEST
GULF COAST.
THE WEATHER BECOMES INTERESTING AND COMPLICATED WEDNESDAY NIGHT AND
THURSDAY...ALTHOUGH THE GFS AND ECMWF STILL ARE NOT IN GOOD
AGREEMENT. AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW TO
OUR SOUTH MOVE EASTWARD WITH THE UPPER TROUGH WEAKENING...IT LOOKS
LIKE MOST OF THE RAIN WITH THIS SYSTEM WILL STAY TO OUR SOUTH
POSSIBLY MOVING INTO PORTIONS OF NORTH MS. MEANWHILE...MODELS SHOW
THE ARCTIC FRONT CONTINUING TO PUSH SOUTHWARD THROUGH THE MIDSOUTH.
THE GFS IS FASTER WITH THE COLDER AIR THAN THE ECMWF. SOME LIGHT RAIN
IS INDICATED WITH THIS FRONT WEDNESDAY NIGHT...CHANGING TO LIGHT
SNOW FROM THE NORTH WITH SOME SLEET OR FREEZING POSSIBLE IN THE
TRANSITION ZONE. FOR THURSDAY...THE ECMWF SHOWS THE LIGHT WINTRY
PRECIP MOVING FURTHER SOUTH AS THE ARCTIC FRONT CONTINUES SOUTH...
BUT THE ECMWF QUICKLY MOVES THE PRECIP OUT OF THE AREA BY
AFTERNOON. ON THE OTHER HAND...THE GFS SHOWS A STRONGER UPPER LEVEL
TROUGH FROM THE NORTHWEST INTERACTING WITH THE COLD AIR THURSDAY
WHICH COULD LEAD TO SOME LIGHT SNOW ACCUMULATIONS. FOR NOW...LOTS OF
UNCERTAINTY DURING THIS TIME FRAME. WILL HAVE TO SEE HOW THE MODELS
COME TOGETHER ON THIS SITUATION REGARDING PRECIP IF ANY AND PRECIP
TYPES.
JCL
&&
.AVIATION...
06Z TAF CYCLE
DEFINITELY NOT GOOD CONDITIONS FOR FLYING OVER THE NEXT 24 HOURS.
CONDITIONS ARE VFR CURRENTLY AT ALL SITES...BUT DETERIORATING
CONDITIONS ARE EXPECTED TONIGHT...WITH IFR CONDITIONS PREVAILING
TOMORROW. EXPECT CIGS TO LOWER TO IFR BY MID MORNING...01/14Z-01/17Z.
LIGHT SOUTHEAST WINDS WILL VEER SOUTHERLY OVERNIGHT...INCREASE AND
BECOME GUSTY SUNDAY MORNING. SUSTAINED SPEEDS SHOULD BE 10-15KT
WITH GUSTS TO 20KTS. FURTHER VEERING IS EXPECTED TOMORROW
AFTERNOON WHEN SOUTHWEST WINDS ARE EXPECTED. VIS WILL BE MVFR FOR
MOST OF THE DAY TOMORROW DUE TO RAIN. ALTHOUGH THUNDERSTORMS
CANNOT BE RULED OUT...DO NOT FEEL THEY WILL BE NUMEROUS TO INCLUDE
IN TAFS AT THIS TIME. SOME IMPROVEMENT TO CIGS IS POSSIBLE LATE
TOMORROW...NEAR AND AFTER 00Z. HOWEVER GUIDANCE TYPICALLY CLEARS
LOW CLOUDS OUT TOO QUICKLY SO WILL HOLD ONTO LOW CLOUDS THROUGH
THE TAF CYCLE. RAIN SHOULD COME TO AN END FOR JBR BEFORE
00Z...AROUND 00Z AT MEM...AND A COUPLE OF HOURS LATER AT MKL.
WILL KEEP PREVAILING RAIN AT TUP THROUGH 06Z.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
300 PM MST SUN FEB 1 2015
.SYNOPSIS...
A WEAK COLD FRONT HAS MOVED INTO THE AREA AND WILL HELP LOWER
OVERNIGHT TEMPERATURES TONIGHT. AT THE SAME TIME PATCHY FOG IS
EXPECTED TO AGAIN DEVELOP JUST BEFORE SUNRISE THANKS TO LEFT OVER
MOISTURE FROM RECENT RAINS. ONCE THE FOG BURNS OFF MOSTLY SUNNY
CONDITIONS WILL TAKE OVER AND DOMINATE FOR THE REST OF THE WEEK
AHEAD. TEMPS WILL CLIMB TO NEAR NORMAL MONDAY AND SHOULD BE AS MUCH
AS 10 DEGREES ABOVE NORMAL BY THE END OF THE WEEK.
&&
.DISCUSSION...
WITH THE UPPER LOW NOW WELL SOUTH OF THE THE REGION NORTHWESTERLY
FLOW ALOFT HAS TAKEN OVER. A WEAK SHORTWAVE EMBEDDED IN THIS FLOW IS
CURRENTLY PUSHING A WEAK BACK DOOR COLD FRONT THROUGH THE AREA AND
WILL RESULT IN EASTERLY SURFACE FLOW DURING THE OVERNIGHT HOURS.
GIVEN THE FACT THAT THE BOUNDARY LAYER HAS NOT DRIED MUCH IN THE
PAST 24 HOURS...ENOUGH RESIDUAL MOISTURE REMAINS TO HELP GENERATE
ADDITIONAL LOW CLOUDS OVER OUR EASTERN ZONES TONIGHT IN CONJUNCTION
WITH THE UPSLOPE COMPONENT OF THE EASTERLY SURFACE FLOW. IN ADDITION
BOTH THE HI RES WRF AND THE LATEST HRRR SHOW DEW PT DEPRESSIONS
DROPPING TO NEAR ZERO JUST PRIOR TO SUNRISE FOR LOWLAND LOCATIONS OF
SOUTHCENTRAL NEW MEXICO AND FAR WEST TEXAS. IT LOOKS AS IF PATCHY
DENSE FOG WILL FORM ONCE AGAIN IN MANY OF THE SAME AREAS THAT SAW
THE FOG THIS MORNING.
FOG AND LOW CLOUDS SHOULD MIX OUT FAIRLY QUICKLY MONDAY MORNING
AFTER SUNRISE. THIS WILL BE FOLLOWED BY MOSTLY CLEAR SKIES FOR
SEVERAL DAYS TO COME AS RIDGING DEVELOPS ACROSS THE SOUTHWESTERN
STATES. THE END RESULT WILL BE A WARMING TREND THAT SHOULD CARRY
THROUGH MUCH OF THE WEEK AHEAD. A SHORTWAVE WILL ROUND THE RIDGE AND
PASS TO OUR NORTHEAST WEDNESDAY RESULTING IN LEE TROUGHING AND A
SLIGHT UPTICK IN WESTERLY SURFACE WIND SPEEDS. THIS WILL BE FOLLOWED
BY A WEAK BACK DOOR COLD FRONT WEDNESDAY NIGHT. THIS FRONTAL PUSH
WILL ONLY SERVE TO STALL THE WARMING TREND BY ABOUT A DAY OR SO AS
THE RIDGE ALOFT WILL THEN MIGRATE OVERHEAD AS WE APPROACH THE
WEEKEND. IN GENERAL HIGH TEMPS SHOULD RUN A GOOD 10 DEGREES ABOVE
NORMAL BY FRIDAY AND SATURDAY WITH ONLY OCCASIONAL HIGH CLOUDS
PASSING BY.
&&
.AVIATION...VALID 02/00Z-03/00Z...
SATELLITE IMAGERY INDICATES A WEAK BACKDOOR FRONT PUSHING INTO THE
EAST SLOPES OF THE SACRAMENTO MOUNTAINS...DOWN TOWARDS THE EL
PASO/HUDSPETH COUNTY LINE. UPSLOPE LOW CLOUDS/FOG ARE ALREADY IN
PLACE ALONG THE EAST SLOPES OF THE SACRAMENTO MOUNTAINS...AND WILL
LIKELY SPREAD INTO PARTS OF EASTERN HUDSPETH COUNTY LATER TONIGHT.
ELSEWHERE...LIGHT NORTHERLY WINDS WILL BECOME VARIABLE OVERNIGHT
FROM THE TULAROSA BASIN AND ALL POINTS WEST. DEWPOINTS IN THE UPPER
30S TO AROUND 40 INDICATE THAT THE BOUNDARY LAYER HAS NOT MIXED OUT
MUCH OF THE LOW LEVEL MOISTURE TODAY. LACK OF ANY LOW LEVEL DRY
ADVECTION AND IDEAL CONDITIONS FOR RADIATIVE COOLING SUGGEST AREAS
OF FOG WILL RE-DEVELOP AGAIN TOWARDS DAWN. IT IS DIFFICULT TO
PINPOINT THE WORST SPOTS. PORTIONS OF SIERRA COUNTY ARE PERHAPS LESS
FAVORED GIVEN THEY ARE THE RELATIVE DRY SPOT AT THE MOMENT WITH
DEWPOINTS IN THE LOW 30S. VARIOUS MODELS INCLUDING WRF-NMM BROADLY
SUGGEST AN ARC FROM DMN-LRU INTO SOUTHERN SIERRA COUNTY MOST
FAVORED. GENERALLY WENT PESSIMISTIC WITH THE TAFS WITH LIFR VERTICAL
VISBYS AT DMN/LRU. WENT SLIGHTLY DENSER WITH THE FOG (1/4SM IN
TEMPO GROUPS) AT LRU WITH LIGHT SE FLOW POSSIBLE...WHICH FAVORS FOG
ALONG THE WEST MESA. LOW CONFIDENCE FOR ELP AND TCS BUT 1-3SM IN BR
IS POSSIBLE.
OTHERWISE...VFR CONDITIONS AND LIGHT WINDS TO PREVAIL AFTER 18Z.
&&
.FIRE WEATHER...
OBS SHOW LIGHT NORTHERLY WINDS HAVE PUSHED ACROSS MOST OF THE
AREA... WHILE A WEAK BACKDOOR FRONT MOST EVIDENT ON VISIBLE
SATELLITE IMAGERY...IS BRINGING LIGHT EASTERLY WINDS TO THE EAST
SLOPES OF THE SACRAMENTO MOUNTAINS AND PORTIONS OF THE OTERO MESA
AND HUDSPETH COUNTY. THIS WILL RESULT IN SOME UPSLOPE CLOUDS AND FOG
EAST OF THE OTERO MESA RIM AND IN THE SACRAMENTO MOUNTAINS
OVERNIGHT.
ELSEWHERE IN SW NEW MEXICO...MOIST BOUNDARY LAYER CONDITIONS WITH
LACK OF DRY ADVECTION COUPLED WITH WINDS BECOMING LIGHT AND VARIABLE
AFTER MIDNIGHT WILL RESULT IN SOME FOG DEVELOPING AGAIN TOWARDS
DAWN. RH RECOVERY WILL BE EXCELLENT EVEN WITHOUT FOG AS MAX RH
VALUES WILL BE AROUND 80 PERCENT AT THE LOWEST...LIKELY IN PARTS OF
SIERRA COUNTY WHERE BL MIXING WAS MAXIMIZED TODAY.
EXPECT A WARMING/DRYING TREND THROUGH THE WEEK AHEAD. TEMPERATURES
WILL CLIMB TO AROUND 5-8 DEGREES ABOVE AVERAGE BY WEDNESDAY. LIGHT
WINDS AND SHALLOW MIXING WILL LIMIT VENT RATES MONDAY...ESPECIALLY
IN THE LOWLANDS...WITH SOME IMPROVEMENTS ON TUESDAY AND WEDNESDAY
EXCEPT IN THE RIO GRANDE VALLEY.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 35 61 37 65 39 / 0 0 0 0 0
SIERRA BLANCA 34 60 37 63 37 / 0 0 0 0 0
LAS CRUCES 32 58 35 62 37 / 0 0 0 0 0
ALAMOGORDO 30 57 32 61 36 / 0 0 0 0 0
CLOUDCROFT 23 44 26 44 30 / 0 0 0 0 0
TRUTH OR CONSEQUENCES 34 57 37 61 36 / 0 0 0 0 0
SILVER CITY 29 58 34 63 36 / 0 0 0 0 0
DEMING 31 62 32 64 34 / 0 0 0 0 0
LORDSBURG 32 61 33 62 35 / 0 0 0 0 0
WEST EL PASO METRO 38 61 39 66 41 / 0 0 0 0 0
DELL CITY 29 58 32 62 33 / 0 0 0 0 0
FORT HANCOCK 37 63 37 66 38 / 0 0 0 0 0
LOMA LINDA 34 56 35 60 40 / 0 0 0 0 0
FABENS 32 60 35 65 37 / 0 0 0 0 0
SANTA TERESA 33 60 34 64 38 / 0 0 0 0 0
WHITE SANDS HQ 33 59 36 64 39 / 0 0 0 0 0
JORNADA RANGE 28 58 31 61 34 / 0 0 0 0 0
HATCH 30 63 33 67 34 / 0 0 0 0 0
COLUMBUS 34 62 35 63 37 / 0 0 0 0 0
OROGRANDE 33 58 36 64 39 / 0 0 0 0 0
MAYHILL 26 55 32 56 36 / 0 0 0 0 0
MESCALERO 24 50 27 51 32 / 0 0 0 0 0
TIMBERON 28 52 32 52 35 / 0 0 0 0 0
WINSTON 32 54 35 58 34 / 0 0 0 0 0
HILLSBORO 33 57 38 60 39 / 0 0 0 0 0
SPACEPORT 32 60 33 63 36 / 0 0 0 0 0
LAKE ROBERTS 27 57 33 61 34 / 0 0 0 0 0
HURLEY 29 56 33 60 35 / 0 0 0 0 0
CLIFF 27 60 30 62 32 / 0 0 0 0 0
MULE CREEK 23 58 27 61 31 / 0 0 0 0 0
FAYWOOD 33 55 36 60 38 / 0 0 0 0 0
ANIMAS 31 65 32 65 36 / 0 0 0 0 0
HACHITA 29 65 31 65 34 / 0 0 0 0 0
ANTELOPE WELLS 29 65 30 64 34 / 0 0 0 0 0
CLOVERDALE 34 63 33 64 37 / 0 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
LANEY/HARDIMAN
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
357 AM MST SUN FEB 1 2015
.SYNOPSIS...
UPPER LOW OVER THE CENTRAL BAJA PENINSULA WHICH BROUGHT THE LOWLAND
RAIN AND MOUNTAIN SNOW ON SATURDAY...CONTINUES TO DRIFT SOUTHEAST
AND TAKE ANY REMAINING MOISTURE WITH IT. AN UPPER RIDGE WILL BEGIN
BUILDING OVER THE DESERT SOUTHWEST OVER THE NEXT SEVERAL DAYS. THIS
WILL KEEP THE SKIES MOSTLY CLEAR FOR MUCH OF THE UPCOMING WEEK.
TEMPERATURES TODAY WILL STILL BE A BIT BELOW NORMAL BEFORE WARMING
BACK TO NORMAL MONDAY. TUESDAY AND BEYOND...TEMPERATURES WILL
CONTINUE TO WARM MUCH ABOVE NORMAL.
&&
.DISCUSSION...
WINTER STORM SYSTEM ABOUT OVER. DOUBLE LOW FROM YESTERDAY HAS
DEVOLVED INTO SINGLE LOW OVER THE CENTRAL BAJA AS NORTHERN LOW FROM
SATURDAY FILLED IN OVER NORTHERN ARIZONA. IN CONCERT WITH AN UPPER
TROUGH DROPPING DOWN FROM THE NORTH NOW OVER CENTRAL NEW MEXICO...
REMAINING MOISTURE WILL SHEAR OUT TO THE EAST OF THE CWA. WOULDN`T
RULE OUT A FEW SPRINKLES YET THIS MORNING BUT LEFT POPS OUT OF THE
ZONES OTHER THAN EARLY THIS MORNING OVER THE BOOTHEEL...CLOSEST TO
THE UPPER LOW. DENSE FOG WAS A CONCERN AS LOW DEWPOINT DEPRESSIONS
DEVELOPED MOST AREAS WITH THE WET GROUND. HRRR ALSO SHOWED THE LOW
DEPRESSIONS BECOMING WIDESPREAD AFTER 11Z...BUT IN THE END FIGURED
WITH CLOUDS STICKING AROUND THROUGH THE MORNING HOURS WOULD JUST
MENTION FOG IN THE ZONES/GRIDS. ONE OTHER NOTE...MODERATE RAINFALL
OVER THE GILA REGION ON SATURDAY PRODUCED DECENT RISES IN THE GILA
RIVER. THE GILA RIVER AT VIRDEN ACTUALLY BRIEFLY TOPPED ACTION STAGE
BUT IS FORECAST TO QUICKLY DROP TODAY. ALL OTHER GILA RIVER GAGES
REMAINED BELOW ACTION STAGE.
OTHERWISE UPPER RIDGE WILL BUILD IN OVER THE DESERT SOUTHWEST TODAY
AND MONDAY. THIS SHOULD KEEP LOWER CLOUDS OUT ALTHOUGH SOME PATCHES
OF HIGHER CLOUDS WILL PUSH THROUGH...ESPECIALLY WITH OLD WEAKENED
PACIFIC FRONT ALOFT ON WEDNESDAY AND AGAIN ON FRIDAY. WEAK BACK DOOR
COLD FRONT MOVES IN ON THURSDAY AS UPPER TROUGH RUNS DOWN THE FRONT
SIDE OF THE RIDGE. NOT MUCH COLD ADVECTION WITH THIS BUT ENOUGH TO
STUNT THE WARMING FOR A DAY. TEMPERATURES WILL CLIMB TO NEAR NORMAL
MONDAY AND THEN TO MUCH ABOVE NORMAL THE REST OF THE WEEK. BY NEXT
SATURDAY AND SUNDAY LOWLAND TEMPS COULD TOP 70 DEGREES.
&&
.AVIATION...VALID 01/12Z-02/12Z...
CONDITIONS MOSTLY VFR NOW WITH SCT/BKN100 WITH FEW LAYERS TO 250.
EXPECT PATCHY IFR FOG TO DEVELOP AT THIS TIME...WITH VISIBILITIES OF
ONE-QUARTER TO ONE MILE. CONDITIONS DISSIPATING AFTER 17Z. CLOUDS
DECREASING AFTER 20Z.
&&
.FIRE WEATHER...
UPPER LOW NOW WELL SOUTH OF THE AREA AND TAKING MOST OF THE CLOUDS
OFF TO OUR EAST THIS MORNING. SOME PATCHY FOG MAY DEVELOP THROUGH
MID MORNING. MIN RH`S TODAY WILL BE IN THE 50S AND DECREASING TO THE
40S BY TUESDAY. OTHERWISE THE NEXT 5 TO 7 DAYS LOOKS VERY
UNEVENTFUL...WITH VERY FEW CLOUDS AND TEMPERATURES WARMING BACK TO
ABOVE NORMAL BY MONDAY AND BEYOND. BY THE END OF THE WEEK HIGH TEMPS
COULD BE AROUND 10 DEGREES ABOVE NORMAL.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 57 34 61 37 65 / 0 0 0 0 0
SIERRA BLANCA 55 31 59 35 63 / 0 0 0 0 0
LAS CRUCES 56 32 59 35 64 / 0 0 0 0 0
ALAMOGORDO 56 30 57 33 62 / 0 0 0 0 0
CLOUDCROFT 40 22 45 27 48 / 0 0 0 0 0
TRUTH OR CONSEQUENCES 54 33 58 34 62 / 0 0 0 0 0
SILVER CITY 51 31 54 33 60 / 0 0 0 0 0
DEMING 57 31 60 33 64 / 0 0 0 0 0
LORDSBURG 57 30 60 33 63 / 10 0 0 0 0
WEST EL PASO METRO 59 35 61 39 65 / 0 0 0 0 0
DELL CITY 55 29 60 32 64 / 0 0 0 0 0
FORT HANCOCK 56 35 61 37 64 / 0 0 0 0 0
LOMA LINDA 52 31 55 35 59 / 0 0 0 0 0
FABENS 57 33 60 35 64 / 0 0 0 0 0
SANTA TERESA 57 32 60 35 64 / 0 0 0 0 0
WHITE SANDS HQ 57 34 59 35 63 / 0 0 0 0 0
JORNADA RANGE 56 29 58 32 63 / 0 0 0 0 0
HATCH 59 32 62 33 65 / 0 0 0 0 0
COLUMBUS 58 35 60 36 63 / 0 0 0 0 0
OROGRANDE 56 32 59 35 63 / 0 0 0 0 0
MAYHILL 45 26 52 33 58 / 0 0 0 0 0
MESCALERO 46 24 48 28 53 / 0 0 0 0 0
TIMBERON 47 27 50 33 55 / 0 0 0 0 0
WINSTON 49 29 54 32 57 / 0 0 0 0 0
HILLSBORO 52 33 55 35 60 / 0 0 0 0 0
SPACEPORT 56 31 59 34 64 / 0 0 0 0 0
LAKE ROBERTS 51 29 54 31 58 / 0 0 0 0 0
HURLEY 53 31 55 31 60 / 0 0 0 0 0
CLIFF 55 25 57 22 63 / 0 0 0 0 0
MULE CREEK 52 22 56 19 60 / 0 0 0 0 0
FAYWOOD 53 33 55 34 60 / 0 0 0 0 0
ANIMAS 58 30 62 33 65 / 10 0 0 0 0
HACHITA 58 31 61 32 66 / 0 0 0 0 0
ANTELOPE WELLS 58 30 62 31 66 / 0 0 0 0 0
CLOVERDALE 54 32 60 33 63 / 10 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
17/99
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1115 PM CST SAT JAN 31 2015
.AVIATION...
/06Z TAFS/
Most West Central TX forecast terminals are reporting MVFR
ceilings as of 05z, but conditions should deteriorate overnight
with most areas dropping into IFR (with ceilings under 1000 ft).
Scattered showers will affect KSJT, KABI, and KSOA early this
morning, but confidence is too low to mention elsewhere.
Otherwise, expect patchy fog/drizzle to restrict visibilities at
times. Winds will veer to the southwest late tonight, shifting to
the north as a cold front moves across the area during the late
morning and early afternoon hours. Winds will be gusty through
around 00z, eventually subsiding after sunset. Ceilings will
rapidly improve behind this front with VFR conditions expected
areawide by mid- afternoon.
Johnson
&&
.PREV DISCUSSION... /ISSUED 917 PM CST SAT JAN 31 2015/
UPDATE...
Updated the grids and zones to go with chance POPS across the
entire area tonight. Also, a few thunderstorms are possible
across the Northern Edwards Plateau.
PREV DISCUSSION... /ISSUED 638 PM CST Sat Jan 31 2015/
AVIATION...
/00Z TAFS/
Ceilings remain below 1500 ft across most of West Central TX, with
many forecast terminals experiencing IFR (or worse) conditions.
The primary rain shield has moved east of the forecast area.
However, isentropic ascent will ramp up overnight, resulting in
lowering ceilings and potential light precipitation, mainly in the
form of drizzle. This will knock cloud bases down to generally
700 ft or lower and should cause prevailing visibilities to drop
to 5 miles or less. Some locations may experience more significant
reductions in visibility. Expect poor flight conditions overnight
but winds will veer to the southwest overnight ahead of a cold
front. This front will move through the Big Country mid/late
morning, bringing drier air into the area and eroding the low
clouds from north to south throughout the day. Gusty north winds
will prevail in the wake of this front.
PREV DISCUSSION... /ISSUED 351 PM CST SAT JAN 31 2015/
SHORT TERM...
(Tonight and Sunday )
Light rain was moving north of I-20, and east of an Abilene...
Brady...Mason line at 3 PM. An upper low was west of El Paso,
moving slowly southeast.
Rain was pushing east and ending of West Central, faster than the
models indicated. Indeed at the current pace, nearly all the
present rain at 3 PM will be east or north of West Central Texas
by 6 PM. Kept a chance of showers going overnight, however, with
the El Paso low sending weak disturbances eastward. Additional
rainfall amounts will be light...ranging from a trace to a few
hundredths inch. The NAM and EC models bring isolated to scattered
light showers over West Central Texas tonight. The GFS model`s
convective algorithm is dry. The short range HRRR model brings in
scattered showers, mainly over Crockett county, the Concho Valley
and areas southward. Timing was between 9 PM and 4 AM. This may
actually be the best model as it seems to latched on an area of
lift in the water vapor loop south of El Paso.
A cold front will move through West Central Texas Sunday bringing
gusty north winds by noon. This clear low level moisture and
clouds. Sunshine in the afternoon should allow afternoon highs to
be a 2-4 degrees warmer than today`s, despite cold air advection.
LONG TERM...
(Sunday night through next Saturday)
Warmer weather will make a return to West Central Texas for the
first half of the week. An area of high pressure centered over the
region on Monday, will slide off to our east by mid-week. A
thermal ridge at 850 mb will expand east over the area, allowing
high temperatures to climb from the mid 50s on Monday, to the mid
60s by Wednesday. A weak cold front approaching the area from the
north Wednesday night, will wash out near Interstate 10 during the
day Thursday, bringing cooler/drier air to the region. However,
this will be short-lived, as a lee trough develops to our west on
Friday. With a return flow developing, warmer temperatures and
increasing moisture are expected.
Precipitation chances may also increase for the southern half of
the forecast area. An upper-level disturbance currently located
over Baja California, is expected to pass by to our southeast
Tuesday night/Wednesday morning. This system may bring a chance of
rain to the region, mainly south of a line from San Angelo to
Brownwood. This afternoon`s numerical models have once again
shifted the track of the disturbance farther south and east,
reducing forecast confidence. However, the models have been flip-
flopping on the track for the last few model runs, and considering
the system is still largely in a data-void region, this will
likely continue through the next 48 hours. By then, the system
will enter an improving observational/upper-air network, which may
result in improved model continuity. Given the concerns mentioned
above, only minimal changes were made to the rainfall forecast for
the middle of the week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 49 51 24 51 36 / 40 10 5 5 5
San Angelo 51 60 27 54 36 / 30 10 5 5 5
Junction 52 64 30 55 34 / 40 20 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
505 PM CST SUN FEB 1 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 220 PM CST SUN FEB 1 2015
CONCERNS THROUGH MONDAY...
1. DIMINISHING SNOW/BLOWING SNOW THROUGH THE EVENING
2. NEED FOR WIND CHILL ADVISORY LATE TONIGHT/MONDAY MORNING
3. HIGHS MONDAY
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S....A SHORTWAVE TOPPING THE RIDGE
COMING INTO BRITISH COLUMBIA...A DEEP TROUGH OVER THE CENTRAL PLAINS
INTO SOUTHERN PORTIONS OF THE FORECAST AREA...AND A SHORTWAVE OVER
THE EASTERN DAKOTAS. MID-LEVEL FRONTOGENESIS ASSOCIATED ON THE NORTH
SIDE OF THE DEEP TROUGH CONTINUES TO BRING SNOW TO THE SOUTHEASTERN
2/3 OF THE FORECAST AREA. OVER THE NORTHWEST 1/3 AND THROUGH THE
REST OF MINNESOTA AND NORTHERN WI...DRIER AND COLDER AIR CONTINUES
TO ADVECT SOUTHWARD ON A BRISK NORTHERLY BREEZE. NUMEROUS SITES
NORTH OF I-94 REPORTING SURFACE DEWPOINTS BELOW ZERO...AND AS MUCH
AS 20 BELOW IN NORTHERN MN. TEMPERATURES TOO WERE IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO NORTH OF I-94. CLEARING SKIES REFLECT
THE DRIER...COLDER AIR. MAIN 1004MB SURFACE LOW ASSOCIATED WITH THE
TROUGH WELL TO OUR SOUTHEAST...JUST EAST OF LINCOLN IL. HOWEVER...A
TIGHT PRESSURE GRADIENT EXISTS NORTH OF THIS LOW KEEPING THE BRISK
NORTH BREEZE GOING...WITH A 1034MB HIGH OVER THE DAKOTAS.
THE SNOW REMAINS ON TRACK TO DIMINISH NORTHWEST TO SOUTHEAST THROUGH
THE REST OF THIS AFTERNOON INTO EARLY THIS EVENING. BY 00Z...GOOD
MODEL AGREEMENT EXISTS FOR SNOW SOUTHEAST OF A LINE FROM OELWEIN TO
TOMAH...AND THEN OUT OF THE FORECAST AREA BY 03Z. ALTHOUGH SNOW IS
DIMINISHING...WINDS LOOK TO REMAIN BRISK THROUGH AT LEAST A GOOD
PORTION OF THE EVENING. 925MB WINDS AT 00Z RANGE FROM 25-35KT...
DROPPING TO 10-25KT AT 06Z. THESE GUSTY WINDS SHOULD KEEP
SOME BLOWING AND DRIFTING SNOW GOING AT EXPOSED LOCATIONS...EVEN
WHEN THE SNOW ENDS...THUS HAVE DECIDED TO HOLD OFF CANCEL ANY
HAZARDS AT THIS TIME. HOWEVER...ITS POSSIBLE SOME AREAS MAY
GET CANCELLED EARLY OVER THE NEXT FEW HOURS SEEING DODGE CENTER HAS
IMPROVED TO 10 MILE VISIBILITY ALREADY.
DURING THE OVERNIGHT HOURS...THE SHORTWAVE CURRENTLY IN THE EASTERN
DAKOTAS IS PROGGED TO CROSS THE FORECAST AREA. ALTHOUGH NO
PRECIPITATION PRODUCTION IS EXPECTED WITH THIS SHORTWAVE DUE TO
PLENTIFUL DRY AIR AROUND AND AHEAD OF IT...THE SHORTWAVE WILL HELP
TO BRING THE DAKOTAS SURFACE RIDGE INTO THE FORECAST
AREA...THUS DIMINISHING THE WINDS AND CLEARING THE SKIES OUT. WITH
THE FRESH SNOW COVER...TEMPERATURES COULD REALLY PLUMMET...AIDED TOO
BY 925MB TEMPS FALLING TO -16 TO -18C. WOULD NOT BE SURPRISED TO SEE
A FEW READINGS OF 10 BELOW...WHICH WOULD MOST LIKELY OCCUR NEAR
AUSTIN MN AND IN TAYLOR COUNTY WI. DESPITE THE COLD READINGS...WIND
CHILLS SHOULD STAY UP JUST ABOVE THE -20F THRESHOLD FOR AN ADVISORY.
A MUCH QUIETER BUT COLD DAY ON TAP FOR MONDAY AS THE SURFACE RIDGE
CROSSES THE FORECAST AREA. THE SURFACE RIDGE GRADUALLY CROSSES THE
FORECAST AREA...WITH MOSTLY SUNNY SKIES TO START. SHOULD SEE SOME
INCREASE IN CLOUDS IN THE AFTERNOON AS THE SHORTWAVE COMING INTO
BRITISH COLUMBIA DROPS DOWN INTO THE SIOUX FALLS AREA BY 00Z. 925MB
TEMPS DONT START WARMING UNTIL LATE IN THE DAY...AND WITH FRESH
SNOW...HIGHS ONLY LOOK TO TOP OUT IN THE LOW TO MID TEENS. ITS
POSSIBLE SOME LOCATIONS IN NORTHEAST IOWA ONLY REACH THE SINGLE
DIGITS ABOVE ZERO AS SUGGESTED BY THE 01.12Z ECMWF/CANADIAN.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 220 PM CST SUN FEB 1 2015
LONG TERM CONCERNS...
1. BRIEF LIGHT SNOW MAKER MONDAY EVENING FOR MAINLY NORTHEAST IOWA
2. ANOTHER LIGHT SNOW MAKER FOR TUESDAY AFTERNOON/EVENING...MAINLY
SOUTH OF I-90
3. POSSIBLE WIND CHILL ADVISORY FOR THURSDAY MORNING
4. POSSIBILITY FOR A BRIEF WARM UP...BUT BREEZY...FOR FRIDAY INTO
SATURDAY.
SHORTWAVE OVER BRITISH COLUMBIA IS PROGGED TO DIG INTO SOUTHEAST
IOWA AND NORTHEAST MO BY 06Z TUESDAY. THIS TRACK HAS TRENDED
SOUTHWEST SLIGHTLY OVER THE PAST FEW DAYS. DESPITE ITS POTENT
NATURE/LOOK...MODELS DO NOT PRODUCE MUCH QPF WITH IT DUE TO
DRY AIR IN PLACE FROM MONDAY...WITH THE GFS ENTIRELY DRY. GIVEN ITS
STRENGTH FEEL THE NEED TO INCLUDE A LOW PRECIPITATION CHANCE FOR
MONDAY EVENING...SIMILAR TO THE PREVIOUS FORECAST. HOWEVER...WITH
THE SOUTHWEST TREND IN THE GUIDANCE...SHIFTED THE CHANCES A LITTLE
MORE SOUTHWEST AS WELL. SHOULD ANY SNOW OCCUR...MAYBE A FEW TENTHS
ACCUMULATE.
AFTER A QUIET OVERNIGHT MONDAY NIGHT INTO TUESDAY MORNING...POSSIBLY
A BIT COOL WITH A SURFACE RIDGE CROSSING...ANOTHER SHORTWAVE TROUGH
COMING TROUGH NORTHWEST FLOW IS PROGGED TO AFFECT THE AREA TUESDAY
AFTERNOON AND EVENING. THIS SHORTWAVE...ALTHOUGH WEAKER
COMPARED TO THE PREVIOUS ONE...HAS A LITTLE MORE MOISTURE TO WORK
WITH AND A STRONGER MID LEVEL FRONTOGENESIS ZONE. AS SUCH...01.12Z
NAM/GFS/ECMWF/CANADIAN ALL DEVELOP PRECIPITATION...WITH SOME EVEN
SHOWING POTENTIAL TO EXCEED 0.10 OF QPF IN 6 HOURS. SOME
TRACK ISSUES AGAIN EXIST...WITH THE STRONGEST CONSENSUS FOR THE SNOW
TO MOVE THROUGH LOCATIONS SOUTH OF I-90. UNLESS THE SHORTWAVE
BECOMES STRONGER IN LATER RUNS...FEEL THE PLACEMENT OF THIS SNOW
SHOULD STAY PERSISTENT. THUS...DID RAISE PRECIPITATION CHANCES
TOWARDS 50 ACROSS NORTHEAST IA/FAR SOUTHWEST WI. MAY END UP
ACCUMULATING 1-2 INCHES. SOME CONCERN TOO FOR THE PRECIPITATION TO
END AS FREEZING DRIZZLE AS ICE IS LOST ALOFT...BUT ITS VERY
POSSIBLE THE PRECIPITATION ENDS TOO ONCE WE LOSE THE ICE.
THEREFORE...HAVE YET TO INTRODUCE THIS INTO THE FORECAST.
SOMETHING TO MONITOR.
A STRONG UPPER TROUGH DROPS INTO THE REGION ON WEDNESDAY. THERE
COULD BE A LITTLE LIGHT SNOW IN OUR SOUTH DURING THE AFTERNOON WITH
ANOTHER FRONTOGENESIS BAND SETTING UP ACROSS IOWA AND ILLINOIS.
HOWEVER...THE MORE SIGNIFICANT PART IS THE ARCTIC AIR ACCOMPANY THE
UPPER TROUGH. 925MB TEMPS PLUMMET FROM -10 TO -13C AT 12Z WEDNESDAY
TO -18 TO -20C AT 12Z THURSDAY. A SOMEWHAT BRISK NORTHERLY BREEZE IS
PROGGED WEDNESDAY AFTERNOON AND EVENING BEFORE DIMINISHING
OVERNIGHT. THIS DIMINISHING COULD KEEP US JUST OUT OF A WIND CHILL
ADVISORY NEED FOR THURSDAY MORNING...BUT TEMPERATURES WOULD TANK
INSTEAD...ESPECIALLY IF SKIES ARE CLEAR. STAYED ON THE COOLER SIDE
OF GUIDANCE FOR LOWS WEDNESDAY NIGHT GIVEN THIS REGIME AND
THINKING ARCTIC AIR COMING IN WILL CLEAR SKIES OUT.
THE UPPER TROUGH IS FAST MOVING SUCH THAT WEAK UPPER RIDGING COMES
IN BY THURSDAY AFTERNOON...WITH NORTHWEST FLOW PERSISTING BEYOND
INTO SUNDAY. THUS...AFTER THE COLD START THURSDAY MORNING WE WILL BE
ON THE WARMING TREND HEADING INTO FRIDAY AND SATURDAY. STILL A LOT
OF SPREAD AMONGST ECMWF GUIDANCE REGARDING THE HIGHS FRIDAY AND
SATURDAY...BUT GENERAL TREND SHOULD BRING HIGHS BACK TO NORMAL.
GFS/ECMWF 925MB WINDS ALSO INCREASE TO 20-40KT ON FRIDAY...THUS
SUGGESTING IT COULD BE A BIT BREEZY. SOMETHING WELL HAVE TO WATCH
HEADING INTO NEXT WEEKEND IS A FRONTOGENETIC ZONE DROPPING SOUTHWEST
THROUGH THE FORECAST AREA. ACTUAL POSITION AND TIMING HAS VARIED
SOMEWHAT...REQUIRING LOW CHANCES OF PRECIPITATION THROUGH THE
WEEKEND. NEVERTHELESS...COULD SEE A COUPLE INCHES OF SNOW
ACCUMULATION. COOLER AIR FOLLOWS IN THE WAKE OF THIS ZONE FOR
SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 505 PM CST SUN FEB 1 2015
THE SNOW HAS SHIFTED EAST OF KRST/KLSE AT EARLY EVENING...WITH
LATEST OBS INDICATING THAT BLSN IS BECOMING LESS OF A CONCERN AT
KRST. CIGS HAVE ALREADY IMPROVED TO VFR AT THE TAF SITES TOO...AND
EXPECT VFR CONDITIONS TO PREVAIL TONIGHT THROUGH MONDAY.
WINDS WILL BE ON A DECREASING TREND THIS EVENING AS THE LOW EXITS
EAST...HIGH PRESSURE APPROACHES...AND THE PRESSURE GRADIENT
SLACKENS. VARIABLE WINDS IN THE MORNING WILL BECOME SOUTHERLY BY
18Z MONDAY.
UPPER LEVEL SHORTWAVE TROUGH SLATED TO SPIN ACROSS IOWA MONDAY
NIGHT...LIKELY BRINGING A LITTLE LIGHT SNOW. CURRENT TRACK WOULD
KEEP THE BULK OF ANY -SN SOUTHWEST OF KRST/KLSE...BUT WOULD BRING AT
LEAST SOME LOW/MID LEVEL CIGS. MVFR IS POSSIBLE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR WIZ054-061.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
WIZ041>044-053-055.
MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
MNZ086>088-094>096.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
220 PM CST SUN FEB 1 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 220 PM CST SUN FEB 1 2015
CONCERNS THROUGH MONDAY...
1. DIMINISHING SNOW/BLOWING SNOW THROUGH THE EVENING
2. NEED FOR WIND CHILL ADVISORY LATE TONIGHT/MONDAY MORNING
3. HIGHS MONDAY
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S....A SHORTWAVE TOPPING THE RIDGE
COMING INTO BRITISH COLUMBIA...A DEEP TROUGH OVER THE CENTRAL PLAINS
INTO SOUTHERN PORTIONS OF THE FORECAST AREA...AND A SHORTWAVE OVER
THE EASTERN DAKOTAS. MID-LEVEL FRONTOGENESIS ASSOCIATED ON THE NORTH
SIDE OF THE DEEP TROUGH CONTINUES TO BRING SNOW TO THE SOUTHEASTERN
2/3 OF THE FORECAST AREA. OVER THE NORTHWEST 1/3 AND THROUGH THE
REST OF MINNESOTA AND NORTHERN WI...DRIER AND COLDER AIR CONTINUES
TO ADVECT SOUTHWARD ON A BRISK NORTHERLY BREEZE. NUMEROUS SITES
NORTH OF I-94 REPORTING SURFACE DEWPOINTS BELOW ZERO...AND AS MUCH
AS 20 BELOW IN NORTHERN MN. TEMPERATURES TOO WERE IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO NORTH OF I-94. CLEARING SKIES REFLECT
THE DRIER...COLDER AIR. MAIN 1004MB SURFACE LOW ASSOCIATED WITH THE
TROUGH WELL TO OUR SOUTHEAST...JUST EAST OF LINCOLN IL. HOWEVER...A
TIGHT PRESSURE GRADIENT EXISTS NORTH OF THIS LOW KEEPING THE BRISK
NORTH BREEZE GOING...WITH A 1034MB HIGH OVER THE DAKOTAS.
THE SNOW REMAINS ON TRACK TO DIMINISH NORTHWEST TO SOUTHEAST THROUGH
THE REST OF THIS AFTERNOON INTO EARLY THIS EVENING. BY 00Z...GOOD
MODEL AGREEMENT EXISTS FOR SNOW SOUTHEAST OF A LINE FROM OELWEIN TO
TOMAH...AND THEN OUT OF THE FORECAST AREA BY 03Z. ALTHOUGH SNOW IS
DIMINISHING...WINDS LOOK TO REMAIN BRISK THROUGH AT LEAST A GOOD
PORTION OF THE EVENING. 925MB WINDS AT 00Z RANGE FROM 25-35KT...
DROPPING TO 10-25KT AT 06Z. THESE GUSTY WINDS SHOULD KEEP
SOME BLOWING AND DRIFTING SNOW GOING AT EXPOSED LOCATIONS...EVEN
WHEN THE SNOW ENDS...THUS HAVE DECIDED TO HOLD OFF CANCEL ANY
HAZARDS AT THIS TIME. HOWEVER...ITS POSSIBLE SOME AREAS MAY
GET CANCELLED EARLY OVER THE NEXT FEW HOURS SEEING DODGE CENTER HAS
IMPROVED TO 10 MILE VISIBILITY ALREADY.
DURING THE OVERNIGHT HOURS...THE SHORTWAVE CURRENTLY IN THE EASTERN
DAKOTAS IS PROGGED TO CROSS THE FORECAST AREA. ALTHOUGH NO
PRECIPITATION PRODUCTION IS EXPECTED WITH THIS SHORTWAVE DUE TO
PLENTIFUL DRY AIR AROUND AND AHEAD OF IT...THE SHORTWAVE WILL HELP
TO BRING THE DAKOTAS SURFACE RIDGE INTO THE FORECAST
AREA...THUS DIMINISHING THE WINDS AND CLEARING THE SKIES OUT. WITH
THE FRESH SNOW COVER...TEMPERATURES COULD REALLY PLUMMET...AIDED TOO
BY 925MB TEMPS FALLING TO -16 TO -18C. WOULD NOT BE SURPRISED TO SEE
A FEW READINGS OF 10 BELOW...WHICH WOULD MOST LIKELY OCCUR NEAR
AUSTIN MN AND IN TAYLOR COUNTY WI. DESPITE THE COLD READINGS...WIND
CHILLS SHOULD STAY UP JUST ABOVE THE -20F THRESHOLD FOR AN ADVISORY.
A MUCH QUIETER BUT COLD DAY ON TAP FOR MONDAY AS THE SURFACE RIDGE
CROSSES THE FORECAST AREA. THE SURFACE RIDGE GRADUALLY CROSSES THE
FORECAST AREA...WITH MOSTLY SUNNY SKIES TO START. SHOULD SEE SOME
INCREASE IN CLOUDS IN THE AFTERNOON AS THE SHORTWAVE COMING INTO
BRITISH COLUMBIA DROPS DOWN INTO THE SIOUX FALLS AREA BY 00Z. 925MB
TEMPS DONT START WARMING UNTIL LATE IN THE DAY...AND WITH FRESH
SNOW...HIGHS ONLY LOOK TO TOP OUT IN THE LOW TO MID TEENS. ITS
POSSIBLE SOME LOCATIONS IN NORTHEAST IOWA ONLY REACH THE SINGLE
DIGITS ABOVE ZERO AS SUGGESTED BY THE 01.12Z ECMWF/CANADIAN.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 220 PM CST SUN FEB 1 2015
LONG TERM CONCERNS...
1. BRIEF LIGHT SNOW MAKER MONDAY EVENING FOR MAINLY NORTHEAST IOWA
2. ANOTHER LIGHT SNOW MAKER FOR TUESDAY AFTERNOON/EVENING...MAINLY
SOUTH OF I-90
3. POSSIBLE WIND CHILL ADVISORY FOR THURSDAY MORNING
4. POSSIBILITY FOR A BRIEF WARM UP...BUT BREEZY...FOR FRIDAY INTO
SATURDAY.
SHORTWAVE OVER BRITISH COLUMBIA IS PROGGED TO DIG INTO SOUTHEAST
IOWA AND NORTHEAST MO BY 06Z TUESDAY. THIS TRACK HAS TRENDED
SOUTHWEST SLIGHTLY OVER THE PAST FEW DAYS. DESPITE ITS POTENT
NATURE/LOOK...MODELS DO NOT PRODUCE MUCH QPF WITH IT DUE TO
DRY AIR IN PLACE FROM MONDAY...WITH THE GFS ENTIRELY DRY. GIVEN ITS
STRENGTH FEEL THE NEED TO INCLUDE A LOW PRECIPITATION CHANCE FOR
MONDAY EVENING...SIMILAR TO THE PREVIOUS FORECAST. HOWEVER...WITH
THE SOUTHWEST TREND IN THE GUIDANCE...SHIFTED THE CHANCES A LITTLE
MORE SOUTHWEST AS WELL. SHOULD ANY SNOW OCCUR...MAYBE A FEW TENTHS
ACCUMULATE.
AFTER A QUIET OVERNIGHT MONDAY NIGHT INTO TUESDAY MORNING...POSSIBLY
A BIT COOL WITH A SURFACE RIDGE CROSSING...ANOTHER SHORTWAVE TROUGH
COMING TROUGH NORTHWEST FLOW IS PROGGED TO AFFECT THE AREA TUESDAY
AFTERNOON AND EVENING. THIS SHORTWAVE...ALTHOUGH WEAKER
COMPARED TO THE PREVIOUS ONE...HAS A LITTLE MORE MOISTURE TO WORK
WITH AND A STRONGER MID LEVEL FRONTOGENESIS ZONE. AS SUCH...01.12Z
NAM/GFS/ECMWF/CANADIAN ALL DEVELOP PRECIPITATION...WITH SOME EVEN
SHOWING POTENTIAL TO EXCEED 0.10 OF QPF IN 6 HOURS. SOME
TRACK ISSUES AGAIN EXIST...WITH THE STRONGEST CONSENSUS FOR THE SNOW
TO MOVE THROUGH LOCATIONS SOUTH OF I-90. UNLESS THE SHORTWAVE
BECOMES STRONGER IN LATER RUNS...FEEL THE PLACEMENT OF THIS SNOW
SHOULD STAY PERSISTENT. THUS...DID RAISE PRECIPITATION CHANCES
TOWARDS 50 ACROSS NORTHEAST IA/FAR SOUTHWEST WI. MAY END UP
ACCUMULATING 1-2 INCHES. SOME CONCERN TOO FOR THE PRECIPITATION TO
END AS FREEZING DRIZZLE AS ICE IS LOST ALOFT...BUT ITS VERY
POSSIBLE THE PRECIPITATION ENDS TOO ONCE WE LOSE THE ICE.
THEREFORE...HAVE YET TO INTRODUCE THIS INTO THE FORECAST.
SOMETHING TO MONITOR.
A STRONG UPPER TROUGH DROPS INTO THE REGION ON WEDNESDAY. THERE
COULD BE A LITTLE LIGHT SNOW IN OUR SOUTH DURING THE AFTERNOON WITH
ANOTHER FRONTOGENESIS BAND SETTING UP ACROSS IOWA AND ILLINOIS.
HOWEVER...THE MORE SIGNIFICANT PART IS THE ARCTIC AIR ACCOMPANY THE
UPPER TROUGH. 925MB TEMPS PLUMMET FROM -10 TO -13C AT 12Z WEDNESDAY
TO -18 TO -20C AT 12Z THURSDAY. A SOMEWHAT BRISK NORTHERLY BREEZE IS
PROGGED WEDNESDAY AFTERNOON AND EVENING BEFORE DIMINISHING
OVERNIGHT. THIS DIMINISHING COULD KEEP US JUST OUT OF A WIND CHILL
ADVISORY NEED FOR THURSDAY MORNING...BUT TEMPERATURES WOULD TANK
INSTEAD...ESPECIALLY IF SKIES ARE CLEAR. STAYED ON THE COOLER SIDE
OF GUIDANCE FOR LOWS WEDNESDAY NIGHT GIVEN THIS REGIME AND
THINKING ARCTIC AIR COMING IN WILL CLEAR SKIES OUT.
THE UPPER TROUGH IS FAST MOVING SUCH THAT WEAK UPPER RIDGING COMES
IN BY THURSDAY AFTERNOON...WITH NORTHWEST FLOW PERSISTING BEYOND
INTO SUNDAY. THUS...AFTER THE COLD START THURSDAY MORNING WE WILL BE
ON THE WARMING TREND HEADING INTO FRIDAY AND SATURDAY. STILL A LOT
OF SPREAD AMONGST ECMWF GUIDANCE REGARDING THE HIGHS FRIDAY AND
SATURDAY...BUT GENERAL TREND SHOULD BRING HIGHS BACK TO NORMAL.
GFS/ECMWF 925MB WINDS ALSO INCREASE TO 20-40KT ON FRIDAY...THUS
SUGGESTING IT COULD BE A BIT BREEZY. SOMETHING WELL HAVE TO WATCH
HEADING INTO NEXT WEEKEND IS A FRONTOGENETIC ZONE DROPPING SOUTHWEST
THROUGH THE FORECAST AREA. ACTUAL POSITION AND TIMING HAS VARIED
SOMEWHAT...REQUIRING LOW CHANCES OF PRECIPITATION THROUGH THE
WEEKEND. NEVERTHELESS...COULD SEE A COUPLE INCHES OF SNOW
ACCUMULATION. COOLER AIR FOLLOWS IN THE WAKE OF THIS ZONE FOR
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1137 AM CST SUN FEB 1 2015
MESO MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THE SNOW WILL END AT
BOTH TAF SITES BETWEEN 01.20Z AND 01.21Z. AT THE SAME TIME...THE
WIND GUSTS WILL BE DECREASING INTO THE 20 TO 30 KNOT RANGE. THE
WINDS WILL CONTINUE TO DECREASE RAPIDLY THIS EVENING AS THE
SURFACE PRESSURE GRADIENT RELAXES. MVRF CLOUDS WILL PERSIST INTO
THE EVENING...AND THEN QUICKLY DISSIPATE BETWEEN 02.03Z AND
02.06Z. SKIES WILL REMAIN MAINLY CLEAR THROUGH THE 02.18Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR WIZ054-061.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
WIZ041>044-053-055.
MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
MNZ086>088-094>096.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 AM CST SUN FEB 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN FEB 1 2015
CHALLENGES THIS MORNING INCLUDE SNOW AMOUNTS AND ASSOCIATED
HEADLINES. 01.00Z MODELS ARE IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION.
CALLS TO LAW ENFORCEMENT EARLY THIS MORNING REVEALED 4 TO 5 INCHES
IN OSAGE AND 3 TO 4 INCHES IN DECORAH. FURTHER NORTH ALONG THE
I-90 CORRIDOR FROM ROCHESTER TO LA CROSSE...1 TO 2 INCHES IS
RELATIVELY COMMON. LATEST RAP SHOWS A MODEST BAND OF 850 HPA
FRONTOGENESIS RE-DEVELOPING ALONG THE MN/IA BORDER LATER THIS
MORNING. THIS LOWER LEVEL FORCING COMBINED WITH INCREASING
Q-VECTOR CONVERGENCE IN THE 500 TO 300 HPA LAYER ASSOCIATED WITH
THE APPROACHING CANADIAN TROUGH WILL RESULT IN 6-12 MORE HOURS OF
LIGHT SNOW ACROSS THE UPPER MS RIVER VALLEY.
LATEST REPORTS...MODEL/COBB DATA AND RADAR TRENDS PROVIDE ENOUGH
EVIDENCE TO JUSTIFY SOME CHANGES TO CURRENT HEADLINES. WILL EXTEND
THE WINTER STORM WARNING A TIER OF COUNTIES NORTHWARD FROM
MITCHELL TO CRAWFORD WHERE 6 TO 9 INCHES STORM TOTAL SNOW WILL
FALL. TO THE NORTH...WILL EXPAND THE WINTER WEATHER ADVISORY TO
INCLUDE THE I-90 CORRIDOR FROM OLMSTED TO JUNEAU/ADAMS COUNTIES
WHERE 3 TO 5 TOTAL INCHES ARE EXPECTED. FOR BOTH AREAS...THERE IS
LIKELY TO BE A SHARP GRADIENT IN SNOW AMOUNTS FROM NORTH TO SOUTH.
ALSO EXPECT AREAS OF BLOWING AND DRIFTING SNOW...ESPECIALLY ACROSS
WIND PRONE AREAS OF SOUTHEAST MN AND NORTHEAST IA GIVEN 30 TO 35
KTS AT THE TOP OF THE MIXED BOUNDARY LAYER. TRAVEL WILL REMAIN
DIFFICULT IF NOT HAZARDOUS FOR MUCH OF THE DAY.
ACCUMULATING SNOWFALL WILL QUICKLY TAPER OFF TO NOTHING NORTH OF
HIGHWAY 10 GIVEN VERY DRY AIRMASS ACROSS NORTHERN WI/MN WITH
SURFACE DEW POINTS DROPPING INTO THE TEENS TO LOWER 20S BELOW ZERO
ALONG THE CANADIAN BORDER. SNOW WILL SLOWLY DIMINISH AND MOVE OUT
OF THE REGION FROM NORTHWEST TO SOUTHEAST LATER THIS AFTERNOON.
TODAY WILL BE MARKEDLY COOLER WITH TEMPERATURES TOPPING OUT IN THE
TEENS...BUT WITH A STIFF NORTHERLY WIND...EXPECT WIND CHILL VALUES
IN THE SINGLE DIGITS BELOW ZERO. COLD CONDITIONS TO PERSIST
OVERNIGHT WITH CLEARING SKIES ALLOWING AIR TEMPERATURES TO DROP
BELOW ZERO. NORTHERLY WINDS FROM 5 TO 10 MPH WILL RESULT IN WIND
CHILLS FROM 10 TO 20 BELOW ZERO BY MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN FEB 1 2015
TEMPERATURES TO REMAIN AT OR BELOW EARLY FEBRUARY NORMALS THROUGH
THE UPCOMING WORK WEEK WITH DAILY HIGHS FROM THE MID TEENS TO MID
20S AND LOWS FROM THE SINGLE DIGITS BELOW AND ABOVE ZERO.
AFTER A DRY MONDAY...SNOW CHANCES RETURN MONDAY NIGHT THROUGH
MID-WEEK AND THEN AGAIN BY EARLY NEXT WEEKEND. CONFIDENCE IN
STRENGTH AND TIMING OF THE RESPONSIBLE SHORT-WAVES IN NORTHWEST
FLOW ALOFT ARE AVERAGE AT BEST. GIVEN OVERALL DRIER AIR PARCEL
SOURCE REGION...SNOW ACCUMULATIONS THROUGH THE WEEK APPEAR TO BE
RELATIVELY MINOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1137 AM CST SUN FEB 1 2015
MESO MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THE SNOW WILL END AT
BOTH TAF SITES BETWEEN 01.20Z AND 01.21Z. AT THE SAME TIME...THE
WIND GUSTS WILL BE DECREASING INTO THE 20 TO 30 KNOT RANGE. THE
WINDS WILL CONTINUE TO DECREASE RAPIDLY THIS EVENING AS THE
SURFACE PRESSURE GRADIENT RELAXES. MVRF CLOUDS WILL PERSIST INTO
THE EVENING...AND THEN QUICKLY DISSIPATE BETWEEN 02.03Z AND
02.06Z. SKIES WILL REMAIN MAINLY CLEAR THROUGH THE 02.18Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR WIZ054-061.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
WIZ041>044-053-055.
MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
MNZ086>088-094>096.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
323 AM CST SUN FEB 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN FEB 1 2015
CHALLENGES THIS MORNING INCLUDE SNOW AMOUNTS AND ASSOCIATED
HEADLINES. 01.00Z MODELS ARE IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION.
CALLS TO LAW ENFORCEMENT EARLY THIS MORNING REVEALED 4 TO 5 INCHES
IN OSAGE AND 3 TO 4 INCHES IN DECORAH. FURTHER NORTH ALONG THE
I-90 CORRIDOR FROM ROCHESTER TO LA CROSSE...1 TO 2 INCHES IS
RELATIVELY COMMON. LATEST RAP SHOWS A MODEST BAND OF 850 HPA
FRONTOGENESIS RE-DEVELOPING ALONG THE MN/IA BORDER LATER THIS
MORNING. THIS LOWER LEVEL FORCING COMBINED WITH INCREASING
Q-VECTOR CONVERGENCE IN THE 500 TO 300 HPA LAYER ASSOCIATED WITH
THE APPROACHING CANADIAN TROUGH WILL RESULT IN 6-12 MORE HOURS OF
LIGHT SNOW ACROSS THE UPPER MS RIVER VALLEY.
LATEST REPORTS...MODEL/COBB DATA AND RADAR TRENDS PROVIDE ENOUGH
EVIDENCE TO JUSTIFY SOME CHANGES TO CURRENT HEADLINES. WILL EXTEND
THE WINTER STORM WARNING A TIER OF COUNTIES NORTHWARD FROM
MITCHELL TO CRAWFORD WHERE 6 TO 9 INCHES STORM TOTAL SNOW WILL
FALL. TO THE NORTH...WILL EXPAND THE WINTER WEATHER ADVISORY TO
INCLUDE THE I-90 CORRIDOR FROM OLMSTED TO JUNEAU/ADAMS COUNTIES
WHERE 3 TO 5 TOTAL INCHES ARE EXPECTED. FOR BOTH AREAS...THERE IS
LIKELY TO BE A SHARP GRADIENT IN SNOW AMOUNTS FROM NORTH TO SOUTH.
ALSO EXPECT AREAS OF BLOWING AND DRIFTING SNOW...ESPECIALLY ACROSS
WIND PRONE AREAS OF SOUTHEAST MN AND NORTHEAST IA GIVEN 30 TO 35
KTS AT THE TOP OF THE MIXED BOUNDARY LAYER. TRAVEL WILL REMAIN
DIFFICULT IF NOT HAZARDOUS FOR MUCH OF THE DAY.
ACCUMULATING SNOWFALL WILL QUICKLY TAPER OFF TO NOTHING NORTH OF
HIGHWAY 10 GIVEN VERY DRY AIRMASS ACROSS NORTHERN WI/MN WITH
SURFACE DEW POINTS DROPPING INTO THE TEENS TO LOWER 20S BELOW ZERO
ALONG THE CANADIAN BORDER. SNOW WILL SLOWLY DIMINISH AND MOVE OUT
OF THE REGION FROM NORTHWEST TO SOUTHEAST LATER THIS AFTERNOON.
TODAY WILL BE MARKEDLY COOLER WITH TEMPERATURES TOPPING OUT IN THE
TEENS...BUT WITH A STIFF NORTHERLY WIND...EXPECT WIND CHILL VALUES
IN THE SINGLE DIGITS BELOW ZERO. COLD CONDITIONS TO PERSIST
OVERNIGHT WITH CLEARING SKIES ALLOWING AIR TEMPERATURES TO DROP
BELOW ZERO. NORTHERLY WINDS FROM 5 TO 10 MPH WILL RESULT IN WIND
CHILLS FROM 10 TO 20 BELOW ZERO BY MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN FEB 1 2015
TEMPERATURES TO REMAIN AT OR BELOW EARLY FEBRUARY NORMALS THROUGH
THE UPCOMING WORK WEEK WITH DAILY HIGHS FROM THE MID TEENS TO MID
20S AND LOWS FROM THE SINGLE DIGITS BELOW AND ABOVE ZERO.
AFTER A DRY MONDAY...SNOW CHANCES RETURN MONDAY NIGHT THROUGH
MID-WEEK AND THEN AGAIN BY EARLY NEXT WEEKEND. CONFIDENCE IN
STRENGTH AND TIMING OF THE RESPONSIBLE SHORT-WAVES IN NORTHWEST
FLOW ALOFT ARE AVERAGE AT BEST. GIVEN OVERALL DRIER AIR PARCEL
SOURCE REGION...SNOW ACCUMULATIONS THROUGH THE WEEK APPEAR TO BE
RELATIVELY MINOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1100 PM CST SAT JAN 31 2015
SNOW HAS MOVED IN WITH DROPPING CIGS AND VSBYS. EXPECT KRST/KLSE TO
HOVER IN THE 1-2SM RANGE MOST OF THE TIME...WITH SOME DIP TO 1/2-
3/4SM AT KRST FROM TIME TO TIME. CIGS SHOULD HOLD NEAR 1 KFT...KRST
MOSTLY BELOW AND KLSE MOSTLY ABOVE.
THE BULK OF THE HEAVIER SNOWS WILL FALL THROUGH MID MORNING
SUNDAY...WITH GRADUAL IMPROVEMENT THROUGH THE REST OF THE DAY.
AMOUNTS NEAR 4 INCHES APPEAR LIKELY AT THIS TIME.
INCREASING PRESSURE GRADIENT WILL RESULT IN INCREASING WINDS/GUST
OVERNIGHT...PERSISTING INTO SUNDAY AFTERNOON. COULD BE SOME BLSN AT
KRST AS A RESULT...LIKELY CONTINUING SOME VSBY RESTRICTIONS EVEN
WHEN ACCUM SNOWS HAVE STOPPED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR WIZ061.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
WIZ053>055.
MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
MNZ094>096.
IA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR IAZ018-019-
029-030.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR
IAZ008>011.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CARIBOU ME
111 AM EST TUE FEB 3 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF NOVA SCOTIA OVERNIGHT. HIGH
PRESSURE WILL CROSS THE REGION TUESDAY. LOW PRESSURE WILL CROSS
THE REGION WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
100 AM UPDATE: WE CANX WNTR WX HDLNS OVR THE WRN PTN OF THE FA
THIS UPDATE WITH STEADY SN NOW SLOWLY MOVG E INTO NB PROV. WE WILL
LIKELY CANX THE REST OF THE WNTR WX HDLNS THE NEXT UPDATE...AT
WHICH POINT WE WILL DETERMINE WHAT PTN OF THE FA NEEDS WIND CHILL
HDLNS AFT WE UPDATE WINDS. OTHERWISE...FCST HRLY TEMPS THRU THE
REST OF THE NGT INTO TUE MORN WERE MODIFIED BASED ON TRENDS SEEN
FROM MDNGT OBS.
PREV DISC: 00Z SURFACE ANALYSIS HAD 985MB LOW MOVING TOWARD THE
SE TIP OF NOVA SCOTIA. HEAVIER BANDING STILL OCCURRING ON THE NW
SIDE OF THE STORM W/SOME HEAVY SNOWFALL OCCURRING ACROSS PORTIONS
OF EASTERN MAINE INCLUDING WASHINGTON COUNTY. RECEIVED REPORTS OF
12-16 INCHES ACROSS THE DOWNEAST INCLUDING THE COAST. AS ONE
TRAVELS NORTH, REPORTS SHOW 6-9 INCHES W/UP TO 6 INCHES IN SE
AROOSTOOK COUNT. EARLIER REPORTS OF 1-2 INCHES PER HOUR ESPECIALLY
IN THE BANGOR AND BAR HARBOR REGION. BANDING HAS SHIFTED E OF THE
BANGOR AND BAR HARBOR AND THE LATEST TREND FROM THE RAP AND NAM12
INDICATE THINGS TO WIND DOWN FROM SW TO NE OVER THE NEXT 2 TO 4
HRS. WILL KEEP CURRENT HEADLINES IN PLACE TO COVER FOR THE GUSTY
WINDS AND HAZARDOUS TRAVEL EXPECTED.
PARTIAL CLEARING TUESDAY MORNING AS HIGH PRESSURE PUSHES INTO THE
AREA. SOME CLOUDS WILL THEN INCREASE LATE IN THE DAY AS A WEAK
SHORTWAVE APPROACHES FROM THE WEST.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION TUESDAY NIGHT
WITH PARTLY/MOSTLY CLOUDY SKIES. LOW PRESSURE WILL APPROACH FROM
THE SOUTHWEST WEDNESDAY WITH INCREASING LIGHT SNOW CHANCES DURING
THE AFTERNOON. SNOW ACCUMULATIONS WEDNESDAY AFTERNOON WILL BE
LESS THAN AN INCH. THE LOW WILL CROSS THE REGION WEDNESDAY NIGHT
WITH ADDITIONAL LIGHT SNOW ACCUMULATIONS POSSIBLE MOSTLY
EARLY...WITH THE SNOW THEN TAPERING TO SNOW SHOWERS OVERNIGHT.
UNCERTAINTY THEN INCREASES THURSDAY REGARDING WHETHER HIGH
PRESSURE WILL BUILD ACROSS THE REGION OR WHETHER LOW PRESSURE
COULD BEGIN TO LIFT NORTH ALONG THE COAST. DUE TO THIS UNCERTAINTY
HAVE KEPT ONLY A CHANCE OF SNOW SHOWERS THURSDAY. HOWEVER...IF THE
DEVELOPING LOW SCENARIO IS CORRECT A STEADIER ACCUMULATING SNOW
WILL DEVELOP THURSDAY. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS
WEDNESDAY/THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MAIN CONCERN IN THE EXTENDED IS POTENTIAL FOR ANOTHER MAJOR STORM
AROUND THURSDAY NIGHT. HOWEVER, VERY LITTLE CONFIDENCE AT THIS
POINT. OPERATIONAL GFS AND CANADIAN MODEL AND MOST (BUT NOT ALL)
OF THEIR ENSEMBLES SEND THE WEDNESDAY TO EARLY THURSDAY SYSTEM FAR
ENOUGH OFFSHORE TO WHERE ANY LOW PRESSURE DEVELOPMENT ALONG THE
FRONT IS TOO FAR EAST TO IMPACT MAINE. HOWEVER, 0Z UKMET AND 0/12Z
ECMWF MODELS HANG THE ARCTIC FRONT JUST OFFSHORE WITH A NOR`EASTER
DEVELOPING ALONG THE FRONT IN RESPONSE TO A VIGOROUS SHORTWAVE
DIGGING SOUTHEAST FROM THE GREAT LAKES. HARD TO RECONCILE THE
DIFFERENCES...HIGH PRESSURE AND CLEAR VS LOW PRESSURE AND SNOWY
LATE THURSDAY INTO FRIDAY. AM QUITE HESITANT TO LEAN EITHER WAY AT
THIS POINT AND WENT WITH A CONSENSUS APPROACH. WILL BE EXTREMELY
INTERESTING TO WATCH MODEL TRENDS OVER THE NEXT DAY.
THE IMPACT OF AN ADDITIONAL POTENTIAL STORM WOULD BE VERY SIGNIFICANT
ESPECIALLY CONSIDERING THE EXTREME RECENT SNOWFALL. EASTPORT
RECEIVED 57.9 INCHES OF SNOW IN THE EIGHT DAYS FROM JAN 25 TO FEB
1, WITH ANOTHER 16 OR SO INCHES ON THE WAY TODAY INTO TONIGHT. THE
MACHIAS COOP OBSERVER`S 46.1 INCHES OF SNOW IN AN 8 DAY PERIOD
SHATTERS THAT COOP STATION`S 8-DAY RECORD OF 33.5 INCHES FROM
1964. RECORDS AT MACHIAS GO BACK TO 1893. THE EASTPORT 57.9 INCHES
IS FROM A COCORAHS OBSERVER, BUT A RECENTLY DECOMMISSIONED COOP
SITE IN EASTPORT HAS AN 8 DAY SNOWFALL RECORD OF 33 INCHES WITH
RECORDS FROM 1895 TO 2013, SO THE 57.9 INCHES WOULD SHATTER THAT.
BANGOR HAS HAD 31.4 INCHES IN THE 8 DAY PERIOD, WHICH IS NUMBER 3
FOR THEM, WITH THE RECORD 8 DAY SNOWFALL BEING 37 INCHES IN 1972.
SOUTHERN PORTIONS OF THE AREA ESPECIALLY ARE ALREADY HAVING A VERY
MEMORABLE PERIOD OF WEATHER WHICH IS GETTING MORE MEMORABLE BY THE
MOMENT WITH THE CURRENT STORM. I WOULD SAY THE CURRENT MONDAY STORM
IS PUSHING DOWNEAST MAINE TO THE LIMIT, NOT TO MENTION ANOTHER
POTENTIAL STORM AFTER THIS ONE.
THE MODEL DISAGREEMENTS CONTINUE INTO THE WEEKEND. GFS/CANADIAN
HAVE A FAIRLY WEAK CLIPPER SYSTEM SATURDAY AND SATURDAY NIGHT
WHILE THE ECMWF IS JUST COLD AND DRY. EITHER WAY, SUNDAY INTO
EARLY NEXT WEEK LOOK COLDER THAN NORMAL, NOT THAT IS HASN`T BEEN
COLDER THAN NORMAL ALREADY AS OF LATE. CANNOT TOTALLY RULE OUT
STORMINESS PERSISTING INTO EARLY NEXT WEEK, BUT MODELS ARE IN
EXTREMELY POOR AGREEMENT SO HESITANT TO SAY MUCH AT THIS POINT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR CONDITIONS IN SNOW TONIGHT WILL IMPROVE TO MVFR
LATE THIS EVENING THEN VFR LATE TONIGHT. VFR CONDITIONS ARE
EXPECTED ON TUESDAY.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT. CONDITIONS
WILL THEN LOWER TO MVFR/IFR LEVELS WEDNESDAY...WITH SIMILAR
CONDITIONS PERSISTING INTO WEDNESDAY NIGHT. CONDITIONS THURSDAY
INTO SATURDAY WILL BE DEPENDENT ON WHETHER HIGH PRESSURE IS ABLE
TO BUILD ACROSS THE REGION OR WHETHER LOW PRESSURE LIFTS NORTH
ACROSS THE FORECAST AREA WHICH IS UNCERTAIN AT THIS TIME.
&&
.MARINE...
NEAR TERM: A GALE WARNING IS UP FOR THE WATERS INTO TUESDAY
MORNING. ALSO, A HEAVY FREEZING SPRAY WARNING WILL BE ISSUED FOR
HEAVY FREEZING SPRAY TONIGHT INTO EARLY TUESDAY MORNING AS
DEPARTING LOW PRESSURE PULLS BITTERLY COLD AIR OVER THE WATERS ON
GUSTY NORTH TO NORTHWEST WINDS. WINDS WILL DIMINISH TUESDAY
AFTERNOON.
SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TUESDAY
NIGHT THROUGH THURSDAY. VISIBILITIES WILL BE REDUCED IN SNOW
WEDNESDAY INTO WEDNESDAY NIGHT WITH A CHANCE OF SNOW SHOWERS
THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
MEZ002.
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR MEZ001-
003.
WINTER STORM WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR
MEZ005-006-011-017-030-032.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 8 AM EST THIS MORNING FOR
ANZ050>052.
GALE WARNING UNTIL 9 AM EST THIS MORNING FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...FOISY
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
444 AM EST TUE FEB 3 2015
.SYNOPSIS...
A FAST MOVING CLIPPER SYSTEM WILL BRING LIGHT SNOW TUESDAY NIGHT
INTO EARLY WEDNESDAY MAINLY NORTH OF PITTSBURGH. A COLD FRONT
WEDNESDAY WILL BRING ANOTHER ROUND OF LIGHT SNOW AND MUCH
REINFORCE THE COLD AIR.
&&
.NEAR TERM /THROUGH TONIGHT/...
TEMPERATURES CONTINUE THEIR DOWNWARD TREND WITH SKIES MOSTLY
CLEARING AND WINDS DISSIPATING. STILL HAVENT COMPLETELY CALMED THE
WINDS AT THIS HOUR...SO TEMPS HAVE NOT BOTTOMED OUT. COLDEST
READINGS THUS FAR ARE NORTH OF I-80 WITH WIND CHILLS DIPPING INTO
THE SINGLE DIGITS BELOW ZERO. SOUTH OF PITTSBURGH...THE
TEMPERATURES HAVE NOT FALLEN AS DRAMATICALLY AS RESIDUAL CLOUDS
AND AN OLDER/RAGGED SNOWPACK HAS KEEP SLOWED THE COOLING. STILL
EXPECTING TEMPS EVERYWHERE TO GET INTO THE SINGLE DIGITS BEFORE DAYBREAK.
SOMEWHAT COMPLICATED FORECAST FOR TODAY AS THERE WILL BE A MIX OF
RESIDUAL LLVL MOISTURE AND HIGH CLOUDS STREAMING IN FROM THE WEST.
THE RAP IS BULLISH ON BRINGING LOW TO MID STRATUS DECK CURRENTLY
OVER SRN WV/KY BACK NORTH INTO OUR AREA. NOT BUYING INTO THIS SOLN
AS DRIER AND WARMER AIR SHOULD HELP EAT AWAY THIS CLOUD DECK AS
THE LLVL FLOW BACKS TO THE SOUTHWEST. THE RESULTANT SKY COVER IS
ON THE OPTIMISTIC SIDE...AHEAD OF THE NEXT SYSTEM THAT WILL
INCREASE CLOUDS TONIGHT.
A QUICK ALBERTA CLIPPER WILL DROP ACROSS THE NRN PLAINS TODAY
STREAMING THROUGH THE WRN GREAT LAKES THIS EVENING. SFC LOW
DEEPENS AS IT PASSES JUST NORTH OF LAKE ERIE TONIGHT. TEMPS
TONIGHT WILL STAY RELATIVELY STABLE THROUGH AS WAA INCREASES AHEAD
OF THE AXIS OF THE MID-LEVEL TROF. DESPITE THE WAA...TEMPS WILL
STAY LOW ENOUGH THAT SNOW WILL BE THE P-TYPE EVERYWHERE THAT
PRECIPITATION IS GENERATED. WITH A LACK OF A SRLY MOISTURE FEED
INTO THE LOW...THE SYSTEM OVERALL IS RELATIVELY MOISTURE
STARVED...KEEPING MOST OF THE SNOW CLOSER TO THE LOW. MODEL
CONSENSUS IS THAT TRACK STAYING JUST NORTH OF LAKE
ERIE...ULTIMATELY KEEPING THE BEST SNOW POTENTIAL IN OUR AREA
NORTH OF I-80. THOSE AREAS SHOULD SEE AN INCH OR TWO TOTAL
ACCUMULATION THROUGH DAY BREAK WEDS. ELSEWHERE...LESS THAN AN
INCH IS EXPECTED.
TAX
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
SFC LOW ASSOCIATED WITH THE MID-WEEK CLIPPER QUICKLY MOVES OFF TO
THE NORTHEAST...BUT A LONG TRAILING COLD FRONT WILL USHER IN MORE
SNOW FOLLOWED BY MUCH COLDER TEMPERATURES TOWARDS THE END OF THE
SHORT TERM. STARTING FROM NEAR NORMAL LOWS WEDS MORNING STRONG WAA
WILL CONTINUE TO PUSH TEMPERATURES UP INTO THE 30S AND IN SOME CASES
LOW 40S. A LULL IN PRECIPITATION CHANCES OCCURS WEDS IN THE
QUASI-WARM SECTOR BETWEEN THE DEPARTING CLIPPER AND BEFORE THE COLD
FRONT MOVES IN.
THE COLD FRONT ARRIVES IN THE FORECAST AREA BY LATE WEDS
EVENING...DROPPING TEMPERATURES QUICKLY THROUGH THE NIGHT INTO THE
TEENS. STRONG WARMING AHEAD OF THE FRONT AND COPIOUS CAA BEHIND WILL
AMPLIFY THE TROF AND STRENGTHEN THE FRONT ON ARRIVAL. EVERYONE WILL
RECEIVE SNOW AS THE FRONT CROSSES...THE ONLY QUESTION IS HOW MUCH.
WPC QPF SEEMS RATHER HIGH AT THIS POINT GIVEN THE LACK OF STRONG
OUTSIDE MOISTURE FEED AND THE CONTINENTAL ORIGIN OF THE INCOMING
AIRMASS. WITH THIS IN MIND...WPC QPF WAS CUT WITH A BLEND OF
GFS/SREF WHICH KNOCKS THE ORIGINAL DOWN BY HALF. SNOW RATIOS SHOULD
START OUT NEAR 10:1...WHICH GIVES EVERYONE AN 1-2" WITH THE INITIAL
FRONTAL PASSAGE.
THE POST-FRONTAL AIRMASS IS EXTREMELY COLD AND WILL KEEP THURS HIGH
TEMPS SUPPRESSED IN THE TEENS. 850MB TEMPS DROP TO NEAR -20C BY
MIDDAY THURS STEEPENING LAPSE RATES AIDING THE GENERATION OF
CONVECTIVELY DRIVEN SNOW SHOWERS. SNOW RATIOS WILL GROW IN THE
POST-FRONTAL SNOW SHOWERS AS THE DENDRITIC GROWTH ZONE COMES
CRASHING DOWN TO THE LLVLS. BY THE TIME ALL IS SAID AND DONE...SNOW
TOTALS COULD APPROACH ADVISORY LEVELS. WILL INSERT MENTION OF THIS
IN HWO FOR NOW.
TAX
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DRY CONDITIONS AND A WARMING TREND CAN BE EXPECTED FRIDAY AND SATURDAY
AS HIGH PRESSURE BUILDS IN ACROSS THE REGION. THAT BEING
SAID...FRIDAY MORNING MIN TEMPERATURES WILL BE VERY COLD AS CLOUD
COVERAGE SCATTERS OUT AFTER A GOOD DEAL OF STRONG COLD AIR
ADVECTION OVER THE COURSE OF THE DAY ON THURSDAY BEHIND A
LOW PRESSURE SYSTEM EXITING TO THE EAST. MINIMUM TEMPERATURES ARE
FORECAST AROUND ZERO DEGREES ON AVERAGE ON FRIDAY MORNING...AND
AFTER TAKING A MIDDLE OF THE ROAD APPROACH IN REGARDS TO WIND
SPEEDS...THERE IS DEFINITELY POTENTIAL THAT APPARENT TEMPERATURES
WILL MEET/EXCEED ADVISORY CRITERIA FRIDAY MORNING. BROAD UPPER
TROUGHING SETS UP OVER THE EASTERN STATES THE REMAINDER OF THE
WEEKEND AND INTO EARLY NEXT WEEK. THE CURRENT EXTENDED FORECAST
WAS BASED LARGELY ON ENSEMBLE GUIDANCE AS OPERATIONAL MODELS
CONTINUE TO SHOW LARGER THAN AVERAGE SPREAD IN THE EXTENDED.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED THROUGH THE DAY AS HIGH PRESSURE
TRANSITIONS ACROSS THE AREA. OVERNIGHT AND INTO WEDNESDAY MORNING A
QUICK MOVING SYSTEM WILL BRUSH BY TO THE NORTH WITH LOCATIONS
NORTH OF PITTSBURGH MOST LIKELY TO SEE IFR CONDITIONS...WITH
MVFR/VFR ELSEWHERE. AFTER A BRIEF BREAK WEDNESDAY AFTERNOON A
SECOND SYSTEM WILL SPREAD SNOW SHOWERS ACROSS THE REGION WEDNESDAY
NIGHT WITH MVFR CIGS LIKELY AND A 50-70% CHANCE OF IFR
RESTRICTIONS OVERNIGHT.
OUTLOOK.../WEDNESDAY THROUGH SUNDAY/...
RESTRICTIONS ARE LIKELY WEDNESDAY NIGHT THROUGH
THURSDAY...SATURDAY...AND AGAIN SUNDAY NIGHT THROUGH MONDAY AS
MULTIPLE FRONTAL SYSTEMS PASS OVER THE AREA.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
155 AM EST TUE FEB 3 2015
.SYNOPSIS...
A FAST MOVING CLIPPER SYSTEM WILL BRING LIGHT SNOW TUESDAY NIGHT
INTO EARLY WEDNESDAY MAINLY NORTH OF PITTSBURGH. A COLD FRONT
WEDNESDAY WILL BRING ANOTHER ROUND OF LIGHT SNOW AND MUCH
REINFORCE THE COLD AIR.
&&
.NEAR TERM /THROUGH TONIGHT/...
TEMPERATURES CONTINUE THEIR DOWNWARD TREND WITH SKIES MOSTLY
CLEARING AND WINDS DISSIPATING. STILL HAVENT COMPLETELY CALMED THE
WINDS AT THIS HOUR...SO TEMPS HAVE NOT BOTTOMED OUT. COLDEST
READINGS THUS FAR ARE NORTH OF I-80 WITH WIND CHILLS DIPPING INTO
THE SINGLE DIGITS BELOW ZERO. SOUTH OF PITTSBURGH...THE
TEMPERATURES HAVE NOT FALLEN AS DRAMATICALLY AS RESIDUAL CLOUDS
AND AN OLDER/RAGGED SNOWPACK HAS KEEP SLOWED THE COOLING. STILL
EXPECTING TEMPS EVERYWHERE TO GET INTO THE SINGLE DIGITS BEFORE DAYBREAK.
SOMEWHAT COMPLICATED FORECAST FOR TODAY AS THERE WILL BE A MIX OF
RESIDUAL LLVL MOISTURE AND HIGH CLOUDS STREAMING IN FROM THE WEST.
THE RAP IS BULLISH ON BRINGING LOW TO MID STRATUS DECK CURRENTLY
OVER SRN WV/KY BACK NORTH INTO OUR AREA. NOT BUYING INTO THIS SOLN
AS DRIER AND WARMER AIR SHOULD HELP EAT AWAY THIS CLOUD DECK AS
THE LLVL FLOW BACKS TO THE SOUTHWEST. THE RESULTANT SKY COVER IS
ON THE OPTIMISTIC SIDE...AHEAD OF THE NEXT SYSTEM THAT WILL
INCREASE CLOUDS TONIGHT.
A QUICK ALBERTA CLIPPER WILL DROP ACROSS THE NRN PLAINS TODAY
STREAMING THROUGH THE WRN GREAT LAKES THIS EVENING. SFC LOW
DEEPENS AS IT PASSES JUST NORTH OF LAKE ERIE TONIGHT. TEMPS
TONIGHT WILL STAY RELATIVELY STABLE THROUGH AS WAA INCREASES AHEAD
OF THE AXIS OF THE MID-LEVEL TROF. DESPITE THE WAA...TEMPS WILL
STAY LOW ENOUGH THAT SNOW WILL BE THE P-TYPE EVERYWHERE THAT
PRECIPITATION IS GENERATED. WITH A LACK OF A SRLY MOISTURE FEED
INTO THE LOW...THE SYSTEM OVERALL IS RELATIVELY MOISTURE
STARVED...KEEPING MOST OF THE SNOW CLOSER TO THE LOW. MODEL
CONSENSUS IS THAT TRACK STAYING JUST NORTH OF LAKE
ERIE...ULTIMATELY KEEPING THE BEST SNOW POTENTIAL IN OUR AREA
NORTH OF I-80. THOSE AREAS SHOULD SEE AN INCH OR TWO TOTAL
ACCUMULATION THROUGH DAY BREAK WEDS. ELSEWHERE...LESS THAN AN
INCH IS EXPECTED.
TAX
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
FAST MOVING CLIPPER WILL INCREASE CLOUDS AHEAD OF IT TUESDAY NIGHT
WITH A PERIOD OF LIGHT SNOW MAINLY ACROSS I-80. LOOKS TO BE A
QUICK INCH FAR NORTH WITH POSSIBLY A COATING DOWN TO THE TURNPIKE.
WARM ADVECTION WILL KEEP TEMPERATURES NEARLY STEADY TUESDAY
NIGHT...WITH MAX TEMPS NEAR AVERAGE WEDNESDAY. NEXT STRONGER COLD
FRONT WILL CROSS WEDNESDAY NIGHT INTO THURSDAY WITH STRONGER UPPER
LEVEL TROUGH. MORE OF A WIDESPREAD LIGHT SNOW EXPECTED WITH AN
INCH OR TWO AS SNOW ENDS EARLY THURSDAY. MUCH COLDER WITH STEADY
OR FALLING TEMPERATURES THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
RIDGING IS PROGGED TO BRIEFLY BLD IN LT IN THE WK BEFORE BROAD
UPR TROFG SETS UP ACRS THE ERN CONUS LTR IN THE WKEND THRU MON
RETURNING SNW SHWR CHCS TO THE RGN. AFT WELL BELOW AVG TEMPS LT IN
THE WK...SOME LIMITED RECOVERY IS EXPD AHD OF THE NXT SHRTWV LTR
IN THE WKEND.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
ONE BAND OF LAKE HURON SNOW SHOWERS IS ADVANCING EASTWARD ACROSS
KAGC TOWARD KLBE AND KFKL THIS EVENING. SNOW SHOWERS IN THIS BAND
LIKELY WILL DROP TO MVFR AS THEY DISSIPATE SLOWLY WITH DRIER AIR
MOVING INTO THE REGION. STRATUS LIKEWISE WILL BE MOVING EAST OF
THE AREA AS DRIER AIR MOVES IN...RESULTING IN VFR CONDITIONS BY
THE OVERNIGHT HOURS AND INTO THE DAY ON TUESDAY AS WINDS SHIFT
FROM THE NORTHWEST TO THE SOUTHWEST AND BECOME LIGHT. FRIES
OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
RSTRNS ARE LIKELY WITH A WED-THU CDFNT...AND AGAIN SAT WITH
ANOTHER APCHG CDFNT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
351 AM EST TUE FEB 3 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EST MON FEB 2 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING INTO NW ONTARIO AND NRN MN. AT THE
SFC...A TROUGH EXTENDED FROM NW ONTARIO THROUGH NW MN INTO ERN SOUTH
DAKOTA AS HIGH PRESSURE BUILDS INTO THE MID MS VALLEY. WINDS BACKING
TO THE SW AHEAD OF THE TROUGH HAVE PUSHED THE LES OFFSHORE FROM THE
CWA. VIS SATELLITE SHOWED POTENTIAL DEVELOPMENT OF AN LES BAND
OFFSHORE FROM THE KEWEENAW BUT WAS LARGELY OBSCURED BY INCREASING
MID/HIGH CLOUDS.
TONIGHT...AS SFC TROF BEGINS TO SAG SE ACROSS THE CWA...A MODERATE
TO POSSIBLY HEAVY DOMINANT LES BAND WILL GET PUSHED SOUTH ACROSS THE
KEWEENAW PENINSULA. WITH 850 MB TEMPS NEAR -19C...CONVECTION/LIFT
THROUGH THE 1K-3K FT DGZ...EXPECT THE POTENTIAL FOR SNOWFALL RATES
IN EXCESS OF 1" PER HOUR AS LES BAND SAGS SOUTH ACROSS THE KEWEENAW.
HOWEVER...SINCE THE BAND IS LIKELY TO MOVE QUICKLY ENOUGH TO LIMIT
OVERALL SNOWFALL AMOUNTS...TOTALS GENERALLY IN THE 2 TO 6 INCH RANGE
ARE EXPECTED. SO...THE LES ADVISORY LOOKS ON TRACK. EXPECT THE SNOW
TO BEGIN TO DIMINISH AND TRANSITION TO MULTIPLE WIND PARALLEL BANDS
AS THE WINDS VEER TO THE NW. OTHERWISE...LES SHOULD REMAIN OFFSHORE
FROM THE ERN CWA UNTIL LATE AS WINDS ONLY VEER FROM WSW TO W.
TUE...280-290 FLOW LES WILL CONTINUE WITH 850 MB TEMPS REMAINING
AROUND -19C. LOWERING INVERSION HEIGHTS BELOW 4K FT WILL LIMIT
POTENTIAL FOR ADDITIONAL ACCUMULATIONS WITH ONLY AN INCH OR TWO WEST
AND 1 TO 3 INCHES EAST...MAINLY EAST OF MUNISING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM EST TUE FEB 3 2015
AT 12Z WED...A SFC COLD FRONT WILL BE OVER THE SERN CWA AHEAD OF A
SHORTWAVE AND MUCH COLDER AIR MOVING INTO THE AREA. NW WIND LES WILL
BE ONGOING AT THE START OF THE PERIOD AND WILL INTENSIFY THROUGH WED
EVENING. 850MB TEMPS WILL BE -20C TO -25C AT 12Z WED BUT WILL
DECREASE TO -25C TO -30C BETWEEN 18Z WED AND 06Z THU. LOW LEVEL
WINDS WILL BE NEARLY UNIDIRECTIONAL INTO EARLY WED
NIGHT...SUPPORTING MULTI BAND LES STRUCTURE. ONE EXCEPTION IS OVER
ERN UPPER MI...BETWEEN GRAND MARAIS AND WHITEFISH POINT...WHERE THE
LAND BREEZE OFF ONTARIO AND ICE COVERAGE ALONG THE ONTARIO SHORE MAY
LEAD TO A STRONGER MORE DOMINANT BAND. LAKE INDUCED EQUILIBRIUM
LEVELS WILL INCREASE TO AROUND 11KFT WED AFTERNOON AND
EVENING...MEANING HEAVY LES. WITH THE COLD TEMPS...THE CONVECTIVE
LAYER WILL BE OUT OF THE DGZ...SO DENDRITE SIZE WILL BE SMALL AND
SNOW TO LIQUID RATIOS BELOW 20 TO 1. WHILE THIS WILL BE A LIMITATION
FOR SNOWFALL AMOUNTS...THE SMALL FLAKES WILL BE EFFICIENT AT
REDUCING . THEREFORE...THE GREATLY LOWERED VISIBILITIES ARE
ANTICIPATED TO BE THE DOMINANT HAZARD DURING THE EVENT. THE LES WILL
DIMINISH FROM W TO E WED NIGHT BEFORE MOVING OFFSHORE THU MORNING AS
A SFC RIDGE MOVES W TO E THROUGH THE AREA. MIN TEMPS WED NIGHT WILL
RANGE FROM 0F ALONG THE SHORELINES TO
-15F
OVER THE INTERIOR W. WILL CONTINUE TO MENTION THESE COLDER TEMPS IN
THE HWO...BUT LIGHT WINDS WILL LIKELY NOT MEET CRITERIA FOR WIND
CHILL ADVISORIES.
A CLIPPER SHORTWAVE LOOKS TO MOVE NE OF THE CWA THU EVENING INTO THU
NIGHT...BUT MOST OF THE PRECIP ASSOCIATED WITH THE SYSTEM LOOKS TO
STAY NE OF THE CWA. SOME LAKE ENHANCED SNOW COULD RESULT ACROSS THE
NRN KEWEENAW PENINSULA AND MAYBE FAR NERN UPPER MI WITH LIGHT
AMOUNTS IF ANYTHING.
QUITE OF BIT OF UNCERTAINTY WITH SMALLER SCALE DETAILS OF A SERIES
OF SHORTWAVE SAT THROUGH MON. TOO EARLY TO SAY IF SYNOPTIC PRECIP
WILL RESULT IN THE CWA. MODELS DO SHOW N-NE WINDS LATE FRI NIGHT
THROUGH AT LEAST SAT /GFS VEERS WINDS TO A SLY DIRECTION WHILE THE
ECMWF KEEPS NE WINDS INTO MON/. THE GFS SHOWS 850MB TEMPS AROUND
-15C...WHICH WOULD FAVOR HIGHER SNOW TO LIQUID RATIOS AND GREATER
SNOWFALL AMOUNTS DURING THE FAVORABLE FLOW. THE ECMWF SHOWS 850MB
TEMPS OF -20C TO -25C...WHICH WOULD FAVOR LOWER RATIOS BUT STRONGER
LES OVERALL AND ALSO LONGER DURATION OF LES INTO MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM EST MON FEB 2 2015
INCREASING MOISTURE LATE TONIGHT WITH THE ARRIVAL OF A SFC TROUGH
WILL ALLOW FOR MVFR CONDITIONS TO RETURN AT KIWD WITH SOME LIGHT LES
EXPECTED LATE TONIGHT.
AT KCMX...IFR VSBYS WILL CONTINUE OVERNIGHT WITH LIFR CONDITIONS
BRIEFLY AT TIMES AS A DOMINANT LES BAND SLOWLY SAGS TO THE SOUTH
ACROSS THE KEWEENAW PENINSULA OVERNIGHT. VSBYS SHOULD IMPROVE TO
MVFR LATE TONIGHT AS WINDS SHIFT MORE NW AND THE DOMINANT LES BAND
MOVES SOUTH OF THE AREA.
AT KSAW...VFR CONDITIONS WILL CONTINUE UNTIL TUE AFTERNOON AS SW
WINDS PREVAIL. THE WIND SWITCHES TO THE W AND ALLOWS MVFR
CLOUDS AND SNOW SHOWERS TO MOVE IN DURING THE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 1148 PM EST MON FEB 2 2015
WEST WINDS WILL VEER WEST NORTHWEST TONIGHT AS A TROUGH MOVES
THROUGH LAKE SUPERIOR. HEAVY FREEZING SPRAY IS EXPECTED OVER
PORTIONS OF THE WRN LAKE THIS AFTERNOON INTO THIS EVENING AND ERN LAKE
SUPERIOR TONIGHT. A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR
TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO
NEAR GALES ARE POSSIBLE WED. HEAVY FREEZING SPRAY IS EXPECTED DURING
THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE SUPERIOR. WINDS WILL
BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH THAT CROSSES LATE
FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE TROUGH INTO THE
WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING
FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1148 PM EST MON FEB 2 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EST MON FEB 2 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING INTO NW ONTARIO AND NRN MN. AT THE
SFC...A TROUGH EXTENDED FROM NW ONTARIO THROUGH NW MN INTO ERN SOUTH
DAKOTA AS HIGH PRESSURE BUILDS INTO THE MID MS VALLEY. WINDS BACKING
TO THE SW AHEAD OF THE TROUGH HAVE PUSHED THE LES OFFSHORE FROM THE
CWA. VIS SATELLITE SHOWED POTENTIAL DEVELOPMENT OF AN LES BAND
OFFSHORE FROM THE KEWEENAW BUT WAS LARGELY OBSCURED BY INCREASING
MID/HIGH CLOUDS.
TONIGHT...AS SFC TROF BEGINS TO SAG SE ACROSS THE CWA...A MODERATE
TO POSSIBLY HEAVY DOMINANT LES BAND WILL GET PUSHED SOUTH ACROSS THE
KEWEENAW PENINSULA. WITH 850 MB TEMPS NEAR -19C...CONVECTION/LIFT
THROUGH THE 1K-3K FT DGZ...EXPECT THE POTENTIAL FOR SNOWFALL RATES
IN EXCESS OF 1" PER HOUR AS LES BAND SAGS SOUTH ACROSS THE KEWEENAW.
HOWEVER...SINCE THE BAND IS LIKELY TO MOVE QUICKLY ENOUGH TO LIMIT
OVERALL SNOWFALL AMOUNTS...TOTALS GENERALLY IN THE 2 TO 6 INCH RANGE
ARE EXPECTED. SO...THE LES ADVISORY LOOKS ON TRACK. EXPECT THE SNOW
TO BEGIN TO DIMINISH AND TRANSITION TO MULTIPLE WIND PARALLEL BANDS
AS THE WINDS VEER TO THE NW. OTHERWISE...LES SHOULD REMAIN OFFSHORE
FROM THE ERN CWA UNTIL LATE AS WINDS ONLY VEER FROM WSW TO W.
TUE...280-290 FLOW LES WILL CONTINUE WITH 850 MB TEMPS REMAINING
AROUND -19C. LOWERING INVERSION HEIGHTS BELOW 4K FT WILL LIMIT
POTENTIAL FOR ADDITIONAL ACCUMULATIONS WITH ONLY AN INCH OR TWO WEST
AND 1 TO 3 INCHES EAST...MAINLY EAST OF MUNISING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 PM EST MON FEB 2 2015
THE UPPER GREAT LAKES REGION REMAINS LOCKED IN NORTHWESTERLY FLOW
ALOFT AS A WEAK RIDGE REMAINS IN PLACE OVER THE WESTERN CONUS AND AN
UPPER LOW SPINS OVER NORTHERN HUDSON BAY. THIS NORTHWESTERLY FLOW
WILL CONTINUE TO BRING OCCASIONAL DISTURBANCES OVER THE AREA AND
KEEP BELOW NORMAL TEMPERATURES IN PLACE THROUGH THE PERIOD.
AT THE START OF THE PERIOD...A WEAK SHORTWAVE WILL BE SLIDING JUST
TO THE SOUTH OF THE CWA...ALTHOUGH THERE COULD BE A LIGHT SNOW
SHOWER BRUSHING SOUTHERN MENOMINEE COUNTY ON TUESDAY EVENING.
MEANWHILE...LIGHT LAKE EFFECT SNOW WILL BE ONGOING IN THE
WEST-NORTHWEST WIND SNOW BELTS OF NORTHERN LAKE SUPERIOR. WHILE
AMOUNTS WON/T BE ANYTHING TOO SIGNIFICANT INITIALLY TUESDAY
EVENING...A STRONGER SHORTWAVE WILL DROP SOUTHEAST ACROSS THE AREA
LATE TUESDAY NIGHT AND WEDNESDAY...BRINGING MUCH COLDER
TEMPERATURES ALOFT TO THE AREA UNDER NORTHWEST WINDS. THESE
TEMPERATURES (850MB TEMPS FALLING FROM -19C AT 00Z WEDNESDAY TO -26C
BY 00Z THURSDAY) WILL HELP STEEPEN THE MID LEVEL LAPSE RATES AND
ALLOW THE INVERSION HEIGHTS TO RISE FROM 5-6KFT TO 10-11KFT.
THUS...WOULD EXPECT THE INTENSITY OF THE SNOW SHOWERS TO QUICKLY
INCREASE LATE TUESDAY NIGHT AND WEDNESDAY MORNING AS THE INVERSION
HEIGHTS RISE AND THERE IS ASSISTANCE (MOISTURE/FORCING) FROM THE
SHORTWAVE. WITH FAIRLY UNIFORM NORTHWESTERLY WINDS DEVELOPING
DURING THE TIME OF INTENSIFICATION...WOULD EXPECT MAINLY MULTIBAND
LES ONCE IT BECOMES ESTABLISHED ON WEDNESDAY...ALTHOUGH THE LAND
BREEZE OFF ONTARIO (AND THE ICE IN THAT AREA OF LAKE SUPERIOR) ON
WEDNESDAY NIGHT COULD LEAD TO A MORE DOMINATE BAND DEVELOPING
SOMEWHERE BETWEEN PICTURED ROCKS AND WHITEFISH POINT AND WILL FOCUS
THE HIGHER POPS/SNOWFALL AMOUNTS THERE. THE MAIN LIMITING FACTOR TO
SNOWFALL AMOUNTS WILL BE THE COLD AIR KEEPING MUCH OF THE CLOUD
OUTSIDE OF THE DGZ AND KEEP RATIOS BELOW 20 TO ONE AND AMOUNTS
LIGHTER. BUT WITH THOSE SMALLER FLAKES...IT WILL BE VERY EFFICIENT
AT REDUCING VISIBILITIES AND THAT WILL LIKELY BE ONE OF THE BIGGEST
IMPACTS WITH THIS EVENT. WINDS WILL BACK WEDNESDAY NIGHT AND
THURSDAY AS THE SURFACE RIDGE MOVES THROUGH THE AREA. THIS WILL
CONTINUE TO LOWER INVERSION HEIGHTS ACROSS THE AREA AND SHIFT WINDS
TO THE SOUTHWEST BY THURSDAY EVENING. THUS...WILL SHOW A WEST TO
EAST DIMINISHING TREND WEDNESDAY NIGHT INTO THURSDAY MORNING BEFORE
THE SNOW MOVES OFF SHORE OF THE U.P. BY THURSDAY AFTERNOON.
MODELS BEGIN TO DIFFER ON SOME OF THE SMALLER DETAILS HEADING INTO
THE WEEKEND...AS A WEAK SHORTWAVE SLIDES SOUTHEAST ACROSS THE GREAT
LAKES REGION. THIS WILL SPREAD AN AREA OF SNOW SHOWERS
EAST-SOUTHEAST ACROSS THE CWA FRIDAY AFTERNOON/NIGHT ON THE NOSE OF
THE MID-LEVEL WARM AIR ADVECTION. WITH DIFFERENCES IN THE TRACK OF
THE BEST SNOWFALL...WILL SHOW CHANCE POPS MOVING ACROSS THE
CWA. BEHIND THIS WAVE...A HIGH PRESSURE RIDGE (FROM A HIGH IN
CENTRAL CANADA) WILL NOSE SOUTHEAST INTO THE CWA AND LEAD TO
NORTHERLY FLOW ACROSS LAKE SUPERIOR. WITH 850MB TEMPS FALLING TO
BETWEEN -14 AND -22C BY SATURDAY EVENING...WOULD EXPECT LAKE EFFECT
SNOW TO DEVELOP LATE FRIDAY NIGHT AND INTO SATURDAY. THE SUBSIDENCE
INVERSION (3-4KFT) WILL LIKELY KEEP THE INTENSITY IN CHECK BUT WILL
NEED TO WATCH THE AMOUNT OF COLD AIR. IF THE WARMER SOLUTION SHOWN
BY THE 12Z GFS PANS OUT...MUCH OF THE CLOUD WOULD BE WITHIN THE DGZ
AND LEAD TO A FEW INCHES OF FLUFFY ACCUMULATION. OTHERWISE...WOULD
EXPECT LIMITED ACCUMULATIONS THROUGH SUNDAY NIGHT WITH THE NNE FLOW
DUE TO THE PERSISTENT SUBSIDENCE INVERSION. THE HIGH WILL SHIFT
EAST OF THE AREA ON MONDAY...ALLOWING SOUTHERLY FLOW TO DEVELOP
AND DIMINISH THE LAKE EFFECT.
AS FOR TEMPS...EXPECT BELOW NORMAL VALUES FOR MOST OF THE
PERIOD...WITH THE ONLY REPRIEVE BEING ON FRIDAY WHEN HIGHS RISE
INTO THE UPPER TEENS AND LOWER 20S. WITH CLEARING EXPECTED ON
WEDNESDAY NIGHT...WOULD EXPECT A PRETTY COLD NIGHT OVER THE
INTERIOR WEST AND HAVE TEMPERATURES FALLING INTO THE TEENS BELOW
ZERO. AS THIS OCCURS...THE WINDS WILL REALLY BE DIMINISHING AND
EXPECT THAT TO KEEP WIND CHILLS IN CHECK FOR LATE WEDNESDAY NIGHT
AND EARLY THURSDAY MORNING. WILL CONTINUE TO MENTION IN THE HWO DUE
TO THE COLD FACTOR...BUT WITH WINDS LIKELY BEING BELOW 10MPH WE
SHOULDN/T NEED A WIND CHILL ADVISORY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM EST MON FEB 2 2015
INCREASING MOISTURE LATE TONIGHT WITH THE ARRIVAL OF A SFC TROUGH
WILL ALLOW FOR MVFR CONDITIONS TO RETURN AT KIWD WITH SOME LIGHT LES
EXPECTED LATE TONIGHT.
AT KCMX...IFR VSBYS WILL CONTINUE OVERNIGHT WITH LIFR CONDITIONS
BRIEFLY AT TIMES AS A DOMINANT LES BAND SLOWLY SAGS TO THE SOUTH
ACROSS THE KEWEENAW PENINSULA OVERNIGHT. VSBYS SHOULD IMPROVE TO
MVFR LATE TONIGHT AS WINDS SHIFT MORE NW AND THE DOMINANT LES BAND
MOVES SOUTH OF THE AREA.
AT KSAW...VFR CONDITIONS WILL CONTINUE UNTIL TUE AFTERNOON AS SW
WINDS PREVAIL. THE WIND SWITCHES TO THE W AND ALLOWS MVFR
CLOUDS AND SNOW SHOWERS TO MOVE IN DURING THE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 1148 PM EST MON FEB 2 2015
WEST WINDS WILL VEER WEST NORTHWEST TONIGHT AS A TROUGH MOVES
THROUGH LAKE SUPERIOR. HEAVY FREEZING SPRAY IS EXPECTED OVER
PORTIONS OF THE WRN LAKE THIS AFTERNOON INTO THIS EVENING AND ERN LAKE
SUPERIOR TONIGHT. A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR
TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO
NEAR GALES ARE POSSIBLE WED. HEAVY FREEZING SPRAY IS EXPECTED DURING
THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE SUPERIOR. WINDS WILL
BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH THAT CROSSES LATE
FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE TROUGH INTO THE
WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST TUESDAY FOR LSZ266-
267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GLASGOW MT
919 PM MST MON FEB 2 2015
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
UPDATE...
ACCUMULATING SNOW WILL CONTINUE TO OVERSPREAD NORTHEAST MONTANA
FOR THE REMAINDER OF THIS EVENING AND FALL STEADIEST AFTER
MIDNIGHT THROUGH EARLY TUESDAY MORNING. A LOOK AT THE 18Z GFS AND
THE 12Z ECMWF REVEAL 2 BULLS-EYES OF HIGHER QPF ACROSS THE
CWA...ONE OVER THE NORTHEAST ZONES AND ONE OVER THE SOUTHWEST.
TOTAL QPF IS GENERALLY ON EITHER SIDE OF 0.1 INCHES AND WITH A
15:1 TO 20:1 SNOW TO WATER RATIO THIS SUPPORTS A SOLID 1-3 INCHES
ACROSS THE AREA. ANY LOCALIZED BANDS THAT DO HAVE SOMEWHAT HIGHER
SNOWFALL RATES OR THAT DO PERSIST MAY ALLOW FOR LOCALIZED HIGHER
AMOUNTS. EXPECT THAT THE GREATEST CHANCES FOR 4 INCH TOTALS WOULD
BE OVER THE HIGHER TERRAIN NORTHWEST OF GLENDIVE AND ALSO OVER THE
LITTLE ROCKY MOUNTAINS.
THE CHALLENGE THIS EVENING REALLY WAS PETROLEUM COUNTY. 00Z NAM
SOLUTION HAS LIGHTER QPF. HOWEVER...SSEO WINTER WEATHER PRODUCTS
AS WELL AS OTHER AVAILABLE MESOSCALE GUIDANCE SUPPORT ENOUGH
MIDLEVEL WARMER AIR WORKING ITS WAY INTO THE COLUMN THAT FREEZING
RAIN AND/OR SLEET COULD FACTOR IN. RECENT TEMPERATURES ARE IN THE
TEENS AT GLASGOW...31 AT WINNETT...AND 40 AT LEWISTOWN. IF THAT
WARMER AIR OVERRIDES SHALLOW COLD SURFACE AIR...EVEN LIGHT QPF
COULD BE PROBLEMATIC. IN FACT...WOULD NOT BE SURPRISED IF AREAS
NEAR AND SOUTH OF WINNETT EVEN GO TO PLAIN RAIN FOR A TIME. AS A
RESULT...INCLUDED PETROLEUM COUNTY IN THE WINTER WEATHER ADVISORY
FOR THE COMBINATION OF AN INCH OR TWO OF SNOW AND A TRACE OF ICE
DUE TO SLEET OR FREEZING RAIN. FOR THE REST OF THE CWA...FAIRLY
HIGH CONFIDENCE ON SNOW AMOUNTS. NAM BUFKIT SOUNDINGS CONTINUE TO
SHOW PRECIPITABLE WATER VALUES APPROACHING +2SD COMPARED WITH
CLIMATOLOGY AFTER MIDNIGHT TONIGHT. MIXING RATIOS OF 1-3 G/KG AT
700MB ALSO SUPPORT THE IDEA THAT THERE IS PLENTY OF MOISTURE
AVAILABLE TONIGHT BUT THAT QUICKLY GETS SHUNTED SOUTH ON TUESDAY.
WILL CLOSELY MONITOR WHERE STEADIER BANDS SET UP OVERNIGHT AND
KEEP AN EYE ON PRECIPITATION TYPE OVER PETROLEUM COUNTY OVERNIGHT
AND BETTER REFINE THE FORECAST AS NEEDED. MALIAWCO
PREVIOUS DISCUSSION...
FORECAST CHALLENGE IN THE SHORT TERM FORECAST PERIOD DEALS WITH
THE EFFECTS FROM THE NEXT ACCUMULATING SNOWFALL EXPECTED LATER
TONIGHT THROUGH TUESDAY ACROSS NORTHEAST MONTANA.
MODELS SEEM TO BE IN GENERAL GOOD AGREEMENT WITH TIMING OF
PRECIP...BUT SOME OF THE SMALLER-SCALE ISSUES WHICH MAY RESULT IN
LESS FORECAST CONFIDENCE ARE EXACTLY WHERE SOME OF THE HEAVIER
SNOW BANDS SET UP. COULD BE THE DIFFERENCE BETWEEN 1 OR 3 INCHES
OF SNOW FOR MANY LOCATIONS.
FOR EXAMPLE...00Z TO 06Z TONIGHT GFS AND NAM SHOW A NORTHERN
ZONES BAND OF SNOW AND A SW ZONES BAND OF MIXED PRECIP. THE EC ON
THE OTHER HAND IS MUCH WEAKER AND THE HRRR PLACES A BAND OF SNOW
OVER THE CENTRAL CWA.
FROM 06Z TO 12Z...GFS PAINTS A HEFTY WIDESPREAD ALMOST MODERATE
SNOWFALL ACROSS MOST OF OUR CENTRAL CWA WHILE THE EC KEEPS THE
HEAVIER SNOW OVER OUR FAR EASTERN AND SW ZONES.
AFTER TUESDAY MORNING...MOST OF THE HEAVIER SNOWFALL WILL HAVE
EASED TO MORE SCATTERED LIGHT SNOW SHOWERS WHICH WILL LIKELY
LINGER THROUGH THE REMAINDER OF THE DAY.
MODELS ARE ALSO INDICATING A GOOD CHANCE THAT SKIES WILL QUICKLY
AND EFFECTIVELY CLEAR FROM NORTH TO SOUTH FOR TUESDAY NIGHT
THROUGH WEDNESDAY MORNING. WITH A FRESH SNOW PACK...DECIDED TO
DROP LOW TEMPERATURES FOR WEDNESDAY MORNING QUITE A BIT BELOW
GUIDANCE GIVEN THE STRONGER THAN USUALLY EXPECTED RADIATIONAL
COOLING.
WINDS THROUGHOUT ARE EXPECTED TO BE OF MINIMAL IMPACT IF ANY AT
ALL. BMICKELSON
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
UPDATE...GOING FORECAST IN OVERALL GOOD SHAPE. BIGGEST CHANGES
MADE...BASED OFF THE 12Z EXTENDED MODELS...WAS TO GO CONSERVATIVE
WITH THE WARM UP FOR LATE INTO THE WEEK INTO THE WEEKEND. CURRENT
THINKING IS THAT WITH RECENT SNOW COVER...WARMING WILL BE HINDERED
BY A LOW LEVEL INVERSION. THUS TRENDED DOWN TEMPS ACROSS THE
NORTHEAST THROUGH THE AFOREMENTIONED PERIOD. ALSO TRENDED UP POPS
FOR EXPECTED MIXED PRECIP THURSDAY NIGHT THROUGH SATURDAY NIGHT.
GILCHRIST
PREVIOUS DISCUSSION...MILD WEATHER RETURNS TO MONTANA FOR THE END
OF THE WEEK WITH THE HUDSON BAY LOW WEAKENING AND PACIFIC UPPER
RIDGE PUSHING INTO THE NORTHERN ROCKIES. WITH THE OPENING UP OF
FLOW OFF THE PACIFIC INSTEAD OF OUT OF THE ARCTIC...WARM AIR WILL
SPREAD ACROSS THE DIVIDE SENDING TEMPERATURES BACK ABOVE NORMAL.
NEW SNOW COVER WILL SLOW THE WARMING SLIGHTLY BUT DOWNSLOPE WINDS
WILL AID THE MIXING.
SEVERAL SHORTWAVES MOVE ACROSS THE TOP OF THE RIDGE...WITH THE
MOST SUBSTANTIAL ONE FORECAST FOR FRIDAY INTO SATURDAY ALTHOUGH
MODEL SPREAD LARGE ENOUGH FOR UNCERTAINTY ON WHEN DURING THE
WEEKEND ANY PRECIPITATION WILL OCCUR. TEMPERATURES PROFILES
SUGGEST A MIX OF PRECIP TYPES POSSIBLE WITH THE CRITICAL THERMAL
BOUNDARY LINGERING OVER NORTHEAST MONTANA. EBERT
&&
.AVIATION...
SYNOPSIS: A LOW OVER NORTHWESTERN MONTANA WILL MOVE SOUTHEAST
ACROSS THE STATE OVERNIGHT EXITING INTO SOUTH DAKOTA BY 15Z.
FLIGHT CATEGORY: VFR FALLING TO LIFR/IFR BY 05Z LASTING THROUGH 15Z.
CIGS AND VSBY: VFR CEILINGS FALLING TO 500 TO 1500 FEET
OVERNIGHT... VSBY FALLING TO 1/2 SM AT TIMES AFT 05Z IMPROVING BY 15Z.
PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST TUESDAY FOR CENTRAL AND
SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...
DAWSON...EASTERN ROOSEVELT...GARFIELD...MCCONE...NORTHERN
PHILLIPS...NORTHERN VALLEY...RICHLAND...SOUTHWEST PHILLIPS...
WESTERN ROOSEVELT.
WINTER WEATHER ADVISORY UNTIL 5 PM MST TUESDAY FOR PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1219 AM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 1219 AM CST TUE FEB 3 2015
NO MAJOR CHANGES WERE MADE FOR THIS UPDATE. ONLY MINOR TWEAKS TO
NEAR TERM FORECAST TO CAPTURE LATEST TRENDS.
SNOW CONTINUES TO SPREAD ACROSS WESTERN NORTH DAKOTA LATE THIS
EVENING. BROUGHT CHANCES FOR SNOW EAST A LITTLE EARLIER THAN
PREVIOUS FORECAST AS SNOWBANDS ARE ENTERING CENTRAL NORTH DAKOTA A
LITTLE QUICKER THAN EXPECTED. OTHERWISE ONGOING FORECAST LOOKS
GOOD.
UPDATE ISSUED AT 951 PM CST MON FEB 2 2015
THE INCOMING 00 UTC DETERMINISTIC SUITE AND LATEST RADAR TRENDS
THROUGH 0345 UTC CONTINUE TO AFFIRM THE ONGOING FORECAST OF
WIDESPREAD LIGHT SNOWFALL ACCUMULATIONS ACROSS MUCH OF WESTERN AND
CENTRAL NORTH DAKOTA TONIGHT INTO TUESDAY. MINIMAL CHANGES
REQUIRED TO INCORPORATE OBSERVED TRENDS THROUGH 0330 UTC.
UPDATE ISSUED AT 633 PM CST MON FEB 2 2015
NO SIGNIFICANT CHANGES REQUIRED OTHER THAN TO BLEND TO OBSERVED
TRENDS THROUGH 00 UTC. WIDESPREAD 1 TO 2 INCHES OF SNOW FOR
WESTERN AND MUCH OF CENTRAL NORTH DAKOTA REMAINS ON TRACK FOR LATE
TONIGHT INTO TUESDAY...SUPPORTED BY THE 18 UTC GUIDANCE SUITE AND
20-22 UTC HRRR ITERATIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
THIS AFTERNOON...WEAK HIGH PRESSURE OVER THE REGION WILL ALLOW FOR
MAINLY PARTLY TO MOSTLY SUNNY SKIES. THEN TONIGHT ANOTHER WEAK
CLIPPER SYSTEM WILL MOVE ACROSS NORTH DAKOTA AND EXIT THE REGION
TUESDAY. MOISTURE CHARACTERISTICS ARE SIMILAR TO PAST FEW SYSTEMS
AND THE RESULT SHOULD BE SIMILAR WITH 1 TO 2 INCH SNOW TOTALS WITH
PERHAPS AN ISOLATED 3 INCH TOTAL. THE BAND OF SNOW SHOULD SPREAD
NORTHWEST TO SOUTHEAST ACROSS THE REGION. WINDS WILL NOT BE
SIGNIFICANT WITH THIS SYSTEM. WITH ADVANCING CLOUDS THIS EVENING DO
NOT EXPECT SIGNIFICANT TEMPERATURE FALLS TONIGHT. LOWS -3 NORTH
CENTRAL TO 15 ABOVE FAR SOUTHWEST. TUESDAY WILL SEE HIGHS AROUND 10
NORTH CENTRAL TO 28 SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM CST MON FEB 2 2015
AN ACTIVE PATTERN WILL HIGHLIGHT THE LONG TERM.
THE 12Z DETERMINISTIC MODELS PROVIDE GOOD AGREEMENT ON THE OVERALL
UPPER LEVEL PATTERN REMAINING NORTHWEST ALOFT THROUGH MUCH OF THE
EXTENDED. THIS PATTERN RESULTS IN SEVERAL SHORT WAVES AND
FREQUENT CHANCES FOR PRECIPITATION...FRIDAY THROUGH MONDAY. MUCH
OF THE PRECIPITATION IS EXPECTED TO BE SNOW...ALTHOUGH PERIODS OF
RAIN/FREEZING RAIN/WINTRY MIX ARE POSSIBLE. PREDICTABILITY OF
SHORTWAVES EMBEDDED IN THE FAST NORTHWEST FLOW IS LOW...SO TIMING
AND EXACT LOCATIONS WILL CHANGE WITH FUTURE FORECAST.
A GENERAL WARMING TREND WITH ABOVE AVERAGE TEMPERATURES FOR MUCH OF
NORTH DAKOTA WILL COMMENCE THURSDAY. THE 12Z ENSEMBLES AGREE ON WARM
AIR ADVECTION MOVING INTO THE STATE FROM THE SOUTHWEST...AS A RIGID
OVER THE PACIFIC PROPAGATES EASTWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1219 AM CST TUE FEB 3 2015
WIDESPREAD MVFR/IFR CONDITIONS IN SNOW DEVELOPING ACROSS WESTERN AND
CENTRAL NORTH DAKOTA LATE TONIGHT INTO TUESDAY MORNING...IMPROVING
TO MVFR/VFR THROUGH TUESDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...WAA
LONG TERM...AC
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CST MON FEB 2 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 204 PM CST MON FEB 2 2015
HIGHLIGHTS/CONCERNS...
1. WILL IT STAY DRY TONIGHT
2. TEMPERATURES TONIGHT
3. INCOMING SNOW FOR TUESDAY...IMPACTING THE EVENING COMMUTE.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED NORTHWEST FLOW FROM THE PACIFIC NORTHWEST INTO THE
SOUTHEASTERN U.S.. 2 SHORTWAVES OF NOTE WITHIN THIS FLOW WERE OVER
SOUTH DAKOTA AND COMING INTO CENTRAL BRITISH COLUMBIA. THE SHORTWAVE
OVER SOUTH DAKOTA...DESPITE LOOKING DECENT ON WATER VAPOR...HAS BEEN
PRODUCING NOTHING MORE THAN SOME MID AND HIGH CLOUDS. THIS IS DUE TO
PLENTIFUL DRY AIR PRESENT ACROSS THE DAKOTAS INTO THE FORECAST AREA
SEEN ON 12Z SOUNDINGS. PRECIPITABLE WATER VALUES AT 12Z WERE
GENERALLY 0.05-0.10 INCHES...OR AROUND 30 PERCENT OF NORMAL. THIS
DRY AIR WAS ALSO COLD WITH 925MB TEMPS BETWEEN -14 AND -17C AT 18Z
TODAY PER RAP ANALYSIS FROM THE EASTERN DAKOTAS EASTWARD INTO
MICHIGAN. THUS...DESPITE SUNSHINE...THE FRESH SNOW COVER AND THE
COLD AIR ALOFT HAS ONLY ALLOWED TEMPERATURES TO REACH INTO THE
SINGLE DIGITS TO TEENS ABOVE ZERO...COLDEST WEST OF HIGHWAY 52 WHERE
ALBEDO VALUES ARE VERY HIGH. LAST ITEM OF NOTE WAS A POTENT TROUGH
DROPPING SOUTH THROUGH THE NORTHWEST TERRITORIES...WHICH IS PROGGED
TO COME THROUGH THE REGION LATE WEDNESDAY.
FOR TONIGHT...THE SHORTWAVE EVIDENT OVER THE DAKOTAS HAS EVEN
TRENDED A LITTLE MORE SOUTHWEST COMPARED TO YESTERDAY...HEADING
ACROSS NORTHEAST MISSOURI BY 04Z. GIVEN THE DRY AIR MASS IN PLACE
AND THE TRACK OF THE SHORTWAVE...FEEL CONFIDENT TO KEEP THE FORECAST
DRY. THIS IS IN LINE TOO WITH ALL MODEL QPF OUTPUT. STILL WE SHOULD
SEE A PERIOD OF MID AND HIGH CLOUDS THROUGH THE EARLY OVERNIGHT. ITS
POSSIBLE WE COULD HAVE A PERIOD OF CLEARING BETWEEN 08-10Z...
PROVIDED ECMWF 925MB RH FIELD IS CORRECT IN NOT SHOWING ANY LOW
CLOUDS IN THE WAKE OF THE SHORTWAVE...BEFORE MORE CIRRUS MOVES IN.
IF THIS CLEAR PERIOD MATERIALIZES...WINDS ARE RELATIVELY LIGHT SO
TEMPERATURES COULD TANK EASILY BELOW ZERO. WITH ANTICYCLONIC LOW
LEVEL FLOW...FEEL THE CLEARING IS MORE LIKELY...AND THUS LOWERED
LOWS SOME TOWARDS THE COLDER ECMWF/CANADIAN GUIDANCE.
FOR TUESDAY. THE SHORTWAVE CURRENTLY COMING INTO BRITISH COLUMBIA IS
PROGGED TO REACH NORTHERN IOWA BY 00Z WEDNESDAY. ALTHOUGH THIS
SHORTWAVE IS WEAKER THAN THE ONE THAT COMES THROUGH TONIGHT...THERE
IS A LONGER PERIOD TO BRING IN MOISTURE. PRECIPITABLE WATER CLIMBS
TO 0.3 TO 0.4 INCHES...WHICH IS MUCH CLOSER TO NORMAL.
ADDITIONALLY...MODELS SHOW A FAIRLY STRONG FRONTOGENESIS AND
FRONTOLYSIS COUPLET BETWEEN 900-700MB...WITH ITS FORCING CORRELATED
NICELY WITH THE DENDRITIC GROWTH ZONE. THUS...FEEL VERY CONFIDENT OF
SEEING A FLUFFY SNOW BAND SET UP.
TRACK...GOOD MODEL CONSENSUS REMAINS FOR LOCATIONS SOUTHWEST OF I-94
TO BE IMPACTED...AND IT COULD EVEN REACH AS FAR NORTH AS TAYLOR
COUNTY. SOME DIFFERENCES FOR THE MOST ACCUMULATION...EITHER AROUND I-
90 OR THROUGH NORTHEAST IOWA...AND FOR NOW TOOK A COMPROMISE.
TIMING...SOME SNOW COULD ARRIVE FROM THE WEST INTO LOCATIONS WEST OF
THE MS RIVER BY 18Z...BUT MUCH OF IT SHOULD FALL BETWEEN 18-00Z. THE
SNOW SHOULD EXIT THE SOUTHEAST END OF THE FORECAST AREA BY 03Z.
AMOUNTS...MAXIMUM MODEL QPF IN THE 0.15 TO 0.2 RANGE SEEMS
REASONABLE GIVEN THE FORCING AND PRECIPITABLE WATER...WHICH COULD
SUPPORT BASED ON THE FLUFFY SNOW IDEA UPWARDS OF A LOCALIZED 3
INCHES. MOST ACCUMULATIONS SHOULD FALL BETWEEN 1-2 INCHES...
THOUGH...DUE TO THE QUICK NATURE OF THE FORCING.
ALTHOUGH THE AMOUNTS ARE BELOW ADVISORY CRITERIA...THE TIMING COMING
THROUGH IMPACTING THE EVENING COMMUTE MAY WARRANT ONE IN LATER
FORECASTS...ESPECIALLY IF QPF INCREASES. RIGHT NOW HAVE CONTINUED
TO ADDRESS IN OTHER SERVICES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 204 PM CST MON FEB 2 2015
HIGHLIGHTS/CONCERNS...
1. TRACK OF ACCUMULATING SNOW ON WEDNESDAY
2. LOWS/WIND CHILLS WEDNESDAY NIGHT AND POSSIBLE ADVISORY NEED
3. BRIEF WARM UP TOWARDS NORMAL FOR FRIDAY INTO SATURDAY
4. POTENTIAL FOR MORE ACCUMULATING SNOW THIS WEEKEND
5. ANOTHER COLD SHOT FOR LATE IN THE WEEKEND
THE CURRENT UPPER TROUGH OVER THE NORTHWEST TERRITORIES IS PROGGED
TO DROP DOWN INTO THE REGION AROUND WEDNESDAY EVENING. AS THIS
TROUGH APPROACHES ALL MODELS ARE DEVELOPING A WEST TO EAST
FRONTOGENETIC BAND OF ACCUMULATING SNOW FOR WEDNESDAY. THE TRACK OF
THIS BAND RANGES FROM SOUTH OF I-80 IN THE 02.12Z NAM/GFS WHICH
WOULD BE DRY FOR OUR AREA...AROUND I-80 FROM THE 02.12Z CANADIAN
WITH A BRIEF BRUSH OF LIGHT SNOW ACROSS THE FAR SOUTH...AND AROUND
TO JUST NORTH OF I-80 FROM THE 02.00Z/12Z ECMWF WHICH COULD BRING
SNOW AS FAR NORTH AS I-90. HAVE TO MAINTAIN SOME LOW CHANCES OF
PRECIPITATION SOUTH OF I-90 DUE TO THE ECMWF/CANADIAN. HOPEFULLY
LATER MODEL RUNS WILL COME INTO BETTER AGREEMENT. THE MORE BULLISH
ECMWF WOULD YIELD 1-2 INCHES OF ACCUMULATION SOUTH OF I-90.
MUCH COLDER AIR MOVES IN FOR WEDNESDAY NIGHT WITH THE UPPER
TROUGH...AS 925MB TEMPS FALL TO -16 TO -20C BY 12Z THURSDAY. IT DOES
LOOK BRISK DURING THE EVENING...BUT ARCTIC HIGH PRESSURE MOVING IN
OVERNIGHT WILL ALLOW WINDS TO BECOME LIGHT. EXPECT THE LIGHTENING
WINDS TO HELP THE WIND CHILL SITUATION AND WE MAY BE ABLE TO SQUEAK
BY WITHOUT AN ADVISORY. HOWEVER...TEMPERATURES WILL TANK AS SKIES
CLEAR AND WINDS DIMINISH. READINGS SIMILAR TO THIS MORNING ARE
LIKELY.
A NORTHWEST FLOW LOOKS TO PERSIST IN THE WAKE OF THE WEDNESDAY NIGHT
UPPER TROUGH AND INTO EARLY NEXT WEEK. THIS FLOW SEPARATES AN ARCTIC
COLD AIRMASS ACROSS MUCH OF CANADA AND WARMER AIR ACROSS THE WESTERN
U.S. INTO THE CENTRAL PLAINS. SMALL PERTURBATIONS/SHORTWAVES
MIGRATING THROUGH THE NORTHWEST FLOW WILL MODULATE HOW MUCH OF THE
WARMER AND COLDER AIR ENTERS THE FORECAST AREA. TAKE FOR EXAMPLE
FRIDAY INTO SATURDAY MORNING WHERE THE 02.12Z GFS BRINGS 850MB TEMPS
UP TO 2-9C ABOVE...WITH THE ECMWF NOT TOO DISSIMILAR. SNOWPACK AND
LOWER SUN ANGLE PREVENTS MIXING TO 850MB...BUT STILL WE SHOULD SEE
HIGHS CLIMB AT LEAST BACK TOWARDS NORMAL. ALSO FOR SATURDAY INTO
SATURDAY NIGHT...A FRONTOGENETIC BAND OF SNOW LOOKS TO DROP SOUTH
INTO THE FORECAST AREA. THIS FEATURE HAS BEEN CONSISTENT BUT
PLACEMENT ISSUES/TIMING EXIST...SO PRECIPITATION CHANCES IN THE 30-
50 RANGE PERSIST. THE BAND COULD PERSIST INTO SUNDAY PER 02.12Z GFS
SO STILL HAVE LOWER CHANCES. IN THE WAKE OF THIS SNOW...THERE ARE
SUGGESTIONS FOR A DEEPER TROUGH TO FORM OVER THE EASTERN U.S. FOR
SUNDAY INTO MONDAY...ALLOWING SOME OF THE ARCTIC AIR TO OUR NORTH TO
FLOW IN. THUS...COLDER CONDITIONS ARE FORECAST DURING THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1100 PM CST MON FEB 2 2015
MID LEVEL CLOUDS HAVE BEEN DRYING UP...PER LATEST SATELLITE IMAGERY.
NAM BUFKIT SOUNDINGS REMAIN BULLISH ON DEVELOPING NEAR SFC
SATURATION OVERNIGHT...BUT WITHOUT ANY REAL-TIME SUPPORT...WILL KEEP
ANY CIGS VFR FOR NOW.
ANOTHER SHORTWAVE TROUGH SPINS INTO THE AREA TUE. SATURATION IS
BETTER WITH THIS SYSTEM...ENOUGH SO THAT A 6-10 HOUR PERIOD OF -SN
LOOKS LIKELY FOR KRST/KLSE. AMOUNTS UP TO 2 INCHES EXPECTED AT THE
MOMENT. MVFR CIGS SHOULD ACCOMPANY THE SNOW...WITH SOME IFR POSSIBLE
AT KRST. VSBYS FROM 1-2SM ALSO ANTICIPATED WITH THE HEAVIER
SNOWFALL. START TIME LOOKS CLOSE TO 18Z FOR KRST...AND 19-20Z AT
KLSE. SNOW SHOULD CLEAR KRST BY 03Z AND KLSE TOWARD 05Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1028 PM MST MON FEB 2 2015
.UPDATE...
ISSUED AT 1023 PM MST MON FEB 2 2015
IN AN EARLIER UPDATE...WENT AHEAD AND UPGRADED THE WINTER WEATHER
ADVISORIES FOR THE SNOWY AND SIERRA MADRE RANGES TO WARNINGS.
SNOTEL OBSERVATIONS HAD WIDESPREAD ,5 INCH SWE AND MEDICINE BOW
HAD ALMOST 2 INCHES OVER THE PAST 24 HOURS. 00Z GUIDANCE SHOWING
SHOWERS CONTINUING OUT THERE THROUGHWEDNESDAY...SO DECIDED TO
UPGRADE TO WARNINGS. ALSO ADDED ZONES EAST OF THE LARAMIE RANGE TO
A WINTER STORM WATCH AS 00Z NAM AND GFS SHOWING HEFTY QPFS OVER
THE CENTRAL AND SOUTHERN PANHANDLE...EXTENDING UP NEAR WHEATLAND
TOMORROW NIGHT INTO WEDNESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 200 PM MST MON FEB 2 2015
MAIN CONCERNS WILL BE WINDS EARLY IN THE PERIOD...THEN THE SNOW
EVENT EXPECTED LATE TUESDAY NIGHT AND WEDNESDAY.
WINDS HAVE EASED OVER THE WIND-PRONE AREAS OF SOUTHEAST WYOMING AS
EXPECTED THIS AFTERNOON BUT EXPECT THEM TO RISE ONCE AGAIN AS THE
EVENING PROGRESSES. 700MB WINDS OF 60-65 KTS PROGGED OVER PARTS OF
THE LARAMIE RANGE LATER THIS EVENING AND WITH COLOCATION OF DECENT
DOWNWARD MOTION THE TYPICAL WIND AREAS SUCH AS BORDEAUX AND WEST
OF CHEYENNE SHOULD SEE HIGH WINDS ATTAINED ONCE AGAIN. STRONGER
WINDS LOOK TO SHIFT SLOWLY SOUTHWARD EARLY TUESDAY MORNING THEN
SLOWLY DROP OFF BY TUESDAY AFTERNOON. FAIRLY QUIET WEATHER
EXPECTED ELSEWHERE OVER THE CWA TONIGHT THROUGH TUESDAY WITH MILD
TEMPERATURES THOUGH PERIODS OF ENHANCED SNOW SHOWER ACTIVITY WILL
CONTINUE OVER THE HIGHER MTNS. WITH DECENT SNOWFALL ALREADY HAVING
FALLEN THERE AND AN ANTICIPATED INCREASE AGAIN LATER THIS EVENING
HAVE POSTED A WINTER WX ADVY THERE BEGINNING LATE THIS EVENING AND
CONTINUING THROUGH WEDS MORNING. THE SNOW WILL WANE FOR A TIME
TUESDAY AFTERNOON BUT INCREASE AGAIN TUESDAY NIGHT INTO WEDS.
ATTENTION WILL THEN TURN TO A DECENT SNOW EVENT WHICH WILL BEGIN
LATER TUESDAY EVENING AND CONTINUE INTO WEDS. A PUSH OF COLD
CANADIAN AIR WILL BEGIN MOVING ACROSS THE CWA TUESDAY EVENING AND
HOLD IN PLACE THROUGH WEDS AS THE SURFACE HIGH DROPS SOUTHEAST
OVER THE NORTHERN AND CENTRAL PLAINS. A PERIOD OF GOOD UPSLOPE
FLOW COMBINED WITH OVERRUNNING UPPER WNW FLOW AND EMBEDDED WEAK
IMPULSES SHOULD CREATE A FAIRLY EXTENSIVE AREA OF SNOW THAT WILL
MOVE ACROSS THE CWA MAINLY FROM AFTER MIDNIGHT TUESDAY NIGHT
THROUGH WEDS MORNING. RIGHT NOW AMOUNTS LOOK TO BE GENERALLY IN
THE 3-5 INCH RANGE OVER LOWER ELEVATIONS WITH HIGHER AMOUNTS OVER
THE MTNS. LOOKS LIKE A SOLID ADVY EVENT BUT WILL HOLD OFF ON
ISSUING ANY OTHER HILITES AND SEE IF LATER MODEL RUNS PERSIST WITH
THIS SCENARIO. FORTUNATELY WINDS SHOULD BE MODEST OVERALL THOUGH A
SHORT PERIOD OF GUSTINESS LOOKS LIKELY IMMEDIATELY BEHIND THE
FRONT. SNOW WILL TAPER OFF AND END FROM NORTH TO SOUTH WEDS
AFTERNOON AS THE UPSLOPE FLOW ENDS.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 200 PM MST MON FEB 2 2015
LONG TERM LOOKS TO BE WINDY WITH SEVERAL HIGH WIND EVENTS LOOKING
LIKELY.
FOR THURSDAY...LOOKS LIKE WE WILL BE IN FAST NORTHWEST FLOW AS
RIDGE AXIS LOOKS TO REMAIN WELL WEST OVER SOUTHERN NEVADA THROUGH
NORTHERN IDAHO. GFS 700MB WINDS 55-60KTS OVER WESTERN HALF OF THE
CWFA...SO COULD BE SEEING STRONG WINDS AT ARLINGTON AND MAYBE AS
FAR EAST AS THE SOUTH LARAMIE RANGE.
WINDS TURN MORE WESTERLY THURSDAY NIGHT INTO FRIDAY AS RIDGE AXIS
MOVES EAST OF OUR AREA. GFS 700MB WINDS FORECAST UP TO 70-75KTS.
NOT REALLY A BIG 700MB CRAIG TO CASPER HEIGHT GRADIENT...SO THAT
MAY KEEP WINDS DOWN SOME. SOMETHING TO WATCH THOUGH.
NICE THING THOUGH WITH THESE STRONG WINDS ARE THAT TEMPERATURES
ARE GOING TO BE WARM. GFS 700MB TEMPERATURES CLIMB FROM -3C
THURSDAY MORNING TO +4C THURSDAY AFTERNOON. DEPENDING ON SNOW PACK
FROM WEDNESDAYS STORM...WE COULD BE SEEING TEMPERATURES CLIMB BACK
TO THE MID 40S WEST AND LOW 50S EAST.
ANOTHER WARM AND WINDY DAY FRIDAY AS GFS WINDS REMAIN AT 60-70KTS
AND 700MB TEMPERATURES CLIMB TO +5C. LOOKS WINDY AND WARM THROUGH
THE WEEKEND AS WE STAY IN THIS FAST WEST TO NORTHWEST FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1023 PM MST MON FEB 2 2015
WILL BEGIN SEEING LOWERING CONDITIONS BEGINNING THIS MORNING OVER
CARBON COUNTY FOR KRWL. FRONT DOES NOT LOOK TO MOVE INTO AREAS
EAST UNTIL LATE TUESDAY AFTERNOON/EARLY EVENING AND THIS SHOULD BE
WHEN WE SEE DETERIORATING CONDITIONS AT OUR NEBRASKA AIRPORTS AND
HERE AT KCYS. FOLLOWED LATEST HRRR GUIDANCE ON CONDITIONS.
&&
.FIRE WEATHER...
ISSUED AT 200 PM MST MON FEB 2 2015
NO CONCERNS ANTICIPATED FOR THE FORESEEABLE FUTURE WITH CONDITIONS
OTHER THAN WINDS REMAINING NON-CRITICAL. GUSTY WINDS WILL OCCUR
AROUND THE SE WY MTNS AT TIMES THIS WEEK. WIDESPREAD SNOW IS
EXPECTED TUESDAY NIGHT AND WEDS WITH SOME LIGHT TO MODERATE
ACCUMULATIONS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR WYZ106>108-118-119.
HIGH WIND WARNING UNTIL NOON MST TUESDAY FOR WYZ106-117.
WINTER STORM WARNING UNTIL 2 PM MST WEDNESDAY FOR WYZ112-114.
HIGH WIND WARNING UNTIL NOON MST TUESDAY FOR WYZ110-116.
NE...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR NEZ003-019>021-054-055-096.
&&
$$
UPDATE...GCC
SHORT TERM...RE
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
736 AM EST TUE FEB 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST TUE FEB 3 2015
CONCERNS FOCUS ON LES AND ADVISORY HEADLINES OVER THE KEWEENAW
PENINSULA THIS MORNING.
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING ACROSS NRN ONTARIO AND EXITING LAKE
SUPERIOR TO THE NE. AT THE SFC...A TROUGH EXTENDS ACROSS THE SRN
PORTION OF LAKE SUPERIOR AND THE KEWEENAW PENINSULA THIS MORNING.
THIS TROUGH ALONG WITH ENHANCED CONVERGENCE FROM LAND BREEZES OFF
UPPER MI HAS FOCUSED A DOMINANT LES BAND ACROSS THE SRN PORTION OF
LAKE SUPERIOR INTERSECTING THE KEWEENAW PENINSULA BTWN HOUGHTON AND
CALUMET. VISIBILITY BRIEFLY DROPPED TO 1/4 MILE AT KCMX AS THIS BAND
MOVED ACROSS THE AREA SHORTLY AFT MIDNIGHT.
TODAY... WITH THE ONTARIO SHORTWAVE DEPARTING NE OF LAKE SUPERIOR WE
ALREADY MAY BE SEEING SIGNS OF DOMINANT LES BAND WEAKENING OVER SRN
LAKE SUPERIOR AND THE SRN PORTION OF THE KEWEENAW PENINSULA. IT
APPEARS THAT CLOUD TOPS ARE WARMING WHERE THE LES BAND IS LOCATED AS
NOTED ON IR SATELLITE IMAGERY AND REFLECTIVITY RETURNS MAY ALSO BE
WEAKENING SOME WITHIN THE PAST HR. LOOKING AT MODEL FCST SOUNDINGS
WOULD EXPECT WEAKENING TREND TO CONTINUE WITH THIS DOMINANT LES BAND
THROUGH THE MORNING HRS AS INVERSION BASES LOWER FM 5KFT TO 3KFT...
DRYING OCCURS BLO THE INVERSION...AND LOW-LVL CONVERGENCE WEAKENS.
280-290 FLOW LES WILL CONTINUE ACROSS SRN LAKE SUPERIOR INTO NW AND
FAR NE UPPER MI WITH 850 MB TEMPS REMAINING -19/-20C. BUT LOWERING
INVERSION HEIGHTS...DRYING BLO INVERSION AND WEAKENING CONVERGENCE
WILL LIMIT POTENTIAL FOR ADDITIONAL ACCUMULATIONS TO 1 TO 3 INCHES
NW AND 1-2 INCHES ALONG ERN SHORELINE EAST OF MUNISING. HAVE
MAINTAINED LES ADVISORY FOR KEWEENAW-NRN HOUGHTON COUNTIES THROUGH
12Z BUT DO NOT ANTICIPATE HAVING TO EXTEND ADVISORY.
TONIGHT...A WEAK SHORTWAVE MOVING THROUGH THE NRN PLAINS TODAY WILL
SLIDE JUST SOUTH OF THE CWA...ALTHOUGH THERE COULD BE A LIGHT SNOW
SHOWER BRUSHING SOUTHERN MENOMINEE COUNTY THIS EVENING.
MEANWHILE...LIGHT LAKE EFFECT SNOW WILL BE ONGOING IN THE WEST-
NORTHWEST WIND SNOW BELTS OF NORTHERN LAKE SUPERIOR. WHILE AMOUNTS
WON/T BE ANYTHING TOO SIGNIFICANT INITIALLY THIS EVENING...A
STRONGER SHORTWAVE FROM SCNTRL CANADA WILL DROP SOUTHEAST ACROSS THE
AREA LATE TONIGHT AND WEDNESDAY...BRINGING COLDER 8H TEMPS TO THE
AREA UNDER NORTHWEST WINDS. 8H TEMPS WILL FALL TO -21C OVER EASTERN
LAKE SUPERIOR AND -24C WEST WHICH WILL HELP STEEPEN MID LEVEL LAPSE
RATES AND ALLOW THE INVERSION HEIGHTS TO RISE FROM 4KFT TO AROUND
7KFT BY 12Z WED ESPECIALLY OVER THE WESTERN CWA. THUS...WOULD EXPECT
THE INTENSITY OF THE SNOW SHOWERS TO INCREASE LATE TONIGHT ESPECIALLY
OVER THE WRN CWA AS THE INVERSION HEIGHTS RISE AND MOISTURE DEEPENS
WITH ENHANCEMENT FROM THE SHORTWAVE. DAY SHIFT WILL LIKELY NEED TO
CONSIDER LES ADVISORIES FOR THE NW WIND SNOWBELTS LATE TONIGHT INTO
WEDNESDAY. BLOWING SNOW MAY BECOME MORE OF AN ISSUE ON WEDNESDAY AS
NORTHWEST WINDS WITHIN THE CONVECTIVE LAYER INCREASE IN EXCESS OF 20
KTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM EST TUE FEB 3 2015
AT 12Z WED...A SFC COLD FRONT WILL BE OVER THE SERN CWA AHEAD OF A
SHORTWAVE AND MUCH COLDER AIR MOVING INTO THE AREA. NW WIND LES WILL
BE ONGOING AT THE START OF THE PERIOD AND WILL INTENSIFY THROUGH WED
EVENING. 850MB TEMPS WILL BE -20C TO -25C AT 12Z WED BUT WILL
DECREASE TO -25C TO -30C BETWEEN 18Z WED AND 06Z THU. LOW LEVEL
WINDS WILL BE NEARLY UNIDIRECTIONAL INTO EARLY WED
NIGHT...SUPPORTING MULTI BAND LES STRUCTURE. ONE EXCEPTION IS OVER
ERN UPPER MI...BETWEEN GRAND MARAIS AND WHITEFISH POINT...WHERE THE
LAND BREEZE OFF ONTARIO AND ICE COVERAGE ALONG THE ONTARIO SHORE MAY
LEAD TO A STRONGER MORE DOMINANT BAND. LAKE INDUCED EQUILIBRIUM
LEVELS WILL INCREASE TO AROUND 11KFT WED AFTERNOON AND
EVENING...MEANING HEAVY LES. WITH THE COLD TEMPS...THE CONVECTIVE
LAYER WILL BE OUT OF THE DGZ...SO DENDRITE SIZE WILL BE SMALL AND
SNOW TO LIQUID RATIOS BELOW 20 TO 1. WHILE THIS WILL BE A LIMITATION
FOR SNOWFALL AMOUNTS...THE SMALL FLAKES WILL BE EFFICIENT AT
REDUCING . THEREFORE...THE GREATLY LOWERED VISIBILITIES ARE
ANTICIPATED TO BE THE DOMINANT HAZARD DURING THE EVENT. THE LES WILL
DIMINISH FROM W TO E WED NIGHT BEFORE MOVING OFFSHORE THU MORNING AS
A SFC RIDGE MOVES W TO E THROUGH THE AREA. MIN TEMPS WED NIGHT WILL
RANGE FROM 0F ALONG THE SHORELINES TO
-15F
OVER THE INTERIOR W. WILL CONTINUE TO MENTION THESE COLDER TEMPS IN
THE HWO...BUT LIGHT WINDS WILL LIKELY NOT MEET CRITERIA FOR WIND
CHILL ADVISORIES.
A CLIPPER SHORTWAVE LOOKS TO MOVE NE OF THE CWA THU EVENING INTO THU
NIGHT...BUT MOST OF THE PRECIP ASSOCIATED WITH THE SYSTEM LOOKS TO
STAY NE OF THE CWA. SOME LAKE ENHANCED SNOW COULD RESULT ACROSS THE
NRN KEWEENAW PENINSULA AND MAYBE FAR NERN UPPER MI WITH LIGHT
AMOUNTS IF ANYTHING.
QUITE OF BIT OF UNCERTAINTY WITH SMALLER SCALE DETAILS OF A SERIES
OF SHORTWAVE SAT THROUGH MON. TOO EARLY TO SAY IF SYNOPTIC PRECIP
WILL RESULT IN THE CWA. MODELS DO SHOW N-NE WINDS LATE FRI NIGHT
THROUGH AT LEAST SAT /GFS VEERS WINDS TO A SLY DIRECTION WHILE THE
ECMWF KEEPS NE WINDS INTO MON/. THE GFS SHOWS 850MB TEMPS AROUND
-15C...WHICH WOULD FAVOR HIGHER SNOW TO LIQUID RATIOS AND GREATER
SNOWFALL AMOUNTS DURING THE FAVORABLE FLOW. THE ECMWF SHOWS 850MB
TEMPS OF -20C TO -25C...WHICH WOULD FAVOR LOWER RATIOS BUT STRONGER
LES OVERALL AND ALSO LONGER DURATION OF LES INTO MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 728 AM EST TUE FEB 3 2015
AT KIWD...SW WINDS SHOULD MAINTAIN VFR CONDITIONS UNTIL THIS EVENING
WHEN WINDS BECOME MORE WESTERLY IN THE WAKE OF A TROUGH PASSAGE. LOOK
FOR MVFR CONDITIONS AT THAT TIME WITH SOME LIGHT LAKE EFFECT SNOW
POSSIBLE.
AT KCMX...IFR VSBYS WILL GIVE WAY TO MVFR VSBYS LATER THIS MORNING AS
DOMINANT LAKE EFFECT SNOW BAND SAGS SOUTH OF THE AREA BEING REPLACED
BY WEAKER MULTIBAND LAKE EFFECT SNOW.
AT KSAW...VFR CONDITIONS WILL CONTINUE UNTIL AT LEAST LATE TONIGHT
WHEN WINDS SHIFT FROM WNW TO MORE NW. THE NW WIND COULD BRING IN SOME
HIGH END MVFR CLOUDS LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST TUE FEB 3 2015
A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR TONIGHT INTO
EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO NEAR GALES ARE
POSSIBLE WED...STRONGEST OVER THE EAST HALF. HEAVY FREEZING SPRAY IS
EXPECTED DURING THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE
SUPERIOR. WINDS WILL BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH
THAT CROSSES LATE FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE
TROUGH INTO THE WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
515 AM EST TUE FEB 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST TUE FEB 3 2015
CONCERNS FOCUS ON LES AND ADVISORY HEADLINES OVER THE KEWEENAW
PENINSULA THIS MORNING.
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING ACROSS NRN ONTARIO AND EXITING LAKE
SUPERIOR TO THE NE. AT THE SFC...A TROUGH EXTENDS ACROSS THE SRN
PORTION OF LAKE SUPERIOR AND THE KEWEENAW PENINSULA THIS MORNING.
THIS TROUGH ALONG WITH ENHANCED CONVERGENCE FROM LAND BREEZES OFF
UPPER MI HAS FOCUSED A DOMINANT LES BAND ACROSS THE SRN PORTION OF
LAKE SUPERIOR INTERSECTING THE KEWEENAW PENINSULA BTWN HOUGHTON AND
CALUMET. VISIBILITY BRIEFLY DROPPED TO 1/4 MILE AT KCMX AS THIS BAND
MOVED ACROSS THE AREA SHORTLY AFT MIDNIGHT.
TODAY... WITH THE ONTARIO SHORTWAVE DEPARTING NE OF LAKE SUPERIOR WE
ALREADY MAY BE SEEING SIGNS OF DOMINANT LES BAND WEAKENING OVER SRN
LAKE SUPERIOR AND THE SRN PORTION OF THE KEWEENAW PENINSULA. IT
APPEARS THAT CLOUD TOPS ARE WARMING WHERE THE LES BAND IS LOCATED AS
NOTED ON IR SATELLITE IMAGERY AND REFLECTIVITY RETURNS MAY ALSO BE
WEAKENING SOME WITHIN THE PAST HR. LOOKING AT MODEL FCST SOUNDINGS
WOULD EXPECT WEAKENING TREND TO CONTINUE WITH THIS DOMINANT LES BAND
THROUGH THE MORNING HRS AS INVERSION BASES LOWER FM 5KFT TO 3KFT...
DRYING OCCURS BLO THE INVERSION...AND LOW-LVL CONVERGENCE WEAKENS.
280-290 FLOW LES WILL CONTINUE ACROSS SRN LAKE SUPERIOR INTO NW AND
FAR NE UPPER MI WITH 850 MB TEMPS REMAINING -19/-20C. BUT LOWERING
INVERSION HEIGHTS...DRYING BLO INVERSION AND WEAKENING CONVERGENCE
WILL LIMIT POTENTIAL FOR ADDITIONAL ACCUMULATIONS TO 1 TO 3 INCHES
NW AND 1-2 INCHES ALONG ERN SHORELINE EAST OF MUNISING. HAVE
MAINTAINED LES ADVISORY FOR KEWEENAW-NRN HOUGHTON COUNTIES THROUGH
12Z BUT DO NOT ANTICIPATE HAVING TO EXTEND ADVISORY.
TONIGHT...A WEAK SHORTWAVE MOVING THROUGH THE NRN PLAINS TODAY WILL
SLIDE JUST SOUTH OF THE CWA...ALTHOUGH THERE COULD BE A LIGHT SNOW
SHOWER BRUSHING SOUTHERN MENOMINEE COUNTY THIS EVENING.
MEANWHILE...LIGHT LAKE EFFECT SNOW WILL BE ONGOING IN THE WEST-
NORTHWEST WIND SNOW BELTS OF NORTHERN LAKE SUPERIOR. WHILE AMOUNTS
WON/T BE ANYTHING TOO SIGNIFICANT INITIALLY THIS EVENING...A
STRONGER SHORTWAVE FROM SCNTRL CANADA WILL DROP SOUTHEAST ACROSS THE
AREA LATE TONIGHT AND WEDNESDAY...BRINGING COLDER 8H TEMPS TO THE
AREA UNDER NORTHWEST WINDS. 8H TEMPS WILL FALL TO -21C OVER EASTERN
LAKE SUPERIOR AND -24C WEST WHICH WILL HELP STEEPEN MID LEVEL LAPSE
RATES AND ALLOW THE INVERSION HEIGHTS TO RISE FROM 4KFT TO AROUND
7KFT BY 12Z WED ESPECIALLY OVER THE WESTERN CWA. THUS...WOULD EXPECT
THE INTENSITY OF THE SNOW SHOWERS TO INCREASE LATE TONIGHT ESPECIALLY
OVER THE WRN CWA AS THE INVERSION HEIGHTS RISE AND MOISTURE DEEPENS
WITH ENHANCEMENT FROM THE SHORTWAVE. DAY SHIFT WILL LIKELY NEED TO
CONSIDER LES ADVISORIES FOR THE NW WIND SNOWBELTS LATE TONIGHT INTO
WEDNESDAY. BLOWING SNOW MAY BECOME MORE OF AN ISSUE ON WEDNESDAY AS
NORTHWEST WINDS WITHIN THE CONVECTIVE LAYER INCREASE IN EXCESS OF 20
KTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM EST TUE FEB 3 2015
AT 12Z WED...A SFC COLD FRONT WILL BE OVER THE SERN CWA AHEAD OF A
SHORTWAVE AND MUCH COLDER AIR MOVING INTO THE AREA. NW WIND LES WILL
BE ONGOING AT THE START OF THE PERIOD AND WILL INTENSIFY THROUGH WED
EVENING. 850MB TEMPS WILL BE -20C TO -25C AT 12Z WED BUT WILL
DECREASE TO -25C TO -30C BETWEEN 18Z WED AND 06Z THU. LOW LEVEL
WINDS WILL BE NEARLY UNIDIRECTIONAL INTO EARLY WED
NIGHT...SUPPORTING MULTI BAND LES STRUCTURE. ONE EXCEPTION IS OVER
ERN UPPER MI...BETWEEN GRAND MARAIS AND WHITEFISH POINT...WHERE THE
LAND BREEZE OFF ONTARIO AND ICE COVERAGE ALONG THE ONTARIO SHORE MAY
LEAD TO A STRONGER MORE DOMINANT BAND. LAKE INDUCED EQUILIBRIUM
LEVELS WILL INCREASE TO AROUND 11KFT WED AFTERNOON AND
EVENING...MEANING HEAVY LES. WITH THE COLD TEMPS...THE CONVECTIVE
LAYER WILL BE OUT OF THE DGZ...SO DENDRITE SIZE WILL BE SMALL AND
SNOW TO LIQUID RATIOS BELOW 20 TO 1. WHILE THIS WILL BE A LIMITATION
FOR SNOWFALL AMOUNTS...THE SMALL FLAKES WILL BE EFFICIENT AT
REDUCING . THEREFORE...THE GREATLY LOWERED VISIBILITIES ARE
ANTICIPATED TO BE THE DOMINANT HAZARD DURING THE EVENT. THE LES WILL
DIMINISH FROM W TO E WED NIGHT BEFORE MOVING OFFSHORE THU MORNING AS
A SFC RIDGE MOVES W TO E THROUGH THE AREA. MIN TEMPS WED NIGHT WILL
RANGE FROM 0F ALONG THE SHORELINES TO
-15F
OVER THE INTERIOR W. WILL CONTINUE TO MENTION THESE COLDER TEMPS IN
THE HWO...BUT LIGHT WINDS WILL LIKELY NOT MEET CRITERIA FOR WIND
CHILL ADVISORIES.
A CLIPPER SHORTWAVE LOOKS TO MOVE NE OF THE CWA THU EVENING INTO THU
NIGHT...BUT MOST OF THE PRECIP ASSOCIATED WITH THE SYSTEM LOOKS TO
STAY NE OF THE CWA. SOME LAKE ENHANCED SNOW COULD RESULT ACROSS THE
NRN KEWEENAW PENINSULA AND MAYBE FAR NERN UPPER MI WITH LIGHT
AMOUNTS IF ANYTHING.
QUITE OF BIT OF UNCERTAINTY WITH SMALLER SCALE DETAILS OF A SERIES
OF SHORTWAVE SAT THROUGH MON. TOO EARLY TO SAY IF SYNOPTIC PRECIP
WILL RESULT IN THE CWA. MODELS DO SHOW N-NE WINDS LATE FRI NIGHT
THROUGH AT LEAST SAT /GFS VEERS WINDS TO A SLY DIRECTION WHILE THE
ECMWF KEEPS NE WINDS INTO MON/. THE GFS SHOWS 850MB TEMPS AROUND
-15C...WHICH WOULD FAVOR HIGHER SNOW TO LIQUID RATIOS AND GREATER
SNOWFALL AMOUNTS DURING THE FAVORABLE FLOW. THE ECMWF SHOWS 850MB
TEMPS OF -20C TO -25C...WHICH WOULD FAVOR LOWER RATIOS BUT STRONGER
LES OVERALL AND ALSO LONGER DURATION OF LES INTO MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM EST MON FEB 2 2015
INCREASING MOISTURE LATE TONIGHT WITH THE ARRIVAL OF A SFC TROUGH
WILL ALLOW FOR MVFR CONDITIONS TO RETURN AT KIWD WITH SOME LIGHT LES
EXPECTED LATE TONIGHT.
AT KCMX...IFR VSBYS WILL CONTINUE OVERNIGHT WITH LIFR CONDITIONS
BRIEFLY AT TIMES AS A DOMINANT LES BAND SLOWLY SAGS TO THE SOUTH
ACROSS THE KEWEENAW PENINSULA OVERNIGHT. VSBYS SHOULD IMPROVE TO
MVFR LATE TONIGHT AS WINDS SHIFT MORE NW AND THE DOMINANT LES BAND
MOVES SOUTH OF THE AREA.
AT KSAW...VFR CONDITIONS WILL CONTINUE UNTIL TUE AFTERNOON AS SW
WINDS PREVAIL. THE WIND SWITCHES TO THE W AND ALLOWS MVFR
CLOUDS AND SNOW SHOWERS TO MOVE IN DURING THE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST TUE FEB 3 2015
A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR TONIGHT INTO
EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO NEAR GALES ARE
POSSIBLE WED...STRONGEST OVER THE EAST HALF. HEAVY FREEZING SPRAY IS
EXPECTED DURING THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE
SUPERIOR. WINDS WILL BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH
THAT CROSSES LATE FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE
TROUGH INTO THE WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING
FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
925 AM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 925 PM CST TUE FEB 3 2015
MORNING UPDATE WILL FOCUS ON ONGOING LIGHT SNOW OVER SOUTHEASTERN
NORTH DAKOTA. LATEST MODELED RUC GUIDANCE INCREASES SLIGHTLY THE
QPF OVER SOUTHEASTERN ND AND THE MODELED RAP SNOW RATIOS ARE
SLIGHTLY HIGHER...WHICH MAKES SENSE GIVEN A SLIGHT INCREASE IN
REFLECTIVITIES OVER THE REGION...DUE TO PROXIMITY OF MID LEVEL
FRONTOGENETIC FORCING. HAVE POPULATED QPF AND SNOW RATIO WITH THIS
GUIDANCE AND RERUN SNOW AMOUNTS...WHICH BUMPS SNOWFALLS UP TO THE
ONE AND A HALF TO TWO INCH RANGE. ALSO ADJUSTED POPS TO BRING
LIKELIES INTO VALLEY CITY AND PUSHED SOUTHWARD THE NO SNOW
GRADIENT WITHIN THE VALLEY...AS FAR HAS NOT SEEN ANY PRECIP THE
LAST TWO OBS. NO OTHER CHANGES MADE ON THIS UPDATE.
UPDATE ISSUED AT 630 AM CST TUE FEB 3 2015
THE LIGHT SNOW BAND IS SHIFTING SLOWLY SOUTH WHEN LOOKING AT RADAR
TRENDS AND THE LATEST MESOSCALE MODELS. WE WILL KEEP POPS PRETTY
MUCH THE SAME...BUT LOWER SNOW TOTALS FOR THE FAR SOUTHERN
VALLEY...WITH MOST AREAS LESS THAN AN INCH. THERE COULD BE AN
INCH...PERHAPS 2 IN FAR SOUTHWEST SARGENT COUNTY. OTHERWISE...MOST
AREAS SHOULD BE DRY TODAY WITH A FLURRY PERHAPS AND PLENTY OF CLOUDS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CST TUE FEB 3 2015
THE MAIN CHALLENGE WILL BE SNOW BAND TODAY THAT WILL AFFECT
SOUTHEAST ND INTO ADJACENT PORTIONS OF WC MN. THE GLOBAL MODELS AT
00Z WERE IN GOOD AGREEMENT...ALTHOUGH SOME OF THE LATEST MESOSCALE
MODELS...ESPECIALLY THE HOPWRF ARE SHIFTING THE MAIN SNOW BAND
JUST SOUTH OF THE REGION. THEREFORE...WE WILL HAVE TO MONITOR
WHERE THIS SNOW BAND DEVELOPS THIS MORNING.
FOR TODAY...THE AFOREMENTIONED LIGHT SNOW BAND THAT SHOULD PRODUCE
A BAND OF 1-2 INCHES SHOULD AFFECT THE FAR SOUTHERN FA TODAY.
THERE IS A 6HR WINDOW OF LIFT PER ISENTROPIC/QG FIELDS THAT WILL
QUICKLY MOVE THROUGH IN THE 15-21Z TIME FRAME. THERE IS QUITE A BIT
OF DRY AIR IN PLACE INITIALLY...SO SOME LIFT WILL GO TO SATURATE
COLUMN. WINDS SHOULD BE ON THE LIGHT SIDE WITH THIS SYSTEM...AND WE
WILL MONITOR THIS SNOW THREAT TODAY AND UPDATE AS NEEDED.
TONIGHT...A COLD FRONT WILL MOVE FROM NORTH TO SOUTH AND DANGEROUS
WIND CHILLS MAY DEVELOP AT LEAST IN THE NORTH. SKIES SHOULD CLEAR
OUT WITH THE COLD AIR MOVING IN.
ON WED...IT WILL BE A COLD DAY WITH 490 DECAMETER THICKNESS VALUES IN THE
NORTH. TEMPS WILL STRUGGLE TO REACH 0 IN THE NORTH AND SINGLE
DIGITS ABOVE IN THE SOUTH. WIND CHILLS COULD BE IN ADVISORY
CRITERIA FROM 25-30 BELOW DURING THE MORNING HOURS IN THE NORTH AT LEAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 AM CST TUE FEB 3 2015
FOR WED NIGHT AND THU...EXPECT A DRY PERIOD WITH MID LEVEL TEMPS
WARMING. TEMPS COULD BE STEADY LATER WED NIGHT AND PERHAPS RISE A
BIT IN THE WEST. TEMPS SHOULD RISE ABOVE NORMAL ON THU AHEAD OF
THE NEXT SYSTEM.
FOR THU NIGHT...A CLIPPER TYPE SYSTEM MAY SPREAD SOME LIGHT SNOW
IN THE NORTH WITH STRONG MID LEVEL WAA. THIS COULD BE THE START TO
A BIT MORE ACTIVE PATTERN WITH A STRONG BAROCLINIC ZONE OVER THE REGION.
FRIDAY-MONDAY...A FEW OPPORTUNITIES FOR PRECIP ARE EXPECTED THROUGH
THE WEEKEND. A STRONG LOW-LEVEL THERMAL GRADIENT WILL OSCILLATE
ACROSS THE NORTHERN PLAINS AS SHORTWAVE TROUGHS RIPPLE THROUGH THE
RATHER ZONAL UPPER FLOW. THE TIMING AND LOCATION OF THESE SYSTEMS
WILL IMPACT TEMP TRENDS...AND HAVE STUCK WITH A MODEL BLEND FOR NOW
GIVEN THE LOW DEGREE OF CONFIDENCE WITH SUCH DETAILS. THE SYSTEMS
THAT WILL IMPACT THE REGION WILL HAVE MORE OF A PACIFIC ORIGIN...AND
MORE MOISTURE TO WORK WITH THAN MOST OF THE SYSTEMS RECENTLY. THE
00Z GFS INDICATES PW VALUES NEAR 0.5 INCHES OVER THE AREA ON FRIDAY
AS ONE SYSTEM MOVES THROUGH. RIGHT NOW THE 00Z GFS/ECMWF INDICATE A
BAND OF LIGHT SNOW ASSOCIATED WITH MID-LEVEL FRONTOGENESIS PRIMARILY
AFFECTING NE ND/NW MN...WITH ANOTHER SYSTEM FOR SATURDAY. PLENTY OF
UNCERTAINTY REMAINS WITH THE TRACK AND TIMING OF SYSTEMS IN THIS
TYPE OF PATTERN...THOUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CST TUE FEB 3 2015
EXPECT VFR CIGS TODAY FOR ALL LOCATIONS. WE EXPECT THE MAIN BAND
OF LIGHT SNOW TO FALL JUST TO THE SOUTH AND WEST OF ALL TAF
SITES...ALTHOUGH CAN/T RULE OUT A FLURRY...BUT WILL NOT MENTION
FOR NOW. WINDS SHOULD REMAIN AT OR UNDER 10KTS TODAY...BUT COULD
INCREASE A BIT MORE OVERNIGHT BEHIND A COLD FRONT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
854 AM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 851 AM CST TUE FEB 3 2015
AREA OF SNOW CURRENTLY MOVING THROUGH WESTERN AND CENTRAL NORTH
DAKOTA. THE SNOW IS BEGINNING TO TAPER OFF SOUTHWEST AND WILL BE
DIMINISHING RAPIDLY THIS AFTERNOON. MADE SOME ADJUSTMENTS TO THE
POPS TO ACCOUNT FOR THE TRENDS. LATEST HRRR HAS NEARLY ALL THE SNOW
ENDING BY MID AFTERNOON.
UPDATE ISSUED AT 612 AM CST TUE FEB 3 2015
SNOW CONTINUES OVER THE AREA WITH THE PRIMARY BAND ORIENTATED FROM
WEST CENTRAL INTO SOUTH CENTRAL NORTH DAKOTA. PREVIOUS FORECAST
REFLECTED THIS QUITE WELL...ONLY CHANGE WAS TO INCREASE POPS SOME
ALONG THIS BAND. SNOW IS STILL EXPECTED TO TAPER BY AFTERNOON AS
SURFACE LOW NOW PUSHING INTO FAR NORTHWEST SOUTH DAKOTA CONTINUES
ITS SOUTHEASTERLY TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST TUE FEB 3 2015
THE MAIN FOCUS FOR THE SHORT TERM IS LIGHT SNOW ACCUMULATIONS
BETWEEN 1 AND 3 INCHES (ISOLATED HIGHER AMOUNTS POSSIBLE).
LIGHT SNOW CONTINUES TO OVERSPREAD WESTERN AND CENTRAL NORTH
DAKOTA THIS MORNING AHEAD OF A SURFACE LOW IN EASTERN MONTANA.
RADAR AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE WEST
CENTRAL AND SOUTHERN NORTH DAKOTA WILL SEE THE HEAVIEST AMOUNTS OF
SNOW THIS MORNING AND AFTERNOON. THE 06 NAM AND GFS CONTINUE TO
SHOW WIDESPREAD 2 TO 3 INCHES OF SNOW FROM WATFORD CITY DOWN
THROUGH BISMARCK AND ELLENDALE. SOME ISOLATED LOCATIONS COULD SEE
CLOSER TO 4 INCHES OF SNOW IN SOME OF THE HEAVIER SNOW BANDS.
THE MOST INTENSE AND ORGANIZED SNOW IS EXPECTED TO FALL DURING THE
MORNING HOURS. SNOW WILL COME TO AN END FROM WEST TO EAST BY THE
LATE MORNING AND EARLY AFTERNOON HOURS AS THE LOW PRESSURE CENTER
EXITS TO THE SOUTHEAST. TEMPERATURES TODAY WILL STRUGGLE TO CLIMB
MUCH WITH CLOUDY SKIES EXPECTED ALL DAY. WITH CLEARING SKIES AND
FRESH SNOWPACK TEMPERATURES WILL ONCE AGAIN DROP BELOW ZERO
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CST TUE FEB 3 2015
ACTIVE WEST/NORTHWEST FLOW WILL CONTINUE INTO THE EXTENDED PERIOD
WITH A VARIETY OF DISTURBANCES PUSHING THROUGH.
QUIET WEATHER IS EXPECTED TO START THE PERIOD ON WEDNESDAY INTO
EARLY THURSDAY WITH WEAK RIDGING OVER THE REGION. CHANGES COME FOR
THE END OF THE WEEK AS A PARADE OF MODEST SHORT WAVES START TO MOVE
THROUGH THE AREA AS A BAROCLINIC ZONE SETS UP OVER THE
NORTH...POSSIBLY SAGGING SOUTH BY THE WEEKEND THOUGH MODELS ARE
HAVING SOME TROUBLE WITH THE POSITION OF THIS. THIS WILL BRING
CHANCES FOR PRECIPITATION MAINLY NORTH THROUGH FRIDAY...SPREADING
SOUTHERLY INTO SATURDAY. THE MAIN QUESTION WILL BE PRECIPITATION
TYPES AS MODELS ADVERTISE WARMER TEMPS ALOFT PUSHING MORE OR LESS
INTO THE SOUTHWESTERN HALF OF THE STATE. WITH THIS...HAVE GONE WITH
MENTION OF FREEZING RAIN OVER PARTS OF THE AREA WHERE SURFACE TEMPS
REMAIN SUB FREEZING INTO SATURDAY. BEYOND THAT CONFIDENCE IN MODELS
DETERIORATES AS EC COOLS AND GFS REMAINS WARM SO WILL HOLD OFF OF
FREEZING RAIN MENTION FOR NOW TO SEE HOW MODELS TREND.
PRECIP CHANCES THEN REMAIN OVER VARIOUS PARTS OF THE AREA THROUGH
THE REMAINDER OF THE EXTENDED AS REGION REMAINS IN ACTIVE PATTERN.
SEASONABLY MILD TEMPS EXPECTED SOUTHWEST...CLOSER TO AVERAGE NORTH
CENTRAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 612 AM CST TUE FEB 3 2015
WIDESPREAD MVFR/IFR CONDITIONS IN SNOW WILL CONTINUE ACROSS ALL TAF
SITES THIS MORNING. CONDITIONS WILL IMPROVE TO MVFR/VFR THIS
AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AJ
LONG TERM...JJS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
324 PM EST TUE FEB 3 2015
.SYNOPSIS...
HIGH PRESSURE WILL PUSH OFF THE EAST COAST TONIGHT. AN AREA OF LOW
PRESSURE WILL LIFT INTO NEW ENGLAND LATE WEDNESDAY, PULLING A COLD
FRONT ACROSS THE AREA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
LOW PRESSURE WILL DEVELOP TO OUR EAST ALONG THIS FRONT THURSDAY. HIGH
PRESSURE WILL BUILD TO OUR SOUTH THURSDAY NIGHT INTO FRIDAY. A
FRONTAL BOUNDARY WILL MOVE ACROSS THE AREA SATURDAY NIGHT AND STALL
NEAR THE AREA INTO SUNDAY. A WAVE OF LOW PRESSURE IS EXPECTED TO
MOVE ALONG THE BOUNDARY SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE MID SHIFT FORECAST WITH SOME SLIGHT UPWARD MODIFICATIONS OF
THE TEMPS IS PERFORMING VERY WELL AND THE HIGH CLOUD DISSIPATED AS
MODELED! A BEAUTIFUL DAY....WITH MAX TEMPS ABOUT 10 TO 15 DEGREES
BELOW NORMAL AND A LIGHTER WIND THAN THAT OF LAST EVENING.
TONIGHT...MOSTLY CLEAR TO START WITH RADIATIONAL COOLING EXPECTED
TO SHUT OFF SOMETIME BETWEEN 05Z AND 09Z AS THICK MID CLOUD COVER
DEVELOPS EASTWARD INTO OUR AREA...ESPECIALLY PA AND NJ. THE SOUTHERN
EDGE OF WAA SNOW NOW ENTERING SW WISCONSIN FROM SOUTHERN MINNESOTA
SHOULD RACE EAST ON THE NORTHEAST EDGE OF THE 60KT 700MB JET MODELED INTO
CENTRAL PA BY 12Z WED. ATTENDANT WITH THIS 700MB SPEED MAX IS A MODELED
WSW 850 JET CORE THAT IS MODELED TO BE ASTRIDE THE PA/MD BORDER BY
12Z WED. QUALITATIVELY THE 250 JET DIDN`T SHOW MUCH CONTRIBUTION
TO THE LIFT.
AM EXPECTING SNOW SHOWERS TO MEASURE .1 TO .5 INCHES ALONG AND NW
OF I80 BETWEEN 09Z AND 14Z WEDNESDAY WITH SCATTERED FLURRIES
POSSIBLY DOWN TO KPNE. THIS IS CLOSE TO MULTI MODEL SUPPORT FOR NE
PA AND NW NJ. THE NSSL WRF WAS FURTHER SOUTH...ALMOST TO PHL BY
MORNING AND WE SEE THE CONSERVATIVE RAP IMPLYING FLURRIES DOWN TO
KABE AND KRDG.
FORECAST TEMPS ARE THE COLDER 12Z/3 GFS MOS (NAM WAS NOT AS COLD) AND
WE MAY NEED TO LOWER THESE FORECAST NUMBERS BY 3 OR 4 DEGREES
OVER THE SNOW COVER IN OUR 630 PM EVENING UPDATE...MAINLY ALONG
AND N OF I78.
LIGHT WIND.
OVERALL CONFIDENCE: AVERAGE OR A BIT ABOVE WITH UNCERTAINTY ON THE
SRN EDGE OF THE MEASURABLE SNOW AND THE RADIATIONAL COOLING OVER
SNOWPACK EARLY TONIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
ANY WAA LIGHT SNOW SHOWERS SHOULD QUICKLY END BY 14-15Z AND THEN
CONSIDERABLE SUNSHINE SHOULD DEVELOP MIDDAY WEDNESDAY.
THIS FORECAST IS 50 50 BLEND OF THE 12Z/3 GFS/NAM MOS. THE 12Z
ECMWF 2M TEMPS HAVE COME UP 3 DEGREES FROM THE 00Z/3 CYCLE, SO WE
SEEM TO HAVE A GOOD FIT FOR THE MAX TEMPS TOMORROW (AVERAGE OR A
BIT ABOVE), PROVIDED PARTIAL SUNSHINE DEVELOPS MIDDAY. AM A LITTLE
CAUTIOUS TO EXPRESS HIGH CONFIDENCE IN THIS MAX TEMP FORECAST. A
SOUTHWEST WIND SHOULD GUST 15 TO 20 MPH FOR A TIME WEDNESDAY
AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE AREA OVERNIGHT WEDNESDAY
INTO EARLY THURSDAY MORNING WHILE LOW PRESSURE MOVES INTO NEW
ENGLAND. THERE IS MOSTLY GOOD AGREEMENT WITH THE MODELS MOVING SNOW
ALONG THE FRONT OVERNIGHT WEDNESDAY INTO THURSDAY MORNING AND
MOVING INTO OUR WESTERN AREAS. HOWEVER, THEY ALL BEGIN TO SHRINK THE
SNOW SHIELD SOME AFTER DAYBREAK THURSDAY AS THE SHORT WAVE DEEPENS
AND DIVES MORE ACROSS OUR AREA, DEVELOPING AND STRENGTHENING A LOW
OFF THE COAST. AS THE LOW STRENGTHENS OFFSHORE, THE SNOW OVER THE
LAND MAY BEGIN TO DISSIPATE AND SNOW FOCUSES MORE OFFSHORE AND TO
OUR NORTHEAST. AS OF NOW, THIS FRONT DOES NOT LOOK TO BE A BIG SNOW
PRODUCER, MOSTLY UNDER AN INCH EXCEPT FOR HIGHER ELEVATIONS ACROSS
OUR NORTHWESTERN AREAS WHERE IT WILL LIKELY START SOONER AND SNOW
LONGER. WE EXPECT ANY SNOW TO END BY LATE AFTERNOON AND DRY WEATHER
SHOULD CONTINUE INTO THURSDAY NIGHT. COLD AIR WILL ONCE AGAIN BUILD
INTO THE REGION THURSDAY NIGHT AS THE NORTH-NORTHWEST FLOW WILL PUMP
IN COLD AIR. AS THE LOW STRENGTHENS OFF THE COAST AND MOVES
NORTHWEST, WINDS WILL INCREASE DURING THE DAY AND CONTINUE INTO
THURSDAY NIGHT. WIND GUSTS OF 30-35 MPH ARE POSSIBLE, ESPECIALLY
DURING THE DAY THURSDAY. WITH THE STRONG WINDS, LOW WIND CHILLS WILL
DEVELOP AGAIN, WITH MOST PLACES IN THE SINGLE DIGITS TO BELOW ZERO
WIND CHILLS OVERNIGHT INTO FRIDAY MORNING.
HIGH PRESSURE WILL BUILD TO OUR SOUTH FRIDAY INTO FRIDAY NIGHT, BUT
SHOULD STILL HAVE ENOUGH OF AN IMPACT ON THE AREA TO PROVIDE DRY
WEATHER. BELOW NORMAL TEMPERATURES WILL CONTINUE, ALONG WITH GUSTY
CONDITIONS WITH WIND GUSTS 20-25 MPH DURING THE DAY FRIDAY,
DIMINISHING OVERNIGHT.
ON SATURDAY, A COLD FRONT IS EXPECTED TO SAG DOWN ACROSS THE AREA.
IT IS POSSIBLE SOME LIGHT SNOW MAY ACCOMPANY THE FRONT, MAINLY
ACROSS THE NORTHERN TIER OF THE AREA, AS A SHORT WAVE QUICKLY MOVES
ACROSS THE AREA. HOWEVER, THE MAIN FOCUS OF PRECIPITATION IS
EXPECTED TO BEGIN LATER SATURDAY NIGHT, BUT MOSTLY SUNDAY INTO
MONDAY. THIS FRONTAL BOUNDARY IS EXPECTED TO STALL NEAR OR JUST
SOUTH OF THE AREA, WHILE AN AREA OF LOW PRESSURE DEVELOPS ALONG THE
FAR WESTERN PORTION OF THE FRONT ACROSS THE PLAINS. AS THIS LOW
STRENGTHENS AND MOVES EASTWARD, IT IS EXPECTED TO BRING A PERIOD OF
PRECIPITATION TO THE AREA, STARTING AS EARLY AS SATURDAY NIGHT, BUT
FOCUSING MAINLY SUNDAY AND SUNDAY NIGHT, AND POSSIBLY CONTINUING
INTO MONDAY. DEPENDING ON THE TRACK OF THE STORM AND IF THE FRONT
CAN PUSH BACK NORTHWARD SLIGHTLY, PTYPES COULD BE VARIABLE. NORTH OF
THE LOW/FRONT, PTYPES SHOULD STAY ALL SNOW; SOUTH MAY START AS SNOW,
THEN MIX AND CHANGE TO RAIN, BEFORE ENDING AS SNOW. IN BETWEEN COULD
START AS SNOW, THEN MIX FOR A PERIOD, THEN CHANGE BACK TO SNOW.
IF THE PRECIPITATION CONTINUES INTO MONDAY, IT WOULD LIKELY BE ALL
SNOW BY THAT TIME, BUT SHOULD BE COMING TO AN END AS THE LOW PULLS
TO OUR NORTHEAST. HIGH PRESSURE TRIES TO BUILD INTO THE NORTHEAST
TUESDAY INTO TUESDAY NIGHT, WHICH SHOULD RETURN DRY WEATHER TO THE AREA.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REMAINDER OF TODAY...VFR SCT AOA 15000 FT. NW WIND BACKS TO WSW WITH
GUSTS LESS THAN 15 KT.
TONIGHT...VFR WITH CIGS DEVELOPING LATE AND POSSIBLY LOWERING TO
NEAR 5000 FT IN THE 09Z-12Z TIME FRAME WEDNESDAY MORNING. LIGHT
SOUTHWEST TO SOUTH WIND. BRIEF MVFR CONDS IN SNOW SHOWERS EXPECTED
VCNTY KMPO IN THAT 09Z-12Z TIME FRAME WITH FLURRIES POSSIBLE DOWN
TO KPNE BUT NOT YET CONFIDENTLY FCST.
WEDNESDAY...VFR CIGS BRIEFLY NEAR 5000 FT EARLY IN THE DAY RISING
TO SCT-BKN AOA 10000 FT MIDDAY. LIGHT SOUTHWEST WIND WITH GUSTS 15
TO POSSIBLY 20 KT DURING THE AFTN. CONFIDENCE IS BELOW AVERAGE ON
ANY SNOW WEDNESDAY OR NON VFR CONDITIONS.
OUTLOOK...
WEDNESDAY NIGHT-THURSDAY...VFR EARLY, THEN MVFR/IFR CONDITIONS
POSSIBLE OVERNIGHT INTO THURSDAY WITH SNOW POSSIBLE. GUSTY NORTHWEST
WINDS 25-30 KNOTS.
THURSDAY NIGHT-FRIDAY NIGHT...MOSTLY VFR. ISOLATED SNOW SHOWERS
POSSIBLE DURING THE DAY FRIDAY. GUSTY WEST WINDS 15-20 KNOTS DURING
THE DAY.
SATURDAY...MOSTLY VFR. SNOW SHOWERS POSSIBLE.
SATURDAY NIGHT-SUNDAY...VFR EARLY, THEN DIMINISHING CONDITIONS
OVERNIGHT INTO SUNDAY, BECOMING MVFR/IFR WITH SNOW.
&&
.MARINE...
SCA WAS CANCELED AROUND 1839Z AND NEW SCA ISSUED FOR WED AFTN/EVE.
IT LOOKS TO BE A MARGINAL SCA AT THAT TIME WITH NEUTRAL LAPSE
RATES.
OUTLOOK...
WEDNESDAY NIGHT...SMALL CRAFT EARLY, DIMINISHING TO SUB- SMALL
CRAFT ADVISORY CONDITIONS OVERNIGHT.
THURSDAY-THURSDAY NIGHT...SMALL CRAFT ADVISORY CONDITIONS DEVELOPING
EARLY IN THE DAY CONTINUING INTO THE FIRST HALF OF THURSDAY NIGHT.
POSSIBLE GALE FORCE WINDS; GALE WATCH ISSUED. FREEZING SPRAY POSSIBLE
THURSDAY NIGHT.
FRIDAY-FRIDAY NIGHT...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED.
FREEZING SPRAY POSSIBLE.
SATURDAY...SMALL CRAFT ADVISORY CONDITIONS POSSIBLE.
SATURDAY NIGHT-SUNDAY...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
ANZ430-431-450>455.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM EST WEDNESDAY FOR
ANZ450>455.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON
MARINE...DRAG/ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
224 PM EST TUE FEB 3 2015
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE TENNESSEE AND OHIO VALLEYS WILL
SPREAD INTO OUR REGION TODAY AND TONIGHT BEFORE MOVING OFFSHORE
WEDNESDAY. ELSEWHERE, WEAK LOW PRESSURE WILL ADVANCE FROM THE GREAT
LAKES EARLY WEDNESDAY TO NORTHERN NEW ENGLAND BY WEDNESDAY NIGHT,
SENDING A STRONG COLD FRONT ACROSS OUR AREA. HIGH PRESSURE OVER THE
PLAINS STATES WILL THEN SLOWLY BUILD EASTWARD LATE THURSDAY AND
FRIDAY, FOLLOWED BY A COLD FRONT SETTLING SOUTH THROUGH OUR AREA
SUNDAY. TO CLOSE THE WEEKEND, LOW PRESSURE MAY DEVELOP ALONG EAST
COAST LATE SUNDAY NIGHT TO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MID SHIFT FORECAST WITH SOME SLIGHT UPWARD MODIFICATIONS OF
THE TEMPS IS PERFORMING VERY WELL AND THE HIGH CLOUD DISSIPATED AS
MODELED! A BEAUTIFUL DAY....WITH MAX TEMPS ABOUT 10 TO 15 DEGREES
BELOW NORMAL AND A LIGHTER WIND THAN THAT OF LAST EVENING.
TONIGHT...MOSTLY CLEAR TO START WITH RADIATIONAL COOLING EXPECTED
TO SHUT OFF SOMETIME BETWEEN 05Z AND 09Z AS THICK MID CLOUD COVER
DEVELOPS EASTWARD INTO OUR AREA...ESPECIALLY PA AND NJ. THE SOUTHERN
EDGE OF WAA SNOW NOW ENTERING SW WISCONSIN FROM SOUTHERN MINNESOTA
SHOULD RACE EAST ON THE NORTHEAST EDGE OF THE 60KT 700MB JET MODELED INTO
CENTRAL PA BY 12Z WED. ATTENDANT WITH THIS 700MB SPEED MAX IS A MODELED
WSW 850 JET CORE THAT IS MODELED TO BE ASTRIDE THE PA/MD BORDER BY
12Z WED. QUALITATIVELY THE 250 JET DIDNT SHOW MUCH CONTRIBUTION TO
THE LIFT.
AM EXPECTING SNOW SHOWERS TO MEASURE .1 TO .5 INCHES ALONG AND NW
OF I80 BETWEEN 09Z AND 14Z WEDNESDAY WITH SCATTERED FLURRIES
POSSIBLY DOWN TO KPNE. THIS IS CLOSE TO MULTI MODEL SUPPORT FOR NE
PA AND NW NJ. THE NSSL WRF WAS FURTHER SOUTH...ALMOST TO PHL BY
MORNING AND WE SEE THE CONSERVATIVE RAP IMPLYING FLURRIES DOWN TO
KABE AND KRDG.
FORECAST TEMPS ARE THE COLDER 12Z/3 GFS MOS (NAM WAS NOT AS COLD) AND
WE MAY NEED TO LOWER THESE FORECAST NUMBERS BY 3 OR 4 DEGREES
OVER THE SNOW COVER IN OUR 630 PM EVENING UPDATE...MAINLY ALONG
AND N OF I78.
LIGHT WIND.
OVERALL CONFIDENCE: AVERAGE OR A BIT ABOVE WITH UNCERTAINTY ON THE
SRN EDGE OF THE MEASURABLE SNOW AND THE RADIATIONAL COOLING OVER
SNOWPACK EARLY TONIGHT.
&&
.SHORT TERM /WEDNESDAY/...
ANY WAA LIGHT SNOW SHOWERS SHOULD QUICKLY END BY 14-15Z AND THEN
CONSIDERABLE SUNSHINE SHOULD DEVELOP MIDDAY WEDNESDAY.
THIS FORECAST IS 50 50 BLEND OF THE 12Z/3 GFS/NAM MOS. THE 12Z
ECMWF 2M TEMPS HAVE COME UP 3 DEGREES FROM THE 00Z/3 CYCLE, SO WE
SEEM TO HAVE A GOOD FIT FOR THE MAX TEMPS TOMORROW (AVERAGE OR A
BIT ABOVE), PROVIDED PARTIAL SUNSHINE DEVELOPS MIDDAY. AM A LITTLE
CAUTIOUS TO EXPRESS HIGH CONFIDENCE IN THIS MAX TEMP FORECAST. A
SOUTHWEST WIND SHOULD GUST 15 TO 20 MPH FOR A TIME WEDNESDAY
AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THROUGH THE LONG TERM PERIOD, A SOMEWHAT ACTIVE AND UNSETTLED
PATTERN IS EXPECTED TO CONTINUE. A WEAK AREA OF LOW PRESSURE OVER
THE GREAT LAKES EARLY WEDNESDAY MORNING IS FORECAST TO PROGRESS
EAST, REACHING NORTHERN NEW ENGLAND BY LATER WEDNESDAY NIGHT. IT
ASSOCIATED STRONG COLD FRONT IS EXPECTED TO CROSS OUR REGION
WEDNESDAY NIGHT TO EARLY MORNING THURSDAY. THE BULK OF ANY
STEADIER PRECIP LOOKS TO HOLD OFF UNTIL LATER WEDNESDAY NIGHT AND
INTO THURSDAY. OF NOTE, THE WEDNESDAY OVERNIGHT THROUGH THURSDAY
TIMEFRAME WILL CONTINUE TO BE MONITORED FOR POSSIBLE PHASING OF
THE NORTHERN STREAM AND SOUTHERN STREAM, WITH LOW PRESSURE
DEVELOPMENT ALONG THE DEPARTING COLD FRONT BOUNDARY. THIS
SOLUTION, WHICH IS MOSTLY SUPPORTED BY THE ECMWF AND ITS
ENSEMBLES, MAINLY LOOKS TO BE MORE OF AN OUTLIER AT THIS TIME AND
WAS NOT FACTORED IN MUCH TO THE FORECAST. WHILE CONTINUITY WAS
MAINTAINED FOR THE MOST PART, SOME ADJUSTMENTS WERE MADE TO POPS
AND TIMING THROUGH THIS PERIOD. AT THIS TIME, ANY SNOW
ACCUMULATION FROM WEDNESDAY NIGHT TO THURSDAY LOOKS TO BE LIGHT.
BEHIND THIS DEPARTING SYSTEM THURSDAY NIGHT, ANOTHER NOTICEABLE PUSH
OF FRIGID AIR IS EXPECTED ON NORTHWEST WINDS, AND AS TEMPERATURES
DROP THROUGH THE NIGHT, WIND CHILL VALUES AROUND ZERO TO POSSIBLY
BELOW ZERO WILL BE FELT. IN FACT, WIND CHILL ADVISORIES MAY NEED TO
BE CONSIDERED FOR OUR NORTHERN ZONES. AT THIS TIME, MINIMUM
TEMPERATURES LOOK TO RANGE FROM THE SINGLE DIGITS BELOW ZERO IN THE
POCONOS TO THE SINGLE DIGITS ABOVE ZERO AND LOWER TEENS ELSEWHERE.
WITH INCOMING HIGH PRESSURE FRIDAY, A RELATIVELY QUIET BUT COLD DAY
IS EXPECTED WITH NORTHWEST TO WEST WINDS THROUGH THE DAY AND MAXIMUM
TEMPERATURES WELL BELOW AVERAGE, AS HIGHS MOSTLY RANGE FROM TEENS IN
THE NORTH TO THE MID/UPPER 20S IN SOUTHERN NJ AND THE DELMARVA.
THROUGH THE REMAINDER OF THE LONG TERM PERIOD THEN, WE MOSTLY
FOLLOWED A BLEND OF WPC GUIDANCE WITH CONTINUITY AS MODEL SOLUTIONS
TEND TO DIVERGE MORE. THE PREVIOUSLY MENTIONED HIGH PRESSURE LOOKS
TO PUSH FARTHER SOUTHEAST AND AWAY FROM THE REGION LATER FRIDAY
NIGHT THROUGH SATURDAY. BY SUNDAY, A COLD FRONT IS EXPECTED TO
SETTLE SOUTH THROUGH THE REGION, AND WE HAVE KEPT SOME HIGHER POPS
IN PICTURE FOR SUNDAY TO SUNDAY NIGHT, WITH TEMPS BEING COLD ENOUGH
TO MAINLY SUPPORT SNOW. FROM HERE, THERE MUCH UNCERTAINTY AT THE END
OF THE LONG TERM PERIOD AS THERE IS SOME POTENTIAL FOR AN EAST COAST
LOW PRESSURE TO DEVELOP ALONG THE DEPARTING FRONTAL BOUNDARY SUNDAY
NIGHT INTO MONDAY, WITH A NOTICEABLE MID-LEVEL TROUGH ALSO DIGGING
TO THE EAST COAST. CONFIDENCE IS BELOW AVERAGE IN THE TIMING AND
DEVELOPMENT OF THIS POTENTIAL SYSTEM AS THERE ARE NOTICEABLE
DIFFERENCES BETWEEN THE GFS, ECMWF, AND OTHERS WITH REGARDS TO THE
STRENGTH OF THE MID-LEVEL TROUGH AND THE PLACEMENT OF THE DEVELOPING
LOW PRESSURE. FOR NOW, WE MAINLY WENT WITH A BLEND OF WPC GUIDANCE
AND CONTINUITY FOR TEMPS/WINDS/POPS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
REMAINDER OF TODAY...VFR SCT AOA 15000 FT. NW WIND BACKS TO WSW WITH
GUSTS LESS THAN 15 KT.
TONIGHT...VFR WITH CIGS DEVELOPING LATE AND POSSIBLY LOWERING TO
NEAR 5000 FT IN THE 09Z-12Z TIME FRAME WEDNESDAY MORNING. LIGHT
SOUTHWEST TO SOUTH WIND. BRIEF MVFR CONDS IN SNOW SHOWERS EXPECTED
VCNTY KMPO IN THAT 09Z-12Z TIME FRAME WITH FLURRIES POSSIBLE DOWN
TO KPNE BUT NOT YET CONFIDENTLY FCST.
WEDNESDAY...VFR CIGS BRIEFLY NEAR 5000 FT EARLY IN THE DAY RISING
TO SCT-BKN AOA 10000 FT MIDDAY. LIGHT SOUTHWEST WIND WITH GUSTS 15
TO POSSIBLY 20 KT DURING THE AFTN. CONFIDENCE IS BELOW AVERAGE ON
ANY SNOW WEDNESDAY OR NON VFR CONDITIONS.
OUTLOOK...
THURSDAY...SOME POSSIBLE SUB-VFR IN LIGHT SNOW DURING THE DAYTIME,
OTHERWISE VFR CONDITIONS.
FRIDAY...VFR CONDITIONS ARE EXPECTED.
SATURDAY...MAINLY VFR CONDITIONS ARE EXPECTED, WITH CEILINGS AT OR
ABOVE 6000 FEET. SOME POSSIBLE SUB-VFR FOR NORTHERN TERMINALS IN
LIGHT SNOW.
&&
.MARINE...
SCA WAS CANCELED AROUND 1839Z AND NEW SCA ISSUED FOR WED AFTN/EVE.
IT LOOKS TO BE A MARGINAL SCA AT THAT TIME WITH NEUTRAL LAPSE
RATES.
OUTLOOK...
WEDNESDAY NIGHT AND THURSDAY...A STRONG COLD FRONT CROSSING THE
AREA LATER WEDNESDAY NIGHT AND THURSDAY WILL YIELD A BETTER
OPPORTUNITY FOR WIND GUSTS INTO THE 25 TO 30 KNOT RANGE. MODERATE
FREEZING SPRAY MAY DEVELOP THEN LATER THURSDAY NIGHT.
FRIDAY...SCA CONDITIONS MAY LAST INTO FRIDAY MORNING. IN ADDITION,
FREEZING SPRAY IS POSSIBLE.
SATURDAY...MARGINAL SCA CONDITIONS ARE POSSIBLE WITH WIND GUSTS
APPROACHING 25 KNOTS AND SEAS NEARING 5 FEET, ESPECIALLY FOR THE
COASTAL WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM EST WEDNESDAY FOR
ANZ450>455.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...DRAG 223
SHORT TERM...DRAG 223
LONG TERM...KLINE
AVIATION...DRAG 223
MARINE...DRAG 223
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
436 PM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 434 PM CST TUE FEB 3 2015
A QUICK UPDATE SENT TO REFINE POPS TO ONLY THE NORTHEASTERN
COUNTIES...WHERE FGEN FORCING WILL CONTINUE FOR ANOTHER HOUR OR SO
BEFORE ENDING RAPIDLY AS IT HAS DONE UPSTREAM IN NORTHEAST IOWA
THIS PAST HOUR. OTHERWISE...MINOR HOURLY TEMP UPDATES THROUGH
ROUTINE PROCEDURES SENT. NO CHANGES MADE TO OVERNIGHT SNOWS
ENTERING THE FAR SOUTHWEST TOWARD 12Z.
ERVIN
&&
.SYNOPSIS...
ISSUED AT 330 PM CST TUE FEB 3 2015
12Z UA ANALYSIS HAS AN 850MB WARM FRONT ASSOCIATED WITH AN UPPER
LEVEL DISTURBANCE FROM SOUTH DAKOTA THROUGH WESTERN IOWA AND INTO
NORTHEAST MISSOURI. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON
HAVE A BAND OF WAA SNOW FROM EASTERN MINNESOTA INTO NORTHERN
ILLINOIS.
18Z SFC ANALYSIS HAS A WEAK LOW SOUTH OF K9V9 WITH A WARM FRONT
RUNNING ROUGHLY ALONG THE MISSOURI RIVER. WEAK TROFS WERE AHEAD OF
THE WARM FRONT ACROSS EASTERN IOWA INTO ILLINOIS. DEW POINTS WERE IN
THE SINGLE DIGITS ACROSS THE UPPER MIDWEST WITH TEENS AND 20S ACROSS
THE REMAINDER OF THE MIDWEST. A NARROW TONGUE OF 30 DEGREE DEW
POINTS RAN FROM THE SOUTHERN PLAINS INTO WESTERN NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM CST TUE FEB 3 2015
BASED ON RADAR TRENDS AND EXTRAPOLATION OF SAID TRENDS. THE FORCING
CREATING THE SNOW GENERALLY LINES UP WITH THE ADVECTION IN THE
800-825 MB LAYER. RAP TRENDS INDICATE THIS CONVERGENCE/FORCING WILL
CLEAR THE NORTHERN AREAS EARLY THIS EVENING WITH MAINLY QUIET
CONDITIONS BY MIDNIGHT.
THUS WILL KEEP THE HIGH POPS GOING NORTH OF HIGHWAY 30 THROUGH LATE
AFTERNOON WITH POPS TAPERING OFF QUICKLY BEHIND THE BAND. AREAS
GENERALLY ALONG/SOUTH OF I-80 WITH SEE EITHER NO SNOW OR JUST A FEW
FLURRIES FROM A PASSING MID LEVEL CLOUD DECK.
QUIET CONDITIONS WILL BE SEEN ACROSS THE AREA AFTER MIDNIGHT IN THE
BRIEF QUIET AHEAD OF THE NEXT CLIPPER TYPE STORM SYSTEM. SNOW SHOULD
BE CLOSE TO THE WESTERN AREAS JUST PRIOR TO SUNRISE WEDNESDAY.
ON WEDNESDAY...RAPID SATURATION OF THE ATMOSPHERE OCCURS DURING THE
MORNING AS MOISTURE AND STRONG FORCING FROM THE STORM SYSTEM SURGES
INTO THE AREA. SNOW WILL QUICKLY BREAK OUT DURING THE MORNING FOR
AREAS ALONG/SOUTH OF I-80. THE FORCING/MOISTURE BEGINS SHIFTING EAST
OF THE AREA WEDNESDAY AFTERNOON SO THERE SHOULD BE A FAIRLY QUICK
SHUT DOWN OF THE SNOW FOR MOST AREAS FROM WEST TO EAST DURING THE
AFTERNOON.
AREAS GENERALLY SOUTH OF AN OTTUMWA TO GALESBURG LINE WILL CONTINUE
TO SEE SNOW PERSISTING UNTIL MID OR LATE AFTERNOON FOLLOWED BY A
FAIRLY RAPID END TO THE SNOW.
AS FOR AMOUNTS...A DUSTING MAY OCCUR BETWEEN I-80 AND HIGHWAY 30.
AREAS ALONG AND IMMEDIATELY SOUTH OF I-80 SHOULD SEE ROUGHLY AN INCH
OF ACCUMULATION. AREAS ALONG/SOUTH OF AN OTTUMWA TO GALESBURG LINE
SHOULD SEE 2 TO 3 INCHES OF SNOW.
RIGHT NOW THERE ARE NO PLANS ON ISSUING ANY WINTER WEATHER HEADLINES
FOR THE WEDNESDAY STORM SYSTEM. THE HWO AND WEATHER STORY WILL BE
UPDATED TO INCREASE THE AWARENESS OF THE COMING SNOW. ..08..
.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 330 PM CST TUE FEB 3 2015
WEDNESDAY NIGHT THROUGH FRIDAY...1037+ MB CANADIAN RIDGE STILL ON
TRACK TO DUMP DOWN THE PLAINS/UPPER TO MID MS RVR VALLEY WED NIGHT
INTO THU MORNING WITH A SCOURING EFFECT ON CLOUDS/ANY LINGERING
PRECIP. 12Z MODELS GENERALLY AGREE ON COLD PROFILES SUCH AS -13C TO
-18C H925 MB TEMPS OVER SUBSTANTIAL SNOWPACK FOR A TEMP BOTTOM-OUT
AS LONG AS SFC WINDS DECOUPLE AND SKIES REMAIN LARGELY CLEAR. WITH
INCOMING SFC RIDGE PRESSURE GRADIENT POSSIBLY MAINTAINING SFC WINDS
OF 5-10 MPH INTO THU MORNING...AS WELL AS A POSSIBLE CIRRUS SHIELD
ASSOCIATED WITH UPPER JET STREAKING SOUTHEASTWARD ACRS THE MO RVR
VALLEY DOWN INTO THE LOWER MS RVR VALLEY...BOTH THESE IDEAL
RADIATE-OUT PARAMETERS MAY NOT BE SO IDEAL. BUT WILL BANK ON THE DEEP
SNOW COVER AND SFC WINDS TO DECOUPLE LATE AND KEEP MUCH OF THE CWA
REACHING LOWS OF -8 TO -12F ALONG AND NORTH OF I80...TO -3 TO -9F TO
THE SOUTH. EVEN LIGHT WINDS OF 3-6 MPH WILL STILL GENERATE -15 TO
-25F WIND CHILLS ACRS THE NORTHERN 2/3S OF THE CWA AFTER MIDNIGHT
INTO MID THU MORNING. THUS AN ADVISORY MAY HAVE TO BE EVENTUALLY
ISSUED.
RETURN FLOW STREAMS BACK NORTHWARD BEHIND PASSING RIDGE AXIS FOR
LATE THU AFTERNOON HIGHS. DEPENDING ON WIND SPEED DROP OFF AFTER
SUNSET THU EVENING...THU NIGHT LOWS MAY OCCUR FROM SUNSET THROUGH
9-10 PM CST OR SO...BEFORE DOING A STEADY TO SLOW RISE TREND INTO
FRI MORNING. THE LATEST MEDIUM RANGE MODELS CONTINUE TO SUGGEST A
DAMPENING NORTHWEST FLOW PATTERN WITH THE CLIPPER STORM TRACK AND
LLVL BAROCLINICITY GETTING SHUNTED TO THE NORTHWEST/NORTH ACRS THE
NORTHERN PLAINS INTO THE GRT LKS THROUGH THE START OF THE WEEKEND.
BULK OF THE SOLUTION SUGGEST FRI TO BE A WARM SECTOR DAY SOUTH OF
A PASSING WAVE ACRS MN INTO WI...THE WARM DRAW UP ACRS THE CWA
WOULD PRODUCE TEMPS WELL INTO THE 40S IF IT WERE NOT FOR THE SNOW
COVER...WILL PLAY IT CONSERVATIVELY WITH TEMPS MORE IN THE 30S
ALTHOUGH A 40 STILL POSSIBLE IN THE SOUTH. SFC WAVE AND FRONT SLIP
THRU THE AREA FRI NIGHT...BUT POST-LOW COOL DOWN NOTHING EXTREME.
WITH SOME SNOW MELT JUICING THE SFC LAYER ON FRI...ANY SFC WINDS
GOING LIGHT OR LIGHT CONVERGENT MAY PRODUCE SOME FOG IF ANY
PERIODS OF CLEAR SKIES OCCUR.
SATURDAY AND SUNDAY...LATEST MODEL TRENDS SUGGEST FLATTENED FLOW TO
USHER THE NEXT WAVE/WHICH IS PARTIALLY RESPONSIBLE FOR THE WESTERN
RIDGE DAMPENING/ ACRS THE NORTH HALF TO THIRD OF THE CWA SAT NIGHT
INTO SUNDAY MORNING. PRE-SYSTEM WARMING MAY MAKE FOR MORE UPPER 30S
TO LOWER 40S SOUTH OF I80 FOR SAT...AND CONTINUED SNOW MELTING.
WITH CONVERGENT RETURN FLOW ALONG ANOTHER WARM FRONT ASSOCIATED WITH
THE SYSTEM...FOG COULD LINGER WELL INTO SAT ALONG THE BOUNDARY. FOG
AND LOW STRATUS MAY LIMIT TEMPS SAT TO THE LOWER 30S NORTH OF I80...
WILL HAVE TO KEEP DRIZZLE IN MIND IF THIS OCCURS. BULK OF THE MORE
SUBSTANTIAL DEF ZONE SNOWS WOULD STAY ACRS THE DAKOTAS...MN INTO
WI/LOWER MI WITH THE CURRENT CLIPPER TRACK FRO SAT NIGHT INTO
SUNDAY. BUT SOME PRECIP WOULD CLIP THE FAR NORTHERN CWA...SAT
EVENING A WINTERY MIX COULD BE POSSIBLE NORTH OF HWY 30...WITH WRAP
AROUND SNOW SHOWERS...OR RAIN-SNOW SHOWER MIX THEN POSSIBLE DOWN TO
HWY 30 OR SOUTH TO I80 ON SUNDAY IN THE SYSTEM/S WAKE. WILL KEEP
GENERAL BLEND OF POPS AND MAINLY SNOW WORDING FOR NOW WITH THE
UNCERTAINTY OVER THE WEEKEND AND THE POSSIBILITY OF THE SYSTEM
TRACKING FURTHER SOUTH AGAIN IN LATER MODEL RUNS. FOG POSSIBLE AGAIN
SAT NIGHT IN VCNTY OF CYCLONIC FLOW AROUND THE SFC LOW AND ANY
ASSOCIATED BOUNDARY.
NEXT MONDAY AND TUESDAY...ENSEMBLES AND LONGER RANGE TRENDS SUGGEST
A BRIEF CHILL DOWN MONDAY BEHIND WHAT EVER SYSTEM CAN MOVE ACRS THE
REGION SAT-SUN...WITH PACIFIC JET ENERGY THEN BILLOWING IT/S WAY
EASTWARD FOR A MEAN FLOW FLATTEN-OUT AGAIN INTO MID NEXT WEEK. THIS
WOULD ALSO BRING A REBOUND IN TEMPS AGAIN AS WELL AS HIGHER DPTS FROM
THE SOUTH EATING AT THE SNOW COVER. WAA TYPE PRECIP WOULD ALSO BE
POSSIBLE IN OR NEAR THE CWA TUE INTO NEXT WED...BUT OF COURSE TIMING
AND AREAL EXTENT TOO DISTANT TO PLACE IN THE FCST AT THIS POINT.
..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1133 AM CST TUE FEB 3 2015
A WEAK STORM SYSTEM WILL MOVE INTO THE GREAT LAKES REGION THIS
AFTERNOON AND TONIGHT. VFR CONDITIONS AT KDBQ WILL DETERIORATE TO
IFR WITH SNOW THROUGH 00Z/04 AND THEN IMPROVE TO MVFR AFT 00Z/04.
KCID/KMLI/KBRL SHOULD REMAIN VFR THROUGH 09Z/04 AND THEN SLOWLY
DETERIORATE TO MVFR CONDITIONS AFT 09Z/04. ANOTHER STORM SYSTEM
WILL IMPACT EASTERN IOWA AND NORTHERN ILLINOIS AFT 12Z/04.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 PM CST TUE FEB 3 2015
.SYNOPSIS...
ISSUED AT 330 PM CST TUE FEB 3 2015
12Z UA ANALYSIS HAS AN 850MB WARM FRONT ASSOCIATED WITH AN UPPER
LEVEL DISTURBANCE FROM SOUTH DAKOTA THROUGH WESTERN IOWA AND INTO
NORTHEAST MISSOURI. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON
HAVE A BAND OF WAA SNOW FROM EASTERN MINNESOTA INTO NORTHERN
ILLINOIS.
18Z SFC ANALYSIS HAS A WEAK LOW SOUTH OF K9V9 WITH A WARM FRONT
RUNNING ROUGHLY ALONG THE MISSOURI RIVER. WEAK TROFS WERE AHEAD OF
THE WARM FRONT ACROSS EASTERN IOWA INTO ILLINOIS. DEW POINTS WERE IN
THE SINGLE DIGITS ACROSS THE UPPER MIDWEST WITH TEENS AND 20S ACROSS
THE REMAINDER OF THE MIDWEST. A NARROW TONGUE OF 30 DEGREE DEW
POINTS RAN FROM THE SOUTHERN PLAINS INTO WESTERN NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM CST TUE FEB 3 2015
BASED ON RADAR TRENDS AND EXTRAPOLATION OF SAID TRENDS. THE FORCING
CREATING THE SNOW GENERALLY LINES UP WITH THE ADVECTION IN THE
800-825 MB LAYER. RAP TRENDS INDICATE THIS CONVERGENCE/FORCING WILL
CLEAR THE NORTHERN AREAS EARLY THIS EVENING WITH MAINLY QUIET
CONDITIONS BY MIDNIGHT.
THUS WILL KEEP THE HIGH POPS GOING NORTH OF HIGHWAY 30 THROUGH LATE
AFTERNOON WITH POPS TAPERING OFF QUICKLY BEHIND THE BAND. AREAS
GENERALLY ALONG/SOUTH OF I-80 WITH SEE EITHER NO SNOW OR JUST A FEW
FLURRIES FROM A PASSING MID LEVEL CLOUD DECK.
QUIET CONDITIONS WILL BE SEEN ACROSS THE AREA AFTER MIDNIGHT IN THE
BRIEF QUIET AHEAD OF THE NEXT CLIPPER TYPE STORM SYSTEM. SNOW SHOULD
BE CLOSE TO THE WESTERN AREAS JUST PRIOR TO SUNRISE WEDNESDAY.
ON WEDNESDAY...RAPID SATURATION OF THE ATMOSPHERE OCCURS DURING THE
MORNING AS MOISTURE AND STRONG FORCING FROM THE STORM SYSTEM SURGES
INTO THE AREA. SNOW WILL QUICKLY BREAK OUT DURING THE MORNING FOR
AREAS ALONG/SOUTH OF I-80. THE FORCING/MOISTURE BEGINS SHIFTING EAST
OF THE AREA WEDNESDAY AFTERNOON SO THERE SHOULD BE A FAIRLY QUICK
SHUT DOWN OF THE SNOW FOR MOST AREAS FROM WEST TO EAST DURING THE
AFTERNOON.
AREAS GENERALLY SOUTH OF AN OTTUMWA TO GALESBURG LINE WILL CONTINUE
TO SEE SNOW PERSISTING UNTIL MID OR LATE AFTERNOON FOLLOWED BY A
FAIRLY RAPID END TO THE SNOW.
AS FOR AMOUNTS...A DUSTING MAY OCCUR BETWEEN I-80 AND HIGHWAY 30.
AREAS ALONG AND IMMEDIATELY SOUTH OF I-80 SHOULD SEE ROUGHLY AN INCH
OF ACCUMULATION. AREAS ALONG/SOUTH OF AN OTTUMWA TO GALESBURG LINE
SHOULD SEE 2 TO 3 INCHES OF SNOW.
RIGHT NOW THERE ARE NO PLANS ON ISSUING ANY WINTER WEATHER HEADLINES
FOR THE WEDNESDAY STORM SYSTEM. THE HWO AND WEATHER STORY WILL BE
UPDATED TO INCREASE THE AWARENESS OF THE COMING SNOW. ..08..
.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 330 PM CST TUE FEB 3 2015
WEDNESDAY NIGHT THROUGH FRIDAY...1037+ MB CANADIAN RIDGE STILL ON
TRACK TO DUMP DOWN THE PLAINS/UPPER TO MID MS RVR VALLEY WED NIGHT
INTO THU MORNING WITH A SCOURING EFFECT ON CLOUDS/ANY LINGERING
PRECIP. 12Z MODELS GENERALLY AGREE ON COLD PROFILES SUCH AS -13C TO
-18C H925 MB TEMPS OVER SUBSTANTIAL SNOWPACK FOR A TEMP BOTTOM-OUT
AS LONG AS SFC WINDS DECOUPLE AND SKIES REMAIN LARGELY CLEAR. WITH
INCOMING SFC RIDGE PRESSURE GRADIENT POSSIBLY MAINTAINING SFC WINDS
OF 5-10 MPH INTO THU MORNING...AS WELL AS A POSSIBLE CIRRUS SHIELD
ASSOCIATED WITH UPPER JET STREAKING SOUTHEASTWARD ACRS THE MO RVR
VALLEY DOWN INTO THE LOWER MS RVR VALLEY...BOTH THESE IDEAL
RADIATE-OUT PARAMETERS MAY NOT BE SO IDEAL. BUT WILL BANK ON THE DEEP
SNOW COVER AND SFC WINDS TO DECOUPLE LATE AND KEEP MUCH OF THE CWA
REACHING LOWS OF -8 TO -12F ALONG AND NORTH OF I80...TO -3 TO -9F TO
THE SOUTH. EVEN LIGHT WINDS OF 3-6 MPH WILL STILL GENERATE -15 TO
-25F WIND CHILLS ACRS THE NORTHERN 2/3S OF THE CWA AFTER MIDNIGHT
INTO MID THU MORNING. THUS AN ADVISORY MAY HAVE TO BE EVENTUALLY
ISSUED.
RETURN FLOW STREAMS BACK NORTHWARD BEHIND PASSING RIDGE AXIS FOR
LATE THU AFTERNOON HIGHS. DEPENDING ON WIND SPEED DROP OFF AFTER
SUNSET THU EVENING...THU NIGHT LOWS MAY OCCUR FROM SUNSET THROUGH
9-10 PM CST OR SO...BEFORE DOING A STEADY TO SLOW RISE TREND INTO
FRI MORNING. THE LATEST MEDIUM RANGE MODELS CONTINUE TO SUGGEST A
DAMPENING NORTHWEST FLOW PATTERN WITH THE CLIPPER STORM TRACK AND
LLVL BAROCLINICITY GETTING SHUNTED TO THE NORTHWEST/NORTH ACRS THE
NORTHERN PLAINS INTO THE GRT LKS THROUGH THE START OF THE WEEKEND.
BULK OF THE SOLUTION SUGGEST FRI TO BE A WARM SECTOR DAY SOUTH OF
A PASSING WAVE ACRS MN INTO WI...THE WARM DRAW UP ACRS THE CWA
WOULD PRODUCE TEMPS WELL INTO THE 40S IF IT WERE NOT FOR THE SNOW
COVER...WILL PLAY IT CONSERVATIVELY WITH TEMPS MORE IN THE 30S
ALTHOUGH A 40 STILL POSSIBLE IN THE SOUTH. SFC WAVE AND FRONT SLIP
THRU THE AREA FRI NIGHT...BUT POST-LOW COOL DOWN NOTHING EXTREME.
WITH SOME SNOW MELT JUICING THE SFC LAYER ON FRI...ANY SFC WINDS
GOING LIGHT OR LIGHT CONVERGENT MAY PRODUCE SOME FOG IF ANY
PERIODS OF CLEAR SKIES OCCUR.
SATURDAY AND SUNDAY...LATEST MODEL TRENDS SUGGEST FLATTENED FLOW TO
USHER THE NEXT WAVE/WHICH IS PARTIALLY RESPONSIBLE FOR THE WESTERN
RIDGE DAMPENING/ ACRS THE NORTH HALF TO THIRD OF THE CWA SAT NIGHT
INTO SUNDAY MORNING. PRE-SYSTEM WARMING MAY MAKE FOR MORE UPPER 30S
TO LOWER 40S SOUTH OF I80 FOR SAT...AND CONTINUED SNOW MELTING.
WITH CONVERGENT RETURN FLOW ALONG ANOTHER WARM FRONT ASSOCIATED WITH
THE SYSTEM...FOG COULD LINGER WELL INTO SAT ALONG THE BOUNDARY. FOG
AND LOW STRATUS MAY LIMIT TEMPS SAT TO THE LOWER 30S NORTH OF I80...
WILL HAVE TO KEEP DRIZZLE IN MIND IF THIS OCCURS. BULK OF THE MORE
SUBSTANTIAL DEF ZONE SNOWS WOULD STAY ACRS THE DAKOTAS...MN INTO
WI/LOWER MI WITH THE CURRENT CLIPPER TRACK FRO SAT NIGHT INTO
SUNDAY. BUT SOME PRECIP WOULD CLIP THE FAR NORTHERN CWA...SAT
EVENING A WINTERY MIX COULD BE POSSIBLE NORTH OF HWY 30...WITH WRAP
AROUND SNOW SHOWERS...OR RAIN-SNOW SHOWER MIX THEN POSSIBLE DOWN TO
HWY 30 OR SOUTH TO I80 ON SUNDAY IN THE SYSTEM/S WAKE. WILL KEEP
GENERAL BLEND OF POPS AND MAINLY SNOW WORDING FOR NOW WITH THE
UNCERTAINTY OVER THE WEEKEND AND THE POSSIBILITY OF THE SYSTEM
TRACKING FURTHER SOUTH AGAIN IN LATER MODEL RUNS. FOG POSSIBLE AGAIN
SAT NIGHT IN VCNTY OF CYCLONIC FLOW AROUND THE SFC LOW AND ANY
ASSOCIATED BOUNDARY.
NEXT MONDAY AND TUESDAY...ENSEMBLES AND LONGER RANGE TRENDS SUGGEST
A BRIEF CHILL DOWN MONDAY BEHIND WHAT EVER SYSTEM CAN MOVE ACRS THE
REGION SAT-SUN...WITH PACIFIC JET ENERGY THEN BILLOWING IT/S WAY
EASTWARD FOR A MEAN FLOW FLATTEN-OUT AGAIN INTO MID NEXT WEEK. THIS
WOULD ALSO BRING A REBOUND IN TEMPS AGAIN AS WELL AS HIGHER DPTS FROM
THE SOUTH EATING AT THE SNOW COVER. WAA TYPE PRECIP WOULD ALSO BE
POSSIBLE IN OR NEAR THE CWA TUE INTO NEXT WED...BUT OF COURSE TIMING
AND AREAL EXTENT TOO DISTANT TO PLACE IN THE FCST AT THIS POINT.
..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1133 AM CST TUE FEB 3 2015
A WEAK STORM SYSTEM WILL MOVE INTO THE GREAT LAKES REGION THIS
AFTERNOON AND TONIGHT. VFR CONDITIONS AT KDBQ WILL DETERIORATE TO
IFR WITH SNOW THROUGH 00Z/04 AND THEN IMPROVE TO MVFR AFT 00Z/04.
KCID/KMLI/KBRL SHOULD REMAIN VFR THROUGH 09Z/04 AND THEN SLOWLY
DETERIORATE TO MVFR CONDITIONS AFT 09Z/04. ANOTHER STORM SYSTEM
WILL IMPACT EASTERN IOWA AND NORTHERN ILLINOIS AFT 12Z/04.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...08
AREA FORECAST DISCUSSION
NWS GOODLAND KS
227 PM MST TUE FEB 3 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 227 PM MST TUE FEB 3 2015
VISIBLE AND IR IMAGERY INDICATED MOSTLY CLEAR SKIES ACROSS THE TRI
STATE AREA IN THE EARLY AFTERNOON. WATER VAPOR IMAGERY INDICATED
MOST OF THE AVAILABLE MOISTURE IN THE ATMOSPHERE TO THE NORTHWEST OF
THE FORECAST AREA AHEAD OF AN UPPER LEVEL SHORTWAVE TROUGH
POSITIONED IN CENTRAL CANADA. RAP ANALYSIS SHOWED A BROAD LOW
AMPLITUDE UPPER LEVEL TROUGH OVER THE EASTERN TWO THIRDS OF THE
CONUS WITH A LOW AMPLITUDE RIDGE OVER THE WESTERN THIRD OF THE
CONUS.
INCREASING AMOUNTS OF POTENTIAL VORTICITY AHEAD OF AVAILABLE UPPER
LEVEL MOISTURE WILL BRING INCREASED CLOUD COVER THIS EVENING AND
OVERNIGHT. AN UPPER LEVEL SHORTWAVE TROUGH WILL PUSH ACROSS THE
UPPER CENTRAL PLAINS OVERNIGHT TOWARDS THE EARLY MORNING HOURS
WEDNESDAY...WHICH WILL BRING CHANCES FOR LIGHT SNOW TO THE FORECAST
AREA TOMORROW. MODEL GUIDANCE RANGES BETWEEN 1 AND 2 INCHES FOR
SOUTHWEST NEBRASKA...BUT MOST MODEL FORECASTS ARE NOW BACKING OFF
AMOUNTS GREATER THAN 1 INCH. BECAUSE THE UPPER LEVEL SYSTEM WITH
MOST OF THE JET LIFT IS NOW DEPICTED IN GUIDANCE AS PASSING TO THE
NORTH AND EAST OF THE FORECAST AREA...CHANCES AND FORECAST
CONFIDENCE FOR RECEIVING GREATER THAN 1.5 INCHES OF SNOW IS
DIMINISHING. THERE IS STILL A CHANCE THAT THE WEATHER SYSTEM COULD
DIP FURTHER SOUTH THAN EXPECTED AS SHOWN IN PREVIOUS MODEL RUNS...SO
IT IS POSSIBLE FOR SOME LOCATIONS IN SOUTHWEST NEBRASKA TO STILL END
UP TO 2 INCHES.
LIGHT SNOW WILL CONTINUE THROUGH THE MORNING HOURS AND INTO THE
AFTERNOON. THE STORM SYSTEM WILL SLIDE TO THE EAST WITH A SURFACE
HIGH PRESSURE MOVING INTO THE AREA BY THE EARLY EVENING...WHICH WILL
END SNOWFALL FOR WEDNESDAY EVENING. WINDS COULD GUST UP TO 35 KTS AT
TIMES WITH A STRONGER 40KT LOW LEVEL JET MOVING THROUGH FOR
LOCATIONS EAST OF U.S. HIGHWAY 83...WHICH COULD BRING SOME MARGINAL
BLOWING SNOW FOR SOME LOCATIONS. STRONG COLD AIR ADVECTION UNDER
NORTHWEST FLOW ALOFT WILL BRING TEMPERATURES BETWEEN THE MID 20S TO
THE LOWER 30S FOR HIGHS WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 124 PM MST TUE FEB 3 2015
UPPER RIDGE WILL BUILD IN BEHIND THE DEPARTING SYSTEM BEGINNING
WEDNESDAY NIGHT AND DOMINATE THROUGH THE END OF THE WEEK. DRY
CONDITIONS AND MUCH WARMER TEMPERATURES WILL BE THE RESULT. RECORD
TO NEAR RECORD HIGH TEMPERATURES WILL BE POSSIBLE ON FRIDAY WITH
HIGHS IN THE MID TO UPPER 70S. EARLY NEXT WEEK LOOKS LIKE MORE OF
THE SAME...WITH WESTERN RIDGE REBUILDING OVER THE CENTRAL ROCKIES
ON MONDAY AND HIGH PLAINS ON TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1037 AM MST TUE FEB 3 2015
VFR CONDITIONS WILL CONTINUE FOR BOTH TERMINALS THROUGH THE REST
OF TODAY AND TONIGHT WITH LIGHT WIND SHIFTS. THE MAIN WEATHER TO
AFFECT THE TERMINALS WILL BE A WINTER SYSTEM THAT WILL MOVE
THROUGH CENTRAL NEBRASKA AND BRING SOME SNOW. LIGHT SNOW WILL
AFFECT KMCK FIRST DURING THE EARLY MORNING HOURS...WHICH WILL
BRING LOWERED VISIBILITIES AND CEILINGS. LIGHT SNOW WILL THEN
AFFECT KGLD TOWARD MID MORNING.
GUSTY WINDS BEHIND THE COLD FRONTAL PASSAGE WILL GUST UP TO 30
KTS...WHICH MAY BRING SOME PATCHY BLOWING SNOW AT TIMES.
CONFIDENCE WAS NOT HIGH ENOUGH TO MENTION BLOWING SNOW IN THE
TAFS...BUT IT COULD BE CONSIDERED FOR FUTURE TAFS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...MK
LONG TERM...024
AVIATION...MK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
240 PM CST TUE FEB 3 2015
...UPDATED SHORT TERM AND LONG TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 226 PM CST TUE FEB 3 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWED A ZONAL WEST-NORTHWEST FLOW
PATTERN ACROSS THE WESTERN HALF OF THE CONUS. HIGH LEVEL PACIFIC
MOISTURE WAS ADVANCING EASTWARD ON THE EQUATORWARD SIDE OF THE JET
FROM OFF THE PAC NORTHWEST COAST INTO THE NORTHERN ROCKIES. THE
CONTINUED DOWNSLOPE MOMENTUM LED TO PERSISTENT LEESIDE LOW PRESSURE
ACROSS THE CENTRAL PLAINS. BY MID-AFTERNOON, A SURFACE LOW WAS
CENTERED OVER NORTH CENTRAL NEBRASKA WITH A TROUGH AXIS EXTENDING
SOUTH-SOUTHWESTWARD INTO WESTERN KANSAS. ALONG AND WEST OF THE
TROUGH AXIS, SURFACE WINDS WERE FROM THE WEST OR NORTHWEST, WHICH IS
WHERE THE WARMEST TEMPERATURES WERE FOUND. THE ARCTIC AIRMASS WAS
FOUND NORTH OF THE LOW, WHICH WILL ADVANCE SOUTH TONIGHT ONCE AN
ARCTIC PERTURBATION IN THE MID/UPPER LEVEL FLOW WILL ROTATE
SOUTHEAST FROM THE SOUTHERN CANADIAN PRAIRIES INTO THE UPPER MIDWEST
(TONIGHT THROUGH EARLY WEDNESDAY). SURFACE ANTICYCLOGENESIS WILL BE
STRONG IN THE WAKE OF THIS FEATURE ACROSS THE NORTHERN HIGH PLAINS,
WITH A SHARP COLD FRONT BEING THE RESULT AS THE HIGH EXPANDS
SOUTHWARD.
THE TIMING OF THE FRONT STILL LOOKS ON TRACK FOR EARLY WEDNESDAY
MORNING. OVERNIGHT TEMPERATURES WILL FALL TO THE MID TO UPPER 20S,
WHICH WILL ACTUALLY BE THE WEDNESDAY HIGH TEMPERATURE FOR MOST
LOCATIONS. INTENSE COLD AIR ADVECTION, LOW CLOUD COVER, AND STRONG
NORTH WINDS WILL LEAD TO A VERY UNPLEASANT DAY. WE BOOSTED THE WIND
SPEEDS TO AROUND 23 TO 26 KNOTS SUSTAINED FOR ESPECIALLY THE MORNING
HOURS WITH THE ISALLOBARIC WIND AND PRESSURE GRADIENT BEING
STRONGEST THE FEW HOURS AFTER INITIAL FRONTAL PASSAGE. TEMPERATURES
WILL SLOWLY FALL THROUGH THE 20S AND EVENTUALLY UPPER TEENS,
PERHAPS, BY LATE AFTERNOON, ESPECIALLY ACROSS CENTRAL KANSAS. AS FAR
AS THE SNOW FORECAST IS CONCERNED, NOT MUCH WAS CHANGED ON THAT
FRONT. WE KEPT THE HIGHEST POPS OF AROUND 50 TO 60 PERCENT UP IN THE
FAR NORTHEAST (CENTRAL KANSAS) CLOSER TO WHERE MID LEVEL
FRONTOGENESIS WILL BE STRONGER, BUT EVEN THAT WILL BE WEAKENING
RAPIDLY THROUGH THE DAY AS THE 700MB FRONT AND MOISTURE BAND MOVE
SOUTH TOWARD OUR REGION. WE WILL KEEP A FEW TENTHS OF AN INCH OF
SNOW ACCUMULATION UP AROUND HAYS. THE WRF-NMM HAS THE HIGHEST
SNOWFALL OF AROUND AN INCH, BUT SINCE IT IS THE OUTLIER, MUCH LESS
WEIGHT WAS GIVEN TO THIS SOLUTION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 226 PM CST TUE FEB 3 2015
THE EXTENDED PERIOD WILL SEE A CONTINUATION OF A BROAD NORTHWEST
FLOW PATTERN ALOFT OVER THE CENTRAL CONUS. AT THE BEGINNING OF THE
PERIOD ON WEDNESDAY NIGHT, A SHORTWAVE TROUGH IN THE UPPER FLOW WILL
BE EXITING THE CENTRAL PART OF THE COUNTRY TOWARD THE EAST. IN THE
WAKE OF THIS SYSTEM, COLD CANADIAN HIGH PRESSURE WILL BE SITUATED
OVER THE CENTRAL PLAINS. THIS HIGH PRESSURE WILL MOVE TOWARD THE
CENTRAL MISSISSIPPI VALLEY THROUGH THE NIGHT WHILE LEE SIDE TROUGHING
REDEVELOPS OVER EASTERN COLORADO. WEDNESDAY NIGHT WILL START OUT
MAINLY CLOUDY BUT CLOUDS SHOULD BEGIN DECREASING OVERNIGHT.
TEMPERATURES WILL BE COLDEST OVER CENTRAL/SOUTH CENTRAL KANSAS WHERE
OVERNIGHT LOWS WILL LIKELY FALL INTO THE UPPER SINGLE DIGITS AND
LOWER TEENS. FARTHER WEST, TEMPERATURES SHOULD ONLY FALL INTO THE
MID/UPPER TEENS TO AROUND 20 WHERE THE IMPACTS OF THE HIGH PRESSURE
WILL BE LESSER AND SOUTHERLY FLOW WILL RETURN SOONER IN THE NIGHT.
LOW LEVEL WARM ADVECTION WILL CONTINUE ON THURSDAY WITH TEMPERATURES
CLIMBING BACK INTO THE THE LOW 40S IN CENTRAL KANSAS AND THE
MID/UPPER 50S ALONG THE COLORADO BORDER.
VERY MILD WEATHER WILL ROUND OUT THE REST OF THE EXTENDED PERIOD AS
A BUILDING UPPER LEVEL RIDGE AND LOW LEVEL DOWNSLOPE WARMING ALLOW
DAYTIME HIGH TEMPERATURES TO TOP OUT IN THE UPPER 60S AND 70S
THROUGH NEXT WEEKEND.
CHANCES FOR PRECIPITATION MAY INCREASE AGAIN TOWARD THE MIDDLE OF
NEXT WEEK. THE MEDIUM RANGE MODELS SHOW THE UPPER FLOW PATTERN
AMPLIFYING SOMEWHAT WITH THE POSSIBILITY OF A SHORTWAVE TROUGH
MOVING OUT INTO THE CENTRAL CONUS. THE 12Z GFS IS SHOWING AN
ANTICYCLONIC WAVE BREAK OCCURRING OVER THE DESERT SOUTHWEST. NUMEROUS
GFS ENSEMBLE MEMBERS ARE ALSO SHOWING THIS. THE CANADIAN MODEL IS
ALSO TRENDING IN THIS DIRECTION. THE 12Z ECMWF HOWEVER, IS SHOWING
THE WAVE DIGGING INTO THE CENTRAL PLAINS AND CLOSING OFF AS IT DOES.
OBVIOUSLY A LOT OF UNCERTAINTY AT THIS TIME AND MODEL SOLUTIONS WITH
THIS SYSTEM WILL BE SUBJECT TO CHANGE IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1033 AM CST TUE FEB 3 2015
AVIATION WEATHER WILL BE FAIRLY TRANQUIL THROUGH THE REMAINDER OF
THE DAY AS SOUTHWEST WINDS WILL AVERAGE 8 TO 12 KNOTS IN A LIGHT
LEE TROUGH PRESSURE GRADIENT. A STRONG COLD FRONT WILL BE MAKING
ITS WAY SOUTH OVERNIGHT, REACHING HAYS JUST PRIOR TO DAYBREAK
WEDNESDAY AND GARDEN CITY/DODGE CITY ABOUT AN HOUR TO HOUR AND A
HALF LATER. WINDS WILL INCREASE SHARPLY TO 20 TO 25 KNOTS
SUSTAINED WITH PERIODS OF GUSTS IN THE 35 TO 40 KNOT RANGE. LOW
STRATUS CLOUDS WILL ALSO ACCOMPANY THE FRONT WITH CEILING EXPECTED
TO FALL DOWN WELL INTO THE IFR RANGE AND PERHAPS SOME LIFR AT
TIMES JUST AFTER THE FRONTAL PASSAGE IN THE MORNING. WHILE SOME
VERY LIGHT SNOW OR FLURRIES WILL BE POSSIBLE AROUND THE HAYS AREA,
WE WILL LEAVE OUT OF THE TAF FOR NOW GIVEN THE EXPECTED LOW
IMPACT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 26 29 14 49 / 0 20 10 0
GCK 28 31 15 54 / 0 20 10 0
EHA 34 38 19 57 / 0 10 0 0
LBL 29 34 17 53 / 0 10 10 0
HYS 24 26 12 46 / 0 60 10 0
P28 30 32 12 39 / 0 20 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...GERARD
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
450 PM EST TUE FEB 3 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 449 PM EST TUE FEB 3 2015
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW WNW FLOW INTO THE UPPER
GREAT LAKES. THERE ARE A COUPLE OF SHORTWAVES NOTED UPSTREAM. THE
FIRST IS TRACKING INTO CNTRL/SRN MN...AND THE SECOND IS OVER CNTRL
MANITOBA. THE FORMER IS PRODUCING AN AREA OF -SN THAT IS MOVING
ACROSS CNTRL/SRN MN INTO WI. THE LATTER WILL HAVE AN IMPACT ON LES
LATER TONIGHT AND WED MORNING. AS FOR ONGOING LES...LES HAS BEEN
MOSTLY ON THE LIGHT SIDE AND DISORGANIZED TODAY. HOWEVER...SOME
DOMINANT BANDS HAVE BEEN EVIDENT ON RADAR AND VIS SATELLITE IMAGERY.
ONE IN PARTICULAR WAS AFFECTING THE HOUGHTON VCNTY EARLIER TODAY.
WITH LIGHT WINDS AND HIGH SNOW TO WATER RATIOS...IMPACTS HAVE
PROBABLY BEEN LIMITED. WITH DAYTIME WEAKENING OF LAND BREEZES AND
LOCALIZED COVERGENCE...THESE HEAVIER SNOW BANDS HAVE WEAKENED.
FIRST SHORTWAVE WILL MOVE ACROSS SRN WI INTO LWR MI TONIGHT. BASED
ON RADAR EXTRAPOLATION AND MODEL GUIDANCE...IT APPEARS THE NRN EDGE
OF THE ASSOCIATED SNOW MAY JUST CLIP SCNTRL UPPER MI THIS EVENING.
OTHERWISE...ATTENTION TURNS TO NEXT SHORTWAVE TROF THAT WILL REACH
NRN MN/ADJACENT NRN ONTARIO BY 12Z WED. MODELS SHOW DEEP LAYER
QVECTOR CONVERGENCE SPREADING OVER LAKE SUPERIOR OVERNIGHT AS
SHORTWAVE APPROACHES. IN RESPONSE...FCST SOUNDINGS SHOW INVERSION
LIFTING FROM 4KFT THIS EVENING TO UPWARDS OF 10KFT OR MORE BY 12Z
WED. IN NW UPPER MI...HIGH RES MODELS TEND TO FOCUS LOW-LEVEL
CONVERGENCE ROUGHLY BTWN ROCKLAND AND HOUGHTON. THIS IS A TYPICAL
LOCATION FOR CONVERGENCE TO FOCUS UNDER SYNOPTIC WNW FLOW DUE TO
STRENGTHENING LAND BREEZE COMPONENT TO WIND AT NIGHT...PARTICULARLY
WHEN WINDS ARE ON THE LIGHTER SIDE AS THEY WILL BE TONIGHT. GIVEN
THE RISING INVERSION/STRENGTHENING CONVERGENCE...LES ADVY IS
WARRANTED FOR ONTONAGON/NRN HOUGHTON COUNTIES. ALTHOUGH DEEP LAYER
QVECTOR CONVERGENCE DEPARTS IN THE MORNING...A FOLLOWING SHORTWAVE
BRINGS ANOTHER ROUND OF FORCING IN THE AFTN. THIS RESULTS IN ONLY A
SLOW FALL OF THE INVERSION TO AROUND 6KFT BY LATE AFTN. DGZ WILL
STILL OCCUPY AT LEAST SOME OF THE LOWER PORTION OF THE CONVECTIVE
LAYER TONIGHT BEFORE BECOMING CONFINED CLOSER TO THE SFC WED AFTN
UNDER CAA REGIME WHICH DROPS 850MB TEMPS TO -25 TO -27C BY EVENING.
SO...HIGHER SNOW TO WATER RATIOS UPWARDS OF 25 OR MORE TO 1 TONIGHT
WILL FALL TO UNDER 20 TO 1 WED. IN THE END...EXPECT SNOW
ACCUMULATIONS OF 4-8 INCHES BY WED EVENING WITH GREATEST AMOUNTS
BTWN ROCKLAND AND HOUGHTON. GIVEN THE INVERSION HEIGHTS...CERTAINLY
POSSIBLE MUCH GREATER SNOW ACCUMULATIONS COULD OCCUR IF THE
CONVERGENCE BECOMES STRONGLY FOCUSED. INCREASING NW WINDS
WED...GUSTING TO 20-30MPH... WILL LEAD TO BLSN AND SHARPLY REDUCED
VIS. MAY END UP NEEDING AN ADVY FOR KEWEENAW COUNTY DUE TO BLSN
ON WED.
TO THE E...FCST IS MUCH MORE CHALLENGING. LIGHTER WINDS TONIGHT
COMBINED WITH FAIRLY SOLID LOOKING ICE COVER FROM WHITEFISH BAY N TO
MICHIPICOTEN BAY SHOULD LEAD TO A HEALTHY LAND BREEZE PUSHING WELL
OUT INTO ERN LAKE SUPERIOR. END RESULT WILL BE A STRONG CONVERGENCE
ZONE DEVELOPING BTWN THIS WESTWARD PUSHING LAND BREEZE AND THE WNW
WINDS OVER CNTRL LAKE SUPERIOR. VERY HVY SNOW SHOULD EVENTUALLY
DEVELOP IN THE CONVERGENCE ZONE...BUT THERE IS LITTLE AGREEMENT ON
HOW THE SNOW BAND WILL EVOLVE...WHERE IT WILL BE LOCATED AND WHETHER
MUCH OF IT WILL IMPACT UPPER MI. STEADY WNW WINDS OF 25-30KT UP AT
850MB DO SUGGEST SOME OF THIS HVY SNOW SHOULD IMPACT PARTS OF ERN
ALGER/NRN LUCE COUNTIES...BUT UNCERTAINTY IS HIGH ENOUGH TO PRECLUDE
ANY HEADLINES ATTM. WILL BE SOMETHING TO CLOSELY MONITOR TONIGHT. ON
WED...STRENGTHENING WNW FLOW WILL OVERCOME THE LAND BREEZE AND PUSH
THE HEAVIER SNOW ONSHORE...FOLLOWED BY THE DEVELOPMENT OF WNW MULTI-
BAND LES. WILL LIKELY NEED AN ADVY FOR ALGER (MAINLY E HALF OF THE
COUNTY) AND LUCE WITH THE POTENTIAL FOR 3-6 INCHES OF SNOW WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 235 PM EST TUE FEB 3 2015
LAKE EFFECT SNOW WILL BE ONGOING IN THE NORTHWEST WIND SNOWBELTS
WEDNESDAY EVENING AND WILL LIKELY BE FALLING MODERATELY IN SOME
LOCATIONS WITH THE FAVORABLE INVERSION HEIGHTS (RISING TO 10KFT).
WILL CONTINUE TO SHOW DEFINITE POPS IN THE NORTHWEST WIND SNOW
BELTS FOR WEDNESDAY EVENING...BUT THEN QUICKLY DIMINISH FROM WEST
TO EAST AS A HIGH PRESSURE RIDGE (FROM A HIGH IN THE CENTRAL PLAINS)
MOVES ACROSS THE CWA. THIS RIDGE WILL LEAD TO THE SUBSIDENCE
INVERSION QUICKLY LOWERING AND WINDS BACKING...LEADING TO LESS
FAVORABLE CONDITIONS FOR LAKE EFFECT. BEFORE THAT OCCURS...COULD SEE
A COUPLE INCHES OF ADDITIONAL ACCUMULATIONS IN THE FAVORED NORTHWEST
WIND LOCATIONS DURING THE EVENING. OVER THE EAST...MODELS CONTINUE
TO SHOW THE LAND BREEZE OFF ONTARIO AND THE ICE ALONG THE EASTERN
SHORELINE OF LAKE SUPERIOR AIDING IN INCREASED CONVERGENCE AND THE
POTENTIAL FOR A MORE DOMINATE BAND DEVELOPING BETWEEN GRAND MARAIS
AND WHITEFISH POINT. CONFIDENCE IS STILL LOW ON PINNING DOWN THE
EXACT LOCATION...BUT WILL SHOW SOME HIGHER AMOUNTS (TOWARDS 3
INCHES) DURING THE EVENING TO ACCOUNT FOR THAT. THE MAIN LIMITING
FACTOR TO LARGER SNOWFALL AMOUNTS WILL BE THE CONVECTIVE CLOUD
LAYER LOCATED ABOVE THE DGZ AND PRODUCING SMALL FLAKES. WHILE THIS
WILL BE EFFECT AT REDUCING VISIBILITIES IN THE BAND...THE WEAKENING
WINDS WILL LIKELY LIMIT THE IMPACT OF THE BLOWING SNOW OUTSIDE OF
THE BAND. WITH THOSE BACKING WINDS AND LESS FAVORABLE CONDITIONS
FOR LAKE EFFECT...EXPECT CLEARING TO OCCUR OVER THE INTERIOR WEST
OVERNIGHT. THAT WILL PROVIDE GREAT RADIATIONAL COOLING UNDER WINDS
BECOMING NEARLY CALM AND WILL CONTINUE TO FOLLOW THE LOW END OF
GUIDANCE FOR LOWS IN THAT AREA (TEENS BELOW ZERO). WITH WINDS
BECOMING LIGHT...DON/T EXPECT THERE TO BE ENOUGH WIND TO SUPPORT
WIND CHILL HEADLINES BUT WILL CONTINUE TO MENTION IN HWO.
MUCH OF THURSDAY LOOKS TO BE QUIET AS THE HIGH PRESSURE RIDGE
DEPARTS THE AREA. THIS WILL SHIFT OFF ANY REMAINING LAKE EFFECT
NORTHEAST OVER LAKE SUPERIOR DURING THE MORNING HOURS. THAT QUIET
PERIOD OF WEATHER WILL BE SHORT LIVED...AS THE NEXT SHORTWAVE (AND
WEAK SURFACE TROUGH) DIVES SOUTHEAST ACROSS NORTHERN ONTARIO AND
NORTHERN LAKE SUPERIOR THURSDAY EVENING. WITH THE BEST
MOISTURE/FORCING OVER THE NORTHEAST HALF OF THE CWA...WILL SHOW LOW
CHANCES FOR SNOW IN THAT AREA...BUT AT LEAST MENTION A SLIGHT CHANCE
OF SNOW OVER MUCH OF THE REST OF THE CWA. THE QUICK DEPARTURE OF THE
WAVE WILL GIVE A VERY QUICK BREAK OVERNIGHT THURSDAY AND INTO FRIDAY
MORNING...BEFORE THE NEXT SHORTWAVE AND SURFACE TROUGH MOVE ACROSS
THE UPPER GREAT LAKES REGION ON FRIDAY AFTERNOON/NIGHT. STILL SOME
DIFFERENCES IN THE MODELS ON THE TRACK OF THE SHORTWAVE AND IN TURN
THE LOCATION OF THE BEST MID LEVEL WARM AIR ADVECTION...MOVING
ACROSS PART OF THE CWA. WILL CONTINUE TO SHOW HIGH CHANCE POPS FOR
FRIDAY AFTERNOON/NIGHT AS IT MOVES THROUGH THE AREA...ALTHOUGH MOST
LOCATIONS WILL ONLY SEE ACCUMULATIONS AROUND AN INCH. ON THE
BACKSIDE OF THE TROUGH...SHOULD SEE LOW LEVEL WINDS TURN TO THE
NORTH AND ALLOW FOR LAKE ENHANCEMENT (TRANSITIONING TO LAKE EFFECT
ON SATURDAY). MODELS ARE STILL VARYING ON THE INFLUENCE OF THE HIGH
PRESSURE RIDGE NOSING INTO THE AREA ON SATURDAY (FROM A HIGH IN
CENTRAL CANADA)...SO CONFIDENCE IS LOW ON THE AMOUNT OF LAKE EFFECT
COVERAGE HEADING INTO SATURDAY NIGHT. WITH THE HIGH KEEPING
INVERSION HEIGHTS BELOW 4-5KFT...DON/T EXPECT THE AMOUNTS TO BE TOO
MUCH BUT WILL STILL SHOW HIGH CHANCE AND LOW LIKELY VALUES FOR THE
FAVORED NORTHERLY WIND AREA (ESPECIALLY IN THE UPSLOPE LOCATIONS).
THE NEXT SHORTWAVE LOOKS TO STAY SOUTH OF THE AREA ON SATURDAY
NIGHT (MOVES THROUGH THE CENTRAL MISSISSIPPI VALLEY) WHILE THE
SURFACE HIGH SLIDES SOUTHEAST THROUGH NORTHERN ONTARIO. THE
SUBSIDENCE FROM THIS HIGH WILL LIMIT THE COVERAGE/INTENSITY OF ANY
LAKE EFFECT OCCURRING UNDER THE VEERING LOW LEVEL FLOW THROUGH
SUNDAY. THEN AS THE HIGH SHIFTS INTO QUEBEC AND THE SURFACE RIDGE
SLOWLY SLIDES EAST OF THE AREA THROUGH MONDAY...WOULD EXPECT THE
WINDS TO VEER ENOUGH TO THE SOUTH TO PUSH ANY LIGHT LAKE EFFECT
OFFSHORE. THERE ARE SOME HINTS OF A WEAK DISTURBANCE AFFECTING THE
AREA MONDAY NIGHT AND TUESDAY...BUT WILL JUST HAVE SILENT POPS FOR
THAT PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1247 PM EST TUE FEB 3 2015
AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE FCST PERIOD UNDER
W TO NW WINDS ACROSS LAKE SUPERIOR. DOMINANT SNOW BAND THAT RECENTLY
RESULTED IN LIFR CONDITIONS AT KCMX SHOULD WEAKEN AND SHIFT A LITTLE
THIS AFTN. SO...EXPECTATION IS FOR IFR CONDITIONS TO IMPROVE TO MVFR
THIS AFTN/EVENING. HOWEVER...AS IS TYPICAL FOR LAKE EFFECT SNOW...
CONDITIONS COULD BE HIGHLY VARIABLE AT TIMES. APPROACHING
DISTURBANCE WILL INCREASE LAKE EFFECT SNOW LATE TONIGHT/WED
MORNING...RESULTING IN A RETURN OF PREVAILING IFR CONDITIONS.
INCREASING WINDS WED MORNING WILL ALSO FURTHER REDUCE VIS DUE TO
BLSN.
AT KIWD/KSAW...VFR CONDITIONS SHOULD PREVAIL THRU THE AFTN UNDER A W
WIND WITH TRAJECTORIES ACROSS LAND. AS WINDS VEER A BIT TONIGHT/WED
MORNING TO RESULT IN AT LEAST SOME OVERLAKE WIND TRAJECTORIES...
EXPECT -SHSN TO DEVELOP...ESPECIALLY AT KIWD WHERE CONDITIONS WILL
LIKELY FALL TO IFR. MVFR CONDITIONS WILL DEVELOP AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 449 PM EST TUE FEB 3 2015
A COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR LATE TONIGHT AND WED
MORNING. NW WINDS OF 20-30 KNOTS ARE EXPECTED BEHIND THE FRONT ON
WED WITH THE POTENTIAL FOR GALE FORCE GUSTS OVER ERN LAKE SUPERIOR.
HEAVY FREEZING SPRAY IS ALSO EXPECTED...ESPECIALLY FOR THE EAST HALF
OF LAKE SUPERIOR. WINDS WILL DIMINISH WED NIGHT AND THEN BACK SW AND
STRENGTHEN ON THU AHEAD OF ANOTHER TROUGH THAT PASSES LATE THU NIGHT
AND FRI. THE SW WINDS MAY GUST TO GALE FORCE AT TIMES THU
AFTN/EVENING. WINDS WILL DIMINISH FRI AND THEN STRENGTHEN TO 15-25KT
OUT OF THE N FOR SAT. WINDS WILL STAY MOSTLY IN THE 15-25KT RANGE
INTO SUN AS THEY VEER EASTERLY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 7 PM EST
WEDNESDAY FOR MIZ002-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 9 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
235 PM EST TUE FEB 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST TUE FEB 3 2015
CONCERNS FOCUS ON LES AND ADVISORY HEADLINES OVER THE KEWEENAW
PENINSULA THIS MORNING.
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING ACROSS NRN ONTARIO AND EXITING LAKE
SUPERIOR TO THE NE. AT THE SFC...A TROUGH EXTENDS ACROSS THE SRN
PORTION OF LAKE SUPERIOR AND THE KEWEENAW PENINSULA THIS MORNING.
THIS TROUGH ALONG WITH ENHANCED CONVERGENCE FROM LAND BREEZES OFF
UPPER MI HAS FOCUSED A DOMINANT LES BAND ACROSS THE SRN PORTION OF
LAKE SUPERIOR INTERSECTING THE KEWEENAW PENINSULA BTWN HOUGHTON AND
CALUMET. VISIBILITY BRIEFLY DROPPED TO 1/4 MILE AT KCMX AS THIS BAND
MOVED ACROSS THE AREA SHORTLY AFT MIDNIGHT.
TODAY... WITH THE ONTARIO SHORTWAVE DEPARTING NE OF LAKE SUPERIOR WE
ALREADY MAY BE SEEING SIGNS OF DOMINANT LES BAND WEAKENING OVER SRN
LAKE SUPERIOR AND THE SRN PORTION OF THE KEWEENAW PENINSULA. IT
APPEARS THAT CLOUD TOPS ARE WARMING WHERE THE LES BAND IS LOCATED AS
NOTED ON IR SATELLITE IMAGERY AND REFLECTIVITY RETURNS MAY ALSO BE
WEAKENING SOME WITHIN THE PAST HR. LOOKING AT MODEL FCST SOUNDINGS
WOULD EXPECT WEAKENING TREND TO CONTINUE WITH THIS DOMINANT LES BAND
THROUGH THE MORNING HRS AS INVERSION BASES LOWER FM 5KFT TO 3KFT...
DRYING OCCURS BLO THE INVERSION...AND LOW-LVL CONVERGENCE WEAKENS.
280-290 FLOW LES WILL CONTINUE ACROSS SRN LAKE SUPERIOR INTO NW AND
FAR NE UPPER MI WITH 850 MB TEMPS REMAINING -19/-20C. BUT LOWERING
INVERSION HEIGHTS...DRYING BLO INVERSION AND WEAKENING CONVERGENCE
WILL LIMIT POTENTIAL FOR ADDITIONAL ACCUMULATIONS TO 1 TO 3 INCHES
NW AND 1-2 INCHES ALONG ERN SHORELINE EAST OF MUNISING. HAVE
MAINTAINED LES ADVISORY FOR KEWEENAW-NRN HOUGHTON COUNTIES THROUGH
12Z BUT DO NOT ANTICIPATE HAVING TO EXTEND ADVISORY.
TONIGHT...A WEAK SHORTWAVE MOVING THROUGH THE NRN PLAINS TODAY WILL
SLIDE JUST SOUTH OF THE CWA...ALTHOUGH THERE COULD BE A LIGHT SNOW
SHOWER BRUSHING SOUTHERN MENOMINEE COUNTY THIS EVENING.
MEANWHILE...LIGHT LAKE EFFECT SNOW WILL BE ONGOING IN THE WEST-
NORTHWEST WIND SNOW BELTS OF NORTHERN LAKE SUPERIOR. WHILE AMOUNTS
WON/T BE ANYTHING TOO SIGNIFICANT INITIALLY THIS EVENING...A
STRONGER SHORTWAVE FROM SCNTRL CANADA WILL DROP SOUTHEAST ACROSS THE
AREA LATE TONIGHT AND WEDNESDAY...BRINGING COLDER 8H TEMPS TO THE
AREA UNDER NORTHWEST WINDS. 8H TEMPS WILL FALL TO -21C OVER EASTERN
LAKE SUPERIOR AND -24C WEST WHICH WILL HELP STEEPEN MID LEVEL LAPSE
RATES AND ALLOW THE INVERSION HEIGHTS TO RISE FROM 4KFT TO AROUND
7KFT BY 12Z WED ESPECIALLY OVER THE WESTERN CWA. THUS...WOULD EXPECT
THE INTENSITY OF THE SNOW SHOWERS TO INCREASE LATE TONIGHT ESPECIALLY
OVER THE WRN CWA AS THE INVERSION HEIGHTS RISE AND MOISTURE DEEPENS
WITH ENHANCEMENT FROM THE SHORTWAVE. DAY SHIFT WILL LIKELY NEED TO
CONSIDER LES ADVISORIES FOR THE NW WIND SNOWBELTS LATE TONIGHT INTO
WEDNESDAY. BLOWING SNOW MAY BECOME MORE OF AN ISSUE ON WEDNESDAY AS
NORTHWEST WINDS WITHIN THE CONVECTIVE LAYER INCREASE IN EXCESS OF 20
KTS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 235 PM EST TUE FEB 3 2015
LAKE EFFECT SNOW WILL BE ONGOING IN THE NORTHWEST WIND SNOWBELTS
WEDNESDAY EVENING AND WILL LIKELY BE FALLING MODERATELY IN SOME
LOCATIONS WITH THE FAVORABLE INVERSION HEIGHTS (RISING TO 10KFT).
WILL CONTINUE TO SHOW DEFINITE POPS IN THE NORTHWEST WIND SNOW
BELTS FOR WEDNESDAY EVENING...BUT THEN QUICKLY DIMINISH FROM WEST
TO EAST AS A HIGH PRESSURE RIDGE (FROM A HIGH IN THE CENTRAL PLAINS)
MOVES ACROSS THE CWA. THIS RIDGE WILL LEAD TO THE SUBSIDENCE
INVERSION QUICKLY LOWERING AND WINDS BACKING...LEADING TO LESS
FAVORABLE CONDITIONS FOR LAKE EFFECT. BEFORE THAT OCCURS...COULD SEE
A COUPLE INCHES OF ADDITIONAL ACCUMULATIONS IN THE FAVORED NORTHWEST
WIND LOCATIONS DURING THE EVENING. OVER THE EAST...MODELS CONTINUE
TO SHOW THE LAND BREEZE OFF ONTARIO AND THE ICE ALONG THE EASTERN
SHORELINE OF LAKE SUPERIOR AIDING IN INCREASED CONVERGENCE AND THE
POTENTIAL FOR A MORE DOMINATE BAND DEVELOPING BETWEEN GRAND MARAIS
AND WHITEFISH POINT. CONFIDENCE IS STILL LOW ON PINNING DOWN THE
EXACT LOCATION...BUT WILL SHOW SOME HIGHER AMOUNTS (TOWARDS 3
INCHES) DURING THE EVENING TO ACCOUNT FOR THAT. THE MAIN LIMITING
FACTOR TO LARGER SNOWFALL AMOUNTS WILL BE THE CONVECTIVE CLOUD
LAYER LOCATED ABOVE THE DGZ AND PRODUCING SMALL FLAKES. WHILE THIS
WILL BE EFFECT AT REDUCING VISIBILITIES IN THE BAND...THE WEAKENING
WINDS WILL LIKELY LIMIT THE IMPACT OF THE BLOWING SNOW OUTSIDE OF
THE BAND. WITH THOSE BACKING WINDS AND LESS FAVORABLE CONDITIONS
FOR LAKE EFFECT...EXPECT CLEARING TO OCCUR OVER THE INTERIOR WEST
OVERNIGHT. THAT WILL PROVIDE GREAT RADIATIONAL COOLING UNDER WINDS
BECOMING NEARLY CALM AND WILL CONTINUE TO FOLLOW THE LOW END OF
GUIDANCE FOR LOWS IN THAT AREA (TEENS BELOW ZERO). WITH WINDS
BECOMING LIGHT...DON/T EXPECT THERE TO BE ENOUGH WIND TO SUPPORT
WIND CHILL HEADLINES BUT WILL CONTINUE TO MENTION IN HWO.
MUCH OF THURSDAY LOOKS TO BE QUIET AS THE HIGH PRESSURE RIDGE
DEPARTS THE AREA. THIS WILL SHIFT OFF ANY REMAINING LAKE EFFECT
NORTHEAST OVER LAKE SUPERIOR DURING THE MORNING HOURS. THAT QUIET
PERIOD OF WEATHER WILL BE SHORT LIVED...AS THE NEXT SHORTWAVE (AND
WEAK SURFACE TROUGH) DIVES SOUTHEAST ACROSS NORTHERN ONTARIO AND
NORTHERN LAKE SUPERIOR THURSDAY EVENING. WITH THE BEST
MOISTURE/FORCING OVER THE NORTHEAST HALF OF THE CWA...WILL SHOW LOW
CHANCES FOR SNOW IN THAT AREA...BUT AT LEAST MENTION A SLIGHT CHANCE
OF SNOW OVER MUCH OF THE REST OF THE CWA. THE QUICK DEPARTURE OF THE
WAVE WILL GIVE A VERY QUICK BREAK OVERNIGHT THURSDAY AND INTO FRIDAY
MORNING...BEFORE THE NEXT SHORTWAVE AND SURFACE TROUGH MOVE ACROSS
THE UPPER GREAT LAKES REGION ON FRIDAY AFTERNOON/NIGHT. STILL SOME
DIFFERENCES IN THE MODELS ON THE TRACK OF THE SHORTWAVE AND IN TURN
THE LOCATION OF THE BEST MID LEVEL WARM AIR ADVECTION...MOVING
ACROSS PART OF THE CWA. WILL CONTINUE TO SHOW HIGH CHANCE POPS FOR
FRIDAY AFTERNOON/NIGHT AS IT MOVES THROUGH THE AREA...ALTHOUGH MOST
LOCATIONS WILL ONLY SEE ACCUMULATIONS AROUND AN INCH. ON THE
BACKSIDE OF THE TROUGH...SHOULD SEE LOW LEVEL WINDS TURN TO THE
NORTH AND ALLOW FOR LAKE ENHANCEMENT (TRANSITIONING TO LAKE EFFECT
ON SATURDAY). MODELS ARE STILL VARYING ON THE INFLUENCE OF THE HIGH
PRESSURE RIDGE NOSING INTO THE AREA ON SATURDAY (FROM A HIGH IN
CENTRAL CANADA)...SO CONFIDENCE IS LOW ON THE AMOUNT OF LAKE EFFECT
COVERAGE HEADING INTO SATURDAY NIGHT. WITH THE HIGH KEEPING
INVERSION HEIGHTS BELOW 4-5KFT...DON/T EXPECT THE AMOUNTS TO BE TOO
MUCH BUT WILL STILL SHOW HIGH CHANCE AND LOW LIKELY VALUES FOR THE
FAVORED NORTHERLY WIND AREA (ESPECIALLY IN THE UPSLOPE LOCATIONS).
THE NEXT SHORTWAVE LOOKS TO STAY SOUTH OF THE AREA ON SATURDAY
NIGHT (MOVES THROUGH THE CENTRAL MISSISSIPPI VALLEY) WHILE THE
SURFACE HIGH SLIDES SOUTHEAST THROUGH NORTHERN ONTARIO. THE
SUBSIDENCE FROM THIS HIGH WILL LIMIT THE COVERAGE/INTENSITY OF ANY
LAKE EFFECT OCCURRING UNDER THE VEERING LOW LEVEL FLOW THROUGH
SUNDAY. THEN AS THE HIGH SHIFTS INTO QUEBEC AND THE SURFACE RIDGE
SLOWLY SLIDES EAST OF THE AREA THROUGH MONDAY...WOULD EXPECT THE
WINDS TO VEER ENOUGH TO THE SOUTH TO PUSH ANY LIGHT LAKE EFFECT
OFFSHORE. THERE ARE SOME HINTS OF A WEAK DISTURBANCE AFFECTING THE
AREA MONDAY NIGHT AND TUESDAY...BUT WILL JUST HAVE SILENT POPS FOR
THAT PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1247 PM EST TUE FEB 3 2015
AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE FCST PERIOD UNDER
W TO NW WINDS ACROSS LAKE SUPERIOR. DOMINANT SNOW BAND THAT RECENTLY
RESULTED IN LIFR CONDITIONS AT KCMX SHOULD WEAKEN AND SHIFT A LITTLE
THIS AFTN. SO...EXPECTATION IS FOR IFR CONDITIONS TO IMPROVE TO MVFR
THIS AFTN/EVENING. HOWEVER...AS IS TYPICAL FOR LAKE EFFECT SNOW...
CONDITIONS COULD BE HIGHLY VARIABLE AT TIMES. APPROACHING
DISTURBANCE WILL INCREASE LAKE EFFECT SNOW LATE TONIGHT/WED
MORNING...RESULTING IN A RETURN OF PREVAILING IFR CONDITIONS.
INCREASING WINDS WED MORNING WILL ALSO FURTHER REDUCE VIS DUE TO
BLSN.
AT KIWD/KSAW...VFR CONDITIONS SHOULD PREVAIL THRU THE AFTN UNDER A W
WIND WITH TRAJECTORIES ACROSS LAND. AS WINDS VEER A BIT TONIGHT/WED
MORNING TO RESULT IN AT LEAST SOME OVERLAKE WIND TRAJECTORIES...
EXPECT -SHSN TO DEVELOP...ESPECIALLY AT KIWD WHERE CONDITIONS WILL
LIKELY FALL TO IFR. MVFR CONDITIONS WILL DEVELOP AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST TUE FEB 3 2015
A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR TONIGHT INTO
EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO NEAR GALES ARE
POSSIBLE WED...STRONGEST OVER THE EAST HALF. HEAVY FREEZING SPRAY IS
EXPECTED DURING THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE
SUPERIOR. WINDS WILL BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH
THAT CROSSES LATE FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE
TROUGH INTO THE WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1247 PM EST TUE FEB 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST TUE FEB 3 2015
CONCERNS FOCUS ON LES AND ADVISORY HEADLINES OVER THE KEWEENAW
PENINSULA THIS MORNING.
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE WRN CONUS AND A BROAD TROUGH FROM NRN HUDSON BAY INTO THE ERN
CONUS RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. A WEAK
SHORTWAVE TROUGH WAS MOVING ACROSS NRN ONTARIO AND EXITING LAKE
SUPERIOR TO THE NE. AT THE SFC...A TROUGH EXTENDS ACROSS THE SRN
PORTION OF LAKE SUPERIOR AND THE KEWEENAW PENINSULA THIS MORNING.
THIS TROUGH ALONG WITH ENHANCED CONVERGENCE FROM LAND BREEZES OFF
UPPER MI HAS FOCUSED A DOMINANT LES BAND ACROSS THE SRN PORTION OF
LAKE SUPERIOR INTERSECTING THE KEWEENAW PENINSULA BTWN HOUGHTON AND
CALUMET. VISIBILITY BRIEFLY DROPPED TO 1/4 MILE AT KCMX AS THIS BAND
MOVED ACROSS THE AREA SHORTLY AFT MIDNIGHT.
TODAY... WITH THE ONTARIO SHORTWAVE DEPARTING NE OF LAKE SUPERIOR WE
ALREADY MAY BE SEEING SIGNS OF DOMINANT LES BAND WEAKENING OVER SRN
LAKE SUPERIOR AND THE SRN PORTION OF THE KEWEENAW PENINSULA. IT
APPEARS THAT CLOUD TOPS ARE WARMING WHERE THE LES BAND IS LOCATED AS
NOTED ON IR SATELLITE IMAGERY AND REFLECTIVITY RETURNS MAY ALSO BE
WEAKENING SOME WITHIN THE PAST HR. LOOKING AT MODEL FCST SOUNDINGS
WOULD EXPECT WEAKENING TREND TO CONTINUE WITH THIS DOMINANT LES BAND
THROUGH THE MORNING HRS AS INVERSION BASES LOWER FM 5KFT TO 3KFT...
DRYING OCCURS BLO THE INVERSION...AND LOW-LVL CONVERGENCE WEAKENS.
280-290 FLOW LES WILL CONTINUE ACROSS SRN LAKE SUPERIOR INTO NW AND
FAR NE UPPER MI WITH 850 MB TEMPS REMAINING -19/-20C. BUT LOWERING
INVERSION HEIGHTS...DRYING BLO INVERSION AND WEAKENING CONVERGENCE
WILL LIMIT POTENTIAL FOR ADDITIONAL ACCUMULATIONS TO 1 TO 3 INCHES
NW AND 1-2 INCHES ALONG ERN SHORELINE EAST OF MUNISING. HAVE
MAINTAINED LES ADVISORY FOR KEWEENAW-NRN HOUGHTON COUNTIES THROUGH
12Z BUT DO NOT ANTICIPATE HAVING TO EXTEND ADVISORY.
TONIGHT...A WEAK SHORTWAVE MOVING THROUGH THE NRN PLAINS TODAY WILL
SLIDE JUST SOUTH OF THE CWA...ALTHOUGH THERE COULD BE A LIGHT SNOW
SHOWER BRUSHING SOUTHERN MENOMINEE COUNTY THIS EVENING.
MEANWHILE...LIGHT LAKE EFFECT SNOW WILL BE ONGOING IN THE WEST-
NORTHWEST WIND SNOW BELTS OF NORTHERN LAKE SUPERIOR. WHILE AMOUNTS
WON/T BE ANYTHING TOO SIGNIFICANT INITIALLY THIS EVENING...A
STRONGER SHORTWAVE FROM SCNTRL CANADA WILL DROP SOUTHEAST ACROSS THE
AREA LATE TONIGHT AND WEDNESDAY...BRINGING COLDER 8H TEMPS TO THE
AREA UNDER NORTHWEST WINDS. 8H TEMPS WILL FALL TO -21C OVER EASTERN
LAKE SUPERIOR AND -24C WEST WHICH WILL HELP STEEPEN MID LEVEL LAPSE
RATES AND ALLOW THE INVERSION HEIGHTS TO RISE FROM 4KFT TO AROUND
7KFT BY 12Z WED ESPECIALLY OVER THE WESTERN CWA. THUS...WOULD EXPECT
THE INTENSITY OF THE SNOW SHOWERS TO INCREASE LATE TONIGHT ESPECIALLY
OVER THE WRN CWA AS THE INVERSION HEIGHTS RISE AND MOISTURE DEEPENS
WITH ENHANCEMENT FROM THE SHORTWAVE. DAY SHIFT WILL LIKELY NEED TO
CONSIDER LES ADVISORIES FOR THE NW WIND SNOWBELTS LATE TONIGHT INTO
WEDNESDAY. BLOWING SNOW MAY BECOME MORE OF AN ISSUE ON WEDNESDAY AS
NORTHWEST WINDS WITHIN THE CONVECTIVE LAYER INCREASE IN EXCESS OF 20
KTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM EST TUE FEB 3 2015
AT 12Z WED...A SFC COLD FRONT WILL BE OVER THE SERN CWA AHEAD OF A
SHORTWAVE AND MUCH COLDER AIR MOVING INTO THE AREA. NW WIND LES WILL
BE ONGOING AT THE START OF THE PERIOD AND WILL INTENSIFY THROUGH WED
EVENING. 850MB TEMPS WILL BE -20C TO -25C AT 12Z WED BUT WILL
DECREASE TO -25C TO -30C BETWEEN 18Z WED AND 06Z THU. LOW LEVEL
WINDS WILL BE NEARLY UNIDIRECTIONAL INTO EARLY WED
NIGHT...SUPPORTING MULTI BAND LES STRUCTURE. ONE EXCEPTION IS OVER
ERN UPPER MI...BETWEEN GRAND MARAIS AND WHITEFISH POINT...WHERE THE
LAND BREEZE OFF ONTARIO AND ICE COVERAGE ALONG THE ONTARIO SHORE MAY
LEAD TO A STRONGER MORE DOMINANT BAND. LAKE INDUCED EQUILIBRIUM
LEVELS WILL INCREASE TO AROUND 11KFT WED AFTERNOON AND
EVENING...MEANING HEAVY LES. WITH THE COLD TEMPS...THE CONVECTIVE
LAYER WILL BE OUT OF THE DGZ...SO DENDRITE SIZE WILL BE SMALL AND
SNOW TO LIQUID RATIOS BELOW 20 TO 1. WHILE THIS WILL BE A LIMITATION
FOR SNOWFALL AMOUNTS...THE SMALL FLAKES WILL BE EFFICIENT AT
REDUCING . THEREFORE...THE GREATLY LOWERED VISIBILITIES ARE
ANTICIPATED TO BE THE DOMINANT HAZARD DURING THE EVENT. THE LES WILL
DIMINISH FROM W TO E WED NIGHT BEFORE MOVING OFFSHORE THU MORNING AS
A SFC RIDGE MOVES W TO E THROUGH THE AREA. MIN TEMPS WED NIGHT WILL
RANGE FROM 0F ALONG THE SHORELINES TO
-15F
OVER THE INTERIOR W. WILL CONTINUE TO MENTION THESE COLDER TEMPS IN
THE HWO...BUT LIGHT WINDS WILL LIKELY NOT MEET CRITERIA FOR WIND
CHILL ADVISORIES.
A CLIPPER SHORTWAVE LOOKS TO MOVE NE OF THE CWA THU EVENING INTO THU
NIGHT...BUT MOST OF THE PRECIP ASSOCIATED WITH THE SYSTEM LOOKS TO
STAY NE OF THE CWA. SOME LAKE ENHANCED SNOW COULD RESULT ACROSS THE
NRN KEWEENAW PENINSULA AND MAYBE FAR NERN UPPER MI WITH LIGHT
AMOUNTS IF ANYTHING.
QUITE OF BIT OF UNCERTAINTY WITH SMALLER SCALE DETAILS OF A SERIES
OF SHORTWAVE SAT THROUGH MON. TOO EARLY TO SAY IF SYNOPTIC PRECIP
WILL RESULT IN THE CWA. MODELS DO SHOW N-NE WINDS LATE FRI NIGHT
THROUGH AT LEAST SAT /GFS VEERS WINDS TO A SLY DIRECTION WHILE THE
ECMWF KEEPS NE WINDS INTO MON/. THE GFS SHOWS 850MB TEMPS AROUND
-15C...WHICH WOULD FAVOR HIGHER SNOW TO LIQUID RATIOS AND GREATER
SNOWFALL AMOUNTS DURING THE FAVORABLE FLOW. THE ECMWF SHOWS 850MB
TEMPS OF -20C TO -25C...WHICH WOULD FAVOR LOWER RATIOS BUT STRONGER
LES OVERALL AND ALSO LONGER DURATION OF LES INTO MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1247 PM EST TUE FEB 3 2015
AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE FCST PERIOD UNDER
W TO NW WINDS ACROSS LAKE SUPERIOR. DOMINANT SNOW BAND THAT RECENTLY
RESULTED IN LIFR CONDITIONS AT KCMX SHOULD WEAKEN AND SHIFT A LITTLE
THIS AFTN. SO...EXPECTATION IS FOR IFR CONDITIONS TO IMPROVE TO MVFR
THIS AFTN/EVENING. HOWEVER...AS IS TYPICAL FOR LAKE EFFECT SNOW...
CONDITIONS COULD BE HIGHLY VARIABLE AT TIMES. APPROACHING
DISTURBANCE WILL INCREASE LAKE EFFECT SNOW LATE TONIGHT/WED
MORNING...RESULTING IN A RETURN OF PREVAILING IFR CONDITIONS.
INCREASING WINDS WED MORNING WILL ALSO FURTHER REDUCE VIS DUE TO
BLSN.
AT KIWD/KSAW...VFR CONDITIONS SHOULD PREVAIL THRU THE AFTN UNDER A W
WIND WITH TRAJECTORIES ACROSS LAND. AS WINDS VEER A BIT TONIGHT/WED
MORNING TO RESULT IN AT LEAST SOME OVERLAKE WIND TRAJECTORIES...
EXPECT -SHSN TO DEVELOP...ESPECIALLY AT KIWD WHERE CONDITIONS WILL
LIKELY FALL TO IFR. MVFR CONDITIONS WILL DEVELOP AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST TUE FEB 3 2015
A STRONG COLD FRONT WILL MOVE ACROSS LAKE SUPERIOR TONIGHT INTO
EARLY WEDNESDAY MORNING. NW WINDS OF 30 KNOTS TO NEAR GALES ARE
POSSIBLE WED...STRONGEST OVER THE EAST HALF. HEAVY FREEZING SPRAY IS
EXPECTED DURING THIS TIME...ESPECIALLY FOR EAST HALF OF LAKE
SUPERIOR. WINDS WILL BACK SW ON THURSDAY AHEAD OF ANOTHER TROUGH
THAT CROSSES LATE FRIDAY...AND THEN WILL BECOME NORTHERLY BEHIND THE
TROUGH INTO THE WEEKEND. WINDS SHOULD STAY AT OR BELOW 30 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
105 PM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 105 PM CST TUE FEB 3 2015
LATEST ADDITION TO FLURRIES FOR THE HWY 200 CORRIDOR AND
NORTH...ENDING AROUND 19Z...SEEMS TO BE WORKING OUT AS FLURRIES
HAVE ENDED HERE AT FGF OFFICE. WITH POPS IN DECENT SHAPE FOR
REMAINDER OF AFTN...FOCUS TURNS TO OVERNIGHT LOWS AND WIND CHILL
HEADLINES. MODEL GUIDANCE COMING IN WARMER THAN INHERITED GRIDS
AND HAVE ONLY BLENDED NEW SUPER BLEND WITH PREV FCST LOW...WHICH
STILL YIELDS VALUES COLDER THAN GUIDANCE. RIGHT NOW IT LOOKS LIKE
THE APPARENT TEMPS WILL NOT FALL INTO ADVISORY CRITERIA UNTIL
AROUND OR AFTER 12Z (SECOND PERIOD) AND DO NOT FORESEE ISSUANCE OF
HEADLINES THIS SHIFT...BUT DECISION HAS NOT BEEN MADE PENDING MORE
COORDINATION WITH BIS OFFICE. ADVISORY WILL BE ISSUED WITH 4 PM
CST FCST IF APPROPRIATE.
UPDATE ISSUED AT 925 PM CST TUE FEB 3 2015
MORNING UPDATE WILL FOCUS ON ONGOING LIGHT SNOW OVER SOUTHEASTERN
NORTH DAKOTA. LATEST MODELED RUC GUIDANCE INCREASES SLIGHTLY THE
QPF OVER SOUTHEASTERN ND AND THE MODELED RAP SNOW RATIOS ARE
SLIGHTLY HIGHER...WHICH MAKES SENSE GIVEN A SLIGHT INCREASE IN
REFLECTIVITIES OVER THE REGION...DUE TO PROXIMITY OF MID LEVEL
FRONTOGENETIC FORCING. HAVE POPULATED QPF AND SNOW RATIO WITH THIS
GUIDANCE AND RERUN SNOW AMOUNTS...WHICH BUMPS SNOWFALLS UP TO THE
ONE AND A HALF TO TWO INCH RANGE. ALSO ADJUSTED POPS TO BRING
LIKELIES INTO VALLEY CITY AND PUSHED SOUTHWARD THE NO SNOW
GRADIENT WITHIN THE VALLEY...AS FAR HAS NOT SEEN ANY PRECIP THE
LAST TWO OBS. NO OTHER CHANGES MADE ON THIS UPDATE.
UPDATE ISSUED AT 630 AM CST TUE FEB 3 2015
THE LIGHT SNOW BAND IS SHIFTING SLOWLY SOUTH WHEN LOOKING AT RADAR
TRENDS AND THE LATEST MESOSCALE MODELS. WE WILL KEEP POPS PRETTY
MUCH THE SAME...BUT LOWER SNOW TOTALS FOR THE FAR SOUTHERN
VALLEY...WITH MOST AREAS LESS THAN AN INCH. THERE COULD BE AN
INCH...PERHAPS 2 IN FAR SOUTHWEST SARGENT COUNTY. OTHERWISE...MOST
AREAS SHOULD BE DRY TODAY WITH A FLURRY PERHAPS AND PLENTY OF CLOUDS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 255 AM CST TUE FEB 3 2015
THE MAIN CHALLENGE WILL BE SNOW BAND TODAY THAT WILL AFFECT
SOUTHEAST ND INTO ADJACENT PORTIONS OF WC MN. THE GLOBAL MODELS AT
00Z WERE IN GOOD AGREEMENT...ALTHOUGH SOME OF THE LATEST MESOSCALE
MODELS...ESPECIALLY THE HOPWRF ARE SHIFTING THE MAIN SNOW BAND
JUST SOUTH OF THE REGION. THEREFORE...WE WILL HAVE TO MONITOR
WHERE THIS SNOW BAND DEVELOPS THIS MORNING.
FOR TODAY...THE AFOREMENTIONED LIGHT SNOW BAND THAT SHOULD PRODUCE
A BAND OF 1-2 INCHES SHOULD AFFECT THE FAR SOUTHERN FA TODAY.
THERE IS A 6HR WINDOW OF LIFT PER ISENTROPIC/QG FIELDS THAT WILL
QUICKLY MOVE THROUGH IN THE 15-21Z TIME FRAME. THERE IS QUITE A BIT
OF DRY AIR IN PLACE INITIALLY...SO SOME LIFT WILL GO TO SATURATE
COLUMN. WINDS SHOULD BE ON THE LIGHT SIDE WITH THIS SYSTEM...AND WE
WILL MONITOR THIS SNOW THREAT TODAY AND UPDATE AS NEEDED.
TONIGHT...A COLD FRONT WILL MOVE FROM NORTH TO SOUTH AND DANGEROUS
WIND CHILLS MAY DEVELOP AT LEAST IN THE NORTH. SKIES SHOULD CLEAR
OUT WITH THE COLD AIR MOVING IN.
ON WED...IT WILL BE A COLD DAY WITH 490 DECAMETER THICKNESS VALUES IN THE
NORTH. TEMPS WILL STRUGGLE TO REACH 0 IN THE NORTH AND SINGLE
DIGITS ABOVE IN THE SOUTH. WIND CHILLS COULD BE IN ADVISORY
CRITERIA FROM 25-30 BELOW DURING THE MORNING HOURS IN THE NORTH AT LEAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 AM CST TUE FEB 3 2015
FOR WED NIGHT AND THU...EXPECT A DRY PERIOD WITH MID LEVEL TEMPS
WARMING. TEMPS COULD BE STEADY LATER WED NIGHT AND PERHAPS RISE A
BIT IN THE WEST. TEMPS SHOULD RISE ABOVE NORMAL ON THU AHEAD OF
THE NEXT SYSTEM.
FOR THU NIGHT...A CLIPPER TYPE SYSTEM MAY SPREAD SOME LIGHT SNOW
IN THE NORTH WITH STRONG MID LEVEL WAA. THIS COULD BE THE START TO
A BIT MORE ACTIVE PATTERN WITH A STRONG BAROCLINIC ZONE OVER THE REGION.
FRIDAY-MONDAY...A FEW OPPORTUNITIES FOR PRECIP ARE EXPECTED THROUGH
THE WEEKEND. A STRONG LOW-LEVEL THERMAL GRADIENT WILL OSCILLATE
ACROSS THE NORTHERN PLAINS AS SHORTWAVE TROUGHS RIPPLE THROUGH THE
RATHER ZONAL UPPER FLOW. THE TIMING AND LOCATION OF THESE SYSTEMS
WILL IMPACT TEMP TRENDS...AND HAVE STUCK WITH A MODEL BLEND FOR NOW
GIVEN THE LOW DEGREE OF CONFIDENCE WITH SUCH DETAILS. THE SYSTEMS
THAT WILL IMPACT THE REGION WILL HAVE MORE OF A PACIFIC ORIGIN...AND
MORE MOISTURE TO WORK WITH THAN MOST OF THE SYSTEMS RECENTLY. THE
00Z GFS INDICATES PW VALUES NEAR 0.5 INCHES OVER THE AREA ON FRIDAY
AS ONE SYSTEM MOVES THROUGH. RIGHT NOW THE 00Z GFS/ECMWF INDICATE A
BAND OF LIGHT SNOW ASSOCIATED WITH MID-LEVEL FRONTOGENESIS PRIMARILY
AFFECTING NE ND/NW MN...WITH ANOTHER SYSTEM FOR SATURDAY. PLENTY OF
UNCERTAINTY REMAINS WITH THE TRACK AND TIMING OF SYSTEMS IN THIS
TYPE OF PATTERN...THOUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 105 PM CST TUE FEB 3 2015
IFR CONDITIONS WERE OVER THE SOUTHERN RED RIVER VALLEY FROM FALLING
SNOW. VFR CONDITIONS WERE OVER THE NORTHERN VALLEY AND MVFR
CONDITIONS BETWEEN. EXPECT IFR/MVFR CONDITIONS TO SHIFT EAST
SOUTHEAST THE REST OF THE AFTERNOON. SOME MID LEVEL CLOUDS WERE OVER
FAR SOUTHERN SASK AND WILL ALSO DRIFT SOUTHEAST INTO THE AREA THIS
AFTERNOON AND TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1155 AM CST TUE FEB 3 2015
.UPDATE...
ISSUED AT 1151 AM CST TUE FEB 3 2015
SNOW CONTINUES SOUTH CENTRAL AND IS ENDING WEST. WILL CONTINUE
THIS TREND THROUGH THE AFTERNOON. SO FAR GETTING 1 TO 2 INCH
SNOWFALL AMOUNTS ACROSS THE REGION.
UPDATE ISSUED AT 851 AM CST TUE FEB 3 2015
AREA OF SNOW CURRENTLY MOVING THROUGH WESTERN AND CENTRAL NORTH
DAKOTA. THE SNOW IS BEGINNING TO TAPER OFF SOUTHWEST AND WILL BE
DIMINISHING RAPIDLY THIS AFTERNOON. MADE SOME ADJUSTMENTS TO THE
POPS TO ACCOUNT FOR THE TRENDS. LATEST HRRR HAS NEARLY ALL THE SNOW
ENDING BY MID AFTERNOON.
UPDATE ISSUED AT 612 AM CST TUE FEB 3 2015
SNOW CONTINUES OVER THE AREA WITH THE PRIMARY BAND ORIENTATED FROM
WEST CENTRAL INTO SOUTH CENTRAL NORTH DAKOTA. PREVIOUS FORECAST
REFLECTED THIS QUITE WELL...ONLY CHANGE WAS TO INCREASE POPS SOME
ALONG THIS BAND. SNOW IS STILL EXPECTED TO TAPER BY AFTERNOON AS
SURFACE LOW NOW PUSHING INTO FAR NORTHWEST SOUTH DAKOTA CONTINUES
ITS SOUTHEASTERLY TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST TUE FEB 3 2015
THE MAIN FOCUS FOR THE SHORT TERM IS LIGHT SNOW ACCUMULATIONS
BETWEEN 1 AND 3 INCHES (ISOLATED HIGHER AMOUNTS POSSIBLE).
LIGHT SNOW CONTINUES TO OVERSPREAD WESTERN AND CENTRAL NORTH
DAKOTA THIS MORNING AHEAD OF A SURFACE LOW IN EASTERN MONTANA.
RADAR AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE WEST
CENTRAL AND SOUTHERN NORTH DAKOTA WILL SEE THE HEAVIEST AMOUNTS OF
SNOW THIS MORNING AND AFTERNOON. THE 06 NAM AND GFS CONTINUE TO
SHOW WIDESPREAD 2 TO 3 INCHES OF SNOW FROM WATFORD CITY DOWN
THROUGH BISMARCK AND ELLENDALE. SOME ISOLATED LOCATIONS COULD SEE
CLOSER TO 4 INCHES OF SNOW IN SOME OF THE HEAVIER SNOW BANDS.
THE MOST INTENSE AND ORGANIZED SNOW IS EXPECTED TO FALL DURING THE
MORNING HOURS. SNOW WILL COME TO AN END FROM WEST TO EAST BY THE
LATE MORNING AND EARLY AFTERNOON HOURS AS THE LOW PRESSURE CENTER
EXITS TO THE SOUTHEAST. TEMPERATURES TODAY WILL STRUGGLE TO CLIMB
MUCH WITH CLOUDY SKIES EXPECTED ALL DAY. WITH CLEARING SKIES AND
FRESH SNOWPACK TEMPERATURES WILL ONCE AGAIN DROP BELOW ZERO
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CST TUE FEB 3 2015
ACTIVE WEST/NORTHWEST FLOW WILL CONTINUE INTO THE EXTENDED PERIOD
WITH A VARIETY OF DISTURBANCES PUSHING THROUGH.
QUIET WEATHER IS EXPECTED TO START THE PERIOD ON WEDNESDAY INTO
EARLY THURSDAY WITH WEAK RIDGING OVER THE REGION. CHANGES COME FOR
THE END OF THE WEEK AS A PARADE OF MODEST SHORT WAVES START TO MOVE
THROUGH THE AREA AS A BAROCLINIC ZONE SETS UP OVER THE
NORTH...POSSIBLY SAGGING SOUTH BY THE WEEKEND THOUGH MODELS ARE
HAVING SOME TROUBLE WITH THE POSITION OF THIS. THIS WILL BRING
CHANCES FOR PRECIPITATION MAINLY NORTH THROUGH FRIDAY...SPREADING
SOUTHERLY INTO SATURDAY. THE MAIN QUESTION WILL BE PRECIPITATION
TYPES AS MODELS ADVERTISE WARMER TEMPS ALOFT PUSHING MORE OR LESS
INTO THE SOUTHWESTERN HALF OF THE STATE. WITH THIS...HAVE GONE WITH
MENTION OF FREEZING RAIN OVER PARTS OF THE AREA WHERE SURFACE TEMPS
REMAIN SUB FREEZING INTO SATURDAY. BEYOND THAT CONFIDENCE IN MODELS
DETERIORATES AS EC COOLS AND GFS REMAINS WARM SO WILL HOLD OFF OF
FREEZING RAIN MENTION FOR NOW TO SEE HOW MODELS TREND.
PRECIP CHANCES THEN REMAIN OVER VARIOUS PARTS OF THE AREA THROUGH
THE REMAINDER OF THE EXTENDED AS REGION REMAINS IN ACTIVE PATTERN.
SEASONABLY MILD TEMPS EXPECTED SOUTHWEST...CLOSER TO AVERAGE NORTH
CENTRAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1151 AM CST TUE FEB 3 2015
SURFACE LOW ACROSS WESTERN SOUTH DAKOTA WILL MOVE SOUTHEAST TODAY.
HIGH PRESSURE ACROSS SOUTHERN CANADA WILL MOVE INTO THE REGION
WEDNESDAY. SNOW WILL GRADUALLY END ACROSS SOUTH CENTRAL NORTH
DAKOTA THIS AFTERNOON. CONDITIONS WILL IMPROVE TO MVFR OR LOW VFR
BY EVENING. CLEARING ON WEDNESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AJ
LONG TERM...JJS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 PM CST TUE FEB 3 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 255 PM CST TUE FEB 3 2015
HIGHLIGHTS/CONCERNS:
1. DIMINISHING SNOW THIS EVENING
2. SNOW...OR NOT...SOUTH OF I-90 ON WEDNESDAY
3. BLOWING SNOW ADVISORY NEED FOR WEDNESDAY AFTERNOON?
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF NORTH AMERICA...DEEP
TROUGHING ACROSS THE EASTERN TWO THIRDS OF CANADA WITH A POTENT
SHORTWAVE DROPPING DOWN THROUGH CENTRAL SASKATCHEWAN AND
MANITOBA...AND A SHORTWAVE RIDING THROUGH WEST-NORTHWEST FLOW OVER
SOUTHWEST MN. THIS LATTER SHORTWAVE COMBINED WITH MID LEVEL
FRONTOGENESIS AND PRECIPITABLE WATER OF 0.3 TO 0.4 INCHES HAS
RESULTED IN A BAND OF SNOW IMPACTING OUR AREA. THIS BAND EXTENDS
FROM SOUTHEAST MINNESOTA THROUGH FAR NORTHEAST IOWA AND INTO
SOUTHWEST WISCONSIN. VISIBILITIES HAVE BEEN AS LOW AS 1/4 MILE IN
THIS BAND. AIRMASS ACROSS THE REGION REMAINS COLD WITH READINGS
MAINLY IN THE TEENS...DUE TO THE COLD START...FRESH SNOWPACK...
CLOUDS...FALLING SNOW AND 925MB TEMPS IN THE -8 TO -14C RANGE.
SURFACE MAP SHOWED A WARM FRONTAL BOUNDARY ALONG I-80 IN NEBRASKA
AND IOWA WITH A WEAK TROUGH CROSSING THE REGION. AN ARCTIC HIGH CAN
BE SEEN OVER ALBERTA DROPPING SOUTH WHERE TEMPERATURES ARE IN THE 0
TO 5 ABOVE RANGE.
VERY GOOD MODEL AGREEMENT EXISTS THAT AS THE SHORTWAVE OVER EASTERN
SOUTH DAKOTA MOVES INTO THE FORECAST AREA THIS EVENING...THE SNOW
WILL QUICKLY TAPER OFF WEST TO EAST. THIS HAS BEEN HANDLED WELL WITH
PREVIOUS FORECASTS SO LITTLE CHANGE IS REQUIRED. MAY BE ABLE TO DROP
SOME OF THE ADVISORIES EARLY. HOWEVER...PLENTY OF LOW LEVEL MOISTURE
LOOKS TO PERSIST IN THE WAKE OF TODAYS SNOW. AT THE SAME
TIME...COLDER 925MB AIR IS PROGGED TO ADVECT IN TO PLACE THAT
MOISTURE/CLOUD DECK INTO THE DENDRITIC GROWTH ZONE. WEAK OMEGA IS
PROGGED IN THIS CLOUD DECK FOR MUCH OF THE NIGHT...SO HAVE CARRIED
FLURRIES IN THE FORECAST ONCE THE ACCUMULATING SNOW ENDS. IN
FACT...THERE ARE SOME HINTS THAT THERE COULD EVEN BE A LITTLE
ACCUMULATION NORTH OF WISCONSIN HIGHWAY 29 IN THE 03.12Z GFS/NAM SO
CONTINUED TO CARRY A 20 PERCENT CHANCE OF ACTUAL ACCUMULATING SNOW
THERE. THE CLOUDS WILL HELP TO KEEP TEMPERATURES UP SOMEWHAT...BUT
THE ADVECTION OF COLDER 925MB AIR SHOULD STILL BRING READINGS DOWN
INTO THE LOWER SINGLE DIGITS.
ATTENTION THEN TURNS TO A MID LEVEL FRONTOGENESIS ZONE AND SNOW
PROGGED TO DEVELOP ACROSS NEBRASKA AFTER MIDNIGHT. THIS ZONE OCCURS
BETWEEN THE ARCTIC HIGH DROPPING INTO EASTERN MONTANA AND THE
CURRENT WARM FRONT PUSHING SOUTH OF I-70. 03.12Z GFS/NAM CONTINUE TO
PUSH THIS ZONE AND SNOW SOUTH OF THE FORECAST AREA AS THE ARCTIC
HIGH DROPS DOWN INTO NEBRASKA. 03.12Z CANADIAN/ECMWF HAVE SHIFTED
SLIGHTLY SOUTH TO NOW DRY OUT NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. GIVEN THIS TREND IN THE CANADIAN/ECMWF...HAVE REMOVED THE
LOW PRECIPITATION CHANCES.
ALTHOUGH WE MAY NOT PICK UP SNOW...EXPECT FALLING LATE AFTERNOON
TEMPERATURES AND BRISK NORTHERLY WINDS AS THE POTENT SHORTWAVE
TROUGH OVER SASKATCHEWAN/MANITOBA DROPS SOUTH. 925MB TEMPS FALL FROM
-12 TO -14C AT 12Z TO -14 TO -18C BY 00Z. THE NORTH WINDS WHICH
COULD GUST TO 25 MPH WILL PRODUCE SOME BLOWING AND DRIFTING SNOW AS
WELL. WILL NEED TO MONITOR POTENTIAL FOR AN ADVISORY ALONG/WEST OF
U.S. HIGHWAY 52...ESPECIALLY IF THE WINDS COME IN ANY STRONGER.
RIGHT NOW HAVE HIGHLIGHTED THE BLOWING SNOW IN THE HWO.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM CST TUE FEB 3 2015
LONG TERM HIGHLIGHTS/CONCERNS...
1. CHILLY WEDNESDAY NIGHT...LOWS AND WIND CHILLS
2. LIGHT SNOW ACCUMULATION ALONG/NORTH OF I-90 ON FRIDAY
3. MORE ACCUMULATING SNOW FOR ALL OF THE REGION THIS WEEKEND
COLD ADVECTION FROM WEDNESDAY AFTERNOON CONTINUES INTO WEDNESDAY
NIGHT. BY 12Z THURSDAY...925MB TEMPS ARE PROGGED BETWEEN -16 AND
-20C...WHILE THE ARCTIC HIGH PRESSURE RIDGE MOVES OVERHEAD. WINDS
DECOUPLING OVERNIGHT SHOULD ALLOW TEMPERATURES TO TANK BELOW
ZERO...WITH SOME OF THE TYPICAL WISCONSIN COLD SPOTS GETTING DOWN TO
20 BELOW. WINDS DECOUPLING SHOULD LIMIT WIND CHILL ADVISORY
NEED...EXCEPT FOR MAYBE WEST OF HIGHWAY 52 WHERE RETURN FLOW SETS UP
LATE TO GIVE SOME BREEZE.
QUIET WEATHER IS FORECAST FOR THURSDAY AND MUCH OF FRIDAY AS
SOUTHWESTERLY FLOW BRINGS IN WARMER AIR. COULD SEE HIGHS REACH TO OR
JUST SLIGHTLY ABOVE NORMAL ON FRIDAY. ALSO ON FRIDAY...A WARM FRONT
BOUNDARY LOOKS TO SET UP ALONG I-90. A SHORTWAVE COMING THROUGH
NORTHWEST FLOW ALOFT MAY ALLOW FOR SOME LIGHT SNOW ACCUMULATIONS
NORTH OF THIS FRONT...MAINLY ALONG AND NORTH OF I-94. THIS FEATURE
HAS BEEN CONSISTENTLY SHOWN...WITH SOME TREND TO DROP IT FARTHER
SOUTHWEST. CERTAINLY SOMETHING TO WATCH AND REQUIRING A MENTION OF
20-40 PERCENT CHANCES ALONG/NORTH OF I-90...HIGHEST NORTH OF I-94.
THE WEEKEND IS PROVING MORE INTERESTING. A SERIES OF SHORTWAVE
TROUGHS ARE PROGGED TO MOVE THROUGH...POSSIBLY ONE POTENT ONE
THROUGH IOWA SATURDAY NIGHT. ADDITIONALLY...ALL MODELS SHOW A
FRONTOGENESIS ZONE SETTING UP FROM MINNESOTA THROUGH WISCONSIN AND
POSSIBLY NORTHEAST IOWA AS WELL. AT A MINIMUM IT APPEARS AN ADVISORY
WILL BE NEEDED...BUT LOCATION IS STILL WELL UP IN THE AIR.
COLDER...DRIER AIR LOOKS TO FOLLOW IN THE WAKE OF THE ACCUMULATING
SNOW FOR MONDAY...RESULTING FROM DEEPER TROUGHING FORMING OVER THE
EASTERN U.S.. SLIGHTLY WARMER AIR MOVES IN FOR TUESDAY WITH A BRIEF
UPPER RIDGE COMING THROUGH...ALONG WITH A LOW CHANCE FOR SNOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1134 AM CST TUE FEB 3 2015
WATCHING A BAND OF SNOW MOVING IN ACROSS SOUTHERN MN/NORTHERN IA.
LOOK FOR THIS BAND OF ACCUMULATING SNOW TO OVERSPREAD THE AREA
FROM WEST TO EAST WITH KRST GETTING INTO SOME MODERATE SNOW/LIFR
CONDITIONS THROUGH THIS AFTERNOON. KLSE IS EXPECTED TO DROP INTO
IFR RANGE...BEING A BIT MORE NORTH OF THE EXPECTED HEAVIEST SNOW. LOOK
FOR THIS SNOW TO LET UP BY EARLY THIS EVENING WITH SOME LINGERING
FLURRIES THROUGH MOST OF THE NIGHT. TOTAL SNOWFALL FROM THIS
AFTERNOON INTO EARLY THIS EVENING LOOKS TO BE AROUND 3 INCHES FOR
KRST AND AROUND 2.5 INCHES FOR KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR
WIZ032>034-041>044-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS