Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/07/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
305 PM MST TUE FEB 5 2013
.SHORT TERM...NORTHWEST FLOW ALOFT ACROSS REGION AT THIS
TIME...GRADUALLY BECOMING A BIT MORE WESTERLY ACCORDING TO THE
PLATTEVILLE PROFILER. WINDS ALOFT NOT ALL THAT STRONG...WITH CROSS
MOUNTAIN FLOW AROUND 20 KTS AT MOUNTAIN TOP. A FEW GUSTS TOPPING
30-35 MPH ACROSS THE RIDGES AND HIGHER FOOTHILLS. ACROSS PLAINS
WEAK MESOCYCLONE IN THE DENVER AREA KEEPING SOUTHEAST WINDS ACROSS
MUCH OF THE AREA. SOME INCREASE IN HIGH LEVEL MOISTURE WITH A BIT
OF A WAVE CLOUD ALONG FOOTHILLS. FLOW ALOFT TO BECOME WESTERLY
TONIGHT AS UPPER TROUGH MOVES INTO THE NORTHERN GREAT BASIN.
WINDS ALOFT INCREASE SLIGHTLY...WITH LATEST RAP SHOWING CROSS
MOUNTAIN FLOW INCREASING TO 30 KTS. SHOULD SEE SOME INCREASE IN
WINDS ACROSS THE MOUNTAINS AND ALONG FOOTHILLS. MOISTURE TO
CONTINUE TO INCREASE WITH LATEST WRF SYNTHETIC SATELLITE IMAGERY
INDICATING WAVE CLOUD TO BECOME MORE PRONOUNCED ALONG FOOTHILLS
AND ADJACENT PLAINS OVERNIGHT. THIS INCREASE IN CLOUD SHOULD KEEP
MINS FAIRLY MILD IN AND NEAR FOOTHILLS. ON WEDNESDAY...UPPER
TROUGH EXPECTED TO PUSH ACROSS THE GREAT BASIN DURING THE MORNING
AND OVER WESTERN COLORADO AND WESTERN WYOMING BY THE EVENING.
MODEL CROSS SECTIONS CONTINUE TO INDICATE A GRADUAL DEEPENING OF
THE MOISTURE ACROSS THE MOUNTAINS THROUGH THE DAY. QG VERTICAL
VELOCITY PROGS SHOW SOME INCREASE IN MID LEVEL QG ASCENT. THERE
IS SOME INDICATION OF WEAK COLD AIR ADVECTION WITH LAPSE RATES
AND OROGRAPHICS GRADUALLY IMPROVING DURING THE AFTERNOON. SHOULD
BE ENOUGH FOR SOME CHANCE OF SNOW SHOWERS OVER THE MOUNTAINS BY
THE AFTERNOON. ANY ACCUMULATIONS WILL BE LIGHT AND CONFINED TO
WEST FACING SLOPES. ACROSS PLAINS...MODELS STILL HINTING AT WEAK
SURGE DURING THE AFTERNOON. GFS CONTINUES TO BE THE DEEPEST AND
STRONGEST WITH THIS SURGE...ALONG WITH CONSIDERABLE MORE MOISTURE.
LATEST CANADIAN ALSO INDICATING SOME CHANCE FOR PRECIPITATION
SPREADING ONTO THE ADJACENT PLAINS. AT THIS TIME IT APPEARS THAT
LOW LEVELS TO REMAIN FAIRLY DRY...WHICH SHOULD LIMIT PRECIP
CHANCES ALONG THE URBAN CORRIDOR. BETTER CHANCE FOR VIRGA WITH THE
DRIER LOW LEVELS WITH THE POTENTIAL FOR A FEW RAIN AND OR SNOW
SHOWERS ACROSS THE PALMER DIVIDE LATER IN THE AFTERNOON.
TEMPERATURES TO BE A FEW DEGREES COOLER DUE TO THE INCREASED
CLOUD COVER. GUIDANCE TEMPERATURES SEEM A FEW DEGREES TOO WARM.
.LONG TERM...MODELS ARE STILL SHOWING AN UPPER TROUGH AXIS MOVING
EASTWARD ACROSS THE CWA WEDNESDAY EVENING. THE FLOW BEHIND THE
UPPER TROUGH IS ZONAL AND PRETTY WEAK. THIS CONTINUES THURSDAY
INTO THURSDAY EVENING WITH A WEAK UPPER RIDGE MOVING OVER THE
FORECAST AREA. THE FLOW ALOFT BECOMES WEST-SOUTHWESTERLY AND
INCREASES THURSDAY NIGHT AND FRIDAY. ON FRIDAY NIGHT...THERE IS A
SOUTHWESTERLY JET MAXIMUM OVER THE CWA. THE QG VERTICAL VELOCITY
FIELDS HAVE WEAK DOWNWARD ENERGY PROGGED FOR THE CWA WEDNESDAY
NIGHT THROUGH THURSDAY EVENING. AFTER THAT...UPWARD MOTION IS
PROGGED TO MOVE INTO COLORADO. IT IS PRETTY WEAK FRIDAY INTO EARLY
EVENING...THEN INCREASES A BIT AND CONTINUES WELL INTO THE
EXTENDED PERIOD. THE BOUNDARY LAYER FLOW IS PROGGED TO BE UPSLOPE
FOR THE PLAINS AND FOOTHILLS WEDNESDAY EVENING. LATER WEDNESDAY
NIGHT...CONTINUING INTO FRIDAY MORNING...NORMAL DUIRNAL WIND
PATTERNS ARE LIKELY. ON FRIDAY...INTO THE EVENING...SOUTHWESTERLY
DOWNSLOPING WINDS DOMINATE. SOMETIME BETWEEN 06Z AND 12Z FRIDAY
OVERNIGHT/SATURDAY MORNING...A COLD FRONT WITH UPSLOPE BEHIND IT
IS TO MOVE INTO THE CWA. FOR MOISTURE...THE GFS HAS A DECENT
AMOUNT OVER THE FOOTHILLS AND PLAINS WEDNESDAY EVENING. THE NAM IS
WAY DRIER...AND THE ECMWF HAS SOME BUT ONLY IN THE MID AN UPPER
LEVELS. LATER WEDNESDAY NIGHT INTO EARLY THURSDAY EVENING IT IS
PRETTY DRY. MOISTURE BEGINS TO GRADUALLY INCREASE LATER THURSDAY
NIGHT TROUGH FRIDAY NIGHT...MAINLY OVER THE MOUNTAINS. THE QPF
FIELDS NOW SHOW MORE MEASURABLE PRECIPITATION OVER THE CWA THEN
THEY INDICATED ON YESTERDAY`S 12Z RUNS. IN THE FACT...THE GFS
SHOWS A FAIRLY DECENT AMOUNT OF SNOW OVER THE SOUTHWESTERN AND
SOUTH CENTRAL CWA...INCLUDING THE PALMER RIDGE UP INTO THE
WESTERN URBAN CORRIDOR. THE ECMWF SHOWS LESS...WITH NOTHING ON
NAM. THERE IS ALSO A TAD OF MEASURABLE PRECIPITATION OVER THE
MOUNTAINS FRIDAY NIGHT. FOR POPS WEDNESDAY EVENING...WILL GO WITH
20-50% IN APPROPRIATE AREAS. CONSIDERING LAST WEEK`S STORM WILL
COMPLETELY DISCOUNT THE NAM. IT`S PERFORMANCE WAS MISERABLE. NO
POPS THE THE REST OF WEDNESDAY NIGHT THROUGH FRIDAY. WILL BRING
MINOR POPS IN FRIDAY NIGHT WITH THE NEXT STORM. FOR
TEMPERATURES...THURSDAY`S HIGHS ARE 0-2 C COLDER THAN
WEDNESDAY`S. FRIDAY`S HIGHS ARE 1-3 C WARMER THAN THURSDAY`S. FOR
THE LATER DAYS...SATURDAY THROUGH TUESDAY...MODELS CONTINUE TO
INDICATE A DECENT UPPER TROUGH/CLOSED LOW TO AFFECT THE CWA FRIDAY
NIGHT INTO MONDAY. THE GFS AND ECMWF BOTH SHOW A CLOSED
CIRCULATION NEAR THE FOUR CORNERS ON SATURDAY. THE ECMWF HAS IT
OVER NORTHWESTERN KANSAS BY EARLY SUNDAY MORNING...THE GFS KEEPS
AROUND THE FOUR CORNERS THROUGH 12Z SUNDAY MORNING. BY 00Z SUNDAY
AFTERNOON LATE...THE GFS HAS IT OVER SOUTHWESTERN KANSAS...THE
ECMWF HAS IT OVER NORTH DAKOTA AND MINNESOTA. THEY BOTH STILL
KEEP AN UPPER TROUGH OVER COLORADO ALL THAT TIME CONTINUING THROUGH
MONDAY NIGHT. THE CANADIAN LOOKS MORE LIKE THE ECMWF CONCERNING
THE CIRCULATION CENTER(S)...BUT IT ALSO KEEPS AN UPPER TROUGH OVER
THE CWA THROUGH MONDAY. CERTAIN PARAMETERS BETWEEN THE MODELS ARE
STILL NOT IN SYNC BUT THERE IS A DECENT PROLONGED PERIOD OF
UPSLOPE FOR AREAS EAST OF THE DIVIDE...THERE IS DEEP MOISTURE...
THERE IS FAILRY COLD AIR AND THERE IS SYNOPTIC SCALE ENERGY.
CONFIDENCE OF SNOWFALL IS INCREASING.
&&
.AVIATION...SOUTHEAST WINDS ACROSS THE DENVER AREA BEGINNING TO
SHOW SIGNS OF BECOMING MORE SOUTHERLY AS WEAK MESOCYCLONE OVER
NORTH DENVER WEAKENS AND MOVES NORTHWARD. LATEST RAP AND HRRR
STILL SHOWING MORE OF A SOUTHEAST COMPONENT AT THE AREA AIRPORTS
FOR THE NEXT FEW HOURS...AND THIS STILL SEEMS REASONABLE. WINDS TO
THEN BECOME MORE SOUTH SOUTHWEST DURING THE EVENING AS DRAINAGE
FLOW BEGINS TO DOMINATE. SPEEDS SHOULD REMAIN AROUND 8 KTS OR
LESS. MID AND HIGH LEVEL MOISTURE TO GRADUALLY INCREASE OVERNIGHT
WITH WAVE CLOUD ALONG INCREASING IN COVERAGE BY THE MORNING.
CEILINGS SHOULD REMAIN ABOVE 12000 FEET. ON WEDNESDAY...WINDS TO
BECOME MORE SOUTHWEST AND INCREASE TO 10 KTS BY 15Z...SHIFING TO
THE NORTHWEST BY 19Z. WINDS TO BECOME MORE NORTHERLY AROUND 21Z AS
WEAK SURGE MOVES ACROSS THE REGION. MID LEVEL CLOUDS TO GRADUALLY
LOWER DURING THE DAY WITH 9000 FEET AGL CEILING BY 21Z. SLIGHT
CHANCE OF CEILINGS AROUND 6000 FEET AGL DEVELOPING LATE IN THE
DAY...WILL CONTINUE TO KEEP A SCATTERED CEILING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS ALBANY NY
510 PM EST TUE FEB 5 2013
.SYNOPSIS...
A CLIPPER SYSTEM WILL APPROACH AND MOVE ACROSS THE REGION
TONIGHT...BRINGING SOME VERY LIGHT SNOW TO THE AREA. FAIR WEATHER
IS EXPECTED MID WEEK AS HIGH PRESSURE BUILDS IN. A WIDESPREAD
SNOWFALL IS ANTICIPATED FOR THE LATER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 505 PM...RADAR AND SURFACE OBSERVATIONS ARE INDICATING SOME
LIGHT SNOW SHOWERS DEVELOPING ACROSS THE MID HUDSON
VALLEY...SOUTHEAST CATSKILLS AND NW CT. IT APPEARS TO BE A
SEEDER-FEEDER AS THE HIGH AND MID CLOUDS ARE SEEDING THE LOWER
CLOUDS ALREADY IN PLACE. SO WE WILL RAISE THOSE SOUTHERN THREE
COUNTIES TO LIKELY POPS FOR THE REMAINDER OF TONIGHT.
OTHERWISE...UPSTREAM RADARS CONTINUE TO SHOW A BAND OF PRECIP ACROSS
SOUTHERN LOWER MICHIGAN AND TRACKING SOUTHEAST TOWARD OHIO. LATEST
HRRR REFLECTIVITY CONTINUES TO FAVOR MORE SCATTERED ACTIVITY
EVOLVING TONIGHT SO WE WILL KEEP THE CURRENT POPS IN PLACE AT THIS
TIME.
PREV DISC...
PER THE H2O VAPOR LOOP ANALYSIS...A FAST MOVING SHORT WAVE WAS
CROSSING THE LOWER GREAT LAKES REGION THIS AFTERNOON. REGIONAL
RADARS SHOW A SCT-BKN LINE OF PRECIPITATION THAT WAS ASSOCIATED
WITH WEAK FORCING. THIS FORCING IS EXPECTED TO REMAIN QUASI-
FOCUSED AS IT MIGRATES ACROSS THE CWFA. EXPERIENTIAL FORECAST
REFLECTIVITIES LEAD BY THE HRRR ALL SUGGEST A SCATTERED NATURE TO
THE SNOWFALL TONIGHT. ALONG WITH THE MOS GUIDANCE...WE WILL DROP
BACK POPS TO THE HIGH CHC-SCT CATEGORY WITH ACCUMULATIONS LESS
THAN 1 INCH FOR MOST LOCATIONS. THE CLOUD COVER WILL LIKELY REMAIN
EXTENSIVE OVERNIGHT WHICH SHOULD KEEP TEMPS A LITTLE MILDER THAN
THIS MORNINGS VALUES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY...
MINOR LAKE EFFECT SNOW EVENT WILL BE POSSIBLE FOR PORTIONS OF THE
MOHAWK VALLEY AND ADIRONDACKS IN THE MORNING BEFORE THOSE
INVERSION HEIGHTS COLLAPSE TOWARD NOON. OTHERWISE...VARIABLE CLOUD
COVER WILL BEGIN TO SLOWLY IMPROVE THROUGH THE DAY AS TEMPERATURES
CLIMB INTO THE LOW-MID 30S FOR VALLEY LOCATIONS AND 20S ELSEWHERE.
WINDS WILL BE RATHER GUSTY THROUGH THE DAY AS WE MIX UP TO 30KT
MAGNITUDES. FURTHERMORE...THOSE WINDS MAY GET FUNNELED DOWN THE
MOHAWK RIVER FOR A SLIGHT ENHANCEMENT TO THOSE WESTERLY WINDS
THROUGH THE DAY.
WEDNESDAY NIGHT...
RIDGE OF HIGH PRESSURE WILL CREST OVER THE REGION. THIS WILL ALLOW
FOR...INITIALLY...CLEAR SKIES THROUGH THE EVENING HOURS WHICH WILL
SEND TEMPS QUICKLY DOWNWARD WITH NEAR IDEAL RADIATIONAL COOLING
/CLEAR SKIES AND LIGHT WINDS WITH A FROZEN AND PARTIAL SNOW
COVERED GROUND/. THEN WE WILL WATCH UPSTREAM CONDITIONS CLOSELY AS
STRONG PACIFIC ENERGY COMES ASHORE AND TRACKS ACROSS THE CENTER OF
THE NATION. NCEP MODEL SUITE ALONG WITH INTERNATIONAL GUIDANCE ARE
IN RATHER GOOD AGREEMENT WITH BROAD WARM ADVECTION ALOFT TO
COMMENCE OVERNIGHT WEDNESDAY INTO SUNRISE THURSDAY MORNING.
ISENTROPIC ANALYSIS ON THE 285-290K SURFACE SUPPORTS BROAD
ISENTROPIC LIFT AND SLOWLY LOWERING CPD/S TO RESULT WITH AN
INCREASE OF CLOUD COVER. THESE CLOUDS SHOULD LIMIT FURTHER
DECLINES IN THE TEMPERATURES OVERNIGHT AND MAY EVEN SEE A SLOW
REBOUND TOWARD SUNRISE.
THURSDAY...
THE AFOREMENTIONED ISENTROPIC LIFT CONTINUES THROUGH THE DAY
THURSDAY WITH A CONTINUE DECREASE IN THOSE CPD/S. THIS SHOULD
RESULT IN THE THICKENING AND LOWERING OF THE CLOUD DECK AND THE
CHANCE FOR OVERRUNNING LIGHT SNOW TO DEVELOP. WHILE MODEL QPF
SIGNALS ARE NOT SHOWING THIS ACROSS OUR REGION /THEY DO SO FURTHER
UPSTREAM/...THE COMBINATION OF CONTINUED ISENTROPIC LIFT AND LESS
THAN 30MB CPD/S...WE WILL PLACE CHC POPS ACROSS THE NORTHERN 1/2
OF THE CWFA BEGINNING BY LATE MORNING. THE BEST CHANCE FOR AN
ACCUMULATING SNOWFALL WILL LIKELY REMAIN ALONG AND NORTH OF I90
WHERE THE BEST LIFT AND MOISTURE PROFILES ARE EXPECTED AND VALUES
UP TO 1 INCH POSSIBLE. AS FOR TEMPERATURES...THE LOW LEVEL
AGEOSTROPHIC FLOW DOES INCREASE FROM THE NORTH AND THIS TOO SHOULD
LIMIT TEMPERATURES FROM GETTING OUT OF THE 20S.
THURSDAY NIGHT...
THIS WILL BE THE PERIOD OF TRANSITION TO A POTENTIAL STORM
IMPACTING THE REGION. GLOBAL MODEL TRENDS AND THE PERSISTENT ECMWF
FOR THE PAST 5 RUNS WANT TO PHASE THE NORTHERN STREAM PACIFIC
ENERGY WITH SOUTHERN STREAM WAVE/S/ ACROSS BAJA AND NORTHERN
MEXICO. LOW LEVEL SOUTHERLY JET AND MOISTURE TRANSPORT VECTORS
INCREASE RATHER RAPIDLY THURSDAY NIGHT WHERE THE CHANCE FOR LIGHT
SNOW TO INCREASE ACROSS THE REGION. GIVEN THE FORECAST WIND
TRAJECTORY AND MAGNITUDES...WE WILL FAVOR THE HIGHER TERRAIN WITH
LIKELY POPS AND HIGH CHANCE FOR THE VALLEY LOCATIONS. AS FOR
NOW...SNOWFALL AMOUNTS OF 1-2 INCHES WITH THE POSSIBILITY OF SOME
HIGHER TOTALS IN THE MOUNTAINS. GUIDANCE NUMBERS ARE FAIRLY CLOSE
AS WE LEANED MORE TOWARD THE GFS/ECMWF MOS NUMBERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HPC GUIDANCE. MOST MODELS NOW ON BOARD WITH A MAJOR WINTER EVENT
FOR THE END OF THE WEEK. LOW PRESSURE WILL BE NEAR VIRGINIA BEACH
AT THE START OF THE PERIOD...WITH SNOW ALREADY OVERSPREADING OUR
FORECAST AREA. THE LOW WILL TRACK TO SOUTH OF WESTERN NOVA SCOTIA
BY SATURDAY MORNING...INTENSIFYING RAPIDLY. A PERIOD OF RAIN OR A
SNOW MIX IS A POSSIBILITY BRIEFLY DURING THE DAY ON FRIDAY IN THE
LOWER SECTION OF THE MID HUDSON VALLEY...BUT FOR NOW WILL SAY IT IS
ALL SNOW. OTHERWISE...AN ALL-SNOW EVENT IS ANTICIPATED WITH
CONFIDENCE...WITH ACTIVITY WINDING DOWN SWIFTLY DURING THE DAY ON
FRIDAY. A FLOW TURNING NORTHERLY ENHANCED BY STRONG HIGH PRESSURE
MOVING IN BY SUNDAY ENSURES THAT WE HAVE AN ALL-SNOW EVENT BEYOND
FRIDAY AFTERNOON.
AS IT LOOKS RIGHT NOW...THE LOW IS EXPECTED TO STAY WELL ENOUGH TO
THE SOUTH...SUCH THAT 6 TO 10 INCHES OF TOTAL SNOW ACCUMULATION
LOOKS MOST REASONABLE...WITH THE GREATER AMOUNTS...OF COURSE...TO
THE SOUTH AND EAST IN OUR FORECAST AREA. MORE IS POSSIBLE...BUT SO
IS LESS...DEPENDING ON HOW THE SYSTEM EVOLVES. THIS LOOKS TO BE A
BROAD-AREA SNOW-PRODUCER.
BY SATURDAY NIGHT...SKIES WILL BE MOSTLY ON THE PARTLY CLOUDY
SIDE...WITH WINDS RAPIDLY DIMINISHING TO MAKE THE NIGHT A COLD ONE.
BUT THE REPRIEVE WILL BE BRIEF AS ANOTHER SYSTEM THREATENS THE
REGION WITH A WINTRY MIX OF PRECIPITATION FOR MONDAY/MONDAY NIGHT.
A COLD FRONT SLIDES THROUGH THE REGION...WITH TUESDAY BEGINNING A
PERIOD OF LAKE EFFECT SNOW SHOWERS...MAINLY WEST OF THE CAPITAL
REGION.
HIGH TEMPERATURES WILL RANGE FROM THE MID 20S IN THE ADIRONDACKS AND
GREENS...TO THE UPPER 30S IN THE LOWER MID HUDSON VALLEY. ON
SATURDAY...ALMOST ALL AREAS WILL FAIL TO CRACK THE FREEZING MARK.
ON SUNDAY...HOWEVER...ALMOST ALL LOCATIONS WILL MAKE IT TO AT LEAST
JUST ABOVE FREEZING. HIGHS ON MONDAY WILL RANGE FROM THE MID AND
UPPER 30S IN THE ADIRONDACKS AND GREENS...TO THE UPPER 40S IN THE
MID HUDSON VALLEY. THE COLD FRONT WILL BACK OFF TUESDAY HIGH
TEMPERATURES FROM AROUND 30 DEGREES IN THE ADIRONDACKS...TO THE MID
40S IN THE MID HUDSON VALLEY.
LOW TEMPERATURES BOTH FRIDAY AND SATURDAY NIGHTS WILL RANGE FROM
AROUND ZERO IN THE ADIRONDACKS...TO THE MID TEENS IN THE LOWER MID
HUDSON VALLEY. SUNDAY NIGHT LOWS WILL RANGE FROM THE UPPER TEENS IN
THE ADIRONDACKS...TO THE UPPER 20S IN THE LOWER MID HUDSON VALLEY.
A FURTHER MODERATION WILL TAKE PLACE FOR MONDAY NIGHT.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
WEAK HIGH PRESSURE WILL MOVE EAST OF THE REGION THIS EVENING...AS A
WEAK CLIPPER LOW MOVES INTO THE GREAT LAKES. SOME LIGHT SNOW IS
EXPECTED AT THE KALB/KPOU/KGFL/KPSF TERMINALS AS THIS SYSTEM TRACKS
ACROSS THE AREA TONIGHT. ACCUMULATIONS ARE EXPECTED TO BE VERY
LIGHT...ALTHOUGH IT IS LIKELY THAT IFR CONDITIONS MAINLY DUE TO VSBY
WITHIN THE LIGHT SNOW WILL OCCUR. THE LIGHT SNOW WILL END WEDNESDAY
MORNING AROUND OR SHORTLY AFTER SUNRISE...WITH CONDITIONS IMPROVING
TO VFR.
WINDS WILL BE NEAR CALM THROUGH AROUND SUNRISE WEDNESDAY...THEN
BECOMING WESTERLY WEDNESDAY MORNING AND INCREASING TO AROUND 5-10 KT.
OUTLOOK...
WED-THU...VFR. NO SIG WX.
THU NGT-FRI NIGHT. MVFR/IFR WITH SNOW LIKELY.
SAT...VFR...NO SIG WX.
&&
.HYDROLOGY...
WIDESPREAD HYDRO PROBLEMS ARE NOT ANTICIPATED OVER THE NEXT FEW
DAYS AS OUR COLD WEATHER CONTINUES WITH ANY PRECIPITATION IN THE
FORM OF SNOW.
SOME RIVER AND STREAM GAGES ARE EXPERIENCING ICE EFFECTS. ICE
WILL CONTINUE TO FORM AND THICKEN ON ALL BODIES OF WATER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...ELH
AVIATION...JPV
HYDROLOGY...IAA/BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
418 PM EST TUE FEB 5 2013
.SYNOPSIS...
A CLIPPER SYSTEM WILL APPROACH AND MOVE ACROSS THE REGION
TONIGHT...BRINGING SOME VERY LIGHT SNOW TO THE AREA. FAIR WEATHER
IS EXPECTED MID WEEK AS HIGH PRESSURE BUILDS IN. A WIDESPREAD
SNOWFALL IS ANTICIPATED FOR THE LATER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
PER THE H2O VAPOR LOOP ANALYSIS...A FAST MOVING SHORT WAVE WAS
CROSSING THE LOWER GREAT LAKES REGION THIS AFTERNOON. REGIONAL
RADARS SHOW A SCT-BKN LINE OF PRECIPITATION THAT WAS ASSOCIATED
WITH WEAK FORCING. THIS FORCING IS EXPECTED TO REMAIN QUASI-
FOCUSED AS IT MIGRATES ACROSS THE CWFA. EXPERIENTIAL FORECAST
REFLECTIVITIES LEAD BY THE HRRR ALL SUGGEST A SCATTERED NATURE TO
THE SNOWFALL TONIGHT. ALONG WITH THE MOS GUIDANCE...WE WILL DROP
BACK POPS TO THE HIGH CHC-SCT CATEGORY WITH ACCUMULATIONS LESS
THAN 1 INCH FOR MOST LOCATIONS. THE CLOUD COVER WILL LIKELY REMAIN
EXTENSIVE OVERNIGHT WHICH SHOULD KEEP TEMPS A LITTLE MILDER THAN
THIS MORNINGS VALUES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY...
MINOR LAKE EFFECT SNOW EVENT WILL BE POSSIBLE FOR PORTIONS OF THE
MOHAWK VALLEY AND ADIRONDACKS IN THE MORNING BEFORE THOSE
INVERSION HEIGHTS COLLAPSE TOWARD NOON. OTHERWISE...VARIABLE CLOUD
COVER WILL BEGIN TO SLOWLY IMPROVE THROUGH THE DAY AS TEMPERATURES
CLIMB INTO THE LOW-MID 30S FOR VALLEY LOCATIONS AND 20S ELSEWHERE.
WINDS WILL BE RATHER GUSTY THROUGH THE DAY AS WE MIX UP TO 30KT
MAGNITUDES. FURTHERMORE...THOSE WINDS MAY GET FUNNELED DOWN THE
MOHAWK RIVER FOR A SLIGHT ENHANCEMENT TO THOSE WESTERLY WINDS
THROUGH THE DAY.
WEDNESDAY NIGHT...
RIDGE OF HIGH PRESSURE WILL CREST OVER THE REGION. THIS WILL ALLOW
FOR...INITIALLY...CLEAR SKIES THROUGH THE EVENING HOURS WHICH WILL
SEND TEMPS QUICKLY DOWNWARD WITH NEAR IDEAL RADIATIONAL COOLING
/CLEAR SKIES AND LIGHT WINDS WITH A FROZEN AND PARTIAL SNOW
COVERED GROUND/. THEN WE WILL WATCH UPSTREAM CONDITIONS CLOSELY AS
STRONG PACIFIC ENERGY COMES ASHORE AND TRACKS ACROSS THE CENTER OF
THE NATION. NCEP MODEL SUITE ALONG WITH INTERNATIONAL GUIDANCE ARE
IN RATHER GOOD AGREEMENT WITH BROAD WARM ADVECTION ALOFT TO
COMMENCE OVERNIGHT WEDNESDAY INTO SUNRISE THURSDAY MORNING.
ISENTROPIC ANALYSIS ON THE 285-290K SURFACE SUPPORTS BROAD
ISENTROPIC LIFT AND SLOWLY LOWERING CPD/S TO RESULT WITH AN
INCREASE OF CLOUD COVER. THESE CLOUDS SHOULD LIMIT FURTHER
DECLINES IN THE TEMPERATURES OVERNIGHT AND MAY EVEN SEE A SLOW
REBOUND TOWARD SUNRISE.
THURSDAY...
THE AFOREMENTIONED ISENTROPIC LIFT CONTINUES THROUGH THE DAY
THURSDAY WITH A CONTINUE DECREASE IN THOSE CPD/S. THIS SHOULD
RESULT IN THE THICKENING AND LOWERING OF THE CLOUD DECK AND THE
CHANCE FOR OVERRUNNING LIGHT SNOW TO DEVELOP. WHILE MODEL QPF
SIGNALS ARE NOT SHOWING THIS ACROSS OUR REGION /THEY DO SO FURTHER
UPSTREAM/...THE COMBINATION OF CONTINUED ISENTROPIC LIFT AND LESS
THAN 30MB CPD/S...WE WILL PLACE CHC POPS ACROSS THE NORTHERN 1/2
OF THE CWFA BEGINNING BY LATE MORNING. THE BEST CHANCE FOR AN
ACCUMULATING SNOWFALL WILL LIKELY REMAIN ALONG AND NORTH OF I90
WHERE THE BEST LIFT AND MOISTURE PROFILES ARE EXPECTED AND VALUES
UP TO 1 INCH POSSIBLE. AS FOR TEMPERATURES...THE LOW LEVEL
AGEOSTROPHIC FLOW DOES INCREASE FROM THE NORTH AND THIS TOO SHOULD
LIMIT TEMPERATURES FROM GETTING OUT OF THE 20S.
THURSDAY NIGHT...
THIS WILL BE THE PERIOD OF TRANSITION TO A POTENTIAL STORM
IMPACTING THE REGION. GLOBAL MODEL TRENDS AND THE PERSISTENT ECMWF
FOR THE PAST 5 RUNS WANT TO PHASE THE NORTHERN STREAM PACIFIC
ENERGY WITH SOUTHERN STREAM WAVE/S/ ACROSS BAJA AND NORTHERN
MEXICO. LOW LEVEL SOUTHERLY JET AND MOISTURE TRANSPORT VECTORS
INCREASE RATHER RAPIDLY THURSDAY NIGHT WHERE THE CHANCE FOR LIGHT
SNOW TO INCREASE ACROSS THE REGION. GIVEN THE FORECAST WIND
TRAJECTORY AND MAGNITUDES...WE WILL FAVOR THE HIGHER TERRAIN WITH
LIKELY POPS AND HIGH CHANCE FOR THE VALLEY LOCATIONS. AS FOR
NOW...SNOWFALL AMOUNTS OF 1-2 INCHES WITH THE POSSIBILITY OF SOME
HIGHER TOTALS IN THE MOUNTAINS. GUIDANCE NUMBERS ARE FAIRLY CLOSE
AS WE LEANED MORE TOWARD THE GFS/ECMWF MOS NUMBERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HPC GUIDANCE. MOST MODELS NOW ON BOARD WITH A MAJOR WINTER EVENT
FOR THE END OF THE WEEK. LOW PRESSURE WILL BE NEAR VIRGINIA BEACH
AT THE START OF THE PERIOD...WITH SNOW ALREADY OVERSPREADING OUR
FORECAST AREA. THE LOW WILL TRACK TO SOUTH OF WESTERN NOVA SCOTIA
BY SATURDAY MORNING...INTENSIFYING RAPIDLY. A PERIOD OF RAIN OR A
SNOW MIX IS A POSSIBILITY BRIEFLY DURING THE DAY ON FRIDAY IN THE
LOWER SECTION OF THE MID HUDSON VALLEY...BUT FOR NOW WILL SAY IT IS
ALL SNOW. OTHERWISE...AN ALL-SNOW EVENT IS ANTICIPATED WITH
CONFIDENCE...WITH ACTIVITY WINDING DOWN SWIFTLY DURING THE DAY ON
FRIDAY. A FLOW TURNING NORTHERLY ENHANCED BY STRONG HIGH PRESSURE
MOVING IN BY SUNDAY ENSURES THAT WE HAVE AN ALL-SNOW EVENT BEYOND
FRIDAY AFTERNOON.
AS IT LOOKS RIGHT NOW...THE LOW IS EXPECTED TO STAY WELL ENOUGH TO
THE SOUTH...SUCH THAT 6 TO 10 INCHES OF TOTAL SNOW ACCUMULATION
LOOKS MOST REASONABLE...WITH THE GREATER AMOUNTS...OF COURSE...TO
THE SOUTH AND EAST IN OUR FORECAST AREA. MORE IS POSSIBLE...BUT SO
IS LESS...DEPENDING ON HOW THE SYSTEM EVOLVES. THIS LOOKS TO BE A
BROAD-AREA SNOW-PRODUCER.
BY SATURDAY NIGHT...SKIES WILL BE MOSTLY ON THE PARTLY CLOUDY
SIDE...WITH WINDS RAPIDLY DIMINISHING TO MAKE THE NIGHT A COLD ONE.
BUT THE REPRIEVE WILL BE BRIEF AS ANOTHER SYSTEM THREATENS THE
REGION WITH A WINTRY MIX OF PRECIPITATION FOR MONDAY/MONDAY NIGHT.
A COLD FRONT SLIDES THROUGH THE REGION...WITH TUESDAY BEGINNING A
PERIOD OF LAKE EFFECT SNOW SHOWERS...MAINLY WEST OF THE CAPITAL
REGION.
HIGH TEMPERATURES WILL RANGE FROM THE MID 20S IN THE ADIRONDACKS AND
GREENS...TO THE UPPER 30S IN THE LOWER MID HUDSON VALLEY. ON
SATURDAY...ALMOST ALL AREAS WILL FAIL TO CRACK THE FREEZING MARK.
ON SUNDAY...HOWEVER...ALMOST ALL LOCATIONS WILL MAKE IT TO AT LEAST
JUST ABOVE FREEZING. HIGHS ON MONDAY WILL RANGE FROM THE MID AND
UPPER 30S IN THE ADIRONDACKS AND GREENS...TO THE UPPER 40S IN THE
MID HUDSON VALLEY. THE COLD FRONT WILL BACK OFF TUESDAY HIGH
TEMPERATURES FROM AROUND 30 DEGREES IN THE ADIRONDACKS...TO THE MID
40S IN THE MID HUDSON VALLEY.
LOW TEMPERATURES BOTH FRIDAY AND SATURDAY NIGHTS WILL RANGE FROM
AROUND ZERO IN THE ADIRONDACKS...TO THE MID TEENS IN THE LOWER MID
HUDSON VALLEY. SUNDAY NIGHT LOWS WILL RANGE FROM THE UPPER TEENS IN
THE ADIRONDACKS...TO THE UPPER 20S IN THE LOWER MID HUDSON VALLEY.
A FURTHER MODERATION WILL TAKE PLACE FOR MONDAY NIGHT.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
WEAK HIGH PRESSURE WILL MOVE EAST OF THE REGION THIS EVENING...AS A
WEAK CLIPPER LOW MOVES INTO THE GREAT LAKES. SOME LIGHT SNOW IS
EXPECTED AT THE KALB/KPOU/KGFL/KPSF TERMINALS AS THIS SYSTEM TRACKS
ACROSS THE AREA TONIGHT. ACCUMULATIONS ARE EXPECTED TO BE VERY
LIGHT...ALTHOUGH IT IS LIKELY THAT IFR CONDITIONS MAINLY DUE TO VSBY
WITHIN THE LIGHT SNOW WILL OCCUR. THE LIGHT SNOW WILL END WEDNESDAY
MORNING AROUND OR SHORTLY AFTER SUNRISE...WITH CONDITIONS IMPROVING
TO VFR.
WINDS WILL BE NEAR CALM THROUGH AROUND SUNRISE WEDNESDAY...THEN
BECOMING WESTERLY WEDNESDAY MORNING AND INCREASING TO AROUND 5-10 KT.
OUTLOOK...
WED-THU...VFR. NO SIG WX.
THU NGT-FRI NIGHT. MVFR/IFR WITH SNOW LIKELY.
SAT...VFR...NO SIG WX.
&&
.HYDROLOGY...
WIDESPREAD HYDRO PROBLEMS ARE NOT ANTICIPATED OVER THE NEXT FEW
DAYS AS OUR COLD WEATHER CONTINUES WITH ANY PRECIPITATION IN THE
FORM OF SNOW.
SOME RIVER AND STREAM GAGES ARE EXPERIENCING ICE EFFECTS. ICE
WILL CONTINUE TO FORM AND THICKEN ON ALL BODIES OF WATER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...ELH
AVIATION...JPV
HYDROLOGY...IAA/BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EST TUE FEB 5 2013
.UPDATE (REST OF TODAY AND TONIGHT)...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A RATHER UNAMPLIFIED UPPER
LEVEL PATTERN ACROSS THE CONUS. OVERALL PATTERN CONSISTS OF BROAD
RIDGING OVER MUCH OF THE PACIFIC COAST/INTER-MOUNTAIN
WEST...FOLLOWED DOWNSTREAM BY BROAD LONGWAVE TROUGHING OVER THE
EAST. OUR REGION RESIDES SOUTH OF THIS EASTERN TROUGH UNDER A NEARLY
ZONAL FLOW PATTERN. SKIES ARE GENERALLY CLEAR OVER OUR ZONES THIS
MORNING...ALTHOUGH DEEPER MOISTURE AND CLOUDS ARE LOCATED JUST OFF
TO OUR NORTH AND WEST TOWARD THE PANHANDLE/BIG BEND. SOME OF THIS
MOISTURE WILL OVERSPREAD THE NATURE COAST THE REST OF THIS
AFTERNOON...ESPECIALLY NORTH OF PASCO/HERNANDO COUNTIES.
AT THE SURFACE...1020MB HIGH PRESSURE IS CENTERED ALMOST DIRECTLY
OVER THE FL PENINSULA KEEPING THE LOCAL GRADIENT AND RESULTING FLOW
WEAK AND VARIABLE IN NATURE.
REST OF THE AFTERNOON...PARTLY/MOSTLY CLOUDY SKIES NORTH AND MOSTLY
SUNNY SKIES SOUTH WILL PROMOTE GOOD DIURNAL MIXING DESPITE THE WEAK
BOUNDARY LAYER FLOW...AND RESULT IN PLEASANT AFTERNOON TEMPERATURES
OF LOWER TO MIDDLE 70S NORTH AND UPPER 70S TO AROUND 80 SOUTH. THE
WEAK GRADIENT AND DECENT TEMPERATURE REBOUND HAS ALREADY FORCED A
FEEBLE SEA-BREEZE CIRCULATION. THIS ONSHORE FLOW OFF THE RELATIVELY
COOLER SHELF WATERS WILL KEEP TEMPERATURES DOWN A FEW DEGREES AT THE
BEACHES.
.SHORT TERM (TONIGHT THROUGH FRIDAY)...
TONIGHT...THE ARRIVAL OF AN IMPULSE WITHIN THE ZONAL FLOW AND
RESULTING WEAK SYNOPTIC FORCING/MOISTURE ADVECTION WILL LEAD TO A
FEW SHOWERS OVER FAR NORTHERN ZONES...MAINLY LEVY/CITRUS COUNTIES.
ALL GUIDANCE MEMBERS SHOW LIMITED QPF...AND SO NOT ANTICIPATING ANY
OF THESE SHOWERS TO BE OF SIGNIFICANT IMPACT. THE REST OF THE AREA
WILL SEE A SLOW INCREASE IN CLOUDS...BUT WITH DRY AND RAIN-FREE
CONDITIONS CONTINUING AT THE SURFACE. TEMPERATURES WILL BE ON THE
REBOUND COMPARED TO PREVIOUS NIGHTS WITH MOST LOCATIONS HOLDING IN
THE 50S. A FEW OF THE COLDER LOCATIONS MAY BRIEFLY DROP INTO THE
UPPER 40S ACROSS THE INTERIOR NATURE COAST...BUT NOT UNTIL LATE
NIGHT.
WEDNESDAY/WEDNESDAY NIGHT...
WEAK IMPULSE WILL QUICKLY PASS TO OUR EAST DURING THE MORNING HOURS.
MAY STILL SEE A FEW MORNING SHOWERS UP OVER THE NATURE COAST...BUT
THESE SHOULD GENERALLY END BY MIDDAY WITH THE LOSS OF ANY SYNOPTIC
FORCING. IN FACT...HEIGHT FALLS TO OUR WEST ASSOCIATED WITH AN
APPROACHING SYSTEM OVER THE SOUTHERN PLAINS WILL HELP TO FORCE MINOR
DOWNSTREAM HEIGHT RISES OVER THE EASTERN GULF/FL PENINSULA WHICH
SHOULD FURTHER HELP TO SUPPRESS ANY LINGERING SHOWERS. SYSTEM TO OUR
WEST WILL BEGIN TO SPREAD EASTWARD ALONG THE NORTHERN GULF COAST
DURING WEDNESDAY NIGHT. A WARM FRONTAL FEATURE WILL EXTEND ALONG THE
I-10 CORRIDOR FROM LOW PRESSURE NEAR THE TEXAS COAST. THIS
CONFIGURATION SHOULD KEEP THE BEST LOW LEVEL ISENTROPIC LIFT OVER
THIS FRONT TO OUR NORTH. PERHAPS A FEW SHOWERS WILL BE POSSIBLE UP
TOWARD LEVY COUNTY...BUT ESSENTIALLY GOING WITH A DRY FORECAST
FORECAST AREA-WIDE. SEASONABLY WARM TEMPERATURES ONCE AGAIN
WEDNESDAY WITH MID 70S NORTH AND UPPER 70S TO LOWER 80S SOUTH OF THE
I-4 CORRIDOR. THE OVERNIGHT LOWS WILL CONTINUE TO MODERATE A FEW
DEGREES KEEPING ALL AREAS ABOVE 50.
THURSDAY/THURSDAY NIGHT...
UPPER SHORTWAVE AND ASSOCIATED SURFACE LOW WILL LIFT FROM NEAR THE
MS DELTA TO SOUTHERN AL/GA DURING THE DAY. SYNOPTIC WARM FRONT LIFTS
INTO GA DURING THE DAY CONTINUING TO KEEP THE BEST OVERRUNNING AND
ISENTROPIC RAIN CHANCES TO THE NORTH OF OUR ZONES. ASSOCIATED COLD
FRONT WILL SLOWLY BE APPROACHING FROM THE WEST AND NORTHWEST...BUT
REALLY SHOULD NOT PRESENT MUCH CHANCE FOR RAIN OVER OUR AREA UNTIL
LATE IN THE DAY...AND EVEN THEN...MAINLY NORTH OF TAMPA BAY. THIS
PATTERN WILL CONTINUE INTO THURSDAY NIGHT AS THE SURFACE LOW LIFTS
UP THE EASTERN SEABOARD AND THE TRAILING FRONT LAYS OUT AND BECOMES
QUASI-STATIONARY OVER THE NORTHEAST GULF/NORTHERN PENINSULA. BEST
FOCUS FOR SHOWERS WILL STAY OVER OUR NORTHERN ZONES...HOWEVER WITH
NO SIGNIFICANT SYNOPTIC SUPPORT LEFT...THIS ACTIVITY SHOULD BE
RATHER LIMITED.
FRIDAY...ONE FINAL IMPULSE MOVING THROUGH THE SOUTHEAST HELPS TO
GIVE THE FRONT A PUSH SOUTH INTO THE CENTRAL PENINSULA. THIS
PROGRESSION WILL ONCE AGAIN INCREASE LOW LEVEL FOCUS AND EXPECT
A BROKEN BAND OF SHOWERS TO PUSH SOUTH ALONG AND AHEAD OF THE FRONT
THROUGH THE DAY.
&&
.LONG TERM (FRIDAY NIGHT THROUGH NEXT MONDAY)...
LOW PRESSURE WILL BE DEVELOPING AND LIFTING NE JUST NORTH OF THE
REGION TO START THE PERIOD AS WEAK HIGH PRESSURE RIDGES ACROSS SOUTH
FLORIDA. THE COLD FRONT WITH THIS LOW WILL MOVE THROUGH THE AREA
LATE FRIDAY/FRIDAY NIGHT WITH A FEW SHOWERS POSSIBLE WITH IT. HIGH
PRESSURE WILL BUILD INTO THE AREA BEHIND THE FRONT FOR SATURDAY AND
BRING SOME COOLER AND DRIER AIR. HIGH PRESSURE WILL THEN CONTINUE TO
RIDGE ACROSS THE AREA THROUGH MONDAY. TEMPS WILL REMAIN ABOVE NORMAL
THROUGH THE PERIOD WITH HIGHS IN THE MID 70S TO LOWER 80S AND LOWS
IN THE MID 50S TO MID 60S...FALLING INTO THE UPPER 40S TO UPPER 50S
BEHIND THE FRONT.
&&
.AVIATION...
MAINLY VFR NEXT 24 HOURS. SOME INCREASING MID LEVEL CLOUDS BETWEEN
8KFT AND 15KFT TODAY AND TONIGHT. WINDS WILL BE LIGHT WITH AFTERNOON
BAY AND GULF BREEZES THROUGH THIS EVENING. BEST CHANCE FOR MVFR OR
IFR VISIBILITIES IN FOG WILL BE AT PGD BETWEEN 09Z AND 13Z.
&&
.MARINE...
AN ATLANTIC RIDGE OF HIGH PRESSURE CONTINUES OVER THE AREA PROVIDING
LIGHT WINDS AND WAVES. BAY AND INLAND WATERS WILL REMAIN RELATIVELY
CALM THANKS TO LIGHT WINDS. A COLD FRONT WILL APPROACH THE AREA LATE
IN THE WEEK...BRINGING HIGHER WINDS AND SEAS TO THE WATERS. SHOWERS
ARE POSSIBLE IN AND AROUND THE WATERS WITH THE PASSING FRONTAL
SYSTEM LATER IN THE WEEK. SEAS AND WINDS SHOULD BEGIN TO DIMINISH
LATE IN THE WEEKEND.
&&
.FIRE WEATHER...
DRY WEATHER WILL GRADUALLY BE REPLACED BY INCREASING MOISTURE FROM
THE SOUTHEAST. THERE COULD BE A FEW SHOWERS NORTH OF TAMPA BAY
TONIGHT AND WEDNESDAY. A COLD FRONT WILL BRING A CHANCE OF SHOWERS
TO MUCH OF THE AREA BEGINNING THURSDAY AFTERNOON AND CONTINUING
THROUGH FRIDAY. AFTER TODAY...CRITICAL HUMIDITIES ARE NOT EXPECTED
THROUGH THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 59 78 62 78 / 10 10 10 10
FMY 57 81 60 82 / 10 10 10 10
GIF 51 78 57 80 / 10 10 10 10
SRQ 54 77 61 78 / 10 10 10 10
BKV 49 78 54 80 / 10 10 10 20
SPG 59 76 63 77 / 10 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING UNTIL 6 PM EST THIS EVENING FOR LEE-
PINELLAS-POLK.
BEACH HAZARDS STATEMENT THROUGH THURSDAY EVENING FOR
CHARLOTTE-LEE-SARASOTA.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM...MROCZKA
MARINE...GARCIA/MROCZKA
FIRE WEATHER...JILLSON/MROCZKA
LONG TERM...COLSON
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
137 PM EST TUE FEB 5 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY...AREA OF LIGHT RAIN AND
DRIZZLE HAS ENDED OVER THE AREA EARLY THIS AFTERNOON WITH ANOTHER
AREA OVER THE FL PANHANDLE. THIS RAIN SHOULD MOVE EAST ACROSS THE
AREA TONIGHT WITH RUC MODEL HAVING A GOOD HANDLE ON PRECIP TRENDS.
MODELS SIMILAR IN SHOWING A STRONG SHORTWAVE WITH AN ASSOCIATED
SURFACE LOW/WARM FRONT LIFTING INTO S GA ON THURSDAY. STRONGEST LIFT
AND THE BEST CHANCE OF RAIN WILL BE THURSDAY INTO THURSDAY NIGHT.
TRAILING COLD FRONT WILL MOVE THROUGH BRINGING ANOTHER RAIN CHANCE
ON FRIDAY. INSTABILITY WILL BE WEAK BUT STRONG DYNAMICS SHOULD
RESULT IN AT LEAST ISOLATED THUNDERSTORMS. PATCHY FOG WILL BE POSSIBLE
THE NEXT TWO NIGHT AS LOW LEVEL MOISTURE INCREASES. TEMPERATURES
WILL BE ABOUT 5 TO 10 DEGREES ABOVE AVERAGE THROUGH FRIDAY.
.LONG TERM...SATURDAY THROUGH TUESDAY...LARGE AND STRONG SURFACE
HIGH WILL LOCATED ALONG THE EASTERN SEABOARD WHICH WILL PRODUCE A
STRONG NE FLOW AND CHANCE OF COASTAL SHOWERS THIS WEEKEND. THE
HIGH WILL MOVE OFF THE EAST COAST MONDAY WITH VEERING WINDS AND
WARMING TEMPERATURES. ANOTHER COLD FRONT WILL MOVE INTO THE AREA
TUESDAY BRINGING THE NEXT CHANCE OF RAIN. AFTER NEAR NORMAL
TEMPERATURES ON SATURDAY TEMPERATURES WILL RISE BACK ABOVE AVERAGE
EARLY NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH FOR THIS TAF PERIOD. HAVE MVFR
VISIBILITY WITH VCSH AT GNV AND VQQ AFTER 06Z. GNV IS ONLY SITE
WITH VCSH THIS AFTERNOON...THEN ALL TAF SITES HAVE VCSH TONIGHT.
&&
.MARINE...
QUIET CONDS ARE NOTED OVER THE WATERS WITH SW/W WINDS OFFSHORE AND
SEABREEZE HAS PRODUCED ENE WINDS AT SAUF1. ONSHORE WINDS DEVELOP
WED/THU AS HIGH PRESSURE BUILDS NNE OF THE REGION. WINDS WILL
INCREASE AHEAD OF A LOW PRESSURE SYSTEM THU NIGHT/FRI AND CONTINUE
15-20 KT FOLLOWING A TRAILING COLD FRONT THIS WEEKEND. EXPECT SCEC
CONDITIONS FOR MUCH OF THIS PERIOD AND SCA CONDS WILL BE POSSIBLE
OFFSHORE THU NIGHT.
RIP CURRENTS: LOW RISK AGAIN WEDNESDAY.
&&
.FIRE WEATHER...
MOISTURE HAS INCREASED OVER THE NORTHERN TWO-THIRDS OF THE FCST
AREA WHILE DRY CONDITIONS ARE CONTINUE OVER THE SE PORTION. THIS
AREA WILL MOISTEN BY WED WITH RH`S ABOVE CRITICAL LEVELS THROUGH
THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 49 74 54 69 / 30 10 20 50
SSI 53 69 54 68 / 20 20 30 60
JAX 49 75 55 75 / 20 10 20 50
SGJ 52 70 58 76 / 20 0 20 30
GNV 49 75 53 77 / 20 20 20 30
OCF 51 76 55 80 / 20 20 20 20
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
ZIBURA/TRABERT/WALKER
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1040 AM EST TUE FEB 5 2013
.UPDATE (REST OF TODAY AND TONIGHT)...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A RATHER UNAMPLIFIED UPPER
LEVEL PATTERN ACROSS THE CONUS THIS MORNING. OVERALL PATTERN
CONSISTS OF BROAD RIDGING OVER MUCH OF THE PACIFIC
COAST/INTER-MOUNTAIN WEST...FOLLOWED DOWNSTREAM BY BROAD LONGWAVE
TROUGHING OVER THE EAST. OUR REGION RESIDES SOUTH OF THIS EASTERN
TROUGH UNDER A NEARLY ZONAL FLOW PATTERN. SKIES ARE GENERALLY CLEAR
OVER OUR ZONES THIS MORNING...ALTHOUGH DEEPER MOISTURE AND CLOUDS
ARE LOCATED JUST OFF TO OUR NORTH AND WEST TOWARD THE PANHANDLE/BIG
BEND. SOME OF THIS MOISTURE IS PROGGED TO OVERSPREAD THE NATURE
COAST THIS AFTERNOON...ESPECIALLY NORTH OF PASCO/HERNANDO COUNTIES.
AT THE SURFACE...1020MB HIGH PRESSURE IS CENTERED ALMOST DIRECTLY
OVER THE FL PENINSULA KEEPING THE LOCAL GRADIENT AND RESULTING FLOW
WEAK AND VARIABLE IN NATURE.
REST OF TODAY...PARTLY SUNNY SKIES NORTH AND MOSTLY SUNNY SKIES
SOUTH WILL PROMOTE GOOD DIURNAL MIXING DESPITE THE WEAK BOUNDARY
LAYER FLOW...AND RESULT IN PLEASANT AFTERNOON TEMPERATURES OF LOWER
TO MIDDLE 70S NORTH AND UPPER 70S SOUTH. THE WEAK GRADIENT AND
DECENT TEMPERATURE REBOUND SHOULD FORCE A FEEBLE SEA-BREEZE
CIRCULATION BY MID AFTERNOON. THIS ONSHORE FLOW OFF THE RELATIVELY
COOLER SHELF WATERS WILL KEEP TEMPERATURES DOWN A FEW DEGREES AT THE
BEACHES.
TONIGHT...THE ARRIVAL OF AN IMPULSE WITHIN THE ZONAL FLOW AND
RESULTING WEAK SYNOPTIC FORCING/MOISTURE ADVECTION MAY LEAD TO A FEW
SHOWERS OVER FAR NORTHERN ZONES...MAINLY LEVY COUNTY. ALL GUIDANCE
MEMBERS SHOW LIMITED QPF...AND SO NOT ANTICIPATING ANY OF THESE
SHOWERS TO BE OF SIGNIFICANT IMPACT. THE REST OF THE AREA WILL SEE A
SLOW INCREASE IN CLOUDS...BUT WITH DRY AND RAIN-FREE CONDITIONS
CONTINUING AT THE SURFACE. TEMPERATURES WILL BE ON THE REBOUND
COMPARED TO PREVIOUS NIGHTS WITH MOST LOCATIONS HOLDING IN THE 50S.
A FEW OF THE COLDER LOCATIONS MAY BRIEFLY DROP INTO THE MID/UPPER
40S ACROSS THE INTERIOR NATURE COAST...BUT NOT UNTIL LATE NIGHT.
&&
.AVIATION...
VFR NEXT 24 HOURS. SOME INCREASING MID LEVEL CLOUDS BETWEEN 10KFT
AND 15KFT TODAY AND TONIGHT. WINDS WILL BE LIGHT WITH AFTERNOON BAY
AND GULF BREEZES.
&&
.MARINE...
A RELAXED PRESSURE GRADIENT WILL KEEP WINDS AND SEAS BELOW CAUTION
OR ADVISORY CRITERIA FOR THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 58 77 62 / 10 10 10 10
FMY 79 58 81 61 / 10 10 10 10
GIF 77 55 79 59 / 10 10 10 10
SRQ 75 55 76 60 / 10 10 10 10
BKV 75 48 78 53 / 10 10 10 10
SPG 74 60 75 64 / 10 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING
FOR LEE-PINELLAS-POLK.
BEACH HAZARDS STATEMENT THROUGH THURSDAY EVENING FOR
CHARLOTTE-LEE-SARASOTA.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
620 AM EST Tue Feb 5 2013
.NEAR TERM [through This Afternoon]...
Updated at: 520 AM EST
Rain continues to arrive in the western part of our forecast area
faster than model guidance has projected. Therefore, the PoPs and
weather grids have been updated to reflect about 2-4 hour faster
progression. The heaviest rain (per EVX/MOB radar and surface
observations) appears to be from MOB-DTS & offshore of those areas
as of 10z. Not surprisingly, this is the location that objective RUC
analysis places the strongest isentropic ascent (in the 295-305K
planes) and lowest condensation pressure deficits, as well as the
nose of the strongest low-level moisture transport. By 18z today,
these features are more centrally located in our forecast area, and
that is when the highest PoPs were focused. By mid-late afternoon,
we should see a decrease in the intensity and coverage of rain.
Overall, it looks like a good day to take the umbrella - especially
in the Florida Panhandle from Tallahassee and points west.
The latest runs of the RUC (05.07z) and our local TAE-WRF (05.06z)
keep temperatures in the mid-upper 50s across much of the western
two-thirds of our forecast area through the day. This doesn`t seem
entirely unreasonable with dense cloud cover and steady rain.
Therefore, the highs were nudged down another degree or two, but not
quite to what is portrayed on the RUC and WRF.
&&
.SHORT TERM [Tonight Through Thursday]...
The large scale longwave pattern commences tonight relatively un-
amplified and progressive especially in moist Srn stream
highlighted by weak ridging Wrn states and very weak WSW to zonal
flow over Ern states. This will continue to allow several
shortwaves to traverse Ewd in WLY flow. Next shortwave is weak and
is currently moving NE off TX/LA coast will move across the SE
states/vort and exit east tonight. At the surface, low lifting
across NE states and aided by shortwave brings trailing quasi-
stnry weak surface trough to near coast or into extreme Nrn Gulf
of Mex. Weak surface wave appears to possibly develop at tail of
front slowing it down. With deep layer WSW flow will go with
50-20% SW-NE pop gradient which overlays well with MAV and local
confidence tool. Confidence tool hints at isold TSRA wrn waters
but for now will exclude to match our neighbors. Under light
winds, SREF, NAM and other guidance all show ample fog along
boundary. Temperatures will likely be held down somewhat by
extensive cloud cover, keeping highs in the upper 40s to around 50
for most areas.
These unsettled conditions will linger over the water into
Wednesday as the boundary is expected to move very little.
Without significant forcing, the stalled front may provide just
enough lift for 10-20% N-S showers over land, 30% over water. The
boundary should dissipate by Wed night as a large surface high
builds Ewd across Ern states leaving a fairly strong ridge over SE
region into Wed night. Then another rain event develops. Next
shortwave a little stronger and moves NE off TX/LA coast Ewd in
near zonal flow beginning on Wed. As a result, next surface low
develops over TX and moves thru SE region with trailing front
elongating Gulf Coast Thurs thru late Thurs night. However, models
strongly disagree on timing and intensity of system. ECMWF and NAM
quicker and with higher QPF than GFS in moving low solutions are
closer than 24hrs ago. Forecast a blend of ECMWF and confidence
tool. In either case, isentropic lift induced rain commences Wed
night west half of CFWA spreading SEWD on Thurs before exiting
shortwave lifts frontal trough northward and surface moisture E/NE
of local area by early Fri with low to outer banks of NC.
Will go with 40-20% W-E pops Wed night and 60-20% NW-SE gradient on
Thurs. Gradual warming trend. Min/Max temps are Wed Night 50 to 55
degrees and on Wed and Thurs 70 to 75 degrees.
&&
.LONG TERM [Thursday Night through Monday]...
As the extended period begins, the upper flow is forecast to be
largely zonal. However, a shortwave within this flow will be
pushing through Texas, with southwesterly flow overrunning the
stalled frontal boundary along the northern Gulf coast. Isentropic
lift is forecast to intensity along this boundary on Thursday,
allowing for a broad area of showers to push north into the
forecast area. At this time, it appears the instability will not
be sufficient for thunder, as the sfc boundary remain very close
to the coast.
By Friday, the shortwave will push off to the east. However, the
sfc front is expected to remain stationary or push just south of
the region. This may allow for a few showers even during the day
on Thursday.
By Saturday, high pressure will nose down the eastern seaboard
and push the boundary farther south of the area. This should keep
the region dry through the weekend. With the zonal flow aloft and
no source of cold air, temperatures are expected to remain above
normal through the end of the week.
&&
.AVIATION [through 12z Wednesday]...
Updated at: 620 AM EST
The outlook for the terminals and surrounding area through much of
the daytime hours is still VFR with periodic -RA. Winds will be
light out of a generally southerly direction. In the evening, CIGS
should trend down into the MVFR range, with the possibility of some
fog and IFR CIGS or visibility developing overnight. Model guidance
differs on the timing of these trends, but there is overall
agreement on the deteriorating flight categories overnight.
&&
.MARINE...
A weak surface trough will settle along the northern Gulf Coast
thru early Wed. This will keep winds and seas mostly low and
onshore. By Thursday, a stronger storm system will approach from
the west and increase winds to near cautionary levels. Light to
moderate offshore flow will return on Friday before becoming
easterly into the weekend.
&&
.FIRE WEATHER...
Increased moisture and rain chances are expected for much of the
rest of the work week. Therefore, red flag conditions are not
expected over any of the area.
&&
.HYDROLOGY...
Despite increased rain chances this week, rainfall totals are
expected to remain low, with minimal impact on area rivers and
streams.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 63 53 71 55 73 / 70 40 20 30 50
Panama City 64 56 69 57 69 / 90 50 20 40 60
Dothan 63 49 73 55 70 / 50 40 10 30 60
Albany 64 48 73 53 70 / 30 30 10 20 60
Valdosta 69 52 71 55 74 / 30 30 20 20 40
Cross City 71 51 74 53 76 / 20 30 30 20 20
Apalachicola 65 56 68 57 68 / 80 40 20 40 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Block
LONG TERM...Camp
AVIATION...Lamers
MARINE...Block
FIRE WEATHER...Lamers
HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
522 AM EST Tue Feb 5 2013
.NEAR TERM [through This Afternoon]...
Updated at: 520 AM EST
Rain continues to arrive in the western part of our forecast area
faster than model guidance has projected. Therefore, the PoPs and
weather grids have been updated to reflect about 2-4 hour faster
progression. The heaviest rain (per EVX/MOB radar and surface
observations) appears to be from MOB-DTS & offshore of those areas
as of 10z. Not surprisingly, this is the location that objective RUC
analysis places the strongest isentropic ascent (in the 295-305K
planes) and lowest condensation pressure deficits, as well as the
nose of the strongest low-level moisture transport. By 18z today,
these features are more centrally located in our forecast area, and
that is when the highest PoPs were focused. By mid-late afternoon,
we should see a decrease in the intensity and coverage of rain.
Overall, it looks like a good day to take the umbrella - especially
in the Florida Panhandle from Tallahassee and points west.
The latest runs of the RUC (05.07z) and our local TAE-WRF (05.06z)
keep temperatures in the mid-upper 50s across much of the western
two-thirds of our forecast area through the day. This doesn`t seem
entirely unreasonable with dense cloud cover and steady rain.
Therefore, the highs were nudged down another degree or two, but not
quite to what is portrayed on the RUC and WRF.
&&
.SHORT TERM [Tonight Through Thursday]...
The large scale longwave pattern commences tonight relatively un-
amplified and progressive especially in moist Srn stream
highlighted by weak ridging Wrn states and very weak WSW to zonal
flow over Ern states. This will continue to allow several
shortwaves to traverse Ewd in WLY flow. Next shortwave is weak and
is currently moving NE off TX/LA coast will move across the SE
states/vort and exit east tonight. At the surface, low lifting
across NE states and aided by shortwave brings trailing quasi-
stnry weak surface trough to near coast or into extreme Nrn Gulf
of Mex. Weak surface wave appears to possibly develop at tail of
front slowing it down. With deep layer WSW flow will go with
50-20% SW-NE pop gradient which overlays well with MAV and local
confidence tool. Confidence tool hints at isold TSRA wrn waters
but for now will exclude to match our neighbors. Under light
winds, SREF, NAM and other guidance all show ample fog along
boundary. Temperatures will likely be held down somewhat by
extensive cloud cover, keeping highs in the upper 40s to around 50
for most areas.
These unsettled conditions will linger over the water into
Wednesday as the boundary is expected to move very little.
Without significant forcing, the stalled front may provide just
enough lift for 10-20% N-S showers over land, 30% over water. The
boundary should dissipate by Wed night as a large surface high
builds Ewd across Ern states leaving a fairly strong ridge over SE
region into Wed night. Then another rain event develops. Next
shortwave a little stronger and moves NE off TX/LA coast Ewd in
near zonal flow beginning on Wed. As a result, next surface low
develops over TX and moves thru SE region with trailing front
elongating Gulf Coast Thurs thru late Thurs night. However, models
strongly disagree on timing and intensity of system. ECMWF and NAM
quicker and with higher QPF than GFS in moving low solutions are
closer than 24hrs ago. Forecast a blend of ECMWF and confidence
tool. In either case, isentropic lift induced rain commences Wed
night west half of CFWA spreading SEWD on Thurs before exiting
shortwave lifts frontal trough northward and surface moisture E/NE
of local area by early Fri with low to outer banks of NC.
Will go with 40-20% W-E pops Wed night and 60-20% NW-SE gradient on
Thurs. Gradual warming trend. Min/Max temps are Wed Night 50 to 55
degrees and on Wed and Thurs 70 to 75 degrees.
&&
.LONG TERM [Thursday Night through Monday]...
As the extended period begins, the upper flow is forecast to be
largely zonal. However, a shortwave within this flow will be
pushing through Texas, with southwesterly flow overrunning the
stalled frontal boundary along the northern Gulf coast. Isentropic
lift is forecast to intensity along this boundary on Thursday,
allowing for a broad area of showers to push north into the
forecast area. At this time, it appears the instability will not
be sufficient for thunder, as the sfc boundary remain very close
to the coast.
By Friday, the shortwave will push off to the east. However, the
sfc front is expected to remain stationary or push just south of
the region. This may allow for a few showers even during the day
on Thursday.
By Saturday, high pressure will nose down the eastern seaboard
and push the boundary farther south of the area. This should keep
the region dry through the weekend. With the zonal flow aloft and
no source of cold air, temperatures are expected to remain above
normal through the end of the week.
&&
.AVIATION [through 06z Wednesday]...
In the early morning hours, a mid-level cloud deck was spreading
over much of the region, with CIGS generally between 5000 and 15000
feet AGL. The outlook is for VFR conditions to generally prevail for
much of the daytime hours as rain begins to develop east towards our
area. The exception will be at ECP where marginal MVFR CIGS appear
possible through the day. In heavier rain showers, it`s possible
that brief reductions in visibility into the MVFR range could occur.
There will be a better chance of low stratus or fog after sunset.
For now, we have indicated an MVFR forecast at all terminals, but
IFR is not out of the question.
&&
.MARINE...
A weak surface trough will settle along the northern Gulf Coast
thru early Wed. This will keep winds and seas mostly low and
onshore. By Thursday, a stronger storm system will approach from
the west and increase winds to near cautionary levels. Light to
moderate offshore flow will return on Friday before becoming
easterly into the weekend.
&&
.FIRE WEATHER...
Increased moisture and rain chances are expected for much of the
rest of the work week. Therefore, red flag conditions are not
expected over any of the area.
&&
.HYDROLOGY...
Despite increased rain chances this week, rainfall totals are
expected to remain low, with minimal impact on area rivers and
streams.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 63 53 71 55 73 / 70 40 20 30 50
Panama City 64 56 69 57 69 / 90 50 20 40 60
Dothan 63 49 73 55 70 / 50 40 10 30 60
Albany 64 48 73 53 70 / 30 30 10 20 60
Valdosta 69 52 71 55 74 / 30 30 20 20 40
Cross City 71 51 74 53 76 / 20 30 30 20 20
Apalachicola 65 56 68 57 68 / 80 40 20 40 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Block
LONG TERM...Camp
AVIATION...Lamers
MARINE...Block
FIRE WEATHER...Lamers
HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1154 PM CST MON FEB 4 2013
.UPDATE...
HAVE SENT GRID/ZFP UPDATE TO BUMP UP POPS NEAR/NORTH OF HWY
20 CORRIDOR BASED ON RADAR TRENDS AND SOME OF RECENT RAP MODEL
GUIDANCE. LOOKS LIKE QUICK HITTING WARM ADVECTION WING BAND
OF SNOW TO SWEEP DOWN NEAR HWY 20 CORRIDOR BETWEEN 09Z-12Z
PRODUCING QUICK DUSTING TO COUPLE TENTHS OF AN INCH OF ACCUM.
&&
.PREV DISCUSSION... /ISSUED 1139 PM CST MON FEB 4 2013/
AVIATION...
CLIPPER TYPE STORM SYSTEM WILL PASS JUST NORTHEAST OF THE
TERMINALS ON TUE. FAST MOVING BAND OF WARM ADVECTION
SNOW INTO FAR NORTHERN IA WILL SLIDE E/SE OVERNIGHT AND
MAY IMPACT KDBQ TERMINAL ROUGHLY 09Z-11Z WITH BRIEF SHOT
OF 2-5SM VSBYS WITH CIGS 1500-2500 FT AGL BEFORE LIFTING E
BY 12Z. ELSEWHERE... EXPECT VFR CONDITIONS INTO TUE AM IN
WARM SECTOR OF STORM WITH WINDS BECOMING GUSTY FROM THE
SOUTHWEST. POTENTIAL FOR ANOTHER BATCH OF SNOW AND BRIEF
PERIOD OF REDUCED VSBYS TO BRUSH MAINLY KDBQ TERMINAL TOWARD
MIDDAY INTO EARLY AFTERNOON WITH SYSTEM PASSING NEARBY.
OTHERWISE...ANTICIPATE LOW CLOUDS WITH MVFR CIGS TO DROP DOWN
ACROSS AREAS ESPECIALLY NEAR/NORTH OF I-80 BY TUE AFTERNOON
INTO EVENING WITH WINDS VEERING DURING THIS TIME TO W/NW AT
10-15 KTS AND GUSTY AT TIMES UNTIL SUNSET.
PREV DISCUSSION... /ISSUED 315 PM CST MON FEB 4 2013/
SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING RIDGE POISED JUST UPSTREAM WITH
AXIS LOCATED FROM NORTH OF THE MN ARROWHEAD...TO DOWN ACRS NORTH
CENTRAL KS. LLVL CLOUDS/STRATOCU HAVE REALLY DECAYED ALONG AND NORTH
OF I80 IN AFTERNOON SUBSIDENCE BEHIND PASSING UPPER LEVEL WAVE ACRS
CENTRAL IL. SFC CYCLOGENESIS CONTINUING NORTHWEST OF ND...WITH SFC
PRESSURE FALLS INCREASING DOWN THE EASTERN DAKOTAS. ELONGATED CLIPPER
TYPE WAVE NOTED ACRS WEST CENTRAL ALBERTA ON WATER VAPOR IMAGERY
LOOP.
SHORT TERM...TONIGHT AND TUESDAY...
TONIGHT...CHALLENGING TEMP FCST TONIGHT WITH RESPECT TO CLEARING
SKIES OVER SNOW COVER AND DECREASING WINDS WITH ARRIVAL OF THE SFC
RIDGE THIS EVENING. EXPECT A QUICK DROP OFF AFTER SUNSET IN AREAS
THAT ARE MAINLY CLEAR OR JUST GETTING SOME HIGHER LEVEL CLOUDS
STARTING TO SPILL IN FROM THE WEST AHEAD OF THE CLIPPER SYSTEM.
ONGOING NORTHERLY BOUNDARY LAYER FETCH ADVECTING LOWER SFC DPTS AND
SETTING THE STAGE FOR A CHILLY NIGHT DOWN IN THE SINGLE DIGITS IN
AREAS OF DEEPER SNOWPACK AND SOME DURATION OF CLEAR TO MOSTLY CLEAR
SKIES. BUT HOW LONG THE SKIES REMAIN MAINLY CLOUDY IS AT QUESTION...
AGAIN WITH THE MID AND HIGH LEVEL CLOUDS ACRS THE EASTERN PLAINS
STREAMING THIS WAY. WILL PLAY THE COOLER SIDE OF GUIDANCE OR EVEN
UNDERCUT THEM ACRS THE NORTHEASTERN HALF OF THE FCST AREA EXPECTING A
QUICK DIURNAL DROP...BUT MAY BE GOING TOO COLD IN THE NORTHWEST IF
THE UPSTREAM CLOUDS KEEP THERE CURRENT PACE AND THICKENING TRENDS.
CLOUDS MOVING/DECAYING OUT OF THE SOUTHERN CWA ALSO A CHALLENGE AND
LOOK LIKE THEY WILL CONTINUE TO PUSH SOUTHWARD THROUGH EARLY
EVENING...BUT AGAIN UPSTREAM CLOUDS INCREASING ACRS CENTRAL IA ON
TARGET TO FLOW BACK ACRS THE AREAS SOON AFTER. MILDER LOWS IN THE
SOUTH REMAINING IN THE TEENS. AS THE SFC LOW/REFLECTION OF INCOMING
CLIPPER CONTINUES TO DEVELOP AND MIGRATE ACRS CENTRAL MN ALONG
TIGHTER LLVL BAROCLINIC RIBBON BY 12Z TUE...INCREASING SOUTH TO
SOUTHWESTERLY SFC FLOW SOUTHEAST OF IT TO PRODUCE NON-DIURNAL TEMP
TRENDS FROM WEST TO EAST AFTER MIDNIGHT. LOW TO MID LEVEL SATURATION
LOOK MEAGER...BUT ENOUGH FOR ASSOCIATED LOW TO MID LEVEL WARM AIR
ADVECTION/CONVERGENT WINDS TO PRODUCE SOME LIGHT SNOW AND FLURRIES
ACRS THE NORTHERN THIRD TO QUARTER OF THE DVN CWA FROM MIDNIGHT INTO
SUNRISE. DUSTING POSSIBLE ALONG HWY 20 BY SUNRISE.
TUESDAY...WILL UTILIZE THE LATEST SREF GUIDANCE FOR TUE AS IT
APPEARS TO BE A DECENT GENERAL SOLUTION. IT SUGGESTS THE SFC LOW TO
CONTINUE TO PROPAGATE EAST-SOUTHEASTWARD TO NORTHEAST OF THE MADISON
WI AREA BY 18Z TUE...THEN OFF TO LOWER MI BY LATE TUE AFTERNOON.
OCCASIONAL LIGHT SNOW AND FLURRIES TO CONTINUE TO SPREAD SOUTH AND
EAST AS UPPER LEVEL FORCING DRAWS CLOSER...BUT STILL AFR ENOUGH FOR
ANY LIGHT ACCUMULATION TO REMAIN ACRS THE FAR NORTHERN/NORTHEASTERN
CWA. TAKING INTO ACCOUNT THE LATEST ACCEPTED EXTENT OF FORCING...
SATURATION AND LSR/S OF 13:1 TO 15:1...AREAS FROM JUST NORTHWEST OF
DBQ...TO SOUTH OF FREEPORT IL TO GET ONLY AROUND A HALF INCH OR SO.
AREAS 20 MILES TO THE SOUTH OF THAT LINE JUST A DUSTING...AND ONLY
FLURRIES FROM THERE DOWN TO I80. INCREASING SOUTHWESTERLY WARM DRAW
SOUTH OF THE CLIPPER TO BOOST TUE HIGH TEMPS TO AROUND 30 NORTH OF
I80...TO THE MID AND UPPER 30S IN THE SOUTHERN CWA. A 40 POSSIBLE
AROUND THE MACOMB AREA AND OTHER LESS SNOW COVERED AREAS OF THE
SOUTHEASTERN CWA. FLURRIES AND LIGHT SNOW TO START TO MIGRATE OUT OF
THE NORTHEASTERN CWA AS TUE AFTERNOON PROGRESSES. ..12..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
FORECAST FOCUS ON MIXED PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY
AND SIGNIFICANT STORM SYSTEM ARRIVING BY SUNDAY AND MONDAY. ECMWF
HAS BEEN MOST CONSISTENT IN THE LONG TERM AND HAVE LEANED HEAVILY ON
THIS MODEL.
TUESDAY NIGHT AND WEDNESDAY...HIGH PRESSURE WILL BE OVER THE DVN CWA
PROVIDING CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WINDS TUESDAY
NIGHT. THIS SHOULD ALLOW FOR DECENT RADIATIONAL COOLING ESPECIALLY
IN OUR NORTHERN CWA WHERE SNOW DEPTHS ARE CURRENTLY 6 TO 8 INCHES.
MINIMUM TEMPERATURES SHOULD DROP INTO THE SINGLE DIGITS NORTH TO
TEENS TO NEAR 20 SOUTH. THE HIGH SHIFTS TO THE OHIO VALLEY LATER
WEDNESDAY RETURNING SOUTH WINDS AS WARM AIR ADVECTION KICKS IN. MID
AND HIGH LEVEL CLOUDS SHOULD BE ON THE INCREASE FROM WEST TO EAST
DURING THE DAY. MAXIMUM TEMPERATURES SHOULD RANGE FROM THE 20S FAR
NORTH TO THE LOWER 40S WHERE BARE GROUND EXISTS.
WEDNESDAY NIGHT AND THURSDAY...ZONAL FLOW BECOMES ESTABLISHED ACROSS
THE MIDWEST WITH A LONG WAVE TROUGH MOVING ACROSS THE REGION.
INITIALLY THE LOW LEVELS WILL BE DRY BUT WITH CONTINUED WARM AIR
ADVECTION AND INCREASING MOISTURE THIS SHOULD ALLOW FOR
PRECIPITATION TO DEVELOP WEDNESDAY EVENING IN EASTERN IA. THE
PRECIPITATION WILL THEN SPREAD OVER ALL THE CWA WEDNESDAY NIGHT AND
CONTINUE INTO THURSDAY MORNING. WITH EVAPORATIVE COOLING AND WET
BULBS NEAR TO BELOW FREEZING THERE IS THE POTENTIAL FOR A MIX OF
FREEZING RAIN...SLEET AND SNOW IN OUR NORTH. LOOKS TO BE ALL RAIN IN
OUR SOUTHERN CWA WEDNESDAY NIGHT. A BIT COLDER AIR ALOFT ON THURSDAY
SHOULD ALLOW FOR A MIX OF RAIN AND SNOW OVER THE ENTIRE CWA BEFORE
ENDING FROM WEST TO EAST. WILL HAVE LIKELY POPS FOR THIS EVENT WITH
PRECIPITATION AMOUNTS .10 TO .25.
SUNDAY THROUGH MONDAY...ECMWF HAS BEEN THE MOST CONSISTENT IN
SHOWING A STRONG STORM SYSTEM IMPACTING THE MIDWEST. HOWEVER...THE
12Z RUN HAS SLOWED THIS SYSTEM SOMEWHAT WITH THE RAIN NOT ARRIVING
UNTIL EITHER LATE SATURDAY NIGHT OR SUNDAY MORNING. WATER VAPOR
LOOPS CURRENTLY SHOW A POTENT WAVE ABOUT 1100 MILES WEST OF SEATTLE.
WITH BLOCKING TO THE NORTH THE WAVE IS FORCED TO DIVE INTO THE
WESTERN UNITED STATES CARVING OUT A DEEP TROUGH BY THE WEEKEND. THE
12Z RUN IS SHOWING THE SURFACE LOW TRACKING ACROSS NORTHEAST IA
WHICH IS A NORTHWARD SHIFT FROM THE 00Z RUN. THIS SYSTEM WOULD GIVE
THE ENTIRE CWA A WIDESPREAD MODERATE TO POTENTIALLY HEAVY RAIN EVENT
WITH AMOUNTS AT LEAST AN INCH. THE UPPER LOW FORMS A NICE CLOSED
CIRCULATION WITH A DEFORMATION BAND OF ACCUMULATING SNOW COMING
ACROSS OUR NORTHERN CWA SUNDAY NIGHT INTO MONDAY AS COLDER AIR WRAPS
AROUND THE SYSTEM. WAY TOO EARLY FOR SPECIFICS ON SNOW AMOUNTS BUT
THE MODELS SHOULD HAVE A BETTER HANDLE ON THE TRACK WHEN THE UPPER
AIR NETWORK BEGINS SAMPLING THE WAVE LATER THIS WEEK.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
923 PM CST WED FEB 6 2013
.UPDATE...
CONVECTION HAS DEVELOPED ACROSS NORTHEAST KANSAS AT MID-EVENING
WITH THE LATEST NAM AND RUC DEVELOPING IT SOUTHWEST ACROSS CENTRAL
KANSAS TOWARD MIDNIGHT. THIS IS HANDLED FAIRLY WELL IN CURRENT
FORECAST WITH ONLY SLIGHT TWEAKS INTO THE OVERNIGHT HOURS. PATCHY
FOG AND DRIZZLE WILL CONTINUE AHEAD OF THE FRONT AS A PRECURSOR
TO THE CONVECTION...THOUGH DO NOT EXPECT THE RESTRICTIONS TO BE
LOW ENOUGH AND WIDESPREAD FOR A DENSE FOG HEADLINE AT THE MOMENT.
ELEVATED CAPE VALUES AROUND 500 J/KG AND MODEST SHEAR VALUES MAY
SUPPORT A FEW STRONG STORMS WITH SMALL HAIL AND HAVE MADE A SLIGHT
ADJUSTMENT TO THE RISK AREA OVERNIGHT.
KED
&&
.PREV DISCUSSION... /ISSUED 545 PM CST WED FEB 6 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR/IFR CIGS AND VSBYS ARE EXPECTED TO EXPAND ACROSS MUCH OF THE
AREA TONIGHT AS A COLD FRONT SLIDES EAST ACROSS CENTRAL KANSAS.
FOG AND PATCHY DRIZZLE THIS EVENING WILL BE REPLACED BY SCATTERED
TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS LATE IN THE NIGHT.
THIS ACTIVITY IS EXPECTED TO TRANSITION EAST WITH THE COLD FRONT
ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS EARLY THURSDAY MORNING.
GUSTY NORTH WINDS WILL BRING IN DRIER AIR DURING THE DAYLIGHT
HOURS ON THURSDAY WITH CONDITIONS IMPROVING FOR THE LATTER PORTION
OF THE FORECAST VALID PERIOD.
KED
PREV DISCUSSION... /ISSUED 338 PM CST WED FEB 6 2013/
DISCUSSION...
TONIGHT-THU:
MOISTURE WILL CONTINUE TO INCREASE AHEAD OF FRONT. GOOD CHANCE OF
PATCHY TO AREAS OF DRIZZLE/LIGHT SHOWERS AND FOG ACROSS SOUTH
CENTRAL/SOUTHEAST KS AS LOW LEVEL MOISTURE INCREASES AHEAD OF
FRONT. PRECIPITATION SHOULD BREAK OUT IN CENTRAL KS AHEAD OF FRONT
THIS EVENING...WITH CHANCES INCREASE TOWARDS MIDNIGHT. TOUGH CALL
ON BACK EDGE OF PRECIPITATION AT 1200 UTC...BUT LIKELY IN THE
VICINITY OF KHUT/KICT. PRECIPITATION WILL LINGER EAST OF TURNPIKE
THROUGH NOON AND EXTREME SOUTHEAST KS PAST 1800 UTC. TEMPERATURES
WILL BE HELD UP OVERNIGHT AT MOST LOCATIONS WITH SURFACE DEWPOINTS
CLIMBING INTO THE 50S. GUSTY NORTHWEST WINDS ANTICIPATED ON THU IN
WAKE OF FRONT WITH MOSTLY CLEAR SKIES AND GOOD MIXING.
FRI-SUN:
QUIET WEATHER ANTICIPATED ON FRI. TEMPERATURES STILL A BIT TRICKY
AND DEPENDENT ON MIXING HEIGHT WITH FAIRLY WARM AIR ALOFT AND AT
LEAST SOME COLDER AIR NEAR SURFACE. BASED ON RECENT VERIFICATION...
HAVE LEANED A BIT WARMER. BY FRIDAY NIGHT RETURN FLOW WILL BE
UNDERWAY WITH LOW LEVEL MOISTURE ON THE INCREASE. SOME WARM AIR
ADVECTION PRECIPITATION IS EXPECTED TO BREAK OUT SAT MORNING...
WITH CHANCES INCREASE SAT NIGHT/SUN AS SURFACE FRONT APPROACHES.
GFS HAS BEEN UNDERESTIMATING INSTABILITY AND GIVEN SYNOPTIC SET UP
WITH DIFFLUENT SOUTHWEST FLOW ALOFT AND NICE DRYLINE...BELIEVE
THERE IS A DECENT CHANCE OF STORMS DURING THE NIGHT. EVEN WITH
LESS THAN OPTIMAL TIMING OF THE DRYLINE...THE VERY STRONG DEEP
LAYER SHEAR MAY ALLOW SOME STORMS TO GET A BIT FRISKY.
PRECIPITATION CHANCES WILL END ABRUPTLY AS DRY SLOT WORKS ACROSS
THE AREA EARLY ON SUN. TRACK OF SURFACE LOW SHOULD KEEP WRAP
AROUND PRECIPITATION JUST NORTH OF FORECAST AREA.
MON-WED:
RELATIVELY QUIET AND SEASONAL WEATHER ANTICIPATED MON...BUT
DIFFERENCES IN ECMWF ARE EVIDENT ON TUE-WED. WHILE BOTH MORE OR
LESS SHOW SHORTWAVE ENERGY INDUCING SURFACE WAVE ON FRONT TO THE
SOUTH...GFS HAS SLOPPED PRECIPITATION A LOT FURTHER NORTH/NORTHWEST
THAN THE ECMWF. INITIALIZATION GRIDS REFLECTED THIS WITH LOW POPS
ACR SOUTHERN/SOUTHEAST KS. AT THIS TIME...BELIEVE CHANCES ARE SLIM
AND HAVE NIXED ACROSS SOUTH CENTRAL KS..BUT KEPT IN FAR SOUTHEAST
FOR CONSISTENCY. -HOWERTON
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS THE IFR/MVFR CONDITIONS
TODAY/TONIGHT AND THUNDERSTORMS POSSIBLE TONIGHT.
LOW STRATUS HAS DEVELOPED ACROSS SOUTH CENTRAL AND NORTH TO
CENTRAL KANSAS AS THE WARM FRONT HAS STREAMED NORTHWARD AND HIGHER
DEWPOINTS ARE INTERACTING WITH THE COOLER TEMPERATURES. EXPECT
MVFR TO HIGH IFR STRATUS TO CONTINUE THROUGH THE NEXT 12-18 HOURS
AT MANY SITES. THE FRONT WILL MOVE THROUGH AND THE UPPER PATTERN
WILL HELP TO FIRE OFF THUNDERSTORMS BEGINNING OVERNIGHT. THINK THE
SITES WITH THE BEST CHANCE FOR THUNDERSTORMS WILL BE
KSLN/KHUT/KICT AND KCNU. THE RAIN WILL MOVE OUT AS THE UPPER WAVE
ROTATES EASTWARD...ENDING THINGS FROM WEST TO EAST THURSDAY
MORNING.
WINDS WILL BECOME NORTHERLY BEHIND THE FRONT AND BE BREEZY...BUT
CEILINGS WILL LIFT AS DRIER AIR MOVES IN.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 51 54 30 57 / 80 60 0 0
HUTCHINSON 47 54 29 55 / 80 30 0 0
NEWTON 48 53 29 56 / 80 50 0 0
ELDORADO 50 53 28 56 / 80 80 0 0
WINFIELD-KWLD 51 55 29 57 / 30 80 0 0
RUSSELL 43 53 27 55 / 40 10 0 0
GREAT BEND 44 53 27 55 / 80 10 0 0
SALINA 46 54 27 57 / 80 10 0 0
MCPHERSON 46 53 28 56 / 80 20 0 0
COFFEYVILLE 48 56 30 58 / 10 80 0 0
CHANUTE 47 53 28 55 / 20 80 0 0
IOLA 47 52 28 54 / 30 80 0 0
PARSONS-KPPF 47 55 29 57 / 20 80 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
548 PM CST WED FEB 6 2013
...UPDATED FOR CURRENT TRENDS AND EXPECTED OVERNIGHT FOG...
.SYNOPSIS...
ISSUED AT 911 AM CST WED FEB 6 2013
THE 06.12Z 250 RAOB SYNOPTIC MAP SHOWED ANTICYCLONIC JET FLOW ACROSS
THE CENTRAL US AND EXTENDING INTO PORTIONS OF THE UPPER MIDWEST. A JET
STREAK OF AROUND 125 KT WAS OBSERVED ACROSS WISCONSIN. FAIRLY LIGHT
UPPER LEVEL FLOW WAS OBSERVED ACROSS SOUTHERN KANSAS WITH ONLY 30 KT
AT KDDC. AT 500 HPA, A LARGE CYCLONE WAS LOCATED ACROSS THE NORTHEAST
PACIFIC. A FEW SHORTWAVES WERE NOTED ACROSS THE GREAT BASIN AND TEXAS.
AT 700 HPA, TEMPERATURES WERE AT ZERO CENTIGRADE ACROSS THE TEXAS PANHANDLE
AND SOUTHWEST KANSAS...INDICATING A WAA PATTERN STILL IN PLACE. THE
WARM PLUME AT 850 HPA WAS VERY EVIDENT ACROSS THE CENTRAL PLAINS WITH
VALUES IN THE 8 TO 12 DEG C RANGE. AT THE SFC, A WARM FRONT WAS LOCATED
ALONG WITH THE KANSAS/OKLAHOMA STATE LINE WITH HIGHER DEWPOINTS ADVECTING
IN FROM OKLAHOMA.
&&
.UPDATE...
ISSUED AT 545 PM CST WED FEB 6 2013
THE LATEST HIGH RESOLUTION NAM WRF CORES AND THE RAPID REFRESH ARE
STRONGLY SUGGESTING THE RAPID ONSET OF DENSE FOG DEVELOPMENT THIS
EVENING. THE MODELS ARE PROBABLY DOING A BETTER JOB THAN THE LOCAL
GFS MOS AT THIS TIME, WHICH APPEARS TOO FOCUSED ON TYPICAL DIURNAL
TRENDS. WITH LOW 50`S DEW POINTS INCREASING THIS EVENING, AND
BACKING SURFACE WINDS CREATING WEAK UPSLOPE AHEAD OF AN ADVANCING
COLD FRONT FROM NORTHWEST KANSAS, FOG COULD START TO DEVELOP FROM
DIGHTON TO GARDEN CITY BY MID EVENING. A DENSE FOG ADVISORY WAS
HOISTED FROM GENERALLY THE HIGHWAY 83 CORRIDOR EASTWARD FROM 4 TO 12
UTC THURSDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 236 PM CST WED FEB 6 2013
TONIGHT:
SEVERAL SENSIBLE WEATHER IMPACTS EXPECTED TONIGHT INTO TOMORROW MORNING.
FIRST IS FOG. HRRR IS VERY AGGRESSIVE IN DEVELOPING LOW VISIBILITIES
AFTER 00Z TONIGHT. THE NAM AND ARW-WRF IS NOT AS AGGRESSIVE WITH FOG.
DUE TO THE WARM AIR ADVECTION PATTERN THAT IS CURRENTLY TAKING PLACE
AND THE HIGHER DEWPOINTS ADVECTING IN ACROSS THE REGION...WILL GO WITH
PATCHY FOG TONIGHT ALONG AND EAST OF HIGHWAY 283 WITH AREAS OF FOG
ALONG SOUTH CENTRAL KANSAS WHERE DEWPOINTS ARE HIGHER. THE NEXT CONCERN
IS CONVECTION. THE BEST CHANCE FOR OVERNIGHT THUNDERSTORMS IS GENERALLY
ALONG AND EAST OF HIGHWAY 183. HERE WARM AIR ADVECTION...ISENTROPIC
LIFT ALONG THE 295 KELVIN THETA SURFACE... AND INCREASING 850-650 HPA
FRONTOGENESIS SHOULD INITIATE CONVECTIVE ACTIVITY AFTER 03Z TONIGHT.
ALL THE MESOSCALE MODELS SUGGESTS THIS AS WELL AS THE GFS AND ECMWF.
SEVERE THUNDERSTORMS ARE NOT EXPECTED DUE TO WEAK THERMODYNAMICS AND
WEAK KINEMATICS. CONVECTION SHOULD BE CLEAR OF THE REGION BY DAWN.
A DENSE FOG ADVISORY COULD BE NEEDED FOR TOMORROW MORNING, BUT DO NOT
HAVE ENOUGH CONFIDENCE TO ISSUE ONE THIS EARLY.
TOMORROW:
TOMORROW MORNING WILL BE BREEZY AS THERE WILL BE A TIGHT PRESSURE GRADIENT
ACROSS THE REGION ALONG WITH 45 KT 850 HPA WINDS PARTIALLY MIXING DOWN.
NOT EXPECTING WIND ADVISORY LEVELS AT THIS TIME. OTHER THAN SOME POSSIBLE
LINGERING FOG, TOMORROW WILL BE FAIRLY QUIET WITH CLEARING SKIES. HIGHS
SHOULD BE IN THE 50S DEG F. WINDS SHOULD ABATE AS THE DAY WEARS ON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 PM CST WED FEB 6 2013
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
MOVING EASTWARD ACROSS THE CENTRAL PLAINS FRIDAY RESULTING IN DRY
CONDITIONS ACROSS WESTERN KANSAS THROUGH FRIDAY NIGHT. MEANWHILE,
A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE IS EXPECTED TO DIG
SOUTHEAST INTO THE GREAT BASIN REGION FRIDAY, THEN TURN EASTWARD
MOVING INTO THE CENTRAL AND SOUTHERN ROCKIES SATURDAY BRINGING THE
POSSIBILITY FOR SHOWERS AND THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS AS EARLY AS SATURDAY AFTERNOON. A RETURN FLOW WILL SET UP
EARLY FRIDAY DRAWING GULF MOISTURE NORTHWARD INTO MUCH OF KANSAS
WITH H85 DEWPOINTS CLIMBING JUST ABOVE 0C. ADDITIONALLY, SURFACE
LOW PRESSURE IN EASTERN COLORADO WILL STRENGTHEN THROUGHOUT THE
DAY WITH A SHARPENING DRYLINE EXTENDING SOUTHWARD GENERALLY INTO
THE TEXAS PANHANDLE. DYNAMIC SUPPORT ALOFT WILL BECOME MORE
FAVORABLE AS WELL WITH THE GFS AND ECMWF SHOWING A STRONG H5 VORT
MAX LIFTING NORTHEAST OUT OF THE TROUGH AXIS AND ACROSS THE
WESTERN HIGH PLAINS SATURDAY NIGHT. A +100KT UPPER LEVEL JET WILL
ALSO BE STREAMING EAST-NORTHEAST ACROSS WEST TEXAS AND THE TEXAS
PANHANDLE INTO THE PLAINS OF WESTERN OKLAHOMA AND SOUTHERN KANSAS
LATE SATURDAY. AS A RESULT, SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP ACROSS THE SOUTH PLAINS SATURDAY AFTERNOON AND EVENING,
LIFTING NORTHEASTWARD INTO CENTRAL KANSAS WITH CHANCES FOR THE
PRECIP DWINDLING TOWARD THE WEST. GFS AND ECMWF MODEL SOUNDINGS
INDICATE A REAL LACK OF INSTABILITY LIMITING SEVERE POTENTIAL.
ANY PRECIP WILL LIKELY COME TO AN END BY MID DAY SUNDAY AS THE
UPPER LEVEL TROUGH BEGINS TO LIFT NORTHEAST INTO THE UPPER
MIDWEST.
TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL FRIDAY EVEN AS SURFACE
HIGH PRESSURE MOVES FROM THE NORTHERN PLAINS SOUTHEAST INTO THE
UPPER MIDWEST. THIS WILL TURN WINDS SOUTH TO SOUTHEASTERLY ACROSS
WESTERN KANSAS THROUGHOUT MUCH OF THE DAY. HOWEVER, THIS WILL DO
LITTLE TO ERODE THE COOLER AIR MASS THAT IS PROJECTED TO SINK
SOUTH INTO WESTERN KANSAS BEHIND A PASSING COLD FRONT THURSDAY.
THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING FROM JUST
ABOVE 0C ACROSS CENTRAL KANSAS TO JUST ABOVE 5C ALONG THE COLORADO
BORDER. LOOK FOR HIGHS WELL UP INTO THE 50S(F) FRIDAY AFTERNOON.
SIMILAR HIGHS ARE LIKELY SATURDAY AS SURFACE LOW PRESSURE
STRENGTHENS ACROSS EASTERN COLORADO KEEPING SOUTHERLY WINDS IN
PLACE ACROSS WESTERN KANSAS. A COLD FRONT PUSHING THROUGH WESTERN
KANSAS SUNDAY WILL ALLOW COLDER AIR TO SURGE SOUTHWARD INTO
WESTERN KANSAS RESULTING IN LOWER HIGH TEMPERATURES. OVERALL,
TEMPERATURES ARE LIKELY TO REMAIN BELOW NORMAL THROUGH MID WEEK AS
A SECONDARY UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTERMOUNTAIN
WEST AND MOVES INTO THE WESTERN HIGH PLAINS DRAWING MORE COLDER
DOWN INTO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 531 PM CST WED FEB 6 2013
THE MAJOR IMPACT TO AVIATION WILL BE DENSE FOG DEVELOPMENT LATE
THIS EVENING AND LASTING THROUGH THE OVERNIGHT. INCREASING LOW
LEVEL MOISTURE AHEAD OF A SURFACE COLD FRONT WILL PROVIDE THE
CONDITIONS FOR ADVECTION FOG ACROSS MUCH OF CENTRAL ANS SOUTHWEST
KANSAS BEGINNING AS EARLY AS 03 UTC. THE LATEST MESOSCALE MODELS
INCLUDING THE VARIOUS NAM ARW CORES AND THE RAPID REFRESH ARE ALL
STRONGLY SUGGESTING DENSE FOG DEVELOPMENT. IT IS BELIEVED THE LOCAL
GFS MOS (LAMP) IS TOO FOCUSED ON NORMAL DIURNAL TRENDS AND LIKELY
INCORRECT. A 700 MB WAVE WILL HELP SET OFF SHOWERS AND ISOLATED
THUNDERSTORM ACROSS CENTRAL KANSAS AS WELL, PROBABLY JUST EAST OF
HAYS AND DODGE CITY BETWEEN MID NIGHT AND 10Z. AT THIS TIME, TEMPO
1/4SM CONDITIONS WILL BE CARRIE UNTIL SUCH CONFIDENCE THAT
PREVAILING CONDITIONS CAN BE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 54 27 56 / 10 0 0 0
GCK 36 53 27 56 / 0 0 0 0
EHA 34 51 27 57 / 0 0 0 0
LBL 37 53 27 57 / 0 0 0 0
HYS 39 53 25 55 / 40 0 0 0
P28 48 55 30 56 / 80 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 6 AM CST THURSDAY
FOR KSZ030-031-043>046-063>066-076>081-086>090.
&&
$$
UPDATE...RUSSELL
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...JJOHNSON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
533 PM CST WED FEB 6 2013
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 911 AM CST WED FEB 6 2013
THE 06.12Z 250 RAOB SYNOPTIC MAP SHOWED ANTICYCLONIC JET FLOW ACROSS
THE CENTRAL US AND EXTENDING INTO PORTIONS OF THE UPPER MIDWEST. A JET
STREAK OF AROUND 125 KT WAS OBSERVED ACROSS WISCONSIN. FAIRLY LIGHT
UPPER LEVEL FLOW WAS OBSERVED ACROSS SOUTHERN KANSAS WITH ONLY 30 KT
AT KDDC. AT 500 HPA, A LARGE CYCLONE WAS LOCATED ACROSS THE NORTHEAST
PACIFIC. A FEW SHORTWAVES WERE NOTED ACROSS THE GREAT BASIN AND TEXAS.
AT 700 HPA, TEMPERATURES WERE AT ZERO CENTIGRADE ACROSS THE TEXAS PANHANDLE
AND SOUTHWEST KANSAS...INDICATING A WAA PATTERN STILL IN PLACE. THE
WARM PLUME AT 850 HPA WAS VERY EVIDENT ACROSS THE CENTRAL PLAINS WITH
VALUES IN THE 8 TO 12 DEG C RANGE. AT THE SFC, A WARM FRONT WAS LOCATED
ALONG WITH THE KANSAS/OKLAHOMA STATE LINE WITH HIGHER DEWPOINTS ADVECTING
IN FROM OKLAHOMA.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 236 PM CST WED FEB 6 2013
TONIGHT:
SEVERAL SENSIBLE WEATHER IMPACTS EXPECTED TONIGHT INTO TOMORROW MORNING.
FIRST IS FOG. HRRR IS VERY AGGRESSIVE IN DEVELOPING LOW VISIBILITIES
AFTER 00Z TONIGHT. THE NAM AND ARW-WRF IS NOT AS AGGRESSIVE WITH FOG.
DUE TO THE WARM AIR ADVECTION PATTERN THAT IS CURRENTLY TAKING PLACE
AND THE HIGHER DEWPOINTS ADVECTING IN ACROSS THE REGION...WILL GO WITH
PATCHY FOG TONIGHT ALONG AND EAST OF HIGHWAY 283 WITH AREAS OF FOG
ALONG SOUTH CENTRAL KANSAS WHERE DEWPOINTS ARE HIGHER. THE NEXT CONCERN
IS CONVECTION. THE BEST CHANCE FOR OVERNIGHT THUNDERSTORMS IS GENERALLY
ALONG AND EAST OF HIGHWAY 183. HERE WARM AIR ADVECTION...ISENTROPIC
LIFT ALONG THE 295 KELVIN THETA SURFACE... AND INCREASING 850-650 HPA
FRONTOGENESIS SHOULD INITIATE CONVECTIVE ACTIVITY AFTER 03Z TONIGHT.
ALL THE MESOSCALE MODELS SUGGESTS THIS AS WELL AS THE GFS AND ECMWF.
SEVERE THUNDERSTORMS ARE NOT EXPECTED DUE TO WEAK THERMODYNAMICS AND
WEAK KINEMATICS. CONVECTION SHOULD BE CLEAR OF THE REGION BY DAWN.
A DENSE FOG ADVISORY COULD BE NEEDED FOR TOMORROW MORNING, BUT DO NOT
HAVE ENOUGH CONFIDENCE TO ISSUE ONE THIS EARLY.
TOMORROW:
TOMORROW MORNING WILL BE BREEZY AS THERE WILL BE A TIGHT PRESSURE GRADIENT
ACROSS THE REGION ALONG WITH 45 KT 850 HPA WINDS PARTIALLY MIXING DOWN.
NOT EXPECTING WIND ADVISORY LEVELS AT THIS TIME. OTHER THAN SOME POSSIBLE
LINGERING FOG, TOMORROW WILL BE FAIRLY QUIET WITH CLEARING SKIES. HIGHS
SHOULD BE IN THE 50S DEG F. WINDS SHOULD ABATE AS THE DAY WEARS ON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 PM CST WED FEB 6 2013
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
MOVING EASTWARD ACROSS THE CENTRAL PLAINS FRIDAY RESULTING IN DRY
CONDITIONS ACROSS WESTERN KANSAS THROUGH FRIDAY NIGHT. MEANWHILE,
A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE IS EXPECTED TO DIG
SOUTHEAST INTO THE GREAT BASIN REGION FRIDAY, THEN TURN EASTWARD
MOVING INTO THE CENTRAL AND SOUTHERN ROCKIES SATURDAY BRINGING THE
POSSIBILITY FOR SHOWERS AND THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS AS EARLY AS SATURDAY AFTERNOON. A RETURN FLOW WILL SET UP
EARLY FRIDAY DRAWING GULF MOISTURE NORTHWARD INTO MUCH OF KANSAS
WITH H85 DEWPOINTS CLIMBING JUST ABOVE 0C. ADDITIONALLY, SURFACE
LOW PRESSURE IN EASTERN COLORADO WILL STRENGTHEN THROUGHOUT THE
DAY WITH A SHARPENING DRYLINE EXTENDING SOUTHWARD GENERALLY INTO
THE TEXAS PANHANDLE. DYNAMIC SUPPORT ALOFT WILL BECOME MORE
FAVORABLE AS WELL WITH THE GFS AND ECMWF SHOWING A STRONG H5 VORT
MAX LIFTING NORTHEAST OUT OF THE TROUGH AXIS AND ACROSS THE
WESTERN HIGH PLAINS SATURDAY NIGHT. A +100KT UPPER LEVEL JET WILL
ALSO BE STREAMING EAST-NORTHEAST ACROSS WEST TEXAS AND THE TEXAS
PANHANDLE INTO THE PLAINS OF WESTERN OKLAHOMA AND SOUTHERN KANSAS
LATE SATURDAY. AS A RESULT, SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP ACROSS THE SOUTH PLAINS SATURDAY AFTERNOON AND EVENING,
LIFTING NORTHEASTWARD INTO CENTRAL KANSAS WITH CHANCES FOR THE
PRECIP DWINDLING TOWARD THE WEST. GFS AND ECMWF MODEL SOUNDINGS
INDICATE A REAL LACK OF INSTABILITY LIMITING SEVERE POTENTIAL.
ANY PRECIP WILL LIKELY COME TO AN END BY MID DAY SUNDAY AS THE
UPPER LEVEL TROUGH BEGINS TO LIFT NORTHEAST INTO THE UPPER
MIDWEST.
TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL FRIDAY EVEN AS SURFACE
HIGH PRESSURE MOVES FROM THE NORTHERN PLAINS SOUTHEAST INTO THE
UPPER MIDWEST. THIS WILL TURN WINDS SOUTH TO SOUTHEASTERLY ACROSS
WESTERN KANSAS THROUGHOUT MUCH OF THE DAY. HOWEVER, THIS WILL DO
LITTLE TO ERODE THE COOLER AIR MASS THAT IS PROJECTED TO SINK
SOUTH INTO WESTERN KANSAS BEHIND A PASSING COLD FRONT THURSDAY.
THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING FROM JUST
ABOVE 0C ACROSS CENTRAL KANSAS TO JUST ABOVE 5C ALONG THE COLORADO
BORDER. LOOK FOR HIGHS WELL UP INTO THE 50S(F) FRIDAY AFTERNOON.
SIMILAR HIGHS ARE LIKELY SATURDAY AS SURFACE LOW PRESSURE
STRENGTHENS ACROSS EASTERN COLORADO KEEPING SOUTHERLY WINDS IN
PLACE ACROSS WESTERN KANSAS. A COLD FRONT PUSHING THROUGH WESTERN
KANSAS SUNDAY WILL ALLOW COLDER AIR TO SURGE SOUTHWARD INTO
WESTERN KANSAS RESULTING IN LOWER HIGH TEMPERATURES. OVERALL,
TEMPERATURES ARE LIKELY TO REMAIN BELOW NORMAL THROUGH MID WEEK AS
A SECONDARY UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTERMOUNTAIN
WEST AND MOVES INTO THE WESTERN HIGH PLAINS DRAWING MORE COLDER
DOWN INTO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 531 PM CST WED FEB 6 2013
THE MAJOR IMPACT TO AVIATION WILL BE DENSE FOG DEVELOPMENT LATE
THIS EVENING AND LASTING THROUGH THE OVERNIGHT. INCREASING LOW
LEVEL MOISTURE AHEAD OF A SURFACE COLD FRONT WILL PROVIDE THE
CONDITIONS FOR ADVECTION FOG ACROSS MUCH OF CENTRAL ANS SOUTHWEST
KANSAS BEGINNING AS EARLY AS 03 UTC. THE LATEST MESOSCALE MODELS
INCLUDING THE VARIOUS NAM ARW CORES AND THE RAPID REFRESH ARE ALL
STRONGLY SUGGESTING DENSE FOG DEVELOPMENT. IT IS BELIEVED THE LOCAL
GFS MOS (LAMP) IS TOO FOCUSED ON NORMAL DIURNAL TRENDS AND LIKELY
INCORRECT. A 700 MB WAVE WILL HELP SET OFF SHOWERS AND ISOLATED
THUNDERSTORM ACROSS CENTRAL KANSAS AS WELL, PROBABLY JUST EAST OF
HAYS AND DODGE CITY BETWEEN MID NIGHT AND 10Z. AT THIS TIME, TEMPO
1/4SM CONDITIONS WILL BE CARRIE UNTIL SUCH CONFIDENCE THAT
PREVAILING CONDITIONS CAN BE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 54 27 56 / 10 0 0 0
GCK 36 53 27 56 / 0 0 0 0
EHA 34 51 27 57 / 0 0 0 0
LBL 37 53 27 57 / 0 0 0 0
HYS 39 53 25 55 / 40 0 0 0
P28 48 55 30 56 / 80 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FROM 10 PM THIS EVENING TO 6 AM CST THURSDAY
FOR KSZ030-031-043>046-063>066-076>081-086>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...JJOHNSON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1148 PM MST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1243 PM MST MON FEB 4 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW NW FLOW STILL IN PLACE
FROM BRITISH COLUMBIA ACROSS THE CENTRAL HIGH PLAINS INTO THE
SOUTHERN MISSISSIPPI RIVER VALLEY. LEE TROUGH REMAINS IN PLACE OVER
EASTERN COLORADO WITH ANOTHER WEAK TROUGH AXIS OVER NW KANSAS.
OTHER THAN PASSING HIGH CLOUDS WITHIN NW FLOW TONIGHT...THERE IS
WILL BE VERY LITTLE CHANGE IN EXPECTED CONDITIONS TONIGHT VERSUS
THE LAST FEW NIGHTS...WITH LOWS GENERALLY IN 20S ACROSS THE AREA.
A SHORTWAVE RIDGE WILL BEGIN TO BUILD OVER THE INTER-MOUNTAIN
WEST BY MIDDAY TUESDAY WITHIN PROGRESSIVE FLOW. THERE MAY BE WEAK
FORCING WITHIN THE VICINITY OF THE CWA TUESDAY AFTERNOON AS A
H7-H5 VORT MAX PROGRESSES ACROSS NORTHERN EXTENT OF RIDGE IN
RESPONSE TO A DEEPENING SHORTWAVE TROUGH OVER THE NORTHERN
ROCKIES. HOWEVER...WITH DEEP DRY AIR MASS IN PLACE THIS SHOULD ONLY
RESULT IN INCREASING HIGH CLOUD COVER BY LATE TUESDAY AFTERNOON.
WITH ALL OF THIS IN MIND...I AM ANTICIPATING MILD/DRY CONDITIONS
AGAIN ON TUESDAY WITH HIGHS IN THE MID-UPPER 50S.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 1143 PM MST MON FEB 4 2013
MILD AND DRY CONDITIONS CONTINUE ON FRIDAY UNDER SHORTWAVE RIDGING
AHEAD OF APPROACHING SYSTEM. MODELS HAVE MADE NO IMPROVEMENT AND
STILL HAVE SIGNIFICANT DIFFERENCES. ECMWF BRINGS A CUT OFF LOW
OVER THE FORECAST AREA SATURDAY NIGHT/SUNDAY WITH WIND AND SNOW.
GFS IS MUCH WEAKER AND SLOWER AND WITH A MORE SOUTHERLY
TRACK...GENERALLY BRINGING LIGHT SNOW IN THE SUNDAY AND MONDAY
PERIOD. WITH NO REAL REASON TO FAVOR EITHER SOLUTION...WILL
CONTINUE TO CARRY SLIGHT TO CHANCE POPS IN THE SATURDAY THROUGH
MONDAY PERIODS. THE SYSTEM IS NOT ALL THAT COLD FOR
FEBRUARY...WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 932 PM MST MON FEB 4 2013
VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS AT KGLD AND
KMCK. LIGHT WEST WIND WILL SHIFT TO THE NORTH LATE TUESDAY MORNING
AT BOTH SITES AS A HIGH PRESSURE BUILDS IN BEHIND A TROUGH MOVING
EAST OF THE AREA. WIND WILL SHIFT SOUTH TUESDAY EVENING IN
RESPONSE TO A SURFACE TROUGH IN EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...032
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1132 PM CST MON FEB 4 2013
...UPDATE TO AVIATION...
.DISCUSSION...
LATEST SURFACE ANALYSIS HAD HIGH PRESSURE BUILDING INTO NORTHEAST
KANSAS AT 20Z. STRATUS HAS BEEN ERODING NORTH OF INTERSTATE 70 THIS
AFTERNOON AREAS SOUTH OF I-70 HAVE REMAINED CLEAR TODAY.
LATEST RAP 13 RELATIVE HUMIDITY PLOTS KEEP THE LOWER LAYERS
SATURATED THROUGH THE EVENING. DEPENDING ON HOW WELL THE LOWER
BOUNDARY LAYER MIXES OUT THIS AFTERNOON...STATUS MAY MOVE BACK SOUTH
OR REFORM AFTER SUNSET. WILL KEEP SOME CLOUDS NORTH OF I-70 THIS
EVENING WITH MOSTLY CLEAR SKIES IN THE SOUTH. LOWS TONIGHT WILL
RANGE FROM THE LOWER 20S IN THE FAR NORTHEAST TO THE MID 20S
ELSEWHERE IN NORTHEAST...NORTH CENTRAL AND EAST CENTRAL KANSAS.
THE SURFACE HIGH MOVES OFF TO THE EAST TONIGHT WITH RETURN FLOW
OCCURRING AFTER 06Z TUESDAY. WARM ADVECTION OCCURS THROUGH MID DAY
TUESDAY BEFORE COOL ADVECTION OCCURS IN THE NORTHEAST IN THE
AFTERNOON. THEREFORE EXPECT THE COOLEST TEMPERATURES IN THE
NORTHEAST CORNER. THE HIGHS TUESDAY SHOULD RANGE FROM THE UPPER 40S
TO THE MID 50S.
53
.TUESDAY NIGHT THROUGH FRIDAY NIGHT...
RIDGING ALOFT WILL BUILD EASTWARD INTO THE PLAINS ON WEDNESDAY WITH
SOUTHERLY WINDS AND WARMER TEMPERATURES IN THE MIDDLE 50S NORTH TO
THE LOWER 60S SOUTH OF I 70. AS ANOTHER SHORTWAVE TROUGH NOW IN THE
PACIFIC ADVANCES QUICKLY EASTWARD INTO THE CENTRAL HIGH PLAINS...
IT WILL RESULT IN A RAPID RETURN OF MOISTURE NORTHWARD ACROSS
CENTRAL AND EASTERN KANSAS. AS A FRONT MOVES INTO THE CWA WEDNESDAY
EVENING...SHOWERS AND SOME ISOLATED THUNDERSTORMS ARE EXPECTED TO
DEVELOP WEST TO EAST THROUGH THE NIGHT...EXITING THE SOUTHEAST
CORNER OF THE COUNTY WARNING AREA BY MIDDAY THURSDAY AS THE FRONT
AND SHORTWAVE TROUGH PUSHES SOUTH AND EAST OF THE AREA.
.SATURDAY THROUGH MONDAY...
MODEL SOLUTIONS VARYING ON HOW THEY HANDLE THE WEEKEND TROUGH THAT
DIGS INTO THE DESERT SOUTHWEST AND EJECTS OUT INTO THE PLAINS OVER
THE WEEKEND. THE PRIMARY DIFFERENCES OCCUR IN REGARD TO HOW A
NORTHERN STREAM SHORTWAVE TROUGH MOVES INTO THE PLAINS IN PROXIMITY
TO THE SHARP TROUGH IN THE SOUTHWEST. THE GFS/ENSEMBLE MEMBERS ARE
TRENDING TOWARDS KEEP THIS TROUGH AHEAD OF THE SOUTHWEST TROUGH
WHICH RESULTS IN A WEAKER AND MORE POSITIVELY TILTED TROUGH ADVANCING
ACROSS THE PLAINS WHILE THE UKMET/GEM/EC CONTINUE MORE IN LINE WITH
PAST SOLNS IN EJECTING THE PRIMARY TROUGH OUT OF THE SOUTHWEST INTO
THE CENTRAL PLAINS. FOR NOW WILL KEEP MORE CONTINUITY WITH WITH
PREVIOUS FCSTS AND LEAN TOWARDS THE EC WHICH STILL BRINGS INCREASING
POTENTIAL FOR SHOWERS AND ISOLATED THUNDERSTORMS SATURDAY AND
ESPECIALLY SATURDAY NIGHT AND SUNDAY BEFORE A DRY SLOT AND COLDER
AIR WORK INTO THE CWA SUNDAY NIGHT WITH A DECREASING POTENTIAL FOR A
RAIN SNOW MIX SUNDAY NIGHT. EITHER WY...PRECIP SHOULD END BY MONDAY
MORNING AS THE SYSTEM LIFTS QUICKLY OFF TO THE NORTHEAST AND DRIER
AIR REMAINS ACROSS THE AREA THROUGH THE DAY. AFTER HIGHS IN THE 40S
AND MIDDLE 50S FOR SATURDAY AND SUNDAY...READINGS COOL INTO THE 40S
FOR HIGHS ON MONDAY. 63
&&
.AVIATION...
FOR 06Z TAFS...VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS SURFACE
HIGH PRESSURE TRACKS SOUTHEASTWARD OVER THE AREA...RESULTING IN CALM
WINDS OVERNIGHT. WITH THESE CALM WINDS...AREAS OF BR WERE BEING
REPORTED NEAR KMHK AND COULD CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH THE POTENTIAL FOR VIS TO BRIEFLY DROP TO MVFR
CONDITIONS AT TIMES. WINDS WILL INCREASE OUT OF THE NORTHWEST BY
MID/LATE MORNING BEFORE BECOMING LIGHT ONCE AGAIN TONIGHT AS ANOTHER
SURFACE HIGH MOVES OVER THE REGION.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1031 PM MST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1243 PM MST MON FEB 4 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW NW FLOW STILL IN PLACE
FROM BRITISH COLUMBIA ACROSS THE CENTRAL HIGH PLAINS INTO THE
SOUTHERN MISSISSIPPI RIVER VALLEY. LEE TROUGH REMAINS IN PLACE OVER
EASTERN COLORADO WITH ANOTHER WEAK TROUGH AXIS OVER NW KANSAS.
OTHER THAN PASSING HIGH CLOUDS WITHIN NW FLOW TONIGHT...THERE IS
WILL BE VERY LITTLE CHANGE IN EXPECTED CONDITIONS TONIGHT VERSUS
THE LAST FEW NIGHTS...WITH LOWS GENERALLY IN 20S ACROSS THE AREA.
A SHORTWAVE RIDGE WILL BEGIN TO BUILD OVER THE INTER-MOUNTAIN
WEST BY MIDDAY TUESDAY WITHIN PROGRESSIVE FLOW. THERE MAY BE WEAK
FORCING WITHIN THE VICINITY OF THE CWA TUESDAY AFTERNOON AS A
H7-H5 VORT MAX PROGRESSES ACROSS NORTHERN EXTENT OF RIDGE IN
RESPONSE TO A DEEPENING SHORTWAVE TROUGH OVER THE NORTHERN
ROCKIES. HOWEVER...WITH DEEP DRY AIR MASS IN PLACE THIS SHOULD ONLY
RESULT IN INCREASING HIGH CLOUD COVER BY LATE TUESDAY AFTERNOON.
WITH ALL OF THIS IN MIND...I AM ANTICIPATING MILD/DRY CONDITIONS
AGAIN ON TUESDAY WITH HIGHS IN THE MID-UPPER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 223 PM MST MON FEB 4 2013
TUESDAY NIGHT-FRIDAY...SHORT WAVE RIDGE WILL BE IN PLACE ACROSS THE
AREA DURING THE THE BEGINNING OF THE PERIOD LEADING TO CONTINUED DRY
CONDITIONS THROUGH WEDNESDAY. A SHORT WAVE TROUGH WILL MOVE ACROSS
NEBRASKA ON WEDNESDAY...BUT GIVEN STABLE CONDITIONS EXPECTED ACROSS
THE AREA DO NOT EXPECT MUCH OF A RESPONSE ACROSS THE CWA. WHILE
MODELS SUGGEST INCREASE IN ELEVATED INSTABILITY OVERNIGHT WEDNESDAY
ACROSS SOUTHERN AND EASTERN KANSAS...AFOREMENTIONED TROUGH WILL
LIKELY FORCE H85 AND H7 FRONTAL ZONE WELL TO THE SOUTH OF THE AREA
WHICH WOULD MAKE PRECIPITATION DEVELOPING AS FAR NORTH OF THE CWA
UNLIKELY. OTHERWISE ABOVE NORMAL CONDITIONS ARE EXPECTED THROUGH THE
PERIOD.
IN THE EXTENDED(FRIDAY NIGHT-MONDAY)...MAIN CONCERN FOR THE PERIOD
WILL BE THE DEVELOPMENT AND EVOLUTION OF STRONG H5 TROUGH DURING THE
WEEKEND AND ASSOCIATED PRECIP/WINTER STORM IMPACTS THROUGH MONDAY.
THERE ARE TWO DISTINCT CAMPS WITH RESPECT TO 12Z OPERATIONAL AND
ENSEMBLE GUIDANCE. THE ECMWF/GEM AND GEM MEAN INDICATING A FARTHER
EAST MORE CONSOLIDATED SYSTEM IMPACTING THE AREA WHILE GFS AND
MAJORITY OF ITS ENSEMBLE MEMBERS SUGGESTING A FURTHER WEST SYSTEM
THAT IS SOMEWHAT SPLIT BETWEEN THE SOUTHWEST AND NORTHEAST. AT THIS
POINT...HARD TO PICK A FAVORITE CLUSTER WHILE TOTALLY IGNORING OTHER
POSSIBLE SCENARIO. THE ECMWF GROUP WOULD SUPPORT A SIG PRECIP THREAT
ACROSS NORTHERN CWA WHILE GFS SOLUTION WOULD RESULT IN MUCH LESS
PRECIP AND OVERALL SMALLER IMPACT. FOR THE TIME BEING...THINK
KEEPING POPS IN THE CHANCE RANGE IS WARRANTED AND STAYING TOWARDS
CONSENSUS DATA WARRANTED UNTIL BETTER SIGNAL DEVELOPS AND CONFIDENCE
INCREASES. GENERAL CONSENSUS SUGGEST MUCH ABOVE NORMAL TEMPERATURES
AND POSSIBLY A FEW THUNDERSTORMS MAY DEVELOP AHEAD OF SYSTEM BEFORE
SNOW DEVELOPS AS SYSTEM EXITS AND COLDER AIR MOVES IN. WHILE THERE
IS POTENTIAL FOR A SIGNIFICANT WINTER STORM...FOR REASONS MENTIONED
ABOVE FEEL IT IS TOO EARLY TO REALLY KEY IN ON THIS SOLUTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 932 PM MST MON FEB 4 2013
VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS AT KGLD AND
KMCK. LIGHT WEST WIND WILL SHIFT TO THE NORTH LATE TUESDAY MORNING
AT BOTH SITES AS A HIGH PRESSURE BUILDS IN BEHIND A TROUGH MOVING
EAST OF THE AREA. WIND WILL SHIFT SOUTH TUESDAY EVENING IN
RESPONSE TO A SURFACE TROUGH IN EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM
AVIATION...032
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1136 PM CST MON FEB 4 2013
.UPDATE...
ISSUED AT 1128 PM CST MON FEB 4 2013
UPDATED THE AVIATION SECTION FOR THE 06Z TAF ISSUANCE.
UPDATE ISSUED AT 902 PM CST MON FEB 4 2013
SUBTLE CHANGES MADE TO THE FIRST PERIOD /EVENING AND OVERNIGHT/
FORECAST PRIMARILY TO HANDLE TEMPERATURE/DEWPOINT/SKY COVER/WIND
CHANGES ASSOCIATED WITHT HE PASSAGE OF THE WEAK COLD FRONT THROUGH
THE REGION. THE 5KM DOWNGRADED NAM-WRF...3KM HRRR AND 2.5 KM GFS
LAMP SEEM TO HANDLE THE MOISTURE AND TEMPERATURE FIELDS THE BEST
THIS EVENING. ANY FOG DEVELOPMENT THIS EVENING WILL BE
TRANSITORY...BUT WE MAY SEE MORE FROST OVERNIGHT SHOULD THE CLOUDS
THIN SOMEWHAT BEHIND THE FRONT OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 305 PM CST MON FEB 4 2013
MINOR CLIPPER SYSTEM BRINGING LIGHT RAIN TO THE AREA THIS
AFTERNOON...BUT IT IS BARELY MEASURING...AND THEN ONLY HERE AND
THERE. WOULD EXPECT THE MAIN AREA OF LIGHT RAIN TO BE SOUTHEAST OF
THE AREA BY 00Z...BUT SOME MORE SHOWERY PRECIPITATION THAT HAS
DEVELOPED NORTH OF THE LIGHT RAIN...MAY LINGER IN THE FAR EAST OR
SOUTHEAST INTO THE EARLY EVENING.
AS THE CLIPPER SYSTEM SHIFTS EASTWARD UP THE OHIO VALLEY...THE
COLD FRONT WILL BE PUSHED MORE EAST THAN SOUTH...BASICALLY
DRAGGING ITS HEELS ACROSS THE AREA. HAVE SLOWED DOWN THE WIND
SHIFT A BIT...BUT IT SHOULD BE THROUGH THE AREA BEFORE DAYBREAK
TUESDAY. MAY SEE SOME CLEARING AHEAD OF THE FRONT...AND THEN AT
LEAST A TRANSIENT INCREASE IN LOW CLOUDS OVERNIGHT BEHIND THE
FRONT. AS SURFACE HIGH PRESSURE SETTLES OVERHEAD NEAR 12Z
TUESDAY...WILL HAVE TO MONITOR FOR FOG OR LOW CLOUD DEVELOPMENT
BEHIND THE INITIAL BATCH OF POST FRONTAL CLOUDS. THE BOTTOM LINE
IS THAT LOW TEMPERATURES WILL BE DIFFICULT TO CALL. WENT NEAR
CONSENSUS OF AVAILABLE 12Z GUIDANCE WHICH IS A BIT COOLER THAN
PREVIOUS FORECAST...BUT IF CLOUDS/FOG PERSIST IT MAY BE TOO COOL.
THE MODELS AGREE IN QUICKLY DEVELOPING RATHER STRONG SOUTHWEST
WINDS AHEAD OF WHAT SHOULD BE THE FINAL CLIPPER SYSTEM THIS WEEK.
THIS CLIPPER WILL TRACK WELL TO OUR NORTHEAST...BUT THE MODELS
HAVE TRENDED TOWARD MORE OF A FRONTAL PASSAGE TUESDAY EVENING IN
OUR AREA. WITH SOUTHWEST WINDS AND PLENTY OF SUNSHINE
EXPECTED...HAVE NO PROBLEM GOING WITH THE WARMER 12Z CONSENSUS FOR
HIGHS.
WEAK SURFACE HIGH PRESSURE WILL QUICKLY SETTLE OVER THE AREA BY
12Z WEDNESDAY...BUT THE MODELS AGREE THAT THIS HIGH WILL LINGER A
BIT LONGER DUE TO A TRANSITION TOWARD ZONAL FLOW ALOFT. THE MODELS
ALSO AGREE ON A TREND SLOWER WITH THE ARRIVAL OF CLOUDS FOR
THURSDAY...SO SHOULD NOT SEE MUCH OF AN INCREASE IN CLOUDS UNTIL
NEAR 12Z THURSDAY.
STAYED CLOSE TO CONSENSUS FOR LOWS TUESDAY NIGHT. WEDNESDAY WILL
HAVE PLENTY OF SUNSHINE...BUT AN EAST WIND MAY HOLD TEMPERATURES
DOWN A BIT. CONSENSUS GUIDANCE SEEMS A BIT COOL...BUT DID NOT
STRAY TOO FAR FROM IT. WILL HAVE WARM ADVECTION ONGOING WEDNESDAY
NIGHT...SO WOULD BET ON THE WARMER MET GUIDANCE.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 305 PM CST MON FEB 4 2013
THE PASSAGE OF A WEAK COLD FRONT THURSDAY INTO THURSDAY NIGHT WILL
BRING A GOOD CHANCE OF SHOWERS TO THE PAH FORECAST AREA. ECMWF AND
GEM SHOW THE FRONT PUSHING ON THROUGH THE REGION THURSDAY
NIGHT...WHILE GFS HANGS THE FRONT OVER OUR AREA INTO FRIDAY...THUS
LINGERING SHOWERS INTO FRIDAY. PREFER THE MORE PROGRESSIVE
ECMWF/GEM SOLUTIONS FOR NOW...AND KEPT FRIDAY DRY. TEMPERATURES
WILL BE COOLER BUT STILL A LITTLE ABOVE NORMAL ON FRIDAY WITH WINDS
OUT OF THE NORTH/NORTHEAST.
WINDS WILL GRADUALLY TURN SOUTHERLY BY LATE SATURDAY INTO SATURDAY
NIGHT. THESE WINDS WILL HELP BRING MORE MOIST AIR BACK INTO THE
AREA AHEAD OF OUR NEXT WEATHER SYSTEM. ECMWF IS SLOWER THAN THE GFS
BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS INTO THE
GREAT LAKES REGION...WITH ECMWF OVER SOUTHEAST NEBRASKA AT 00Z
MONDAY...AND GFS OVER THE SOUTHERN GREAT LAKES REGION AT THE SAME
TIME. BOTH MODELS SHOW A LITTLE PRECIP IN AT LEAST WESTERN PORTIONS
OF THE FA LATE SATURDAY NIGHT...BUT MODELS HAVE BEEN TRENDING SLOWER
WITH EACH RUN...SO WILL KEEP SATURDAY NIGHT DRY. BOTH MODELS SPREAD
WIDESPREAD SHOWERS AND SOME THUNDERSTORMS ACROSS THE REGION THROUGH
THE DAY SUNDAY...CONTINUING INTO SUNDAY NIGHT. BY 00Z TUESDAY...THE
MODELS ARE IN BETTER AGREEMENT ON PLACEMENT OF THE COLD FRONT JUST
SOUTHEAST OF THE FA...AND THIS KEEPS SOME LIGHT QPF ACROSS OUR
REGION MONDAY...ESPECIALLY ACROSS THE SOUTHEAST HALF OF THE AREA.
WENT WITH CHANCE TO SLIGHT CHANCE OF SHOWERS ON MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1128 PM CST MON FEB 4 2013
MVFR VSBYS AT KCGI BETWEEN 09-15Z...OTHERWISE VFR THROUGH THE PERIOD.
MVFR CIGS THROUGH 07Z AT KPAH...THEN VFR CIGS THROUGH THE PERIOD...
BUT COULD SEE MVFR VSBYS BETWEEN 10-15Z. AT KEVV AND KOWB MVFR
CIGS POSSIBLY DIPPING INTO IFR TERRITORY THROUGH 08-09Z...MVFR
VSBYS THROUGH 15-16Z...THEN VFR. WEST TO NORTHWEST WINDS AOB 5
KTS WILL BECOME SOUTHWEST AOB 10 KTS AFTER 15-16Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...JP
PUBLIC...SMITH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EST TUE FEB 5 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM EST TUE FEB 5 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER
HUDSON BAY AND A RIDGE FROM THE ROCKIES TO BC RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A SHORTWAVE TROUGH WAS MOVING EASTWARD
THROUGH NRN IL WHILE A WEAKE SHRTWV TO THE NORTH THAT BROUGH THE
LIGHT SNOW TO UPPER MI HAD MOVED INTO NRN LOWER MI. AT THE
SFC...NRLY WINDS WERE INCREASING THROUGH UPPER MI AS A TROUGH MOVES
S THROUGH THE AREA AND A LOW MOVES EAST FROM NEAR THE SAULT. A BAND
OF SNOW SHOWERS SUPPORTED BY LOW LEVEL CONV NEAR THE TROUGH HAS
SAGGED THROUGH THE NORTH PORTION OF THE CWA.
EXPECT MAINLY LIGHT TO MODERATE NW FLOW WIND PARALLEL LES BANDS
TONIGHT. 850 MB TEMPS AROUND -20C WITH MUCH OF THE CLOUD LAYER IN
THE DGZ WILL SUPPORT HIGHER SNOW/WATER RATIOS AOA 25/1.
HOWEVER...VERY DRY AIR UPSTREAM AND INVERSION HEIGHTS AOB 4K FT WILL
ALSO LIMIT LES INTENSITY. SO...SNOWFALL AMOUNTS IN THE 1 TO 3 INCH
RANGE ARE EXPECTED...GREATEST OVER THE EAST. HIGHER RES MODELS
SUGGEST THAT DIMINISHING WINDS LATE TONIGHT MAY ALLOW DEVELOPMENT OF
A MESO-LOW OVER SE LAKE SUPERIOR. THERE IS LOW CONFIDENCE WHER OR IF
THIS WOULD MOVE ASHORE AS WINDS SLOWLY BACK IN RESPONSE TO THE
DEPARTING RIDGE TO THE SOUTH.
THE FCST KEEPS TEMPS TOWARD THE LOWER END OF GUIDANCE INLAND WEST AS
THERE MAY BE ENOUGH OF A PERIOD OF CLEAR TO PARTLY CLOUDY AS MID
CLOUDS PASS FARTHER TO THE NORTH...TO ALLOW TEMPS TO DROP OFF WELL
BELOW ZERO.
UPPER LEVEL DIV ASSOCIATED WITH A DEVELOPING 250-300 MB JET STREAK
FROM THE NRN LAKES TO NEW ENGLAND AND ASSOCIATED MID LEVEL FGEN TO
THE SOUTH INTO NW WI BY LATE TUE AFTERNOON WILLS SUPPORT AN AREA OF
LIGHT SNOW EXPANDING TOWARD UPPER MI. HOWEVER...ONLY CHANCE POPS ARE
EXPECTED INTO THE WEST BY 00Z/THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM EST TUE FEB 5 2013
FIRST FEATURE OF NOTE FOR THIS PERIOD WILL BE THE BROAD WAA AT
THE START OF THE PERIOD AHEAD OF AN INVERTED TROUGH SLIDING
SOUTHEAST THROUGH THE NORTHERN/CENTRAL PLAINS. INITIAL SNOW WILL BE
ONGOING AT THE START OF THE PERIOD OVER WESTERN UPPER
MICHIGAN...WHICH WILL BE LARGELY FOCUSED ALONG THE BROAD H850-600
WAA/ISENTROPIC ASCENT AND RIGHT REAR OF THE UPPER JET MOVING EAST
ACROSS THE CWA. THE BEST/SHARPEST LOW LEVEL WAA GRADIENT DOES LOOK
TO BE FARTHER SOUTH WITH THE 12Z RUNS...MORE IN WISCONSIN...SO
THINKING THAT A FARTHER SOUTH TREND TO THE QPF/SNOW IS WARRANTED.
THAT BEING SAID...THERE ARE SOME HINTS OF THE MID LEVEL FGEN TRYING
TO FOCUS/STALL NEAR SOUTHERN LAKE SUPERIOR...WHICH COULD TRY TO
INCREASE SNOWFALL AMOUNTS SOME.
WITH THE INITIAL WAA SNOW SLIDING EAST ON THURSDAY...A SHORTWAVE IS
EXPECTED TO DROP SOUTHEAST FROM THE NORTHERN PLAINS ON WEDNESDAY
NIGHT INTO THURSDAY. SHORTWAVE LOOKS TO BE A LITTLE STRONGER AND
FARTHER SOUTH THAN YESTERDAY...WHICH HAS SOME INFLUENCE ON THE
OVERALL FORECAST. GFS/ECMWF/GEM SEEM TO BE IN GOOD AGREEMENT WITH
THE TRACK/INTENSITY OF THE SHORTWAVE...WHILE THE NAM IS A LITTLE
FLATTER AND FARTHER NORTH. WILL TREND AWAY FROM THE NAM AND TOWARDS
THE OVERALL CONSENSUS. AS THE SHORTWAVE DIGS THROUGH SOUTHERN WI AND
NORTHERN ILLINOIS...THE LOW BEGINS TO WRAP UP NEAR THE LOWER GREAT
LAKES AND FOCUSES THE BETTER FORCING AND PRECIPITATION FARTHER TO
THE SOUTH ON THURSDAY. BUT...THERE SHOULD STILL BE ENOUGH LINGERING
MOISTURE AND BROAD FORCING TO LEAVE SCATTERED SNOW SHOWERS BEHIND
THE SYSTEM. IN ADDITION...SHOULD SEE SOME LAKE ENHANCEMENT OFF LAKE
SUPERIOR AS H850 TEMPS ARE AROUND -12C AND WINDS ARE OUT OF THE
NORTHEAST DIRECTION. THIS SHOULD CONTINUE INTO THURSDAY EVENING
BEFORE DIMINISHING OVERNIGHT AS THE DEEPER MOISTURE DEPARTS. OFF OF
LAKE MICHIGAN...WINDS LOOK TO BE A LITTLE MORE EASTERLY WEDNESDAY
NIGHT INTO THURSDAY MORNING...WHICH WILL ALSO ASSIST IN SOME
ENHANCEMENT FROM MENOMINEE THROUGH MANISTIQUE. WITH THE RECENT
SHIFTS IN THE FORECAST...THE WIND FIELD HAS BEEN FLUCTUATING GREATLY
WHICH PRODUCES LIMITED CONFIDENCE ON LAKE ENHANCEMENT LOCATIONS.
WITH THE FARTHER SOUTH SHIFT...THINKING MOST LOCATIONS WILL SEE
1-4 INCHES FROM WEDNESDAY AFTERNOON THROUGH THE DAY THURSDAY.
DUE TO IT/S CLOSER PROXIMITY TO BEST LOWER LEVEL WAA AND LAKE
ENHANCEMENT...COULD SEE MENOMINEE COUNTY APPROACHING THE 3 INCHES IN
24HRS ADVISORY CRITERIA WEDNESDAY NIGHT INTO THURSDAY MORNING. WILL
CONTINUE TO MENTION IN THE HWO...BUT WILL FOCUS THE WORDING MORE
TOWARDS THE SOUTH CENTRAL AND AREAS NEAR LAKE MICHIGAN.
ONE FINAL THING TO NOTE FOR THURSDAY IS THE POTENTIAL FOR MID LEVEL
DRY AIR TO ATTEMPT TO CUT OUT SOME OF THE ICE CRYSTALS IN THE
CLOUDS. IF THIS OCCURS...IT COULD LEAD TO BRIEF PERIODS OF FREEZING
DRIZZLE...BUT CONFIDENCE IS EXTREMELY LOW FOR OCCURRING AT THIS
POINT.
HIGH PRESSURE RIDGE THEN MOVES OVER THE AREA FOR LATE THURSDAY
NIGHT INTO FRIDAY NIGHT AND LEADS TO QUIET WEATHER OVER THE CWA.
NEXT WAVE BRUSHES THE NORTHERN HALF OF THE CWA ON SATURDAY AND WILL
CONTINUE TO MENTION SLIGHT OR LOW CHANCE POPS AS THAT PASSES
THROUGH.
UNCERTAINLY IN THE FORECAST GREATLY INCREASES AFTER SATURDAY...AS
MODELS HAVE BEEN DIFFERING ON THE HANDLING OF THE ENERGY EXITING THE
SOUTHWEST CONUS AND MOVING THROUGH THE GREAT LAKES. 00Z ECMWF AND
12Z GFS HAVE COME INTO BETTER AGREEMENT WITH THIS FEATURE
AND PULL A 990S MB LOW THROUGH THE UPPER GREAT LAKES REGION ON
MONDAY INTO MONDAY NIGHT. ENSEMBLE MEMBERS OF BOTH OF THOSE RUNS
VARY GREATLY...WHICH MATCHES UP WELL WITH THE VARIABILITY OVER THE
LAST DAY. WITH 12Z GEM/UKMET ALSO TRENDING TOWARDS A LOW
MOVING THROUGH THE AREA...WILL TREND POPS UP DURING THAT TIME
FRAME TO ADDRESS THE INCREASED POTENTIAL FOR SNOW. IF THE CURRENT
GFS/ECMWF FORECAST IS CORRECT...SOME LOCATIONS IN UPPER MICHIGAN
COULD SEE A HEAVY SNOWFALL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE FEB 5 2013
EXPECT MAINLY MVFR CONDITIONS AT CMX/IWD WITH LIGHT NRLY FLOW LAKE
EFFECT SNOW EXPECTED INTO TONIGHT WITH ONLY BRIEF PERIODS OF IFR
VSBY POSSIBLE. WED...BACKING WINDS TO SW AHEAD OF ANOTHER LOW PRESSURE
SYSTEM WILL ALLOW CONDITIONS TO IMPROVE TO VFR. LAKE EFFECT CLOUDS
WILL BE LATER TO ARRIVE AT SAW THIS AFTERNOON BUT SHOULD ALSO DROP
CONDITIONS INTO THE MVFR RANGE. WITH MORE OF A NW THEN W FLOW
OVERNIGHT CONDITIONS MAY EDGE UP CLOSE TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST TUE FEB 5 2013
NORTH WINDS TO 30 KNOTS LATE THIS AFTERNOON AND EVENING AND AREAS OF
FREEZING SPRAY WILL GRADUALLY DIMINISH OVERNIGHT AS A RIDGE BUILDS
INTO THE AREA. ENE WINDS INTO THE 15 TO 25 KNOT RANGE ARE ALSO
EXPECTED LATE WED NIGHT INTO THU AS A LOW PRESSURE SYSTEM MOVES
THROUGH SOUTHERN WI. OTHERWISE...WINDS ARE EXPECTED TO REMAIN BELOW
25 KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1152 PM EST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EST MON FEB 4 2013
LIGHT TO MODERATE SNOW WITH A CLIPPER SYSTEM WILL BE THE MAIN STORY
IN THE SHORT TERM.
LATE THIS AFTERNOON...BACKING WINDS TO A WESTERLY DIRECTION ARE
PUSHING REMAINING LES OFFSHORE ACROSS EASTERN UPPER MI...WITH A FEW
TRANSIENT LES BANDS REMAINING NEAR THE SHORE. HAVE THUS CANCELED THE
LES WARNING...THOUGH A COUPLE MORE INCHES OF SNOW WILL BE POSSIBLE
THROUGH THIS EVENING.
TONIGHT...CLEARING SKIES AND LIGHT WINDS WILL ALLOW FOR QUICK
RADIATIONAL COOLING EARLY THIS EVENING...ESPECIALLY ACROSS CENTRAL
AND EASTERN UPPER MI. LOWERED THE MIN TEMPS GIVEN A SIMILAR SETUP TO
LAST NIGHTS SUBSTANTIAL COOLING.
MAIN FOCUS IS ON A WEAK CLIPPER SYSTEM MOVING SOUTHEAST ACROSS THE
UPPER GREAT LAKES TONIGHT INTO TUESDAY. MODEL AGREEMENT HAS BEEN A
LITTLE FUZZY...WITH THE RUC PLACING THE BULK OF PRECIP IN UPPER
MI...THE NAM AND REGIONAL GEM PUTTING MOST ALONG THE WI BORDER...AND
THE GFS PLACING NEARLY ALL PRECIP IN NORTHERN WI. HAVE OPTED TO GO
WITH THE MIDDLE GROUND AS THE CONSENSUS TREND HAS BEEN TO BRING
THINGS SLIGHTLY NORTH.
PRECIP WILL BE FOCUSED ALONG AN AREA OF 850 TO 700MB FRONTOGENESIS.
THE MOST ACTIVE LAYER IS NOT CLEAR...BUT BELIEVE THE BEST FORCING
WILL BE BETWEEN 750 AND 800MB. A FAIRLY DECENT LAYER OF 150 TO 200MB
WITHIN THE BEST RISING MOTION WILL BE IN THE DGZ. BOOSTED SNOW
RATIOS TO THE LOW 20S GIVEN THIS SET UP. OVERALL...KEPT TOTAL QPF OF
0.1 TO 0.2 INCHES...PRODUCING 1 TO 3 INCHES...WITH UP TO 4 INCHES
POSSIBLE. CURRENT THINKING IS THAT THE HIGHEST AMOUNTS WILL BE ALONG
THE WI BORDER...THOUGH WOULD NOT BE SURPRISED IF IT IS PUSHES 50
MILES EITHER WAY GIVEN THE MODEL INCONSISTENCIES AND NARROW FEATURE.
HAVE ISSUED AN SPS TO COVER THE EVENT AS THERE IS TOO LOW OF
CONFIDENCE TO PUT IN ANY ADVISORIES ATTM. EXPECT SNOW TO BEGIN
ACROSS THE WEST AROUND MIDNIGHT AND SPREAD EAST OVERNIGHT.
THE MAIN SNOW SHIELD WILL DIMINISH THROUGHOUT THE MORNING. THEN...A
WELL DEFINED TROUGH BEHIND THE LOW WILL MOVE SOUTH ACROSS THE
NORTHERN CWA IN THE AFTERNOON. WOULD NOT BE SURPRISED IF A QUICK
BURST OF HEAVY SNOW ACCOMPANIES THIS TROUGH.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EST MON FEB 4 2013
NORTHWEST FLOW ALOFT WILL BE IN PLACE FOR THE START OF THE
PERIOD...AS A RIDGE REMAINS IN PLACE OVER THE WESTERN CONUS AND A
TROUGH IS SETUP IN EASTERN CANADA. WITH NORTHWEST FLOW AND H850
TEMPS AROUND -19C...EXPECT SOME LAKE EFFECT SNOW BEHIND THE CLIPPER
SYSTEM THAT MOVES THROUGH ON TUESDAY. THINKING THERE WILL BE ENOUGH
MOISTURE LEFT BEHIND THE CLIPPER TO LEAD TO A BRIEF UPTICK IN THE
LAKE EFFECT INTENSITY DURING THE LATER HALF OF THE EVENING AND INTO
THE FIRST PART OF THE OVERNIGHT HOURS. DON/T EXPECT ANYTHING TOO
SIGNIFICANT DUE TO WEAKENING WINDS WITH THE APPROACHING
SURFACE RIDGE AND INVERSION HEIGHTS IN THE 5-7KFT RANGE...BUT WITH
THE DGZ LOCATED RIGHT IN THE BEST OMEGA AND CLOUD LAYER...WOULD
THINK THAT THE NORTHWEST WIND FAVORED LOCATIONS WOULD SEE A DUSTING
TO A FLUFFY COUPLE OF INCHES OF SNOW.
THE SURFACE RIDGE WILL LEAD TO MORE VARIABLE AND BACKING WINDS
TOWARDS WEDNESDAY MORNING...WHILE THE NEXT CLIPPER SYSTEM
APPROACHES FROM THE DAKOTAS ON WEDNESDAY. THE INCREASING SOUTHERLY
FLOW WILL LEAD TO WARM AIR ADVECTION CLOUDS AND PRECIPITATION
SPREADING ACROSS WEDNESDAY INTO WEDNESDAY NIGHT...WITH THE LOW
MOVING THROUGH THE GREAT LAKES REGION LATE WEDNESDAY NIGHT INTO
THURSDAY. MODELS SEEM FAIRLY CONSISTENT ON THE SHORTWAVE PRODUCING
THIS FEATURE MOVING THROUGH WISCONSIN...ALONG WITH THE BEST/SHARPEST
LOWER LEVEL FORCING. BUT EXPECT THERE TO BE ENOUGH WAA AND MID LEVEL
FGEN TO LEAD SNOW ALONG AND NORTH OF THE WARM FRONT. SEEMS LIKE THE
BEST MID LEVEL FGEN IS FAIRLY PROGRESSIVE ACROSS THE CWA...BUT DOES
TRY TO PIVOT SOMEWHAT ACROSS NORTHERN LAKE SUPERIOR AND NEAR THE
KEWEENAW PENINSULA. WILL BE INTERESTING TO SEE IF THIS PIVOT
CONTINUES AND WHERE IT LINES UP IN FUTURE RUNS...AS IT COULD LEAD TO
SOME INCREASING SNOWFALL AMOUNTS. IN ADDITION...WITH THE SOUTHERLY
LOW LEVEL WIND AND H850 TEMPS AROUND -9C SHOULD BE ENOUGH FOR LAKE
ENHANCEMENT OFF LAKE MICHIGAN. WIND FIELDS VARY FAIRLY SIGNIFICANTLY
IN THE MODELS...SO DIDN/T TRY TO GET TOO SPECIFIC OTHER THAN
TWEAKING POPS/QPF UP SLIGHTLY IN SCHOOLCRAFT/LUCE COUNTIES.
OTHERWISE...OVERALL CONSENSUS OF THE MODELS LOOKS TO PRODUCE
0.15-0.25 INCHES OF QPF...WITH THE HIGHEST AMOUNTS OVER THE
SOUTH/EASTERN CWA. THIS DOES SEEM TO MATCH UP WITH THE NORTH EDGE OF
THE BETTER H850-700 WAA AND RESULTING FGEN...ALONG WITH THE RIGHT
REAR OF THE UPPER JET. THIS PRODUCES A GENERAL 2-4INCHES OF SNOW
ACROSS THE AREA AND WILL CONTINUE TO MENTION IN THE HWO.
BEHIND THE CLIPPER...THERE DOESN/T LOOK TO BE MUCH COLD AIR SURGING
IN DUE TO THE UPPER RIDGE SHIFTING EAST AS AN UPPER TROUGH DIGS
INTO THE WEST COAST. THINKING THIS WILL LEAD TO A QUIETER PERIOD
FOR FRIDAY INTO THE FIRST PART OF SATURDAY AS A HIGH PRESSURE
RIDGE NEAR JAMES BAY STRETCHES SOUTHWEST ACROSS THE UPPER GREAT
LAKES. WITH LIMITED COLD AIR AND WINDS BACKING TO THE
SOUTHWEST...EXPECT A DIMINISHING TREND TO ANY LAKE EFFECT ON
THURSDAY NIGHT AND WILL GO WITH DRY CONDITIONS ON FRIDAY AND FRIDAY
NIGHT.
NEXT SHORTWAVE WILL BRUSH NORTHERN LAKE SUPERIOR ON SATURDAY AND
DRAG A SURFACE TROUGH ACROSS THE CWA. THIS SHOULD LEAD TO A LIGHT
DUSTING OF SNOW...WITH MOST LOCATIONS SEEING LESS THAN AN INCH.
AFTER THIS SYSTEM THE FORECAST BECOMES UNCERTAIN...AS MODELS DIFFER
IN HOW THE ENERGY EJECTS OUT OF THE UPPER TROUGH IN THE SW CONUS.
WILL CONTINUE TO FOLLOW A GENERAL CONSENSUS FOR POPS...WITH THE BEST
CHANCES FOR ACCUMULATING SNOW OVER THE SOUTHEAST HALF OF THE CWA.
AS FOR TEMPS...THE LONG TERM PART OF THE FORECAST LOOKS TO BE AT OR
SLIGHTLY ABOVE NORMAL FOR TEMPERATURES WITH THE COLDEST DAY/NIGHT
ON TUESDAY NIGHT AND WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1150 PM EST MON FEB 4 2013
OVERNIGHT...FOCUS IS ON LOW PRES AND ASSOCIATED AREA OF SNOW MOVING
SE TOWARD THE AREA. SNOW WILL BEGIN AT OR NEAR THE START OF THE FCST
PERIOD AT KIWD...SOON AFTER AT KCMX AND LATER IN THE NIGHT AT KSAW.
VIS WILL LIKELY FALL TO LOW IFR AT KIWD FOR SEVERAL HOURS OVERNIGHT
AND PERHAPS EVEN TO LIFR FOR A TIME. KCMX AND KSAW SHOULD BE A
LITTLE MORE REMOVED FROM THE HEAVIER SNOW...BUT STILL EXPECT A
PERIOD OF IFR CONDITIONS PER UPSTREAM OBS...AND CAN`T COMPLETELY
RULE OUT A BRIEF PERIOD OF LIFR. WINDS WILL BE LIGHT AS THE SNOW
FALLS...SO BLSN IS NOT A CONCERN. FROM NW TO SE...SNOW WILL DIMINISH
AND POSSIBLY END FOR A TIME THIS MORNING. HOWEVER...AS WINDS SHIFT N
TO NW TODAY...SOME LAKE EFFECT SNOW SHOWERS WILL DEVELOP WITH MVFR
CONDITIONS GENERALLY PREVAILING. BETTER UPSLOPE AT KIWD MAY LEAD TO
A PERIOD OF IFR CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST MON FEB 4 2013
EXPECT WEST WINDS OF UNDER 25 KNOTS TO SLOWLY DIMINISH THROUGHOUT
THE NIGHT ACROSS THE EASTERN LAKE. WINDS WILL THEN VEER NORTH TO 20
TO 30 KNOTS BEHIND A TROUGH TUESDAY AFTERNOON INTO TUESDAY EVENING.
OTHERWISE...PLAN ON WINDS UNDER 20 KNOTS THROUGH THE REST OF THE
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TK
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...TK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1203 AM CST TUE FEB 5 2013
.AVIATION...06Z KGRI TAF...VFR CONDITIONS WILL PREVAIL AT KGRI
FOR THE NEXT 24 HOURS WITH ONLY A FEW MID/HIGH LEVEL CLOUDS
EXPECTED TO PASS ACROSS THE TERMINAL. A SURFACE TROUGH PASSING
ACROSS THE STATE EARLY THIS MORNING WILL RESULT IN GENERALLY LIGHT
AND VARIABLE WINDS THROUGH ABOUT 05/16Z...BEFORE WINDS SHIFT AND
BECOME NORTHWESTERLY ON THE BACKSIDE OF THIS TROUGH LATE TUESDAY
MORNING.
&&
.PREV DISCUSSION... /ISSUED 408 PM CST MON FEB 4 2013/
SHORT TERM...TONIGHT AND TUESDAY.
WE REMAIN IN NORTHWEST FLOW ALOFT FOR THE SHORT TERM. A SURFACE COLD
FRONT THAT PASSED TO THE SOUTHWEST EDGE OF THE CWA TODAY HAS STALLED
AND BEGUN TO MOVE BACK TO THE EAST. EARLIER STRATUS BEHIND THE COLD
FRONT IS CONTINUING TO ERODE...WITH MAINLY THE EASTERN CWA THE ONLY
AREA LEFT WITH APPRECIABLE STRATUS.
MODELS HAVE NOT BEEN HANDLING THE STRATUS WELL AND THE ONLY MODEL TO
LATCH ON TO IT WELL THIS MORNING WAS THE HRRR. THE STRATUS IS
BURNING OFF ON THE WESTERN EDGE FASTER THAN THE HRRR INDICATES.
ALSO...THE HRRR INDICATES A WESTWARD PUSH THIS EVENING BEFORE
SCOURING OUT FOR GOOD AS THE WARM FRONT/TROUGH MOVES EAST. SINCE THE
HRRR IS LOSING ITS GRIP ON THE SITUATION...I AM BANKING ON THE
CONTINUED EASTWARD PROGRESSION OF THE WESTERN EDGE OF THE STRATUS.
MODELS DO NOT INDICATE ANY REDUCED VISIBILITY ALONG THE WESTERN EDGE
OF THE STRATUS TONIGHT...EXCEPT THE HRRR...BUT THE HRRR ALSO
INDICATED REDUCED VISIBILITY THIS MORNING ALONG THE WESTERN EDGE OF
THE STRATUS AND THIS DID NOT COME TO FRUITION...SO I AM DISCARDING
THIS SOLUTION...AS WIND WILL BECOME WEST AND INCREASE IN STRENGTH
SOMEWHAT AS WELL.
NUDGED TEMPERATURES UP A BIT FOR TONIGHT WITH A SLIGHT INCREASE TO
WIND SPEED BEHIND THE WARM FRONT.
STILL BANKING ON A WARMER DAY WITH INCREASED 850 MB TEMPERATURES FOR
TUESDAY...WITH PLENTY OF SUN. WIND GUSTS COULD INCREASE A BIT FROM
INCREASED LAPSE RATES...BUT NOTHING THAT WOULD BE CONSIDERED
PARTICULARLY OUT OF THE ORDINARY FOR CENTRAL NEBRASKA.
LONG TERM...TUESDAY EVENING THROUGH NEXT MONDAY. CERTAINLY THE
MOST INTRIGUING ASPECT OF THIS 6-DAY PERIOD IS THE POTENTIALLY/
REPEAT POTENTIALLY/ IMPACTFUL SYSTEM IN THE SATURDAY-SUNDAY NIGHT
TIME FRAME...AND WHETHER IT RESULTS IN ACCUMULATING SNOW AND/OR
EVEN SOME THUNDERSTORMS. HOWEVER...GIVEN THE CONSIDERABLE
UNCERTAINTY AT THIS DAY 5-6 RANGE...WILL NOT GET TOO CARRIED AWAY
AT THIS TIME. IN THE NEARER PERIODS...WILL HAVE TO WATCH FAR
SOUTHEAST COUNTIES FOR A POSSIBLE GLANCING BLOW OF SHOWERS/WEAK
THUNDERSTORMS WEDNESDAY NIGHT. OTHERWISE...AT LEAST FOR THE
WEDNESDAY-SATURDAY TIME FRAME...CONFIDENCE IS FAIRLY HIGH IN A
MILD TEMPERATURE REGIME WITH HIGHS GENERALLY AVERAGING UPPER 40S-
MID 50S.
STARTING OFF TUESDAY NIGHT...SHOULD BE BE A QUIET PERIOD. 12Z
MODELS SUCH AS THE NAM/GFS/ECMWF ARE IN GOOD AGREEMENT DEPICTING
QUASI-ZONAL FLOW ALOFT/WEAK SHORTWAVE RIDGING. AT THE
SURFACE...INITIALLY LIGHT/VARIABLE BREEZES WILL GRADUALLY BECOME
STEADIER AND FROM THE SOUTH...INCREASING TO AT LEAST 10-15 MPH IN
MANY AREAS AFTER MIDNIGHT AS A SURFACE RIDGE MIGRATES EAST AND A
LOW LEVEL JET DEVELOPING OVERHEAD PROVIDES A BIT OF MIXING. THIS
SETUP SHOULD KEEP TEMPS FROM DROPPING VERY FAR...AND MADE LITTLE
CHANGE TO PREVIOUS FORECAST WITH MID-UPPER 20S ALL AREAS. BOTH THE
SREF/NAM VISIBILITY PRODUCTS HINT AT SOME FOG POTENTIAL NEAR THE
EASTERN EDGE OF THE CWA DURING THE NIGHT...BUT WILL LEAVE OUT OF
THE FORECAST AS BELIEVE THE INCREASING BREEZES SHOULD KEEP ANY
FOG FROM AMOUNTING TO MUCH...EVEN IF IT WOULD TRY FORMING.
WEDNESDAY/WEDNESDAY NIGHT...THE PICTURE ALOFT INVOLVES THE CENTRAL
PLAINS REMAINING UNDER QUASI-ZONAL FLOW...AS A PROGRESSIVE...SLOWLY
AMPLIFYING SHORTWAVE TROUGH DRIFTS OUT OF THE NORTHERN ROCKIES
TOWARD THE NORTHERN NEB/IA REGION. AHEAD OF THIS WAVE...A
MILD...DRY AND SOMEWHAT BREEZY DAY IS ANTICIPATED...AS SUSTAINED
SOUTHWEST WINDS 15-20 MPH WITH HIGHER GUSTS PICK UP AHEAD OF AN
ADVANCING SURFACE TROUGH. THESE WIND SPEEDS ARE ROUGHLY 5 MPH
HIGHER THAN PREVIOUS FORECAST. GIVEN THIS GOOD MIXING REGIME AND
SKIES AVERAGING NO WORSE THAN PARTLY CLOUDY...LOOKING AT A
SEASONABLY WARM DAY AND PER SUGGESTION OF VARIOUS MODELS HAVE
RAISED HIGHS 2-3 DEGREES MOST AREAS...PUTTING MOST PLACES
GENERALLY 55-59. PER THE 18Z NAM...SOME WESTERN AREAS COULD EVEN
TOP 60...BUT KEPT THE VAST MAJORITY OF THE AREA BELOW 60 FOR NOW.
BY WED EVENING...THE MAIN SHORTWAVE AXIS ALOFT WILL ENTER THE
LOCAL AREA...WHILE IN THE LOW LEVELS EVIDENT FROM 850MB TO THE
SURFACE...A MODEST COLD FRONT WILL PASS THROUGH. AS THIS LOW LEVEL
BOUNDARY ENCOUNTERS INCREASING MOISTURE...VARIOUS MODELS ARE
CONSISTENT IN BREAKING OUT A CORRIDOR OF RAIN SHOWERS/EMBEDDED
WEAK THUNDERSTORMS ACROSS MUCH OF SOUTHERN/EASTERN KANSAS. WHILE
THE 18Z NAM/12Z GEM KEEP THIS ACTIVITY AT LEAST SLIGHTLY SOUTHEAST
OF OUR CWA...THE LATEST ECWMF/GFS RUNS AT LEAST BRUSH OUR FAR
SOUTHEAST COUNTIES AROUND BELOIT KS. CONTEMPLATED ADDING A SLIGHT
CHANCE OF SHOWERS IN THIS FAR SOUTHEAST AREA...BUT GIVEN THIS IS
STILL 5 FORECAST PERIODS AWAY WILL MAINTAIN OUR PREVIOUSLY DRY
FORECAST AND LET THE NEXT FEW SHIFTS MONITOR THE TRENDS FOR
POSSIBLE INTRODUCTION OF RAIN CHANCES.
THURSDAY/THURSDAY NIGHT...CONFIDENCE IS FAIRLY HIGH IN A DRY 24
HOURS...AS FAIRLY UNEVENTFUL QUASI-ZONAL FLOW IS PRESENT ALOFT
BEHIND THE SHORTWAVE TROUGH FROM WED NIGHT THAT DEPARTS EASTWARD
ACROSS IA DURING THE DAY...AND A MORE SIGNIFICANT SYSTEM JUST
STARTING TO ORGANIZE OVER THE WESTERN CONUS. LOW LEVEL TEMPS WILL
BE A BIT COOLER THAN WED...AND BREEZES WILL BE LIGHTER...WHICH
SHOULD RESULT IN A SLIGHTLY COOLER BUT STILL PLEASANT DAY. MADE
LITTLE CHANGE TO HIGH TEMPS...WITH LOW 50S MOST AREAS.
FRIDAY/FRIDAY NIGHT...THINGS START TO TURN MORE INTERESTING
ALOFT...AS THERE IS FAIRLY GOOD AGREEMENT AMONGST THE 12Z
ECMWF/GFS/GEM THAT A CLOSED 500MB LOW WILL DEVELOP OVER THE DESERT
SOUTHWEST AND BECOME CENTERED NEAR THE NV/AZ/UT BORDER AREA BY
SUNRISE SATURDAY MORNING. CONFIDENCE REMAIN QUITE HIGH IN A DRY
DAYTIME PERIOD AS FORCING REMAINS WELL SOUTHWEST OF THE LOCAL
AREA...WHILE AT THE SURFACE SOUTH BREEZES AVERAGE AT LEAST 15-20
MPH...WITH CURRENT FORECAST SPEEDS POSSIBLE NOT HIGH ENOUGH.
NUDGED UP HIGH TEMPS VERY SLIGHTLY...GETTING ALL BUT FAR EASTERN
COUNTIES TO AT LEAST 50 DEGREES. BY FRIDAY NIGHT...THE GFS SUGGESTS
THAT LOW LEVEL MOISTURE COULD INCREASE ENOUGH FOR POSSIBLE DRIZZLE
DEVELOPMENT...BUT WITH THIS BEING SEVERAL DAYS AWAY AND LIKELY NOT
A MEASURABLE PRECIP RISK...WILL LEAVE OUT ANY MENTION.
AS ALREADY MENTIONED...THE 36-HOUR TIME FRAME BETWEEN SATURDAY AND
SUNDAY NIGHT HOLDS PLENTY OF POTENTIAL TO BE VERY INTERESTING IN
SEVERAL POSSIBLE WAYS INCLUDING ACCUMULATING SNOW...THUNDERSTORMS
AND STRONG GRADIENT WINDS THAT COULD RESULT IN BLOWING SNOW.
HOWEVER...THERE IS STILL A WHOLE LOT TO HAMMER OUT STILL BEING 5-6
DAYS AWAY...SO FOR NOW HAVE ONLY INTRODUCED SOME STANDARD
ACCUMULATING SNOW POSSIBLE/UNCERTAINTY HIGH WORDING INTO THE
HAZARDOUS WEATHER OUTLOOK...AND HAVE REFRAINED FROM INTRODUCING
THUNDERSTORMS YET. IN SHORT...THE 12Z ECMWF/GEM ARE IN PRETTY GOOD
AGREEMENT MAINTAINING THIS SYSTEM AS A COMPACT...POWERFUL CLOSED
LOW THAT COULD HAVE SOME LOCAL IMPACTS...WHILE THE GFS DEPICTS A
MUCH MORE ELONGATED/LESS-FOCUSED UPPER SYSTEM WITH AT MOST ONLY A
MINOR/NUISANCE WINTRY SIDE. HAVE CAPPED POPS AT 50 PERCENT RANGE
FOR NOW...AS ITS STILL TOO EARLY TO SAY ANYTHING IS 60+ PERCENT
LIKELY AT ANY GIVEN SPOT. FOCUSING ON WHAT CONFIDENCE IS
RELATIVELY HIGH IN...ANY PRECIP THAT BREAKS OUT DAYTIME SATURDAY
SHOULD STAY IN LIQUID/SHOWERY FORM. THEN SATURDAY NIGHT...THE
ECWMF/GEM SOLUTIONS AGREE ON A FAIRLY VERTICALLY STACKED...STRONG
LOW PRESSURE SYSTEM CENTERED ALONG THE KS/CO BORDER BY SUNRISE
SUNDAY MORNING...ALTHOUGH THE ECMWF KEEPS WARMER AIR ALOFT IN
PLACE THROUGH THE NIGHT INSTEAD OF CHANGING OVER TO SNOW IN
NORTHWEST COUNTIES. AS A RESULT...HAVE MOVED THE RAIN/SNOW
TRANSITION LINE FARTHER NORTHWEST COMPARED TO PREVIOUS FORECAST.
THEN FOR SUNDAY/SUNDAY NIGHT...TH LATEST ECWMF SOLUTION TAKES THE
TRACK OF THE MID LEVEL CLOSED LOW DIRECTLY OVER THE HEART OF THE
CWA...WHICH WOULD IN THEORY FOCUS THE BEST ACCUMULATING SNOW
POTENTIAL ACROSS OUR NORTHWEST 1/2...AND MAYBE KEEP SHOWERS/STORMS
GOING IN SOUTHEAST AREAS DURING THE DAY BEFORE COLDER AIR FILTERS
IN DURING THE EVENING. PLENTY OF CHANGES ARE LIKELY IN THE DETAILS
OVER THE COMING DAYS...AND WANT TO EMPHASIZE THAT ITS STILL TOO
EARLY TO GET OVERLY CONCERNED.
GETTING BEYOND THIS POTENTIAL WEATHER-MAKER INTO MONDAY...EVEN THE
SLOWER ECMWF SOLUTION PULLS ALL PRECIP RISK AT LEAST SLIGHTLY EAST
OF THE CWA...SO WILL ADVERTISE A DRY DAY. CONFIDENCE IN HIGH TEMPS
IS QUITE LOW DEPENDING ON HOW THE WEEKEND SHAKES OUT...SO SIMPLY
WENT WITH ALLBLEND MODEL SOLUTION OF MID 30S MOST NEB ZONES...AND
NEAR 40 IN KS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
305 PM CST TUE FEB 5 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...
THE HIGHLIGHT OF THE SHORT TERM FORECAST IS FOG TONIGHT AND SNOW
INTO WEDNESDAY. THE 12 UTC GUIDANCE SUITE IS GOOD AGREEMENT...AND
WILL UTILIZE A BLEND FOR MOST FORECAST FIELDS.
AS OF 21 UTC...THE SURFACE BOUNDARY THAT HAS BISECTED WESTERN AND
CENTRAL NORTH DAKOTA FOR SEVERAL DAYS WAS LOCATED FROM BETWEEN
MINOT AND STANLEY...THROUGH HAZEN AND BISMARCK INTO NORTH CENTRAL
SOUTH DAKOTA. DID ADD A MENTION OF PATCHY FOG GENERALLY FOR
LOCATIONS ALONG AND IN BETWEEN THE HIGHWAY 83 AND 85 CORRIDORS
WHERE NEAR TO ABOVE FREEZING TEMPERATURES HAVE ADDED BOUNDARY
LAYER MOISTURE FROM SNOW MELT...WITH RATHER LIGHT WINDS EXPECTED
THROUGH MUCH OF THE NIGHT. DID TRIM THE FOG BACK ACROSS THE WEST
THROUGH THE NIGHT AS MIXING INCREASES AS THE AFOREMENTIONED
BOUNDARY PROPAGATES EAST ONCE AGAIN AS A WARM FRONT. ON THE COOL
SIDE OF THIS BOUNDARY...DID MAINTAIN THE FLURRY MENTION UNDERNEATH
THE STRATUS THAT SHOULD REMAIN IN PLACE THROUGH MUCH OF THE NIGHT
GIVEN THE LATEST RUNS OF THE HRRR AND RAP.
PRECIPITATION SHOULD SLOWLY DEVELOP THROUGH THE NIGHT NORTH AS
ISENTROPIC LIFT INCREASES AND FOCUSES ACROSS NORTHERN NORTH DAKOTA
IN ASSOCIATION WITH THE WARM FRONT. THE PREDOMINANT PRECIPITATION
TYPE IS EXPECTED TO BE SNOW. HOWEVER...CANNOT RULE OUT SOME SLEET
MIXING IN NORTHWEST WITH A WEAK WARM LAYER ALOFT CAPABLE OF
PARTIAL MELTING. ISENTROPIC LIFT CONTINUES ACROSS THE NORTH CENTRAL
THROUGH WEDNESDAY...WITH THE GREATEST SNOWFALL ACCUMULATIONS OF
ONE TO TWO INCHES EXPECTED ACROSS THE TURTLE MOUNTAINS.
A SIMILIAR TEMPERATURE PATTERN IS FORECAST ON WEDNESDAY WITH HIGHS
IN THE 40S ACROSS THE SOUTHWEST AND UPPER 30S SOUTH CENTRAL BEHIND
THE WARM FRONT...TO THE TEENS ACROSS THE FAR NORTH CENTRAL ON THE
FRINGE OF THE ARCTIC AIR. DID PREFER BIAS CORRECTION WHICH HAS
SHOWN GOOD VERIFICATION OVER THE PAST FEW DAYS IN A SIMILIAR
ENVIRONMENT...WITH THE CORRECTION BEING AN INCREASE OF 2-4
DEGREES...ESPECIALLY ACROSS THE SOUTHWEST. FOG WILL ONCE AGAIN BE
POSSIBLE FROM SNOWMELT ON WEDNESDAY NIGHT AS COOLER AIR ADVECTS
ACROSS THE AREA WITH A TRAILING COLD FRONT WITH WINDS BECOMING
LIGHT IN A WEAK SURFACE RIDGE AXIS.
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
FORECAST HIGHLIGHTS IN THE LONG TERM PERIOD WILL BE ABOVE NORMAL
TEMPERATURES THROUGH THE WORK WEEK...A COOL DOWN TO NEAR NORMAL
HIGH/LOW TEMPERATURES FOR THIS COMING WEEKEND/EARLY NEXT WEEK...AND
CHANCES FOR SNOW SATURDAY NIGHT-SUNDAY-SUNDAY NIGHT.
WEAK UPPER LEVEL RIDGE OVER THE WESTERN CONUS WEDNESDAY BUILDS EAST
INTO THE NORTHERN PLAINS THURSDAY/FRIDAY...BRINGING DRY CONDITIONS
AND CONTINUED ABOVE NORMAL TEMPERATURES THROUGH THE REMAINDER OF THE
WORK WEEK.
UPPER TROUGH OVER THE WEST COAST THURSDAY...DEVELOPS INTO A SPLIT
FLOW PATTERN FRIDAY WITH A LARGE CLOSED LOW DEVELOPING OVER THE
DESERT SOUTHWEST AND THE NORTHERN STREAM WELL TO OUR NORTH OVER
CENTRAL CANADA. THE UPPER LOW IS FORECAST TO LIFT NORTH AND EAST
THROUGH THE CENTRAL PLAINS AND INTO THE UPPER MISSISSIPPI VALLEY
REGION OVER THE COMING WEEKEND...WITH A NORTHERN STREAM S/WV DIVING
SOUTHEAST OUT OF THE ALBERTA ROCKIES AND INTO THE NORTHERN PLAINS.
AT THIS TIME THE BULK OF THE PRECIPITATION ASSOCIATED WITH THE
SOUTHERN STREAM LOW IS STILL DEPICTED BY ALL MODELS TO STAY SOUTH
AND EAST OF WEST/CENTRAL NORTH DAKOTA. HOWEVER...LATEST ECMWF DOES
INDICATE A SLIGHT WESTWARD SHIFT OF THE HEAVY PRECIP BAND NOW INTO
FAR SOUTHEASTERN NORTH DAKOTA. THIS WILL NEED TO BE MONITORED OVER
THE COMING DAYS IN CASE OF ANY ADDITIONAL WESTWARD SHIFTS. HAVE
INTRODUCED SLIGHT CHANCES FOR SNOW AREA WIDE SATURDAY NIGHT THROUGH
SUNDAY NIGHT AS THE ALBERTA S/WV MOVES INTO THE LOCAL AREA...ALONG
WITH WRAP AROUND PRECIPITATION ASSOCIATED WITH THE SOUTHERN STREAM
UPPER LOW. IF MODELS MAINTAIN THEIR RECENT TREND...POPS WILL NEED TO
BE INCREASED. CONFIDENCE IS HIGHER THAT TEMPERATURES WILL TREND
COOLER FOR THE WEEKEND AS COLDER AIR IS PULLED SOUTH FROM CANADA
INTO NORTH DAKOTA AS BOTH SYSTEMS MERGE. IN COLLABORATION WITH
SURROUNDING OFFICES...WENT WELL BELOW THE ALLBLEND FOR TEMPERATURES
THROUGH THE LATER PARTS OF THE WEEKEND AND INTO MONDAY...ESPECIALLY
FOR THE SUNDAY MAXT AND SUNDAY NIGHT MINT PERIODS. WINDS WERE ALSO
SIGNIFICANTLY INCREASED FROM THE ALLBLEND SUNDAY INTO MONDAY.
&&
.AVIATION...
MVFR CIGS WILL CONTINUE THROUGH 22-01Z FOR KMOT-KJMS. CIGS SHOULD
SCATTER OUT FOR KMOT LATE AFTERNOON/EARLY EVENING. VFR CONDITIONS
EXPECTED AREA WIDE BY MID-EVENING...THE ONLY EXCEPTION COULD BE KJMS.
LOW PRESSURE MOVING INTO THE REGION TONIGHT WITH INCREASING VFR
CLOUDS WEST TO EAST THIS EVENING. A BAND OF MIXED PRECIPITATION IS
EXPECTED TO DEVELOP INTO NORTHERN NORTH DAKOTA LATE
TONIGHT...SPREADING EAST AND SLIGHTLY SOUTH THROUGH WEDNESDAY
MORNING. SNOW...FREEZING RAIN...AND SLEET WILL ALL BE POSSIBLE
IMPACTING KISN-KMOT-KBIS-KJMS ALONG WITH SCATTERED MVFR CIGS. IFR
VIS POSSIBLE NORTH...KMOT...WHERE MAINLY SNOW IS EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM/AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
715 PM EST WED FEB 6 2013
.SYNOPSIS...
ALTHOUGH THE CENTER OF HIGH PRESSURE WILL SLIDE EAST OF THE REGION
TONIGHT...IT WILL CONTROL THE REGIONS WEATHER INTO TOMORROW. A
COLD FRONT WILL MOVE ACROSS THE REGION THURSDAY NIGHT AND EARLY
FRIDAY...BRINGING AN AREA RAIN...BEFORE COLDER AIR CHANGES IT TO
SOME SNOW. HIGH PRESSURE WILL MOVE IN AGAIN FOR FRIDAY NIGHT AND
SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AREA OF STUBBORN CLOUDS ACROSS THE SRN PORTION OF THE FA CONTINUES
TO SLOWLY ERODE FROM THE N AND S. LATEST RUC MODEL RUN SUGGESTS THAT
THESE CLOUDS WILL CONTINUE TO DISSIPATE AND SHOULD BE GONE SHORTLY
AFTER MIDNIGHT. MEANWHILE MIDDLE TO HIGH CLOUDS WILL WORK ACROSS
THE REGION TONIGHT...BRINGING PARTLY CLOUDY SKIES TO THE REGION.
THE COMBINATION OF THE LOW CLOUDS EARLY AND THE HIGHER CLOUDS
LATER IN THE NIGHT WILL HELP KEEP THE TEMPERATURES UP A LITTLE.
WENT CLOSE TO MOS GUIDANCE IN THE S...BUT A LITTLE COOLER IN THE
N...WITH THE CLOUD COVER AND ALREADY CLEAR SKIES. LOWS SHOULD
RANGE FROM THE UPPER 20S IN THE S TO UPPER TEENS IN THE EXTREME
RURAL NE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
FA WILL BE UNDER WAA ON THURSDAY. MODELS HAVE SLOWED THE EWD
PROGRESSION OF THE DEVELOPING SFC AND CDFNT. THUS HAVE DRIED OUT
THURSDAY. GFS MOS REMAINS THE COLDEST. THIS COULD BE IN RESPONSE
TO THE SNOW COVER ACROSS THE N. WENT WITH A BLEND OF THE
GUIDANCE...THIS PUTS VALUES IN THE N A FEW DEGREES WARMER THAN
THE COLD GFS MOS IN THE NW...BUT CLOSE ELSEWHERE.
THE NAM IS THE OUTLIER WITH THE SYSTEM FOR THURSDAY NIGHT/FRIDAY. IT
IS QUICKER WITH THE SFC FEATURE AND WEAKER WITH THE TRAILING H5
S/W. THE GFS/ECMWF AND CMC ALL SWING THE STRONGER S/W IN AFTER
12Z FRI...WHICH SHOULD PROVIDE LIFT FOR LINGERING SHOWERS...SNOW
IN THE N AND A RA/SN MIX IN THE S. SO KEPT THE 100 POPS THURSDAY
NIGHT WITH FRONT IN THE WAA AND LINGERED PCPN MAINLY FRI MORNING.
WENT WITH A GFS/ECMWF BLEND ON THE THICKNESSES FOR THE CHANGE OVER
TO SNOW...SO WENT TO SNOW QUICKLY FRIDAY MORNING IN THE NW...BUT
WAITED UNTIL AFTERNOON FOR THE SRN LOCATIONS. HIGH PRESSURE BUILDS
BACK IN FOR FRIDAY NIGHT.
HIGHS IN THE NW COULD BE EARLY FRIDAY IN THE NW...WITH MORE SRN
LOCATIONS MAYBE SEEING HIGHS AROUND NOON INSTEAD OF LATE
AFTERNOON. WITH GRADUALLY CLEARING SKIES FRIDAY NIGHT
TEMPERATURES WILL FALL INTO THE UPPER TEENS TO LOWER 20S FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY STARTS OUT DRY WITH HIGH PRESSURE AT THE SURFACE AND AN
INCOMING UPPER LEVEL RIDGE. THE RIDGE CROSSES THE OHIO VALLEY
OVERNIGHT AND THERE IS A MARKED INCREASE IN MOISTURE ON THE BACK
SIDE OF IT BY DAYBREAK SUNDAY. HAVE PULLED BACK ON THE SLIGHT CHANCE
OF SHOWERS WORKING IN EARLY IN THE DAY AS MODELS ARE BARELY SHOWING
THE ONSET OF RAIN IN SOUTHWEST INDIANA BY 12Z AND THE SURFACE TEMPS
ARE QUITE COLD. PULLING THE CHANCE FOR PRECIP OUT AT THIS TIME
REMOVES THE POTENTIAL FOR THE RAIN TO NEED A FREEZING QUALIFIER IN
THE FORECAST.
KEPT A LIKELY CHANCE OF RAIN WITH THE FRONTAL PASSAGE ON SUNDAY.
LEFTOVER COLD FRONT FROM SUNDAY NIGHT/MONDAY SYSTEM OVER THE TN
VALLEY IS NOW BEING PROGGED TO REMAIN SOUTH OF THE APPALACHIANS WITH
HIGH PRESSURE OVER THE OHIO VALLEY. FORECAST SHOWS LARGER VARIANCES
WITH A LOW TRACKING INTO THE OHIO VALLEY FROM THE SOUTHWEST ON
WEDNESDAY AND SOME POPS WERE WARRANTED WITH THIS POTENTIAL SYSTEM.
A WARMUP WILL OCCUR OVERNIGHT SATURDAY AND TEMPERATURES FROM SUNDAY
THROUGH TUESDAY WILL REMAIN ABOVE FREEZING. WITH THE UNCERTAINTY ON
THE EVOLUTION OF THE WEDNESDAY SYSTEM...THREW IN SNOW WHERE TEMPS
WERE BELOW FREEZING TO START THE DAY WITH...THOUGH IT APPEARS THAT
IF PRECIP OCCURS IT WILL BE WITH A WARM FRONT AND MORE OF A
RAIN/FREEZING RAIN THAN SNOW.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
MVFR CIGS ACROSS PORTIONS OF THE AREA AT THE START OF THE TAF
PERIOD WILL DISSIPATE WITHIN A FEW HOURS. SOME MVFR VSBYS WILL BE
POSSIBLE HOWEVER FOR A PERIOD OVERNIGHT AT KCVG...KLUK...AND KILN.
VFR CONDITIONS WILL RETURN AT ALL TAF SITES DURING THE DAYTIME
MORNING HOURS ON THURSDAY. MID AND HIGH CLOUDS WILL MOVE INTO THE
TAF SITES OVERNIGHT AND REMAIN ACROSS THE REGION THROUGH THE DAY
ON THURSDAY.
OUTLOOK...MVFR CEILINGS LIKELY LATE THURSDAY NIGHT INTO FRIDAY
WITH MVFR VISIBILITIES POSSIBLE. MVFR CEILINGS AND VISIBILITY
POSSIBLE AGAIN SUNDAY NIGHT INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...SITES
NEAR TERM...SITES
SHORT TERM...SITES
LONG TERM...FRANKS
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS NORMAN OK
1144 AM CST TUE FEB 5 2013
.DISCUSSION...
18Z AVIATION DISCUSSION FOLLOWS....
&&
.AVIATION...
A LARGE AREA OF LOW-LEVEL MOISTURE WILL HAVE A MAJOR IMPACT ON TAF
SITES OVER THE NEXT 24 HOURS. WHILE THE OUTER EDGE OF THE CLOUD
AREA WILL CONTINUE TO ERODE THIS AFTERNOON...INDICATIONS ARE THAT
CLOUDS AND FOG WILL REDEVELOP QUICKLY THIS EVENING...BEGINNING
MAINLY NEAR THE CURRENT NW EDGE OF THE CLOUD AREA. AS LOW-LEVEL
FLOW BECOMES SE TOMORROW MORNING...THE MOISTURE AREA WILL BEGIN TO
SHIFT NW...COVERING ALL OF OUR FORECAST AREA BY ABOUT MID-MORNING.
CLEAR SKIES ABOVE WILL LIKELY ENHANCE THE REDEVELOPMENT OF BOTH
FOG AND LOW CLOUDS THIS EVENING/OVERNIGHT. ADVECTION FOG IS QUITE
POSSIBLE ACROSS W AND N OK TOMORROW AS HIGH-DEWPOINT AIR IS DRAWN
INTO AREAS THAT MAY GET A CHANCE TO COOL OFF OVERNIGHT...TO
TEMPERATURES BELOW THE DEW POINTS OF THE INCOMING AIRMASS.
&&
.PREV DISCUSSION... /ISSUED 555 AM CST TUE FEB 5 2013/
AVIATION...
LOW CLOUDS AND FOG WILL BE A CONCERN THIS MORNING
AT SPS/LAW/OUN AND PERHAPS OKC. WESTERN EDGE OF
LOW CLOUDS AND FOG EXTEND FROM SPS TO DUNCAN NEAR CHICKASHA
AND MAY DEVELOP OVER OUN/LAW BY 13Z. ANY CLOUDS THAT FORM
SHOULD CLEAR BY 16-17Z. LOW CLOUDS AND SOME FOG
SHOULD REDEVELOP OVERNIGHT TONIGHT. WILL MENTION MVFR
CEILINGS AT TERMINAL SITES ALONG AND SOUTH OF I-40.
PREV DISCUSSION... /ISSUED 414 AM CST TUE FEB 5 2013/
DISCUSSION...
LOW CLOUDS AND DENSE FOG WILL BE MAIN WEATHER IMPACT
TODAY/THIS MORNING. HRRR RUNS HAVE LOW CLOUDS AND
FOG DEVELOPING TO A WICHITA FALLS...NORMAN AND TULSA
LINE AFTER SUNRISE THIS MORNING AND SLOWLY ERODE CLOUDS
DURING THE MORNING/EARLY AFTERNOON. THIS MAY BE A LITTLE
FAR NORTH AND WEST BASED ON RECENT SATELLITE TRENDS.
DID ISSUE A DENSE FOG ADVISORY FOR SEVERAL SOUTH CENTRAL
AND SOUTHEAST COUNTIES MAINLY FOR RAPIDLY CHANGING
CONDITIONS THAT HAVE BEEN REPORTED.
BETTER CHANCE OF LOW CLOUDS AND FOG DEVELOPING OVERNIGHT
TUESDAY INTO WEDNESDAY MORNING WITH INCREASING EAST TO
SOUTHEAST FLOW. DID ADJUST TEMPS AND DEWPOINT UP MOST AREAS
TONIGHT INTO WEDNESDAY.
FEATURE OVER BAJA THIS MORNING WILL MOVE EAST TODAY INTO
TONIGHT. EC MODEL AND NAM12 BOTH DEVELOP SOME PRECIP ACROSS
SOUTHEAST OKLAHOMA WEDNESDAY AS THIS WAVE MOVES EAST
AND WEAKENS.
BETTER CHANCE FOR RAIN/STORMS WILL ARRIVE LATE WEDNESDAY INTO
THURSDAY AS A FRONT AND UPPER WAVE MOVE ACROSS THE AREA. AIR
MASS AHEAD OF THE FRONT WILL BE RATHER WARM AND MOIST FOR
EARLY FEBRUARY. STILL APPEARS BETTER CHANCES FOR DECENT
RAIN WILL BE ACROSS EASTERN HALF OF THE FA.
STILL SOME UNCERTAINTIES WITH THE DEVELOPMENT OF A TROUGH/LOW
LATE THIS WEEK INTO THE WEEKEND. FOR NOW WILL FOLLOW CLOSER
TO THE EC MODEL WHICH BRINGS BEST CHANCE FOR RAIN/STORMS SATURDAY
INTO FIRST HALF OF SUNDAY. MOST AREAS SHOULD RECEIVE BENEFICIAL
RAINFALL WITH THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 43 66 54 / 0 0 0 40
HOBART OK 67 42 68 50 / 0 0 10 30
WICHITA FALLS TX 70 50 71 54 / 0 0 0 30
GAGE OK 63 34 69 40 / 0 0 0 30
PONCA CITY OK 64 38 66 48 / 0 0 0 50
DURANT OK 68 50 68 53 / 0 0 20 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/23/23
AREA FORECAST DISCUSSION
NWS NORMAN OK
555 AM CST TUE FEB 5 2013
.AVIATION...
LOW CLOUDS AND FOG WILL BE A CONCERN THIS MORNING
AT SPS/LAW/OUN AND PERHAPS OKC. WESTERN EDGE OF
LOW CLOUDS AND FOG EXTEND FROM SPS TO DUNCAN NEAR CHICKASHA
AND MAY DEVELOP OVER OUN/LAW BY 13Z. ANY CLOUDS THAT FORM
SHOULD CLEAR BY 16-17Z. LOW CLOUDS AND SOME FOG
SHOULD REDEVELOP OVERNIGHT TONIGHT. WILL MENTION MVFR
CEILINGS AT TERMINAL SITES ALONG AND SOUTH OF I-40.
&&
.PREV DISCUSSION... /ISSUED 414 AM CST TUE FEB 5 2013/
DISCUSSION...
LOW CLOUDS AND DENSE FOG WILL BE MAIN WEATHER IMPACT
TODAY/THIS MORNING. HRRR RUNS HAVE LOW CLOUDS AND
FOG DEVELOPING TO A WICHITA FALLS...NORMAN AND TULSA
LINE AFTER SUNRISE THIS MORNING AND SLOWLY ERODE CLOUDS
DURING THE MORNING/EARLY AFTERNOON. THIS MAY BE A LITTLE
FAR NORTH AND WEST BASED ON RECENT SATELLITE TRENDS.
DID ISSUE A DENSE FOG ADVISORY FOR SEVERAL SOUTH CENTRAL
AND SOUTHEAST COUNTIES MAINLY FOR RAPIDLY CHANGING
CONDITIONS THAT HAVE BEEN REPORTED.
BETTER CHANCE OF LOW CLOUDS AND FOG DEVELOPING OVERNIGHT
TUESDAY INTO WEDNESDAY MORNING WITH INCREASING EAST TO
SOUTHEAST FLOW. DID ADJUST TEMPS AND DEWPOINT UP MOST AREAS
TONIGHT INTO WEDNESDAY.
FEATURE OVER BAJA THIS MORNING WILL MOVE EAST TODAY INTO
TONIGHT. EC MODEL AND NAM12 BOTH DEVELOP SOME PRECIP ACROSS
SOUTHEAST OKLAHOMA WEDNESDAY AS THIS WAVE MOVES EAST
AND WEAKENS.
BETTER CHANCE FOR RAIN/STORMS WILL ARRIVE LATE WEDNESDAY INTO
THURSDAY AS A FRONT AND UPPER WAVE MOVE ACROSS THE AREA. AIR
MASS AHEAD OF THE FRONT WILL BE RATHER WARM AND MOIST FOR
EARLY FEBRUARY. STILL APPEARS BETTER CHANCES FOR DECENT
RAIN WILL BE ACROSS EASTERN HALF OF THE FA.
STILL SOME UNCERTAINTIES WITH THE DEVELOPMENT OF A TROUGH/LOW
LATE THIS WEEK INTO THE WEEKEND. FOR NOW WILL FOLLOW CLOSER
TO THE EC MODEL WHICH BRINGS BEST CHANCE FOR RAIN/STORMS SATURDAY
INTO FIRST HALF OF SUNDAY. MOST AREAS SHOULD RECEIVE BENEFICIAL
RAINFALL WITH THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 43 66 54 / 0 0 0 40
HOBART OK 67 42 68 50 / 0 0 10 30
WICHITA FALLS TX 70 50 71 54 / 0 0 0 30
GAGE OK 63 34 69 40 / 0 0 0 30
PONCA CITY OK 64 38 66 48 / 0 0 0 50
DURANT OK 68 50 68 53 / 10 0 20 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR OKZ032-
039>043-045>048-050>052.
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ090.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
414 AM CST TUE FEB 5 2013
.DISCUSSION...
LOW CLOUDS AND DENSE FOG WILL BE MAIN WEATHER IMPACT
TODAY/THIS MORNING. HRRR RUNS HAVE LOW CLOUDS AND
FOG DEVELOPING TO A WICHITA FALLS...NORMAN AND TULSA
LINE AFTER SUNRISE THIS MORNING AND SLOWLY ERODE CLOUDS
DURING THE MORNING/EARLY AFTERNOON. THIS MAY BE A LITTLE
FAR NORTH AND WEST BASED ON RECENT SATELLITE TRENDS.
DID ISSUE A DENSE FOG ADVISORY FOR SEVERAL SOUTH CENTRAL
AND SOUTHEAST COUNTIES MAINLY FOR RAPIDLY CHANGING
CONDITIONS THAT HAVE BEEN REPORTED.
BETTER CHANCE OF LOW CLOUDS AND FOG DEVELOPING OVERNIGHT
TUESDAY INTO WEDNESDAY MORNING WITH INCREASING EAST TO
SOUTHEAST FLOW. DID ADJUST TEMPS AND DEWPOINT UP MOST AREAS
TONIGHT INTO WEDNESDAY.
FEATURE OVER BAJA THIS MORNING WILL MOVE EAST TODAY INTO
TONIGHT. EC MODEL AND NAM12 BOTH DEVELOP SOME PRECIP ACROSS
SOUTHEAST OKLAHOMA WEDNESDAY AS THIS WAVE MOVES EAST
AND WEAKENS.
BETTER CHANCE FOR RAIN/STORMS WILL ARRIVE LATE WEDNESDAY INTO
THURSDAY AS A FRONT AND UPPER WAVE MOVE ACROSS THE AREA. AIR
MASS AHEAD OF THE FRONT WILL BE RATHER WARM AND MOIST FOR
EARLY FEBRUARY. STILL APPEARS BETTER CHANCES FOR DECENT
RAIN WILL BE ACROSS EASTERN HALF OF THE FA.
STILL SOME UNCERTAINTIES WITH THE DEVELOPMENT OF A TROUGH/LOW
LATE THIS WEEK INTO THE WEEKEND. FOR NOW WILL FOLLOW CLOSER
TO THE EC MODEL WHICH BRINGS BEST CHANCE FOR RAIN/STORMS SATURDAY
INTO FIRST HALF OF SUNDAY. MOST AREAS SHOULD RECEIVE BENEFICIAL
RAINFALL WITH THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 43 66 54 / 0 0 0 40
HOBART OK 67 42 68 50 / 0 0 10 30
WICHITA FALLS TX 70 50 71 54 / 0 0 0 30
GAGE OK 63 34 69 40 / 0 0 0 30
PONCA CITY OK 64 38 66 48 / 0 0 0 50
DURANT OK 68 50 68 53 / 10 0 20 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR OKZ032-
039>043-045>048-050>052.
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ090.
&&
$$
17/6
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
435 PM MST WED FEB 6 2013
.UPDATE...12Z UNR WRF/LATEST RAP SHOWED A SMALL AREA OF CONVECTIVE
-SHRASN OVER FAR SOUTHWEST SD INTO A SMALL PORTION OF SOUTH
CENTRAL SD. THIS MATCHES LATEST KUDX RADAR TRENDS...SO WILL ADD
SOME ISOLATED -SHRASN TO THE FORECAST FOR EARLY THIS EVENING.
&&
.AVIATION...00Z TAFS
MAINLY VFR CONDITIONS EXPECTED THROUGH THURSDAY. EARLY THIS
EVENING...LOCAL MVFR CIGS/VSBYS EXPECTED OVER FAR SOUTHWEST SD AS
SOME CONVECTIVE -SHRASN MOVE OFF THE BLACK HILLS.
&&
.PREV DISCUSSION... /ISSUED 302 PM MST WED FEB 6 2013/
DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS WEAK LOW PRESSURE OVER
CENTRAL ND...WITH A SURFACE TROF STRETCHING SOUTHWARD ACROSS
CENTRAL SD. UPPER LEVEL ANALYSIS SHOWS WEAK SHORTWAVE MOVING
ACROSS THE NORTHERN HIGH PLAINS...WITH A RIDGE BUILDING OVER THE
PACIFIC NW...AND A LOW OFF THE PACIFIC COAST. SKIES ARE PARTLY
SUNNY ACROSS MUCH OF THE AREA. REGIONAL RADARS NOT SHOWING MUCH IN
THE WAY OF ECHO RETURNS...EXCEPT FOR SOME WEAK RETURNS OVER THE
HIGHER TERRAIN OF WY AND THE BLACK HILLS. WITH ONLY WEAK LIFT AND
LIMITED LOW LEVEL MOISTURE IN PLACE...NOT EXPECTING MUCH MORE
THAN A FEW SPRINKLES/FLURRIES ACROSS THE BLACK HILLS THROUGH THE
AFTERNOON. TEMPS ARE CURRENTLY IN THE 40S AND LOWER 50S AT MOST
LOCATIONS. NORTHWESTERLY WINDS REMAIN BREEZY TO WINDY ACROSS
PORTIONS OF WESTERN SD...MAINLY FROM THE 2WX TO RAP CORRIDOR.
MILD WEATHER WILL CONTINUE THROUGH FRIDAY AS AN UPPER LEVEL RIDGE
SLIDES EAST ACROSS THE ROCKIES AND NORTHERN PLAINS. UPPER LOW OFF
THE PACIFIC NW COAST WILL MOVE SOUTHEAST INTO THE SOUTHWESTERN
CONUS LATE THIS WEEK...AND THEN TRACK ACROSS THE CENTRAL ROCKIES
AND PLAINS OVER THE WEEKEND. THE TRACK OF THE SYSTEM IS STILL
UNCERTAIN AT THIS POINT...BUT SOUTHERN PORTIONS OF THE CWA WILL
SEE THE BEST CHANCES FOR SNOW AND SOME ACCUMULATION...ESPECIALLY
ACROSS FAR SOUTHWESTERN INTO SOUTH CENTRAL SD.
FOR TONIGHT...SKIES WILL CLEAR OUT IN THE EVENING AS SHORTWAVE
MOVES EAST OF THE AREA. WINDS WILL ALSO DIMINISH AFTER SUNSET.
LOWS WILL MOSTLY BE IN THE 20S...WITH SOME TEENS IN THE USUAL
COLDER SPOTS. THE RIDGE WILL BUILD ACROSS THE AREA THURSDAY INTO
FRIDAY...WITH MOSTLY CLEAR SKIES AND MILD CONDITIONS PERSISTING.
THE WARMEST CONDITIONS WILL GENERALLY BE ACROSS WESTERN AND
CENTRAL AREAS ON THURSDAY AND ACROSS EASTERN AREAS ON FRIDAY.
BRISK SOUTHWESTERLY WINDS WILL DEVELOP LATE ON THURSDAY ACROSS
NORTHEASTERN WY AND THE NORTHERN BLACK HILLS AREA...PERSISTING
THROUGH THURSDAY NIGHT. SOME WIND GUSTS TO 40 MPH LOOK LIKELY
ACROSS FAVORED AREAS OF THE NORTHERN BLACK HILLS AND NORTHERN
FOOTHILLS.
AS THE RIDGE MOVES EAST BY FRIDAY NIGHT AND UPPER LOW MOVES INTO
THE CENTRAL ROCKIES...SOUTHWEST FLOW ALOFT WILL DEVELOP OVER THE
HIGH PLAINS. SHORTWAVE ENERGY IN THE FLOW AHEAD OF THE LOW WILL
TRACK ACROSS EASTERN WY OVERNIGHT. CLOUDS WILL INCREASE ACROSS THE
AREA...BUT LOW LEVEL MOISTURE WILL BE SLOW TO RETURN. THE SYSTEM
ALSO LOOKS TO BE A BIT SLOWER AS IT MOVES ACROSS THE ROCKIES. WILL
KEEP SOME LOW POPS FOR SNOW ACROSS SOUTHWESTERN PORTIONS OF
NORTHEASTERN WY AND DRY ELSEWHERE.
EXTENDED...POTENT EJECTING SW CONUS DISTURBANCE WILL SUPPORT A
STRONG WINTER STORM SYSTEM ACROSS THE CENTRAL AND NORTHERN PLAINS AT
THE START OF THE PERIOD...BRINGING WIND AND SNOW TO PORTIONS OF THE
FA. FORECAST MODELS HAVE COME TO CLOSE CONSENSUS PER THE
TRACK/STRENGTH/AND TIMING OF THIS SYSTEM...WITH AT LEAST
SEMI-NORTHERN STREAM FLOW PHASING STILL SUGGESTED IN ALL
DETERMINISTIC GUIDANCE. BRIEF BLOCKING PER THE EXPECTED WOUND UP SFC
CYCLONE AND ASSOCIATED UPPER LEVEL CLOSED LOW WILL LEAD TO A BRIEF
COOL DOWN THE EARLY PART OF NEXT WEEK AS LONG TRAJECTORY NORTHERLY
FLOW RESULTS OVER THE REGION. HOWEVER...SPLIT FLOW WILL QUICKLY
RETURN WITH WESTERN NOAM RIDGING SPILLING OVER INTO THE WESTERN
NORTHERN PLAINS BY EARLY NEXT WEEK...SLIGHTLY SLOWER THAN WHAT
PREVIOUS MODEL SOLUTIONS WHERE INDICATING. NO MAJOR CHANGES MADE TO
THE PREVIOUS FORECAST OTHER THAN CONTINUED THE TREND OF RAISING POPS
OVER SCENTRAL SD PER THIS WEEKEND/S STORM SYSTEM...DUE TO INCREASED
CONFIDENCE PER THIS SYSTEM/S TRACK GIVEN GROWING AGREEMENT PER
DETERMINISTIC MODELS. ANALYSIS OF FGEN/WAA/MID LAPSE RATES SUGGEST A
RATHER STRONG DEFORMATION ZONE WILL FORM OVER NORTHERN NE INTO
SD...WITH A PERIOD OF HEAVY SNOW LIKELY ESP GIVEN THE DEVELOPING
GOMEX CONNECTION INDICATED IN H85 THETA-E PROGS. THE EXACT TRACK OF
THE HEAVIEST SNOW IS STILL IN QUESTION...BUT CURRENT CONSENSUS
INDICATIONS SUGGEST INVOF TODD/MELLETTE/AND TRIPP COUNTIES AND
EAST...WHERE THE POTENTIAL FOR 4 TO 6 INCHES EXISTS. IN
ADDITION...VERY STRONG N/NW WINDS WOULD LIKELY CREATE AREAS OF
BLOWING AND DRIFTING SNOW...WITH SIG VIS REDUCTION. WILL FRESHEN THE
HWO FOR THIS CONCERN. THE REMAINDER OF THE FA WILL SEE MUCH LOWER
CHANCES FOR PRECIP WITH ACCUMS GENERALLY 2 INCHES TO A
DUSTING...SAVE THE NORTHERN BH WHERE HIGHER AMOUNTS ARE QUITE
POSSIBLE GIVEN A PERIOD OF UPSLOPE SUN/SUN NIGHT. COLD AIR WILL
SETTLE OVER THE REGION ON THE BACKSIDE OF THIS SYSTEM WITH BELOW
NORMAL TEMPS FORECAST MON. UPPER LEVEL RIDGING WILL DEVELOP BY
TUE...SUPPORTING WARMING TEMPS THROUGH WED...WITH NORMAL TO ABOVE
NORMAL TEMPS BY THEN...ESP IN AREAS THAN DON/T SEE MUCH SNOW THIS
WEEKEND.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...WFO UNR
LONG TERM...WFO UNR
AVIATION...HELGESON
UPDATE...HELGESON
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
825 AM CST TUE FEB 5 2013
.UPDATE...
GUIDANCE NOW SHOWING CLOUDS LINGERING METROPLEX NORTHEASTWARD
THROUGH THE DAY SO HAVE LOWERED HIGHS IN THOSE AREAS AND ADJUSTED
CLOUD GRIDS. WILL SEND ANOTHER UPDATE WHEN VISIBILITIES IMPROVE.
84
&&
.AVIATION...
LARGE AREA OF IFR/LIFR VISIBILITY AND CEILING RESTRICTIONS
ENCOMPASSES ALL TAF SITES THIS MORNING. EXPECT THESE CONDITIONS TO
PERSIST THROUGH 15Z OR 16Z BEFORE IMPROVING. WENT WITH A FASTER
IMPROVEMENT FOR WACO THAN WHAT MOS IS SHOWING AS WACO CONTINUES TO
BE ON THE WESTERN EDGE OF THE IMPACTS. LOCAL MEDIA REPORTS FROM
WACO INDICATE THAT THE FOG IS SHALLOW WHICH SHOULD BURN OFF QUICKER
THAN WHAT GUIDANCE SHOWS. VFR CONDITIONS ARE EXPECTED THERE THIS
AFTERNOON.
FOR THE METROPLEX...FOG WILL BURN OFF AROUND 16Z AND IFR CIGS
WILL REMAIN...RISING INTO LOW-MVFR CATEGORIES SHORTLY AFTER NOON.
LATEST HIGH-RESOLUTION FORECAST SOUNDINGS INDICATE THAT CIGS WILL
LIKELY REMAIN IN PLACE ALL DAY AND CONTINUE THROUGH TOMORROW
MORNING. WILL SIDE WITH THIS SOLUTION...BUT NOT BE AS PESSIMISTIC
AS THE TTU-WRF WHICH KEEPS IFR IN PLACE. FOG WILL ONCE AGAIN BE
POSSIBLE OVERNIGHT...BUT SOUTHERLY WINDS AT 5 TO 7 KTS SHOULD KEEP
IT UNDER CONTROL.
HAMPSHIRE
&&
.PREV UPDATE...
.UPDATE...
TEMPLE SURFACE OBSERVATION NOW INDICATING WESTERN REACHES OF THE
DENSE FOG ARE REACHING THE I-35 CORRIDOR. WITH HIGHER TERRAIN AND
WEST WINDS 5-10 MPH FURTHER WEST ALONG HWY 190 AROUND KILLEEN...
FORT HOOD...AND COPPERAS COVE...EXPECT THE WORST FOG CONDITIONS
TO BE ALONG AND EAST OF THE I-35 CORRIDOR WITH IMPROVING
CONDITIONS AS YOU HEAD WEST OF THE INTERSTATE.
THE HRRR 2M MOISTURE AND VISIBILITY FORECASTS INDICATES THIS AS
WELL AND HAS BEEN PRETTY ACCURATE WITH THE FOG THIS MORNING. AS A
RESULT...WE HAVE ADDED BELL COUNTY TO THE DENSE FOG ADVISORY THIS
MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 340 AM CST TUE FEB 5 2013/
IMMEDIATE CONCERN IS THE DENSE FOG THAT HAS DEVELOPED ACROSS THE
CENTRAL AND EASTERN PARTS OF NORTH TEXAS EARLY THIS MORNING WHERE
A DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 10 AM CST. THE LINE
IS GENERALLY EAST OF A BOWIE...MINERAL WELLS...MERIDIAN...CAMERON LINE.
THIS INCLUDES THE DFW...WACO...AND SHERMAN AREAS BUT NOT TEMPLE OR
KILLEEN...AS RAP40 DATA KEEPS THE WEAK SURFACE LOW IN THE VICINITY
OF THE STEPHENVILLE/HAMILTON AREA NEARLY STATIONARY...OR ONLY
DRIFTING SOUTH SLIGHTLY THROUGH THIS MORNING. NORTHWEST WINDS
AROUND 10 MPH TO THE WEST OF THIS FEATURE SHOULD KEEP MOST FOG AT
BAY...OR PATCHY AND LIGHT AT BEST. WINDS INCREASING TO NEAR 10 MPH
AND WARMING TEMPERATURES WILL DISSIPATE THE FOG WITH PARTLY SUNNY
CONDITIONS BY AFTERNOON. HIGH PRESSURE TO OUR NORTH WILL SHIFT
EAST TOWARD THE MID-MISSISSIPPI VALLEY LATE TONIGHT WITH PRESSURE
FALLS OFF THE LEE OF THE ROCKIES WHICH WILL INCREASE THE SOUTH
WINDS FOR TUESDAY. BEFORE THAT HAPPENS THOUGH...DEW PTS TONIGHT
WILL REMAIN WELL UP INTO THE 50S WITH SOUTHEAST WINDS GENERALLY
5-10 MPH OR CALM IN PROTECTED AREAS. EXPECT AT LEAST PATCHY FOG
DEVELOPMENT ONCE AGAIN...THOUGH GROUND TEMPS HAVE WARMED RECENTLY.
STILL...SOMETHING THAT BEARS WATCHING.
FOR MID WEEK/WED-THURS...WE CONTINUE TO WATCH A COUPLE OF
DISTURBANCES DROPPING THROUGH THE SUBTROPICAL BRANCH OF THE JET
STREAM ON WATER VAPOR THIS MORNING. ONE OVER THE BAJA PENINSULA OF
NORTHWEST MEXICO WITH ANOTHER LESS DISCERNIBLE SHORTWAVE MOVING
SOUTHEAST ACROSS SOUTHERN CALIFORNIA. BOTH OF THESE DISTURBANCES
WILL TRACK EAST ACROSS SOUTH-CENTRAL TEXAS...WITH MODEST ISENTROPIC
LIFT INTO OUR CENTRAL TEXAS AND EASTERN COUNTIES. THE FIRST
DISTURBANCE WILL BEGIN AFFECTING THESE AREAS LATE WEDNESDAY...WITH
THE OTHER ON ITS HEELS ARRIVING LATER WEDNESDAY NIGHT INTO
THURSDAY. DESPITE CONSIDERABLE CLOUD COVER...ONGOING WAA AND
BREEZY SOUTH WINDS WILL RESULT IN HIGHS MOSTLY IN THE 70S. BEST
RAIN CHANCES WILL BE ACROSS THE SOUTHEAST HALF OF THE CWA WHERE
ACTIVITY SHOULD BE MOSTLY IN THE FORM OF SHOWERS...THOUGH ENOUGH
ELEVATED INSTABILITY WILL BE AVAILABLE FOR ISOLATED THUNDERSTORMS.
ANOTHER COLD FRONT WILL TRACK INTO NORTH TEXAS LATE THURSDAY AND
THURSDAY NIGHT IN WAKE OF THE SECOND DISTURBANCE. THIS SHOULD END
THE SHOWER ACTIVITY...THOUGH SOME MOISTURE POOLING ALONG THE
FRONT MAY LEND TO A FEW SHOWERS ACROSS THE NORTHEAST COUNTIES
THURSDAY NIGHT. COOLER TEMPERATURES ARE EXPECTED MAINLY ACROSS THE
NORTH HALF IN WAKE OF THE WEAK COLD FRONT FRIDAY AS SHORTWAVE
RIDGING SETS UP ALOFT. PRESSURE FALLS IN LEE OF THE ROCKIES FRIDAY
WILL LIFT THIS FRONT BACK NORTH AS A WARM FRONT FRIDAY NIGHT.
BREEZY AND MILD WEATHER RETURNS ONCE AGAIN FOR THE WEEKEND WITH
MOISTURE SLOWLY RETURNING NORTH FROM THE GULF OF MEXICO.
MEANWHILE...A LONGWAVE TROUGH WILL BE DEEPENING OVER THE ROCKIES.
HAVE MADE ONLY MINOR TWEAKS TO EXTENDED FORECAST FOR NEXT WEEKEND
INTO EARLY NEXT WEEK...WITH MEDIUM MODELS DIFFERING ON STRENGTH OF
ENERGY OVER THE GREAT BASIN AND SOUTHWEST STATES WITHIN A BROADER
POSITIVELY TILTED LONGWAVE TROUGH. SATURDAY SHOULD REMAIN
WARM...BREEZY AND WELL CAPPED ALOFT UNDERNEATH STRONG WARM
ADVECTION WITHIN THE FAST SOUTHWEST FLOW ALOFT. DO NOT SEE MUCH
MORE THAN SOME ISOLATED SHOWERS ON SATURDAY. MODELS REALLY DIVERGE
SUNDAY INTO EARLY NEXT WEEK WITH THE ECMWF/CANADIAN MODELS MORE
PROGRESSIVE IN LIFTING OUT LEAD ENERGY AND LESS AMPLIFICATION OF A
LONGWAVE TROUGH OVER THE GULF OF ALASKA. WILL LEAN WITH NCEP WITH
A MORE PROGRESSIVE MOTION. STRONG WAA SHOULD LEAD TO A VIGOROUS
LLJ SATURDAY NIGHT AND HAVE BEST CHANCES ACROSS THE NORTH WHERE
LIFT WILL BE MORE PRONOUNCED AND THE CAPPING INVERSION NOT QUITE
AS STOUT AS IT WILL BE OVER CENTRAL TEXAS. BY SUNDAY...A SURFACE
LOW SHOULD LIFT NORTHEAST ACROSS NORTHERN OK AND KS PULLING A
SURFACE TROUGH THROUGH DURING THE DAY WITH A COLD FRONT ARRIVING
SUNDAY NIGHT AND MONDAY. BEST CHANCE FOR STRONGER STORMS AND ANY
POSSIBLE SEVERE WEATHER SHOULD BE ON SUNDAY AND SUNDAY EVENING
ACROSS THE EAST...BEFORE BRISK AND COOLER CONDITIONS ARRIVE FOR
THE EARLY PART OF NEXT WEEK.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 68 53 72 55 74 / 0 0 10 20 20
WACO, TX 74 52 71 55 77 / 0 10 20 30 10
PARIS, TX 68 49 70 51 67 / 0 5 20 30 40
DENTON, TX 68 50 70 54 70 / 0 0 10 20 20
MCKINNEY, TX 68 48 70 53 70 / 0 5 10 20 30
DALLAS, TX 68 54 72 56 73 / 0 5 10 20 20
TERRELL, TX 69 51 70 54 72 / 0 5 20 30 30
CORSICANA, TX 73 53 72 54 74 / 0 10 30 30 20
TEMPLE, TX 75 52 72 56 77 / 0 10 30 30 10
MINERAL WELLS, TX 70 49 72 52 76 / 0 0 10 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091>095-
102>107-117>123-131>135-144>148-158>162-174-175.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
533 AM CST TUE FEB 5 2013
.AVIATION...
LARGE AREA OF IFR/LIFR VISIBILITY AND CEILING RESTRICTIONS
ENCOMPASSES ALL TAF SITES THIS MORNING. EXPECT THESE CONDITIONS TO
PERSIST THROUGH 15Z OR 16Z BEFORE IMPROVING. WENT WITH A FASTER
IMPROVEMENT FOR WACO THAN WHAT MOS IS SHOWING AS WACO CONTINUES TO
BE ON THE WESTERN EDGE OF THE IMPACTS. LOCAL MEDIA REPORTS FROM
WACO INDICATE THAT THE FOG IS SHALLOW WHICH SHOULD BURN OFF QUICKER
THAN WHAT GUIDANCE SHOWS. VFR CONDITIONS ARE EXPECTED THERE THIS
AFTERNOON.
FOR THE METROPLEX...FOG WILL BURN OFF AROUND 16Z AND IFR CIGS
WILL REMAIN...RISING INTO LOW-MVFR CATEGORIES SHORTLY AFTER NOON.
LATEST HIGH-RESOLUTION FORECAST SOUNDINGS INDICATE THAT CIGS WILL
LIKELY REMAIN IN PLACE ALL DAY AND CONTINUE THROUGH TOMORROW
MORNING. WILL SIDE WITH THIS SOLUTION...BUT NOT BE AS PESSIMISTIC
AS THE TTU-WRF WHICH KEEPS IFR IN PLACE. FOG WILL ONCE AGAIN BE
POSSIBLE OVERNIGHT...BUT SOUTHERLY WINDS AT 5 TO 7 KTS SHOULD KEEP
IT UNDER CONTROL.
HAMPSHIRE
&&
.UPDATE...
TEMPLE SURFACE OBSERVATION NOW INDICATING WESTERN REACHES OF THE
DENSE FOG ARE REACHING THE I-35 CORRIDOR. WITH HIGHER TERRAIN AND
WEST WINDS 5-10 MPH FURTHER WEST ALONG HWY 190 AROUND KILLEEN...
FORT HOOD...AND COPPERAS COVE...EXPECT THE WORST FOG CONDITIONS
TO BE ALONG AND EAST OF THE I-35 CORRIDOR WITH IMPROVING
CONDITIONS AS YOU HEAD WEST OF THE INTERSTATE.
THE HRRR 2M MOISTURE AND VISIBILITY FORECASTS INDICATES THIS AS
WELL AND HAS BEEN PRETTY ACCURATE WITH THE FOG THIS MORNING. AS A
RESULT...WE HAVE ADDED BELL COUNTY TO THE DENSE FOG ADVISORY THIS
MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 340 AM CST TUE FEB 5 2013/
IMMEDIATE CONCERN IS THE DENSE FOG THAT HAS DEVELOPED ACROSS THE
CENTRAL AND EASTERN PARTS OF NORTH TEXAS EARLY THIS MORNING WHERE
A DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 10 AM CST. THE LINE
IS GENERALLY EAST OF A BOWIE...MINERAL WELLS...MERIDIAN...CAMERON LINE.
THIS INCLUDES THE DFW...WACO...AND SHERMAN AREAS BUT NOT TEMPLE OR
KILLEEN...AS RAP40 DATA KEEPS THE WEAK SURFACE LOW IN THE VICINITY
OF THE STEPHENVILLE/HAMILTON AREA NEARLY STATIONARY...OR ONLY
DRIFTING SOUTH SLIGHTLY THROUGH THIS MORNING. NORTHWEST WINDS
AROUND 10 MPH TO THE WEST OF THIS FEATURE SHOULD KEEP MOST FOG AT
BAY...OR PATCHY AND LIGHT AT BEST. WINDS INCREASING TO NEAR 10 MPH
AND WARMING TEMPERATURES WILL DISSIPATE THE FOG WITH PARTLY SUNNY
CONDITIONS BY AFTERNOON. HIGH PRESSURE TO OUR NORTH WILL SHIFT
EAST TOWARD THE MID-MISSISSIPPI VALLEY LATE TONIGHT WITH PRESSURE
FALLS OFF THE LEE OF THE ROCKIES WHICH WILL INCREASE THE SOUTH
WINDS FOR TUESDAY. BEFORE THAT HAPPENS THOUGH...DEW PTS TONIGHT
WILL REMAIN WELL UP INTO THE 50S WITH SOUTHEAST WINDS GENERALLY
5-10 MPH OR CALM IN PROTECTED AREAS. EXPECT AT LEAST PATCHY FOG
DEVELOPMENT ONCE AGAIN...THOUGH GROUND TEMPS HAVE WARMED RECENTLY.
STILL...SOMETHING THAT BEARS WATCHING.
FOR MID WEEK/WED-THURS...WE CONTINUE TO WATCH A COUPLE OF
DISTURBANCES DROPPING THROUGH THE SUBTROPICAL BRANCH OF THE JET
STREAM ON WATER VAPOR THIS MORNING. ONE OVER THE BAJA PENINSULA OF
NORTHWEST MEXICO WITH ANOTHER LESS DISCERNIBLE SHORTWAVE MOVING
SOUTHEAST ACROSS SOUTHERN CALIFORNIA. BOTH OF THESE DISTURBANCES
WILL TRACK EAST ACROSS SOUTH-CENTRAL TEXAS...WITH MODEST ISENTROPIC
LIFT INTO OUR CENTRAL TEXAS AND EASTERN COUNTIES. THE FIRST
DISTURBANCE WILL BEGIN AFFECTING THESE AREAS LATE WEDNESDAY...WITH
THE OTHER ON ITS HEELS ARRIVING LATER WEDNESDAY NIGHT INTO
THURSDAY. DESPITE CONSIDERABLE CLOUD COVER...ONGOING WAA AND
BREEZY SOUTH WINDS WILL RESULT IN HIGHS MOSTLY IN THE 70S. BEST
RAIN CHANCES WILL BE ACROSS THE SOUTHEAST HALF OF THE CWA WHERE
ACTIVITY SHOULD BE MOSTLY IN THE FORM OF SHOWERS...THOUGH ENOUGH
ELEVATED INSTABILITY WILL BE AVAILABLE FOR ISOLATED THUNDERSTORMS.
ANOTHER COLD FRONT WILL TRACK INTO NORTH TEXAS LATE THURSDAY AND
THURSDAY NIGHT IN WAKE OF THE SECOND DISTURBANCE. THIS SHOULD END
THE SHOWER ACTIVITY...THOUGH SOME MOISTURE POOLING ALONG THE
FRONT MAY LEND TO A FEW SHOWERS ACROSS THE NORTHEAST COUNTIES
THURSDAY NIGHT. COOLER TEMPERATURES ARE EXPECTED MAINLY ACROSS THE
NORTH HALF IN WAKE OF THE WEAK COLD FRONT FRIDAY AS SHORTWAVE
RIDGING SETS UP ALOFT. PRESSURE FALLS IN LEE OF THE ROCKIES FRIDAY
WILL LIFT THIS FRONT BACK NORTH AS A WARM FRONT FRIDAY NIGHT.
BREEZY AND MILD WEATHER RETURNS ONCE AGAIN FOR THE WEEKEND WITH
MOISTURE SLOWLY RETURNING NORTH FROM THE GULF OF MEXICO.
MEANWHILE...A LONGWAVE TROUGH WILL BE DEEPENING OVER THE ROCKIES.
HAVE MADE ONLY MINOR TWEAKS TO EXTENDED FORECAST FOR NEXT WEEKEND
INTO EARLY NEXT WEEK...WITH MEDIUM MODELS DIFFERING ON STRENGTH OF
ENERGY OVER THE GREAT BASIN AND SOUTHWEST STATES WITHIN A BROADER
POSITIVELY TILTED LONGWAVE TROUGH. SATURDAY SHOULD REMAIN
WARM...BREEZY AND WELL CAPPED ALOFT UNDERNEATH STRONG WARM
ADVECTION WITHIN THE FAST SOUTHWEST FLOW ALOFT. DO NOT SEE MUCH
MORE THAN SOME ISOLATED SHOWERS ON SATURDAY. MODELS REALLY DIVERGE
SUNDAY INTO EARLY NEXT WEEK WITH THE ECMWF/CANADIAN MODELS MORE
PROGRESSIVE IN LIFTING OUT LEAD ENERGY AND LESS AMPLIFICATION OF A
LONGWAVE TROUGH OVER THE GULF OF ALASKA. WILL LEAN WITH NCEP WITH
A MORE PROGRESSIVE MOTION. STRONG WAA SHOULD LEAD TO A VIGOROUS
LLJ SATURDAY NIGHT AND HAVE BEST CHANCES ACROSS THE NORTH WHERE
LIFT WILL BE MORE PRONOUNCED AND THE CAPPING INVERSION NOT QUITE
AS STOUT AS IT WILL BE OVER CENTRAL TEXAS. BY SUNDAY...A SURFACE
LOW SHOULD LIFT NORTHEAST ACROSS NORTHERN OK AND KS PULLING A
SURFACE TROUGH THROUGH DURING THE DAY WITH A COLD FRONT ARRIVING
SUNDAY NIGHT AND MONDAY. BEST CHANCE FOR STRONGER STORMS AND ANY
POSSIBLE SEVERE WEATHER SHOULD BE ON SUNDAY AND SUNDAY EVENING
ACROSS THE EAST...BEFORE BRISK AND COOLER CONDITIONS ARRIVE FOR
THE EARLY PART OF NEXT WEEK.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 72 53 72 55 74 / 0 0 10 20 20
WACO, TX 74 52 71 55 77 / 0 10 20 30 10
PARIS, TX 67 49 70 51 67 / 0 5 20 30 40
DENTON, TX 70 50 70 54 70 / 0 0 10 20 20
MCKINNEY, TX 68 48 70 53 70 / 0 5 10 20 30
DALLAS, TX 71 54 72 56 73 / 0 5 10 20 20
TERRELL, TX 70 51 70 54 72 / 0 5 20 30 30
CORSICANA, TX 72 53 72 54 74 / 0 10 30 30 20
TEMPLE, TX 75 52 72 56 77 / 0 10 30 30 10
MINERAL WELLS, TX 70 49 72 52 76 / 0 0 10 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091>095-
102>107-117>123-131>135-144>148-158>162-174-175.
&&
$$
85/85
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
459 AM CST TUE FEB 5 2013
.UPDATE...
TEMPLE SURFACE OBSERVATION NOW INDICATING WESTERN REACHES OF THE
DENSE FOG ARE REACHING THE I-35 CORRIDOR. WITH HIGHER TERRAIN AND
WEST WINDS 5-10 MPH FURTHER WEST ALONG HWY 190 AROUND KILLEEN...
FORT HOOD...AND COPPERAS COVE...EXPECT THE WORST FOG CONDITIONS
TO BE ALONG AND EAST OF THE I-35 CORRIDOR WITH IMPROVING
CONDITIONS AS YOU HEAD WEST OF THE INTERSTATE.
THE HRRR 2M MOISTURE AND VISIBILITY FORECASTS INDICATES THIS AS
WELL AND HAS BEEN PRETTY ACCURATE WITH THE FOG THIS MORNING. AS A
RESULT...WE HAVE ADDED BELL COUNTY TO THE DENSE FOG ADVISORY THIS
MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 340 AM CST TUE FEB 5 2013/
IMMEDIATE CONCERN IS THE DENSE FOG THAT HAS DEVELOPED ACROSS THE
CENTRAL AND EASTERN PARTS OF NORTH TEXAS EARLY THIS MORNING WHERE
A DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 10 AM CST. THE LINE
IS GENERALLY EAST OF A BOWIE...MINERAL WELLS...MERIDIAN...CAMERON LINE.
THIS INCLUDES THE DFW...WACO...AND SHERMAN AREAS BUT NOT TEMPLE OR
KILLEEN...AS RAP40 DATA KEEPS THE WEAK SURFACE LOW IN THE VICINITY
OF THE STEPHENVILLE/HAMILTON AREA NEARLY STATIONARY...OR ONLY
DRIFTING SOUTH SLIGHTLY THROUGH THIS MORNING. NORTHWEST WINDS
AROUND 10 MPH TO THE WEST OF THIS FEATURE SHOULD KEEP MOST FOG AT
BAY...OR PATCHY AND LIGHT AT BEST. WINDS INCREASING TO NEAR 10 MPH
AND WARMING TEMPERATURES WILL DISSIPATE THE FOG WITH PARTLY SUNNY
CONDITIONS BY AFTERNOON. HIGH PRESSURE TO OUR NORTH WILL SHIFT
EAST TOWARD THE MID-MISSISSIPPI VALLEY LATE TONIGHT WITH PRESSURE
FALLS OFF THE LEE OF THE ROCKIES WHICH WILL INCREASE THE SOUTH
WINDS FOR TUESDAY. BEFORE THAT HAPPENS THOUGH...DEW PTS TONIGHT
WILL REMAIN WELL UP INTO THE 50S WITH SOUTHEAST WINDS GENERALLY
5-10 MPH OR CALM IN PROTECTED AREAS. EXPECT AT LEAST PATCHY FOG
DEVELOPMENT ONCE AGAIN...THOUGH GROUND TEMPS HAVE WARMED RECENTLY.
STILL...SOMETHING THAT BEARS WATCHING.
FOR MID WEEK/WED-THURS...WE CONTINUE TO WATCH A COUPLE OF
DISTURBANCES DROPPING THROUGH THE SUBTROPICAL BRANCH OF THE JET
STREAM ON WATER VAPOR THIS MORNING. ONE OVER THE BAJA PENINSULA OF
NORTHWEST MEXICO WITH ANOTHER LESS DISCERNIBLE SHORTWAVE MOVING
SOUTHEAST ACROSS SOUTHERN CALIFORNIA. BOTH OF THESE DISTURBANCES
WILL TRACK EAST ACROSS SOUTH-CENTRAL TEXAS...WITH MODEST ISENTROPIC
LIFT INTO OUR CENTRAL TEXAS AND EASTERN COUNTIES. THE FIRST
DISTURBANCE WILL BEGIN AFFECTING THESE AREAS LATE WEDNESDAY...WITH
THE OTHER ON ITS HEELS ARRIVING LATER WEDNESDAY NIGHT INTO
THURSDAY. DESPITE CONSIDERABLE CLOUD COVER...ONGOING WAA AND
BREEZY SOUTH WINDS WILL RESULT IN HIGHS MOSTLY IN THE 70S. BEST
RAIN CHANCES WILL BE ACROSS THE SOUTHEAST HALF OF THE CWA WHERE
ACTIVITY SHOULD BE MOSTLY IN THE FORM OF SHOWERS...THOUGH ENOUGH
ELEVATED INSTABILITY WILL BE AVAILABLE FOR ISOLATED THUNDERSTORMS.
ANOTHER COLD FRONT WILL TRACK INTO NORTH TEXAS LATE THURSDAY AND
THURSDAY NIGHT IN WAKE OF THE SECOND DISTURBANCE. THIS SHOULD END
THE SHOWER ACTIVITY...THOUGH SOME MOISTURE POOLING ALONG THE
FRONT MAY LEND TO A FEW SHOWERS ACROSS THE NORTHEAST COUNTIES
THURSDAY NIGHT. COOLER TEMPERATURES ARE EXPECTED MAINLY ACROSS THE
NORTH HALF IN WAKE OF THE WEAK COLD FRONT FRIDAY AS SHORTWAVE
RIDGING SETS UP ALOFT. PRESSURE FALLS IN LEE OF THE ROCKIES FRIDAY
WILL LIFT THIS FRONT BACK NORTH AS A WARM FRONT FRIDAY NIGHT.
BREEZY AND MILD WEATHER RETURNS ONCE AGAIN FOR THE WEEKEND WITH
MOISTURE SLOWLY RETURNING NORTH FROM THE GULF OF MEXICO.
MEANWHILE...A LONGWAVE TROUGH WILL BE DEEPENING OVER THE ROCKIES.
HAVE MADE ONLY MINOR TWEAKS TO EXTENDED FORECAST FOR NEXT WEEKEND
INTO EARLY NEXT WEEK...WITH MEDIUM MODELS DIFFERING ON STRENGTH OF
ENERGY OVER THE GREAT BASIN AND SOUTHWEST STATES WITHIN A BROADER
POSITIVELY TILTED LONGWAVE TROUGH. SATURDAY SHOULD REMAIN
WARM...BREEZY AND WELL CAPPED ALOFT UNDERNEATH STRONG WARM
ADVECTION WITHIN THE FAST SOUTHWEST FLOW ALOFT. DO NOT SEE MUCH
MORE THAN SOME ISOLATED SHOWERS ON SATURDAY. MODELS REALLY DIVERGE
SUNDAY INTO EARLY NEXT WEEK WITH THE ECMWF/CANADIAN MODELS MORE
PROGRESSIVE IN LIFTING OUT LEAD ENERGY AND LESS AMPLIFICATION OF A
LONGWAVE TROUGH OVER THE GULF OF ALASKA. WILL LEAN WITH NCEP WITH
A MORE PROGRESSIVE MOTION. STRONG WAA SHOULD LEAD TO A VIGOROUS
LLJ SATURDAY NIGHT AND HAVE BEST CHANCES ACROSS THE NORTH WHERE
LIFT WILL BE MORE PRONOUNCED AND THE CAPPING INVERSION NOT QUITE
AS STOUT AS IT WILL BE OVER CENTRAL TEXAS. BY SUNDAY...A SURFACE
LOW SHOULD LIFT NORTHEAST ACROSS NORTHERN OK AND KS PULLING A
SURFACE TROUGH THROUGH DURING THE DAY WITH A COLD FRONT ARRIVING
SUNDAY NIGHT AND MONDAY. BEST CHANCE FOR STRONGER STORMS AND ANY
POSSIBLE SEVERE WEATHER SHOULD BE ON SUNDAY AND SUNDAY EVENING
ACROSS THE EAST...BEFORE BRISK AND COOLER CONDITIONS ARRIVE FOR
THE EARLY PART OF NEXT WEEK.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 72 53 72 55 74 / 0 0 10 20 20
WACO, TX 74 52 71 55 77 / 0 10 20 30 10
PARIS, TX 67 49 70 51 67 / 0 5 20 30 40
DENTON, TX 70 50 70 54 70 / 0 0 10 20 20
MCKINNEY, TX 68 48 70 53 70 / 0 5 10 20 30
DALLAS, TX 71 54 72 56 73 / 0 5 10 20 20
TERRELL, TX 70 51 70 54 72 / 0 5 20 30 30
CORSICANA, TX 72 53 72 54 74 / 0 10 30 30 20
TEMPLE, TX 75 52 72 56 77 / 0 10 30 30 10
MINERAL WELLS, TX 70 49 72 52 76 / 0 0 10 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091>095-
102>107-117>123-131>135-144>148-158>162-174-175.
&&
$$
85/05
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
854 PM CST WED FEB 6 2013
.UPDATE...HAVE ALREADY UPDATED THE GRIDS/ZFP/SPS/WSW/HWO.
MAIN BAND OF SNOW THAT BROUGHT 1-3 INCHES OF SNOW TO THE FORECAST
AREA WAS TAPERING OFF OVER FAR NE WI. SYNOPTIC SCALE FORCING IS
EXPECTED TO WEAKEN OVERNIGHT...AND MID-LEVEL DRY AIR IS FCST TO
MOVE INTO THE RGN. ALTHOUGH SCT/OCNL LIGHT SNOW MAY CONTINUE
OVERNIGHT...ESPECIALLY IN OUR SOUTHERN COUNTIES...THE MAIN PCPN
TYPE IS EXPECTED TO TRANSITION TO FREEZING DRIZZLE. THIS THREAT
WILL JUSTIFY KEEPING THE ADVISORY GOING THROUGH THE NIGHTTIME HOURS.
ON THURSDAY...STRONG UPPER DIVG DUE TO THE RRQ OF AN UPPER JET AND
SHARP UPPER TROF WILL CAUSE SIGNIFICANT SNOW TO REDEVELOP ACROSS
THE SE HALF OF THE FORECAST AREA. ADDITIONAL ACCUMS OF 3 TO 5
INCHES ARE EXPECTED ACROSS THE FOX VALLEY/LKSHR AREAS FROM LATE
THURSDAY MORNING THROUGH THURSDAY EVG...WITH 1 TO 3 INCHES ACROSS
THE NW PORTION OF THE ADVISORY AREA.
HAVE ADJUSTED THE SEGMENTS OF THE WSW TO ACCOUNT FOR THE DIFFERENCES
IN EXPECTED SNOWFALL ACCUMS ON THURSDAY.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 540 PM CST WED FEB 6 2013...
SHORT TERM...TONIGHT AND THURSDAY.
WINTER WEATHER ADVISORY FOR SNOW AND FREEZING DRIZZLE IS THE MAIN
CONCERN DURING THIS PART OF THE FORECAST. MODELS SHOWED
SIGNIFICANT UPPER LEVEL DIVERGENCE ACROSS MUCH OF THE FORECAST
AREA LATE THIS AFTERNOON AND TONIGHT. THIS WAS ASSOCIATED WITH
THE RIGHT ENTRANCE REGION OF A 120+ KNOT 300MB JET MAX. STRONG
UPPER DIVERGENCE ASSOCIATED WITH A WEAKER JET MAX RETURNS TO THE
AREA ON THURSDAY. THE COMBINATION OF LIFT FROM WARM ADVECTION AND
UPPER DIVERGENCE WAS PRODUCING A BAND OF SNOW THAT EXTENDED FROM
THE MINNESOTA ARROWHEAD SOUTHEAST TO SOUTHERN WISCONSIN. SNOWFALL
IN THIS BAND WAS RATHER HEAVY SO IT SHOULD PRODUCE A QUICK
ACCUMULATION OF AN INCH OR TWO AS IT PASSES. RADAR SHOWED A BAND
OF ECHOES ACROSS NORTHERN IOWA BUT SURFACE OBSERVATIONS WERE NOT
INDICATING PRECIPITATION WITH THIS FEATURE. THE 18Z RUC SHOWED QPF
IN THIS AREA SPREADING NORTHEAST INTO CENTRAL AND EASTERN
WISCONSIN OVERNIGHT. MODELS HINTED AT SOME MID LEVEL DRYING
AFTER MIDNIGHT SO HAVE FREEZING DRIZZLE MENTIONED ALONG WITH THE
SNOW.
AN INVERTED SURFACE TROUGH AXIS IS EXPECTED TO PASS THROUGH THE
AREA ON THURSDAY. A 500MB SHORT WAVE APPROACHING THE STATE WILL
COMBINE WITH THE UPPER DIVERGENCE AND SURFACE BOUNDARY TO PRODUCE
MORE SIGNIFICANT SNOWFALL...MAINLY ACROSS EAST CENTRAL WISCONSIN.
TIME/HEIGHT SECTIONS FROM THE 12Z NAM/12Z GFS/09Z SREF DID NOT
INDICATE FREEZING PRECIPITATION FOR ANY OF THE LOCATIONS IN THE
AREA DURING THE SHORT TERM...THOUGH THEY DID IN THE MSN AND MKE
AREAS. HPC WINTER PRECIPITATION GUIDANCE KEPT ANY MEASURABLE
FREEZING PRECIPITATION SOUTH OF THE AREA WITH 24 HOUR TOTALS
THROUGH 00Z FRIDAY OF 6+ INCHES FROM JUST EAST OF GREEN BAY AND
THE FOX CITIES TO LAKE MICHIGAN.
LONG TERM...THU NGT THRU NEXT WED. A NEARLY ZONAL FLOW ACROSS THE
CONUS AT THE ONSET TO TRANSITION TO AN AMPLIFIED FLOW THIS WEEKEND
AS A LARGE UPR RDG BUILDS OFF THE WEST COAST AND A DOWNSTREAM
LONGWAVE TROF SETS UP OVER THE ROCKIES INTO THE CNTRL CONUS. MDLS
CONT TO SHOW A MAJOR SYSTEM WL LIFT NE FROM CO INTO THE GREAT
LAKES SAT NGT INTO MON BRINGING SNOW AND MIXED PCPN TO NE WI. MEAN
FLOW EVENTUALLY BECOMES SPLIT OVER THE ERN PACIFIC WITH THE UPR
TROF SHIFTING EAST. HOWEVER...A SFC HI SHOULD KEEP THE WEATHER
RELATIVELY QUIET WITH TEMPS OVERALL SLIGHTLY ABOVE NORMAL.
LIGHT SNOW TO LINGER INTOI THU EVENING AS THE SHORTWAVE TROF MOVES
THRU WI. CONCERNED ABOUT ERN WI WHERE LIFT IS STRONGER AND WINDS
JUST ABOVE THE SFC ARE FCST TO BE N-NE. MAY NEED TO RAISE POPS A
BIT...ESPECIALLY IN THE EAST WHERE LAKE ENHANCEMENT TO TAKE PLACE
AND THIS COULD ADD UP TO AN INCH OF ADDITIONAL ACCUMULATION. PCPN
WL TAPER OFF FROM WEST TO EAST DURING THE OVRNGT HOURS...ALTHO THE
LAKESHORE MAY NOT SEE THE SNOW COME TO A COMPLETE END TIL CLOSE TO
DAYBREAK. HI PRES BUILDING INTO THE WRN GREAT LAKES LATER THU NGT
COULD BEGIN TO BREAK UP THE CLOUDS ACROSS CNTRL WI AND MAY NEED TO
LWER TEMPS A BIT TO COMPENSATE. THIS AREA OF HI PRES WL BE SITUATED
OVER WI ON FRI PROVIDING FOR PLENTY OF SUNSHINE...LIGHT WINDS AND
TYPICAL TEMPS FOR EARLY FEBRUARY. LOOK FOR READINGS TO GENERALLY
REACH THE 25-30 DEG RANGE OVER ALL OF NE WI.
THE HI PRES BEGINS TO SLIDE TO OUR EAST FRI NGT ALLOWING A RETURN
FLOW TO DEVELOP OVER WI. THE ONSET OF WEAK ISEN LIFT SHOULD BRING
SOME HI CLOUDS INTO THE FCST AREA...HOWEVER STILL EXPECT TEMPS TO
DROP OFF DUE TO FRESH SNOW AND LIGHT WINDS. PREFER THE COLDER SIDE
OF GUIDANCE AND HAVE SIGNIFICANTLY CHOPPED TEMPS INTO THE SINGLE
DIGITS/LOWER TEENS. AS THE LONGWAVE TROF CHUGS ACROSS THE ROCKIES
ON SAT...LEE-SIDE CYCLOGENESIS TO TAKE PLACE OVER SE CO AS A SFC
LOW QUICKLY INTENSIFIES. MEANWHILE...THE SFC HI CONTS TO PULL
FARTHER EAST AND THE SOUTH WINDS STEADILY INCREASE AS THE PRES
GRADIENT TIGHTENS. THESE SOUTH WINDS WL ALSO HELP BRING GULF
MOISTURE NWD...SO WE SHOULD SEE CLOUDS ON THE INCREASE DURING THE
DAY. MAX TEMPS ARE EXPECTED TO REACH NEAR THE 30 DEG MARK DESPITE
THE CLOUDS.
AS A 110+ KT UPR JET ROUNDS THE BASE OF THE UPR TROF...THE SFC LOW
IS FCST TO START MOVING NE INTO THE CNTRL PLAINS SAT NGT AND REACH
THE MIDWEST (VICINITY NW IA) ON SUNDAY. LOW-LEVEL MOISTURE CONTS
TO STREAM INTO WI WITH A WRMFNT LIFTING TO THE WI/IL BORDER BY
SUNDAY AFTERNOON. MID-LEVEL FORCING (BOTH Q-G AND FRONTOGENETICAL)
INCREASE DURING THIS PERIOD OVER THE REGION WITH THE LEFT EXIT
REGION OF THE UPR JET ADDING LIFT. EXPECT TO SEE PCPN GRADUALLY
OVERSPREAD WI ON SUNDAY...BUT WHAT TYPE OF PCPN? WHILE MOST OF THE
MDLS ARE GETTING CLOSER TO A FINAL TRACK SOLUTION (EXCEPT THE GEM
WHICH REMAINS SOUTH)...THE THERMAL FIELDS VARY BETWEEN THE WARMER
GFS AND THE COOLER ECWMF/UKMET. DIFFICULT TO DETERMINE WHAT THE
SFC TEMPS TO BE AT ONCE THE PCPN BEGINS...AS THIS WOULD PLAY A
LARGE ROLE IN DETERMINING RAIN VS. FREEZING RAIN VS. SNOW. IN
ESSENCE...IT IS JUST TOO EARLY TO TRY AND PINPOINT PCPN TYPES AT
THIS TIME...OTHER THAN N-CNTRL WOULD HAVE THE BEST CHC OF SEEING
ALL SNOW AND E-CNTRL WI WOULD HAVE THE BEST CHC OF SEEING MORE
RAIN THAN SNOW WITH A MIX IN BETWEEN.
SNOW/MIXED PCPN WL CONT SUNDAY NGT AS THE SFC LOW TRACKS NE INTO
N-CNTRL WI WITH THE BETTER SNOW ACCUMULATION OCCURRING OVER THE NW
1/4 OF WI. THIS WOULD LIKELY CLIP PARTS OF N-CNTRL WI...BUT FOR
MOST OF THE FCST AREA...TOO MUCH OF A MIX WL LIMIT SNOW AMOUNTS.
AS THE SFC LOW PULLS AWAY ON MON AND COLDER AIR GETS PULLED SWD...
ANY LINGERING MOISTURE WOULD TRANSITION BACK TO ALL SNOW. SINCE
DEEPER MOISTURE TO ALREADY HAVE EXITED...DO NOT EXPECT TO SEE MUCH
ADDITIONAL ACCUMULATION ON MON...ESPECIALLY IF SOME FREEZING
DRIZZLE MIXES IN. OTHER THAN SOME LIGHT LAKE EFFECT SNOW SHWRS
OVER VILAS CNTY MON NGT...THE WEATHER BECOMES FAIRLY TRANQUIL WITH
PERHAPS SOME FLURRIES ON TUE AS THE POSITIVE-TILTED UPR TROF MOVES
THRU THE GREAT LAKES. HI PRES PASSING TO OUR SOUTH ON WED WL BRING
A DRY DAY WITH TEMPS WARMING UP A BIT.
&&
.AVIATION...A BAND OF MODERATE SNOW WILL CONTINUE TO SHIFT EAST
EARLY THIS EVENING...AND SHOULD MOVE OUT OF FAR NE WI BY AROUND
8 PM. THERE SHOULD BE A LULL IN THE SNOW ACCUMULATION LATER THIS
EVENING THROUGH LATE THURSDAY MORNING...ALTHOUGH OCNL LIGHT SNOW
AND FREEZING DRIZZLE (AND IFR CONDITIONS) CAN BE EXPECTED DURING
THIS PERIOD. THE SNOW SHOULD PICK UP AGAIN BEFORE MIDDAY THURS...
AND BE HEAVIEST OVER THE FOX VALLEY/LKSHR AREAS DURING THE
AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ013-
020>022-030-031-035>040-045-048>050-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
553 PM CST WED FEB 6 2013
.SHORT TERM...TONIGHT
553 PM CST WED FEB 6 2013
DRYING AND SUBSIDENCE HAS COME IN BEHIND THE BAND OF SNOW THAT
IMPACTED TAYLOR/CLARK COUNTIES THE PAST FEW HOURS. THIS DRYING AND
SUBSIDENCE HAS EFFECTIVELY ENDED MUCH OF THE PRECIPITATION ACROSS
SOUTHEAST MINNESOTA AND IN REALITY MOST LOCATIONS NORTH OF
INTERSTATE 90. MEANWHILE...AN AREA OF WARM ADVECTION PRECIPITATION
CONTINUES ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
06.12Z HIRES ARW AND 06.20Z RAP/HRRR RUNS HAVE ALL HAD A DECENT
HANDLE ON THE ONGOING PRECIPITATION TRENDS...KEEPING THE BULK OF
THE PRECIPITATION THIS EVENING ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN AND PERHAPS JUNEAU/ADAMS COUNTIES. MUCH OF
SOUTHEAST MINNESOTA INTO BUFFALO...TREMPEALEAU AND LA CROSSE
COUNTIES STAY DRY. AS A RESULT...CONFIDENCE IS JUST NOT HIGH
ENOUGH TO MAINTAIN THE ADVISORY FOR MUCH OF THIS AREA FOR THE
EVENING HOURS. FILLMORE...HOUSTON AND LA CROSSE COUNTIES COULD BE
ON THE VERY EDGE OF HAVING SOME PRECIPITATION DRIFT IN AND
OUT...THOUGH. IN JACKSON/MONROE/JUNEAU/ADAMS/TAYLOR/CLARK...THE
RECENT SNOW HAS HELD TEMPERATURES DOWN...AND WITH HIGHER MOISTURE
APPROACHING FROM THE SOUTH...CONCERNED FREEZING DRIZZLE COULD
DEVELOP AS SUGGESTED BY RAP SOUNDINGS. THUS...HAVE MAINTAINED THE
ADVISORY FOR THIS AREA DURING THE EVENING. AFTER MIDNIGHT AND
EVEN INTO THURSDAY MORNING...CONFIDENCE INCREASES OF BOTH FREEZING
DRIZZLE AND FOG DEVELOPING OVER THE NORTHWEST HALF OF THE FORECAST
AREA...ESPECIALLY TOWARDS LATE IN THE NIGHT...WITH THE POTENTIAL
SUGGESTED OF THE MID CLOUDS CLEARING OUT. WILL REALLY HAVE TO
WATCH VISIBILITIES WITH THE FOG...WHICH IS DISCUSSED MORE IN THE
AVIATION SECTION BELOW.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
223 PM CST WED FEB 6 2013
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SYSTEM THAT MOVES
THROUGH THE REGION SATURDAY NIGHT THROUGH SUNDAY NIGHT. THE 06.12Z
GFS/ECMWF HAVE COME INTO FAIRLY GOOD AGREEMENT WITH A CONTINUED
NORTHWARD SHIFT WITH THE TRACK OF THE LOW. THIS SYSTEM IS CURRENTLY
LOCATED OFF OF THE COAST OF THE PACIFIC NORTHWEST AND WILL STALL OUT
ACROSS THE CENTRAL US ROCKIES EARLY THIS WEEKEND. THE EASTERN
PORTION OF THE TROUGH EJECTS OUT TO THE NORTHEAST INTO THE NORTHERN
PLAINS SATURDAY NIGHT INTO EARLY SUNDAY. THE 06.12Z GFS/ECMWF ARE
AGAIN VERY CONSISTENT WITH THIS RUN FOR TAKING THE CORE OF THE LOW
FROM EASTERN COLORADO SATURDAY NIGHT THROUGH CENTRAL MINNESOTA BY
SUNDAY NIGHT AND THEN INTO THE UPPER GREAT LAKES MONDAY. AT THE
SURFACE...THE LOW IS EXPECTED TO TRACK FROM NORTH CENTRAL IOWA
SUNDAY INTO NORTHERN WISCONSIN BY SUNDAY NIGHT. THIS LEADS TO THE
REGION BEING IN THE WARM SECTOR FOR MOST OF THIS SYSTEM WITH RAIN
BEING THE MAIN PRECIPITATION TYPE. THE BIGGEST CONCERN WILL BE AS
THE PRECIPITATION MOVES IN FROM THE SOUTH SATURDAY NIGHT MIXED
PRECIPITATION TYPES POSSIBLE. DETAILS WILL EMERGE OVER THE NEXT FEW
DAYS...BUT 06.12Z GFS BUFKIT SOUNDINGS SHOW A WARM LAYER OVER A SUB
FREEZING NEAR SURFACE LAYER THAT WOULD LEAD TO A MIX OF SLEET AND
FREEZING RAIN AT THE ONSET. THE LOW LEVEL PROFILE THEN WARMS ENOUGH
THAT MUCH OF SUNDAY SHOULD JUST BE RAIN BEFORE COLDER AIR MOVES IN
ON THE BACK SIDE SUNDAY NIGHT INTO MONDAY.
NOT MUCH IN THE WAY OF COLD AIR ADVECTION ON THE BACK SIDE OF THIS
AMPLIFIED SYSTEM...SO THERE SHOULD NOT BE MUCH OF A COOL DOWN AFTER
THE SYSTEM PASSES. HIGH PRESSURE BUILDS IN AND CONDITIONS SHOULD
REMAIN DRY THROUGH MID WEEK.
&&
.AVIATION...TONIGHT AND THURSDAY
553 PM CST WED FEB 6 2013
COMPLEX AVIATION FORECAST WITH SURFACE LOW CURRENTLY IN CENTRAL
PLAINS EXPECTED TO TRACK SOUTH OF THE AREA OVERNIGHT. A WARM FRONT
DRAPED EAST/WEST NEARBY...WITH A BAND OF LIGHT SNOW AND WINTRY MIX
SOUTH OF TAF SITES. THIS BAND IS EXPECTED TO EXPAND THROUGH THE
NIGHT AS WEAK MOISTURE TRANSPORT POINTS AT THE AREA...BUT THAT THEN
QUICKLY SHIFTS SOUTHEAST. LATEST RADAR SCANS DEPICT SOME
PRECIPITATION MOVING TOWARD KLSE...AND DUAL POL ANALYSIS SUGGESTS A
SNOW/SNOW GRAINS/SLEET MIX...THUS HAVE ADDED A BRIEF TEMPO PERIOD AT
KLSE TO ACCOUNT FOR THIS. FOR KRST...KEPT FORECAST THIS EVENING DRY
AS CURRENT RADAR AND MESO MODELS SUGGEST PRECIPITATION STAYS SOUTH.
MORE CONFIDENT THAT KRST WILL BE DRY THIS EVENING THAN KLSE BEING
SKIRTED BRIEFLY BY SNOW/SLEET...SO WILL MONITOR RADAR AND ADJUST
FORECASTS AS NEEDED.
MOIST AND WARMER AIRMASS IN PLACE SHOULD LEAD TO A GENERAL DECREASE
IN CEILINGS AND VISIBILITIES OVERNIGHT...WITH THE THREAT OF FREEZING
DRIZZLE AFTER MIDNIGHT. KEPT TIMING FROM PREVIOUS FORECAST...BUT
HAVE GONE MORE PESSIMISTIC WITH CONDITIONS. THE HIGHEST
PROBABILITIES FOR 1/4SM OR LESS VISIBILITY LOOK TO BE IN THE 9Z TO
12Z TIME FRAME...AND BOTH AREAS WILL REMAIN IN IFR FOR MUCH OF THE
MORNING HOURS THURSDAY. SOME IMPROVEMENT POSSIBLE IN THE
AFTERNOON...BUT CONFIDENCE IN THIS HAPPENING IS LOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
553 PM CST WED FEB 6 2013
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ017-029-
034-042>044-053>055-061.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
THURSDAY FOR WIZ032-033-041.
MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
THURSDAY FOR MNZ079-086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...ZT
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
540 PM CST WED FEB 6 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY.
WINTER WEATHER ADVISORY FOR SNOW AND FREEZING DRIZZLE IS THE MAIN
CONCERN DURING THIS PART OF THE FORECAST. MODELS SHOWED
SIGNIFICANT UPPER LEVEL DIVERGENCE ACROSS MUCH OF THE FORECAST
AREA LATE THIS AFTERNOON AND TONIGHT. THIS WAS ASSOCIATED WITH
THE RIGHT ENTRANCE REGION OF A 120+ KNOT 300MB JET MAX. STRONG
UPPER DIVERGENCE ASSOCIATED WITH A WEAKER JET MAX RETURNS TO THE
AREA ON THURSDAY. THE COMBINATION OF LIFT FROM WARM ADVECTION AND
UPPER DIVERGENCE WAS PRODUCING A BAND OF SNOW THAT EXTENDED FROM
THE MINNESOTA ARROWHEAD SOUTHEAST TO SOUTHERN WISCONSIN. SNOWFALL
IN THIS BAND WAS RATHER HEAVY SO IT SHOULD PRODUCE A QUICK
ACCUMULATION OF AN INCH OR TWO AS IT PASSES. RADAR SHOWED A BAND
OF ECHOES ACROSS NORTHERN IOWA BUT SURFACE OBSERVATIONS WERE NOT
INDICATING PRECIPITATION WITH THIS FEATURE. THE 18Z RUC SHOWED QPF
IN THIS AREA SPREADING NORTHEAST INTO CENTRAL AND EASTERN
WISCONSIN OVERNIGHT. MODELS HINTED AT SOME MID LEVEL DRYING
AFTER MIDNIGHT SO HAVE FREEZING DRIZZLE MENTIONED ALONG WITH THE
SNOW.
AN INVERTED SURFACE TROUGH AXIS IS EXPECTED TO PASS THROUGH THE
AREA ON THURSDAY. A 500MB SHORT WAVE APPROACHING THE STATE WILL
COMBINE WITH THE UPPER DIVERGENCE AND SURFACE BOUNDARY TO PRODUCE
MORE SIGNIFICANT SNOWFALL...MAINLY ACROSS EAST CENTRAL WISCONSIN.
TIME/HEIGHT SECTIONS FROM THE 12Z NAM/12Z GFS/09Z SREF DID NOT
INDICATE FREEZING PRECIPITATION FOR ANY OF THE LOCATIONS IN THE
AREA DURING THE SHORT TERM...THOUGH THEY DID IN THE MSN AND MKE
AREAS. HPC WINTER PRECIPITATION GUIDANCE KEPT ANY MEASURABLE
FREEZING PRECIPITATION SOUTH OF THE AREA WITH 24 HOUR TOTALS
THROUGH 00Z FRIDAY OF 6+ INCHES FROM JUST EAST OF GREEN BAY AND
THE FOX CITIES TO LAKE MICHIGAN.
.LONG TERM...THU NGT THRU NEXT WED. A NEARLY ZONAL FLOW ACROSS THE
CONUS AT THE ONSET TO TRANSITION TO AN AMPLIFIED FLOW THIS WEEKEND
AS A LARGE UPR RDG BUILDS OFF THE WEST COAST AND A DOWNSTREAM
LONGWAVE TROF SETS UP OVER THE ROCKIES INTO THE CNTRL CONUS. MDLS
CONT TO SHOW A MAJOR SYSTEM WL LIFT NE FROM CO INTO THE GREAT
LAKES SAT NGT INTO MON BRINGING SNOW AND MIXED PCPN TO NE WI. MEAN
FLOW EVENTUALLY BECOMES SPLIT OVER THE ERN PACIFIC WITH THE UPR
TROF SHIFTING EAST. HOWEVER...A SFC HI SHOULD KEEP THE WEATHER
RELATIVELY QUIET WITH TEMPS OVERALL SLIGHTLY ABOVE NORMAL.
LIGHT SNOW TO LINGER INTOI THU EVENING AS THE SHORTWAVE TROF MOVES
THRU WI. CONCERNED ABOUT ERN WI WHERE LIFT IS STRONGER AND WINDS
JUST ABOVE THE SFC ARE FCST TO BE N-NE. MAY NEED TO RAISE POPS A
BIT...ESPECIALLY IN THE EAST WHERE LAKE ENHANCEMENT TO TAKE PLACE
AND THIS COULD ADD UP TO AN INCH OF ADDITIONAL ACCUMULATION. PCPN
WL TAPER OFF FROM WEST TO EAST DURING THE OVRNGT HOURS...ALTHO THE
LAKESHORE MAY NOT SEE THE SNOW COME TO A COMPLETE END TIL CLOSE TO
DAYBREAK. HI PRES BUILDING INTO THE WRN GREAT LAKES LATER THU NGT
COULD BEGIN TO BREAK UP THE CLOUDS ACROSS CNTRL WI AND MAY NEED TO
LWER TEMPS A BIT TO COMPENSATE. THIS AREA OF HI PRES WL BE SITUATED
OVER WI ON FRI PROVIDING FOR PLENTY OF SUNSHINE...LIGHT WINDS AND
TYPICAL TEMPS FOR EARLY FEBRUARY. LOOK FOR READINGS TO GENERALLY
REACH THE 25-30 DEG RANGE OVER ALL OF NE WI.
THE HI PRES BEGINS TO SLIDE TO OUR EAST FRI NGT ALLOWING A RETURN
FLOW TO DEVELOP OVER WI. THE ONSET OF WEAK ISEN LIFT SHOULD BRING
SOME HI CLOUDS INTO THE FCST AREA...HOWEVER STILL EXPECT TEMPS TO
DROP OFF DUE TO FRESH SNOW AND LIGHT WINDS. PREFER THE COLDER SIDE
OF GUIDANCE AND HAVE SIGNIFICANTLY CHOPPED TEMPS INTO THE SINGLE
DIGITS/LOWER TEENS. AS THE LONGWAVE TROF CHUGS ACROSS THE ROCKIES
ON SAT...LEE-SIDE CYCLOGENESIS TO TAKE PLACE OVER SE CO AS A SFC
LOW QUICKLY INTENSIFIES. MEANWHILE...THE SFC HI CONTS TO PULL
FARTHER EAST AND THE SOUTH WINDS STEADILY INCREASE AS THE PRES
GRADIENT TIGHTENS. THESE SOUTH WINDS WL ALSO HELP BRING GULF
MOISTURE NWD...SO WE SHOULD SEE CLOUDS ON THE INCREASE DURING THE
DAY. MAX TEMPS ARE EXPECTED TO REACH NEAR THE 30 DEG MARK DESPITE
THE CLOUDS.
AS A 110+ KT UPR JET ROUNDS THE BASE OF THE UPR TROF...THE SFC LOW
IS FCST TO START MOVING NE INTO THE CNTRL PLAINS SAT NGT AND REACH
THE MIDWEST (VICINITY NW IA) ON SUNDAY. LOW-LEVEL MOISTURE CONTS
TO STREAM INTO WI WITH A WRMFNT LIFTING TO THE WI/IL BORDER BY
SUNDAY AFTERNOON. MID-LEVEL FORCING (BOTH Q-G AND FRONTOGENETICAL)
INCREASE DURING THIS PERIOD OVER THE REGION WITH THE LEFT EXIT
REGION OF THE UPR JET ADDING LIFT. EXPECT TO SEE PCPN GRADUALLY
OVERSPREAD WI ON SUNDAY...BUT WHAT TYPE OF PCPN? WHILE MOST OF THE
MDLS ARE GETTING CLOSER TO A FINAL TRACK SOLUTION (EXCEPT THE GEM
WHICH REMAINS SOUTH)...THE THERMAL FIELDS VARY BETWEEN THE WARMER
GFS AND THE COOLER ECWMF/UKMET. DIFFICULT TO DETERMINE WHAT THE
SFC TEMPS TO BE AT ONCE THE PCPN BEGINS...AS THIS WOULD PLAY A
LARGE ROLE IN DETERMINING RAIN VS. FREEZING RAIN VS. SNOW. IN
ESSENCE...IT IS JUST TOO EARLY TO TRY AND PINPOINT PCPN TYPES AT
THIS TIME...OTHER THAN N-CNTRL WOULD HAVE THE BEST CHC OF SEEING
ALL SNOW AND E-CNTRL WI WOULD HAVE THE BEST CHC OF SEEING MORE
RAIN THAN SNOW WITH A MIX IN BETWEEN.
SNOW/MIXED PCPN WL CONT SUNDAY NGT AS THE SFC LOW TRACKS NE INTO
N-CNTRL WI WITH THE BETTER SNOW ACCUMULATION OCCURRING OVER THE NW
1/4 OF WI. THIS WOULD LIKELY CLIP PARTS OF N-CNTRL WI...BUT FOR
MOST OF THE FCST AREA...TOO MUCH OF A MIX WL LIMIT SNOW AMOUNTS.
AS THE SFC LOW PULLS AWAY ON MON AND COLDER AIR GETS PULLED SWD...
ANY LINGERING MOISTURE WOULD TRANSITION BACK TO ALL SNOW. SINCE
DEEPER MOISTURE TO ALREADY HAVE EXITED...DO NOT EXPECT TO SEE MUCH
ADDITIONAL ACCUMULATION ON MON...ESPECIALLY IF SOME FREEZING
DRIZZLE MIXES IN. OTHER THAN SOME LIGHT LAKE EFFECT SNOW SHWRS
OVER VILAS CNTY MON NGT...THE WEATHER BECOMES FAIRLY TRANQUIL WITH
PERHAPS SOME FLURRIES ON TUE AS THE POSITIVE-TILTED UPR TROF MOVES
THRU THE GREAT LAKES. HI PRES PASSING TO OUR SOUTH ON WED WL BRING
A DRY DAY WITH TEMPS WARMING UP A BIT.
&&
.AVIATION...A BAND OF MODERATE SNOW WILL CONTINUE TO SHIFT EAST
EARLY THIS EVENING...AND SHOULD MOVE OUT OF FAR NE WI BY AROUND
8 PM. THERE SHOULD BE A LULL IN THE SNOW ACCUMULATION LATER THIS
EVENING THROUGH LATE THURSDAY MORNING...ALTHOUGH OCNL LIGHT SNOW
AND FREEZING DRIZZLE (AND IFR CONDITIONS) CAN BE EXPECTED DURING
THIS PERIOD. THE SNOW SHOULD PICK UP AGAIN BEFORE MIDDAY THURS...
AND BE HEAVIEST OVER THE FOX VALLEY/LKSHR AREAS DURING THE
AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ013-
020>022-030-031-035>040-045-048>050-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
323 AM CST THU FEB 7 2013
.DISCUSSION...
MAIN AREA OF PRECIPITATION SO FAR HAS BEEN JUST UPSTREAM OF BEST
LOW-MID LEVEL MOISTURE CONVERGENCE WHERE STRONGER LOW LEVEL JET IS
BEING MAINTAINED EAST OF 850MB LOW. UPPER WAVE CONTINUES ITS
EASTWARD PROGRESS BUT HAS STILL JUST ENTERED THE PLAINS AT 08Z.
LATEST RAP AND 06Z NAM TAKE THIS AREA OF CONVERGENCE EAST THROUGH
THE POST-SUNRISE HOURS WHILE THE UPPER WAVE...CONTINUING TO SLOW
ITS PACE...HELPS SPREAD PRECIP NORTHEAST. THIS WILL KEEP PRECIP IN
PLACE SLIGHTLY LONGER...BUT A QUICK CLEARING IS ON TRACK FOR THE
AFTERNOON AS THE UPPER TROF CLEARS KANSAS. WEAKENING LAPSE RATES
AND LESS-FOCUSED LIFT SHOULD KEEP THUNDERSTORMS IN A ISOLATED
NATURE. MODEST COLD AIR ADVECTION AND GOOD MIXING SHOULD STILL
PUSH HIGHS INTO THE UPPER 40S TO LOWER 50S.
DEEP RIDING TO BE THE RULE INTO FRIDAY. HIGHS FRIDAY STILL SOMEWHAT
IN QUESTION WITH EASTERLY WINDS AND INCREASING HIGH CLOUDS BUT KEPT
TEMPS JUST ABOVE MOS VALUES GIVEN THEIR COOL BIAS THIS SEASON.
PRECIP CHANCES RAMP UP AGAIN SATURDAY INTO SATURDAY NIGHT AS THE
NEXT SYSTEM...ENTERING THE PACIFIC NORTHWEST IN RECENT
HOURS...EMERGES FROM THE ROCKIES. INCREASING SOUTH WINDS AND LARGE
SCALE FORCING BRINGS SOME CHANCE FOR SHOWERS BY SATURDAY
AFTERNOON...WITH THE WETTEST PERIOD EXPECTED SATURDAY NIGHT AS THE
LOW SURGES NORTHEAST INTO THE PLAINS. INSTABILITY DOES NOT LOOK
IMPRESSIVE...BUT ENOUGH FORCING MECHANISMS COME TOGETHER FOR SOME
THUNDER POTENTIAL AGAIN. TEMPS STAY WARM ENOUGH FOR AN ALL LIQUID
EVENT UNTIL PERHAPS SUNDAY AFTERNOON AS COLD AIR COMES IN BEHIND THE
LOW...BUT MEASURABLE AMOUNTS SEEM UNLIKELY AT BEST. SECONDARY SYSTEM
WORKING IN BEHIND WILL NEED TO BE WATCHED...BUT THE BULK OF IT
SHOULD REMAIN SOUTH. WILL INCLUDE SMALL OPPORTUNITIES FOR PRECIP
TUESDAY NIGHT IN FAR SOUTHERN AREAS.
65
&&
.AVIATION...
05Z SFC OBS SHOWS THE FRONT STILL BACK ACROSS NORTHWEST KS. MODELS
SHOW THE BEST PRECIP CHANCES JUST AHEAD OF THE FRONT WITH THE LOW
LEVEL LIFT. SO THERE IS NOT MUCH CHANGE TO THE FORECAST EXCEPT TO
FOLLOW THE TREND OF THE 00Z MODELS TO BE AN HOUR OR TWO SLOWER WITH
THE CIGS/PRECIP/FROPA. CONTINUE TO THINK THERE WILL BE SOME IFR CIGS
AND POTENTIALLY VSBY IF SHOWERS ARE INTENSE ENOUGH. CONFIDENCE IS
ABOUT AVERAGE.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1141 PM CST WED FEB 6 2013
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SCATTERED TO NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS ARE
EXPECTED FOR THE REST OF THE NIGHT...TRANSITIONING FROM PARTS OF
CENTRAL AND SOUTH CENTRAL KANSAS INTO SOUTHEAST KANSAS DURING
THURSDAY MORNING. IFR/LIFR CONDITIONS WILL CONTINUE ALONG AND
JUST AHEAD OF THE APPROACHING COLD FRONT...WITH CONDITIONS
IMPROVING ACROSS CENTRAL KANSAS BY BEFORE DAWN. SHOWERS WITH
PREVAILING MVFR CONDITIONS AND AREAS OF IFR WILL PERSIST THRU
MID-MORNING ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS BEFORE
GUSTY NORTH WINDS AND DRIER AIR BEHIND THE COLD FRONT RESULT IN
VFR CONDITIONS ALL AREAS FOR THE LATTER HALF OF THE FORECAST
VALID PERIOD.
KED
&&
.PREV DISCUSSION... /ISSUED 923 PM CST WED FEB 6 2013/
UPDATE...
CONVECTION HAS DEVELOPED ACROSS NORTHEAST KANSAS AT MID-EVENING
WITH THE LATEST NAM AND RUC DEVELOPING IT SOUTHWEST ACROSS CENTRAL
KANSAS TOWARD MIDNIGHT. THIS IS HANDLED FAIRLY WELL IN CURRENT
FORECAST WITH ONLY SLIGHT TWEAKS INTO THE OVERNIGHT HOURS. PATCHY
FOG AND DRIZZLE WILL CONTINUE AHEAD OF THE FRONT AS A PRECURSOR
TO THE CONVECTION...THOUGH DO NOT EXPECT THE RESTRICTIONS TO BE
LOW ENOUGH AND WIDESPREAD FOR A DENSE FOG HEADLINE AT THE MOMENT.
ELEVATED CAPE VALUES AROUND 500 J/KG AND MODEST SHEAR VALUES MAY
SUPPORT A FEW STRONG STORMS WITH SMALL HAIL AND HAVE MADE A SLIGHT
ADJUSTMENT TO THE RISK AREA OVERNIGHT.
KED
PREV DISCUSSION... /ISSUED 545 PM CST WED FEB 6 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR/IFR CIGS AND VSBYS ARE EXPECTED TO EXPAND ACROSS MUCH OF THE
AREA TONIGHT AS A COLD FRONT SLIDES EAST ACROSS CENTRAL KANSAS.
FOG AND PATCHY DRIZZLE THIS EVENING WILL BE REPLACED BY SCATTERED
TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS LATE IN THE NIGHT.
THIS ACTIVITY IS EXPECTED TO TRANSITION EAST WITH THE COLD FRONT
ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS EARLY THURSDAY MORNING.
GUSTY NORTH WINDS WILL BRING IN DRIER AIR DURING THE DAYLIGHT
HOURS ON THURSDAY WITH CONDITIONS IMPROVING FOR THE LATTER PORTION
OF THE FORECAST VALID PERIOD.
KED
PREV DISCUSSION... /ISSUED 338 PM CST WED FEB 6 2013/
DISCUSSION...
TONIGHT-THU:
MOISTURE WILL CONTINUE TO INCREASE AHEAD OF FRONT. GOOD CHANCE OF
PATCHY TO AREAS OF DRIZZLE/LIGHT SHOWERS AND FOG ACROSS SOUTH
CENTRAL/SOUTHEAST KS AS LOW LEVEL MOISTURE INCREASES AHEAD OF
FRONT. PRECIPITATION SHOULD BREAK OUT IN CENTRAL KS AHEAD OF FRONT
THIS EVENING...WITH CHANCES INCREASE TOWARDS MIDNIGHT. TOUGH CALL
ON BACK EDGE OF PRECIPITATION AT 1200 UTC...BUT LIKELY IN THE
VICINITY OF KHUT/KICT. PRECIPITATION WILL LINGER EAST OF TURNPIKE
THROUGH NOON AND EXTREME SOUTHEAST KS PAST 1800 UTC. TEMPERATURES
WILL BE HELD UP OVERNIGHT AT MOST LOCATIONS WITH SURFACE DEWPOINTS
CLIMBING INTO THE 50S. GUSTY NORTHWEST WINDS ANTICIPATED ON THU IN
WAKE OF FRONT WITH MOSTLY CLEAR SKIES AND GOOD MIXING.
FRI-SUN:
QUIET WEATHER ANTICIPATED ON FRI. TEMPERATURES STILL A BIT TRICKY
AND DEPENDENT ON MIXING HEIGHT WITH FAIRLY WARM AIR ALOFT AND AT
LEAST SOME COLDER AIR NEAR SURFACE. BASED ON RECENT VERIFICATION...
HAVE LEANED A BIT WARMER. BY FRIDAY NIGHT RETURN FLOW WILL BE
UNDERWAY WITH LOW LEVEL MOISTURE ON THE INCREASE. SOME WARM AIR
ADVECTION PRECIPITATION IS EXPECTED TO BREAK OUT SAT MORNING...
WITH CHANCES INCREASE SAT NIGHT/SUN AS SURFACE FRONT APPROACHES.
GFS HAS BEEN UNDERESTIMATING INSTABILITY AND GIVEN SYNOPTIC SET UP
WITH DIFFLUENT SOUTHWEST FLOW ALOFT AND NICE DRYLINE...BELIEVE
THERE IS A DECENT CHANCE OF STORMS DURING THE NIGHT. EVEN WITH
LESS THAN OPTIMAL TIMING OF THE DRYLINE...THE VERY STRONG DEEP
LAYER SHEAR MAY ALLOW SOME STORMS TO GET A BIT FRISKY.
PRECIPITATION CHANCES WILL END ABRUPTLY AS DRY SLOT WORKS ACROSS
THE AREA EARLY ON SUN. TRACK OF SURFACE LOW SHOULD KEEP WRAP
AROUND PRECIPITATION JUST NORTH OF FORECAST AREA.
MON-WED:
RELATIVELY QUIET AND SEASONAL WEATHER ANTICIPATED MON...BUT
DIFFERENCES IN ECMWF ARE EVIDENT ON TUE-WED. WHILE BOTH MORE OR
LESS SHOW SHORTWAVE ENERGY INDUCING SURFACE WAVE ON FRONT TO THE
SOUTH...GFS HAS SLOPPED PRECIPITATION A LOT FURTHER NORTH/NORTHWEST
THAN THE ECMWF. INITIALIZATION GRIDS REFLECTED THIS WITH LOW POPS
ACR SOUTHERN/SOUTHEAST KS. AT THIS TIME...BELIEVE CHANCES ARE SLIM
AND HAVE NIXED ACROSS SOUTH CENTRAL KS..BUT KEPT IN FAR SOUTHEAST
FOR CONSISTENCY. -HOWERTON
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN AVIATION FORECAST CONCERN IS THE IFR/MVFR CONDITIONS
TODAY/TONIGHT AND THUNDERSTORMS POSSIBLE TONIGHT.
LOW STRATUS HAS DEVELOPED ACROSS SOUTH CENTRAL AND NORTH TO
CENTRAL KANSAS AS THE WARM FRONT HAS STREAMED NORTHWARD AND HIGHER
DEWPOINTS ARE INTERACTING WITH THE COOLER TEMPERATURES. EXPECT
MVFR TO HIGH IFR STRATUS TO CONTINUE THROUGH THE NEXT 12-18 HOURS
AT MANY SITES. THE FRONT WILL MOVE THROUGH AND THE UPPER PATTERN
WILL HELP TO FIRE OFF THUNDERSTORMS BEGINNING OVERNIGHT. THINK THE
SITES WITH THE BEST CHANCE FOR THUNDERSTORMS WILL BE
KSLN/KHUT/KICT AND KCNU. THE RAIN WILL MOVE OUT AS THE UPPER WAVE
ROTATES EASTWARD...ENDING THINGS FROM WEST TO EAST THURSDAY
MORNING.
WINDS WILL BECOME NORTHERLY BEHIND THE FRONT AND BE BREEZY...BUT
CEILINGS WILL LIFT AS DRIER AIR MOVES IN.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 51 54 30 57 / 80 60 0 0
HUTCHINSON 47 54 29 55 / 80 30 0 0
NEWTON 49 53 29 56 / 80 50 0 0
ELDORADO 50 53 28 56 / 80 80 0 0
WINFIELD-KWLD 51 55 29 57 / 30 80 0 0
RUSSELL 41 53 27 55 / 40 10 0 0
GREAT BEND 42 53 27 55 / 80 10 0 0
SALINA 44 54 27 57 / 80 10 0 0
MCPHERSON 46 53 28 56 / 80 20 0 0
COFFEYVILLE 48 56 30 58 / 10 80 0 0
CHANUTE 47 53 28 55 / 20 80 0 0
IOLA 47 52 28 54 / 30 80 0 0
PARSONS-KPPF 47 55 29 57 / 20 80 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
1107 PM CST WED FEB 6 2013
...UPDATED SYNOPSIS SECTION...
.SYNOPSIS...
ISSUED AT 1100 PM CST WED FEB 6 2013
THE 00Z UPPER AIR ANALYSIS PORTRAYS A MID TO UPPER LEVEL TROUGH
EXTENDING DOWN THROUGH THE NORTHERN AND CENTRAL ROCKIES WITH A
WEAK RIDGE OF HIGH PRESSURE POSITIONED ACROSS THE PACIFIC
NORTHWEST. A MID TO UPPER LEVEL LOW IS LOCATED FARTHER NORTHWEST
ACROSS THE EASTERN PACIFIC OCEAN. AN AREA OF LOW PRESSURE BECOMES
PRESENT CLOSER TO THE SURFACE WITH A COLD FRONT EXTENDING FROM
IOWA THROUGH NORTHWEST KANSAS AND INTO SOUTHERN COLORADO. WINDS
ARE GENERALLY LIGHT AND VARIABLE AND ALLOWING LOW LEVEL MOISTURE TO
POOL UP AGAINST THIS FRONT. THIS IS ALLOWING LOW CLOUDS AND FOG
TO DEVELOP ACROSS PARTS OF WESTERN KANSAS. TEMPERATURES ACROSS
SOUTHWEST KANSAS CURRENTLY RANGE FROM THE LOWER 40S ACROSS WEST
CENTRAL KANSAS WITH UPPER 40S AND LOWER 50S ELSEWHERE.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 236 PM CST WED FEB 6 2013
TONIGHT:
SEVERAL SENSIBLE WEATHER IMPACTS EXPECTED TONIGHT INTO TOMORROW MORNING.
FIRST IS FOG. HRRR IS VERY AGGRESSIVE IN DEVELOPING LOW VISIBILITIES
AFTER 00Z TONIGHT. THE NAM AND ARW-WRF IS NOT AS AGGRESSIVE WITH FOG.
DUE TO THE WARM AIR ADVECTION PATTERN THAT IS CURRENTLY TAKING PLACE
AND THE HIGHER DEWPOINTS ADVECTING IN ACROSS THE REGION...WILL GO WITH
PATCHY FOG TONIGHT ALONG AND EAST OF HIGHWAY 283 WITH AREAS OF FOG
ALONG SOUTH CENTRAL KANSAS WHERE DEWPOINTS ARE HIGHER. THE NEXT CONCERN
IS CONVECTION. THE BEST CHANCE FOR OVERNIGHT THUNDERSTORMS IS GENERALLY
ALONG AND EAST OF HIGHWAY 183. HERE WARM AIR ADVECTION...ISENTROPIC
LIFT ALONG THE 295 KELVIN THETA SURFACE... AND INCREASING 850-650 HPA
FRONTOGENESIS SHOULD INITIATE CONVECTIVE ACTIVITY AFTER 03Z TONIGHT.
ALL THE MESOSCALE MODELS SUGGESTS THIS AS WELL AS THE GFS AND ECMWF.
SEVERE THUNDERSTORMS ARE NOT EXPECTED DUE TO WEAK THERMODYNAMICS AND
WEAK KINEMATICS. CONVECTION SHOULD BE CLEAR OF THE REGION BY DAWN.
A DENSE FOG ADVISORY COULD BE NEEDED FOR TOMORROW MORNING, BUT DO NOT
HAVE ENOUGH CONFIDENCE TO ISSUE ONE THIS EARLY.
TOMORROW:
TOMORROW MORNING WILL BE BREEZY AS THERE WILL BE A TIGHT PRESSURE GRADIENT
ACROSS THE REGION ALONG WITH 45 KT 850 HPA WINDS PARTIALLY MIXING DOWN.
NOT EXPECTING WIND ADVISORY LEVELS AT THIS TIME. OTHER THAN SOME POSSIBLE
LINGERING FOG, TOMORROW WILL BE FAIRLY QUIET WITH CLEARING SKIES. HIGHS
SHOULD BE IN THE 50S DEG F. WINDS SHOULD ABATE AS THE DAY WEARS ON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 PM CST WED FEB 6 2013
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
MOVING EASTWARD ACROSS THE CENTRAL PLAINS FRIDAY RESULTING IN DRY
CONDITIONS ACROSS WESTERN KANSAS THROUGH FRIDAY NIGHT. MEANWHILE,
A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE IS EXPECTED TO DIG
SOUTHEAST INTO THE GREAT BASIN REGION FRIDAY, THEN TURN EASTWARD
MOVING INTO THE CENTRAL AND SOUTHERN ROCKIES SATURDAY BRINGING THE
POSSIBILITY FOR SHOWERS AND THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS AS EARLY AS SATURDAY AFTERNOON. A RETURN FLOW WILL SET UP
EARLY FRIDAY DRAWING GULF MOISTURE NORTHWARD INTO MUCH OF KANSAS
WITH H85 DEWPOINTS CLIMBING JUST ABOVE 0C. ADDITIONALLY, SURFACE
LOW PRESSURE IN EASTERN COLORADO WILL STRENGTHEN THROUGHOUT THE
DAY WITH A SHARPENING DRYLINE EXTENDING SOUTHWARD GENERALLY INTO
THE TEXAS PANHANDLE. DYNAMIC SUPPORT ALOFT WILL BECOME MORE
FAVORABLE AS WELL WITH THE GFS AND ECMWF SHOWING A STRONG H5 VORT
MAX LIFTING NORTHEAST OUT OF THE TROUGH AXIS AND ACROSS THE
WESTERN HIGH PLAINS SATURDAY NIGHT. A +100KT UPPER LEVEL JET WILL
ALSO BE STREAMING EAST-NORTHEAST ACROSS WEST TEXAS AND THE TEXAS
PANHANDLE INTO THE PLAINS OF WESTERN OKLAHOMA AND SOUTHERN KANSAS
LATE SATURDAY. AS A RESULT, SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP ACROSS THE SOUTH PLAINS SATURDAY AFTERNOON AND EVENING,
LIFTING NORTHEASTWARD INTO CENTRAL KANSAS WITH CHANCES FOR THE
PRECIP DWINDLING TOWARD THE WEST. GFS AND ECMWF MODEL SOUNDINGS
INDICATE A REAL LACK OF INSTABILITY LIMITING SEVERE POTENTIAL.
ANY PRECIP WILL LIKELY COME TO AN END BY MID DAY SUNDAY AS THE
UPPER LEVEL TROUGH BEGINS TO LIFT NORTHEAST INTO THE UPPER
MIDWEST.
TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL FRIDAY EVEN AS SURFACE
HIGH PRESSURE MOVES FROM THE NORTHERN PLAINS SOUTHEAST INTO THE
UPPER MIDWEST. THIS WILL TURN WINDS SOUTH TO SOUTHEASTERLY ACROSS
WESTERN KANSAS THROUGHOUT MUCH OF THE DAY. HOWEVER, THIS WILL DO
LITTLE TO ERODE THE COOLER AIR MASS THAT IS PROJECTED TO SINK
SOUTH INTO WESTERN KANSAS BEHIND A PASSING COLD FRONT THURSDAY.
THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING FROM JUST
ABOVE 0C ACROSS CENTRAL KANSAS TO JUST ABOVE 5C ALONG THE COLORADO
BORDER. LOOK FOR HIGHS WELL UP INTO THE 50S(F) FRIDAY AFTERNOON.
SIMILAR HIGHS ARE LIKELY SATURDAY AS SURFACE LOW PRESSURE
STRENGTHENS ACROSS EASTERN COLORADO KEEPING SOUTHERLY WINDS IN
PLACE ACROSS WESTERN KANSAS. A COLD FRONT PUSHING THROUGH WESTERN
KANSAS SUNDAY WILL ALLOW COLDER AIR TO SURGE SOUTHWARD INTO
WESTERN KANSAS RESULTING IN LOWER HIGH TEMPERATURES. OVERALL,
TEMPERATURES ARE LIKELY TO REMAIN BELOW NORMAL THROUGH MID WEEK AS
A SECONDARY UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTERMOUNTAIN
WEST AND MOVES INTO THE WESTERN HIGH PLAINS DRAWING MORE COLDER
DOWN INTO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 531 PM CST WED FEB 6 2013
THE MAJOR IMPACT TO AVIATION WILL BE DENSE FOG DEVELOPMENT LATE
THIS EVENING AND LASTING THROUGH THE OVERNIGHT. INCREASING LOW
LEVEL MOISTURE AHEAD OF A SURFACE COLD FRONT WILL PROVIDE THE
CONDITIONS FOR ADVECTION FOG ACROSS MUCH OF CENTRAL ANS SOUTHWEST
KANSAS BEGINNING AS EARLY AS 03 UTC. THE LATEST MESOSCALE MODELS
INCLUDING THE VARIOUS NAM ARW CORES AND THE RAPID REFRESH ARE ALL
STRONGLY SUGGESTING DENSE FOG DEVELOPMENT. IT IS BELIEVED THE LOCAL
GFS MOS (LAMP) IS TOO FOCUSED ON NORMAL DIURNAL TRENDS AND LIKELY
INCORRECT. A 700 MB WAVE WILL HELP SET OFF SHOWERS AND ISOLATED
THUNDERSTORM ACROSS CENTRAL KANSAS AS WELL, PROBABLY JUST EAST OF
HAYS AND DODGE CITY BETWEEN MID NIGHT AND 10Z. AT THIS TIME, TEMPO
1/4SM CONDITIONS WILL BE CARRIE UNTIL SUCH CONFIDENCE THAT
PREVAILING CONDITIONS CAN BE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 54 27 56 / 10 0 0 0
GCK 36 53 27 56 / 0 0 0 0
EHA 34 51 27 57 / 0 0 0 0
LBL 37 53 27 57 / 0 0 0 0
HYS 39 53 25 55 / 40 0 0 0
P28 48 55 30 56 / 80 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST THURSDAY FOR KSZ030-031-
043>046-063>066-076>081-086>090.
&&
$$
SYNOPSIS...HOVORKA_42
SHORT TERM...SUGDEN
LONG TERM...JJOHNSON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1102 PM CST WED FEB 6 2013
...UPDATED SYNOPSIS SECTION...
.SYNOPSIS...
ISSUED AT 1100 PM CST WED FEB 6 2013
THE 00Z UPPER AIR ANALYSIS PORTRAYS A MID TO UPPER LEVEL TROUGH
EXTENDING DOWN THROUGH THE NORTHERN AND CENTRAL ROCKIES WITH A
WEAK RIDGE OF HIGH PRESSURE POSITIONED ACROSS THE PACIFIC
NORTHWEST. A MID TO UPPER LEVEL LOW IS LOCATED FARTHER NORTHWEST
ACROSS THE EASTERN PACIFIC OCEAN. AN AREA OF LOW PRESSURE BECOMES
PRESENT CLOSER TO THE SURFACE WITH A COLD FRONT EXTENDING FROM
IOWA THROUGH NORTHWEST KANSAS AND INTO SOUTHERN COLORADO. WINDS
ARE GENERALLY LIGHT AND VARIABLE AND ALLOWING LOW LEVEL MOISTURE TO
POOL UP AGAINST THIS FRONT. THIS IS ALLOWING LOW CLOUDS AND FOG
TO DEVELOP ACROSS PARTS OF WESTERN KANSAS. TEMPERATURES ACROSS
SOUTHWEST KANSAS CURRENTLY RANGE FROM THE LOWER 40S ACROSS WEST
CENTRAL KANSAS WITH UPPER 40S AND LOWER 50S ELSEWHERE.
&&
.UPDATE...
ISSUED AT 545 PM CST WED FEB 6 2013
THE LATEST HIGH RESOLUTION NAM WRF CORES AND THE RAPID REFRESH ARE
STRONGLY SUGGESTING THE RAPID ONSET OF DENSE FOG DEVELOPMENT THIS
EVENING. THE MODELS ARE PROBABLY DOING A BETTER JOB THAN THE LOCAL
GFS MOS AT THIS TIME, WHICH APPEARS TOO FOCUSED ON TYPICAL DIURNAL
TRENDS. WITH LOW 50`S DEW POINTS INCREASING THIS EVENING, AND
BACKING SURFACE WINDS CREATING WEAK UPSLOPE AHEAD OF AN ADVANCING
COLD FRONT FROM NORTHWEST KANSAS, FOG COULD START TO DEVELOP FROM
DIGHTON TO GARDEN CITY BY MID EVENING. A DENSE FOG ADVISORY WAS
HOISTED FROM GENERALLY THE HIGHWAY 83 CORRIDOR EASTWARD FROM 4 TO 12
UTC THURSDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 236 PM CST WED FEB 6 2013
TONIGHT:
SEVERAL SENSIBLE WEATHER IMPACTS EXPECTED TONIGHT INTO TOMORROW MORNING.
FIRST IS FOG. HRRR IS VERY AGGRESSIVE IN DEVELOPING LOW VISIBILITIES
AFTER 00Z TONIGHT. THE NAM AND ARW-WRF IS NOT AS AGGRESSIVE WITH FOG.
DUE TO THE WARM AIR ADVECTION PATTERN THAT IS CURRENTLY TAKING PLACE
AND THE HIGHER DEWPOINTS ADVECTING IN ACROSS THE REGION...WILL GO WITH
PATCHY FOG TONIGHT ALONG AND EAST OF HIGHWAY 283 WITH AREAS OF FOG
ALONG SOUTH CENTRAL KANSAS WHERE DEWPOINTS ARE HIGHER. THE NEXT CONCERN
IS CONVECTION. THE BEST CHANCE FOR OVERNIGHT THUNDERSTORMS IS GENERALLY
ALONG AND EAST OF HIGHWAY 183. HERE WARM AIR ADVECTION...ISENTROPIC
LIFT ALONG THE 295 KELVIN THETA SURFACE... AND INCREASING 850-650 HPA
FRONTOGENESIS SHOULD INITIATE CONVECTIVE ACTIVITY AFTER 03Z TONIGHT.
ALL THE MESOSCALE MODELS SUGGESTS THIS AS WELL AS THE GFS AND ECMWF.
SEVERE THUNDERSTORMS ARE NOT EXPECTED DUE TO WEAK THERMODYNAMICS AND
WEAK KINEMATICS. CONVECTION SHOULD BE CLEAR OF THE REGION BY DAWN.
A DENSE FOG ADVISORY COULD BE NEEDED FOR TOMORROW MORNING, BUT DO NOT
HAVE ENOUGH CONFIDENCE TO ISSUE ONE THIS EARLY.
TOMORROW:
TOMORROW MORNING WILL BE BREEZY AS THERE WILL BE A TIGHT PRESSURE GRADIENT
ACROSS THE REGION ALONG WITH 45 KT 850 HPA WINDS PARTIALLY MIXING DOWN.
NOT EXPECTING WIND ADVISORY LEVELS AT THIS TIME. OTHER THAN SOME POSSIBLE
LINGERING FOG, TOMORROW WILL BE FAIRLY QUIET WITH CLEARING SKIES. HIGHS
SHOULD BE IN THE 50S DEG F. WINDS SHOULD ABATE AS THE DAY WEARS ON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 PM CST WED FEB 6 2013
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
MOVING EASTWARD ACROSS THE CENTRAL PLAINS FRIDAY RESULTING IN DRY
CONDITIONS ACROSS WESTERN KANSAS THROUGH FRIDAY NIGHT. MEANWHILE,
A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE IS EXPECTED TO DIG
SOUTHEAST INTO THE GREAT BASIN REGION FRIDAY, THEN TURN EASTWARD
MOVING INTO THE CENTRAL AND SOUTHERN ROCKIES SATURDAY BRINGING THE
POSSIBILITY FOR SHOWERS AND THUNDERSTORMS TO PORTIONS OF WESTERN
KANSAS AS EARLY AS SATURDAY AFTERNOON. A RETURN FLOW WILL SET UP
EARLY FRIDAY DRAWING GULF MOISTURE NORTHWARD INTO MUCH OF KANSAS
WITH H85 DEWPOINTS CLIMBING JUST ABOVE 0C. ADDITIONALLY, SURFACE
LOW PRESSURE IN EASTERN COLORADO WILL STRENGTHEN THROUGHOUT THE
DAY WITH A SHARPENING DRYLINE EXTENDING SOUTHWARD GENERALLY INTO
THE TEXAS PANHANDLE. DYNAMIC SUPPORT ALOFT WILL BECOME MORE
FAVORABLE AS WELL WITH THE GFS AND ECMWF SHOWING A STRONG H5 VORT
MAX LIFTING NORTHEAST OUT OF THE TROUGH AXIS AND ACROSS THE
WESTERN HIGH PLAINS SATURDAY NIGHT. A +100KT UPPER LEVEL JET WILL
ALSO BE STREAMING EAST-NORTHEAST ACROSS WEST TEXAS AND THE TEXAS
PANHANDLE INTO THE PLAINS OF WESTERN OKLAHOMA AND SOUTHERN KANSAS
LATE SATURDAY. AS A RESULT, SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP ACROSS THE SOUTH PLAINS SATURDAY AFTERNOON AND EVENING,
LIFTING NORTHEASTWARD INTO CENTRAL KANSAS WITH CHANCES FOR THE
PRECIP DWINDLING TOWARD THE WEST. GFS AND ECMWF MODEL SOUNDINGS
INDICATE A REAL LACK OF INSTABILITY LIMITING SEVERE POTENTIAL.
ANY PRECIP WILL LIKELY COME TO AN END BY MID DAY SUNDAY AS THE
UPPER LEVEL TROUGH BEGINS TO LIFT NORTHEAST INTO THE UPPER
MIDWEST.
TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL FRIDAY EVEN AS SURFACE
HIGH PRESSURE MOVES FROM THE NORTHERN PLAINS SOUTHEAST INTO THE
UPPER MIDWEST. THIS WILL TURN WINDS SOUTH TO SOUTHEASTERLY ACROSS
WESTERN KANSAS THROUGHOUT MUCH OF THE DAY. HOWEVER, THIS WILL DO
LITTLE TO ERODE THE COOLER AIR MASS THAT IS PROJECTED TO SINK
SOUTH INTO WESTERN KANSAS BEHIND A PASSING COLD FRONT THURSDAY.
THE NAM, GFS, AND ECMWF SHOW H85 TEMPERATURES RANGING FROM JUST
ABOVE 0C ACROSS CENTRAL KANSAS TO JUST ABOVE 5C ALONG THE COLORADO
BORDER. LOOK FOR HIGHS WELL UP INTO THE 50S(F) FRIDAY AFTERNOON.
SIMILAR HIGHS ARE LIKELY SATURDAY AS SURFACE LOW PRESSURE
STRENGTHENS ACROSS EASTERN COLORADO KEEPING SOUTHERLY WINDS IN
PLACE ACROSS WESTERN KANSAS. A COLD FRONT PUSHING THROUGH WESTERN
KANSAS SUNDAY WILL ALLOW COLDER AIR TO SURGE SOUTHWARD INTO
WESTERN KANSAS RESULTING IN LOWER HIGH TEMPERATURES. OVERALL,
TEMPERATURES ARE LIKELY TO REMAIN BELOW NORMAL THROUGH MID WEEK AS
A SECONDARY UPPER LEVEL TROUGH DEVELOPS ACROSS THE INTERMOUNTAIN
WEST AND MOVES INTO THE WESTERN HIGH PLAINS DRAWING MORE COLDER
DOWN INTO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 531 PM CST WED FEB 6 2013
THE MAJOR IMPACT TO AVIATION WILL BE DENSE FOG DEVELOPMENT LATE
THIS EVENING AND LASTING THROUGH THE OVERNIGHT. INCREASING LOW
LEVEL MOISTURE AHEAD OF A SURFACE COLD FRONT WILL PROVIDE THE
CONDITIONS FOR ADVECTION FOG ACROSS MUCH OF CENTRAL ANS SOUTHWEST
KANSAS BEGINNING AS EARLY AS 03 UTC. THE LATEST MESOSCALE MODELS
INCLUDING THE VARIOUS NAM ARW CORES AND THE RAPID REFRESH ARE ALL
STRONGLY SUGGESTING DENSE FOG DEVELOPMENT. IT IS BELIEVED THE LOCAL
GFS MOS (LAMP) IS TOO FOCUSED ON NORMAL DIURNAL TRENDS AND LIKELY
INCORRECT. A 700 MB WAVE WILL HELP SET OFF SHOWERS AND ISOLATED
THUNDERSTORM ACROSS CENTRAL KANSAS AS WELL, PROBABLY JUST EAST OF
HAYS AND DODGE CITY BETWEEN MID NIGHT AND 10Z. AT THIS TIME, TEMPO
1/4SM CONDITIONS WILL BE CARRIE UNTIL SUCH CONFIDENCE THAT
PREVAILING CONDITIONS CAN BE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 54 27 56 / 10 0 0 0
GCK 36 53 27 56 / 0 0 0 0
EHA 34 51 27 57 / 0 0 0 0
LBL 37 53 27 57 / 0 0 0 0
HYS 39 53 25 55 / 40 0 0 0
P28 48 55 30 56 / 80 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM CST THURSDAY FOR KSZ030-031-
043>046-063>066-076>081-086>090.
&&
$$
UPDATE...RUSSELL
SYNOPSIS...HOVORKA_42
SHORT TERM...SUGDEN
LONG TERM...JJOHNSON
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
204 AM EST THU FEB 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST OF THE AREA TODAY. A LOW PRESSURE
SYSTEM WILL APPROACH FROM THE WEST TONIGHT AND BRING A MIX OF
RAIN AND SNOW TO THE AREA AS IT CROSSES THE AREA ON FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST AND ALLOW FOR A DRY
WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AN ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST TRENDS IN TEMP AND SKY. WINDS WERE ALSO INCREASED
FOR THIS EVENING IN THE DOWNSLOPE AREAS OF THE WEST-FACING SLOPES
OF CHESTNUT/LAUREL RIDGES.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A
ZONAL FLOW WITH 500MB MOISTURE BEGINNING TO ADVECT INTO THE AREA
FROM THE WEST. AT THE SURFACE...A 1030MB HIGH IS CENTERED OVER THE
JERSEY COAST...WITH A BROAD AREA OF HIGH PRESSURE EXPANDING WESTWARD
INTO THE AREA. INFRARED SAT IMAGERY INDICATES CLEAR SKIES GIVING
WAY TO UPPER LEVEL CLOUD COVERAGE THAT IS ENCROACHING THE AREA FROM
THE SOUTHWEST.
TODAY...THE SURFACE HIGH WILL CONTINUE TO SHIFT EAST OF THE AREA.
MEANWHILE...FURTHER UPSTREAM...AN INVERTED TROUGH OF LOW PRESSURE
WILL SLIDE INTO THE LOWER GREAT AS ANOTHER LOW DEVELOPS ACROSS THE
SOUTHERN PLAINS. 750-250MB LAYER MOISTURE ASSOCIATED WITH THIS
SYSTEM WILL SPILL INTO THE AREA...WITH SKIES BECOMING MOSTLY CLOUDY
BY THIS AFTERNOON. ALTHOUGH INCREASING CLOUDINESS WILL BE AN
INHIBITOR TO HEATING TODAY...WAA ADVECTION WILL ENSUE AS A LOW-LEVEL RIDGE
SHIFTS EAST OF THE AREA AND THE LOW-LEVEL FLOW BECOMES
SOUTHWESTERLY. A SOUTHEASTERLY FLOW WILL FAVOR DOWNSLOPE
ENHANCEMENT WITH WINDS BEGINNING TO PICK UP ON THE WEST-FACING
SLOPES BEGINNING THIS EVENING.
WITH WAA TODAY...TEMPS WILL WARM ABOVE FREEZING ACROSS THE ENTIRE
FORECAST AREA FOR THE FIRST TIME THIS MONTH. HIGHS ARE A MAV/MET
BLEND...RANGING FROM THE MID 30S ALONG THE I-80 CORRIDOR AND
LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE MID 40S IN PORTIONS OF
EASTERN OHIO AND NORTHERN WV.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS LOW PRESSURE TRACKS ACROSS THE GREAT LAKES EXPECT LIGHT
PRECIPITATION TO SPREAD ACROSS REGION AS THURSDAY NIGHT
PROGRESSES. MODEL THICKNESS AND 850MB TEMPS SHOW SNOW AT THE START
BUT AS FORECAST SOUNDINGS SHOW WARMING INTO FRIDAY MORNING EXPECT
A FAIRLY QUICK CHANGE TO RAIN ACROSS ALL BUT MOST NORTHERN
LOCATIONS.
FOR THE RIDGES EAST AND SOUTHEAST LOW LEVEL FLOW WILL BE SOUTHEAST
WHICH IS NOT A GREAT DIRECTION FOR COLD AIR DAMMING BUT MODELS DO
KEEP COLD LOW LEVELS ALONG AND EAST OF THE HIGHEST SLOPES LATER
THURSDAY NIGHT AND FRIDAY MORNING. QUESTION IS IF ANY
PRECIPITATION WILL OCCUR AS ONLY EASTERLY UPSLOPE SEEMS TO BE
DRIVER OF ANY POSSIBLE FREEZING RAIN OR DRIZZLE. HAVE LEFT THIS
CHANCE IN FORECAST AND LATER SHIFTS MAY BE ABLE TO PIN THIS DOWN
FURTHER.
OTHERWISE AS PARENT SYSTEM MOVES TO THE EASTERN LAKES FAST
DEVELOPING COASTAL LOW WILL BE NEAR THE CAROLINA COAST FRIDAY
MORNING. THESE SYSTEMS WILL PHASE OFF THE NEW ENGLAND COAST BY
FRIDAY EVENING AND TAKE DEEP MOISTURE WELL EAST OF REGION WITH COLD
AND DRY AIR PUSHING BACK SOUTHWARD FRIDAY NIGHT.
WITH FIRST LOW PRESSURE SYSTEM WEAKENING IN THE COASTAL STORMS
SHADOW FRIDAY NOT A GREAT DEAL OF QPF LEFT FOR OUR REGION. MIXED
RAIN AND SNOW FRIDAY AFTERNOON WILL SWITCH TO ALL SNOW LATE FRIDAY
AFTERNOON AND THEN QUICKLY END FRIDAY EVENING.
ALONG AND NORTH OF I-80 1 TO 3 INCHES OF SNOW POSSIBLE FROM
THURSDAY LATE NIGHT TO WHEN THE SNOW ENDS FRIDAY EVENING. AN INCH
POSSIBLE IN THE RIDGES WITH A COATING ELSEWHERE.
COLD ADVECTION FRIDAY NIGHT WILL DROP TEMPERATURES WELL INTO THE
TEENS AS 850MB TEMPS FALL BUT FLOW WILL BE BECOMING NORTH TO
NORTHEAST WITH LITTLE OR NO LAKE EFFECT.
BY SATURDAY COLD AND DRY HIGH PRESSURE WILL BRING SUNSHINE WITH BELOW
NORMAL TEMPERATURES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS HAVE BEEN CONSISTENT IN DVLPMNT OF SPLIT FLOW OVR THE CONUS
THIS WEEKEND WITH RIDGING OVR THE GREAT LAKES AND UPR OH REGIONS.
TEMP MODERATION THUS RMNS ON TRACK WITH READINGS APPROX 10 DEGREES
ABOVE THE AVERAGES FORECAST FOR THE BGNG OF THE NEW WEEK USING
TWEAKED ECMWF GUIDANCE AND PERSISTENCE. INITIALLY DRY WEATHER IS
EXPECTED TO DETERIORATE THOUGH AS LOW PRES DVLPS TWD THE GREAT LAKES.
HIGH AMPLITUDE CNTRL CONUS TROF IS PROGGED TO SLIDE EWD AS MID
WEEK APPROACHES...HENCE TEMPS SHOULD FADE BACK TWD THE SEASONAL
AVERAGES. HOWEVER...POPS WL BE DEPENDENT ON TIMING OF SHRTWVS
MOVING THROUGH THE SWLY FLOW ON THE ERN FLANK OF THAT TROF. HAVE
THUS FORECASTED LATE MON THRU WEDNESDAY POPS NR CHC CLIMO NMBRS
FOR NOW.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
CLEAR SKIES CAN BE EXPECTED OVERNIGHT WITH GENERAL VFR CONDITIONS.
SOME PATCHY FOG IS POSSIBLE...MAINLY AT KMGW AND KZZV. INCREASING
MIDDLE CLOUDS ARE FORECAST AFTER SUNRISE INTO THIS AFTERNOON. LIGHT
WINDS CAN BE EXPECTED THROUGH THE TAF PERIOD.
.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
LOW PRES AND THE ASSOCIATED CDFNT WILL DETERIORATE CONDITIONS ONCE
AGAIN FOR THURSDAY NIGHT AND FRIDAY. HIGH PRES WILL RETURN VFR FOR
THE WEEKEND. ANOTHER SYSTEM WILL BRING WIDESPREAD RESTRICTIONS
SUNDAY NIGHT INTO MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...RSD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
355 AM CST THU FEB 7 2013
.DISCUSSION...
CHALLENGING FORECAST TODAY WITH STRATUS SPREADING SOUTH AND
CAUSING POTENTIAL PROBLEMS WITH TEMPERATURE FORECAST... AND
CHALLENGING PRECIPITATION FORECAST FOR WEEKEND WITH STRONG LOW
MOVING THROUGH PLAINS.
CURRENT PATTERN AT THE SURFACE CONSISTED OF A WEAK COLD FRONT
THAT WAS ANALYZED AT 09Z ALMOST THROUGH THE SOUTHEAST CORNER OF
THE FORECAST AREA. WELL BEHIND THE FRONT IN SOUTH DAKOTA WAS AN
EXTENSIVE AREA OF LOW STRATUS...MOVING SOUTH AT AROUND 15 KNOTS.
SHORT TERM MODELS SHOW LITTLE AGREEMENT ON THE EVOLUTION OF THIS
AREA OF STRATUS. GENERALLY THE NAM AND GFS BRING IT INTO THE
FORECAST AREA BUT SUGGEST IT WILL ERODE BY AFTERNOON. HOWEVER THE
HIGHER RESOLUTION HRRR AND RAP ARE MUCH MORE PESSIMISTIC AND PUSH
THE STRATUS AS FAR SOUTH AS THE PLATTE RIVER BY 17Z AND SHOW IT
REMAINING. THIS OF COURSE HAS BIG IMPLICATIONS FOR THE TEMPERATURE
FORECAST. AT THIS TIME WE ARE MORE COMFORTABLE WITH A SOLUTION
CLOSER TO THE HRRR/RAP ESPECIALLY IN NORTHEAST NEBRASKA. THUS HAVE
LOWERED HIGH TEMPERATURES IN NORTHEAST NEBRASKA AND AND KEPT
CLOUDY WORDING THROUGH MUCH OF THE DAY.
TEMPERATURE/CLOUD UNCERTAINTY IS GREATEST FOR LOCATIONS ALONG
INTERSTATE 80 WHERE THE HRRR/RAP SHOW THE STRATUS JUST
APPROACHING. THIS AREA WILL NEED TO BE WATCHED THIS MORNING TO
MONITOR THE SOUTHWARD EXTENT OF THE CLOUD DECK AND THE NEW RUNS OF
THE HRRR AND RAP.
ON FRIDAY THE ATTENTION TURNS TO THE UPPER PATTERN PROGRESSING WITH
A STRONG UPPER LOW MOVING FROM THE WEST THROUGH THE ROCKIES AND
TAKING AIM ON THE PLAINS FOR THE WEEKEND. MODELS AGREE ON LEE SIDE
CYCLOGENESIS BY FRIDAY AFTERNOON AND SOUTH WINDS INCREASING BY
FRIDAY NIGHT. FRIDAY WILL BE DRY...WITH TEMPERATURES MILD AGAIN.
MOST MODELS SHOW DECENT AGREEMENT WITH THE UPPER LOW MOVING OUT OF
COLORADO SATURDAY NIGHT. SOUTHERLY 850 WINDS ARE PROGGED AS HIGH
AS 60 KNOTS OVER THE FORECAST AREA SATURDAY NIGHT AND SUNDAY
MORNING. LOW TEMPERATURES SATURDAY NIGHT WILL BE MILD...WITH
HUMIDITY INCREASING. VERTICAL MOTION AND MOISTURE WILL BE
SUFFICIENT TO TRIGGER SCATTERED SHOWERS ESPECIALLY NORTHERN HALF
OF FORECAST AREA. ON SUNDAY MORNING...THE DRY SLOT WILL BE PUSHING
NORTH THROUGH NEBRASKA. THIS PATTERN HAS THE APPEARANCE OF A
SPRING LOW TOPPED/COLD CORE THUNDERSTORM EVENT. TIGHTLY WRAPPED UP
SURFACE LOW IS PROGGED TO MOVE NEAR EASTERN NEBRASKA JUST EAST OF
CLOSED UPPER LOW...WITH MUCAPE VALUES OF 200-400 J/KG ALONG THE
EDGE OF THE DRY SLOT. CURRENTLY HAVE THUNDER MENTIONED IN FORECAST
AND WILL NEED TO MONITOR FOR ADDITIONAL DETAILS.
AS THE LOW MOVES NORTHEAST...COLD AIR MOVES IN WITH PRECIPITATION
CHANGING TO SNOW ESPECIALLY IN NORTHEAST NEBRASKA. SOME SCENARIOS
SUGGEST A FEW INCHES OF SNOW WITH NORTHWEST WINDS GUSTING TO 40
MPH GIVEN THE NORTHWEST 850 WINDS OF 50 KNOTS OVER FAR NORTHEAST
NEBRASKA. FORECAST COVERS THIS BUT WILL CONTINUE TO ADVERTISE THIS
POSSIBLE WINTER WEATHER EVENT IN HWO. MOST MODELS HAVE THE
PRECIPITATION ON SUNDAY ENDING AS THE LOW RAPIDLY MOVES
NORTHEAST...MEANING THE OMAHA-LINCOLN AREAS AND POINTS SOUTH WOULD
SEE LITTLE SNOW.
NIETFELD
&&
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK
SURFACE COLD FRONT HAS MOVED THROUGH OFK...AND WILL SOON MOVE
THROUGH OMA/LNK BY 07Z. THE SHOWERS HAVE DEVELOPED THIS
EVENING...BUT SOUTH OF THE TAF SITES AND THUS HAVE A DRY 24 HR
PERIOD IN THE TAFS CURRENTLY. CURRENTLY MID LEVEL CLOUDS AT OMA/LNK
WILL SHIFT SWD OVER THE NEXT FEW HOURS LEAVING JUST SOME HIGH LEVEL
CLOUDS UNTIL MORNING. IR IMAGERY INDICATES THAT STRATUS IS DIVING
SWD THROUGH ERN SD AND THIS SHOULD BE INTO OFK AROUND 12Z AND OMA
AROUND 14-15Z. THERE IS SOME QUESTION IF THIS WILL MAKE LNK AND WILL
JUST INCLUDE A TEMPO ATTM. THE STRATUS DECK...IN THE MVFR
RANGE...WILL LINGER AT OMA/OFK THROUGH EARLY-MID AFTN. WE WILL ALSO
SEE WINDS INCREASE THROUGH THE MORNING AT ALL SITES WITH SOME GUSTS
LIKELY. THE WINDS AND CLOUDS WILL DIMINISH BY LATE AFTN.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1059 PM CST WED FEB 6 2013
.AVIATION...06Z KGRI TAF. A COLD FRONT HAS PASSED THROUGH KGRI
AND THE WIND WILL NOW BE NORTHERLY THROUGHOUT THE DAY ON THURSDAY.
EXPECT THE THE NORTH WIND WILL INCREASE BY MID MORNING BECOMING
BREEZY AT TIMES THROUGH MID AFTERNOON. CLOUDS WILL ALSO ACCOMPANY
THE COLD FRONT WITH CLOUDY TO MOSTLY CLOUDY SKIES THROUGH MUCH OF
THE NIGHT UNTIL AROUND MID MORNING. HOWEVER...ANY CLOUDS APPEAR TO
BE WITHIN THE VFR CATEGORY. CLOUDS SHOULD CLEAR OUT BY LATER THIS
MORNING WITH CLEAR TO MOSTLY CLEAR SKIES EXPECTED BY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1017 PM CST WED FEB 6 2013/
UPDATE...FOG HAS FORMED WHERE MOISTURE HAS POOLED JUST AHEAD OF
THE COLD FRONT AND WHERE THE WIND IS LIGHT. THIS FOG HAS BEEN
LOCALLY DENSE BUT ALSO FAIRLY SHALLOW. THE FOG WILL QUICKLY ERODE
AWAY FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA AS THE
COLD FRONT SWEEPS THROUGH AND KICKS UP THE NORTH WIND. WILL
CONTINUE TO BE CALLING FOR DRY WEATHER ACROSS MOST OF OUR CWA
TONIGHT...AND HAVE EVEN REDUCED THE LOW POPS WE DID HAVE ACROSS
OUR FAR SOUTHEAST CWA AS LATEST 00Z RUC AND NAM MODEL RUNS KEEP
ALL THE THUNDERSTORMS SOUTHEAST OF OUR FORECAST AREA TONIGHT.
THEREFORE...HAVE ALSO PULLED THUNDER OUT OF THE FORECAST AND HWO
FOR OUR CWA...ALTHOUGH THE STORMS MAY NOT BE TOO FAR AWAY ONCE THEY
DEVELOP ON THE LOW LEVEL JET LATER TONIGHT JUST TO THE SOUTH OF
OUR CWA.
PREV DISCUSSION... /ISSUED 413 PM CST WED FEB 6 2013/
SHORT TERM...THROUGH THURSDAY AFTERNOON. MORNING UPPER AIR ANALYSIS
INDICATES A LONGWAVE TROUGH OVER THE NORTHEASTERN CONUS...WITH
QUASI-ZONAL FLOW OVER THE REMAINDER OF THE CONUS. MID AND UPPER
TROPOSPHERIC JET ENERGY EXTENDS FROM SOUTH CENTRAL
CANADA...SOUTHEAST INTO THE GREAT LAKES REGION AND THEN
EAST/NORTHEAST INTO EASTERN CANADA. TROPOSPHERIC FLOW OVER OUR
AREA IS NOT OVERLY STRONG...MAXING OUT AT AROUND 65KTS NEAR 200MB
PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES A
MID LEVEL SHORT WAVE OVER THE SOUTHERN PLAINS...WITH ANOTHER SHORT
WAVE ADVANCING EAST ACROSS THE NORTHERN AND CENTRAL ROCKY MOUNTAIN
RANGE. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE EXISTS
OVER SOUTHEASTERN COLORADO...WITH A STATIONARY BOUNDARY EXTENDING
NORTHEAST FROM THE LOW ACROSS PORTIONS OF NORTHEASTERN COLORADO
AND WESTERN NEBRASKA. OUR CWA STILL REMAINS AHEAD OF THE LOW LEVEL
BAROCLINIC ZONE AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS
OUR AREA REMAINS FROM THE SOUTH/SOUTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN ALL
SUGGEST THE MID LEVEL SHORT WAVE...CURRENTLY OVER THE NORTHERN AND
CENTRAL ROCKY MOUNTAIN RANGE...WILL CONTINUE MOVING EAST ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE NEXT 24 HOURS. OMEGA AHEAD
OF THE MID LEVEL TROUGH AXIS DOES NOT LOOK ALL THAT IMPRESSIVE. THAT
BEING SAID...WHAT OMEGA WILL BE IN PLACE TONIGHT...WORKING IN
CONCERT WITH MODEST LOW LEVEL CONVERGENCE NEAR THE BAROCLINIC
ZONE...MAY PROVIDE ENOUGH LIFT FOR PRECIPITATION PRODUCTION ACROSS
SOUTHERN AND EASTERN PORTIONS OF OUR CWA TONIGHT...A SOLUTION
SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC...AND
SREF-MEAN. WENT AHEAD AND MAINTAINED SLIGHT CHANCE TO CHANCE POPS
ACROSS OUR SOUTH AND EAST FOR TONIGHT AS A RESULT. FORECAST
PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND
OPERATIONAL GFS...SUGGEST THE LOWER TROPOSPHERE SHOULD REMAIN WARM
ENOUGH FOR RAIN THROUGH THE OVERNIGHT HOURS. IN ADDITION TO THE
CHANCE FOR PRECIPITATION...THE NAM...OPERATIONAL GFS...AND EC ALL
SUGGEST DEEP LAYER MUCAPE VALUES BETWEEN 50 AND 100J/KG WILL BE
REALIZED ACROSS OUR EXTREME SOUTHEAST BY 06Z TONIGHT. GIVEN
THIS...WENT AHEAD AND INCLUDED ISOLATED THUNDER MENTION IN THE
GRIDS FOR TONIGHT...PRIMARILY FOR LOCATIONS SOUTHEAST OF A LINE
FROM OSBORNE TO HEBRON. THE LOW LEVEL BAROCLINIC ZONE IS EXPECTED
TO CLEAR OUR ENTIRE CWA BY 09Z TONIGHT...WITH THE MID LEVEL TROUGH
AXIS EXPECTED TO CLEAR OUR AREA BY LATE MORNING THURSDAY. WITH THE
PRIMARY AXIS OF OMEGA PUSHING EAST OF OUR AREA DURING THE DAY
THURSDAY...DRY CONDITIONS LOOK TO OVERTAKE OUR AREA HEADING INTO
THURSDAY.
OVERNIGHT LOWS GENERALLY IN THE 30S ARE EXPECTED ACROSS THE AREA
TONIGHT. WITH LOW LEVEL COLD AIR ADVECTION INFILTRATING THE AREA
TONIGHT BEHIND THE BAROCLINIC ZONE...SLIGHTLY COOLER WEATHER SHOULD
BE OBSERVED THURSDAY WHEN COMPARED TODAY...WITH HIGHS IN THE UPPER
40S TO LOWER 50S CURRENTLY FORECAST FOR MOST LOCATIONS ACROSS THE CWA.
LONG TERM...THURSDAY EVENING THROUGH NEXT WEDNESDAY. CLEARLY THE
MAIN FOCUS REMAINS THE 72-HOUR BLOCK OF TIME BETWEEN FRIDAY AND
SUNDAY NIGHT...INVOLVING THE APPROACH AND PASSAGE OF A STRONG LOW
PRESSURE SYSTEM...AND A VARIETY OF WEATHER ELEMENTS INCLUDING
POTENTIALLY ADVISORY-CRITERIA WINDS BOTH AHEAD OF AND BEHIND THE
MAIN SURFACE LOW...GENERALLY WEAK THUNDERSTORM ACTIVITY MAINLY
SATURDAY NIGHT....AND THEN THE CHANGEOVER TO SNOW/BLOWING SNOW
SOMETIME BETWEEN LATE SATURDAY NIGHT AND SUNDAY BEFORE ALL PRECIP
PULLS OUT OF THE AREA BY SUNDAY EVENING. ALTHOUGH THE LATEST 12Z
MODEL RUNS ARE STARTING TO ADD A BIT MORE CONFIDENCE THAT THE
BRUNT OF THE SNOW WILL JUST MISS OUR CWA TO THE NORTHWEST...THERE
COULD STILL BE PLENTY OF ISSUES ESPECIALLY IN OUR NORTHWEST
COUNTIES...NOT TO MENTION THAT STILL BEING 4 DAYS AWAY CHANGES IN
THE TRACK OF THE SYSTEM ARE STILL POSSIBLE.
STARTING OUT WITH THURSDAY EVENING THROUGH FRIDAY
NIGHT...CONFIDENCE REMAINS HIGH IN DRY WEATHER...AS FLOW ALOFT
GRADUALLY TRANSITIONS FROM WEST-NORTHWEST BEHIND THE SHORTWAVE
DEPARTING ACROSS IA/IL/IN...TO SOUTHWEST FLOW AHEAD OF THE
LARGER...DEEPER TROUGH ORGANIZING OVER THE SOUTHWEST CONUS. ON
THURSDAY NIGHT...LIGHT BREEZES WILL GRADUALLY TRANSITION FROM
EASTERLY TO SOUTHERLY UNDER MOSTLY CLEAR SKIES. LOW TEMPS WERE
LOWERED A FEW DEGREES FROM PREVIOUS FORECAST...BUT STILL REMAINING
A FEW DEGREES ABOVE MET/MAV GUIDANCE BLEND...RESULTING IN MID 20S
MOST AREAS. FRIDAY...SKIES REMAIN MOSTLY SUNNY OVERALL...BUT
SOUTH-SOUTHEAST WINDS WILL BE ON THE INCREASE IN RESPONSE TO HIGH
PLAINS PRESSURE FALLS AND GOOD MIXING. UPPED WINDS A FEW MPH FROM
PREVIOUS FORECAST...WITH SUSTAINED SPEEDS 20-25 MPH IN MOST
AREAS...AND MORE SO 25-30 MPH IN OUR FAR WESTERN AREAS FROM DAWSON
THROUGH FURNAS COUNTIES. AT LEAST FOR NOW...THESE SPEEDS REMAIN
SLIGHTLY BELOW ADVISORY CRITERIA BUT IT BEARS WATCHING. NUDGED DOWN
HIGH TEMPS VERY SLIGHTLY DOWNWARD...RANGING FROM RIGHT AROUND 50
IN EASTERN ZONES...TO MID 50S SOUTHWEST. FRIDAY NIGHT...IT
REMAINS DRY AS THE PRIMARY MID LEVEL LOW CIRCULATION OVER THE
WESTERN CONUS EDGES NO CLOSER THAN THE UT/AZ/SOUTHWEST WY
AREA...BUT STEADY SOUTHERLY BREEZES WILL CONTINUE...LIKELY
RESULTING IN A RATHER MILD NIGHT. KEPT LOWS SIMILAR TO PREVIOUS
FORECAST WITH MOST AREAS HOLDING UP IN THE 32-36 RANGE...AND EVEN
THIS MIGHT NOT BE MILD ENOUGH GIVEN RECENT OVERNIGHT TRENDS.
FOCUSING NOW ON THE SATURDAY THROUGH SUNDAY NIGHT TIME FRAME...12Z
RUNS OF THE ECMWF/GFS/CANADIAN GEM ARE IN MUCH BETTER OVERALL
AGREEMENT THAN 24 HOURS AGO IN THE TRACK OF THE CLOSED 500MB
CIRCULATION...ALTHOUGH SOME SLIGHT TIMING DIFFERENCES DO EXIST.
GENERALLY SPEAKING...BY LATE SATURDAY AFTERNOON THE PRIMARY/STRONG
AND NEARLY VERTICALLY STACKED LOW PRESSURE CENTER WILL BE IN
EASTERN COLORADO...THEN REACHING THE HEART OF SOUTH CENTRAL NEB BY
SUNRISE SUNDAY MORNING...AND THEN THE WESTERN IA/POSSIBLY
SOUTHWEST MN AREA BY SUNDAY EVENING. GIVEN THAT THE SURFACE LOW IS
PROGGED TO TRACK ACROSS THE HEART OF THE CWA FROM SOUTHWEST-
NORTHEAST DURING THIS TIME...THE MOST INTENSE MID LEVEL
CONVERGENCE/DEFORMATION FOR HEAVY SNOW NOW LOOKS TO FOCUS JUST TO
OUR NORTHWEST ACROSS THE NEBRASKA SANDHILLS OF THE WFO LBF CWA.
HOWEVER...UNLESS THIS TRACK SHIFTS EVEN FARTHER NORTH...WE ARE
STILL PRONE TO SOME IMPACTS. BACKING UP TO SATURDAY DAYTIME...HAVE
INCREASING CONFIDENCE THAT THE MORNING HOURS WILL BE DRY...AND
HAVE PULLED PRECIP MENTION BEFORE NOON...WITH ONLY SLIGHT CHANCES
FOR RAIN SHOWERS IN THE AFTERNOON AS LOW LEVEL MOISTURE ADVECTION
GETS GOING. OVERALL THOUGH...WOULD NOT BE SURPRISED IF THE
MAJORITY OF THE CWA MAKES IT THROUGH THE DAY WITHOUT SEEING MORE
THAN SPRINKLES. AS FOR TEMPS...SHOULD STILL BE MILD WITH HIGHS
AROUND 50 NEARLY ALL AREAS...UNLESS LOW CLOUDS MOVE IN QUICKLY
ENOUGH TO HOLD THINGS DOWN A BIT. SOUTH-SOUTHEAST WINDS WILL ALSO
REMAIN FAIRLY STRONG ON SATURDAY...AND COULD POSSIBLY AGAIN FLIRT
WITH ADVISORY CRITERIA ALTHOUGH CURRENT FORECAST ONLY HAS
SUSTAINED SPEEDS TOPPING OUT 20-25 MPH. FOR SATURDAY NIGHT...THE
BIGGEST CHANGES FROM PREVIOUS FORECAST WERE TO INTRODUCE A SLIGHT
CHANCE OF THUNDERSTORMS ALONG WITH FAIRLY WIDESPREAD RAIN
SHOWERS...AND ALSO TO CONFINE ANY SNOW POTENTIAL TO ONLY THE FAR
WESTERN SOUTH CENTRAL NEBRASKA COUNTIES WELL AFTER MIDNIGHT.
CERTAINLY FOR THE VAST MAJORITY OF THE CWA...PRECIP TYPE IS NOW
EXPECTED TO REMAIN RAIN THROUGH THE NIGHT...WITH SOME AREAS
POSSIBLY SEEING A FEW TENTHS OF INCH AND LOCALLY HIGHER. ALTHOUGH
AT LEAST A FEW WEAK THUNDERSTORMS ARE A GOOD BET GIVEN WEAK
ELEVATED INSTABILITY AND THE STRENGTH OF THE UPPER WAVE...NOT
EXPECTING ANYTHING ALL THAT STRONG ALTHOUGH SUPPOSE IT WOULDN/T
TAKE MUCH TO GET PEA SIZE HAIL. SUNDAY DAYTIME...A STRONG COLD
FRONT SWEEPS ACROSS THE CWA AS THE LOW PASSES EAST...CHANGING ANY
RAIN TO SNOW...AND ALTHOUGH NOT EXPLICITLY REFLECTED IN THE OFFICIAL
GRIDS YET...SUSTAINED SPEED OF 30+ MPH ARE VERY MUCH POSSIBLE
GIVEN THE STRENGTH OF THE LOW LEVEL PRESSURE GRADIENT. WHILE POPS
WERE REDUCED DURING THE DAY ACROSS SOUTHERN ZONES AS THE MID LEVEL
DRY SLOT DOMINATES THIS AREA...NORTHWEST ZONES ESPECIALLY
NORTHWEST OF A BEAVER CITY-GRAND ISLAND-FULLERTON LINE ARE STILL
IN LINE TO POSSIBLY RECEIVE 2+ INCHES OF WIND-BLOWN SNOW. EVEN
ASSUMING THAT THE HEAVIEST SNOW AMOUNTS MISS OUR CWA TO THE
NORTHWEST...THE COMBINATION OF SNOW AND WIND IN OUR NORTHWEST
ZONES COULD STILL ULTIMATELY PROVE WORTHY OF A WINTER WEATHER
ADVISORY...ALTHOUGH WE ARE STILL SEVERAL DAYS AWAY FROM MAKING
FORMAL DECISIONS ON HEADLINES AND PLENTY IS SUBJECT TO CHANGE.
MEANWHILE...ROUGHLY THE SOUTHEAST HALF OF THE CWA INCLUDING KS
ZONES COULD ULTIMATELY SEE VERY LITTLE...IF ANY SNOW. ALTHOUGH
SOME LIGHT SNOW/FLURRIES COULD LINGER MAINLY IN NORTHEAST COUNTIES
SUNDAY EVENING...THE CURRENT TIMING SUGGESTS THAT THIS PRECIP
EVENT SHOULD BE OVER BY MIDNIGHT SUNDAY NIGHT. TEMP-WISE...HIGHS
ON SUNDAY ARE VERY TRICKY...AS TEMPS WILL LIKELY FALL VERY QUICKLY
BEHIND THE SHARP COLD FRONT. AT LEAST FOR NOW THOUGH...ANTICIPATE
READINGS AT SOME POINT DURING THE DAY TO REACH THE MID 30S
WEST...NEAR 40 CENTRAL AND MID 40S SOUTHEAST BEFORE THE COLDER AIR
BLASTS IN.
GETTING BEYOND THE MAIN SYSTEM OF INTEREST...THE MONDAY THROUGH
WEDNESDAY TIME FRAME IS PRECIPITATION-FREE AT THIS TIME...AND
CONFIDENCE REMAINS REASONABLY HIGH FOR THE DAY 5-7 TIME RANGE THAT
IT WILL REMAIN SO. ON MONDAY/MONDAY NIGHT...THE INITIAL CLOSED LOW
THAT BRINGS THE WEEKEND WEATHER WILL ALREADY PASS WELL OFF TO THE
NORTHEAST...WHILE A SECONDARY VORT MAX REMAINS WELL TO OUR
SOUTHWEST PRIMARILY TRACKING THROUGH THE SOUTHERN ROCKIES. FORCING
FOR PRECIP PRODUCTION FROM THIS SECONDARY WAVE SHOULD STAY
SOUTHWEST OF THE CWA. FROM TUESDAY INTO TUESDAY NIGHT...A FEW MORE
QUESTIONS ARISE AS THIS SOUTHWESTERN SHORTWAVE TROUGH HEADS EAST
ACROSS THE SOUTHERN PLAINS. THE LATEST GFS SOLUTION ACTUALLY TAGS
OUR FAR SOUTHERN CWA IN NORTH CENTRAL KS WITH SOME SNOW FROM THIS
WAVE...BUT THE ECWMF FOCUSES PRECIP NO CLOSER THAN THE KS/OK
BORDER...AND THE CURRENT FORECAST LEANS TOWARD THIS SOLUTION. BY
WEDNESDAY...MODELS ADVERTISE DRY NORTHWEST FLOW ALOFT IN THE WAKE
OF THE DEPARTING SOUTHERN STREAM WAVE. TEMP-WISE MONDAY THROUGH
WEDNESDAY...FOLLOWED ALLBLEND MODEL CONSENSUS WITH HIGHS GRADUALLY
REBOUNDING FROM THE LOW-MID 30S TO THE LOW-MID 40S...WITH FAR
NORTHERN AREAS POSSIBLY STAYING IN THE 20S ON MONDAY ESPECIALLY IF
A FEW INCHES OF SNOW DO MATERIALIZE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1017 PM CST WED FEB 6 2013
.UPDATE...FOG HAS FORMED WHERE MOISTURE HAS POOLED JUST AHEAD OF
THE COLD FRONT AND WHERE THE WIND IS LIGHT. THIS FOG HAS BEEN
LOCALLY DENSE BUT ALSO FAIRLY SHALLOW. THE FOG WILL QUICKLY ERODE
AWAY FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA AS THE
COLD FRONT SWEEPS THROUGH AND KICKS UP THE NORTH WIND. WILL
CONTINUE TO BE CALLING FOR DRY WEATHER ACROSS MOST OF OUR CWA
TONIGHT...AND HAVE EVEN REDUCED THE LOW POPS WE DID HAVE ACROSS
OUR FAR SOUTHEAST CWA AS LATEST 00Z RUC AND NAM MODEL RUNS KEEP
ALL THE THUNDERSTORMS SOUTHEAST OF OUR FORECAST AREA TONIGHT.
THEREFORE...HAVE ALSO PULLED THUNDER OUT OF THE FORECAST AND HWO
FOR OUR CWA...ALTHOUGH THE STORMS MAY NOT BE TOO FAR AWAY ONCE THEY
DEVELOP ON THE LOW LEVEL JET LATER TONIGHT JUST TO THE SOUTH OF
OUR CWA.
&&
.PREV DISCUSSION... /ISSUED 532 PM CST WED FEB 6 2013/
AVIATION...00Z KGRI TAF. A LIGHT SOUTH WIND WILL CONTINUE THROUGH
MUCH OF THE EVENING...UNTIL A WEAK COLD FRONT PASSES THROUGH KGRI
JUST BEFORE MIDNIGHT. THE WIND WILL TURN NORTHERLY BEHIND THE COLD
FRONT AND BECOME A BIT BREEZY AT TIMES ESPECIALLY BY MID TO LATE
MORNING. CLOUDS WILL ALSO ACCOMPANY THE COLD FRONT WITH CLOUDY TO
MOSTLY CLOUDY SKIES THROUGH MUCH OF THE NIGHT UNTIL AROUND MID
MORNING. HOWEVER...ANY CLOUDS APPEAR TO BE WITHIN THE VFR
CATEGORY.
PREV DISCUSSION... /ISSUED 413 PM CST WED FEB 6 2013/
SHORT TERM...THROUGH THURSDAY AFTERNOON. MORNING UPPER AIR ANALYSIS
INDICATES A LONGWAVE TROUGH OVER THE NORTHEASTERN CONUS...WITH
QUASI-ZONAL FLOW OVER THE REMAINDER OF THE CONUS. MID AND UPPER
TROPOSPHERIC JET ENERGY EXTENDS FROM SOUTH CENTRAL
CANADA...SOUTHEAST INTO THE GREAT LAKES REGION AND THEN
EAST/NORTHEAST INTO EASTERN CANADA. TROPOSPHERIC FLOW OVER OUR
AREA IS NOT OVERLY STRONG...MAXING OUT AT AROUND 65KTS NEAR 200MB
PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES A
MID LEVEL SHORT WAVE OVER THE SOUTHERN PLAINS...WITH ANOTHER SHORT
WAVE ADVANCING EAST ACROSS THE NORTHERN AND CENTRAL ROCKY MOUNTAIN
RANGE. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE EXISTS
OVER SOUTHEASTERN COLORADO...WITH A STATIONARY BOUNDARY EXTENDING
NORTHEAST FROM THE LOW ACROSS PORTIONS OF NORTHEASTERN COLORADO
AND WESTERN NEBRASKA. OUR CWA STILL REMAINS AHEAD OF THE LOW LEVEL
BAROCLINIC ZONE AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS
OUR AREA REMAINS FROM THE SOUTH/SOUTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...AND SREF-MEAN ALL
SUGGEST THE MID LEVEL SHORT WAVE...CURRENTLY OVER THE NORTHERN AND
CENTRAL ROCKY MOUNTAIN RANGE...WILL CONTINUE MOVING EAST ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE NEXT 24 HOURS. OMEGA AHEAD
OF THE MID LEVEL TROUGH AXIS DOES NOT LOOK ALL THAT IMPRESSIVE. THAT
BEING SAID...WHAT OMEGA WILL BE IN PLACE TONIGHT...WORKING IN
CONCERT WITH MODEST LOW LEVEL CONVERGENCE NEAR THE BAROCLINIC
ZONE...MAY PROVIDE ENOUGH LIFT FOR PRECIPITATION PRODUCTION ACROSS
SOUTHERN AND EASTERN PORTIONS OF OUR CWA TONIGHT...A SOLUTION
SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC...AND
SREF-MEAN. WENT AHEAD AND MAINTAINED SLIGHT CHANCE TO CHANCE POPS
ACROSS OUR SOUTH AND EAST FOR TONIGHT AS A RESULT. FORECAST
PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM AND
OPERATIONAL GFS...SUGGEST THE LOWER TROPOSPHERE SHOULD REMAIN WARM
ENOUGH FOR RAIN THROUGH THE OVERNIGHT HOURS. IN ADDITION TO THE
CHANCE FOR PRECIPITATION...THE NAM...OPERATIONAL GFS...AND EC ALL
SUGGEST DEEP LAYER MUCAPE VALUES BETWEEN 50 AND 100J/KG WILL BE
REALIZED ACROSS OUR EXTREME SOUTHEAST BY 06Z TONIGHT. GIVEN
THIS...WENT AHEAD AND INCLUDED ISOLATED THUNDER MENTION IN THE
GRIDS FOR TONIGHT...PRIMARILY FOR LOCATIONS SOUTHEAST OF A LINE
FROM OSBORNE TO HEBRON. THE LOW LEVEL BAROCLINIC ZONE IS EXPECTED
TO CLEAR OUR ENTIRE CWA BY 09Z TONIGHT...WITH THE MID LEVEL TROUGH
AXIS EXPECTED TO CLEAR OUR AREA BY LATE MORNING THURSDAY. WITH THE
PRIMARY AXIS OF OMEGA PUSHING EAST OF OUR AREA DURING THE DAY
THURSDAY...DRY CONDITIONS LOOK TO OVERTAKE OUR AREA HEADING INTO
THURSDAY.
OVERNIGHT LOWS GENERALLY IN THE 30S ARE EXPECTED ACROSS THE AREA
TONIGHT. WITH LOW LEVEL COLD AIR ADVECTION INFILTRATING THE AREA
TONIGHT BEHIND THE BAROCLINIC ZONE...SLIGHTLY COOLER WEATHER SHOULD
BE OBSERVED THURSDAY WHEN COMPARED TODAY...WITH HIGHS IN THE UPPER
40S TO LOWER 50S CURRENTLY FORECAST FOR MOST LOCATIONS ACROSS THE CWA.
LONG TERM...THURSDAY EVENING THROUGH NEXT WEDNESDAY. CLEARLY THE
MAIN FOCUS REMAINS THE 72-HOUR BLOCK OF TIME BETWEEN FRIDAY AND
SUNDAY NIGHT...INVOLVING THE APPROACH AND PASSAGE OF A STRONG LOW
PRESSURE SYSTEM...AND A VARIETY OF WEATHER ELEMENTS INCLUDING
POTENTIALLY ADVISORY-CRITERIA WINDS BOTH AHEAD OF AND BEHIND THE
MAIN SURFACE LOW...GENERALLY WEAK THUNDERSTORM ACTIVITY MAINLY
SATURDAY NIGHT....AND THEN THE CHANGEOVER TO SNOW/BLOWING SNOW
SOMETIME BETWEEN LATE SATURDAY NIGHT AND SUNDAY BEFORE ALL PRECIP
PULLS OUT OF THE AREA BY SUNDAY EVENING. ALTHOUGH THE LATEST 12Z
MODEL RUNS ARE STARTING TO ADD A BIT MORE CONFIDENCE THAT THE
BRUNT OF THE SNOW WILL JUST MISS OUR CWA TO THE NORTHWEST...THERE
COULD STILL BE PLENTY OF ISSUES ESPECIALLY IN OUR NORTHWEST
COUNTIES...NOT TO MENTION THAT STILL BEING 4 DAYS AWAY CHANGES IN
THE TRACK OF THE SYSTEM ARE STILL POSSIBLE.
STARTING OUT WITH THURSDAY EVENING THROUGH FRIDAY
NIGHT...CONFIDENCE REMAINS HIGH IN DRY WEATHER...AS FLOW ALOFT
GRADUALLY TRANSITIONS FROM WEST-NORTHWEST BEHIND THE SHORTWAVE
DEPARTING ACROSS IA/IL/IN...TO SOUTHWEST FLOW AHEAD OF THE
LARGER...DEEPER TROUGH ORGANIZING OVER THE SOUTHWEST CONUS. ON
THURSDAY NIGHT...LIGHT BREEZES WILL GRADUALLY TRANSITION FROM
EASTERLY TO SOUTHERLY UNDER MOSTLY CLEAR SKIES. LOW TEMPS WERE
LOWERED A FEW DEGREES FROM PREVIOUS FORECAST...BUT STILL REMAINING
A FEW DEGREES ABOVE MET/MAV GUIDANCE BLEND...RESULTING IN MID 20S
MOST AREAS. FRIDAY...SKIES REMAIN MOSTLY SUNNY OVERALL...BUT
SOUTH-SOUTHEAST WINDS WILL BE ON THE INCREASE IN RESPONSE TO HIGH
PLAINS PRESSURE FALLS AND GOOD MIXING. UPPED WINDS A FEW MPH FROM
PREVIOUS FORECAST...WITH SUSTAINED SPEEDS 20-25 MPH IN MOST
AREAS...AND MORE SO 25-30 MPH IN OUR FAR WESTERN AREAS FROM DAWSON
THROUGH FURNAS COUNTIES. AT LEAST FOR NOW...THESE SPEEDS REMAIN
SLIGHTLY BELOW ADVISORY CRITERIA BUT IT BEARS WATCHING. NUDGED DOWN
HIGH TEMPS VERY SLIGHTLY DOWNWARD...RANGING FROM RIGHT AROUND 50
IN EASTERN ZONES...TO MID 50S SOUTHWEST. FRIDAY NIGHT...IT
REMAINS DRY AS THE PRIMARY MID LEVEL LOW CIRCULATION OVER THE
WESTERN CONUS EDGES NO CLOSER THAN THE UT/AZ/SOUTHWEST WY
AREA...BUT STEADY SOUTHERLY BREEZES WILL CONTINUE...LIKELY
RESULTING IN A RATHER MILD NIGHT. KEPT LOWS SIMILAR TO PREVIOUS
FORECAST WITH MOST AREAS HOLDING UP IN THE 32-36 RANGE...AND EVEN
THIS MIGHT NOT BE MILD ENOUGH GIVEN RECENT OVERNIGHT TRENDS.
FOCUSING NOW ON THE SATURDAY THROUGH SUNDAY NIGHT TIME FRAME...12Z
RUNS OF THE ECMWF/GFS/CANADIAN GEM ARE IN MUCH BETTER OVERALL
AGREEMENT THAN 24 HOURS AGO IN THE TRACK OF THE CLOSED 500MB
CIRCULATION...ALTHOUGH SOME SLIGHT TIMING DIFFERENCES DO EXIST.
GENERALLY SPEAKING...BY LATE SATURDAY AFTERNOON THE PRIMARY/STRONG
AND NEARLY VERTICALLY STACKED LOW PRESSURE CENTER WILL BE IN
EASTERN COLORADO...THEN REACHING THE HEART OF SOUTH CENTRAL NEB BY
SUNRISE SUNDAY MORNING...AND THEN THE WESTERN IA/POSSIBLY
SOUTHWEST MN AREA BY SUNDAY EVENING. GIVEN THAT THE SURFACE LOW IS
PROGGED TO TRACK ACROSS THE HEART OF THE CWA FROM SOUTHWEST-
NORTHEAST DURING THIS TIME...THE MOST INTENSE MID LEVEL
CONVERGENCE/DEFORMATION FOR HEAVY SNOW NOW LOOKS TO FOCUS JUST TO
OUR NORTHWEST ACROSS THE NEBRASKA SANDHILLS OF THE WFO LBF CWA.
HOWEVER...UNLESS THIS TRACK SHIFTS EVEN FARTHER NORTH...WE ARE
STILL PRONE TO SOME IMPACTS. BACKING UP TO SATURDAY DAYTIME...HAVE
INCREASING CONFIDENCE THAT THE MORNING HOURS WILL BE DRY...AND
HAVE PULLED PRECIP MENTION BEFORE NOON...WITH ONLY SLIGHT CHANCES
FOR RAIN SHOWERS IN THE AFTERNOON AS LOW LEVEL MOISTURE ADVECTION
GETS GOING. OVERALL THOUGH...WOULD NOT BE SURPRISED IF THE
MAJORITY OF THE CWA MAKES IT THROUGH THE DAY WITHOUT SEEING MORE
THAN SPRINKLES. AS FOR TEMPS...SHOULD STILL BE MILD WITH HIGHS
AROUND 50 NEARLY ALL AREAS...UNLESS LOW CLOUDS MOVE IN QUICKLY
ENOUGH TO HOLD THINGS DOWN A BIT. SOUTH-SOUTHEAST WINDS WILL ALSO
REMAIN FAIRLY STRONG ON SATURDAY...AND COULD POSSIBLY AGAIN FLIRT
WITH ADVISORY CRITERIA ALTHOUGH CURRENT FORECAST ONLY HAS
SUSTAINED SPEEDS TOPPING OUT 20-25 MPH. FOR SATURDAY NIGHT...THE
BIGGEST CHANGES FROM PREVIOUS FORECAST WERE TO INTRODUCE A SLIGHT
CHANCE OF THUNDERSTORMS ALONG WITH FAIRLY WIDESPREAD RAIN
SHOWERS...AND ALSO TO CONFINE ANY SNOW POTENTIAL TO ONLY THE FAR
WESTERN SOUTH CENTRAL NEBRASKA COUNTIES WELL AFTER MIDNIGHT.
CERTAINLY FOR THE VAST MAJORITY OF THE CWA...PRECIP TYPE IS NOW
EXPECTED TO REMAIN RAIN THROUGH THE NIGHT...WITH SOME AREAS
POSSIBLY SEEING A FEW TENTHS OF INCH AND LOCALLY HIGHER. ALTHOUGH
AT LEAST A FEW WEAK THUNDERSTORMS ARE A GOOD BET GIVEN WEAK
ELEVATED INSTABILITY AND THE STRENGTH OF THE UPPER WAVE...NOT
EXPECTING ANYTHING ALL THAT STRONG ALTHOUGH SUPPOSE IT WOULDN/T
TAKE MUCH TO GET PEA SIZE HAIL. SUNDAY DAYTIME...A STRONG COLD
FRONT SWEEPS ACROSS THE CWA AS THE LOW PASSES EAST...CHANGING ANY
RAIN TO SNOW...AND ALTHOUGH NOT EXPLICITLY REFLECTED IN THE OFFICIAL
GRIDS YET...SUSTAINED SPEED OF 30+ MPH ARE VERY MUCH POSSIBLE
GIVEN THE STRENGTH OF THE LOW LEVEL PRESSURE GRADIENT. WHILE POPS
WERE REDUCED DURING THE DAY ACROSS SOUTHERN ZONES AS THE MID LEVEL
DRY SLOT DOMINATES THIS AREA...NORTHWEST ZONES ESPECIALLY
NORTHWEST OF A BEAVER CITY-GRAND ISLAND-FULLERTON LINE ARE STILL
IN LINE TO POSSIBLY RECEIVE 2+ INCHES OF WIND-BLOWN SNOW. EVEN
ASSUMING THAT THE HEAVIEST SNOW AMOUNTS MISS OUR CWA TO THE
NORTHWEST...THE COMBINATION OF SNOW AND WIND IN OUR NORTHWEST
ZONES COULD STILL ULTIMATELY PROVE WORTHY OF A WINTER WEATHER
ADVISORY...ALTHOUGH WE ARE STILL SEVERAL DAYS AWAY FROM MAKING
FORMAL DECISIONS ON HEADLINES AND PLENTY IS SUBJECT TO CHANGE.
MEANWHILE...ROUGHLY THE SOUTHEAST HALF OF THE CWA INCLUDING KS
ZONES COULD ULTIMATELY SEE VERY LITTLE...IF ANY SNOW. ALTHOUGH
SOME LIGHT SNOW/FLURRIES COULD LINGER MAINLY IN NORTHEAST COUNTIES
SUNDAY EVENING...THE CURRENT TIMING SUGGESTS THAT THIS PRECIP
EVENT SHOULD BE OVER BY MIDNIGHT SUNDAY NIGHT. TEMP-WISE...HIGHS
ON SUNDAY ARE VERY TRICKY...AS TEMPS WILL LIKELY FALL VERY QUICKLY
BEHIND THE SHARP COLD FRONT. AT LEAST FOR NOW THOUGH...ANTICIPATE
READINGS AT SOME POINT DURING THE DAY TO REACH THE MID 30S
WEST...NEAR 40 CENTRAL AND MID 40S SOUTHEAST BEFORE THE COLDER AIR
BLASTS IN.
GETTING BEYOND THE MAIN SYSTEM OF INTEREST...THE MONDAY THROUGH
WEDNESDAY TIME FRAME IS PRECIPITATION-FREE AT THIS TIME...AND
CONFIDENCE REMAINS REASONABLY HIGH FOR THE DAY 5-7 TIME RANGE THAT
IT WILL REMAIN SO. ON MONDAY/MONDAY NIGHT...THE INITIAL CLOSED LOW
THAT BRINGS THE WEEKEND WEATHER WILL ALREADY PASS WELL OFF TO THE
NORTHEAST...WHILE A SECONDARY VORT MAX REMAINS WELL TO OUR
SOUTHWEST PRIMARILY TRACKING THROUGH THE SOUTHERN ROCKIES. FORCING
FOR PRECIP PRODUCTION FROM THIS SECONDARY WAVE SHOULD STAY
SOUTHWEST OF THE CWA. FROM TUESDAY INTO TUESDAY NIGHT...A FEW MORE
QUESTIONS ARISE AS THIS SOUTHWESTERN SHORTWAVE TROUGH HEADS EAST
ACROSS THE SOUTHERN PLAINS. THE LATEST GFS SOLUTION ACTUALLY TAGS
OUR FAR SOUTHERN CWA IN NORTH CENTRAL KS WITH SOME SNOW FROM THIS
WAVE...BUT THE ECWMF FOCUSES PRECIP NO CLOSER THAN THE KS/OK
BORDER...AND THE CURRENT FORECAST LEANS TOWARD THIS SOLUTION. BY
WEDNESDAY...MODELS ADVERTISE DRY NORTHWEST FLOW ALOFT IN THE WAKE
OF THE DEPARTING SOUTHERN STREAM WAVE. TEMP-WISE MONDAY THROUGH
WEDNESDAY...FOLLOWED ALLBLEND MODEL CONSENSUS WITH HIGHS GRADUALLY
REBOUNDING FROM THE LOW-MID 30S TO THE LOW-MID 40S...WITH FAR
NORTHERN AREAS POSSIBLY STAYING IN THE 20S ON MONDAY ESPECIALLY IF
A FEW INCHES OF SNOW DO MATERIALIZE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
936 PM MST WED FEB 6 2013
.AVIATION...06Z TAFS
VFR CONDITIONS EXPECTED THROUGH THURSDAY. LEFTOVER -SHRASN FROM
KIEN TO KICR WILL CONTINUE TO DISSIPATE THIS EVENING.
.PREV DISCUSSION... /ISSUED 435 PM MST WED FEB 6 2013/
UPDATE...12Z UNR WRF/LATEST RAP SHOWED A SMALL AREA OF CONVECTIVE
-SHRASN OVER FAR SOUTHWEST SD INTO A SMALL PORTION OF SOUTH
CENTRAL SD. THIS MATCHES LATEST KUDX RADAR TRENDS...SO WILL ADD
SOME ISOLATED -SHRASN TO THE FORECAST FOR EARLY THIS EVENING.
PREV DISCUSSION... /ISSUED 302 PM MST WED FEB 6 2013/
DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS WEAK LOW PRESSURE OVER
CENTRAL ND...WITH A SURFACE TROF STRETCHING SOUTHWARD ACROSS
CENTRAL SD. UPPER LEVEL ANALYSIS SHOWS WEAK SHORTWAVE MOVING
ACROSS THE NORTHERN HIGH PLAINS...WITH A RIDGE BUILDING OVER THE
PACIFIC NW...AND A LOW OFF THE PACIFIC COAST. SKIES ARE PARTLY
SUNNY ACROSS MUCH OF THE AREA. REGIONAL RADARS NOT SHOWING MUCH IN
THE WAY OF ECHO RETURNS...EXCEPT FOR SOME WEAK RETURNS OVER THE
HIGHER TERRAIN OF WY AND THE BLACK HILLS. WITH ONLY WEAK LIFT AND
LIMITED LOW LEVEL MOISTURE IN PLACE...NOT EXPECTING MUCH MORE
THAN A FEW SPRINKLES/FLURRIES ACROSS THE BLACK HILLS THROUGH THE
AFTERNOON. TEMPS ARE CURRENTLY IN THE 40S AND LOWER 50S AT MOST
LOCATIONS. NORTHWESTERLY WINDS REMAIN BREEZY TO WINDY ACROSS
PORTIONS OF WESTERN SD...MAINLY FROM THE 2WX TO RAP CORRIDOR.
MILD WEATHER WILL CONTINUE THROUGH FRIDAY AS AN UPPER LEVEL RIDGE
SLIDES EAST ACROSS THE ROCKIES AND NORTHERN PLAINS. UPPER LOW OFF
THE PACIFIC NW COAST WILL MOVE SOUTHEAST INTO THE SOUTHWESTERN
CONUS LATE THIS WEEK...AND THEN TRACK ACROSS THE CENTRAL ROCKIES
AND PLAINS OVER THE WEEKEND. THE TRACK OF THE SYSTEM IS STILL
UNCERTAIN AT THIS POINT...BUT SOUTHERN PORTIONS OF THE CWA WILL
SEE THE BEST CHANCES FOR SNOW AND SOME ACCUMULATION...ESPECIALLY
ACROSS FAR SOUTHWESTERN INTO SOUTH CENTRAL SD.
FOR TONIGHT...SKIES WILL CLEAR OUT IN THE EVENING AS SHORTWAVE
MOVES EAST OF THE AREA. WINDS WILL ALSO DIMINISH AFTER SUNSET.
LOWS WILL MOSTLY BE IN THE 20S...WITH SOME TEENS IN THE USUAL
COLDER SPOTS. THE RIDGE WILL BUILD ACROSS THE AREA THURSDAY INTO
FRIDAY...WITH MOSTLY CLEAR SKIES AND MILD CONDITIONS PERSISTING.
THE WARMEST CONDITIONS WILL GENERALLY BE ACROSS WESTERN AND
CENTRAL AREAS ON THURSDAY AND ACROSS EASTERN AREAS ON FRIDAY.
BRISK SOUTHWESTERLY WINDS WILL DEVELOP LATE ON THURSDAY ACROSS
NORTHEASTERN WY AND THE NORTHERN BLACK HILLS AREA...PERSISTING
THROUGH THURSDAY NIGHT. SOME WIND GUSTS TO 40 MPH LOOK LIKELY
ACROSS FAVORED AREAS OF THE NORTHERN BLACK HILLS AND NORTHERN
FOOTHILLS.
AS THE RIDGE MOVES EAST BY FRIDAY NIGHT AND UPPER LOW MOVES INTO
THE CENTRAL ROCKIES...SOUTHWEST FLOW ALOFT WILL DEVELOP OVER THE
HIGH PLAINS. SHORTWAVE ENERGY IN THE FLOW AHEAD OF THE LOW WILL
TRACK ACROSS EASTERN WY OVERNIGHT. CLOUDS WILL INCREASE ACROSS THE
AREA...BUT LOW LEVEL MOISTURE WILL BE SLOW TO RETURN. THE SYSTEM
ALSO LOOKS TO BE A BIT SLOWER AS IT MOVES ACROSS THE ROCKIES. WILL
KEEP SOME LOW POPS FOR SNOW ACROSS SOUTHWESTERN PORTIONS OF
NORTHEASTERN WY AND DRY ELSEWHERE.
EXTENDED...POTENT EJECTING SW CONUS DISTURBANCE WILL SUPPORT A
STRONG WINTER STORM SYSTEM ACROSS THE CENTRAL AND NORTHERN PLAINS AT
THE START OF THE PERIOD...BRINGING WIND AND SNOW TO PORTIONS OF THE
FA. FORECAST MODELS HAVE COME TO CLOSE CONSENSUS PER THE
TRACK/STRENGTH/AND TIMING OF THIS SYSTEM...WITH AT LEAST
SEMI-NORTHERN STREAM FLOW PHASING STILL SUGGESTED IN ALL
DETERMINISTIC GUIDANCE. BRIEF BLOCKING PER THE EXPECTED WOUND UP SFC
CYCLONE AND ASSOCIATED UPPER LEVEL CLOSED LOW WILL LEAD TO A BRIEF
COOL DOWN THE EARLY PART OF NEXT WEEK AS LONG TRAJECTORY NORTHERLY
FLOW RESULTS OVER THE REGION. HOWEVER...SPLIT FLOW WILL QUICKLY
RETURN WITH WESTERN NOAM RIDGING SPILLING OVER INTO THE WESTERN
NORTHERN PLAINS BY EARLY NEXT WEEK...SLIGHTLY SLOWER THAN WHAT
PREVIOUS MODEL SOLUTIONS WHERE INDICATING. NO MAJOR CHANGES MADE TO
THE PREVIOUS FORECAST OTHER THAN CONTINUED THE TREND OF RAISING POPS
OVER SCENTRAL SD PER THIS WEEKEND/S STORM SYSTEM...DUE TO INCREASED
CONFIDENCE PER THIS SYSTEM/S TRACK GIVEN GROWING AGREEMENT PER
DETERMINISTIC MODELS. ANALYSIS OF FGEN/WAA/MID LAPSE RATES SUGGEST A
RATHER STRONG DEFORMATION ZONE WILL FORM OVER NORTHERN NE INTO
SD...WITH A PERIOD OF HEAVY SNOW LIKELY ESP GIVEN THE DEVELOPING
GOMEX CONNECTION INDICATED IN H85 THETA-E PROGS. THE EXACT TRACK OF
THE HEAVIEST SNOW IS STILL IN QUESTION...BUT CURRENT CONSENSUS
INDICATIONS SUGGEST INVOF TODD/MELLETTE/AND TRIPP COUNTIES AND
EAST...WHERE THE POTENTIAL FOR 4 TO 6 INCHES EXISTS. IN
ADDITION...VERY STRONG N/NW WINDS WOULD LIKELY CREATE AREAS OF
BLOWING AND DRIFTING SNOW...WITH SIG VIS REDUCTION. WILL FRESHEN THE
HWO FOR THIS CONCERN. THE REMAINDER OF THE FA WILL SEE MUCH LOWER
CHANCES FOR PRECIP WITH ACCUMS GENERALLY 2 INCHES TO A
DUSTING...SAVE THE NORTHERN BH WHERE HIGHER AMOUNTS ARE QUITE
POSSIBLE GIVEN A PERIOD OF UPSLOPE SUN/SUN NIGHT. COLD AIR WILL
SETTLE OVER THE REGION ON THE BACKSIDE OF THIS SYSTEM WITH BELOW
NORMAL TEMPS FORECAST MON. UPPER LEVEL RIDGING WILL DEVELOP BY
TUE...SUPPORTING WARMING TEMPS THROUGH WED...WITH NORMAL TO ABOVE
NORMAL TEMPS BY THEN...ESP IN AREAS THAN DON/T SEE MUCH SNOW THIS
WEEKEND.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...WFO UNR
LONG TERM...WFO UNR
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CST WED FEB 6 2013
.SHORT TERM...TONIGHT
553 PM CST WED FEB 6 2013
DRYING AND SUBSIDENCE HAS COME IN BEHIND THE BAND OF SNOW THAT
IMPACTED TAYLOR/CLARK COUNTIES THE PAST FEW HOURS. THIS DRYING AND
SUBSIDENCE HAS EFFECTIVELY ENDED MUCH OF THE PRECIPITATION ACROSS
SOUTHEAST MINNESOTA AND IN REALITY MOST LOCATIONS NORTH OF
INTERSTATE 90. MEANWHILE...AN AREA OF WARM ADVECTION PRECIPITATION
CONTINUES ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
06.12Z HIRES ARW AND 06.20Z RAP/HRRR RUNS HAVE ALL HAD A DECENT
HANDLE ON THE ONGOING PRECIPITATION TRENDS...KEEPING THE BULK OF
THE PRECIPITATION THIS EVENING ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN AND PERHAPS JUNEAU/ADAMS COUNTIES. MUCH OF
SOUTHEAST MINNESOTA INTO BUFFALO...TREMPEALEAU AND LA CROSSE
COUNTIES STAY DRY. AS A RESULT...CONFIDENCE IS JUST NOT HIGH
ENOUGH TO MAINTAIN THE ADVISORY FOR MUCH OF THIS AREA FOR THE
EVENING HOURS. FILLMORE...HOUSTON AND LA CROSSE COUNTIES COULD BE
ON THE VERY EDGE OF HAVING SOME PRECIPITATION DRIFT IN AND
OUT...THOUGH. IN JACKSON/MONROE/JUNEAU/ADAMS/TAYLOR/CLARK...THE
RECENT SNOW HAS HELD TEMPERATURES DOWN...AND WITH HIGHER MOISTURE
APPROACHING FROM THE SOUTH...CONCERNED FREEZING DRIZZLE COULD
DEVELOP AS SUGGESTED BY RAP SOUNDINGS. THUS...HAVE MAINTAINED THE
ADVISORY FOR THIS AREA DURING THE EVENING. AFTER MIDNIGHT AND
EVEN INTO THURSDAY MORNING...CONFIDENCE INCREASES OF BOTH FREEZING
DRIZZLE AND FOG DEVELOPING OVER THE NORTHWEST HALF OF THE FORECAST
AREA...ESPECIALLY TOWARDS LATE IN THE NIGHT...WITH THE POTENTIAL
SUGGESTED OF THE MID CLOUDS CLEARING OUT. WILL REALLY HAVE TO
WATCH VISIBILITIES WITH THE FOG...WHICH IS DISCUSSED MORE IN THE
AVIATION SECTION BELOW.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
223 PM CST WED FEB 6 2013
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SYSTEM THAT MOVES
THROUGH THE REGION SATURDAY NIGHT THROUGH SUNDAY NIGHT. THE 06.12Z
GFS/ECMWF HAVE COME INTO FAIRLY GOOD AGREEMENT WITH A CONTINUED
NORTHWARD SHIFT WITH THE TRACK OF THE LOW. THIS SYSTEM IS CURRENTLY
LOCATED OFF OF THE COAST OF THE PACIFIC NORTHWEST AND WILL STALL OUT
ACROSS THE CENTRAL US ROCKIES EARLY THIS WEEKEND. THE EASTERN
PORTION OF THE TROUGH EJECTS OUT TO THE NORTHEAST INTO THE NORTHERN
PLAINS SATURDAY NIGHT INTO EARLY SUNDAY. THE 06.12Z GFS/ECMWF ARE
AGAIN VERY CONSISTENT WITH THIS RUN FOR TAKING THE CORE OF THE LOW
FROM EASTERN COLORADO SATURDAY NIGHT THROUGH CENTRAL MINNESOTA BY
SUNDAY NIGHT AND THEN INTO THE UPPER GREAT LAKES MONDAY. AT THE
SURFACE...THE LOW IS EXPECTED TO TRACK FROM NORTH CENTRAL IOWA
SUNDAY INTO NORTHERN WISCONSIN BY SUNDAY NIGHT. THIS LEADS TO THE
REGION BEING IN THE WARM SECTOR FOR MOST OF THIS SYSTEM WITH RAIN
BEING THE MAIN PRECIPITATION TYPE. THE BIGGEST CONCERN WILL BE AS
THE PRECIPITATION MOVES IN FROM THE SOUTH SATURDAY NIGHT MIXED
PRECIPITATION TYPES POSSIBLE. DETAILS WILL EMERGE OVER THE NEXT FEW
DAYS...BUT 06.12Z GFS BUFKIT SOUNDINGS SHOW A WARM LAYER OVER A SUB
FREEZING NEAR SURFACE LAYER THAT WOULD LEAD TO A MIX OF SLEET AND
FREEZING RAIN AT THE ONSET. THE LOW LEVEL PROFILE THEN WARMS ENOUGH
THAT MUCH OF SUNDAY SHOULD JUST BE RAIN BEFORE COLDER AIR MOVES IN
ON THE BACK SIDE SUNDAY NIGHT INTO MONDAY.
NOT MUCH IN THE WAY OF COLD AIR ADVECTION ON THE BACK SIDE OF THIS
AMPLIFIED SYSTEM...SO THERE SHOULD NOT BE MUCH OF A COOL DOWN AFTER
THE SYSTEM PASSES. HIGH PRESSURE BUILDS IN AND CONDITIONS SHOULD
REMAIN DRY THROUGH MID WEEK.
&&
.AVIATION...THROUGH 06Z FRIDAY
1148 PM CST WED FEB 6 2013
LOW LEVEL DRY AIR BETWEEN JUST ABOVE THE SURFACE AND 4000 FT AGL
HAS KEPT CONDITIONS VFR THUS FAR. THIS SHOULD CONTINUE FOR THE
NEXT 4 HOURS OR SO...WHICH IS WHEN A COLD FRONT CURRENTLY PASSING
THROUGH MINNEAPOLIS IS EXPECTED TO REACH THE TAF SITES. ONE
CONCERN WHICH WILL HAVE TO BE WATCHED IS THE CURRENT ALTOSTRATUS
CLEARING OUT NORTH OF KRST. FAIRBAULT AT 1134 PM DROPPED TO 1/2SM
QUICKLY. ANTICIPATING RIGHT NOW THAT THE ALTOSTRATUS WILL STAY IN
PLACE...PREVENTING FOG FORMATION. IN THE WAKE OF THE COLD
FRONT...CEILINGS QUICKLY DROP TO MVFR AND A LITTLE FARTHER NORTH
DROP TO IFR. VISIBILITIES ALSO DROP TO MVFR. ANTICIPATING THE
COMBINATION OF ADDITIONAL DIURNAL COOLING AND THE COLD AIR RUNNING
INTO A MORE MOIST AIRMASS OVER THE AREA TO RESULT IN LOWER
CEILINGS AND VISIBILITIES WHEN THE FRONT PASSES THROUGH THE TAF
SITES. THUS...HAVE BOTH SITES DROPPING TO AT LEAST IFR IN
VISIBILITY AND CEILING BY 14Z. IN ADDITION...WEAK LOW LEVEL LIFT
MAY PROMOTE -FZDZ DEVELOPMENT BEHIND THE FRONT THROUGHOUT MUCH OF
THE DAY. THIS LIFT EXITS LATE IN THE DAY...BUT COLD ADVECTION
PERSISTS...WHICH SHOULD ALLOW CEILINGS AND VISIBILITIES TO RISE
THROUGH THE EVENING. HAVE KEPT MVFR CEILINGS IN UNTIL
06Z...THOUGH...WITH MOISTURE TRAPPED ON THE COLD FRONTAL
INVERSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1137 PM CST WED FEB 6 2013
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ017-029-
034-042>044-053>055-061.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ032-033-
041.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1041 PM CST WED FEB 6 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...HAVE ALREADY UPDATED THE GRIDS/ZFP/SPS/WSW/HWO.
MAIN BAND OF SNOW THAT BROUGHT 1-3 INCHES OF SNOW TO THE FORECAST
AREA WAS TAPERING OFF OVER FAR NE WI. SYNOPTIC SCALE FORCING IS
EXPECTED TO WEAKEN OVERNIGHT...AND MID-LEVEL DRY AIR IS FCST TO
MOVE INTO THE RGN. ALTHOUGH SCT/OCNL LIGHT SNOW MAY CONTINUE
OVERNIGHT...ESPECIALLY IN OUR SOUTHERN COUNTIES...THE MAIN PCPN
TYPE IS EXPECTED TO TRANSITION TO FREEZING DRIZZLE. THIS THREAT
WILL JUSTIFY KEEPING THE ADVISORY GOING THROUGH THE NIGHTTIME HOURS.
ON THURSDAY...STRONG UPPER DIVG DUE TO THE RRQ OF AN UPPER JET AND
SHARP UPPER TROF WILL CAUSE SIGNIFICANT SNOW TO REDEVELOP ACROSS
THE SE HALF OF THE FORECAST AREA. ADDITIONAL ACCUMS OF 3 TO 5
INCHES ARE EXPECTED ACROSS THE FOX VALLEY/LKSHR AREAS FROM LATE
THURSDAY MORNING THROUGH THURSDAY EVG...WITH 1 TO 3 INCHES ACROSS
THE NW PORTION OF THE ADVISORY AREA.
HAVE ADJUSTED THE SEGMENTS OF THE WSW TO ACCOUNT FOR THE DIFFERENCES
IN EXPECTED SNOWFALL ACCUMS ON THURSDAY.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 540 PM CST WED FEB 6 2013...
SHORT TERM...TONIGHT AND THURSDAY.
WINTER WEATHER ADVISORY FOR SNOW AND FREEZING DRIZZLE IS THE MAIN
CONCERN DURING THIS PART OF THE FORECAST. MODELS SHOWED
SIGNIFICANT UPPER LEVEL DIVERGENCE ACROSS MUCH OF THE FORECAST
AREA LATE THIS AFTERNOON AND TONIGHT. THIS WAS ASSOCIATED WITH
THE RIGHT ENTRANCE REGION OF A 120+ KNOT 300MB JET MAX. STRONG
UPPER DIVERGENCE ASSOCIATED WITH A WEAKER JET MAX RETURNS TO THE
AREA ON THURSDAY. THE COMBINATION OF LIFT FROM WARM ADVECTION AND
UPPER DIVERGENCE WAS PRODUCING A BAND OF SNOW THAT EXTENDED FROM
THE MINNESOTA ARROWHEAD SOUTHEAST TO SOUTHERN WISCONSIN. SNOWFALL
IN THIS BAND WAS RATHER HEAVY SO IT SHOULD PRODUCE A QUICK
ACCUMULATION OF AN INCH OR TWO AS IT PASSES. RADAR SHOWED A BAND
OF ECHOES ACROSS NORTHERN IOWA BUT SURFACE OBSERVATIONS WERE NOT
INDICATING PRECIPITATION WITH THIS FEATURE. THE 18Z RUC SHOWED QPF
IN THIS AREA SPREADING NORTHEAST INTO CENTRAL AND EASTERN
WISCONSIN OVERNIGHT. MODELS HINTED AT SOME MID LEVEL DRYING
AFTER MIDNIGHT SO HAVE FREEZING DRIZZLE MENTIONED ALONG WITH THE
SNOW.
AN INVERTED SURFACE TROUGH AXIS IS EXPECTED TO PASS THROUGH THE
AREA ON THURSDAY. A 500MB SHORT WAVE APPROACHING THE STATE WILL
COMBINE WITH THE UPPER DIVERGENCE AND SURFACE BOUNDARY TO PRODUCE
MORE SIGNIFICANT SNOWFALL...MAINLY ACROSS EAST CENTRAL WISCONSIN.
TIME/HEIGHT SECTIONS FROM THE 12Z NAM/12Z GFS/09Z SREF DID NOT
INDICATE FREEZING PRECIPITATION FOR ANY OF THE LOCATIONS IN THE
AREA DURING THE SHORT TERM...THOUGH THEY DID IN THE MSN AND MKE
AREAS. HPC WINTER PRECIPITATION GUIDANCE KEPT ANY MEASURABLE
FREEZING PRECIPITATION SOUTH OF THE AREA WITH 24 HOUR TOTALS
THROUGH 00Z FRIDAY OF 6+ INCHES FROM JUST EAST OF GREEN BAY AND
THE FOX CITIES TO LAKE MICHIGAN.
LONG TERM...THU NGT THRU NEXT WED. A NEARLY ZONAL FLOW ACROSS THE
CONUS AT THE ONSET TO TRANSITION TO AN AMPLIFIED FLOW THIS WEEKEND
AS A LARGE UPR RDG BUILDS OFF THE WEST COAST AND A DOWNSTREAM
LONGWAVE TROF SETS UP OVER THE ROCKIES INTO THE CNTRL CONUS. MDLS
CONT TO SHOW A MAJOR SYSTEM WL LIFT NE FROM CO INTO THE GREAT
LAKES SAT NGT INTO MON BRINGING SNOW AND MIXED PCPN TO NE WI. MEAN
FLOW EVENTUALLY BECOMES SPLIT OVER THE ERN PACIFIC WITH THE UPR
TROF SHIFTING EAST. HOWEVER...A SFC HI SHOULD KEEP THE WEATHER
RELATIVELY QUIET WITH TEMPS OVERALL SLIGHTLY ABOVE NORMAL.
LIGHT SNOW TO LINGER INTOI THU EVENING AS THE SHORTWAVE TROF MOVES
THRU WI. CONCERNED ABOUT ERN WI WHERE LIFT IS STRONGER AND WINDS
JUST ABOVE THE SFC ARE FCST TO BE N-NE. MAY NEED TO RAISE POPS A
BIT...ESPECIALLY IN THE EAST WHERE LAKE ENHANCEMENT TO TAKE PLACE
AND THIS COULD ADD UP TO AN INCH OF ADDITIONAL ACCUMULATION. PCPN
WL TAPER OFF FROM WEST TO EAST DURING THE OVRNGT HOURS...ALTHO THE
LAKESHORE MAY NOT SEE THE SNOW COME TO A COMPLETE END TIL CLOSE TO
DAYBREAK. HI PRES BUILDING INTO THE WRN GREAT LAKES LATER THU NGT
COULD BEGIN TO BREAK UP THE CLOUDS ACROSS CNTRL WI AND MAY NEED TO
LWER TEMPS A BIT TO COMPENSATE. THIS AREA OF HI PRES WL BE SITUATED
OVER WI ON FRI PROVIDING FOR PLENTY OF SUNSHINE...LIGHT WINDS AND
TYPICAL TEMPS FOR EARLY FEBRUARY. LOOK FOR READINGS TO GENERALLY
REACH THE 25-30 DEG RANGE OVER ALL OF NE WI.
THE HI PRES BEGINS TO SLIDE TO OUR EAST FRI NGT ALLOWING A RETURN
FLOW TO DEVELOP OVER WI. THE ONSET OF WEAK ISEN LIFT SHOULD BRING
SOME HI CLOUDS INTO THE FCST AREA...HOWEVER STILL EXPECT TEMPS TO
DROP OFF DUE TO FRESH SNOW AND LIGHT WINDS. PREFER THE COLDER SIDE
OF GUIDANCE AND HAVE SIGNIFICANTLY CHOPPED TEMPS INTO THE SINGLE
DIGITS/LOWER TEENS. AS THE LONGWAVE TROF CHUGS ACROSS THE ROCKIES
ON SAT...LEE-SIDE CYCLOGENESIS TO TAKE PLACE OVER SE CO AS A SFC
LOW QUICKLY INTENSIFIES. MEANWHILE...THE SFC HI CONTS TO PULL
FARTHER EAST AND THE SOUTH WINDS STEADILY INCREASE AS THE PRES
GRADIENT TIGHTENS. THESE SOUTH WINDS WL ALSO HELP BRING GULF
MOISTURE NWD...SO WE SHOULD SEE CLOUDS ON THE INCREASE DURING THE
DAY. MAX TEMPS ARE EXPECTED TO REACH NEAR THE 30 DEG MARK DESPITE
THE CLOUDS.
AS A 110+ KT UPR JET ROUNDS THE BASE OF THE UPR TROF...THE SFC LOW
IS FCST TO START MOVING NE INTO THE CNTRL PLAINS SAT NGT AND REACH
THE MIDWEST (VICINITY NW IA) ON SUNDAY. LOW-LEVEL MOISTURE CONTS
TO STREAM INTO WI WITH A WRMFNT LIFTING TO THE WI/IL BORDER BY
SUNDAY AFTERNOON. MID-LEVEL FORCING (BOTH Q-G AND FRONTOGENETICAL)
INCREASE DURING THIS PERIOD OVER THE REGION WITH THE LEFT EXIT
REGION OF THE UPR JET ADDING LIFT. EXPECT TO SEE PCPN GRADUALLY
OVERSPREAD WI ON SUNDAY...BUT WHAT TYPE OF PCPN? WHILE MOST OF THE
MDLS ARE GETTING CLOSER TO A FINAL TRACK SOLUTION (EXCEPT THE GEM
WHICH REMAINS SOUTH)...THE THERMAL FIELDS VARY BETWEEN THE WARMER
GFS AND THE COOLER ECWMF/UKMET. DIFFICULT TO DETERMINE WHAT THE
SFC TEMPS TO BE AT ONCE THE PCPN BEGINS...AS THIS WOULD PLAY A
LARGE ROLE IN DETERMINING RAIN VS. FREEZING RAIN VS. SNOW. IN
ESSENCE...IT IS JUST TOO EARLY TO TRY AND PINPOINT PCPN TYPES AT
THIS TIME...OTHER THAN N-CNTRL WOULD HAVE THE BEST CHC OF SEEING
ALL SNOW AND E-CNTRL WI WOULD HAVE THE BEST CHC OF SEEING MORE
RAIN THAN SNOW WITH A MIX IN BETWEEN.
SNOW/MIXED PCPN WL CONT SUNDAY NGT AS THE SFC LOW TRACKS NE INTO
N-CNTRL WI WITH THE BETTER SNOW ACCUMULATION OCCURRING OVER THE NW
1/4 OF WI. THIS WOULD LIKELY CLIP PARTS OF N-CNTRL WI...BUT FOR
MOST OF THE FCST AREA...TOO MUCH OF A MIX WL LIMIT SNOW AMOUNTS.
AS THE SFC LOW PULLS AWAY ON MON AND COLDER AIR GETS PULLED SWD...
ANY LINGERING MOISTURE WOULD TRANSITION BACK TO ALL SNOW. SINCE
DEEPER MOISTURE TO ALREADY HAVE EXITED...DO NOT EXPECT TO SEE MUCH
ADDITIONAL ACCUMULATION ON MON...ESPECIALLY IF SOME FREEZING
DRIZZLE MIXES IN. OTHER THAN SOME LIGHT LAKE EFFECT SNOW SHWRS
OVER VILAS CNTY MON NGT...THE WEATHER BECOMES FAIRLY TRANQUIL WITH
PERHAPS SOME FLURRIES ON TUE AS THE POSITIVE-TILTED UPR TROF MOVES
THRU THE GREAT LAKES. HI PRES PASSING TO OUR SOUTH ON WED WL BRING
A DRY DAY WITH TEMPS WARMING UP A BIT.
&&
.AVIATION...THERE WILL BE A LULL IN THE SNOW ACCUMULATION
OVERNIGHT THROUGH LATE THURSDAY MORNING...BUT OCNL FREEZING
DRIZZLE AND LIGHT SNOW WILL CONTINUE DURING THIS PERIOD. THE SNOW
SHOULD PICK UP AGAIN BY MIDDAY THURS...AND BE HEAVIEST OVER THE
FOX VALLEY/LKSHR AREAS DURING THE AFTERNOON. IFR CONDITIONS
WILL PREVAIL LATE TONIGHT INTO THURSDAY MORNING...AND CONTINUE
OVER THE FOX VALLEY AND LAKESHORE AREAS WITH THE HEAVIER SNOW
DURING THE AFTERNOON.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THURSDAY FOR WIZ013-
020>022-030-031-035>040-045-048>050-073-074.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
539 AM CST THU FEB 7 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN IS WITH ONGOING RAIN AND SMALL POTENTIAL FOR
FZRA/IP/SN THIS MORNING. EXPECTING THE RAIN TO PERSIST THROUGH MUCH
OF THE MORNING BEFORE SHIFTING EAST BY AROUND 18Z OR EARLIER. LEANED
TOWARD THE NAM12 AS IT HAS THE BEST HANDLE ON CURRENT RADAR TRENDS.
THE HIRES WRF MODEL RUNS AND HRRR HAVE MUCH OF THE PRECIP CONFINED
TO THE SOUTHEAST BY 18Z AS WELL.
THE COLD FRONT...CURRENTLY LOCATED ACROSS NORTHERN IOWA JUST SOUTH
OF A MASON CITY TO SAC CITY LINE WILL CONTINUE TO SHIFT SOUTH
THROUGH THE MORNING HOURS. CAA INCREASES BY MID TO LATE MORNING AND
FRONT SHOULD CLEAR THE FORECAST AREA BY AROUND 18Z EXCEPT FOR THE
FAR SOUTHEAST. FORECAST SOUNDINGS AT MCW/ALO INDICATING SOME ICE
INTRODUCTION AT THE TOP OF THE SNOW GROWTH ZONE...BUT A DEEP DRY
LAYER B/T 600-900MB ENTRAIN INTO THIS AREA WITH THE CAA. STILL HAVE
SOME SATURATION NEAR THE SURFACE AND MIGHT BE DEEP ENOUGH FOR FZDZ.
HAVE INCLUDED MENTION OF FZDZ THROUGH THE MORNING. OTHERWISE ANY
PRECIP FALLING ALOFT LOOKS TO HAVE A TOUGH TIME REACHING THE GROUND
WITH THAT LARGE DRY LAYER. SEEMS TO BE MATCHING WELL WITH CURRENT
TRENDS AS NOT SEEING ANY PRECIP NEAR MCW/ALO ATTM. SO HAVE LOW
CONFIDENCE WITH ANY MIXED PRECIP THIS MORNING...SO LOWERED POPS THIS
MORNING AND WENT DRY BY THIS AFTERNOON OVER THE NORTHEAST. FURTHER
SOUTH...EXPECTING PRECIP TO REMAIN ALL RAIN AS TIMING OF COLD AIR IS
DELAYED UNTIL AFTER RAIN HAS DISSIPATED. NO MAJOR CHANGES TO
TEMPERATURE TREND WITH THE COLD FRONT MOVING THROUGH...SO KEPT
MENTION OF THE NON-DIURNAL TREND.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
WEEKEND SYSTEM WILL BE THE ONLY SIGNIFICANT CONCERN THIS PERIOD.
SENSIBLE WEATHER WITH CURRENT SYSTEM SHOULD HAVE DEPARTED IA BY 00Z
LEADING TO FAIR WEATHER AND EVENTUALLY MODERATING TEMPERATURES TO
END THE WEEK AS HIGH PRESSURE CROSSES THE UPPER MS VALLEY INTO THE
GREAT LAKES. THE WEATHER CHANGES QUICKLY BY SAT NIGHT HOWEVER AND
MODELS CONTINUE TO SHOW GOOD AGREEMENT WITH EVOLUTION OF THIS SYSTEM
LEADING TO RELATIVELY HIGH CONFIDENCE. ECMWF/GFS BOTH DEPICT SHARP
INCREASE IN FORCING 3KM AND BELOW INCLUDING IMPRESSIVE WARM AIR AND
THETA-E ADVECTION. THIS SURGE WILL ALSO LEAD TO LOWER STATIC
STABILITIES AS SUGGESTED BY TOKEN ELEVATED CAPES AND INCREASING K
INDICES. THIS HAS LEAD TO A MENTION OF ISOLATED THUNDER SOUTH LATE
SAT NIGHT AND EARLY SUN...SIMILAR TO WHAT IS PRESENTLY OCCURRING
SOUTH THIS MORNING. MUCH LIKE WHAT WAS SHOWN YESTERDAY...1-3KM
SURGE OF FORCING IS CLOSELY FOLLOWED BY DIVERGENCE AHEAD OF UPPER
LEVEL LOW AND DIFFERENTIAL PVA ON THE NOSE OF THE DRY SLOT. THIS
HAS LEAD TO CATEGORICAL POPS OVERNIGHT INTO SUN MORNING WHICH IS
ALSO SUPPORTED BY GEFS AND SREF PRECIP PROBS. SIGNIFICANT PRECIP
SHOULD THEN END BY SUN NIGHT WITH LINGERING WRAP AROUND MOISTURE BUT
LITTLE IN THE WAY OF FORCING.
EVEN THOUGH THERE IS RELATIVELY HIGHER CONFIDENCE IN SYSTEM TRACK
AND PRECIPITATION EVOLUTION...WARM LAYER TEMPS WILL STILL BE
HOVERING AROUND CRITICAL 1-3C VALUES NORTH KEEPING PRECIP TYPE IN
QUESTION THERE. EVOLUTION OF RAW MODEL SURFACE TEMPS...AND
DEPICTION OF ECMWF/GFS/GEM WARM LAYERS ALOFT...SUGGEST A WINTRY
MIXED BAG OF PRECIP NE QUARTER-THIRD SAT NIGHT INTO EARLY SUN
SWITCHING TO RAIN FORECAST AREA WIDE BY LATE MORNING. EXPECT SOME
SORT OF TRAVEL PROBLEMS EARLY SUN WHICH WILL BE HIGHLIGHTED IN THE
HWO...BUT DETAILS DIFFICULT AT THIS POINT. FOR INSTANCE MCW
SOUNDINGS AT 12Z SUN...NEAR THE PEAK UVM...RANGE FROM GEM/SREF ALL
SNOW...TO ECMWF RAIN/SNOW MIX...TO NAM/GFS AT OR NEARLY ALL LIQUID
WITH A 3-4C WARM LAYER AND ALL WITH SURFACE TEMPS PLUS/MINUS 32F.
SYSTEM MAY JUST LINGER INTO MON NORTH BUT ESSENTIALLY BE DONE BY
THAT TIME. MAIN STORY FOR MON WILL LIKELY BE GUSTY WNW WINDS.
OTHER MODELS LESS BULLISH...BUT GFS SHOWS MCW GUSTS OVER 40 MPH.
THIS THEN LEADS TO FAIR WEATHER FOR THE HEART OF THE NEXT WORK WEEK
WITH LITTLE IN THE WAY OF FORCING OR MOISTURE WITH MIDWEST IN
INACTIVE NW FLOW BEHIND DEPARTING LONG WAVE TROUGH AND AHEAD OF WRN
CONUS OR ROCKIES RIDGE.
&&
.AVIATION...07/12Z
LIFR/IFR STRATUS DECK WILL CONTINUE TO MOVE SOUTH ACROSS THE
FORECAST AREA THIS MORNING BEHIND THE COLD FRONT. EXPECTING MCW/FOD
TO DROP TO IFR/LIFR VIS/CIGS BY AROUND 13Z THIS MORNING. THE HIRES
MODELS AND MOS GUIDANCE KEEP STRATUS THROUGH TONIGHT ACROSS THE
STATE AND SEE NO REASON FOR IT TO DISSIPATE AS LOW MOISTURE REMAINS
STEADY WITH THE CAA THROUGH TODAY AND THEN BECOMES TRAPPED UNDER
INVERSION WITH SURFACE HIGH BUILDS IN TONIGHT. HAVE IFR/LIFR
CONDITIONS THROUGH END OF THE FORECAST PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
409 AM CST THU FEB 7 2013
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN IS WITH ONGOING RAIN AND SMALL POTENTIAL FOR
FZRA/IP/SN THIS MORNING. EXPECTING THE RAIN TO PERSIST THROUGH MUCH
OF THE MORNING BEFORE SHIFTING EAST BY AROUND 18Z OR EARLIER. LEANED
TOWARD THE NAM12 AS IT HAS THE BEST HANDLE ON CURRENT RADAR TRENDS.
THE HIRES WRF MODEL RUNS AND HRRR HAVE MUCH OF THE PRECIP CONFINED
TO THE SOUTHEAST BY 18Z AS WELL.
THE COLD FRONT...CURRENTLY LOCATED ACROSS NORTHERN IOWA JUST SOUTH
OF A MASON CITY TO SAC CITY LINE WILL CONTINUE TO SHIFT SOUTH
THROUGH THE MORNING HOURS. CAA INCREASES BY MID TO LATE MORNING AND
FRONT SHOULD CLEAR THE FORECAST AREA BY AROUND 18Z EXCEPT FOR THE
FAR SOUTHEAST. FORECAST SOUNDINGS AT MCW/ALO INDICATING SOME ICE
INTRODUCTION AT THE TOP OF THE SNOW GROWTH ZONE...BUT A DEEP DRY
LAYER B/T 600-900MB ENTRAIN INTO THIS AREA WITH THE CAA. STILL HAVE
SOME SATURATION NEAR THE SURFACE AND MIGHT BE DEEP ENOUGH FOR FZDZ.
HAVE INCLUDED MENTION OF FZDZ THROUGH THE MORNING. OTHERWISE ANY
PRECIP FALLING ALOFT LOOKS TO HAVE A TOUGH TIME REACHING THE GROUND
WITH THAT LARGE DRY LAYER. SEEMS TO BE MATCHING WELL WITH CURRENT
TRENDS AS NOT SEEING ANY PRECIP NEAR MCW/ALO ATTM. SO HAVE LOW
CONFIDENCE WITH ANY MIXED PRECIP THIS MORNING...SO LOWERED POPS THIS
MORNING AND WENT DRY BY THIS AFTERNOON OVER THE NORTHEAST. FURTHER
SOUTH...EXPECTING PRECIP TO REMAIN ALL RAIN AS TIMING OF COLD AIR IS
DELAYED UNTIL AFTER RAIN HAS DISSIPATED. NO MAJOR CHANGES TO
TEMPERATURE TREND WITH THE COLD FRONT MOVING THROUGH...SO KEPT
MENTION OF THE NON-DIURNAL TREND.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
WEEKEND SYSTEM WILL BE THE ONLY SIGNIFICANT CONCERN THIS PERIOD.
SENSIBLE WEATHER WITH CURRENT SYSTEM SHOULD HAVE DEPARTED IA BY 00Z
LEADING TO FAIR WEATHER AND EVENTUALLY MODERATING TEMPERATURES TO
END THE WEEK AS HIGH PRESSURE CROSSES THE UPPER MS VALLEY INTO THE
GREAT LAKES. THE WEATHER CHANGES QUICKLY BY SAT NIGHT HOWEVER AND
MODELS CONTINUE TO SHOW GOOD AGREEMENT WITH EVOLUTION OF THIS SYSTEM
LEADING TO RELATIVELY HIGH CONFIDENCE. ECMWF/GFS BOTH DEPICT SHARP
INCREASE IN FORCING 3KM AND BELOW INCLUDING IMPRESSIVE WARM AIR AND
THETA-E ADVECTION. THIS SURGE WILL ALSO LEAD TO LOWER STATIC
STABILITIES AS SUGGESTED BY TOKEN ELEVATED CAPES AND INCREASING K
INDICES. THIS HAS LEAD TO A MENTION OF ISOLATED THUNDER SOUTH LATE
SAT NIGHT AND EARLY SUN...SIMILAR TO WHAT IS PRESENTLY OCCURRING
SOUTH THIS MORNING. MUCH LIKE WHAT WAS SHOWN YESTERDAY...1-3KM
SURGE OF FORCING IS CLOSELY FOLLOWED BY DIVERGENCE AHEAD OF UPPER
LEVEL LOW AND DIFFERENTIAL PVA ON THE NOSE OF THE DRY SLOT. THIS
HAS LEAD TO CATEGORICAL POPS OVERNIGHT INTO SUN MORNING WHICH IS
ALSO SUPPORTED BY GEFS AND SREF PRECIP PROBS. SIGNIFICANT PRECIP
SHOULD THEN END BY SUN NIGHT WITH LINGERING WRAP AROUND MOISTURE BUT
LITTLE IN THE WAY OF FORCING.
EVEN THOUGH THERE IS RELATIVELY HIGHER CONFIDENCE IN SYSTEM TRACK
AND PRECIPITATION EVOLUTION...WARM LAYER TEMPS WILL STILL BE
HOVERING AROUND CRITICAL 1-3C VALUES NORTH KEEPING PRECIP TYPE IN
QUESTION THERE. EVOLUTION OF RAW MODEL SURFACE TEMPS...AND
DEPICTION OF ECMWF/GFS/GEM WARM LAYERS ALOFT...SUGGEST A WINTRY
MIXED BAG OF PRECIP NE QUARTER-THIRD SAT NIGHT INTO EARLY SUN
SWITCHING TO RAIN FORECAST AREA WIDE BY LATE MORNING. EXPECT SOME
SORT OF TRAVEL PROBLEMS EARLY SUN WHICH WILL BE HIGHLIGHTED IN THE
HWO...BUT DETAILS DIFFICULT AT THIS POINT. FOR INSTANCE MCW
SOUNDINGS AT 12Z SUN...NEAR THE PEAK UVM...RANGE FROM GEM/SREF ALL
SNOW...TO ECMWF RAIN/SNOW MIX...TO NAM/GFS AT OR NEARLY ALL LIQUID
WITH A 3-4C WARM LAYER AND ALL WITH SURFACE TEMPS PLUS/MINUS 32F.
SYSTEM MAY JUST LINGER INTO MON NORTH BUT ESSENTIALLY BE DONE BY
THAT TIME. MAIN STORY FOR MON WILL LIKELY BE GUSTY WNW WINDS.
OTHER MODELS LESS BULLISH...BUT GFS SHOWS MCW GUSTS OVER 40 MPH.
THIS THEN LEADS TO FAIR WEATHER FOR THE HEART OF THE NEXT WORK WEEK
WITH LITTLE IN THE WAY OF FORCING OR MOISTURE WITH MIDWEST IN
INACTIVE NW FLOW BEHIND DEPARTING LONG WAVE TROUGH AND AHEAD OF WRN
CONUS OR ROCKIES RIDGE.
&&
.AVIATION...07/06Z
PRECIPITATION BECOMING MORE WIDESPREAD ACROSS THE SOUTHERN HALF OF
THE AREA...AND SHOULD REMAIN AT KDSM AND KOTM MUCH OF THE
NIGHT...AND PUSH INTO KALO LATER TONIGHT. KMCW AND KFOD NOW EXPECTED
TO BE DRY. SFC TEMPS EXPECTED TO REMAIN NEAR FREEZING OR ABOVE AT
TAF SITES WITH PRECIP EXPECTED...SO HAVE KEPT PRECIP ALL -RA. VFR
CIGS EXPECTED TO LOWER THROUGH THE NIGHT TO MVFR...AND THEN IFR AS
THE COLD FRONT PUSHES THROUGH THE CWA. SOME LIGHT FOG ALSO POSSIBLE
IN THE VICINITY OF THE FRONT OR BEHIND THE FRONT. STRATUS TO REMAIN
ACROSS THE ENTIRE CWA FOR THURSDAY INTO THURSDAY EVENING. WINDS TO
SHIFT AROUND TO THE NORTHWEST AND PICK UP IN INTENSITY BEHIND THE
FRONT FOR THURSDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
525 AM CST THU FEB 7 2013
...UPDATE TO AVIATION...
.DISCUSSION...
MAIN AREA OF PRECIPITATION SO FAR HAS BEEN JUST UPSTREAM OF BEST
LOW-MID LEVEL MOISTURE CONVERGENCE WHERE STRONGER LOW LEVEL JET IS
BEING MAINTAINED EAST OF 850MB LOW. UPPER WAVE CONTINUES ITS
EASTWARD PROGRESS BUT HAS STILL JUST ENTERED THE PLAINS AT 08Z.
LATEST RAP AND 06Z NAM TAKE THIS AREA OF CONVERGENCE EAST THROUGH
THE POST-SUNRISE HOURS WHILE THE UPPER WAVE...CONTINUING TO SLOW
ITS PACE...HELPS SPREAD PRECIP NORTHEAST. THIS WILL KEEP PRECIP IN
PLACE SLIGHTLY LONGER...BUT A QUICK CLEARING IS ON TRACK FOR THE
AFTERNOON AS THE UPPER TROF CLEARS KANSAS. WEAKENING LAPSE RATES
AND LESS-FOCUSED LIFT SHOULD KEEP THUNDERSTORMS IN A ISOLATED
NATURE. MODEST COLD AIR ADVECTION AND GOOD MIXING SHOULD STILL
PUSH HIGHS INTO THE UPPER 40S TO LOWER 50S.
DEEP RIDING TO BE THE RULE INTO FRIDAY. HIGHS FRIDAY STILL SOMEWHAT
IN QUESTION WITH EASTERLY WINDS AND INCREASING HIGH CLOUDS BUT KEPT
TEMPS JUST ABOVE MOS VALUES GIVEN THEIR COOL BIAS THIS SEASON.
PRECIP CHANCES RAMP UP AGAIN SATURDAY INTO SATURDAY NIGHT AS THE
NEXT SYSTEM...ENTERING THE PACIFIC NORTHWEST IN RECENT
HOURS...EMERGES FROM THE ROCKIES. INCREASING SOUTH WINDS AND LARGE
SCALE FORCING BRINGS SOME CHANCE FOR SHOWERS BY SATURDAY
AFTERNOON...WITH THE WETTEST PERIOD EXPECTED SATURDAY NIGHT AS THE
LOW SURGES NORTHEAST INTO THE PLAINS. INSTABILITY DOES NOT LOOK
IMPRESSIVE...BUT ENOUGH FORCING MECHANISMS COME TOGETHER FOR SOME
THUNDER POTENTIAL AGAIN. TEMPS STAY WARM ENOUGH FOR AN ALL LIQUID
EVENT UNTIL PERHAPS SUNDAY AFTERNOON AS COLD AIR COMES IN BEHIND THE
LOW...BUT MEASURABLE AMOUNTS SEEM UNLIKELY AT BEST. SECONDARY SYSTEM
WORKING IN BEHIND WILL NEED TO BE WATCHED...BUT THE BULK OF IT
SHOULD REMAIN SOUTH. WILL INCLUDE SMALL OPPORTUNITIES FOR PRECIP
TUESDAY NIGHT IN FAR SOUTHERN AREAS.
65
&&
.AVIATION...
A FEW MORE HOURS OF RAIN EXPECTED AT TAF SITES. FRONT HAS PASSED
MHK AND WILL MOVE THROUGH TOP/FOE AROUND BETWEEN 14/15Z. CIGS
IMPROVE AS RAIN ENDS AND WILL LIFT TO MVFR/VFR IN THE MID MORNING
HOURS BEFORE CLEARING OUT IN THE AFTERNOON. NORTHERLY WINDS REMAIN
OVERNIGHT. 67
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
503 AM EST THU FEB 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT EAST OF THE AREA TODAY. A LOW PRESSURE
SYSTEM WILL APPROACH FROM THE WEST TONIGHT AND BRING A WINTRY MIX
TO PORTIONS OF THE AREA AS IT CROSSES THE REGION ON FRIDAY. HIGH
PRESSURE WILL THEN BUILD IN FROM THE WEST AND ALLOW FOR A DRY
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW WITH 500MB MOISTURE ADVECTING INTO THE AREA FROM
THE WEST. AT THE SURFACE...A 1030MB HIGH IS CENTERED OVER THE
JERSEY COAST...WITH A BROAD AREA OF HIGH PRESSURE EXPANDING
WESTWARD INTO THE AREA. INFRARED SAT IMAGERY INDICATES THAT CLEAR
SKIES HAVE GIVEN WAY TO UPPER LEVEL CLOUD COVERAGE THAT HAS
MOVED INTO THE AREA FROM THE SOUTHWEST.
TODAY...THE SURFACE HIGH WILL CONTINUE TO SHIFT EAST OF THE AREA.
MEANWHILE...FURTHER UPSTREAM...AN INVERTED TROUGH OF LOW PRESSURE
WILL SLIDE INTO THE LOWER GREAT AS ANOTHER LOW DEVELOPS ACROSS THE
SOUTHERN PLAINS. 750-250MB LAYER MOISTURE ASSOCIATED WITH THIS
SYSTEM WILL SPILL INTO THE AREA...WITH SKIES BECOMING OVERCAST.
ALTHOUGH INCREASING CLOUDINESS WILL BE AN INHIBITOR TO HEATING
TODAY...WAA ADVECTION WILL ENSUE AS A LOW-LEVEL RIDGE SHIFTS EAST
OF THE AREA AND THE LOW-LEVEL FLOW BECOMES SOUTHWESTERLY. THE
SURFACE WINDS WILL SHIFT TO SOUTHEASTERLY...FAVORING DOWNSLOPE
ENHANCEMENT WITH WINDS BEGINNING TO PICK UP ON THE WEST-FACING
SLOPES BEGINNING THIS EVENING.
WITH WAA TODAY...TEMPS WILL WARM ABOVE FREEZING ACROSS THE ENTIRE
FORECAST AREA FOR THE FIRST TIME THIS MONTH. HIGHS ARE A MAV/MET
BLEND...RANGING FROM THE MID 30S ALONG THE I-80 CORRIDOR AND
LAUREL HIGHLANDS/ALLEGHENY FRONT TO THE MID 40S IN PORTIONS OF
EASTERN OHIO AND NORTHERN WV.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A MODEL CONSENSUS INDICATES A BROAD NORTHERN STREAM TROUGH
AMPLIFYING AND STRENGTHENING AS ITS AXIS MOVES FROM THE UPPER
MIDWEST ACROSS THE GREAT LAKES ON FRIDAY AND INTO THE UPPER OHIO
VALLEY BY FRIDAY EVENING. AS THE TROUGH SHIFTS EAST OF THE AREA...IT
WILL THEN UNDERGO FURTHER INTENSIFICATION AS ITS ENERGY SHIFTS
EASTWARD AND PHASES WITH A COASTAL LOW. THE TWO FEATURES WILL THEN
BECOME A DEEP...CLOSED LOW OFF THE NEW ENGLAND COAST EARLY ON
SATURDAY. AT THE SURFACE...MODELS REMAIN IN STRONG AGREEMENT WITH
A LOW AND ITS ASSOCIATED COLD FRONT SWEEPING ACROSS THE OHIO
VALLEY THURSDAY NIGHT AND PUSHING ACROSS OUR AREA EARLY ON FRIDAY.
THE UPPER OHIO VALLEY WILL REMAIN DRY THROUGH THE MAJORITY OF
THURSDAY NIGHT IN A DRY SLOT OF WAA AS A WEDGE OF 2-4C 850MB TEMPS
SURGES INTO THE AREA. A SOUTHEASTERLY FLOW IN WAA WILL ENHANCE
DOWNSLOPING AND ALLOW FOR WINDS AT 15-20MPH WITH GUSTS TO 35MPH FOR
THE WESTWARD FACING SLOPES OF CHESTNUT AND LAUREL RIDGES.
THE ONSET OF PRECIP LOOKS TO NOT BE UNTIL AFTER 06Z FRIDAY IN
EASTERN OHIO AND BY AROUND 12Z FOR THE PITTSBURGH METRO AND
LOCATIONS EASTWARD AS FORCING WITH THE COLD FRONT MOVES INTO THE
AREA. POPS QUICKLY INCREASE TO CATEGORICAL WITH THE PASSAGE OF THE
FRONT ON FRIDAY. WITH WAA ONGOING THURSDAY NIGHT...LOWS RANGE FROM
THE LOW TO MID 30S ACROSS THE AREA. WENT WITH A NAM/SREF BLEND FOR
TEMPS ON FRIDAY...WITH HIGHS RANGING FROM THE MID 40S IN NORTH-
CENTRAL WV TO THE MID 30S NORTH OF THE I-80 CORRIDOR.
FOR PRECIP TYPE...THE TIMING OF THE ONSET OF PRECIP ON FRIDAY WILL
BE CRITICAL IN THIS EVENT. MODEL SOUNDINGS INDICATE A MELTING LAYER
IN THE 06Z-15Z FRIDAY TIME FRAME WARM ENOUGH FOR MOST PRECIP TO
REACH THE GROUND AS LIQUID ACROSS THE AREA. THUS...IF PRECIP STARTS
EARLIER THAN 12Z...FREEZING RAIN COULD BECOME AN
ISSUE...PARTICULARLY NORTHEAST OF PITTSBURGH AND ACROSS THE LAUREL
HIGHLANDS/ALLEGHENY FRONT OF WV/PA/MD. IF PRECIP STARTS AFTER
12Z...MOSTLY RAIN IS ANTICIPATED BEFORE THE CHANGE BACK OVER TO SNOW
BEHIND THE FRONT (AFTER 18Z FRIDAY). GIVEN THE SUPPORT OF SREF
PROBABILITIES AND THE 00Z NAM...THE CHANCE OF FREEZING RAIN IS
FORECAST NEAR DAWN FOR THE RIDGES AND LOCATIONS NORTHEAST OF
PITTSBURGH THROUGH UNTIL 14Z. WITH THE POSSIBILITY OF A LIGHT ICING
THERE...THE MENTION OF THIS REMAINS IN THE HWO.
BEHIND THE FRONT ON FRIDAY AND FRIDAY NIGHT...CAA WILL ENSUE WITH 850MB
TEMPS QUICKLY COOLING TO THE -5C TO -10C RANGE. THIS WILL ALLOW PRECIP
TO TURN OVER TO ALL SNOW ACROSS THE AREA FOR FRIDAY EVENING. QPF
IS ANTICIPATED TO BE AROUND A QUARTER OF AN INCH ON FRIDAY...ALTHOUGH
MOST OF THIS SHOULD FALL IN THE FORM OF LIQUID. IN THE WAKE OF THE
FRONT...GENERALLY ANTICIPATE AN INCH OR LESS OF ACCUMULATION ACROSS
THE PITTSBURGH METRO AND SOUTHWARD. A MORE BROAD RANGE OF 1 TO 3
INCHES IS FORECAST NORTH OF PITTSBURGH WITH A LONGER PERIOD OF
SNOW. THERE IS STILL SOME UNCERTAINTY IN THE 12Z-18Z TIME FRAME
FRIDAY IN REGARDS TO HOW FAR WARM WEDGE OF AIR WILL SHIFT
NORTHWARD AND LIMIT SNOW AMOUNTS NORTH OF PITTSBURGH. SNOW WILL
QUICKLY COME TO AN END AFTER 00Z SATURDAY AS LOW-LEVEL RIDGE OF
HIGH PRESSURE BUILDS IN FROM THE WEST AND A MOSTLY FROZEN LAKE
ERIE LACKS AS A MOISTURE SOURCE.
MODELS REMAIN IN AGREEMENT THAT HIGH PRESSURE WILL MOVE OVER THE
AREA ON SATURDAY...ALLOWING FOR A DRY FORECAST AND A PERIOD OF
SUNSHINE DURING THE DAY. DESPITE THE RIDGE BUILDING IN...A
COLD...NORTHERLY FLOW TO THE WEST OF THE COASTAL LOW WILL LIMIT
HIGHS ON SATURDAY TO AROUND 5 DEGREES BELOW NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS HAVE BEEN CONSISTENT IN DVLPMNT OF SPLIT FLOW OVR THE CONUS
THIS WEEKEND WITH RIDGING OVR THE GREAT LAKES AND UPR OH REGIONS.
TEMP MODERATION THUS RMNS ON TRACK WITH READINGS APPROX 10 DEGREES
ABOVE THE AVERAGES FORECAST FOR THE BGNG OF THE NEW WEEK USING
TWEAKED ECMWF GUIDANCE AND PERSISTENCE. INITIALLY DRY WEATHER IS
EXPECTED TO DETERIORATE THOUGH AS LOW PRES DVLPS TWD THE GREAT LAKES.
HIGH AMPLITUDE CNTRL CONUS TROF IS PROGGED TO SLIDE EWD AS MID
WEEK APPROACHES...HENCE TEMPS SHOULD FADE BACK TWD THE SEASONAL
AVERAGES. HOWEVER...POPS WL BE DEPENDENT ON TIMING OF SHRTWVS
MOVING THROUGH THE SWLY FLOW ON THE ERN FLANK OF THAT TROF. HAVE
THUS FORECASTED LATE MON THRU WEDNESDAY POPS NR CHC CLIMO NMBRS
FOR NOW.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
CLEAR SKIES CAN BE EXPECTED OVERNIGHT WITH GENERAL VFR CONDITIONS.
INCREASING MIDDLE CLOUDS ARE FORECAST AFTER SUNRISE INTO THIS
AFTERNOON. LIGHT WINDS CAN BE EXPECTED THROUGH THE TAF PERIOD.
.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
LOW PRES AND THE ASSOCIATED CDFNT WILL DETERIORATE CONDITIONS ONCE
AGAIN FOR THURSDAY NIGHT AND FRIDAY. HIGH PRES WILL RETURN VFR FOR
THE WEEKEND. ANOTHER SYSTEM WILL BRING WIDESPREAD RESTRICTIONS
SUNDAY NIGHT INTO MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
SHORT TERM...WOODRUM
AVIATION...RSD
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
547 AM CST THU FEB 7 2013
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Range (Today through Saturday)...`
Shortwave trough crossing the Continental Divide will track east
across KS/OK this morning and interact with a cold front that
currently stretches from central IA through the TX Panhandle. Modest
southerly low level jet plus generous theta-e advection has resulted
in precipitable water values well above seasonal values. Initial
overnight scattered convection affected areas north of the MO River
and has come and gone. However, an expanding area of showers and
isolated thunderstorms over central and eastern KS will overspread
much of the CWA this morning. Far northwest MO and northeast KS
could very well end up missing most of the rain today. Latest NAM
and RAP qpf have performed best overnight and look like they have
locked into the current radar trend.
The cold front will push southeast and through the CWA, reaching
central MO by mid afternoon. There will be some post frontal rain so
the passage of the front will not herald the end of the rain. That
should come several hours after passage of the front. Temperatures
will initially fall with the passage of the front but mid/late
afternoon clearing across the northwest third of the CWA should
allow a bit of a recovery in temperatures.
High pressure building into the region through Friday will bring
cooler temperatures but still end up being above normal. The high
pressure will head east of the CWA on Saturday as an upper level
ridge progresses east through the Central Plains and MO. The
resulting warm air advection will bring warmer temperatures plus an
increase in clouds. GFS and ECMWF have started to bring in the next
wave of precipitation a bit faster than earlier forecast and could
very well see scattered showers move into east central KS and far
west central MO late in the day. The initial wave of showers will
be elevated and won`t be surprised if the models continue trending
faster in bringing in the warm advection showers.
MJ
Medium Range (Saturday night through Thursday)...
There are two systems of concern in the medium range. The first is a
system that models agree will affect the entire forecast area
Saturday night into Sunday. The second system will move south of the
area Tuesday night bringing the chance for precipitation to the
extreme southern portion of the forecast area.
Models continue to be in good agreement that a closed upper low will
move out of the Great Basin on Saturday night and into the central
Plains. Surface cyclogenesis will also occur over eastern Colorado
Saturday night with a surface low developing and moving into central
Nebraska overnight. A cold front will stretch southward from the
surface low into the southern Plains. Strong warm air advection out
ahead of this front will spread Gulf moisture northward and showers
and thunderstorms will develop from west to east over the forecast
area. The upper level low and attendant surface low will move well
north of the area on Sunday into the Upper Midwest. The GFS is
slightly faster and a little further north than the EC but still in
good agreement. In any case, the local area will remain in the warm
sector and as the cold front moves through the area on Sunday and
showers and thunderstorms will continue to be likely over the
forecast area. Sunday night this system moves into the western Great
Lakes and the cold front pulls east of the forecast area.
Temperatures will be warm on Sunday ahead of the front with highs in
the 50s to near 60. Although there is no really cold air behind this
front, temperatures will be markedly cooler on Monday with highs in
the mid 30s to mid 40s.
The next system of interest will be a upper trough that digs down
the west coast on Monday and develops a closed low over the
southwestern CONUS on Tuesday. The GFS is further north with the
track of the closed low than the EC as it moves into the southern
Plains. The GFS would bring the upper low through Oklahoma and into
southern Missouri Tuesday night bringing snow to the southern half
of the forecast area. The EC would take the upper low across Texas
and into Arkansas leaving the forecast area dry. Opted to keep the
middle of the road solution offered by the initialization and keep
slight chance pops for light snow across the southern zones on
Tuesday night. Temperatures Tuesday will range into the mid 30s to
lower 40s. A warming trend with dry conditions will then be expected
through mid week with highs on Thursday in the 40s.
73
&&
.AVIATION...
For the 12Z TAFs...A large band of showers with MVFR
cigs/visibilities will affect west central MO this morning. The
heaviest rains with pockets of IFR cigs have a better chance to
affect KMKC and pass just south of KMCI. KSTJ will miss the heavier
showers. The rain should have moved east and out of KMCI/KMKC
terminals by around the noon hour.
A cold front will track southeast from northwest MO this morning
resulting in winds switching from the south to north and increasing
into the teens behind the front. Although upstream cigs behind the
front are VFR believe the rain cooled air will allow cigs to remain
in the MVFR category until the stronger northerly winds move in and
mix in drier air. The northerly winds will drop below 10kts by
around sunset with skies clearing.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
425 AM CST THU FEB 7 2013
.DISCUSSION...
Short Range (Today through Saturday)...`
Shortwave trough crossing the Continental Divide will track east
across KS/OK this morning and interact with a cold front that
currently stretches from central IA through the TX Panhandle. Modest
southerly low level jet plus generous theta-e advection has resulted
in precipitable water values well above seasonal values. Initial
overnight scattered convection affected areas north of the MO River
and has come and gone. However, an expanding area of showers and
isolated thunderstorms over central and eastern KS will overspread
much of the CWA this morning. Far northwest MO and northeast KS
could very well end up missing most of the rain today. Latest NAM
and RAP qpf have performed best overnight and look like they have
locked into the current radar trend.
The cold front will push southeast and through the CWA, reaching
central MO by mid afternoon. There will be some post frontal rain so
the passage of the front will not herald the end of the rain. That
should come several hours after passage of the front. Temperatures
will initially fall with the passage of the front but mid/late
afternoon clearing across the northwest third of the CWA should
allow a bit of a recovery in temperatures.
High pressure building into the region through Friday will bring
cooler temperatures but still end up being above normal. The high
pressure will head east of the CWA on Saturday as an upper level
ridge progresses east through the Central Plains and MO. The
resulting warm air advection will bring warmer temperatures plus an
increase in clouds. GFS and ECMWF have started to bring in the next
wave of precipitation a bit faster than earlier forecast and could
very well see scattered showers move into east central KS and far
west central MO late in the day. The initial wave of showers will
be elevated and won`t be surprised if the models continue trending
faster in bringing in the warm advection showers.
MJ
Medium Range (Saturday night through Thursday)...
There are two systems of concern in the medium range. The first is a
system that models agree will affect the entire forecast area
Saturday night into Sunday. The second system will move south of the
area Tuesday night bringing the chance for precipitation to the
extreme southern portion of the forecast area.
Models continue to be in good agreement that a closed upper low will
move out of the Great Basin on Saturday night and into the central
Plains. Surface cyclogenesis will also occur over eastern Colorado
Saturday night with a surface low developing and moving into central
Nebraska overnight. A cold front will stretch southward from the
surface low into the southern Plains. Strong warm air advection out
ahead of this front will spread Gulf moisture northward and showers
and thunderstorms will develop from west to east over the forecast
area. The upper level low and attendant surface low will move well
north of the area on Sunday into the Upper Midwest. The GFS is
slightly faster and a little further north than the EC but still in
good agreement. In any case, the local area will remain in the warm
sector and as the cold front moves through the area on Sunday and
showers and thunderstorms will continue to be likely over the
forecast area. Sunday night this system moves into the western Great
Lakes and the cold front pulls east of the forecast area.
Temperatures will be warm on Sunday ahead of the front with highs in
the 50s to near 60. Although there is no really cold air behind this
front, temperatures will be markedly cooler on Monday with highs in
the mid 30s to mid 40s.
The next system of interest will be a upper trough that digs down
the west coast on Monday and develops a closed low over the
southwestern CONUS on Tuesday. The GFS is further north with the
track of the closed low than the EC as it moves into the southern
Plains. The GFS would bring the upper low through Oklahoma and into
southern Missouri Tuesday night bringing snow to the southern half
of the forecast area. The EC would take the upper low across Texas
and into Arkansas leaving the forecast area dry. Opted to keep the
middle of the road solution offered by the initialization and keep
slight chance pops for light snow across the southern zones on
Tuesday night. Temperatures Tuesday will range into the mid 30s to
lower 40s. A warming trend with dry conditions will then be expected
through mid week with highs on Thursday in the 40s.
73
&&
.AVIATION...
For the 06Z TAFs...Showers have begun to move into northwest
Missouri, ahead of a cold front that will settle through the region
Thursday. Initial onset of storms may be in the MVFR to VFR range,
with some thunderstorm activity, but conditions will deteriorate
during the early morning hours with ceilings and visibilities
dropping into the IFR range before sunrise for many hours. Expect
clearing at the terminals to begin around noon Thursday with north
winds prevailing. Conditions may improve to VFR before sunset, but
confidence in the timing of these out periods is low.
Cutter
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
518 AM CST THU FEB 7 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
PRIMARY AVIATION CONCERNS TODAY ARE COVERAGE OF LOW CLOUDS AND
POSSIBLE VISIBILITY RESTRICTIONS. NORTHERLY LOW LEVEL WINDS WILL
OCCUR TODAY. THESE WILL HELP PULL STRATUS CURRENTLY OVER THE
DAKOTAS AND MINNESOTA DOWN INTO OUR AREA. RECENT RUNS OF THE HRRR
AND RAP SEEM TO HAVE A DECENT HANDLE ON THINGS.
DID NOT WANT TO BE TOO PESSIMISTIC WITH LOW CLOUDS FOR THIS AFTN
AT KOMA AND KLNK SINCE MODELS SUGGEST SOME THINNING OF THE LOW
LEVEL MOIST LAYER. IT APPEARS LOW CLOUDS MAY LINGER AT LEAST INTO
THE EVENING AT KOFK.
MILLER
&&
.PREV DISCUSSION... /ISSUED 355 AM CST THU FEB 7 2013/
DISCUSSION...
CHALLENGING FORECAST TODAY WITH STRATUS SPREADING SOUTH AND
CAUSING POTENTIAL PROBLEMS WITH TEMPERATURE FORECAST...AND
CHALLENGING PRECIPITATION FORECAST FOR WEEKEND WITH STRONG LOW
MOVING THROUGH PLAINS.
CURRENT PATTERN AT THE SURFACE CONSISTED OF A WEAK COLD FRONT
THAT WAS ANALYZED AT 09Z ALMOST THROUGH THE SOUTHEAST CORNER OF
THE FORECAST AREA. WELL BEHIND THE FRONT IN SOUTH DAKOTA WAS AN
EXTENSIVE AREA OF LOW STRATUS...MOVING SOUTH AT AROUND 15 KNOTS.
SHORT TERM MODELS SHOW LITTLE AGREEMENT ON THE EVOLUTION OF THIS
AREA OF STRATUS. GENERALLY THE NAM AND GFS BRING IT INTO THE
FORECAST AREA BUT SUGGEST IT WILL ERODE BY AFTERNOON. HOWEVER THE
HIGHER RESOLUTION HRRR AND RAP ARE MUCH MORE PESSIMISTIC AND PUSH
THE STRATUS AS FAR SOUTH AS THE PLATTE RIVER BY 17Z AND SHOW IT
REMAINING. THIS OF COURSE HAS BIG IMPLICATIONS FOR THE TEMPERATURE
FORECAST. AT THIS TIME WE ARE MORE COMFORTABLE WITH A SOLUTION
CLOSER TO THE HRRR/RAP ESPECIALLY IN NORTHEAST NEBRASKA. THUS HAVE
LOWERED HIGH TEMPERATURES IN NORTHEAST NEBRASKA AND AND KEPT
CLOUDY WORDING THROUGH MUCH OF THE DAY.
TEMPERATURE/CLOUD UNCERTAINTY IS GREATEST FOR LOCATIONS ALONG
INTERSTATE 80 WHERE THE HRRR/RAP SHOW THE STRATUS JUST
APPROACHING. THIS AREA WILL NEED TO BE WATCHED THIS MORNING TO
MONITOR THE SOUTHWARD EXTENT OF THE CLOUD DECK AND THE NEW RUNS OF
THE HRRR AND RAP.
ON FRIDAY THE ATTENTION TURNS TO THE UPPER PATTERN PROGRESSING WITH
A STRONG UPPER LOW MOVING FROM THE WEST THROUGH THE ROCKIES AND
TAKING AIM ON THE PLAINS FOR THE WEEKEND. MODELS AGREE ON LEE SIDE
CYCLOGENESIS BY FRIDAY AFTERNOON AND SOUTH WINDS INCREASING BY
FRIDAY NIGHT. FRIDAY WILL BE DRY...WITH TEMPERATURES MILD AGAIN.
MOST MODELS SHOW DECENT AGREEMENT WITH THE UPPER LOW MOVING OUT OF
COLORADO SATURDAY NIGHT. SOUTHERLY 850 WINDS ARE PROGGED AS HIGH
AS 60 KNOTS OVER THE FORECAST AREA SATURDAY NIGHT AND SUNDAY
MORNING. LOW TEMPERATURES SATURDAY NIGHT WILL BE MILD...WITH
HUMIDITY INCREASING. VERTICAL MOTION AND MOISTURE WILL BE
SUFFICIENT TO TRIGGER SCATTERED SHOWERS ESPECIALLY NORTHERN HALF
OF FORECAST AREA. ON SUNDAY MORNING...THE DRY SLOT WILL BE PUSHING
NORTH THROUGH NEBRASKA. THIS PATTERN HAS THE APPEARANCE OF A
SPRING LOW TOPPED/COLD CORE THUNDERSTORM EVENT. TIGHTLY WRAPPED UP
SURFACE LOW IS PROGGED TO MOVE NEAR EASTERN NEBRASKA JUST EAST OF
CLOSED UPPER LOW...WITH MUCAPE VALUES OF 200-400 J/KG ALONG THE
EDGE OF THE DRY SLOT. CURRENTLY HAVE THUNDER MENTIONED IN FORECAST
AND WILL NEED TO MONITOR FOR ADDITIONAL DETAILS.
AS THE LOW MOVES NORTHEAST...COLD AIR MOVES IN WITH PRECIPITATION
CHANGING TO SNOW ESPECIALLY IN NORTHEAST NEBRASKA. SOME SCENARIOS
SUGGEST A FEW INCHES OF SNOW WITH NORTHWEST WINDS GUSTING TO 40
MPH GIVEN THE NORTHWEST 850 WINDS OF 50 KNOTS OVER FAR NORTHEAST
NEBRASKA. FORECAST COVERS THIS BUT WILL CONTINUE TO ADVERTISE THIS
POSSIBLE WINTER WEATHER EVENT IN HWO. MOST MODELS HAVE THE
PRECIPITATION ON SUNDAY ENDING AS THE LOW RAPIDLY MOVES
NORTHEAST...MEANING THE OMAHA-LINCOLN AREAS AND POINTS SOUTH WOULD
SEE LITTLE SNOW.
NIETFELD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
553 AM CST THU FEB 7 2013
.DISCUSSION.../ISSUED AT 438 AM CST/
STRATUS CONTINUES TO MOVE IN FROM THE NORTH AND EXTENDS WELL INTO
NORTH DAKOTA. WITH WEAK NORTHERLY BOUNDARY LAYER FLOW CONTINUING
THOUGH THE DAY...FEELING IS THIS STRATUS WILL LINGER FOR MOST OF THE
DAY ACROSS THE ENTIRE CWA. THIS IS SHOWN WELL BY THE RAP AND HRRR.
THINKING IS THE STRATUS BEGINS TO ERODE ON THE SOUTHERN EDGE A BIT
BY LATE IN THE DAY...WITH THE BEST CHANCE OF CLEARING TOWARDS THE
MISSOURI RIVER. WITH THE CLOUD COVER...WENT AHEAD AND CONTINUED THE
DOWNWARD TREND WITH HIGHS. HOWEVER WOULD NOT BE SURPRISED IF
SOUTHERN AREAS ARE STILL FORECAST A BIT TOO WARM...BUT DID NOT WANT
TO GO TOO COOL IN CASE THE SUN DOES MANAGE TO COME OUT THIS
AFTERNOON. COULD SEE A BIT OF PATCHY FREEZING DRIZZLE ACROSS HIGHWAY
14 CORRIDOR THIS MORNING WHERE MOISTURE IS DEEPEST...BUT CURRENTLY
NOT EXPECTING ANYTHING WIDESPREAD. AS BOUNDARY LAYER FLOW TURNS MORE
EASTERLY TONIGHT...THINKING STRATUS AND AREAS OF FOG REMAIN OR
REFORM OVER MOST OF THE AREA...ESPECIALLY EAST OF THE JAMES RIVER.
WITH THE CLOUDS AND LIGHT BREEZE...STAYED ON THE WARMER SIDE OF
GUIDANCE FOR LOWS...MAINLY TEENS AND LOWER 20S. HIGHS A BIT TRICKY
ON FRIDAY...WITH STRATUS LIKELY SLOW TO EXIT ACROSS OUR EAST. NAM IS
A BIT OF AN OUTLIER WARMING THE LOW LEVELS QUICKEST...THUS FOLLOWED
CLOSER TO THE ECMWF AND GFS SOLUTIONS...WITH HIGHS IN THE LOW 30S
SOUTHWEST MINNESOTA TO THE LOW 50S NEAR GREGORY COUNTY. A 30 TO 40
KT JET AT 925MB WILL LIKELY PUSH SOUTHERLY WINDS TO NEAR ADVISORY
CRITERIA FRIDAY AFTERNOON WEST OF THE JAMES RIVER. SOUTHERLY WINDS
WILL STAY BLUSTERY ACROSS THE ENTIRE CWA FRIDAY NIGHT...KEEPING LOWS
MAINLY IN THE MID TO UPPER 20S.
ATTENTION THEN TURNS TO A WAVE EJECTING OUT OF THE COLORADO ROCKIES
AND INTO THE PLAINS. MODELS STILL IN FAIRLY GOOD AGREEMENT WITH THIS
SYSTEM...BUT JUST SLIGHT SHIFTS IN THE TRACK WILL HAVE SIGNIFICANT
IMPACTS ON WEATHER TYPE ACROSS OUR CWA. GFS AND ECMWF HAVE TRENDED
SLIGHTLY FURTHER NORTH WITH THE WAVE AND SURFACE LOW...AND THUS
WARMER WITH THEIR TEMPERATURE PROFILES. GFS ENSEMBLE MEAN IS VERY
CLOSE TO THE ECMWF...AND THUS WILL FOLLOW A SOLUTION CLOSEST TO THE
ECMWF FOR NOW. THIS RESULTS IN A SOUTH TO NORTH MOVING AREA OF
MODERATE TO AT TIMES HEAVY PRECIPITATION SATURDAY NIGHT INTO SUNDAY
MORNING...WITH THE DRY SLOT MOVING INTO NORTHWEST IOWA ON
SUNDAY...AND THE HEAVIER PRECIP BAND ACROSS OUR NORTHWEST.
TEMPERATURE PROFILES CONTINUE TO SUPPORT A MAINLY RAIN EVENT ACROSS
NORTHWEST IOWA...WITH EVEN AN ISOLATED THUNDERSTORM POSSIBLE. IN THE
SIOUX FALLS AREA AND VICINITY...IT LOOKS LIKE RAIN
INITIALLY...BEFORE POSSIBLY MIXING OR CHANGING TO SNOW AS
EVAPORATIVE AND DYNAMIC COOLING TAKE PLACE LATE SATURDAY
NIGHT...THEN BACK TO ALL RAIN SUNDAY MORNING AS THE LOW APPROACHES
AND WARM LOW LEVEL TEMPERATURES MOVE IN...AND FINALLY BACK TO SOME
SNOW SUNDAY EVENING AS THE INVERTED TROUGH PUSHES EAST AND COLD AIR
RUSHES IN ON THE BACKSIDE OF THE STORM. THE FURTHER NORTH TRACK ALSO
SUGGESTS THAT SOME RAIN MAY OCCUR AS FAR NORTHWEST AS HURON SATURDAY
EVENING BEFORE COLD AIR MOVES IN OVERNIGHT. OVERALL...THE AREA OF
GREATEST SNOWFALL POTENTIAL REMAINS FROM CHAMBERLAIN TO HURON TO
JUST NORTH OF BROOKINGS AND MARSHALL...WHERE 6 OR MORE INCHES SEEM
POSSIBLE. OTHER ISSUE WILL BE STRONG NORTHWEST WINDS LATER SUNDAY
AFTERNOON INTO SUNDAY NIGHT ON THE COLD SIDE OF THE INVERTED TROUGH.
ADVISORY LEVEL WINDS SEEM PROBABLE...AND THIS COMBINED WITH THE SNOW
MAY CAUSE BLIZZARD OR NEAR BLIZZARD CONDITIONS IN THE ABOVE AREA
WHERE SNOW AMOUNTS WILL BE HIGHEST. ACCUMULATIONS SHOULD DROP OFF AS
YOU HEAD SOUTHEAST OF THIS REGION...WHERE RAIN SHOULD HOLD AMOUNTS
DOWN. AGAIN...ANY SHIFT IN STORM TRACK WILL SHIFT THE ABOVE
DESCRIPTION. FOR EXAMPLE...THE GEM IS BY FAR THE FURTHEST SOUTH
SOLUTION SHOWING THE HEAVIEST SNOW ALONG THE INTERSTATE 90 CORRIDOR.
THIS OUTLIER SOLUTION IS BEING DISCARDED AT THIS TIME...BUT FUTURE
TRENDS IN MODELS SOLUTIONS WILL HAVE TO BE MONITORED. /CHENARD
WITH CYCLONIC FLOW THROUGHOUT THE ATMOSPHERE AND A SECOND WEAK WAVE
MOVING ACROSS WESTERN MINNESOTA...LIKELY TO BE A LOT OF CLOUDS EAST
OF I29 MONDAY...ESPECIALLY EARLY IN THE DAY. THERE ALSO BE ENOUGH
LIFT TO PRODUCE SOME FLURRIES OR LIGHT SNOW...PRIMARILY IN SOUTHWEST
MINNESOTA. ANY ACCUMULATIONS WOULD BE LESS THAN AN INCH IF THERE IS
ANY. HOWEVER...925 MB WINDS IN ALL MODELS ARE STILL FROM 30 TO 40
KTS THROUGH MIDDAY BEFORE WEAKENING AS A RIDGE MOVES IN FROM THE
WEST AND WINDS DECREASE. WITH A FAIRLY WELL MIXED BOUNDARY
LAYER...WOULD EXPECT SUSTAINED WINDS OVER 20 MPH WITH GUSTS AGAIN
OVER 30 MPH FOR MUCH OF THE DAY EAST OF I29.
AFTER MONDAY THERE ARE DIFFERENCES BETWEEN THE ECMWF AND GFS IN HOW
FAST THE SURFACE RIDGE MOVES EAST AND THEN THE DEGREE OF WARMING
TOWARD THE MIDDLE OF NEXT WEEK. THE ECMWF IS SLOWER WITH THIS RIDGE
AND ALSO WARMER BY NEXT WEDNESDAY WITH THE POSSIBILITY OF
APPROACHING OR EVEN RISING ABOVE FREEZING WEDNESDAY AFTERNOON IN
MOST OF THE AREA. THE GFS WOULD KEEP TEMPERATURE WITHIN A COUPLE OF
DEGREES OF NORMAL. WITH UNCERTAINTY IN BOTH THE DEGREE OF WARMING
AND THE AMOUNT OF SNOWCOVER THAT WILL EXIST...STAYED WITH A COOLER
CONSENSUS FORECAST WITH HIGHS IN THE 20S TO LOWER 30S ON
TUESDAY...AND ABOUT 3 TO 5 DEGREES WARMER ON WEDNESDAY. TUESDAY AND
WEDNESDAY ARE EXPECTED TO BE DRY./SCHUMACHER
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
STRATUS HAS SPREAD ACROSS MOST OF THE AREA THIS MORNING. WITH
PERSISTENT NORTHERLY FLOW THROUGH THE DAY EXPECT STRATUS TO CONTINUE
ADVECTING SOUTH WELL INTO NEBRASKA AND THIS WILL KEEP IFR CIGS OVER
THE AREA THROUGH 00Z FRIDAY. THERE IS A SMALL CHANCE THAT WARMING
THIS AFTERNOON COULD TEMPORARILY RAISE CIGS ABOVE 1000 FT BUT THE
FEBRUARY SUN IS STILL PRETTY WEAK AND THE STRATUS IS A FEW THOUSAND
FEET THICK SO DO NOT BELIEVE SURFACE WARMING WILL BE ENOUGH TO LIFT
CEILINGS MORE THAN A COUPLE HUNDRED FEET. WITH THE RIDGE AXIS MOVING
OVER TONIGHT...THERE WILL BE NO ADVECTION OF DRYER AIR TO ERODE
CLOUDS. INSTEAD CLOUDS WILL LIKELY PERSIST UNTIL SOUTHERLY FLOW
INCREASES LATE TONIGHT AND FRIDAY MORNING. SO KEPT IFR CONDITIONS IN
KFSD AND KSUX THROUGH 12Z AND DID NOT CLEAR OUT KHON UNTIL LATE
TONIGHT. IN ADDITION...LIGHT FOG WILL LIKELY LIMIT VSBYS BOTH THIS
MORNING AND AGAIN OVERNIGHT TO 3 TO 5 SM. /SCHUMACHER
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
438 AM CST THU FEB 7 2013
.DISCUSSION.../ISSUED AT 438 AM CST/
STRATUS CONTINUES TO MOVE IN FROM THE NORTH AND EXTENDS WELL INTO
NORTH DAKOTA. WITH WEAK NORTHERLY BOUNDARY LAYER FLOW CONTINUING
THOUGH THE DAY...FEELING IS THIS STRATUS WILL LINGER FOR MOST OF THE
DAY ACROSS THE ENTIRE CWA. THIS IS SHOWN WELL BY THE RAP AND HRRR.
THINKING IS THE STRATUS BEGINS TO ERODE ON THE SOUTHERN EDGE A BIT
BY LATE IN THE DAY...WITH THE BEST CHANCE OF CLEARING TOWARDS THE
MISSOURI RIVER. WITH THE CLOUD COVER...WENT AHEAD AND CONTINUED THE
DOWNWARD TREND WITH HIGHS. HOWEVER WOULD NOT BE SURPRISED IF
SOUTHERN AREAS ARE STILL FORECAST A BIT TOO WARM...BUT DID NOT WANT
TO GO TOO COOL IN CASE THE SUN DOES MANAGE TO COME OUT THIS
AFTERNOON. COULD SEE A BIT OF PATCHY FREEZING DRIZZLE ACROSS HIGHWAY
14 CORRIDOR THIS MORNING WHERE MOISTURE IS DEEPEST...BUT CURRENTLY
NOT EXPECTING ANYTHING WIDESPREAD. AS BOUNDARY LAYER FLOW TURNS MORE
EASTERLY TONIGHT...THINKING STRATUS AND AREAS OF FOG REMAIN OR
REFORM OVER MOST OF THE AREA...ESPECIALLY EAST OF THE JAMES RIVER.
WITH THE CLOUDS AND LIGHT BREEZE...STAYED ON THE WARMER SIDE OF
GUIDANCE FOR LOWS...MAINLY TEENS AND LOWER 20S. HIGHS A BIT TRICKY
ON FRIDAY...WITH STRATUS LIKELY SLOW TO EXIT ACROSS OUR EAST. NAM IS
A BIT OF AN OUTLIER WARMING THE LOW LEVELS QUICKEST...THUS FOLLOWED
CLOSER TO THE ECMWF AND GFS SOLUTIONS...WITH HIGHS IN THE LOW 30S
SOUTHWEST MINNESOTA TO THE LOW 50S NEAR GREGORY COUNTY. A 30 TO 40
KT JET AT 925MB WILL LIKELY PUSH SOUTHERLY WINDS TO NEAR ADVISORY
CRITERIA FRIDAY AFTERNOON WEST OF THE JAMES RIVER. SOUTHERLY WINDS
WILL STAY BLUSTERY ACROSS THE ENTIRE CWA FRIDAY NIGHT...KEEPING LOWS
MAINLY IN THE MID TO UPPER 20S.
ATTENTION THEN TURNS TO A WAVE EJECTING OUT OF THE COLORADO ROCKIES
AND INTO THE PLAINS. MODELS STILL IN FAIRLY GOOD AGREEMENT WITH THIS
SYSTEM...BUT JUST SLIGHT SHIFTS IN THE TRACK WILL HAVE SIGNIFICANT
IMPACTS ON WEATHER TYPE ACROSS OUR CWA. GFS AND ECMWF HAVE TRENDED
SLIGHTLY FURTHER NORTH WITH THE WAVE AND SURFACE LOW...AND THUS
WARMER WITH THEIR TEMPERATURE PROFILES. GFS ENSEMBLE MEAN IS VERY
CLOSE TO THE ECMWF...AND THUS WILL FOLLOW A SOLUTION CLOSEST TO THE
ECMWF FOR NOW. THIS RESULTS IN A SOUTH TO NORTH MOVING AREA OF
MODERATE TO AT TIMES HEAVY PRECIPITATION SATURDAY NIGHT INTO SUNDAY
MORNING...WITH THE DRY SLOT MOVING INTO NORTHWEST IOWA ON
SUNDAY...AND THE HEAVIER PRECIP BAND ACROSS OUR NORTHWEST.
TEMPERATURE PROFILES CONTINUE TO SUPPORT A MAINLY RAIN EVENT ACROSS
NORTHWEST IOWA...WITH EVEN AN ISOLATED THUNDERSTORM POSSIBLE. IN THE
SIOUX FALLS AREA AND VICINITY...IT LOOKS LIKE RAIN
INITIALLY...BEFORE POSSIBLY MIXING OR CHANGING TO SNOW AS
EVAPORATIVE AND DYNAMIC COOLING TAKE PLACE LATE SATURDAY
NIGHT...THEN BACK TO ALL RAIN SUNDAY MORNING AS THE LOW APPROACHES
AND WARM LOW LEVEL TEMPERATURES MOVE IN...AND FINALLY BACK TO SOME
SNOW SUNDAY EVENING AS THE INVERTED TROUGH PUSHES EAST AND COLD AIR
RUSHES IN ON THE BACKSIDE OF THE STORM. THE FURTHER NORTH TRACK ALSO
SUGGESTS THAT SOME RAIN MAY OCCUR AS FAR NORTHWEST AS HURON SATURDAY
EVENING BEFORE COLD AIR MOVES IN OVERNIGHT. OVERALL...THE AREA OF
GREATEST SNOWFALL POTENTIAL REMAINS FROM CHAMBERLAIN TO HURON TO
JUST NORTH OF BROOKINGS AND MARSHALL...WHERE 6 OR MORE INCHES SEEM
POSSIBLE. OTHER ISSUE WILL BE STRONG NORTHWEST WINDS LATER SUNDAY
AFTERNOON INTO SUNDAY NIGHT ON THE COLD SIDE OF THE INVERTED TROUGH.
ADVISORY LEVEL WINDS SEEM PROBABLE...AND THIS COMBINED WITH THE SNOW
MAY CAUSE BLIZZARD OR NEAR BLIZZARD CONDITIONS IN THE ABOVE AREA
WHERE SNOW AMOUNTS WILL BE HIGHEST. ACCUMULATIONS SHOULD DROP OFF AS
YOU HEAD SOUTHEAST OF THIS REGION...WHERE RAIN SHOULD HOLD AMOUNTS
DOWN. AGAIN...ANY SHIFT IN STORM TRACK WILL SHIFT THE ABOVE
DESCRIPTION. FOR EXAMPLE...THE GEM IS BY FAR THE FURTHEST SOUTH
SOLUTION SHOWING THE HEAVIEST SNOW ALONG THE INTERSTATE 90 CORRIDOR.
THIS OUTLIER SOLUTION IS BEING DISCARDED AT THIS TIME...BUT FUTURE
TRENDS IN MODELS SOLUTIONS WILL HAVE TO BE MONITORED. /CHENARD
WITH CYCLONIC FLOW THROUGHOUT THE ATMOSPHERE AND A SECOND WEAK WAVE
MOVING ACROSS WESTERN MINNESOTA...LIKELY TO BE A LOT OF CLOUDS EAST
OF I29 MONDAY...ESPECIALLY EARLY IN THE DAY. THERE ALSO BE ENOUGH
LIFT TO PRODUCE SOME FLURRIES OR LIGHT SNOW...PRIMARILY IN SOUTHWEST
MINNESOTA. ANY ACCUMULATIONS WOULD BE LESS THAN AN INCH IF THERE IS
ANY. HOWEVER...925 MB WINDS IN ALL MODELS ARE STILL FROM 30 TO 40
KTS THROUGH MIDDAY BEFORE WEAKENING AS A RIDGE MOVES IN FROM THE
WEST AND WINDS DECREASE. WITH A FAIRLY WELL MIXED BOUNDARY
LAYER...WOULD EXPECT SUSTAINED WINDS OVER 20 MPH WITH GUSTS AGAIN
OVER 30 MPH FOR MUCH OF THE DAY EAST OF I29.
AFTER MONDAY THERE ARE DIFFERENCES BETWEEN THE ECMWF AND GFS IN HOW
FAST THE SURFACE RIDGE MOVES EAST AND THEN THE DEGREE OF WARMING
TOWARD THE MIDDLE OF NEXT WEEK. THE ECMWF IS SLOWER WITH THIS RIDGE
AND ALSO WARMER BY NEXT WEDNESDAY WITH THE POSSIBILITY OF
APPROACHING OR EVEN RISING ABOVE FREEZING WEDNESDAY AFTERNOON IN
MOST OF THE AREA. THE GFS WOULD KEEP TEMPERATURE WITHIN A COUPLE OF
DEGREES OF NORMAL. WITH UNCERTAINTY IN BOTH THE DEGREE OF WARMING
AND THE AMOUNT OF SNOWCOVER THAT WILL EXIST...STAYED WITH A COOLER
CONSENSUS FORECAST WITH HIGHS IN THE 20S TO LOWER 30S ON
TUESDAY...AND ABOUT 3 TO 5 DEGREES WARMER ON WEDNESDAY. TUESDAY AND
WEDNESDAY ARE EXPECTED TO BE DRY./SCHUMACHER
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
IFR TO MVFR CEILINGS NORTH OF A HON-MML LIKE AT 06Z WILL SAG SOUTH
ACROSS THE CWA THROUGH THE NIGHT AND INTO THURSDAY MORNING.
CONDITIONS MAY BECOME VFR SOUTH OF I90 AFTER 18Z BUT LIKELY TO
REMAIN MVFR TO THE NORTH THROUGH 06Z FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
844 AM PST THU FEB 7 2013
.SHORT TERM DISCUSSION...
A POTENTIALLY ACTIVE WEATHER DAY IS SHAPING UP FOR INTERIOR NORCAL
WITH MULTIPLE WEATHER CONCERNS INCLUDING THUNDERSTORMS THIS
AFTERNOON IN THE CENTRAL VALLEY AND LOWER-ELEVATION SNOW IN THE
SIERRA THIS EVENING.
CURRENT WATER VAPOR IMAGERY SHOWS A BROAD CIRCULATION CENTER NEAR
VANCOUVER ISLAND BC DROPPING SOUTHWARD ALONG THE WEST COAST. A
MOISTURE PLUME WRAPPING AROUND ITS BASE AND INTO NORCAL IS QUICKLY
SHIFTING SOUTHWARD. DRIER BUT MORE UNSTABLE AIR LIES JUST UPSTREAM
AND HAS ALREADY REACHED A UKIAH-CHICO LINE. VIS IMAGERY SHOWS
CLEARING OVER THE COASTAL MOUNTAINS WITH SCATTERED CONVECTIVE
CLOUDS...ALTHOUGH NO CLOUD-TO-GROUND LIGHTNING STRIKES YET. AT THE
SURFACE...THE BEALE RADAR SHOWS THAT PRECIP WITH THE SURFACE FRONT
IS NEARING THE SAC METRO AREA...WHILE THE NORTHERN EDGE HAS
ALREADY PASSED REDDING. LOOKING THROUGH THE VARIOUS MODELS THIS
MORNING...THE RUC CURRENTLY HAS THE BEST HANDLE ON TIMING OF THE
PRECIP...SO WILL BE LEANING ON THAT MODEL.
CONVECTIVE POTENTIAL IS LOOKING BETTER FOR TODAY WITH THE SURFACE
FRONT SPEEDING UP AND LIKELY PUSHING EAST OF THE SAC VALLEY BY THE
AFTERNOON PER THE LATEST RUC. BIGGEST QUESTION WILL BE HOW MUCH
CLEARING AND SUBSEQUENT WARMING WE CAN GET. IN BUFKIT...THIS
MORNING`S NAM WARMS TEMPS UP NICELY IN THE CENTRAL/SOUTHERN SAC
VALLEY AND THUS HAS A JUICY SOUNDING (FOR OUR AREA) OVER
SACRAMENTO BY 4 THIS AFTERNOON WITH 300J/KG CAPE EXTENDING UP TO
18KFT AGL AND GOOD 0-6KM SHEAR. THIS GETS INTO THE RANGE THAT LOCAL
RESEARCH HAS CONNECTED WITH EF0 TORNADOES. EXPECTING SMALL HAIL AT LEAST
GIVEN THAT MOST OF THE CAPE IS ABOVE THE FREEZING LEVEL. ALL
MODELS SHOW GOOD 0-1 AND 0-6KM SPEED SHEAR THANKS TO SURFACE WINDS
REMAINING RELATIVELY LIGHT EVEN AFTER THE FRONT PASSES WHILE
WESTERLY WINDS ALOFT PICK UP.
THE OTHER CONCERN IS THE FIRST SNOW IN A WEEK OR SO OVER THE
SIERRA AND FOOTHILLS. THE HMT SNOW LEVEL SENSOR AT SHASTA LAKE INDICATES
SNOW LEVELS DOWN TO 3000FT ON THE BACKSIDE OF THE FRONT WHILE CAMS
SHOW ACCUMULATING SNOW DOWN TO 3500 FEET...WHICH IS IN GOOD
AGREEMENT WITH CURRENT FORECAST. WINTER WEATHER ADVISORY OVER THE
MOUNTAINS LOOKS GOOD FOR NOW...WILL PROBABLY UPDATE THE TIMING
WITH THE AFTERNOON PACKAGE AS WE MAY WANT TO CLEAR OUT THE COASTAL
MOUNTAINS SOONER.
PREVIOUS FORECAST LOOKS GOOD SO NO MORNING UPDATES NEEDED. THE
DISCUSSION BELOW PROVIDES AN EXCELLENT OVERVIEW OF THE SITUATION.
-DVC
.PREVIOUS DISCUSSION...ISSUED 522 AM PST...
FRONTAL BAND NOW MOVING INTO NORTHWEST CALIFORNIA BRINGING LIGHT
SHOWERS TO WESTERN SHASTA COUNTY AT THIS TIME. THIS FRONT IS
FORECAST TO MAKE ITS WAY EASTWARD DURING THE DAY WITH THE LATEST
NAM12 INDICATING FRONTAL PASSAGE THROUGH THE REDDING AREA AND
TRAILING BACK TO THE BAY AREA BY AROUND 00Z. PRECIPITATION FROM
THIS SYSTEM WILL BE RELATIVELY LIGHT BUT IT WILL USHER IN MUCH
COOLER AIR FOR DAYTIME HIGHS 10 OR MORE DEGREES BELOW WEDNESDAY
HIGHS. DROPPING SNOW LEVELS WILL DROP SNOW DOWN INTO THE FOOTHILLS
LATER TODAY WITH ENOUGH NUISANCE SNOWFALL TO KEEP WINTER WEATHER
ADVISORIES FOR THE MOUNTAINS AND HIGHER FOOTHILLS IN PLACE. COLD
UPPER LOW WILL BEGIN PUSHING INTO NORCAL THIS AFTERNOON AND MAY
CREATE MOST SIGNIFICANT SHORT TERM WEATHER CONCERN. LATEST NAM AND
GFS BOTH SHOWING NEGATIVE LI VALUES THROUGHOUT THE SACRAMENTO
VALLEY THIS AFTERNOON. INSTABILITY COMBINED WITH MOISTURE AND LIFT
WILL MAKE ISOLATED THUNDERSTORMS IN THIS REGION A GOOD
POSSIBILITY. 06Z MU CAPE FROM NAM12 SHOWS AREA OF MOST INSTABILITY
OVER THE CENTRAL SACRAMENTO VALLEY THIS AFTERNOON SO THIS LIKELY
TO BE AREA OF HIGHEST THUNDERSTORM POTENTIAL. 0-1 AND 0-6KM SHEAR
IN THIS REGION DOES PLACE IT WITHIN HISTORICAL REALM OF WEAK
TORNADIC ACTIVITY. THERE ARE SEVERAL LIMITING FACTORS HOWEVER.
CAPE IS SOMEWHAT LIMITED AT BETWEEN 200 AND 300 J/KG AND LOW LEVEL
LAPS RATES ARE NOT IDEAL AS WELL. IN ADDITION...JET LOCATION
AROUND BOTTOM OF LOW A BIT TOO FAR SOUTH TO FULLY IMPACT THE
CENTRAL SACRAMENTO VALLEY. FINALLY...MODELS OVER THE LAST 24 HOURS
HAVE SLOWED THE INITIAL FRONT A BIT SO CLOUD COVER COULD REMAIN IN
PLACE ALL DAY LIMITING SURFACE HEATING. BELIEVE THESE FACTORS
TOGETHER WILL INHIBIT SEVERE THUNDERSTORM DEVELOPMENT BUT MINOR
CHANGES COULD MAKE SEVERE WEATHER MORE LIKELY AND AN EYE WILL NEED
TO BE KEPT ON THE SACRAMENTO VALLEY TODAY. HAVE ADDED A THREAT OF
THUNDERSTORMS TO THE FOOTHILLS THIS AFTERNOON SINCE THE FRONTAL
BAND IS FORECAST TO BE THERE LATE THIS AFTERNOON DURING MAXIMUM
HEATING.
UPPER LOW CENTER SHIFTS SOUTH OF CWA BY FRIDAY MORNING AND BY
FRIDAY AFTERNOON ANY PRECIP THREAT SHOULD BE LIMITED TO THE
SIERRA...FOOTHILLS AND SAN JOAQUIN VALLEY. A LITTLE MORE SUN WILL
BRING WARMING TO SOME AREAS. WRAP AROUND MOISTURE WILL KEEP SHOWER
THREAT GOING OVER THE NORTHERN SIERRA THROUGH SATURDAY MORNING. BY
SATURDAY AFTERNOON...DRY NORTHERLY FLOW WILL TAKE OVER WITH STILL
MORE WARMING EXPECTED. A MODERATE NORTHERLY SURFACE GRADIENT WILL
BRING BREEZY NORTH WINDS ACROSS THE ENTIRE CWA. THESE WINDS WILL
DROP OFF ON SUNDAY AS LARGE UPPER RIDGE OF HIGH PRESSURE PUSHES
INLAND OVER THE WEST COAST. SUNDAY WILL BRING THE BEGINNING OF A
WARMING TREND EXPECTED TO LAST INTO MID WEEK.
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
DRY WEATHER CONTINUES THROUGH THE EXTENDED PERIOD AS HIGH PRESSURE
OVER THE EASTERN PACIFIC BUILDS INTO CALIFORNIA. SUNDAY MAY
CONTINUE TO BRING LOCALLY BREEZY NORTHEAST WINDS TO FAVORABLY
ORIENTED CANYONS OF THE SIERRA. THESE WINDS SHOULD BEGIN TO TAPER
OFF BY EARLY NEXT WEEK. MODEST WARMING TREND SHOULD CONTINUE AT
LEAST INTO EARLY NEXT WEEK AS THE UPPER RIDGE SHIFTS OVERHEAD.
THIS COULD POTENTIALLY LEAD TO SOME PATCHY MORNING FOG IN THE
VALLEYS. CONFIDENCE DROPS BY THE MIDDLE OF NEXT WEEK WITH THE
MODEL HANDLING OF SMALL-SCALE FEATURES. DANG
&&
.AVIATION...
COLD FRONT AND BAND OF SHOWERS N OF THE I-80 CORRIDOR FORECAST TO
MOVE SEWD INTO THE I-80 CORRIDOR BY 18Z- 20Z...CONTINUING INTO THE
AFTERNOON AND EARLY EVENING. WDSPRD MVFR CIGS AND VSBYS EXPECTED
WITH BAND OF SHOWERS. LIFR VSBYS IN THE SCK/MOD AREAS EXPECTED TO
IMPROVE 18Z-20Z WITH APPROACHING FRONT AND BAND OF SHOWERS. CIGS
LOWERING TO WDSPRD IFR/LIFR OVER MTNS IN SNOW...WITH SNOW LEVEL
LOWERING TO 3 KFT DURING THE DAY AND EARLY EVENING FROM N TO S.
BEHIND THE FRONT ISOLATED TSRA- TSRAGS WILL BE POSSIBLE THROUGH
EARLY EVENING. SOUTHERLY WINDS 5-15 KT THROUGH ABOUT 00Z SHOULD
BECOME LIGHT THIS EVENING.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 AM PST FRIDAY BURNEY BASIN /
EASTERN SHASTA COUNTY...MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO
NORTHERN LAKE COUNTY...NORTHEAST FOOTHILLS/SACRAMENTO VALLEY...
SHASTA LAKE AREA / NORTHERN SHASTA COUNTY...WESTERN PLUMAS
COUNTY/LASSEN PARK.
WINTER WEATHER ADVISORY UNTIL 10 AM PST FRIDAY WEST SLOPE
NORTHERN SIERRA NEVADA.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM PST
FRIDAY MOTHERLODE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
206 PM CST THU FEB 7 2013
.MESOSCALE DISCUSSION...
106 PM CST
WE HAVE OPTED TO UPGRADE LAKE AND MCHENRY COUNTIES TO A WINTER
STORM WARNING. SHORT TERM GUIDANCE AND RADAR TRENDS CONTINUES TO
INDICATE HEAVY SNOW RATES IN ACROSS LAKE AND MCHENRY COUNTIES. WE
HAVE HAD REPORTS OF UP TO 2 INCHES IN BEACH PARK WITHIN A COUPLE
HOURS.
A RATHER IMPRESSIVE SHORT WAVE...CURRENTLY DIGGING SOUTHEAST ACROSS
EASTERN NEBRASKA AND INTO WESTERN IOWA...WILL LINK UP WITH A
STRENGTHENING BAND OF MID LEVEL FRONTOGENESIS AND NEGATIVE EPV TO
RESULT IN A BAND OF VERY HEAVY SNOW ACROSS NORTHEASTERN ILLINOIS
THROUGH THE AFTERNOON. THE RAIN SHOULD BEGIN TO QUICKLY TRANSITION
TO
SNOW ACROSS THE CHICAGO AREA...MAINLY ALONG AND NORTH OF THE
INTERSTATE 80 CORRIDOR BY MID AFTERNOON AS COLUMN COOL OCCURS IN
RESPONSE TO THE STRONG FRONTOGENETIC CIRCULATION. SOME OF THE LAST
AMDAR SOUNDINGS OUT OF ORD AND MDW...ONLY INDICATE A MAX TEMP OF
AROUND +1 AROUND 946 MB. SO IT WILL NOT TAKE MUCH TO TIP THE SCALES
IN FAVOR FOR SNOW. ONCE THE SNOW STARTS EXPECT HEAVY SNOW UP TO AN
INCH PER HOUR AT TIMES THROUGH THE EVENING COMMUTE. LESSER AMOUNTS
OF SNOW ARE EXPECTED FARTHER SOUTH TOWARDS THE I 80 CORRIDOR.
HOWEVER...IT MAY TAKE SOME TIME TO CHANGE OVER THIS FAR SOUTH...THUS
1 TO 3 INCHES ARE STILL POSSIBLE IN THIS AREA AS WELL INTO THE
EVENING.
SNOW AMOUNTS OF 2 TO 4 INCHES ARE LIKELY NORTH OF I-88 WITH 4 TO 8
INCHES LIKELY ACROSS LAKE AND MCHENRY COUNTIES.
KJB
&&
.DISCUSSION...
1117 AM CST
HAVE EXPANDED WINTER WEATHER ADVISORY TO INCLUDE WINNEBAGO AND BOONE
COUNTIES AND THE I-88 CORRIDOR.
RECENT AMDAR SOUNDINGS OUT OF ORD/MDW SHOW WARM LAYER UP TO JUST
UNDER +3C BETWEEN 950 AND 900 MB...WHICH LATEST RAP HAS A DECENT
HANDLE ON...RESULTING IN PLAIN RAIN FOR THE CITY AND POINTS SOUTH.
HOWEVER...TEMPERATURES AT THAT LEVEL ACROSS THE NORTHERN TIER OF
COUNTIES ARE DOWN BELOW 1C...ALREADY SUPPORTING A CHANGE TO SNOW
WITH THE CURRENT OB AT KUGN DOWN TO 1/2 MILE VSBY IN SNOW. ALSO
RECEIVED A REPORT OF SNOW STARTING TO ACCUMULATE IN WAUKEGAN AND
ZION IL AND A CHANGEOVER IN CHERRY VALLEY IL. WITH THIS IN
MIND...WILL START RIGHT OUT THE GATE WITH AN ADVISORY FOR WINNEBAGO
BOONE MCHENRY AND LAKE COUNTIES. ALSO BUMPED UP SNOW AMOUNTS TO 2 TO
5 INCHES FOR THE NORTHERN TIER GIVEN THE EARLIER START TIME TO THE
SNOW.
FARTHER TO THE SOUTH...FOR THE I-88 CORRIDOR...THE RAP ALSO SHOWS
THE 950 TO 900MB LAYER QUICKLY COOLING OFF BELOW 0C THROUGH THE
AFTERNOON INDICATIVE OF DYNAMIC COOLING. SO THESE AREAS SHOULD
CHANGE BACK OVER TO SNOW AND SEE DECENT SNOWFALL RATES GIVEN THE
FORCING AT HAND AND THE FACT THAT SURFACE TEMPERATURES EVEN NOW ARE
HOVERING JUST ABOVE FREEZING. FORECAST AMOUNTS WILL BE MARGINAL FOR
AN ADVISORY AT ROUGHLY 2 TO 4 INCHES...BUT SINCE THE RUSH HOUR WILL
BE IMPACTED...FELT IT WAS PRUDENT TO ISSUE ONE STARTING AT 20Z.
INCLUDED OGLE...DEKALB...KANE...DUPAGE AND COOK IN THIS NEW
ADVISORY...BUT KEEP IN MIND THAT THERE WILL LIKELY BE A GRADIENT
FROM NORTH TO SOUTH ACROSS DEKALB THROUGH COOK WHERE THE NORTHERN
PORTIONS WILL BE SEEING THE MORE SIGNIFICANT IMPACTS FROM THE SNOW.
WITH A GOOD FGEN BAND COINCIDENT WITH STRONG LIFT NOTED ON MUCH OF
THE GUIDANCE PIVOTING ACROSS THE CWA AND BEING LOCATED OVER
NORTHEAST ILLINOIS INCLUDING CHICAGO BY THE EARLY EVENING...ALSO
CONCERNED THAT HEAVY SNOWFALL RATES COULD LEAD TO HIGHER TOTALS THAN
THE 3 TO 5 INDICATED IN LAKE AND MCHENRY ALONG THE I-88 CORRIDOR IN
NORTHEAST ILLINOIS. WILL CONTINUE TO ASSESS FOR ANY FURTHER UPDATES
NEEDED. BUT IN SUM...THE AFTERNOON COMMUTE IS LIKELY TO BE PRETTY
MESSY...ESPECIALLY FOR THE NORTHERN PART OF THE METRO.
RC/KJB
//PREV DISCUSSION...
553 AM CST
PRECIPITATION HAS OVERSPREAD NORTHERN IL EARLY THIS MORNING WITH
TEMPERATURES INITIALLY ABOVE FREEZING. AS PRECIPITATION BECAME A
LITTLE STEADIER...TEMPERATURES HAVE FALLEN TO OR A DEGREE BELOW
FREEZING. THIS HAS RESULTED IN FREEZING RAIN BEING REPORTED ACROSS
MANY OF MY FAR NORTHEAST ILLINOIS AREAS...MAINLY ALONG AND NORTH
OF I-88. THUS HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY UNTIL
10 AM...WHICH IS THE TIME THAT TEMPS SHOULD PUSH ABOVE THE
FREEZING POINT WITH RISING DEW POINTS. PRECIPITATION AT THAT POINT
SHOULD TRANSITION OVER TO ALL RAIN.
BEACHLER
//PREV DISCUSSION...
337 AM CST
VERY DYNAMIC AND CHALLENGING WEATHER SYSTEM CONTINUES TO SLIDE EAST
FROM THE CENTRAL PLAINS TODAY. SFC TEMPS HAVE REMAINED MILD
OVERNIGHT IN THE LOW/MID 30S...WITH DEW POINTS HOVERING AROUND 30
DEG IN MANY LOCATIONS. IR IMAGERY INDICATES CONSIDERABLE CLOUD
COVER...WITH THE COLDEST CLOUDS ORIENTED FROM CENTRAL IOWA NORTHEAST
THROUGH CENTRAL WISCONSIN INTO NORTHERN LOWER MICHIGAN. EARLY THIS
MORNING CONSIDERABLE LIGHTING WAS NOTED ACROSS KANSAS AND CENTRAL
MISSOURI...INDICATING THAT CONSIDERABLE LIFT/UPGLIDE WAS OCCURRING
IN THIS AREA. IN ADDITION TO THE THUNDERSTORM ACTIVITY UPSTREAM OF
NORTHERN IL/NORTHWEST IN...WAS TEMPS IN THE LOW/MID 40S ACROSS
SOUTH CENTRAL IOWA EARLY THIS MORNING. WARM/MOIST AIR CONTINUES TO
BE
TRANSPORTED NORTH FROM THE WESTERN GULF OF MEXICO AHEAD OF THE
SHORTWAVE...WHICH WILL PLAY A LARGE ROLE IN KEEPING THE BULK OF THE
PRECIP AT THE ONSET AS LIQUID. HOWEVER...A FEW SITES CONTINUE TO
SHOW TEMPS AROUND THE FREEZING MARK. THUS IT IS CONCEIVABLE THAT A
BRIEF PERIOD OF FZRA MAY OCCUR EARLY THIS MORNING. REGIONAL RADAR
MOSAIC EARLY THIS MORNING SHOWS A SLUG OF PRECIP SLIDING EAST ACROSS
NORTH CENTRAL IL/FAR WESTERN IL...HOWEVER SFC OBS INDICATE THIS IS
VERY LIGHT AND IN SOME LOCATIONS NOT REACHING THE GROUND.
THE FOCUS TURNS TOWARDS WHAT WILL TRANSPIRE BY MID-MORNING
ACROSS THE CWFA. THE GREATEST FOCUS FOR P-TYPE CONCERNS CONTINUES TO
BE ALONG AND NORTH OF A ROCKFORD TO WAUKEGAN LINE. GUIDANCE HAS
STRUGGLED WITH THE ANALYSIS AND FORECAST FIELDS OF SFC TEMPS WITH A
COLD BIAS...THUS HAVE OPTED TO MAINTAIN A SLIGHTLY WARMER TREND.
SREF 2M TEMP PLUMES CONTINUE TO SHOW MINIMAL SPREAD WITH THE TEMPS
TDY...HOWEVER APPROXIMATELY 2-3 DEG TOO COOL. CONSIDERABLE
CORRECTIONS CONTINUE TO TAKE PLACE EVEN AT HOUR ZERO AHEAD OF THIS
SYSTEM...HOWEVER SOME CONSISTENCY HAS BEEN NOTED IN THE LACK OF AN
EASTERLY LLVL JET AT 850MB. THE U-WIND ANOMS HAVE CONTINUED TO BE
POSITIVE FROM THE SW AT 20-30KTS...INDICATING AN EFFICIENT TRANSPORT
OF PARCELS FROM SW TO NE. THE WAVE REMAINS OPEN...HOWEVER SHOULD
BEGIN TO AMPLIFY WITH TIME. THE PATH OF THE 850/925MB LOWS ARE
SIMILAR AMONGST THE EC/NAM IN TIME PUSHING FROM WEST TO EAST ACROSS
THE NORTHERN THIRD OF THE CWFA MIDDAY. JUST TO THE NORTH OF THIS
PATH APPEARS TO BE THE FAVORED REGION FOR P-TYPE CONCERNS AND
ACCUMULATING SNOW POTENTIAL. THE 540M THICKNESS LINE IS JUST NORTH
OF RFD...STRETCHING SLIGHTLY SOUTHEAST OF WAUKEGAN FOR MUCH OF THE
DAY.
AS MOISTURE CONTINUES TO FEED NORTHEAST AHEAD OF THE 500MB TROUGH
AXIS...AND PRECIP OVERSPREADS THE AREA...EXPECT DYNAMIC COOLING TO
SLOWLY OCCUR ACROSS THE FAR NORTHERN CWFA INTO SOUTHERN WISC. THIS
SHOULD ALLOW A SLOW TRANSITION OVER TO A RAIN/SNOW/SLEET MIX. AT
THIS TIME ACCUMS HAVE FOCUSED FURTHER NORTH ACROSS THE STATE LINE IN
SOUTHERN WISC. SREF PLUMES FOR RFD SUGGEST A 70% PROB OF FZRA/RA AT
ONSET TRENDING TO RA...THEN ARND 21-00Z 80% LIKELIHOOD OF SN.
FURTHER EAST AT UGN THE PROB OF SN IS SLIGHTLY HIGHER AND EARLIER.
THEN BY 00Z PRECIP TYPE SHUD SWITCH OVER TO ALL SN FROM WEST TO EAST
AS COOLER AIR STEADILY ADVECTS INTO THE CWFA. SOUNDINGS ARE NOT MUCH
ASSISTANCE AT THIS TIME...GIVEN THE POOR INITIALIZATION.
SNOW ACCUMS WILL ALSO BE A CHALLENGE...IF INDEED IT DOES SNOW AND
CAN ACCUMULATE. WITH THE HIGH DEW PTS HOVERING ARND THE FREEZING
MARK IT WILL BECOME A CHALLENGE. AT THIS TIME HAVE OPTED TO TRIM
BACK SNOW ACCUMS TO A 1-2" RANGE...WITH A FOCUS ACROSS MCHENRY/LAKE
COUNTIES. HOWEVER IF THE DYNAMIC COOLING CAN TAKE PLACE
EARLIER...AND THE FGEN BAND COULD CRANK OUT HIGHER ACCUMS. VERY
DIFFICULT TO PULL THE CURRENT ADVISORY...AND AT THE SAME TIME
DIFFICULT TO EXPAND THE ADVISORY FURTHER WEST. SO AT THIS TIME WILL
LEAVE HEADLINES AS IS.
CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL...LOW.
CONFIDENCE IN PRECIP CHANGE TIMING...LOW.
TONIGHT THROUGH FRIDAY...
500MB TROUGH AXIS PIVOTS OVERHEAD AND PUSHES NORTHEAST TOWARDS THE
EASTERN GREAT LAKES EARLY FRI. 850MB/SFC LOW CONTINUES TO DEVELOP
DOWNSTREAM OF OUR AREA...WITH A DRY WEDGE ADVERTISED BY GUIDANCE
ARRIVING ARND 06-09Z. THIS SHUD AID IN SHUTTING OFF THE
PRECIP...WHICH BY 00Z FRI SHUD BE ALMOST ALL LGT SNOW. SOME
WRAP-AROUND MOISTURE CONTINUES TO BE NOTED BY THE OPERATIONAL
SOLUTIONS...THUS HAVE CONTINUED MENTION OF SOME LIGHT SNOW OR
FLURRIES ACROSS ALONG THE BACKSIDE OF THE BETTER PRECIP SHIELD.
ANTI-CYCLONIC FLOW QUICKLY BUILDS IN FOR FRI...ERODING ANY REMAINING
LLVL MOISTURE. WINDS TURN NORTHEAST FOR A PERIOD FRI WHICH COULD
PULL SOME MOISTURE OFF OF LAKE MICHIGAN...ALTHOUGH THIS LOOKS VERY
MARGINAL. THUS HAVE CONTINUE WITH A DRY FORECAST. 850MB THERMAL
TROUGH REMAINS OVERHEAD AT -4 TO -6 DEG C FRI KEEPING AFTN MAX TEMPS
MAINLY IN THE LOW/MID 30S. THE FLOW REMAINS PROGRESSIVE WITH HEIGHTS
INCREASING UPSTREAM OF THE CWFA FRI AFTN/EVE. PRIOR TO THE MID-LVL
RIDGING ARRIVING...THE SFC RIDGE WILL BECOME CENTERED OVER THE CWFA
FRI NIGHT. THIS SHUD ALLOW SFC TEMPS TO RADIATE INTO THE TEENS/LOW
20S. LIGHT WINDS AND RECENT RAINFALL FROM THURSDAY COULD SET THE
STAGE FOR PATCHY FOG DEVELOPING FRI NIGHT.
CONFIDENCE...HIGH.
SATURDAY THROUGH WEDNESDAY...
500MB RIDGING PUSHES OVERHEAD FOR SAT/SUN AS A DEEP TROUGH CONTINUES
TO DIG INTO THE FOUR-CORNERS REGION. AS THIS UPSTREAM TROUGH BECOMES
AMPLIFIED...THE WESTERN GULF OF MEXICO WILL OPEN UP WITH ABUNDANT
MOISTURE STREAMING NORTH ACROSS THE OZARKS INTO THE WESTERN GREAT
LAKES SUN. GUIDANCE HAS CONTINUED TO INDICATE THAT AFTER A DRY
SAT...SUN WILL BE WET. THIS SYSTEM ON SUN APPEARS TO BE VERY ROBUST
BASED ON LATEST GUIDANCE...WITH MINIMAL SPREAD BEING NOTED AMONGST
THE ENSEMBLE MEMBERS. AT THIS TIME HAVE HELD OFF ON INCLUDING
CONVECTION IN THE FORECAST FOR SUN...WOULDN/T BE SURPRISED TO SEE
THIS ADDED OVER TIME. TEMPS SUN SURGE AHEAD OF THE SYSTEM...WITH
MID/UPR 40S LOOKING PROBABLE. COULD EVEN SEE TEMPS TOUCH 50 DEG IN A
FEW LOCATIONS OF OUR SOUTHERN CWFA.
THEN COOLER AIR WILL RETURN FOR THE START OF NEXT WEEK...WITH TEMPS
RETURNING TO SEASONAL CONDITIONS IN THE 30S.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* RAIN THROUGH MIDDAY...MIXING/CHANGING TO SNOW BY EVENING.
* SNOW EARLY EVENING DIMINISHING TO FLURRIES OR A FEW SNOW
SHOWERS LATE EVENING.
* LIGHT WINDS GRADUALLY BACKING FROM OUT OF THE SE TO E LATER
AFTERNOON AND EARLY EVENING...THEN TO OUT OF THE NE AND N LATE
EVENING AND INCREASING TO 10-15KT OVERNIGHT.
* CEILINGS LOWERING TO BELOW 010 BY EARLY EVENING THEN PERIODS OF
CEILINGS BELOW 007 WITH THE HEAVIER SNOWFALL DURING THE EARLY
EVENING.
* VISIBILITIES OF 1-2SM IN RA...SN...BR TIL LATER EVENING THEN
IMPROVING TO P6SM LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 18Z...
A NE TO SW ORIENTED UPPER TROUGH EXTENDS FROM WESTERN LAKE
SUPERIOR ACROSS IA TO N TX AT MIDDAY. MODELS HAVE IT PROGRESSING
TO EASTERN LAKE SUPERIOR...SE WI AND CENTRAL IL BY 08.06Z. IR
SATELLITE LOOP SHOWS A WELL DEFINED BAROCLINIC LEAF FROM LAKE MI
AND WI ACROSS TO EASTERN IA WITH TWO AREAS OF VERY COLD TOPS. ONE
WAS OVER E CENTRAL IA TO SE WI AND THE OTHER OVER W CENTRAL WI
TO FAR SE MN. THE COLD CLOUD TOPS WERE AHEAD OF A SHORT WAVE
CURRENTLY OVER IA AND LIFTING NE. THIS FEATURE IS EXPECTED TO
MOVE OVER THE KORD AND KMDW 22-23Z WITH THE UPPER TROUGH AXIS
CROSSING THE AREA MOVE OVER THE LOCAL AREA DURING THE EVENING.
ENHANCED LIFT IN THE MID LEVELS OUT AHEAD OF THE APPROACHING
SHORT WAVE AND THE UPPER TROUGH IS ENHANCING PRECIP PRODUCTION.
DYNAMIC COOLING OF THE LOWER LEVELS HAS CHANGED RAIN BACK TO SNOW
ACROSS FAR SOUTHERN WI AND FAR NE AND N CENTRAL IL. WITH THE AREA
OF GREATEST MID LEVEL ISENTROPIC LIFT AND FRONTOGENESIS SHIFTS
FURTHER E TO OVER NE IL DURING THE LATER AFTERNOON THE ENHANCED
PRECIPITATION AS WELL AS THE SWITCH-OVER TO SNOW IS EXPECTED TO
ALSO SHIFT E AND OVER THE LOCAL AREA THEN TAPER OFF TO SCATTERED
SNOW SHOWERS OR FLURRIES AFTER THE UPPER TROUGH MOVE E OF THE AREA
DURING THE EVENING.
A SURFACE LOW RELATED TO THIS SYSTEM WAS IN FAR SE IA AT MIDDAY
AND IS FORECAST TO MOVE E ACROSS CENTRAL IL DURING THE LATER
AFTERNOON...AND ACROSS NORTHERN IN DURING THE EVENING. IN RESPONSE
SURFACE WINDS WILL BACK FROM SE TO NE DURING THE AFTERNOON AND
BACK FURTHER TO OUT OF THE N DURING THE EVENING.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN PRECIP OCCURRENCE AND TYPE THROUGH
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS REST OF DAY AND THIS EVENING.
* MEDIUM CONFIDENCE IN TIMING OF CHANGE/MIX OF RAIN MID TO LATE
AFTERNOON AND TEN TO ALL SNOW BY EARLY EVENING.
* MEDIUM CONFIDENCE IS VIS TRENDS.
* LOW CONFIDENCE IN TIMING OR EXTENT OF LIFR CIGS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 16Z...
FRIDAY NIGHT...VFR. WX NIL.
SATURDAY...VFR. WX NIL.
SUNDAY...RAIN LIKELY. IFR CONDITIONS POSSIBLE.
MONDAY...CHANCE OF RAIN AND MVFR CIGS EARLY...THEN VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
117 PM CST
WINDS VARY ACROSS THE LAKE EARLY THIS AFTERNOON AS A TROUGH OF LOW
PRESSURE CONTINUES TO MOVE NORTHEAST ACROSS PORTIONS OF THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. THIS LOW WILL CONTINUE TO
LIFT NORTHEAST TOWARDS THE OHIO VALLEY TONIGHT WHILE A RIDGE OF
HIGH PRESSURE EXTENDING FROM ONTARIO EAST TO QUEBEC SLOWLY BUILDS
SOUTHEAST. AS THIS OCCURS...EXPECT THE PRESSURE GRADIENT TO
TIGHTEN WITH WINDS INCREASING INITIALLY OUT OF THE EAST BUT THEN
SHIFTING TO MORE OF A NORTHERLY WIND TONIGHT. THESE NORTHERLY
WINDS TO 30 KT WILL CONTINUE THROUGH MOST OF FRIDAY BEFORE SLOWLY
DIMINISHING AS THIS LOW EXITS TO THE EAST AND HIGH PRESSURE BUILDS
ACROSS THE LAKE. THEN EXPECT WINDS TO CONTINUE DIMINISHING INTO
FRIDAY NIGHT AND REMAINING ON THE LIGHTER SIDE SATURDAY BEFORE
PICKING UP OUT OF THE SOUTH THROUGH THE REMAINDER OF THE DAY
SATURDAY...REMAINING SOUTHERLY THROUGH THE REST OF THE WEEKEND.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006 UNTIL MIDNIGHT FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004 UNTIL 9 PM THURSDAY.
WINTER WEATHER ADVISORY...ILZ008-ILZ011-ILZ012-ILZ013-ILZ014
UNTIL 9 PM THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
148 PM CST THU FEB 7 2013
.MESOSCALE DISCUSSION...
106 PM CST
WE HAVE OPTED TO UPGRADE LAKE AND MCHENRY COUNTIES TO A WINTER
STORM WARNING. SHORT TERM GUIDANCE AND RADAR TRENDS CONTINUES TO
INDICATE HEAVY SNOW RATES IN ACROSS LAKE AND MCHENRY COUNTIES. WE
HAVE HAD REPORTS OF UP TO 2 INCHES IN BEACH PARK WITHIN A COUPLE
HOURS.
A RATHER IMPRESSIVE SHORT WAVE...CURRENTLY DIGGING SOUTHEAST ACROSS
EASTERN NEBRASKA AND INTO WESTERN IOWA...WILL LINK UP WITH A
STRENGTHENING BAND OF MID LEVEL FRONTOGENESIS AND NEGATIVE EPV TO
RESULT IN A BAND OF VERY HEAVY SNOW ACROSS NORTHEASTERN ILLINOIS
THROUGH THE AFTERNOON. THE RAIN SHOULD BEGIN TO QUICKLY TRANSITION
TO
SNOW ACROSS THE CHICAGO AREA...MAINLY ALONG AND NORTH OF THE
INTERSTATE 80 CORRIDOR BY MID AFTERNOON AS COLUMN COOL OCCURS IN
RESPONSE TO THE STRONG FRONTOGENETIC CIRCULATION. SOME OF THE LAST
AMDAR SOUNDINGS OUT OF ORD AND MDW...ONLY INDICATE A MAX TEMP OF
AROUND +1 AROUND 946 MB. SO IT WILL NOT TAKE MUCH TO TIP THE SCALES
IN FAVOR FOR SNOW. ONCE THE SNOW STARTS EXPECT HEAVY SNOW UP TO AN
INCH PER HOUR AT TIMES THROUGH THE EVENING COMMUTE. LESSER AMOUNTS
OF SNOW ARE EXPECTED FARTHER SOUTH TOWARDS THE I 80 CORRIDOR.
HOWEVER...IT MAY TAKE SOME TIME TO CHANGE OVER THIS FAR SOUTH...THUS
1 TO 3 INCHES ARE STILL POSSIBLE IN THIS AREA AS WELL INTO THE
EVENING.
SNOW AMOUNTS OF 2 TO 4 INCHES ARE LIKELY NORTH OF I-88 WITH 4 TO 8
INCHES LIKELY ACROSS LAKE AND MCHENRY COUNTIES.
KJB
&&
.DISCUSSION...
1117 AM CST
HAVE EXPANDED WINTER WEATHER ADVISORY TO INCLUDE WINNEBAGO AND BOONE
COUNTIES AND THE I-88 CORRIDOR.
RECENT AMDAR SOUNDINGS OUT OF ORD/MDW SHOW WARM LAYER UP TO JUST
UNDER +3C BETWEEN 950 AND 900 MB...WHICH LATEST RAP HAS A DECENT
HANDLE ON...RESULTING IN PLAIN RAIN FOR THE CITY AND POINTS SOUTH.
HOWEVER...TEMPERATURES AT THAT LEVEL ACROSS THE NORTHERN TIER OF
COUNTIES ARE DOWN BELOW 1C...ALREADY SUPPORTING A CHANGE TO SNOW
WITH THE CURRENT OB AT KUGN DOWN TO 1/2 MILE VSBY IN SNOW. ALSO
RECEIVED A REPORT OF SNOW STARTING TO ACCUMULATE IN WAUKEGAN AND
ZION IL AND A CHANGEOVER IN CHERRY VALLEY IL. WITH THIS IN
MIND...WILL START RIGHT OUT THE GATE WITH AN ADVISORY FOR WINNEBAGO
BOONE MCHENRY AND LAKE COUNTIES. ALSO BUMPED UP SNOW AMOUNTS TO 2 TO
5 INCHES FOR THE NORTHERN TIER GIVEN THE EARLIER START TIME TO THE
SNOW.
FARTHER TO THE SOUTH...FOR THE I-88 CORRIDOR...THE RAP ALSO SHOWS
THE 950 TO 900MB LAYER QUICKLY COOLING OFF BELOW 0C THROUGH THE
AFTERNOON INDICATIVE OF DYNAMIC COOLING. SO THESE AREAS SHOULD
CHANGE BACK OVER TO SNOW AND SEE DECENT SNOWFALL RATES GIVEN THE
FORCING AT HAND AND THE FACT THAT SURFACE TEMPERATURES EVEN NOW ARE
HOVERING JUST ABOVE FREEZING. FORECAST AMOUNTS WILL BE MARGINAL FOR
AN ADVISORY AT ROUGHLY 2 TO 4 INCHES...BUT SINCE THE RUSH HOUR WILL
BE IMPACTED...FELT IT WAS PRUDENT TO ISSUE ONE STARTING AT 20Z.
INCLUDED OGLE...DEKALB...KANE...DUPAGE AND COOK IN THIS NEW
ADVISORY...BUT KEEP IN MIND THAT THERE WILL LIKELY BE A GRADIENT
FROM NORTH TO SOUTH ACROSS DEKALB THROUGH COOK WHERE THE NORTHERN
PORTIONS WILL BE SEEING THE MORE SIGNIFICANT IMPACTS FROM THE SNOW.
WITH A GOOD FGEN BAND COINCIDENT WITH STRONG LIFT NOTED ON MUCH OF
THE GUIDANCE PIVOTING ACROSS THE CWA AND BEING LOCATED OVER
NORTHEAST ILLINOIS INCLUDING CHICAGO BY THE EARLY EVENING...ALSO
CONCERNED THAT HEAVY SNOWFALL RATES COULD LEAD TO HIGHER TOTALS THAN
THE 3 TO 5 INDICATED IN LAKE AND MCHENRY ALONG THE I-88 CORRIDOR IN
NORTHEAST ILLINOIS. WILL CONTINUE TO ASSESS FOR ANY FURTHER UPDATES
NEEDED. BUT IN SUM...THE AFTERNOON COMMUTE IS LIKELY TO BE PRETTY
MESSY...ESPECIALLY FOR THE NORTHERN PART OF THE METRO.
RC/KJB
//PREV DISCUSSION...
553 AM CST
PRECIPITATION HAS OVERSPREAD NORTHERN IL EARLY THIS MORNING WITH
TEMPERATURES INITIALLY ABOVE FREEZING. AS PRECIPITATION BECAME A
LITTLE STEADIER...TEMPERATURES HAVE FALLEN TO OR A DEGREE BELOW
FREEZING. THIS HAS RESULTED IN FREEZING RAIN BEING REPORTED ACROSS
MANY OF MY FAR NORTHEAST ILLINOIS AREAS...MAINLY ALONG AND NORTH
OF I-88. THUS HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY UNTIL
10 AM...WHICH IS THE TIME THAT TEMPS SHOULD PUSH ABOVE THE
FREEZING POINT WITH RISING DEW POINTS. PRECIPITATION AT THAT POINT
SHOULD TRANSITION OVER TO ALL RAIN.
BEACHLER
//PREV DISCUSSION...
337 AM CST
VERY DYNAMIC AND CHALLENGING WEATHER SYSTEM CONTINUES TO SLIDE EAST
FROM THE CENTRAL PLAINS TODAY. SFC TEMPS HAVE REMAINED MILD
OVERNIGHT IN THE LOW/MID 30S...WITH DEW POINTS HOVERING AROUND 30
DEG IN MANY LOCATIONS. IR IMAGERY INDICATES CONSIDERABLE CLOUD
COVER...WITH THE COLDEST CLOUDS ORIENTED FROM CENTRAL IOWA NORTHEAST
THROUGH CENTRAL WISCONSIN INTO NORTHERN LOWER MICHIGAN. EARLY THIS
MORNING CONSIDERABLE LIGHTING WAS NOTED ACROSS KANSAS AND CENTRAL
MISSOURI...INDICATING THAT CONSIDERABLE LIFT/UPGLIDE WAS OCCURRING
IN THIS AREA. IN ADDITION TO THE THUNDERSTORM ACTIVITY UPSTREAM OF
NORTHERN IL/NORTHWEST IN...WAS TEMPS IN THE LOW/MID 40S ACROSS
SOUTH CENTRAL IOWA EARLY THIS MORNING. WARM/MOIST AIR CONTINUES TO
BE
TRANSPORTED NORTH FROM THE WESTERN GULF OF MEXICO AHEAD OF THE
SHORTWAVE...WHICH WILL PLAY A LARGE ROLE IN KEEPING THE BULK OF THE
PRECIP AT THE ONSET AS LIQUID. HOWEVER...A FEW SITES CONTINUE TO
SHOW TEMPS AROUND THE FREEZING MARK. THUS IT IS CONCEIVABLE THAT A
BRIEF PERIOD OF FZRA MAY OCCUR EARLY THIS MORNING. REGIONAL RADAR
MOSAIC EARLY THIS MORNING SHOWS A SLUG OF PRECIP SLIDING EAST ACROSS
NORTH CENTRAL IL/FAR WESTERN IL...HOWEVER SFC OBS INDICATE THIS IS
VERY LIGHT AND IN SOME LOCATIONS NOT REACHING THE GROUND.
THE FOCUS TURNS TOWARDS WHAT WILL TRANSPIRE BY MID-MORNING
ACROSS THE CWFA. THE GREATEST FOCUS FOR P-TYPE CONCERNS CONTINUES TO
BE ALONG AND NORTH OF A ROCKFORD TO WAUKEGAN LINE. GUIDANCE HAS
STRUGGLED WITH THE ANALYSIS AND FORECAST FIELDS OF SFC TEMPS WITH A
COLD BIAS...THUS HAVE OPTED TO MAINTAIN A SLIGHTLY WARMER TREND.
SREF 2M TEMP PLUMES CONTINUE TO SHOW MINIMAL SPREAD WITH THE TEMPS
TDY...HOWEVER APPROXIMATELY 2-3 DEG TOO COOL. CONSIDERABLE
CORRECTIONS CONTINUE TO TAKE PLACE EVEN AT HOUR ZERO AHEAD OF THIS
SYSTEM...HOWEVER SOME CONSISTENCY HAS BEEN NOTED IN THE LACK OF AN
EASTERLY LLVL JET AT 850MB. THE U-WIND ANOMS HAVE CONTINUED TO BE
POSITIVE FROM THE SW AT 20-30KTS...INDICATING AN EFFICIENT TRANSPORT
OF PARCELS FROM SW TO NE. THE WAVE REMAINS OPEN...HOWEVER SHOULD
BEGIN TO AMPLIFY WITH TIME. THE PATH OF THE 850/925MB LOWS ARE
SIMILAR AMONGST THE EC/NAM IN TIME PUSHING FROM WEST TO EAST ACROSS
THE NORTHERN THIRD OF THE CWFA MIDDAY. JUST TO THE NORTH OF THIS
PATH APPEARS TO BE THE FAVORED REGION FOR P-TYPE CONCERNS AND
ACCUMULATING SNOW POTENTIAL. THE 540M THICKNESS LINE IS JUST NORTH
OF RFD...STRETCHING SLIGHTLY SOUTHEAST OF WAUKEGAN FOR MUCH OF THE
DAY.
AS MOISTURE CONTINUES TO FEED NORTHEAST AHEAD OF THE 500MB TROUGH
AXIS...AND PRECIP OVERSPREADS THE AREA...EXPECT DYNAMIC COOLING TO
SLOWLY OCCUR ACROSS THE FAR NORTHERN CWFA INTO SOUTHERN WISC. THIS
SHOULD ALLOW A SLOW TRANSITION OVER TO A RAIN/SNOW/SLEET MIX. AT
THIS TIME ACCUMS HAVE FOCUSED FURTHER NORTH ACROSS THE STATE LINE IN
SOUTHERN WISC. SREF PLUMES FOR RFD SUGGEST A 70% PROB OF FZRA/RA AT
ONSET TRENDING TO RA...THEN ARND 21-00Z 80% LIKELIHOOD OF SN.
FURTHER EAST AT UGN THE PROB OF SN IS SLIGHTLY HIGHER AND EARLIER.
THEN BY 00Z PRECIP TYPE SHUD SWITCH OVER TO ALL SN FROM WEST TO EAST
AS COOLER AIR STEADILY ADVECTS INTO THE CWFA. SOUNDINGS ARE NOT MUCH
ASSISTANCE AT THIS TIME...GIVEN THE POOR INITIALIZATION.
SNOW ACCUMS WILL ALSO BE A CHALLENGE...IF INDEED IT DOES SNOW AND
CAN ACCUMULATE. WITH THE HIGH DEW PTS HOVERING ARND THE FREEZING
MARK IT WILL BECOME A CHALLENGE. AT THIS TIME HAVE OPTED TO TRIM
BACK SNOW ACCUMS TO A 1-2" RANGE...WITH A FOCUS ACROSS MCHENRY/LAKE
COUNTIES. HOWEVER IF THE DYNAMIC COOLING CAN TAKE PLACE
EARLIER...AND THE FGEN BAND COULD CRANK OUT HIGHER ACCUMS. VERY
DIFFICULT TO PULL THE CURRENT ADVISORY...AND AT THE SAME TIME
DIFFICULT TO EXPAND THE ADVISORY FURTHER WEST. SO AT THIS TIME WILL
LEAVE HEADLINES AS IS.
CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL...LOW.
CONFIDENCE IN PRECIP CHANGE TIMING...LOW.
TONIGHT THROUGH FRIDAY...
500MB TROUGH AXIS PIVOTS OVERHEAD AND PUSHES NORTHEAST TOWARDS THE
EASTERN GREAT LAKES EARLY FRI. 850MB/SFC LOW CONTINUES TO DEVELOP
DOWNSTREAM OF OUR AREA...WITH A DRY WEDGE ADVERTISED BY GUIDANCE
ARRIVING ARND 06-09Z. THIS SHUD AID IN SHUTTING OFF THE
PRECIP...WHICH BY 00Z FRI SHUD BE ALMOST ALL LGT SNOW. SOME
WRAP-AROUND MOISTURE CONTINUES TO BE NOTED BY THE OPERATIONAL
SOLUTIONS...THUS HAVE CONTINUED MENTION OF SOME LIGHT SNOW OR
FLURRIES ACROSS ALONG THE BACKSIDE OF THE BETTER PRECIP SHIELD.
ANTI-CYCLONIC FLOW QUICKLY BUILDS IN FOR FRI...ERODING ANY REMAINING
LLVL MOISTURE. WINDS TURN NORTHEAST FOR A PERIOD FRI WHICH COULD
PULL SOME MOISTURE OFF OF LAKE MICHIGAN...ALTHOUGH THIS LOOKS VERY
MARGINAL. THUS HAVE CONTINUE WITH A DRY FORECAST. 850MB THERMAL
TROUGH REMAINS OVERHEAD AT -4 TO -6 DEG C FRI KEEPING AFTN MAX TEMPS
MAINLY IN THE LOW/MID 30S. THE FLOW REMAINS PROGRESSIVE WITH HEIGHTS
INCREASING UPSTREAM OF THE CWFA FRI AFTN/EVE. PRIOR TO THE MID-LVL
RIDGING ARRIVING...THE SFC RIDGE WILL BECOME CENTERED OVER THE CWFA
FRI NIGHT. THIS SHUD ALLOW SFC TEMPS TO RADIATE INTO THE TEENS/LOW
20S. LIGHT WINDS AND RECENT RAINFALL FROM THURSDAY COULD SET THE
STAGE FOR PATCHY FOG DEVELOPING FRI NIGHT.
CONFIDENCE...HIGH.
SATURDAY THROUGH WEDNESDAY...
500MB RIDGING PUSHES OVERHEAD FOR SAT/SUN AS A DEEP TROUGH CONTINUES
TO DIG INTO THE FOUR-CORNERS REGION. AS THIS UPSTREAM TROUGH BECOMES
AMPLIFIED...THE WESTERN GULF OF MEXICO WILL OPEN UP WITH ABUNDANT
MOISTURE STREAMING NORTH ACROSS THE OZARKS INTO THE WESTERN GREAT
LAKES SUN. GUIDANCE HAS CONTINUED TO INDICATE THAT AFTER A DRY
SAT...SUN WILL BE WET. THIS SYSTEM ON SUN APPEARS TO BE VERY ROBUST
BASED ON LATEST GUIDANCE...WITH MINIMAL SPREAD BEING NOTED AMONGST
THE ENSEMBLE MEMBERS. AT THIS TIME HAVE HELD OFF ON INCLUDING
CONVECTION IN THE FORECAST FOR SUN...WOULDN/T BE SURPRISED TO SEE
THIS ADDED OVER TIME. TEMPS SUN SURGE AHEAD OF THE SYSTEM...WITH
MID/UPR 40S LOOKING PROBABLE. COULD EVEN SEE TEMPS TOUCH 50 DEG IN A
FEW LOCATIONS OF OUR SOUTHERN CWFA.
THEN COOLER AIR WILL RETURN FOR THE START OF NEXT WEEK...WITH TEMPS
RETURNING TO SEASONAL CONDITIONS IN THE 30S.
CONFIDENCE...HIGH.
BEACHLER
&&
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RAIN THROUGH MIDDAY...MIXING/CHANGING TO SNOW BY EVENING.
* SNOW EARLY EVENING DIMINISHING TO FLURRIES OR A FEW SNOW
SHOWERS LATE EVENING.
* LIGHT WINDS GRADUALLY BACKING FROM OUT OF THE SE TO E LATER
AFTERNOON AND EARLY EVENING...THEN TO OUT OF THE NE AND N LATE
EVENING AND INCREASING TO 10-15KT OVERNIGHT.
* CEILINGS LOWERING TO BELOW 010 BY EARLY EVENING THEN PERIODS OF
CEILINGS BELOW 007 WITH THE HEAVIER SNOWFALL DURING THE EARLY
EVENING.
* VISIBILTIES OF 1-2SM IN RA...SN...BR TIL LATER EVENING THEN
IMPROVING TO P6SM LATE TONIGHT.
TRS
//DISCUSSION...UPDATED 18Z...
A NE TO SW ORIENTED UPPER TROUGH EXTENDS FROM WESTERN LAKE
SUPERIOR ACROSS IA TO N TX AT MIDDAY. MODELS HAVE IT PROGESSING
TO EASTERN LAKE SUPERIOR...SE WI AND CENTRAL IL BY 08.06Z. IR
SATELLITE LOOP SHOWS A WELL DEFINED BAROCLYNIC LEAF FROM LAKE MI
AND WI ACROSS TO EASTERN IA WITH TWO AREAS OF VERY COLD TOPS. ONE
WAS OVER E CENTRAL IA TO TOSE WI AND THE OTHER OVER W CENTRAL WI
TO FAR SE MN. THE COLD CLOUD TOPS WERE AHEAD OF A SHORT WAVE
CURRENTLY OVER IA AND LIFTING NE. THIS FEATURE IS EXPECTED TO
MOVE OVER THE KORD AND KMDW 22-23Z WITH THE UPPER TROUGH AXIS
CORSSING THE AREA MOVE OVER THE LOCAL AREA DURING THE EVENING.
ENHANCED LIFT IN THE MID LEVELS OUT AHEAD OF THE APPROACHING
SHORT WAVE AND THE UPPER TROUGH IS ENHANCING PRECIP PRODUCTION.
DYNAMIC COOLING OF THE LOWER LEVELS HAS CHANGED RAIN BACK TO SNOW
ACROSS FAR SOUTHERN WI AND FAR NE AND N CENTRAL IL. WITH THE AREA
OF GREATEST MID LEVEL ISENTROPIC LIFT AND FRONTOGENESIS SHIFTS
FUTHER E TO OVER NE IL DURING THE LATER AFTERNOON THE ENHANCED
PRECIPITATION AS WELL AS THE SWITCH-OVER TO SNOW IS EXPECTED TO
ALSO SHIFT E AND OVER THE LOCAL AREA THEN TAPER OFF TO SCATTERED
SNOW SHOWERS OR FLURRIES AFTER THE UPPER TROUGH MOVE E OF THE AREA
DURING THE EVENING.
A SURFACE LOW RELATED TO THIS SYSTEM WAS IN FAR SE IA AT MIDDAY
AND IS FORECAST TO MOVE E ACROSS CENTRAL IL DURING THE LATER
AFTERNOON...AND ACROSS NORTHERN IN DURIN THE EVENING. IN RESPONSE
SURFACE WINDS WILL BACK FROM SE TO NE DURING THE AFRTERNOON AND
BACK FURTHER TO OUT OF THE N DURING THE EVENING.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN PRECIP OCCURRENCE AND TYPE THROUGH
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS REST OF DAY AND THIS EVENING.
* MEDIUM CONFIDENCE IN TIMING OF CHANGE/MIX OF RAIN MID TO LATE
AFTERNOON AND TEN TO ALL SNOW BY EARLY EVENING.
* MEDIUM CONFIDENCE IS VIS TRENDS.
* LOW CONFIDENCE IN TIMING OR EXTENT OF LIFR CIGS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 16Z...
FRIDAY NIGHT...VFR. WX NIL.
SATURDAY...VFR. WX NIL.
SUNDAY...RAIN LIKELY. IFR CONDITIONS POSSIBLE.
MONDAY...CHANCE OF RAIN AND MVFR CIGS EARLY...THEN VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
117 PM CST
WINDS VARY ACROSS THE LAKE EARLY THIS AFTERNOON AS A TROUGH OF LOW
PRESSURE CONTINUES TO MOVE NORTHEAST ACROSS PORTIONS OF THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. THIS LOW WILL CONTINUE TO
LIFT NORTHEAST TOWARDS THE OHIO VALLEY TONIGHT WHILE A RIDGE OF
HIGH PRESSURE EXTENDING FROM ONTARIO EAST TO QUEBEC SLOWLY BUILDS
SOUTHEAST. AS THIS OCCURS...EXPECT THE PRESSURE GRADIENT TO
TIGHTEN WITH WINDS INCREASING INITIALLY OUT OF THE EAST BUT THEN
SHIFTING TO MORE OF A NORTHERLY WIND TONIGHT. THESE NORTHERLY
WINDS TO 30 KT WILL CONTINUE THROUGH MOST OF FRIDAY BEFORE SLOWLY
DIMINISHING AS THIS LOW EXITS TO THE EAST AND HIGH PRESSURE BUILDS
ACROSS THE LAKE. THEN EXPECT WINDS TO CONTINUE DIMINISHING INTO
FRIDAY NIGHT AND REMAINING ON THE LIGHTER SIDE SATURDAY BEFORE
PICKING UP OUT OF THE SOUTH THROUGH THE REMAINDER OF THE DAY
SATURDAY...REMAINING SOUTHERLY THROUGH THE REST OF THE WEEKEND.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006 UNTIL MIDNIGHT FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004 UNTIL 9 PM THURSDAY.
WINTER WEATHER ADVISORY...ILZ008-ILZ011-ILZ012-ILZ013-ILZ014
UNTIL 9 PM THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
118 PM CST THU FEB 7 2013
.MESOSCALE DISCUSSION...
106 PM CST
WE HAVE OPTED TO UPGRADE LAKE AND MCHENRY COUNTIES TO A WINTER
STORM WARNING. SHORT TERM GUIDANCE AND RADAR TRENDS CONTINUES TO
INDICATE HEAVY SNOW RATES IN ACROSS LAKE AND MCHENRY COUNTIES. WE
HAVE HAD REPORTS OF UP TO 2 INCHES IN BEACH PARK WITHIN A COUPLE
HOURS.
A RATHER IMPRESSIVE SHORT WAVE...CURRENTLY DIGGING SOUTHEAST ACROSS
EASTERN NEBRASKA AND INTO WESTERN IOWA...WILL LINK UP WITH A
STRENGTHENING BAND OF MID LEVEL FRONTOGENESIS AND NEGATIVE EPV TO
RESULT IN A BAND OF VERY HEAVY SNOW ACROSS NORTHEASTERN ILLINOIS
THROUGH THE AFTERNOON. THE RAIN SHOULD BEGIN TO QUICKLY TRANSITION TO
SNOW ACROSS THE CHICAGO AREA...MAINLY ALONG AND NORTH OF THE
INTERSTATE 80 CORRIDOR BY MID AFTERNOON AS COLUMN COOL OCCURS IN
RESPONSE TO THE STRONG FRONTOGENETIC CIRCULATION. SOME OF THE LAST
AMDAR SOUNDINGS OUT OF ORD AND MDW...ONLY INDICATE A MAX TEMP OF
AROUND +1 AROUND 946 MB. SO IT WILL NOT TAKE MUCH TO TIP THE SCALES
IN FAVOR FOR SNOW. ONCE THE SNOW STARTS EXPECT HEAVY SNOW UP TO AN
INCH PER HOUR AT TIMES THROUGH THE EVENING COMMUTE. LESSER AMOUNTS
OF SNOW ARE EXPECTED FARTHER SOUTH TOWARDS THE I 80 CORRIDOR.
HOWEVER...IT MAY TAKE SOME TIME TO CHANGE OVER THIS FAR SOUTH...THUS
1 TO 3 INCHES ARE STILL POSSIBLE IN THIS AREA AS WELL INTO THE
EVENING.
SNOW AMOUNTS OF 2 TO 4 INCHES ARE LIKELY NORTH OF I-88 WITH 4 TO 8
INCHES LIKELY ACROSS LAKE AND MCHENRY COUNTIES.
KJB
&&
.DISCUSSION...
1117 AM CST
HAVE EXPANDED WINTER WEATHER ADVISORY TO INCLUDE WINNEBAGO AND BOONE
COUNTIES AND THE I-88 CORRIDOR.
RECENT AMDAR SOUNDINGS OUT OF ORD/MDW SHOW WARM LAYER UP TO JUST
UNDER +3C BETWEEN 950 AND 900 MB...WHICH LATEST RAP HAS A DECENT
HANDLE ON...RESULTING IN PLAIN RAIN FOR THE CITY AND POINTS SOUTH.
HOWEVER...TEMPERATURES AT THAT LEVEL ACROSS THE NORTHERN TIER OF
COUNTIES ARE DOWN BELOW 1C...ALREADY SUPPORTING A CHANGE TO SNOW
WITH THE CURRENT OB AT KUGN DOWN TO 1/2 MILE VSBY IN SNOW. ALSO
RECEIVED A REPORT OF SNOW STARTING TO ACCUMULATE IN WAUKEGAN AND
ZION IL AND A CHANGEOVER IN CHERRY VALLEY IL. WITH THIS IN
MIND...WILL START RIGHT OUT THE GATE WITH AN ADVISORY FOR WINNEBAGO
BOONE MCHENRY AND LAKE COUNTIES. ALSO BUMPED UP SNOW AMOUNTS TO 2 TO
5 INCHES FOR THE NORTHERN TIER GIVEN THE EARLIER START TIME TO THE
SNOW.
FARTHER TO THE SOUTH...FOR THE I-88 CORRIDOR...THE RAP ALSO SHOWS
THE 950 TO 900MB LAYER QUICKLY COOLING OFF BELOW 0C THROUGH THE
AFTERNOON INDICATIVE OF DYNAMIC COOLING. SO THESE AREAS SHOULD
CHANGE BACK OVER TO SNOW AND SEE DECENT SNOWFALL RATES GIVEN THE
FORCING AT HAND AND THE FACT THAT SURFACE TEMPERATURES EVEN NOW ARE
HOVERING JUST ABOVE FREEZING. FORECAST AMOUNTS WILL BE MARGINAL FOR
AN ADVISORY AT ROUGHLY 2 TO 4 INCHES...BUT SINCE THE RUSH HOUR WILL
BE IMPACTED...FELT IT WAS PRUDENT TO ISSUE ONE STARTING AT 20Z.
INCLUDED OGLE...DEKALB...KANE...DUPAGE AND COOK IN THIS NEW
ADVISORY...BUT KEEP IN MIND THAT THERE WILL LIKELY BE A GRADIENT
FROM NORTH TO SOUTH ACROSS DEKALB THROUGH COOK WHERE THE NORTHERN
PORTIONS WILL BE SEEING THE MORE SIGNIFICANT IMPACTS FROM THE SNOW.
WITH A GOOD FGEN BAND COINCIDENT WITH STRONG LIFT NOTED ON MUCH OF
THE GUIDANCE PIVOTING ACROSS THE CWA AND BEING LOCATED OVER
NORTHEAST ILLINOIS INCLUDING CHICAGO BY THE EARLY EVENING...ALSO
CONCERNED THAT HEAVY SNOWFALL RATES COULD LEAD TO HIGHER TOTALS THAN
THE 3 TO 5 INDICATED IN LAKE AND MCHENRY ALONG THE I-88 CORRIDOR IN
NORTHEAST ILLINOIS. WILL CONTINUE TO ASSESS FOR ANY FURTHER UPDATES
NEEDED. BUT IN SUM...THE AFTERNOON COMMUTE IS LIKELY TO BE PRETTY
MESSY...ESPECIALLY FOR THE NORTHERN PART OF THE METRO.
RC/KJB
//PREV DISCUSSION...
553 AM CST
PRECIPITATION HAS OVERSPREAD NORTHERN IL EARLY THIS MORNING WITH
TEMPERATURES INITIALLY ABOVE FREEZING. AS PRECIPITATION BECAME A
LITTLE STEADIER...TEMPERATURES HAVE FALLEN TO OR A DEGREE BELOW
FREEZING. THIS HAS RESULTED IN FREEZING RAIN BEING REPORTED ACROSS
MANY OF MY FAR NORTHEAST ILLINOIS AREAS...MAINLY ALONG AND NORTH
OF I-88. THUS HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY UNTIL
10 AM...WHICH IS THE TIME THAT TEMPS SHOULD PUSH ABOVE THE
FREEZING POINT WITH RISING DEW POINTS. PRECIPITATION AT THAT POINT
SHOULD TRANSITION OVER TO ALL RAIN.
BEACHLER
//PREV DISCUSSION...
337 AM CST
VERY DYNAMIC AND CHALLENGING WEATHER SYSTEM CONTINUES TO SLIDE EAST
FROM THE CENTRAL PLAINS TODAY. SFC TEMPS HAVE REMAINED MILD
OVERNIGHT IN THE LOW/MID 30S...WITH DEW POINTS HOVERING AROUND 30
DEG IN MANY LOCATIONS. IR IMAGERY INDICATES CONSIDERABLE CLOUD
COVER...WITH THE COLDEST CLOUDS ORIENTED FROM CENTRAL IOWA NORTHEAST
THROUGH CENTRAL WISCONSIN INTO NORTHERN LOWER MICHIGAN. EARLY THIS
MORNING CONSIDERABLE LIGHTING WAS NOTED ACROSS KANSAS AND CENTRAL
MISSOURI...INDICATING THAT CONSIDERABLE LIFT/UPGLIDE WAS OCCURRING
IN THIS AREA. IN ADDITION TO THE THUNDERSTORM ACTIVITY UPSTREAM OF
NORTHERN IL/NORTHWEST IN...WAS TEMPS IN THE LOW/MID 40S ACROSS
SOUTH CENTRAL IOWA EARLY THIS MORNING. WARM/MOIST AIR CONTINUES TO BE
TRANSPORTED NORTH FROM THE WESTERN GULF OF MEXICO AHEAD OF THE
SHORTWAVE...WHICH WILL PLAY A LARGE ROLE IN KEEPING THE BULK OF THE
PRECIP AT THE ONSET AS LIQUID. HOWEVER...A FEW SITES CONTINUE TO
SHOW TEMPS AROUND THE FREEZING MARK. THUS IT IS CONCEIVABLE THAT A
BRIEF PERIOD OF FZRA MAY OCCUR EARLY THIS MORNING. REGIONAL RADAR
MOSAIC EARLY THIS MORNING SHOWS A SLUG OF PRECIP SLIDING EAST ACROSS
NORTH CENTRAL IL/FAR WESTERN IL...HOWEVER SFC OBS INDICATE THIS IS
VERY LIGHT AND IN SOME LOCATIONS NOT REACHING THE GROUND.
THE FOCUS TURNS TOWARDS WHAT WILL TRANSPIRE BY MID-MORNING
ACROSS THE CWFA. THE GREATEST FOCUS FOR P-TYPE CONCERNS CONTINUES TO
BE ALONG AND NORTH OF A ROCKFORD TO WAUKEGAN LINE. GUIDANCE HAS
STRUGGLED WITH THE ANALYSIS AND FORECAST FIELDS OF SFC TEMPS WITH A
COLD BIAS...THUS HAVE OPTED TO MAINTAIN A SLIGHTLY WARMER TREND.
SREF 2M TEMP PLUMES CONTINUE TO SHOW MINIMAL SPREAD WITH THE TEMPS
TDY...HOWEVER APPROXIMATELY 2-3 DEG TOO COOL. CONSIDERABLE
CORRECTIONS CONTINUE TO TAKE PLACE EVEN AT HOUR ZERO AHEAD OF THIS
SYSTEM...HOWEVER SOME CONSISTENCY HAS BEEN NOTED IN THE LACK OF AN
EASTERLY LLVL JET AT 850MB. THE U-WIND ANOMS HAVE CONTINUED TO BE
POSITIVE FROM THE SW AT 20-30KTS...INDICATING AN EFFICIENT TRANSPORT
OF PARCELS FROM SW TO NE. THE WAVE REMAINS OPEN...HOWEVER SHOULD
BEGIN TO AMPLIFY WITH TIME. THE PATH OF THE 850/925MB LOWS ARE
SIMILAR AMONGST THE EC/NAM IN TIME PUSHING FROM WEST TO EAST ACROSS
THE NORTHERN THIRD OF THE CWFA MIDDAY. JUST TO THE NORTH OF THIS
PATH APPEARS TO BE THE FAVORED REGION FOR P-TYPE CONCERNS AND
ACCUMULATING SNOW POTENTIAL. THE 540M THICKNESS LINE IS JUST NORTH
OF RFD...STRETCHING SLIGHTLY SOUTHEAST OF WAUKEGAN FOR MUCH OF THE
DAY.
AS MOISTURE CONTINUES TO FEED NORTHEAST AHEAD OF THE 500MB TROUGH
AXIS...AND PRECIP OVERSPREADS THE AREA...EXPECT DYNAMIC COOLING TO
SLOWLY OCCUR ACROSS THE FAR NORTHERN CWFA INTO SOUTHERN WISC. THIS
SHOULD ALLOW A SLOW TRANSITION OVER TO A RAIN/SNOW/SLEET MIX. AT
THIS TIME ACCUMS HAVE FOCUSED FURTHER NORTH ACROSS THE STATE LINE IN
SOUTHERN WISC. SREF PLUMES FOR RFD SUGGEST A 70% PROB OF FZRA/RA AT
ONSET TRENDING TO RA...THEN ARND 21-00Z 80% LIKELIHOOD OF SN.
FURTHER EAST AT UGN THE PROB OF SN IS SLIGHTLY HIGHER AND EARLIER.
THEN BY 00Z PRECIP TYPE SHUD SWITCH OVER TO ALL SN FROM WEST TO EAST
AS COOLER AIR STEADILY ADVECTS INTO THE CWFA. SOUNDINGS ARE NOT MUCH
ASSISTANCE AT THIS TIME...GIVEN THE POOR INITIALIZATION.
SNOW ACCUMS WILL ALSO BE A CHALLENGE...IF INDEED IT DOES SNOW AND
CAN ACCUMULATE. WITH THE HIGH DEW PTS HOVERING ARND THE FREEZING
MARK IT WILL BECOME A CHALLENGE. AT THIS TIME HAVE OPTED TO TRIM
BACK SNOW ACCUMS TO A 1-2" RANGE...WITH A FOCUS ACROSS MCHENRY/LAKE
COUNTIES. HOWEVER IF THE DYNAMIC COOLING CAN TAKE PLACE
EARLIER...AND THE FGEN BAND COULD CRANK OUT HIGHER ACCUMS. VERY
DIFFICULT TO PULL THE CURRENT ADVISORY...AND AT THE SAME TIME
DIFFICULT TO EXPAND THE ADVISORY FURTHER WEST. SO AT THIS TIME WILL
LEAVE HEADLINES AS IS.
CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL...LOW.
CONFIDENCE IN PRECIP CHANGE TIMING...LOW.
TONIGHT THROUGH FRIDAY...
500MB TROUGH AXIS PIVOTS OVERHEAD AND PUSHES NORTHEAST TOWARDS THE
EASTERN GREAT LAKES EARLY FRI. 850MB/SFC LOW CONTINUES TO DEVELOP
DOWNSTREAM OF OUR AREA...WITH A DRY WEDGE ADVERTISED BY GUIDANCE
ARRIVING ARND 06-09Z. THIS SHUD AID IN SHUTTING OFF THE
PRECIP...WHICH BY 00Z FRI SHUD BE ALMOST ALL LGT SNOW. SOME
WRAP-AROUND MOISTURE CONTINUES TO BE NOTED BY THE OPERATIONAL
SOLUTIONS...THUS HAVE CONTINUED MENTION OF SOME LIGHT SNOW OR
FLURRIES ACROSS ALONG THE BACKSIDE OF THE BETTER PRECIP SHIELD.
ANTI-CYCLONIC FLOW QUICKLY BUILDS IN FOR FRI...ERODING ANY REMAINING
LLVL MOISTURE. WINDS TURN NORTHEAST FOR A PERIOD FRI WHICH COULD
PULL SOME MOISTURE OFF OF LAKE MICHIGAN...ALTHOUGH THIS LOOKS VERY
MARGINAL. THUS HAVE CONTINUE WITH A DRY FORECAST. 850MB THERMAL
TROUGH REMAINS OVERHEAD AT -4 TO -6 DEG C FRI KEEPING AFTN MAX TEMPS
MAINLY IN THE LOW/MID 30S. THE FLOW REMAINS PROGRESSIVE WITH HEIGHTS
INCREASING UPSTREAM OF THE CWFA FRI AFTN/EVE. PRIOR TO THE MID-LVL
RIDGING ARRIVING...THE SFC RIDGE WILL BECOME CENTERED OVER THE CWFA
FRI NIGHT. THIS SHUD ALLOW SFC TEMPS TO RADIATE INTO THE TEENS/LOW
20S. LIGHT WINDS AND RECENT RAINFALL FROM THURSDAY COULD SET THE
STAGE FOR PATCHY FOG DEVELOPING FRI NIGHT.
CONFIDENCE...HIGH.
SATURDAY THROUGH WEDNESDAY...
500MB RIDGING PUSHES OVERHEAD FOR SAT/SUN AS A DEEP TROUGH CONTINUES
TO DIG INTO THE FOUR-CORNERS REGION. AS THIS UPSTREAM TROUGH BECOMES
AMPLIFIED...THE WESTERN GULF OF MEXICO WILL OPEN UP WITH ABUNDANT
MOISTURE STREAMING NORTH ACROSS THE OZARKS INTO THE WESTERN GREAT
LAKES SUN. GUIDANCE HAS CONTINUED TO INDICATE THAT AFTER A DRY
SAT...SUN WILL BE WET. THIS SYSTEM ON SUN APPEARS TO BE VERY ROBUST
BASED ON LATEST GUIDANCE...WITH MINIMAL SPREAD BEING NOTED AMONGST
THE ENSEMBLE MEMBERS. AT THIS TIME HAVE HELD OFF ON INCLUDING
CONVECTION IN THE FORECAST FOR SUN...WOULDN/T BE SURPRISED TO SEE
THIS ADDED OVER TIME. TEMPS SUN SURGE AHEAD OF THE SYSTEM...WITH
MID/UPR 40S LOOKING PROBABLE. COULD EVEN SEE TEMPS TOUCH 50 DEG IN A
FEW LOCATIONS OF OUR SOUTHERN CWFA.
THEN COOLER AIR WILL RETURN FOR THE START OF NEXT WEEK...WITH TEMPS
RETURNING TO SEASONAL CONDITIONS IN THE 30S.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* RAIN THROUGH THE REST OF THE DAY...MIXING/CHANGING TO SNOW
EARLY TO MID EVENING.
* GRADUALY BACKING OF GENERALLY 7 TO 9 KT WINDS FROM SE TO NE
TODAY AND TO N AND NW TONIGHT. WINDS TO INCREASE SOMEWHAT
TONIGHT...AVERAGING 9 TO 12 KT BY LATE EVENING.
* VFR CIGS WITH AREAS OF MVFR LOWERING IFR BY EARLY
AFTERNOON...WITH POSSIBLR LIFR CIGS LATER AFTERNOON INTO THE
NIGHT.
* REDUCED VISIBILITY...GENERALLY 2 TO 4SM REST OF DAY AND THROUGH
MUCH/ALL OF THE EVENING.
KREIN
//DISCUSSION...UPDATED 15Z...
THE NE TO SW ORIENTED UPPER TROUGH EXTENDED FROM WESTERN ONTARIO
TO N TX AT MID MORNING AND FROM WHAT NEW MODEL OUTPUT IS
AVAILABLE AT THIS TIME HAS THE TROUGH AXIS REACHING A LINE ACROSS
LAKE SUPERIOR SW TO OK. IR SATELLITE SHOWS THE CLOUDS ALONG AND
AHEAD OF THE UPPER TROUGH...WHERE ENHANCED UVV IS OCCURRING TO BE
OCCURRING...CLOUD TOPS WERE COOLING AND EXPANDING IN COVERAGE.
THE LOOP OF THE NATIONAL MOSAIC OF RADAR REFLECTIVITY WAS SHOWING
RAIN FROM EASTERN KS...NW MO AND SE IA TO W CENTRAL AND NORTHERN
IL AND SOUTHERN WI.
LOW LEVEL TEMPERATURES HAVE RISEN A COUPLE DEGREES F DURING THE
FIRST PART OF THE MORNING AS WAA CONTINUES AHEAD OF A SURFACE LOW
CURRENTLY IN CENTRAL...AND WILL PERSIST MUCH OF THE AS THE LOW
MOVES E ACROSS NORTHERN IL TO NW IN. THIS WILL KEEP PRECIP ALL
RAIN AT AND AROUND THE KLOT AND KMDW AREAS FOR THE THE REST OF
THE DAY.
AS THE SURFACE LOW MOVES ACROSS CENTRAL IL DURING THE AFTERNOON
WINDS WILL BACK FROM SE TO E AROUND MID AFTERNOON AND TO NE BY
08.00Z. MIXING/CHANGING TO SNOW WILL NOT START TO OCCUR LOCALLY
TIL EARLY EVENING WITH JUST SNOW OVERNIGHT AS THE MID AND UPPER
TROUGHS PASS E ACROSS THE LOCAL AREA AND DEEPER...STRONGER CAA
SETS IN ACROSS THE REGION.
TRS
//PREVIOUS DISCUSSION...UPDATED 12Z...
AT 11Z...TEMPERATURES ACROSS NRN IL/NWRN IN WERE 32-36F WITH EVEN
WARMER AIR OVER UPSTREAM OVER CNTRL IL AND INTO MO. WITH THE
TEMPERATURES HOVERING NEAR THE FREEZING POINT...IN LOCATIONS WHERE
PCPN HAS NOT ALREADY BEGUN...THE INITIAL ONSET OF PCPN WILL START
AS SOME LIGHT SLEET...BUT SHOULD QUICKLY CHANGE OVER TO RAIN AND
FREEZING RAIN.
THE WARMER AIR ALOFT OVER THE COOLER AIR AT THE SFC SHOULD WORK
DOWN TO THE SFC BY ARND 14Z...ENDING ANY ADDITIONAL FREEZING RAIN
POTENTIAL. THE RAIN SHOULD PERSIST THROUGH THE REMAINDER OF THE
AFTERNOON...BUT AS WINDS GRADUALLY BECOME EASTERLY...EXPECT THAT
CIGS WILL LOWER TO IFR...AND POSSIBLY LIFR...LEVELS BY THIS
AFTERNOON. THE RAIN AND IFR/LIFT CIGS WILL PERSIST UNTIL LATER
THIS EVENING WHEN A SFC LOW WILL PASS JUST SOUTH OF THE
TERMINALS...TURNING WINDS NLY-NWLY...DRAWING COOLER AIR INTO THE
AREA AND CHANGING THE RAIN OVER TO SNOW. LIGHT SNOW SHOULD PERSIST
FOR A SHORT TIME...UNTIL TAPERING OFF TO FLURRIES. AS THE COOLER
AIR WORKS INTO THE AREA...CIGS SHOULD SLOWLY IMPROVE TO MVFR
OVERNIGHT TONIGHT AND INTO TOMORROW MORNING.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN PRECIP OCCURRENCE AND TYPE THROUGH
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS REST OF DAY AND THIS EVENING.
* MEDIUM CONFIDENCE IN TIMING OF CHANGE/MIX OF RAIN AND DURING
FIRST PART OF EVENING...THEN TO ALL SNOW OVERNIGHT.
* MEDIUM CONFIDENCE IS VIS TRENDS.
* LOW CONFIDENCE IN TIMING OR EXTENT OF LIFR CIGS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 16Z...
FRIDAY NIGHT...VFR. WX NIL.
SATURDAY...VFR. WX NIL.
SUNDAY...RAIN LIKELY. IFR CONDITIONS POSSIBLE.
MONDAY...CHANCE OF RAIN AND MVFR CIGS EARLY...THEN VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
117 PM CST
WINDS VARY ACROSS THE LAKE EARLY THIS AFTERNOON AS A TROUGH OF LOW
PRESSURE CONTINUES TO MOVE NORTHEAST ACROSS PORTIONS OF THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. THIS LOW WILL CONTINUE TO
LIFT NORTHEAST TOWARDS THE OHIO VALLEY TONIGHT WHILE A RIDGE OF
HIGH PRESSURE EXTENDING FROM ONTARIO EAST TO QUEBEC SLOWLY BUILDS
SOUTHEAST. AS THIS OCCURS...EXPECT THE PRESSURE GRADIENT TO
TIGHTEN WITH WINDS INCREASING INITIALLY OUT OF THE EAST BUT THEN
SHIFTING TO MORE OF A NORTHERLY WIND TONIGHT. THESE NORTHERLY
WINDS TO 30 KT WILL CONTINUE THROUGH MOST OF FRIDAY BEFORE SLOWLY
DIMINISHING AS THIS LOW EXITS TO THE EAST AND HIGH PRESSURE BUILDS
ACROSS THE LAKE. THEN EXPECT WINDS TO CONTINUE DIMINISHING INTO
FRIDAY NIGHT AND REMAINING ON THE LIGHTER SIDE SATURDAY BEFORE
PICKING UP OUT OF THE SOUTH THROUGH THE REMAINDER OF THE DAY
SATURDAY...REMAINING SOUTHERLY THROUGH THE REST OF THE WEEKEND.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006 UNTIL MIDNIGHT FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004 UNTIL 9 PM THURSDAY.
WINTER WEATHER ADVISORY...ILZ008-ILZ011-ILZ012-ILZ013-ILZ014
UNTIL 9 PM THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
106 PM CST THU FEB 7 2013
.MESOSCALE DISCUSSION...
106 PM CST
WE HAVE OPTED TO UPGRADE LAKE AND MCHENRY COUNTIES TO A WINTER
STORM WARNING. SHORT TERM GUIDANCE AND RADAR TRENDS CONTINUES TO
INDICATE HEAVY SNOW RATES IN ACROSS LAKE AND MCHENRY COUNTIES. WE
HAVE HAD REPORTS OF UP TO 2 INCHES IN BEACH PARK WITHIN A COUPLE
HOURS.
A RATHER IMPRESSIVE SHORT WAVE...CURRENTLY DIGGING SOUTHEAST ACROSS
EASTERN NEBRASKA AND INTO WESTERN IOWA...WILL LINK UP WITH A
STRENGTHENING BAND OF MID LEVEL FRONTOGENESIS AND NEGATIVE EPV TO
RESULT IN A BAND OF VERY HEAVY SNOW ACROSS NORTHEASTERN ILLINOIS
THROUGH THE AFTERNOON. THE RAIN SHOULD BEGIN TO QUICKLY TRANSITION TO
SNOW ACROSS THE CHICAGO AREA...MAINLY ALONG AND NORTH OF THE
INTERSTATE 80 CORRIDOR BY MID AFTERNOON AS COLUMN COOL OCCURS IN
RESPONSE TO THE STRONG FRONTOGENETIC CIRCULATION. SOME OF THE LAST
AMDAR SOUNDINGS OUT OF ORD AND MDW...ONLY INDICATE A MAX TEMP OF
AROUND +1 AROUND 946 MB. SO IT WILL NOT TAKE MUCH TO TIP THE SCALES
IN FAVOR FOR SNOW. ONCE THE SNOW STARTS EXPECT HEAVY SNOW UP TO AN
INCH PER HOUR AT TIMES THROUGH THE EVENING COMMUTE. LESSER AMOUNTS
OF SNOW ARE EXPECTED FARTHER SOUTH TOWARDS THE I 80 CORRIDOR.
HOWEVER...IT MAY TAKE SOME TIME TO CHANGE OVER THIS FAR SOUTH...THUS
1 TO 3 INCHES ARE STILL POSSIBLE IN THIS AREA AS WELL INTO THE
EVENING.
SNOW AMOUNTS OF 2 TO 4 INCHES ARE LIKELY NORTH OF I-88 WITH 4 TO 8
INCHES LIKELY ACROSS LAKE AND MCHENRY COUNTIES.
KJB
&&
.DISCUSSION...
1117 AM CST
HAVE EXPANDED WINTER WEATHER ADVISORY TO INCLUDE WINNEBAGO AND BOONE
COUNTIES AND THE I-88 CORRIDOR.
RECENT AMDAR SOUNDINGS OUT OF ORD/MDW SHOW WARM LAYER UP TO JUST
UNDER +3C BETWEEN 950 AND 900 MB...WHICH LATEST RAP HAS A DECENT
HANDLE ON...RESULTING IN PLAIN RAIN FOR THE CITY AND POINTS SOUTH.
HOWEVER...TEMPERATURES AT THAT LEVEL ACROSS THE NORTHERN TIER OF
COUNTIES ARE DOWN BELOW 1C...ALREADY SUPPORTING A CHANGE TO SNOW
WITH THE CURRENT OB AT KUGN DOWN TO 1/2 MILE VSBY IN SNOW. ALSO
RECEIVED A REPORT OF SNOW STARTING TO ACCUMULATE IN WAUKEGAN AND
ZION IL AND A CHANGEOVER IN CHERRY VALLEY IL. WITH THIS IN
MIND...WILL START RIGHT OUT THE GATE WITH AN ADVISORY FOR WINNEBAGO
BOONE MCHENRY AND LAKE COUNTIES. ALSO BUMPED UP SNOW AMOUNTS TO 2 TO
5 INCHES FOR THE NORTHERN TIER GIVEN THE EARLIER START TIME TO THE
SNOW.
FARTHER TO THE SOUTH...FOR THE I-88 CORRIDOR...THE RAP ALSO SHOWS
THE 950 TO 900MB LAYER QUICKLY COOLING OFF BELOW 0C THROUGH THE
AFTERNOON INDICATIVE OF DYNAMIC COOLING. SO THESE AREAS SHOULD
CHANGE BACK OVER TO SNOW AND SEE DECENT SNOWFALL RATES GIVEN THE
FORCING AT HAND AND THE FACT THAT SURFACE TEMPERATURES EVEN NOW ARE
HOVERING JUST ABOVE FREEZING. FORECAST AMOUNTS WILL BE MARGINAL FOR
AN ADVISORY AT ROUGHLY 2 TO 4 INCHES...BUT SINCE THE RUSH HOUR WILL
BE IMPACTED...FELT IT WAS PRUDENT TO ISSUE ONE STARTING AT 20Z.
INCLUDED OGLE...DEKALB...KANE...DUPAGE AND COOK IN THIS NEW
ADVISORY...BUT KEEP IN MIND THAT THERE WILL LIKELY BE A GRADIENT
FROM NORTH TO SOUTH ACROSS DEKALB THROUGH COOK WHERE THE NORTHERN
PORTIONS WILL BE SEEING THE MORE SIGNIFICANT IMPACTS FROM THE SNOW.
WITH A GOOD FGEN BAND COINCIDENT WITH STRONG LIFT NOTED ON MUCH OF
THE GUIDANCE PIVOTING ACROSS THE CWA AND BEING LOCATED OVER
NORTHEAST ILLINOIS INCLUDING CHICAGO BY THE EARLY EVENING...ALSO
CONCERNED THAT HEAVY SNOWFALL RATES COULD LEAD TO HIGHER TOTALS THAN
THE 3 TO 5 INDICATED IN LAKE AND MCHENRY ALONG THE I-88 CORRIDOR IN
NORTHEAST ILLINOIS. WILL CONTINUE TO ASSESS FOR ANY FURTHER UPDATES
NEEDED. BUT IN SUM...THE AFTERNOON COMMUTE IS LIKELY TO BE PRETTY
MESSY...ESPECIALLY FOR THE NORTHERN PART OF THE METRO.
RC/KJB
//PREV DISCUSSION...
553 AM CST
PRECIPITATION HAS OVERSPREAD NORTHERN IL EARLY THIS MORNING WITH
TEMPERATURES INITIALLY ABOVE FREEZING. AS PRECIPITATION BECAME A
LITTLE STEADIER...TEMPERATURES HAVE FALLEN TO OR A DEGREE BELOW
FREEZING. THIS HAS RESULTED IN FREEZING RAIN BEING REPORTED ACROSS
MANY OF MY FAR NORTHEAST ILLINOIS AREAS...MAINLY ALONG AND NORTH
OF I-88. THUS HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY UNTIL
10 AM...WHICH IS THE TIME THAT TEMPS SHOULD PUSH ABOVE THE
FREEZING POINT WITH RISING DEW POINTS. PRECIPITATION AT THAT POINT
SHOULD TRANSITION OVER TO ALL RAIN.
BEACHLER
//PREV DISCUSSION...
337 AM CST
VERY DYNAMIC AND CHALLENGING WEATHER SYSTEM CONTINUES TO SLIDE EAST
FROM THE CENTRAL PLAINS TODAY. SFC TEMPS HAVE REMAINED MILD
OVERNIGHT IN THE LOW/MID 30S...WITH DEW POINTS HOVERING AROUND 30
DEG IN MANY LOCATIONS. IR IMAGERY INDICATES CONSIDERABLE CLOUD
COVER...WITH THE COLDEST CLOUDS ORIENTED FROM CENTRAL IOWA NORTHEAST
THROUGH CENTRAL WISCONSIN INTO NORTHERN LOWER MICHIGAN. EARLY THIS
MORNING CONSIDERABLE LIGHTING WAS NOTED ACROSS KANSAS AND CENTRAL
MISSOURI...INDICATING THAT CONSIDERABLE LIFT/UPGLIDE WAS OCCURRING
IN THIS AREA. IN ADDITION TO THE THUNDERSTORM ACTIVITY UPSTREAM OF
NORTHERN IL/NORTHWEST IN...WAS TEMPS IN THE LOW/MID 40S ACROSS
SOUTH CENTRAL IOWA EARLY THIS MORNING. WARM/MOIST AIR CONTINUES TO BE
TRANSPORTED NORTH FROM THE WESTERN GULF OF MEXICO AHEAD OF THE
SHORTWAVE...WHICH WILL PLAY A LARGE ROLE IN KEEPING THE BULK OF THE
PRECIP AT THE ONSET AS LIQUID. HOWEVER...A FEW SITES CONTINUE TO
SHOW TEMPS AROUND THE FREEZING MARK. THUS IT IS CONCEIVABLE THAT A
BRIEF PERIOD OF FZRA MAY OCCUR EARLY THIS MORNING. REGIONAL RADAR
MOSAIC EARLY THIS MORNING SHOWS A SLUG OF PRECIP SLIDING EAST ACROSS
NORTH CENTRAL IL/FAR WESTERN IL...HOWEVER SFC OBS INDICATE THIS IS
VERY LIGHT AND IN SOME LOCATIONS NOT REACHING THE GROUND.
THE FOCUS TURNS TOWARDS WHAT WILL TRANSPIRE BY MID-MORNING
ACROSS THE CWFA. THE GREATEST FOCUS FOR P-TYPE CONCERNS CONTINUES TO
BE ALONG AND NORTH OF A ROCKFORD TO WAUKEGAN LINE. GUIDANCE HAS
STRUGGLED WITH THE ANALYSIS AND FORECAST FIELDS OF SFC TEMPS WITH A
COLD BIAS...THUS HAVE OPTED TO MAINTAIN A SLIGHTLY WARMER TREND.
SREF 2M TEMP PLUMES CONTINUE TO SHOW MINIMAL SPREAD WITH THE TEMPS
TDY...HOWEVER APPROXIMATELY 2-3 DEG TOO COOL. CONSIDERABLE
CORRECTIONS CONTINUE TO TAKE PLACE EVEN AT HOUR ZERO AHEAD OF THIS
SYSTEM...HOWEVER SOME CONSISTENCY HAS BEEN NOTED IN THE LACK OF AN
EASTERLY LLVL JET AT 850MB. THE U-WIND ANOMS HAVE CONTINUED TO BE
POSITIVE FROM THE SW AT 20-30KTS...INDICATING AN EFFICIENT TRANSPORT
OF PARCELS FROM SW TO NE. THE WAVE REMAINS OPEN...HOWEVER SHOULD
BEGIN TO AMPLIFY WITH TIME. THE PATH OF THE 850/925MB LOWS ARE
SIMILAR AMONGST THE EC/NAM IN TIME PUSHING FROM WEST TO EAST ACROSS
THE NORTHERN THIRD OF THE CWFA MIDDAY. JUST TO THE NORTH OF THIS
PATH APPEARS TO BE THE FAVORED REGION FOR P-TYPE CONCERNS AND
ACCUMULATING SNOW POTENTIAL. THE 540M THICKNESS LINE IS JUST NORTH
OF RFD...STRETCHING SLIGHTLY SOUTHEAST OF WAUKEGAN FOR MUCH OF THE
DAY.
AS MOISTURE CONTINUES TO FEED NORTHEAST AHEAD OF THE 500MB TROUGH
AXIS...AND PRECIP OVERSPREADS THE AREA...EXPECT DYNAMIC COOLING TO
SLOWLY OCCUR ACROSS THE FAR NORTHERN CWFA INTO SOUTHERN WISC. THIS
SHOULD ALLOW A SLOW TRANSITION OVER TO A RAIN/SNOW/SLEET MIX. AT
THIS TIME ACCUMS HAVE FOCUSED FURTHER NORTH ACROSS THE STATE LINE IN
SOUTHERN WISC. SREF PLUMES FOR RFD SUGGEST A 70% PROB OF FZRA/RA AT
ONSET TRENDING TO RA...THEN ARND 21-00Z 80% LIKELIHOOD OF SN.
FURTHER EAST AT UGN THE PROB OF SN IS SLIGHTLY HIGHER AND EARLIER.
THEN BY 00Z PRECIP TYPE SHUD SWITCH OVER TO ALL SN FROM WEST TO EAST
AS COOLER AIR STEADILY ADVECTS INTO THE CWFA. SOUNDINGS ARE NOT MUCH
ASSISTANCE AT THIS TIME...GIVEN THE POOR INITIALIZATION.
SNOW ACCUMS WILL ALSO BE A CHALLENGE...IF INDEED IT DOES SNOW AND
CAN ACCUMULATE. WITH THE HIGH DEW PTS HOVERING ARND THE FREEZING
MARK IT WILL BECOME A CHALLENGE. AT THIS TIME HAVE OPTED TO TRIM
BACK SNOW ACCUMS TO A 1-2" RANGE...WITH A FOCUS ACROSS MCHENRY/LAKE
COUNTIES. HOWEVER IF THE DYNAMIC COOLING CAN TAKE PLACE
EARLIER...AND THE FGEN BAND COULD CRANK OUT HIGHER ACCUMS. VERY
DIFFICULT TO PULL THE CURRENT ADVISORY...AND AT THE SAME TIME
DIFFICULT TO EXPAND THE ADVISORY FURTHER WEST. SO AT THIS TIME WILL
LEAVE HEADLINES AS IS.
CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL...LOW.
CONFIDENCE IN PRECIP CHANGE TIMING...LOW.
TONIGHT THROUGH FRIDAY...
500MB TROUGH AXIS PIVOTS OVERHEAD AND PUSHES NORTHEAST TOWARDS THE
EASTERN GREAT LAKES EARLY FRI. 850MB/SFC LOW CONTINUES TO DEVELOP
DOWNSTREAM OF OUR AREA...WITH A DRY WEDGE ADVERTISED BY GUIDANCE
ARRIVING ARND 06-09Z. THIS SHUD AID IN SHUTTING OFF THE
PRECIP...WHICH BY 00Z FRI SHUD BE ALMOST ALL LGT SNOW. SOME
WRAP-AROUND MOISTURE CONTINUES TO BE NOTED BY THE OPERATIONAL
SOLUTIONS...THUS HAVE CONTINUED MENTION OF SOME LIGHT SNOW OR
FLURRIES ACROSS ALONG THE BACKSIDE OF THE BETTER PRECIP SHIELD.
ANTI-CYCLONIC FLOW QUICKLY BUILDS IN FOR FRI...ERODING ANY REMAINING
LLVL MOISTURE. WINDS TURN NORTHEAST FOR A PERIOD FRI WHICH COULD
PULL SOME MOISTURE OFF OF LAKE MICHIGAN...ALTHOUGH THIS LOOKS VERY
MARGINAL. THUS HAVE CONTINUE WITH A DRY FORECAST. 850MB THERMAL
TROUGH REMAINS OVERHEAD AT -4 TO -6 DEG C FRI KEEPING AFTN MAX TEMPS
MAINLY IN THE LOW/MID 30S. THE FLOW REMAINS PROGRESSIVE WITH HEIGHTS
INCREASING UPSTREAM OF THE CWFA FRI AFTN/EVE. PRIOR TO THE MID-LVL
RIDGING ARRIVING...THE SFC RIDGE WILL BECOME CENTERED OVER THE CWFA
FRI NIGHT. THIS SHUD ALLOW SFC TEMPS TO RADIATE INTO THE TEENS/LOW
20S. LIGHT WINDS AND RECENT RAINFALL FROM THURSDAY COULD SET THE
STAGE FOR PATCHY FOG DEVELOPING FRI NIGHT.
CONFIDENCE...HIGH.
SATURDAY THROUGH WEDNESDAY...
500MB RIDGING PUSHES OVERHEAD FOR SAT/SUN AS A DEEP TROUGH CONTINUES
TO DIG INTO THE FOUR-CORNERS REGION. AS THIS UPSTREAM TROUGH BECOMES
AMPLIFIED...THE WESTERN GULF OF MEXICO WILL OPEN UP WITH ABUNDANT
MOISTURE STREAMING NORTH ACROSS THE OZARKS INTO THE WESTERN GREAT
LAKES SUN. GUIDANCE HAS CONTINUED TO INDICATE THAT AFTER A DRY
SAT...SUN WILL BE WET. THIS SYSTEM ON SUN APPEARS TO BE VERY ROBUST
BASED ON LATEST GUIDANCE...WITH MINIMAL SPREAD BEING NOTED AMONGST
THE ENSEMBLE MEMBERS. AT THIS TIME HAVE HELD OFF ON INCLUDING
CONVECTION IN THE FORECAST FOR SUN...WOULDN/T BE SURPRISED TO SEE
THIS ADDED OVER TIME. TEMPS SUN SURGE AHEAD OF THE SYSTEM...WITH
MID/UPR 40S LOOKING PROBABLE. COULD EVEN SEE TEMPS TOUCH 50 DEG IN A
FEW LOCATIONS OF OUR SOUTHERN CWFA.
THEN COOLER AIR WILL RETURN FOR THE START OF NEXT WEEK...WITH TEMPS
RETURNING TO SEASONAL CONDITIONS IN THE 30S.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* RAIN THROUGH THE REST OF THE DAY...MIXING/CHANGING TO SNOW
EARLY TO MID EVENING.
* GRADUALY BACKING OF GENERALLY 7 TO 9 KT WINDS FROM SE TO NE
TODAY AND TO N AND NW TONIGHT. WINDS TO INCREASE SOMEWHAT
TONIGHT...AVERAGING 9 TO 12 KT BY LATE EVENING.
* VFR CIGS WITH AREAS OF MVFR LOWERING IFR BY EARLY
AFTERNOON...WITH POSSIBLR LIFR CIGS LATER AFTERNOON INTO THE
NIGHT.
* REDUCED VISIBILITY...GENERALLY 2 TO 4SM REST OF DAY AND THROUGH
MUCH/ALL OF THE EVENING.
KREIN
//DISCUSSION...UPDATED 15Z...
THE NE TO SW ORIENTED UPPER TROUGH EXTENDED FROM WESTERN ONTARIO
TO N TX AT MID MORNING AND FROM WHAT NEW MODEL OUTPUT IS
AVAILABLE AT THIS TIME HAS THE TROUGH AXIS REACHING A LINE ACROSS
LAKE SUPERIOR SW TO OK. IR SATELLITE SHOWS THE CLOUDS ALONG AND
AHEAD OF THE UPPER TROUGH...WHERE ENHANCED UVV IS OCCURRING TO BE
OCCURRING...CLOUD TOPS WERE COOLING AND EXPANDING IN COVERAGE.
THE LOOP OF THE NATIONAL MOSAIC OF RADAR REFLECTIVITY WAS SHOWING
RAIN FROM EASTERN KS...NW MO AND SE IA TO W CENTRAL AND NORTHERN
IL AND SOUTHERN WI.
LOW LEVEL TEMPERATURES HAVE RISEN A COUPLE DEGREES F DURING THE
FIRST PART OF THE MORNING AS WAA CONTINUES AHEAD OF A SURFACE LOW
CURRENTLY IN CENTRAL...AND WILL PERSIST MUCH OF THE AS THE LOW
MOVES E ACROSS NORTHERN IL TO NW IN. THIS WILL KEEP PRECIP ALL
RAIN AT AND AROUND THE KLOT AND KMDW AREAS FOR THE THE REST OF
THE DAY.
AS THE SURFACE LOW MOVES ACROSS CENTRAL IL DURING THE AFTERNOON
WINDS WILL BACK FROM SE TO E AROUND MID AFTERNOON AND TO NE BY
08.00Z. MIXING/CHANGING TO SNOW WILL NOT START TO OCCUR LOCALLY
TIL EARLY EVENING WITH JUST SNOW OVERNIGHT AS THE MID AND UPPER
TROUGHS PASS E ACROSS THE LOCAL AREA AND DEEPER...STRONGER CAA
SETS IN ACROSS THE REGION.
TRS
//PREVIOUS DISCUSSION...UPDATED 12Z...
AT 11Z...TEMPERATURES ACROSS NRN IL/NWRN IN WERE 32-36F WITH EVEN
WARMER AIR OVER UPSTREAM OVER CNTRL IL AND INTO MO. WITH THE
TEMPERATURES HOVERING NEAR THE FREEZING POINT...IN LOCATIONS WHERE
PCPN HAS NOT ALREADY BEGUN...THE INITIAL ONSET OF PCPN WILL START
AS SOME LIGHT SLEET...BUT SHOULD QUICKLY CHANGE OVER TO RAIN AND
FREEZING RAIN.
THE WARMER AIR ALOFT OVER THE COOLER AIR AT THE SFC SHOULD WORK
DOWN TO THE SFC BY ARND 14Z...ENDING ANY ADDITIONAL FREEZING RAIN
POTENTIAL. THE RAIN SHOULD PERSIST THROUGH THE REMAINDER OF THE
AFTERNOON...BUT AS WINDS GRADUALLY BECOME EASTERLY...EXPECT THAT
CIGS WILL LOWER TO IFR...AND POSSIBLY LIFR...LEVELS BY THIS
AFTERNOON. THE RAIN AND IFR/LIFT CIGS WILL PERSIST UNTIL LATER
THIS EVENING WHEN A SFC LOW WILL PASS JUST SOUTH OF THE
TERMINALS...TURNING WINDS NLY-NWLY...DRAWING COOLER AIR INTO THE
AREA AND CHANGING THE RAIN OVER TO SNOW. LIGHT SNOW SHOULD PERSIST
FOR A SHORT TIME...UNTIL TAPERING OFF TO FLURRIES. AS THE COOLER
AIR WORKS INTO THE AREA...CIGS SHOULD SLOWLY IMPROVE TO MVFR
OVERNIGHT TONIGHT AND INTO TOMORROW MORNING.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN PRECIP OCCURRENCE AND TYPE THROUGH
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS REST OF DAY AND THIS EVENING.
* MEDIUM CONFIDENCE IN TIMING OF CHANGE/MIX OF RAIN AND DURING
FIRST PART OF EVENING...THEN TO ALL SNOW OVERNIGHT.
* MEDIUM CONFIDENCE IS VIS TRENDS.
* LOW CONFIDENCE IN TIMING OR EXTENT OF LIFR CIGS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 16Z...
FRIDAY NIGHT...VFR. WX NIL.
SATURDAY...VFR. WX NIL.
SUNDAY...RAIN LIKELY. IFR CONDITIONS POSSIBLE.
MONDAY...CHANCE OF RAIN AND MVFR CIGS EARLY...THEN VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
320 AM CST
A RIDGE OF HIGH PRESSURE EXTENDS FROM WESTERN ONTARIO TO THE
NORTHERN PLAINS WHILE TWO LOW PRESSURE SYSTEMS DEVELOP...ONE OVER
IOWA AND ANOTHER OVER THE SOUTH HIGH PLAINS. AS THE 2 LOWS
CONSOLIDATE INTO A SINGLE LOW OVER INDIANA TONIGHT...THE HIGH WILL
BUILD INTO THE UPPER MISSISSIPPI VALLEY...LEADING TO A
STRENGTHENING NORTHERLY GRADIENT OVER THE LAKE...WITH WINDS UP TO
AROUND 30 KT DEVELOPING. ON FRIDAY THE INDIANA LOW WILL MERGE WITH
A RAPIDLY DEEPENING LOW OF THE MID ATLANTIC COAST WHILE THE HIGH
PRESSURE SPREADS OVER THE LAKE. THIS WILL LEAD TO RAPIDLY
DIMINISHING WINDS OVER THE LAKE FOR FRIDAY NIGHT AND SATURDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ005-ILZ006 UNTIL MIDNIGHT FRIDAY.
WINTER WEATHER ADVISORY...ILZ003-ILZ004 UNTIL 9 PM THURSDAY.
WINTER WEATHER ADVISORY...ILZ008-ILZ011-ILZ012-ILZ013-ILZ014
UNTIL 9 PM THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1120 AM CST THU FEB 7 2013
.DISCUSSION...
1117 AM CST
HAVE EXPANDED WINTER WEATHER ADVISORY TO INCLUDE WINNEBAGO AND BOONE
COUNTIES AND THE I-88 CORRIDOR.
RECENT AMDAR SOUNDINGS OUT OF ORD/MDW SHOW WARM LAYER UP TO JUST
UNDER +3C BETWEEN 950 AND 900 MB...WHICH LATEST RAP HAS A DECENT
HANDLE ON...RESULTING IN PLAIN RAIN FOR THE CITY AND POINTS SOUTH.
HOWEVER...TEMPERATURES AT THAT LEVEL ACROSS THE NORTHERN TIER OF
COUNTIES ARE DOWN BELOW 1C...ALREADY SUPPORTING A CHANGE TO SNOW
WITH THE CURRENT OB AT KUGN DOWN TO 1/2 MILE VSBY IN SNOW. ALSO
RECEIVED A REPORT OF SNOW STARTING TO ACCUMULATE IN WAUKEGAN AND
ZION IL AND A CHANGEOVER IN CHERRY VALLEY IL. WITH THIS IN
MIND...WILL START RIGHT OUT THE GATE WITH AN ADVISORY FOR WINNEBAGO
BOONE MCHENRY AND LAKE COUNTIES. ALSO BUMPED UP SNOW AMOUNTS TO 2 TO
5 INCHES FOR THE NORTHERN TIER GIVEN THE EARLIER START TIME TO THE
SNOW.
FARTHER TO THE SOUTH...FOR THE I-88 CORRIDOR...THE RAP ALSO SHOWS
THE 950 TO 900MB LAYER QUICKLY COOLING OFF BELOW 0C THROUGH THE
AFTERNOON INDICATIVE OF DYNAMIC COOLING. SO THESE AREAS SHOULD
CHANGE BACK OVER TO SNOW AND SEE DECENT SNOWFALL RATES GIVEN THE
FORCING AT HAND AND THE FACT THAT SURFACE TEMPERATURES EVEN NOW ARE
HOVERING JUST ABOVE FREEZING. FORECAST AMOUNTS WILL BE MARGINAL FOR
AN ADVISORY AT ROUGHLY 2 TO 4 INCHES...BUT SINCE THE RUSH HOUR WILL
BE IMPACTED...FELT IT WAS PRUDENT TO ISSUE ONE STARTING AT 20Z.
INCLUDED OGLE...DEKALB...KANE...DUPAGE AND COOK IN THIS NEW
ADVISORY...BUT KEEP IN MIND THAT THERE WILL LIKELY BE A GRADIENT
FROM NORTH TO SOUTH ACROSS DEKALB THROUGH COOK WHERE THE NORTHERN
PORTIONS WILL BE SEEING THE MORE SIGNIFICANT IMPACTS FROM THE SNOW.
WITH A GOOD FGEN BAND COINCIDENT WITH STRONG LIFT NOTED ON MUCH OF
THE GUIDANCE PIVOTING ACROSS THE CWA AND BEING LOCATED OVER
NORTHEAST ILLINOIS INCLUDING CHICAGO BY THE EARLY EVENING...ALSO
CONCERNED THAT HEAVY SNOWFALL RATES COULD LEAD TO HIGHER TOTALS THAN
THE 3 TO 5 INDICATED IN LAKE AND MCHENRY ALONG THE I-88 CORRIDOR IN
NORTHEAST ILLINOIS. WILL CONTINUE TO ASSESS FOR ANY FURTHER UPDATES
NEEDED. BUT IN SUM...THE AFTERNOON COMMUTE IS LIKELY TO BE PRETTY
MESSY...ESPECIALLY FOR THE NORTHERN PART OF THE METRO.
RC/KJB
&&
.PREV DISCUSSION...
553 AM CST
PRECIPITATION HAS OVERSPREAD NORTHERN IL EARLY THIS MORNING WITH
TEMPERATURES INITIALLY ABOVE FREEZING. AS PRECIPITATION BECAME A
LITTLE STEADIER...TEMPERATURES HAVE FALLEN TO OR A DEGREE BELOW
FREEZING. THIS HAS RESULTED IN FREEZING RAIN BEING REPORTED ACROSS
MANY OF MY FAR NORTHEAST ILLINOIS AREAS...MAINLY ALONG AND NORTH
OF I-88. THUS HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY UNTIL
10 AM...WHICH IS THE TIME THAT TEMPS SHOULD PUSH ABOVE THE
FREEZING POINT WITH RISING DEW POINTS. PRECIPITATION AT THAT POINT
SHOULD TRANSITION OVER TO ALL RAIN.
BEACHLER
//PREV DISCUSSION...
337 AM CST
VERY DYNAMIC AND CHALLENGING WEATHER SYSTEM CONTINUES TO SLIDE EAST
FROM THE CENTRAL PLAINS TODAY. SFC TEMPS HAVE REMAINED MILD
OVERNIGHT IN THE LOW/MID 30S...WITH DEW POINTS HOVERING AROUND 30
DEG IN MANY LOCATIONS. IR IMAGERY INDICATES CONSIDERABLE CLOUD
COVER...WITH THE COLDEST CLOUDS ORIENTED FROM CENTRAL IOWA NORTHEAST
THROUGH CENTRAL WISCONSIN INTO NORTHERN LOWER MICHIGAN. EARLY THIS
MORNING CONSIDERABLE LIGHTING WAS NOTED ACROSS KANSAS AND CENTRAL
MISSOURI...INDICATING THAT CONSIDERABLE LIFT/UPGLIDE WAS OCCURRING
IN THIS AREA. IN ADDITION TO THE THUNDERSTORM ACTIVITY UPSTREAM OF
NORTHERN IL/NORTHWEST IN...WAS TEMPS IN THE LOW/MID 40S ACROSS
SOUTH CENTRAL IOWA EARLY THIS MORNING. WARM/MOIST AIR CONTINUES TO BE
TRANSPORTED NORTH FROM THE WESTERN GULF OF MEXICO AHEAD OF THE
SHORTWAVE...WHICH WILL PLAY A LARGE ROLE IN KEEPING THE BULK OF THE
PRECIP AT THE ONSET AS LIQUID. HOWEVER...A FEW SITES CONTINUE TO
SHOW TEMPS AROUND THE FREEZING MARK. THUS IT IS CONCEIVABLE THAT A
BRIEF PERIOD OF FZRA MAY OCCUR EARLY THIS MORNING. REGIONAL RADAR
MOSAIC EARLY THIS MORNING SHOWS A SLUG OF PRECIP SLIDING EAST ACROSS
NORTH CENTRAL IL/FAR WESTERN IL...HOWEVER SFC OBS INDICATE THIS IS
VERY LIGHT AND IN SOME LOCATIONS NOT REACHING THE GROUND.
THE FOCUS TURNS TOWARDS WHAT WILL TRANSPIRE BY MID-MORNING
ACROSS THE CWFA. THE GREATEST FOCUS FOR P-TYPE CONCERNS CONTINUES TO
BE ALONG AND NORTH OF A ROCKFORD TO WAUKEGAN LINE. GUIDANCE HAS
STRUGGLED WITH THE ANALYSIS AND FORECAST FIELDS OF SFC TEMPS WITH A
COLD BIAS...THUS HAVE OPTED TO MAINTAIN A SLIGHTLY WARMER TREND.
SREF 2M TEMP PLUMES CONTINUE TO SHOW MINIMAL SPREAD WITH THE TEMPS
TDY...HOWEVER APPROXIMATELY 2-3 DEG TOO COOL. CONSIDERABLE
CORRECTIONS CONTINUE TO TAKE PLACE EVEN AT HOUR ZERO AHEAD OF THIS
SYSTEM...HOWEVER SOME CONSISTENCY HAS BEEN NOTED IN THE LACK OF AN
EASTERLY LLVL JET AT 850MB. THE U-WIND ANOMS HAVE CONTINUED TO BE
POSITIVE FROM THE SW AT 20-30KTS...INDICATING AN EFFICIENT TRANSPORT
OF PARCELS FROM SW TO NE. THE WAVE REMAINS OPEN...HOWEVER SHOULD
BEGIN TO AMPLIFY WITH TIME. THE PATH OF THE 850/925MB LOWS ARE
SIMILAR AMONGST THE EC/NAM IN TIME PUSHING FROM WEST TO EAST ACROSS
THE NORTHERN THIRD OF THE CWFA MIDDAY. JUST TO THE NORTH OF THIS
PATH APPEARS TO BE THE FAVORED REGION FOR P-TYPE CONCERNS AND
ACCUMULATING SNOW POTENTIAL. THE 540M THICKNESS LINE IS JUST NORTH
OF RFD...STRETCHING SLIGHTLY SOUTHEAST OF WAUKEGAN FOR MUCH OF THE
DAY.
AS MOISTURE CONTINUES TO FEED NORTHEAST AHEAD OF THE 500MB TROUGH
AXIS...AND PRECIP OVERSPREADS THE AREA...EXPECT DYNAMIC COOLING TO
SLOWLY OCCUR ACROSS THE FAR NORTHERN CWFA INTO SOUTHERN WISC. THIS
SHOULD ALLOW A SLOW TRANSITION OVER TO A RAIN/SNOW/SLEET MIX. AT
THIS TIME ACCUMS HAVE FOCUSED FURTHER NORTH ACROSS THE STATE LINE IN
SOUTHERN WISC. SREF PLUMES FOR RFD SUGGEST A 70% PROB OF FZRA/RA AT
ONSET TRENDING TO RA...THEN ARND 21-00Z 80% LIKELIHOOD OF SN.
FURTHER EAST AT UGN THE PROB OF SN IS SLIGHTLY HIGHER AND EARLIER.
THEN BY 00Z PRECIP TYPE SHUD SWITCH OVER TO ALL SN FROM WEST TO EAST
AS COOLER AIR STEADILY ADVECTS INTO THE CWFA. SOUNDINGS ARE NOT MUCH
ASSISTANCE AT THIS TIME...GIVEN THE POOR INITIALIZATION.
SNOW ACCUMS WILL ALSO BE A CHALLENGE...IF INDEED IT DOES SNOW AND
CAN ACCUMULATE. WITH THE HIGH DEW PTS HOVERING ARND THE FREEZING
MARK IT WILL BECOME A CHALLENGE. AT THIS TIME HAVE OPTED TO TRIM
BACK SNOW ACCUMS TO A 1-2" RANGE...WITH A FOCUS ACROSS MCHENRY/LAKE
COUNTIES. HOWEVER IF THE DYNAMIC COOLING CAN TAKE PLACE
EARLIER...AND THE FGEN BAND COULD CRANK OUT HIGHER ACCUMS. VERY
DIFFICULT TO PULL THE CURRENT ADVISORY...AND AT THE SAME TIME
DIFFICULT TO EXPAND THE ADVISORY FURTHER WEST. SO AT THIS TIME WILL
LEAVE HEADLINES AS IS.
CONFIDENCE IN TEMPERATURES...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL...LOW.
CONFIDENCE IN PRECIP CHANGE TIMING...LOW.
TONIGHT THROUGH FRIDAY...
500MB TROUGH AXIS PIVOTS OVERHEAD AND PUSHES NORTHEAST TOWARDS THE
EASTERN GREAT LAKES EARLY FRI. 850MB/SFC LOW CONTINUES TO DEVELOP
DOWNSTREAM OF OUR AREA...WITH A DRY WEDGE ADVERTISED BY GUIDANCE
ARRIVING ARND 06-09Z. THIS SHUD AID IN SHUTTING OFF THE
PRECIP...WHICH BY 00Z FRI SHUD BE ALMOST ALL LGT SNOW. SOME
WRAP-AROUND MOISTURE CONTINUES TO BE NOTED BY THE OPERATIONAL
SOLUTIONS...THUS HAVE CONTINUED MENTION OF SOME LIGHT SNOW OR
FLURRIES ACROSS ALONG THE BACKSIDE OF THE BETTER PRECIP SHIELD.
ANTI-CYCLONIC FLOW QUICKLY BUILDS IN FOR FRI...ERODING ANY REMAINING
LLVL MOISTURE. WINDS TURN NORTHEAST FOR A PERIOD FRI WHICH COULD
PULL SOME MOISTURE OFF OF LAKE MICHIGAN...ALTHOUGH THIS LOOKS VERY
MARGINAL. THUS HAVE CONTINUE WITH A DRY FORECAST. 850MB THERMAL
TROUGH REMAINS OVERHEAD AT -4 TO -6 DEG C FRI KEEPING AFTN MAX TEMPS
MAINLY IN THE LOW/MID 30S. THE FLOW REMAINS PROGRESSIVE WITH HEIGHTS
INCREASING UPSTREAM OF THE CWFA FRI AFTN/EVE. PRIOR TO THE MID-LVL
RIDGING ARRIVING...THE SFC RIDGE WILL BECOME CENTERED OVER THE CWFA
FRI NIGHT. THIS SHUD ALLOW SFC TEMPS TO RADIATE INTO THE TEENS/LOW
20S. LIGHT WINDS AND RECENT RAINFALL FROM THURSDAY COULD SET THE
STAGE FOR PATCHY FOG DEVELOPING FRI NIGHT.
CONFIDENCE...HIGH.
SATURDAY THROUGH WEDNESDAY...
500MB RIDGING PUSHES OVERHEAD FOR SAT/SUN AS A DEEP TROUGH CONTINUES
TO DIG INTO THE FOUR-CORNERS REGION. AS THIS UPSTREAM TROUGH BECOMES
AMPLIFIED...THE WESTERN GULF OF MEXICO WILL OPEN UP WITH ABUNDANT
MOISTURE STREAMING NORTH ACROSS THE OZARKS INTO THE WESTERN GREAT
LAKES SUN. GUIDANCE HAS CONTINUED TO INDICATE THAT AFTER A DRY
SAT...SUN WILL BE WET. THIS SYSTEM ON SUN APPEARS TO BE VERY ROBUST
BASED ON LATEST GUIDANCE...WITH MINIMAL SPREAD BEING NOTED AMONGST
THE ENSEMBLE MEMBERS. AT THIS TIME HAVE HELD OFF ON INCLUDING
CONVECTION IN THE FORECAST FOR SUN...WOULDN/T BE SURPRISED TO SEE
THIS ADDED OVER TIME. TEMPS SUN SURGE AHEAD OF THE SYSTEM...WITH
MID/UPR 40S LOOKING PROBABLE. COULD EVEN SEE TEMPS TOUCH 50 DEG IN A
FEW LOCATIONS OF OUR SOUTHERN CWFA.
THEN COOLER AIR WILL RETURN FOR THE START OF NEXT WEEK...WITH TEMPS
RETURNING TO SEASONAL CONDITIONS IN THE 30S.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* RAIN THROUGH THE REST OF THE DAY...MIXING/CHANGING TO SNOW
EARLY TO MID EVENING.
* GRADUALY BACKING OF GENERALLY 7 TO 9 KT WINDS FROM SE TO NE
TODAY AND TO N AND NW TONIGHT. WINDS TO INCREASE SOMEWHAT
TONIGHT...AVERAGING 9 TO 12 KT BY LATE EVENING.
* VFR CIGS WITH AREAS OF MVFR LOWERING IFR BY EARLY
AFTERNOON...WITH POSSIBLR LIFR CIGS LATER AFTERNOON INTO THE
NIGHT.
* REDUCED VISIBILITY...GENERALLY 2 TO 4SM REST OF DAY AND THROUGH
MUCH/ALL OF THE EVENING.
KREIN
//DISCUSSION...UPDATED 15Z...
THE NE TO SW ORIENTED UPPER TROUGH EXTENDED FROM WESTERN ONTARIO
TO N TX AT MID MORNING AND FROM WHAT NEW MODEL OUTPUT IS
AVAILABLE AT THIS TIME HAS THE TROUGH AXIS REACHING A LINE ACROSS
LAKE SUPERIOR SW TO OK. IR SATELLITE SHOWS THE CLOUDS ALONG AND
AHEAD OF THE UPPER TROUGH...WHERE ENHANCED UVV IS OCCURRING TO BE
OCCURRING...CLOUD TOPS WERE COOLING AND EXPANDING IN COVERAGE.
THE LOOP OF THE NATIONAL MOSAIC OF RADAR REFLECTIVITY WAS SHOWING
RAIN FROM EASTERN KS...NW MO AND SE IA TO W CENTRAL AND NORTHERN
IL AND SOUTHERN WI.
LOW LEVEL TEMPERATURES HAVE RISEN A COUPLE DEGREES F DURING THE
FIRST PART OF THE MORNING AS WAA CONTINUES AHEAD OF A SURFACE LOW
CURRENTLY IN CENTRAL...AND WILL PERSIST MUCH OF THE AS THE LOW
MOVES E ACROSS NORTHERN IL TO NW IN. THIS WILL KEEP PRECIP ALL
RAIN AT AND AROUND THE KLOT AND KMDW AREAS FOR THE THE REST OF
THE DAY.
AS THE SURFACE LOW MOVES ACROSS CENTRAL IL DURING THE AFTERNOON
WINDS WILL BACK FROM SE TO E AROUND MID AFTERNOON AND TO NE BY
08.00Z. MIXING/CHANGING TO SNOW WILL NOT START TO OCCUR LOCALLY
TIL EARLY EVENING WITH JUST SNOW OVERNIGHT AS THE MID AND UPPER
TROUGHS PASS E ACROSS THE LOCAL AREA AND DEEPER...STRONGER CAA
SETS IN ACROSS THE REGION.
TRS
//PREVIOUS DISCUSSION...UPDATED 12Z...
AT 11Z...TEMPERATURES ACROSS NRN IL/NWRN IN WERE 32-36F WITH EVEN
WARMER AIR OVER UPSTREAM OVER CNTRL IL AND INTO MO. WITH THE
TEMPERATURES HOVERING NEAR THE FREEZING POINT...IN LOCATIONS WHERE
PCPN HAS NOT ALREADY BEGUN...THE INITIAL ONSET OF PCPN WILL START
AS SOME LIGHT SLEET...BUT SHOULD QUICKLY CHANGE OVER TO RAIN AND
FREEZING RAIN.
THE WARMER AIR ALOFT OVER THE COOLER AIR AT THE SFC SHOULD WORK
DOWN TO THE SFC BY ARND 14Z...ENDING ANY ADDITIONAL FREEZING RAIN
POTENTIAL. THE RAIN SHOULD PERSIST THROUGH THE REMAINDER OF THE
AFTERNOON...BUT AS WINDS GRADUALLY BECOME EASTERLY...EXPECT THAT
CIGS WILL LOWER TO IFR...AND POSSIBLY LIFR...LEVELS BY THIS
AFTERNOON. THE RAIN AND IFR/LIFT CIGS WILL PERSIST UNTIL LATER
THIS EVENING WHEN A SFC LOW WILL PASS JUST SOUTH OF THE
TERMINALS...TURNING WINDS NLY-NWLY...DRAWING COOLER AIR INTO THE
AREA AND CHANGING THE RAIN OVER TO SNOW. LIGHT SNOW SHOULD PERSIST
FOR A SHORT TIME...UNTIL TAPERING OFF TO FLURRIES. AS THE COOLER
AIR WORKS INTO THE AREA...CIGS SHOULD SLOWLY IMPROVE TO MVFR
OVERNIGHT TONIGHT AND INTO TOMORROW MORNING.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN PRECIP OCCURRENCE AND TYPE THROUGH
AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS REST OF DAY AND THIS EVENING.
* MEDIUM CONFIDENCE IN TIMING OF CHANGE/MIX OF RAIN AND DURING
FIRST PART OF EVENING...THEN TO ALL SNOW OVERNIGHT.
* MEDIUM CONFIDENCE IS VIS TRENDS.
* LOW CONFIDENCE IN TIMING OR EXTENT OF LIFR CIGS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 16Z...
FRIDAY NIGHT...VFR. WX NIL.
SATURDAY...VFR. WX NIL.
SUNDAY...RAIN LIKELY. IFR CONDITIONS POSSIBLE.
MONDAY...CHANCE OF RAIN AND MVFR CIGS EARLY...THEN VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
320 AM CST
A RIDGE OF HIGH PRESSURE EXTENDS FROM WESTERN ONTARIO TO THE
NORTHERN PLAINS WHILE TWO LOW PRESSURE SYSTEMS DEVELOP...ONE OVER
IOWA AND ANOTHER OVER THE SOUTH HIGH PLAINS. AS THE 2 LOWS
CONSOLIDATE INTO A SINGLE LOW OVER INDIANA TONIGHT...THE HIGH WILL
BUILD INTO THE UPPER MISSISSIPPI VALLEY...LEADING TO A
STRENGTHENING NORTHERLY GRADIENT OVER THE LAKE...WITH WINDS UP TO
AROUND 30 KT DEVELOPING. ON FRIDAY THE INDIANA LOW WILL MERGE WITH
A RAPIDLY DEEPENING LOW OF THE MID ATLANTIC COAST WHILE THE HIGH
PRESSURE SPREADS OVER THE LAKE. THIS WILL LEAD TO RAPIDLY
DIMINISHING WINDS OVER THE LAKE FOR FRIDAY NIGHT AND SATURDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006 UNTIL 9 PM
THURSDAY.
WINTER WEATHER ADVISORY...ILZ008-ILZ011-ILZ012-ILZ013-ILZ014
UNTIL 9 PM THURSDAY.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
304 PM CST THU FEB 7 2013
.SYNOPSIS...
12Z UA ANALYSIS HAS A WEAK 850MB LOW IN NORTHWEST MISSOURI WITH
ANOTHER IN THE OKLAHOMA PANHANDLE. A MOISTURE PLUME RAN FROM THE
GULF UP INTO THE MID MISSISSIPPI VALLEY WITH A STRONGER MOISTURE
PLUME OVER THE SOUTHEAST CONUS. RADAR TRENDS THROUGH MID AFTERNOON
CONTINUE TO SHOW WIDESPREAD RAIN ACROSS THE AREA WITH A MIX AND
CHANGE OVER TO SNOW ROUGHLY ALONG THE WI/IL BORDER.
18Z SFC ANALYSIS HAS A WEAK LOW WEST OF KMUT WITH A WARM FRONT
RUNNING ROUGHLY EAST ALONG I-80. THE COLD FRONT RAN SOUTH INTO
NORTHEAST OKLAHOMA. SEVERAL INVERTED TROFS RAN FROM THE LOW INTO
WISCONSIN AND SOUTHEAST MINNESOTA. DEW POINTS WERE IN THE 40S AND
50S ACROSS THE LOWER MISSISSIPPI VALLEY WITH 20S AND 30S OVER THE
GREAT LAKES AND MID MISSISSIPPI VALLEY.
&&
.SHORT TERM...TONIGHT AND FRIDAY...
DYNAMIC COOLING OF THE ATMOSPHERIC COLUMN HAS ALLOWED A MIX AND
CHANGE OVER TO SNOW ALONG THE HWY 20 CORRIDOR EAST OF KDBQ. CAA IS
NOW OCCURRING ACROSS THE FAR WESTERN PART OF THE CWFA BUT NO DYNAMIC
COOLING OF THE ATMOSPHERE HAS OCCURRED YET.
PER THE RAP TRENDS...DYNAMIC COOLING OF THE ATMOSPHERE WILL CONTINUE
TO SLOWLY PUSH THE MIX AND CHANGE OVER TO THE SOUTH LATE THIS
AFTERNOON AND EARLY EVENING FROM ROUGHLY THE MISSISSIPPI ON EAST AND
NORTH OF I-80. MINOR ACCUMULATIONS ARE POSSIBLE ON GRASSY SURFACES
WITH THE HIGHEST AMOUNTS OF 1-1.5 INCHES ALONG THE HWY 20 CORRIDOR
EAST OF KDBQ.
ACROSS THE REMAINDER OF THE CWFA IT WILL BE A RACE BETWEEN THE RAIN
ENDING AND THE COLD AIR ARRIVING. TRENDS WITH THE RAP SUGGEST A MIX
DEVELOPING JUST PRIOR TO THE RAIN ENDING OVER THE WESTERN HALF WITH
THE SOUTHERN MOST EXTENT ABOUT I-80.
THUS THE OVERALL SCENARIO IS ONE OF PRECIPITATION ENDING FROM WEST
TO EAST LATE THIS AFTERNOON THROUGH MIDNIGHT. BY MID EVENING AREAS
GENERALLY WEST OF A KDBQ TO KMQB LINE SHOULD BE DRY DUE TO DOWNWARD
MOTION AND INCREASING CONDENSATION PRESSURE DEFICITS.
AFTER MIDNIGHT...DRY CONDITIONS ARE EXPECTED. THE LARGE EXTENT OF
LOW CLOUDS UP INTO THE NORTHERN PLAINS INDICATES THAT CLEARING WILL
BE SLOW TO OCCUR. BREAKS IN THE CLOUD COVER SHOULD DEVELOP LATE
TONIGHT WITH CLEARING OCCURRING IN ERNEST STARTING AROUND SUNRISE.
QUIET AND DRY CONDITIONS WILL BE SEEN ON FRIDAY AS HIGH PRESSURE
BUILDS INTO THE AREA. SKIES WILL CONTINUE TO CLEAR DURING THE DAY
WITH MOSTLY SUNNY CONDITIONS EXPECTED BY MID AFTERNOON. ..08..
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
OUR ATTENTION THIS LONG TERM FORECAST CONTINUES TO BE THE LARGE
SYNOPTIC STORM SET FOR THE WEEKEND INTO EARLY NEXT WEEK. GLOBAL AND
CONUS MODELS ARE IN GREAT AGREEMENT ON GENERAL DETAILS SHOWING A
DEEP/CLOSED UPPER TROF EXITING THE ROCKIES SATURDAY...SWEEPING
NORTHEAST SUNDAY...WHILE A STRONG SURFACE LOW MOVES FROM THE WESTERN
PLAINS TO SOUTHERN MN BY SUNDAY NIGHT. THIS PATH WILL BRING STRONG
SOUTH WINDS...AND MILD AIR TO THE REGION SATURDAY THROUGH
SUNDAY...ALONG WITH A PERIOD OF HIGH PROBABILITY RAIN SHOWERS AND
POSSIBLE THUNDER. RAINFALL TOTALS OF 0.25 TO 0.75 ARE CERTAINLY
POSSIBLE GIVEN THE STRONG FORCING...BUT ARE NOT LIKELY TO GET MUCH
HIGHER GIVEN THE PRONOUNCED DRY SLOT FORECAST TO SWEEP THROUGH THE
CWA SUNDAY AFTERNOON. BEHIND THIS SYSTEM...ALL MODELS SHOW WRAP
AROUND OCCLUDED LIGHT SNOW OR SNOW SHOWERS EITHER IN OUR NORTH
HALF...OR JUST NORTH OF THE CWA BORDER. THUS...SOME LOW POPS ARE IN
THE FORECAST FOR SUNDAY NIGHT AND MONDAY NORTH...AND DEPENDING ON
HOW THIS ALL UNFOLDS...THEY MAY NEED TO BE EXPANDED.
TEMPERATURES ARE ON THE MILD SIDE OF A GUIDANCE BLEND THROUGH THE
FORECAST GIVEN OUR HIGHLY CHANGEABLE SNOW COVER SITUATION TODAY. AT
THIS TIME...IT DOES APPEAR MOST IF NOT ALL SNOW SHOULD BE GONE BY
SUNDAY NIGHT. THUS...THE COLD INTRUSION BEHIND THIS LARGE SYSTEM MAY
LACK MUCH POTENCY.
ERVIN
&&
.AVIATION...
COOLING OF THE ATMOSPHERE WILL ALLOW THE RAIN TO CHANGE TO SNOW AT
KDBQ WITH A POSSIBLE MIX DEVELOPING AT KCID/KMLI. VLIFR/LIFR
CONDITIONS WILL CONTINUE THROUGH 00Z/08 WITH SLOW IMPROVEMENT TO
IFR/MVFR THROUGH 12Z/08. AFT 12Z/08 CONDITIONS WILL IMPROVE TO VFR
AS HIGH PRESSURE BUILDS INTO THE MIDWEST. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1237 PM CST THU FEB 7 2013
.UPDATE...
BASED ON SFC OBS AND MORE RECENT RAP TRENDS...MIXED PRECIPITATION
SHOULD BEGIN IN THE HWY 20 CORRIDOR FROM KDBQ EAST AROUND MID
AFTERNOON. WBZ TEMPERATURES ARE STILL ABOVE FREEZING AT THE SFC
BUT AS CAA DEVELOPS WITH THE PASSAGE OF THE LOW...DYNAMIC COOLING
OF THE OVERALL ATMOSPHERIC COLUMN WILL OCCUR. SINCE SFC
TEMPERATURES WILL REMAIN ABOVE FREEZING THERE MAY BE A MINOR SLUSHY
ACCUMULATION POSSIBLE.
ACROSS THE WESTERN CWFA...CAA DURING THE AFTERNOON SHOULD ALSO
ALLOW A RA/SN MIX AS COOLING OF THE ATMOSPHERIC OCCURS. WBZ
TEMPERATURES ARE PROJECTED TO REMAIN ABOVE FREEZING AS WELL BUT
SOME VERY MINOR ACCUMULATIONS MAY OCCUR ON GRASSY SURFACES. ..08..
.PREV DISCUSSION... /ISSUED 1056 AM CST THU FEB 7 2013/
UPDATE...
THE PRECIPITATION APPEARS TO CONFORM REASONABLY WELL WITH THE
290K THETA SFC. BASED ON RAP TRENDS RAIN WILL CONTINUE THROUGH
THE AFTERNOON. FCST SOUNDINGS FROM THE RAP SHOW CAA OCCURRING FROM
WEST TO EAST DURING THE AFTERNOON WHICH SHOULD RESULT IN A MIX
DEVELOPING ACROSS THE FAR WEST BY MID AFTERNOON THAT SLOWLY MOVES
EAST.
AS THE BETTER FORCING MOVES EAST DURING THE AFTERNOON HOURS THE
PRECIPITATION WILL BECOME LESS INTENSE AND SLOWLY END FROM WEST TO
EAST AS WELL. HOWEVER...IT NOW APPEARS THAT PRECIPITATION WILL
LINGER INTO THE EVENING HOURS...ESPECIALLY EAST OF THE
MISSISSIPPI. FCST SOUNDINGS CONTINUE TO COOL BUT THE PRECIPITATION
WILL BE NEARLY OVER BY THE TIME THE COLD AIR ARRIVES.
SNOW AMOUNTS WILL BE VERY MINIMAL WITH AMOUNTS BEING A DUSTING AT
BEST. ..08..
AVIATION...
FOR THE 18Z TAFS...IFR TO LIFR CONDITIONS WILL CONTINUE THROUGH
THROUGH 00Z/08 BEFORE IMPROVING TO MVFR AS LOW PRESSURE MOVES INTO
THE GREAT LAKES FROM MISSOURI. THE MODELS INDICATE SKIES SHOULD
CLEAR BY SUNRISE FRIDAY RESULTING IN VFR CONDITIONS. ..08..
PREV DISCUSSION... /ISSUED 400 AM CST THU FEB 7 2013/
SYNOPSIS...
THE 2 AM SURFACE AND RADAR ANALYSIS DEPICTS AREA OF DEVELOPING RAIN
WITH SOME EMBEDDED THUNDER TO OVERSPREAD THE FORECAST AREA THE NEXT
6-9 HOURS BEFORE MOVING NORTHEAST. SURFACE TEMPERATURES MILDER AND
WETTER THAN MOST/ALL SOLUTIONS SUPPORTING MODERATE RAIN TOTALS WITH
TEMPERATURES ABOVE FREEZING. NOWCAST TOOLS SUPPORT AREA OF HEAVIEST
RAIN TO FALL ROUGHLY ALONG THE CONCEPTUAL TRIPLE POINT WHICH SHOULD BE
+/- 25 NM EITHER SIDE OF A OTM TO SQI AXIS. UPSTREAM ANALYSIS SUPPORTS
NEXT SYSTEM TO AFFECT AREA LATE IN THE WEEKEND TO BE RAIN OR MOSTLY RAIN
EVENT WITH LIGHT TO MODERATE RAIN TOTALS.
SHORT TERM...TODAY AND TONIGHT...
TODAY...THE "LIFT" TOOL SUPPORTS ISOLATED EMBEDDED THUNDER ALONG WAA
WING AXIS AHEAD OF VORT MAX OVER SOUTHEAST 1/2 TO 2/3 AREA. HAVE
CATEGORICAL POPS WITH WIDESPREAD EVENT RAIN TOTALS OF 1/3 TO 2/3 OF
AN INCH. WARMER TEMPERATURES TO MITIGATE FOG TO AREAS OR PATCHY
WITH VISIBILITIES MOSTLY AOA 1 MILE ATTM. THIS WILL NEED TO BE
REASSESSED AS SFC LOW CONVERGENCE WILL BE THE KEY THIS AM FOR AREAS
OF DENSE FOG. TRENDS SUGGEST SNOW OR POSSIBLY SOME SLEET ON BACKSIDE
THIS LATE PM AND EARLY EVENING HOURS WITH LITTLE OR NO ACCUMULATIONS.
HIGHS SHOULD BE 40 TO 45 SOUTH WITH MID DAY MAX TEMPS AND NORTH 35
TO 40 DEGREES WITH SLOW FALL IN PM HOURS.
TONIGHT...REDUCED POPS WITH ANY LINGERING LIGHT PRECIPITATION TO EXIT
FAR EAST SECTIONS BY 9 PM. CLOUDY SKIES WITH NW WINDS OF 10-15 KTS
AND SUBSIDENCE SHOULD CLEAR BETWEEN 03-09Z MOST LOCATIONS. MINS IN
THE LOWER 20S NW WITH NEAR 30 DEGREES FAR SE SECTIONS. LATER SHIFTS
MAY NEED TO ADJUST MINS BY A CATEGORY OR MORE IF CLEARING IS FASTER
OR SLOWER.
NICHOLS
LONG TERM...FRIDAY THROUGH WEDNESDAY...
FOCUS REMAINS ON LARGE STORM SYSTEM LIFTING OUT OF THE SOUTHWEST
SATURDAY NIGHT THROUGH SUNDAY NIGHT. THIS IS STILL LOOKING TO BE
PRIMARILY A RAIN SYSTEM FOR THE REGION.
00Z MODEL RUNS ARE IN SOMEWHAT AGREEMENT WITH THE SURFACE AND UPPER
LEVEL LOWS TRACKING WELL NORTHWEST OF THE FORECAST SUNDAY AND SUNDAY
NIGHT AND OVERALL...ONLY A FEW CHANGES MADE TO THE FORECAST.
PRECIPITATION WILL DEVELOP SATURDAY NIGHT IN A WARM ADVECTION
WING...INITIALLY IN THE WEST...SPREADING INTO THE EAST AND NORTHEAST
BY SUNRISE. THE OVERALL SETUP APPEARS SIMILAR TO THE ON-GOING
SYSTEM...THAT IS SOUTHEAST WINDS AND CLOUD COVER WILL RESULT IN A
NEAR STEADY TO TEMPERATURE TREND FROM LATE AFTERNOON THROUGH
OVERNIGHT. AFTER A WARM SATURDAY...WITH TEMPERATURES REACHING IN THE
30S NORTH AND MID 40S SOUTH...READINGS WILL LIKELY REMAIN IN THE 30S
THROUGH THE NIGHT. MODELS APPEAR TO AGAIN BE OVERDOING THE COLD AIR
AT THE SURFACE. FOR NOW...WILL INCLUDE A POSSIBLE RAIN/SNOW MIX AT
ONSET ACROSS THE NORTH AND NORTHEAST. BASED ON INCREASING CONFIDENCE
ON EVENT TIMING...HAVE RAISED POPS TO LIKELY IN THE WEST AND ADDED A
MENTION OF THUNDER IN THE FAR SOUTHWEST WHERE STRONGEST FORCING AND
SUFFICIENTLY STEEP MID LEVEL LAPSE RATES OF BOTH THETA E AND
TEMPERATURES COINCIDE.
SUNDAY...CATEGORICAL POPS COVER ALL BUT THE FAR SOUTH FOR MODERATE
RAINFALL AMOUNTS WITH ISOLATED THUNDERSTORMS. WARM ADVECTION OF A
GULF AIRMASS WILL PUSH TEMPERATURES AND DEWPOINTS WELL INTO THE 40S
AND POSSIBLY LOWER 50S SOUTH. A LARGE DRY SLOT AND TRAILING OCCLUDED
FRONT WILL PUSH THROUGH SUNDAY NIGHT...AND HAVE LOWERED POPS TO
SLIGHT CHANCES IN THE SOUTH. THERMAL PROFILES SUGGEST POSSIBLY BRIEF
CHANGE OVER TO SNOW BEFORE ENDING...BUT LITTLE IF ANY ACCUMULATIONS
ARE EXPECTED.
MONDAY THROUGH WEDNESDAY....MODEL CONSENSUS SUPPORTS AN OVERALL DRY
FORECAST WITH TEMPERATURES TRENDING BACK CLOSER TO MID FEB NORMALS.
SHEETS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1150 AM CST THU FEB 7 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN IS WITH ONGOING RAIN AND SMALL POTENTIAL FOR
FZRA/IP/SN THIS MORNING. EXPECTING THE RAIN TO PERSIST THROUGH MUCH
OF THE MORNING BEFORE SHIFTING EAST BY AROUND 18Z OR EARLIER. LEANED
TOWARD THE NAM12 AS IT HAS THE BEST HANDLE ON CURRENT RADAR TRENDS.
THE HIRES WRF MODEL RUNS AND HRRR HAVE MUCH OF THE PRECIP CONFINED
TO THE SOUTHEAST BY 18Z AS WELL.
THE COLD FRONT...CURRENTLY LOCATED ACROSS NORTHERN IOWA JUST SOUTH
OF A MASON CITY TO SAC CITY LINE WILL CONTINUE TO SHIFT SOUTH
THROUGH THE MORNING HOURS. CAA INCREASES BY MID TO LATE MORNING AND
FRONT SHOULD CLEAR THE FORECAST AREA BY AROUND 18Z EXCEPT FOR THE
FAR SOUTHEAST. FORECAST SOUNDINGS AT MCW/ALO INDICATING SOME ICE
INTRODUCTION AT THE TOP OF THE SNOW GROWTH ZONE...BUT A DEEP DRY
LAYER B/T 600-900MB ENTRAIN INTO THIS AREA WITH THE CAA. STILL HAVE
SOME SATURATION NEAR THE SURFACE AND MIGHT BE DEEP ENOUGH FOR FZDZ.
HAVE INCLUDED MENTION OF FZDZ THROUGH THE MORNING. OTHERWISE ANY
PRECIP FALLING ALOFT LOOKS TO HAVE A TOUGH TIME REACHING THE GROUND
WITH THAT LARGE DRY LAYER. SEEMS TO BE MATCHING WELL WITH CURRENT
TRENDS AS NOT SEEING ANY PRECIP NEAR MCW/ALO ATTM. SO HAVE LOW
CONFIDENCE WITH ANY MIXED PRECIP THIS MORNING...SO LOWERED POPS THIS
MORNING AND WENT DRY BY THIS AFTERNOON OVER THE NORTHEAST. FURTHER
SOUTH...EXPECTING PRECIP TO REMAIN ALL RAIN AS TIMING OF COLD AIR IS
DELAYED UNTIL AFTER RAIN HAS DISSIPATED. NO MAJOR CHANGES TO
TEMPERATURE TREND WITH THE COLD FRONT MOVING THROUGH...SO KEPT
MENTION OF THE NON-DIURNAL TREND.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
WEEKEND SYSTEM WILL BE THE ONLY SIGNIFICANT CONCERN THIS PERIOD.
SENSIBLE WEATHER WITH CURRENT SYSTEM SHOULD HAVE DEPARTED IA BY 00Z
LEADING TO FAIR WEATHER AND EVENTUALLY MODERATING TEMPERATURES TO
END THE WEEK AS HIGH PRESSURE CROSSES THE UPPER MS VALLEY INTO THE
GREAT LAKES. THE WEATHER CHANGES QUICKLY BY SAT NIGHT HOWEVER AND
MODELS CONTINUE TO SHOW GOOD AGREEMENT WITH EVOLUTION OF THIS SYSTEM
LEADING TO RELATIVELY HIGH CONFIDENCE. ECMWF/GFS BOTH DEPICT SHARP
INCREASE IN FORCING 3KM AND BELOW INCLUDING IMPRESSIVE WARM AIR AND
THETA-E ADVECTION. THIS SURGE WILL ALSO LEAD TO LOWER STATIC
STABILITIES AS SUGGESTED BY TOKEN ELEVATED CAPES AND INCREASING K
INDICES. THIS HAS LEAD TO A MENTION OF ISOLATED THUNDER SOUTH LATE
SAT NIGHT AND EARLY SUN...SIMILAR TO WHAT IS PRESENTLY OCCURRING
SOUTH THIS MORNING. MUCH LIKE WHAT WAS SHOWN YESTERDAY...1-3KM
SURGE OF FORCING IS CLOSELY FOLLOWED BY DIVERGENCE AHEAD OF UPPER
LEVEL LOW AND DIFFERENTIAL PVA ON THE NOSE OF THE DRY SLOT. THIS
HAS LEAD TO CATEGORICAL POPS OVERNIGHT INTO SUN MORNING WHICH IS
ALSO SUPPORTED BY GEFS AND SREF PRECIP PROBS. SIGNIFICANT PRECIP
SHOULD THEN END BY SUN NIGHT WITH LINGERING WRAP AROUND MOISTURE BUT
LITTLE IN THE WAY OF FORCING.
EVEN THOUGH THERE IS RELATIVELY HIGHER CONFIDENCE IN SYSTEM TRACK
AND PRECIPITATION EVOLUTION...WARM LAYER TEMPS WILL STILL BE
HOVERING AROUND CRITICAL 1-3C VALUES NORTH KEEPING PRECIP TYPE IN
QUESTION THERE. EVOLUTION OF RAW MODEL SURFACE TEMPS...AND
DEPICTION OF ECMWF/GFS/GEM WARM LAYERS ALOFT...SUGGEST A WINTRY
MIXED BAG OF PRECIP NE QUARTER-THIRD SAT NIGHT INTO EARLY SUN
SWITCHING TO RAIN FORECAST AREA WIDE BY LATE MORNING. EXPECT SOME
SORT OF TRAVEL PROBLEMS EARLY SUN WHICH WILL BE HIGHLIGHTED IN THE
HWO...BUT DETAILS DIFFICULT AT THIS POINT. FOR INSTANCE MCW
SOUNDINGS AT 12Z SUN...NEAR THE PEAK UVM...RANGE FROM GEM/SREF ALL
SNOW...TO ECMWF RAIN/SNOW MIX...TO NAM/GFS AT OR NEARLY ALL LIQUID
WITH A 3-4C WARM LAYER AND ALL WITH SURFACE TEMPS PLUS/MINUS 32F.
SYSTEM MAY JUST LINGER INTO MON NORTH BUT ESSENTIALLY BE DONE BY
THAT TIME. MAIN STORY FOR MON WILL LIKELY BE GUSTY WNW WINDS.
OTHER MODELS LESS BULLISH...BUT GFS SHOWS MCW GUSTS OVER 40 MPH.
THIS THEN LEADS TO FAIR WEATHER FOR THE HEART OF THE NEXT WORK WEEK
WITH LITTLE IN THE WAY OF FORCING OR MOISTURE WITH MIDWEST IN
INACTIVE NW FLOW BEHIND DEPARTING LONG WAVE TROUGH AND AHEAD OF WRN
CONUS OR ROCKIES RIDGE.
&&
.AVIATION...07/18Z
-RA WILL CONTINUE TO AFFECT EASTERN SITES...KALO/KOTM THROUGH 00Z.
LARGE AREA OF MVFR AND IFR STRATUS WILL REMAIN IN PLACE ACROSS STATE
THROUGH MUCH OF THE PERIOD. WINDS WILL INCREASE WITH GUSTS POSSIBLE
IN THE AFTERNOON. CEILINGS MAY LIFT TO HIGH MVFR AND POSSIBLY VFR
NEAR END OF PERIOD AS A WEAK HIGH PRESSURE RIDGE PUSHES ACROSS THE
AREA. BUT CONTINUED LOW LEVEL MOISTURE WILL ALSO LEAD TO THE
POSSIBILITY OF CONTINUED MVFR AND IFR VISIBILITIES THROUGH END OF
PERIOD...BUT DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE MENTION ATTM
AND WILL HAVE TO BE MONITORED.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1056 AM CST THU FEB 7 2013
.UPDATE...
THE PRECIPITATION APPEARS TO CONFORM REASONABLY WELL WITH THE
290K THETA SFC. BASED ON RAP TRENDS RAIN WILL CONTINUE THROUGH
THE AFTERNOON. FCST SOUNDINGS FROM THE RAP SHOW CAA OCCURRING FROM
WEST TO EAST DURING THE AFTERNOON WHICH SHOULD RESULT IN A MIX
DEVELOPING ACROSS THE FAR WEST BY MID AFTERNOON THAT SLOWLY MOVES
EAST.
AS THE BETTER FORCING MOVES EAST DURING THE AFTERNOON HOURS THE
PRECIPITATION WILL BECOME LESS INTENSE AND SLOWLY END FROM WEST TO
EAST AS WELL. HOWEVER...IT NOW APPEARS THAT PRECIPITATION WILL
LINGER INTO THE EVENING HOURS...ESPECIALLY EAST OF THE
MISSISSIPPI. FCST SOUNDINGS CONTINUE TO COOL BUT THE PRECIPITATION
WILL BE NEARLY OVER BY THE TIME THE COLD AIR ARRIVES.
SNOW AMOUNTS WILL BE VERY MINIMAL WITH AMOUNTS BEING A DUSTING AT
BEST. ..08..
&&
.AVIATION...
FOR THE 18Z TAFS...IFR TO LIFR CONDITIONS WILL CONTINUE THROUGH
THROUGH 00Z/08 BEFORE IMPROVING TO MVFR AS LOW PRESSURE MOVES INTO
THE GREAT LAKES FROM MISSOURI. THE MODELS INDICATE SKIES SHOULD
CLEAR BY SUNRISE FRIDAY RESULTING IN VFR CONDITIONS. ..08..
&&
.PREV DISCUSSION... /ISSUED 400 AM CST THU FEB 7 2013/
SYNOPSIS...
THE 2 AM SURFACE AND RADAR ANALYSIS DEPICTS AREA OF DEVELOPING RAIN
WITH SOME EMBEDDED THUNDER TO OVERSPREAD THE FORECAST AREA THE NEXT
6-9 HOURS BEFORE MOVING NORTHEAST. SURFACE TEMPERATURES MILDER AND
WETTER THAN MOST/ALL SOLUTIONS SUPPORTING MODERATE RAIN TOTALS WITH
TEMPERATURES ABOVE FREEZING. NOWCAST TOOLS SUPPORT AREA OF HEAVIEST
RAIN TO FALL ROUGHLY ALONG THE CONCEPTUAL TRIPLE POINT WHICH SHOULD BE
+/- 25 NM EITHER SIDE OF A OTM TO SQI AXIS. UPSTREAM ANALYSIS SUPPORTS
NEXT SYSTEM TO AFFECT AREA LATE IN THE WEEKEND TO BE RAIN OR MOSTLY RAIN
EVENT WITH LIGHT TO MODERATE RAIN TOTALS.
SHORT TERM...TODAY AND TONIGHT...
TODAY...THE "LIFT" TOOL SUPPORTS ISOLATED EMBEDDED THUNDER ALONG WAA
WING AXIS AHEAD OF VORT MAX OVER SOUTHEAST 1/2 TO 2/3 AREA. HAVE
CATEGORICAL POPS WITH WIDESPREAD EVENT RAIN TOTALS OF 1/3 TO 2/3 OF
AN INCH. WARMER TEMPERATURES TO MITIGATE FOG TO AREAS OR PATCHY
WITH VISIBILITIES MOSTLY AOA 1 MILE ATTM. THIS WILL NEED TO BE
REASSESSED AS SFC LOW CONVERGENCE WILL BE THE KEY THIS AM FOR AREAS
OF DENSE FOG. TRENDS SUGGEST SNOW OR POSSIBLY SOME SLEET ON BACKSIDE
THIS LATE PM AND EARLY EVENING HOURS WITH LITTLE OR NO ACCUMULATIONS.
HIGHS SHOULD BE 40 TO 45 SOUTH WITH MID DAY MAX TEMPS AND NORTH 35
TO 40 DEGREES WITH SLOW FALL IN PM HOURS.
TONIGHT...REDUCED POPS WITH ANY LINGERING LIGHT PRECIPITATION TO EXIT
FAR EAST SECTIONS BY 9 PM. CLOUDY SKIES WITH NW WINDS OF 10-15 KTS
AND SUBSIDENCE SHOULD CLEAR BETWEEN 03-09Z MOST LOCATIONS. MINS IN
THE LOWER 20S NW WITH NEAR 30 DEGREES FAR SE SECTIONS. LATER SHIFTS
MAY NEED TO ADJUST MINS BY A CATEGORY OR MORE IF CLEARING IS FASTER
OR SLOWER.
NICHOLS
LONG TERM...FRIDAY THROUGH WEDNESDAY...
FOCUS REMAINS ON LARGE STORM SYSTEM LIFTING OUT OF THE SOUTHWEST
SATURDAY NIGHT THROUGH SUNDAY NIGHT. THIS IS STILL LOOKING TO BE
PRIMARILY A RAIN SYSTEM FOR THE REGION.
00Z MODEL RUNS ARE IN SOMEWHAT AGREEMENT WITH THE SURFACE AND UPPER
LEVEL LOWS TRACKING WELL NORTHWEST OF THE FORECAST SUNDAY AND SUNDAY
NIGHT AND OVERALL...ONLY A FEW CHANGES MADE TO THE FORECAST.
PRECIPITATION WILL DEVELOP SATURDAY NIGHT IN A WARM ADVECTION
WING...INITIALLY IN THE WEST...SPREADING INTO THE EAST AND NORTHEAST
BY SUNRISE. THE OVERALL SETUP APPEARS SIMILAR TO THE ON-GOING
SYSTEM...THAT IS SOUTHEAST WINDS AND CLOUD COVER WILL RESULT IN A
NEAR STEADY TO TEMPERATURE TREND FROM LATE AFTERNOON THROUGH
OVERNIGHT. AFTER A WARM SATURDAY...WITH TEMPERATURES REACHING IN THE
30S NORTH AND MID 40S SOUTH...READINGS WILL LIKELY REMAIN IN THE 30S
THROUGH THE NIGHT. MODELS APPEAR TO AGAIN BE OVERDOING THE COLD AIR
AT THE SURFACE. FOR NOW...WILL INCLUDE A POSSIBLE RAIN/SNOW MIX AT
ONSET ACROSS THE NORTH AND NORTHEAST. BASED ON INCREASING CONFIDENCE
ON EVENT TIMING...HAVE RAISED POPS TO LIKELY IN THE WEST AND ADDED A
MENTION OF THUNDER IN THE FAR SOUTHWEST WHERE STRONGEST FORCING AND
SUFFICIENTLY STEEP MID LEVEL LAPSE RATES OF BOTH THETA E AND
TEMPERATURES COINCIDE.
SUNDAY...CATEGORICAL POPS COVER ALL BUT THE FAR SOUTH FOR MODERATE
RAINFALL AMOUNTS WITH ISOLATED THUNDERSTORMS. WARM ADVECTION OF A
GULF AIRMASS WILL PUSH TEMPERATURES AND DEWPOINTS WELL INTO THE 40S
AND POSSIBLY LOWER 50S SOUTH. A LARGE DRY SLOT AND TRAILING OCCLUDED
FRONT WILL PUSH THROUGH SUNDAY NIGHT...AND HAVE LOWERED POPS TO
SLIGHT CHANCES IN THE SOUTH. THERMAL PROFILES SUGGEST POSSIBLY BRIEF
CHANGE OVER TO SNOW BEFORE ENDING...BUT LITTLE IF ANY ACCUMULATIONS
ARE EXPECTED.
MONDAY THROUGH WEDNESDAY....MODEL CONSENSUS SUPPORTS AN OVERALL DRY
FORECAST WITH TEMPERATURES TRENDING BACK CLOSER TO MID FEB NORMALS.
SHEETS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
313 PM CST THU FEB 7 2013
.DISCUSSION...
TONIGHT THROUGH FRIDAY...
THE TAIL-END OF THE MORNING RAIN SHOWERS WERE SKIMMING ACROSS EAST
CENTRAL AND SOUTHEAST KANSAS THIS AFTERNOON. NORTH-NORTHWESTERLY
FLOW PREVAILED ACROSS THE REGION WITH THE COLD FRONT HAVING
PROGRESSED EAST OF THE CWA EARLIER TODAY.
TONIGHT INTO FRIDAY...A WEAK RIDGE WILL BUILD INTO THE CENTRAL CONUS
AHEAD OF THE NEXT SYSTEM THAT WILL PROGRESS INTO THE CENTRAL U.S.
THIS WEEKEND. SURFACE HIGH PRESSURE SITUATED OVER THE NORTHERN
PLAINS THIS AFTERNOON WILL SPILL SOUTHWARD INTO THE CENTRAL PLAINS
TONIGHT INTO FRIDAY. ONE AREA OF UNCERTAINTY IS WITH REGARDS TO THE
STRATUS DECK CURRENTLY UNDER THIS SURFACE HIGH AND WHETHER OR NOT
THE NORTHERLY FLOW WILL PUSH THIS DECK SOUTHWARD INTO EXTREME
NORTHEAST AND EASTERN KANSAS THIS EVENING. THE RAP IS THE MOST
AGGRESSIVE IN HOLDING LOW-LEVEL MOISTURE IN ACROSS NORTHEASTERN
KANSAS OVERNIGHT WHILE THE NAM/GFS/ECMWF SHOWS THE DRY AIR THAT IS
WEST OF THE CWA PREVAILING AND RESULTING IN CLEARING SKIES ACROSS
MUCH OF THE FORECAST AREA OVERNIGHT. WHETHER THIS STRATUS DECK
STRETCHES INTO THE REGION WILL ALSO IMPACT WHETHER THERE IS A
POTENTIAL FOR SOME PATCHY FOG TO DEVELOP EARLY FRIDAY MORNING DUE TO
THE LIGHT NORTHERLY WINDS AND THE PRESENCE OF SURFACE MOISTURE FROM
THE RAIN SHOWERS THIS MORNING. HAVE NOT ADDED ANY MENTION OF PATCHY
FOG IN THE FORECAST ATTM DUE TO THE UNCERTAINTY WITH THE MOVEMENT OF
THE STRATUS DECK...BUT WILL CONTINUE TO MONITOR THIS EVENING.
AS FOR TEMPERATURES...NORTHERLY FLOW WILL HELP TO DROP OVERNIGHT
LOWS INTO THE 20S. AS THE SURFACE HIGH SHIFTS EAST OF THE REGION ON
FRIDAY...WINDS WILL VEER TO THE EAST-SOUTHEAST WITH AFTERNOON HIGHS
RANGING FROM THE MID 40S OVER NORTHEAST KANSAS TO THE LOWER 50S
ACROSS CENTRAL KANSAS.
ACH
FRIDAY NIGHT THROUGH THURSDAY...
AN UPPER LEVEL TROUGH WILL DIG SOUTHEAST FROM THE PACIFIC NORTHWEST
INTO THE FOUR CORNERS AREA LATE FRIDAY NIGHT...THEN LIFT NORTHEAST
INTO THE CENTRAL AND SOUTHERN PLAINS SATURDAY NIGHT INTO SUNDAY.
SATURDAY THROUGH SATURDAY NIGHT...A LEE SURFACE LOW WILL DEVELOP
ACROSS EASTERN CO DURING THE DAY ON SATURDAY...THEN DEEPEN AHEAD OF
THE APPROACHING UPPER LEVEL TROUGH. SOUTHERLY LOW LEVEL WINDS AHEAD
OF THE LEE SURFACE LOW WILL ADVECT DEEPER GULF MOISTURE NORTHWARD
ACROSS EASTERN KS SATURDAY AFTERNOON AND EVENING. WAA/ISENTROPIC
LIFT WILL CAUSE SHOWERS TO DEVELOP ACROSS THE SOUTHERN COUNTIES OF
THE CWA THURSDAY AFTERNOON...THEN LIFT NORTHEAST ACROSS THE CWA
DURING THE EARLY EVENING HOURS. THE 12Z NAM AND ECMWF SHOW MUCAPE
INCREASING TO 300 TO 700 J/KG ACROSS THE CWA...THUS SCATTERED
ELEVATED THUNDERSTORMS WILL BE POSSIBLE ALONG WITH NUMEROUS SHOWERS
SATURDAY NIGHT INTO SUNDAY MORNING. THE SFC-6KM BULK SHEAR WILL BE
ABOUT 50 TO 60 KTS...THUS SOME OF THE STRONGER ELEVATED
THUNDERSTORMS MAY BE CAPABLE OF PRODUCING SMALL HAIL SATURDAY NIGHT.
WE MAY RECEIVE A QUARTER TO ONE HALF INCH OF RAINFALL...WITH SOME
LOCALLY HIGHER AMOUNTS SATURDAY NIGHT INTO SUNDAY MORNING.
SUNDAY...THE UPPER LEVEL TROUGH WILL LIFT NORTHEAST ACROSS NORTHWEST
KS INTO SOUTHWEST MN WHILE THE SURFACE LOW MOVES NORTHEAST ACROSS
EASTERN NE INTO NORTH CENTRAL IA. A PACIFIC COLD FRONT WILL MOVE
EAST ACROSS THE CWA DURING THE MORNING HOURS OF SUNDAY...AND WILL
BRING AN END TO THE SHOWERS AND SCATTERED THUNDERSTORMS ACROSS THE
EASTERN COUNTIES OF THE CWA. SKIES WILL CLEAR FROM SOUTHWEST TO
NORTHEAST ACROSS THE CWA...DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS. THE WRAP AROUND PRECIP SHOULD REMAIN NORTH OF THE
STATE LINE...THOUGH CLOUDS AND PERHAPS SOME SPRINKLES OR FLURRIES
COULD DEVELOP ACROSS THE NORTHERN COUNTIES OF THE CWA DURING THE MID
AND LATE AFTERNOON HOURS. HIGHS ACROSS NORTH CENTRAL KS MAY BE
REACHED AROUND NOON...WITH SLOWLY FALLING TEMPERATURES INTO THE
UPPER 30S. THE REMAINDER OF THE CWA WILL WARM INTO THE UPPER 40S TO
MID 50S ACROSS EAST CENTRAL KS.
SUNDAY NIGHT THROUGH TUESDAY NIGHT...A SECOND UPPER LEVEL TROUGH
WILL DIG SOUTHWARD ACROSS THE WEST-CENTRAL CONUS INTO NM...THEN WILL
MOVE EAST ACROSS NORTH TX AND OK WHILE SHEARING OUT MONDAY NIGHT. THE
STRONGER ASCENT AND PRECIP CHANCES WILL OCCUR WELL SOUTH OF THE
CWA ACROSS SOUTHWEST KS AND OK. HIGHS WILL BE IN THE LOWER TO MID
40S. LOWS WILL BE IN THE 20S.
WEDNESDAY THROUGH THURSDAY...AN UPPER LEVEL TROUGH WILL MOVE ONSHORE
ACROSS THE PACIFIC NORTHWEST...THEN DIG SOUTHEAST ACROSS THE
NORTHERN AND CENTRAL PLAINS ON THURSDAY. AHEAD OF THE H5 TROUGH
TEMPERATURES WILL WARM INTO THE MID TO UPPER 40S. IF THE COLD FRONT
IS A BIT FASTER...THEN HIGH TEMPS ON THURSDAY WILL BE CAT OR TWO
COOLER. THE LOW-LEVELS OF THE ATMOSPHERE LOOK TOO DRY FOR ANY
MEASURABLE PRECIP. THE STRONGER ASCENT AHEAD OF THIS H5 TROUGH WILL
OCCUR ACROSS THE UPPER MIDWEST AND MID MS RIVER VALLEY...WELL
NORTHEAST OF THE CWA.
GARGAN
&&
.AVIATION...
FOR 18Z TAFS...THE MORNING SHOWERS HAVE PASSED EAST OF THE TAF
SITES...RESULTING IN A RETURN TO VFR CONDITIONS WHICH WILL CONTINUE
THROUGH THE PERIOD. SCATTERED MID-LEVEL CLOUDS WILL STILL BE IN
PLACE THROUGH THE AFTERNOON HOURS BEFORE CLEARING OUT EARLY THIS
EVENING THROUGH FRIDAY. NORTHERLY WINDS THIS AFTERNOON COULD RESULT
IN A FEW GUSTS UPWARDS OF AROUND 20KTS BUT WILL WEAKEN TONIGHT. BY
MID FRIDAY MORNING...WINDS WILL VEER TOWARD THE EAST AS HIGH
PRESSURE DIPS SOUTHWARD INTO THE REGION.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1203 PM CST THU FEB 7 2013
...UPDATE TO AVIATION...
.DISCUSSION...
MAIN AREA OF PRECIPITATION SO FAR HAS BEEN JUST UPSTREAM OF BEST
LOW-MID LEVEL MOISTURE CONVERGENCE WHERE STRONGER LOW LEVEL JET IS
BEING MAINTAINED EAST OF 850MB LOW. UPPER WAVE CONTINUES ITS
EASTWARD PROGRESS BUT HAS STILL JUST ENTERED THE PLAINS AT 08Z.
LATEST RAP AND 06Z NAM TAKE THIS AREA OF CONVERGENCE EAST THROUGH
THE POST-SUNRISE HOURS WHILE THE UPPER WAVE...CONTINUING TO SLOW
ITS PACE...HELPS SPREAD PRECIP NORTHEAST. THIS WILL KEEP PRECIP IN
PLACE SLIGHTLY LONGER...BUT A QUICK CLEARING IS ON TRACK FOR THE
AFTERNOON AS THE UPPER TROF CLEARS KANSAS. WEAKENING LAPSE RATES
AND LESS-FOCUSED LIFT SHOULD KEEP THUNDERSTORMS IN A ISOLATED
NATURE. MODEST COLD AIR ADVECTION AND GOOD MIXING SHOULD STILL
PUSH HIGHS INTO THE UPPER 40S TO LOWER 50S.
DEEP RIDING TO BE THE RULE INTO FRIDAY. HIGHS FRIDAY STILL SOMEWHAT
IN QUESTION WITH EASTERLY WINDS AND INCREASING HIGH CLOUDS BUT KEPT
TEMPS JUST ABOVE MOS VALUES GIVEN THEIR COOL BIAS THIS SEASON.
PRECIP CHANCES RAMP UP AGAIN SATURDAY INTO SATURDAY NIGHT AS THE
NEXT SYSTEM...ENTERING THE PACIFIC NORTHWEST IN RECENT
HOURS...EMERGES FROM THE ROCKIES. INCREASING SOUTH WINDS AND LARGE
SCALE FORCING BRINGS SOME CHANCE FOR SHOWERS BY SATURDAY
AFTERNOON...WITH THE WETTEST PERIOD EXPECTED SATURDAY NIGHT AS THE
LOW SURGES NORTHEAST INTO THE PLAINS. INSTABILITY DOES NOT LOOK
IMPRESSIVE...BUT ENOUGH FORCING MECHANISMS COME TOGETHER FOR SOME
THUNDER POTENTIAL AGAIN. TEMPS STAY WARM ENOUGH FOR AN ALL LIQUID
EVENT UNTIL PERHAPS SUNDAY AFTERNOON AS COLD AIR COMES IN BEHIND THE
LOW...BUT MEASURABLE AMOUNTS SEEM UNLIKELY AT BEST. SECONDARY SYSTEM
WORKING IN BEHIND WILL NEED TO BE WATCHED...BUT THE BULK OF IT
SHOULD REMAIN SOUTH. WILL INCLUDE SMALL OPPORTUNITIES FOR PRECIP
TUESDAY NIGHT IN FAR SOUTHERN AREAS.
65
&&
.AVIATION...
FOR 18Z TAFS...THE MORNING SHOWERS HAVE PASSED EAST OF THE TAF
SITES...RESULTING IN A RETURN TO VFR CONDITIONS WHICH WILL CONTINUE
THROUGH THE PERIOD. SCATTERED MID-LEVEL CLOUDS WILL STILL BE IN
PLACE THROUGH THE AFTERNOON HOURS BEFORE CLEARING OUT EARLY THIS
EVENING THROUGH FRIDAY. NORTHERLY WINDS THIS AFTERNOON COULD RESULT
IN A FEW GUSTS UPWARDS OF AROUND 20KTS BUT WILL WEAKEN TONIGHT. BY
MID FRIDAY MORNING...WINDS WILL VEER TOWARD THE EAST AS HIGH
PRESSURE DIPS SOUTHWARD INTO THE REGION.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
258 PM CST THU FEB 7 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 257 PM CST THU FEB 7 2013
BASED ON CURRENT RADAR...LINE OF SHOWERS WILL REACH FAR WESTERN
PORTIONS OF THE PAH FORECAST AREA AROUND 22Z...SPREADING ACROSS
SOUTHEAST MISSOURI INTO SOUTHERN ILLINOIS BETWEEN 00Z AND
02Z...REACHING FAR WEST KENTUCKY AND SOUTHWEST INDIANA BETWEEN 02Z
AND 03Z...THEN INTO THE PENNYRILE REGION OF WEST KENTUCKY LATE
THIS EVENING. THE NAM12 AND RUC LINE UP WELL WITH THIS
TIMING...AND THE NAM HAS PRECIP CLEARING THE PAH FA BY 12Z FRIDAY.
HAVE LIKELY TO CATEGORICAL POPS ACROSS THE ENTIRE FA FOR A LEAST A
FEW HOURS SHIFTING FROM WEST TO EAST BETWEEN 00Z AND 10Z. INCLUDED
SOME ISOLATED THUNDER CHANCES ACROSS THE SOUTHERN HALF OF THE
REGION THIS EVENING BASED ON LIGHTNING DATA OCCASIONALLY SHOWING A
FEW STRIKES IN SOUTHERN MISSOURI AND NAM AND SREF SHOWING NEAR
ZERO LI`S MAKING IT INTO THE AREA....ESPECIALLY IN SOUTHEAST
MISSOURI. ANY THUNDER POSSIBILITY SHOULD END BY MIDNIGHT.
DRY AND COOLER WEATHER IS EXPECTED FRIDAY INTO FRIDAY NIGHT AS
HIGH PRESSURE SLIDES THROUGH THE GREAT LAKES REGION. RH TIME
HEIGHTS SHOW VERY DRY AIR ACROSS THE REGION...SO WE SHOULD SEE
LOTS OF SUNSHINE ON FRIDAY AND MOSTLY CLEAR SKIES INTO FRIDAY
NIGHT. TEMPERATURES WILL BE NEAR SEASONAL FRIDAY AND FRIDAY
NIGHT...THEN A FEW DEGREES WARMER FOR SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 257 PM CST THU FEB 7 2013
00Z AND 12Z RUNS CONFIRM A FASTER APPROACH/PASSAGE OF THE WEEKEND
WEATHER SYSTEM OF NOTE. THE 12Z GFS IS NOW TRACKING THE SURFACE AND
UPPER LOWS FROM THE PLAINS STATES...NORTHEASTWARD TO THE GREAT
LAKES...A SUBTLE NORTHWARD SHIFT MORE AKIN TO THE 12Z YESTERDAY AND
00Z EURO TRACKS. BOTH MODELS PUSH THE FRONT OUT AHEAD AND SPEED UP
THE INTRO/PASSAGE/DEPARTURE OF PCPN FOR OUR AREA. THIS WILL
TRANSLATE TO INTRODUCTORY POPS SAT NIGHT...PEAK POPS SUNDAY...WITH
ENDING/DEPARTURE POPS SUNDAY NIGHT.
THE SYSTEM WILL HAVE MAINLY ELEVATED INSTABILITY...WITH THE MAX
SURFACE INSTABILITY AXIS FOCUSED ALONG THE LOWER MS VALLEY TO THE
GULF COAST. THIS IS BASED ON A RIBBON OF 50F TD MAKING ITS WAY INTO
OUR AREA...AND THIS AXIS COULD EXTEND FURTHER NORTHWARD IF TDS DO IN
FACT CLIMB HIGHER. STILL...WITH THE COLD FRONT INCOMING...AND
POWERFUL WIND FIELDS ALOFT...A DAMAGING WIND THREAT WILL ACCOMPANY
STORMS SHOULD THEY DEVELOP/BECOME SVR. BRN MAG TO 100KTS MIGRATES
ACROSS THE FA WITH THE SYSTEM/WHILE WEAK BULLSEYES OF 0-2KM VORT GEN
AND LAYER TOR PARAMETERS SUGGEST ISOLD TORS ARE POSSIBLE TOO. WILL
CONTINUE THE HIGHLIGHT OF THIS POSSIBILITY VIA THE HWO.
WITH POWERFUL WINDS PROPELLING THE SYSTEM THRU...WE SHOULD SEE QUICK
BURST QPF OF 1/2 TO 1 INCH ON AVERAGE FOR THE BASINS. HOWEVER...WITH
GFS SOUNDINGS REVEALING 1-1.25" PW`S PUSHING THE 99TH PERCENTILE FOR
THIS TIME OF YEAR...LOCALIZED HEAVIER RAINFALL COULD CREATE SOME
FLOOD ISSUES/OR AT LEAST CAUSE HEIGHTENED CONCERN/SOMETHING TO KEEP
AN EYE UPON.
MONDAY-TUESDAY...THE MODELS BACK OFF SOMEWHAT ON THE
STALLED/RETURNING BOUNDARY SCENARIO ACROSS OUR SOUTHERN COUNTIES. SO
WE`LL CONTINUE TO OMIT FOR THIS PACKAGE...AND WE`LL GO AHEAD AND
KEEP THE CLEAN FROPA AND RETURN POPS IF/WHEN NEEDED...IF FUTURE RUNS
SUGGEST SO. ONE SUCH TIME IS TUESDAY NIGHT. WE WENT SLGT CHC PCN AS
2NDARY TROF/LOW ROTATES ACROSS AREA. GIVEN THERMAL PROFILE AT THAT
TIME/WE CARRY EITHER/OR -RA/-SN. MINIMAL QPF EVENT BUT ALL
CONSIDERED AND WITH COLLAB...CURSORY SLGT CHC WARRANTED FOR NOW.
THE WARM PRE-FRONTAL ENVIRO WILL COOL FROM HIGHS IN THE 50S/NR 60
EARLY...BACK TO THE MORE FEBRUARY LIKE 40S BY MID WEEK. LOWS WILL
RESPOND IN KIND...RETURNING CLOSER TO NORMS BY THEN AS WELL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 257 PM CST THU FEB 7 2013
LOW LEVEL MOIST ADVECTION AHEAD OF THE APPROACHING COLD FRONT MAY
YIELD TEMPO MVFR CIGS LATE THIS PM...BUT GENERALLY...VFR WILL CARRY
THE DAYLIGHT HOURS. AFTER NIGHTFALL...EXPECT DETERIORATING
CONDITIONS TO MVFR CIGS/VSBYS WITH RAIN CHANCE ONSET AS COLD FRONT
ENTERS FLIGHT ZONES. FROPA BY MID EVENING WILL SHIFT WINDS TO N-NWLY
OVERNIGHT WITH ACCOMPANYING GUSTS TO 20 KTS AT TIMES. SOME CHANCE OF
EMBEDDED HEAVIER RAIN REDUCING CIGS/VSBYS TO IFR FOR A BRIEF WINDOW
OF TIME IN THE EVENING...OTHERWISE MVFR CONDITIONS SHOULD IMPROVE TO
VFR BY LATE IN THE PLANNING PERIOD.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...RST
LONG TERM...DH
AVIATION...DH
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
330 PM EST THU FEB 7 2013
.SHORT TERM...THIS EVENING THROUGH FRIDAY
COMPACT WAVE ALONG THE SOUTHERN PERIPHERY OF THE NORTHERN STREAM IS
CLIPPING EAST/SOUTHEAST THROUGH THE WESTERN GREAT LAKES THIS
AFTERNOON. LOWER TROPOSPHERIC FLOW HAS INCREASED IN ADVANCE OF THIS
FEATURE ALONG THE MID-MISSISSIPPI VALLEY MANIFESTING IN A BROAD
REGION OF RAIN ACROSS ILLINOIS SOUTH INTO ARKANSAS WITH SNOW
SPREADING ACROSS WISCONSIN AND FAR WESTERN LOWER MICHIGAN.
MID-LEVEL FORCING REMAINS IN PLACE ACROSS THE SAGINAW VALLEY /AS
EVIDENCED BY LOW-LEVEL WATER VAPOR IMAGERY/ WAITING FOR MOISTURE
TRANSPORT TO ARRIVE. EXPECTING SATURATION TO OCCUR WITHIN THIS ZONE
OF FORCING BY SUNDOWN...AFTER WHICH ACCUMULATING SNOWFALL WILL
QUICKLY FOLLOW.
MEANWHILE...THE WELL ESTABLISHED MOISTURE PLUME IS WAITING ON THE
UPPER-LEVEL PV ANOMALY OVER MINNESOTA TO LINK UP AND SHOULD BEGIN TO
BREAK TOWARD THE EAST THIS EVENING. CONSEQUENTLY...THE ONSET OF
MEANINGFUL SNOW SOUTH OF THE SAGINAW VALLEY WILL BE DURING THE LATE
EVENING HOURS AS THE WARM/MOIST CONVEYOR BELT FINALLY ARRIVES. IN
FACT...THE 07.18 RAP SUGGESTS PRECIPITATION ONSET WILL BE LAGGING
UNTIL AROUND MIDNIGHT IN MANY LOCATIONS. FURTHERMORE...12Z GUIDANCE
SUITE IS TOO BULLISH ON PRECIPITATION DURING THE FIRST 12 HOURS OF
THE FORECAST...OWING TO THE LACK OF DEEP MOISTURE TRANSPORT THUS FAR.
THE DURATION OF THE EVENT WILL CERTAINLY LIMIT ACCUMULATIONS SOUTH
OF THE MID-LEVEL FRONTAL FORCING...WHERE THE PRIMARY MECHANISM WILL
BE A QUICK BUT STRONG SHOT OF ISENTROPIC ASCENT ASSOCIATED WITH THE
SHARPENING MID-LEVEL ANOMALY. STILL EXPECT A GOOD BURST OF
PRECIPITATION /SNOW RATES IN THE INCH PER HOUR NEIGHBORHOOD/ GIVEN
THE SYSTEM WILL STILL BE DEEPENING AS IT TRAVERSES THE SOUTHERN
LAKES REGION. TO ADD FUEL TO THE RATES...THERE IS STILL THE
POTENTIAL FOR SOME CONVECTIVE CONTRIBUTION CLOSER TO THE 850MB LOW
TRACK...WHERE DIFFERENTIAL ADVECTIONS WILL DESTABILIZE THE PROFILE.
STILL PLENTY OF EVIDENCE TO SUPPORT A MIXTURE OF PRECIPITATION TYPES
ACROSS THE METRO DETROIT REGION SOUTH TO THE OHIO BORDER. THE BEST
OPPORTUNITY FOR FREEZING RAIN AND SLEET WILL BE NEAR THE ONSET OF
PRECIPITATION...BEFORE THE COLUMN SUCCUMBS TO COOLING VIA STRONG
ASCENT ALONG THE LEAD EDGE OF THE PV ANOMALY.
ON FRIDAY...SOME LIGHT SNOW WILL CONTINUE THROUGH THE MORNING AS
MID-LEVEL DEFORMATION LINGERS FOR SEVERAL HOURS. CLOSER TO LAKE
HURON...THE INCREASING NORTHEASTERLY FLOW WILL HELP BOOST SNOW
TOTALS ALONG THE IMMEDIATE LAKESHORE.
HIGH PRESSURE WILL QUICKLY BUILD INTO THE REGION BY LATE FRIDAY AND
TEMPERATURES WILL HOVER IN THE 20S MOST OF THE DAY UNDER THE
INFLUENCE OF MODEST COLD ADVECTION.
&&
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
HIGH PRESSURE AT THE SURFACE AND UPPER RIDGING ALOFT WILL SLIDE
ACROSS MICHIGAN FRIDAY NIGHT THROUGH EARLY SUNDAY...BRINGING CALMER
WEATHER TO THE AREA. WARMER AND MUCH DRIER AIR ALOFT WILL START TO
PUSH IN BY FRIDAY EVENING...EFFECTIVELY LOWERING INVERSION HEIGHTS
AND STRIPPING AWAY ICE NUCLEI...ENDING POTENTIAL FOR LAKE EFFECT
SNOW TO AFFECT THE THUMB. DECREASING CLOUDS AND WINDS FRIDAY NIGHT
OVER THE FRESH SNOWPACK WILL ALLOW FOR GOOD RADIATIONAL
COOLING...AND DID CONTINUE TO UNDERCUT GUIDANCE SLIGHTLY...WITH
FORECAST MINS IN THE SINGLE DIGITS TO LOW TEENS ACROSS THE AREA.
MODELS START TO SHOW A STRONGER SURGE OF WARMER AIR ARRIVING BETWEEN
925-850MB SATURDAY NIGHT...HOWEVER SNOWPACK AND STRONG SUBSIDENCE
INVERSION SHOULD KEEP SURFACE TEMPERATURES COOL AS THE BOUNDARY
LAYERS REMAINS DECOUPLED. ONCE AGAIN...CONTINUED TO UNDERCUT MOS
GUIDANCE VALUES WITH MINS ONLY SLIGHTLY WARMER THAN FRIDAY NIGHT.
ENERGY NOW OFF THE PACIFIC NORTHWEST COAST WILL MAKE ITS WAY INTO
THE CENTRAL PLAINS ON SUNDAY AND THEN ACROSS THE GREAT LAKES MONDAY.
STRONG UPPER DIFFLUENCE AND UPPER HEIGHTS FALLS LEE OF THE ROCKIES
WILL SPIN UP A FAIRLY STRONG LOW PRESSURE SYSTEM. LATEST CONSENSUS
FROM MEDIUM-RANGE MODELS TRACKS THE SURFACE LOW ACROSS NORTHERN
MICHIGAN MONDAY. 50 KT LOW LEVEL JET PRECEDING THE SYSTEM WILL FEED
WARMTH AND MOISTURE (PW AROUND 0.8 INCHES) UP INTO LOWER MICHIGAN
STARTING SUNDAY AFTERNOON. IT APPEARS MOST PRECIPITATION WILL HOLD
OFF UNTIL VERY LATE IN THE DAY AND OVERNIGHT WHEN STRONGER
ISENTROPIC ASCENT AND UPPER DIVERGENCE WILL OVERSPREAD THE AREA.
STRONGER FORCING SHOULD ALSO COINCIDE WITH WARMING SURFACE
TEMPERATURES PER LATEST TRENDS IN THE EURO AND GFS...AND EXPECT
MOSTLY RAIN TO FALL OUT OF THIS SYSTEM. COLD FRONT WILL PUSH THROUGH
THE AREA EARLY MONDAY...CHANGING PRECIPITATION TO SNOW. STRONG DRY
SLOT PRECEDING THE FRONT IN ADDITION TO DRIER AIR ALOFT STRIPPING
AWAY ICE NUCLEI BEHIND THE FRONT WILL KEEP POTENTIAL FOR SNOW
ACCUMULATIONS LOW.
NORTHWEST FLOW AND PATTERN OF VERY WEAK CLIPPER SYSTEMS THEN LOOKS
TO BECOME ESTABLISHED TUESDAY THROUGH THURSDAY. LATEST EURO AND GFS
HINT AT A STRONGER SYSTEM WORKING ACROSS THE GREAT LAKES LATE ON
THURSDAY...BUT MODEL TO MODEL AND RUN TO RUN CONSISTENCY HAS BEEN
POOR AND WILL LEAVE MENTION OUT OF FORECAST FOR NOW. EARLIER SYSTEM
THE GFS HAD ADVERTISED CLIPPING THE SOUTHERN PORTION OF MICHIGAN
MID-WEEK NOW LOOKS TO TRACK FURTHER SOUTH AS UPPER LEVEL ENERGY
DIVES FURTHER INTO THE U.S. FROM CANADA.
&&
.MARINE...
A LOW PRESSURE SYSTEM WILL STRENGTHEN AS IT TRACKS ACROSS THE
SOUTHERN GREAT LAKES THIS EVENING AND TONIGHT. THIS SYSTEM WILL
CONTINUE EASTWARD EVENTUALLY BEING ABSORBED BY A STRONGER NOREASTER
ALONG THE ATLANTIC COAST FRIDAY NIGHT. THE GRADIENT WILL TIGHTEN
OVERNIGHT AS EASTERLY WINDS INCREASE AND BACK TO THE NORTHEAST.
WINDS WILL INCREASE TO AROUND 25 KNOTS SUSTAINED OVERNIGHT
NECESSITATING BRISK WIND ADVISORIES FOR ALL NEARSHORE ZONES. THE
EXCEPTION WILL BE SAGINAW BAY WHERE A GALE WARNING HAS BEEN ISSUED
AS WINDS FUNNEL DOWN THE BAY WITH THE FAVORABLE NORTHEAST FETCH.
SOME FREEZING SPRAY WILL BE POSSIBLE ACROSS NORTHERN LAKE HURON WITH
THE COOLER TEMPERATURES AND SLIGHTLY STRONGER FLOW TONIGHT...BUT
INTENSITY AND DURATION SHOULD STAY BELOW WARNING CRITERIA. AFTER
HIGH PRESSURE RETURNS TO THE REGION FOR MUCH OF THE WEEKEND...THE
NEXT LOW PRESSURE SYSTEM WILL TARGET THE REGION SUNDAY NIGHT.
&&
.AVIATION...ISSUED 1250 PM EST THU FEB 7 2013
//DISCUSSION...
LOW PRESSURE SYSTEM TRACKING ACROSS THE MI/OH BORDER WILL BRING
DETERIORATING CONDITIONS TO ALL OF SE MI TONIGHT. INITIAL DROP TO
VSBY/CIGS WILL BE AT MBS WHERE LIGHT SNOW SHOWERS WILL BEGIN THIS
AFTERNOON...SPREADING SE WITH TIME THROUGH THIS EVENING. SHORTLY
AFTER MIDNIGHT INTENSITIES WILL INCREASE AND THE HEAVIEST SNOW WILL
BEGIN TO FALL BRINGING IFR CONDITIONS. SNOW SHOWERS WILL TAPER OFF
THROUGH THE MORNING HOURS ON FRIDAY. FREEZING RAIN OR SLEET WILL BE
POSSIBLE AT THE ONSET FOR THE DETROIT METRO AREA...CHANGING TO SNOW
WHEN THE DEEPER MOISTURE ARRIVES.
FOR DTW...DRY AIR WILL PRODUCE VFR CONDITION THROUGH THIS AFTERNOON
BEFORE TURNING TO IFR OVERNIGHT. WARM TEMPERATURES IN THE LOW LEVELS
WILL LIKELY PRODUCE A PERIOD OF FREEZING RAIN OR SLEET AT THE
ONSET OF PRECIPITATION TONIGHT WHICH WILL CHANGE TO SNOW AS
INCREASED SATURATION COOLS THE AIRMASS BRINGING SNOW TO THE METRO
AREA. SNOW WILL FALL HEAVY AT TIMES BETWEEN ABOUT 06-12Z TONIGHT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE OF CEILINGS 5000 FEET OR LOWER AFTER 00Z THIS
EVENING.
* MODERATE CONFIDENCE OF VISIBILITIES AT OR BELOW 1/2 MILE IN SNOW
AFTER 06Z TONIGHT.
* MODERATE CONFIDENCE IN PRECIPITATION STARTING OFF AS FREEZING RAIN
OR SLEET AROUND 03Z BEFORE CHANGING TO SNOW AROUND 06Z.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING...MIZ047-MIZ048-MIZ053...UNTIL 10 AM FRIDAY.
WINTER STORM WARNING...MIZ049-MIZ054-MIZ055-MIZ063...FROM 7 PM
THURSDAY TO NOON FRIDAY.
WINTER WEATHER ADVISORY...MIZ060-MIZ061-MIZ062-MIZ068-MIZ069-
MIZ070...FROM 7 PM THURSDAY TO NOON FRIDAY.
WINTER WEATHER ADVISORY...MIZ075-MIZ076-MIZ082-MIZ083...FROM 9 PM
THURSDAY TO NOON FRIDAY.
LAKE HURON...
GALE WARNING...SAGINAW BAY...FROM 1 AM FRIDAY TO 1 PM FRIDAY.
BRISK WIND ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON...FROM 10 PM THURSDAY TO 10 PM FRIDAY.
WINTER STORM WARNING...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR
BEACH...FROM 7 PM THURSDAY TO NOON FRIDAY.
LAKE ST CLAIR...
BRISK WIND ADVISORY...FROM 10 AM FRIDAY TO 10 PM FRIDAY.
MI WATERS OF LAKE ERIE...
BRISK WIND ADVISORY...FROM 10 AM FRIDAY TO 10 PM FRIDAY.
&&
$$
SHORT TERM...MANN
LONG TERM....HLO
MARINE.......DRK
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
232 PM CST THU FEB 7 2013
.DISCUSSION...
THE MAIN FORECAST ISSUE IS OBVIOUSLY THE POTENTIAL FOR A
SIGNIFICANT WINTER STORM ACROSS THE AREA OVER THE SECOND HALF OF
THE WEEKEND. LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES
SHOW THE FEATURE OF INTEREST MOVING INTO THE WEST COAST AT THE
CURRENT TIME. THE OTHER FEATURES OF INTEREST IN THE BIG PICTURE
ARE THE UPPER WAVE CURRENTLY MOVING THROUGH OUR AREA... WHICH IS
HELPING TO GENERATE A SWATH OF PCPN OFF TO OUR SOUTHEAST... AND
THE SOUTHERN STREAM WAVE MOVING ALONG THE GULF COAST. THESE TWO
UPPER WAVES WILL PHASE OFF THE MID-ATLANTIC COAST AND CREATE A
BLOCKBUSTER OF A WINTER STORM FOR FOLKS IN NEW ENGLAND OVER THE
NEXT 48 HOURS. THE EVOLUTION OF THAT SYSTEM WILL IMPACT HOW THE
WESTERN SHORTWAVE BEHAVES AS IT EJECTS NORTHEAST INTO OUR AREA
OVER THE LATTER HALF OF THE WEEKEND. THE DEGREE TO WHICH THE
EASTERN STORM BOTTLES UP THE FLOW WILL HELP DICTATE THE TRACK AND
AMPLITUDE OF THE UPPER PATTERN AHEAD OF OUR SYSTEM... WHICH IS
LIKELY PART OF WHY WE/RE STILL SEEING A SIGNIFICANT AMOUNT OF
SPREAD IN THE GUIDANCE AS TO HOW THINGS WILL UNFOLD ACROSS OUR
AREA. THE NAM AND GFS ARE FARTHEST WEST... ALONG WITH THE SREF...
WHILE THE ECMWF... GEM... AND FIM ARE FARTHER EAST. AT THIS
POINT... THE CONSENSUS OF THE GUIDANCE IS FAIRLY CLOSE TO THE
ECMWF EVOLUTION... SO WILL STICK SOMEWHAT CLOSE TO THAT WHILE
ALLOWING FOR A BIT MORE WARMING IN THE LOW LEVEL THERMAL PROFILES
IN ACCORDANCE WITH WHAT THE NAM AND GFS SUGGEST TO SOME EXTENT.
THIS WOULD CONTINUE TO SUGGEST A MIXED PCPN EVENT FOR A GOOD PART
OF THE AREA... WITH THE NORTH AND NORTHWEST PORTION OF THE AREA
HAVING THE GREATEST LIKELIHOOD OF REMAINING ALL SNOW. WITH THAT IN
MIND... WILL BE ISSUING A WINTER STORM WATCH THAT INCLUDES THE
NORTHERN AND WESTERN PORTION OF THE AREA FROM SATURDAY NIGHT
THROUGH SUNDAY NIGHT. IT IS POSSIBLE THAT THE WATCH MAY NEED TO BE
EXTENDED SOUTH/EAST IN AREA DEPENDING UPON HOW EXPECTATIONS
EVOLVE... BUT FOR NOW DECIDED TO FOCUS ON WHERE CONFIDENCE IS
HIGHEST THAT 6-8 INCHES OR MORE OF SNOW WILL OCCUR... ALONG WITH
STRONG WINDS.
IN THE SHORTER TERM... LINGERING VERY LIGHT FREEZING DRIZZLE
CURRENTLY ACROSS THE AREA SHOULD MIX WITH SOME SNOWFLAKES AS WE
SEE A BIT OF SEEDING FROM DEEPER MOISTURE ASSOCIATED WITH THE
UPPER WAVE MOVING ACROSS THE AREA... AND ALL OF THIS ACTIVITY
SHOULD EXIT QUICKLY TO THE EAST THIS EVENING AS WE GET ONTO THE
BACKSIDE OF THE WAVE AND SEE SOME SUBSIDENCE SPREAD OVER THE AREA.
HIGH PRESSURE WILL REIGN FRIDAY THROUGH FRIDAY NIGHT... ALLOWING
FOR FAIR AND DRY CONDITIONS. RETURN FLOW WILL SETUP BY SATURDAY
MORNING... THEN REMAIN IN PLACE INTO SATURDAY NIGHT... ALLOWING
FOR GOOD MOISTURE RETURN AHEAD OF THE SYSTEM WHICH WILL EXIT THE
ROCKIES SATURDAY EVENING AND MOVE NORTHEAST INTO NEBRASKA BY
SUNDAY MORNING. GOOD ISENTROPIC ASCENT IS PROGGED ALONG THE
EASTERN PERIPHERY OF THE INVERTED TROUGH AHEAD OF THE SURFACE
LOW... AND UPPER DIVERGENCE IS EXPECTED TO INCREASE DRAMATICALLY
ACROSS THE CWFA BY SUNDAY AFTERNOON AND THE UPPER FLOW AMPLIFIES
AND DIFFLUENCE INCREASES MARKEDLY IN THE LEFT EXIT REGION OF THE
APPROACHING JET. THESE THINGS SUPPORT DEVELOPMENT AND ENHANCEMENT
OF PCPN ACROSS THE AREA ON SUNDAY WITH THIS INITIAL SURGE OF WARM
ADVECTION AND DEEP MOISTURE INTO THE AREA. PCPN-TYPE CONTINUES TO
BE THE PRIMARY ISSUE THAT WILL MITIGATE SNOWFALL POTENTIAL... AND
THERE IS GOOD AGREEMENT THAT WE SHOULD SEE SUFFICIENT WARM AIR
MOVE IN ALOFT TO CHANGE THINGS TO SLEET AND PERHAPS SOME FREEZING
RAIN FOR A TIME ACROSS THE SOUTHERN PORTION OF THE AREA... BEFORE
GOING OVER TO MAINLY RAIN FOR AT LEAST PART OF THE DAY. HOWEVER...
HEIGHTS CRASH QUICKLY BY SUNDAY EVENING AS THE UPPER LOW MOVES
INTO THE AREA... WHICH ALONG WITH DYNAMIC COOLING FROM SUSTAINED
UPWARD MOTION COULD HELP TO CHANGE THINGS BACK TO SNOW FAIRLY
QUICKLY DEPENDING UPON WHETHER THE AMOUNT OF WARM AIR WHICH MOVES
IN IS AS ROBUST AS THE GFS SUGGESTS OR CLOSER TO THE ECMWF AND
FIM. FOR NOW... KEPT THINGS ALL SNOW ACROSS THE NORTH AND
NORTHWEST... AND ALLOWED FOR MIXED PCPN UP THROUGH THE SOUTHERN
COUNTIES AND INTO THE NORTHERN TWIN CITIES METRO. THAT BEING
SAID... WITH PCPN TOTALS OF OVER SIX TENTHS OF AN INCH EXPECTED
OVER MUCH OF THE AREA... AND PERHAPS SOME CLOSE TO AN INCH... ANY
PERIOD OF SNOW COULD PUT DOWN DECENT ACCUMULATIONS. EXPECT
LOCATIONS THAT REMAIN ALL SNOW TO WIND UP BETWEEN 6 AND 10 FOR THE
MOST PART... ALTHOUGH LOCALLY HIGHER AMOUNTS COULD OCCUR DEPENDING
ON RATIOS... WHILE AMOUNTS WILL DECREASE QUICKLY AS ONE MOVES INTO
AREAS WHERE A GREATER PORTION OF THE PCPN IS OF MIXED-TYPE AND/OR
RAIN. AT THIS POINT... THE BEST GUESS FOR THE TWIN CITIES WOULD BE
FOR TOTAL AMOUNTS OF NEAR 6 INCHES... WITH THE NORTH AND NORTHWEST
SUBURBS SEEING THE GREATEST... BUT THAT COULD CERTAINLY CHANGE
DEPENDING UPON HOW THE STORM TRACK PANS OUT AND THE CHARACTER OF
WARM ADVECTION AHEAD OF IT. NEEDLESS TO SAY... THE SITUATION WILL
REQUIRE CONTINUED MONITORING... WITH UPDATES AND CHANGES LIKELY AS
WE HEAD THROUGH THE NEXT DAY OR TWO.
SOME SNOW SHOWERS CAN BE EXPECTED IN THE CYCLONIC FLOW ON THE
BACKSIDE OF THE SYSTEM THROUGH THE DAY ON MONDAY... WITH THINGS
DRYING OUT FOR GOOD ONCE HIGH PRESSURE WORKS IN MONDAY NIGHT AND
TUESDAY. BENIGN WEATHER THEN LOOKS TO PREDOMINATE THROUGH THE
BALANCE OF THE FORECAST PERIOD. AN ALBERTA CLIPPER COULD IMPACT
THE AREA BY THURSDAY... ALTHOUGH THERE ARE SOME DEFINITE TIMING
AND PLACEMENT DIFFERENCES BETWEEN THE GFS... ECMWF... AND THEIR
RESPECTIVE ENSEMBLES WITH RESPECT TO THAT... SO KEPT THING DRY
AFTER MONDAY FOR NOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
/ISSUED 1211 PM CST THU FEB 7 2013/
AFTER ABOUT 6 STRAIGHT HOURS OF NEARLY SATURATED CONDITIONS...FZDZ
FINALLY MADE AN APPEARANCE AROUND 10 AM...WHICH WAS ACCOMPANIED BY
A BLOOM IN LOW REFLECTIVITIES ON RADAR. STILL SEEING THAT RADAR
BLOOM AT 18Z...BUT DZ HAS BEEN LIGHT...IT IS BARELY PERCEPTIBLE
AND IS OF MINIMUM IMPACT...SO LEFT MENTION OUT OF THESE TAFS. OF
BIGGER CONCERN FOR THE REST OF TONIGHT INTO TOMORROW IS THE SEA OF
STRATUS THAT IS IN PLACE FROM MICHIGAN BACK TO THE WRN DAKOTAS AND
NE NEB. GIVEN THE EXTENT OF STRATUS...WENT MORE PESSIMISTIC WITH
STRATUS THROUGH TONIGHT. CURRENT TREND ACROSS CENTRAL MN SHOWS
MVFR CIGS MAKING INROADS SOUTH...WITH MSP AND WI TERMINALS LIKELY
GOING MVFR BY 20Z...WITH A BIT OF A LONGER DELAY SOUTHWEST TOWARD
RWF. AS SFC RIDGING AND UPPER SUBSIDENCE MOVE OVERHEAD
TONIGHT...EXPECT CIGS TO RETREAT BACK TO IFR LEVELS...WITH
MVFR/IFR VSBYS RETURNING AS WELL. DO EXPECT SOME CLEARING TONIGHT
OVER NE MN CLOSER TO CENTER OF HIGH PRES...SO WILL HAVE TO WATCH
HOW FAR SW INTO CENTRAL MN THAT CAN MAKE IT TONIGHT. CONFIDENCE IN
TIMING OF IMPROVEMENTS FRIDAY MORNING NOT VERY HIGH...JUST WANTED
TO TREND CIGS REMAINING LONGER WITH THESE TAFS.
KMSP...GIVEN EXTENT OF STRATUS...CONFIDENT IN CIGS REMAINING IN
PLACE THROUGH THE EVENING PUSH...WITH HEIGHTS GOING BACK TO
BETWEEN 010 AND 017. CONFIDENCE STARTS TO DIMINISH OVERNIGHT WITH
POTENTIAL FOR SOME CLEARING WORKING SOUTH WITH THE RIDGE...BUT
WITH STRATUS IN PLACE...PLAYED THINGS THE PESSIMISTIC ROUTE FOR
NOW. ALSO BROUGHT BACK MVFR VIS...BUT CONFIDENCE NOT AS HIGH WITH
THAT. AT SOME POINT IN THE MORNING AS MSP GETS ON THE WEST SIDE OF
THE RIDGE...VFR CONDITIONS WILL RETURN ALONG WITH SOUTHEAST
WINDS...BIG QUESTION REMAINS WHEN.
/OUTLOOK FOR KMSP/
SAT...VFR. IFR DEVELOPING LATE WITH PRECIP MIX. WINDS SSE 10G15KTS.
SUN...IFR WITH RA/SN. SIGNIFICANT IMPACTS POSSIBLE. ESE AT 15G20KTS.
MON...IFR WITH SN IN MORNING...MVFR AFTERNOON. WINDS WNW 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH LATE SUNDAY
NIGHT FOR BENTON-CHIPPEWA-DOUGLAS-ISANTI-KANABEC-KANDIYOHI-
LAC QUI PARLE-MEEKER-MILLE LACS-MORRISON-POPE-SHERBURNE-
STEARNS-STEVENS-SWIFT-TODD-YELLOW MEDICINE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
303 PM CST Thu Feb 7 2013
.DISCUSSION...
Tonight through Saturday afternoon...
The main concern for tonight will be the extent and longevity of a
stratus shield which has been sinking southward this afternoon.
Local near-surface moisture from recent rainfall and a low-level
wind trajectory off the existing stratus will continue through at
least 09z, which may support its southward expansion. However, model
agreement is poor beyond 00z and some erosion has been evident along
the far western and southwestern edge this afternoon, so the
forecast remains uncertain. Hourly temperature trends and forecast
low temperatures tonight will need to be monitored, especially if
stratus clears quickly.
After clearing occurs Friday morning, clear skies and return flow
developing across the eastern Plains will allow temperatures to warm
for Friday and Saturday. Saturday afternoon may be a bit breezy as
deepening low pressure begins to eject out into the High Plains, but
any precipitation associated with the approaching system should hold
off until at least late Saturday afternoon or evening.
Saturday evening through Sunday night...
Warm air advection and moisture transport ahead of the deepening
system over the southern High Plains may allow showers and isolated
thunderstorms to develop by late Saturday afternoon. As a warm front
lifts through the CWA on Saturday night, thunderstorms will become
more likely and will spread northeastward across the region. A few
strong storms may be possible Saturday night; however, the limiting
factor will be the amount of moisture that can be transported into
the region between today`s and Saturday night`s systems. Models have
backed off a bit on low-level moisture increases during the night,
bringing 45 to possibly 50 degree dewpoints into the southeastern
CWA, but keeping the better moisture to the south and east. Have
also kept precipitation amounts on the conservative side as a result
of the moisture availability, although have trended higher that
blended model guidance products.
Thunderstorms will likely lose intensity on Sunday as the warm front
pushes through the region, while an intrusion of dry air works to
precipitation chances in advance of the cold front. A few breaks of
sunshine and strong warm air advection in the dry slot could help
central and southern portions of the CWA warm to near 60 on Sunday,
but this warming will depend on the amount of clearing that is
possible before the surface cold front pushes through. Rain chances
should end altogether by 00z Monday.
Monday through Thursday...
Quieter conditions are expected next week, with gradually warming
temperatures and little to no chance of precipitation. A system may
skirt the Gulf Coast on Monday night into Tuesday morning, but model
consensus keeps it far enough south not to impact any portion of the
forecast area. Ridging will briefly build over the central Plains by
Wednesday evening, allowing temperatures to rise back to above
normal values for middle to late next week, before colder conditions
become possible late Thursday.
Laflin
&&
.AVIATION...
For the 18Z TAFs...back edge of light rain and low clouds is
currently clearing the KC area, and will make continued eastward
progress toward IRK and COU through the afternoon. Rapid improvement
to VFR is expected shortly after the rain ends.
Currently watching a very large area of MVFR/IFR cigs advancing
southeastward out of the Dakotas into eastern Nebraska. Most models
erode this cloud cover from west to east before it is able to impact
the KC terminals overnight. However, the RAP model, which has been
the better performer is similar scenarios this winter, brings thick
IFR clouds into all of the region overnight. Given all the remnant ground
moisture and falling temps overnight, and the extent of the cloud
cover on current satellite imagery, decided to go with the RAP with
widespread IFR restrictions tonight. If clouds do not develop then
areas of BR/FG will be a concern instead, especially along and north
of the STJ/IRK corridor.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1138 AM CST Thu Feb 7 2013
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Range (Today through Saturday)...`
Shortwave trough crossing the Continental Divide will track east
across KS/OK this morning and interact with a cold front that
currently stretches from central IA through the TX Panhandle. Modest
southerly low level jet plus generous theta-e advection has resulted
in precipitable water values well above seasonal values. Initial
overnight scattered convection affected areas north of the MO River
and has come and gone. However, an expanding area of showers and
isolated thunderstorms over central and eastern KS will overspread
much of the CWA this morning. Far northwest MO and northeast KS
could very well end up missing most of the rain today. Latest NAM
and RAP qpf have performed best overnight and look like they have
locked into the current radar trend.
The cold front will push southeast and through the CWA, reaching
central MO by mid afternoon. There will be some post frontal rain so
the passage of the front will not herald the end of the rain. That
should come several hours after passage of the front. Temperatures
will initially fall with the passage of the front but mid/late
afternoon clearing across the northwest third of the CWA should
allow a bit of a recovery in temperatures.
High pressure building into the region through Friday will bring
cooler temperatures but still end up being above normal. The high
pressure will head east of the CWA on Saturday as an upper level
ridge progresses east through the Central Plains and MO. The
resulting warm air advection will bring warmer temperatures plus an
increase in clouds. GFS and ECMWF have started to bring in the next
wave of precipitation a bit faster than earlier forecast and could
very well see scattered showers move into east central KS and far
west central MO late in the day. The initial wave of showers will
be elevated and won`t be surprised if the models continue trending
faster in bringing in the warm advection showers.
MJ
Medium Range (Saturday night through Thursday)...
There are two systems of concern in the medium range. The first is a
system that models agree will affect the entire forecast area
Saturday night into Sunday. The second system will move south of the
area Tuesday night bringing the chance for precipitation to the
extreme southern portion of the forecast area.
Models continue to be in good agreement that a closed upper low will
move out of the Great Basin on Saturday night and into the central
Plains. Surface cyclogenesis will also occur over eastern Colorado
Saturday night with a surface low developing and moving into central
Nebraska overnight. A cold front will stretch southward from the
surface low into the southern Plains. Strong warm air advection out
ahead of this front will spread Gulf moisture northward and showers
and thunderstorms will develop from west to east over the forecast
area. The upper level low and attendant surface low will move well
north of the area on Sunday into the Upper Midwest. The GFS is
slightly faster and a little further north than the EC but still in
good agreement. In any case, the local area will remain in the warm
sector and as the cold front moves through the area on Sunday and
showers and thunderstorms will continue to be likely over the
forecast area. Sunday night this system moves into the western Great
Lakes and the cold front pulls east of the forecast area.
Temperatures will be warm on Sunday ahead of the front with highs in
the 50s to near 60. Although there is no really cold air behind this
front, temperatures will be markedly cooler on Monday with highs in
the mid 30s to mid 40s.
The next system of interest will be a upper trough that digs down
the west coast on Monday and develops a closed low over the
southwestern CONUS on Tuesday. The GFS is further north with the
track of the closed low than the EC as it moves into the southern
Plains. The GFS would bring the upper low through Oklahoma and into
southern Missouri Tuesday night bringing snow to the southern half
of the forecast area. The EC would take the upper low across Texas
and into Arkansas leaving the forecast area dry. Opted to keep the
middle of the road solution offered by the initialization and keep
slight chance pops for light snow across the southern zones on
Tuesday night. Temperatures Tuesday will range into the mid 30s to
lower 40s. A warming trend with dry conditions will then be expected
through mid week with highs on Thursday in the 40s.
73
&&
.AVIATION...
For the 18Z TAFs...back edge of light rain and low clouds is
currently clearing the KC area, and will make continued eastward
progress toward IRK and COU through the afternoon. Rapid improvement
to VFR is expected shortly after the rain ends.
Currently watching a very large area of MVFR/IFR cigs advancing
southeastward out of the Dakotas into eastern Nebraska. Most models
erode this cloud cover from west to east before it is able to impact
the KC terminals overnight. However, the RAP model, which has been
the better performer is similar scenarios this winter, brings thick
IFR clouds into all of the region overnight. Given all the remnant ground
moisture and falling temps overnight, and the extent of the cloud
cover on current satellite imagery, decided to go with the RAP with
widespread IFR restrictions tonight. If clouds do not develop then
areas of BR/FG will be a concern instead, especially along and north
of the STJ/IRK corridor.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
958 AM MST THU FEB 7 2013
.SHORT TERM...VALID FOR TDY AND FRI...
A MINOR UPDATE WAS MADE TO THE CLOUD COVER FORECAST FOR TODAY SUCH
THAT AT LEAST PARTLY SUNNY WORDING IS ADVERTISED FOR MUCH OF SOUTH
CENTRAL AND PARTS OF SOUTHEASTERN MT. THIS CHANGE WAS BASED MAINLY
ON MID-MORNING SATELLITE IMAGES...WHICH SHOW INCREASING HIGH-LEVEL
CLOUDS OVER THE REGION. OTHERWISE...THE PRIMARY FORECAST CHALLENGE
TODAY WILL BE HIGH TEMPERATURES GIVEN WARM AIR ADVECTION ALOFT AND
RELATIVELY WEAK BOUNDARY LAYER FLOW AND MIXING. FORECAST SOUNDINGS
FROM THE 12 UTC NAM AND RAP SUGGEST MIXING WILL BE LIMITED TO NEAR
1000 FT AGL OVER MUCH OF THE AREA /SAVE FOR LIVINGSTON...WHERE THE
MIXING DEPTH IS SIMULATED A BIT DEEPER TO 2000 FT AGL/. WE BELIEVE
THIS WILL LIMIT HIGHS FROM REACHING THE FULL POTENTIAL OF THE WARM
AIR MASS. SINCE OUR FORECAST IS CLOSE TO THE BIAS-CORRECTED MULTI-
MODEL CONSENSUS...WE DECIDED TO LEAVE IT ALONE FOR NOW. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
A PACIFIC TROUGH CURRENTLY SEEN ON WV IMAGERY ENTERING THE PACIFIC
NORTHWEST WILL CUTOFF AND TRACK OVER THE GREAT BASIN BY SATURDAY
MORNING. THE EXTENDED FORECAST BEGINS HERE...WITH THE CUTOFF
PACIFIC LOW BRINGING COOLER WEATHER AND A PERIOD OF ACTIVE WEATHER
TO THE FORECAST AREA. CURRENT MODEL TRACKS OF THE LOW KEEP THE
BULK OF THE FORCING SOUTH OF THE FORECAST AREA...INTO WYOMING.
HOWEVER...THERE HAS BEEN A MINOR NORTHWARD TREND IN THE TRACK OF
THE LOW...WHICH GIVES OUR SOUTHERN ZONES A BETTER CHANCE OF SEEING
SOME PRECIPITATION ON SATURDAY WITH THIS SYSTEM. AS THE LOW SHIFTS
INTO THE DAKOTAS ON SUNDAY...NORTHERLY FLOW IS ESTABLISHED OVER
THE FORECAST AREA...AND A SECONDARY VORTICITY MAXIMUM IS ALLOWED
TO DIVE SOUTH ACROSS THE FORECAST AREA ON THE BACK SIDE OF THE
MEAN TROUGH. THIS SECONDARY VORT MAX WILL HELP TO PUSH A STRONGER
COLD FRONT ACROSS THE FORECAST AREA ON SUNDAY. THIS WILL GIVE THE
REST OF THE FORECAST AREA A BETTER CHANCE OF PRECIPITATION BEHIND
THE COLD FRONT.
MONDAY WILL REMAIN A COOLER DAY AS THE AMPLIFIED TROUGH IS SLOW TO
PUSH EAST...HOWEVER...THIS WILL ALSO BE A DRY DAY AS THE FORCING
WITH THE WAVE EXITS THE AREA. NORTHWESTERLY FLOW IS REESTABLISHED
ACROSS THE FORECAST AREA BY TUESDAY AS THE MEAN RIDGE AXIS SLOWLY
SLIDES EAST. DOWNSLOPE WINDS WILL RETURN TUESDAY AND
WEDNESDAY...BRINGING CONTINUED WARMING AND DRY CONDITIONS. EXPECT
ANOTHER WINDY PERIOD ALONG THE FRONT RANGE FROM LIVINGSTON TO BIG
TIMBER TO NYE. THE WINDS WILL HELP TO KEEP NIGHTTIME TEMPERATURES
MILDER IN THESE LOCATIONS...WITH DAY TIME HIGHES EXPECTED INTO THE
40S. ANOTHER PACIFIC TROUGH APPROACHES THE FORECAST AREA BY NEXT
THURSDAY...BRINGING THE NEXT BEST CHANCE OF COOLER TEMPERATURES
AND PRECIPITATION.
CHURCH
&&
.AVIATION...
EXPECT VFR CONDITIONS THIS AFTERNOON THROUGH FRI MORNING.
LOCALIZED MOUNTAIN OBSCURATIONS WILL BE POSSIBLE OVER THE
CRAZYS...BEARTOOTHS AND ABSAROKAS LATE TONIGHT THROUGH FRI
MORNING. GUSTY SOUTHWEST SURFACE WINDS...WITH GUSTS TO 25 KT...WILL
OCCUR OVER KLVM THIS AFTERNOON AND EVENING. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 048 025/044 021/037 024/031 017/035 025/043 026/046
0/B 01/B 11/B 22/J 11/B 11/B 11/B
LVM 046 023/041 017/033 021/027 013/034 028/041 027/044
0/N 02/O 22/J 32/J 21/B 11/N 11/B
HDN 046 018/042 017/036 022/030 014/034 021/042 022/045
0/B 00/B 12/J 23/J 21/B 11/B 11/B
MLS 047 022/042 017/034 021/029 014/032 022/039 024/041
0/B 00/B 10/B 23/J 21/B 11/B 11/B
4BQ 049 023/044 020/034 020/029 015/030 021/039 023/042
0/U 00/B 11/B 23/J 21/B 11/U 11/B
BHK 044 019/042 013/031 017/027 011/026 018/034 021/036
0/U 00/B 00/B 23/J 20/B 01/B 11/B
SHR 044 019/041 017/032 016/027 011/029 016/039 018/042
0/U 00/B 53/J 34/J 21/B 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1138 AM CST THU FEB 7 2013
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
EXTENSIVE STRATUS DECK...WITH SOME VISIBILITY RESTRICTIONS...WILL
CONTINUE TO SPREAD OVER THE TAF SITES THROUGH THE DAY AND
POSSIBLY INTO THE OVERNIGHT. WILL CONTINUE WITH IFR CONDITIONS FOR
THE TAF CYCLE. KLNK MAY BE THE ONLY EXCEPTION AS THEY REMAIN ON
THE EDGE OF THE STRATUS DECK.
KERN
&&
.PREV DISCUSSION... /ISSUED 355 AM CST THU FEB 7 2013/
DISCUSSION...
CHALLENGING FORECAST TODAY WITH STRATUS SPREADING SOUTH AND
CAUSING POTENTIAL PROBLEMS WITH TEMPERATURE FORECAST...AND
CHALLENGING PRECIPITATION FORECAST FOR WEEKEND WITH STRONG LOW
MOVING THROUGH PLAINS.
CURRENT PATTERN AT THE SURFACE CONSISTED OF A WEAK COLD FRONT
THAT WAS ANALYZED AT 09Z ALMOST THROUGH THE SOUTHEAST CORNER OF
THE FORECAST AREA. WELL BEHIND THE FRONT IN SOUTH DAKOTA WAS AN
EXTENSIVE AREA OF LOW STRATUS...MOVING SOUTH AT AROUND 15 KNOTS.
SHORT TERM MODELS SHOW LITTLE AGREEMENT ON THE EVOLUTION OF THIS
AREA OF STRATUS. GENERALLY THE NAM AND GFS BRING IT INTO THE
FORECAST AREA BUT SUGGEST IT WILL ERODE BY AFTERNOON. HOWEVER THE
HIGHER RESOLUTION HRRR AND RAP ARE MUCH MORE PESSIMISTIC AND PUSH
THE STRATUS AS FAR SOUTH AS THE PLATTE RIVER BY 17Z AND SHOW IT
REMAINING. THIS OF COURSE HAS BIG IMPLICATIONS FOR THE TEMPERATURE
FORECAST. AT THIS TIME WE ARE MORE COMFORTABLE WITH A SOLUTION
CLOSER TO THE HRRR/RAP ESPECIALLY IN NORTHEAST NEBRASKA. THUS HAVE
LOWERED HIGH TEMPERATURES IN NORTHEAST NEBRASKA AND AND KEPT
CLOUDY WORDING THROUGH MUCH OF THE DAY.
TEMPERATURE/CLOUD UNCERTAINTY IS GREATEST FOR LOCATIONS ALONG
INTERSTATE 80 WHERE THE HRRR/RAP SHOW THE STRATUS JUST
APPROACHING. THIS AREA WILL NEED TO BE WATCHED THIS MORNING TO
MONITOR THE SOUTHWARD EXTENT OF THE CLOUD DECK AND THE NEW RUNS OF
THE HRRR AND RAP.
ON FRIDAY THE ATTENTION TURNS TO THE UPPER PATTERN PROGRESSING WITH
A STRONG UPPER LOW MOVING FROM THE WEST THROUGH THE ROCKIES AND
TAKING AIM ON THE PLAINS FOR THE WEEKEND. MODELS AGREE ON LEE SIDE
CYCLOGENESIS BY FRIDAY AFTERNOON AND SOUTH WINDS INCREASING BY
FRIDAY NIGHT. FRIDAY WILL BE DRY...WITH TEMPERATURES MILD AGAIN.
MOST MODELS SHOW DECENT AGREEMENT WITH THE UPPER LOW MOVING OUT OF
COLORADO SATURDAY NIGHT. SOUTHERLY 850 WINDS ARE PROGGED AS HIGH
AS 60 KNOTS OVER THE FORECAST AREA SATURDAY NIGHT AND SUNDAY
MORNING. LOW TEMPERATURES SATURDAY NIGHT WILL BE MILD...WITH
HUMIDITY INCREASING. VERTICAL MOTION AND MOISTURE WILL BE
SUFFICIENT TO TRIGGER SCATTERED SHOWERS ESPECIALLY NORTHERN HALF
OF FORECAST AREA. ON SUNDAY MORNING...THE DRY SLOT WILL BE PUSHING
NORTH THROUGH NEBRASKA. THIS PATTERN HAS THE APPEARANCE OF A
SPRING LOW TOPPED/COLD CORE THUNDERSTORM EVENT. TIGHTLY WRAPPED UP
SURFACE LOW IS PROGGED TO MOVE NEAR EASTERN NEBRASKA JUST EAST OF
CLOSED UPPER LOW...WITH MUCAPE VALUES OF 200-400 J/KG ALONG THE
EDGE OF THE DRY SLOT. CURRENTLY HAVE THUNDER MENTIONED IN FORECAST
AND WILL NEED TO MONITOR FOR ADDITIONAL DETAILS.
AS THE LOW MOVES NORTHEAST...COLD AIR MOVES IN WITH PRECIPITATION
CHANGING TO SNOW ESPECIALLY IN NORTHEAST NEBRASKA. SOME SCENARIOS
SUGGEST A FEW INCHES OF SNOW WITH NORTHWEST WINDS GUSTING TO 40
MPH GIVEN THE NORTHWEST 850 WINDS OF 50 KNOTS OVER FAR NORTHEAST
NEBRASKA. FORECAST COVERS THIS BUT WILL CONTINUE TO ADVERTISE THIS
POSSIBLE WINTER WEATHER EVENT IN HWO. MOST MODELS HAVE THE
PRECIPITATION ON SUNDAY ENDING AS THE LOW RAPIDLY MOVES
NORTHEAST...MEANING THE OMAHA-LINCOLN AREAS AND POINTS SOUTH WOULD
SEE LITTLE SNOW.
NIETFELD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
303 PM CST THU FEB 7 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...
THE MAIN CHALLENGE FOR THE SHORT TERM IS FOG AND STRATUS LATE THIS
AFTERNOON INTO FRIDAY.
THUS FAR TODAY...THE HRRR AND RAP HAVE CAPTURED THE STRATUS THE
BEST ACROSS WESTERN AND CENTRAL NORTH DAKOTA...AND WILL FOLLOW
THEIR SOLUTIONS WHICH KEEP THE STRATUS NEARLY INTACT THROUGH THE
NIGHT. GIVEN WEAK MIXING...NO AIRMASS EXCHANGE AND WEAK LOW LEVEL
WARM AIR ADVECTION REINFORCING THE INVERSION THAT IS TRAPPING THE
MOISTURE...ALSO KEPT THE STRATUS IN PLACE THROUGH MUCH OF THE DAY
ON FRIDAY FOR THE CENTRAL AND INTO THE FAR NORTHWEST. DID ISSUE A
DENSE FOG ADVISORY FOR NORTHWEST NORTH DAKOTA EARLIER THIS
AFTERNOON WHICH RUNS THROUGH 03 UTC THIS EVENING. WHILE
VISIBILITIES HAVE INCREASED ABOVE ONE QUARTER OF A MILE...WILL
KEEP THE ADVISORY IN PLACE AS VISIBILITIES ARE EXPECTED TO TREND
DOWN ONCE AGAIN AFTER SUNSET. DID EXPAND THE MENTION OF FOG
THROUGH THE SOUTH CENTRAL INTO FRIDAY MORNING ALONG THE COOL SIDE
OF THE BOUNDARY THAT WAS LOCATED FROM NORTHEAST MONTANA TO
APPROXIMATELY MOBRIDGE. GIVEN THE LACK OF ICE CRYSTALS IN THE
COLUMN AND SATURATION WARMER THAN -10 C...ALSO ADDED PATCHY LIGHT
FREEZING DRIZZLE TO THE AREAS EXPECTED TO BE IMPACTED BY FOG. THE
QUESTION IS WHETHER OR NOT THE DENSE FOG ADVISORY WILL NEED TO
EXPANDED IN TIME AND/OR AREA LATER THIS EVENING. THE UNCERTAINTY
IS IN INCREASING LOW LEVEL MIXING POST 06 UTC WHICH MAY HELP TO
KEEP VISIBILITIES ABOVE ONE QUARTER OF A MILE...BUT...WILL MONITOR
TRENDS THROUGH THE EVENING.
AS STATED ABOVE...DID KEEP THE STRATUS ACROSS MUCH OF CENTRAL AND
INTO THE NORTHWEST THROUGH MUCH OF FRIDAY...AND BEGAN CLEARING
FROM THE NORTHWEST THROUGH THE JAMES RIVER VALLEY LATE IN THE
AFTERNOON AND INTO THE EVENING AS WEAK HIGH PRESSURE BUILDS ACROSS
THE AREA. THAT SAID...FLOW WILL BE WEAK AND WOULD NOT BE SURPRISED
IF THE STRATUS DOES LINGER INTO SATURDAY NIGHT. THUS...DO NOT
HAVE A LOT OF CONFIDENCE IN THE GUIDANCE SUITE OUTSIDE OF THE
HRRR/RAP AS IT HAS NOT HANDLED THE STRATUS WELL THIS AFTERNOON.
.LONG TERM...
LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THE SNOW AND
BLOWING SNOW CHANCES SATURDAY NIGHT THROUGH SUNDAY NIGHT.
FOR DAYTIME SATURDAY...DRY CONDITIONS ARE EXPECTED AS HIGH PRESSURE
PUSHES EAST ACROSS THE CWA WITH THE DEVELOPING STORM SYSTEM OVER THE
SOUTHERN PLAINS. TEMPERATURES ARE FORECAST TO BE NEAR TO SLIGHTLY
ABOVE NORMAL READINGS...FROM THE 20S NORTH TO LOWER 30S SOUTHWEST.
FOR SATURDAY NIGHT THROUGH MONDAY...
THE MODELS CONTINUE TO COME INTO BETTER AGREEMENT WITH RESPECT TO A
LARGE UPPER LEVEL TROUGH AND ATTENDANT SOUTHERN STREAM SURFACE LOW
PRESSURE SYSTEM FORECAST TO IMPACT THE REGION FOR THE LATTER HALF OF
THIS WEEKEND. THE MODELS DEVELOP THE SURFACE LOW NORTHEASTWARD FROM
COLORADO/KANSAS SATURDAY AFTERNOON TO EASTERN NEBRASKA/KANSAS BY
SUNDAY MORNING WITH AN INVERTED TROUGH EXTENDING NORTHEASTWARD
ACROSS THE RED RIVER VALLEY. AT THIS TIME IT APPEARS THAT THE
LEADING EDGE OF THE SNOW FROM THE SYSTEM WOULD REACH SOUTHEASTERN
AND PARTS OF SOUTH CENTRAL NORTH DAKOTA - FROM THE RED RIVER VALLEY
TO THE JAMES RIVER VALLEY IN NORTH DAKOTA TO ROUGHLY SIOUX COUNTY -
LATE SATURDAY NIGHT.
THE MODELS CONTINUE TO DEPICT THE STORM SYSTEM CENTER
DEVELOPING/MOVING TO IOWA/SOUTHERN MINNESOTA BY SUNDAY EVENING...AND
REACHING WISCONSIN AND LAKE SUPERIOR BY MONDAY MORNING. THE MODELS
DEPICT A TROWAL FEATURE WITH THIS SYSTEM AFFECTING MINNESOTA AND THE
EASTERN DAKOTAS SUNDAY AND SUNDAY NIGHT. THE LARGE CLOUD AND
MOISTURE SHIELD ASSOCIATED WITH THIS TROWAL WOULD CONTINUE TO AFFECT
THE EASTERN HALF OF THE STATE...ROUGHLY FROM MINOT/BISMARCK
EASTWARD...THROUGH SUNDAY EVENING...WITH THE TROWAL FEATURE MOVING
EASTWARD ON MONDAY MORNING. THUS SNOW AND BLOWING SNOW WILL IMPACT
CENTRAL NORTH DAKOTA ALL DAY SUNDAY THROUGH MONDAY MORNING.
IN CENTRAL AND WESTERN NORTH DAKOTA: MODERATE TO HEAVY SNOWFALL
AMOUNTS FROM THIS SCENARIO WOULD IMPACT THE JAMES RIVER BASIN THE
MOST...WITH LIGHT SNOW AMOUNTS ALONG A BISMARCK/MINOT LINE.
TEMPERATURES ARE NOT EXPECTED TO BE SUBZERO THROUGH THIS
PERIOD...WITH HIGHS SUNDAY MAINLY IN THE 20S AND IN THE TEENS AND
20S MONDAY. LOWS SHOULD BE ZERO TO 15 ABOVE.
THE STORM SYSTEM CONTINUES MOVING EAST AND EXITS THE REGION MONDAY
NIGHT. A WESTERN SHORTWAVE RIDGE BUILDS BACK INTO THE DAKOTAS
TUESDAY/WEDNESDAY KEEPING THE FORECAST AREA DRY. A WARM-UP WITH
HIGHS IN THE 20S AND 30S TUESDAY THROUGH THURSDAY.
ON THURSDAY AN UPPER LEVEL SHORTWAVE TROUGH WITH A CLIPPER-TYPE LOW
IS PROGGED TO APPROACH NORTH DAKOTA. MODELS ARE DIFFERING ON TIMING
OF THAT FEATURE...SO HAVE KEPT THE THURSDAY DAYTIME FORECAST DRY FOR
NOW.
&&
.AVIATION...
WIDESPREAD IFR/MVFR CONDITIONS IN STRATUS AND FOG ACROSS WESTERN AND
CENTRAL NORTH DAKOTA WITH EMBEDDED LIFR CONDITIONS AND PATCHY
FREEZING DRIZZLE WILL CONTINUE FOR ALL TAF SITES EXCEPT KDIK...WHICH
REMAINS CLEAR AND JUST SOUTH AND WEST OF THE STRATUS DECK.
HOWEVER...THE STRATUS IS EXPECTED TO BUILD BACK IN LATE THIS EVENING
INTO TONIGHT. THE MODELS ARE SUGGESTING A BRIEF PERIOD THIS EVENING
OF IMPROVING CONDITIONS TO MVFR/VFR...HOWEVER THE STRATUS SHOULD
ENCOMPASS THE STATE AFT 06Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ001-002-
009-010-017-018.
&&
$$
SHORT TERM...AYD
LONG TERM/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1033 AM CST THU FEB 7 2013
.DISCUSSION...
THE MAIN CHANGE WITH THIS FORECAST UPDATE WAS TO REMOVE THE
MENTION OF FOG ACROSS THE NORTH CENTRAL THROUGH THE UPPER PORTIONS
OF THE JAMES RIVER VALLEY BASED UPON OBSERVED TRENDS THROUGH 1630
UTC. ALSO...MAINTAINED THE STRATUS ACROSS MUCH CENTRAL AND INTO
NORTHWEST NORTH DAKOTA THROUGH THE EVENING...AND MAY HAVE TO
EXTEND IT THROUGH TOMORROW AS LITTLE MIXING...THE LACK OF AN
AIRMASS EXCHANGE AND LOW LEVEL WARM AIR ADVECTION THROUGH THE
NIGHT ALL SUGGEST THE POTENTIAL FOR THE STRATUS TO REMAIN IN
PLACE. THIS IS SUPPORTED BY THE 12 UTC NAM/GFS BUFR SOUNDINGS AND
THE LATEST RAP RUNS.
&&
.AVIATION...
IFR/LIFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS
WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. CONDITIONS WILL BE
SLOW TO IMPROVE FROM WEST TO EAST THIS AFTERNOON.
HOWEVER...MVFR/VFR CONDITIONS ARE EXPECTED TO DEVELOP FROM
KISN/KDIK LATER THIS AFTERNOON WITH MVFR/VFR CONDITIONS EXPECTED
ACROSS KMOT/KBIS/KJMS BY THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
448 PM EST THU FEB 7 2013
.SYNOPSIS...
CLOUDS WILL INCREASE AND THICKEN TONIGHT AS A STORM SYSTEM
CONTINUES TO ORGANIZE FROM THE MIDWEST TO THE SOUTHEAST AND MID
ATLANTIC COAST. LIGHT MIXED PRECIPITATION WILL DEVELOP EARLY
FRIDAY MORNING IN THE SOUTHEAST UPSLOPE FLOW OVER CENTRAL
PENNSYLVANIA. A PERIOD OF MODERATE TO HEAVY SNOW IS EXPECTED TO
CROSS MUCH OF CENTRAL PENNSYLVANIA FRIDAY AFTERNOON AND EVENING
PRODUCING A FEW TO SEVERAL INCHES OF ACCUMULATION. HIGHEST
AMOUNTS WILL BE ACROSS THE NORTHERN AND ENDLESS MOUNTAIN REGIONS
WHERE UP TO 8 INCHES OF SNOW MAY FALL BY EARLY SATURDAY MORNING.
HIGH PRESSURE WILL BUILD IN BEHIND THE STORM ON SATURDAY AND SUNDAY.
A LOW PRESSURE SYSTEM SHOULD BRING ANOTHER PERIOD OF MIXED
PRECIPITATION ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CLOUDS INCREASE AND THICKEN TONIGHT AS THE ESE FLOW AROUND STRONG
QUEBEC HIGH PRESSURE AND DEVELOPING SOUTHEAST COASTAL LOW
INTENSIFIES. SPOTTY LIGHT SNOW OR FREEZING DRIZZLE MAY DEVELOP IN
THE PRE DAWN HOURS AS SUGGESTED BY THE RAP AND EVEN GFS...BUT
THINK THE THREAT IS GREATEST AFT 12Z WHEN MOISTURE FLUX BECOMES
MORE SIGNIFICANT. MINS SHOULD RANGE THROUGH THE 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
THIS MORNING`S SREF AND DETERMINISTIC NAM/GFS WARRANTED SOME
RAMPING UP OF QPF ACROSS CENTRAL AND NORTHERN PA. WHILE MODELS
KEEP NORTHERN AND SOUTHERN STREAM DISTURBANCES FROM PHASING IN
TIME TO PRODUCE AN EPIC STORM FOR PA...FRIDAY AFTERNOON AND
EVENING IMPACT WILL BE RELATIVELY HIGH WITH A 4 TO 6 HOUR PERIOD
OF MODERATE TO HEAVY SNOW AS THE STRONG AXIS OF DEFORMATION AHEAD
OF THE NORTHERN STREAM CENTER PROPAGATES EASTWARD. GIVEN THE
LIKELY IMPACT BUT STILL REASONABLE UNCERTAINTY...OPTED FOR A
WARNING WITH A WIDER RANGE (4 TO 8) REACHING THE 6 INCH MIDPOINT
CRITERIA FOR WARNINGS FROM WARREN COUNTY EASTWARD AND
SOUTHEASTWARD THROUGH POTTER...SULLIVAN COLUMBIA AND SCHUYLKILL
COUNTIES...INCLUDING LYCOMING COUNTY AND THE WILLIAMSPORT AREA.
FARTHER SOUTH...THE PERIOD OF LIGHT MIXED PRECIPITATION DURING THE
MORNING COMBINED WITH THE LATER AFTERNOON AND EVENING PERIOD OF
ACCUMULATING SNOW GARNERED AN ADVISORY FOR THE REMAINDER OF
CENTRAL PA. FAR SOUTHEAST COUNTIES (LANCASTER AND YORK) MAY BE
PLAIN RAIN FOR A WHILE...BUT A LATE AFTERNOON/EVENING PERIOD OF
SNOWFALL WITH 1 TO 3 INCHES OF SNOW IS LIKELY. LANCASTER COUNTY
MAY BE SUSCEPTIBLE TO A SLIGHTLY LONGER PERIOD OF ACCUMULATING
SNOW AS THE DEFORMATION AXIS STALLS FRIDAY NIGHT WHILE THE COASTAL
LOW STRENGTHENS.
HEADLINES ARE WELL COLLABORATED WITH OUR NORTHERN AND EASTERN
NEIGHBORS...BUT MAY BE ON THE PESSIMISTIC SIDE GIVEN THE IMPACT OF
AN AFTERNOON AND EVENING BURST OF SNOW. MEAN QPFS IN THE WARNING
AREAS RANGE FROM 0.4 TO 0.7 RANGE FROM THE NORTHERN TIER TO THE
LOWER SUSQ. RIVER VALLEY AS PER DETERMINISTIC RUNS...WITH PLUMES
GIVING HIGHER CONFIDENCE TO HIGH ADVISORY AMOUNTS OR APPROACHING
WARNING AMOUNTS FOR A GOOD PART OF NORTHERN AND EAST CENTRAL
AREAS. THE SNOW COULD LINGER INTO SATURDAY MORNING ACROSS FAR
NORTHEASTERN AREAS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A WINDY AND COLDER DAY IS EXPECTED SATURDAY...AS INTENSE COASTAL
LOW PASSES OUT TO SEA. SCT -SHSN/FLURRIES COULD BE POSSIBLE ACROSS
THE W MTNS EARLY SAT. HOWEVER...RAPIDLY FALLING INVERSION HGTS
WITH APPROACH OF SFC HIGH SHOULD CAUSE THEM TO TAPER OFF BY MIDDAY
AND KEEP ANY ADDITIONAL ACCUMS NEGLIGIBLE. MDL SOUNDINGS...WHICH
ARE WELL MIXED TO ARND 900MB...SUPPORT CONTINUED NWRLY GUSTS BTWN
20-30KTS...WITH THE HIGHEST WINDS ACROSS EASTERN PA. LG SCALE
SUBSIDENCE SHOULD PRODUCE MSUNNY SKIES ACROSS THE SUSQ VALLEY
SATURDAY...WHILE UPSLOPING FLOW BRINGS A GOOD DEAL OF STRATOCU TO
THE W MTNS...ESP EARLY. MIXING MDL 900MB TEMPS TO THE SFC YIELDS
HIGHS FROM THE M20S OVR THE ALLEGHENIES...TO THE M30S ACROSS THE
LOWER SUSQ VALLEY.
DIMINISHING WINDS AND CLEAR SKIES EXPECTED SAT NIGHT AS HIGH
PRESSURE BUILDS OVR THE STATE. HAVE LOWERED MINS A BIT BLW
GUIDANCE BASED ON SUCH FAVORABLE CONDS FOR RADIATIONAL COOLING.
ALTHOUGH THE AIR MASS IS NOT EXPECTED TO BE ESP COLD...FRESH SNOW
COVER COULD ALLOW READINGS TO MAKE A RUN AT ZERO OVR THE N MTNS.
LITTLE SPREAD AMONG MED RANGE MDL GUIDANCE THRU EARLY NEXT
WEEK...ALL OF WHICH TRACKS NEXT LOW PRES SYS WEST OF PA LATE SUN
NIGHT INTO MONDAY. DEPENDING ON TIMING...AND GIVEN THE SFC
TEMPS...IF PRECIP GETS IN EARLY ENOUGH...THERE COULD BE FZRA AND SFC
TEMPS SHOULD BE COLD ENOUGH FOR ICY CONDS EARLY MONDAY BEFORE A
CHANGE TO SHRA. THERE LOOKS TO BE A FINGER OF 850MB AIR FROM A LOW
LEVEL JET ASSOCIATED WITH THIS SYSTEM THAT COULD BRING IN SOME WAA
IN THE MID LEVEL THAT WOULD BRING THE MIXED PRECIPITATION EARLY.
LOOK FOR A WARM UP ON MONDAY INTO TUESDAY...BEFORE TEMPERATURES
DROP BACK DOWN TO MORE SEASONAL NORMS LATER IN THE WEEK.
AFTER MONDAY...ECMWF ENSEMBLE MEAN PATTERN FAVORS DRY AND SEASONABLE
CONDS THRU MIDWEEK WITH A SFC RIDGE BUILDING INTO THE STATE. THE
NEXT LOW LOOKS TO TRACK THROUGH THE GREAT LAKES REGION AND INTO
THE NE BY PASSING PA AS A RIDGE BUILDS OVER THE AREA.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
MINOR ADJUSTMENTS MADE TO THE 21Z TAFS.
EARLIER DISCUSSION BELOW.
VFR CONDITIONS THIS EVENING BEFORE FLYING CONDITIONS GO DOWNHILL
LATER TONIGHT AND FRIDAY MORNING. MIXED PRECIPITATION AND MVFR/LCL
IFR CIGS WILL DEVELOP FRIDAY MORNING AND CONTINUE INTO EARLY
AFTERNOON. AN AREA OF MODERATE TO HEAVY SNOW WILL PROPOGATE
EASTWARD DURING THE MID TO LATE AFTERNOON AND EVENING...BRINGING
IFR TO LCL LIFR CONDS ESP CENTRAL AND NORTH...WITH A PERIOD OF IFR
AND LCL LIFR CONDS POSSIBLE ACROSS THE SOUTH FRI EVENING. CONDS
WILL IMPROVE TO MVFR EARLY SAT MORNING AS COASTAL LOW PRESSURE
MOVES AWAY. SCT -SHSN EXPECTED IN THE SNOWBELT REGION THROUGH SAT
AFTN BEFORE DISSIPATING LATE IN THE DAY.
OUTLOOK...
SAT...MVFR/IFR EARLY BCMG MVFR/VFR. SNOW ENDING WEST TO EAST.
STRONG N WINDS.
SUN...VFR NO SIG WX.
MON...AM WINTRY MIX TO RAIN. FROPA. -SHSN WEST LATE.
TUE...MAINLY VFR...BUT MVFR PSBL NW EARLY WITH -SHSN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 7 AM FRIDAY TO 7 AM EST SATURDAY FOR
PAZ004>006-037-041-042-046-051>053-058.
WINTER WEATHER ADVISORY FROM 7 AM FRIDAY TO 7 AM EST SATURDAY
FOR PAZ010>012-017>019-024>028-033>036-045-049-050-056-057-059-
063>066.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/CERU
AVIATION...DEVOIR/MARTIN/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
419 PM EST THU FEB 7 2013
.SYNOPSIS...
CLOUDS WILL INCREASE AND THICKEN TONIGHT AS A STORM SYSTEM
CONTINUES TO ORGANIZE FROM THE MIDWEST TO THE SOUTHEAST AND MID
ATLANTIC COAST. LIGHT MIXED PRECIPITATION WILL DEVELOP EARLY
FRIDAY MORNING IN THE SOUTHEAST UPSLOPE FLOW OVER CENTRAL
PENNSYLVANIA. A PERIOD OF MODERATE TO HEAVY SNOW IS EXPECTED TO
CROSS MUCH OF CENTRAL PENNSYLVANIA FRIDAY AFTERNOON AND EVENING
PRODUCING A FEW TO SEVERAL INCHES OF ACCUMULATION. HIGHEST
AMOUNTS WILL BE ACROSS THE NORTHERN AND ENDLESS MOUNTAIN REGIONS
WHERE UP TO 8 INCHES OF SNOW MAY FALL BY EARLY SATURDAY MORNING.
HIGH PRESSURE WILL BUILD IN BEHIND THE STORM ON SATURDAY AND SUNDAY.
A LOW PRESSURE SYSTEM SHOULD BRING ANOTHER PERIOD OF MIXED
PRECIPITATION ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CLOUDS INCREASE AND THICKEN TONIGHT AS THE ESE FLOW AROUND STRONG
QUEBEC HIGH PRESSURE AND DEVELOPING SOUTHEAST COASTAL LOW
INTENSIFIES. SPOTTY LIGHT SNOW OR FREEZING DRIZZLE MAY DEVELOP IN
THE PRE DAWN HOURS AS SUGGESTED BY THE RAP AND EVEN GFS...BUT
THINK THE THREAT IS GREATEST AFT 12Z WHEN MOISTURE FLUX BECOMES
MORE SIGNIFICANT. MINS SHOULD RANGE THROUGH THE 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
THIS MORNING`S SREF AND DETERMINISTIC NAM/GFS WARRANTED SOME
RAMPING UP OF QPF ACROSS CENTRAL AND NORTHERN PA. WHILE MODELS
KEEP NORTHERN AND SOUTHERN STREAM DISTURBANCES FROM PHASING IN
TIME TO PRODUCE AN EPIC STORM FOR PA...FRIDAY AFTERNOON AND
EVENING IMPACT WILL BE RELATIVELY HIGH WITH A 4 TO 6 HOUR PERIOD
OF MODERATE TO HEAVY SNOW AS THE STRONG AXIS OF DEFORMATION AHEAD
OF THE NORTHERN STREAM CENTER PROPAGATES EASTWARD. GIVEN THE
LIKELY IMPACT BUT STILL REASONABLE UNCERTAINTY...OPTED FOR A
WARNING WITH A WIDER RANGE (4 TO 8) REACHING THE 6 INCH MIDPOINT
CRITERIA FOR WARNINGS FROM WARREN COUNTY EASTWARD AND
SOUTHEASTWARD THROUGH POTTER...SULLIVAN COLUMBIA AND SCHUYLKILL
COUNTIES...INCLUDING LYCOMING COUNTY AND THE WILLIAMSPORT AREA.
FARTHER SOUTH...THE PERIOD OF LIGHT MIXED PRECIPITATION DURING THE
MORNING COMBINED WITH THE LATER AFTERNOON AND EVENING PERIOD OF
ACCUMULATING SNOW GARNERED AN ADVISORY FOR THE REMAINDER OF
CENTRAL PA. FAR SOUTHEAST COUNTIES (LANCASTER AND YORK) MAY BE
PLAIN RAIN FOR A WHILE...BUT A LATE AFTERNOON/EVENING PERIOD OF
SNOWFALL WITH 1 TO 3 INCHES OF SNOW IS LIKELY. LANCASTER COUNTY
MAY BE SUSCEPTIBLE TO A SLIGHTLY LONGER PERIOD OF ACCUMULATING
SNOW AS THE DEFORMATION AXIS STALLS FRIDAY NIGHT WHILE THE COASTAL
LOW STRENGTHENS.
HEADLINES ARE WELL COLLABORATED WITH OUR NORTHERN AND EASTERN
NEIGHBORS...BUT MAY BE ON THE PESSIMISTIC SIDE GIVEN THE IMPACT OF
AN AFTERNOON AND EVENING BURST OF SNOW. MEAN QPFS IN THE WARNING
AREAS RANGE FROM 0.4 TO 0.7 RANGE FROM THE NORTHERN TIER TO THE
LOWER SUSQ. RIVER VALLEY AS PER DETERMINISTIC RUNS...WITH PLUMES
GIVING HIGHER CONFIDENCE TO HIGH ADVISORY AMOUNTS OR APPROACHING
WARNING AMOUNTS FOR A GOOD PART OF NORTHERN AND EAST CENTRAL
AREAS. THE SNOW COULD LINGER INTO SATURDAY MORNING ACROSS FAR
NORTHEASTERN AREAS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A WINDY AND COLDER DAY IS EXPECTED SATURDAY...AS INTENSE COASTAL
LOW PASSES OUT TO SEA. SCT -SHSN/FLURRIES COULD BE POSSIBLE ACROSS
THE W MTNS EARLY SAT. HOWEVER...RAPIDLY FALLING INVERSION HGTS
WITH APPROACH OF SFC HIGH SHOULD CAUSE THEM TO TAPER OFF BY MIDDAY
AND KEEP ANY ADDITIONAL ACCUMS NEGLIGIBLE. MDL SOUNDINGS...WHICH
ARE WELL MIXED TO ARND 900MB...SUPPORT CONTINUED NWRLY GUSTS BTWN
20-30KTS...WITH THE HIGHEST WINDS ACROSS EASTERN PA. LG SCALE
SUBSIDENCE SHOULD PRODUCE MSUNNY SKIES ACROSS THE SUSQ VALLEY
SATURDAY...WHILE UPSLOPING FLOW BRINGS A GOOD DEAL OF STRATOCU TO
THE W MTNS...ESP EARLY. MIXING MDL 900MB TEMPS TO THE SFC YIELDS
HIGHS FROM THE M20S OVR THE ALLEGHENIES...TO THE M30S ACROSS THE
LOWER SUSQ VALLEY.
DIMINISHING WINDS AND CLEAR SKIES EXPECTED SAT NIGHT AS HIGH
PRESSURE BUILDS OVR THE STATE. HAVE LOWERED MINS A BIT BLW
GUIDANCE BASED ON SUCH FAVORABLE CONDS FOR RADIATIONAL COOLING.
ALTHOUGH THE AIR MASS IS NOT EXPECTED TO BE ESP COLD...FRESH SNOW
COVER COULD ALLOW READINGS TO MAKE A RUN AT ZERO OVR THE N MTNS.
LITTLE SPREAD AMONG MED RANGE MDL GUIDANCE THRU EARLY NEXT
WEEK...ALL OF WHICH TRACKS NEXT LOW PRES SYS WEST OF PA LATE SUN
NIGHT INTO MONDAY. DEPENDING ON TIMING...AND GIVEN THE SFC
TEMPS...IF PRECIP GETS IN EARLY ENOUGH...THERE COULD BE FZRA AND SFC
TEMPS SHOULD BE COLD ENOUGH FOR ICY CONDS EARLY MONDAY BEFORE A
CHANGE TO SHRA. THERE LOOKS TO BE A FINGER OF 850MB AIR FROM A LOW
LEVEL JET ASSOCIATED WITH THIS SYSTEM THAT COULD BRING IN SOME WAA
IN THE MID LEVEL THAT WOULD BRING THE MIXED PRECIPITATION EARLY.
LOOK FOR A WARM UP ON MONDAY INTO TUESDAY...BEFORE TEMPERATURES
DROP BACK DOWN TO MORE SEASONAL NORMS LATER IN THE WEEK.
AFTER MONDAY...ECMWF ENSEMBLE MEAN PATTERN FAVORS DRY AND SEASONABLE CONDS
THRU MIDWEEK WITH A SFC RIDGE BUILDING INTO THE STATE.
THE NEXT LOW LOOKS TO TRACK THROUGH THE GREAT LAKES REGION AND
INTO THE NE BY PASSING PA AS A RIDGE BUILDS OVER THE AREA.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS THIS EVENING BEFORE FLYING CONDITIONS GO DOWNHILL
LATER TONIGHT AND FRIDAY MORNING. MIXED PRECIPITATION AND MVFR/LCL
IFR CIGS WILL DEVELOP FRIDAY MORNING AND CONTINUE INTO EARLY
AFTERNOON. AN AREA OF MODERATE TO HEAVY SNOW WILL PROPOGATE
EASTWARD DURING THE MID TO LATE AFTERNOON AND EVENING...BRINGING
IFR TO LCL LIFR CONDS ESP CENTRAL AND NORTH...WITH A PERIOD OF IFR
AND LCL LIFR CONDS POSSIBLE ACROSS THE SOUTH FRI EVENING. CONDS
WILL IMPROVE TO MVFR EARLY SAT MORNING AS COASTAL LOW PRESSURE
MOVES AWAY. SCT -SHSN EXPECTED IN THE SNOWBELT REGION THROUGH SAT
AFTN BEFORE DISSIPATING LATE IN THE DAY.
OUTLOOK... FRI...IFR-LIFR. AM MIXED
PRECIP SOUTH/PM SNOW. SNOW/SLEET NORTH. STRONG NNW WIND DEVELOPING
LATE.
SAT...MVFR/IFR EARLY BCMG MVFR/VFR. SNOW ENDING WEST TO
EAST. STRONG NNW WINDS EARLY.
SUN...BCMG VFR NO SIG WX.
MON...AM WINTRY MIX TO RAIN. FROPA. -SHSN WEST LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 7 AM FRIDAY TO 7 AM EST SATURDAY FOR
PAZ004>006-037-041-042-046-051>053-058.
WINTER WEATHER ADVISORY FROM 7 AM FRIDAY TO 7 AM EST SATURDAY
FOR PAZ010>012-017>019-024>028-033>036-045-049-050-056-057-059-
063>066.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/CERU
AVIATION...DEVOIR/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
244 PM EST THU FEB 7 2013
.SYNOPSIS...
CLOUDS WILL INCREASE AND THICKEN TONIGHT AS A STORM SYSTEM
CONTINUES TO ORGANIZE FROM THE MIDWEST TO THE SOUTHEAST AND MID
ATLANTIC COAST. LIGHT MIXED PRECIPITATION WILL DEVELOP EARLY
FRIDAY MORNING IN THE SOUTHEAST UPSLOPE FLOW OVER CENTRAL
PENNSYLVANIA. A PERIOD OF MODERATE TO HEAVY SNOW IS EXPECTED TO
CROSS MUCH OF CENTRAL PENNSYLVANIA FRIDAY AFTERNOON AND EVENING
PRODUCING A FEW TO SEVERAL INCHES OF ACCUMULATION. HIGHEST
AMOUNTS WILL BE ACROSS THE NORTHERN AND ENDLESS MOUNTAIN REGIONS
WHERE UP TO 8 INCHES OF SNOW MAY FALL BY EARLY SATURDAY MORNING.
HIGH PRESSURE WILL BUILD IN BEHIND THE STORM ON SATURDAY AND SUNDAY.
A LOW PRESSURE SYSTEM SHOULD BRING ANOTHER PERIOD OF MIXED
PRECIPITATION ON MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CLOUDS INCREASE AND THICKEN TONIGHT AS THE ESE FLOW AROUND STRONG
QUEBEC HIGH PRESSURE AND DEVELOPING SOUTHEAST COASTAL LOW
INTENSIFIES. SPOTTY LIGHT SNOW OR FREEZING DRIZZLE MAY DEVELOP IN
THE PRE DAWN HOURS AS SUGGESTED BY THE RAP AND EVEN GFS...BUT
THINK THE THREAT IS GREATEST AFT 12Z WHEN MOISTURE FLUX BECOMES
MORE SIGNIFICANT. MINS SHOULD RANGE THROUGH THE 20S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THIS MORNING`S SREF AND DETERMINISTIC NAM/GFS WARRANTED SOME
RAMPING UP OF QPF ACROSS CENTRAL AND NORTHERN PA. WHILE MODELS
KEEP NORTHERN AND SOUTHERN STREAM DISTURBANCES FROM PHASING IN
TIME TO PRODUCE AN EPIC STORM FOR PA...FRIDAY AFTERNOON AND
EVENING IMPACT WILL BE RELATIVELY HIGH WITH A 4 TO 6 HOUR PERIOD
OF MODERATE TO HEAVY SNOW AS THE STRONG AXIS OF DEFORMATION AHEAD
OF THE NORTHERN STREAM CENTER PROPOGATES EASTWARD. GIVEN THE
LIKELY IMPACT BUT STILL REASONABLE UNCERTAINTY...OPTED FOR A
WARNING WITH A WIDER RANGE (4 TO 8) REACHING THE 6 INCH MIDPOINT
CRITERIA FOR WARNINGS FROM WARREN COUNTY EASTWARD AND
SOUTHEASTWARD THROUGH POTTER...SULLIVAN COLUMBIA AND SCHUYLKILL
COUNTIES...INCLUDING LYCOMING COUNTY AND THE WILLIAMSPORT AREA.
FARTHER SOUTH...THE PERIOD OF LIGHT MIXED PRECIPITATION DURING THE
MORNING COMBINED WITH THE LATER AFTERNOON AND EVENING PERIOD OF
ACCUMULATING SNOW GARNERED AN ADVISORY FOR THE REMAINDER OF
CENTRAL PA. FAR SOUTHEAST COUNTIES (LANCASTER AND YORK) MAY BE
PLAIN RAIN FOR A WHILE...BUT A LATE AFTERNOON/EVENING PERIOD OF
SNOWFALL WITH 1 TO 3 INCHES OF SNOW IS LIKELY. LANCASTER COUNTY
MAY BE SUSCEPTIBLE TO A SLIGHTLY LONGER PERIOD OF ACCUMULATING
SNOW AS THE DEFORMATION AXIS STALLS FRIDAY NIGHT WHILE THE COASTAL
LOW STRENGTHENS.
HEADLINES ARE WELL COLLABORATED WITH OUR NORTHERN AND EASTERN
NEIGHBORS...BUT MAY BE ON THE PESSIMISTIC SIDE GIVEN THE IMPACT OF
AN AFTERNOON AND EVENING BURST OF SNOW. MEAN QPFS IN THE WARNING
AREAS RANGE FROM 0.4 TO 0.7 RANGE FROM THE NORTHERN TIER TO THE
LOWER SUSQ. RIVER VALLEY AS PER DETERMINISTIC RUNS...WITH PLUMES
GIVING HIGHER CONFIDENCE TO HIGH ADVISORY AMOUNTS OR APPROACHING
WARNING AMOUNTS FOR A GOOD PART OF NORTHERN AND EAST CENTRAL
AREAS. THE SNOW COULD LINGER INTO SATURDAY MORNING ACROSS FAR
NORTHEASTERN AREAS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
A WINDY AND COLDER DAY IS EXPECTED SATURDAY...AS INTENSE COASTAL
LOW PASSES OUT TO SEA. SCT -SHSN/FLURRIES COULD BE POSSIBLE ACROSS
THE W MTNS EARLY SAT. HOWEVER...RAPIDLY FALLING INVERSION HGTS
WITH APPROACH OF SFC HIGH SHOULD CAUSE THEM TO TAPER OFF BY MIDDAY
AND KEEP ANY ADDITIONAL ACCUMS NEGLIGIBLE. MDL SOUNDINGS...WHICH
ARE WELL MIXED TO ARND 900MB...SUPPORT CONTINUED NWRLY GUSTS BTWN
20-30KTS...WITH THE HIGHEST WINDS ACROSS EASTERN PA. LG SCALE
SUBSIDENCE SHOULD PRODUCE MSUNNY SKIES ACROSS THE SUSQ VALLEY
SATURDAY...WHILE UPSLOPING FLOW BRINGS A GOOD DEAL OF STRATOCU TO
THE W MTNS...ESP EARLY. MIXING MDL 900MB TEMPS TO THE SFC YIELDS
HIGHS FROM THE M20S OVR THE ALLEGHENIES...TO THE M30S ACROSS THE
LOWER SUSQ VALLEY.
DIMINISHING WINDS AND CLEAR SKIES EXPECTED SAT NIGHT AS HIGH
PRESSURE BUILDS OVR THE STATE. HAVE LOWERED MINS A BIT BLW
GUIDANCE BASED ON SUCH FAVORABLE CONDS FOR RADIATIONAL COOLING.
ALTHOUGH THE AIR MASS IS NOT EXPECTED TO BE ESP COLD...FRESH SNOW
COVER COULD ALLOW READINGS TO MAKE A RUN AT ZERO OVR THE N MTNS.
LITTLE SPREAD AMONG MED RANGE MDL GUIDANCE THRU EARLY NEXT
WEEK...ALL OF WHICH TRACKS NEXT LOW PRES SYS WEST OF PA SUN NITE
AND MONDAY. IF PRECIP GETS IN EARLY ENOUGH...SFC TEMPS SHOULD BE
COLD ENOUGH FOR ICY CONDS EARLY MONDAY BEFORE A CHANGE TO SHRA.
ECMWF ENSEMBLE MEAN PATTERN FAVORS DRY AND SEASONABLE CONDS THRU
MIDWEEK WITH A SFC RIDGE BUILDING INTO THE STATE. HOWEVER...GEFS
DATA INDICATES A LESS PROGRESSIVE PATTERN WITH UPPER TROF
REMAINING WEST OF PA AND THE POTENTIAL OF WEAK DISTURBANCES RIDING
UP THE E COAST.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS THIS EVENING BEFORE FLYING CONDITIONS GO DOWNHILL
LATER TONIGHT AND FRIDAY MORNING. MIXED PRECIPITATION AND MVFR/LCL
IFR CIGS WILL DEVELOP FRIDAY MORNING AND CONTINUE INTO EARLY
AFTERNOON. AN AREA OF MODERATE TO HEAVY SNOW WILL PROPOGATE
EASTWARD DURING THE MID TO LATE AFTERNOON AND EVENING...BRINGING
IFR TO LCL LIFR CONDS ESP CENTRAL AND NORTH...WITH A PERIOD OF IFR
AND LCL LIFR CONDS POSSIBLE ACROSS THE SOUTH FRI EVENING. CONDS
WILL IMPROVE TO MVFR EARLY SAT MORNING AS COASTAL LOW PRESSURE
MOVES AWAY. SCT -SHSN EXPECTED IN THE SNOWBELT REGION THROUGH SAT
AFTN BEFORE DISSIPATING LATE IN THE DAY.
OUTLOOK... FRI...IFR-LIFR. AM MIXED
PRECIP SOUTH/PM SNOW. SNOW/SLEET NORTH. STRONG NNW WIND DEVELOPING
LATE.
SAT...MVFR/IFR EARLY BCMG MVFR/VFR. SNOW ENDING WEST TO
EAST. STRONG NNW WINDS EARLY.
SUN...BCMG VFR NO SIG WX.
MON...AM WINTRY MIX TO RAIN. FROPA. -SHSN WEST LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 7 AM FRIDAY TO 7 AM EST SATURDAY FOR
PAZ004>006-037-041-042-046-051>053-058.
WINTER WEATHER ADVISORY FROM 7 AM FRIDAY TO 7 AM EST SATURDAY
FOR PAZ010>012-017>019-024>028-033>036-045-049-050-056-057-059-
063>066.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...GRUMM/FITZGERALD
AVIATION...DEVOIR
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1054 AM CST THU FEB 7 2013
.DISCUSSION.../ISSUED AT 1054 AM CST/
A LARGE SWATH OF LOW LEVEL STRATUS CURRENTLY LOCKED IN ACROSS THE
NORTHERN PLAINS AND UPPER MIDWEST THIS MORNING. WITH LOW LEVEL
NORTHERLY WINDS EXPECTED TO PERSIST THROUGH AT LEAST MIDNIGHT
TONIGHT...DO NOT EXPECT MUCH IF ANY IMPROVEMENT IN CLOUD COVER
ACROSS THE ENTIRE TODAY...WHICH IS SUPPORTED BY THE RAP AND SREF.
COULD SEE SOME LIFTING NEAR THE MISSOURI VALLEY...BUT WITH SATELLITE
LOOPS DEPICTING THE STRATUS EXTENDING WELL SOUTH OF THE CWA...WILL
LEAVE CLOUDS IN PLACE EVERYWHERE. WITH THE STRATUS IN AND NORTHERLY
WINDS IN PLACE...TEMPERATURES WILL NOT BUDGE MUCH FROM CURRENT
READINGS IN THE 20S. DID LOWER HIGHS A FEW DEGREES IN THE SOUTH WITH
THE EXPECTATION THAT THE STRATUS WILL PERSIST BUT MAY HAVE TO LOWER
FURTHER IF TEMPERATURE TRENDS CONTINUE...ESPECIALLY IN SOUTH CENTRAL
SOUTH DAKOTA.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
LOW STRATUS LAYER IS EXPECTED TO PERSIST ACROSS THE ENTIRE FORECAST
AREA THROUGH TODAY AND TONIGHT WITH NORTHERLY WINDS IN PLACE.
CEILINGS WILL GENERALLY BE AROUND 600 TO 1000 FEET THROUGH THE TAF
BUT COULD BRIEFLY RISE TO THE 1500 FOOT RANGE THIS AFTERNOON.
VISIBILITY WILL BE AS LOW AS 3SM THROUGH AROUND 08/03Z WITH LOWER
CONDITIONS TO AROUND 2 TO 5 SM POSSIBLE OVERNIGHT. GRADUAL CEILING
AND VISIBILITY IMPROVEMENT WILL BEGIN AFTER 08/09Z WITH WINDS
TURNING SOUTHERLY...LIKELY BEGINNING FROM THE SOUTHWESTERN CWA AND
EXPANDING NORTHEAST THROUGH 18Z.
&&
.PREV DISCUSSION.../ISSUED AT 438 AM CST/
STRATUS CONTINUES TO MOVE IN FROM THE NORTH AND EXTENDS WELL INTO
NORTH DAKOTA. WITH WEAK NORTHERLY BOUNDARY LAYER FLOW CONTINUING
THOUGH THE DAY...FEELING IS THIS STRATUS WILL LINGER FOR MOST OF THE
DAY ACROSS THE ENTIRE CWA. THIS IS SHOWN WELL BY THE RAP AND HRRR.
THINKING IS THE STRATUS BEGINS TO ERODE ON THE SOUTHERN EDGE A BIT
BY LATE IN THE DAY...WITH THE BEST CHANCE OF CLEARING TOWARDS THE
MISSOURI RIVER. WITH THE CLOUD COVER...WENT AHEAD AND CONTINUED THE
DOWNWARD TREND WITH HIGHS. HOWEVER WOULD NOT BE SURPRISED IF
SOUTHERN AREAS ARE STILL FORECAST A BIT TOO WARM...BUT DID NOT WANT
TO GO TOO COOL IN CASE THE SUN DOES MANAGE TO COME OUT THIS
AFTERNOON. COULD SEE A BIT OF PATCHY FREEZING DRIZZLE ACROSS HIGHWAY
14 CORRIDOR THIS MORNING WHERE MOISTURE IS DEEPEST...BUT CURRENTLY
NOT EXPECTING ANYTHING WIDESPREAD. AS BOUNDARY LAYER FLOW TURNS MORE
EASTERLY TONIGHT...THINKING STRATUS AND AREAS OF FOG REMAIN OR
REFORM OVER MOST OF THE AREA...ESPECIALLY EAST OF THE JAMES RIVER.
WITH THE CLOUDS AND LIGHT BREEZE...STAYED ON THE WARMER SIDE OF
GUIDANCE FOR LOWS...MAINLY TEENS AND LOWER 20S. HIGHS A BIT TRICKY
ON FRIDAY...WITH STRATUS LIKELY SLOW TO EXIT ACROSS OUR EAST. NAM IS
A BIT OF AN OUTLIER WARMING THE LOW LEVELS QUICKEST...THUS FOLLOWED
CLOSER TO THE ECMWF AND GFS SOLUTIONS...WITH HIGHS IN THE LOW 30S
SOUTHWEST MINNESOTA TO THE LOW 50S NEAR GREGORY COUNTY. A 30 TO 40
KT JET AT 925MB WILL LIKELY PUSH SOUTHERLY WINDS TO NEAR ADVISORY
CRITERIA FRIDAY AFTERNOON WEST OF THE JAMES RIVER. SOUTHERLY WINDS
WILL STAY BLUSTERY ACROSS THE ENTIRE CWA FRIDAY NIGHT...KEEPING LOWS
MAINLY IN THE MID TO UPPER 20S.
ATTENTION THEN TURNS TO A WAVE EJECTING OUT OF THE COLORADO ROCKIES
AND INTO THE PLAINS. MODELS STILL IN FAIRLY GOOD AGREEMENT WITH THIS
SYSTEM...BUT JUST SLIGHT SHIFTS IN THE TRACK WILL HAVE SIGNIFICANT
IMPACTS ON WEATHER TYPE ACROSS OUR CWA. GFS AND ECMWF HAVE TRENDED
SLIGHTLY FURTHER NORTH WITH THE WAVE AND SURFACE LOW...AND THUS
WARMER WITH THEIR TEMPERATURE PROFILES. GFS ENSEMBLE MEAN IS VERY
CLOSE TO THE ECMWF...AND THUS WILL FOLLOW A SOLUTION CLOSEST TO THE
ECMWF FOR NOW. THIS RESULTS IN A SOUTH TO NORTH MOVING AREA OF
MODERATE TO AT TIMES HEAVY PRECIPITATION SATURDAY NIGHT INTO SUNDAY
MORNING...WITH THE DRY SLOT MOVING INTO NORTHWEST IOWA ON
SUNDAY...AND THE HEAVIER PRECIP BAND ACROSS OUR NORTHWEST.
TEMPERATURE PROFILES CONTINUE TO SUPPORT A MAINLY RAIN EVENT ACROSS
NORTHWEST IOWA...WITH EVEN AN ISOLATED THUNDERSTORM POSSIBLE. IN THE
SIOUX FALLS AREA AND VICINITY...IT LOOKS LIKE RAIN
INITIALLY...BEFORE POSSIBLY MIXING OR CHANGING TO SNOW AS
EVAPORATIVE AND DYNAMIC COOLING TAKE PLACE LATE SATURDAY
NIGHT...THEN BACK TO ALL RAIN SUNDAY MORNING AS THE LOW APPROACHES
AND WARM LOW LEVEL TEMPERATURES MOVE IN...AND FINALLY BACK TO SOME
SNOW SUNDAY EVENING AS THE INVERTED TROUGH PUSHES EAST AND COLD AIR
RUSHES IN ON THE BACKSIDE OF THE STORM. THE FURTHER NORTH TRACK ALSO
SUGGESTS THAT SOME RAIN MAY OCCUR AS FAR NORTHWEST AS HURON SATURDAY
EVENING BEFORE COLD AIR MOVES IN OVERNIGHT. OVERALL...THE AREA OF
GREATEST SNOWFALL POTENTIAL REMAINS FROM CHAMBERLAIN TO HURON TO
JUST NORTH OF BROOKINGS AND MARSHALL...WHERE 6 OR MORE INCHES SEEM
POSSIBLE. OTHER ISSUE WILL BE STRONG NORTHWEST WINDS LATER SUNDAY
AFTERNOON INTO SUNDAY NIGHT ON THE COLD SIDE OF THE INVERTED TROUGH.
ADVISORY LEVEL WINDS SEEM PROBABLE...AND THIS COMBINED WITH THE SNOW
MAY CAUSE BLIZZARD OR NEAR BLIZZARD CONDITIONS IN THE ABOVE AREA
WHERE SNOW AMOUNTS WILL BE HIGHEST. ACCUMULATIONS SHOULD DROP OFF AS
YOU HEAD SOUTHEAST OF THIS REGION...WHERE RAIN SHOULD HOLD AMOUNTS
DOWN. AGAIN...ANY SHIFT IN STORM TRACK WILL SHIFT THE ABOVE
DESCRIPTION. FOR EXAMPLE...THE GEM IS BY FAR THE FURTHEST SOUTH
SOLUTION SHOWING THE HEAVIEST SNOW ALONG THE INTERSTATE 90 CORRIDOR.
THIS OUTLIER SOLUTION IS BEING DISCARDED AT THIS TIME...BUT FUTURE
TRENDS IN MODELS SOLUTIONS WILL HAVE TO BE MONITORED. /CHENARD
WITH CYCLONIC FLOW THROUGHOUT THE ATMOSPHERE AND A SECOND WEAK WAVE
MOVING ACROSS WESTERN MINNESOTA...LIKELY TO BE A LOT OF CLOUDS EAST
OF I29 MONDAY...ESPECIALLY EARLY IN THE DAY. THERE ALSO BE ENOUGH
LIFT TO PRODUCE SOME FLURRIES OR LIGHT SNOW...PRIMARILY IN SOUTHWEST
MINNESOTA. ANY ACCUMULATIONS WOULD BE LESS THAN AN INCH IF THERE IS
ANY. HOWEVER...925 MB WINDS IN ALL MODELS ARE STILL FROM 30 TO 40
KTS THROUGH MIDDAY BEFORE WEAKENING AS A RIDGE MOVES IN FROM THE
WEST AND WINDS DECREASE. WITH A FAIRLY WELL MIXED BOUNDARY
LAYER...WOULD EXPECT SUSTAINED WINDS OVER 20 MPH WITH GUSTS AGAIN
OVER 30 MPH FOR MUCH OF THE DAY EAST OF I29.
AFTER MONDAY THERE ARE DIFFERENCES BETWEEN THE ECMWF AND GFS IN HOW
FAST THE SURFACE RIDGE MOVES EAST AND THEN THE DEGREE OF WARMING
TOWARD THE MIDDLE OF NEXT WEEK. THE ECMWF IS SLOWER WITH THIS RIDGE
AND ALSO WARMER BY NEXT WEDNESDAY WITH THE POSSIBILITY OF
APPROACHING OR EVEN RISING ABOVE FREEZING WEDNESDAY AFTERNOON IN
MOST OF THE AREA. THE GFS WOULD KEEP TEMPERATURE WITHIN A COUPLE OF
DEGREES OF NORMAL. WITH UNCERTAINTY IN BOTH THE DEGREE OF WARMING
AND THE AMOUNT OF SNOWCOVER THAT WILL EXIST...STAYED WITH A COOLER
CONSENSUS FORECAST WITH HIGHS IN THE 20S TO LOWER 30S ON
TUESDAY...AND ABOUT 3 TO 5 DEGREES WARMER ON WEDNESDAY. TUESDAY AND
WEDNESDAY ARE EXPECTED TO BE DRY./SCHUMACHER
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1153 AM CST THU FEB 7 2013
.SHORT TERM...TODAY THROUGH SATURDAY
344 AM CST THU FEB 7 2013
MAIN FORECAST CONCERNS ARE ON FREEZING RAIN AND SNOW TODAY. FOCUS
THEN TURNS TO SYSTEM IMPACTING THE AREA LATE SATURDAY INTO
SUNDAY...BRINGING ANOTHER ROUND OF MIXED PRECIPITATION TO THE AREA.
LATEST SURFACE OBSERVATIONS SHOWED A LOW CLOUD DECK OVER NORTH
CENTRAL INTO CENTRAL WISCONSIN WITH CLOUD BASES AROUND 300 FT. THIS
LOW CLOUD DECK WAS PRODUCING SOME LIGHT FREEZING DRIZZLE ACROSS
NORTH CENTRAL WISCONSIN. FURTHER TO THE SOUTH...PERIODS OF FREEZING
RAIN AND SLEET CONTINUE IN FAR SOUTHWEST WISCONSIN INTO PORTIONS OF
NORTHEAST IOWA PRODUCING ICY ROADS. THERE HAS BEEN A BREAK IN THE
PRECIPITATION ACROSS SOUTHEAST MINNESOTA INTO WEST CENTRAL
WISCONSIN. AREAS OF FOG WERE DEVELOPING ACROSS SOUTHERN MINNESOTA
WITH VISIBILITIES FALLING TO AROUND 1/2 MILE OR LESS.
UPPER LEVEL TROUGH WILL MOVE EAST OUT OF THE DAKOTAS EARLY THIS
MORNING...PUSHING INTO THE UPPER MISSISSIPPI RIVER VALLEY LATE THIS
MORNING INTO EARLY THIS AFTERNOON. MEANWHILE...A SURFACE TROUGH
EXTENDING FROM CENTRAL IOWA NORTH INTO WESTERN WISCONSIN WILL DEEPEN
BEFORE SHIFTING EAST AND WRAPPING INTO A STRONG LOW. MESOSCALE
MODELS CONTINUE TO SHOW A FREEZING DRIZZLE SIGNATURE ALONG AND EAST
OF THE MISSISSIPPI RIVER LATE THIS MORNING INTO THE AFTERNOON HOURS
WITHIN THE INVERTED TROUGH. FORECAST SOUNDINGS SHOW A SATURATED
LAYER FROM JUST ABOVE THE SURFACE THROUGH 4KFT. THERE IS WEAK LIFT
WITHIN THIS LAYER...BETWEEN 950 AND 850 MB. THIS WILL BE ENOUGH TO
SUPPORT LIGHT FREEZING DRIZZLE. WILL HAVE TO KEEP A CLOSE WATCH ICE
ALOFT ACROSS SOUTHWEST INTO CENTRAL WISCONSIN...WHERE THERE IS THE
POTENTIAL TO SEE ACCUMULATING SNOW. 06Z NAM GUIDANCE SUGGESTS
SATURATION WILL BE DEEP ENOUGH OVER THESE AREAS FOR ICE ALOFT AND
POSSIBLY 1 TO 2 INCHES OF SNOW. PLAN ON HIGH TEMPERATURES TODAY
RANGING FROM AROUND 30 OVER NORTH CENTRAL WISCONSIN TO THE MID 30S
OVER NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
HIGH PRESSURE WILL BUILD INTO THE AREA LATE TONIGHT INTO FRIDAY
MORNING. A POTENT TROUGH IS EXPECTED TO DIVE SOUTHWEST CONUS AND
WILL TAKE AIM ON THE UPPER MIDWEST LATE FRIDAY INTO SATURDAY. PLAN
ON PARTLY TO MOSTLY SUNNY SKIES ON FRIDAY WITH HIGHS RANGING FROM
THE MID 20S OVER NORTH CENTRAL WISCONSIN TO AROUND 30 OVER NORTHEAST
IOWA. THE HIGH WILL SLIDE EAST OF THE REGION ON SATURDAY AS THE
TROUGH EJECTS OUT OF THE ROCKIES INTO THE CENTRAL PLAINS. THE TROUGH
IS EXPECTED TO CLOSE INTO AN UPPER LOW OVER NEBRASKA SATURDAY
EVENING AND LIFT INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION LATE
SATURDAY NIGHT INTO SUNDAY. WARM AIR ADVECTION WILL KICK IN SATURDAY
NIGHT AHEAD OF THE APPROACHING LOW. TEMPERATURES SHOULD REMAIN
NEARLY STEADY DURING THE EVENING THEN SLOWLY RISE OVERNIGHT. 07.00
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SUNDAY INTO SUNDAY
NIGHT TAKING THE POTENT LOW OVER OVER CENTRAL MINNESOTA INTO
NORTHWEST WISCONSIN. STRONG LIFT AND WARM AIR ADVECTION WILL MOVE
INTO THE FORECAST AREA AHEAD OF THE LOW LATE SATURDAY NIGHT INTO
SUNDAY MORNING. PRECIPITATION IS EXPECTED TO START OUT AS A
SNOW/SLEET MIX SWITCHING OVER TO FREEZING RAIN THEN EVENTUALLY OVER
TO RAIN LATE IN THE NIGHT AS WARM AIR SURGES IN. SURFACE
TEMPERATURES WILL BE COLD ENOUGH THAT THE RAIN WILL FREEZE UPON
CONTACT EVEN THOUGH AIR TEMPERATURES ARE WARMING ABOVE FREEZING.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
344 AM CST THU FEB 7 2013
PRECIPITATION WILL SWITCH OVER TO MAINLY RAIN SUNDAY AFTERNOON AS
THE LOW MOVES INTO NORTHWEST WISCONSIN. THE LOW IS EXPECTED TO
MOVE INTO NORTHEAST WISCONSIN SUNDAY NIGHT WITH COLDER AIR
WRAPPING INTO THE AREA ON THE BACK SIDE OF THE LOW. PRECIPITATION
WILL SWITCH OVER TO SNOW AS THE LOW LIFTS NORTHEAST. A TRAILING
TROUGH WILL LINGER OVER THE REGION ON MONDAY AS THE LOW CONTINUES
ITS NORTHEAST MOVEMENT INTO EASTERN UPPER MICHIGAN. SNOW CHANCES
WILL CONTINUE THROUGH THE DAY ON MONDAY AS THE TROUGH DRIFTS
THROUGH THE AREA. WEAK HIGH PRESSURE IS EXPECTED TO BUILD INTO THE
REGION TUESDAY INTO WEDNESDAY BRINGING DRY AND QUIET WEATHER TO
THE AREA. PLAN ON HIGHS IN THE LOWER 20S TO AROUND 30 ON
TUESDAY...WARMING SLIGHTLY INTO THE UPPER 20S TO LOWER 30S BY
WEDNESDAY.
&&
.AVIATION...THROUGH 18Z FRIDAY
1120 AM CST THU FEB 7 2013
MAIN FORECAST CONCERNS THROUGH THE TAF PERIOD IS THE LIFR
CONDITIONS OCCURRING AT RST TAF SITE. LATEST VISIBLE SATELLITE
IMAGERY INDICATING LOW STRATUS CLOUD DECK ENCOMPASSING THE UPPER
MIDWEST REGION WITH 17Z METAR OBSERVATIONS REPORTING CEILING
HEIGHTS FROM TWO HUNDRED FEET TO 1100 FEET ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND WESTERN WISCONSIN. THE 07.15Z RAP AND
07.12Z GFS/NAM BUFKIT SOUNDINGS INDICATING THE NEAR SURFACE
BOUNDARY LAYER TO REMAIN SATURATED THROUGH THE OVERNIGHT
HOURS...EXPECT LOW CEILINGS AND LIFR CONDITIONS TO PREVAIL AT RST
THROUGH 02Z FRIDAY AND IFR CONDITIONS THROUGH 09Z FRIDAY...LSE
SHOULD EXPERIENCE MVFR CONDITIONS THROUGH 10Z FRIDAY. HIGH
PRESSURE WILL BUILD INTO WESTERN WISCONSIN AND EASTERN MINNESOTA
AFTER 10Z FRIDAY AND ALLOW FOR DRIER AIR TO ADVECT INTO THE AREA.
WITH THIS...LOW STRATUS DECK WILL ERODE AND VFR CONDITIONS SHOULD
PREVAIL AT BOTH RST AND LSE TAF SITES AFTER 09Z-10Z FRIDAY.
FREEZING DRIZZLE OR LIGHT SNOW IS POSSIBLE AT BOTH TAF SITES
THROUGH EARLY THIS EVENING...HOWEVER PRECIPITATION WILL REMAIN
VERY LIGHT AND HAVE KEPT OUT OF TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
344 AM CST THU FEB 7 2013
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ017-
029-032>034-041>044-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...DTJ