Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/04/13
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
640 PM EST SUN MAR 3 2013
.SYNOPSIS...
LOW PRESSURE MOVING WEST ONTO NOVA SCOTIA THIS EVENING WILL TURN
SOUTHEAST OUT TO SEA...TO THE SOUTH OF NOVA SCOTIA LATE MONDAY.
LOW PRESSURE OVER KENTUCKY TUESDAY WILL SLOWLY INTENSIFY AS IT
REDEVELOPS OVER SOUTHEAST VIRGINIA OR NORTHEAST NORTH CAROLINA
WEDNESDAY. IT THEREAFTER HEADS SLOWLY EAST OR NORTHEAST OUT TO
SEA ON THURSDAY, WITH HIGH PRESSURE BUILDING INTO THE MID ATLANTIC
STATES FRIDAY AND SATURDAY. A WEAK COLD FRONT MAY CROSS THE REGION
LATE SATURDAY OR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE PERSISTENT UPPER-LEVEL TROUGH ACROSS THE EASTERN U.S. WILL BE
ENHANCED SOME TONIGHT AS A STRONG SHORT WAVE DIVES SOUTHEASTWARD
DOWN THE WESTERN SIDE. AS THIS FEATURE SLIDES MOSTLY TO OUR SOUTH
LATE TONIGHT, THE CLOSED LOW AND ASSOCIATED SURFACE LOW NEAR NOVA
SCOTIA IS FORECAST TO RETROGRADE SOME. THIS IS ALREADY OCCURRING
AS WATER VAPOR IMAGERY SUGGESTS, WHICH IS A RESULT OF A BLOCKING
PATTERN. PRIOR TO THIS THOUGH, OUR SENSIBLE WEATHER IS DRIVEN BY
AN AIRMASS THAT IS QUITE COLD ESPECIALLY ALOFT WITH 500 MB
TEMPERATURES NEAR -27C. THIS RESULTED IN A WEALTH OF STRATOCUMULUS
ACROSS THE AREA, HOWEVER SOME DRYING HAS BEEN EVIDENT WITH DEW
POINTS DROPPING SOME AND ALSO SOME HOLES OPENING UP ACROSS NEW
JERSEY. THE FORECAST SOUNDINGS SUGGEST THAT WHILE SOME ADDITIONAL
THINNING COULD OCCUR THROUGH TONIGHT, A MORE PRONOUNCED LOW-LEVEL
INVERSION LOWERS SOME. WHILE SOME ADDITIONAL DRYING TENDS TO
OCCUR, WHATEVER MOISTURE IS LEFT WOULD TEND TO GET TRAPPED UNDER
THIS. THE NAM IS MORE ROBUST WITH THIS SCENARIO, HOWEVER GIVEN THE
PATTERN WE ARE IN, THE CLOUDS PROBABLY WILL THIN OUT SOME MORE FOR
A TIME. WE TRIED TO LEAN IN THIS DIRECTION ESPECIALLY THE FARTHER
EAST AND SOUTH ONE GOES ACROSS THE CWA.
THE CYCLONIC FLOW AND LINGERING PVA HAS PRODUCED SOME FLURRIES,
ALTHOUGH THIS APPEARS TO BE MORE FOCUSED ACROSS THE FAR NORTHWEST
ZONES NOW. THEREFORE, WE WILL CONTINUE WITH SOME FLURRIES THERE
THROUGH THE NIGHT. INTERESTINGLY ENOUGH SOME OF THE HIGH RESOLUTION
GUIDANCE, SUCH AS THE HRRR AND SPC WRF, SUGGEST SOME FLURRIES OR A
NARROW STREAMER OR TWO OF SNOW SHOWERS ARRIVES MAINLY DURING THE
COURSE OF THIS EVENING. THESE ARE TOUGH TO FORECAST AND WHILE WE
CANNOT RULE IT OUT GIVEN THE SHORT WAVE ENERGY, WE LEFT IT OUT ATTM
DUE TO LOW CONFIDENCE.
A TIGHTENED PRESSURE GRADIENT REMAINS, HOWEVER IT APPEARS THAT THE
VERTICAL MIXING HAS PEAKED. WE WILL STILL HAVE BRISK CONDITIONS FOR
MOST LOCALES INTO THIS EVENING AS SOME GUSTS REACH TO NEAR 25 MPH.
THIS VERTICAL MIXING LOOKS TO GENERALLY DECOUPLE FOR MANY LOCALES
THIS EVENING BEFORE AN UPTICK MAY OCCUR AGAIN. AS THE AFOREMENTIONED
SHORT WAVE AMPLIFIES THE MAIN TROUGH FOR A TIME TONIGHT, THE
PRESSURE GRADIENT IS FORECAST TO TIGHTEN SOME MORE OVERNIGHT. THE
FORECAST SOUNDINGS SUGGEST THAT THE MIXING STARTS TO INCREASE ONCE
AGAIN LATE TONIGHT, THEREFORE THE SURFACE WINDS MAY START TO
RESPOND. THEREFORE, WE TRIED TO DEPICT THIS IN THE GRIDDED DATABASE.
AS FOR LOW TEMPERATURES, WE GENERALLY USED A MOS BLEND WITH JUST
SOME MINOR ADJUSTMENTS. IT WILL BE A RATHER COLD NIGHT, HOWEVER IF
THE WIND PICKS UP AGAIN /OR HOLDS UP ENOUGH/ THEN THIS MAY KEEP THE
AIR TEMPERATURES A BIT HIGHER.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
A BLOCKING PATTERN IS MAINTAINED WITH A CLOSED LOW TENDING TO DRIFT
SOUTHWESTWARD SOME FROM NOVA SCOTIA. A SIGNIFICANT SHORT WAVE THAT
ROTATES UNDERNEATH THIS MAIN UPPER-LEVEL TROUGH LOOKS TO PULL THE
MAIN PORTION OF THE TROUGH TO OUR EAST BY THE END OF THE DAY. AS
THIS OCCURS, OUR REGION REMAINS WITHIN A CYCLONIC FLOW REGIME WITH
EMBEDDED SHORT WAVES STILL MOVING OVERHEAD WITH THE STRONG
NORTHWESTERLY FLOW. THESE SHORT WAVES ARE FORECAST TO BECOME MORE
CHANNELIZED THROUGH THE DAY.
THE FORECAST SOUNDINGS OVERALL SHOW SOMEWHAT DRIER AIR IN PLACE,
WHICH WOULD SUGGEST LESS IN THE WAY OF CLOUDS. SINCE THE CORE OF THE
UPPER-LEVEL TROUGH IS FORECAST TO BE SHIFTING TO OUR EAST, WE WILL
PROBABLY LOSE SOME OF THE THERMAL DIFFERENTIAL FROM THE SURFACE TO
ALOFT. IF THIS IS THE CASE, THE CLOUDS MAY NOT FILL IN AS MUCH.
GIVEN THE CLOSE PROXIMITY OF THE MAIN UPPER-LEVEL TROUGH AND
CYCLONIC FLOW PRESENT, WE STILL CARRIED A FAIR AMOUNT OF CLOUDS. THE
GREATEST IS ACROSS THE NORTHWEST ZONES GIVEN THE COLD FLOW OFF THE
LAKES. WE ALSO CARRIED FLURRIES IN THE POCONOS WITH THIS NORTHWEST
FLOW AND SOME GUIDANCE SUGGESTING SOME LAKE ONTARIO ACTIVITY MAKES
IT INTO NORTHEAST PENNSYLVANIA. THE 850 MB TEMPERATURES ARE FORECAST
TO MODERATE THROUGH THE DAY, SO THIS MAY ALSO KEEP THE CLOUD COVER A
BIT LESS.
AS THE ENTIRE CLOSED LOW RETROGRADES SOME, THE PRESSURE GRADIENT,
ASSOCIATED WITH THE SURFACE LOW TO OUR NORTHEAST AND THEN HIGH
PRESSURE IN THE OHIO VALLEY, WILL TIGHTEN. THE FORECAST SOUNDINGS
INDICATE STRONGER FLOW ABOVE THE SURFACE AND THE LOW-LEVEL LAPSE
RATES STEEPENING. THIS LEADS TO DEEPER VERTICAL MIXING AS WE GO
THROUGH THE MORNING AND AFTERNOON. AS A RESULT, WE ARE ANTICIPATING
A BREEZY TO WINDY DAY /PEAK GUSTS NEAR 30 MPH/.
AS FOR TEMPERATURES, WE WENT WITH AN EVEN NAM/GFS BLEND. THE AIRMASS
IS STILL CHILLY DESPITE IT STARTING TO MODERATE ALOFT, THEREFORE WE
LEANED A BIT MORE TOWARD THE COOLER GUIDANCE FOR MANY LOCALES.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
**SUBSTANTIAL LONG DURATION NOREASTER FOR AT LEAST THE SOUTHERN
PORTION OF OUR AREA WEDNESDAY INTO THURSDAY**
DEFERRED ON WATCHES AT THIS TIME SINCE WE`RE FORECAST FOR PERIODS
6-8...72 TO 96 HOURS IN ADVANCE.
THOSE WITH CONCERNS FOR S NJ...DE AND E MD SHORE AND FAR SE PA
WEDNESDAY INTO THURSDAY SHOULD MONITOR LATER STATEMENTS...WATCHES
AND POSSIBLE WARNINGS FOR THE FOLLOWING HAZARDS BEGINNING TOMORROW
MORNING:
COASTAL FLOOD...MODERATE OR MAJOR COASTAL FLOOD THREAT FOR THE S
NJ AND ESPECIALLY DELAWARE ATLANTIC COAST. PLEASE SEE TIDE SECTION
FOR MORE DETAILS.
WIND...POTENTIAL HIGH WIND EVENT /60 MPH GUSTS/ FOR COASTAL SOUTHERN
NEW JERSEY AND ESPECIALLY COASTAL DELAWARE WITH WIND ADVISORY
POTENTIAL FOR THE REMAINDER OF SOUTHERN AND CENTRAL DELAWARE...E
MD AND INTERIOR SOUTH THIRD OF NJ POSSIBLY THROUGH PHILADELPHIA
AND SE PA.
SNOW...ESPECIALLY ELEVATIONS. THE BOUNDARY LAYER TEMPERATURE
GOVERNS RAIN/SNOW.
RIGHT NOW THE LOWEST 50 MB ABOVE 0C LAYER IS THE DIFFICULTY ON
CONFIDENTLY FORECASTING A MAJOR WET SNOW. IT IS ANTICIPATED THAT
THERE WILL BE A PERIOD OF HEAVY WET SNOW THAT WILL ACCUMULATE
SEVERAL SLOPPY INCHES IN PARTS OF OUR AREA...ESPECIALLY NORTHERN
DELAWARE AND ADJACENT NE MD AND POSSIBLY SE PA. 06Z-12Z/3 GFS
DENDRITE GROWTH LOOKS TO BE SUBSTANTIAL FOR 12 HOURS WEDNESDAY
OVER E MD AND DE. HOWEVER... ITS FAR TOO EARLY TO BE CONFIDENT ON
AMOUNTS... TIMING AND AREAL COVERAGE. IF THIS RAIN CHANGING TO
HEAVY WET SNOW DOES OCCUR...AND IT LASTS FOR 6 HOURS OR MORE WITH
THE SURFACE TEMP 33F...WE WOULD HAVE A CHANCE FOR POWER OUTAGES
DUE TO WET SNOW ACCRETION ON TREES AND WIRES. AGAIN FAR TOO EARLY.
FOR NOW OUR SNOW GRIDS ARE VERY CONSERVATIVE DUE TO THE SFC TEMPS.
HYDRO...NO CONCERNS EXCEPT FOR PERIODS OF NUISANCE POOR DRAINAGE
FLOODING...PROVIDED THE AXIS OF 1 TO 3 INCHES OF RAIN DOES NOT
CREEP NORTH OF WILMINGTON.
OVERALL PATTERN THIS FORECAST PERIOD: BLOCKING PATTERN IN NORTHEAST
CANADA SLOWLY ERODES BY THE END OF THE WEEK. THE PRIMARY SHORTWAVE
IS ALREADY CLOSING OFF OVER THE DAKOTAS MONDAY EVENING ARRIVING OVER
NORTHEAST NORTH CAROLINA OR SOUTHEAST VIRGINIA WEDNESDAY. IT THEN
HEADS SLOWLY EAST OUT TO SEA AND WEAKENS BY FRIDAY AS RIDGING DEVELOPS
ALONG THE EAST COAST. WEAK TROUGHING REPLACES THE PREVIOUS BLOCK
OVER NORTHEAST CANADA BY SUNDAY WHILE A NEW LARGE SCALE CLOSED LOW
DRIFTS EAST INTO THE SOUTHERN AND CENTRAL PLAINS.
CALENDAR DAY AVERAGE TEMPS: NEAR OR A BIT BELOW NORMAL TUESDAY AND
WEDNESDAY THEN SLOWLY WARMING ABOVE NORMAL SO THAT BY FRIDAY...
SATURDAY AND SUNDAY TEMPS MAY BE AVERAGING ALMOST 5 DEGREES ABOVE
NORMAL.
THE DAILIES BELOW...
STATISTICAL GUIDANCE GOVERNING THIS FORECAST WAS A BLEND OF THE
12Z/3 GFS/NAM MOS THROUGH TUE NIGHT...THEN THE GFS MEX MOS WED
THROUGH THURSDAY WITH SOME COLDER 2M TEMP BLENDING. FOR THURSDAY NIGHT
AND BEYOND...RELIED SOLELY ON 15Z/3 HPC GUIDANCE UNLESS OTHERWISE
NOTED. HAVE NOT SPENT MUCH TIME ADJUSTING THE HPC FORECAST FOR THE
PERIOD THURSDAY NIGHT THROUGH SUNDAY WITH ANY ADJUSTMENTS FOCUSED
IN THE TUE NIGHT-THU AFTERNOON TIME FRAME...ESPECIALLY SINCE THE
12Z ECMWF OP HIGH RES RUN DID NOT ARRIVE IN TIME FOR DIRECT
INCLUSION INTO THE FORECAST.
THE DAILIES BELOW...
MONDAY NIGHT AND TUESDAY...FAIR SEASONABLY COOL WEATHER WITH
DIMINISHING NW WIND GUSTS OF 20-25 MPH MONDAY EVENING BECOMING LIGHT
NORTH OR NORTHEAST TUESDAY AFTERNOON.
TUESDAY NIGHT...INCREASING AND THICKENING CLOUDS. CHANCE OF SNOW OR
PRECIPITATION LATE. CONSERVATIVE FORECAST WITH BLENDED 12Z/3 NCEP
MOS GUIDANCE. WE DID NOTE THE UKMET DROPPING .04 DOWN INTO NE NJ
SEPARATELY FROM THE ONCOMING MID ATLANTIC CLOSED LOW BUT DID NOT
PLAY THIS UP. IN ANY CASE...A COVERING OF SNOW IS POSSIBLE BY
DAYBREAK WEDNESDAY BUT DIDNT PLAY THIS UP DUE TO ONSET OF PCPN
TIMING ISSUE AND PTYPE/SFC TEMP. PLEASE MONITOR LATER FORECASTS.
IT COULD BE A SLIPPERY START TO WEDNESDAY IN SE PA AND NE MD.
WEDNESDAY...STORMY OVER THE SRN PART OF THE AREA. PLAYED THIS
MOSTLY AS RAIN DUE TO THE ABOVE FREEZING BOUNDARY LAYER BUT IT
COULD BE A CLOSE CALL IN PARTS OF MD WESTERN DELAWARE AND SE PA.
LONG WAYS TO GO...SO WE CAN TRY TO IRON OUT EXPECTATIONS AS WE
DRAW CLOSER TO THE EVENT. 12Z/3 NCEP GUIDANCE POPS WERE TRIMMED
IN NE PA AND NNJ RESPECTING THE SOUTHWARD ECMWF/UKMET CAMP. COULD
BE A SHARP CUTOFF ON THE NRN EDGE GOING FROM NO PCPN TO OVER HALF
AN INCH IN 50 MILES. ALSO CONCERNED ABOUT 60 MPH WIND GUSTS IN DE
AND FAR SE NJ.
SO...A MULTI HAZARD DAY. WIND...COASTAL FLOODING...POSSIBLY SNOW
AND POOR DRAINAGE FLOODING...MOSTLY DE/MD/S NJ AND FAR SE PA.
PLEASE NOTE THE FORECAST WORDING IN SOME OF THE ZONES IS LESS THAN
DETERMINISTICALLY IDEAL BUT WHERE ITS COMPLEX...ALSO STATES WHERE
THERE IS GREATER UNCERTAINTY AS TO THE PTYPE.
THURSDAY...SLOW CLEARING FM WEST TO EAST...TIMING OF THIS PROCESS
UNCERTAIN AT THIS TIME. WINDY NORTHERLY FLOW WITH GUSTS 25 TO 35
MPH.
THURSDAY NIGHT-SUNDAY...GENERALLY FAIR WEATHER EXPECTED WITH
GUSTY NORTH NORTHWEST WINDS OF 20 TO 25 MPH THROUGH FRIDAY
BECOMING LIGHT SATURDAY. HPC GUIDANCE FOLLOWED CLOSELY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR. THE CEILINGS THINNING OUT SHOULD FILL BACK IN,
ESPECIALLY NORTH AND WEST OF THE KPHL METRO AREA. NORTHWEST
WINDS AROUND 10 KNOTS, HOWEVER SOME GUSTS MAY OCCUR AGAIN ESPECIALLY
LATE.
MONDAY...VFR. NORTHWEST WINDS 15-20 WITH GUSTS TO AROUND 25 KNOTS.
OUTLOOK...
MON NIGHT...VFR EXCEPT POSSIBLE MVFR CIGS VCNTY KMPO CLEARING LATE.
NW WIND GUST 15-25 KTS TO BEGIN THE EVENING...THEN DIMINISHING.
HIGH CONFIDENCE.
TUESDAY...VFR. LIGHT NORTH WIND BECOMING NORTHEAST. HIGH CONFIDENCE.
TUESDAY NIGHT...CONDS MAY LOWER TO MVFR IF PRECIPITATION DEVELOPS
LATE. INCREASING NE WIND LATE. BELOW AVERAGE CONFIDENCE ON DETAILS.
WED...MVFR OR IFR CONDS IN RAIN OCCASIONALLY CHANGING TO SNOW...ESPECIALLY
KPHL SOUTH. NE WIND SHOULD GENERALLY GUST 25-35 KTS DURING THE DAY
AND EVENING WITH HIGHER GUSTS TO 45 KNOTS ALONG THE COAST. AVERAGE
CONFIDENCE.
THU...ANY SUB VFR CONDITIONS EARLY...IMPROVING TO VFR. NNW WIND G
25-35 KTS DURING THE DAY. AVERAGE CONFIDENCE.
FRI...VFR. NNW WIND G20-25 KTS DURING THE DAY. HIGH CONFIDENCE.
&&
.MARINE...
A TIGHT ENOUGH PRESSURE COMBINED WITH A COLD AIRMASS IS MAINTAINING
ENOUGH VERTICAL MIXING. THE NORTHWEST FLOW IS ALIGNED ENOUGH TO
FUNNEL DOWN THE LENGTH OF DELAWARE BAY. THIS HAS RESULTED IN GUSTS
TO AROUND 25 KNOTS ESPECIALLY AROUND THE BAY MOUTH. THE FORECAST
SOUNDINGS INDICATE THAT THE FLOW INCREASES SOME THROUGH THE NIGHT,
WITH THE LOW-LEVEL LAPSE RATES STEEPENING. AS THIS OCCURS, THE
MIXING SHOULD DEEPEN A BIT MORE ACROSS ALL OF OUR WATERS. AS A
RESULT, THE SMALL CRAFT ADVISORY IS IN EFFECT THROUGH TONIGHT. THE
STRONG NORTHWEST FLOW AND CHILLY AIRMASS IS EXPECTED TO MAINTAIN
DEEPER MIXING MONDAY AS WELL, THUS THE PREVIOUSLY ISSUED ADVISORY
REMAINS IN EFFECT THROUGH THE DAY MONDAY. SEAS 2-4 FEET SHOULD
INCREASE A LITTLE MORE DUE TO THE UPTICK IN THE WINDS, HOWEVER GIVEN
THE OFFSHORE FLOW, THE HIGHEST SEAS SHOULD BE FARTHER OFFSHORE AND
IN LOWER DELAWARE BAY AND THROUGH THE BAY MOUTH.
OUTLOOK...
SCA WAS EXTENDED TIL ABOUT MIDNIGHT MONDAY NIGHT FOR LEFTOVER NW
FLOW GUSTS TO 25 OR 30 KT. SOME OF THE GUIDANCE SUGGESTS SCT 35 KT
GUSTS NJ AND DE BAY ENTRANCE MONDAY EVENING.
TUESDAY...NO HEADLINE ANTICIPATED AS WINDS DIMINISH AND BECOMING
LIGHT NORTH. NE WINDS INCREASE LATE TUE NIGHT.
WEDNESDAY INTO THURSDAY...AT A MINIMUM A GALE WARNING. A GOOD CHANCE
WE`LL NEED A STORM WARNING...ESPECIALLY VCNTY CAPE MAY SOUTHWARD.
SEAS TO AT LEAST 15 FEET OFF THE SNJ AND DE COAST WITH POSSIBLE 20
FT AT THE 44009 BUOY.
PRIMARY THREAT FOR STRONGEST WIND APPEARS TO BE CENTERED WEDNESDAY
EVENING WITHIN SEVERAL HOURS OF 7 PM.
FRIDAY...ATLC WATERS AN SCA FOR LEFTOVER NE SWELL OF 5 TO 8 FEET AND
13 SECONDS. DE WATERS MIGHT NEED AN SCA FOR WIND GUSTS.
&&
.TIDES/COASTAL FLOODING...
EXPECTING A WATCH WILL BE NEEDED FOR MULTIPLE TIDE CYCLES ALONG
THE ATLC COAST WED AFTERNOON AND THURSDAY MORNING HIGH TIDES...
ESPECIALLY ATLANTIC CITY SOUTH. EVEN THE TIDAL DELAWARE WILL
PROBABLY NEED AN ADVISORY FOR THE WED EVENING AND THURSDAY
DAYBREAK HIGH TIDE CYCLES.
SURGE OF NEARLY 4 FEET IS EXPECTED WITH THE PRIMARY DANGER PERIOD
THE EARLY THURSDAY MORNING HIGH TIDE CYCLE ALONG THE ATLANTIC
COAST...ESPECIALLY DELAWARE. SEAS OF 15 FEET ARE PROBABLY POUNDING
THE DELAWARE COAST WITH WIND GUSTS TO AT LEAST 50 MPH WEDNESDAY
NIGHT. HOWEVER...SINCE THE MODELS ARE TRENDING A BIT FASTER... ITS
YET POSSIBLE THE THE WEDNESDAY AFTERNOON STORM TIDE WILL EQUAL THAT
OF THURSDAY MORNING.
SURGE AT LOW AND HIGH TIDE WEDNESDAY NIGHT ON THE ATLANTIC WATERS
NEAR OR AROUND 4 FEET...WHICH COMBINED WITH POSSIBLE HEAVY
RAINFALL...COULD MEAN TIDAL INUNDATION FLOODING OF ABOUT 3 HOURS
EITHER SIDE OF THE THE HIGH TIDE.
A SURGE OF 3.6 FEET WEDNESDAY AFTERNOON AND 2.5 FEET THURSDAY
MORNING WOULD REACH THE THRESHOLD OF MDT COASTAL FLOODING WHICH
SEEMS ALMOST A CERTAINTY IN DELAWARE. ADD A FOOT FOR MAJOR WHICH IS
A LOWER RISK BUT QUITE POSSIBLE AND ALREADY MODELED BY A RATHER
STRONG 12Z GFS CYCLE. IF FUTURE MODEL RUNS ARE WEAKER...THEN THE
SURGE AND CONSEQUENT POTENTIAL FOR A MAJOR COASTAL FLOOD EVENT
WOULD BE LESS.
ALL OF THIS IS IMPORTANT...PARTLY BECAUSE OF OF THE DAMAGE
INCURRED WITH SANDY THIS PAST OCTOBER BUT ALSO SINCE SOME OF MODEL
GUIDANCE IS OUTLOOKING ABOUT THE 3RD OR 4TH HIGHEST STORM TIDE ON
RECORD FOR LEWES. THAT VALUE IS NOT A DONE DEAL BUT ITS IN THE MIX
OF POSSIBILITIES.
HERE ARE THE TIMES OF HIGH TIDE AND THE FORECAST ASTRONOMICAL TIDE
HEIGHTS FOR SELECTED POINTS ALONG THE COAST. THE FORECAST
ASTRONOMICAL TIDE HEIGHT PLUS THE ACTUAL STORM SURGE WILL EQUAL THE
ACTUAL WATER LEVEL AT THE TIME OF HIGH TIDE.
ALL HEIGHTS ARE IN MEAN LOWER LOW WATER (MLLW).
WEDNESDAY THURSDAY
REHOBOTH BEACH DE 3.2 FT AT 250 PM 4.2 FT AT 335 AM
LEWES DE 3.6 FT AT 355 PM 4.6 FT AT 434 AM
CAPE MAY NJ (OCEANFRONT) 3.8 FT AT 319 PM 5.0 FT AT 354 AM
ATLANTIC CITY NJ 3.4 FT AT 245 PM 4.5 FT AT 320 AM
SEASIDE HEIGHTS NJ (OCEANFRONT) 4.0 FT AT 228 PM 4.7 FT AT 301 AM
SANDY HOOK NJ 4.3 FT AT 258 PM 5.1 FT AT 331 AM
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...DRAG
AVIATION...DRAG/GORSE/HEAVENER
MARINE...DRAG/GORSE
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1205 PM CST SAT MAR 2 2013
.DISCUSSION...
ISSUED 1049 AM CST SAT MAR 2 2013
NORTHERLY WINDS MOVING IN OVER THE FA WITH A NARROW RIDGE OF HIGH
PRESSURE JUST TO THE WEST OF THE MISS RIVER VALLEY SLOWLY
ADVANCING INTO THE MIDWEST. PERSISTENT CLOUDS FROM THE LAST FEW
DAYS SLOWLY RETREATING WEST TO EAST THIS MORNING. HAVE MADE A FEW
TWEAKS TO THE FORECAST FOR THE END TO THE FLURRIES FOR THE
AFTERNOON...THE RETREAT OF THE CLOUDS AND SOME MINOR UPDATES TO
THE HOURLY TEMPS. ALL IN ALL...NO MAJOR ADJUSTMENTS TO THE SHORT
TERM...AND NO ZONE UPDATES ARE NECESSARY AT THIS TIME.
&&
.AVIATION...
ISSUED 1202 PM CST SAT MAR 2 2013
SFC RIDGE SLOWLY ADVANCING INTO THE MISS RIVER VALLEY...N/NWRLY
WINDS DOMINATING...BUT WILL LIGHTEN IN THE OVERNIGHT HOURS.
CLEARING THE STRATUS THIS AFTERNOON FROM WEST TO EAST FOR ILX
TERMINALS. SCT CIRRUS WILL REMAIN...AND SOME MID LEVEL MOISTURE
COULD RESULT IN SOME SCT MID LEVEL CLOUDS AFTER MIDNIGHT. LIGHTER
WINDS IN THE OVERNIGHT AND SOME EFFICIENT RADIATIONAL COOLING MAY
ADD TO THE THREAT FOR SOME MINOR VIS REDUCTIONS FOR PIA AND BMI.
WILL WATCH THIS AFTERNOONS XOVER TEMPS FOR ADDING IN A FEW HOURS
TOWARDS DAWN IF NECESSARY.
HJS
&&
.PREV DISCUSSION...
ISSUED 240 AM CST SAT MAR 2 2013
PESKY LONG-LASTING LIGHT SNOW IS FINALLY BEGINNING TO EXIT THE
AREA...AND WAS MAINLY SOUTH OF I-70 EARLY THIS MORNING. LOW CLOUD
DECK HAS BEEN ERODING FROM THE NORTH AND SOME BREAKS HAVE
DEVELOPED AS FAR SOUTH AS PEORIA...BUT STILL PLENTY OF CLOUDINESS
OVER THE AREA.
MAIN FORECAST CONCERNS INVOLVE PRECIPITATION CHANCES EARLY NEXT
WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
MOSTLY DRY CONDITIONS EXPECTED TODAY FOR A CHANGE. WILL NEED TO
MONITOR FOR SOME LINGERING LIGHT SNOW SHOWERS ACROSS THE EASTERN
CWA TODAY...ESPECIALLY WITH THE WIND TRAJECTORY COMING OFF LAKE
MICHIGAN. CLOUDS MAY BE A BIT SLOWER TO ERODE...WITH 925-850 MB
HUMIDITY PLOT OFF THE RAP MODEL KEEPING A FAIR AMOUNT OF
CLOUDINESS EAST OF I-55 WELL INTO THE AFTERNOON. HOWEVER...
CLEARING LATER TODAY AND TONIGHT WILL PRECEDE A RIDGE OF HIGH
PRESSURE THAT WILL CROSS THE STATE ON SUNDAY.
DEEP UPPER TROUGHING OVER THE EASTERN U.S. TO PUSH EASTWARD ON
SUNDAY...AS A SHORTWAVE IN SOUTHWEST CANADA BEGINS TO CLOSE OFF
AND DROP INTO THE NORTHERN PLAINS EARLY NEXT WEEK. PRECIP CHANCES
EARLY NEXT WEEK WILL FOCUS ON A COUPLE FEATURES. THE FIRST WILL BE
WITH THE STRONG WARM AIR ADVECTION THAT WILL TAKE PLACE LATE
SUNDAY NIGHT...WITH EVENING MODELS IN FAIRLY GOOD AGREEMENT IN
DEVELOPMENT OF SOME LIGHT SNOW ACROSS THE WESTERN CWA AFTER
MIDNIGHT...AND SPREADING OVER MUCH OF THE CWA ON MONDAY. SHOULD
SEE SOME TRANSITION OVER TO RAIN DURING THE DAY ACROSS THE SOUTH
HALF OF THE FORECAST AREA...AS TEMPERATURES RISE TO AROUND THE 40
DEGREE MARK. SECOND FOCUS WILL BE AS LOW PRESSURE DEVELOPS OVER
THE CENTRAL PLAINS AND TOWARD THE WESTERN OHIO VALLEY BY TUESDAY
MORNING...WITH AN INVERTED SURFACE TROUGH EXTENDING NORTHWEST
TOWARD THE UPPER LOW. HAVE MAINTAINED HEALTHY PRECIP CHANCES
THROUGH TUESDAY WITH THESE FEATURES...MOSTLY AS SNOW BUT WITH SOME
RAIN ACROSS THE SOUTHEAST. POTENTIAL EXISTS FOR ANOTHER 1 TO 3
INCHES OF SNOW EARLY NEXT WEEK.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
UPPER LOW SHOULD MAKE SOME STEADY PROGRESS SOUTHEAST AND FORM A
STRONG STORM SYSTEM OFF THE CAROLINA COAST BY MIDWEEK. THIS WILL
ALLOW FOR SOME UPPER RIDGING ACROSS THE CENTER OF THE NATION...
WITH MODERATING TEMPERATURES AS A SOUTHWEST UPPER FLOW SETS UP
LATER IN THE WEEK...AND HIGHS ARE LIKELY TO RETURN TO THE 50S BY
FRIDAY. ANY PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL NEXT
WEEKEND...BEYOND THE CURRENT FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1052 AM CST SAT MAR 2 2013
.DISCUSSION...
ISSUED 1049 AM CST SAT MAR 2 2013
NORTHERLY WINDS MOVING IN OVER THE FA WITH A NARROW RIDGE OF HIGH
PRESSURE JUST TO THE WEST OF THE MISS RIVER VALLEY SLOWLY
ADVANCING INTO THE MIDWEST. PERSISTENT CLOUDS FROM THE LAST FEW
DAYS SLOWLY RETREATING WEST TO EAST THIS MORNING. HAVE MADE A FEW
TWEAKS TO THE FORECAST FOR THE END TO THE FLURRIES FOR THE
AFTERNOON...THE RETREAT OF THE CLOUDS AND SOME MINOR UPDATES TO
THE HOURLY TEMPS. ALL IN ALL...NO MAJOR ADJUSTMENTS TO THE SHORT
TERM...AND NO ZONE UPDATES ARE NECESSARY AT THIS TIME.
HJS
&&
.AVIATION...
ISSUED 556 AM CST SAT MAR 2 2013
PREDOMINANTLY VFR CONDITIONS EXPECTED ACROSS THE CENTRAL ILLINOIS
TERMINALS THROUGH THE 12Z TAF VALID TIME. THE PERSISTENT AREA OF
LOW CLOUDINESS...AS WELL AS A FEW FLURRIES...WILL GRADUALLY MOVE
OUT OF THE AREA TODAY AS HIGH PRESSURE STARTS TO BUILD ACROSS THE
TERMINALS. NORTHERLY WINDS TO THE EAST OF THE RIDGE AXIS SHOULD
TREND LIGHT/VARIABLE TONIGHT WITH THE APPROACH OF THE RIDGE.
BAK
&&
.PREV DISCUSSION...
ISSUED 240 AM CST SAT MAR 2 2013
PESKY LONG-LASTING LIGHT SNOW IS FINALLY BEGINNING TO EXIT THE
AREA...AND WAS MAINLY SOUTH OF I-70 EARLY THIS MORNING. LOW CLOUD
DECK HAS BEEN ERODING FROM THE NORTH AND SOME BREAKS HAVE
DEVELOPED AS FAR SOUTH AS PEORIA...BUT STILL PLENTY OF CLOUDINESS
OVER THE AREA.
MAIN FORECAST CONCERNS INVOLVE PRECIPITATION CHANCES EARLY NEXT
WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
MOSTLY DRY CONDITIONS EXPECTED TODAY FOR A CHANGE. WILL NEED TO
MONITOR FOR SOME LINGERING LIGHT SNOW SHOWERS ACROSS THE EASTERN
CWA TODAY...ESPECIALLY WITH THE WIND TRAJECTORY COMING OFF LAKE
MICHIGAN. CLOUDS MAY BE A BIT SLOWER TO ERODE...WITH 925-850 MB
HUMIDITY PLOT OFF THE RAP MODEL KEEPING A FAIR AMOUNT OF
CLOUDINESS EAST OF I-55 WELL INTO THE AFTERNOON. HOWEVER...
CLEARING LATER TODAY AND TONIGHT WILL PRECEDE A RIDGE OF HIGH
PRESSURE THAT WILL CROSS THE STATE ON SUNDAY.
DEEP UPPER TROUGHING OVER THE EASTERN U.S. TO PUSH EASTWARD ON
SUNDAY...AS A SHORTWAVE IN SOUTHWEST CANADA BEGINS TO CLOSE OFF
AND DROP INTO THE NORTHERN PLAINS EARLY NEXT WEEK. PRECIP CHANCES
EARLY NEXT WEEK WILL FOCUS ON A COUPLE FEATURES. THE FIRST WILL BE
WITH THE STRONG WARM AIR ADVECTION THAT WILL TAKE PLACE LATE
SUNDAY NIGHT...WITH EVENING MODELS IN FAIRLY GOOD AGREEMENT IN
DEVELOPMENT OF SOME LIGHT SNOW ACROSS THE WESTERN CWA AFTER
MIDNIGHT...AND SPREADING OVER MUCH OF THE CWA ON MONDAY. SHOULD
SEE SOME TRANSITION OVER TO RAIN DURING THE DAY ACROSS THE SOUTH
HALF OF THE FORECAST AREA...AS TEMPERATURES RISE TO AROUND THE 40
DEGREE MARK. SECOND FOCUS WILL BE AS LOW PRESSURE DEVELOPS OVER
THE CENTRAL PLAINS AND TOWARD THE WESTERN OHIO VALLEY BY TUESDAY
MORNING...WITH AN INVERTED SURFACE TROUGH EXTENDING NORTHWEST
TOWARD THE UPPER LOW. HAVE MAINTAINED HEALTHY PRECIP CHANCES
THROUGH TUESDAY WITH THESE FEATURES...MOSTLY AS SNOW BUT WITH SOME
RAIN ACROSS THE SOUTHEAST. POTENTIAL EXISTS FOR ANOTHER 1 TO 3
INCHES OF SNOW EARLY NEXT WEEK.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
UPPER LOW SHOULD MAKE SOME STEADY PROGRESS SOUTHEAST AND FORM A
STRONG STORM SYSTEM OFF THE CAROLINA COAST BY MIDWEEK. THIS WILL
ALLOW FOR SOME UPPER RIDGING ACROSS THE CENTER OF THE NATION...
WITH MODERATING TEMPERATURES AS A SOUTHWEST UPPER FLOW SETS UP
LATER IN THE WEEK...AND HIGHS ARE LIKELY TO RETURN TO THE 50S BY
FRIDAY. ANY PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL NEXT
WEEKEND...BEYOND THE CURRENT FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
556 AM CST SAT MAR 2 2013
.DISCUSSION...
ISSUED 240 AM CST SAT MAR 2 2013
PESKY LONG-LASTING LIGHT SNOW IS FINALLY BEGINNING TO EXIT THE
AREA...AND WAS MAINLY SOUTH OF I-70 EARLY THIS MORNING. LOW CLOUD
DECK HAS BEEN ERODING FROM THE NORTH AND SOME BREAKS HAVE
DEVELOPED AS FAR SOUTH AS PEORIA...BUT STILL PLENTY OF CLOUDINESS
OVER THE AREA.
MAIN FORECAST CONCERNS INVOLVE PRECIPITATION CHANCES EARLY NEXT
WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
MOSTLY DRY CONDITIONS EXPECTED TODAY FOR A CHANGE. WILL NEED TO
MONITOR FOR SOME LINGERING LIGHT SNOW SHOWERS ACROSS THE EASTERN
CWA TODAY...ESPECIALLY WITH THE WIND TRAJECTORY COMING OFF LAKE
MICHIGAN. CLOUDS MAY BE A BIT SLOWER TO ERODE...WITH 925-850 MB
HUMIDITY PLOT OFF THE RAP MODEL KEEPING A FAIR AMOUNT OF
CLOUDINESS EAST OF I-55 WELL INTO THE AFTERNOON. HOWEVER...
CLEARING LATER TODAY AND TONIGHT WILL PRECEDE A RIDGE OF HIGH
PRESSURE THAT WILL CROSS THE STATE ON SUNDAY.
DEEP UPPER TROUGHING OVER THE EASTERN U.S. TO PUSH EASTWARD ON
SUNDAY...AS A SHORTWAVE IN SOUTHWEST CANADA BEGINS TO CLOSE OFF
AND DROP INTO THE NORTHERN PLAINS EARLY NEXT WEEK. PRECIP CHANCES
EARLY NEXT WEEK WILL FOCUS ON A COUPLE FEATURES. THE FIRST WILL BE
WITH THE STRONG WARM AIR ADVECTION THAT WILL TAKE PLACE LATE
SUNDAY NIGHT...WITH EVENING MODELS IN FAIRLY GOOD AGREEMENT IN
DEVELOPMENT OF SOME LIGHT SNOW ACROSS THE WESTERN CWA AFTER
MIDNIGHT...AND SPREADING OVER MUCH OF THE CWA ON MONDAY. SHOULD
SEE SOME TRANSITION OVER TO RAIN DURING THE DAY ACROSS THE SOUTH
HALF OF THE FORECAST AREA...AS TEMPERATURES RISE TO AROUND THE 40
DEGREE MARK. SECOND FOCUS WILL BE AS LOW PRESSURE DEVELOPS OVER
THE CENTRAL PLAINS AND TOWARD THE WESTERN OHIO VALLEY BY TUESDAY
MORNING...WITH AN INVERTED SURFACE TROUGH EXTENDING NORTHWEST
TOWARD THE UPPER LOW. HAVE MAINTAINED HEALTHY PRECIP CHANCES
THROUGH TUESDAY WITH THESE FEATURES...MOSTLY AS SNOW BUT WITH SOME
RAIN ACROSS THE SOUTHEAST. POTENTIAL EXISTS FOR ANOTHER 1 TO 3
INCHES OF SNOW EARLY NEXT WEEK.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
UPPER LOW SHOULD MAKE SOME STEADY PROGRESS SOUTHEAST AND FORM A
STRONG STORM SYSTEM OFF THE CAROLINA COAST BY MIDWEEK. THIS WILL
ALLOW FOR SOME UPPER RIDGING ACROSS THE CENTER OF THE NATION...
WITH MODERATING TEMPERATURES AS A SOUTHWEST UPPER FLOW SETS UP
LATER IN THE WEEK...AND HIGHS ARE LIKELY TO RETURN TO THE 50S BY
FRIDAY. ANY PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL NEXT
WEEKEND...BEYOND THE CURRENT FORECAST PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 556 AM CST SAT MAR 2 2013
PREDOMINANTLY VFR CONDITIONS EXPECTED ACROSS THE CENTRAL ILLINOIS
TERMINALS THROUGH THE 12Z TAF VALID TIME. THE PERSISTENT AREA OF
LOW CLOUDINESS...AS WELL AS A FEW FLURRIES...WILL GRADUALLY MOVE
OUT OF THE AREA TODAY AS HIGH PRESSURE STARTS TO BUILD ACROSS THE
TERMINALS. NORTHERLY WINDS TO THE EAST OF THE RIDGE AXIS SHOULD
TREND LIGHT/VARIABLE TONIGHT WITH THE APPROACH OF THE RIDGE.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
240 AM CST SAT MAR 2 2013
.DISCUSSION...
ISSUED 240 AM CST SAT MAR 2 2013
PESKY LONG-LASTING LIGHT SNOW IS FINALLY BEGINNING TO EXIT THE
AREA...AND WAS MAINLY SOUTH OF I-70 EARLY THIS MORNING. LOW CLOUD
DECK HAS BEEN ERODING FROM THE NORTH AND SOME BREAKS HAVE
DEVELOPED AS FAR SOUTH AS PEORIA...BUT STILL PLENTY OF CLOUDINESS
OVER THE AREA.
MAIN FORECAST CONCERNS INVOLVE PRECIPITATION CHANCES EARLY NEXT
WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
MOSTLY DRY CONDITIONS EXPECTED TODAY FOR A CHANGE. WILL NEED TO
MONITOR FOR SOME LINGERING LIGHT SNOW SHOWERS ACROSS THE EASTERN
CWA TODAY...ESPECIALLY WITH THE WIND TRAJECTORY COMING OFF LAKE
MICHIGAN. CLOUDS MAY BE A BIT SLOWER TO ERODE...WITH 925-850 MB
HUMIDITY PLOT OFF THE RAP MODEL KEEPING A FAIR AMOUNT OF
CLOUDINESS EAST OF I-55 WELL INTO THE AFTERNOON. HOWEVER...
CLEARING LATER TODAY AND TONIGHT WILL PRECEDE A RIDGE OF HIGH
PRESSURE THAT WILL CROSS THE STATE ON SUNDAY.
DEEP UPPER TROUGHING OVER THE EASTERN U.S. TO PUSH EASTWARD ON
SUNDAY...AS A SHORTWAVE IN SOUTHWEST CANADA BEGINS TO CLOSE OFF
AND DROP INTO THE NORTHERN PLAINS EARLY NEXT WEEK. PRECIP CHANCES
EARLY NEXT WEEK WILL FOCUS ON A COUPLE FEATURES. THE FIRST WILL BE
WITH THE STRONG WARM AIR ADVECTION THAT WILL TAKE PLACE LATE
SUNDAY NIGHT...WITH EVENING MODELS IN FAIRLY GOOD AGREEMENT IN
DEVELOPMENT OF SOME LIGHT SNOW ACROSS THE WESTERN CWA AFTER
MIDNIGHT...AND SPREADING OVER MUCH OF THE CWA ON MONDAY. SHOULD
SEE SOME TRANSITION OVER TO RAIN DURING THE DAY ACROSS THE SOUTH
HALF OF THE FORECAST AREA...AS TEMPERATURES RISE TO AROUND THE 40
DEGREE MARK. SECOND FOCUS WILL BE AS LOW PRESSURE DEVELOPS OVER
THE CENTRAL PLAINS AND TOWARD THE WESTERN OHIO VALLEY BY TUESDAY
MORNING...WITH AN INVERTED SURFACE TROUGH EXTENDING NORTHWEST
TOWARD THE UPPER LOW. HAVE MAINTAINED HEALTHY PRECIP CHANCES
THROUGH TUESDAY WITH THESE FEATURES...MOSTLY AS SNOW BUT WITH SOME
RAIN ACROSS THE SOUTHEAST. POTENTIAL EXISTS FOR ANOTHER 1 TO 3
INCHES OF SNOW EARLY NEXT WEEK.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
UPPER LOW SHOULD MAKE SOME STEADY PROGRESS SOUTHEAST AND FORM A
STRONG STORM SYSTEM OFF THE CAROLINA COAST BY MIDWEEK. THIS WILL
ALLOW FOR SOME UPPER RIDGING ACROSS THE CENTER OF THE NATION...
WITH MODERATING TEMPERATURES AS A SOUTHWEST UPPER FLOW SETS UP
LATER IN THE WEEK...AND HIGHS ARE LIKELY TO RETURN TO THE 50S BY
FRIDAY. ANY PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL NEXT
WEEKEND...BEYOND THE CURRENT FORECAST PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 1152 PM CST FRI MAR 1 2013...FOR THE 06Z TAFS
MVFR CONDITIONS WILL LIKELY LINGER THROUGH MUCH OF THE MORNING AT
THE TERMINAL SITES. THE NORTHERN TERMINALS WILL HAVE THE BETTER
CHANCES OF SEEING CLEARING ARRIVE FIRST...POSSIBLY IN THE MID TO
LATE MORNING. THE DRY NORTHERLY WINDS AT THE SURFACE AND ALOFT
WILL WORK TO ERODE THE CLOUD LAYER FROM N TO S. LITTLE TO NO SNOW
ACCUMULATION IS EXPECTED...BUT E-W RUNWAYS MAY SEE SOME LIGHT SNOW
ACCUMULATION AGAINST THE GRASS AS NORTH WINDS BLOW ANY LOOSE SNOW
ACROSS TRAVEL SURFACES...POSSIBLY MAKING THEM SLIPPERY.
WIND DIRECTIONS WILL REMAIN NORTH UNTIL LATER ON SATURDAY OR SAT
EVE WHEN WINDS BECOME MORE NW. WIND SPEEDS WILL DIP BELOW 10KT SAT
EVE DUE TO ADVANCING HIGH PRESSURE AND WEAKENING PRESSURE GRADIENT.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1119 AM CST SAT MAR 2 2013
.AVIATION...
VFR CONDITIONS THROUGH 03/18Z. HIGH PRESSURE WILL MOVE OVERHEAD
TONIGHT KEEPING SKIES CLEAR TO MOSTLY CLEAR WITH LIGHT WINDS INTO
MID MORNING ON SUNDAY. A DEVELOPING STORM SYSTEM IN THE NORTHERN
PLAINS WILL MOVE SOUTHEAST ON SUNDAY SPREADING INCREASING HIGH
CLOUDS ACROSS ALL THE TERMINALS TOWARD SUNRISE AND ESPECIALLY
SUNDAY MORNING. WINDS WILL SHIFT TO THE SOUTHEAST AT LESS THAN 10
KTS AFTER SUNRISE. CEILINGS WILL CONTINUE TO LOWER AFTER 18Z
SUNDAY AS THE STORM SYSTEM APPROACHES.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 324 AM CST SAT MAR 2 2013/
SYNOPSIS...
LATEST IR SATELLITE IMAGERY INDICATED THE NORTH TO SOUTH CLEARING
TREND OF LOW CLOUDS HAD COME TO A HALT ROUGHLY ALONG THE I-80
CORRIDOR OVER THE PAST FEW HOURS. SURFACE ANALYSIS INDICATED A LEE
TROUGH ACROSS THE WESTERN HIGH PLAINS FLANKED BY HIGH PRESSURE
REACHING FROM THE EASTERN DAKOTAS TO KS. OVER THE LOCAL AREA...A
LIGHT N-NE 925 MB AND 850 MB FLOW CONTINUED TO FEED MOISTURE FROM
THE GREAT LAKES...AND DEPARTING STORM SYSTEM INTO ESPECIALLY THE IL
SIDE OF THE FORECAST AREA. THIS TRAJECTORY SHOULD FINALLY BREAK DOWN
TODAY AS THE WESTERN U.S. UPPER RIDGE BUILDS AND EDGES EASTWARD...
PUSHING THE SURFACE RIDGE...AND A WEAK MID LEVEL ANTICYCLONE OVER
SOUTHERN LAKE MI EASTWARD.
SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGES ARE CENTERED ON CLOUD AND TEMPERATURE TRENDS. SHORT
TERM MODELS GENERALLY DEPICT THE MOISTURE LAYER AROUND 925 MB
ASSOCIATED WITH THE STRATUS DECK...THAT WAS COVERING MUCH OF WESTERN
AND SOUTHERN IA...SHIFTING SOUTHWARD TODAY. EAST OF THE MS
RIVER...THE EXTENSIVE STRATUS DECK IS SHOWN MAKING A WESTWARD
RESURGENCE IN THE AFTERNOON AFTER CLEARING THIS MORNING. THIS IS
MOST PRONOUNCED IN THE LATEST RAP RH FIELDS. FOR NOW...WILL KEEP A
MORE OPTIMISTIC FORECAST OF MOSTLY SUNNY SKIES OVER THE ENTIRE AREA
BY AFTERNOON...COUNTING ON THE EFFECTS OF INCREASING MID LEVEL
SUBSIDENCE WITH THE INCOMING UPPER LEVEL RIDGE. EVEN WITH
SUNSHINE...LOOKING AT HIGHS FROM UPSTREAM YESTERDAY AND CONSIDERING
925 MB TEMPERATURES THAT WILL BE SIMILAR TO YESTERDAY...HIGHS FROM
THE UPPER 20S NORTH TO LOWER 30S LOOK REASONABLE.
TONIGHT...THE SURFACE RIDGE TO THE WEST WEAKENS AS IT PASSES THROUGH
THE AREA ALLOWING WINDS TO BECOME LIGHT AND VARIABLE TOWARD MORNING.
SKIES SHOULD INITIALLY BE MOSTLY CLEAR...BUT THERE WILL BE A THREAT
OF INCREASING HIGH CLOUDS IN THE NW FLOW ALOFT. THIS WOULD PREVENT
TEMPERATURES FROM BOTTOMING OUT OVER OUR EXTENSIVE SNOWFIELD AND
FOR NOW WILL COUNT ON THIS OCCURRING TO HOLD MINS NO LOWER THAN
AROUND 10 NORTH TO THE MID TEENS SOUTH. IF HIGH CLOUDS DO NOT
MATERIALIZE...WIDESPREAD SINGLE DIGITS WOULD BE LIKELY...SIMILAR
TO WHAT IS OCCURRING THIS MORNING.
SHEETS
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY NIGHT THROUGH TUESDAY...THE NEXT SYSTEM TO AFFECT THE UPPER
MISSISSIPPI VALLEY WILL OCCUR SUNDAY NIGHT THROUGH TUESDAY. MODEL
FORECASTS ARE INCONSISTENT WITH LARGE DIFFERENCES NOTED IN THE
PLACEMENT OF THE UPPER LOW. 06Z SATURDAY WATER VAPOR SATELLITE
IMAGERY SHOWS THE SYSTEM IS CURRENTLY OVER THE GULF OF ALASKA. MODEL
SOLUTIONS WILL LIKELY CONTINUE TO BE INCONSISTENT UNTIL THE WAVE
MOVES ONSHORE AND GETS BETTER SAMPLED BY THE UPPER AIR NETWORK. AT
12Z MONDAY ALL MODELS SHOW THE UPPER LOW OVER MONTANA BUT LARGE
DIFFERENCE IN PLACEMENT OCCUR AFTER THAT. BY 18Z TUESDAY THE NAM
MOVES THE UPPER LOW FROM MONTANA TO SOUTHERN MINNESOTA...THE
ECMWF/DGEX MOVE THE UPPER LOW ACROSS IOWA/ILLINOIS WHILE THE GFS
TAKES THE LOW SOUTH OF THE REGION ACROSS MISSOURI. EVEN WITH THE
UPPER LOW PLACEMENT PROBLEMS...ALL MODELS SHOW AN ELEVATED WARM
ADVECTION WING AHEAD OF THE SYSTEM WHICH WOULD BREAK OUT SNOW ACROSS
THE AREA BEFORE DAYBREAK MONDAY MORNING. FOR NOW I HAVE HAVE KEPT
CURRENT FORECAST CHANCE POPS FOR SUNDAY NIGHT BUT RAISED POPS TO
LIKELY CATEGORY FOR MONDAY MORNING. SNOW WILL CONTINUE INTO TUESDAY
AS UPPER FORCING INCREASES AS THE UPPER LOW MOVES CROSSES OVER OR
NEAR THE REGION.
BOTTOM LINE...CONFIDENCE IS HIGH SNOW WILL FALL IN OR NEAR OUR
FORECAST AREA MONDAY AND TUESDAY. CONFIDENCE IS LOW AS TO SPECIFIC
LOCATION AND TOTAL SNOW AMOUNTS.
WEDNESDAY THROUGH FRIDAY...LATER IN THE WEEK THE UPPER AIR PATTERN
SHIFTS TO A SOUTHWESTERLY FLOW AS AN UPPER LEVEL RIDGE LOCATED OVER
THE ROCKIES BEGINS TO MOVE EAST. SURFACE WINDS WILL BE SOUTHERLY
COMING AROUND THE WEST SIDE OF HIGH PRESSURE LOCATED OVER THE GREAT
LAKES/OHIO VALLEY. TEMPERATURES SHOULD BE CLOSE TO NORMAL THURSDAY
AND COULD EVEN BE ABOVE NORMAL BY FRIDAY. THE END OF NEXT WEEK LOOKS
TO BE DRY.
KUHL
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
523 AM CST SAT MAR 2 2013
.AVIATION...
A RIDGE OF HIGH PRESSURE WILL MIGRATE EAST OUT OF THE PLAINS...
PROVIDING VFR CONDITIONS TODAY AND TONIGHT. THERE IS A LOW
POTENTIAL FOR PATCHY FOG TOWARD SUNDAY MORNING...BUT CONFIDENCE IS
TOO LOW TO INCLUDE IN THE FORECASTS. LIGHT NORTH TO NORTHWEST
WINDS WILL INCREASE TO NEAR 10 KNOTS TODAY...THEN BECOME LIGHT AND
VARIABLE OVERNIGHT.
SHEETS
&&
.PREV DISCUSSION... /ISSUED 324 AM CST SAT MAR 2 2013/
SYNOPSIS...
LATEST IR SATELLITE IMAGERY INDICATED THE NORTH TO SOUTH CLEARING
TREND OF LOW CLOUDS HAD COME TO A HALT ROUGHLY ALONG THE I-80
CORRIDOR OVER THE PAST FEW HOURS. SURFACE ANALYSIS INDICATED A LEE
TROUGH ACROSS THE WESTERN HIGH PLAINS FLANKED BY HIGH PRESSURE
REACHING FROM THE EASTERN DAKOTAS TO KS. OVER THE LOCAL AREA...A
LIGHT N-NE 925 MB AND 850 MB FLOW CONTINUED TO FEED MOISTURE FROM
THE GREAT LAKES...AND DEPARTING STORM SYSTEM INTO ESPECIALLY THE IL
SIDE OF THE FORECAST AREA. THIS TRAJECTORY SHOULD FINALLY BREAK DOWN
TODAY AS THE WESTERN U.S. UPPER RIDGE BUILDS AND EDGES EASTWARD...
PUSHING THE SURFACE RIDGE...AND A WEAK MID LEVEL ANTICYCLONE OVER
SOUTHERN LAKE MI EASTWARD.
SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGES ARE CENTERED ON CLOUD AND TEMPERATURE TRENDS. SHORT
TERM MODELS GENERALLY DEPICT THE MOISTURE LAYER AROUND 925 MB
ASSOCIATED WITH THE STRATUS DECK...THAT WAS COVERING MUCH OF WESTERN
AND SOUTHERN IA...SHIFTING SOUTHWARD TODAY. EAST OF THE MS
RIVER...THE EXTENSIVE STRATUS DECK IS SHOWN MAKING A WESTWARD
RESURGENCE IN THE AFTERNOON AFTER CLEARING THIS MORNING. THIS IS
MOST PRONOUNCED IN THE LATEST RAP RH FIELDS. FOR NOW...WILL KEEP A
MORE OPTIMISTIC FORECAST OF MOSTLY SUNNY SKIES OVER THE ENTIRE AREA
BY AFTERNOON...COUNTING ON THE EFFECTS OF INCREASING MID LEVEL
SUBSIDENCE WITH THE INCOMING UPPER LEVEL RIDGE. EVEN WITH
SUNSHINE...LOOKING AT HIGHS FROM UPSTREAM YESTERDAY AND CONSIDERING
925 MB TEMPERATURES THAT WILL BE SIMILAR TO YESTERDAY...HIGHS FROM
THE UPPER 20S NORTH TO LOWER 30S LOOK REASONABLE.
TONIGHT...THE SURFACE RIDGE TO THE WEST WEAKENS AS IT PASSES THROUGH
THE AREA ALLOWING WINDS TO BECOME LIGHT AND VARIABLE TOWARD MORNING.
SKIES SHOULD INITIALLY BE MOSTLY CLEAR...BUT THERE WILL BE A THREAT
OF INCREASING HIGH CLOUDS IN THE NW FLOW ALOFT. THIS WOULD PREVENT
TEMPERATURES FROM BOTTOMING OUT OVER OUR EXTENSIVE SNOWFIELD AND
FOR NOW WILL COUNT ON THIS OCCURRING TO HOLD MINS NO LOWER THAN
AROUND 10 NORTH TO THE MID TEENS SOUTH. IF HIGH CLOUDS DO NOT
MATERIALIZE...WIDESPREAD SINGLE DIGITS WOULD BE LIKELY...SIMILAR
TO WHAT IS OCCURRING THIS MORNING.
SHEETS
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY NIGHT THROUGH TUESDAY...THE NEXT SYSTEM TO AFFECT THE UPPER
MISSISSIPPI VALLEY WILL OCCUR SUNDAY NIGHT THROUGH TUESDAY. MODEL
FORECASTS ARE INCONSISTENT WITH LARGE DIFFERENCES NOTED IN THE
PLACEMENT OF THE UPPER LOW. 06Z SATURDAY WATER VAPOR SATELLITE
IMAGERY SHOWS THE SYSTEM IS CURRENTLY OVER THE GULF OF ALASKA. MODEL
SOLUTIONS WILL LIKELY CONTINUE TO BE INCONSISTENT UNTIL THE WAVE
MOVES ONSHORE AND GETS BETTER SAMPLED BY THE UPPER AIR NETWORK. AT
12Z MONDAY ALL MODELS SHOW THE UPPER LOW OVER MONTANA BUT LARGE
DIFFERENCE IN PLACEMENT OCCUR AFTER THAT. BY 18Z TUESDAY THE NAM
MOVES THE UPPER LOW FROM MONTANA TO SOUTHERN MINNESOTA...THE
ECMWF/DGEX MOVE THE UPPER LOW ACROSS IOWA/ILLINOIS WHILE THE GFS
TAKES THE LOW SOUTH OF THE REGION ACROSS MISSOURI. EVEN WITH THE
UPPER LOW PLACEMENT PROBLEMS...ALL MODELS SHOW AN ELEVATED WARM
ADVECTION WING AHEAD OF THE SYSTEM WHICH WOULD BREAK OUT SNOW ACROSS
THE AREA BEFORE DAYBREAK MONDAY MORNING. FOR NOW I HAVE HAVE KEPT
CURRENT FORECAST CHANCE POPS FOR SUNDAY NIGHT BUT RAISED POPS TO
LIKELY CATEGORY FOR MONDAY MORNING. SNOW WILL CONTINUE INTO TUESDAY
AS UPPER FORCING INCREASES AS THE UPPER LOW MOVES CROSSES OVER OR
NEAR THE REGION.
BOTTOM LINE...CONFIDENCE IS HIGH SNOW WILL FALL IN OR NEAR OUR
FORECAST AREA MONDAY AND TUESDAY. CONFIDENCE IS LOW AS TO SPECIFIC
LOCATION AND TOTAL SNOW AMOUNTS.
WEDNESDAY THROUGH FRIDAY...LATER IN THE WEEK THE UPPER AIR PATTERN
SHIFTS TO A SOUTHWESTERLY FLOW AS AN UPPER LEVEL RIDGE LOCATED OVER
THE ROCKIES BEGINS TO MOVE EAST. SURFACE WINDS WILL BE SOUTHERLY
COMING AROUND THE WEST SIDE OF HIGH PRESSURE LOCATED OVER THE GREAT
LAKES/OHIO VALLEY. TEMPERATURES SHOULD BE CLOSE TO NORMAL THURSDAY
AND COULD EVEN BE ABOVE NORMAL BY FRIDAY. THE END OF NEXT WEEK LOOKS
TO BE DRY. ..KUHL..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
324 AM CST SAT MAR 2 2013
.SYNOPSIS...
LATEST IR SATELLITE IMAGERY INDICATED THE NORTH TO SOUTH CLEARING
TREND OF LOW CLOUDS HAD COME TO A HALT ROUGHLY ALONG THE I-80
CORRIDOR OVER THE PAST FEW HOURS. SURFACE ANALYSIS INDICATED A LEE
TROUGH ACROSS THE WESTERN HIGH PLAINS FLANKED BY HIGH PRESSURE
REACHING FROM THE EASTERN DAKOTAS TO KS. OVER THE LOCAL AREA...A
LIGHT N-NE 925 MB AND 850 MB FLOW CONTINUED TO FEED MOISTURE FROM
THE GREAT LAKES...AND DEPARTING STORM SYSTEM INTO ESPECIALLY THE IL
SIDE OF THE FORECAST AREA. THIS TRAJECTORY SHOULD FINALLY BREAK DOWN
TODAY AS THE WESTERN U.S. UPPER RIDGE BUILDS AND EDGES EASTWARD...
PUSHING THE SURFACE RIDGE...AND A WEAK MID LEVEL ANTICYCLONE OVER
SOUTHERN LAKE MI EASTWARD.
&&
.SHORT TERM...TODAY AND TONIGHT...
MAIN CHALLENGES ARE CENTERED ON CLOUD AND TEMPERATURE TRENDS. SHORT
TERM MODELS GENERALLY DEPICT THE MOISTURE LAYER AROUND 925 MB
ASSOCIATED WITH THE STRATUS DECK...THAT WAS COVERING MUCH OF WESTERN
AND SOUTHERN IA...SHIFTING SOUTHWARD TODAY. EAST OF THE MS
RIVER...THE EXTENSIVE STRATUS DECK IS SHOWN MAKING A WESTWARD
RESURGENCE IN THE AFTERNOON AFTER CLEARING THIS MORNING. THIS IS
MOST PRONOUNCED IN THE LATEST RAP RH FIELDS. FOR NOW...WILL KEEP A
MORE OPTIMISTIC FORECAST OF MOSTLY SUNNY SKIES OVER THE ENTIRE AREA
BY AFTERNOON...COUNTING ON THE EFFECTS OF INCREASING MID LEVEL
SUBSIDENCE WITH THE INCOMING UPPER LEVEL RIDGE. EVEN WITH
SUNSHINE...LOOKING AT HIGHS FROM UPSTREAM YESTERDAY AND CONSIDERING
925 MB TEMPERATURES THAT WILL BE SIMILAR TO YESTERDAY...HIGHS FROM
THE UPPER 20S NORTH TO LOWER 30S LOOK REASONABLE.
TONIGHT...THE SURFACE RIDGE TO THE WEST WEAKENS AS IT PASSES THROUGH
THE AREA ALLOWING WINDS TO BECOME LIGHT AND VARIABLE TOWARD MORNING.
SKIES SHOULD INITIALLY BE MOSTLY CLEAR...BUT THERE WILL BE A THREAT
OF INCREASING HIGH CLOUDS IN THE NW FLOW ALOFT. THIS WOULD PREVENT
TEMPERATURES FROM BOTTOMING OUT OVER OUR EXTENSIVE SNOWFIELD AND
FOR NOW WILL COUNT ON THIS OCCURRING TO HOLD MINS NO LOWER THAN
AROUND 10 NORTH TO THE MID TEENS SOUTH. IF HIGH CLOUDS DO NOT
MATERIALIZE...WIDESPREAD SINGLE DIGITS WOULD BE LIKELY...SIMILAR
TO WHAT IS OCCURRING THIS MORNING.
SHEETS
.LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY NIGHT THROUGH TUESDAY...THE NEXT SYSTEM TO AFFECT THE UPPER
MISSISSIPPI VALLEY WILL OCCUR SUNDAY NIGHT THROUGH TUESDAY. MODEL
FORECASTS ARE INCONSISTENT WITH LARGE DIFFERENCES NOTED IN THE
PLACEMENT OF THE UPPER LOW. 06Z SATURDAY WATER VAPOR SATELLITE
IMAGERY SHOWS THE SYSTEM IS CURRENTLY OVER THE GULF OF ALASKA. MODEL
SOLUTIONS WILL LIKELY CONTINUE TO BE INCONSISTENT UNTIL THE WAVE
MOVES ONSHORE AND GETS BETTER SAMPLED BY THE UPPER AIR NETWORK. AT
12Z MONDAY ALL MODELS SHOW THE UPPER LOW OVER MONTANA BUT LARGE
DIFFERENCE IN PLACEMENT OCCUR AFTER THAT. BY 18Z TUESDAY THE NAM
MOVES THE UPPER LOW FROM MONTANA TO SOUTHERN MINNESOTA...THE
ECMWF/DGEX MOVE THE UPPER LOW ACROSS IOWA/ILLINOIS WHILE THE GFS
TAKES THE LOW SOUTH OF THE REGION ACROSS MISSOURI. EVEN WITH THE
UPPER LOW PLACEMENT PROBLEMS...ALL MODELS SHOW AN ELEVATED WARM
ADVECTION WING AHEAD OF THE SYSTEM WHICH WOULD BREAK OUT SNOW ACROSS
THE AREA BEFORE DAYBREAK MONDAY MORNING. FOR NOW I HAVE HAVE KEPT
CURRENT FORECAST CHANCE POPS FOR SUNDAY NIGHT BUT RAISED POPS TO
LIKELY CATEGORY FOR MONDAY MORNING. SNOW WILL CONTINUE INTO TUESDAY
AS UPPER FORCING INCREASES AS THE UPPER LOW MOVES CROSSES OVER OR
NEAR THE REGION.
BOTTOM LINE...CONFIDENCE IS HIGH SNOW WILL FALL IN OR NEAR OUR
FORECAST AREA MONDAY AND TUESDAY. CONFIDENCE IS LOW AS TO SPECIFIC
LOCATION AND TOTAL SNOW AMOUNTS.
WEDNESDAY THROUGH FRIDAY...LATER IN THE WEEK THE UPPER AIR PATTERN
SHIFTS TO A SOUTHWESTERLY FLOW AS AN UPPER LEVEL RIDGE LOCATED OVER
THE ROCKIES BEGINS TO MOVE EAST. SURFACE WINDS WILL BE SOUTHERLY
COMING AROUND THE WEST SIDE OF HIGH PRESSURE LOCATED OVER THE GREAT
LAKES/OHIO VALLEY. TEMPERATURES SHOULD BE CLOSE TO NORMAL THURSDAY
AND COULD EVEN BE ABOVE NORMAL BY FRIDAY. THE END OF NEXT WEEK LOOKS
TO BE DRY. ..KUHL..
&&
.AVIATION...
VFR CONDITIONS EXPECTED TO PERSIST FOR AT LEAST THE NEXT 24 HOURS.
STRATUS WITH VFR CIGS ACROSS SE IA AND NW IL IS EXPECTED TO
GRADUALLY DECREASE THIS MORNING AS HIGH PRESSURE AND LOW LEVEL DRY
AIR CONTINUES BUILDING IN. FEW TO SCATTERED CUMULUS WITH BASES OF
2500-3500 FT AGL MAY ALSO DEVELOP BY LATE MORNING THROUGH MID
AFTERNOON. NORTHERLY WINDS WILL CONTINUE GENERALLY AT 4-11 KTS
THROUGH AFTERNOON...THEN BECOME NEAR CALM BY EVENING AS HIGH
PRESSURE SETTLES OVERHEAD.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHEETS/KUHL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1037 AM MST SAT MAR 2 2013
.UPDATE...
ISSUED AT 941 AM MST SAT MAR 2 2013
JUST COMPLETED AN UPDATE. FIRST INCREASED CLOUD COVER THROUGH THE
DAY. THIS ADJUSTED TONIGHTS AND SUNDAYS CLOUD COVER PER LATEST
GUIDANCE AND TRENDS. DESPITE THE CLOUD COVER...TEMPERATURES ARE
RAPIDLY RISING ESPECIALLY IN THE WEST. MIXING APPEARS TO BE BETTER
THAN MOST MODEL OUTPUT SINCE THE MODELS PERCEIVED SNOW COVER IS
OVER AFFECTING ITS FORECAST. HRRR CONFIRMED BY LATEST 850 MB
TEMPERATURE GUIDANCE IS CATCHING THIS VERY WELL AND USED THEM FOR
THE UPDATE. WILL PROBABLY HAVE TO RAISE TOMORROWS MAXES PER TODAYS
TRENDS AND GUIDANCE. ALSO USED THE HRRR WINDS FOR THE REST OF THE
DAY AS WELL.
&&
.SHORT TERM...(TODAY AND MONDAY NIGHT)
ISSUED AT 247 AM MST SAT MAR 2 2013
SHORT TERM FORECAST CONCERNS ARE THE WARM TEMPERATURES THROUGH THE
WEEKEND FOLLOWED BY COOLER TEMPERATURES AND WINDY CONDITIONS ON
MONDAY.
MODELS ARE IN REASONABLE AGREEMENT...BUT BEGIN TO DIVERGE BY
MONDAY NIGHT AS THE APPROACHING UPPER LOW CENTER MOVES EAST OF THE
ROCKIES.
THE LARGE UPPER RIDGE CURRENTLY OVER THE WESTERN UNITED STATES
WILL MOVE EAST OVER THE ROCKIES AND HIGH PLAINS TODAY AND TONIGHT
AS IT BEGINS TO FLATTEN WITH THE APPROACH OF A LOW CENTER OVER THE
PACIFIC NORTHWEST. THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS
CONTINUES TO FLATTEN THROUGH SUNDAY AND SUNDAY NIGHT AS THE UPPER
LOW MOVES INTO THE NORTHERN HIGH PLAINS BY EARLY MONDAY MORNING.
SURFACE FLOW ACROSS THE FORECAST AREA THROUGH EARLY SUNDAY WILL
BE OUT OF THE SOUTHWEST TO WEST AHEAD OF THE DEEPENING SURFACE LEE
TROUGH WITH WARMER TEMPERATURES GENERALLY OVER THE WEST AND
COOLER TEMPERATURES IN THE EASTERN SECTIONS WHERE THE SNOW COVER
WILL STILL AFFECT DAYTIME TEMPERATURES. A COLD FRONT PUSHES INTO
THE REGION EARLY MONDAY MORNING AHEAD OF THE UPPER LOW...WITH GUSTY
NORTHWEST WINDS EXPECTED THROUGH THE DAY ON MONDAY BEHIND THE
FRONT. HAVE KEPT WIND SPEEDS BELOW ADVISORY CRITERIA FOR NOW AS
WIND SPEED VALUES ARE FLIP-FLOPPING SOMEWHAT WITH EACH RUN. THE UPPER
LOW MOVES INTO THE CENTRAL PLAINS STATES OVERNIGHT MONDAY NIGHT.
MODELS ARE HINTING AT POSSIBLE PRECIPITATION MONDAY INTO MONDAY
NIGHT...BUT HAVE SO FAR KEPT DRY CONDITIONS IN THE FORECAST AND
NUDGED THE POPS SLIGHTLY HIGHER DURING THAT PERIOD.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 247 AM MST SAT MAR 2 2013
TUESDAY-SATURDAY...H5 RIDGE BUILDS BACK OVER CWA WITH DRY CONDITIONS
AND WARMING TREND THROUGH THE PERIODS. TUESDAY SHOULD BE BELOW
NORMAL WITH NORTHERLY FLOW STILL IN PLACE AND COOL AIR MASS
LINGERING. CURRENTLY EXPECTING HIGHS IN THE UPPER 30S TO MID 40S FROM
EAST TO WEST. WARMING TREND KICKS IN ON WED WHEN HIGHS COULD BE
NEAR 60F ACROSS WESTERN LOCATIONS. HIGHS ON THU SHOULD BE IN THE 60S
ACROSS MOST OF THE CWA. LARGE SCALE TROUGH WITH CLOSED CENTER IS
PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION. A COLD FRONT IS
EXPECTED TO DROP SOUTH OVER THE CWA FRI OR FRI NIGHT WHICH SHOULD
BRING TEMPS BACK TO SEASONAL VALUES NEAR 50F. TROUGH WILL STILL BE
WELL WEST OF CWA...HOWEVER GUIDANCE IS SHOWING DECENT FORCING AND
MOISTURE SPREADING OUT AHEAD OF THE MAIN TROUGH...WITH
SHOWERS/THUNDERSTORMS POSSIBLE OVER CENTRAL KS AHEAD OF COLD FRONT.
CURRENT GUIDANCE KEEPS BETTER CHANCES SOUTH AND EAST DURING THE DAY
FRI...SO I KEPT FORECAST DRY FOR NOW.
GUIDANCE SHOWS BETTER PRECIP CHANCES FRI NIGHT THROUGH SAT NIGHT
WHICH IS OUTSIDE THE VALID FORECAST PERIOD. THE CLOSED LOW OVER THE
FOUR CORNERS REGION IS PROGGED TO MOVE INTO THE PLAINS...WITH QUITE
A BIT OF SPREAD BETWEEN MODELS ON HOW THIS SYSTEM EVOLVES...AND
WHERE IT TRACKS. BECAUSE OF THIS...CONFIDENCE IS LOW ON WHAT IMPACTS
WE CAN ANTICIPATE OVER OUR CWA. FOR NOW GUIDANCE WOULD AT LEAST
INDICATE A STRONG STORM SYSTEM IMPACTING THE SOUTHERN OR CENTRAL
PLAINS NEXT WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1037 AM MST SAT MAR 2 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...DR
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
947 AM MST SAT MAR 2 2013
.UPDATE...
ISSUED AT 941 AM MST SAT MAR 2 2013
JUST COMPLETED AN UPDATE. FIRST INCREASED CLOUD COVER THROUGH THE
DAY. THIS ADJUSTED TONIGHTS AND SUNDAYS CLOUD COVER PER LATEST
GUIDANCE AND TRENDS. DESPITE THE CLOUD COVER...TEMPERATURES ARE
RAPIDLY RISING ESPECIALLY IN THE WEST. MIXING APPEARS TO BE BETTER
THAN MOST MODEL OUTPUT SINCE THE MODELS PERCEIVED SNOW COVER IS
OVER AFFECTING ITS FORECAST. HRRR CONFIRMED BY LATEST 850 MB
TEMPERATURE GUIDANCE IS CATCHING THIS VERY WELL AND USED THEM FOR
THE UPDATE. WILL PROBABLY HAVE TO RAISE TOMORROWS MAXES PER TODAYS
TRENDS AND GUIDANCE. ALSO USED THE HRRR WINDS FOR THE REST OF THE
DAY AS WELL.
&&
.SHORT TERM...(TODAY AND MONDAY NIGHT)
ISSUED AT 247 AM MST SAT MAR 2 2013
SHORT TERM FORECAST CONCERNS ARE THE WARM TEMPERATURES THROUGH THE
WEEKEND FOLLOWED BY COOLER TEMPERATURES AND WINDY CONDITIONS ON
MONDAY.
MODELS ARE IN REASONABLE AGREEMENT...BUT BEGIN TO DIVERGE BY
MONDAY NIGHT AS THE APPROACHING UPPER LOW CENTER MOVES EAST OF THE
ROCKIES.
THE LARGE UPPER RIDGE CURRENTLY OVER THE WESTERN UNITED STATES
WILL MOVE EAST OVER THE ROCKIES AND HIGH PLAINS TODAY AND TONIGHT
AS IT BEGINS TO FLATTEN WITH THE APPROACH OF A LOW CENTER OVER THE
PACIFIC NORTHWEST. THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS
CONTINUES TO FLATTEN THROUGH SUNDAY AND SUNDAY NIGHT AS THE UPPER
LOW MOVES INTO THE NORTHERN HIGH PLAINS BY EARLY MONDAY MORNING.
SURFACE FLOW ACROSS THE FORECAST AREA THROUGH EARLY SUNDAY WILL
BE OUT OF THE SOUTHWEST TO WEST AHEAD OF THE DEEPENING SURFACE LEE
TROUGH WITH WARMER TEMPERATURES GENERALLY OVER THE WEST AND
COOLER TEMPERATURES IN THE EASTERN SECTIONS WHERE THE SNOW COVER
WILL STILL AFFECT DAYTIME TEMPERATURES. A COLD FRONT PUSHES INTO
THE REGION EARLY MONDAY MORNING AHEAD OF THE UPPER LOW...WITH GUSTY
NORTHWEST WINDS EXPECTED THROUGH THE DAY ON MONDAY BEHIND THE
FRONT. HAVE KEPT WIND SPEEDS BELOW ADVISORY CRITERIA FOR NOW AS
WIND SPEED VALUES ARE FLIP-FLOPPING SOMEWHAT WITH EACH RUN. THE UPPER
LOW MOVES INTO THE CENTRAL PLAINS STATES OVERNIGHT MONDAY NIGHT.
MODELS ARE HINTING AT POSSIBLE PRECIPITATION MONDAY INTO MONDAY
NIGHT...BUT HAVE SO FAR KEPT DRY CONDITIONS IN THE FORECAST AND
NUDGED THE POPS SLIGHTLY HIGHER DURING THAT PERIOD.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 247 AM MST SAT MAR 2 2013
TUESDAY-SATURDAY...H5 RIDGE BUILDS BACK OVER CWA WITH DRY CONDITIONS
AND WARMING TREND THROUGH THE PERIODS. TUESDAY SHOULD BE BELOW
NORMAL WITH NORTHERLY FLOW STILL IN PLACE AND COOL AIR MASS
LINGERING. CURRENTLY EXPECTING HIGHS IN THE UPPER 30S TO MID 40S FROM
EAST TO WEST. WARMING TREND KICKS IN ON WED WHEN HIGHS COULD BE
NEAR 60F ACROSS WESTERN LOCATIONS. HIGHS ON THU SHOULD BE IN THE 60S
ACROSS MOST OF THE CWA. LARGE SCALE TROUGH WITH CLOSED CENTER IS
PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION. A COLD FRONT IS
EXPECTED TO DROP SOUTH OVER THE CWA FRI OR FRI NIGHT WHICH SHOULD
BRING TEMPS BACK TO SEASONAL VALUES NEAR 50F. TROUGH WILL STILL BE
WELL WEST OF CWA...HOWEVER GUIDANCE IS SHOWING DECENT FORCING AND
MOISTURE SPREADING OUT AHEAD OF THE MAIN TROUGH...WITH
SHOWERS/THUNDERSTORMS POSSIBLE OVER CENTRAL KS AHEAD OF COLD FRONT.
CURRENT GUIDANCE KEEPS BETTER CHANCES SOUTH AND EAST DURING THE DAY
FRI...SO I KEPT FORECAST DRY FOR NOW.
GUIDANCE SHOWS BETTER PRECIP CHANCES FRI NIGHT THROUGH SAT NIGHT
WHICH IS OUTSIDE THE VALID FORECAST PERIOD. THE CLOSED LOW OVER THE
FOUR CORNERS REGION IS PROGGED TO MOVE INTO THE PLAINS...WITH QUITE
A BIT OF SPREAD BETWEEN MODELS ON HOW THIS SYSTEM EVOLVES...AND
WHERE IT TRACKS. BECAUSE OF THIS...CONFIDENCE IS LOW ON WHAT IMPACTS
WE CAN ANTICIPATE OVER OUR CWA. FOR NOW GUIDANCE WOULD AT LEAST
INDICATE A STRONG STORM SYSTEM IMPACTING THE SOUTHERN OR CENTRAL
PLAINS NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 441 AM MST SAT MAR 2 2013
VFR CONDITIONS WILL PREVAIL AT GLD WITH NORTHWEST WINDS
INCREASING SLIGHTLY DURING DAYLIGHT HOURS...BECOMING LIGHT
WESTERLY AFTER SUNSET.
MCK WILL START OUT MVFR WITH CALM WINDS AND LOWER VISIBILITIES
PRODUCED BY AREAS OF FOG. AREAS OF FOG WILL DISSIPATE BY LATE
MORNING AS WESTERLY WINDS BECOME LIGHT WITH CONDITIONS BECOMING
VFR. VFR CONDITIONS WILL CONTINUE THROUGH THE REMAINDER OF THE TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...DR
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
624 PM EST SUN MAR 3 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 350 PM EST SUN MAR 3 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHORTWAVE TROUGH
OVER NRN MONTANA...A MID/UPPER LEVEL RIDGE OVER THE PLAINS AND NE
CANADA AND TROUGHING OVER NRN MANTIOBA AND THE SE CONUS LEAVING A
COL OVER THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM NW
ONTARIO THROUGH WRN UPPER MI INTO WI AND IL. SIMILAR TO
YESTERDAY...LES AND CLOUDS HAVE DIMINISHED DURING THE AFTERNOON AS
DAYTIME MIXING AND VERY DRY AIS UPSTREAM HELPS ERODE THE
CLOUD BANDS.
TONIGHT AND MON...ALSO SIMILAR TO PREVIOUS FEW NIGHTS...EXPECT SOME LES
TO REDEVLOP OVERNIGHT AS UPSTREAM MIXING/DRYING SUBSIDES AND LAND
BREEZES DEVELOP. HOWEVER...HIGH RES MODELS SUGGEST THAT LOW LEVEL
CONV WILL BE WEAKER THAN LAST NIGHT WITH MAINLY DIFLUENT ACYC FLOW
OVER THE THE WEST HALF OF LAKE SUPERIOR. WEAK UPSLOPE FLOW INTO N
CNTRL UPPER MI SHOULD HELP PRODUCE AT LEAST SOME FLURRIES EVEN WITH
INVERSION HEIGHTS AT OR BELOW 2K-3K FT. WITH LOW CONFIDENCE IN EVEN
ANY LIGHT MEASURABLE LES...FCST RETAINED PREV MENTION OF SLIGHT
CHANCE POPS. FAVORABLE RADIATIONAL COOLING CONDITIONS INLAND SHOULD
WILL ALLOW TEMPS TO DROP TO LOWER END OF GUIDANCE WITH READINGS IN
THE 0 TO 10 BELOW ZERO RANGE.
AS ACYC WINDS BACK TO THE ENE...EXPECT REMAINING LES/FLURRIES TO END
BY MIDDAY MON. TEMPS SHOULD REBOUND TO READINGS CLOSER TO SEASONAL
AVERAGES NEAR 30...PER FCST SOUNDINGS LOW LEVEL TEMP PROFILE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EST SUN MAR 3 2013
FOCUS INITIALY IS ON SHORTWAVE TROUGH DIGGING SOUTHEAST ACROSS
NORTHERN PLAINS. CONVERGENCE AND MOISTURE ADVECTION ALONG AND
NORTH OF SFC/H85/H7 LOWS AND DIVERGENCE ALOFT FROM H25 JET STREAK
SHOULD BE SUPPORTING SWATH OF MODERATE TO HEAVY SNOW FROM EASTERN
NORTH DAKOTA THROUGH MOST OF MINNESOTA AND INTO SOUTHERN WISCONSIN.
H85-H7 FRONTOGENESIS AND H85 MOISTURE STAY FAR ENOUGH TO SOUTH TO
KEEP NORTHERN EDGE OF SNOW SHIELD OUT OF CWA MONDAY NIGHT. H7-H6
FRONTOGENESIS AND INCREASING 1000-700MB MOISTURE PROBABLY WILL ALLOW
SYSTEM SNOW TO CLIP FAR WEST TUESDAY. KIWD WOULD SEE BEST CHANCE OF
SEEING THIS SYSTEM SNOW. FARTHER NORTH...EXPECT INCREASING LIGHT
SNOW MAINLY DUE TO WINDS BECOMING MORE NORTHEAST AND WITH INCREASING
925-850MB MOISTURE. THE ADDITIONAL MOISTURE ALONG WITH FLOW OFF LK
SUPERIOR AND MINOR COOLING AT TOP OF INVERSION TO AROUND -12C WILL
BE SUFFICIENT TO RESULT IN LAKE ENHANCED SNOW. GIVEN THE PERSISTENT
LIGHT LK EFFECT SEEN OFF AND ON OVER NCNTRL UPR MICHIGAN SINCE
THURSDAY WITH QUITE MARGINAL CONDITIONS IN TERMS OF INVERSION
HEIGHT/TEMPS...PRETTY CONFIDENT SNOW WILL OCCUR TUESDAY/TUESDAY
NIGHT/WEDNESDAY MORNING. TOTAL SNOW ACCUMULATIONS WILL BE LIMITED
GIVEN ABSENCE OF LARGER SCALE FORCING AND WITH MAJORITY OF LIFT
OCCURRING AT TEMPS WARMER THAN -10C LEADING TO SLR/S LESS THAN 10:1.
EVEN SO...SOME HIGHER TERRAIN AREAS OVER FAR WESTERN UPR MICHIGAN
AND IN NCNTRL UPR MICHIGAN MAY END UP WITH A FEW INCHES OF SNOW BY
LATER WEDNESDAY.
H925 TEMPS AROUND -10C WITH WEAK NORTHERLY WINDS AND SUFFICIENT
MOISTURE BLO INVERSION WILL RESULT IN LIGHT LK EFFECT PERSISTING
THROUGH LATE WEDNESDAY. SINCE SFC-H925MB WINDS DO NOT BECOME MORE
SOUTHERLY UNTIL THURSDAY MORNING...LIGHT LK EFFECT/FLURRIES PROBABLY
WILL LINGER ALONG PORTIONS OF LK SUPERIOR SHORE WEDNESDAY NIGHT. BY
TIME WINDS DO BECOME MORE SOUTHERLY...TEMPS ARE FURTHER WARMING...SO
DO NOT EXPECT ANY LK EFFECT OFF LK MICHIGAN. COULD BE ENHANCEMENT TO
CLOUDS THOUGH WHICH WOULD TEMPER WARMING ON THURSDAY FOR THE EAST.
H5 RIDGE BUILDS FROM CNTRL CONUS ACROSS GREAT LAKES THURSDAY INTO
FRIDAY. BY LATER FRIDAY...TROUGH OVER WESTERN CONUS SPLITS LEAVING
SEPARATE SOUTHERN STREAM TROUGH OVER SOUTHWEST CONUS AND NORTHERN
STREAM TROUGH PUSHING ACROSS SCNTRL CANADA. SFC-H85 TROUGHING FORMS
IN RESPONSE OVER THE NORTEHRN PLAINS WHICH INCREASES SOUTHERLY
WINDS OVER UPR LAKES THURSDAY NIGHT INTO FRIDAY. WINDS MAY BECOME
BREEZY WITH GUSTS OVER 20 MPH...BUT LACK OF STRONGER PRESSURE
GRADIENT WILL KEEP REAL STRONG WINDS FROM OCCURRING.
GFS INDICATES STRONGER NORTHERN STREAM DYNAMICS HEAD EAST QUICKLY ON
FRIDAY WHILE OUTRUNNING THE SFC TROUGH...SO THE TROUGH REALLY LOSES
ITS PUNCH AS IT MOVES ACROSS THE AREA. ECMWF FAIRLY SIMILAR WITH
OVERALL IDEA. SHOULD NOTE THAT THE GEM-NH A BIT STRONGER/FARTHER
SOUTH WITH NORTHERN STREAM WAVE SO IT GENERATES MORE QPF IN WARM AIR
ADVECTION AHEAD OF THE WAVE ON FRIDAY. GFS TRYING TO GENERATE SOME
LGT DRIZZLE LIKE PRECIP ON FRIDAY WITH LOW-LEVEL MOISTURE BENEATH
DRIER AIR IN MID LEVELS. THINK THAT LACK OF DEEPER MOISTURE INTO THE
SYSTEM SUGGESTS THAT NOT MUCH PRECIPITATION WILL OCCUR ON FRIDAY.
WILL NOT ALTER SLIGHT CHANCE POPS FROM CONSENSUS OF MODELS. SOME
INDICATION THAT AS WARMING KICKS IN ABOVE H9 AHEAD OF THE
TROUGH...LOW-LEVEL MOISTURE MAY REMAIN TRAPPED BENEATH THE INVERSION
OVER MUCH OF CWA RIGHT THROUGH FRIDAY. MAIN IMPACT WILL BE ON TEMPS
THURSDAY THROUGH FRIDAY. DUE TO STRICT TEMPERATURE ADVECTION WOULD
THINK MANY AREAS THURSDAY AND FRIDAY WILL STILL BE ABLE TO CRACK THE
FREEZING MARK.
MODELS NOT AS COLD IN WAKE OF FRONT NEXT WEEKEND AS THEY HAVE SHOWED
LAST COUPLE DAYS. ULTIMATELY MAY END UP BEING DRY NEXT WEEKEND /JUST
HAVE SLIGHT CHANCES IN THERE/ WITH TEMPERATURES SIMILAR TO LATE THIS
WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 623 PM EST SUN MAR 3 2013
VFR CONDITIONS WILL PREAVIL THROUGH THE FCST PERIOD WITH A SURFACE
RIDGE DOMINATING THE WEATHER IN THE NORTHERN GREAT LAKES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EST SUN MAR 3 2013
STRONGEST WINDS THIS WEEK OCCUR MONDAY AFTERNOON THROUGH TUESDAY
OVER FAR WESTERN LAKE SUPERIOR AS LOW PRESSURE SYSTEM MOVES BY JUST
TO THE SOUTH. EAST-NORTHEAST WINDS TO 30 KTS GOOD BET. MAY BE GALE
GUSTS TOWARD THE HEAD OF LK SUPERIOR AND ALONG THE MINNESOTA SHORE
MONDAY NIGHT INTO TUESDAY MORNING DUE TO COASTAL CONVERGENCE. NORTH
WINDS TO 25 KTS CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY
WINDS AND COLDER TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT
TIMES THROUGH WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WEDNESDAY AND THURSDAY AS HIGH PRESSURE CROSSES THE REGION.
SOUTH WINDS TO 25 KTS POSSIBLE THURSDAY NIGHT INTO FRIDAY OUT AHEAD
OF LOW PRESSURE TROUGH. TROUGH MOVES THROUGH FRIDAY NIGHT BUT
WEST-NORTHWEST WINDS IN WAKE OF TROUGH SHOULD STAY BLO 20 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EST SAT MAR 2 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 400 PM EST SAT MAR 2 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE WRN CONUS AND
AND TROUGHING OVER THE EAST...RESULTING IN NW MID/UPPER LEVEL FLOW
FROM WRN CANADA THROUGH THE PLAINS INTO THE LOWER MS VALLEY. AT THE
SFC...A RIDGE EXTENDED FROM HUDSON BAY AN NW ONTARIO THROUGH WRN
LAKE SUPERIOR. DAYTIME MIXING AND LOW LEVEL DRYING UPSTREAM
(DEWPOINT DEPRESSIONS AOA 30F) HAS SUBSTANTIALLY REDUCED THE
COVERAGE/INTENSITY OF LES INTO N CNTRL UPPER MI THIS AFTERNOON.
TONIGHT...A WEAK SHORTWAVE TROUGH TO NEAR INL WILL DIVE SE
REINFORCING THE MID LEVEL TROUGH OVER THE NRN GREAT LAKES.
HOWEVER..THE SFC RIDGE EXTENDING SOUTH FROM THE HUDSON BAY HIGH WILL
CONTINUE TO BE THE DOMINANT FEATURE OVER THE AREA. INVERSION HEIGHTS
BETWEEN 2K TO 3K FT AND THE VERY DRY AIR UPSTREAM NORTH OF LAKE
SUPERIOR...WILL HELP SUPPRESS LAKE EFFECT SNOW CHANCES/INTENSITY
DESPITE TEMPS FCST NEAR -14C AT THE BASE OF THE INVERSION.
AS LAND BREEZES DEVELOP TONIGHT...INCREASING LOW LEVEL CONVERGENCE
SHOULD STRENGTHEN LES WITH SCT -SHSN INTO NORTH CENTRAL UPPER MI FROM
MARQUETTE TO MUNISING. ANY SNOWFALL AMOUNTS...HOWEVER SHOULD BE
LIGHT AMOUNTS OF A HALF INCH OR LESS. LAKE CLOUDS ARE EXPECTED TO
LIMIT TEMP FALL OVER CNTRL AND EAST PORTIONS OF THE CWA...BUT WITH
LIGHT/CALM WINDS AND SOME CLEARING INLAND WEST...TEMPS SHOULD DROP
INTO THE SINGLE DIGITS BLO ZERO...WITH SOME LOCALLY COLDER TEMPS
POSSIBLE.
SUNDAY...SIMILAR TO TODAY...EXPECT THAT LES IN THE MORNING MAINLY
INTO N CNTRL UPPER MI WILL DIMINISH IN THE AFTERNOON WITH THE SFC
RIDGE REMAINING OVER THE REGION. EXPECT MAX TEMPERATURES TO CLIMB
INTO THE MID AND UPPER 20S AS THE ARCTIC AIRMASS SLOWLY MODIFIES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 PM EST SAT MAR 2 2013
TROUGH THAT HAS BEEN STUCK OVER THE GREAT LAKES THROUGH MOST OF THIS
PAST WEEK LOOKS TO FINALLY EASE BY MID-LATE WEEK. A MORE SIGNIFICANT
SHORTWAVE TROUGH DIGS INTO THE MEAN TROUGH MONDAY THROUGH WEDNESDAY.
BASED ON TRACK OF SHORTWAVE AND H85-H5 Q-VECTOR CONVERGENCE...MOST
OF THE SNOW FROM THAT SYSTEM WILL IMPACT MOST OF MINNESOTA THROUGH
WISCONSIN AND INTO LOWER MICHIGAN. EVEN THOUGH SFC-H85 LOWS REMAIN
WELL TO SOUTH OF UPR MICHIGAN...NORTHEAST WINDS BTWN THE LOWS AND
HIGH PRESSURE OVER HUDSON BAY AND ENOUGH LOW-LEVEL MOISTURE THROUGH
H9 ALONG WITH COLD ENOUGH TEMPS AT TOP OF INVERSION SHOULD SUPPORT
LIGHT LK EFFECT THROUGH WEDNESDAY BEFORE WINDS BECOME LIGHT AND
VARIABLE. SIMILAR TO WHAT WE HAVE SEEN LATELY THE SNOW WILL BE
AROUND BUT NOT ACCUMULATE MUCH AS INVERSION HEIGHTS REMAINING
BLO 3KFT LIMIT LK EFFECT INTENSITY AND MARGINALLY COLD AIR LIMITS
FLUXES OFF THE LAKES. INCREASING MOISTURE THROWN TO NORTH OF EARLY
WEEK LOW PRESSURE SYSTEM MAY HELP ENHANCE THE SNOW SLIGHTLY MONDAY
NIGHT AND TUESDAY IN AREAS FAVORED BY NORTHEAST WINDS. PERHAPS SOME
LIGHT SNOW ACCUMULATIONS OF A FEW INCHES MAY OCCUR DURING THAT TIME.
TEMPERATURES THROUGH WEDNESDAY WILL BE GRADUALLY WARMING...BUT STILL
ONLY INTO LOWER 30S. TRICKY FORECAST NIGHTTIME LOWS SUNDAY NIGHT AS
AREAS AWAY FROM THE CLOUDS AND SNOW SHOWERS NEAR LK SUPERIOR MAY
EASILY DROP BLO ZERO. MORE CLOUDS ON MONDAY NIGHT AND TUESDAY NIGHT
SHOULD RESULT IN READINGS STAYING MOSTLY IN THE TEENS ABOVE ZERO.
HIGH PRESSURE MOVING INTO THE AREA WEDNESDAY NIGHT WILL BEGIN TO
TURN WINDS TO THE SOUTH AND WILL FINALLY END LIGHT LK EFFECT BY
THURSDAY. BY FRIDAY...UPPER LEVEL TROUGH DEVELOPS FROM WESTERN
CONUS THROUGH NORTHERN PLAINS WHILE RIDGING MOVES ACROSS GREAT LAKES
IN WAKE OF THE EARLY WEEK SYSTEM. EXPECT LOW PRESSURE TO FORM ON
LEADING EDGE OF TROUGH OVER THE PLAINS...THOUGH THE STORM SHOULD NOT
BE TOO STRONG AS LOW-LEVEL TEMPERATURE CONTRAST PRECEEDING THE
SYSTEM IS MINIMAL. GFS AND ECMWF THEN SHOW TROUGH SPLITTING BY
FRIDAY WITH SOUTHERN STREAM PORTION CLOSING OFF OVER SOUTHWEST
CONUS WHILE NORTHERN BRANCH SHORTWAVE MOVES EAST ACROSS SOUTH
CENTRAL CANADA. NORTHERN TROUGH MOVING EAST WILL DRAG THE WEAKER LOW
PRESSURE SYSTEM AND ASSOCIATED COLD FRONT ACROSS GREAT LAKES LATER
ON FRIDAY. GFS REMAINS QUICKER WITH THIS COLD FROPA COMPARED TO
ECMWF AND GEM-NH. COULD BE SOME PRECIPITATION WITH THE SYSTEM...BUT
SINCE THE H85 LOW IS OPENING UP AND BECOMING MORE PROGRESSIVE...AND
MOVING THROUGH QUICKLY...DO NOT EXPECT SIGNIFICANT PRECIPITATION.
HAVING SMALL CHANCE POPS IN THERE FOR THURSDAY NIGHT THROUGH FRIDAY
NIGHT SEEM JUSTIFIED DURING THIS TIME FRAME.
AFTER THE PERSISTENT TROUGHING KEEPS TEMPS ON THE COOLER SIDE OF
AVERAGE TO START THE WEEK...EXPECT WARMER READINGS THURSDAY INTO
FRIDAY WITH SOUTH-SOUTHWEST WINDS BTWN THE HIGH PRESSURE AND THE LOW
PRESSURE SYSTEM TO THE WEST. BASED ON 925-900MB TEMPS...SHOULD SEE
HIGHS ON THURSDAY REACH THE 30S WITH JUST A SMALL DROP IN READINGS
ON THURSDAY NIGHT IN WARM AIR ADVECTION AHEAD OF THE COLD FRONT.
TEMPERATURES ON FRIDAY PROBABLY REACH WELL INTO THE 30S. IF NOT FOR
A MOSTLY CLOUDY SKY...COULD EVEN SEE A FEW LOW-MID 40S WHERE MIXING
IS STRONGER. DID TWEAK TEMPS UPWARD NEAR LK SUPERIOR WITH DOWNSLOPE
WINDS FCST. TIGHTER PRESSURE GRADIENT WILL LEAD TO BREEZY CONDITIONS
THURSDAY NIGHT AND FRIDAY. TURNING BLUSTERY FOR SATURDAY FOLLOWING
THE COLD FRONT PASSAGE. TEMPS WILL NOT DROP TOO MUCH THOUGH...MAINLY
STAYING IN THE LOW-MID 30S...WHICH IS NEAR NORMAL FOR EARLY MARCH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1235 PM EST SAT MAR 2 2013
LAKE EFFECT CLOUDS WITH NORTH UPSLOPE WINDS WILL BRING MVFR
CONDITIONS TO ALL TAF SITES INTO THIS EVENING. MIXING AND
INCREASINGLY DIFLUENT FLOW SHOULD ALLOW CONDITIONS TO IMPROVE AT
CMX/IWD WITH VFR CONDITIONS TONIGHT INTO SUNDAY. HOWEVER...MVFR CIGS
ARE LIKELY TO PERSIST AT SAW TONIGHT AS INCREASING LOW-LVL
CONVERGENCE LEADS TO LAKE CLOUD FORMATION/FLURRIES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SAT MAR 2 2013
WINDS LESS THAN 20 KTS THROUGH MONDAY...THEN EXPECT NORTHEAST WINDS
TO INCREASE TO 30 KTS OVER WESTERN SECTIONS BY MONDAY NIGHT AS LOW
PRESSURE SYSTEM MOVES BY TO THE SOUTH OVER THE NORTHERN MISSISSIPPI
RIVER VALLEY. WINDS 20-30 KTS CONTINUE OVER MOST OF LK SUPERIOR
THROUGH TUESDAY BEFORE SETTLING DOWN TO LESS 20 KTS BY WEDNESDAY.
WINDS INCREASE TO 25 KTS FROM THE SOUTH THURSDAY NIGHT AND FRIDAY
AHEAD OF COLD FRONT. NO GALES ARE EXPECTED THIS WEEK...THOUGH COULD
SEE GALE GUSTS OVER WESTERN LK SUPERIOR MONDAY NIGHT CLOSER TO
MINNESOTA SHORELINE DUE TO COASTAL CONVERGENCE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
117 PM EST SAT MAR 2 2013
.SYNOPSIS...
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL BRING FAIR AND DRY BUT COLD WEATHER THROUGH THE
WEEKEND. TEMPERATURES WILL UNDERGO A GRADUAL MODERATING TREND FOR
THE UPCOMING WEEK WITH TRANQUIL WEATHER EXPECTED TO CONTINUE.
&&
.UPDATE...
ISSUED AT 956 AM EST SAT MAR 2 2013
I UPDATED THE Z0NES FOR MORE CLOUDINESS INTO SUNDAY. I ALSO ADDED
FLURRIES INTO THIS EVENING. THE LATEST SATELLITE LOOPS SHOW ONLY
THE AREA NEAR AND EAST OF US-131 AND SOUTH OF BIG RAPIDS HAVING
ANY SUNSHINE. ALL OF THE MODELS SHOW THE CLOUDS WILL FILL IN THERE
TOO AS THE THERMAL TROUGH MOVES THROUGH. MOST OF THE REPORTING
STATIONS NORTH AND EAST OF GRR HAVE FLURRIES AND OUR RADAR HAS
SOME WEAK RETURNS EAST OF THE OFFICE WHICH ARE INCREASING AND
MOVING TO THE SOUTH SOUTHWEST. GIVEN THE FLURRIES ALREADY THERE AND
THE RAP MODEL SUGGESTING .03 AT GRR BTW 18Z AND 06Z IT SEEMS
PRUDENT TO PUT AT LEAST A FEW FLURRIES IN THE FORECAST. IF THE
SNOW SHOWER ACTIVITY INCREASES THAN I WILL UPDATE AGAIN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL PRODUCE DRY BUT COLD WX THROUGH MONDAY WITH MAX
TEMPS THIS WEEKEND ONLY REACHING THE UPPER 20S TO LOWER 30S AND MIN
TEMPS MAINLY IN THE TEENS. SOME SINGLE DIGIT MINS ARE POSSIBLE THE
NEXT FEW NIGHTS NORTH OF I-96 GIVEN EXPANSIVE SNOW COVER AND
DEPENDENT LARGELY ON EXTENT OF CLEARING.
CURRENT IR SAT TREND CORROBORATED WITH 00Z NAM/GFS GUIDANCE TIME
HEIGHT RH PROGS SUGGEST WE WILL HAVE A MIX OF SUN AND CLOUDS TODAY
FOLLOWED BY A LITTLE MORE CLEARING TONIGHT. 00Z NUMERICAL GUIDANCE
AND TIME HEIGHT RH X-SECTIONS SUGGEST THE MOST EXTENSIVE CLEARING
SHOULD COME FOR MONDAY. THE EARLY MARCH SUNSHINE WILL HELP TO BOOST
MAX TEMPS INTO THE 30 TO 35 DEGREE RANGE MONDAY... WHICH IS STILL
SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 AM EST SAT MAR 2 2013
MAIN FOCUS OF THE LONG TERM IS ON THE SHORTWAVE SEEN SPINNING TOWARD
THE BRITISH COLUMBIA COAST IN THE GULF OF ALASKA. THE WAVE PROVIDES
THE ONLY POSSIBILITY OF PRECIPITATION IN THE LONG TERM. THE GFS AND
ECMWF ARE AT ODDS WITH ONE ANOTHER IN THE TRACK OF THE WAVE SO IT IS
FAR FROM CERTAIN AS TO WHETHER IT BRINGS SW LOWER MI ANY PRECIP. THE
GFS DRIVES IT INTO THE HEART OF THE WESTERN RIDGE...WHILE THE ECMWF
SLIDES IT OVER THE TOP OF THE RIDGE A BIT MORE. THE ECMWF SEEMS A
BIT MORE PLAUSIBLE AND RESULTS IN A FARTHER NORTH TRACK. HAVE THROWN
SOME SMALL POPS (20/30 PCT) BACK INTO THE FORECAST DURING THE MONDAY
NIGHT THROUGH TUESDAY NIGHT TIME FRAME. THE ECMWF WOULD EVEN IMPLY
SOME LIGHT ACCUMULATING SNOW TUESDAY NIGHT...A COUPLE INCHES
POTENTIALLY. WILL MONITOR THE TREND HERE...BUT WOULD NOT BE
SURPRISED TO SEE THE GFS DRIFT TOWARD THE ECMWF TRACK/EVOLUTION.
ALSO CAN SEE AN INCREASE IN POPS WITH TIME IF THE TREND HOLDS.
OTHERWISE...RIDGING BUILDS IN BEHIND THE EARLY WEEK SHORTWAVE
RESULTING IN MORE IN THE WAY OF SUNSHINE AND WARMING TEMPS.
TEMPERATURES WILL BE BACK TO AROUND NORMALS MID/LATE WEEK. HIGHS ON
FRIDAY SHOULD PUSH WELL INTO THE 40S...WITH 850MB TEMPS FORECAST TO
BE IN THE +3 TO +5 C RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 118 PM EST SAT MAR 2 2013
IT/S A TRICKY CLOUD FORECAST TODAY. THE WRN TAF SITES MAY SCATTER
OUT THIS AFTERNOON. LATEST VIS LOOP SHOWS THINNING CLOUDS OVER NW
LWR MI. HOWEVER...CLOUDS OVER LAKE MICHIGAN ARE ALSO MOVING SOUTH
AND MAY CLIP KMKG. ADDITIONALLY...MVFR CIGS ELSEWHERE KEEP
BOUNCING BETWEEN 1900-2100 FEET. KLAN/KJXN WILL LIKELY SEE THE
LOWER CIGS WHILE THE WRN TAF SITES WILL LIKELY SEE CIGS GREATER
THAN 2000 FT. KAZO SHOULD BE JUST FAR ENOUGH SOUTHWEST TO SEE
SCATTERED CLOUDS. IF A CIG DEVELOPS THERE IT LIKELY WON/T LAST
LONG.
&&
.MARINE...
ISSUED AT 956 AM EST SAT MAR 2 2013
THE WAVE MODEL SUGGESTS 3 TO 5 FOOT WAVES INTO SUNDAY MORNING NEAR
AND SOUTH OF HOLLAND SO I ISSUED A SMALL CRAFT ADVISORY TO COVER THIS.
I WILL ADMIT THE WEB CAMS DO NOT LOOK ALL THAT IMPRESSIVE BUT THERE
ARE NORTH WINDS AND THIS IS COLD AIR SO I WENT AHEAD WITH THIS ANYWAY.
ALSO IT MATCHES WHAT IWX HAD OUT.
&&
.HYDROLOGY...
ISSUED AT 315 AM EST SAT MAR 2 2013
THERE IS SOME POTENTIAL FOR INCREASING ICE ON THE MUSKEGON RIVER
THROUGH THE WEEKEND. HOWEVER WATER TEMPERATURES ON THE PINE AND
GRAND RIVERS ARE SEVERAL DEGREES ABOVE FREEZING SO ICE SHOULD BE
DECREASING. STRONGER MARCH SUNSHINE THE NEXT FEW DAYS MAY OFFSET ANY
INCREASE IN ICE AT NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR LMZ844>846.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...93
HYDROLOGY...LAURENS
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1245 PM EST SAT MAR 2 2013
.SYNOPSIS...
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL BRING FAIR AND DRY BUT COLD WEATHER THROUGH THE
WEEKEND. TEMPERATURES WILL UNDERGO A GRADUAL MODERATING TREND FOR
THE UPCOMING WEEK WITH TRANQUIL WEATHER EXPECTED TO CONTINUE.
&&
.UPDATE...
ISSUED AT 956 AM EST SAT MAR 2 2013
I UPDATED THE Z0NES FOR MORE CLOUDINESS INTO SUNDAY. I ALSO ADDED
FLURRIES INTO THIS EVENING. THE LATEST SATELLITE LOOPS SHOW ONLY
THE AREA NEAR AND EAST OF US-131 AND SOUTH OF BIG RAPIDS HAVING
ANY SUNSHINE. ALL OF THE MODELS SHOW THE CLOUDS WILL FILL IN THERE
TOO AS THE THERMAL TROUGH MOVES THROUGH. MOST OF THE REPORTING
STATIONS NORTH AND EAST OF GRR HAVE FLURRIES AND OUR RADAR HAS
SOME WEAK RETURNS EAST OF THE OFFICE WHICH ARE INCREASING AND
MOVING TO THE SOUTH SOUTHWEST. GIVEN THE FLURRIES ALREADY THERE AND
THE RAP MODEL SUGGESTING .03 AT GRR BTW 18Z AND 06Z IT SEEMS
PRUDENT TO PUT AT LEAST A FEW FLURRIES IN THE FORECAST. IF THE
SNOW SHOWER ACTIVITY INCREASES THAN I WILL UPDATE AGAIN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL PRODUCE DRY BUT COLD WX THROUGH MONDAY WITH MAX
TEMPS THIS WEEKEND ONLY REACHING THE UPPER 20S TO LOWER 30S AND MIN
TEMPS MAINLY IN THE TEENS. SOME SINGLE DIGIT MINS ARE POSSIBLE THE
NEXT FEW NIGHTS NORTH OF I-96 GIVEN EXPANSIVE SNOW COVER AND
DEPENDENT LARGELY ON EXTENT OF CLEARING.
CURRENT IR SAT TREND CORROBORATED WITH 00Z NAM/GFS GUIDANCE TIME
HEIGHT RH PROGS SUGGEST WE WILL HAVE A MIX OF SUN AND CLOUDS TODAY
FOLLOWED BY A LITTLE MORE CLEARING TONIGHT. 00Z NUMERICAL GUIDANCE
AND TIME HEIGHT RH X-SECTIONS SUGGEST THE MOST EXTENSIVE CLEARING
SHOULD COME FOR MONDAY. THE EARLY MARCH SUNSHINE WILL HELP TO BOOST
MAX TEMPS INTO THE 30 TO 35 DEGREE RANGE MONDAY... WHICH IS STILL
SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 AM EST SAT MAR 2 2013
MAIN FOCUS OF THE LONG TERM IS ON THE SHORTWAVE SEEN SPINNING TOWARD
THE BRITISH COLUMBIA COAST IN THE GULF OF ALASKA. THE WAVE PROVIDES
THE ONLY POSSIBILITY OF PRECIPITATION IN THE LONG TERM. THE GFS AND
ECMWF ARE AT ODDS WITH ONE ANOTHER IN THE TRACK OF THE WAVE SO IT IS
FAR FROM CERTAIN AS TO WHETHER IT BRINGS SW LOWER MI ANY PRECIP. THE
GFS DRIVES IT INTO THE HEART OF THE WESTERN RIDGE...WHILE THE ECMWF
SLIDES IT OVER THE TOP OF THE RIDGE A BIT MORE. THE ECMWF SEEMS A
BIT MORE PLAUSIBLE AND RESULTS IN A FARTHER NORTH TRACK. HAVE THROWN
SOME SMALL POPS (20/30 PCT) BACK INTO THE FORECAST DURING THE MONDAY
NIGHT THROUGH TUESDAY NIGHT TIME FRAME. THE ECMWF WOULD EVEN IMPLY
SOME LIGHT ACCUMULATING SNOW TUESDAY NIGHT...A COUPLE INCHES
POTENTIALLY. WILL MONITOR THE TREND HERE...BUT WOULD NOT BE
SURPRISED TO SEE THE GFS DRIFT TOWARD THE ECMWF TRACK/EVOLUTION.
ALSO CAN SEE AN INCREASE IN POPS WITH TIME IF THE TREND HOLDS.
OTHERWISE...RIDGING BUILDS IN BEHIND THE EARLY WEEK SHORTWAVE
RESULTING IN MORE IN THE WAY OF SUNSHINE AND WARMING TEMPS.
TEMPERATURES WILL BE BACK TO AROUND NORMALS MID/LATE WEEK. HIGHS ON
FRIDAY SHOULD PUSH WELL INTO THE 40S...WITH 850MB TEMPS FORECAST TO
BE IN THE +3 TO +5 C RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1241 PM EST SAT MAR 2 2013
LATEST VIS LOOP SHOWS CLOUDS BEGINNING TO SCATTER OUT ACROSS NRN
LWR. WE/RE THINKING THAT WILL OCCUR AT THE TAF SITES TOO LATER
TONIGHT. SCATTERED OUT THE CIGS OVERNIGHT. ERN TAF SITES SHOULD BE
THE LAST TO SCATTER OUT.
&&
.MARINE...
ISSUED AT 956 AM EST SAT MAR 2 2013
THE WAVE MODEL SUGGESTS 3 TO 5 FOOT WAVES INTO SUNDAY MORNING NEAR
AND SOUTH OF HOLLAND SO I ISSUED A SMALL CRAFT ADVISORY TO COVER THIS.
I WILL ADMIT THE WEB CAMS DO NOT LOOK ALL THAT IMPRESSIVE BUT THERE
ARE NORTH WINDS AND THIS IS COLD AIR SO I WENT AHEAD WITH THIS ANYWAY.
ALSO IT MATCHES WHAT IWX HAD OUT.
&&
.HYDROLOGY...
ISSUED AT 315 AM EST SAT MAR 2 2013
THERE IS SOME POTENTIAL FOR INCREASING ICE ON THE MUSKEGON RIVER
THROUGH THE WEEKEND. HOWEVER WATER TEMPERATURES ON THE PINE AND
GRAND RIVERS ARE SEVERAL DEGREES ABOVE FREEZING SO ICE SHOULD BE
DECREASING. STRONGER MARCH SUNSHINE THE NEXT FEW DAYS MAY OFFSET ANY
INCREASE IN ICE AT NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR LMZ844>846.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...93
HYDROLOGY...LAURENS
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1003 AM EST SAT MAR 2 2013
.SYNOPSIS...
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL BRING FAIR AND DRY BUT COLD WEATHER THROUGH THE
WEEKEND. TEMPERATURES WILL UNDERGO A GRADUAL MODERATING TREND FOR
THE UPCOMING WEEK WITH TRANQUIL WEATHER EXPECTED TO CONTINUE.
&&
.UPDATE...
ISSUED AT 956 AM EST SAT MAR 2 2013
I UPDATED THE Z0NES FOR MORE CLOUDINESS INTO SUNDAY. I ALSO ADDED
FLURRIES INTO THIS EVENING. THE LATEST SATELLITE LOOPS SHOW ONLY
THE AREA NEAR AND EAST OF US-131 AND SOUTH OF BIG RAPIDS HAVING
ANY SUNSHINE. ALL OF THE MODELS SHOW THE CLOUDS WILL FILL IN THERE
TOO AS THE THERMAL TROUGH MOVES THROUGH. MOST OF THE REPORTING
STATIONS NORTH AND EAST OF GRR HAVE FLURRIES AND OUR RADAR HAS
SOME WEAK RETURNS EAST OF THE OFFICE WHICH ARE INCREASING AND
MOVING TO THE SOUTH SOUTHWEST. GIVEN THE FLURRIES ALREADY THERE AND
THE RAP MODEL SUGGESTING .03 AT GRR BTW 18Z AND 06Z IT SEEMS
PRUDENT TO PUT AT LEAST A FEW FLURRIES IN THE FORECAST. IF THE
SNOW SHOWER ACTIVITY INCREASES THAN I WILL UPDATE AGAIN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 315 AM EST SAT MAR 2 2013
HIGH PRESSURE WILL PRODUCE DRY BUT COLD WX THROUGH MONDAY WITH MAX
TEMPS THIS WEEKEND ONLY REACHING THE UPPER 20S TO LOWER 30S AND MIN
TEMPS MAINLY IN THE TEENS. SOME SINGLE DIGIT MINS ARE POSSIBLE THE
NEXT FEW NIGHTS NORTH OF I-96 GIVEN EXPANSIVE SNOW COVER AND
DEPENDENT LARGELY ON EXTENT OF CLEARING.
CURRENT IR SAT TREND CORROBORATED WITH 00Z NAM/GFS GUIDANCE TIME
HEIGHT RH PROGS SUGGEST WE WILL HAVE A MIX OF SUN AND CLOUDS TODAY
FOLLOWED BY A LITTLE MORE CLEARING TONIGHT. 00Z NUMERICAL GUIDANCE
AND TIME HEIGHT RH X-SECTIONS SUGGEST THE MOST EXTENSIVE CLEARING
SHOULD COME FOR MONDAY. THE EARLY MARCH SUNSHINE WILL HELP TO BOOST
MAX TEMPS INTO THE 30 TO 35 DEGREE RANGE MONDAY... WHICH IS STILL
SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 AM EST SAT MAR 2 2013
MAIN FOCUS OF THE LONG TERM IS ON THE SHORTWAVE SEEN SPINNING TOWARD
THE BRITISH COLUMBIA COAST IN THE GULF OF ALASKA. THE WAVE PROVIDES
THE ONLY POSSIBILITY OF PRECIPITATION IN THE LONG TERM. THE GFS AND
ECMWF ARE AT ODDS WITH ONE ANOTHER IN THE TRACK OF THE WAVE SO IT IS
FAR FROM CERTAIN AS TO WHETHER IT BRINGS SW LOWER MI ANY PRECIP. THE
GFS DRIVES IT INTO THE HEART OF THE WESTERN RIDGE...WHILE THE ECMWF
SLIDES IT OVER THE TOP OF THE RIDGE A BIT MORE. THE ECMWF SEEMS A
BIT MORE PLAUSIBLE AND RESULTS IN A FARTHER NORTH TRACK. HAVE THROWN
SOME SMALL POPS (20/30 PCT) BACK INTO THE FORECAST DURING THE MONDAY
NIGHT THROUGH TUESDAY NIGHT TIME FRAME. THE ECMWF WOULD EVEN IMPLY
SOME LIGHT ACCUMULATING SNOW TUESDAY NIGHT...A COUPLE INCHES
POTENTIALLY. WILL MONITOR THE TREND HERE...BUT WOULD NOT BE
SURPRISED TO SEE THE GFS DRIFT TOWARD THE ECMWF TRACK/EVOLUTION.
ALSO CAN SEE AN INCREASE IN POPS WITH TIME IF THE TREND HOLDS.
OTHERWISE...RIDGING BUILDS IN BEHIND THE EARLY WEEK SHORTWAVE
RESULTING IN MORE IN THE WAY OF SUNSHINE AND WARMING TEMPS.
TEMPERATURES WILL BE BACK TO AROUND NORMALS MID/LATE WEEK. HIGHS ON
FRIDAY SHOULD PUSH WELL INTO THE 40S...WITH 850MB TEMPS FORECAST TO
BE IN THE +3 TO +5 C RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 656 AM EST SAT MAR 2 2013
MAIN AVIATION CONCERN THE NEXT 24 HOURS HOURS...WILL BE THE SAME
AS THE PREVIOUS 24 HOURS...VARIABLE CEILINGS. CLOUDS WILL VARY
BETWEEN SCT-OVC DOWN WIND OF THE GREAT LAKES IN NORTH TO
NORTHWEST FLOW. IN ADDITION THE CEILING HEIGHTS WILL VARY BETWEEN
MVFR (1800-3000FT) AND VFR (3100-4000FT).
IN GENERAL...CEILINGS WILL BE A BIT LOWER TODAY (MVFR) AND TREND
VFR TONIGHT AS CLOUDS LIFT A BIT AND EVEN TRY TO SCATTER OUT.
&&
.MARINE...
ISSUED AT 956 AM EST SAT MAR 2 2013
THE WAVE MODEL SUGGESTS 3 TO 5 FOOT WAVES INTO SUNDAY MORNING NEAR
AND SOUTH OF HOLLAND SO I ISSUED A SMALL CRAFT ADVISORY TO COVER THIS.
I WILL ADMIT THE WEB CAMS DO NOT LOOK ALL THAT IMPRESSIVE BUT THERE
ARE NORTH WINDS AND THIS IS COLD AIR SO I WENT AHEAD WITH THIS ANYWAY.
ALSO IT MATCHES WHAT IWX HAD OUT.
&&
.HYDROLOGY...
ISSUED AT 315 AM EST SAT MAR 2 2013
THERE IS SOME POTENTIAL FOR INCREASING ICE ON THE MUSKEGON RIVER
THROUGH THE WEEKEND. HOWEVER WATER TEMPERATURES ON THE PINE AND
GRAND RIVERS ARE SEVERAL DEGREES ABOVE FREEZING SO ICE SHOULD BE
DECREASING. STRONGER MARCH SUNSHINE THE NEXT FEW DAYS MAY OFFSET ANY
INCREASE IN ICE AT NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR LMZ844>846.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...LAURENS
MARINE...WDM
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
933 PM CST SUN MAR 3 2013
.UPDATE...
ISSUED AT 930 PM CST SUN MAR 3 2013
GOING FORECAST FOR A THREAT OF A LIGHT WINTRY MIX ACROSS OUR NE
COUNTIES STILL LOOKS ON THE MARK...AS REGIONAL RADAR LOOP HAS BEEN
INDICATING RELATIVELY NARROW BAND OF WAA-INDUCED PRECIP GRADUALLY
WORKING SE FROM CENTRAL IOWA. LATEST RUC AND 00Z NAM ARE STILL
SUGGESTING PTYPE WILL BE MOSTLY SNOW AT ONSET...BUT SHOULD
BECOME MIXED WITH AND TRANSITION TO SLEET AND FREEZING RAIN AS
ELEVATED WARM LAYER DEEPENS OVERNIGHT. FORTUNATELY PRECIP WILL
LIKELY BE SOMEWHAT HIT AND MISS...QUITE LIGHT... AND SHOULD ONLY
LAST AN HOUR OR SO...THEREFORE NO HEADLINES PLANNED ATTM.
ONE CHANGE TO GOING FORECAST WAS TO EXPAND THE SLIGHT CHANCE POPS
FURTHER S INTO THE STL AREA. MID LEVEL ECHO HAS BEEN EXPANDING
FROM BETWEEN IRK AND COU OVER THE LAST HOUR OR SO...AND BELIEVE
THAT SUBTLE INCREASE IN LIFT INTO THE MID MISSISSIPPI VALLEY MAY
BE JUST ENOUGH TO GET SOME PRECIP JUST S OF THE I-70 CORRIDOR.
IN THIS AREA...HAVE KEPT PTYPE AS ALL RAIN.
TRUETT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 301 PM CST SUN MAR 3 2013
FOCUS TONIGHT WILL BE PRECIP CHANCES.
STRONG WAA OVER THE REGION HAS MANAGED TO KEEP CLOUDS IN PLACE
THRU THE DAY. THIS IS ALSO RESPONSIBLE FOR THE AREA OF LIGHT SHSN OVER
ERN MO THAT HAS DEVELOPED OVER THE PAST FEW HOURS. MDLS SHOW
STRONG FORCING OVER THIS REGION THRU THIS AFTERNOON.
HOWEVER...THIS FORCING BECOMES RATHER DIFFUSE THIS EVENING...BUT
HAVE LOW SLIGHT CHANCE POPS THRU EARLY THIS EVENING TO ACCOUNT FOR
THIS. BELIEVE IT WILL MAINTAIN THE CURRENT TRACK TO THE SE AND
PROBABLY DISSIPATE BEFORE IT REACHES SERN PORTIONS OF THE CWA.
LATER TONIGHT...A SEPARATE WAA BAND MAY DEVELOP FAR ENUF TO THE SE
THAT IT WILL IMPACT NRN PORTIONS OF THE CWA. HAVE TRENDED TWD THE
GEM/ECMWF/GFS SOLNS AS THESE MDLS SEEM TO HAVE A BETTER HANDLE ON
THE CURRENT SITUATION. CONTINUE A MIX OF P-TYPES TONIGHT BASED ON
GFS PROGD SOUNDINGS AND UNCERTAINTY IN PLACEMENT OF PRECIP.
BELIEVE BULK OF PRECIP WILL BE SN UNTIL JUST BEFORE SUNRISE WHEN
MDLS WARM MID LVLS ENUF THAT IP OR FZRA WILL BE POSSIBLE.
HOWEVER...THIS IS ALSO THE TIME WHEN PRECIP IS MOST LIKELY. FOR
NOW...HAVE LIGHT ACCUMULATION OF SN/IP AS WELL AS A GLAZING OF
ICE.
&&
.LONG TERM...(MONDAY THROUGH NEXT SUNDAY)
ISSUED AT 334 PM CST SUN MAR 3 2013
(MONDAY THROUGH WEDNESDAY)
THE ONGOING NW/SE ORIENTED BAND OF PRECIPITATION DRIVEN THROUGH LOW
LEVEL WAA AND FRONTOGENTETIC FORCING SHOULD HAVE EITHER EXITED THE
CWA OR BE ON THE FAR FRINGES OF THE SOUTH CENTRAL IL COUNTIES AT
DAYBREAK ON MONDAY. MODEL SOUNDINGS OVERNIGHT TONIGHT THROUGH MONDAY
MORNING SHOW THAT STRONG LOW LEVEL WAA WILL CONTINUOUSLY ERODE THE
COLD AIR AS AN ELEVATED WARM LAYER DEVELOPS. THERMAL PROFILES AT 12Z
WITHIN THE PRECIPITATION THREAT AREA SHOW ONLY A SURFACE-BASED
SUBFREEZING COLD LAYER FROM 1-2KFT DEEP...SUGGESTIVE OF FREEZING
RAIN AND POSSIBLY SLEET AS A PTYPE. BY 15Z THE PRECIPITATION THREAT
APPEARS WELL REMOVED TO THE EAST AND THE ENTIRE LOWER TROP ACROSS
THE REGION IS WARMING. I THINK UNTIL MID-LATE AFTERNOON THERE WILL
JUST BE AN ABUNDANCE OF CLOUDS...BUT AFTER 21Z OR SO THERE COULD BE
SOME SPOTTY RAIN/SHOWERS ACROSS SE MO AND SRN IL AND ACROSS FAR NRN
MO INTO WEST CENTRAL IL. TEMPERATURES REMAIN A TOUGH CALL DUE TO THE
CLOUDS AND EXISTING SNOW COVER AND TEMPERED THEM BACK A BIT FROM
GUIDANCE OVER THE DEEPER SNOW PACK FROM CENTRAL MO THRU WEST CENTRAL
IL WHILE LETTING THEM WARM SUBSTANTIALLY ACROSS SRN MO.
THE BIGGEST ITEM OF INTEREST DURING THIS PERIOD IS THE UPPER LOW
CURRENTLY MOVING INTO THE UPPER ROCKIES. WE HAVE BEEN CAREFULLY
MONITORING THIS POTENT UPPER SYSTEM AND POTENTIAL IMPACTS MONDAY
NIGHT INTO TUESDAY AS IT MOVES THROUGH THE MID MS VALLEY. DESPITE
THE SYSTEM BEING ONSHORE NOW AND APPARENTLY WELL SAMPLED BY THE NOAM
UPPER AIR NETWORK...THERE REMAINS SIGNIFICANT DIFFERENCES WITH
RESPECT TO THE TRACK/POSITION AND EVEN TIMING OF THE UPPER
LOW...WITH POSITION DIFFERENCES ON THE ORDER OF 200 MILES BY 00Z
WED. THERE IS A GENERAL CONSENSUS THAT THE HEAVIEST SNOW BAND WILL
BE FROM NRN IA THRU NRN/CNTRL IL...HOWEVER THE EXTENT OF LIGHT TO
MODERATE SNOW FURTHER TO THE SOUTHWEST AND THRU OUR CWA IS MORE
QUESTIONABLE DUE TO THESE POSITION VARIANCES. THIS FORECAST GIVES
CREDENCE TO THE RANGE OF SOLUTIONS INCLUDING THE MORE SRN POSITIONS
OF THE UKMET AND ECMWF. STRONG CAA AND GUSTY NW WINDS IN THE WAKE
OF THE ASSOCIATED LOW LEVEL/SURFACE CYCLONES SHOULD BRING DEEPENING
COLD AIR FROM NW TO SE ACROSS THE CWA LATE MONDAY NIGHT INTO EARLY
TUESDAY SUPPORTING A CHANGE FROM RAIN TO SNOW. THE PRECIPITATION
THREAT WILL BE A RESULT OF STRONG MID/UPPER LEVEL FORCING ASSOCIATED
WITH THE MID/UPPER LOW AND VORT MAX MOVING TO ITS SOUTH. IN ADDITION
TO THE SNOWFALL WILL BE STRONG AND GUSTY NW WINDS. BY MID EVENING ON
TUESDAY THE SYSTEM AND ANY MEASURABLE SNOWFALL POTENTIAL SHOULD HAVE
EXITED TO THE EAST. CURRENTLY I HAVE SNOWFALL ACCUMULATIONS RANGING
FROM 2-3 INCHES IN NE MO AND WEST CENTRAL IL TAPERING TO JUST OVER
AN INCH THRU METRO ST LOUIS. THESE AMOUNTS WILL BE A BIT ON THE
LIGHT SIDE IF THE ECMWF AND UKMET PAN OUT. HIGH PRESSURE WILL THEN
BUILD INTO THE AREA LATE WEDNESDAY AND DOMINATE ON WED NIGHT.
(THURSDAY THROUGH SUNDAY)
BIG PATTERN CHANGE TO EVOLVE DURING THIS PERIOD WITH A TRANSITION TO
AN AMPLIFIED BUT PROGRESSIVE SPLIT FLOW REGIME. THE UPPER LOW/TROF
EXITS QUICKLY EASTWARD INTO THE ATLANTIC BY LATE THURSDAY WITH LARGE
HEIGHT RISES ALOFT IN ITS WAKE AS AN UPPER RIDGE BUILDS INTO THE MS
VALLEY AND AN UPPER LOW/TROF DIGS INTO THE WEST COAST. IN RESPONSE
WE SHOULD SEE A NICE WARM-UP IN TEMPERATURES TO ABOVE AVERAGE LEVELS
AS WE GET INTO SOUTHERLY RETURN FLOW AND H85 TEMPERATURES RISE TO +6
TO +10 DEGC BY LATE FRIDAY. THE UPPER RIDGE THEN SHIFTS INTO THE
EASTERN U.S. DURING THE WEEKEND AS THE UPPER LOW/TROF MOVES INTO THE
SWRN U.S...WHILE A THE SRN EXTENSION OF AN UPPER TROF/LOW OVER
CANADA TRANSLATES ACROSS THE UPPER MS VALLEY INTO THE NERN U.S. THIS
LATER FEATURE WILL RESULT IN AN EAST-WEST ORIENTED COLD FRONT
DIPPING DOWN INTO THE REGION AND BI-SECTING THE CWA. THE PRESENCE OF
THE FRONTAL BOUNDARY COMBINED WITH INCREASING MOISTURE AND LIFT IN
ADVANCE OF THE SWRN U.S. SYSTEM SHOULD BRING AN INCREASING THREAT OF
RAIN THRU THE WEEKEND.
GLASS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 545 PM CST SUN MAR 3 2013
SURFACE RIDGE HAS MOVED OFF TO THE EAST WITH NEXT WEATHER SYSTEM
APPROACHING THE AREA. MID AND HIGH CLOUDS TO PERSIST OVER REGION
THROUGH FORECAST PERIOD WITH SOUTHEAST WINDS...GRADUALLY
INCREASING TO AROUND 15 KTS BY MID MORNING ON MONDAY. TIMING OF
ONSET OF PCPN HARD TO PIN DOWN...SO FOR NOW JUST HAVE CIGS
LOWERING TO LOW END VFR BY MONDAY AFTERNOON.
SPECIFICS FOR KSTL...SURFACE RIDGE HAS MOVED OFF TO THE EAST WITH
NEXT WEATHER SYSTEM APPROACHING THE AREA. MID AND HIGH CLOUDS TO
PERSIST OVER REGION THROUGH FORECAST PERIOD WITH SOUTHEAST
WINDS...GRADUALLY INCREASING TO AROUND 15 KTS BY 13Z MONDAY.
TIMING OF ONSET OF PCPN HARD TO PIN DOWN...SO FOR NOW JUST HAVE
CIGS LOWERING TO LOW END VFR BY 23Z MONDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1046 PM CST FRI MAR 1 2013
.UPDATE...
ISSUED AT 928 PM CST FRI MAR 1 2013
SEEMINGLY NON-STOP...ALBEIT VERY LIGHT...SNOW CONTINUES TO FALL
OVER THE CWA THIS EVENING...WITH ANOTHER BAND OF 10-20DBZ ECHOES
NOW GROWING FROM THE UIN AREA SOUTH TO NEAR THE I-70 CORRIDOR.
A FEW SPOTS COULD STILL SEE A DUSTING OF SNOW BUT FOR MOST OF THE
AREA THINK THE SNOW WILL BE MORE ALONG THE LINE OF FLURRIES...AND
WILL CONTINUE THEM THROUGHOUT THE NIGHT.
OTHER QUESTION IS IF THERE WILL BE ANY CLEARING OVERNIGHT. IR SATELLITE
PICS INDICATE SOME HOLES HAVE FORMED IN THE CLOUDS OVER E MO...BUT
MORE SIGNIFICANT CLEARING AREA IS WORKING S FROM EASTERN
IOWA...AND 900MB RUC RH FORECASTS SEEM TO HAVE A GOOD HANDLE ON
THIS CLEARING LINE. WILL WORK THIS CLEARING..AND DROP MENTION OF
FLURRIES...INTO OUR FAR N COUNTIES INCLUDING UIN...DURING THE
PREDAWN HOURS. WILL ALSO LOWER TEMPS A FEW DEGREES IN THIS PART
OF THE CWA TO ACCOUNT FOR THIS LATE NIGHT CLEARING.
TRUETT
&&
.SHORT TERM...(THROUGH TONIGHT)
ISSUED AT 213 PM CST FRI MAR 1 2013
FOCUS THRU THE PERIOD WILL BE PRECIP CHANCES.
POPS FOR TONIGHT WILL BE A LAST MIN DECISION BASED ON LATEST RADAR
TRENDS. WITH LITTLE IN THE WAY OF FORCING OR SOMETHING TO TRACK FOR
THE SN TONIGHT...WILL BE DIFFICULT TO PIN DOWN EXACTLY WHAT AREAS
WILL SEE LIGHT SN VERSUS FLURRIES AND NOTHING AT ALL. LATEST MDL
GUIDANCE SUGGESTS BEST CHANCES WILL BE IN FAR SRN PORTIONS OF THE
CWA AND PERHAPS A CONTINUING BAND IN CNTL MO. ELSEWHERE...FLURRIES
MAY PERSIST THRU MUCH OF THE EVENING HOURS. CAN NOT COMPLETELY RULE
OUT FLURRIES CONTINUING AFTER MIDNIGHT...BUT SHUD BE CONFINED TO FAR
SRN PORTIONS OF THE CWA IF THEY OCCUR THAT LATE.
WHILE SOME MDL GUIDANCE SUGGESTS CLOUDS DISSIPATING LATE
TONIGHT...GIVEN EXTENSIVE CLOUD COVER UPSTREAM...BELIEVE THAT CLOUDS
WILL STRUGGLE TO DISSIPATE TONIGHT. HAVE THEREFORE CONTINUED A
PERSISTENCE FORECAST FOR TEMPS TONIGHT.
TILLY
&&
.LONG TERM...(SATURDAY THROUGH NEXT FRIDAY)
ISSUED AT 213 PM CST FRI MAR 1 2013
(SATURDAY THROUGH TUESDAY)
FOCUS EARLY IN THE PERIOD WILL BE TEMPS AS THE SFC RIDGE BUILDS
INTO THE REGION. MDLS ARE GENERALLY IN GOOD AGREEMENT THRU SUN.
AS DISCUSSED ABOVE...EXPECT CLOUD COVER TO LINGER THRU MUCH OF THE
DAY SAT. HAVE THEREFORE TRENDED CLOSE TO PERSISTENCE KEEPING TEMPS
AOB THE COLDEST MOS THRU SAT NIGHT. WITH ONE BATCH OF CLOUDS MOVING
OUT OF THE REGION JUST BEFORE CI ASSOCIATED WITH THE NEXT SYSTEM
MOVES IN...SHUD BE A BRIEF TIME WHERE MUCH OF THE AREA IS CLOUD
FREE. WITH THE SFC RIDGE SETTING OVER THE REGION...GOOD
RADIATIONAL COOLING SHUD OCCUR.
FOCUS QUICKLY TURNS TO THE NEXT APPROACHING SYSTEM. MDL
DIFFERENCES BECOME APPARENT STARTING SUN. THERE ARE TWO BASIC
SOLNS AMONG THE MDLS. THE GFS/ECMWF/GEM IN ONE CAMP WITH THE
NAM/DGEX/LOCAL WRF IN THE OTHER. THE SREF AND GEFS MEAN ALSO TREND
AWAY FROM THE NAM SOLN LATE IN THE PERIOD. HAVE THEREFORE TRENDED
TWD THE GFS/ECMWF/GEM SOLNS. THIS RESULTS IN A WETTER FORECAST
WITH SIMILAR THERMAL PROFILES. GIVEN MDL PERFORMANCE WITH THIS
SYSTEM OVER THE PAST FEW DAYS...STILL HAVE SOMEWHAT LOW CONFIDENCE
IN ANY ONE SOLN.
WHILE THE ECMWF/GEM/GFS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN
THE PERIOD...DIFFERENCES BECOME GREATER BY TUES. THE GFS BECOMES A
FAST AND STRONG OUTLIER WITH THE UPPER LOW. THE GEFS MEAN ALSO
TRENDS SLOWER THAN THE OPERATIONAL SOLN. NOT COMPLETELY SURE WHAT
TO MAKE OF THE ECMWF SOLN WHICH HAS THE UPPER LOW SO FAR DETACHED
FROM THE SFC WAVE. WITH SUPPORT FROM THE GEM...HAVE INCREASED POPS
MON NIGHT AND TUES...BUT KEPT GENERAL RA/SN MIX WORDING FOR PRECIP
TYPE FOR NOW.
(WEDNESDAY THROUGH FRIDAY)
WITH LITTLE TO NO PRECIP ANTICIPATED DURING THIS PERIOD...FOCUS
WILL TURN TO TEMPS ONCE AGAIN.
WHAT DIFFERENCES THERE WERE...MDLS HAVE COME INTO A GENERAL
AGREEMENT THRU THIS PERIOD. WITH THE SFC RIDGE IN PLACE ON
WED...TRENDED TWD COOLER GUIDANCE. WITH THE SFC RIDGE MOVING OUT
OF THE AREA BY THURS AND RIDGING ALOFT...STARTED A QUICK WARMING
TREND THRU THE END OF THE PERIOD.
TILLY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1037 PM CST FRI MAR 1 2013
FLURRIES AND LIGHT SNOW WILL EVENTUALLY TAPER OFF OVERNIGHT
ALTHOUGH A BRIEF PD OF MVFR VSBYS WILL BE POSSIBLE IF AN ENHANCED
POCKET OF LIGHT SNOW MOVES DIRECTLY OVER ONE OF THE TAF SITES.
SPATIAL COVERAGE OF MVFR CIGS VARIED WIDELY AT TAF ISSUANCE
HOWEVER THERE WAS ALSO A CLEARING LINE APPROACHING FROM THE NORTH
WHICH WAS ASSOCIATED WITH THE ARRIVAL OF DRIER AIR. ATTM IT
APPEARS THAT THE BACK EDGE OF THE STRATOCU WILL REACH THE
TERMINALS TOMORROW MORNING ALTHOUGH IT IS POSSIBLE THAT THE
LINGERING SNOW COVER OVER NRN MO MAY SLOW DOWN ITS ARRIVAL.
SPECIFICS FOR KSTL...FLURRIES AND LIGHT SNOW WILL EVENTUALLY TAPER
OFF OVERNIGHT ALTHOUGH A BRIEF PD OF MVFR VSBYS WILL BE POSSIBLE
IF AN ENHANCED POCKET OF LIGHT SNOW MOVES DIRECTLY OVER THE
TERMINAL. CIGS SHOULD IMPROVE ONCE DRIER AIR WORKS INTO THE REGION
FROM THE NORTH. ATTM IT APPEARS THAT THE CLEARING LINE WILL REACH
KSTL LATE TOMORROW MORNING.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
711 PM CST SUN MAR 3 2013
.SYNOPSIS...
ISSUED AT 335 PM CST SUN MAR 3 2013
H5 ANALYSIS FROM THIS MORNING HAS A BROAD TROUGH OF LOW PRESSURE
OVER THE EASTERN SEA BOARD. RIDGING EXTENDED FROM THE FOUR CORNERS
NWD INTO EASTERN MT. FURTHER WEST...A STRONG SHORTWAVE TROUGH OF LOW
PRESSURE WAS TRACKING EAST INTO THE NORTHERN ROCKIES WITH 180 METER
HT FALLS NOTED AT SPOKANE WASHINGTON AND 130 METER FALLS AT GREAT
FALLS MT. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NWRN
NEBRASKA...WITH A FRONT EXTENDING SSE INTO SOUTH CENTRAL NEBRASKA. LIKE
YESTERDAY...A LARGE SPREAD IN TEMPERATURES WERE NOTED ACROSS
NEBRASKA...WITH 2 PM CST TEMPS RANGING FROM 38 AT OMAHA...TO 67
AT IMPERIAL.
&&
.UPDATE...
ISSUED AT 702 PM CST SUN MAR 3 2013
THE PACIFIC FRONT IS RIPPING APART NORTHEAST WY THIS EVENING WITH
A GUST TO 66 MPH AT BUFFALO. THE FRONT WILL ENTER WRN AND NCTNL
NEB TONIGHT. GUSTS SHOULD REACH 40 MPH...PERHAPS STRONGER.
A FEW COUNTIES HAVE BEEN ADDED TO THE WIND ADZY AS BLENDS OF
GEM...NAM...SREF AND MET/MAV SUGGESTED STRONGER WINDS. GIVEN THE
EVENTS THIS AFTN/EVENING ACROSS THE NRN HIGH PLAINS THIS ADDITION
SHOULD WORK. THE REST OF THE FCST IS VERY SIMILAR TO THE PREVIOUS.
RAIN AND SNOW SHOWERS ARE DEVELOPING ALONG THE PACIFIC FRONT AND
THESE SHOULD WORK THROUGH NRN NEB TONIGHT.
GIVEN THE UNCERTAINTIES OF THE FCST OVERNIGHT. THE BEST APPROACH
TO THE ONGOING HIGH WIND EVENT ACROSS THE NRN HIGH PLAINS WOULD
BE TO WATCH OBSERVATIONS CLOSELY FOR SIGNS OF WEAKENING. THE PV1.5
SFC IS EXPECTED TO REMAIN ON AN EASTERLY COURSE AFFECTING WRN SD
AND ND TONIGHT. THUS IT IS NOT SYNOPTICALLY EVIDENT THAT STRONG
OR HIGH WINDS WILL DEVELOP ACROSS WRN AND NCNTL NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH WINDS AND LIGHT
PRECIPITATION CHANCES OVER NORTHERN NEBRASKA.
THE SHORTWAVE TROUGH OVER WESTERN MONTANA WILL PUSH INTO THE DAKOTAS
THROUGH THE DAY MONDAY...BRINGING A DRAMATIC CHANGE TO THE LOCAL
WEATHER. AT THE SURFACE...THE FRONTAL BOUNDARY WILL STAY NEARLY
STATIONARY FROM CENTRAL SOUTH DAKOTA THROUGH SOUTH CENTRAL NEBRASKA
THROUGH MONDAY MORNING...BEFORE PUSHING EASTWARD BY THE END OF THE
DAY.
LOOKING AT PRECIPITATION WITH THE SYSTEM...THE BEST MOISTURE WILL
STAY UP ACROSS THE DAKOTAS WHERE THE SURFACE LOW WILL PASS. BUT WITH
THE LOCATION OF THE FRONT BEING OVER NORTH CENTRAL NEBRASKA...MAY
HAVE ENOUGH LIFT AND MOISTURE CONVERGENCE TO NEED SOME CHANCES FOR
PRECIPITATION OVER THE NORTH CENTRAL COUNTIES TONIGHT AND MONDAY
MORNING. THEN AS THE COLD FRONT MOVES THROUGH TONIGHT COULD GET A
BIT OF ENHANCED LIFT TO GIVE SOME LIGHT PRECIPITATION. WITH ONLY
LIMITED MOISTURE AND NO STRONG SIGNALS FOR GOOD PRECIPITATION
DEVELOPMENT LOCALLY...BELIEVE ANYTHING WILL BE VERY LIGHT...WITH
CHANCES FOR MEASURABLE PRECIPITATION BEING LOW. THE OTHER CONCERN IS
PRECIPITATION TYPE. THERE IS STRONG COLD AIR ADVECTION COMING BEHIND
THE FRONT TONIGHT AT 850MB...BUT AT THE SURFACE...TEMPERATURES DON/T
COOL REAL FAST. SO...WITH CURRENT TEMPERATURES IN THE 40S...50S AND
60S...WILL NEED SOME TIME TO GET THE COLDER AIR ACROSS THE AREA AND
KEPT A RAIN/SNOW MIX IN THE FORECAST THROUGH 09Z. AFTER
09Z...NORTHWEST NEBRASKA SHOULD HAVE COOLED ENOUGH FOR PRECIPITATION
TO BE SNOW...HOWEVER CLOSER TO THE FRONT OVER NORTH CENTRAL
NEBRASKA...FORECAST SOUNDINGS WERE SHOWING A SIGNAL FOR FREEZING
RAIN OR FREEZING DRIZZLE FOR A SHORT PERIOD. AS IT LOOKS LIKE THIS
WOULD OCCUR FOR A VERY SHORT PERIOD...NOT EXPECTING MUCH IF ANY ICE
ACCUMULATION...SO THREAT FOR HAZARDOUS TRAVEL SHOULD BE LOW. AFTER
12Z...TEMPERATURE PROFILES LOOK LIKE PRECIPITATION SHOULD CHANGE OVER
TO SNOW EVERYWHERE. THEN AS SURFACE TEMPERATURES WARM A BIT DURING
THE DAY...MAY AGAIN GET A CHANGEOVER TO RAIN/SNOW MIX OR RAIN.
FOR WINDS...AS THE COLD FRONT MOVES THROUGH TONIGHT...WITH HAVE
PRETTY SIGNIFICANT PRESSURE RISES SO HAVE INCREASED WINDS TONIGHT.
THE STRONGER WINDS ARE EXPECTED TO DEVELOP AROUND NOON-TIME MONDAY
ACROSS THE PANHANDLE AS THE PRESSURE GRADIENT TIGHTENS...COLD AIR
ADVECTION STRENGTHENS AND A DECENT PV ANOMALY MOVES ACROSS THE AREA.
AS THIS OCCURS...THE BOUNDARY LAYER SHOULD MIX TO AT LEAST
800MB...AND WITH UNIDIRECTIONAL WINDS GOING UPWARD...SHOULDN/T HAVE
A PROBLEM BRINGING DOWN THE STRONGER WINDS FROM ALOFT. JUST HOW
STRONG THEY WILL BE REMAINS A BIT OF A QUESTION. AS IS TYPICAL...THE
GFS AND MAV GUIDANCE IS STRONGER WITH THE WIND SPEEDS...WHILE THE
NAM AND MET GUIDANCE IS QUITE A BIT LESS. THE SIGNAL LOOKS GOOD
ENOUGH FOR AT LEAST MARGINAL WIND ADVISORY SPEEDS ACROSS THE
PANHANDLE STARTING AROUND MID-DAY...THEN TRANSITIONING ACROSS NORTH
CENTRAL NEBRASKA LATER INTO THE AFTERNOON AND EVENING. SO...HAVE
ISSUED A WIND ADVISORY FOR THOSE AREAS FOR MONDAY AFTERNOON INTO
MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
MONDAY NIGHT THROUGH WEDNESDAY...WINDS WILL BE THE MAIN
FORECAST CONCERN FROM MONDAY NIGHT INTO EARLY TUESDAY...THEN
TEMPERATURES ON TUESDAY AND WEDNESDAY AS AN ARCTIC AIRMASS PUSHES
SOUTH INTO THE CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY.
STRONG NORTHERLY WINDS WILL TRANSITION EAST FROM NORTHWESTERN
NEBRASKA MONDAY EVENING AS THE ARCTIC COLD FRONT PUSHES INTO NORTH
CENTRAL...THEN NORTHEASTERN NEBRASKA. LOW LEVEL COLD AIR ADVECTION
AND SURFACE PRESSURE RISES ARE MOST PRONOUNCED ACROSS THE N CENTRAL
CWA MONDAY EVENING WITH THE BEST WIND POTENTIAL IN THESE AREAS. GFS
BUFKIT SOUNDINGS ACROSS NORTHERN NEBRASKA...SUPPORT SUSTAINED WINDS
OF 30 TO 40 MPH...WITH GUSTS TO 50 MPH MONDAY EVENING...WHILE THE
NAM BUFKIT SOUNDINGS ARE ABOUT 5 TO 10 MPH SLOWER. WILL UTILIZE A
50/50 BLEND BETWEEN THE MAV AND MET WIND SPEEDS WHICH YIELDS WIND
SPEEDS OF 25 TO 35 MPH WITH GUSTS TO 45 MPH. DECIDED TO CARRY OVER
THE WIND ADVISORY INTO NORTH CENTRAL NEBRASKA THROUGH TUESDAY
MORNING. BY 12Z TUESDAY...LOW LEVEL COLD AIR ADVECTION WILL COME TO
AN END...WHILE THE CORE OF 30+KT 500 METER AGL WINDS...SHIFTS EAST
INTO NERN NEBRASKA. FURTHER WEST...WILL EXPIRE THE WIND ADVISORY
AROUND MIDNIGHT...AS LOW LEVEL CAA ENDS AND PRESSURE RISES END.
WINDS WILL DIMINISH FURTHER ON TUESDAY AS COLD ARCTIC HIGH PRESSURE
BUILDS INTO THE CENTRAL AND NORTHERN PLAINS. BASED ON H85
TEMPS...HIGHS TUESDAY WILL VARY WIDELY ACROSS THE FORECAST
AREA...WITH READINGS AROUND 30 IN THE NORTHEAST...TO THE LOWER 40S
IN SWRN NEBRASKA. HIGH PRESSURE WILL TRACK EAST ON TUESDAY NIGHT
WITH INCREASING SRLY WINDS FOR WEDNESDAY. WARMER TEMPERATURES WILL
BEGIN TO WORK INTO WESTERN NEBRASKA ON WEDNESDAY...HOWEVER...COLD
TEMPERATURES WILL REMAIN AT IN THE EASTERN CWA WITH HIGHS AROUND 40
FOR KONL...AND 42 FOR KANW. READINGS WILL BE IN THE LOWER 50S ACROSS
SWRN NEBRASKA AND THE EASTERN PANHANDLE. BASED ON FCST 500 METER
WINDS...SURFACE WIND SPEEDS ARE EXPECTED TO BE WELL BELOW ADVISORY
CRITERIA WEDS AFTERNOON.
WEDNESDAY NIGHT THROUGH SUNDAY...COLD AIR WILL SLIDE
EAST WITH THE HIGH WEDNESDAY NIGHT...AND SURFACE LOW PRESSURE WILL
DEEPEN OVER EASTERN COLORADO. SRLY WINDS WILL INCREASE...ALONG WITH
TEMPERATURES AS THE ARCTIC AIR MASS SHIFTS EAST OF THE AREA. FCST
H85 TEMPS WILL INCREASE TO 8 TO 12 C THURSDAY AFTERNOON AHEAD OF A
APPG COLD FRONT. THE COMBINATION OF THE APPG COLD FRONT...SRLY
WINDS...AND RIDGING ALOFT...WILL RESULT IN HIGHS IN THE 50S TO LOWER
60S THURSDAY. AFTER ONE DAY OF WARM TEMPERATURES...MUCH COOLER
TEMPERATURES AND THE POTENTIAL FOR A POTENT WINTER STORM...WILL
BEGIN TO PUSH ACROSS SRN ROCKIES ONTO THE CENTRAL AND SRN PLAINS
FRIDAY NIGHT INTO SATURDAY. SOME TRACK DIFFERENCES EXIST BETWEEN THE
GFS AND EC MODEL RUNS THIS MORNING. THE GFS REMAINS SOUTH...WITH THE
ECMWF BEING FURTHER NORTH. BOTH SOLUTIONS PUSH COLD FRONT INTO THE
FORECAST AREA EITHER FRIDAY NIGHT OR SATURDAY DEPENDING ON MODEL
CHOICE. THE RESULTANT AIRMASS BEHIND THE FRONT WILL BE A SHALLOW SUB
FREEZING LAYER...WITH DECENT MID LEVEL ASCENT NOTED ABOVE THIS
LAYER. WOULDN`T BE SURPRISED TO SEE A MIX OF PCPN ACROSS THE NORTH
FOR FRIDAY INTO FRIDAY NIGHT. HOWEVER...GIVEN THE MODEL DIFFERENCES
WITH THE TIMING OF THE FRONT...DECIDED TO WORD PRECIPITATION MENTION
AS RAIN OR SNOW ATTM. THIS WILL CARRY OVER INTO THE WEEKEND WITH
HIGHS IN THE 30S AND LOWS IN THE 20S. ATTM...THE EXTENDED BEYOND
THURSDAY REMAINS A LOW CONFIDENCE FCST...IN PARTICULAR PRECIPITATION
TYPE...AS POOR MODEL AGREEMENT IS NOTED. NO DOUBT...WE COULD SEE
SOME PRECIPITATION NEXT WEEKEND GIVEN THE CURRENT EC AND GFS
SOLNS...AND CHANCE POPS REFLECT THAT IN THE CURRENT FCST. BASED ON
EITHER SOLUTION...WE COULD BE DEALING WITH LIGHT PRECIPITATION...OR
A SIGNIFICANT SNOW STORM (12Z ECMWF SOLUTION). WILL NEED TO MONITOR
THIS CLOSELY OVER THE NEXT FEW DAYS AS WE GRAVITATE TOWARD
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 524 PM CST SUN MAR 3 2013
A POWERFUL PACIFIC COLD FRONT...CURRENTLY MOVING THROUGH SERN
MT...WILL APPROACH KVTN AROUND 07Z-09Z. THE FRONT HAS THE
POTENTIAL TO PRODUCE STRONG WIND GUSTS AND MVFR AS IT SWEEPS THE FCST
AREA OVERNIGHT. THE HRRR MODEL INDICATES THE FRONT WILL HIT KVTN
AROUND 07Z AND PRODUCE WIND GUSTS OVER 50KT SO WE WILL BE
MONITORING THE FRONT AS IT MOVES THROUGH WRN SD THIS EVENING.
OTHERWISE VFR IS EXPECTED MONDAY. WINDS ARE EXPECTED TO INCREASE
T0 31028G42KT DURING THE LATE MORNING WEST...AND DURING THE AFTN
EAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CST /11 AM MST/ MONDAY TO MIDNIGHT CST
/11 PM MST/ MONDAY NIGHT FOR NEZ004-022>024-035-036-056>058-069-
094.
WIND ADVISORY FROM 3 PM MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR
NEZ059-070.
WIND ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
NEZ005>010-025>029-037-038.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
528 PM CST SUN MAR 3 2013
.SYNOPSIS...
ISSUED AT 335 PM CST SUN MAR 3 2013
H5 ANALYSIS FROM THIS MORNING HAS A BROAD TROUGH OF LOW PRESSURE
OVER THE EASTERN SEA BOARD. RIDGING EXTENDED FROM THE FOUR CORNERS
NWD INTO EASTERN MT. FURTHER WEST...A STRONG SHORTWAVE TROUGH OF LOW
PRESSURE WAS TRACKING EAST INTO THE NORTHERN ROCKIES WITH 180 METER
HT FALLS NOTED AT SPOKANE WASHINGTON AND 130 METER FALLS AT GREAT
FALLS MT. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NWRN
NEBRASKA...WITH A FRONT EXTENDING SSE INTO SOUTH CENTRAL NEBRASKA. LIKE
YESTERDAY...A LARGE SPREAD IN TEMPERATURES WERE NOTED ACROSS
NEBRASKA...WITH 2 PM CST TEMPS RANGING FROM 38 AT OMAHA...TO 67
AT IMPERIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH WINDS AND LIGHT
PRECIPITATION CHANCES OVER NORTHERN NEBRASKA.
THE SHORTWAVE TROUGH OVER WESTERN MONTANA WILL PUSH INTO THE DAKOTAS
THROUGH THE DAY MONDAY...BRINGING A DRAMATIC CHANGE TO THE LOCAL
WEATHER. AT THE SURFACE...THE FRONTAL BOUNDARY WILL STAY NEARLY
STATIONARY FROM CENTRAL SOUTH DAKOTA THROUGH SOUTH CENTRAL NEBRASKA
THROUGH MONDAY MORNING...BEFORE PUSHING EASTWARD BY THE END OF THE
DAY.
LOOKING AT PRECIPITATION WITH THE SYSTEM...THE BEST MOISTURE WILL
STAY UP ACROSS THE DAKOTAS WHERE THE SURFACE LOW WILL PASS. BUT WITH
THE LOCATION OF THE FRONT BEING OVER NORTH CENTRAL NEBRASKA...MAY
HAVE ENOUGH LIFT AND MOISTURE CONVERGENCE TO NEED SOME CHANCES FOR
PRECIPITATION OVER THE NORTH CENTRAL COUNTIES TONIGHT AND MONDAY
MORNING. THEN AS THE COLD FRONT MOVES THROUGH TONIGHT COULD GET A
BIT OF ENHANCED LIFT TO GIVE SOME LIGHT PRECIPITATION. WITH ONLY
LIMITED MOISTURE AND NO STRONG SIGNALS FOR GOOD PRECIPITATION
DEVELOPMENT LOCALLY...BELIEVE ANYTHING WILL BE VERY LIGHT...WITH
CHANCES FOR MEASURABLE PRECIPITATION BEING LOW. THE OTHER CONCERN IS
PRECIPITATION TYPE. THERE IS STRONG COLD AIR ADVECTION COMING BEHIND
THE FRONT TONIGHT AT 850MB...BUT AT THE SURFACE...TEMPERATURES DON/T
COOL REAL FAST. SO...WITH CURRENT TEMPERATURES IN THE 40S...50S AND
60S...WILL NEED SOME TIME TO GET THE COLDER AIR ACROSS THE AREA AND
KEPT A RAIN/SNOW MIX IN THE FORECAST THROUGH 09Z. AFTER
09Z...NORTHWEST NEBRASKA SHOULD HAVE COOLED ENOUGH FOR PRECIPITATION
TO BE SNOW...HOWEVER CLOSER TO THE FRONT OVER NORTH CENTRAL
NEBRASKA...FORECAST SOUNDINGS WERE SHOWING A SIGNAL FOR FREEZING
RAIN OR FREEZING DRIZZLE FOR A SHORT PERIOD. AS IT LOOKS LIKE THIS
WOULD OCCUR FOR A VERY SHORT PERIOD...NOT EXPECTING MUCH IF ANY ICE
ACCUMULATION...SO THREAT FOR HAZARDOUS TRAVEL SHOULD BE LOW. AFTER
12Z...TEMPERATURE PROFILES LOOK LIKE PRECIPITATION SHOULD CHANGE OVER
TO SNOW EVERYWHERE. THEN AS SURFACE TEMPERATURES WARM A BIT DURING
THE DAY...MAY AGAIN GET A CHANGEOVER TO RAIN/SNOW MIX OR RAIN.
FOR WINDS...AS THE COLD FRONT MOVES THROUGH TONIGHT...WITH HAVE
PRETTY SIGNIFICANT PRESSURE RISES SO HAVE INCREASED WINDS TONIGHT.
THE STRONGER WINDS ARE EXPECTED TO DEVELOP AROUND NOON-TIME MONDAY
ACROSS THE PANHANDLE AS THE PRESSURE GRADIENT TIGHTENS...COLD AIR
ADVECTION STRENGTHENS AND A DECENT PV ANOMALY MOVES ACROSS THE AREA.
AS THIS OCCURS...THE BOUNDARY LAYER SHOULD MIX TO AT LEAST
800MB...AND WITH UNIDIRECTIONAL WINDS GOING UPWARD...SHOULDN/T HAVE
A PROBLEM BRINGING DOWN THE STRONGER WINDS FROM ALOFT. JUST HOW
STRONG THEY WILL BE REMAINS A BIT OF A QUESTION. AS IS TYPICAL...THE
GFS AND MAV GUIDANCE IS STRONGER WITH THE WIND SPEEDS...WHILE THE
NAM AND MET GUIDANCE IS QUITE A BIT LESS. THE SIGNAL LOOKS GOOD
ENOUGH FOR AT LEAST MARGINAL WIND ADVISORY SPEEDS ACROSS THE
PANHANDLE STARTING AROUND MID-DAY...THEN TRANSITIONING ACROSS NORTH
CENTRAL NEBRASKA LATER INTO THE AFTERNOON AND EVENING. SO...HAVE
ISSUED A WIND ADVISORY FOR THOSE AREAS FOR MONDAY AFTERNOON INTO
MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
MONDAY NIGHT THROUGH WEDNESDAY...WINDS WILL BE THE MAIN
FORECAST CONCERN FROM MONDAY NIGHT INTO EARLY TUESDAY...THEN
TEMPERATURES ON TUESDAY AND WEDNESDAY AS AN ARCTIC AIRMASS PUSHES
SOUTH INTO THE CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY.
STRONG NORTHERLY WINDS WILL TRANSITION EAST FROM NORTHWESTERN
NEBRASKA MONDAY EVENING AS THE ARCTIC COLD FRONT PUSHES INTO NORTH
CENTRAL...THEN NORTHEASTERN NEBRASKA. LOW LEVEL COLD AIR ADVECTION
AND SURFACE PRESSURE RISES ARE MOST PRONOUNCED ACROSS THE N CENTRAL
CWA MONDAY EVENING WITH THE BEST WIND POTENTIAL IN THESE AREAS. GFS
BUFKIT SOUNDINGS ACROSS NORTHERN NEBRASKA...SUPPORT SUSTAINED WINDS
OF 30 TO 40 MPH...WITH GUSTS TO 50 MPH MONDAY EVENING...WHILE THE
NAM BUFKIT SOUNDINGS ARE ABOUT 5 TO 10 MPH SLOWER. WILL UTILIZE A
50/50 BLEND BETWEEN THE MAV AND MET WIND SPEEDS WHICH YIELDS WIND
SPEEDS OF 25 TO 35 MPH WITH GUSTS TO 45 MPH. DECIDED TO CARRY OVER
THE WIND ADVISORY INTO NORTH CENTRAL NEBRASKA THROUGH TUESDAY
MORNING. BY 12Z TUESDAY...LOW LEVEL COLD AIR ADVECTION WILL COME TO
AN END...WHILE THE CORE OF 30+KT 500 METER AGL WINDS...SHIFTS EAST
INTO NERN NEBRASKA. FURTHER WEST...WILL EXPIRE THE WIND ADVISORY
AROUND MIDNIGHT...AS LOW LEVEL CAA ENDS AND PRESSURE RISES END.
WINDS WILL DIMINISH FURTHER ON TUESDAY AS COLD ARCTIC HIGH PRESSURE
BUILDS INTO THE CENTRAL AND NORTHERN PLAINS. BASED ON H85
TEMPS...HIGHS TUESDAY WILL VARY WIDELY ACROSS THE FORECAST
AREA...WITH READINGS AROUND 30 IN THE NORTHEAST...TO THE LOWER 40S
IN SWRN NEBRASKA. HIGH PRESSURE WILL TRACK EAST ON TUESDAY NIGHT
WITH INCREASING SRLY WINDS FOR WEDNESDAY. WARMER TEMPERATURES WILL
BEGIN TO WORK INTO WESTERN NEBRASKA ON WEDNESDAY...HOWEVER...COLD
TEMPERATURES WILL REMAIN AT IN THE EASTERN CWA WITH HIGHS AROUND 40
FOR KONL...AND 42 FOR KANW. READINGS WILL BE IN THE LOWER 50S ACROSS
SWRN NEBRASKA AND THE EASTERN PANHANDLE. BASED ON FCST 500 METER
WINDS...SURFACE WIND SPEEDS ARE EXPECTED TO BE WELL BELOW ADVISORY
CRITERIA WEDS AFTERNOON.
WEDNESDAY NIGHT THROUGH SUNDAY...COLD AIR WILL SLIDE
EAST WITH THE HIGH WEDNESDAY NIGHT...AND SURFACE LOW PRESSURE WILL
DEEPEN OVER EASTERN COLORADO. SRLY WINDS WILL INCREASE...ALONG WITH
TEMPERATURES AS THE ARCTIC AIR MASS SHIFTS EAST OF THE AREA. FCST
H85 TEMPS WILL INCREASE TO 8 TO 12 C THURSDAY AFTERNOON AHEAD OF A
APPG COLD FRONT. THE COMBINATION OF THE APPG COLD FRONT...SRLY
WINDS...AND RIDGING ALOFT...WILL RESULT IN HIGHS IN THE 50S TO LOWER
60S THURSDAY. AFTER ONE DAY OF WARM TEMPERATURES...MUCH COOLER
TEMPERATURES AND THE POTENTIAL FOR A POTENT WINTER STORM...WILL
BEGIN TO PUSH ACROSS SRN ROCKIES ONTO THE CENTRAL AND SRN PLAINS
FRIDAY NIGHT INTO SATURDAY. SOME TRACK DIFFERENCES EXIST BETWEEN THE
GFS AND EC MODEL RUNS THIS MORNING. THE GFS REMAINS SOUTH...WITH THE
ECMWF BEING FURTHER NORTH. BOTH SOLUTIONS PUSH COLD FRONT INTO THE
FORECAST AREA EITHER FRIDAY NIGHT OR SATURDAY DEPENDING ON MODEL
CHOICE. THE RESULTANT AIRMASS BEHIND THE FRONT WILL BE A SHALLOW SUB
FREEZING LAYER...WITH DECENT MID LEVEL ASCENT NOTED ABOVE THIS
LAYER. WOULDN`T BE SURPRISED TO SEE A MIX OF PCPN ACROSS THE NORTH
FOR FRIDAY INTO FRIDAY NIGHT. HOWEVER...GIVEN THE MODEL DIFFERENCES
WITH THE TIMING OF THE FRONT...DECIDED TO WORD PRECIPITATION MENTION
AS RAIN OR SNOW ATTM. THIS WILL CARRY OVER INTO THE WEEKEND WITH
HIGHS IN THE 30S AND LOWS IN THE 20S. ATTM...THE EXTENDED BEYOND
THURSDAY REMAINS A LOW CONFIDENCE FCST...IN PARTICULAR PRECIPITATION
TYPE...AS POOR MODEL AGREEMENT IS NOTED. NO DOUBT...WE COULD SEE
SOME PRECIPITATION NEXT WEEKEND GIVEN THE CURRENT EC AND GFS
SOLNS...AND CHANCE POPS REFLECT THAT IN THE CURRENT FCST. BASED ON
EITHER SOLUTION...WE COULD BE DEALING WITH LIGHT PRECIPITATION...OR
A SIGNIFICANT SNOW STORM (12Z ECMWF SOLUTION). WILL NEED TO MONITOR
THIS CLOSELY OVER THE NEXT FEW DAYS AS WE GRAVITATE TOWARD
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 524 PM CST SUN MAR 3 2013
A POWERFUL PACIFIC COLD FRONT...CURRENTLY MOVING THROUGH SERN
MT...WILL APPROACH KVTN AROUND 07Z-09Z. THE FRONT HAS THE
POTENTIAL TO PRODUCE STRONG WIND GUSTS AND MVFR AS IT SWEEPS THE FCST
AREA OVERNIGHT. THE HRRR MODEL INDICATES THE FRONT WILL HIT KVTN
AROUND 07Z AND PRODUCE WIND GUSTS OVER 50KT SO WE WILL BE
MONITORING THE FRONT AS IT MOVES THROUGH WRN SD THIS EVENING.
OTHERWISE VFR IS EXPECTED MONDAY. WINDS ARE EXPECTED TO INCREASE
T0 31028G42KT DURING THE LATE MORNING WEST...AND DURING THE AFTN
EAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CST /11 AM MST/ MONDAY TO MIDNIGHT CST
/11 PM MST/ MONDAY NIGHT FOR NEZ004-022>024-035-036-056-057-094.
WIND ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
NEZ005>010-025>029.
&&
$$
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1122 AM CST SAT MAR 2 2013
.AVIATION...18Z KGRI TAF. QUIET CONDITIONS ARE EXPECTED THROUGH
THE TAF PERIOD...WITH THE PRIMARY CONCERN LYING WITH FOG POTENTIAL
TONIGHT. THROUGH THE REST OF THIS AFTERNOON...SCT MID LEVEL
CLOUDS WILL LINGER ON...AND WINDS WILL REMAIN S/SWRLY WITH SPEEDS
ARND 10KTS AHEAD OF A FRONTAL BOUNDARY OVER WRN NEB/KS. SOME
MODELS/GUIDANCE SUGGEST THAT WITH THE DIMINISHING WINDS EXPECTED
OVERNIGHT THAT FOG WILL DEVELOP...AND CONTINUED THE MVFR
VISIBILITIES. THERE ARE ENOUGH DIFFERENCES IN THE MODELS TO NOT
GO ANY LOWER THAN THAT AT THIS POINT.
&&
.PREV DISCUSSION... /ISSUED 622 AM CST SAT MAR 2 2013/
SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 403 AM CST SAT MAR 2 2013
TODAY...THERE HAS BEEN SOME EARLY MORNING FOG WEST OF HIGHWAY 281
WITH PATCHY DENSE FOG AT TIMES WEST OF HIGHWAY 183. THE HRRR MODEL
LINGERS THIS FOG ALL THE WAY THROUGH THE ENTIRE MORNING AND
EXPANDS THE FOG EASTWARD IN AREA TO INCLUDE THE HIGHWAY 281
CORRIDOR. THE WIND WILL BE LIGHT...WHICH WILL MAKE IT DIFFICULT
FOR THE FOG TO DISPERSE TOO QUICKLY. HOWEVER...GIVEN THE LIMITED
EXTENT OF THE FOG THUS FAR AS OF 4 AM...BELIEVE THAT THE FOG WILL
NOT BE AS BIG OF A DEAL AS INDICATED BY THE HRRR MODEL.
THEREFORE...WILL BE CALLING FOR ANY FOG TO LIFT BY MID MORNING.
THE WIND WILL GRADUALLY INCREASE FROM THE SOUTH THIS AFTERNOON AND
WARMER AIR ALOFT WILL ALSO WORK IN FROM THE WEST AS AN UPPER RIDGE
BEGINS TO SLIDE EAST INTO THE PLAINS. THEREFORE...EXPECT A WARMER
DAY WITH HIGHS A GOOD DEAL ABOVE FREEZING DESPITE THE SNOW COVER.
HIGHS SHOULD RANGE FROM THE MID 30S ALONG HIGHWAY 81 TO THE MID 40S
WEST OF HIGHWAY 183.
SUNDAY...THIS WILL BE THE NICEST DAY OF THE WEEKEND WITH MUCH OF
THE REMAINING SNOW COVER MELTING. THE WIND WILL REMAIN SOUTHERLY
AND 850MB TEMPERATURES WILL CONTINUE TO CLIMB INTO THE 8-12C RANGE
WITH RIDGING ALOFT.
MONDAY INTO MONDAY NIGHT...A POTENT LITTLE STORM SYSTEM IS
PROJECTED TO TRACK ACROSS THE DAKOTAS AND SHOULD SEND A FAIRLY
SHARP SFC COLD FRONT THROUGH NEBRASKA. HOWEVER...MOST OF THE
PRECIPITATION/SNOW WILL BE WELL NORTH OF OUR FORECAST AREA IN
ASSOCIATION WITH THE UPPER LOW AND SHOULD TRACK SOUTHEAST INTO
MINNESOTA AND EASTERN IOWA. THE LATEST RUN OF THE 00Z ECWMF IS
EVEN FURTHER NORTH WITH THIS SYSTEM THAN PREVIOUS RUNS RESULTING
IN DECREASING POPS ACROSS OUR FORECAST AREA. MOST AREAS WILL FAIL
TO SEE MEASURABLE PRECIPITATION IF THIS NORTHERN TRACK HOLDS TRUE.
IT WILL BE BREEZY BEHIND THE COLD FRONT...BUT EXPECT THE STRONGER
WIND MAY NOT MOVE INTO OUR AREA UNTIL THE UPPER LOW PASSES FURTHER
TO OUR EAST...WHICH WOULD BE ON TUESDAY. TEMPERATURES WILL BE
COOLER ON MONDAY BEHIND THE COLD FRONT.
LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 403 AM CST SAT MAR 2 2013
ALTHOUGH THIS 4-DAY PERIOD DOES NOT APPEAR TO CONTAIN ANY TRULY HIGH
IMPACT WEATHER...AND IS OFFICIALLY PRECIP-FREE IN OUR PRODUCTS AT
LEAST FOR NOW...WILL HAVE TO KEEP AN EYE OUT FOR VARIOUS ELEMENTS
INCLUDING THE POSSIBILITY OF SOME LINGERING FLURRIES/LIGHT SNOW
TUESDAY...POTENTIALLY STRONG NORTH WINDS TUESDAY...AND POTENTIALLY
FAIRLY STRONG SOUTH WINDS BY THURSDAY.
STARTING OFF TUESDAY/TUESDAY NIGHT...UNFORTUNATELY MODEL AGREEMENT
AMONGST THE 00Z ECMWF/GFS/GEM SOLUTIONS LEAVES A BIT TO BE DESIRED.
ON A BASIC SYNOPTIC SCALE ALOFT...ALL 3 MODELS AT LEAST SHOW A
FAIRLY STOUT NORTHWEST-FLOW SHORTWAVE TROUGH DIVING SOUTHEAST FROM A
POSITION IN THE THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING...TO
THE TENNESSEE VICINITY BY WEDNESDAY MORNING. HOWEVER...GETTING MORE
INTO THE DETAILS...THE GFS/GEM TRACKS THE HEART OF THE 500MB VORT
MAX ACROSS AT LEAST EASTERN IF NOT CENTRAL PORTIONS OF NEB/KS DURING
THE DAY...WHILE THE ECMWF KEEPS THE MAIN FORCING A FEW HUNDRED MILES
FARTHER NORTHEAST OVER SOUTHERN MN/IA. CERTAINLY IF THE FARTHER
SOUTHWEST SOLUTIONS ARE CORRECT...WE MAY VERY WELL NEED SOME
FLURRIES OR MAYBE EVEN A MEASURABLE POP FOR LIGHT SNOW INTRODUCED IN
LATER FORECASTS MAINLY ACROSS THE NORTHEAST 1/2 OF THE CWA FOR
TUESDAY DAYTIME. HOWEVER...GIVEN THAT THIS IS STILL 7 PERIODS OUT
WILL HOLD OFF FOR NOW. OF LIKELY GREATER IMPORTANCE...AND WHAT ALL
OF THESE MODELS SEEM TO AGREE ON...IS THAT TUESDAY IS TRENDING
WINDIER AS THIS AFOREMENTIONED SHORTWAVE PASSES AND SURFACE PRESSURE
RISES RAMP UP IN RESPONSE TO STRONG HIGH PRESSURE NOSING IN FROM THE
NORTH. FOR NOW HAVE RAISED SUSTAINED SPEEDS GENERALLY 5-10 MPH FROM
PREVIOUS FORECAST...GETTING UP IN THE 20-25 MPH RANGE BUT STILL
SOLIDLY 5 MPH SHORT OF ADVISORY CRITERIA. THIS WILL BEAR WATCHING
HOWEVER...AND IF THESE SPEEDS PICK UP MUCH MORE A STRONG WIND
MENTION MAY SOON BE WARRANTED IN THE HAZARDOUS WEATHER OUTLOOK. BY
TUESDAY EVENING...WIND SPEEDS SHOULD SUBSIDE FAIRLY STEADILY AS THE
HIGH PRESSURE AXIS SETTLES INTO THE CENTRAL PLAINS. TEMP-WISE...MADE
ONLY SMALL TWEAKS WITH DAYTIME HIGHS SOMEWHERE IN THE 30S AND TUES
NIGHT LOWS MAINLY IN THE TEENS.
WEDNESDAY/WEDNESDAY NIGHT...THE ECMWF/GFS/GEM ARE IN FAIRLY GOOD
AGREEMENT FOR THIS TIME RANGE IN DEPICTING A BRIEF PERIOD OF
SHORTWAVE RIDGING ALOFT TRANSLATING OVER THE CENTRAL PLAINS IN
ADVANCE OF THE NEXT UPSTREAM OPEN WAVE MAKING INROADS ACROSS THE
WESTERN CONUS. THIS GIVES A RATHER HIGH CONFIDENCE IN A DRY 24
HOURS. WITH THE SURFACE RIDGE AXIS QUICKLY MOVING OFF TO THE EAST
AND HIGH PLAINS SURFACE PRESSURE FALLS COMMENCING TO OUR
EAST...WEDNESDAY SHOULD HAVE SOUTH-SOUTHEAST BREEZES AROUND 15 MPH
OR HIGHER...WITH THESE SPEEDS MAINTAINING THROUGH THE NIGHT.
DESPITE THE SOUTHERLY WIND DIRECTION...NOT SURE HOW STRONG WARMING
WILL BE GIVEN THAT COLD AIR WILL BE RE-CIRCULATED AROUND THE
DEPARTING RIDGE AXIS TO SOME EXTENT. AS A RESULT...ACTUALLY NUDGED
DOWN HIGHS A FEW DEGREES ALL AREAS...BUT STILL INTO THE 40S EXCEPT
UPPER 30S FAR NORTHEAST. WEDNESDAY NIGHT LOW TEMPS SHOULD AVERAGE
AROUND 10 DEGREES WARMER THAN TUESDAY NIGHT WITH MAINLY UPPER 20S TO
NEAR 30.
THURSDAY/THURSDAY NIGHT...CONFIDENCE STARTS TO WANE A LITTLE BIT
THAT THIS 24 HOURS WILL TRULY STAY PRECIP-FREE...AS THE
ECMWF/GFS/GEM START TO DIVERGE REGARDING HOW THE WESTERN CONUS
TROUGH IS HANDLED. WHILE THE ECMWF/GFS TRACK A LEAD MID LEVEL
SHORTWAVE MAINLY TO OUR NORTH INTO THE DAKOTAS DURING THIS
TIME...THE GEM SOLUTION TAKES THIS LEAD WAVE RIGHT INTO WESTERN
NEB/KS BY THURS EVENING...SUGGESTING SOME POSSIBLE RAIN SHOWER
POTENTIAL. FOR NOW WILL MAINTAIN THE DRY COURSE. AT THE
SURFACE...SOUTHERLY WINDS WILL LIKELY RAMP UP ANOTHER NOTCH IN A
TIGHTENED PRESSURE GRADIENT...AND ALTHOUGH THE OFFICIAL GRIDS ONLY
DEPICT AROUND 20 MPH SUSTAINED SPEEDS AT THIS TIME...ACTUAL SPEEDS
COULD ULTIMATELY PROVE TO BE AT LEAST 5-10 MPH HIGHER IF TRENDS
HOLD. TEMP-WISE...THURSDAY STILL LOOKS LIKE THE LIKELY CANDIDATE FOR
THE WARMEST DAY OF THE WEEK...ALTHOUGH EVEN THE DEGREE OF WARMING
ABOVE THE SURFACE AT 850MB IS NOT SHOWING GREAT MODEL AGREEMENT.
GIVEN THIS UNCERTAINTY...OPTED TO MAKE NO CHANGES WHATSOEVER TO
PREVIOUS HIGHS...PUSHING THE ENTIRE CWA SOMEWHERE INTO THE
50S...WITH FAR WESTERN COUNTIES MAYBE CRACKING 60. PER THE
ECMWF/GFS...A COLD FRONT THEN STARTS SAGGING SOUTHWARD INTO THE CWA
THURSDAY NIGHT.
FRIDAY...THE GENERAL THEME PER THE ECMWF/GFS IS THAT BROAD SOUTHWEST
FLOW ALOFT PERSISTS OVER THE CENTRAL PLAINS...DOWNSTREAM FROM A
LARGE TROUGH/CLOSED LOW DIGGING INTO THE SOUTHERN CA/AZ REGION.
THERE ARE SUGGESTIONS THAT SOME RAIN SHOWERS COULD BREAK OUT MAINLY
LATE IN THE DAY IN PARTS OF THE CWA PER THE ECMWF...BUT WILL HOLD
POPS IN SILENT TERRITORY FOR NOW...WITH POTENTIALLY MUCH BETTER
PRECIP CHANCES ENTERING THE PICTURE JUST BEYOND THE OFFICIAL
FORECAST PERIODS FOR FRI NIGHT-SATURDAY. HOWEVER...EVEN THIS WEEKEND
PRECIP CHANCE IS IN QUESTION REGARDING WHETHER IT SQUARELY AFFECTS
THE CWA...OR TRENDS MORE TO OUR SOUTH. TEMP-WISE...FRIDAY CERTAINLY
LOOKS COOLER THAN THURSDAY WITH STEADY NORTHEAST WINDS IN PLACE
BEHIND A COLD FRONT...JUST A MATTER OF HOW MUCH COOLER. FOR NOW WILL
RUN WITH A RANGE FROM MID 40S NORTH TO LOW 50S SOUTH...WHICH IS JUST
A TOUCH COOLER THAN PREVIOUS FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CST SAT MAR 2 2013
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 403 AM CST SAT MAR 2 2013
TODAY...THERE HAS BEEN SOME EARLY MORNING FOG WEST OF HIGHWAY 281
WITH PATCHY DENSE FOG AT TIMES WEST OF HIGHWAY 183. THE HRRR MODEL
LINGERS THIS FOG ALL THE WAY THROUGH THE ENTIRE MORNING AND
EXPANDS THE FOG EASTWARD IN AREA TO INCLUDE THE HIGHWAY 281
CORRIDOR. THE WIND WILL BE LIGHT...WHICH WILL MAKE IT DIFFICULT
FOR THE FOG TO DISPERSE TOO QUICKLY. HOWEVER...GIVEN THE LIMITED
EXTENT OF THE FOG THUS FAR AS OF 4 AM...BELIEVE THAT THE FOG WILL
NOT BE AS BIG OF A DEAL AS INDICATED BY THE HRRR MODEL.
THEREFORE...WILL BE CALLING FOR ANY FOG TO LIFT BY MID MORNING.
THE WIND WILL GRADUALLY INCREASE FROM THE SOUTH THIS AFTERNOON AND
WARMER AIR ALOFT WILL ALSO WORK IN FROM THE WEST AS AN UPPER RIDGE
BEGINS TO SLIDE EAST INTO THE PLAINS. THEREFORE...EXPECT A WARMER
DAY WITH HIGHS A GOOD DEAL ABOVE FREEZING DESPITE THE SNOW COVER.
HIGHS SHOULD RANGE FROM THE MID 30S ALONG HIGHWAY 81 TO THE MID 40S
WEST OF HIGHWAY 183.
SUNDAY...THIS WILL BE THE NICEST DAY OF THE WEEKEND WITH MUCH OF
THE REMAINING SNOW COVER MELTING. THE WIND WILL REMAIN SOUTHERLY
AND 850MB TEMPERATURES WILL CONTINUE TO CLIMB INTO THE 8-12C RANGE
WITH RIDGING ALOFT.
MONDAY INTO MONDAY NIGHT...A POTENT LITTLE STORM SYSTEM IS
PROJECTED TO TRACK ACROSS THE DAKOTAS AND SHOULD SEND A FAIRLY
SHARP SFC COLD FRONT THROUGH NEBRASKA. HOWEVER...MOST OF THE
PRECIPITATION/SNOW WILL BE WELL NORTH OF OUR FORECAST AREA IN
ASSOCIATION WITH THE UPPER LOW AND SHOULD TRACK SOUTHEAST INTO
MINNESOTA AND EASTERN IOWA. THE LATEST RUN OF THE 00Z ECWMF IS
EVEN FURTHER NORTH WITH THIS SYSTEM THAN PREVIOUS RUNS RESULTING
IN DECREASING POPS ACROSS OUR FORECAST AREA. MOST AREAS WILL FAIL
TO SEE MEASURABLE PRECIPITATION IF THIS NORTHERN TRACK HOLDS TRUE.
IT WILL BE BREEZY BEHIND THE COLD FRONT...BUT EXPECT THE STRONGER
WIND MAY NOT MOVE INTO OUR AREA UNTIL THE UPPER LOW PASSES FURTHER
TO OUR EAST...WHICH WOULD BE ON TUESDAY. TEMPERATURES WILL BE
COOLER ON MONDAY BEHIND THE COLD FRONT.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 403 AM CST SAT MAR 2 2013
ALTHOUGH THIS 4-DAY PERIOD DOES NOT APPEAR TO CONTAIN ANY TRULY HIGH
IMPACT WEATHER...AND IS OFFICIALLY PRECIP-FREE IN OUR PRODUCTS AT
LEAST FOR NOW...WILL HAVE TO KEEP AN EYE OUT FOR VARIOUS ELEMENTS
INCLUDING THE POSSIBILITY OF SOME LINGERING FLURRIES/LIGHT SNOW
TUESDAY...POTENTIALLY STRONG NORTH WINDS TUESDAY...AND POTENTIALLY
FAIRLY STRONG SOUTH WINDS BY THURSDAY.
STARTING OFF TUESDAY/TUESDAY NIGHT...UNFORTUNATELY MODEL AGREEMENT
AMONGST THE 00Z ECMWF/GFS/GEM SOLUTIONS LEAVES A BIT TO BE DESIRED.
ON A BASIC SYNOPTIC SCALE ALOFT...ALL 3 MODELS AT LEAST SHOW A
FAIRLY STOUT NORTHWEST-FLOW SHORTWAVE TROUGH DIVING SOUTHEAST FROM A
POSITION IN THE THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING...TO
THE TENNESSEE VICINITY BY WEDNESDAY MORNING. HOWEVER...GETTING MORE
INTO THE DETAILS...THE GFS/GEM TRACKS THE HEART OF THE 500MB VORT
MAX ACROSS AT LEAST EASTERN IF NOT CENTRAL PORTIONS OF NEB/KS DURING
THE DAY...WHILE THE ECMWF KEEPS THE MAIN FORCING A FEW HUNDRED MILES
FARTHER NORTHEAST OVER SOUTHERN MN/IA. CERTAINLY IF THE FARTHER
SOUTHWEST SOLUTIONS ARE CORRECT...WE MAY VERY WELL NEED SOME
FLURRIES OR MAYBE EVEN A MEASURABLE POP FOR LIGHT SNOW INTRODUCED IN
LATER FORECASTS MAINLY ACROSS THE NORTHEAST 1/2 OF THE CWA FOR
TUESDAY DAYTIME. HOWEVER...GIVEN THAT THIS IS STILL 7 PERIODS OUT
WILL HOLD OFF FOR NOW. OF LIKELY GREATER IMPORTANCE...AND WHAT ALL
OF THESE MODELS SEEM TO AGREE ON...IS THAT TUESDAY IS TRENDING
WINDIER AS THIS AFOREMENTIONED SHORTWAVE PASSES AND SURFACE PRESSURE
RISES RAMP UP IN RESPONSE TO STRONG HIGH PRESSURE NOSING IN FROM THE
NORTH. FOR NOW HAVE RAISED SUSTAINED SPEEDS GENERALLY 5-10 MPH FROM
PREVIOUS FORECAST...GETTING UP IN THE 20-25 MPH RANGE BUT STILL
SOLIDLY 5 MPH SHORT OF ADVISORY CRITERIA. THIS WILL BEAR WATCHING
HOWEVER...AND IF THESE SPEEDS PICK UP MUCH MORE A STRONG WIND
MENTION MAY SOON BE WARRANTED IN THE HAZARDOUS WEATHER OUTLOOK. BY
TUESDAY EVENING...WIND SPEEDS SHOULD SUBSIDE FAIRLY STEADILY AS THE
HIGH PRESSURE AXIS SETTLES INTO THE CENTRAL PLAINS. TEMP-WISE...MADE
ONLY SMALL TWEAKS WITH DAYTIME HIGHS SOMEWHERE IN THE 30S AND TUES
NIGHT LOWS MAINLY IN THE TEENS.
WEDNESDAY/WEDNESDAY NIGHT...THE ECMWF/GFS/GEM ARE IN FAIRLY GOOD
AGREEMENT FOR THIS TIME RANGE IN DEPICTING A BRIEF PERIOD OF
SHORTWAVE RIDGING ALOFT TRANSLATING OVER THE CENTRAL PLAINS IN
ADVANCE OF THE NEXT UPSTREAM OPEN WAVE MAKING INROADS ACROSS THE
WESTERN CONUS. THIS GIVES A RATHER HIGH CONFIDENCE IN A DRY 24
HOURS. WITH THE SURFACE RIDGE AXIS QUICKLY MOVING OFF TO THE EAST
AND HIGH PLAINS SURFACE PRESSURE FALLS COMMENCING TO OUR
EAST...WEDNESDAY SHOULD HAVE SOUTH-SOUTHEAST BREEZES AROUND 15 MPH
OR HIGHER...WITH THESE SPEEDS MAINTAINING THROUGH THE NIGHT.
DESPITE THE SOUTHERLY WIND DIRECTION...NOT SURE HOW STRONG WARMING
WILL BE GIVEN THAT COLD AIR WILL BE RE-CIRCULATED AROUND THE
DEPARTING RIDGE AXIS TO SOME EXTENT. AS A RESULT...ACTUALLY NUDGED
DOWN HIGHS A FEW DEGREES ALL AREAS...BUT STILL INTO THE 40S EXCEPT
UPPER 30S FAR NORTHEAST. WEDNESDAY NIGHT LOW TEMPS SHOULD AVERAGE
AROUND 10 DEGREES WARMER THAN TUESDAY NIGHT WITH MAINLY UPPER 20S TO
NEAR 30.
THURSDAY/THURSDAY NIGHT...CONFIDENCE STARTS TO WANE A LITTLE BIT
THAT THIS 24 HOURS WILL TRULY STAY PRECIP-FREE...AS THE
ECMWF/GFS/GEM START TO DIVERGE REGARDING HOW THE WESTERN CONUS
TROUGH IS HANDLED. WHILE THE ECMWF/GFS TRACK A LEAD MID LEVEL
SHORTWAVE MAINLY TO OUR NORTH INTO THE DAKOTAS DURING THIS
TIME...THE GEM SOLUTION TAKES THIS LEAD WAVE RIGHT INTO WESTERN
NEB/KS BY THURS EVENING...SUGGESTING SOME POSSIBLE RAIN SHOWER
POTENTIAL. FOR NOW WILL MAINTAIN THE DRY COURSE. AT THE
SURFACE...SOUTHERLY WINDS WILL LIKELY RAMP UP ANOTHER NOTCH IN A
TIGHTENED PRESSURE GRADIENT...AND ALTHOUGH THE OFFICIAL GRIDS ONLY
DEPICT AROUND 20 MPH SUSTAINED SPEEDS AT THIS TIME...ACTUAL SPEEDS
COULD ULTIMATELY PROVE TO BE AT LEAST 5-10 MPH HIGHER IF TRENDS
HOLD. TEMP-WISE...THURSDAY STILL LOOKS LIKE THE LIKELY CANDIDATE FOR
THE WARMEST DAY OF THE WEEK...ALTHOUGH EVEN THE DEGREE OF WARMING
ABOVE THE SURFACE AT 850MB IS NOT SHOWING GREAT MODEL AGREEMENT.
GIVEN THIS UNCERTAINTY...OPTED TO MAKE NO CHANGES WHATSOEVER TO
PREVIOUS HIGHS...PUSHING THE ENTIRE CWA SOMEWHERE INTO THE
50S...WITH FAR WESTERN COUNTIES MAYBE CRACKING 60. PER THE
ECMWF/GFS...A COLD FRONT THEN STARTS SAGGING SOUTHWARD INTO THE CWA
THURSDAY NIGHT.
FRIDAY...THE GENERAL THEME PER THE ECMWF/GFS IS THAT BROAD SOUTHWEST
FLOW ALOFT PERSISTS OVER THE CENTRAL PLAINS...DOWNSTREAM FROM A
LARGE TROUGH/CLOSED LOW DIGGING INTO THE SOUTHERN CA/AZ REGION.
THERE ARE SUGGESTIONS THAT SOME RAIN SHOWERS COULD BREAK OUT MAINLY
LATE IN THE DAY IN PARTS OF THE CWA PER THE ECMWF...BUT WILL HOLD
POPS IN SILENT TERRITORY FOR NOW...WITH POTENTIALLY MUCH BETTER
PRECIP CHANCES ENTERING THE PICTURE JUST BEYOND THE OFFICIAL
FORECAST PERIODS FOR FRI NIGHT-SATURDAY. HOWEVER...EVEN THIS WEEKEND
PRECIP CHANCE IS IN QUESTION REGARDING WHETHER IT SQUARELY AFFECTS
THE CWA...OR TRENDS MORE TO OUR SOUTH. TEMP-WISE...FRIDAY CERTAINLY
LOOKS COOLER THAN THURSDAY WITH STEADY NORTHEAST WINDS IN PLACE
BEHIND A COLD FRONT...JUST A MATTER OF HOW MUCH COOLER. FOR NOW WILL
RUN WITH A RANGE FROM MID 40S NORTH TO LOW 50S SOUTH...WHICH IS JUST
A TOUCH COOLER THAN PREVIOUS FORECAST.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z SUNDAY MORNING)
ISSUED AT 604 AM CST SAT MAR 2 2013
ALTHOUGH THE MAJORITY OF THE PERIOD IS EXPECTED TO FEATURE VFR
CONDITIONS...CONFIDENCE ESPECIALLY REGARDING VISIBILITY TRENDS IS
NOT OVERLY HIGH. STARTING OUT EARLY THIS MORNING...HAVE BEEN WAITING
ALL NIGHT FOR THE POSSIBLE ONSET OF FOG THAT HAS NOT SET IN...AND
NOW THAT INCREASING MID LEVEL CLOUDS ARE MOVING IN...FOG IS
SEEMING LESS AND LESS LIKELY. HOWEVER...JUST TO HINT AT THE
POSSIBILITY OF LIMITED FOG DEVELOPMENT HAVE INDICATED SOME 6SM BR
VISIBILITY THROUGH 16Z. OTHERWISE...EXPECT PLENTY OF VFR MID-
CLOUDS DURING THE DAYTIME HOURS...AS BREEZES TOP OUT AROUND 10KT
FROM THE SOUTH-SOUTHWEST. A FEW SNOW FLURRIES ARE NOT EVEN OUT OF
THE QUESTION THIS MORNING...BUT THIS DOES NOT SEEM WORTHY OF A
MENTION. TURNING TO SATURDAY NIGHT...CONFIDENCE IN VISIBILITY
TRENDS AGAIN LOWERS CONSIDERABLY...AS VARIOUS MODEL/GUIDANCE
SOLUTIONS OFFER DIFFERING OPINIONS ON FOG DEVELOPMENT. ON ONE
HAND...AT LEAST LIMITED SNOW MELT TODAY WOULD FAVOR A MORE ROBUST
ONSET OF FOG...BUT A LIGHT BUT STEADY SOUTHWESTERLY BREEZE IS
NORMALLY NOT CONDUCIVE FOR MAJOR FOG ISSUES. FOR THE TIME
BEING...WILL INTRODUCE PREVAILING MVFR VSBY AT 04Z AND KEEP IT
GOING THROUGH THE END OF THE PERIOD...BUT PLEASE ALLOW FOR PLENTY
OF WIGGLE ROOM ON BOTH THE OPTIMISTIC AND PESSIMISTIC SIDE OF THIS
VALUE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CST SAT MAR 2 2013
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 403 AM CST SAT MAR 2 2013
TODAY...THERE HAS BEEN SOME EARLY MORNING FOG WEST OF HIGHWAY 281
WITH PATCHY DENSE FOG AT TIMES WEST OF HIGHWAY 183. THE HRRR MODEL
LINGERS THIS FOG ALL THE WAY THROUGH THE ENTIRE MORNING AND
EXPANDS THE FOG EASTWARD IN AREA TO INCLUDE THE HIGHWAY 281
CORRIDOR. THE WIND WILL BE LIGHT...WHICH WILL MAKE IT DIFFICULT
FOR THE FOG TO DISPERSE TOO QUICKLY. HOWEVER...GIVEN THE LIMITED
EXTENT OF THE FOG THUS FAR AS OF 4 AM...BELIEVE THAT THE FOG WILL
NOT BE AS BIG OF A DEAL AS INDICATED BY THE HRRR MODEL.
THEREFORE...WILL BE CALLING FOR ANY FOG TO LIFT BY MID MORNING.
THE WIND WILL GRADUALLY INCREASE FROM THE SOUTH THIS AFTERNOON AND
WARMER AIR ALOFT WILL ALSO WORK IN FROM THE WEST AS AN UPPER RIDGE
BEGINS TO SLIDE EAST INTO THE PLAINS. THEREFORE...EXPECT A WARMER
DAY WITH HIGHS A GOOD DEAL ABOVE FREEZING DESPITE THE SNOW COVER.
HIGHS SHOULD RANGE FROM THE MID 30S ALONG HIGHWAY 81 TO THE MID 40S
WEST OF HIGHWAY 183.
SUNDAY...THIS WILL BE THE NICEST DAY OF THE WEEKEND WITH MUCH OF
THE REMAINING SNOW COVER MELTING. THE WIND WILL REMAIN SOUTHERLY
AND 850MB TEMPERATURES WILL CONTINUE TO CLIMB INTO THE 8-12C RANGE
WITH RIDGING ALOFT.
MONDAY INTO MONDAY NIGHT...A POTENT LITTLE STORM SYSTEM IS
PROJECTED TO TRACK ACROSS THE DAKOTAS AND SHOULD SEND A FAIRLY
SHARP SFC COLD FRONT THROUGH NEBRASKA. HOWEVER...MOST OF THE
PRECIPITATION/SNOW WILL BE WELL NORTH OF OUR FORECAST AREA IN
ASSOCIATION WITH THE UPPER LOW AND SHOULD TRACK SOUTHEAST INTO
MINNESOTA AND EASTERN IOWA. THE LATEST RUN OF THE 00Z ECWMF IS
EVEN FURTHER NORTH WITH THIS SYSTEM THAN PREVIOUS RUNS RESULTING
IN DECREASING POPS ACROSS OUR FORECAST AREA. MOST AREAS WILL FAIL
TO SEE MEASURABLE PRECIPITATION IF THIS NORTHERN TRACK HOLDS TRUE.
IT WILL BE BREEZY BEHIND THE COLD FRONT...BUT EXPECT THE STRONGER
WIND MAY NOT MOVE INTO OUR AREA UNTIL THE UPPER LOW PASSES FURTHER
TO OUR EAST...WHICH WOULD BE ON TUESDAY. TEMPERATURES WILL BE
COOLER ON MONDAY BEHIND THE COLD FRONT.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 403 AM CST SAT MAR 2 2013
ALTHOUGH THIS 4-DAY PERIOD DOES
NOT LOOK TO CONTAIN ANY TRULY HIGH IMPACT WEATHER...AND IS
OFFICIALLY PRECIP-FREE IN OUR PRODUCTS AT LEAST FOR NOW...WILL HAVE TO
KEEP AN EYE OUT FOR VARIOUS ELEMENTS INCLUDING THE POSSIBILITY OF SOME
LINGERING FLURRIES/LIGHT SNOW TUESDAY...POTENTIALLY STRONG
NORTH WINDS TUESDAY...AND POTENTIALLY FAIRLY STRONG SOUTH WINDS BY
THURSDAY.
STARTING OFF TUESDAY/TUESDAY NIGHT...UNFORTUNATELY MODEL AGREEMENT
AMONGST THE 00Z ECMWF/GFS/GEM SOLUTIONS LEAVES A BIT TO BE DESIRED.
ON A BASIC SYNOPTIC SCALE ALOFT...ALL 3 MODELS AT LEAST SHOW A
FAIRLY STOUT NORTHWEST-FLOW SHORTWAVE TROUGH DIVING SOUTHEAST FROM A
POSITION IN THE THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING...TO
THE TENNESSEE VICINITY BY WEDNESDAY MORNING. HOWEVER...GETTING MORE
INTO THE DETAILS...THE GFS/GEM TRACKS THE HEART OF THE 500MB VORT
MAX ACROSS AT LEAST EASTERN IF NOT CENTRAL PORTIONS OF NEB/KS DURING
THE DAY...WHILE THE ECMWF KEEPS THE MAIN FORCING A FEW HUNDRED MILES
FARTHER NORTHEAST OVER SOUTHERN MN/IA. CERTAINLY IF THE FARTHER
SOUTHWEST SOLUTIONS ARE CORRECT...WE MAY VERY WELL NEED SOME
FLURRIES OR MAYBE EVEN A MEASURABLE POP FOR LIGHT SNOW INTRODUCED IN
LATER FORECASTS MAINLY ACROSS THE NORTHEAST 1/2 OF THE CWA FOR
TUESDAY DAYTIME. HOWEVER...GIVEN THAT THIS IS STILL 7 PERIODS OUT
WILL HOLD OFF FOR NOW. OF LIKELY GREATER IMPORTANCE...AND WHAT ALL
OF THESE MODELS SEEM TO AGREE ON...IS THAT TUESDAY IS TRENDING
WINDIER AS THIS AFOREMENTIONED SHORTWAVE PASSES AND SURFACE PRESSURE
RISES RAMP UP IN RESPONSE TO STRONG HIGH PRESSURE NOSING IN FROM THE
NORTH. FOR NOW HAVE RAISED SUSTAINED SPEEDS GENERALLY 5-10 MPH FROM
PREVIOUS FORECAST...GETTING UP IN THE 20-25 MPH RANGE BUT STILL
SOLIDLY 5 MPH SHORT OF ADVISORY CRITERIA. THIS WILL BEAR WATCHING
HOWEVER...AND IF THESE SPEEDS PICK UP MUCH MORE A STRONG WIND
MENTION MAY SOON BE WARRANTED IN THE HAZARDOUS WEATHER OUTLOOK. BY
TUESDAY EVENING...WIND SPEEDS SHOULD SUBSIDE FAIRLY STEADILY AS THE
HIGH PRESSURE AXIS SETTLES INTO THE CENTRAL PLAINS. TEMP-WISE...MADE
ONLY SMALL TWEAKS WITH DAYTIME HIGHS SOMEWHERE IN THE 30S AND TUES
NIGHT LOWS MAINLY IN THE TEENS.
WEDNESDAY/WEDNESDAY NIGHT...THE ECMWF/GFS/GEM ARE IN FAIRLY GOOD
AGREEMENT FOR THIS TIME RANGE IN DEPICTING A BRIEF PERIOD OF
SHORTWAVE RIDGING ALOFT TRANSLATING OVER THE CENTRAL PLAINS IN
ADVANCE OF THE NEXT UPSTREAM OPEN WAVE MAKING INROADS ACROSS THE
WESTERN CONUS. THIS GIVES A RATHER HIGH CONFIDENCE IN A DRY 24
HOURS. WITH THE SURFACE RIDGE AXIS QUICKLY MOVING OFF TO THE EAST
AND HIGH PLAINS SURFACE PRESSURE FALLS COMMENCING TO OUR
EAST...WEDNESDAY SHOULD HAVE SOUTH-SOUTHEAST BREEZES AROUND 15 MPH
OR HIGHER...WITH THESE SPEEDS MAINTAINING THROUGH THE NIGHT.
DESPITE THE SOUTHERLY WIND DIRECTION...NOT SURE HOW STRONG WARMING
WILL BE GIVEN THAT COLD AIR WILL BE RE-CIRCULATED AROUND THE
DEPARTING RIDGE AXIS TO SOME EXTENT. AS A RESULT...ACTUALLY NUDGED
DOWN HIGHS A FEW DEGREES ALL AREAS...BUT STILL INTO THE 40S EXCEPT
UPPER 30S FAR NORTHEAST. WEDNESDAY NIGHT LOW TEMPS SHOULD AVERAGE
AROUND 10 DEGREES WARMER THAN TUESDAY NIGHT WITH MAINLY UPPER 20S TO
NEAR 30.
THURSDAY/THURSDAY NIGHT...CONFIDENCE STARTS TO WANE A LITTLE BIT
THAT THIS 24 HOURS WILL TRULY STAY PRECIP-FREE...AS THE
ECMWF/GFS/GEM START TO DIVERGE REGARDING HOW THE WESTERN CONUS
TROUGH IS HANDLED. WHILE THE ECMWF/GFS TRACK A LEAD MID LEVEL
SHORTWAVE MAINLY TO OUR NORTH INTO THE DAKOTAS DURING THIS
TIME...THE GEM SOLUTION TAKES THIS LEAD WAVE RIGHT INTO WESTERN
NEB/KS BY THURS EVENING...SUGGESTING SOME POSSIBLE RAIN SHOWER
POTENTIAL. FOR NOW WILL MAINTAIN THE DRY COURSE. AT THE
SURFACE...SOUTHERLY WINDS WILL LIKELY RAMP UP ANOTHER NOTCH IN A
TIGHTENED PRESSURE GRADIENT...AND ALTHOUGH THE OFFICIAL GRIDS ONLY
DEPICT AROUND 20 MPH SUSTAINED SPEEDS AT THIS TIME...ACTUAL SPEEDS
COULD ULTIMATELY PROVE TO BE AT LEAST 5-10 MPH HIGHER IF TRENDS
HOLD. TEMP-WISE...THURSDAY STILL LOOKS LIKE THE LIKELY CANDIDATE FOR
THE WARMEST DAY OF THE WEEK...ALTHOUGH EVEN THE DEGREE OF WARMING
ABOVE THE SURFACE AT 850MB IS NOT SHOWING GREAT MODEL AGREEMENT.
GIVEN THIS UNCERTAINTY...OPTED TO MAKE NO CHANGES WHATSOEVER TO
PREVIOUS HIGHS...PUSHING THE ENTIRE CWA SOMEWHERE INTO THE
50S...WITH FAR WESTERN COUNTIES MAYBE CRACKING 60. PER THE
ECMWF/GFS...A COLD FRONT THEN STARTS SAGGING SOUTHWARD INTO THE CWA
THURSDAY NIGHT.
FRIDAY...THE GENERAL THEME PER THE ECMWF/GFS IS THAT BROAD SOUTHWEST
FLOW ALOFT PERSISTS OVER THE CENTRAL PLAINS...DOWNSTREAM FROM A
LARGE TROUGH/CLOSED LOW DIGGING INTO THE SOUTHERN CA/AZ REGION.
THERE ARE SUGGESTIONS THAT SOME RAIN SHOWERS COULD BREAK OUT MAINLY
LATE IN THE DAY IN PARTS OF THE CWA PER THE ECMWF...BUT WILL HOLD
POPS IN SILENT TERRITORY FOR NOW...WITH POTENTIALLY MUCH BETTER
PRECIP CHANCES ENTERING THE PICTURE JUST BEYOND THE OFFICIAL
FORECAST PERIODS FOR FRI NIGHT-SATURDAY. HOWEVER...EVEN THIS WEEKEND
PRECIP CHANCE IS IN QUESTION REGARDING WHETHER IT SQUARELY AFFECTS
THE CWA...OR TRENDS MORE TO OUR SOUTH. TEMP-WISE...FRIDAY CERTAINLY
LOOKS COOLER THAN THURSDAY WITH STEADY NORTHEAST WINDS IN PLACE
BEHIND A COLD FRONT...JUST A MATTER OF HOW MUCH COOLER. FOR NOW WILL
RUN WITH A RANGE FROM MID 40S NORTH TO LOW 50S SOUTH...WHICH IS JUST
A TOUCH COOLER THAN PREVIOUS FORECAST.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1216 AM CST SAT MAR 2 2013
ALTHOUGH EXPECT PREVAILING VFR CONDITIONS THROUGH THE MAJORITY OF
THE PERIOD...CONFIDENCE ESPECIALLY REGARDING VISIBILITY TRENDS
OVER THE NEXT 6-9 HOURS IS ADMITTEDLY SHAKY. AT LEAST SO FAR
TONIGHT...EARLIER INDICATIONS OF FAIRLY WIDESPREAD IFR TO LIFR
VISIBILITY/CEILING IN FOG HAS NOT COME TO FRUITION...AND CONSENSUS
OF LATEST MODELS SUGGESTS THAT KGRI MAY REMAIN JUST FAR ENOUGH
EAST TO AVOID A MAJOR DEGRADATION IN CONDITIONS. THAT BEING
SAID...GIVEN GENERALLY LIGHT/VARIABLE BREEZES WILL AT LEAST
MAINTAIN SEVERAL HOURS OF MVFR VISIBILITY POTENTIAL...AND AMEND
SHORT TERM TRENDS AS NEEDED. ASSUMING MAJOR FOG PROBLEMS DO NOT
ARISE...EXPECT ANY CEILINGS TO REMAIN VFR THROUGH THE
PERIOD...ALTHOUGH A BROKEN VFR DECK BELOW 10 THOUSAND FEET IS
POSSIBLE FOR PART OF THE DAY. ALTHOUGH SOME MODELS ARE ALREADY
INDICATING ADDITIONAL POTENTIAL FOR FOG TOWARD THE END OF THE
PERIOD MAINLY AFTER 03Z SATURDAY EVENING...CONFIDENCE IS NOT HIGH
IN THIS SCENARIO GIVEN SHAKY MODEL PERFORMANCE IN THE
NEAR-TERM...SO WILL DEFER TO LATER FORECASTS TO POSSIBLY INSERT
SATURDAY NIGHT FOG. SURFACE WINDS WILL NOT BE MUCH OF AN ISSUE
DURING THE PERIOD...WITH SOUTH-SOUTHWEST SPEEDS ONLY TOPPING OUT
AROUND 10KT DURING THE AFTERNOON INTO SATURDAY EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1216 AM CST SAT MAR 2 2013
.UPDATE...
ISSUED AT 836 PM CST
A FAIRLY SHARP REDUCTION IN SKY COVER...ESPECIALLY
THROUGH MIDNIGHT. 11-3.9 MICRON SATELLITE IMAGERY REVEALS NEARLY
CLOUD- FREE SKIES OVER MOST OF THE CWA AT THIS HOUR...WITH A
FAIRLY SOLID LOW STRATUS DECK HOLDING JUST OFF TO OUR EAST...AND A
FAIR AMOUNT OF MID-HIGH LEVEL CLOUDS STILL FOCUSED OVER WESTERN
NEBRASKA...ALTHOUGH THESE WILL GRADUALLY BE INVADING THE CWA AS
THE NIGHT WEARS ON. THE JURY IS STILL OUT ON THE FINE DETAILS
REGARDING THE TIMING AND SEVERITY OF FOG TONIGHT...BUT DESPITE
MODELS SUCH AS THE 01Z RAP LARGELY DOWNPLAYING WIDESPREAD
VISIBILITY RESTRICTIONS...HAVE MADE NO CHANGES TO THE PREVIOUS
FORECAST AS THE SYNOPTIC SETUP OF CLEAR SKIES/LIGHT AND VARIABLE
BREEZES CERTAINLY IS SUPPORTIVE OF SOME DEGREE OF FOG. HAVE ALSO
MADE NO CHANGES TO LOW TEMPS...WITH MOST OF THE CWA STILL ON TRACK
TO BOTTOM OUT SOMEWHERE BETWEEN 13-19 DEGREES.
&&
.SHORT TERM...TONIGHT AND TOMORROW. MAIN FORECAST CONCERNS LIE
WITH FOG POTENTIAL TONIGHT AND TEMPERATURES TOMORROW.
SAW A FEW FLURRIES AFFECT PRIMARILY THE WRN AND ERN FRINGES OF THE
CWA EARLIER THIS MORNING...BUT THE AFTERNOON HAS BEEN QUIET. THE
LOW LEVEL STRATUS HAS REMAINED STUBBORN FOR MOST OF THE AREA...BUT
THERE ARE PEAKS OF SUN OUT THERE. AT THE SURFACE...A RIDGE OF HIGH
PRESSURE EXTENDS FROM CENTRAL CANADA DOWN TO THE SRN
PLAINS...KEEPING WINDS NORTH/NORTHWESTERLY...AND GUSTY AT
TIMES...ESP IN AREAS THAT HAVE BEEN ABLE TO SEE A BIT OF SUN.
LOOKING TO THIS EVENING/OVERNIGHT...DRY CONDITIONS WILL CONTINUE
WITH SHARP UPPER LEVEL NORTHWESTERLY FLOW IN PLACE. EXPECTING CLOUD
COVER TO BE VARIABLE...AND AM INSERTING A FOG MENTION INTO THE
FORECAST. MODELS ARE IN GOOD AGREEMENT SHOWING THE SFC RIDGE AXIS
SLIDING EAST INTO AND THROUGH THE CWA OVERNIGHT...DROPPING WINDS
DOWN TO LIGHT/VARIABLE. EXPECTING FOG TO DEVELOP LATE THIS EVENING
AS TEMPERATURES COOL AND WINDS FALL OFF...WHICH SHOULD LINGER INTO
THE MID MORNING HOURS ON SATURDAY. OVERNIGHT LOWS LOOKING TO FALL
INTO THE MID/UPPER TEENS.
INTO TOMORROW...DRY CONDITIONS CONTINUE...WITH MODELS IN GOOD
AGREEMENT SHOWING THE UPPER LEVEL RIDGE IN PLACE OVER THE ROCKIES
GRADUALLY SLIDING TO THE EAST. AS THE SFC RIDGE AXIS CONTINUES TO
SLIDE EAST...A TROUGH OF LOW PRESSURE DEVELOPS ALONG THE HIGH
PLAINS...BRINGING A MORE SOUTHWEST TO WESTERLY COMPONENT TO THE
WINDS...THOUGH WIND SPEEDS LOOK TO ONLY TOP OUT ARND 10 MPH.
WARMER AIR ALOFT STARTS TO BUILD IN FROM THE WEST...BUT MODEL
SOUNDINGS SHOWING THINGS NOT MIXING OVERLY WELL...SO IT WILL BE
TOUGH TO FULLY TAP INTO THAT WARMER AIR. AS A RESULT WAS HESITANT
TO RAISE FORECAST HIGHS...BUT IT SHOULD STILL BE WARMER THAN
TODAY...ESP IN THE WEST. CURRENT FORECAST CALLS FOR MID 30S IN THE
EAST TO THE LOWER/MID 40S IN THE WEST.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. BEGINNING SATURDAY
NIGHT...AN UPPER LEVEL RIDGE OF HIGH PRESSURE OVER THE ROCKIES
WILL BEGIN TO BREAK DOWN/SHIFT EAST AS AN UPSTREAM TROUGH
TRANSLATES SOUTHEAST FM BRITISH COLUMBIA. A MILD AIRMASS WILL
EXPAND EASTWARD ONTO THE CENTRAL PLAINS BY SUNDAY WITH H85 TEMPS
CLIMBING TO NEAR 10C. FORECAST SOUNDING HOWEVER INDICATE VERY
LITTLE MIXING...AND ALTHOUGH WE ARE LOOKING AT A WARMER DAY WITH
THE WARM AIRMASS IN PLACE AHEAD OF AN APPROACHING COLD
FRONT...WILL KEEP TEMPS IN THE UPPER 40S/MID 50S DUE TO LACK OF
GOOD MIXING. WILL NEED TO MONITOR OUR EASTERN ZONES FOR LINGERING
LOW CLOUD COVER AS WELL...MORE SO INDICATED BY GFS...AS LOW CLOUDS
WOULD IMPACT TEMPS.
SUNDAY NIGHT...THE UPPER TROUGH TRANSLATES INTO THE WESTERN
DAKOTAS WITH THE ASSOCIATED COLD FRONTAL BOUNDARY SWEEPING
SOUTHEAST OVERNIGHT. GOOD MID LEVEL FRONTOGENESIS IS PROGGED
BETWEEN H85 AND H7 AFTER 06Z...AND WOULD NOT BE SURPRISED TO SEE
SOME SPRINKLES/BRIEF SHOWER. FORECAST SOUNDINGS INDICATE DENDRITIC
MOISTURE IS LACKING...AND WITH TEMPS NEAR/BELOW FREEZING AM
HESITANT TO INCLUDE FREEZING PCPN POTENTIAL AND WILL LEAVE FCST
DRY FOR NOW AND MONITOR TRENDS GIVEN THIS LOOKS LIKE MAINLY TRACE
AMNTS OF PCPN. WINDS SHIFT NW FOLLOWING FROPA WITH 6HR PRESSURE
RISES PROGGED NEAR 8MB. WINDY CONDITIONS WILL DEVELOP MONDAY IN A
TIGHT PRESSURE GRADIENT AS THE LOW MOVES INTO SOUTHERN MN.
FORECAST SOUNDINGS ON MONDAY SUGGEST MIXING NEAR H8 WITH WINDS AT
THE TOP OF THE LAYER PROGGED AROUND 45KTS. MONDAY LOOKS TO FEATURE
WINDY/COOLER CONDITIONS AND WILL NEED TO WATCH FOR POTENTIAL WIND
ADV.
PCPN CHCS MONDAY/MONDAY NIGHT WILL BE DEPENDENT UPON THE TRACK OF
THE UPPER LOW CROSSING THE PLAINS WITH THE NAM/ECMWF/GFS
ENSEMBLE FAVORING A FARTHER NORTH TRACK THAN THE GFS/GEM. FCST IS
BASED ON THE FARTHER NORTH TRACK OF SYSTEM IN LINE WITH NAM/EC/GEM
WITH SLIGHT CHCS/BUFFER POPS IN OUR NORTHERN/EASTERN ZONES ON THE
BACK SIDE OF THE LOW...AND IF NORTHERN TREND CONTINUES...MAY NOT
NEED POPS AT ALL IN DRY SLOT.
TUESDAY SHLD BE THE COLDEST OF THE WORKWEEK IN THE COLD AIRMASS
BEHIND THE SYSTEM AS A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE
PLAINS. TEMPS BEGIN TO RECOVER ON WEDNESDAY AS SFC RIDGE AXIS
SHIFTS EAST AND HEIGHTS RISE BEHIND THE DEPARTING LOW. THE PATTERN
ALOFT TRANSITIONS SOUTHWESTERLY BY THE END OF THE WORKWEEK AHEAD
OF AN UPPER TROUGH DEEPENING ALONG THE WEST COAST/SOUTHWEST CONUS.
WARM FRONTAL BOUNDARY LIFTS NORTHWARD WITH TEMPS EXPECTED TO TOP
OUT WELL INTO THE 40S/50S FOR THE LATTER PART OF THE WORKWEEK.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1216 AM CST SAT MAR 2 2013
ALTHOUGH EXPECT PREVAILING VFR CONDITIONS THROUGH THE MAJORITY OF
THE PERIOD...CONFIDENCE ESPECIALLY REGARDING VISIBILITY TRENDS
OVER THE NEXT 6-9 HOURS IS ADMITTEDLY SHAKY. AT LEAST SO FAR
TONIGHT...EARLIER INDICATIONS OF FAIRLY WIDESPREAD IFR TO LIFR
VISIBILITY/CEILING IN FOG HAS NOT COME TO FRUITION...AND CONSENSUS
OF LATEST MODELS SUGGESTS THAT KGRI MAY REMAIN JUST FAR ENOUGH
EAST TO AVOID A MAJOR DEGRADATION IN CONDITIONS. THAT BEING
SAID...GIVEN GENERALLY LIGHT/VARIABLE BREEZES WILL AT LEAST
MAINTAIN SEVERAL HOURS OF MVFR VISIBILITY POTENTIAL...AND AMEND
SHORT TERM TRENDS AS NEEDED. ASSUMING MAJOR FOG PROBLEMS DO NOT
ARISE...EXPECT ANY CEILINGS TO REMAIN VFR THROUGH THE
PERIOD...ALTHOUGH A BROKEN VFR DECK BELOW 10 THOUSAND FEET IS
POSSIBLE FOR PART OF THE DAY. ALTHOUGH SOME MODELS ARE ALREADY
INDICATING ADDITIONAL POTENTIAL FOR FOG TOWARD THE END OF THE
PERIOD MAINLY AFTER 03Z SATURDAY EVENING...CONFIDENCE IS NOT HIGH
IN THIS SCENARIO GIVEN SHAKY MODEL PERFORMANCE IN THE
NEAR-TERM...SO WILL DEFER TO LATER FORECASTS TO POSSIBLY INSERT
SATURDAY NIGHT FOG. SURFACE WINDS WILL NOT BE MUCH OF AN ISSUE
DURING THE PERIOD...WITH SOUTH-SOUTHWEST SPEEDS ONLY TOPPING OUT
AROUND 10KT DURING THE AFTERNOON INTO SATURDAY EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM...FAY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
801 PM CST SUN MAR 3 2013
.DISCUSSION...UPSTREAM OBSERVATIONS OVER SOUTHERN ALBERTA
ASSOCIATED WITH A PRESSURE BUBBLE RISE/ISALLOBARIC FORCING OF
6MB/3HR WILL IMPINGE OVER SOUTHWEST NORTH DAKOTA BY 18Z MONDAY.
THE RAP CAPTURES THIS NOW AND CONCUR WITH ITS TREND. SEVERAL
LOCATIONS IN SOUTHERN ALBERTA HAD SUSTAINED WINDS OF AROUND 30KT
ALONG WITH LIGHT SNOW. LIQUID AMOUNTS RANGED BETWEEN O.05 AND 0.10
WHICH IS IN LINE WITHE THE MODELS ACROSS THE SOUTHWEST MONDAY
AFTERNOON. FORECAST SOUNDINGS IN THE SOUTHWEST SHOW SUSTAINED
WINDS IN THE 30KT RANGE WITH POSSIBLE GUSTS TO 45KT. DECIDED TO
ISSUE A WINTER WEATHER ADVISORY FOR BLOWING SNOW FOR OUR SOUTHWEST
COUNTIES OF SLOPE/BOWMAN/ADAMS FROM 18Z MONDAY THROUGH 12Z
TUESDAY. FEEL THIS IS THE MOST APPROPRIATE ADVISORY AS IT COVERS
THE SUSTAINED WINDS IN THE 30 MPH RANGE...AND EXPECTED VISIBILITY
REDUCTIONS TO ONE HALF MILE OR LESS FOR THE AFTERNOON AND EVENING
HOURS IN FALLING SNOW.
OTHERWISE...COLD FRONT IS NOW JUST PAST BEACH WITH RAIN AND WIND
GUSTS TO AROUND 30 MPH. THE MAIN PRESSURE RISE ASSOCIATED WITH
THOSE WINDS WILL SLIDE ACROSS SOUTHEAST MONTANA THROUGH 06Z.
BOWMAN RADAR SHOWING A LARGE SWATH OF RAIN WITH A POSSIBLE
LIGHTNING STRIKE OR TWO NEAR THE SOUTHWEST BORDER. WILL CONTINUE
TO WATCH THIS CLOSELY.
CURRENT FORECAST REMAINS ON TRACK WITH RAIN CHANGING TO SNOW NORTH
TO SOUTH OVERNIGHT...HEAVIEST IN THE NORTH AND EAST CENTRAL TONIGHT
THROUGH MONDAY NIGHT. THE DRY SLOT IS STILL ADVERTISED IN THE FAR
SOUTHWEST AND SOUTH CENTRAL MONDAY MORNING INTO THE EARLY AFTERNOON.
UPDATES FORTHCOMING.
&&
.AVIATION...EXPECTING SIGNIFICANT AVIATION PROBLEMS OVER THE NEXT
24 TO 36 HOURS. CIGS WILL GENERALLY DETERIORATE INTO THE IFR/LIFR
RANGE IN MODERATE TO HEAVY SNOW AT TIMES FOR KMOT/KJMS SUNDAY NIGHT.
RAIN WILL CHANGE TO SNOW AT KISN AROUND 03Z...AND AROUND 05Z-06Z AT
KDIK AND KBIS. VSBYS WILL DEGRADE INTO THE LIFR RANGE AT KMOT/KJMS
AND IFR FOR KBIS/KDIK/KISN TONIGHT. STRONG NORTHERLY WINDS MONDAY
AFTERNOON WITH ANOTHER ROUND OF SNOW WILL RESULT IN LIFR/VLIFR
VSBYS AT KISN/KMOT/KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ017>020-031>035-041-042-045>047-050.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR NDZ001>005-
009>013-021>023-025-036-037-048-051.
WINTER WEATHER ADVISORY FROM 11 AM MONDAY TO 5 AM MST TUESDAY
FOR NDZ040-043-044.
&&
$$
DISCUSSION/AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
537 PM CST SUN MAR 3 2013
.DISCUSSION...THE RAP AND GFS IN LINE WITH THE LATEST WATER VAPOR
IMAGERY...DEPICTING THE UPPER LOW CIRCULATING OVER SOUTHEASTERN
ALBERTA...WHILE A COLD FRONT AT THE SURFACE WHICH WAS APPROACHING
MILES CITY AND GLENDIVE MONTANA. AHEAD OF THE COLD FRONT
TEMPERATURES ARE IN THE MID 50S FROM EASTERN MONTANA...AND MID TO
UPPER 40S IN WESTERN/SOUTHWESTERN NORTH DAKOTA. CONVECTION ALONG
THE FRONT HAS PROMPTED A SMALL SEVERE THUNDERSTORM AREA EAST OF
BILLINGS. FURTHER AWAY FROM THE THUNDERSTORMS...JORDAN MONTANA HAD
GUSTS TO 36KT AS THE COLD FRONT PAST THROUGH. WILL BE WATCHING
THIS AREA AS IT APPROACHES WESTERN NORTH DAKOTA EARLY THIS EVENING.
LATEST RAP SOUNDINGS SHOW RAIN FOR DICKINSON AND BISMARCK THROUGH
THE EVENING BEFORE CHANGING TO SNOW BETWEEN 04Z-06Z MONDAY. WILLISTON
ON TRACK FOR A CHANGEOVER TO SNOW THIS EVENING. MINOT AND JAMESTOWN
WILL REMAIN COLD ENOUGH FOR ALL SNOW. HEAVIEST SNOW AMOUNTS STILL
PROJECTED OVER THE NORTH CENTRAL COUNTIES TONIGHT THROUGH MONDAY
NIGHT...AND INTO THE NORTHERN JAMES RIVER VALLEY...THIS IS WHERE
THE MAX OMEGA COINCIDES WITH THE DENDRITIC GROWTH ZONE RESULTING
IN MODERATE TO HEAVY SNOW AT TIMES.
LOOKING FURTHER AHEAD...ANOTHER CONCERN WILL BE WHAT TO DO WITH
THE FAR SOUTHWEST MONDAY AFTERNOON/EVENING AS STRONG WINDS ARE
FORECAST ALONG WITH SOME SNOW. CURRENTLY THE FAR SOUTHWEST IS ON
THE FRINGES OF A HIGH-END WIND ADVISORY/POSSIBLE LOW-END HIGH WIND
WARNING...AND IF THERE IS ENOUGH SNOW FALLING DURING THIS TIME...A
WINTER WEATHER ADVISORY MAY BE MORE APPROPRIATE AS VSBYS WILL BE
AFFECTED FOR MUCH OF THE AFTERNOON. WILL LOOK MORE AT THIS DURING
THE EVENING.
REST OF HEADLINES CURRENTLY IN GOOD SHAPE.
&&
.AVIATION...EXPECTING SIGNIFICANT AVIATION PROBLEMS OVER THE NEXT
24 TO 36 HOURS. CIGS WILL GENERALLY DETERIORATE INTO THE IFR/LIFR
RANGE IN MODERATE TO HEAVY SNOW AT TIMES FOR KMOT/KJMS SUNDAY NIGHT.
RAIN WILL CHANGE TO SNOW AT KISN AROUND 02Z...BY 05Z AT KDIK...AND
06Z AT KBIS. VSBYS WILL DEGRADE INTO THE LIFR RANGE AT KMOT/KJMS
AND IFR FOR KBIS/KDIK/KISN TONIGHT. STRONG NORTHERLY WINDS MONDAY
AFTERNOON WITH ANOTHER ROUND OF SNOW WILL RESULT IN LIFR/VLIFR
VSBYS AT KISN/KMOT/KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST /5 AM MST/ TUESDAY FOR
NDZ017>020-031>035-041-042-045>047-050.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR NDZ001>005-
009>013-021>023-025-036-037-048-051.
&&
$$
DISCUSSION/AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
335 PM CST SAT MAR 2 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY
MAIN FORECAST ISSUES ARE RELATED TO TIMING...LOCATION AND PRECIP
AMOUNTS WITH THE APPROACHING WINTER STORM... EXPECTED TO IMPACT THE
AREA FROM LATE SUNDAY THROUGH EARLY TUESDAY.
FOR TONIGHT... PATCHY LIGHT SNOW OR SNOW FLURRIES ARE POSSIBLE
THROUGH EARLY EVENING ACROSS NORTHWEST TO NCNTRL MN WITH VARIABLE
CLOUDS AND LIGHT EAST SOUTHEAST WINDS OVER ERN ND AND THE RED RIVER
VALLEY CORRIDOR.
SUNDAY...CLOUDS SHOULD INCREASE THROUGH THE DAY AS THE NEXT STORM
SYSTEM APPROACHES. WITH LIGTH TO MODERATE SOUTH SOUTHEAST BLAYER
FLOW AND MIXED CLOUDS EARLY... EXPECT TEMPS TO WARM TO NEAR SEASONAL
NORMALS THROUGH THE FA.
SUNDAY NIGHT AND MONDAY...HAVE GENERALLY USED A MODEL BLEND OF THE
12Z NAM...GFS AND ECMWF TO ACHIEVE A COHERENT PICTURE OF SNOWFALL
AMOUNTS AND TIMING ACROSS THE AREA. OVER THE PAST FEW MODEL CYCLES
THE NAM HAS FAVORED HEAVIER AMOUNTS IN THE NORTH VALLEY WHILE THE
GFS HAS FAVORED THE SOUTH VALLEY. A MODEL BLEND PRODUCES WIDESPREAD
6 TO 10 INCH SNOWFALLS ACROSS ALL OF CNTRL AND ERN ND INTO THE RED
RIVER BASIN AND THEN SOUTHEASTWARD CLOSE TO THE I-94 AND HWY 10
CORRIDORS. THE LOW PRESSURE SYSTEM SOMEWHAT RESEMBLES AN ALBERTA
CLIPPER... BUT WITH SLOWER OVERALL SPEED AND ABUNDANT LOW LEVEL
MOISTURE FEED... LOOKS ABLE TO PRODUCE HEAVIER SNOWFALL AMOUNTS.
MONDAY NIGHT AND TUESDAY...STILL SOME LIGHT SNOW AND BLOWING SNOW
POTENTIAL AS SYSTEM EXITS THE AREA. ABSENCE OF TRAILING DENSE AND
COLD AIRMASS REDUCES THE THREAT OF SIGNIFICANT BLOWING AND DRIFTING.
HOWEVER... WILL NEED TO BE WATCHED AS MODELS INDICATE SOEM POTENTIAL
FOR AN OVERALL DEEPER LOW PRESSURE AND SOMEWHAT HIGHER WINDS.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
MEDIUM-RANGE MODELS NOT IN THE BEST OF AGREEMENT NEXT WEEK...BUT
OVERALL SYNOPTIC PATTERN SHOWS NORTHWEST FLOW ALOFT ON WEDNESDAY
TRANSITIONING TO THE SOUTHWEST FOR THURSDAY AS A SHORT-WAVE RIDGE
MOVES ACROSS THE NORTHERN PLAINS. WILL SEE LOW (20 TO 30 PERCENT)
SNOW CHANCES THURSDAY AND EARLY FRIDAY ACROSS THE NORTH AS A
NORTHERN ROCKIES SURFACE LOW MOVES ACROSS THE DAKOTAS. OTHERWISE...
EXPECT MOSTLY DRY CONDITIONS. A SPLIT-FLOW REGIME DEVELOPS FRIDAY/
SATURDAY AND THIS SHOULD KEEP THE PRIMARY STORM TRACK ACROSS THE
SOUTHERN CONUS AS A LARGE LOW DEVELOPS ACROSS THE FOUR CORNERS. NO
BIG SWINGS IN AIR MASSES...SO EXPECT MINIMAL DAY-TO-DAY TEMPERATURE
CHANGES WITH DAYTIME HIGHS IN THE 20S AND LOWER 30S AND NIGHTTIME
LOWS IN THE SINGLE DIGITS TO TEENS ABOVE ZERO.
&&
.AVIATION...
ALL MODELS OVERESTIMATING LOW CLOUDS IN THE BOUNDARY LAYER THIS
AFTERNOON WITH THE LATEST RAP SEEMING TO HAVE THE BEST HANDLE ON
CURRENT CONDITIONS. IT SHOWS A BAND OF MVFR/IFR CEILINGS MOVING
INTO THE VALLEY THIS EVENING AND OVERNIGHT. HOWEVER...CONFIDENCE
IN THIS SCENARIO IS LOW GIVEN CURRENT MODEL PERFORMANCE. WILL
MAINTAIN A VFR PERSISTENCE FORECAST AT THIS TIME...BUT LOWER
CEILINGS MAY NEED TO BE INTRODUCED LATER TONIGHT. SOUTH-SOUTHEAST
WIND WILL PERSIST THROUGH THE NIGHT BETWEEN 5 AND 15 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
NIGHT FOR NDZ006>008-014>016-024-026>030-038-039-049-052>054.
MN...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
NIGHT FOR MNZ001>004-007-008-013>015-022-027>032-040.
&&
$$
GUST/ROGERS/WJB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1035 AM CST SAT MAR 2 2013
.DISCUSSION...
THROUGH 16Z...SFC HIGH PRESSURE RIDGE EXTENDS SOUTHWARD ACROSS WRN
ONT AND ERN MN INTO CNTRL IA...WITH LOW LOW PRESSURE DIGGING INTO
THE WRN DKTAS. SOUTHERLY WINDS ARE PICKING UP ACROSS ERN ND AND THE
RRV CORRIDOR AND MORING EMP RECOVERY IS WELL UNDERWAY. SAT IMAGERY
SHOWS N/S ORIENTED WARM FRONTAL MID TO UPR LVL CLOUD BAND STRETCHING
ACROSS ERN ND/SD INTO WRN EDGE OF MN. A FEW SITES HAVE REPORTED
BRIEF PERIODS OF VERY LIGHT SNOW OUT OF MAINLY VFR CIGS. RADAR
INDICATES THAT THIS WEAKLY FORCED LIGHT PRECIP BAND IS MAINLY IN THE
COUNTIES STRADDLING THE ND/MN BORDER ATTM...WITH A VERY SLOW EWD
PROGRESSION INDICATED.
REST OF TDY...12Z NAM AND RAP GUIDANCE SHOWING GOOD AGREEMENT WITH
CURRENT WARM FRONTAL BAND AND SHOW LIGHT PRECIP AND MID LVL CLOUDS
PROGRESSING ACROSS THE RRV THROUGH MIDDAY AND SLOLY EDGING EWD ACROSS
NW MN DURING THE AFTERNOON. SOME MID LVL DRYING IS CURRENTLY EVIDENT
ACROSS CNTRL ND WHICH IS NOT WELL DEPICTED IN MODEL GUIDANCE. WILL
UPDATE FCST GRIDS TO SHOW SOME RECUCTION IN CLOUDS /PATCHY SUNSHINE/
OVER ERN ND THROUGH EARLY AFTERNOON. CLOUDS SHOULD INCREASE AGAIN
THROUUGH LATE AFTERNOON... AHEAD OF THE APPROACHING STORM SYSTEM.
TONIGHT INTO SUNDAY...12Z NAM CONTINUES TO BE THE MORE NORTHERN SOLN
FOR THE TRACK OF OUR NEXT STORM SYSTEM. WILL ADDRESS ANY ADJUSTMENTS
TO FORECAST TRACK...INTENSITY AND PRECIP AMOUNTS WITH AFTERNOON
PACKAGE. OTHERWISE...EXPECT CLDS TO THICKEN IN OVER THE AREA AND
WINDS BECOME VARIABLE OUT OF THE EAST SOUTHEAST AS AREA RESPONDS TO
DEEPENING LOW PRESSURE IN EASTERN MT AND WRN ND.
&&
.AVIATION...
FOG ACROSS THE AREA THIS MORNING HAS DISSIPATED...BUT STILL MAY SEE
SOME REDUCTION IN VISIBILITY DUE TO BR/HZ IN THE 4 TO 6 SM RANGE
ALONG THE VALLEY FLOOR. SOME MID CLOUDS AND BRIEF MVFR CEILINGS MAY
SPREAD INTO THE VALLEY WITH WARM FRONT AND SOME PATCHY LIGHT SNOW
THIS AFTERNOON. SOUTHEAST TO SOUTH WINDS WILL INCREASE TO NEAR 15 KTS
IN THE VALLEY MIDDAY-AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 343 AM CST SAT MAR 2 2013/
SUNDAY WILL SEE WINDS INCREASE FROM THE SOUTHEAST AHD OF NEXT
SYSTEM. EARLY THIS SATURDAY MORNING WATER VAPOR SHOWS A STRONG PLUME
OF MOISTURE FROM THE TROPICS NORTH INTO WCNTRL BRITISH COLUMBIA.
MAIN SHORT WAVE SEEN OFF SHORE OF CNTRL B.C. COAST AND IT IS THIS
SHORT WAVE WHICH MODELS CONTINUE TO HAVE ISSUES WITH IN HOW MUCH TO
DIG IT SOUTH OR KEEP IT FARTHER NORTH. 00Z EURO CAME IN SLOWER AND
FARTHER NORTH THAN PREV RUN AND ALMOST A COMPROMISE BTWN
NAM/GFS/GEM. USING 00Z EURO WOULD HAVE SFC AND UPR LOW IN SRN
ALBERTA 18Z SUN AND THEM MOVING EAST-SOUTHEAST INTO WRN ND 06Z MON
THEN MOVING SFC-UPR LOW INTO EITHER NE SD OR SE ND REGION 18Z MON.
USING THIS CONSENSUS MODEL APPROACH WOULD BRING SIGNIFCANT SNOWS
FARTHER NORTH INTO MOST OF ERN ND AND PARTS OF WCNTRL MN. PER COORD
WITH OTHER OFFICES AND CONSIDERING WE HAVE HAD TWO SPECIAL WEATHER
STATEMENTS FOR THIS EVENT ON FRIDAY FEEL LIKE THE NEXT STEP IS WATCH
PHASE. SO ISSUED A WINTER STORM WATCH FOR SUN NIGHT-MON NIGHT FOR
ALL OF ERN ND INTO WCNTRL MN....GENERALLY WEST OF A
HALLOCK-FOSSTON-WADENA LINE. STILL A LOT COULD CHANGE...BUT THAT
AREA ABOVE IS AT LEAST 50 PCT CONFIDENCE RANGE OF GETTING WARNING
CONDITIONS. WINDS DONT APPEAR STRONG WITH THIS SYSTEM AND SNOWFALL
SPREAD OUT OVER A 18-24 PD BUT CERTAINLY 6+ INCH AMOUNTS APPEAR
LIKELY.
.LONG TERM...TUESDAY THROUGH FRIDAY
LONG RANGE PERIOD STARTS WITH SYSTEM MOVING OUT OF THE FA. EXPECT
LIGHT SNOW TO LINGER ACROSS EASTERN ZONES. MODELS SUGGEST A TROUGH
ASSOCIATED WITH DEPARTING UPPER LOW. AS HAS BEEN THE CASE RECENTLY
VARIED SOLUTIONS EXIST...YET ECMWF/GEM/DGEX SHOWING MOISTURE AND
ISENTROPIC UPGLIDE SUFFICIENT TO WARRANT POPS. HIGH BUILDS IN DRYING
THE COLUMN AND DECREASING WINDS. LOWERED TEMPERATURES A BIT
WEDNESDAY MORNING AS SURFACE RIDGE FORECAST TO LAY ALONG AND EAST OF
CWFA.
RETURN FLOW QUICKLY SETS IN AFTER 00Z THURSDAY...WITH LOW LEVEL WAA
HOLDING STEADY INTO EVENING. MODELS CONTINUE TO OFFER A VARIETY OF
SOLUTIONS FOR LATER IN THE WEEK. GENERAL CONSENSUS IS FOR
PRECIPITATION TO AGAIN BREAK OUT THURSDAY WITH SOUTHWEST FLOW ALOFT.
SURFACE TROUGH / LOW OVER FA...INCREASING MOISTURE AND LIFT ARGUE
FOR THE 20 TO 30 POPS DEPICTED BY BLENDS. WARMING COLUMN COULD
RESULT IN -RA MIX CLOSER TO THE BOUNDARY OVER SOUTHERN FA. YET WITH
HIGH LEVEL OF UNCERTAINTY KEPT PRECIP ALL -SN FOR NOW.
LINGERING -SN POSSIBLE INTO FRIDAY AS UPPER SHORT WAVE MOVES ACROSS
NORTHEAST CWFA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
NIGHT FOR NDZ006>008-014>016-024-026>030-038-039-049-052>054.
MN...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY
NIGHT FOR MNZ001>003-027-029>031-040.
&&
$$
GUST/ROGERS/WJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
833 PM EST SUN MAR 3 2013
.SYNOPSIS...
A SLOW MOVING UPPER LOW OVER THE NORTHEASTERN STATES WILL EXIT OFF
THE NEW ENGLAND COAST BY LATE MONDAY ALLOWING WEAK HIGH PRESSURE
TO BUILD ACROSS THE LOCAL AREA. LOW PRESSURE WILL DEVELOP IN THE
HIGH PLAINS SUNDAY AND MONDAY AND TAKE A TRACK THROUGH THE OHIO
VALLEY AND MID-ATLANTIC STATES TUESDAY NIGHT AND WEDNESDAY. THIS
STORM WILL PROBABLY PASS TO THE SOUTH OF THE STATE...BUT WILL MOST
LIKELY BRING SNOW INTO SOUTHERN PENNSYLVANIA IN THE MIDDLE OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FORECAST STRONGLY CONTINUOUS...AND FLURRIES OR LIGHT SNOW EXPECTED
FOR THE ENTIRE NIGHT. RECENT HRRR AND RUC/RAP HAVE BEEN INDICATING
THAT WE COULD GET SOME ENHANCED LLVL OMEGA THIS EVENING AS AN
UPPER LEVEL LOW FILLS AND PASSES N-S THRU OH. WILL KEEP POPS HIGH
THEN PLAY A GRADUAL DECREASE IN POPS/SNOW INTENSITY AND AMOUNTS
AFTER MIDNIGHT. BUT THE FLOW DOES NOT CHANGE DIRECTION AND THE
PRES GRADIENT STAYS TIGHT. SHOULD BE BREEZY WITH 10MPH+ WINDS ALL
NIGHT. THE FLUFFINESS OF THE SNOW IN THIS DRY AIR MASS AND COLD
CLOUD TEMPS RESULTED IN SLR/S IN THE 30:1 RANGE SUN MORNING.
THEREFORE...ACCUMS OF A DUSTING TO AN INCH PROBABLE OVER THE NWRN
HALF OF THE AREA...WITH 1-3 IN THE FAR NRN TIER AND IN THE
LAURELS. TEMPS ALREADY BELOW NORMALS...BUT CLOUD COVER WILL HELP
TO KEEP THEM GOING TOO FAR BELOW NORMAL MINS BY MON MORNING.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
SFC HIGH PRESSURE RIDGE TO THE WEST INCHES CLOSER AND 5H HEIGHTS
RISE GREATLY OVER THE GREAT LAKES AND OH VALLEY AND SOMEWHAT HERE
AS WELL. LLVL PRES GRADIENT STAYS TIGHT DURING THE DAY AND MIXING
DEEPER THAN SUNDAY SHOULD ENHANCE THE WINDS IN THE AFTN. THE CLOUD
DECK WILL BECOME MORE-DIFFUSE THROUGH THE MORNING AND CLEARING
POSSIBLE ACROSS THE SOUTH AND EAST-CENTRAL COS IN THE AFTN. NW
FLOW STILL DOMINATES MUCH OF THE DAY...BUT RELAXES AND BECOMES
SLIGHTLY ANTI-CYCLONIC LATER IN THE DAY. THIS ALSO POINTS TO A
SUBSIDENCE OF THE SHSN...BUT THEY WILL LIKELY HOLD ON LONGEST IN
THE NRN TIER. CLOUDS WILL LINGER EVEN LONGER...PERHAPS STAYING
NEAR 100PCT THRU THE EVENING HRS. WILL CONTINUE TO MENTION LIGHT
ACCUMS AND LIKELY POPS IN THE MTNS IN THE MORNING...BUT TAPER THEM
OFF LATER. DUE TO THE POSSIBILITY OF SUN IN THE SRN TIER AND ESP
THE SE...TEMPS SHOULD GET A LITTLE MILDER - BUT STILL BELOW NORMAL
ON MONDAY AFTN.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
REX BLOCK FROM THE CANADIAN MARITIMES SOUTH TO THE NEW ENGLAND COAST
WILL TEMPORARILY BREAK DOWN AS A VIGOROUS CHUNK OF UPPER ENERGY
DIVES SOUTHEAST ACROSS THE ROCKIES AND CARVES OUT A POTENT UPPER LOW
CENTER...WHICH TRACKS EAST FROM THE MID MISS VALLEY TO THE MID
ATLANTIC COAST BY LATE WEDNESDAY NIGHT.
FOR MONDAY NIGHT AND TUESDAY...THE PERSISTENT/COLD NWRLY FLOW WILL
RELAX AND AT LEAST PARTIAL CLEARING WILL OCCUR AS A RIDGE OF HIGH
PRESSURE AT THE SFC AND ALOFT SLIDES EAST ACROSS THE COMMONWEALTH.
U.S. MODELS AND ENSEMBLES HOPEFULLY CAN HANDLE THE UPCOMING CRITICAL
/HOME COURT/ WEATHER FOR THE MID-WEEK PERIOD BETTER THAN THE
ADMIRABLE RECORD OF THE /VISITING TEAM/ MODELS.../EC AND UKMET/.
THE 00Z THROUGH 12Z SREF AND GEFS...ALONG WITH THE OPERATIONAL
NAM/GFS AND UKMET HAVE BEEN IN FAIRLY GOOD AGREEMENT AND CLUSTERED
FURTHER NORTH WITH THE SFC/UPR LOW TRACK AND RESULTANT NORTHERN EDGE
OF THE SHIELD OF HEAVY SNOW...COMPARED TO THE EC/UKMET WHICH BARELY
BRUSHES EXTREME SOUTHERN PA AND THE LAURELS WITH A FEW TO SVRL
INCHES OF SNOW LATE TUESDAY THROUGH WEDNESDAY.
THE FOCUS FOR OUR WEATHER...AND SOMEWHAT HIGH DEGREE OF CONFIDENCE
FOR THE SOUTHERN 1-2 LAYERS OF COUNTIES GETTING INTO THE NORTHERN
EDGE OF MDT TO HVY SNOW ACTION...RESTS ON THE VERIFICATION/PLACEMENT
OF THE CONSISTENT AND HIGHLY ANOMALOUS /-3 TO -4 SIGMA/ EASTERLY
925-850 MB FLOW THAT/S BEEN CONSISTENTLY SHOWN AND AIMED INTO
SOUTHERN PENN AND POINTS SOUTH THE PAST FEW ENSEMBLE AND U.S.
OPERATIONAL MODEL RUNS.
THE PASSAGE OF THE LEFT EXIT REGION OF A HIGHLY CYCLONIC AND STRONG
120+ KT 300 MB JET...AND ASSOCIATED/PERSISTENT 850-700 MB FGEN
FORCING ACROSS SRN PA SUPPORTS THE LIKELIHOOD OF AN EXTENDED...18-24
HR PERIOD OF ENHANCED SNOWFALL NEAR AND TO THE SOUTH OF ROUTE 22 IN
SCENT PENN.
ACROSS THE CENTRAL THIRD OF THE STATE...EXPECT LIGHTER SNOW OF A FEW
TO SEVERAL INCHES UP TO AROUND THE I-80 CORRIDOR.
THE LATEST ENSEMBLE GUIDANCE /06-12Z GEFS AND 03-15Z SREF/ CONTINUE
TO BE THE HIGH-END...NORTHERN OUTLIERS DISPLAYING A MEAN LIQUID
EQUIVALENT 24 HR QPF OF 0.5 OF AN INCH NEAR AND JUST TO THE SOUTH OF
I-80...WHILE EARLIER RUNS LEADING UP TO AND INCLUDING THE 12Z GEFS
DEPICTED THE 24 HR 1-INCH CONTOUR BRUSHING THE MASON DIXON LINE OF
SCENT AND SERN PA.
THE FRESH IN...15Z RUN OF THE SREF HAS TRENDED EVEN FARTHER NORTH
WITH THE MODERATE TO HEAVY QPF /AND POTENTIALLY VERY SNOWFALL/ AND
NOW PLACES THE 1 INCH QPF CONTOUR AS FAR NORTH AND WEST AS KUNV AND
KJST...EAST TO KLNS. THIS IS SUPPORTED BY A SLIGHT NORTHERN SHIFT
AND STRENGTHENING TO THE 850 EASTERLY JET...WHICH IS NOW SHOWN TO BE
A WHOPPING -5 TO -6 SIGMA ACROSS SERN PA AT 18Z WED. WON`T BUY INTO
THESE MUCH HIGHER AMOUNTS NORTH OF THE PENN TURNPIKE JUST YET...AND
WOULD RATHER TAKE THE MORE PRUDENT AND CONSERVATIVE ROUTE
CONSIDERING THE LARGE...AND PERSISTENT DISAGREEMENT BY THE 00Z-12Z
EURO MODELS WITH THEIR MORE SOUTHERN TRACK.
THE FEATURE THAT SEEMS TO BE ONE OF THE MOST CONSISTENT ON THE SREF
AND GEFS /SUPPORTING MODERATE TO HEAVY SNOW SPREADING ACROSS THE SRN
THIRD TO HALF OF PENN/ HAS BEEN THE TRACK OF THE 250 MB LOW CENTER
RIGHT OVER KCMH AND KMGW LATE TUESDAY NIGHT AND WED MORNING...WHICH
PLACES CENTRAL AND SOUTHERN PENN UNDER AN EXTREMELY DIFFLUENT UPPER
FLOW AND MAINTAINS A DEEP EAST TO NE FLOW LATE TUESDAY NIGHT THROUGH
MUCH OF WED.
THE MAIN CONCERN USING THE ENSEMBLE QPF MEAN /AND AMOUNTS TWD THE
NRN EDGE OF THE PRECIP SHIELD/ IS THE LIKELY CONTAMINATION/SKEWING
BY A FEW OF THE EXCESSIVELY HIGH END MEMBERS THAT SHOW OVER 2.0
INCHES OF LEQ FOR CENTRAL AND SOUTHERN PENN.
USING A /MEDIAN/ VALUE...OR MEAN BY REMOVING A FEW OF THE VERY HIGH
AND LOW END MEMBERS TRIMS SOME OF THE EXCESS FAT /SNOWFALL/ FROM THE
NRN EDGE. THIS IS NOT TO SAY THAT THESE FRINGE ENSEMBLE MEMBERS
DON/T PROVIDE VALUABLE INSIGHT INTO THE POTENTIAL MAGNITUDE OF THE
STORM. RATHER...ON THE WHOLE...THEY BROAD-BRUSH HIGHER AMOUNTS TOO
FAR TO THE NORTH.
THE LATEST HWOCTP INDICATES THE GENERAL EXPECTED SNOWFALL FROM NORTH
TO SOUTH ACROSS THE STATE...AND OUR GRIDDED STORM TOTAL SNOWFALL IS
CONSERVATIVELY PLACED A FAIR AMOUNT BELOW THE OPERATIONAL
GFS/NAM/SREF AND GEFS MEAN. INITIAL ESTIMATES OF STORM TOTAL
SNOWFALL VARY FROM JUST A FEW INCHES NEAR AND TO THE NE OF KIPT...TO
BETWEEN 8-11 INCHES ACROSS THE SOUTHERN TIER COUNTIES /WITH A
GENERAL 3-6 INCHES NEAR AND JUST TO THE SOUTH OF A SEG-KUNV-KFIG
LINE.
AGAIN...ALL EYES WILL BE ON THE TRENDS OF THE LATER RUNS...ESP THE
SOUTHERN OUTLIERS - EC AND UKMET.
A CHILLY AND RATHER GUSTY NORTHERLY FLOW WITH ISOLATED TO SCATTERED
MTN SNOW SHOWERS FOLLOWS FOR THURSDAY...BEFORE HEIGHTS RISE AND
DAYTIME TEMPS MODERATE TO NEAR NORMAL BY FRIDAY AND SATURDAY. A FAST
MOVING AND RELATIVELY FLAT/WEAK NRN STREAM SHORTWAVE WILL TRACK
ACROSS THE GREAT LAKES AND NRN PENN SATURDAY INTO SATURDAY
NIGHT...POSSIBLY ACCOMPANIED BY A FEW SHOWERS OF RAIN AND WET SNOW
UP NORTH. SOUTHERN PORTIONS OF PENN SHOULD STAY MAINLY DRY THROUGH
THE WEEKEND...AFTER THE POTENTIAL HIGH IMPACT/HEAVY SNOW EVENT OF
LATE TUESDAY INTO EARLY THURSDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
PERSISTENCE FORECAST REMAINS THE PHRASE FOR THE FCST PERIOD.
CLIMO NW FLOW PATTERN YIELDS GENERALLY MVFR/IFR CIGS IN BFD/JST
AND MVFR IN AOO/UNV. DRYING ON DOWNSLOPE WINDS WILL KEEP GENERALLY
KEEP VFR CONDITIONS AT IPT/MDT/LNS. PRES GRADIENT WILL KEEP WINDS
IN THE 10-15KT RANGE WITH OCCASIONAL GUSTS INTO THE 20S ALMOST
EVERYWHERE EVEN OVERNIGHT. THE GRADIENT DOES NOT SLACKEN THROUGH
THE NIGHT NOR ON MONDAY.
THINGS TO PICK OUT AS POTENTIAL ENHANCEMENTS TO THIS FORECAST ARE
A SLIGHT INCREASE IN UPSLOPE FLOW AND UPLIFT IN THE WRN MTS THIS
EVENING. THIS HAS RESULTED IN A FEW HOUR PERIOD OF WORSE FCST
CONDITIONS FOR THOSE LOCATIONS - BUT EVEN THAT NEVER DROPS ANY
SITE TO LIFR. SOME IFR VSBYS ARE LIKELY OVERNIGHT IN SNOW SHOWERS
MAINLY AT JST AND BFD.
MONDAY WILL BRING SIGNIFICANT IMPROVEMENT TO FLYING CONDITIONS AS
CIGS AND VSBYS LIFT. CYCLONIC LLVL FLOW WILL MOVE EAST OF THE
REGION AND BE REPLACED BY A WEAK HIGH PRESSURE SYSTEM. LAKE
MOISTURE WILL STILL BE DRAWN DOWN FROM THE N...KEEPING VFR CLOUDS/CIGS
OVER THE NRN TIER...BUT SERN TERMINALS WILL CLEAR OUT BY THE LATE
AFTN...AND EVEN JST MIGHT SCATTER-OUT. HIGH PRES AXIS MAKES IT
OVERHEAD TUES AM...WITH LITTLE CLOUD AND ONLY LIGHT WIND IN
STORE.
OUTLOOK...
TUE...CLOUDS INCREASE W-E LATE.
TUE NIGHT-WED NIGHT...SIG RESTRICTIONS POSS SOUTH IN S+
THU...MVFR N...VFR ELSEWHERE.
FRI...NSW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/RXR
NEAR TERM...DANGELO/RXR
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1251 PM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
REACHING THE THE EAST COAST LATE SUNDAY. HIGH PRESSURE WILL BRIEFLY
MOVE INTO THE AREA ON MONDAY AHEAD OF A LOW PRESSURE SYSTEM THAT
WILL DEVELOP OVER THE MID MISSISSIPPI RIVER VALLEY. THIS LOW IS
EXPECTED TO QUICKLY CROSS THE AREA ON WEDNESDAY WITH COLD HIGH
PRESSURE FILLING IN BEHIND IT ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM...THE AXIS OF THE MID-UPR VORT LOBE IS JUST ABOUT TO
EXIT THE SE CORNER OF THE CWFA. A NICE LITTLE SNOW BAND CONSOLIDATED
FROM THE LAURENS AREA...ENE THRU ROCK HILL AND INTO MONROE NC. THERE
HAVE BEEN A FEW REPORTS OF UP TO 1.5" OF SNOW ACCUM WITH THE BAND.
BUT ROADS SEEM TO BE STAYING WET. THE BAND LOOKS TO BE PICKING UP
SOME SPEED...AS IT SHIFTS TO THE SE...AND MAY BE LOSING SOME
INTENSITY. SO NOT EXPECTING ANY MAJOR IMPACTS WITH IT FOR THE REST
OF ITS TRACK THRU THE REMAINDER OF THE CWFA.
IN THE WAKE OF THE VORT LOBE...CLEARING HAS BEEN OCCURRING ACRS MUCH
OF THE BLUE RIDGE ESCARPMENT AND ADJACENT FOOTHILLS FROM NE GA UP
THRU WRN NC. THE INSOLATION IS QUICKLY DESTABILIZING THE BL...WITH
LAPS ALREADY SHOWING 100-150 J/KG OF CAPE AT 16Z. THE LTST RAP SEEMS
TO BE INITIALIZING BOTH THE QPF AND THE INSTBY THE BEST...AND IT
DOES HAVE UP TO 200-300 J/KG OF CAPE THIS AFTN ACRS THE PIEDMONT
WITH ENUF CONVERGENCE FOR SHWR DEVELOPMENT. THE MAIN LIMITING FACTOR
APPEARS TO BE THE MID AND UPR SUPPORT WILL BE LACKING. EVEN THE
NAM...WHICH INITIALIZES ANOTHER VORT MAX OVR ERN TN...DOES NOT
TRANSLATE THAT FEATURE INTO APPRECIABLE QG FORCING ACRS THE CWFA
THIS AFTN. SO I TRIMMED POPS BACK SLIGHTLY IN THE WEST...BUT OPTED
TO KEEP A HIGH-END CHC TO LIKELY POP IN THE EAST LATER FOR NOW (DUE
TO THE INSTBY AND HI-RES MODELS DEPICTING CONVECTION). THE UPSHOT IS
THAT THE WINTER WX ADV FOR THE SRN NC MTNS/NE GA AND SC MTNS CAN BE
CANCELLED. THE REST OF THE ADV LOOKS GOOD THRU 6 PM...GIVEN THE
CONVECTIVE TRENDS ON THE MRX RADAR.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...THE BAND OF SNOW AND ASSOCIATED RESTRICTIONS HAS PUSHED
OFF TO THE SE...ALLOWING KCLT TO GO TO VFR BEFORE THE 18Z TAF
ISSUANCE. THERE IS STILL SOME LOW CLOUDS ACRS THE REGION PER
METARS...SO I WILL KEEP AN HOUR TEMPO FOR MVFR CIGS. OTHERWISE...THE
MAIN CONCERN WILL BE ANOTHER ROUND OF PRECIP THIS AFTN IN THE FORM
OF SCATTERED TO NUMEROUS SHOWERS. MOST OF THE ACTIVITY SHUD REMAIN
LIGHT RAIN...BUT THE HEAVIEST SHOWERS COULD PRODUCE SNOW/GRAUPEL
MIX. CONFIDENCE ON ONE OF THOSE HITTING THE TERMINAL IS TOO LOW TO
MENTION IN THE TAF AT THIS TIME. SO OVERALL EXPECTING VFR THRU THE
PERIOD. WINDS WILL INCREASE OUT OF THE NW...BUT REMAIN UNDER 10 KTS.
ELSEWHERE...SHOWERS ARE BLOSSOMING ON THE RADAR ACRS THE FOOTHILLS
AT TIME OF 18Z TAF ISSUANCE...AND SOME OF THIS ACTIVITY HAS BEEN
REPORTED TO BE PRODUCING GRAUPEL. THE COVERAGE DOES SEEM TO WARRANT
A MENTION OF SHRA AT ALL SITES (EXCEPT KAVL). MOST OF THE ACTIVITY
IS STILL LIGHT...SO CONFIDENCE ON RESTRICTIONS IS TOO LOW TO ADD
MENTION ATTM. SO OVERALL...EXPECTING VFR CONDITIONS THRU THE PERIOD.
MEANWHILE...NW FLOW SNOW SHOWER ACTIVITY WILL CONTINUE ALONG THE
TN/NC BORDER. NOT EXPECTING THIS TO AFFECT KAVL...BUT THERE IS A
POSSIBILITY OF BRIEF CIG AND/OR VSBY RESTRICTIONS THIS AFTN OR EVE.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 87% HIGH 100% HIGH 100% HIGH 94%
KHKY HIGH 97% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 94% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...ARK/NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1145 AM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
REACHING THE THE EAST COAST LATE SUNDAY. HIGH PRESSURE WILL BRIEFLY
MOVE INTO THE AREA ON MONDAY AHEAD OF A LOW PRESSURE SYSTEM THAT
WILL DEVELOP OVER THE MID MISSISSIPPI RIVER VALLEY. THIS LOW IS
EXPECTED TO QUICKLY CROSS THE AREA ON WEDNESDAY WITH COLD HIGH
PRESSURE FILLING IN BEHIND IT ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM...THE AXIS OF THE MID-UPR VORT LOBE IS JUST ABOUT TO
EXIT THE SE CORNER OF THE CWFA. A NICE LITTLE SNOW BAND CONSOLIDATED
FROM THE LAURENS AREA...ENE THRU ROCK HILL AND INTO MONROE NC. THERE
HAVE BEEN A FEW REPORTS OF UP TO 1.5" OF SNOW ACCUM WITH THE BAND.
BUT ROADS SEEM TO BE STAYING WET. THE BAND LOOKS TO BE PICKING UP
SOME SPEED...AS IT SHIFTS TO THE SE...AND MAY BE LOSING SOME
INTENSITY. SO NOT EXPECTING ANY MAJOR IMPACTS WITH IT FOR THE REST
OF ITS TRACK THRU THE REMAINDER OF THE CWFA.
IN THE WAKE OF THE VORT LOBE...CLEARING HAS BEEN OCCURRING ACRS MUCH
OF THE BLUE RIDGE ESCARPMENT AND ADJACENT FOOTHILLS FROM NE GA UP
THRU WRN NC. THE INSOLATION IS QUICKLY DESTABILIZING THE BL...WITH
LAPS ALREADY SHOWING 100-150 J/KG OF CAPE AT 16Z. THE LTST RAP SEEMS
TO BE INITIALIZING BOTH THE QPF AND THE INSTBY THE BEST...AND IT
DOES HAVE UP TO 200-300 J/KG OF CAPE THIS AFTN ACRS THE PIEDMONT
WITH ENUF CONVERGENCE FOR SHWR DEVELOPMENT. THE MAIN LIMITING FACTOR
APPEARS TO BE THE MID AND UPR SUPPORT WILL BE LACKING. EVEN THE
NAM...WHICH INITIALIZES ANOTHER VORT MAX OVR ERN TN...DOES NOT
TRANSLATE THAT FEATURE INTO APPRECIABLE QG FORCING ACRS THE CWFA
THIS AFTN. SO I TRIMMED POPS BACK SLIGHTLY IN THE WEST...BUT OPTED
TO KEEP A HIGH-END CHC TO LIKELY POP IN THE EAST LATER FOR NOW (DUE
TO THE INSTBY AND HI-RES MODELS DEPICTING CONVECTION). THE UPSHOT IS
THAT THE WINTER WX ADV FOR THE SRN NC MTNS/NE GA AND SC MTNS CAN BE
CANCELLED. THE REST OF THE ADV LOOKS GOOD THRU 6 PM...GIVEN THE
CONVECTIVE TRENDS ON THE MRX RADAR.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...THE 12Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NE
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH MID MORNING AS
SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BETWEEN 12Z TO
18Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKEN THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS SUPPORTS
CEILINGS FALLING TO LVFR BETWEEN 12Z TO 15Z. THE ARRIVAL OF THE DEEP
FORCING AT DAY BREAK MAY YIELD ONE OF THE HIGHEST CHCS FOR PRECIP
DURING THE PERIOD. ANOTHER BAND OF RASN MAY PASS ACROSS THE TERMINAL
BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY SLOT. ONCE THE DRY SLOT
ARRIVES...CEILINGS WILL LIFT AND STEADY NW WINDS SHOULD REMAIN
THROUGH 12Z SUN. I WOULD EXPECT THAT ACCUMULATING SNOW IS POSSIBLE
THIS MORNING AND AGAIN LATE THIS AFTERNOON...ACCUMS WILL LIKELY
REMAIN LESS THAN A HALF INCH.
ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE WINDOWS OF MVFR CEILINGS DEVELOP BETWEEN 12 TO 15Z...BUT
DOWNSLOPE FLOW SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE
THE POTENTIAL FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC
BETWEEN 12Z TO 16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE
BAND THIS AFTERNOON WILL NEED CLOSE ATTENTION.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
16-22Z 22-04Z 04-10Z 10-16Z
KCLT HIGH 84% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 91% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 89% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...ARK/NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
957 AM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
TODAY. LOW PRESSURE WILL MOVE OFF THE EAST COAST ON SUNDAY...WITH A
RETURN OF BRIEF HIGH PRESSURE THROUGH MONDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE MID MISSISSIPPI RIVER VALLEY ON TUESDAY WILL
CROSS THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM...AS THE CENTER OF A COMPACT 500 MB LOW CROSSES THE
CWFA THIS MORNING...PRECIP BANDS HAVE EXPANDED TO ITS EAST ACRS THE
SRN NC PIEDMONT AND MUCH OF THE UPSTATE. I BUMPED UP THE POPS TO
LIKELY IN THESE AREAS. AS THE PRECIP RATES INCREASE...RAIN HAS BEEN
MIXING WITH AND CHANGING OVER TO SNOW. A FEW BANDS HAVE BECOME
SOMEWHAT INTENSE IN THE CHARLOTTE METRO AREA. FORTUNATELY...GROUND
TEMPS ARE WARM...AND THE BANDS ARE SMALL AND TRANSITORY. A LOOK AT
AREA WEBCAMS SHOW SNOW STILL NOT STICKING IN MOST SPOTS. SO WILL
HANDLE THIS WITH AN SPS...RATHER THAN A WSW. AS FOR THE CURRENT
WSW...THAT AREA IS IN THE NVA SIDE OF THE VORTMAX...AND CLEARING IS
REALLY EXPANDING ON VIS SAT IMAGERY. I WILL ENTERTAIN CUTTING THE
WINTER WX ADV BACK WITH THE NEXT UPDATE GIVEN TRENDS.
ONE REASON I DID NOT WITH THIS UPDATE WAS THAT HIGH RES MODELS STILL
IN AGREEMENT ON ENUF CONVECTIVE INSTBY FOR SHOWERS TO DEVELOP ALONG
THE BLUE RIDGE...WITH ENUF CONVERGENCE TO HOLD TOGETHER AS THEY
TRACK E/SE ACRS THE PIEDMONT THIS AFTN. THE CLEARING WILL HELP WITH
DESTABILIZATION...BUT WILL ALSO WARM THE BL. SO THERE IS UNCERTAINTY
ON HOW MUCH OF THE PRECIP WILL FALL AS SNOW...EVEN IN SOME OF THE
HIGHER ELEVATIONS OF THE SRN NC MTNS AND THE GA/SC MTNS. I WILL
REASSESS THE GUIDANCE AND TRENDS AND MAKE A DECISION WITH THE NEXT
UPDATE BEFORE NOON.
PREVIOUS DISCUSSION...
AS OF 345 AM...LATEST IR SATELLITE INDICATES COLD TOP CLOUDS RAPIDLY
EXPANDING ACROSS THE SOUTHERN AND CENTRAL NC MTNS...WITH A BAND OF
-22C OR COLDER CLOUDS ACROSS EXTREME NE GA AND THE SC MTNS. RADAR
RETURNS HAVE INCREASED EARLY THIS MORNING...ESPECIALLY ACROSS NE
GA...SC MTNS...AND THE CENTRAL MOUNTAINS...WITH SEVERAL AREAS OF DBZ
AROUND 30 DBZ. DUAL POL PRODUCTS INDICATE THAT THE MELTING LAYER HAS
LOWERED TO AROUND 1 KFT. BASED ON THE LATEST TRENDS...I WILL ADD THE
CENTRAL NC MTNS FROM MACON TO TRANSYLVANIA...EXTREME NE GA FROM
FRANKLIN TO RABUN...AND OCONEE AND PICKENS MTNS TO THE WINTER
WEATHER ADVISORY UNTIL 6 PM.
SHOWERS ARE FORECAST TO SPREAD SLOWLY EAST ACROSS THE FOOTHILLS AND
PIEDMONT THIS MORNING. THE EASTWARD MOVEMENT OF THE PRECIPITATION
WILL BE A RESULT OF THE SPREADING OF H5 15 TO 20 MB/HR VERTICAL
VELOCITIES ALONG AND AHEAD OF THE CLOSED LOW. THE SYNOPTIC SCALE
FORCING SHOULD PEAK AROUND 12Z...THEN GRADUALLY WEAKENING THROUGH
THE REST OF THE DAYLIGHT HOURS. FORECAST SOUNDINGS ACROSS THE
FOOTHILLS AND PIEDMONT...INCLUDING PARTIAL THICKNESSES...SHOULD
SUPPORT SN ACROSS THE MTNS...RASN ACROSS THE FOOTHILLS...WITH RA
ACROSS THE PIEDMONT. HOWEVER...STRONGER SHOWERS SHOULD RESULT IN
PURE SN THIS MORNING...EVEN OVER THE PIEDMONT. BASED ON A BLEND OF
HPC...WRFARW...AND RUC QPF...I WILL FORECAST 2-3 INCHES ACROSS THE
TN BORDER CO...AND THE SOUTHERN AND CENTRAL MTNS...WITH 4 INCHES
POSSIBLE IN SPOTS ALONG THE RIDGELINE OF THE SMOKIES. EXTREME NE GA
MAY SEE 0.5 TO 1.4 INCHES...WITH ACROSS AN INCH ACROSS OCONEE AND
PICKENS MTNS. AREAS EAST...INCLUDING THE GSP AND CLT METRO AREAS MAY
SEE AROUND 0.1-0.2 INCHES. HIGH TEMPERATURES ARE FORECAST TO RANGE
FROM THE 30S ACROSS THE MTNS TO THE LOW TO MID 40S EAST.
LATE THIS AFTERNOON...SREF INDICATES THAT MUCAPE WILL LIKELY POOL TO
AT LEAST 50 J/KG ACROSS THE FOOTHILLS AND PIEDMONT. AS THE H5 TROF
AXIS PIVOTS EAST OF THE MTNS. WEAKLY CONVECTIVE SHOWERS ARE EXPECTED
TO DEVELOP ACROSS THE FOOTHILLS. CONVECTIVE ALLOWING GUIDANCE
INDICATES THAT THE SHOWERS MAINLY ORGANIZE INTO A LINE OR A CLUSTER.
I WILL TIME THE CONVECTION EAST ACROSS THE EASTERN HALF OF THE
FORECAST AREA THIS AFTERNOON...REACHING KGSP AT 19Z...AND CLT BY 22Z.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE 12Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NE
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH MID MORNING AS
SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BETWEEN 12Z TO
18Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKEN THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS SUPPORTS
CEILINGS FALLING TO LVFR BETWEEN 12Z TO 15Z. THE ARRIVAL OF THE DEEP
FORCING AT DAY BREAK MAY YIELD ONE OF THE HIGHEST CHCS FOR PRECIP
DURING THE PERIOD. ANOTHER BAND OF RASN MAY PASS ACROSS THE TERMINAL
BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY SLOT. ONCE THE DRY SLOT
ARRIVES...CEILINGS WILL LIFT AND STEADY NW WINDS SHOULD REMAIN
THROUGH 12Z SUN. I WOULD EXPECT THAT ACCUMULATING SNOW IS POSSIBLE
THIS MORNING AND AGAIN LATE THIS AFTERNOON...ACCUMS WILL LIKELY
REMAIN LESS THAN A HALF INCH.
ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE WINDOWS OF MVFR CEILINGS DEVELOP BETWEEN 12 TO 15Z...BUT
DOWNSLOPE FLOW SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE
THE POTENTIAL FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC
BETWEEN 12Z TO 16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE
BAND THIS AFTERNOON WILL NEED CLOSE ATTENTION.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 89% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 97% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 92% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ010-
017-018-026.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059-062>064.
SC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ001-
002-004.
&&
$$
SYNOPSIS...HG
NEAR TERM...ARK/NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
655 AM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
TODAY. LOW PRESSURE WILL MOVE OFF THE EAST COAST ON SUNDAY...WITH A
RETURN OF BRIEF HIGH PRESSURE THROUGH MONDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE MID MISSISSIPPI RIVER VALLEY ON TUESDAY WILL
CROSS THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM...RECENT RADAR RETURNS HAVE TRENDED HIGHER ACROSS THE
NC NRN PIEDMONT. I WILL UPDATE THE FORECAST TO ADJUST POP TRENDS TO
RECENT RADAR IMAGES AND SFC OBS. IN ADDITION...I WILL REDUCE THE
MENTION OF SN ACROSS THE FOOTHILLS AND PIEDMONT EARLY THIS
MORNING...MIXING TO SNOW LATER THIS MORNING.
AS OF 345 AM...LATEST IR SATELLITE INDICATES COLD TOP CLOUDS RAPIDLY
EXPANDING ACROSS THE SOUTHERN AND CENTRAL NC MTNS...WITH A BAND OF
-22C OR COLDER CLOUDS ACROSS EXTREME NE GA AND THE SC MTNS. RADAR
RETURNS HAVE INCREASED EARLY THIS MORNING...ESPECIALLY ACROSS NE
GA...SC MTNS...AND THE CENTRAL MOUNTAINS...WITH SEVERAL AREAS OF DBZ
AROUND 30 DBZ. DUAL POL PRODUCTS INDICATE THAT THE MELTING LAYER HAS
LOWERED TO AROUND 1 KFT. BASED ON THE LATEST TRENDS...I WILL ADD THE
CENTRAL NC MTNS FROM MACON TO TRANSYLVANIA...EXTREME NE GA FROM
FRANKLIN TO RABUN...AND OCONEE AND PICKENS MTNS TO THE WINTER
WEATHER ADVISORY UNTIL 6 PM.
SHOWERS ARE FORECAST TO SPREAD SLOWLY EAST ACROSS THE FOOTHILLS AND
PIEDMONT THIS MORNING. THE EASTWARD MOVEMENT OF THE PRECIPITATION
WILL BE A RESULT OF THE SPREADING OF H5 15 TO 20 MB/HR VERTICAL
VELOCITIES ALONG AND AHEAD OF THE CLOSED LOW. THE SYNOPTIC SCALE
FORCING SHOULD PEAK AROUND 12Z...THEN GRADUALLY WEAKENING THROUGH
THE REST OF THE DAYLIGHT HOURS. FORECAST SOUNDINGS ACROSS THE
FOOTHILLS AND PIEDMONT...INCLUDING PARTIAL THICKNESSES...SHOULD
SUPPORT SN ACROSS THE MTNS...RASN ACROSS THE FOOTHILLS...WITH RA
ACROSS THE PIEDMONT. HOWEVER...STRONGER SHOWERS SHOULD RESULT IN
PURE SN THIS MORNING...EVEN OVER THE PIEDMONT. BASED ON A BLEND OF
HPC...WRFARW...AND RUC QPF...I WILL FORECAST 2-3 INCHES ACROSS THE
TN BORDER CO...AND THE SOUTHERN AND CENTRAL MTNS...WITH 4 INCHES
POSSIBLE IN SPOTS ALONG THE RIDGELINE OF THE SMOKIES. EXTREME NE GA
MAY SEE 0.5 TO 1.4 INCHES...WITH ACROSS AN INCH ACROSS OCONEE AND
PICKENS MTNS. AREAS EAST...INCLUDING THE GSP AND CLT METRO AREAS MAY
SEE AROUND 0.1-0.2 INCHES. HIGH TEMPERATURES ARE FORECAST TO RANGE
FROM THE 30S ACROSS THE MTNS TO THE LOW TO MID 40S EAST.
LATE THIS AFTERNOON...SREF INDICATES THAT MUCAPE WILL LIKELY POOL TO
AT LEAST 50 J/KG ACROSS THE FOOTHILLS AND PIEDMONT. AS THE H5 TROF
AXIS PIVOTS EAST OF THE MTNS. WEAKLY CONVECTIVE SHOWERS ARE EXPECTED
TO DEVELOP ACROSS THE FOOTHILLS. CONVECTIVE ALLOWING GUIDANCE
INDICATES THAT THE SHOWERS MAINLY ORGANIZE INTO A LINE OR A CLUSTER.
I WILL TIME THE CONVECTION EAST ACROSS THE EASTERN HALF OF THE
FORECAST AREA THIS AFTERNOON...REACHING KGSP AT 19Z...AND CLT BY 22Z.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE 12Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NE
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH MID MORNING AS
SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BETWEEN 12Z TO
18Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKEN THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS SUPPORTS
CEILINGS FALLING TO LVFR BETWEEN 12Z TO 15Z. THE ARRIVAL OF THE DEEP
FORCING AT DAY BREAK MAY YIELD ONE OF THE HIGHEST CHCS FOR PRECIP
DURING THE PERIOD. ANOTHER BAND OF RASN MAY PASS ACROSS THE TERMINAL
BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY SLOT. ONCE THE DRY SLOT
ARRIVES...CEILINGS WILL LIFT AND STEADY NW WINDS SHOULD REMAIN
THROUGH 12Z SUN. I WOULD EXPECT THAT ACCUMULATING SNOW IS POSSIBLE
THIS MORNING AND AGAIN LATE THIS AFTERNOON...ACCUMS WILL LIKELY
REMAIN LESS THAN A HALF INCH.
ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE WINDOWS OF MVFR CEILINGS DEVELOP BETWEEN 12 TO 15Z...BUT
DOWNSLOPE FLOW SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE
THE POTENTIAL FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC
BETWEEN 12Z TO 16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE
BAND THIS AFTERNOON WILL NEED CLOSE ATTENTION.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
12-18Z 18-24Z 00-06Z 06-12Z
KCLT HIGH 87% HIGH 90% HIGH 100% HIGH 100%
KGSP HIGH 89% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 75% HIGH 98% HIGH 100% HIGH 100%
KHKY HIGH 83% HIGH 99% HIGH 100% HIGH 100%
KGMU HIGH 87% HIGH 98% HIGH 100% HIGH 100%
KAND HIGH 88% HIGH 99% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ010-
017-018-026.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059-062>064.
SC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ001-
002-004.
&&
$$
SYNOPSIS...HG
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
358 AM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
TODAY. LOW PRESSURE WILL MOVE OFF THE EAST COAST ON SUNDAY...WITH A
RETURN OF BRIEF HIGH PRESSURE THROUGH MONDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE MID MISSISSIPPI RIVER VALLEY ON TUESDAY WILL
CROSS THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 345 AM...LATEST IR SATELLITE INDICATES COLD TOP CLOUDS
RAPIDLY EXPANDING ACROSS THE SOUTHERN AND CENTRAL NC MTNS...WITH A
BAND OF -22C OR COLDER CLOUDS ACROSS EXTREME NE GA AND THE SC
MTNS. RADAR RETURNS HAVE INCREASED EARLY THIS MORNING...ESPECIALLY
ACROSS NE GA...SC MTNS...AND THE CENTRAL MOUNTAINS...WITH SEVERAL
AREAS OF DBZ AROUND 30 DBZ. DUAL POL PRODUCTS INDICATE THAT THE
MELTING LAYER HAS LOWERED TO AROUND 1 KFT. BASED ON THE LATEST
TRENDS...I WILL ADD THE CENTRAL NC MTNS FROM MACON TO
TRANSYLVANIA...EXTREME NE GA FROM FRANKLIN TO RABUN...AND OCONEE
AND PICKENS MTNS TO THE WINTER WEATHER ADVISORY UNTIL 6 PM.
SHOWERS ARE FORECAST TO SPREAD SLOWLY EAST ACROSS THE FOOTHILLS AND
PIEDMONT THIS MORNING. THE EASTWARD MOVEMENT OF THE PRECIPITATION
WILL BE A RESULT OF THE SPREADING OF H5 15 TO 20 MB/HR VERTICAL
VELOCITIES ALONG AND AHEAD OF THE CLOSED LOW. THE SYNOPTIC SCALE
FORCING SHOULD PEAK AROUND 12Z...THEN GRADUALLY WEAKENING THROUGH
THE REST OF THE DAYLIGHT HOURS. FORECAST SOUNDINGS ACROSS THE
FOOTHILLS AND PIEDMONT...INCLUDING PARTIAL THICKNESSES...SHOULD
SUPPORT SN ACROSS THE MTNS...RASN ACROSS THE FOOTHILLS...WITH RA
ACROSS THE PIEDMONT. HOWEVER...STRONGER SHOWERS SHOULD RESULT IN
PURE SN THIS MORNING...EVEN OVER THE PIEDMONT. BASED ON A BLEND OF
HPC...WRFARW...AND RUC QPF...I WILL FORECAST 2-3 INCHES ACROSS THE
TN BORDER CO...AND THE SOUTHERN AND CENTRAL MTNS...WITH 4 INCHES
POSSIBLE IN SPOTS ALONG THE RIDGELINE OF THE SMOKIES. EXTREME NE GA
MAY SEE 0.5 TO 1.4 INCHES...WITH ACROSS AN INCH ACROSS OCONEE AND
PICKENS MTNS. AREAS EAST...INCLUDING THE GSP AND CLT METRO AREAS MAY
SEE AROUND 0.1-0.2 INCHES. HIGH TEMPERATURES ARE FORECAST TO RANGE
FROM THE 30S ACROSS THE MTNS TO THE LOW TO MID 40S EAST.
LATE THIS AFTERNOON...SREF INDICATES THAT MUCAPE WILL LIKELY POOL TO
AT LEAST 50 J/KG ACROSS THE FOOTHILLS AND PIEDMONT. AS THE H5 TROF
AXIS PIVOTS EAST OF THE MTNS. WEAKLY CONVECTIVE SHOWERS ARE EXPECTED
TO DEVELOP ACROSS THE FOOTHILLS. CONVECTIVE ALLOWING GUIDANCE
INDICATES THAT THE SHOWERS MAINLY ORGANIZE INTO A LINE OR A CLUSTER.
I WILL TIME THE CONVECTION EAST ACROSS THE EASTERN HALF OF THE
FORECAST AREA THIS AFTERNOON...REACHING KGSP AT 19Z...AND CLT BY 22Z.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE 6Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NW
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH THE PRE DAWN
HOURS AS SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BY
12Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKENING THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS
SUPPORTS CEILINGS FALLING TO AT LEAST MVFR BY 12Z...THEN LIFTING
ABOVE 030 BY 22Z. THE ARRIVAL OF THE DEEP FORCING AT DAY BREAK MAY
YIELD ONE OF THE HIGHEST CHCS FOR PRECIP DURING THE PERIOD. I WILL
HIGHLIGHT -SHSN BETWEEN 12Z TO 15Z. ANOTHER BAND OF RASN MAY PASS
ACROSS THE TERMINAL BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY
SLOT. ONCE THE DRY SLOT ARRIVES...CEILINGS WILL LIFT AND STEADY NW
WINDS SHOULD REMAIN THROUGH 12Z SUN. I WOULD EXPECT THAT
ACCUMULATING SNOW IS POSSIBLE THIS MORNING AND AGAIN LATE THIS
AFTERNOON...ACCUMS WILL LIKELY REMAIN LESS THAN A HALF INCH.
ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE MVFR CEILINGS DEVELOP AROUND 11Z...BUT DOWNSLOPE FLOW
SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE THE POTENTIAL
FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC BETWEEN 12Z TO
16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE BAND THIS
AFTERNOON WILL NEED CLOSE ATTENTION.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 86% HIGH 80% HIGH 94% HIGH 100%
KGSP HIGH 83% HIGH 95% HIGH 94% HIGH 100%
KAVL HIGH 84% HIGH 97% HIGH 100% HIGH 90%
KHKY HIGH 84% HIGH 91% HIGH 100% HIGH 100%
KGMU HIGH 81% MED 68% HIGH 95% HIGH 100%
KAND HIGH 87% MED 78% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ010-
017-018-026.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059-062>064.
SC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ001-
002-004.
&&
$$
SYNOPSIS...HG
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
350 AM EST SAT MAR 2 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE REGION FROM THE WEST
TODAY. LOW PRESSURE WILL MOVE OFF THE EAST COAST ON SUNDAY...WITH A
RETURN OF BRIEF HIGH PRESSURE THROUGH MONDAY. A LOW PRESSURE SYSTEM
DEVELOPING OVER THE MID MISSISSIPPI RIVER VALLEY ON TUESDAY WILL
CROSS THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM...LATEST IR SATELLITE INDICATES COLD TOP CLOUDS RAPIDLY
EXPANDING ACROSS THE SOUTHERN AND CENTRAL NC MTNS...WITH A BAND OF
-22C OR COLDER CLOUDS ACROSS EXTREME NE GA AND THE SC MTNS. RADAR
RETURNS HAVE INCREASED EARLY THIS MORNING...ESPECIALLY ACROSS NE
GA...SC MTNS...AND THE CENTRAL MOUNTAINS...WITH SEVERAL AREAS OF DBZ
AROUND 30 DBZ. DUAL POL PRODUCTS INDICATE THAT THE MELTING LAYER HAS
LOWERED TO AROUND 1 KFT. BASED ON THE LATEST TRENDS...I WILL ADD THE
CENTRAL NC MTNS FROM MACON TO TRANSYLVANIA...EXTREME NE GA FROM
FRANKLIN TO RABUN...AND OCONEE AND PICKENS MTNS TO THE WINTER
WEATHER ADVISORY UNTIL 6 PM.
SHOWERS ARE FORECAST TO SPREAD SLOWLY EAST ACROSS THE FOOTHILLS AND
PIEDMONT THIS MORNING. THE EASTWARD MOVEMENT OF THE PRECIPITATION
WILL BE A RESULT OF THE SPREADING OF H5 15 TO 20 MB/HR VERTICAL
VELOCITIES ALONG AND AHEAD OF THE CLOSED LOW. THE SYNOPTIC SCALE
FORCING SHOULD PEAK AROUND 12Z...THEN GRADUALLY WEAKENING THROUGH
THE REST OF THE DAYLIGHT HOURS. FORECAST SOUNDINGS ACROSS THE
FOOTHILLS AND PIEDMONT...INCLUDING PARTIAL THICKNESSES...SHOULD
SUPPORT SN ACROSS THE MTNS...RASN ACROSS THE FOOTHILLS...WITH RA
ACROSS THE PIEDMONT. HOWEVER...STRONGER SHOWERS SHOULD RESULT IN
PURE SN THIS MORNING...EVEN OVER THE PIEDMONT. BASED ON A BLEND OF
HPC...WRFARW...AND RUC QPF...I WILL FORECAST 2-3 INCHES ACROSS THE
TN BORDER CO...AND THE SOUTHERN AND CENTRAL MTNS...WITH 4 INCHES
POSSIBLE IN SPOTS ALONG THE RIDGELINE OF THE SMOKIES. EXTREME NE GA
MAY SEE 0.5 TO 1.4 INCHES...WITH ACROSS AN INCH ACROSS OCONEE AND
PICKENS MTNS. AREAS EAST...INCLUDING THE GSP AND CLT METRO AREAS MAY
SEE AROUND 0.1-0.2 INCHES. HIGH TEMPERATURES ARE FORECAST TO RANGE
FROM THE 30S ACROSS THE MTNS TO THE LOW TO MID 40S EAST.
TONIGHT...NWFS WILL GRADUALLY FADE ALONG THE TN BORDER THIS
EVENING...ENDING DURING THE LATE NIGHT HOURS. WINDS WILL REMAIN FROM
THE NW...RANGING FROM 5 TO 10 KTS. CLOUD COVER WILL DECREASE THROUGH
THE NIGHT...ESPECIALLY EAST OF THE MTNS. LOW TEMPERATURES SHOULD
RANGE FROM THE L20S ACROSS THE MTNS TO THE MID TO U20S EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM SATURDAY...ONE FINAL SHORTWAVE WILL DROP INTO THE EAST
COAST TROUGH AXIS ON SUNDAY BEFORE IT DEPARTS...BRINGING MAINLY
CHANNELED VORTICITY FROM THE WRN GREAT LAKES TO THE WRN CAROLINAS.
DEEP LAYER MOISTURE WILL BE ABSENT WITH THIS FEATURE...BUT LINGERING
LOW LEVEL NW UPSLOPE FLOW MOISTURE MAY PERMIT ISOLATED SNOW SHOWERS
TO LINGER ALONG THE TN BORDER INTO THE MORNING HOURS BEFORE DRYING
UP. CHILLY THICKNESSES...AND LINGERING PATCHY MID AND HIGH
CLOUDS...WILL KEEP TEMPERATURES SEVERAL CATEGORIES BELOW NORMAL.
A FLAT UPPER RIDGE WILL CROSS THE AREA MONDAY THROUGH MONDAY NIGHT.
PLENTY OF HIGH LEVEL CLOUDS SHOULD TOP THE RIDGE AXIS IN THE SWIFT
WESTERLY FLOW ALOFT DURING THIS PERIOD. THE AIRMASS SHOULD MODIFY
ENOUGH TO PUSH MAX TEMPERATURES BACK INTO THE 50S THROUGHOUT MON
AFTN...EXCEPT 40S ALONG THE HIGHER MOUNTAINS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 310 AM SATURDAY...THERE IS GENERALLY GOOD CONSENSUS AMONG THE
VARIOUS MODELS ON A DEEPENING LOW PRES SYSTEM MOVING SE THROUGH THE
MIDWEST ON TUE...CROSSING THE FORECAST AREA ON WED...THEN DEEPENING
FURTHER ALONG THE IMMEDIATE E COAST WED NIGHT. HOWEVER...DIFFERENCES
AMONG THE MODELS IN THE SFC LOW AND 850 MB LOW CENTER TRACKS WILL
PLAY A CRITICAL ROLE IN PRECIPITATION TYPE AND AMOUNT. THERE IS GOOD
AGREEMENT THAT ISENTROPIC LIFT AHEAD OF THE SYSTEM WILL RETURN TO
THE REGION LATE MON NIGHT...WITH THE BEST BELT OF UPGLIDE ACROSS THE
HEART OF THE AREA MIDDAY TUE. PROFILES SUPPORT MAINLY RAIN ON THE
WARM ADVECTION SIDE OF THE SYSTEM...BUT WITH FREEZING RAIN POSSIBLE
IN SPOTS AT ONSET...ESPECIALLY ACROSS THE NRN NC MOUNTAINS.
THICKNESSES SHOULD CRASH WED MORNING AS THE COLD LOW PRESSURE SYSTEM
TRANSITIONS TOWARD THE COAST. QG FORCING SHOULD BE PLENTIFUL JUST
AHEAD OF THE LOW TUE NIGHT AND WED MORNING...WITH SOME DEGREE OF
FRONTOGENESIS AND DEFORMATION ZONE FORCING TRAILING THE DEPARTING
LOW THROUGH THE PIEDMONT WED AFTN/EVENING. VERY STEEP LAPSE RATES
UNDER THE PASSING UPPER LOW SHOULD SUPPORT AT LEAST ISOLD TO SCT
THUNDERSTORMS/THUNDERSNOW AT TIMES. CONFIDENCE IS HIGHEST ON
SIGNIFICANT ACCUMULATING SNOW OVER THE MTNS AND ALSO NC FOOTHILL AND
PIEDMONT LOCATIONS ALONG AND NORTH OF INTERSTATE 40. MORE OF A
RAIN/SNOW MIX IS EXPECTED TOWARD THE INTERSTATE 85 CORRIDOR AND
POINTS SOUTH...BUT LIKELY ENDING AS SNOW SHOWERS. WILL CONTINUE THE
HWO MENTION FOR THIS POTENTIALLY SIGNIFICANT WINTER STORM SYSTEM.
A WARMER AND DRY RIDGE PATTERN WILL RETURN THU THROUGH FRI...WITH
TEMPERATURES SLOWLY REBOUNDING TO WITHIN 5 DEGREES OF NORMAL.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE 6Z TAF WILL BEGIN WITH VFR CONDITIONS AND A LIGHT NW
WIND. CEILING BASES SHOULD GRADUALLY LOWER THROUGH THE PRE DAWN
HOURS AS SYNOPTIC SCALE FORCING SPREADS ACROSS THE PIEDMONT. BY
12Z...MID LEVEL FORCING SHOULD PEAK ACROSS THE TERMINAL...THEN
WEAKENING THROUGH THE AFTERNOON HOURS. NAM FORECAST SOUNDINGS
SUPPORTS CEILINGS FALLING TO AT LEAST MVFR BY 12Z...THEN LIFTING
ABOVE 030 BY 22Z. THE ARRIVAL OF THE DEEP FORCING AT DAY BREAK MAY
YIELD ONE OF THE HIGHEST CHCS FOR PRECIP DURING THE PERIOD. I WILL
HIGHLIGHT -SHSN BETWEEN 12Z TO 15Z. ANOTHER BAND OF RASN MAY PASS
ACROSS THE TERMINAL BETWEEN 22Z TO 24Z WITH THE PUSH OF THE DRY
SLOT. ONCE THE DRY SLOT ARRIVES...CEILINGS WILL LIFT AND STEADY NW
WINDS SHOULD REMAIN THROUGH 12Z SUN. I WOULD EXPECT THAT
ACCUMULATING SNOW IS POSSIBLE THIS MORNING AND AGAIN LATE THIS
AFTERNOON...ACCUMS WILL LIKELY REMAIN LESS THAN A HALF INCH.
ELSEWHERE...TIMING SIMILAR TO CLT. HOWEVER...KGSP...KGMU...AND KHKY
SHOULD SEE MVFR CEILINGS DEVELOP AROUND 11Z...BUT DOWNSLOPE FLOW
SHOULD SUPPORT VFR BY MID MORNING. ALL AREAS WILL SEE THE POTENTIAL
FOR LIGHT ACCUMULATING SNOW THIS MORNING....BEST CHC BETWEEN 12Z TO
16Z. HOWEVER...THE FORMATION OF A WEAKLY CONVECTIVE BAND THIS
AFTERNOON WILL NEED CLOSE ATTENTION.
OUTLOOK...SNOW SHOWERS WILL DIMINSIHING THE TENNESSEE BORDER ON
SUNDAY. MONDAY SHOULD REMAIN VFR ACROSS THE FORECAST AREA.
ANOTHER LOW PRESSURE SYSTEM WILL SPREAD LLVL MOISTURE AND
PRECIPITATION ACROSS THE REGION TUESDAY AND WEDNESDAY MORNING.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 86% HIGH 80% HIGH 94% HIGH 100%
KGSP HIGH 83% HIGH 95% HIGH 94% HIGH 100%
KAVL HIGH 84% HIGH 97% HIGH 100% HIGH 90%
KHKY HIGH 84% HIGH 91% HIGH 100% HIGH 100%
KGMU HIGH 81% MED 68% HIGH 95% HIGH 100%
KAND HIGH 87% MED 78% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ010-
017-018-026.
NC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059-062>064.
SC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ001-
002-004.
&&
$$
SYNOPSIS...HG
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
651 PM CST SUN MAR 3 2013
.DISCUSSION.../ISSUED AT 651 PM CST/
LIGHT PRECIPITATION OR DRIZZLE HAS DEVELOPED ALONG THE ISENTROPIC
LIFT ACROSS THE NORTHEASTERN HALF OF THE FORECAST AREA THIS EVENING.
TEMPERATURES REMAIN RELATIVELY MILD WITH THE VAST MAJORITY OF OBS
STILL AT OR ABOVE FREEZING. MODELS HAVING QUITE A BIT OF DIFFICULTY
WITH THIS SYSTEM ESPECIALLY AT THE NEAR SURFACE. MUCH OF THE AREA
REMAINS QUITE DRY AT THE LOWER LEVELS WHICH IS NOT WELL HANDLED BY
ANY MODEL EXCEPT PERHAPS THE RAP. WITH THE LACK OF LOW LEVEL
MOISTURE AND THE MILDER SURFACE TEMPERATURES...PRECIPITATION HAS
BEEN VERY LIGHT OR DRIZZLY FOR THE MOST PART. THE HRRR AND RAP
SUGGEST THAT THE ISENTROPIC BAND WILL LIKELY LIFT NORTHEAST INTO THE
EARLY MORNING HOURS...KEEPING THE MORE ORGANIZED PRECIPITATION...AND
SNOWFALL POTENTIAL MAINLY ALONG AND EAST OF A BROOKINGS TO SPENCER
LINE OVERNIGHT. ELSEWHERE...VERY LIGHT RAIN...FREEZING RAIN OR
DRIZZLE IS EXPECTED INTO THE EARLY MORNING HOURS. IF WE CANNOT GET
MORE SIGNIFICANT LOW LEVEL MOISTURE/CLOUDS TO DEVELOP
OVERNIGHT...THE VAST MAJORITY OF THE CWA WILL SEE NO SNOW
DEVELOPMENT.
MADE SOME CHANGES MAINLY TO THE POPS AND PRECIPITATION TYPES. HAVE
DROPPED OFF THE POTENTIAL FOR MEASURABLE PRECIPITATION TO CHANCES OR
SLIGHT CHANGES AFTER MIDNIGHT FOR ALL BUT OUR FAR NORTHEASTERN
COUNTIES...WHICH IS CLOSER IN LINE WITH THE HRRR...RAP AND NAM.
PRECIPITATION TYPES WERE ADJUSTED TO KEEP IN LINE WITH THE WARMER
SURFACE AND LOW LEVEL TEMPERATURES. FOR AREAS OUTSIDE OF THE MORE
ORGANIZED ISENTROPIC LIFT ZONE...NEAR SOUTHWEST MINNESOTA...HAVE
LOWERED QPF...ICE ACCUMULATIONS AND SNOW AMOUNTS WITH MORE DRIZZLY
CONDITIONS BEING REPORTED. ALSO WARMED LOWS A BIT WITH MID AND HIGH
CLOUDS STICKING AROUND TONIGHT AND THE SOMEWHAT BREEZY SOUTHEAST
WINDS HOLDING ON THROUGH THE BULK OF THE NIGHT.
THE WINTER WEATHER ADVISORY REMAINS AS IS...BUT WILL BE REVISITING
THINGS LATER THIS EVENING. MAY POTENTIALLY NEED TO DROP SOME OF THE
WESTERN COUNTIES IF WE DO NOT SEE PRECIPITATION RATES OR LOW LEVEL
MOISTURE INCREASE THROUGH THE NEXT FEW HOURS.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
MODELS AGAIN ARE STRUGGLING MIGHTILY IN DEPICTION OF THE NEAR
SURFACE LAYER...EXHIBITING A VERY STRONG COLD AND HIGH RELATIVE
HUMIDITY BIAS. RAP HAS THE BEST HANDLE ON THIS...AND WOULD SUGGEST
LITTLE PRECIPITATION FOR TAF SITES BEYOND THE IMMEDIATE TERM...AND
THIS TYPE WOULD LIKELY REMAIN LIQUID WITH TEMPS ALOFT FOR TAF
SITES...WITH WET BULB PROCESS TO SNOW IN PRECIPITATION BAND LIFTING
NORTHEAST. AS TEMPERATURES DRY OUT ALOFT TONIGHT BEHIND THE MAIN
BAND...INDICATIONS ARE FOR SOME DEVELOPMENT OF IFR OR LIFR CEILINGS
ALONG WITH DRIZZLE/FREEZING DRIZZLE BY LATER TONIGHT AND INTO MONDAY
MORNING. BRIEF PERIOD WITH SOME MID LEVEL CLOUDINESS AS DIV Q
INCREASES LATER MORNING OR MIDDAY COULD YIELD ICE PROCESS
INTRODUCTION AND THREAT FOR A BRIEF PERIOD OF LIGHT SNOWFALL WITH
MVFR OR IFR VISIBILITY. BETTER THREAT FOR SNOWFALL FOR TAF SITES
LOOKS TO EXIST JUST BEYOND CURRENT FORECAST. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 302 PM CST/
ISENTROPIC LIFT ON THE 290 AND 295K SURFACES INCREASING RESULTING IN
SOME LIGHT RAIN ALONG A BAND FROM KHON-KFSD. AS ISENTROPIC LIFT
CONTINUES TO INCREASE...EXPECT BAND TO BECOME MORE ESTABLISHED INTO
THE EVENING HOURS. WARM YET DRY LAYER ALOFT NEAR 850 MB. AS
PRECIPITATION INTENSITY INCREASES...EXPECT LAYER TO EVAPORATIVELY
COOL LEADING TO THE POTENTIAL OF SNOW...HOWEVER...UPPER LEVELS BEGIN
TO DRY OUT FROM THE SOUTHWEST TO THE NORTHEAST MAKING IT DIFFICULT
TO GET ICE INTO THE COLUMN. FOR THIS EVENING...POTENTIAL FOR SOME
LIGHT RAIN/FREEZING RAIN ACROSS MUCH OF THE CWA. HAVE ISSUED WINTER
WEATHER ADVISORY FOR AREAS WHERE THERE IS A HIGHER CONFIDENCE FOR
LIGHT ICING POTENTIAL. WESTERN EDGE OF THE ADVISORY WAS DIFFICULT TO
DETERMINE...AND MAY NEED TO BE EXPANDED IF ICING BECOMES MORE
WIDESPREAD. ACROSS NORTHEAST CORNER OF FORECAST AREA...MAY SEE RAIN
CHANGE OVER TO SNOW THROUGH THE EVENING HOURS WITH A FEW INCHES OF
ACCUMULATION BEFORE THE ISENTROPIC LIFT DIES AWAY FROM WEST TO EAST
FROM 06-12Z MONDAY. MODELS INDICATE FAIR AMOUNT OF LOW LEVEL
SATURATION...AND MAY BE ABLE TO GET FREEZING DRIZZLE/DRIZZLE THROUGH
THE MORNING HOURS.
MAIN UPPER LEVEL WAVE APPROACHES FROM THE WEST NORTHWEST TOMORROW
AFTERNOON. WITH THE APPROACHING MAIN UPPER LEVEL WAVE...LIFT ONCE
AGAIN INCREASES ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST
AREA. FAIRLY SHARP BACK EDGE SHOULD DEVELOP BETWEEN AREAS THAT ARE
ABLE TO SATURATE ALOFT AND THOSE THAT DO NOT. EXPECT BAND OF
PRECIPITATION TO GRADUALLY SHIFT EAST THROUGH THE EVENING
HOURS...WITH WINDS INCREASING BEHIND THE COLD FRONT.
MONDAY NIGHT WILL SEE THE SYSTEM WRAP UP AND DROP THROUGH SOUTHWEST
MINNESOTA. WILL KEEP SOME FAIRLY HIGH POPS IN FOR THE NIGHT OVER THE
EASTERN THIRD OF THE CWA. BEST SNOWFALL SHOULD BE NORTH AND EAST OF
A BROOKINGS TO SPENCER IOWA LINE WHERE AN ADDITIONAL 1 TO 3 INCHES
WILL BE POSSIBLE. COLD AIR ALOFT SHOULD ELIMINATE ANY POTENTIAL FOR
MIXED PRECIPITATION AND THINKING ALL SNOW AT THIS POINT. THE OTHER
CONCERN ON MONDAY NIGHT WILL BE THE STRONG NORTHWEST WIND THAT
DEVELOPS. THE MODELS ARE IN PRETTY GOOD AGREEMENT SWINGING THROUGH
ABOUT 35 KNOTS TO 40 KNOTS AT 925MB ALONG WITH GOOD COLD AIR
ADVECTION SO WIND ADVISORY CRITERIA WILL LIKELY BE MET...ESPECIALLY
WEST OF INTERSTATE 29...MONDAY NIGHT INTO TUESDAY MORNING. WILL PUT
AN ADVISORY DOWN THE MISSOURI RIVER VALLEY CORRIDOR.
THE SNOW SHOULD BE WINDING DOWN TUESDAY MORNING WITH THE STRONG
NORTHWEST WINDS DEVELOPING ACROSS THE AREA. MAY BE SOME AREAS OF
BLOWING SNOW IN LOCATIONS THAT RECEIVE ENOUGH SNOWFALL...MAINLY
SOUTHWEST MINNESOTA. WITH SOME SNOW ON THE GROUND AND WINDY
CONDITIONS WILL WILL BE PRETTY COLD WITH HIGHS MAINLY IN THE LOWER
TO MIDDLE 20S...CLOSER TO 30 ALONG THE MISSOURI RIVER VALLEY WHERE
LITTLE TO NO SNOW IS EXPECTED.
TUESDAY NIGHT INTO WEDNESDAY HIGH PRESSURE WILL BUILD SOUTH INTO THE
AREA THEN SHIFT EAST WITH BREEZY CONDITIONS LIKELY WEDNESDAY
AFTERNOON IN CENTRAL SOUTH DAKOTA. LOWS IN THE MORNING WILL DROP
CLOSE TO ZERO ALONG THE HIGHWAY 14 CORRIDOR INTO SOUTHWEST MINNESOTA
WHILE CENTRAL SOUTH DAKOTA WILL BOTTOM OUT IN THE TEENS. HIGHS ON
WEDNESDAY WILL MODERATE BUT STILL 20 TO 25 IN SOUTHWEST MINNESOTA
AND AROUND 40 IN SOUTH CENTRAL SOUTH DAKOTA.
IN THE LATTER PERIODS(THU/SUN)...OVERALL FAIRLY MILD THROUGH THE
PERIOD AS A TROUGH OF LOW PRESSURE BUILDS OVER THE WESTERN UNITED
STATES. THIS WILL SPREAD A RIDGE OF HIGH PRESSURE ACROSS THE CENTRAL
UNITED STATES. THE MODELS CONTINUE TO SLOW THE PROGRESSION OF THIS
TROUGH AND HAVE VERY LITTLE CONSISTENCY SO NO REAL CONFIDENCE JUST
YET. REGARDLESS...ABOVE NORMAL TEMPERATURES MOST LOCATIONS THAT DO
NOT RECEIVE MUCH NEW SNOW WITH NORMAL TO A BIT BELOW NORMAL IN AREAS
WITH DEEPER SNOWCOVER. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR SDZ038-039-053>055-061-062-066-067-071.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR SDZ050-
052-057>060-063>065-068>071.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR SDZ040-056.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR MNZ071-072-080-081-089-090-097.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR IAZ001-012-013-020>022-031-032.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR IAZ031.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR IAZ002-003-014.
NE...WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR NEZ013-
014.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
600 PM CST SUN MAR 3 2013
.DISCUSSION.../ISSUED AT 302 PM CST/
ISENTROPIC LIFT ON THE 290 AND 295K SURFACES INCREASING RESULTING IN
SOME LIGHT RAIN ALONG A BAND FROM KHON-KFSD. AS ISENTROPIC LIFT
CONTINUES TO INCREASE...EXPECT BAND TO BECOME MORE ESTABLISHED INTO
THE EVENING HOURS. WARM YET DRY LAYER ALOFT NEAR 850 MB. AS
PRECIPITATION INTENSITY INCREASES...EXPECT LAYER TO EVAPORATIVELY
COOL LEADING TO THE POTENTIAL OF SNOW...HOWEVER...UPPER LEVELS BEGIN
TO DRY OUT FROM THE SOUTHWEST TO THE NORTHEAST MAKING IT DIFFICULT
TO GET ICE INTO THE COLUMN. FOR THIS EVENING...POTENTIAL FOR SOME
LIGHT RAIN/FREEZING RAIN ACROSS MUCH OF THE CWA. HAVE ISSUED WINTER
WEATHER ADVISORY FOR AREAS WHERE THERE IS A HIGHER CONFIDENCE FOR
LIGHT ICING POTENTIAL. WESTERN EDGE OF THE ADVISORY WAS DIFFICULT TO
DETERMINE...AND MAY NEED TO BE EXPANDED IF ICING BECOMES MORE
WIDESPREAD. ACROSS NORTHEAST CORNER OF FORECAST AREA...MAY SEE RAIN
CHANGE OVER TO SNOW THROUGH THE EVENING HOURS WITH A FEW INCHES OF
ACCUMULATION BEFORE THE ISENTROPIC LIFT DIES AWAY FROM WEST TO EAST
FROM 06-12Z MONDAY. MODELS INDICATE FAIR AMOUNT OF LOW LEVEL
SATURATION...AND MAY BE ABLE TO GET FREEZING DRIZZLE/DRIZZLE THROUGH
THE MORNING HOURS.
MAIN UPPER LEVEL WAVE APPROACHES FROM THE WEST NORTHWEST TOMORROW
AFTERNOON. WITH THE APPROACHING MAIN UPPER LEVEL WAVE...LIFT ONCE
AGAIN INCREASES ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST
AREA. FAIRLY SHARP BACK EDGE SHOULD DEVELOP BETWEEN AREAS THAT ARE
ABLE TO SATURATE ALOFT AND THOSE THAT DO NOT. EXPECT BAND OF
PRECIPITATION TO GRADUALLY SHIFT EAST THROUGH THE EVENING
HOURS...WITH WINDS INCREASING BEHIND THE COLD FRONT.
MONDAY NIGHT WILL SEE THE SYSTEM WRAP UP AND DROP THROUGH SOUTHWEST
MINNESOTA. WILL KEEP SOME FAIRLY HIGH POPS IN FOR THE NIGHT OVER THE
EASTERN THIRD OF THE CWA. BEST SNOWFALL SHOULD BE NORTH AND EAST OF
A BROOKINGS TO SPENCER IOWA LINE WHERE AN ADDITIONAL 1 TO 3 INCHES
WILL BE POSSIBLE. COLD AIR ALOFT SHOULD ELIMINATE ANY POTENTIAL FOR
MIXED PRECIPITATION AND THINKING ALL SNOW AT THIS POINT. THE OTHER
CONCERN ON MONDAY NIGHT WILL BE THE STRONG NORTHWEST WIND THAT
DEVELOPS. THE MODELS ARE IN PRETTY GOOD AGREEMENT SWINGING THROUGH
ABOUT 35 KNOTS TO 40 KNOTS AT 925MB ALONG WITH GOOD COLD AIR
ADVECTION SO WIND ADVISORY CRITERIA WILL LIKELY BE MET...ESPECIALLY
WEST OF INTERSTATE 29...MONDAY NIGHT INTO TUESDAY MORNING. WILL PUT
AN ADVISORY DOWN THE MISSOURI RIVER VALLEY CORRIDOR.
THE SNOW SHOULD BE WINDING DOWN TUESDAY MORNING WITH THE STRONG
NORTHWEST WINDS DEVELOPING ACROSS THE AREA. MAY BE SOME AREAS OF
BLOWING SNOW IN LOCATIONS THAT RECEIVE ENOUGH SNOWFALL...MAINLY
SOUTHWEST MINNESOTA. WITH SOME SNOW ON THE GROUND AND WINDY
CONDITIONS WILL WILL BE PRETTY COLD WITH HIGHS MAINLY IN THE LOWER
TO MIDDLE 20S...CLOSER TO 30 ALONG THE MISSOURI RIVER VALLEY WHERE
LITTLE TO NO SNOW IS EXPECTED.
TUESDAY NIGHT INTO WEDNESDAY HIGH PRESSURE WILL BUILD SOUTH INTO THE
AREA THEN SHIFT EAST WITH BREEZY CONDITIONS LIKELY WEDNESDAY
AFTERNOON IN CENTRAL SOUTH DAKOTA. LOWS IN THE MORNING WILL DROP
CLOSE TO ZERO ALONG THE HIGHWAY 14 CORRIDOR INTO SOUTHWEST MINNESOTA
WHILE CENTRAL SOUTH DAKOTA WILL BOTTOM OUT IN THE TEENS. HIGHS ON
WEDNESDAY WILL MODERATE BUT STILL 20 TO 25 IN SOUTHWEST MINNESOTA
AND AROUND 40 IN SOUTH CENTRAL SOUTH DAKOTA.
IN THE LATTER PERIODS(THU/SUN)...OVERALL FAIRLY MILD THROUGH THE
PERIOD AS A TROUGH OF LOW PRESSURE BUILDS OVER THE WESTERN UNITED
STATES. THIS WILL SPREAD A RIDGE OF HIGH PRESSURE ACROSS THE CENTRAL
UNITED STATES. THE MODELS CONTINUE TO SLOW THE PROGRESSION OF THIS
TROUGH AND HAVE VERY LITTLE CONSISTENCY SO NO REAL CONFIDENCE JUST
YET. REGARDLESS...ABOVE NORMAL TEMPERATURES MOST LOCATIONS THAT DO
NOT RECEIVE MUCH NEW SNOW WITH NORMAL TO A BIT BELOW NORMAL IN AREAS
WITH DEEPER SNOWCOVER. /08
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
MODELS AGAIN ARE STRUGGLING MIGHTILY IN DEPICTION OF THE NEAR
SURFACE LAYER...EXHIBITING A VERY STRONG COLD AND HIGH RELATIVE
HUMIDITY BIAS. RAP HAS THE BEST HANDLE ON THIS...AND WOULD SUGGEST
LITTLE PRECIPITATION FOR TAF SITES BEYOND THE IMMEDIATE TERM...AND
THIS TYPE WOULD LIKELY REMAIN LIQUID WITH TEMPS ALOFT FOR TAF
SITES...WITH WET BULB PROCESS TO SNOW IN PRECIPITATION BAND LIFTING
NORTHEAST. AS TEMPERATURES DRY OUT ALOFT TONIGHT BEHIND THE MAIN
BAND...INDICATIONS ARE FOR SOME DEVELOPMENT OF IFR OR LIFR CEILINGS
ALONG WITH DRIZZLE/FREEZING DRIZZLE BY LATER TONIGHT AND INTO MONDAY
MORNING. BRIEF PERIOD WITH SOME MID LEVEL CLOUDINESS AS DIV Q
INCREASES LATER MORNING OR MIDDAY COULD YIELD ICE PROCESS
INTRODUCTION AND THREAT FOR A BRIEF PERIOD OF LIGHT SNOWFALL WITH
MVFR OR IFR VISIBILITY. BETTER THREAT FOR SNOWFALL FOR TAF SITES
LOOKS TO EXIST JUST BEYOND CURRENT FORECAST. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR SDZ038-039-053>055-061-062-066-067-071.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR SDZ050-
052-057>060-063>065-068>071.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR SDZ040-056.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR MNZ071-072-080-081-089-090-097.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR IAZ001-012-013-020>022-031-032.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR IAZ031.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR IAZ002-003-014.
NE...WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR NEZ013-
014.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1105 AM CST SAT MAR 2 2013
.DISCUSSION...
OVERALL...FORECAST IN GOOD SHAPE THIS MORNING. STRATUS ACROSS THE
JAMES RIVER VALLEY PRODUCING A FEW FLURRIES...BUT DRY SUB CLOUD
LAYER ABSORBING PRECIPITATION BEFORE IT REACHES THE SURFACE. GOING
FORECAST HIGHS LOOK REASONABLE...BUT HAVE RAISED FORECAST HIGHS A
FEW DEGREES ACROSS CENTRAL SOUTH DAKOTA WITH APPROACHING WARM FRONT.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAYLIGHT HOURS WITH
SOUTHERLY WINDS AROUND 10 KNOTS. MODELS DEPICT LOW LEVEL SATURATION
INCREASING ACROSS THE REGION THIS EVENING IN ADVANCE OF NEXT WAVE TO
IMPACT THE REGION ON SUNDAY. WILL LIKELY BE DIFFICULT TO SCOUR OUT
LOW LEVEL CLOUD ON SUNDAY WITH INCREASING EASTERLY FLOW.
&&
.PREV DISCUSSION.../ISSUED AT 400 AM CST/
NEAR TERM CHALLENGE IS THE LAST REMNANTS OF SOME STRATUS NOSING UP
INTO PARTS OF NORTHWEST IA...ALONG AND JUST EAST OF THE BIG SIOUX
RIVER AT THIS TIME. SITUATED NEAR 925MB...IT IS SLOWLY EDGING
SOUTHWARD AND SHOULD CONTINUE TO PROCEED IN THAT DIRECTION THROUGH
15Z THIS MORNING. AT THAT TIME...BOTH THE NAM12 AND RAP ARE IN GOOD
AGREEMENT IN SHIFTING THE 925MB WINDS FROM THE NORTH/NORTHWEST TO
THE SOUTH BETWEEN 15Z AND 18Z. THEREFORE IF ANY STRATUS IS STILL IN
OUR FAR SOUTHEAST ZONES AT 15Z...IT MAY HAVE TROUBLE LEAVING THAT
AREA UNLESS IT MIXES OUT SOME. OTHERWISE...MID AND HIGH LEVEL CLOUDS
WILL INCREASE TODAY GIVING A PARTLY SUNNY TO MOSTLY CLOUDY SKY
OVERALL. SURFACE RIDGING IS MOVING EASTWARD AT THIS TIME ACROSS OUR
FORECAST AREA WHICH WILL SHIFT THE SURFACE WINDS TO THE SOUTH. GIVEN
THE NAM AND GFS 925MB TEMPERATURES...ANOTHER SEASONALLY COOL DAY
WILL BE IN STORE FOR AREAS ALONG AND EAST OF I 29. HOWEVER OUR
CENTRAL SD ZONES SHOULD WARM INTO THE LOWER AND MID 40S.
NO CHANGES REALLY NEEDED FOR THE TONIGHT PERIOD...WITH A SOUTHEAST
BREEZE STAYING BRISK. THEREFORE NOT ANTICIPATING TEMPERATURES
FALLING OFF ALL THAT MUCH. DUE TO THE BREEZE...WE MAY BE A BIT TOO
COOL WITH THE LOWS TONIGHT SO THAT IS SOMETHING TO WATCH FOR.
ON SUNDAY...WELL ADVERTISED UPPER WAVE BEGINS TO MOVE INTO THE IDAHO
AND WESTERN MT REGION. AHEAD OF IT...SURFACE LOW PRESSURE FORMS IN A
NORTH TO SOUTH ELONGATION ALONG THE FRONT RANGE OF THE ROCKIES. THE
NORTHERN PORTION OF THE LOW THEN EXTENDS A DECENT WARM FRONT
SOUTHEASTWARD INTO THE CENTRAL PLAINS. TO THE NORTH OF THE WARM
FRONT...INDICATIONS ARE INCREASING THAT THERE MAY BE ENOUGH
SATURATION AND ISENTROPIC LIFT TO PRODUCE SOME LIGHT
PRECIPITATION...WITH THE TYPE DEPENDING ON SURFACE TO 850MB
TEMPERATURES. THE MOST CONCERN AT THIS TIME IS IN AN AREA FROM
EASTERN KINGSBURY AND WESTERN BROOKINGS COUNTIES...WHERE THERE COULD
BE SOME LIGHT FREEZING RAIN. RIGHT NOW...HAVE VERY MINIMAL
ACCUMULATIONS OF ICE IN THOSE AREAS BECAUSE SURFACE TEMPERATURES
SHOULD WARM INTO THE LOWER 30S DURING THE AFTERNOON. BUT WILL LIKELY
MENTION THIS POSSIBILITY IN THE FORTH COMING HWO. CLOSER TO THE WARM
FRONT...TEMPERATURES WILL BE QUITE MILD IN OUR CENTRAL SD ZONES...
WITH 40S WIDESPREAD IN THOSE AREAS. CONVERSELY IN OUR NORTHEAST
ZONES...LOWER 30S IS LIKELY ALL THE WARMING THEY WILL GET.
FOR THE REST OF THE FORECAST SUNDAY NIGHT THROUGH MONDAY NIGHT...
FOLLOWED A BLEND OF THE 00Z GFS/00Z GEM GLOBAL AND 12Z ECMWF. THE
NAM LOOKS TO BE A NORTHERN OUTLIER AT THIS TIME AS IT SO OFTEN IS
WITH SYSTEMS IN THE NORTHERN JET STREAM MOVING OUT OF THE NORTHERN
ROCKIES. THAT SAID...THE 00Z ECMWF DID ALSO TREND A BIT FURTHER
NORTHWARD WITH THE STORM TRACK COMPARED WITH ITS 12Z COUNTERPART.
HAVE NOTICED THE LAST COUPLE OF DAYS THAT THE ECMWF IS BATTLING
ITSELF WITH THE 00Z RUNS FURTHER NORTH THEN THE 12Z RUNS WHICH IS
INTERESTING.
ON SUNDAY NIGHT...MOST OF THE PRECIPITATION WILL STILL LIKELY LIE
NEAR THE 850MB BAROCLINIC ZONE CLOSE TO THE AFOREMENTIONED WARM
FRONT. BROAD LIFT IS PRETTY STRONG IN OUR NORTHERN AND EASTERN ZONES
ALL NIGHT. AND WITH TEMPERATURES COOLING ALOFT TO SUB ZERO...AGAIN
USING THE ABOVE MENTIONED MODEL BLEND...SNOW WILL BE LIKELY FOR
AREAS NORTH OF OUR MISSOURI RIVER VALLEY COUNTIES. AT THIS TIME...
IT APPEARS UPWARDS OF 3 TO 3.5 INCHES COULD FALL IN AN AXIS FROM
FROM AROUND BROOKINGS...TO WORTHINGTON...TO SPENCER IOWA. LIGHTER
AMOUNTS WILL THEN FOLLOW SUIT ON BOTH SIDES OF THAT AXIS BUT ANY
DEVIATION IN THE STORM TRACK COULD REALLY FOUL UP THIS THINKING. LOW
TEMPERATURES WILL AGAIN NOT LIKELY FALL TOO MUCH FROM DAYTIME
HIGHS...WITH A LOT OF 20S ANTICIPATED. BECAUSE OF TEMPERATURES BELOW
FREEZING COUPLED WITH WARM TEMPERATURES ALOFT...EVEN ON THE SOUTHERN
TRACK SOLUTIONS...AM A BIT CONCERNED ABOUT MORE LIGHT FREEZING RAIN
POTENTIAL LATE SUNDAY NIGHT IN AN AREA FROM CHAMBERLAIN TO LAKE
ANDES.
THEN ON MONDAY AND MONDAY NIGHT...THE AFOREMENTIONED MODEL BLEND
DIVES THE UPPER LOW SOUTHEASTWARD TOWARD TOPEKA KS/KANSAS CITY AREA
BY 12Z TUESDAY. THIS TRACK WOULD BE FAVORABLE FOR GIVING THE
NORTHEAST HALF OF OUR FORECAST AREA ACCUMULATING SNOW EITHER IN THE
ADVISORY OR WARNING CRITERIA CATEGORIES. GFS UPPER QG FORCING IS
MAXIMIZED IN A TRACK JUST SOUTH OF OUR MISSOURI RIVER VALLEY ZONES
WITH STRONG PV FORCING FOLLOWING SUIT. NOW ONE THING TO MENTION...IS
IT IS DIFFICULT TO TELL AT THIS POINT WHERE ANY MESOSCALE TO
MICROSCALE FRONTAL BANDING WILL TAKE PLACE OR ANY POTENTIAL UPPER
INSTABILITY. THE GLOBAL TYPE MODELS HAVE A TENDENCY TO WASH OUT
THESE FEATURES OUT AND THE ONE MODEL THAT COULD SHOW THIS...
THE NAM...WAS NOT USED. SO HEAVIER AMOUNTS OF SNOW IN FRONTAL
INSTABILITY BANDS COULD OCCUR...AND IF THEY DO...RIGHT NOW THE MOST
LIKELY PLACE WOULD PROBABLY BE ALONG AND EAST OF A BROOKINGS SD TO
SPENCER IA LINE. THEREFORE PUT THESE AREAS IN A WINTER STORM WATCH.
AND EVEN WITHOUT THE FRONTAL BANDING...THESE AREAS ADD UP TO AROUND
8 INCHES OF STORM TOTAL SNOW IN A 24 TO 36 HOUR PERIOD. IT REALLY
NEEDS TO BE STRESSED HOWEVER THAT ANY STORM TRACK DEVIATION COULD
HAVE HUGE CONSEQUENCES ON SNOW AMOUNTS. THERE WILL LIKELY BE AN
EXTREMELY SHARP CUTOFF OF PRECIPITATION ON THE SOUTHERN END OF THE
SNOW SHIELD. AND IF THE NAM TURNS OUT TO BE MORE CORRECT IN
PLACEMENT AND KEEPING THINGS FURTHER NORTH...OUR FORECAST AREA WILL
BE MUCH MORE DRY SLOTTED. CONVERSELY...IF THE TRACK HEDGES SOUTH...
THEN WE WILL NEED TO PUT HEAVIER SNOW TOTALS AND HEADLINES TO THE
WEST OF OUR CURRENT WATCH. SO ADJUSTMENTS IN FUTURE FORECASTS WILL
BE LIKELY. /MJF
IN THE EXTENDED PERIOD...TUESDAY THROUGH FRIDAY...THE SYSTEM BEGINS
TO PULL AWAY FROM THE AREA WITH LINGERING LIGHT SNOW...MAINLY IN OUR
EAST...DIMINISHING THROUGH THE DAY. THERMAL PROFILES CONTINUE TO
COOL ON TUESDAY...AND WITH CLOUD COVER AND LIKELY SNOW COVER STAYED
ON THE COOLER SIDE OF GUIDANCE WITH HIGHS IN THE UPPER 20S ALONG THE
MISSOURI RIVER CORRIDOR TO THE LOWER 20S NORTHEAST. A SURFACE RIDGE
AXIS BUILDS SOUTHWARD INTO OUR AREA DURING THE DAY...BECOMING
SITUATED DIRECTLY OVERHEAD ON TUESDAY NIGHT. WITH CLEARING
SKIES...DYING WINDS...AND FRESH SNOW COVER...WENT BELOW ALL BLEND
GUIDANCE...AND IT MAY ACTUALLY BE EVEN COLDER IF THINGS SET UP
RIGHT. AT THIS POINT HAVE LOWS IN THE LOWER SINGLE DIGITS NORTHEAST
TO THE LOWER AND MID TEENS IN THE FAR WEST.
UPPER LEVEL RIDGING BEGINS TO BUILD INTO THE REGION ON
WEDNESDAY...AS THE SURFACE HIGH PRESSURE PUSHES OFF TO THE EAST WITH
A SOUTHERLY LOW LEVEL FLOW DEVELOPING ON THE BACKSIDE OF THE HIGH.
AS A RESULT...TEMPERATURES WILL ATTEMPT TO WARM ACROSS THE
AREA...THOUGH STUNTED BY SNOW COVER. THE BEST WARMING POTENTIAL
LOOKS TO BE IN OUR SOUTHWEST WITH HIGHS INTO THE UPPER
30S...TAPERING DOWN TO THE EAST WITH READINGS ONLY IN THE MID 20S
NORTH AND EAST OF A GENERAL BROOKINGS TO SPENCER LINE. WINDS WILL
BEGIN TO PICK UP ON WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT AS THE
GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING LOW PRESSURE TROUGH
OVER THE EASTERN ROCKIES/WESTERN HIGH PLAINS. AS A RESULT...IT WILL
BE A MUCH MILDER NIGHT ON WEDNESDAY NIGHT WITH LOWS UPPER 20S WEST
TO MID/UPPER TEENS EAST.
THURSDAY WILL BE THE WARM DAY OF THE WEEK IN A STRONG SOUTHERLY FLOW
OUT AHEAD OF THE AFOREMENTIONED SURFACE TROUGH. AGAIN...DEEPER SNOW
COVER IN SOME AREAS WILL TEMPER HIGHS SOMEWHAT...THOUGH PORTIONS OF
OUR SOUTH CENTRAL SOUTH DAKOTA ZONES MAY MAKE IT UP INTO THE UPPER
40S WHERE PROGGED 925 MB TEMPS WILL REACH JUST EITHER SIDE OF 10C ON
THURSDAY AFTERNOON. BACK TO THE NORTH AND EAST...WHERE THERE IS THE
POTENTIAL FOR DEEPER SNOW COVER...HIGHS WILL MOST LIKELY BE STUCK IN
THE 30S.
ON FRIDAY...THE GFS AND ECMWF IN DECENT AGREEMENT ON BRINGING UPPER
LEVEL ENERGY ACROSS NORTH DAKOTA...PROBABLY KEEPING ANY
PRECIPITATION POTENTIAL TO THE NORTH OF US...THOUGH PULLING A COLD
FRONT THROUGH OUR AREA LATE THURSDAY NIGHT INTO FRIDAY. LOOKS TO BE
A DRY FRONTAL PASSAGE FOR THE MOST PART WITH LIMITED MOISTURE WITH
THE SYSTEM...THOUGH WILL RESULT IN A COOL DOWN FOR FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR SDZ040.
MN...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR MNZ071-072-080-081-089-090-097.
IA...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR IAZ002-003-014.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
505 AM CST SAT MAR 2 2013
.DISCUSSION.../ISSUED AT 400 AM CST/
NEAR TERM CHALLENGE IS THE LAST REMNANTS OF SOME STRATUS NOSING UP
INTO PARTS OF NORTHWEST IA...ALONG AND JUST EAST OF THE BIG SIOUX
RIVER AT THIS TIME. SITUATED NEAR 925MB...IT IS SLOWLY EDGING
SOUTHWARD AND SHOULD CONTINUE TO PROCEED IN THAT DIRECTION THROUGH
15Z THIS MORNING. AT THAT TIME...BOTH THE NAM12 AND RAP ARE IN GOOD
AGREEMENT IN SHIFTING THE 925MB WINDS FROM THE NORTH/NORTHWEST TO
THE SOUTH BETWEEN 15Z AND 18Z. THEREFORE IF ANY STRATUS IS STILL IN
OUR FAR SOUTHEAST ZONES AT 15Z...IT MAY HAVE TROUBLE LEAVING THAT
AREA UNLESS IT MIXES OUT SOME. OTHERWISE...MID AND HIGH LEVEL CLOUDS
WILL INCREASE TODAY GIVING A PARTLY SUNNY TO MOSTLY CLOUDY SKY
OVERALL. SURFACE RIDGING IS MOVING EASTWARD AT THIS TIME ACROSS OUR
FORECAST AREA WHICH WILL SHIFT THE SURFACE WINDS TO THE SOUTH. GIVEN
THE NAM AND GFS 925MB TEMPERATURES...ANOTHER SEASONALLY COOL DAY
WILL BE IN STORE FOR AREAS ALONG AND EAST OF I 29. HOWEVER OUR
CENTRAL SD ZONES SHOULD WARM INTO THE LOWER AND MID 40S.
NO CHANGES REALLY NEEDED FOR THE TONIGHT PERIOD...WITH A SOUTHEAST
BREEZE STAYING BRISK. THEREFORE NOT ANTICIPATING TEMPERATURES
FALLING OFF ALL THAT MUCH. DUE TO THE BREEZE...WE MAY BE A BIT TOO
COOL WITH THE LOWS TONIGHT SO THAT IS SOMETHING TO WATCH FOR.
ON SUNDAY...WELL ADVERTISED UPPER WAVE BEGINS TO MOVE INTO THE IDAHO
AND WESTERN MT REGION. AHEAD OF IT...SURFACE LOW PRESSURE FORMS IN A
NORTH TO SOUTH ELONGATION ALONG THE FRONT RANGE OF THE ROCKIES. THE
NORTHERN PORTION OF THE LOW THEN EXTENDS A DECENT WARM FRONT
SOUTHEASTWARD INTO THE CENTRAL PLAINS. TO THE NORTH OF THE WARM
FRONT...INDICATIONS ARE INCREASING THAT THERE MAY BE ENOUGH
SATURATION AND ISENTROPIC LIFT TO PRODUCE SOME LIGHT
PRECIPITATION...WITH THE TYPE DEPENDING ON SURFACE TO 850MB
TEMPERATURES. THE MOST CONCERN AT THIS TIME IS IN AN AREA FROM
EASTERN KINGSBURY AND WESTERN BROOKINGS COUNTIES...WHERE THERE COULD
BE SOME LIGHT FREEZING RAIN. RIGHT NOW...HAVE VERY MINIMAL
ACCUMULATIONS OF ICE IN THOSE AREAS BECAUSE SURFACE TEMPERATURES
SHOULD WARM INTO THE LOWER 30S DURING THE AFTERNOON. BUT WILL LIKELY
MENTION THIS POSSIBILITY IN THE FORTH COMING HWO. CLOSER TO THE WARM
FRONT...TEMPERATURES WILL BE QUITE MILD IN OUR CENTRAL SD ZONES...
WITH 40S WIDESPREAD IN THOSE AREAS. CONVERSELY IN OUR NORTHEAST
ZONES...LOWER 30S IS LIKELY ALL THE WARMING THEY WILL GET.
FOR THE REST OF THE FORECAST SUNDAY NIGHT THROUGH MONDAY NIGHT...
FOLLOWED A BLEND OF THE 00Z GFS/00Z GEM GLOBAL AND 12Z ECMWF. THE
NAM LOOKS TO BE A NORTHERN OUTLIER AT THIS TIME AS IT SO OFTEN IS
WITH SYSTEMS IN THE NORTHERN JET STREAM MOVING OUT OF THE NORTHERN
ROCKIES. THAT SAID...THE 00Z ECMWF DID ALSO TREND A BIT FURTHER
NORTHWARD WITH THE STORM TRACK COMPARED WITH ITS 12Z COUNTERPART.
HAVE NOTICED THE LAST COUPLE OF DAYS THAT THE ECMWF IS BATTLING
ITSELF WITH THE 00Z RUNS FURTHER NORTH THEN THE 12Z RUNS WHICH IS
INTERESTING.
ON SUNDAY NIGHT...MOST OF THE PRECIPITATION WILL STILL LIKELY LIE
NEAR THE 850MB BAROCLINIC ZONE CLOSE TO THE AFOREMENTIONED WARM
FRONT. BROAD LIFT IS PRETTY STRONG IN OUR NORTHERN AND EASTERN ZONES
ALL NIGHT. AND WITH TEMPERATURES COOLING ALOFT TO SUB ZERO...AGAIN
USING THE ABOVE MENTIONED MODEL BLEND...SNOW WILL BE LIKELY FOR
AREAS NORTH OF OUR MISSOURI RIVER VALLEY COUNTIES. AT THIS TIME...
IT APPEARS UPWARDS OF 3 TO 3.5 INCHES COULD FALL IN AN AXIS FROM
FROM AROUND BROOKINGS...TO WORTHINGTON...TO SPENCER IOWA. LIGHTER
AMOUNTS WILL THEN FOLLOW SUIT ON BOTH SIDES OF THAT AXIS BUT ANY
DEVIATION IN THE STORM TRACK COULD REALLY FOUL UP THIS THINKING. LOW
TEMPERATURES WILL AGAIN NOT LIKELY FALL TOO MUCH FROM DAYTIME
HIGHS...WITH A LOT OF 20S ANTICIPATED. BECAUSE OF TEMPERATURES BELOW
FREEZING COUPLED WITH WARM TEMPERATURES ALOFT...EVEN ON THE SOUTHERN
TRACK SOLUTIONS...AM A BIT CONCERNED ABOUT MORE LIGHT FREEZING RAIN
POTENTIAL LATE SUNDAY NIGHT IN AN AREA FROM CHAMBERLAIN TO LAKE
ANDES.
THEN ON MONDAY AND MONDAY NIGHT...THE AFOREMENTIONED MODEL BLEND
DIVES THE UPPER LOW SOUTHEASTWARD TOWARD TOPEKA KS/KANSAS CITY AREA
BY 12Z TUESDAY. THIS TRACK WOULD BE FAVORABLE FOR GIVING THE
NORTHEAST HALF OF OUR FORECAST AREA ACCUMULATING SNOW EITHER IN THE
ADVISORY OR WARNING CRITERIA CATEGORIES. GFS UPPER QG FORCING IS
MAXIMIZED IN A TRACK JUST SOUTH OF OUR MISSOURI RIVER VALLEY ZONES
WITH STRONG PV FORCING FOLLOWING SUIT. NOW ONE THING TO MENTION...IS
IT IS DIFFICULT TO TELL AT THIS POINT WHERE ANY MESOSCALE TO
MICROSCALE FRONTAL BANDING WILL TAKE PLACE OR ANY POTENTIAL UPPER
INSTABILITY. THE GLOBAL TYPE MODELS HAVE A TENDENCY TO WASH OUT
THESE FEATURES OUT AND THE ONE MODEL THAT COULD SHOW THIS...
THE NAM...WAS NOT USED. SO HEAVIER AMOUNTS OF SNOW IN FRONTAL
INSTABILITY BANDS COULD OCCUR...AND IF THEY DO...RIGHT NOW THE MOST
LIKELY PLACE WOULD PROBABLY BE ALONG AND EAST OF A BROOKINGS SD TO
SPENCER IA LINE. THEREFORE PUT THESE AREAS IN A WINTER STORM WATCH.
AND EVEN WITHOUT THE FRONTAL BANDING...THESE AREAS ADD UP TO AROUND
8 INCHES OF STORM TOTAL SNOW IN A 24 TO 36 HOUR PERIOD. IT REALLY
NEEDS TO BE STRESSED HOWEVER THAT ANY STORM TRACK DEVIATION COULD
HAVE HUGE CONSEQUENCES ON SNOW AMOUNTS. THERE WILL LIKELY BE AN
EXTREMELY SHARP CUTOFF OF PRECIPITATION ON THE SOUTHERN END OF THE
SNOW SHIELD. AND IF THE NAM TURNS OUT TO BE MORE CORRECT IN
PLACEMENT AND KEEPING THINGS FURTHER NORTH...OUR FORECAST AREA WILL
BE MUCH MORE DRY SLOTTED. CONVERSELY...IF THE TRACK HEDGES SOUTH...
THEN WE WILL NEED TO PUT HEAVIER SNOW TOTALS AND HEADLINES TO THE
WEST OF OUR CURRENT WATCH. SO ADJUSTMENTS IN FUTURE FORECASTS WILL
BE LIKELY. /MJF
IN THE EXTENDED PERIOD...TUESDAY THROUGH FRIDAY...THE SYSTEM BEGINS
TO PULL AWAY FROM THE AREA WITH LINGERING LIGHT SNOW...MAINLY IN OUR
EAST...DIMINISHING THROUGH THE DAY. THERMAL PROFILES CONTINUE TO
COOL ON TUESDAY...AND WITH CLOUD COVER AND LIKELY SNOW COVER STAYED
ON THE COOLER SIDE OF GUIDANCE WITH HIGHS IN THE UPPER 20S ALONG THE
MISSOURI RIVER CORRIDOR TO THE LOWER 20S NORTHEAST. A SURFACE RIDGE
AXIS BUILDS SOUTHWARD INTO OUR AREA DURING THE DAY...BECOMING
SITUATED DIRECTLY OVERHEAD ON TUESDAY NIGHT. WITH CLEARING
SKIES...DYING WINDS...AND FRESH SNOW COVER...WENT BELOW ALL BLEND
GUIDANCE...AND IT MAY ACTUALLY BE EVEN COLDER IF THINGS SET UP
RIGHT. AT THIS POINT HAVE LOWS IN THE LOWER SINGLE DIGITS NORTHEAST
TO THE LOWER AND MID TEENS IN THE FAR WEST.
UPPER LEVEL RIDGING BEGINS TO BUILD INTO THE REGION ON
WEDNESDAY...AS THE SURFACE HIGH PRESSURE PUSHES OFF TO THE EAST WITH
A SOUTHERLY LOW LEVEL FLOW DEVELOPING ON THE BACKSIDE OF THE HIGH.
AS A RESULT...TEMPERATURES WILL ATTEMPT TO WARM ACROSS THE
AREA...THOUGH STUNTED BY SNOW COVER. THE BEST WARMING POTENTIAL
LOOKS TO BE IN OUR SOUTHWEST WITH HIGHS INTO THE UPPER
30S...TAPERING DOWN TO THE EAST WITH READINGS ONLY IN THE MID 20S
NORTH AND EAST OF A GENERAL BROOKINGS TO SPENCER LINE. WINDS WILL
BEGIN TO PICK UP ON WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT AS THE
GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING LOW PRESSURE TROUGH
OVER THE EASTERN ROCKIES/WESTERN HIGH PLAINS. AS A RESULT...IT WILL
BE A MUCH MILDER NIGHT ON WEDNESDAY NIGHT WITH LOWS UPPER 20S WEST
TO MID/UPPER TEENS EAST.
THURSDAY WILL BE THE WARM DAY OF THE WEEK IN A STRONG SOUTHERLY FLOW
OUT AHEAD OF THE AFOREMENTIONED SURFACE TROUGH. AGAIN...DEEPER SNOW
COVER IN SOME AREAS WILL TEMPER HIGHS SOMEWHAT...THOUGH PORTIONS OF
OUR SOUTH CENTRAL SOUTH DAKOTA ZONES MAY MAKE IT UP INTO THE UPPER
40S WHERE PROGGED 925 MB TEMPS WILL REACH JUST EITHER SIDE OF 10C ON
THURSDAY AFTERNOON. BACK TO THE NORTH AND EAST...WHERE THERE IS THE
POTENTIAL FOR DEEPER SNOW COVER...HIGHS WILL MOST LIKELY BE STUCK IN
THE 30S.
ON FRIDAY...THE GFS AND ECMWF IN DECENT AGREEMENT ON BRINGING UPPER
LEVEL ENERGY ACROSS NORTH DAKOTA...PROBABLY KEEPING ANY
PRECIPITATION POTENTIAL TO THE NORTH OF US...THOUGH PULLING A COLD
FRONT THROUGH OUR AREA LATE THURSDAY NIGHT INTO FRIDAY. LOOKS TO BE
A DRY FRONTAL PASSAGE FOR THE MOST PART WITH LIMITED MOISTURE WITH
THE SYSTEM...THOUGH WILL RESULT IN A COOL DOWN FOR FRIDAY.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
LINGERING STRATUS JUST TO THE EAST OF KSUX VERY EARLY THIS MORNING
WILL CONTINUE TO PUSH OFF TO THE SOUTHEAST THROUGH THE MORNING WITH
925 MB WINDS OUT OF THE NORTHWEST OVER THAT AREA.
OTHERWISE...POCKETS OF STRATUS OVER THE AREA WILL DISSIPATE THROUGH
THE MORNING WITH SCATTERED MID AND HIGH CLOUDS REMAINING THROUGH THE
DAY. GUIDANCE POINTING TOWARD STRATUS RETURNING TO THE AREA BY LATE
THIS AFTERNOON OR EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR SDZ040.
MN...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR MNZ071-072-080-081-089-090-097.
IA...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR IAZ002-003-014.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
400 AM CST SAT MAR 2 2013
.DISCUSSION.../ISSUED AT 400 AM CST/
NEAR TERM CHALLENGE IS THE LAST REMNANTS OF SOME STRATUS NOSING UP
INTO PARTS OF NORTHWEST IA...ALONG AND JUST EAST OF THE BIG SIOUX
RIVER AT THIS TIME. SITUATED NEAR 925MB...IT IS SLOWLY EDGING
SOUTHWARD AND SHOULD CONTINUE TO PROCEED IN THAT DIRECTION THROUGH
15Z THIS MORNING. AT THAT TIME...BOTH THE NAM12 AND RAP ARE IN GOOD
AGREEMENT IN SHIFTING THE 925MB WINDS FROM THE NORTH/NORTHWEST TO
THE SOUTH BETWEEN 15Z AND 18Z. THEREFORE IF ANY STRATUS IS STILL IN
OUR FAR SOUTHEAST ZONES AT 15Z...IT MAY HAVE TROUBLE LEAVING THAT
AREA UNLESS IT MIXES OUT SOME. OTHERWISE...MID AND HIGH LEVEL CLOUDS
WILL INCREASE TODAY GIVING A PARTLY SUNNY TO MOSTLY CLOUDY SKY
OVERALL. SURFACE RIDGING IS MOVING EASTWARD AT THIS TIME ACROSS OUR
FORECAST AREA WHICH WILL SHIFT THE SURFACE WINDS TO THE SOUTH. GIVEN
THE NAM AND GFS 925MB TEMPERATURES...ANOTHER SEASONALLY COOL DAY
WILL BE IN STORE FOR AREAS ALONG AND EAST OF I 29. HOWEVER OUR
CENTRAL SD ZONES SHOULD WARM INTO THE LOWER AND MID 40S.
NO CHANGES REALLY NEEDED FOR THE TONIGHT PERIOD...WITH A SOUTHEAST
BREEZE STAYING BRISK. THEREFORE NOT ANTICIPATING TEMPERATURES
FALLING OFF ALL THAT MUCH. DUE TO THE BREEZE...WE MAY BE A BIT TOO
COOL WITH THE LOWS TONIGHT SO THAT IS SOMETHING TO WATCH FOR.
ON SUNDAY...WELL ADVERTISED UPPER WAVE BEGINS TO MOVE INTO THE IDAHO
AND WESTERN MT REGION. AHEAD OF IT...SURFACE LOW PRESSURE FORMS IN A
NORTH TO SOUTH ELONGATION ALONG THE FRONT RANGE OF THE ROCKIES. THE
NORTHERN PORTION OF THE LOW THEN EXTENDS A DECENT WARM FRONT
SOUTHEASTWARD INTO THE CENTRAL PLAINS. TO THE NORTH OF THE WARM
FRONT...INDICATIONS ARE INCREASING THAT THERE MAY BE ENOUGH
SATURATION AND ISENTROPIC LIFT TO PRODUCE SOME LIGHT
PRECIPITATION...WITH THE TYPE DEPENDING ON SURFACE TO 850MB
TEMPERATURES. THE MOST CONCERN AT THIS TIME IS IN AN AREA FROM
EASTERN KINGSBURY AND WESTERN BROOKINGS COUNTIES...WHERE THERE COULD
BE SOME LIGHT FREEZING RAIN. RIGHT NOW...HAVE VERY MINIMAL
ACCUMULATIONS OF ICE IN THOSE AREAS BECAUSE SURFACE TEMPERATURES
SHOULD WARM INTO THE LOWER 30S DURING THE AFTERNOON. BUT WILL LIKELY
MENTION THIS POSSIBILITY IN THE FORTH COMING HWO. CLOSER TO THE WARM
FRONT...TEMPERATURES WILL BE QUITE MILD IN OUR CENTRAL SD ZONES...
WITH 40S WIDESPREAD IN THOSE AREAS. CONVERSELY IN OUR NORTHEAST
ZONES...LOWER 30S IS LIKELY ALL THE WARMING THEY WILL GET.
FOR THE REST OF THE FORECAST SUNDAY NIGHT THROUGH MONDAY NIGHT...
FOLLOWED A BLEND OF THE 00Z GFS/00Z GEM GLOBAL AND 12Z ECMWF. THE
NAM LOOKS TO BE A NORTHERN OUTLIER AT THIS TIME AS IT SO OFTEN IS
WITH SYSTEMS IN THE NORTHERN JET STREAM MOVING OUT OF THE NORTHERN
ROCKIES. THAT SAID...THE 00Z ECMWF DID ALSO TREND A BIT FURTHER
NORTHWARD WITH THE STORM TRACK COMPARED WITH ITS 12Z COUNTERPART.
HAVE NOTICED THE LAST COUPLE OF DAYS THAT THE ECMWF IS BATTLING
ITSELF WITH THE 00Z RUNS FURTHER NORTH THEN THE 12Z RUNS WHICH IS
INTERESTING.
ON SUNDAY NIGHT...MOST OF THE PRECIPITATION WILL STILL LIKELY LIE
NEAR THE 850MB BAROCLINIC ZONE CLOSE TO THE AFOREMENTIONED WARM
FRONT. BROAD LIFT IS PRETTY STRONG IN OUR NORTHERN AND EASTERN ZONES
ALL NIGHT. AND WITH TEMPERATURES COOLING ALOFT TO SUB ZERO...AGAIN
USING THE ABOVE MENTIONED MODEL BLEND...SNOW WILL BE LIKELY FOR
AREAS NORTH OF OUR MISSOURI RIVER VALLEY COUNTIES. AT THIS TIME...
IT APPEARS UPWARDS OF 3 TO 3.5 INCHES COULD FALL IN AN AXIS FROM
FROM AROUND BROOKINGS...TO WORTHINGTON...TO SPENCER IOWA. LIGHTER
AMOUNTS WILL THEN FOLLOW SUIT ON BOTH SIDES OF THAT AXIS BUT ANY
DEVIATION IN THE STORM TRACK COULD REALLY FOUL UP THIS THINKING. LOW
TEMPERATURES WILL AGAIN NOT LIKELY FALL TOO MUCH FROM DAYTIME
HIGHS...WITH A LOT OF 20S ANTICIPATED. BECAUSE OF TEMPERATURES BELOW
FREEZING COUPLED WITH WARM TEMPERATURES ALOFT...EVEN ON THE SOUTHERN
TRACK SOLUTIONS...AM A BIT CONCERNED ABOUT MORE LIGHT FREEZING RAIN
POTENTIAL LATE SUNDAY NIGHT IN AN AREA FROM CHAMBERLAIN TO LAKE
ANDES.
THEN ON MONDAY AND MONDAY NIGHT...THE AFOREMENTIONED MODEL BLEND
DIVES THE UPPER LOW SOUTHEASTWARD TOWARD TOPEKA KS/KANSAS CITY AREA
BY 12Z TUESDAY. THIS TRACK WOULD BE FAVORABLE FOR GIVING THE
NORTHEAST HALF OF OUR FORECAST AREA ACCUMULATING SNOW EITHER IN THE
ADVISORY OR WARNING CRITERIA CATEGORIES. GFS UPPER QG FORCING IS
MAXIMIZED IN A TRACK JUST SOUTH OF OUR MISSOURI RIVER VALLEY ZONES
WITH STRONG PV FORCING FOLLOWING SUIT. NOW ONE THING TO MENTION...IS
IT IS DIFFICULT TO TELL AT THIS POINT WHERE ANY MESOSCALE TO
MICROSCALE FRONTAL BANDING WILL TAKE PLACE OR ANY POTENTIAL UPPER
INSTABILITY. THE GLOBAL TYPE MODELS HAVE A TENDENCY TO WASH OUT
THESE FEATURES OUT AND THE ONE MODEL THAT COULD SHOW THIS...
THE NAM...WAS NOT USED. SO HEAVIER AMOUNTS OF SNOW IN FRONTAL
INSTABILITY BANDS COULD OCCUR...AND IF THEY DO...RIGHT NOW THE MOST
LIKELY PLACE WOULD PROBABLY BE ALONG AND EAST OF A BROOKINGS SD TO
SPENCER IA LINE. THEREFORE PUT THESE AREAS IN A WINTER STORM WATCH.
AND EVEN WITHOUT THE FRONTAL BANDING...THESE AREAS ADD UP TO AROUND
8 INCHES OF STORM TOTAL SNOW IN A 24 TO 36 HOUR PERIOD. IT REALLY
NEEDS TO BE STRESSED HOWEVER THAT ANY STORM TRACK DEVIATION COULD
HAVE HUGE CONSEQUENCES ON SNOW AMOUNTS. THERE WILL LIKELY BE AN
EXTREMELY SHARP CUTOFF OF PRECIPITATION ON THE SOUTHERN END OF THE
SNOW SHIELD. AND IF THE NAM TURNS OUT TO BE MORE CORRECT IN
PLACEMENT AND KEEPING THINGS FURTHER NORTH...OUR FORECAST AREA WILL
BE MUCH MORE DRY SLOTTED. CONVERSELY...IF THE TRACK HEDGES SOUTH...
THEN WE WILL NEED TO PUT HEAVIER SNOW TOTALS AND HEADLINES TO THE
WEST OF OUR CURRENT WATCH. SO ADJUSTMENTS IN FUTURE FORECASTS WILL
BE LIKELY. /MJF
IN THE EXTENDED PERIOD...TUESDAY THROUGH FRIDAY...THE SYSTEM BEGINS
TO PULL AWAY FROM THE AREA WITH LINGERING LIGHT SNOW...MAINLY IN OUR
EAST...DIMINISHING THROUGH THE DAY. THERMAL PROFILES CONTINUE TO
COOL ON TUESDAY...AND WITH CLOUD COVER AND LIKELY SNOW COVER STAYED
ON THE COOLER SIDE OF GUIDANCE WITH HIGHS IN THE UPPER 20S ALONG THE
MISSOURI RIVER CORRIDOR TO THE LOWER 20S NORTHEAST. A SURFACE RIDGE
AXIS BUILDS SOUTHWARD INTO OUR AREA DURING THE DAY...BECOMING
SITUATED DIRECTLY OVERHEAD ON TUESDAY NIGHT. WITH CLEARING
SKIES...DYING WINDS...AND FRESH SNOW COVER...WENT BELOW ALL BLEND
GUIDANCE...AND IT MAY ACTUALLY BE EVEN COLDER IF THINGS SET UP
RIGHT. AT THIS POINT HAVE LOWS IN THE LOWER SINGLE DIGITS NORTHEAST
TO THE LOWER AND MID TEENS IN THE FAR WEST.
UPPER LEVEL RIDGING BEGINS TO BUILD INTO THE REGION ON
WEDNESDAY...AS THE SURFACE HIGH PRESSURE PUSHES OFF TO THE EAST WITH
A SOUTHERLY LOW LEVEL FLOW DEVELOPING ON THE BACKSIDE OF THE HIGH.
AS A RESULT...TEMPERATURES WILL ATTEMPT TO WARM ACROSS THE
AREA...THOUGH STUNTED BY SNOW COVER. THE BEST WARMING POTENTIAL
LOOKS TO BE IN OUR SOUTHWEST WITH HIGHS INTO THE UPPER
30S...TAPERING DOWN TO THE EAST WITH READINGS ONLY IN THE MID 20S
NORTH AND EAST OF A GENERAL BROOKINGS TO SPENCER LINE. WINDS WILL
BEGIN TO PICK UP ON WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT AS THE
GRADIENT TIGHTENS IN RESPONSE TO A DEVELOPING LOW PRESSURE TROUGH
OVER THE EASTERN ROCKIES/WESTERN HIGH PLAINS. AS A RESULT...IT WILL
BE A MUCH MILDER NIGHT ON WEDNESDAY NIGHT WITH LOWS UPPER 20S WEST
TO MID/UPPER TEENS EAST.
THURSDAY WILL BE THE WARM DAY OF THE WEEK IN A STRONG SOUTHERLY FLOW
OUT AHEAD OF THE AFOREMENTIONED SURFACE TROUGH. AGAIN...DEEPER SNOW
COVER IN SOME AREAS WILL TEMPER HIGHS SOMEWHAT...THOUGH PORTIONS OF
OUR SOUTH CENTRAL SOUTH DAKOTA ZONES MAY MAKE IT UP INTO THE UPPER
40S WHERE PROGGED 925 MB TEMPS WILL REACH JUST EITHER SIDE OF 10C ON
THURSDAY AFTERNOON. BACK TO THE NORTH AND EAST...WHERE THERE IS THE
POTENTIAL FOR DEEPER SNOW COVER...HIGHS WILL MOST LIKELY BE STUCK IN
THE 30S.
ON FRIDAY...THE GFS AND ECMWF IN DECENT AGREEMENT ON BRINGING UPPER
LEVEL ENERGY ACROSS NORTH DAKOTA...PROBABLY KEEPING ANY
PRECIPITATION POTENTIAL TO THE NORTH OF US...THOUGH PULLING A COLD
FRONT THROUGH OUR AREA LATE THURSDAY NIGHT INTO FRIDAY. LOOKS TO BE
A DRY FRONTAL PASSAGE FOR THE MOST PART WITH LIMITED MOISTURE WITH
THE SYSTEM...THOUGH WILL RESULT IN A COOL DOWN FOR FRIDAY.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MVFR STRATUS WILL SLOWLY ERODE ACROSS NORTHWEST IOWA. SOME SHORT
LIVED FOG DEVELOPED IN THE JAMES VALLEY...BUT WILL SEE INCREASE IN
EASTERLY WINDS AND INCREASE IN CIRRUS SHOULD LIMIT FURTHER
DEVELOPMENT. NEAR LOW LEVEL RIDGE AXIS AS IT SHIFTS CLOSER TO THE
I29 CORRIDOR LIKELY THAT AREAS OF MVFR FOG WILL DEVELOP IN THE
08Z-15Z TIMEFRAME...BUT COVERAGE WILL BE SOMEWHAT DEPENDENT ON
THICKNESS OF APPROACHING CIRRUS SHIELD AND HOW QUICKLY THE
SOUTHEASTERLY GRADIENT INCREASES. INCREASE IN VFR CEILING COVERAGE
WILL OCCUR ON SATURDAY. HOWEVER...LOWER MVFR CEILINGS EXPECTED TO
DEVELOP IN STABLY STRATIFIED AIRMASS ACROSS THE ENTIRE AREA DURING
THE EVENING ON SATURDAY. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR SDZ040.
MN...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR MNZ071-072-080-081-089-090-097.
IA...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT
FOR IAZ002-003-014.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1133 AM CST SAT MAR 2 2013
.SHORT TERM...TODAY THROUGH TUESDAY
332 AM CST SAT MAR 2 2013
UPDATED LAST PARAGRAPH ABOUT THE ACCUMULATING SNOW POTENTIAL FOR
SUNDAY NIGHT THROUGH TUESDAY...MENTIONING THAT WINTER STORM WATCHES
MAY BE REQUIRED.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING AGAIN OVER THE WESTERN U.S. AND BEGINNING TO ENTER
THE WESTERN PORTION OF THE PLAINS...WHILE TROUGHING STILL
DOMINATED THE EASTERN U.S. A SHORTWAVE TROUGH WAS EVIDENT OVER THE
FORECAST AREA...PRODUCING SOME CIRRUS AHEAD OF IT OVER EASTERN
WISCONSIN. OTHERWISE...THE AIRMASS HAS DRIED OUT QUITE A
BIT...NOTED BY THE 00Z MPX SOUNDING WITH A PRECIPITABLE WATER OF
0.17 INCHES OR 71 PERCENT OF NORMAL. A LIGHT NORTHERLY BREEZE
CONTINUES AHEAD OF A HIGH PRESSURE RIDGE IN FAR WESTERN MINNESOTA.
THIS BREEZE HAS SO FAR KEPT TEMPERATURES FROM COMPLETELY
PLUMMETING. FARTHER WEST...MID AND HIGH CLOUDS WERE INCREASING
ACROSS THE DAKOTAS AHEAD OF THE BUILDING UPPER RIDGE...IN A
GENERAL WARM ADVECTION PATTERN. NO EVIDENCE YET OF PRECIPITATION
FALLING OUT OF THEM...LIKELY DUE TO THE DRY AIR BETWEEN 600-800MB
ON THE 00Z BIS SOUNDING. AIRMASS AROUND THE NORTHERN PLAINS HAS
WARMED UP SOMEWHAT WITH 850MB TEMPS FROM ABR TO MPX AND GRB AROUND
-8C PER 00Z SOUNDINGS. THE MPX AND GRB OBSERVATIONS WERE ABOUT 2C
WARMER THAN WHAT 01.00Z MODELS FORECASTED. WELL OFF TO THE
WEST...A POTENT UPPER TROUGH WAS LOCATED OVER THE EAST PACIFIC
NEAR 45 N 139 W...WHICH WE ARE WATCHING FOR EARLY NEXT WEEK.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR SOME LIGHT SNOW LATE TONIGHT/SUNDAY MORNING...
THE AREA OF THICKENING MID/HIGH CLOUDS ACROSS THE DAKOTAS WILL
EVENTUALLY SHIFT OVER THE FORECAST AREA TONIGHT AS THE WESTERN U.S.
RIDGE GETS PUSHED EASTWARD. ACCOMPANYING THE MID/HIGH CLOUDS IS SOME
LOW TO MID LEVEL FRONTOGENESIS AND WEAK ISENTROPIC LIFT ON THE
280-285K SURFACES. THE MAIN QUESTION IS IF ANY SNOW THAT IS PRODUCED
OUT OF THESE CLOUDS AND LIFT CAN MAKE IT TO THE SURFACE. THE 02.00Z
GFS/NAM/ECMWF/CANADIAN ARE ALL DRY...SUGGESTING THAT THE LOW LEVEL
DRY AIR LEFT BEHIND BY THE SURFACE RIDGE CROSSING THE FORECAST AREA
WILL BE ENOUGH TO ABSORB THE SNOW. ONLY THE 01.21Z SREF YIELDS A
SMALL POSSIBILITY OF SNOW ACROSS MUCH OF EASTERN MINNESOTA SUNDAY
MORNING. WILL LEAN TOWARDS THE MAJORITY IDEA AND KEEP A DRY FORECAST
GOING.
2. ACCUMULATING SNOW POTENTIAL SUNDAY NIGHT THROUGH TUESDAY...
GOOD MODEL AGREEMENT EXISTS THAT A FRONTOGENETIC BAND OF
PRECIPITATION WILL FORM FROM THE DAKOTAS SOUTHEAST INTO NORTHWEST
IOWA BY LATE SUNDAY. THIS BAND FORMS BECAUSE OF INTENSIFYING WARM
ADVECTION COMBINING WITH PACIFIC MOISTURE...DOWNSTREAM OF THE POTENT
TROUGH CURRENTLY IN THE EAST PACIFIC MOVING INTO MONTANA.
WHERE THE FRONTOGENETIC BAND GOES FROM HERE IN TIME HAS BEEN
PROBLEMATIC THE LAST COUPLE DAYS...AND THERE REMAINS PROBLEMS TODAY.
PART OF THE ISSUE IS SOLELY JUST ON THE POTENT TROUGH TRACK AND
SPEED. THE SPREAD AT 00Z TUESDAY RANGES FROM THE EASTERN DAKOTAS IN
THE 02.00Z NAM...CENTRAL DAKOTAS IN THE 02.00Z UKMET/ECMWF...AND THE
WESTERN DAKOTAS IN THE 02.00Z CANADIAN/GFS. IT IS WORTH NOTING THAT
THE LOCATION FROM ALL MODELS IS DEFINITELY WEST AND SLOWER THAN
THOSE SEEN FROM THE 01.00Z CYCLE. THE FASTER NAM WOULD BRING THE
FRONTOGENETIC SNOW BAND TO MUCH OF THE AREA ON MONDAY...WITH
POTENTIALLY SOME MODERATE TO HEAVY SNOW IN LA CROSSE. HOWEVER...THE
NAM HAS BEEN CONSIDERED AN OUTLIER SOLUTION. FOR THE WESTERN GROUP
OF THE CANADIAN/GFS...THIS GROUP WOULD ONLY BRING SOME LIGHT SNOW TO
A PORTION OF NORTHEAST IOWA AND THE AUSTIN AREA SUNDAY NIGHT. THE
SNOW THEN EXPANDS EAST A LITTLE ON MONDAY AND EXITS TO THE SOUTHEAST
TUESDAY AFTERNOON. FINALLY THE UKMET/ECMWF ARE KIND OF A COMPROMISE
BETWEEN THE GFS/CANADIAN AND THE NAM.
GIVEN THE DEFINITE SLOW DOWN SIGNAL PRESENT IN ALL MODELS WITH THE
UPPER TROUGH...HAVE TRENDED THE FORECAST THIS WAY. THE RESULT IS TO
THE KEEP THE HIGHEST PRECIPITATION CHANCES IN THE FAR WEST
SOUTHEASTERN MINNESOTA COUNTIES INTO NORTHEAST IOWA FOR LATE SUNDAY
NIGHT THROUGH TUESDAY...WITH LOWER CHANCES TO PRACTICALLY DRY BY THE
TIME YOU HEAD EAST TOWARDS I-94. APPEARS THERE COULD BE TWO
PERIODS OF MORE MODERATE SNOWFALL...ONE WITH THE INITIAL WAVE OF
FRONTOGENESIS/WARM ADVECTION...THEN THE SECOND AND FINAL ONE
ACCOMPANYING THE UPPER TROUGH AS IT DIGS SOUTH INTO MISSOURI ON
TUESDAY.
STILL GIVEN THE MODEL VARIABILITY...IT IS HARD TO SPECULATE ON
SNOWFALL AMOUNTS. ONE CONCERN IS THAT THE MAXIMUM QPF WHEREVER THE
FRONTOGENESIS BAND LAYS UP COULD END UP AT OR ABOVE 1 INCH...
ACCORDING TO THE CANADIAN...GFS...NAM AND SREF. THE ECMWF SUGGEST
HALF OF THAT...BUT THE LOWER TOTAL MAY BE A RESULT OF THE 80 KM
HORIZONTAL RESOLUTION AS WELL AS WEAKER FORCING. THE LIQUID QPF
COMBINED WITH SNOW TO WATER RATIOS LIKELY IN THE 10-15 TO 1 RANGE
FOR THIS EVENT WOULD RESULT IN 36 HOUR TOTALS OF 10 TO 12
INCHES...POSSIBLY MORE. THUS...A WINTER STORM WATCH MAY BE REQUIRED.
RIGHT NOW CONFIDENCE IS JUST NOT HIGH ENOUGH TO ISSUE THE WATCH
BECAUSE OF PLACEMENT PROBLEMS WITH THE SNOW BAND.
3. TEMPERATURES THROUGHOUT THE SHORT TERM...
TEMPERATURES TODAY LOOK TO END UP SIMILAR TO YESTERDAY GIVEN PLENTY
OF SUN BUT THE COOLER START AND 850MB TEMPS HOLDING NEARLY STEADY.
TONIGHT COULD GET QUITE CHILLY...PRIMARILY OVER WISCONSIN WHERE THE
MID/HIGH CLOUDS TAKE LONGER TO ARRIVE. STAYED TOWARDS THE COOL SIDE
OF GUIDANCE OVER WISCONSIN. THE DIURNAL CHANGE SHRINKS FOR SUNDAY
THROUGH MONDAY NIGHT...THOUGH READINGS DO LOOK WARMER... WITH PLENTY
OF CLOUDS AROUND FROM THE SYSTEM AFFECTING THE AREA. WENT WITH A
BLEND OF GUIDANCE FOR HIGHS/LOWS SUNDAY THROUGH MONDAY NIGHT.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
215 AM CST SAT MAR 2 2013
MODEL AGREEMENT AMONGST THE 02.00Z ECMWF/CANADIAN/GFS AND GFS
ENSEMBLES IS PRETTY GOOD THROUGH THE LONG TERM PERIOD. GENERAL IDEA
IS THAT THE UPPER TROUGH AFFECTING THE AREA ON TUESDAY WILL HEAD
SOUTHEAST INTO THE MID-ATLANTIC REGION BY WEDNESDAY...PUSHED ALONG
BY UPPER RIDGING BUILDING EAST/NORTH INTO THE PLAINS. THUS...DRIER
CONDITIONS ARE ANTICIPATED ACROSS THE ENTIRE AREA FOR TUESDAY NIGHT
INTO WEDNESDAY.
DEFINITE PATTERN SHIFT FORECAST THROUGH THE REST OF THE WEEK WITH
TROUGHING OVER THE WESTERN U.S. AND RIDGING SHIFTING EAST AND
BUILDING OVER THE EASTERN U.S.. IN ADDITION...IT APPEARS THE UPPER
TROUGHING IN THE WESTERN U.S. IS EVENTUALLY GOING TO SPLIT INTO
TWO...WITH THE SOUTHERN PART CUTTING OFF IN THE SOUTHWEST U.S. AND
THE NORTHERN PART BRINGING A COLD FRONT THROUGH THE AREA COME
FRIDAY. PERHAPS WE MAY SEE SOME LIGHT PRECIPITATION WITH THIS
FRONTAL PASSAGE THURSDAY NIGHT INTO FRIDAY...BUT THE FRONT IS
MOISTURE AND FORCING STARVED. THUS...ONLY HAVE 20 PERCENT CHANCES AT
THE PRESENT TIME. OTHERWISE...DRY CONDITIONS PREVAIL. TEMPERATURES
ARE GOING TO BE ON THE RISE AS WELL...ESPECIALLY COME FRIDAY AHEAD
OF THE COLD FRONT. BY FRIDAY...HIGHS APPEAR ABOVE NORMAL. EVEN
BEHIND THE FRONT LOOKING AHEAD TO THE WEEKEND...THE AIRMASS DOES NOT
LOOK THAT COLD GIVEN A PACIFIC FLOW OF AIR IN ITS WAKE.
&&
.AVIATION...THROUGH 18Z SUNDAY
1133 AM CST SAT MAR 2 2013
A SHORT WAVE TROUGH OVER THE NORTHERN PLAINS WILL MOVE SOUTHEAST
THROUGH THE ARE TONIGHT. MID CLOUDS /AROUND 12K FEET/ WILL MOVE
INTO THE AREA LATE THIS AFTERNOON AND EARLY EVENING. THESE CLOUDS
WILL EVENTUALLY LOWER INTO THE 5-8K FOOT RANGE OVERNIGHT AND
REMAIN THERE THROUGH SUNDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SAT MAR 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1107 AM CST SAT MAR 2 2013
.UPDATE...
QUIET WEATHER IN THE TODAY PERIOD AS HIGH PRESSURE MOVES IN FROM
WESTERN ONTARIO AND MINNESOTA. MAIN CONCERNS ARE SKY COVER AND
TEMPS. VIS SAT SHOWS MOSTLY SUNNY SKIES WEST OF THE LAKE SHORE
COUNTIES AND THE NORTHEAST QUAD OF THE CWA. CLOUDS THOUGH ARE
BETTER SEEN LOOKING AT THE FOG/11-3.9 MICRON PRODUCT. WHEREIN...A
SWATH OF CLOUDS WITH 1700 FT BASES ARE MORE EVIDENT AND ARE
DOWNSTREAM OF KGRB-TO-KFLD. IN ADDITION...THERE ARE LAKE-ENHANCED
CLOUDS WITH 2500-3000 FT BASES THAT ARE PRESENT ACROSS THE LAKE
SHORE COUNTIES.
SATELLITE TRENDS IN CONJUNCTION WITH RH AND WIND PROGS FAVOR
CLOUDS STICKING AROUND IN THE LAKE SHORE COUNTIES AT LEAST UNTIL
THE LOW LEVEL WINDS BECOME MORE N-TO-NW LATE IN THE
AFTERNOON/EVENING. THE SWATH OF CLOUDS DOWN STREAM OF KGRB ARE
EXPECTED TO DRIFT SOUTH WITH TIME TODAY. WITH EROSION ALREADY
EVIDENT AROUND THE EDGES OF THE SWATH...DO ANTICIPATE IT TO THIN
AND SHRINK AS IT DRIFTS SOUTHWARD. NAM AND RAP BUFKIT SOUNDINGS AT
KOSH SUPPORT IT STICKING AROUND WITH THE LOW-LEVEL MOISTURE
PLENTIFUL JUST BELOW THE INVERSION/ALMOST NEAR ISOTHERMAL LEVEL
THAT BEGINS AROUND 900-850 HPA.
RADAR MOSAIC SHOWS A SHORE-PARALLEL LES BAND ACROSS LAKE MICHIGAN.
HOWEVER...GIVEN BUFKIT SOUNDINGS AND WIND PROFILES...DO NOT
ANTICIPATE IT DRIFTING BACK TOWARDS THE SE WI SHORE. ALSO THE
LATEST HRRR AND LOCAL WRF MODEL RUNS SUPPORT THIS AS THEY KEEP ANY
PRECIP MID-LAKE/DOWN INTO IN/IL.
TEMP TRENDS WERE ALSO MODIFIED SLIGHTLY. 925 HPA TEMPS SHOW A
GENERAL CONSENSUS OF AROUND -8 TO -10 C. IN THE WEST HALF OF THE
CWA...THIS WOULD CORRESPOND TO AROUND 27/28 F IF MIXED DOWN DRY
ADIABATICALLY WHICH SEEMS REASONABLE...THOUGH MUST STILL ACCOUNT
FOR SNOW COVER. IN THE EAST HALF OF THE CWA...A BIT MORE TRICKY
GIVEN THE SKY COVER SITUATION. AS SUCH...HIGHS WERE KEPT THERE
BETWEEN 24-26 F BUT WILL MONITOR AS SKIES EVOLVE TODAY.
ET
&&
.AVIATION/18Z TAFS/...
FOR THE EASTERN TAF SITES...CEILINGS WILL LINGER BETWEEN VFR AND
MVFR LEVELS THROUGH THIS AFTERNOON...FINALLY PUSHING SOUTHEAST OF
THE AREA BY 00Z SUNDAY. VFR CONDITIONS THEN EXPECTED TONIGHT AND
SUNDAY. NORTH WINDS WILL LINGER THIS AFTERNOON...BEFORE WEAKENING
AND BECOMING NORTHWEST TONIGHT. LIGHT NORTHWEST WINDS WILL VEER
NORTHEAST BY LATE SUNDAY. MAY SEE A FEW HIGH CLOUDS SUNDAY.
FOR MADISON...EXPECT VFR CONDITIONS THROUGH SUNDAY. NORTH WINDS
WILL WEAKEN AND BECOME LIGHT AND VARIABLE TONIGHT. MAY SEE
SCATTERED HIGH CLOUDS MOVE INTO THE AREA LATER TONIGHT INTO
SUNDAY. LIGHT WINDS WILL GRADUALLY BECOME EAST SUNDAY.
WOOD
&&
.MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL 3 AM CST SUNDAY FOR
THE NEARSHORE WATERS OF LAKE MICHIGAN. TIGHT PRESSURE GRADIENT
WILL SLOWLY RELAX THIS AFTERNOON AND TONIGHT...WHICH WILL ALLOW
NORTH WINDS TO GRADUALLY WEAKEN. SUBSEQUENT HIGH WAVES WILL LINGER
THIS AFTERNOON AND INTO TONIGHT...SLOWLY SUBSIDING BY LATER
TONIGHT AS WINDS WEAKEN.
WOOD
&&
.PREV DISCUSSION... /ISSUED 348 AM CST SAT MAR 2 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
TEMPERATURES REALLY DROPPED OUT IN PORTIONS OF WESTERN CWA WITH ONLY
WISPY HIGH CLOUDS AND LIGHT WINDS PROVIDING FAVORABLE RADIATIONAL
CONDITIONS. RADAR LOOPS SHOWING MORE FOCUSED SINGLE LAKE-EFFECT SNOW
BAND DRIFTING AWAY FROM THE SE WI SHORELINE...WITH THE WEST EDGE OF
THE BROADER AREA OF FLURRIES EXTENDING FROM SHEBOYGAN TO EASTERN
WALWORTH COUNTY.
OPERATIONAL AND HI-RES/RAPID UPDATE MODELS DIFFER ON HOW FAR EAST
OVER THE LAKE THIS BAND WILL SET-UP FOR TODAY. COLD AIR ADVECTION
DEEPENS EQUILIBRIUM LEVELS TO AROUND 4100 FT WITH LAKE-INDUCED CAPE
OF 165 J/KG TO GO WITH DELTA T/S AROUND 13C THIS AFTERNOON. BUT BY
THIS TIME 1000-900MB WINDS FAVOR A MORE OFFSHORE CONVERGENCE
ZONE...THOUGH CLOSE TO THE WESTERN SHORE. WILL KEEP IDEA OF MAINLY
FLURRIES WITH LOW POPS HUGGING THE SHORE...WHILE KEEPING A WATCHFUL
EYE ON MOVEMENT OF BAND THROUGH THE EARLY MORNING.
CLOUDS WILL EVENTUALLY DECREASE OVER EASTERN CWA AS FLOW BECOMES NNW
AND PUSHES LOW-LEVEL/LAKE ENHANCED MOISTURE EAST OF FORECAST AREA BY
LATE AFTERNOON/EVENING. ALONG WITH COLD AIR ADVECTION MENTIONED
ABOVE...SINGLE DIGIT LOWS RETURN FOR TONIGHT.
SUNDAY AND SUNDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
A SHORTWAVE MOVING ACROSS CENTRAL WI ALONG WITH WEAK 850MB WARM AIR
ADVECTION WILL LEAD TO INCREASING MID AND HIGH CLOUDS OVER THE
FORECAST AREA SUN NIGHT. UNCERTAIN ABOUT HOW QUICKLY THE CLOUDS WILL
MOVE IN WHICH WILL AFFECT SUN NIGHT MIN TEMPS. TRENDED A LITTLE
WARMER THAN CONSENSUS AND WARMER THAN THE ECMWF.
MONDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM TO LOW
A STRONG SHORTWAVE REACHING THE PACIFIC NORTHWEST 00Z SUN WILL TRACK
ACROSS MONTANA AND SLOW DOWN OVER THE NORTHERN PLAINS SUN NIGHT AND
MONDAY...ALONG WITH AN ASSOCIATED SURFACE LOW. MEANWHILE...A
SOUTHERN STREAM UPPER SHORTWAVE WILL CROSS THE CENTRAL ROCKIES AND A
LEE CYCLONE WILL DEVELOP AND MOVE OVER OK/KS ON MON. THE TWO SURFACE
LOWS ARE FORECAST TO BECOME SORT OF AN INVERTED TROUGH AS THE SYSTEM
MOVES ACROSS THE MIDWEST ON TUESDAY. A BAND OF SNOW IS FORECAST TO
DEVELOP ON THE NORTHEAST SIDE OF THIS SPRAWLING LOW PRESSURE TROUGH
AND THEN SHIFT EAST ACROSS SOUTHERN WI AND MAYBE CENTRAL WI MON
NIGHT THROUGH TUE NIGHT.
DELAYED THE ONSET OF CHANCE POPS INTO SOUTH CENTRAL WI UNTIL MONDAY
MORNING DUE TO DRY EASTERLY FLOW IN THE LOW AND MID LEVELS.
THERE IS VERY LITTLE AGREEMENT BETWEEN THE MODELS REGARDING THE
INTENSITY OF THE NORTHERN STREAM UPPER CLOSED LOW...THE TRACK OF THE
SURFACE LOW(S)...WHERE THE PRECIP BAND WILL SET UP AND THE QPF
AMOUNTS. EVEN THE RUN-TO-RUN CONSISTENCY WITH INDIVIDUAL MODELS IS
POOR. THE 00Z ECMWF LOOKS SIMILAR TO THE NAM NOW AND THE GFS AND
CANADIAN MODELS NOW LOOK SOMEWHAT ALIKE. PLAN ON PLENTY OF CHANGES
IN THE UPCOMING FORECASTS.
THIS MAY BE A LONG DURATION SNOW EVENT ONCE AGAIN...WITH ECMWF
HANGING ON TO PRECIP CHANCES THROUGH EARLY WED MORNING IN SOUTHEAST
WI.
HIGHS EXPECTED IN THE LOWER 30S THROUGH WED. INCREASED SKY COVER TO
ACCOUNT FOR THIS SYSTEM IN THE VICINITY OF SOUTHERN WI. INCREASED
MIN TEMPS DUE TO THE CLOUDY SKIES AS WELL.
LONG TERM...
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
HIGH PRESSURE WILL MOVE ACROSS THE UPPER MIDWEST ON WED INTO THU.
WARM ADVECTION IN SOUTHERN WI AHEAD OF THE NEXT UPPER TROUGH WILL
LEAD TO TEMPS RISING INTO THE UPPER 30S AND LOWER 40S BY THE END OF
NEXT WEEK. THERE COULD BE SOME LIGHT PRECIP IN THE FORM OF EITHER
RAIN OR SNOW OR DRIZZLE THU NIGHT/FRI WITH THE WARM AIR ADVECTION
PATTERN AND A SHORTWAVE.
AVIATION/12Z TAFS/...
MVFR CLOUD DECK TO HANG ON IN EASTERN TAF SITES UNTIL MID-LATE
AFTERNOON. OCCASIONAL FLURRIES OR A BRIEF LIGHT SNOW SHOWER WILL
AFFECT MKE AND ENW...ENDING AROUND MID-MORNING AS FLOW PUSHES LIGHT
SNOW/FLURRIES OFFSHORE. MAY BE A FEW WIND GUSTS MIXING DOWN THIS
MORNING...BUT THEN WINDS SLOWLY EASE THROUGH THE DAY. NAM SHOWING
SHALLOW LOW-LEVEL MOISTURE BRINGING MVFR DECK BACK IN TONIGHT...BUT
WILL FOLLOW MORE OPTIMISTIC MODEL SOLUTION AND KEEP VFR CONDITIONS
THROUGH THE FORECAST.
MARINE...
NO CHANGE TO SMALL CRAFT ADVISORY. WHILE WINDS HAVE EASED BELOW
CRITERIA...THEY WILL REMAIN STRONG ENOUGH THAT WITH PERSISTENT
NORTHERLY FETCH WILL REQUIRE SOME TIME FOR WAVES TO SUBSIDE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 AM CST SUNDAY FOR LMZ643>646.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...REM
SUNDAY THROUGH FRIDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
518 AM CST SAT MAR 2 2013
.SHORT TERM...TODAY THROUGH TUESDAY
332 AM CST SAT MAR 2 2013
UPDATED LAST PARAGRAPH ABOUT THE ACCUMULATING SNOW POTENTIAL FOR
SUNDAY NIGHT THROUGH TUESDAY...MENTIONING THAT WINTER STORM WATCHES
MAY BE REQUIRED.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING AGAIN OVER THE WESTERN U.S. AND BEGINNING TO ENTER
THE WESTERN PORTION OF THE PLAINS...WHILE TROUGHING STILL
DOMINATED THE EASTERN U.S. A SHORTWAVE TROUGH WAS EVIDENT OVER THE
FORECAST AREA...PRODUCING SOME CIRRUS AHEAD OF IT OVER EASTERN
WISCONSIN. OTHERWISE...THE AIRMASS HAS DRIED OUT QUITE A
BIT...NOTED BY THE 00Z MPX SOUNDING WITH A PRECIPITABLE WATER OF
0.17 INCHES OR 71 PERCENT OF NORMAL. A LIGHT NORTHERLY BREEZE
CONTINUES AHEAD OF A HIGH PRESSURE RIDGE IN FAR WESTERN MINNESOTA.
THIS BREEZE HAS SO FAR KEPT TEMPERATURES FROM COMPLETELY
PLUMMETING. FARTHER WEST...MID AND HIGH CLOUDS WERE INCREASING
ACROSS THE DAKOTAS AHEAD OF THE BUILDING UPPER RIDGE...IN A
GENERAL WARM ADVECTION PATTERN. NO EVIDENCE YET OF PRECIPITATION
FALLING OUT OF THEM...LIKELY DUE TO THE DRY AIR BETWEEN 600-800MB
ON THE 00Z BIS SOUNDING. AIRMASS AROUND THE NORTHERN PLAINS HAS
WARMED UP SOMEWHAT WITH 850MB TEMPS FROM ABR TO MPX AND GRB AROUND
-8C PER 00Z SOUNDINGS. THE MPX AND GRB OBSERVATIONS WERE ABOUT 2C
WARMER THAN WHAT 01.00Z MODELS FORECASTED. WELL OFF TO THE
WEST...A POTENT UPPER TROUGH WAS LOCATED OVER THE EAST PACIFIC
NEAR 45 N 139 W...WHICH WE ARE WATCHING FOR EARLY NEXT WEEK.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR SOME LIGHT SNOW LATE TONIGHT/SUNDAY MORNING...
THE AREA OF THICKENING MID/HIGH CLOUDS ACROSS THE DAKOTAS WILL
EVENTUALLY SHIFT OVER THE FORECAST AREA TONIGHT AS THE WESTERN U.S.
RIDGE GETS PUSHED EASTWARD. ACCOMPANYING THE MID/HIGH CLOUDS IS SOME
LOW TO MID LEVEL FRONTOGENESIS AND WEAK ISENTROPIC LIFT ON THE
280-285K SURFACES. THE MAIN QUESTION IS IF ANY SNOW THAT IS PRODUCED
OUT OF THESE CLOUDS AND LIFT CAN MAKE IT TO THE SURFACE. THE 02.00Z
GFS/NAM/ECMWF/CANADIAN ARE ALL DRY...SUGGESTING THAT THE LOW LEVEL
DRY AIR LEFT BEHIND BY THE SURFACE RIDGE CROSSING THE FORECAST AREA
WILL BE ENOUGH TO ABSORB THE SNOW. ONLY THE 01.21Z SREF YIELDS A
SMALL POSSIBILITY OF SNOW ACROSS MUCH OF EASTERN MINNESOTA SUNDAY
MORNING. WILL LEAN TOWARDS THE MAJORITY IDEA AND KEEP A DRY FORECAST
GOING.
2. ACCUMULATING SNOW POTENTIAL SUNDAY NIGHT THROUGH TUESDAY...
GOOD MODEL AGREEMENT EXISTS THAT A FRONTOGENETIC BAND OF
PRECIPITATION WILL FORM FROM THE DAKOTAS SOUTHEAST INTO NORTHWEST
IOWA BY LATE SUNDAY. THIS BAND FORMS BECAUSE OF INTENSIFYING WARM
ADVECTION COMBINING WITH PACIFIC MOISTURE...DOWNSTREAM OF THE POTENT
TROUGH CURRENTLY IN THE EAST PACIFIC MOVING INTO MONTANA.
WHERE THE FRONTOGENETIC BAND GOES FROM HERE IN TIME HAS BEEN
PROBLEMATIC THE LAST COUPLE DAYS...AND THERE REMAINS PROBLEMS TODAY.
PART OF THE ISSUE IS SOLELY JUST ON THE POTENT TROUGH TRACK AND
SPEED. THE SPREAD AT 00Z TUESDAY RANGES FROM THE EASTERN DAKOTAS IN
THE 02.00Z NAM...CENTRAL DAKOTAS IN THE 02.00Z UKMET/ECMWF...AND THE
WESTERN DAKOTAS IN THE 02.00Z CANADIAN/GFS. IT IS WORTH NOTING THAT
THE LOCATION FROM ALL MODELS IS DEFINITELY WEST AND SLOWER THAN
THOSE SEEN FROM THE 01.00Z CYCLE. THE FASTER NAM WOULD BRING THE
FRONTOGENETIC SNOW BAND TO MUCH OF THE AREA ON MONDAY...WITH
POTENTIALLY SOME MODERATE TO HEAVY SNOW IN LA CROSSE. HOWEVER...THE
NAM HAS BEEN CONSIDERED AN OUTLIER SOLUTION. FOR THE WESTERN GROUP
OF THE CANADIAN/GFS...THIS GROUP WOULD ONLY BRING SOME LIGHT SNOW TO
A PORTION OF NORTHEAST IOWA AND THE AUSTIN AREA SUNDAY NIGHT. THE
SNOW THEN EXPANDS EAST A LITTLE ON MONDAY AND EXITS TO THE SOUTHEAST
TUESDAY AFTERNOON. FINALLY THE UKMET/ECMWF ARE KIND OF A COMPROMISE
BETWEEN THE GFS/CANADIAN AND THE NAM.
GIVEN THE DEFINITE SLOW DOWN SIGNAL PRESENT IN ALL MODELS WITH THE
UPPER TROUGH...HAVE TRENDED THE FORECAST THIS WAY. THE RESULT IS TO
THE KEEP THE HIGHEST PRECIPITATION CHANCES IN THE FAR WEST
SOUTHEASTERN MINNESOTA COUNTIES INTO NORTHEAST IOWA FOR LATE SUNDAY
NIGHT THROUGH TUESDAY...WITH LOWER CHANCES TO PRACTICALLY DRY BY THE
TIME YOU HEAD EAST TOWARDS I-94. APPEARS THERE COULD BE TWO
PERIODS OF MORE MODERATE SNOWFALL...ONE WITH THE INITIAL WAVE OF
FRONTOGENESIS/WARM ADVECTION...THEN THE SECOND AND FINAL ONE
ACCOMPANYING THE UPPER TROUGH AS IT DIGS SOUTH INTO MISSOURI ON
TUESDAY.
STILL GIVEN THE MODEL VARIABILITY...IT IS HARD TO SPECULATE ON
SNOWFALL AMOUNTS. ONE CONCERN IS THAT THE MAXIMUM QPF WHEREVER THE
FRONTOGENESIS BAND LAYS UP COULD END UP AT OR ABOVE 1 INCH...
ACCORDING TO THE CANADIAN...GFS...NAM AND SREF. THE ECMWF SUGGEST
HALF OF THAT...BUT THE LOWER TOTAL MAY BE A RESULT OF THE 80 KM
HORIZONTAL RESOLUTION AS WELL AS WEAKER FORCING. THE LIQUID QPF
COMBINED WITH SNOW TO WATER RATIOS LIKELY IN THE 10-15 TO 1 RANGE
FOR THIS EVENT WOULD RESULT IN 36 HOUR TOTALS OF 10 TO 12
INCHES...POSSIBLY MORE. THUS...A WINTER STORM WATCH MAY BE REQUIRED.
RIGHT NOW CONFIDENCE IS JUST NOT HIGH ENOUGH TO ISSUE THE WATCH
BECAUSE OF PLACEMENT PROBLEMS WITH THE SNOW BAND.
3. TEMPERATURES THROUGHOUT THE SHORT TERM...
TEMPERATURES TODAY LOOK TO END UP SIMILAR TO YESTERDAY GIVEN PLENTY
OF SUN BUT THE COOLER START AND 850MB TEMPS HOLDING NEARLY STEADY.
TONIGHT COULD GET QUITE CHILLY...PRIMARILY OVER WISCONSIN WHERE THE
MID/HIGH CLOUDS TAKE LONGER TO ARRIVE. STAYED TOWARDS THE COOL SIDE
OF GUIDANCE OVER WISCONSIN. THE DIURNAL CHANGE SHRINKS FOR SUNDAY
THROUGH MONDAY NIGHT...THOUGH READINGS DO LOOK WARMER... WITH PLENTY
OF CLOUDS AROUND FROM THE SYSTEM AFFECTING THE AREA. WENT WITH A
BLEND OF GUIDANCE FOR HIGHS/LOWS SUNDAY THROUGH MONDAY NIGHT.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
215 AM CST SAT MAR 2 2013
MODEL AGREEMENT AMONGST THE 02.00Z ECMWF/CANADIAN/GFS AND GFS
ENSEMBLES IS PRETTY GOOD THROUGH THE LONG TERM PERIOD. GENERAL IDEA
IS THAT THE UPPER TROUGH AFFECTING THE AREA ON TUESDAY WILL HEAD
SOUTHEAST INTO THE MID-ATLANTIC REGION BY WEDNESDAY...PUSHED ALONG
BY UPPER RIDGING BUILDING EAST/NORTH INTO THE PLAINS. THUS...DRIER
CONDITIONS ARE ANTICIPATED ACROSS THE ENTIRE AREA FOR TUESDAY NIGHT
INTO WEDNESDAY.
DEFINITE PATTERN SHIFT FORECAST THROUGH THE REST OF THE WEEK WITH
TROUGHING OVER THE WESTERN U.S. AND RIDGING SHIFTING EAST AND
BUILDING OVER THE EASTERN U.S.. IN ADDITION...IT APPEARS THE UPPER
TROUGHING IN THE WESTERN U.S. IS EVENTUALLY GOING TO SPLIT INTO
TWO...WITH THE SOUTHERN PART CUTTING OFF IN THE SOUTHWEST U.S. AND
THE NORTHERN PART BRINGING A COLD FRONT THROUGH THE AREA COME
FRIDAY. PERHAPS WE MAY SEE SOME LIGHT PRECIPITATION WITH THIS
FRONTAL PASSAGE THURSDAY NIGHT INTO FRIDAY...BUT THE FRONT IS
MOISTURE AND FORCING STARVED. THUS...ONLY HAVE 20 PERCENT CHANCES AT
THE PRESENT TIME. OTHERWISE...DRY CONDITIONS PREVAIL. TEMPERATURES
ARE GOING TO BE ON THE RISE AS WELL...ESPECIALLY COME FRIDAY AHEAD
OF THE COLD FRONT. BY FRIDAY...HIGHS APPEAR ABOVE NORMAL. EVEN
BEHIND THE FRONT LOOKING AHEAD TO THE WEEKEND...THE AIRMASS DOES NOT
LOOK THAT COLD GIVEN A PACIFIC FLOW OF AIR IN ITS WAKE.
&&
.AVIATION...TODAY AND TONIGHT
518 AM CST SAT MAR 2 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. HIGH
PRESSURE WILL SLIDE OVER THE TAF SITES TODAY PROVIDING MOSTLY
SUNNY SKIES AND LIGHT NORTHERLY WINDS. LINGERING LOW LEVEL
MOISTURE ACROSS THE AREA COULD LEAD TO A FEW CUMULUS TODAY WITH
CLOUD BASES AROUND 2 KFT. A STORM SYSTEM MOVING INTO THE HIGH
PLAINS TONIGHT INTO SUNDAY WILL SPREAD HIGH/MID LEVEL CLOUDS INTO
TO THE AREA TONIGHT WITH CLOUD BASES IN THE 10 KFT TO 15 KFT
RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SAT MAR 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
332 AM CST SAT MAR 2 2013
.SHORT TERM...TODAY THROUGH TUESDAY
332 AM CST SAT MAR 2 2013
UPDATED LAST PARAGRAPH ABOUT THE ACCUMULATING SNOW POTENTIAL FOR
SUNDAY NIGHT THROUGH TUESDAY...MENTIONING THAT WINTER STORM WATCHES
MAY BE REQUIRED.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING AGAIN OVER THE WESTERN U.S. AND BEGINNING TO ENTER
THE WESTERN PORTION OF THE PLAINS...WHILE TROUGHING STILL
DOMINATED THE EASTERN U.S. A SHORTWAVE TROUGH WAS EVIDENT OVER THE
FORECAST AREA...PRODUCING SOME CIRRUS AHEAD OF IT OVER EASTERN
WISCONSIN. OTHERWISE...THE AIRMASS HAS DRIED OUT QUITE A
BIT...NOTED BY THE 00Z MPX SOUNDING WITH A PRECIPITABLE WATER OF
0.17 INCHES OR 71 PERCENT OF NORMAL. A LIGHT NORTHERLY BREEZE
CONTINUES AHEAD OF A HIGH PRESSURE RIDGE IN FAR WESTERN MINNESOTA.
THIS BREEZE HAS SO FAR KEPT TEMPERATURES FROM COMPLETELY
PLUMMETING. FARTHER WEST...MID AND HIGH CLOUDS WERE INCREASING
ACROSS THE DAKOTAS AHEAD OF THE BUILDING UPPER RIDGE...IN A
GENERAL WARM ADVECTION PATTERN. NO EVIDENCE YET OF PRECIPITATION
FALLING OUT OF THEM...LIKELY DUE TO THE DRY AIR BETWEEN 600-800MB
ON THE 00Z BIS SOUNDING. AIRMASS AROUND THE NORTHERN PLAINS HAS
WARMED UP SOMEWHAT WITH 850MB TEMPS FROM ABR TO MPX AND GRB AROUND
-8C PER 00Z SOUNDINGS. THE MPX AND GRB OBSERVATIONS WERE ABOUT 2C
WARMER THAN WHAT 01.00Z MODELS FORECASTED. WELL OFF TO THE
WEST...A POTENT UPPER TROUGH WAS LOCATED OVER THE EAST PACIFIC
NEAR 45 N 139 W...WHICH WE ARE WATCHING FOR EARLY NEXT WEEK.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR SOME LIGHT SNOW LATE TONIGHT/SUNDAY MORNING...
THE AREA OF THICKENING MID/HIGH CLOUDS ACROSS THE DAKOTAS WILL
EVENTUALLY SHIFT OVER THE FORECAST AREA TONIGHT AS THE WESTERN U.S.
RIDGE GETS PUSHED EASTWARD. ACCOMPANYING THE MID/HIGH CLOUDS IS SOME
LOW TO MID LEVEL FRONTOGENESIS AND WEAK ISENTROPIC LIFT ON THE
280-285K SURFACES. THE MAIN QUESTION IS IF ANY SNOW THAT IS PRODUCED
OUT OF THESE CLOUDS AND LIFT CAN MAKE IT TO THE SURFACE. THE 02.00Z
GFS/NAM/ECMWF/CANADIAN ARE ALL DRY...SUGGESTING THAT THE LOW LEVEL
DRY AIR LEFT BEHIND BY THE SURFACE RIDGE CROSSING THE FORECAST AREA
WILL BE ENOUGH TO ABSORB THE SNOW. ONLY THE 01.21Z SREF YIELDS A
SMALL POSSIBILITY OF SNOW ACROSS MUCH OF EASTERN MINNESOTA SUNDAY
MORNING. WILL LEAN TOWARDS THE MAJORITY IDEA AND KEEP A DRY FORECAST
GOING.
2. ACCUMULATING SNOW POTENTIAL SUNDAY NIGHT THROUGH TUESDAY...
GOOD MODEL AGREEMENT EXISTS THAT A FRONTOGENETIC BAND OF
PRECIPITATION WILL FORM FROM THE DAKOTAS SOUTHEAST INTO NORTHWEST
IOWA BY LATE SUNDAY. THIS BAND FORMS BECAUSE OF INTENSIFYING WARM
ADVECTION COMBINING WITH PACIFIC MOISTURE...DOWNSTREAM OF THE POTENT
TROUGH CURRENTLY IN THE EAST PACIFIC MOVING INTO MONTANA.
WHERE THE FRONTOGENETIC BAND GOES FROM HERE IN TIME HAS BEEN
PROBLEMATIC THE LAST COUPLE DAYS...AND THERE REMAINS PROBLEMS TODAY.
PART OF THE ISSUE IS SOLELY JUST ON THE POTENT TROUGH TRACK AND
SPEED. THE SPREAD AT 00Z TUESDAY RANGES FROM THE EASTERN DAKOTAS IN
THE 02.00Z NAM...CENTRAL DAKOTAS IN THE 02.00Z UKMET/ECMWF...AND THE
WESTERN DAKOTAS IN THE 02.00Z CANADIAN/GFS. IT IS WORTH NOTING THAT
THE LOCATION FROM ALL MODELS IS DEFINITELY WEST AND SLOWER THAN
THOSE SEEN FROM THE 01.00Z CYCLE. THE FASTER NAM WOULD BRING THE
FRONTOGENETIC SNOW BAND TO MUCH OF THE AREA ON MONDAY...WITH
POTENTIALLY SOME MODERATE TO HEAVY SNOW IN LA CROSSE. HOWEVER...THE
NAM HAS BEEN CONSIDERED AN OUTLIER SOLUTION. FOR THE WESTERN GROUP
OF THE CANADIAN/GFS...THIS GROUP WOULD ONLY BRING SOME LIGHT SNOW TO
A PORTION OF NORTHEAST IOWA AND THE AUSTIN AREA SUNDAY NIGHT. THE
SNOW THEN EXPANDS EAST A LITTLE ON MONDAY AND EXITS TO THE SOUTHEAST
TUESDAY AFTERNOON. FINALLY THE UKMET/ECMWF ARE KIND OF A COMPROMISE
BETWEEN THE GFS/CANADIAN AND THE NAM.
GIVEN THE DEFINITE SLOW DOWN SIGNAL PRESENT IN ALL MODELS WITH THE
UPPER TROUGH...HAVE TRENDED THE FORECAST THIS WAY. THE RESULT IS TO
THE KEEP THE HIGHEST PRECIPITATION CHANCES IN THE FAR WEST
SOUTHEASTERN MINNESOTA COUNTIES INTO NORTHEAST IOWA FOR LATE SUNDAY
NIGHT THROUGH TUESDAY...WITH LOWER CHANCES TO PRACTICALLY DRY BY THE
TIME YOU HEAD EAST TOWARDS I-94. APPEARS THERE COULD BE TWO
PERIODS OF MORE MODERATE SNOWFALL...ONE WITH THE INITIAL WAVE OF
FRONTOGENESIS/WARM ADVECTION...THEN THE SECOND AND FINAL ONE
ACCOMPANYING THE UPPER TROUGH AS IT DIGS SOUTH INTO MISSOURI ON
TUESDAY.
STILL GIVEN THE MODEL VARIABILITY...IT IS HARD TO SPECULATE ON
SNOWFALL AMOUNTS. ONE CONCERN IS THAT THE MAXIMUM QPF WHEREVER THE
FRONTOGENESIS BAND LAYS UP COULD END UP AT OR ABOVE 1 INCH...
ACCORDING TO THE CANADIAN...GFS...NAM AND SREF. THE ECMWF SUGGEST
HALF OF THAT...BUT THE LOWER TOTAL MAY BE A RESULT OF THE 80 KM
HORIZONTAL RESOLUTION AS WELL AS WEAKER FORCING. THE LIQUID QPF
COMBINED WITH SNOW TO WATER RATIOS LIKELY IN THE 10-15 TO 1 RANGE
FOR THIS EVENT WOULD RESULT IN 36 HOUR TOTALS OF 10 TO 12
INCHES...POSSIBLY MORE. THUS...A WINTER STORM WATCH MAY BE REQUIRED.
RIGHT NOW CONFIDENCE IS JUST NOT HIGH ENOUGH TO ISSUE THE WATCH
BECAUSE OF PLACEMENT PROBLEMS WITH THE SNOW BAND.
3. TEMPERATURES THROUGHOUT THE SHORT TERM...
TEMPERATURES TODAY LOOK TO END UP SIMILAR TO YESTERDAY GIVEN PLENTY
OF SUN BUT THE COOLER START AND 850MB TEMPS HOLDING NEARLY STEADY.
TONIGHT COULD GET QUITE CHILLY...PRIMARILY OVER WISCONSIN WHERE THE
MID/HIGH CLOUDS TAKE LONGER TO ARRIVE. STAYED TOWARDS THE COOL SIDE
OF GUIDANCE OVER WISCONSIN. THE DIURNAL CHANGE SHRINKS FOR SUNDAY
THROUGH MONDAY NIGHT...THOUGH READINGS DO LOOK WARMER... WITH PLENTY
OF CLOUDS AROUND FROM THE SYSTEM AFFECTING THE AREA. WENT WITH A
BLEND OF GUIDANCE FOR HIGHS/LOWS SUNDAY THROUGH MONDAY NIGHT.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
215 AM CST SAT MAR 2 2013
MODEL AGREEMENT AMONGST THE 02.00Z ECMWF/CANADIAN/GFS AND GFS
ENSEMBLES IS PRETTY GOOD THROUGH THE LONG TERM PERIOD. GENERAL IDEA
IS THAT THE UPPER TROUGH AFFECTING THE AREA ON TUESDAY WILL HEAD
SOUTHEAST INTO THE MID-ATLANTIC REGION BY WEDNESDAY...PUSHED ALONG
BY UPPER RIDGING BUILDING EAST/NORTH INTO THE PLAINS. THUS...DRIER
CONDITIONS ARE ANTICIPATED ACROSS THE ENTIRE AREA FOR TUESDAY NIGHT
INTO WEDNESDAY.
DEFINITE PATTERN SHIFT FORECAST THROUGH THE REST OF THE WEEK WITH
TROUGHING OVER THE WESTERN U.S. AND RIDGING SHIFTING EAST AND
BUILDING OVER THE EASTERN U.S.. IN ADDITION...IT APPEARS THE UPPER
TROUGHING IN THE WESTERN U.S. IS EVENTUALLY GOING TO SPLIT INTO
TWO...WITH THE SOUTHERN PART CUTTING OFF IN THE SOUTHWEST U.S. AND
THE NORTHERN PART BRINGING A COLD FRONT THROUGH THE AREA COME
FRIDAY. PERHAPS WE MAY SEE SOME LIGHT PRECIPITATION WITH THIS
FRONTAL PASSAGE THURSDAY NIGHT INTO FRIDAY...BUT THE FRONT IS
MOISTURE AND FORCING STARVED. THUS...ONLY HAVE 20 PERCENT CHANCES AT
THE PRESENT TIME. OTHERWISE...DRY CONDITIONS PREVAIL. TEMPERATURES
ARE GOING TO BE ON THE RISE AS WELL...ESPECIALLY COME FRIDAY AHEAD
OF THE COLD FRONT. BY FRIDAY...HIGHS APPEAR ABOVE NORMAL. EVEN
BEHIND THE FRONT LOOKING AHEAD TO THE WEEKEND...THE AIRMASS DOES NOT
LOOK THAT COLD GIVEN A PACIFIC FLOW OF AIR IN ITS WAKE.
&&
.AVIATION...
1010 PM CST FRI MAR 1 2013
LATEST FOG/STRATUS SATELLITE IMAGERY SHOWING THE MVFR CLOUDS WELL
SOUTH OF THE TAF SITES...AND CONTINUING A SOUTHWARD PROPAGATION
ACROSS CENTRAL/SOUTHERN IA. LATEST RAP RH FIELDS HAVE ALSO BACKED
OFF ON ITS PREVIOUS ABUNDANCE OF SUB 900 MB MOISTURE...WHICH LED TO
SOME CONCERNS OF STRATUS FORMATION. THIS LOOKS LIKE LESS OF A
POSSIBILITY AND WILL CONTINUE VFR THROUGH THE OVERNIGHT HOURS INTO
SAT MORNING. NAM/GFS/RAP ALL SHOW SOME INCREASE IN LOW LEVEL
HUMIDITY FOR SAT AFTERNOON...FROM EASTERN WI...DECREASING AS YOU
REACH THE MISSISSIPPI RIVER. BELIEVE THIS WILL TRANSLATE INTO SOME
CU. CAN/T RULE OUT SOME BKN CIGS AT KLSE...AND IF SO...WOULD LIKELY
BE AROUND 2.5 KFT. CONFIDENCE LIES WITH A SCT DECK AT THIS MOMENT
THOUGH...AND WILL STICK WITH IT.
LIGHT WIND FIELD SAT NIGHT AS HIGH PRESSURE WORKS OVERHEAD. EXPECT
SOME HIGH CLOUDS HOWEVER AS AN UPPER LEVEL TROUGH AS TRACKS EASTWARD
ACROSS THE REGION. IF NOT FOR THE HIGH CLOUDS...THERE COULD BE A
THREAT FOR SOME BR. LATEST OBSERVATIONS TO THE WEST UNDER THE HIGH
INDICATE SOME VSBY RESTRICTIONS FROM BR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SAT MAR 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
215 AM CST SAT MAR 2 2013
.SHORT TERM...TODAY THROUGH TUESDAY
215 AM CST SAT MAR 2 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING AGAIN OVER THE WESTERN U.S. AND BEGINNING TO ENTER
THE WESTERN PORTION OF THE PLAINS...WHILE TROUGHING STILL
DOMINATED THE EASTERN U.S. A SHORTWAVE TROUGH WAS EVIDENT OVER THE
FORECAST AREA...PRODUCING SOME CIRRUS AHEAD OF IT OVER EASTERN
WISCONSIN. OTHERWISE...THE AIRMASS HAS DRIED OUT QUITE A
BIT...NOTED BY THE 00Z MPX SOUNDING WITH A PRECIPITABLE WATER OF
0.17 INCHES OR 71 PERCENT OF NORMAL. A LIGHT NORTHERLY BREEZE
CONTINUES AHEAD OF A HIGH PRESSURE RIDGE IN FAR WESTERN MINNESOTA.
THIS BREEZE HAS SO FAR KEPT TEMPERATURES FROM COMPLETELY
PLUMMETING. FARTHER WEST...MID AND HIGH CLOUDS WERE INCREASING
ACROSS THE DAKOTAS AHEAD OF THE BUILDING UPPER RIDGE...IN A
GENERAL WARM ADVECTION PATTERN. NO EVIDENCE YET OF PRECIPITATION
FALLING OUT OF THEM...LIKELY DUE TO THE DRY AIR BETWEEN 600-800MB
ON THE 00Z BIS SOUNDING. AIRMASS AROUND THE NORTHERN PLAINS HAS
WARMED UP SOMEWHAT WITH 850MB TEMPS FROM ABR TO MPX AND GRB AROUND
-8C PER 00Z SOUNDINGS. THE MPX AND GRB OBSERVATIONS WERE ABOUT 2C
WARMER THAN WHAT 01.00Z MODELS FORECASTED. WELL OFF TO THE
WEST...A POTENT UPPER TROUGH WAS LOCATED OVER THE EAST PACIFIC
NEAR 45 N 139 W...WHICH WE ARE WATCHING FOR EARLY NEXT WEEK.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR SOME LIGHT SNOW LATE TONIGHT/SUNDAY MORNING...
THE AREA OF THICKENING MID/HIGH CLOUDS ACROSS THE DAKOTAS WILL
EVENTUALLY SHIFT OVER THE FORECAST AREA TONIGHT AS THE WESTERN U.S.
RIDGE GETS PUSHED EASTWARD. ACCOMPANYING THE MID/HIGH CLOUDS IS SOME
LOW TO MID LEVEL FRONTOGENESIS AND WEAK ISENTROPIC LIFT ON THE
280-285K SURFACES. THE MAIN QUESTION IS IF ANY SNOW THAT IS PRODUCED
OUT OF THESE CLOUDS AND LIFT CAN MAKE IT TO THE SURFACE. THE 02.00Z
GFS/NAM/ECMWF/CANADIAN ARE ALL DRY...SUGGESTING THAT THE LOW LEVEL
DRY AIR LEFT BEHIND BY THE SURFACE RIDGE CROSSING THE FORECAST AREA
WILL BE ENOUGH TO ABSORB THE SNOW. ONLY THE 01.21Z SREF YIELDS A
SMALL POSSIBILITY OF SNOW ACROSS MUCH OF EASTERN MINNESOTA SUNDAY
MORNING. WILL LEAN TOWARDS THE MAJORITY IDEA AND KEEP A DRY FORECAST
GOING.
2. ACCUMULATING SNOW POTENTIAL SUNDAY NIGHT THROUGH TUESDAY...
GOOD MODEL AGREEMENT EXISTS THAT A FRONTOGENETIC BAND OF
PRECIPITATION WILL FORM FROM THE DAKOTAS SOUTHEAST INTO NORTHWEST
IOWA BY LATE SUNDAY. THIS BAND FORMS BECAUSE OF INTENSIFYING WARM
ADVECTION COMBINING WITH PACIFIC MOISTURE...DOWNSTREAM OF THE POTENT
TROUGH CURRENTLY IN THE EAST PACIFIC MOVING INTO MONTANA.
WHERE THE FRONTOGENETIC BAND GOES FROM HERE IN TIME HAS BEEN
PROBLEMATIC THE LAST COUPLE DAYS...AND THERE REMAINS PROBLEMS TODAY.
PART OF THE ISSUE IS SOLELY JUST ON THE POTENT TROUGH TRACK AND
SPEED. THE SPREAD AT 00Z TUESDAY RANGES FROM THE EASTERN DAKOTAS IN
THE 02.00Z NAM...CENTRAL DAKOTAS IN THE 02.00Z UKMET/ECMWF...AND THE
WESTERN DAKOTAS IN THE 02.00Z CANADIAN/GFS. IT IS WORTH NOTING THAT
THE LOCATION FROM ALL MODELS IS DEFINITELY WEST AND SLOWER THAN
THOSE SEEN FROM THE 01.00Z CYCLE. THE FASTER NAM WOULD BRING THE
FRONTOGENETIC SNOW BAND TO MUCH OF THE AREA ON MONDAY...WITH
POTENTIALLY SOME MODERATE TO HEAVY SNOW IN LA CROSSE. HOWEVER...THE
NAM HAS BEEN CONSIDERED AN OUTLIER SOLUTION. FOR THE WESTERN GROUP
OF THE CANADIAN/GFS...THIS GROUP WOULD ONLY BRING SOME LIGHT SNOW TO
A PORTION OF NORTHEAST IOWA AND THE AUSTIN AREA SUNDAY NIGHT. THE
SNOW THEN EXPANDS EAST A LITTLE ON MONDAY AND EXITS TO THE SOUTHEAST
TUESDAY AFTERNOON. FINALLY THE UKMET/ECMWF ARE KIND OF A COMPROMISE
BETWEEN THE GFS/CANADIAN AND THE NAM.
GIVEN THE DEFINITE SLOW DOWN SIGNAL PRESENT IN ALL MODELS WITH THE
UPPER TROUGH...HAVE TRENDED THE FORECAST THIS WAY. THE RESULT IS TO
THE KEEP THE HIGHEST PRECIPITATION CHANCES IN THE FAR WEST
SOUTHEASTERN MINNESOTA COUNTIES INTO NORTHEAST IOWA FOR LATE SUNDAY
NIGHT THROUGH TUESDAY...WITH LOWER CHANCES TO PRACTICALLY DRY BY THE
TIME YOU HEAD EAST TOWARDS I-94. APPEARS THERE COULD BE TWO
PERIODS OF MORE MODERATE SNOWFALL...ONE WITH THE INITIAL WAVE OF
FRONTOGENESIS/WARM ADVECTION...THEN THE SECOND AND FINAL ONE
ACCOMPANYING THE UPPER TROUGH AS IT DIGS SOUTH INTO MISSOURI ON
TUESDAY.
STILL GIVEN THE MODEL VARIABILITY...IT IS HARD TO SPECULATE ON
SNOWFALL AMOUNTS. BEST GUESS AT THIS TIME WOULD BE FLOYD COUNTY IOWA
HAVING THE MOST...PERHAPS UP TO 6 INCHES FROM SUNDAY NIGHT THROUGH
TUESDAY. THIS IS A LONG DRAWN OUT SNOW. SHOULD THE 02.00Z NAM
SCENARIO PLAY OUT...WE DEFINITELY WOULD BE LOOKING AT MORE
SNOW...AND FARTHER EAST.
3. TEMPERATURES THROUGHOUT THE SHORT TERM...
TEMPERATURES TODAY LOOK TO END UP SIMILAR TO YESTERDAY GIVEN PLENTY
OF SUN BUT THE COOLER START AND 850MB TEMPS HOLDING NEARLY STEADY.
TONIGHT COULD GET QUITE CHILLY...PRIMARILY OVER WISCONSIN WHERE THE
MID/HIGH CLOUDS TAKE LONGER TO ARRIVE. STAYED TOWARDS THE COOL SIDE
OF GUIDANCE OVER WISCONSIN. THE DIURNAL CHANGE SHRINKS FOR SUNDAY
THROUGH MONDAY NIGHT...THOUGH READINGS DO LOOK WARMER... WITH PLENTY
OF CLOUDS AROUND FROM THE SYSTEM AFFECTING THE AREA. WENT WITH A
BLEND OF GUIDANCE FOR HIGHS/LOWS SUNDAY THROUGH MONDAY NIGHT.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
215 AM CST SAT MAR 2 2013
MODEL AGREEMENT AMONGST THE 02.00Z ECMWF/CANADIAN/GFS AND GFS
ENSEMBLES IS PRETTY GOOD THROUGH THE LONG TERM PERIOD. GENERAL IDEA
IS THAT THE UPPER TROUGH AFFECTING THE AREA ON TUESDAY WILL HEAD
SOUTHEAST INTO THE MID-ATLANTIC REGION BY WEDNESDAY...PUSHED ALONG
BY UPPER RIDGING BUILDING EAST/NORTH INTO THE PLAINS. THUS...DRIER
CONDITIONS ARE ANTICIPATED ACROSS THE ENTIRE AREA FOR TUESDAY NIGHT
INTO WEDNESDAY.
DEFINITE PATTERN SHIFT FORECAST THROUGH THE REST OF THE WEEK WITH
TROUGHING OVER THE WESTERN U.S. AND RIDGING SHIFTING EAST AND
BUILDING OVER THE EASTERN U.S.. IN ADDITION...IT APPEARS THE UPPER
TROUGHING IN THE WESTERN U.S. IS EVENTUALLY GOING TO SPLIT INTO
TWO...WITH THE SOUTHERN PART CUTTING OFF IN THE SOUTHWEST U.S. AND
THE NORTHERN PART BRINGING A COLD FRONT THROUGH THE AREA COME
FRIDAY. PERHAPS WE MAY SEE SOME LIGHT PRECIPITATION WITH THIS
FRONTAL PASSAGE THURSDAY NIGHT INTO FRIDAY...BUT THE FRONT IS
MOISTURE AND FORCING STARVED. THUS...ONLY HAVE 20 PERCENT CHANCES AT
THE PRESENT TIME. OTHERWISE...DRY CONDITIONS PREVAIL. TEMPERATURES
ARE GOING TO BE ON THE RISE AS WELL...ESPECIALLY COME FRIDAY AHEAD
OF THE COLD FRONT. BY FRIDAY...HIGHS APPEAR ABOVE NORMAL. EVEN
BEHIND THE FRONT LOOKING AHEAD TO THE WEEKEND...THE AIRMASS DOES NOT
LOOK THAT COLD GIVEN A PACIFIC FLOW OF AIR IN ITS WAKE.
&&
.AVIATION...
1010 PM CST FRI MAR 1 2013
LATEST FOG/STRATUS SATELLITE IMAGERY SHOWING THE MVFR CLOUDS WELL
SOUTH OF THE TAF SITES...AND CONTINUING A SOUTHWARD PROPAGATION
ACROSS CENTRAL/SOUTHERN IA. LATEST RAP RH FIELDS HAVE ALSO BACKED
OFF ON ITS PREVIOUS ABUNDANCE OF SUB 900 MB MOISTURE...WHICH LED TO
SOME CONCERNS OF STRATUS FORMATION. THIS LOOKS LIKE LESS OF A
POSSIBILITY AND WILL CONTINUE VFR THROUGH THE OVERNIGHT HOURS INTO
SAT MORNING. NAM/GFS/RAP ALL SHOW SOME INCREASE IN LOW LEVEL
HUMIDITY FOR SAT AFTERNOON...FROM EASTERN WI...DECREASING AS YOU
REACH THE MISSISSIPPI RIVER. BELIEVE THIS WILL TRANSLATE INTO SOME
CU. CAN/T RULE OUT SOME BKN CIGS AT KLSE...AND IF SO...WOULD LIKELY
BE AROUND 2.5 KFT. CONFIDENCE LIES WITH A SCT DECK AT THIS MOMENT
THOUGH...AND WILL STICK WITH IT.
LIGHT WIND FIELD SAT NIGHT AS HIGH PRESSURE WORKS OVERHEAD. EXPECT
SOME HIGH CLOUDS HOWEVER AS AN UPPER LEVEL TROUGH AS TRACKS EASTWARD
ACROSS THE REGION. IF NOT FOR THE HIGH CLOUDS...THERE COULD BE A
THREAT FOR SOME BR. LATEST OBSERVATIONS TO THE WEST UNDER THE HIGH
INDICATE SOME VSBY RESTRICTIONS FROM BR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 AM CST SAT MAR 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1010 PM CST FRI MAR 1 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
318 PM CST FRI MAR 1 2013
AT 3 PM...HIGH PRESSURE WAS LOCATED OVER HUDSON BAY. A RIDGE OF
HIGH PRESSURE EXTENDS SOUTHWEST INTO WESTERN MINNESOTA. CLOSER
HOME...THE FORECAST AREA IS STILL UNDER THE INFLUENCE OF A LOW
PRESSURE SYSTEM OFF OF THE NEW ENGLAND COAST. THIS LOW KEPT THE
AREA MOSTLY CLOUDY THIS MORNING...BUT SKIES HAVE BEEN CLEARING
FROM NORTHEAST TO SOUTHWEST AS DRIER AIR MOVES INTO THE REGION.
THIS TREND IS EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE
AFTERNOON AND EVENING.
FOR TONIGHT...THE 01.12Z MODELS SHOW A WEAKENING SHORT WAVE TROUGH
MOVE EAST THROUGH THE FORECAST AREA. THIS SYSTEM PRODUCES SOME
WEAK OMEGA BETWEEN 600 AND 300 MB. THIS LIFT WILL AID IN THE
GENERATION OF A FEW MID AND HIGH CLOUDS AS THE 290-310K ISENTROPIC
DEFICITS DECREASE TO 10 TO 30 MB.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE EAST
THROUGH THE REGION. WEAK TO MODERATE 280K ISENTROPIC LIFT DEVELOPS
AHEAD OF THIS WAVE. THIS HELPS THE CONDENSATION PRESSURE DEFICITS
TO DROP TO 10 MB OR LESS. WHILE THERE IS SATURATION BETWEEN 850
AND 750 MB...THE AIR MASS BELOW REMAINS VERY DRY IN THE BUFKIT
SOUNDINGS...THUS KEPT THE FORECAST DRY.
ON SUNDAY NIGHT...MOST OF THE 01.12Z MODELS SHIFTED BACK TO THE
SOUTH FROM THE 01.00Z AND 01.06Z MODELS. THE LONE EXCEPTION IS THE
NAM WHICH IS MUCH FURTHER NORTHEAST WITH ITS TRACK.
OVERALL...PREFER THE GFS TRACK THE BEST. IT HAS BEEN BY FAR...THE
MOST CONSISTENT MODEL WITH THE TRACK OF THIS SYSTEM...THEREFORE...
THE FORECAST WAS TRENDED TOWARD IT. AS A SYSTEM MOVES SOUTHEAST
INTO THE NORTHERN PLAINS FROM THE CANADIAN PROVIDENCES...800 TO
700 MB FRONTOGENESIS WILL DEVELOP ACROSS SOUTHERN MINNESOTA...AND
NORTHERN AND EASTERN IOWA. THIS WILL RESULT IN A BAND OR BANDS OF
SNOW ACROSS THIS AREA. THE HIGHEST PRECIPITATION PROBABILITIES AND
QPF WAS TRENDED TOWARD THAT AREA. AT THIS TIME...SNOW AMOUNTS LOOK
TO BE UP TO AN INCH.
.LONG TERM...MONDAY THROUGH FRIDAY
318 PM CST FRI MAR 1 2013
ON MONDAY...CONTINUED TO TREND THE FORECAST TOWARD THE MORE
CONSISTENT GFS. IT SHOWS WEAK TO MODERATE 800 TO 600 MB FRONTOGENESIS
CONTINUING TO BE FOUND ACROSS SOUTHERN MINNESOTA AND NORTHERN AND
EASTERN IOWA. SOUNDINGS CONTINUE TO SUGGEST THAT THE PRECIPITATION
WILL BE SNOW WITH AMOUNTS LESS THAN AN INCH.
ON MONDAY NIGHT AND TUESDAY...BOTH THE GEM AND GFS SHOW THAT
ANOTHER WAVE WILL MOVE SOUTHWEST OF THE FORECAST AREA. MEANWHILE
THE ECMWF IS MUCH FURTHER NORTHEAST AND IT PRODUCES SNOW ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. ORIGINALLY WAS LEANING
TOWARD THE GEM AND GFS SOLUTIONS. HOWEVER 5 OF THE 12 GFS FAMILY
MEMBERS DO SUPPORT THE ECMWF...SO STAYED WITH THE ALL BLEND. SNOW
AMOUNTS AT THIS TIME LOOK TO BE LESS THAN AN INCH.
&&
.AVIATION...
1010 PM CST FRI MAR 1 2013
LATEST FOG/STRATUS SATELLITE IMAGERY SHOWING THE MVFR CLOUDS WELL
SOUTH OF THE TAF SITES...AND CONTINUING A SOUTHWARD PROPAGATION
ACROSS CENTRAL/SOUTHERN IA. LATEST RAP RH FIELDS HAVE ALSO BACKED
OFF ON ITS PREVIOUS ABUNDANCE OF SUB 900 MB MOISTURE...WHICH LED TO
SOME CONCERNS OF STRATUS FORMATION. THIS LOOKS LIKE LESS OF A
POSSIBILITY AND WILL CONTINUE VFR THROUGH THE OVERNIGHT HOURS INTO
SAT MORNING. NAM/GFS/RAP ALL SHOW SOME INCREASE IN LOW LEVEL
HUMIDITY FOR SAT AFTERNOON...FROM EASTERN WI...DECREASING AS YOU
REACH THE MISSISSIPPI RIVER. BELIEVE THIS WILL TRANSLATE INTO SOME
CU. CAN/T RULE OUT SOME BKN CIGS AT KLSE...AND IF SO...WOULD LIKELY
BE AROUND 2.5 KFT. CONFIDENCE LIES WITH A SCT DECK AT THIS MOMENT
THOUGH...AND WILL STICK WITH IT.
LIGHT WIND FIELD SAT NIGHT AS HIGH PRESSURE WORKS OVERHEAD. EXPECT
SOME HIGH CLOUDS HOWEVER AS AN UPPER LEVEL TROUGH AS TRACKS EASTWARD
ACROSS THE REGION. IF NOT FOR THE HIGH CLOUDS...THERE COULD BE A
THREAT FOR SOME BR. LATEST OBSERVATIONS TO THE WEST UNDER THE HIGH
INDICATE SOME VSBY RESTRICTIONS FROM BR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
318 PM CST FRI MAR 1 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
400 AM EST MON MAR 4 2013
.DISCUSSION...
TODAY-TONIGHT...
HIGH PRESSURE BUILDING INTO THE AREA FROM THE GULF WITH THE CENTER
OVER EAST CENTRAL FLORIDA BY LATE AFTERNOON WITH CALMING WINDS. THIS
MORNING MARKS THE END OF THE CURRENT COLD SPELL AND ALTHOUGH
AFTERNOON HIGH TEMPERATURES WILL STILL BE ABOUT 10 DEGREES COOLER
THAN NORMAL TODAY...THEY`LL STILL BE SIGNIFICANTLY WARMER THAN THE
PAST COUPLE OF DAYS.
TEMPERATURES TONIGHT WILL REBOUND A BIT FROM THE PAST FEW NIGHTS BUT
STILL DROP INTO THE MID 30S TO 40S. WIND CHILLS WON`T BE A FACTOR
DUE TO THE LACK OF WIND WITH HIGH PRESSURE OVERHEAD.
TUE-WED...
THE H30-H20 JET PATTERN ACRS THE SRN CONUS HAS A STRONG ZONAL
COMPONENT THAT WILL MAINTAIN A PROGRESSIVE WX PATTERN THRU MIDWEEK.
THIS JET WILL ALLOW THE LARGE TROF OVER THE CENTRAL CONUS TO DEVELOP
INTO A POTENT STORM SYSTEM THAT WILL CRANK THE NEXT COLD FRONT THRU
CENTRAL FL TUE NIGHT INTO WED.
WHILE THIS FROPA WILL BRING THE NEXT BEST CHANCE FOR PRECIP TO
CENTRAL FL...AHEAD OF THE SYSTEM...AN H100-H70 ANTICYCLONE CENTERED
OVER THE WRN GOMEX WILL PUSH ACRS THE FL PENINSULA AND INTO THE WRN
ATLC BY DAYBREAK TUE. DEEP LYR W/NW FLOW WILL ACCOMPANY THE PASSAGE
OF THE RIDGE THAT WILL LIMIT THE WINDOW OF OPPORTUNITY FOR THE LCL
AIRMASS TO MOISTEN AHEAD OF THE ANTICIPATED FROPA.
THE AIRMASS OVER FL IS ALREADY QUITE ARID AS IS WITH EVENING
SOUNDINGS MEASURING A SCANT 0.2" PWAT OVER N FL...0.3" CENTRAL FL...
AND 0.5" S FL. WINDS WILL SHIFT TO THE S/SW ON TUE AS THE RIDGE
PUSHES INTO THE ATLC...BUT WITH RAP ANALYSIS INDICATING THE H100-H70
70PCT ISOHUME CLEAR DOWN IN THE SW CARIB...THE FRONT WILL ONLY HAVE
THE MOISTURE POOLING WITHIN ITS TROF TO WORK WITH. NEITHER GFS NOR
ECMWF INDICATES ANY SIG CHANGE IN THE SRN BRANCH OF THE JETSTREAM...
BOTH MAINTAIN THE CURRENT ZONAL ORIENTATION THRU THE END OF THE
WEEK.
POPS WITH THIS SYSTEM LOOK LIKE A CLASSIC "ONE AND DONE"...THOUGH
TIMING OF THE FROPA WILL HAVE THEM STRADDLE TUE NIGHT-WED MORNING
TIME FRAME. WARM W/SW FLOW TUE/TUE NIGHT WILL KEEP TEMPS NEAR AVG.
COLD AIR ADVECTION BEHIND THE FRONT ON WED AS WINDS SHIFT TO THE NW.
MAX TEMPS DIPPING INTO THE M60S/L70S (5-10F BLO AVG)...MIN TEMPS WED
NIGHT IN THE U30S/L40S (10-15F BLO AVG). FROST POTENTIAL WED NIGHT
INTO THU LOOKS LOW AS PGRAD SHOULD REMAIN TIGHT ENOUGH TO PREVENT
DECOUPLING.
THU-SUN...
A LARGE CONTINENTAL RIDGE WILL PUSH ACRS THE ERN HALF OF THE CONUS
THRU THE LATTER HALF OF THE WEEK...GENERATING AN EXTENDED PD OF NRLY
WINDS FOR CENTRAL FL. WINDS WILL GRADUALLY VEER FROM NW ON THU...TO
N ON FRI...THEN NE ON SAT. COOL/DRY AIR ADVECTION WILL RESULT...
KEEPING THE FCST DRY WITH MAX/MIN TEMPS ARND 5-10F BLO AVG THRU
FRI...ARND 5F BLO AVG SAT. BY SUN...ONSHORE FLOW WILL HAVE BEEN IN
PLACE LONG ENOUGH TO ALLOW TEMPS TO RECOVER TO NEAR AVG...BUT
AIRMASS EXPECTED TO REMAIN FAR TOO DRY TO INCLUDE ANY MEANINGFUL
CHANCE OF PRECIP ATTM.
&&
.AVIATION...
VFR WITH WINDS STARTING OUT OF THE NORTHWEST BUT BECOMING LIGHT AND
VARIABLE BY EVENING WITH HIGH PRESSURE OVERHEAD.
&&
.MARINE...
TODAY-TONIGHT...WINDS AND SEAS WILL DIMINISH THIS AFTERNOON WITH
HIGH PRESSURE MOVING INTO THE AREA. ALTHOUGH THE DAY BEGINS WITH A
SMALL CRAFT ADVISORY IN EFFECT FOR THE OFFSHORE ZONES...WINDS WILL
BE NEAR CALM WITH WAVE HEIGHTS OF ONLY 2-4 FEET BY TONIGHT.
TUE-TUE NIGHT...LIGHT TO GENTLE SRLY BREEZE TUE MORNING WILL FRESHEN
OUT OF THE SW AS A HIGH PRES RIDGE PUSHES ACRS FL AND INTO THE W
ATLC. WINDS BCMG W 15-20KTS NEARSHORE...20-25KTS OFFSHORE IN THE
PREDAWN HRS. OFFSHORE COMPONENT WILL LIMIT SEA HEIGHTS TO 2-3FT
NEARSHORE...OFFSHORE SEAS BUILDING FROM 2-3FT IN THE MORNING TO
4-6FT OVERNIGHT.
WED/WED NIGHT...HAZARDOUS BOATING CONDITIONS ANTICIPATED AS
SFC/BNDRY LYR WINDS SHIFT TO A FRESH NW BREEZE BEHIND A FAST MOVING
COLD FRONT. SEAS BUILDING TO 4-5FT NEARSHORE...6-8FT OFFSHORE
THU-FRI...WINDS WILL GRADUALLY DIMINISH AND VEER TO THE N THRU THE
END OF THE WEEK AS A LARGE POST FRONTAL HIGH PRES RIDGE BUILDS ACRS
THE SE CONUS. OVERALL BOATING CONDITIONS EXPECTED TO REMAIN MARGINAL
AT BEST...HOWEVER...AS A MODERATE TO FRESH NRLY BREEZE WILL GENERATE
ROUGH CONDITIONS ACRS THE LCL ATLC...ESPECIALLY IN THE GULF STREAM.
SEAS 3-4FT NEARSHORE AND 4-6FT OFFSHORE.
&&
.FIRE WX...
TODAY-TONIGHT...ANOTHER DRY DAY IS IN STORE BUT AN ONSHORE WIND
COMPONENT AT THE COAST THIS AFTERNOON WILL MEAN THAT CRITICAL RH
VALUES WILL BE LIMITED TO INLAND AREAS. IN ADDITION...WINDS WILL BE
LIGHTER TODAY AT ONLY AROUND 5 MPH COINCIDING WITH THE LOWEST RH
VALUES.
TUE-WED...SFC/TRANSPORT WINDS WILL SHIFT FROM SW ON TUE TO NW ON WED
AS A FAST MOVING COLD FRONT PUSHES THRU CENTRAL FL. AN ALREADY ARID
AIRMASS WILL HAVE LIMITED TIME TO MODIFY AHEAD OF THE FROPA. WHILE
SFC WINDS ON TUE NOT EXPECTED TO EXCEED 15 MPH...ANTICIPATE THE WARM
ADVECTION WILL ALLOW MIN RH VALUES TO FALL BLO 35PCT FOR 6-8HRS OVER
MOST OF EAST CENTRAL FL. BREEZY NW WINDS WED WITH LIMITED PRECIP...
TOTAL QPF BLO 0.10" AREAWIDE. DRY AIR ADVECTION BEHIND THE FRONT
WILL PUSH MIN RH VALUES BLO 35PCT FOR 4-6HRS FOR MOST AREAS W OF
I-95.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 42 73 55 / 0 0 0 30
MCO 66 43 76 58 / 0 0 0 20
MLB 63 42 75 59 / 0 0 0 20
VRB 63 40 76 58 / 0 0 0 20
LEE 65 44 75 56 / 0 0 0 30
SFB 65 43 75 57 / 0 0 0 20
ORL 65 46 75 58 / 0 0 0 20
FPR 64 42 75 59 / 0 0 0 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR COASTAL VOLUSIA-
INLAND VOLUSIA-NORTHERN LAKE-SOUTHERN LAKE.
AM...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20
TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE
TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...BOWEN
LONG TERM/IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
333 AM EST MON MAR 4 2013
.DISCUSSION...
TODAY-TONIGHT...
HIGH PRESSURE BUILDING INTO THE AREA FROM THE GULF WITH THE CENTER
OVER EAST CENTRAL FLORIDA BY LATE AFTERNOON WITH CALMING WINDS. THIS
MORNING MARKS THE END OF THE CURRENT COLD SPELL AND ALTHOUGH
AFTERNOON HIGH TEMPERATURES WILL STILL BE ABOUT 10 DEGREES COOLER
THAN NORMAL TODAY...THEY`LL STILL BE SIGNIFICANTLY WARMER THAN THE
PAST COUPLE OF DAYS.
TEMPERATURES TONIGHT WILL REBOUND A BIT FROM THE PAST FEW NIGHTS BUT
STILL DROP INTO THE MID 30S TO 40S. WIND CHILLS WON`T BE A FACTOR
DUE TO THE LACK OF WIND WITH HIGH PRESSURE OVERHEAD.
TUE-WED...
THE H30-H20 JET PATTERN ACRS THE SRN CONUS HAS A STRONG ZONAL
COMPONENT THAT WILL MAINTAIN A PROGRESSIVE WX PATTERN THRU MIDWEEK.
THIS JET WILL ALLOW THE LARGE TROF OVER THE CENTRAL CONUS TO DEVELOP
INTO A POTENT STORM SYSTEM THAT WILL CRANK THE NEXT COLD FRONT THRU
CENTRAL FL TUE NIGHT INTO WED.
WHILE THIS FROPA WILL BRING THE NEXT BEST CHANCE FOR PRECIP TO
CENTRAL FL...AHEAD OF THE SYSTEM...AN H100-H70 ANTICYCLONE CENTERED
OVER THE WRN GOMEX WILL PUSH ACRS THE FL PENINSULA AND INTO THE WRN
ATLC BY DAYBREAK TUE. DEEP LYR W/NW FLOW WILL ACCOMPANY THE PASSAGE
OF THE RIDGE THAT WILL LIMIT THE WINDOW OF OPPORTUNITY FOR THE LCL
AIRMASS TO MOISTEN AHEAD OF THE ANTICIPATED FROPA.
THE AIRMASS OVER FL IS ALREADY QUITE ARID AS IS WITH EVENING
SOUNDINGS MEASURING A SCANT 0.2" PWAT OVER N FL...0.3" CENTRAL FL...
AND 0.5" S FL. WINDS WILL SHIFT TO THE S/SW ON TUE AS THE RIDGE
PUSHES INTO THE ATLC...BUT WITH RAP ANALYSIS INDICATING THE H100-H70
70PCT ISOHUME CLEAR DOWN IN THE SW CARIB...THE FRONT WILL ONLY HAVE
THE MOISTURE POOLING WITHIN ITS TROF TO WORK WITH. NEITHER GFS NOR
ECMWF INDICATES ANY SIG CHANGE IN THE SRN BRANCH OF THE JETSTREAM...
BOTH MAINTAIN THE CURRENT ZONAL ORIENTATION THRU THE END OF THE
WEEK.
POPS WITH THIS SYSTEM LOOK LIKE A CLASSIC "ONE AND DONE"...THOUGH
TIMING OF THE FROPA WILL HAVE THEM STRADDLE TUE NIGHT-WED MORNING
TIME FRAME. WARM W/SW FLOW TUE/TUE NIGHT WILL KEEP TEMPS NEAR AVG.
COLD AIR ADVECTION BEHIND THE FRONT ON WED AS WINDS SHIFT TO THE NW.
MAX TEMPS DIPPING INTO THE M60S/L70S (5-10F BLO AVG)...MIN TEMPS WED
NIGHT IN THE U30S/L40S (10-15F BLO AVG). FROST POTENTIAL WED NIGHT
INTO THU LOOKS LOW AS PGRAD SHOULD REMAIN TIGHT ENOUGH TO PREVENT
DECOUPLING.
THU-SUN...
UPDATE TO FOLLOW.
&&
.AVIATION...
VFR WITH WINDS STARTING OUT OF THE NORTHWEST BUT BECOMING LIGHT AND
VARIABLE BY EVENING WITH HIGH PRESSURE OVERHEAD.
&&
.MARINE...
TODAY-TONIGHT...WINDS AND SEAS WILL DIMINISH THIS AFTERNOON WITH
HIGH PRESSURE MOVING INTO THE AREA. ALTHOUGH THE DAY BEGINS WITH A
SMALL CRAFT ADVISORY IN EFFECT FOR THE OFFSHORE ZONES...WINDS WILL
BE NEAR CALM WITH WAVE HEIGHTS OF ONLY 2-4 FEET BY TONIGHT.
TUE-TUE NIGHT...LIGHT TO GENTLE SRLY BREEZE TUE MORNING WILL FRESHEN
OUT OF THE SW AS A HIGH PRES RIDGE PUSHES ACRS FL AND INTO THE W
ATLC. WINDS BCMG W 15-20KTS NEARSHORE...20-25KTS OFFSHORE IN THE
PREDAWN HRS. OFFSHORE COMPONENT WILL LIMIT SEA HEIGHTS TO 2-3FT
NEARSHORE...OFFSHORE SEAS BUILDING FROM 2-3FT IN THE MORNING TO
4-6FT OVERNIGHT.
WED/WED NIGHT...HAZARDOUS BOATING CONDITIONS ANTICIPATED AS
SFC/BNDRY LYR WINDS SHIFT TO A FRESH NW BREEZE BEHIND A FAST MOVING
COLD FRONT. SEAS BUILDING TO 4-5FT NEARSHORE...6-8FT OFFSHORE
THU-FRI...WINDS WILL GRADUALLY DIMINISH AND VEER TO THE N THRU THE
END OF THE WEEK AS A LARGE POST FRONTAL HIGH PRES RIDGE BUILDS ACRS
THE SE CONUS. OVERALL BOATING CONDITIONS EXPECTED TO REMAIN MARGINAL
AT BEST...HOWEVER...AS A MODERATE TO FRESH NRLY BREEZE WILL GENERATE
ROUGH CONDITIONS ACRS THE LCL ATLC...ESPECIALLY IN THE GULF STREAM.
SEAS 3-4FT NEARSHORE AND 4-6FT OFFSHORE.
&&
TODAY-TONIGHT...ANOTHER DRY DAY IS IN STORE BUT AN ONSHORE WIND
COMPONENT AT THE COAST THIS AFTERNOON WILL MEAN THAT CRITICAL RH
VALUES WILL BE LIMITED TO INLAND AREAS. IN ADDITION...WINDS WILL BE
LIGHTER TODAY AT ONLY AROUND 5 MPH COINCIDING WITH THE LOWEST RH
VALUES.
TUE-WED...UPDATE TO FOLLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 42 73 55 / 0 0 0 30
MCO 66 43 76 58 / 0 0 0 20
MLB 63 42 75 59 / 0 0 0 20
VRB 63 40 76 58 / 0 0 0 20
LEE 65 44 75 56 / 0 0 0 30
SFB 65 43 75 57 / 0 0 0 20
ORL 65 46 75 58 / 0 0 0 20
FPR 64 42 75 59 / 0 0 0 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR COASTAL VOLUSIA-
INLAND VOLUSIA-NORTHERN LAKE-SOUTHERN LAKE.
AM...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20
TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE
TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...BOWEN
LONG TERM/IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1210 AM EST MON MAR 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM THE WEST TONIGHT AND WILL PREVAIL
THROUGH EARLY THIS WEEK. LOW PRESSURE AND ITS TRAILING COLD FRONT
WILL IMPACT THE AREA TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED
AGAIN BY HIGH PRESSURE THROUGH LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
NO MAJOR CHANGES WERE MADE FOR THE EARLY MORNING UPDATE. WATCHING
CIRRUS MOVING IN FROM THE NORTHWEST. RAP 600MB RH PROGS SUGGEST
MOST OF THIS WILL REMAIN TO THE NORTHWEST THROUGH DAYBREAK.
UNDER CLEAR SKIES...TEMPERATURES BY DAYBREAK WILL FALL INTO THE
MID TO UPPER 20S AT MOST LOCATIONS AWAY FROM THE IMMEDIATE COAST.
A FEW OF THE COLDEST LOCATIONS WELL INLAND COULD BRIEFLY BOTTOM
OUT IN THE LOWER 20S...AND TEMPERATURES CLOSE TO FREEZING WILL
EVEN OCCUR ON THE SEA ISLANDS/BEACHES. THESE LOW TEMPERATURES
WILL AVERAGE AS MUCH AS 15-20F BELOW AVERAGE FOR MARCH 4. AT
KSAV...THE MARCH 4 RECORD LOW OF 26 DEGREES LAST SET IN 2009 COULD
BE TIED OR EVEN ECLIPSED.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
MONDAY...THE ABNORMALLY DEEP TROUGH THAT IMPACTED THE AREA OVER THE
WEEKEND WILL FINALLY LIFT OUT...AND BECOMES REPLACED BY A BUILDING
RIDGE FROM THE WEST AND ITS ASSOCIATED RISING HEIGHTS. THE CYCLONIC
FLOW OF RECENT DAYS THAT EXTENDS FAR TO THE SW FROM DEEP LOW
PRESSURE NEAR THE COAST OF MAINE WILL GIVE WAY TO ANTICYCLONIC
CURVATURE OF THE ISOBARS AS HIGH PRESSURE ARRIVES FROM THE WEST.
ALTHOUGH THERE IS AN INCREASE IN JET STREAM CIRRIFORM CLOUDS IN THE
LATE MORNING AND AFTERNOON...CROSS-SECTIONS AND SOUNDINGS INDICATE
THAT THEY WILL BE MORE TRANSLUCENT RATHER THAN OPAQUE. THUS WITH
DECENT INSOLATION...A 20-30 METER RISE IN LOW LEVEL THICKNESS VALUES
AND A SOLID 8-10C CLIMB IN 850 MB TEMPS AND COLD ADVECTION
WANING...WE LOOK TO REACH THE MID 50S NORTH TO AROUND 60 SOUTH.
MONDAY NIGHT...THE SURFACE RIDGE SLIDES INTO THE ATLANTIC...THE
SYNOPTIC FLOW BACKS AROUND TO THE WEST AND SW...AND THERE IS A
STEADY INCREASE IN HIGHER LEVEL CLOUDS. THESE CLOUDS WILL THICKEN
WITH TIME FROM WEST TO EAST IN ASSOCIATION WITH THE UPPER JET AND IN
ADVANCE OF A LOW PRESSURE SYSTEM THAT ORGANIZES AS IT MOVES NE FROM
THE ARKLATEX TO KENTUCKY. WE/LL EXPERIENCE SOME RADIATIONAL COOLING
IN THE EVENING...BUT TEMPS WILL HOLD STEADY OR EVEN RISE LATE.
BOTTOM LINE THOUGHT...WE WILL BE CONSIDERABLE WARMER THAN WE WILL BE
24 HOURS PRIOR.
TUESDAY...A STRONG CUT OFF LOW WILL SHIFT FROM THE NORTHERN PLAINS
TO ILLINOIS...WITH ITS ASSOCIATED SURFACE LOW TO TREK EASTWARD
THROUGH THE OHIO VALLEY TOWARD THE CENTRAL APPALACHIANS. THE FORECAST
ZONES WILL LIE IN THE WARM SECTOR REGIME...WITH A WARM FRONT FOUND
IN NC AND A TRAILING COLD FRONT ORIENTED FROM NE TO SW TO CROSS THE
SOUTHERN PORTION OF THE MOUNTAINS BY 00Z WEDNESDAY. WITH ONLY MINIMAL
HEIGHT FALLS LATE AND THE BEST CONVERGENCE AND DEEPER MOISTURE TO
REMAIN OFF TO OUR WEST AND NW...THE CHANCES FOR ANY RAIN BEFORE
NIGHTFALL ARE SMALL. THERE IS A MOISTENING OF THE COLUMN...BUT THE
LOW LEVELS REMAIN QUITE DRY WITH DEW POINT DEPRESSIONS AS MUCH AS
20-25 DEGREES IF NOT MORE. THUS WE/LL CARRY ONLY 20 POPS IN THE
AFTERNOON NW OF A LINE FROM ABOUT JAMESTOWN TO SUMMERVILLE AND
YEMASSEE IN SC...AND NW OF A LIN FROM ABOUT SHAWNEE TO CLAXTON AND
REIDSVILLE IN GA. LATER FORECASTS MAY NEED TO ADJUST THESE POPS UP
OR DOWN...DEPENDING UPON TIMING OF THE APPROACHING FRONT. DESPITE AN
INCREASE IN CLOUD COVER...STRONG WARM ADVECTION WILL BOOST TEMPS TO
THEIR HIGHEST LEVELS IN ABOUT A WEEK. AWAY FROM THE MUCH COOLER
SHORELINE COMMUNITIES...UPPER 60S AND LOWER 70S WILL BE COMMON JUST
ABOUT EVERYWHERE. A 30-40 KT LOW LEVEL JET WILL SHIFT THROUGH THE
REGION...AND THAT ALONG WITH A TIGHTENING OF THE GRADIENT WILL ALLOW
FOR BREEZY TO WINDY CONDITIONS TO DEVELOP.
TUESDAY NIGHT...THE CUTOFF ALOFT MOVES THROUGH VIRGINIA AND
NC...WHICH TRIGGERS A TRIPLE POINT SURFACE LOW FORMING JUST TO THE
EAST OF THE FEATURE ALOFT. BETTER HEIGHTS FALLS LOCALLY WILL
ACCOMPANY THE LOW...AND THIS WILL WILL DRIVE THE COLD FRONT FAIRLY
QUICKLY THROUGH THE AREA FROM NW TO SE THROUGH THE NIGHT. POPS WILL
EASILY REACH THE 60-70 PERCENTILE...BUT EVEN THESE MAY BE
CONSERVATIVE AS REFINEMENTS WILL LIKELY BE REQUIRED ONCE THE EXACT
TIMING DETAILS ARE HASHED OUT. THERE IS LITTLE IF ANY SURFACE BASED
INSTABILITY...BUT SOME ELEVATED CAPE /200-300 J/KG/...SHOWALTERS
LESS THAN ZERO AND 0-6 KM BULK SHEAR OF 50 KT OR MORE. THEREFORE WE
CAN/T RULE OUT A LITTLE ELEVATED CONVECTION. THE QUICK PROGRESSION
OF THE FRONT SHOULD LIMIT OUR QPF VALUES...MAINLY IN THE RANGE FROM
0.10 TO 0.30 INCHES. WINDS WILL FLUCTUATE THROUGH THE NIGHT...BUT
ONCE THE FRONT MOVES THROUGH AND PRESSURES STEADILY RISE AND COLD
ADVECTION ENSUES...THEY WILL REMAIN ELEVATED AND PERIODICALLY BREEZY
OR EVEN WINDY. TEMPS WILL PLUNGE IN WAKE OF THE FRONT AND NOT FAR FROM
TYPICAL MINIMAL LEVELS.
WEDNESDAY...THE CUT OFF WILL FINALLY TRAP ITS SURFACE LOW UNDERNEATH
NEAR THE MID-ATLANTIC COAST. WE/LL BE IN THE DRY SLOT BEHIND THE
COLD FRONT THAT PULLS FAR AWAY THROUGH THE ATLANTIC...AND THE
WRAP-AROUND MOISTURE ASSOCIATED WITH THE STACKED LOW. ALTHOUGH THERE
ARE HINTS THAT SOME SHOWERS COULD MAKE A RUN FOR OUR FAR NORTHERN
AND/OR NE SECTIONS LATE...WE CURRENTLY ANTICIPATE THAT THE DAY WILL
BE FREE OF ANY PRECIPITATION. TEMPS WILL CERTAINLY BE COLDER THAN ON
TUESDAY...BUT DOWNSLOPE FLOW AND A DECENT AMOUNT OF SUNSHINE WILL
NEGATE SOME OF THE COLDER AIR IMPACTING THE REGION. EVEN SO...WE/RE
LOOKING AT HIGHS AS MUCH AS 10-15 DEGREES COLDER THAN ON TUESDAY. A
TIGHT PRESSURE GRADIENT ND THE PRESENCE OF A 25-35 KT LOW LEVEL JET
WILL PRODUCE A WINDY DAY AREA WIDE. WE MIGHT EVEN FLIRT WITH A WIND
ADVISORY IN SOME LOCALES...WITH WINDS OF 20-30 MPH SUSTAINED AND 35
OR 40 MPH IN GUSTS.
LAKE WINDS...WINDS WILL APPROACH ADVISORY CRITERIA TUESDAY AFTERNOON
AS A 30-40 KT LOW LEVEL JET PASSES OVER THE REGION. HOWEVER...MIXING
WILL BE LIMITED WITHIN A WARM ADVECTION REGIME OVER THE COOLER LAKE
WATERS. A BETTER CHANCE FOR LAKE WIND ADVISORY THRESHOLDS TO BE MET
TUESDAY NIGHT THROUGH EARLY THURSDAY...AS A SIGNIFICANTLY TIGHTENED
PRESSURE GRADIENT AND BOUTS OF STRONG COLD ADVECTION ENHANCES THE
MIXING AND SUPPORTS 20 TO 25 KT AND GUSTY OVER LAKE MOULTRIE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS THE POTENT LOW SYSTEM RAPIDLY TRACKS INTO THE ATLANTIC THROUGH
THE LATE WEEK PERIOD...SURFACE HIGH PRESSURE AND UPPER LEVEL
RIDGING WILL FOLLOW IN ITS WAKE. EXPECT DRY CONDITIONS TO THUS
PREVAIL THURSDAY THROUGH THE WEEKEND. RISING HEIGHTS ALOFT WILL
SUPPORT A GRADUAL WARMING TREND THROUGH THE PERIOD...WITH
TEMPERATURES PEAKING IN THE LOW TO MID 60S THURSDAY AND
FRIDAY...THEN POSSIBLY THE LOW 70S SATURDAY AND SUNDAY. LOW
TEMPERATURES WILL ALSO MODERATE INTO THE UPPER 30S TO LOWER 40S BY
LATE PERIOD.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...THERE IS A LOW TO MODERATE CHANCE OF
REDUCED FLIGHT CONDITIONS AT TIMES TUESDAY NIGHT AS A COLD FRONT
MOVES THROUGH THE AREA...ACCOMPANIED BY NUMEROUS SHRA. WINDY
CONDITIONS WILL ALSO IMPACT THE TERMINALS TUESDAY AFTERNOON
THROUGH THURSDAY.
&&
.MARINE...
MAINTAINED THE ONGOING SCA FOR AMZ354 AND 374 VALID UNTIL 10 AM
MONDAY.
SUNDAY EVENING...THE PRESSURE GRADIENT HAD RELAXED ACROSS SC
WATERS IN RESPONSE TO AN INLAND SURFACE TROUGH N/W OF THE WATERS.
AS A RESULT...WINDS HAD BACKED TOWARD THE SW AND HAD WEAKENED TO
15 KT OR LESS. HOWEVER...00Z GUIDANCE CONTINUES TO ADVERTISE
LOW LEVEL WINDS VEERING TOWARD THE NW AND SURGING TO AS MUCH AS 20
KT ACROSS SC WATERS OVERNIGHT. ACROSS GA NEARSHORE AND OUTER WATERS...
A TIGHTER SURFACE PRESSURE GRADIENT WILL MAINTAIN WINDS IN THE
20-25 KT RANGE...PERHAPS GUSTING NEAR 30 KT 40-60 NM
OFFSHORE...WITH THE WIND DIRECTION VEERING FROM W TO NW OVERNIGHT.
DUE TO THE OFFSHORE FETCH...SEAS SHOULD REMAIN 2-3 FT WITHIN 20 NM
AND 4 TO 6 FT BEYOND 20 NM OVERNIGHT.
MONDAY...AS COLD ADVECTION SHUTS OFF AND THE PRESSURE PATTERN
FINALLY RELAXES AS HIGH PRESSURE BUILDS FROM THE WEST...WINDS AND
SEAS WILL DECREASE THROUGH THE DAY. ONGOING SCA/S WILL END BY 15Z
AND IMPROVING CONDITIONS WILL DEVELOP FOR THE BALANCE OF THE DAY.
MONDAY NIGHT...HIGH PRESSURE WILL SITUATE ITSELF ATOP THE
WATERS...RESULTING IN QUIET MARINE CONDITIONS.
TUESDAY...HIGH PRESSURE ACROSS THE MARINE AREA EARLY WILL GIVE WAY
TO AN AREA OF LOW PRESSURE AND ITS COLD FRONT THAT MOVES THROUGH THE
SE QUADRANT OF THE NATION. THE PRESSURE GRADIENT WILL ONCE AGAIN
BECOME ENHANCED AS THIS PATTERN TRANSPIRES. ALTHOUGH THE WARM
ADVECTION WILL LIMIT MIXING...OUR WINDS AND SEAS WILL NONETHELESS BE
ON A STEADY RISE. AND WE COULD BE LOOKING AT MARGINAL SMALL CRAFT
ADVISORY CONDITIONS YET AGAIN.
TUESDAY NIGHT THROUGH WEDNESDAY...STRONG LOW PRESSURE WILL MOVE EAST
THROUGH THE MID ATLANTIC STATES...WITH ITS ASSOCIATED COLD FRONT TO
SWEEP THROUGH THE COASTAL WATERS THE LATTER PART OF TUESDAY NIGHT.
LARGE ISALLOBARIC PRESSURE FALLS WILL BE FOLLOWED BY LARGE
ISALLOBARIC PRESSURE RISES. THAT ALONG WITH STRONG COLD ADVECTION
DEVELOPING IN WAKE OF THE COLD FRONT WILL LEAD TO A HIGH PROBABILITY
OF GALES OVER MOST IF NOT ALL WATERS. THESE CONDITIONS WILL THEN
PERSIST THROUGH WEDNESDAY...POSSIBLY EVEN INTO WEDNESDAY NIGHT WITH
ANOTHER SURGE OF COLD ADVECTION AND STEADY PRESSURE RISES AS THE
SURFACE LOW MOVES INTO THE WESTERN ATLANTIC. MARINERS ARE ADVISED
THAT A FEW T-STORMS COULD PRECEDE THE COLD FRONT TUESDAY
NIGHT...PERHAPS ACCOMPANIED BY WINDS IN EXCESS OF 35 KT.
THURSDAY AND FRIDAY...THE ATLANTIC LOW WILL EVENTUALLY MOVE AWAY AND
GIVE WAY TO HIGH PRESSURE. IT/LL TAKE AWHILE...BUT IMPROVING
CONDITIONS WILL ARRIVE DURING THIS TIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ354-
374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS LINCOLN IL
315 AM CST MON MAR 4 2013
.DISCUSSION...
ISSUED 315 AM CST MON MAR 4 2013
TIGHT THERMAL GRADIENT MOVING INTO FAR WESTERN ILLINOIS EARLY THIS
MORNING...WITH 850 MB TEMPERATURES RISING ABOUT 6 DEGREES CELSIUS
IN ABOUT A 60 MILE SPAN. ISENTROPIC LIFT ASSOCIATED WITH THIS
GRADIENT HAS PRODUCED SOME LIGHT FREEZING RAIN AND SNOW OVER
IOWA...WITH LIGHT SNOW AND SLEET ACROSS WESTERN ILLINOIS JUST EAST
OF THE MISSISSIPPI RIVER. UPPER LOW DROPPING SOUTHEAST ACROSS
MONTANA IS PART OF THE MAIN SHOW THAT WILL BE AFFECTING OUR
WEATHER THE NEXT COUPLE DAYS...ALONG WITH A SURFACE LOW CURRENTLY
ANALYZED OVER WESTERN OKLAHOMA.
PRIMARY FORECAST CONCERN IN THE SHORT TERM INVOLVES PRECIPITATION
TYPES AND AMOUNTS THROUGH TUESDAY NIGHT. IN THE LONGER TERM...
FOCUS SHIFTS TOWARD A WARMER STORM SYSTEM THAT ARRIVES SOMETIME
NEXT WEEKEND.
SHORT TERM...TODAY THROUGH WEDNESDAY...
STRONGEST LIFT WITH THE CURRENT PRECIPITATION SHOULD LAST THROUGH
ABOUT MID MORNING...AND MOST OF THE MODELS HAVE BEEN WEAKENING
THIS PRECIPITATION WITH TIME. HIGHEST POPS EXPECTED TO BE EARLY
MORNING IN THE NORTHWEST CWA...WITH THE NAM...ECMWF AND RAP MODELS
ALL SUGGESTING MAINLY DRY CONDITIONS THE REMAINDER OF THE DAY.
SURFACE LOW PROGGED TO MOVE INTO WESTERN KENTUCKY AFTER
MIDNIGHT...WITH THE UPPER LOW DROPPING SOUTHEAST INTO CENTRAL
ILLINOIS BY LATE TUESDAY AFTERNOON. PRECIP DEVELOPMENT SHOULD
BEGIN IN EARNEST BY MID TO LATE THIS EVENING AND EXPAND
OVERNIGHT...AS INVERTED SURFACE TROUGH ASSOCIATED WITH THE LOW TO
OUR SOUTH SWINGS THROUGH THE AREA. HAVE SOME CONCERNS WITH PRECIP
TYPES OVERNIGHT AND EARLY TUESDAY...AS NAM AND GFS SOUNDINGS
SHOWING SOME DECENT WARMING IN THE LOWER LAYERS AFTER MIDNIGHT AND
SOME OF THE PRECIP MAY BE RAIN FOR A TIME AS FAR NORTH AS PEORIA.
WITH THE TREND TOWARD SOME WARMER CONDITIONS FOR A TIME... HAVE
HELD OFF ON ANY WINTER HEADLINES AS THE AMOUNT OF SNOW REMAINS IN
FLUX...BUT STILL LOOKS LIKE THE AREAS NORTH OF I-74 ARE MOST LIKELY
TO GET A FEW INCHES OR MORE OF ACCUMULATION THROUGH TUESDAY NIGHT.
MORE OF A TREND TOWARD SNOW IS EXPECTED ON TUESDAY AS THE SURFACE
LOW MOVES UP THE OHIO VALLEY. THE SOUTHEAST CWA IS EXPECTED TO
REMAIN RAIN A GOOD PORTION OF THE TIME...WITH A CHANGEOVER TO SNOW
LATE TUESDAY AFTERNOON. SNOW IS EXPECTED TO LINGER MOST OF THE
EVENING OVER THE ENTIRE AREA AS THE UPPER LOW PASSES...THEN
DIMINISH AFTER MIDNIGHT WITH THE LOW EXITING THE AREA.
LONG TERM...THURSDAY THROUGH SUNDAY...
A MUCH WARMER PATTERN IS STILL ON TAP FOR LATE WEEK...AS AN UPPER
LOW DIGS ALONG THE CALIFORNIA COAST AND PROVIDES A SOUTHWEST FLOW
INTO THE MIDWEST. MAIN FOCUS WILL BE WITH THE EVOLUTION OF THIS
LOW DURING THE WEEKEND...AND HOW THE BRANCHES OF THE JET STREAM
PHASE OVER THE CENTER OF THE COUNTRY. THE GFS MODEL CUTS THE LOW
OFF OVER THE DESERT SOUTHWEST AND PROVIDES MUCH MORE PHASING...
AND THUS A WETTER PATTERN LATER IN THE WEEKEND. MEANWHILE... THE
ECMWF IS MUCH SLOWER WITH LIFTING THE LOW NORTHEAST AND FORMING A
LARGE OCCLUDED SYSTEM OVER THE MID SECTION OF THE NATION...WHICH
WOULD HOLD OFF MUCH OF THE RAIN THREAT UNTIL LATER ON SUNDAY. WILL
GO WITH LOW POPS OF 20-30 PERCENT DURING THE WEEKEND FOR NOW...
HIGHEST IN THE WEST...BUT CONFIDENCE IS LOW DUE TO THE LARGE MODEL
DISCREPANCIES.
GEELHART
&&
.AVIATION...
ISSUED 1151 PM CST SUN MAR 3 2013...FOR THE 06Z TAFS
MID LEVEL WARM AIR ADVECTION IS LIFTING THE BOUNDARY LAYER AIR MASS
AND PRODUCING LIGHT FREEZING RAIN IN MOST OF CENTRAL AND WESTERN IOWA
AND NORTH CENTRAL MISSOURI...WITH LIGHT SNOW REPORTED IN NORTH CENTRAL
IOWA. THAT BAND OF FORCING FOR PRECIP IS ENTERING WC IL AND WILL
EVENTUALLY NEAR SPI AFTER MIDNIGHT. WE EXPECT MAINLY VFR CLOUDS
TONIGHT. SOME IFR CLOUDS AND/OR VIS WILL BE POSSIBLE MONDAY
MORNING MAINLY FOR PIA AS SNOW DEVELOPS AND ACCUMULATES UP TO ONE
HALF INCH OR SO. OTHER TERMINALS WILL HAVE LOWER CHANCES FOR
MEASURABLE SNOW WITH BMI HAVING BETTER CHANCES THAN THE OTHERS.
CAN NOT RULE OUT A BRIEF PERIOD OF FREEZING RAIN OR SLEET FOR
SPI/PIA LATER TONIGHT AND MON MORNING...BUT ICING SHOULD BE
MINIMAL IF ANY DEVELOPS.
GENERALLY A BREAK IN THE PRECIP IS FORECAST FOR MONDAY AFTERNOON
THROUGH MIDNIGHT MON NIGHT...WITH ONLY MINOR LIGHT SNOW OR LIGHT
RAIN EXPECTED. WE LEFT MAINLY A VCSH TO COVER THE OTHER PERIODS
OUTSIDE OF MON MORNING.
WINDS WILL INCREASE FROM THE SOUTHEAST MON MORNING...WITH
SUSTAINED WINDS OF 14-17KT AND GUSTS TO 25KT. DECREASING WINDS
WILL DEVELOP TOWARD SUNSET.
ADDITIONAL SNOWS ARE EXPECTED TO ARRIVE JUST BEYOND THIS 24HR TAF
PERIOD. BY TUESDAY MORNING...SNOW INTENSITY SHOULD INCREASE
DRAMATICALLY FROM WEST TO EAST.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 AM EST MON MAR 4 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 350 PM EST SUN MAR 3 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHORTWAVE TROUGH
OVER NRN MONTANA...A MID/UPPER LEVEL RIDGE OVER THE PLAINS AND NE
CANADA AND TROUGHING OVER NRN MANTIOBA AND THE SE CONUS LEAVING A
COL OVER THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM NW
ONTARIO THROUGH WRN UPPER MI INTO WI AND IL. SIMILAR TO
YESTERDAY...LES AND CLOUDS HAVE DIMINISHED DURING THE AFTERNOON AS
DAYTIME MIXING AND VERY DRY AIS UPSTREAM HELPS ERODE THE
CLOUD BANDS.
TONIGHT AND MON...ALSO SIMILAR TO PREVIOUS FEW NIGHTS...EXPECT SOME LES
TO REDEVLOP OVERNIGHT AS UPSTREAM MIXING/DRYING SUBSIDES AND LAND
BREEZES DEVELOP. HOWEVER...HIGH RES MODELS SUGGEST THAT LOW LEVEL
CONV WILL BE WEAKER THAN LAST NIGHT WITH MAINLY DIFLUENT ACYC FLOW
OVER THE THE WEST HALF OF LAKE SUPERIOR. WEAK UPSLOPE FLOW INTO N
CNTRL UPPER MI SHOULD HELP PRODUCE AT LEAST SOME FLURRIES EVEN WITH
INVERSION HEIGHTS AT OR BELOW 2K-3K FT. WITH LOW CONFIDENCE IN EVEN
ANY LIGHT MEASURABLE LES...FCST RETAINED PREV MENTION OF SLIGHT
CHANCE POPS. FAVORABLE RADIATIONAL COOLING CONDITIONS INLAND SHOULD
WILL ALLOW TEMPS TO DROP TO LOWER END OF GUIDANCE WITH READINGS IN
THE 0 TO 10 BELOW ZERO RANGE.
AS ACYC WINDS BACK TO THE ENE...EXPECT REMAINING LES/FLURRIES TO END
BY MIDDAY MON. TEMPS SHOULD REBOUND TO READINGS CLOSER TO SEASONAL
AVERAGES NEAR 30...PER FCST SOUNDINGS LOW LEVEL TEMP PROFILE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EST SUN MAR 3 2013
FOCUS INITIALY IS ON SHORTWAVE TROUGH DIGGING SOUTHEAST ACROSS
NORTHERN PLAINS. CONVERGENCE AND MOISTURE ADVECTION ALONG AND
NORTH OF SFC/H85/H7 LOWS AND DIVERGENCE ALOFT FROM H25 JET STREAK
SHOULD BE SUPPORTING SWATH OF MODERATE TO HEAVY SNOW FROM EASTERN
NORTH DAKOTA THROUGH MOST OF MINNESOTA AND INTO SOUTHERN WISCONSIN.
H85-H7 FRONTOGENESIS AND H85 MOISTURE STAY FAR ENOUGH TO SOUTH TO
KEEP NORTHERN EDGE OF SNOW SHIELD OUT OF CWA MONDAY NIGHT. H7-H6
FRONTOGENESIS AND INCREASING 1000-700MB MOISTURE PROBABLY WILL ALLOW
SYSTEM SNOW TO CLIP FAR WEST TUESDAY. KIWD WOULD SEE BEST CHANCE OF
SEEING THIS SYSTEM SNOW. FARTHER NORTH...EXPECT INCREASING LIGHT
SNOW MAINLY DUE TO WINDS BECOMING MORE NORTHEAST AND WITH INCREASING
925-850MB MOISTURE. THE ADDITIONAL MOISTURE ALONG WITH FLOW OFF LK
SUPERIOR AND MINOR COOLING AT TOP OF INVERSION TO AROUND -12C WILL
BE SUFFICIENT TO RESULT IN LAKE ENHANCED SNOW. GIVEN THE PERSISTENT
LIGHT LK EFFECT SEEN OFF AND ON OVER NCNTRL UPR MICHIGAN SINCE
THURSDAY WITH QUITE MARGINAL CONDITIONS IN TERMS OF INVERSION
HEIGHT/TEMPS...PRETTY CONFIDENT SNOW WILL OCCUR TUESDAY/TUESDAY
NIGHT/WEDNESDAY MORNING. TOTAL SNOW ACCUMULATIONS WILL BE LIMITED
GIVEN ABSENCE OF LARGER SCALE FORCING AND WITH MAJORITY OF LIFT
OCCURRING AT TEMPS WARMER THAN -10C LEADING TO SLR/S LESS THAN 10:1.
EVEN SO...SOME HIGHER TERRAIN AREAS OVER FAR WESTERN UPR MICHIGAN
AND IN NCNTRL UPR MICHIGAN MAY END UP WITH A FEW INCHES OF SNOW BY
LATER WEDNESDAY.
H925 TEMPS AROUND -10C WITH WEAK NORTHERLY WINDS AND SUFFICIENT
MOISTURE BLO INVERSION WILL RESULT IN LIGHT LK EFFECT PERSISTING
THROUGH LATE WEDNESDAY. SINCE SFC-H925MB WINDS DO NOT BECOME MORE
SOUTHERLY UNTIL THURSDAY MORNING...LIGHT LK EFFECT/FLURRIES PROBABLY
WILL LINGER ALONG PORTIONS OF LK SUPERIOR SHORE WEDNESDAY NIGHT. BY
TIME WINDS DO BECOME MORE SOUTHERLY...TEMPS ARE FURTHER WARMING...SO
DO NOT EXPECT ANY LK EFFECT OFF LK MICHIGAN. COULD BE ENHANCEMENT TO
CLOUDS THOUGH WHICH WOULD TEMPER WARMING ON THURSDAY FOR THE EAST.
H5 RIDGE BUILDS FROM CNTRL CONUS ACROSS GREAT LAKES THURSDAY INTO
FRIDAY. BY LATER FRIDAY...TROUGH OVER WESTERN CONUS SPLITS LEAVING
SEPARATE SOUTHERN STREAM TROUGH OVER SOUTHWEST CONUS AND NORTHERN
STREAM TROUGH PUSHING ACROSS SCNTRL CANADA. SFC-H85 TROUGHING FORMS
IN RESPONSE OVER THE NORTEHRN PLAINS WHICH INCREASES SOUTHERLY
WINDS OVER UPR LAKES THURSDAY NIGHT INTO FRIDAY. WINDS MAY BECOME
BREEZY WITH GUSTS OVER 20 MPH...BUT LACK OF STRONGER PRESSURE
GRADIENT WILL KEEP REAL STRONG WINDS FROM OCCURRING.
GFS INDICATES STRONGER NORTHERN STREAM DYNAMICS HEAD EAST QUICKLY ON
FRIDAY WHILE OUTRUNNING THE SFC TROUGH...SO THE TROUGH REALLY LOSES
ITS PUNCH AS IT MOVES ACROSS THE AREA. ECMWF FAIRLY SIMILAR WITH
OVERALL IDEA. SHOULD NOTE THAT THE GEM-NH A BIT STRONGER/FARTHER
SOUTH WITH NORTHERN STREAM WAVE SO IT GENERATES MORE QPF IN WARM AIR
ADVECTION AHEAD OF THE WAVE ON FRIDAY. GFS TRYING TO GENERATE SOME
LGT DRIZZLE LIKE PRECIP ON FRIDAY WITH LOW-LEVEL MOISTURE BENEATH
DRIER AIR IN MID LEVELS. THINK THAT LACK OF DEEPER MOISTURE INTO THE
SYSTEM SUGGESTS THAT NOT MUCH PRECIPITATION WILL OCCUR ON FRIDAY.
WILL NOT ALTER SLIGHT CHANCE POPS FROM CONSENSUS OF MODELS. SOME
INDICATION THAT AS WARMING KICKS IN ABOVE H9 AHEAD OF THE
TROUGH...LOW-LEVEL MOISTURE MAY REMAIN TRAPPED BENEATH THE INVERSION
OVER MUCH OF CWA RIGHT THROUGH FRIDAY. MAIN IMPACT WILL BE ON TEMPS
THURSDAY THROUGH FRIDAY. DUE TO STRICT TEMPERATURE ADVECTION WOULD
THINK MANY AREAS THURSDAY AND FRIDAY WILL STILL BE ABLE TO CRACK THE
FREEZING MARK.
MODELS NOT AS COLD IN WAKE OF FRONT NEXT WEEKEND AS THEY HAVE SHOWED
LAST COUPLE DAYS. ULTIMATELY MAY END UP BEING DRY NEXT WEEKEND /JUST
HAVE SLIGHT CHANCES IN THERE/ WITH TEMPERATURES SIMILAR TO LATE THIS
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 119 AM EST MON MAR 4 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FCST PERIOD WITH A SURFACE
RIDGE DOMINATING THE WEATHER IN THE NORTHERN GREAT LAKES. ONLY
EXCEPTION WILL BE AT SAW WITH SOME LAKE EFFECT UPSLOPE MVFR CLOUDS
IN FOR THIS MORNING...BEFORE BURNING OFF AGAIN IN THE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EST SUN MAR 3 2013
STRONGEST WINDS THIS WEEK OCCUR MONDAY AFTERNOON THROUGH TUESDAY
OVER FAR WESTERN LAKE SUPERIOR AS LOW PRESSURE SYSTEM MOVES BY JUST
TO THE SOUTH. EAST-NORTHEAST WINDS TO 30 KTS GOOD BET. MAY BE GALE
GUSTS TOWARD THE HEAD OF LK SUPERIOR AND ALONG THE MINNESOTA SHORE
MONDAY NIGHT INTO TUESDAY MORNING DUE TO COASTAL CONVERGENCE. NORTH
WINDS TO 25 KTS CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY
WINDS AND COLDER TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT
TIMES THROUGH WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WEDNESDAY AND THURSDAY AS HIGH PRESSURE CROSSES THE REGION.
SOUTH WINDS TO 25 KTS POSSIBLE THURSDAY NIGHT INTO FRIDAY OUT AHEAD
OF LOW PRESSURE TROUGH. TROUGH MOVES THROUGH FRIDAY NIGHT BUT
WEST-NORTHWEST WINDS IN WAKE OF TROUGH SHOULD STAY BLO 20 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1138 PM CST SUN MAR 3 2013
.UPDATE...
ISSUED AT 930 PM CST SUN MAR 3 2013
GOING FORECAST FOR A THREAT OF A LIGHT WINTRY MIX ACROSS OUR NE
COUNTIES STILL LOOKS ON THE MARK...AS REGIONAL RADAR LOOP HAS BEEN
INDICATING RELATIVELY NARROW BAND OF WAA-INDUCED PRECIP GRADUALLY
WORKING SE FROM CENTRAL IOWA. LATEST RUC AND 00Z NAM ARE STILL
SUGGESTING PTYPE WILL BE MOSTLY SNOW AT ONSET...BUT SHOULD
BECOME MIXED WITH AND TRANSITION TO SLEET AND FREEZING RAIN AS
ELEVATED WARM LAYER DEEPENS OVERNIGHT. FORTUNATELY PRECIP WILL
LIKELY BE SOMEWHAT HIT AND MISS...QUITE LIGHT... AND SHOULD ONLY
LAST AN HOUR OR SO...THEREFORE NO HEADLINES PLANNED ATTM.
ONE CHANGE TO GOING FORECAST WAS TO EXPAND THE SLIGHT CHANCE POPS
FURTHER S INTO THE STL AREA. MID LEVEL ECHO HAS BEEN EXPANDING
FROM BETWEEN IRK AND COU OVER THE LAST HOUR OR SO...AND BELIEVE
THAT SUBTLE INCREASE IN LIFT INTO THE MID MISSISSIPPI VALLEY MAY
BE JUST ENOUGH TO GET SOME PRECIP JUST S OF THE I-70 CORRIDOR.
IN THIS AREA...HAVE KEPT PTYPE AS ALL RAIN.
TRUETT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 301 PM CST SUN MAR 3 2013
FOCUS TONIGHT WILL BE PRECIP CHANCES.
STRONG WAA OVER THE REGION HAS MANAGED TO KEEP CLOUDS IN PLACE
THRU THE DAY. THIS IS ALSO RESPONSIBLE FOR THE AREA OF LIGHT SHSN OVER
ERN MO THAT HAS DEVELOPED OVER THE PAST FEW HOURS. MDLS SHOW
STRONG FORCING OVER THIS REGION THRU THIS AFTERNOON.
HOWEVER...THIS FORCING BECOMES RATHER DIFFUSE THIS EVENING...BUT
HAVE LOW SLIGHT CHANCE POPS THRU EARLY THIS EVENING TO ACCOUNT FOR
THIS. BELIEVE IT WILL MAINTAIN THE CURRENT TRACK TO THE SE AND
PROBABLY DISSIPATE BEFORE IT REACHES SERN PORTIONS OF THE CWA.
LATER TONIGHT...A SEPARATE WAA BAND MAY DEVELOP FAR ENUF TO THE SE
THAT IT WILL IMPACT NRN PORTIONS OF THE CWA. HAVE TRENDED TWD THE
GEM/ECMWF/GFS SOLNS AS THESE MDLS SEEM TO HAVE A BETTER HANDLE ON
THE CURRENT SITUATION. CONTINUE A MIX OF P-TYPES TONIGHT BASED ON
GFS PROGD SOUNDINGS AND UNCERTAINTY IN PLACEMENT OF PRECIP.
BELIEVE BULK OF PRECIP WILL BE SN UNTIL JUST BEFORE SUNRISE WHEN
MDLS WARM MID LVLS ENUF THAT IP OR FZRA WILL BE POSSIBLE.
HOWEVER...THIS IS ALSO THE TIME WHEN PRECIP IS MOST LIKELY. FOR
NOW...HAVE LIGHT ACCUMULATION OF SN/IP AS WELL AS A GLAZING OF
ICE.
&&
.LONG TERM...(MONDAY THROUGH NEXT SUNDAY)
ISSUED AT 334 PM CST SUN MAR 3 2013
(MONDAY THROUGH WEDNESDAY)
THE ONGOING NW/SE ORIENTED BAND OF PRECIPITATION DRIVEN THROUGH LOW
LEVEL WAA AND FRONTOGENTETIC FORCING SHOULD HAVE EITHER EXITED THE
CWA OR BE ON THE FAR FRINGES OF THE SOUTH CENTRAL IL COUNTIES AT
DAYBREAK ON MONDAY. MODEL SOUNDINGS OVERNIGHT TONIGHT THROUGH MONDAY
MORNING SHOW THAT STRONG LOW LEVEL WAA WILL CONTINUOUSLY ERODE THE
COLD AIR AS AN ELEVATED WARM LAYER DEVELOPS. THERMAL PROFILES AT 12Z
WITHIN THE PRECIPITATION THREAT AREA SHOW ONLY A SURFACE-BASED
SUBFREEZING COLD LAYER FROM 1-2KFT DEEP...SUGGESTIVE OF FREEZING
RAIN AND POSSIBLY SLEET AS A PTYPE. BY 15Z THE PRECIPITATION THREAT
APPEARS WELL REMOVED TO THE EAST AND THE ENTIRE LOWER TROP ACROSS
THE REGION IS WARMING. I THINK UNTIL MID-LATE AFTERNOON THERE WILL
JUST BE AN ABUNDANCE OF CLOUDS...BUT AFTER 21Z OR SO THERE COULD BE
SOME SPOTTY RAIN/SHOWERS ACROSS SE MO AND SRN IL AND ACROSS FAR NRN
MO INTO WEST CENTRAL IL. TEMPERATURES REMAIN A TOUGH CALL DUE TO THE
CLOUDS AND EXISTING SNOW COVER AND TEMPERED THEM BACK A BIT FROM
GUIDANCE OVER THE DEEPER SNOW PACK FROM CENTRAL MO THRU WEST CENTRAL
IL WHILE LETTING THEM WARM SUBSTANTIALLY ACROSS SRN MO.
THE BIGGEST ITEM OF INTEREST DURING THIS PERIOD IS THE UPPER LOW
CURRENTLY MOVING INTO THE UPPER ROCKIES. WE HAVE BEEN CAREFULLY
MONITORING THIS POTENT UPPER SYSTEM AND POTENTIAL IMPACTS MONDAY
NIGHT INTO TUESDAY AS IT MOVES THROUGH THE MID MS VALLEY. DESPITE
THE SYSTEM BEING ONSHORE NOW AND APPARENTLY WELL SAMPLED BY THE NOAM
UPPER AIR NETWORK...THERE REMAINS SIGNIFICANT DIFFERENCES WITH
RESPECT TO THE TRACK/POSITION AND EVEN TIMING OF THE UPPER
LOW...WITH POSITION DIFFERENCES ON THE ORDER OF 200 MILES BY 00Z
WED. THERE IS A GENERAL CONSENSUS THAT THE HEAVIEST SNOW BAND WILL
BE FROM NRN IA THRU NRN/CNTRL IL...HOWEVER THE EXTENT OF LIGHT TO
MODERATE SNOW FURTHER TO THE SOUTHWEST AND THRU OUR CWA IS MORE
QUESTIONABLE DUE TO THESE POSITION VARIANCES. THIS FORECAST GIVES
CREDENCE TO THE RANGE OF SOLUTIONS INCLUDING THE MORE SRN POSITIONS
OF THE UKMET AND ECMWF. STRONG CAA AND GUSTY NW WINDS IN THE WAKE
OF THE ASSOCIATED LOW LEVEL/SURFACE CYCLONES SHOULD BRING DEEPENING
COLD AIR FROM NW TO SE ACROSS THE CWA LATE MONDAY NIGHT INTO EARLY
TUESDAY SUPPORTING A CHANGE FROM RAIN TO SNOW. THE PRECIPITATION
THREAT WILL BE A RESULT OF STRONG MID/UPPER LEVEL FORCING ASSOCIATED
WITH THE MID/UPPER LOW AND VORT MAX MOVING TO ITS SOUTH. IN ADDITION
TO THE SNOWFALL WILL BE STRONG AND GUSTY NW WINDS. BY MID EVENING ON
TUESDAY THE SYSTEM AND ANY MEASURABLE SNOWFALL POTENTIAL SHOULD HAVE
EXITED TO THE EAST. CURRENTLY I HAVE SNOWFALL ACCUMULATIONS RANGING
FROM 2-3 INCHES IN NE MO AND WEST CENTRAL IL TAPERING TO JUST OVER
AN INCH THRU METRO ST LOUIS. THESE AMOUNTS WILL BE A BIT ON THE
LIGHT SIDE IF THE ECMWF AND UKMET PAN OUT. HIGH PRESSURE WILL THEN
BUILD INTO THE AREA LATE WEDNESDAY AND DOMINATE ON WED NIGHT.
(THURSDAY THROUGH SUNDAY)
BIG PATTERN CHANGE TO EVOLVE DURING THIS PERIOD WITH A TRANSITION TO
AN AMPLIFIED BUT PROGRESSIVE SPLIT FLOW REGIME. THE UPPER LOW/TROF
EXITS QUICKLY EASTWARD INTO THE ATLANTIC BY LATE THURSDAY WITH LARGE
HEIGHT RISES ALOFT IN ITS WAKE AS AN UPPER RIDGE BUILDS INTO THE MS
VALLEY AND AN UPPER LOW/TROF DIGS INTO THE WEST COAST. IN RESPONSE
WE SHOULD SEE A NICE WARM-UP IN TEMPERATURES TO ABOVE AVERAGE LEVELS
AS WE GET INTO SOUTHERLY RETURN FLOW AND H85 TEMPERATURES RISE TO +6
TO +10 DEGC BY LATE FRIDAY. THE UPPER RIDGE THEN SHIFTS INTO THE
EASTERN U.S. DURING THE WEEKEND AS THE UPPER LOW/TROF MOVES INTO THE
SWRN U.S...WHILE A THE SRN EXTENSION OF AN UPPER TROF/LOW OVER
CANADA TRANSLATES ACROSS THE UPPER MS VALLEY INTO THE NERN U.S. THIS
LATER FEATURE WILL RESULT IN AN EAST-WEST ORIENTED COLD FRONT
DIPPING DOWN INTO THE REGION AND BI-SECTING THE CWA. THE PRESENCE OF
THE FRONTAL BOUNDARY COMBINED WITH INCREASING MOISTURE AND LIFT IN
ADVANCE OF THE SWRN U.S. SYSTEM SHOULD BRING AN INCREASING THREAT OF
RAIN THRU THE WEEKEND.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1138 PM CST SUN MAR 3 2013
WAA PCPN HAS DEVELOPED OVER IOWA AND CONTINUES TO SPREAD SOUTHEAST
INTO EASTERN MO/WEST CENTRAL IL. COVERAGE WILL BE SPOTTY. FOR NOW
JUST HAVE TEMPO GROUPS AT KUIN AND METRO AREA TAFS THROUGH 10Z MONDAY.
AS FOR PCPN TYPE...KUIN IS BELOW FREEZING SO WILL SEE MOSTLY LIGHT
FREEZING RAIN...WHILE METRO AREA TO REMAIN ABOVE FREEZING WITH
JUST LIGHT RAIN. CIGS/VSBYS TO REMAIN VFR WITH THIS ACTIVITY.
OTHERWISE...SOUTHEAST WINDS TO PICKUP TO BETWEEN 10 AND 15 KTS
BEFORE BACKING TO THE EAST AND DIMINISHING JUST A BIT BY LATE THIS
AFTERNOON. WILL HAVE BETTER CHANCES OF PCPN WITH MAIN SYSTEM AFTER
00Z TUESDAY WITH IT STARTING OFF AS ALL RAIN. CIGS AND VSBYS TO
DIP DOWN TO MVFR WITH ONSET OF PCPN. PCPN TO CHANGE OVER AND/OR
MIX WITH SNOW...BUT THIS IS BEYOND CURRENT VALID TAF PERIOD.
SPECIFICS FOR KSTL...WAA PCPN HAS DEVELOPED OVER IOWA AND CONTINUES
TO SPREAD SOUTHEAST INTO EASTERN MO/WEST CENTRAL IL. COVERAGE
WILL BE SPOTTY. FOR NOW JUST HAVE TEMPO GROUP AT KSTL THROUGH 09Z MONDAY.
AS FOR PCPN TYPE...METRO AREA TO REMAIN ABOVE FREEZING WITH JUST
LIGHT RAIN. CIGS/VSBYS TO REMAIN VFR WITH THIS ACTIVITY.
OTHERWISE...SOUTHEAST WINDS TO PICKUP TO BETWEEN 10 AND 15 KTS
BEFORE BACKING TO THE EAST AND DIMINISHING JUST A BIT BY 23Z MONDAY.
WILL HAVE BETTER CHANCES OF PCPN WITH MAIN SYSTEM AFTER 03Z
TUESDAY WITH IT STARTING OFF AS ALL RAIN. CIGS AND VSBYS TO DIP
DOWN TO MVFR WITH ONSET OF PCPN. PCPN TO POSSIBLY MIX WITH
SNOW...BUT HARD TO PIN THIS DOWN...SO JUST HAVE RAIN MENTION IN
TAF.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1115 PM CST SUN MAR 3 2013
.SYNOPSIS...
ISSUED AT 335 PM CST SUN MAR 3 2013
H5 ANALYSIS FROM THIS MORNING HAS A BROAD TROUGH OF LOW PRESSURE
OVER THE EASTERN SEA BOARD. RIDGING EXTENDED FROM THE FOUR CORNERS
NWD INTO EASTERN MT. FURTHER WEST...A STRONG SHORTWAVE TROUGH OF LOW
PRESSURE WAS TRACKING EAST INTO THE NORTHERN ROCKIES WITH 180 METER
HT FALLS NOTED AT SPOKANE WASHINGTON AND 130 METER FALLS AT GREAT
FALLS MT. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NWRN
NEBRASKA...WITH A FRONT EXTENDING SSE INTO SOUTH CENTRAL NEBRASKA. LIKE
YESTERDAY...A LARGE SPREAD IN TEMPERATURES WERE NOTED ACROSS
NEBRASKA...WITH 2 PM CST TEMPS RANGING FROM 38 AT OMAHA...TO 67
AT IMPERIAL.
&&
.UPDATE...
ISSUED AT 1013 PM CST SUN MAR 3 2013
HIGH WINDS RIPPED THROUGH RAPID CITY SD THIS PAST HOUR WITH A 66 MPH
GUST. THE HRRR SUGGESTS THE CONVECTION AND WIND GUSTS WILL WEAKEN
BEFORE THE FRONT REACHES NRN NEB AROUND 5Z-6Z.
A NEW WIND FCST IS OUT FOR MONDAY AND MONDAY NIGHT AND WINDS ARE
SLIGHTLY WEAKER...MAYBE 5 MPH.
NO DISCERNIBLE CHANGES TO THE TEMPERATURES AND RAIN/SNOW CHANCES OVERNIGHT
THROUGH MONDAY NIGHT.
UPDATE ISSUED AT 702 PM CST SUN MAR 3 2013
THE PACIFIC FRONT IS RIPPING APART NORTHEAST WY THIS EVENING WITH
A GUST TO 66 MPH AT BUFFALO. THE FRONT WILL ENTER WRN AND NCNTL
NEB TONIGHT. GUSTS SHOULD REACH 40 MPH...PERHAPS STRONGER.
A FEW COUNTIES HAVE BEEN ADDED TO THE WIND ADZY AS BLENDS OF
GEM...NAM...SREF AND MET/MAV SUGGESTED STRONGER WINDS. GIVEN THE
EVENTS THIS AFTN/EVENING ACROSS THE NRN HIGH PLAINS THIS ADDITION
SHOULD WORK. THE REST OF THE FCST IS VERY SIMILAR TO THE PREVIOUS.
RAIN AND SNOW SHOWERS ARE DEVELOPING ALONG THE PACIFIC FRONT AND
THESE SHOULD WORK THROUGH NRN NEB TONIGHT.
GIVEN THE UNCERTAINTIES OF THE FCST OVERNIGHT. THE BEST APPROACH
TO THE ONGOING HIGH WIND EVENT ACROSS THE NRN HIGH PLAINS WOULD
BE TO WATCH OBSERVATIONS CLOSELY FOR SIGNS OF WEAKENING. THE PV1.5
SFC IS EXPECTED TO REMAIN ON AN EASTERLY COURSE AFFECTING WRN SD
AND ND TONIGHT. THUS IT IS NOT SYNOPTICALLY EVIDENT THAT STRONG
OR HIGH WINDS WILL DEVELOP ACROSS WRN AND NCNTL NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH WINDS AND LIGHT
PRECIPITATION CHANCES OVER NORTHERN NEBRASKA.
THE SHORTWAVE TROUGH OVER WESTERN MONTANA WILL PUSH INTO THE DAKOTAS
THROUGH THE DAY MONDAY...BRINGING A DRAMATIC CHANGE TO THE LOCAL
WEATHER. AT THE SURFACE...THE FRONTAL BOUNDARY WILL STAY NEARLY
STATIONARY FROM CENTRAL SOUTH DAKOTA THROUGH SOUTH CENTRAL NEBRASKA
THROUGH MONDAY MORNING...BEFORE PUSHING EASTWARD BY THE END OF THE
DAY.
LOOKING AT PRECIPITATION WITH THE SYSTEM...THE BEST MOISTURE WILL
STAY UP ACROSS THE DAKOTAS WHERE THE SURFACE LOW WILL PASS. BUT WITH
THE LOCATION OF THE FRONT BEING OVER NORTH CENTRAL NEBRASKA...MAY
HAVE ENOUGH LIFT AND MOISTURE CONVERGENCE TO NEED SOME CHANCES FOR
PRECIPITATION OVER THE NORTH CENTRAL COUNTIES TONIGHT AND MONDAY
MORNING. THEN AS THE COLD FRONT MOVES THROUGH TONIGHT COULD GET A
BIT OF ENHANCED LIFT TO GIVE SOME LIGHT PRECIPITATION. WITH ONLY
LIMITED MOISTURE AND NO STRONG SIGNALS FOR GOOD PRECIPITATION
DEVELOPMENT LOCALLY...BELIEVE ANYTHING WILL BE VERY LIGHT...WITH
CHANCES FOR MEASURABLE PRECIPITATION BEING LOW. THE OTHER CONCERN IS
PRECIPITATION TYPE. THERE IS STRONG COLD AIR ADVECTION COMING BEHIND
THE FRONT TONIGHT AT 850MB...BUT AT THE SURFACE...TEMPERATURES DON/T
COOL REAL FAST. SO...WITH CURRENT TEMPERATURES IN THE 40S...50S AND
60S...WILL NEED SOME TIME TO GET THE COLDER AIR ACROSS THE AREA AND
KEPT A RAIN/SNOW MIX IN THE FORECAST THROUGH 09Z. AFTER
09Z...NORTHWEST NEBRASKA SHOULD HAVE COOLED ENOUGH FOR PRECIPITATION
TO BE SNOW...HOWEVER CLOSER TO THE FRONT OVER NORTH CENTRAL
NEBRASKA...FORECAST SOUNDINGS WERE SHOWING A SIGNAL FOR FREEZING
RAIN OR FREEZING DRIZZLE FOR A SHORT PERIOD. AS IT LOOKS LIKE THIS
WOULD OCCUR FOR A VERY SHORT PERIOD...NOT EXPECTING MUCH IF ANY ICE
ACCUMULATION...SO THREAT FOR HAZARDOUS TRAVEL SHOULD BE LOW. AFTER
12Z...TEMPERATURE PROFILES LOOK LIKE PRECIPITATION SHOULD CHANGE OVER
TO SNOW EVERYWHERE. THEN AS SURFACE TEMPERATURES WARM A BIT DURING
THE DAY...MAY AGAIN GET A CHANGEOVER TO RAIN/SNOW MIX OR RAIN.
FOR WINDS...AS THE COLD FRONT MOVES THROUGH TONIGHT...WITH HAVE
PRETTY SIGNIFICANT PRESSURE RISES SO HAVE INCREASED WINDS TONIGHT.
THE STRONGER WINDS ARE EXPECTED TO DEVELOP AROUND NOON-TIME MONDAY
ACROSS THE PANHANDLE AS THE PRESSURE GRADIENT TIGHTENS...COLD AIR
ADVECTION STRENGTHENS AND A DECENT PV ANOMALY MOVES ACROSS THE AREA.
AS THIS OCCURS...THE BOUNDARY LAYER SHOULD MIX TO AT LEAST
800MB...AND WITH UNIDIRECTIONAL WINDS GOING UPWARD...SHOULDN/T HAVE
A PROBLEM BRINGING DOWN THE STRONGER WINDS FROM ALOFT. JUST HOW
STRONG THEY WILL BE REMAINS A BIT OF A QUESTION. AS IS TYPICAL...THE
GFS AND MAV GUIDANCE IS STRONGER WITH THE WIND SPEEDS...WHILE THE
NAM AND MET GUIDANCE IS QUITE A BIT LESS. THE SIGNAL LOOKS GOOD
ENOUGH FOR AT LEAST MARGINAL WIND ADVISORY SPEEDS ACROSS THE
PANHANDLE STARTING AROUND MID-DAY...THEN TRANSITIONING ACROSS NORTH
CENTRAL NEBRASKA LATER INTO THE AFTERNOON AND EVENING. SO...HAVE
ISSUED A WIND ADVISORY FOR THOSE AREAS FOR MONDAY AFTERNOON INTO
MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
MONDAY NIGHT THROUGH WEDNESDAY...WINDS WILL BE THE MAIN
FORECAST CONCERN FROM MONDAY NIGHT INTO EARLY TUESDAY...THEN
TEMPERATURES ON TUESDAY AND WEDNESDAY AS AN ARCTIC AIRMASS PUSHES
SOUTH INTO THE CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY.
STRONG NORTHERLY WINDS WILL TRANSITION EAST FROM NORTHWESTERN
NEBRASKA MONDAY EVENING AS THE ARCTIC COLD FRONT PUSHES INTO NORTH
CENTRAL...THEN NORTHEASTERN NEBRASKA. LOW LEVEL COLD AIR ADVECTION
AND SURFACE PRESSURE RISES ARE MOST PRONOUNCED ACROSS THE N CENTRAL
CWA MONDAY EVENING WITH THE BEST WIND POTENTIAL IN THESE AREAS. GFS
BUFKIT SOUNDINGS ACROSS NORTHERN NEBRASKA...SUPPORT SUSTAINED WINDS
OF 30 TO 40 MPH...WITH GUSTS TO 50 MPH MONDAY EVENING...WHILE THE
NAM BUFKIT SOUNDINGS ARE ABOUT 5 TO 10 MPH SLOWER. WILL UTILIZE A
50/50 BLEND BETWEEN THE MAV AND MET WIND SPEEDS WHICH YIELDS WIND
SPEEDS OF 25 TO 35 MPH WITH GUSTS TO 45 MPH. DECIDED TO CARRY OVER
THE WIND ADVISORY INTO NORTH CENTRAL NEBRASKA THROUGH TUESDAY
MORNING. BY 12Z TUESDAY...LOW LEVEL COLD AIR ADVECTION WILL COME TO
AN END...WHILE THE CORE OF 30+KT 500 METER AGL WINDS...SHIFTS EAST
INTO NERN NEBRASKA. FURTHER WEST...WILL EXPIRE THE WIND ADVISORY
AROUND MIDNIGHT...AS LOW LEVEL CAA ENDS AND PRESSURE RISES END.
WINDS WILL DIMINISH FURTHER ON TUESDAY AS COLD ARCTIC HIGH PRESSURE
BUILDS INTO THE CENTRAL AND NORTHERN PLAINS. BASED ON H85
TEMPS...HIGHS TUESDAY WILL VARY WIDELY ACROSS THE FORECAST
AREA...WITH READINGS AROUND 30 IN THE NORTHEAST...TO THE LOWER 40S
IN SWRN NEBRASKA. HIGH PRESSURE WILL TRACK EAST ON TUESDAY NIGHT
WITH INCREASING SRLY WINDS FOR WEDNESDAY. WARMER TEMPERATURES WILL
BEGIN TO WORK INTO WESTERN NEBRASKA ON WEDNESDAY...HOWEVER...COLD
TEMPERATURES WILL REMAIN AT IN THE EASTERN CWA WITH HIGHS AROUND 40
FOR KONL...AND 42 FOR KANW. READINGS WILL BE IN THE LOWER 50S ACROSS
SWRN NEBRASKA AND THE EASTERN PANHANDLE. BASED ON FCST 500 METER
WINDS...SURFACE WIND SPEEDS ARE EXPECTED TO BE WELL BELOW ADVISORY
CRITERIA WEDS AFTERNOON.
WEDNESDAY NIGHT THROUGH SUNDAY...COLD AIR WILL SLIDE
EAST WITH THE HIGH WEDNESDAY NIGHT...AND SURFACE LOW PRESSURE WILL
DEEPEN OVER EASTERN COLORADO. SRLY WINDS WILL INCREASE...ALONG WITH
TEMPERATURES AS THE ARCTIC AIR MASS SHIFTS EAST OF THE AREA. FCST
H85 TEMPS WILL INCREASE TO 8 TO 12 C THURSDAY AFTERNOON AHEAD OF A
APPG COLD FRONT. THE COMBINATION OF THE APPG COLD FRONT...SRLY
WINDS...AND RIDGING ALOFT...WILL RESULT IN HIGHS IN THE 50S TO LOWER
60S THURSDAY. AFTER ONE DAY OF WARM TEMPERATURES...MUCH COOLER
TEMPERATURES AND THE POTENTIAL FOR A POTENT WINTER STORM...WILL
BEGIN TO PUSH ACROSS SRN ROCKIES ONTO THE CENTRAL AND SRN PLAINS
FRIDAY NIGHT INTO SATURDAY. SOME TRACK DIFFERENCES EXIST BETWEEN THE
GFS AND EC MODEL RUNS THIS MORNING. THE GFS REMAINS SOUTH...WITH THE
ECMWF BEING FURTHER NORTH. BOTH SOLUTIONS PUSH COLD FRONT INTO THE
FORECAST AREA EITHER FRIDAY NIGHT OR SATURDAY DEPENDING ON MODEL
CHOICE. THE RESULTANT AIRMASS BEHIND THE FRONT WILL BE A SHALLOW SUB
FREEZING LAYER...WITH DECENT MID LEVEL ASCENT NOTED ABOVE THIS
LAYER. WOULDN`T BE SURPRISED TO SEE A MIX OF PCPN ACROSS THE NORTH
FOR FRIDAY INTO FRIDAY NIGHT. HOWEVER...GIVEN THE MODEL DIFFERENCES
WITH THE TIMING OF THE FRONT...DECIDED TO WORD PRECIPITATION MENTION
AS RAIN OR SNOW ATTM. THIS WILL CARRY OVER INTO THE WEEKEND WITH
HIGHS IN THE 30S AND LOWS IN THE 20S. ATTM...THE EXTENDED BEYOND
THURSDAY REMAINS A LOW CONFIDENCE FCST...IN PARTICULAR PRECIPITATION
TYPE...AS POOR MODEL AGREEMENT IS NOTED. NO DOUBT...WE COULD SEE
SOME PRECIPITATION NEXT WEEKEND GIVEN THE CURRENT EC AND GFS
SOLNS...AND CHANCE POPS REFLECT THAT IN THE CURRENT FCST. BASED ON
EITHER SOLUTION...WE COULD BE DEALING WITH LIGHT PRECIPITATION...OR
A SIGNIFICANT SNOW STORM (12Z ECMWF SOLUTION). WILL NEED TO MONITOR
THIS CLOSELY OVER THE NEXT FEW DAYS AS WE GRAVITATE TOWARD
MIDWEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM CST SUN MAR 3 2013
A STRONG PACIFIC FRONT...CURRENTLY BETWEEN KRAP...KIEN AND KPHP WILL MOVE
THROUGH THE FCST AREA OVERNIGHT PRODUCING A BRIEF PERIOD OF STRONG WINDS
AND MVFR.
OTHERWISE VFR IS EXPECTED MONDAY AND MONDAY EVENING. WINDS WILL
INCREASE TO 32028G40KT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CST /11 AM MST/ MONDAY TO MIDNIGHT CST
/11 PM MST/ MONDAY NIGHT FOR NEZ004-022>024-035-036-056>058-069-
094.
WIND ADVISORY FROM 3 PM MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR
NEZ059-070.
WIND ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
NEZ005>010-025>029-037-038.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1019 PM CST SUN MAR 3 2013
.SYNOPSIS...
ISSUED AT 335 PM CST SUN MAR 3 2013
H5 ANALYSIS FROM THIS MORNING HAS A BROAD TROUGH OF LOW PRESSURE
OVER THE EASTERN SEA BOARD. RIDGING EXTENDED FROM THE FOUR CORNERS
NWD INTO EASTERN MT. FURTHER WEST...A STRONG SHORTWAVE TROUGH OF LOW
PRESSURE WAS TRACKING EAST INTO THE NORTHERN ROCKIES WITH 180 METER
HT FALLS NOTED AT SPOKANE WASHINGTON AND 130 METER FALLS AT GREAT
FALLS MT. AT THE SURFACE...LOW PRESSURE WAS NOTED OVER NWRN
NEBRASKA...WITH A FRONT EXTENDING SSE INTO SOUTH CENTRAL NEBRASKA. LIKE
YESTERDAY...A LARGE SPREAD IN TEMPERATURES WERE NOTED ACROSS
NEBRASKA...WITH 2 PM CST TEMPS RANGING FROM 38 AT OMAHA...TO 67
AT IMPERIAL.
&&
.UPDATE...
ISSUED AT 1013 PM CST SUN MAR 3 2013
HIGH WINDS RIPPED THROUGH RAPID CITY SD THIS PAST HOUR WITH A 66 MPH
GUST. THE HRRR SUGGESTS THE CONVECTION AND WIND GUSTS WILL WEAKEN
BEFORE THE FRONT REACHES NRN NEB AROUND 5Z-6Z.
A NEW WIND FCST IS OUT FOR MONDAY AND MONDAY NIGHT AND WINDS ARE
SLIGHTLY WEAKER...MAYBE 5 MPH.
NO DISCERNIBLE CHANGES TO THE TEMPERATURES AND RAIN/SNOW CHANCES OVERNIGHT
THROUGH MONDAY NIGHT.
UPDATE ISSUED AT 702 PM CST SUN MAR 3 2013
THE PACIFIC FRONT IS RIPPING APART NORTHEAST WY THIS EVENING WITH
A GUST TO 66 MPH AT BUFFALO. THE FRONT WILL ENTER WRN AND NCNTL
NEB TONIGHT. GUSTS SHOULD REACH 40 MPH...PERHAPS STRONGER.
A FEW COUNTIES HAVE BEEN ADDED TO THE WIND ADZY AS BLENDS OF
GEM...NAM...SREF AND MET/MAV SUGGESTED STRONGER WINDS. GIVEN THE
EVENTS THIS AFTN/EVENING ACROSS THE NRN HIGH PLAINS THIS ADDITION
SHOULD WORK. THE REST OF THE FCST IS VERY SIMILAR TO THE PREVIOUS.
RAIN AND SNOW SHOWERS ARE DEVELOPING ALONG THE PACIFIC FRONT AND
THESE SHOULD WORK THROUGH NRN NEB TONIGHT.
GIVEN THE UNCERTAINTIES OF THE FCST OVERNIGHT. THE BEST APPROACH
TO THE ONGOING HIGH WIND EVENT ACROSS THE NRN HIGH PLAINS WOULD
BE TO WATCH OBSERVATIONS CLOSELY FOR SIGNS OF WEAKENING. THE PV1.5
SFC IS EXPECTED TO REMAIN ON AN EASTERLY COURSE AFFECTING WRN SD
AND ND TONIGHT. THUS IT IS NOT SYNOPTICALLY EVIDENT THAT STRONG
OR HIGH WINDS WILL DEVELOP ACROSS WRN AND NCNTL NEBRASKA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
FORECAST CONCERNS THROUGH THIS PERIOD DEAL WITH WINDS AND LIGHT
PRECIPITATION CHANCES OVER NORTHERN NEBRASKA.
THE SHORTWAVE TROUGH OVER WESTERN MONTANA WILL PUSH INTO THE DAKOTAS
THROUGH THE DAY MONDAY...BRINGING A DRAMATIC CHANGE TO THE LOCAL
WEATHER. AT THE SURFACE...THE FRONTAL BOUNDARY WILL STAY NEARLY
STATIONARY FROM CENTRAL SOUTH DAKOTA THROUGH SOUTH CENTRAL NEBRASKA
THROUGH MONDAY MORNING...BEFORE PUSHING EASTWARD BY THE END OF THE
DAY.
LOOKING AT PRECIPITATION WITH THE SYSTEM...THE BEST MOISTURE WILL
STAY UP ACROSS THE DAKOTAS WHERE THE SURFACE LOW WILL PASS. BUT WITH
THE LOCATION OF THE FRONT BEING OVER NORTH CENTRAL NEBRASKA...MAY
HAVE ENOUGH LIFT AND MOISTURE CONVERGENCE TO NEED SOME CHANCES FOR
PRECIPITATION OVER THE NORTH CENTRAL COUNTIES TONIGHT AND MONDAY
MORNING. THEN AS THE COLD FRONT MOVES THROUGH TONIGHT COULD GET A
BIT OF ENHANCED LIFT TO GIVE SOME LIGHT PRECIPITATION. WITH ONLY
LIMITED MOISTURE AND NO STRONG SIGNALS FOR GOOD PRECIPITATION
DEVELOPMENT LOCALLY...BELIEVE ANYTHING WILL BE VERY LIGHT...WITH
CHANCES FOR MEASURABLE PRECIPITATION BEING LOW. THE OTHER CONCERN IS
PRECIPITATION TYPE. THERE IS STRONG COLD AIR ADVECTION COMING BEHIND
THE FRONT TONIGHT AT 850MB...BUT AT THE SURFACE...TEMPERATURES DON/T
COOL REAL FAST. SO...WITH CURRENT TEMPERATURES IN THE 40S...50S AND
60S...WILL NEED SOME TIME TO GET THE COLDER AIR ACROSS THE AREA AND
KEPT A RAIN/SNOW MIX IN THE FORECAST THROUGH 09Z. AFTER
09Z...NORTHWEST NEBRASKA SHOULD HAVE COOLED ENOUGH FOR PRECIPITATION
TO BE SNOW...HOWEVER CLOSER TO THE FRONT OVER NORTH CENTRAL
NEBRASKA...FORECAST SOUNDINGS WERE SHOWING A SIGNAL FOR FREEZING
RAIN OR FREEZING DRIZZLE FOR A SHORT PERIOD. AS IT LOOKS LIKE THIS
WOULD OCCUR FOR A VERY SHORT PERIOD...NOT EXPECTING MUCH IF ANY ICE
ACCUMULATION...SO THREAT FOR HAZARDOUS TRAVEL SHOULD BE LOW. AFTER
12Z...TEMPERATURE PROFILES LOOK LIKE PRECIPITATION SHOULD CHANGE OVER
TO SNOW EVERYWHERE. THEN AS SURFACE TEMPERATURES WARM A BIT DURING
THE DAY...MAY AGAIN GET A CHANGEOVER TO RAIN/SNOW MIX OR RAIN.
FOR WINDS...AS THE COLD FRONT MOVES THROUGH TONIGHT...WITH HAVE
PRETTY SIGNIFICANT PRESSURE RISES SO HAVE INCREASED WINDS TONIGHT.
THE STRONGER WINDS ARE EXPECTED TO DEVELOP AROUND NOON-TIME MONDAY
ACROSS THE PANHANDLE AS THE PRESSURE GRADIENT TIGHTENS...COLD AIR
ADVECTION STRENGTHENS AND A DECENT PV ANOMALY MOVES ACROSS THE AREA.
AS THIS OCCURS...THE BOUNDARY LAYER SHOULD MIX TO AT LEAST
800MB...AND WITH UNIDIRECTIONAL WINDS GOING UPWARD...SHOULDN/T HAVE
A PROBLEM BRINGING DOWN THE STRONGER WINDS FROM ALOFT. JUST HOW
STRONG THEY WILL BE REMAINS A BIT OF A QUESTION. AS IS TYPICAL...THE
GFS AND MAV GUIDANCE IS STRONGER WITH THE WIND SPEEDS...WHILE THE
NAM AND MET GUIDANCE IS QUITE A BIT LESS. THE SIGNAL LOOKS GOOD
ENOUGH FOR AT LEAST MARGINAL WIND ADVISORY SPEEDS ACROSS THE
PANHANDLE STARTING AROUND MID-DAY...THEN TRANSITIONING ACROSS NORTH
CENTRAL NEBRASKA LATER INTO THE AFTERNOON AND EVENING. SO...HAVE
ISSUED A WIND ADVISORY FOR THOSE AREAS FOR MONDAY AFTERNOON INTO
MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 335 PM CST SUN MAR 3 2013
MONDAY NIGHT THROUGH WEDNESDAY...WINDS WILL BE THE MAIN
FORECAST CONCERN FROM MONDAY NIGHT INTO EARLY TUESDAY...THEN
TEMPERATURES ON TUESDAY AND WEDNESDAY AS AN ARCTIC AIRMASS PUSHES
SOUTH INTO THE CENTRAL PLAINS AND UPPER MISSISSIPPI VALLEY.
STRONG NORTHERLY WINDS WILL TRANSITION EAST FROM NORTHWESTERN
NEBRASKA MONDAY EVENING AS THE ARCTIC COLD FRONT PUSHES INTO NORTH
CENTRAL...THEN NORTHEASTERN NEBRASKA. LOW LEVEL COLD AIR ADVECTION
AND SURFACE PRESSURE RISES ARE MOST PRONOUNCED ACROSS THE N CENTRAL
CWA MONDAY EVENING WITH THE BEST WIND POTENTIAL IN THESE AREAS. GFS
BUFKIT SOUNDINGS ACROSS NORTHERN NEBRASKA...SUPPORT SUSTAINED WINDS
OF 30 TO 40 MPH...WITH GUSTS TO 50 MPH MONDAY EVENING...WHILE THE
NAM BUFKIT SOUNDINGS ARE ABOUT 5 TO 10 MPH SLOWER. WILL UTILIZE A
50/50 BLEND BETWEEN THE MAV AND MET WIND SPEEDS WHICH YIELDS WIND
SPEEDS OF 25 TO 35 MPH WITH GUSTS TO 45 MPH. DECIDED TO CARRY OVER
THE WIND ADVISORY INTO NORTH CENTRAL NEBRASKA THROUGH TUESDAY
MORNING. BY 12Z TUESDAY...LOW LEVEL COLD AIR ADVECTION WILL COME TO
AN END...WHILE THE CORE OF 30+KT 500 METER AGL WINDS...SHIFTS EAST
INTO NERN NEBRASKA. FURTHER WEST...WILL EXPIRE THE WIND ADVISORY
AROUND MIDNIGHT...AS LOW LEVEL CAA ENDS AND PRESSURE RISES END.
WINDS WILL DIMINISH FURTHER ON TUESDAY AS COLD ARCTIC HIGH PRESSURE
BUILDS INTO THE CENTRAL AND NORTHERN PLAINS. BASED ON H85
TEMPS...HIGHS TUESDAY WILL VARY WIDELY ACROSS THE FORECAST
AREA...WITH READINGS AROUND 30 IN THE NORTHEAST...TO THE LOWER 40S
IN SWRN NEBRASKA. HIGH PRESSURE WILL TRACK EAST ON TUESDAY NIGHT
WITH INCREASING SRLY WINDS FOR WEDNESDAY. WARMER TEMPERATURES WILL
BEGIN TO WORK INTO WESTERN NEBRASKA ON WEDNESDAY...HOWEVER...COLD
TEMPERATURES WILL REMAIN AT IN THE EASTERN CWA WITH HIGHS AROUND 40
FOR KONL...AND 42 FOR KANW. READINGS WILL BE IN THE LOWER 50S ACROSS
SWRN NEBRASKA AND THE EASTERN PANHANDLE. BASED ON FCST 500 METER
WINDS...SURFACE WIND SPEEDS ARE EXPECTED TO BE WELL BELOW ADVISORY
CRITERIA WEDS AFTERNOON.
WEDNESDAY NIGHT THROUGH SUNDAY...COLD AIR WILL SLIDE
EAST WITH THE HIGH WEDNESDAY NIGHT...AND SURFACE LOW PRESSURE WILL
DEEPEN OVER EASTERN COLORADO. SRLY WINDS WILL INCREASE...ALONG WITH
TEMPERATURES AS THE ARCTIC AIR MASS SHIFTS EAST OF THE AREA. FCST
H85 TEMPS WILL INCREASE TO 8 TO 12 C THURSDAY AFTERNOON AHEAD OF A
APPG COLD FRONT. THE COMBINATION OF THE APPG COLD FRONT...SRLY
WINDS...AND RIDGING ALOFT...WILL RESULT IN HIGHS IN THE 50S TO LOWER
60S THURSDAY. AFTER ONE DAY OF WARM TEMPERATURES...MUCH COOLER
TEMPERATURES AND THE POTENTIAL FOR A POTENT WINTER STORM...WILL
BEGIN TO PUSH ACROSS SRN ROCKIES ONTO THE CENTRAL AND SRN PLAINS
FRIDAY NIGHT INTO SATURDAY. SOME TRACK DIFFERENCES EXIST BETWEEN THE
GFS AND EC MODEL RUNS THIS MORNING. THE GFS REMAINS SOUTH...WITH THE
ECMWF BEING FURTHER NORTH. BOTH SOLUTIONS PUSH COLD FRONT INTO THE
FORECAST AREA EITHER FRIDAY NIGHT OR SATURDAY DEPENDING ON MODEL
CHOICE. THE RESULTANT AIRMASS BEHIND THE FRONT WILL BE A SHALLOW SUB
FREEZING LAYER...WITH DECENT MID LEVEL ASCENT NOTED ABOVE THIS
LAYER. WOULDN`T BE SURPRISED TO SEE A MIX OF PCPN ACROSS THE NORTH
FOR FRIDAY INTO FRIDAY NIGHT. HOWEVER...GIVEN THE MODEL DIFFERENCES
WITH THE TIMING OF THE FRONT...DECIDED TO WORD PRECIPITATION MENTION
AS RAIN OR SNOW ATTM. THIS WILL CARRY OVER INTO THE WEEKEND WITH
HIGHS IN THE 30S AND LOWS IN THE 20S. ATTM...THE EXTENDED BEYOND
THURSDAY REMAINS A LOW CONFIDENCE FCST...IN PARTICULAR PRECIPITATION
TYPE...AS POOR MODEL AGREEMENT IS NOTED. NO DOUBT...WE COULD SEE
SOME PRECIPITATION NEXT WEEKEND GIVEN THE CURRENT EC AND GFS
SOLNS...AND CHANCE POPS REFLECT THAT IN THE CURRENT FCST. BASED ON
EITHER SOLUTION...WE COULD BE DEALING WITH LIGHT PRECIPITATION...OR
A SIGNIFICANT SNOW STORM (12Z ECMWF SOLUTION). WILL NEED TO MONITOR
THIS CLOSELY OVER THE NEXT FEW DAYS AS WE GRAVITATE TOWARD
MIDWEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 524 PM CST SUN MAR 3 2013
A POWERFUL PACIFIC COLD FRONT...CURRENTLY MOVING THROUGH SERN
MT...WILL APPROACH KVTN AROUND 07Z-09Z. THE FRONT HAS THE
POTENTIAL TO PRODUCE STRONG WIND GUSTS AND MVFR AS IT SWEEPS THE FCST
AREA OVERNIGHT. THE HRRR MODEL INDICATES THE FRONT WILL HIT KVTN
AROUND 07Z AND PRODUCE WIND GUSTS OVER 50KT SO WE WILL BE
MONITORING THE FRONT AS IT MOVES THROUGH WRN SD THIS EVENING.
OTHERWISE VFR IS EXPECTED MONDAY. WINDS ARE EXPECTED TO INCREASE
T0 31028G42KT DURING THE LATE MORNING WEST...AND DURING THE AFTN
EAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON CST /11 AM MST/ MONDAY TO MIDNIGHT CST
/11 PM MST/ MONDAY NIGHT FOR NEZ004-022>024-035-036-056>058-069-
094.
WIND ADVISORY FROM 3 PM MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR
NEZ059-070.
WIND ADVISORY FROM 3 PM MONDAY TO 6 AM CST TUESDAY FOR
NEZ005>010-025>029-037-038.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...BROOKS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1230 AM EST MON MAR 4 2013
.SYNOPSIS...
SNOW SHOWERS TAPERING OFF AS UPPER LEVEL LOW LOSES ITS GRIP
OVERNIGHT. HIGH PRESSURE CROSSES MONDAY. STRENGTHENING LOW PRESSURE
SYSTEM CROSSES TUESDAY THROUGH WEDNESDAY. DRIER THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
SEND A QUICK UPDATE TO ADJUST CLOUD COVER PER SFC OBS AND
SATELLITE IMAGES SHOWING IMPROVING CLOUD COVER HIGHER THAN
EXPECTED. AREAS OF CLEARING OVER OH WILL GRADUALLY MOVE OVER
SOUTHEAST OH AND WV FROM WEST TO EAST THROUGH MONDAY MORNING.
POPULATED NEW RAP HOURLY WINDS WEAKER THAN EXPECTED PER WEAKER
PRESSURE GRADIENT FROM A BUILDING HIGH PRESSURE EXTENDING FROM THE
SOUTHEAST STATES...NORTH ACROSS THE OH VALLEY INTO THE GREAT
LAKES. KEPT LOW CHANCE POPS AND TEMPERATURES ARE THEY REMAIN ON
TRACK. EXPECTING LIGHT SNOW OR FLURRIES MAINLY EAST HALF OF THE
CWA UNDER MID LEVEL DECK...TO MOVE EAST DURING THE PREDAWN HOURS.
PREVIOUS DISCUSSION BELOW...
930 PM UPDATE...
FCST REMAINS ON TRACK.
630 PM UPDATE...
FCST LARGELY ON TRACK OTHER THAN TO SLOW CLEARING A BIT INTO MON
MORNING.
PREV DISCN...
UPPER LEVEL LOW OVER THE NE CONUS FINALLY LOSING ITS GRIP ON OUR
WEATHER...AND WE SHOULD SEE SNOW SHOWERS TAPERING OFF FROM WEST TO
EAST ACROSS THE FORECAST AREA TONIGHT INTO EARLY MONDAY MORNING. ONE
WRENCH IN THE SYSTEM IS ONE FINAL WAVE CURRENTLY OVER CENTRAL
MICHIGAN PER THE WATER VAPOR LOOP. NAM AND ECMWF BRING IT INTO OHIO
AS A CLOSED LOW...THEN OPEN IT UP AS IT CROSSES INTO WEST
VIRGINIA...WHILE THE GFS AND CANADIAN OPEN IT UP SOONER. EITHER
WAY...THERE WILL BE SOME UPPER LEVEL SUPPORT WITH THIS BUT THE LOW
LEVEL MOISTURE IS ALL BUT GONE. MAY SEE SOME ISOLATED SNOW SHOWERS
TONIGHT ACROSS THE LOWLANDS...BUT BETTER CHANCE IN THE NORTHERN
MOUNTAINS WHERE THE BEST...ALBEIT MEAGER...MOISTURE REMAINS. THIS
FINAL WAVE WILL FINALLY GET THE THERMAL TROUGH MOVING. EXPECT
COLDEST 925 AND 850MB TEMPS TONIGHT...WITH SINGLE DIGITS IN THE
MOUNTAINS AND TEENS TO 20S ELSEWHERE. AS THERMAL TROUGH FINALLY
WEAKENS TEMPS WILL REBOUND SOME ON MONDAY AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
ACTIVE WEATHER RETURNS IN THE NEAR TERM PERIOD AS A STRONG LOW
PRESSURE SYSTEM APPROACHES THE AREA FROM THE WEST. STILL SOME
DIFFERENCES BETWEEN THE MODELS DURING THIS TIME...WITH THE GFS AND
NAM FASTER WITH THE SYSTEM...ESPECIALLY WHEN IT COMES TO EXITING TO
THE EAST OF THE CWA...THAN THE ECMWF...AND WITH THE ECMWF CONTINUING
TO KEEP THE LOW FARTHER SOUTH THAN THE AFOREMENTIONED MODELS. AT
THIS POINT...TENDED TO DO A BLEND BETWEEN THE MODELS CONCERNING THE
POPS. AS A RESULT...STILL A BIT OF UNCERTAINTY IN HOW MUCH SNOW WILL
OCCUR IN THE FORECAST...PARTICULARLY ACROSS THE NORTHERN AND EASTERN
ZONES.
AT THIS POINT...WARM FRONTAL BOUNDARY WILL LIFT NORTH ACROSS THE CWA
ON TUESDAY...SPREADING PRECIPITATION INTO THE CWA...NORTH TO SOUTH
AS IT DOES SO. DEPENDING ON THE TIMING OF THE PRECIPITATION...WHICH
MAY INITIALLY BE DELAYED A BIT DUE TO DRIER LOWER LAYERS OF THE
ATMOSPHERE...COULD SEE PRECIPITATION ACROSS SOUTHERN ZONES START OUT
AS SNOW OR A MIX...BEFORE TRANSITIONING OVER TO RAIN AS WARMER AIR
TAKES HOLD. HIGHER TERRAIN...SUCH AS AREAS OVER RANDOLPH/POCAHONTAS
COUNTIES APPEAR AS THOUGH THEY WONT SEE A COMPLETE CHANGEOVER TO
LIQUID...AND MAY EVEN HAVE BRIEF PERIODS OF SLEET TUESDAY LATE
MORNING/AFTERNOON...BEFORE COMPLETELY CHANGING OVER TO SNOW.
PRECIPITATION WILL GRADUALLY CHANGE OVER TO SNOW TUESDAY
EVENING/TUESDAY NIGHT ACROSS THE CWA AS UPPER LOW DEEPENS ACROSS THE
REGION...AND COLDER AIR WORKS ITS WAY INTO THE AREA. AT THIS
POINT...THIS COULD BE A SIGNIFICANT SNOW MAKER...PARTICULARLY ACROSS
THE HIGHER TERRAIN COUNTIES...PARTICULARLY IF THE ECMWF SOLUN HOLDS
TRUE AND IS SLOWER TO EXIT THE CWA...THUS HOLDING ON TO HIGHER
AMOUNTS OF QPF LONGER. AT THIS POINT...WILL NOT ISSUE A WATCH FOR
MOUNTAINOUS COUNTIES PER COORDINATION WITH SURROUNDING OFFICES...AND
SOME MODEL UNCERTAINTY. AT THIS POINT...FIGURING A FEW INCHES
POSSIBLE ACROSS MOST OF THE LOWLAND COUNTIES... EXCEPT FOR MAYBE
EXTREME SOUTHERN/WESTERN ZONES WHERE NOT AS MUCH QPF WILL BE
REALIZED WHEN TEMPERATURES ARE COLD ENOUGH FOR THE GENERATION OF
SNOW. NORTHERN LOWLAND COUNTIES WILL SEE THE MOST SNOW OF THE
LOWLANDS...WHERE 2 TO 4 INCHES MAY BE THE GENERAL RULE WITH SOME
LOCALLY HIGHER AMOUNTS POSSIBLE. ACROSS THE HIGHER TERRAIN
COUNTIES...GENERALLY 6 TO 12 INCHES...WITH HIGHER AMOUNTS POSSIBLE
ACROSS THE PEAKS. OF COURSE THIS IS ALL PRELIMINARY...AND WILL
DEPEND ON A VARIETY OF FACTORS. ONE THING TO NOTE IS IT WILL BE A
HEAVY WET SNOW...AND ANY ACCUMULATIONS COULD RESULT IN PROBLEMS.
WILL HIGHLIGHT SNOWFALL POTENTIAL IN THE HWO FOR NOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES. WILL CONTINUE TO HOLD ONTO LINGERING SNOW SHOWERS
LONGER THAN HPC MEDIUM RANGE GUIDANCE FOR WEDNESDAY NIGHT INTO
THURSDAY MORNING. HOWEVER...850 TEMPERATURES IN THE THERMAL TROF ARE
ONLY MINUS 6 TO MINUS 8...NOT THE IDEAL CRYSTAL GROWTH
TEMPERATURES. SO DESPITE CLOUDS AND HIGHER POPS... NOT THINKING
MUCH IN WAY OF ACCUMULATION OVERNIGHT...WITH AN INCH OR TWO
WEDNESDAY NIGHT OVER THE WV MOUNTAIN COUNTIES.
THE MARCH ENVIRONMENT FINALLY SETTLES DOWN FOR THURSDAY INTO
SATURDAY. A WEAK FEATURE MAY SAG SOUTH FROM THE NORTH...BY SATURDAY
NIGHT...BUT MOISTURE IS LIMITED. WILL LEAVE SOME 20/30 POPS ACROSS
THE NORTH.
DEEPER MOISTURE MAY FINALLY ARRIVE TOWARD SUNDAY NIGHT...AS THIS
PERIOD ENDS.
HELD DOWN MAXIMUM TEMPERATURES A BIT FOR THURSDAY INTO FRIDAY DUE
TO THE MELTING SNOW...BUT THEN FLIRTING WITH 60 BY SATURDAY FOR MUCH
OF SOUTHERN LOWLANDS.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS EXPECTED OVERNIGHT OVER MOST SITES. LOW CHANCE OF
LIGHT SNOW SHOWERS OR FLURRIES STILL POSSIBLE ACROSS EASTERN HALF
OF THE CWA...INCLUDING CRW...CKB...EKN AND BKW UNTIL THE MID DECK
VANISHES FOLLOWED BY MOSTLY CLEAR SKIES EARLY MONDAY. RELAXED
PRESSURE GRADIENT THANKS TO A BUILDING HIGH PRESSURE IS
RESPONSIBLE FOR WEAK TO CALM FLOW OVERNIGHT AND CLEARING SPREADING
FROM WEST TO EAST LATE OVERNIGHT...AND REMAINING INTO MONDAY.
HIGH CLOUDS FROM THE NEXT SYSTEM WILL BE MOVING IN FROM THE
SOUTHWEST MON AFTERNOON...UNDER WEAK FLOW. SOUNDING PROFILES SHOW
STRONG SUBSIDENCE AND VERY DRY AIRMASS AT THE MID LEVELS THROUGH
MONDAY EVENING...UNDER LIGHT TO MODERATE NORTHWEST ALOFT.
MODELS SHOW WARM AIR ADVECTION FROM THE SOUTHWEST AT H850 AHEAD OF
THE NEXT LOW PRESSURE SYSTEM MONDAY NIGHT. AN ASSOCIATED WARM
FRONT WILL BRING PERIODS OF RAIN SPREADING FROM SOUTHWEST TO
NORTHEAST ON TUESDAY FOR MAINLY MVFR CONDITIONS. DEPENDING OF SFC
TEMPERATURES...THERE COULD BE A SHORT PERIOD OF FREEZING RAIN
EARLY TUESDAY WITH THE ONSET OF PCPN. DIFFERENCES IN MODELS
TIMINGS PROVIDE LOW CONFIDENCE FOR FREEZING RAIN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE...HIGH 06Z TAFS. MEDIUM BEYOND 09Z TUESDAY.
ALTERNATE SCENARIOS: TIMING AND PCPN TYPE EARLY TUESDAY MAY VARY
DEPENDING ON THE ONSET OF PCPN AND SFC TEMPERATURES.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 03/04/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L L L H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY L L L L L L L L H H H H
AFTER 06Z TUESDAY...
IFR VISIBILITIES AND CEILINGS POSSIBLE IN RAIN/SNOW TUESDAY INTO
THURSDAY...LINGERING THE LONGEST IN THE WV MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/TRM/MZ
NEAR TERM...ARJ/TRM/MZ
SHORT TERM...ARJ
LONG TERM...KTB
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1109 PM CST SUN MAR 3 2013
.DISCUSSION.../ISSUED AT 651 PM CST/
LIGHT PRECIPITATION OR DRIZZLE HAS DEVELOPED ALONG THE ISENTROPIC
LIFT ACROSS THE NORTHEASTERN HALF OF THE FORECAST AREA THIS EVENING.
TEMPERATURES REMAIN RELATIVELY MILD WITH THE VAST MAJORITY OF OBS
STILL AT OR ABOVE FREEZING. MODELS HAVING QUITE A BIT OF DIFFICULTY
WITH THIS SYSTEM ESPECIALLY AT THE NEAR SURFACE. MUCH OF THE AREA
REMAINS QUITE DRY AT THE LOWER LEVELS WHICH IS NOT WELL HANDLED BY
ANY MODEL EXCEPT PERHAPS THE RAP. WITH THE LACK OF LOW LEVEL
MOISTURE AND THE MILDER SURFACE TEMPERATURES...PRECIPITATION HAS
BEEN VERY LIGHT OR DRIZZLY FOR THE MOST PART. THE HRRR AND RAP
SUGGEST THAT THE ISENTROPIC BAND WILL LIKELY LIFT NORTHEAST INTO THE
EARLY MORNING HOURS...KEEPING THE MORE ORGANIZED PRECIPITATION...AND
SNOWFALL POTENTIAL MAINLY ALONG AND EAST OF A BROOKINGS TO SPENCER
LINE OVERNIGHT. ELSEWHERE...VERY LIGHT RAIN...FREEZING RAIN OR
DRIZZLE IS EXPECTED INTO THE EARLY MORNING HOURS. IF WE CANNOT GET
MORE SIGNIFICANT LOW LEVEL MOISTURE/CLOUDS TO DEVELOP
OVERNIGHT...THE VAST MAJORITY OF THE CWA WILL SEE NO SNOW
DEVELOPMENT.
MADE SOME CHANGES MAINLY TO THE POPS AND PRECIPITATION TYPES. HAVE
DROPPED OFF THE POTENTIAL FOR MEASURABLE PRECIPITATION TO CHANCES OR
SLIGHT CHANGES AFTER MIDNIGHT FOR ALL BUT OUR FAR NORTHEASTERN
COUNTIES...WHICH IS CLOSER IN LINE WITH THE HRRR...RAP AND NAM.
PRECIPITATION TYPES WERE ADJUSTED TO KEEP IN LINE WITH THE WARMER
SURFACE AND LOW LEVEL TEMPERATURES. FOR AREAS OUTSIDE OF THE MORE
ORGANIZED ISENTROPIC LIFT ZONE...NEAR SOUTHWEST MINNESOTA...HAVE
LOWERED QPF...ICE ACCUMULATIONS AND SNOW AMOUNTS WITH MORE DRIZZLY
CONDITIONS BEING REPORTED. ALSO WARMED LOWS A BIT WITH MID AND HIGH
CLOUDS STICKING AROUND TONIGHT AND THE SOMEWHAT BREEZY SOUTHEAST
WINDS HOLDING ON THROUGH THE BULK OF THE NIGHT.
THE WINTER WEATHER ADVISORY REMAINS AS IS...BUT WILL BE REVISITING
THINGS LATER THIS EVENING. MAY POTENTIALLY NEED TO DROP SOME OF THE
WESTERN COUNTIES IF WE DO NOT SEE PRECIPITATION RATES OR LOW LEVEL
MOISTURE INCREASE THROUGH THE NEXT FEW HOURS.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MODELS AGAIN ARE STRUGGLING MIGHTILY IN DEPICTION OF THE NEAR
SURFACE LAYER...EXHIBITING A VERY STRONG COLD AND HIGH RELATIVE
HUMIDITY BIAS. RAP HAS THE BEST HANDLE ON THIS...AND WOULD SUGGEST
LITTLE PRECIPITATION FOR TAF SITES BEYOND THE IMMEDIATE TERM...AND
THIS TYPE WOULD LIKELY REMAIN LIQUID WITH TEMPS ALOFT FOR TAF
SITES...WITH WET BULB PROCESS TO SNOW IN PRECIPITATION BAND LIFTING
NORTHEAST. AS TEMPERATURES DRY OUT ALOFT TONIGHT BEHIND THE MAIN
BAND...INDICATIONS ARE FOR SOME DEVELOPMENT OF IFR OR LIFR CEILINGS
ALONG WITH DRIZZLE/FREEZING DRIZZLE BY LATER TONIGHT AND INTO MONDAY
MORNING. BRIEF PERIOD WITH SOME MID LEVEL CLOUDINESS AS DIV Q
INCREASES LATER MORNING OR MIDDAY COULD YIELD ICE PROCESS
INTRODUCTION AND THREAT FOR A BRIEF PERIOD OF LIGHT SNOWFALL WITH
MVFR OR IFR VISIBILITY. BETTER THREAT FOR SNOWFALL FOR TAF SITES
LOOKS TO EXIST JUST BEYOND CURRENT FORECAST. WINDS WILL INCREASE
BEHIND THE SYSTEM THROUGH THE JAMES AND WESTERN MISSOURI RIVER
CORRIDOR BY VERY LATE AFTERNOON...EXPANDING EASTWARD IN THE EVENING
BEHIND THE INVERTED TROUGH...WHERE SURFACE WIND GUSTS OF 30 TO 40 KNOTS
LIKELY DURING THE LATER EVENING. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 302 PM CST/
ISENTROPIC LIFT ON THE 290 AND 295K SURFACES INCREASING RESULTING IN
SOME LIGHT RAIN ALONG A BAND FROM KHON-KFSD. AS ISENTROPIC LIFT
CONTINUES TO INCREASE...EXPECT BAND TO BECOME MORE ESTABLISHED INTO
THE EVENING HOURS. WARM YET DRY LAYER ALOFT NEAR 850 MB. AS
PRECIPITATION INTENSITY INCREASES...EXPECT LAYER TO EVAPORATIVELY
COOL LEADING TO THE POTENTIAL OF SNOW...HOWEVER...UPPER LEVELS BEGIN
TO DRY OUT FROM THE SOUTHWEST TO THE NORTHEAST MAKING IT DIFFICULT
TO GET ICE INTO THE COLUMN. FOR THIS EVENING...POTENTIAL FOR SOME
LIGHT RAIN/FREEZING RAIN ACROSS MUCH OF THE CWA. HAVE ISSUED WINTER
WEATHER ADVISORY FOR AREAS WHERE THERE IS A HIGHER CONFIDENCE FOR
LIGHT ICING POTENTIAL. WESTERN EDGE OF THE ADVISORY WAS DIFFICULT TO
DETERMINE...AND MAY NEED TO BE EXPANDED IF ICING BECOMES MORE
WIDESPREAD. ACROSS NORTHEAST CORNER OF FORECAST AREA...MAY SEE RAIN
CHANGE OVER TO SNOW THROUGH THE EVENING HOURS WITH A FEW INCHES OF
ACCUMULATION BEFORE THE ISENTROPIC LIFT DIES AWAY FROM WEST TO EAST
FROM 06-12Z MONDAY. MODELS INDICATE FAIR AMOUNT OF LOW LEVEL
SATURATION...AND MAY BE ABLE TO GET FREEZING DRIZZLE/DRIZZLE THROUGH
THE MORNING HOURS.
MAIN UPPER LEVEL WAVE APPROACHES FROM THE WEST NORTHWEST TOMORROW
AFTERNOON. WITH THE APPROACHING MAIN UPPER LEVEL WAVE...LIFT ONCE
AGAIN INCREASES ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST
AREA. FAIRLY SHARP BACK EDGE SHOULD DEVELOP BETWEEN AREAS THAT ARE
ABLE TO SATURATE ALOFT AND THOSE THAT DO NOT. EXPECT BAND OF
PRECIPITATION TO GRADUALLY SHIFT EAST THROUGH THE EVENING
HOURS...WITH WINDS INCREASING BEHIND THE COLD FRONT.
MONDAY NIGHT WILL SEE THE SYSTEM WRAP UP AND DROP THROUGH SOUTHWEST
MINNESOTA. WILL KEEP SOME FAIRLY HIGH POPS IN FOR THE NIGHT OVER THE
EASTERN THIRD OF THE CWA. BEST SNOWFALL SHOULD BE NORTH AND EAST OF
A BROOKINGS TO SPENCER IOWA LINE WHERE AN ADDITIONAL 1 TO 3 INCHES
WILL BE POSSIBLE. COLD AIR ALOFT SHOULD ELIMINATE ANY POTENTIAL FOR
MIXED PRECIPITATION AND THINKING ALL SNOW AT THIS POINT. THE OTHER
CONCERN ON MONDAY NIGHT WILL BE THE STRONG NORTHWEST WIND THAT
DEVELOPS. THE MODELS ARE IN PRETTY GOOD AGREEMENT SWINGING THROUGH
ABOUT 35 KNOTS TO 40 KNOTS AT 925MB ALONG WITH GOOD COLD AIR
ADVECTION SO WIND ADVISORY CRITERIA WILL LIKELY BE MET...ESPECIALLY
WEST OF INTERSTATE 29...MONDAY NIGHT INTO TUESDAY MORNING. WILL PUT
AN ADVISORY DOWN THE MISSOURI RIVER VALLEY CORRIDOR.
THE SNOW SHOULD BE WINDING DOWN TUESDAY MORNING WITH THE STRONG
NORTHWEST WINDS DEVELOPING ACROSS THE AREA. MAY BE SOME AREAS OF
BLOWING SNOW IN LOCATIONS THAT RECEIVE ENOUGH SNOWFALL...MAINLY
SOUTHWEST MINNESOTA. WITH SOME SNOW ON THE GROUND AND WINDY
CONDITIONS WILL WILL BE PRETTY COLD WITH HIGHS MAINLY IN THE LOWER
TO MIDDLE 20S...CLOSER TO 30 ALONG THE MISSOURI RIVER VALLEY WHERE
LITTLE TO NO SNOW IS EXPECTED.
TUESDAY NIGHT INTO WEDNESDAY HIGH PRESSURE WILL BUILD SOUTH INTO THE
AREA THEN SHIFT EAST WITH BREEZY CONDITIONS LIKELY WEDNESDAY
AFTERNOON IN CENTRAL SOUTH DAKOTA. LOWS IN THE MORNING WILL DROP
CLOSE TO ZERO ALONG THE HIGHWAY 14 CORRIDOR INTO SOUTHWEST MINNESOTA
WHILE CENTRAL SOUTH DAKOTA WILL BOTTOM OUT IN THE TEENS. HIGHS ON
WEDNESDAY WILL MODERATE BUT STILL 20 TO 25 IN SOUTHWEST MINNESOTA
AND AROUND 40 IN SOUTH CENTRAL SOUTH DAKOTA.
IN THE LATTER PERIODS(THU/SUN)...OVERALL FAIRLY MILD THROUGH THE
PERIOD AS A TROUGH OF LOW PRESSURE BUILDS OVER THE WESTERN UNITED
STATES. THIS WILL SPREAD A RIDGE OF HIGH PRESSURE ACROSS THE CENTRAL
UNITED STATES. THE MODELS CONTINUE TO SLOW THE PROGRESSION OF THIS
TROUGH AND HAVE VERY LITTLE CONSISTENCY SO NO REAL CONFIDENCE JUST
YET. REGARDLESS...ABOVE NORMAL TEMPERATURES MOST LOCATIONS THAT DO
NOT RECEIVE MUCH NEW SNOW WITH NORMAL TO A BIT BELOW NORMAL IN AREAS
WITH DEEPER SNOWCOVER. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR SDZ038-039-053>055-061-062-066-067-071.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR SDZ050-
052-057>060-063>065-068>071.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR SDZ040-056.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR MNZ071-072-080-081-089-090-097.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
MONDAY FOR IAZ001-012-013-020>022-031-032.
WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR IAZ031.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST
TUESDAY FOR IAZ002-003-014.
NE...WIND ADVISORY FROM 10 PM MONDAY TO NOON CST TUESDAY FOR NEZ013-
014.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
359 AM CST MON MAR 4 2013
.SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH
ALL MODELS INDICATE BEGINNING OF SNOW WITH INITIAL WAA
BAND...CURRENTLY PRODUCING 1 TO 2 MILE SNOW IN A BAND FROM SW MN
INTO CENTRAL IOWA...WILL BE DELAYED AND LIGHTER THAN EXPECTED AS IT
RUNS INTO DRY AIR BELOW 5K FT ON CROSS SECTIONS AND 500 MB RIDGE
AMPLIFYING OVER REGION IN RESPONSE TO THE DEEPENING TROUGH AS IT
DROPS INTO THE NRN PLAINS. HRRR IS ESPECIALLY MEAGER...WIPING OUT
THIS INITIAL BAND BEFORE IT GETS TO CWA. RAP AND WRF-CORE MODELS
ALSO WEAKEN THIS INITIAL BAND.
ISENTROPIC FORECASTS INDICATE IT WILL TAKE A BIT LONGER TO SATURATE
THE LOWER LAYERS...WITH ALL MODELS/SAVE THE GFS/ HOLDING PCPN TO THE
WEST OF MADISON THRU 00Z TUE. LOOKING FOR UNDER 1/2 INCH IN THE FAR
WEST THIS MORNING...WITH 1/2 INCH OR LESS FROM MADISON AND WEST BY
00Z TUE. WE DO LOSE MOISTURE IN DENDRITE GROWTH ZONE ON THE GFS
BUFKIT SOUNDINGS IN THE LULL BETWEEN THE INITIAL WEAKENING WAA BAND
AND THE STEADIER SNOW WITH THE SYSTEM DYNAMICS THAT MOVES IN AFTER
00Z TUESDAY...BUT WITH WARMEST TEMP IN COLUMN AT -3C AND WET BULB
BELOW 0C...TOP-DOWN SUGGESTS LIGHT SNOW OR MAYBE SNOW PELLETS VERSUS
FREEZING DRIZZLE.
SNOW WILL INCREASE IN COVERAGE AND INTENSITY AS STRONGER FORCING
MOVES INTO THE REGION AFTER 00Z. WILL TRACK THE INCREASING SNOW FROM
SW TO NE WITH ISENTROPIC LIFT AND STRONGER LAYER Q-VECTOR
CONVERGENCE. THIS KEEPS THE FAR NE OUT OF THE BETTER SNOW UNTIL 12Z
TUE OR LATER.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM
THE CLOSED UPPER LOW OVER THE DAKOTAS WILL DIG DOWN INTO IOWA AND
ABSORB A SOUTHERN STREAM SHORTWAVE AROUND 12Z-18Z TUE. THE SURFACE
LOW OVER SOUTHERN IL WILL DEEPEN AND AN INVERTED TROUGH WILL EXTEND
NORTHWEST ACROSS SOUTHERN WI AND EAST CENTRAL MN. THERE WILL BE
ONGOING WARM AIR ADVECTION /WAA/ AT ALL LEVELS OVER SOUTHERN
WI...BUT ESPECIALLY AT 700 MB DURING THIS TIME.
THAT INVERTED TROUGH AXIS WILL TAKE ON A MORE EAST TO WEST
ORIENTATION AS THE UPPER LOW SITS OVER SOUTHERN IL AND TAKES ON A
SLIGHTLY NEGATIVE TILT. 850-700MB WAA WILL CONTINUE OVER SOUTHERN
WI. THE AXIS OF 850-600MB FRONTOGENESIS WILL ALSO SIT SOMEWHERE IN
THE VICINITY OF SOUTHERN WI...DEPENDING ON THE MODEL OF CHOICE. THIS
AXIS IS SHOWN TO PIVOT RIGHT OVER SOUTH CENTRAL WI FROM 15Z-21Z ON
THE 06Z NAM BEFORE SHIFTING SOUTHEAST LATER AS THE SURFACE AND UPPER
LOW CONTINUE ESE. THE AXIS OF HIGHEST DEEP-LAYER Q-VECTOR
CONVERGENCE WILL SIT OVER SOUTHERN WI FOR A LONG TIME. OMEGA VALUES
WILL BE HIGH DURING THIS TIME PERIOD AS WELL.
THE CANADIAN MODELS BOTH CONTINUE A LOW TRACK FURTHER SOUTH THAN
OTHER MODELS...AND THEREFORE HAVE LIGHTER QPF OVER OUR FORECAST AREA
/CWA/. THE 12Z ECMWF HAD RATHER HIGH QPF OVER SOUTH CENTRAL WI...AS
DID THE 00Z NAM. THE GFS HAS BEEN A STEADY COMPROMISE BETWEEN MANY
OF THE MODELS. THE 00Z ECMWF CAME IN WITH LIGHTER QPF IN SOUTH
CENTRAL WI THAN THE 12Z RUN...BUT HAD SIMILAR QPF ELSEWHERE. THE
CONSENSUS OF ALL MODELS SEEMED TO BE A REASONABLE STARTING POINT FOR
QPF AND THEN BLENDED IT WITH THE HPC QPF AMOUNTS.
TOOK A GENERAL AVERAGE OF SNOW RATIOS BASED ON COBB...1000-500MB
THICKNESSES AND MODEL OUTPUT. SNOW RATIOS SHOULD RANGE FROM 16 IN
THE WESTERN CWA TO 10:1 IN THE EAST AT 12Z TUE...THEN RISE TO A
17-12:1 RANGE AT 18Z TUE...THEN END UP AT 15-16:1 FOR THE WHOLE CWA
AT 00Z WED. 6-HR SNOWFALL AMOUNTS SHOULD BE IN THE 3 TO 5 INCH RANGE
IN SOUTH CENTRAL AND PORTIONS OF SOUTHEAST WI FOR THE WHOLE DAY TUE.
STORM TOTAL SNOWFALL AMOUNTS OF 9 TO 12 INCHES EXPECTED SOUTH
CENTRAL FOR A ROUGHLY 24-HOUR PERIOD.
EXPECTING FAIRLY HIGH SNOWFALL RATES DURING THE DAY ON TUE DUE TO
THE STRONG WAA/VORTICITY ADVECTION AND FRONTOGENESIS SITTING OVER
THE AREA. THIS WILL HAVE A HIGH IMPACT ON BOTH THE MORNING AND
AFTERNOON COMMUTES FOR MOST OF THE FORECAST AREA. DECIDED TO ROLL
THE WESTERN CWA INTO A WINTER STORM WARNING AT 06Z TUE AND THE
EASTERN CWA AT 12Z TUE. WE ARE KEEPING FOND DU LAC AND SHEBOYGAN
COUNTIES IN A WATCH FOR NOW SINCE SNOW AMOUNTS DO NOT LOOK HIGH
ENOUGH AT THIS TIME TO JUSTIFY A WARNING. LATER SHIFTS WILL NEED TO
ASSESS IF THIS AREA NEEDS A WARNING OR JUST AN ADVISORY.
MODELS SUGGEST THAT THE LOW LEVEL CONVERGENCE AND LAKE ENHANCEMENT
SHOULD ONLY INCREASE QPF AMOUNTS BY A FEW HUNDREDTHS.
.LONG TERM...
WEDNESDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM
HIGH PRESSURE WILL MOVE ACROSS THE UPPER MIDWEST ON WED INTO THU.
WARM ADVECTION IN SOUTHERN WI AHEAD OF THE NEXT UPPER TROUGH WILL
LEAD TO TEMPS RISING INTO THE UPPER 30S AND LOWER 40S BY THE END OF
NEXT WEEK. THERE COULD BE SOME LIGHT PRECIP IN THE FORM OF EITHER
RAIN OR SNOW OR DRIZZLE FRI NIGHT AND SATURDAY WITH THE WARM AIR
ADVECTION PATTERN AND A SHORTWAVE. IT WILL DEPEND ON HOW QUICKLY A
CLOSED UPPER LOW OVER THE SOUTHWEST EJECTS INTO THE PLAINS FOR
WHETHER THE LATTER HALF OF THE WEEKEND WILL BE IN THE 40S OR THE 20S
FOR HIGH TEMPS.
&&
.AVIATION/12Z TAFS/...
WILL GRADUALLY INCREASE CLOUD COVERAGE AND SLOWLY LOWER HEIGHTS FROM
WEST TO EAST TODAY. WILL KEEP AN EYE ON RADAR TRENDS...BUT PLAN IS
TO KEEP PREVIOUS FORECAST TREND OF NO SNOW AT KMSN UNTIL CLOSER
TO/JUST AFTER 00Z TUE...AND EASTERN TAF SITES UNTIL 06Z OR LATER.
SHOULD KEEP VFR CIGS VSBYS UNTIL STEADIER SNOW BEGINS...THEN GO TO
MVFR. IFR VSBYS AND 1 IN/HOUR ACCUMULATION RATES SHOULD HOLD OFF
UNTIL AFTER 12Z TUESDAY. EAST WINDS WILL BE SLOWLY INCREASING...WITH
OCCASIONAL 15 TO 20 KNOT GUSTS MIXING DOWN AFTER 06Z.
&&
.MARINE...CURRENT WIND AND WAVE HEIGHT FORECASTS INDICATE A SMALL
CRAFT ADVISORY WILL LIKELY BE NEEDED FROM TUESDAY THROUGH WEDNESDAY
MORNING EVERYWHERE...AND POSSIBLY THROUGH WEDNESDAY AFTERNOON IN THE
SOUTH. START TIME IS A BIT IN QUESTION...AND WITH SURROUNDING
OFFICES HOLDING OFF AT THIS TIME...WILL NOT ISSUE ADVISORY...BUT
WOULD NOT BE SURPRISED TO SEE ONE HOISTED LATER THIS MORNING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING FROM 6 AM TUESDAY TO MIDNIGHT CST TUESDAY
NIGHT FOR WIZ058>060-064>066-070>072.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR WIZ046-047-056-057-062-063-067>069.
WINTER STORM WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING
FOR WIZ051-052.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CST MON MAR 4 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
343 AM CST MON MAR 4 2013
FORECAST FOCUS REMAINS ON WINTER STORM IMPACTING THE REGION TODAY
THROUGH TUESDAY.
LATEST WATER VAPOR IMAGERY AND RAP 500 MB ANALYSIS SHOWED A POTENT
LOW CENTERED OVER WESTERN MONTANA. A LEADING SHORTWAVE WAS MOVING
EAST ACROSS WESTERN MINNESOTA/IOWA. A BAND OF LIGHT SNOW EXTENDED
FROM WEST CENTRAL MINNESOTA...SOUTHEAST THROUGH SOUTHEAST
MINNESOTA INTO EASTERN IOWA. VISIBILITIES WITHIN THIS BAND HAD
FALLEN INTO THE 1 TO 2 MILE RANGE.
THE ONGOING BAND OF SNOW WILL CONTINUE MOVING EAST/NORTHEAST THIS
MORNING ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...APPROACHING
THE MISSISSIPPI RIVER DURING THE MID TO LATE MORNING HOURS.
MESOSCALE MODELS SHOW THE BAND REALLY FALLING APART AS IT MOVES
INTO WESTERN WISCONSIN LATE THIS MORNING INTO EARLY THIS AFTERNOON
AND REALLY NOT MAKING IT TO THE INTERSTATE 94 CORRIDOR AS IT
ENCOUNTERS VERY DRY AIR. KEAU FORECAST SOUNDINGS SHOW THE DRY AIR
EXTENDING FROM THE SURFACE THROUGH AROUND 5KFT...SO IT WILL TAKE
SOME TIME FOR SATURATION TO OCCUR. SNOW ACCUMULATIONS TODAY WILL
BE ON THE LIGHT SIDE RANGING FROM 1 TO POSSIBLY 3 INCHES OVER
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA TO AROUND AN INCH OVER FAR
WESTERN WISCONSIN. FRONTOGENESIS INCREASES...IN THE 850-700 MB
LAYER...THIS AFTERNOON RIGHT ALONG THE MISSISSIPPI RIVER. THIS
COULD KEEP LIGHT SNOWFALL INTO THE EARLY AFTERNOON HOURS BEFORE IT
WANES. GFS FORECAST SOUNDINGS THIS AFTERNOON OVER SOUTHEAST
MINNESOTA....NORTHEAST IOWA...AND FAR SOUTHWEST WISCONSIN SHOW A
LOSS OF ICE ALOFT WHICH COULD LEAD TO SOME FREEZING DRIZZLE. THE
NAM ON THE OTHER HAND KEEPS THE ICE ALOFT ACROSS THESE AREAS.
GIVEN THE CONSISTENT SIGNAL FOR A LOSS OF ICE IN THE GFS WILL
INTRODUCE A SLIGHT CHANCE OF FREEZING DRIZZLE ACROSS THESE AREAS
THIS AFTERNOON INTO EARLY THIS EVENING.
THE LOW WILL DIVE SOUTHEAST TONIGHT INTO THE UPPER MISSISSIPPI RIVER
VALLEY. VERY IMPRESSIVE LARGE SCALE FORCING ASSOCIATED WITH THE LOW
WITH DEEP QG FORCING NOTED PARTICULARLY IN THE 700-500 MB LAYER. A
BROAD AREA OF ISENTROPIC LIFT...MAINLY FOCUSED ON THE 280-310 K
SURFACES...WILL DEVELOP ACROSS THE FORECAST AREA THIS EVENING AND
CONTINUE THROUGH THE OVERNIGHT HOURS. SREF PROBABILITIES FOR SNOWFALL
RATES OF AN INCH PER HOUR DEVELOP ACROSS MOST OF THE FORECAST AREA
THIS EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS INTO TUESDAY
MORNING. OVERALL FORECAST MODELS ARE IN CLOSE AGREEMENT THIS CYCLE
PLACING A BROAD SWATH OF HEAVY SNOW ACROSS MUCH OF THE AREA WITH
ACCUMULATIONS RANGING FROM 8 TO 13 INCHES. THE HIGHEST
ACCUMULATIONS WILL BE ALONG THE MISSISSIPPI RIVER...AND INCLUDING
ALL OF SOUTHWEST WISCONSIN. DECIDED TO ISSUE A WINTER STORM
WARNING FOR CENTRAL AND NORTH CENTRAL WISCONSIN STARTING AT 6 PM
THIS EVENING AND CONTINUING THROUGH 6 PM TUESDAY. WILL CONTINUE
THE WINTER STORM WARNING FOR THE REST OF THE FORECAST AREA...BUT
PLAN ON THE BULK OF THE ACCUMULATING SNOW TO OCCUR TONIGHT THROUGH
TUESDAY MORNING. GIVEN THE FORCING OVERNIGHT INTO TUESDAY
MORNING...THE SNOW WILL BE HEAVY AT TIMES ESPECIALLY FOR THE
TUESDAY MORNING COMMUTE. THE SNOW IS EXPECTED TO TAPER OFF FROM
NORTHWEST TO SOUTHEAST LATE TUESDAY AFTERNOON AND FINALLY EXIT THE
AREA TUESDAY NIGHT. THE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA
TUESDAY AFTERNOON INTO TUESDAY EVENING WITH NORTH WINDS INCREASING
TO 10 TO 17 MPH WITH GUSTS AROUND 25 MPH POSSIBLE. WILL HAVE TO
KEEP A CLOSE WATCH ON THE POTENTIAL FOR BLOWING SNOW. ALSO...LOW
TEMPERATURES TUESDAY NIGHT COULD BE CHALLENGING WITH THE FRESH
SNOW PACK AND DECREASING CLOUDS. IF CLOUDS CLEAR EARLIER THAN
FORECAST LOWS COULD BE SEVERAL DEGREES COLDER.
HIGH PRESSURE IS EXPECTED TO BUILD INTO THE REGION ON WEDNESDAY AS
RIDGING INTENSIFIES OVER THE CENTRAL CONUS. PLAN ON PARTLY TO MOSTLY
SUNNY SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WITH HIGHS RANGING
FROM THE LOWER 30S OVER NORTHERN WISCONSIN TO THE MID 20S ACROSS
SOUTHEAST MINNESOTA.
.LONG TERM...THURSDAY THROUGH SUNDAY
343 AM CST MON MAR 4 2013
04.00 MEDIUM RANGE MODELS ARE IN AGREEMENT THURSDAY INTO FRIDAY
SHOWING RIDGING OVER THE UPPER MIDWEST. A SHORTWAVE LOOKS TO PASS
JUST NORTH OF THE AREA ACROSS NORTHERN MINNESOTA THROUGH SOUTHERN
ONTARIO. THIS FEATURE WILL BRING A SLIGHT CHANCE OF SNOW TO FAR
NORTHERN WISCONSIN AS IT MOVES THROUGH THURSDAY NIGHT. MODEL
SOLUTIONS START TO DIVERGE LATE FRIDAY THROUGH THE WEEKEND WITH THE
HANDLING OF AN UPPER LOW OVER THE DESERT SOUTHWEST. THE ECMWF TAKES
THE LOW INTO THE PLAINS ON SATURDAY...LIFTING INTO THE UPPER
MISSISSIPPI RIVER VALLEY SUNDAY INTO MONDAY. THE GFS KEEPS A CUTOFF
LOW OVER THE SOUTHWEST AND BRINGS AN OPEN WAVE ACROSS THE REGION.
GIVEN THE MODEL DIFFERENCES WILL LEAN TOWARD A MODEL CONSENSUS BLEND
THROUGH THE WEEKEND WITH PRECIPITATION CHANCES FRIDAY NIGHT THROUGH
SUNDAY. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW FORECAST
MODEL RUNS SINCE THE SOUTHWEST LOW HAS THE POTENTIAL TO BRING RAIN
AND MUCH WARMER TEMPERATURES TO THE AREA. THE ECMWF WARMS
TEMPERATURES INTO THE 50S ON MONDAY AND BRINGS NEARLY 1/2 INCH OF
RAIN INTO THE AREA. THROUGH THE WEEKEND...PLAN ON TEMPERATURES NEAR
TO SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE UPPER 30S TO AROUND 40.
&&
.AVIATION...
1130 PM CST SUN MAR 3 2013
VERY CHALLENGING FORECAST FOR THE NEXT 24-36 HOURS.
SHORTWAVE TROUGH SPAWNING AN AREA OF SNOW/MIXED PCPN OVER SOUTHWEST
MN/WESTERN IA. MUCH DRIER AIR CLOSER TO THE TAF SITES THOUGH...PER
00Z DVN/MPX SOUNDINGS...AND THIS WILL NEED TO COOL AND
SATURATION...WHICH MAKES -SN THE PCPN TYPE LOCALLY. HOWEVER...THERE
IS A LOT OF SATURATION THAT NEEDS TO BE ACCOMPLISHED...AND THE MESO
MODELS ALONG WITH THE LATEST NAM/GFS RUNS CONTINUE TO DEPICT A
DIMINISHING TREND IN INTENSITY AND AREAL COVERAGE OF THE PCPN BAND.
WILL DELAY ONSET OF VSBY RESTRICTING -SN BASED ON THIS. AMOUNTS
WON/T BE MUCH TODAY AS A RESULT. ABOUT 1 TO 2 AT KRST...PERHAPS UP
TO AN INCH AT KLSE. THE CAVEAT HERE IS SOME OF THE MESO MODELS
SUGGEST CONVECTIVE ELEMENTS POST THIS SNOW BAND. IF THESE WOULD MOVE
IN...AN INCH IN AN HOUR WOULD BE POSSIBLE...ALONG WITH 1SM VSBYS.
CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN TAFS AT THIS TIME. CIGS
SHOULD CONTINUE TO LOWER THROUGH THE DAY THOUGH.
A STRONGER UPPER LEVEL SHORTWAVE WILL MOVE IN FOR MONDAY
NIGHT...IMPACTING THE REGION THROUGH TUESDAY. THIS SYSTEM WILL PACK
MORE OF A PUNCH...WITH HIGH SNOW RATES/SNOW FALL AMOUNTS. LIFR/IFR
CIGS ARE EXPECTED ON TUE...WITH VSBYS 1/2 TO 1 1/2SM IN SN. WINDS
WILL BLOW AND DRIFT MUCH OF THE SNOW...FURTHER LOWERING VSBYS AND
IMPACTING RUNWAY CLEARING OPERATIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 PM CST SUN MAR 3 2013
WI...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
WIZ032-033-041-053>055-061.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY
AFTERNOON FOR WIZ017-029-034-042>044.
MN...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR MNZ079-086-087-094-095.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
MNZ088-096.
IA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR IAZ008-009-018-019.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
IAZ010-011-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
411 AM MST MON MAR 4 2013
.SHORT TERM...DIFFICULT FORECAST TODAY. CURRENT SURFACE ANALYSIS
SHOWS COLD FRONT HAS PUSHED INTO THE DENVER METRO AREA. THIS FRONT
IS QUITE SHALLOW...BUT WILL PROVIDE COOLING AND ENOUGH UPSLOPE FOR
POTENTIAL STRATUS AND A FEW LIGHT SNOW SHOWERS THIS MORNING.
HOWEVER...MID/UPPER LEVELS WERE BEGINNING TO SHOW SOME SIGNS OF
DRYING FROM THE NORTH...AS RADAR SHOWS SNOW IN THE NORTHERN FRONT
RANGE MOUNTAINS DECREASING. MEANWHILE...SUMMIT COUNTY CAMS AND
RADAR SHOWS GOOD SNOW CONTINUING IN THE I-70 MOUNTAIN CORRIDOR
WITH POOR TRAVEL CONDITIONS. GJT RADAR SHOWS ANOTHER BATCH OF
HIGHER RETURNS TO PUSH INTO THAT EARLY EARLY THIS MORNING BEFORE A
DECREASE OCCURS LATER. WILL LET THE MOUNTAIN ADVISORIES CONTINUE
TIL NOON. POSSIBLE EXTENSION OF ADVISORIES MAY BE REQUIRED WITH
NEXT SHORT WAVE/SPEED MAX THIS AFTERNOON.
THIS NEXT UPPER LEVEL WAVE CREATES MOST OF THE CHALLENGE WITH
TODAYS FORECAST. CURRENT UPPER LEVEL ANALYSIS SHOWS THIS FEATURE
DROPPING ACROSS IDAHO WITH ENHANCED CLOUDINESS ON THE POLEWARD
SIDE. THIS FEATURE WILL REACH NORTHERN COLORADO THIS AFTERNOON. AT
THE SAME TIME...SOME DEEPENING OF THE UPSLOPE FLOW WILL LIKELY
OCCUR WITH ANOTHER ANTICYCLONIC SURGE FROM THE NORTH. AT THIS
TIME...THIS SHOT OF UPSLOPE APPEARS TO BE SHORT LIVED...BUT ENOUGH
TO PRODUCE SNOW SHOWERS ALONG THE FRONT RANGE AND SOUTH/SOUTHEAST
ACROSS THE PALMER DIVIDE TO LINCOLN COUNTY. THIS COULD PLAY HAVOC
WITH THE AFTERNOON RUSH WITH A QUICK INCH OF SNOW POSSIBLE...BUT
ROADS TEMPS ARE EXPECTED TO BE WARM ENOUGH TO MELT MOST SNOW THAT
FALLS...IF IT SNOWS. WE DO THINK WITH THE QUICK SHOT OF
UPSLOPE...FAVORABLE SURFACE Q-G VERTICAL MOTION...AND APPROACH OF
UPPER LEVEL SPEED MAX...ENOUGH FACTORS WARRANT AN INCREASE IN POPS
TO LIKELY FOR THE DENVER METRO AND POINTS SOUTH AND EAST THIS
AFTERNOON. WITH STRONG GUSTY NORTHERLY WINDS...WILL ADD AREAS OF
BLOWING SNOW TO THE FORECAST AS WELL EAST/SOUTHEAST OF DENVER. AN
ADVISORY MAY BE NEEDED FOR THOSE LOCATIONS DUE TO COMBINATION OF
GUSTY WINDS AND HIGHER PROBABILITY OF SNOW...WILL CONTINUE TO
MONITOR.
THINGS DRY OUT RATHER QUICKLY FROM NORTH TO SOUTH THIS EVENING
WITH CLEARING SKIES OVERNIGHT. TEMPERATURES WILL BE COLD
ESPECIALLY WHERE WINDS DECREASE SUFFICIENTLY.
.LONG TERM...AN UPPER LEVEL RIDGE WILL BE OVER THE AREA ON TUE
WITH DRY WLY FLOW ALOFT. TEMPS WILL MODERATE SOME WITH READINGS
IN THE MID TO UPPER 40S ACROSS NERN CO. FOR WED THE FLOW ALOFT
WILL BECOME MORE SWLY AS AN UPPER LEVEL TROUGH DEVELOPS OVER THE
WRN US. SOME MID AND HIGH LEVEL MOISTURE WILL MOVE ACROSS BUT
OUTSIDE OF SOME CLOUDS IT SHOULD REMAIN DRY. 850-700 TEMPS WOULD
SUPPORT HIGHS IN THE 50S TO NR 60 OVER NERN CO.
FOR THU THE UPPER LEVEL TROUGH WILL INTENSIFY OVER THE WRN US WITH
SWLY FLOW CONTINUING. ONCE AGAIN SOME MID AND HIGH LEVEL MOISTURE
WILL BE EMBEDDED IN THE FLOW HOWEVER OUTSIDE OF A SLIGHT CHC OF
-SHSN WEST OF THE DIVIDE MAINLY IN ZN 31 IT LOOKS DRY. HIGHS WILL
REMAIN MILD ONCE AGAIN OVER NERN CO WITH READINGS IN THE MID 50S
TO LOWER 60S. BY FRI AN UPPER LEVEL STORM SYSTEM WILL DEVELOP OVER
SRN CALIFORNIA WITH SSW FLOW ALOFT. BOTH THE GFS AND ECMWF SHOW AN
INCREASE IN MOISTURE HOWEVER WITH SSW FLOW AT 700 MB BEST SHOT OF
SNOW WILL STAY WEST OF THE DIVIDE. EAST OF THE MTNS A CDFNT WILL
TRY TO BACKDOOR INTO NERN CO DURING THE DAY AS SFC LOW PRES DVLPS
OVER SRN CO. AT THIS TIME WILL DROP HIGHS BACK INTO THE 40S ACROSS
NERN CO. CROSS-SECTIONS REALLY DO NOT SHOW THAT MUCH MOISTURE IN
THE LOWER LEVELS THRU FRI AFTN SO WILL ONLY MENTION A SLIGHT CHC
OF SHOWERS IN AND NR THE FOOTHILLS.
BY THE WEEKEND THERE ARE MAJOR DIFFERENCES BETWEEN THE GFS AND
ECMWF MODELS WITH REGARDS TO HANDLING OF THE UPPER LEVEL STORM
SYSTEM OVER SRN CALIFORNIA. THE GFS SHOWS A SIGNIFICANT PIECE OF
ENERGY LIFTING ENE OUT OF THE MAIN LOW AND TRACKS IT ACROSS NERN
CO BY SAT NIGHT WHILE THE UPPER LEVEL LOW MOVES INTO SRN ARIZONA.
MEANWHILE THE GFS SHOWS A SECONDARY SURGE OF COLDER AIR MOVING
INTO NERN CO FRI NIGHT INTO SAT WITH INCREASING UPSLOPE FLOW AS
THE PIECE OF ENERGY MOVES ACROSS LEADING TO A GOOD CHANCE OF PCPN FRI
NIGHT THRU SAT AFTN ESPECIALLY EAST OF THE DIVIDE ACROSS THE
PLAINS. FCST THICKNESSES SUGGEST MOST OF THE PCPN WOULD FALL AS
SNOW OVER NERN CO WITH SEVERAL INCHES POSSIBLE. BY SAT NIGHT INTO
SUN THE SECOND PIECE OF ENERGY OVER SRN ARIZONA MOVES EAST ACROSS
SRN NEW MEXICO AS MUCH DRIER AIR SPREADS ACROSS NRN CO. THUS THIS
WOULD LEAD TO LITTLE ADDITIONAL PCPN SAT NIGHT THRU SUN.
MEANWHILE THE ECMWF...GEM AND EVEN SEVERAL OF THE GFS ENSEMBLE
MEMBERS SHOW THE UPPER LEVEL LOW OVER SRN CALIFORNIA REMAINING AS
COMPACT SYSTEM AND MOVING ENE INTO SRN COLORADO/NRN NEW MEXICO BY
SAT NIGHT AND THEN INTENSIFYING OVER ERN CO/WRN KANSAS BY SUN
MORNING. BASED ON THIS SOLUTION THE BEST CHC OF PCPN WOULD BE FM
SAT AFTN INTO SUN ACROSS NRN CO WITH STILL SEVERAL INCHES OF SNOW
POSSIBLE HOWEVER IT WOULD BE DELAYED ROUGHLY 18 HOURS VS WHAT THE
OPERATIONAL GFS IS SHOWING. OVERALL THE ECMWF HAS BEEN VERY
CONSISTENT SHOWING THIS STORM SYSTEM AFFECTING NRN CO FOR THE LAST
4 DAYS WHILE THE GFS HAS HAD A PLETHORA OF DIFFERENT SOLUTIONS. AT
THIS POINT SINCE THE TIMING OF THE SYSTEM IS STILL SOMEWHAT
CERTAIN WILL KEEP POPS IN THE CHC CATEGORY FM FRI NIGHT THRU SUN
UNTIL IT BECOMES MORE CLEAR ON WHEN THE BEST CHC OF PCPN WILL
OCCUR.
&&
.AVIATION...DIFFICULT FORECAST WITH REGARD TO STRATUS THIS MORNING
AND BETTER CHANCE OF SNOW THIS AFTERNOON. WITH SUFFICIENT BUT VERY
SHALLOW UPSLOPE AND CLOSE T/TD SPREADS EARLY THIS MORNING...WE
WOULD EXPECT A STRATUS DECK NEAR 1000-1500 FT AGL TO DEVELOP IN
THE EARLY MORNING HOURS...BUT QUITE A BIT OF UNCERTAINTY AS KCYS
REPORTED A 300 FOOT CEILING EARLIER ONLY TO HAVE IT
DISSIPATE...AND THEN REFORM AGAIN NEAR 1000 FT AGL. BY 16Z-18Z...
COULD SEE SNOW SHOWERS BEGIN TO DEVELOP IN THE AREA BUT BEST
CHANCE PER LATEST HRRR AND RAP SUGGEST 20Z- 23Z FOR MAIN THREAT.
COULD SEE VSBYS BRIEFLY DROP TO ONE HALF MILE IN A HEAVIER SNOW
SHOWER WITH A QUICK INCH OF SNOW. MOST LIKELY SCENARIO IS FOR A
DUSTING TO LESS THAN 1 INCH...BUT A CHANCE OF 1-2 INCH SNOW
BETWEEN 20Z AND 23Z. BY 00Z-02Z ALL SNOW SHOULD BE OUT OF THE AREA
WITH CLEARING SKIES. NORTH/NORTHEAST WINDS TODAY SHOULD GUST TO
BETWEEN 25 AND 30 KTS...WITH STRONGEST WINDS BEFORE 14Z AND THEN
AGAIN AFTER NEXT FRONTAL PUSH 19Z-21Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY FOR COZ031-033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RPK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
551 AM CST MON MAR 4 2013
.DISCUSSION...
ISSUED 315 AM CST MON MAR 4 2013
TIGHT THERMAL GRADIENT MOVING INTO FAR WESTERN ILLINOIS EARLY THIS
MORNING...WITH 850 MB TEMPERATURES RISING ABOUT 6 DEGREES CELSIUS
IN ABOUT A 60 MILE SPAN. ISENTROPIC LIFT ASSOCIATED WITH THIS
GRADIENT HAS PRODUCED SOME LIGHT FREEZING RAIN AND SNOW OVER
IOWA...WITH LIGHT SNOW AND SLEET ACROSS WESTERN ILLINOIS JUST EAST
OF THE MISSISSIPPI RIVER. UPPER LOW DROPPING SOUTHEAST ACROSS
MONTANA IS PART OF THE MAIN SHOW THAT WILL BE AFFECTING OUR
WEATHER THE NEXT COUPLE DAYS...ALONG WITH A SURFACE LOW CURRENTLY
ANALYZED OVER WESTERN OKLAHOMA.
PRIMARY FORECAST CONCERN IN THE SHORT TERM INVOLVES PRECIPITATION
TYPES AND AMOUNTS THROUGH TUESDAY NIGHT. IN THE LONGER TERM...
FOCUS SHIFTS TOWARD A WARMER STORM SYSTEM THAT ARRIVES SOMETIME
NEXT WEEKEND.
SHORT TERM...TODAY THROUGH WEDNESDAY...
STRONGEST LIFT WITH THE CURRENT PRECIPITATION SHOULD LAST THROUGH
ABOUT MID MORNING...AND MOST OF THE MODELS HAVE BEEN WEAKENING
THIS PRECIPITATION WITH TIME. HIGHEST POPS EXPECTED TO BE EARLY
MORNING IN THE NORTHWEST CWA...WITH THE NAM...ECMWF AND RAP MODELS
ALL SUGGESTING MAINLY DRY CONDITIONS THE REMAINDER OF THE DAY.
SURFACE LOW PROGGED TO MOVE INTO WESTERN KENTUCKY AFTER
MIDNIGHT...WITH THE UPPER LOW DROPPING SOUTHEAST INTO CENTRAL
ILLINOIS BY LATE TUESDAY AFTERNOON. PRECIP DEVELOPMENT SHOULD
BEGIN IN EARNEST BY MID TO LATE THIS EVENING AND EXPAND
OVERNIGHT...AS INVERTED SURFACE TROUGH ASSOCIATED WITH THE LOW TO
OUR SOUTH SWINGS THROUGH THE AREA. HAVE SOME CONCERNS WITH PRECIP
TYPES OVERNIGHT AND EARLY TUESDAY...AS NAM AND GFS SOUNDINGS
SHOWING SOME DECENT WARMING IN THE LOWER LAYERS AFTER MIDNIGHT AND
SOME OF THE PRECIP MAY BE RAIN FOR A TIME AS FAR NORTH AS PEORIA.
WITH THE TREND TOWARD SOME WARMER CONDITIONS FOR A TIME... HAVE
HELD OFF ON ANY WINTER HEADLINES AS THE AMOUNT OF SNOW REMAINS IN
FLUX...BUT STILL LOOKS LIKE THE AREAS NORTH OF I-74 ARE MOST LIKELY
TO GET A FEW INCHES OR MORE OF ACCUMULATION THROUGH TUESDAY NIGHT.
MORE OF A TREND TOWARD SNOW IS EXPECTED ON TUESDAY AS THE SURFACE
LOW MOVES UP THE OHIO VALLEY. THE SOUTHEAST CWA IS EXPECTED TO
REMAIN RAIN A GOOD PORTION OF THE TIME...WITH A CHANGEOVER TO SNOW
LATE TUESDAY AFTERNOON. SNOW IS EXPECTED TO LINGER MOST OF THE
EVENING OVER THE ENTIRE AREA AS THE UPPER LOW PASSES...THEN
DIMINISH AFTER MIDNIGHT WITH THE LOW EXITING THE AREA.
LONG TERM...THURSDAY THROUGH SUNDAY...
A MUCH WARMER PATTERN IS STILL ON TAP FOR LATE WEEK...AS AN UPPER
LOW DIGS ALONG THE CALIFORNIA COAST AND PROVIDES A SOUTHWEST FLOW
INTO THE MIDWEST. MAIN FOCUS WILL BE WITH THE EVOLUTION OF THIS
LOW DURING THE WEEKEND...AND HOW THE BRANCHES OF THE JET STREAM
PHASE OVER THE CENTER OF THE COUNTRY. THE GFS MODEL CUTS THE LOW
OFF OVER THE DESERT SOUTHWEST AND PROVIDES MUCH MORE PHASING...
AND THUS A WETTER PATTERN LATER IN THE WEEKEND. MEANWHILE... THE
ECMWF IS MUCH SLOWER WITH LIFTING THE LOW NORTHEAST AND FORMING A
LARGE OCCLUDED SYSTEM OVER THE MID SECTION OF THE NATION...WHICH
WOULD HOLD OFF MUCH OF THE RAIN THREAT UNTIL LATER ON SUNDAY. WILL
GO WITH LOW POPS OF 20-30 PERCENT DURING THE WEEKEND FOR NOW...
HIGHEST IN THE WEST...BUT CONFIDENCE IS LOW DUE TO THE LARGE MODEL
DISCREPANCIES.
GEELHART
&&
.AVIATION...
ISSUED 551 AM CST MON MAR 4 2013
A WINTER STORM WILL APPROACH THE CENTRAL ILLINOIS TERMINALS DURING
THE 12Z TAF VALID TIME. A BAND OF MAINLY LIGHT SNOW WILL CROSS THE
AREA THIS MORNING...CAUSING A BRIEF REDUCTION TO MVFR OR IFR
CONDITIONS. WHILE ADDITIONAL PRECIPITATION IS POSSIBLE DURING THE
PERIOD...THE COVERAGE SHOULD BE QUITE LOW UNTIL VERY LATE TONIGHT.
THEN...A STEADIER SNOW WILL BEGIN TO SPREAD FROM WEST TO EAST
TOWARD DAYBREAK TUESDAY. THE MORE WIDESPREAD SNOW SHOULD BE
ACCOMPANIED BY IFR CONDITIONS.
PREDOMINANTLY SOUTHEAST WINDS ARE EXPECTED THROUGH THE PERIOD
AHEAD OF THE APPROACHING STORM. THE WINDS WILL GUST OVER 20 KTS AT
TIMES DURING THE DAYLIGHT HOURS TODAY.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
658 AM EST MON MAR 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EST MON MAR 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHORTWAVE TROUGH
OVER ERN MONTANA WITH A MID/UPPER LEVEL RIDGE EXTENDING FROM THE
PLAINS INTO THE UPPER GREAT LAKES. AT THE SFC...A RIDGE EXTENDED
FROM NRN MANITOBA INTO WRN UPPER MI. SHALLOW LOW-LVL MOISTURE AIDED
BY CONTRIBUTION OFF LAKE SUPERIOR IN NNE FLOW HAS GENERATED SOME
LAKE CLOUDS FOR AREAS EAST OF MQT. LACK OF RADAR RETURNS EARLY THIS
MORNING SUGGEST LTL MORE THAN FLURRIES ASSOC WITH THESE LAKE CLOUDS.
CLEAR SKIES OVER THE WEST HALF HAS RESULTED IN TEMPS FALLING INTO
THE SINGLE DIGITS BLO ZERO AT MANY LOCATIONS EARLY THIS MORNING.
TODAY...WEAK UPSLOPE NE FLOW INTO N CNTRL UPPER MI MAY GENERATE SOME
FLURRIES DESPITE INVERSION HEIGHTS BELOW 3K FT. WITH LOW CONFIDENCE
IN ANY MEASURABLE LES...HAVE DROPPED MENTION OF SLIGHT CHANCE POPS.
WITH ANTICYCLONIC/DIFLUENT ENE FLOW...ANY FLURRIES THAT FORM SHOULD
END BY MIDDAY. LOOK FOR MAX TEMPS TO REBOUND INTO THE UPPER 20S AND
LOWER 30S...PER FCST SOUNDINGS LOW LEVEL TEMP PROFILE.
TONIGHT...MODELS CONSISTENT IN SHOWING ERN MT SHORTWAVE DIVING WELL
SE OF THE UPPER GREAT LAKES LATER TONIGHT. WITH BEST Q-VECT CONV AND
WAA/ISENTROPIC LIFT STAYING GENERALLY SE OF FCST AREA ALONG TRACK OF
SHORTWAVE AND ASSOC INVERTED SFC TROUGH...MUCH OF CWA SHOULD STAY
DRY THROUGH TONIGHT UNDER INFLUENCE OF SFC HIGH PRESSURE RIDGE. KEPT
ONLY SLIGHT CHC POPS IN FCST OVER FAR WRN LAKE SUPERIOR LATE
TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 501 AM EST MON MAR 4 2013
AT 12Z TUE AN UPPER ANS SFC RIDGE WILL BE OVER THE ERN CWA...BUT
WILL SHIFT E AS AN UPPER TROUGH MOVES IN FROM THE W. THE UPPER
TROUGH WILL MOVE E OF THE CWA BY 00Z THU...BRINGING IN COLDER
INVERSION TOP TEMPS...BETTER SYNOPTIC LIFT AND MORE CYCLONIC
FLOW...WHICH WILL SUPPORT INCREASED LES WITH NE-N LOW LEVEL WINDS
TUE INTO THU. THE BEST COVERAGE AND INTENSITY OF LES IS EXPECTED
TUE/TUE NIGHT...BUT WILL STILL NOT BE ALL THAT HEAVY DUE TO MARGINAL
CONDITIONS AND LOW SNOW TO LIQUID RATIOS. THE SOUTHERN PART OF THE
UPPER TROUGH WILL BE CLOSED OFF AND WILL MOVE WELL S OF THE CWA ON
TUE...WITH SOME SYNOPTIC SNOW POSSIBLY CLIPPING THE IRONWOOD AREA
TUE...BUT ONLY MINOR SNOWFALL AMOUNTS WOULD BE POSSIBLE. WOULD
EXPECT LES TO TAPER OFF AND END WHEN WINDS TURN SLY THU AS A SFC
RIDGE MOVES THROUGH...BUT WARMING TEMPS AND ANTICYCLONIC FLOW WILL
KEEP LES FROM FORMING OFF LAKE MICHIGAN.
EXPECT A COUPLE OF SHORTWAVES TO MOVE NEARBY FRI AND SAT...BUT DO
NOT EXPECT MUCH IN THE WAY OF PRECIP...ESPECIALLY WHEN LOOKING AT
THE MORE CONTINUITOUS ECMWF AND GEM MODELS AS THE GFS DOES PUMP OUT
A GOOD AMOUNT OF PRECIP SAT INTO SUN. PREFERRED THE NON-GFS
SOLUTIONS FOR THIS PART OF THE FORECAST. THEN EXPECT SFC RIDGING TO
MOVE IN ON SUN.
TEMPS WILL GENERALLY BE ON THE RISE...WITH HIGHS AOA FREEZING IN
MOST LOCATIONS FROM THU ON. FOR THE WEEKEND...HIGH TEMPS WILL BE
AROUND 40 DEGREES ALONG THE WI BORDER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM EST MON MAR 4 2013
VFR CONDITIONS AT KSAW AND KCMX WILL GIVE WAY TO MVFR CIGS BY LATE
MORNING AS AN E-NE FLOW BRINGS MASS OF STRATOCU LAKE CLOUDS INLAND.
MODEL FCST SOUNDINGS SUGGEST THESE CLOUDS COULD PERSIST THROUGH REST
OF TAF PD IN CONTINUED E-NE FLOW. AT KIWD...MID LVL CLOUDS WILL MOVE
IN THIS MORNING AND CLOUDS WILL CONTINUE TO LOWER TONIGHT AS SYSTEM
OVER THE NRN PLAINS BRUSHES JUST SOUTH AND WEST OF THE REGION.
HOWEVER...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE PD AT KIWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EST MON MAR 4 2013
STRONGEST WINDS THIS WEEK OCCUR THIS AFTERNOON THROUGH TUESDAY OVER
FAR WESTERN LAKE SUPERIOR AS A LOW PRESSURE SYSTEM MOVES JUST TO THE
SOUTH. EAST-NORTHEAST WINDS TO 30 KTS ARE A GOOD BET. MAY BE GALE
GUSTS TOWARD THE HEAD OF LK SUPERIOR AND ALONG THE MINNESOTA SHORE
MONDAY NIGHT INTO TUESDAY MORNING DUE TO COASTAL CONVERGENCE. NORTH
WINDS TO 25 KTS CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY
WINDS AND COLDER TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT
TIMES THROUGH WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WEDNESDAY INTO FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
502 AM EST MON MAR 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EST MON MAR 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHORTWAVE TROUGH
OVER ERN MONTANA WITH A MID/UPPER LEVEL RIDGE EXTENDING FROM THE
PLAINS INTO THE UPPER GREAT LAKES. AT THE SFC...A RIDGE EXTENDED
FROM NRN MANITOBA INTO WRN UPPER MI. SHALLOW LOW-LVL MOISTURE AIDED
BY CONTRIBUTION OFF LAKE SUPERIOR IN NNE FLOW HAS GENERATED SOME
LAKE CLOUDS FOR AREAS EAST OF MQT. LACK OF RADAR RETURNS EARLY THIS
MORNING SUGGEST LTL MORE THAN FLURRIES ASSOC WITH THESE LAKE CLOUDS.
CLEAR SKIES OVER THE WEST HALF HAS RESULTED IN TEMPS FALLING INTO
THE SINGLE DIGITS BLO ZERO AT MANY LOCATIONS EARLY THIS MORNING.
TODAY...WEAK UPSLOPE NE FLOW INTO N CNTRL UPPER MI MAY GENERATE SOME
FLURRIES DESPITE INVERSION HEIGHTS BELOW 3K FT. WITH LOW CONFIDENCE
IN ANY MEASURABLE LES...HAVE DROPPED MENTION OF SLIGHT CHANCE POPS.
WITH ANTICYCLONIC/DIFLUENT ENE FLOW...ANY FLURRIES THAT FORM SHOULD
END BY MIDDAY. LOOK FOR MAX TEMPS TO REBOUND INTO THE UPPER 20S AND
LOWER 30S...PER FCST SOUNDINGS LOW LEVEL TEMP PROFILE.
TONIGHT...MODELS CONSISTENT IN SHOWING ERN MT SHORTWAVE DIVING WELL
SE OF THE UPPER GREAT LAKES LATER TONIGHT. WITH BEST Q-VECT CONV AND
WAA/ISENTROPIC LIFT STAYING GENERALLY SE OF FCST AREA ALONG TRACK OF
SHORTWAVE AND ASSOC INVERTED SFC TROUGH...MUCH OF CWA SHOULD STAY
DRY THROUGH TONIGHT UNDER INFLUENCE OF SFC HIGH PRESSURE RIDGE. KEPT
ONLY SLIGHT CHC POPS IN FCST OVER FAR WRN LAKE SUPERIOR LATE
TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 501 AM EST MON MAR 4 2013
AT 12Z TUE AN UPPER ANS SFC RIDGE WILL BE OVER THE ERN CWA...BUT
WILL SHIFT E AS AN UPPER TROUGH MOVES IN FROM THE W. THE UPPER
TROUGH WILL MOVE E OF THE CWA BY 00Z THU...BRINGING IN COLDER
INVERSION TOP TEMPS...BETTER SYNOPTIC LIFT AND MORE CYCLONIC
FLOW...WHICH WILL SUPPORT INCREASED LES WITH NE-N LOW LEVEL WINDS
TUE INTO THU. THE BEST COVERAGE AND INTENSITY OF LES IS EXPECTED
TUE/TUE NIGHT...BUT WILL STILL NOT BE ALL THAT HEAVY DUE TO MARGINAL
CONDITIONS AND LOW SNOW TO LIQUID RATIOS. THE SOUTHERN PART OF THE
UPPER TROUGH WILL BE CLOSED OFF AND WILL MOVE WELL S OF THE CWA ON
TUE...WITH SOME SYNOPTIC SNOW POSSIBLY CLIPPING THE IRONWOOD AREA
TUE...BUT ONLY MINOR SNOWFALL AMOUNTS WOULD BE POSSIBLE. WOULD
EXPECT LES TO TAPER OFF AND END WHEN WINDS TURN SLY THU AS A SFC
RIDGE MOVES THROUGH...BUT WARMING TEMPS AND ANTICYCLONIC FLOW WILL
KEEP LES FROM FORMING OFF LAKE MICHIGAN.
EXPECT A COUPLE OF SHORTWAVES TO MOVE NEARBY FRI AND SAT...BUT DO
NOT EXPECT MUCH IN THE WAY OF PRECIP...ESPECIALLY WHEN LOOKING AT
THE MORE CONTINUITOUS ECMWF AND GEM MODELS AS THE GFS DOES PUMP OUT
A GOOD AMOUNT OF PRECIP SAT INTO SUN. PREFERRED THE NON-GFS
SOLUTIONS FOR THIS PART OF THE FORECAST. THEN EXPECT SFC RIDGING TO
MOVE IN ON SUN.
TEMPS WILL GENERALLY BE ON THE RISE...WITH HIGHS AOA FREEZING IN
MOST LOCATIONS FROM THU ON. FOR THE WEEKEND...HIGH TEMPS WILL BE
AROUND 40 DEGREES ALONG THE WI BORDER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 119 AM EST MON MAR 4 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FCST PERIOD WITH A SURFACE
RIDGE DOMINATING THE WEATHER IN THE NORTHERN GREAT LAKES. ONLY
EXCEPTION WILL BE AT SAW WITH SOME LAKE EFFECT UPSLOPE MVFR CLOUDS
IN FOR THIS MORNING...BEFORE BURNING OFF AGAIN IN THE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EST MON MAR 4 2013
STRONGEST WINDS THIS WEEK OCCUR THIS AFTERNOON THROUGH TUESDAY OVER
FAR WESTERN LAKE SUPERIOR AS A LOW PRESSURE SYSTEM MOVES JUST TO THE
SOUTH. EAST-NORTHEAST WINDS TO 30 KTS ARE A GOOD BET. MAY BE GALE
GUSTS TOWARD THE HEAD OF LK SUPERIOR AND ALONG THE MINNESOTA SHORE
MONDAY NIGHT INTO TUESDAY MORNING DUE TO COASTAL CONVERGENCE. NORTH
WINDS TO 25 KTS CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY
WINDS AND COLDER TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT
TIMES THROUGH WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WEDNESDAY INTO FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
930 AM EST MON MAR 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRIEFLY BUILD OVER THE CAROLINAS TODAY.
A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE CAROLINAS AND SOUTHERN
VIRGINIA TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
LITTLE CHANGE TO THE FORECAST FOR TODAY. NC LIES BETWEEN A SURFACE
LOW OVER MAINE AND WEAK HIGH PRESSURE OVER THE EASTERN GOMEX.
CLEAR SKIES WILL CONTINUE EAST OF THE MOUNTAINS WITH PW NEAR 0.10"
IN THE WAKE OF A VORT MAX EXITING THE NC COAST. RAP SOUNDINGS
SUGGEST WIND GUSTS TO AROUND 20MPH THIS MORNING SHOULD WEAKEN AFTER
18Z...SO HAVE ADJUSTED GUSTS DOWNWARD THIS AFTERNOON. GUIDANCE IS
IN GOOD AGREEMENT ON HIGHS OF 49-52 NORTH TO SOUTH. -SMITH
TONIGHT...MID LEVEL S/W RIDGE AND ATTENDANT SURFACE RIDGE WILL SCOOT
ACROSS THE FORECAST AREA. THE APPROACH OF A STRONG UPPER LEVEL LOW
DROPPING SEWD FROM THE UPPER MIDWEST WILL INCREASE/THICKEN CLOUD
COVER BY LATE EVENING-OVERNIGHT HOURS. GFS SPITS PUT A FEW
HUNDREDTHS IN THE NW PIEDMONT BY MORNING. THIS LOOKS OVERDONE
CONSIDERING THE DEGREE OF DRY AIR BELOW THE CLOUD BASE AND WEAK OR
NON-EXISTENT ISENTROPIC LIFT THROUGH 12Z TUE. FAVOR MIN TEMPS
LOW-MID 30S IN THE WEST AND FAR SOUTH WHERE CLOUDS EXPECTED TO BE
THICKER SOONER...TO AROUND 30 IN THE FAR EAST-NE WHERE THINNER CLOUD
COVER EXPECTED UNTIL MIDNIGHT OR SO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 420 AM MONDAY...
QUICK UPDATE BELOW TO WEDNESDAY PERIOD FOR WINDS.
TUESDAY AND TUESDAY NIGHT...
THE APPROACH OF A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL CAUSE
WEATHER CONDITIONS TO DETERIORATE ACROSS CENTRAL NC TUESDAY. THE
APPROACH OF THIS SYSTEM WILL ENHANCE THE 850MB SLY FLOW BY MID DAY
AND CONTINUE THROUGH THE AFTERNOON HOURS. RAIN INITIALLY FALLING
THROUGH THE DRY SUB-CLOUD LAYER WILL LEAD TO EVAPORATIVE COOLING AND
AN IN-SITU CAD EVENT ACROSS THE FAR NORTHERN PIEDMONT. THIS CAD
SHOULD BE QUITE SHALLOW AND MAY BE EASILY SCOURED OUT BY
STRENGTHENING LOW LEVEL SLY FLOW. DO NOT EXPECT MAX TEMPS FOR THE
DAYLIGHT HOURS TO OCCUR ACROSS THE FAR NORTHERN COUNTIES UNTIL CLOSE
TO SUNSET. MOS GUIDANCE APPEARS TOO WARM CONSIDERING THE POTENTIAL
FOR THE IN-SITU CAD...BUT DID ADJUST MAX TEMPS UP 3-5 DEGREES FROM
PREVIOUS FORECAST.
NEAR TERM MODEL GUIDANCE IN GENERAL AGREEMENT ON THE PLACEMENT OF
850MB WARM FRONT ACROSS THE NORTHERN PIEDMONT INTO THE NORTHERN
COASTAL PLAIN LATE TUESDAY AFTERNOON-TUESDAY EVENING. EXPECT AXIS
OF MODERATE RAIN TO SET-UP ALONG THIS FEATURE. FARTHER
SOUTH...EXPECT PRECIP TO BE MORE SHOWERY IN NATURE. MID LEVEL LAPSE
RATES STILL INCREASE TO AROUND 7 DEG C/KM BY 00Z WED. THUS THE IDEA
OF ELEVATED CONVECTION LATE TUESDAY INTO TUESDAY EVENING STILL
APPEARS PROBABLE...ESPECIALLY TUESDAY EVENING WHEN MID LEVEL TROUGH
AND SFC LOW TRAVERSES THE REGION. WHILE KINEMATICS SUPPORTIVE OF THE
POTENTIAL FOR STRONG CONVECTION...LACK OF SURFACE BASED INSTABILITY
WILL LIMIT SEVERE WEATHER ATTRIBUTES WITH THE CONVECTION AT THIS
TIME.
WILL MAINTAIN FORECAST CONTINUITY OF GREATER PRECIP CHANCES TUESDAY
AFTERNOON AND TUESDAY NIGHT WITH LIKELY TO CATEGORICAL POPS DURING
THIS PERIOD. DID GO WITH A SLIGHTLY SLOWER PRECIP ARRIVAL
TUESDAY MORNING. AS SYSTEM BEGINS TO DEPART THE REGION TOWARD
DAYBREAK WEDNESDAY...SHARPLY COLDER AIR ALOFT WILL BRING A THREAT OF
RAIN MIXED WITH SNOW TO THE NW PIEDMONT. -WSS
WEDNESDAY AND WEDNESDAY NIGHT:
MODELS ARE COMING INTO BETTER AGREEMENT ON WEDNESDAY... SHOWING THE
SURFACE LOW INVOF THE NC/VA BORDER NEAR THE COASTAL REGION BY 12Z
WEDNESDAY... WITH THE 500 MB LOW QUICKLY MOVING ACROSS OUR AREA AND
INTO THE SAME GENERALLY AREA BY 18Z WEDNESDAY. THE GFS/NAM/ECMWF
HAVE TRENDED A BIT DRIER ACROSS THE AREA ON WEDNESDAY (WITH LITTLE
IF ANY PRECIP ACROSS THE SOUTHWEST NOW AFTER 12Z)... WITH THE SLIGHT
JOG TO THE NORTH WITH THE TRACK OF THE LOW... ALLOWING MORE OF A
DRYING NW TO NORTHERLY FLOW IN THE WAKE OF THE PASSING MID LEVEL
LOW. HOWEVER... IT STILL APPEAR LIKELY THAT WE WILL SEE SOME PRECIP
FILL BACK IN ACROSS THE NORTHEASTERN HALF OF THE CWA WITH STEEPENING
LAPSE RATES AND A POSSIBLE DEFORMATION BAND EXTENDING ACROSS OUR
NORTH/NORTHEAST (WITH THE MORE SIGNIFICANT PRECIP TO THE
NORTH/NORTHEAST OF OUR AREA). THE GFS BEGINS TO SHOW SIGNS OF THE
SYSTEM LIFTING OFF/MEANDERING MORE NORTH/NORTHEASTWARD WEDNESDAY
AFTERNOON/NIGHT. FOR THIS REASON HAVE ELECTED TO GO WITH MORE OF A
BLEND OF THE NAM/ECMWF FOR POPS/QPF LATE WEDNESDAY MORNING THROUGH
WEDNESDAY NIGHT... AS WE THINK THE BLOCKING HIGH ALOFT ACROSS SE
CANADA SHOULD HELP PREVENT A MORE NORTH/NORTHEASTWARD TRACK (WHICH
THE GFS HAS). THUS... WITH LOW LEVEL THICKNESS CRASHING AND
SUPPORTIVE OF ALL SNOW ACROSS THE NORTHEASTERN HALF (WHERE PRECIP IS
EXPECTED AND SATURATION RETURNING INTO THE -10 TO -20 LAYER C) OF
CENTRAL NC WE MAY SEE SOME ACCUMULATING SNOW (POSSIBLY AT FIRST
MIXED WITH RAIN... DEPENDING ON TEMPS IN THE BOUNDARY LAYER AND
LOCATIONS OF THE DEFORMATION BAND ALONG WITH SATURATION ALOFT)...
ESPECIALLY ACROSS THE FAR NORTHEASTERN PIEDMONT AND NORTHERN COASTAL
PLAIN. GIVEN WE ARE STILL TALKING ABOUT THE MAIN TIME FRAME FOR
ACCUMULATING SNOWFALL BEING WEDNESDAY MID/LATE MORNING INTO THE
AFTERNOON/EARLY EVENING WE WILL NOT ISSUE A WINTER STORM WATCH AT
THIS TIME. HOWEVER... IF FORECAST MODELS CONTINUE TO INDICATE THE
DEFORMATION BAND PIVOTING THROUGH OUR NORTH/NORTHEASTERN COUNTIES
THEN A WINTER STORM WATCH MAYBE NEEDED IN FUTURE FORECAST WITH THE
POTENTIAL FOR SOME DECENT ACCUMULATIONS NORTH OF A LINE FROM ROXBORO
TO LOUISBURG TO ROCKY MOUNT. IN ADDITION TO THE THREAT OF SNOW...
WNW TO NW WINDS WILL STRENGTHEN AS AS THE SYSTEM DEEPENS AND BECOMES
MORE VERTICALLY STACKED ON WEDNESDAY. THUS... THINK WE COULD SEE
WINDS IN THE 20 TO 25 MPH RANGE SUSTAINED... WITH GUSTS AS HIGH AS
30 TO 35 MPH WEDNESDAY... WHICH COULD CREATE LOW VISBYS IN AREAS OF
SNOW. HIGH TEMPS WILL BE QUITE DIFFICULT... WITH THE PRECIP ACROSS
THE NORTHEAST... WITH SKIES EVEN BEGIN TO CLEAR OUT A BIT ACROSS THE
FAR SOUTHWEST LATE IN THE DAY. THIS WILL YIELD A NON-DIURNAL TREND.
THIS YIELDS HIGH TEMPS RANGING FROM THE MID TO UPPER 30S
NORTH/NORTHEAST TO MID TO UPPER 40S SOUTH/WEST. SKIES WILL BEGIN TO
SLOWLY CLEAR FROM SOUTHWEST TO NORTHEAST ON THURSDAY MORNING... WITH
POSSIBLY THE TREAT OF SOME BLACK ICE. EXPECT LOW TEMPS TO RANGE FROM
THE LOWER TO MID 30S. -BSD
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 AM MONDAY...
THE DEEP LOW PRESSURE SYSTEM (WHICH IS EXPECTED TO MOVE ACROSS THE
REGION TUESDAY INTO WEDNESDAY) WILL SHIFT SLOWLY OFF TO THE EAST OF
THE AREA LATE WEEK... WHILE SURFACE HIGH PRESSURE BUILDS INTO THE
AREA AND HEIGHTS ALOFT RISE. SUBSIDENCE BEHIND THE EXITING SYSTEM
WILL PROVIDE THE AREA WITH SUNNY TO MOSTLY SUNNY SKIES FOR LATE
WEEK. HOWEVER... GIVEN THE NORTHERLY/NORTHWESTERLY FLOW... WITH AT
TIME BREEZE SURFACE WINDS ON THURSDAY... EXPECT TEMPS WILL REMAIN
BELOW NORMAL THROUGH AT LEAST THURSDAY AND FRIDAY. THUS... WILL GO
WITH HIGHS RANGING FROM GENERALLY THE UPPER 40S TO MID 50S THURSDAY
TO THE MID TO UPPER 50S FRIDAY. LOWS DURING THIS TIME AREA EXPECTED
TO BE IN THE UPPER 20S TO LOWER 30S (FRIDAY AND SATURDAY MORNINGS).
THE SURFACE RIDGE AXIS IS EXPECTED TO SHIFT TO THE EAST OF THE AREA
ON SATURDAY... YIELDING WARMING CONDITIONS... WITH THE NEXT
SIGNIFICANT SYSTEM EXPECTED TO REMAIN TO THE WEST OF THE AREA
THROUGH THE END OF THE FORECAST PERIOD. THUS... WILL CONTINUE DRY
CONDITIONS... WITH WARMING TEMPS. HOWEVER... EXPECTED CLOUD COVER TO
INCREASE DURING THE LATTER HALF OF THE WEEKEND AS THE NEXT SYSTEM
APPROACHES... ALONG WITH POSSIBLY SOME MID AND HIGH LEVEL CLOUD
COVER ASSOCIATED WITH A PASSING NORTHERN STREAM SYSTEM. THIS YIELDS
EXPECTED HIGH TEMPS NEAR NORMAL ON SATURDAY TO LOWER TO MID 60S
SUNDAY... WITH LOW TEMPS SUNDAY MORNING IN THE UPPER 30S TO AROUND
40.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 618 AM MONDAY...
WEAK HIGH PRESSURE BUILDING INTO CENTRAL NC WILL BE ACCOMPANIED BY
DRY AIR...LEADING TO CLEAR SKIES AND A PERSISTENT NW WIND. WIND
GUSTS THIS MORNING WILL BE 18-23KTS OUT OF THE NW. GUSTS WILL BECOME
INFREQUENT BY THIS AFTERNOON...SUBSIDING AND MAINLY WLY BY THE END
OF THE DAY. THERE WILL BE AN INCREASE IN HIGH LEVEL CLOUDS
CLOUDINESS BY MID-LATE AFTERNOON. WHILE SKIES WILL BECOME OVERCAST
TONIGHT...CEILINGS WILL REMAIN VFR.
AVIATION CONDITIONS WILL DETERIORATE TUESDAY AS A STRONG LOW
PRESSURE SYSTEM BEGINS TO EXERT ITS INFLUENCE ON THE SENSIBLE
WEATHER ACROSS CENTRAL NC. AREAS OF RAIN WILL DEVELOP ACROSS CENTRAL
NC BY LATE TUESDAY MORNING...CONTINUING INTO TUESDAY NIGHT. CEILINGS
WILL BECOME LOW END MVFR/IFR BY TUESDAY AFTERNOON WITH AREAS OF LIFR
PROBABLE TUESDAY NIGHT.
A BREAK IN THE RAIN IS EXPECTED WEDNESDAY MORNING WHICH MAY ALSO SEE
CEILINGS BRIEFLY LIFT INTO THE VFR CATEGORY. ANOTHER ROUND OF
PRECIP ALONG WITH MVFR CEILINGS WILL LIKELY EFFECT THE REGION
WEDNESDAY AFTERNOON WITH THE POTENTIAL FOR THE RAIN TO BECOME MIXED
WITH SNOW PRIOR TO ENDING LATE WEDNESDAY INTO WEDNESDAY EVENING.
WINDY CONDITIONS WILL ALSO AFFECT THE REGION WEDNESDAY THROUGH
WEDNESDAY NIGHT WITH SUSTAINED WINDS NEAR 20 MPH AND GUSTS 30 TO 35
MPH.
VFR CONDITIONS ARE ANTICIPATED THURSDAY INTO FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
559 AM CST MON MAR 4 2013
.DISCUSSION.../ISSUED AT 410 AM CST/
CURRENT SATELLITE AND RADAR VERY EARLY THIS MORNING SHOWING A DRY
SLOT OVERSPREADING OUR AREA WITH THE ONLY RADAR RETURNS BEING
CONFINED TO OUR FAR NORTHEAST FROM MARSHALL TO JACKSON. IN LIGHT OF
THIS...CUT BACK A GOOD BIT ON POPS THROUGH THE MORNING HOURS WITH
PRECIPITATION REDEVELOPMENT PROBABLY NOT OCCURRING UNTIL THE UPPER
LEVEL WAVE PRESENTLY OVER EASTERN MONTANA BEGINS TO DROP
SOUTHEASTWARD...EXERTING INFLUENCE ON OUR AREA BY AFTERNOON. HAVE
HAD SOME VERY LIGHT FREEZING RAIN AND DRIZZLE OVER PORTIONS OF OUR
NORTHERN AND EASTERN AREAS OVERNIGHT...AND WITH STRATUS OOZING INTO
THE AREA FROM THE NORTHWEST CANNOT RULE OUT PATCHY FREEZING DRIZZLE
IN SOME LOCALES DURING THE MORNING. IN LIGHT OF THE ABOVE
TRENDS...READJUSTED CURRENT HEADLINES BY DROPPING THE WESTERN AND
SOUTHERN PORTIONS OF OUR ADVISORY THAT WENT THROUGH 18Z WITH LITTLE
ELSE EXPECTED...BUT KEPT THE ADVISORY OVER OUR NORTHEASTERN CWA
THOUGH EXTENDING IT 6 HOURS...12Z TO 18Z TUESDAY...WITH LIGHT SNOW
PERSISTING OVER THAT AREA INTO THAT TIME FRAME. THE PRECIPITATION
POTENTIAL WILL PICK UP IN OUR EAST BY THIS AFTERNOON INTO THIS
EVENING AS LIFT INCREASES OVER THAT AREA AS THE AFOREMENTIONED UPPER
LEVEL WAVE TRACKS ACROSS THE REGION. TEMPERATURES ALOFT WILL SUPPORT
SNOW BY THAT POINT...THOUGH AREAS ALONG THE WESTERN AND SOUTHERN
FRINGES OF THE PRECIPITATION SHIELD COULD BE MIXED WITH OR BE IN THE
FORM OF PLAIN RAIN WITH SURFACE TEMPERATURES IN THE MID AND UPPER
30S.
THE CRUX OF THE BETTER LIFT WILL BE LOCATED THROUGH OUR NORTHEASTERN
ZONES TONIGHT INTO EARLY ON TUESDAY PER UPPER LEVEL DIV Q
FIELDS...AND THIS IS WHEN MOST OF THE SNOW WILL OCCUR OVER THAT
AREA. STILL LOOKING AT 2 TO 4 INCHES OF ACCUMULATION OVER THE
ADVISORY AREA...GENERALLY IN A LINE FROM BROOKINGS TO SPENCER
EASTWARD. IN ADDITION...NORTHWESTERLY WINDS WILL PICK UP OVERNIGHT
WITH STRONG COLD AIR ADVECTION AND A TIGHTENING GRADIENT ON THE
BACKSIDE OF THE EXITING INVERTED SURFACE TROUGH. THE STRONGEST WINDS
LOOK TO BE ALONG THE MISSOURI RIVER CORRIDOR...AND KEPT THE WIND
ADVISORY...THOUGH EXPANDED SLIGHTLY...FOR THAT AREA STARTING EARLY
TONIGHT AND GOING THROUGH 18Z ON TUESDAY. WITH THE COLD AIR
ADVECTION WE WILL HAVE FALLING TEMPERATURES...THOUGH READINGS WILL
REMAIN IN CHECK WITH THE STRONG WINDS...BOTTOMING OUT IN THE UPPER
TEENS TO LOWER 20S BY EARLY TUESDAY MORNING.
FORCING AND ANY DEEPER MOISTURE PULL AWAY FROM THE AREA ON
TUESDAY...WITH SNOW DIMINISHING IN OUR EAST THROUGH THE MORNING AND
EARLY AFTERNOON HOURS. WITH DECREASING CLOUDS IN THE AFTERNOON UNDER
THE INFLUENCE OF SUBSIDENCE AS HIGH PRESSURE BUILDS INTO OUR WEST.
HIGHS LOOK TO BE IN THE 20S. THE SURFACE RIDGE AXIS SLIDES ACROSS
OUR CWA ON TUESDAY NIGHT...AND WITH DYING WINDS AND CLEARING SKIES
IT WILL BE A COLD NIGHT. LOWS WILL RANGE FROM THE LOWER SINGLE
DIGITS IN OUR NORTHEAST WHERE FRESH SNOW COVER WILL RESIDE...TO JUST
ABOVE 10 ALONG THE MISSOURI RIVER CORRIDOR.
A SOUTHERLY FLOW RETURNS TO THE REGION ON WEDNESDAY AS HIGH PRESSURE
PUSHES OFF TO THE EAST. WITH WARMING THERMAL PROFILES HIGHS WILL
APPROACH 40 IN OUR SOUTH CENTRAL SOUTH DAKOTA ZONES...TAPERING
DOWNWARD TO THE NORTH AND EAST WITH HIGHS ONLY IN THE LOWER 20S IN
OUR SOUTHWESTERN MINNESOTA AREAS WHICH WILL HAVE DEEPER SNOW COVER.
LONG RANGE THURSDAY THROUGH SUNDAY STARTS OFF WITH FAIRLY GOOD
AGREEMENT AMONG THE MODELS...SHOWING LONG WAVE RIDGE IN PLACE ACROSS
THE AREA WITH WEAK NORTHERN STREAM SHORTWAVE TOPPING THE RIDGE NORTH
OF THIS FORECAST AREA. MILD LOW LEVEL AIR IN PLACE WITH 850MB TEMPS
ABOVE 0C THROUGH FRIDAY WILL BRING TEMPERATURES CLOSER TO SEASONAL
NORMALS THAN WE HAVE SEEN OF LATE...WITH AREAS WEST OF THE JAMES
RIVER MOST LIKELY TO SEE READINGS CLIMB WELL ABOVE NORMAL THURSDAY.
CONFIDENCE DECREASES SIGNIFICANTLY IN THE LATTER PART OF THE PERIOD
AS MODELS SHOW MUCH GREATER DIVERGENCE IN HANDLING STRONG SOUTHERN
STREAM TROUGH WHICH DIGS THROUGH THE DESERT SOUTHWEST LATE THIS
WEEK. ECMWF SWINGING A CUTOFF LOW OUT INTO THE CENTRAL PLAINS NEXT
WEEKEND...WITH 04/00Z RUN STRONGER/FARTHER NORTH THAN 03/12Z RUN...
THOUGH BOTH WOULD PRODUCE A PERIOD OF SIGNIFICANT PRECIPITATION
ACROSS THIS AREA AT SOME POINT NEXT WEEKEND. OPERATIONAL GFS...ON
THE OTHER HAND...KICKS ONE PIECE OF ENERGY INTO THE PLAINS FOR
SATURDAY...BUT OTHERWISE HOLDS MAIN UPPER TROUGH OVER THE DESERT
SOUTHWEST WITH LARGELY DRY CONDITIONS FOR THE LATTER HALF OF THE
WEEKEND. GFS ENSEMBLE NOT MUCH HELP AS ITS MEAN IS MORE PROGRESSIVE
BUT MUCH FARTHER SOUTH THAN ECMWF WITH CLOSED LOW KICKING OUT INTO
THE SOUTHERN PLAINS...KEEPING PRIMARY PRECIPITATION THREAT SOUTH OF
THIS AREA. GIVEN THE DISPARITY IN SOLUTIONS AT THIS RANGE...WILL NOT
VARY MUCH OF BROAD MODEL CONSENSUS...WHICH HOLDS ONTO A SMALL CHANCE
OF PRECIP ACROSS OUR SOUTH FRIDAY NIGHT THROUGH SATURDAY NIGHT...
FOLLOWED BY SLIGHTLY GREATER CHANCES SPREADING FARTHER NORTH ACROSS
THE FORECAST AREA ON SUNDAY. TEMPERATURES WILL LIKEWISE BE HELD NEAR
CONSENSUS...WHICH IS GENERALLY ON THE COOL SIDE OF NORMAL WITH HIGHS
IN THE 30S/AROUND 40...BUT VARIANCE IN SOLUTIONS LEADS TO ADDITIONAL
CONCERNS REGARDING PRECIPITATION TYPE...AND WILL KEEP THIS RATHER
GENERIC WITH CHANCE OF RAIN OR SNOW WORDING THROUGHOUT THE PERIOD.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
LARGELY MVFR STRATUS BEGINNING TO SPREAD BACK ACROSS WESTERN PARTS
OF FORECAST AREA WHILE EASTERN AREAS REMAIN UNDER LINGERING MVFR/IFR
CEILINGS. RAP CONTINUES TO HAVE BEST GRASP ON NEAR TERM MOISTURE AND
PRECIPITATION TRENDS...AND ASIDE FROM NARROW BAND OF SHOWERY PRECIP
RIGHT ALONG A WIND SHIFT LINE ENTERING FAR WESTERN FORECAST AREA
WHICH COULD AFFECT KHON AT THE START OF THE PERIOD...EXPECT LARGELY
DRY FORECAST FOR THE TAF SITES THROUGH THE DAY. HOWEVER...AS THIS
FEATURE TRANSLATES EAST INTO I-29 CORRIDOR...MID LEVEL MOISTURE
BECOMES MORE SCARCE... BUT ENOUGH WEAK LIFT PERSISTS ABOVE STRATUS
DECK THAT WILL KEEP BRIEF PERIOD OF POTENTIAL FREEZING DRIZZLE
AROUND KFSD LATER IN THE MORNING. MID LEVEL MOISTURE INCREASES EAST
OF I-29...BRINGING GREATER CHANCE OF MVFR-OCCASIONAL IFR VISIBILITY
IN -SN TO SOUTHWEST MINNESOTA THIS AFTERNOON. BETTER CHANCE FOR SOME
LIGHT SNOWFALL RETURNS TO TAF SITES AFTER THIS EVENING...AS MOISTURE
WRAPS BACK INTO AREA BEHIND EXITING WAVE. GREATER AVIATION CONCERN
FOR LATTER PART OF THE PERIOD WILL BE INCREASING WINDS BEHIND THE
SYSTEM...ESPECIALLY THROUGH THE JAMES AND WESTERN MISSOURI RIVER
CORRIDOR BY VERY LATE AFTERNOON...EXPANDING EASTWARD IN THE EVENING.
SURFACE WIND GUSTS OF 25 TO 35 KNOTS LIKELY DURING THE LATER EVENING
AND OVERNIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
SDZ050-052-057>060-063>066-068>071.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR SDZ040-056.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR SDZ039-055-062.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR MNZ071-072-
080-081-089-090-097.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ098.
IA...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
IAZ031.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR IAZ002-003-
014.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ001.
NE...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
NEZ013-014.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
410 AM CST MON MAR 4 2013
.DISCUSSION...ISSUED AT 410 AM CST/
CURRENT SATELLITE AND RADAR VERY EARLY THIS MORNING SHOWING A DRY
SLOT OVERSPREADING OUR AREA WITH THE ONLY RADAR RETURNS BEING
CONFINED TO OUR FAR NORTHEAST FROM MARSHALL TO JACKSON. IN LIGHT OF
THIS...CUT BACK A GOOD BIT ON POPS THROUGH THE MORNING HOURS WITH
PRECIPITATION REDEVELOPMENT PROBABLY NOT OCCURRING UNTIL THE UPPER
LEVEL WAVE PRESENTLY OVER EASTERN MONTANA BEGINS TO DROP
SOUTHEASTWARD...EXERTING INFLUENCE ON OUR AREA BY AFTERNOON. HAVE
HAD SOME VERY LIGHT FREEZING RAIN AND DRIZZLE OVER PORTIONS OF OUR
NORTHERN AND EASTERN AREAS OVERNIGHT...AND WITH STRATUS OOZING INTO
THE AREA FROM THE NORTHWEST CANNOT RULE OUT PATCHY FREEZING DRIZZLE
IN SOME LOCALES DURING THE MORNING. IN LIGHT OF THE ABOVE
TRENDS...READJUSTED CURRENT HEADLINES BY DROPPING THE WESTERN AND
SOUTHERN PORTIONS OF OUR ADVISORY THAT WENT THROUGH 18Z WITH LITTLE
ELSE EXPECTED...BUT KEPT THE ADVISORY OVER OUR NORTHEASTERN CWA
THOUGH EXTENDING IT 6 HOURS...12Z TO 18Z TUESDAY...WITH LIGHT SNOW
PERSISTING OVER THAT AREA INTO THAT TIME FRAME. THE PRECIPITATION
POTENTIAL WILL PICK UP IN OUR EAST BY THIS AFTERNOON INTO THIS
EVENING AS LIFT INCREASES OVER THAT AREA AS THE AFOREMENTIONED UPPER
LEVEL WAVE TRACKS ACROSS THE REGION. TEMPERATURES ALOFT WILL SUPPORT
SNOW BY THAT POINT...THOUGH AREAS ALONG THE WESTERN AND SOUTHERN
FRINGES OF THE PRECIPITATION SHIELD COULD BE MIXED WITH OR BE IN THE
FORM OF PLAIN RAIN WITH SURFACE TEMPERATURES IN THE MID AND UPPER
30S.
THE CRUX OF THE BETTER LIFT WILL BE LOCATED THROUGH OUR NORTHEASTERN
ZONES TONIGHT INTO EARLY ON TUESDAY PER UPPER LEVEL DIV Q
FIELDS...AND THIS IS WHEN MOST OF THE SNOW WILL OCCUR OVER THAT
AREA. STILL LOOKING AT 2 TO 4 INCHES OF ACCUMULATION OVER THE
ADVISORY AREA...GENERALLY IN A LINE FROM BROOKINGS TO SPENCER
EASTWARD. IN ADDITION...NORTHWESTERLY WINDS WILL PICK UP OVERNIGHT
WITH STRONG COLD AIR ADVECTION AND A TIGHTENING GRADIENT ON THE
BACKSIDE OF THE EXITING INVERTED SURFACE TROUGH. THE STRONGEST WINDS
LOOK TO BE ALONG THE MISSOURI RIVER CORRIDOR...AND KEPT THE WIND
ADVISORY...THOUGH EXPANDED SLIGHTLY...FOR THAT AREA STARTING EARLY
TONIGHT AND GOING THROUGH 18Z ON TUESDAY. WITH THE COLD AIR
ADVECTION WE WILL HAVE FALLING TEMPERATURES...THOUGH READINGS WILL
REMAIN IN CHECK WITH THE STRONG WINDS...BOTTOMING OUT IN THE UPPER
TEENS TO LOWER 20S BY EARLY TUESDAY MORNING.
FORCING AND ANY DEEPER MOISTURE PULL AWAY FROM THE AREA ON
TUESDAY...WITH SNOW DIMINISHING IN OUR EAST THROUGH THE MORNING AND
EARLY AFTERNOON HOURS. WITH DECREASING CLOUDS IN THE AFTERNOON UNDER
THE INFLUENCE OF SUBSIDENCE AS HIGH PRESSURE BUILDS INTO OUR WEST.
HIGHS LOOK TO BE IN THE 20S. THE SURFACE RIDGE AXIS SLIDES ACROSS
OUR CWA ON TUESDAY NIGHT...AND WITH DYING WINDS AND CLEARING SKIES
IT WILL BE A COLD NIGHT. LOWS WILL RANGE FROM THE LOWER SINGLE
DIGITS IN OUR NORTHEAST WHERE FRESH SNOW COVER WILL RESIDE...TO JUST
ABOVE 10 ALONG THE MISSOURI RIVER CORRIDOR.
A SOUTHERLY FLOW RETURNS TO THE REGION ON WEDNESDAY AS HIGH PRESSURE
PUSHES OFF TO THE EAST. WITH WARMING THERMAL PROFILES HIGHS WILL
APPROACH 40 IN OUR SOUTH CENTRAL SOUTH DAKOTA ZONES...TAPERING
DOWNWARD TO THE NORTH AND EAST WITH HIGHS ONLY IN THE LOWER 20S IN
OUR SOUTHWESTERN MINNESOTA AREAS WHICH WILL HAVE DEEPER SNOW COVER.
LONG RANGE THURSDAY THROUGH SUNDAY STARTS OFF WITH FAIRLY GOOD
AGREEMENT AMONG THE MODELS...SHOWING LONG WAVE RIDGE IN PLACE ACROSS
THE AREA WITH WEAK NORTHERN STREAM SHORTWAVE TOPPING THE RIDGE NORTH
OF THIS FORECAST AREA. MILD LOW LEVEL AIR IN PLACE WITH 850MB TEMPS
ABOVE 0C THROUGH FRIDAY WILL BRING TEMPERATURES CLOSER TO SEASONAL
NORMALS THAN WE HAVE SEEN OF LATE...WITH AREAS WEST OF THE JAMES
RIVER MOST LIKELY TO SEE READINGS CLIMB WELL ABOVE NORMAL THURSDAY.
CONFIDENCE DECREASES SIGNIFICANTLY IN THE LATTER PART OF THE PERIOD
AS MODELS SHOW MUCH GREATER DIVERGENCE IN HANDLING STRONG SOUTHERN
STREAM TROUGH WHICH DIGS THROUGH THE DESERT SOUTHWEST LATE THIS
WEEK. ECMWF SWINGING A CUTOFF LOW OUT INTO THE CENTRAL PLAINS NEXT
WEEKEND...WITH 04/00Z RUN STRONGER/FARTHER NORTH THAN 03/12Z RUN...
THOUGH BOTH WOULD PRODUCE A PERIOD OF SIGNIFICANT PRECIPITATION
ACROSS THIS AREA AT SOME POINT NEXT WEEKEND. OPERATIONAL GFS...ON
THE OTHER HAND...KICKS ONE PIECE OF ENERGY INTO THE PLAINS FOR
SATURDAY...BUT OTHERWISE HOLDS MAIN UPPER TROUGH OVER THE DESERT
SOUTHWEST WITH LARGELY DRY CONDITIONS FOR THE LATTER HALF OF THE
WEEKEND. GFS ENSEMBLE NOT MUCH HELP AS ITS MEAN IS MORE PROGRESSIVE
BUT MUCH FARTHER SOUTH THAN ECMWF WITH CLOSED LOW KICKING OUT INTO
THE SOUTHERN PLAINS...KEEPING PRIMARY PRECIPITATION THREAT SOUTH OF
THIS AREA. GIVEN THE DISPARITY IN SOLUTIONS AT THIS RANGE...WILL NOT
VARY MUCH OF BROAD MODEL CONSENSUS...WHICH HOLDS ONTO A SMALL CHANCE
OF PRECIP ACROSS OUR SOUTH FRIDAY NIGHT THROUGH SATURDAY NIGHT...
FOLLOWED BY SLIGHTLY GREATER CHANCES SPREADING FARTHER NORTH ACROSS
THE FORECAST AREA ON SUNDAY. TEMPERATURES WILL LIKEWISE BE HELD NEAR
CONSENSUS...WHICH IS GENERALLY ON THE COOL SIDE OF NORMAL WITH HIGHS
IN THE 30S/AROUND 40...BUT VARIANCE IN SOLUTIONS LEADS TO ADDITIONAL
CONCERNS REGARDING PRECIPITATION TYPE...AND WILL KEEP THIS RATHER
GENERIC WITH CHANCE OF RAIN OR SNOW WORDING THROUGHOUT THE PERIOD.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MODELS AGAIN ARE STRUGGLING MIGHTILY IN DEPICTION OF THE NEAR
SURFACE LAYER...EXHIBITING A VERY STRONG COLD AND HIGH RELATIVE
HUMIDITY BIAS. RAP HAS THE BEST HANDLE ON THIS...AND WOULD SUGGEST
LITTLE PRECIPITATION FOR TAF SITES BEYOND THE IMMEDIATE TERM...AND
THIS TYPE WOULD LIKELY REMAIN LIQUID WITH TEMPS ALOFT FOR TAF
SITES...WITH WET BULB PROCESS TO SNOW IN PRECIPITATION BAND LIFTING
NORTHEAST. AS TEMPERATURES DRY OUT ALOFT TONIGHT BEHIND THE MAIN
BAND...INDICATIONS ARE FOR SOME DEVELOPMENT OF IFR OR LIFR CEILINGS
ALONG WITH DRIZZLE/FREEZING DRIZZLE BY LATER TONIGHT AND INTO MONDAY
MORNING. BRIEF PERIOD WITH SOME MID LEVEL CLOUDINESS AS DIV Q
INCREASES LATER MORNING OR MIDDAY COULD YIELD ICE PROCESS
INTRODUCTION AND THREAT FOR A BRIEF PERIOD OF LIGHT SNOWFALL WITH
MVFR OR IFR VISIBILITY. BETTER THREAT FOR SNOWFALL FOR TAF SITES
LOOKS TO EXIST JUST BEYOND CURRENT FORECAST. WINDS WILL INCREASE
BEHIND THE SYSTEM THROUGH THE JAMES AND WESTERN MISSOURI RIVER
CORRIDOR BY VERY LATE AFTERNOON...EXPANDING EASTWARD IN THE EVENING
BEHIND THE INVERTED TROUGH...WHERE SURFACE WIND GUSTS OF 30 TO 40 KNOTS
LIKELY DURING THE LATER EVENING. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
SDZ050-052-057>060-063>066-068>071.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR SDZ040-056.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR SDZ039-055-062.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR MNZ071-072-
080-081-089-090-097.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ098.
IA...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
IAZ031.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR IAZ002-003-
014.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ001.
NE...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
NEZ013-014.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
547 AM CST MON MAR 4 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
343 AM CST MON MAR 4 2013
FORECAST FOCUS REMAINS ON WINTER STORM IMPACTING THE REGION TODAY
THROUGH TUESDAY.
LATEST WATER VAPOR IMAGERY AND RAP 500 MB ANALYSIS SHOWED A POTENT
LOW CENTERED OVER WESTERN MONTANA. A LEADING SHORTWAVE WAS MOVING
EAST ACROSS WESTERN MINNESOTA/IOWA. A BAND OF LIGHT SNOW EXTENDED
FROM WEST CENTRAL MINNESOTA...SOUTHEAST THROUGH SOUTHEAST
MINNESOTA INTO EASTERN IOWA. VISIBILITIES WITHIN THIS BAND HAD
FALLEN INTO THE 1 TO 2 MILE RANGE.
THE ONGOING BAND OF SNOW WILL CONTINUE MOVING EAST/NORTHEAST THIS
MORNING ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...APPROACHING
THE MISSISSIPPI RIVER DURING THE MID TO LATE MORNING HOURS.
MESOSCALE MODELS SHOW THE BAND REALLY FALLING APART AS IT MOVES
INTO WESTERN WISCONSIN LATE THIS MORNING INTO EARLY THIS AFTERNOON
AND REALLY NOT MAKING IT TO THE INTERSTATE 94 CORRIDOR AS IT
ENCOUNTERS VERY DRY AIR. KEAU FORECAST SOUNDINGS SHOW THE DRY AIR
EXTENDING FROM THE SURFACE THROUGH AROUND 5KFT...SO IT WILL TAKE
SOME TIME FOR SATURATION TO OCCUR. SNOW ACCUMULATIONS TODAY WILL
BE ON THE LIGHT SIDE RANGING FROM 1 TO POSSIBLY 3 INCHES OVER
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA TO AROUND AN INCH OVER FAR
WESTERN WISCONSIN. FRONTOGENESIS INCREASES...IN THE 850-700 MB
LAYER...THIS AFTERNOON RIGHT ALONG THE MISSISSIPPI RIVER. THIS
COULD KEEP LIGHT SNOWFALL INTO THE EARLY AFTERNOON HOURS BEFORE IT
WANES. GFS FORECAST SOUNDINGS THIS AFTERNOON OVER SOUTHEAST
MINNESOTA....NORTHEAST IOWA...AND FAR SOUTHWEST WISCONSIN SHOW A
LOSS OF ICE ALOFT WHICH COULD LEAD TO SOME FREEZING DRIZZLE. THE
NAM ON THE OTHER HAND KEEPS THE ICE ALOFT ACROSS THESE AREAS.
GIVEN THE CONSISTENT SIGNAL FOR A LOSS OF ICE IN THE GFS WILL
INTRODUCE A SLIGHT CHANCE OF FREEZING DRIZZLE ACROSS THESE AREAS
THIS AFTERNOON INTO EARLY THIS EVENING.
THE LOW WILL DIVE SOUTHEAST TONIGHT INTO THE UPPER MISSISSIPPI RIVER
VALLEY. VERY IMPRESSIVE LARGE SCALE FORCING ASSOCIATED WITH THE LOW
WITH DEEP QG FORCING NOTED PARTICULARLY IN THE 700-500 MB LAYER. A
BROAD AREA OF ISENTROPIC LIFT...MAINLY FOCUSED ON THE 280-310 K
SURFACES...WILL DEVELOP ACROSS THE FORECAST AREA THIS EVENING AND
CONTINUE THROUGH THE OVERNIGHT HOURS. SREF PROBABILITIES FOR SNOWFALL
RATES OF AN INCH PER HOUR DEVELOP ACROSS MOST OF THE FORECAST AREA
THIS EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS INTO TUESDAY
MORNING. OVERALL FORECAST MODELS ARE IN CLOSE AGREEMENT THIS CYCLE
PLACING A BROAD SWATH OF HEAVY SNOW ACROSS MUCH OF THE AREA WITH
ACCUMULATIONS RANGING FROM 8 TO 13 INCHES. THE HIGHEST
ACCUMULATIONS WILL BE ALONG THE MISSISSIPPI RIVER...AND INCLUDING
ALL OF SOUTHWEST WISCONSIN. DECIDED TO ISSUE A WINTER STORM
WARNING FOR CENTRAL AND NORTH CENTRAL WISCONSIN STARTING AT 6 PM
THIS EVENING AND CONTINUING THROUGH 6 PM TUESDAY. WILL CONTINUE
THE WINTER STORM WARNING FOR THE REST OF THE FORECAST AREA...BUT
PLAN ON THE BULK OF THE ACCUMULATING SNOW TO OCCUR TONIGHT THROUGH
TUESDAY MORNING. GIVEN THE FORCING OVERNIGHT INTO TUESDAY
MORNING...THE SNOW WILL BE HEAVY AT TIMES ESPECIALLY FOR THE
TUESDAY MORNING COMMUTE. THE SNOW IS EXPECTED TO TAPER OFF FROM
NORTHWEST TO SOUTHEAST LATE TUESDAY AFTERNOON AND FINALLY EXIT THE
AREA TUESDAY NIGHT. THE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA
TUESDAY AFTERNOON INTO TUESDAY EVENING WITH NORTH WINDS INCREASING
TO 10 TO 17 MPH WITH GUSTS AROUND 25 MPH POSSIBLE. WILL HAVE TO
KEEP A CLOSE WATCH ON THE POTENTIAL FOR BLOWING SNOW. ALSO...LOW
TEMPERATURES TUESDAY NIGHT COULD BE CHALLENGING WITH THE FRESH
SNOW PACK AND DECREASING CLOUDS. IF CLOUDS CLEAR EARLIER THAN
FORECAST LOWS COULD BE SEVERAL DEGREES COLDER.
HIGH PRESSURE IS EXPECTED TO BUILD INTO THE REGION ON WEDNESDAY AS
RIDGING INTENSIFIES OVER THE CENTRAL CONUS. PLAN ON PARTLY TO MOSTLY
SUNNY SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WITH HIGHS RANGING
FROM THE LOWER 30S OVER NORTHERN WISCONSIN TO THE MID 20S ACROSS
SOUTHEAST MINNESOTA.
.LONG TERM...THURSDAY THROUGH SUNDAY
343 AM CST MON MAR 4 2013
04.00 MEDIUM RANGE MODELS ARE IN AGREEMENT THURSDAY INTO FRIDAY
SHOWING RIDGING OVER THE UPPER MIDWEST. A SHORTWAVE LOOKS TO PASS
JUST NORTH OF THE AREA ACROSS NORTHERN MINNESOTA THROUGH SOUTHERN
ONTARIO. THIS FEATURE WILL BRING A SLIGHT CHANCE OF SNOW TO FAR
NORTHERN WISCONSIN AS IT MOVES THROUGH THURSDAY NIGHT. MODEL
SOLUTIONS START TO DIVERGE LATE FRIDAY THROUGH THE WEEKEND WITH THE
HANDLING OF AN UPPER LOW OVER THE DESERT SOUTHWEST. THE ECMWF TAKES
THE LOW INTO THE PLAINS ON SATURDAY...LIFTING INTO THE UPPER
MISSISSIPPI RIVER VALLEY SUNDAY INTO MONDAY. THE GFS KEEPS A CUTOFF
LOW OVER THE SOUTHWEST AND BRINGS AN OPEN WAVE ACROSS THE REGION.
GIVEN THE MODEL DIFFERENCES WILL LEAN TOWARD A MODEL CONSENSUS BLEND
THROUGH THE WEEKEND WITH PRECIPITATION CHANCES FRIDAY NIGHT THROUGH
SUNDAY. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW FORECAST
MODEL RUNS SINCE THE SOUTHWEST LOW HAS THE POTENTIAL TO BRING RAIN
AND MUCH WARMER TEMPERATURES TO THE AREA. THE ECMWF WARMS
TEMPERATURES INTO THE 50S ON MONDAY AND BRINGS NEARLY 1/2 INCH OF
RAIN INTO THE AREA. THROUGH THE WEEKEND...PLAN ON TEMPERATURES NEAR
TO SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE UPPER 30S TO AROUND 40.
&&
.AVIATION...TODAY AND TONIGHT
547 AM CST MON MAR 4 2013
SNOW HAS MOVED INTO KRST WITH VISIBILITIES RAPIDLY DROPPING TO
IFR. CEILINGS HAVE ALSO DROPPED QUICKLY TO MVFR. FARTHER TO THE
EAST...DRY AIR CONTINUES TO HOLD STRONG AT KLSE WITH VFR
CONDITIONS IN PLACE.
FOR TODAY...THE BACK EDGE OF THE SNOW WAS JUST TO THE WEST OF
KAEL AS OF 1130Z. THIS SHOULD REACH KRST BY 16Z...ALLOWING
VISIBILITIES TO COME UP TO MVFR OR EVEN VFR. HOWEVER...CEILINGS
ARE GOING TO CONTINUE TO DROP...LIKELY TO IFR BY 16Z. AS THE SNOW
DIMINISHES...SOME FREEZING DRIZZLE MAY OCCUR FOR THE AFTERNOON.
MEANWHILE AT KLSE...DRY AIR SHOULD HOLD THE BAND OF SNOW OFF FOR A
FEW MORE HOURS. AROUND 16Z...ANTICIPATING THE SNOW TO MOVE
IN...THOUGH IT SHOULD BE WEAKER DUE TO THE DRY AIR COMPARED TO
WHAT HAPPENED AT KRST. STILL HAVE VISIBILITIES DROPPING TO
IFR...BUT CEILINGS WILL TAKE A LOT LONGER TO LOWER...ONLY DROPPING
TO MVFR. TOTAL SNOW ACCUMULATIONS TODAY ARE EXPECTED AROUND 2
INCHES AT KRST AND UP TO 1 INCH AT KLSE.
FOR TONIGHT...HEAVIER SNOW IS EXPECTED TO DEVELOP AT BOTH TAF
SITES AS A LOW PRESSURE AREA DROPS SOUTHEAST OUT OF THE DAKOTAS.
VISIBILITIES SHOULD LOWER TO IFR DURING THE EVENING...THEN TO LIFR
OVERNIGHT. CEILINGS ARE ALSO EXPECTED TO LOWER...TO LIFR AT KRST
AND IFR AT KLSE DURING THE EVENING HOURS. PLAN ON TOTAL SNOW
ACCUMULATIONS OF 5 TO 6 INCHES AT BOTH TAF SITES.
LOOKING AHEAD TO TUESDAY...THE HEAVY SNOW MOVING IN TONIGHT LOOKS
TO PERSIST THROUGH THE MORNING HOURS. THEREFORE...DIFFICULT
AVIATION TRAVEL IS ANTICIPATED. WINDS ALSO PICK UP DURING THE
AFTERNOON...ADDING BLOWING SNOW INTO THE MIX. AN ADDITIONAL 4 TO 6
INCHES IS POSSIBLE AT BOTH TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 PM CST SUN MAR 3 2013
WI...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
WIZ032-033-041-053>055-061.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY
AFTERNOON FOR WIZ017-029-034-042>044.
MN...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR MNZ079-086-087-094-095.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
MNZ088-096.
IA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR IAZ008-009-018-019.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
IAZ010-011-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1049 AM MST MON MAR 4 2013
.UPDATE...
&&
.SHORT TERM...PRETTY GOOD BATCH OF SHOWERS DROPPING OUT OF SE
WYOMING WILL MOVE ACROSS THE FRONT RANGE CITIES THIS AFTERNOON.
WEBCAMS SHOW WIDESPREAD LIGHT SNOW ACROSS SE WYOMING THOUGH
CEILINGS HAVE STAYED FAIRLY HIGH. SOME OF THE SHOWERS HAVE
PRODUCED BURSTS OF HEAVY SNOW BUT NOT FOR LONG. EXPECT THIS SAME
WEATHER WILL BE OUR AFTERNOON WEATHER. SUBSTANTIALLY RAISED
POPS...BUT STILL EXPECTED AMOUNTS TO BE UNDER TWO INCHES WITH WET
ROADS IN GENERAL...SOME SLUSHING IN THE HEAVIER SHOWERS. PROSPECT
FOR A FOCUSED PROLONGED SNOW BAND DOES NOT LOOK VERY GOOD AND LOW
LEVELS ARE DEFINITELY DRYING BY LATE AFTERNOON...SO AMOUNTS ON THE
PALMER DIVIDE MAY BE OVERDONE. MOST OF THIS ACTIVITY WILL BE EAST
OF THE MOUNTAINS...SO I WILL GO AHEAD AND LET THE MOUNTAIN
ADVISORIES EXPIRE.
&&
.AVIATION...SNOW SHOWERS EXPECTED BETWEEN 19Z AND 01Z. MVFR
CEILINGS WITH AREAS OF IFR IN THE HEAVIER SHOWERS...BUT ANY HEAVY
SHOWERS SHOULD BE SHORT LIVED. CONDITIONS SHOULD IMPROVE
CONSIDERABLY BETWEEN 00Z AND 03Z WITH VISUAL APPROACHES TO KDEN
AFTER THAT TIME. ACCUMULATIONS UNDER TWO INCHES WITH SOME MELTING
ON THE RUNWAYS.
&&
.PREV DISCUSSION... /ISSUED 411 AM MST MON MAR 4 2013/
SHORT TERM...DIFFICULT FORECAST TODAY. CURRENT SURFACE ANALYSIS
SHOWS COLD FRONT HAS PUSHED INTO THE DENVER METRO AREA. THIS FRONT
IS QUITE SHALLOW...BUT WILL PROVIDE COOLING AND ENOUGH UPSLOPE FOR
POTENTIAL STRATUS AND A FEW LIGHT SNOW SHOWERS THIS MORNING.
HOWEVER...MID/UPPER LEVELS WERE BEGINNING TO SHOW SOME SIGNS OF
DRYING FROM THE NORTH...AS RADAR SHOWS SNOW IN THE NORTHERN FRONT
RANGE MOUNTAINS DECREASING. MEANWHILE...SUMMIT COUNTY CAMS AND
RADAR SHOWS GOOD SNOW CONTINUING IN THE I-70 MOUNTAIN CORRIDOR
WITH POOR TRAVEL CONDITIONS. GJT RADAR SHOWS ANOTHER BATCH OF
HIGHER RETURNS TO PUSH INTO THAT EARLY EARLY THIS MORNING BEFORE A
DECREASE OCCURS LATER. WILL LET THE MOUNTAIN ADVISORIES CONTINUE
TIL NOON. POSSIBLE EXTENSION OF ADVISORIES MAY BE REQUIRED WITH
NEXT SHORT WAVE/SPEED MAX THIS AFTERNOON.
THIS NEXT UPPER LEVEL WAVE CREATES MOST OF THE CHALLENGE WITH
TODAYS FORECAST. CURRENT UPPER LEVEL ANALYSIS SHOWS THIS FEATURE
DROPPING ACROSS IDAHO WITH ENHANCED CLOUDINESS ON THE POLEWARD
SIDE. THIS FEATURE WILL REACH NORTHERN COLORADO THIS AFTERNOON. AT
THE SAME TIME...SOME DEEPENING OF THE UPSLOPE FLOW WILL LIKELY
OCCUR WITH ANOTHER ANTICYCLONIC SURGE FROM THE NORTH. AT THIS
TIME...THIS SHOT OF UPSLOPE APPEARS TO BE SHORT LIVED...BUT ENOUGH
TO PRODUCE SNOW SHOWERS ALONG THE FRONT RANGE AND SOUTH/SOUTHEAST
ACROSS THE PALMER DIVIDE TO LINCOLN COUNTY. THIS COULD PLAY HAVOC
WITH THE AFTERNOON RUSH WITH A QUICK INCH OF SNOW POSSIBLE...BUT
ROADS TEMPS ARE EXPECTED TO BE WARM ENOUGH TO MELT MOST SNOW THAT
FALLS...IF IT SNOWS. WE DO THINK WITH THE QUICK SHOT OF
UPSLOPE...FAVORABLE SURFACE Q-G VERTICAL MOTION...AND APPROACH OF
UPPER LEVEL SPEED MAX...ENOUGH FACTORS WARRANT AN INCREASE IN POPS
TO LIKELY FOR THE DENVER METRO AND POINTS SOUTH AND EAST THIS
AFTERNOON. WITH STRONG GUSTY NORTHERLY WINDS...WILL ADD AREAS OF
BLOWING SNOW TO THE FORECAST AS WELL EAST/SOUTHEAST OF DENVER. AN
ADVISORY MAY BE NEEDED FOR THOSE LOCATIONS DUE TO COMBINATION OF
GUSTY WINDS AND HIGHER PROBABILITY OF SNOW...WILL CONTINUE TO
MONITOR.
THINGS DRY OUT RATHER QUICKLY FROM NORTH TO SOUTH THIS EVENING
WITH CLEARING SKIES OVERNIGHT. TEMPERATURES WILL BE COLD
ESPECIALLY WHERE WINDS DECREASE SUFFICIENTLY.
LONG TERM...AN UPPER LEVEL RIDGE WILL BE OVER THE AREA ON TUE
WITH DRY WLY FLOW ALOFT. TEMPS WILL MODERATE SOME WITH READINGS
IN THE MID TO UPPER 40S ACROSS NERN CO. FOR WED THE FLOW ALOFT
WILL BECOME MORE SWLY AS AN UPPER LEVEL TROUGH DEVELOPS OVER THE
WRN US. SOME MID AND HIGH LEVEL MOISTURE WILL MOVE ACROSS BUT
OUTSIDE OF SOME CLOUDS IT SHOULD REMAIN DRY. 850-700 TEMPS WOULD
SUPPORT HIGHS IN THE 50S TO NR 60 OVER NERN CO.
FOR THU THE UPPER LEVEL TROUGH WILL INTENSIFY OVER THE WRN US WITH
SWLY FLOW CONTINUING. ONCE AGAIN SOME MID AND HIGH LEVEL MOISTURE
WILL BE EMBEDDED IN THE FLOW HOWEVER OUTSIDE OF A SLIGHT CHC OF
-SHSN WEST OF THE DIVIDE MAINLY IN ZN 31 IT LOOKS DRY. HIGHS WILL
REMAIN MILD ONCE AGAIN OVER NERN CO WITH READINGS IN THE MID 50S
TO LOWER 60S. BY FRI AN UPPER LEVEL STORM SYSTEM WILL DEVELOP OVER
SRN CALIFORNIA WITH SSW FLOW ALOFT. BOTH THE GFS AND ECMWF SHOW AN
INCREASE IN MOISTURE HOWEVER WITH SSW FLOW AT 700 MB BEST SHOT OF
SNOW WILL STAY WEST OF THE DIVIDE. EAST OF THE MTNS A CDFNT WILL
TRY TO BACKDOOR INTO NERN CO DURING THE DAY AS SFC LOW PRES DVLPS
OVER SRN CO. AT THIS TIME WILL DROP HIGHS BACK INTO THE 40S ACROSS
NERN CO. CROSS-SECTIONS REALLY DO NOT SHOW THAT MUCH MOISTURE IN
THE LOWER LEVELS THRU FRI AFTN SO WILL ONLY MENTION A SLIGHT CHC
OF SHOWERS IN AND NR THE FOOTHILLS.
BY THE WEEKEND THERE ARE MAJOR DIFFERENCES BETWEEN THE GFS AND
ECMWF MODELS WITH REGARDS TO HANDLING OF THE UPPER LEVEL STORM
SYSTEM OVER SRN CALIFORNIA. THE GFS SHOWS A SIGNIFICANT PIECE OF
ENERGY LIFTING ENE OUT OF THE MAIN LOW AND TRACKS IT ACROSS NERN
CO BY SAT NIGHT WHILE THE UPPER LEVEL LOW MOVES INTO SRN ARIZONA.
MEANWHILE THE GFS SHOWS A SECONDARY SURGE OF COLDER AIR MOVING
INTO NERN CO FRI NIGHT INTO SAT WITH INCREASING UPSLOPE FLOW AS
THE PIECE OF ENERGY MOVES ACROSS LEADING TO A GOOD CHANCE OF PCPN FRI
NIGHT THRU SAT AFTN ESPECIALLY EAST OF THE DIVIDE ACROSS THE
PLAINS. FCST THICKNESSES SUGGEST MOST OF THE PCPN WOULD FALL AS
SNOW OVER NERN CO WITH SEVERAL INCHES POSSIBLE. BY SAT NIGHT INTO
SUN THE SECOND PIECE OF ENERGY OVER SRN ARIZONA MOVES EAST ACROSS
SRN NEW MEXICO AS MUCH DRIER AIR SPREADS ACROSS NRN CO. THUS THIS
WOULD LEAD TO LITTLE ADDITIONAL PCPN SAT NIGHT THRU SUN.
MEANWHILE THE ECMWF...GEM AND EVEN SEVERAL OF THE GFS ENSEMBLE
MEMBERS SHOW THE UPPER LEVEL LOW OVER SRN CALIFORNIA REMAINING AS
COMPACT SYSTEM AND MOVING ENE INTO SRN COLORADO/NRN NEW MEXICO BY
SAT NIGHT AND THEN INTENSIFYING OVER ERN CO/WRN KANSAS BY SUN
MORNING. BASED ON THIS SOLUTION THE BEST CHC OF PCPN WOULD BE FM
SAT AFTN INTO SUN ACROSS NRN CO WITH STILL SEVERAL INCHES OF SNOW
POSSIBLE HOWEVER IT WOULD BE DELAYED ROUGHLY 18 HOURS VS WHAT THE
OPERATIONAL GFS IS SHOWING. OVERALL THE ECMWF HAS BEEN VERY
CONSISTENT SHOWING THIS STORM SYSTEM AFFECTING NRN CO FOR THE LAST
4 DAYS WHILE THE GFS HAS HAD A PLETHORA OF DIFFERENT SOLUTIONS. AT
THIS POINT SINCE THE TIMING OF THE SYSTEM IS STILL SOMEWHAT
CERTAIN WILL KEEP POPS IN THE CHC CATEGORY FM FRI NIGHT THRU SUN
UNTIL IT BECOMES MORE CLEAR ON WHEN THE BEST CHC OF PCPN WILL
OCCUR.
AVIATION...DIFFICULT FORECAST WITH REGARD TO STRATUS THIS MORNING
AND BETTER CHANCE OF SNOW THIS AFTERNOON. WITH SUFFICIENT BUT VERY
SHALLOW UPSLOPE AND CLOSE T/TD SPREADS EARLY THIS MORNING...WE
WOULD EXPECT A STRATUS DECK NEAR 1000-1500 FT AGL TO DEVELOP IN
THE EARLY MORNING HOURS...BUT QUITE A BIT OF UNCERTAINTY AS KCYS
REPORTED A 300 FOOT CEILING EARLIER ONLY TO HAVE IT
DISSIPATE...AND THEN REFORM AGAIN NEAR 1000 FT AGL. BY 16Z-18Z...
COULD SEE SNOW SHOWERS BEGIN TO DEVELOP IN THE AREA BUT BEST
CHANCE PER LATEST HRRR AND RAP SUGGEST 20Z- 23Z FOR MAIN THREAT.
COULD SEE VSBYS BRIEFLY DROP TO ONE HALF MILE IN A HEAVIER SNOW
SHOWER WITH A QUICK INCH OF SNOW. MOST LIKELY SCENARIO IS FOR A
DUSTING TO LESS THAN 1 INCH...BUT A CHANCE OF 1-2 INCH SNOW
BETWEEN 20Z AND 23Z. BY 00Z-02Z ALL SNOW SHOULD BE OUT OF THE AREA
WITH CLEARING SKIES. NORTH/NORTHEAST WINDS TODAY SHOULD GUST TO
BETWEEN 25 AND 30 KTS...WITH STRONGEST WINDS BEFORE 14Z AND THEN
AGAIN AFTER NEXT FRONTAL PUSH 19Z-21Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY FOR COZ031-033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RPK
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1157 AM CST MON MAR 4 2013
.DISCUSSION...
ISSUED 1058 AM CST MON MAR 4 2013
THOUGH THE MAJORITY OF THE PRECIP IS OVER FOR THIS MORNING...SOME
WEAK WAA AND A COUPLE OF WAVES ON WATER VAPOR SAT IMAGERY MAY
RESULT IN SOME RAIN/SNOW SHOWERS THROUGH THE REMAINDER OF THE DAY.
GOING FORECAST IS ON TRACK FOR TODAY...INCLUDING THE HOURLY
TEMPERATURE TREND. WILL UPDATE THE FORECAST TO ELIMINATE MORNING
WORDING...BUT NO MAJOR CHANGES ARE ANTICIPATED IN THE SHORT TERM.
CLOUDY CONDITIONS AND A WEAK SOUTHERLY COMPONENT TO THE WINDS
SHOULD KEEP THE TEMPS IN THE 30S...AND CREEPING INTO THE LOW TO
MID 40S IN THE SRN HALF OF THE STATE.
&&
.AVIATION...
ISSUED 1149 AM CST MON MAR 4 2013
NOT MUCH OF A SHIFT IN THE MODEL DATA FOR THE PRECIPITATION
BEGINNING IN THE OVERNIGHT TONIGHT AND THROUGH TOMORROW MORNING.
PRECIPITATION TYPE AT THE BEGINNING OF THE EVENT...AFTER MIDNIGHT
AND INTO TOMORROW MORNING WILL BE A BIT OF AN ISSUE...WITH SN AND
PL THE MOST LIKELY TYPES. IN NRN TERMINALS...MORE LIKELY TO BE
SNOW...AND BY SHORTLY AFTER DAWN...SHOULD SEE THE CHANGE OVER TO
ALL SNOW. KEEPING IN THE PREDOMINANT WEATHER...THOUGH THE MORNING
AND PROBABLY THROUGHOUT THE DAY...THOUGH THE INTENSITY OF THE
SNOWFALL WILL LIKELY RESULT IN A CHANGE IN THE VISIBILITY FROM
TIME TO TIME. ESSENTIALLY...VFR THROUGH THE AFTERNOON AND INTO THE
EVENING WITH SOUTHEASTERLY WINDS AND GUSTS THROUGH THE AFTERNOON
TO 25KTS. AFTER MIDNIGHT...CONDITIONS WILL DETERIORATE AND STAY DOWN
THROUGH TOMORROW...IFR THROUGH THE PRECIPITATION AT BEST.
HJS
&&
.PREV DISCUSSION...
ISSUED 315 AM CST MON MAR 4 2013
TIGHT THERMAL GRADIENT MOVING INTO FAR WESTERN ILLINOIS EARLY THIS
MORNING...WITH 850 MB TEMPERATURES RISING ABOUT 6 DEGREES CELSIUS
IN ABOUT A 60 MILE SPAN. ISENTROPIC LIFT ASSOCIATED WITH THIS
GRADIENT HAS PRODUCED SOME LIGHT FREEZING RAIN AND SNOW OVER
IOWA...WITH LIGHT SNOW AND SLEET ACROSS WESTERN ILLINOIS JUST EAST
OF THE MISSISSIPPI RIVER. UPPER LOW DROPPING SOUTHEAST ACROSS
MONTANA IS PART OF THE MAIN SHOW THAT WILL BE AFFECTING OUR
WEATHER THE NEXT COUPLE DAYS...ALONG WITH A SURFACE LOW CURRENTLY
ANALYZED OVER WESTERN OKLAHOMA.
PRIMARY FORECAST CONCERN IN THE SHORT TERM INVOLVES PRECIPITATION
TYPES AND AMOUNTS THROUGH TUESDAY NIGHT. IN THE LONGER TERM...
FOCUS SHIFTS TOWARD A WARMER STORM SYSTEM THAT ARRIVES SOMETIME
NEXT WEEKEND.
SHORT TERM...TODAY THROUGH WEDNESDAY...
STRONGEST LIFT WITH THE CURRENT PRECIPITATION SHOULD LAST THROUGH
ABOUT MID MORNING...AND MOST OF THE MODELS HAVE BEEN WEAKENING
THIS PRECIPITATION WITH TIME. HIGHEST POPS EXPECTED TO BE EARLY
MORNING IN THE NORTHWEST CWA...WITH THE NAM...ECMWF AND RAP MODELS
ALL SUGGESTING MAINLY DRY CONDITIONS THE REMAINDER OF THE DAY.
SURFACE LOW PROGGED TO MOVE INTO WESTERN KENTUCKY AFTER
MIDNIGHT...WITH THE UPPER LOW DROPPING SOUTHEAST INTO CENTRAL
ILLINOIS BY LATE TUESDAY AFTERNOON. PRECIP DEVELOPMENT SHOULD
BEGIN IN EARNEST BY MID TO LATE THIS EVENING AND EXPAND
OVERNIGHT...AS INVERTED SURFACE TROUGH ASSOCIATED WITH THE LOW TO
OUR SOUTH SWINGS THROUGH THE AREA. HAVE SOME CONCERNS WITH PRECIP
TYPES OVERNIGHT AND EARLY TUESDAY...AS NAM AND GFS SOUNDINGS
SHOWING SOME DECENT WARMING IN THE LOWER LAYERS AFTER MIDNIGHT AND
SOME OF THE PRECIP MAY BE RAIN FOR A TIME AS FAR NORTH AS PEORIA.
WITH THE TREND TOWARD SOME WARMER CONDITIONS FOR A TIME... HAVE
HELD OFF ON ANY WINTER HEADLINES AS THE AMOUNT OF SNOW REMAINS IN
FLUX...BUT STILL LOOKS LIKE THE AREAS NORTH OF I-74 ARE MOST LIKELY
TO GET A FEW INCHES OR MORE OF ACCUMULATION THROUGH TUESDAY NIGHT.
MORE OF A TREND TOWARD SNOW IS EXPECTED ON TUESDAY AS THE SURFACE
LOW MOVES UP THE OHIO VALLEY. THE SOUTHEAST CWA IS EXPECTED TO
REMAIN RAIN A GOOD PORTION OF THE TIME...WITH A CHANGEOVER TO SNOW
LATE TUESDAY AFTERNOON. SNOW IS EXPECTED TO LINGER MOST OF THE
EVENING OVER THE ENTIRE AREA AS THE UPPER LOW PASSES...THEN
DIMINISH AFTER MIDNIGHT WITH THE LOW EXITING THE AREA.
LONG TERM...THURSDAY THROUGH SUNDAY...
A MUCH WARMER PATTERN IS STILL ON TAP FOR LATE WEEK...AS AN UPPER
LOW DIGS ALONG THE CALIFORNIA COAST AND PROVIDES A SOUTHWEST FLOW
INTO THE MIDWEST. MAIN FOCUS WILL BE WITH THE EVOLUTION OF THIS
LOW DURING THE WEEKEND...AND HOW THE BRANCHES OF THE JET STREAM
PHASE OVER THE CENTER OF THE COUNTRY. THE GFS MODEL CUTS THE LOW
OFF OVER THE DESERT SOUTHWEST AND PROVIDES MUCH MORE PHASING...
AND THUS A WETTER PATTERN LATER IN THE WEEKEND. MEANWHILE... THE
ECMWF IS MUCH SLOWER WITH LIFTING THE LOW NORTHEAST AND FORMING A
LARGE OCCLUDED SYSTEM OVER THE MID SECTION OF THE NATION...WHICH
WOULD HOLD OFF MUCH OF THE RAIN THREAT UNTIL LATER ON SUNDAY. WILL
GO WITH LOW POPS OF 20-30 PERCENT DURING THE WEEKEND FOR NOW...
HIGHEST IN THE WEST...BUT CONFIDENCE IS LOW DUE TO THE LARGE MODEL
DISCREPANCIES.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1117 AM CST MON MAR 4 2013
.DISCUSSION...
ISSUED 1058 AM CST MON MAR 4 2013
THOUGH THE MAJORITY OF THE PRECIP IS OVER FOR THIS MORNING...SOME
WEAK WAA AND A COUPLE OF WAVES ON WATER VAPOR SAT IMAGERY MAY
RESULT IN SOME RAIN/SNOW SHOWERS THROUGH THE REMAINDER OF THE DAY.
GOING FORECAST IS ON TRACK FOR TODAY...INCLUDING THE HOURLY
TEMPERATURE TREND. WILL UPDATE THE FORECAST TO ELIMINATE MORNING
WORDING...BUT NO MAJOR CHANGES ARE ANTICIPATED IN THE SHORT TERM.
CLOUDY CONDITIONS AND A WEAK SOUTHERLY COMPONENT TO THE WINDS
SHOULD KEEP THE TEMPS IN THE 30S...AND CREEPING INTO THE LOW TO
MID 40S IN THE SRN HALF OF THE STATE.
HJS
&&
.AVIATION...
ISSUED 551 AM CST MON MAR 4 2013
A WINTER STORM WILL APPROACH THE CENTRAL ILLINOIS TERMINALS DURING
THE 12Z TAF VALID TIME. A BAND OF MAINLY LIGHT SNOW WILL CROSS THE
AREA THIS MORNING...CAUSING A BRIEF REDUCTION TO MVFR OR IFR
CONDITIONS. WHILE ADDITIONAL PRECIPITATION IS POSSIBLE DURING THE
PERIOD...THE COVERAGE SHOULD BE QUITE LOW UNTIL VERY LATE TONIGHT.
THEN...A STEADIER SNOW WILL BEGIN TO SPREAD FROM WEST TO EAST
TOWARD DAYBREAK TUESDAY. THE MORE WIDESPREAD SNOW SHOULD BE
ACCOMPANIED BY IFR CONDITIONS.
PREDOMINANTLY SOUTHEAST WINDS ARE EXPECTED THROUGH THE PERIOD
AHEAD OF THE APPROACHING STORM. THE WINDS WILL GUST OVER 20 KTS AT
TIMES DURING THE DAYLIGHT HOURS TODAY.
BAK
&&
.PREV DISCUSSION...
ISSUED 315 AM CST MON MAR 4 2013
TIGHT THERMAL GRADIENT MOVING INTO FAR WESTERN ILLINOIS EARLY THIS
MORNING...WITH 850 MB TEMPERATURES RISING ABOUT 6 DEGREES CELSIUS
IN ABOUT A 60 MILE SPAN. ISENTROPIC LIFT ASSOCIATED WITH THIS
GRADIENT HAS PRODUCED SOME LIGHT FREEZING RAIN AND SNOW OVER
IOWA...WITH LIGHT SNOW AND SLEET ACROSS WESTERN ILLINOIS JUST EAST
OF THE MISSISSIPPI RIVER. UPPER LOW DROPPING SOUTHEAST ACROSS
MONTANA IS PART OF THE MAIN SHOW THAT WILL BE AFFECTING OUR
WEATHER THE NEXT COUPLE DAYS...ALONG WITH A SURFACE LOW CURRENTLY
ANALYZED OVER WESTERN OKLAHOMA.
PRIMARY FORECAST CONCERN IN THE SHORT TERM INVOLVES PRECIPITATION
TYPES AND AMOUNTS THROUGH TUESDAY NIGHT. IN THE LONGER TERM...
FOCUS SHIFTS TOWARD A WARMER STORM SYSTEM THAT ARRIVES SOMETIME
NEXT WEEKEND.
SHORT TERM...TODAY THROUGH WEDNESDAY...
STRONGEST LIFT WITH THE CURRENT PRECIPITATION SHOULD LAST THROUGH
ABOUT MID MORNING...AND MOST OF THE MODELS HAVE BEEN WEAKENING
THIS PRECIPITATION WITH TIME. HIGHEST POPS EXPECTED TO BE EARLY
MORNING IN THE NORTHWEST CWA...WITH THE NAM...ECMWF AND RAP MODELS
ALL SUGGESTING MAINLY DRY CONDITIONS THE REMAINDER OF THE DAY.
SURFACE LOW PROGGED TO MOVE INTO WESTERN KENTUCKY AFTER
MIDNIGHT...WITH THE UPPER LOW DROPPING SOUTHEAST INTO CENTRAL
ILLINOIS BY LATE TUESDAY AFTERNOON. PRECIP DEVELOPMENT SHOULD
BEGIN IN EARNEST BY MID TO LATE THIS EVENING AND EXPAND
OVERNIGHT...AS INVERTED SURFACE TROUGH ASSOCIATED WITH THE LOW TO
OUR SOUTH SWINGS THROUGH THE AREA. HAVE SOME CONCERNS WITH PRECIP
TYPES OVERNIGHT AND EARLY TUESDAY...AS NAM AND GFS SOUNDINGS
SHOWING SOME DECENT WARMING IN THE LOWER LAYERS AFTER MIDNIGHT AND
SOME OF THE PRECIP MAY BE RAIN FOR A TIME AS FAR NORTH AS PEORIA.
WITH THE TREND TOWARD SOME WARMER CONDITIONS FOR A TIME... HAVE
HELD OFF ON ANY WINTER HEADLINES AS THE AMOUNT OF SNOW REMAINS IN
FLUX...BUT STILL LOOKS LIKE THE AREAS NORTH OF I-74 ARE MOST LIKELY
TO GET A FEW INCHES OR MORE OF ACCUMULATION THROUGH TUESDAY NIGHT.
MORE OF A TREND TOWARD SNOW IS EXPECTED ON TUESDAY AS THE SURFACE
LOW MOVES UP THE OHIO VALLEY. THE SOUTHEAST CWA IS EXPECTED TO
REMAIN RAIN A GOOD PORTION OF THE TIME...WITH A CHANGEOVER TO SNOW
LATE TUESDAY AFTERNOON. SNOW IS EXPECTED TO LINGER MOST OF THE
EVENING OVER THE ENTIRE AREA AS THE UPPER LOW PASSES...THEN
DIMINISH AFTER MIDNIGHT WITH THE LOW EXITING THE AREA.
LONG TERM...THURSDAY THROUGH SUNDAY...
A MUCH WARMER PATTERN IS STILL ON TAP FOR LATE WEEK...AS AN UPPER
LOW DIGS ALONG THE CALIFORNIA COAST AND PROVIDES A SOUTHWEST FLOW
INTO THE MIDWEST. MAIN FOCUS WILL BE WITH THE EVOLUTION OF THIS
LOW DURING THE WEEKEND...AND HOW THE BRANCHES OF THE JET STREAM
PHASE OVER THE CENTER OF THE COUNTRY. THE GFS MODEL CUTS THE LOW
OFF OVER THE DESERT SOUTHWEST AND PROVIDES MUCH MORE PHASING...
AND THUS A WETTER PATTERN LATER IN THE WEEKEND. MEANWHILE... THE
ECMWF IS MUCH SLOWER WITH LIFTING THE LOW NORTHEAST AND FORMING A
LARGE OCCLUDED SYSTEM OVER THE MID SECTION OF THE NATION...WHICH
WOULD HOLD OFF MUCH OF THE RAIN THREAT UNTIL LATER ON SUNDAY. WILL
GO WITH LOW POPS OF 20-30 PERCENT DURING THE WEEKEND FOR NOW...
HIGHEST IN THE WEST...BUT CONFIDENCE IS LOW DUE TO THE LARGE MODEL
DISCREPANCIES.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
325 PM CST MON MAR 4 2013
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 254 PM CST MON MAR 4 2013
WATER VAPOR AND HOURLY RAP ANALYSES SHOW A FAIRLY COMPACT JET STREAK
MOVING SOUTHEAST FROM IDAHO INTO COLORADO. THIS JET STREAK WAS WELL
TO THE SOUTHWEST OF THE MAIN UPPER LOW CENTER WHICH WAS CENTERED
ALONG THE WESTERN SOUTH DAKOTA-NORTH DAKOTA BORDER. THE FIRST
FRONTAL PASSAGE OCCURRED EARLIER IN THE DAY, BUT THE AIRMASS BEHIND
THIS FRONT WAS MAINLY DOWNSLOPE MODIFIED CONTINENTAL POLAR AIR...AND
NOT ARCTIC IN NATURE AT ALL. BECAUSE OF THIS...INSOLATION AND
CONTINUED DOWNSLOPE MODIFICATION YIELDED AFTERNOON TEMPERATURES
QUITE MILD AND RIGHT AROUND THE SEASONAL AVERAGE FOR EARLY MARCH.
THE EXCEPTION OF THIS WAS ACROSS SOUTH CENTRAL KANSAS WHERE
LINGERING SNOWPACK CONTINUED GENERALLY FROM HAYS TO KINSLEY TO
COLDWATER AND POINTS EAST (ESPECIALLY PRATT AND BARBER COUNTIES).
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST MON MAR 4 2013
LOWER-MID LEVEL CLOUD WILL CONTINUE TO INCREASE LATE THIS AFTERNOON
AND EVENING AS UPWARD VERTICAL MOTION INCREASES AHEAD OF THE
APPROACHING JET STREAK. RADAR ECHOES CONTINUED TO INCREASE ACROSS
NORTHEASTERN COLORADO AND AS THE UPPER JET STREAK APPROACHES WESTERN
KANSAS...FRONTOGENESIS IN THE MID TROPOSPHERE WILL FURTHER
INCREASE...AND RAIN/SNOW SHOWERS WILL INCREASE IN COVERAGE. POPS
WERE INCREASED TO THE 30-40 PERCENT ACROSS FAR WEST CENTRAL
KANSAS...AND THE CHALLENGE OF PRECIPITATION TYPE IS PRETTY HIGH
GIVEN THE RAPID COOLING OF THE 900-800MB LAYER EARLY THIS EVENING AS
THE SECOND COLD FRONT MOVES THROUGH AND EVAPORATIVE COOLING ENSUES.
THE INCREASING RADAR TRENDS ACROSS NORTHWEST KANSAS WOULD SUGGEST AN
INCREASE IN POPS ACROSS THE BOARD...SO BY PRESS TIME BEFORE 21Z WILL
HAVE POPS INCREASED AND SLIGHTLY HIGHER QPF AMOUNTS. THE PERIOD FROM
ROUGHLY 00Z TO 06Z WILL BE THE BEST TIME FRAME FOR LIGHT
ACCUMULATING PRECIPITATION AS THE 700MB FRONTOGENETIC MOVES QUICKLY
SOUTHEAST ACROSS WESTERN KANSAS. WILL BEGIN A RAPID CLEARING TREND
IN THE GRIDS TOWARD DAYBREAK TUESDAY. WE WILL REMAIN IN A FAIRLY
STRONG 850-700MB GRADIENT THROUGH MOST OF THE DAY TUESDAY WHICH WILL
KEEP WINDS UP IN THE BREEZY TO WINDY CATEGORY...BUT REMAINING BELOW
WIND ADVISORY CRITERIA AS IT LOOKS RIGHT NOW. HIGH TEMPERATURE
FORECAST WILL NOT BE CHANGED FROM THE GOING FORECAST WITH WIDESPREAD
LOWER TO MID 40S EXPECTED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CST MON MAR 4 2013
GOOD POTENTIAL EXISTS FOR COLDER TEMPERATURES OVERNIGHT TUESDAY
INTO EARLY WEDNESDAY MORNING. THE CENTER OF THE HIGH PRESSURE
SURFACE RIDGE AXIS WILL LIKELY BE CENTERED ACROSS CENTRAL KANSAS FOR
SEVERAL HOURS TUESDAY NIGHT. THIS WILL ALSO BE UNDER A VERY DRY DEEP
ATMOSPHERIC COLUMN, PROMOTING LONGWAVE RADIATIONAL COOLING.
SURFACE WINDS WILL QUICKLY TURN SOUTHEASTERLY ON THE WEST SIDE OF
THE RIDGE EARLY WEDNESDAY MORNING, AND EVEN BEFORE THAT ACROSS FAR
WESTERN KANSAS. THE MESOSCALE NAM INDICATES A POCKET OF THE COLDEST
POSSIBLE TEMPERATURES OF ALL MODEL OUTPUT AND MOS GUIDANCE. HOWEVER
IT APPEARS TO BE HAVING PROBLEMS ACCOUNTING FOR LEFTOVER SURFACE
SNOWDEPTH. THE ECMWF MOS APPEARS A GENERALLY REASONABLE BETTER
COMPROMISE IN THIS INSTANCE, AND WAS CLOSELY FOLLOWED WEDNESDAY
MORNING.
WEDNESDAY AFTERNOON WILL BRING WARMER TEMPERATURES, ESPECIALLY ACROSS
WESTERN KANSAS. THE NAM MODEL INDICATES A SHARP 850 MB LEVEL
TEMPERATURE GRADIENT ACROSS FROM AROUND DODGE CITY TO THE COLORADO
LINE, WITH SOUTHERLY SURFACE WINDS AROUND A DEVELOPING LEE SURFACE
LOW. EVEN WARMER BOUNDARY LAYER AIR WILL BE PRESENT EARLY BY
THURSDAY AFTERNOON. BY THURSDAY THE AXIS OF THE MID LEVEL THERMAL
RIDGE BECOMES CENTERED OVER THE HIGH PLAINS, AND THE SURFACE TROUGH
PULLS SLIGHTLY FARTHER EASTWARD, DRAWING IN WARMER AIR FROM THE
HIGHER TERRAIN OF SE COLORADO AND NE NEW MEXICO. WARMER OVERNIGHT
LOWS WILL BE EXPERIENCED AS WELL AS PERSISTENT SOUTHERLY WINDS
DURING THE OVERNIGHTS IN SLIGHTLY HIGHER THETA-E AIR. MELTING SNOW
IS LIKELY TO RE-FREEZE IN MOST CASES, AND IT IS NOT OBVIOUS AT THIS
POINT OF ANY NIGHTS APPEARING OVERLY PRONE TO DENSE FOG DEVELOPMENT.
A BETTER CHANCE FOR DENSE FOG WILL COME CLOSER TO THE BEGINNING OF
THE DYNAMIC LOW EXPECTED THIS WEEKEND STARTING AROUND FRIDAY.
LARGE UNCERTAINTY EXISTS WITH RESPECT TO THE STORM SYSTEM EXPECTED TO
INTENSIFY ACROSS THE CENTRAL HIGH PLAINS REGION BETWEEN FRIDAY AND
SUNDAY. THE ECMWF AND CANADIAN (GEM) MODELS ARE IN GENERALLY CLOSER
AGREEMENT TO ONE ANOTHER WITH A MORE BAROCLINIC SYSTEM, AS WELL AS
CONSIDERABLY SLOWER THAN THE GFS MODEL (BY AROUND 12 HOURS). THE
RECENT MODEL CONSENSUS, BLENDED WITH THE LAST FORECAST DOES LOWER
PROBABILITIES ON FRIDAY AND FRIDAY NIGHT, AND FOCUSES THE HIGHER
(LIKELY) CHANCES SATURDAY INTO SUNDAY. TEMPERATURES WILL ALSO BE A
CHALLENGE DURING THIS PERIOD. THE TRACK AND NATURE OF THE DYNAMIC
LOW WILL MAKE A LARGE DIFFERENCE, WITH A HIGH TEMPERATURE ENSEMBLE
SPREAD SATURDAY FROM THE LOW 40S TO LOW 60S. BETTER MODEL AGREEMENT
WILL BE LOOKED FOR AS THE SYSTEM BECOMES BETTER SAMPLED LATER IN THE
WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1154 AM CST MON MAR 4 2013
AS A FAIRLY INTENSE STORM SYSTEM TRACKS SOUTHEAST ACROSS THE
NORTHERN PLAINS TODAY AND TONIGHT...WINDS WILL STAY FAIRLY STRONG
FROM THE NORTH THROUGH THIS AFTERNOON AND TONIGHT. A SECONDARY COLD
FRONTAL SURGE WILL CAUSE A SLIGHT SHIFT IN THE WIND FROM
NORTH-NORTHEAST TO NORTH OR NORTH-NORTHWEST AND A SLIGHT INCREASE TO
24-26 KNOTS (GUSTING TO 31 TO 34 KNOTS). SOME LIGHT RAIN OR SNOW
SHOWERS WILL BE POSSIBLE THROUGH THE EARLY TO MID EVENING
HOURS...HOWEVER THE SHOWERS ARE EXPECTED TO BE LIGHT IN NATURE AND
LAST NO LONGER THAN AN HOUR OR TWO. THE IMPACTS AT THE TERMINALS
WILL BE MINIMAL AND WILL NOT EVEN INCLUDE THEM IN THE TAFS. CEILING
IS NOT EXPECTED TO FALL BELOW 3 OR 4 THOUSAND FEET EXCEPT AT
GCK...WHERE MVFR CEILINGS WILL BE FORECAST FROM MID TO LATE EVENING.
SKY CLEAR CONDITIONS WILL BE EXPECTED AFTER THE STORM PASSES TO THE
NORTHEAST TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 42 17 52 / 20 0 0 0
GCK 20 44 16 54 / 40 0 0 0
EHA 22 48 24 61 / 30 10 0 0
LBL 20 47 19 54 / 20 10 0 0
HYS 22 40 14 46 / 20 10 0 0
P28 25 43 16 49 / 20 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
256 PM CST MON MAR 4 2013
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 254 PM CST MON MAR 4 2013
WATER VAPOR AND HOURLY RAP ANALYSES SHOW A FAIRLY COMPACT JET STREAK
MOVING SOUTHEAST FROM IDAHO INTO COLORADO. THIS JET STREAK WAS WELL
TO THE SOUTHWEST OF THE MAIN UPPER LOW CENTER WHICH WAS CENTERED
ALONG THE WESTERN SOUTH DAKOTA-NORTH DAKOTA BORDER. THE FIRST
FRONTAL PASSAGE OCCURRED EARLIER IN THE DAY, BUT THE AIRMASS BEHIND
THIS FRONT WAS MAINLY DOWNSLOPE MODIFIED CONTINENTAL POLAR AIR...AND
NOT ARCTIC IN NATURE AT ALL. BECAUSE OF THIS...INSOLATION AND
CONTINUED DOWNSLOPE MODIFICATION YIELDED AFTERNOON TEMPERATURES
QUITE MILD AND RIGHT AROUND THE SEASONAL AVERAGE FOR EARLY MARCH.
THE EXCEPTION OF THIS WAS ACROSS SOUTH CENTRAL KANSAS WHERE
LINGERING SNOWPACK CONTINUED GENERALLY FROM HAYS TO KINSLEY TO
COLDWATER AND POINTS EAST (ESPECIALLY PRATT AND BARBER COUNTIES).
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST MON MAR 4 2013
LOWER-MID LEVEL CLOUD WILL CONTINUE TO INCREASE LATE THIS AFTERNOON
AND EVENING AS UPWARD VERTICAL MOTION INCREASES AHEAD OF THE
APPROACHING JET STREAK. RADAR ECHOES CONTINUED TO INCREASE ACROSS
NORTHEASTERN COLORADO AND AS THE UPPER JET STREAK APPROACHES WESTERN
KANSAS...FRONTOGENESIS IN THE MID TROPOSPHERE WILL FURTHER
INCREASE...AND RAIN/SNOW SHOWERS WILL INCREASE IN COVERAGE. POPS
WERE INCREASED TO THE 30-40 PERCENT ACROSS FAR WEST CENTRAL
KANSAS...AND THE CHALLENGE OF PRECIPITATION TYPE IS PRETTY HIGH
GIVEN THE RAPID COOLING OF THE 900-800MB LAYER EARLY THIS EVENING AS
THE SECOND COLD FRONT MOVES THROUGH AND EVAPORATIVE COOLING ENSUES.
THE INCREASING RADAR TRENDS ACROSS NORTHWEST KANSAS WOULD SUGGEST AN
INCREASE IN POPS ACROSS THE BOARD...SO BY PRESS TIME BEFORE 21Z WILL
HAVE POPS INCREASED AND SLIGHTLY HIGHER QPF AMOUNTS. THE PERIOD FROM
ROUGHLY 00Z TO 06Z WILL BE THE BEST TIME FRAME FOR LIGHT
ACCUMULATING PRECIPITATION AS THE 700MB FRONTOGENETIC MOVES QUICKLY
SOUTHEAST ACROSS WESTERN KANSAS. WILL BEGIN A RAPID CLEARING TREND
IN THE GRIDS TOWARD DAYBREAK TUESDAY. WE WILL REMAIN IN A FAIRLY
STRONG 850-700MB GRADIENT THROUGH MOST OF THE DAY TUESDAY WHICH WILL
KEEP WINDS UP IN THE BREEZY TO WINDY CATEGORY...BUT REMAINING BELOW
WIND ADVISORY CRITERIA AS IT LOOKS RIGHT NOW. HIGH TEMPERATURE
FORECAST WILL NOT BE CHANGED FROM THE GOING FORECAST WITH WIDESPREAD
LOWER TO MID 40S EXPECTED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 232 AM CST MON MAR 4 2013
STARTING WITH TUESDAY, A COLD FRONT WILL HAVE WENT THROUGH WESTERN
KANSAS LATE TODAY (MONDAY), AND COLD HIGH PRESSURE AT THE SURFACE
WILL WEDGE A NOSE OF COLDER AIR SOUTHWARD. IN THE UPPER ATMOSPHERE,
A LARGE TROUGH OF LOW PRESSURE WILL SWING FROM NORTHWEST TO EAST
THROUGH KANSAS. THIS WILL CERTAINLY BRING MID AND HIGH LEVEL
MOISTURE, AND A LITTLE MOISTURE MAY BE SQUEEZED OUT VERY EARLY
TUESDAY. HOWEVER, THE SUPPRESSION FROM THE UPPER HIGH PRESSURE WILL
LIKELY OVERPOWER ANY DEVELOPMENT OF LIGHT PRECIP, AND THUS
PRECIPITATION CHANCES WILL BE NIL TUE. MAXIMUM TEMPERATURES IN THE
HAYS AREAS DOWN TO THE GREENSBURG AREAS WILL BARELY REACH 40F ON
TUESDAY, WITH HIGHS IN THE UPPER 40S DOWN NEAR ELKHART AND JOHNSON
CITY. AN UPPER LEVEL RIDGE WILL BUILD IN FROM THE WEST WEDNESDAY
AND THURSDAY, BRINGING WARMER MAXIMUM TEMPERATURES IN BY THURSDAY.
MAXIMUM TEMPERATURES THURSDAY WILL RANGE FROM THE MID TO UPPER 50S
EAST OF HIGHWAY 183, TO AS HIGH AS THE LOWER 70S ALONG THE COLORADO
BORDER. THE UPPER FLOW WILL TURN SOUTHWEST FRIDAY, AS A LARGE UPPER
LEVEL LOW MOVES INTO SOUTHERN CALIFORNIA. PRECIPITATION WILL ALSO
BE HEADING TOWARD KANSAS ON SATURDAY, BUT I DO NOT THINK ANY
CONVECTION WILL MAKE IT INTO WESTERN KANSAS PRIOR TO SATURDAY NIGHT.
FROM SATURDAY NIGHT INTO SUNDAY NIGHT, THAT UPPER LOW WILL BE MOVING
FROM NORTHERN ARIZONA EAST-NORTHEAST THROUGH KANSAS. AS THE LOW
APPROACHES WESTERN KANSAS, DEEPER AND DEEPER MOISTURE WILL EVOLVE.
SHOWERS AND THUNDERSTORMS ARE LIKELY OVER MUCH OF THE WESTERN PLAINS
FROM SATURDAY NIGHT INTO SUNDAY NIGHT. THIS COULD BE THE FIRST
LIQUID CONVECTION OF THE YEAR. RIGHT NOW, IT IS TOO EARLY TO
DETERMINE IF ANY STORMS WILL BE SEVERE OR NOT. ALL MODELS EXCEPT
THE GFS MODEL ARE PAINTING FROM 0.20 TO 0.60 INCH OF PRECIP FOR
SOUTHWEST KANSAS. THIS WILL BE VERY WELCOMED MOISTURE FOR MOST OF
THE SOUTHWEST KANSANS, AS THE 2 1/2 YEAR OLD DROUGHT IS ONGOING. BY
SATURDAY NIGHT, SOME COLD AIR WILL MIX DOWN INTO THE LOWER LAYERS,
AND THE ECMWF 1000-850 THICKNESS FIELDS DROP TO BELOW 1320DM IN THE
WEST AND NORTHWEST SECTIONS OF OUR FORECAST AREA. SO, I PLACE A
PRECIP TYPE OF RAIN OR SNOW NORTH AND WEST OF A LINE FROM HAYS TO
JOHNSON CITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1154 AM CST MON MAR 4 2013
AS A FAIRLY INTENSE STORM SYSTEM TRACKS SOUTHEAST ACROSS THE
NORTHERN PLAINS TODAY AND TONIGHT...WINDS WILL STAY FAIRLY STRONG
FROM THE NORTH THROUGH THIS AFTERNOON AND TONIGHT. A SECONDARY COLD
FRONTAL SURGE WILL CAUSE A SLIGHT SHIFT IN THE WIND FROM
NORTH-NORTHEAST TO NORTH OR NORTH-NORTHWEST AND A SLIGHT INCREASE TO
24-26 KNOTS (GUSTING TO 31 TO 34 KNOTS). SOME LIGHT RAIN OR SNOW
SHOWERS WILL BE POSSIBLE THROUGH THE EARLY TO MID EVENING
HOURS...HOWEVER THE SHOWERS ARE EXPECTED TO BE LIGHT IN NATURE AND
LAST NO LONGER THAN AN HOUR OR TWO. THE IMPACTS AT THE TERMINALS
WILL BE MINIMAL AND WILL NOT EVEN INCLUDE THEM IN THE TAFS. CEILING
IS NOT EXPECTED TO FALL BELOW 3 OR 4 THOUSAND FEET EXCEPT AT
GCK...WHERE MVFR CEILINGS WILL BE FORECAST FROM MID TO LATE EVENING.
SKY CLEAR CONDITIONS WILL BE EXPECTED AFTER THE STORM PASSES TO THE
NORTHEAST TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 42 17 52 / 20 0 0 0
GCK 20 44 16 54 / 20 0 0 0
EHA 22 48 24 61 / 30 10 0 0
LBL 20 47 19 54 / 20 10 0 0
HYS 22 40 14 46 / 10 10 0 0
P28 25 43 16 49 / 20 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...BURKE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 PM EST MON MAR 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 356 PM EST MON MAR 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER THE
WRN DAKOTAS AND A DOWNSTREAM RIDGE OVER THE WRN GREAT LAKES. AT THE
SFC...A RIDGE EXTENDED FROM NRN MANITOBA AND NW ONTARIO INTO UPPER
MI BRINGING EASTERLY WINDS AND MAINLY CLEAR SKIES. CLOUDS ASSOCIATED
WITH THE BROAD AREA OF ISENTROPIC LIFT AHEAD OF THE SFC LOW VOER S
CNTRL N DAKOTA HAD SPREAD INTO FAR WRN UPPER MI WITH MAINLY ONLY
HIGH CLOUDS TO THE EAST.
MODELS WERE CONSISTENT IN TAKING THE DAKOTAS MID LEVEL LOW TO THE SE
TOWARD THE OH VALLEY BY TUE EVENING WITH BEST Q-VECT CONV AND
WAA/ISENTROPIC LIFT STAYING SE OF UPPER MI CLOSER TO THE TRACK OF
THE LOW AND ASSOC INVERTED SFC TROUGH. SO...MUCH OF THE CWA SHOULD
SEE LITTLE OR NO SYNOPTIC SCALE PCPN. CHANCE POPS STILL WERE
RETAINED OVER THE WEST WITH LITTLE IF ANY SNOW ACCUMULATION EXPECTED.
HOWEVER...HIGHER RES MODELS SUGGEST THAT AS NE FLOW STRENGTHENS AND
BECOMES MORE CYCLONIC PULLING 925-800 MB MOISTURE NE OF LAKE
SUPERIOR BACK INTO THE AREA...THE POTENTIAL FOR LAKE ENHANCED SNOW
INTO N CNTRL UPPER MI WILL INCREASE. WITH TEMPS NEAR THE 900 MB
INVERSION HEIGHT (NEAR 3K FT) ONLY AROUND -12C...BOTH INSTABILITY
AND SLR VALUES WILL BE MARGINAL FOR SIGNFICANT SNOW.
HOWEVER...UPSLOPE FLOW INTO THE HIGHER TERRAIN SHOULD BE ENOUGH TO
SUPPORT -SHSN BY TUE AFTERNOON WITH ACCUMULATIONS LESS THAN A HALF
INCH.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 356 PM EST MON MAR 4 2013
THE GENERALLY QUIET MARCH WEATHER CONTINUES THROUGH MUCH OF THE
LONG TERM PERIOD.
EXPECT SOME SNOW SHOWERS TO BE AFFECTING THE AREA
TUESDAY NIGHT INTO WEDNESDAY AS A LINGERING SURFACE TROUGH IS LEFT
BEHIND THE CLIPPER SYSTEM SLIDING TO THE SOUTH OF THE AREA TODAY
THROUGH TUESDAY. ALTHOUGH THE SYSTEM WILL BE TO THE SOUTH OF THE
AREA...DEEPER MOISTURE ROTATING WEST FROM THE LOW NEAR THE NEW
ENGLAND STATES WILL PROVIDE ENOUGH MOISTURE FOR SNOW TO DEVELOP
TUESDAY AFTERNOON INTO TUESDAY NIGHT. H850 TEMPERATURES OF -11C OVER
THE WEST AND -8C OVER THE EAST SHOULD BE COLD ENOUGH FOR LAKE
ENHANCEMENT...ESPECIALLY WITH THE ABUNDANT MOISTURE. IN
ADDITION...WITH THE LINGERING SURFACE TROUGH SLOWLY SLIDING ACROSS
THE AREA AND THE LEFTOVER NORTHERN STREAM SHORTWAVE AND ASSOCIATED
HEIGHT FALLS MOVING EAST ACROSS THE NORTHERN HALF OF THE
CWA...EXPECT A PERIOD OF LIGHT SNOW SHOWERS FOR THE WEST/CENTRAL
UPPER MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. CYCLONIC
NORTH-NORTHEAST SFC-925 WINDS WOULD FAVOR THE NORTHWEST HALF OF
UPPER MICHIGAN FOR THE POPS. DID BUMP POPS UP SOME OVER THE
KEWEENAW FOR LATE TUESDAY NIGHT INTO WEDNESDAY MORNING...AS THERE
IS ADDITIONAL FORCING ALOFT FROM THE SHORTWAVE. SNOW RATIOS LOOK TO
BE ON THE LOW SIDE FOR MOST OF THE AREA...AT OR BELOW 10-1...SINCE
THE CLOUDS STRUGGLE TO GET ABOVE -10C. THERE IS A POTENTIAL FOR
SLIGHTLY HIGHER RATIOS OVER THE KEWEENAW DUE TO THE SYNOPTIC
FORCING...TOWARDS 15-1...BUT BEST FORCING LOOKS TO BE ABOVE THE DGZ
IN THAT AREA TO KEEP RATIOS FROM GETTING TOO HIGH. THE TROUGH
SLIDING EAST ON WEDNESDAY WILL TRANSITION THE LINGERING CLOUDS/SNOW
TO THE NORTHWEST WIND FAVORED LOCATIONS. MOST LOCATIONS WILL SEE A
LIGHT DUSTING OF SNOW BY WEDNESDAY EVENING...BUT SLIGHTLY HIGHER
AMOUNTS OF 1-2 INCHES ARE POSSIBLE OVER THE KEWEENAW AND THE HIGHER
TERRAIN OF MARQUETTE COUNTY.
THIS LINGERING TROUGH AND SHORTWAVE WILL SLIDE TO THE EAST OF THE
AREA ON WEDNESDAY...AS HIGH PRESSURE SLIDES EAST AND OVER THE UPPER
GREAT LAKES FOR WEDNESDAY NIGHT INTO THURSDAY BEFORE PUSHING EAST
ON FRIDAY. THIS HIGH SHOULD LEAD TO GRADUALLY DECREASING CLOUDS
DURING THAT PERIOD. ONCE AGAIN...THE POTENTIAL IS THERE FOR SOME
LINGERING FLURRIES OR STRATOCU STUCK BELOW THE INVERSION AROUND
2.5KFT. WILL PROBABLY BE SOMETHING SIMILAR TO THIS MORNINGS CLOUDS
FOR LOCATIONS FAVORED BY NORTH-NORTHWEST FLOW WEDNESDAY NIGHT INTO
THURSDAY. BUT WITH WINDS WEAKENING UNDER THE HIGH AND INCREASING DRY
AIR MOVING IN...WOULD THINK THAT THE LOW CLOUDS WOULD BE NEARLY GONE
ON THURSDAY NIGHT. WEDNESDAY NIGHT LOWS ARE TRICKY...SINCE THEY WILL
DEPEND ON WHERE THE CLOUDS ARE LOCATED. WHERE SKIES ARE
CLEAR...LIGHT WINDS AND PWAT VALUES TOWARDS 50 PERCENT OF NORMAL
WOULD LEAD TO GOOD RADIATIONAL COOLING. UPPER RIDGE WILL ALSO BUILD
OVER THE AREA DURING THIS TIME AND PRODUCE GRADUALLY WARMING
TEMPERATURES ALOFT...ESPECIALLY HEADING INTO THE WEEKEND AS
SOUTHERLY FLOW INCREASES WITH THE HIGH SLIDING TO THE EAST OF THE
AREA. THIS SHOULD TRANSITION THE AREA AWAY FROM THE BELOW NORMAL
TEMPERATURES THAT WE HAVE BEEN IN AND MORE NORMAL OR SLIGHT ABOVE
NORMAL HIGHS.
AS FOR PRECIPITATION HEADING INTO THE WEEKEND...THE CHANCES ALL
DEPEND ON THE STRENGTH OF THE UPPER RIDGE. THE FIRST SHORTWAVE WILL
RIDE UP THE UPPER RIDGE ON FRIDAY AND HEAD NORTHEAST TOWARDS JAMES
BAY ON FRIDAY NIGHT. 06Z GFS AND 00Z GEM HAVE IT FARTHER TO THE
SOUTHEAST AND MOVING ACROSS LAKE SUPERIOR...WHILE THE 00Z ECMWF
KEEPS IT WELL TO THE NORTHWEST IN ONTARIO. WITH THE SURFACE LOW
WELL TO THE NORTH OF THE AREA...SHOULD SEE A SURFACE TROUGH
PUSHING THROUGH THE AREA ON LATE FRIDAY NIGHT INTO SATURDAY. MODELS
VARYING ON TIMING AND AMOUNT OF MOISTURE ASSOCIATED WITH THE
SHORTWAVE AND THEN THE SURFACE TROUGH. THEY DO AGREE THAT DEEP
MOISTURE FOR WIDESPREAD SNOW SEEMS MARGINAL AND MORE LIKELY SEE
ISOLATED TO SCATTERED SNOW SHOWERS DURING THAT PERIOD.
UNCERTAINTY GROWS AFTER SATURDAY...AS THERE ARE LARGE MODEL AND
RUN-TO-RUN DIFFERENCES IN THE HANDLING OF THE UPPER LOW OVER THE
SOUTHWESTERN CONUS AND HOW THE NORTHERN AND SOUTHERN JET STREAMS
PHASE AS THE TROUGH SLIDES EAST. MODELS HAVE A DIFFICULT TIME WITH
PHASING SYSTEMS A DAY OR TWO OUT...SO DON/T HAVE ANY CONFIDENCE TO
GO MORE THAN A CONSENSUS CHANCE POPS FOR MONDAY WITH THE LOW MOVING
THROUGH THE GREAT LAKES. DESPITE THESE DIFFERENCES...BOTH THE LONGER
RANGE GFS/ECMWF DO SHOW THE UPPER TROUGH REESTABLISHING OVER THE
CENTRAL CONUS BY THE MIDDLE OF NEXT WEEK. THIS PRODUCES A POTENTIAL
FOR ANOTHER BELOW NORMAL TEMPERATURE PERIOD FOR THE UPPER GREAT
LAKES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1249 PM EST MON MAR 4 2013
EXPECT MVFR CIGS TO PERSIST AT CMX THROUGH THE AFTERNOON SUPPORTED
BY ENE ACROSS LAKE SUPERIOR. ALTHOUGH CONFIDENCE IS LIMITED...IMPROVEMENT
TO VFR IS EXPECTED THIS EVENING AS DRIER AIR UPSTREAM MOVES IN.
SATELLITE TRENDS AND FCST SOUNDINGS SUGGEST THAT CLOUDS SHOULD ERODE
AT SAW BY MID TO LATE AFTERNOON. INCREASING NE WINDS LATE TONIGHT
INTO TUE MORNING SHOULD AGAIN LEAD TO MVFR CIGS AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EST MON MAR 4 2013
AS LOW PRESSURE OVE THE DAKOTAS SLIDES TO THE SE...NE WINDS TO 30
KTS ARE EXPECTED MON NIGHT THROUGH TUE...ESPECIALLY OVER THE WRN
THIRD OF THE LAKE WHERE LOW LEVEL CONV IS STRONGEST. NORTH WINDS TO 25 KTS
CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY WINDS AND COLDER
TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT TIMES THROUGH
WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS LATER
WEDNESDAY INTO FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.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
1249 PM EST MON MAR 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM EST MON MAR 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A VIGOROUS SHORTWAVE TROUGH
OVER ERN MONTANA WITH A MID/UPPER LEVEL RIDGE EXTENDING FROM THE
PLAINS INTO THE UPPER GREAT LAKES. AT THE SFC...A RIDGE EXTENDED
FROM NRN MANITOBA INTO WRN UPPER MI. SHALLOW LOW-LVL MOISTURE AIDED
BY CONTRIBUTION OFF LAKE SUPERIOR IN NNE FLOW HAS GENERATED SOME
LAKE CLOUDS FOR AREAS EAST OF MQT. LACK OF RADAR RETURNS EARLY THIS
MORNING SUGGEST LTL MORE THAN FLURRIES ASSOC WITH THESE LAKE CLOUDS.
CLEAR SKIES OVER THE WEST HALF HAS RESULTED IN TEMPS FALLING INTO
THE SINGLE DIGITS BLO ZERO AT MANY LOCATIONS EARLY THIS MORNING.
TODAY...WEAK UPSLOPE NE FLOW INTO N CNTRL UPPER MI MAY GENERATE SOME
FLURRIES DESPITE INVERSION HEIGHTS BELOW 3K FT. WITH LOW CONFIDENCE
IN ANY MEASURABLE LES...HAVE DROPPED MENTION OF SLIGHT CHANCE POPS.
WITH ANTICYCLONIC/DIFLUENT ENE FLOW...ANY FLURRIES THAT FORM SHOULD
END BY MIDDAY. LOOK FOR MAX TEMPS TO REBOUND INTO THE UPPER 20S AND
LOWER 30S...PER FCST SOUNDINGS LOW LEVEL TEMP PROFILE.
TONIGHT...MODELS CONSISTENT IN SHOWING ERN MT SHORTWAVE DIVING WELL
SE OF THE UPPER GREAT LAKES LATER TONIGHT. WITH BEST Q-VECT CONV AND
WAA/ISENTROPIC LIFT STAYING GENERALLY SE OF FCST AREA ALONG TRACK OF
SHORTWAVE AND ASSOC INVERTED SFC TROUGH...MUCH OF CWA SHOULD STAY
DRY THROUGH TONIGHT UNDER INFLUENCE OF SFC HIGH PRESSURE RIDGE. KEPT
ONLY SLIGHT CHC POPS IN FCST OVER FAR WRN LAKE SUPERIOR LATE
TONIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 501 AM EST MON MAR 4 2013
AT 12Z TUE AN UPPER ANS SFC RIDGE WILL BE OVER THE ERN CWA...BUT
WILL SHIFT E AS AN UPPER TROUGH MOVES IN FROM THE W. THE UPPER
TROUGH WILL MOVE E OF THE CWA BY 00Z THU...BRINGING IN COLDER
INVERSION TOP TEMPS...BETTER SYNOPTIC LIFT AND MORE CYCLONIC
FLOW...WHICH WILL SUPPORT INCREASED LES WITH NE-N LOW LEVEL WINDS
TUE INTO THU. THE BEST COVERAGE AND INTENSITY OF LES IS EXPECTED
TUE/TUE NIGHT...BUT WILL STILL NOT BE ALL THAT HEAVY DUE TO MARGINAL
CONDITIONS AND LOW SNOW TO LIQUID RATIOS. THE SOUTHERN PART OF THE
UPPER TROUGH WILL BE CLOSED OFF AND WILL MOVE WELL S OF THE CWA ON
TUE...WITH SOME SYNOPTIC SNOW POSSIBLY CLIPPING THE IRONWOOD AREA
TUE...BUT ONLY MINOR SNOWFALL AMOUNTS WOULD BE POSSIBLE. WOULD
EXPECT LES TO TAPER OFF AND END WHEN WINDS TURN SLY THU AS A SFC
RIDGE MOVES THROUGH...BUT WARMING TEMPS AND ANTICYCLONIC FLOW WILL
KEEP LES FROM FORMING OFF LAKE MICHIGAN.
EXPECT A COUPLE OF SHORTWAVES TO MOVE NEARBY FRI AND SAT...BUT DO
NOT EXPECT MUCH IN THE WAY OF PRECIP...ESPECIALLY WHEN LOOKING AT
THE MORE CONTINUITOUS ECMWF AND GEM MODELS AS THE GFS DOES PUMP OUT
A GOOD AMOUNT OF PRECIP SAT INTO SUN. PREFERRED THE NON-GFS
SOLUTIONS FOR THIS PART OF THE FORECAST. THEN EXPECT SFC RIDGING TO
MOVE IN ON SUN.
TEMPS WILL GENERALLY BE ON THE RISE...WITH HIGHS AOA FREEZING IN
MOST LOCATIONS FROM THU ON. FOR THE WEEKEND...HIGH TEMPS WILL BE
AROUND 40 DEGREES ALONG THE WI BORDER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1249 PM EST MON MAR 4 2013
EXPECT MVFR CIGS TO PERSIST AT CMX THROUGH THE AFTERNOON SUPPORTED
BY ENE ACROSS LAKE SUPERIOR. ALTHOUGH CONFIDENCE IS LIMITED...IMPROVEMENT
TO VFR IS EXPECTED THIS EVENING AS DRIER AIR UPSTREAM MOVES IN.
SATELLITE TRENDS AND FCST SOUNDINGS SUGGEST THAT CLOUDS SHOULD ERODE
AT SAW BY MID TO LATE AFTERNOON. INCREASING NE WINDS LATE TONIGHT
INTO TUE MORNING SHOULD AGAIN LEAD TO MVFR CIGS AT ALL TAF SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 501 AM EST MON MAR 4 2013
STRONGEST WINDS THIS WEEK OCCUR THIS AFTERNOON THROUGH TUESDAY OVER
FAR WESTERN LAKE SUPERIOR AS A LOW PRESSURE SYSTEM MOVES JUST TO THE
SOUTH. EAST-NORTHEAST WINDS TO 30 KTS ARE A GOOD BET. MAY BE GALE
GUSTS TOWARD THE HEAD OF LK SUPERIOR AND ALONG THE MINNESOTA SHORE
MONDAY NIGHT INTO TUESDAY MORNING DUE TO COASTAL CONVERGENCE. NORTH
WINDS TO 25 KTS CONTINUE THROUGH TUESDAY NIGHT. DUE TO THE GUSTY
WINDS AND COLDER TEMPERATURES...FREEZING SPRAY WILL BE AROUND AT
TIMES THROUGH WEDNESDAY MORNING. WINDS DIMINISH TO LESS THAN 20 KTS
LATER WEDNESDAY INTO FRIDAY AS HIGH PRESSURE CROSSES THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
335 PM CST MON MAR 4 2013
.SHORT TERM...TONIGHT THROUGH THURSDAY
THE PRIMARY FORECAST CONCERNS DURING THIS PERIOD ARE PCPN AND WINDS
TONIGHT...WINDS ON TUESDAY AND POTENTIAL FOR CLOUD COVER FOR TUESDAY
NIGHT.
CLOSED LOW AT 500 MB WHICH WAS OVER EXTREME EASTERN MONTANA AT 12Z
WILL CONTINUE TO DIVE SOUTHEAST TONIGHT...REACHING THE BORDER AREA
OF SOUTH DAKOTA/MINNESOTA/IOWA BY 12Z TUESDAY AND THEN SOUTHERN
ILLINOIS BY 00Z WEDNESDAY. SURFACE ANALYSIS EARLY THIS AFTERNOON
SHOWED ONE LOW PRESSURE CENTER OVER SOUTH CENTRAL NORTH DAKOTA AND
ANOTHER OVER OKLAHOMA. AN INVERTED TROF EXTENDED NORTHWARD FROM
THE SOUTHERN LOW. NORTHERN LOW WILL PUSH SOUTHEAST AND WEAKEN
OVERNIGHT. FAIRLY TIGHT PRESSURE GRADIENT OVER THE AREA ALONG WITH
DECENT DOWNWARD MOMENTUM TRANSFER SHOULD RESULT IN GUSTY WINDS
LATER TONIGHT AND INTO TUESDAY. WILL LEAVE PREVIOUSLY ISSUED WIND
ADVISORY IN PLACE BUT EXTEND IT UNTIL 21Z. THIS CAN BE CANCELED IS
WINDS DECREASE EARLIER. ALSO ISSUED ANOTHER WIND ADVISORY SEGMENT
TO THE SOUTHEAST OF PREVIOUS ADVISORY FROM 8 AM TO 3 PM
TUESDAY...AS STRONGER WINDS OVERSPREAD MORE OF THE AREA.
RADAR ECHOES HAVE BEEN INCREASING TO OUR WEST...WITH SOME LIGHT SNOW
REPORTED IN PARTS OF SOUTHWEST NEBRASKA. RECENT HRRR AND RAP13 MODEL
RUNS INDICATE SOME PCPN WILL DEVELOP OVER ABOUT THE SOUTHEAST HALF
OF THE FORECAST AREA THIS EVENING...IN ASSOCIATION WITH 500-300 MB
Q VECTOR DIVERGENCE AND ELEVATED FRONTOGENESIS. RAP13 PCPN
AMOUNTS SEEM OVERDONE...BUT SCENARIO IS ALSO SUPPORTED BY 18Z NAM.
ON TUESDAY...FAIRLY TIGHT PRESSURE GRADIENT IS IN PLACE DURING THE
MORNING BUT THIS RELAXES IN THE AFTERNOON. THERE IS SOME SMALL
POTENTIAL FOR LIGHT SNOW TUESDAY...MAINLY FOR ABOUT THE NORTHEAST
ONE THIRD OF THE FORECAST AREA...BUT CHANCES ARE MUCH HIGHER FARTHER
TO THE EAST OF OUR AREA.
OTHERWISE...LOOK FOR MAINLY DRY CONDITIONS TUESDAY NIGHT AS HIGH
PRESSURE BUILDS IN. SOME MODELS SHOW LOW LEVEL MOISTURE MOVING INTO
THE AREA FROM THE NORTH...SO WILL HAVE TO WATCH THAT. FOR NOW...
HAVING CLEARING SKIES. THAT SURFACE RIDGE WILL PUSH OFF TO THE EAST
WEDNESDAY THROUGH THURSDAY WITH INCREASING SOUTH/SOUTHEAST WINDS...
MODERATING TEMPERATURES AND MAINLY DRY CONDITIONS.
MILLER
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
CONFIDENCE IS INCREASING THAT THE UPPER LEVEL LOW THAT WILL DIVE
INTO THE SOUTHWEST CONUS ON WED/THU WILL MOVE INTO THE PLAINS AT
SOME POINT NEXT WEEKEND. THE ECMWF/GEM HAVE REMAINED VERY CONSISTENT
OVER THE PAST COUPLE OF DAYS WHILE THE OPERATIONAL GFS HAS VARIED
WILDLY FROM THE 00Z/04 TO 12Z/O4 RUNS. THUS WILL LEAVE MUCH HEAVIER
ON THE EC/GEM/EC ENSEMBLE SOLUTIONS FOR THE TRACK OF THIS SYSTEM.
AHEAD OF THE SYSTEM/COLD FRONT WE SHOULD SEE A NICE DAY ON FRIDAY
WITH HIGHS ABOVE SEASONAL AVERAGES. THE COLD FRONT THEN MOVES
THROUGH THE FA ON THE WEEKEND WITH SLIGHTLY COOLER AIR MOVING INTO
THE REGION. THE GFS...ALTHOUGH CLOSER TO THE EC WITH THE 12Z/04
RUN...IS STILL TO FAST IN BRINGING PRECIP TO THE AREA. WILL HOLD
ONTO SOME POPS IN THE SW ON FRI NIGHT...BUT IT WILL LIKELY BE SAT OR
MAYBE EVEN SAT NIGHT BEFORE WE SEE THE BULK OF THE PRECIP ASSOCIATED
WITH THE UPPER LEVEL LOW HEAD INTO THE PLAINS.
THE EC IS VERY WARM FOR THIS SYSTEM AND WOULD HAVE LIMITED CHANCE OF
ANY FROZEN PRECIP AT ALL FOR OUR FA...AND WE WILL TREND THE FORECAST
THIS WAY. HAVE INCREASED OVERNIGHT LOWS AS WELL AS HIGHS A TOUCH FOR
MOST AREAS. REMOVED FZRA MENTION AND WENT WITH A RA/SN MIX IN THE
FAR NORTH AND OTHERWISE JUST RA OVER THE SRN 2/3RD OF THE FA. IT IS
IMPORTANT TO NOTE THAT THE FORECAST WILL HAVE CHANCES OF PRECIP FOR
SEVERAL PERIODS...BUT THIS MORE REFLECTS THE UNCERTAINTY IN THE
TIMING MORE THAN WE WILL HAVE CONTINUOUS RAIN OVER A 48 HOUR
PERIOD.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
PERIOD OF LOW MVFR TO IFR CEILINGS IS EXPECTED AT ALL SITES
TODAY...WITH IMPROVEMENT TO VFR BY AROUND MID-AFTERNOON AT KOFK
AND EARLY EVENING AT KOMA/KLNK. KOFK IS MOST AT RISK FOR IFR
CIGS...BUT FOR NOW HAVE KEPT OUT AS CLOUD BAND IS MOVING EASTWARD
AND MOST SURROUNDING SITES ARE ABOVE 1KFT. WINDS WILL INCREASE
LATE THIS EVENING AT KOFK...AND AROUND MIDNIGHT AT KOMA/KLNK.
MODEL SOLUTIONS AGAIN POINT TO POSSIBLE LOWER CEILINGS
OVERNIGHT...BUT HAVE BEEN BURNED BY THESE THE LAST COUPLE OF DAYS
AS MODELS ARE NOT HANDLING LOW-LEVL MOISTURE WELL AND AM
SKEPTICAL. FOR NOW...HAVE PUT IN A SCT MENTION AT MVFR
LEVEL...WITH MORE CLOUD MENTION AT VFR.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 8 AM TO 3 PM CST TUESDAY FOR NEZ015-032>034-
042>045-050-051-065-066-078.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST TUESDAY FOR
NEZ011-012-016>018-030-031.
IA...WIND ADVISORY FROM 8 AM TO 3 PM CST TUESDAY FOR IAZ043.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
228 PM EST MON MAR 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRIEFLY BUILD OVER THE CAROLINAS TODAY.
A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE CAROLINAS AND SOUTHERN
VIRGINIA TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
LITTLE CHANGE TO THE FORECAST FOR TODAY. NC LIES BETWEEN A SURFACE
LOW OVER MAINE AND WEAK HIGH PRESSURE OVER THE EASTERN GOMEX.
CLEAR SKIES WILL CONTINUE EAST OF THE MOUNTAINS WITH PW NEAR 0.10"
IN THE WAKE OF A VORT MAX EXITING THE NC COAST. RAP SOUNDINGS
SUGGEST WIND GUSTS TO AROUND 20MPH THIS MORNING SHOULD WEAKEN AFTER
18Z...SO HAVE ADJUSTED GUSTS DOWNWARD THIS AFTERNOON. GUIDANCE IS
IN GOOD AGREEMENT ON HIGHS OF 49-52 NORTH TO SOUTH. -SMITH
TONIGHT...MID LEVEL S/W RIDGE AND ATTENDANT SURFACE RIDGE WILL SCOOT
ACROSS THE FORECAST AREA. THE APPROACH OF A STRONG UPPER LEVEL LOW
DROPPING SEWD FROM THE UPPER MIDWEST WILL INCREASE/THICKEN CLOUD
COVER BY LATE EVENING-OVERNIGHT HOURS. GFS SPITS PUT A FEW
HUNDREDTHS IN THE NW PIEDMONT BY MORNING. THIS LOOKS OVERDONE
CONSIDERING THE DEGREE OF DRY AIR BELOW THE CLOUD BASE AND WEAK OR
NON-EXISTENT ISENTROPIC LIFT THROUGH 12Z TUE. FAVOR MIN TEMPS
LOW-MID 30S IN THE WEST AND FAR SOUTH WHERE CLOUDS EXPECTED TO BE
THICKER SOONER...TO AROUND 30 IN THE FAR EAST-NE WHERE THINNER CLOUD
COVER EXPECTED UNTIL MIDNIGHT OR SO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 225 PM MONDAY...
INTERESTING MULTI-THREAT WEATHER SYSTEM FOR MIDWEEK... WITH CONCERNS
ABOUT POSSIBLE STRONG/SEVERE WEATHER AS WELL AS SNOW AND WIND.
FOR TUESDAY: THE MID-UPPER VORTEX OVER NW IA TUESDAY MORNING WILL
DROP QUICKLY THROUGH SRN IL BY EARLY TUESDAY EVENING... CAUSING
RAPID SURFACE LOW DEEPENING JUST TO ITS ESE OVER KY. WITH THE POLAR
850 MB WARM FRONT EXPECTED TO HAVE SHIFTED TO OUR NORTHEAST BY
TUESDAY MORNING... MOIST ISENTROPIC UPGLIDE BEGINS IN EARNEST AFTER
12Z TUESDAY THROUGH THE 285K-300K LAYER ACCOMPANYING THE SECONDARY
850 MB WARM FRONT THAT WILL SURGE TO THE NNE THROUGH CENTRAL NC
TUESDAY... REACHING THE VA BORDER BY NIGHTFALL. THE GFS IS AS MUCH
AS 6 HRS FASTER THAN THE NAM BRINGING PRECIP THROUGH CENTRAL NC...
AND THIS FASTER SOLUTION HAS SOME SUPPORT FROM THE ECMWF AND SREF
MEAN AND IS PREFERRED. EXPECT OVERCAST SKIES SOON AFTER SUNRISE WITH
CLOUD BASES LOWERING AS THE LOW LEVEL MOISTURE TRANSPORT IN THE WARM
SECTOR STRENGTHENS. THE GFS DEPICTS A WEAK WEDGE REGIME AT ONSET AS
THE PRECIP ATTEMPTS TO LOCK IN THE SURFACE-BASED STABLE POOL IN THE
PIEDMONT... BUT THE RELATIVE WEAKNESS AND UNFAVORABLE LOCATION OF
THE PRECEDING SURFACE HIGH FAVORS ALLOWING THE WARM SECTOR TO
OVERTAKE THIS AIR MASS... THUS THE NOTABLY STABLE AIR SHOULD LINGER
OVER ONLY THE FAR NORTHERN PIEDMONT THROUGH TUESDAY. EXPECT VERY
LITTLE RAIN CONFINED TO THE FAR NORTH AND NW CWA IN THE MORNING...
THEN COVERAGE SHOULD INCREASE TO LIKELY ALONG AND NW OF THE I-85
CORRIDOR AS THE COLUMN MOISTENS FURTHER WITH STRENGTHENING MOIST
UPGLIDE. WITH WEAKER UPGLIDE AND A DEEPER DRY SUBCLOUD LAYER TO THE
SOUTH AND EAST OF RALEIGH... ANY RAIN HERE SHOULD BE LIGHTER WITH
MUCH LOWER COVERAGE. EXPECT HIGHS FROM 50 NEAR THE VA BORDER TO 64
IN THE FAR SOUTH AND SOUTHEAST CWA WITH THINNER CLOUDS AND BETTER
HEATING.
FOR TUESDAY NIGHT: THE INTENSE MID LEVEL VORTEX MOVES TO THE NRN
PIEDMONT BY 12Z WEDNESDAY... WHILE AT THE SURFACE... THE PRIMARY LOW
SHIFTS FROM ERN KY TOWARD SRN OH WITH A TRIPLE POINT LOW FORMING
OVER THE WRN PIEDMONT/SRN FOOTHILLS TUESDAY EVENING THEN MOVING TO
FAR SE VA BY DAWN WEDNESDAY. MODELS INDICATE A BAND OF SHOWERS AND
POSSIBLE STORMS JUST AHEAD OF THE COLD FRONT... FUELED BY STRONG
DEEP ASCENT GENERATED BY VIGOROUS UPPER DIVERGENCE (WITH THE 120+ KT
JET OVER THE SOUTHEAST STATES)... DCVA... AND INCOMING MASSIVE
HEIGHT FALLS OVER 260 METERS. WHILE THE OVERALL INSTABILITY IS
PROJECTED TO BE QUITE WEAK (UNDER 100 J/KG MLCAPE)... THE STRENGTH
OF THE DYNAMIC FORCING AND THE ANTICIPATED MID LEVEL DRY PUNCH AND
ITS POSSIBLE IMPACT ON INSTABILITY (ESPECIALLY WITH CONTINUED
WARM/MOIST NEAR-SURFACE AIR) WARRANTS INCLUSION OF THUNDER...
PRIMARILY BETWEEN 23Z AND 06Z... AFTER WHICH TIME THE SURFACE FRONT
SHOULD HAVE MOVED TO COASTAL NC AND BEYOND. WE DO HAVE SOME CONCERN
THAT WE COULD SEE A SURGE OF ENHANCED WINDS RIGHT BEHIND THE FRONT
DURING THE OVERNIGHT HOURS GIVEN THE POTENTIAL FOR INJECTION OF
STRATOSPHERIC AIR INTO THE TROPOSPHERE AS THE DYNAMIC TROPOPAUSE
DROPS TO BELOW 700 MB FROM 06Z-12Z. SO EVEN WITHOUT A LOT OF
INSTABILITY... GIVEN THE TREMENDOUS 60-80 KTS OF DEEP LAYER SHEAR
AND STEEPENING LAPSE RATES TO OVER 6.5 C/KM... WE MAY STILL SEE A
FEW STRONG AND POSSIBLY DAMAGING WIND GUSTS. THE RISK OF TORNADIC
ACTIVITY SHOULD BE FAIRLY LOW WITH THE WARM FRONT HAVING RETREATED
NORTH OF THE BORDER... HOWEVER WE WILL NEED TO KEEP A CLOSE EYE ON
ANY CONVECTION NEAR THE VORTICITY-RICH TRACK OF THE TRIPLE-POINT
LOW. BOTTOM LINE: WILL SWEEP CATEGORICAL POPS ACROSS CENTRAL NC
PRIMARILY DURING THE EVENING... SHOWERS WITH ISOLATED STORMS...
FOLLOWED BY A LOWER CHANCE OF SHALLOW RAIN SHOWERS TRENDING TO A
BRIEF RAIN/SNOW MIX OVERNIGHT (MAINLY OVER THE FAR NORTHERN CWA)
ACCOMPANYING THE 925-850 MB FRONT... AND A PERIOD OF STRONGER WINDS.
THE LIKELY SCARCITY OF MOISTURE ABOVE -12C OVERNIGHT AND MARGINAL TO
UNFAVORABLE SURFACE TEMPS SHOULD LIMIT THE THREAT OF ANY
ACCUMULATING FROZEN PRECIP TUESDAY NIGHT. LOWS 33 WEST TO 43 EAST.
FOR WEDNESDAY: ATTENTION THEN SHIFTS TO THE POTENTIAL FOR BANDED
SNOW AS THE SURFACE LOW MOVES FROM SE VA EARLY TO THE ENE TO OFF
DELMARVA BY LATE IN THE DAY. BASED ON THE PROJECTED TRACK OF THE
850-700 MB LOW AND FRONTOGENESIS... THE MOST INTENSE BANDED SNOWFALL
SHOULD HOLD OVER WRN/CENTRAL VA INTO MD/DC/SE PA... ALTHOUGH THE
TAIL END OF SUCH A BAND COULD CERTAINLY BRUSH ACROSS THE VA/NC
BORDER COUNTIES TO AREAS NORTH AND NE OF ROCKY MOUNT. MID LEVEL
LAPSE RATES OVER 6.0 C/KM WRAP AROUND INTO NORTH CENTRAL NC (AS DOES
A 50-60 KT LOW LEVEL JET)... THUS THERE THE POTENTIAL EXISTS FOR
UPRIGHT CONVECTION FROM OUR FAR NORTHERN COUNTIES TO THE
NORTH/NORTHEAST. THE GFS SUGGESTS THAT MOISTURE AND ASCENT ONLY
BRIEFLY REACH INTO THE -12C TO -18C LAYER OVER THE NORTHERN AND NE
CWA WEDNESDAY... PLUS THE NEAR-SURFACE AIR IS EXPECTED TO WARM WELL
ABOVE FREEZING... SO ANY OPPORTUNITY FOR APPRECIABLE SNOW IN OUR
AREA SHOULD BE FAIRLY QUICK AND AREALLY LIMITED. THE UNFAVORABLE
TIME OF DAY IS ALSO A MITIGATING FACTOR WITH AT LEAST SOME DAYTIME
HEATING TAKING PLACE. THAT SAID... ANY SHIFT IN THE FORECAST TRACK
OF THE SURFACE AND MID LEVEL LOW COULD BRING THE COLDER AIR AND MORE
FOCUSED SNOW BANDING SOUTHWARD INTO CENTRAL NC... SO VIGILANCE IS
CERTAINLY WARRANTED HERE. WILL HOLD ONTO GOOD CHANCE TO LIKELY POPS
MAINLY NORTH AND NE OF RALEIGH... KEEPING IT A RAIN/SNOW MIX AS
PARTIAL THICKNESSES HOVER AROUND THE MOSTLY-SNOW/INDETERMINATE
PORTION OF THE CLIMO-BASED NOMOGRAM. THE TEMP FORECAST IS A TOUGH
ONE... AS LOW LEVEL THICKNESSES SHOULD BE COOL (ABOUT 20 METERS
ABOVE NORMAL) BUT NOT REMARKABLY SO... AND THE LOWEST 5000 FT OR SO
SHOULD BECOME WELL-MIXED THROUGH THE DAY WITH A NNWRLY DOWNSLOPE
COMPONENT ESPECIALLY AFFECTING THE WRN AND SRN CWA. HAVE ADJUSTED
HIGHS UPWARD A BIT TO RANGE FROM 43 FAR NORTH TO 54 SOUTH. THE
STRENGTHENING MSLP GRADIENT AND AFOREMENTIONED LOW LEVEL JET WILL
YIELD WINDY CONDITIONS... WITH NW WINDS SUSTAINED AT 15-25 MPH
LIKELY GUSTING OVER 35 MPH... NOT FAR FROM WIND ADVISORY CRITERIA.
FOR WEDNESDAY NIGHT: EXPECT GRADUALLY CLEARING SKIES AND DECREASING
WINDS (BUT STILL RATHER BREEZY) AS THE COASTAL STORM MOVES OUT OVER
THE ATLANTIC... AND THE COLUMN OVER CENTRAL NC DRIES AND STABILIZES.
WITH THE NEAR-SURFACE AIR REMAINING STIRRED OVERNIGHT... EXPECT LOWS
AROUND 30-35 DESPITE THE COOLER AIR MASS BUILDING IN FROM THE WEST.
-GIH
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 AM MONDAY...
THE DEEP LOW PRESSURE SYSTEM (WHICH IS EXPECTED TO MOVE ACROSS THE
REGION TUESDAY INTO WEDNESDAY) WILL SHIFT SLOWLY OFF TO THE EAST OF
THE AREA LATE WEEK... WHILE SURFACE HIGH PRESSURE BUILDS INTO THE
AREA AND HEIGHTS ALOFT RISE. SUBSIDENCE BEHIND THE EXITING SYSTEM
WILL PROVIDE THE AREA WITH SUNNY TO MOSTLY SUNNY SKIES FOR LATE
WEEK. HOWEVER... GIVEN THE NORTHERLY/NORTHWESTERLY FLOW... WITH AT
TIME BREEZE SURFACE WINDS ON THURSDAY... EXPECT TEMPS WILL REMAIN
BELOW NORMAL THROUGH AT LEAST THURSDAY AND FRIDAY. THUS... WILL GO
WITH HIGHS RANGING FROM GENERALLY THE UPPER 40S TO MID 50S THURSDAY
TO THE MID TO UPPER 50S FRIDAY. LOWS DURING THIS TIME AREA EXPECTED
TO BE IN THE UPPER 20S TO LOWER 30S (FRIDAY AND SATURDAY MORNINGS).
THE SURFACE RIDGE AXIS IS EXPECTED TO SHIFT TO THE EAST OF THE AREA
ON SATURDAY... YIELDING WARMING CONDITIONS... WITH THE NEXT
SIGNIFICANT SYSTEM EXPECTED TO REMAIN TO THE WEST OF THE AREA
THROUGH THE END OF THE FORECAST PERIOD. THUS... WILL CONTINUE DRY
CONDITIONS... WITH WARMING TEMPS. HOWEVER... EXPECTED CLOUD COVER TO
INCREASE DURING THE LATTER HALF OF THE WEEKEND AS THE NEXT SYSTEM
APPROACHES... ALONG WITH POSSIBLY SOME MID AND HIGH LEVEL CLOUD
COVER ASSOCIATED WITH A PASSING NORTHERN STREAM SYSTEM. THIS YIELDS
EXPECTED HIGH TEMPS NEAR NORMAL ON SATURDAY TO LOWER TO MID 60S
SUNDAY... WITH LOW TEMPS SUNDAY MORNING IN THE UPPER 30S TO AROUND
40.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 100 PM MONDAY...
VFR CONDITIONS OBSERVED ACROSS CENTRAL NC. NORTHWESTERLY WIND GUSTS
HAVE RELAXED A BIT AND BECOME MORE SPORADIC. THIS TREND WILL
CONTINUE THIS AFTERNOON...BECOMING LESS THAN 5KT AND WESTERLY THIS
EVENING. A LOW PRESSURE SYSTEM DIPPING OUT OF THE UPPER MIDWEST
WILL APPROACH FROM THE WEST-NORTHWEST ON TUESDAY...CROSSING CENTRAL
NC TUESDAY EVENING/NIGHT. WHILE THE MAIN SHIELD OF PRECIPITATION
ASSOCIATED WITH THE LOW WONT ARRIVE UNTIL AFTER THE TAF PERIOD...A
FEW SHOWERS MAY BE POSSIBLE AT KGSO/KINT BY 18Z. HOWEVER... BASED
ON LOW CONFIDENCE IN THE EXACT TIMING OF INITIAL PRECIP...HAVE
CHOSEN NOT TO INCLUDE ANY MVFR CEILINGS IN THE CURRENT TAF.
OUTLOOK...
A AREA OF LOW PRESSURE WILL CROSSING CENTRAL NC TUESDAY
EVENING/NIGHT. SHOWERS...AND POSSIBLY A FEW ISOLATED
THUNDERSTORMS...WILL IMPACT THE AREA BETWEEN ROUGHLY 21Z TUESDAY AND
09Z WEDNESDAY. SOME IMPROVEMENT OF CONDITIONS WILL BE POSSIBLE
WEDNESDAY MORNING BEFORE ANOTHER ROUND OF RAIN/SNOW FILLS BACK IN
ACROSS THE NORTHEASTERN HALF OF NC WEDNESDAY AFTERNOON. THIS SHOULD
MOSTLY IMPACT POINTS FROM KRDU TO KRWI AND NORTHWARD. WINDS
INITIALLY OUT OF THE SOUTH TUESDAY NIGHT WILL SWING AROUND TO
WESTERLY ON WEDNESDAY...POTENTIALLY GUSTING TO AROUND 30MPH
WEDNESDAY AFTERNOON.
VFR CONDITIONS ARE EXPECTED TO RETURN BY THURSDAY AND LAST INTO THE
WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...HARTFIELD
LONG TERM...BSD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 PM EST MON MAR 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRIEFLY BUILD OVER THE CAROLINAS TODAY.
A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE CAROLINAS AND SOUTHERN
VIRGINIA TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...
LITTLE CHANGE TO THE FORECAST FOR TODAY. NC LIES BETWEEN A SURFACE
LOW OVER MAINE AND WEAK HIGH PRESSURE OVER THE EASTERN GOMEX.
CLEAR SKIES WILL CONTINUE EAST OF THE MOUNTAINS WITH PW NEAR 0.10"
IN THE WAKE OF A VORT MAX EXITING THE NC COAST. RAP SOUNDINGS
SUGGEST WIND GUSTS TO AROUND 20MPH THIS MORNING SHOULD WEAKEN AFTER
18Z...SO HAVE ADJUSTED GUSTS DOWNWARD THIS AFTERNOON. GUIDANCE IS
IN GOOD AGREEMENT ON HIGHS OF 49-52 NORTH TO SOUTH. -SMITH
TONIGHT...MID LEVEL S/W RIDGE AND ATTENDANT SURFACE RIDGE WILL SCOOT
ACROSS THE FORECAST AREA. THE APPROACH OF A STRONG UPPER LEVEL LOW
DROPPING SEWD FROM THE UPPER MIDWEST WILL INCREASE/THICKEN CLOUD
COVER BY LATE EVENING-OVERNIGHT HOURS. GFS SPITS PUT A FEW
HUNDREDTHS IN THE NW PIEDMONT BY MORNING. THIS LOOKS OVERDONE
CONSIDERING THE DEGREE OF DRY AIR BELOW THE CLOUD BASE AND WEAK OR
NON-EXISTENT ISENTROPIC LIFT THROUGH 12Z TUE. FAVOR MIN TEMPS
LOW-MID 30S IN THE WEST AND FAR SOUTH WHERE CLOUDS EXPECTED TO BE
THICKER SOONER...TO AROUND 30 IN THE FAR EAST-NE WHERE THINNER CLOUD
COVER EXPECTED UNTIL MIDNIGHT OR SO.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 420 AM MONDAY...
QUICK UPDATE BELOW TO WEDNESDAY PERIOD FOR WINDS.
TUESDAY AND TUESDAY NIGHT...
THE APPROACH OF A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL CAUSE
WEATHER CONDITIONS TO DETERIORATE ACROSS CENTRAL NC TUESDAY. THE
APPROACH OF THIS SYSTEM WILL ENHANCE THE 850MB SLY FLOW BY MID DAY
AND CONTINUE THROUGH THE AFTERNOON HOURS. RAIN INITIALLY FALLING
THROUGH THE DRY SUB-CLOUD LAYER WILL LEAD TO EVAPORATIVE COOLING AND
AN IN-SITU CAD EVENT ACROSS THE FAR NORTHERN PIEDMONT. THIS CAD
SHOULD BE QUITE SHALLOW AND MAY BE EASILY SCOURED OUT BY
STRENGTHENING LOW LEVEL SLY FLOW. DO NOT EXPECT MAX TEMPS FOR THE
DAYLIGHT HOURS TO OCCUR ACROSS THE FAR NORTHERN COUNTIES UNTIL CLOSE
TO SUNSET. MOS GUIDANCE APPEARS TOO WARM CONSIDERING THE POTENTIAL
FOR THE IN-SITU CAD...BUT DID ADJUST MAX TEMPS UP 3-5 DEGREES FROM
PREVIOUS FORECAST.
NEAR TERM MODEL GUIDANCE IN GENERAL AGREEMENT ON THE PLACEMENT OF
850MB WARM FRONT ACROSS THE NORTHERN PIEDMONT INTO THE NORTHERN
COASTAL PLAIN LATE TUESDAY AFTERNOON-TUESDAY EVENING. EXPECT AXIS
OF MODERATE RAIN TO SET-UP ALONG THIS FEATURE. FARTHER
SOUTH...EXPECT PRECIP TO BE MORE SHOWERY IN NATURE. MID LEVEL LAPSE
RATES STILL INCREASE TO AROUND 7 DEG C/KM BY 00Z WED. THUS THE IDEA
OF ELEVATED CONVECTION LATE TUESDAY INTO TUESDAY EVENING STILL
APPEARS PROBABLE...ESPECIALLY TUESDAY EVENING WHEN MID LEVEL TROUGH
AND SFC LOW TRAVERSES THE REGION. WHILE KINEMATICS SUPPORTIVE OF THE
POTENTIAL FOR STRONG CONVECTION...LACK OF SURFACE BASED INSTABILITY
WILL LIMIT SEVERE WEATHER ATTRIBUTES WITH THE CONVECTION AT THIS
TIME.
WILL MAINTAIN FORECAST CONTINUITY OF GREATER PRECIP CHANCES TUESDAY
AFTERNOON AND TUESDAY NIGHT WITH LIKELY TO CATEGORICAL POPS DURING
THIS PERIOD. DID GO WITH A SLIGHTLY SLOWER PRECIP ARRIVAL
TUESDAY MORNING. AS SYSTEM BEGINS TO DEPART THE REGION TOWARD
DAYBREAK WEDNESDAY...SHARPLY COLDER AIR ALOFT WILL BRING A THREAT OF
RAIN MIXED WITH SNOW TO THE NW PIEDMONT. -WSS
WEDNESDAY AND WEDNESDAY NIGHT:
MODELS ARE COMING INTO BETTER AGREEMENT ON WEDNESDAY... SHOWING THE
SURFACE LOW INVOF THE NC/VA BORDER NEAR THE COASTAL REGION BY 12Z
WEDNESDAY... WITH THE 500 MB LOW QUICKLY MOVING ACROSS OUR AREA AND
INTO THE SAME GENERALLY AREA BY 18Z WEDNESDAY. THE GFS/NAM/ECMWF
HAVE TRENDED A BIT DRIER ACROSS THE AREA ON WEDNESDAY (WITH LITTLE
IF ANY PRECIP ACROSS THE SOUTHWEST NOW AFTER 12Z)... WITH THE SLIGHT
JOG TO THE NORTH WITH THE TRACK OF THE LOW... ALLOWING MORE OF A
DRYING NW TO NORTHERLY FLOW IN THE WAKE OF THE PASSING MID LEVEL
LOW. HOWEVER... IT STILL APPEAR LIKELY THAT WE WILL SEE SOME PRECIP
FILL BACK IN ACROSS THE NORTHEASTERN HALF OF THE CWA WITH STEEPENING
LAPSE RATES AND A POSSIBLE DEFORMATION BAND EXTENDING ACROSS OUR
NORTH/NORTHEAST (WITH THE MORE SIGNIFICANT PRECIP TO THE
NORTH/NORTHEAST OF OUR AREA). THE GFS BEGINS TO SHOW SIGNS OF THE
SYSTEM LIFTING OFF/MEANDERING MORE NORTH/NORTHEASTWARD WEDNESDAY
AFTERNOON/NIGHT. FOR THIS REASON HAVE ELECTED TO GO WITH MORE OF A
BLEND OF THE NAM/ECMWF FOR POPS/QPF LATE WEDNESDAY MORNING THROUGH
WEDNESDAY NIGHT... AS WE THINK THE BLOCKING HIGH ALOFT ACROSS SE
CANADA SHOULD HELP PREVENT A MORE NORTH/NORTHEASTWARD TRACK (WHICH
THE GFS HAS). THUS... WITH LOW LEVEL THICKNESS CRASHING AND
SUPPORTIVE OF ALL SNOW ACROSS THE NORTHEASTERN HALF (WHERE PRECIP IS
EXPECTED AND SATURATION RETURNING INTO THE -10 TO -20 LAYER C) OF
CENTRAL NC WE MAY SEE SOME ACCUMULATING SNOW (POSSIBLY AT FIRST
MIXED WITH RAIN... DEPENDING ON TEMPS IN THE BOUNDARY LAYER AND
LOCATIONS OF THE DEFORMATION BAND ALONG WITH SATURATION ALOFT)...
ESPECIALLY ACROSS THE FAR NORTHEASTERN PIEDMONT AND NORTHERN COASTAL
PLAIN. GIVEN WE ARE STILL TALKING ABOUT THE MAIN TIME FRAME FOR
ACCUMULATING SNOWFALL BEING WEDNESDAY MID/LATE MORNING INTO THE
AFTERNOON/EARLY EVENING WE WILL NOT ISSUE A WINTER STORM WATCH AT
THIS TIME. HOWEVER... IF FORECAST MODELS CONTINUE TO INDICATE THE
DEFORMATION BAND PIVOTING THROUGH OUR NORTH/NORTHEASTERN COUNTIES
THEN A WINTER STORM WATCH MAYBE NEEDED IN FUTURE FORECAST WITH THE
POTENTIAL FOR SOME DECENT ACCUMULATIONS NORTH OF A LINE FROM ROXBORO
TO LOUISBURG TO ROCKY MOUNT. IN ADDITION TO THE THREAT OF SNOW...
WNW TO NW WINDS WILL STRENGTHEN AS AS THE SYSTEM DEEPENS AND BECOMES
MORE VERTICALLY STACKED ON WEDNESDAY. THUS... THINK WE COULD SEE
WINDS IN THE 20 TO 25 MPH RANGE SUSTAINED... WITH GUSTS AS HIGH AS
30 TO 35 MPH WEDNESDAY... WHICH COULD CREATE LOW VISBYS IN AREAS OF
SNOW. HIGH TEMPS WILL BE QUITE DIFFICULT... WITH THE PRECIP ACROSS
THE NORTHEAST... WITH SKIES EVEN BEGIN TO CLEAR OUT A BIT ACROSS THE
FAR SOUTHWEST LATE IN THE DAY. THIS WILL YIELD A NON-DIURNAL TREND.
THIS YIELDS HIGH TEMPS RANGING FROM THE MID TO UPPER 30S
NORTH/NORTHEAST TO MID TO UPPER 40S SOUTH/WEST. SKIES WILL BEGIN TO
SLOWLY CLEAR FROM SOUTHWEST TO NORTHEAST ON THURSDAY MORNING... WITH
POSSIBLY THE TREAT OF SOME BLACK ICE. EXPECT LOW TEMPS TO RANGE FROM
THE LOWER TO MID 30S. -BSD
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 AM MONDAY...
THE DEEP LOW PRESSURE SYSTEM (WHICH IS EXPECTED TO MOVE ACROSS THE
REGION TUESDAY INTO WEDNESDAY) WILL SHIFT SLOWLY OFF TO THE EAST OF
THE AREA LATE WEEK... WHILE SURFACE HIGH PRESSURE BUILDS INTO THE
AREA AND HEIGHTS ALOFT RISE. SUBSIDENCE BEHIND THE EXITING SYSTEM
WILL PROVIDE THE AREA WITH SUNNY TO MOSTLY SUNNY SKIES FOR LATE
WEEK. HOWEVER... GIVEN THE NORTHERLY/NORTHWESTERLY FLOW... WITH AT
TIME BREEZE SURFACE WINDS ON THURSDAY... EXPECT TEMPS WILL REMAIN
BELOW NORMAL THROUGH AT LEAST THURSDAY AND FRIDAY. THUS... WILL GO
WITH HIGHS RANGING FROM GENERALLY THE UPPER 40S TO MID 50S THURSDAY
TO THE MID TO UPPER 50S FRIDAY. LOWS DURING THIS TIME AREA EXPECTED
TO BE IN THE UPPER 20S TO LOWER 30S (FRIDAY AND SATURDAY MORNINGS).
THE SURFACE RIDGE AXIS IS EXPECTED TO SHIFT TO THE EAST OF THE AREA
ON SATURDAY... YIELDING WARMING CONDITIONS... WITH THE NEXT
SIGNIFICANT SYSTEM EXPECTED TO REMAIN TO THE WEST OF THE AREA
THROUGH THE END OF THE FORECAST PERIOD. THUS... WILL CONTINUE DRY
CONDITIONS... WITH WARMING TEMPS. HOWEVER... EXPECTED CLOUD COVER TO
INCREASE DURING THE LATTER HALF OF THE WEEKEND AS THE NEXT SYSTEM
APPROACHES... ALONG WITH POSSIBLY SOME MID AND HIGH LEVEL CLOUD
COVER ASSOCIATED WITH A PASSING NORTHERN STREAM SYSTEM. THIS YIELDS
EXPECTED HIGH TEMPS NEAR NORMAL ON SATURDAY TO LOWER TO MID 60S
SUNDAY... WITH LOW TEMPS SUNDAY MORNING IN THE UPPER 30S TO AROUND
40.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 100 PM MONDAY...
VFR CONDITIONS OBSERVED ACROSS CENTRAL NC. NORTHWESTERLY WIND GUSTS
HAVE RELAXED A BIT AND BECOME MORE SPORADIC. THIS TREND WILL
CONTINUE THIS AFTERNOON...BECOMING LESS THAN 5KT AND WESTERLY THIS
EVENING. A LOW PRESSURE SYSTEM DIPPING OUT OF THE UPPER MIDWEST
WILL APPROACH FROM THE WEST-NORTHWEST ON TUESDAY...CROSSING CENTRAL
NC TUESDAY EVENING/NIGHT. WHILE THE MAIN SHIELD OF PRECIPITATION
ASSOCIATED WITH THE LOW WONT ARRIVE UNTIL AFTER THE TAF PERIOD...A
FEW SHOWERS MAY BE POSSIBLE AT KGSO/KINT BY 18Z. HOWEVER... BASED
ON LOW CONFIDENCE IN THE EXACT TIMING OF INITIAL PRECIP...HAVE
CHOSEN NOT TO INCLUDE ANY MVFR CEILINGS IN THE CURRENT TAF.
OUTLOOK...
A AREA OF LOW PRESSURE WILL CROSSING CENTRAL NC TUESDAY
EVENING/NIGHT. SHOWERS...AND POSSIBLY A FEW ISOLATED
THUNDERSTORMS...WILL IMPACT THE AREA BETWEEN ROUGHLY 21Z TUESDAY AND
09Z WEDNESDAY. SOME IMPROVEMENT OF CONDITIONS WILL BE POSSIBLE
WEDNESDAY MORNING BEFORE ANOTHER ROUND OF RAIN/SNOW FILLS BACK IN
ACROSS THE NORTHEASTERN HALF OF NC WEDNESDAY AFTERNOON. THIS SHOULD
MOSTLY IMPACT POINTS FROM KRDU TO KRWI AND NORTHWARD. WINDS
INITIALLY OUT OF THE SOUTH TUESDAY NIGHT WILL SWING AROUND TO
WESTERLY ON WEDNESDAY...POTENTIALLY GUSTING TO AROUND 30MPH
WEDNESDAY AFTERNOON.
VFR CONDITIONS ARE EXPECTED TO RETURN BY THURSDAY AND LAST INTO THE
WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS/SMITH
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
310 PM CST MON MAR 4 2013
.SHORT TERM...TONIGHT THROUGH THURSDAY
CHALLENGES ABOUND WITH ONGOING WINTER STORM...OF GREATEST CONCERN
WILL BE SNOW AMOUNTS AND ASSOCIATED HEADLINES. MODELS CONTINUE TO
UNDERESTIMATE THE STRENGTH OF THE DRYING FROM BOTH THE DRY SLOT TO
THE SOUTH AND ARCTIC HIGH TO THE NORTH. OVERALL...RAP SEEMS TO
HAVE THE BEST HANDLE ON REALITY AND WILL FOLLOW ITS OUTPUT AND
THE LATEST OBSERVATIONAL TRENDS FOR THE NEXT SEVERAL HOURS.
SURFACE LOW AS OF 21 UTC HAS FINALLY TURNED TO THE SOUTH...
CENTERED TO THE SOUTHEAST OF BISMARCK BY ABOUT 50 MILES. RAP SHOWS
THE SURFACE LOW CONTINUING ITS SOUTHEASTWARD TRACK...NEARING
ABERDEEN BETWEEN 03 AND 06 UTC THIS EVENING. MODERATE TO HEAVY
SNOW BAND FROM MINOT TO GRAND FORKS TO DETROIT LAKES WILL CONTINUE
TO PIVOT AROUND THE LOW...IMPACTING MOST OF THE FORECAST AREA
THIS EVENING AND THROUGH THE NIGHT. THE DRY SLOT HAS MOVED INTO
EASTERN ND ALONG AND WEST OF A LINE FROM DEVILS LAKE TO GRAND
FORKS TO FARGO AND EXPECT A BREAK IN SNOWFALL IN THIS AREA LATE
THIS AFTERNOON AND EVENING BEFORE LIGHT WRAP-AROUND SNOW MOVES
THROUGH IN THE WAKE OF THE SURFACE LOW.
HIGHEST SNOW TOTALS SO FAR HAVE BEEN ALONG AND SOUTH OF THE
CANADIAN BORDER ACROSS THE DEVILS LAKE BASIN AND INTO THE NORTHERN
VALLEY WHERE OVER A FOOT HAS ACCUMULATED. FARTHER SOUTH AND EAST
FROM EAST CENTRAL ND INTO THE CENTRAL VALLEY HAS RECEIVED 5 TO 8
INCHES. VERY LITTLE SNOW HAS FALLEN SO FAR FROM FERGUS FALLS TO
DETROIT LAKES/PARK RAPIDS NORTHWARD TO BEMIDJI AND ROSEAU/
BAUDETTE WITH ONLY AN INCH OR LESS ACCUMULATION. RAP SUGGESTS THIS
AREA WILL FILL-IN THIS EVENING AND OVERNIGHT AS THE SURFACE LOW
MOVES INTO SD AND SOUTHWEST MN. AS A RESULT...WILL KEEP WINTER
STORM WARNING IN PLACE FOR THESE AREAS WITH SNOW TOTALS BY TUESDAY
MORNING IN THE 4 TO 7 INCH RANGE. BACK TO THE NORTH AND WEST
ANOTHER 1 TO 4 INCHES ARE POSSIBLE OVERNIGHT.
WINDS WILL SHIFT TO THE NORTH ALONG AND WEST OF THE VALLEY LATE
THIS EVENING AND OVERNIGHT. ALTHOUGH NOT OVERLY STRONG...WIND
SPEEDS SHOULD BE HIGH ENOUGH FOR PERIODS OF BLOWING AND DRIFTING
SNOW AND WILL INCLUDE THIS IN THE GRIDS. WITH CLOUD COVER AND WIND
OVERNIGHT...EXPECT ELEVATED TEMPERATURES WITH TUESDAY MORNING LOWS
IN THE MID TO UPPER TEENS.
LIGHT SNOW WILL LINGER EAST OF THE VALLEY THROUGH TUESDAY MORNING
AND DEPENDING ON HOW MUCH SNOW ACCUMULATES OVERNIGHT...THE WINTER
STORM WARNING MAY NEED TO BE EXTENDED. FOR AREAS TO THE WEST...
EXPECT VERY GRADUAL DRYING AND CLEARING. HIGHS TOMORROW WILL RANGE
FROM THE UPPER TEENS TO MID 20S.
WEDNESDAY WILL BE DRY WITH PERIODS OF SUNSHINE AS SURFACE HIGH
PRESSURE BUILDS ACROSS THE REGION. WILL MAINTAIN 20 TO 30 POPS
ACROSS THE NORTH ON THURSDAY AS A SHORT-WAVE MOVES THROUGH
SOUTHWEST FLOW ALOFT. HOWEVER...LATEST MODEL TRENDS PLACE THE
MAJORITY OF SNOW NORTH OF THE BORDER...SO NOT EXPECTING MUCH IN
THE WAY OF ACCUMULATION. BY THURSDAY...TEMPERATURES WILL RISE INTO
THE UPPER 20S TO LOW 30S.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
SW FLOW ALOFT IS EXPECTED TO BEGIN THE PERIOD...WITH THE CHANCE OF
SOME SNOW THU NIGHT. THEREAFTER...THE FLOW BECOMES SOMEWHAT
SPLIT...ALTHOUGH MODELS DIFFER ON JUST HOW MUCH INFLUENCE A SOUTHERN
STREAM WAVE MAY HAVE LATER IN THE WEEKEND. FOR NOW WILL KEEP SOME
LOW POPS THU NIGHT...THEN AGAIN LATER IN THE WEEKEND INTO EARLY NEXT
WEEK FOR MAINLY THE SOUTHERN AREAS. TEMPS SHOULD MODERATE TO NEAR
NORMAL THIS WEEKEND...WITH OVERALL CONFIDENCE NOT VERY HIGH WITH
THIS FORECAST.
&&
.AVIATION...
EXPECT CONDITIONS TO VARY FROM IFR TO LOW END MVFR IN EITHER CIGS
OR VSBY IN SNOW/BLSN AT MOST TAF SITES THRU TONIGHT. EXPECT A
SOUTHEAST TO EAST WIND 15 TO 25KTS TURNING NORTH IN ERN ND LATE
TONIGHT-TUES WITH GUSTS AT TIMES TO 30KT POSSIBLE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ049-052-
053.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR NDZ006>008-
014>016-024-026>030-038-039-054.
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ029.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MNZ001>009-
013>017-022>024-027-028-030>032-040.
&&
$$
ROGERS/DK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1015 AM CST MON MAR 4 2013
.DISCUSSION.../ISSUED AT 1015 AM CST/
NARROW FAST MOVING BAND OF SNOW SHOWERS MOVING ACROSS FAR EASTERN SD
HAS REQUIRED SOME SHORT TERM VERY FINE TUNING OF GRIDS FOR THE END
OF THE MORNING...AND MAY HAVE TO EXTEND THAT INTO THIS AFTERNOON.
FORTUNATELY IT IS TOO NARROW AND MOVING TOO FAST TO PROVIDE MORE
THAN A QUARTER INCH OR SO OF SNOW. THIS IS NOT DIRECTLY ASSOCIATED
WITH THE UPPER SUPPORT THAT IS EXPECTED TO PROVIDE LIFT FOR THE
REDEVELOPMENT OF SNOW OVER SOUTHWEST MN BACK TO BROOKINGS LATER THIS
AFTERNOON AS THE UPPER LOW DIGS IN AND ROTATES...BUT THAT
DEVELOPMENT SHOULD BE FAST ALSO...AND SO FAR HAVE NOT SEEN A NEED TO
CHANGE. HAVE DROPPED THE FRINGE ADVISORY AREA WHICH INCLUDES SIOUX
FALLS WITH NO FREEZING RAIN OR FREEZING DRIZZLE...BUT HAVE KEPT IT
FURTHER NORTHEAST DESPITE SEVERAL HOURS OF LITTLE HAPPENING OUTSIDE
THESE SNOW SHOWERS...FOR THE VERY REASON OF RAPID REDEVELOPMENT.
WINDS AND TEMPERATURES LOOK OK AND NO REASON AT THIS TIME TO CHANGE
WIND ADVISORY FOR LATE TONIGHT INTO TUESDAY WEST AND FAR SOUTH.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
LARGELY MVFR STRATUS BEGINNING TO SPREAD BACK ACROSS WESTERN PARTS
OF FORECAST AREA WHILE EASTERN AREAS REMAIN UNDER LINGERING MVFR/IFR
CEILINGS. RAP CONTINUES TO HAVE BEST GRASP ON NEAR TERM MOISTURE AND
PRECIPITATION TRENDS...AND ASIDE FROM NARROW BAND OF SHOWERY PRECIP
RIGHT ALONG A WIND SHIFT LINE ENTERING FAR WESTERN FORECAST AREA
WHICH COULD AFFECT KHON AT THE START OF THE PERIOD...EXPECT LARGELY
DRY FORECAST FOR THE TAF SITES THROUGH THE DAY. HOWEVER...AS THIS
FEATURE TRANSLATES EAST INTO I-29 CORRIDOR...MID LEVEL MOISTURE
BECOMES MORE SCARCE... BUT ENOUGH WEAK LIFT PERSISTS ABOVE STRATUS
DECK THAT WILL KEEP BRIEF PERIOD OF POTENTIAL FREEZING DRIZZLE
AROUND KFSD LATER IN THE MORNING. MID LEVEL MOISTURE INCREASES EAST
OF I-29...BRINGING GREATER CHANCE OF MVFR-OCCASIONAL IFR VISIBILITY
IN -SN TO SOUTHWEST MINNESOTA THIS AFTERNOON. BETTER CHANCE FOR SOME
LIGHT SNOWFALL RETURNS TO TAF SITES AFTER THIS EVENING...AS MOISTURE
WRAPS BACK INTO AREA BEHIND EXITING WAVE. GREATER AVIATION CONCERN
FOR LATTER PART OF THE PERIOD WILL BE INCREASING WINDS BEHIND THE
SYSTEM...ESPECIALLY THROUGH THE JAMES AND WESTERN MISSOURI RIVER
CORRIDOR BY VERY LATE AFTERNOON...EXPANDING EASTWARD IN THE EVENING.
SURFACE WIND GUSTS OF 25 TO 35 KNOTS LIKELY DURING THE LATER EVENING
AND OVERNIGHT.
&&
.PREV DISCUSSION.../ISSUED AT 410 AM CST/
CURRENT SATELLITE AND RADAR VERY EARLY THIS MORNING SHOWING A DRY
SLOT OVERSPREADING OUR AREA WITH THE ONLY RADAR RETURNS BEING
CONFINED TO OUR FAR NORTHEAST FROM MARSHALL TO JACKSON. IN LIGHT OF
THIS...CUT BACK A GOOD BIT ON POPS THROUGH THE MORNING HOURS WITH
PRECIPITATION REDEVELOPMENT PROBABLY NOT OCCURRING UNTIL THE UPPER
LEVEL WAVE PRESENTLY OVER EASTERN MONTANA BEGINS TO DROP
SOUTHEASTWARD...EXERTING INFLUENCE ON OUR AREA BY AFTERNOON. HAVE
HAD SOME VERY LIGHT FREEZING RAIN AND DRIZZLE OVER PORTIONS OF OUR
NORTHERN AND EASTERN AREAS OVERNIGHT...AND WITH STRATUS OOZING INTO
THE AREA FROM THE NORTHWEST CANNOT RULE OUT PATCHY FREEZING DRIZZLE
IN SOME LOCALES DURING THE MORNING. IN LIGHT OF THE ABOVE
TRENDS...READJUSTED CURRENT HEADLINES BY DROPPING THE WESTERN AND
SOUTHERN PORTIONS OF OUR ADVISORY THAT WENT THROUGH 18Z WITH LITTLE
ELSE EXPECTED...BUT KEPT THE ADVISORY OVER OUR NORTHEASTERN CWA
THOUGH EXTENDING IT 6 HOURS...12Z TO 18Z TUESDAY...WITH LIGHT SNOW
PERSISTING OVER THAT AREA INTO THAT TIME FRAME. THE PRECIPITATION
POTENTIAL WILL PICK UP IN OUR EAST BY THIS AFTERNOON INTO THIS
EVENING AS LIFT INCREASES OVER THAT AREA AS THE AFOREMENTIONED UPPER
LEVEL WAVE TRACKS ACROSS THE REGION. TEMPERATURES ALOFT WILL SUPPORT
SNOW BY THAT POINT...THOUGH AREAS ALONG THE WESTERN AND SOUTHERN
FRINGES OF THE PRECIPITATION SHIELD COULD BE MIXED WITH OR BE IN THE
FORM OF PLAIN RAIN WITH SURFACE TEMPERATURES IN THE MID AND UPPER
30S.
THE CRUX OF THE BETTER LIFT WILL BE LOCATED THROUGH OUR NORTHEASTERN
ZONES TONIGHT INTO EARLY ON TUESDAY PER UPPER LEVEL DIV Q
FIELDS...AND THIS IS WHEN MOST OF THE SNOW WILL OCCUR OVER THAT
AREA. STILL LOOKING AT 2 TO 4 INCHES OF ACCUMULATION OVER THE
ADVISORY AREA...GENERALLY IN A LINE FROM BROOKINGS TO SPENCER
EASTWARD. IN ADDITION...NORTHWESTERLY WINDS WILL PICK UP OVERNIGHT
WITH STRONG COLD AIR ADVECTION AND A TIGHTENING GRADIENT ON THE
BACKSIDE OF THE EXITING INVERTED SURFACE TROUGH. THE STRONGEST WINDS
LOOK TO BE ALONG THE MISSOURI RIVER CORRIDOR...AND KEPT THE WIND
ADVISORY...THOUGH EXPANDED SLIGHTLY...FOR THAT AREA STARTING EARLY
TONIGHT AND GOING THROUGH 18Z ON TUESDAY. WITH THE COLD AIR
ADVECTION WE WILL HAVE FALLING TEMPERATURES...THOUGH READINGS WILL
REMAIN IN CHECK WITH THE STRONG WINDS...BOTTOMING OUT IN THE UPPER
TEENS TO LOWER 20S BY EARLY TUESDAY MORNING.
FORCING AND ANY DEEPER MOISTURE PULL AWAY FROM THE AREA ON
TUESDAY...WITH SNOW DIMINISHING IN OUR EAST THROUGH THE MORNING AND
EARLY AFTERNOON HOURS. WITH DECREASING CLOUDS IN THE AFTERNOON UNDER
THE INFLUENCE OF SUBSIDENCE AS HIGH PRESSURE BUILDS INTO OUR WEST.
HIGHS LOOK TO BE IN THE 20S. THE SURFACE RIDGE AXIS SLIDES ACROSS
OUR CWA ON TUESDAY NIGHT...AND WITH DYING WINDS AND CLEARING SKIES
IT WILL BE A COLD NIGHT. LOWS WILL RANGE FROM THE LOWER SINGLE
DIGITS IN OUR NORTHEAST WHERE FRESH SNOW COVER WILL RESIDE...TO JUST
ABOVE 10 ALONG THE MISSOURI RIVER CORRIDOR.
A SOUTHERLY FLOW RETURNS TO THE REGION ON WEDNESDAY AS HIGH PRESSURE
PUSHES OFF TO THE EAST. WITH WARMING THERMAL PROFILES HIGHS WILL
APPROACH 40 IN OUR SOUTH CENTRAL SOUTH DAKOTA ZONES...TAPERING
DOWNWARD TO THE NORTH AND EAST WITH HIGHS ONLY IN THE LOWER 20S IN
OUR SOUTHWESTERN MINNESOTA AREAS WHICH WILL HAVE DEEPER SNOW COVER.
LONG RANGE THURSDAY THROUGH SUNDAY STARTS OFF WITH FAIRLY GOOD
AGREEMENT AMONG THE MODELS...SHOWING LONG WAVE RIDGE IN PLACE ACROSS
THE AREA WITH WEAK NORTHERN STREAM SHORTWAVE TOPPING THE RIDGE NORTH
OF THIS FORECAST AREA. MILD LOW LEVEL AIR IN PLACE WITH 850MB TEMPS
ABOVE 0C THROUGH FRIDAY WILL BRING TEMPERATURES CLOSER TO SEASONAL
NORMALS THAN WE HAVE SEEN OF LATE...WITH AREAS WEST OF THE JAMES
RIVER MOST LIKELY TO SEE READINGS CLIMB WELL ABOVE NORMAL THURSDAY.
CONFIDENCE DECREASES SIGNIFICANTLY IN THE LATTER PART OF THE PERIOD
AS MODELS SHOW MUCH GREATER DIVERGENCE IN HANDLING STRONG SOUTHERN
STREAM TROUGH WHICH DIGS THROUGH THE DESERT SOUTHWEST LATE THIS
WEEK. ECMWF SWINGING A CUTOFF LOW OUT INTO THE CENTRAL PLAINS NEXT
WEEKEND...WITH 04/00Z RUN STRONGER/FARTHER NORTH THAN 03/12Z RUN...
THOUGH BOTH WOULD PRODUCE A PERIOD OF SIGNIFICANT PRECIPITATION
ACROSS THIS AREA AT SOME POINT NEXT WEEKEND. OPERATIONAL GFS...ON
THE OTHER HAND...KICKS ONE PIECE OF ENERGY INTO THE PLAINS FOR
SATURDAY...BUT OTHERWISE HOLDS MAIN UPPER TROUGH OVER THE DESERT
SOUTHWEST WITH LARGELY DRY CONDITIONS FOR THE LATTER HALF OF THE
WEEKEND. GFS ENSEMBLE NOT MUCH HELP AS ITS MEAN IS MORE PROGRESSIVE
BUT MUCH FARTHER SOUTH THAN ECMWF WITH CLOSED LOW KICKING OUT INTO
THE SOUTHERN PLAINS...KEEPING PRIMARY PRECIPITATION THREAT SOUTH OF
THIS AREA. GIVEN THE DISPARITY IN SOLUTIONS AT THIS RANGE...WILL NOT
VARY MUCH OF BROAD MODEL CONSENSUS...WHICH HOLDS ONTO A SMALL CHANCE
OF PRECIP ACROSS OUR SOUTH FRIDAY NIGHT THROUGH SATURDAY NIGHT...
FOLLOWED BY SLIGHTLY GREATER CHANCES SPREADING FARTHER NORTH ACROSS
THE FORECAST AREA ON SUNDAY. TEMPERATURES WILL LIKEWISE BE HELD NEAR
CONSENSUS...WHICH IS GENERALLY ON THE COOL SIDE OF NORMAL WITH HIGHS
IN THE 30S/AROUND 40...BUT VARIANCE IN SOLUTIONS LEADS TO ADDITIONAL
CONCERNS REGARDING PRECIPITATION TYPE...AND WILL KEEP THIS RATHER
GENERIC WITH CHANCE OF RAIN OR SNOW WORDING THROUGHOUT THE PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
SDZ050-052-057>060-063>066-068>071.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR SDZ040-056.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR MNZ071-072-
080-081-089-090-097.
IA...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY FOR
IAZ031.
WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR IAZ002-003-
014.
NE...WIND ADVISORY FROM 10 PM THIS EVENING TO NOON CST TUESDAY
FOR NEZ013-014.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 AM CST MON MAR 4 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
343 AM CST MON MAR 4 2013
FORECAST FOCUS REMAINS ON WINTER STORM IMPACTING THE REGION TODAY
THROUGH TUESDAY.
LATEST WATER VAPOR IMAGERY AND RAP 500 MB ANALYSIS SHOWED A POTENT
LOW CENTERED OVER WESTERN MONTANA. A LEADING SHORTWAVE WAS MOVING
EAST ACROSS WESTERN MINNESOTA/IOWA. A BAND OF LIGHT SNOW EXTENDED
FROM WEST CENTRAL MINNESOTA...SOUTHEAST THROUGH SOUTHEAST
MINNESOTA INTO EASTERN IOWA. VISIBILITIES WITHIN THIS BAND HAD
FALLEN INTO THE 1 TO 2 MILE RANGE.
THE ONGOING BAND OF SNOW WILL CONTINUE MOVING EAST/NORTHEAST THIS
MORNING ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...APPROACHING
THE MISSISSIPPI RIVER DURING THE MID TO LATE MORNING HOURS.
MESOSCALE MODELS SHOW THE BAND REALLY FALLING APART AS IT MOVES
INTO WESTERN WISCONSIN LATE THIS MORNING INTO EARLY THIS AFTERNOON
AND REALLY NOT MAKING IT TO THE INTERSTATE 94 CORRIDOR AS IT
ENCOUNTERS VERY DRY AIR. KEAU FORECAST SOUNDINGS SHOW THE DRY AIR
EXTENDING FROM THE SURFACE THROUGH AROUND 5KFT...SO IT WILL TAKE
SOME TIME FOR SATURATION TO OCCUR. SNOW ACCUMULATIONS TODAY WILL
BE ON THE LIGHT SIDE RANGING FROM 1 TO POSSIBLY 3 INCHES OVER
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA TO AROUND AN INCH OVER FAR
WESTERN WISCONSIN. FRONTOGENESIS INCREASES...IN THE 850-700 MB
LAYER...THIS AFTERNOON RIGHT ALONG THE MISSISSIPPI RIVER. THIS
COULD KEEP LIGHT SNOWFALL INTO THE EARLY AFTERNOON HOURS BEFORE IT
WANES. GFS FORECAST SOUNDINGS THIS AFTERNOON OVER SOUTHEAST
MINNESOTA....NORTHEAST IOWA...AND FAR SOUTHWEST WISCONSIN SHOW A
LOSS OF ICE ALOFT WHICH COULD LEAD TO SOME FREEZING DRIZZLE. THE
NAM ON THE OTHER HAND KEEPS THE ICE ALOFT ACROSS THESE AREAS.
GIVEN THE CONSISTENT SIGNAL FOR A LOSS OF ICE IN THE GFS WILL
INTRODUCE A SLIGHT CHANCE OF FREEZING DRIZZLE ACROSS THESE AREAS
THIS AFTERNOON INTO EARLY THIS EVENING.
THE LOW WILL DIVE SOUTHEAST TONIGHT INTO THE UPPER MISSISSIPPI RIVER
VALLEY. VERY IMPRESSIVE LARGE SCALE FORCING ASSOCIATED WITH THE LOW
WITH DEEP QG FORCING NOTED PARTICULARLY IN THE 700-500 MB LAYER. A
BROAD AREA OF ISENTROPIC LIFT...MAINLY FOCUSED ON THE 280-310 K
SURFACES...WILL DEVELOP ACROSS THE FORECAST AREA THIS EVENING AND
CONTINUE THROUGH THE OVERNIGHT HOURS. SREF PROBABILITIES FOR SNOWFALL
RATES OF AN INCH PER HOUR DEVELOP ACROSS MOST OF THE FORECAST AREA
THIS EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS INTO TUESDAY
MORNING. OVERALL FORECAST MODELS ARE IN CLOSE AGREEMENT THIS CYCLE
PLACING A BROAD SWATH OF HEAVY SNOW ACROSS MUCH OF THE AREA WITH
ACCUMULATIONS RANGING FROM 8 TO 13 INCHES. THE HIGHEST
ACCUMULATIONS WILL BE ALONG THE MISSISSIPPI RIVER...AND INCLUDING
ALL OF SOUTHWEST WISCONSIN. DECIDED TO ISSUE A WINTER STORM
WARNING FOR CENTRAL AND NORTH CENTRAL WISCONSIN STARTING AT 6 PM
THIS EVENING AND CONTINUING THROUGH 6 PM TUESDAY. WILL CONTINUE
THE WINTER STORM WARNING FOR THE REST OF THE FORECAST AREA...BUT
PLAN ON THE BULK OF THE ACCUMULATING SNOW TO OCCUR TONIGHT THROUGH
TUESDAY MORNING. GIVEN THE FORCING OVERNIGHT INTO TUESDAY
MORNING...THE SNOW WILL BE HEAVY AT TIMES ESPECIALLY FOR THE
TUESDAY MORNING COMMUTE. THE SNOW IS EXPECTED TO TAPER OFF FROM
NORTHWEST TO SOUTHEAST LATE TUESDAY AFTERNOON AND FINALLY EXIT THE
AREA TUESDAY NIGHT. THE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA
TUESDAY AFTERNOON INTO TUESDAY EVENING WITH NORTH WINDS INCREASING
TO 10 TO 17 MPH WITH GUSTS AROUND 25 MPH POSSIBLE. WILL HAVE TO
KEEP A CLOSE WATCH ON THE POTENTIAL FOR BLOWING SNOW. ALSO...LOW
TEMPERATURES TUESDAY NIGHT COULD BE CHALLENGING WITH THE FRESH
SNOW PACK AND DECREASING CLOUDS. IF CLOUDS CLEAR EARLIER THAN
FORECAST LOWS COULD BE SEVERAL DEGREES COLDER.
HIGH PRESSURE IS EXPECTED TO BUILD INTO THE REGION ON WEDNESDAY AS
RIDGING INTENSIFIES OVER THE CENTRAL CONUS. PLAN ON PARTLY TO MOSTLY
SUNNY SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WITH HIGHS RANGING
FROM THE LOWER 30S OVER NORTHERN WISCONSIN TO THE MID 20S ACROSS
SOUTHEAST MINNESOTA.
.LONG TERM...THURSDAY THROUGH SUNDAY
343 AM CST MON MAR 4 2013
04.00 MEDIUM RANGE MODELS ARE IN AGREEMENT THURSDAY INTO FRIDAY
SHOWING RIDGING OVER THE UPPER MIDWEST. A SHORTWAVE LOOKS TO PASS
JUST NORTH OF THE AREA ACROSS NORTHERN MINNESOTA THROUGH SOUTHERN
ONTARIO. THIS FEATURE WILL BRING A SLIGHT CHANCE OF SNOW TO FAR
NORTHERN WISCONSIN AS IT MOVES THROUGH THURSDAY NIGHT. MODEL
SOLUTIONS START TO DIVERGE LATE FRIDAY THROUGH THE WEEKEND WITH THE
HANDLING OF AN UPPER LOW OVER THE DESERT SOUTHWEST. THE ECMWF TAKES
THE LOW INTO THE PLAINS ON SATURDAY...LIFTING INTO THE UPPER
MISSISSIPPI RIVER VALLEY SUNDAY INTO MONDAY. THE GFS KEEPS A CUTOFF
LOW OVER THE SOUTHWEST AND BRINGS AN OPEN WAVE ACROSS THE REGION.
GIVEN THE MODEL DIFFERENCES WILL LEAN TOWARD A MODEL CONSENSUS BLEND
THROUGH THE WEEKEND WITH PRECIPITATION CHANCES FRIDAY NIGHT THROUGH
SUNDAY. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW FORECAST
MODEL RUNS SINCE THE SOUTHWEST LOW HAS THE POTENTIAL TO BRING RAIN
AND MUCH WARMER TEMPERATURES TO THE AREA. THE ECMWF WARMS
TEMPERATURES INTO THE 50S ON MONDAY AND BRINGS NEARLY 1/2 INCH OF
RAIN INTO THE AREA. THROUGH THE WEEKEND...PLAN ON TEMPERATURES NEAR
TO SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE UPPER 30S TO AROUND 40.
&&
.AVIATION...THROUGH 18Z TUESDAY
1153 AM CST MON MAR 4 2013
A WEAKENING SNOW BAND WILL MOVE OUT OF KRST BY 04.19Z. IN THIS BAND...
THE CEILINGS ARE IN THE 1500-2500 FOOT RANGE. OUTSIDE OF THIS
BAND...CEILINGS WILL RANGE FROM 3500 TO 5000 FEET.
ANOTHER MORE SIGNIFICANT AREA OF SNOW WILL MOVE INTO SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS EVENING...AND THEN OVERSPREAD
THE ENTIRE AREA TONIGHT. THE SNOW WILL THEN CONTINUE INTO TUESDAY.
THE SNOW WILL MOVE INTO KRST BETWEEN 05.00Z AND 05.02Z...AND KLSE
BETWEEN 05.03Z AND 05.05Z. THE HEAVIEST SNOW...POSSIBLY AN INCH
AN HOUR...WILL OCCUR BETWEEN 05.09Z AND 05.18Z. ONCE THE SNOW
BEGINS CEILINGS AND VISIBILITIES WILL BECOME IFR TO MVFR. SNOW
TOTALS AT BOTH TAF SITES WILL RANGE FROM 10 TO 12 INCHES BY 06.00Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 PM CST SUN MAR 3 2013
WI...WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
WIZ032-033-041-053>055-061.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY
AFTERNOON FOR WIZ017-029-034-042>044.
MN...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR MNZ079-086-087-094-095.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
MNZ088-096.
IA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST TUESDAY
FOR IAZ008-009-018-019.
WINTER STORM WARNING FROM 6 AM MONDAY TO 6 PM CST TUESDAY FOR
IAZ010-011-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...BOYNE