Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/13/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1049 AM MDT MON MAR 11 2013
.UPDATE...
&&
.SHORT TERM...NORTHWEST FLOW ALOFT ACROSS REGION AT THIS TIME.
MOISTURE HAS INCREASED ACROSS MOUNTAINS AS OROGRAPHICS IMPROVE.
WEB CAMS SHOWING LIGHT SNOW OCCURRING ALONG CONTINENTAL DIVIDE OF
SUMMIT GRAND AND BOULDER COUNTIES AS WELL AS THE HIGHER PEAKS IN
ROCKY MOUNTAIN PARK. AIRMASS STILL FAIRLY STABLE WITH LAPSE RATES
AROUND 5 C/KM. LATEST SATELLITE SHOWING JET STREAK MOVING ACROSS
WYOMING AT THIS TIME. MOISTURE TO CONTINUE TO SPREAD INTO
MOUNTAINS THIS AFTERNOON AND EVENING WITH CONTINUED OROGRAPHICS.
LATEST RAP INDICATING LAPSE RATES IMPROVE TO AROUND 7 C/KM AS
POCKET OF MID LEVEL COOLING MOVES OVER THE AREA. WILL MAKE SOME
UPWARD ADJUSTMENTS TO POPS ACROSS MOUNTAINS THIS AFTERNOON BASED
ON CURRENT TRENDS. WILL ALSO INCREASE SNOW AMOUNTS A BIT ALONG THE
DIVIDE AND ACROSS ZONE 31 THIS AFTERNOON. ZONE 31 ON DOWNSLOPE
SIDE OF THIS NORTHWEST FLOW SO AMOUNTS WILL STILL BE LIMITED.
ACROSS PLAINS...SHOULD SEE SOME INCREASE IN MID AND HIGH LEVEL
CLOUDS AS JET APPROACHES. SHOULD SEE SOME SHOWERS DEVELOP TOWARDS
EVENING ACROSS NORTHEAST CORNER AWAY FROM DOWNSLOPE FLOW. LATEST
RAP AND HRRR SUGGESTING SOME LIGHT PRECIP IN AN AREA EAST OF A
GREELEY TO LIMON LINE AFTER 21Z...CONTINUING THROUGH THE EVENING.
WILL MAKE SOME ADJUSTMENTS LATE THIS AFTERNOON FOR THIS TREND.
SOME CONCERN FOR ANTICYCLONIC UPSLOPE DEVELOPING AS FAR WEST AS
THE DENVER AREA THIS EVENING...WHICH COULD INCREASE SNOW CHANCES
FOR DENVER. FOR NOW WILL CONTINUE WITH THE SLIGHT CHANCE FOR
DENVER. MODELS HAVE BEEN CONSISTENT WITH SOME LIGHT QPF AND SNOW
AMOUNTS THIS EVENING IN AN AREA OVER NORTHEAST WELD...MORGAN AND
WASHINGTON COUNTIES INTO THE NORTHEAST CORNER. MAY NEED TO
INCREASE POPS THERE FOR THE EVENING...FOR NOW WILL CONTINUE WITH
THE CHANCE POPS.
.AVIATION...WINDS SHIFTING TO THE NORTHWEST AS SYSTEM MOVES ACROSS
WYOMING. NORTHWEST DIRECTION TO PREVAIL THROUGH THE AFTERNOON AS
SOME MIXING STILL EXPECTED. STILL A SLIGHT CHANCE OF WINDS TURNING
NORTHEAST TOWARDS EVENING...WITH LOWERING CEILINGS AND POSSIBLE
ILS CONDITIONS. WILL CONTINUE TAF TRENDS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 442 AM MDT MON MAR 11 2013/
SHORT TERM...A JET STREAK WILL DROP ACROSS NORTHEAST COLORADO
TONIGHT. CURRENT MOUNTAIN WAVE WILL DIMINISH AS THE STABILITY
STRUCTURE GOES AWAY. THERE IS A BRIEF DECREASE IN HIGH
CLOUDS...THEN THEY SHOULD COME BACK THIS AFTERNOON. AREA OF LIFT
WILL SLIDE ACROSS THE NORTHEAST CORNER OF THE STATE OVERNIGHT. NOT
THAT IMPRESSED WITH WHAT IS HAPPENING UPSTREAM...AS AREAS UNDER
THE LIFT NOW HAVE FAIRLY HIGH CEILINGS AND NOT MUCH PRECIPITATION.
BUT THERE WILL BE SOME INSTABILITY UNDER THIS AREA AND THE LIFT IS
REAL. MODELS ALL SHOW A BAND WITH SEVERAL INCHES OF SNOW THROUGH
STERLING AND AKRON OVERNIGHT. AMOUNTS SEEM A BIT MUCH GIVEN THE
MOISTURE AVAILABLE...BUT I WILL RAISE POPS IN THIS AREA. WITH A
WESTERLY COMPONENT OFF THE GROUND...I WILL KEEP THE POPS AWAY FROM
THE FRONT RANGE...WE WILL PROBABLY DEVELOP AN ANTICYCLONE WITH THE
SHOWERS ON THE NORTHEAST SIDE OF THE LOW LEVEL SHEAR ZONE...SO
PROBABLY NOT MUCH CHANCE FROM FORT COLLINS-DIA AND WESTWARD. FOR
THE MOUNTAINS INCREASING MOISTURE AT OR BELOW MOUNTAINTOP LEVEL
THIS AFTERNOON...WE SHOULD SEE SOME OROGRAPHIC SNOW THOUGH IT WILL
NOT BE AS UNSTABLE AS WILL BE OVER THE PLAINS. NAM SNOWFALL OF UP
TO 4 INCHES IS PROBABLY A BIT MUCH...BUT HERE TOO I WILL RAISE
POPS FOR LIGHT SNOW. DROPPED LOW TEMPERATURES A BIT TONIGHT IN
LINE WITH THE LATEST GUIDANCE.
LONG TERM...FAIRLY STRONG NORTHWESTERLY FLOW ALOFT IS PROGGED
FOR THE CWA TUESDAY THROUGH WEDNESDAY...DECREASING IN SPEED A BIT
BY WEDNESDAY NIGHT BUT STILL TO STAY NORTHWESTERLY. MODELS KEEP AN
UPPER RIDGE OVER THE WESTERN U.S. THROUGH THE PERIOD. THE SYNOPTIC
SCALE ENERGY IS VERY WEAK AND DOWNWARD IN NATURE TUESDAY THROUGH
WEDNESDAY NIGHT. THE BOUNDARY LAYER FLOW WILL MAINLY ADHERE TO
NORMAL DIURNAL PATTERNS THROUGH THE PERIOD. CONCERNING
MOISTURE...THERE IS SOME PROGGED IN THE LOWER LEVELS ON TUESDAY.
BY TUESDAY NIGHT...MOISTURE DECREASES OVER THE EASTERN HALF OF THE
CWA...WITH SOME LINGERING OVER THE MOUNTAINS. WEDNESDAY AND
WEDNESDAY NIGHT ARE PRETTY DRY. THE QPF FIELDS HAVE A TAD OF
MEASURABLE SNOW OVER THE HIGH MOUNTAINS TUESDAY MORNING...THEN
THERE IS NOTHING ANYWHERE THROUGH WEDNESDAY NIGHT. WILL KEEP MINOR
POPS GOING IN THE HIGH MOUNTAINS TUESDAY INTO TUESDAY
EVENING...THATS IT. FOR TEMPERATURES...TUESDAY`S HIGHS DO NOT LOOK
AS WARM AS THEY DID FROM YESTERDAY`S 00Z MODEL RUNS. THEY ARE NOW
0-2 C COOLER THAN TODAY`S EXPECTED READINGS. WEDNESDAY`S HIGHS ARE
3-8 C WARMER THAN TUESDAY`S HIGHS. FOR THE LATER DAYS...THURSDAY
THROUGH SUNDAY...THE UPPER RIDGE IS PROGGED TO SLOWLY MAKE ITS WAY
EAST GETTING OVER COLORADO ON FRIDAY. THE ECMWF STILL SHOWS A WEAK
UPPER TROUGH TO MOVE INTO THE CWA...BUT NOW IT MOVE ACROSS LATE
SATURDAY INTO SATURDAY NIGHT AND IT IS WEAKER THAN YESTERDAY`S RUN
INDICATED. WILL INCREASE CLOUDINESS A BIT SATURDAY AND SUNDAY...
BUT NO POPS FOR THE LAST FOUR DAYS ANYWHERE. TEMPERATURES LOOK TO
BE ABOVE SEASONAL NORMALS ALL FOUR DAYS.
AVIATION...VFR CONDITIONS TODAY. NORTH TO NORTHWEST WINDS SHOULD
MIX DOWN BY EARLY AFTERNOON...TURNING NE OR POSSIBLY SE BY EARLY
EVENING. CEILINGS MAY LOWER ENOUGH TO REQUIRE INSTRUMENT
APPROACHES TO KDEN OVERNIGHT...THOUGH THERE IS ONLY A SLIGHT
CHANCE OF SNOW SHOWERS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
649 PM EDT MON MAR 11 2013
...SHALLOW COASTAL FLOODING AROUND HIGH TIDE THIS EVENING ALONG
THE LOWER SOUTH CAROLINA COAST...
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE THROUGH THE EVENING. A COLD FRONT
WILL ADVANCE INTO CENTRAL GEORGIA AND THE CAROLINAS TONIGHT. THE
FRONT WILL MOVE OFF THE COAST TUESDAY MORNING FOLLOWED BY HIGH
PRESSURE THROUGH SATURDAY. A WEAK BACKDOOR COLD FRONT MAY APPROACH
FROM THE NORTH ON SUNDAY AND POSSIBLY LINGER IN THE AREA INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN MICHIGAN WILL
WEAKEN TONIGHT AS IT MOVES NORTH INTO SOUTHERN QUEBEC AND
SOUTHEAST ONTARIO. THE ATTENDANT COLD FRONT STRETCHES FROM SURFACE
LOW PRESSURE NEAR SOUTHERN LAKE MICHIGAN SOUTH THROUGH THE OHIO
AND TENNESSEE VALLEYS AND INTO THE CENTRAL GULF OF MEXICO. THE
FRONT WILL STEADILY MARCH EAST AND POSITIONED BE VERY NEAR THE
COAST BY SUNRISE TUESDAY. GOES-EAST WATER VAPOR IMAGERY SHOWS A
LARGE PLUME OF TROPICAL MOISTURE SURGING NORTH ACROSS MUCH OF THE
EASTERN U.S. WITH BLENDED AMSU/SSMI DATA PINGING PWATS IN EXCESS
OF 1.50 INCHES ACROSS SOUTHERN ALABAMA AND GEORGIA. THESE VALUES
WILL ADVECT EAST INTO SOUTHERN SOUTH CAROLINA AND SOUTHEAST
GEORGIA BY MIDNIGHT AS PRE-FRONTAL LOW-LEVEL JETTING STRENGTHENS.
RAIN CHANCES WILL STEADILY INCREASE FROM WEST-EAST OVERNIGHT AS
THE COLD FRONT DRAWS CLOSER AND SHORTWAVE ENERGY CURRENTLY MOVING
ACROSS THE SOUTHERN MISSISSIPPI VALLEY EJECTS NORTHEAST ACROSS
NORTHERN GEORGIA AND THE SOUTHERN APPALACHIANS. WILL INCREASE POPS
TO 100 PERCENT FOR ALL AREAS TONIGHT WITH THE BULK OF THE HEAVIEST
RAINS LIKELY FALLING BETWEEN MIDNIGHT AND SUNRISE...POSSIBLY A BIT
EARLIER ACROSS FAR INTERIOR SOUTHEAST GEORGIA. GENERALLY USED A
BLEND OF THE HIGHER RESOLUTION H3R AND RAP RUNS TO CONSTRUCT
HOURLY WEATHER PARAMETERS THROUGH 6 AM. AVERAGE RAIN AMOUNTS OF
0.25-0.75 INCH LOOKS REASONABLE WITH LOCALLY HIGHER VALUES LIKELY.
HOURLY TEMPERATURES WILL BE A BIT ATYPICAL WITH THE AREA HOLDING
WELL INTO THE WARM SECTOR UNTIL EARLY TUESDAY MORNING. LOWS WILL
RANGE FROM THE MID 50S ACROSS FAR INTERIOR SOUTHEAST GEORGIA TO
THE LOWER 60S AT THE COAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...THERE ARE SOME SLIGHT TIMING DIFFERENCES REGARDING THE
COLD FRONTAL PASSAGE IN THE LATEST 12Z NUMERICAL MODEL
SOLUTIONS...YET EVEN THE SLOWEST SCENARIOS HAVE THE FRONT
OFFSHORE BY MID TO LATE MORNING. WILL THUS CONTINUE TO ADVERTISE
70 TO 80 PERCENT RAIN CHANCES GENERALLY ALONG AND EAST OF
INTERSTATE 95 AT DAYBREAK...WITH POPS 50 PERCENT AND LOWER JUST TO
THE WEST. PRECIPITATION POTENTIAL WILL RAPIDLY DIMINISH BEHIND
THE FRONT AS THE MORNING PROGRESSES...AND HAVE INDICATED ONLY
SLIGHT CHANCES REMAINING FOR THE CHARLESTON TRI COUNTY AREA BY MID
AFTERNOON. TEMPERATURES WILL ONLY BE A FEW DEGREES COOLER THAN
MONDAY...PEAKING FROM 70 TO 72 DEGREES...A COMBINED RESULT OF
DELAYED COLD ADVECTION BEHIND THE FRONT AND THE WARMING EFFECTS OF
INCREASING SUNSHINE AND DOWNSLOPE FLOW. MINIMUM TEMPERATURES
TUESDAY NIGHT WILL REFLECT THE COOLING TREND...FALLING MORE THAN
10 DEGREES LOWER THAN THE PREVIOUS NIGHT...INTO THE 40 DEGREE
RANGE.
WEDNESDAY AND THURSDAY...THE AXIS OF A SHORTWAVE TROUGH WILL SWING
ACROSS THE EAST COAST WEDNESDAY AFTERNOON...AS CENTRAL CANADIAN
HIGH PRESSURE BUILDS INTO THE REGION THROUGH THE LATE WEEK PERIOD.
STRONG COLD ADVECTION WILL INITIATE ACCORDINGLY...AND WHEN COMBINED
WITH LOWERING HEIGHTS ALOFT...WILL SUPPRESS HIGH TEMPERATURES IN
THE MID TO UPPER 60S WEDNESDAY AFTERNOON. BREEZY CONDITIONS ARE
ALSO EXPECTED DURING THE DAYTIME HOURS ON WEDNESDAY...AS DECENT
DIURNAL MIXING TAPS INTO 30 KT BOUNDARY LAYER WINDS. HIGH
TEMPERATURES WILL ACTUALLY BE A DEGREE OR TWO LOWER ON
THURSDAY...WITH WINDS VEERING TOWARD THE NORTH AND DOWNSLOPE
WARMING EFFECTS DIMINISHING. ABUNDANT SUNSHINE AND DRY CONDITIONS
WILL PREVAIL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BROAD UPPER RIDGE WILL SPREAD EAST THURSDAY NIGHT THROUGH
SATURDAY...SUPPORTING A WARMING TREND AND DRY WEATHER.
TEMPERATURES WILL BE BACK INTO THE 70S BY SATURDAY GIVEN CURRENT
TRENDS. UNCERTAINTY INCREASES SUNDAY INTO MONDAY CONSIDERING SOME
DISCREPANCIES IN MEDIUM RANGE MODEL SOLUTIONS. THE LATEST ECMWF IS
STILL SHOWING A PRONOUNCED UPPER TROUGH DIGGING INTO THE CENTRAL
UNITED STATES ON MONDAY...WITH THE 12Z GFS COMING MORE INTO LINE
WITH THIS SCENARIO. HAVE MAINTAINED A DRY EXTENDED FORECAST WITH
ABOVE NORMAL TEMPERATURES...WHILE SHOWING AN INCREASE IN CLOUD
COVER TO ACCOUNT FOR A MORE UNSETTLED PATTERN TOWARD THE END OF
THE PERIOD.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
TO BE ISSUED SHORTLY.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE AT THIS TIME.
&&
.MARINE...
TONIGHT...LATEST SWAN AND WW4 OUTPUT SUGGEST 6 FT SEAS WILL AFFECT
THE GEORGIA NEARSHORE WATERS LATER TONIGHT THROUGH TUESDAY
MORNING. EXPANDED THE SMALL CRAFT ADVISORY INTO THIS AREA GIVEN
THIS LATEST MODEL TREND.
WINDS/SEAS WILL THEN INCREASE/BUILD OVER ALL WATERS TONIGHT AS
LOW LVL WINDS ENHANCE OVER THE WATERS AND THE COLD FRONT
APPROACHES THE COAST LATE. SOUTHERLY FLOW INCREASING TO 15-20 WITH
GUSTS TO 25 KT IS FORECAST TO BUILD SEAS TO 4-6 FT WITHIN 20 NM
AND 5-8 FT 20-60 NM OFFSHORE. A SMALL CRAFT ADVISORY WILL
THEREFORE REMAIN IN EFFECT FOR MARINE LEGS WITH THE EXCEPTION OF
THE CHARLESTON HARBOR.
WINDS AND SEAS FOR THE NEARSHORE WATERS WILL DIMINISH BELOW
ADVISORY CRITERIA NO LATER THAN TUESDAY AFTERNOON AS THE COLD
FRONT PUSHES OFFSHORE...WHILE SEAS MAINTAIN ADVISORY CONDITIONS
ACROSS THE OUTER GEORGIA WATERS. COLD ADVECTION WILL BE SLIGHTLY
DELAYED BEHIND THE FRONT...WITH THE MAIN SURGE EXPECTED MORE
TOWARD WEDNESDAY. THE DEEPEST MIXING WILL BE ACROSS THE WARMER
OFFSHORE WATERS...MAINLY BEYOND 20 NM FROM THE COAST. THUS THE
OUTER GEORGIA MARINE ZONES WILL REMAIN UNDER A SMALL CRAFT
ADVISORY THROUGH THURSDAY. FREQUENT GUSTS UP TO 25 KT ACROSS
PORTIONS OF THE NEARSHORE WATERS COULD NECESSITATE ADVISORIES FOR
THOSE AREAS AS WELL. MUCH WEAKER FLOW EXPECTED THURSDAY INTO THE
WEEKEND AS HIGH PRESSURE BUILDS FROM THE WEST/NORTHWEST.
&&
.TIDES/COASTAL FLOODING...
TIDES ANOMALIES ARE RUNNING 1 FT ABOVE PREDICTED IN THE CHARLESTON
HARBOR EARLY THIS EVENING. CURRENT TRENDS SUGGEST TIDE LEVELS WILL
PEAK VERY NEAR 7.0 FT MLLW WITH HIGH TIDE THIS EVENING. THE
SITUATION LOOKS MARGINAL...BUT GIVEN THE AMOUNT OF TIDAL LOADING
THAT HAS OCCURRED OVER THE PAST SEVERAL HIGH TIDES...WILL HOIST A
COASTAL FLOOD ADVISORY FOR THE SOUTH CAROLINA COASTAL
ZONES...EXCLUDING TIDAL BERKELEY...FROM 8 PM UNTIL 11 PM.
HIGH TIDE WILL OCCUR IN THE CHARLESTON HARBOR AT 844 PM AND IN THE
BEAUFORT RIVER AT BEAUFORT AT 959 PM.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR AMZ350-352.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THURSDAY FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 PM EDT MON MAR 11 2013
.AVIATION...
VARIABLE CIGS IMPACTED KSBN FOR A SHORT PERIOD OF TIME IN THE WAKE
OF THE FRONTAL BOUNDARY SWEEPING ACROSS THIS MORNING. LOW CLOUDS
ASSOCIATED WITH THE UPPER LOW ITSELF WERE DRIFTING BACK IN FROM
ILLINOIS AND WILL CAUSE A RETURN TO LOW END MVFR CONDITIONS WITH
SOME EXCURSIONS TO IFR POSSIBLE TONIGHT. AT KFWA TAFS HAVE BEEN
ADJUSTED TO REFLECT THE TEMP IMPROVEMENT IN FLGT CONDITIONS BEFORE
RETURNING LATER THIS AFTERNOON. NO FURTHER DETAIL ADDED BEYOND
00-02Z WITH PERSISTENT CAA AND LOW CLOUDS WITH UPPER LOW LINGERING
ACROSS THE AREA THROUGH THE REMAINDER OF THE PERIOD.
&&
.UPDATE...
SECOND UPDATE OF THE DAY ISSUED TO ADJUST FOR RADAR TRENDS AS
RETURNS CONTINUE TO INCREASE AHEAD OF AND JUST BEHIND FAST MOVING
FRONT. HRRR FOR PAST FEW HOURS HAS HINTED AT A BIT OF A FINE LINE
OF COVECTION POSSIBLY DEVELOPING AND RECENT TREDNS SUGGEST THIS
MAY BE UNDERWAY NEAR THE IN/OH STATE LINE AS SFC DWPTS APPROACH 50
DEGREES. ONE STRAY LIGHTNING STRIKE WAS DETECTED NOT TO LONG AGO
EAST OF AUBURN INDIANA. WHILE THERE MAY ONLY BE ONE OR 2 MORE
STRIKES PRIOR TO DEPARTURE FROM THE AREA OPTED TO ADD SLGT CHC
MENTION TO ZONES/GRIDS FOR A FEW HOURS. OTHERWISE PRECIP WILL COME
TO AND END FROM SW TO NE THROUGH THE AFTERNOON WITH GENERALLY DRY
CONDTIONS ALREADY SEEN ALONG AND WEST OF US 31. TEMPS WILL FALL
OFF AS THE RAIN CLEARS WITH READINGS DROPPING INTO THE 30S.
HOWEVER...ANY MIX OR SWITCH TO SNOW STILL LOOKS TO OCCUR CLOSER
TO/AFTER 00Z. WILL ADDRESS IN REGULAR FORECAST PACKAGE.
&&
.PREV DISCUSSION... /ISSUED 433 AM EDT MON MAR 11 2013/
SHORT TERM...
DEEP LYRD CYCLONE OVR CNTRL IA WILL LIFT OUT THROUGH NRN LWR MI
TONIGHT AS SFC FNTL ZONE SHIFTS EWD ACRS CWA TDA. RAINFALL IN
ASSOCN/W THIS SYS HAS LARGELY BEEN A BUST SO FAR TIED TO POOR EWD
MOISTENING AS PLAINLY ILLUSTRATED IN 00Z RAOBS FM ILN/DTX. HWVR
W/SFC BNDRY STILL PLANTED THROUGH CNTRL IL AND CONTD WARM SECTOR LL
MSTR FLUX -SHRA WOULD STILL APPEAR TO BE A GOOD PROSPECT THROUGH
EARLY AFTN TIED TO NEARING SFC FNTL ZONE AND ASSOCD LL SATURATED
ASCENT. OTRWS WELL DVLPD WRAP AROUND DEFORMATION ZONE ACRS WRN IA
LOOKS TO CARRY EWD AND GRAZE MUCH OF THE AREA LT THIS AFTN/EARLY
THIS EVENING W/A PD OF LT SNOW SHOWERS...TIMED W/INTENSIFYING LL
THERMAL TROUGHING. HWVR MARGINAL VERTICAL ASCENT/SFC TEMPS SHLD
YIELD LTL TO NO SNOW ACCUMULATION THIS EVENING.
SECONDARY FOLLOWING UPR DISTURBANCE DROPPING WWD THROUGH BASE OF
LARGER SCALE TROUGH POSITIONED THROUGH THE WRN LAKES ON TUE SHLD
YIELD ENHANCED DIURNAL SHSN TUE AFTN/EVE AND WILL BACK/EXPAND PRIOR
POPS QUITE A BIT IN CONCERT W/EVEN STRONGER/DEEPER LL THERMAL
TROUGHING AND UNDER GUISE OF STEEP LL LAPSE RATES DVLPG IN MOIST
CYCLONIC FLW.
DIFFICULT NR TERM TEMP FCST GIVEN WWD POSITION OF SFC CDFNT THIS
MORNING. WILL GENERALLY FOLLOW CLOSE KNIT MOS BLEND WHICH YIELDS A
PREFERRED NON-DIURNAL CURVE WRN HALF AND FLAT LINES ERN HALF. MUCH
COLDER AIR TO FILTER IN OVERNIGHT AND AGAIN LT TUE.
LONG TERM...
WEDNESDAY THROUGH SUNDAY...VERY COLD AIR WILL BE OVER THE FORECAST
AREA WEDNESDAY WITH THE LIKELIHOOD OF A WEAK SHORT WAVE TROF MOVING
ACROSS THE WESTERN GREAT LAKES REGION. HAVE ADDED A CHANCE FOR SNOW
SHOWERS MOST AREAS WEDNESDAY GIVEN SHALLOW BUT STEEP LAPSE RATES
EXPECTED WITH RESIDUAL MOISTURE FROM RECENT SNOWMELT AND LIGHT
PRECIPITATION IN CONJUNCTION WITH DAYTIME HEATING. EXPECT ALSO SOME
LAKE ENHANCEMENT UPSTREAM WITH FAVORABLE PRECONDITIONING OF THE LOW
LEVELS. AFTER WEDNESDAY...A ECMWF/GFS CONSENSUS FAVORS THE FLOW
BECOMING HIGH ZONAL LATE IN THE WEEK WITH MODERATING TEMPERATURES...
SO CONTINUED TO TREND HIGHS WARMER FRIDAY. HOWEVER...CONFIDENCE
BECOMES VERY POOR BY SUNDAY AS REFLECTED IN THE GFS MEX MODEL OUTPUT
WITH VERY HIGH STANDARD DEVIATIONS...THUS...TRIED TO KEEP
PERSISTENCE FOR THE 2ND HALF OF THIS PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT
WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
313 PM MDT MON MAR 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 PM MDT MON MAR 11 2013
FORECAST CONCERN IN THE LONG TERM PERIOD IS THE POSSIBILITY OF
PRECIPITATION THIS WEEKEND.
THE AXIS OF THE BROAD UPPER RIDGE TRANSLATES FROM THE WEST COAST
TO THE INTERMOUNTAIN AND ROCKY MOUNTAIN REGION BETWEEN TUESDAY
NIGHT AND THURSDAY NIGHT. BY FRIDAY THE RIDGE BEGINS TO FLATTEN AS
SEVERAL SHORT WAVE TROUGH BEGIN TO RIDE UP OVER THE APEX OF THE
RIDGE. THESE WAVES ARE EXPECTED TO REMAIN NORTH OF THE CENTRAL
HIGH PLAINS REGION THROUGH AT LEAST SATURDAY MORNING.
THEREFORE...THE FORECAST AREA IS EXPECTED TO REMAIN DRY AND WARM
THROUGH SATURDAY NIGHT WITH A PERSISTENT LEE TROUGH REMAINING IN
PLACE IN THE VICINITY OF THE EASTERN COLORADO BORDER AREA.
EARLY SATURDAY...IT APPEARS THAT A COOLER AREA OF HIGH PRESSURE
WILL MOVE SOUTHWARD ACROSS THE PLAINS STATES WITH A BACKDOOR COLD
FRONT PUSHING INITIALLY INTO THE EASTERN PORTION OF THE FORECAST
AREA WITH COOLER AIR REMAINING GENERALLY IN PLACE ACROSS THE
PLAINS THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF
NEXT WEEK. THE GFS AND ECMWF ARE NO LONGER COMPLETELY OUT OF PHASE
WITH EACH OTHER AT THIS POINT...BUT CONTINUE TO OFFER SOMEWHAT
DIFFERENT SOLUTIONS WITH THE NEXT UPPER TROUGH ENTERING THE
PACIFIC NORTHWEST AND TRACKING EAST OF THE ROCKIES SOMETIME IN THE
SUNDAY TO SUNDAY NIGHT TIME FRAME. WITH SEVERAL SMALLER SHORT WAVE
TROUGHS PRECEDING THE MAIN UPPER TROUGH AND WITH THE APPROACH AND
PASSAGE OF THE MAIN UPPER TROUGH...EXPECT AT LEAST A SLIGHT CHANCE
OF PRECIPITATION OVER THE FORECAST AREA FROM LATE SATURDAY THROUGH
AT LEAST SUNDAY NIGHT AND POSSIBLY THE DAY ON MONDAY...DEPENDING
UPON THE MODEL SOLUTION THAT ENDS UP CLOSER TO REALITY. HAVE
THEREFORE GONE WITH A FAIRLY BROAD BRUSHED SOLUTION THROUGH THE
WEEKEND AND INTO MONDAY WITH A SLIGHT CHANCE OF LIGHT RAIN WITH
LIGHT ACCUMULATIONS DURING THAT TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1134 AM MDT MON MAR 11 2013
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS EVENING AT BOTH
TERMINALS. MVFR CONDITIONS WILL DEVELOP OVER KGLD AT A BAND OF
RAIN/SNOW DEVELOPS LATE THIS AFTERNOON AND EVENING OVER EASTERN
COLORADO AND SPREADS INTO NORTHWEST KANSAS AS ALL SNOW TONIGHT. I
COULDNT RULE OUT BRIEF IFR CONDITIONS ALONG MOST INTENSE PART OF
SNOW BAND TONIGHT...HOWEVER I WAS NOT CONFIDENT ENOUGH TO PREVAIL
OR INCLUDE TEMPO GROUP...SINCE LOCATION OF THIS BAND IS STILL IN
QUESTION. CHANCE ARE LOWER FOR PRECIP/MVFR AT AT THE KMCK
TERMINAL SO CURRENTLY HAVE VFR CONTINUING WITH VCSH. VFR
CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS AFTER 12Z WHEN PRECIP
QUICKLY MOVES EAST.
WINDS HAVE BEEN SLOWER TO INCREASE AT BOTH TERMINALS TODAY WITH
THICK HIGH CLOUDS OVERHEAD.I STILL EXPECT WIND GUSTS AROUND 20KT
BY MID AFTERNOON...DECREASING AROUND SUNSET. GUSTY WEST WINDS
SHOULD REDEVELOP AROUND 15Z TUESDAY WITH CLEARING SKIES AND BETTER
DAYTIME MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1215 PM MDT MON MAR 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 224 AM MDT MON MAR 11 2013
IN THE EXTENDED (THUR-SUN)...MEDIUM RANGE MODELS BEGIN THE PERIOD IN
REASONABLE AGREEMENT WITH LARGE RIDGE CENTERED OVER THE
INTERMOUNTAIN WEST...BUT FAIRLY QUICKLY BECOME OUT OF PHASE WITH
EACH OTHER OVER THE WEEKEND LEADING TO A FAIRLY LOW CONFIDENCE
FORECAST FOR THE AREA. WHILE THERE DOES APPEAR TO BE SOME THREAT FOR
PRECIPITATION IN THE SATURDAY-SUNDAY PERIOD...POSSIBILITY STRETCHES
FOR SEVERAL PERIODS DUE TO DIFFERENCES IN MODEL TIMING/OVERALL
PATTERN. GIVEN OVERALL CONFIDENCE LOW...THINK TRYING TO PICK AN
SPECIFIC PERIOD TO ENHANCE POPS NOT WARRANTED ATTM AND WILL CONTINUE
DRY FORECAST FOR CWA.
FOR TEMPERATURES...CONFIDENCE REMAINS HIGH THAT TEMPERATURES WILL
WARM INTO THE 70S THROUGH FRIDAY BUT WITH AFOREMENTIONED
CONCERNS...THINK KEEPING TEMPS AROUND CONSENSUS VALUES WARRANTED FOR
REST OF PERIOD DUE TO UNCERTAINTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1134 AM MDT MON MAR 11 2013
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS EVENING AT BOTH
TERMINALS. MVFR CONDITIONS WILL DEVELOP OVER KGLD AT A BAND OF
RAIN/SNOW DEVELOPS LATE THIS AFTERNOON AND EVENING OVER EASTERN
COLORADO AND SPREADS INTO NORTHWEST KANSAS AS ALL SNOW TONIGHT. I
COULDNT RULE OUT BRIEF IFR CONDITIONS ALONG MOST INTENSE PART OF
SNOW BAND TONIGHT...HOWEVER I WAS NOT CONFIDENT ENOUGH TO PREVAIL
OR INCLUDE TEMPO GROUP...SINCE LOCATION OF THIS BAND IS STILL IN
QUESTION. CHANCE ARE LOWER FOR PRECIP/MVFR AT AT THE KMCK
TERMINAL SO CURRENTLY HAVE VFR CONTINUING WITH VCSH. VFR
CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS AFTER 12Z WHEN PRECIP
QUICKLY MOVES EAST.
WINDS HAVE BEEN SLOWER TO INCREASE AT BOTH TERMINALS TODAY WITH
THICK HIGH CLOUDS OVERHEAD.I STILL EXPECT WIND GUSTS AROUND 20KT
BY MID AFTERNOON...DECREASING AROUND SUNSET. GUSTY WEST WINDS
SHOULD REDEVELOP AROUND 15Z TUESDAY WITH CLEARING SKIES AND BETTER
DAYTIME MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1112 PM MDT SUN MAR 10 2013
.UPDATE...
ISSUED AT 540 PM MDT SUN MAR 10 2013
WINDS HAD DECREASED TO BELOW ADVISORY CRITERIA SO WIND ADVISORY
HAS BEEN CANCELLED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LONG WAVE TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE THE CENTRAL PLAINS WITH BASE
OF TROUGH OVER BAJA PENINSULA. STACKED H7/H5 CLOSED LOW CENTER IS
CURRENTLY OVER NE KANSAS WITH SHORTWAVE RIDGE BUILDING ACROSS
WESTERN US INTO THE NORTHERN PLAINS ON THE BACK SIDE OF THIS SYSTEM.
BETWEEN THE RIDGE AND CLOSED LOW A STRONG AXIS OF SUBSIDENCE IN IN
PLACE ACROSS OUR CWA. TIGHT PRESSURE GRADIENT IS CURRENTLY IN PLACE
ACROSS THE EASTERN HALF OF THE CWA WITH HIGH PRESSURE BUILDING OVER
EASTERN COLORADO AND STRONG SURFACE LOW PRESSURE CENTERED OVER
MISSOURI.
GRADIENT WILL CONTINUE TO WEAKEN AS LARGE SCALE SYSTEM PULLS EAST
THIS AFTERNOON AND HIGH PRESSURE CONTINUES TO BUILD OVER THE CWA. WE
ARE ALREADY SEEING WINDS DECREASE BELOW ADVISORY CRITERIA OVER THE
NW HALF OF THE CWA. WINDS CONTINUE TO HOVER RIGHT AT OR ABOVE
ADVISORY CRITERIA WITH BETTER THAN ANTICIPATED AFTERNOON MIXING
ACROSS THE SE HALF OF THE AREA. I DECIDED TO EXTEND ADVISORY
00Z...THOUGH WE MIGHT BE ABLE TO EXPIRE THE ADVISORY EARLY
ESPECIALLY FOR THE NW COUNTIES.
WINDS WILL DECREASE RAPIDLY AROUND SUNSET WITH LIGHT W/NW WINDS
EXPECTED OVERNIGHT TONIGHT. WITH SHORTWAVE RIDGE BUILDING EAST FLOW
ALOFT WITH SHIFT TO A NW WITH LEE TROUGH BEGINNING TO REDEVELOP OVER
EASTERN COLORADO BY 12Z TONIGHT. EARLY THIS AFTERNOON EASTERN
LOCATIONS COULD STILL SEE A FEW FLURRIES AS ENERGY ROTATES ON THE
BACK SIDE OF UPPER LOW...HOWEVER BEYOND THIS THE FORECAST SHOULD
REMAIN DRY THROUGH THE DAYTIME PERIOD MONDAY.
THERE WILL BE A MODERATION OF THE AIR MASS OVER OUR CWA FROM THE
WEST TO THE EAST TONIGHT WHICH WILL CONTINUE THROUGH THE DAY
MONDAY. IT IS DIFFICULT TO TELL WHAT IMPACT RECENT SNOW PACK WILL
HAVE ON TEMPS TONIGHT AND MONDAY WITH PAST EVENTS WARMING MUCH
FASTER THAN ORIGINALLY INDICATED. FOR NOW I THINK OUR LOWS SHOULD
COOL TO LOW TO MID TEENS FOR MOST LOCATIONS DESPITE WARMING
AIRMASS. H85 TEMPS ON MON WOULD SUPPORT HIGHS IN THE MID 50S TO
AROUND 60F UNDER IDEAL MIXING. TO ACCOUNT FOR SNOW I KEPT HIGH
FORECAST MON ABOUT 5-10F COOLER RANGING FROM UPPER 40S IN THE
NORTH TO MID 50S IN THE SOUTH WHERE LESS SNOW FELL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LONG TERM FORECAST CONCERNS ARE THE POTENTIAL FOR FLURRIES MONDAY
NIGHT AND THE POSSIBILITY OF PRECIPITATION DURING NEXT
WEEKEND.
NORTHWEST FLOW ALOFT OVER THE FORECAST AREA AS THE RIDGE AMPLIFIES
OVER THE WESTERN UNITED STATES WILL CARRY A SHORT WAVE TROUGH
THROUGH THE CENTRAL HIGH PLAINS REGION OVERNIGHT MONDAY NIGHT.
THERE MAY BE A FEW FLURRIES ASSOCIATED WITH THIS WAVE AS MID AND
LOWER LEVEL MOISTURE INCREASES. WINDS MAY ALSO BE GUSTY OVERNIGHT
AND INTO THE DAY ON TUESDAY AS SUBSIDENCE BEHIND THIS WEAK WAVE
HELPS MIX STRONGER WINDS TO THE SURFACE.
DRY CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WORK WEEK
AS THE BROAD RIDGE OVER THE WESTERN UNITED STATES MOVES EASTWARD
FROM THE INTERMOUNTAIN REGION TO THE ROCKIES AND HIGH PLAINS. THE
RIDGE WILL BEGIN TO FLATTEN THURSDAY NIGHT AND FRIDAY AS A SERIES
OF WEAKER SHORT WAVE TROUGHS BEGINS TO MOVE INTO THE WEST COAST
AND ACROSS THE TOP OF THE RIDGE. MUCH WARMER THAN NORMAL
TEMPERATURES ARE EXPECTED ACROSS THE FORECAST AREA THURSDAY AND
FRIDAY.
THE FLOW FLATTENS ACROSS THE UNITED STATES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND FOR A MORE PROGRESSIVE PATTERN. BETWEEN
FRIDAY NIGHT AND SUNDAY THE GFS AND ECMWF BEGIN TO DIVERGE IN
THERE INDIVIDUAL HANDLING OF SUBSEQUENT SHORT WAVES AND THE LARGER
SCALE UPPER TROUGH MOVING INTO THE WESTERN UNITED STATES.
DEPENDING UPON WHICH SOLUTION PANS OUT...THE CENTRAL HIGH PLAINS
REGION COULD SEE COOLER TEMPERATURES...ALTHOUGH STILL WARMER THAN
AVERAGE FOR THIS TIME OF YEAR...ALONG WITH SOME LIGHT SHOWERS
MOVING ACROSS THE AREA ON SATURDAY...OR COOLER TEMPERATURES AND A
FEW SPRINKLES ACROSS PORTIONS OF THE AREA ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1109 PM MDT SUN MAR 10 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. AFTER THE SUN
COMES THE WINDS WILL BECOME NORTHWEST AND GUSTY AS A SURFACE
TROUGH MOVES THROUGH THE AREA. WINDS WILL BECOME MUCH LIGHTER NEAR
00Z. EVEN THOUGH CONDITIONS WILL REMAIN VFR...CEILINGS WILL LOWER
AND THICKEN. TOWARD THE END OF THIS PERIOD OR JUST AFTER...THERE
WILL BE THE POSSIBILITY OF VERY LIGHT SNOW. SINCE IT IS AT THE END
OF THIS PERIOD...CHOSE NOT TOO MENTION IT AT THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 AM EDT MON MAR 11 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1005 PM EST Sun Mar 10 2013
Rain band is progressing slowly eastward across the western forecast
area. Dewpoints have been slow to come up over the eastern half, but
that should change as this batch of moisture aloft saturates the
lower levels. Expect the rain shield to expand as we get a low level
surge of winds overnight. Latest RAP indicating between 45-55 knots
at 2 kft. Diffluent flow aloft will combine with these low level
winds to create additional rains. Did not make any changes to the
pops, but did bring the near term grids closer to current values.
These changes are transparent in the zones, so not sending out a
zone update at this point. Still looking for areal averages for rain
between an inch and an inch and a half by Monday evening.
&&
.Short Term (Now - Monday Night)...
Issued at 300 PM EDT Sun Mar 10 2013
The approaching surface low continues to strengthen as the
upper-level trough is amplifying over the central CONUS. The surface
low, currently across the Middle Mississippi River Valley, will move
north-northeast to Lake Michigan by Monday morning. This more
northward movement of the surface low will cause the frontal
boundary to slowly progress eastward.
Under cloudy skies, a few sprinkles were present this morning. This
quickly dissipated and cloud cover began to break up by late
morning. This has allowed temperatures to range from the mid 60s to
low 70s early this afternoon, with a little more warming possible.
Southerly winds have also increased across the region, in response
to the strengthening pressure gradient. Gusts have reached the low
to mid 30 mph range, mainly across our southwest CWA (Bowling Green
region) and believe a few more hours of gusts similar to this will
be possible. Lighter wind gusts will be possible across the east and
northeast forecast area.
By this evening, the frontal boundary will approach from the west.
Widespread rain, moderate at times, will move across the western
forecast area late this evening, the central forecast area during
the early morning hours to about daybreak, and across the eastern
forecast area from about daybreak through midday Monday. Expect
precipitation efficient rainfall, as warm-cloud depths range between
8-9K feet, total PWs range between 1 and 1.2 inches, and sub-cloud
layer relative humidity will be 70+ percent. Still looking for
0.75-1.4 inches of rainfall for overall QPF, with the higher amounts
being across south-central Kentucky. This should not cause may
issues, with just some nuisance ponding/flooding and rises on area
rivers and streams. Some low-top showers could develop on the back
side of the departing main precip shield Monday afternoon and exit
the eastern forecast area during the evening hours. Will continue
PoPs Monday afternoon and trend them back from west to east, ending
PoPs around midnight in the east. Still appears showers could mix
down some stronger, sub-severe winds. So, winds of 40 mph are
possible, especially with already strong gradient winds.
Strong gusty winds will subside a bit tonight and transition to
westerly Monday afternoon and evening, as the front pushes through
the forecast area. Expect non-diurnal temperature trends Sunday
night and Monday as colder air filters southeast across the forecast
area. Temperatures will be quite mild tonight, with readings ranging
from the low to mid 50s. Temperatures will trend cooler from
northwest to southeast through the day Monday, with generally low 40
in the northwest to around 50 in the southeast expected by early
Monday evening. Temperatures will continue to cool Monday night,
with lows in the lower 30s anticipated.
.Long Term (Tuesday Night through Sunday)...
Issued at 340 PM EDT Sun Mar 10 2013
Tuesday Night through Thursday Night...
The medium range models are in fairly decent agreement for the
middle of the week. The multi-model consensus is in agreement that
a fairly stout upper trough will push through the region around
mid-week bringing colder than normal temperatures back into the
region. Within the upper trough, the models continue to struggle
with bringing a mid-level vorticity max through the base of the
trough. Using the consensus mean, it appears that this feature will
most likely pass to our north and just bring some clouds down into
the region Wednesday afternoon and evening. The upper trough will
shift to the east on Thursday as some mid-level ridging builds to
the west of the area. We will remain in a northwesterly flow aloft
and will be watching for another mid-level vort max to swing through
the region Thursday night. The timing of this vort max is very much
in question as the deterministic models continue to have timing
issues. Yesterday`s solutions showed the GFS being more progressive
and faster, but today`s solutions show a faster Euro and slower
GFS. For now, will keep some low chc PoPs in for Thursday night
until some better forecast/model continuity.
As for temperatures, the multi-model consensus has trended a little
cooler over the last 24 hours. Therefore, it appears that going a
little cooler on temperatures is probably a good bet at this point,
but nothing too earth shattering. Lows Tuesday and Wednesday night
will cool into the 20s. Highs Tuesday will probably only warm into
the lower 40s in the north with lower-middle 40s in the south. A
little bit of a warm up is expected Thursday with readings warming
into the upper 40s in the north and lower 50s in the south. Lows
Thursday night look to cool back into the mid 30s.
Friday through Sunday...
The long term portion of the forecast can be summed up as a low
confidence forecast at best given the large amount of spread in
today`s deterministic guidance. Utilizing an average of the
multi-model consensus, the upper ridge over the east looks to
eventually get replaced with a broad trough as we get toward the end
of the forecast period. The Euro and GFS both handle the mid-level
wave differently and with different speeds. The GFS lets the wave
slide east and results in a quasi-stationary boundary remaining over
the region from this weekend and into next. On the other hand, the
Euro has been trending with pushing the system on through with the
boundary setting up to our south with a more significant system
developing just beyond the forecast period. Interestingly enough,
the pattern is almost reminiscent of the system that passed through
the Mid-Atlantic last week...though the Euro solutions are a little
more to the south of last weeks track. For now, plan on leaving
conditions partly to mostly cloudy through the period. Will
maintain some low chance PoPs in the forecast but hold off on making
more significant adjustments until some better forecast convergence
emerges.
Temperatures are equally challenging as well. The overall pattern
does support above normal temperatures with highs on Friday warming
into the upper 50s to the lower 60s. Saturday could be a bit warmer
with readings in the lower to middle 60s. Depending on the eventual
frontal position, we trended temperatures back a bit on Sunday and
have gone with a more consensus blend here which results in
temperatures in the middle to upper 50s. Overnight lows through the
period will likely average in the 40s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 104 AM EDT Sun Mar 11 2013
Surface low is now over the lower Great Lakes with upper level low
over southern Iowa. A cold front extends southward from the surface
low along the middle Mississippi River Valley, and will slowly push
east toward the TAF sites through the overnight. Widespread rain
showers are now filtering across the SDF/BWG terminal and will
continue to do so through the overnight, however conditions should
stay generally VFR, outside of the heaviest showers where a brief
drop to MVFR vis is possible. As we approach dawn, the frontal
boundary will begin to move through, and with the lighter winds will
come lower ceilings. Will stay above the MVFR/IFR threshold for now,
but cannot rule it out at this point. Showery activity will persists
through the early afternoon behind the front, as the upper level
trough axis to the west begins to move through. Will return to VFR
by early to mid afternoon with a gusty west wind between 10 and 20
mph and a few gusts around 25 mph.
LEX will widespread rain onset toward dawn, with a brief drop into
the MVFR category for visibilities through midday. Then by mid
afternoon, front moves through with low MVFR ceilings and light rain
shower activity persisting into the early evening hours. Conditions
should return to VFR by mid evening with a steady west wind.
One other note, decided to let low level wind shear mention go as
soundings across the area do not show much of a low level inversion
and low level winds in the 1000-2000 foot range are marginal at this
point.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......MJP
Long Term........MJ
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
600 AM EDT MON MAR 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL RESIDE ALONG THE MID-ATLANTIC COAST TODAY. A
COLD FRONT WILL APPROACH TONIGHT...AND THEN MOVE ACROSS THE AREA
DURING THE MORNING AND EARLY AFTERNOON ON TUESDAY. AN UPPER TROUGH
IS EXPECTED TO LINGER OVER THE NORTHEAST AND MID-ATLANTIC STATES
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LGT SE RETURN FLOW HAS DEVELOPED IN RESPONSE TO HIPRES SHIFTING
OFF THE ERN SEABOARD. ONSHORE COMPONENT TO THE FLOW HAS ADVECTED
MARINE LAYER INLAND ERY THIS MRNG. 11U-3.9U SAT IMAGERY SHOWS
STRATUS DECK HAS ADVANCED WESTWARD TO ABOUT I-95 AT 07Z. FCST
REGARDING INLAND PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN
BETWEEN THE HRRR AND NAM...WHICH HAVE BOTH CAPTURED THIS STRATUS
EVENT WELL THUS FAR. THE HRRR DEVELOPS STRATUS AS FAR WEST AS IAD TO
FDK TO EZF WHILE THE 00Z NAM TAKES IT AS FAR INLAND AS MRB BY
SUNRISE.
LOPRES WILL TRACK NEWD ACROSS THE UPPER MIDWEST TDA WHILE ATTENDANT
COLD FRONT MOVES THRU THE OH VLY. DEEP SLY FLOW WITHIN PRE-FRONTAL
WARM SECTOR BECOMES FURTHER ESTABLISHED TDA. TEMPS FCST IS COMPLEX
TDA AMID VARIABLE CLOUD COVER TDA. GIVEN THE MID MARCH SUN
ANGLE...THERE IS A POTENTIAL FOR STRATUS TO TAKE LONGER TO MIX OUT
THAN MODELS FCST ESPECIALLY TOWARD THE CHSPK BAY. HAVE CUT DOWN MAX
TEMPS SEVERAL DEGREES FROM BIAS-CORRECTED MET. ELSEWHERE...HI CLOUDS
THIS MRNG WILL THICKEN/LOWER THRUOUT THE DAY AS LLVL ISENTROPIC LIFT
DEVELOPS AHEAD OF THE COLD FRONT. HIRES MODEL GUIDANCE IN AGREEMENT
WITH FRONTAL BAND OF PRECIP REMAINING WEST OF THE CWA TDA...BUT A
FEW LGT SHOWERS MAY DEVELOPS OVER THE POTOMAC HIGHLANDS LATE THIS
AFTN.
00Z NAM/GFS IN GOOD AGREEMENT WITH THE COLD FRONT CROSSING THE
CENTRAL APPALACHIANS CLOSE TO MIDNIGHT. STEADIER SHOWERS SHOULD MOVE
INTO THE MTS THIS EVE WHILE LIGHTER AND MORE SCATTERED ACTIVITY
DEVELOPS EAST OF THE BLUE RIDGE. COLD FRONT IS EXPECTED TO CROSS THE
BLUE RIDGE OVNGT WHILE WIDESPREAD SHOWERS SPREAD EWD. WENT WARM WITH
MIN TEMPS TNGT AS SLY FLOW AHEAD OF THE FRONT PREVENTS TEMPS FROM
DROPPING MUCH DURING THE NGT.
&&
.SHORT TERM /TUESDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA TUESDAY...DURING THE MORNING
WEST OF THE BLUE RIDGE AND THEN MIDDAY/EARLY AFTERNOON TOWARD THE
INTERSTATE 95 CORRIDOR. PREFER A NAM/SREF TIMING FOR FROPA/PRECIP
ALTHOUGH GFS/ECMWF AREN/T MUCH DIFFERENT. THIS SHOULD ALLOW SHOWERS
TO TAPER OFF ACROSS THE INTERSTATE 95 CORRIDOR BY EARLY AFTERNOON.
TOTAL RAINFALL LOOKS TO BE ON THE ORDER OF 1/2 TO 3/4 OF AN INCH
ACROSS THE CWA.
IF SHOWERS END AS FORECAST AND PARTIAL CLEARING OCCURS LATER IN THE
AFTERNOON...THEN MAXIMA SHOULD BE ABLE TO RECOVER AOA 60 DEG F
ACROSS MUCH OF THE CWA /SAVE FOR HIGHER ELEVATIONS/. WITH THIS
EXPECTATION AND CONSIDERING RECENT COLD BIASES FROM
GUIDANCE...FAVORED THE WARMER BIAS CORRECTED MAV FOR MAXIMA ON
TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
UPPER TROUGH/SHORTWAVE AND ASSOCIATED REINFORCING FRONT AT THE
SURFACE MOVE THROUGH ON WEDNESDAY. THIS MAY PROMOTE LIGHT
PRECIPITATION ACROSS THE NORTHWEST PORTION OF THE CWA...AND ALSO IS
LIKELY TO BRING MOSTLY CLOUDY AND BLUSTERY CONDITIONS ACROSS THE
CWA.
COOLER AIR WILL MOVE IN BEHIND TUESDAY/S FROPA FOR WEDNESDAY...BUT
COLDEST PERIOD OF THE STRETCH LOOKS TO BE THURSDAY/THURSDAY NIGHT IN
THE WAKE OF THE REINFORCING BOUNDARY.
MID-ATLANTIC REMAINS IN A WEST/NORTHWEST FLOW ALOFT INTO THE
WEEKEND. BOTH GFS AND ECMWF INDICATE A WAVE BRINGING A CHANCE OF
PRECIP SOMETIME IN THE SATURDAY THROUGH SUNDAY TIME FRAME. IT/S A
LOW CONFIDENCE FORECAST ATTM AND CONTINUE LOW POPS FOR MAINLY SHRA
DURING THE DAY AND SHSN AT NIGHT.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STRATUS DECK CONTINUES TO ADVECT INLAND ERY THIS MRNG...RESULTING IN
IFR CIGS. LATEST OBS AND 11U-3.9U SAT IMAGERY SHOWS STRATUS DECK HAS
ADVANCED WESTWARD TO ABOUT DCA AS OF 0730Z. FCST REGARDING INLAND
PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN BETWEEN THE HRRR
AND NAM /BOTH CAPTURED THIS STRATUS EVENT WELL THUS FAR/ WHICH
REACHES IAD BEFORE SUNRISE BUT STAYS EAST OF MRB AND CHO. THE HRRR
DEVELOPS STRATUS AS FAR WEST AS IAD TO FDK TO EZF WHILE THE 00Z NAM
TAKES IT AS FAR INLAND AS MRB BY SUNRISE.
06Z TAFS REFLECTS EROSION OF STRATUS DECK FROM WEST TO EAST DURING
THE MRNG. GIVEN THE MARCH SUN ANGLE...STRATUS MAY BE MORE STUBBORN
TO ERODE THAN MODELS INDICATE. BWI AND MTN ARE MOST PRONE TO STRATUS
HANGING UNTIL MIDDAY...AND POSSIBLY EVEN LATER.
SHOWERS WILL OVERSPREAD THE TERMINALS FROM WEST TO EAST TNGT.
SHOWERS AND CIG/VSBY RESTRICTIONS MAY DEVELOP BEFORE MIDNIGHT AT
MRB/CHO AND OVNGT FARTHER EAST. LLWS ADDED TO TAFS FOR OVNGT AS 50
KT LOW-LEVEL JET CROSSES TERMINALS.
GUIDANCE SUGGESTS IFR CONDITIONS ONGOING AT THE START OF TUESDAY.
FLIGHT RESTRICTIONS WILL ASSOCIATED WITH SHOWERS MOVING THROUGH
DURING THE MORNING PUSH. FROPA THAT BRINGS THE SHOWERS LOOKS TO
OCCUR DURING MIDDAY/EARLY AFTERNOON HOURS AT THE HUBS...WITH A WIND
SHIFT TO THE NORTHWEST. THIS SHOULD ALSO PROMOTE IMPROVING
CONDITIONS TO VFR FOR THE AFTERNOON. REINFORCING COLD FRONT MOVES
THROUGH ON WEDNESDAY WITH THE POTENTIAL FOR GUSTY WINDS.
&&
.MARINE...
SELY WINDS INCREASE THIS MRNG WHILE HIPRES MOVES OFFSHORE. WINDS
BECOME MORE SLY THIS AFTN AND TNGT AS A COLD FRONT APPROACHES FROM
THE WEST. SCA STARTS LATE THIS AFTN FOR THE MAIN STEM OF THE MD
CHSPK BAY AND LOWER TIDAL POTOMAC RVR...WHICH ARE MOST PRONE TO SLY
CHANNELING. SCA IN EFFECT FOR ALL WATERS TNGT.
SCA HAS BEEN EXTENDED OVER THE MD CHESAPEAKE BAY AND LOWER TIDAL
POTOMAC RIVER TUESDAY MORNING FOR ONGOING GUSTY/CHANNELLING
SOUTHERLY FLOW. COLD FRONT MOVES EAST OF THE BAY DURING THE EARLY
AFTERNOON HOURS...WITH A WIND SHIFT TO THE NORTHWEST. REINFORCING
FRONT MOVES THROUGH WEDNESDAY...WITH SCA CONDITIONS LIKELY TO
RETURN.
&&
.TIDES/COASTAL FLOODING...
WITH PERSISTENT SELY FLOW...ANOMALIES REMAIN AT OR JUST BELOW 2 FT
THIS MRNG. ANOMALIES MAY INCREASE A BIT MORE TDA WITH SELY FLOW
EXPECTED TO INCREASE. IF ANOMALIES DO INCREASE A BIT MORE...THAN
ANNAPOLIS WOULD APPROACH MODERATE FLOOD STAGE. A COASTAL FLOOD
WARNING FOR ANNE ARUNDEL COUNTY IS IN EFFECT THRU THIS EVE
ACCORDINGLY. A COASTAL FLOOD ADVISORY WILL CONTINUE INTO TDA ALONG
THE REMAINDER OF THE WRN SHORE OF THE MD CHSPK BAY AND THE TIDAL
POTOMAC RVR.
WILL LIKE TO MONITOR HOW ANOMALIES RESPOND TDA BEFORE EXTENDING THE
WRNG OR ISSUING A WATCH FOR ANNE ARUNDEL SINCE CONFIDENCE IN
REACHING MODERATE THRESHOLD IS TOO LOW TO ISSUE ATTM. CONFIDENT
ON ADVISORY LEVEL /MINOR/ FLOODING CONTINUING INTO TUESDAY.
COLD FRONT MOVES THROUGH THE BAY BY EARLY AFTERNOON TUESDAY.
NORTHWEST WINDS BEHIND THE FRONT SHOULD HELP TO BRING LOWER WATER
LEVELS THEREAFTER...HOWEVER HOW QUICKLY WATER LEVELS LOWER WILL
DETERMINE WHETHER OR NOT ADVISORIES MAY CONTINUE FOR THE
SUBSEQUENT HIGH TIDE CYCLE LATER TUESDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ007-
011-013-016>018.
COASTAL FLOOD WARNING UNTIL MIDNIGHT EDT TONIGHT FOR MDZ014.
VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
VAZ052>055-057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 PM EDT
TUESDAY FOR ANZ530-531-538>541.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM EDT
TUESDAY FOR ANZ532>534-537-542-543.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EDT
TUESDAY FOR ANZ535.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM EDT
TUESDAY FOR ANZ536.
&&
$$
SYNOPSIS...JRK/BPP
NEAR TERM...JRK
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...JRK/BPP
MARINE...JRK/BPP
TIDES/COASTAL FLOODING...JRK/BPP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
422 AM EDT MON MAR 11 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE MIDWEST TODAY. EXPECT
RAIN TO OVERSPREAD THE REGION LATE TODAY AND TONIGHT. BELOW
NORMAL TEMPERATURES WILL RETURN BY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF SPRINKLES...ASSOCIATED WITH SHORTWAVE OVER CENTRAL
OHIO...IS MOVING NORTHWARD TOWARD LAKE ERIE. LATEST MODEL DATA
KEEPS THIS SHORTWAVE TO THE NORTH AND WEST FOLLOWING THE STRONG
SOUTHERLY FLOW ALOFT.
BROAD AREA OF HIGH CLOUDS WILL COVER THE AREA THROUGH THE MORNING
HOURS. CLOUDS WILL LOWER THIS AFTERNOON FROM THE WEST...AS SLOW
MOVING FRONT APPROACHES. ABOVE AVE CONFIDENCE ON SLOWER FORECAST
TODAY. LATEST HIRES MODELS ARE IN GOOD AGREEMENT WITH OP MODELS
THAT MAIN AREA OF RAIN WILL SLOWLY MOVE THROUGH THE WEST LATE THIS
MORNING AND THROUGH THE AFTERNOON AND WILL NOT REACH THE EASTERN
HALF UNTIL THIS EVE. AN ISO SHOWER OR SPRINKLES IS POSSIBLE AHEAD
OF THE MAIN AREA.
WITH AREA IN THE WARM SECTOR...TEMPS WILL RISE ABOVE NORMAL AGAIN
TODAY. LAMP MODEL HAS DONE PRETTY WELL WITH WARM AIR MASS...SO
WILL LEAN ON THAT FOR HIGHS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
EXPTG SHRA WITH FROPA OVRNGT. COLD AIR ADVCTN WL BEGIN AFT FROPA
WITH LOW CHCS FOR PCPN. CRITICAL THICKNESSES/PROFILES INDICATE
SHRA MAY MIX WITH SHSN TUE. HIGH TEMPS ARE EXPD TO DROP BLO
SEASONAL AVGS AGAIN TUE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD NW FLOW AND AN UPR LVL TROF WL BRING INCRG SHSN CHCS TO THE
RGN THRU WED. SFC HI PRES GRDLY BLDS IN THU AND THU NGT. A WK SFC
LOW IS EXPD TO QUICKLY TRACK SEWD ACRS THE OH VLY RGN FRI...WITH A
CHC FOR SHRA/SHSN MAINLY S OF PIT. A QUASI STNRY FNT IS EXPD TO
SET UP ACRS THE OH/TN VLY RGNS OVR THE WK END...CONTG THE CHC FOR
SHRA/SHSN MAINLY S OF PIT. TEMPS EXPD TO REMAIN BLO SEASONAL AVGS
THRU THE PD.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR WEA WL CONT THRU MONDAY...HOWEVER...LLWS WL BE A CONCERN LATE
TNGT AND EARLY MONDAY AS DEEPENING LOW PRES DVLPS TWD THE WRN GREAT
LAKES. LATEST NAM AND RAP MDL SNDINGS INDICATE SUFFICIENT
ENHANCEMENTMENT OF THE LLVL JET TO ADD A WIND SHEAR MENTION FOR THE
OVRNGT HRS IN ALL...BUT ERNMOST TAF SITES.
THIS STRONG WARM ADVCTN REGIME SHOULD CAP THE BNDRY LYR...AND THUS
LIMIT GUSTS ON MONDAY. 20 TO 25 KT SFC GUSTS WL SUFFICE FOR THE
CURRENT PROGNOSIS.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
THE CDFNT EXTENDING FM THE AFOREMENTIONED GREAT LAKES LOW IS
FORECAST FOR A MONDAY NGT CROSSING OF THE UPR OH VALLEY.
RESTRICTIONS IN SHRA SHOULD BE ANTICIPATED WITH THAT PASSAGE...AND
IN THE COLD ADVCTN REGIME BEHIND A REINFORCING FRONT PROJECTED FOR
TUESDAY.
HIGH PRES IS EXPECTED TO RTN GENL VFR TO REGIONAL PORTS FOR LTR
THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EDT MON MAR 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL RESIDE ALONG THE MID-ATLANTIC COAST TODAY. A
COLD FRONT WILL APPROACH TONIGHT...AND THEN MOVE ACROSS THE AREA
DURING THE MORNING AND EARLY AFTERNOON ON TUESDAY. AN UPPER TROUGH
IS EXPECTED TO LINGER OVER THE NORTHEASTERN QUARTER OF THE COUNTRY
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LGT SE RETURN FLOW HAS DEVELOPED IN RESPONSE TO HIPRES SHIFTING
OFF THE ERN SEABOARD. ONSHORE COMPONENT TO THE FLOW HAS ADVECTED
MARINE LAYER INLAND ERY THIS MRNG. 11U-3.9U SAT IMAGERY SHOWS
STRATUS DECK HAS ADVANCED WESTWARD TO ABOUT I-95 AT 07Z. FCST
REGARDING INLAND PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN
BETWEEN THE HRRR AND NAM...WHICH HAVE BOTH CAPTURED THIS STRATUS
EVENT WELL THUS FAR. THE HRRR DEVELOPS STRATUS AS FAR WEST AS IAD TO
FDK TO EZF WHILE THE 00Z NAM TAKES IT AS FAR INLAND AS MRB BY
SUNRISE.
LOPRES WILL TRACK NEWD ACROSS THE UPPER MIDWEST TDA WHILE ATTENDANT
COLD FRONT MOVES THRU THE OH VLY. DEEP SLY FLOW WITHIN PRE-FRONTAL
WARM SECTOR BECOMES FURTHER ESTABLISHED TDA. TEMPS FCST IS COMPLEX
TDA AMID VARIABLE CLOUD COVER TDA. GIVEN THE MID MARCH SUN
ANGLE...THERE IS A POTENTIAL FOR STRATUS TO TAKE LONGER TO MIX OUT
THAN MODELS FCST ESPECIALLY TOWARD THE CHSPK BAY. HAVE CUT DOWN MAX
TEMPS SEVERAL DEGREES FROM BIAS-CORRECTED MET. ELSEWHERE...HI CLOUDS
THIS MRNG WILL THICKEN/LOWER THRUOUT THE DAY AS LLVL ISENTROPIC LIFT
DEVELOPS AHEAD OF THE COLD FRONT. HIRES MODEL GUIDANCE IN AGREEMENT
WITH FRONTAL BAND OF PRECIP REMAINING WEST OF THE CWA TDA...BUT A
FEW LGT SHOWERS MAY DEVELOPS OVER THE POTOMAC HIGHLANDS LATE THIS
AFTN.
00Z NAM/GFS IN GOOD AGREEMENT WITH THE COLD FRONT CROSSING THE
CENTRAL APPALACHIANS CLOSE TO MIDNIGHT. STEADIER SHOWERS SHOULD MOVE
INTO THE MTS THIS EVE WHILE LIGHTER AND MORE SCATTERED ACTIVITY
DEVELOPS EAST OF THE BLUE RIDGE. COLD FRONT IS EXPECTED TO CROSS THE
BLUE RIDGE OVNGT WHILE WIDESPREAD SHOWERS SPREAD EWD. WENT WARM WITH
MIN TEMPS TNGT AS SLY FLOW AHEAD OF THE FRONT PREVENTS TEMPS FROM
DROPPING MUCH DURING THE NGT.
&&
.SHORT TERM /TUESDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA TUESDAY...DURING THE MORNING
WEST OF THE BLUE RIDGE AND THEN MIDDAY/EARLY AFTERNOON TOWARD THE
INTERSTATE 95 CORRIDOR. PREFER A NAM/SREF TIMING FOR FROPA/PRECIP
ALTHOUGH GFS/ECMWF AREN/T MUCH DIFFERENT. THIS SHOULD ALLOW SHOWERS
TO TAPER OFF ACROSS THE INTERSTATE 95 CORRIDOR BY EARLY AFTERNOON.
TOTAL RAINFALL LOOKS TO BE ON THE ORDER OF 1/2 TO 3/4 OF AN INCH
ACROSS THE CWA.
IF SHOWERS END AS FORECAST AND PARTIAL CLEARING OCCURS LATER IN THE
AFTERNOON...THEN MAXIMA SHOULD BE ABLE TO RECOVER AOA 60 DEG F
ACROSS MUCH OF THE CWA /SAVE FOR HIGHER ELEVATIONS/. WITH THIS
EXPECTATION AND CONSIDERING RECENT COLD BIASES FROM
GUIDANCE...FAVORED THE WARMER BIAS CORRECTED MAV FOR MAXIMA ON
TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
UPPER TROUGH/SHORTWAVE AND ASSOCIATED REINFORCING FRONT AT THE
SURFACE MOVE THROUGH ON WEDNESDAY. THIS MAY PROMOTE LIGHT
PRECIPITATION ACROSS THE NORTHWEST PORTION OF THE CWA...AND ALSO IS
LIKELY TO BRING MOSTLY CLOUDY AND BLUSTERY CONDITIONS ACROSS THE
CWA.
COOLER AIR WILL MOVE IN BEHIND TUESDAY/S FROPA FOR WEDNESDAY...BUT
COLDEST PERIOD OF THE STRETCH LOOKS TO BE THURSDAY/THURSDAY NIGHT IN
THE WAKE OF THE REINFORCING BOUNDARY.
MID-ATLANTIC REMAINS IN A WEST/NORTHWEST FLOW ALOFT INTO THE
WEEKEND. BOTH GFS AND ECMWF INDICATE A WAVE BRINGING A CHANCE OF
PRECIP SOMETIME IN THE SATURDAY THROUGH SUNDAY TIME FRAME. IT/S A
LOW CONFIDENCE FORECAST ATTM AND CONTINUE LOW POPS FOR MAINLY SHRA
DURING THE DAY AND SHSN AT NIGHT.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
STRATUS DECK CONTINUES TO ADVECT INLAND ERY THIS MRNG...RESULTING IN
IFR CIGS. LATEST OBS AND 11U-3.9U SAT IMAGERY SHOWS STRATUS DECK HAS
ADVANCED WESTWARD TO ABOUT DCA AS OF 0730Z. FCST REGARDING INLAND
PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN BETWEEN THE HRRR
AND NAM /BOTH CAPTURED THIS STRATUS EVENT WELL THUS FAR/ WHICH
REACHES IAD BEFORE SUNRISE BUT STAYS EAST OF MRB AND CHO. THE HRRR
DEVELOPS STRATUS AS FAR WEST AS IAD TO FDK TO EZF WHILE THE 00Z NAM
TAKES IT AS FAR INLAND AS MRB BY SUNRISE.
06Z TAFS REFLECTS EROSION OF STRATUS DECK FROM WEST TO EAST DURING
THE MRNG. GIVEN THE MARCH SUN ANGLE...STRATUS MAY BE MORE STUBBORN
TO ERODE THAN MODELS INDICATE. BWI AND MTN ARE MOST PRONE TO STRATUS
HANGING UNTIL MIDDAY...AND POSSIBLY EVEN LATER.
SHOWERS WILL OVERSPREAD THE TERMINALS FROM WEST TO EAST TNGT.
SHOWERS AND CIG/VSBY RESTRICTIONS MAY DEVELOP BEFORE MIDNIGHT AT
MRB/CHO AND OVNGT FARTHER EAST. LLWS ADDED TO TAFS FOR OVNGT AS 50
KT LOW-LEVEL JET CROSSES TERMINALS.
GUIDANCE SUGGESTS IFR CONDITIONS ONGOING AT THE START OF TUESDAY.
FLIGHT RESTRICTIONS WILL ASSOCIATED WITH SHOWERS MOVING THROUGH
DURING THE MORNING PUSH. FROPA THAT BRINGS THE SHOWERS LOOKS TO
OCCUR DURING MIDDAY/EARLY AFTERNOON HOURS AT THE HUBS...WITH A WIND
SHIFT TO THE NORTHWEST. THIS SHOULD ALSO PROMOTE IMPROVING
CONDITIONS TO VFR FOR THE AFTERNOON. REINFORCING COLD FRONT MOVES
THROUGH ON WEDNESDAY WITH THE POTENTIAL FOR GUSTY WINDS.
&&
.MARINE...
SELY WINDS INCREASE THIS MRNG WHILE HIPRES MOVES OFFSHORE. WINDS
BECOME MORE SLY THIS AFTN AND TNGT AS A COLD FRONT APPROACHES FROM
THE WEST. SCA STARTS LATE THIS AFTN FOR THE MAIN STEM OF THE MD
CHSPK BAY AND LOWER TIDAL POTOMAC RVR...WHICH ARE MOST PRONE TO SLY
CHANNELING. SCA IN EFFECT FOR ALL WATERS TNGT.
SCA HAS BEEN EXTENDED OVER THE MD CHESAPEAKE BAY AND LOWER TIDAL
POTOMAC RIVER TUESDAY MORNING FOR ONGOING GUSTY/CHANNELLING
SOUTHERLY FLOW. COLD FRONT MOVES EAST OF THE BAY DURING THE EARLY
AFTERNOON HOURS...WITH A WIND SHIFT TO THE NORTHWEST. REINFORCING
FRONT MOVES THROUGH WEDNESDAY...WITH SCA CONDITIONS LIKELY TO
RETURN.
&&
.TIDES/COASTAL FLOODING...
WITH PERSISTENT SELY FLOW...ANOMALIES REMAIN AT OR JUST BELOW 2 FT
THIS MRNG. ANOMALIES MAY INCREASE A BIT MORE TDA WITH SELY FLOW
EXPECTED TO INCREASE. IF ANOMALIES DO INCREASE A BIT MORE...THAN
ANNAPOLIS WOULD APPROACH MODERATE FLOOD STAGE. A COASTAL FLOOD
WARNING FOR ANNE ARUNDEL COUNTY IS IN EFFECT THRU THIS EVE
ACCORDINGLY. A COASTAL FLOOD ADVISORY WILL CONTINUE INTO TDA ALONG
THE REMAINDER OF THE WRN SHORE OF THE MD CHSPK BAY AND THE TIDAL
POTOMAC RVR.
WILL LIKE TO MONITOR HOW ANOMALIES RESPOND TDA BEFORE EXTENDING THE
WRNG OR ISSUING A WATCH FOR ANNE ARUNDEL SINCE CONFIDENCE IN
REACHING MODERATE THRESHOLD IS TOO LOW TO ISSUE ATTM.
CONFIDENT ON ADVISORY LEVEL /MINOR/ FLOODING CONTINUING INTO TUESDAY.
NW FLOW BHD FNT SHUD ALLEVIATE CSTL FLOOD CONCERNS...BUT WE WL
SEE HOW QUICKLY THAT WL FOLLOW.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ007-
011-013-016>018.
COASTAL FLOOD WARNING UNTIL MIDNIGHT EDT TONIGHT FOR MDZ014.
VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
VAZ052>055-057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 PM EDT
TUESDAY FOR ANZ530-531-538>541.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM EDT
TUESDAY FOR ANZ532>534-537-542-543.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EDT
TUESDAY FOR ANZ535.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM EDT
TUESDAY FOR ANZ536.
&&
$$
SYNOPSIS...JRK/BPP
NEAR TERM...JRK
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...JRK/BPP
MARINE...JRK/BPP
TIDES/COASTAL FLOODING...JRK/BPP/HTS
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
138 AM EDT MON MAR 11 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE MIDWEST TODAY. EXPECT
RAIN TO OVERSPREAD THE REGION LATE TODAY AND TONIGHT. BELOW
AVERAGE TEMPERATURES WILL RETURN BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
LITTLE CHANGE TO OVERNIGHT. MADE MINOR ADJUSTMENTS TO TEMPS AND
CLOUD COVER.
MODELS ARE IN GOOD AGREEMENT SLOWLY THE ONSET OF RAIN TODAY. WILL
HOLD OF THE MENTION IN THE WESTERN HALF UNTIL THE AFTERNOON...WITH
RAIN NOT REACHING THE EASTERN HALF UNTIL THIS EVE.
EXPECT ANOTHER DAY OF ABOVE NORMAL TEMPS WITH SOUTHERLY WINDS
STRENGTHENING AHEAD OF THE SFC FRONT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
EXPTG SHRA WITH FROPA OVRNGT. COLD AIR ADVCTN WL BEGIN AFT FROPA
WITH LOW CHCS FOR PCPN. CRITICAL THICKNESSES/PROFILES INDICATE
SHRA MAY MIX WITH SHSN TUE. HIGH TEMPS ARE EXPD TO DROP BLO
SEASONAL AVGS AGAIN TUE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD NW FLOW AND AN UPR LVL TROF WL BRING INCRG SHSN CHCS TO THE
RGN THRU WED. SFC HI PRES GRDLY BLDS IN THU AND THU NGT. A WK SFC
LOW IS EXPD TO QUICKLY TRACK SEWD ACRS THE OH VLY RGN FRI...WITH A
CHC FOR SHRA/SHSN MAINLY S OF PIT. A QUASI STNRY FNT IS EXPD TO
SET UP ACRS THE OH/TN VLY RGNS OVR THE WK END...CONTG THE CHC FOR
SHRA/SHSN MAINLY S OF PIT. TEMPS EXPD TO REMAIN BLO SEASONAL AVGS
THRU THE PD.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR WEA WL CONT THRU MONDAY...HOWEVER...LLWS WL BE A CONCERN LATE
TNGT AND EARLY MONDAY AS DEEPENING LOW PRES DVLPS TWD THE WRN GREAT
LAKES. LATEST NAM AND RAP MDL SNDINGS INDICATE SUFFICIENT
ENHANCEMENTMENT OF THE LLVL JET TO ADD A WIND SHEAR MENTION FOR THE
OVRNGT HRS IN ALL...BUT ERNMOST TAF SITES.
THIS STRONG WARM ADVCTN REGIME SHOULD CAP THE BNDRY LYR...AND THUS
LIMIT GUSTS ON MONDAY. 20 TO 25 KT SFC GUSTS WL SUFFICE FOR THE
CURRENT PROGNOSIS.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
THE CDFNT EXTENDING FM THE AFOREMENTIONED GREAT LAKES LOW IS
FORECAST FOR A MONDAY NGT CROSSING OF THE UPR OH VALLEY.
RESTRICTIONS IN SHRA SHOULD BE ANTICIPATED WITH THAT PASSAGE...AND
IN THE COLD ADVCTN REGIME BEHIND A REINFORCING FRONT PROJECTED FOR
TUESDAY.
HIGH PRES IS EXPECTED TO RTN GENL VFR TO REGIONAL PORTS FOR LTR
THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 PM EDT TUE MAR 12 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER THE GREAT LKS BTWN UPR RDGS ALONG THE W COAST AND OFF
THE E COAST. WITH DEEP CYC NW FLOW...ABUNDANT MSTR SHOWN ON THE 12Z
GRB RAOB...AND H85 TEMPS IN THE -13C TO -16C RANGE...SHSN HAVE BEEN
COMMON OVER THE CWA TODAY UNDER CLDY SKIES...ESPECIALLY NEAR LK SUP
IN AREAS FAVORED BY THE NW LLVL FLOW. THE SN HAS BEEN RATHER FLUFFY
AS MODEL SDNGS INDICATE THE DGZ IS SEVERAL THOUSAND FEET DEEP GIVEN
FVRBL H85 TEMPS. THERE IS A SHRTWV DROPPING SEWD THRU MN ACCOMPANIED
BY A FAIRLY WELL DEFINED TROF AT H85-7. UPSTREAM OBS AT GRAND MARAIS
ON THE MN NORTH SHORE AND AT THUNDER BAY IN ONTARIO INDICATE SOME
HEAVIER SHSN ACCOMPANY THIS TROF PASSAGE FARTHER TO THE E-SE AWAY FM
DRIER AIR SHOWN ON THE 12Z INL/YPL RAOBS. APRCHG FCST ISSUANCE...
SOME OF THE HEAVIER SHSN HAVE ARRIVED OVER THE WRN COUNTIES. CMX HAS
REPORTED VSBY DOWN TO 1/4SM AT TIMES...AND REPORTS FM GOGEBIC COUNTY
INDICATE AS MUCH AS 5 INCHES OF SN FELL THERE THRU 18Z.
LATE THIS AFTN/TNGT...AS SHRTWV IN MN DIGS SEWD...GUIDANCE SHOWS
PRONOUNCED H85 WSHFT ASSOCIATED WITH TROF PASSAGE AS WELL AS AREA OF
H85-5 QVECTOR CNVGC CROSSING THE CWA NW-SE. EXPECT SHSN TO INCRS IN
INTENSITY WITH THIS ENHANCED SUPPORT IN PRESENCE OF DEEP MSTR. FCST
SDNGS CONTINUE TO SHOW UVV FOCUSED IN THE DGZ...SO EXPECT HI SN/
WATER RATIOS AOA 20:1. LATER TNGT IN THE WAKE OF THE TROF PASSAGE...
DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE OF THE SHRTWV/TROF WL
CONSPIRE TO LOWER INVRN BASES DOWN TO 2-3K FT AGL. WITH ARRIVAL OF
LLVL DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS...EXPECT LES TO DIMINISH
FAIRLY STEADILY AFT 06Z. OVERALL...SHIFTING WINDS FM NW TO N AND
LIMITED 6-9HR WINDOW OR SO FOR HEAVIER SHSN WL LIMIT TOTAL SN
FALL...SO EXPECT SN TOTALS TO REMAIN WITHIN ADVY LIMITS DESPITE
FVRBL SN/WATER RATIOS. THGE ONLY EXCEPTION IS OVER THE FAR W...WHERE
SOME HEAVY SN FELL DURING THE AFTN AS NOTED ABV. SINCE THERE WL BE
PERIODS OF +SHSN THRU THIS EVNG IN THAT AREA WITH SOME FOCUSED LLVL
CNVGC IN FVRBL CYC NNW FLOW...OPTED TO UPGRADE ADVY TO A WARNING FOR
GOGEBIC/ONTONAGON COUNTIES. ALSO EXTENDED ADVY OVER THE ERN ZNS THRU
12Z GIVEN MORE PERSISTENT FORCING/DEEPER MSTR THERE.
WED...AXIS OF MUCH DRIER AIR WITH H85 DEWPTS AS LO AS -40C AS WELL
AS DEEP LYR QVECTOR DVGC/SUBSIDENCE UNDER STEADILY RISING H5 HGTS
FOLLOWING SHIFT OF UPR TROF AXIS TO THE E WL RESULT IN MAINLY DRY WX
AFTER LINGERING SHSN OVER MAINLY THE E DIMINISH IN THE MRNG. IN
FACT...FCST SDNGS SUG SKIES MAY TURN MOSUNNY IN THE AFTN...
ESPECIALLY NEAR LK SUP WITH A TENDENCY FOR CLRG OVER THE WATER UNDER
STRENGTHENING LATE WINTER SUNSHINE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
TO START THE LONG TERM PERIOD...OVERVIEW OF LARGE SCALE FEATURES
TROUGH OVER GREAT LAKES AND EASTERN CANADA WITH BROAD RIDGING
EXTENDING WELL UPSTREAM INTO EASTERN PORTION OF PACIFIC OCEAN.
FARTHER UPSTREAM TROUGHING IS PRESENT NORTH OF HAWAII. THAT TROUGH
IS ESSENTIALLY EXTENSION OF TROUGHING RESIDING OVER NORTHERN
PORTIONS OF CANADA ON NORTHERN PORTION OF WESTERN CONUS RIDGE. OVER
TIME...TROUGH OVER GREAT LAKES SYNCS UP WITH TROUGHING OVER NORTHERN
CANADA RESULTING IN FAST AND ACTIVE WEST-NORTHWEST FLOW ACROSS
MOST OF THE CONUS THROUGH THE UPCOMING WEEKEND.
TWO SHORTWAVES PROGGED TO DROP THROUGH IN THIS FLOW PATTERN INTO
THIS WEEKEND. FIRST WAVE ALONG WITH WEAK SFC-H85 LOW-LEVEL WARM AIR
ADVECTION GLANCES UPR LAKES TO WEST ON THURSDAY. WAVE IS DIGGING
INTO THE MEAN TROUGH WHICH FAVORS MORE OF A SOUTH AND/OR WEST TRACK
AND IS PRETTY PROGRESSIVE. ALSO LOOKS LIKE ANY UPPER JET SUPPORT
REMAINS WEST OF UPR MICHIGAN. MODELS VARY WILDLY FROM SOUTH TO NORTH
WHERE THE MOST QPF/SNOW IS EXPECTED. GEM-NH ON SOUTHERN EXTREME...
TRACKING ACROSS IOWA...WHILE NAM IS OVER WESTERN UPR MICHIGAN. NAM
IS ON NORTH EDGE OF EVEN SREF...SO IT IS CERTAINLY AN OUTLIER. GFS
AND ECMWF IN BTWN...BUT ARE STILL MAINLY OVER WISCONSIN. SINCE THERE
IS A SLIGHT EASTWARD TREND IN MODELS...WILL BRING CHANCE POPS OVER
WESTERN CWA ON THURSDAY. OTHER ISSUE...PREVIOUSLY MENTIONED BY MID
SHIFT...IS POSSIBLE FREEZING DRIZZLE LATER THURSDAY INTO THURSDAY
NIGHT. BASED ON FORECAST SOUNDINGS...WI BORDER/SCNTRL...WILL HAVE
BEST CHANCE SEEING THIS ONCE ANY SNOW DECREASES. ELSEWHERE...THINK
TOO MUCH DRIER AIR IS AROUND BLO H85 TO HAVE IN THERE. SINCE AM NOT
CERTAIN WHERE ULTIMATELY THE STEADIER SNOW SETS UP OVR CWA...IF IT
DOES AT ALL...WILL KEEP FZDZ OUT OF FCST.
COUPLE OF SUBTLE THINGS HAPPEN LATER THURSDAY INTO THURSDAY NIGHT
THAT MAY HAVE LARGE IMPACT ON FORECAST FOR FRIDAY. ALL MODELS INDICATE
STRONGER NORTHERN STREAM WAVE TRACKS WELL TO THE NORTH OVER NORTHWEST
ONTARIO THURSDAY NIGHT. WE ARE GOOD THERE. TROUBLE IS THAT SAME
MODELS DIFFER ON HOW FAR SOUTH TO BRING LOW-LEVEL COLD AIR IN WAKE OF
SHORTWAVE BY FRIDAY MORNING. GEM-NH FARTHER SOUTH WITH COLD AIR AND
TRENDS FROM GFS ALSO INDICATE FARTHER SOUTH LOW-LEVEL TEMPERATURE
GRADIENT AT SFC-H85. ECMWF NOT AS COLD THOUGH. LOCATION OF TIGHTER
LOW-LEVEL TEMPERATURE GRADIENT COULD PAVE THE WAY FOR WHERE HEAVIER
QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE AND SFC-H85 LOWS MOVE IN FROM
NORTHERN PLAINS.
THIS SECOND SHORTWAVE IS MUCH STRONGER THAN ONE MOVING THROUGH 24 HR
EARLIER AND HAS POTENTIAL TO BRING WIDESRPEAD SNOW TO UPPER LAKES ON
FRIDAY. WHERE EVER LOW-LEVEL BAROCLINIC ZONE SETS UP THERE ARE
ENHANCING FACTORS THAT MAY RESULT IN SWATH OF MODERATE TO HEAVY SNOW
INCLUDING DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK
DROPPING INTO GREAT LAKES FROM ONTARIO...DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS OVR 3G/KG...AND OVERALL STRENGTHENING SFC-H85
LOWS/LOW-LEVEL FLOW. ADVY LEVEL SNOWS CERTAINLY POSSIBLE. INCREASED
POPS TO LIKELY OVER WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER
THAT SNOW OCCURS. WWD DAY 3 GRAPHICS INDICATE UP TO 4 INCHES OVER
WEST THIRD OF CWA ON FRIDAY. IF FARTHER NORTH ECMWF AND GEM-NH ARE
CORRECT...THEN LIKELY POPS WILL BE NEEDED FOR MOST AREAS ON FRIDAY.
AT FIRST GLANCE A MAINLY QUIET WEEKEND AS HIGH PRESSURE IS MAIN
FEATURE OVER REGION. COULD BE RE-INFORCING SHOT OF COLDER AIR AND
SOME DEEPER MOISTURE COME IN LATER SATURDAY AND SATURDAY NIGHT.
GFS/ECMWF INDICATE INCREASE IN POPS DURING THAT TIME. KEPT CHANCY
POPS IN ALONG LK SUPERIOR WITH ADDED POTENTIAL FOR LK EFFECT AS H85
TEMPS DROP INTO THE -15C TO -20C RANGE. RECORD SETTING WARMTH OF MID
MARCH IN 2012 WILL BE BUT A DISTANT MEMORY COMPARED TO THE CHILL OF
THIS YEAR.
COOL AND ACTIVE PATTERN CONTINUES INTO EARLY NEXT WEEK...AND
PROBABLY EVEN INTO LATER MARCH AS WELL. CERTAINLY NOT DONE WITH
WINTER YET. DEEPER SHORTWAVE TROUGH EMERGES FROM TROUGHING OVER
NORTHERN CANADA AND EVENTUALLY TRACKS ACROSS ROCKIES LATE IN THE
WEEKEND. THIS TROUGH THEN DEEPENS ACROSS THE MIDDLE CONUS MONDAY AND
MOVES INTO THE GREAT LAKES ON TUESDAY. DEEPENING LOW PRESSURE SYSTEM
RESULTS WHICH DRAWS UP GULF MOISTURE AND COULD LEAD TO SIGNIFICANT
SNOW SOMEWHERE UPPER MIDWEST THROUGH THE GREAT LAKES...INCLUDING UPR
MICHIGAN. OVERALL THE ECMWF IS DEEPER AND FARTHER NORTH WITH SFC
LOW...THOUGH LATEST RUN BACKED OFF WITH STRENGTH OF LOW. GFS IS MORE
SUPPRESSED WITH TRACK OF SFC LOW. WPC...FORMALLY HPC...HAND DRAWN
PROGS BTWN THE TWO WITH LOW MOVING ACROSS LOWER LAKES AND UPR
MICHIGAN JUST ON THE FRINGE. CONSENSUS POPS ARE IN THE CHANCE RANGE
WHICH IS FINE AT THIS POINT. GIVEN NORTHEAST WINDS AND COOLER
AIR...INCREASED POPS CLOSER TO LK SUPERIOR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 740 PM EDT TUE MAR 12 2013
PREVAILING LIFR CONDITIONS SHOULD LINGER THRU MUCH OF THE EVENING AT
KCMX AND ESPECIALLY KIWD AS LAKE ENHANCED SNOW CONTINUES WITH
DISTURBANCE/TROF PASSING ACROSS THE AREA. SIMILAR TO WHAT HAS
HAPPENED OVER THE LAST FEW HRS...EXPECT FLUCTUATIONS TO IFR AT
TIMES. AT KSAW...IFR CONDITIONS WILL CONTINUE THIS EVENING...THOUGH
THERE MAY BE FLUCTUATIONS DOWN TO LIFR LATE EVENING AS WIND SHIFT TO
A MORE NRLY DIRECTION IMPROVES UPSLOPE/LAKE ENHANCED SNOWFALL.
SUBSIDENCE/STRONG DRYING IN THE WAKE OF THE TROF PASSAGE WILL RESULT
IN CONDITIONS IMPROVING TO MVFR AT ALL 3 SITES OVERNIGHT. MAY SEE
MVFR CIGS SCATTER OUT WED AFTN UNDER CONTINUED DRYING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE MAR 12 2013
UNDER THE TIGHTENING PRES GRADIENT IN THE WAKE OF A TROF PASSAGE
THIS EVENING...EXPECT A N GALE UP TO 35 KTS OVER PORTIONS OF
NCENTRAL LAKE SUP MUCH OF TONIGHT. FREEZING SPRAY WILL BE
WIDESPREAD. AS THE GRADIENT WEAKENS LATE TONIGHT THRU WED...THE
WINDS WILL GRADUALLY DIMINISH AND BACK TOWARD THE NW WITH APPROACH
OF HI PRES FROM THE W. WINDS OF LESS THAN 20 KTS PERSIST INTO
THURSDAY AS HIGH PRESSURE SLIDES ACROSS. SOUTHWESTERLY RETURN FLOW
ON BACK SIDE OF HIGH MAY GET GUSTY OVER 25 KTS BY THU NIGHT. COLD
FRONT SHIFTS THROUGH OVERNIGHT THURSDAY NIGHT WITH NORTHWEST WINDS
TRYING TO REACH 30 KTS. NORTHERLY WINDS TO 25 KTS CONTINUE INTO FRI.
WINDS DIMINISH THROUGH REST OF WEEKEND AS HIGH PRESSURE RETURNS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR MIZ006-007-
085.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR MIZ001-
003>005-084.
LAKE EFFECT SNOW WARNING UNTIL 2 AM EDT /1 AM CDT/ WEDNESDAY FOR
MIZ002-009.
LAKE SUPERIOR...
GALE WARNING UNTIL 5 AM EDT WEDNESDAY FOR LSZ243-244-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 PM EDT MON MAR 11 2013
.UPDATE...
ISSUED AT 636 PM EDT MON MAR 11 2013
PER WATER VAPOR IMAGERY...SHORTWAVE LIFTING N THRU WRN LWR MI IS
LOOKING INCREASINGLY IMPRESSIVE...AND IR IMAGERY SHOWS RAPIDLY
COOLING CLOUD TOPS THRU NRN LWR MI AS DEEP LAYER FORCING
STRENGTHENS. AS A RESULT...RADAR IMAGERY SHOWS EXPANDING PCPN ACROSS
NRN LWR MI. HAVE INCREASED POPS TO CATEGORICAL OVER THE FAR ERN FCST
AREA FOR SEVERAL HRS THIS EVENING AS EXPANDING/INTENSIFYING PCPN
SHIELD LIFTS N. COLUMN SHOULD RAPIDLY COOL...GIVING A QUICK
TRANSITION FROM MOSTLY LIQUID TO SNOW AS PCPN ARRIVES. INCLUDED 1-2
INCH SNOW AMOUNTS ACROSS LUCE COUNTY...BUT WILL NEED TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HRS AS IT`S NOT OUT OF THE QUESTION
THAT THIS COULD TURN INTO AN ADVY TYPE SNOW EVENT OVER THE FAR E
GIVEN THE STRENGTHENING SHORTWAVE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF OVER
CENTRAL AND ERN NAMERICA. NEGATIVELY TILTED CLOSED LO OVER THE LOWER
GRT LKS IS TENDING TO LIFT TO THE NE AS ANOTHER SHRTWV DROPPING THRU
SCENTRAL CANADA DIGS INTO THE NRN PLAINS. THE SFC LO ASSOCIATED WITH
THIS DISTURBANCE HAS PUSHED TO NEAR MANISTIQUE AS OF MID AFTN. SFC
TEMPS AT ISQ/ERY HAVE RISEN INTO THE MID/UPR 30S TO THE E OF THE SFC
LO...AND THERE IS SOME FOG HERE WITH THE DRY AIR MOVING OVER
LINGERING LLVL MSTR. THE ARRIVAL OF THE DRY SLOT ASSOCIATED WITH THE
UPR LO HAS ENDED MOST OF THE PCPN EXCEPT OVER THE WRN COUNTIES...
WHICH LIE UNDER THE DEFORMATION ZN ON THE CYC SIDE OF THE H7 LO
TRACK. PERIODS OF SN HAVE BEEN MOST PERSISTENT IN THESE AREAS
TDAY...WITH SN FALL RATES UP TO 0.5-0.75 INCH/HR. ALTHOUGH THE DRY
SLOT HAS SWEPT THRU THE CNTRL COUNTIES...SOME -SN CONTINUES OVER
MAINLY NCENTRAL MQT COUNTY WITH CYC UPSLOPE N WIND PROVIDING
SUFFICIENT LIFT. ANOTHER AREA OF -SHRASN ASSOCIATED WITH THE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THE UPR LO IS APRCHG THE SE
COUNTIES...BUT PRESENCE OF LARGER SCALE DRY SLOT LOOKS TO BE
LIMITING THE COVERAGE TO SCT -SHRASN. TO THE W...12Z YPL/INL RAOBS
SHOW A DRIER/MORE STABLE AIRMASS IS PRESENT OVHD TO THE W OF THE
DEFORMATION ZN IN MN...AND THERE IS LTL PCPN FALLING THERE. ALTHOUGH
A FAIRLY IMPRESSIVE COMMA CLD APPEARS ASSOCIATED WITH THE SHRTWV
DIGGING INTO THE NRN PLAINS...PCPN APPEARS TO BE CONFINED TO AN AREA
NEAR LK WINNIPEG RIGHT UNDER THE COMMA HEAD.
MAIN FCST CONCERNS TNGT ARE SN TRENDS/GOING HEADLINES. FOCUS FOR TUE
SHIFTS TO POTENTIAL IMPACT OF SHRTWV DIGGING INTO THE NRN PLAINS.
TNGT...MODELS SHOW SFC LO LIFTING NEWD INTO SE ONTARIO TNGT...BUT
CLOSED LO/DEEPER MSTR TENDING TO LINGER OVER THE UPR LKS DESPITE
ARRIVAL OF DEEP LYR QVECTOR DVGC BY 06Z. AREA OF -SHRASN LIFTING NWD
THRU LK MI AHEAD OF THE UPR LO WL IMPACT THE ERN ZNS THIS EVNG WITH
AREAS OF FOG LINGERING THERE UNTIL SFC LO PASSES TO THE NE THIS EVNG
AND COLDER AIR ARRIVES. SUSPECT LINGERING DEFORMATION ZN PCPN OVER
THE WRN CWA WL SLOWLY DIMINISH WITH ARRIVAL OF THE NEGATIVE
FORCING...SO ENDED THE GOING HEADLINES AS SCHEDULED 00Z TO 06Z FM SW
TO NE. DOWNGRADED THE WARNINGS FOR BARAGA/MQT COUNTIES VALID THRU 0Z
WITH BULK OF PCPN EXPECTED TO FALL FARTHER W ON CYC SIDE OF H7 LO
TRACK. EVEN THOUGH THE STEADY SN WL TEND TO DIMINISH OVER THE
W...CYC NW FLOW OF AIR/ARRIVAL OF COLDER AIR WITH H85 TEMPS PROGGED
TO SINK AS LO AS -14C TO -15C BY 12Z TUE WL CAUSE NMRS SHSN TO
PERSIST. BUT CONCERNED LO INVRN HGTS/DRY MID LVL AIR SHOWN ON THE
12Z INL/YPL RAOBS WL LIMIT THE COVERAGE/INTENSITY OF THE SHSN...SO
WENT NO HIER THAN LIKELY POPS FOR NOW.
TUE...DISTURBANCE MOVING THRU THE NRN PLAINS/ACCOMPANYING DEEP LYR
QVECTOR CNVGC IS PROGGED TO MOVE TOWARD THE CWA...SO MAINTAINED
GOING INCRSG POPS TO CATEGOCIAL NEAR LK SUP BY LATE AFTN WITH FAIRLY
SHARP CYC NW FLOW ACTING AS AN ENHANCEMENT FACTOR IN THE PRESENCE OF
DEEPER MSTR/H85 TEMPS NOT FAR FM -15C. SINCE FCST SDNGS SHOW THE DGZ
SEVERAL THOUSAND FEET DEEP IN THE CONVECTIVE LYR...CONCERNED SOME
ADVY INTENSITY LES MIGHT OCCUR LATER IN THE DAY...ESPECIALLY IN THE
UPSLOPE AREAS OVER THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
WITH AN UPPER LOW JUST E OF THE CWA AT 00Z WED AND A SFC TROUGH OVER
LAKE SUPERIOR...850MB TEMPS WILL BE AROUND -14 WITH CYCLONIC NW-NNW
LOW LEVEL WINDS. THESE CONDITIONS WILL BE FAVORABLE FOR LES TUE
NIGHT...WITH WARMING TEMPS VERY DRY LOW LEVEL AIR MOVING IN WITH A
SFC RIDGE LATE TUE NIGHT INTO WED NIGHT. EXPECT A RELATIVELY QUICK
BURST OF MODERATE LES ALONG AND JUST BEHIND THE SFC TROUGH THAT MAY
BRING A QUICK 2-4 INCHES OF SNOW OVER THE FAVORED HIGHER TERRAIN.
WITH THE RATE THAT THE VERY DRY AIR MOVES IN LATE TUE NIGHT...LES
WILL QUICKLY WEAKEN...AND SHOULD BE ALMOST COMPLETELY GONE BY 15Z
WED /IF NOT A BIT EARLIER/. MODELS THEN INDICATE AN AREA OF
INCREASED LOW LEVEL MOISTURE AND INCREASED LAKE INDUCED EQUILIBRIUM
LEVELS MOVING ACROSS CENTRAL LAKE SUPERIOR ALONG A WEAK SFC TROUGH
WED NIGHT. WILL KEEP SLIGHT CHANCE POPS E OF MARQUETTE AS CONDITIONS
WILL STILL ONLY BE MARGINAL FOR LES. ELSEWHERE WED NIGHT...CLEARING
OVER THE INTERIOR W SHOULD ALLOW MIN TEMPS TO FALL TO NEAR ZERO.
A COUPLE OF SHORTWAVES LOOK TO MOVE NEARBY THU/THU NIGHT...BUT
CONSENSUS OF MODELS PLACES BEST FORCING AND PRECIP N AND S OF THE
CWA...SO WILL KEEP ANY POPS ON THE LOW SIDE.
ANOTHER SHORTWAVE...BACKED UP BY THE LEFT EXIT REGION OF A 120+KT
JET...MOVES THROUGH FRI INTO FRI NIGHT. MODEL VARY WITH TIMING...BUT
GENERALLY AGREE ON OVERALL EXTENT/STRENGTH OF THE SYSTEM. MODELS
PAINT A QUARTER TO A THIRD OF AN INCH OF QPF...AND THE BEST OMEGA
LOOKS TO BE JUST BELOW AND INTO THE DGZ...WHICH SHOULD KEEP SNOW TO
LIQUID RATIOS FROM GETTING TOO LOW. STILL DIFFICULT TO SAY GIVEN
VOLATILE NATURE OF SHORTWAVES THAT FAR OUT...BUT COULD SEE A FEW
INCHES OF SNOW ACROSS THE AREA. 850MB TEMPS AOB -14C AND N-NW FLOW
BEHIND THE SYSTEM WOULD BRING SOME ADDITIONAL LES INTO SAT /AND
POSSIBLY BEYOND BUT TOO UNCERTAIN IN ANY DETAILS THAT FAR OUT TO
MENTION OR ADD TO THE FORECAST/.
HIGHS TEMPS WILL BE IN THE 20S ON WED...WITH A WARM UP TO AROUND 30
ON THU AND INTO THE MID 30S ON FRI. TEMPS LOOK TO DECREASE GOING
INTO THE WEEKEND AND EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 149 PM EDT MON MAR 11 2013
WINTER STORM STILL OVER NORTHERN UPR MICHIGAN...SO EXPECT POOR
FLYING CONDITIONS TO CONTINUE. NNE WINDS TURN NNW TONIGHT. HEAVIER
SNOW WITH MID-LEVEL LOW WILL CONTINUE AT IWD AND CMX INTO THIS
EVENING. THEN...LK EFFECT SNOWS WITH IFR VSBY AND MVFR CIGS SHOULD
CONTINUE THROUGH REST OF TAF PERIOD DUE TO LINGERING COOL AND MOIST
FLOW THROUGH LOWEST 5KFT. AT SAW...CONDITIONS WILL IMPROVE STEADILY
THROUGH LATE AFTN THROUGH TONIGHT AS HEAVIER SNOW REMAINS WEST THIS
AFTN AND LK EFFECT DEVELOPING TONIGHT WILL NOT BE AS FAVORABLE WITH
MORE OF A NW COMPONENT TO WIND. EVEN SO...PLENTY OF LINGERING
MOISTURE AND CYCLONIC LOW-LEVEL WINDS SHOULD RESULT IN MVFR
CONDITIONS INTO TUESDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT MON MAR 11 2013
EXPECT SLOWLY DIMINISHING NNE WINDS TO BACK TO THE NW TNGT INTO TUE
AS SFC LO OVER ERN UPR MI THIS EVNG MOVES NEWD THRU ONTARIO TOWARD
JAMES BAY. EVEN THOUGH WINDS WL BE SLOWLY DIMINISHING...THE ARRIVAL
OF COLDER AIR WL RESULT IN SOME FREEZING SPRAY.
A TROUGH WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT...CAUSING
WINDS TO GUST NEAR 35KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR.
WINDS RELAX WEDNESDAY AND WEDNESDAY NIGHT AS A RIDGE MOVES THROUGH.
BEHIND THE RIDGE. WINDS WILL REMAIN BELOW 20KTS THROUGH THE REST OF
THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MIZ004-
005.
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ002-084.
WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR MIZ003.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLA
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EDT MON MAR 11 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF OVER
CENTRAL AND ERN NAMERICA. NEGATIVELY TILTED CLOSED LO OVER THE LOWER
GRT LKS IS TENDING TO LIFT TO THE NE AS ANOTHER SHRTWV DROPPING THRU
SCENTRAL CANADA DIGS INTO THE NRN PLAINS. THE SFC LO ASSOCIATED WITH
THIS DISTURBANCE HAS PUSHED TO NEAR MANISTIQUE AS OF MID AFTN. SFC
TEMPS AT ISQ/ERY HAVE RISEN INTO THE MID/UPR 30S TO THE E OF THE SFC
LO...AND THERE IS SOME FOG HERE WITH THE DRY AIR MOVING OVER
LINGERING LLVL MSTR. THE ARRIVAL OF THE DRY SLOT ASSOCIATED WITH THE
UPR LO HAS ENDED MOST OF THE PCPN EXCEPT OVER THE WRN COUNTIES...
WHICH LIE UNDER THE DEFORMATION ZN ON THE CYC SIDE OF THE H7 LO
TRACK. PERIODS OF SN HAVE BEEN MOST PERSISTENT IN THESE AREAS
TDAY...WITH SN FALL RATES UP TO 0.5-0.75 INCH/HR. ALTHOUGH THE DRY
SLOT HAS SWEPT THRU THE CNTRL COUNTIES...SOME -SN CONTINUES OVER
MAINLY NCENTRAL MQT COUNTY WITH CYC UPSLOPE N WIND PROVIDING
SUFFICIENT LIFT. ANOTHER AREA OF -SHRASN ASSOCIATED WITH THE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THE UPR LO IS APRCHG THE SE
COUNTIES...BUT PRESENCE OF LARGER SCALE DRY SLOT LOOKS TO BE
LIMITING THE COVERAGE TO SCT -SHRASN. TO THE W...12Z YPL/INL RAOBS
SHOW A DRIER/MORE STABLE AIRMASS IS PRESENT OVHD TO THE W OF THE
DEFORMATION ZN IN MN...AND THERE IS LTL PCPN FALLING THERE. ALTHOUGH
A FAIRLY IMPRESSIVE COMMA CLD APPEARS ASSOCIATED WITH THE SHRTWV
DIGGING INTO THE NRN PLAINS...PCPN APPEARS TO BE CONFINED TO AN AREA
NEAR LK WINNIPEG RIGHT UNDER THE COMMA HEAD.
MAIN FCST CONCERNS TNGT ARE SN TRENDS/GOING HEADLINES. FOCUS FOR TUE
SHIFTS TO POTENTIAL IMPACT OF SHRTWV DIGGING INTO THE NRN PLAINS.
TNGT...MODELS SHOW SFC LO LIFTING NEWD INTO SE ONTARIO TNGT...BUT
CLOSED LO/DEEPER MSTR TENDING TO LINGER OVER THE UPR LKS DESPITE
ARRIVAL OF DEEP LYR QVECTOR DVGC BY 06Z. AREA OF -SHRASN LIFTING NWD
THRU LK MI AHEAD OF THE UPR LO WL IMPACT THE ERN ZNS THIS EVNG WITH
AREAS OF FOG LINGERING THERE UNTIL SFC LO PASSES TO THE NE THIS EVNG
AND COLDER AIR ARRIVES. SUSPECT LINGERING DEFORMATION ZN PCPN OVER
THE WRN CWA WL SLOWLY DIMINISH WITH ARRIVAL OF THE NEGATIVE
FORCING...SO ENDED THE GOING HEADLINES AS SCHEDULED 00Z TO 06Z FM SW
TO NE. DOWNGRADED THE WARNINGS FOR BARAGA/MQT COUNTIES VALID THRU 0Z
WITH BULK OF PCPN EXPECTED TO FALL FARTHER W ON CYC SIDE OF H7 LO
TRACK. EVEN THOUGH THE STEADY SN WL TEND TO DIMINISH OVER THE
W...CYC NW FLOW OF AIR/ARRIVAL OF COLDER AIR WITH H85 TEMPS PROGGED
TO SINK AS LO AS -14C TO -15C BY 12Z TUE WL CAUSE NMRS SHSN TO
PERSIST. BUT CONCERNED LO INVRN HGTS/DRY MID LVL AIR SHOWN ON THE
12Z INL/YPL RAOBS WL LIMIT THE COVERAGE/INTENSITY OF THE SHSN...SO
WENT NO HIER THAN LIKELY POPS FOR NOW.
TUE...DISTURBANCE MOVING THRU THE NRN PLAINS/ACCOMPANYING DEEP LYR
QVECTOR CNVGC IS PROGGED TO MOVE TOWARD THE CWA...SO MAINTAINED
GOING INCRSG POPS TO CATEGOCIAL NEAR LK SUP BY LATE AFTN WITH FAIRLY
SHARP CYC NW FLOW ACTING AS AN ENHANCEMENT FACTOR IN THE PRESENCE OF
DEEPER MSTR/H85 TEMPS NOT FAR FM -15C. SINCE FCST SDNGS SHOW THE DGZ
SEVERAL THOUSAND FEET DEEP IN THE CONVECTIVE LYR...CONCERNED SOME
ADVY INTENSITY LES MIGHT OCCUR LATER IN THE DAY...ESPECIALLY IN THE
UPSLOPE AREAS OVER THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
WITH AN UPPER LOW JUST E OF THE CWA AT 00Z WED AND A SFC TROUGH OVER
LAKE SUPERIOR...850MB TEMPS WILL BE AROUND -14 WITH CYCLONIC NW-NNW
LOW LEVEL WINDS. THESE CONDITIONS WILL BE FAVORABLE FOR LES TUE
NIGHT...WITH WARMING TEMPS VERY DRY LOW LEVEL AIR MOVING IN WITH A
SFC RIDGE LATE TUE NIGHT INTO WED NIGHT. EXPECT A RELATIVELY QUICK
BURST OF MODERATE LES ALONG AND JUST BEHIND THE SFC TROUGH THAT MAY
BRING A QUICK 2-4 INCHES OF SNOW OVER THE FAVORED HIGHER TERRAIN.
WITH THE RATE THAT THE VERY DRY AIR MOVES IN LATE TUE NIGHT...LES
WILL QUICKLY WEAKEN...AND SHOULD BE ALMOST COMPLETELY GONE BY 15Z
WED /IF NOT A BIT EARLIER/. MODELS THEN INDICATE AN AREA OF
INCREASED LOW LEVEL MOISTURE AND INCREASED LAKE INDUCED EQUILIBRIUM
LEVELS MOVING ACROSS CENTRAL LAKE SUPERIOR ALONG A WEAK SFC TROUGH
WED NIGHT. WILL KEEP SLIGHT CHANCE POPS E OF MARQUETTE AS CONDITIONS
WILL STILL ONLY BE MARGINAL FOR LES. ELSEWHERE WED NIGHT...CLEARING
OVER THE INTERIOR W SHOULD ALLOW MIN TEMPS TO FALL TO NEAR ZERO.
A COUPLE OF SHORTWAVES LOOK TO MOVE NEARBY THU/THU NIGHT...BUT
CONSENSUS OF MODELS PLACES BEST FORCING AND PRECIP N AND S OF THE
CWA...SO WILL KEEP ANY POPS ON THE LOW SIDE.
ANOTHER SHORTWAVE...BACKED UP BY THE LEFT EXIT REGION OF A 120+KT
JET...MOVES THROUGH FRI INTO FRI NIGHT. MODEL VARY WITH TIMING...BUT
GENERALLY AGREE ON OVERALL EXTENT/STRENGTH OF THE SYSTEM. MODELS
PAINT A QUARTER TO A THIRD OF AN INCH OF QPF...AND THE BEST OMEGA
LOOKS TO BE JUST BELOW AND INTO THE DGZ...WHICH SHOULD KEEP SNOW TO
LIQUID RATIOS FROM GETTING TOO LOW. STILL DIFFICULT TO SAY GIVEN
VOLATILE NATURE OF SHORTWAVES THAT FAR OUT...BUT COULD SEE A FEW
INCHES OF SNOW ACROSS THE AREA. 850MB TEMPS AOB -14C AND N-NW FLOW
BEHIND THE SYSTEM WOULD BRING SOME ADDITIONAL LES INTO SAT /AND
POSSIBLY BEYOND BUT TOO UNCERTAIN IN ANY DETAILS THAT FAR OUT TO
MENTION OR ADD TO THE FORECAST/.
HIGHS TEMPS WILL BE IN THE 20S ON WED...WITH A WARM UP TO AROUND 30
ON THU AND INTO THE MID 30S ON FRI. TEMPS LOOK TO DECREASE GOING
INTO THE WEEKEND AND EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 149 PM EDT MON MAR 11 2013
WINTER STORM STILL OVER NORTHERN UPR MICHIGAN...SO EXPECT POOR
FLYING CONDITIONS TO CONTINUE. NNE WINDS TURN NNW TONIGHT. HEAVIER
SNOW WITH MID-LEVEL LOW WILL CONTINUE AT IWD AND CMX INTO THIS
EVENING. THEN...LK EFFECT SNOWS WITH IFR VSBY AND MVFR CIGS SHOULD
CONTINUE THROUGH REST OF TAF PERIOD DUE TO LINGERING COOL AND MOIST
FLOW THROUGH LOWEST 5KFT. AT SAW...CONDITIONS WILL IMPROVE STEADILY
THROUGH LATE AFTN THROUGH TONIGHT AS HEAVIER SNOW REMAINS WEST THIS
AFTN AND LK EFFECT DEVELOPING TONIGHT WILL NOT BE AS FAVORABLE WITH
MORE OF A NW COMPONENT TO WIND. EVEN SO...PLENTY OF LINGERING
MOISTURE AND CYCLONIC LOW-LEVEL WINDS SHOULD RESULT IN MVFR
CONDITIONS INTO TUESDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT MON MAR 11 2013
EXPECT SLOWLY DIMINISHING NNE WINDS TO BACK TO THE NW TNGT INTO TUE
AS SFC LO OVER ERN UPR MI THIS EVNG MOVES NEWD THRU ONTARIO TOWARD
JAMES BAY. EVEN THOUGH WINDS WL BE SLOWLY DIMINISHING...THE ARRIVAL
OF COLDER AIR WL RESULT IN SOME FREEZING SPRAY.
A TROUGH WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT...CAUSING
WINDS TO GUST NEAR 35KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR.
WINDS RELAX WEDNESDAY AND WEDNESDAY NIGHT AS A RIDGE MOVES THROUGH.
BEHIND THE RIDGE. WINDS WILL REMAIN BELOW 20KTS THROUGH THE REST OF
THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MIZ004-
005.
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ002-084.
WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR MIZ003.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLA
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1100 AM EDT MON MAR 11 2013
.UPDATE...
ISSUED AT 1059 AM EDT MON MAR 11 2013
12Z RAOBS/LATEST STLT IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
OVER SW WI LIFTING NEWD AS DISTURBANCE DIGS INTO THE NRN PLAINS. DRY
SLOT IN ADVANCE OF THIS DISTURBANCE HAS OVERSRPEAD MUCH OF THE
SCNTRL AND ERN CWA...LIMITING THE PCPN IN THESE AREAS TO SCT -SHSN
OR EVEN -SHRA OVER THE E WHERE SFC TEMPS ARE NOW ABV 32. BUT WET SN
STRETCHING FM SE MN THRU WCENTRAL WI INTO THE W HALF OF UPR MI ON
CYC SIDE OF H7 LO TRACK.
A FEW CHGS TO HEADLINES FOR NOW...PLAN TO CANX GOING WRNG FOR ALGER
COUNTY AS DRY SLOT HAS LIFTED THRU THIS AREA. ALTHOUGH THERE COULD
BE SOME SN OVER THE FAR W PORTION OF THE COUNTY...BULK OF THIS AREA
WL SEE ONLY SCT -SHSN THRU THE DAY. MQT COUNTY WL BE ON THE ACYC
SIDE OF THE H7 LO TRACK AS WELL...BUT PERSISTENT NE SFC WIND IS
FVRBL FOR LINGERING WET SN OVER THE HIER TERRAIN. WL CONT GOING
HEADLINES FOR THE WRN ZNS...WHICH WL BE MOST IMPACTED BY SN UNDER
THE DEFORMATION ZN.
SINCE TEMPS ARE ABV 32 WHERE RA IS FALLING OVER THE E FM NEWBERRY TO
MANISTIQUE...TOOK OUT MENTION OF FZRA. ALSO ADDED MENTION OF PATCHY
FOG WITH LLVL MSTR UNDER THE DRY SLOT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT MON MAR 11 2013
UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER SOUTHERN
IOWA WITH AN ASSOCIATED TROUGH OVER THE CENTRAL PLAINS. THIS
CLOSED LOW WILL CONTINUE TO HEAD NORTHEAST TODAY AND OPEN UP. THIS
TROUGH WILL THEN TAKE ON A NEGATIVE TILT OVER THE UPPER GREAT LAKES.
THIS TROUGH MOVES OUT TONIGHT.
NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA
WITH DEEP MOISTURE TODAY BEFORE THE STRONG Q-VECTOR CONVERGENCE
MOVES OUT BY TONIGHT. NAM HAS SOME ISENTROPIC LIFT ON I280OK-I295K
WITH MOISTURE THIS MORNING THAT MOVES OUT BY THIS EVENING.
BUSY MORNING DEALING WITH ALL SORTS OF WEATHER AND MIXED PCPN. HEAVY
SNOW CONTINUES ACROSS THE CENTRAL AND WESTERN CWA WITH SOME RAIN
MIXED IN WITH SOME FREEZING RAIN OVER THE SOUTH AND EAST. LEAD
SHORTWAVE ON WATER VAPOR IS MOVING THROUGH AND THERE IS A BREAK IN
PCPN THAT IS DEVELOPING ACROSS NE WI AND THE FAR SOUTHERN U.P.
ASSOCIATED WITH A DRY SLOT. THIS DRY SLOT IS HEADING NORTH AND COULD
END UP ENDING THE PCPN SOONER THAN EXPECTED EXCEPT IN UPSLOPE AREAS.
AM A LITTLE CONCERNED THAT THE DRY SLOT WOULD HAVE SOME FREEZING
DRIZZLE ASSOCIATED WITH IT. FOR THIS REASON...KEPT UP ALL HEADLINES
FOR NOW AND WILL PROBABLY HAVE TO CANCEL SOME OF THEM EARLIER IF IT
APPARENT THAT THE HEAVIEST PCPN IS DONE ALREADY. OTHERWISE...KEPT IN
FREEZING RAIN AND RAIN THIS MORNING ACROSS THE SOUTH AND EAST WITH
SNOW IN THE WEST AND QUICKLY LOOKED AT A FEW SOUNDINGS FOR ISQ...ESC
AND ERY OFF OF BUFKIT AND CONFIRMED PREVIOUS THINKING OF MIXED PCPN
THIS MORNING. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE
PREVIOUS FORECAST EXCEPT PUSH TIMING UP FOR HEAVIER PCPN MOVING OUT
THIS MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 509 AM EDT MON MAR 11 2013
LOW PRESSURE SYSTEM THAT WILL BE AFFECTING THE AREA TODAY AND
TONIGHT WILL BE EXITING THROUGH NORTHWEST QUEBEC ON TUESDAY...BUT
WILL LINGER A SURFACE TROUGH BACK TO THE SOUTHEAST ACROSS UPPER
MICHIGAN. THIS...COMBINED WITH THE UPPER TROUGH OVER THE AREA WILL
LEAD TO LAKE EFFECT/ENHANCED SNOW SHOWERS OVER THE AREA ON TUESDAY
INTO TUESDAY NIGHT. 850MB TEMPS AROUND -13C TO -16C WILL PROVIDE
ENOUGH OVER LAKE INSTABILITY AND WHEN COMBINED WITH THE DEEPER
MOISTURE LINGERING UNDER THE UPPER TROUGH OVER THE GREAT LAKES
REGION WILL LEAD TO THE HEAVIEST SNOW IN THE NORTH-NORTHWEST WIND
SNOW BELTS. LATEST TRENDS IN THE MODELS ARE INDICATING THE DRIER AIR
ALOFT TO BE A LITTLE FARTHER WEST FOR TUESDAY AND THINK THERE WILL
BE A BETTER CHANCE FOR SNOW OVER THE WESTERN PORTIONS OF THE CWA
THAN PREVIOUS THOUGHT. WITH THE GREATER CONFIDENCE ON THE SNOW ON
TUESDAY...HAVE BUMPED POPS NEAR LAKE SUPERIOR TO DEFINITE VALUES
WITH THE HIGHEST POPS OVER THE KEWEENAW AND NORTH CENTRAL UPPER
MICHIGAN. FARTHER INLAND...WOULD EXPECT SCATTERED SNOW SHOWERS WITH
THE ABUNDANT MOISTURE AND CONTINUING UPWARD MOTION UNDER THE UPPER
TROUGH...ESPECIALLY ON TUESDAY AFTERNOON. SNOWFALL AMOUNTS DURING
THE DAY ON TUESDAY WILL BE IN THE 1-4 INCH RANGE ACROSS MUCH OF THE
AREA...WITH THE HIGHEST AMOUNTS OVER THE FAVORED LOCATIONS NEAR LAKE
SUPERIOR. IN ADDITION...INCREASING WINDS AND A TREND TOWARDS MORE
FLUFFY SNOW SHOULD LEAD TO BLOWING SNOW FOR AREAS NEAR LAKE SUPERIOR
TUESDAY AFTERNOON INTO TUESDAY TONIGHT. THESE TWO FACTORS MAY BE
ENOUGH FOR A FUTURE ADVISORY FOR THE COUNTIES NEAR LAKE SUPERIOR AND
WILL MENTION THE LIGHT/MODERATE SNOW IN THE HWO.
WITH THE UPPER TROUGH STARTING TO SHIFT TO THE EAST ON TUESDAY NIGHT
AND INTO WEDNESDAY...DRIER AIR WILL START TO WORK INTO THE UPPER
GREAT LAKES AREA AND DECREASE THE INTENSITY OF THE SNOW SHOWERS.
COMPARED TO 24HRS AGO...THE MODELS HAVE SHOWN A MUCH QUICKER DRYING
TREND AND HAVE FOLLOWED SUIT WITH POPS. LATEST IDEA FROM THE NAM/GFS
IS FOR THE LAKE EFFECT SNOW TO BE DONE BY WEDNESDAY AFTERNOON. THERE
MAY BE A FEW SNOW SHOWERS REDEVELOPING OVER THE EAST LATE IN THE
AFTERNOON OR EARLY EVENING AS THERE ARE HINTS OF A SECOND AREA OF
925-850MB MOISTURE MOVING THROUGH WITH FAVORABLE 850MB TEMPS OF
-13C.
THE UPPER RIDGE WILL PUSH IN ON WEDNESDAY NIGHT AND ALLOW A SURFACE
HIGH TO MOVE INTO THE AREA. ANY ISOLATED SNOW SHOWERS ON WEDNESDAY
EVENING SHOULD QUICKLY COME TO AN END AS THE SMALL POCKET OF
MOISTURE DEPARTS. WITH THE DRY AIR AND WEAKENING WINDS WITH THE
APPROACHING HIGH...HAVE TRENDED TEMPS COLDER ON WEDNESDAY NIGHT.
CURRENT FORECAST HAS INTERIOR WEST TEMPS IN THE LOW SINGLE DIGITS
AND THERE IS THE POTENTIAL FOR SOME LOCATIONS TO FALL BELOW BELOW
ZERO.
WITH AN UPPER RIDGE OVER THE WESTERN CONUS...AREA WILL BE UNDER
NORTHWEST FLOW ALOFT FROM THURSDAY THROUGH THE WEEKEND. THIS LEADS
TO THE POTENTIAL FOR SHORTWAVES AND WEAK LOW PRESSURE SYSTEMS TO
QUICKLY SLIDE ACROSS THE AREA. THERE ARE STILL HINTS OF A SHORTWAVE
FOR THE THURSDAY INTO THURSDAY NIGHT...BUT LATEST TRENDS HAVE THAT
SLIDING TO THE SOUTHWEST OF THE CWA. BASED OFF THE 00Z RUNS...THE
BEST POTENTIAL FOR A SHORTWAVE TO AFFECT THE AREA WILL BE ON
SATURDAY AND WILL TREND TOWARDS CHANCE POPS FOR THAT PERIOD.
HIGHS TUESDAY AND WEDNESDAY WILL BE SIMILAR TO VALUES YOU WOULD
EXPECT TO SEE A MONTH AGO /MID 20S/. THERE WILL BE A SLIGHT WARM UP
FOR THE SECOND HALF OF THE WEEK AND INTO THE WEEKEND...BUT HIGHS
SHOULD STILL STAY AT OR SLIGHTLY BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 714 AM EDT MON MAR 11 2013
WINTER STORM TRACKING INTO THE UPPER GREAT LAKES WILL CONTINUE TO BE
THE DOMINANT FEATURE FOR MOST OF THIS FCST PERIOD. ON THE WESTERN
FRINGE OF THE STORM SYSTEM...IFR CONDITIONS SHOULD PREVAIL AT KIWD
THRU THE MORNING HRS BEFORE CONDITIONS IMPROVE TO MVFR THROUGH THE
REST OF THE PERIOD THERE. HEAVIER SNOW WILL IMPACT KCMX AND
ESPECIALLY KSAW...LIKELY RESULTING IN IFR CONDITIONS THRU MUCH OF
THE MORNING HRS. N/NE WINDS GUSTING 20-30KT...STRONGEST AT KSAW
GIVEN FAVORABLE WIND DIRECTION...WILL PRODUCE BLSN AS WELL. THIS
AFTN...EXPECT SOME IMPROVEMENT TO MVFR AT KCMX/KSAW WHERE THINGS
WILL STAY THROUGH TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT MON MAR 11 2013
DECIDED TO GO WITH A GALE WARNING FOR EASTERN LAKE SUPERIOR THIS
MORNING AS THE SFC PRESSURE GRADIENT TIGHTENS AS A LOW MOVES THROUGH
NORTHERN LAKE MICHIGAN INTO NORTHERN LAKE HURON TODAY. FREQUENT
GUSTS UP TO 35 KNOTS WILL BE EXPECTED THIS MORNING. WINDS CRANK UP
AGAIN TO CLOSE TO GALES ACROSS EASTERN LAKE SUPERIOR TUE NIGHT.
AFTER THAT...HIGH PRESSURE BUILDS IN AND THE WINDS WILL DIMINISH
THROUGH THE REST OF THE FORECAST PERIOD. THERE WILL BE SOME FREEZING
SPRAY OUT ON LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ004-005-
084.
WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...SRF
AVIATION...07
MARINE...07
AREA FORECAST DISCUSSION
NWS DULUTH MN
317 PM CDT MON MAR 11 2013
.SHORT TERM...CWA REMAINS UNDER THE INFLUENCE OF A CYCLONIC
CIRCULATION TO THE EAST OF THE REGION. ORGANIZED FORCING IN THE
FORM OF WEAK FRONTOGENESIS HAS KEPT MORE PERSISTENT SNOW OVER ERN
EDGE OF REGION. ELSEWHERE...ABUNDANT CLOUD COVER AND A FEW
FLURRIES ARE OCCURRING.
TONIGHT...AN AMPLIFYING MID LVL SYSTEM WILL TRACK FROM SRN
MANITOBA TO JUST SOUTH OF THE BRD LAKES VICINITY. IT IS DIFFICULT
TO FIND MUCH IN THE WAY OF A SFC REFLECTION ASSOCIATED WITH THIS
FEATURE EITHER IN THE PRESSURE OR WIND FIELDS. USED A BLEND OF THE
SREF AND EC TO KEEP POPS FOCUSED IN TWO AREAS. FIRST...ACROSS THE
SRN TIER OF ZONES CLOSER TO TRACK OF UPPER FEATURE. SECOND...AS
COLDER AIR MOVES ACROSS LAKE SUPERIOR...SOME INCREASE IN LES MAY
OCCUR OVER ERN WISC SNOWBELTS.
TOMORROW...UPPER LOW SCOOTS QUICKLY SE OF REGION BY MIDDAY WITH
DEEPENING OF NRLY FLOW ACROSS CWA. MOST PROBABLE AREAS FOR PRECIP
WILL BE OVER ARROWHEAD AND WISC SNOWBELTS. A WRAPAROUND LOBE OF
DEEP LAYER MOISTURE ASSOCIATED WITH A MIGRATORY SHORTWAVE TROF
WILL ROTATE WESTWARD INTO ARROWHEAD DURING THE DAY. THIS IS
REFLECTED IN THE EC AND THE SPC WRF/NMM. 85H THERMAL TROUGH
SETTLES SOUTHWARD ACROSS LAKE SUPERIOR IN THE AFTERNOON. NEARLY
UNIDIRECTIONAL FLOW IN SFC/85H LAYER COMBINED WITH INCREASINGLY
FAVORABLE SYNOPTIC SCALE MOISTURE WILL PROMOTE ADDITIONAL SNOW
INTO SNOWBELTS. MAY NEED TO CONSIDER AN ADVISORY FOR LATE
AFTERNOON INTO EVENING.
TUESDAY NIGHT THROUGH MONDAY.
THE NORTHLAND WILL CONTINUE TO BE INFLUENCED BY A TROUGH TUESDAY
NIGHT...WITH SOME LIGHT SNOW OR FLURRIES WILL LINGERING TUESDAY
EVENING...BUT DIMINISHING OVERNIGHT. LITTLE ACCUMULATION IS EXPECTED
FOR MOST AREAS. THE EXCEPTION WILL BE ALONG THE SOUTH SHORE...MAINLY
THE SNOWBELT REGION OF ASHLAND/IRON COUNTIES. CHANCES FOR LAKE
EFFECT SNOW SHOWERS LOOK PRETTY GOOD WITH NORTHERLY WINDS AND 850MB
TEMPERATURES DROPPING TO AROUND -14C TO -16C. WE INCREASED POPS AND
SNOW AMOUNTS ACROSS ASHLAND/IRON COUNTIES TUESDAY NIGHT...WITH THE
BEST CHANCE FROM 00Z WED TO ABOUT 09Z WED. INVERSION LEVELS DROP
LATE AND DRIER AIR MOVES OVER THE LAKE LATE TUESDAY NIGHT AND
THROUGH WEDNESDAY. WINDS WILL ALSO BACK WEDNESDAY. AN ADVISORY MAY
BE NEEDED FOR IRON AND ASHLAND COUNTIES.
A WEST NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE REST OF
PERIOD WITH SEVERAL SHORTWAVES MOVING THROUGH AND BRINGING PERIODIC
CHANCES FOR PRECIPITATION. MOST OF THE SHORTWAVES WILL ONLY BRING
LIGHT PRECIPITATION.
WE HAVE A CHANCE FOR LIGHT SNOW WEDNESDAY NIGHT INTO THURSDAY AS WAA
MOVES THROUGH THE AREA. THE PRECIP LOOKS RATHER LIGHT...AND PRECIP
TYPE COULD BE IN QUESTION. 850MB TEMPS ARE FORECAST TO RISE TO
AROUND +4C OVER OUR SOUTHWEST ZONES BY 00Z FRI...AND REMAIN AROUND
-4C FAR NORTHEAST. FORECAST SOUNDINGS ALSO SHOW THE MOIST LAYER IS
RATHER LIMITED...WITH ICE CRYSTAL PRESENCE IN QUESTION. LATER SHIFTS
MAY HAVE TO ADD SOME MIXED PRECIP ONCE WE GET CLOSER.
A MORE SIGNIFICANT CLIPPER SYSTEM IS FORECAST BY THE ECMWF TO AFFECT
THE NORTHLAND FRIDAY INTO FRIDAY NIGHT...WITH THE GFS ABOUT 12 HOURS
FASTER. A MIX COULD BE POSSIBLE ONCE AGAIN...ESPECIALLY OVER THE
SOUTHERN HALF. A FEW INCHES OF SNOW WILL BE POSSIBLE WITH THIS
SYSTEM. THE GFS SHOWS THE CORE OF THE PRECIPITATION FURTHER NORTH
THAN THE ECMWF. BOTH THE GFS AND ECMWF DO SHOW COLDER AIR MOVING IN
BEHIND THIS CLIPPER...LASTING INTO THE WEEKEND.
HIGH TEMPERATURES WILL RANGE FROM THE UPPER TWENTIES TO LOWER
THIRTIES WEDNESDAY. THEY WILL WARM INTO THE LOWER TO MID THIRTIES
THURSDAY/FRIDAY...AND COOL A BIT BEHIND THE CLIPPER OVER THE WEEKEND.
.AVIATION...18Z TAFS
MIX OF MVFR AND LOW VFR CONDITIONS COVERED THE NORTHLAND EARLY
THIS AFTERNOON...WITH SOME LIGHT SNOW OR FLURRIES IN SPOTS.
OVERALL...WE EXPECT THESE CONDITIONS TO CONTINUE THROUGH THE
PERIOD. THE RUC 900-925MB PRESSURE DEFICITS WERE INDICATING SOME
DECREASE IN CLOUD COVER THIS EVENING...BUT JUST DON`T HAVE THE
CONFIDENCE TO DIMINISH CEILINGS TOO MUCH. A CLIPPER MAY SPREAD
ADDITIONAL CLOUDS AND PERHAPS SOME ADDITIONAL LIGHT SNOW TO THE
REGION TONIGHT.
.POINT TEMPS/POPS...
DLH 15 29 11 30 / 20 30 10 0
INL 11 27 6 29 / 20 20 10 0
BRD 16 29 10 30 / 30 30 10 10
HYR 16 30 12 32 / 30 60 20 10
ASX 16 29 15 30 / 30 60 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CANNON
LONG TERM....MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
123 PM CDT MON MAR 11 2013
.AVIATION...18Z TAFS
MIX OF MVFR AND LOW VFR CONDITIONS COVERED THE NORTHLAND EARLY
THIS AFTERNOON...WITH SOME LIGHT SNOW OR FLURRIES IN SPOTS.
OVERALL...WE EXPECT THESE CONDITIONS TO CONTINUE THROUGH THE
PERIOD. THE RUC 900-925MB PRESSURE DEFICITS WERE INDICATING SOME
DECREASE IN CLOUD COVER THIS EVENING...BUT JUST DON`T HAVE THE
CONFIDENCE TO DIMINISH CEILINGS TOO MUCH. A CLIPPER MAY SPREAD
ADDITIONAL CLOUDS AND PERHAPS SOME ADDITIONAL LIGHT SNOW TO THE
REGION TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 1009 AM CDT MON MAR 11 2013/
UPDATE...INCREASED SKY COVERAGE ACROSS MOST OF THE ERN CWA WITH
SLOWER CLEARING TREND INDICATED BY SAT IMAGERY. AREA OF CLEARING
OVER WRN CWA MAY BE SHORT LIVED AS MID LVL MOISTURE FROM NEXT
SYSTEM IS APPROACHING WRN BORDER ALREADY. FLURRIES WILL REMAIN
NEAR TWIN PORTS UNTIL MIDDAY WHEN RELAXING OF CIRCULATION FROM ERN
SYSTEM BEGINS. BDRY LYR FLOW BACKS MORE NRLY THIS AFTERNOON OVER
WISCONSIN. INCREASED POPS OVER ERN WISC ZONES REMAINDER OF MORNING
AS LATEST SPC MESOANALYSIS...AND 88D RETURNS...SHOWS A DEFORMATION
AXIS STRETCHING ACROSS PRICE COUNTY. WILL INCREASE SNOW
ACCUMULATIONS TO 1 TO 3 INCHES.
PREV DISCUSSION... /ISSUED 307 AM CDT MON MAR 11 2013/
SHORT TERM...TODAY AND TONIGHT. THE MAIN FOCUS FOR THE SHORT
TERM IS THE SNOW IN EASTERN AREAS OF THE NW WI FORECAST AREA.
CURRENT SURFACE AND RADAR ANALYSIS INDICATE MODERATE SNOW FALLING
ACROSS AREAS EAST OF A LINE FROM IRONWOOD THROUGH GLIDDEN. VSBYS
HAVE RANGED FROM 1/2 TO 1 MILE AT PBH AND IRONWOOD THE PAST TWO
HOURS. NAM HAD HAD MORE SNOWFALL WITH SYSTEM THAN THE GFS/ECMWF
BUT THE SREF HAS BEEN CLOSER THE PAST COUPLE OF RUNS WITH
PLACEMENT. AS INDICATED BY PREVIOUS SHIFT...THE NAM CROSS
SECTIONS SHOW GOOD SATURATION/UPWARD MOTION IN THE DENDRITIC EARLY
THIS MORNING THROUGH 12Z. IT WILL BE CLOSE...BUT SOME AREA IN
SOUTHERN PRICE COUNTY COULD SEE 6 INCHES. THE OTHER COUNTIES IN
THE ADVISORY HAVE SOME SNOW BANDS OVER THEM SO THE 3-5 INCHES LOOK
GOOD. WILL KEEP CURRENT HEADLINES UP THROUGH 17Z AS PLANNED. THE
SNOW WILL TAPER OFF TO LIGHT SNOW BY EARLY THIS AFTERNOON AS THE
LOW MOVES OFF TO THE NORTHEAST. WILL ALSO HAVE FLURRIES IN THE
REST OF FCST AREA THIS MORNING AS SFC OBS HAVE BEEN REPORTING THEM.
EXTENDED...TUESDAY THROUGH MONDAY. IT IS LOOKING A BIT DRIER FOR
TUESDAY NOW THAN IT HAS OVER THE PAST SEVERAL RUNS. THE MODELS
GENERALLY AGREE ON FAIRLY DRY AIR ENTRAINMENT INTO THE CWA BEHIND
DEPARTING LOW PRESSURE. THE BEST CHANCE OF LIGHT SNOW WOULD BE ALONG
THE SOUTH SHORE OF LAKE SUPERIOR. ANOTHER STRONGER SHORTWAVE SHOULD
MOVE GENERALLY SOUTH OF THE CWA TUESDAY AND TUESDAY NIGHT. HIGH
PRESSURE WILL BUILD IN ON WEDNESDAY BRINGING A BIT OF SUNSHINE TO
THE NORTHLAND. ANOTHER SHOT OF LIGHT SNOW IS POSSIBLE ON THURSDAY
BUT ONLY LOW POPS WARRANTED FOR RELATIVELY WEAK WAA EVENT. A BETTER
SNOWFALL EVENT IS EXPECTED TO ARRIVE ON FRIDAY AND LINGER INTO
SATURDAY AND EVEN A BIT INTO SATURDAY NIGHT. HAVE RAISED POPS INTO
THE HIGH CHANCE CATEGORY BUT WILL LIKELY NEED TO CONTINUE TO TREND
TOWARD A LIKELY TYPE WORDING. COOL HIGH PRESSURE WILL THEN BUILD IN
FOR THE REMAINDER OF THE WEEKEND WITH SOME SCATTERED LIGHT SNOW
SHOWERS BY MONDAY. OVERALL WE ARE LOOKING AT TEMPERATURES IN THE 30S
FOR THE MOST PART...WITH SOME 40S LATE IN THE WEEK AND INTO THE
UPCOMING WEEKEND. SHOULD BE A GOOD RUN OF DAYTIME MELTING AND
NIGHTTIME COOLING WHICH WOULD BE GOOD FOR SPRING SNOWMELT ISSUES.
&&
.POINT TEMPS/POPS...
DLH 15 29 12 31 / 20 20 10 0
INL 11 27 8 30 / 20 20 10 0
BRD 16 29 11 30 / 30 30 10 10
HYR 16 30 13 33 / 30 30 20 10
ASX 16 29 16 31 / 30 40 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
331 AM CDT MON MAR 11 2013
.DISCUSSION...
WILL SEE A GOOD COOLDOWN FOR THE START OF THE WEEK BEHIND
SHORTWAVE CURRENTLY DROPPING SOUTHEAST THROUGH SASKATCHEWAN. THAT
FEATURE HELPS CARVE OUT A NICE TROUGH FROM OUR AREA THROUGH THE
GREAT LAKES REGION BY TUESDAY... WITH CYCLONIC FLOW AND BELOW
NORMAL TEMPERATURES LIKELY BRINGING SOME SNOW SHOWER ACTIVITY
GIVEN THE EASE WITH WHICH WE CAN GENERATE STEEP LOW LEVEL LAPSE
RATES NOW. AFTER THAT... THE LARGE SCALE PATTERN LOOKS TO MODERATE
OVER THE SECOND HALF OF THE WEEK... WITH NORTHWEST FLOW GIVING WAY
TO MORE IN THE WAY OF RIDGING AND WESTERLY DOWNSLOPING FLOW FROM
THE ROCKIES. THAT COULD BRING SOME CHANCES FOR MIXED PCPN DURING
THE END OF THE WEEK INTO THE WEEKEND... ALTHOUGH THERE CERTAINLY
DON/T APPEAR TO BE ANY SIGNIFICANT SYSTEMS ON THE HORIZON. FOR
SIGNIFICANCE... ATTENTION IS STILL SOMEWHAT FIXED ON THE SHORT
TERM... ALTHOUGH THAT IS BECOMING LESS INTERESTING AS WELL. RADAR
TRENDS OVER THE PAST FEW HOURS HAVE DIMINISHED MARKEDLY AS UPPER
RIDGING ENCROACHES FROM THE WEST AND THE UPPER WAVE TO OUR SOUTH
HAS SHEARED OUT AND OPENED UP A BIT. THE HIGH RESOLUTION
GUIDANCE... INCLUDING THE HRRR... LOCAL WRF-ARW... AND THE
HOPWRF... ALL DID A NICE JOB OF SHOWING THE RAPID WEAKENING
TREND... AND GENERALLY AGREE THAT ANY SIGNIFICANT PCPN IS DONE FOR
THE AREA. HOWEVER... A NARROW BAND WILL LIKELY HANG ON INTO THE
MORNING HOURS FROM FAR SOUTHEAST MINNESOTA THROUGH OUR FAR EASTERN
COUNTIES. THE AFOREMENTIONED HIGH RESOLUTION SOLUTIONS ALSO
SUGGEST A SLIGHT REJUVENATION OF ACTIVITY IN THAT AREA IN THE
12-15Z TIME FRAME... SO LOCATIONS FROM NEAR EAU CLAIRE SOUTH AND
EASTWARD COULD STILL SEE SOME ADDITIONAL LIGHT ACCUMULATIONS. THAT
BEING SAID... PLAN TO DROP MOST OF THE HEADLINES BY 09Z... LEAVING
ONLY THINGS OVER THE FAR EAST.
COULD SEE SOME FLURRIES OR SNOW SHOWERS LINGER OVER PORTIONS OF
THE AREA TONIGHT... MAINLY THE NORTH HALF... WHERE CYCLONIC FLOW
WILL LINGER AND THE SECONDARY SHORTWAVE AND TROUGH WILL ARRIVE
LATE TONIGHT. THAT FEATURE WILL HELP KEEP CYCLONIC BOUNDARY LAYER
FLOW IN PLACE THROUGH THE DAY ON TUESDAY AND GIVEN THE SHARPLY
COOLER TEMPERATURES ALOFT THAT IT BRINGS INTO THE AREA... THINK WE
SHOULD SEE A FAIR AMOUNT OF SCATTERED SNOW SHOWER ACTIVITY DURING
THE DAY ON TUESDAY. THINGS THEN LOOK TO BE FAIRLY QUIET THROUGH
WEDNESDAY... WITH THE NEXT CHANCE OF PCPN HOLDING OFF UNTIL
THURSDAY WHEN WE SEE RETURN FLOW AND DECENT WARM ADVECTION SETUP
ACROSS THE REGION. AT THIS POINT IT LOOKS LIKE THE EASTERN AND
NORTHERN FORECAST AREA HAVE THE BEST SHOT AT SEEING ANY OF THIS
WARM ADVECTION PCPN GIVEN WHERE THINGS APPEAR TO SATURATE ALONG
THE ISENTROPIC SURFACES. ANY PCPN ON THURSDAY SHOULD STILL BE IN
THE FORM OF SNOW. A BETTER SHOT AT SEEING SOME PCPN ACROSS THE
AREA WILL COME FROM FRIDAY INTO THE WEEKEND AS THE BAROCLINIC ZONE
SETS UP ACROSS THE AREA AND A FEW SHORTWAVES RIPPLE EAST-SOUTHEAST
ALONG IT. THE MAIN IMPULSE LOOKS TO SWING ACROSS THE AREA LATE
FRIDAY INTO EARLY SATURDAY... BUT THAT IS AROUND THE TIME WHEN THE
ECMWF AND GFS START TO EXHIBIT SIGNIFICANT DIFFERENCES IN THE
LARGE SCALE FLOW ACROSS THE CONTINENT... SO THERE IS CERTAINLY A
FAIR AMOUNT OF UNCERTAINTY AT THIS POINT. INCLUDED SOME POPS FOR
MUCH OF THE TIME FROM FRIDAY THROUGH SUNDAY... ALTHOUGH WITH THE
POSSIBILITY OF MIXED PCPN GIVEN THE FORECAST SOUNDINGS AND GENERAL
WARM ADVECTION PATTERN.
&&
.AVIATION.../06Z TAF ISSUANCE/
/ISSUED 1158 PM CDT SUN MAR 10 2013/
HEAVY SNOW WELL UNDER WAY FROM SOUTH CENTRAL MN UP INTO WRN WI.
HOWEVER...ONLY EAU WILL HAVE TO DEAL WITH THE BRUNT OF THE SNOW...
WITH SNOW BAND MAKING IT NO FURTHER THAN ABOUT 5-10 MILES FROM
MSP. BASED ON RAP/NAM HOURLY SNOWFALL FORECASTS...HEAVIEST SNOW
HAPPENING NOW...WITH 1/2SM TYPE SNOW NOT LASTING MUCH PAST 7Z.
WILL HAVE TO WATCH FOR A SECOND BAND OF HEAVIER SNOW FROM ABOUT
12Z TO 15Z AS MAIN UPPER LOW MOVES INTO CENTRAL WI. THE HRRR HAS
BEEN BACK AND FORTH WITH WHERE THIS BAND SETS UP BETWEEN EAU AND
BCK...SO JUST LEFT GENERAL MVFR VIS -SN DURING THE MORNING...BUT
DEPENDING ON WHERE THIS SECOND BAND SETS UP...THERE COULD BE
ANOTHER BOUT OF IFR OR LOWER VIS THERE. EVERYWHERE ELSE IT IS A
CIG PROBLEM. AXN HAS FOUND ITSELF JUST WEST OF THE LOW CLOUDS AND
IT SHOULD STAY THERE THROUGH MONDAY AFTERNOON. FOR OTHER
TERMINALS...HEIGHTS SHOULD BE FAIRLY CONSTANT THROUGH THE NIGHT.
SHOULD SEE SOME BREAKS BY MORNING...WITH CATEGORICAL IMPROVEMENTS
IN CIGS ACROSS MN BY THE AFTERNOON...BUT THERE IS THE POSSIBILITY
THAT ERN MN REMAINS IN MVFR CIGS THROUGH THE DURATION OF THE TAF
PERIOD. TOWARD THE END OF THE TAF PERIOD...STRONG WAVE CURRENTLY
UP IN ALBERTA WILL DIVE SE INTO MN ON NW FLOW. THIS WILL BRING
MVFR CIGS BACK TO WRN MN AFTER 00Z AND THEY WILL BE CLOSE TO
AXN/RWF BY THE END OF THIS TAF PERIOD.
KMSP...CONFIDENCE IS HIGH THAT FIELD REMAINS IN THE FRONT ROW
SEATS WITH ONGOING SNOW STORM JUST TO THE SE. FLIGHTS ON APPROACH
FOR THE 12S WILL LIKELY BE COMING THROUGH SNOW ON THEIR WAY
IN...BUT NOT EXPECTING ANYTHING WORSE THAN A FEW FLURRIES FOR THE
FIELD. CIGS WILL BE FLIRTING WITH 017 THROUGH THE REST OF
TONIGHT...BUT THEY SHOULD REMAIN ABOVE THIS LEVEL. CONFIDENCE IS
LOW IN CLEARING TOMORROW AFTERNOON...WITH IT VERY PLAUSIBLE THAT
MVFR CIGS NEVER BECOME BETTER THAN BKN BEFORE CLOUDS FROM NW
SYSTEM SHOW UP. FOR WINDS...SPEEDS WILL BE FAIRLY CONSISTENT IN
THE 10-15 KT RANGE WITH A SLOW BACKING TOWARD THE WEST THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS POSSIBLE WITH -SN. NW WIND 15G25KTS.
WED...VFR. NW WIND 5 TO 10 KTS BACKING TO SW.
THU...VFR. S WIND AROUND 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 4 AM CDT EARLY THIS MORNING FOR
FARIBAULT-FREEBORN-GOODHUE-STEELE-WASECA.
WINTER WEATHER ADVISORY UNTIL 4 AM CDT EARLY THIS MORNING FOR
BLUE EARTH-MARTIN-RICE.
WI...WINTER STORM WARNING UNTIL 4 AM CDT EARLY THIS MORNING FOR DUNN-
PIERCE.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR CHIPPEWA-
EAU CLAIRE-PEPIN.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR RUSK.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1158 PM CDT SUN MAR 10 2013
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 854 PM CDT SUN MAR 10 2013/
WINTER STORM BEGINNING TO TAKE SHAPE THIS EVENING AS SFC LOW MOVES
INTO THE QUAD CITIES. LAST FEW RUNS OF THE RAP HAVE BEEN REALLY
UNLOADING WITH HEAVY SNOW FROM CENTRAL FARIBAULT COUNTY...UP TO
OWATONNA...LAKE CITY...AND EAU CLAIRE/CHIP FALLS. WITH THE RAP AND
HRRR COMING IN A BIT FARTHER NW WITH THE HEAVIER SNOW...TACKED ON
A FEW MORE COUNTIES TO THE WARNING...WITH SLIGHTLY HIGHER AMOUNTS
EXPECTED AS WELL IN THE ALBERT LEA AND EAU CLAIRE AREAS.
CURRENT RADAR SHOWING A RATHER STRONG BAND SETTING UP FROM NEAR
THE CITY OF BLUE EARTH UP TOWARD LAKE CITY. AT TIMES HAVE SEEN
KAEL AND KTOB GO DOWN TO A HALF MILE VIS WITH THIS BAND
OVERHEAD...AND A CALL TO FARIBAULT COUNTY REVEALED 2 INCHES ALREADY
IN THE CITY OF BLUE EARTH. BASED ON THE RAP/SPC MESO
ANALYSIS...THIS LOOKS TO BE THE RESULT OF A COMBO OF FGEN AROUND
THE H85 LAYER...ALONG WITH STRONG MOISTURE TRANSPORT WITHIN THE
COLD CONVEYOR BELT TO THE NORTH OF THE SFC LOW. THIS IS HEAVIER
BAND 1 OF 2 THAT THE RAP HAS FOR SE MN...WITH TOTAL QPF FROM BLUE
EARTH...UP THROUGH DODGE CENTER...LAKE CITY...AND EAU CLAIRE
BETWEEN 0.85" AND 0.95"...WHICH RESULTS IN A FAIRLY HEALTHY REGION
OF 8 TO 10 INCHES OF SNOW.
BAND 2 MENTIONED ABOVE SETS UP JUST EAST OF THE FIRST BAND LATER
TONIGHT AND WILL PRIMARILY IMPACT THE ARX AREA. THIS BAND IS
ASSOCIATED WITH PV ADVECTION TO THE WEST OF THE MAIN PV ANOMALY
WHICH THE RAP TAKES FROM AROUND IOWA CITY UP TOWARD WAUSAU. THE
11.23 RAP HAS SLIGHTLY HIGHER QPF AMOUNTS UP AROUND 1 INCH IN THIS
AREA...WHICH WOULD INDICATE THE POTENTIAL FOR AMOUNTS OF A FOOT OR
MORE.
WHAT MAKES THIS A TRICKY SYSTEM TO FORECAST IS THE VERY TIGHT
GRADIENT IN SNOWFALL AND AMOUNTS THAT IS EXPECTED TO THE NORTHWEST
OF THE HEAVY BAND OF SNOW. FOR INSTANCE...ACROSS GOODHUE
COUNTY...LATEST UPDATE TO GRIDS HAS AROUND 8 INCHES ALONG THE
WABASHA COUNTY LINE IN THE SOUTH...WITH AMOUNTS NEAR 4 INCHES
ALONG THE DAKOTA COUNTY LINE TO THE NORTH. WITH THE SLIGHT
NORTHWESTWARD SHIFT IN THE HEAVIER SNOW AMOUNTS...THIS PULLED THE
6+ INCH AMOUNTS A LITTLE FARTHER NORTHWEST. FOR THE COUNTIES ADDED
/WASECA...STEELE...GOODHUE...PIERCE...DUNN...AND CHIPPEWA WI/...IT
IS BASICALLY THE SOUTHEAST HALF OR LESS OF THESE COUNTIES WHERE
AMOUNTS OF 6 INCHES OR MORE ARE EXPECTED. WITH THE TIGHT GRADIENT
IN SNOW...DID NOT SEE THE NEED TO ADD ANY COUNTIES TO AN ADVY. FOR
EXAMPLE...IN DAKOTA COUNTY...HAVE SNOWFALL AMOUNTS RANGING FROM A
TRACE ALONG THE HENNEPIN/RAMSEY COUNTY LINE TO NEAR 4 INCHES ALONG
THE GOODHUE COUNTY LINE. OTHER COUNTIES BORDERING THE WARNING SHOW
SIMILAR GRADIENTS...SO DID NOT ADD ANY COUNTIES TO AN ADVY. IF
ANYTHING...COUNTIES STILL IN THE ADVY WILL BE CLOSE TO WARNING
TYPE SNOWS IN THE FAR SOUTHEAST TIPS OF THOSE COUNTIES. KIND OF AN
ALL OR NOTHING SCENARIO HERE!
WILL BE SEEING SOME INTENSE SNOWFALL RATES TONIGHT ON THE ORDER OF
1 TO 2 INCHES PER HOUR AS WELL /SEE NESDIS SATELLITE PRECIP
ESTIMATE PRODUCT AND SPC MESO DISCUSSION #269/. BY MONDAY
MORNING...THE INTENSE SNOWFALL WILL START LETTING UP...WITH LIGHT
SNOW LINGERING INTO THE AFTERNOON...ESPECIALLY ACROSS WI. SNOW
WILL LIKELY CONTINUE BEYOND CURRENT END TIME OF HEADLINES...THOUGH
ACCUMULATING SNOWS SHOULD BE ALL BUT DONE BY NOON...BUT A POSSIBLE
EXTENSION IN TIME WILL NEED TO BE CONSIDERED BY LATER SHIFTS.
BEHIND THIS SYSTEM...IT WILL BE COOL THROUGH THE MIDDLE OF THE
WEEK AS HIGH PRESSURE SETTLES IN. TUESDAY LOOKS TO BE THE COLDEST
DAY NEXT WEEK. WITH THE COLD UPPER TROUGH OVERHEAD...THIS WILL
CREATE STEEP LAPSE RATES WITH DAYTIME HEATING AND LIKELY SOME
BOUTS OF SNOW SHOWERS...THOUGH NO ACCUMULATIONS ARE EXPECTED.
FOR THE SECOND HALF OF THE WEEK...A MODERATION IN TEMPERATURES BACK
TOWARD NORMAL /WHICH ARE ALREADY PUSHING 40 ON THE HIGHS/ IS
EXPECTED AS UPPER RIDGING BUILDS EAST FROM THE ROCKIES.
FOR NEXT WEEKEND AND BEYOND...THERE IS NOT MUCH CONFIDENCE IN THE
FORECAST AS THE ECMWF AND THE GFS SIT ABOUT 180 DEGS APART FROM
EACH OTHER. FOR NEXT WEEKEND INTO THE FOLLOWING WEEK...THE ECMWF
HAS THE DEEP THROUGH OVER ERN NOAM...WITH A SHARP RIDGE OVER THE
ROCKIES...WHICH OPENS THE DOOR FOR MORE MODIFIED ARCTIC AIR. THE
GFS ON THE OTHER HAND GOES RIDGING EAST AND TROUGHING WEST AND
BRINGS ANOTHER WARM WET SYSTEM INTO THE UPPER MS VALLEY AT THE END
OF NEXT WEEKEND INTO THE FOLLOWING WEEK. BASED ON PAST
PERFORMANCE...THE GFS IS LIKELY A BIT TOO AGGRESSIVE WITH BREAKING
DOWN THE WRN RIDGE NEXT WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
HEAVY SNOW WELL UNDER WAY FROM SOUTH CENTRAL MN UP INTO WRN WI.
HOWEVER...ONLY EAU WILL HAVE TO DEAL WITH THE BRUNT OF THE SNOW...
WITH SNOW BAND MAKING IT NO FURTHER THAN ABOUT 5-10 MILES FROM
MSP. BASED ON RAP/NAM HOURLY SNOWFALL FORECASTS...HEAVIEST SNOW
HAPPENING NOW...WITH 1/2SM TYPE SNOW NOT LASTING MUCH PAST 7Z.
WILL HAVE TO WATCH FOR A SECOND BAND OF HEAVIER SNOW FROM ABOUT
12Z TO 15Z AS MAIN UPPER LOW MOVES INTO CENTRAL WI. THE HRRR HAS
BEEN BACK AND FORTH WITH WHERE THIS BAND SETS UP BETWEEN EAU AND
BCK...SO JUST LEFT GENERAL MVFR VIS -SN DURING THE MORNING...BUT
DEPENDING ON WHERE THIS SECOND BAND SETS UP...THERE COULD BE
ANOTHER BOUT OF IFR OR LOWER VIS THERE. EVERYWHERE ELSE IT IS A
CIG PROBLEM. AXN HAS FOUND ITSELF JUST WEST OF THE LOW CLOUDS AND
IT SHOULD STAY THERE THROUGH MONDAY AFTERNOON. FOR OTHER
TERMINALS...HEIGHTS SHOULD BE FAIRLY CONSTANT THROUGH THE NIGHT.
SHOULD SEE SOME BREAKS BY MORNING...WITH CATEGORICAL IMPROVEMENTS
IN CIGS ACROSS MN BY THE AFTERNOON...BUT THERE IS THE POSSIBILITY
THAT ERN MN REMAINS IN MVFR CIGS THROUGH THE DURATION OF THE TAF
PERIOD. TOWARD THE END OF THE TAF PERIOD...STRONG WAVE CURRENTLY
UP IN ALBERTA WILL DIVE SE INTO MN ON NW FLOW. THIS WILL BRING
MVFR CIGS BACK TO WRN MN AFTER 00Z AND THEY WILL BE CLOSE TO
AXN/RWF BY THE END OF THIS TAF PERIOD.
KMSP...CONFIDENCE IS HIGH THAT FIELD REMAINS IN THE FRONT ROW
SEATS WITH ONGOING SNOW STORM JUST TO THE SE. FLIGHTS ON APPROACH
FOR THE 12S WILL LIKELY BE COMING THROUGH SNOW ON THEIR WAY
IN...BUT NOT EXPECTING ANYTHING WORSE THAN A FEW FLURRIES FOR THE
FIELD. CIGS WILL BE FLIRTING WITH 017 THROUGH THE REST OF
TONIGHT...BUT THEY SHOULD REMAIN ABOVE THIS LEVEL. CONFIDENCE IS
LOW IN CLEARING TOMORROW AFTERNOON...WITH IT VERY PLAUSIBLE THAT
MVFR CIGS NEVER BECOME BETTER THAN BKN BEFORE CLOUDS FROM NW
SYSTEM SHOW UP. FOR WINDS...SPEEDS WILL BE FAIRLY CONSISTENT IN
THE 10-15 KT RANGE WITH A SLOW BACKING TOWARD THE WEST THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS POSSIBLE WITH -SN. NW WIND 15G25KTS.
WED...VFR. NW WIND 5 TO 10 KTS BACKING TO SW.
THU...VFR. S WIND AROUND 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR FARIBAULT-
FREEBORN-GOODHUE-STEELE-WASECA.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR BLUE EARTH-
MARTIN-RICE.
WI...WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR CHIPPEWA-DUNN-
EAU CLAIRE-PEPIN-PIERCE.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT MONDAY FOR RUSK.
&&
$$
MPG/MPG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
634 PM CDT TUE MAR 12 2013
.AVIATION...
00Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. BKN SC DECK AT ALL
3 SITES WILL BE EXITING THIS EVENING...FIRST AT LNK AND THEN OFK
AND OMA BY AROUND 07Z. SOME SCT FLURRIES REMAIN POSSIBLE AT OMA
FOR ANOTHER HOUR OR TWO...BUT NO ACCUMULATION IS EXPECTED. THE
WINDS WILL ALSO BE DIMINISHING THIS EVENING WITH HIGH PRESSURE
MOVING OVER. WINDS WILL INCREASE FROM THE AND SOUTHWEST ON
WEDNESDAY WITH SOME MID LEVEL CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT TUE MAR 12 2013/
SHORT TERM...TONIGHT THROUGH FRIDAY.
MOSTLY CLOUDY CONDITIONS HAD DEVELOPED THROUGH THE DAY IN THE
NORTHEASTERN 2/3 OF THE FORECAST AREA...WITHIN AN AREA CYCLONIC
NORTHWESTERLY FLOW AROUND STRONG CLOSED LOW PRESSURE ACROSS THE
WESTERN GREAT LAKES. A FEW FLURRIES HAD DEVELOPED IN NORTHEAST
NEBRASKA AND NORTHWEST IOWA...BUT MORE IMPORTANTLY...WINDS GUSTING
30 TO 35 MPH HAS ALSO CREATED AREAS OF BLOWING SNOW OUT IN OPEN
RURAL AREAS. THIS WAS CREATING SOME VISIBILITY ISSUES...AS WELL
AS SOME SLICK ROADWAYS. THIS TREND WILL CONTINUE THROUGH EARLY
EVENING UNTIL THE WINDS BEGIN TO DIMINISH BY 5 TO 7 PM...ALTHOUGH
ISOLATED FLURRIES COULD STILL BE POSSIBLE IN WESTERN IOWA FOR
ANOTHER HOUR OR TWO BEYOND THAT. CLOUD TRENDS OVERNIGHT WILL BE
ALSO BE TRICKY TO FORECAST. SURFACE HIGH PRESSURE RIDGE WILL
CONTINUE MOVING IN FROM THE WEST. THIS WILL ALLOW SOME OF THE
DIURNAL CLOUDS TO DISSIPATE ON THE SOUTHWEST EDGE...HOWEVER AS
WITH PAST SEVERAL SYSTEMS...THE RAP SEEMS TO HAVE A MUCH BETTER
HANDLE ON THE LOW LEVEL CLOUDINESS...LINGERING IT MUCH LONGER THAN
OTHER MODELS WOULD SUGGEST. THIS COULD ALSO AFFECT HOURLY
TEMPERATURES...AS SKIES CLEAR IN SOME AREAS AND WINDS BECOME LIGHT
AND PERHAPS EVEN CALM IN OUR WESTERN CWA. SOME CIRRUS COULD ALSO
BEGIN TO MOVE INTO THESE SAME AREAS TOWARD DAYBREAK...AS AREAS
ALONG/EAST OF THE MISSOURI RIVER FINALLY BEGIN TO SCATTER OUT.
SOUTHEASTERLY SURFACE FLOW DEVELOPS ON WEDNESDAY AS THE MID/HIGH
CLOUDS MOVE ACROSS THE REGION. TEMPS SHOULD WARM INTO THE MID 30S
OVER THE SNOWFIELD, AND THE LOWER/MID 40S ELSEWHERE.
MEANWHILE...WARM AIR ADVECTION ALOFT WILL CONTINUE THROUGH THE
REMAINDER OF THE PERIOD. ANOTHER WEAK CLIPPER SYSTEM WILL MOVE
THROUGH THE DAKOTAS WEDNESDAY NIGHT. WHILE THIS COULD GENERATE A
SPRINKLE OR TWO IN OUR AREA AND MAYBE EVEN MEASURABLE PRECIP JUST
TO OUR NORTH/NORTHEAST...WILL MAINTAIN A DRY FORECAST AT THIS
TIME WITH PARTLY TO MOSTLY CLOUDY SKIES EXPECTED. THIS SHOULD
TRANSLATE TO DECENT WARMING ON THURSDAY...UPPER 40S OVER THE
DIMINISHING SNOW PACK...WHICH IS STILL UNDER MAV/MET GUIDANCE...
TO THE LOWER 60S OVER THE SNOW FREE AREAS. FRIDAY SHOULD BE THE
WARMEST DAY OF THE WEEK AS TEMPERATURES WARM SIGNIFICANTLY AHEAD
OF THE NEXT COLD FRONT EXPECTED FOR THE WEEKEND. TEMPS FRIDAY
SHOULD REACH THE MID 50S WHERE SOME SNOW STILL EXISTS...AND EVEN
IN THE MID TO UPPER 60S ELSEWHERE.
DEWALD
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
THE EXTENDED PERIOD LOOKS TO BE A PERIOD OF BELOW NORMAL
TEMPERATURES WITH UNSETTLED WEATHER SATURDAY THROUGH MONDAY. WEATHER
DISTURBANCES MOVING THROUGH THE WEST AND NORTHWEST FLOW ALOFT AND
WILL BRING CHANCES OF PRECIPITATION. THE LONG RANGE MODELS ARE NOT
IN GOOD AGREEMENT IN SPECIFIC TIMING AND STRENGTH OF THE
SYSTEMS...THUS LOW CONFIDENCE IN PINNING DOWN THE THERMAL STRUCTURE
AND TIMING. A WEAK WAVE APPEARS TO MOVE THROUGH THE CENTRAL/NORTHER
PLAINS SATURDAY AND SATURDAY NIGHT...AND THE GFS LINGERS IT INTO
SUNDAY...WITH SNOW...SLEET...AND RAIN POSSIBLE. SUNDAY NIGHT INTO
MONDAY...ANOTHER STRONGER SYSTEM MOVES THROUGH. THE EC IS STRONGER
WITH THE WAVE...FARTHER NORTH WITH THE PRECIP AND MOVES IT THROUGH
FASTER WITH MORE COLD AIR AND STRONGER WINDS AVAILABLE. FOR NOW HAVE
CHANCE POPS FOR RAIN OR SNOW MENTIONED FOR SUNDAY NIGHT AND MONDAY.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1242 PM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 1107 AM CDT MON MAR 11 2013
INCREASED MAX TEMPERATURES TODAY ACROSS MY SOUTHEAST ZONES INTO
THE UPPER 40S. TEMPERATURES HAVE QUICKLY WARMED THIS MORNING IN
AREAS OF MINIMAL SNOW COVER. DID NOT TAKE AN AGGRESSIVE APPROACH
WITH CONTINUED WARMING THIS AFTERNOON SINCE NORTHWEST WINDS WILL
MOVE OVER THE DENSE SNOW PACK FROM OGA TO VTN...WHICH MAY HAMPER
TEMPERATURES BY A FEW DEGREES.
ALSO ADJUSTED POP FIELDS FOR THIS AFTERNOON AND EVENING. H7 FRONT
SHOWING UP WELL ON IR SATELLITE...EXTENDING FROM CENTRAL MONTANA
SOUTHEAST INTO NORTHEAST COLORADO. EXPECT THIS TO BE THE PRIMARY FOCUS
FOR SNOW SHOWERS LATER TODAY INTO THE OVERNIGHT HOURS AS COLDER
AIR MOVES SOUTH IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY IN
EASTERN MONTANA.
UPDATE ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON MAR 11 2013
NO AVIATION CONCERNS OVER THE NEXT 24 HOURS. CONDITIONS WILL
REMAIN VFR ACROSS MOST OF WESTERN NEBRASKA. SNOW SHOWERS WILL BE
POSSIBLE IN THE EASTERN PANHANDLE AND FAR SOUTHWEST NEBRASKA THIS
EVENING AND TONIGHT...WHICH MAY CLIP KLBF. DUE TO LOW FORECASTER
CONFIDENCE HAVE LEFT ANY MENTION OF -SN OUT OF THE TAF FOR NOW.
MONITORING POSSIBILITY OF FOG AT KVTN OVERNIGHT ON TOP OF FRESH
SNOW PACK. HOWEVER WINDS ARE EXPECTED TO REMAIN ELEVATED THROUGH
THE OVERNIGHT HOURS WHICH WOULD ALL BUT ELIMINATE CHANCES OF FOG
FORMATION. TRENDS WILL BE MONITORED AND AMENDMENTS WILL BE MADE IF
NECESSARY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MARTIN
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1108 AM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 1107 AM CDT MON MAR 11 2013
INCREASED MAX TEMPERATURES TODAY ACROSS MY SOUTHEAST ZONES INTO
THE UPPER 40S. TEMPERATURES HAVE QUICKLY WARMED THIS MORNING IN
AREAS OF MINIMAL SNOW COVER. DID NOT TAKE AN AGGRESSIVE APPROACH
WITH CONTINUED WARMING THIS AFTERNOON SINCE NORTHWEST WINDS WILL
MOVE OVER THE DENSE SNOW PACK FROM OGA TO VTN...WHICH MAY HAMPER
TEMPERATURES BY A FEW DEGREES.
ALSO ADJUSTED POP FIELDS FOR THIS AFTERNOON AND EVENING. H7 FRONT
SHOWING UP WELL ON IR SATELLITE...EXTENDING FROM CENTRAL MONTANA
SOUTHEAST INTO NORTHEAST COLORADO. EXPECT THIS TO BE THE PRIMARY FOCUS
FOR SNOW SHOWERS LATER TODAY INTO THE OVERNIGHT HOURS AS COLDER
AIR MOVES SOUTH IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY IN
EASTERN MONTANA.
UPDATE ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 620 AM CDT MON MAR 11 2013
VFR IS GENERALLY EXPECTED TODAY AND TONIGHT AS A MIX OF MID AND
HIGH CLOUDS MOVE SOUTHEAST OFF THE HIGH PLAINS. THERE IS
OPPORTUNITY FOR MVFR CIGS IN ISOLATED TO SCATTERED RAIN AND SNOW
SHOWERS...MAINLY LATE THIS AFTERNOON AND THIS EVENING ACROSS NRN
AND WRN NEB. THE MODELS OFFER SOME DIVERSE SOLNS TO THIS EVENT.
SOME DEVELOP CONVECTION ACROSS NRN NEB AROUND NOON WHILE OTHERS
WAIT TILL LATE AFTERNOON AND SOME SOLNS SHOW NO CONVECTION AT ALL
ACROSS NRN NEB.
THERE IS A GOOD CONSENSUS FOR ACTIVITY DEVELOPING OFF THE BLACK
HILLS LATE THIS AFTERNOON AND ACROSS THE NEB PANHANDLE. THIS
ACTIVITY WILL MOVE SOUTH SOUTHEAST. IN FACT THERE COULD EVEN BE AN
ISOLATED LIGHTNING STRIKE OR TWO ACROSS SHERIDAN AND CHERRY
COUNTIES LATE THIS AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MARTIN
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
724 AM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 620 AM CDT MON MAR 11 2013
VFR IS GENERALLY EXPECTED TODAY AND TONIGHT AS A MIX OF MID AND
HIGH CLOUDS MOVE SOUTHEAST OFF THE HIGH PLAINS. THERE IS
OPPORTUNITY FOR MVFR CIGS IN ISOLATED TO SCATTERED RAIN AND SNOW
SHOWERS...MAINLY LATE THIS AFTERNOON AND THIS EVENING ACROSS NRN
AND WRN NEB. THE MODELS OFFER SOME DIVERSE SOLNS TO THIS EVENT.
SOME DEVELOP CONVECTION ACROSS NRN NEB AROUND NOON WHILE OTHERS
WAIT TILL LATE AFTERNOON AND SOME SOLNS SHOW NO CONVECTION AT ALL
ACROSS NRN NEB.
THERE IS A GOOD CONSENSUS FOR ACTIVITY DEVELOPING OFF THE BLACK
HILLS LATE THIS AFTERNOON AND ACROSS THE NEB PANHANDLE. THIS
ACTIVITY WILL MOVE SOUTH SOUTHEAST. IN FACT THERE COULD EVEN BE AN
ISOLATED LIGHTNING STRIKE OR TWO ACROSS SHERIDAN AND CHERRY
COUNTIES LATE THIS AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
930 PM EDT TUE MAR 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS TONIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 930 PM TUESDAY...
THROUGH TONIGHT: SKIES HAVE CLEARED ACROSS ALL OF CENTRAL NC AS THE
COLD FRONT WHICH BROUGHT TODAY`S RAIN HAS SHIFTED TO COASTAL
SECTIONS AND IS POISED TO MOVE OFFSHORE... PROPELLED BY COOL HIGH
PRESSURE EXTENDING FROM CENTRAL CANADA DOWN THROUGH THE PLAINS AND
LOWER MISS VALLEY. THE DIFFERENCE BETWEEN THE 00Z SOUNDINGS AT MHX
(SOME LINGERING MOISTURE BELOW 850 MB) AND GSO (VERY DRY AIR THROUGH
THE COLUMN) TELLS THE STORY... AS DOES THE WATER VAPOR IMAGERY
SHOWING WELL THE SLUG OF DRY AIR SWEEPING TO THE NE THROUGH CENTRAL
NC. UPPER LEVEL TRAJECTORIES DO SUGGEST HOWEVER THAT THE HIGH CLOUDS
NOW STREAMING ACROSS ARK AND THE MEMPHIS AREA WILL SWEEP ACROSS NC
TOWARD MIDNIGHT AND DURING THE OVERNIGHT HOURS... ALSO INDICATED BY
THE RAP SOUNDINGS. WILL INCLUDE A THIN VEIL OF CLOUDS OVERNIGHT...
BUT OTHERWISE SKIES SHOULD BE CLEAR. AS THE SURFACE RIDGE BUILDS IN
OVERNIGHT WITH NORTHEASTERLY SURFACE WINDS AND COLD AIR ADVECTION...
THICKNESSES ARE EXPECTED TO PLUMMET... FROM MUCH ABOVE NORMAL
READINGS TODAY TO JUST BELOW NORMAL READINGS BY MORNING... ALTHOUGH
THE MORE SIGNIFICANT DROP COMES WEDNESDAY INTO WEDNESDAY NIGHT WITH
THE ARRIVAL OF THE POLAR FRONT. BOTH TEMPS AND DEW POINTS ARE
TRENDING VERY CLOSE TO THE FORECAST PACE... AND LOWS OF 34-42 STILL
LOOK REASONABLE. -GIH
WEDNESDAY AND WEDNESDAY NIGHT: POTENT SHORTWAVE ENERGY UPSTREAM OVER
MINNESOTA WILL DIG SOUTHEAST INTO THE TN VALLEY TONIGHT AND THEN
THROUGH THE CAROLINAS AND VIRGINIA ON WEDNESDAY. AS THE POTENT
VORTMAX SWINGS THROUGH THE AREA...STRONG DCVA AIDED BY COOLING ALOFT
WILL RESULT IN STRONG MID AND UPPER LEVEL ASCENT. AIRMASS WILL BE
TOO DRY TO SUPPORT OTHER THAN A PERIOD OF A PERIOD OF BROKEN TO
OVERCAST MID CLOUDS WEDNESDAY AFTERNOON. AN ATYPICALLY COLD AIRMASS
ALOFT (H85 TEMPS 1-2 STD DEVIATIONS BELOW NORMAL)IN THE PRESENCE OF
DEEP VERTICAL MIXING WILL RESULT IN BELOW NORMAL TEMPERATURES WITH
BREEZY NWLY WIND GUSTS BETWEEN 20 TO 25KTS. BOTH THE DRY-ADIABATIC
AND LOW-LEVEL THICKNESS TEMPERATURES SCHEME SUGGEST AFTERNOON HIGHS
A GOOD 5 TO 8 DEGREES BELOW STATISTICAL MOS GUIDANCE.
HOWEVER...CONSIDERING THE EVER INCREASING SUN ANGLE THIS TIME OF
YEAR...AM CONCERNED CURRENT FORECAST MAY BE A TOUCH TOO COOL...BUT
THE EXPECTED PERIOD OF BROKEN MID-LEVEL CLOUD COVER SHOULD HELP.
HIGHS NEAR 50 NW TO MID/UPPER 50S SOUTHEAST.
A SECONDARY ROUND OF LOW-LEVEL COLD ADVECTION WILL OCCUR WEDNESDAY
EVENING/NIGHT IN ASSOCIATION WITH RENEWED LOW-LEVEL NWLY FLOW
IN THE WAKE OF THE EXITING UPPER LEVEL TROUGH. MINS FOR THE SECOND
CONSECUTIVE NIGHT WILL BE DRIVEN BY CAA. LOWS WED NIGHT IN THE UPPER
20S TO LOWER 30S. -CBL
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 PM TUESDAY...
A STRONG UPPER LEVEL TROUGH WILL STILL BE IN PLACE ALONG THE EASTERN
US ON THURSDAY. THIS...ALONG WITH CONTINUED COLD AIR ADVECTION
(NORTHWESTERLY WINDS OF 10-15 MPH WILL LEAD TO ANOTHER DAY OF BELOW
NORMAL TEMPS. HIGHS ARE ONLY EXPECTED TO BE IN THE LOW 50S (POSSIBLY
STRUGGLING TO EVEN REACH 50 DEGREES IN SOME LOCATIONS). THE UPPER
LEVEL TROUGH AXIS WILL MOVE OFFSHORE THURSDAY NIGHT...BUT A
DISTURBANCE WITHIN THE NORTHWEST FLOW ALOFT WILL MOVE SOUTHEASTWARD
ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. IT STILL
APPEARS THE MAIN IMPACT FROM THIS FEATURE WILL BE AN INCREASE IN MID
LEVEL CLOUD COVER AS THE BOUNDARY LAYER IS PROGGED TO BE RATHER DRY.
HOWEVER...CANNOT COMPLETELY SOME SPRINKLES OR A LIGHT SHOWER...
ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA. DESPITE
CLOUD COVER...OVERNIGHT LOWS WILL GENERALLY BE WITHIN A DEGREE OR
TWO OF FREEZING. CLOUDS WILL DECREASE THROUGHOUT THE DAY ON FRIDAY
AS SUBSIDENCE INCREASES ON THE BACKSIDE OF THE DEPARTING SHORTWAVE.
AS HEIGHTS INCREASE SOME...TEMPS WILL BEGIN TO MODERATE...WITH
HIGHS IN THE MID/UPPER 50S AND OVERNIGHT LOWS IN THE MID/UPPER 30S
EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 320 PM TUESDAY...
UNCERTAINTY REMAINS HIGH DURING THE LONG TERM PERIOD. OVERALL...THE
FLOW ALOFT IS PROGGED TO DEAMPLIFY AND TEMPS SHOULD GRADUALLY MODIFY
THROUGH THE WEEKEND. MODELS ARE STILL INDICATING A BACKDOOR FRONT
MOVING INTO THE AREA ON SATURDAY...BUT THERE IS CONSIDERABLE
DISAGREEMENT ON HOW TO HANDLE THIS FRONT. THE LAST COUPLE OF RUNS OF
THE GFS PUSH THE FRONT SOUTH OF THE AREA SATURDAY NIGHT...WHILE THE
ECMWF STALLS THE FRONT SOMEWHERE NEAR THE FORECAST AREA. THIS
CREATES A LOT OF DISAGREEMENT WITH RESPECT TO BOTH PRECIP CHANCES
AND TEMPS. THEN MODELS SHOW A WAVE OF LOW PRESSURE DEVELOPING ON THE
FRONT SUNDAY INTO MONDAY AND TRACKING EAST...ALTHOUGH WHERE EXACTLY
THIS FRONT WILL BE (AND ASSOCIATED LOW TRACK) IS STILL IN QUESTION.
MODELS ARE THEN IN GENERAL AGREEMENT WITH A MORE AMPLIFIED TROUGH
ALOFT MOVING INTO THE MIDWEST ON TUESDAY...WITH AN ASSOCIATED
SURFACE FRONT PROGGED TO CROSS THE REGION TUESDAY/TUESDAY NIGHT.
GIVEN ALL THE UNCERTAINTY WILL NOT CHANGE THE FORECAST TOO
MUCH...WITH SLIGHT CHANCE POPS OVER THE WEEKEND...BEFORE SLIGHTLY
HIGHER POPS FOR EARLY NEXT WEEK. TEMPS ARE EXPECTED TO BE ABOVE
NORMAL ON SATURDAY (AHEAD OF THE BACKDOOR FRONT)...WITH NEAR NORMAL
TEMPS FOR THE REMAINDER OF THE PERIOD (ALTHOUGH IT WILL BE HIGHLY
DEPENDENT ON FRONTAL POSITION).
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM TUESDAY...
CLEAR SKIES AND A STEADY 5-10KT NORTHWESTERLY WIND ARE EXPECTED
OVERNIGHT BETWEEN A COLD FRONT MOVING OFFSHORE AND AN UPPER LEVEL
DISTURBANCE APPROACHING FROM THE NORTHWEST. VFR CONDITIONS ARE
EXPECTED TO CONTINUE ON WEDNESDAY AS THE UPPER DISTURBANCE CROSSES
THE AREA...THOUGH STRONG WESTERLY WINDS WILL GUST TO NEAR 25KT
DURING THE AFTERNOON.
OUTLOOK...
GUSTY NORTHWESTERLY WINDS ARE EXPECTED AGAIN ON THURSDAY...FOLLOWED
BY A PASSING UPPER DISTURBANCE EARLY FRIDAY AND A VERY SMALL CHANCE
OF A SHOWER. VFR CONDITIONS ARE EXPECTED TO PREVAIL. LATER IN THE
WEEKEND...A COLD FRONT IS FORECAST TO SLIP SOUTH INTO CENTRAL NC AND
LINGER THROUGH EARLY NEXT WEEK...BRING A CHANCE OF SUB-VFR
CONDITIONS BY SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...HARTFIELD/CBL
SHORT TERM..KRR
LONG TERM...KRR
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
358 PM EDT MON MAR 11 2013
.SYNOPSIS...
A SLOW-MOVING COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND
TUESDAY AND MOVE OFFSHORE TUESDAY NIGHT. HIGH PRESSURE WILL BUILD
IN FROM THE WEST WEDNESDAY AND LINGER ACROSS THE AREA BEFORE MOVING
OFFSHORE ON SATURDAY. ANOTHER COLD FRONT WILL APPROACH THE REGION
SUNDAY AND MOVE OFFSHORE BY MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 330 PM MONDAY...AFTER A VERY WARM AFTERNOON WITH HIGH
TEMPERATURES AT OR ABOVE 70 DEGREES AT MANY LOCATIONS...CLOUDS
WILL INCREASE OVERNIGHT AS LOW-LEVEL MOISTURE IS ADVECTED INTO THE
REGION WITH A INCREASING SE SURFACE FLOW. THE CLOUDS AND WINDS
SHOULD HOLD MINIMUM TEMPERATURES IN THE MILD MIDDLE AND UPPER 50S
TONIGHT. THE 4KM WRF...ARW AND RAP MODELS KEEP MOST OF THE
SIGNIFICANT PRECIPITATION WEST OF OUR CWA THROUGH ABOUT
MIDNIGHT...ALTHOUGH A FEW LIGHT WARM ADVECTION LIGHT SHOWERS OR
SPRINKLES MAY OCCUR LATER THIS EVENING.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS OF 330 PM MON...THERE IS STILL SOME CONCERN ON TUESDAY ABOUT A
MINIMAL THREAT OF SEVERE WEATHER IN A WINDOW DURING THE MORNING
AND EARLY AFTERNOON. STRONG LOW-LEVEL SSE/S WINDS ARE EXPECTED
WITH GOOD LOW-LEVEL SHEAR VALUES AND THE AREA IN A RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET STREAK. LOW LEVEL (0-3 KM) HELICITY
VALUES ARE FORECAST TO BE AS HIGH AS 300 M2/S2 DURING THE EARLY
PART OF TUESDAY...HOWEVER CAPE VALUES LOOK TO MINIMAL WITH
FORECAST LI`S OF ONLY ABOUT -1 PER FORECAST SOUNDINGS. THINK THE
THREAT OF ANY THUNDER ENDS DURING THE MID-AFTERNOON AS THE COLD
FRONT MOVES OFFSHORE IN THE EARLY EVENING. LOOKS LIKE MOST AREAS
WILL RECEIVE ROUGHLY ONE HALF INCH OF RAIN TUESDAY. TEMPERATURES
WILL RISE INTO THE MIDDLE 60S TO LOWER 70S FOR HIGHS ON TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 300 PM MONDAY...MED RANGE MODELS IN DECENT AGREEMENT THROUGH
FRIDAY...THEN DIVERGE FOR SAT-MON. INITIAL SHRT WV AND ASSCTD SFC
FRONT WILL MOVE OFFSHORE TUE EVENING...FOLLOWED BY DRIER AND COLDER
CONDITIONS FOR WED-THU NIGHT. UPPER FLOW THEN BECOMES MORE ZONAL FOR
WEEKEND LEADING TO MODERATING TEMPS...BUT SOME MODEL DIFFERENCES ON
HOW FAR SOUTH A EAST-WEST ORIENTED FRONT WILL PUSH SAT-MON. LEANED
TO HPC SOLUTION WITH FRONT REMAINING JUST N OF AREA...BUT CONFIDENCE
IS LOW. KEPT POPS TO JUST SLIGHT CHC FOR SAT NIGHT AND SUN WITH CHC
ON MONDAY.
UPR TROFFING WILL LEAD TO BELOW NORMAL TEMPS INTO FRIDAY...WITH THU
THE COLDEST DAY WITH HIGHS ONLY NEAR 50 INLAND. TEMPS FCST TO
MODERATE BACK INTO 60S SAT AND CONTINUE NEAR OR SLIGHTLY ABOVE
NORMAL SUN-MON...BUT WILL BE DEPENDENT ON FRONTAL LOCATION. IF FRONT
PUSHES THROUGH AND STALLS S OF AREA...TEMPS COULD BE 5-10 DEGS
COOLER.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY AFTERNOON /...
AS OF 130 PM MON...VFR CONDITIONS WILL CONTINUE THROUGH MUCH OF
THE EVENING AS A FRONT APPROACHES THE REGION TONIGHT. THE FRONT
WILL SLOWLY CROSS THE AREA TOMORROW AFTERNOON WITH RAIN AHEAD OF
ACTUAL BOUNDARY. AS MOIST SOUTHERLY FLOW INCREASES
TONIGHT...ANTICIPATE SOME SHOWERS TO MOVE INLAND FROM OFF THE
WATER AHEAD OF THE MAIN LINE OF PRECIPITATION. CEILINGS WILL BEGIN
TO SLOWLY LOWER TONIGHT AND WILL EVENTUALLY BECOME MVFR BY EARLY
TOMORROW MORNING. THE HEAVIER PRECIPITATION SHOULD CROSS THE TAF
SITES BETWEEN 12Z-18Z. THEREFORE...ANTICIPATE CEILINGS TO DROP TO
IFR CRITERIA...ALBEIT BRIEFLY. RAIN SHOULD TAPPER OFF BY TOMORROW
LATE AFTERNOON. EXPECT ANY THUNDERSTORM ACTIVITY WILL OCCUR
CLOSER TO THE COAST WITH BETTER INSTABILITY. CEILINGS WILL SCATTER
OUT TOMORROW EVENING AS DRIER AIR ADVECTS ACROSS THE AREA.
LONG TERM /TUE NIGHT THROUGH SATURDAY/...
AS OF 300 PM MONDAY...VFR EXPECTED TO RETURN TUE NIGHT IN WAKE OF
COLD FRONT MOVING OFF COAST...THEN PREVAILING THROUGH SAT WITH DRY
HIGH PRES GRADUALLY BUILDING OVER AREA FROM NW.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 335 PM MONDAY...WINDS ARE PRETTY UNIFORM ON THE COASTAL
WATERS AND SOUNDS THIS AFTERNOON WITH ESE/SE WINDS OF 10 TO 15
KNOTS. SEAS CONTINUE ROUGH...ESPECIALLY OVER THE NORTHERN WATERS
WITH 7 TO 10 FEET WITH CONTINUED LONG PERIOD SWELLS. SEAS HAVE
SUBSIDED SOMEWHAT ON THE SOUTHERN WATERS...BUT SHOULD INCREASE
FROM THE SE/S TONIGHT AS GRADIENT IS PINCHED AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. GUSTY SOUTH WINDS OF 20 TO 25
KNOTS WITH A FEW GUSTS TO 30 KNOTS ARE EXPECTED ON TUESDAY IN
ADVANCE OF THE FRONT WHICH SHOULD MOVE OFFSHORE DURING THE EARLY
EVENING HOURS. NO CHANGES MADE TO CURRENT HEADLINES.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM MONDAY...WIND SHIFT TO NW WILL FOLLOW FRONTAL PASSAGE
TUE EVENING WITH INITIAL CAA SURGE GENERALLY LESS THAN 20 KT EARLY
WED. STRONGER SURGE WITH GUSTS TO AROUND 25 KT WILL DEVELOP WED
EVENING WITH PASSAGE OF MAIN UPR TROF AND CONTINUE INTO THU NIGHT.
FLOW WILL THEN DIMINISH AND BACK TO W FRI AND FRI NIGHT AS HIGH PRES
MOVES ACROSS TO S.
LONG PERIOD SWELL FROM E-NE WILL GRADUALLY SUBSIDE DURING
PERIOD...BUT MODERATE TO STRONG NW WINDS WITH CAA SURGE WILL PRODUCE
SEAS TO AROUND 6 FT OVER OUTER PORTIONS INTO THU. SEAS FINALLY
EXPECTED TO SUBSIDE BELOW 6 FT FRIDAY...BUT MAY BUILD TO 6 FT SRN
PORTIONS LATE SAT WITH INCREASING SW WINDS.
&&
.TIDES/COASTAL FLOODING...
AS OF 340 PM MONDAY...HAVE EXTENDED THE HIGH SURF ADVISORY UNTIL 1
AM TONIGHT GIVEN CONTINUES LARGE SWELLS AND REPORTS OF ROADWAY
ISSUES ALONG HIGHWAY 12 OVER THE OUTER BANKS.
LARGE HIGH-ENERGY WAVES FROM A DEEP LOW PRESSURE SYSTEM OVER THE
NORTHWESTERN ATLANTIC WILL CONTINUE TO BRING HIGH SURF CONDITIONS
AND PERIODS OF OCEAN OVERWASH ACROSS THE OBX NORTH OF CAPE
HATTERAS THROUGH THIS EVENING. SEAS ARE SLOWLY COMING DOWN BUT
WILL STILL LIKELY HAVE BREAKERS OF 8 FT OR GREATER THIS EVENING.
HIGHWAY 12 HAS BEEN IMPACTED BY SIGNIFICANT OVERWASH ESPECIALLY
AT HIGH TIDE AND PORTIONS HAVE BEEN CLOSED AT TIMES NEAR MIRLO AND
SHOULD CONTINUE INTO THIS EVENING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...HIGH SURF ADVISORY UNTIL 1 AM EDT TUESDAY FOR NCZ103.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT FRIDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL NOON EDT THURSDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...JBM
AVIATION...LEP/JBM/CTC
MARINE...JBM/CTC
TIDES/COASTAL FLOODING...CTC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
203 AM EDT SUN MAR 10 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL DRIFT EASTWARD IN ADVANCE OF
A COLD FRONT THAT WILL CROSS CENTRAL NC EARLY TUE.
&&
.NEAR TERM /TONIGHT/...
AS OF 915 PM SUNDAY...
REST OF TONIGHT: BIGGEST CHALLENGE TONIGHT IS HOW MUCH STRATUS WILL
FORM -- IF ANY -- AND WHERE IT WILL BE MOST WIDESPREAD. HIGH
PRESSURE CENTERED JUST OFF THE MAINE COAST AND EXTENDING DOWN THE
EASTERN SEABOARD ACCORDING TO THE LATEST SURFACE ANALYSIS WILL SLIP
SLOWLY EASTWARD OFF THE COAST TONIGHT... RESULTING IN A SLOW BUT
STEADY INFLUX OF ATLANTIC-SOURCE NEAR-SURFACE MOISTURE INTO NC AS
WINDS SWING AROUND TO SOUTHEASTERLY. SURFACE DEW POINTS ACROSS
CENTRAL NC HAVE VARIED WIDELY FOR THE LAST SEVERAL HOURS... FROM
15-20 EAST/CENTRAL TO 25-34 WEST LATE THIS AFTERNOON... AND THIS
WIDE RANGE REMAINS ALBEIT WITH A MARKED INCREASE INTO THE 20S AND
LOW 30S IN THE COASTAL PLAIN... PUSHING THE VALUES IN THE TEENS UP
INTO THE NORTHEAST PIEDMONT. DEW POINTS IN THE UPPER 30S AND 40S ARE
NOT FAR AWAY... RIGHT AT THE COAST AND JUST OFFSHORE... AND I SEE
NOTHING TO SUGGEST THAT THIS HIGHER LOW-LEVEL MOISTURE WILL NOT
CONTINUE TO SURGE INTO THE COASTAL PLAIN OVERNIGHT. THE LATEST RUNS
OF THE RAP SUPPORT THIS ONSHORE SURGE OF MOISTURE... AS DO RECENT
HRRR RUNS WHICH DEPICT RAPID DEVELOPMENT OF LOW CIGS ALONG AND EAST
OF I-95 BEFORE 09Z. WORKING AGAINST SUCH A SCENARIO IS THE RESIDENT
DRY AIR NOTED ON AREA SOUNDINGS... AS LOW LEVELS ARE MORE MOIST AT
MHX/CHS THAN AT GSO BUT NOT INCREDIBLY SO. BUT GIVEN THE STABLE
NEAR-SURFACE LAYER... THE AFTERNOON ABUNDANCE OF STRATOCU JUST OFF
THE CAROLINA COAST... AND WITH A MULTITUDE OF MODELS (INCLUDING BUFR
SOUNDINGS FROM THE NAM AND GFS) SHOWING LOW STRATUS FORMING BY
MORNING ESPECIALLY IN THE EAST... WILL INCREASE SKY COVER ESPECIALLY
IN THE EASTERN HALF OF THE CWA. MOISTURE REMAINS ELEVATED IN THE
WESTERN PIEDMONT AS WELL... AND UPSLOPE FLOW MAY RESULT IN AREAS OF
STRATUS HERE AS WELL... ALTHOUGH TRAJECTORIES SUGGEST THAT THE
ISOLATED POCKET OF DRY SURFACE AIR NOW FOUND OVER INTERIOR SOUTHEAST
NC AND NORTHEAST SC WILL TRANSLATE INTO THIS AREA... LIMITING
STRATUS FORMATION SOMEWHAT. TEMPS HAVE ALREADY DROPPED INTO THE 40S
IN ISOLATED SPOTS BUT 50S REMAIN WIDESPREAD ENOUGH TO JUSTIFY A
SLIGHT UPWARD TICK IN LOWS TONIGHT... GIVEN THE ANTICIPATED CLOUD
DEVELOPMENT. LOWS 39-46. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 225 PM SUNDAY...
LEADING EDGE OF A 45-50KT SOUTHERLY LOW-LEVEL JET EMBEDDED IN THE
BROAD WARM AIR CONVEYOR BELT DOWNSTREAM OF THE SYSTEM WILL BEGIN TO
ADVECT GULF MOISTURE NORTHWARD LATE MONDAY AFTERNOON...WHICH WILL
RESULT IN SCATTERED SHOWERS BREAKING OUT OVER THE AREA LATE MONDAY
AFTERNOON/EARLY EVENING. DEEP LAYER FORCING VIA DIFFLUENT FLOW
ALOFT ASSOCIATED WITH A COUPLED JET STRUCTURE ATOP STRONG LOW-LEVEL
MOISTURE FLUX CONVERGENCE ALONG THE SOUTHERLY LOW-LEVEL JET
WILL ARRIVE FROM THE WEST AOA MIDNIGHT MONDAY NIGHT WITH
SIGNIFICANT-WIDESPREAD(CATEGORICAL)CONVECTIVE SHOWERS SPREADING WEST
TO EAST THROUGH THE AREA THROUGH 15Z TUESDAY MORNING BEFORE THIS
SUPPORT MOVES OFFSHORE. THE LOW-LEVEL JET AND ATTENDANT LINE OF
CONVECTION WILL SERVE AS THE EFFECTIVE FRONT WITH ONLY AN ISOLATED
SHOWER EXPECTED WITH THE ACTUAL TRAILING SFC COLD FRONT AS IT MOVES
THROUGH THE AREA BETWEEN 15 TO 21Z TUESDAY. A SOLID ONE QUARTER TO
ONE HALF INCH OF RAINFALL LOOKS TO BE IN ORDER FOR ALL OF CENTRAL
NC.
THUNDER/SEVERE THREAT:
WITH THE STRONG TROUGH DYNAMICS AND LOW-LEVEL KINEMATIC
FIELDS TRAVERSING THE CAROLINAS BETWEEN 06 TO 15Z TUESDAY...
WEAK TO MODEST MID-LEVEL LAPSE RATES OF 5.5 TO 6.0 C/KM--NOCTURNAL
BOUNDARY LAYER COOLING OVERNIGHT ALONG WITH RATHER WIDESPREAD
LOW-LEVEL CLOUD COVER ACROSS THE AREA THROUGH MIDDAY TUESDAY
WILL RESULT IN MEASLY INSTABILITY (100-200 J/KG MUCAPE)ACROSS
EASTERN NC. SO WHILE NOT ZERO...BOTH THUNDER AND A SEVERE THREAT ARE
VERY LOW. WILL NOT INCLUDE A MENTION OF THUNDER AT THIS TIME.
TEMPERATURES:
MILD OVERNIGHT LOWS MONDAY NIGHT GIVEN WIDESPREAD RAIN AND CLOUDS.
LOWS IN THE LOWER 50S NW TO MID-UPPER 50S SOUTHEAST. NOT MUCH
DIFFERENCE IN HIGHS TEMPERATURES FROM MONDAY TO TUESDAY WITH CAA
DELAYED UNTIL TUESDAY NIGHT. AS SUCH...CLOUD COVER WILL BE THE MAIN
DETERMINING FACTOR. HIGHS BOTH DAYS IN THE LOWER 60S NW TO NEAR 70
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 225 PM SUNDAY...
TO START THE LONG TERM PERIOD...THE COLD FRONT AND ASSOCIATED PRECIP
ARE EXPECTED TO BE EAST OF THE AREA BY EARLY TUESDAY EVENING...WITH
ANY LINGERING CLOUDS ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA CLEARING SHORTLY AFTER. COLD AIR ADVECTION BEHIND THE DEPARTING
FRONT WILL LEAD TO COOLER OVERNIGHT LOWS...GENERALLY IN THE MID TO
UPPER 30S. THEN...MUCH OF THE PERIOD IS EXPECTED TO BE DOMINATED BY
A BROAD UPPER TROUGH. THIS WILL RESULT IN BELOW NORMAL TEMPS...
ESPECIALLY WED AND THU AS SOME COLD AIR ADVECTION CONTINUES. TEMPS
SHOULD REBOUND SLIGHTLY TO NEAR NORMAL BY THE END OF THE WEEK AND
INTO THE WEEKEND AS HEIGHTS RISE SOME. WITH REGARDS TO ANY PRECIP...
WITH NORTHWESTERLY FLOW ALOFT PERSISTING ACROSS OUR REGION...MODELS
CONTINUE TO PROG SEVERAL DISTURBANCES/CLIPPERS MOVING SOUTHEAST
WITHIN THIS FLOW. HOWEVER...UNCERTAINTY REMAINS HIGH WITH RESPECT TO
EXACT TRACK OF THESE (AND TIMING IN GENERAL) AND WITH MOISTURE
REMAINING RATHER LIMITED...WILL MAINTAIN A DRY FORECAST THROUGH AT
LEAST THE END OF THE WEEK. UNCERTAINTY INCREASES EVEN MORE BY THE
WEEKEND AS MODELS ARE SHOWING A BACKDOOR FRONT IMPACTING THE AREA
(TO VARYING DEGREES). MOISTURE IS PROGGED TO BEGIN TO INCREASE
DURING THIS TIME FRAME AS WELL AND THEREFORE WILL GO AHEAD AND
INTRODUCE SLIGHT CHANCE POPS FOR THE WEEKEND...ALTHOUGH CONFIDENCE
IS FAIRLY LOW.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 201 AM MONDAY...
24-HR TAF PERIOD:
HIGH CLOUDS INCREASING AHEAD OF THE COLD FRONT APPROACHING THE
AREA... INDICATIONS ARE THAT INCREASING SOUTHERLY FLOW AND MOISTURE
WILL RESULT IN THE FORMATION OF LOW STRATUS IN THE EARLY MORNING
OVER THE AREA... AND DEWPOINTS ACROSS THE COASTAL PLAIN AND PIEDMONT
HAVE RISEN OVER THE PAST FEW HOURS TO THE MID AND UPPER 20S. CLOUDY
CONDITIONS WILL CONTINUE THROUGH THE DAY...WITH CIGS RISING IN THE
MORNING HOURS TO MVFR AFTER 12Z. RAIN CHANCES WILL INCREASE LATE IN
THE 24 HOUR PERIOD... AFFECTING INT AND GSO FIRST BEFORE MOVING EAST.
LOOKING AHEAD:
RAIN WILL BE EXITING THE REGION AFTER 18Z TUESDAY... BRINGING A
RETURN TO VFR CONDITIONS. WINDS GUSTING 15 TO 20KTS WILL BE POSSIBLE
DURING THE AFTERNOON HOURS ON TUESDAY AND WEDNESDAY. VFR CONDITIONS
REMAIN LIKELY THROUGH THE REST OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...HARTFIELD
SHORT TERM..CBL
LONG TERM...KRR
AVIATION...SEC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
328 PM CDT MON MAR 11 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...
MAIN HIGHLIGHT IN THE SHORT TERM IS A WINTER WEATHER ADVISORY
ACROSS THE NORTH...AND THE JAMES RIVER VALLEY MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING.
THE LATEST SURFACE MAP SHOWS A STRONG COLD FRONT STRETCHING FROM
NEAR LAKE WINNIPEG SOUTHWEST INTO REGINA. A RATHER LARGE AREA OF
3HR MAX PRESSURE RISES OF 4MB WAS CENTERED OVER SOUTH CENTRAL
SASKATCHEWAN. NORTHWEST WINDS OF 25 TO 35 MPH ASSOCIATED WITH THIS
WERE OCCURRING OVER SEVERAL LOCATIONS...WITH VISIBILITIES RANGING
ANYWHERE FROM 3/4 OF A MILE TO 8 MILES. WITH RECENT SNOWFALL IN
THE NORTH AND THE JAMES RIVER VALLEY...IN COMBINATION WITH THE
GUSTY WINDS TO 35 MPH TONIGHT...SIGNIFICANT BLOWING AND DRIFTING
SNOW WILL CAUSE VISIBILITIES OF A MILE OR LESS AND HAZARDOUS
TRAVEL. THE LATEST RAP MODEL DRAGS THE CENTER OF THE PRESSURE RISE
AREA INTO NORTHERN NORTH DAKOTA BY 06Z AND INTO THE JAMES RIVER
VALLEY AT 12Z. SCATTERED SNOW SHOWERS WILL ACCOMPANY THE COLD
FRONT WITH ACCUMULATIONS OF AROUND ONE INCH. THIS WILL FURTHER ADD
TO THE REDUCTION IN VISIBILITIES AND HAZARDOUS TRAVEL OVERNIGHT
AND EARLY TUESDAY MORNING. DESPITE LARGE SCALE ASCENT ABSENT FROM
THIS SYSTEM...MOST OF THE SNOW SHOWERS WILL BE DRIVEN BY LOW LEVEL
INSTABILITY. DECENT LOW LEVEL LAPSE RATES ARE ACHIEVED AS THE COLD
H85 POCKET OF -12C TO -14C SLIDES INTO WESTERN AND CENTRAL NORTH
DAKOTA TONIGHT. AS MENTIONED ABOVE...SNOWFALL ACCUMULATIONS OF
AROUND ONE INCH POSSIBLE WITH THESE SNOW SHOWERS.
FOR TUESDAY...SCATTERED SNOW SHOWERS AND GUSTY WINDS LINGER IN THE
JAMES RIVER VALLEY DURING THE MORNING. OTHERWISE A COLDER DAY WITH
A 1032MB SURFACE HIGH PRESSURE ARRIVING IN NORTHWEST NORTH DAKOTA
BY 18Z WITH LIGHTER WINDS AND MORE SUNSHINE DEVELOPING FROM WEST
TO EAST. HIGHS TUESDAY WILL RANGE FROM 20 NORTH TO LOWER 30S
SOUTHWEST.
FOR TUESDAY NIGHT..WARM AIR ADVECTION ARRIVES IN THE WEST WITH
UPGLIDE/ASCENT ADVERTISED ON THE 285-295K PRESSURE SURFACES. THUS
HAVE SLIGHT CHANCE OF SNOW TUESDAY EVENING IN THE WEST FOLLOWED BY
A CHANCE AFTER MIDNIGHT. SNOWFALL AMOUNTS OF AROUND ONE HALF INCH
POSSIBLE TUESDAY NIGHT IN THE WEST.
.LONG TERM...WEDNESDAY THROUGH MONDAY NIGHT...
HIGHLIGHTS OF THE EXTENDED FORECAST ARE ABOVE AVERAGE TEMPERATURES
TO BEGIN THE PERIOD...WITH TEMPERATURES TRENDING POTENTIALLY BELOW
NORMAL LATE NEXT WEEK AND INTO THE WEEKEND. WIDESPREAD ACCUMULATING
SNOW IS ALSO POSSIBLE THURSDAY NIGHT INTO FRIDAY.
A WARM FRONT IS FORECAST TO PROPAGATE ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE DAY ON WEDNESDAY. A RATHER LARGE
TEMPERATURE GRADIENT IS EXPECTED WITH HIGHS IN THE 20S AND LOWER 30S
OVER THE SNOWPACK AHEAD OF THE WARM FRONT...TO THE UPPER 50S ACROSS
THE SOUTHWEST WITH BARE GROUND. THE 12 UTC GFS BECOMES A CLEAR
OUTLIER FRIDAY ONWARDS AS IT IS THE DEEPEST AND FASTEST SOLUTION IN
REGARDS TO A SURFACE LOW ACROSS NORTHERN MONTANA THURSDAY
NIGHT...PROPAGATING INTO MINNESOTA ON FRIDAY. THUS...FOLLOWED THE 12
UTC ECMWF/GEM WHICH BUILD ARCTIC HIGH PRESSURE INTO NORTH DAKOTA
FRIDAY THROUGH THE WEEKEND. THESE MODELS ALSO HAVE SHOWN GOOD
TEMPERATURE VERIFICATION WITH BIAS CORRECTION APPLIED TO ACCOUNT
FOR THE FAIRLY CONSISTENT SNOW/SNOW FREE AREAS. THUS...ANOTHER LARGE
TEMPERATURE GRADIENT IS POSSIBLE THURSDAY WITH HIGHS IN THE 20S
NORTH TO THE LOWER 60S SOUTHWEST...WITH HIGHS 10 TO 20 DEGREES
COOLER FOR SATURDAY AS THE ARCTIC HIGH BUILDS IN. IN REGARDS TO
PRECIPITATION...WIDESPREAD ACCUMULATING SNOW IS POSSIBLE THURSDAY
NIGHT INTO FRIDAY WITH FRONTOGENESIS ASSOCIATED WITH THE BAROCLINIC
ZONE ON THE LEADING EDGE OF THE AFOREMENTIONED SURFACE HIGH.
&&
.AVIATION...AS OF 2030 UTC...A WEAK FRONT WAS ENTERING EASTERN NORTH DAKOTA.
STRONG NORTHWEST WINDS WITH GUSTS OF 25-30 KTS WERE OCCURRING BEHIND
THIS FRONT IN WESTERN AND CENTRAL NORTH DAKOTA. A SECOND...AND STRONGER
COLD FRONT LOCATED ACROSS SOUTHEAST SASKATCHEWAN WILL DROP SOUTH INTO
NORTH DAKOTA LATE THIS AFTERNOON AND THROUGH THE EVENING. EVEN STRONGER
GUSTS OF 30-40 KTS ARE EXPECTED BEHIND THIS FRONT WITH SCATTERED SNOW
SHOWERS. BLOWING SNOW IS ALSO A CONCERN AT KISN...KMOT AND KJMS THIS
EVENING AND TONIGHT...WITH IFR VISIBILITIES WHEN COMBINED WITH SNOW
SHOWERS POSSIBLE. OTHERWISE...MVFR CEILINGS ARE EXPECTED BEHIND THE
SECOND FRONT AS STRATUS OVERSPREADS THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM CDT TUESDAY FOR
NDZ021>023-025-036-037-047-048-050-051.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR NDZ001>005-009>013.
&&
$$
SHORT TERM...KS
LONG TERM/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
656 AM EDT MON MAR 11 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW AHEAD OF A COLD FRONT WILL BRING WIDESPREAD
SHOWERS TO THE REGION TODAY. THE COLD FRONT WILL PUSH EAST TONIGHT
WHICH WILL SIGNAL THE END OF WIDESPREAD PRECIPITATION. A COLD
UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE GREAT LAKES AND
OHIO VALLEY TUESDAY INTO WEDNESDAY. THIS PATTERN WILL BRING A
THREAT OF RAIN AND SNOW SHOWERS ALONG WITH BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NWP MODELS WERE IN FAIRLY DECENT AGREEMENT IN TERMS OF SYNOPTIC
SCALE FORCING AND TIMING OF FEATURES. HAVE USED A BLEND OF THE
NAM...GFS AND THE RAP FOR THE NEAR TERM FORECAST.
PRECIPITATION ACROSS THE REGION TODAY WILL COME IN TWO SEPARATE
WAVES. THE FIRST BOUT OF SHOWERS WILL ACCOMPANY A MOIST...LOW
LEVEL JET WHICH WILL PUSH SOUTHWEST TO NORTHEAST THROUGH THE
MORNING AND EARLY AFTERNOON HOURS. AS THIS SHIFTS EAST...AN UPR
LVL S/WV AND ACCOMPANYING SFC COLD FRONT WILL SWING THROUGH THE
WESTERN ZONES THIS AFTERNOON...PUSHING THROUGH THE EASTERN ZONES
BY EARLY EVENING. THIS FEATURE WILL ALSO BRING ANOTHER ROUND OF
SHOWERS. RAINFALL WITH THE FIRST WAVE IS EXPECTED TO BE THE
HEAVIEST WITH 0,50 TO 1.25 INCHES OF RAIN EXPECTED. THERE CONTINUES
TO BE SOME CONCERN FOR FLOODING GIVEN THE RECENT SNOW MELT AND
MOIST TO NEARLY SATURATED GROUND...PARTICULARLY IN THE
WHITEWATER...MIAMI...AND UPPER SCIOTO RIVER BASINS. ATTM...BELIEVE
WIDESPREAD FLOODING IS NOT EXPECTED GIVEN STEADY BUT PROGRESSIVE
MOVEMENT TO THE EAST OF THE FIRST BATCH OF SHOWERS. HOWEVER...WILL
CONTINUE TO MONITOR FOR ANY POTENTIAL FLOOD ADVISORIES GIVEN HIGH
STREAM LEVELS PER USGS WEB SITE AND SATURATED SOILS. WILL ALSO
HIGHLIGHT THIS THREAT IN THE HWO PRODUCT. WILL ALSO MONITOR THE
LINE OF SHOWERS EXPECTED WITH FRONTAL PASSAGE AS SOME MODELS
INDICATE THAT SOME GUSTY WINDS MAY OCCUR. AS FOR TEMPERATURES...THEY
WILL BE TRICKY GIVEN PERSISTENT RAIN ACRS THE WEST BUT LATE
ARRIVING IN THE FAR EAST. HAVE HIGHS RANGING FROM THE LOWER 50S
WEST TO THE UPPER 50S FAR EAST. HOWEVER...IF RAIN IS SLOWER TO
ARRIVE IN THE FAR EAST...TEMPERATURES MAY WARM INTO THE 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
AFOREMENTIONED COLD FRONT AND S/WV WILL MOVE OFF TO THE EAST THIS
EVENING WHICH WILL SIGNAL THE END OF WIDESPREAD PCPN. TEMPERATURES
WILL FALL OVERNIGHT IN THE CAA PATTERN BEHIND THE FRONT. MODELS
CONTINUE TO SUGGEST THAT AN EMBEDDED DISTURBANCE WILL APPROACH THE
AREA FROM THE WEST LATE. THIS MAY TRIGGER A FEW SNOW SHOWERS ACRS
THE NRN ZONES BY MORNING.
FOR THE PERIOD TUESDAY INTO WEDNESDAY...A COLD UPR LEVEL TROUGH IS
FORECAST TO DIG SOUTHEAST INTO THE GREAT LAKES AND OHIO VALLEY.
SKIES ON TUESDAY WILL BE MOSTLY CLOUDY WITH PERHAPS A FEW LIGHT
RAIN AND SNOW SHOWERS ACROSS THE NORTH IN THE CAA PATTERN WHICH
WILL BRING SOME LOW LEVEL INSTABILITY. AN EMBEDDED S/WV ROTATING
AROUND THE LOW IS EXPECTED TO PASS ACRS THE REGION TUESDAY NIGHT.
THIS FEATURE WILL BRING A CHANCE OF SNOW SHOWERS AND HAVE RAISED
POPS UP INTO THE 40 PERCENT RANGE. ON WEDNESDAY...CAA WILL BE IN
FULL SWING AS LOW LEVEL MOIST...COLD CYCLONIC FLOW ACROSS THE
GREAT LAKES COMBINED WITH SOME DAYTIME HEATING WILL RESULT IN A
CHANCE OF SNOW SHOWERS...BEST FAVORED FROM LATE MORNING INTO THE
MID AFTERNOON HOURS. MODEL SOUNDINGS DEPICT STEEP LOW LEVEL LAPSE
RATES ALONG WITH THE LOW LEVEL MOISTURE INTERSECTING THE DENDRITIC
GROWTH ZONE. THE MAJORITY OF OPERATIONAL MODELS USED THIS FAR OUT
OUR NOT CONVECTIVE ALLOWING...AND AS A RESULT...MAY BE UNDER DOING
THE CONVECTIVE ACTIVITY AS HAS BEEN THE CASE THIS PAST WINTER.
HAVE RAISED POPS TO 40 PERCENT...BUT WOULD NOT BE SURPRISED IF THE
ACTIVITY ENDS UP BEING IN THE LIKELY CATEGORY.
COLD UPR LEVEL TROUGH WILL MOVE EAST WEDNESDAY NIGHT. THIS SHOULD
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE REGION LATE. CLOUDS
WILL DECREASE AND WITH THE LOSS OF DAYTIME HEATING...SNOW SHOWERS
SHOULD WANE FROM WEST TO EAST.
AS FOR TEMPERATES...HIGHS ON TUESDAY WILL RANGE FROM THE UPPER
30S NORTH TO THE MID 40S SOUTH. HIGHS ON WEDNESDAY WILL STRUGGLE
TO WARM INTO THE MID AND UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL PUSH ACROSS THE AREA THURSDAY INTO
FRIDAY. THIS WILL PROVIDE FOR MAINLY DRY CONDITIONS ALONG WITH A
GRADUAL WARM UP EACH DAY. IN A NORTHWEST FLOW PATTERN
ALOFT...SHORT WAVE ENERGY WILL DROP DOWN INTO THE AREA FRIDAY INTO
SATURDAY. HOWEVER...THERE ARE SOME TIMING/STRENGTH AND PLACEMENT
ISSUES BETWEEN THE 12Z GFS/CMC AND 00Z ECMWF WITH THE GFS THE
FASTEST AND THE ECMWF THE SLOWEST. THE OVERALL TREND HAS BEEN
SLOWER SO WILL TRIM BACK POPS HEADING INTO FRIDAY AFTERNOON AND
THEN INCREASE THEM FOR FRIDAY NIGHT INTO SATURDAY. BOTH THE GFS
AND ECMWF LOOK LIKE THEY ARE TRYING TO LAY OUT A BOUNDARY
SOMEWHERE ACROSS THE OHIO OR TENNESSEE VALLEY LATE IN THE WEEKEND.
THIS WILL LIKELY LINGER PCPN ON INTO SUNDAY...ESPECIALLY ACROSS
OUR SOUTHERN AREAS. PTYPE THROUGH THE LATER PART OF THE LONG TERM
SHOULD GENERALLY BE RAIN...ALTHOUGH LOW LEVELS COULD COOL OFF
ENOUGH TO SEE THE POSSIBILITY OF SOME SNOW MIXING IN ACROSS THE
NORTH. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL
THROUGH THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A COLD FRONT IS SLOWLY APPROACHING THE REGION...AND A STEADY
STREAM OF RAIN WILL CONTINUE TO MOVE NORTHEAST THROUGH THE REGION
TODAY. WHILE CLOUDS OVER THE AREA ARE STILL GENERALLY IN THE
4000-6000 FOOT RANGE...SIGNIFICANTLY LOWER CLOUDS ARE LOCATED
UPSTREAM IN PARTS OF INDIANA AND KENTUCKY. TEMPO GROUPS HAVE BEEN
INCLUDED FOR ALL THE TAF SITES TO ATTEMPT TO TIME OUT THESE LOWER
CEILINGS...WHICH ARE EXPECTED TO BE IN THE 1000-1500 FOOT RANGE.
IFR CEILINGS ARE NOT OUT OF THE QUESTION...BUT IT LOOKS LIKE THIS
WILL BE MORE LIKELY NORTH AND WEST OF THE TAF SITES.
AS THE RAIN CONTINUES...OCCASIONAL MVFR VISIBILITIES ARE EXPECTED.
BY AFTERNOON...THE FRONTAL PASSAGE WILL PROMPT A QUICK CHANGE IN
WIND DIRECTION FROM THE SOUTH TO THE WEST-SOUTHWEST. WIND GUSTS
AHEAD OF...DURING...AND JUST AFTER THE FRONTAL PASSAGE MAY REACH
AS HIGH AS THE 25-30 KNOT RANGE. THE VAST MAJORITY OF THE
PRECIPITATION IS AHEAD OF THE FRONT...BUT SOME LIGHT SHOWERS ARE
EXPECTED BEHIND IT.
THOUGH THERE MAY BE SOME BRIEF CLEARING IN THE CLOUD DECKS
(ESPECIALLY JUST AFTER THE FRONT PASSES)...MVFR CEILINGS ARE
EXPECTED TO BE THE PREVAILING CONDITION. THESE CLOUDS SHOULD
PERSIST (AND EVEN LOWER A BIT) GOING INTO THE OVERNIGHT PERIOD AND
EARLY TUESDAY MORNING.
OUTLOOK...MVFR CEILINGS WILL BE POSSIBLE THROUGH TUESDAY MORNING.
MVFR CEILINGS ARE AGAIN EXPECTED ON TUESDAY NIGHT INTO WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1054 PM CDT TUE MAR 12 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 342 PM CDT TUE MAR 12 2013
TEMPERATURES AND TRENDS TONIGHT WILL BE VERY DEPENDENT ON A
DIFFICULT CLOUD FORECAST. A LARGE PART OF CURRENT CLOUD COVERAGE IS
DIURNALLY SUPPORTED AS BREAKS HAVE FILLED BACK IN DURING THE
DAY...WITH SCATTERED COVERAGE OF VERY LIGHT SNOW OR FLURRIES OVER
MUCH OF THE CWA. RAP SOMEWHAT A JECKYLL AND HYDE OF LATE WHEN IT
COMES TO LOWER CLOUD PREDICTION...BUT GENERALLY SEEMS ON TRACK WITH
CURRENT CLOUDS. HAS A MUCH SLOWER CLEARING RATE FROM WEST TO
EAST...BUT PROBABLY TOO MUCH SO WITH THE DEGREE OF DIURNALLY DRIVEN
CLOUDS WHICH WILL ERODE QUICKLY WEST...AND TO SOME DEGREE IN THE FAR
EAST AS WELL...LEAVING A MORE PERSISTENT BAND DOWN THE MIDDLE TO
DISSIPATE MORE SLOWLY AND BUILD EAST. COMPLICATING TRENDS WILL BE
THE SLOW EASTWARD SHIFT IN SURFACE RIDGE...BRINGING LIGHT RETURN
FLOW TO AREAS FROM THE JAMES VALLEY WEST LATER NIGHT...ALONG WITH
INCREASING HIGH LEVEL CLOUDS.
COULD BE A FEW LOCATIONS OF BLOWING SNOW THROUGH LATE AFTERNOON IN
DEEPER SNOW AREAS NORTH AND EAST...BUT OVERALL TREND IN WINDS GOING
INTO THE EVENING WILL BE DOWN...AND EXPECT WILL NOT CONTINUE INTO
THE EVENING. MUCH OF CURRENT PRECIPITATION RESULT OF THE STEEP LOW
LEVEL LAPSE RATES...AND WILL PROBABLY TAKE A COUPLE OF HOURS INTO
THE EVENING BEFORE FULLY LOSING A FLURRY THREAT WITH TEMPS IN CLOUD
LAYER SUPPORTIVE OF ICE PROCESS.
ON WEDNESDAY...DECENT COVERAGE OF MID/HIGH CLOUDS WILL PUSH EASTWARD
ACROSS THE AREA. WEAKER LOW LEVEL GRADIENT AND SNOWCOVER EAST WILL
RESTRAIN TEMPERATURES TO THE LOWER PORTIONS OF GUIDANCE RANGE WITH
UPPER 20S. MUCH WARMER AIRMASS PUSHES INTO THE WEST...SHOULD ALLOW
SOME LOWER 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 342 PM CDT TUE MAR 12 2013
BOTH THURSDAY AND FRIDAY PLACE THE CWA RIGHT ALONG A STRONG THERMAL
GRADIENT IN THE LOW LEVELS WHICH MAKES FORECASTING HIGHS TRICKY. NOT
JUST SIMPLY DUE TO THE STRONG THERMAL GRADIENT BUT IF THURSDAY DOES
NOT PROVIDE ENOUGH SOLAR RADIATION THE SNOW MAY NOT MELT AS MUCH AS
EXPECTED WHICH COULD INFLUENCE HIGHS ON THURSDAY. WILL PLAN ON SOME
MELTING TO OCCUR WEDNESDAY IN CENTRAL SOUTH DAKOTA WHICH WILL ALLOW
TEMPERATURES TO CLIMB A BIT SOUTH OF INTERSTATE 90 WHERE MUCH OF
THAT AREA IS ALREADY SNOW FREE...ON THE SOUTH DAKOTA SIDE OF THINGS.
SO WILL GO CLOSE TO 60 IN THESE LOCATIONS TAPERING OFF TO NEAR 40 IN
SOUTHWEST MINNESOTA. BUT AGAIN...WITH THE TIGHT THERMAL GRADIENT
CONFIDENCE IS NOT EXTREMELY HIGH. THIS THERMAL GRADIENT SHIFTS A BIT
NORTHWARD ON THURSDAY NIGHT INTO FRIDAY BEFORE SLIDING BACK
SOUTHWARD AS A WAVE MOVES THROUGH NORTH DAKOTA WHICH WILL PUSH THIS
COLDER AIR SOUTH. WILL KEEP TEMPERATURES MILD THURSDAY NIGHT...WITH
LOWS IN UPPER 20S TO LOWER 30S. WILL RULE OUT THE GFS AND LEAN
TOWARDS THE EC AND NAM OUTPUT ON FRIDAY. THE GFS DOES NOT SEEM TO
HANDLE LOW LEVEL FEATURES OF SYSTEMS TO THE NORTH VERY WELL AS IT
TENDS TO COLLAPSE THE COLD AIR INTO THE PRE FRONTAL TROUGH WHILE THE
EC AND NAM TEND TO HANDLE THIS BETTER. WHAT THIS MEANS IS THAT
FRIDAY SHOULD BE VERY MILD ...ESPECIALLY DOWN THE MISSOURI RIVER
WHICH WILL AGAIN SEE TEMPERATURES CLIMB TO AROUND 60 WHILE 40 TO 45
SHOULD BE MORE COMMON IN THE NORTH. IN FACT IF THINGS ARE AS SLOW AS
THE NAM SUGGESTS IT COULD CLIMB INTO THE LOWER 50S ALONG THE HIGHWAY
14 CORRIDOR.
SATURDAY AND SUNDAY WILL SEE FAIRLY STRONG WEST/NORTHWEST FLOW ALOFT
AHEAD OF A MARGINALLY AGREED UPON FORECAST TROUGH OF LOW PRESSURE
FOR SUNDAY NIGHT INTO MONDAY NIGHT. WITH COLD AIR IN PLACE ON
SATURDAY MORNING WEAK EAST TO SOUTHEAST FLOW WILL TRY TO RETURN
CONDITIONS BACK TO NORMAL BUT COLDER AIR WILL BEGIN TO SINK SOUTH
SUNDAY AHEAD OF THE TROUGH OF LOW PRESSURE. OVERALL EACH OF THE
MODELS IS COLD ENOUGH THAT ANY PRECIPITATION THAT FALLS WOULD BE
SNOW WITH AN EAST TO SOUTHEAST LOW LEVEL FLOW ADVECTING IN THE
COOLER AND DRIER AIR TO THE EAST. COLDER AIR BURIES IN BEHIND THIS
WAVE TUESDAY INTO WEDNESDAY BUT AGAIN...SOME DECENT TIMING
DIFFERENCES SO CONFIDENCE IS AVERAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1050 PM CDT TUE MAR 12 2013
MOST OF THE CWA SHOULD REMAIN VFR THROUGH TONIGHT. SOME MVFR STRATUS IS
LINGERING ACROSS PORTIONS OF OUR EAST...BUT EXPECT MOST OF THIS TO
CONTINUE TO DISSIPATE OVER THE NEXT FEW HOURS. WINDS WILL ALSO
CONTINUE TO DIMINISH AND THEN TURN SOUTH SOUTHEASTERLY
TOMORROW...GENERALLY AT 12 KTS OR LESS. ONLY EXPECTING SOME
INCREASING MID AND HIGH CLOUDS TOMORROW...WITH VFR CONDITIONS
CONTINUING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
928 AM CDT MON MAR 11 2013
.SHORT TERM...
928 AM CDT MON MAR 11 2013
GIVEN CURRENT RADAR TREND WITH LINGERING STRETCHED DEFORMATION
BAND/STRONG 700-600MB FRONTOGENETIC FORCING...HAVE OPTED TO
EXTEND THE CURRENT WINTER STORM WARNING/WINTER WEATHER ADVISORY
TIL NOON TODAY. ALSO WITH TIGHTENING BAND OF SNOW...TRIMMED OFF
DODGE COUNTY IN MN FROM THE WINTER STORM WARNING AND MONROE COUNTY
IN WISCONSIN FROM THE WINTER WEATHER ADVISORY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
346 AM CDT MON MAR 11 2013
A FAIRLY ACTIVE NORTHWEST FLOW REMAINS ACROSS THE AREA THROUGH
THIS TIME PERIOD. SHORT WAVES WILL BRING CHANCES OF PRECIPITATION
ON THURSDAY...FRIDAY AND FRIDAY NIGHT...AND SUNDAY AND SUNDAY
NIGHT. THE PRECIPITATION TYPES DURING THIS TIME FRAME IS HIGHLY
DEPENDENT ON WHERE THE BAROCLINIC ZONE SETS UP. THEREFORE JUST
WENT WITH A MIX OF RAIN AND SNOW FOR THESE TIME PERIODS.
&&
.AVIATION...TODAY AND TONIGHT
627 AM CDT MON MAR 11 2013
AN ELONGATED AREA OF LOW PRESSURE WAS LOCATED FROM NORTHERN
ILLINOIS INTO EASTERN WISCONSIN. DEFORMATION BAND OF SNOW WAS
LOCATED OVER NORTHEAST IOWA INTO SOUTHEAST MINNESOTA...AFFECTING
THE KRST TAF SITE WITH 1 1/2SM VISIBILITY IN SNOW. 11.08Z HRRR SHOWS
THIS BAND TO TRANSLATE EASTWARD THIS MORNING AS THE LOW PULLS
AWAY. THUS EXPECT VISIBILITIES TO DROP AT KLSE BETWEEN 14Z-17Z
INTO THE 1-3SM RANGE. EXPECT CEILINGS TO REMAIN IFR AT KRST UNTIL
17Z THEN RISE INTO THE MVFR CATEGORY. AT KLSE...CEILINGS WILL
REMAIN IN THE MVFR CATEGORY. THE SNOW WILL TAPER OFF EARLY THIS
AFTERNOON...BUT THE MVFR CEILINGS WILL CONTINUE THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
928 AM CDT MON MAR 11 2013
WI...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR WIZ017-029-032>034.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR WIZ041.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ042.
MN...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR MNZ079-087-088-094-
095.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR MNZ096.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ086.
IA...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR IAZ008-009-018-019.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR IAZ010-029.
&&
$$
SHORT TERM...DAS
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
627 AM CDT MON MAR 11 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
346 AM CDT MON MAR 11 2013
AT 3 AM...THE SURFACE LOW WAS OVER NORTHERN LAKE MICHIGAN. THE
850 MB LOW TRACKED 50 TO 100 MILES FURTHER NORTH THAN ORIGINALLY
ADVERTISED. THIS BROUGHT THE DRY SLOT INTO SOUTHWEST AND CENTRAL
WISCONSIN AND PARTS OF NORTHEAST IOWA...THUS CUTTING OFF MUCH OF
THE PRECIPITATION IN THESE AREAS. IT ALSO SHIFTED THE DEFORMATION
AREA FURTHER NORTH INTO SOUTHEAST MINNESOTA AND NORTH CENTRAL
WISCONSIN. THE 11.00Z MODELS ARE IN GOOD AGREEMENT THAT THE
DEFORMATION AXIS WILL BECOME ORIENTATED NORTH-SOUTH EARLY THIS
MORNING AND THEN MOVE SLOWLY EAST AND WEAKEN AS IT MOVES ACROSS
THE FORECAST AREA. ADDITIONAL SNOW AMOUNTS WILL BE LESS THAN
2 INCHES. WITH VERY LITTLE SNOW FALLING SOUTHEAST OF A MAUSTON
WISCONSIN TO OELWEIN IOWA LINE...DROPPED THE WINTER WEATHER
ADVISORIES AND WARNINGS IN THESE AREAS. ALSO...DOWNGRADED THE
WINTER STORM WARNING TO A WINTER WEATHER ADVISORY FOR FAYETTE AND
WINNESHIEK COUNTIES IN NORTHEAST IOWA...HOUSTON COUNTY IN
SOUTHEAST MINNESOTA...AND LA CROSSE AND MONROE COUNTIES IN
WEST-CENTRAL WISCONSIN.
FOR TONIGHT...ANOTHER WEAK WAVE WILL MOVE ACROSS EAST ACROSS THE
AREA. THIS SYSTEM WILL BRING SOME LIGHT SNOW TO THE AREA...BUT
THERE WILL BE LITTLE...IF ANY...ACCUMULATIONS FROM IT.
ON TUESDAY...A MUCH STRONGER SHORT WAVE TROUGH WILL MOVE EAST
THROUGH THE FORECAST AREA. DURING THE LATE MORNING AND AFTERNOON...
950-850 MB LAPSE RATES CLIMB TO AROUND 9C/KM AND CAPES WILL CLIMB
UP 100 J/KG. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
SHOWERS. SOUNDINGS SUGGEST TEMPERATURES WILL BE COLD ENOUGH ALOFT
FOR THE PRECIPITATION TO BE IN THE FORM OF SNOW.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
346 AM CDT MON MAR 11 2013
A FAIRLY ACTIVE NORTHWEST FLOW REMAINS ACROSS THE AREA THROUGH
THIS TIME PERIOD. SHORT WAVES WILL BRING CHANCES OF PRECIPITATION
ON THURSDAY...FRIDAY AND FRIDAY NIGHT...AND SUNDAY AND SUNDAY
NIGHT. THE PRECIPITATION TYPES DURING THIS TIME FRAME IS HIGHLY
DEPENDENT ON WHERE THE BAROCLINIC ZONE SETS UP. THEREFORE JUST
WENT WITH A MIX OF RAIN AND SNOW FOR THESE TIME PERIODS.
&&
.AVIATION...TODAY AND TONIGHT
627 AM CDT MON MAR 11 2013
AN ELONGATED AREA OF LOW PRESSURE WAS LOCATED FROM NORTHERN
ILLINOIS INTO EASTERN WISCONSIN. DEFORMATION BAND OF SNOW WAS
LOCATED OVER NORTHEAST IOWA INTO SOUTHEAST MINNESOTA...AFFECTING
THE KRST TAF SITE WITH 1 1/2SM VISIBILITY IN SNOW. 11.08Z HRRR SHOWS
THIS BAND TO TRANSLATE EASTWARD THIS MORNING AS THE LOW PULLS
AWAY. THUS EXPECT VISIBILITIES TO DROP AT KLSE BETWEEN 14Z-17Z
INTO THE 1-3SM RANGE. EXPECT CEILINGS TO REMAIN IFR AT KRST UNTIL
17Z THEN RISE INTO THE MVFR CATEGORY. AT KLSE...CEILINGS WILL
REMAIN IN THE MVFR CATEGORY. THE SNOW WILL TAPER OFF EARLY THIS
AFTERNOON...BUT THE MVFR CEILINGS WILL CONTINUE THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
346 AM CDT MON MAR 11 2013
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ041-
042.
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ079-
086>088-094-095.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ096.
IA...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR IAZ008-009-
018-019.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR IAZ010-
029.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EDT WED MAR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EDT WED MAR 13 2013
WV IMAGERY AND RUC ANALYSIS UPPER TROUGH IS STILL ROTATING OVER THE
GREAT LAKES REGION THIS MORNING. THE ABUNDANT MOISTURE WITH THIS
UPPER LOW AND 850MB TEMPERATURES AROUND -16C LED TO MODERATE TO
HEAVY LAKE EFFECT SNOW OFF LAKE SUPERIOR YESTERDAY INTO THE
OVERNIGHT HOURS. AS OF 2AM...THE SNOWFALL TOTAL AT OUR OFFICE HAD
REACHED 8.7 INCHES. BUT MID LEVEL DRYING...SEEN ON THE 00Z KINL AND
CWPL SOUNDINGS ALONG WITH IR SATELLITE OVER WESTERN LAKE
SUPERIOR...HAD BROUGHT A QUICK END TO THE SNOW OVER THE WESTERN CWA
SHORTLY AFTER MIDNIGHT AND RECENT RADAR TRENDS OVER THE CENTRAL AND
EAST SHOW SIMILAR QUICK DECREASE.
UPPER RIDGE AND SURFACE HIGH PRESSURE WILL BE BUILDING IN TODAY AND
REMAINING INTO TONIGHT. THIS WILL CONTINUE TO PULL THE DRY AIR OVER
THE AREA AND SHOULD BRING AN END TO THE LINGERING SNOW SHOWERS OVER
THE EAST DURING THE MORNING HOURS. WITH THE QUICK DECREASE TO THE
SNOW...DECIDED TO DROP THE REMAINING WINTER WX ADVISORIES OVER THE
EAST. THE GUSTY WINDS TODAY WILL KEEP SOME BLOWING SNOW IN THE
FORECAST...WITH THE BEST CHANCES NEAR LAKE SUPERIOR EAST OF
MARQUETTE.
BASED ON LATEST TRENDS...HAVE OPTED TO GO MORE A LITTLE MORE
OPTIMISTIC ON THE CLOUD COVER FOR TODAY. THE QUICK TRANSITION TO
VFR AND MID CLOUDS OVER THE WEST SHOWS A LACK OF LOW LEVEL MOISTURE
EVENTHOUGH 850MB TEMPS ARE STILL AROUND -14C. THERE IS JUST ENOUGH
TERRAIN ENHANCEMENT TO AID CLOUD COVER OVER THE WEST AND THAT COULD
BE THE CASE TODAY...ESPECIALLY WITH SOME DIURNAL HEATING HELP.
THUS...AFTER THE DEEPER MOISTURE DEPARTS THIS
MORNING...TRANSITIONED TO A PARTLY CLOUDY SKY WITH THE GREATEST
CLEARING NEAR THE WISCONSIN BORDER. HIGHS TODAY WILL REMAIN BELOW
NORMAL WITH MOST LOCATIONS IN THE MID-UPPER 20S.
FOR TONIGHT...MODELS STILL HINTING AT A INCREASE IN THE MOISTURE IN
THE 925-875MB RANGE LATE THIS AFTERNOON INTO THIS EVENING FROM THE
KEWEENAW SOUTHEAST THROUGH MARQUETTE/ALGER COUNTIES. 875MB TEMPS
AROUND -12.5C WOULD SUPPORT ENOUGH INSTABILITY FOR SOME SNOW
SHOWERS...BUT CONCERN IS THE DEPTH OF THE CLOUD LAYER WHICH WILL
LIKELY ONLY BE 2-3KFT. THERE WAS A THIN AREA OF CLOUDS THIS PAST
EVENING WHERE THE MODELS ARE SHOWING THE LOW MOISTURE...BUT IT HAS
SINCE DISSIPATED. THAT MOISTURE MAY STILL BE PRESENT AND WITH THE
INFLUENCE OF LAKE SUPERIOR...PUT IN A MENTION OF ISOLATED
FLURRIES FOR ALGER/LUCE/SCHOOLCRAFT COUNTIES.
OTHERWISE...HIGH PRESSURE SHOULD BE IN PLACE OVER THE AREA AND LEAD
TO A QUIET NIGHT. THE WESTERN CWA WILL LIKELY BE MOSTLY CLEAR
DURING THE EVENING HOURS BEFORE MID/HIGH CLOUDS START STREAMING IN
AHEAD OF THE NEXT SHORTWAVE DROPPING THROUGH THE NORTHWEST FLOW
ALOFT. THINKING THE HIGH CLOUDS WILL BE IN BY MIDNIGHT AND THEN
THEY WILL THICKEN/LOWER THROUGH THE NIGHT AND COVER ALL OF THE
WESTERN CWA BY MORNING. THIS GIVES CONCERN TO LOWS FOR TONIGHT...AS
THE CLOUD COVER WILL HAVE A GREAT INFLUENCE ON TEMPERATURES WITH THE
OTHERWISE GOOD RADIATIONALLY COOLING NIGHT WITH LIGHT WINDS AND
PWATS AROUND 50 PERCENT OF NORMAL. THE REGIONAL GEM...WHICH USUALLY
DOES WELL IN THESE RADIATIONAL AND CLOUD SITUATIONS HAS LOWS AROUND
ZERO AROUND IRON COUNTY AND THAT COMBINED WITH THE PREVIOUS FORECAST
SEEMS LIKE THE WAY TO GO. UNFORTUNATELY IN THESE SITUATIONS...AN
HOUR OR TWO DIFFERENCE IN CLOUD COVER TIMING CAN EASILY BUST THE
FORECAST IN EITHER DIRECTION.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 447 AM EDT WED MAR 13 2013
UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S.
WITH A TROUGH OVER THE EASTERN U.S. 12Z THU. THE RIDGE GETS
FLATTENED WITH TIME ON FRI WITH A SHORTWAVE MOVING INTO THE NORTHERN
PLAINS LATE FRI. NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE
AND DEEPER MOISTURE MOVING IN ON FRI AND FRI NIGHT.
FOR THIS FORECAST...NOT REAL CONFIDENT IN THE STORM SYSTEM FOR
FRIDAY FOR NOW. ECMWF AND GFS ARE TAKING THE SYSTEM A BIT FURTHER
SOUTH WHILE THE NAM IS NORTH WITH IT. NO REAL CONTINUITY IN THE
MODELS EITHER WITH THEIR FORECASTS...SO CONFIDENCE IS FAIRLY LOW.
WITH THE DIFFERENCE IN PLACEMENT OF THE SYSTEM...THIS WILL AFFECT
HOW COLD 850 MB TEMPERATURES ARE. 12Z ECMWF WAS MUCH WARMER AT 850
MB WITH TEMPERATURES OF -4C TO -8C ON FRI. 00Z ECMWF NOW IS COLDER
WITH 850 MB TEMPERATURES -8C TO -14C WHILE THE GFS IS -10C TO -12C.
WITH NORTH WINDS AND DELTA-T GREATER THAN 11C...THIS IS ENOUGH FOR
LAKE ENHANCEMENT OF THE SNOW. COULD SEE UP TO 5 INCHES OF SNOW ON
FRIDAY INTO FRIDAY NIGHT AND WILL PROBABLY NEED SOME HEADLINES UP
FOR FRIDAY AND FRIDAY NIGHT. WENT LIKELY POPS ON FRIDAY FOR THE LAKE
ENHANCEMENT. FOR THU...LOOKS LIKE A SYSTEM WILL STAY TO THE WEST OF
THE AREA AND ENDED UP GOING DRIER FOR THE FORECAST AS 850 MB
TEMPERATURES ARE NOT COLD ENOUGH FOR LAKE ENHANCEMENT.
OVERALL...LOWERED HIGH TEMPERATURES A COUPLE DEGREES ALONG WITH
OVERNIGHT LOWS DUE TO TRENDS LATELY WHERE FORECASTS HAVE BEEN TOO
WARM.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
NORTHERN U.S. 12Z SAT. THIS TROUGH REMAINS OVER THE AREA ON SUN. A
TROUGH DIGS IN THE NORTHERN PLAINS ON MON AND AFFECTS THE UPPER
GREAT LAKES MON NIGHT INTO TUE. TEMPERATURES CONTINUE TO LOOK COLDER
THAN NORMAL THROUGH THE PERIOD WITH NO WARM UP IN SIGHT. WITH COLD
TEMPERATURES IN PLACE...LAKE EFFECT SNOW WILL BE POSSIBLE THIS
EXTENDED PERIOD FOR SAT AND SUNDAY. ANOTHER SYSTEM ARRIVES FOR MON
INTO TUE AND BRINGS A CHANCE FOR SNOW. THIS SYSTEM WILL HAVE TO BE
WATCHED AS COULD BE ANOTHER SIGNIFICANT WINTER STORM AND WILL HIT UP
THIS POTENTIAL IN THE HWO PRODUCT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EDT WED MAR 13 2013
WITH DISTURBANCE/TROF EXITING...DRIER AIR IS FLOWING INTO THE
AREA...RESULTING IN MUCH IMPROVED CONDITIONS FROM EARLIER IN THE
NIGHT. AT KIWD/KCMX/KSAW...MVFR/VFR CONDITIONS SHOULD PREVAIL OVERNIGHT.
SOME LINGERING SHSN ARE POSSIBLE FOR THE NEXT FEW HRS AT KSAW...BUT
SHOULD ONLY RESULT IN BRIEF REDUCTION OF VIS BLO MVFR. WITH CONTINUED
DRYING...MVFR CIGS SHOULD TEND TO SCATTER OUT TODAY OR LIFT JUST
ABOVE 3KFT...AND THAT COULD HAPPEN AS EARLY AS THE MORNING HRS. VFR
CONDITIONS WILL ROUND OUT THE FCST DURING THE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EDT WED MAR 13 2013
A SURFACE TROUGH THAT DROPPED SOUTH ACROSS LAKE SUPERIOR LAST NIGHT
WILL CONTINUE TO PRODUCE NORTHWEST WINDS OF 20-30KTS OVER THE
EASTERN LAKE TODAY. BUT WITH THE PARENT LOW MOVING NORTHEAST THROUGH
QUEBEC...THIS TIGHT PRESSURE GRADIENT WILL WEAKEN THIS AFTERNOON AS
HIGH PRESSURE MOVES OVER THE LAKE TONIGHT. WINDS HAVE DROPPED
BELOW GALES AT OBSERVATION SITES AND HAVE DROPPED THE GALE WARNING.
THERE COULD STILL BE A FEW GALE FORCE GUSTS OVER THE EASTERN LAKE
DURING THE MORNING...BUT THE COVERAGE SHOULD BE LIMITED. TONIGHT/S
HIGH WILL BEGIN TO SHIFT EAST ON THURSDAY...ALLOWING A COLD FRONT TO
DROP SOUTHEAST ACROSS LAKE SUPERIOR ON THURSDAY NIGHT. A SECONDARY
LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST FROM THE UPPER MISSISSIPPI
VALLEY TO THE LOWER GREAT LAKES ON FRIDAY INTO FRIDAY
NIGHT...SHIFTING WINDS TO A NORTHERLY DIRECTION AT 15-30KTS. BEHIND
THIS LOW...A LARGE AREA OF HIGH PRESSURE WILL MOVE INTO THE UPPER
GREAT LAKES FOR SATURDAY. ANOTHER WEAK TROUGH WILL MOVE ACROSS LAKE
SUPERIOR ON SATURDAY NIGHT BEFORE THE HIGH PRESSURE RIDGE RESETS
OVER THE UPPER GREAT LAKES.
THERE WILL BE FREEZING SPRAY OVER CENTRAL AND EASTERN LAKE SUPERIOR
THROUGH THIS EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...ROLFSON/SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 AM EDT WED MAR 13 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER THE GREAT LKS BTWN UPR RDGS ALONG THE W COAST AND OFF
THE E COAST. WITH DEEP CYC NW FLOW...ABUNDANT MSTR SHOWN ON THE 12Z
GRB RAOB...AND H85 TEMPS IN THE -13C TO -16C RANGE...SHSN HAVE BEEN
COMMON OVER THE CWA TODAY UNDER CLDY SKIES...ESPECIALLY NEAR LK SUP
IN AREAS FAVORED BY THE NW LLVL FLOW. THE SN HAS BEEN RATHER FLUFFY
AS MODEL SDNGS INDICATE THE DGZ IS SEVERAL THOUSAND FEET DEEP GIVEN
FVRBL H85 TEMPS. THERE IS A SHRTWV DROPPING SEWD THRU MN ACCOMPANIED
BY A FAIRLY WELL DEFINED TROF AT H85-7. UPSTREAM OBS AT GRAND MARAIS
ON THE MN NORTH SHORE AND AT THUNDER BAY IN ONTARIO INDICATE SOME
HEAVIER SHSN ACCOMPANY THIS TROF PASSAGE FARTHER TO THE E-SE AWAY FM
DRIER AIR SHOWN ON THE 12Z INL/YPL RAOBS. APRCHG FCST ISSUANCE...
SOME OF THE HEAVIER SHSN HAVE ARRIVED OVER THE WRN COUNTIES. CMX HAS
REPORTED VSBY DOWN TO 1/4SM AT TIMES...AND REPORTS FM GOGEBIC COUNTY
INDICATE AS MUCH AS 5 INCHES OF SN FELL THERE THRU 18Z.
LATE THIS AFTN/TNGT...AS SHRTWV IN MN DIGS SEWD...GUIDANCE SHOWS
PRONOUNCED H85 WSHFT ASSOCIATED WITH TROF PASSAGE AS WELL AS AREA OF
H85-5 QVECTOR CNVGC CROSSING THE CWA NW-SE. EXPECT SHSN TO INCRS IN
INTENSITY WITH THIS ENHANCED SUPPORT IN PRESENCE OF DEEP MSTR. FCST
SDNGS CONTINUE TO SHOW UVV FOCUSED IN THE DGZ...SO EXPECT HI SN/
WATER RATIOS AOA 20:1. LATER TNGT IN THE WAKE OF THE TROF PASSAGE...
DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE OF THE SHRTWV/TROF WL
CONSPIRE TO LOWER INVRN BASES DOWN TO 2-3K FT AGL. WITH ARRIVAL OF
LLVL DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS...EXPECT LES TO DIMINISH
FAIRLY STEADILY AFT 06Z. OVERALL...SHIFTING WINDS FM NW TO N AND
LIMITED 6-9HR WINDOW OR SO FOR HEAVIER SHSN WL LIMIT TOTAL SN
FALL...SO EXPECT SN TOTALS TO REMAIN WITHIN ADVY LIMITS DESPITE
FVRBL SN/WATER RATIOS. THGE ONLY EXCEPTION IS OVER THE FAR W...WHERE
SOME HEAVY SN FELL DURING THE AFTN AS NOTED ABV. SINCE THERE WL BE
PERIODS OF +SHSN THRU THIS EVNG IN THAT AREA WITH SOME FOCUSED LLVL
CNVGC IN FVRBL CYC NNW FLOW...OPTED TO UPGRADE ADVY TO A WARNING FOR
GOGEBIC/ONTONAGON COUNTIES. ALSO EXTENDED ADVY OVER THE ERN ZNS THRU
12Z GIVEN MORE PERSISTENT FORCING/DEEPER MSTR THERE.
WED...AXIS OF MUCH DRIER AIR WITH H85 DEWPTS AS LO AS -40C AS WELL
AS DEEP LYR QVECTOR DVGC/SUBSIDENCE UNDER STEADILY RISING H5 HGTS
FOLLOWING SHIFT OF UPR TROF AXIS TO THE E WL RESULT IN MAINLY DRY WX
AFTER LINGERING SHSN OVER MAINLY THE E DIMINISH IN THE MRNG. IN
FACT...FCST SDNGS SUG SKIES MAY TURN MOSUNNY IN THE AFTN...
ESPECIALLY NEAR LK SUP WITH A TENDENCY FOR CLRG OVER THE WATER UNDER
STRENGTHENING LATE WINTER SUNSHINE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
TO START THE LONG TERM PERIOD...OVERVIEW OF LARGE SCALE FEATURES
TROUGH OVER GREAT LAKES AND EASTERN CANADA WITH BROAD RIDGING
EXTENDING WELL UPSTREAM INTO EASTERN PORTION OF PACIFIC OCEAN.
FARTHER UPSTREAM TROUGHING IS PRESENT NORTH OF HAWAII. THAT TROUGH
IS ESSENTIALLY EXTENSION OF TROUGHING RESIDING OVER NORTHERN
PORTIONS OF CANADA ON NORTHERN PORTION OF WESTERN CONUS RIDGE. OVER
TIME...TROUGH OVER GREAT LAKES SYNCS UP WITH TROUGHING OVER NORTHERN
CANADA RESULTING IN FAST AND ACTIVE WEST-NORTHWEST FLOW ACROSS
MOST OF THE CONUS THROUGH THE UPCOMING WEEKEND.
TWO SHORTWAVES PROGGED TO DROP THROUGH IN THIS FLOW PATTERN INTO
THIS WEEKEND. FIRST WAVE ALONG WITH WEAK SFC-H85 LOW-LEVEL WARM AIR
ADVECTION GLANCES UPR LAKES TO WEST ON THURSDAY. WAVE IS DIGGING
INTO THE MEAN TROUGH WHICH FAVORS MORE OF A SOUTH AND/OR WEST TRACK
AND IS PRETTY PROGRESSIVE. ALSO LOOKS LIKE ANY UPPER JET SUPPORT
REMAINS WEST OF UPR MICHIGAN. MODELS VARY WILDLY FROM SOUTH TO NORTH
WHERE THE MOST QPF/SNOW IS EXPECTED. GEM-NH ON SOUTHERN EXTREME...
TRACKING ACROSS IOWA...WHILE NAM IS OVER WESTERN UPR MICHIGAN. NAM
IS ON NORTH EDGE OF EVEN SREF...SO IT IS CERTAINLY AN OUTLIER. GFS
AND ECMWF IN BTWN...BUT ARE STILL MAINLY OVER WISCONSIN. SINCE THERE
IS A SLIGHT EASTWARD TREND IN MODELS...WILL BRING CHANCE POPS OVER
WESTERN CWA ON THURSDAY. OTHER ISSUE...PREVIOUSLY MENTIONED BY MID
SHIFT...IS POSSIBLE FREEZING DRIZZLE LATER THURSDAY INTO THURSDAY
NIGHT. BASED ON FORECAST SOUNDINGS...WI BORDER/SCNTRL...WILL HAVE
BEST CHANCE SEEING THIS ONCE ANY SNOW DECREASES. ELSEWHERE...THINK
TOO MUCH DRIER AIR IS AROUND BLO H85 TO HAVE IN THERE. SINCE AM NOT
CERTAIN WHERE ULTIMATELY THE STEADIER SNOW SETS UP OVR CWA...IF IT
DOES AT ALL...WILL KEEP FZDZ OUT OF FCST.
COUPLE OF SUBTLE THINGS HAPPEN LATER THURSDAY INTO THURSDAY NIGHT
THAT MAY HAVE LARGE IMPACT ON FORECAST FOR FRIDAY. ALL MODELS INDICATE
STRONGER NORTHERN STREAM WAVE TRACKS WELL TO THE NORTH OVER NORTHWEST
ONTARIO THURSDAY NIGHT. WE ARE GOOD THERE. TROUBLE IS THAT SAME
MODELS DIFFER ON HOW FAR SOUTH TO BRING LOW-LEVEL COLD AIR IN WAKE OF
SHORTWAVE BY FRIDAY MORNING. GEM-NH FARTHER SOUTH WITH COLD AIR AND
TRENDS FROM GFS ALSO INDICATE FARTHER SOUTH LOW-LEVEL TEMPERATURE
GRADIENT AT SFC-H85. ECMWF NOT AS COLD THOUGH. LOCATION OF TIGHTER
LOW-LEVEL TEMPERATURE GRADIENT COULD PAVE THE WAY FOR WHERE HEAVIER
QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE AND SFC-H85 LOWS MOVE IN FROM
NORTHERN PLAINS.
THIS SECOND SHORTWAVE IS MUCH STRONGER THAN ONE MOVING THROUGH 24 HR
EARLIER AND HAS POTENTIAL TO BRING WIDESRPEAD SNOW TO UPPER LAKES ON
FRIDAY. WHERE EVER LOW-LEVEL BAROCLINIC ZONE SETS UP THERE ARE
ENHANCING FACTORS THAT MAY RESULT IN SWATH OF MODERATE TO HEAVY SNOW
INCLUDING DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK
DROPPING INTO GREAT LAKES FROM ONTARIO...DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS OVR 3G/KG...AND OVERALL STRENGTHENING SFC-H85
LOWS/LOW-LEVEL FLOW. ADVY LEVEL SNOWS CERTAINLY POSSIBLE. INCREASED
POPS TO LIKELY OVER WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER
THAT SNOW OCCURS. WWD DAY 3 GRAPHICS INDICATE UP TO 4 INCHES OVER
WEST THIRD OF CWA ON FRIDAY. IF FARTHER NORTH ECMWF AND GEM-NH ARE
CORRECT...THEN LIKELY POPS WILL BE NEEDED FOR MOST AREAS ON FRIDAY.
AT FIRST GLANCE A MAINLY QUIET WEEKEND AS HIGH PRESSURE IS MAIN
FEATURE OVER REGION. COULD BE RE-INFORCING SHOT OF COLDER AIR AND
SOME DEEPER MOISTURE COME IN LATER SATURDAY AND SATURDAY NIGHT.
GFS/ECMWF INDICATE INCREASE IN POPS DURING THAT TIME. KEPT CHANCY
POPS IN ALONG LK SUPERIOR WITH ADDED POTENTIAL FOR LK EFFECT AS H85
TEMPS DROP INTO THE -15C TO -20C RANGE. RECORD SETTING WARMTH OF MID
MARCH IN 2012 WILL BE BUT A DISTANT MEMORY COMPARED TO THE CHILL OF
THIS YEAR.
COOL AND ACTIVE PATTERN CONTINUES INTO EARLY NEXT WEEK...AND
PROBABLY EVEN INTO LATER MARCH AS WELL. CERTAINLY NOT DONE WITH
WINTER YET. DEEPER SHORTWAVE TROUGH EMERGES FROM TROUGHING OVER
NORTHERN CANADA AND EVENTUALLY TRACKS ACROSS ROCKIES LATE IN THE
WEEKEND. THIS TROUGH THEN DEEPENS ACROSS THE MIDDLE CONUS MONDAY AND
MOVES INTO THE GREAT LAKES ON TUESDAY. DEEPENING LOW PRESSURE SYSTEM
RESULTS WHICH DRAWS UP GULF MOISTURE AND COULD LEAD TO SIGNIFICANT
SNOW SOMEWHERE UPPER MIDWEST THROUGH THE GREAT LAKES...INCLUDING UPR
MICHIGAN. OVERALL THE ECMWF IS DEEPER AND FARTHER NORTH WITH SFC
LOW...THOUGH LATEST RUN BACKED OFF WITH STRENGTH OF LOW. GFS IS MORE
SUPPRESSED WITH TRACK OF SFC LOW. WPC...FORMALLY HPC...HAND DRAWN
PROGS BTWN THE TWO WITH LOW MOVING ACROSS LOWER LAKES AND UPR
MICHIGAN JUST ON THE FRINGE. CONSENSUS POPS ARE IN THE CHANCE RANGE
WHICH IS FINE AT THIS POINT. GIVEN NORTHEAST WINDS AND COOLER
AIR...INCREASED POPS CLOSER TO LK SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EDT WED MAR 13 2013
WITH DISTURBANCE/TROF EXITING...DRIER AIR IS FLOWING INTO THE
AREA...RESULTING IN MUCH IMPROVED CONDITIONS FROM EARLIER IN THE
NIGHT. AT KIWD/KCMX/KSAW...MVFR/VFR CONDITIONS SHOULD PREVAIL OVERNIGHT.
SOME LINGERING SHSN ARE POSSIBLE FOR THE NEXT FEW HRS AT KSAW...BUT
SHOULD ONLY RESULT IN BRIEF REDUCTION OF VIS BLO MVFR. WITH CONTINUED
DRYING...MVFR CIGS SHOULD TEND TO SCATTER OUT TODAY OR LIFT JUST
ABOVE 3KFT...AND THAT COULD HAPPEN AS EARLY AS THE MORNING HRS. VFR
CONDITIONS WILL ROUND OUT THE FCST DURING THE EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE MAR 12 2013
UNDER THE TIGHTENING PRES GRADIENT IN THE WAKE OF A TROF PASSAGE
THIS EVENING...EXPECT A N GALE UP TO 35 KTS OVER PORTIONS OF
NCENTRAL LAKE SUP MUCH OF TONIGHT. FREEZING SPRAY WILL BE
WIDESPREAD. AS THE GRADIENT WEAKENS LATE TONIGHT THRU WED...THE
WINDS WILL GRADUALLY DIMINISH AND BACK TOWARD THE NW WITH APPROACH
OF HI PRES FROM THE W. WINDS OF LESS THAN 20 KTS PERSIST INTO
THURSDAY AS HIGH PRESSURE SLIDES ACROSS. SOUTHWESTERLY RETURN FLOW
ON BACK SIDE OF HIGH MAY GET GUSTY OVER 25 KTS BY THU NIGHT. COLD
FRONT SHIFTS THROUGH OVERNIGHT THURSDAY NIGHT WITH NORTHWEST WINDS
TRYING TO REACH 30 KTS. NORTHERLY WINDS TO 25 KTS CONTINUE INTO FRI.
WINDS DIMINISH THROUGH REST OF WEEKEND AS HIGH PRESSURE RETURNS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 2 AM EDT /1 AM CDT/ EARLY THIS
MORNING FOR MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT EARLY THIS MORNING FOR
MIZ001-003-004-084.
WINTER WEATHER ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
MIZ005.
LAKE SUPERIOR...
GALE WARNING UNTIL 5 AM EDT EARLY THIS MORNING FOR LSZ243-244-
248>250-264>266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON/SRF
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1152 PM CDT TUE MAR 12 2013
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THE SC DECK THAT WAS
AFFECTING THE TAF SITES EARLIER THIS EVENING HAS SHIFTED EAST
LEAVING GENERALLY CLEAR SKIES CURRENTLY. SOME MID AND HIGH LEVEL
CLOUDS WILL INCREASE TOWARD MORNING...BUT THESE ARE EXPECTED TO BE
AOA 8 K FT. WINDS WILL CONTINUE TO DIMINISH OVERNIGHT BEFORE
BECOMING SOUTH ON WED WITH SPEEDS BELOW 12 KT.
&&
.PREV DISCUSSION... /ISSUED 325 PM CDT TUE MAR 12 2013/
SHORT TERM...TONIGHT THROUGH FRIDAY.
MOSTLY CLOUDY CONDITIONS HAD DEVELOPED THROUGH THE DAY IN THE
NORTHEASTERN 2/3 OF THE FORECAST AREA...WITHIN AN AREA CYCLONIC
NORTHWESTERLY FLOW AROUND STRONG CLOSED LOW PRESSURE ACROSS THE
WESTERN GREAT LAKES. A FEW FLURRIES HAD DEVELOPED IN NORTHEAST
NEBRASKA AND NORTHWEST IOWA...BUT MORE IMPORTANTLY...WINDS GUSTING
30 TO 35 MPH HAS ALSO CREATED AREAS OF BLOWING SNOW OUT IN OPEN
RURAL AREAS. THIS WAS CREATING SOME VISIBILITY ISSUES...AS WELL
AS SOME SLICK ROADWAYS. THIS TREND WILL CONTINUE THROUGH EARLY
EVENING UNTIL THE WINDS BEGIN TO DIMINISH BY 5 TO 7 PM...ALTHOUGH
ISOLATED FLURRIES COULD STILL BE POSSIBLE IN WESTERN IOWA FOR
ANOTHER HOUR OR TWO BEYOND THAT. CLOUD TRENDS OVERNIGHT WILL BE
ALSO BE TRICKY TO FORECAST. SURFACE HIGH PRESSURE RIDGE WILL
CONTINUE MOVING IN FROM THE WEST. THIS WILL ALLOW SOME OF THE
DIURNAL CLOUDS TO DISSIPATE ON THE SOUTHWEST EDGE...HOWEVER AS
WITH PAST SEVERAL SYSTEMS...THE RAP SEEMS TO HAVE A MUCH BETTER
HANDLE ON THE LOW LEVEL CLOUDINESS...LINGERING IT MUCH LONGER THAN
OTHER MODELS WOULD SUGGEST. THIS COULD ALSO AFFECT HOURLY
TEMPERATURES...AS SKIES CLEAR IN SOME AREAS AND WINDS BECOME LIGHT
AND PERHAPS EVEN CALM IN OUR WESTERN CWA. SOME CIRRUS COULD ALSO
BEGIN TO MOVE INTO THESE SAME AREAS TOWARD DAYBREAK...AS AREAS
ALONG/EAST OF THE MISSOURI RIVER FINALLY BEGIN TO SCATTER OUT.
SOUTHEASTERLY SURFACE FLOW DEVELOPS ON WEDNESDAY AS THE MID/HIGH
CLOUDS MOVE ACROSS THE REGION. TEMPS SHOULD WARM INTO THE MID 30S
OVER THE SNOWFIELD, AND THE LOWER/MID 40S ELSEWHERE.
MEANWHILE...WARM AIR ADVECTION ALOFT WILL CONTINUE THROUGH THE
REMAINDER OF THE PERIOD. ANOTHER WEAK CLIPPER SYSTEM WILL MOVE
THROUGH THE DAKOTAS WEDNESDAY NIGHT. WHILE THIS COULD GENERATE A
SPRINKLE OR TWO IN OUR AREA AND MAYBE EVEN MEASURABLE PRECIP JUST
TO OUR NORTH/NORTHEAST...WILL MAINTAIN A DRY FORECAST AT THIS
TIME WITH PARTLY TO MOSTLY CLOUDY SKIES EXPECTED. THIS SHOULD
TRANSLATE TO DECENT WARMING ON THURSDAY...UPPER 40S OVER THE
DIMINISHING SNOW PACK...WHICH IS STILL UNDER MAV/MET GUIDANCE...
TO THE LOWER 60S OVER THE SNOW FREE AREAS. FRIDAY SHOULD BE THE
WARMEST DAY OF THE WEEK AS TEMPERATURES WARM SIGNIFICANTLY AHEAD
OF THE NEXT COLD FRONT EXPECTED FOR THE WEEKEND. TEMPS FRIDAY
SHOULD REACH THE MID 50S WHERE SOME SNOW STILL EXISTS...AND EVEN
IN THE MID TO UPPER 60S ELSEWHERE.
DEWALD
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
THE EXTENDED PERIOD LOOKS TO BE A PERIOD OF BELOW NORMAL
TEMPERATURES WITH UNSETTLED WEATHER SATURDAY THROUGH MONDAY. WEATHER
DISTURBANCES MOVING THROUGH THE WEST AND NORTHWEST FLOW ALOFT AND
WILL BRING CHANCES OF PRECIPITATION. THE LONG RANGE MODELS ARE NOT
IN GOOD AGREEMENT IN SPECIFIC TIMING AND STRENGTH OF THE
SYSTEMS...THUS LOW CONFIDENCE IN PINNING DOWN THE THERMAL STRUCTURE
AND TIMING. A WEAK WAVE APPEARS TO MOVE THROUGH THE CENTRAL/NORTHER
PLAINS SATURDAY AND SATURDAY NIGHT...AND THE GFS LINGERS IT INTO
SUNDAY...WITH SNOW...SLEET...AND RAIN POSSIBLE. SUNDAY NIGHT INTO
MONDAY...ANOTHER STRONGER SYSTEM MOVES THROUGH. THE EC IS STRONGER
WITH THE WAVE...FARTHER NORTH WITH THE PRECIP AND MOVES IT THROUGH
FASTER WITH MORE COLD AIR AND STRONGER WINDS AVAILABLE. FOR NOW HAVE
CHANCE POPS FOR RAIN OR SNOW MENTIONED FOR SUNDAY NIGHT AND MONDAY.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 AM EDT WED MAR 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD TOWARD THE REGION FROM THE WEST TODAY
THROUGH THURSDAY. A CLIPPER LOW WILL TRACK RAPIDLY SOUTHEAST INTO
THE MID ATLANTIC AND CAROLINAS THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 930 PM TUESDAY...
THROUGH TONIGHT: SKIES HAVE CLEARED ACROSS ALL OF CENTRAL NC AS THE
COLD FRONT WHICH BROUGHT TODAY`S RAIN HAS SHIFTED TO COASTAL
SECTIONS AND IS POISED TO MOVE OFFSHORE... PROPELLED BY COOL HIGH
PRESSURE EXTENDING FROM CENTRAL CANADA DOWN THROUGH THE PLAINS AND
LOWER MISS VALLEY. THE DIFFERENCE BETWEEN THE 00Z SOUNDINGS AT MHX
(SOME LINGERING MOISTURE BELOW 850 MB) AND GSO (VERY DRY AIR THROUGH
THE COLUMN) TELLS THE STORY... AS DOES THE WATER VAPOR IMAGERY
SHOWING WELL THE SLUG OF DRY AIR SWEEPING TO THE NE THROUGH CENTRAL
NC. UPPER LEVEL TRAJECTORIES DO SUGGEST HOWEVER THAT THE HIGH CLOUDS
NOW STREAMING ACROSS ARK AND THE MEMPHIS AREA WILL SWEEP ACROSS NC
TOWARD MIDNIGHT AND DURING THE OVERNIGHT HOURS... ALSO INDICATED BY
THE RAP SOUNDINGS. WILL INCLUDE A THIN VEIL OF CLOUDS OVERNIGHT...
BUT OTHERWISE SKIES SHOULD BE CLEAR. AS THE SURFACE RIDGE BUILDS IN
OVERNIGHT WITH NORTHEASTERLY SURFACE WINDS AND COLD AIR ADVECTION...
THICKNESSES ARE EXPECTED TO PLUMMET... FROM MUCH ABOVE NORMAL
READINGS TODAY TO JUST BELOW NORMAL READINGS BY MORNING... ALTHOUGH
THE MORE SIGNIFICANT DROP COMES WEDNESDAY INTO WEDNESDAY NIGHT WITH
THE ARRIVAL OF THE POLAR FRONT. BOTH TEMPS AND DEW POINTS ARE
TRENDING VERY CLOSE TO THE FORECAST PACE...AND LOWS OF 34-42 STILL
LOOK REASONABLE. -GIH
WEDNESDAY AND WEDNESDAY NIGHT: POTENT SHORTWAVE ENERGY UPSTREAM OVER
MINNESOTA WILL DIG SOUTHEAST INTO THE TN VALLEY TONIGHT AND THEN
THROUGH THE CAROLINAS AND VIRGINIA ON WEDNESDAY. AS THE POTENT
VORTMAX SWINGS THROUGH THE AREA...STRONG DCVA AIDED BY COOLING ALOFT
WILL RESULT IN STRONG MID AND UPPER LEVEL ASCENT. AIRMASS WILL BE
TOO DRY TO SUPPORT OTHER THAN A PERIOD OF A PERIOD OF BROKEN TO
OVERCAST MID CLOUDS WEDNESDAY AFTERNOON. AN ATYPICALLY COLD AIRMASS
ALOFT (H85 TEMPS 1-2 STD DEVIATIONS BELOW NORMAL)IN THE PRESENCE OF
DEEP VERTICAL MIXING WILL RESULT IN BELOW NORMAL TEMPERATURES WITH
BREEZY NWLY WIND GUSTS BETWEEN 20 TO 25KTS. BOTH THE DRY-ADIABATIC
AND LOW-LEVEL THICKNESS TEMPERATURES SCHEME SUGGEST AFTERNOON HIGHS
A GOOD 5 TO 8 DEGREES BELOW STATISTICAL MOS GUIDANCE.
HOWEVER...CONSIDERING THE EVER INCREASING SUN ANGLE THIS TIME OF
YEAR...AM CONCERNED CURRENT FORECAST MAY BE A TOUCH TOO COOL...BUT
THE EXPECTED PERIOD OF BROKEN MID-LEVEL CLOUD COVER SHOULD HELP.
HIGHS NEAR 50 NW TO MID/UPPER 50S SOUTHEAST.
A SECONDARY ROUND OF LOW-LEVEL COLD ADVECTION WILL OCCUR WEDNESDAY
EVENING/NIGHT IN ASSOCIATION WITH RENEWED LOW-LEVEL NWLY FLOW
IN THE WAKE OF THE EXITING UPPER LEVEL TROUGH. MINS FOR THE SECOND
CONSECUTIVE NIGHT WILL BE DRIVEN BY CAA. LOWS WED NIGHT IN THE UPPER
20S TO LOWER 30S. -CBL
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 PM TUESDAY...
A STRONG UPPER LEVEL TROUGH WILL STILL BE IN PLACE ALONG THE EASTERN
US ON THURSDAY. THIS...ALONG WITH CONTINUED COLD AIR ADVECTION
(NORTHWESTERLY WINDS OF 10-15 MPH WILL LEAD TO ANOTHER DAY OF BELOW
NORMAL TEMPS. HIGHS ARE ONLY EXPECTED TO BE IN THE LOW 50S (POSSIBLY
STRUGGLING TO EVEN REACH 50 DEGREES IN SOME LOCATIONS). THE UPPER
LEVEL TROUGH AXIS WILL MOVE OFFSHORE THURSDAY NIGHT...BUT A
DISTURBANCE WITHIN THE NORTHWEST FLOW ALOFT WILL MOVE SOUTHEASTWARD
ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. IT STILL
APPEARS THE MAIN IMPACT FROM THIS FEATURE WILL BE AN INCREASE IN MID
LEVEL CLOUD COVER AS THE BOUNDARY LAYER IS PROGGED TO BE RATHER DRY.
HOWEVER...CANNOT COMPLETELY SOME SPRINKLES OR A LIGHT SHOWER...
ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA. DESPITE
CLOUD COVER...OVERNIGHT LOWS WILL GENERALLY BE WITHIN A DEGREE OR
TWO OF FREEZING. CLOUDS WILL DECREASE THROUGHOUT THE DAY ON FRIDAY
AS SUBSIDENCE INCREASES ON THE BACKSIDE OF THE DEPARTING SHORTWAVE.
AS HEIGHTS INCREASE SOME...TEMPS WILL BEGIN TO MODERATE...WITH
HIGHS IN THE MID/UPPER 50S AND OVERNIGHT LOWS IN THE MID/UPPER 30S
EXPECTED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 250 AM WEDNESDAY...
FRIDAY NIGHT THROUGH SUNDAY NIGHT:
THE H85 RIDGE OVER THE GULF SHOULD DEAMPLIFY AS A LOW PRESSURE
SYSTEM MOVES ACROSS THE GREAT LAKES REGION FRIDAY NIGHT INTO
SATURDAY. A GOOD DEAL OF UNCERTAINTY STILL REMAINS BETWEEN THE 00Z
GFS AND 12Z ECMWF WITH REGARD TO STRENGTH AND TIMING OF THE SYSTEM
AND ASSOCIATED BACKDOOR COLD FRONT...WHICH WILL IN TURN HAVE AN
IMPACT ON TEMPS AND PRECIP THROUGH THE PERIOD. THE ECMWF TENDS TO
AMPLIFY THE TROUGH A BIT MORE THAN THE 00Z GFS... HOWEVER BOTH
MODELS AGREE ON A WEST TO EAST ORIENTED FRONTAL BOUNDARY IN THE
VICINITY OF CENTRAL NC SATURDAY THROUGH SUNDAY NIGHT. THE GFS
PLACES THE FRONT IN THE VICINITY OF THE NC/SC BORDER AND THE ECMWF
PLACES IT FARTHER NORTH...NEAR THE NC/VA BORDER. THIS DIFFERENCE HAS
SIGNIFICANT IMPACTS ON PRECIP LOCATION AND TEMPS FOR THE PERIOD. IN
GENERAL...EXPECT HIGH TEMPS SLIGHTLY ABOVE NORMAL SATURDAY AND...
BASED ON THE GFS FRONTAL POSITIONING...SLIGHTLY BELOW NORMAL ON
SUNDAY. OVERNIGHT LOWS GENERALLY IN THE LOW TO MID 40S. GFS FORECAST
SOUNDINGS INDICATE MOISTURE INCREASING FROM THE TOP DOWN STARTING
SATURDAY...SATURATING THROUGHOUT THE COLUMN FROM NORTH TO SOUTH BY
SUNDAY NIGHT. GIVEN THE CURRENT MODEL DIFFERENCES AND DEGREE OF
UNCERTAINTY...WILL CONTINUE TO LEAN TOWARD THE MORE CONSISTENT GFS
SOLUTION...WITH SLIGHT CHANCE OF RAIN ACROSS THE NORTH BEGINNING
SATURDAY AFTERNOON...EXTENDING ACROSS THE ENTIRE AREA BY SUNDAY.
MONDAY THROUGH TUESDAY:
THE MODELS AGREE THAT A STRONG LOW PRESSURE SYSTEM WILL DEVELOP IN
THE LEE OF THE ROCKIES SUNDAY NIGHT AND DEEPEN AS IT MOVES EAST AND
NORTHEAST THROUGH THE GREAT LAKES TOWARD THE END OF THE PERIOD. AT
THE SURFACE...THE LOW AND ASSOCIATED COLD FRONT WILL PUSH THE HIGH
OUT OF THE NE AND BRING THE CHANCE FOR ANOTHER ROUND OF PRECIP
THROUGH THE AREA. THERE IS SOME INDICATION IN THE MODELS OF A PERIOD
OF LIGHT PRECIP ACROSS THE WEST AHEAD OF THE MAIN SYSTEM...LIKELY
THE PRODUCT OF SOME ISENTROPIC LIFT AS THE ENE RETURN FLOW ADVECTS
LOW LEVEL MOISTURE INTO THE AREA. MODELS ARE TRENDING DRIER WITH THE
FROPA TUESDAY...AS WESTERLY FLOW OFF THE APPALACHIANS INDUCES
SUBSIDENCE. WITH SOME UNCERTAINTY WITH REGARD TO LOCATION OF THE
PARENT LOW AND TIMING OF THE FROPA...WILL CARRY SLIGHT CHANCE OF
RAIN INTO TUESDAY...WITH GFS FORECAST SOUNDINGS INDICATING DRYING
BEHIND IT. HIGH TEMPS MONDAY AND TUESDAY IN THE UPPER 50S NORTH TO
MID 60S SOUTH. LOW TEMPS MONDAY NIGHT IN THE MID TO UPPER 40S...
DECREASING TUESDAY NIGHT BEHIND THE FRONT...MID 30S NORTHWEST TO LOW
40S SOUTHEAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 115 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD IN ASSOCIATION WITH
A DRY AIRMASS IN PLACE OVER THE REGION. NORTHWEST WINDS AT 5-10 KT
WILL PREVAIL THROUGH 12Z THIS MORNING. WINDS WILL BACK TO A MORE
WESTERLY DIRECTION AND INCREASE TO ~15 KT SUSTAINED WITH GUSTS UP TO
~25 KT BY 15-18Z. WINDS WILL VEER TO THE NORTHWEST AT 10-15 KT WITH
GUSTS UP TO 20 KT BY 00Z THIS EVENING...WITH GUSTS BECOMING MORE
SPORADIC IN NATURE OVERNIGHT.
LOOKING AHEAD:
VFR CONDITIONS AND A NORTHWEST BREEZE WILL PERSIST ON THURSDAY. A
FAST MOVING CLIPPER LOW WILL TRACK SOUTHEAST THROUGH THE CAROLINAS
THURSDAY NIGHT AND EARLY FRIDAY MORNING...HOWEVER...AT THIS TIME
ANTICIPATE THAT CEILINGS WILL REMAIN AT OR ABOVE 4-5 KFT AGL. VFR
CONDITIONS WILL PERSIST THROUGH FRIDAY NIGHT...WITH THE NEXT CHANCE
OF SUB-VFR CONDITIONS ON SAT/SUN IN ASSOCIATION WITH A COLD FRONT
EXPECTED TO MOVE INTO THE REGION FROM THE NORTH. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...HARTFIELD/CBL
SHORT TERM..KRR
LONG TERM...KC
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
118 AM EDT WED MAR 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD TOWARD THE REGION FROM THE WEST TODAY
THROUGH THURSDAY. A CLIPPER LOW WILL TRACK RAPIDLY SOUTHEAST INTO
THE MID ATLANTIC AND CAROLINAS THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 930 PM TUESDAY...
THROUGH TONIGHT: SKIES HAVE CLEARED ACROSS ALL OF CENTRAL NC AS THE
COLD FRONT WHICH BROUGHT TODAY`S RAIN HAS SHIFTED TO COASTAL
SECTIONS AND IS POISED TO MOVE OFFSHORE... PROPELLED BY COOL HIGH
PRESSURE EXTENDING FROM CENTRAL CANADA DOWN THROUGH THE PLAINS AND
LOWER MISS VALLEY. THE DIFFERENCE BETWEEN THE 00Z SOUNDINGS AT MHX
(SOME LINGERING MOISTURE BELOW 850 MB) AND GSO (VERY DRY AIR THROUGH
THE COLUMN) TELLS THE STORY... AS DOES THE WATER VAPOR IMAGERY
SHOWING WELL THE SLUG OF DRY AIR SWEEPING TO THE NE THROUGH CENTRAL
NC. UPPER LEVEL TRAJECTORIES DO SUGGEST HOWEVER THAT THE HIGH CLOUDS
NOW STREAMING ACROSS ARK AND THE MEMPHIS AREA WILL SWEEP ACROSS NC
TOWARD MIDNIGHT AND DURING THE OVERNIGHT HOURS... ALSO INDICATED BY
THE RAP SOUNDINGS. WILL INCLUDE A THIN VEIL OF CLOUDS OVERNIGHT...
BUT OTHERWISE SKIES SHOULD BE CLEAR. AS THE SURFACE RIDGE BUILDS IN
OVERNIGHT WITH NORTHEASTERLY SURFACE WINDS AND COLD AIR ADVECTION...
THICKNESSES ARE EXPECTED TO PLUMMET... FROM MUCH ABOVE NORMAL
READINGS TODAY TO JUST BELOW NORMAL READINGS BY MORNING... ALTHOUGH
THE MORE SIGNIFICANT DROP COMES WEDNESDAY INTO WEDNESDAY NIGHT WITH
THE ARRIVAL OF THE POLAR FRONT. BOTH TEMPS AND DEW POINTS ARE
TRENDING VERY CLOSE TO THE FORECAST PACE... AND LOWS OF 34-42 STILL
LOOK REASONABLE. -GIH
WEDNESDAY AND WEDNESDAY NIGHT: POTENT SHORTWAVE ENERGY UPSTREAM OVER
MINNESOTA WILL DIG SOUTHEAST INTO THE TN VALLEY TONIGHT AND THEN
THROUGH THE CAROLINAS AND VIRGINIA ON WEDNESDAY. AS THE POTENT
VORTMAX SWINGS THROUGH THE AREA...STRONG DCVA AIDED BY COOLING ALOFT
WILL RESULT IN STRONG MID AND UPPER LEVEL ASCENT. AIRMASS WILL BE
TOO DRY TO SUPPORT OTHER THAN A PERIOD OF A PERIOD OF BROKEN TO
OVERCAST MID CLOUDS WEDNESDAY AFTERNOON. AN ATYPICALLY COLD AIRMASS
ALOFT (H85 TEMPS 1-2 STD DEVIATIONS BELOW NORMAL)IN THE PRESENCE OF
DEEP VERTICAL MIXING WILL RESULT IN BELOW NORMAL TEMPERATURES WITH
BREEZY NWLY WIND GUSTS BETWEEN 20 TO 25KTS. BOTH THE DRY-ADIABATIC
AND LOW-LEVEL THICKNESS TEMPERATURES SCHEME SUGGEST AFTERNOON HIGHS
A GOOD 5 TO 8 DEGREES BELOW STATISTICAL MOS GUIDANCE.
HOWEVER...CONSIDERING THE EVER INCREASING SUN ANGLE THIS TIME OF
YEAR...AM CONCERNED CURRENT FORECAST MAY BE A TOUCH TOO COOL...BUT
THE EXPECTED PERIOD OF BROKEN MID-LEVEL CLOUD COVER SHOULD HELP.
HIGHS NEAR 50 NW TO MID/UPPER 50S SOUTHEAST.
A SECONDARY ROUND OF LOW-LEVEL COLD ADVECTION WILL OCCUR WEDNESDAY
EVENING/NIGHT IN ASSOCIATION WITH RENEWED LOW-LEVEL NWLY FLOW
IN THE WAKE OF THE EXITING UPPER LEVEL TROUGH. MINS FOR THE SECOND
CONSECUTIVE NIGHT WILL BE DRIVEN BY CAA. LOWS WED NIGHT IN THE UPPER
20S TO LOWER 30S. -CBL
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 320 PM TUESDAY...
A STRONG UPPER LEVEL TROUGH WILL STILL BE IN PLACE ALONG THE EASTERN
US ON THURSDAY. THIS...ALONG WITH CONTINUED COLD AIR ADVECTION
(NORTHWESTERLY WINDS OF 10-15 MPH WILL LEAD TO ANOTHER DAY OF BELOW
NORMAL TEMPS. HIGHS ARE ONLY EXPECTED TO BE IN THE LOW 50S (POSSIBLY
STRUGGLING TO EVEN REACH 50 DEGREES IN SOME LOCATIONS). THE UPPER
LEVEL TROUGH AXIS WILL MOVE OFFSHORE THURSDAY NIGHT...BUT A
DISTURBANCE WITHIN THE NORTHWEST FLOW ALOFT WILL MOVE SOUTHEASTWARD
ACROSS THE REGION THURSDAY NIGHT INTO FRIDAY MORNING. IT STILL
APPEARS THE MAIN IMPACT FROM THIS FEATURE WILL BE AN INCREASE IN MID
LEVEL CLOUD COVER AS THE BOUNDARY LAYER IS PROGGED TO BE RATHER DRY.
HOWEVER...CANNOT COMPLETELY SOME SPRINKLES OR A LIGHT SHOWER...
ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA. DESPITE
CLOUD COVER...OVERNIGHT LOWS WILL GENERALLY BE WITHIN A DEGREE OR
TWO OF FREEZING. CLOUDS WILL DECREASE THROUGHOUT THE DAY ON FRIDAY
AS SUBSIDENCE INCREASES ON THE BACKSIDE OF THE DEPARTING SHORTWAVE.
AS HEIGHTS INCREASE SOME...TEMPS WILL BEGIN TO MODERATE...WITH
HIGHS IN THE MID/UPPER 50S AND OVERNIGHT LOWS IN THE MID/UPPER 30S
EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 320 PM TUESDAY...
UNCERTAINTY REMAINS HIGH DURING THE LONG TERM PERIOD. OVERALL...THE
FLOW ALOFT IS PROGGED TO DEAMPLIFY AND TEMPS SHOULD GRADUALLY MODIFY
THROUGH THE WEEKEND. MODELS ARE STILL INDICATING A BACKDOOR FRONT
MOVING INTO THE AREA ON SATURDAY...BUT THERE IS CONSIDERABLE
DISAGREEMENT ON HOW TO HANDLE THIS FRONT. THE LAST COUPLE OF RUNS OF
THE GFS PUSH THE FRONT SOUTH OF THE AREA SATURDAY NIGHT...WHILE THE
ECMWF STALLS THE FRONT SOMEWHERE NEAR THE FORECAST AREA. THIS
CREATES A LOT OF DISAGREEMENT WITH RESPECT TO BOTH PRECIP CHANCES
AND TEMPS. THEN MODELS SHOW A WAVE OF LOW PRESSURE DEVELOPING ON THE
FRONT SUNDAY INTO MONDAY AND TRACKING EAST...ALTHOUGH WHERE EXACTLY
THIS FRONT WILL BE (AND ASSOCIATED LOW TRACK) IS STILL IN QUESTION.
MODELS ARE THEN IN GENERAL AGREEMENT WITH A MORE AMPLIFIED TROUGH
ALOFT MOVING INTO THE MIDWEST ON TUESDAY...WITH AN ASSOCIATED
SURFACE FRONT PROGGED TO CROSS THE REGION TUESDAY/TUESDAY NIGHT.
GIVEN ALL THE UNCERTAINTY WILL NOT CHANGE THE FORECAST TOO
MUCH...WITH SLIGHT CHANCE POPS OVER THE WEEKEND...BEFORE SLIGHTLY
HIGHER POPS FOR EARLY NEXT WEEK. TEMPS ARE EXPECTED TO BE ABOVE
NORMAL ON SATURDAY (AHEAD OF THE BACKDOOR FRONT)...WITH NEAR NORMAL
TEMPS FOR THE REMAINDER OF THE PERIOD (ALTHOUGH IT WILL BE HIGHLY
DEPENDENT ON FRONTAL POSITION).
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 115 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD IN ASSOCIATION WITH
A DRY AIRMASS IN PLACE OVER THE REGION. NORTHWEST WINDS AT 5-10 KT
WILL PREVAIL THROUGH 12Z THIS MORNING. WINDS WILL BACK TO A MORE
WESTERLY DIRECTION AND INCREASE TO ~15 KT SUSTAINED WITH GUSTS UP TO
~25 KT BY 15-18Z. WINDS WILL VEER TO THE NORTHWEST AT 10-15 KT WITH
GUSTS UP TO 20 KT BY 00Z THIS EVENING...WITH GUSTS BECOMING MORE
SPORADIC IN NATURE OVERNIGHT.
LOOKING AHEAD:
VFR CONDITIONS AND A NORTHWEST BREEZE WILL PERSIST ON THURSDAY. A
FAST MOVING CLIPPER LOW WILL TRACK SOUTHEAST THROUGH THE CAROLINAS
THURSDAY NIGHT AND EARLY FRIDAY MORNING...HOWEVER...AT THIS TIME
ANTICIPATE THAT CEILINGS WILL REMAIN AT OR ABOVE 4-5 KFT AGL. VFR
CONDITIONS WILL PERSIST THROUGH FRIDAY NIGHT...WITH THE NEXT CHANCE
OF SUB-VFR CONDITIONS ON SAT/SUN IN ASSOCIATION WITH A COLD FRONT
EXPECTED TO MOVE INTO THE REGION FROM THE NORTH. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...HARTFIELD/CBL
SHORT TERM..KRR
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
404 AM CDT WED MAR 13 2013
.SHORT TERM...TODAY THROUGH THURSDAY...
THE MAIN HIGHLIGHT OF THE SHORT TERM PERIOD IS PRECIPITATION
CHANCES THIS MORNING AND AGAIN TONIGHT.
CURRENTLY...LATEST RADAR REFLECTIVITIES AT 0830Z SHOW SCATTERED
SNOW SHOWERS OVER EASTERN MONTANA THROUGH NORTHWEST SOUTH DAKOTA
ASSOCIATED WITH AN EASTWARD MOVING WARM FRONT. ACROSS THE
WEST...SURFACE OBSERVATIONS OVER THE LAST COUPLE OF HOURS HAVE YET
TO REFLECT ANY SNOW REACHING THE SURFACE. THE 00Z SUITE OF
DETERMINISTIC MODELS ARE IN DISAGREEMENT REGARDING PRECIP AND QPF.
THE 00Z ECWMF/GFS PAINT LIGHT QPF OVER THE WEST OVER THE NEXT FEW
HOURS...WHILE THE NAM/GEM KEEP THE WEST DRY. THE 07Z RAP HAS THE
AREA OF SNOW SHOWERS CONTINUING TO MOVE EAST...BUT THEN STALL AND
DIMINISH ACROSS THE WEST LATER THIS MORNING. FOR NEAR TERM
POPS...HAVE USED A BLEND OF THE GFS/ECWMF/RAP. SNOW ACCUMULATIONS
ARE EXPECTED TO BE UNDER A HALF INCH.
THE AFOREMENTIONED WARM FRONT WILL CONTINUE TO PUSH EAST AND OVER
NORTH DAKOTA TODAY. WITH WARM AIR ADVECTION TAKING
PLACE OVER THE AREA...THERE WILL BE SHARP TEMPERATURE GRADIENT
DEVELOPING. WHERE RECENT SNOW HAS FALLEN AND IS STILL IN
PLACE...TEMPERATURES WILL REMAIN SEASONABLE AND IN THE UPPER 20S
AND LOWER 30S. THE GREATEST WARM UP WILL BE FOR THE SNOWLESS
SOUTHWEST...WHERE TEMPERATURES WILL WARM INTO THE MID TO UPPER 50S.
FOR TONIGHT...A WEAK UPPER LEVEL IMPULSE WILL MOVE ACROSS THE
AREA...BRINGING A PERIOD OF LIGHT PRECIPITATION THROUGH FRIDAY MORNING.
THERE IS DISAGREEMENT BETWEEN THE 00Z MODEL SOLUTIONS...WITH THE
NAM/GEM KEEPING PRECIP FURTHER EAST...THE ECWMF BEING MORE
PROGRESSIVE...AND THE GFS BRINGING LIGHT QPF TO THE AREA. HAVE
UTILIZED A BLEND OF THE 00Z GFS/ECWMF SOLUTIONS. PRECIPITATION
WILL BE IN THE FORM LIGHT RAIN FOR LOCATIONS ALONG THE
MISSOURI...AS THE THERMAL PROFILE WILL BE ABOVE FREEZING...AND AS
LIGHT WINTRY MIX ACROSS THE NORTH. ANY ACCUMULATING SNOW WILL BE
CONFINED TO THE TURTLE MOUNTAINS AND FAR EAST...WHERE OVERNIGHT
TEMPERATURES WILL COOL INTO THE UPPER 20S.
FOR THURSDAY...A DRY AND MILD DAY IS EXPECTED. THURSDAY AFTERNOON
HIGHS WILL BE 10 TO 15 DEGREES WARMER THAN NORMAL FOR THE
SOUTHWEST AND SOUTH CENTRAL...WHERE TEMPERATURES WILL CLIMB INTO
THE MID TO UPPER 50S. FOR THE FAR SOUTHWEST...LOWER 60S ARE A
POSSIBILITY. ELSEWHERE...TEMPERATURES WILL BE IN THE 30S AND 40S.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
FRONTOGENESIS ALONG A BAROCLINIC ZONE OVER NORTHWESTERN NORTH DAKOTA
IS PROGGED TO EXTEND INTO SOUTHEASTERN NORTH DAKOTA THURSDAY NIGHT.
THIS WILL GENERATE CATEGORICAL PRECIP CHANCES NORTH WITH CHANCE POPS
CENTRAL...MAINLY AFTER MIDNIGHT. THE LATEST 00Z MODEL SUITE IS A
LITTLE FASTER THAN PREVIOUS RUNS AND PROGS THE BOUNDARY TO PUSH
SOUTH ACROSS THE STATE FRIDAY MORNING AND INTO SOUTH DAKOTA FRIDAY
AFTERNOON. SUBSEQUENTLY...THE PRECIP TYPE IS PROGGED TO TRANSITION
FROM A WINTRY MIX CENTRAL EARLY FRIDAY MORNING TO ALL SNOW BY MID TO
LATE FRIDAY MORNING. MADE ADJUSTMENTS TO THE HOURLY WX GRIDS
ACCORDINGLY.
THE SNOW CHANCES SHOULD TAPER OFF FROM WEST TO EAST FRIDAY NIGHT AS
HIGH PRESSURE BUILDS INTO THE REGION. A WEAK WAVE IN WESTERLY FLOW
ALOFT IS PROGGED TO GENERATE A SLIGHT CHANCE OF SNOW SATURDAY AND
SATURDAY NIGHT. HOWEVER...ACCUMULATIONS SHOULD BE LIGHT.
A MORE POTENT SHORTWAVE IS THEN PROGGED TO AFFECT THE NORTHERN
PLAINS SUNDAY/SUNDAY NIGHT/MONDAY. THE 00Z ECMWF CONTINUES TO BE
MORE AGGRESSIVE THAN THE GFS/GEM WITH RESPECT TO THE STRENGTH OF
THIS FEATURE. HOWEVER...THE ECMWF IS TRENDING FARTHER SOUTH WITH ITS
TRACK. GIVEN THE MODEL TO MODEL AND RUN TO RUN
INCONSISTENCIES...WENT WITH A BLEND OF SOLUTIONS AND INCREASED POPS
SUNDAY THROUGH MONDAY. HIGH PRESSURE BUILDING INTO THE REGION SHOULD
GENERATE COOL AND DRY CONDITIONS TUESDAY WITH BELOW NORMAL
TEMPERATURES EXPECTED.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE TAF PERIOD. THERE IS A POTENTIAL FOR LOW
VFR CONDITIONS IN STRATUS AND SNOW AFTER 09 UTC ACROSS NORTHWEST
NORTH DAKOTA...POSSIBLY IMPACTING KISN BETWEEN 09 UTC AND 12 UTC.
FURTHERMORE...THERE WILL BE A SLIGHT CHANCE FOR A RAIN/SNOW MIX
NORTH (KISN/KMOT) LATE THIS AFTERNOON. HOWEVER...CONDITIONS SHOULD
REMAIN VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM/AVIATION...TM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
650 AM EDT WED MAR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EDT WED MAR 13 2013
WV IMAGERY AND RUC ANALYSIS UPPER TROUGH IS STILL ROTATING OVER THE
GREAT LAKES REGION THIS MORNING. THE ABUNDANT MOISTURE WITH THIS
UPPER LOW AND 850MB TEMPERATURES AROUND -16C LED TO MODERATE TO
HEAVY LAKE EFFECT SNOW OFF LAKE SUPERIOR YESTERDAY INTO THE
OVERNIGHT HOURS. AS OF 2AM...THE SNOWFALL TOTAL AT OUR OFFICE HAD
REACHED 8.7 INCHES. BUT MID LEVEL DRYING...SEEN ON THE 00Z KINL AND
CWPL SOUNDINGS ALONG WITH IR SATELLITE OVER WESTERN LAKE
SUPERIOR...HAD BROUGHT A QUICK END TO THE SNOW OVER THE WESTERN CWA
SHORTLY AFTER MIDNIGHT AND RECENT RADAR TRENDS OVER THE CENTRAL AND
EAST SHOW SIMILAR QUICK DECREASE.
UPPER RIDGE AND SURFACE HIGH PRESSURE WILL BE BUILDING IN TODAY AND
REMAINING INTO TONIGHT. THIS WILL CONTINUE TO PULL THE DRY AIR OVER
THE AREA AND SHOULD BRING AN END TO THE LINGERING SNOW SHOWERS OVER
THE EAST DURING THE MORNING HOURS. WITH THE QUICK DECREASE TO THE
SNOW...DECIDED TO DROP THE REMAINING WINTER WX ADVISORIES OVER THE
EAST. THE GUSTY WINDS TODAY WILL KEEP SOME BLOWING SNOW IN THE
FORECAST...WITH THE BEST CHANCES NEAR LAKE SUPERIOR EAST OF
MARQUETTE.
BASED ON LATEST TRENDS...HAVE OPTED TO GO MORE A LITTLE MORE
OPTIMISTIC ON THE CLOUD COVER FOR TODAY. THE QUICK TRANSITION TO
VFR AND MID CLOUDS OVER THE WEST SHOWS A LACK OF LOW LEVEL MOISTURE
EVENTHOUGH 850MB TEMPS ARE STILL AROUND -14C. THERE IS JUST ENOUGH
TERRAIN ENHANCEMENT TO AID CLOUD COVER OVER THE WEST AND THAT COULD
BE THE CASE TODAY...ESPECIALLY WITH SOME DIURNAL HEATING HELP.
THUS...AFTER THE DEEPER MOISTURE DEPARTS THIS
MORNING...TRANSITIONED TO A PARTLY CLOUDY SKY WITH THE GREATEST
CLEARING NEAR THE WISCONSIN BORDER. HIGHS TODAY WILL REMAIN BELOW
NORMAL WITH MOST LOCATIONS IN THE MID-UPPER 20S.
FOR TONIGHT...MODELS STILL HINTING AT A INCREASE IN THE MOISTURE IN
THE 925-875MB RANGE LATE THIS AFTERNOON INTO THIS EVENING FROM THE
KEWEENAW SOUTHEAST THROUGH MARQUETTE/ALGER COUNTIES. 875MB TEMPS
AROUND -12.5C WOULD SUPPORT ENOUGH INSTABILITY FOR SOME SNOW
SHOWERS...BUT CONCERN IS THE DEPTH OF THE CLOUD LAYER WHICH WILL
LIKELY ONLY BE 2-3KFT. THERE WAS A THIN AREA OF CLOUDS THIS PAST
EVENING WHERE THE MODELS ARE SHOWING THE LOW MOISTURE...BUT IT HAS
SINCE DISSIPATED. THAT MOISTURE MAY STILL BE PRESENT AND WITH THE
INFLUENCE OF LAKE SUPERIOR...PUT IN A MENTION OF ISOLATED
FLURRIES FOR ALGER/LUCE/SCHOOLCRAFT COUNTIES.
OTHERWISE...HIGH PRESSURE SHOULD BE IN PLACE OVER THE AREA AND LEAD
TO A QUIET NIGHT. THE WESTERN CWA WILL LIKELY BE MOSTLY CLEAR
DURING THE EVENING HOURS BEFORE MID/HIGH CLOUDS START STREAMING IN
AHEAD OF THE NEXT SHORTWAVE DROPPING THROUGH THE NORTHWEST FLOW
ALOFT. THINKING THE HIGH CLOUDS WILL BE IN BY MIDNIGHT AND THEN
THEY WILL THICKEN/LOWER THROUGH THE NIGHT AND COVER ALL OF THE
WESTERN CWA BY MORNING. THIS GIVES CONCERN TO LOWS FOR TONIGHT...AS
THE CLOUD COVER WILL HAVE A GREAT INFLUENCE ON TEMPERATURES WITH THE
OTHERWISE GOOD RADIATIONALLY COOLING NIGHT WITH LIGHT WINDS AND
PWATS AROUND 50 PERCENT OF NORMAL. THE REGIONAL GEM...WHICH USUALLY
DOES WELL IN THESE RADIATIONAL AND CLOUD SITUATIONS HAS LOWS AROUND
ZERO AROUND IRON COUNTY AND THAT COMBINED WITH THE PREVIOUS FORECAST
SEEMS LIKE THE WAY TO GO. UNFORTUNATELY IN THESE SITUATIONS...AN
HOUR OR TWO DIFFERENCE IN CLOUD COVER TIMING CAN EASILY BUST THE
FORECAST IN EITHER DIRECTION.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 447 AM EDT WED MAR 13 2013
UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S.
WITH A TROUGH OVER THE EASTERN U.S. 12Z THU. THE RIDGE GETS
FLATTENED WITH TIME ON FRI WITH A SHORTWAVE MOVING INTO THE NORTHERN
PLAINS LATE FRI. NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE
AND DEEPER MOISTURE MOVING IN ON FRI AND FRI NIGHT.
FOR THIS FORECAST...NOT REAL CONFIDENT IN THE STORM SYSTEM FOR
FRIDAY FOR NOW. ECMWF AND GFS ARE TAKING THE SYSTEM A BIT FURTHER
SOUTH WHILE THE NAM IS NORTH WITH IT. NO REAL CONTINUITY IN THE
MODELS EITHER WITH THEIR FORECASTS...SO CONFIDENCE IS FAIRLY LOW.
WITH THE DIFFERENCE IN PLACEMENT OF THE SYSTEM...THIS WILL AFFECT
HOW COLD 850 MB TEMPERATURES ARE. 12Z ECMWF WAS MUCH WARMER AT 850
MB WITH TEMPERATURES OF -4C TO -8C ON FRI. 00Z ECMWF NOW IS COLDER
WITH 850 MB TEMPERATURES -8C TO -14C WHILE THE GFS IS -10C TO -12C.
WITH NORTH WINDS AND DELTA-T GREATER THAN 11C...THIS IS ENOUGH FOR
LAKE ENHANCEMENT OF THE SNOW. COULD SEE UP TO 5 INCHES OF SNOW ON
FRIDAY INTO FRIDAY NIGHT AND WILL PROBABLY NEED SOME HEADLINES UP
FOR FRIDAY AND FRIDAY NIGHT. WENT LIKELY POPS ON FRIDAY FOR THE LAKE
ENHANCEMENT. FOR THU...LOOKS LIKE A SYSTEM WILL STAY TO THE WEST OF
THE AREA AND ENDED UP GOING DRIER FOR THE FORECAST AS 850 MB
TEMPERATURES ARE NOT COLD ENOUGH FOR LAKE ENHANCEMENT.
OVERALL...LOWERED HIGH TEMPERATURES A COUPLE DEGREES ALONG WITH
OVERNIGHT LOWS DUE TO TRENDS LATELY WHERE FORECASTS HAVE BEEN TOO
WARM.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
NORTHERN U.S. 12Z SAT. THIS TROUGH REMAINS OVER THE AREA ON SUN. A
TROUGH DIGS IN THE NORTHERN PLAINS ON MON AND AFFECTS THE UPPER
GREAT LAKES MON NIGHT INTO TUE. TEMPERATURES CONTINUE TO LOOK COLDER
THAN NORMAL THROUGH THE PERIOD WITH NO WARM UP IN SIGHT. WITH COLD
TEMPERATURES IN PLACE...LAKE EFFECT SNOW WILL BE POSSIBLE THIS
EXTENDED PERIOD FOR SAT AND SUNDAY. ANOTHER SYSTEM ARRIVES FOR MON
INTO TUE AND BRINGS A CHANCE FOR SNOW. THIS SYSTEM WILL HAVE TO BE
WATCHED AS COULD BE ANOTHER SIGNIFICANT WINTER STORM AND WILL HIT UP
THIS POTENTIAL IN THE HWO PRODUCT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 649 AM EDT WED MAR 13 2013
SYSTEM THAT HAS BROUGHT THE SNOW TO THE AREA OVER THE LAST COUPLE
OF DAYS AS STARTED TO EXIT AND DRIER AIR HAS SURGED SOUTH ACROSS
LAKE SUPERIOR. THIS SHOULD LEAD TO VFR CONDITIONS FOR MUCH OF THE
FORECAST PERIOD. THERE ARE A COUPLE ITEMS TO NOTE THOUGH.
FIRST...THERE WILL STILL BE GUSTY WINDS THROUGH THE EARLY
AFTERNOON...ESPECIALLY AT KSAW. THIS COULD PRODUCE A SOME BLOWING
SNOW...BUT LEFT VISIBILITY RESTRICTIONS OUT OF THE TAF.
SECOND...MODELS ARE SHOWING A POCKET OF LOWER LEVEL MOISTURE MOVING
SOUTHEAST ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND INTO THE
EVENING HOURS. CONFIDENCE IS LIMITED ON THIS OCCURRING WITH THE
LACK OF CLOUDS UPSTREAM...BUT DID PUT A MENTION OF BORDERLINE MVFR
CEILINGS FOR KCMX/KSAW. FINALLY...A SHORTWAVE WILL BE MOVING
THROUGH WISCONSIN TOMORROW...WHICH WILL SPREAD MID CLOUDS OVER THE
AREA AND COULD BRUSH KIWD WITH -SHSN AT THE END OR JUST AFTER THE
TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EDT WED MAR 13 2013
A SURFACE TROUGH THAT DROPPED SOUTH ACROSS LAKE SUPERIOR LAST NIGHT
WILL CONTINUE TO PRODUCE NORTHWEST WINDS OF 20-30KTS OVER THE
EASTERN LAKE TODAY. BUT WITH THE PARENT LOW MOVING NORTHEAST THROUGH
QUEBEC...THIS TIGHT PRESSURE GRADIENT WILL WEAKEN THIS AFTERNOON AS
HIGH PRESSURE MOVES OVER THE LAKE TONIGHT. WINDS HAVE DROPPED
BELOW GALES AT OBSERVATION SITES AND HAVE DROPPED THE GALE WARNING.
THERE COULD STILL BE A FEW GALE FORCE GUSTS OVER THE EASTERN LAKE
DURING THE MORNING...BUT THE COVERAGE SHOULD BE LIMITED. TONIGHT/S
HIGH WILL BEGIN TO SHIFT EAST ON THURSDAY...ALLOWING A COLD FRONT TO
DROP SOUTHEAST ACROSS LAKE SUPERIOR ON THURSDAY NIGHT. A SECONDARY
LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST FROM THE UPPER MISSISSIPPI
VALLEY TO THE LOWER GREAT LAKES ON FRIDAY INTO FRIDAY
NIGHT...SHIFTING WINDS TO A NORTHERLY DIRECTION AT 15-30KTS. BEHIND
THIS LOW...A LARGE AREA OF HIGH PRESSURE WILL MOVE INTO THE UPPER
GREAT LAKES FOR SATURDAY. ANOTHER WEAK TROUGH WILL MOVE ACROSS LAKE
SUPERIOR ON SATURDAY NIGHT BEFORE THE HIGH PRESSURE RIDGE RESETS
OVER THE UPPER GREAT LAKES.
THERE WILL BE FREEZING SPRAY OVER CENTRAL AND EASTERN LAKE SUPERIOR
THROUGH THIS EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TOPEKA KS
555 PM CDT WED MAR 13 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
MODELS SHOW LITTLE IN THE WAY OF FORCING OR DEEP MOISTURE. THEREFORE
A VFR FORECAST IS EXPECTED TO PERSISTS WITH A WEAK SFC TROUGH MOVING
ACROSS THE AREA THROUGH THE DAY THURSDAY. THE RAP AND NAM SHOW THE
LOW LEVEL JET INCREASING TO AROUND 40KTS OVERNIGHT SO CONTINUED WITH
LLWS.
WOLTERS
&&
.PREV DISCUSSION... /314 PM CDT WED MAR 13 2013/
TONIGHT THROUGH TOMORROW...VERY LITTLE SENSIBLE WEATHER ON TAP FOR
THE SHORT TERM PORTION OF THE FORECAST. ONCE BAND OF MID CLOUDS MOVE
SOUTHEAST EXPECT MOSTLY CLEAR SKIES OVERNIGHT. HIGH PRESSURE CENTER
WILL MOVE EAST AND WINDS WILL STRENGTHEN FROM THE SOUTH ...USHERING
IN WARMER TEMPERATURES. WEAK BOUNDARY DOES MOVE THROUGH TOMORROW BY
MIDDAY...WHICH ONLY SERVES TO SWITCH WINDS TO THE WEST AND CONTINUE
WARMING TREND.
HARDING
THURSDAY NIGHT THROUGH WEDNESDAY...A NORTHWESTERLY ZONAL FLOW WILL
BE IN PLACE ACROSS THE CONUS BY THE END OF THE WORK WEEK WITH A
SOUTHWESTERLY SURFACE FLOW AS AN AREA OF LOW PRESSURE OVER THE
NORTHERN PLAINS SINKS SOUTHWARD INTO THE CENTRAL PLAINS. WITH A MILD
DAY EXPECTED ON THURSDAY...LOWS THURSDAY NIGHT WILL ONLY DROP INTO
THE UPPER 30S/LOWER 40S DESPITE MOSTLY CLEAR SKIES. AS A
RESULT...CAN EXPECT A MILD START TO THE DAY ON FRIDAY...WITH MODELS
SHOWING 850MB TEMPERATURES SOARING UPWARDS OF 14C-16C DEGREES BY THE
AFTERNOON HOURS. WITH THE SOUTHWESTERLY SURFACE FLOW INCREASING
THROUGH THE DAY...COULD SEE AFTERNOON HIGHS TOPPING OUT IN THE
LOW/MID 70S ACROSS FAR NORTHERN AND NORTHEAST KANSAS AND INTO THE
MID/UPPER 70S ACROSS CENTRAL AND EAST CENTRAL KANSAS. MODELS SHOW
THE SURFACE LOW TRACKING EASTWARD ACROSS THE FORECAST AREA BY FRIDAY
AFTERNOON...WITH A COLD FRONT MOVING THROUGH THE CWA FRIDAY NIGHT
AND IT LOOKS TO BE SOUTH OF THE AREA AFTER MIDNIGHT.
SATURDAY AND SUNDAY...SURFACE HIGH PRESSURE WILL SPREAD SOUTHWARD
ACROSS THE NORTHERN AND CENTRAL PLAINS BEHIND THE FRONT WITH
TEMPERATURES EXPECTED TO DROP BACK DOWN TO JUST BELOW THE SEASONAL
NORMALS AS SURFACE WINDS SHIFT TO THE NORTHEAST. MODELS CONTINUE TO
SHOW A FEW WEAK WAVES DEVELOPING WITHIN THE ZONAL FLOW DURING THE
SATURDAY TO SUNDAY TIMEFRAME. THERE IS STILL UNCERTAINTY
AMONGST THE MODELS REGARDING THE EXACT TRACKING OF THESE WAVES AND
THE BEST TIMING OF ANY LIGHT PRECIPITATION...BUT PRECIPITATION
CHANCES CURRENTLY LOOK TO INCREASE BY SATURDAY NIGHT AS A BIT MORE
MOISTURE MOVES INTO THE AREA. WITH TEMPERATURES DROPPING TO
AROUND THE FREEZING MARK EARLY SUNDAY MORNING OVER NORTHERN AND
NORTHEAST KANSAS...COULD SEE A BRIEF PERIOD OF A RAIN/SNOW MIX. HIGH
TEMPERATURES SATURDAY AND SUNDAY ARE EXPECTED TO BE IN THE UPPER 40S
TO LOWER 50S.
SUNDAY NIGHT THROUGH MONDAY...A MORE WELL-DEFINED SHORTWAVE TROUGH
WILL DEVELOP ACROSS THE NORTHERN PLAINS SUNDAY NIGHT AND PROGRESS
EASTWARD TOWARD THE GREAT LAKES REGION ON MONDAY. SURFACE LOW
PRESSURE ASSOCIATED WITH THIS WAVE WILL DRAG A COLD FRONT EASTWARD
THROUGH THE FORECAST AREA LATE SUNDAY NIGHT INTO MONDAY
MORNING...BRINGING A BETTER CHANCE FOR PRECIPITATION BEFORE EXITING
EAST OF THE AREA BY MONDAY AFTERNOON. ONCE AGAIN...LOW TEMPERATURES
EARLY MONDAY MORNING COULD BE NEAR THE FREEZING MARK ACROSS NORTHERN
AND NORTHEAST KANSAS SO THERE MAY BE A BIT OF A RAIN/SNOW MIX BEFORE
TRANSITIONING BACK OVER TO RAIN.
TUESDAY AND WEDNESDAY...ONCE THIS WAVE PASSES TO THE
EAST...NORTHWESTERLY ZONAL FLOW WILL RETURN TO THE CENTRAL CONUS
WITH DRY CONDITIONS EXPECTED AS SURFACE HIGH PRESSURE BUILDS INTO
THE NORTHERN AND CENTRAL PLAINS. TEMPERATURES LOOK TO BE BACK ON THE
RISE BY WEDNESDAY WITH A RETURN OF ABOVE-NORMAL TEMPERATURES.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
423 PM EDT WED MAR 13 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF/
CLOSED UPR LO CENTERED JUST S OF JAMES BAY MOVING STEADILY TO THE
E...ALLOWING A RDG OVER THE ROCKIES TO EXPAND TO THE E...WITH
00Z-12Z H3 HGT RISES UP TO 150M EVIDENT OVER THE NRN PLAINS/UPR MS
RIVER VALLEY. ALTHOUGH A STEADY NNW FLOW BTWN ASSOCIATED SFC LO OVER
SE CANADA AND HI PRES RDG AXIS STRETCHING FM NW ONTARIO INTO THE
CENTRAL PLAINS IS PUSHING H85 TEMPS AS LO AS -13C TO -15C INTO THE
UPR LKS...THE AIRMASS IMMEDIATELY UPSTREAM IS SO DRY PER 12Z INL
RAOB THAT THERE ARE NO -SHSN OR EVEN MUCH IN THE WAY OF LK CLDS OVER
UPR MI ATTM. LOOKING A BIT FARTHER TO THE NW...THERE WAS SOME SC
NOTED EARLIER OVER PORTIONS OF NW ONTARIO ASSOCIATED WITH A BIT MORE
MSTR SHOWN ON THE 12Z YPL RAOB...BUT SUBSIDENCE ASSOCIATED WITH THE
APRCHG H3 HGT RISES/SFC ACYC FLOW AS WELL AS SOME DAYTIME HEATING
HAS CAUSED THIS CLD TO DISSIPATE. FARTHER TO THE NW...A SHRTWV
MOVING THRU ALBERTA AND INTO SASKATCHEWAN IS ROUNDING THE UPR RDG
OVER THE ROCKIES. MID/HI CLDS AHEAD OF THIS DISTURBANCE AND
ASSOCIATED WARM FNT OVER THE HI PLAINS ARE PUSHING E THRU THE
DAKOTAS/SCENTRAL CANADA THIS AFTN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/IMPACT ON TEMPS.
TNGT...ALTHOUGH LK CLDS HAVE DISSIPATED WITH ARRIVAL OF DRIER AIR/
DAYTIME HEATING WITH HIER MARCH SUN ANGLE THAT TENDS TO CAUSE
SUBSIDENCE OVER LK SUP...CONCERNED SOME CLDS WL REFORM THIS EVNG
WITH LOSS OF HEATING/ARRIVAL OF MSTR NOTED IN NW ONTARIO IN THE
PRESENCE OF H85 TEMPS NEAR -12C AND THEN SPREAD INLAND INTO MAINLY
THE NCENTRL AND ERN CWA IN NW FLOW AHEAD OF APRCHG HI PRES RDG AXIS.
BUT AS THE HI PRES RDG AXIS APRCHS FM THE W...INCRSG SUBSIDENCE/MORE
ACYC LLVL FLOW IS FCST TO SINK THE SUBSIDENCE INVRN LO ENUF ANY LO
CLD SHOULD DSPT W-E. ALTHOUGH FCST H85 TEMPS ARE MARGINAL FOR LES...
LO INVRN BASE 2-3K FT AGL WL LIMIT LES TO PERHAPS SOME FLURRIES OVER
THE ERN ZNS DOWNWIND OF THE LK IN LLVL NW FLOW. PREVIOUS FCST HAD A
REASONABLE HANDLE ON THESE EXPECTATIONS...SO MADE FEW CHANGES TO
THESE GRIDS. SOME MID/HI CLDS WELL IN ADVANCE OF APRCHG SHRTWV/WARM
FNT TO THE W ARE FCST TO MOVE INTO THE WRN ZNS LATE TNGT. BUT WITH A
PERIOD OF MAINLY CLR SKIES/LGT WINDS...WL MAINTAIN MIN TEMPS FCST
NEAR LO END OF GUIDANCE OVER MUCH OF THE INTERIOR W HALF.
THU...SHRTWV NOW MOVING THRU SCENTRAL CANADA OVER TOP OF ROCKIES RDG
IS FCST TO MOVE THRU NW ONTARIO. ALTHOUGH CLD WL OVERSPREAD UPR MI
W-E AHEAD OF THE WARM FNT...PASSAGE OF SHARPER DPVA/DEEP LYR QVECTOR
CNVGC TO THE N CLOSER TO TRACK OF DISTURBANCE AS WELL AS LIMITED
DEPTH OF ABSOLUTE MSTR RETURN SHOULD RESULT IN A DRY DAY. H85 TEMPS
ARE FCST TO RISE TO BTWN ABOUT -2C OVER THE W AND -8C OVER THE E BY
00Z FRI AS A SW FLOW DVLPS ON THE WRN FLANK OF RETREATING HI PRES...
SO EXPECT A WARMER DAY ESPECIALLY OVER THE W HALF.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
UPPER LEVEL PATTERN STARTS OFF LONG TERM WITH ELONGATED TROUGH OVER
MOST OF NORTHERN AND EASTERN CANADA AND RIDGING OVER WESTERN CANADA.
OVER TIME RIDGE IS FLATTENED AS TROUGHING OVR CANADA SETTLES INTO
NORTHERN TIER OF CONUS THROUGH THE UPCOMING WEEKEND. ZONAL WNW FLOW
RESULTS AND WILL BRING STRONGER SHORTWAVE ACROSS NORTHERN PLAINS AND
UPPER GREAT LAKES THURSDAY NIGHT AND FRIDAY. TRICKY SYSTEM WITH
REGARD TO NORTHERN EXTENT OF HEAVIER SNOW. AS ALLUDED TO YDY...WILL
GREATLY DEPEND ON HOW FAR SOUTH SFC-H85 BAROCLINIC ZONE ALLIGNS IN
WAKE OF NORTHERN STREAM SHORTWAVE MOVING THROUGH THURSDAY NIGHT. GFS
AND GEM-NH FARTHER SOUTH /12Z GFS TRENDED EVEN FARTHER SOUTH/ WHILE
NAM IS MUCH FARTHER NORTH. ECMWF/UKMET A COMPROMISE...BUT THE ECMWF
DID TREND FARTHER SOUTH COMPARED TO THE 12Z RUN FROM YDY/12 MARCH.
SEEMS LIKE THE NAM IS BECOMING MORE OF A NORTHERN OUTLIER...SO WILL
TEND TO TREND AWAY FROM THAT IDEA AND ANY MODELS THAT ARE
INITIALIZED OFF OF IT SUCH AS OUR LOCAL WRF. STILL THINK THAT THE
LOCATION OF TIGHTER LOW-LEVEL TEMPERATURE GRADIENT WILL BE
ULTIMATELY WHERE HEAVIEST QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE
AND SFC-H85 LOWS MOVE IN FROM NORTHERN PLAINS.
WHERE THE TIGHT THERMAL GRADIENT OCCURS THERE IS A POTENTIAL FOR A
NARROW STRIPE OF HEAVY SNOW DUE TO LOW-MID LEVEL FRONTOGENESIS AMD
DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK DROPPING
INTO GREAT LAKES FROM ONTARIO ALONG WITH DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS 3-4G/KG. SFC-H85 LOWS/LOW-LEVEL FLOW IS
SHOWING A STRENGTHENING TREND OVERALL AS WELL. BASED ON MODEL
CONSENSUS...SEEMS LIKE BETTER CHANCE FOR ENHANCEMENT/HEAVIER SNOW TO
COME TOGETHER MAY END UP JUST TO OUR SOUTH. WILL KEEP POPS LIKELY
TOWARD THE WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER THAT
SNOW OCCURS. MAY NEED HEADLINES...LIKELY ADVISORIES...IN THESE AREAS
FRIDAY INTO FRIDAY EVENING. WWD DAY2 GRAPHICS INDICATE SWATH OF 2-4
INCHES OF SNOW FRIDAY ALONG WI BORDER...WITH JUST A COUPLE INCHES
OVER NORTHERN UPR MICHIGAN. BASED ON CROSS SECTIONS FROM GFS AND
JUST THE LOOK FROM QPF FIELDS...COULD BE A VERY SHARP CUTOFF TO SNOW
ON NORTH SIDE. AS AGEOSTROPIC CIRCULATION WITHIN H85-H7 FRONTOGENEIS
OCCURS THERE ARE INDICATIONS THAT SUBSIDENCE AREA OVER NORTHERN UPR
MICHIGAN WILL DRAW INCREASINGLY DRIER AIR IN FROM CANADA. GRADIENT
OF SNOW AMOUNTS MAY END UP SIMILAR TO SNOW EVENT FROM LATE MARCH OF
2011 THAT IMPACTED FAR SOUTH CENTRAL CWA WITH OVER A FOOT OF SNOW
WHILE NORTHERN CWA ONLY SAW FLURRIES. WE SHALL SEE. ONCE SNOW TAPERS
OFF...DESPITE SUFFICIENT COLD AIR IN LOW-LEVELS...UNSURE ON EXTENT
OF LK EFFECT GIVEN CONCERNS WITH THE DRY AIR.
FAIRLY QUIET LATER FRIDAY NIGHT INTO SATURDAY MORNING. MAY SEE SOME
SNOW SHOWERS FLARE UP SATURDAY AFTN INTO SATURDAY NIGHT WITH ARRIVAL
OF SHORTWAVE/COLD AIR ADVECTION DRIVING H85 TEMPS DOWN TO NEAR -20C.
MODELS HINT AT SHARPER LOW-LEVEL TROUGH MOVING THROUGH SATURDAY
EVENING WHICH MAY ALSO ENHANCE THE SNOW. INCREASED POPS A BIT INTO
SATURDAY NIGHT. GIVEN FAVORABLE LOCATION OF DGZ WITHIN MOIST LAYER
PRESENT WITH LAKE EQLS UP TO 10KFT...MAY SEE SEVERAL INCHES OF
FLUFFY SNOW ALONG LK SUPERIOR. INVERSION LOWERS BLO 5KFT THROUGH
DAY ON SUNDAY...BUT ENOUGH COLD AIR LINGERS FOR NW FLOW AREAS TO SEE
SCT LK EFFECT SNOW SHOWERS.
ATTN THEN TURNS TO SHORTWAVE TROUGHING DIGGING ACROSS ROCKIES BY
SUNDAY HELPING TO DEEPEN SFC LOW ON THE LEE SIDE OF THE ROCKIES.
UPPER TROUGH/SFC LOW IS FORECAST TO HEAD EAST AND DEEPEN AS
SHORTWAVE IN THE NORTHERN BRANCH ATTEMPTS TO PHASE WITH THE SOUTHERN
STREAM SYSTEM. SFC LOW DEEPENS FURTHER AND LIFTS ACROSS GREAT LAKES
WHICH MAY LEAD TO A SIGNIFICANT SNOW STORM OVER PORTIONS OF THE
UPPER GREAT LAKES. UP TO 12Z THERE WAS ACTUALLY GOOD AGREEMENT FROM
THE ECMWF AND GFS ON TRACK OF THE LOW. 12Z ECMWF JOGGED FARTHER WEST
THOUGH IT WOULD STILL BE MAINLY A SNOW EVENT. WAVES PRODUCING THIS
WEATHER SYSTEM ARE STILL WELL TO THE NORTH...UNDERSTATEMENT...OVER
THE NORTHWEST TERRITORIES OF CANADA...AND IN THE VCNTY OF THE NORTH
POLE. THERE IS A LOT OF INTERACTION THAT HAS TO OCCUR YET BTWN THESE
WAVES...AND LIKELY OTHERS AS WELL...BEFORE A FINAL SOLUTION IS
DETERMINED. CERTAINLY A SYSTEM TO WATCH THOUGH AS IT WILL HAVE GULF
MOISTURE TO WORK ON. CONVECTION TO THE SOUTH TOO SO THAT INTERACTION
WILL NEED TO BE ADDRESSED BY MODELS AS WELL. MID SHIFT PUT A MENTION
IN HWO...WHICH SEEMS LIKE GOOD CALL IN THIS SITUATION. STRONGER
SYSTEM DRAWS DOWN CONTINUAL COLD AIR ACROSS LK SUPERIOR THROUGH
MIDWEEK SO PUT CHANCE POPS IN OVER NORTHERN CWA. LAST PANELS OF GFS
AND ECMWF INDICATE SOME POTENTIAL FOR MODERATING TEMPS TOWARD LAST
WEEK OF MARCH AS MEAN TROUGH ATTEMPTS TO SHIFT INTO EASTERN CANADA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 126 PM EDT WED MAR 13 2013
EXPECT PREDOMINANT VFR CONDITIONS AND SLOWLY DIMINISHING WINDS THIS
AFTN AS HI PRES RDG AXIS/AREA OF DRIER LLVL AIR MOVES SLOWLY EWD AND
PRES GRADIENT WEAKENS. NEXT CONCERN IS IMPACT OF AREA OF LLVL MSTR
THAT IS PRESENT OVER NW ONTARIO. NUMERICAL GUIDANCE SHOWS THIS MOIST
AIR STREAMING SEWD ACRS LK SUP AND INTO MAINLY NCENTRAL AND ERN UPR
MI IN THE NW FLOW AHEAD OF THE ENCROACHING HI. CONCERNED THERE COULD
BE SOME LK CLDS THAT FORM WITHIN THE CHILLY AIRMASS AFTER SUNSET
ESPECIALLY AT CMX/SAW...SO RETAINED FCST OF HI END MVFR CIGS BTWN
00Z-06Z AT CMX/SAW. AS THE HI PRES RDG MOVES CLOSER...EXPECT
SUBSIDENCE INVRN TO LOWER ENUF LATE TNGT TO DISSIPATE ANY MVFR CLDS
THAT DO FORM. ALTHOUGH SOME MID/HI CLDS WL INVADE THE AREA ON THU...
PREVAILING DRY LLVL AIR WL RESULT IN VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT WED MAR 13 2013
AS HI PRES RIDGE AXIS MOVES IN FROM THE W TONIGHT...THE PRES
GRADIENT WILL WEAKEN OVER LAKE SUP...CAUSING NNW WINDS UP TO 30 KTS
LATE THIS AFTERNOON OVER THE E HALF TO DIMINISH AND FREEZING SPRAY
TO END. WINDS WILL SHIFT TO THE SW ON THU AS THE RIDGE AXIS MOVES TO
THE E...BUT WINDS WILL BE UNDER 20 KTS UNTIL LATE IN THE DAY OVER
THE W AS ANOTHER TROF APPROACHES FROM THE NW AND SHARPENS THE PRES
GRADIENT.
DUE TO THAT TIGHTER PRESSURE GRADIENT...W WINDS TO 25 KTS INCREASE TO
30 KTS WHILE SHIFTING N-NW ON THU NIGHT. SLIGHT RISK THAT GALE GUSTS
COULD OCCUR RIGHT IN WAKE OF THE WIND SHIFT THURSDAY EVENING OVER
EASTERN LK SUPERIOR. EXPECT N-NE WINDS TO 25 KTS THROUGH FRI AS LOW
PRESSURE PASSES SOUTH OF THE REGION. AFTER LIGHTER WINDS INTO SAT
MORNING ANOTHER TROUGH WILL SHIFT WINDS TO NW TO 25 KTS SAT NIGHT.
WINDS DIMINISH ON SUN BUT INCREASE YET AGAIN LATE ON MON AS STRONG
LOW PRESSURE SYSTEM LIFTS ACROSS THE UPR LAKES REGION. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
127 PM EDT WED MAR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EDT WED MAR 13 2013
WV IMAGERY AND RUC ANALYSIS UPPER TROUGH IS STILL ROTATING OVER THE
GREAT LAKES REGION THIS MORNING. THE ABUNDANT MOISTURE WITH THIS
UPPER LOW AND 850MB TEMPERATURES AROUND -16C LED TO MODERATE TO
HEAVY LAKE EFFECT SNOW OFF LAKE SUPERIOR YESTERDAY INTO THE
OVERNIGHT HOURS. AS OF 2AM...THE SNOWFALL TOTAL AT OUR OFFICE HAD
REACHED 8.7 INCHES. BUT MID LEVEL DRYING...SEEN ON THE 00Z KINL AND
CWPL SOUNDINGS ALONG WITH IR SATELLITE OVER WESTERN LAKE
SUPERIOR...HAD BROUGHT A QUICK END TO THE SNOW OVER THE WESTERN CWA
SHORTLY AFTER MIDNIGHT AND RECENT RADAR TRENDS OVER THE CENTRAL AND
EAST SHOW SIMILAR QUICK DECREASE.
UPPER RIDGE AND SURFACE HIGH PRESSURE WILL BE BUILDING IN TODAY AND
REMAINING INTO TONIGHT. THIS WILL CONTINUE TO PULL THE DRY AIR OVER
THE AREA AND SHOULD BRING AN END TO THE LINGERING SNOW SHOWERS OVER
THE EAST DURING THE MORNING HOURS. WITH THE QUICK DECREASE TO THE
SNOW...DECIDED TO DROP THE REMAINING WINTER WX ADVISORIES OVER THE
EAST. THE GUSTY WINDS TODAY WILL KEEP SOME BLOWING SNOW IN THE
FORECAST...WITH THE BEST CHANCES NEAR LAKE SUPERIOR EAST OF
MARQUETTE.
BASED ON LATEST TRENDS...HAVE OPTED TO GO MORE A LITTLE MORE
OPTIMISTIC ON THE CLOUD COVER FOR TODAY. THE QUICK TRANSITION TO
VFR AND MID CLOUDS OVER THE WEST SHOWS A LACK OF LOW LEVEL MOISTURE
EVENTHOUGH 850MB TEMPS ARE STILL AROUND -14C. THERE IS JUST ENOUGH
TERRAIN ENHANCEMENT TO AID CLOUD COVER OVER THE WEST AND THAT COULD
BE THE CASE TODAY...ESPECIALLY WITH SOME DIURNAL HEATING HELP.
THUS...AFTER THE DEEPER MOISTURE DEPARTS THIS
MORNING...TRANSITIONED TO A PARTLY CLOUDY SKY WITH THE GREATEST
CLEARING NEAR THE WISCONSIN BORDER. HIGHS TODAY WILL REMAIN BELOW
NORMAL WITH MOST LOCATIONS IN THE MID-UPPER 20S.
FOR TONIGHT...MODELS STILL HINTING AT A INCREASE IN THE MOISTURE IN
THE 925-875MB RANGE LATE THIS AFTERNOON INTO THIS EVENING FROM THE
KEWEENAW SOUTHEAST THROUGH MARQUETTE/ALGER COUNTIES. 875MB TEMPS
AROUND -12.5C WOULD SUPPORT ENOUGH INSTABILITY FOR SOME SNOW
SHOWERS...BUT CONCERN IS THE DEPTH OF THE CLOUD LAYER WHICH WILL
LIKELY ONLY BE 2-3KFT. THERE WAS A THIN AREA OF CLOUDS THIS PAST
EVENING WHERE THE MODELS ARE SHOWING THE LOW MOISTURE...BUT IT HAS
SINCE DISSIPATED. THAT MOISTURE MAY STILL BE PRESENT AND WITH THE
INFLUENCE OF LAKE SUPERIOR...PUT IN A MENTION OF ISOLATED
FLURRIES FOR ALGER/LUCE/SCHOOLCRAFT COUNTIES.
OTHERWISE...HIGH PRESSURE SHOULD BE IN PLACE OVER THE AREA AND LEAD
TO A QUIET NIGHT. THE WESTERN CWA WILL LIKELY BE MOSTLY CLEAR
DURING THE EVENING HOURS BEFORE MID/HIGH CLOUDS START STREAMING IN
AHEAD OF THE NEXT SHORTWAVE DROPPING THROUGH THE NORTHWEST FLOW
ALOFT. THINKING THE HIGH CLOUDS WILL BE IN BY MIDNIGHT AND THEN
THEY WILL THICKEN/LOWER THROUGH THE NIGHT AND COVER ALL OF THE
WESTERN CWA BY MORNING. THIS GIVES CONCERN TO LOWS FOR TONIGHT...AS
THE CLOUD COVER WILL HAVE A GREAT INFLUENCE ON TEMPERATURES WITH THE
OTHERWISE GOOD RADIATIONALLY COOLING NIGHT WITH LIGHT WINDS AND
PWATS AROUND 50 PERCENT OF NORMAL. THE REGIONAL GEM...WHICH USUALLY
DOES WELL IN THESE RADIATIONAL AND CLOUD SITUATIONS HAS LOWS AROUND
ZERO AROUND IRON COUNTY AND THAT COMBINED WITH THE PREVIOUS FORECAST
SEEMS LIKE THE WAY TO GO. UNFORTUNATELY IN THESE SITUATIONS...AN
HOUR OR TWO DIFFERENCE IN CLOUD COVER TIMING CAN EASILY BUST THE
FORECAST IN EITHER DIRECTION.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 447 AM EDT WED MAR 13 2013
UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S.
WITH A TROUGH OVER THE EASTERN U.S. 12Z THU. THE RIDGE GETS
FLATTENED WITH TIME ON FRI WITH A SHORTWAVE MOVING INTO THE NORTHERN
PLAINS LATE FRI. NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE
AND DEEPER MOISTURE MOVING IN ON FRI AND FRI NIGHT.
FOR THIS FORECAST...NOT REAL CONFIDENT IN THE STORM SYSTEM FOR
FRIDAY FOR NOW. ECMWF AND GFS ARE TAKING THE SYSTEM A BIT FURTHER
SOUTH WHILE THE NAM IS NORTH WITH IT. NO REAL CONTINUITY IN THE
MODELS EITHER WITH THEIR FORECASTS...SO CONFIDENCE IS FAIRLY LOW.
WITH THE DIFFERENCE IN PLACEMENT OF THE SYSTEM...THIS WILL AFFECT
HOW COLD 850 MB TEMPERATURES ARE. 12Z ECMWF WAS MUCH WARMER AT 850
MB WITH TEMPERATURES OF -4C TO -8C ON FRI. 00Z ECMWF NOW IS COLDER
WITH 850 MB TEMPERATURES -8C TO -14C WHILE THE GFS IS -10C TO -12C.
WITH NORTH WINDS AND DELTA-T GREATER THAN 11C...THIS IS ENOUGH FOR
LAKE ENHANCEMENT OF THE SNOW. COULD SEE UP TO 5 INCHES OF SNOW ON
FRIDAY INTO FRIDAY NIGHT AND WILL PROBABLY NEED SOME HEADLINES UP
FOR FRIDAY AND FRIDAY NIGHT. WENT LIKELY POPS ON FRIDAY FOR THE LAKE
ENHANCEMENT. FOR THU...LOOKS LIKE A SYSTEM WILL STAY TO THE WEST OF
THE AREA AND ENDED UP GOING DRIER FOR THE FORECAST AS 850 MB
TEMPERATURES ARE NOT COLD ENOUGH FOR LAKE ENHANCEMENT.
OVERALL...LOWERED HIGH TEMPERATURES A COUPLE DEGREES ALONG WITH
OVERNIGHT LOWS DUE TO TRENDS LATELY WHERE FORECASTS HAVE BEEN TOO
WARM.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
NORTHERN U.S. 12Z SAT. THIS TROUGH REMAINS OVER THE AREA ON SUN. A
TROUGH DIGS IN THE NORTHERN PLAINS ON MON AND AFFECTS THE UPPER
GREAT LAKES MON NIGHT INTO TUE. TEMPERATURES CONTINUE TO LOOK COLDER
THAN NORMAL THROUGH THE PERIOD WITH NO WARM UP IN SIGHT. WITH COLD
TEMPERATURES IN PLACE...LAKE EFFECT SNOW WILL BE POSSIBLE THIS
EXTENDED PERIOD FOR SAT AND SUNDAY. ANOTHER SYSTEM ARRIVES FOR MON
INTO TUE AND BRINGS A CHANCE FOR SNOW. THIS SYSTEM WILL HAVE TO BE
WATCHED AS COULD BE ANOTHER SIGNIFICANT WINTER STORM AND WILL HIT UP
THIS POTENTIAL IN THE HWO PRODUCT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 126 PM EDT WED MAR 13 2013
EXPECT PREDOMINANT VFR CONDITIONS AND SLOWLY DIMINISHING WINDS THIS
AFTN AS HI PRES RDG AXIS/AREA OF DRIER LLVL AIR MOVES SLOWLY EWD AND
PRES GRADIENT WEAKENS. NEXT CONCERN IS IMPACT OF AREA OF LLVL MSTR
THAT IS PRESENT OVER NW ONTARIO. NUMERICAL GUIDANCE SHOWS THIS MOIST
AIR STREAMING SEWD ACRS LK SUP AND INTO MAINLY NCENTRAL AND ERN UPR
MI IN THE NW FLOW AHEAD OF THE ENCROACHING HI. CONCERNED THERE COULD
BE SOME LK CLDS THAT FORM WITHIN THE CHILLY AIRMASS AFTER SUNSET
ESPECIALLY AT CMX/SAW...SO RETAINED FCST OF HI END MVFR CIGS BTWN
00Z-06Z AT CMX/SAW. AS THE HI PRES RDG MOVES CLOSER...EXPECT
SUBSIDENCE INVRN TO LOWER ENUF LATE TNGT TO DISSIPATE ANY MVFR CLDS
THAT DO FORM. ALTHOUGH SOME MID/HI CLDS WL INVADE THE AREA ON THU...
PREVAILING DRY LLVL AIR WL RESULT IN VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EDT WED MAR 13 2013
A SURFACE TROUGH THAT DROPPED SOUTH ACROSS LAKE SUPERIOR LAST NIGHT
WILL CONTINUE TO PRODUCE NORTHWEST WINDS OF 20-30KTS OVER THE
EASTERN LAKE TODAY. BUT WITH THE PARENT LOW MOVING NORTHEAST THROUGH
QUEBEC...THIS TIGHT PRESSURE GRADIENT WILL WEAKEN THIS AFTERNOON AS
HIGH PRESSURE MOVES OVER THE LAKE TONIGHT. WINDS HAVE DROPPED
BELOW GALES AT OBSERVATION SITES AND HAVE DROPPED THE GALE WARNING.
THERE COULD STILL BE A FEW GALE FORCE GUSTS OVER THE EASTERN LAKE
DURING THE MORNING...BUT THE COVERAGE SHOULD BE LIMITED. TONIGHT/S
HIGH WILL BEGIN TO SHIFT EAST ON THURSDAY...ALLOWING A COLD FRONT TO
DROP SOUTHEAST ACROSS LAKE SUPERIOR ON THURSDAY NIGHT. A SECONDARY
LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST FROM THE UPPER MISSISSIPPI
VALLEY TO THE LOWER GREAT LAKES ON FRIDAY INTO FRIDAY
NIGHT...SHIFTING WINDS TO A NORTHERLY DIRECTION AT 15-30KTS. BEHIND
THIS LOW...A LARGE AREA OF HIGH PRESSURE WILL MOVE INTO THE UPPER
GREAT LAKES FOR SATURDAY. ANOTHER WEAK TROUGH WILL MOVE ACROSS LAKE
SUPERIOR ON SATURDAY NIGHT BEFORE THE HIGH PRESSURE RIDGE RESETS
OVER THE UPPER GREAT LAKES.
THERE WILL BE FREEZING SPRAY OVER CENTRAL AND EASTERN LAKE SUPERIOR
THROUGH THIS EVENING.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
345 PM EDT WED MAR 13 2013
.SYNOPSIS...
COLD NORTHWEST WINDS FLOWING OVER THE RELATIVELY WARM WATERS OF
LAKE ONTARIO WILL BRING SNOW SHOWERS TO THE AREA TONIGHT INTO
THURSDAY. A FEW INCHES OF SNOW COULD ACCUMULATE OVER OUR NORTHERN
COUNTIES... WITH LESS TO THE SOUTH. HIGH PRESSURE WILL BRING DRY
WEATHER THURSDAY NIGHT INTO FRIDAY... THEN THE NEXT STORM SYSTEM
APPROACHING FROM THE WEST WILL BRING A CHANCE OF LIGHT SNOW OR
MIXED PRECIPITATION BY LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY/...
SNOW SHOWERS ASSOCIATED WITH A POOL OF COLD AIR ALOFT WILL MOVE
ACROSS THE AREA LATE THIS AFTERNOON THROUGH MID-EVENING... WITH
SNOW SHOWERS DIMINISHING AFTER SUNSET. LATEST RAP SHORT-RANGE
FORECAST SOUNDINGS ARE STILL SHOWING SOME CAPE... GENERALLY 50 TO
150 J/KG ALONG WITH STEEP LOW-LEVEL LAPSE RATES. AS A RESULT SOME
REPORTS OF THUNDER HAVE BEEN RECEIVED FROM THE HEAVIEST SNOW
SHOWERS. WILL HAVE TO WATCH FOR SOME LOCALIZED AREAS OF SLICK
TRAVEL EARLY THIS EVENING AS ANY HEAVIER SQUALL COULD BRING A
QUICK COATING TO AN INCH OF SNOW ALONG WITH TEMPERATURES FALLING
TO NEAR OR JUST BELOW FREEZING.
SOME LAKE EFFECT SNOW BANDS WILL DEVELOP LATER THIS EVENING
THROUGH THE OVERNIGHT HOURS AS LOSS OF DIURNAL HEATING ALLOWS FOR
MORE ORGANIZATION OF THE RADAR ECHOES. LATEST GUIDANCE INDICATES
THAT 850 MB TEMPERATURES WILL FALL ALL THE WAY TO -20 C LATE
TONIGHT WHICH CERTAINLY WILL BE COLD ENOUGH FOR SOME LAKE EFFECT
GIVEN ADEQUATE SYNOPTIC-SCALE MOISTURE WHICH WILL ALSO BE IN
PLACE. FLOW WILL BE FROM AROUND 270 DEGREES LATE THIS EVENING
WHICH WILL FAVOR ANY ORGANIZED BAND TO BE NORTH OF SYRACUSE AND
THE THRUWAY. LATER TONIGHT THE FLOW SHIFTS TO BETWEEN 300 AND 310
DEGREES WHICH WILL FAVOR MULTIBANDS ACROSS A WIDE SECTION OF
CENTRAL NY. AT THIS POINT EXPECTING 2 OR 3 INCHES ACROSS MUCH OF
THE NORTHERN 1/3 OF THE FORECAST AREA BY THURSDAY MORNING.
&&
.SHORT TERM /6 AM THURSDAY THROUGH SATURDAY/...
SNOW SHOWERS WILL CONTINUE THURSDAY WITH A FLOW VECTOR FROM AROUND
300 DEGREES. ANOTHER COUPLE OF INCHES COULD FALL OVER THE NORTHERN
1/3 OF THE FORECAST AREA THROUGH LATE MORNING. DURING THE
AFTERNOON EXPECT SNOW SHOWERS TO BECOME DISORGANIZED WITH
INCREASING DIURNAL HEATING. 850 MB TEMPERATURES WILL RISE ONLY
SLIGHTLY DURING THE DAY AND ENOUGH SYNOPTIC SCALE MOISTURE WILL
REMAIN IN PLACE TO KEEP SOME SNOW SHOWERS GOING INTO THURSDAY
EVENING. TEMPERATURES WILL LIKELY REMAIN BELOW FREEZING ACROSS THE
ENTIRE AREA THROUGH THURSDAY DESPITE THE STRONG MARCH SUNSHINE.
A WEAK RIDGE OF HI PRESSURE WILL BRING A PERIOD OF DRY WEATHER
THURSDAY NIGHT INTO FRIDAY MORNING. LOW PRESSURE WILL TRACK ACROSS
SOUTHERN CANADA ON FRIDAY... DRAGGING A FRONTAL BOUNDARY SOUTH
ACROSS THE AREA DURING THE AFTERNOON. SOME MOISTURE STREAKING OUT
AHEAD OF AN APPROACHING CLIPPER SYSTEM MAY TRAIN ALONG THIS FRONT
FRIDAY AFTERNOON ALLOWING FOR SOME LIGHT SNOW OR A MIX OF LIGHT
RAIN AND SNOW TO BREAK OUT ACROSS THE AREA DURING THE DAY.
TEMPERATURES WILL RECOVER BACK ABOVE FREEZING FRIDAY AFTERNOON SO
THAT ANY SNOW THAT DOES FALL WILL LIKELY NOT ACCUMULATE MUCH.
CLIPPER SYSTEM PASSES SOUTH OF OUR AREA FRIDAY NIGHT INTO
SATURDAY. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE TRACK
AND INTENSITY OF THIS SYSTEM... AND AS OF NOW IT LOOKS LIKE THIS
SYSTEM WILL PRODUCE A PERIOD OF ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY MORNING ACROSS AT LEAST A PORTION OF THE AREA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A HIGHLY ACTIVE PATTERN WILL DOMINATE THE NORTHERN HEMISPHERE
DURING THIS PERIOD WITH A SERIES OF FRONTAL SYSTEMS AND LOW
PRESSURE SYSTEMS PASSING THROUGH...OR NEAR THE NORTHEASTERN
AND MID-ATLANTIC STATES.
THE INITIAL WAVE IN THE SERIES IS HANDLED DIFFERENTLY BY THE GFS
AND ECMWF MODEL TRENDS. THE 13/00Z EC WOULD BRING A PERIOD OF SNOW
THROUGH PA AND SOUTHERN NY DURING SUNDAY AFTERNOON AND EVENING
WHILE THE 13/12Z GFS REMAINS SUPPRESSED FURTHER SOUTH. THE 13/12Z
CANADIAN GGEM MODEL LEANS WITH A DRIER SOLUTION FOR THIS REGION.
AT THIS TIME IT IS PRUDENT TO MENTION A CHANCE OF PRECIP EXTENDING
ACROSS NEPA AND THE SOUTHERN HALF OF CNY.
A MORE SUBSTANTIAL SYSTEM IS GENERALLY AGREED UPON WITHIN THE
MODEL SOLUTIONS TO SLIDE THROUGH THE REGION LATER MONDAY INTO
TUESDAY AS AN OCCLUDED SYSTEM. THE GFS IS A LITTLE MORE WRAPPED UP
AND FURTHER N/W. THE SYSTEM GENERALLY LOOKS MILD WITH RAIN...ALTHOUGH
A MIX WITH SNOW IS STILL HIGHLY POSSIBLE. THIS SYSTEM WILL ALSO
USHER IN AN ANOMALOUSLY SHOT OF COLD AIR TO THE REGION FOR THE
LATTER HALF OF THE WEEK.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
18Z WED UPDATE...AN UNSTABLE ATMOSPHERE WITH A POTENT DISTURBANCE
MOVING THROUGH THE REGION HAS SPAWNED NUMEROUS BANDS OF SNOW
SHOWERS AND SQUALLS THIS AFTERNOON WHICH WILL CONTINUE INTO THE
EARLY EVENING. IN GENERAL...VFR/MVFR CIGS WILL PREVAIL BUT VSBYS
WILL BE HIGHLY VARIABLE IN AND OUT OF SQUALLS. MOST SNOW SHOWERS
WILL PRODUCE IFR VSBYS...BUT THE HEAVIEST SQUALLS COULD PRODUCE
NEAR WHITEOUT CONDITIONS FOR A SHORT AMOUNT OF TIME OVER THE
TERMINAL.
BEYOND ABOUT 00Z...SNOW SHOWERS WILL BECOME MORE SPORADIC AND
BECOME FOCUSED ALONG THE DOWNWIND TRAJECTORY OF LAKE ONTARIO
MAINLY AFFECTING KSYR-KRME WITH THE MOST RESTRICTIONS. ELSEWHERE...
DEEPENING COLD AIR WILL KEEP CIGS IN THE MVFR CATEGORY THROUGH
THURSDAY MORNING WITH SOME IMPROVEMENT TO VFR.
WINDS SW 10-15 KTS INTO THIS EVENING...BECOMING W-NW AND
INCREASING 15-25 KTS AND GUSTY LATER TONIGHT AND THURSDAY.
.OUTLOOK...
FRIDAY...MAINLY VFR BY AFTERNOON.
FRIDAY NIGHT/SATURDAY EVE...RESTRICTIONS POSSIBLE IN LIGHT SNOW.
SUNDAY...VFR.
MONDAY...BECOMING MVFR IN A RAIN/SNOW MIX.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1158 AM CDT WED MAR 13 2013
.DISCUSSION...LATEST SURFACE ANALYSIS SHOWS SURFACE LOW PRESSURE
IN SOUTHEAST ALBERTA WITH MAX PRESSURE FALLS IN EASTERN SASKATCHEWAN
SOUTH INTO NORTH CENTRAL NORTH DAKOTA. THE LOW WILL TRACK TOWARD
THE SOUTHEAST THROUGH THIS EVENING...TO NEAR BISMARCK BY 06Z THURSDAY.
STRONG WARM AIR ADVECTION WITH THIS WAVE AS H85 TEMPS PER RAP MODEL
ADVERTISING +8 TO +10C SOUTHEASTERN ALBERTA. THIS WILL SHIFT INTO
WESTERN AND PORTIONS OF CENTRAL NORTH DAKOTA FOLLOWING THE PASSAGE
OF THE SURFACE LOW LATE TONIGHT INTO THURSDAY. IN ADVANCE OF THE
LOW THIS AFTERNOON...WILL CONTINUE TO MENTION AN ISOLATED MIX IN
THE NORTH AS VERTICAL MOTION INCREASES IN ASSOCIATION WITH THE
LEFT EXIT REGION OF A 120KT JET. THE LIGHT PRECIPITATION THREAT
WILL EXPAND INTO THE JAMES RIVER VALLEY TONIGHT PER LATEST RAP/NAM/GFS.
PRECIPITATION AMOUNTS ARE VERY LIGHT. ADJUSTED THE HIGHS IN THE
SOUTHWEST UP A FEW DEGREES BASED ON LATEST OBSERVATIONS AND STILL
PLENTY OF TIME WITH AMPLE SUNSHINE THIS AFTERNOON TO RISE.
LATEST 12Z MODEL SUITE STILL ON TRACK FOR SNOW IN THE NORTH THURSDAY
NIGHT AND FRIDAY. THE POTENTIAL FOR FREEZING RAIN CONTINUES TO
SHRINK. THUS THE CURRENT THINKING RIGHT IS DOING A SPECIAL WEATHER
STATEMENT MOST LIKELY ALONG AND NORTH OF HIGHWAY 2 FOR THURSDAY
NIGHT AND FRIDAY WITH POSSIBLE ADVISORY LEVEL SNOW AMOUNTS. WILL
CONTINUE TO LOOK AT THINGS...BUT THAT IS THE DIRECTION WE ARE
LEANING TOWARDS AT THIS TIME.
&&
.AVIATION...FOR THE UPCOMING 18 UTC TAF CYCLE...VFR CONDITIONS WILL
PREVAIL ACROSS WESTERN AND CENTRAL NORTH DAKOTA FOR THE AFTERNOON
AND INTO THE EARLY EVENING AS HIGH PRESSURE ACROSS EASTERN NORTH
DAKOTA SHIFTS SLOWLY SOUTHEAST. HOWEVER...MVFR STRATUS CURRENTLY
ACROSS ALBERTA AS OF 17 UTC WILL CONTINUE TO MOVE SOUTHEAST SPREADING
ACROSS WESTERN AND CENTRAL NORTH DAKOTA LATE THIS EVENING AND
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...AYD