Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/15/11
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
940 AM EST TUE DEC 13 2011
.DISCUSSION...
MUCH DRIER DAY ACROSS EAST CENTRAL FLORIDA THIS MORNING WITH ONLY A
FEW LIGHT SHOWERS GENERATING OVER THE ATLANTIC WATERS AND
DIMINISHING AS THEY MOVE INTO THE COAST. LARGE LOW LEVEL HIGH
PRESSURE ACROSS THE EASTERN US WILL CONTINUE TO DRIVE THE WEATHER
ACROSS THE SOUTHEAST AS IT GENERATES A DEEP AND STEADY NORTHEASTERLY
FLOW. A STRONG UPPER LEVEL BUILDING INTO THE GULF OF MEXICO WILL
HAMPER ANY DEEPER CONVECTION FROM DEVELOPING AS THE SUBSIDENCE
INVERSION DEEPENS AROUND 700MB AND THE NW FLOW ALOFT BRINGS IN DRIER
AIR.
WILL KEEP THE MENTION OF ISOLATED LIGHT SHOWERS ALONG THE COAST
THROUGH EARLY AFTERNOON AND SPRINKLES OVER THE INTERIOR FOR THE WEAK
ACTIVITY THAT SURVIVES TO MAKE IT INLAND. BREEZY ONSHORE FLOW
WILL MAINTAIN A STRONG MARITIME INFLUENCE ACRS THE AREA...TEMPS WILL
CONTINUE ABV CLIMO WITH MAXES IN THE M/U70S...WITH A FEW LOCATIONS
POSSIBLY REACHING 80 WITH FEWER CLOUDS AND MORE SUNSHINE.
&&
.AVIATION...LINGERING IFR CIGS AND MVFR VSBYS IN FOG/STRATUS NORTH
AND WEST OF I-4 SLOWLY ERODING THROUGH 16Z. OTHERWISE...PREVAILING
VFR ALL SITES WITH CIGS BTWN FL040-060. BRIEF MVFR CIGS IN ISOLD
SHRA BRUSHING THE COAST AND OVER LCL ATLC. NE SFC WND G22-25KTS THRU
13/23Z.
&&
.MARINE...WINDS AT BUOY 41009 CONTINUE FROM THE NE TO OCCASIONALLY
ENE AT 15-20KTS THIS MORNING AS THE LARGE SFC HIGH OVER THE EASTERN
US CONTINUES TO GENERATE A MODERATE TO FRESH BREEZE ACROSS THE LOCAL
ATLC. THOUGH WINDS AT THE BUOY ARE SLIGHTLY BELOW SCA
CRITERIA...OBSERVATIONS JUST OUTSIDE OF OUR WATERS ARE RUNNING
CLOSER TO 20KTS WITH RUC ANALYSIS ALSO SHOWING THE SAME. WILL KEEP
THE FULL SCA UP THROUGH LATE TONIGHT TRANSITIONING TO A SCA FOR SEAS
THEREAFTER. THE LONG NE FETCH OVER THE WEST ATLC WILL CONTINUE TO
PUSH A LARGE SWELL INTO THE E FL COAST. SEAS 6-8FT NEARSHORE AND
8-10FT OFFSHORE THRU DAYBREAK WED. WAVE PDS WILL OPEN UP AS THE
WINDS DIMINISH...INCREASING FROM 8-9SEC TODAY TO 9-10SEC TONIGHT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR COASTAL
WATERS FROM FLAGLER BEACH TO JUPITER INLET OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM WEDNESDAY TO
7 AM EST THURSDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO
JUPITER INLET OUT 60 NM.
&&
$$
SHORT TERM/AVIATION...MOSES
LONG TERM/IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
330 AM EST TUE DEC 13 2011
.DISCUSSION...
TODAY-TONIGHT...
LARGE H100-H70 HI PRES RIDGE OVER THE SERN CONUS WILL SLOWLY WEAKEN
BUT WILL REMAIN THE DOMINANT WX FEATURE FOR THE FL PENINSULA AS IT
GENERATES A DEEP AND STEADY NE FLOW ACRS THE REGION. THESE WINDS
WILL PUSH DRIER AIR N OF THE BAHAMAS INTO CENTRAL FL THRU THE
DAY...LATEST RUC ANALYSIS SHOWS H100-H70 MEAN RH VALUES BLO 70PCT
AND H85-H50 VALUES BLO 50PCT.
ALOFT...A STRONG H85-H50 ANTICYCLONE OVER THE GOMEX WILL LIFT INTO
THE DEEP SOUTH. THIS WILL INCREASE THE STRENGTH OF A WEAK SUBSIDENCE
INVERSION IN THE H80-H60 LYR ACRS CENTRAL FL WHILE SIMULTANEOUSLY
PULLING DRY MID LVL AIR DOWN FROM THE N. MINIMAL H50 VORTICITY AND
H25 CONVERGENCE WILL FURTHER HAMPER ANY ORGANIZED PRECIP
KMLB PRECIP TREND HAS BEEN DIMINISHING STEADILY OVER THE PAST SVRL
HRS THOUGH KJAX SHOWS ONE REMAINING POCKET OF PRECIP PUSHING ONSHORE
N OF FLAGLER BEACH. MOST OF THIS PRECIP HAS FORMED OVER THE GULF
STREAM AND WILL WEAKEN AND DIMINISH AS IT MOVES OVER THE COOLER
SHELF WATERS. WILL KEEP SMALL COASTAL POPS IN THE FCST THRU EARLY
AFTN AS REMAINING DEEP MOISTURE PUSHES SW OF THE AREA...BUT IMPACT
WILL BE MINIMAL. DEEP/STEADY ONSHORE FLOW WILL MAINTAIN A STRONG
MARITIME INFLUENCE ACRS THE AREA...TEMPS WILL CONTINUE ABV CLIMO
WITH MAXES IN THE M/U70S...MINS M/U50S INTERIOR AND L/M60S ALONG THE
COAST.
WED-FRI...
AREA OF HIGH PRESSURE CENTERED NEAR THE MID ATLANTIC COAST WED WILL
SHIFT SOUTHEASTWARD WITH RIDGE AXIS BUILDING TOWARD NORTH FLORIDA
INTO LATE WEEK. THIS WILL ALLOW THE ELEVATED EASTERLY FLOW OVER
CENTRAL FLORIDA TO WEAKEN INTO FRI. BREEZY CONDS WILL STILL BE
LIKELY ALONG THE COAST WED WITH WINDS THEN AROUND 10-15 MPH OR LESS
BOTH THURS AND FRI. THE STRONGER ONSHORE FLOW WED MAY STILL ALLOW
FOR A FEW ONSHORE MOVING SPRINKLES BUT WITH A DRIER AIRMASS IN PLACE
DO NOT EXPECT ANY ACCUMULATING RAINFALL. OTHERWISE THE REST OF THE
WEEK LOOKS DRY WITH PARTLY CLOUDY SKIES AND ABOVE NORMAL TEMPS.
SAT-MON...
A S/W TROUGH PUSHING OFF THE EASTERN SEABOARD DEVELOPS AN AREA OF
LOW PRESSURE TOWARD THE CAROLINAS SATURDAY. LONG TERM MODELS MOVE
THIS LOW PRESSURE INTO THE ATLANTIC WITH A WEAK COLD FRONT PUSHING
ACROSS CENTRAL FLORIDA SAT NIGHT INTO SUN. MOISTURE ASSOCIATED WITH
THIS FRONT IS VERY WEAK WITH PW VALUES JUST BARELY OVER AN INCH.
WILL KEEP A SLIGHT CHANCE OF SHOWERS OVER THE AREA WITH THIS FRONTAL
PASSAGE...HOWEVER LOOKS LIKE BEST CHANCE FOR ANY PRECIPITATION WILL
PROBABLY BE LIMITED TO THE WARMER GULF STREAM WATERS. MODELS ONLY
INDICATING A SLIGHT COOL DOWN WITH THIS FRONT WITH MORE NORMAL TEMPS
SUN AND MON.
&&
.AVIATION...
THRU 13/15Z...WDSPRD IFR CIGS/AREAS LIFR CIGS NW OF I-4...PREVAILING
CIGS AOA FL030 ELSEWHERE WITH BRIEF MVFR CIGS/VSBYS IN ISOLD SHRAS S
OF KVRB. AFT 13/15Z...VFR ALL SITES WITH CIGS BTWN FL040-060...NE
SFC WND G22-25KTS THRU 13/23Z.
&&
.MARINE...
TODAY-TONIGHT...HI PRES RIDGE OVER THE SE CONUS WILL MAINTAIN A
MODERATE TO FRESH NE BREEZE ACRS THE LCL ATLC. SFC/BNDRY LYR WINDS
WILL DIMINISH BLO 20KTS AFT MIDNIGHT AS THE RIDGE BEGINS TO
WEAKEN...THOUGH A LONG NE FETCH OVER THE W ATLC WILL CONTINUE TO
PUSH A LARGE SWELL INTO THE E FL COAST. SEAS 6-8FT NEARSHORE AND
8-10FT OFFSHORE THRU DAYBREAK WED. WAVE PDS WILL OPEN UP AS THE
WINDS DIMINISH...INCREASING FROM 8-9SEC TODAY TO 9-10SEC TONIGHT.
FULL SCA WILL CONTINUE THRU 09Z...SCA FOR SEAS AFT 09Z.
WED-SAT...ELEVATED ONSHORE WINDS WILL LIKELY CONTINUE UP TO 15-20
KTS WED AND WED NIGHT AND COMBINE WITH A LONG NORTHEASTERLY FETCH TO
KEEP SEAS UP TO 7 TO 9 FT. RIDGE AXIS BUILDING TOWARD NORTH FLORIDA
INTO LATE WEEK WILL THEN WEAKEN THE ONSHORE FLOW WITH SEAS SLOWLY
SUBSIDING INTO THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 61 75 59 / 20 10 10 10
MCO 78 58 78 58 / 10 0 10 10
MLB 78 67 77 65 / 20 10 10 10
VRB 78 66 77 65 / 20 10 10 10
LEE 76 56 77 57 / 10 0 10 10
SFB 78 58 77 58 / 10 0 10 10
ORL 78 59 77 59 / 10 0 10 10
FPR 78 66 77 64 / 20 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR COASTAL
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20
NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20
NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET OUT 20 NM-WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD
COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO
JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM WEDNESDAY TO
7 AM EST THURSDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO
VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM
SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM
VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM
OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60
NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO
SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...WEITLICH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1257 AM EST TUE DEC 13 2011
.SYNOPSIS...
SURFACE HIGH PRESSURE CENTERED NORTH OF THE AREA WILL PERSIST
THROUGH MID WEEK BEFORE WEAKENING AND SHIFTING OFFSHORE LATE IN
THE WEEK. A COLD FRONT COULD STALL OVER OR NEAR THE REGION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DRY CONDITIONS ARE EXPECTED OVERNIGHT AS HIGH PRESSURE HOLDS FIRM
ACROSS MUCH OF THE SOUTHEAST UNITED STATES. HAVE MADE SOME FAIRLY
SIZABLE CHANGES TO THE GRIDS AND TEXT PRODUCTS FOR THE OVERNIGHT
PERIOD AS SHORTER TERM TRENDS ARE FINALLY BECOMING MORE APPARENT.
CONFIDENCE IS INCREASING THAT THE POTENTIAL FOR A WIDESPREAD
STRATUS/FOG EVENT IS DIMINISHING WITH TIME AS THE LOWER
TROPOSPHERE CONTINUES TO DRY OUT. 13/01Z RUC SOUNDINGS SUGGEST AN
ENHANCED BOUNDARY LAYER WIND FIELD WILL LIKELY SEVERELY CURTAIL
THE WIDESPREAD FOG POTENTIAL AND ALTHOUGH PATCHES OF STRATUS ARE
LIKELY TO REFORM PRIOR TO DAYBREAK...SUSPECT THE THICKEST STRATUS
DECK ALONG WITH SOME PATCHY FOG WILL REMAIN MAINLY S OF I-16 IN
GEORGIA. WILL GO WITH A GENERAL PARTLY CLOUDY SKY FORECAST THROUGH
SUNRISE FOR THIS REASON...ALTHOUGH THERE WILL BE SOME FAIRLY
SIZABLE CLEAR PERIODS THIS EVENING. LOWS FROM THE UPPER 30S WELL
INLAND TO THE MID 40S AT THE COAST LOOK ON TRACK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
PRETTY GOOD MODEL AGREEMENT FOR MID WEEK WITH SURFACE HIGH PRESSURE
CENTERED NORTH OF THE AREA SLOWLY SHIFTING EAST INTO THE ATLANTIC.
MEANWHILE...HIGH PRESSURE ALOFT WILL BECOME STRONGER THROUGH
WEDNESDAY BEFORE WEAKENING THURSDAY AS A COLD FRONT BEGINS TO
APPROACH FROM THE WEST. EXPECT A DRY PERIOD WITH THE LACK OF DEEP
MOISTURE. TEMPERATURES WILL BE ON A SLOW WARMING TREND...REACHING
WELL ABOVE NORMAL LEVELS THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE UPPER LEVEL PATTERN WILL BECOME ZONAL LATE IN THE WEEK...ALLOWING
A BACKDOOR COLD FRONT TO SLOWLY SINK SOUTH INTO THE AREA OVER THE
WEEKEND. GUIDANCE REMAINS IN DISAGREEMENT AS TO WHEN THE FRONT
WILL PUSH THROUGH THE AREA SO HAVE MADE NO CHANGES TO THIS PORTION
OF THE FORECAST WHICH CURRENTLY HAS SLIGHT RAIN CHANCES FRIDAY
NIGHT THROUGH SATURDAY NIGHT. UPPER LEVEL HIGH PRESSURE WILL THEN
RETURN BRIEFLY EARLY NEXT WEEK BEFORE THE NEXT STORM SYSTEM BEGINS
TO APPROACH FROM THE WEST. TEMPERATURES GENERALLY ABOVE NORMAL
THROUGH THE PERIOD...EVEN BEHIND THE COLD FRONT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SKIES HAVE CLEARED OVER THE COASTAL CORRIDOR EARLY THIS MORNING
AND VFR CONDITIONS WILL PERSIST BUT THERE COULD BE AN EXCEPTION A
FEW HOURS AROUND DAYBREAK IF FOG AND/OR STRATUS CLOUDS DEVELOP.
LATEST DATA SUGGESTS ALMOST A COIN-FLIP SCENARIO AS LOWEST LEVEL
NNE WINDS A BIT STRONG DESPITE FOG STABILITY INDICES BELOW 15 ON
FORECAST SOUNDINGS AT BOTH TERMINALS JUST BEFORE DAWN. GIVEN ALL
THE RAIN AT KSAV...WE HIT SOME IFR POTENTIAL AND MAINTAINED JUST
CURSORY MENTION OF MVFR VSBYS AND A FEW SCATTERED STRATUS AT KCHS.
EXTENDED AVIATION OUTLOOK...PATCHY MVFR CONDITIONS POSSIBLE IN
EARLY MORNING FOG ON WED...OTHERWISE MAINLY VFR.
&&
.MARINE...
BUOY AND PILOT BOAT REPORTS INDICATE SEAS HAVE DROPPED BELOW 6 FT
ACROSS THE SOUTH CAROLINA LEGS SO THE SMALL CRAFT ADVISORY HAS
BEEN CANCELLED FOR AMZ350-352. LOOKS LIKE MARGINAL 6 FT SEAS WILL
CONTINUE FOR SEVERAL MORE HOURS OVER THE GEORGIA NEARSHORE WATERS
WHERE FLAGS REMAIN IN FORCE UNTIL 5 AM TUESDAY. SOLID SMALL CRAFT
ADVISORY CONDITIONS WILL PERSIST OVER THE GEORGIA OFFSHORE WATERS
THROUGH THE NIGHT.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL REMAIN CENTERED NORTH
OF THE WATERS THROUGH WEDNESDAY BEFORE SHIFTING EAST ON THURSDAY. A
COLD FRONT WILL THEN APPROACH LATE IN THE WEEK BEFORE EVENTUALLY
PUSHING THROUGH THE AREA OVER THE WEEKEND. EXPECT WINDS TO DECREASE
SIGNIFICANTLY TUESDAY AS THE HIGH WEAKENS. SEAS WILL SLOWLY SUBSIDE
ALONG WITH THE WINDS WITH ADVISORY CONDITIONS PERSISTING BEYOND 20
NM THROUGH WEDNESDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
AMZ354.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
839 PM CST WED DEC 14 2011
.DISCUSSION...
ISSUED 830 PM CST WED DEC 14 2011
RATHER IMPRESSIVE UPPER LEVEL WAVE AND SPEED MAX SEEN ON WATER
VAPOR LOOP THIS EVENING ACRS OKLAHOMA...WHICH IS TRACKING
NE AND BRINGING IN ANOTHER ROUND OF RAIN AND THUNDERSTORMS...
THIS TIME TO THE SOUTHERN HALF OF THE FORECAST AREA. FURTHER
NORTH AND WEST...STILL SEEING SOME PRECIP...BUT MORE LIGHT
RAIN AND DRIZZLE THAN THE STEADIER RAINS THAT OCCURRED IN THIS
AREA THRU MOST OF THE DAY. RAINFALL TOTALS RANGED FROM 2 TO 3
INCHES ROUGHLY ALONG AND NORTH OF A RUSHVILLE TO BLOOMINGTON
LINE...WITH TOTALS DROPPING OFF DRAMATICALLY TO THE SOUTH.
HIGHEST POPS WILL CONTINUE ACRS THE SOUTHEAST HALF OF THE FORECAST
AREA FOR THE REST OF THIS EVENING AND INTO THE EARLY MORNING HOURS.
THE COMBINATION OF THE CLOUD COVER AND GUSTY SOUTH WINDS WILL KEEP
TEMPS STEADY THRU THE NIGHT...AND SOME 10 TO 15 DEGREES ABOVE NORMAL
HIGH TEMPERATURES FOR THIS TIME OF YEAR! THE COLD FRONT WHICH IS
SLATED TO MOVE THRU PIA AROUND 3 OR 4 AM WAS JUST EAST OF DES MOINES
THIS EVENING...WITH SURFACE DEW POINTS IN THE MID TO UPPER 50S
STREAMING NORTH JUST AHEAD OF THE BOUNDARY. PRECIP WILL END LAST
ACRS THE FAR SOUTHEAST EITHER LATE TOMORROW MORNING OR EARLY
AFTERNOON AS THE SURFACE LOW DEEPENS OVER THE UPPER GREAT LAKES
DRAWING DOWN COLDER AIR FOR THE REST OF THE WORK WEEK. HAVE ADJUSTED
POPS OUT A BIT LATER INTO THE OVERNIGHT HOURS ACRS MAINLY OUR EAST
AND SOUTHERN AREAS...BASED ON THE BAND OF RAIN AND ISOLD THUNDERSTORMS
OCCURRING FROM EAST CENTRAL IL SOUTHWEST THRU SOUTH CENTRAL MISSOURI.
SHOULD HAVE THE UPDATED ZONES OUT BY 900 PM.
SMITH
&&
.AVIATION...
ISSUED 525 PM CST WED DEC 14 2011
RAIN CONTINUES TO MOVE STEADILY EAST LATE THIS AFTERNOON AND BASED
ON EXTRAPOLATION...IT APPEARS THE STEADIER RAINS SHOULD PUSH EAST
OF CMI BY 700 PM THIS EVENING. WHETHER OR NOT ANOTHER ROUND OF RAIN
PUSHES NE OUT OF MO INTO EAST CENTRAL IL IS PROBLEMATIC AT THIS
POINT...AND IT APPEARS AREAS TO THE SOUTH OF OUR TAF SITES STAND A
BETTER CHANCE FOR SEEING STEADY RAINS THIS EVENING ONCE THIS LARGE
BAND OF RAIN AND ISOLD THUNDER MOVES TO OUR EAST. FORECAST SOUNDINGS
INDICATE MORE DRIZZLE OR LIGHT RAIN POTENTIAL TONIGHT RATHER THAN
SHOWERS AS MODELS SUGGEST DRIER AIR WORKING ITS WAY IN AT THE MID
LEVELS WITH THE DEEPER MOISTURE PROFILES SHIFTING OFF TO OUR EAST
AND SOUTH THIS EVENING. IFR CIGS EXPECTED TO HOLD ACRS THE AREA
THRU THE NIGHT AND INTO AT LEAST THE MORNING HOURS OF THURSDAY.
AS THE SYSTEM DEEPENS OVER THE UPPER GREAT LAKES TOMORROW...BROAD
CYCLONIC FLOW SHOULD KEEP THE STRATUS DECK OVER OUR AREA INTO THE
EARLY AFTN HOURS WITH FORECAST SOUNDINGS SHOWING A FAIRLY SUBSTANTIAL
SUBSIDENCE INVERSION IN PLACE WHICH WOULD PREVENT MUCH IF ANY CLEARING
UNTIL MID AFTERNOON OR LATER. SURFACE WINDS WILL CONTINUE OUT OF THE
SOUTH AT 15 TO 25 KTS WITH AN OCCASIONAL GUST APPRCHG 30TS...WITH
SFC WINDS VEERING MORE INTO THE SOUTHWEST LATER TONIGHT AS A COLD
FRONT APPROACHES. WINDS ON THU WILL BE OUT OF THE WEST TO NORTHWEST
AT 15 TO 20 KTS WITH GUSTS AROUND 25 KTS AT TIMES.
SMITH
&&
.PREV DISCUSSION...
ISSUED 238 PM CST WED DEC 14 2011
SPRING-LIKE STORM SYSTEM BRINGING SHOWERS AND SCATTERED
THUNDERSTORMS TO THE CENTRAL/NORTHERN CWA TODAY IN BROAD...WARM
SOUTHWEST FLOW. HEAVIEST RAINS OF 1.5-2.5 INCHES HAVE FALLEN NORTH
OF A BEARDSTOWN TO BLOOMINGTON LINE. MODERATE RAINFALL RATES AND
UNFROZEN GROUND HAVE PRODUCED LITTLE IN THE WAY OF WATER PROBLEMS.
UPPER LEVEL DYNAMICS HELPING DRIVE THIS ACTIVITY AS SFC LOW AND
FRONT ANALYZED AT 19Z ACROSS EASTERN NEB/NRN KS. EVEN WITH THICK
CLOUDS AND RAIN...EARLY AFTERNOON TEMPS WERE RUNNING 15-20 DEGREES
ABOVE NORMAL. SHORT TERM FORECAST ISSUE IS ENDING OF RAIN WITH
COLD FRONTAL PASSAGE LATE TONIGHT AND RETURN TO SEASONABLE TEMPS.
BEYOND...NEXT MAJOR SYSTEM LOOKS TO IMPACT REGION EARLY NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY
UNSEASONABLY HIGH P/W VALUES AROUND 1.25 INCHES AND STRONG FORCING
ALOFT WILL CONTINUE TO DRIVE MODERATE RAIN AND EMBEDDED
THUNDERSTORMS THIS EVENING. LATEST HIGH RES NAM AND HRRR RUNS SHOW
ROUNDS OF CONVECTION TRANSLATING EAST ACROSS THE CWA THROUGH LATE
EVENING. PLENTY OF ELEVATED INSTABILITY FOR THUNDER...AND VERY
STRONG LLJ OVERHEAD /1 KM AGL WINDS 50 KTS/ BUT DUE TO STRONG LOW
LEVEL INVERSION DO NOT EXPECT ANY OF THIS TO MAKE IT DOWN TO THE
SURFACE. MAIN BATCH OF RAIN ASSOCIATED WITH PRE-FRONTAL TROUGH
LOOKS TO PUSH INTO INDIANA AFTER MIDNIGHT...WHEN THE ACTUAL COLD
FRONT ENTERS THE NW CWA. EXPECT A LINE OF SCATTERED SHOWERS
ALONG/AHEAD OF THE FRONT...WHICH WILL EXIT THE SE CWA AROUND 15Z
THU. BRISK WEST WINDS GUSTING TO 20-25 MPH WILL MOVE IN BEHIND THE
FRONT...BRINGING IN COOLER AND DRIER AIR.
CLOUD FORECAST FOR THURSDAY IS PROBLEMATIC WITH DRY AIR ADVECTING
IN...BUT FCST SOUNDINGS SHOW A SHALLOW LAYER OF MOISTURE TRAPPED
BENEATH A SHARP SUBSIDENCE INVERSION AROUND 925 MB. THIS COMBINED
WITH CYCLONIC FLOW ALOFT AND WEAK SUN ANGLE MAKES A LOW STRATUS
DECK LOOK LIKELY TO HOLD AT LEAST INTO MID AFTERNOON. TEMPERATURES
MAY HOLD STEADY FOR A FEW HOURS IN THE MORNING...THEN SLOWLY FALL
THROUGH THE AFTERNOON WHEN STRONGER CAA KICKS IN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
QUIET AND SEASONABLE WEATHER IS ON TAP FOR THE FRIDAY INTO SUNDAY
PERIOD. ZONAL/WNW FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL
BE RESPONSIBLE FOR THE TRANQUIL CONDITIONS. AS THE HIGH SHIFTS OFF
TO THE SOUTHEAST LATE IN THE WEEKEND SOUTHERLY FLOW DEVELOPS AHEAD
OF THE NEXT SYSTEM IN THE SW.
CURRENT INDICATIONS SHOW THIS EVENT MAY BE SIMILAR TO THE STORM
THAT IS CURRENTLY IMPACTING THE AREA. THE 12Z ECMWF AND CANADIAN GEM
ARE SIMILAR IN TRACKING A STRONG LOW FROM THE TX PANHANDLE REGION
MONDAY MORNING...INTO THE LOWER GREAT LAKES BY TUESDAY EVENING.
12Z GFS IS MUCH SLOWER AND FARTHER SOUTH AND WAS NOT FOLLOWED FOR
THIS FORECAST. EVENTUAL LOW TRACK WILL DETERMINE EXACT PRECIP TYPE
AND AMOUNTS...BUT CURRENT SOLUTION WOULD POINT TO PRIMARILY
ANOTHER MODERATE RAIN EVENT FOR THE CWA FOR SUNDAY NIGHT INTO TUESDAY.
LATER MODEL RUNS WILL NEED TO BE MONITORED...AS ECMWF DIGS A
NORTHERN STREAM WAVE INTO THE MIDWEST FOR A MORE PHASED SYSTEM AND
POTENTIAL SNOW BAND ON THE NW SIDE OF THE STORM. AFTER A BRIEF
SHOT OF COLDER AIR BEHIND THIS LOW...ZONAL FLOW LOOKS TO MODERATE
TEMPS FOR MID WEEK.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
535 PM CST WED DEC 14 2011
.DISCUSSION...
ISSUED 238 PM CST WED DEC 14 2011
SPRING-LIKE STORM SYSTEM BRINGING SHOWERS AND SCATTERED
THUNDERSTORMS TO THE CENTRAL/NORTHERN CWA TODAY IN BROAD...WARM
SOUTHWEST FLOW. HEAVIEST RAINS OF 1.5-2.5 INCHES HAVE FALLEN NORTH
OF A BEARDSTOWN TO BLOOMINGTON LINE. MODERATE RAINFALL RATES AND
UNFROZEN GROUND HAVE PRODUCED LITTLE IN THE WAY OF WATER PROBLEMS.
UPPER LEVEL DYNAMICS HELPING DRIVE THIS ACTIVITY AS SFC LOW AND
FRONT ANALYZED AT 19Z ACROSS EASTERN NEB/NRN KS. EVEN WITH THICK
CLOUDS AND RAIN...EARLY AFTERNOON TEMPS WERE RUNNING 15-20 DEGREES
ABOVE NORMAL. SHORT TERM FORECAST ISSUE IS ENDING OF RAIN WITH
COLD FRONTAL PASSAGE LATE TONIGHT AND RETURN TO SEASONABLE TEMPS.
BEYOND...NEXT MAJOR SYSTEM LOOKS TO IMPACT REGION EARLY NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY
UNSEASONABLY HIGH P/W VALUES AROUND 1.25 INCHES AND STRONG FORCING
ALOFT WILL CONTINUE TO DRIVE MODERATE RAIN AND EMBEDDED
THUNDERSTORMS THIS EVENING. LATEST HIGH RES NAM AND HRRR RUNS SHOW
ROUNDS OF CONVECTION TRANSLATING EAST ACROSS THE CWA THROUGH LATE
EVENING. PLENTY OF ELEVATED INSTABILITY FOR THUNDER...AND VERY
STRONG LLJ OVERHEAD /1 KM AGL WINDS 50 KTS/ BUT DUE TO STRONG LOW
LEVEL INVERSION DO NOT EXPECT ANY OF THIS TO MAKE IT DOWN TO THE
SURFACE. MAIN BATCH OF RAIN ASSOCIATED WITH PRE-FRONTAL TROUGH
LOOKS TO PUSH INTO INDIANA AFTER MIDNIGHT...WHEN THE ACTUAL COLD
FRONT ENTERS THE NW CWA. EXPECT A LINE OF SCATTERED SHOWERS
ALONG/AHEAD OF THE FRONT...WHICH WILL EXIT THE SE CWA AROUND 15Z
THU. BRISK WEST WINDS GUSTING TO 20-25 MPH WILL MOVE IN BEHIND THE
FRONT...BRINGING IN COOLER AND DRIER AIR.
CLOUD FORECAST FOR THURSDAY IS PROBLEMATIC WITH DRY AIR ADVECTING
IN...BUT FCST SOUNDINGS SHOW A SHALLOW LAYER OF MOISTURE TRAPPED
BENEATH A SHARP SUBSIDENCE INVERSION AROUND 925 MB. THIS COMBINED
WITH CYCLONIC FLOW ALOFT AND WEAK SUN ANGLE MAKES A LOW STRATUS
DECK LOOK LIKELY TO HOLD AT LEAST INTO MID AFTERNOON. TEMPERATURES
MAY HOLD STEADY FOR A FEW HOURS IN THE MORNING...THEN SLOWLY FALL
THROUGH THE AFTERNOON WHEN STRONGER CAA KICKS IN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
QUIET AND SEASONABLE WEATHER IS ON TAP FOR THE FRIDAY INTO SUNDAY
PERIOD. ZONAL/WNW FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL
BE RESPONSIBLE FOR THE TRANQUIL CONDITIONS. AS THE HIGH SHIFTS OFF
TO THE SOUTHEAST LATE IN THE WEEKEND SOUTHERLY FLOW DEVELOPS AHEAD
OF THE NEXT SYSTEM IN THE SW.
CURRENT INDICATIONS SHOW THIS EVENT MAY BE SIMILAR TO THE STORM
THAT IS CURRENTLY IMPACTING THE AREA. THE 12Z ECMWF AND CANADIAN GEM
ARE SIMILAR IN TRACKING A STRONG LOW FROM THE TX PANHANDLE REGION
MONDAY MORNING...INTO THE LOWER GREAT LAKES BY TUESDAY EVENING.
12Z GFS IS MUCH SLOWER AND FARTHER SOUTH AND WAS NOT FOLLOWED FOR
THIS FORECAST. EVENTUAL LOW TRACK WILL DETERMINE EXACT PRECIP TYPE
AND AMOUNTS...BUT CURRENT SOLUTION WOULD POINT TO PRIMARILY
ANOTHER MODERATE RAIN EVENT FOR THE CWA FOR SUNDAY NIGHT INTO TUESDAY.
LATER MODEL RUNS WILL NEED TO BE MONITORED...AS ECMWF DIGS A
NORTHERN STREAM WAVE INTO THE MIDWEST FOR A MORE PHASED SYSTEM AND
POTENTIAL SNOW BAND ON THE NW SIDE OF THE STORM. AFTER A BRIEF
SHOT OF COLDER AIR BEHIND THIS LOW...ZONAL FLOW LOOKS TO MODERATE
TEMPS FOR MID WEEK.
&&
.AVIATION...
ISSUED 525 PM CST WED DEC 14 2011
RAIN CONTINUES TO MOVE STEADILY EAST LATE THIS AFTERNOON AND BASED
ON EXTRAPOLATION...IT APPEARS THE STEADIER RAINS SHOULD PUSH EAST
OF CMI BY 700 PM THIS EVENING. WHETHER OR NOT ANOTHER ROUND OF RAIN
PUSHES NE OUT OF MO INTO EAST CENTRAL IL IS PROBLEMATIC AT THIS
POINT...AND IT APPEARS AREAS TO THE SOUTH OF OUR TAF SITES STAND A
BETTER CHANCE FOR SEEING STEADY RAINS THIS EVENING ONCE THIS LARGE
BAND OF RAIN AND ISOLD THUNDER MOVES TO OUR EAST. FORECAST SOUNDINGS
INDICATE MORE DRIZZLE OR LIGHT RAIN POTENTIAL TONIGHT RATHER THAN
SHOWERS AS MODELS SUGGEST DRIER AIR WORKING ITS WAY IN AT THE MID
LEVELS WITH THE DEEPER MOISTURE PROFILES SHIFTING OFF TO OUR EAST
AND SOUTH THIS EVENING. IFR CIGS EXPECTED TO HOLD ACRS THE AREA
THRU THE NIGHT AND INTO AT LEAST THE MORNING HOURS OF THURSDAY.
AS THE SYSTEM DEEPENS OVER THE UPPER GREAT LAKES TOMORROW...BROAD
CYCLONIC FLOW SHOULD KEEP THE STRATUS DECK OVER OUR AREA INTO THE
EARLY AFTN HOURS WITH FORECAST SOUNDINGS SHOWING A FAIRLY SUBSTANTIAL
SUBSIDENCE INVERSION IN PLACE WHICH WOULD PREVENT MUCH IF ANY CLEARING
UNTIL MID AFTERNOON OR LATER. SURFACE WINDS WILL CONTINUE OUT OF THE
SOUTH AT 15 TO 25 KTS WITH AN OCCASIONAL GUST APPRCHG 30TS...WITH
SFC WINDS VEERING MORE INTO THE SOUTHWEST LATER TONIGHT AS A COLD
FRONT APPROACHES. WINDS ON THU WILL BE OUT OF THE WEST TO NORTHWEST
AT 15 TO 20 KTS WITH GUSTS AROUND 25 KTS AT TIMES.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
754 PM EST WED DEC 14 2011
.AVIATION...
CONDS TO QUICKLY DETERIORATE TO IFR/LIFR MET CONDS PRIMARILY DUE TO
CIGS AS MASSIVE RAIN SHIELD W/EMBEDDED CONVECTIVE ELEMENTS
OVERSPREADS NRN IN. POINT CHCS FOR TSRA HIEST INVOF KFWA...THOUGH
LOW ENOUGH TO PRECLUDE CAT/TEMPO MENTION ATTM AND RELEGATE TO CB
MENTION. LLWS CONTS WITH RAMPED SSWRLY LLJ 50-60 KTS. CORE OF JET
TRANSLATES EWD OVERNIGHT W/ THREAT DIMINISHING AT KSBN...THOUGH CONT
AT KFWA UNTIL COLD FROPA MID/LATE THU AM. CIGS IMPROVING TO MVFR THU
AFTN...THOUGH FUEL ALT CONDS MAY PERSIST.
&&
.SHORT TERM...
TONIGHT THROUGH THURSDAY NIGHT...
KIWX RADAR DEPICTING BAND OF MOD/HVY RAIN ALONG/AHEAD OF WARM FRONT
LIFTING NORTH THROUGH THE AREA THIS AFTERNOON. THIS IS IN
ASSOCIATION WITH DEVELOPING SFC LOW IN CENTRAL PLAINS. WATER VAPOR
IMAGERY AND LATEST RUC ANALYSIS SHOWING LEAD SHORT WAVE EJECTING OUT
OF FOUR CORNERS AND WILL COMBINE WITH COUPLED JET STRUCTURE FROM
NORTHERN GREAT LAKES DOWN INTO THE CENTRAL PLAINS TO DEEPEN SFC LOW
AND DRIVE IT INTO WESTERN GREAT LAKES THIS EVENING. THIS WILL
PLACE THE FCST AREA IN ENHANCED MOIST SOUTHERLY FLOW IN THE WARM
SECTOR AND SUPPORT ANOTHER ROUND OF PRECIPITATION TONIGHT. COLD
FRONT WILL MOVE THROUGH THE AREA ON THURSDAY AND BRING AN END TO
RAIN BY 18Z. SIGNIFICANT DRYING BEHIND THE FRONT ALONG WITH MARGINAL
DELTA T WILL PROVIDE LITTLE SUPPORT FOR LES IN THE WAKE OF THIS
SYSTEM SO FAVOR CURRENT GRIDS IN KEEPING JUST A MENTION OF FLURRIES
ATTM. FIRST TWO PERIODS OF FCST WILL FEATURE NON-DIURNAL TEMP
PATTERN AS WARM FRONT LIFTING NORTH OF THE AREA TONIGHT WILL KEEP
TEMPS STEADY/SLOWLY RISING...THEN CAA BEHIND PASSAGE OF COLD FRONT
THURSDAY WILL SEE HIGHS REACHED IN THE MORNING FOLLOWED BY FALLING
TEMPS IN THE AFTERNOON. COOLER BUT SEASONABLE TEMPS THURSDAY NIGHT
WITH LOWS IN THE MID-UPPER 20S.
&&
.LONG TERM...
FRIDAY THROUGH WEDNESDAY
ACTIVE NORTHERN STREAM WILL INFLUENCE LOWER HEIGHTS INTO THE REGION
THIS WEEKEND WITH COLDER/DRIER AIR PUSHING INTO THE GREAT LAKES...AS
PERIPHERY DISTURBANCES ADVECT THROUGH THE FLOW. A SERIES OF THESE
WEAK INFLUENCES MAY INFLUENCE ENOUGH LIFT AND COLUMN SATURATION TO
SUPPORT LIGHT SNOW OR FLURRIES ACROSS THE NORTH...ALONG WITH A WEAK
LAKE RESPONSE. OTHERWISE...MODELS AND ENSEMBLES CONTINUE TO SUPPORT
THE EJECTION OF A SW CONUS DISTURBANCE INTO THE REGION BY EARLY NEXT
WEEK...WITH SOME RATHER SIG DISCREPANCIES AMONG DETERMINISTIC
SOLUTIONS. WILL STAY THE COURSE WITH PERSISTENCE...FAVORING THE
WARMER ECMWF AND GEM. THIS WILL ESP BE TRUE IF FLOW PHASING IS
REALIZED...WHICH IS CERTAINLY POSSIBLE GIVEN THE PATTERN. SMALL
ADJUSTMENT MADE TO THE PREVIOUS FORECAST...GENERALLY TO POPS/WX.
FRI-SUN...OVERALL DRY/SLIGHTLY DISTURBED FLOW WILL REMAIN IN THE
GREAT LAKES REGION. CONTINUED TO OPT NOT TO INCLUDE A LAKE EFFECT
SNOW SHOWER MENTION FRI-SAT FAR NW GIVEN MARGINAL SUPPORT FOR LAKE
INDUCE CONVECTION...WITH ONLY A FLURRY MENTION ATTM...SPREAD OVER
THE ENTIRE NORTH TO COVER THE POTENTIAL FOR LIGHT SNOW WITH ANY OF
THE WEAK DISTURBANCES. PROFILES INDICATE SIG DRYING IN THE SFC TO H8
LAYER WITH MARGINAL DELTA T/S PRESENT. CANNOT RULE OUT A FEW
FLURRIES OR LIGHT LAKE EFFECT SNOW SHOWERS IF COLDER PROFILES
VERIFY...COUPLED WITH A WEAK NORTHERN STREAM DISTURBANCE PROGGED
INTO THE REGION...WHICH COULD GENERATE ENOUGH INVERSION HEIGHT
UNDULATION TO SUPPORT PERHAPS A FEW SNOW SHOWERS/FLURRIES IN SHORT
FETCH WESTERLY FLOW. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN AROUND
NORMAL TO SLIGHTLY ABOVE IN THE PERIOD...WITH LAKE EFFECT CLOUDS
ACROSS NORTHERN AREAS LINGERING THROUGH SAT.
MON-WED...CHANCES FOR A DECENT STORM SYSTEM CONTINUE...AS AN ACTIVE
NORTHERN STREAM IMPULSE LIKELY INTERACTS WITH ANOTHER SW CONUS
UPPER LOW. ADVECTION TIMING/THERMAL FIELDS/AND HEIGHT FALL DEPTH
INTO THE REGION IS STILL MUCH UNCERTAIN...BUT GIVEN THE GFS/S
TENDENCY TOWARD PROGRESSIVE FLOW...LIKELY BIASING THE NAEFS
SOLUTIONS...HAVE CONTINUED TO SIDE TOWARD THE MORE RELIABLE ECMWF. A
TREND TO A DEEPER H5 SOLUTION WOULD CERTAINLY BE NEEDED...ESP IF
WAVE PHASING RESULTS...WITH COUPLED JET DYNAMICS LIKELY SHIFTING THE
SFC LOW TRACK NW OF THE FA...AS SEEN IN THE GEM. RETAINED A
RAIN/SNOW MENTION IN MOST PERIODS...MAINLY TO COVER
UNCERTAINTY...BUT IT CERTAINLY LOOKS LIKE RAIN WILL BE THE DOMINATE
WEATHER TYPE IN THE PERIOD...ESP SE HALF. CONTINUE TO EXPECT MORE
ADJUSTMENT IN THIS PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING UNTIL 11 PM EST THURSDAY FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JC
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
849 PM CST WED DEC 14 2011
.AVIATION...
ALONG THE COLD FRONT CLOUD CIELINGS AND VISIBILITIES HAVE RISEN TO
VFR CATEGORY...FOR AT LEAST A SHORT WHILE. A FEW HOURS LATER...IT
APPEARS THAT LOW STRATUS WILL SWEEP BACK INTO THE TERMINALS FROM
THE NORTHWEST. THUS...HAVE UPDATED KCID...KMLI AND KBRL FOR THIS
IMPROVEMENT TREND. AT THIS TIME IT APPEARS THAT KDBQ WILL NOT GET
THIS IMPROVEMENT TREND...BUT WILL HAVE TO MONITOR TO SEE IF THIS
NEEDS CHANGING. ..LE..
&&
.PREV DISCUSSION... /ISSUED 319 PM CST WED DEC 14 2011/
SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB WARM FRONT FROM SOUTH DAKOTA INTO
SOUTHERN WISCONSIN. A LLJ RAN FROM THE WESTERN GREAT LAKES TO NORTH
TEXAS WITH THE STRONG CORE OF 50-55 KNOTS FROM EASTERN KANSAS INTO
NORTH TEXAS. A STRONG MOISTURE FEED RAN FROM THE GULF COAST INTO THE
WESTERN GREAT LAKES. RADAR TRENDS SHOW THE CONVECTION AND
THUNDERSTORMS HAVE SHIFTED INTO EASTERN ILLINOIS WITH PRECIPITATION
INTENSITY DECREASING ACROSS IOWA AND MISSOURI.
18Z SFC ANALYSIS HAD A WEAK LOW NEAR KLNK WITH A WARM FRONT ALONG
THE IA/MO BORDER INTO CENTRAL ILLINOIS. A COLD FRONT RAN FROM THE
LOW BACK INTO SOUTHEAST COLORADO. DEW POINTS SOUTH OF THE WARM FRONT
WERE IN THE 50S AND 60S.
SHORT TERM...TONIGHT AND THURSDAY...
THE RUC HAS BEEN DOING A REASONABLE JOB OF HANDLING THE IMMEDIATE
SHORT TERM AND THE TRENDS OF THE RUC WERE FOLLOWED FOR INPUT TONIGHT.
THE LIFT TOOL INDICATES THE THREAT OF THUNDER IS NOW OVER WITH THE
PASSAGE OF A STRONG VORT MAX. OVERALL PRECIPITATION INTENSITY WILL
NOW BE LIGHT DURING THE EVENING HOURS WITH EVERYTHING TRANSITIONING
TO MORE DRIZZLE WITH TIME. THUS DRIZZLE WITH SOME RAIN WILL BE SEEN
DURING THE EVENING HOURS ALONG WITH PATCHY FOG. AFTER MIDNIGHT...
CONDENSATION PRESSURE DEFICITS SLOWLY RISE IN THE WEST WITH THE
BETTER FORCING SHIFTING EAST OF THE MISSISSIPPI. THE RUC DOES SHOW
ANOTHER ROUND OF FORCING ARRIVING AROUND MIDNIGHT IN THE WESTERN
CWFA. THUS WILL CONTINUE THE DRIZZLE WITH OVERALL LOWER CHANCES OF
RAIN. PATCHY FOG WILL STILL BE AN ISSUE AFTER MIDNIGHT.
THE OVERALL DENSE FOG IS PATCHY IN NATURE AND GENERALLY CONFINED TO
THE HWY 20 CORRIDOR. THE MORE WIDESPREAD AND LIKELY DENSE FOG SHOULD
BE SEEN ACROSS WISCONSIN AND MINNESOTA WHERE THE SFC LOW TRACKS.
THE COLD FRONT WILL MOVE THROUGH THE CWFA AFTER MIDNIGHT. WINDS
SHOULD REMAIN UP WHICH WILL KEEP THE FOG FROM GETTING TOO DENSE AS
THE OVERALL ATMOSPHERIC COLUMN COOLS. LOW TEMPERATURES SHOULD OCCUR
BETWEEN 7 AND 9 AM THURSDAY MORNING.
THURSDAY...THERE MAY OR MAY NOT BE SOME LINGERING DRIZZLE ACROSS THE
EASTERN CWFA EARLY IN THE MORNING. CONDENSATION PRESSURE DEFICITS
CONTINUE TO RISE AND NO FORCING IS PRESENT. HOWEVER...FORECAST
SOUNDINGS DO SHOW CONSIDERABLE DRYING ABOVE THE LOW CLOUDS SO SOME
DRIZZLE MAY BE POSSIBLE. CLEARING WILL BE SLOW TO OCCUR DURING THE
MORNING. AS HIGH PRESSURE BEGINS BUILDING IN BY MID DAY A GENERAL
CLEARING OF SKIES SHOULD BE SEEN FROM WEST TO EAST DURING THE
AFTERNOON. MAX TEMPERATURES WILL OCCUR BETWEEN 7 AND 9 AM THURSDAY
MORNING WITH TEMPERATURES SLOWLY FALLING THROUGH THE DAY.
08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...THE LONG TERM
BEGINS WITH A BRIEF COOL DOWN IN THE WAKE OF OUR CURRENT
STORM...THEN AFTER ABOUT 48 HOURS OF NORTHWEST FLOW...WE BEGIN TO
TREND TOWARD ANOTHER POTENTIAL SIGNIFICANT STORM SYSTEM FOR SUNDAY
NIGHT THROUGH TUESDAY.
MOISTURE WILL BE STARVED...BUT SOME POSSIBLE FLURRIES OR BRIEF LIGHT
SNOW COULD OCCUR SATURDAY AFTERNOON IN THE FAR NORTH AS SHEARED OUT
SHORT WAVE ARRIVES FROM THE NORTHWEST. THIS LOOKS TO MAIN PRODUCE
MID CLOUDS DURING THE AFTERNOON AND EVENING HOURS SATURDAY.
TEMPERATURES WILL BE COOL...BUT NOT COLD. WITH LOWS IN THE LOWER TO
MID 20S...AND HIGHS GENERALLY IN THE LOWER TO UPPER 30S.
SUNDAY...THERE BEGINS TO BE ANOTHER CHANGE TOWARD AN ACTIVE STORM
SYSTEM. THERE ARE MAJOR DIFFERENCES IN THE POSITION OF A NORTHWEST
FLOW WAVE THAT MAKES LANDFALL ON EITHER THE SOUTHWEST CANADIAN
COAST/BRITISH COLUMBIA...OR NORTHWESTERN CONUS. THIS SMALL
DIFFERENCE IN MODELS GREATLY INFLUENCED THE AMOUNT OF PHASING OF THE
UPPER LOW WHICH SHOULD BE CUT OFF IN THE SOUTHWEST CONUS AT THAT
TIME. THE UKMET...GEM...AND ECMWF CONTINUE TO SHOW THE NORTHWEST
FLOW WAVE HITTING THE WA/OR COASTLINE THEN DRAWING THE CUT OFF LOW
NORTHEAST SUNDAY NIGHT. THE GFS MAKES A MORE NORTHERLY ENTRY INTO
CENTRAL BRITISH COLUMBIA WITH THE NORTHWESTERN SHORT
WAVE...THUS...IT IS DELAYED BY 24 HOURS ON PHASING WITH THE LOW IN
THE SOUTHWEST...AND LESS SO AT THAT. THUS...FOR THAT REASON
ALONE...THE GFS REMAINS FAR SOUTH OF OTHER GLOBAL MODELS...AS WELL
AS SLOWER. THE CURRENT STORM OVERHEAD WAS ALSO FORECAST BY THE GFS
TO BE FARTHER SOUTH WHEN IT WAS OUT IN THIS DAY 6 PERIOD FOR SIMILAR
REASONS...AND THEREFORE WHEN COMBINED WITH THE FACT THAT THERE IS
LITTLE OR NO SNOW COVER IN THE MIDWEST AND THERE IS NO ARCTIC AIR IN
PLACE TO KEEP A SYSTEM SOUTH...I BELIEVE IN A MORE PHASED NORTHERLY
SOLUTION. THIS POTENTIAL STORM LOOKS TO HAVE ANOTHER OPEN GULF...AND
MODEST TO STRONG UPPER FORCING. THUS...SHOULD IT OCCUR...ANOTHER
ROUND OF MODERATE RAIN IS LIKELY.
SNOW MAY OCCUR ON THE BACKSIDE PENDING THE SPEED OF THE SYSTEM AND
ABILITY TO DYNAMICALLY COOL THE ATMOSPHERE. THERE IS LITTLE
CONFIDENCE IN THAT PROCESS AT THIS TIME...BUT ENOUGH TO WARRANT
INCLUDING A RAIN OR SNOW FORECAST FOR THE NORTHWEST HALF MONDAY
NIGHT. TUESDAY MAY SEE SNOW...BUT THAT WILL DEPEND GREATLY ON THIS
SYSTEM REMAINING CLOSED AT MID LEVELS. WEDNESDAY OF NEXT WEEK
APPEARS DRY AND SEASONALLY COOL.
ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
600 PM CST WED DEC 14 2011
.AVIATION...
LIFR TO IFR CONDITIONS WITH DRIZZLE OR LIGHT RAIN WILL CONTINUE AS A
LOW PRESSURE SYSTEM PASSES NORTH OF THE TERMINALS. A COLD FRONT
WILL MOVE THROUGH AROUND 06Z SWITCHING WINDS FROM SOUTH TO WEST.
THERE MAY BE A SMALL IMPROVEMENT IN CIGS OR VISBYS AFTER COLD
FRONT PASSAGE...BUT STILL NO BETTER THAN IFR. AFTER 15Z
THURSDAY THE 15TH STRONG SUBSIDENCE WILL WORK IN HELPING TO
IMPROVE CONDITIONS TO AT LEAST MVFR WITH STRONG NORTHWEST WINDS OF
15 GUST 20-25KTS. BY 21Z IN THE AFTERNOON ALL SITES SHOULD BE VFR.
..LE..
&&
.PREV DISCUSSION... /ISSUED 319 PM CST WED DEC 14 2011/
SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB WARM FRONT FROM SOUTH DAKOTA INTO
SOUTHERN WISCONSIN. A LLJ RAN FROM THE WESTERN GREAT LAKES TO NORTH
TEXAS WITH THE STRONG CORE OF 50-55 KNOTS FROM EASTERN KANSAS INTO
NORTH TEXAS. A STRONG MOISTURE FEED RAN FROM THE GULF COAST INTO THE
WESTERN GREAT LAKES. RADAR TRENDS SHOW THE CONVECTION AND
THUNDERSTORMS HAVE SHIFTED INTO EASTERN ILLINOIS WITH PRECIPITATION
INTENSITY DECREASING ACROSS IOWA AND MISSOURI.
18Z SFC ANALYSIS HAD A WEAK LOW NEAR KLNK WITH A WARM FRONT ALONG
THE IA/MO BORDER INTO CENTRAL ILLINOIS. A COLD FRONT RAN FROM THE
LOW BACK INTO SOUTHEAST COLORADO. DEW POINTS SOUTH OF THE WARM FRONT
WERE IN THE 50S AND 60S.
SHORT TERM...TONIGHT AND THURSDAY...
THE RUC HAS BEEN DOING A REASONABLE JOB OF HANDLING THE IMMEDIATE
SHORT TERM AND THE TRENDS OF THE RUC WERE FOLLOWED FOR INPUT TONIGHT.
THE LIFT TOOL INDICATES THE THREAT OF THUNDER IS NOW OVER WITH THE
PASSAGE OF A STRONG VORT MAX. OVERALL PRECIPITATION INTENSITY WILL
NOW BE LIGHT DURING THE EVENING HOURS WITH EVERYTHING TRANSITIONING
TO MORE DRIZZLE WITH TIME. THUS DRIZZLE WITH SOME RAIN WILL BE SEEN
DURING THE EVENING HOURS ALONG WITH PATCHY FOG. AFTER MIDNIGHT...
CONDENSATION PRESSURE DEFICITS SLOWLY RISE IN THE WEST WITH THE
BETTER FORCING SHIFTING EAST OF THE MISSISSIPPI. THE RUC DOES SHOW
ANOTHER ROUND OF FORCING ARRIVING AROUND MIDNIGHT IN THE WESTERN
CWFA. THUS WILL CONTINUE THE DRIZZLE WITH OVERALL LOWER CHANCES OF
RAIN. PATCHY FOG WILL STILL BE AN ISSUE AFTER MIDNIGHT.
THE OVERALL DENSE FOG IS PATCHY IN NATURE AND GENERALLY CONFINED TO
THE HWY 20 CORRIDOR. THE MORE WIDESPREAD AND LIKELY DENSE FOG SHOULD
BE SEEN ACROSS WISCONSIN AND MINNESOTA WHERE THE SFC LOW TRACKS.
THE COLD FRONT WILL MOVE THROUGH THE CWFA AFTER MIDNIGHT. WINDS
SHOULD REMAIN UP WHICH WILL KEEP THE FOG FROM GETTING TOO DENSE AS
THE OVERALL ATMOSPHERIC COLUMN COOLS. LOW TEMPERATURES SHOULD OCCUR
BETWEEN 7 AND 9 AM THURSDAY MORNING.
THURSDAY...THERE MAY OR MAY NOT BE SOME LINGERING DRIZZLE ACROSS THE
EASTERN CWFA EARLY IN THE MORNING. CONDENSATION PRESSURE DEFICITS
CONTINUE TO RISE AND NO FORCING IS PRESENT. HOWEVER...FORECAST
SOUNDINGS DO SHOW CONSIDERABLE DRYING ABOVE THE LOW CLOUDS SO SOME
DRIZZLE MAY BE POSSIBLE. CLEARING WILL BE SLOW TO OCCUR DURING THE
MORNING. AS HIGH PRESSURE BEGINS BUILDING IN BY MID DAY A GENERAL
CLEARING OF SKIES SHOULD BE SEEN FROM WEST TO EAST DURING THE
AFTERNOON. MAX TEMPERATURES WILL OCCUR BETWEEN 7 AND 9 AM THURSDAY
MORNING WITH TEMPERATURES SLOWLY FALLING THROUGH THE DAY.
.08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...THE LONG TERM
BEGINS WITH A BRIEF COOL DOWN IN THE WAKE OF OUR CURRENT
STORM...THEN AFTER ABOUT 48 HOURS OF NORTHWEST FLOW...WE BEGIN TO
TREND TOWARD ANOTHER POTENTIAL SIGNIFICANT STORM SYSTEM FOR SUNDAY
NIGHT THROUGH TUESDAY.
MOISTURE WILL BE STARVED...BUT SOME POSSIBLE FLURRIES OR BRIEF LIGHT
SNOW COULD OCCUR SATURDAY AFTERNOON IN THE FAR NORTH AS SHEARED OUT
SHORT WAVE ARRIVES FROM THE NORTHWEST. THIS LOOKS TO MAIN PRODUCE
MID CLOUDS DURING THE AFTERNOON AND EVENING HOURS SATURDAY.
TEMPERATURES WILL BE COOL...BUT NOT COLD. WITH LOWS IN THE LOWER TO
MID 20S...AND HIGHS GENERALLY IN THE LOWER TO UPPER 30S.
SUNDAY...THERE BEGINS TO BE ANOTHER CHANGE TOWARD AN ACTIVE STORM
SYSTEM. THERE ARE MAJOR DIFFERENCES IN THE POSITION OF A NORTHWEST
FLOW WAVE THAT MAKES LANDFALL ON EITHER THE SOUTHWEST CANADIAN
COAST/BRITISH COLUMBIA...OR NORTHWESTERN CONUS. THIS SMALL
DIFFERENCE IN MODELS GREATLY INFLUENCED THE AMOUNT OF PHASING OF THE
UPPER LOW WHICH SHOULD BE CUT OFF IN THE SOUTHWEST CONUS AT THAT
TIME. THE UKMET...GEM...AND ECMWF CONTINUE TO SHOW THE NORTHWEST
FLOW WAVE HITTING THE WA/OR COASTLINE THEN DRAWING THE CUT OFF LOW
NORTHEAST SUNDAY NIGHT. THE GFS MAKES A MORE NORTHERLY ENTRY INTO
CENTRAL BRITISH COLUMBIA WITH THE NORTHWESTERN SHORT
WAVE...THUS...IT IS DELAYED BY 24 HOURS ON PHASING WITH THE LOW IN
THE SOUTHWEST...AND LESS SO AT THAT. THUS...FOR THAT REASON
ALONE...THE GFS REMAINS FAR SOUTH OF OTHER GLOBAL MODELS...AS WELL
AS SLOWER. THE CURRENT STORM OVERHEAD WAS ALSO FORECAST BY THE GFS
TO BE FARTHER SOUTH WHEN IT WAS OUT IN THIS DAY 6 PERIOD FOR SIMILAR
REASONS...AND THEREFORE WHEN COMBINED WITH THE FACT THAT THERE IS
LITTLE OR NO SNOW COVER IN THE MIDWEST AND THERE IS NO ARCTIC AIR IN
PLACE TO KEEP A SYSTEM SOUTH...I BELIEVE IN A MORE PHASED NORTHERLY
SOLUTION. THIS POTENTIAL STORM LOOKS TO HAVE ANOTHER OPEN GULF...AND
MODEST TO STRONG UPPER FORCING. THUS...SHOULD IT OCCUR...ANOTHER
ROUND OF MODERATE RAIN IS LIKELY.
SNOW MAY OCCUR ON THE BACKSIDE PENDING THE SPEED OF THE SYSTEM AND
ABILITY TO DYNAMICALLY COOL THE ATMOSPHERE. THERE IS LITTLE
CONFIDENCE IN THAT PROCESS AT THIS TIME...BUT ENOUGH TO WARRANT
INCLUDING A RAIN OR SNOW FORECAST FOR THE NORTHWEST HALF MONDAY
NIGHT. TUESDAY MAY SEE SNOW...BUT THAT WILL DEPEND GREATLY ON THIS
SYSTEM REMAINING CLOSED AT MID LEVELS. WEDNESDAY OF NEXT WEEK
APPEARS DRY AND SEASONALLY COOL.
.ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1116 PM CST MON DEC 12 2011
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
MOIST UPSLOPE FLOW CONTINUE ACROSS SOUTHWEST KANSAS WITH
VISIBILITIES ALREADY FALLING TO 1/4 MILE AT GCK AND DDC. THIS AREA
WAS WHERE MOISTURE APPEARS TO BE POOLING NEAR A SURFACE BOUNDARY
WHICH EXTENDED FROM NEAR SYRACUSE TO SCOTT CITY TO WAKEENEY. THE
RUC AND NAM WERE IN GOOD AGREEMENT WITH THE LOW LEVEL MOISTURE IN
THIS AREA INCREASING AND DEEPENING THROUGH THE PREDAWN HOURS. AS A
RESULT THE DEPTH OF THIS MOIST LAYER IS EXPECTED TO EXCEEDS 1KM
AFTER 09Z SO IN ADDITION TO THE FOG SOME DRIZZLE CAN ALSO BE
EXPECTED. CEILINGS OVER THE NEXT 12-15 HOURS ARE NOT EXPECTED TO
IMPROVE MUCH BASED ON THE NAM BUFR SOUNDINGS BUT VSBYS SHOULD
START TO IMPROVE BY 15Z.
&&
.PREV DISCUSSION... /ISSUED 725 PM CST MON DEC 12 2011/
UPDATE...
THE LATEST 00 UTC KDDC SOUNDING IS INDICATING A NEARLY SATURATED
LAYER FROM NEAR THE SURFACE TO 5,000FT, ASSOCIATED WITH THE STRATUS
ACROSS THE AREA THIS EVENING. ABOVE THAT IS A TREMENDOUSLY DRY AND
DEEP LAYER FROM AROUND 875 MB THROUGH THE MIDDLE TROPOSPHERE. THE
KDDC RADAR ECHOES THAT HAVE BEEN MOVING ACROSS THE WESTERN AND
SOUTHWEST COUNTIES THIS EVENING ARE PRIMARILY ELEVATED ECHOS WITH NO
PRECIPITATION. WE`VE REMOVED POPS AND RAIN SHOWERS/DRIZZLE
ALTOGETHER FOR THIS EVENING, AND RAMPED UP POPS ACROSS THE
SOUTHEAST 1/2 OF THE FORECAST AREA AFTER MIDNIGHT TO CLOSER FOLLOW
THE HOURLY RAPID REFRESH RUC MODEL. ADDITIONALLY, AREAS OF FOG HAVE
BEEN INTRODUCED ON A WIDER SCALE GIVEN THE CURRENT NAM AND HRRR`S
VSBYS AND TRENDS WITHING THE SURFACE MOISTURE CONVERGENCE ZONE. -RUSSELL
PREV DISCUSSION... /ISSUED 319 PM CST MON DEC 12 2011/
DISCUSSION...
DAYS 1-2...
THE UPPER LEVEL LOW CURRENTLY ACROSS SOUTHERN CALIFORNIA WILL START
TO EJECT EAST NORTHEAST ACROSS THE FOUR CORNERS REGION TOMORROW AND
ACROSS THE CENTRAL PLAINS BY THURSDAY MORNING. A STRONG UPPER LEVEL
JET WILL ACCOMPANY THIS SYSTEM ENHANCING LIFT ACROSS OUR CWA TONIGHT
INTO WEDNESDAY MORNING. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
BE FOUND ACROSS THE EASTERN THIRD OF THE UNITED STATES. AT THE
SURFACE...AN AREA OF HIGH PRESSURE WILL BE FOUND ACROSS THE GULF OF
MEXICO AND CONTINUE TO BRING LOWER TO MID LEVEL MOISTURE NORTH INTO
OUR AREA. A SURFACE COLD FRONT IS ANTICIPATED TO CONTINUE TO MOVE
SOUTH ACROSS KANSAS THIS AFTERNOON AND STALL OUT ACROSS OUR CWA THIS
EVENING. THIS FRONTAL BOUNDARY WILL THEN MOVE NORTHWARD OVERNIGHT
AND BE POSITIONED ACROSS THE KS/NE BORDER BY TOMORROW MORNING. RAIN
CHANCES INCREASE OVERNIGHT AND LIGHT RAIN IS POSSIBLE ACROSS
SOUTHEAST PORTIONS OF THE CWA BY MIDNIGHT SPREADING ACROSS THE
REMAINDER OF THE CWA BY TOMORROW MORNING. PATCHY FOG IS ALSO
POSSIBLE OVERNIGHT BUT SHOULD DISSIPATE BY MORNING. LAST, THERE
COULD BE A FEW AREAS THAT EXPERIENCE LIGHT FREEZING RAIN ACROSS
HAMILTON, KEARNY, SCOTT, AND TREGO COUNTIES AFTER MIDNIGHT BUT NO
ACCUMULATION OF ICE IS EXPECTED AS SURFACE TEMPERATURES WILL BE
ABOVE FREEZING.
MOISTURE CONTINUES TO ADVECT NORTHWARD ACROSS THE AREA TOMORROW
AHEAD OF THE UPPER LEVEL TROUGH ALLOWING CLOUDY SKIES AND RAIN
CHANCES TO CONTINUE THROUGHOUT THE DAY. RAIN CHANCES RANGE FROM 50
PERCENT IN THE WEST TO OVER 70 PERCENT IN THE EAST. AN AREA OF LOW
PRESSURE IS EXPECTED TO MOVE FROM NORTHEASTERN NEW MEXICO TOMORROW
AFTERNOON AND SHIFT EAST INTO SOUTHEAST NEBRASKA BY WEDNESDAY
AFTERNOON. THIS WILL PUSH A COLD FRONT THROUGH THE AREA TOMORROW
NIGHT INTO WEDNESDAY MORNING. I HAVE KEPT IN THE WORDING OF ISOLATED
THUNDER ACROSS EASTERN PORTIONS OF THE CWA TOMORROW NIGHT ENDING IN
THE LATE MORNING AS THE COLD FRONT MOVES INTO WICHITA`S WFO. POPS
DECREASE FROM WEST TO EAST TOMORROW NIGHT INTO WEDNESDAY AND BELOW
15 PERCENT ACROSS THE ENTIRE CWA BY WEDNESDAY AFTERNOON. CLOUDS WILL
ALSO BE ON THE DECREASE AS THE SYSTEM EXITS OFF TO THE EAST LEAVING
PARTLY CLOUDY SKIES BY WEDNESDAY EVENING.
LOWS TONIGHT WILL RANGE FROM THE LOWER 30S IN THE NORTHWEST TO LOWER
40S IN THE SOUTHEAST WITH HIGHS TOMORROW WILL RISING INTO THE MID TO
UPPER 40S. OVERNIGHT LOWS TOMORROW NIGHT COULD ACTUALLY CLIMB ABOVE
TUESDAYS HIGHS DEPENDING ON DEWPOINTS. I WILL CONTINUE NEARLY STEADY
TEMPERATURES IN THE 40S OVERNIGHT WITH TH EXCEPTION OF NORTHEAST
PORTIONS OF THE CWA WHERE LOWS COULD DROP INTO THE UPPER 30S. HIGHS
ON WEDNESDAY ARE ANTICIPATED TO RANGE FROM THE LOWER 50S IN THE
NORTHWEST TO NEAR 60 IN THE SOUTHEAST.
DAYS 3-7...
THE MEDIUM RANGE MODELS SHOW A SECONDARY SHORTWAVE TROUGH LIFTING
OUT OF THE DESERT SOUTHWEST AND NORTHERN MEXICO ACROSS THE SOUTHERN
PLAINS LATER THIS WEEK. THE ENERGY WITH THIS WAVE IS PRETTY FAR
SOUTH AND WITH ALL THE BEST LOW LEVEL MOISTURE BEING SHUNTED SOUTH
BY THE MIDWEEK SYSTEM...THE DRY FORECAST LOOKS GOOD. THE MODELS SHOW
ANOTHER ANTICYCLONIC WAVE BREAK OCCURRING LATE THURSDAY AND THURSDAY
NIGHT. A SHORTWAVE TROUGH NOW SOUTHWEST OF THE ALEUTIAN ISLANDS IS
FORECAST TO TOP THE EASTERN PACIFIC RIDGE AND DIG SOUTH ACROSS THE
WESTERN STATES. THE ECMWF AND CANADIAN MODELS HAVE BEEN FAIRLY
CONSISTENT WITH THE TRACK AND TIMING OF THIS SYSTEM AS IT CLOSES OFF
AND HANGS BACK IN THE SOUTHWEST BEFORE LIFTING OUT TOWARD THE
CENTRAL/SOUTHERN PLAINS LATE NEXT WEEKEND. THE GFS HAS TENDED TO BE
MORE PROGRESSIVE AS IT TENDS TO DO. YESTERDAYS GFS ENSEMBLE MEMBERS
WERE MOSTLY SLOWER THAN THE OPERATIONAL RUN. TODAYS GFS ENSEMBLE
MEMBERS WERE STILL A LITTLE SCATTERED BUT MOSTLY KEEP THE SYSTEM
SLOWER LIKE THE OTHER MODELS. THE 12Z GFS OPERATIONAL MODEL NOW
APPEARS TO BE IN BETTER AGREEMENT WITH THE OTHERS.
GIVEN THE LATEST MODEL OUTPUT...THINK THAT THE ONSET OF ANY CHANCES
FOR PRECIPITATION WILL NOT OCCUR UNTIL SUNDAY AT THE EARLIEST AND
MORE LIKELY SUNDAY NIGHT IF THE SLOWER MODEL SOLUTION PANS OUT.
THERE IS SOME UNCERTAINTY THIS FAR OUT AS TO WHAT PRECIPITATION TYPE
WILL BE AS THE GFS SHOWS ABOVE FREEZING TEMPERATURES FOR MOST OF THE
EVENT. SOME DYNAMIC COOLING COULD RESULT IN A RAIN/SNOW MIX OVER TO
SNOW AND WILL SHOW THAT IN THE GRIDS ROUGHLY NORTHWEST OF A MEADE TO
LARNED LINE.
WITH NO SIGNIFICANT COLD AIR INTRUSIONS INDICATED BY THE
MODELS...TEMPERATURES SHOULD STAY FAIRLY SEASONAL FOR DECEMBER.
FOR WEEK TWO WILL MAINTAIN THE NEAR NORMAL TEMPERATURES AND
PRECIPITATION AS THE MODELS ARE INDICATING THE POSSIBILITY FOR
ANOTHER WAVE DROPPING INTO THE SOUTHWEST AND CLOSING OFF AROUND
DECEMBER 21ST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 47 45 53 / 60 60 60 30
GCK 35 46 44 50 / 50 60 60 20
EHA 37 47 42 51 / 50 60 60 10
LBL 39 49 47 53 / 50 60 60 20
HYS 34 45 43 51 / 40 60 60 50
P28 41 49 47 60 / 70 80 80 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CST /7 AM MST/ TUESDAY FOR KSZ030-
043>045-061>064-074>078.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 PM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE EAST OF THE AREA TONIGHT, KEEPING
THE AREA MOSTLY DRY AND TEMPERATURES SEASONABLE. A WARM FRONT
WILL LIFT INTO THE AREA ON WEDNESDAY AND BRING THE CHANCE OF
SHOWERS. SHOWERS WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD
FRONT CROSSES THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW. AT THE SURFACE, A 1031MB HIGH
IS CENTERED ACROSS WESTERN PA. DESPITE HIGH PRESSURE IN PLACE,
WEAK ISENTROPIC LIFT AT 295K ALONG WITH WARM AIR ADVECTION HAS
INSTIGATED A FEW SHOWERS ACROSS CENTRAL OHIO.
TONIGHT...AN AREA OF ISENTROPIC LIFT AHEAD OF A WARM FRONT WILL PUSH
EASTWARD INTO THE AREA OVERNIGHT. THIS WILL ALLOW FOR THE CHANCE
OF SHOWERS BY DAWN FOR AREAS EAST OF PITTSBURGH WITH A SCHC FOR
AREAS WEST. FOR TEMPERATURES OVERNIGHT, FORECAST IS CLOSEST TO THE
LAMP, A FEW DEGREES WARMER THAN A MAV/MET BLEND. LOWS WILL RANGE
FROM THE LOWER 30S IN WESTERN PA TO THE MID 30S IN EASTERN OHIO
AND NORTH-CENTRAL WV.
FOR PRECIP TYPE, 12Z OPERATIONAL MODEL RUNS INDICATE A WARMING
LOW-LEVEL THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING)
ALLOWING FOR ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH
SURFACE TEMPS A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE
LEANED AGAINST A MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR
ALOFT PREVENTING DENDRITIC GROWTH AND SATURATION LIMITED TO THE
LOWER LEVELS. WILL NEED TO MONITOR SURFACE TEMPS NEAR FREEZING
ACROSS THE EASTERN RIDGES FOR THE POTENTIAL OF FREEZING RAIN IF
PRECIP CAN ADVANCE THAT FAR EAST. WITH TDS IN THE UPPER TEENS TO
LOWER 20S, WET BULB EFFECT COULD BRING TEMPS DOWN BRIEFLY BELOW
FREEZING IF PRECIP CAN MAKE ADVANCE THAT FAR EAST. HOWEVER,
CONFIDENCE IS TOO LOW TO INCLUDE SCHC OF FZRA IN ANY GRIDS AT
THIS TIME.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A SURFACE LOW WILL LIFT NORTHEASTWARD FROM THE PLAINS INTO THE
UPPER MIDWEST. THIS SYSTEM WILL PUSH A WARM FRONT INTO THE AREA ON
WEDNESDAY. THERE IS GFS/ECMWF AGREEMENT IN ITS TIMING AND
EASTWARD EXTENT THROUGH THE UPPER OHIO VALLEY. THUS, CHANCE POPS
ARE FORECAST ACROSS THE AREA AS SHOWERS MOVE THROUGH. WARM AIR
ADVECTION WILL INCREASE AS THE FRONT PUSHES NORTH OF THE AREA
TOMORROW. THIS WILL ALLOW FOR TEMPERATURES TO WARM TO AROUND 10
DEGREES ABOVE NORMAL.
WEDNESDAY NIGHT INTO THURSDAY...THE MODELS ARE IN REASONABLE
AGREEMENT THAT A DRY SLOT WILL PUSH INTO THE AREA WITH WARM AIR
ADVECTION AS A COLD FRONT APPROACHES FROM THE WEST WED NIGHT. WITH A
BREAK IN PRECIP EXPECTED, DRY OR SCHC POPS ARE FORECAST ACROSS
MOST OF THE AREA. FORCING FROM A COLD FRONT WILL SUPPORT PRECIP
FOR THE AREA WITH CATEGORICAL POPS REACHING THE PITTSBURGH METRO
BY DAWN ON THURSDAY. MORE PERSISTENT RAINFALL IS EXPECTED THROUGH
MUCH OF THE DAY THURSDAY AS THE FRONT SLOWLY PROGRESSES ACROSS THE
OHIO VALLEY. FOR QPF WITH THIS EVENT, A HALF OF AN INCH TO AN INCH
OF RAIN IS EXPECTED ACROSS THE AREA. ONGOING WARM AIR
ADVECTION WILL ALLOW FOR TEMPS TO BE 15 TO 20 DEGREES ABOVE
NORMAL.
THURSDAY NIGHT AND FRIDAY...THE FRONT WILL CROSS THE AREA THURSDAY
NIGHT WITH A LOW-LEVEL NORTHWESTERLY FLOW AND HIGH PRESSURE
BUILDING IN FROM THE WEST IN ITS WAKE. 850MB AND LAKE ERIE TEMP
DIFFERENTIAL WILL BE SUFFICIENT TO SUPORT A FEW LAKE EFFECT SNOW
SHOWERS IN THE WAKE OF THIS SYSTEM ON FRIDAY. TEMPS ON FRIDAY WILL
BE CLOSER TO SEASONAL NORMALS AS THE ARCTIC AIR WORKS INTO THE REGION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
PER MORE HPC-PREFERRED RECENT ECMWF MODEL OUTPUT, EXPECT POST SYSTEM
CHILL DOWN TO CAUSE SCATTERED SNOW SHOWERS ACROSS NORTHWEST
PENNSYLVANIA AND POSSIBLY THE MOUNTAINS THIS WEEKEND, AND MOSTLY
CLOUDY SKIES ELSEWHERE.
A LOW PRESSURE SYSTEM, COMING NORTHEAST FROM TEXAS, MAY MAINTAIN
CLOUDS ACROSS THE AREA MONDAY AND PROVIDE MIXED PRECIPITATION
TUESDAY.
HPC GUIDANCE, GFS MOS AND NAEFS MEDIAN VALUES CONCUR THAT
TEMPERATURES SATURDAY CAN BE ABOUT 5 DEGREES COLDER THAN NORMAL.
TEMPERATURES SHOULD THEN MODERATE TO VALUES UP TO 5 DEGREES WARMER
THAN NORMAL BY MONDAY AND TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
THROUGH 09Z WEDNESDAY, EXPECT VFR CONDITIONS. WITH NO LOWER THAN
ALTOCUMULUS CEILINGS. AFTER 09Z WEDNESDAY, VFR SHOULD STILL BE
PREVALENT. ALTHOUGH PASSING WARM FRONT SHOULD INDUCE LOWER CEILINGS,
IN THE STRATOCUMULUS RANGE/040-060 HFT. RAIN SHOWERS WILL BE
POSSIBLE, BUT FORESEE ONLY A SMALL CHANCE OF MVFR VISIBILITIES.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
WEDNESDAY NIGHT, EXPECT PREVALENT VFR. THURSDAY INTO THURSDAY NIGHT,
EXPECT A WIDE BAND OF COLD FRONTAL SHOWERS WITH A PERIOD OF IFR
RESTRICTIONS LIKELY. FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL
MVFR STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, LINGERING MVFR
STRATOCUMULUS POSSIBLE MAINLY NORTH AND MOUNTAINS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
139 PM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE ACROSS THE AREA TODAY, KEEPING THE
AREA MOSTLY DRY AND TEMPERATURES SEASONABLE. A WARM FRONT WILL
LIFT INTO THE AREA ON WEDNESDAY AND BRING THE CHANCE OF SHOWERS.
SHOWERS WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD FRONT
CROSSES THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
18Z ENHANCED SHORT TERM FORECAST HAS BEEN TO ACCOUNT FOR INITIAL
DIMINISHING CLOUD COVERAGE ACROSS WESTERN PA AND TO ADD SCHC POPS
FOR PORTIONS OF EASTERN OHIO.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW. AT THE SURFACE, A 1032MB HIGH
IS CENTERED ACROSS WESTERN PA. DESPITE HIGH PRESSURE IN PLACE,
WEAK ISENTROPIC LIFT AT 295K ALONG WITH WARM AIR ADVECTION HAS
INSTIGATED A FEW SHOWERS ACROSS CENTRAL OHIO.
TODAY...THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD ACROSS WESTERN
PENNSYLVANIA. THIS WILL ALLOW FOR MOSTLY A DRY DAY. THE EXCEPTION
WILL BE THE SCHC IN EASTERN OHIO AS WEAK ISENTROPIC LIFT MOVES
INTO THIS AREA. WEAK WARM AIR ADVECTION WILL OCCUR TODAY WITH 850
TEMPS WARMING TO 0-2C ACROSS THE AREA. WITH THIS IN MIND, HIGH
TEMPS ARE A MAV/MET BLEND, RANGING FROM THE UPPER 40S ACROSS
NORTH-CENTRAL WV AND EASTERN OHIO TO THE LOWER 40S ACROSS THE
EASTERN RIDGES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WARM FRONT WILL PASS THROUGH WEDNESDAY MORNING. THERE ARE STILL
DISCREPANCIES BETWEEN OP MODELS ON THE AMOUNT OF PRECIPITATION AND
ITS EASTWARD EXTENT WITH THE FRONT. A COMPROMISE OF THE SREF, NAM
AND NMM-WRF, INDICATES THAT MOST OF THE RAIN CHANCE WILL BE OVER
OHIO AND EVENTUALLY NORTHERN PA.
RECENT OPERATIONAL MODEL RUNS INDICATE A WARMING LOW- LEVEL
THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING) ALLOWING FOR
ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH SURFACE TEMPS
A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE LEANED AGAINST A
MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR ALOFT PREVENTING
DENDRITIC GROWTH AND SATURATION LIMITED TO THE LOWER LEVELS. WILL
NEED TO MONITOR SURFACE TEMPS NEAR FREEZING ACROSS THE EASTERN
RIDGES FOR THE POTENTIAL OF FREEZING RAIN IF PRECIP CAN ADVANCE
THAT FAR EAST. CONFIDENCE IS TOO LOW TO INCLUDE SCHC OF FZRA IN ANY
GRIDS AT THIS TIME.
THE WARM FRONT PASSES TO THE NORTH WED AFTERNOON. THIS WILL PUT
THE AREA IN THE WARM SECTOR AND ALSO PROVIDE A BREAK IN THE RAIN
AHEAD OF THE APPROACHING COLD FRONT.
COLD FRONT WILL MOVE THROUGH LATE THURSDAY. IT LOOKS LIKE A
WIDESPREAD RAIN EVENT FOR THE AREA, BEGINNING THU MORNING AND
CONTINUING INTO THE EVENING HOURS. STRONG MID-LEVEL JET WILL PUMP
PLENTY OF MOISTURE INTO THE REGION AHEAD OF THE SFC FRONT.
A STRONG SOUTHERLY LL FLOW WILL PUSH TEMPS WILL ABOVE NORMAL ON
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BRIEF PERIOD OF LES IS POSSIBLE LATE THU/EARLY FRIDAY WITH THE
STRONG CAA BEHIND THE FRONT.
A SFC WAVE, OVER THE SE US, WILL DEVELOP ALONG THE COLD FRONT
FRIDAY. LATEST MODEL DATA IS KEEPING THIS WAVE SOUTH OF THE AREA.
HOWEVER, IT IS POSSIBLE THAT SOUTHERN LOCATIONS COULD SEE SOME
LIGHT PRECIP FRIDAY NIGHT.
HIGH PRESSURE WILL BUILD IN, KEEPING THE REMAINDER OF THE LONG
TERM DRY.
&&
.AVIATION /19Z TUESDAY THROUGH SATURDAY/...
THROUGH TONIGHT, EXPECT VFR CONDITIONS. WITH NO LOWER THAN
ALTOCUMULUS CEILINGS. DURING DAYTIME WEDNESDAY, EXPECT VFR TO
CONTINUE TO BE PREVALENT. PASSING WARM FRONT SHOULD INDUCE CEILINGS
MORE IN THE STRATOCUMULUS RANGE/040-060 HFT. RAIN SHOWERS WILL BE
POSSIBLE, BUT FORESEE ONLY A SMALL CHANCE OF MVFR VISIBILITIES.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT, EXPECT PREVALENT VFR. THURSDAY INTO THURSDAY NIGHT,
EXPECT A WIDE BAND OF COLD FRONTAL SHOWERS WITH A PERIOD OF IFR
RESTRICTIONS LIKELY. FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL
MVFR STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, VFR PREVALENT,
EXCEPT POSSIBLE LINGERING MVFR STRATOCUMULUS NORTH AND MOUNTAINS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1029 AM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE ACROSS THE AREA TODAY, KEEPING THE
AREA DRY AND TEMPERATURES SEASONABLE. A WARM FRONT WILL LIFT INTO
THE AREA ON WEDNESDAY AND BRING THE CHANCE OF SHOWERS. SHOWERS
WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD FRONT CROSSES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
15Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO INCREASE HIGH
TEMPS TODAY 2-3 DEGREES. IN ADDITION, PRECIPITATION NEAR DAWN
TOMORROW HAS BEEN CHANGED FROM A MIX OF RAIN AND SNOW TO ALL RAIN.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW WITH 700MB MOISTURE ADVECTING
INTO THE AREA. THIS HAS ALLOWED FOR INCREASING CLOUDINESS AS THE
MID-DECK MOVES INTO THE AREA. AT THE SURFACE, A 1031MB HIGH IS
CENTERED ACROSS OHIO.
TODAY...THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD INTO WESTERN
PENNSYLVANIA. THIS WILL ALLOW FOR A DRY DAY. 700MB MOISTURE
ADVECTING ACROSS THE AREA WILL ALLOW FOR SKY COVERAGE INCREASING
TO MOSTLY CLOUDY INTO THE AFTERNOON. WEAK WARM AIR ADVECTION WILL
OCCUR TODAY WITH 850 TEMPS WARMING TO 0-2C ACROSS THE AREA. WITH
THIS IN MIND, HIGH TEMPS ARE A MAV/MET BLEND, RANGING FROM THE
UPPER 40S ACROSS NORTH-CENTRAL WV AND EASTERN OHIO TO THE LOWER
40S ACROSS THE EASTERN RIDGES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WARM FRONT WILL PASS THROUGH WEDNESDAY MORNING. THERE ARE STILL
DISCREPANCIES BETWEEN OP MODELS ON THE AMOUNT OF PRECIPITATION AND
ITS EASTWARD EXTENT WITH THE FRONT. A COMPROMISE OF THE SREF, NAM
AND NMM-WRF, INDICATES THAT MOST OF THE RAIN CHANCE WILL BE OVER
OHIO AND EVENTUALLY NORTHERN PA.
RECENT OPERATIONAL MODEL RUNS INDICATE A WARMING LOW- LEVEL
THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING) ALLOWING FOR
ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH SURFACE TEMPS
A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE LEANED AGAINST A
MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR ALOFT PREVENTING
DENDRITIC GROWTH AND SATURATION LIMITED TO THE LOWER LEVELS.
THE WARM FRONT PASSES TO THE NORTH WED AFTERNOON. THIS WILL PUT
THE AREA IN THE WARM SECTOR AND ALSO PROVIDE A BREAK IN THE RAIN
AHEAD OF THE APPROACHING COLD FRONT.
COLD FRONT WILL MOVE THROUGH LATE THURSDAY. IT LOOKS LIKE A
WIDESPREAD RAIN EVENT FOR THE AREA, BEGINNING THU MORNING AND
CONTINUING INTO THE EVENING HOURS. STRONG MID-LEVEL JET WILL PUMP
PLENTY OF MOISTURE INTO THE REGION AHEAD OF THE SFC FRONT.
A STRONG SOUTHERLY LL FLOW WILL PUSH TEMPS WILL ABOVE NORMAL ON
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BRIEF PERIOD OF LES IS POSSIBLE LATE THU/EARLY FRIDAY WITH THE
STRONG CAA BEHIND THE FRONT.
A SFC WAVE, OVER THE SE US, WILL DEVELOP ALONG THE COLD FRONT
FRIDAY. LATEST MODEL DATA IS KEEPING THIS WAVE SOUTH OF THE AREA.
HOWEVER, IT IS POSSIBLE THAT SOUTHERN LOCATIONS COULD SEE SOME
LIGHT PRECIP FRIDAY NIGHT.
HIGH PRESSURE WILL BUILD IN, KEEPING THE REMAINDER OF THE LONG
TERM DRY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS, WITH NO LOWER THAN ALTOCUMULUS CEILINGS, THROUGH
TONIGHT.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
DURING DAYTIME WEDNESDAY, A PASSING BAND OF WARM FRONTAL SHOWERS
WITH SHORT-LIVED RESTRICTIONS POSSIBLE. THURSDAY INTO THURSDAY
NIGHT, A WIDER BAND OF COLD FRONTAL SHOWERS WITH RESTRICTIONS MORE
LIKELY. FRIDAY AND SATURDAY, VFR PREVALENT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EST TUE DEC 13 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS
AND A RIDGE OVER THE SE WITH MAINLY ZONAL FLOW FROM THE NRN PLAINS
TO NEW ENGLAND. A VIGOROUS SHORTWAVE TROUGH WAS MOVING THROUGH AZ
WHILE A WEAKER UPSTREAM SHRTWV WAS MOVING INTO SRN SD. AT THE
SFC...A RIDGE EXTENDED FROM NORTHERN QUEBEC TO LAKE SUPERIOR
RESULTING IN WEAK ACYC FLOW OVER THE CWA WITH NO PCPN INDICATED BY
RADAR. WITH THE MILD/MOIST AIRMASS IN PLACE...PATCHY FOG LINGERED
OVER LOCATIONS NEAR THE WI BORDER.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY
TONIGHT...AS THE HIGH SLIDES OFF TO THE SE...SRLY LOW LEVEL FLOW
WILL INCREASE WEAK UPSLOPE FLOW INTO PORTIONS OF WEST AND CENTRAL
UPPER MI MAY BE ENOUGH TO SUPPORT SOME PATCHY -DZ/-FZDZ AFT 06Z EVEN
THOUGH OVERALL LOW LEVEL (925-850 MB) LIFT IS VERY WEAK...PER
NAM/RUC...280K ISENTROPIC PROGS. OTHERWISE...WITH LITTLE DIURNAL
TEMP CHANGE IS EXPECTED OVER THE AREA. AREAS OF FOG...SOME LCLY
DENSE...MAY ALSO THICKEN WITH SLIGHT INCREASE IN MOISTURE ADVECTION.
WEDNESDAY...AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND MOVES
TOWARD THE UPPER MS VALLEY...LOW/MID LEVEL WAA AND MOISTURE
ADVECTION WILL INCREASE. THIS SHOULD BRING AN AREA OF LIGHT PCPN
OVER THE ENTIRE CWA BY AFTERNOON...PER NAM/GFS 290K-295K ISENTROPIC
PROGS. NAM WET-BULB ZERO HEIGHTS SUGGEST THAT THE PCPN SHOULD BE
MAINLY RAIN. HOWEVER...GIVEN LOW LEVEL TEMP PROFILES NEAR 0C OVER
THE INTERIOR WEST...CANNOT RULE OUT SOME SNOW. ANY ACCUMULATIONS
WOULD BE MINIMAL. EVEN THOUGH TEMPS WILL BE ABOVE FREEZING WHEN THE
RAIN ARRIVES...SOME UNTREATED ROADS MAY STILL BE COLD ENOUGH TO
CREATE PATCHY ICY SPOTS.
.LONG TERM /WED NIGHT THROUGH NEXT TUESDAY/...
SHORTWAVE CURRENTLY ROUNDING THE UPPER TROUGH OFF THE COAST OF SRN
CA WILL MOVE TOWARDS THE AREA LATE WED AFTN AND MOVE ACROSS THE AREA
WED EVENING. MODELS FAIRLY CONSISTENT ON THE MAIN ENERGY FROM THE
SHORTWAVE MOVING ACROSS CNTRL/ERN UPPER MI...WHICH WILL GRADUALLY
INTENSIFY THE LOW MOVING FROM IOWA AT 00Z THURS TO SE ONTARIO AT 12Z
THURS. OTHER THAN THE FAST AND NW OUTLIER 12Z NAM...MAIN DIFFERENCES
BETWEEN THE MODELS IS IN THE INTENSITY OF THE LOW. 06-12Z GFS RUNS
ON THE STRONG SIDE AND 00Z ECMWF ON WEAKER SIDE. WILL FOLLOW A BLEND
OF THE TWO SINCE TRACKS ARE SIMILAR AND ONLY MINOR DIFF IN THE
THERMAL PROFILES.
DURING THE EVENING...06 AND 12Z GFS SHOWING STRONG FGEN FROM
H800-400 ACROSS THE CWA. THINK THE BEST FORCING WILL BE ALONG THE
H800-600 FGEN AREA...WHERE THERE IS ABUNDANT MOISTURE AND STRONG
AGEOSTROPHIC UPWARD CIRCULATION. FARTHER NW...APPEARS TO BE A DECENT
H700-500 DRY AIR LAYER...AND DOWNWARD CIRCULATION MAY LIMIT PCPN
FARTHER NW TOWARDS A KIWD TO KCMX LINE. OVER THE E...EXPECT A STRONG
AREA OF H850-700 WAA AND 285-300K SFC ISENTROPIC ASCENT DURING THE
EVENING. THINK THE EXISTING 100 POPS LOOK GOOD AND WILL LEAVE THEM
AS IS. THEN HAVE A GRADUAL LOWERING HEADING OVER THE WEST TOWARDS
HIGH END LIKELY. COULD BE A SHARP CUTOFF TO THE WEST EXTENT OF THE
PCPN OVER THE WRN HALF OF LK SUPERIOR WITH THE FGEN CIRCULATION...SO
TRIED TO SHOW THAT POTENTIAL.
P-TYPE FOR THE WED NIGHT PERIOD IS WHERE THINGS GET TRICKY. BUFKIT
SOUNDINGS FROM THE GFS SHOW AN ISOTHERMAL PROFILE FROM SFC TO
5-6KFT. WITH THAT TYPE OF SITUATION...IT WILL LIKELY BE SNOW WHERE
LAYER IS NEAR 0C AND THEN RA/SN AROUND 1C AND ALL RA AROUND 2-3C.
KCMX MAY BE FAR ENOUGH N AND AWAY FROM THE WARM SURGE TO KEEP PCPN A
RA/SN MIX OR POSSIBLY EVEN ALL SNOW. THEN HEADING S AND E ACROSS THE
CWA...EXPECT A TRANSITION TO ALL RAIN. BIGGEST CONCERN IS GETTING
THAT RA/SN AREA PINNED DOWN AND STILL DON/T HAVE A GREAT FEEL...BUT
IT SHOULD BE OVER THE NW THIRD. FORTUNATELY...THE HEAVIEST QPF WILL
LIKELY BE TO THE SE OF THE UNCERTAIN AREA FOR RA/SN...SO IT SHOULD
LIMIT THE IMPACT IF IT DOES END UP ALL SNOW.
LAST COUPLE OF RUNS OF THE GFS HAVE REALLY BUMPED UP THE QPF IN THE
FGEN LOCATION MOVING ACROSS CNTRL UPPER MI...WITH LIQUID AMOUNTS
EXCEEDING 0.75IN...BUT IT IS LIKELY DUE TO THE MORE WRAPPED UP LOW
SOLN. WILL NOT GO THAT HIGH...BUT WILL NEED TO BE MONITORED IF
STRONGER LOW SOLN PANS OUT. OTHERWISE...EXPECT 0.25 TO 0.4 OF LIQUID
ACROSS THE SE HALF OF THE CWA...MAINLY DURING THE EVENING.
MAIN ENERGY AND DEEPER H700-500 MOISTURE PULLS OUT OVERNIGHT WED AND
HAVE DIMINISHING POPS TO ACCOUNT FOR THAT. P-TYPE IS AGAIN A CONCERN
HEADING INTO THE OVERNIGHT...SINCE THE DEEPER MOISTURE PULLS OUT
BEFORE THE COLDER AIR ARRIVES LATE WED NIGHT INTO THURS. THIS WILL
CUT THE POTENTIAL FOR ICE CRYSTALS IN THE CLOUD WAY DOWN AND LIMIT
THE POTENTIAL FOR SNOW. WITH TEMPERATURES DROPPING TOWARDS FREEZING
OVER THE WEST TOWARDS 12Z THURS...DID KEEP A MENTION OF -FZRA IN THE
FORECAST LATE...BUT POTENTIAL SEEMS LIMITED DURING THE OVERNIGHT
HOURS WITH THE SHORT PERIOD OF AT OR BELOW FREEZING TIME.
OTHERWISE...WILL ONLY MENTION A LOW CHANCE FOR SNOW OVER THE WEST
OVERNIGHT DUE TO LIMITED ICE CRYSTAL PRESENCE AND RAIN OVER THE
CENTRAL AND EAST. THINK THE BIGGEST HAZARD IS MORE LIKELY TO BE THE
WET ROADS ICING UP ON THURS...AS TEMPS FALL BELOW FREEZING THROUGH
THE DAY.
NRN STREAM UPPER TROUGH WILL SWEEP THROUGH THE CWA ON THURS. STILL
DIFFERENCES IN THE SPEED/INTENSITY IN THE MODELS WITH THIS
WAVE...BUT ALL HAVE THE GENERAL IDEA OF IT MOVING THROUGH THE UPPER
GREAT LKS ON THURS. THIS WAVE WILL DROP H850 TEMPS THROUGH THE DAY
TO -12C OVER THE W BY 00Z FRI. THESE COLDER TEMPS WILL STAY OVER THE
AREA THROUGH THE DAY FRI...ANOTHER WEAKER SHORTWAVE DROPS ACROSS THE
AREA. WITH TEMPS ALOFT PUTTING THE CLOUD LAYER BACK INTO THE ICE
CRYSTAL AREA ON THURS...EXPECT TO CHANCES FOR SNOW AS THE P-TYPE TO
BE ON THE INCREASE FROM WEST TO EAST. SHORTWAVE ENERGY WILL HELP
ENHANCE THE DEVELOPING LES THROUGH THE DAY. WILL CONTINUE TREND OF
HIGHER POPS OVER THE WEST IN THE MORNING WITH LES DEVELOPING AND
SHORTWAVE ARRIVING...THEN INCREASE LES POPS OVER THE E UNDER NW
WINDS IN THE AFTN INTO THURS NIGHT. IN ADDITION...WITH THE LOW
INTENSIFYING TO THE NE OF THE AREA...EXPECT A BREEZY DAY ON THURS
ACROSS THE AREA. THE HIGHEST WINDS SHOULD BE OVER THE E NEAR LK
SUPERIOR...WHERE WINDS COULD GUST TO 40-45MPH LATE IN THE AFTERNOON.
SFC RIDGE QUICKLY MOVES FROM W TO E OVER THE CWA ON THURS NIGHT INTO
FRI. MODELS SHOWING VERY PRONOUNCED H925-700 DRYING WITH THE ARRIVAL
OF THE RIDGE...SO HAVE TRENDED BACK LES POPS...ESPECIALLY OVER THE
WEST WHERE BUFKIT SOUNDINGS SHOWING INVERSION HEIGHTS FALLING
TOWARDS 3KFT. DID KEEP LIKELY/S OVER THE NW WIND FAVORED E LOCATIONS
THURS NIGHT INTO FRI MORNING...BUT DROPPED TO CHANCES IN THE AFTN AS
THE DRY AIR LIMITS POTENTIAL.
DAYS 4 THROUGH 7 /FRI NIGHT THROUGH NEXT TUESDAY/...
WEAK SHORTWAVE MOVING ACROSS THE AREA FRI NIGHT WILL BRING A LITTLE
MORE MOISTURE TO THE AREA AND KEEP COLDER AIR IN PLACE. EXPECT
ONGOING LES TO CONTINUE OVER THE E...WITH WINDS GRADUALLY SHIFTING
MORE WRLY. LES MAY TRY TO REDEVELOP OVER THE W WITH THE ARRIVAL OF
THE SHORTWAVE AND ADDITIONAL LLVL MOISTURE. WILL GO WITH LOW CHANCES
OVER THE KEWEENAW WITH THE MORE WRLY WINDS AND THEN LOW END LIKELY/S
OVER THE EAST.
UPPER TROUGH SHIFTS E ON SAT AND DRAGS A SFC TROUGH OVER NRN LK
SUPERIOR AND SRN ONTARIO THROUGH THE DAY AND INTO SAT NIGHT. THERE
HAS BEEN A STRONGER TREND WITH THE SFC FEATURES AND UPPER FORCING
OVER THE LAST DAY FOR THE SAT AND SAT NIGHT PERIOD...SO HAVE BUMPED
POPS UP TO SLIGHTS OVER THE NRN U.P. AND CHANCES OVER THE LAKE.
SOME DIFFERENCES APPEAR IN THE EXTENDED MODELS ON SUN INTO MON WITH
THE HANDLING OF A POTENTIAL RIDGE IN THE NRN STREAM AND A CLOSED LOW
OVER THE SW CONUS. LATEST 12Z RUN OF THE GFS HAS TRENDED SLOWER WITH
THE EXIT OF THE UPPER LOW OVER THE SW CONUS SUN INTO MON...AND MORE
IN LINE WITH THE 00Z ECMWF...SO HAVE FOLLOWED THAT FOR THE REST OF
THE EXTENDED. SFC RIDGE WILL MOVE ACROSS THE CWA ON SUN INTO SUN
NIGHT. NRN STREAM SHORTWAVE WILL APPROACH THE AREA MON INTO
TUES...BRINGING ANOTHER LOW CHANCE OF PCPN. HAS BEEN A GOOD AMOUNT
OF FLUCTUATION IN H850 TEMPS AFTER SUN...SO HAVE LIMITED CONFIDENCE
IN VALUES...BUT APPEARS THAT TEMPS WILL SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
LOW-LEVELS SHOULD REMAIN MOIST THROUGH THE TAF PERIOD WITH LIMITED
MIXING AS A WEAK TROUGH OF LOW PRESSURE REMAINS OVER UPPER MICHIGAN.
ALL TAF SITES WILL EXPERIENCE LOWER IFR CONDITIONS WITH CONDITIONS
POSSIBLY FALLING TO AROUND AIRPORT MINIMUMS WHEN WINDS PROVIDE
ADDITIONAL UPSLOPE LIFT. SOME DRYING MAY WORK INTO THE AREA TONIGHT
AS WINDS BECOME MORE SOUTHERLY. BEST CHANCE OF IMPROVEMENT WILL BE AT
KIWD WITH DOWNSLOPE WINDS...WHILE KSAW WILL REMAIN IFR AS SRLY WINDS
ADD ADDITIONAL MOISTURE OFF OF LK MICHIGAN AND ALSO PROVIDE SOME
UPSLOPE. CONFIDENCE IN DETAILS THROUGH ENTIRE TAF PERIOD IS ON THE
LOW SIDE. IN GENERAL...SIGNIFICANT IMPROVEMENT IS NOT ANTICIPATED
THROUGH WEDNESDAY MORNING.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LIGHT SOUTHERLY WINDS WILL INCREASE INTO THE 15 TO 25 KT RANGE OVER
THE CENTRAL AND EAST PORTIONS OF THE LAKE WED AHEAD OF LOW PRESSURE
DEVELOPING IN THE PLAINS. THE LOW IS FCST TO DEEPEN AS IT LIFTS
ACROSS THE UPPER LAKES BY THURSDAY MORNING. STRONGEST WINDS THIS
WEEK WILL OCCUR JUST IN THE WAKE OF THE LOW THURSDAY MORNING THROUGH
MIDNIGHT THURSDAY NIGHT. CONFIDENCE THAT 35-40 KT GALES WILL OCCUR
IS HIGH SO THE WATCH CONTINUES FOR MUCH OF LK SUPERIOR. STRONG WINDS
WILL DIMINISH ON FRI WITH THE SLOW APPROACH OF A HIGH PRESSURE
RIDGE. A STRONGER SW FLOW WILL REDEVELOP ON SAT AFTER THIS HIGH
SHIFTS TO THE SE WITH WINDS TO AROUND 30 KT OVER WEST AND CENTRAL
PORTIONS OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
LSZ264>267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 AM EST TUE DEC 13 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.UPDATE...
ISSUED A FREEZING RAIN ADVISORY THROUGH TUE MORNING...SINCE DRIZZLE
WAS FALLING OVER MUCH OF CENTRAL AND WRN UPPER MI WITH TEMPS ALREADY
AT FREEZING INLAND. HARD TO TELL WHEN DRIZZLE WILL STOP...BUT SHOULD
CONTINUE INTO TUE MORNING AS LOW LEVEL MOISTURE HANGS OVER THE
AREA...THE DGZ REMAINS DRY...AND TEMPS SLOWLY FALL TONIGHT.
&&
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA WITH SRN BRANCH SW FLOW ALF OVER THE GRT LKS BTWN RDG OVER
THE ERN CONUS AND A WRN TROF. A SHRTWV EMBEDDED IN THIS SW FLOW IS
OVER MN AND CAUSING AN AREA OF -RA OVER WI INTO SE UPR MI...WHERE
DEEPER MSTR IS PRESENT. SOME SN IS MIXING IN WITH THIS PCPN IN THE
PRESENCE OF DYNAMIC COOLING ACCOMPANYING THE SHRTWV EVEN THOUGH SFC
TEMPS ARE ABV 32. ISSUED SPS THIS AFTN TO ACCOUNT FOR PERIODS OF
HEAVY SN/SLUSHY ACCUMS IN A SWATH OVER THE CNTRL WHERE DYNAMIC
COOLING RELATED TO AREA OF H85-7 FGEN IS MOST PRONOUNCED. OTRW...
TEMPS OVER THE ENTIRE CWA ARE WELL ABV NORMAL AND IN THE 30S.
ABUNDANT LLVL MSTR WITH DWPTS ALSO IN THE 30S IN LGT SW SFC FLOW HAS
CAUSED QUITE A BIT OF LO CLD/FOG OVER THE CWA...BUT A COLD FNT TO
THE N ASSOCIATED WITH A DISTURBANCE IN THE ARCTIC BRANCH OVER CAN IS
PRESSING SLOWLY SWD INTO LK SUP. THE COLD AIR BEHIND THIS FNT IS
QUITE SHALLOW PER THE 12Z INL RAOB...BUT SFC TEMPS AT NOON FALL
QUITE SHARPLY FM ARND 35 OVER THE KEWEENAW AND AHEAD OF THE FNT TO
19 AT THUNDER BAY ONTARIO.
&&
.SHORT TERM DISCUSSION /TNGT AND TUE/...
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN CHCS/PTYPE ASSOCIATED
WITH SHRTWV LIFTING INTO WI. FOCUS FOR LATER TNGT AND TUE SHIFTS TO
INFLUX OF COLDER/DRIER AIR FM THE N AND IMPACT ON THE WX.
TNGT...SHRTWV OVER WI AND ACCOMPANYING DYNAMICS/DEEPER MSTR ARE
PROGGED TO LIFT OUT AND EXIT THE ERN ZNS BY LATE EVNG...SO GOING
MORE WDSPRD MIXED PCPN OVER MAINLY THE SE HALF WL DIMINISH WITH MID
LVL SUBSIDENCE/DRYING OVERSPREADING THE FA. HOWEVER...INFLUX OF
SHALLOW COLD AIR FOLLOWING NW-SE PASSAGE OF SFC COLD FNT WL MAINTAIN
A SHARP LLVL INVRN AND PRESENT OVC ST/SC DECK. IN PLACES WITH
UPSLOPE WIND FLOW...OPTED TO MAINTAIN MENTION OF -DZ/-FZDZ WITH
SHALLOW MSTR WELL BLO THE DGZ AND UNDER SUBSIDENCE ALF. CONSIDERING
THE LLVL CHILL OBSVD UPSTREAM...TENDED TO GO TOWARD THE LO SIDE OF
GUIDANCE FOR TEMPS FOLLOWING THE COLD FROPA. EVEN SO...AIRMASS WL
NOT BE SUFFICIENTLY COLD TO SUPPORT LES WITH SHARP INVRN.
TUE...SHALLOW COLD WEDGE WL REMAIN IN PLACE WITH SLOWING VEERING
FLOW TO MORE ESE IN THE AFTN AS CENTER OF HI PRES IN ONTARIO DRIFTS
TO THE E. WITH COLD WEDGE GETTING A BIT MORE SHALLOW...SUSPECT
LINGERING -DZ/-FZDZ WL BE MORE TIED TO UPSLOPE FLOW OVER THE NCNTRL
WHERE THERE WL BE ADDITIONAL MOISTENING OFF LK SUP. EXPECT LTL
DIURNAL TEMP RISE WITH LINGERING LO CLD OVC.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
ACTIVE MID TERM PORTION OF THE FORECAST...WITH A LOW PRESSURE SYSTEM
MOVING THROUGH THE AREA AROUND MID WEEK AND PROVIDING A WINTRY MIX
OF PCPN.
TUES NIGHT...UPPER RIDGE AXIS WILL BE SHIFTING E OF THE CWA THROUGH
THE NIGHT. SHOULD KEEP MUCH OF THE AREA DRY...ALTHOUGH PERSISTANT
LOW CLOUDS WILL BE COVERING MUCH OF THE AREA. WITH INCREASING
ISENTROPIC ASCENT AROUND THE 280 SFC AND DRY AIR ABOVE
5KFT...WOULDN/T BE SURPRISED IF THE SWRN HALF OF THE CWA EXPERIENCES
SOME DZ/FZDZ...SO HAVE PUT THE MENTION IN FOR MUCH OF THE NIGHT.
TRANSITIONED TO A RA/SN MIX ALONG THE WI BORDER OVERNIGHT...AS THE
280-300K ISENTROPIC ASCENT BEGINS TO MOVE INTO THE AREA. WITH THE
MOISTURE EATING AWAY AT THE DRY AIR...EXPECT THE DZ/RA TO QUICKLY
TRANSITION TO MAINLY SNOW ALONG THE BORDER AS ICE BECOMES PRESENT
AND THERE IS A NEARLY ISOTHERMAL LAYER AT/BELOW 0C FROM THE SFC TO
6KFT.
WITH THE MAIN TROUGH STILL WELL TO THE SW IN THE FOUR CORNERS
REGION...WEAK SHORTWAVE ENERGY WILL BE EJECTING NE TOWARDS THE AREA
ON WED. THIS WILL PUSH A WEAK LOW PRESSURE TROUGH ACROSS THE CWA
THROUGH THE DAY. BEST CHANCES OF PCPN ARE S AND E...CLOSER TO THE
MAIN PUSH OF THE SHORTWAVE...ALONG WITH H850-700 WAA AND ISENTROPIC
ASCENT. THIS AREA OF PCPN SHOULD QUICKLY MOVE NE THROUGH THE CWA
DURING THE MORNING AND EARLY AFTN AND LEAD TO A SLIGHTLY DRIER
PERIOD OVER THE W IN THE LATE AFTN BEFORE THE NEXT WAVE AFFECTS THE
AREA. DIFFICULTY IN THE FCST COMES FROM PCPN TYPE...AS THERE COULD
BE A MIXED BAG WITH THE PASSAGE OF THE SYSTEM. SOUNDINGS CONTINUE TO
SHOW A NEARLY ISOTHERMAL 0C LAYER FROM SFC TO 7KFT FOR THE
CENTRAL/WRN PORTIONS OF THE AREA...WHICH WOULD SUPPORT SNOW IN THE
MORNING. THEN AS SRLY WINDS INCREASE THROUGH THE DAY...LLVL TEMPS
LOOK TO RISE AND LEAVE THE LOWEST 2-4KFT ABOVE FREEZING /TOWARDS
2-3C/. AT THAT SAME TIME...THE DEEP MOISTURE EXITS THE AREA AND
THERE WILL LIKELY BE LITTLE/NO ICE POTENTIAL IN THE CLOUDS...SO HAVE
WENT MAINLY RAIN...WITH JUST A MENTION OF SNOW OVER THE N. MAY END
UP BEING JUST A -RA/DZ SITUATION IN THE LATE AFTN BEFORE NEXT WAVE
ARRIVES.
MAIN SHORTWAVE FROM THE SW FLOW ARRIVES ON WED NIGHT OVER THE ERN
CWA...WHICH MODELS RESPOND TO BY INTENSIFYING THE LOW OVER THE UPPER
GREAT LAKES. AT THE SAME TIME...NRN STREAM SHORTWAVE BEGINS TO ENTER
THE NRN PLAINS AND PHASES WITH THE SRN STREAM. MODELS HAVE A
NOTORIOUSLY TOUGH TIME WITH THESE EVENTS AND IT APPEARS THAT IT
CONTINUES WITH THIS SITUATION. ISSUES APPEAR WITH THE
TIMING/STRENGTH OF THE NRN STREAM WAVE...WHICH AFFECTS
INTENSITY/TRACK OF LOW. TRENDS IN THE GFS/ECMWF OVER THE LAST DAY OR
TWO HAVE BEEN FOR A WEAKER LOW TO TRACK ACROSS THE FAR ERN CWA WITH
A WEAKER NRN STREAM WAVE. WILL FOLLOW THAT TREND FOR THE WED NIGHT
AND THURS FORECAST...WITH AN EMPHASIS ON THE HPC PREFERRED GFS.
THEREFORE...HAVE THE HIGHEST POPS /80 PLUS/ OVER THE ERN HALF OF THE
CWA WITH THE BEST FORCING/MOISTURE. EXPECT THIS TO BE MAINLY RAIN
OVER THE EAST HALF...BUT IF THE ECMWF ENDS UP BEING CORRECT THERE
COULD BE SOME MIXING LATE.
FCST IS A LITTLE MORE TRICKY OVER THE W...SINCE IT IS ON THE FRINGE
OF THE BEST DEEP MOISTURE AND FORCING. IF PCPN OCCURS...HAVE A
FEELING THAT POTENTIAL FOR ICE IN THE CLOUDS IS LIMITED. HAVE
TRENDED TOWARDS MORE OF A RA SITUATION UNTIL THE COLDER AIR ARRIVES
TOWARDS DAYBREAK THURSDAY. DEPENDING ON HOW QUICKLY TEMPS FALL
DURING THE NIGHT AND INTO THURS MORNING...COULD SEE A PERIOD OF FZDZ
BEFORE TURNING TO ALL SNOW DURING THE MORNING.
THE LOW SHOULD THEN INTENSIFY OVER QUEBEC ON THURS...AS THE
SHORTWAVES PHASE. WITH SFC HIGH OVER THE NRN PLAINS AND JUST E OF
THE CANADIAN ROCKIES...EXPECT NW WINDS AND H850 TEMPS NEAR -12C TO
LEAD TO AT LEAST SOME LES DEVELOPING. INVERSION HEIGHTS AROUND
6-8KFT GIVES A DECENT CLOUD DEPTH...BUT WITH BEST FORCING BELOW THE
DGZ WILL LIMIT SNOW GROWTH. OPTED TO BUMP POPS UP HEADING INTO THE
AFTN...AS MORE FAVORABLE CONDITIONS FOR LES ARRIVE...ESPECIALLY
SINCE THE NRN CWA SHOULD BE SEEING WRAP AROUND MID-LVL MOISTURE FROM
THE LOW. FINALLY...SHOULD BE A BREEZY DAY ON THURS...WITH GUSTS
ALONG THE ERN LK SUPERIOR SHORELINE APPROACHING 40MPH.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
OVERALL...GOOD AGREEMENT IN THE EXTENDED MODELS ON THE OVERALL
PATTERN FOR THE EXTENDED PERIOD. ON THURS NIGHT...UPPER TROUGH WILL
BE PUSHING THROUGH THE AREA AND DROPPING H850 TEMPS TOWARDS -14C.
SHOULD STILL BE SOME MID-LVL MOISTURE OVER THE E BEFORE THE MOISTURE
EXITS THE AREA ON FRI AS THE INVERSION HEIGHTS FALL TOWARDS 5KFT
WITH HIGH PRESSURE RIDGE MOVING OVER THE WRN CWA. THUS...LES
INTENSITY SHOULD HIT IT/S PEAK THURS NIGHT...AS SHOWN IN LES
PARAMETER...BEFORE DIMINISHING IN INTENSITY THROUGH FRI. ONLY MADE
MINOR TWEAKS UP TO THE POPS OVER THE EAST AND THEN BUMPED UP TO HIGH
END CHANCE AND LOW LIKELY/S OVER THE NW WIND SNOW BELTS OVER THE
WEST FOR THURS NIGHT INTO FRI...ALTHOUGH THE CHANCES WILL DIMINISH
OVER THE W IN THE AFTN. IN ADDITION...WEAK SHORTWAVE ON FRI COULD
BRING SOME MID CLOUDS.
SFC HIGH PRESSURE RIDGE WILL QUICKLY MOVE EAST OF THE AREA ON FRI
NIGHT...WITH MODELS CONSISTENT ON A SHORTWAVE MOVING THROUGH THE
UPPER MISS VALLEY ON SAT. THIS WAVE WILL LIKELY DIVE S OF THE
CWA...AND CARRY THE BEST MOISTURE AND H850-500 Q-VECTOR CONV WITH
IT. OTHER THAN LINGERING LES OVER THE NW FAVORED LOCATIONS OVER THE
E IN THE MORNING BEFORE WIND SHIFT TO THE SW...WILL KEEP THE REST OF
THE CWA DRY.
UPPER RIDGE MOVING THROUGH SUNDAY...WITH H850 TEMPS RISING TOWARDS
1-4C. SHOULD LEAD TO ANOTHER WARM SUNDAY ACROSS THE AREA...BUT MAY
NOT BE QUITE AS WARM AS YESTERDAY/S HIGHS. DID BUMP UP TEMPS FROM
THE CONSENSUS OVER THE DOWNSLOPE AREAS NEAR LK SUPERIOR INTO THE
UPPER 30S. NEXT TROUGH WILL AFFECT THE AREA SUN NIGHT INTO
MON...BRINGING ANOTHER CHANCE OF PCPN TO THE AREA. DIFFERENCES IN
HOW AMPLIFIED THE TROUGH IS...ALONG WITH MOISTURE RETURN FROM THE
GULF...SO WILL LEAVE POPS AT SLIGHT/CHANCES.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT SLOWLY IMPROVING CONDITIONS THROUGH THE TAF PERIOD.
PREDOMINANT CONDITIONS THROUGH AT LEAST THE MORNING HOURS WILL BE
IFR AS LOW LEVELS ARE VERY MOIST. DRIZZLE/FREEZING DRIZZLE WILL BE
POSSIBLE AT ALL TAF SITES DURING THE PERIOD. THERE IS ABOVE NORMAL
UNCERTAINTY IN HOW LONG LOW VIS AND CIGS WILL STICK AROUND. THE BEST
CHANCE FOR IMPROVEMENTS WILL BE AT IWD LATE IN THE TAF PERIOD AS FLOW
BECOMES LESS FAVORABLE FOR POOR CONDITIONS. &&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO EARLY WED AS A
LOW PRESSURE TROUGH SLOWLY SLIDES ACROSS LK SUPERIOR. WINDS BECOME
MORE SOUTHERLY AS ANOTHER LO PRES SYSTEM DEVELOPING IN THE PLAINS
BEGINS TO LIFT TOWARD THE UPPER GREAT LAKES. SE WINDS AHEAD OF THIS
LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF ON WED. THE
MAIN HAZARD WILL BE AFTER THE LOW MOVES TOWARD QUEBEC ON THU...WHEN
NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING
WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE
SLOW APPROACH OF HI PRES. A STRONGER WSW FLOW WILL REDEVELOP ON SAT
AFTER THIS HI SHIFTS TO THE SE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ002-004>006-009>013-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TITUS
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...SRF
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
410 PM CST TUE DEC 13 2011
.DISCUSSION...
MAIN EMPHASIS THIS FORECAST WAS SPENT ON SYSTEM THAT WILL IMPACT
THE AREA TONIGHT THROUGH WEDNESDAY...WITH BASICALLY AN ALL RAIN
SCENARIO EXPECTED. AFTER THAT...LOOKS MAINLY DRY...WITH THE
PROSPECTS OF A BROWN CHRISTMAS FOR MOST OF THE NRN PLAINS/UPPER MS
VALLEY LOOKING LIKE A DISTINCT POSSIBILITY. THIS WOULD BE THE
FIRST SNOW FREE CHRISTMAS IN THE TWIN CITIES /AND MOST OF THE REST
OF THE AREA FOR THAT MATTER/ SINCE 2006.
THIS AFTERNOON...DEEP UPPER LOW OVER THE DESERT SW...WHICH BROUGHT
SOME DECENT RAINS/SNOWS TO AZ BEGINNING TO LIFT ENE. MOISTURE
PLUME ON WATER VAPOR HAS BEEN SPREADING NE...WITH SCT RADAR RETURNS
WORKING NORTH ACROSS NEB/IA. 12Z MODELS ARE FAIRLY CONSISTENT
WITH A SCENARIO FOR THIS SYSTEM SETTING UP WHERE WE GET A WAA WING
OF PRECIP TONIGHT /WHAT IS NOW GATHERING STEAM DOWN BY
OMAHA/...FOLLOWED BY A BIT OF A LULL IN PRECIP WED MORNING BETWEEN
THE WAA PRECIP TONIGHT...AND WHAT LOOKS TO BE A BAND OF
DEFORMATION PRECIP THAT SETS UP WED AFTERNOON. SOME DISAGREEMENT
ON WHERE THIS SECOND BAND OF PRECIP SETS UP...BUT THE
GEM/GFS/ECMWF ALL SHOW A SW-NE ORIENTED BAND OF RAIN SETTING UP
SOMEWHERE BETWEEN THE TWIN CITIES AND ROCHESTER DURING THE
AFTERNOON. ONE BIG WORRY I HAVE FOR THIS SYSTEM IS THE FACT THAT
LOW LEVEL MOISTURE TRANSPORT IS PEGGED TO RIDE UP INTO SE IA AND
SE WI...REMAINING WELL SE OF HERE. IN ADDITION...STILL INDICATIONS
FROM THE BEST LI`S OFF THE NAM/GFS THAT THIS REGION OF MOISTURE
TRANSPORT COULD ALSO SEE THUNDER ON WEDNESDAY...THIS COULD CONSUME
A LOT OF THE MOISTURE THAT WOULD OTHERWISE COME UP HERE...WITH THE
RELATIVELY DRY 12Z NAM SCENARIO FOR THE MPX CWA NOT OUT OF THE
QUESTION. AS FOR THAT AFTERNOON DEFORMATION BAND...FGEN WITHIN IT
LOOKS TO BE FAIRLY STRONG...AND IF IT DOES SETUP...LIKE THE IDEA
THE GFS GIVES OF A BAND OF A HALF INCH OR MORE OF RAIN SETTING UP
WITH IT. UNDER NORMAL DECEMBER CIRCUMSTANCES...THIS WOULD RESULT
IN A HEALTHY BAND OF INTENSE SNOWFALL...BUT ALL INDICATIONS SHOW
THIS BEING A VERY WARM SCENARIO...WITH ANY WINTRY PRECIP NOW
BEGINNING TO LOOK UNLIKELY...AS PRECIP LOOKS TO MOVE EAST OF THE
AREA BEFORE THICKNESSES BEGIN TO CRASH.
AS FOR THE POSSIBILITY OF WINTER WEATHER STATEMENTS
TONIGHT FOR WRN MN...DECIDED AGAINST DOING SO FOR TWO REASONS.
FIRST...THERE ARE NO SITES LEFT IN THE MPX CWA WITH TEMPERATURES
AT OR BELOW 32F. WITH SE FLOW EXPECTED TO REMAIN IN PLACE ALL
NIGHT...IT IS HIGHLY QUESTIONABLE IF ANYONE WILL FALL BELOW
FREEZING TONIGHT...KEEPING ALL PRECIP IN THE FORM OF LIQUID RAIN
TONIGHT. SECOND...WITH THE 12Z MODEL RUNS...IT IS QUESTIONABLE IF
AREAS NW OF A RWF TO MILLE LACS LAKE LINE WILL SEE MUCH IN THE WAY
OF PRECIP OUT OF THIS EVENT...FURTHER DECREASING THE CONFIDENCE IN
THE NEED FOR ANY WINTER STATEMENTS TONIGHT.
THIS SYSTEM WILL PULL OUT OF THE AREA THURSDAY NIGHT...WITH
THURSDAY BEING CHARACTERIZED BY STRONG CAA MOST OF THE DAY...WITH
A COUPLE OF BELOW TO NEAR NORMAL TEMPERATURE DAYS TO END THE WEEK.
FOR WEDNESDAY NIGHT...WARMED THE LOWS SEVERAL DEGREES ACROSS ERN
MN AND WRN WI...AS MODELS SHOW STRONG CAA WAITING UNTIL THE DAY ON
THURSDAY TO MOVE THROUGH...WITH CLOUDS HANGING AROUND MOST OF THE
NIGHT. GIVEN THE STRONG CAA ON THURSDAY...LOOKS TO BE YET ANOTHER
DAY WHERE TEMPERATURES GO SIDEWAYS OR SLOWLY FALL DURING THE DAY.
USED A NON-DIURNAL TREND IN TEMPERATURES WEDNESDAY NIGHT AND
THURSDAY BASED OFF THE REGIONAL GEM.
GOING INTO THE WEEKEND...WRLY FLOW WILL QUICKLY SET IN...WITH
HIGHS BACK INTO THE 30S ALREADY RETURNING FOR SATURDAY. SUNDAY
LOOKS TO WARM EVEN FURTHER AS SRLY FLOW SETS UP OUT AHEAD OF THE
NEXT FRONTAL BOUNDARY...WHICH THE ECMWF CONTINUES TO SHOW MOVING
IN ON MONDAY. DEPENDING ON HOW MUCH SUN THERE THERE IS...SUNDAY
COULD BE YET ANOTHER CANDIDATE THIS MONTH FOR HIGHS IN THE 40S.
FOR THE MONDAY SYSTEM...THE GFS/ECMWF SHOWING A SPLIT FLOW SCENARIO
SETTING UP...WHERE ONCE AGAIN THE MPX AREA ENDS UP BETWEEN WEATHER
SYSTEMS AND DRY. FOR THIS SYSTEM...MODELS SHOW ANOTHER UPPER LOW
CLOSING OFF OVER THE DESERT SW OVER THE WEEKEND...WITH NRN STREAM
ENERGY MOVING ACROSS THE NRN PORTIONS OF THE SRN CANADIAN
PROVINCES. THIS NRN WAVE LOOKS TO BE TOO FAR NORTH TO IMPART MUCH
INFLUENCE ON THE SW LOW. AS A RESULT...THE GFS/ECMWF TAKE THIS LOW
WELL SOUTH OF THE AREA...KEEPING THE MPX AREA HIGH AND DRY. AS THE
SAYING GOES...WHEN IN DROUGHT LEAVE IT OUT.
&&
.AVIATION... /18Z TAF ISSUANCE/
VFR CEILINGS CONTINUE TO WORK SLOWLY NORTHWEST ACROSS THE TWIN
CITIES. IMPROVEMENT SHOULD WORK INTO KRNH BY 21Z. ONE CONCERN IS
THE NEGATIVE CU RULE WHICH WOULD SUGGEST THAT A BKN LAYER IN THE
015-020 RANGE COULD REDEVELOP THIS AFTERNOON. RUC PROFILE DATA
SHOWS THIS IMPROVING SITUATION NICELY AND ACTUALLY HAS 040
CEILINGS PREVAILING TO NEAR 08Z. THERE IS SOME CONCERN THAT THIS
LOW LEVEL DRYING MAY MAKE IT INTO KSTC THIS EVENING. THE OTHER
PROBLEM IS VISIBILITIES. IMPROVEMENT WILL OCCUR AT KAXN AND KSTC
AS THE SE LOW LEVEL FLOW INCREASES. THESE TWO SITES SHOULD SEE
3SM IN THE 21Z-22Z TIME FRAME. RAIN WILL SPREAD ACROSS THE CWA
TONIGHT AS A WAVE OF LOW PRESSURE APPROACHES FROM THE SW. THE
TIMING ON THE RAIN REMAINS SIMILAR TO THE PREVIOUS TAF PACKAGE.
THERE IS STILL SOME POTENTIAL FOR -FZRA AT KAXN AT THE BEGINNING
OF THE PRECIPITATION WITH RAIN ELSEWHERE. THE PRECIPITATION COMES
IN TWO PHASES WITH KAXN...KSTC AND KRWF DRYING OUT WEDNESDAY
MORNING WHILE ANOTHER ROUND OF RAIN SPREADS NORTHEAST ACROSS
KMSP...KRNH AND KEAU.
KMSP...CEILINGS AROUND 040 EXPECTED THIS AFTERNOON WITH TEMPORARY
BKN015. WENT PREDOMINANT BKN-OVC015 AT 23Z BUT THIS MAY BE TOO
EARLY BASED ON THE RAPID UPDATE CYCLE AND PERHAPS VFR CEILINGS
LAST THROUGH THE EVENING. RAIN EXPECTED INTO THE AIRFIELD AFTER
06Z AND LASTING TO NEAR DAYBREAK. A BREAK IN THE RAIN WEDNESDAY
MORNING WITH MORE LIGHT RAIN OCCURRING WEDNESDAY AFTERNOON AS LOW
PRESSURE ACROSS NORTHERN IA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/RAH
AREA FORECAST DISCUSSION
NWS DULUTH MN
207 PM CST TUE DEC 13 2011
.UPDATE...
EXPIRED THE WIS COUNTIES FROM THE FZRA ADVISORY AS TEMPS HAVE
WARMED ENOUGH TO MELT THE ICE COVERED ROADS FROM THIS MORNING. THE
WIS DEPT OF TRANSPORTATION REPORTS ROAD CONDITIONS HAVE IMPROVED
TO GOOD WINTER DRIVING ACROSS NRN WIS. ALTHOUGH A FEW LOCATIONS
IN THE HIGHER TERRAIN MAY FALL AROUND FREEZING
OVERNIGHT...EXPECTING THE SOUTH WINDS TO KEEP MAJORITY OF THE AREA
WARM ENOUGH TO PREVENT ICE ACCUMULATIONS WITH LINGERING DRIZZLE OR
FOG.
&&
.PREV DISCUSSION... /ISSUED 557 AM CST TUE DEC 13 2011/
AVIATION...12Z TAF ISSUANCE...
LIFR/IFR CIGS AND VSBYS ACROSS THE REGION THIS MORNING WILL
IMPROVE SLIGHTLY BY THE LATE MORNING...WITH -FZDZ AROUND DLH AND
HIB TERMINALS. CIGS COULD POSSIBLY LIFT TO LOW-END MVFR...BUT WILL
LOWER AGAIN BY 00Z TO IFR AND POSSIBLY LIFR LATER IN THE EVENING
AND THROUGH THE OVERNIGHT. WILL SEE A CHANCE OF -FZDZ AGAIN THIS
EVENING AS COLD AIR REMAINS IN PLACE BUT A SURGE OF LOW LEVEL
MOISTURE GETS PUMPED INTO THE REGION FROM THE SOUTH. ENOUGH WARM
AIR AROUND BRD WILL KEEP PRECIP RAIN AND/OR SNOW. PATCHY IFR FOG
WILL ALSO RETURN AGAIN TONIGHT.
PREV DISCUSSION... /ISSUED 403 AM CST TUE DEC 13 2011/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 35 27 27 / 30 70 60 20
INL 26 34 19 20 / 20 40 40 20
BRD 31 35 22 26 / 50 60 40 10
HYR 33 36 30 30 / 30 80 80 20
ASX 32 37 30 31 / 30 80 80 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GRANING
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1159 AM CST TUE DEC 13 2011
.AVIATION... /18Z TAF ISSUANCE/
VFR CEILINGS CONTINUE TO WORK SLOWLY NORTHWEST ACROSS THE TWIN
CITIES. IMPROVEMENT SHOULD WORK INTO KRNH BY 21Z. ONE CONCERN IS
THE NEGATIVE CU RULE WHICH WOULD SUGGEST THAT A BKN LAYER IN THE
015-020 RANGE COULD REDEVELOP THIS AFTERNOON. RUC PROFILE DATA
SHOWS THIS IMPROVING SITUATION NICELY AND ACTUALLY HAS 040
CEILINGS PREVAILING TO NEAR 08Z. THERE IS SOME CONCERN THAT THIS
LOW LEVEL DRYING MAY MAKE IT INTO KSTC THIS EVENING. THE OTHER
PROBLEM IS VISIBILITIES. IMPROVEMENT WILL OCCUR AT KAXN AND KSTC
AS THE SE LOW LEVEL FLOW INCREASES. THESE TWO SITES SHOULD SEE
3SM IN THE 21Z-22Z TIME FRAME. RAIN WILL SPREAD ACROSS THE CWA
TONIGHT AS A WAVE OF LOW PRESSURE APPROACHES FROM THE SW. THE
TIMING ON THE RAIN REMAINS SIMILAR TO THE PREVIOUS TAF PACKAGE.
THERE IS STILL SOME POTENTIAL FOR -FZRA AT KAXN AT THE BEGINNING
OF THE PRECIPITATION WITH RAIN ELSEWHERE. THE PRECIPITATION COMES
IN TWO PHASES WITH KAXN...KSTC AND KRWF DRYING OUT WEDNESDAY
MORNING WHILE ANOTHER ROUND OF RAIN SPREADS NORTHEAST ACROSS
KMSP...KRNH AND KEAU.
KMSP...CEILINGS AROUND 040 EXPECTED THIS AFTERNOON WITH TEMPORARY
BKN015. WENT PREDOMINANT BKN-OVC015 AT 23Z BUT THIS MAY BE TOO
EARLY BASED ON THE RAPID UPDATE CYCLE AND PERHAPS VFR CEILINGS
LAST THROUGH THE EVENING. RAIN EXPECTED INTO THE AIRFIELD AFTER
06Z AND LASTING TO NEAR DAYBREAK. A BREAK IN THE RAIN WEDNESDAY
MORNING WITH MORE LIGHT RAIN OCCURRING WEDNESDAY AFTERNOON AS LOW
PRESSURE ACROSS NORTHERN IA.
&&
.DISCUSSION... /ISSUED 433 AM CST TUE DEC 13 2011/
SUMMARY...PRECIP STILL ON PACE TO MOVE IN TONIGHT AND LINGER INTO
EARLY THURSDAY MORNING. HAVE INCLUDED 90-100% POPS IN THE FORECAST
FOR WESTERN WI...EASTERN/SOUTHERN MN WEDNESDAY AFTERNOON WHICH IS
PROBABLY OUR BEST WINDOW FOR RAIN IN THESE AREAS. STILL
PREDOMINATELY A LIQUID PRECIP SCENARIO OUTSIDE OF WEST CENTRAL MN
WHERE MORE OF A MIX CAN BE EXPECTED.
WITH A STATIONARY BOUNDARY STRETCHED OUT ACROSS THE
AREA TODAY...WIDESPREAD LIGHT FOG WITH AREAS OF DENSE FOG CAN BE
EXPECTED THIS MORNING. THE DENSE FOG ADVISORY ENDS AT 15Z AND
THIS STILL SEEMS REASONABLE GIVEN THE WIND INCREASES SLIGHTLY OUT
OF THE SOUTHEAST LATE THIS MORNING. ALSO...SOMETIMES THE ADVECTION
OF HIGH CLOUDS OVER THE FOG AND STRATUS CAN HELP TO BREAK UP
THICKER FOG AND WE`LL ALSO HAVE THAT AS WELL THIS MORNING.
OTHERWISE...THERE ARE STRATUS CLOUDS AS FAR AS THE EYE CAN SEE WITH
VERY FEW BREAKS SHOWING UP ON MY ENTIRE REGIONAL SATELLITE LOOP
THIS MORNING. THIS MEANS TEMPERATURES WILL NOT DRIFT MUCH FROM
WHERE THEY ARE NOW. THE DIFFERENCE BETWEEN THE HIGH AND LOW AT THE
MINNEAPOLIS AIRPORT YESTERDAY WAS 4 DEGREES AND THERE HAS BEEN
ABOUT 15-20 HOUR PERIOD WHERE MANY SITES ACROSS THE AREA HAVE ONLY
CHANGED A DEGREE OR TWO. SAME STORY TONIGHT...WHICH IS GOOD NEWS
FOR MANY LOCATIONS...BECAUSE MOST LOCATIONS WILL BE ABOVE FREEZING
WHEN THE RAIN BEGINS.
PER THE PAST COUPLE SREF SOLUTIONS...BEST CHANCE FOR A
SNOW/FREEZING RAIN MIXTURE LOOKS TO BE FROM NORTH CENTRAL NEBRASKA
INTO WEST CENTRAL MINNESOTA. LOCATIONS IN WEST CENTRAL MN HAVE
DEWPOINTS IN THE MID 20S AND TEMPS IN THE UPPER 20S TO LOWER 30S
THIS MORNING. ALTHOUGH AS SOUTHEASTERLY FLOW INCREASE WE WILL SEE
WEAK WARM AIR ADVECTION...SOME OF THESE SITES WILL IMPROVE BY A
FEW DEGREES TODAY. HOWEVER...AREAS ALONG OR NORTHWEST OF A LINE
FROM MONTEVIDEO...TO SAUK CENTRE...TO LITTLE FALLS HAVE THE
POTENTIAL TO SEE SMALL ICE/SNOW ACCUMULATIONS LATE TONIGHT OR
EARLY WEDNESDAY MORNING. BESIDES THE NAM...WHICH IS STRONGER AND
FASTER WITH THIS SYSTEM...THERE IS FAIRLY DECENT AGREEMENT AMONGST
THE UKMET/GFS/ECMWF WITH THE 42-54HR FORECAST. THE 13.00Z NAM HAD
A VERY IMPRESSIVE STRIPE OF SNOW ACROSS WEST CENTRAL MN...WITH A
RUN TOTAL SNOW ACCUM OF 10-16" IN LOCATIONS NEAR ALEXANDRIA. THE
13.06 RUN HAS BACKED OFF ON TOTALS...BUT STILL HAS A HEALTHY 2-5"
SNOWBAND. THE NAM SEEMS TO HOT WITH ITS INITIALIZATION WITH 500MB
HEIGHTS ROUGHLY 60M TOO LOW RIGHT OUT OF THE GATE. THERE IS
LIGHTNING ALONG THE WEST COAST...SO IT`S CERTAINLY A DYNAMIC
SYSTEM...JUST THINK THE NAM IS TOO AGGRESSIVE. MUCH LESS SNOW IS
FORECAST IN THE OTHER GUIDANCE. I GUESS I`M NOT TOO CONCERNED
ABOUT THE FREEZING RAIN GETTING OUT OF HAND GIVEN THAT TEMPS WILL
BE NEAR FREEZING AND THE BULK OF THE PRECIP SHOULD FALL IN
SOUTHEAST MN AND WESTERN WI. IT WILL STILL HAVE TO BE MONITORED
FOR A FREEZING RAIN ADVISORY.
THE ONLY OTHER CONCERN IN THE EXPECTED RAIN AREAS OF SOUTHERN MN
AND WESTERN WI IS DUE TO THE PRESENCE OF WEAK STABILITY AND EVEN
THE HINT OF ELEVATED INSTABILITY. BEST LI OF NEAR ZERO COMES
RIGHT UP TO THE MN/IA WEDNESDAY AFTERNOON. DES MOINES OFFICE HAS
ISOLATED THUNDER IN THE FORECAST. ALTHOUGH THE FORECAST SOUNDINGS
SHOW A PRETTY DEEP WARM LAYER AND SURFACE TEMPS THAT WILL AT LEAST
BE IN THE MID 30S...IT SEEMS HARD TO GET CONVECTIVE SHOWERS IN MID
DECEMBER WITHOUT SOME CHANGE OVER TO ICE PELLETS. LEFT ALL RAIN IN
THE GRIDS FOR NOW...BUT IT`S SOMETHING TO WATCH.
IN THE EXTENDED...SPLIT FLOW PATTERN SUGGESTS THE MERCURY WONT BE
KEPT DOWN TOO LONG AFTER A SHOT OF COOLER AIR ON THURSDAY AND
FRIDAY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/CLF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
557 AM CST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE...
LIFR/IFR CIGS AND VSBYS ACROSS THE REGION THIS MORNING WILL
IMPROVE SLIGHTLY BY THE LATE MORNING...WITH -FZDZ AROUND DLH AND
HIB TERMINALS. CIGS COULD POSSIBLY LIFT TO LOW-END MVFR...BUT WILL
LOWER AGAIN BY 00Z TO IFR AND POSSIBLY LIFR LATER IN THE EVENING
AND THROUGH THE OVERNIGHT. WILL SEE A CHANCE OF -FZDZ AGAIN THIS
EVENING AS COLD AIR REMAINS IN PLACE BUT A SURGE OF LOW LEVEL
MOISTURE GETS PUMPED INTO THE REGION FROM THE SOUTH. ENOUGH WARM
AIR AROUND BRD WILL KEEP PRECIP RAIN AND/OR SNOW. PATCHY IFR FOG
WILL ALSO RETURN AGAIN TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 403 AM CST TUE DEC 13 2011/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 31 35 23 / 20 40 60 40
INL 29 24 33 16 / 10 20 40 40
BRD 33 31 34 22 / 10 50 50 30
HYR 36 32 36 28 / 10 40 70 60
ASX 36 32 37 28 / 20 30 60 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ038.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ006>009.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ001>004.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....TENTINGER
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
403 AM CST TUE DEC 13 2011
.SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
&&
.AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 31 35 23 / 20 40 60 40
INL 29 24 33 16 / 10 20 40 40
BRD 33 31 34 22 / 10 50 50 30
HYR 36 32 36 28 / 10 40 70 60
ASX 36 32 37 28 / 20 30 60 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ038.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ006>009.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ001>004.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....TENTINGER
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
310 PM MST TUE DEC 13 2011
.SHORT TERM...VALID FOR WED AND THU...
AREA OF STRATUS IN OUR EAST SLOW TO ERODE...AND AS OF 22Z LINGERS
FROM FORSYTH TO MILES CITY AND BAKER DOWN TO ALZADA...AND UP THE
TONGUE RIVER VALLEY AS WELL BUT SHERIDAN HAS BEGUN TO CLEAR OUT
OVER THE LAST HOUR. LOW LEVEL MOISTURE ACROSS OUR EAST WILL
GRADUALLY SCOUR OUT TONIGHT AS LATEST RUC ANALYSIS ALREADY SHOWS
INCREASED WESTERLY 850MB FLOW. THAT BEING SAID...SFC TROF ITSELF
REMAINS AT BIT EAST OF BILLINGS AND WE COULD SEE STRATUS LINGER
AND/OR SEE A LITTLE FOG DEVELOP EAST OF THIS TROF TONIGHT...
ESPECIALLY AS DEWPTS REMAIN IN THE UPPER TEENS AND LOWER 20S. HAVE
ADDED PATCHY FOG TO OUR EAST BUT WOULD EXPECT IT TO HAVE ERODED
COMPLETELY BY AROUND 12Z PER COLD FROPA AND ASSOCIATED WIND SHIFT
TO WESTERLY OVER TIME.
WEAK UPPER TROF REMAINS OVER EASTERN MONTANA...BUT UPSTREAM
SHORTWAVE IN SOUTHERN BRITISH COLUMBIA WILL BE A MINOR PLAYER AS
IT CLIPS THE AREA TOMORROW. SHOULD SEE SCATTERED SNOW SHOWERS OVER
THE MOUNTAINS BUT WILL KEEP POPS AT SLIGHT CHANCE FOR THE PLAINS
AS FORCING IS QUITE WEAK WITH DRY LOW LEVELS. OTHERWISE WILL SEE A
MODEST INCREASE IN SW-W THEN NW WINDS LATE TONIGHT AND TOMORROW
WITH THE FRONTAL PASSAGE.
AFTER A BRIEF BREAK IN THE WEATHER WEDNESDAY NIGHT...NEXT PACIFIC
WAVE WILL BEGIN TO IMPACT US THURSDAY. THIS WAVE WILL BE MORE
DYNAMIC BUT BRUNT OF ENERGY WILL DRIVE THROUGH THE GREAT BASIN
TOWARD THE FOUR CORNERS REGION...LEAVING WEAKER NORTHERN BRANCH
FORCING FOR US. THIS FORCING WILL BE COMPOSED OF SOME MID LEVEL
FRONTOGENESIS WHICH SHOULD FAVOR OUR NORTH TO NORTHEAST PARTS
INITIALLY ON THURSDAY...THEN UPPER TROF PASSAGE AND INSTABILITY
LATE THURSDAY AND THURSDAY NIGHT...DURING WHICH MODELS SHOW FAIR
Q-VECTOR CONVERGENCE. SHOULD AT LEAST SEE A QUICK COUPLE INCHES OF
SNOW FOR THE MOUNTAINS. POTENTIAL EXISTS FOR A LITTLE ACCUMULATION
FOR THE LOWER ELEVATIONS AS WELL...MAINLY IN OUR EAST AND NW FLOW
UPSLOPE AREAS...BUT DO NOT ANTICIPATE HIGHLIGHT CRITERIA ANYWHERE
AT THIS TIME. AGAIN THIS IS DUE TO SPLITTING NATURE OF THIS
PACIFIC ENERGY.
NO EXTREME TEMPS COMING IN THE NEXT COUPLE DAYS WITH COLD FROPA
TOMORROW AND AGAIN THURSDAY NIGHT NOT ABLE TO TAP INTO ANYTHING
TOO COLD...WITH ARCTIC AIR REMAINING TRAPPED WELL TO OUR NORTH.
TEMPS WILL REMAIN NEAR MID DECEMBER NORMALS.
JKL
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
THE GOING FORECAST CONTINUES TO BE IN GOOD SHAPE...SO DECIDED TO
ONLY MAKE MINOR TWEAKS IN A FEW AREAS.
MAIN JET ENERGY STAYS WELL TO THE NORTH OF THE FORECAST AREA FOR
MOST OF THE EXTENDED PERIOD...KEEPING THE REALLY COLD AIR LOCKED
UP IN NORTHERN CANADA.
FRIDAY AND SATURDAY...A FAIRLY FLAT UPPER LEVEL RIDGE BUILDS INTO
THE REGION FROM THE WEST. WEAK SHORTWAVE ENERGY SLIDES EASTWARD
ALONG THE TOP OF THE RIDGE...BUT WITH A MAINLY DRY NW FLOW
ALOFT...THIS SHORTWAVE ENERGY IS ONLY EXPECTED TO GENERATE SOME
MID AND HIGH CLOUDS. AT THE SURFACE...WINDS WILL BE GUSTY ACROSS
THE WEST AS THE PRESSURE GRADIENT TIGHTENS FRIDAY INTO EARLY
SATURDAY IN RESPONSE TO HIGH PRESSURE BUILDING INTO IDAHO.
MODELS ARE IN DISAGREEMENT SUNDAY INTO MONDAY. MUCH LIKE
YESTERDAYS 12Z RUN THE ECMWF PUSHES A STRONG COLD FRONT WITH SNOW
SHOWERS THROUGH THE REGION SUNDAY INTO EARLY MONDAY...THEN A DRY
NW FLOW TAKES OVER. AT THE SAME TIME...THE GFS DOES NOT BRING THE
COLD FRONT IN UNTIL AFTER THE ECMWF...THEN DRIVES A SHORTWAVE WITH
WIDELY SCATTERED SNOW SHOWER ACTIVITY THROUGH THE REGION LATE
MONDAY. AGAIN TODAY...OPTED NOT TO REALLY CHANGE THE SUNDAY/MONDAY
FORECAST MUCH DUE TO THE MODEL DISCREPANCIES.
TUESDAY/TUESDAY NIGHT RIDGING BUILDS BACK IN FROM THE
WEST...KEEPING THE AREA DRY.
AS FAR AS TEMPERATURES ARE CONCERNED...THEY WILL STAY AT OR ABOVE
NORMAL FOR MOST OF THE EXTENDED PERIOD. TRENDED TOWARDS BETTER
PERFORMING TEMP GUIDANCE...BCCONSRAW AND BCCONSALL FOR DAYTIME HIGHS
AND CONSALL FOR OVERNIGHT LOWS. STC
&&
.AVIATION...
MVFR/IFR CONDITIONS WILL CONTINUE FROM KMLS EAST...DUE TO LOW
CEILINGS...INTO THE OVERNIGHT HOURS. WEST NORTHWEST WINDS WILL
PICK UP ACROSS THE EAST WEDNESDAY MORNING AS A FRONT PASSES.
KSHR...KBIL AND KLVM WILL REMAIN VFR THROUGH TONIGHT. INTERMITTENT
MVFR CONDITIONS IN LOW CEILINGS/SNOW SHOWERS WILL BE POSSIBLE FROM
WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FROM KSHR AND KBIL
WEST. GUSTY WINDS WILL BE POSSIBLE OVERNIGHT FROM KBIL WEST TO
KLVM. CHURCH/STC
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 025/038 021/033 019/034 021/045 027/045 024/038 021/038
02/J 12/S 31/B 00/U 01/B 21/B 11/U
LVM 023/037 025/033 017/035 016/044 022/044 020/039 015/037
02/J 13/S 41/B 00/N 12/J 22/J 11/B
HDN 015/038 016/033 015/035 015/042 021/045 020/039 016/040
02/J 12/S 31/B 00/U 01/B 22/J 11/B
MLS 015/033 011/028 017/031 017/039 021/041 021/034 017/035
02/J 12/S 41/B 00/B 01/B 11/B 11/B
4BQ 015/035 013/032 017/034 015/041 021/043 020/037 017/039
02/J 12/S 51/B 00/U 01/B 21/B 11/B
BHK 013/032 009/025 015/026 015/039 021/040 018/033 016/035
02/J 12/S 51/B 00/B 01/B 11/B 11/B
SHR 014/036 012/033 018/031 016/042 023/042 021/035 015/038
02/J 12/S 42/J 00/U 01/B 22/J 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1124 AM CST TUE DEC 13 2011
.AVIATION...18Z KGRI TAF. LIFR CONDITIONS TO CONTINUE THROUGH MUCH
OF THE CURRENT TAF PERIOD. STRATUS WITH CEILINGS NEAR 200FT AGL
AND VISIBILITY RESTRICTIONS NEAR 1/2SM IN FOG WILL PERSIST THROUGH
16Z WEDNESDAY. THE PASSAGE OF A SURFACE FRONT WILL ALLOW LOW LEVEL
DRY AIR ADVECTION TO INFILTRATE THE AREA TOWARDS THE END OF THE
TAF PERIOD...ALLOWING FOR IMPROVING VISIBILITIES AND RISING
CEILINGS...AS WELL AS A CHANGE IN LOW LEVEL WIND DIRECTION.
&&
.PREV DISCUSSION... /ISSUED 609 AM CST TUE DEC 13 2011/
SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER LONG/CHALLENGING
NIGHT...MOSTLY SPENT FINE TUNING HOURLY SURFACE TEMPERATURE
TRENDS DURING THE NEXT 12-18 HOURS...AND RESULTANT PRECIP TYPE
FOR THE ONGOING HEADLINES. LOCALLY DENSE FOG IS ALSO ADDING TO THE
ONGOING FUN.
THE SHORT STORY FOR TODAY IS THAT THE INHERITED WINTER WEATHER
ADVISORIES FOR LIGHT ICING/LIGHT FREEZING RAIN WERE LEFT LARGELY
UNCHANGED. ONLY TWEAKS WERE TO ADD FILLMORE COUNTY TO THE SEGMENT
THAT EXPIRES AT NOON...AND TO DROP ROOKS COUNTY GIVEN THAT NEARBY
AUTOMATED OBS CONFIRM THAT TEMPS IN THAT AREA ARE GENERALLY 33-37
DEGREES...AND SHOULDN/T DROP ANY FARTHER. OTHER COUNTIES ON THE
EXTREME SOUTHERN EDGE SUCH AS PHILLIPS/SMITH ARE LIKELY MARGINAL
AS WELL...BUT AT LEAST NORTHERN EDGES COULD PICK UP SOME LIGHT
FREEZING DRIZZLE AND WANTED TO KEEP THEM IN. AS
MENTIONED...LOCALLY DENSE TO NEAR-DENSE ALSO CONTINUES TO DEVELOP
ACROSS PARTS OF THE CWA...AND FORESEE THIS BECOMING MORE AND MORE
OF AN ISSUE DURING THE NEXT SEVERAL HOURS. ISSUED A STAND-ALONE
DENSE FOG ADVISORY FOR ROOKS COUNTY KS...BUT OPTED TO KEEP IT
SIMPLE FOR THE MAJORITY OF THE CWA AND INCLUDE FOG HAZARDS IN THE
TEXT OF THE WINTER WEATHER ADVISORIES. THE HANDFUL OF COUNTIES IN
THE SOUTHERN CWA STILL UNDER NO HEADLINE MAY ULTIMATELY NEED ADDED
TO A DENSE FOG HEADLINE IF THINGS WORSEN...BUT AT LEAST FOR NOW
THESE COUNTIES SEEM TO HAVE VISIBILITIES SAFELY ABOVE ADVISORY
CRITERIA.
SO...FOR THE MOST PART THINGS STARTING TO UNFOLD AS
EXPECTED...WITH AT LEAST PATCHY AREAS OF LIGHT DRIZZLE/FREEZING
DRIZZLE GETTING UNDERWAY PER RADAR RETURNS AND GROUND TRUTH HERE
AT THE WFO. HOWEVER...AM NOT AWARE OF ANY SIGNIFICANT IMPACTS YET
AT THIS TIME. MOVING FORWARD INTO THE DAY...CONFIDENCE IN SEEING
WIDESPREAD MEASURABLE PRECIP HAS WANED FROM 24 HOURS AGO GIVEN
LATEST TRENDS OF RUC/NAM/HRRR KEEPING MOST LEGITIMATE RAIN SOUTH
OF THE CWA. STILL...INCREASING LOW LEVEL ISENTROPIC LIFT SHOULD BE
MORE THAN SUFFICIENT FOR CONTINUED DEVELOPMENT OF FOG AND AT LEAST
TRACE DRIZZLE/FREEZING DRIZZLE FOR SEVERAL HOURS IN MOST AREAS.
TOTAL ICE ACCUMULATIONS WITHIN THE ADVISORY AREAS HAVE BEEN
TRIMMED A BIT...NOW RANGING FROM A TRACE ALONG THE SOUTHERN FRINGE
TO MAYBE 5 HUNDREDTHS OF AN INCH OR SO IN NORTHWEST COUNTIES.
SPENT A LOT OF TIME FINE TUNING SURFACE TEMP TRENDS...LEANING
HEAVILY ON THE RUC AND HOURLY GFS LAMP GUIDANCE. TRENDS ON THE
GRADUAL SOUTH TO NORTH WARMING ABOVE FREEZING HAVEN/T CHANGED MUCH
FROM PREVIOUS THINKING...AND AS A RESULT SAW NO REASON TO CHANGE
THE CURRENT BREAKDOWN OF THE WINTER WEATHER ADVISORY...WITH
SEVERAL COUNTIES SOUTHEAST OF A FULLERTON TO ALMA LINE LIKELY DONE
WITH ANY ICING THREAT BY NOON AT THE LATEST...WHILE NORTHWEST
COUNTIES REMAIN UNDER THE GUN WELL INTO THE AFTERNOON. AGAIN...NOT
LOOKING AT MUCH ICE ACCUMULATION..ESPECIALLY MEASURABLE...BUT
EASILY ENOUGH TO CAUSE PROBLEMS ON UNTREATED SURFACES.
AS FOR DENSE FOG/POTENTIALLY DENSE FOG...COULD EASILY FORESEE
ISSUES LASTING WELL INTO THE OVERNIGHT HOURS...AND WILL DEFER TO
DAY SHIFT TO POSSIBLY ISSUE/EXTEND FOG HEADLINES AS NEW TRENDS
EMERGE. FOR NOW...WANTED AS MUCH FOCUS AS POSSIBLE TO BE ON LIGHT
ICING CONCERNS. DIDN/T CHANGE HIGH TEMPS TODAY MUCH...AIMING FOR A
GRADIENT FROM LOW-MID 30S NORTHWEST TO LOW-MID 40S SOUTHEAST.
BETTER CHANCES FOR LEGITIMATE MEASURABLE RAIN ARRIVES TONIGHT AS
PRIMARY MID LEVEL SHORTWAVE APPROACHES FROM NEW MEXICO...AND UPPER
JET DYNAMICS/DIFFLUENCE INCREASE. KEPT POPS HIGH
TONIGHT...ESPECIALLY ACROSS THE SOUTHEAST 1/2 OR SO WITH 70-90
PERCENTS. ALTHOUGH NOT EXPECTING WIDESPREAD LIGHTNING STRIKES...AT
LEAST 100-200 J/KG MUCAPE APPEARS SUFFICIENT FOR AT LEAST ISOLATED
THUNDERSTORMS...AND LEFT THIS MENTION INTACT ACROSS GENERALLY THE
SOUTHEAST 1/2 OF THE CWA. PRONOUNCED CONTINUED LOW LEVEL WARM AIR
ADVECTION SHOULD ALLOW TEMPS TO SLOWLY RISE OVERNIGHT...AND ONLY
THE EXTREME NORTHWEST FRINGES OF THE CWA SHOULD REGISTER TEMPS AT
OR BELOW FREEZING FOR A FEW HOURS AFTER SUNSET. UNLESS SOMETHING
LINGERS FOR A FEW HOURS FAR NORTHWEST...ICING ISSUES SHOULD BE LARGELY
OVER BY DARK.
WEDNESDAY...THE 00Z ECMWF/GFS ARE IN DECENT AGREEMENT TRACKING THE
MAIN SHORTWAVE DIRECTLY ACROSS THE PLAINS...WITH A ROUGHLY 1006MB
SFC LOW CENTERED OVER NORTH CENTRAL KS AT 18Z BEFORE ZIPPING
NORTHEAST. A MID LEVEL DRY SLOT COULD BRING PRECIP TO A FAIRLY
EARLY END ESPECIALLY IN SOUTHWEST ZONES...AND HAVE TRENDED POPS
DOWN ACCORDINGLY DURING THE DAY. WHILE THUNDER WAS NOT INCLUDED
FOR THE DAYTIME HOURS...COULD SEE SOME INSTABILITY LURKING IN
PARTS OF THE AREA...AND A FEW RUMBLES NOT OUT OF THE QUESTION.
HAVE QUITE A HIGH TEMP GRADIENT IN PLACE...RANGING FROM MID 30S
AROUND ORD NEB...TO MID 50S NEAR BELOIT KS.
WED EVENING...PRECIP SHOULD COME TO A QUICK END IN THE EAST AS THE
WAVE DEPARTS...AND LINGERED A SLIGHT POP FOR RAIN/SNOW IN
NORTHEAST ZONES THROUGH MIDNIGHT...BUT ITS VERY POSSIBLE THAT
EVERYTHING IS ALREADY OVER BY 00Z. QUIET AND DRY CONDITIONS THEN
ANTICIPATED WED NIGHT THROUGH THURSDAY NIGHT...AS A SURFACE RIDGE
AXIS MOVES ACROSS THE AREA. KEPT HIGHS THURSDAY SIMILAR TO
PREVIOUS FORECAST WITH MOST PLACES BETWEEN 34-40. LOWERED LOWS
THURS NIGHT WITH EXPECTATION OF LIGHT WINDS/CLEAR SKIES...WITH
MOST AREAS AT LEAST DOWN INTO THE UPPER TEENS.
LONG TERM...12Z FRIDAY THROUGH MONDAY...A RELATIVELY QUIET WEATHER
PATTERN CONTINUES TO BE IN STORE FOR THE END OF THE WORK WEEK AS A
SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING
ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING WEATHER MAKER.
UNDER THIS PATTERN...NEAR ZONAL TO NORTHWESTERLY FLOW ALOFT WILL
CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS
AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN
DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE
EXTENDED WHEN THE LOW ACROSS THE DESERT SOUTHWEST EJECTS INTO THE
PLAINS. GLOBAL MODELS ARE BEGINNING TO COME INTO BETTER AGREEMENT
WITH THE HANDING OF THIS CUTOFF LOW PRESSURE SYSTEM...WITH THE LOCAL
AREA NOW EXPECTED TO BE JUST NORTHWEST OF THE TRAJECTORY OF THIS LOW
PRESSURE SYSTEM AS IT EJECTS INTO THE PLAINS EARLY NEXT
WEEK...ALBEIT GFS REMAINS SLIGHTLY FURTHER WEST WHICH COULD HAVE A
LARGE IMPACT ON LOCAL WEATHER. HOWEVER...SINCE GFS IS NOW TRENDING
CLOSER TO THE EUROPEAN...KEPT LOW POPS ACROSS THE AREA WHICH IS MORE
IN LINE WITH THE EC...AND KEPT A CHANCE OF BOTH RAIN AND SNOW AS
TEMPERATURE ALOFT INITIALLY WILL BE MORE FAVORABLE FOR RAIN...BUT
COOL DURING THE EVENT SUPPORTING A CHANCE FOR SOME SNOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039-
040-046-047-060-061-072-073-082.
DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NEZ039-040-
046-047-060>062-072>075-082>084.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ041-048-049-
062>064-074-075.
KS...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR KSZ005-017.
&&
$$
AVIATION...BRYANT
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
609 AM CST TUE DEC 13 2011
.SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER LONG/CHALLENGING
NIGHT...MOSTLY SPENT FINE TUNING HOURLY SURFACE TEMPERATURE
TRENDS DURING THE NEXT 12-18 HOURS...AND RESULTANT PRECIP TYPE
FOR THE ONGOING HEADLINES. LOCALLY DENSE FOG IS ALSO ADDING TO THE
ONGOING FUN.
THE SHORT STORY FOR TODAY IS THAT THE INHERITED WINTER WEATHER
ADVISORIES FOR LIGHT ICING/LIGHT FREEZING RAIN WERE LEFT LARGELY
UNCHANGED. ONLY TWEAKS WERE TO ADD FILLMORE COUNTY TO THE SEGMENT
THAT EXPIRES AT NOON...AND TO DROP ROOKS COUNTY GIVEN THAT NEARBY
AUTOMATED OBS CONFIRM THAT TEMPS IN THAT AREA ARE GENERALLY 33-37
DEGREES...AND SHOULDN/T DROP ANY FARTHER. OTHER COUNTIES ON THE
EXTREME SOUTHERN EDGE SUCH AS PHILLIPS/SMITH ARE LIKELY MARGINAL
AS WELL...BUT AT LEAST NORTHERN EDGES COULD PICK UP SOME LIGHT
FREEZING DRIZZLE AND WANTED TO KEEP THEM IN. AS
MENTIONED...LOCALLY DENSE TO NEAR-DENSE ALSO CONTINUES TO DEVELOP
ACROSS PARTS OF THE CWA...AND FORESEE THIS BECOMING MORE AND MORE
OF AN ISSUE DURING THE NEXT SEVERAL HOURS. ISSUED A STAND-ALONE
DENSE FOG ADVISORY FOR ROOKS COUNTY KS...BUT OPTED TO KEEP IT
SIMPLE FOR THE MAJORITY OF THE CWA AND INCLUDE FOG HAZARDS IN THE
TEXT OF THE WINTER WEATHER ADVISORIES. THE HANDFUL OF COUNTIES IN
THE SOUTHERN CWA STILL UNDER NO HEADLINE MAY ULTIMATELY NEED ADDED
TO A DENSE FOG HEADLINE IF THINGS WORSEN...BUT AT LEAST FOR NOW
THESE COUNTIES SEEM TO HAVE VISIBILITIES SAFELY ABOVE ADVISORY
CRITERIA.
SO...FOR THE MOST PART THINGS STARTING TO UNFOLD AS
EXPECTED...WITH AT LEAST PATCHY AREAS OF LIGHT DRIZZLE/FREEZING
DRIZZLE GETTING UNDERWAY PER RADAR RETURNS AND GROUND TRUTH HERE
AT THE WFO. HOWEVER...AM NOT AWARE OF ANY SIGNIFICANT IMPACTS YET
AT THIS TIME. MOVING FORWARD INTO THE DAY...CONFIDENCE IN SEEING
WIDESPREAD MEASURABLE PRECIP HAS WANED FROM 24 HOURS AGO GIVEN
LATEST TRENDS OF RUC/NAM/HRRR KEEPING MOST LEGITIMATE RAIN SOUTH
OF THE CWA. STILL...INCREASING LOW LEVEL ISENTROPIC LIFT SHOULD BE
MORE THAN SUFFICIENT FOR CONTINUED DEVELOPMENT OF FOG AND AT LEAST
TRACE DRIZZLE/FREEZING DRIZZLE FOR SEVERAL HOURS IN MOST AREAS.
TOTAL ICE ACCUMULATIONS WITHIN THE ADVISORY AREAS HAVE BEEN
TRIMMED A BIT...NOW RANGING FROM A TRACE ALONG THE SOUTHERN FRINGE
TO MAYBE 5 HUNDREDTHS OF AN INCH OR SO IN NORTHWEST COUNTIES.
SPENT A LOT OF TIME FINE TUNING SURFACE TEMP TRENDS...LEANING
HEAVILY ON THE RUC AND HOURLY GFS LAMP GUIDANCE. TRENDS ON THE
GRADUAL SOUTH TO NORTH WARMING ABOVE FREEZING HAVEN/T CHANGED MUCH
FROM PREVIOUS THINKING...AND AS A RESULT SAW NO REASON TO CHANGE
THE CURRENT BREAKDOWN OF THE WINTER WEATHER ADVISORY...WITH
SEVERAL COUNTIES SOUTHEAST OF A FULLERTON TO ALMA LINE LIKELY DONE
WITH ANY ICING THREAT BY NOON AT THE LATEST...WHILE NORTHWEST
COUNTIES REMAIN UNDER THE GUN WELL INTO THE AFTERNOON. AGAIN...NOT
LOOKING AT MUCH ICE ACCUMULATION..ESPECIALLY MEASURABLE...BUT
EASILY ENOUGH TO CAUSE PROBLEMS ON UNTREATED SURFACES.
AS FOR DENSE FOG/POTENTIALLY DENSE FOG...COULD EASILY FORESEE
ISSUES LASTING WELL INTO THE OVERNIGHT HOURS...AND WILL DEFER TO
DAY SHIFT TO POSSIBLY ISSUE/EXTEND FOG HEADLINES AS NEW TRENDS
EMERGE. FOR NOW...WANTED AS MUCH FOCUS AS POSSIBLE TO BE ON LIGHT
ICING CONCERNS. DIDN/T CHANGE HIGH TEMPS TODAY MUCH...AIMING FOR A
GRADIENT FROM LOW-MID 30S NORTHWEST TO LOW-MID 40S SOUTHEAST.
BETTER CHANCES FOR LEGITIMATE MEASURABLE RAIN ARRIVES TONIGHT AS
PRIMARY MID LEVEL SHORTWAVE APPROACHES FROM NEW MEXICO...AND UPPER
JET DYNAMICS/DIFFLUENCE INCREASE. KEPT POPS HIGH
TONIGHT...ESPECIALLY ACROSS THE SOUTHEAST 1/2 OR SO WITH 70-90
PERCENTS. ALTHOUGH NOT EXPECTING WIDESPREAD LIGHTNING STRIKES...AT
LEAST 100-200 J/KG MUCAPE APPEARS SUFFICIENT FOR AT LEAST ISOLATED
THUNDERSTORMS...AND LEFT THIS MENTION INTACT ACROSS GENERALLY THE
SOUTHEAST 1/2 OF THE CWA. PRONOUNCED CONTINUED LOW LEVEL WARM AIR
ADVECTION SHOULD ALLOW TEMPS TO SLOWLY RISE OVERNIGHT...AND ONLY
THE EXTREME NORTHWEST FRINGES OF THE CWA SHOULD REGISTER TEMPS AT
OR BELOW FREEZING FOR A FEW HOURS AFTER SUNSET. UNLESS SOMETHING
LINGERS FOR A FEW HOURS FAR NORTHWEST...ICING ISSUES SHOULD BE LARGELY
OVER BY DARK.
WEDNESDAY...THE 00Z ECMWF/GFS ARE IN DECENT AGREEMENT TRACKING THE
MAIN SHORTWAVE DIRECTLY ACROSS THE PLAINS...WITH A ROUGHLY 1006MB
SFC LOW CENTERED OVER NORTH CENTRAL KS AT 18Z BEFORE ZIPPING
NORTHEAST. A MID LEVEL DRY SLOT COULD BRING PRECIP TO A FAIRLY
EARLY END ESPECIALLY IN SOUTHWEST ZONES...AND HAVE TRENDED POPS
DOWN ACCORDINGLY DURING THE DAY. WHILE THUNDER WAS NOT INCLUDED
FOR THE DAYTIME HOURS...COULD SEE SOME INSTABILITY LURKING IN
PARTS OF THE AREA...AND A FEW RUMBLES NOT OUT OF THE QUESTION.
HAVE QUITE A HIGH TEMP GRADIENT IN PLACE...RANGING FROM MID 30S
AROUND ORD NEB...TO MID 50S NEAR BELOIT KS.
WED EVENING...PRECIP SHOULD COME TO A QUICK END IN THE EAST AS THE
WAVE DEPARTS...AND LINGERED A SLIGHT POP FOR RAIN/SNOW IN
NORTHEAST ZONES THROUGH MIDNIGHT...BUT ITS VERY POSSIBLE THAT
EVERYTHING IS ALREADY OVER BY 00Z. QUIET AND DRY CONDITIONS THEN
ANTICIPATED WED NIGHT THROUGH THURSDAY NIGHT...AS A SURFACE RIDGE
AXIS MOVES ACROSS THE AREA. KEPT HIGHS THURSDAY SIMILAR TO
PREVIOUS FORECAST WITH MOST PLACES BETWEEN 34-40. LOWERED LOWS
THURS NIGHT WITH EXPECTATION OF LIGHT WINDS/CLEAR SKIES...WITH
MOST AREAS AT LEAST DOWN INTO THE UPPER TEENS.
.LONG TERM...12Z FRIDAY THROUGH MONDAY...A RELATIVELY QUIET WEATHER
PATTERN CONTINUES TO BE IN STORE FOR THE END OF THE WORK WEEK AS A
SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING
ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING WEATHER MAKER.
UNDER THIS PATTERN...NEAR ZONAL TO NORTHWESTERLY FLOW ALOFT WILL
CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS
AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN
DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE
EXTENDED WHEN THE LOW ACROSS THE DESERT SOUTHWEST EJECTS INTO THE
PLAINS. GLOBAL MODELS ARE BEGINNING TO COME INTO BETTER AGREEMENT
WITH THE HANDING OF THIS CUTOFF LOW PRESSURE SYSTEM...WITH THE LOCAL
AREA NOW EXPECTED TO BE JUST NORTHWEST OF THE TRAJECTORY OF THIS LOW
PRESSURE SYSTEM AS IT EJECTS INTO THE PLAINS EARLY NEXT
WEEK...ALBEIT GFS REMAINS SLIGHTLY FURTHER WEST WHICH COULD HAVE A
LARGE IMPACT ON LOCAL WEATHER. HOWEVER...SINCE GFS IS NOW TRENDING
CLOSER TO THE EUROPEAN...KEPT LOW POPS ACROSS THE AREA WHICH IS MORE
IN LINE WITH THE EC...AND KEPT A CHANCE OF BOTH RAIN AND SNOW AS
TEMPERATURE ALOFT INITIALLY WILL BE MORE FAVORABLE FOR RAIN...BUT
COOL DURING THE EVENT SUPPORTING A CHANCE FOR SOME SNOW.
&&
.AVIATION...12Z KGRI TAF. POOR AVIATION CONDITIONS ARE EXPECTED AT
KGRI FOR AT LEAST THE NEXT 24 HOURS WITH PREVAILING IFR OR EVEN LIFR
CIGS AND VISIBILITIES EXPECTED. LOW STRATUS...SOME FOG...AND
FREEZING DRIZZLE ARE ALL EXPECTED AT TIMES THROUGH AROUND
13/18Z...BEFORE TEMPERATURES WARM A FEW DEGREES AND -FZDZ
TRANSISTORS TO -DZ. WINDS WILL GENERALLY REMAIN LIGHT AND FROM THE
SOUTH THROUGHOUT THE PERIOD. INSTABILITY INCREASE LATE TONIGHT...BUT
THINK ANY THUNDERSTORMS THAT DO DEVELOP WILL REMAIN SOUTH OF
KGRI...AND DID NOT MENTION A CB OR -TSRA IN TAF AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ041-048-049-
062>064-074>077-083>085.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039-
040-046-047-060-061-072-073-082.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR KSZ005-006.
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR KSZ017.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
941 AM CST TUE DEC 13 2011
.DISCUSSION...
LIGHT FREEZING DRIZZLE HAVE LEFT AREA ROADWAYS WEST OF I-29 SLICK
OVERNIGHT. INCREASING THETA-E ADVECTION AND 800 MB MOISTURE
TRANSPORT LATE THIS MORNING INTO THIS AFTERNOON IS SOMEWHAT
CONCERNING...AS DENDRITIC LAYER REMAINS UNSATURATED SO PRECIPITATION
WOULD LIKELY FALL AS ADDITIONAL DRIZZLE. HAVE MADE CALLS ACROSS
WESTERN CWA IN VICINITY OF DEVELOPING RADAR ECHOS...BUT NOTHING
REACHING THE GROUND AT THIS POINT. HRRR SHOWS RELATIVELY LITTLE
ACROSS THE FORECAST AREA THROUGH 00Z WITH THE FOCUS FURTHER TO THE
SOUTH ACROSS EASTERN KANSAS...NORTHERN MISSOURI... AND SOUTHERN IOWA
ALONG THE 850 MB FRONT. KVTL REPORTED FREEZING RAIN AT THE TOP OF
THE HOUR. IF PRECIPITATION IS ABLE TO DEVELOP ACROSS WESTERN
PORTIONS OF THE FORECAST AREA...WILL ISSUE AN ADVISORY EVEN THOUGH
THE PRECIPITATION IS EXPECTED TO BE FAIRLY LIGHT IT WOULD STILL
SIGNIFICANTLY IMPACT TRAVEL SINCE IT WOULD BE ICE. SURFACE
TEMPERATURES ARE EXPECTED TO WARM THROUGHOUT THE DAY...AND SHOULD BE
MAINLY ABOVE FREEZING IN MOST LOCATIONS BY EARLY TO MID EVENING
MAKING THE LIQUID PRECIPITATION LESS OF AN ISSUE.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
IFR CEILINGS WITH MAINLY MVFR VISIBILITIES EXPECTED THROUGH THE
MORNING. CEILINGS MAY IMPROVE TO LOW MVFR THIS AFTERNOON...BUT THE
SHOULD LOWER BACK INTO IFR THIS EVENING. MIXED PRECIPITATION WILL
LIFT NORTH THIS AFTERNOON AND SPREAD ACROSS THE AREA. MAINLY RAIN IS
ANTICIPATED AT KSUX WHILE KFSD COULD SEE A BRIEF PERIOD OF -SN
BEFORE CHANGING TO ALL RAIN. BOTH LOCATIONS SHOULD GO TO IFR OR
POSSIBLY LIFR LATER TONIGHT IN -DZ...BR AND PATCHY LIGHT RAIN. KHON
MAY HAVE THE MOST PROBLEMS WITH A MIX OF FREEZING RAIN...LIGHT SNOW
AND RAIN AT TIMES.
&&
.DISCUSSION.../ISSUED AT 359 AM CST/
SOCKED IN WITH STRATUS AND LIGHT FOG THROUGH MUCH OF THE DAY AS
LIGHT WINDS GRADUALLY BECOME SOUTHEAST. NO REAL CHANCE FOR ESCAPE
FROM THE STRATUS SO HAVE SLOWED THE DIURNAL CLIMB IN THE MORNING A
BIT...BRINGING MORE OF A RISE IN THE AFTERNOON AS THE WARMER LOW
LEVEL THERMAL FIELD BUILDS NORTH. UPPER LEVEL SUPPORT AND INCREASING
MID TO UPPER LEVEL MOISTURE WILL BRING A VERY GOOD CHANCE FOR
PRECIPITATION THIS AFTERNOON AND OVERNIGHT. THE REAL QUESTION WILL
BE PRECIPITATION TYPE...WHICH WILL BE QUITE VARIABLE ACROSS THE CWA.
MOST OF NORTHWEST IOWA CAN EXPECT RAIN WITH LITTLE CHANCE OF
ANYTHING ELSE. SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA WILL
LIKELY SEE A BRIEF PERIOD OF MIXED PRECIPITATION WITH SNOW THE
LIKELY PRECIPITATION TYPE BEFORE QUICKLY CHANGING TO RAINFALL. THE
AREA MOST AT RISK WILL BE CENTRAL SOUTH DAKOTA WHERE THERMAL FIELDS
RIDE RIGHT AROUND TO 0 DEGREE ISOTHERM FROM ABOUT 800MB TO THE
SURFACE...WHICH LEAVES MUCH TO THE IMAGINATION WHEN TRYING TO
DETERMINE PRECIPITATION TYPE. FOR NOW WILL GO WITH A MIX OF FREEZING
RAIN AND SNOW...BUT CENTRAL SOUTH DAKOTA IS ALSO THE LOCATION LEAST
LIKELY TO GET ANY HEAVIER PRECIPITATION...SO ONLY EXPECTING A COUPLE
OF HUNDRETHS. HOWEVER...IF THIS FALLS AS MAINLY FREEZING RAIN THAT
WILL LIKELY BE ENOUGH TO CAUSE PROBLEMS. WILL NOT ISSUE AN ADVISORY
AT THIS TIME AS CONFIDENCE JUST NOT QUITE THERE...BUT SOMEWHERE FROM
ABOUT GREGORY TO BRULE TO CHARLES MIX COUNTY WILL BE THE HIGHEST
THREAT AREA FOR ANY ADVISORY TYPE PRECIPITATION. HIGHS MAINLY IN THE
30S TODAY.
FAIRLY STEADY TEMPERATURES TONIGHT AS A STRONG TROUGH DIGS TO THE
WEST AND SOUTHERLY FLOW ENHANCES. THIS WILL BRING A MAINLY RAIN
THREAT TO THE AREA WITH THE BEST CHANCE FOR A MIX OF PRECIPITATION
FROM CENTRAL SOUTH DAKOTA DOWN HIGHWAY 14. BUT WITH TEMPERATURES
ONLY A COUPLE OF DEGREES FROM GOING ABOVE FREEZING COULD EASILY END
UP AS MAINLY RAIN. UPPER LEVEL SUPPORT SURGES NORTHWARD AND HANGS
AROUND THROUGH THE DAY ON WEDNESDAY. SO...MORE CLOUDS...MAINLY
RAINFALL OVER THE EAST AND DECREASING CHANCES FOR PRECIPITATION
ACROSS THE WEST. AS THE WAVE PASSES WILL SEE SOME COLDER AIR FILTER
IN SO COULD BRIEFLY MIX WITH SNOW AS THE SYSTEM EXITS. NEEDLESS TO
SAY THE DIURNAL RANGE ON WEDNESDAY WILL BE MINIMAL WITH CLOUDS AND
PRECIPITATION IN PLACE. OVERALL FOR TUESDAY NIGHT INTO WEDNESDAY
ONLY EXPECTING A FEW HUNDRETHS OF LIGHT FREEZING RAIN POTENTIAL IN
SOUTH CENTRAL SOUTH DAKOTA LATE THIS AFTERNOON INTO THIS EVENING
WITH SNOW AMOUNTS GENERALLY LESS THAN AN INCH. RAINFALL AMOUNTS
COULD APPROACH A HALF AN INCH ACROSS NORTHWEST IOWA WHICH STAYS IN
THE WARM AND MOIST FLOW THE LONGEST. /08
FOR THE MOST PART...THE SIGNIFICANT FRONTAL DYNAMICS WILL WEAKEN
FAIRLY QUICKLY AND PULL EASTWARD DURING THE EVENING HOURS. BODILY
COOLING OF THE AIRMASS WOULD SUGGEST A RAIN TO SNOW TRANSITION
PULLING EAST...WITH PERHAPS SOME HELP OF DIURNAL CYCLE AND INTENSITY
IN BAND HELPING TO CHANGE OVER A BIT QUICKER. PERHAPS A QUICK HALF
INCH TO INCH OF SNOW THROUGH SOUTHWEST MINNESOTA AND HIGHEST
LOCATIONS OF NORTHWEST IOWA DURING THE EARLY EVENING.
LIKELY THAT BEYOND A NOMINAL LINGERING CHANCE IN THE FAR EAST...
LACK OF DYNAMICS BY 06Z SHOULD ELIMINATE MEASURABLE PRECIPITATION
THE REMAINDER OF THE NIGHT. AS RIDGE BUILDS IN FROM
WEST...INCREASING GRADIENT WILL MAKE FOR A BREEZY NIGHT ACROSS THE
AREA...AND MIXING KEEPING TEMPS FROM PLUMMETING TOO MUCH AS STRONGER
COLD AIR ADVECTION OCCURS LAST NIGHT
THURSDAY A WINDY AND COOLER DAY...WITH WINDS DROPPING SHARPLY TOWARD
SUNSET AS SURFACE RIDGE AXIS NOSES THROUGH THE SOUTH DAKOTA CWA AND
EXPANDS EAST THROUGH THE NIGHT. INCREASE IN CLOUDS WILL KEEP WESTERN
AND NORTHERN AREAS FROM DROPPING TOO SHARPLY IN THE WEAK FLOW...BUT
MORE EXPOSED SOUTHEAST COULD EASILY OUTDO GUIDANCE BY A FEW DEGREES
AND CLOSER TO BIAS CORRECTED VALUES SEEMS THE WAY TO HEDGE.
FRIDAY WILL FEATURE WAVE IN NORTHERN STREAM WITH MOST QG DYNAMICS
ZIPPING THROUGH NORTHERN HALF OF AREA. AIRMASS IN PLACE WILL BE
QUITE DRY IN LOW LEVELS...SO IS REALLY SLIGHT 850-700 WARM AIR
ADVECTION/FRONTOGENESIS THAT FAVORS A SMALL POP MOVING THROUGH THE
NORTHERN CWA. CARRIED SLIGHTLY BETTER CHANCE IN THE AFTERNOON IN
SOUTHWEST MINNESOTA AS EVOLUTION OF SYSTEM WILL ALLOW SATURATION
FROM ALOFT IN VICINITY OF MID LEVEL FRONTAL BOUNDARY.
CONTINUED SPLIT FLOW ALOFT IS NOT DOING PREDICTABILITY ANY FAVORS IN
THE EXTENDED RANGE. GFS/ECMWF/CANADIAN ALL PAINTING QUITE DIFFERENT
SCENARIOS FOR THE WEEKEND AND MONDAY...ESPECIALLY THE GFS SYSTEM ON
MONDAY...WHICH DOES NOT REALLY FIT IN WELL WITH THE ENSEMBLES WHICH
ARE MORE SPLIT FEATURED...AND LIKEWISE ECMWF SIMILAR SYSTEM IS
SLOWER BY A DAY OR SO AND MUCH FURTHER SOUTH. UNCERTAINTY DOES NOT
SUGGEST ENOUGH CONFIDENCE TO GROSSLY ALTER EXTENDED. HOWEVER...
PATTERN GOING INTO THE WEEKEND IS LOOSELY MATCHED TO THAT WHICH
RESULTED IN MUCH WARMER THAN PREDICTED TEMPERATURES FOR SATURDAY AND
SUNDAY. POTENTIAL OF JUST AN INCH OR LESS SNOW AND SOME LIGHT ICING
COULD STILL IMPACT TEMPERATURES A BIT...SO DID NOT GET OUT OF
CONTROL WITH WARMING...BUT DID ATTEMPT TO GET SOMEWHAT A WARMER
PICTURE... ESPECIALLY DOWNSTREAM OF BUFFALO RIDGE AND BACK IN HIGHER
TERRAIN OF SOUTH CENTRAL. IF THERE IS TO BE ANY PRECIPITATION BY
MONDAY...WHICH REMAINS QUITE A BIT IN DOUBT...THERMAL PROFILES WOULD
ALMOST CERTAINLY TAKE SNOW OUT OF THE MIX UNTIL LATE IN EVENT WITH
+2 TO +6C 850 HPA AIRMASS...MORE OF A RAIN/FREEZING RAIN SETUP
CHANGING TO SNOW AS SYSTEM UNDERGOES DYNAMIC COOLING. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1224 PM CST TUE DEC 13 2011
.UPDATE...
BNA STILL DOWN BELOW 1SM AT THIS HOUR. WILL EXTEND THE DRIZZLE AND
FOG INTO THE AFTERNOON. DESPITE THE RADAR RETURN...PRECIP AMOUNTS
ARE VERY LIGHT ACROSS THE NW. WILL THEREFORE KEEP THE POPS WHERE
THEY ARE. OTW...TEMPS AND WINDS ARE ON TRACK. UPDATE OUT
SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 827 AM CST TUE DEC 13 2011/
UPDATE...
WEAK DISTURBANCE MOVING OVER MO AND WESTERN KY IS EXTENDING A BIT
FURTHER SE THAN THE MODELS HAVE INDICATED. WE DO HAVE REPORTS OF
DRIZZLE AND FOG ACROSS THE AREA. THE LATEST RUC SHOWS THE SLIGHT
POTENTIAL FOR MEASURABLE RAINFALL ACROSS OUR NW COUNTIES TODAY.
FURTHERMORE...CANNOT DISCOUNT THE 50 POP FOR CKV FROM THE MET.
WILL GO AHEAD AND UPDATE THE GRIDS AND INTRODUCE A LOW CHANCE OF
SHOWERS FOR OUR NW COUNTIES FOR TODAY. OTW...REMAINDER OF FCST IS
OK AS THE DRIZZLE AND FOG SHOULD CONTINUE THIS MORNING.
UPDATE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 634 AM CST TUE DEC 13 2011/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
SURFACE HIGH CENTERED OVER EASTERN OHIO THIS MORNING WITH STRONG UPPER
RIDGE BUILDING EASTWARD FROM MISSISSIPPI VALLEY.
GOOD ISENTROPIC LIFT ON 290 KELVIN SURFACE WORKING AROUND PERIPHERY
OF UPPER RIDGE EVIDENT IN LATEST MOSAIC LOOP AS LIGHT RAIN HAS
SPREAD INTO FAR WESTERN KY/TN AT DAYBREAK. BEST LIFT WILL REMAIN
WEST AND NORTH OF MY CWA TODAY. FOG...AND LOW CEILINGS WILL SHOW
IMPROVEMENT AS WE GO THROUGH THE MORNING AT BNA BECOMING VFR
DURING AFTERNOON WITH A RETURN LATE NIGHT. AT CSV FOG AND LOW
CEILINGS WILL IMPROVE BUT SLOWLY BECOMING VFR BY EARLY TO MID-
AFTERNOON BEFORE RETURNING TO IFR CONDITIONS DURING THE EVENING
AND CONTINUING OVERNIGHT.
BOYD
PREV DISCUSSION... /ISSUED 308 AM CST TUE DEC 13 2011/
DISCUSSION...
CLOUDY FOGGY NIGHT ACROSS THE MID STATE WITH A FEW AREAS REPORTING
SOME DENSE FOG AND EVEN SOME PATCHES OF DRIZZLE OCCURRING.
DESPITE THE CLOUDS AND FOG...SURFACE OBS SHOW TEMPERATURES IN THE
40S WHICH ARE AROUND 20 DEGREES WARMER THAN THIS TIME YESTERDAY.
THIS IS THE BEGINNING OF A PERIOD OF NEAR TO ABOVE NORMAL
TEMPERATURES WHICH WILL CONTINUE FOR AT LEAST THE NEXT WEEK.
FEW CHANGES HAVE BEEN MADE TO OVERALL FORECAST AS GUIDANCE
CONTINUES TO HAVE A GOOD CONSENSUS ON UPCOMING PATTERN. WATER
VAPOR IMAGERY SHOWS OUR NEXT WEATHER MAKER IN THE FORM OF AN
UPPER LEVEL LOW OFF THE SOUTHERN CALIFORNIA COAST. THIS SYSTEM IS
EXPECTED TO OPEN INTO A POSITIVELY TILTED TROUGH WHICH WILL ENTER
THE PLAINS ON WEDNESDAY AND REACH OUR REGION ON THURSDAY. AHEAD OF
THE SYSTEM...INCREASING WAA REGIME ALONG WITH WEAK RIDGING ALOFT
WILL ALLOW FOR A CONTINUED WARMING TREND TODAY INTO TOMORROW.
TEMPS WILL BE TEMPERED SOMEWHAT PER FORECAST SOUNDINGS AND TIME
HEIGHT PLOTS AS A STRONG INVERSION AROUND 850MB TRAPS LOW CLOUDS
OVER THE MID STATE TODAY...AND THICK CIRRUS MOVES OVER THE MID
STATE ON WEDNESDAY. NEVERTHELESS...HIGHS LOOK TO WARM INTO THE 50S
AREA WIDE TODAY AND WELL INTO THE 60S ON WEDNESDAY.
GFS/NAM/ECMWF IN EXCELLENT AGREEMENT ON AFOREMENTIONED TROUGH
FORCING A COLD FRONT INTO THE NORTHWESTERN CWA BETWEEN 06-12Z
WEDNESDAY NIGHT WHICH WILL MOVE ACROSS THE ENTIRE CWA ON
THURSDAY...WITH WIDESPREAD SHOWERS EXPECTED. ADDED A MENTION OF
TSTORMS AS FORECAST SOUNDINGS SHOW K INDEX VALUES RISING INTO THE
MID 30S AND SOME WEAK ELEVATED INSTABILITY...ALTHOUGH MAJORITY OF
PRECIP WILL JUST BE SHOWERS. FRONT MOVES JUST SOUTH OF CWA AS A
SECONDARY WAVE MOVES ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY...BRINGING A SECOND ROUND OF RAIN TO ALL ZONES. DESPITE
FORECAST AREA BEING IN A POST FRONTAL AIRMASS...THERMAL PROFILES
WILL BE TOO WARM TO SUPPORT ANYTHING OTHER THAN RAIN.
AFTER PRECIP ENDS FRIDAY NIGHT...A BRIEF COOLDOWN WILL OCCUR OVER
THE WEEKEND WITH TEMPS FALLING BACK TO NEAR NORMAL LEVELS. GLOBAL
MODELS THEN DEPICT A SIMILAR SYSTEM AFFECTING THE MID STATE AGAIN
MONDAY AND TUESDAY OF NEXT WEEK WITH TEMPS WARMING ABOVE NORMAL
AND A COLD FRONT BRINGING ANOTHER ROUND OF SHOWERS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
827 AM CST TUE DEC 13 2011
.UPDATE...
WEAK DISTURBANCE MOVING OVER MO AND WESTERN KY IS EXTENDING A BIT
FURTHER SE THAN THE MODELS HAVE INDICATED. WE DO HAVE REPORTS OF
DRIZZLE AND FOG ACROSS THE AREA. THE LATEST RUC SHOWS THE SLIGHT
POTENTIAL FOR MEASURABLE RAINFALL ACROSS OUR NW COUNTIES TODAY.
FURTHERMORE...CANNOT DISCOUNT THE 50 POP FOR CKV FROM THE MET.
WILL GO AHEAD AND UPDATE THE GRIDS AND INTRODUCE A LOW CHANCE OF
SHOWERS FOR OUR NW COUNTIES FOR TODAY. OTW...REMAINDER OF FCST IS
OK AS THE DRIZZLE AND FOG SHOULD CONTINUE THIS MORNING.
UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 634 AM CST TUE DEC 13 2011/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
SURFACE HIGH CENTERED OVER EASTERN OHIO THIS MORNING WITH STRONG UPPER
RIDGE BUILDING EASTWARD FROM MISSISSIPPI VALLEY.
GOOD ISENTROPIC LIFT ON 290 KELVIN SURFACE WORKING AROUND PERIPHERY
OF UPPER RIDGE EVIDENT IN LATEST MOSAIC LOOP AS LIGHT RAIN HAS
SPREAD INTO FAR WESTERN KY/TN AT DAYBREAK. BEST LIFT WILL REMAIN
WEST AND NORTH OF MY CWA TODAY. FOG...AND LOW CEILINGS WILL SHOW
IMPROVEMENT AS WE GO THROUGH THE MORNING AT BNA BECOMING VFR
DURING AFTERNOON WITH A RETURN LATE NIGHT. AT CSV FOG AND LOW
CEILINGS WILL IMPROVE BUT SLOWLY BECOMING VFR BY EARLY TO MID-
AFTERNOON BEFORE RETURNING TO IFR CONDITIONS DURING THE EVENING
AND CONTINUING OVERNIGHT.
BOYD
PREV DISCUSSION... /ISSUED 308 AM CST TUE DEC 13 2011/
DISCUSSION...
CLOUDY FOGGY NIGHT ACROSS THE MID STATE WITH A FEW AREAS REPORTING
SOME DENSE FOG AND EVEN SOME PATCHES OF DRIZZLE OCCURRING.
DESPITE THE CLOUDS AND FOG...SURFACE OBS SHOW TEMPERATURES IN THE
40S WHICH ARE AROUND 20 DEGREES WARMER THAN THIS TIME YESTERDAY.
THIS IS THE BEGINNING OF A PERIOD OF NEAR TO ABOVE NORMAL
TEMPERATURES WHICH WILL CONTINUE FOR AT LEAST THE NEXT WEEK.
FEW CHANGES HAVE BEEN MADE TO OVERALL FORECAST AS GUIDANCE
CONTINUES TO HAVE A GOOD CONSENSUS ON UPCOMING PATTERN. WATER
VAPOR IMAGERY SHOWS OUR NEXT WEATHER MAKER IN THE FORM OF AN
UPPER LEVEL LOW OFF THE SOUTHERN CALIFORNIA COAST. THIS SYSTEM IS
EXPECTED TO OPEN INTO A POSITIVELY TILTED TROUGH WHICH WILL ENTER
THE PLAINS ON WEDNESDAY AND REACH OUR REGION ON THURSDAY. AHEAD OF
THE SYSTEM...INCREASING WAA REGIME ALONG WITH WEAK RIDGING ALOFT
WILL ALLOW FOR A CONTINUED WARMING TREND TODAY INTO TOMORROW.
TEMPS WILL BE TEMPERED SOMEWHAT PER FORECAST SOUNDINGS AND TIME
HEIGHT PLOTS AS A STRONG INVERSION AROUND 850MB TRAPS LOW CLOUDS
OVER THE MID STATE TODAY...AND THICK CIRRUS MOVES OVER THE MID
STATE ON WEDNESDAY. NEVERTHELESS...HIGHS LOOK TO WARM INTO THE 50S
AREA WIDE TODAY AND WELL INTO THE 60S ON WEDNESDAY.
GFS/NAM/ECMWF IN EXCELLENT AGREEMENT ON AFOREMENTIONED TROUGH
FORCING A COLD FRONT INTO THE NORTHWESTERN CWA BETWEEN 06-12Z
WEDNESDAY NIGHT WHICH WILL MOVE ACROSS THE ENTIRE CWA ON
THURSDAY...WITH WIDESPREAD SHOWERS EXPECTED. ADDED A MENTION OF
TSTORMS AS FORECAST SOUNDINGS SHOW K INDEX VALUES RISING INTO THE
MID 30S AND SOME WEAK ELEVATED INSTABILITY...ALTHOUGH MAJORITY OF
PRECIP WILL JUST BE SHOWERS. FRONT MOVES JUST SOUTH OF CWA AS A
SECONDARY WAVE MOVES ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY...BRINGING A SECOND ROUND OF RAIN TO ALL ZONES. DESPITE
FORECAST AREA BEING IN A POST FRONTAL AIRMASS...THERMAL PROFILES
WILL BE TOO WARM TO SUPPORT ANYTHING OTHER THAN RAIN.
AFTER PRECIP ENDS FRIDAY NIGHT...A BRIEF COOLDOWN WILL OCCUR OVER
THE WEEKEND WITH TEMPS FALLING BACK TO NEAR NORMAL LEVELS. GLOBAL
MODELS THEN DEPICT A SIMILAR SYSTEM AFFECTING THE MID STATE AGAIN
MONDAY AND TUESDAY OF NEXT WEEK WITH TEMPS WARMING ABOVE NORMAL
AND A COLD FRONT BRINGING ANOTHER ROUND OF SHOWERS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
835 PM CST WED DEC 14 2011
.UPDATE...
THE RAIN HAS ENDED FOR TONIGHT ALONG AND WEST OF A SHERMAN...FORT
WORTH...COMANCHE LINE. TO THE WEST OF THIS LINE WINDS HAVE BECOME
SOUTHWEST TO WEST. WINDS WILL COME AROUND TO THE NORTHWEST AND NORTH
OVERNIGHT INTO THURSDAY MORNING AS A COLD FRONT MOVES THROUGH THE
REGION. NO CHANGES WERE MADE TO THE TOMORROW ONWARD FORECAST...AS
AN APPROACHING SHORTWAVE THURSDAY WILL RESULT IN RAIN DEVELOPING
AREAWIDE. HAVE ADJUSTED THE REST OF THE EVENING/OVERNIGHT
POPS/WEATHER/QPF FOR ONGOING TRENDS.
58
&&
.AVIATION...
DFW TERMINALS...SHOWERS AND ISOLATED THUNDERSTORMS ARE MOVING
THROUGH THE DFW METROPLEX AT THIS TIME. THESE STORMS WILL SLOWLY
CLEAR THE TERMINALS FROM WEST TO EAST BY 15/03Z OR 9 PM CST.
WEST-SOUTHWEST TO SOUTHWEST WINDS WILL PREVAIL BEHIND THE LINE
WITH CIGS IMPROVING TO AROUND 4 KFT. AROUND MIDNIGHT OR
06Z...WINDS WILL SHIFT TO THE WEST AND THEN THE COLD FRONT WILL
ARRIVE AROUND 11Z OR 5 AM WITH THE WINDS SHIFTING TO THE NORTH-
NORTHWEST. ON THURSDAY...ANOTHER UPPER LEVEL TROUGH WILL APPROACH
THE REGION BRINGING ADDITIONAL LIFT TO NORTH TEXAS. THIS
ADDITIONAL LIFT WILL COMBINE WITH WARM AIR OVERRUNNING THE SHALLOW
COLD FRONT AND ADDITIONAL LIGHT RAIN AND SHOWERS WILL DEVELOP...
POSSIBLY IN THE AFTERNOON BUT MORE LIKELY IN THE LATE
AFTERNOON/EARLY EVENING HOURS.
KACT...SCATTERED LIGHT RAIN WILL LIKLEY CONTINUE WELL INTO THE
NIGHT AHEAD OF AN APPROACHING COLD FRONT. CEILINGS WILL BE THE
MAIN CHALLENGE TONIGHT AS CIGS CURRENTLY VARY FROM LOW MVFR TO
VFR AROUND THE AIRPORT. THINK THAT CEILINGS WILL PREVAIL IN MVFR
FOR MUCH OF THE NIGHT WITH WARM AIR ADVECTION CONTINUING. COLD
FRONT WILL ARRIVE AROUND 11Z OR 5 AM WITH THE WINDS SHIFTING TO
THE NORTH. THIS WILL LIKELY CLEAR OUT THE RAIN FOR AT LEAST A FEW
HOURS. ON THURSDAY...ANOTHER UPPER LEVEL TROUGH WILL APPROACH THE
REGION BRINGING ADDITIONAL LIFT TO NORTH TEXAS. THIS ADDITIONAL
LIFT WILL COMBINE WITH WARM AIR OVERRUNNING THE SHALLOW COLD FRONT
AND ADDITIONAL LIGHT RAIN AND SHOWERS WILL DEVELOP IN THE
AFTERNOON. THERE IS A SLIGHT CHANCE THAT THE NEXT ROUND OF RAIN
MAY BEGIN IN THE LATE MORNING HOURS.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 331 PM CST WED DEC 14 2011/
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS NORTH
TEXAS THIS AFTERNOON AS A PACIFIC COLD FRONT MOVES EAST. THE UPPER
LEVEL SYSTEM RESPONSIBLE FOR DEEP LAYER ASCENT IS SHEARING OUT
ACROSS THE SOUTHERN PLAINS AND WILL MOVE NORTHEAST THIS EVENING
ALLOWING THE FRONTAL BOUNDARY TO SLOW DOWN AS IT MOVES EAST.
LATEST RUC SOUNDINGS AND LOCALLY DERIVED CONVECTIVE PARAMETERS
INDICATE THAT 700MB WARM NOSE HAS MOSTLY ERODED WITH ONLY WEAK
INHIBITION PRESENT IN VICINITY OF THE FRONT. ANYWHERE FROM
500-700J/KG OF INSTABILITY REMAINS PRESENT AND WILL SUPPORT
THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING INTO TONIGHT.
OVERALL SEVERE WEATHER THREAT IS LOW BUT SOME HAIL WILL REMAIN
POSSIBLE. FRONT WILL DRIFT SOUTH AND EAST LATER TONIGHT WITH
PRECIP TAPERING FROM WEST TO EAST.
ALTHOUGH SURFACE FRONT WILL BE SOUTH OF THE AREA ON THURSDAY AMPLE
MOISTURE WILL RIDE ATOP THE SHALLOW COOLER AIR. REMNANTS OF THE
UPPER LOW OVER THE SOUTHWEST IS EXPECTED TO EJECT NORTHEAST DURING
THE DAY TOMORROW. THIS SYSTEM SHOULD PROVIDE SUFFICIENT FORCING TO
LIFT MOISTURE IN THE 850-700MB LAYER. ELEVATED INSTABILITY WILL BE
WEAK ALTHOUGH IT SHOULD BE SUFFICIENT FOR SHOWERY TYPE PRECIP TO
DEVELOP EVEN THOUGH THE NEAR SURFACE LAYER WILL BE DRY. MODEL
GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION AND HAVE RAISED
POPS FOR THU/THU NIGHT ACROSS NORTH TEXAS.
FRIDAY AND SATURDAY STILL LOOK LIKE THE QUIETEST DAYS THROUGH THE
NEXT SEVERAL WITH MOST AREAS STAYING DRY. THE NEXT STRONG SYSTEM
IS EXPECTED TO MOVE OUT OF THE SOUTHWEST US BY SUNDAY. MOISTURE
WILL SURGE NORTHWARD AHEAD OF THIS UPPER LOW...WHICH IS FORECAST
TO REMAIN CLOSED AS IT MOVES ACROSS NORTH TEXAS. THIS SYSTEM
CONTINUES TO LOOK MORE POTENT AND AGAIN WE MAY SEE SOME
SIGNIFICANT RAINFALL AS IT MOVES THROUGH. WILL HAVE TO MONITOR FOR
SEVERE WEATHER POTENTIAL AS WE GET CLOSER TO THE EVENT.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 54 56 40 54 38 / 30 50 70 10 10
WACO, TX 58 58 42 53 42 / 60 60 70 20 20
PARIS, TX 55 57 39 51 37 / 90 40 70 20 10
DENTON, TX 51 54 38 51 33 / 20 40 70 10 10
MCKINNEY, TX 54 56 41 52 36 / 40 40 70 20 10
DALLAS, TX 55 58 41 54 41 / 40 50 70 20 10
TERRELL, TX 57 59 42 52 40 / 90 50 70 20 10
CORSICANA, TX 59 62 45 54 42 / 70 60 70 30 20
TEMPLE, TX 59 59 42 53 43 / 60 70 70 20 20
MINERAL WELLS, TX 48 52 37 50 35 / 10 40 60 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/58
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
559 PM CST WED DEC 14 2011
.AVIATION...
DFW TERMINALS...SHOWERS AND ISOLATED THUNDERSTORMS ARE MOVING
THROUGH THE DFW METROPLEX AT THIS TIME. THESE STORMS WILL SLOWLY
CLEAR THE TERMINALS FROM WEST TO EAST BY 15/03Z OR 9 PM CST.
WEST-SOUTHWEST TO SOUTHWEST WINDS WILL PREVAIL BEHIND THE LINE
WITH CIGS IMPROVING TO AROUND 4 KFT. AROUND MIDNIGHT OR
06Z...WINDS WILL SHIFT TO THE WEST AND THEN THE COLD FRONT WILL
ARRIVE AROUND 11Z OR 5 AM WITH THE WINDS SHIFTING TO THE NORTH-
NORTHWEST. ON THURSDAY...ANOTHER UPPER LEVEL TROUGH WILL APPROACH
THE REGION BRINGING ADDITIONAL LIFT TO NORTH TEXAS. THIS
ADDITIONAL LIFT WILL COMBINE WITH WARM AIR OVERRUNNING THE SHALLOW
COLD FRONT AND ADDITIONAL LIGHT RAIN AND SHOWERS WILL DEVELOP...
POSSIBLY IN THE AFTERNOON BUT MORE LIKELY IN THE LATE
AFTERNOON/EARLY EVENING HOURS.
KACT...SCATTERED LIGHT RAIN WILL LIKLEY CONTINUE WELL INTO THE
NIGHT AHEAD OF AN APPROACHING COLD FRONT. CEILINGS WILL BE THE
MAIN CHALLENGE TONIGHT AS CIGS CURRENTLY VARY FROM LOW MVFR TO
VFR AROUND THE AIRPORT. THINK THAT CEILINGS WILL PREVAIL IN MVFR
FOR MUCH OF THE NIGHT WITH WARM AIR ADVECTION CONTINUING. COLD
FRONT WILL ARRIVE AROUND 11Z OR 5 AM WITH THE WINDS SHIFTING TO
THE NORTH. THIS WILL LIKELY CLEAR OUT THE RAIN FOR AT LEAST A FEW
HOURS. ON THURSDAY...ANOTHER UPPER LEVEL TROUGH WILL APPROACH THE
REGION BRINGING ADDITIONAL LIFT TO NORTH TEXAS. THIS ADDITIONAL
LIFT WILL COMBINE WITH WARM AIR OVERRUNNING THE SHALLOW COLD FRONT
AND ADDITIONAL LIGHT RAIN AND SHOWERS WILL DEVELOP IN THE
AFTERNOON. THERE IS A SLIGHT CHANCE THAT THE NEXT ROUND OF RAIN
MAY BEGIN IN THE LATE MORNING HOURS.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 331 PM CST WED DEC 14 2011/
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS NORTH
TEXAS THIS AFTERNOON AS A PACIFIC COLD FRONT MOVES EAST. THE UPPER
LEVEL SYSTEM RESPONSIBLE FOR DEEP LAYER ASCENT IS SHEARING OUT
ACROSS THE SOUTHERN PLAINS AND WILL MOVE NORTHEAST THIS EVENING
ALLOWING THE FRONTAL BOUNDARY TO SLOW DOWN AS IT MOVES EAST.
LATEST RUC SOUNDINGS AND LOCALLY DERIVED CONVECTIVE PARAMETERS
INDICATE THAT 700MB WARM NOSE HAS MOSTLY ERODED WITH ONLY WEAK
INHIBITION PRESENT IN VICINITY OF THE FRONT. ANYWHERE FROM
500-700J/KG OF INSTABILITY REMAINS PRESENT AND WILL SUPPORT
THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING INTO TONIGHT.
OVERALL SEVERE WEATHER THREAT IS LOW BUT SOME HAIL WILL REMAIN
POSSIBLE. FRONT WILL DRIFT SOUTH AND EAST LATER TONIGHT WITH
PRECIP TAPERING FROM WEST TO EAST.
ALTHOUGH SURFACE FRONT WILL BE SOUTH OF THE AREA ON THURSDAY AMPLE
MOISTURE WILL RIDE ATOP THE SHALLOW COOLER AIR. REMNANTS OF THE
UPPER LOW OVER THE SOUTHWEST IS EXPECTED TO EJECT NORTHEAST DURING
THE DAY TOMORROW. THIS SYSTEM SHOULD PROVIDE SUFFICIENT FORCING TO
LIFT MOISTURE IN THE 850-700MB LAYER. ELEVATED INSTABILITY WILL BE
WEAK ALTHOUGH IT SHOULD BE SUFFICIENT FOR SHOWERY TYPE PRECIP TO
DEVELOP EVEN THOUGH THE NEAR SURFACE LAYER WILL BE DRY. MODEL
GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION AND HAVE RAISED
POPS FOR THU/THU NIGHT ACROSS NORTH TEXAS.
FRIDAY AND SATURDAY STILL LOOK LIKE THE QUIETEST DAYS THROUGH THE
NEXT SEVERAL WITH MOST AREAS STAYING DRY. THE NEXT STRONG SYSTEM
IS EXPECTED TO MOVE OUT OF THE SOUTHWEST US BY SUNDAY. MOISTURE
WILL SURGE NORTHWARD AHEAD OF THIS UPPER LOW...WHICH IS FORECAST
TO REMAIN CLOSED AS IT MOVES ACROSS NORTH TEXAS. THIS SYSTEM
CONTINUES TO LOOK MORE POTENT AND AGAIN WE MAY SEE SOME
SIGNIFICANT RAINFALL AS IT MOVES THROUGH. WILL HAVE TO MONITOR FOR
SEVERE WEATHER POTENTIAL AS WE GET CLOSER TO THE EVENT.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 54 56 40 54 38 / 60 50 70 10 10
WACO, TX 58 58 42 53 42 / 90 60 70 20 20
PARIS, TX 55 57 39 51 37 / 90 40 70 20 10
DENTON, TX 51 54 38 51 33 / 40 40 70 10 10
MCKINNEY, TX 54 56 41 52 36 / 70 40 70 20 10
DALLAS, TX 55 58 41 54 41 / 70 50 70 20 10
TERRELL, TX 57 59 42 52 40 / 90 50 70 20 10
CORSICANA, TX 59 62 45 54 42 / 90 60 70 30 20
TEMPLE, TX 59 59 42 53 43 / 80 70 70 20 20
MINERAL WELLS, TX 48 52 37 50 35 / 10 40 60 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/58
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1204 PM CST TUE DEC 13 2011
.AVIATION...
FOR THE 18 UTC TAFS...AVIATION CONCERNS THIS CYCLE REVOLVE AROUND
CIGS/VISBYS THROUGH THE FIRST 18 H0URS OF THE FORECAST.
AREAS OF FOG CONTINUE TO HANG ON TOUGH ACROSS MUCH OF THE TX/OK
PANHANDLES...ESPECIALLY AT KAMA WHERE VISBYS HAVE BEEN BOUNCING
BETWEEN 1/4 TO 3/4 OF A MILE. THROUGH 00 UTC...HAVE VISBYS AT
3/4 MILE AT KAMA BUT SHOULD SEE CONDITIONS DETEIORATE TO 1/2 MILE
WITH RAIN SHOWERS AND FOG THIS EVENING. AS THE UPPER-LEVEL LOW LIFTS
TOWARD THE FOUR CORNERS REGION...UPPER-LEVEL LIFT WILL INCREASE
ACROSS THE AREA...WHICH WILL LEAD TO INCREASING RAIN CHANCES. LOW-
LEVEL MOISTURE WILL ALSO INCREASE...SO EXPET FOG TO THICKEN ONCE
AGAIN ACROSS THE PANHANDLES WITH VISBYS FALLING TO 1/2 MILE. ALONG
WITH THE FOG...HAVE INSERTED PREVAILING -RASH FOR TONIGHT BUT HAVE
OMITTED THUNDER MENTION AS CONFIDENCE IS TOO LOW THAT THUNDERSTORMS
WILL AFFECT THE TERMINALS. EXPECT SIMILAR CONDITIONS WRT FOG AND RAIN
POTENTIAL AT KDHT/KGUY TONIGHT. THE UPPER LOW WILL CONTINUE TO LIFT
ACROSS THE FOUR CORNERS REGION WEDNESDAY. A PACIFIC FRONT WILL START
TO ENTER THE NORTHERN PANHANDLES AT THE TAIL END OF THE FORECAST
PERIOD BUT EXPECT FROPA TO OCCUR AFTER 18 UTC. NONETHELESS RAIN
CHANCES SHOULD DIMINISH WED MORNING WITH CONDITIONS IMPROVING TO VFR
AT ALL THREE TERMINALS BY 16-17 UTC.
CLK
&&
.PREV DISCUSSION... /ISSUED 1034 AM CST TUE DEC 13 2011/
UPDATE...
REASON FOR UPDATE WAS TO EXPAND THE DENSE FOG ADVISORY OUT UNTIL 6 PM.
CALLS AROUND THE AREA REVEALED FOG CONTINUES TO HOLD ON ACROSS
PORTIONS OF THE SOUTHERN TEXAS PANHANDLE AND THE EASTERN TEXAS
PANHANDLE...WITH IMPROVING CONDITIONS IN THE CENTRAL TEXAS PANHANDLE.
THUS HAVE GONE EXPANDED THE DENSE FOG ADVISORY OUT UNTIL 6 PM BASED
ON THE LATEST RUC AND HRRR GUIDANCE...BUT OMITTED THE CENTRAL TEXAS
PANHANDLE DUE TO THE IMPROVED CONDITIONS. MAY HAVE TO EXPAND THE
DENSE FOG ADVISORY OUT EVEN FURTHER IN TIME BASED ON GUIDANCE AND
INCREASING LOW-LEVEL MOISTURE BUT WILL REVISIT THIS LATER IN TIME.
UPDATED PUBLIC PRODUCTS HAVE BEEN SENT.
CLK
PREV DISCUSSION... /ISSUED 716 AM CST TUE DEC 13 2011/
UPDATE...
LOWERED POPS FOR THE REMAINDER OF THE MORNING.
DISCUSSION...
BASED ON REGIONAL RADAR TRENDS AND LATEST RUC...NAM...AND HRRR
GUIDANCE...LOWERED POPS AREAWIDE FOR THIS MORNING. STILL THINKING
THE SOUTHEAST AREAS STAND TO SEE THE BEST CHANCE OF RAIN...BUT
AMOUNTS WILL BE LIGHT.
REGARDING THE DENSE FOG ADVISORY...WILL CONTINUE TO LET IT PLAY
OUT...ESPECIALLY WITH THE MORNING COMMUTE UNDERWAY. WE MADE ANOTHER
ROUND OF PHONE CALLS TO THE COUNTIES IN THE ADVISORY...AND MOST OF
THE AREAS SOUTH OF A LINE FROM FROM AMARILLO TO MIAMI TO WHEELER
CONTINUE TO SEE VERY LOW VISIBILITIES. IN FACT...THE SHERIFF/S
DEPARTMENTS IN WELLINGTON AND PANHANDLE ESTIMATED VISIBILITIES LESS
THAN 0.10 MILES. FOR THE COUNTIES IN THE ADVISORY NORTH OF THIS
LINE...THE FOG HAS GENERALLY LIFTED OR VISIBILITIES ARE BETWEEN 2 AND
5 MILES.
JACKSON
PREV DISCUSSION... /ISSUED 539 AM CST TUE DEC 13 2011/
AVIATION...
DENSE FOG AT THE DHT AND AMA TAF SITES SHOULD LAST THROUGH AT LEAST
MID MORNING BEFORE SLOWLY LIFTING INTO THE IFR RANGE FOR THE REST OF
THE DAY. VISIBILITIES WILL BE A LITTLE BETTER AT GUY...BUT THINK THE
CEILINGS THERE WILL STAY IN THE LIFR RANGE THROUGH MOST OF THE DAY.
RAIN SHOWER CHANCES WILL CONTINUE TO INCREASE THIS AFTERNOON AND
ESPECIALLY INTO THIS EVENING. A FEW THUNDERSTORMS MAY ALSO BE
POSSIBLE...BUT MOST OF THESE SHOULD REMAIN EAST OF THE TAF SITES.
CEILINGS AND VISIBILITIES ARE EXPECTED TO GO BACK DOWN AGAIN TONIGHT.
SOME MODELS EVEN WANT TO BRING DENSE FOG BACK AGAIN TO THE AMA AND
DHT TAF SITES. HAVE NOT GONE THAT LOW RIGHT NOW AS CONFIDENCE IS NOT
QUITE HIGH ENOUGH.
PREV DISCUSSION... /ISSUED 430 AM CST TUE DEC 13 2011/
DISCUSSION...
TODAY-TONIGHT: PHONE CALLS TO SHERIFF/S DEPARTMENTS AROUND THE AREA
INDICATE VISIBILITIES HAVE BEEN AT OR BELOW 1/4 MILE GENERALLY EAST
OF A LINE FROM AMARILLO TO BEAVER. ALTHOUGH SURFACE OBSERVATIONS
SHOW VISIBILITIES HAVE SLIGHTLY IMPROVED...WILL CONTINUE THE DENSE
FOG ADVISORY UNTIL 10 AM. CURRENTLY WATCHING SOME RAIN MOVE ACROSS
THE NORTHEAST PANHANDLES...AND THIS MAY BE ENOUGH TO MIX OUT THE
DENSE FOG. HOWEVER...VISIBILITIES MAY QUICKLY DETERIORATE ONCE THE
PRECIPITATION ENDS. IN FACT...SEEING THAT NOW AT AMARILLO AND EVEN
DALHART.
EXPECTING MUCH OF TODAY TO BE CLOUDY...COOL...AND SHOWERY. THINK THE
BEST CHANCE OF RAIN THIS MORNING WILL BE ACROSS THE NORTHWEST
PANHANDLES AND THE SOUTHEAST PANHANDLES. THE CENTRAL AREAS MAY
LARGELY BE VOID OF RAIN...BUT KEPT POPS IN SINCE THE AIR MASS WILL
REMAIN QUITE MOIST. RAINFALL AMOUNTS THIS MORNING ARE EXPECTED TO BE
LESS THAN 0.10" AREAWIDE.
BY THIS AFTERNOON...THE BEST CHANCE OF PRECIPITATION LOOKS TO BE
ACROSS THE EASTERN HALF OF THE PANHANDLES. DUE TO INCREASING LOW-
LEVEL MOISTURE AND STEEPENING LAPSE RATES AHEAD OF AN APPROACHING
UPPER TROUGH...FORECAST SOUNDINGS STILL INDICATE ENOUGH ELEVATED
INSTABILITY PRESENT TO WARRANT A MENTION OF THUNDERSTORMS SOUTH AND
EAST OF A LINE FROM DALHART TO GUYMON. NOT EXPECTING ANY STRONG OR SEVERE
STORMS DURING THIS TIME PERIOD. ONCE AGAIN...PRECIPITATION AMOUNTS
ARE EXPECTED TO BE LESS THAN 0.10" ACROSS THE ENTIRE AREA.
BY THIS EVENING...LARGE SCALE FORCING FOR ASCENT INCREASES
SUBSTANTIALLY. THINK SHOWERS AND THUNDERSTORMS ARE A REALLY GOOD BET
JUST ABOUT EVERYWHERE...BUT PARTICULARLY WEST OF A CLAUDE TO LIPSCOMB
LINE. AFTER MIDNIGHT...THINK THE BEST SHOWER AND THUNDERSTORM CHANCES
WILL BE EAST OF A LINE FROM GUYMON TO DALHART. NOT EXPECTING ANY
SEVERE WEATHER...BUT MAY SEE A FEW STRONG STORMS...PARTICULARLY
ACROSS THE SOUTHEAST TEXAS PANHANDLE BETWEEN 9 PM AND 3 AM. FORECAST
SOUNDINGS AND 03 UTC SREF GUIDANCE ARE SUGGESTING THE POSSIBILITY OF
MUCAPE VALUES AROUND 300 J/KG ACROSS THE SOUTHEAST TEXAS PANHANDLE.
WITH 0-6 KM SHEAR VALUES BETWEEN 70 AND 80 KT...SOME STORMS COULD
PRODUCE SMALL HAIL. SHOULD ALSO SEE SOME BENEFICIAL RAINFALL WITH
AMOUNTS POSSIBLY UP TO 0.50" OVERNIGHT.
WEDNESDAY: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE
FORECAST AREA DURING THE DAY....RESULTING IN DECREASING CHANCES FOR
PRECIPITATION. THERE STILL LOOKS TO BE JUST ENOUGH LINGERING LOW-
LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING
FOR A SLIGHT CHANCE OF SHOWERS. REMOVED THUNDERSTORMS FROM THE
FORECAST DURING THE MORNING AS ANY ELEVATED INSTABILITY SHOULD BE
EAST OF THE FORECAST AREA. THANKS TO THE DRY SLOT...FOLKS WILL BE
HAPPY TO SEE THE SUN MAKE A RETURN APPEARANCE. HIGH TEMPERATURES
SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY LOWER 60S AS STRONG
DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO
STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS.
FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW
/UP TO 775 MB/ AND WILL NOT BE ABLE TO TAP INTO THE HIGHER MOMENTUM
MID-LEVEL AIR. FORECAST SOUNDINGS ARE STILL SHOWING 30-35 KT FLOW AT
THE TOP OF THE BOUNDARY LAYER...BUT CONTINUED TO KEEP WINDS BELOW
ADVISORY CRITERIA. MET GUIDANCE CONTINUES ITS TREND OF DECREASING
THE WINDS...AND EVEN THOUGH THE MAV GUIDANCE /WHICH HAS BEEN RUNNING
TOO HIGH SINCE THIS SPRING/ STILL INDICATES LOW END ADVISORY CRITERIA
WINDS ACROSS THE SOUTHWEST TEXAS PANHANDLE...IT HAS ALSO TRENDED LOWER.
BIAS CORRECTED MAV GUIDANCE INDICATES WINDS WINDS AT OR BELOW 30 KT
ACROSS THE ENTIRE FORECAST AREA. THEREFORE...CONFIDENCE IS INCREASING
THAT A WIND ADVISORY WILL LIKELY NOT BE NEEDED. AS THE UPPER TROUGH
AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A
COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES DURING THE
EVENING WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS
THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE
PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE
UNDER 10 MPH BY MIDNIGHT THURSDAY.
THURSDAY-THURSDAY NIGHT: NO MAJOR CHANGES MADE DURING THIS TIME
PERIOD. MOSTLY SUNNY SKIES...LIGHT WINDS...SUB-SEASONAL TEMPS...AND
DRY CONDITIONS WILL PREVAIL AS HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI VALLEY BY FRIDAY.
BEYOND FRIDAY: CONFIDENCE CONTINUES TO REMAIN LOW SO VERY FEW CHANGES
WERE MADE TO THE FORECAST. THE GGEM APPEARS TO BE TOO FAR EAST WITH
THE UPPER LOW ON SATURDAY...SO IT WAS IGNORED FOR THIS FORECAST
PACKAGE. WITH THE SLOWER PROGRESSION OF THE CLOSED UPPER LOW SHOWN
BY THE ECMWF AND GFS...MOST OF THE WEEKEND MAY ACTUALLY BE DRY NOW.
SINCE THE MODELS MAY STILL HAVE SOME RUN-TO-RUN CONSISTENCY
ISSUES...DECIDED TO KEEP POPS IN THE FORECAST FROM SATURDAY NIGHT
ONWARD. IF THE SLOWER TREND CONTINUES...WE SHOULD BE ABLE TO
REMOVE POPS THROUGH AT LEAST SUNDAY MORNING. SUNDAY AFTERNOON AND
BEYOND IS WHEN THE FORECAST BEGINS TO BECOME EVEN MORE MUDDY. THE
DGEX AND GFS ARE FASTER WITH EJECTING THE UPPER LOW INTO THE CENTRAL
PLAINS MONDAY. MEANWHILE...THE ECMWF REMAINS MUCH SLOWER AND FARTHER
SOUTH WITH THE CLOSED LOW. STILL SEEING QUITE A BIT OF SPREAD IN THE
GEFS...ECMWF...AND CANADIAN ENSEMBLES. HOWEVER...STILL PREFER THE
ECMWF AS IT IS SUPPORTED BY THE ECMWF ENSEMBLE...CANADIAN
ENSEMBLE...AND JMA MODEL. BASED ON THIS...EXPECT PRECIPITATION TO
BEGIN SUNDAY NIGHT...SPREAD NORTHWARD DURING THE DAY ON MONDAY...AND
CONTINUE INTO MONDAY NIGHT. GIVEN THIS SCENARIO...ENVISION A MIX OF
RAIN AND SNOW SUNDAY NIGHT AND MONDAY MORNING ACROSS MOST OF THE
AREA. AS COLDER AIR BECOMES DEEPER BY MONDAY AFTERNOON...WOULD EXPECT
THE PRECIPITATION TYPE TO TRANSITION TO ALL SNOW. THIS SYSTEM WILL
HAVE TO BE WATCHED VERY CLOSELY AS IT HAS POTENTIAL TO BRING ANOTHER
ROUND OF WINTER WEATHER TO THE PANHANDLES.
JACKSON
FIRE WEATHER...
RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT
ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A
RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HEMPHILL...LIPSCOMB...POTTER...RANDALL...WHEELER.
OK...NONE.
&&
$$
05/03
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1034 AM CST TUE DEC 13 2011
.UPDATE...
REASON FOR UPDATE WAS TO EXPAND THE DENSE FOG ADVISORY OUT UNTIL 6 PM.
CALLS AROUND THE AREA REVEALED FOG CONTINUES TO HOLD ON ACROSS
PORTIONS OF THE SOUTHERN TEXAS PANHANDLE AND THE EASTERN TEXAS
PANHANDLE...WITH IMPROVING CONDITIONS IN THE CENTRAL TEXAS PANHANDLE.
THUS HAVE GONE EXPANDED THE DENSE FOG ADVISORY OUT UNTIL 6 PM BASED
ON THE LATEST RUC AND HRRR GUIDANCE...BUT OMITTED THE CENTRAL TEXAS
PANHANDLE DUE TO THE IMPROVED CONDITIONS. MAY HAVE TO EXPAND THE
DENSE FOG ADVISORY OUT EVEN FURTHER IN TIME BASED ON GUIDANCE AND
INCREASING LOW-LEVEL MOISTURE BUT WILL REVISIT THIS LATER IN TIME.
UPDATED PUBLIC PRODUCTS HAVE BEEN SENT.
CLK
&&
.PREV DISCUSSION... /ISSUED 716 AM CST TUE DEC 13 2011/
UPDATE...
LOWERED POPS FOR THE REMAINDER OF THE MORNING.
DISCUSSION...
BASED ON REGIONAL RADAR TRENDS AND LATEST RUC...NAM...AND HRRR
GUIDANCE...LOWERED POPS AREAWIDE FOR THIS MORNING. STILL THINKING
THE SOUTHEAST AREAS STAND TO SEE THE BEST CHANCE OF RAIN...BUT
AMOUNTS WILL BE LIGHT.
REGARDING THE DENSE FOG ADVISORY...WILL CONTINUE TO LET IT PLAY
OUT...ESPECIALLY WITH THE MORNING COMMUTE UNDERWAY. WE MADE ANOTHER
ROUND OF PHONE CALLS TO THE COUNTIES IN THE ADVISORY...AND MOST OF
THE AREAS SOUTH OF A LINE FROM FROM AMARILLO TO MIAMI TO WHEELER
CONTINUE TO SEE VERY LOW VISIBILITIES. IN FACT...THE SHERIFF/S
DEPARTMENTS IN WELLINGTON AND PANHANDLE ESTIMATED VISIBILITIES LESS
THAN 0.10 MILES. FOR THE COUNTIES IN THE ADVISORY NORTH OF THIS
LINE...THE FOG HAS GENERALLY LIFTED OR VISIBILITIES ARE BETWEEN 2 AND
5 MILES.
JACKSON
PREV DISCUSSION... /ISSUED 539 AM CST TUE DEC 13 2011/
AVIATION...
DENSE FOG AT THE DHT AND AMA TAF SITES SHOULD LAST THROUGH AT LEAST
MID MORNING BEFORE SLOWLY LIFTING INTO THE IFR RANGE FOR THE REST OF
THE DAY. VISIBILITIES WILL BE A LITTLE BETTER AT GUY...BUT THINK THE
CEILINGS THERE WILL STAY IN THE LIFR RANGE THROUGH MOST OF THE DAY.
RAIN SHOWER CHANCES WILL CONTINUE TO INCREASE THIS AFTERNOON AND
ESPECIALLY INTO THIS EVENING. A FEW THUNDERSTORMS MAY ALSO BE
POSSIBLE...BUT MOST OF THESE SHOULD REMAIN EAST OF THE TAF SITES.
CEILINGS AND VISIBILITIES ARE EXPECTED TO GO BACK DOWN AGAIN TONIGHT.
SOME MODELS EVEN WANT TO BRING DENSE FOG BACK AGAIN TO THE AMA AND
DHT TAF SITES. HAVE NOT GONE THAT LOW RIGHT NOW AS CONFIDENCE IS NOT
QUITE HIGH ENOUGH.
PREV DISCUSSION... /ISSUED 430 AM CST TUE DEC 13 2011/
DISCUSSION...
TODAY-TONIGHT: PHONE CALLS TO SHERIFF/S DEPARTMENTS AROUND THE AREA
INDICATE VISIBILITIES HAVE BEEN AT OR BELOW 1/4 MILE GENERALLY EAST
OF A LINE FROM AMARILLO TO BEAVER. ALTHOUGH SURFACE OBSERVATIONS
SHOW VISIBILITIES HAVE SLIGHTLY IMPROVED...WILL CONTINUE THE DENSE
FOG ADVISORY UNTIL 10 AM. CURRENTLY WATCHING SOME RAIN MOVE ACROSS
THE NORTHEAST PANHANDLES...AND THIS MAY BE ENOUGH TO MIX OUT THE
DENSE FOG. HOWEVER...VISIBILITIES MAY QUICKLY DETERIORATE ONCE THE
PRECIPITATION ENDS. IN FACT...SEEING THAT NOW AT AMARILLO AND EVEN
DALHART.
EXPECTING MUCH OF TODAY TO BE CLOUDY...COOL...AND SHOWERY. THINK THE
BEST CHANCE OF RAIN THIS MORNING WILL BE ACROSS THE NORTHWEST
PANHANDLES AND THE SOUTHEAST PANHANDLES. THE CENTRAL AREAS MAY
LARGELY BE VOID OF RAIN...BUT KEPT POPS IN SINCE THE AIR MASS WILL
REMAIN QUITE MOIST. RAINFALL AMOUNTS THIS MORNING ARE EXPECTED TO BE
LESS THAN 0.10" AREAWIDE.
BY THIS AFTERNOON...THE BEST CHANCE OF PRECIPITATION LOOKS TO BE
ACROSS THE EASTERN HALF OF THE PANHANDLES. DUE TO INCREASING LOW-
LEVEL MOISTURE AND STEEPENING LAPSE RATES AHEAD OF AN APPROACHING
UPPER TROUGH...FORECAST SOUNDINGS STILL INDICATE ENOUGH ELEVATED
INSTABILITY PRESENT TO WARRANT A MENTION OF THUNDERSTORMS SOUTH AND
EAST OF A LINE FROM DALHART TO GUYMON. NOT EXPECTING ANY STRONG OR SEVERE
STORMS DURING THIS TIME PERIOD. ONCE AGAIN...PRECIPITATION AMOUNTS
ARE EXPECTED TO BE LESS THAN 0.10" ACROSS THE ENTIRE AREA.
BY THIS EVENING...LARGE SCALE FORCING FOR ASCENT INCREASES
SUBSTANTIALLY. THINK SHOWERS AND THUNDERSTORMS ARE A REALLY GOOD BET
JUST ABOUT EVERYWHERE...BUT PARTICULARLY WEST OF A CLAUDE TO LIPSCOMB
LINE. AFTER MIDNIGHT...THINK THE BEST SHOWER AND THUNDERSTORM CHANCES
WILL BE EAST OF A LINE FROM GUYMON TO DALHART. NOT EXPECTING ANY
SEVERE WEATHER...BUT MAY SEE A FEW STRONG STORMS...PARTICULARLY
ACROSS THE SOUTHEAST TEXAS PANHANDLE BETWEEN 9 PM AND 3 AM. FORECAST
SOUNDINGS AND 03 UTC SREF GUIDANCE ARE SUGGESTING THE POSSIBILITY OF
MUCAPE VALUES AROUND 300 J/KG ACROSS THE SOUTHEAST TEXAS PANHANDLE.
WITH 0-6 KM SHEAR VALUES BETWEEN 70 AND 80 KT...SOME STORMS COULD
PRODUCE SMALL HAIL. SHOULD ALSO SEE SOME BENEFICIAL RAINFALL WITH
AMOUNTS POSSIBLY UP TO 0.50" OVERNIGHT.
WEDNESDAY: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE
FORECAST AREA DURING THE DAY....RESULTING IN DECREASING CHANCES FOR
PRECIPITATION. THERE STILL LOOKS TO BE JUST ENOUGH LINGERING LOW-
LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING
FOR A SLIGHT CHANCE OF SHOWERS. REMOVED THUNDERSTORMS FROM THE
FORECAST DURING THE MORNING AS ANY ELEVATED INSTABILITY SHOULD BE
EAST OF THE FORECAST AREA. THANKS TO THE DRY SLOT...FOLKS WILL BE
HAPPY TO SEE THE SUN MAKE A RETURN APPEARANCE. HIGH TEMPERATURES
SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY LOWER 60S AS STRONG
DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO
STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS.
FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW
/UP TO 775 MB/ AND WILL NOT BE ABLE TO TAP INTO THE HIGHER MOMENTUM
MID-LEVEL AIR. FORECAST SOUNDINGS ARE STILL SHOWING 30-35 KT FLOW AT
THE TOP OF THE BOUNDARY LAYER...BUT CONTINUED TO KEEP WINDS BELOW
ADVISORY CRITERIA. MET GUIDANCE CONTINUES ITS TREND OF DECREASING
THE WINDS...AND EVEN THOUGH THE MAV GUIDANCE /WHICH HAS BEEN RUNNING
TOO HIGH SINCE THIS SPRING/ STILL INDICATES LOW END ADVISORY CRITERIA
WINDS ACROSS THE SOUTHWEST TEXAS PANHANDLE...IT HAS ALSO TRENDED LOWER.
BIAS CORRECTED MAV GUIDANCE INDICATES WINDS WINDS AT OR BELOW 30 KT
ACROSS THE ENTIRE FORECAST AREA. THEREFORE...CONFIDENCE IS INCREASING
THAT A WIND ADVISORY WILL LIKELY NOT BE NEEDED. AS THE UPPER TROUGH
AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A
COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES DURING THE
EVENING WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS
THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE
PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE
UNDER 10 MPH BY MIDNIGHT THURSDAY.
THURSDAY-THURSDAY NIGHT: NO MAJOR CHANGES MADE DURING THIS TIME
PERIOD. MOSTLY SUNNY SKIES...LIGHT WINDS...SUB-SEASONAL TEMPS...AND
DRY CONDITIONS WILL PREVAIL AS HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI VALLEY BY FRIDAY.
BEYOND FRIDAY: CONFIDENCE CONTINUES TO REMAIN LOW SO VERY FEW CHANGES
WERE MADE TO THE FORECAST. THE GGEM APPEARS TO BE TOO FAR EAST WITH
THE UPPER LOW ON SATURDAY...SO IT WAS IGNORED FOR THIS FORECAST
PACKAGE. WITH THE SLOWER PROGRESSION OF THE CLOSED UPPER LOW SHOWN
BY THE ECMWF AND GFS...MOST OF THE WEEKEND MAY ACTUALLY BE DRY NOW.
SINCE THE MODELS MAY STILL HAVE SOME RUN-TO-RUN CONSISTENCY
ISSUES...DECIDED TO KEEP POPS IN THE FORECAST FROM SATURDAY NIGHT
ONWARD. IF THE SLOWER TREND CONTINUES...WE SHOULD BE ABLE TO
REMOVE POPS THROUGH AT LEAST SUNDAY MORNING. SUNDAY AFTERNOON AND
BEYOND IS WHEN THE FORECAST BEGINS TO BECOME EVEN MORE MUDDY. THE
DGEX AND GFS ARE FASTER WITH EJECTING THE UPPER LOW INTO THE CENTRAL
PLAINS MONDAY. MEANWHILE...THE ECMWF REMAINS MUCH SLOWER AND FARTHER
SOUTH WITH THE CLOSED LOW. STILL SEEING QUITE A BIT OF SPREAD IN THE
GEFS...ECMWF...AND CANADIAN ENSEMBLES. HOWEVER...STILL PREFER THE
ECMWF AS IT IS SUPPORTED BY THE ECMWF ENSEMBLE...CANADIAN
ENSEMBLE...AND JMA MODEL. BASED ON THIS...EXPECT PRECIPITATION TO
BEGIN SUNDAY NIGHT...SPREAD NORTHWARD DURING THE DAY ON MONDAY...AND
CONTINUE INTO MONDAY NIGHT. GIVEN THIS SCENARIO...ENVISION A MIX OF
RAIN AND SNOW SUNDAY NIGHT AND MONDAY MORNING ACROSS MOST OF THE
AREA. AS COLDER AIR BECOMES DEEPER BY MONDAY AFTERNOON...WOULD EXPECT
THE PRECIPITATION TYPE TO TRANSITION TO ALL SNOW. THIS SYSTEM WILL
HAVE TO BE WATCHED VERY CLOSELY AS IT HAS POTENTIAL TO BRING ANOTHER
ROUND OF WINTER WEATHER TO THE PANHANDLES.
JACKSON
FIRE WEATHER...
RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT
ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A
RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HEMPHILL...LIPSCOMB...POTTER...RANDALL...WHEELER.
OK...NONE.
&&
$$
05/03
AREA FORECAST DISCUSSION
NWS SPOKANE WA
951 AM PST Tue Dec 13 2011
.SYNOPSIS...High pressure will be over the Inland Northwest for
through Wednesday. A weak wave will track through British Columbia
and may bring some light mountain snow showers today. A stronger and
more organized Pacific storm system will arrive Wednesday evening
and Thursday with the possibility of a chance of snow
accumulations down to the valley floors.
&&
.DISCUSSION...
Made minor changes to the forecast this morning. Stratus is
widespread across the low lands with tops to close to 5k ft.
Meanwhile moisture above 500mb has generated high clouds that are
moving into the region ahead of the advancing shortwave trough.
Weak lift associated with the advancing wave and helped deepen the
boundary layer, raising ceilings and generated light flurries and
spotty freezing drizzle. Anticipate the light precipitation threat
to wane through the afternoon as cloud decks continue to rise. The
HRR, NAM and RUC increase SE winds across the Palouse that may
help scour out the stratus and press it into the Columbia Basin.
Otherwise anticipate low clouds for much of the day and night.
/rfox.
&&
.AVIATION...
18Z TAFs...Stratus is widespread with IFR/MVFR CIGS on a slow and
gradual improving trend. Most TAF sites have VSBYS improved to
above 6 miles. The problem area will continue to be KGEG where the
IFR CIGS/VSBYS will continue through much of the day with only
slight improvements in VSBYS in the afternoon. Anticipate the MVFR
deck to lift from KLWS and KPUW late this afternoon and early
evening, but return temporarily overnight. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 21 31 25 33 21 / 10 10 0 60 60 10
Coeur d`Alene 32 22 33 26 33 24 / 10 10 10 70 60 10
Pullman 29 23 35 27 35 24 / 10 10 10 50 60 20
Lewiston 33 25 37 29 40 25 / 0 10 10 30 50 10
Colville 31 20 32 22 34 21 / 10 10 10 70 60 10
Sandpoint 31 22 32 24 33 23 / 10 10 10 70 70 10
Kellogg 31 22 32 25 31 24 / 10 10 10 60 70 20
Moses Lake 28 16 32 21 36 15 / 0 0 10 40 20 10
Wenatchee 29 23 32 26 36 24 / 0 0 10 60 20 10
Omak 31 18 32 21 36 18 / 10 0 10 70 30 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Air Stagnation Advisory until Noon PST Thursday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
Lewiston Area-Northern Panhandle.
WA...Air Stagnation Advisory until Noon PST Thursday for East Slopes
Northern Cascades-Lower Garfield and Asotin Counties-Moses
Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan
Valley-Spokane Area-Upper Columbia Basin-Washington Palouse-
Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
928 PM CST WED DEC 14 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY
751 PM CST WED DEC 14 2011
01Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TORUGH OVER MINNESOTA WITH A SHORTWAVE EVIDENT CROSSING SOUTHEAST
MINNESOTA. DPVA AHEAD OF THIS SHORTWAVE HELPING TO PRODUCE SHOWERS
MOSTLY ALONG AND NORTH OF I-90. ELSEWHERE...AREAS OF DRIZZLE
EXISTS DUE TO A PERSISTENT WEAK WARM ADVECTION AHEAD OF LOW
PRESSURE LIFTING NORTHEAST...LOCATED NEAR WATERLOO IOWA AS OF 01Z.
REGARDING THE FOG...DENSE FOG THAT DEVELOPED DURING THE AFTERNOON
DOES SEEM TO BE DISSIPATING...DUE TO EITHER RAIN MOVING ACROSS OR
WINDS TURNING NORTHWEST IN THE WAKE OF THE LOW.
SHOWERS SHOULD CONTINUE TO LIFT TO THE NORTHEAST DURING THE REST
OF THE EVENING...WITH DRIZZLE SLOWLY ENDING THROUGH THE NIGHT AS
THE LOW PULLS AWAY AND LIFT DIMINISHES. HAVE REDUCED PRECIPITATION
CHANCES FOR PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN
THIS EVENING...DUE TO MAINLY AREAS OF DRIZZLE THAT ARE NOT
PRODUCING A WIDESPREAD 0.01 OF AN INCH OF RAINFALL. ALSO...
DECREASED PRECIPITATION CHANCES AFTER MIDNIGHT WITH THE
DIMINISHING LIFT. STILL MAINTAINED SOME CHANCE...THOUGH...GIVEN
HRRR RUNS PERSISTENT SHOWING OF SOME DRIZZLE COMING IN AFTER
MIDNIGHT. THINKING IS THE HRRR MIGHT BE USING TURBULENCE BETWEEN
THE MOIST LOW LEVELS AND DRYING COMING IN ALOFT SEEN ON WATER
VAPOR AND ON THE 00Z OAX/ABR SOUNDINGS. AS FAR AS THE FOG
SITUATION GOES...WITH RECENT TRENDS OF VISIBILITIES CLIMBING...
MIGHT BE ABLE TO START CANCELLING SOME OF THE DENSE FOG ADVISORIES
EARLY. CERTAINLY MORE CONFIDENT OF THE DENSE FOG DISSIPATING ONCE
WINDS TURN WESTERLY...AS NOTED BY VISIBILITIES AT OR ABOVE 1 MILE
ALONG/WEST OF I-35 IN SOUTHERN MINNESOTA/NORTHERN IOWA.
REGARDING PRECIPITATION TYPE TONIGHT...DID REMOVE ANY MENTION OF
SNOW SINCE MODEL SOUNDINGS AS WELL AS RAOBS SUGGEST NO ICE
PRODUCTION. ALSO...LIMITED SOME OF THE FREEZING DRIZZLE
DEVELOPMENT...SHOULD IT OCCUR AT ALL...TO LATE IN THE NIGHT AS IT
MAY TAKE AWHILE FOR TEMPERATURES TO FALL GIVEN THE WIDESPREAD
ABOVE FREEZING TEMPERATURES OFF TO THE NORTHWEST.
FOR THURSDAY AND THURSDAY NIGHT...CONCERN IS GROWING THAT WE MAY
BE DEALING WITH MORE STRATUS THAN IS CURRENTLY IN THE FORECAST.
CURRENT SATELLITE IMAGERY SHOWERS STRATUS COVERING ALL OF NORTH
DAKOTA INTO NORTHEAST SOUTH DAKOTA AND EASTWARD INTO OUR FORECAST
AREA. THE 18Z NAM/GFS POORLY FORECAST THE 00Z BIS SOUNDING...WITH
900MB TEMPERATURES 4C TOO WARM...SO THE MODELS MAY NOT BE HANDLING
THE STRATUS WELL. THINKING THAT THE STRATUS MAY END UP LINGERING
RIGHT THROUGH THURSDAY NIGHT...WAITING FOR THE SURFACE RIDGE AXIS
TO PASS ON FRIDAY BEFORE IT CAN CLEAR. THIS WOULD MAKE SENSE GIVEN
HOW MUCH MOISTURE WE HAVE RECEIVED...TRYING TO PUSH COLDER AIR
INTO THE MORE MOIST AIRMASS...AND SUBSIDENCE ALOFT TRAPPING THE
LOW LEVEL MOISTURE. WITH MORE CLOUDS...TEMPERATURES THURSDAY
NIGHT COULD END UP TOO COLD. WILL PASS ON THE STRATUS ISSUE FOR THE
NEXT FULL FORECAST. FOR NOW...HAVE ONLY INCREASED CLOUD COVER SOME
ON THURSDAY INTO THURSDAY EVENING.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
305 PM CST WED DEC 14 2011
YET ANOTHER SHORT WAVE TROUGH ZIPS THROUGH THE REGION IN NORTHWEST
FLOW ON SATURDAY. ONCE AGAIN...THERE IS A CHANCE FOR A BRIEF PERIOD
OF LIGHT SNOW ALONG THE BAROCLINIC ZONE RUNNING FROM NORTHWEST
THROUGH SOUTHEAST ACROSS THE REGION.
BEYOND THIS...THE ATTENTION TURNS TO A POTENT STORM SYSTEM WHICH
WILL TAKE SHAPE OVER THE DESERT SOUTHWEST OVER THE WEEKEND...AND
WILL MOVE INTO OUR AREA BY MONDAY. THE COMPUTER MODEL SIMULATIONS
CONTINUE TO STRUGGLE AND ARE AT ODDS WITH EACH OTHER AS TO HOW THIS
WILL EVOLVE. ONE SET OF SOLUTIONS SHOW A SLOW-MOVING SOUTHERN STREAM
CLOSED SYSTEM...KEEPING THE BULK OF ANY PRECIPITATION SOUTH OF OUR
AREA. BUT OTHER SOLUTIONS SUGGEST SOME PHASING WITH THE NORTHERN
STREAM...WITH A FASTER MOVEMENT AND STRONGER SYSTEM MOVING RIGHT
THROUGH THE HEART OF THE NATION. WHILE CONFIDENCE REMAINS SOMEWHAT
LOW ON WHAT WILL EVENTUALLY HAPPEN...THERE IS ENOUGH OF A HINT IN THE
VARIOUS SOLUTIONS THAT POINT TO THE LATTER OPTION. POPS ARE STILL
SOMEWHAT LOW...BUT WE SHOULD BEGIN TO HAVE A BETTER IDEA ON THIS
SYSTEM IN THE COMING DAYS.
&&
.AVIATION...TONIGHT AND THURSDAY
600 PM CST WED DEC 14 2011
MOIST SOUTHERLY FLOW ASSOCIATED WITH LOW PRESSURE OVER IOWA
CONTINUES IFR AND LIFR CONDITIONS ACROSS NORTHEAST IOWA...AND
MUCH OF WISCONSIN. WITH AMPLE MOISTURE AND LIGHT WINDS...DENSE FOG
HAS DEVELOPED ACROSS MUCH OF THE AREA. A SMALL AREA OF MVFR/VFR
CONDITIONS WAS ACROSS NORTH CENTRAL IOWA AND SOUTHEAST
MINNESOTA...THOUGH EXPECTING THIS TO ERODE/FILL IN WITH LIFR/IFR
CONDITIONS THROUGH EARLY THIS EVENING.
CHALLENGES AT KRST AND KLSE ARE CEILINGS AND VISIBILITIES UNTIL
INCREASING NORTHWEST WINDS CAN BEGIN SCOURING OUT SOME OF THE NEAR
SURFACE MOISTURE. WITH PRECIPITATION ENDING LATE THIS
EVENING...VISIBILITIES SHOULD IMPROVE TO MVFR AT BOTH KRST AND
KLSE. CEILINGS WILL REMAIN AROUND IFR/LIFR AT KRST THROUGH 13Z
THURSDAY...AND THEN SLOWLY IMPROVE TO MVFR BY MID DAY. AT
KLSE...CURRENT IFR CEILINGS MAY DROP OCCASIONALLY TO LIFR THROUGH
06Z...THEN BEGIN TO IMPROVE TO MVFR BY MID AFTERNOON.
NORTHWEST WINDS WILL INCREASE BEHIND DEPARTING LOW THURSDAY
MORNING WITH GUSTS UP TO 30 KTS AT KRST...AND 25 KT AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
928 PM CST WED DEC 14 2011
WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ079-088-096.
IA...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ011-030.
&&
$$
SHORT TERM...AJ
LONG TERM....MW
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
854 PM CST WED DEC 14 2011
.UPDATE...
DENSE FOG NOT WIDESPREAD IN THE ADVISORY AREA...BUT SOME
VISIBILITIES ARE DROPPING AGAIN TO 1/4 MILE. WILL KEEP ADVISORY
FOR NOW AS BAGGY PRESSURE GRADIENT OF SURFACE LOW MOVES ACROSS
LATE THIS EVENING. WITH THE COLD AIR ADVECTION ON THE BACK
SIDE...VISIBILITIES WILL THEN IMPROVE.
&&
.AVIATION/06Z TAFS/...
IFR CIGS TO CONTINUE TONIGHT WITH SOME LIFR CIGS/VSBYS ESPECIALLY
OVER SOUTH CENTRAL WISCONSIN WITH THE BAGGY PRESSURE GRADIENT OF
THE SURFACE LOW. ONCE THE LOW MOVES NORTHEAST THE COLD AIR
ADVECTION WILL IMPROVE VSBYS BUT IFR CIGS TO CONTINUE UNTIL LATE
THURSDAY MORNING...WITH MAINLY MVFR CIGS BY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 508 PM CST WED DEC 14 2011/
UPDATE...
WILL EXPAND DENSE FOG ADVISORY FOR DODGE AND FOND DU LAC COUNTIES.
HENTZ
PREV DISCUSSION... /ISSUED 316 PM CST WED DEC 14 2011/
TONIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SHEARED VORT MAX STRETCHING FROM NORTHEAST NEW MEXICO TO EASTERN
NEBRASKA APPARENT IN 1945Z WATER VAPOR IMAGERY AND RUC ANALYSIS.
RAIN SPREAD BACK INTO SOUTHERN WI EARLY THIS AFTERNOON...SUPPORTED
BY 500MB VORT MAX PUSHING INTO SOUTH CENTRAL WI...WARM AIR ADVECTION
AND CONTINUED ISENTROPIC LIFT. OMEGA VALUES WILL ALSO INCREASE
BETWEEN NOW AND 7 PM AS WELL...PER RUC AND NAM MODEL SNDGS.
REGIONAL RADAR NOW ROUGHLY SHOWING DRY SLOT MOVING INTO CENTRAL
IOWA...CORRESPONDING TO THE CENTER OF SFC LOW PRESSURE. OBS STILL
SHOWING DRIZZLE IN THE VICINITY. SFC LOW WILL MOVE INTO NORTHEAST
IOWA AROUND 00Z...AND CLIP THE NORTHWEST FORECAST AREA AS IT MOVES
ACROSS CENTRAL WI AT 03Z. THE SFC TROUGH/COLD FRONT WILL THEN TREK
ACROSS SOUTHEAST WI FROM 05Z TO 09Z...USHERING IN COLDER AND DRIER
AIR...AS THE SFC LOW MOVES INTO EASTERN UPPER MICHIGAN. LOW LEVELS
WILL REMAIN MOIST BEHIND THE FRONT...BUT DRY OUT ALOFT...THUS
CAUSING DRIZZLE BEHIND THE DEPARTING LOW THROUGH AROUND 15Z/9AM THU
MORNING.
THE BAGGY PRESSURE GRADIENT OVER THE WESTERN FORECAST AREA WILL
ALLOW FOR AREAS OF DENSE FOG THROUGH LATE EVENING UNTIL THE COLD
FRONT COMES THROUGH AND THE WINDS INCREASE. DENSE FOG ADVY POSTED.
TEMPERATURES WILL KEEP RISING THROUGH THE EVENING...REACHING OUR
DAILY HIGH IN THE UPPER 40S/LOWER 50S AROUND MIDNIGHT. TEMPS WILL
GRADUALLY FALL THROUGH THE DAY THU...DROPPING DOWN TO AROUND
FREEZING FROM NW TO SE DURING THE AFTERNOON HOURS.
PRECIP IS EXPECTED TO END BY LATE THU MORNING...AND CLOUDS SHOULD
BREAK UP DURING THE AFTERNOON HOURS...BECOMING PARTLY CLOUDY BY
EVENING.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE IS HIGH.
SKIES CONTINUE TO CLEAR OUT EARLY THURSDAY EVENING AS THE LOW
PULLS AWAY AND HIGH PRESSURE BUILDS IN. THINGS COOL DOWN...BUT
REMAIN AT OR SLIGHTLY ABOVE NORMAL.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS MEDIUM.
A COUPLE OF WEAK MID LEVEL SHORT WAVES COME THROUGH THE FAST
NORTHWEST FLOW FRIDAY NIGHT AND AGAIN SATURDAY AFTERNOON. MOISTURE
BEGINS TO RETURN AND THERE IS SOME INDICATION WE COULD GET ENOUGH
COLUMN SATURATION TO SQUEEZE OUT A FEW FLAKES OF SNOW. HAVE
INTRODUCED A SLIGHT CHANCE OF LIGHT SNOW...BUT LITTLE OR NO
ACCUMULATION IS EXPECTED. THE GFS AND THE NAM ARE HINTING AT SOME
VERY LIGHT QPF THROUGH THIS PERIOD.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
QUIET CONDITIONS EXPECTED THIS PERIOD AS WEAK RIDGING MOVES
THROUGH. TEMPS REMAIN AT OR ABOVE NORMAL.
SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE IS LOW.
THERE IS MAJOR MODEL UNCERTAINTY FOR EARLY NEXT WEEK. AT ISSUE IS
WHETHER WE/LL SEE A LOW MOVE UP INTO THE GREAT LAKES AND GIVE US
RAIN...OR STAY WELL TO THE SOUTH AND KEEP US DRY...OR TAKE A
COMPROMISE OF THE TWO AND POSSIBLY GIVE US SOME ACCUMULATING SNOW.
THE GFS HAS MAINTAINED IT/S SOUTHERN DRY SOLUTION FOR US...THE
CANADIAN LOOKS FAIRLY WARM/RAINY WITH A LOW MOVING INTO THE
CENTRAL GREAT LAKES...WHILE THE ECMWF IS A COMPROMISER TAKING A
LOW THROUGH CENTRAL ILLINOIS/INDIANA. THE ECMWF WOULD BE COOLER
DURING THE PRECIP AND THIS COULD RESULT IN SOME ACCUMULATING
SNOW...NOTHING MAJOR AT THIS POINT. THE MODELS ARE HAVING A VERY
DIFFICULT TIME PHASING ENERGY FROM THE SOUTHERN AND NORTHERN
STREAMS. HAVE KEPT POPS IN THE CHC CATEGORY UNTIL WE GET A LITTLE
MORE CONSENSUS.
AVIATION/00Z TAFS/...SURFACE LOW PRESSURE WILL TRACK ACROSS
NORTHEAST IOWA...CENTRAL WI AND EASTERN UPPER MICHIGAN THROUGH
TONIGHT. BAGGY PRESSURE GRADIENT BENEATH THE SFC LOW WILL COVER
SOUTH CENTRAL WI...ALLOWING AREAS OF DENSE FOG TO DEVELOP/PERSIST
THROUGH THE EVENING.
RAIN ASSOCIATED WITH THE 500MB SHORTWAVE...850MB WARM AIR
ADVECTION...AND STRONG OMEGA WILL DIMINISH AS THE SFC LOW COMES
OVERHEAD...AS THE DRY SLOT HITS THE REGION.
COLD FRONTAL PASSAGE WILL OCCUR BETWEEN 05Z AND 08Z TONIGHT. STRONG
COLD ADVECTION THU AM WILL IMPROVE CONDITIONS BY RAISING THE
CEILINGS AND IMPROVING VISIBILITY. WIND GUSTS TO 30 KNOTS
POSSIBLE...ESPECIALLY AT MKE. CLOUDS SHOULD SCATTER OUT DURING THU
AFTERNOON.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 6 PM TNT THROUGH
9 PM THU EVENING. BREEZY SSWLY WINDS AND HIGH WAVES WILL DEVELOP
THIS EVENING WITH A COLD FRONTAL PASSAGE EXPECTED TO SHIFT THE WINDS
TO THE WEST BY 09Z TNT. STRONG COLD ADVECTION WILL COMBINE WITH THE
RELATIVELY MILD LAKE MI WATER TEMPS TO PRODUCE UNSTABLE CONDITIONS
IN THE LOW LEVEL ATMOSPHERE. THIS WILL ENHANCE THE ALREADY MODERATE
WIND FIELD WITH WIND GUSTS EXPECTED TO REACH 30 KTS. THE WAVES WILL
DECREASE AFTER COLD FROPA DUE TO THE WLY COMPONENT OF THE WIND AND
THEREFORE LESS FETCH TO GENERATE WAVES. HOWEVER...HIGH WAVES WILL
STILL OCCUR OVER THE OPEN WATERS OF LAKE MI. THE WINDS WILL SUBSIDE
BY LATE THU EVENING AS A LARGE HIGH PRESSURE AREA APPROACHES FROM
THE WEST.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR WIZ046-047-056-
057-062-063-067-068.
DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ051-058.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THURSDAY FOR LMZ643>646.
&&
$$
UPDATE...HENTZ
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
751 PM CST WED DEC 14 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY
751 PM CST WED DEC 14 2011
01Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TORUGH OVER MINNESOTA WITH A SHORTWAVE EVIDENT CROSSING SOUTHEAST
MINNESOTA. DPVA AHEAD OF THIS SHORTWAVE HELPING TO PRODUCE SHOWERS
MOSTLY ALONG AND NORTH OF I-90. ELSEWHERE...AREAS OF DRIZZLE
EXISTS DUE TO A PERSISTENT WEAK WARM ADVECTION AHEAD OF LOW
PRESSURE LIFTING NORTHEAST...LOCATED NEAR WATERLOO IOWA AS OF 01Z.
REGARDING THE FOG...DENSE FOG THAT DEVELOPED DURING THE AFTERNOON
DOES SEEM TO BE DISSIPATING...DUE TO EITHER RAIN MOVING ACROSS OR
WINDS TURNING NORTHWEST IN THE WAKE OF THE LOW.
SHOWERS SHOULD CONTINUE TO LIFT TO THE NORTHEAST DURING THE REST
OF THE EVENING...WITH DRIZZLE SLOWLY ENDING THROUGH THE NIGHT AS
THE LOW PULLS AWAY AND LIFT DIMINISHES. HAVE REDUCED PRECIPITATION
CHANCES FOR PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN
THIS EVENING...DUE TO MAINLY AREAS OF DRIZZLE THAT ARE NOT
PRODUCING A WIDESPREAD 0.01 OF AN INCH OF RAINFALL. ALSO...
DECREASED PRECIPITATION CHANCES AFTER MIDNIGHT WITH THE
DIMINISHING LIFT. STILL MAINTAINED SOME CHANCE...THOUGH...GIVEN
HRRR RUNS PERSISTENT SHOWING OF SOME DRIZZLE COMING IN AFTER
MIDNIGHT. THINKING IS THE HRRR MIGHT BE USING TURBULENCE BETWEEN
THE MOIST LOW LEVELS AND DRYING COMING IN ALOFT SEEN ON WATER
VAPOR AND ON THE 00Z OAX/ABR SOUNDINGS. AS FAR AS THE FOG
SITUATION GOES...WITH RECENT TRENDS OF VISIBILITIES CLIMBING...
MIGHT BE ABLE TO START CANCELLING SOME OF THE DENSE FOG ADVISORIES
EARLY. CERTAINLY MORE CONFIDENT OF THE DENSE FOG DISSIPATING ONCE
WINDS TURN WESTERLY...AS NOTED BY VISIBILITIES AT OR ABOVE 1 MILE
ALONG/WEST OF I-35 IN SOUTHERN MINNESOTA/NORTHERN IOWA.
REGARDING PRECIPITATION TYPE TONIGHT...DID REMOVE ANY MENTION OF
SNOW SINCE MODEL SOUNDINGS AS WELL AS RAOBS SUGGEST NO ICE
PRODUCTION. ALSO...LIMITED SOME OF THE FREEZING DRIZZLE
DEVELOPMENT...SHOULD IT OCCUR AT ALL...TO LATE IN THE NIGHT AS IT
MAY TAKE AWHILE FOR TEMPERATURES TO FALL GIVEN THE WIDESPREAD
ABOVE FREEZING TEMPERATURES OFF TO THE NORTHWEST.
FOR THURSDAY AND THURSDAY NIGHT...CONCERN IS GROWING THAT WE MAY
BE DEALING WITH MORE STRATUS THAN IS CURRENTLY IN THE FORECAST.
CURRENT SATELLITE IMAGERY SHOWERS STRATUS COVERING ALL OF NORTH
DAKOTA INTO NORTHEAST SOUTH DAKOTA AND EASTWARD INTO OUR FORECAST
AREA. THE 18Z NAM/GFS POORLY FORECAST THE 00Z BIS SOUNDING...WITH
900MB TEMPERATURES 4C TOO WARM...SO THE MODELS MAY NOT BE HANDLING
THE STRATUS WELL. THINKING THAT THE STRATUS MAY END UP LINGERING
RIGHT THROUGH THURSDAY NIGHT...WAITING FOR THE SURFACE RIDGE AXIS
TO PASS ON FRIDAY BEFORE IT CAN CLEAR. THIS WOULD MAKE SENSE GIVEN
HOW MUCH MOISTURE WE HAVE RECEIVED...TRYING TO PUSH COLDER AIR
INTO THE MORE MOIST AIRMASS...AND SUBSIDENCE ALOFT TRAPPING THE
LOW LEVEL MOISTURE. WITH MORE CLOUDS...TEMPERATURES THURSDAY
NIGHT COULD END UP TOO COLD. WILL PASS ON THE STRATUS ISSUE FOR THE
NEXT FULL FORECAST. FOR NOW...HAVE ONLY INCREASED CLOUD COVER SOME
ON THURSDAY INTO THURSDAY EVENING.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
305 PM CST WED DEC 14 2011
YET ANOTHER SHORT WAVE TROUGH ZIPS THROUGH THE REGION IN NORTHWEST
FLOW ON SATURDAY. ONCE AGAIN...THERE IS A CHANCE FOR A BRIEF PERIOD
OF LIGHT SNOW ALONG THE BAROCLINIC ZONE RUNNING FROM NORTHWEST
THROUGH SOUTHEAST ACROSS THE REGION.
BEYOND THIS...THE ATTENTION TURNS TO A POTENT STORM SYSTEM WHICH
WILL TAKE SHAPE OVER THE DESERT SOUTHWEST OVER THE WEEKEND...AND
WILL MOVE INTO OUR AREA BY MONDAY. THE COMPUTER MODEL SIMULATIONS
CONTINUE TO STRUGGLE AND ARE AT ODDS WITH EACH OTHER AS TO HOW THIS
WILL EVOLVE. ONE SET OF SOLUTIONS SHOW A SLOW-MOVING SOUTHERN STREAM
CLOSED SYSTEM...KEEPING THE BULK OF ANY PRECIPITATION SOUTH OF OUR
AREA. BUT OTHER SOLUTIONS SUGGEST SOME PHASING WITH THE NORTHERN
STREAM...WITH A FASTER MOVEMENT AND STRONGER SYSTEM MOVING RIGHT
THROUGH THE HEART OF THE NATION. WHILE CONFIDENCE REMAINS SOMEWHAT
LOW ON WHAT WILL EVENTUALLY HAPPEN...THERE IS ENOUGH OF A HINT IN THE
VARIOUS SOLUTIONS THAT POINT TO THE LATTER OPTION. POPS ARE STILL
SOMEWHAT LOW...BUT WE SHOULD BEGIN TO HAVE A BETTER IDEA ON THIS
SYSTEM IN THE COMING DAYS.
&&
.AVIATION...TONIGHT AND THURSDAY
600 PM CST WED DEC 14 2011
MOIST SOUTHERLY FLOW ASSOCIATED WITH LOW PRESSURE OVER IOWA
CONTINUES IFR AND LIFR CONDITIONS ACROSS NORTHEAST IOWA...AND
MUCH OF WISCONSIN. WITH AMPLE MOISTURE AND LIGHT WINDS...DENSE FOG
HAS DEVELOPED ACROSS MUCH OF THE AREA. A SMALL AREA OF MVFR/VFR
CONDITIONS WAS ACROSS NORTH CENTRAL IOWA AND SOUTHEAST
MINNESOTA...THOUGH EXPECTING THIS TO ERODE/FILL IN WITH LIFR/IFR
CONDITIONS THROUGH EARLY THIS EVENING.
CHALLENGES AT KRST AND KLSE ARE CEILINGS AND VISIBILITIES UNTIL
INCREASING NORTHWEST WINDS CAN BEGIN SCOURING OUT SOME OF THE NEAR
SURFACE MOISTURE. WITH PRECIPITATION ENDING LATE THIS
EVENING...VISIBILITIES SHOULD IMPROVE TO MVFR AT BOTH KRST AND
KLSE. CEILINGS WILL REMAIN AROUND IFR/LIFR AT KRST THROUGH 13Z
THURSDAY...AND THEN SLOWLY IMPROVE TO MVFR BY MID DAY. AT
KLSE...CURRENT IFR CEILINGS MAY DROP OCCASIONALLY TO LIFR THROUGH
06Z...THEN BEGIN TO IMPROVE TO MVFR BY MID AFTERNOON.
NORTHWEST WINDS WILL INCREASE BEHIND DEPARTING LOW THURSDAY
MORNING WITH GUSTS UP TO 30 KTS AT KRST...AND 25 KT AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 PM CST WED DEC 14 2011
MN...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
MNZ079-086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
IAZ008>011-018-019-029-030.
WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR
WIZ017-029-032>034-041>044-053>055-061.
&&
$$
SHORT TERM...AJ
LONG TERM....MW
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
508 PM CST WED DEC 14 2011
.UPDATE...
WILL EXPAND DENSE FOG ADVISORY FOR DODGE AND FOND DU LAC COUNTIES.
&&
HENTZ
.PREV DISCUSSION... /ISSUED 316 PM CST WED DEC 14 2011/
TONIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SHEARED VORT MAX STRETCHING FROM NORTHEAST NEW MEXICO TO EASTERN
NEBRASKA APPARENT IN 1945Z WATER VAPOR IMAGERY AND RUC ANALYSIS.
RAIN SPREAD BACK INTO SOUTHERN WI EARLY THIS AFTERNOON...SUPPORTED
BY 500MB VORT MAX PUSHING INTO SOUTH CENTRAL WI...WARM AIR ADVECTION
AND CONTINUED ISENTROPIC LIFT. OMEGA VALUES WILL ALSO INCREASE
BETWEEN NOW AND 7 PM AS WELL...PER RUC AND NAM MODEL SNDGS.
REGIONAL RADAR NOW ROUGHLY SHOWING DRY SLOT MOVING INTO CENTRAL
IOWA...CORRESPONDING TO THE CENTER OF SFC LOW PRESSURE. OBS STILL
SHOWING DRIZZLE IN THE VICINITY. SFC LOW WILL MOVE INTO NORTHEAST
IOWA AROUND 00Z...AND CLIP THE NORTHWEST FORECAST AREA AS IT MOVES
ACROSS CENTRAL WI AT 03Z. THE SFC TROUGH/COLD FRONT WILL THEN TREK
ACROSS SOUTHEAST WI FROM 05Z TO 09Z...USHERING IN COLDER AND DRIER
AIR...AS THE SFC LOW MOVES INTO EASTERN UPPER MICHIGAN. LOW LEVELS
WILL REMAIN MOIST BEHIND THE FRONT...BUT DRY OUT ALOFT...THUS
CAUSING DRIZZLE BEHIND THE DEPARTING LOW THROUGH AROUND 15Z/9AM THU
MORNING.
THE BAGGY PRESSURE GRADIENT OVER THE WESTERN FORECAST AREA WILL
ALLOW FOR AREAS OF DENSE FOG THROUGH LATE EVENING UNTIL THE COLD
FRONT COMES THROUGH AND THE WINDS INCREASE. DENSE FOG ADVY POSTED.
TEMPERATURES WILL KEEP RISING THROUGH THE EVENING...REACHING OUR
DAILY HIGH IN THE UPPER 40S/LOWER 50S AROUND MIDNIGHT. TEMPS WILL
GRADUALLY FALL THROUGH THE DAY THU...DROPPING DOWN TO AROUND
FREEZING FROM NW TO SE DURING THE AFTERNOON HOURS.
PRECIP IS EXPECTED TO END BY LATE THU MORNING...AND CLOUDS SHOULD
BREAK UP DURING THE AFTERNOON HOURS...BECOMING PARTLY CLOUDY BY
EVENING.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE IS HIGH.
SKIES CONTINUE TO CLEAR OUT EARLY THURSDAY EVENING AS THE LOW
PULLS AWAY AND HIGH PRESSURE BUILDS IN. THINGS COOL DOWN...BUT
REMAIN AT OR SLIGHTLY ABOVE NORMAL.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS MEDIUM.
A COUPLE OF WEAK MID LEVEL SHORT WAVES COME THROUGH THE FAST
NORTHWEST FLOW FRIDAY NIGHT AND AGAIN SATURDAY AFTERNOON. MOISTURE
BEGINS TO RETURN AND THERE IS SOME INDICATION WE COULD GET ENOUGH
COLUMN SATURATION TO SQUEEZE OUT A FEW FLAKES OF SNOW. HAVE
INTRODUCED A SLIGHT CHANCE OF LIGHT SNOW...BUT LITTLE OR NO
ACCUMULATION IS EXPECTED. THE GFS AND THE NAM ARE HINTING AT SOME
VERY LIGHT QPF THROUGH THIS PERIOD.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
QUIET CONDITIONS EXPECTED THIS PERIOD AS WEAK RIDGING MOVES
THROUGH. TEMPS REMAIN AT OR ABOVE NORMAL.
SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE IS LOW.
THERE IS MAJOR MODEL UNCERTAINTY FOR EARLY NEXT WEEK. AT ISSUE IS
WHETHER WE/LL SEE A LOW MOVE UP INTO THE GREAT LAKES AND GIVE US
RAIN...OR STAY WELL TO THE SOUTH AND KEEP US DRY...OR TAKE A
COMPROMISE OF THE TWO AND POSSIBLY GIVE US SOME ACCUMULATING SNOW.
THE GFS HAS MAINTAINED IT/S SOUTHERN DRY SOLUTION FOR US...THE
CANADIAN LOOKS FAIRLY WARM/RAINY WITH A LOW MOVING INTO THE
CENTRAL GREAT LAKES...WHILE THE ECMWF IS A COMPROMISER TAKING A
LOW THROUGH CENTRAL ILLINOIS/INDIANA. THE ECMWF WOULD BE COOLER
DURING THE PRECIP AND THIS COULD RESULT IN SOME ACCUMULATING
SNOW...NOTHING MAJOR AT THIS POINT. THE MODELS ARE HAVING A VERY
DIFFICULT TIME PHASING ENERGY FROM THE SOUTHERN AND NORTHERN
STREAMS. HAVE KEPT POPS IN THE CHC CATEGORY UNTIL WE GET A LITTLE
MORE CONSENSUS.
AVIATION/00Z TAFS/...SURFACE LOW PRESSURE WILL TRACK ACROSS
NORTHEAST IOWA...CENTRAL WI AND EASTERN UPPER MICHIGAN THROUGH
TONIGHT. BAGGY PRESSURE GRADIENT BENEATH THE SFC LOW WILL COVER
SOUTH CENTRAL WI...ALLOWING AREAS OF DENSE FOG TO DEVELOP/PERSIST
THROUGH THE EVENING.
RAIN ASSOCIATED WITH THE 500MB SHORTWAVE...850MB WARM AIR
ADVECTION...AND STRONG OMEGA WILL DIMINISH AS THE SFC LOW COMES
OVERHEAD...AS THE DRY SLOT HITS THE REGION.
COLD FRONTAL PASSAGE WILL OCCUR BETWEEN 05Z AND 08Z TONIGHT. STRONG
COLD ADVECTION THU AM WILL IMPROVE CONDITIONS BY RAISING THE
CEILINGS AND IMPROVING VISIBILITY. WIND GUSTS TO 30 KNOTS
POSSIBLE...ESPECIALLY AT MKE. CLOUDS SHOULD SCATTER OUT DURING THU
AFTERNOON.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 6 PM TNT THROUGH
9 PM THU EVENING. BREEZY SSWLY WINDS AND HIGH WAVES WILL DEVELOP
THIS EVENING WITH A COLD FRONTAL PASSAGE EXPECTED TO SHIFT THE WINDS
TO THE WEST BY 09Z TNT. STRONG COLD ADVECTION WILL COMBINE WITH THE
RELATIVELY MILD LAKE MI WATER TEMPS TO PRODUCE UNSTABLE CONDITIONS
IN THE LOW LEVEL ATMOSPHERE. THIS WILL ENHANCE THE ALREADY MODERATE
WIND FIELD WITH WIND GUSTS EXPECTED TO REACH 30 KTS. THE WAVES WILL
DECREASE AFTER COLD FROPA DUE TO THE WLY COMPONENT OF THE WIND AND
THEREFORE LESS FETCH TO GENERATE WAVES. HOWEVER...HIGH WAVES WILL
STILL OCCUR OVER THE OPEN WATERS OF LAKE MI. THE WINDS WILL SUBSIDE
BY LATE THU EVENING AS A LARGE HIGH PRESSURE AREA APPROACHES FROM
THE WEST.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR WIZ046-047-056-
057-062-063-067-068.
DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ051-058.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THURSDAY FOR LMZ643>646.
&&
$$
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
327 PM CST TUE DEC 13 2011
.VERY SHORT TERM...
TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWED A DEEP TROUGH OVER THE
WESTERN U.S...WITH A LARGE PLUME OF MOISTURE STRETCHING FROM TEXAS
THROUGH NORTHERN MISSOURI. SHORTWAVE EJECTING OUT OF THE SW UPPER
LOW WILL BRING A SFC LOW FROM THE PLAINS THROUGH IOWA ON WED. FIRST
ROUND OF PRECIPITATION WILL BEGIN ALREADY TONIGHT ON THE NOSE OF THE
LOW LEVEL JET AND AN INITIAL WEAK SHORTWAVE OUT AHEAD OF THE MAIN
TROUGH. STRONG ISENTROPIC LIFT ALONG THIS SURGE OF WARM AND MOIST
AIR WILL ALLOW FOR MODERATE RAIN OVERNIGHT THROUGH EARLY WED
MORNING.
MODELS SLOWED DOWN THE ONSET OF THE PRECIP...SO BACKED OFF POPS A
BIT IN THE 03Z-06Z TIME RANGE. PRECIP FOR THE FIRST ROUND COULD
APPROACH A QUARTER INCH.
A LULL IN THE STEADY PRECIP IS EXPECTED DURING THE MORNING HOURS ON
WED. THE INITIAL WAA AND ISENTROPIC LIFT WILL BE TO THE NORTH OF THE
FORECAST AREA...AND THE WARM FRONTAL PRECIP WILL STILL BE SOUTH OF
THE WI/IL BORDER. DURING THIS LULL...THERE MAY BE SOME AREAS OF FOG
AND MUCH LOWER CLOUDS.
THEN THE SECOND ROUND OF PRECIP WILL COME IN EITHER LATE MORNING OR
EARLY AFTERNOON ON WED...TIMING STILL UNCERTAIN. STRONG DYNAMICS
WITH THIS SURGE OF MOISTURE...SINCE THE 500MB TROUGH AND SFC LOW
WILL BE APPROACHING...ALONG WITH THE SFC AND 850MB WARM FRONT. WITH
THE STRONG FORCING...ISOLATED THUNDER NOT OUT OF THE QUESTION. KEPT
THE SCHC THUNDER MENTION IN THE AFTERNOON. UP TO A HALF INCH OF RAIN
POSSIBLE WITH THIS SECOND ROUND. TEMPS EXPECTED TO RISE INTO THE
MID/UPPER 40S WITH THE FRONT LATE WED AFTERNOON.
.SHORT TERM...WEDNESDAY NIGHT THROUGH FRIDAY.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO
HIGH.
SOUTHERLY FLOW AHEAD OF THE SURFACE LOW BRINGS THERMAL RIDGE INTO
THE SOUTHEAST THAT WILL ALLOW TEMPERATURES TO CLIMB TO THE LOW 50S.
MAIN AREA OF PRECIPITATION WILL END FROM WEST TO EAST AFTER 06Z
THURSDAY WITH SUBSIDENCE BEHIND 500 MB AND SURFACE TROUGHS.
OMEGA AHEAD OF SECOND NORTHERN STREAM SHORT WAVE MAINLY FOCUSED TO
THE NORTH WITH THE STRONGEST 700-500MB FRONTOGENETIC RESPONSE DURING
THE DAY THURSDAY. COLDER AIR HOLDS OFF UNTIL PASSAGE OF THIS SECOND
WAVE...SO EXPECT ANY LINGERING PRECIPITATION THURSDAY TO BE VERY
LIGHT RAIN OR DRIZZLE...WITH DRYING IN THE DENDRITE GROWTH ZONE
PREVENTING CRYSTAL FORMATION AND SNOW. EARLY DAYTIME HIGH
TEMPERATURES AROUND 12-13Z THURSDAY THEN COOLING THROUGH THE DAY.
ANY LIGHT PRECIPITATION SHOULD END BY 18Z.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SURFACE HIGH PRESSURE BUILDS OVER FOR THURSDAY NIGHT AND FRIDAY.
CLEARING SKIES THURSDAY NIGHT...BUT WINDS WILL TAKE A BIT LONGER TO
LIGHTEN/DECOUPLE OVERNIGHT. LOWS AROUND 20 NORTHWEST...TO MID 20S
ALONG THE LAKE. -5C TO -6C 925 MB TEMPERATURES SUPPORT LOW TO MID 30
HIGHS FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FORECAST CONFIDENCE LOW
TO MEDIUM.
NORTHWEST TO SOUTHEAST MOVING SHORT WAVE CROSSES REGION FRIDAY
NIGHT/SATURDAY...BUT DRY LOWER LAYERS WILL PREVENT
MEASURABLE...THOUGH A FEW FLURRIES ARE POSSIBLE. WILL LEAVE ANY
PRECIPITATION MENTION OUT FOR NOW. DRY NORTHWEST FLOW WITH NORMAL
TEMPERATURES SATURDAY...BEGINS TO BACK WEST SUNDAY AND THEN
SOUTHWEST MONDAY AS NEXT SYSTEM EJECTS OUT OF THE SOUTHWEST U.S.
INTO THE CENTRAL PLAINS. WHILE MODELS DIFFER ON EXACTING
DETAILS...EARLY TREND IS TO TAKE SURFACE LOW ACROSS ILLINOIS AND
INDIANA MONDAY NIGHT/TUESDAY...WITH SOUTHERN WISCONSIN ON THE
NORTHERN EDGE OF THE PRECIPITATION SHIELD. WARMTH PUSHING BACK NORTH
AHEAD OF LOW WILL BRING A MAINLY RAIN/SNOW MIX...CHANGING TO ALL
SNOW AFTER LOW PASSAGE. WILL HAVE TO WATCH FOR ACCUMULATING SNOW
POTENTIAL IF PROFILE TEMPERATURES COO MORE THAN CURRENTLY
INDICATED.
&&
.AVIATION/00Z TAFS/...VFR CIGS WILL SLOWLY LOWER AS SOUTH WINDS
SLOWLY INCREASE LOW LEVEL MOISTURE THIS EVENING. SLOWED THE TIMING
OF THIS LOWERING TO EARLY EVENING. MVFR CIGS WILL DEVELOP FROM WEST
TO EAST ACROSS THE CWA DURING THE AFTERNOON INTO THE EARLY EVENING.
RAIN VIA WARM...MOIST ADVECTION WILL THEN ARRIVE AT THE TAF SITES BY
AROUND MIDNIGHT AND CONTINUE INTO WED. CIGS WILL FALL TO LIFR WITH
THE RAIN AND SATURATION OF THE LOW LEVEL ATMOSPHERE WHILE VSBYS WILL
FALL TO IFR.
THERE SHOULD BE A PERIOD OF TIME WED MORNING WHERE THERE IS A LULL
IN THE STEADY RAIN...WHICH WOULD ACTUALLY DIMINISH VISIBILITY AND
LOWER THE CEILING HEIGHTS. NOT SURE OF EXACT TIMING OF THIS
LULL...THEN RAIN WILL INCREASE ONCE AGAIN EARLY WED AFTERNOON AS THE
MAIN UPPER AND SFC LOW APPROACH SOUTHERN WI. THE SECOND ROUND OF
RAIN IS EXPECTED TO BE HEAVIER THAN THE FIRST...AND THE STRONG
FORCING SHOULD ALLOW FOR SOME ISOLATED THUNDER.
&&
.MARINE...INCREASING SOUTHERLY WINDS WILL ALLOW FOR BUILDING WAVES
TO NEAR-SMALL CRAFT ADVISORY CRITERIA WED AFTERNOON. WAVE MODEL FCST
WAVE HEIGHTS UP TO 3 TO 4 FEET...SO HELD OFF ON ISSUING A SMALL CRAFT
ADVY. WEST WINDS BEHIND THE DEPARTING LOW ON THU WILL INCREASE...AND
WIND GUSTS TO 25 KNOTS ARE POSSIBLY/LIKELY WITH THE COLD AIR
ADVECTION. SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC
WEDNESDAY NIGHT THROUGH TUESDAY...REM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1217 PM CST TUE DEC 13 2011
.UPDATE...
WIDESPREAD CLOUDS ACROSS THE ENTIRE UPPER MIDWEST TODAY DUE TO
PERSISTENT BUT WEAK WARM AIR ADVECTION...THE LEFT EXIT REGION OF THE
UPPER JET...AND WEAK SHORTWAVES. PER THE LATEST MODEL AND MOS
GUIDANCE...DECREASED MAX TEMPS AROUND MARQUETTE/GREEN LAKE AND SAUK
COUNTIES A COUPLE OF DEGREES. OTHERWISE NO OTHER CHANGES FOR THE
TODAY PERIOD.
12Z NAM CAME IN A LITTLE SLOWER WITH THE ONSET OF THE QPF...BUT
BUFKIT SNDGS STILL SHOW FULL COLUMN SATURATION AT MSN AT 06Z. RUC IS
ABOUT AN HOUR LATER WITH THE SATURATION. WILL PROBABLY STICK CLOSE
TO THE PREVIOUS FORECAST...SINCE PRECIP SHOULD BEGIN FALLING RIGHT
WHEN COLUMN SATURATION OCCURS.
&&
.AVIATION/18Z TAFS/...VFR CIGS WILL SLOWLY LOWER AS SOUTH WINDS
SLOWLY INCREASE LOW LEVEL MOISTURE THIS AFTERNOON INTO EARLY THIS
EVENING. SLOWED THE TIMING OF THIS LOWERING TO MID AFTERNOON RATHER
THAN RIGHT AT 18Z. MVFR CIGS WILL DEVELOP FROM WEST TO EAST ACROSS
THE CWA DURING THE AFTERNOON INTO THE EARLY EVENING. RAIN VIA
WARM...MOIST ADVECTION WILL THEN ARRIVE AT THE TAF SITES BY LATE
EVENING AND CONTINUE INTO WED. CIGS WILL FALL TO LIFR WITH THE RAIN
AND SATURATION OF THE LOW LEVEL ATMOSPHERE WHILE VSBYS WILL FALL TO
IFR.
THERE SHOULD BE A PERIOD OF TIME WED MORNING WHERE THERE IS A LULL
IN THE STEADY RAIN...WHICH WOULD ACTUALLY DIMINISH VISIBILITY AND
LOWER THE CEILING HEIGHTS. NOT SURE OF EXACT TIMING OF THIS
LULL...THEN RAIN WILL INCREASE ONCE AGAIN EARLY WED AFTERNOON AS THE
MAIN UPPER AND SFC LOW APPROACH SOUTHERN WI.
&&
.MARINE...INCREASING SOUTHERLY WINDS WILL ALLOW FOR BUILDING WAVES
TO NEAR-SMALL CRAFT ADVISORY CRITERIA WED AFTERNOON. WEST WINDS
BEHIND THE DEPARTING LOW ON THU WILL INCREASE...AND WIND GUSTS TO 25
KNOTS ARE POSSIBLY/LIKELY WITH THE COLD AIR ADVECTION. SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED. NEED TO PIN DOWN EXACT TIMING AFTER
RUNNING THE WAVE MODEL...AND THEN EXPECT A HEADLINE WITH THE
AFTERNOON ISSUANCE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 AM CST TUE DEC 13 2011
.SHORT TERM...TODAY THROUGH THURSDAY
342 AM CST TUE DEC 13 2011
FOCUS TODAY IS ON DENSE FOG ACROSS NORTH CENTRAL WISCONSIN THIS MORNING.
FORECAST CONCERNS THEN TURN TO STORM SYSTEM IMPACTING THE AREA
TONIGHT THROUGH THURSDAY MORNING.
CURRENT SURFACE OBSERVATIONS SHOW DENSE FOG ACROSS NORTH CENTRAL
WISCONSIN. A DENSE FOG ADVISORY HAS BEEN ISSUED FOR CLARK AND
TAYLOR COUNTIES THROUGH 9AM THIS MORNING. PATCHY FOG WAS REPORTED
ACROSS PORTIONS OF SOUTHEAST MINNESOTA THROUGH WEST CENTRAL
WISCONSIN. CURRENT WATER VAPOR IMAGERY SHOWED A POTENT UPPER LEVEL
TROUGH MOVING ACROSS THE SOUTHWEST...WITH MOISTURE STREAMING
NORTHWARD ACROSS THE SOUTHERN AND CENTRAL PLAINS.
CLOUDY SKIES CAN BE EXPECTED ACROSS THE AREA TODAY AS LOW LEVEL
MOISTURE REMAINS IN PLACE ACROSS THE REGION. AREAS OF FOG WILL
LINGER ACROSS WEST CENTRAL THROUGH NORTH CENTRAL WISCONSIN EARLY
THIS MORNING. LIGHT SOUTHEAST WINDS ARE EXPECTED TO DEVELOP LATER
THIS MORNING AND SHOULD ADVECT SLIGHTLY DRIER AIR INTO THE REGION
WITH FOG GRADUALLY DISSIPATING. BE ALERT FOR DENSE FOG THIS
MORNING ACROSS NORTH CENTRAL WISCONSIN...WHERE VISIBILITIES COULD
BE REDUCED TO AROUND ONE QUARTER OF A MILE AT TIMES. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE THE MID 30S ACROSS NORTH
CENTRAL WISCONSIN TO THE LOWER 40S ACROSS PORTIONS OF NORTHEAST
IOWA THROUGH SOUTHWEST WISCONSIN. AN UPPER LEVEL TROUGH WILL MOVE
FROM THE SOUTHWEST CONUS INTO THE SOUTHERN PLAINS TODAY...WITH
PRECIPITATION SPREADING ACROSS THE SOUTHERN/CENTRAL PLAINS. A WARM
FRONT CURRENTLY POSITIONED FROM SOUTHWEST KANSAS EAST INTO THE
OHIO RIVER VALLEY REGION WILL LIFT NORTHWARD THROUGH THE DAY TODAY.
THE WARM FRONT IS EXPECTED TO BE POSITIONED ACROSS SOUTHERN IOWA
INTO NORTHERN ILLINOIS BY THIS EVENING.
THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO THE FORECAST AREA LATE
TONIGHT INTO EARLY WEDNESDAY MORNING. LOOK FOR RAIN TO SPREAD ACROSS
THE AREA TONIGHT...POSSIBLY MIXING WITH SNOW ACROSS NORTH CENTRAL
AND CENTRAL WISCONSIN WHERE FORECAST SOUNDINGS SUPPORT SNOW BEFORE
THE WARM AIR ALOFT MOVES IN. TEMPERATURES WILL GRADUALLY WARM
OVERNIGHT AS THE WARM FRONT LIFTS NORTH ACROSS THE AREA. THE RAIN
WILL SPREAD INTO NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN DURING
THE EVENING HOURS...THEN SPREAD NORTHWARD AFTER MIDNIGHT. VERY
MOIST AIR WILL MOVE INTO THE AREA BEHIND THE WARM FRONT LATE
TONIGHT INTO WEDNESDAY MORNING...WITH PRECIPITABLE WATER VALUES
INCREASING TO AROUND 340 PERCENT OF NORMAL. FORECAST SOUNDINGS ARE
SHOWING ELEVATED CAPE ACROSS MUCH OF THE FORECAST AREA WEDNESDAY
MORNING INTO WEDNESDAY AFTERNOON. LIFTING FROM 780 MB YIELDS
AROUND 200 J/KG LATE WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON.
WOULD EXPECT TO SEE A FEW LIGHTING STRIKES THROUGH THE DAY ON
WEDNESDAY...SO HAVE ADDED THUNDER MENTION TO THE FORECAST.
DEEPENING ON HOW MUCH WARMING IS REALIZED WITHIN THE WARM
LAYER...COULD SEE SOME SMALL HAIL MAKE IT TO THE SURFACE IN ANY
CONVECTION THAT DEVELOPS. RAINFALL AMOUNTS ON WEDNESDAY WILL RANGE
FROM A QUARTER OF AN INCH ACROSS PORTIONS OF SOUTHEAST MINNESOTA
THROUGH NORTH CENTRAL WISCONSIN...TO AROUND THREE QUARTERS OF AN
INCH ACROSS MUCH OF NORTHEAST IOWA THROUGH SOUTHWEST WISCONSIN.
MODELS ARE SHOWING STRONG ISENTROPIC LIFT ON THE 280 THROUGH 315 K
SURFACE WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON...SO SHOULD
SEE RAINFALL ACROSS THE ENTIRE AREA THROUGH MUCH OF THE DAY. LOOK
FOR HIGH TEMPERATURES TO RANGE FROM THE UPPER 30S ACROSS NORTH
CENTRAL WISCONSIN TO THE MID TO UPPER 40S ACROSS NORTHEAST IOWA.
THE UPPER LEVEL TROUGH WILL LIFT INTO THE UPPER MISSISSIPPI RIVER
VALLEY WEDNESDAY EVENING. MODELS ARE SHOWING DIFFERENCES REGARDING
THE TRACK OF THE SURFACE LOW AS IT MOVES ACROSS THE REGION WEDNESDAY
EVENING. THE GFS TAKES THE LOW ACROSS NORTHEAST IOWA INTO NORTHEAST
WISCONSIN...WHILE THE NAM TAKES THE LOW ACROSS NORTHWEST IOWA AND
LIFTING IT NORTHEAST TO WESTERN LAKE SUPERIOR. IF THE NAM SOLUTION
HOLDS...PRECIPITATION WILL END ACROSS MUCH OF THE FORECAST AREA
EARLY WEDNESDAY EVENING. FORECAST SOUNDINGS SHOW DRIER AIR MOVING IN
ALOFT WEDNESDAY NIGHT AS THE LOW LIFTS NORTHEAST OF THE FORECAST
AREA AND A COLD FRONT MOVES IN FROM THE NORTHWEST. DEPENDING ON HOW
QUICKLY SURFACE TEMPERATURES COOL...COULD SEE A PERIOD OF FREEZING
DRIZZLE/DRIZZLE LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
RAIN SHOULD SWITCH OVER TO LIGHT SNOW OR POSSIBLY DRIZZLE/FREEZING
DRIZZLE AS COLDER AIR MOVES IN LATE IN THE NIGHT INTO THE EARLY
MORNING HOURS. STRONG COLD AIR ADVECTION WILL SET UP ACROSS THE
AREA EARLY ON THURSDAY BEHIND THE COLD FRONT. STRONG NORTHWEST
WINDS WILL DEVELOP EARLY ON THURSDAY....WITH SPEEDS OF 20 TO 25
MPH EXPECTED AND GUSTS TO AROUND 35 MPH POSSIBLE. IF DEEPER MIXING
IS REALIZED...A WIND ADVISORY MAY BE NEEDED ACROSS THE OPEN AREAS
OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. TEMPERATURES WILL FALL
THROUGH THE DAY ON THURSDAY. LOOK FOR HIGHS IN THE LOWER 30S EARLY
IN THE MORNING...WITH TEMPS FALLING INTO THE LOWER 20S BY LATE
AFTERNOON INTO THE EARLY EVENING. COOL HIGH PRESSURE WILL SETTLE
OVER THE AREA THURSDAY NIGHT WITH MOSTLY CLEAR SKIES EXPECTED.
LOOK FOR LOWS TO FALL INTO THE TEENS.
.LONG TERM...FRIDAY THROUGH MONDAY
342 AM CST TUE DEC 13 2011
13.00 MEDIUM RANGE MODELS IN REASONABLE AGREEMENT FRIDAY INTO
SATURDAY WITH COOL HIGH PRESSURE IN PLACE ACROSS THE REGION
PROVIDING QUIET CONDITIONS. LOOK FOR HIGHS ON FRIDAY AND SATURDAY TO
RANGE FROM THE UPPER 20S TO LOWER 30S...WITH LOWS IN THE TEENS
FRIDAY NIGHT...WARMING INTO THE 20S SATURDAY NIGHT. WARMER AIR IS
EXPECTED TO MOVE BACK INTO THE REGION SATURDAY NIGHT THROUGH
SUNDAY...WITH 850 MB TEMPERATURES WARMING TO AROUND 4 C. HIGHS ON
SUNDAY ARE EXPECTED TO CLIMB BACK INTO THE 30S. MODELS ARE SHOWING
DIFFERING SOLUTIONS ON SUNDAY NIGHT INTO MONDAY. THE GFS SHOWS AN
UPPER LEVEL LOW MOVING FROM THE FOUR CORNER REGION INTO THE CENTRAL
PLAINS DURING THIS TIME FRAME...THEN MOVING INTO THE UPPER MISSISSIPPI
RIVER VALLEY ON MONDAY. THE ECMWF KEEPS THIS SYSTEM WELL TO THE
SOUTH AND TAKES IT FROM SOUTHWEST INTO THE SOUTHERN PLAINS. CHOSE TO
GO WITH A MODEL CONSENSUS BLEND APPROACH FOR PRECIPITATION CHANCES
DURING THIS TIME FRAME...WITH A CHANCE OF SNOW LATE SUNDAY NIGHT
THROUGH MONDAY. THE SNOW MAY MIX WITH RAIN DURING THE DAY ON MONDAY.
WILL HAVE TO CLOSELY MONITOR THIS SYSTEM THE NEXT FEW MODEL RUNS.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1109 PM CST MON DEC 12 2011
BIG CONCERN FOR THE OVERNIGHT PERIOD IS WHETHER THE CEILINGS AND
VISIBILITY WILL GO TO IFR CONDITIONS. THE 13.03Z RUC AND 13.00Z
NAM BUFKIT SOUNDINGS SHOW A LARGE DRY WEDGE JUST ABOVE THE SURFACE
WITH SATURATION OCCURRING AGAIN BETWEEN 2 AND 3KT FEET. THIS IS
EXACTLY WHERE THE CEILINGS HAVE BEEN SETTING ALL NIGHT AND THE 00Z
KDVN AND KMPX SOUNDING SUPPORT THE EXISTENCE OF THIS DRY LAYER
OVER THE AREA. THAT WOULD ALSO EXPLAIN THE GENERAL LACK OF FOG
DESPITE THE RECENT PRECIPITATION AND HAVING SURFACE TEMP/DEW
POINT SPREADS OF 3 DEGREES OR LESS. THESE BUFKIT SOUNDINGS
SUGGESTS THIS DRY WEDGE WILL REMAIN IN PLACE PAST SUNRISE BEFORE
ERODING. CONFIDENCE ON THIS TIMING IS NOT HIGH SO HAVE BACKED OUT
OF IFR CONDITIONS FOR BOTH SITES BUT STILL INDICATE SOME FOG
FORMING TAKING VISIBILITIES DOWN TO MVFR WITH THE CEILING HOLDING
STEADY THROUGH THE NIGHT. WITH A VERY LIGHT FLOW TUESDAY...MAY NOT
BE MUCH CHANGE OTHER THAN THE LIGHT FOG DISSIPATING AS THE FLOW
SLOWLY STARTS TO INCREASE AHEAD OF THE NEXT SYSTEM. BOTH THE NAM
AND GFS SUGGEST SOME POTENTIAL FOR RAIN TO MOVE INTO BOTH TAF
SITES RIGHT AROUND 14.06Z TUESDAY OR SHORTLY AFTER. FOR NOW WILL
STAY WITH A DRY FORECAST THROUGH 14.06Z BUT NEXT SET OF FORECASTS
WILL HAVE TO INCLUDE THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE DEC 13 2011
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1109 PM CST MON DEC 12 2011
.SHORT TERM...TONIGHT THROUGH THURSDAY
230 PM CST MON DEC 12 2011
FORECAST CONCERNS FOCUS ON THE NEXT WEATHER SYSTEM TO IMPACT THE
AREA TUE NIGHT-WED NIGHT...LOOKING MOSTLY RAIN.
TONIGHT...UPPER LEVEL SHORTWAVE TROUGH CONTINUES OFF TO THE
EAST...WITH SOME LINGERING ISENTROPIC UPGLIDE THROUGH THE LOW
SATURATION THIS EVENING. BUFKIT SOUNDINGS POINT TO SOME SHALLOWING
OF THE MOISTURE...WITH NO ICE IN THE CLOUD. DRIZZLE SHOULD BE THE
PCPN TYPE FOR WHATEVER FALLS. WITH THE BROADSCALE THERMODYNAMIC LIFT
EXITING OVERNIGHT...BELIEVE THE THREAT FOR SOME LIGHT DRIZZLE SHOULD
TOO. SFC TEMPS LOOK TO STAY ABOVE FREEZING...AND DON/T ANTICIPATE
MUCH/IF ANY FREEZING DRIZZLE AT THIS TIME. THAT SAID...SOME
LOCATIONS IN COLDER DRAINAGE AREAS COULD STILL HAVE A MINOR THREAT
OF ICING THIS EVENING.
UPPER LEVEL TROUGH CURRENTLY OVER THE WEST COAST IS PROGGED TO LIFT
NORTHEAST ACROSS THE PLAINS TUE NIGHT/WED...MOVING OVER THE UPPER
MISSISSIPPI RIVER AS AN OPEN WAVE WED NIGHT. MEANWHILE SHORTWAVE
TROUGH IN THE NORTHERN STREAM WILL SPIN OVER THE NORTHERN GREAT
LAKES EARLY THU. THE MODELS HAVE HAD A VARIETY OF SOLUTIONS OVER THE
PAST FEW DAYS...LOWERING FORECAST CONFIDENCE IN TIMING/POSITIONING.
THIS GO AROUND THOUGH THE GFS/EC SOLUTIONS ARE MUCH CLOSER WITH THE
MAIN FORECAST FEATURES. THE NAM REMAINS QUICK...WITH A STRONGER
NORTHERN SHORTWAVE LIKELY RESULTING IN ITS SFC LOW PULLING/DEEPENING
FARTHER NORTH AS A RESULT. OVERALL THOUGH...NOT SURE THE DIFFERENCES
WILL HAVE A BIG IMPACT ON THE SENSIBLE WEATHER...OTHER THAN
START/END TIMES...AS ALL POINT TO RAIN BEING THE PREDOMINANT PCPN
TYPE DURING THE LIFE OF THE EVENT.
OUT AHEAD OF THE HEART OF THIS NEXT WEATHER SYSTEM LOW LEVEL WARM
AIR ADVECTION/ISENTROPIC UPGLIDE WILL SPREAD ACROSS THE REGION FROM
THE SOUTH TUE NIGHT...WITH THE NOSE OF THE 850 MB MOISTURE TRANSPORT
POINTING INTO SOUTHERN WI BY 12Z WED. MID LEVEL FRONTOGENETIC
RESPONSE /700-500 MB/ OVERNIGHT. EXPECT A BLOSSOMING/ADVECTING AREA
OF PRECIPITATION TO SPREAD ACROSS THE AREA OVERNIGHT TUE AS A
RESULT. COULD BE A SMALL BREAK/LESSENING IN AREAL EXTENT OF PCPN
LATER WED MORNING...BUT THIS SHOULD FILL BACK IN AS THE SHORTWAVE
AND SFC LOW MOVE INTO SOUTHERN WI WED EVENING. GOOD SLOPING
FRONTOGENETIC RESPONSE NORTHWEST OF THE LOW...BUT AGAIN...MOSTLY
CONFINED TO THE MID LEVELS OF THE ATMOSPHERE.
AS MENTIONED EARLIER...IT LOOKS LIKE A RAIN EVENT FOR THE REGION.
NORTHWEST-SOUTHEAST RUNNING TIME/HEIGHT X-SECTIONS AND BUFKIT
SOUNDINGS POINT TO AN INCREASING WARM LAYER FROM AROUND 800 MB TO
THE SFC FROM 00Z WED THROUGH 06Z THU. THIS DEEP WARM LAYER WILL
RESULT IN RAIN. SOME HINTS THAT LOCATIONS TO THE NORTH/NORTHWEST
COULD START OUT AS A RAIN OR RAIN/SNOW MIX...BUT DON/T THINK THIS
WOULD LAST LONG. ON THE BACKSIDE...IN THE DEFORMATION REGION AS THE
STORM SYSTEM EXITS TO THE EAST...COLD AIR WILL BE RETURNING. A
CHANGE OVER TO RAIN/SNOW OR SNOW COULD OCCUR WED NIGHT BEFORE ALL
THE PCPN EXITS NORTHEAST...MOSTLY FOR LOCATIONS ALONG AND NORTH OF
AN AUSTIN TO BLACK RIVER FALLS LINE. THERE COULD BE SOME MINOR
ACCUMULATIONS AT THIS TIME.
THE SFC PRESSURE GRADIENT TIGHTENS POST THE SYSTEM ON THU...WITH A
TROP FOLD DOWN TO 800 MB VIA THE GFS AND EC. VERT WIND PROFILE
UNI-DIRECTIONAL THROUGH A SIZABLE PORTION OF THE LOWER
ATMOSPHERE...AND RH FIELDS POINT TO QUICK CLEARING TO THE WEST. THU
SHOULD BE A RATHER WINDY DAY...AND SOME SIGNALS SUGGEST THAT A WIND
ADV COULD BE NEEDED FOR THE WINDER/OPEN AREAS OF SOUTHEAST MN AND
NORTHEAST IA. SOMETHING TO WATCH.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
230 PM CST MON DEC 12 2011
HIGH PRESSURE WORKS IN FOR FRI/SAT...WITH DRY CONDITIONS FAVORED AS
A RESULT. MODEL DIFFERENCES CREEP UP AGAIN FOR SUN/MON THOUGH AS THE
EC WOULD SLIDE AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE NORTHERN
GREAT LAKES SUN...WHILE THE GFS IS MORE ACTIVE IN THE SOUTHERN
STREAM...BRINGING A SHORTWAVE UP FROM THE PLAINS SUN NIGHT/MON.
CONFIDENCE LOW IN THE DETAILS IN THIS PERIOD WITH SOME MARKEDLY
DIFFERENT SOLUTIONS. WILL LEAN ON THE CONSENSUS FOR NOW.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1109 PM CST MON DEC 12 2011
BIG CONCERN FOR THE OVERNIGHT PERIOD IS WHETHER THE CEILINGS AND
VISIBILITY WILL GO TO IFR CONDITIONS. THE 13.03Z RUC AND 13.00Z
NAM BUFKIT SOUNDINGS SHOW A LARGE DRY WEDGE JUST ABOVE THE SURFACE
WITH SATURATION OCCURRING AGAIN BETWEEN 2 AND 3KT FEET. THIS IS
EXACTLY WHERE THE CEILINGS HAVE BEEN SETTING ALL NIGHT AND THE 00Z
KDVN AND KMPX SOUNDING SUPPORT THE EXISTENCE OF THIS DRY LAYER
OVER THE AREA. THAT WOULD ALSO EXPLAIN THE GENERAL LACK OF FOG
DESPITE THE RECENT PRECIPITATION AND HAVING SURFACE TEMP/DEW
POINT SPREADS OF 3 DEGREES OR LESS. THESE BUFKIT SOUNDINGS
SUGGESTS THIS DRY WEDGE WILL REMAIN IN PLACE PAST SUNRISE BEFORE
ERODING. CONFIDENCE ON THIS TIMING IS NOT HIGH SO HAVE BACKED OUT
OF IFR CONDITIONS FOR BOTH SITES BUT STILL INDICATE SOME FOG
FORMING TAKING VISIBILITIES DOWN TO MVFR WITH THE CEILING HOLDING
STEADY THROUGH THE NIGHT. WITH A VERY LIGHT FLOW TUESDAY...MAY NOT
BE MUCH CHANGE OTHER THAN THE LIGHT FOG DISSIPATING AS THE FLOW
SLOWLY STARTS TO INCREASE AHEAD OF THE NEXT SYSTEM. BOTH THE NAM
AND GFS SUGGEST SOME POTENTIAL FOR RAIN TO MOVE INTO BOTH TAF
SITES RIGHT AROUND 14.06Z TUESDAY OR SHORTLY AFTER. FOR NOW WILL
STAY WITH A DRY FORECAST THROUGH 14.06Z BUT NEXT SET OF FORECASTS
WILL HAVE TO INCLUDE THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST MON DEC 12 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1019 AM MST TUE DEC 13 2011
.DISCUSSION...VISIBILITIES HAVE IMPROVED SOME OVER THE EAST PART OF
THE CWA AS OF 17Z. THAT TREND SHOULD CONTINUE THROUGH THE EARLY
AFTERNOON BEFORE THE FOG DISSIPATES. IN A RECENT UPDATE...HAVE
ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AND HAVE KEPT FOG IN THE
FORECAST FOR AREAS BELOW 4500 FEET MSL THROUGH 20Z.
.AVIATION...18Z TAF ISSUANCE...
IFR CEILINGS AND VISIBILITIES IN FOG WILL PERSIST THROUGH 20Z OVER
THE EAST PART OF THE CWA. RECENT TRENDS HAVE BEEN FOR THE CONDITIONS
TO SLOWLY IMPROVE AS BOUNDARY LAYER WINDS BECOME MORE SOUTHWESTERLY.
VFR CONDITIONS WILL BE OVER THE ENTIRE CWA BY 21Z. OVER MUCH OF
THE PANHANDLE...IFR CEILINGS AND VISIBILITIES IN FOG WILL RETURN
AFTER 04Z AND THEN IMPROVE AFTER 11Z. CLOUD DEPTH WILL AGAIN BE
QUITE SHALLOW TONIGHT AND VISIBILITIES PERHPAS NOT AS LOW TONIGHT
AS THRY WERE RECENTLY. VFR CONDITIONS WILL BE OVER THE ENTIRE CWA
AFTER 15Z. WEST TO NORTHWEST WINDS WILL GUST AS HIGH AS 30 KNOTS
OVER THE CWA AFTER 15Z AND CONTINUE THROUGH WEDNESDAY EVENING.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 901 AM MST TUE DEC 13 2011/...
.DISCUSSION...
FOG PERSISTS AT MID MORNING OVER THE EAST PART OF THE CWA. THE FOG
WAS DENSE IN PLACES OVER THE SOUTHERN PANHANDLE. THE DEPTH OF THE
LOW CLOUDS AND FOG WAS BETWEEN 500 AND 1500 FEET AS OF 15Z. THE
VISIBILITIES HAVE BEEN SLOWLY IMPROVING WITH INCREASED MIXING AND
A MORE SOUTHWEST BOUNDARY LAYER WIND. THE TIMING OF THE DENSE FOG
ADVISORY OF 17Z MAY WORK OUT WELL FOR THE SOUTHERN PANHANDLE. WILL
TAKE A CLOSER LOOK SOON IN REGARDS TO THE TIMING OF THE DISSIPATION
OF THE FOG. IN A RECENT UPDATE...ADJUSTED THE AREAS OF FOG THROUGH
MIDDAY AND ADJUSTED TEMPERATURES DOWN A BIT FOR THE PANHANDLE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 452 AM MST TUE DEC 13 2011/...
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
UPDATE...WEILAND
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
901 AM MST TUE DEC 13 2011
.DISCUSSION...
FOG PERSISTS AT MID MORNING OVER THE EAST PART OF THE CWA. THE FOG
WAS DENSE IN PLACES OVER THE SOUTHERN PANHANDLE. THE DEPTH OF THE
LOW CLOUDS AND FOG WAS BETWEEN 500 AND 1500 FEET AS OF 15Z. THE
VISIBILITIES HAVE BEEN SLOWLY IMPROVING WITH INCREASED MIXING AND
A MORE SOUTHWEST BOUNDARY LAYER WIND. THE TIMING OF THE DENSE FOG
ADVISORY OF 17Z MAY WORK OUT WELL FOR THE SOUTHERN PANHANDLE. WILL
TAKE A CLOSER LOOK SOON IN REGARDS TO THE TIMING OF THE DISSIPATION
OF THE FOG. IN A RECENT UPDATE...ADJUSTED THE AREAS OF FOG THROUGH
MIDDAY AND ADJUSTED TEMPERATURES DOWN A BIT FOR THE PANHANDLE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 452 AM MST TUE DEC 13 2011/...
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
UPDATE...WEILAND
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
452 AM MST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
448 AM MST TUE DEC 13 2011
.UPDATE FOR AVIATION DISCUSSION...
&&
.AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 435 AM MST TUE DEC 13 2011/
AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
435 AM MST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
233 AM MST TUE DEC 13 2011
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
.LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
.AVIATION...06Z TAF ISSUANCE...LIFR OR LOWER CONDITIONS IN STRATUS
AND FOG GRADUALLY SPREADING WESTWARD THROUGH THE WESTERN NEBRASKA
PANHANDLE PER SURFACE AND SATELLITE OBSERVATIONS. THIS DETERIORATING
TREND WILL CONTINUE OVERNIGHT. 00Z NAM AND SREF HAVE BACKED OFF ON
MVFR TO IFR CONDITIONS ACROSS SOUTHEAST WYOMING...BUT HRRR BRINGS
IN IFR TO A LUSK-PINE BLUFFS LINE AFTER 09Z. HAVE ADDED A TEMPO
GROUP FOR LOW END MVFR AT CHEYENNE BETWEEN 10Z AND 14Z. MODELS
MAINTAIN THESE IFR-LIFR CONDITIONS FOR THE PANHANDLE TERMINALS
THROUGH AT LEAST 18Z WHEN CEILINGS AND VISIBILITIES IMPROVE TO
MVFR. WINDS WILL REMAIN LIGHT...GENERALLY LESS THAN 10 KT...DURING
THE FORECAST PERIOD.
&&
.FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION/FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1044 PM MST MON DEC 12 2011
.AVIATION...06Z TAF ISSUANCE...LIFR OR LOWER CONDITIONS IN STRATUS
AND FOG GRADUALLY SPREADING WESTWARD THROUGH THE WESTERN NEBRASKA
PANHANDLE PER SURFACE AND SATELLITE OBSERVATIONS. THIS DETERIORATING
TREND WILL CONTINUE OVERNIGHT. 00Z NAM AND SREF HAVE BACKED OFF ON
MVFR TO IFR CONDITIONS ACROSS SOUTHEAST WYOMING...BUT HRRR BRINGS
IN IFR TO A LUSK-PINE BLUFFS LINE AFTER 09Z. HAVE ADDED A TEMPO
GROUP FOR LOW END MVFR AT CHEYENNE BETWEEN 10Z AND 14Z. MODELS
MAINTAIN THESE IFR-LIFR CONDITIONS FOR THE PANHANDLE TERMINALS
THROUGH AT LEAST 18Z WHEN CEILINGS AND VISIBILITIES IMPROVE TO
MVFR. WINDS WILL REMAIN LIGHT...GENERALLY LESS THAN 10 KT...DURING
THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 904 PM MST MON DEC 12 2011/
UPDATE...EVENING WATER VAPOR IMAGERY SHOWED THE UPPER LOW PRESSURE
SYSTEM SLIDING SOUTH OFF THE SOUTH CENTRAL CALIFORNIA COAST WITH
PACIFIC MOISTURE STREAMING NORTH-NORTHEAST INTO THE CENTRAL/SOUTHERN
ROCKIES AND GREAT BASIN. THE REGIONAL SURFACE ANALYSIS PLACED A
WEAK STATIONARY FRONT FROM THE SOUTHERN LARAMIE RANGE INTO EASTERN
COLORADO AND THEN NORTHEAST INTO SOUTHERN NEBRASKA. WEAK MOIST
SOUTHEASTERLY FLOW OVERRUNNING THE BOUNDARY WAS RESULTING IN AN
EXTENSIVE LOW STRATUS DECK FROM WESTERN SOUTH DAKOTA INTO THE
WESTERN NEBRASKA PANHANDLE. THE 01Z HRRR MODEL OUTPUT INDICATES
GRADUAL WESTWARD EXPANSION AND LOWERING OF THE STRATUS WITH
AREAS OF FREEZING FOG AFFECTING THE LEE OF THE LARAMIE RANGE AND
HIGH PLAINS OF SOUTHEAST WYOMING LATER TONIGHT. ALSO...BUFKIT AND
MODEL SOUNDING DATA SUGGESTS A GRADUAL DEEPENING OF A SUBFREEZING
LAYER JUST BELOW A PRONOUNCED LOW LEVEL INVERSION ACROSS THE
SOUTHEAST 1/4 OF THE CWA BY 12Z TUESDAY. HAVE UPDATED THE WEATHER
GRIDS TO INSERT PATCHY FREEZING DRIZZLE FOR THE SOUTHERN PORTIONS
OF THE WESTERN PANHANDLE TUESDAY MORNING. NOT EXPECTING ANY
ACCUMULATIONS OR IMPACTS AT THIS TIME. THE FOG WILL BECOME LOCALLY
DENSE LATER TONIGHT...ESPECIALLY FOR THE WESTERN PANHANDLE WHERE
VISIBILITIES MAY DROP TO 1/2 MILE OR LESS AT TIMES. ONE TO THREE
MILE VISIBILITY WILL BE POSSIBLE OVER SOUTHEAST WYOMING.
PREV DISCUSSION... /ISSUED 523 PM MST MON DEC 12 2011/
AVIATION...00Z TAF ISSUANCE...LIFR CONDITIONS PERSIST AT CHADRON.
THESE LOW CONDITIONS WILL GRADUALLY OVERSPREAD THE REMAINDER OF THE
PANHANDLE AND EXTREME SOUTHEAST WYOMING TONIGHT PER THE LATEST
HRRR MODEL OUTPUT. THE NAM SHOWS SOME MVFR TO IFR CONDITIONS
DEVELOPING ACROSS CARBON COUNTY OVERNIGHT. THE LOW CEILINGS
AND VISIBILITIES WILL LIKELY LINGER THROUGH LATE TUESDAY MORNING
BEFORE IMPROVING TO MVFR OR BETTER. LIGHT SOUTH TO SOUTHEAST
WINDS TONIGHT WILL VEER TO SOUTHWEST TUESDAY MORNING.
PREV DISCUSSION... /ISSUED 235 PM MST MON DEC 12 2011/
SHORT TERM...TONIGHT THROUGH THURSDAY...
FOR THIS FORECAST THE CURRENT UPPER LOW CURRENTLY OVER CENTRAL
CALIFORNIA WILL MOVE NORTHEAST AND ACROSS THE ROCKIES. THE FEATURE
WILL SLOWLY FILL AS IT MOVES NORTHEAST AND THE TROUGH AXIS WILL BE
EAST OF THE CWA LATE WEDNESDAY AFTERNOON OR WEDNESDAY EVENING.
DURING THAT SAME TIME...SURFACE UPSLOPE WIND FLOW WILL PERSIST OVER
MUCH OF THE CWA. AS THE PLAINS SURFACE HIGH MOVES FURTHER EAST...
THE BOUNDARY LAYER WINDS WILL TURN TO MORE SOUTHWEST TUESDAY
AFTERNOON. PRIOR TO THAT...WIDESPREAD LOW CLOUDS AND FOG WILL
SPREAD AND DEVELOP OVER MUCH OF THE CWA BY 06Z. CURRENT AND
FORECAST RAOBS INDICATE THAT THE CLOUD DEPTH WILL BE BETWEEN 1000
AND 1500 FEET WHICH SHOULD NOT BE ENOUGH FOR FLURRIES OF FREEZING
DRIZZLE. THE SOUTHWEST BOUNDARY LAYER WINDS TUESDAY AFTERNOON
SHOULD HELP DISSIPATE THE LOWER CLOUDS AND FOG OVER THE EAST PART OF
THE CWA. WITH THE SHORTWAVE TROUGH PASSAGE ON WEDNESDAY
AFTERNOON...NORTHWEST SURFACE WINDS WILL INCREASE WITH SOME GUSTS
BETWEEN 30 AND 40 MPH. THOSE WINDS WILL PERSIST OVER AREAS ALONG
AND EAST OF THE LARAMIE RANGE THROUGH THURSDAY. MOST OF ANY
PRECIPITATION WILL OCCUR OVER AND NEAR THE SNOWY AND SIERRA MADRE
RANGES THROUGH THURSDAY AND WILL BE IN THE FORM OF LIGHT SNOW OR
FLURRIES. THERE MAY BE ENOUGH LIFT AS WELL OVER THE SOUTHEAST
QUARTER OF THE CWA FOR LATER TONIGHT AND WEDNESDAY MAINLY DUE TO THE
LOCATION OF THE 300 MB JET...HOWEVER MOISTURE DEPTH WILL BE
LACKING.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
12/12Z GFS AND ECMWF SIMILAR SYNOPTICALLY AT 500 MB...THUS MODERATE
TO HIGH CONFIDENCE IN THEIR RESPECTIVE SOLUTIONS.
WEDNESDAY NIGHT/THURSDAY...OUR COUNTIES WILL BE IN BETWEEN SYSTEMS...
THUS DRY. LOOKS LIKE ENOUGH MID/HIGH CLOUDS IN ADVANCE OF SHORTWAVE
TROUGH ALOFT OVER THE GREAT BASIN STATES TO KEEP OUR HIGH
TEMPERATURES IN THE 30S.
FRIDAY...NEXT COLD FRONT PLOWS ACROSS ALONG WITH CHANCES FOR SNOW...
THOUGH SNOW COVERAGE AND INTENSITY WILL BE LIMITED AS THE ENERGY
WITH THE SHORTWAVE TROUGH ALOFT IS SPLIT AND SHEARED WITH MOST OF
THE ENERGY REMAINING SOUTH OF WYOMING.
SATURDAY...CUTOFF LOW ALOFT WILL LIE TO OUR SOUTH WITH PRECIPITATION
OVER ARIZONA AND NEW MEXICO. DRY ACROSS OUR COUNTIES WITH SURFACE
LEE TROUGHING.
SUNDAY...TROUGH ALOFT OPENS UP AND MOVES ACROSS COLORADO AND NEW
MEXICO WITH PRECIPITATION TO THE SOUTH OF WYOMING AND NEBRASKA. LACK
OF CLOUD COVER ALONG WITH 1000-500 MB THICKNESSES NEAR 5490 METERS
WILL HELP HIGH TEMPERATURES REACH THE 30S AND MID 40S.
MONDAY...NEXT COLD FRONT MOVES ACROSS OUR COUNTIES WITH HIGH
TEMPERATURES BACK IN THE 20S AND 30S. LOOKS LIKE ENOUGH LOW AND MID
LEVEL MOISTURE FOR SCATTERED COVERAGE OF SNOW ACROSS THE NORTHERN
LARAMIE...SNOWY AND SIERRA MADRE RANGES...DRY ELSEWHERE.
FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE CWA THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL BE NEAR NORMAL OVERALL AND...OUTSIDE OF
WEDNESDAY...WINDS WILL BE FAIRLY LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...WEILAND
LONG TERM...RUBIN
AVIATION/UPDATE...JAMSKI
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1104 PM CST WED DEC 14 2011
.DISCUSSION...
ISSUED 830 PM CST WED DEC 14 2011
RATHER IMPRESSIVE UPPER LEVEL WAVE AND SPEED MAX SEEN ON WATER
VAPOR LOOP THIS EVENING ACRS OKLAHOMA...WHICH IS TRACKING
NE AND BRINGING IN ANOTHER ROUND OF RAIN AND THUNDERSTORMS...
THIS TIME TO THE SOUTHERN HALF OF THE FORECAST AREA. FURTHER
NORTH AND WEST...STILL SEEING SOME PRECIP...BUT MORE LIGHT
RAIN AND DRIZZLE THAN THE STEADIER RAINS THAT OCCURRED IN THIS
AREA THRU MOST OF THE DAY. RAINFALL TOTALS RANGED FROM 2 TO 3
INCHES ROUGHLY ALONG AND NORTH OF A RUSHVILLE TO BLOOMINGTON
LINE...WITH TOTALS DROPPING OFF DRAMATICALLY TO THE SOUTH.
HIGHEST POPS WILL CONTINUE ACRS THE SOUTHEAST HALF OF THE FORECAST
AREA FOR THE REST OF THIS EVENING AND INTO THE EARLY MORNING HOURS.
THE COMBINATION OF THE CLOUD COVER AND GUSTY SOUTH WINDS WILL KEEP
TEMPS STEADY THRU THE NIGHT...AND SOME 10 TO 15 DEGREES ABOVE NORMAL
HIGH TEMPERATURES FOR THIS TIME OF YEAR! THE COLD FRONT WHICH IS
SLATED TO MOVE THRU PIA AROUND 3 OR 4 AM WAS JUST EAST OF DES MOINES
THIS EVENING...WITH SURFACE DEW POINTS IN THE MID TO UPPER 50S
STREAMING NORTH JUST AHEAD OF THE BOUNDARY. PRECIP WILL END LAST
ACRS THE FAR SOUTHEAST EITHER LATE TOMORROW MORNING OR EARLY
AFTERNOON AS THE SURFACE LOW DEEPENS OVER THE UPPER GREAT LAKES
DRAWING DOWN COLDER AIR FOR THE REST OF THE WORK WEEK. HAVE ADJUSTED
POPS OUT A BIT LATER INTO THE OVERNIGHT HOURS ACRS MAINLY OUR EAST
AND SOUTHERN AREAS...BASED ON THE BAND OF RAIN AND ISOLD THUNDERSTORMS
OCCURRING FROM EAST CENTRAL IL SOUTHWEST THRU SOUTH CENTRAL MISSOURI.
SHOULD HAVE THE UPDATED ZONES OUT BY 900 PM.
SMITH
&&
.AVIATION...
ISSUED 1100 PM CST WED DEC 14 2011
TIMING OF COLD FRONT ACROSS THE TAF SITES AND DURATION OF IFR/MVFR
CIGS THE MAIN FORECAST CHALLENGES THIS PERIOD. COLD FRONT WAS TRACKING
INTO EAST CENTRAL IOWA AND IT APPEARS IT SHOULD BE PUSHING INTO WEST
CENTRAL IL BETWEEN 08Z AND 10Z. EXTENSIVE MVFR AND IFR CIGS WERE
PRESENT ACRS THE REGION LATE THIS EVENING WITH SOME CLEARING TAKING
PLACE OVER PARTS OF NW MISSOURI...WHICH WAS BEING REPLACED BY MORE
MVFR AND IFR CIGS BEHIND THE COLD FRONT. THE STEADIER RAINS HAVE
SHIFTED OFF TO THE EAST...WITH MORE LIGHT RAIN AND DRIZZLE OCCURRING
ACRS THE AREA AND EXPECTED TO HOLD THRU MOST OF THE NIGHT. REALLY
DON`T SEE ANY SIGNIFICANT CHANGES TO THE CIGS/VSBYS FOR ANY LENGTH OF
TIME TONIGHT INTO THU MRNG. WE MAY SEE A TEMPORARY BREAK IN THE CIGS
IMMEDIATELY BEHIND THE COLD FRONT...WHICH WILL BE FOLLOWED BY AN
INCREASE IN STRATUS AND STRATOCU CLOUDS AS THE LOW LEVEL COLD ADVECTION
RAMPS UP IN THE WAKE OF LOW PRESSURE AREA WHICH SHOULD BE DEEPENING
UP ACRS THE NORTHERN GREAT LAKES TOMORROW MORNING.
STRONG CYCLONIC FLOW AND LOW LEVEL COLD ADVECTION SHOULD BRING MOST
IF NOT ALL OF THE MVFR/IFR CIGS NOW PRESENT ACRS NRN IOWA INTO OUR
AREA TOMORROW ALONG WITH GUSTY WEST TO NORTHWEST WINDS. FORECAST
SOUNDINGS CONTINUE TO SHOW A RATHER SIGNIFICANT SUBSIDENCE INVERSION
DEVELOPING TOMORROW WHICH WILL TRAP THE LOW LEVEL MOISTURE/LOW CLOUDS
IN OUR AREA THRU AT LEAST THE EARLY AFTERNOON HOURS BEFORE WE SEE A
GRADUAL DECREASE IN CLOUDS LATER IN THE DAY. SFC WINDS WILL CONTINUE
FROM A SOUTHERLY DIRECTION FOR THE NEXT FEW HOURS AND THEN VEER INTO
A SOUTHWEST DIRECTION JUST AHEAD OF THE COLD FRONT. WINDS WILL SHIFT
INTO A WEST TO NORTHWEST DIRECTION JUST AFTER FROPA WITH SPEEDS AVERAGING
FROM 15 TO 20 KTS...WITH A FEW GUSTS APPROACHING 30 KTS AT TIMES. WINDS
SHOULD GRADUALLY DIMINISH TOMORROW NIGHT AS THE STORM SYSTEM PULLS AWAY.
SMITH
&&
.PREV DISCUSSION...
ISSUED 238 PM CST WED DEC 14 2011
SPRING-LIKE STORM SYSTEM BRINGING SHOWERS AND SCATTERED
THUNDERSTORMS TO THE CENTRAL/NORTHERN CWA TODAY IN BROAD...WARM
SOUTHWEST FLOW. HEAVIEST RAINS OF 1.5-2.5 INCHES HAVE FALLEN NORTH
OF A BEARDSTOWN TO BLOOMINGTON LINE. MODERATE RAINFALL RATES AND
UNFROZEN GROUND HAVE PRODUCED LITTLE IN THE WAY OF WATER PROBLEMS.
UPPER LEVEL DYNAMICS HELPING DRIVE THIS ACTIVITY AS SFC LOW AND
FRONT ANALYZED AT 19Z ACROSS EASTERN NEB/NRN KS. EVEN WITH THICK
CLOUDS AND RAIN...EARLY AFTERNOON TEMPS WERE RUNNING 15-20 DEGREES
ABOVE NORMAL. SHORT TERM FORECAST ISSUE IS ENDING OF RAIN WITH
COLD FRONTAL PASSAGE LATE TONIGHT AND RETURN TO SEASONABLE TEMPS.
BEYOND...NEXT MAJOR SYSTEM LOOKS TO IMPACT REGION EARLY NEXT WEEK.
SHORT TERM...TONIGHT THROUGH THURSDAY
UNSEASONABLY HIGH P/W VALUES AROUND 1.25 INCHES AND STRONG FORCING
ALOFT WILL CONTINUE TO DRIVE MODERATE RAIN AND EMBEDDED
THUNDERSTORMS THIS EVENING. LATEST HIGH RES NAM AND HRRR RUNS SHOW
ROUNDS OF CONVECTION TRANSLATING EAST ACROSS THE CWA THROUGH LATE
EVENING. PLENTY OF ELEVATED INSTABILITY FOR THUNDER...AND VERY
STRONG LLJ OVERHEAD /1 KM AGL WINDS 50 KTS/ BUT DUE TO STRONG LOW
LEVEL INVERSION DO NOT EXPECT ANY OF THIS TO MAKE IT DOWN TO THE
SURFACE. MAIN BATCH OF RAIN ASSOCIATED WITH PRE-FRONTAL TROUGH
LOOKS TO PUSH INTO INDIANA AFTER MIDNIGHT...WHEN THE ACTUAL COLD
FRONT ENTERS THE NW CWA. EXPECT A LINE OF SCATTERED SHOWERS
ALONG/AHEAD OF THE FRONT...WHICH WILL EXIT THE SE CWA AROUND 15Z
THU. BRISK WEST WINDS GUSTING TO 20-25 MPH WILL MOVE IN BEHIND THE
FRONT...BRINGING IN COOLER AND DRIER AIR.
CLOUD FORECAST FOR THURSDAY IS PROBLEMATIC WITH DRY AIR ADVECTING
IN...BUT FCST SOUNDINGS SHOW A SHALLOW LAYER OF MOISTURE TRAPPED
BENEATH A SHARP SUBSIDENCE INVERSION AROUND 925 MB. THIS COMBINED
WITH CYCLONIC FLOW ALOFT AND WEAK SUN ANGLE MAKES A LOW STRATUS
DECK LOOK LIKELY TO HOLD AT LEAST INTO MID AFTERNOON. TEMPERATURES
MAY HOLD STEADY FOR A FEW HOURS IN THE MORNING...THEN SLOWLY FALL
THROUGH THE AFTERNOON WHEN STRONGER CAA KICKS IN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
QUIET AND SEASONABLE WEATHER IS ON TAP FOR THE FRIDAY INTO SUNDAY
PERIOD. ZONAL/WNW FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL
BE RESPONSIBLE FOR THE TRANQUIL CONDITIONS. AS THE HIGH SHIFTS OFF
TO THE SOUTHEAST LATE IN THE WEEKEND SOUTHERLY FLOW DEVELOPS AHEAD
OF THE NEXT SYSTEM IN THE SW.
CURRENT INDICATIONS SHOW THIS EVENT MAY BE SIMILAR TO THE STORM
THAT IS CURRENTLY IMPACTING THE AREA. THE 12Z ECMWF AND CANADIAN GEM
ARE SIMILAR IN TRACKING A STRONG LOW FROM THE TX PANHANDLE REGION
MONDAY MORNING...INTO THE LOWER GREAT LAKES BY TUESDAY EVENING.
12Z GFS IS MUCH SLOWER AND FARTHER SOUTH AND WAS NOT FOLLOWED FOR
THIS FORECAST. EVENTUAL LOW TRACK WILL DETERMINE EXACT PRECIP TYPE
AND AMOUNTS...BUT CURRENT SOLUTION WOULD POINT TO PRIMARILY
ANOTHER MODERATE RAIN EVENT FOR THE CWA FOR SUNDAY NIGHT INTO TUESDAY.
LATER MODEL RUNS WILL NEED TO BE MONITORED...AS ECMWF DIGS A
NORTHERN STREAM WAVE INTO THE MIDWEST FOR A MORE PHASED SYSTEM AND
POTENTIAL SNOW BAND ON THE NW SIDE OF THE STORM. AFTER A BRIEF
SHOT OF COLDER AIR BEHIND THIS LOW...ZONAL FLOW LOOKS TO MODERATE
TEMPS FOR MID WEEK.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
139 AM EST THU DEC 15 2011
.AVIATION/UPDATE...
HEAVIER RAIN HAD SHIFTED WELL SOUTHEAST OF FWA...BUT AREAS OF RAIN
CONTINUE TO DEVELOP AHEAD OF A COLD FRONT EXTENDING FROM NORTH
CENTRAL IL TO WEST CENTRAL IL. THIS FRONT WILL MOVE ACROSS NRN
INDIANA LATER THIS MORNING...WITH WINDS SHIFTING TO THE WEST AND
INCREASING BEHIND THE FRONT. HAVE UPDATED GRIDS FOR MAINLY MINOR
UPDATED AND TO GET RID OF EVENING WORDING. IFR CONDITIONS SHOULD
IMPROVE ONCE THE FRONT PASSES.
&&
.PREV DISCUSSION... /ISSUED 754 PM EST WED DEC 14 2011/
SHORT TERM... TONIGHT THROUGH THURSDAY NIGHT... KIWX RADAR
DEPICTING BAND OF MOD/HVY RAIN ALONG/AHEAD OF WARM FRONT LIFTING
NORTH THROUGH THE AREA THIS AFTERNOON. THIS IS IN ASSOCIATION WITH
DEVELOPING SFC LOW IN CENTRAL PLAINS. WATER VAPOR IMAGERY AND
LATEST RUC ANALYSIS SHOWING LEAD SHORT WAVE EJECTING OUT OF FOUR
CORNERS AND WILL COMBINE WITH COUPLED JET STRUCTURE FROM NORTHERN
GREAT LAKES DOWN INTO THE CENTRAL PLAINS TO DEEPEN SFC LOW AND
DRIVE IT INTO WESTERN GREAT LAKES THIS EVENING. THIS WILL PLACE
THE FCST AREA IN ENHANCED MOIST SOUTHERLY FLOW IN THE WARM SECTOR
AND SUPPORT ANOTHER ROUND OF PRECIPITATION TONIGHT. COLD FRONT
WILL MOVE THROUGH THE AREA ON THURSDAY AND BRING AN END TO RAIN BY
18Z. SIGNIFICANT DRYING BEHIND THE FRONT ALONG WITH MARGINAL DELTA
T WILL PROVIDE LITTLE SUPPORT FOR LES IN THE WAKE OF THIS SYSTEM
SO FAVOR CURRENT GRIDS IN KEEPING JUST A MENTION OF FLURRIES ATTM.
FIRST TWO PERIODS OF FCST WILL FEATURE NON-DIURNAL TEMP PATTERN AS
WARM FRONT LIFTING NORTH OF THE AREA TONIGHT WILL KEEP TEMPS
STEADY/SLOWLY RISING...THEN CAA BEHIND PASSAGE OF COLD FRONT
THURSDAY WILL SEE HIGHS REACHED IN THE MORNING FOLLOWED BY FALLING
TEMPS IN THE AFTERNOON. COOLER BUT SEASONABLE TEMPS THURSDAY NIGHT
WITH LOWS IN THE MID-UPPER 20S.
LONG TERM...
FRIDAY THROUGH WEDNESDAY
ACTIVE NORTHERN STREAM WILL INFLUENCE LOWER HEIGHTS INTO THE REGION
THIS WEEKEND WITH COLDER/DRIER AIR PUSHING INTO THE GREAT LAKES...AS
PERIPHERY DISTURBANCES ADVECT THROUGH THE FLOW. A SERIES OF THESE
WEAK INFLUENCES MAY INFLUENCE ENOUGH LIFT AND COLUMN SATURATION TO
SUPPORT LIGHT SNOW OR FLURRIES ACROSS THE NORTH...ALONG WITH A WEAK
LAKE RESPONSE. OTHERWISE...MODELS AND ENSEMBLES CONTINUE TO SUPPORT
THE EJECTION OF A SW CONUS DISTURBANCE INTO THE REGION BY EARLY NEXT
WEEK...WITH SOME RATHER SIG DISCREPANCIES AMONG DETERMINISTIC
SOLUTIONS. WILL STAY THE COURSE WITH PERSISTENCE...FAVORING THE
WARMER ECMWF AND GEM. THIS WILL ESP BE TRUE IF FLOW PHASING IS
REALIZED...WHICH IS CERTAINLY POSSIBLE GIVEN THE PATTERN. SMALL
ADJUSTMENT MADE TO THE PREVIOUS FORECAST...GENERALLY TO POPS/WX.
FRI-SUN...OVERALL DRY/SLIGHTLY DISTURBED FLOW WILL REMAIN IN THE
GREAT LAKES REGION. CONTINUED TO OPT NOT TO INCLUDE A LAKE EFFECT
SNOW SHOWER MENTION FRI-SAT FAR NW GIVEN MARGINAL SUPPORT FOR LAKE
INDUCE CONVECTION...WITH ONLY A FLURRY MENTION ATTM...SPREAD OVER
THE ENTIRE NORTH TO COVER THE POTENTIAL FOR LIGHT SNOW WITH ANY OF
THE WEAK DISTURBANCES. PROFILES INDICATE SIG DRYING IN THE SFC TO H8
LAYER WITH MARGINAL DELTA T/S PRESENT. CANNOT RULE OUT A FEW
FLURRIES OR LIGHT LAKE EFFECT SNOW SHOWERS IF COLDER PROFILES
VERIFY...COUPLED WITH A WEAK NORTHERN STREAM DISTURBANCE PROGGED
INTO THE REGION...WHICH COULD GENERATE ENOUGH INVERSION HEIGHT
UNDULATION TO SUPPORT PERHAPS A FEW SNOW SHOWERS/FLURRIES IN SHORT
FETCH WESTERLY FLOW. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN AROUND
NORMAL TO SLIGHTLY ABOVE IN THE PERIOD...WITH LAKE EFFECT CLOUDS
ACROSS NORTHERN AREAS LINGERING THROUGH SAT.
MON-WED...CHANCES FOR A DECENT STORM SYSTEM CONTINUE...AS AN ACTIVE
NORTHERN STREAM IMPULSE LIKELY INTERACTS WITH ANOTHER SW CONUS
UPPER LOW. ADVECTION TIMING/THERMAL FIELDS/AND HEIGHT FALL DEPTH
INTO THE REGION IS STILL MUCH UNCERTAIN...BUT GIVEN THE GFS/S
TENDENCY TOWARD PROGRESSIVE FLOW...LIKELY BIASING THE NAEFS
SOLUTIONS...HAVE CONTINUED TO SIDE TOWARD THE MORE RELIABLE ECMWF. A
TREND TO A DEEPER H5 SOLUTION WOULD CERTAINLY BE NEEDED...ESP IF
WAVE PHASING RESULTS...WITH COUPLED JET DYNAMICS LIKELY SHIFTING THE
SFC LOW TRACK NW OF THE FA...AS SEEN IN THE GEM. RETAINED A
RAIN/SNOW MENTION IN MOST PERIODS...MAINLY TO COVER
UNCERTAINTY...BUT IT CERTAINLY LOOKS LIKE RAIN WILL BE THE DOMINATE
WEATHER TYPE IN THE PERIOD...ESP SE HALF. CONTINUE TO EXPECT MORE
ADJUSTMENT IN THIS PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...JC
AVIATION/UPDATE...SKIPPER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1153 PM CST WED DEC 14 2011
.AVIATION...
A COLD FRONT SLOWLY MOVING THROUGH THE AREA THIS EVENING. IT IS
PRECEDED BY A NARROW BAND OF SHOWERS THAT HAS NOW MOVED THROUGH
THE FOUR TERMINAL LOCATIONS. WINDS HAVE NOW ALSO SWITCHED TO
SOUTHWEST OR WEST. THE COLD FRONT HAS LIFTED CIGS AND VSBYS TO
MVFR OR EVEN VFR AS IT HAS MOVED THROUGH EACH OF THE TERMINALS.
STRATUS TO SPREAD BACK INTO THE TERMINALS BEHIND THE COLD
FRONT...AND AT LEAST TEMPORARILY WILL DROP CIG HEIGHTS TO IFR.
THIS IS NOT EXPECTED TO PERSIST...AND SHOULD RISE TO MVFR BEFORE
MID MORNING. CLEARING OF THE STRATUS IS UNCLEAR. INDICATIONS SHOW
AFTERNOON CLEARING AND THEN A CLEAR OVERNIGHT. HOWEVER...THIS TIME
OF YEAR IT IS MORE DIFFICULT TO CLEAR THIS STRATUS AND IT MAY
LINGER OVERNIGHT TONIGHT AS WELL. ..LE..
&&
.PREV DISCUSSION... /ISSUED 319 PM CST WED DEC 14 2011/
SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB WARM FRONT FROM SOUTH DAKOTA INTO
SOUTHERN WISCONSIN. A LLJ RAN FROM THE WESTERN GREAT LAKES TO NORTH
TEXAS WITH THE STRONG CORE OF 50-55 KNOTS FROM EASTERN KANSAS INTO
NORTH TEXAS. A STRONG MOISTURE FEED RAN FROM THE GULF COAST INTO THE
WESTERN GREAT LAKES. RADAR TRENDS SHOW THE CONVECTION AND
THUNDERSTORMS HAVE SHIFTED INTO EASTERN ILLINOIS WITH PRECIPITATION
INTENSITY DECREASING ACROSS IOWA AND MISSOURI.
18Z SFC ANALYSIS HAD A WEAK LOW NEAR KLNK WITH A WARM FRONT ALONG
THE IA/MO BORDER INTO CENTRAL ILLINOIS. A COLD FRONT RAN FROM THE
LOW BACK INTO SOUTHEAST COLORADO. DEW POINTS SOUTH OF THE WARM FRONT
WERE IN THE 50S AND 60S.
SHORT TERM...TONIGHT AND THURSDAY...
THE RUC HAS BEEN DOING A REASONABLE JOB OF HANDLING THE IMMEDIATE
SHORT TERM AND THE TRENDS OF THE RUC WERE FOLLOWED FOR INPUT TONIGHT.
THE LIFT TOOL INDICATES THE THREAT OF THUNDER IS NOW OVER WITH THE
PASSAGE OF A STRONG VORT MAX. OVERALL PRECIPITATION INTENSITY WILL
NOW BE LIGHT DURING THE EVENING HOURS WITH EVERYTHING TRANSITIONING
TO MORE DRIZZLE WITH TIME. THUS DRIZZLE WITH SOME RAIN WILL BE SEEN
DURING THE EVENING HOURS ALONG WITH PATCHY FOG. AFTER MIDNIGHT...
CONDENSATION PRESSURE DEFICITS SLOWLY RISE IN THE WEST WITH THE
BETTER FORCING SHIFTING EAST OF THE MISSISSIPPI. THE RUC DOES SHOW
ANOTHER ROUND OF FORCING ARRIVING AROUND MIDNIGHT IN THE WESTERN
CWFA. THUS WILL CONTINUE THE DRIZZLE WITH OVERALL LOWER CHANCES OF
RAIN. PATCHY FOG WILL STILL BE AN ISSUE AFTER MIDNIGHT.
THE OVERALL DENSE FOG IS PATCHY IN NATURE AND GENERALLY CONFINED TO
THE HWY 20 CORRIDOR. THE MORE WIDESPREAD AND LIKELY DENSE FOG SHOULD
BE SEEN ACROSS WISCONSIN AND MINNESOTA WHERE THE SFC LOW TRACKS.
THE COLD FRONT WILL MOVE THROUGH THE CWFA AFTER MIDNIGHT. WINDS
SHOULD REMAIN UP WHICH WILL KEEP THE FOG FROM GETTING TOO DENSE AS
THE OVERALL ATMOSPHERIC COLUMN COOLS. LOW TEMPERATURES SHOULD OCCUR
BETWEEN 7 AND 9 AM THURSDAY MORNING.
THURSDAY...THERE MAY OR MAY NOT BE SOME LINGERING DRIZZLE ACROSS THE
EASTERN CWFA EARLY IN THE MORNING. CONDENSATION PRESSURE DEFICITS
CONTINUE TO RISE AND NO FORCING IS PRESENT. HOWEVER...FORECAST
SOUNDINGS DO SHOW CONSIDERABLE DRYING ABOVE THE LOW CLOUDS SO SOME
DRIZZLE MAY BE POSSIBLE. CLEARING WILL BE SLOW TO OCCUR DURING THE
MORNING. AS HIGH PRESSURE BEGINS BUILDING IN BY MID DAY A GENERAL
CLEARING OF SKIES SHOULD BE SEEN FROM WEST TO EAST DURING THE
AFTERNOON. MAX TEMPERATURES WILL OCCUR BETWEEN 7 AND 9 AM THURSDAY
MORNING WITH TEMPERATURES SLOWLY FALLING THROUGH THE DAY.
..08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...THE LONG TERM
BEGINS WITH A BRIEF COOL DOWN IN THE WAKE OF OUR CURRENT
STORM...THEN AFTER ABOUT 48 HOURS OF NORTHWEST FLOW...WE BEGIN TO
TREND TOWARD ANOTHER POTENTIAL SIGNIFICANT STORM SYSTEM FOR SUNDAY
NIGHT THROUGH TUESDAY.
MOISTURE WILL BE STARVED...BUT SOME POSSIBLE FLURRIES OR BRIEF LIGHT
SNOW COULD OCCUR SATURDAY AFTERNOON IN THE FAR NORTH AS SHEARED OUT
SHORT WAVE ARRIVES FROM THE NORTHWEST. THIS LOOKS TO MAIN PRODUCE
MID CLOUDS DURING THE AFTERNOON AND EVENING HOURS SATURDAY.
TEMPERATURES WILL BE COOL...BUT NOT COLD. WITH LOWS IN THE LOWER TO
MID 20S...AND HIGHS GENERALLY IN THE LOWER TO UPPER 30S.
SUNDAY...THERE BEGINS TO BE ANOTHER CHANGE TOWARD AN ACTIVE STORM
SYSTEM. THERE ARE MAJOR DIFFERENCES IN THE POSITION OF A NORTHWEST
FLOW WAVE THAT MAKES LANDFALL ON EITHER THE SOUTHWEST CANADIAN
COAST/BRITISH COLUMBIA...OR NORTHWESTERN CONUS. THIS SMALL
DIFFERENCE IN MODELS GREATLY INFLUENCED THE AMOUNT OF PHASING OF THE
UPPER LOW WHICH SHOULD BE CUT OFF IN THE SOUTHWEST CONUS AT THAT
TIME. THE UKMET...GEM...AND ECMWF CONTINUE TO SHOW THE NORTHWEST
FLOW WAVE HITTING THE WA/OR COASTLINE THEN DRAWING THE CUT OFF LOW
NORTHEAST SUNDAY NIGHT. THE GFS MAKES A MORE NORTHERLY ENTRY INTO
CENTRAL BRITISH COLUMBIA WITH THE NORTHWESTERN SHORT
WAVE...THUS...IT IS DELAYED BY 24 HOURS ON PHASING WITH THE LOW IN
THE SOUTHWEST...AND LESS SO AT THAT. THUS...FOR THAT REASON
ALONE...THE GFS REMAINS FAR SOUTH OF OTHER GLOBAL MODELS...AS WELL
AS SLOWER. THE CURRENT STORM OVERHEAD WAS ALSO FORECAST BY THE GFS
TO BE FARTHER SOUTH WHEN IT WAS OUT IN THIS DAY 6 PERIOD FOR SIMILAR
REASONS...AND THEREFORE WHEN COMBINED WITH THE FACT THAT THERE IS
LITTLE OR NO SNOW COVER IN THE MIDWEST AND THERE IS NO ARCTIC AIR IN
PLACE TO KEEP A SYSTEM SOUTH...I BELIEVE IN A MORE PHASED NORTHERLY
SOLUTION. THIS POTENTIAL STORM LOOKS TO HAVE ANOTHER OPEN GULF...AND
MODEST TO STRONG UPPER FORCING. THUS...SHOULD IT OCCUR...ANOTHER
ROUND OF MODERATE RAIN IS LIKELY.
SNOW MAY OCCUR ON THE BACKSIDE PENDING THE SPEED OF THE SYSTEM AND
ABILITY TO DYNAMICALLY COOL THE ATMOSPHERE. THERE IS LITTLE
CONFIDENCE IN THAT PROCESS AT THIS TIME...BUT ENOUGH TO WARRANT
INCLUDING A RAIN OR SNOW FORECAST FOR THE NORTHWEST HALF MONDAY
NIGHT. TUESDAY MAY SEE SNOW...BUT THAT WILL DEPEND GREATLY ON THIS
SYSTEM REMAINING CLOSED AT MID LEVELS. WEDNESDAY OF NEXT WEEK
APPEARS DRY AND SEASONALLY COOL.
..ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
231 AM MST THU DEC 15 2011
.SHORT TERM (TODAY-SATURDAY)...
230 AM MST THU DEC 15 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE POSITIVELY
TILTED TROUGH ACROSS THE CENTRAL US...WITH MEAN AXIS EXTENDING
FROM MINNESOTA ACROSS WESTERN KANSAS TO THE BAJA PENINSULA.
EARLY THIS MORNING...RUC H7 ANALYSIS SHOWS AXIS OF POSITIVE
FRONTOGENESIS EXTENDING ACROSS EXTREME SW PART OF CWA...WHICH
COULD ACT AS A FOCUS FOR DEVELOPMENT OF FLURRIES BEFORE 12Z. WHILE
RADAR SHOWING LIGHT RETURNS SW OF THIS AREA THERE HAVE BEEN NO
REPORTS OF FLURRIES...AND CONSIDERING DRY LAYER IN PLACE BELOW
5000-7000FT WILL LEAVE MENTION OUT OF FORECAST FOR NOW AND
CONTINUE TO MONITOR.
TODAY-SATURDAY...SHORTWAVE RIDGING DEVELOPS OVER WESTERN KANSAS
IN REPOSE TO CUTOFF LOW DEEPENING OVER THE SW US. EXPECTING DRY
CONDITIONS AND A GRADUAL WARMING TREND THROUGH THIS WEEKEND.
SEASONAL TEMPS TODAY AND FRIDAY WILL BE FOLLOWED BY MILDER TEMPS
SATURDAY WHEN AFTERNOON TEMPS AROUND 50 ARE EXPECTED. WARMEST END
OF GUIDANCE FOR SAT WOULD SUPPORT TEMPS IN THE MID 50S.
DR
.LONG TERM (SUNDAY-WEDNESDAY)...
230 AM MST THU DEC 15 2011
A CUTOFF LOW PRESSURE SYSTEM SPINNING OVER BAJA ON SUNDAY WILL
BEGIN TO MOVE INLAND ALONG THE UNITED STATES MEXICO BORDER. THE
GFS KEEPS THE LOW CENTER NEAR THE BORDER AS IT MOVES EAST OF THE
ROCKIES WHILE THE ECMWF TAKES A SLIGHTLY MORE NORTHERLY
TRACK...PUTTING THE UPPER LOW IN THE NORTHERN TEXAS PANHANDLE BY
MONDAY EVENING WHILE THE GFS HAS IT IN THE SOUTHERN PANHANDLE
REGION. THIS DIFFERENCE IN TRACK AS THE LOW MOVES EAST OF THE
ROCKIES WILL MAKE THE DIFFERENCE BETWEEN THE FORECAST AREA
RECEIVING PRECIPITATION OR KEEPING THE FORECAST DRY FOR THE
BEGINNING OF NEXT WEEK. AS THE MODEL SOLUTIONS EVOLVE FROM CUTTING
OFF THE UPPER LOW OVER THE FAR SOUTHWEST UNITED STATES TO
REINCORPORATING IT INTO THE UPPER FLOW THROUGH THE FORECAST
PERIOD...CONFIDENCE IN EITHER PARTICULAR SOLUTION ARE LOW. THE
GENERAL CONSENSUS IS TO GO WITH A SLOWER SOLUTION THAT FAVORS
DELAYING PRECIPITATION ACROSS THE FORECAST AREA UNTIL MONDAY, AND
THEN KEEPING A RAIN SNOW MIX ON MONDAY THAT TRANSITIONS TO LIGHT
SNOW MONDAY NIGHT AND POSSIBLY INTO TUESDAY MORNING AS THE LOW
CONTINUES ACROSS THE SOUTHERN PLAINS AND INTO THE MISSISSIPPI
VALLEY REGION BY LATE TUESDAY.
LOCKHART
&&
.AVIATION...
951 PM MST WED DEC 14 2011
FOR THE 06Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE
PERIOD WITH ONLY A SCATTERED MID-LEVEL CLOUD DECK OVERNIGHT. SURFACE
HIGH PRESSURE WILL CONTINUE PUSHING SOUTHEAST ACROSS THE REGION WHICH
WILL RESULT IN INITIAL NORTHWEST WINDS OVERNIGHT BECOMING LIGHT AND
VARIABLE DURING MUCH OF THE DAY THURSDAY BEFORE FINALLY SETTING UP
FROM THE SOUTH/SOUTHEAST DURING THE EVENING HOURS.
050
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
336 AM CST THU DEC 15 2011
.DISCUSSION...
WEATHER WILL SETTLE DOWN FOR A FEW DAYS AS THE CENTRAL US REMAINS IN
BETWEEN SYSTEMS. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES BROAD
UPPER-LEVEL TROUGH EXTENDING FROM THE HUDSON BAY THROUGH THE
DAKOTAS/WY/AZ...WITH SHORTWAVE AHEAD OF THE TROUGH IN CO/NM.
UPPER-LEVEL JET STREAK EXTENDED FROM THE TX PANHANDLE THROUGH
WESTERN IA. HIGHER DEWPOINTS AT 850MB WERE WELL EAST...ASSOCIATED
WITH BAND OF RAIN FROM GREAT LAKES THROUGH MO/AR/TX...BUT 850MB
SATURATION WAS EVIDENT FROM THE EASTERN DAKOTAS INTO NEB/KS. AFTER
DRY SLOT HAD INITIALLY CLEARED THE CWA...NOSE OF STRATUS DECK WAS
PUSHING SOUTH OUT OF SD AND INTO EASTERN NEB/WESTERN IA THIS
MORNING...ALONG WITH GUSTY WINDS AND EVEN A STRAY FLURRY REPORT ON
THE NOSE OF THE CLOUDS.
MAIN FORECAST CONCERN WILL BE EVOLUTION OF STRATUS TODAY...THEN
WEATHER SYSTEM THAT MAY CLIP THE AREA MONDAY/TUESDAY. RUC 900MB RH
HAS A PRETTY GOOD HANDLE ON THE CURRENT STRATUS DECK...AND HAVE
FOLLOWED IT PRETTY CLOSELY FOR CLOUDS THROUGH TODAY. RUC WOULD
INDICATE CLOUDS OVERSPREADING THE AREA BY 12Z...THEN CLEARING FROM
SOUTHWEST TO NORTHEAST FROM AROUND 15-21Z. IN OTHER WORDS...STRATUS
COULD HANG ON FOR MOST OF THE DAY...ESPECIALLY IN WESTERN IA.
CLOUDS MAY PREVENT TEMPS FROM FALLING OFF MUCH BEFORE DAWN...BUT
ALSO HINDER RECOVERY TODAY...AND HAVE STAYED ON THE COOL SIDE FOR
TODAY. SKIES SHOULD CLEAR AND WINDS SHOULD DIMINISH BY SUNSET
THOUGH...JUST IN TIME FOR TEMPS TO FALL OFF INTO THE TEENS TONIGHT.
WEAK WAVE MOVING THROUGH THE NORTHWEST FLOW WILL BRING A BRIEF SHOT
OF CLOUDS ON FRIDAY...BUT OTHERWISE WILL HAVE LITTLE IMPACT ON
SENSIBLE WEATHER. WARM AIR ADVECTION WILL PICK UP ON SATURDAY AS AN
UPPER-LEVEL LOW DIGS INTO THE SOUTHWEST AND SPINS...ALLOWING
TEMPERATURES TO MODERATE THROUGH AT LEAST SUNDAY.
UPPER LOW WILL EVENTUALLY EJECT OUT OF THE SOUTHWEST...BUT MODELS
ARE STILL STRUGGLING WITH ITS EVOLUTION ACROSS THE PLAINS.
COMPLICATING THE SCENARIO IS A NORTHERN STREAM WAVE MOVING ACROSS
THE US/CANADA BORDER THAT WILL PROVIDE A PUSH OF COLD AIR AND SET UP
A BOUNDARY ACROSS THE CENTRAL PLAINS. RESULTING SPLIT FLOW SCENARIO
MAKES THE FORECAST MONDAY AND ONWARD QUITE UNCERTAIN. DID REMOVE
ALL BUT A TINY STRIP OF CONSOLATION SLIGHT CHANCE POPS IN THE
SOUTHEAST CWA FOR SUNDAY NIGHT...AS MODEL SOLUTIONS HAVE TRENDED
TOWARD SLOWER AND FURTHER SOUTH SCENARIO FOR THE EJECTING SOUTHERN
STREAM LOW. CHANCE FOR PRECIPITATION INCREASES ON MONDAY...THOUGH
THIS IS NO SLAM DUNK EITHER AS THE 00Z ECMWF CAME IN DRY AND GFS
ALSO IS DRY. CURRENTLY...TEMPERATURE PROFILES LOOK LIKE THEY WOULD
REMAIN WARM ENOUGH FOR RAIN SHOULD ANY PRECIPITATION FALL. ANY
PRECIPITATION ON MONDAY NIGHT WOULD LIKELY CHANGE TO SNOW AS COLD
AIR FILTERS IN BEHIND THE NORTHERN STREAM WAVE...THOUGH AGAIN
CONFIDENCE IS VERY LOW. 00Z ECMWF ACTUALLY HAD THE BEST CHANCE FOR
PRECIP ON TUESDAY...WHILE GFS KEEPS PRECIP CWA DRY THROUGHOUT THE
EVENT. PRECIP TYPE ON TUESDAY WOULD BE MORE QUESTIONABLE...BUT FOR
NOW...GRIDS ARE DRY. KEPT FORECAST DRY FOR THE REST OF THE LONG
TERM FORECAST...ALONG WITH TEMPS THAT ARE NEAR TO SLIGHTLY ABOVE
CLIMATOLOGY /WHICH MAKES SENSE GIVEN THE LACK OF SNOW NOW ACROSS THE
AREA/.
MAYES
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDS HAVE RETURNED TO OFK/LNK AND WILL SOON GET TO OMA AS THE
BACK EDGE OF THE CU DECK SHIFTS EWD OF THE TAF SITES. SOME SCT SC
WILL BE POSSIBLE OVERNIGHT AT OFK AND THE DECK OVER SE SD WILL HAVE
TO BE WATCHED. GUSTY NW WINDS ARE EXPECTED AT OFK/LNK DIMINISHING
BY MID AFTN THU WITH LIGHT AND VARIABLE WINDS EXPECTED BY EVENING.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
425 AM EST THU DEC 15 2011
.SYNOPSIS...
LOW PRESSURE TRACKING ACROSS SOUTHERN CANADA WILL BRING RAINY AND
BREEZY CONDITIONS TO WESTERN NEW YORK TODAY. AN ASSOCIATED COLD
FRONT WILL SWEEP ACROSS THE REGION THIS EVENING. THIS WILL BRING
COOLER AND MORE SEASONABLE TEMPERATURES...AND POSSIBLY A RAIN OR
SNOW SHOWER TONIGHT. AFTER THIS...HIGH PRESSURE WILL RIDGE TOWARD
THE EASTERN LAKES THROUGH SATURDAY...WITH JUST A CHANCE OF A
LINGERING SNOW SHOWER.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 400 AM...RADAR SHOWS A LARGE AREA OF RAIN ACROSS
NORTHEASTERN OHIO AND NORTHWESTERN PENNSYLVANIAN...WHICH IS
TRACKING INTO WESTERN NEW YORK. THIS AREA HAS GENERALLY BEEN SHOWN
BY THE PAST COUPLE RUNS OF THE RGEM/NAM12...WITH THE HRRR ALSO
KEYING ON IT QUITE WELL. WITH MODEL AGREEMENT SUPPORTING
RADAR...THINGS LOOK FAIRLY STRAIGHTFORWARD THROUGH
MID-MORNING...WITH THIS AREA OF RAIN TO MOVE ACROSS WESTERN NEW YORK
DURING THIS TIME. IT SHOULD BRING A GENERAL QUARTER TO HALF INCH OF
RAIN...AND WHILE UPSTREAM LIGHTNING HAS DIMINISHED...WILL MAINTAIN
AN ISOLATED CHANCE OF THUNDER WITH THIS...DUE TO THE INSTABILITY
ABOVE 600 MB.
STEADY RAIN WILL MOVE EAST OF LAKE ONTARIO MID-MORNING...LINGERING
THERE WELL INTO THE AFTERNOON. FOR THE REMAINDER OF WESTERN NEW
YORK...THINGS SHOULD BE MORE SHOWERY FROM MID-MORNING ON...BOTH FROM
LINGERING SHOWERS AND WITH SHOWERS GENERATED BY THE APPROACHING COLD
FRONT.
OUTSIDE OF THE RAIN...IT WILL BE NOTABLY WARM AND BREEZY TODAY.
TEMPERATURES WILL BE ON THE WARM SIDE...WITH HIGHS RANGING FROM
AROUND 50 IN THE SOUTHERN TIER...TO THE MID 50S IN DOWNSLOPE REGIONS
NORTH OF THE THRUWAY FROM THE NY/PA LINE TO ROCHESTER. WHILE 925 MB
WINDS WILL RUN 50 TO 60 KTS THROUGH THIS MORNING...THE SSW FLOW WILL
STRUGGLE TO MIX DOWN IN THE WARM AIR ADVECTION PATTERN. THROUGH
MID-MORNING...THIS SHOULD LIMIT GUSTS TO AROUND 35 MPH...PERHAPS
HIGHER ACROSS HIGHER TERRAIN IN BOTH THE SOUTHERN TIER AND THE TUG
HILL. AS WINDS VEER MORE SW LATE MORNING INTO THIS
AFTERNOON...EXPECT BETTER MIXING ON THE NIAGARA FRONTIER AS WINDS
FUNNEL ALONG THE CHAUTAUQUA RIDGE. BY THIS TIME...WINDS ALOFT WILL
HAVE DIMINISHED...BUT STILL EXPECT GUSTS IN THE 40 TO 45 MPH RANGE
FROM LATE MORNING THROUGH MID-AFTERNOON ON THE NIAGARA
FRONTIER...INCLUDING THE BUFFALO METRO REGION.
FOR TONIGHT...THE MOST SIGNIFICANT WEATHER FEATURE WILL BE AN UPPER
LEVEL TROF WHICH WILL CROSS THE REGION OVERNIGHT...EVENTUALLY
PUSHING A REINFORCING SHOT OF COLD AIR ACROSS THE REGION. EVEN
THOUGH COOLER TEMPERATURES ALOFT WILL BE IN PLACE OVERNIGHT...850 MB
TEMPS WILL RUN -3 TO -6C AHEAD OF THE SECONDARY COLD FRONT. THIS
MODEST INSTABILITY COMBINED WITH STRONG WINDS WHICH WILL LIMIT
RESIDENCE TIME ON THE LAKES SHOULD PREVENT ANY PURE LAKE EFFECT
PRECIPITATION FROM DEVELOPING. HOWEVER...THE SHORTWAVE ITSELF IS
FAIRLY POTENT...LIKELY ENOUGH SO TO SPARK SOME SHOWERS WITH ANY
MOISTURE IT CAN GRAB FROM THE LAKES. BY LARGE...RGEM/NAM12 QPF
FIELDS LOOK TO BE OVERDONE...ESPECIALLY IN UPSLOPE REGIONS. EXPECT
THERE WILL BE SOME SHOWERS WITH THE SHORTWAVE...BUT OTHERWISE
MOISTURE IS NOT DEEP ENOUGH TO GENERATE MUCH IN THE WAY OF
PRECIPITATION.
ONLY SEE A CHANCE OF SHOWERS SOUTH OF THE THRUWAY TONIGHT...WHERE IT
IS FURTHER FROM THE SHORTWAVE. THESE SHOULD MOSTLY BE IN THE FORM OF
RAIN...BUT MAY MIX WITH SNOW IN SPOTS. EXPECT SHOWERS EAST OF LAKE
ONTARIO AFTER MIDNIGHT AS THIS SHORTWAVE CROSSES. INITIALLY IT
SHOULD BE TO WARM FOR SNOW...BUT AS AIR ALOFT COOLS WITH THE
SHORTWAVE...EXPECT RAIN SHOWERS TO MIX WITH SNOW ACROSS HIGHER
TERRAIN EAST OF LAKE ONTARIO. MIXING SHOULD LIMIT ACCUMULATION
THROUGH DAYBREAK...BUT PERHAPS A WET INCH OR SO IS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
THE END OF THE WORKWEEK AND THE FIRST HALF OF THE WEEKEND WILL
FEATURE A TREND TOWARDS COOLER...MORE SEASONABLE TEMPERATURES WITH
THE POTENTIAL FOR A COMBINATION OF SYNOPTIC SCALE AND LAKE EFFECT
SNOW.
LOW PRESSURE CENTERED NEAR LAKE SUPERIOR EARLY THIS THURSDAY MORNING
WILL BE DRIFTING ACROSS THE CANADIAN MARITIMES ON FRIDAY. A
SECONDARY COLD FRONT TRAILING WEST OF THIS LOW WILL SETTLE SOUTH
ACROSS THE CWA FRIDAY MORNING...FOLLOWED BY A NORTHWEST FLOW OF
COLDER AIR. THIS WILL RESULT IN A CHANCE FOR SOME LAKE EFFECT SNOW
DURING THE MORNING WHEN THERE WILL BE SUFFICIENT LOW LEVEL MOISTURE
AND SOMEWHAT FAVORABLE SNOW GROWTH. WILL MAINTAIN HIGHER LIKELY POPS
EAST OF LAKE ONTARIO WHERE THERE WILL BE ADDITIONAL LIFT FROM A WELL
DEFINED SHORT WAVE THAT WILL BE PUSHING THROUGH NORTHERN NEW YORK
STATE. DRIER AIR AND INCREASING LOW LEVEL SHEAR WILL CAUSE ANY
LINGERING SNOW SHOWERS TO END DURING THE AFTERNOON.
A COUPLE INCHES OF SNOW IS POSSIBLE OVER THE HIGHER ELEVATIONS EAST
OF LAKE ONTARIO ON FRIDAY...BUT GENERALLY UNDER AN INCH IS EXPECTED
EAST OF LAKE ERIE.
A MUCH COOLER DAY IS ON TAP FOR FRIDAY AS 850MB TEMPS DROP FROM -8C
SOUTH TO AROUND -10C ACROSS THE NORTH COUNTRY. CORRESPONDING SURFACE
TEMPERATURES WILL RANGE THROUGH THE 30S...WITH THE COOLEST READINGS
EXPECTED EAST OF LAKE ONTARIO. A WEAK AREA OF HIGH PRESSURE BUILDING
SOUTH FROM SOUTHERN ONTARIO WILL BRING DRY WEATHER FRIDAY NIGHT.
LOOK FOR MORE SNOW SHOWERS TO DEVELOP ACROSS WESTERN NEW YORK
SATURDAY THROUGH SATURDAY NIGHT AS SEVERAL MORE SHORT WAVES CROSS
THE LOWER GREAT LAKES. WHILE SYNOPTIC SCALE FEATURES WILL BE THE
PRIMARY MECHANISM DRIVING THE SNOW SHOWERS...SOME LAKE ENHANCEMENT
IS POSSIBLE AT THOSE TIMES WHEN THE BOUNDARY LAYER WINDS BECOME
BETTER ALIGNED. THE BIGGEST DETRIMENT FOR ORGANIZED LAKE SNOWS IS
THAT THERE MAY BE TOO MUCH SHEAR GENERATED BY THE
PASSING SHORT WAVES. RIGHT NOW IT LOOKS LIKE THE BEST POTENTIAL FOR
LAKE SNOWS MAY BE OFF LAKE ERIE SATURDAY AFTERNOON INTO PART OF
SATURDAY NIGHT WHEN THE GFS SHOWS THE WINDS LINING UP FROM THE WEST.
THE NAM SHOWS QUITE A BIT MORE SHEAR DURING THIS TIME.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ANY LAKE SNOWS THAT LINGER INTO SUNDAY MORNING SHOULD WIND DOWN
DURING THE AFTERNOON AS HIGH PRESSURE OVER THE SOUTHEAST U.S.
ADVECTS WARMER AIR ACROSS THE LOWER LAKES.
FROM SUNDAY EVENING ONWARDS...TIMING DIFFERENCES STILL EXIST BETWEEN
THE MODELS REGARDING THE TIMING OF HOW QUICKLY THE CUTOFF LOW OVER
THE DESERT SOUTHWEST EJECTS INTO THE MIDWEST. THE GFS IS SLOWER ON
BRINGING THE LOW INTO THE PLAINS THAN EITHER THE GEM OR ECMWF WHILE
MAINTAINING A STRONGER ZONAL FLOW ACROSS THE GREAT LAKES WHILE THE
LATTER MODELS ARE FASTER AND AS A RESULT AMPLIFY A SHORTWAVE RIDGE
OVER THE REGION WITH RESULTING WARMER TEMPERATURES THAN THE GFS FOR
THE BEGINNING OF THE WEEK. THIS ALSO AFFECTS THE TIMING OF A
DEVELOPING SURFACE LOW OVER THE MIDWEST. IT IS TOUGH TO TIME THE
EJECTION OF THESE CUTOFF FEATURES...SO CONFIDENCE IN ANY PARTICULAR
SOLUTION IS LOW. FOR NOW WILL MAKE JUST MINOR CHANGES TO THE GOING
FORECAST WITH CHANCE POPS RUNNING NEAR CLIMATOLOGY.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
WIDESPREAD RAIN ACROSS FAR WESTERN AREAS AT 09Z WILL SPREAD TO THE
NORTHEAST. THIS SHOULD BRING A MIX OF MVF/IFR CONDITIONS...WHICH
WILL PREVAIL FOR MUCH OF THE DAY.
THE PERIOD OF STEADIEST AND HEAVIEST RAIN WILL MOVE IN DURING THE
10Z-14Z TIME FRAME...A FEW HOURS LATER EAST OF LAKE ONTARIO. THERE
IS STILL A SMALL CHANCE OF ISOLATED CONVECTION DURING THIS TIME
FRAME...AND IT APPEARS THE BEST CHANCE WILL BE ACROSS THE SOUTHERN
TIER. GIVEN THE SPARSE COVERAGE OF THIS...WILL CONTINUE WITH JUST CB
QUALIFIER.
RAIN WILL EVENTUALLY TAPER OFF FROM WEST TO EAST THURSDAY AFTERNOON
WITH MVFR CIGS LINGERING INTO TOMORROW NIGHT. SOME LIMITED LAKE
EFFECT SNOW MAY DEVELOP EAST OF THE LAKES BUT THIS WILL BE VERY
MINOR WITH JUST LOCAL MVFR IN LIGHT SNOW SHOWERS.
LOW LEVEL WIND SHEAR WILL BE WIDESPREAD TONIGHT THROUGH THE FIRST
HALF OF THURSDAY AS A STRONG 60+ KNOT LOW LEVEL JET CROSSES THE
LOWER LAKES REGION. PILOTS SHOULD BE AWARE OF RAPID LOSS OF HEADWIND
ON FINAL APPROACH.
OUTLOOK...
FRIDAY...VFR/MVFR. A CHANCE OF RAIN OR SNOW SHOWERS.
SATURDAY...AREAS OF MVFR WITH A CHANCE OF SNOW SHOWERS.
SUNDAY...VFR.
MONDAY...AREAS OF MVFR WITH A CHANCE OF SNOW SHOWERS.
&&
.MARINE...
00Z BUFKIT SOUNDINGS FROM THE NAM/GFS...AS WELL AS AVAILABLE RGEM
DATA ALL POINT TOWARD GALE CONDITIONS DEVELOPING TONIGHT. FOR LAKE
ONTARIO...HAVE HIGH CONFIDENCE IN GALES...WHERE COOLING TEMPERATURES
SHOULD ENHANCE MIXING OF 925 MB WINDS TO 45 KTS TONIGHT. ON LAKE
ONTARIO...EXPECT WINDS TO INCREASE TO GALE LATE EVENING...WITH GUSTS
LIKELY TO REACH THE PREVAILING 925 MB WINDS OF 45 KTS.
ON LAKE ERIE...WINDS MAY NOT BE QUITE AS STRONG...BUT IN THE SW FLOW
IT LOOKS LIKE WINDS WILL COME UP CONSIDERABLY EARLIER. THROUGH EARLY
AFTERNOON...A 50 KT FLOW AT 925 MB WILL BE IN PLACE ACROSS THE
REGION. WARM AIR ALOFT WILL RESULT IN AN INVERSION WHICH SHOULD KEEP
MUCH OF THIS FROM MIXING...BUT AS THIS VEERS TO THE WSW
MID-AFTERNOON...THE CHAUTAUQUA RIDGE MAY LOCALLY ENHANCE MIXING ON
LAKE ERIE...RESULTING IN MARGINAL GALES LATE AFTERNOON INTO THIS
EVENING. AS COOLER AIR MOVES IN...CONFIDENCE IMPROVES...WITH GALES
LIKELY UNTIL THE SHORTWAVE EXITS TOWARD DAYBREAK FRIDAY.
AFTER THIS...WINDS WILL DIMINISH FRIDAY AND FRIDAY EVENING...WITH
THE HIGH LIKELY TO KEEP WINDS ON THE LIGHT SIDE FOR THIS WEEKEND.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST FRIDAY FOR
LEZ020-040-041.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST
FRIDAY FOR LOZ030.
GALE WARNING FROM 10 PM THIS EVENING TO 10 AM EST FRIDAY
FOR LOZ042>045-062>065.
SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR SLZ022-
024.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...TJP/WOOD
LONG TERM...TJP/WOOD
AVIATION...APFFEL
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
344 AM CST THU DEC 15 2011
.SHORT TERM...TODAY THROUGH SATURDAY
AN ABUNDANCE OF STRATUS CLOUDS CONTINUE TO MOVE SOUTHEAST ACROSS
THE DAKOTAS...WITH THE EXTENT OF IT PUSHING WELL NORTH BACK INTO
SOUTHERN CANADA. WESTERN EDGE OF CLOUDS ACROSS SOUTH DAKOTA LIES
ALONG THE MISSOURI RIVER. ALTHOUGH...WITH A SOUTHEAST MOVEMENT TO
THE CLOUDS AND PLENTY LEFT UPSTREAM...EXPECTING THE EASTERN CWA TO
REMAIN IN CLOUDS MOST OF THE DAY. THE WESTERN CWA WILL LIKELY SEE
A BIT MORE SUNSHINE TODAY. MOST MODELS HAVING A HARD TIME PICKING
UP ON THE CLOUD COVER BUT THE RUC13 850 RH SEEMS TO HAVE A BETTER
HANDLE ON THINGS. IT WOULD SUGGEST CLOUD COVER THROUGH THE
AFTERNOON ACROSS THE EASTERN CWA...WITH THE WESTERN CWA IN MORE
SUNSHINE...AS PREVIOUSLY STATED. HAVE ALSO BEEN SEEING SCT
FLURRIES WITH THE STRATUS CLOUDS. PLENTY OF THAT UPSTREAM AS WELL
WITH KBIS AND KMBX RADARS SHOWING FLURRIES. EVEN OBS IN SOUTHERN
CANADA SHOWING -SN FROM TIME TO TIME. HAVE THEREFORE ADDED SCT
FLURRIES TO FORECAST THROUGH 18Z AND COULD BE A SITUATION WHERE IT
MAY NEED TO BE EXTENDED FURTHER INTO THE AFTERNOON ACROSS THE
EASTERN CWA WHEREVER STRATUS CLOUDS HANG ON THE LONGEST.
AGAIN...PLENTY OF ACTIVITY NOTED WELL UPSTREAM INTO SOUTHERN
CANADA. NORTHWEST WINDS WILL REMAIN BREEZY TODAY AS THE PRESSURE
GRADIENT REMAINS FAIRLY TIGHT WITH HIGH PRESSURE BUILDING IN.
HIGHEST SPEEDS WILL BE ACROSS THE EASTERN CWA WITH A DROP OFF IN
WINDS ACROSS THE WESTERN COUNTIES BY THIS AFTERNOON.
SFC HIGH WILL SETTLE IN OVER THE AREA TONIGHT BRINGING LIGHT
WINDS. NEXT ITEM TO WATCH WILL BE THE WEAK SHORTWAVE CROSSING THE
DAKOTAS LATE TONIGHT AND FRIDAY. MODELS STILL PEGGING MOST OF
THE LIGHT SNOWFALL ACROSS ND BUT THERE HAS BEEN A SLIGHT SHIFT
FURTHER SOUTH INTO NORTHERN SD. COUPLE MODELS BRINGING LIGHT QPF
INTO THE NORTHEASTERN COUNTIES AND SREF PROBS FOR .01 SHOWING
DECENT CHANCES ACROSS THE NORTHEASTERN CWA AS WELL. HAVE THEREFORE
INCREASED POPS SLIGHTLY FOR FRIDAY.
FOCUS WILL THEN SHIFT TO THE DEGREE OF WARMTH ON SATURDAY AS MILD
PACIFIC AIR BEGINS TO STREAM ACROSS THE NORTHERN PLAINS. WARM
FRONT CROSSES THE AREA DURING THE DAY SATURDAY WITH WINDS TURNING
WESTERLY. 850 MB TEMPS RISE TO JUST ABOVE ZERO C. WITH THE WIND
SHIFT AND A DECENT AMOUNT OF SUN...WILL SEE TEMPS RISE INTO THE
30S AND 40S.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
NOT MUCH TO TALK ABOUT IN THE EXTENDED FORECAST. CONSENSUS MODELS
ARE STILL GOING WITH CONTINUED DRY CONDITIONS. INTERESTINGLY THE
GFS IS STARTING TO HINT AT THE POSSIBILITY OF SOME PRECIP AT THE
END OF THE FORECAST PERIOD ASSOCIATED WITH THE NEXT UPPER TROF
THAT DIGS INTO THE PLAINS SO WILL NEED TO KEEP AN EYE ON HOW THAT
SYSTEM DEVELOPS. FOR NOW THOUGH LEFT THE FORECAST PRECIP FREE.
WITH THE LACK OF SNOW ON THE GROUND TEMPERATURES WILL ALSO
CONTINUE THE ABOVE NORMAL TREND WITH HIGHS STAYING NEAR 30 OR EVEN
CLIMBING INTO THE 40S THROUGH THE PERIOD.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
STRATUS REMAINS ACROSS THE REGION BUT HAS LIFTED TO AOA
2KFT...WITH THE EXCEPTION OF KATY WHICH HAS BEEN DELAYED A COUPLE
OF HOURS. CIGS WILL BEGIN TO BREAK UP DURING THE DAY
THURSDAY...AND VISBY IS EXPECTED TO REMAIN VFR. WINDS OUT OF THE
NORTHWEST AT 20G35MPH TONIGHT AND INTO THE DAY THURSDAY AS WELL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1132 PM CST WED DEC 14 2011
.AVIATION...
KACT...A LINE OF SHOWERS AND THUNDERSTORMS OVER THE AIRPORT AT THE
BEGINNING OF THE TAF PERIOD IS EXPECTED TO CLEAR THE AIRPORT BY
08Z/2 AM CST. AS THE LINE CLEARS...CIGS WILL IMPROVE AND THE WINDS
WILL SHIFT TO THE NORTHWEST. HOWEVER...ADDITIONAL RAIN ACTIVITY IS
EXPECTED TO DEVELOP LATER TONIGHT AS A COLD FRONT APPROACHES. THIS
NEXT EPISODE OF RAIN ACTIVITY WILL CONTINUE INTO THE DAY ON
THURSDAY AS AN UPPER LEVEL TROUGH APPROACHES THE REGION. SHOWERS
WILL BE LIKELY FOR MUCH OF THE DAY AND INTO THE EVENING HOURS ON
THURSDAY. THERE COULD BE PERIODS OR A FEW HOURS WHERE NO RAIN
OCCURS NEAR THE AIRPORT BUT THIS TIMING IS TOO CHALLENGING TO
PINPOINT AT THIS TIME. BY LATE THURSDAY EVENING...CIGS ARE
EXPECTED TO RETURN TO MVFR CONDITIONS AROUND 015 KFT.
DFW METROPLEX TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH THE
NIGHT. WEST WINDS WILL SHIFT TO THE NORTH AS A COLD FRONT PASSES
AROUND 12Z/6 AM CST. AS AN UPPER LEVEL TROUGH APPROACHES THE
REGION TOMORROW...ADDITIONAL SHOWERS ARE EXPECTED TO DEVELOP.
THESE SHOWERS COULD DEVELOP AS EARLY AS THE LATE MORNING HOURS BUT
ARE MORE LIKELY IN THE AFTERNOON AND EVENING HOURS. BY LATE
THURSDAY EVENING...CIGS ARE EXPECTED TO RETURN TO MVFR CONDITIONS
AROUND 015 KFT.
82/JLD
&&
.UPDATE...
THE RAIN HAS ENDED FOR TONIGHT ALONG AND WEST OF A SHERMAN...FORT
WORTH...COMANCHE LINE. TO THE WEST OF THIS LINE WINDS HAVE BECOME
SOUTHWEST TO WEST. WINDS WILL COME AROUND TO THE NORTHWEST AND NORTH
OVERNIGHT INTO THURSDAY MORNING AS A COLD FRONT MOVES THROUGH THE
REGION. NO CHANGES WERE MADE TO THE TOMORROW ONWARD FORECAST...AS
AN APPROACHING SHORTWAVE THURSDAY WILL RESULT IN RAIN DEVELOPING
AREAWIDE. HAVE ADJUSTED THE REST OF THE EVENING/OVERNIGHT
POPS/WEATHER/QPF FOR ONGOING TRENDS.
58
&&
.PREV DISCUSSION... /ISSUED 331 PM CST WED DEC 14 2011/
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS NORTH
TEXAS THIS AFTERNOON AS A PACIFIC COLD FRONT MOVES EAST. THE UPPER
LEVEL SYSTEM RESPONSIBLE FOR DEEP LAYER ASCENT IS SHEARING OUT
ACROSS THE SOUTHERN PLAINS AND WILL MOVE NORTHEAST THIS EVENING
ALLOWING THE FRONTAL BOUNDARY TO SLOW DOWN AS IT MOVES EAST.
LATEST RUC SOUNDINGS AND LOCALLY DERIVED CONVECTIVE PARAMETERS
INDICATE THAT 700MB WARM NOSE HAS MOSTLY ERODED WITH ONLY WEAK
INHIBITION PRESENT IN VICINITY OF THE FRONT. ANYWHERE FROM
500-700J/KG OF INSTABILITY REMAINS PRESENT AND WILL SUPPORT
THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING INTO TONIGHT.
OVERALL SEVERE WEATHER THREAT IS LOW BUT SOME HAIL WILL REMAIN
POSSIBLE. FRONT WILL DRIFT SOUTH AND EAST LATER TONIGHT WITH
PRECIP TAPERING FROM WEST TO EAST.
ALTHOUGH SURFACE FRONT WILL BE SOUTH OF THE AREA ON THURSDAY AMPLE
MOISTURE WILL RIDE ATOP THE SHALLOW COOLER AIR. REMNANTS OF THE
UPPER LOW OVER THE SOUTHWEST IS EXPECTED TO EJECT NORTHEAST DURING
THE DAY TOMORROW. THIS SYSTEM SHOULD PROVIDE SUFFICIENT FORCING TO
LIFT MOISTURE IN THE 850-700MB LAYER. ELEVATED INSTABILITY WILL BE
WEAK ALTHOUGH IT SHOULD BE SUFFICIENT FOR SHOWERY TYPE PRECIP TO
DEVELOP EVEN THOUGH THE NEAR SURFACE LAYER WILL BE DRY. MODEL
GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION AND HAVE RAISED
POPS FOR THU/THU NIGHT ACROSS NORTH TEXAS.
FRIDAY AND SATURDAY STILL LOOK LIKE THE QUIETEST DAYS THROUGH THE
NEXT SEVERAL WITH MOST AREAS STAYING DRY. THE NEXT STRONG SYSTEM
IS EXPECTED TO MOVE OUT OF THE SOUTHWEST US BY SUNDAY. MOISTURE
WILL SURGE NORTHWARD AHEAD OF THIS UPPER LOW...WHICH IS FORECAST
TO REMAIN CLOSED AS IT MOVES ACROSS NORTH TEXAS. THIS SYSTEM
CONTINUES TO LOOK MORE POTENT AND AGAIN WE MAY SEE SOME
SIGNIFICANT RAINFALL AS IT MOVES THROUGH. WILL HAVE TO MONITOR FOR
SEVERE WEATHER POTENTIAL AS WE GET CLOSER TO THE EVENT.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 54 56 40 54 38 / 30 50 70 10 10
WACO, TX 58 58 42 53 42 / 60 60 70 20 20
PARIS, TX 55 57 39 51 37 / 90 40 70 20 10
DENTON, TX 51 54 38 51 33 / 20 40 70 10 10
MCKINNEY, TX 54 56 41 52 36 / 40 40 70 20 10
DALLAS, TX 55 58 41 54 41 / 40 50 70 20 10
TERRELL, TX 57 59 42 52 40 / 90 50 70 20 10
CORSICANA, TX 59 62 45 54 42 / 70 60 70 30 20
TEMPLE, TX 59 59 42 53 43 / 60 70 70 20 20
MINERAL WELLS, TX 48 52 37 50 35 / 10 40 60 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/58
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CST THU DEC 15 2011
.SHORT TERM...TODAY THROUGH SATURDAY
343 AM CST THU DEC 15 2011
MAIN FORECAST CONCERNS ARE ON BLUSTERY NORTHWEST WINDS TODAY/CHANCES
FOR FREEZING DRIZZLE THIS MORNING...AND CLOUD COVER/FLURRIES
THROUGH THE DAY. FOCUS THEN TURNS TO SNOW CHANCES LATE FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A COLD FRONT EXTENDING FROM THE
NORTHERN LOWER MICHIGAN SOUTHWEST INTO NORTH CENTRAL MISSOURI.
SPRINKLES CONTINUE ACROSS THE FORECAST AREA THIS MORNING AS
STRATUS AND LOW LEVEL LIFT REMAIN IN PLACE. COLDER AIR WAS
FILTERING INTO THE REGION WITH TEMPERATURES FALLING INTO THE MID
30S. LOOK FOR TEMPERATURES TO CONTINUE FALLING THIS MORNING...WITH
THE POTENTIAL FOR FREEZING DRIZZLE THROUGH LATE MORNING.
LOW LEVEL SATURATION AND LIFT MAY PRODUCE SOME LIGHT FREEZING
DRIZZLE OR SNOW THIS MORNING...THEN SOME FLURRIES THIS AFTERNOON.
OTHERWISE PLAN ON CLOUDY SKIES TODAY WITH LOW LEVEL MOISTURE
REMAINING IN PLACE. MODELS ARE HAVING A DIFFICULT TIME HANDLING
THE LOW LEVEL MOISTURE TODAY...EXCEPT FOR THE RUC. HAVE TRENDED
CLOUDS AND TEMPERATURES TOWARDS THE RUC TODAY. ANY LINGERING
FREEZING DRIZZLE IS EXPECTED TO SWITCH OVER TO FLURRIES BY THIS
AFTERNOON AS COLDER AIR ALOFT MOVES IN. MESOSCALE MODELS INDICATE
PATCHY PRECIP ACROSS SOUTHEAST MINNESOTA AND MUCH OF WESTERN
WISCONSIN INTO THE AFTERNOON HOURS. THIS SIGNAL IS OFTEN
INDICATIVE OF FLURRIES OR DRIZZLE SO WILL HAVE TO KEEP A CLOSE EYE
ON THIS THROUGH THE MORNING HOURS. FORECAST SOUNDINGS SUGGEST MUCH
OF THE LOW LEVEL LIFT WILL BE LOST BY LATE AFTERNOON ALONG WITH
DRIER LOW LEVEL AIR PUSHING IN. THIS SHOULD END ANY LINGERING
PRECIPITATION. LOOK FOR BLUSTERY NORTHWEST WINDS TODAY...WITH
SPEEDS OF 15 TO 25 MPH AND GUSTS UP TO 40 MPH POSSIBLE. IT APPEARS
THAT WINDS WILL STAY BELOW ADVISORY CRITERIA SO WILL NOT BE
HOISTING A WIND ADVISORY TODAY. LOOK FOR HIGHS TO OCCUR EARLY THIS
MORNING...WITH TEMPERATURES FALLING THROUGH THE MORNING INTO THE
AFTERNOON. PLAN ON TEMPERATURES FALLING INTO THE UPPER 20S TO
LOWER 30S BY EARLY AFTERNOON. THE MAIN CONCERN TONIGHT WILL BE
CLOUD COVER AND LOW TEMPERATURES. LOOKING AT THE STRATUS
UPSTREAM...AND THE TRAJECTORIES...WOULD EXPECT THE CLOUDS TO
LINGER THROUGH TONIGHT. HAVE ADJUSTED LOWS UPWARD SLIGHTLY TO
ACCOUNT FOR THE EXPECTED CLOUD COVER. SHOULD SEE LOWS FALL INTO
THE UPPER TEENS TO LOWER 20S.
SURFACE HIGH PRESSURE IS EXPECTED TO MOVE OVER THE UPPER MISSISSIPPI
RIVER VALLEY ON FRIDAY WITH CLOUDS DECREASING ACROSS THE AREA EARLY
IN THE DAY...THEN GRADUALLY INCREASING FROM THE NORTHWEST LATE IN
THE AFTERNOON AS ANOTHER SYSTEM MOVES IN. 15.00 MODELS INDICATE A
SHORTWAVE TROUGH MOVING FROM NORTHEAST MONTANA THROUGH THE DAKOTAS
EARLY ON FRIDAY. THE SHORTWAVE WILL MOVE INTO THE FORECAST AREA LATE
FRIDAY AFTERNOON INTO FRIDAY EVENING...WITH POTENTIAL VORTICITY
ADVECTION OF 15 PVU/S IN THE 500-300 MB LAYER...MOVING INTO THE
FORECAST AREA EARLY. ISENTROPIC LIFT WILL INCREASE ACROSS THE AREA ON
THE 275-285 K SURFACES AS THE WAVE MOVES THROUGH. FORECAST SOUNDINGS
ARE SHOWING A 5000 FT DENDRITIC GROWTH ZONE FRIDAY EVENING. SHOULD
SEE A BRIEF SHOT OF SNOW FRIDAY EVENING. GIVEN THE SHORT DURATION OF
FORCING OVER THE AREA...SNOW ACCUMULATION SHOULD BE ON THE LIGHT
SIDE...RANGING FROM A HALF INCH TO PERHAPS A FEW LOCATIONS RECEIVING
AROUND 2 INCHES. HAVE INCREASED PRECIPITATION CHANCES ACROSS MUCH OF
THE FORECAST AREA FRIDAY EVENING INTO LATE FRIDAY NIGHT. CURRENT
THINKING IS THAT THE SNOW BAND WILL SET UP FROM SOUTHEAST MINNESOTA
THROUGH CENTRAL WISCONSIN...WITH THE GREATEST ACCUMULATIONS OCCURRING
ACROSS THESE AREAS. THE SNOW SHOULD TAPER OFF AFTER MIDNIGHT AS THE
SHORTWAVE MOVES INTO EASTERN WISCONSIN. LOOK FOR LOW TEMPERATURES TO
RANGE FROM THE MID TO UPPER TEENS ACROSS SOUTHEAST MINNESOTA THROUGH
NORTH CENTRAL WISCONSIN...TO THE LOWER 20S ACROSS FAR SOUTHWEST
WISCONSIN.
NORTHWEST FLOW ALOFT IS EXPECTED TO PERSIST ACROSS THE AREA ON
SATURDAY. A SHORTWAVE TROUGH WILL MOVE ACROSS LAKE SUPERIOR AND FAR
NORTHERN WISCONSIN DURING THE DAYTIME HOURS. MODELS ARE GENERATING
SOME LIGHT SNOW WITH THIS FEATURE AS IT MOVES THROUGH. THE SNOW
SHOULD STAY NORTH OF THE FORECAST AREA BUT WILL HAVE TO KEEP A CLOSE
WATCH ON THE NEXT SET OF MODEL RUNS. A FEW FLURRIES COULD FALL
ACROSS NORTH CENTRAL WISCONSIN AS THIS WAVE MOVES THROUGH. THE MAIN
IMPACT THE WAVE WILL HAVE ON THE FORECAST AREA...IS INCREASING CLOUD
COVER. LOOK FOR HIGH TEMPERATURES ON SATURDAY TO RANGE FROM THE
UPPER 20S ACROSS NORTH CENTRAL WISCONSIN TO THE MID 30S ACROSS
NORTHEAST IOWA THROUGH FAR SOUTHWEST WISCONSIN. 250 MB JET STREAK
WILL MOVE ACROSS THE REGION SATURDAY NIGHT. A SURFACE RIDGE IS
EXPECTED TO MOVE DURING THE OVERNIGHT HOURS PROVIDING MOSTLY CLEAR
SKIES. 850 MB TEMPERATURES WILL WARM THROUGH THE NIGHT...STARTING
OUT AROUND -2C AT 00Z AND WARMING TO PLUS 2 C BY 12 SUNDAY. FORECAST
SOUNDINGS ARE SHOWING THE COLD AIR HOLDING STRONG NEAR THE SURFACE
AS WARM AIR MOVES IN ALOFT. THE SOUNDINGS ALSO SATURATE NEAR THE
SURFACE SUGGESTING SOME LOW CLOUD/FOG DEVELOPMENT. LOOK FOR LOWS TO
FALL INTO THE 20S SATURDAY NIGHT.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
343 AM CST THU DEC 15 2011
15.00 MEDIUM RANGE MODELS CONTINUE TO SHOW A SPLIT FLOW PATTERN
PERSISTING ACROSS THE CONUS INTO THE MIDDLE OF NEXT WEEK. A COLD
FRONT IS EXPECTED TO SAG SOUTH ACROSS THE FORECAST AREA ON LATE
SUNDAY INTO MONDAY. THIS SYSTEM MAY BRING SOME LIGHT SNOW TO THE
AREA BUT MOISTURE WILL BE LACKING...SO ANY SNOWFALL AMOUNTS WOULD
LIKELY BE MINIMAL. THE GFS AND NAM TAKE AN UPPER LOW OVER THE
SOUTHWEST CONUS...EAST INTO THE SOUTHERN PLAINS LATE MONDAY INTO
TUESDAY. THE MODELS THEN TAKE THE LOW ACROSS THE MID MISSISSIPPI
RIVER VALLEY LATE TUESDAY INTO WEDNESDAY. MUCH OF THE PRECIPITATION
LOOKS TO STAY WELL SOUTH OF THE AREA. A MAJORITY OF THE GFS ENSEMBLE
MEMBERS ARE ALSO IN FAVOR OF THE SOUTHERN TRACK. THE GEM OFFERS A
DIFFERENT SOLUTION...TAKING THE LOW INTO THE CENTRAL PLAINS LATE
MONDAY AND LIFTING IT ACROSS SOUTHERN IOWA INTO SOUTHEAST WISCONSIN ON
TUESDAY. WILL CONTINUE A MODEL CONSENSUS BLEND DURING THIS
TIMEFRAME...KEEPING PRECIPITATION CHANCES MAINLY ALONG AND SOUTH OF
THE I-90 CORRIDOR LATE MONDAY NIGHT INTO TUESDAY. PLAN ON HIGHS
GENERALLY IN THE 30S MONDAY THROUGH WEDNESDAY...WITH LOWS IN THE 20S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1130 PM CST WED DEC 14 2011
CEILINGS AND WINDS ARE THE MAIN AVIATION CONCERNS THROUGH THURSDAY
EVENING. NORTHWEST WINDS ARE BEGINNING TO INCREASE IN THE WAKE OF
LOW PRESSURE LIFTING THROUGH THE GREEN BAY AREA. THESE WINDS ARE
HELPING TO DISSIPATE THE FOG...WITH VISIBILITIES NOW VFR AT KRST
AND IFR AT KLSE. ANTICIPATING THE IFR VISIBILITIES AT KLSE TO BE
SHORT LIVED...CLIMBING TO VFR BY 09Z. CEILINGS...ON THE OTHER
HAND...ARE NEARLY REVERSED AT THE TAF SITES WITH LIFR CONDITIONS
AT KRST AND MVFR CONDITIONS AT KLSE. WITH PLENTY OF LOW LEVEL
MOISTURE AROUND AND TEMPERATURES GRADUALLY FALLING DUE TO THE
NORTHWEST WINDS BRINGING IN COOLER AIR...THE RISE IN CEILINGS
SHOULD BE SLOW TO OCCUR. THEREFORE...AT KLSE HAVE MAINTAINED AN
MVFR CEILINGS THROUGH THURSDAY EVENING. AT KRST...ANTICIPATING
IFR/LIFR CEILINGS TO PERSIST THROUGH THURSDAY MORNING...THEN CLIMB
TO MVFR THANKS TO DAYTIME HEATING AROUND NOON. A STEADY NORTHWEST
WIND SHOULD PREVENT THE CEILINGS FROM FALLING BACK DOWN THURSDAY
NIGHT...DESPITE NIGHTTIME COOLING.
REGARDING WINDS...A TIGHTENING PRESSURE GRADIENT BEHIND THE
DEPARTING SURFACE LOW SHOULD GET KRST GUSTING OUT OF THE NORTHWEST
TO 25 KT BY 09Z AND AT KLSE BY 13Z. FURTHER INCREASES IN THE
GUSTS ARE POSSIBLE AT KRST TO 30KT AND POSSIBLY SLIGHTLY HIGHER
DURING THE DAYTIME HOURS...DUE TO DAYTIME MIXING. GUSTS AND WIND
SPEEDS SHOULD DIMINISH SOME DURING THE EVENING AS THE PRESSURE
GRADIENT BEGINS TO RELAX AND TEMPERATURES COOL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 AM CST THU DEC 15 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 PM CST WED DEC 14 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY
1130 PM CST WED DEC 14 2011
QUICK 1130 PM UPDATE...HAVE CANCELLED THE DENSE FOG ADVISORY WITH
VISIBILITIES ACROSS MUCH OF THE AREA NOW ABOVE 1/4SM. NOTE THAT
RIDGE TOPS COULD STILL SEE SOME DENSE FOG UNTIL 1 AM OR
SO...BEFORE INCREASING WEST TO NORTHWEST WINDS HELP DISSIPATE
THAT FOG TOO.
01Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TORUGH OVER MINNESOTA WITH A SHORTWAVE EVIDENT CROSSING SOUTHEAST
MINNESOTA. DPVA AHEAD OF THIS SHORTWAVE HELPING TO PRODUCE SHOWERS
MOSTLY ALONG AND NORTH OF I-90. ELSEWHERE...AREAS OF DRIZZLE
EXISTS DUE TO A PERSISTENT WEAK WARM ADVECTION AHEAD OF LOW
PRESSURE LIFTING NORTHEAST...LOCATED NEAR WATERLOO IOWA AS OF 01Z.
REGARDING THE FOG...DENSE FOG THAT DEVELOPED DURING THE AFTERNOON
DOES SEEM TO BE DISSIPATING...DUE TO EITHER RAIN MOVING ACROSS OR
WINDS TURNING NORTHWEST IN THE WAKE OF THE LOW.
SHOWERS SHOULD CONTINUE TO LIFT TO THE NORTHEAST DURING THE REST
OF THE EVENING...WITH DRIZZLE SLOWLY ENDING THROUGH THE NIGHT AS
THE LOW PULLS AWAY AND LIFT DIMINISHES. HAVE REDUCED PRECIPITATION
CHANCES FOR PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN
THIS EVENING...DUE TO MAINLY AREAS OF DRIZZLE THAT ARE NOT
PRODUCING A WIDESPREAD 0.01 OF AN INCH OF RAINFALL. ALSO...
DECREASED PRECIPITATION CHANCES AFTER MIDNIGHT WITH THE
DIMINISHING LIFT. STILL MAINTAINED SOME CHANCE...THOUGH...GIVEN
HRRR RUNS PERSISTENT SHOWING OF SOME DRIZZLE COMING IN AFTER
MIDNIGHT. THINKING IS THE HRRR MIGHT BE USING TURBULENCE BETWEEN
THE MOIST LOW LEVELS AND DRYING COMING IN ALOFT SEEN ON WATER
VAPOR AND ON THE 00Z OAX/ABR SOUNDINGS. AS FAR AS THE FOG
SITUATION GOES...WITH RECENT TRENDS OF VISIBILITIES CLIMBING...
MIGHT BE ABLE TO START CANCELLING SOME OF THE DENSE FOG ADVISORIES
EARLY. CERTAINLY MORE CONFIDENT OF THE DENSE FOG DISSIPATING ONCE
WINDS TURN WESTERLY...AS NOTED BY VISIBILITIES AT OR ABOVE 1 MILE
ALONG/WEST OF I-35 IN SOUTHERN MINNESOTA/NORTHERN IOWA.
REGARDING PRECIPITATION TYPE TONIGHT...DID REMOVE ANY MENTION OF
SNOW SINCE MODEL SOUNDINGS AS WELL AS RAOBS SUGGEST NO ICE
PRODUCTION. ALSO...LIMITED SOME OF THE FREEZING DRIZZLE
DEVELOPMENT...SHOULD IT OCCUR AT ALL...TO LATE IN THE NIGHT AS IT
MAY TAKE AWHILE FOR TEMPERATURES TO FALL GIVEN THE WIDESPREAD
ABOVE FREEZING TEMPERATURES OFF TO THE NORTHWEST.
FOR THURSDAY AND THURSDAY NIGHT...CONCERN IS GROWING THAT WE MAY
BE DEALING WITH MORE STRATUS THAN IS CURRENTLY IN THE FORECAST.
CURRENT SATELLITE IMAGERY SHOWERS STRATUS COVERING ALL OF NORTH
DAKOTA INTO NORTHEAST SOUTH DAKOTA AND EASTWARD INTO OUR FORECAST
AREA. THE 18Z NAM/GFS POORLY FORECAST THE 00Z BIS SOUNDING...WITH
900MB TEMPERATURES 4C TOO WARM...SO THE MODELS MAY NOT BE HANDLING
THE STRATUS WELL. THINKING THAT THE STRATUS MAY END UP LINGERING
RIGHT THROUGH THURSDAY NIGHT...WAITING FOR THE SURFACE RIDGE AXIS
TO PASS ON FRIDAY BEFORE IT CAN CLEAR. THIS WOULD MAKE SENSE GIVEN
HOW MUCH MOISTURE WE HAVE RECEIVED...TRYING TO PUSH COLDER AIR
INTO THE MORE MOIST AIRMASS...AND SUBSIDENCE ALOFT TRAPPING THE
LOW LEVEL MOISTURE. WITH MORE CLOUDS...TEMPERATURES THURSDAY
NIGHT COULD END UP TOO COLD. WILL PASS ON THE STRATUS ISSUE FOR THE
NEXT FULL FORECAST. FOR NOW...HAVE ONLY INCREASED CLOUD COVER SOME
ON THURSDAY INTO THURSDAY EVENING.
.LONG TERM...SATURDAY THROUGH WEDNESDAY
305 PM CST WED DEC 14 2011
YET ANOTHER SHORT WAVE TROUGH ZIPS THROUGH THE REGION IN NORTHWEST
FLOW ON SATURDAY. ONCE AGAIN...THERE IS A CHANCE FOR A BRIEF PERIOD
OF LIGHT SNOW ALONG THE BAROCLINIC ZONE RUNNING FROM NORTHWEST
THROUGH SOUTHEAST ACROSS THE REGION.
BEYOND THIS...THE ATTENTION TURNS TO A POTENT STORM SYSTEM WHICH
WILL TAKE SHAPE OVER THE DESERT SOUTHWEST OVER THE WEEKEND...AND
WILL MOVE INTO OUR AREA BY MONDAY. THE COMPUTER MODEL SIMULATIONS
CONTINUE TO STRUGGLE AND ARE AT ODDS WITH EACH OTHER AS TO HOW THIS
WILL EVOLVE. ONE SET OF SOLUTIONS SHOW A SLOW-MOVING SOUTHERN STREAM
CLOSED SYSTEM...KEEPING THE BULK OF ANY PRECIPITATION SOUTH OF OUR
AREA. BUT OTHER SOLUTIONS SUGGEST SOME PHASING WITH THE NORTHERN
STREAM...WITH A FASTER MOVEMENT AND STRONGER SYSTEM MOVING RIGHT
THROUGH THE HEART OF THE NATION. WHILE CONFIDENCE REMAINS SOMEWHAT
LOW ON WHAT WILL EVENTUALLY HAPPEN...THERE IS ENOUGH OF A HINT IN THE
VARIOUS SOLUTIONS THAT POINT TO THE LATTER OPTION. POPS ARE STILL
SOMEWHAT LOW...BUT WE SHOULD BEGIN TO HAVE A BETTER IDEA ON THIS
SYSTEM IN THE COMING DAYS.
&&
.AVIATION...THROUGH 06Z FRIDAY
1130 PM CST WED DEC 14 2011
CEILINGS AND WINDS ARE THE MAIN AVIATION CONCERNS THROUGH THURSDAY
EVENING. NORTHWEST WINDS ARE BEGINNING TO INCREASE IN THE WAKE OF
LOW PRESSURE LIFTING THROUGH THE GREEN BAY AREA. THESE WINDS ARE
HELPING TO DISSIPATE THE FOG...WITH VISIBILITIES NOW VFR AT KRST
AND IFR AT KLSE. ANTICIPATING THE IFR VISIBILITIES AT KLSE TO BE
SHORT LIVED...CLIMBING TO VFR BY 09Z. CEILINGS...ON THE OTHER
HAND...ARE NEARLY REVERSED AT THE TAF SITES WITH LIFR CONDITIONS
AT KRST AND MVFR CONDITIONS AT KLSE. WITH PLENTY OF LOW LEVEL
MOISTURE AROUND AND TEMPERATURES GRADUALLY FALLING DUE TO THE
NORTHWEST WINDS BRINGING IN COOLER AIR...THE RISE IN CEILINGS
SHOULD BE SLOW TO OCCUR. THEREFORE...AT KLSE HAVE MAINTAINED AN
MVFR CEILINGS THROUGH THURSDAY EVENING. AT KRST...ANTICIPATING
IFR/LIFR CEILINGS TO PERSIST THROUGH THURSDAY MORNING...THEN CLIMB
TO MVFR THANKS TO DAYTIME HEATING AROUND NOON. A STEADY NORTHWEST
WIND SHOULD PREVENT THE CEILINGS FROM FALLING BACK DOWN THURSDAY
NIGHT...DESPITE NIGHTTIME COOLING.
REGARDING WINDS...A TIGHTENING PRESSURE GRADIENT BEHIND THE
DEPARTING SURFACE LOW SHOULD GET KRST GUSTING OUT OF THE NORTHWEST
TO 25 KT BY 09Z AND AT KLSE BY 13Z. FURTHER INCREASES IN THE
GUSTS ARE POSSIBLE AT KRST TO 30KT AND POSSIBLY SLIGHTLY HIGHER
DURING THE DAYTIME HOURS...DUE TO DAYTIME MIXING. GUSTS AND WIND
SPEEDS SHOULD DIMINISH SOME DURING THE EVENING AS THE PRESSURE
GRADIENT BEGINS TO RELAX AND TEMPERATURES COOL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1130 PM CST WED DEC 14 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....MW
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
520 AM CST THU DEC 15 2011
UPDATED FOR 12Z TAF DISCUSSION BELOW...
.DISCUSSION...
STILL PLENTY OF WEATHER GOING ON. COLD ADVECTION TAKING SOME TIME
GETTING INTO EASTERN MN AND WESTERN WISCONSIN WITH THE FREEZING
LEVEL STILL IN THE 1500-2000 RANGE BUT DROPPING. WILL STILL NEED TO
KEEP THE POSSIBILITY OF DRIZZLE IN WI AND FREEZING DRIZZLE A
LITTLE FARTHER WEST. THE WAVE BRINGING IN THE COLDER AIR IS OVER
WESTERN LAKE SUPERIOR BUT A STRONGER WAVE DROPPING SOUTHEAST
TOWARD LAKE OF THE WOODS. THIS WILL BRING SCATTERED SNOW SHOWERS
TO MAINLY THE EASTERN PARTS OF OF THE CWA INTO THE AFTERNOON...BUT
SOME FLURRIES FOR WESTERN AREA AS WELL THIS MORNING. OF COURSE
LOTS OF CLOUD COVER UPSTREAM IN THE COLD ADVECTION PATTERN AND
THE RUC AND THE LOCAL 4KM MODEL HAVE A BETTER HANDLE ON KEEPING
CLOUDS IN MOST OF THE DAY. SINKING BEHIND THE STRONGER WAVE
ENTERING NORTHERN MN MAY PUNCH SOME HOLES IN THE CLOUD DECK OVER
EASTERN ND AND WESTERN MN LATE AFTERNOON BUT STILL MOSTLY CLOUDY
OVERALL. TEMPS WILL BE FALLING OVER EASTERN AREAS THIS MORNING
AND THEN STEADY OR JUST UP A FEW DEGREES IN THE WEST TODAY.
SEEM TO BE DECENT CONTINUITY WITH THE CLIPPER TYPE SYSTEM IN THE
NORTHERN BRANCH FOR FRIDAY. THE GFS AND NAM SIMILAR WITH SOME
DECENT LIFT IN THE -15C AREA AS THE WAVE MOVES INTO THE AREA. THE
SREF HAS BEEN TRENDING HIGHER IN DEPICTING A DENDRITIC GROWTH
ZONES AS WELL. WILL RAISE POPS MORE INTO THE CHANCE CATEGORY
ACROSS A NW TO SE CORRIDOR THROUGH THE CWA.
THE MILDER TREND IS STILL ON TRACK FOR THE WEEKEND BUT A BIT
DELAYED FOR SATURDAY. MORE OF A SOUTHWEST FLOW SETTING UP FOR
SUNDAY. THE SUNDAY TIME FRAME IS ALSO SIMILAR TO THE TIMING OF THE
THE MAX 850 MB TEMP ANOMALY SHOWN BY THE GEFS. IT IS AMAZING THAT
THE NAEFS FORECAST HAS BEEN SHOWING ABOVE NORMAL TEMPERATURES FOR
WELL OVER A MONTH ACROSS CANADA..THE UPPER MIDWEST...AND GREAT
LAKES...AND CONTINUES WITH THIS TREND WITH THE LATEST RUN OUT TO
DEC 28.
MOST OF THE PRECIP ACTION LOOKS TO BE MAINLY SOUTH OF US IN THE
SPLIT FLOW INTO THE EARLY PART OF THE WEEK..BUT STILL SOMETHING TO
WATCH.
&&
.AVIATION.../12Z TAF ISSUANCE/
MVFR/IFR CONDITIONS WILL CONTINUE THROUGH MIDDAY TODAY UNDER
MODERATE COLD AIR ADVECTION. A NORTHWESTERLY FETCH OF COLD AIR WILL
CONTINUE TO BRING WAVES OF LOW CLOUDS OVER MUCH OF THE AREA INTO
EARLY PART OF THE EVENING. AS DRIER AIR BEGIN TO FILTER OVER THE
AREA FROM NORTHWEST TO SOUTHEAST...CLOUDS SHOULD BEGIN TO ERODE AND
THIN OUT ACROSS THE AREA. SCATTERED SNOW FLURRIES WILL LINGER INTO
THE AFTERNOON. NORTHWEST WINDS 15 TO 25 KNOTS...WITH HIGHER GUSTS
AT TIMES THEN DIMINISHING TO UNDER 10 KNOTS OVERNIGHT TONIGHT. VFR
WEATHER CONDITIONS EXPECTED TONIGHT AS A HIGH PRESSURE RIDGE BUILDS
OVER THE AREA.
KMSP...MVFR WITH PATCHY IFR CONDITIONS WILL PREVAIL THROUGH LATE
AFTERNOON TODAY. CONDITIONS WILL IMPROVE TO SCATTERED CLOUDS AT OR
ABOVE 3500 FEET AGL THIS EVENING. NORTHWEST WINDS 15-25 KNOTS.
AFTER 800 PM...NORTHWEST AROUND 10 KNOTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
409 AM CST THU DEC 15 2011
.DISCUSSION...
STILL PLENTY OF WEATHER GOING ON. COLD ADVECTION TAKING SOME TIME
GETTING INTO EASTERN MN AND WESTERN WISCONSIN WITH THE FREEZING
LEVEL STILL IN THE 1500-2000 RANGE BUT DROPPING. WILL STILL NEED TO
KEEP THE POSSIBILITY OF DRIZZLE IN WI AND FREEZING DRIZZLE A
LITTLE FARTHER WEST. THE WAVE BRINGING IN THE COLDER AIR IS OVER
WESTERN LAKE SUPERIOR BUT A STRONGER WAVE DROPPING SOUTHEAST
TOWARD LAKE OF THE WOODS. THIS WILL BRING SCATTERED SNOW SHOWERS
TO MAINLY THE EASTERN PARTS OF OF THE CWA INTO THE AFTERNOON...BUT
SOME FLURRIES FOR WESTERN AREA AS WELL THIS MORNING. OF COURSE
LOTS OF CLOUD COVER UPSTREAM IN THE COLD ADVECTION PATTERN AND
THE RUC AND THE LOCAL 4KM MODEL HAVE A BETTER HANDLE ON KEEPING
CLOUDS IN MOST OF THE DAY. SINKING BEHIND THE STRONGER WAVE
ENTERING NORTHERN MN MAY PUNCH SOME HOLES IN THE CLOUD DECK OVER
EASTERN ND AND WESTERN MN LATE AFTERNOON BUT STILL MOSTLY CLOUDY
OVERALL. TEMPS WILL BE FALLING OVER EASTERN AREAS THIS MORNING
AND THEN STEADY OR JUST UP A FEW DEGREES IN THE WEST TODAY.
SEEM TO BE DECENT CONTINUITY WITH THE CLIPPER TYPE SYSTEM IN THE
NORTHERN BRANCH FOR FRIDAY. THE GFS AND NAM SIMILAR WITH SOME
DECENT LIFT IN THE -15C AREA AS THE WAVE MOVES INTO THE AREA. THE
SREF HAS BEEN TRENDING HIGHER IN DEPICTING A DENDRITIC GROWTH
ZONES AS WELL. WILL RAISE POPS MORE INTO THE CHANCE CATEGORY
ACROSS A NW TO SE CORRIDOR THROUGH THE CWA.
THE MILDER TREND IS STILL ON TRACK FOR THE WEEKEND BUT A BIT
DELAYED FOR SATURDAY. MORE OF A SOUTHWEST FLOW SETTING UP FOR
SUNDAY. THE SUNDAY TIME FRAME IS ALSO SIMILAR TO THE TIMING OF THE
THE MAX 850 MB TEMP ANOMALY SHOWN BY THE GEFS. IT IS AMAZING THAT
THE NAEFS FORECAST HAS BEEN SHOWING ABOVE NORMAL TEMPERATURES FOR
WELL OVER A MONTH ACROSS CANADA..THE UPPER MIDWEST...AND GREAT
LAKES...AND CONTINUES WITH THIS TREND WITH THE LATEST RUN OUT TO
DEC 28.
MOST OF THE PRECIP ACTION LOOKS TO BE MAINLY SOUTH OF US IN THE
SPLIT FLOW INTO THE EARLY PART OF THE WEEK..BUT STILL SOMETHING TO
WATCH.
&&
.AVIATION.../06Z TAF ISSUANCE/
FORCING WITH UPPER TROUGH NOW EXITING TO THE EAST. LEFTOVER
IFR/LIFR CONDITIONS WITH AREAS OF DRIZZLE/LIGHT RAIN REMAIN. COLDER
AIR IS MOVING INTO WESTERN AREAS AND THIS TREND WILL CONTINUE THE
REMAINDER OF THE NIGHT. SOME FLURRIES POSSIBLE OVER THE WEST...AND
MOVING EAST DURING THE REMAINDER OF THE NIGHT. PATCHY -FZDZ POSSIBLE
AS WELL...BUT WILL LIKELY REMAIN SPOTTY AND NOT LAST VERY LONG.
CLOUDS TO GRADUALLY LIFT TO MVFR THU MORNING AND BREAK OUT FROM WEST
TO EAST ACROSS MN PORTION OF THE AREA. LATEST SREF AND MODEL
GUIDANCE SUGGEST THIS TREND AS WELL. PREVIOUS FORECAST PRETTY GOOD
OVERALL...SCATTERING OUT OVER ALL THE TAF SITES THROUGH 03Z FRI.
INCREASING NORTHWEST WIND...GUSTS TO NEAR 30 KNOTS OVER THE WESTERN
AREAS...NOT QUITE AS STRONG EAST AS SURFACE LOW LIFTS NORTHEAST.
EXPECT WIND TO DIMINISH DURING WED EVENING.
KMSP...LIFR CONDITIONS FOR A FEW HOURS YET WITH PATCHY DRIZZLE
AROUND THE AREA. MAY EVEN SEE A STRAY SNOWFLAKE LATE OR PATCHY
FREEZING DRIZZLE IF TEMPERATURES COOL DOWN QUICK ENOUGH. WILL
MENTION THE -DZ FOR A FEW HOURS AND THEN CONTINUE TREND OF LIFTING
CEILING TO MVFR THROUGH 14Z. SHOULD SEE CLOUDS SCATTER OUT THROUGH
LATE AFTERNOON. NORTHWEST WINDS WILL INCREASE AND REMAIN GUSTY
THROUGH THE DAY...TAPERING OFF THROUGH SUNSET.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/DWE
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
542 AM CST THU DEC 15 2011
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
LOW CLOUDS MAINLY BETWEEN 1500-3000 FEET ABOVE GROUND LEVEL MOVED
DOWN ACROSS EASTERN NEBRASKA DURING THE EARLY MORNING HOURS WITH
GUSTY NORTHWEST WINDS. AS HIGH PRESSURE TO THE WEST BUILDS EASTWARD
INTO THE AREA...CLOUDS WILL CLEAR OUT THIS MORNING WITH VFR
CONDITIONS THE REST OF THE DAY. WINDS WILL ALSO BE ON THE DECREASE
AS THE HIGH BUILDS EAST...ESPECIALLY BY MID TO LATE AFTERNOON. DID
NOT MENTION ANY FOG FOR TONIGHT...BUT WITH CLEAR SKIES AND LIGHT
WINDS...BUT IT IS POSSIBLE. LATER SHIFTS WILL NEED TO EVALUATE THAT.
MILLER
&&
.PREV DISCUSSION... /ISSUED 336 AM CST THU DEC 15 2011/
DISCUSSION...
WEATHER WILL SETTLE DOWN FOR A FEW DAYS AS THE CENTRAL US REMAINS IN
BETWEEN SYSTEMS. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES BROAD
UPPER-LEVEL TROUGH EXTENDING FROM THE HUDSON BAY THROUGH THE
DAKOTAS/WY/AZ...WITH SHORTWAVE AHEAD OF THE TROUGH IN CO/NM.
UPPER-LEVEL JET STREAK EXTENDED FROM THE TX PANHANDLE THROUGH
WESTERN IA. HIGHER DEWPOINTS AT 850MB WERE WELL EAST...ASSOCIATED
WITH BAND OF RAIN FROM GREAT LAKES THROUGH MO/AR/TX...BUT 850MB
SATURATION WAS EVIDENT FROM THE EASTERN DAKOTAS INTO NEB/KS. AFTER
DRY SLOT HAD INITIALLY CLEARED THE CWA...NOSE OF STRATUS DECK WAS
PUSHING SOUTH OUT OF SD AND INTO EASTERN NEB/WESTERN IA THIS
MORNING...ALONG WITH GUSTY WINDS AND EVEN A STRAY FLURRY REPORT ON
THE NOSE OF THE CLOUDS.
MAIN FORECAST CONCERN WILL BE EVOLUTION OF STRATUS TODAY...THEN
WEATHER SYSTEM THAT MAY CLIP THE AREA MONDAY/TUESDAY. RUC 900MB RH
HAS A PRETTY GOOD HANDLE ON THE CURRENT STRATUS DECK...AND HAVE
FOLLOWED IT PRETTY CLOSELY FOR CLOUDS THROUGH TODAY. RUC WOULD
INDICATE CLOUDS OVERSPREADING THE AREA BY 12Z...THEN CLEARING FROM
SOUTHWEST TO NORTHEAST FROM AROUND 15-21Z. IN OTHER WORDS...STRATUS
COULD HANG ON FOR MOST OF THE DAY...ESPECIALLY IN WESTERN IA.
CLOUDS MAY PREVENT TEMPS FROM FALLING OFF MUCH BEFORE DAWN...BUT
ALSO HINDER RECOVERY TODAY...AND HAVE STAYED ON THE COOL SIDE FOR
TODAY. SKIES SHOULD CLEAR AND WINDS SHOULD DIMINISH BY SUNSET
THOUGH...JUST IN TIME FOR TEMPS TO FALL OFF INTO THE TEENS TONIGHT.
WEAK WAVE MOVING THROUGH THE NORTHWEST FLOW WILL BRING A BRIEF SHOT
OF CLOUDS ON FRIDAY...BUT OTHERWISE WILL HAVE LITTLE IMPACT ON
SENSIBLE WEATHER. WARM AIR ADVECTION WILL PICK UP ON SATURDAY AS AN
UPPER-LEVEL LOW DIGS INTO THE SOUTHWEST AND SPINS...ALLOWING
TEMPERATURES TO MODERATE THROUGH AT LEAST SUNDAY.
UPPER LOW WILL EVENTUALLY EJECT OUT OF THE SOUTHWEST...BUT MODELS
ARE STILL STRUGGLING WITH ITS EVOLUTION ACROSS THE PLAINS.
COMPLICATING THE SCENARIO IS A NORTHERN STREAM WAVE MOVING ACROSS
THE US/CANADA BORDER THAT WILL PROVIDE A PUSH OF COLD AIR AND SET UP
A BOUNDARY ACROSS THE CENTRAL PLAINS. RESULTING SPLIT FLOW SCENARIO
MAKES THE FORECAST MONDAY AND ONWARD QUITE UNCERTAIN. DID REMOVE
ALL BUT A TINY STRIP OF CONSOLATION SLIGHT CHANCE POPS IN THE
SOUTHEAST CWA FOR SUNDAY NIGHT...AS MODEL SOLUTIONS HAVE TRENDED
TOWARD SLOWER AND FURTHER SOUTH SCENARIO FOR THE EJECTING SOUTHERN
STREAM LOW. CHANCE FOR PRECIPITATION INCREASES ON MONDAY...THOUGH
THIS IS NO SLAM DUNK EITHER AS THE 00Z ECMWF CAME IN DRY AND GFS
ALSO IS DRY. CURRENTLY...TEMPERATURE PROFILES LOOK LIKE THEY WOULD
REMAIN WARM ENOUGH FOR RAIN SHOULD ANY PRECIPITATION FALL. ANY
PRECIPITATION ON MONDAY NIGHT WOULD LIKELY CHANGE TO SNOW AS COLD
AIR FILTERS IN BEHIND THE NORTHERN STREAM WAVE...THOUGH AGAIN
CONFIDENCE IS VERY LOW. 00Z ECMWF ACTUALLY HAD THE BEST CHANCE FOR
PRECIP ON TUESDAY...WHILE GFS KEEPS PRECIP CWA DRY THROUGHOUT THE
EVENT. PRECIP TYPE ON TUESDAY WOULD BE MORE QUESTIONABLE...BUT FOR
NOW...GRIDS ARE DRY. KEPT FORECAST DRY FOR THE REST OF THE LONG
TERM FORECAST...ALONG WITH TEMPS THAT ARE NEAR TO SLIGHTLY ABOVE
CLIMATOLOGY /WHICH MAKES SENSE GIVEN THE LACK OF SNOW NOW ACROSS THE
AREA/.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
937 AM CST THU DEC 15 2011
.DISCUSSION...WIND SPEEDS AND TEMPERATURES THE MAIN CONCERN TODAY.
AREA OF CONCERN FOR WIND SPEEDS IS THE NORTHERN VALLEY WHERE
CURRENT (1530Z) SPEEDS ARE 30 TO 45 MPH. STRONG 925MB COLD AIR
ADVECTION WITH 925MB WINDS SPEEDS AROUND 40 KNOTS. 5MB/3HR SFC
PRESSURE RISE ACROSS THIS AREA. THESE STRONGER WINDS SHOULD OCCUR
FOR LESS THAN AN HOUR...MAINLY ASSOCIATED WITH 925MB COLD AIR
ADVECTION. 12Z RUC INDICATES THESE CONDITIONS WILL BE BRIEF AND
THUS NO WIND ADVISORY WILL BE REQUIRED...BUT DID ISSUE A NOWCAST.
STRONGEST FORCING FOR THESE STRONGER WINDS INDICATED TO REMAIN
ACROSS THE NE FA. FOR THE MOST PART...WITH WEAK COLD AIR
ADVECTION...EXPECT WIND SPEEDS 20 TO 30 MPH GRADUALLY DECREASING
AS SFC HIGH MOVES IN FROM THE WEST.
STRONGEST COLD AIR ADVECTION ACROSS THE NE FA...AND EXPECT TEMPS
TO FALL THROUGH THE DAY...WITH STEADY TEMPS LIKELY ACROSS THE SW
FA WHERE COLD AIR TEMP ADVECTION IS WEAKER.
ADJUSTED FORECAST TO ABOVE THINKING...LEADING TO SOME MINOR
CHANGES.
&&
.AVIATION...CIGS HAVE GENERALLY BEEN RISING FROM THE NORTHWEST AS
WINDS ALSO INCREASE. EXPECT RISING CIGS TO CONTINUE FROM NORTHWEST
TO SOUTHEAST ACROSS THE FORECAST AREA. SOME FLURRIES/SNOW SHOWERS
WILL MOVE ACROSS THE AREA TODAY. GUSTY WINDS FROM THE NORTHWEST
ARE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 428 AM CST THU DEC 15 2011/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT.
ECMWF WAS THE FASTER SOLUTION COMPARED TO THE NAM, GFS AND GEM. GEM
WAS THE SLOWEST AND THE GFS AND NAM A COMPROMISE THROUGH 48 HOURS.
WILL USE THE NAM AND GFS. QUITE PROGRESSIVE UPPER AIR PATTERN OVER
THE NORTHERN PLAINS. WATER VAPOR LOOP INDICATED SEVERAL SHORT WAVES
UPSTREAM AND WILL MOE ACROSS THE AREA NEARLY EACH DAY THIS PERIOD.
WATER VAPOR LOOP INDICATED A SHORT WAVE OVER SOUTHERN MAN AND WAS
MOVING SOUTHEAST ABOUT 40 KNOTS. FEW LIGHT SNOW SHOWERS ON
RADAR. SO WILL ADD LOW POPS NORTHEAST AND FLURRIES/SNOW SHOWERS
ELSEWHERE TODAY AND SHIFT EAST THROUGH THE DAY.
ANOTHER SHORT WAVE OVER THE BC COAST WILL MOVE INTO THE FORECAST
AREA LATE TONIGHT. MODELS ARE A LITTLE FASTER. SO WILL ADD LOW POPS
FOR LATE TONIGHT IN SOUTH AND WEST AND UP POPS SOUTH FRI.
ANOTHER SHORT WAVE SOUTH OF THE ALEUTIAN CHAIN WILL MOVE THROUGH SAT
AND IS EXPECTED TO AFFECT THE NORTH AND EAST ZONES.
LONG TERM (SUN-WED)...
NO HINTS AT CHANGES TO THE OVERALL PATTERN. SFC LOW TO MOVE JUST
NORTH OF THE INTERNATIONAL BORDER ON SUNDAY WITH FCST AREA IN WARM
SECTOR WITH 850 MB TEMPS RANGING FROM ZERO IN THE FAR NORTHEAST TO
+7 IN THE FAR SOUTHWEST. WINDS ALSO TURN SOUTHWEST OVER SE ND AND
FEEL THIS AREA COULD EASILY REACH 40+ DEGREES SUN AFTN. SO COORD
WITH SURROUNDING OFFICES AND UPPED MODELED HIGH TEMPS FOR SUNDAY FOR
SOUTHEAST-EAST CENTRAL ND. COLD FRONT WILL SWEEP THROUGH SUN EVE
WITH COLD ADVECTION FOLLOWED BY WARMER TEMPS ON TUESDAY. ANOTHER
WEAK SYSTEM TO PASS ALONG THE INTERNATIONAL BORDER REGION WED OR THU
AS MODEL DIFFERENCES EXIST BTWN ECMWF/GFS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
537 AM CST THU DEC 15 2011
.DISCUSSION.../ISSUED AT 407 AM CST/
STRONG NORTHERN STREAM WAVE WILL DELIVER AT LEAST A TEMPORARY RETURN
TOWARD MORE TYPICAL MID DECEMBER WEATHER ACROSS THE AREA TODAY.
MASSIVE STRATUS FIELD IN WAKE OF LEADING WAVE LIFTING TOWARD
NORTHERN WISCONSIN...AS WELL AS GOOD DOSE OF 25 TO 35 MPH NORTHWEST
WINDS. WITH CLOUDS...TEMPERATURES HAVE BEEN MORE SLUGGISH TO FALL
AS HAVE BEEN EQUALIZING WITH MIXING...BUT COLD AIR ADVECTION WILL
SOON BEGIN TO GET THE UPPER HAND...LIKELY KEEPING A DOWNWARD TREND
GOING WELL INTO THE MORNING BEFORE SOME DIURNAL RECOVERY. CLOUDS
WILL HAVE A LOT TO SAY ABOUT THIS...AND HAVE LITTLE OPTION THAN TO
BE EVEN MORE PESSIMISTIC GIVEN TRAJECTORY OF LOW LEVEL FLOW AND
THE CURRENT STRATUS FIELD. FOLLOWED CLOSER TO THE RUC AND FRIENDS
RELATIVE HUMIDITY FIELDS WHICH SEEMED TO HAVE AT LEAST A CLUE WHERE
STRATUS FIELD CURRENTLY RESIDES. OTHER ISSUE THAT HAS BEEN OCCURRING
OVERNIGHT HAS BEEN A FEW FLURRIES. THESE SEEM TO BE MOST CONCENTRATED
IN SMALLER AREAS WITHIN STRATUS FIELD WHERE CLOUD TOPS ARE JUST A
BIT COOLER THAN THE SURROUNDINGS...VERY EVIDENT WITH INITIAL AREA
MOVING THROUGH NORTHWEST IOWA AT 09Z...AND THEN SECONDARY AREA
UP ACROSS NORTHEAST SOUTH DAKOTA. WITH CLOUDS LAYER SNEAKING INTO
THE WARMER END OF THE DENDRITIC LAYER...WOULD NOT BE SURPRISED TO
GET CONTINUATION OF FLURRIES AT TIMES THROUGH AT LEAST MID TO LATE
MORNING WHEN SOME LIFT SUPPORT FROM NORTHERN STREAM UPPER WAVE.
MAY FINALLY GET TO SEE A MORE RAPID EROSION/ADVECTION OF THE CLOUD
BOUNDARY BY THE AFTERNOON AS CONTINUED DRIER LOW LEVEL AIR WORKS ON
CLOUDS FROM BOTTOM UP...AND SUBSIDENCE TO THE SOUTHWEST FLANK OF
UPPER WAVE WORKS FROM THE TOP. WINDS STRONGEST THROUGH THE EARLY
AFTERNOON HOURS...DIMINISHING FROM WEST WITH APPROACH OF RIDGE
AXIS...BUT HANGING ON A BIT STRONGER THROUGH ELEVATED SOUTHWEST
MINNESOTA AREAS WITH DEEPENING SYSTEM TO EAST AND MORE PERSISTENT
COLD AIR ADVECTION.
TONIGHT...CHILLY RIDGE WILL DRIFT EAST ACROSS THE AREA. WILL START
TO GET SOME RETURN FLOW STRENGTHENING A TOUCH FROM THE JAMES VALLEY
WESTWARD...AND THAT ALONG WITH THE THICKENING MID AND HIGH CLOUDS
WILL LIKELY BRING A NON DIURNAL TREND TO LOWS WEST...WITH MORE
TYPICAL FALLS UNDER LINGERING RIDGE THROUGH SOUTHEASTERN AREAS.
NORTHERN PORTION OF TROUGH DIGGING INTO THE SOUTHWEST WILL DETACH
AND MOVE THROUGH THE NORTHERN STREAM...RACING THROUGH THE NORTHERN
PLAINS ON FRIDAY. WEAK SURFACE LOW/TROUGH WILL PUSH QUICKLY ACROSS
SOUTH DAKOTA AND LIKELY TO REACH NORTHWEST IOWA BY EVENING. WHILE
MOISTURE WILL BE LIMITED...AND SPEED OF SYSTEM REDUCING POTENTIAL
EFFICIENCY OF LIFT...TEMPERATURES ARE FAIRLY FAVORABLE FOR ICE
CRYSTAL GROWTH. USED LOWER TO MID LEVEL WARM AIR ADVECTION/QG
FORCING TO TIME OUT A SMALL THREAT FOR SNOWFALL FROM MIDDAY THROUGH
THE AFTERNOON GLANCING THE NORTHEASTERN 1/3 OF THE AREA. LITTLE
WINDOW FOR MIXING BEHIND THE WEAK SURFACE WAVE ACROSS THE SOUTHWEST
CWA BEFORE COLD AIR ADVECTION TAKES TOLL ON TEMPERATURES LATER IN
THE AFTERNOON. /CHAPMAN
FRIDAY NIGHT INTO SATURDAY WILL SEE A RIDGE OF HIGH PRESSURE PASS
THROUGH WITH RETURN FLOW ALOFT DEVELOPING...POSSIBLY SETTING UP A
BIT OF AN INVERSION. BUT...AS IS THE STORY EARLY THIS WINTER...NO
SNOW COVER SHOUD ALLOW A FAVORABLE WIND FOR MIXING TO DEVELOP AND
TEMPERATURES WILL LIKELY CLIMB AT LEAST INTO THE UPPER 30S TO LWOER
40S IN MOST SPOTS. EVEN PLANNING ON SOME MID TO UPER 40S IN SOUTH
CENTRAL SOUTH DAKOTA. A FAIRLY WEAK PRESSURE GRADIENT ON SATURDAY
NIGHT WILL AID IN SOEM DROP OFF IN TEMPERATURES...BUT STILL LOOKING
WELL ABOVE NORMAL.
IN THE LATTER PERIODS(SUN/WED)...A MARGINALLY AGREED UPON JET STREAK
WILL TRAVERSE THE NORTHERN PLAINS EARLY IN THE PERIOD...DROPPING A
COLD FRONT THROUGH ON MONDAY. A SOUTHERN STREAM CUT OFF LOW WILL
MOVE THROUGH KANSAS INTO MISSOURI AND SHOULD NOT REALLY AFFECT THE
AREA. SPLIT FLOW INTENSIFIES DURING THE SECOND HALF OF THE
PERIOD...ALTHOUGH THE MODELS DO INDICATE A DEEPER TROUGH TRYING TO
CARVE OUT OVER THE WESTERN UNITED STATES. HOWEVER...WITH A FAIRLY
STRONG NORTHERN STREAM IT APPEARS THAT IT WILL EJECT POSITIVELY
TILTED THUS NOT CREATING MUCH OF A PROBLEM FOR THE AREA. SO...WILL
GO ABOVE OR AT THE WARMEST GUIDANCE ON SUNDAY WITH A VERY FAVORABLE
FLOW AND ABSOLUTELY NO SNOW COVER ANYWHERE TO SPEAK OF. WILL
INCREASE LOWS A BIT ON SUNDAY NIGHT/MONDAY MORNING CLOSER TO THE RAW
OUTPUT WHICH GENERALLY HANDLES NIGHTS WITH WIND BETTER. COLDER AIR
IN ON MONDAY BUT WILL STILL LEAN TOWARDS MILDER GUIDANCE NUMBERS
WITH NO SNOW ON GROUND. MONDAY NIGHT A LITTLE TRICKY WITH A RIDGE OF
HIGH PRESSURE SLIPPING THROUGH...SO LOWERED LOWS JUST A BIT TO
COMPENSATE FOR THE POTENTIAL FOR A RADIATIONAL DROP OFF...ESPECIALLY
IN THE SOUTHERN CWA. NO BIG CHANGES FOR TUESDAY AND WEDNESDAY THIS
TIME AROUND...JUST A BIT WARMER ON TUESDAY WITH DECENT POTENTIAL LOW
LEVEL WIND FIELD. /08
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
WIDESPREAD MVFR CIGS IN STRATUS FIELD HAVE BEEN GRADUALLY CLIMBING
INTO THE LOWER END VFR WEST OF INTERSTATE 29...AS DRIER LOW LEVEL
AIR PUSHES INTO THE AREA. THESE CEILINGS WILL BE SLOW TO ERODE
EASTWARD THROUGH THE DAY...BUT SHOULD START TO GET SOME CLEARING
OF NOTE WORKING TOWARD THE KHON AREA AROUND 18Z...KSUX 20Z...AND
KFSD AROUND 22Z. OTHER SIGNFICANT CONCERN TODAY TO AVIATION IS THE
STRONG NORTHWEST WINDS...WHICH WILL LIKELY GUST AT OR ABOVE 25 KNOTS
THROUGH MID TO LATE AFTERNOON...WITH GUSTS TO AROUND 35 KNOTS ACROSS
SOUTHWEST MINNESOTA AND NORTHWEST IOWA THROUGH MIDDAY. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
527 AM CST THU DEC 15 2011
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN ABUNDANCE OF STRATUS CLOUDS CONTINUE TO MOVE SOUTHEAST ACROSS
THE DAKOTAS...WITH THE EXTENT OF IT PUSHING WELL NORTH BACK INTO
SOUTHERN CANADA. WESTERN EDGE OF CLOUDS ACROSS SOUTH DAKOTA LIES
ALONG THE MISSOURI RIVER. ALTHOUGH...WITH A SOUTHEAST MOVEMENT TO
THE CLOUDS AND PLENTY LEFT UPSTREAM...EXPECTING THE EASTERN CWA TO
REMAIN IN CLOUDS MOST OF THE DAY. THE WESTERN CWA WILL LIKELY SEE
A BIT MORE SUNSHINE TODAY. MOST MODELS HAVING A HARD TIME PICKING
UP ON THE CLOUD COVER BUT THE RUC13 850 RH SEEMS TO HAVE A BETTER
HANDLE ON THINGS. IT WOULD SUGGEST CLOUD COVER THROUGH THE
AFTERNOON ACROSS THE EASTERN CWA...WITH THE WESTERN CWA IN MORE
SUNSHINE...AS PREVIOUSLY STATED. HAVE ALSO BEEN SEEING SCT
FLURRIES WITH THE STRATUS CLOUDS. PLENTY OF THAT UPSTREAM AS WELL
WITH KBIS AND KMBX RADARS SHOWING FLURRIES. EVEN OBS IN SOUTHERN
CANADA SHOWING -SN FROM TIME TO TIME. HAVE THEREFORE ADDED SCT
FLURRIES TO FORECAST THROUGH 18Z AND COULD BE A SITUATION WHERE IT
MAY NEED TO BE EXTENDED FURTHER INTO THE AFTERNOON ACROSS THE
EASTERN CWA WHEREVER STRATUS CLOUDS HANG ON THE LONGEST.
AGAIN...PLENTY OF ACTIVITY NOTED WELL UPSTREAM INTO SOUTHERN
CANADA. NORTHWEST WINDS WILL REMAIN BREEZY TODAY AS THE PRESSURE
GRADIENT REMAINS FAIRLY TIGHT WITH HIGH PRESSURE BUILDING IN.
HIGHEST SPEEDS WILL BE ACROSS THE EASTERN CWA WITH A DROP OFF IN
WINDS ACROSS THE WESTERN COUNTIES BY THIS AFTERNOON.
SFC HIGH WILL SETTLE IN OVER THE AREA TONIGHT BRINGING LIGHT
WINDS. NEXT ITEM TO WATCH WILL BE THE WEAK SHORTWAVE CROSSING THE
DAKOTAS LATE TONIGHT AND FRIDAY. MODELS STILL PEGGING MOST OF
THE LIGHT SNOWFALL ACROSS ND BUT THERE HAS BEEN A SLIGHT SHIFT
FURTHER SOUTH INTO NORTHERN SD. COUPLE MODELS BRINGING LIGHT QPF
INTO THE NORTHEASTERN COUNTIES AND SREF PROBS FOR .01 SHOWING
DECENT CHANCES ACROSS THE NORTHEASTERN CWA AS WELL. HAVE THEREFORE
INCREASED POPS SLIGHTLY FOR FRIDAY.
FOCUS WILL THEN SHIFT TO THE DEGREE OF WARMTH ON SATURDAY AS MILD
PACIFIC AIR BEGINS TO STREAM ACROSS THE NORTHERN PLAINS. WARM
FRONT CROSSES THE AREA DURING THE DAY SATURDAY WITH WINDS TURNING
WESTERLY. 850 MB TEMPS RISE TO JUST ABOVE ZERO C. WITH THE WIND
SHIFT AND A DECENT AMOUNT OF SUN...WILL SEE TEMPS RISE INTO THE
30S AND 40S.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
NOT MUCH TO TALK ABOUT IN THE EXTENDED FORECAST. CONSENSUS MODELS
ARE STILL GOING WITH CONTINUED DRY CONDITIONS. INTERESTINGLY THE
GFS IS STARTING TO HINT AT THE POSSIBILITY OF SOME PRECIP AT THE
END OF THE FORECAST PERIOD ASSOCIATED WITH THE NEXT UPPER TROF
THAT DIGS INTO THE PLAINS SO WILL NEED TO KEEP AN EYE ON HOW THAT
SYSTEM DEVELOPS. FOR NOW THOUGH LEFT THE FORECAST PRECIP FREE.
WITH THE LACK OF SNOW ON THE GROUND TEMPERATURES WILL ALSO
CONTINUE THE ABOVE NORMAL TREND WITH HIGHS STAYING NEAR 30 OR EVEN
CLIMBING INTO THE 40S THROUGH THE PERIOD.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
STRATUS REMAINS ACROSS THE REGION BUT HAS LIFTED TO AOA
2KFT. CIGS WILL BEGIN TO BREAK UP LATE THIS AFTERNOON...AND VISBY
IS EXPECTED TO REMAIN VFR. WINDS OUT OF THE NORTHWEST AT 20G30MPH
WILL CONTINUE THROUGH THIS MORNING BUT GRADUALLY DIMINISH FROM
WEST TO EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
407 AM CST THU DEC 15 2011
.DISCUSSION.../ISSUED AT 400 AM CST/
STRONG NORTHERN STREAM WAVE WILL DELIVER AT LEAST A TEMPORARY RETURN
TOWARD MORE TYPICAL MID DECEMBER WEATHER ACROSS THE AREA TODAY.
MASSIVE STRATUS FIELD IN WAKE OF LEADING WAVE LIFTING TOWARD
NORTHERN WISCONSIN...AS WELL AS GOOD DOSE OF 25 TO 35 MPH NORTHWEST
WINDS. WITH CLOUDS...TEMPERATURES HAVE BEEN MORE SLUGGISH TO FALL
AS HAVE BEEN EQUALIZING WITH MIXING...BUT COLD AIR ADVECTION WILL
SOON BEGIN TO GET THE UPPER HAND...LIKELY KEEPING A DOWNWARD TREND
GOING WELL INTO THE MORNING BEFORE SOME DIURNAL RECOVERY. CLOUDS
WILL HAVE A LOT TO SAY ABOUT THIS...AND HAVE LITTLE OPTION THAN TO
BE EVEN MORE PESSIMISTIC GIVEN TRAJECTORY OF LOW LEVEL FLOW AND
THE CURRENT STRATUS FIELD. FOLLOWED CLOSER TO THE RUC AND FRIENDS
RELATIVE HUMIDITY FIELDS WHICH SEEMED TO HAVE AT LEAST A CLUE WHERE
STRATUS FIELD CURRENTLY RESIDES. OTHER ISSUE THAT HAS BEEN OCCURRING
OVERNIGHT HAS BEEN A FEW FLURRIES. THESE SEEM TO BE MOST CONCENTRATED
IN SMALLER AREAS WITHIN STRATUS FIELD WHERE CLOUD TOPS ARE JUST A
BIT COOLER THAN THE SURROUNDINGS...VERY EVIDENT WITH INITIAL AREA
MOVING THROUGH NORTHWEST IOWA AT 09Z...AND THEN SECONDARY AREA
UP ACROSS NORTHEAST SOUTH DAKOTA. WITH CLOUDS LAYER SNEAKING INTO
THE WARMER END OF THE DENDRITIC LAYER...WOULD NOT BE SURPRISED TO
GET CONTINUATION OF FLURRIES AT TIMES THROUGH AT LEAST MID TO LATE
MORNING WHEN SOME LIFT SUPPORT FROM NORTHERN STREAM UPPER WAVE.
MAY FINALLY GET TO SEE A MORE RAPID EROSION/ADVECTION OF THE CLOUD
BOUNDARY BY THE AFTERNOON AS CONTINUED DRIER LOW LEVEL AIR WORKS ON
CLOUDS FROM BOTTOM UP...AND SUBSIDENCE TO THE SOUTHWEST FLANK OF
UPPER WAVE WORKS FROM THE TOP. WINDS STRONGEST THROUGH THE EARLY
AFTERNOON HOURS...DIMINISHING FROM WEST WITH APPROACH OF RIDGE
AXIS...BUT HANGING ON A BIT STRONGER THROUGH ELEVATED SOUTHWEST
MINNESOTA AREAS WITH DEEPENING SYSTEM TO EAST AND MORE PERSISTENT
COLD AIR ADVECTION.
TONIGHT...CHILLY RIDGE WILL DRIFT EAST ACROSS THE AREA. WILL START
TO GET SOME RETURN FLOW STRENGTHENING A TOUCH FROM THE JAMES VALLEY
WESTWARD...AND THAT ALONG WITH THE THICKENING MID AND HIGH CLOUDS
WILL LIKELY BRING A NON DIURNAL TREND TO LOWS WEST...WITH MORE
TYPICAL FALLS UNDER LINGERING RIDGE THROUGH SOUTHEASTERN AREAS.
NORTHERN PORTION OF TROUGH DIGGING INTO THE SOUTHWEST WILL DETACH
AND MOVE THROUGH THE NORTHERN STREAM...RACING THROUGH THE NORTHERN
PLAINS ON FRIDAY. WEAK SURFACE LOW/TROUGH WILL PUSH QUICKLY ACROSS
SOUTH DAKOTA AND LIKELY TO REACH NORTHWEST IOWA BY EVENING. WHILE
MOISTURE WILL BE LIMITED...AND SPEED OF SYSTEM REDUCING POTENTIAL
EFFICIENCY OF LIFT...TEMPERATURES ARE FAIRLY FAVORABLE FOR ICE
CRYSTAL GROWTH. USED LOWER TO MID LEVEL WARM AIR ADVECTION/QG
FORCING TO TIME OUT A SMALL THREAT FOR SNOWFALL FROM MIDDAY THROUGH
THE AFTERNOON GLANCING THE NORTHEASTERN 1/3 OF THE AREA. LITTLE
WINDOW FOR MIXING BEHIND THE WEAK SURFACE WAVE ACROSS THE SOUTHWEST
CWA BEFORE COLD AIR ADVECTION TAKES TOLL ON TEMPERATURES LATER IN
THE AFTERNOON. /CHAPMAN
FRIDAY NIGHT INTO SATURDAY WILL SEE A RIDGE OF HIGH PRESSURE PASS
THROUGH WITH RETURN FLOW ALOFT DEVELOPING...POSSIBLY SETTING UP A
BIT OF AN INVERSION. BUT...AS IS THE STORY EARLY THIS WINTER...NO
SNOW COVER SHOUD ALLOW A FAVORABLE WIND FOR MIXING TO DEVELOP AND
TEMPERATURES WILL LIKELY CLIMB AT LEAST INTO THE UPPER 30S TO LWOER
40S IN MOST SPOTS. EVEN PLANNING ON SOME MID TO UPER 40S IN SOUTH
CENTRAL SOUTH DAKOTA. A FAIRLY WEAK PRESSURE GRADIENT ON SATURDAY
NIGHT WILL AID IN SOEM DROP OFF IN TEMPERATURES...BUT STILL LOOKING
WELL ABOVE NORMAL.
IN THE LATTER PERIODS(SUN/WED)...A MARGINALLY AGREED UPON JET STREAK
WILL TRAVERSE THE NORTHERN PLAINS EARLY IN THE PERIOD...DROPPING A
COLD FRONT THROUGH ON MONDAY. A SOUTHERN STREAM CUT OFF LOW WILL
MOVE THROUGH KANSAS INTO MISSOURI AND SHOULD NOT REALLY AFFECT THE
AREA. SPLIT FLOW INTENSIFIES DURING THE SECOND HALF OF THE
PERIOD...ALTHOUGH THE MODELS DO INDICATE A DEEPER TROUGH TRYING TO
CARVE OUT OVER THE WESTERN UNITED STATES. HOWEVER...WITH A FAIRLY
STRONG NORTHERN STREAM IT APPEARS THAT IT WILL EJECT POSITIVELY
TILTED THUS NOT CREATING MUCH OF A PROBLEM FOR THE AREA. SO...WILL
GO ABOVE OR AT THE WARMEST GUIDANCE ON SUNDAY WITH A VERY FAVORABLE
FLOW AND ABSOLUTELY NO SNOW COVER ANYWHERE TO SPEAK OF. WILL
INCREASE LOWS A BIT ON SUNDAY NIGHT/MONDAY MORNING CLOSER TO THE RAW
OUTPUT WHICH GENERALLY HANDLES NIGHTS WITH WIND BETTER. COLDER AIR
IN ON MONDAY BUT WILL STILL LEAN TOWARDS MILDER GUIDANCE NUMBERS
WITH NO SNOW ON GROUND. MONDAY NIGHT A LITTLE TRICKY WITH A RIDGE OF
HIGH PRESSURE SLIPPING THROUGH...SO LOWERED LOWS JUST A BIT TO
COMPENSATE FOR THE POTENTIAL FOR A RADIATIONAL DROP OFF...ESPECIALLY
IN THE SOUTHERN CWA. NO BIG CHANGES FOR TUESDAY AND WEDNESDAY THIS
TIME AROUND...JUST A BIT WARMER ON TUESDAY WITH DECENT POTENTIAL LOW
LEVEL WIND FIELD. /08
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
WIDESPREAD MVFR CEILINGS CAN BE EXPECTED THROUGH 15Z AND THEN
GRADUALLY BECOME VFR FROM THE NORTHWEST. GUSTY NORTHWEST SURFACE
WINDS WILL GUST TO 30 KNOTS THROUGH 00Z FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 AM CST THU DEC 15 2011
.SHORT TERM...TODAY THROUGH SATURDAY
343 AM CST THU DEC 15 2011
MAIN FORECAST CONCERNS ARE ON BLUSTERY NORTHWEST WINDS TODAY/CHANCES
FOR FREEZING DRIZZLE THIS MORNING...AND CLOUD COVER/FLURRIES
THROUGH THE DAY. FOCUS THEN TURNS TO SNOW CHANCES LATE FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A COLD FRONT EXTENDING FROM THE
NORTHERN LOWER MICHIGAN SOUTHWEST INTO NORTH CENTRAL MISSOURI.
SPRINKLES CONTINUE ACROSS THE FORECAST AREA THIS MORNING AS
STRATUS AND LOW LEVEL LIFT REMAIN IN PLACE. COLDER AIR WAS
FILTERING INTO THE REGION WITH TEMPERATURES FALLING INTO THE MID
30S. LOOK FOR TEMPERATURES TO CONTINUE FALLING THIS MORNING...WITH
THE POTENTIAL FOR FREEZING DRIZZLE THROUGH LATE MORNING.
LOW LEVEL SATURATION AND LIFT MAY PRODUCE SOME LIGHT FREEZING
DRIZZLE OR SNOW THIS MORNING...THEN SOME FLURRIES THIS AFTERNOON.
OTHERWISE PLAN ON CLOUDY SKIES TODAY WITH LOW LEVEL MOISTURE
REMAINING IN PLACE. MODELS ARE HAVING A DIFFICULT TIME HANDLING
THE LOW LEVEL MOISTURE TODAY...EXCEPT FOR THE RUC. HAVE TRENDED
CLOUDS AND TEMPERATURES TOWARDS THE RUC TODAY. ANY LINGERING
FREEZING DRIZZLE IS EXPECTED TO SWITCH OVER TO FLURRIES BY THIS
AFTERNOON AS COLDER AIR ALOFT MOVES IN. MESOSCALE MODELS INDICATE
PATCHY PRECIP ACROSS SOUTHEAST MINNESOTA AND MUCH OF WESTERN
WISCONSIN INTO THE AFTERNOON HOURS. THIS SIGNAL IS OFTEN
INDICATIVE OF FLURRIES OR DRIZZLE SO WILL HAVE TO KEEP A CLOSE EYE
ON THIS THROUGH THE MORNING HOURS. FORECAST SOUNDINGS SUGGEST MUCH
OF THE LOW LEVEL LIFT WILL BE LOST BY LATE AFTERNOON ALONG WITH
DRIER LOW LEVEL AIR PUSHING IN. THIS SHOULD END ANY LINGERING
PRECIPITATION. LOOK FOR BLUSTERY NORTHWEST WINDS TODAY...WITH
SPEEDS OF 15 TO 25 MPH AND GUSTS UP TO 40 MPH POSSIBLE. IT APPEARS
THAT WINDS WILL STAY BELOW ADVISORY CRITERIA SO WILL NOT BE
HOISTING A WIND ADVISORY TODAY. LOOK FOR HIGHS TO OCCUR EARLY THIS
MORNING...WITH TEMPERATURES FALLING THROUGH THE MORNING INTO THE
AFTERNOON. PLAN ON TEMPERATURES FALLING INTO THE UPPER 20S TO
LOWER 30S BY EARLY AFTERNOON. THE MAIN CONCERN TONIGHT WILL BE
CLOUD COVER AND LOW TEMPERATURES. LOOKING AT THE STRATUS
UPSTREAM...AND THE TRAJECTORIES...WOULD EXPECT THE CLOUDS TO
LINGER THROUGH TONIGHT. HAVE ADJUSTED LOWS UPWARD SLIGHTLY TO
ACCOUNT FOR THE EXPECTED CLOUD COVER. SHOULD SEE LOWS FALL INTO
THE UPPER TEENS TO LOWER 20S.
SURFACE HIGH PRESSURE IS EXPECTED TO MOVE OVER THE UPPER MISSISSIPPI
RIVER VALLEY ON FRIDAY WITH CLOUDS DECREASING ACROSS THE AREA EARLY
IN THE DAY...THEN GRADUALLY INCREASING FROM THE NORTHWEST LATE IN
THE AFTERNOON AS ANOTHER SYSTEM MOVES IN. 15.00 MODELS INDICATE A
SHORTWAVE TROUGH MOVING FROM NORTHEAST MONTANA THROUGH THE DAKOTAS
EARLY ON FRIDAY. THE SHORTWAVE WILL MOVE INTO THE FORECAST AREA LATE
FRIDAY AFTERNOON INTO FRIDAY EVENING...WITH POTENTIAL VORTICITY
ADVECTION OF 15 PVU/S IN THE 500-300 MB LAYER...MOVING INTO THE
FORECAST AREA EARLY. ISENTROPIC LIFT WILL INCREASE ACROSS THE AREA ON
THE 275-285 K SURFACES AS THE WAVE MOVES THROUGH. FORECAST SOUNDINGS
ARE SHOWING A 5000 FT DENDRITIC GROWTH ZONE FRIDAY EVENING. SHOULD
SEE A BRIEF SHOT OF SNOW FRIDAY EVENING. GIVEN THE SHORT DURATION OF
FORCING OVER THE AREA...SNOW ACCUMULATION SHOULD BE ON THE LIGHT
SIDE...RANGING FROM A HALF INCH TO PERHAPS A FEW LOCATIONS RECEIVING
AROUND 2 INCHES. HAVE INCREASED PRECIPITATION CHANCES ACROSS MUCH OF
THE FORECAST AREA FRIDAY EVENING INTO LATE FRIDAY NIGHT. CURRENT
THINKING IS THAT THE SNOW BAND WILL SET UP FROM SOUTHEAST MINNESOTA
THROUGH CENTRAL WISCONSIN...WITH THE GREATEST ACCUMULATIONS OCCURRING
ACROSS THESE AREAS. THE SNOW SHOULD TAPER OFF AFTER MIDNIGHT AS THE
SHORTWAVE MOVES INTO EASTERN WISCONSIN. LOOK FOR LOW TEMPERATURES TO
RANGE FROM THE MID TO UPPER TEENS ACROSS SOUTHEAST MINNESOTA THROUGH
NORTH CENTRAL WISCONSIN...TO THE LOWER 20S ACROSS FAR SOUTHWEST
WISCONSIN.
NORTHWEST FLOW ALOFT IS EXPECTED TO PERSIST ACROSS THE AREA ON
SATURDAY. A SHORTWAVE TROUGH WILL MOVE ACROSS LAKE SUPERIOR AND FAR
NORTHERN WISCONSIN DURING THE DAYTIME HOURS. MODELS ARE GENERATING
SOME LIGHT SNOW WITH THIS FEATURE AS IT MOVES THROUGH. THE SNOW
SHOULD STAY NORTH OF THE FORECAST AREA BUT WILL HAVE TO KEEP A CLOSE
WATCH ON THE NEXT SET OF MODEL RUNS. A FEW FLURRIES COULD FALL
ACROSS NORTH CENTRAL WISCONSIN AS THIS WAVE MOVES THROUGH. THE MAIN
IMPACT THE WAVE WILL HAVE ON THE FORECAST AREA...IS INCREASING CLOUD
COVER. LOOK FOR HIGH TEMPERATURES ON SATURDAY TO RANGE FROM THE
UPPER 20S ACROSS NORTH CENTRAL WISCONSIN TO THE MID 30S ACROSS
NORTHEAST IOWA THROUGH FAR SOUTHWEST WISCONSIN. 250 MB JET STREAK
WILL MOVE ACROSS THE REGION SATURDAY NIGHT. A SURFACE RIDGE IS
EXPECTED TO MOVE DURING THE OVERNIGHT HOURS PROVIDING MOSTLY CLEAR
SKIES. 850 MB TEMPERATURES WILL WARM THROUGH THE NIGHT...STARTING
OUT AROUND -2C AT 00Z AND WARMING TO PLUS 2 C BY 12 SUNDAY. FORECAST
SOUNDINGS ARE SHOWING THE COLD AIR HOLDING STRONG NEAR THE SURFACE
AS WARM AIR MOVES IN ALOFT. THE SOUNDINGS ALSO SATURATE NEAR THE
SURFACE SUGGESTING SOME LOW CLOUD/FOG DEVELOPMENT. LOOK FOR LOWS TO
FALL INTO THE 20S SATURDAY NIGHT.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
343 AM CST THU DEC 15 2011
15.00 MEDIUM RANGE MODELS CONTINUE TO SHOW A SPLIT FLOW PATTERN
PERSISTING ACROSS THE CONUS INTO THE MIDDLE OF NEXT WEEK. A COLD
FRONT IS EXPECTED TO SAG SOUTH ACROSS THE FORECAST AREA ON LATE
SUNDAY INTO MONDAY. THIS SYSTEM MAY BRING SOME LIGHT SNOW TO THE
AREA BUT MOISTURE WILL BE LACKING...SO ANY SNOWFALL AMOUNTS WOULD
LIKELY BE MINIMAL. THE GFS AND NAM TAKE AN UPPER LOW OVER THE
SOUTHWEST CONUS...EAST INTO THE SOUTHERN PLAINS LATE MONDAY INTO
TUESDAY. THE MODELS THEN TAKE THE LOW ACROSS THE MID MISSISSIPPI
RIVER VALLEY LATE TUESDAY INTO WEDNESDAY. MUCH OF THE PRECIPITATION
LOOKS TO STAY WELL SOUTH OF THE AREA. A MAJORITY OF THE GFS ENSEMBLE
MEMBERS ARE ALSO IN FAVOR OF THE SOUTHERN TRACK. THE GEM OFFERS A
DIFFERENT SOLUTION...TAKING THE LOW INTO THE CENTRAL PLAINS LATE
MONDAY AND LIFTING IT ACROSS SOUTHERN IOWA INTO SOUTHEAST WISCONSIN ON
TUESDAY. WILL CONTINUE A MODEL CONSENSUS BLEND DURING THIS
TIMEFRAME...KEEPING PRECIPITATION CHANCES MAINLY ALONG AND SOUTH OF
THE I-90 CORRIDOR LATE MONDAY NIGHT INTO TUESDAY. PLAN ON HIGHS
GENERALLY IN THE 30S MONDAY THROUGH WEDNESDAY...WITH LOWS IN THE 20S.
&&
.AVIATION...TODAY AND TONIGHT
535 AM CST THU DEC 15 2011
CEILING HEIGHTS AND WINDS ARE THE MAIN CONCERN. STRONG COLD
ADVECTION IN THE WAKE OF THE FRONT WILL CONTINUE THROUGHOUT THE DAY
WITH THE PRESSURE GRADIENT TIGHTENING. MODEL SOUNDING SUGGEST GUST
POTENTIAL TO 35 KNOTS TODAY...ESPECIALLY AT KRST AND THUS HAVE
RAISED WINDS FROM PREVIOUS SET OF TAFS. THESE WINDS WILL RESULT IN
STRONG CROSS WINDS FOR NORTH SOUTH RUNWAYS. THESE WINDS WILL
DIMINISH THIS EVENING...UNDER 10 KNOTS BETWEEN 03Z-06Z.
AS FOR CEILING HEIGHTS...A SLOW INCREASE IN CEILINGS IS EXPECTED
TODAY...BUT REMAINING IN THE MVFR CATEGORY. THE QUESTION IS WILL
THERE BE ANY CLEARING TONIGHT. MODELS WOULD SAY YES...AS THEY ARE
RATHER BULLISH ON PUSHING THE STRATUS OUT OF THE AREA. CONFIDENCE
NOT HIGH ON THIS...BUT DID BRING SCATTERED CONDITIONS IN BETWEEN 04Z-06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 AM CST THU DEC 15 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
244 PM CST THU DEC 15 2011
.SYNOPSIS...
12Z UA ANALYSIS HAS A LLJ RUNNING FROM OKLAHOMA INTO NEW ENGLAND.
SEVERAL TROFS RAN FROM THE WESTERN GREAT LAKES INTO THE NORTHERN
PLAINS WHERE ANOTHER LLJ WAS LOCATED. SATELLITE TRENDS THROUGH EARLY
AFTERNOON SHOW THE CLOUDS BEGINNING TO BREAK UP AS STRONG SUBSIDENCE
DEVELOPS ACROSS THE PLAINS AND UPPER MISSISSIPPI VALLEY.
18Z SFC ANALYSIS HAS THE COLD FRONT FROM LAKE HURON INTO EASTERN
TEXAS WITH HIGH PRESSURE IN THE PLAINS. SEVERAL TROFS RAN FROM THE
WESTERN LAKES INTO THE UPPER MISSISSIPPI VALLEY. DEW POINTS AHEAD OF
THE FRONT WERE IN THE 50S AND 60S WITH 30S AND 40S IMMEDIATELY
BEHIND THE FRONT. DEW POINTS IN THE TEENS AND 20S WERE IN THE PLAINS
AND PARTS OF THE MIDWEST.
&&
.SHORT TERM...TONIGHT AND FRIDAY...
QUIET WX WITH SEASONABLE TEMPERATURES WILL BE SEEN TONIGHT AND
FRIDAY. WINDS WILL CONTINUE TO DECREASE LATE THIS AFTERNOON AND
EVENING AS THE STRONGEST ISALLOBARIC CHANGE CONTINUES TO MOVE EAST
OF THE AREA. RUC TRENDS INDICATE THAT STRONG SUBSIDENCE IS
DEVELOPING BEHIND THE DEPARTING SHORTWAVE AND SATELLITE DOES SHOW
MORE BREAKS BEGINNING TO DEVELOP IN THE CLOUD SHIELD.
BASED ON CURRENT SATELLITE AND RUC TRENDS...CLOUDS WILL CONTINUE TO
SLOWLY BREAK UP FOR THE REMAINDER OF THE AFTERNOON WITH CLEARING
DEVELOPING ACROSS THE CWFA LATE THIS AFTERNOON OR EVENING.
..08..
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
A WEAK CLIPPER SHOULD SLIDE SOUTHEAST FRIDAY EVENING...BRINGING SOME
MID CLOUDS TO THE CWA...AND AN OUTSIDE CHANCE FOR A SNOW
SHOWER...BUT MORE LIKELY FLURRIES IN THE NORTH. THIS VERY MINOR
EVENT PASSES QUICKLY FRIDAY NIGHT AND LEAVES SATURDAY AND SUNDAY
WITH VERY PLEASANT LATE FALL WEATHER. HIGHS IN THE MID TO UPPER 30S
SATURDAY AND LOWER TO MID 40S SUNDAY. THIS ENDS THE PERIOD OF HIGH
CONFIDENCE IN THE EXTENDED.
THE MODELS ARE IN TWO CAMPS NOW WITH RESPECT TO THE MONDAY THROUGH
WEDNESDAY STORM. THE GEM...UKMET...AND GFS RUNS SINCE 00Z LAST NIGHT
HAVE GONE FARTHER NORTH...AND BRING A SIMILAR STORM TO THE MIDWEST
THAN WAS SEEN IN THE PAST 2 DAYS. HOWEVER...THE ECMWF HAS TRENDED
SOUTH...AND CLIPS THE CWA WITH LIGHT SNOW ON TUESDAY/TUESDAY NIGHT.
THE MAJOR DIFFERENCE BETWEEN THESE MODELS BOILS DOWN TO HOW THEY
HANDLE A SEPARATE SHORT WAVE THAT ENTERS THE PACIFIC NORTHWEST
SATURDAY. THE GEM/UK/GFS ALL BRING THAT STORM INTO THE WA/OR
COAST...AND PHASE THAT WAVE/KICK THE CLOSED LOW NORTHEASTWARD AND
THEREFORE DEVELOP A SIGNIFICANT MIDWEST STORM. THE ECMWF BRINGS THIS
WAVE INTO CENTRAL BRITISH COLUMBIA...AND AS IT MOVES IT EAST...IT
OVER TOPS THE RIDGE ON THE WEST COAST VS KICKING THE LOW OUT WITH
IT. AFTER OVERTOPPING...IT SWEEPS HIGH PRESSURE AND COLD AIR DOWN
INTO THE MIDWEST FOR EARLY WEEK AND THEREFORE SUPPRESSES THE STORM
SYSTEM SOUTH. SUCH A SMALL DIFFERENCE...RESULTS IN A MAJOR
DIFFERENCES IN OUR WEATHER. THIS WAVE IN QUESTION IS REAL...BUT
FOUND OVER THE NORTH CENTRAL PACIFIC OCEAN AS OF NOW...AND IS WITHIN
A FAST BAND OF WESTERLY FLOW SOUTH OF A MAJOR ALEUTIAN LOW.
THUS...GLOBAL MODELS WILL NO LIKELY LOCK CORRECTLY ONTO ITS POSITION
AND STRENGTH FOR SOME DAYS. PREDICTING THE WEATHER IS A
CHALLENGE...BUT THIS ONE WILL TAKE TIME TO BE WORKED OUT. UNTIL WE
KNOW FOR SURE WHAT LATITUDE THIS WAVE MAKES LANDFALL IN THE PAC
NORTHWEST...WE WILL NO KNOW WHETHER IT OVERTOPS OR PHASES/KICKS OUT
OUR CLOSED LOW IN THE SOUTHWEST. TIME WILL CERTAINLY TELL.
OUR FORECAST REMAINS WET TO START...AND SNOWY TO END THIS
STORM...POPS ARE LOW...BUT SHOULD THE NORTHERN TRACK BY CORRECT...WE
NEED MUCH HIGHER POPS FOR THIS EVENT.
WEDNESDAY AND THURSDAY...ALL GLOBAL MODELS SHOW THE PATTERN
RELOADING FOR ANOTHER CUT OFF LOW IN THE SOUTHWEST. THIS SHOULD
PROVIDE ANOTHER DAY OR TWO OF QUIET WEATHER BEFORE ANOTHER POTENTIAL
EVENT.
..ERVIN..
&&
.AVIATION...
CIGS CONTINUE TO LIFT AND MOST LOCATIONS ARE GENERALLY 3KFT OR 4KFT
AGL. WINDS WILL DIMINISH THROUGH 06Z/16 WITH CLEARING TAKING PLACE.
HIGH PRESSURE BUILDING INTO THE MIDWEST WILL RESULT IN VFR
CONDITIONS THROUGH 00Z/17.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1130 AM CST THU DEC 15 2011
.AVIATION...
MVFR CONDITIONS WILL CONTINUE UNTIL CLOSE TO 00Z/16 WHEN VFR
CONDITIONS ARE EXPECTED TO DEVELOP. THE STRONGEST WINDS WILL BE
SEEN THROUGH 20Z/15 IN RESPONSE TO THE FALL/RISE PRESSURE COUPLET.
WINDS WILL BEGIN TO DECREASE AFT 21Z/15 AS HIGH PRESSURE BUILDS
INTO THE MIDWEST.
..08..
&&
.PREV DISCUSSION... /ISSUED 1036 AM CST THU DEC 15 2011/
UPDATE...
12Z UA DATA HAS A NICE TROF MOVING ACROSS IOWA WHICH IS AIDING IN
GENERATING THE DZ AND SOME VERY LIGHT RAIN. RUC TRENDS HAVE THE
SUPPORT FOR THE DZ MOVING EAST OF THE CWFA EARLY THIS AFTERNOON
AND RADAR EXTRAPOLATION SUPPORTS THIS AS WELL.
AS FOR THE WINDS...THE MAXIMUM ISALLOBARIC CHANGE IS CURRENTLY
MOVING ACROSS THE CWFA. SO THE STRONGEST WINDS WILL BE SEEN OVER
THE NEXT 4 HOURS BEFORE DECREASING. THERE ARE NO PLANS FOR ANY
HEADLINES FOR THE WIND BUT GUSTS TO 35 MPH WILL BE VERY LIKELY
INTO EARLY AFTERNOON.
BREAKS HAVE DEVELOPED IN THE CLOUD COVER BUT SATELLITE TRENDS ARE
INDICATING THESE ARE FILLING IN. AS THE STRONGER SUBSIDENCE
DEVELOPS BEHIND THE DEPARTING SHORTWAVE THIS AFTERNOON CLOUDS
SHOULD BEGIN TO BREAK UP WITH CLEARING OCCURRING ACROSS MUCH OF
THE AREA BY OR SHORTLY AFTER SUNSET.
TEMPERATURES WILL CONTINUE TO SLOWLY FALL THROUGH THE AFTERNOON.
ANY PEEKS OF SUN MAY RESULT IN A BRIEF RISE IN SOME AREAS.
AN UPDATE REFLECTING ALL THIS WILL BE AVAILABLE SHORTLY.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1036 AM CST THU DEC 15 2011
.UPDATE...
12Z UA DATA HAS A NICE TROF MOVING ACROSS IOWA WHICH IS AIDING IN
GENERATING THE DZ AND SOME VERY LIGHT RAIN. RUC TRENDS HAVE THE
SUPPORT FOR THE DZ MOVING EAST OF THE CWFA EARLY THIS AFTERNOON
AND RADAR EXTRAPOLATION SUPPORTS THIS AS WELL.
AS FOR THE WINDS...THE MAXIMUM ISALLOBARIC CHANGE IS CURRENTLY
MOVING ACROSS THE CWFA. SO THE STRONGEST WINDS WILL BE SEEN OVER
THE NEXT 4 HOURS BEFORE DECREASING. THERE ARE NO PLANS FOR ANY
HEADLINES FOR THE WIND BUT GUSTS TO 35 MPH WILL BE VERY LIKELY
INTO EARLY AFTERNOON.
BREAKS HAVE DEVELOPED IN THE CLOUD COVER BUT SATELLITE TRENDS ARE
INDICATING THESE ARE FILLING IN. AS THE STRONGER SUBSIDENCE
DEVELOPS BEHIND THE DEPARTING SHORTWAVE THIS AFTERNOON CLOUDS
SHOULD BEGIN TO BREAK UP WITH CLEARING OCCURRING ACROSS MUCH OF
THE AREA BY OR SHORTLY AFTER SUNSET.
TEMPERATURES WILL CONTINUE TO SLOWLY FALL THROUGH THE AFTERNOON.
ANY PEEKS OF SUN MAY RESULT IN A BRIEF RISE IN SOME AREAS.
AN UPDATE REFLECTING ALL THIS WILL BE AVAILABLE SHORTLY.
..08..
&&
.PREV DISCUSSION... /ISSUED 535 AM CST THU DEC 15 2011/
AVIATION...
LOW CLOUDS WITH BASES OF 800-2500 FEET TO PERSIST AT ALL TERMINALS
THROUGH 17Z OR 11 AM RESULTING IN MVFR TO BRIEFLY IFR CONDITIONS
AT DBQ AND CID TERMINALS. LOW CLOUDS TO GRADUALLY BREAK UP BETWEEN
17-23Z OR 11 AM AND 5 PM RESULTING IN VFR CONDITIONS. WEST TO
NORTHWEST WINDS OF 15 TO 30+ MPH TO DIMINISH TOWARD SUNSET TO 5-10
MPH BY 9 PM. CLEAR SKIES WITH LIGHT NW WINDS TO CONTINUE THROUGH
AT LEAST 16/18Z. ..NICHOLS..
PREV DISCUSSION... /ISSUED 330 AM CST THU DEC 15 2011/
SYNOPSIS...
SURFACE ANALYSIS SHOWS STRONG COLD AIR ADVECTION UNDERWAY ACROSS THE
FORECAST AREA FROM WEST TO NORTHWEST WINDS OF 15 TO 25 MPH.
ISALLOBARIC PRESSURE RISES SUPPORT WINDS TO INCREASE TO 20 TO 30+ MPH
WITH ISOLATED GUSTS AROUND 35 MPH UNTIL MID AFTERNOON. LOW CLOUDS TO
COMBINE WITH COLD AIR ARRIVING TO KEEP TEMPERATURES STEADY OR SLOWLY
FALLING ALL DAY. ISOLATED VERY LIGHT DRIZZLE MAY BE POSSIBLE INTO THE
MID MORNING HOURS. UPPER AIR ANALYSIS SUPPORTS SEASONALLY COLD AND
QUIET NEXT SEVERAL DAYS UNDER NORTHWEST FLOW REGIME. ..NICHOLS..
SHORT TERM...TODAY AND TONIGHT...
TODAY...AS DISCUSSED ABOVE...WINDY AND COLD WITH NEAR STEADY TO
SLOWLY FALLING TEMPERATURE ALL DAY FROM W-NW WINDS OF 20 TO 30+ MPH
WITH ISOLATED HIGHER GUSTS TO AROUND 35 MPH ALONG AND NORTH OF I-80
CORRIDOR UNTIL LATE AFTERNOON. LOW CLOUDS TO PERSIST ACROSS THE
REGION INTO EARLY TO MID AFTERNOON WITH RAPID CLEARING OCCURRING IN
LATE AFTERNOON HOURS FROM SUBSIDENCE AND LOSS OF HEATING AS THE SUN
SETS. TEMPERATURES TO HOVER IN THE MID TO UPPER 30S ALL BUT FAR SE
SECTIONS WHICH WILL STAY IN THE LOWER 40S INTO EARLY AFTERNOON AND
THEN FALL INTO THE 30S.
TONIGHT...CLEAR AND COLD WITH NW WINDS DECREASING TO 5 TO 10 MPH TO
ALLOW ENOUGH BL DECOUPLING FOR LOWS OF 20 TO 25 DEGREES WITH LOCAL
TECHNIQUES SUGGESTING UPPER TEENS IN MANY LOCATIONS ACROSS THE NW
SECTIONS FOR LATER SHIFTS TO CONSIDER. ..NICHOLS..
LONG TERM...FRIDAY THROUGH WEDNESDAY...
PERIOD OF NW FLOW ALOFT AND MORE SEASONABLE TEMPERATURES ARE IN
STORE FOR FRIDAY THROUGH SUNDAY. FOCUS THEN TURNS TO A STORM SYSTEM
LIFTING OUT OF THE SOUTHWEST THAT MAY BRING PRECIPITATION TO THE
AREA EARLY NEXT WEEK.
MODELS CONTINUE TO DEPICT A WEAK CLIPPER SYSTEM FOR FRIDAY
NIGHT...WITH LATEST RUNS DEVELOPING A WEAK CIRCULATION AT THE
SURFACE AND VERY LIGHT QPF. THIS WEAK CIRCULATION AND AXIS OF
STRONGEST LIFT PASSES THROUGH THE NORTHERN HALF OF THE FORECAST
THROUGH AROUND 06Z...AND HAVE GONE WITH SLIGHT CHANCES FOR LIGHT
SNOW ACCUMULATION. NON-ACCUMULATING FLURRIES ARE MORE LIKELY...AND
HAVE EXTENDED MENTION OF OVERNIGHT FLURRIES OVER ALL BUT THE
SOUTHWEST.
A STRONGER SHORTWAVE IS SHOWN PASSING TO THE NORTH ON SATURDAY...
WITH ASSOCIATED FLURRIES AND SNOW CHANCES TRENDING WELL TO THE NORTH
AND NOT INCLUDED IN THE FORECAST. TEMPERATURES BOTH FRIDAY AND
SATURDAY SHOULD BE LIMITED TO THE 30S OVER MOST OF THE REGION...WITH
OVERNIGHT LOWS IN THE 20S.
THE LATEST MODEL RUNS HAVE COME INTO BETTER AGREEMENT SHOWING
ANOTHER SHORTWAVE IN THE NORTHERN STREAM PASSING TO THE NORTH SUNDAY
NIGHT THAT SENDS A COLD FRONT THROUGH THE FORECAST AREA SUNDAY NIGHT
OR MONDAY. THIS IS FOLLOWED BY A SURFACE SYSTEM AND UPPER LOW
LIFTING OUT OF THE SOUTHWEST U.S. ALONG THIS COLD FRONT. THE LATEST
GFS AND ECMWF HAVE LATCHED ONTO A TRACK THAT WOULD THIS SYSTEM
MAINLY WELL TO THE SOUTH...SUGGESTING A DRY PERIOD UNDER HIGH
PRESSURE. THE UKMET AND GEM OFFER A MORE NWRLY TRACK THAT WOULD
IMPACT THE AREA. OVERALL...CONFIDENCE REMAINS LOW IN ANY
DETERMINISTIC FORECAST IN THESE PERIODS AS DIFFERENCES IN PHASING OF
SHORTWAVES IN THE NORTHERN STREAM AND THE UPPER LOW EJECTING FROM THE
SOUTHWEST CONTINUE BETWEEN MEDIUM RANGE MODELS WITH POOR RUN TO RUN
CONSISTENCY. THE GFS HAS REMAINED THE MOST CONSISTENT...HOLDING A
TRACK THAT WOULD KEEP THE SYSTEM WELL TO THE SOUTH. FOR NOW...THE
FORECAST HAS BEEN NUDGED TOWARD MORE SOUTHERLY AND SLOWER
SOLUTIONS...RESULTING IN A SLIGHT LOWERING OF POPS FROM SUNDAY NIGHT
THROUGH TUESDAY. PRECIPITATION TYPE IS ALSO A CHALLENGE...AND KEPT
AS A MIX FOR NOW WITH BETTER CHANCES FOR SNOW IN THE NORTH AND RAIN
IN THE SOUTHEAST. WEDNESDAY IS KEPT WITH TEMPERATURES NEAR CLIMO...
BUT IF THE SLOWER TIMING OF THE 00Z ECMWF HOLDS TRUE...PRECIPITATION
CHANCES MAY NEED TO BE EXTENDED TO THIS PERIOD AS WELL. ..SHEETS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1223 PM MST THU DEC 15 2011
.UPDATE...
1222 PM MST THU DEC 15 2011
JUST COMPLETED AN UPDATE. TEMPERATURES HAVE JUST RISEN TO NEAR
FORECAST MAXES. SO RAISED HIGH TEMPERATURES 2 TO 3 DEGREES ACROSS
THE BOARD.
BULLER
&&
.SHORT TERM (TODAY-SATURDAY)...
230 AM MST THU DEC 15 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE POSITIVELY
TILTED TROUGH ACROSS THE CENTRAL US...WITH MEAN AXIS EXTENDING
FROM MINNESOTA ACROSS WESTERN KANSAS TO THE BAJA PENINSULA.
EARLY THIS MORNING...RUC H7 ANALYSIS SHOWS AXIS OF POSITIVE
FRONTOGENESIS EXTENDING ACROSS EXTREME SW PART OF CWA...WHICH
COULD ACT AS A FOCUS FOR DEVELOPMENT OF FLURRIES BEFORE 12Z. WHILE
RADAR SHOWING LIGHT RETURNS SW OF THIS AREA THERE HAVE BEEN NO
REPORTS OF FLURRIES...AND CONSIDERING DRY LAYER IN PLACE BELOW
5000-7000FT WILL LEAVE MENTION OUT OF FORECAST FOR NOW AND
CONTINUE TO MONITOR.
TODAY-SATURDAY...SHORTWAVE RIDGING DEVELOPS OVER WESTERN KANSAS
IN REPOSE TO CUTOFF LOW DEEPENING OVER THE SW US. EXPECTING DRY
CONDITIONS AND A GRADUAL WARMING TREND THROUGH THIS WEEKEND.
SEASONAL TEMPS TODAY AND FRIDAY WILL BE FOLLOWED BY MILDER TEMPS
SATURDAY WHEN AFTERNOON TEMPS AROUND 50 ARE EXPECTED. WARMEST END
OF GUIDANCE FOR SAT WOULD SUPPORT TEMPS IN THE MID 50S.
DR
.LONG TERM (SUNDAY-WEDNESDAY)...
230 AM MST THU DEC 15 2011
A CUTOFF LOW PRESSURE SYSTEM SPINNING OVER BAJA ON SUNDAY WILL
BEGIN TO MOVE INLAND ALONG THE UNITED STATES MEXICO BORDER. THE
GFS KEEPS THE LOW CENTER NEAR THE BORDER AS IT MOVES EAST OF THE
ROCKIES WHILE THE ECMWF TAKES A SLIGHTLY MORE NORTHERLY
TRACK...PUTTING THE UPPER LOW IN THE NORTHERN TEXAS PANHANDLE BY
MONDAY EVENING WHILE THE GFS HAS IT IN THE SOUTHERN PANHANDLE
REGION. THIS DIFFERENCE IN TRACK AS THE LOW MOVES EAST OF THE
ROCKIES WILL MAKE THE DIFFERENCE BETWEEN THE FORECAST AREA
RECEIVING PRECIPITATION OR KEEPING THE FORECAST DRY FOR THE
BEGINNING OF NEXT WEEK. AS THE MODEL SOLUTIONS EVOLVE FROM CUTTING
OFF THE UPPER LOW OVER THE FAR SOUTHWEST UNITED STATES TO
REINCORPORATING IT INTO THE UPPER FLOW THROUGH THE FORECAST
PERIOD...CONFIDENCE IN EITHER PARTICULAR SOLUTION ARE LOW. THE
GENERAL CONSENSUS IS TO GO WITH A SLOWER SOLUTION THAT FAVORS
DELAYING PRECIPITATION ACROSS THE FORECAST AREA UNTIL MONDAY, AND
THEN KEEPING A RAIN SNOW MIX ON MONDAY THAT TRANSITIONS TO LIGHT
SNOW MONDAY NIGHT AND POSSIBLY INTO TUESDAY MORNING AS THE LOW
CONTINUES ACROSS THE SOUTHERN PLAINS AND INTO THE MISSISSIPPI
VALLEY REGION BY LATE TUESDAY.
LOCKHART
&&
.AVIATION...
1040 AM MST THU DEC 15 2011
FOR THE 18Z TAFS...VFR CONDITIONS CONTINUE THROUGH THE EVENING AND
THEN THINGS GET A LITTLE MORE INTERESTING. TO SOME DEGREE ALL THE
MODEL OUTPUT IS SHOWING RETURN FLOW DURING THE NIGHT BRINGING UP
SOME STRATUS...STILL IN VFR...AFTER 06Z. IT IS ALSO POSSIBLE THAT
SOME FOG COULD RESULT AS WELL. CONSIDERING THAT DEWPOINTS ARE
RUNNING A LITTLE HIGHER THAN PROGGED AND MORE IN LINE WITH THE
NAM...PROBABLY DUE TO THE CONTINUED SNOW MELT...ESPECIALLY TO OUR
SOUTH SOUTHWEST...THINKING THAT THIS MAY NOT BE OUT OF THE REALM
OF POSSIBILITY. RIGHT NOW THE FAVORED AREA WOULD BE MORE NEAR
KGLD THAN KMCK. SO AT THIS TIME PUT A LITTLE LOWER CONDITIONS AT
KGLD AND WILL CONTINUE TO MONITOR THE LATEST OBSERVATIONS AND
MODEL TRENDS. WHATEVER OCCURS DOES NOT LAST TOO LONG AFTER 12Z AS
SURFACE TROUGH MOVES AND BRINGS IN STRONGER WEST TO NORTHWEST
WINDS.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1048 AM MST THU DEC 15 2011
.SHORT TERM (TODAY-SATURDAY)...
230 AM MST THU DEC 15 2011
EARLY MORNING WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE POSITIVELY
TILTED TROUGH ACROSS THE CENTRAL US...WITH MEAN AXIS EXTENDING
FROM MINNESOTA ACROSS WESTERN KANSAS TO THE BAJA PENINSULA.
EARLY THIS MORNING...RUC H7 ANALYSIS SHOWS AXIS OF POSITIVE
FRONTOGENESIS EXTENDING ACROSS EXTREME SW PART OF CWA...WHICH
COULD ACT AS A FOCUS FOR DEVELOPMENT OF FLURRIES BEFORE 12Z. WHILE
RADAR SHOWING LIGHT RETURNS SW OF THIS AREA THERE HAVE BEEN NO
REPORTS OF FLURRIES...AND CONSIDERING DRY LAYER IN PLACE BELOW
5000-7000FT WILL LEAVE MENTION OUT OF FORECAST FOR NOW AND
CONTINUE TO MONITOR.
TODAY-SATURDAY...SHORTWAVE RIDGING DEVELOPS OVER WESTERN KANSAS
IN REPOSE TO CUTOFF LOW DEEPENING OVER THE SW US. EXPECTING DRY
CONDITIONS AND A GRADUAL WARMING TREND THROUGH THIS WEEKEND.
SEASONAL TEMPS TODAY AND FRIDAY WILL BE FOLLOWED BY MILDER TEMPS
SATURDAY WHEN AFTERNOON TEMPS AROUND 50 ARE EXPECTED. WARMEST END
OF GUIDANCE FOR SAT WOULD SUPPORT TEMPS IN THE MID 50S.
DR
.LONG TERM (SUNDAY-WEDNESDAY)...
230 AM MST THU DEC 15 2011
A CUTOFF LOW PRESSURE SYSTEM SPINNING OVER BAJA ON SUNDAY WILL
BEGIN TO MOVE INLAND ALONG THE UNITED STATES MEXICO BORDER. THE
GFS KEEPS THE LOW CENTER NEAR THE BORDER AS IT MOVES EAST OF THE
ROCKIES WHILE THE ECMWF TAKES A SLIGHTLY MORE NORTHERLY
TRACK...PUTTING THE UPPER LOW IN THE NORTHERN TEXAS PANHANDLE BY
MONDAY EVENING WHILE THE GFS HAS IT IN THE SOUTHERN PANHANDLE
REGION. THIS DIFFERENCE IN TRACK AS THE LOW MOVES EAST OF THE
ROCKIES WILL MAKE THE DIFFERENCE BETWEEN THE FORECAST AREA
RECEIVING PRECIPITATION OR KEEPING THE FORECAST DRY FOR THE
BEGINNING OF NEXT WEEK. AS THE MODEL SOLUTIONS EVOLVE FROM CUTTING
OFF THE UPPER LOW OVER THE FAR SOUTHWEST UNITED STATES TO
REINCORPORATING IT INTO THE UPPER FLOW THROUGH THE FORECAST
PERIOD...CONFIDENCE IN EITHER PARTICULAR SOLUTION ARE LOW. THE
GENERAL CONSENSUS IS TO GO WITH A SLOWER SOLUTION THAT FAVORS
DELAYING PRECIPITATION ACROSS THE FORECAST AREA UNTIL MONDAY, AND
THEN KEEPING A RAIN SNOW MIX ON MONDAY THAT TRANSITIONS TO LIGHT
SNOW MONDAY NIGHT AND POSSIBLY INTO TUESDAY MORNING AS THE LOW
CONTINUES ACROSS THE SOUTHERN PLAINS AND INTO THE MISSISSIPPI
VALLEY REGION BY LATE TUESDAY.
LOCKHART
&&
.AVIATION...
1040 AM MST THU DEC 15 2011
FOR THE 18Z TAFS...VFR CONDITIONS CONTINUE THROUGH THE EVENING AND
THEN THINGS GET A LITTLE MORE INTERESTING. TO SOME DEGREE ALL THE
MODEL OUTPUT IS SHOWING RETURN FLOW DURING THE NIGHT BRINGING UP
SOME STRATUS...STILL IN VFR...AFTER 06Z. IT IS ALSO POSSIBLE THAT
SOME FOG COULD RESULT AS WELL. CONSIDERING THAT DEWPOINTS ARE
RUNNING A LITTLE HIGHER THAN PROGGED AND MORE IN LINE WITH THE
NAM...PROBABLY DUE TO THE CONTINUED SNOW MELT...ESPECIALLY TO OUR
SOUTH SOUTHWEST...THINKING THAT THIS MAY NOT BE OUT OF THE REALM
OF POSSIBILITY. RIGHT NOW THE FAVORED AREA WOULD BE MORE NEAR
KGLD THAN KMCK. SO AT THIS TIME PUT A LITTLE LOWER CONDITIONS AT
KGLD AND WILL CONTINUE TO MONITOR THE LATEST OBSERVATIONS AND
MODEL TRENDS. WHATEVER OCCURS DOES NOT LAST TOO LONG AFTER 12Z AS
SURFACE TROUGH MOVES AND BRINGS IN STRONGER WEST TO NORTHWEST
WINDS.
BULLER
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
ISSUED BY NATIONAL WEATHER SERVICE CARIBOU ME
1225 PM EST THU DEC 15 2011
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTH OF THE REGION THIS AFTERNOON DRAWING A WARM
FRONT ACROSS THE AREA. A STRONG COLD FRONT WILL APPROACH THE REGION
FROM THE NORTHWEST TONIGHT AND CROSS THE AREA ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
TEMPERATURES ARE WARMING NICELY THROUGH THE 30S INTO THE LOWER
40S. VALLEY AREAS IN WESTERN AREAS OF MAINE STILL HOVERING IN THE
LOWER 30S BUT PRECIP IS IN LIQUID FORM. SNOW/SLEET HAVE ENDED. THE
WSW FOR WESTERN MAINE HAS BEEN ALLOWED TO EXPIRE. LATEST LAPS SOUNDINGS
INDICATE WARMING DOWN TO THE SFC NOW WILL RAIN.ADJUSTED THE POPS
THROUGH THE REST OF THE AFTERNOON USING THE GFS AND RUC AS A START
AND THEN MANUALLY ADJUSTED W/SOME DRY SLOTTING ATTM. ANOTHER BATCH
OF RAIN MOVING THROUGH SOUTHERN QUEBEC WILL MOVE ACROSS THE REGION
LATER THIS AFTERNOON INTO THE EVENING. WINDS HAVE BEEN GUSTING TO
35 MPH AT PWM AND PSM.
.PREVIOUS DISCUSSION...
MODELS IN VERY GOOD AGREEMENT WITH WARM FRONT CROSSING THE REGION
TODAY. SOUTHERLY FLOW HAS ALLOWED TEMPERATURES TO WARM THROUGH THE
NIGHT WITH READINGS ABOVE FREEZING ACROSS MOST OF SOUTHERN AND
CENTRAL NEW HAMPSHIRE SO HAVE DECIDED TO DROP THE ADVISORY THERE
FOR THIS MORNING. CRITICAL THICKNESS INDICATES MAINLY SLEET AND
FREEZING RAIN ACROSS THE REMINDER OF THE ADVISORY AREA THIS
MORNING BEFORE PRECIP CHANGES TO ALL RAIN BEFORE NOONTIME. AT THIS
TIME, EXPECT ANY SNOW/SLEET ACCUMULATION TO BE LESS THAN AN INCH
AND ANY ICING A TENTH OF AN INCH OR LESS. EXPECT MAIN AREA OF
PRECIP TO MOVE EAST OF THE AREA DURING THIS AFTERNOON WITH ONLY
SCATTERED RAIN SHOWERS FOR TONIGHT. STRONG LOW LEVEL JET WILL MOVE
ACROSS COASTAL SECTIONS ESPECIALLY OVER LINCOLN, KNOX AND WALDO COUNTIES
WHERE WINDS WILL GUSTS UP TO 40 MPH LATER THIS AFTERNOON INTO
EARLY THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
STRONG COLD FRONT WILL CROSS THE REGION FRIDAY UNDER A STRONG
NORTHWEST WIND. STRONG COLD AIR ADVECTION ALONG WITH UPSLOPE WILL
PRODUCE SNOW SHOWERS ACROSS THE MOUNTAINS OF NEW HAMPSHIRE AND
MAINE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE REGION SATURDAY AND
SUNDAY AND CREST THE AREA SUNDAY EVENING. QUICK MOVING LOW
PRESSURE MAY PROVIDE SOME LIGHT SNOW ACROSS NORTHERN NH AND MAINE
ON MONDAY WITH HIGH PRESSURE BUILDING ACROSS THE REGION ON
TUESDAY. STILL A LOT OF UNCERTAINTY FOR THE END OF THE WEEK AS LOW
PRESSURE AFFECTS THE REGION.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...MVFR/IFR CONDITIONS INTO TONIGHT.
LONG TERM... VFR CONDITIONS FRIDAY THROUGH SATURDAY. GUSTY NORTHWEST
WINDS ON FRIDAY AS STRONG COLD FRONT CROSSES THE REGION.
&&
.MARINE...
SHORT TERM...STRONG LOW LEVEL JET WILL MOVE ACROSS THE GULF OF
MAINE TODAY PRODUCING GALE FORCE WINDS FOR THE EASTERN HALF OF OUR
WATERS. WINDS NOT AS STRONG OVER WESTERN SECTIONS WHERE SCA
CONDITIONS WILL PREVAIL.
LONG TERM...AS STRONG COLD FRONT CROSSES THE WATER, GALE CONDITIONS
POSSIBLE AGAIN ON FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ153-154.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR ANZ150>152.
&&
$$
SYNOPSIS...HEWITT
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
525 PM EST THU DEC 15 2011
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS EVENING WITH SHOWERS AND
GUSTY WIND. COLDER AIR BEHIND THE FRONT WILL BRING A FEW SNOW SHOWERS
TO THE RIDGES AND NORTHWEST PENNSYLVANIA LATER TONIGHT. DRY AND
SEASONABLE FRIDAY FOLLOWED BY SCATTERED SNOW SHOWERS SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
UPDATE WAS MADE EARLIER TO UP WIND GUSTS TO 30-35 MPH WITH COLD
FRONTAL PASSAGE.
COLD FRONT CHUGGING ALONG INTO CENTRAL OHIO BY 20Z WITH A BAND OF
SHOWERS ALONG FRONT AND SCATTERED SHOWERS AHEAD OF IT. AFTER FRONT
PASSES TEMPERATURES WILL GRADUALLY FALL OVERNIGHT WITH NORTHWEST
FLOW ACROSS LAKES BRINGING A BRIEF PERIOD OF SNOW SHOWERS LATER
TONIGHT INTO EARLY FRIDAY. WHILE 850MB TEMPERATURES WILL BE NEAR
-8 C BY DAYBREAK INVERSION HEIGHTS WILL BE LOW AND LOWERING WITH A
LACK OF DEEP MOISTURE. SO LITTLE IF ANY ACCUMULATION.
AS DAY GOES ON FRIDAY, HIGH PRESSURE WILL WORK INTO REGION WITH
NEAR NORMAL TEMPS AND A MIX OF CLOUDS AND SUNSHINE. TIGHT SFC
PRESS GRADIENT WILL KEEP WINDS GUSTY FIRST HAVE OF TONIGHT WITH
FROPA THEN DIMINISHING AFTER MIDNIGHT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A FAST MOVING SHORTWAVE AND LOW PRESSURE CENTER MOVING ALONG MID
ATLANTIC FRIDAY NIGHT INTO EARLY SATURDAY WILL SPREAD CLOUDS INTO
THE SOUTHEAST RIDGES BUT APPEARS PRECIP WILL REMAIN SOUTH.
AS FOR THE REST OF THE AREA, HIGH PRESSURE WILL ALLOW FOR DRY
WEATHER FRIDAY NIGHT BEFORE A SHORT WAVE TROUGH WILL BEGIN TO DIVE
FROM THE GREAT LAKES SOUTHEASTWARD INTO THE AREA. THIS WILL RETURN
THE CHANCE OF SNOW SHOWERS, ESPECIALLY NORTH OF PITTSBURGH
SATURDAY MORNING, SPREADING SOUTH ACROSS THE REGION BY THE
EVENING. 850MB TEMPERATURES PROGGED TO FALL TO -10 C DURING DAY
AND THIS WILL COMBINE WITH SHORTWAVE TO BRING LIGHT ACCUMULATIONS
TO THE RIDGES AND I-80 CORRIDOR SATURDAY NIGHT TO EARLY SUNDAY.
TEMPERATURES WILL BE NEAR NORMAL TO A BIT BELOW.
ON SUNDAY LOWER AND MID LEVEL FLOW WILL BEGIN TO TURN WESTERLY
AND SNOW SHOWERS WILL DIMINISH WITH TEMPERATURES AGAIN AROUND
NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE MODELS SHOW CLOSED UPPER LOW OVER THE SOUTHERN PLAINS
MONDAY...GRADUALLY WEAKENING AS IT TRACKS NORTHEAST THROUGH MIDWEEK.
ASSOCIATED SURFACE LOW IS FORECAST TO TRACK FROM THE SOUTHERN PLAINS
INTO THE MID MS VALLEY BY WEDNESDAY...AND OFF THE MID ATLANTIC COAST
THURSDAY.
WENT CLOSE TO HPC GUIDANCE KEEPING THE FORECAST AREA DRY (POPS LESS
THAN 25 PERCENT) THROUGH LATE MONDAY...THEN CHANCE POPS TUESDAY AND
WEDNESDAY. LIMITED SCATTERED SHOWERS TO EASTERN SECTIONS THURSDAY AS
SYSTEM EXITS.
TEMPERATURES ARE FORECAST TO RANGE FROM 5 TO 10 DEGREES ABOVE NORMAL
THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
PER RECENT SURFACE AND RADAR DATA PLUS HRRR AND NAM MODEL OUTPUT,
EXPECT COLD FRONTAL BAND OF SHOWERS TO PRODUCE BRIEF IFR CONDITIONS
AND WIND GUSTS TO ABOUT 30 KTS.
FRONTAL SHOWERS WILL MOVE PAST KMGW AND KLBE BY 00Z. POST FRONTAL
DRYING WILL PROMOTE MAINLY MVFR STRATOCUMULUS OVERNIGHT INTO MIDDAY
FRIDAY. NAM MODEL PROFILES SUGGEST WESTERLY WINDS CAN STILL GUST TO
30 KTS AT TIMES UNTIL 08Z-12Z.
OUTLOOK... FRIDAY NIGHT THROUGH TUESDAY...
SURFACE RIDGE SHOULD PROVIDE GENERALLY VFR CONDITIONS FRIDAY NIGHT
INTO EARLY SATURDAY. A SHORT WAVE TROUGH AND ASSOCIATED WEAK SURFACE
FRONT MOVING ACROSS THE GREAT LAKES WILL BRING SCATTERED SNOW
SHOWERS AND THE POTENTIAL FOR RESTRICTIONS SATURDAY AFTERNOON INTO
SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
340 PM EST THU DEC 15 2011
LATEST UPDATE...ALL EXCEPT AVIATION...
.SYNOPSIS...(340 PM EST THU DEC 15 2011)
A COLDER AIRMASS CONTINUES TO FILTER INTO SOUTHWEST LOWER MICHIGAN
IN THE WAKE OF A THURSDAY MORNING COLD FRONTAL PASSAGE. WEST TO
NORTHWEST WINDS WILL DROP LOWS INTO THE 20S IN MOST LOCATIONS
TONIGHT. IT WILL BE WINDY THIS EVENING BEFORE WINDS SUBSIDE
CONSIDERABLY OVERNIGHT. LAKE EFFECT SNOW SHOWERS ARE EXPECTED THIS
EVENING AND AGAIN FRIDAY NIGHT INTO SATURDAY. ACCUMULATIONS WILL BE
LIGHT TONIGHT ON THE ORDER OF A DUSTING TO POSSIBLY A HALF INCH IN A
FEW SPOTS. LOCALIZED ACCUMULATIONS FRIDAY NIGHT INTO SATURDAY MAY
REACH AN INCH OR TWO...BUT MOST LOCATIONS WILL SEE VERY LITTLE
ACCUMULATION. EVEN WITH THE COOL DOWN...TEMPERATURES WILL REMAIN
SLIGHTLY ABOVE NORMAL INTO THE WEEKEND.
&&
.SHORT TERM...(340 PM EST THU DEC 15 2011)
(TONIGHT THROUGH SATURDAY NIGHT)
MAIN FOCUS OF THE SHORT TERM REVOLVES AROUND THE WIND THIS EVENING
AND THEN CHANCES FOR LAKE EFFECT SNOW THROUGH THE PERIOD.
MAINTAINED THE WIND ADVISORY WITH THE CORE OF THE WIND STILL SET TO
COME THROUGH. MAIN CONCERN ARE A FEW GUSTS INTO THE 45 TO 50 MPH
RANGE BETWEEN 400 PM AND 1000 PM OR SO. LOCATIONS NEAR LAKE MICHIGAN
STAND THE BEST CHANCE OF SEEING GUSTS TO THIS SPEED. THE WIND SHOULD
GRADUALLY SUBSIDE FROM MIDNIGHT INTO FRIDAY MORNING.
AS FOR LAKE EFFECT SNOW CHANCES...THERE ARE TWO TIME FRAMES OF
POTENTIAL. THE FIRST BEING THIS EVENING...WHERE DEEPER MOISTURE
INTERACTS WITH INCREASING INSTABILITY. THE DEEPER MOISTURE IS ONLY
IN PLACE THROUGH THE 03Z TO 06Z TIME FRAME THOUGH AFTER WHICH TIME
IT DWINDLES TO 4000-5000FT OR LESS. THIS EVENING...EXPECT SNOW
SHOWER ACTIVITY WITH LIGHT ACCUMULATIONS (INCH OR LESS) ACROSS
CENTRAL LOWER MICHIGAN AND POSSIBLY ALONG THE HIGHWAY 131 CORRIDOR
(GIVEN THE STIFF WESTERLY WINDS DISPLACING BANDS INLAND A BIT). A
WET WARM GROUND WILL COUNTERACT THE SNOW SHOWERS SOME.
RELATIVE HUMIDITY IS QUITE LACKING IN THE OVERNIGHT THROUGH FRIDAY
EVENING TIME FRAME AND THEREFORE NOT EXPECTING MUCH IN THE WAY OF
SNOW SHOWERS DESPITE DELTA T/S IN THE MIDDLE TEENS C.
A COUPLE OF SHORTWAVE TROUGHS ROTATE THROUGH THE REGION FRIDAY NIGHT
INTO SATURDAY WHICH SHOULD GIVE A BOOST TO LAKE EFFECT CLOUDS AND
SNOW SHOWERS. SOME MINOR ACCUMULATIONS ARE POSSIBLE ALONG AND WEST
OF HIGHWAY 131. ENVISION DUSTING TO HALF INCH ACCUMS IN MOST
AREAS...BUT SOME LOCALIZED ACCUMS OF AN INCH OR TWO WILL BE
POSSIBLE.
&&
.LONG TERM...(340 PM EST THU DEC 15 2011)
(SUNDAY THROUGH THURSDAY)
SUNDAY LOOKS DRY AS A SFC HIGH AND NW FLOW ALOFT PRODUCES SOME
SUNSHINE ACROSS THE GREAT LAKES.
MODELS CONTINUE TO BE ON DIFFERENT PAGES WRT THE SRN STREAM LOW
MONDAY AND TUESDAY. BOTH THE ECMWF/GFS SHOW A SRN STREAM SHORT WAVE
BEING KICKED NEWD BY A NRN STREAM WAVE. THE ECMWF HOWEVER TAKES THE
LOW MORE EWD THROUGH THE OHIO VALLEY VS THE GFS THAT TAKES THE LOW
OVER LWR MI. BASED ON THE UPPER WAVE TRACK I TEND TO BUY THE GFS
TRACK MORE. THIS TRACK WOULD ALSO BRING WARMER AIR INTO THE CWA.
THUS WE/LL KEEP THE RAIN/SNOW MIX MON-TUE NIGHT. LIGHT SNOW POSSIBLE
ON THE BACK SIDE OF THE SYSTEM WEDNESDAY AS H8 TEMPS FALL TO -5C IN
NW FLOW. TEMPS WILL CONTINUE TO BE A FEW DEGREES WARMER THAN NORMAL
THROUGH THE PERIOD.
&&
.AVIATION...(106 PM EST THU DEC 15 2011)
MVFR CIGS COVER A LARGE PORTION OF THE GREAT LAKES. THE EXCEPTION IS
THE FAR SW LAKE SHORE SOUTH OF SOUTH HAVEN WHERE VFR CIGS ARE
OBSERVED. IT/S POSSIBLE THAT SOME VFR COULD SNEAK INTO
KAZO...HOWEVER MVFR CIGS EXPECTED THROUGH THE AFTERNOON/EVE.
&&
.MARINE...(340 PM EST THU DEC 15 2011)
WILL MAINTAIN THE GALE WARNING THROUGH THIS EVENING AS THE CORE OF
THE WIND LOOKS TO COME THROUGH BETWEEN 400PM AND 1000PM. WE WILL
EXTEND THE GALE SLIGHTLY TO GIVE A LITTLE BIT OF A BUFFER ON THE
BACK END...THROUGH 100 AM. RUC OVERVIEW/S ALONG THE
COAST ARE SHOWING 40 KNOTS OF WIND DOWN TO AROUND 1000FT...WHICH
SHOULD TRANSLATE INTO FREQUENT GALE FORCE GUSTS AT THE COASTAL
SITES. WINDS WILL DROP BELOW GALE FORCE AFTER MIDNIGHT AND WE WILL
NEED A SMALL CRAFT ADVISORY THAT WILL STRETCH INTO THE DAYLIGHT
HOURS OF FRIDAY. SUB SMALL CRAFT ADVISORIES CONDITIONS ARE EXPECTED
FROM FRIDAY EVENING INTO SUNDAY.
&&
.HYDROLOGY...(340 PM EST THU DEC 15 2011)
ONE RIVER FLOOD WARNING (VICKSBURG) AND THREE RIVER FLOOD ADVISORIES
(IONIA...BURLINGTON AND HOLT) ARE CURRENTLY IN EFFECT. WE ARE NOT
EXPECTING MUCH IN THE WAY OF CHANGES TO RIVER HEADLINES AT THIS
POINT GIVEN THE RAINFALL HAS OCCURRED AND IS MAKING IT/S WAY INTO
THE RIVERS. RAINFALL TOTALS RANGED FROM A HALF INCH TO SLIGHTLY OVER
ONE INCH FOR THE LAST 24 HOURS OR SO. COLDER AIR IS NOW SURGING INTO
THE AREA AND THIS WILL ACT TO SLIGHTLY SUPPRESS RUN OFF SLIGHTLY.
SO...BOTTOM LINE RISES WILL CONTINUE THE NEXT COUPLE OF DAYS WITH
MOST SITES IN THE AREA REMAINING UNDER BANKFULL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY LAKESHORE COUNTIES THROUGH 1100 PM.
LM...GALE WARNING ENTIRE NEARSHORE AREA THROUGH 100 AM.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: 93
AVIATION: 93
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1159 AM CST THU DEC 15 2011
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
STILL PLENTY OF WEATHER GOING ON. COLD ADVECTION TAKING SOME TIME
GETTING INTO EASTERN MN AND WESTERN WISCONSIN WITH THE FREEZING
LEVEL STILL IN THE 1500-2000 RANGE BUT DROPPING. WILL STILL NEED TO
KEEP THE POSSIBILITY OF DRIZZLE IN WI AND FREEZING DRIZZLE A
LITTLE FARTHER WEST. THE WAVE BRINGING IN THE COLDER AIR IS OVER
WESTERN LAKE SUPERIOR BUT A STRONGER WAVE IS DROPPING SOUTHEAST
TOWARD LAKE OF THE WOODS. THIS WILL BRING SCATTERED SNOW SHOWERS
TO MAINLY THE EASTERN PARTS OF OF THE CWA INTO THE AFTERNOON...BUT
SOME FLURRIES FOR WESTERN AREA AS WELL THIS MORNING. OF COURSE
LOTS OF CLOUD COVER UPSTREAM IN THE COLD ADVECTION PATTERN AND
THE RUC AND THE LOCAL 4KM MODEL HAVE A BETTER HANDLE ON KEEPING
CLOUDS IN MOST OF THE DAY. SINKING BEHIND THE STRONGER WAVE
ENTERING NORTHERN MN MAY PUNCH SOME HOLES IN THE CLOUD DECK OVER
EASTERN ND AND WESTERN MN LATE AFTERNOON BUT STILL MOSTLY CLOUDY
OVERALL. TEMPS WILL BE FALLING OVER EASTERN AREAS THIS MORNING
AND THEN STEADY OR JUST UP A FEW DEGREES IN THE WEST TODAY.
SEEM TO BE DECENT CONTINUITY WITH THE CLIPPER TYPE SYSTEM IN THE
NORTHERN BRANCH FOR FRIDAY. THE GFS AND NAM SIMILAR WITH SOME
DECENT LIFT IN THE -15C AREA AS THE WAVE MOVES INTO THE AREA. THE
SREF HAS BEEN TRENDING HIGHER IN DEPICTING A DENDRITIC GROWTH
ZONES AS WELL. WILL RAISE POPS MORE INTO THE CHANCE CATEGORY
ACROSS A NW TO SE CORRIDOR THROUGH THE CWA.
THE MILDER TREND IS STILL ON TRACK FOR THE WEEKEND BUT A BIT
DELAYED FOR SATURDAY. MORE OF A SOUTHWEST FLOW SETTING UP FOR
SUNDAY. THE SUNDAY TIME FRAME IS ALSO SIMILAR TO THE TIMING OF THE
THE MAX 850 MB TEMP ANOMALY SHOWN BY THE GEFS. IT IS AMAZING THAT
THE NAEFS FORECAST HAS BEEN SHOWING ABOVE NORMAL TEMPERATURES FOR
WELL OVER A MONTH ACROSS CANADA..THE UPPER MIDWEST...AND GREAT
LAKES...AND CONTINUES WITH THIS TREND WITH THE LATEST RUN OUT TO
DEC 28.
MOST OF THE PRECIP ACTION LOOKS TO BE MAINLY SOUTH OF US IN THE
SPLIT FLOW INTO THE EARLY PART OF THE WEEK..BUT STILL SOMETHING TO
WATCH.
&&
.AVIATION.../18Z TAF ISSUANCE/
CAA AND CYCLONIC FLOW CONSPIRING TO KEEP 020-040 STRATUS LOCKED IN
ACROSS THE AREA. HOWEVER...A NICE DRYING PUSH IS BEGINNING TO WORK
IN FROM THE RED RIVER VALLEY. IN ADDITION STARTING TO SEE MORE
NUMEROUS/LARGER HOLES GETTING PUNCHED IN TO THE STRATUS DECK...SO
GENERALLY KEPT EXISTING TIMING TREND GOING IN TAFS...AS THIS
MATCHES UP WELL WITH CURRENT 925-850MB RH FORECASTS FROM THE
RUC/NAM/GFS. WILL GET A SHORT-LIVED BREAK FROM CLOUDS THIS
EVENING...BEFORE CLOUDS THICKEN/LOWER AGAIN TONIGHT AHEAD OF A
WEAK CLIPPER. SREF PROBS ALONG WITH GFSLAMP FORECASTS BRING MVFR
CIGS BACK TO MOST LOCATIONS BY LATE MORNING/EARLY AFTERNOON
FRIDAY...BUT KEPT THINGS VFR FOR NOW UNTIL WE SEE HOW CIGS START
PLAYING OUT TONIGHT OVER ERN MT. THERE WILL ALSO BE THE POSSIBILITY
OF SNOW...BUT WITH SFC PRESSURE VALUES AROUND 1030MB...WILL
PROBABLY BE TOUGH TO GET MUCH MORE THAN FLURRIES OUT OF ANY
ACTIVITY FRIDAY. FINAL ISSUE THIS TAF ARE THE WINDS. CAA ALONG
WITH SINKING MOTION BEHIND UPPER WAVE MOVING INTO WI HAS RESULTED
IN NUMEROUS AIRPORTS WEST OF I-35 GUSTING UP OVER 30 KTS. SHOULD
CONTINUE TO SEE GUSTY WINDS THROUGH ABOUT 00Z...BUT AFTER THAT
GRADIENT SLACKENS CONSIDERABLY...WITH MOST OF FRIDAY LIKELY TO
HAVE LGT AND VRB WINDS.
KMSP...STARTING TO SEE BREAKS SHOW UP IN THE OVERCAST THE LAST
COUPLE OF HOURS...SO STUCK WITH A SCATTERING OUT AT 23Z...THOUGH
THE VFR CIGS COULD HANG AROUND UNTIL CLOSER TO 03Z. ALSO EXPECT
WINDS TO DIE DOWN QUICKLY AROUND 00Z AS GRADIENT SLACKENS. TOYED
AROUND WITH THE IDEA OF ADDING SOME -SN 20Z-00Z FRIDAY...BUT GIVEN
DRY STATE OF ATMO AND WEAK/BRIEF FORCING...OPTED OUT OF DOING THAT
FOR NOW. IN ADDITION...SREF PROBS FOR MVFR CIGS FRIDAY AFTERNOON
UP AROUND 90 PERCENT...SO CURRENT SCT020 MAY END UP BEING A
CIG...BUT WE HAVE PLENTY OF TIME TO SEE HOW THINGS PLAY OUT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1135 AM CST THU DEC 15 2011
.UPDATE...
SEE AVIATION DISCUSSION BELOW FOR 18Z TAFS.
SATELLITE STARTING TO SHOW SOME BREAKS IN THE STRATUS CLOUD DECK
ACROSS THE CWA THIS MORNING. THUS...ADJUSTED CLOUD COVER A LITTLE
THROUGH THE AFTERNOON. BREEZY/WINDY CONDITIONS WILL CONTINUE INTO
THE AFTERNOON ESPECIALLY EAST IN THE CWA. ADJUSTED TEMPERATURES
AND WINDS A LITTLE FOR THE REST OF THE DAY.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN ABUNDANCE OF STRATUS CLOUDS CONTINUE TO MOVE SOUTHEAST ACROSS
THE DAKOTAS...WITH THE EXTENT OF IT PUSHING WELL NORTH BACK INTO
SOUTHERN CANADA. WESTERN EDGE OF CLOUDS ACROSS SOUTH DAKOTA LIES
ALONG THE MISSOURI RIVER. ALTHOUGH...WITH A SOUTHEAST MOVEMENT TO
THE CLOUDS AND PLENTY LEFT UPSTREAM...EXPECTING THE EASTERN CWA TO
REMAIN IN CLOUDS MOST OF THE DAY. THE WESTERN CWA WILL LIKELY SEE
A BIT MORE SUNSHINE TODAY. MOST MODELS HAVING A HARD TIME PICKING
UP ON THE CLOUD COVER BUT THE RUC13 850 RH SEEMS TO HAVE A BETTER
HANDLE ON THINGS. IT WOULD SUGGEST CLOUD COVER THROUGH THE
AFTERNOON ACROSS THE EASTERN CWA...WITH THE WESTERN CWA IN MORE
SUNSHINE...AS PREVIOUSLY STATED. HAVE ALSO BEEN SEEING SCT
FLURRIES WITH THE STRATUS CLOUDS. PLENTY OF THAT UPSTREAM AS WELL
WITH KBIS AND KMBX RADARS SHOWING FLURRIES. EVEN OBS IN SOUTHERN
CANADA SHOWING -SN FROM TIME TO TIME. HAVE THEREFORE ADDED SCT
FLURRIES TO FORECAST THROUGH 18Z AND COULD BE A SITUATION WHERE IT
MAY NEED TO BE EXTENDED FURTHER INTO THE AFTERNOON ACROSS THE
EASTERN CWA WHEREVER STRATUS CLOUDS HANG ON THE LONGEST.
AGAIN...PLENTY OF ACTIVITY NOTED WELL UPSTREAM INTO SOUTHERN
CANADA. NORTHWEST WINDS WILL REMAIN BREEZY TODAY AS THE PRESSURE
GRADIENT REMAINS FAIRLY TIGHT WITH HIGH PRESSURE BUILDING IN.
HIGHEST SPEEDS WILL BE ACROSS THE EASTERN CWA WITH A DROP OFF IN
WINDS ACROSS THE WESTERN COUNTIES BY THIS AFTERNOON.
SFC HIGH WILL SETTLE IN OVER THE AREA TONIGHT BRINGING LIGHT
WINDS. NEXT ITEM TO WATCH WILL BE THE WEAK SHORTWAVE CROSSING THE
DAKOTAS LATE TONIGHT AND FRIDAY. MODELS STILL PEGGING MOST OF
THE LIGHT SNOWFALL ACROSS ND BUT THERE HAS BEEN A SLIGHT SHIFT
FURTHER SOUTH INTO NORTHERN SD. COUPLE MODELS BRINGING LIGHT QPF
INTO THE NORTHEASTERN COUNTIES AND SREF PROBS FOR .01 SHOWING
DECENT CHANCES ACROSS THE NORTHEASTERN CWA AS WELL. HAVE THEREFORE
INCREASED POPS SLIGHTLY FOR FRIDAY.
FOCUS WILL THEN SHIFT TO THE DEGREE OF WARMTH ON SATURDAY AS MILD
PACIFIC AIR BEGINS TO STREAM ACROSS THE NORTHERN PLAINS. WARM
FRONT CROSSES THE AREA DURING THE DAY SATURDAY WITH WINDS TURNING
WESTERLY. 850 MB TEMPS RISE TO JUST ABOVE ZERO C. WITH THE WIND
SHIFT AND A DECENT AMOUNT OF SUN...WILL SEE TEMPS RISE INTO THE
30S AND 40S.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
NOT MUCH TO TALK ABOUT IN THE EXTENDED FORECAST. CONSENSUS MODELS
ARE STILL GOING WITH CONTINUED DRY CONDITIONS. INTERESTINGLY THE
GFS IS STARTING TO HINT AT THE POSSIBILITY OF SOME PRECIP AT THE
END OF THE FORECAST PERIOD ASSOCIATED WITH THE NEXT UPPER TROF
THAT DIGS INTO THE PLAINS SO WILL NEED TO KEEP AN EYE ON HOW THAT
SYSTEM DEVELOPS. FOR NOW THOUGH LEFT THE FORECAST PRECIP FREE.
WITH THE LACK OF SNOW ON THE GROUND TEMPERATURES WILL ALSO
CONTINUE THE ABOVE NORMAL TREND WITH HIGHS STAYING NEAR 30 OR EVEN
CLIMBING INTO THE 40S THROUGH THE PERIOD.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
BAND OF STRATUS HAS BEEN PERSISTENT...ESPECIALLY ACROSS THE ABR
AND ATY TERMINALS HOWEVER THE WESTERN CLOUD EDGE HAS ERODED NICELY
TOWARDS PIR. STRATUS HAS BEEN PERSISTENT NEAR MBG TERMINAL BUT
BELIEVE CEILINGS WILL BEGIN TO LIFT FURTHER AS THE DAY PROGRESSES.
WINDS WILL GRADUALLY DIMINISH FROM WEST TO EAST TODAY AS A
SHORTWAVE RIDGE PROGRESSES ACROSS THE UPPER MIDWEST. EXPECT WINDS
TO GO LIGHT AND VARIABLE FOR A FEW HOURS AS THE SURFACE RIDGE
PASSES OVER THE REGION THIS EVENING INTO TONIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...TVT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1037 AM CST THU DEC 15 2011
.DISCUSSION.../ISSUED AT 1037 AM CST/
JUST SENT OUT A FRESHENED UP ZFP AND GRIDS. CLOUD COVER IS THE MOST
PROBLEMATIC ELEMENT FOR THIS AFTERNOON. NAM...RUC AND ECMWF LOW
LEVEL MOISTURE FIELDS HAVE NO CLUE THAT STRATUS EXISTS IN OUR
FORECAST AREA. THE GFS...SLIGHTLY BETTER ON CURRENT CONDITIONS...
LIKELY ERODES THE CLOUDS TOO FAST IN OUR EASTERN ZONES. SO STRATUS
EROSION IS REALLY A CHALLENGE. LATEST SATELLITE DOES FINALLY SHOW
SOME EROSION OF STRATUS ON THE WESTERN EDGE NEAR MITCHELL SD. THERE
ARE ALSO SOME AREAS OF CLEARING NOTED IN EASTERN ND. THE STRATUS IS
FAIRLY THIN...SO IT IS POSSIBLE THAT SUBSIDENCE MAY RIP IT APART AS
THE DAY PROGRESSES. IF IT DOES NOT...THEN THE STRATUS WILL LIKELY
HANG TOUGH THROUGH THE DAY EAST OF THE JAMES RIVER. FOR NOW...OPTED
FOR A GRADUAL CLEARING WEST OF I 29...BUT MOSTLY CLOUDY THROUGHOUT
OUR EASTERN ZONES. THE WINDS OFF THE SURFACE SHIFT MORE TO A SW
DIRECTION TONIGHT SO THEY SHOULD EVENTUALLY MOVE OUT OF HERE. CLOUDS
OR NOT...TEMPERATURES WILL NOT MOVE MUCH TODAY OFF OF CURRENT
READINGS DUE TO PLENTY OF COLD AIR ADVECTION. WENT AHEAD AND LET THE
FLURRIES EXPIRE IN OUR NORTHEAST ZONES AS IT LOOKS LIKE MOST OF THE
ACTIVITY SHOULD STAY TO OUR NORTH ALONG THE LEFT EXIT REGION OF A
WEST TO EAST MOVING JET STREAK. PLENTY OF MID LEVEL PV EXISTS
THROUGH 18Z...BUT THEN QUICKLY EXITS THIS AREA. /MJF
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
THERE WILL LIKELY BE A VERY SLOW EROSION OF LOWER VFR TO UPPER END
MVFR CEILINGS THROUGH THE DAY. THAT SAID...IT MAY TAKE QUITE A WHILE
TO GET RID OF THE CLOUD COVER ALONG AND EAST OF I 29. THE TOTAL
EROSION OF LOW CLOUD COVER MAY HAVE TO WAIT UNTIL TONIGHT WHEN THE
WINDS OFF THE SURFACE SHIFT FROM A NW...TO MORE OF A SW DIRECTION
WHERE IT IS CLEAR IN CENTRAL AND WESTERN NEBRASKA. OVERALL...WE
SHOULD HAVE VFR CONDITIONS ACROSS THIS FORECAST AREA FROM 06Z
TONIGHT THROUGH FRIDAY MORNING. SURFACE WIND GUSTS AVERAGING 25 TO
32 KNOTS WILL BE PREVALENT EAST OF THE JAMES RIVER VALLEY UNTIL
ABOUT 22Z THIS AFTERNOON. /MJF
&&
.PREV DISCUSSION...
STRONG NORTHERN STREAM WAVE WILL DELIVER AT LEAST A TEMPORARY RETURN
TOWARD MORE TYPICAL MID DECEMBER WEATHER ACROSS THE AREA TODAY.
MASSIVE STRATUS FIELD IN WAKE OF LEADING WAVE LIFTING TOWARD
NORTHERN WISCONSIN...AS WELL AS GOOD DOSE OF 25 TO 35 MPH NORTHWEST
WINDS. WITH CLOUDS...TEMPERATURES HAVE BEEN MORE SLUGGISH TO FALL
AS HAVE BEEN EQUALIZING WITH MIXING...BUT COLD AIR ADVECTION WILL
SOON BEGIN TO GET THE UPPER HAND...LIKELY KEEPING A DOWNWARD TREND
GOING WELL INTO THE MORNING BEFORE SOME DIURNAL RECOVERY. CLOUDS
WILL HAVE A LOT TO SAY ABOUT THIS...AND HAVE LITTLE OPTION THAN TO
BE EVEN MORE PESSIMISTIC GIVEN TRAJECTORY OF LOW LEVEL FLOW AND
THE CURRENT STRATUS FIELD. FOLLOWED CLOSER TO THE RUC AND FRIENDS
RELATIVE HUMIDITY FIELDS WHICH SEEMED TO HAVE AT LEAST A CLUE WHERE
STRATUS FIELD CURRENTLY RESIDES. OTHER ISSUE THAT HAS BEEN OCCURRING
OVERNIGHT HAS BEEN A FEW FLURRIES. THESE SEEM TO BE MOST CONCENTRATED
IN SMALLER AREAS WITHIN STRATUS FIELD WHERE CLOUD TOPS ARE JUST A
BIT COOLER THAN THE SURROUNDINGS...VERY EVIDENT WITH INITIAL AREA
MOVING THROUGH NORTHWEST IOWA AT 09Z...AND THEN SECONDARY AREA
UP ACROSS NORTHEAST SOUTH DAKOTA. WITH CLOUDS LAYER SNEAKING INTO
THE WARMER END OF THE DENDRITIC LAYER...WOULD NOT BE SURPRISED TO
GET CONTINUATION OF FLURRIES AT TIMES THROUGH AT LEAST MID TO LATE
MORNING WHEN SOME LIFT SUPPORT FROM NORTHERN STREAM UPPER WAVE.
MAY FINALLY GET TO SEE A MORE RAPID EROSION/ADVECTION OF THE CLOUD
BOUNDARY BY THE AFTERNOON AS CONTINUED DRIER LOW LEVEL AIR WORKS ON
CLOUDS FROM BOTTOM UP...AND SUBSIDENCE TO THE SOUTHWEST FLANK OF
UPPER WAVE WORKS FROM THE TOP. WINDS STRONGEST THROUGH THE EARLY
AFTERNOON HOURS...DIMINISHING FROM WEST WITH APPROACH OF RIDGE
AXIS...BUT HANGING ON A BIT STRONGER THROUGH ELEVATED SOUTHWEST
MINNESOTA AREAS WITH DEEPENING SYSTEM TO EAST AND MORE PERSISTENT
COLD AIR ADVECTION.
TONIGHT...CHILLY RIDGE WILL DRIFT EAST ACROSS THE AREA. WILL START
TO GET SOME RETURN FLOW STRENGTHENING A TOUCH FROM THE JAMES VALLEY
WESTWARD...AND THAT ALONG WITH THE THICKENING MID AND HIGH CLOUDS
WILL LIKELY BRING A NON DIURNAL TREND TO LOWS WEST...WITH MORE
TYPICAL FALLS UNDER LINGERING RIDGE THROUGH SOUTHEASTERN AREAS.
NORTHERN PORTION OF TROUGH DIGGING INTO THE SOUTHWEST WILL DETACH
AND MOVE THROUGH THE NORTHERN STREAM...RACING THROUGH THE NORTHERN
PLAINS ON FRIDAY. WEAK SURFACE LOW/TROUGH WILL PUSH QUICKLY ACROSS
SOUTH DAKOTA AND LIKELY TO REACH NORTHWEST IOWA BY EVENING. WHILE
MOISTURE WILL BE LIMITED...AND SPEED OF SYSTEM REDUCING POTENTIAL
EFFICIENCY OF LIFT...TEMPERATURES ARE FAIRLY FAVORABLE FOR ICE
CRYSTAL GROWTH. USED LOWER TO MID LEVEL WARM AIR ADVECTION/QG
FORCING TO TIME OUT A SMALL THREAT FOR SNOWFALL FROM MIDDAY THROUGH
THE AFTERNOON GLANCING THE NORTHEASTERN 1/3 OF THE AREA. LITTLE
WINDOW FOR MIXING BEHIND THE WEAK SURFACE WAVE ACROSS THE SOUTHWEST
CWA BEFORE COLD AIR ADVECTION TAKES TOLL ON TEMPERATURES LATER IN
THE AFTERNOON. /CHAPMAN
FRIDAY NIGHT INTO SATURDAY WILL SEE A RIDGE OF HIGH PRESSURE PASS
THROUGH WITH RETURN FLOW ALOFT DEVELOPING...POSSIBLY SETTING UP A
BIT OF AN INVERSION. BUT...AS IS THE STORY EARLY THIS WINTER...NO
SNOW COVER SHOULD ALLOW A FAVORABLE WIND FOR MIXING TO DEVELOP AND
TEMPERATURES WILL LIKELY CLIMB AT LEAST INTO THE UPPER 30S TO LOWER
40S IN MOST SPOTS. EVEN PLANNING ON SOME MID TO UPPER 40S IN SOUTH
CENTRAL SOUTH DAKOTA. A FAIRLY WEAK PRESSURE GRADIENT ON SATURDAY
NIGHT WILL AID IN SOME DROP OFF IN TEMPERATURES...BUT STILL LOOKING
WELL ABOVE NORMAL.
IN THE LATTER PERIODS(SUN/WED)...A MARGINALLY AGREED UPON JET STREAK
WILL TRAVERSE THE NORTHERN PLAINS EARLY IN THE PERIOD...DROPPING A
COLD FRONT THROUGH ON MONDAY. A SOUTHERN STREAM CUT OFF LOW WILL
MOVE THROUGH KANSAS INTO MISSOURI AND SHOULD NOT REALLY AFFECT THE
AREA. SPLIT FLOW INTENSIFIES DURING THE SECOND HALF OF THE
PERIOD...ALTHOUGH THE MODELS DO INDICATE A DEEPER TROUGH TRYING TO
CARVE OUT OVER THE WESTERN UNITED STATES. HOWEVER...WITH A FAIRLY
STRONG NORTHERN STREAM IT APPEARS THAT IT WILL EJECT POSITIVELY
TILTED THUS NOT CREATING MUCH OF A PROBLEM FOR THE AREA. SO...WILL
GO ABOVE OR AT THE WARMEST GUIDANCE ON SUNDAY WITH A VERY FAVORABLE
FLOW AND ABSOLUTELY NO SNOW COVER ANYWHERE TO SPEAK OF. WILL
INCREASE LOWS A BIT ON SUNDAY NIGHT/MONDAY MORNING CLOSER TO THE RAW
OUTPUT WHICH GENERALLY HANDLES NIGHTS WITH WIND BETTER. COLDER AIR
IN ON MONDAY BUT WILL STILL LEAN TOWARDS MILDER GUIDANCE NUMBERS
WITH NO SNOW ON GROUND. MONDAY NIGHT A LITTLE TRICKY WITH A RIDGE OF
HIGH PRESSURE SLIPPING THROUGH...SO LOWERED LOWS JUST A BIT TO
COMPENSATE FOR THE POTENTIAL FOR A RADIATIONAL DROP OFF...ESPECIALLY
IN THE SOUTHERN CWA. NO BIG CHANGES FOR TUESDAY AND WEDNESDAY THIS
TIME AROUND...JUST A BIT WARMER ON TUESDAY WITH DECENT POTENTIAL LOW
LEVEL WIND FIELD. /08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1026 AM CST THU DEC 15 2011
.UPDATE...
SATELLITE STARTING TO SHOW SOME BREAKS IN THE STRATUS CLOUD DECK
ACROSS THE CWA THIS MORNING. THUS...ADJUSTED CLOUD COVER A LITTLE
THROUGH THE AFTERNOON. BREEZY/WINDY CONDITIONS WILL CONTINUE INTO
THE AFTERNOON ESPECIALLY EAST IN THE CWA. ADJUSTED TEMPERATURES
AND WINDS A LITTLE FOR THE REST OF THE DAY.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN ABUNDANCE OF STRATUS CLOUDS CONTINUE TO MOVE SOUTHEAST ACROSS
THE DAKOTAS...WITH THE EXTENT OF IT PUSHING WELL NORTH BACK INTO
SOUTHERN CANADA. WESTERN EDGE OF CLOUDS ACROSS SOUTH DAKOTA LIES
ALONG THE MISSOURI RIVER. ALTHOUGH...WITH A SOUTHEAST MOVEMENT TO
THE CLOUDS AND PLENTY LEFT UPSTREAM...EXPECTING THE EASTERN CWA TO
REMAIN IN CLOUDS MOST OF THE DAY. THE WESTERN CWA WILL LIKELY SEE
A BIT MORE SUNSHINE TODAY. MOST MODELS HAVING A HARD TIME PICKING
UP ON THE CLOUD COVER BUT THE RUC13 850 RH SEEMS TO HAVE A BETTER
HANDLE ON THINGS. IT WOULD SUGGEST CLOUD COVER THROUGH THE
AFTERNOON ACROSS THE EASTERN CWA...WITH THE WESTERN CWA IN MORE
SUNSHINE...AS PREVIOUSLY STATED. HAVE ALSO BEEN SEEING SCT
FLURRIES WITH THE STRATUS CLOUDS. PLENTY OF THAT UPSTREAM AS WELL
WITH KBIS AND KMBX RADARS SHOWING FLURRIES. EVEN OBS IN SOUTHERN
CANADA SHOWING -SN FROM TIME TO TIME. HAVE THEREFORE ADDED SCT
FLURRIES TO FORECAST THROUGH 18Z AND COULD BE A SITUATION WHERE IT
MAY NEED TO BE EXTENDED FURTHER INTO THE AFTERNOON ACROSS THE
EASTERN CWA WHEREVER STRATUS CLOUDS HANG ON THE LONGEST.
AGAIN...PLENTY OF ACTIVITY NOTED WELL UPSTREAM INTO SOUTHERN
CANADA. NORTHWEST WINDS WILL REMAIN BREEZY TODAY AS THE PRESSURE
GRADIENT REMAINS FAIRLY TIGHT WITH HIGH PRESSURE BUILDING IN.
HIGHEST SPEEDS WILL BE ACROSS THE EASTERN CWA WITH A DROP OFF IN
WINDS ACROSS THE WESTERN COUNTIES BY THIS AFTERNOON.
SFC HIGH WILL SETTLE IN OVER THE AREA TONIGHT BRINGING LIGHT
WINDS. NEXT ITEM TO WATCH WILL BE THE WEAK SHORTWAVE CROSSING THE
DAKOTAS LATE TONIGHT AND FRIDAY. MODELS STILL PEGGING MOST OF
THE LIGHT SNOWFALL ACROSS ND BUT THERE HAS BEEN A SLIGHT SHIFT
FURTHER SOUTH INTO NORTHERN SD. COUPLE MODELS BRINGING LIGHT QPF
INTO THE NORTHEASTERN COUNTIES AND SREF PROBS FOR .01 SHOWING
DECENT CHANCES ACROSS THE NORTHEASTERN CWA AS WELL. HAVE THEREFORE
INCREASED POPS SLIGHTLY FOR FRIDAY.
FOCUS WILL THEN SHIFT TO THE DEGREE OF WARMTH ON SATURDAY AS MILD
PACIFIC AIR BEGINS TO STREAM ACROSS THE NORTHERN PLAINS. WARM
FRONT CROSSES THE AREA DURING THE DAY SATURDAY WITH WINDS TURNING
WESTERLY. 850 MB TEMPS RISE TO JUST ABOVE ZERO C. WITH THE WIND
SHIFT AND A DECENT AMOUNT OF SUN...WILL SEE TEMPS RISE INTO THE
30S AND 40S.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
NOT MUCH TO TALK ABOUT IN THE EXTENDED FORECAST. CONSENSUS MODELS
ARE STILL GOING WITH CONTINUED DRY CONDITIONS. INTERESTINGLY THE
GFS IS STARTING TO HINT AT THE POSSIBILITY OF SOME PRECIP AT THE
END OF THE FORECAST PERIOD ASSOCIATED WITH THE NEXT UPPER TROF
THAT DIGS INTO THE PLAINS SO WILL NEED TO KEEP AN EYE ON HOW THAT
SYSTEM DEVELOPS. FOR NOW THOUGH LEFT THE FORECAST PRECIP FREE.
WITH THE LACK OF SNOW ON THE GROUND TEMPERATURES WILL ALSO
CONTINUE THE ABOVE NORMAL TREND WITH HIGHS STAYING NEAR 30 OR EVEN
CLIMBING INTO THE 40S THROUGH THE PERIOD.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
STRATUS REMAINS ACROSS THE REGION BUT HAS LIFTED TO AOA
2KFT. CIGS WILL BEGIN TO BREAK UP LATE THIS AFTERNOON...AND VISBY
IS EXPECTED TO REMAIN VFR. WINDS OUT OF THE NORTHWEST AT 20G30MPH
WILL CONTINUE THROUGH THIS MORNING BUT GRADUALLY DIMINISH FROM
WEST TO EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 AM CST THU DEC 15 2011
.SHORT TERM...TODAY THROUGH SATURDAY
343 AM CST THU DEC 15 2011
MAIN FORECAST CONCERNS ARE ON BLUSTERY NORTHWEST WINDS TODAY/CHANCES
FOR FREEZING DRIZZLE THIS MORNING...AND CLOUD COVER/FLURRIES
THROUGH THE DAY. FOCUS THEN TURNS TO SNOW CHANCES LATE FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A COLD FRONT EXTENDING FROM THE
NORTHERN LOWER MICHIGAN SOUTHWEST INTO NORTH CENTRAL MISSOURI.
SPRINKLES CONTINUE ACROSS THE FORECAST AREA THIS MORNING AS
STRATUS AND LOW LEVEL LIFT REMAIN IN PLACE. COLDER AIR WAS
FILTERING INTO THE REGION WITH TEMPERATURES FALLING INTO THE MID
30S. LOOK FOR TEMPERATURES TO CONTINUE FALLING THIS MORNING...WITH
THE POTENTIAL FOR FREEZING DRIZZLE THROUGH LATE MORNING.
LOW LEVEL SATURATION AND LIFT MAY PRODUCE SOME LIGHT FREEZING
DRIZZLE OR SNOW THIS MORNING...THEN SOME FLURRIES THIS AFTERNOON.
OTHERWISE PLAN ON CLOUDY SKIES TODAY WITH LOW LEVEL MOISTURE
REMAINING IN PLACE. MODELS ARE HAVING A DIFFICULT TIME HANDLING
THE LOW LEVEL MOISTURE TODAY...EXCEPT FOR THE RUC. HAVE TRENDED
CLOUDS AND TEMPERATURES TOWARDS THE RUC TODAY. ANY LINGERING
FREEZING DRIZZLE IS EXPECTED TO SWITCH OVER TO FLURRIES BY THIS
AFTERNOON AS COLDER AIR ALOFT MOVES IN. MESOSCALE MODELS INDICATE
PATCHY PRECIP ACROSS SOUTHEAST MINNESOTA AND MUCH OF WESTERN
WISCONSIN INTO THE AFTERNOON HOURS. THIS SIGNAL IS OFTEN
INDICATIVE OF FLURRIES OR DRIZZLE SO WILL HAVE TO KEEP A CLOSE EYE
ON THIS THROUGH THE MORNING HOURS. FORECAST SOUNDINGS SUGGEST MUCH
OF THE LOW LEVEL LIFT WILL BE LOST BY LATE AFTERNOON ALONG WITH
DRIER LOW LEVEL AIR PUSHING IN. THIS SHOULD END ANY LINGERING
PRECIPITATION. LOOK FOR BLUSTERY NORTHWEST WINDS TODAY...WITH
SPEEDS OF 15 TO 25 MPH AND GUSTS UP TO 40 MPH POSSIBLE. IT APPEARS
THAT WINDS WILL STAY BELOW ADVISORY CRITERIA SO WILL NOT BE
HOISTING A WIND ADVISORY TODAY. LOOK FOR HIGHS TO OCCUR EARLY THIS
MORNING...WITH TEMPERATURES FALLING THROUGH THE MORNING INTO THE
AFTERNOON. PLAN ON TEMPERATURES FALLING INTO THE UPPER 20S TO
LOWER 30S BY EARLY AFTERNOON. THE MAIN CONCERN TONIGHT WILL BE
CLOUD COVER AND LOW TEMPERATURES. LOOKING AT THE STRATUS
UPSTREAM...AND THE TRAJECTORIES...WOULD EXPECT THE CLOUDS TO
LINGER THROUGH TONIGHT. HAVE ADJUSTED LOWS UPWARD SLIGHTLY TO
ACCOUNT FOR THE EXPECTED CLOUD COVER. SHOULD SEE LOWS FALL INTO
THE UPPER TEENS TO LOWER 20S.
SURFACE HIGH PRESSURE IS EXPECTED TO MOVE OVER THE UPPER MISSISSIPPI
RIVER VALLEY ON FRIDAY WITH CLOUDS DECREASING ACROSS THE AREA EARLY
IN THE DAY...THEN GRADUALLY INCREASING FROM THE NORTHWEST LATE IN
THE AFTERNOON AS ANOTHER SYSTEM MOVES IN. 15.00 MODELS INDICATE A
SHORTWAVE TROUGH MOVING FROM NORTHEAST MONTANA THROUGH THE DAKOTAS
EARLY ON FRIDAY. THE SHORTWAVE WILL MOVE INTO THE FORECAST AREA LATE
FRIDAY AFTERNOON INTO FRIDAY EVENING...WITH POTENTIAL VORTICITY
ADVECTION OF 15 PVU/S IN THE 500-300 MB LAYER...MOVING INTO THE
FORECAST AREA EARLY. ISENTROPIC LIFT WILL INCREASE ACROSS THE AREA ON
THE 275-285 K SURFACES AS THE WAVE MOVES THROUGH. FORECAST SOUNDINGS
ARE SHOWING A 5000 FT DENDRITIC GROWTH ZONE FRIDAY EVENING. SHOULD
SEE A BRIEF SHOT OF SNOW FRIDAY EVENING. GIVEN THE SHORT DURATION OF
FORCING OVER THE AREA...SNOW ACCUMULATION SHOULD BE ON THE LIGHT
SIDE...RANGING FROM A HALF INCH TO PERHAPS A FEW LOCATIONS RECEIVING
AROUND 2 INCHES. HAVE INCREASED PRECIPITATION CHANCES ACROSS MUCH OF
THE FORECAST AREA FRIDAY EVENING INTO LATE FRIDAY NIGHT. CURRENT
THINKING IS THAT THE SNOW BAND WILL SET UP FROM SOUTHEAST MINNESOTA
THROUGH CENTRAL WISCONSIN...WITH THE GREATEST ACCUMULATIONS OCCURRING
ACROSS THESE AREAS. THE SNOW SHOULD TAPER OFF AFTER MIDNIGHT AS THE
SHORTWAVE MOVES INTO EASTERN WISCONSIN. LOOK FOR LOW TEMPERATURES TO
RANGE FROM THE MID TO UPPER TEENS ACROSS SOUTHEAST MINNESOTA THROUGH
NORTH CENTRAL WISCONSIN...TO THE LOWER 20S ACROSS FAR SOUTHWEST
WISCONSIN.
NORTHWEST FLOW ALOFT IS EXPECTED TO PERSIST ACROSS THE AREA ON
SATURDAY. A SHORTWAVE TROUGH WILL MOVE ACROSS LAKE SUPERIOR AND FAR
NORTHERN WISCONSIN DURING THE DAYTIME HOURS. MODELS ARE GENERATING
SOME LIGHT SNOW WITH THIS FEATURE AS IT MOVES THROUGH. THE SNOW
SHOULD STAY NORTH OF THE FORECAST AREA BUT WILL HAVE TO KEEP A CLOSE
WATCH ON THE NEXT SET OF MODEL RUNS. A FEW FLURRIES COULD FALL
ACROSS NORTH CENTRAL WISCONSIN AS THIS WAVE MOVES THROUGH. THE MAIN
IMPACT THE WAVE WILL HAVE ON THE FORECAST AREA...IS INCREASING CLOUD
COVER. LOOK FOR HIGH TEMPERATURES ON SATURDAY TO RANGE FROM THE
UPPER 20S ACROSS NORTH CENTRAL WISCONSIN TO THE MID 30S ACROSS
NORTHEAST IOWA THROUGH FAR SOUTHWEST WISCONSIN. 250 MB JET STREAK
WILL MOVE ACROSS THE REGION SATURDAY NIGHT. A SURFACE RIDGE IS
EXPECTED TO MOVE DURING THE OVERNIGHT HOURS PROVIDING MOSTLY CLEAR
SKIES. 850 MB TEMPERATURES WILL WARM THROUGH THE NIGHT...STARTING
OUT AROUND -2C AT 00Z AND WARMING TO PLUS 2 C BY 12 SUNDAY. FORECAST
SOUNDINGS ARE SHOWING THE COLD AIR HOLDING STRONG NEAR THE SURFACE
AS WARM AIR MOVES IN ALOFT. THE SOUNDINGS ALSO SATURATE NEAR THE
SURFACE SUGGESTING SOME LOW CLOUD/FOG DEVELOPMENT. LOOK FOR LOWS TO
FALL INTO THE 20S SATURDAY NIGHT.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
343 AM CST THU DEC 15 2011
15.00 MEDIUM RANGE MODELS CONTINUE TO SHOW A SPLIT FLOW PATTERN
PERSISTING ACROSS THE CONUS INTO THE MIDDLE OF NEXT WEEK. A COLD
FRONT IS EXPECTED TO SAG SOUTH ACROSS THE FORECAST AREA ON LATE
SUNDAY INTO MONDAY. THIS SYSTEM MAY BRING SOME LIGHT SNOW TO THE
AREA BUT MOISTURE WILL BE LACKING...SO ANY SNOWFALL AMOUNTS WOULD
LIKELY BE MINIMAL. THE GFS AND NAM TAKE AN UPPER LOW OVER THE
SOUTHWEST CONUS...EAST INTO THE SOUTHERN PLAINS LATE MONDAY INTO
TUESDAY. THE MODELS THEN TAKE THE LOW ACROSS THE MID MISSISSIPPI
RIVER VALLEY LATE TUESDAY INTO WEDNESDAY. MUCH OF THE PRECIPITATION
LOOKS TO STAY WELL SOUTH OF THE AREA. A MAJORITY OF THE GFS ENSEMBLE
MEMBERS ARE ALSO IN FAVOR OF THE SOUTHERN TRACK. THE GEM OFFERS A
DIFFERENT SOLUTION...TAKING THE LOW INTO THE CENTRAL PLAINS LATE
MONDAY AND LIFTING IT ACROSS SOUTHERN IOWA INTO SOUTHEAST WISCONSIN ON
TUESDAY. WILL CONTINUE A MODEL CONSENSUS BLEND DURING THIS
TIMEFRAME...KEEPING PRECIPITATION CHANCES MAINLY ALONG AND SOUTH OF
THE I-90 CORRIDOR LATE MONDAY NIGHT INTO TUESDAY. PLAN ON HIGHS
GENERALLY IN THE 30S MONDAY THROUGH WEDNESDAY...WITH LOWS IN THE 20S.
&&
.AVIATION...THROUGH 18Z FRIDAY
1135 AM CST THU DEC 15 2011
MAIN CONCERN WILL BE GUSTY NORTHWEST SURFACE WINDS THIS AFTERNOON
IN TIGHT PRESSURE BETWEEN LOW PRESSURE OVER SOUTHERN ONTARIO AND
HIGH PRESSURE ACROSS THE PLAINS. LOOK FOR SUSTAINED NORTHWEST
WINDS IN THE 15-25KT RANGE WITH GUSTS IN THE 30-40KT RANGE. EXPECT
THESE WINDS TO SUBSIDE FAIRLY RAPIDLY THIS EVENING. OTHERWISE...
STRATOCUMULUS CEILINGS HAVE BEEN RISING THROUGH THIS MORNING AND
ARE NOW IN VFR CATEGORY AT BOTH KRST/KLSE AS OF 17Z. THERE WERE
ALSO A FEW SNOW SHOWERS MAINLY NORTH OF THE I-90 CORRIDOR IN
WISCONSIN. HAVE THEREFORE OPTED TO CARRY A P6SM -SHSN IN THE KLSE
TAF THROUGH THE AFTERNOON. ALONG WITH DIMINISHING WINDS...LOOK FOR
A GRADUAL DECREASE IN CLOUDS THROUGH THIS EVENING AS WELL. VFR
CONDITIONS EXPECTED TO CONTINUE THROUGH FRIDAY MORNING AS THE RIDGE
OF HIGH PRESSURE DRIFTS ACROSS THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
343 AM CST THU DEC 15 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...DAS