Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 11/21/11
AREA FORECAST DISCUSSION
NWS TOPEKA KS
542 PM CST SUN NOV 20 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SURFACE RIDGING AND CLOUD COVER HAVE PREVENT TEMPS FROM WARMING UP
MUCH THIS AFTERNOON. 20Z SURFACE OBS CONTINUE TO SHOW COLD AIR
ADVECTING FROM THE NORTH WITH THE CENTER OF THE RIDGE OVER SOUTHERN
MN. ALOFT...WATER VAPOR SHOWS A CLOSED LOW OVER THE CA COAST AND
PROFILER DATA INDICATES A FAST SOUTHWEST FLOW OVER THE FORECAST AREA
WITH NO OBVIOUS WAVE WITHIN THE FLOW. HOWEVER THE RUC AND NAM
INDICATE A WEAK WAVE AT 700 MB MOVING ACROSS NORTHEAST KANSAS LATE
THIS AFTERNOON AND THIS EVENING. THIS MAY BE THE CAUSE OF THE
ENHANCED CLOUD COVER AND WEAK ECHOS ON RADAR ACROSS WESTERN KS.
THINK THAT THIS WILL NOT AMOUNT TO MUCH FOR TONIGHT DUE TO MID LEVEL
DRY AIR. MODELS SHOW THIS PASSING EAST WITH GENERAL SUBSIDENCE
TAKING OVER FOR MUCH OF THE NIGHT. ADDITIONALLY ISENTROPIC SURFACES
ARE NOT SHOWING MUCH LIFT EITHER. THEREFORE WILL CONTINUE WITH A DRY
FORECAST. CLOUD COVER COULD BE A LITTLE TRICKY TONIGHT AND HAVE A
LARGE EFFECT ON MIN TEMPS. THERE IS A GENERAL CONSENSUS THAT THE LOW
LEVEL RH OVER SOUTHERN MO AND SOUTHEAST KS WILL LIFT NORTH THROUGH
NORTHEAST KS OVERNIGHT. MEANWHILE SKIES COULD BECOME MOSTLY CLEAR
OVER CENTRAL KS. WITH THIS IN MIND HAVE DROPPED LOWS INTO THE LOWER
20S FROM MHK WEST AND LEFT LOWS IN THE LOWER 30S OVER FAR EASTERN KS
WHERE LOW CLOUDS ARE LIKELY TO HANG IN A LITTLE LONGER. FOR MONDAY
THINK TEMPS WILL WARM INTO THE MID 40S DUE TO NEUTRAL TEMP ADVECTION
AND SOME INSOLATION DURING THE DAY. MID LEVEL MOISTURE IS EXPECTED
TO BEGIN ADVECTING NORTH BY MONDAY AFTERNOON AS THE CLOSED LOW ON
THE WEST COAST MAKES ITS WAY OVER THE SOUTHERN ROCKIES. HAVE
INCLUDED SOME SLIGHT CHANCE POPS SOUTH OF I-70 DURING THE AFTERNOON
BECAUSE OF THIS.
WOLTERS
UPPER WAVE CONTINUES EAST AND NORTHEAST WHILE DEEPENING MONDAY
NIGHT. UPPER JET STREAKS FLANKING THE AREA TO THE NORTHEAST AND
SOUTHWEST INTO THE EVENING WITH DRY SLOT WORKING THROUGH SOUTHERN
KANSAS AND SOMEWHAT OF A WEAK TROWAL POKING INTO NORTHEAST KANSAS.
THERE REMAINS SOME DIFFERENCES ON THE TIMING OF THE SYSTEM WITH THE
12Z NAM ON THE FASTER END...BUT STILL APPEARS LATE EVENING THROUGH
EARLY MORNING TUESDAY WILL BE ON THE WET SIDE. DRY SLOT WILL HELP
AID CONVECTIVE CHANCES AND INSTABILITY STILL ENOUGH FOR THUNDER
INCLUSION FOR MUCH OF THE AREA. ALSO SOME CONCERN FOR FREEZING
PRECIP LATE IN THE EVENT AS SURFACE LOW PRESSURE MOVES THROUGH
SOUTHERN MISSOURI AND NORTH WINDS TAKE HOLD. WILL INTRODUCE A
FREEZING RAIN MENTION IN THE NORTHWEST. TUESDAY AFTERNOON AND NIGHT
BRING RAPIDLY IMPROVING CONDITIONS AS UPPER RIDGING BUILDS IN.
AIRMASS BEHIND THE SYSTEM NOT TERRIBLY COLD WITH DOWNSLOPE WINDS TO
THE NORTHWEST SO HIGHS SHOULD STILL REACH THE LOWER 50S TUESDAY AND
ON INTO THE UPPER 50S WEDNESDAY UNDER CLEAR SKIES AND INCREASING
SOUTH WINDS.
65
EXTENDED FORECAST (WEDNESDAY NIGHT THROUGH SUNDAY)
SOUTHERLY FLOW...WARM AIR ADVECTION AND UPPER LEVEL RIDGING WILL
RETURN TO THE CENTRAL U.S. ON THANKSGIVING DAY. HIGH TEMPERATURES
ARE EXPECTED TO QUICKLY REBOUND INTO THE LOW 60S. SOUTH WINDS WILL
BE STRONG AND GUSTY ON THANKSGIVING DAY WITH A STRONG PRESSURE
GRADIENT BETWEEN A SURFACE HIGH OVER THE SOUTHEASTERN U.S. AND
SURFACE LOW FORMING ALONG THE ROCKY MOUNTAINS. MODELS ARE INDICATING
A LONGWAVE TROUGH WILL MOVE OUT OF THE ROCKY MOUNTAINS ON FRIDAY
ALONG WITH THE SURFACE LOW AND COLD FRONT. ENOUGH ELEVATED
INSTABILITY WILL EXIST AHEAD OF THE APPROACHING FRONT FOR A FEW
THUNDERSTORMS DURING THE DAY ON FRIDAY.
MODELS QUICKLY DIVERGE INTO NEXT WEEKEND. THE OPERATIONAL GFS AND
DGEX BRING THE COLD FRONT THROUGH THE CWA FRIDAY NIGHT AND THEN
CLOSE OFF AN UPPER LEVEL LOW OVER THE MID-MISSISSIPPI RIVER VALLEY.
THE 12Z ECMWF BRINGS THE FRONT THROUGH THE CWA SATURDAY MORNING BUT
THEN CLOSES THE UPPER LEVEL LOW OFF IN NORTHEASTERN OKLAHOMA. THE
ECMWF SOLUTION WOULD KEEP PRECIPITATION CHANCES IN THE FORECAST FOR
THE MAJORITY OF HOLIDAY WEEKEND. FOR THE FORECAST HAVE FAVORED THE
MORE PROGRESSIVE SOLUTIONS OF THE GFS AND DGEX WITH MANY OF THE GFS
ENSEMBLES INDICATING A MORE PROGRESSIVE UPPER LEVEL WAVE.
ANDERSON
&&
.AVIATION...
MVFR CONDITIONS CURRENTLY AT KFOE AND SHOULD SHORTLY ARRIVE AT
KTOP. MVFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE
OVERNIGHT WITH MOISTURE BEING LIFTED ISENTROPICALLY IN THE LOWER
LEVELS. BEST LIFT APPEARS TO REMAIN EAST OF KMHK. THEREFORE...LEFT
KMHK VFR. CEILINGS AT KTOP AND KFOE SHOULD IMPROVE TO VFR AROUND
15Z TOMORROW.
ANDERSON
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
405 PM EST SAT NOV 19 2011
.SYNOPSIS...
HIGH PRESSURE PUSHES FARTHER OUT TO SEA TONIGHT AND SUNDAY. A
FRONT WILL APPROACH FROM THE NORTHWEST LATE SUNDAY...AND BECOME
NEARLY STATIONARY OVER THE REGION MONDAY AND MONDAY NIGHT. THE
FRONT WILL LIFT NORTH OF THE AREA AS A WARM FRONT ON TUESDAY. A
COLD FRONT WILL THEN PUSH THROUGH THE MID ATLANTIC STATES ON
WEDNESDAY...WITH HIGH PRESSURE BUILDING IN FROM THE WEST
THANKSGIVING DAY INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
CURRENT SFC ANALYSIS SHOWS HIGH PRESSURE CENTERED WELL OFF THE
DELMARVA COAST. RETURN SW FLOW AROUND THE BACKSIDE OF THE HIGH HAS
PROVIDED A MILDER DAY ACROSS THE FCST REGION...WHILE ALSO BRINGING
PERIODIC WAA CLOUDINESS (MAINLY UPPER LEVEL). LLVL TRAJECTORIES
OUT OF THE GULF STREAM (BTWN ILM-MHX) DID PROVIDE A PERIOD OF
ENHANCED LLVL THETA-E WITH THE HIGHER DWPTS...WHICH IN TURN LED TO
THE DEVELOPMENT OF A SHALLOW STRATO-CU DECK THAT PERSISTED FOR A
WHILE FROM THE LATE AM INTO EARLY AFTN HRS BEFORE MIXING OUT.
FOR THE OVERNIGHT HOURS...THE MAIN FCST CHALLENGE WILL BE WITH
CLOUD COVER...ESPECIALLY REGARDING THE DEVELOPMENT OF ANY LOWER
CLOUD DECKS (STRATUS LAYERS) WITH THE LIGHT S/SW FLOW. BOTH THE
GFS/NAM AS WELL AS THE RUC FCST SOUNDINGS ALL SHOW A HIGH
POTENTIAL FOR THE DEVELOPMENT OF A LOWER CLOUD DECK...WITH A
STRONG SFC-BASED INVERSION WITH TEMPS AS WELL AS MIXING RATIO
(MSTR) THROUGH 1000-975 MB. HOWEVER...MOST OF THE NUMERICAL
GUIDANCE IS NOT PICKING UP ON THESE CLOUDS...THOUGH PER THE FCST
SOUNDINGS...OTHER LOWER LAYER MSTR (BTWN 900-800 MB) IS NOTED...
PARTICULARLY E OF I-95. THE UPSHOT IS LOWER THAN AVERAGE
CONFIDENCE IN TERMS OF THE SKY FCST OVERNIGHT...THOUGH BELIEVE
THERE IS ENOUGH EVIDENCE TO GO WITH A TREND TOWARD MOSTLY CLOUDY
LATE TONIGHT/EARLY SUN. LOWS NOT AS COLD COMPARED TO THE LAST
COUPLE NIGHTS...GIVEN THE CLOUD COVER AND S/SW FLOW UNDER 10 KTS.
MIN TEMPS GENERALLY THROUGH THE 40S.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
MID/UPR LVL FLO WILL BECOME MORE ZNL ACRS THE FA LATER SUN THRU
MON. THE RESULT WILL BE A FRNTL BNDRY THAT WILL DROP INTO THE AREA
TO NEAR THE VA/NC BORDER. THERE WILL BE MORE CLDS ACRS THE NRN/NW
CNTIES BY LATE IN THE DAY...AS THE FRNT APPROACHES FM THE NW.
OTHRWISE...DRY AND MILD CONDITIONS WILL PREVAIL ON SUN WITH MUCH
OF THE REGION GENERALLY PRTLY SNY. MAX TEMPS WILL BE IN THE MID TO
UPR 60S MOST LOCATIONS...THOUGH CANNOT RULE OUT 70+ READINGS OVER
THE FAR SRN PTNS (ALONG/S OF THE VA/NC BORDER) WITH THE GREATER
AMOUNT OF SUNSHINE.
SFC FRNTL BNDRY THEN DROPS INTO THE AREA SUN NGT THRU MON...
STALLING NEAR THE VA/NC BORDER BY LATE MON. GOING WITH HIEST POPS
NEAR 50 PERCENT ACRS THE N-NW 1/3 OF THE AREA LATE SUN NGT AND
MON...DECREASING TO SLGT CHC POPS OVR SRN 1/3 OF THE REGION. LOWS
SUN NGT IN THE UPR 40S TO MID 50S. HIGHS ON MON QUITE VARIABLE
ONCE AGAIN...FROM THE UPPER 50S/NEAR 60 TO LOWER 70S OVER SRN
VA/NERN NC. BECMG MSTLY CLDY OR CLDY SUN NGT...AND MSTLY CLDY OR
CLDY ON MON.
STALLED FRONTAL BOUNDARY ACROSS RGN MONDAY NIGHT SLOWLY LIFTS N
AS A WARM FRONT TUESDAY IN RESPONSE TO LOW PRESSURE APPROACHING
FROM THE W. WILL KEEP CHC POPS IN FCST ON TUE...AGAIN WITH THE
HIGHEST CHANCES OVER THE NRN TIER. LOWS TUE AM IN U40S-M50S...
HIGHS FROM THE M60S FAR N TO THE L70S S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOLLOWING THE SLOWER ECMWF SOLN WRT THE COLD FRNTL PASSAGE WED.
LOW PRS MOVES NE THRU OHIO VLLY TUE NITE WITH ASSCTD WRM FRONT
LIFTG N ACROSS THE AREA. MILD WITH CHC SHWRS. LOWS IN THE 50S
AS FA BECOMES WRM SCTRD. TRAILING COLD FRONT CROSSES FA WED AFTRN
THEN EXITS OFFSHORE WED EVE. AGAIN THIS THE SLOWER SOLN THAN GFS
WHICH HAS A FROPA WED MORN. KEPT CHC POPS ATTM BUT ADDED THUNDER
AS DATA SUGGESTS MRGINAL INSTAB AHEAD OF BNDRY. HIGHS IN THE 60S
TO NR 70.
LINGERING SHWRS ALONG THE COAST WED EVE...FOLLOWED BY STRNG CAA
WED NITE INTO THURSDAY AS LOW PRS DEEPENS TO THE NE AND 1030MB
HIGH PRS BLDG INTO RGN FROM W. DRY BUT COOL THUR AND FRI. HIGHS
THU 50-55...M-U50S FRI. LOWS IN THE 30S. DRY AND MILDER SAT WITH
MORE CLOUD COVER. HIGHS U50S-L60S.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE SHIFTS OFF THE COAST ALLOWING FOR A SW WIND ACROSS
THE REGION. THIS SOUTHERLY FLOW A WILL ALLOW FOR MOISTURE OVER
THE SOUTHEAST TO SPREAD N. SATELLITE SHOWING STRATOCU OVER HAMPTON
ROADS AND CENTRAL NC MOVG N/NE WITH FLOW. BELIEVE THIS MOISTURE
WILL AFFECT THE REGION OVERNIGHT AND WITH SOUNDING INDICATING
INVERSION SETTING UP...MAY SEE SOME STRATUS AROUND 1000-2000 FT
DEVELOP IN THE EARLY MORNING HOURS. THIS SHOULD IMPROVE TO VFR BY
LATE MORNING TO AFTERNOON.
DRY AND VFR CONDITIONS SHOULD CONTINUE INTO MONDAY BEFORE BEFORE
THE NEXT FRONT APPROACHES LATE MONDAY.
&&
.MARINE...
NO FLAGS THRU THE WEEKEND AS HIGH PRS PARKS ITSELF OFF THE SERN
COAST. RETURN S-SW FLOW AOB 15 KTS THRU SUN NIGHT. SEAS 2-3 FT.
BACKDOOR TYPE COLD FRONT SAGS S ACROSS MID ATLNTC COAST MON BUT
A QSTN IS TO HOW FAR S THE BNDRY ACTUALLY GETS. WINDS SHFT INTO
N-NE BY MON AFTRN BUT LTST DATA KEEPS CONDITIONS BLO SCA LVLS.
THIS BNDRY PROGGED TO LIFT BACK N AS A WARM FRONT TUE NITE IN
RESPONSE TO LOW PRS APPRCHG FROM THE S. NXT CHC FOR FLAGS COMES
WED INTO THU AS S WNDS INCRS AHEAD AHEAD OF CDFRNT. STRNG CAA
PROGGED BEHIND BNDRY WED NITE INTO THU. MAY EVEN SEE NW GALES
WITH THIS EVENT BUT CAPPED GUSTS AT 30 KTS FOR NOW.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...MPR
AVIATION...JEF
MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 PM EST SAT NOV 19 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS AND A FLAT RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE CNTRL ROCKIES TO THE UPPER GREAT LAKES. A GROWING
AREA OF COLDER CLOUD TOPS WAS DEVELOPING OVER THE NRN PLAINS IN
ADVANCE OF A STRONG SHORTWAVE TROUGH OVER SRN WY INTO NRN CO. AT THE
SFC...A TROUGH/FRONT EXTENDED FROM CNTRL UPPER MI THROUGH CNTRL WI
AND NE IA TO LOW PRES OVER WRN KS. RADARS INDICATED SNOW DEVELOPING
OVER SD ALIGNED WITH STRONG 700-600 MB FGEN.
&&
.DISCUSSION...
TODAY AND TONIGHT...MODELS WERE IN REASONABLY GOOD AGREEMENT WITH
THE TRACK OF THE LOW AND MAIN MID/UPPER LEVEL FEATURES. THE CNTRL
PLAINS LOW IS EXPECTED TO MOVE QUICKLY TO SW WI BY 00Z/SUN AND INTO
NRN LAKE HURON BY 06Z. A PERIOD OF STRONG MID/UPPER LEVEL FORCING IS
EXPECTED WITH THIS SYSTEM AS A COUPLED UPPER LEVEL JET STRUCTURE
PROVIDES STRONG UPPER LEVEL DIV AND INDUCES STRONG MID LEVEL FGEN.
THE NAM AND GFS HAVE BEEN CONSISTENT WITH THE POSITION OF THE
700-600 MB FGEN AND THE ASSOCIATED BAND OF STRONG ASCENT. THIS SHOULD
PLACE THE HEAVIER BAND OF PCPN FROM NEAR IWD TO MQT. MDL QPF AMOUNTS
OF 0.30 TO 0.50 INCHES SEEMS ON TRACK GIVEN THE AVAILABILITY OF 4
G/KG IN THE 290K-295 LAYER ( NEAR 700 MB). ALTHOUGH THE DGZ IS
EXPECTED TO BE RELATIVELY HIGH FROM ABOUT 10K TO 15K FT...IT
COINCIDES WITH THE STRONGER UPWARD MOTION SO THAT AVERAGE SNOW/WATER
RATIO VALUES TO AT LEAST 14/1 ARE EXPECTED DURING THE PERIOD OF
HEAVIER SNOW. THIS WOULD RESULT IN SNOWFALL AMOUNTS GENERALLY IN THE
4 TO 6 INCH RANGE. LAKE AND UPSLOPE TERRAIN ENHANCEMENT WITH BACKING
WINDS FROM NE TO N NEAR IWD AND MQT SHOULD BOOST SNOWFALL AMOUNTS BY
SEVERAL INCHES EVEN THOUGH THE STRONGER SYNOPTIC LIFT MOVES OFF TO
THE ENE QUICKLY BTWN 00Z-06Z. SO...UPGRADED WINTER WX ADVISORIES IN
THOSE LOCATIONS TO WARNINGS WHERE LCL AMOUNTS IN THE 6 TO 8 INCH
RANGE ARE EXPECTED. WITH A LATER CHANGEOVER TO SNOW IN ALGER COUNTY
WITH FCST SNOWFALL IN THE 2 TO 4 INCH RANGE...A WINTER WX ADVY WAS
ALSO POSTED.
THE RAIN SNOW LINE FROM ABOUT P53 TO JUST SE OF IMT THIS AFTERNOON
AND EARLY EVENING...BASED ON 00Z NAM CRITICAL THICKNESS AND WET-BULB
ZERO HEIGHTS...WILL SHIFT QUICKLY TO THE SE THIS EVENING AS THE LOW
MOVES EAST OF THE REGION. SO...SNOWFALL AMOUNTS OF AN INCH OR TWO
ARE ALSO POSSIBLE OVER THE SOUTH AND EAST.
SUNDAY....N TO NW WINDS AND 850 MB TEMPS AROUND -10C/-11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES SHOULD END.
MONDAY...THE COMBINATION OF WAA AND A WEAK SHORTWAVE TROUGH MOVING
NEAR THE CANADA BORDER COULD BRING SOME LIGHT SNOW TO THE NRN GREAT
LAKES. HOWEVER...MOST OF THE PCPN WITH THIS SYSTEM SHOULD REMAIN
NORTH OF THE CWA...PER ECMWF/NAM.
FOR THE EXTENDED...
OVERALL...FAIRLY QUIET EXTENDED PERIOD PCPN WISE WITH WARM TEMPS THE
MAIN STORY LATE IN THE PERIOD. WEAK SHORTWAVE SLIDES ACROSS THE AREA
ON TUES INTO TUES NIGHT. UNCERTAINTY IN AMNT OF H850-700
MOISTURE...WITH MOST OF IT LOCATED IN SRN ONTARIO...SO WILL GO WITH
A DRY FORECAST FOR NOW. THEN STRONG RIDGE DEVELOPING OVER THE NRN
ROCKIES AT THE BEGINNING OF THE WEEK IS EXPECTED TO SHIFT EAST AND
OVER THE GREAT LAKES AREA ON WEDNESDAY AND REMAIN THROUGH FRI. THIS
WILL LEAD TO A WARM UP FOR THANKSGIVING DAY AND BLACK FRIDAY...WITH
HIGHS APPROACHING RECORD VALUES. SEVERAL FACTORS THAT COULD DISRUPT
THE WARM TEMPS...STRENGTH OF THE INVERSION...IF STRATUS DECK
DEVELOPS AND LINGERING SNOW COVER. H850 TEMPS RISE TOWARDS 8-10C ON
THURS AND REMAIN AROUND 7-8C ON FRI. THIS CREATES H850 TEMP
STANDARDIZED ANOMALIES THAT WILL APPROACH 2.5 FOR THURS AND 2.0 ON
FRI. CONCERN WOULD BE HOW DEEP MIXING WOULD OCCUR INTO THE SHARP
INVERSION SEEN ON ECMWF/GFS. GFS DOES HINT AT THE POTENTIAL FOR A
STRATUS DECK WILL MOISTURE TRAPPED BELOW THE INVERSION...WHICH COULD
KEEP TEMPS COOLER. BUT IF THAT DOESN/T OCCUR...ABUNDANT DRY AIR
ALOFT WOULD LEAD TO A DECENT WARM-UP AND CURRENTLY HAVE VALUES IN
THE UPPER 40S. WITH THE SOUTHWEST WINDS...EXPECT THE HIGHEST TEMPS
/AT LEAST LOWER 50S/ OVER THE DOWNSLOPE AREAS NEAR LK
SUPERIOR...ESPECIALLY IN LOCATIONS LACKING SNOW COVER.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
THE SW TO NE ORIENTED STATIONARY FRONT ACROSS THE EASTERN HALF OF
UPPER MI WILL SLIDE EASTWARD OVERNIGHT IN RESPONSE TO THE LOW
NEARING FROM THE SW...WHICH SHOULD BE ACROSS NORTHERN LOWER MI BY
06Z. THE RESULT WILL CONTINUE TO BE AN INFLUX OF COOLER AIR...AND
STRONG NORTHERLY WINDS. MOISTURE STREAMING NORTHWARD AHEAD OF THE
LOW WILL CONTINUE MODERAT TO HEAVY SNOW AT TIMES...ESPECIALLY AT
KIWD/KSAW...WHICH COULD PRODUCE LIFR CIGS/VSBYS...THIS AFTERNOON AND
EVENING. EXPECT THE N WINDS TO DIMINISH TOWARDS DAYBREAK AS HIGH
PRESSURE NEARS FROM THE WEST...WITH WINDS BECOMING NW WEST TO EAST
OVER THE MORNING HOURS SUNDAY. THIS WILL MEAN SIGNIFICANT DRYING IN
THE MID LEVELS...WITH A QUICK END TO LAKE EFFECT/ENHANCED SNOW
SHOWERS AT ALL 3 TAF SITES.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A LOW PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS THIS MORNING TO
NORTHERN LOWER MICHIGAN TONIGHT WILL BRING INCREASING NORTH TO
NORTHEAST WINDS TODAY INTO TONIGHT. THERE COULD BE A FEW NORTHERLY
GALE FORCE GUSTS TO 35KTS WITH THE PASSAGE OF THE LOW
TONIGHT...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WITH THE
FAST EXIT OF THE LOW ON SUNDAY...EXPECT WINDS TO QUICKLY DIMINISH AS
HIGH PRESSURE SETTLES OVER LK SUPERIOR. THIS HIGH WILL REMAIN OVER
THE GREAT LAKES THROUGH THE FIRST HALF OF THE WORK WEEK...AS ANOTHER
LOW MOVES THROUGH THE OHIO RIVER VALLEY TUESDAY INTO WEDNESDAY. WEAK
SFC TROUGH MOVING THROUGH ONTARIO ON MON COULD PRODUCE A FEW
SOUTHWEST GUSTS OF 25-30KTS OVER NRN LK SUPERIOR...OTHERWISE EXPECT
WINDS TO STAY BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ006.
WINTER STORM WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-
004-005-009.
WINTER WEATHER ADVISORY UNTIL 3 AM EST /2 AM CST/ SUNDAY FOR
MIZ001-003-010-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...KF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
639 AM EST SAT NOV 19 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS AND A FLAT RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE CNTRL ROCKIES TO THE UPPER GREAT LAKES. A GROWING
AREA OF COLDER CLOUD TOPS WAS DEVELOPING OVER THE NRN PLAINS IN
ADVANCE OF A STRONG SHORTWAVE TROUGH OVER SRN WY INTO NRN CO. AT THE
SFC...A TROUGH/FRONT EXTENDED FROM CNTRL UPPER MI THROUGH CNTRL WI
AND NE IA TO LOW PRES OVER WRN KS. RADARS INDICATED SNOW DEVELOPING
OVER SD ALIGNED WITH STRONG 700-600 MB FGEN.
&&
.DISCUSSION...
TODAY AND TONIGHT...MODELS WERE IN REASONABLY GOOD AGREEMENT WITH
THE TRACK OF THE LOW AND MAIN MID/UPPER LEVEL FEATURES. THE CNTRL
PLAINS LOW IS EXPECTED TO MOVE QUICKLY TO SW WI BY 00Z/SUN AND INTO
NRN LAKE HURON BY 06Z. A PERIOD OF STRONG MID/UPPER LEVEL FORCING IS
EXPECTED WITH THIS SYSTEM AS A COUPLED UPPER LEVEL JET STRUCTURE
PROVIDES STRONG UPPER LEVEL DIV AND INDUCES STRONG MID LEVEL FGEN.
THE NAM AND GFS HAVE BEEN CONSISTENT WITH THE POSITION OF THE
700-600 MB FGEN AND THE ASSOCIATED BAND OF STRONG ASCENT. THIS SHOULD
PLACE THE HEAVIER BAND OF PCPN FROM NEAR IWD TO MQT. MDL QPF AMOUNTS
OF 0.30 TO 0.50 INCHES SEEMS ON TRACK GIVEN THE AVAILABILITY OF 4
G/KG IN THE 290K-295 LAYER ( NEAR 700 MB). ALTHOUGH THE DGZ IS
EXPECTED TO BE RELATIVELY HIGH FROM ABOUT 10K TO 15K FT...IT
COINCIDES WITH THE STRONGER UPWARD MOTION SO THAT AVERAGE SNOW/WATER
RATIO VALUES TO AT LEAST 14/1 ARE EXPECTED DURING THE PERIOD OF
HEAVIER SNOW. THIS WOULD RESULT IN SNOWFALL AMOUNTS GENERALLY IN THE
4 TO 6 INCH RANGE. LAKE AND UPSLOPE TERRAIN ENHANCEMENT WITH BACKING
WINDS FROM NE TO N NEAR IWD AND MQT SHOULD BOOST SNOWFALL AMOUNTS BY
SEVERAL INCHES EVEN THOUGH THE STRONGER SYNOPTIC LIFT MOVES OFF TO
THE ENE QUICKLY BTWN 00Z-06Z. SO...UPGRADED WINTER WX ADVISORIES IN
THOSE LOCATIONS TO WARNINGS WHERE LCL AMOUNTS IN THE 6 TO 8 INCH
RANGE ARE EXPECTED. WITH A LATER CHANGEOVER TO SNOW IN ALGER COUNTY
WITH FCST SNOWFALL IN THE 2 TO 4 INCH RANGE...A WINTER WX ADVY WAS
ALSO POSTED.
THE RAIN SNOW LINE FROM ABOUT P53 TO JUST SE OF IMT THIS AFTERNOON
AND EARLY EVENING...BASED ON 00Z NAM CRITICAL THICKNESS AND WET-BULB
ZERO HEIGHTS...WILL SHIFT QUICKLY TO THE SE THIS EVENING AS THE LOW
MOVES EAST OF THE REGION. SO...SNOWFALL AMOUNTS OF AN INCH OR TWO
ARE ALSO POSSIBLE OVER THE SOUTH AND EAST.
SUNDAY....N TO NW WINDS AND 850 MB TEMPS AROUND -10C/-11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES SHOULD END.
MONDAY...THE COMBINATION OF WAA AND A WEAK SHORTWAVE TROUGH MOVING
NEAR THE CANADA BORDER COULD BRING SOME LIGHT SNOW TO THE NRN GREAT
LAKES. HOWEVER...MOST OF THE PCPN WITH THIS SYSTEM SHOULD REMAIN
NORTH OF THE CWA...PER ECMWF/NAM.
FOR THE EXTENDED...
OVERALL...FAIRLY QUIET EXTENDED PERIOD PCPN WISE WITH WARM TEMPS THE
MAIN STORY LATE IN THE PERIOD. WEAK SHORTWAVE SLIDES ACROSS THE AREA
ON TUES INTO TUES NIGHT. UNCERTAINTY IN AMNT OF H850-700
MOISTURE...WITH MOST OF IT LOCATED IN SRN ONTARIO...SO WILL GO WITH
A DRY FORECAST FOR NOW. THEN STRONG RIDGE DEVELOPING OVER THE NRN
ROCKIES AT THE BEGINNING OF THE WEEK IS EXPECTED TO SHIFT EAST AND
OVER THE GREAT LAKES AREA ON WEDNESDAY AND REMAIN THROUGH FRI. THIS
WILL LEAD TO A WARM UP FOR THANKSGIVING DAY AND BLACK FRIDAY...WITH
HIGHS APPROACHING RECORD VALUES. SEVERAL FACTORS THAT COULD DISRUPT
THE WARM TEMPS...STRENGTH OF THE INVERSION...IF STRATUS DECK
DEVELOPS AND LINGERING SNOW COVER. H850 TEMPS RISE TOWARDS 8-10C ON
THURS AND REMAIN AROUND 7-8C ON FRI. THIS CREATES H850 TEMP
STANDARDIZED ANOMALIES THAT WILL APPROACH 2.5 FOR THURS AND 2.0 ON
FRI. CONCERN WOULD BE HOW DEEP MIXING WOULD OCCUR INTO THE SHARP
INVERSION SEEN ON ECMWF/GFS. GFS DOES HINT AT THE POTENTIAL FOR A
STRATUS DECK WILL MOISTURE TRAPPED BELOW THE INVERSION...WHICH COULD
KEEP TEMPS COOLER. BUT IF THAT DOESN/T OCCUR...ABUNDANT DRY AIR
ALOFT WOULD LEAD TO A DECENT WARM-UP AND CURRENTLY HAVE VALUES IN
THE UPPER 40S. WITH THE SOUTHWEST WINDS...EXPECT THE HIGHEST TEMPS
/AT LEAST LOWER 50S/ OVER THE DOWNSLOPE AREAS NEAR LK
SUPERIOR...ESPECIALLY IN LOCATIONS LACKING SNOW COVER.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
A LOW PRESSURE SYSTEM APPROACHING THE GREAT LAKES TODAY WILL BRING
LOWERING CIGS/VSBYS AS SNOW DEVELOPS TOWARDS AFTERNOON. THE SNOW
SHOULD FALL HEAVY AT TIMES...ESPECIALLY AT KIWD/KSAW...WHICH COULD
PRODUCE LIFR CIGS/VSBYS. AT THIS TIME...IT APPEARS THE HEAVIEST SNOW
WILL FALL BETWEEN 21Z AND 04Z. THE LOW WILL QUICKLY EXIT
OVERNIGHT...ALLOWING CIGS/VSBYS TO RISE...ALTHOUGH THERE WILL BE SOME
LINGERING LAKE EFFECT SNOW THROUGH DAYBREAK TOMORROW.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A LOW PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS THIS MORNING TO
NORTHERN LOWER MICHIGAN TONIGHT WILL BRING INCREASING NORTH TO
NORTHEAST WINDS TODAY INTO TONIGHT. THERE COULD BE A FEW NORTHERLY
GALE FORCE GUSTS TO 35KTS WITH THE PASSAGE OF THE LOW
TONIGHT...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WITH THE
FAST EXIT OF THE LOW ON SUNDAY...EXPECT WINDS TO QUICKLY DIMINISH AS
HIGH PRESSURE SETTLES OVER LK SUPERIOR. THIS HIGH WILL REMAIN OVER
THE GREAT LAKES THROUGH THE FIRST HALF OF THE WORK WEEK...AS ANOTHER
LOW MOVES THROUGH THE OHIO RIVER VALLEY TUESDAY INTO WEDNESDAY. WEAK
SFC TROUGH MOVING THROUGH ONTARIO ON MON COULD PRODUCE A FEW
SOUTHWEST GUSTS OF 25-30KTS OVER NRN LK SUPERIOR...OTHERWISE EXPECT
WINDS TO STAY BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ006.
WINTER STORM WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO
7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-004-005-009.
WINTER WEATHER ADVISORY FROM 1 PM EST /NOON CST/ THIS AFTERNOON
TO 3 AM EST /2 AM CST/ SUNDAY FOR MIZ001-003-010-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
EXTENDED...SRF
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
542 AM EST SAT NOV 19 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS AND A FLAT RIDGE OVER THE EAST RESULTING IN
SW FLOW FROM THE CNTRL ROCKIES TO THE UPPER GREAT LAKES. A GROWING
AREA OF COLDER CLOUD TOPS WAS DEVELOPING OVER THE NRN PLAINS IN
ADVANCE OF A STRONG SHORTWAVE TROUGH OVER SRN WY INTO NRN CO. AT THE
SFC...A TROUGH/FRONT EXTENDED FROM CNTRL UPPER MI THROUGH CNTRL WI
AND NE IA TO LOW PRES OVER WRN KS. RADARS INDICATED SNOW DEVELOPING
OVER SD ALIGNED WITH STRONG 700-600 MB FGEN.
&&
.DISCUSSION...
TODAY AND TONIGHT...MODELS WERE IN REASONABLY GOOD AGREEMENT WITH
THE TRACK OF THE LOW AND MAIN MID/UPPER LEVEL FEATURES. THE CNTRL
PLAINS LOW IS EXPECTED TO MOVE QUICKLY TO SW WI BY 00Z/SUN AND INTO
NRN LAKE HURON BY 06Z. A PERIOD OF STRONG MID/UPPER LEVEL FORCING IS
EXPECTED WITH THIS SYSTEM AS A COUPLED UPPER LEVEL JET STRUCTURE
PROVIDES STRONG UPPER LEVEL DIV AND INDUCES STRONG MID LEVEL FGEN.
THE NAM AND GFS HAVE BEEN CONSISTENT WITH THE POSITION OF THE
700-600 MB FGEN AND THE ASSOCIATED BAND OF STRONG ASCENT. THIS SHOULD
PLACE THE HEAVIER BAND OF PCPN FROM NEAR IWD TO MQT. MDL QPF AMOUNTS
OF 0.30 TO 0.50 INCHES SEEMS ON TRACK GIVEN THE AVAILABILITY OF 4
G/KG IN THE 290K-295 LAYER ( NEAR 700 MB). ALTHOUGH THE DGZ IS
EXPECTED TO BE RELATIVELY HIGH FROM ABOUT 10K TO 15K FT...IT
COINCIDES WITH THE STRONGER UPWARD MOTION SO THAT AVERAGE SNOW/WATER
RATIO VALUES TO AT LEAST 14/1 ARE EXPECTED DURING THE PERIOD OF
HEAVIER SNOW. THIS WOULD RESULT IN SNOWFALL AMOUNTS GENERALLY IN THE
4 TO 6 INCH RANGE. LAKE AND UPSLOPE TERRAIN ENHANCEMENT WITH BACKING
WINDS FROM NE TO N NEAR IWD AND MQT SHOULD BOOST SNOWFALL AMOUNTS BY
SEVERAL INCHES EVEN THOUGH THE STRONGER SYNOPTIC LIFT MOVES OFF TO
THE ENE QUICKLY BTWN 00Z-06Z. SO...UPGRADED WINTER WX ADVISORIES IN
THOSE LOCATIONS TO WARNINGS WHERE LCL AMOUNTS IN THE 6 TO 8 INCH
RANGE ARE EXPECTED. WITH A LATER CHANGEOVER TO SNOW IN ALGER COUNTY
WITH FCST SNOWFALL IN THE 2 TO 4 INCH RANGE...A WINTER WX ADVY WAS
ALSO POSTED.
THE RAIN SNOW LINE FROM ABOUT P53 TO JUST SE OF IMT THIS AFTERNOON
AND EARLY EVENING...BASED ON 00Z NAM CRITICAL THICKNESS AND WET-BULB
ZERO HEIGHTS...WILL SHIFT QUICKLY TO THE SE THIS EVENING AS THE LOW
MOVES EAST OF THE REGION. SO...SNOWFALL AMOUNTS OF AN INCH OR TWO
ARE ALSO POSSIBLE OVER THE SOUTH AND EAST.
SUNDAY....N TO NW WINDS AND 850 MB TEMPS AROUND -10C/-11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES SHOULD END.
MONDAY...THE COMBINATION OF WAA AND A WEAK SHORTWAVE TROUGH MOVING
NEAR THE CANADA BORDER COULD BRING SOME LIGHT SNOW TO THE NRN GREAT
LAKES. HOWEVER...MOST OF THE PCPN WITH THIS SYSTEM SHOULD REMAIN
NORTH OF THE CWA...PER ECMWF/NAM.
FOR THE EXTENDED...
OVERALL...FAIRLY QUIET EXTENDED PERIOD PCPN WISE WITH WARM TEMPS THE
MAIN STORY LATE IN THE PERIOD. WEAK SHORTWAVE SLIDES ACROSS THE AREA
ON TUES INTO TUES NIGHT. UNCERTAINTY IN AMNT OF H850-700
MOISTURE...WITH MOST OF IT LOCATED IN SRN ONTARIO...SO WILL GO WITH
A DRY FORECAST FOR NOW. THEN STRONG RIDGE DEVELOPING OVER THE NRN
ROCKIES AT THE BEGINNING OF THE WEEK IS EXPECTED TO SHIFT EAST AND
OVER THE GREAT LAKES AREA ON WEDNESDAY AND REMAIN THROUGH FRI. THIS
WILL LEAD TO A WARM UP FOR THANKSGIVING DAY AND BLACK FRIDAY...WITH
HIGHS APPROACHING RECORD VALUES. SEVERAL FACTORS THAT COULD DISRUPT
THE WARM TEMPS...STRENGTH OF THE INVERSION...IF STRATUS DECK
DEVELOPS AND LINGERING SNOW COVER. H850 TEMPS RISE TOWARDS 8-10C ON
THURS AND REMAIN AROUND 7-8C ON FRI. THIS CREATES H850 TEMP
STANDARDIZED ANOMALIES THAT WILL APPROACH 2.5 FOR THURS AND 2.0 ON
FRI. CONCERN WOULD BE HOW DEEP MIXING WOULD OCCUR INTO THE SHARP
INVERSION SEEN ON ECMWF/GFS. GFS DOES HINT AT THE POTENTIAL FOR A
STRATUS DECK WILL MOISTURE TRAPPED BELOW THE INVERSION...WHICH COULD
KEEP TEMPS COOLER. BUT IF THAT DOESN/T OCCUR...ABUNDANT DRY AIR
ALOFT WOULD LEAD TO A DECENT WARM-UP AND CURRENTLY HAVE VALUES IN
THE UPPER 40S. WITH THE SOUTHWEST WINDS...EXPECT THE HIGHEST TEMPS
/AT LEAST LOWER 50S/ OVER THE DOWNSLOPE AREAS NEAR LK
SUPERIOR...ESPECIALLY IN LOCATIONS LACKING SNOW COVER.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
MAIN CONCERN FOR THE TAF PERIOD WILL BE THE LOW PRESSURE SYSTEM
CROSSING EASTERN UPPER MICHIGAN SATURDAY AFTERNOON THROUGH SUNDAY
MORNING. CONDITIONS WILL CONTINUE TO DETERIORATE AS THE LOW DRAWS
CLOSER AND GO TO MVFR AT KCMX AND KIWD OVERNIGHT AND REMAIN VFR AT
KSAW TONIGHT. CONDITIONS WILL RAPIDLY DETERIORATE ON SATURDAY AS THE
SNOW COMES IN IN THE AFTERNOON AND WILL DROP TO IFR/LIFR AT KIWD AND
KCMX AND COULD DROP AS LOW AS VLIFR AT KSAW. UPSLOPE NORTH TO
NORTHEAST WINDS WILL ALSO HELP THE SNOW AND LOW CIGS AT KSAW AND
KIWD SATURDAY INTO SAT NIGHT. THE LIGHT TO MODERATE SNOW SHOULD LAST
ABOUT 8 HOURS OR SO BEFORE THE MOISTURE MOVES OUT LATE SATURDAY
NIGHT.
&&
.MARINE /FOR THE 4AM LAKE SUPERIOR FORECAST ISSUANCE/...
A LOW PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS THIS MORNING TO
NORTHERN LOWER MICHIGAN TONIGHT WILL BRING INCREASING NORTH TO
NORTHEAST WINDS TODAY INTO TONIGHT. THERE COULD BE A FEW NORTHERLY
GALE FORCE GUSTS TO 35KTS WITH THE PASSAGE OF THE LOW
TONIGHT...MAINLY OVER CENTRAL AND EASTERN LAKE SUPERIOR. WITH THE
FAST EXIT OF THE LOW ON SUNDAY...EXPECT WINDS TO QUICKLY DIMINISH AS
HIGH PRESSURE SETTLES OVER LK SUPERIOR. THIS HIGH WILL REMAIN OVER
THE GREAT LAKES THROUGH THE FIRST HALF OF THE WORK WEEK...AS ANOTHER
LOW MOVES THROUGH THE OHIO RIVER VALLEY TUESDAY INTO WEDNESDAY. WEAK
SFC TROUGH MOVING THROUGH ONTARIO ON MON COULD PRODUCE A FEW
SOUTHWEST GUSTS OF 25-30KTS OVER NRN LK SUPERIOR...OTHERWISE EXPECT
WINDS TO STAY BELOW 25KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST
SUNDAY FOR MIZ006.
WINTER STORM WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO
7 AM EST /6 AM CST/ SUNDAY FOR MIZ002-004-005-009.
WINTER WEATHER ADVISORY FROM 1 PM EST /NOON CST/ THIS AFTERNOON
TO 3 AM EST /2 AM CST/ SUNDAY FOR MIZ001-003-010-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
EXTENDED...SRF
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1138 AM CST SAT NOV 19 2011
.AVIATION...18Z TAF ISSUANCE...
NARROW BAND OF SNOW SHOWERS CONTINUES TO DEVELOP ACROSS THE SRN
HALF OF THE FORECAST AREA FROM AROUND BRD EASTWARD TO ASH/HYR.
THESE SHSN ARE PRODUCING PERIODS OF IFR/LIFR CIGS AND VSBYS WITHIN
THE MDT/HVY SNOW SHOWERS. THIS LINE OF SNOW WILL LINGER ACROSS THE
REGION AND SLOWLY MOVE TO THE EAST THIS AFTERNOON. OCCASIONAL LIFR
VSBYS ARE POSSIBLE FROM BRD TO DLH TO HYR. INL AND HIB SHOULD STAY
MOSTLY DRY UNDER LOW-END MVFR OR HIGH-END IFR CIGS. CONDITIONS
IMPROVE TONIGHT FOR ALL TERMINALS EXCEPT HYR...WHICH STAYS
BLANKETED UNDER THE LAKE EFFECT CLOUDS. A LOW DECK OF STRATUS
POSSIBLY MOVES THROUGH BY LATE MORNING TOMORROW FROM W TO E. WINDS
REMAIN FAIRLY LIGHT FROM THE N/NW.
&&
.PREV DISCUSSION... /ISSUED 1051 AM CST SAT NOV 19 2011/
UPDATE...REMOVED THE HEADLINES FROM SOUTHERN CASS...CROW
WING...AITKIN...SOUTHERN ST. LOUIS AND CARLTON COUNTIES. LATEST
RUC ANALYSIS...NAM12 AND GEM REG ALL SUPPORT THIS THINKING.
CURRENT RADAR OBS LINE UP WELL WITH RUC 850-700 FRONTOGENESIS MAX
WHICH IS SOUTH OF AFOREMENTIONED HEADLINED AREAS. BEST AXIS OF
HIGHER SNOW TOTALS APPEARS TO BE ACROSS PINE COUNTY IN MN AND
ALL OF NW WI. STILL EXPECTING ABOUT 3 TO 5 INCHES WHERE REMAINING
ADVISORY HEADLINES ARE PLACE. NO CHANGE TO THE WINTER STORM
WARNING FOR ASHLAND AND IRON COUNTIES AS LAKE EFFECT PARAMETERS
COME INTO PLAY LATER.
PREV DISCUSSION... /ISSUED 544 AM CST SAT NOV 19 2011/
AVIATION...12Z TAFS
LOW PRESSURE IN THE CO/KS AREA IS FORECAST TO MOVE TOWARD
SOUTHWEST WI BY THIS EVENING...THEN CONTINUE NORTHEAST TONIGHT
INTO QUEBEC.
HIGH CLOUDS HAVE OVERTAKEN THE REGION...MASKING THE MVFR CEILINGS
THAT COVERED MUCH OF THE NORTHLAND. THERE ARE SOME BREAKS IN THIS
MVFR DECK AS NOTED IN SOME OF THE SURFACE OBSERVATIONS.
OVERALL...MVFR CEILINGS...WITH SOME IFR...ARE EXPECTED INTO THIS
EVENING. MODELS HAVE BEEN SHIFTING THE MAIN AREA OF PRECIPITATION
A BIT FURTHER SOUTH OVER THE PAST COUPLE OF MODEL RUNS.
HOWEVER...CURRENT SATELLITE AND RADAR LOOPS SHOW RETURNS IN AN
AREA OF MID LEVEL FGEN...AND THAT IS FORECAST TO CONTINUE THIS
MORNING...SHIFTING NORTH THROUGH THE DAY. WE EXPECT SNOW TO IMPACT
THE KDLH/KHYR/KBRD TAFS LATER THIS MORNING OR EARLY THIS
AFTERNOON. IT WILL TAKE SOME TIME TO SATURATE THE LOW LEVELS...AS
MUCH OF THE RETURNS ON RADAR WERE NOT HITTING THE GROUND. IFR
VSBYS WILL BE POSSIBLE IN THE SNOW ONCE IT GETS STARTED. THE LOW
IS MOVING OFF QUICKLY...SO THE SNOW SHOULD DIMINISH FROM WEST TO
EAST OVERNIGHT.
PREV DISCUSSION... /ISSUED 348 AM CST SAT NOV 19 2011/
SHORT TERM...TODAY THROUGH SUNDAY
A BAND OF ACCUMULATING SNOWFALL APPEARS TO BE ON TRACK FOR AREAS
ALONG AND SOUTH OF THE HIGHWAY 2 CORRIDOR.
LOW PRESSURE OVER THE CENTRAL ROCKIES WILL QUICKLY EJECT
NORTHEASTWARD EARLY THIS MORNING AND BE OVER EASTERN IOWA LATE
THIS AFTERNOON. REGIONAL RADAR CURRENTLY SHOWS A RELATIVELY NARROW
BAND OF SNOW OVER SOUTH DAKOTA EDGING INTO WEST CENTRAL MINNESOTA.
THE AREAL EXTENT OF THE PRECIPITATION LINES UP WELL WITH THE NAM40
700 MB FRONTOGENESIS AT 09Z. SOME CONCERNS BY 15Z AS THE NAM
DEPICTS THE GREATEST FGEN IN A CORRIDOR FROM BRD TO DLH AND
EASTWARD TO ASX. THEREFORE...STARTED THE WINTER WEATHER ADVISORY
SEVERAL HOURS EARLIER FOR THE SOUTHWESTERN CWA. BY 21Z...ANOTHER
AREA OF FGEN MOVES INTO NORTHWESTERN WISCONSIN...WHERE THE THERMAL
GRADIENT IS STRONGEST. DUE TO THE SPEED OF THIS SYSTEM...EXPECTING
SNOW AMOUNTS IN THE 2 TO 5 INCH RANGE ACROSS THE SOUTHERN HALF OF
THE CWA. THERE WILL LIKELY BE A NARROW CORRIDOR OF SLIGHTLY HIGHER
AMOUNTS SOUTH OF THE TWIN PORTS AND INTO NORTHWESTERN WISCONSIN.
THE SNOW WILL QUICKLY DEPART THE MINNESOTA ZONES BY MIDNIGHT.
LAKE ENHANCEMENT NEAR THE SNOW BELT REGIONS OF ASHLAND AND IRON
COUNTIES WILL ADD TO THE SNOWFALL TOTALS IN THAT AREA. ALSO...A
WINDOW OF OPPORTUNITY EXISTS FOR LAKE EFFECT SNOW SHOWERS BETWEEN
03Z AND 09Z FOR THE GOGEBIC RANGE AS WINDS BECOME NORTHERLY BEHIND
THE DEPARTING LOW PRESSURE SYSTEM. DECREASING CLOUDS AND BELOW
NORMAL TEMPERATURES WILL OVERTAKE THE NORTHLAND ON SUNDAY AS AN
AREA OF SURFACE HIGH PRESSURE DEVELOPS OVER THE RED RIVER VALLEY.
EXTENDED...SUNDAY NIGHT THROUGH FRIDAY.
UPPER FLOW WILL BE FAST ZONAL EARLY IN THE PERIOD...WITH A COUPLE
EMBEDDED SHORTWAVES THROUGH TUESDAY. THE UPPER FLOW WILL AMPLIFY AS
A RIDGE DEVELOPS AND MOVES TOWARD THE REGION WEDNESDAY-THURSDAY. THE
RIDGE WILL PASS EAST OF THE NORTHLAND LATER THURSDAY WITH A TROUGH
OF LOW PRESSURE MOVING IN FOR FRIDAY-SATURDAY. THE GFS AND ECMWF ARE
IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL FLOW. TEMPERATURES
WILL BE WARMING THROUGH NEXT WEEK AS THE RIDGE STARTS TO BUILD
IN...THEN COOL WITH THE TROUGH LATE.
THE FIRST SHORTWAVE WILL BRING SOME LIGHT SNOW/FLURRIES TO PORTIONS
OF THE NORTHLAND AS EARLY AS SUNDAY NIGHT...BUT IT SHOULD EXIT BY
MONDAY AFTERNOON. WE KEPT THE FORECAST DRY WITH THE SECOND SHORTWAVE
ON TUESDAY...AS THE WAVE LOOKS WEAKER AND THERE IS LESS MOISTURE
AVAILABLE. IT SHOULD BE DRY AND WARMER WEDNESDAY AND THURSDAY...WITH
FRIDAY A TRANSITION PERIOD AS THE TROUGH APPROACHES AND TEMPS BEGIN
TO COOL. WE KEPT THE MAJORITY OF THE NORTHLAND DRY ON FRIDAY.
TEMPS SHOULD WARM FROM THE UPPER TWENTIES-MID THIRTIES EARLY IN THE
PERIOD...INTO THE FORTIES WEDNESDAY-FRIDAY.
&&
.POINT TEMPS/POPS...
DLH 30 11 23 17 / 50 10 0 10
INL 21 6 21 9 / 10 10 0 20
BRD 28 8 24 15 / 60 10 0 10
HYR 36 15 27 15 / 80 40 10 10
ASX 35 19 29 16 / 70 50 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR MNZ038.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ001-002-
006>009.
WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR WIZ003-004.
LS...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST SUNDAY
FOR LSZ121-140>148.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
1051 AM CST SAT NOV 19 2011
.UPDATE...REMOVED THE HEADLINES FROM SOUTHERN CASS...CROW
WING...AITKIN...SOUTHERN ST. LOUIS AND CARLTON COUNTIES. LATEST
RUC ANALYSIS...NAM12 AND GEM REG ALL SUPPORT THIS THINKING.
CURRENT RADAR OBS LINE UP WELL WITH RUC 850-700 FRONTOGENESIS MAX
WHICH IS SOUTH OF AFOREMENTIONED HEADLINED AREAS. BEST AXIS OF
HIGHER SNOW TOTALS APPEARS TO BE ACROSS PINE COUNTY IN MN AND
ALL OF NW WI. STILL EXPECTING ABOUT 3 TO 5 INCHES WHERE REMAINING
ADVISORY HEADLINES ARE PLACE. NO CHANGE TO THE WINTER STORM
WARNING FOR ASHLAND AND IRON COUNTIES AS LAKE EFFECT PARAMETERS
COME INTO PLAY LATER.
&&
.PREV DISCUSSION... /ISSUED 544 AM CST SAT NOV 19 2011/
AVIATION...12Z TAFS
LOW PRESSURE IN THE CO/KS AREA IS FORECAST TO MOVE TOWARD
SOUTHWEST WI BY THIS EVENING...THEN CONTINUE NORTHEAST TONIGHT
INTO QUEBEC.
HIGH CLOUDS HAVE OVERTAKEN THE REGION...MASKING THE MVFR CEILINGS
THAT COVERED MUCH OF THE NORTHLAND. THERE ARE SOME BREAKS IN THIS
MVFR DECK AS NOTED IN SOME OF THE SURFACE OBSERVATIONS.
OVERALL...MVFR CEILINGS...WITH SOME IFR...ARE EXPECTED INTO THIS
EVENING. MODELS HAVE BEEN SHIFTING THE MAIN AREA OF PRECIPITATION
A BIT FURTHER SOUTH OVER THE PAST COUPLE OF MODEL RUNS.
HOWEVER...CURRENT SATELLITE AND RADAR LOOPS SHOW RETURNS IN AN
AREA OF MID LEVEL FGEN...AND THAT IS FORECAST TO CONTINUE THIS
MORNING...SHIFTING NORTH THROUGH THE DAY. WE EXPECT SNOW TO IMPACT
THE KDLH/KHYR/KBRD TAFS LATER THIS MORNING OR EARLY THIS
AFTERNOON. IT WILL TAKE SOME TIME TO SATURATE THE LOW LEVELS...AS
MUCH OF THE RETURNS ON RADAR WERE NOT HITTING THE GROUND. IFR
VSBYS WILL BE POSSIBLE IN THE SNOW ONCE IT GETS STARTED. THE LOW
IS MOVING OFF QUICKLY...SO THE SNOW SHOULD DIMINISH FROM WEST TO
EAST OVERNIGHT.
PREV DISCUSSION... /ISSUED 348 AM CST SAT NOV 19 2011/
SHORT TERM...TODAY THROUGH SUNDAY
A BAND OF ACCUMULATING SNOWFALL APPEARS TO BE ON TRACK FOR AREAS
ALONG AND SOUTH OF THE HIGHWAY 2 CORRIDOR.
LOW PRESSURE OVER THE CENTRAL ROCKIES WILL QUICKLY EJECT
NORTHEASTWARD EARLY THIS MORNING AND BE OVER EASTERN IOWA LATE
THIS AFTERNOON. REGIONAL RADAR CURRENTLY SHOWS A RELATIVELY NARROW
BAND OF SNOW OVER SOUTH DAKOTA EDGING INTO WEST CENTRAL MINNESOTA.
THE AREAL EXTENT OF THE PRECIPITATION LINES UP WELL WITH THE NAM40
700 MB FRONTOGENESIS AT 09Z. SOME CONCERNS BY 15Z AS THE NAM
DEPICTS THE GREATEST FGEN IN A CORRIDOR FROM BRD TO DLH AND
EASTWARD TO ASX. THEREFORE...STARTED THE WINTER WEATHER ADVISORY
SEVERAL HOURS EARLIER FOR THE SOUTHWESTERN CWA. BY 21Z...ANOTHER
AREA OF FGEN MOVES INTO NORTHWESTERN WISCONSIN...WHERE THE THERMAL
GRADIENT IS STRONGEST. DUE TO THE SPEED OF THIS SYSTEM...EXPECTING
SNOW AMOUNTS IN THE 2 TO 5 INCH RANGE ACROSS THE SOUTHERN HALF OF
THE CWA. THERE WILL LIKELY BE A NARROW CORRIDOR OF SLIGHTLY HIGHER
AMOUNTS SOUTH OF THE TWIN PORTS AND INTO NORTHWESTERN WISCONSIN.
THE SNOW WILL QUICKLY DEPART THE MINNESOTA ZONES BY MIDNIGHT.
LAKE ENHANCEMENT NEAR THE SNOW BELT REGIONS OF ASHLAND AND IRON
COUNTIES WILL ADD TO THE SNOWFALL TOTALS IN THAT AREA. ALSO...A
WINDOW OF OPPORTUNITY EXISTS FOR LAKE EFFECT SNOW SHOWERS BETWEEN
03Z AND 09Z FOR THE GOGEBIC RANGE AS WINDS BECOME NORTHERLY BEHIND
THE DEPARTING LOW PRESSURE SYSTEM. DECREASING CLOUDS AND BELOW
NORMAL TEMPERATURES WILL OVERTAKE THE NORTHLAND ON SUNDAY AS AN
AREA OF SURFACE HIGH PRESSURE DEVELOPS OVER THE RED RIVER VALLEY.
EXTENDED...SUNDAY NIGHT THROUGH FRIDAY.
UPPER FLOW WILL BE FAST ZONAL EARLY IN THE PERIOD...WITH A COUPLE
EMBEDDED SHORTWAVES THROUGH TUESDAY. THE UPPER FLOW WILL AMPLIFY AS
A RIDGE DEVELOPS AND MOVES TOWARD THE REGION WEDNESDAY-THURSDAY. THE
RIDGE WILL PASS EAST OF THE NORTHLAND LATER THURSDAY WITH A TROUGH
OF LOW PRESSURE MOVING IN FOR FRIDAY-SATURDAY. THE GFS AND ECMWF ARE
IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL FLOW. TEMPERATURES
WILL BE WARMING THROUGH NEXT WEEK AS THE RIDGE STARTS TO BUILD
IN...THEN COOL WITH THE TROUGH LATE.
THE FIRST SHORTWAVE WILL BRING SOME LIGHT SNOW/FLURRIES TO PORTIONS
OF THE NORTHLAND AS EARLY AS SUNDAY NIGHT...BUT IT SHOULD EXIT BY
MONDAY AFTERNOON. WE KEPT THE FORECAST DRY WITH THE SECOND SHORTWAVE
ON TUESDAY...AS THE WAVE LOOKS WEAKER AND THERE IS LESS MOISTURE
AVAILABLE. IT SHOULD BE DRY AND WARMER WEDNESDAY AND THURSDAY...WITH
FRIDAY A TRANSITION PERIOD AS THE TROUGH APPROACHES AND TEMPS BEGIN
TO COOL. WE KEPT THE MAJORITY OF THE NORTHLAND DRY ON FRIDAY.
TEMPS SHOULD WARM FROM THE UPPER TWENTIES-MID THIRTIES EARLY IN THE
PERIOD...INTO THE FORTIES WEDNESDAY-FRIDAY.
&&
.POINT TEMPS/POPS...
DLH 30 11 23 17 / 50 10 0 10
INL 20 6 21 9 / 10 10 0 20
BRD 28 8 24 15 / 60 10 0 10
HYR 36 15 27 15 / 80 40 10 10
ASX 35 19 29 16 / 70 50 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 PM CST THIS EVENING FOR MNZ038.
WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ001-002-
006>009.
WINTER STORM WARNING UNTIL 6 AM CST SUNDAY FOR WIZ003-004.
LS...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST SUNDAY
FOR LSZ121-140>148.
&&
$$
SHORT TERM...GSF
LONG TERM....TENTINGER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
325 PM EST SAT NOV 19 2011
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE THIS WEEKEND AND INTO EARLY NEXT
WEEK. TEMPERATURES WILL BEGIN TO WARM OVER THE WEEKEND AS SOUTHERLY
WINDS DEVELOP. A COLD FRONT WILL MOVE THROUGH WEDNESDAY. COOLER
WEATHER IS EXPECTED LATE NEXT WEEK AS HIGH PRESSURE BUILDS IN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SATURDAY...SURFACE TROUGH REMAINING JUST TO THE EAST OF
LOCAL COASTAL WATERS WILL SHIFT FARTHER WEST CLOSER TO THE CAROLINA
COAST THROUGH THIS EVENING BEFORE DISSIPATING OVERNIGHT. LIGHT
NORTHEAST FLOW ON WEST SIDE OF TROUGH WILL SHIFT MORE EASTERLY
ESPECIALLY ALONG THE COAST AS IT SHIFTS CLOSER. OVERALL WEAK
GRADIENT WITH WINDS REMAINING 5 MPH OR LESS MOST PLACES AT THE
SURFACE. RUC SOUNDINGS SHOWING AN OVERALL WARMING AND DRYING OF THE
COLUMN AT LOW LEVELS AS WARMER AIR MAKES ITS WAY IN ALOFT AND MIXING
OCCURS THROUGH TODAY...BUT DECENT ON SHORE SE FLOW AT H85 CONTINUING
TO BRING MOISTURE AND SOME CLOUDS ON SHORE MAINLY OVER SC.
ON SHORE FLOW WILL CAPTURE SOME OF THE MARINE INFLUENCE CONTINUING
TO BRING HIGHER DEWPOINT AIR INLAND AS WINDS SHIFT BECOMING MORE
EASTERLY. THE DEWPOINTS ALONG THE COAST WILL REMAIN IN THE 50S
THROUGH MOST OF THE NIGHT WHILE INLAND DEWPOINTS WILL BE IN THE MID
40S. WAA WILL CONTINUE WITH SW FLOW ABOVE THE SURFACE. 850 TEMPS
AROUND 4 TO 5 C THIS MORNING WILL RISE UP TO AROUND 8C BY DAYBREAK
ON SUNDAY. LOW LEVEL FLOW WILL CONTINUE TO COME AROUND FROM S-SE TO
SW OVERNIGHT WHILE SURFACE WINDS BECOME VERY LIGHT AND VARIABLE TO
NEAR CALM. CLOUDS ASSOCIATED WITH COASTAL TROUGH MAY MOVE ON SHORE
THROUGH THIS EVENING AS H85 FLOW CONTINUES OUT OF THE SE BEFORE
SHIFTING TO S-SW OVERNIGHT. THE SFC TROUGH AXIS SHIFTS A LITTLE
FARTHER WEST BUT DISSIPATES OVERNIGHT AS HIGH PRESSURE CONTINUES TO
RIDGE BACK INTO THE CAROLINAS. OVERALL VERY WEAK PRESSURE PATTERN
EXPECTED WITH CALM WINDS. FOR NOW WILL KEEP MOST CLOUDS OUT OF THE
EQUATION ALLOWING FOR MORE IDEAL RADIATIONAL COOLING AND DENSER FOG
THREAT...BUT THE EXTENT OF FOG WILL DEPEND ON HOW MUCH CLOUD COVER
THERE WILL BE...WHICH WILL BE THE FORECAST CHALLENGE OVERNIGHT.
TEMPS WILL DROP OFF AS WE RADIATE OUT OVER MOST PLACES BUT
WAA...INCREASED LOW LEVEL MOISTURE AND SOME CLOUDS WILL KEEP TEMPS
AND SFC DEWPOINTS HIGHER THAN PREVIOUS NIGHTS. FORECAST LOWS WILL
THEREFORE DROP TO THE LOW TO MID 40S MOST PLACES INLAND AND CLOSER
TO 50 ALONG THE COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...HIGH PRESSURE WILL SHIFT OFF THE COAST SUNDAY
AND RESULT IN WARMING S-SW FLOW THROUGH THE PERIOD. THERE WILL BE
SOME INCREASE IN CLOUDS MONDAY NIGHT AS A FRONTAL SYSTEM APPROACHES
FROM THE WEST...OTHERWISE FAIR WEATHER IS EXPECTED. HIGHS WILL
MODERATE SLIGHTLY EACH DAY...MODERATING FROM THE LOWER 70S SUNDAY TO
THE MIDDLE 70S MONDAY. LOWS SUNDAY NIGHT WILL FALL TO THE UPPER 40S
TO LOWER 50S WITH MID TO UPPER 50S EXPECTED MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...DAYBREAK TUESDAY AN UPPER TROUGH AXIS WILL
BE POSITIONED ROUGHLY ALONG THE MISSISSIPPI VALLEY...WITH SURFACE
HIGH PRESSURE SITUATED OFFSHORE OF THE CAROLINAS. EARLY TUESDAY A
WARM FRONT WILL RESIDE NORTH OF THE AREA...SO NO MENTIONABLE POP
VALUES PLANNED UNTIL TUESDAY NIGHT AS A COLD FRONT BREAKS EAST OF
THE APPALACHIAN MOUNTAINS. FRONTAL PASSAGE BASED ON AN GFS/ECMWF
CONSENSUS SOMETIME WEDNESDAY EITHER SIDE OF MIDDAY. SHRA TAPERING
OFF AND COLD AIR ADVECTION REGIME WEDNESDAY NIGHT AND A CLEARING
TREND INTO EARLY THURSDAY.
HENCE A DRY FORECAST DAY 6/7 FRI/SAT ALTHOUGH WE MAY EXPECT RETURN
FLOW NEXT WEEKEND AS THE PATTERN SHOWS A PROGRESSIVE NATURE.
TEMPERATURES 7-10 DEG F ABOVE NORMAL TUE/WED IN WARM SECTOR OF THE
APPROACHING FRONT...KNOCKED DOWN TO NORMAL DIURNAL TEMPERATURE
CURVES FOR NOVEMBER THU/FRI...THEN WARMING INTO NEXT SATURDAY.
THANKSGIVING DAY LOOKS SUNNY AND COOL. THE COLDEST MORNING IN THE
EXTENDED FORECAST LOOKS TO BE FRIDAY MORNING AS THE HIGH SETTLES
OVERHEAD BENEATH A CLEAR DOME...SO FREEZING TEMPS POSSIBLE THEN.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...MODERATE CONFIDENCE THROUGH THE VALID PERIOD DUE TO
VARYING CLOUDS TODAY...AND FOG THREAT OVERNIGHT.
VISIBLE IMAGERY CONTINUING TO SHOW MID LEVEL CLOUD COVER INLAND WITH
NOTHING AT THE COAST. AMPLE STRATOCU OFFSHORE IS NOT MAKING IT
WESTWARD...BUT STILL EXPECT SOME CU ADVECTING ONSHORE AS WINDS TURN
TO THE SE AND PERSIST THROUGH TONIGHT. INLAND TERMINALS WILL
CONTINUE BKN MID LEVEL CU CIGS THROUGH NIGHTFALL. ATTM...AM
DISCOUNTING THE ENTIRELY OVERAGGRESSIVE NAM WHICH STILL WANTS MVFR
STRATUS ALONG THE COAST...AND WILL KEEP VFR THROUGH TONIGHT. WINDS
WILL BE LIGHT...BECOMING SE AT LESS THAN 10 KTS.
GUIDANCE STILL DEPICTING WIDESPREAD IFR FOG OVERNIGHT...AND WITH
LESS CLOUD COVER NOW EXPECTED BUT SE WINDS RAISING THE TD/S...FOG
NOW APPEARS LIKELY. IF SKY CONDITIONS CLEAR AS DEPICTED ON NON-NAM
FORECAST SOUNDINGS...NEARLY IDEAL RADIATIONAL COOLING WILL EXIST
SINCE WINDS SHOULD FULLY DECOUPLE. THIS COMBINED WITH THE FACT THAT
MINS SHOULD EXCEED THEIR CROSSOVER TEMPS MEANS THAT IFR FOG IS
EXPECTED AT ALL TERMINALS. HAVE INTRODUCED IFR EVERYWHERE...AND WILL
GET MORE SPECIFIC WITH LATER UPDATES SINCE LIFR IS POSSIBLE. VERY
LIGHT WINDS CONTINUING ON SUNDAY WILL ONLY SLOWLY LIFT FOG INTO
STRATUS...ESPECIALLY INLAND...BUT VFR IS EXPECTED BY LATE MORNING.
EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG MONDAY/TUESDAY MORNINGS AND
ISOLATED SHOWERS DURING THE AFTERNOONS. SHOWERS ASSOCIATED WITH A
COLD FRONT MAY IMPACT THE TERMINALS ON WEDNESDAY. VFR THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SATURDAY...WINDS WILL SHIFT AROUND TO THE E-SE THROUGH
THIS EVENING AS TROUGH JUST TO THE EAST OF LOCAL WATERS SHIFTS A
LITTLE FARTHER WEST THROUGH THIS EVENING BEFORE DISSIPATING BY
DAYBREAK. OVERALL WEAK HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE
CAROLINAS AS IT SHIFTS FARTHER OFF SHORE OVERNIGHT. THEREFORE EXPECT
SFC WINDS TO BECOME LIGHT WEST OR VARIABLE OVERNIGHT AROUND 5 TO 10
KTS. PATCHY CU MAY CONTINUE TO MOVE OVER THE LOCAL WATERS OR DEVELOP
ALONG THE SFC TROUGH. CAN NOT RULE OUT A SPRINKLE AS TROUGH MOVES
SLIGHTLY CLOSER TO THE COAST THIS EVENING BEFORE WEAKENING. SLIGHTLY
LONGER PERIOD E-NE SWELL COMING AROUND THE HIGH PRESSURE WILL
COMBINE WITH LOCALLY MINIMAL WIND WAVE TO PRODUCE SEAS IN THE 2 TO 3
FT RANGE MOST WATERS WITH A FEW 4 FTERS IN OUTER WATERS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...LIGHT AND VARIABLE WINDS SUNDAY WILL BECOME S
TO SW DURING THE AFTERNOON AND CONTINUE THROUGH MONDAY NIGHT.
SPEEDS OF 15 KT OR LESS ARE EXPECTED THROUGH THE PERIOD WITH SEAS
WILL OF 2 TO 4 FT.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...TUESDAY THROUGH THURSDAY LOOKS UNSETTLED
AND ROUGH ON THE 0-20NM WATERS...PRIMARILY DUE TO A COLD FRONTAL
PASSAGE WEDNESDAY. PRE-FRONT SW WINDS LATE TUESDAY...AND POST-
FRONT NW WINDS LATE WED MAY BOTH REQUIRE AN ADVISORY...HENCE WE
MAY SEE AN ADVISORY FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT
BASED ON CURRENT TIMING AND STRENGTH OF THE APPROACHING FRONT.
ADDITIONALLY...WE MAY SEE A FEW TSTMS OVER THE WATERS WEDNESDAY.
THE SEA SPECTRUM TUE-THU WILL BE MARKED BY E WAVES 2-3 FEET AT 10
SECONDS...WITH GROWING SSW WIND-WAVES/BUILDING SOUTHERLY CHOP AND
SLOP. EXPECT A WIND-SHIFT TO NW WED AFTERNOON...CHANGING DIRECTION
OF THE SHORT PERIOD WAVES. THE COLD AIR ADVECTION BEHIND THE FRONT
WILL BRING NW WIND GUSTS TO 25-30 KNOTS WEDNESDAY AFTERNOON AND
NIGHT. THURSDAY OR THANKSGIVING DAY...A DAY OF IMPROVEMENT BUT A
BIT ROUGH IN THE MORNING FROM NNW WINDS...HIGHEST OFFSHORE. NEAR
SHORE CONDITIONS WILL IMPROVE THE QUICKEST EARLY THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...31
LONG TERM...MJC
AVIATION...JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
126 PM EST SAT NOV 19 2011
.SYNOPSIS...
HIGH PRESSURE OVERHEAD WILL MOVE OFFSHORE THIS WEEKEND AND INTO
EARLY NEXT WEEK. TEMPERATURES WILL BEGIN TO WARM OVER THE WEEKEND
AS SOUTHERLY WINDS DEVELOP. A COLD FRONT WILL MOVE THROUGH
WEDNESDAY. COOLER WEATHER IS EXPECTED LATE NEXT WEEK AS HIGH
PRESSURE BUILDS IN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM SATURDAY...COASTAL TROUGH REMAINING JUST TO THE EAST OF
LOCAL COASTAL WATERS WITH LIGHT NORTHEAST FLOW ON WEST SIDE OF
TROUGH OVER LAND AREAS. OVERALL GRADIENT IS WEAK WITH WINDS
REMAINING 5 MPH OR LESS MOST PLACES AT THE SURFACE. RUC SOUNDINGS
SHOWING AN OVERALL WARMING AND DRYING OF THE COLUMN AT LOW LEVELS
AS WARMER AIR MAKES IT WAY IN ALOFT AND MIXING OCCURS THROUGH
TODAY. EXPECT ONLY LINGERING PATCHES OF CLOUDS THROUGH THIS
AFTERNOON. MOST AREAS WILL EXPERIENCE PARTLY TO MOSTLY SUNNY
SKIES. NE FLOW WILL CAPTURE SOME OF THE MARINE INFLUENCE BRINGING
HIGH DEWPOINT AIR IN. THE DEWPOINTS ALONG THE COAST SHOULD REACH
UP INTO THE MID 50S WHILE INLAND DEWPOINTS IN THE 30S WILL RISE
INTO THE MID 40S BY THE END OF THE DAY. WAA WILL CONTINUE WITH SW
FLOW ABOVE THE SURFACE. 850 TEMPS AROUND 4 TO 5 C THIS MORNING
WILL RISE UP TO AROUND 8C BY DAYBREAK ON SUNDAY. WILL KEEP MAX
TEMPS IN THE MID 60S
SURFACE FLOW WILL CONTINUE TO COME AROUND FROM THE NE TO E AND
EVENTUALLY SE. CLOUDS ASSOCIATED WITH COASTAL TROUGH MAY MOVE ON
SHORE THROUGH THIS EVENING AS THE TROUGH AXIS SHIFTS A LITTLE
FARTHER WEST. THIS TROUGH DISSIPATES OVERNIGHT AS HIGH PRESSURE
CONTINUES TO RIDGE BACK INTO THE CAROLINAS. OVERALL VERY WEAK
PRESSURE PATTERN EXPECTED WITH CALM WINDS EXPECTED. FOR NOW WILL
KEEP MOST CLOUDS OUT OF THE EQUATION ALLOWING FOR MORE IDEAL
RADIATIONAL COOLING AND DENSER FOG THREAT. TEMPS WILL DROP OFF BUT
WAA AND INCREASED LOW LEVEL MOISTURE WILL KEEP SFC DEWPOINTS
ALLOWING FOR LESS OF A TEMP DROP THAN PREVIOUS NIGHTS. FORECAST
LOWS WILL BE LOW TO MID 40S MOST PLACES AND CLOSER TO 50 ALONG THE
COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE RIDGE AXIS OVER THE AREA SUN SHIFTS
SOUTHEAST OF THE AREA MON. PATTERN ALOFT WILL TRANSITION FROM WEAK
RIDGING SUN TO ZONAL FLOW MON INTO MON NIGHT AS SHORTWAVE TROUGH
MOVES FROM THE SOUTHWEST INTO THE MID MISSISSIPPI VALLEY. BACKDOOR
COLD FRONT WILL STALL WELL NORTH OF THE AREA MON NIGHT. PRECIP DOES
NOT LOOK LIKE MUCH OF A CONCERN AT THIS POINT BUT INCREASING MID AND
UPPER LEVEL MOISTURE AHEAD OF AFOREMENTIONED WAVE WILL LEAD TO AN
INCREASE IN CLOUD COVER LATE MON AND MON NIGHT.
PROXIMITY TO RIDGE AXIS SUN WILL KEEP FLOW LIGHT...THOUGH GENERALLY
WITH A SOUTHERLY COMPONENT. ALONG THE COAST SEA BREEZE MAY TEMPER
HIGHS A DEGREE OR TWO. REGARDLESS TEMPERATURES ACROSS THE REGION
WILL BE ABOVE CLIMO SUN AND SUN NIGHT. SOUTHWEST FLOW BECOMES MORE
ESTABLISHED MON HELPING PUSH HIGHS INTO THE MID 70S ACROSS MUCH OF
THE AREA. INCREASE IN CLOUD COVER MON AFTERNOON MAY TEMPER HIGHS
ACROSS THE NORTHERN TIER OF COUNTIES. ABOVE CLIMO TEMPS CONTINUE MON
NIGHT WITH SOUTHWEST FLOW AND INCREASING CLOUD COVER HOLDING HIGHS
IN THE MID TO UPPER 50S.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...MAIN FEATURE FOR THE PERIOD WILL BE COLD FRONT
CROSSING THE AREA WED. SURFACE LOW AND ASSOCIATED OPEN 5H WAVE WILL
TRACK NORTH OF THE AREA...MOVING INTO THE OH VALLEY TUE NIGHT. LOW
WILL BE JUST EAST OF SOUTHERN NEW ENGLAND WED MORNING WITH COLD
FRONT EXTENDING SOUTHWEST THROUGH CENTRAL NC/SC AND INTO GA. AHEAD
OF THE FRONT TUE AND TUE NIGHT WEAK SUBSIDENCE AT THE TOP OF NARROW
5H RIDGE INDUCE BY 5H TROUGH WILL HELP DRY MID LEVELS AND SUPPRESS
UPWARD MOTION. NARROW BAND OF DEEP MOISTURE MAY PRODUCE A BROKEN
LINE OF CONVECTION...BUT LIMITED INSTABILITY WILL IMPACT COVERAGE
AND INTENSITY. LOW CHC POP WED IS REASONABLE AND WILL HOLD ONTO
SLIGHT CHC FOR TUE AND TUE NIGHT BUT HAVE TRENDED DOWN A LITTLE.
SPRAWLING 5H RIDGE WILL BUILD OVER THE CENTRAL AND EASTERN CONUS THU
AND FRI. SURFACE HIGH CENTERED NORTHWEST OF THE AREA WILL ENSURE
NORTH TO NORTHEAST FLOW THU. RIDGE AXIS SHIFTS EAST FRI AND BECOMES
ELONGATED WITH NORTHEAST WINDS VEERING TO EASTERLY LATE IN THE
PERIOD. SUBSIDENCE AND DRY AIR ASSOCIATED WITH 5H RIDGE KEEPS THE
END OF THE FORECAST DRY.
AHEAD OF THE COLD FRONT TEMPERATURES WILL CONTINUE TO RUN ABOVE
CLIMO. COLD ADVECTION BEHIND THE FRONT ON WED DOES NOT LOOK AS
SIGNIFICANT AS IT HAS BEEN WITH MORE RECENT FRONTS. ALTHOUGH HIGHS
AND LOWS FALL BELOW CLIMO FOR THU/FRI NUMBERS WILL ONLY BE A FEW
DEGREES OFF CLIMO.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...MODERATE CONFIDENCE THROUGH THE VALID PERIOD DUE TO
VARYING CLOUDS TODAY...AND FOG THREAT OVERNIGHT.
VISIBLE IMAGERY CONTINUING TO SHOW MID LEVEL CLOUD COVER INLAND WITH
NOTHING AT THE COAST. AMPLE STRATOCU OFFSHORE IS NOT MAKING IT
WESTWARD...BUT STILL EXPECT SOME CU ADVECTING ONSHORE AS WINDS TURN
TO THE SE AND PERSIST THROUGH TONIGHT. INLAND TERMINALS WILL
CONTINUE BKN MID LEVEL CU CIGS THROUGH NIGHTFALL. ATTM...AM
DISCOUNTING THE ENTIRELY OVERAGGRESSIVE NAM WHICH STILL WANTS MVFR
STRATUS ALONG THE COAST...AND WILL KEEP VFR THROUGH TONIGHT. WINDS
WILL BE LIGHT...BECOMING SE AT LESS THAN 10 KTS.
GUIDANCE STILL DEPICTING WIDESPREAD IFR FOG OVERNIGHT...AND WITH
LESS CLOUD COVER NOW EXPECTED BUT SE WINDS RAISING THE TD/S...FOG
NOW APPEARS LIKELY. IF SKY CONDITIONS CLEAR AS DEPICTED ON NON-NAM
FORECAST SOUNDINGS...NEARLY IDEAL RADIATIONAL COOLING WILL EXIST
SINCE WINDS SHOULD FULLY DECOUPLE. THIS COMBINED WITH THE FACT THAT
MINS SHOULD EXCEED THEIR CROSSOVER TEMPS MEANS THAT IFR FOG IS
EXPECTED AT ALL TERMINALS. HAVE INTRODUCED IFR EVERYWHERE...AND WILL
GET MORE SPECIFIC WITH LATER UPDATES SINCE LIFR IS POSSIBLE. VERY
LIGHT WINDS CONTINUING ON SUNDAY WILL ONLY SLOWLY LIFT FOG INTO
STRATUS...ESPECIALLY INLAND...BUT VFR IS EXPECTED BY LATE MORNING.
EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG MONDAY/TUESDAY MORNINGS AND
ISOLATED SHOWERS DURING THE AFTERNOONS. SHOWERS ASSOCIATED WITH A
COLD FRONT MAY IMPACT THE TERMINALS ON WEDNESDAY. VFR THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM SATURDAY...COASTAL TROUGH JUST TO THE EAST OF LOCAL
WATERS KEEPING A SLIGHTLY TIGHTER GRADIENT WITH A NE FLOW OVER
OUTER WATERS UP TO 15 KTS. EXPECT THIS SURFACE TROUGH TO PUSH A
LITTLE FARTHER WEST THROUGH THIS EVENING AND DISSIPATING BY
DAYBREAK...LEAVING WEAK HIGH PRESSURE RIDGING INTO THE CAROLINAS.
THEREFORE EXPECT SFC WINDS TO SHIFT SLIGHTLY MORE EAST BEFORE
BECOMING JUST LIGHT AND VARIABLE OVERNIGHT AROUND 5 TO 10 KTS.
PATCHY CU MAY CONTINUE TO MOVE OVER THE LOCAL WATERS OR DEVELOP
ALONG THE SFC TROUGH. CAN NOT RULE OUT A SPRINKLE AS TROUGH MOVES
SLIGHTLY CLOSER TO THE COAST THIS EVENING BEFORE BREAKING UP.
SLIGHTLY LONGER PERIOD E-NE SWELL COMING AROUND THE HIGH PRESSURE
WILL COMBINE WITH LOCALLY MINIMAL WIND WAVE TO PRODUCE SEAS IN THE
2 TO 3 FT RANGE MOST WATERS. EXPECT OUTER WATERS IN THE 3 TO 4 FT
RANGE WITH SLIGHTLY GREATER WINDS THIS AFTERNOON.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE RIDGE AXIS OVER THE WATERS ON SUN WILL
RESULT IN A LIGHT AND HIGHLY VARIABLE WIND FIELD. THE EXCEPTION WILL
BE ALONG THE COAST WHERE AFTERNOON SEA BREEZE IS LIKELY TO IMPART AN
ONSHORE COMPONENT AND A SEVERAL KT INCREASE IN WIND SPEEDS. RIDGE
AXIS SHIFTS SOUTHEAST OF THE WATERS MON WITH LIGHT SOUTH TO
SOUTHWEST FLOW SETTING UP. SPEEDS WILL BE SLIGHTLY HIGHER THAN ON
SUN...BUT NOT MUCH ABOVE 10 KT. SEAS WILL RUN 2 TO 4 FT THROUGH THE
PERIOD.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTH TO SOUTHWEST FLOW...AHEAD OF ADVANCING
COLD FRONT...TUE AND TUE NIGHT WILL INCREASE IN STRENGTH. INCREASE
IN WINDS WILL ALSO BRING ABOUT AN INCREASE IN SEAS. APPEARS AS
THOUGH THERE MAY BE A PERIOD ON WED WHERE BOTH WINDS AND SEAS FLIRT
WITH SCA THRESHOLDS. ONCE FRONT PASSES OFFSHORE FLOW WILL REMAIN
CLOSE TO SCA THRESHOLDS...POSSIBLY REQUIRING SCA THROUGH THE END OF
THE PERIOD. WEST TO NORTHWEST COMPONENT TO WIND WILL KNOCK SEAS
WITHIN 20 NM BELOW 6 FT PRETTY QUICKLY ON WED BUT SEAS WILL ON THE
CHOPPY SIDE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...JDW
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 AM EST SAT NOV 19 2011
.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST WILL EXTEND
WESTWARD OVER THE REGION THROUGH TUESDAY... BRINGING AN INCREASING
SOUTHERLY FLOW AND A WARMING TREND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 940 AM SATURDAY...
DESPITE THE SURFACE HIGH PRESSURE RIDGE EXTENDING FROM NORTHEAST TO
SOUTHWEST ACROSS CENTRAL NC AND .08 INCHES OF PW AT GSO THIS
MORNING...STRONG SOUTHERLY WARM ADVECTION AT 925MB (9C AT FCC AND 2C
GSO) IS SPREADING STRATUS NORTH OVER THE FOOTHILLS AND INTO THE
WESTERN PIEDMONT. ON ADDITION...WEAK ISENTROPIC LIFT AT 295K...PER
LOCAL HI-RES WRF GUIDANCE... APPEARS TO HAVE HELPED ESTABLISH A
NARROW REGION OF STRATUS ALONG THE I-95 CORRIDOR. THIS STRATUS OVER
THE EAST HAS LESS SUPPORT AND SHOULD LIFT TO SCATTERED STRATOCU THIS
MORNING AND NOT HAVE SIGNIFICANT IMPACT ON TEMPS THIS AFTERNOON. ON
THE OTHER HAND...THE REGIONAL SCALE STRATUS MOVING INTO THE WESTERN
PIEDMONT MAY ACTUALLY HOLD TEMPS DOWN ALONG THE WESTERN FRINGES OF
THE CWA...FROM WADESBORO TO WINSTON-SALEM. 06Z MAV GUIDANCE SEEMS
TO HAVE A BETTER HANDLE ON THIS...AND ADJUSTMENTS TOWARD MAV VALUES
YIELDS 53-61 FROM WEST TO EAST. HAVE ALSO ADJUST CLOUD COVER OVER
THE CENTRAL AND NORTHERN PIEDMONT TO SHOW MORE SUN THIS AFTERNOON
AND A GRADUAL INCREASE THIS EVENING. THIS IS IN LINE WITH
LATEST RUC GUIDANCE FOR KRDU WHICH SHOWS A MORE RAPIDLY INCREASE IN
MOISTURE THIS EVENING AS MOISTURE BECOMES TRAPPED BELOW THE
SUBSIDENCE AND NOCTURNAL INVERSIONS. -SMITH
OVERNIGHT... LOW STRATUS AND/OR FOG WILL KEEP LOWS WARMER THAN
PREVIOUS NIGHTS... GENERALLY IN THE LOW TO MID 40S. -KRR
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 317 AM SATURDAY...
SUNDAY AND SUNDAY NIGHT...WITH SURFACE HIGH PRESSURE EVEN FURTHER
OFFSHORE BY THIS POINT IN THE FORECAST...THE CONTINUED SOUTHERLY
FLOW ACROSS THE REGION WILL RESULT IN HIGH TEMPS REBOUNDING INTO THE
UPPER 60S TO LOWER 70S. MID/HIGH CLOUDS WILL BE ON THE INCREASE LATE
SUNDAY AS A FRONTAL SYSTEM TO OUR NORTH EDGES CLOSER TO THE FORECAST
AREA. WITH THE INCREASED CLOUDS AND MOISTURE...OVERNIGHT LOWS WILL
ONCE AGAIN EXPERIENCE A WARMING TREND...WITH MIN TEMPS ONLY EXPECTED
TO FALL INTO THE LOW 50S AREAWIDE. -KRR
MONDAY-MONDAY NIGHT...A FLAT BROAD UPPER LEVEL RIDGE OVER THE GULF
OF MEXICO AND THE MAIN BAND OF WESTERLIES STRETCHING ACROSS THE
GREAT LAKES INTO NEW ENGLAND WILL RESULT IN A MILD/WARM PERIOD
ACROSS CENTRAL NC. A SURFACE COLD FRONT WILL LIE TO OUR NORTH MONDAY
THEN TRY TO EDGE S-SW INTO CENTRAL NC MONDAY NIGHT AS A CANADIAN
HIGH PRESSURE SYSTEM TRAVERSES ACROSS NEW ENGLAND. MODELS HAVE BEEN
DIFFERING ON THE SOUTHWARD EXTENT OF THIS BOUNDARY WITH THE NAM AND
NOW THE LATEST ECMWF DRAGGING THE BOUNDARY NEAR OR JUST SW OF RDU BY
DAYBREAK TUESDAY WHILE THE GFS KEEPS THE FRONT TO OUR NE (CLOSER TO
RZZ/IXA). CONSIDERING THE STRENGTH OF THE HIGH AND THE LOW LEVEL
COLD AIR ASSOCIATED WITH THIS SYSTEM...MAY BE SOME VALIDITY IN THE
MORE SOUTHERN SCENARIO DEPICTED BY THE NAM/ECMWF. SW LOW LEVEL FLOW
MONDAY AHEAD OF THE FRONT SHOULD MAINTAIN WARM CONDITIONS.
THICKNESSES WITH FULL-PARTIAL SUN SUPPORT MAX TEMPS 10-14 DEGREES
ABOVE NORMAL...YIELDING AFTERNOON TEMPS IN THE 70-75 DEGREE RANGE.
DUE TO PROXIMITY OF THE FRONT AND MARGINAL MOISTURE AVAILABILITY
COUPLED WITH MODEST LIFT...WILL MAINTAIN A SLIGHT CHANCE POP OVER
THE NORTHERN COUNTIES MONDAY...AND A SLIGHT HIGHER POP (THOUGH STILL
SLIGHT CHANCE) OVER THE NORTHERN TWO-THIRDS MONDAY NIGHT. DUE TO
CLOUD COVERAGE...HAVE RAISED MON TEMPS UP A CATEGORY MOST LOCALES
MONDAY NIGHT FROM PREVIOUS FORECAST. MIN TEMPS 53-57. -WSS
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 337 AM SATURDAY...
TUESDAY...AS NEW ENGLAND HIGH SHIFTS OFFSHORE AND THE NEXT S/W AND
ATTENDANT COLD FRONT APPROACH FROM THE WEST...LOW LEVEL FLOW WILL
BECOME MORE SLY ACROSS CENTRAL NC. THIS WILL RETURN THE SURFACE
FRONT NWD AS A WARM FRONT TUESDAY. THE MODEST OVERRUNNING ALONG THIS
BOUNDARY MAY SUPPORT A FEW SHOWERS...MAINLY ACROSS OUR FAR
NORTH-NE COUNTIES. TIMING FAVORS TUESDAY MORNING. TUESDAY AFTERNOON
INTO TUESDAY EVENING SHOULD FEATURE MAINLY DRY AND SEASONABLY WARM
CONDITIONS. WITH LOW LEVEL THICKNESSES BACK INTO THE 1380S....EXPECT
ANOTHER DAY OF WELL ABOVE NORMAL TEMPS WITH HIGHS IN THE 70-75
DEGREE RANGE (WARMEST S-SW AND COOLER FAR NE).
AMPLIFYING S/W CROSSING THE GREAT LAKES AND OH VALLEY TUESDAY NIGHT
WILL ADVANCE AND CROSS CENTRAL NC WEDNESDAY. GFS TIMING IS STILL A
BIT FASTER COMPARED TO THE ECMWF. CONSIDERING THAT THE SYSTEM IS
AMPLIFYING TUESDAY NIGHT INTO WEDNESDAY MORNING...FAVOR SLOWER
TIMING OF THE ECMWF. EFFECTIVE BULK SHEAR INCREASES LATE TUESDAY
NIGHT INTO WEDNESDAY AHEAD OF THE SYSTEM. THUS...SHOULD SEE BROKEN
BANDS OF SHOWERS AHEAD OF THE FRONT. EXPECT SHOWER ACTIVITY TO
INCREASE AFTER MIDNIGHT OVER THE NW PIEDMONT...AND ACROSS THE
REMAINDER OF THE PIEDMONT BY WEDNESDAY MORNING. BY WEDNESDAY
AFTERNOON SURFACE FRONT SHOULD BISECT THE FORECAST AREA...SUGGESTING
BULK OF SHOWERS OCCURRING ALONG AND EAST OF HIGHWAY 1. WHILE BULK
SHEAR SUPPORTIVE OF ORGANIZED CONVECTION...MODELS DEPICT LITTLE IF
ANY LOW LEVEL INSTABILITY AT THIS TIME AND HELICITY MARGINAL AT
BEST. THUS WHILE CANNOT RULE OUT A FEW T-STORMS...MAINLY IN THE EAST
WEDNESDAY AFTERNOON...CURRENT CONVECTIVE PARAMETERS SUGGEST MINIMAL
SEVERE WEATHER THREAT AT THIS TIME. TEMPS WEDNESDAY HIGHLY DEPENDENT
ON SHOWER COVERAGE. POTENTIAL FOR A WIDER MAX TEMP VARIANCE THAN
CURRENTLY FORECAST (WITH WARMER MAX TEMPS POSSIBLE SE).
FRONTAL SYSTEM SHOULD EXIT THE REGION EARLY WEDNESDAY EVENING WITH
IMPROVING WEATHER CONDITIONS. DRY AND SEASONABLY COOL TEMPS EXPECTED
IN THE WAKE OF THE SYSTEM FOR THANKSGIVING DAY AND FRIDAY AS HIGH
PRESSURE BUILDS INTO THEN SETTLES OVER THE REGION.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 630 AM SATURDAY...
CURRENT SATELLITE IMAGERY AND OBSERVATIONS INDICATE THAT A NARROW
BAND OF STRATUS HAS DEVELOPED ACROSS THE COASTAL PLAIN...WITH SOME
SITES BRIEFLY EXPERIENCING MVFR CIGS. ONCE THE SUN COMES UP AND SOME
MIXING BEGINS...AM EXPECTING THE CLOUDS TO SCATTER OUT BRIEFLY. AS A
SURFACE HIGH PRESSURE CONTINUES TO SHIFT OFFSHORE TODAY...A
WARM/MOIST SOUTHERLY RETURN FLOW WILL INCREASE ACROSS THE REGION (AN
AREA OF CLOUDINESS ASSOCIATED WITH THIS RETURN FLOW CAN ALREADY BE
SEEN ACROSS GEORGIA AND SOUTH CAROLINA). THIS SOUTHERLY RETURN
FLOW/WARM ADVECTION THAT WILL RESULT IN THE POTENTIAL DEVELOPMENT OF
MVFR CEILINGS LATER THIS MORNING OR THIS AFTERNOON. CONFIDENCE IS
STILL NOT VERY HIGH WITH RESPECT TO WHETHER OR NOT THE CLOUDS WILL
BE BROKEN OR SCATTERED...BUT OVERALL...CLOUDS WILL BE ON THE
INCREASE THROUGH THE DAY. THEN...IFR/LIFR CIGS/VSBYS ARE EXPECTED TO
DEVELOP OVERNIGHT IN ASSOCIATION WITH THE CONTINUED SOUTHERLY RETURN
FLOW AND WARM ADVECTION.
OUTLOOK...CEILINGS SHOULD IMPROVE TO MVFR AND EVENTUALLY VFR BETWEEN
12-18Z SUN IN ASSOC/W DIURNAL HEATING AND MIXING. IFR/LIFR
CONDITIONS WILL BE POSSIBLE AGAIN BETWEEN 00-12Z MON...ALTHOUGH
THERE IS LESS CERTAINTY THAN THE 00-12Z SUN PERIOD. UNCERTAINTY
INCREASES BY EARLY/MID NEXT WEEK. AT THIS TIME...EXPECT MVFR
CEILINGS WITH PERIODS OF IFR CEILINGS (PRIMARILY OVERNIGHT) TO
PREDOMINATE MON/TUE AHEAD OF A STORM SYSTEM EXPECTED TO DEVELOP IN
THE CENTRAL PLAINS AND LOWER MS RIVER VALLEY. THE AFOREMENTIONED
STORM SYSTEM IS EXPECTED TO AFFECT THE CAROLINAS LATE TUE
NIGHT/WED...BRINGING WITH IT A CHANCE FOR SHOWERS/STORMS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...KRR/SMITH
SHORT TERM...KRR/WSS
LONG TERM...WSS
AVIATION...KRR/VINCENT
AREA FORECAST DISCUSSION
NWS NORMAN OK
1144 AM CST SAT NOV 19 2011
.UPDATE...
COLD FRONT ACROSS KANSAS IS MOVING INTO NORTHWEST OKLAHOMA RIGHT
NOW WITH BUFFALO AND MAY RANCH MESONET STATIONS HAVING TURNED TO
NORTH WINDS ALREADY. THE FRONT IS A BIT AHEAD OF SCHEDULE AND HAVE
MADE ADJUSTMENTS IN THE FORECAST FOR THIS. OVERALL... THE CURRENT
RUC SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION AND LOOKED LIKE A
GOOD SOURCE TO REPOPULATE THE WIND... DEWPOINT AND TEMPERATURE
GRIDS. HAVE ALSO MADE ADJUSTMENTS TO CLOUD COVER BASED ON CURRENT
TRENDS. THE RUC AND THE LOCAL WRF MODELS SUGGEST THE POSSIBILITY
OF CONVECTION DEVELOPING ALONG THE FRONT IN NORTHEAST OKLAHOMA AND
DEVELOPING TOWARD THE NORTHEAST PORTION OF THE CWA BUT NEITHER
MODEL DEVELOPS CONVECTION IN THE CWA. WILL NOT ADD POPS TO THE
AFTERNOON PERIOD WITH THIS UPDATE BUT WILL CONTINUE TO WATCH
TRENDS BOTH HERE AND ACROSS THE FAR SOUTHEAST PORTION OF THE AREA.
&&
.PREV DISCUSSION... /ISSUED 545 AM CST SAT NOV 19 2011/
AVIATION...
MVFR CONDITIONS WILL PREVAIL THIS MORNING OVER EASTERN SITES WITH
VFR IN THE WEST. FRONT WILL MOVE THROUGH THE REGION OVERNIGHT WITH
MVFR AND POSSIBLY SOME IFR CONDITIONS DEVELOPING BEHIND THE FRONT.
PREV DISCUSSION... ISSUED 425 AM CST SAT NOV 19 2011/
DISCUSSION...
LOW CLOUDS HAVE SPREAD OVER MUCH OF THE EASTERN HALF OF THE FA THIS
MORNING AS LOW LEVEL MOISTURE CONTINUES TO INCREASE WITH PERSISTENT
SOUTHERLY FLOW. COLD FRONT APCHG NWRN KS EARLY THIS MORNING IS
EXPECTED TO SURGE SOUTHWARD TODAY AS S/W TROUGH MOVES THROUGH THE
NRN PLAINS. FRONT WILL LIKELY MOVE INTO FAR NRN PARTS OF OK THIS
AFTERNOON. THE FRONT WILL CONTINUE SOUTHWARD TONIGHT EDGING INTO
SRN PARTS OF THE FORECAST AREA BY EARLY SUNDAY MORNING...BEFORE
STALLING OUT NEAR OR JUST SOUTH OF THE RED RIVER BY SUNDAY
NIGHT/MONDAY MORNING. MOISTURE WILL CONTINUE TO INCREASE AHEAD OF
THE FRONT AND SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...MAINLY SOUTHEAST TONIGHT. SHOWERS AND THUNDERSTORMS
CHANCES WILL CONTINUE SUNDAY...MAINLY NEAR AND NORTH OF THE FRONT
AIDED BY ISENTROPIC LIFT AND MINOR IMPULSES MOVING THROUGH THE
SWLY FLOW ALOFT. MORE WIDESPREAD RAIN AND THUNDERSTORMS EXPECTED
MONDAY/MONDAY NIGHT AS LIFT INCREASES WITH THE APPROACH OF THE
SWRN U.S. UPPER TROUGH. HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY IN SOUTHERN AREAS NEAR AND JUST NORTH OF THE
STALLED FRONT. MODELS REMAIN IN FAIRLY GOOD AGREEMENT WITH THE
TIMING OF THE EXITING UPPER SYSTEM WITH THE PRECIP EXPECTED TO
COME TO AN END ON TUESDAY. DRY WEATHER IS THEN EXPECTED THROUGH
MID WEEK WITH RAIN CHANCES RETURNING LATE IN THE WEEK WITH THE
APPROACH OF ANOTHER UPPER TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 72 44 49 41 / 10 10 10 20
HOBART OK 73 39 51 42 / 0 0 0 10
WICHITA FALLS TX 77 54 61 50 / 10 10 10 30
GAGE OK 73 29 47 34 / 0 0 0 0
PONCA CITY OK 71 34 44 33 / 10 10 10 10
DURANT OK 76 65 77 55 / 10 30 30 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
850 PM CST SUN NOV 20 2011
.DISCUSSION...
TOUGH UPDATE TONIGHT WITH WARM AIR ADVECTION AND CLOUD COVER
INCREASING ACROSS THE AREA OVERNIGHT. TEMPERATURES HAVE NOT FALLEN
MUCH THROUGH THE EVENING HOURS...AND HAVE BEGUN TO CREEP UPWARDS IN
A FEW LOCATIONS. HAVE LEFT SOME BREATHING ROOM ON THE BOTTOM END
FOR LOWS TONIGHT IN CASE LOCATIONS ARE ABLE TO DECOUPLE OVER THE
NEXT FEW HOURS...BUT IF THIS DOESN/T OCCUR EXPECT TO SEE A GENERAL
UPWARD TREND IN TEMPERATURES. BEST CHANCE OF DECOUPLING WILL BE IN
THE FAR EAST WHERE THE UPPER RIDGE WILL HANG ON FOR A FEW MORE
HOURS. SPEAKING OF THE EAST...STRATUS ALONG I-90 HAS SURGED BACK TO
JUST TO THE WEST OF ALBERT LEA MN AS OF 2Z. RUC SUGGESTS THIS IS
GOING TO CONTINUE TO BACK TO THE WEST THROUGHOUT THE NIGHT.
CEILINGS WITHIN STRATUS ARE FAIRLY LOW AND AM CONCERNED ABOUT FOG
POTENTIAL...BUT AFTER COLLABORATING WITH NEIGHBORING OFFICES TO THE
EAST OPTED TO LEAVE MENTION OUT OF THE FORECAST FOR NOW. INCREASED
SKY COVER IN FAR EAST..BUT THINK THE STRATUS WILL FIGHT WARM AIR
ADVECTION AND DRY AIR TO THE WEST AND WILL STRUGGLE ADVANCING MUCH
FURTHER WEST THAN FAR EASTERN TIER OF COUNTIES. UPDATE POSTED.
&&
.AVIATION.../FOR THE 00Z TAFS/
VFR CONDITIONS EXPECTED THROUGH 00Z TUESDAY WITH OCCASIONAL CEILINGS
NEAR BKN120.
&&
.DISCUSSION.../ISSUED AT 307 PM CST/
MAIN FORECAST PROBLEM TONIGHT WILL BE LOW TEMPERATURES WHICH WILL
LIKELY OCCUR BEFORE MIDNIGHT BEFORE WARM AIR ADVECTION KICKS IN
ALONG WITH SOME INCREASE IN MID AND HIGH CLOUDS. WITH TEMPERATURES
IN TEENS AND 20S MOST PLACES THIS AFTERNOON...WILL NOT HAVE FAR TO
FALL WITH LIGHT WINDS...SO WILL GO LOWER THAN GUIDANCE...ESPECIALLY
SNOW COVERED AREAS...WITH STEADY OR SLOWLY RISING TEMPERATURES AFTER
MIDNIGHT AS LOW LEVEL SOUTHEASTERLY WINDS INCREASE.
A TREND OF SLOW WARMING WILL CONTINUE THROUGH LATE AFTERNOON ON
MONDAY...BUT WITH DECREASING WINDS IN THE EVENING...TEMPERATURES
WILL LIKELY DROP OFF QUICKLY BEFORE MIDNIGHT. HOWEVER...THE WARMER
AND MORE MOIST AIRMASS THAT WILL ADVECT INTO THE REGION ON MONDAY
SHOULD PREVENT OVERNIGHT LOWS FROM BOTTOMING OUT MUCH BELOW AVERAGE.
FOR THE REMAINDER OF THE WORK WEEK...TEMPERATURES WILL GENERALLY BE
ABOVE AVERAGE AS ZONAL FLOW BUILDS INTO A LONGWAVE RIDGE ACROSS THE
CENTRAL PLAINS. A SPLIT DISTURBANCE WILL MOVE THROUGH THE REGION ON
TUESDAY...BUT SHOULD NOT IMPACT THE FORECAST AREA EXCEPT FOR A
SLIGHT INCREASE IN CLOUD COVER ACROSS THE SOUTHEASTERN CORNER OF THE
CWA.
ON FRIDAY...A DEEP TROUGH WILL MOVE THROUGH THE REGION...BRINGING A
SURFACE COLD FRONT ACROSS THE PLAINS BY FRIDAY EVENING. CURRENTLY
PRECIPITATION CHANCES LOOK LOW...ESPECIALLY ACROSS THE WESTERN HALF
OF THE REGION WHERE FRONTAL PASSAGE WILL OCCUR EARLIER IN THE DAY
AND THE TEMPERATURE GRADIENT WILL NOT BE QUITE AS IMPRESSIVE.
MOISTURE WILL ALSO BE QUITE LIMITED EVEN AS THE FRONT MOVES THROUGH
NW IA AND SW MN...SO LEFT THE CHANCE OF PRECIPITATION FAIRLY LOW
THROUGHOUT THE EVENT. AFTER THE SYSTEM EXITS THE AREA ON SATURDAY
MORNING...TEMPERATURES WILL BRIEFLY RETURN TO NORMAL VALUES...WITH
NO ADDITIONAL PRECIPITATION EXPECTED THROUGH THE FORECAST PERIOD.
/LAFLIN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
702 PM CST SUN NOV 20 2011
.UPDATE...
THE IMMEDIATE THREAT FOR SEVERE WEATHER IN NORTH TEXAS APPEARS TO
BE WANING AND THUS HAVE CANCELLED THE WATCH FOR ALL OF NORTH
TEXAS. EXPECT THAT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE THROUGH THE NIGHT AND SOME OF THESE MAY PRODUCE
SMALL HAIL AND NUMEROUS CLOUD TO GROUND LIGHTNING STRIKES. THE 00Z
FWD SOUNDING SHOWS THE COLD FRONT TO BE CONFINED BELOW 925 MB OR
BELOW 3000 FT. ABOVE THE COLD FRONT THE ATMOSPHERE IS UNCAPPED AND
UNSTABLE BUT WEAK LAPSE RATES AND A LACK OF SIGNIFICANT
/UPWARD FORCING BEHIND THE FRONT IS LIKELY KEEPING THE SHOWERS
AND THUNDERSTORMS BELOW SEVERE LIMITS.
THE COLD FRONT IS MAKING AN IMPRESSIVE ADVANCEMENT SOUTH AND HAS
NOW PASSED THROUGH LAMPASAS AND PARTS OF NORTHERN BELL COUNTY. THE
WESTERN PORTION OF THE FRONT HAS MORE PUSH THAN THE EASTERN
SECTION AS THE FRONT THEN DRAPES TO THE NORTHEAST TOWARDS
CORSICANA AND EMORY. THE TEMPERATURE FORECAST FOR TONIGHT HAS BEEN
ADJUSTED BASED ON THIS LATEST POSITION BUT MAY NEED TO BE ADJUSTED
AGAIN DEPENDING ON HOW FAR SOUTH THE EASTERN PORTION ADVANCES.
WITH THE FRONT FARTHER SOUTH THAN PREVIOUS FORECAST...THIS COULD
AFFECT THE CONVECTIVE FORECAST FOR TOMORROW BUT WILL NOT BE MAKING
CHANGES AT THIS TIME.
82/JLD
&&
.AVIATION...
MULTIPLE AVIATION WEATHER CONCERNS THROUGH MONDAY AFTERNOON WITH
MVFR CEILINGS/VISIBILITIES EXPECTED THROUGH THE EVENING...BECOMING
IFR AFTER SUNRISE MONDAY AND REMAINING IFR UNTIL MID AFTERNOON.
A COLD FRONT...CURRENTLY NEAR A LAMPASAS...WACO...CORSICANA...TO
EMORY LINE...WILL REMAIN NEARLY STATIONARY OVERNIGHT AND LIFT
NORTHWARD ON MONDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE POSSIBLE NEAR AND NORTH OF THE COLD FRONT OVERNIGHT WITH
STORM CHANCES INCREASING ON MONDAY AS THE FRONT LIFTS NORTH AND
LARGE SCALE LIFT INCREASES. THE BEST THUNDERSTORM CHANCES AT ALL
TAF SITES WILL BE MONDAY AFTERNOON/MONDAY NIGHT.
A NORTH/NORTHWEST WIND WILL PREVAIL AT ALL TAF SITES OVERNIGHT AT
SPEEDS BETWEEN 6 AND 12 KNOTS ALONG WITH SOME HIGHER GUSTS THIS
EVENING. THE WIND WILL SLOWLY TURN TO THE NORTHEAST/EAST ON MONDAY
AS THE FRONT BEGINS TO LIFT NORTHWARD AND EVENTUALLY BECOME
SOUTHEAST MONDAY AFTERNOON/EVENING.
79
&&
.PREV UPDATE...
.UPDATE...
SEVERE THUNDERSTORM WATCH #893 UNTIL 05Z/11PM THIS EVENING FOR
AREAS FROM GRANBURY AND MARLIN...NORTHEAST TO BONHAM...PARIS AND
PALESTINE. UPDATES FORTH COMING. 75
&&
.PREV DISCUSSION... /ISSUED 157 PM CST SUN NOV 20 2011/
...SEVERE THUNDERSTORM POTENTIAL CONTINUES ACROSS PORTIONS OF NORTH
TEXAS LATER THIS AFTERNOON AND AGAIN ON MONDAY AFTERNOON AND
EVENING...
OVERALL...THIS AFTERNOONS FORECAST PACKAGE CONTINUES THE TRENDS
MENTIONED IN PREVIOUS FORECASTS OVER THE PAST SEVERAL DAYS. THE
COLD FRONT IS RUNNING SLIGHTLY AHEAD OF PREVIOUS TIMING...BUT
FAIRLY CLOSE TO THE NAM AND RUC MODEL SOLUTIONS. AT 145 PM IT
EXTENDS FROM PARIS TO CLEBURNE TO SOUTH OF COMANCHE.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON THROUGH MID/LATE EVENING AS FORCING FOR ASCENT ARRIVES
FROM THE WEST AND HELPS WEAKEN THE STRONG CAP AROUND 860MB. VERY
MOIST AND UNSTABLE AIR AHEAD OF THE COLD FRONT WILL PRODUCE CAPES
500-1200 J/KG THIS EVENING AND 700-1400 J/KG ON MONDAY. BULK SHEAR
0-6KM WILL BE IN THE RANGE OF 40-60 KTS BOTH DAYS ALONG WITH
HELICITY VALUES GREAT THAN 200 M2/S2. AS PREVIOUSLY STATED...LARGE
HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM THREAT FOLLOWED BY
DAMAGING WINDS AND BRIEF ISOLATED TORNADOES. AREAS TO WATCH FOR
QUICK TORNADOGENESIS ARE...WHERE SURFACE WINDS ARE BACKED AND
THOSE CELLS THAT MOVE NEAR AND ALONG THE COLD FRONT. HAVE ADDED
SEVERE WORDING TO THE ZONE PACKAGE IN THIS RELEASE.
THE SYSTEM SHOULD MOVE OUT OF NORTH TEXAS LATE TUESDAY AFTERNOON
WITH FAIR WEATHER FOR WEDNESDAY AND THANKSGIVING DAY. OUR NEXT
SYSTEM WILL ARRIVE FRIDAY WITH ANOTHER ROUND OF THUNDERSTORMS AND
BENEFICIAL RAINFALL FOR NORTH TEXAS. THIS SYSTEM WILL MOVE RIGHT
ON THROUGH THE REGION AND SHOULD BE OUT OF NORTH TEXAS LATE FRIDAY
NIGHT. AFTERWARD...IT WILL BE DRY WITH SEASONAL TEMPERATURES OVER
THE WEEKEND. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 73 60 69 45 / 60 80 90 40 10
WACO, TX 58 79 63 75 44 / 60 50 80 50 10
PARIS, TX 50 72 62 68 44 / 60 80 90 60 10
DENTON, TX 42 69 55 66 41 / 60 80 90 20 5
MCKINNEY, TX 45 71 59 67 43 / 60 80 90 50 10
DALLAS, TX 45 75 61 70 47 / 60 80 90 50 10
TERRELL, TX 55 76 65 70 45 / 60 60 90 50 10
CORSICANA, TX 62 79 66 75 47 / 60 40 80 70 10
TEMPLE, TX 66 79 65 77 46 / 60 30 70 60 10
MINERAL WELLS, TX 42 72 53 68 40 / 30 80 90 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
THE 00Z AVIATION FORECAST DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
A CHALLENGING AVIATION FORECAST THROUGH MONDAY AFTERNOON...WITH
CONCERNS FOR DEVELOPING LOW CEILINGS...POTENTIAL VISIBILITY
RESTRICTIONS DUE TO FOG AND DRIZZLE...AND THEN LATER ISOLATED TO
SCATTERED SHRA/TSRA.
SATELLITE IMAGERY AND AREA SURFACE OBSERVATIONS SHOW A COLD FRONT
EXTENDING FROM JUST WEST OF KCNM...TO NEAR KPEQ...TO NEAR
KFST...THEN EASTWARD TO JUST SOUTH OF KSJT AS OF 21/00Z. MVFR TO
IFR CEILINGS ARE CURRENTLY SITUATED ALONG AND EAST OF A
KSNK...KBPG LINE. THE LATEST NAM BUFR AND RUC FORECAST SOUNDINGS
ARE IN GENERAL AGREEMENT THAT LOW CEILINGS WILL GRADUALLY DEVELOP
AND SPREAD WESTWARD ACROSS THE PERMIAN BASIN THIS EVENING...THEN
WESTWARD ACROSS THE SOUTHEAST NEW MEXICO PLAINS AND THE TRANS
PECOS REGION AROUND OR JUST AFTER MIDNIGHT. FORECAST SOUNDINGS
ARE IN FAIRLY GOOD AGREEMENT THAT CEILINGS WILL FALL TO IFR
CATEGORY ACROSS MOST OF THE LOCAL TERMINALS EARLY MONDAY MORNING.
THERE WILL ALSO BE AN OPPORTUNITY FOR MVFR VISIBILITY RESTRICTIONS
DUE TO FOG/LIGHT DRIZZLE AFTER MIDNIGHT AND TOWARD SUNRISE...
MAINLY AROUND KHOB AND KMAF.
AN APPROACHING UPPER LEVEL TROUGH MAY INTERACT WITH ELEVATED
INSTABILITY ALONG AND NORTH OF THE SURFACE BOUNDARY TO PRODUCE
ISOLATED TO SCATTERED SHRA/TSRA MONDAY MORNING INTO MONDAY
AFTERNOON. LOCATIONS MAINLY ALONG AND EAST OF A KHOB...KINK LINE
CURRENTLY APPEAR MOST PRONE FOR CONVECTIVE DEVELOPMENT. THE
TIMING AND DURATION OF SHRA/TSRA IS STILL UNCERTAIN...BUT WE WILL
CONTINUE A PROB30 GROUP FOR TSRA AT KMAF MAINLY DURING THE MORNING
HOURS...WITH CB MENTION KEPT IN AT KINK AND KHOB. VFR IS EXPECTED
TO RETURN TO ALL TAF SITES MONDAY AFTERNOON...WITH INCREASING
SOUTHWEST TO WEST WINDS BEHIND AN ADVANCING PACIFIC COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 253 PM CST SUN NOV 20 2011/
DISCUSSION...
AFTERNOON OBSERVATIONS SHOW A COLD FRONT VERY NEAR THE PECOS RIVER
VALLEY...EXTENDING SLIGHTLY BACK TO THE EAST JUST SOUTH OF SAN
ANGELO. THIS FRONT...AND PERSISTENT CLOUD COVER...HAVE KEPT TEMPS
IN THE LOW 50 TO LOW 60 RANGE ACROSS PORTIONS OF SE NM...THE
PERMIAN BASIN...AND WESTERN LOW ROLLING PLAINS. MEANWHILE...A
POTENT VORT MAX IS MOVING ONSHORE NEAR NORTH CENTRAL CALI.
LATE TONIGHT...THIS FEATURE WILL TRAVERSE SOUTHERN CALI AND AN
ASSOCIATED UPPER JET MAX WILL NOSE INTO SOUTH CENTRAL NM. EXPECT A
MODEST NOCTURNAL LLJ TO DEVELOP ACROSS EASTERN PORTIONS OF THE
PERMIAN BASIN AND LOWER TRANS PECOS. THE NAM12 IS A LITTLE MORE
AGGRESSIVE WITH THE STRENGTH OF THE LLJ...WITH SPEEDS AROUND 40 TO
45KT FOR SOME LOCATIONS. REGARDLESS...ALL SOLUTIONS INDICATE
MODERATE TO STRONG ISENTROPIC ASCENT AROUND 12Z TOMORROW MORNING
FROM THE PERMIAN BASIN JUST NORTHWARD. NEAR THE SAME TIME...THE
FIRST SHORTWAVE TROUGH ASSOCIATED WITH THE APPROACHING UPPER
TROUGH FROM THE WEST WILL MOVE INTO SE NM. ALTHOUGH SIGNIFICANT
AMOUNTS OF RAINFALL DO NOT APPEAR LIKELY EARLY TOMORROW
MORNING...THESE TWO LIFTING MECHANISMS...COMBINED WITH SUFFICIENT
LOW LEVEL MOISTURE...WILL AT LEAST SUPPORT STRATIFORM TYPE PRECIP
TOMORROW MORNING ACROSS THE PERMIAN BASIN AND PERHAPS LEA COUNTY.
BEFORE THE PREVIOUSLY MENTIONED LIFT IMPACTS THE AREA...EXPECT
DRIZZLE AND FOG LATE TONIGHT WITH DEWPOINTS ALREADY IN THE UPPER
50S ACROSS THE SE PERMIAN BASIN. AFTER 18Z TOMORROW...THE MAIN
VORT MAX WILL LIKELY TRAVERSE SE NM AND THEN MOVE OVER LUB/S CWA
BY 00Z. UNFORTUNATELY...RAIN CHANCES APPEAR THEY WILL QUICKLY COME
TO AN END FOR MOST LOCATIONS ACROSS OUR CWA CONSIDERING THE
AFOREMENTIONED AND THE EASTWARD PROGRESSION OF THE PAC FRONT
THROUGH THE LATE AFTERNOON AFTERNOON HOURS. HOWEVER...STRONG SFC
CONVERGENCE ALONG THIS FEATURE NEAR THE LOWER TRANS PECOS AND
EXTREME EASTERN PERMIAN BASIN LATE TOMORROW AFTERNOON COMBINED
WITH PLENTY OF DEEP LAYER SHEAR COULD BRIEFLY SUPPORT AN ISOLATED
SEVERE STORM. THE PROBABILITY OF THIS IS LOW THOUGH...SINCE THE
CAPE/LOW CIN WINDOW WILL BE VERY SMALL AND THE ANY STORMS WOULD
QUICKLY MOVE INTO SJT/S CWA. THE TEMPERATURE FORECAST FOR TOMORROW
AND TONIGHT IS A BIT TRICKY...WHICH WILL DEPEND GREATLY ON THE
POSITION OF THE COLD FRONT AND THE EXTENSIVENESS/DURATION OF THE
PRECIP TOMORROW. FOR NOW...WE HAVE DECREASED TEMPS SEVERAL
DEGREES FOR MONDAY AFTERNOON ACROSS THE NORTHERN PB/WESTERN LOW
ROLLING PLAINS WHERE HIGHEST POPS AND COLDER AIRMASS ARE EXPECTED
TO BE.
CLEARING SKIES ARE STILL ANTICIPATED LATE TOMORROW AFTERNOON THROUGH
LATE MONDAY NIGHT...FROM WEST TO EAST...AS THE UPPER TROUGH MOVES
ACROSS THE PANHANDLE EARLY TUESDAY MORNING. A SFC RIDGE WILL BEGIN
TO NUDGE INTO THE REGION FROM THE ROCKIES DURING THE DAY TUESDAY
AS WELL. TEMPS WILL BE NEAR OR JUST BELOW CLIMATOLOGY TUESDAY.
THEN...BY WEDNESDAY MORNING...THE SURFACE RIDGE HIGH IS EXPECTED
TO MOVE DIRECTLY OVERHEAD. THIS SHOULD DROP LOWS BACK INTO THE 30S
FOR MOST LOCATIONS...OR LOWER DEPENDING ON DEWPOINTS. MID TO UPPER
RIDGING WILL PASS OVER THE REGION WED AFTERNOON...AS ANOTHER UPPER
TROUGH APPROACHES THE WESTERN SEABOARD. THIS FEATURE WILL HAVE AN
IMPACT ON OUR WEATHER SOMETIME DURING THE LATE WEEK/WEEKEND
PERIOD...WHICH WILL INCREASE WINDS...DECREASE DEWPOINTS...AND
RESULT IN PERHAPS ANOTHER COLD FROPA.
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
543 PM CST SUN NOV 20 2011
.AVIATION...
MULTIPLE AVIATION WEATHER CONCERNS THROUGH MONDAY AFTERNOON WITH
MVFR CEILINGS/VISIBILITIES EXPECTED THROUGH THE EVENING...BECOMING
IFR AFTER SUNRISE MONDAY AND REMAINING IFR UNTIL MID AFTERNOON.
A COLD FRONT...CURRENTLY NEAR A LAMPASAS...WACO...CORSICANA...TO
EMORY LINE...WILL REMAIN NEARLY STATIONARY OVERNIGHT AND LIFT
NORTHWARD ON MONDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE POSSIBLE NEAR AND NORTH OF THE COLD FRONT OVERNIGHT WITH
STORM CHANCES INCREASING ON MONDAY AS THE FRONT LIFTS NORTH AND
LARGE SCALE LIFT INCREASES. THE BEST THUNDERSTORM CHANCES AT ALL
TAF SITES WILL BE MONDAY AFTERNOON/MONDAY NIGHT.
A NORTH/NORTHWEST WIND WILL PREVAIL AT ALL TAF SITES OVERNIGHT AT
SPEEDS BETWEEN 6 AND 12 KNOTS ALONG WITH SOME HIGHER GUSTS THIS
EVENING. THE WIND WILL SLOWLY TURN TO THE NORTHEAST/EAST ON MONDAY
AS THE FRONT BEGINS TO LIFT NORTHWARD AND EVENTUALLY BECOME
SOUTHEAST MONDAY AFTERNOON/EVENING.
79
&&
.UPDATE...
SEVERE THUNDERSTORM WATCH #893 UNTIL 05Z/11PM THIS EVENING FOR
AREAS FROM GRANBURY AND MARLIN...NORTHEAST TO BONHAM...PARIS AND
PALESTINE. UPDATES FORTH COMING. 75
&&
.PREV DISCUSSION... /ISSUED 157 PM CST SUN NOV 20 2011/
...SEVERE THUNDERSTORM POTENTIAL CONTINUES ACROSS PORTIONS OF NORTH
TEXAS LATER THIS AFTERNOON AND AGAIN ON MONDAY AFTERNOON AND
EVENING...
OVERALL...THIS AFTERNOONS FORECAST PACKAGE CONTINUES THE TRENDS
MENTIONED IN PREVIOUS FORECASTS OVER THE PAST SEVERAL DAYS. THE
COLD FRONT IS RUNNING SLIGHTLY AHEAD OF PREVIOUS TIMING...BUT
FAIRLY CLOSE TO THE NAM AND RUC MODEL SOLUTIONS. AT 145 PM IT
EXTENDS FROM PARIS TO CLEBURNE TO SOUTH OF COMANCHE.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON THROUGH MID/LATE EVENING AS FORCING FOR ASCENT ARRIVES
FROM THE WEST AND HELPS WEAKEN THE STRONG CAP AROUND 860MB. VERY
MOIST AND UNSTABLE AIR AHEAD OF THE COLD FRONT WILL PRODUCE CAPES
500-1200 J/KG THIS EVENING AND 700-1400 J/KG ON MONDAY. BULK SHEAR
0-6KM WILL BE IN THE RANGE OF 40-60 KTS BOTH DAYS ALONG WITH
HELICITY VALUES GREAT THAN 200 M2/S2. AS PREVIOUSLY STATED...LARGE
HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM THREAT FOLLOWED BY
DAMAGING WINDS AND BRIEF ISOLATED TORNADOES. AREAS TO WATCH FOR
QUICK TORNADOGENESIS ARE...WHERE SURFACE WINDS ARE BACKED AND
THOSE CELLS THAT MOVE NEAR AND ALONG THE COLD FRONT. HAVE ADDED
SEVERE WORDING TO THE ZONE PACKAGE IN THIS RELEASE.
THE SYSTEM SHOULD MOVE OUT OF NORTH TEXAS LATE TUESDAY AFTERNOON
WITH FAIR WEATHER FOR WEDNESDAY AND THANKSGIVING DAY. OUR NEXT
SYSTEM WILL ARRIVE FRIDAY WITH ANOTHER ROUND OF THUNDERSTORMS AND
BENEFICIAL RAINFALL FOR NORTH TEXAS. THIS SYSTEM WILL MOVE RIGHT
ON THROUGH THE REGION AND SHOULD BE OUT OF NORTH TEXAS LATE FRIDAY
NIGHT. AFTERWARD...IT WILL BE DRY WITH SEASONAL TEMPERATURES OVER
THE WEEKEND. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 73 60 69 45 / 50 80 90 40 10
WACO, TX 60 79 63 75 44 / 60 50 80 50 10
PARIS, TX 50 72 62 68 44 / 60 80 90 60 10
DENTON, TX 42 69 55 66 41 / 50 80 90 20 5
MCKINNEY, TX 45 71 59 67 43 / 50 80 90 50 10
DALLAS, TX 45 75 61 70 47 / 50 80 90 50 10
TERRELL, TX 55 76 65 70 45 / 60 60 90 50 10
CORSICANA, TX 62 79 66 75 47 / 60 40 80 70 10
TEMPLE, TX 66 79 65 77 46 / 60 30 70 60 10
MINERAL WELLS, TX 42 72 53 68 40 / 40 80 90 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
541 PM CST SUN NOV 20 2011
.AVIATION...
DIFFICULT FORECAST FOR THE TAF SITES FOR THE NEXT 24 TO 36 HOURS.
MVFR CEILINGS ARE EXPECTED TO DEVELOP AT BOTH TAF SITES SOMETIME
TONIGHT BUT THE EXACT TIME REMAINS HIGHLY UNCERTAIN. NEXT ISSUE IS
THE POSSIBILITY OF DRIZZLE AND/OR FOG DEVELOPMENT AT BOTH TAF SITES
WHICH WILL ALSO HELP TO BRING VISIBILITIES DOWN. OVERALL...IT
APPEARS THAT VFR-MVFR CONDITIONS WILL HOLD THROUGH MIDNIGHT LOCAL
TIME AND THEN GRADUALLY START TO DECREASE DOWN INTO IFR RANGE BY
SUNRISE AT BOTH SITES. IFR/MVFR CONDITIONS THEN EXPECTED TO
PERSIST INTO TOMORROW AS RAIN CHANCES INCREASE WITH THE APPROACH
OF A STORM SYSTEM FROM THE WEST. CONFIDENCE IN TIMING FOR ONSET OF
PRECIPITATION IS ALSO VERY LOW BUT EXPECT PRECIP CHANCES TO
PERSIST THROUGH MONDAY AFTERNOON. MAY SEE SOME BRIEF IMPROVEMENT
INTO SOLID MVFR RANGE LATE IN THE DAY MONDAY. EXPECT AMENDMENTS AS
CONDITIONS START TO EVOLVE THROUGH TONIGHT AND AS NEW WEATHER
INFORMATION ARRIVES.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 247 PM CST SUN NOV 20 2011/
SHORT TERM...
MAIN FOCUS FOR THE SHORT TERM PERIOD IS THE IMPENDING WEST COAST
SYSTEM THAT WILL BRING CHANCES OF RAIN COMMENCING TOMORROW...AND
TAMPERING OFF TUESDAY MORNING.
THE PACIFIC UA LOW SYSTEM OF INTEREST WAS LOCATED OFF THE COAST OF
CENTRAL CALIFORNIA PER 20Z WATER VAPOR IMAGERY...AND PROGGED TO OPEN
UP AND EJECT QUICKLY ESE TO ACROSS THE DESERT SOUTHWEST MONDAY
MORNING...ACROSS THE SOUTH PLAINS MONDAY NIGHT AND EAST OF THE
REGION TUESDAY MORNING. THIS RELATIVELY QUICK TRAJECTORY IS BEING
HANDLED WELL BY THE NAM...GFS AND ECMWF SOLUTIONS...WITH PERHAPS THE
NAM BEING A TOUCH FASTER THAN THE LATTER MODELS. 20Z SFC ANALYSIS
DISPLAYED A COLD FRONT THAT SURGED SOUTH ACROSS THE CWA EARLIER THIS
MORNING...AND WAS SPATIALLY DISTRIBUTED FROM A NEAR PINE SPRINGS TO
FORT STOCKTON TO BRADY LINE. THUS LEAVING TEMPS IN THE 40S AND 50S
AND DEWPOINTS IN THE 20S AND 30S IN ITS WAKE. THIS PLACEMENT OF THE
SAID FRONT IS FARTHER SOUTH THAN WHAT MODELS PREDICTED 24 HOURS AGO.
THE GFS AND ECMWF ARE ONLY SLIGHTLY SIMILAR TO THE NAM IN REGARD TO
THE FRONT NOT BEING QUITE AS FAR SOUTH...HENCE THE CURRENT PLACEMENT
OF THE FRONT IS NOT HANDLED WELL BY EITHER AFOREMENTIONED SOLUTION
PER SE. HENCE...THE NAM AND RUC MODELS DISPLAY THE FRONT TRANSLATING
A BIT FARTHER SOUTH TONIGHT /THE RUC IS MOST AGGRESSIVE WITH THIS
POSSIBILITY/ BUT THE NAM AND TO A LESSER EXTENT THE GFS HAS A WARM
TONGUE OOZING IN ACROSS THE FAR SOUTHWESTERN ZONES.
IF FOLLOWING THE NAM SOLUTION WITH A SLIGHT RELIANCE ON THE GFS
SOLUTION...THE SUB-TROPICAL FETCH OF MOISTURE WILL CONTINUE TO SPILL
ACROSS THE SOUTH PLAINS AND THUS HIGH LEVEL CLOUDINESS WILL PREVAIL
THE REST OF TODAY AND TONIGHT. A 1025 SFC RIDGE WILL SETTLE IN NE OF
THE REGION AND INDUCE GENERALLY LIGHT EAST TO SOUTHEAST/UPSLOPE SFC
WINDS TONIGHT. AS A RESULT...LOW LEVEL MOISTURE WILL INCREASE AS
MODEL SOUNDINGS DISPLAYED PROGGED PWATS NEARING 1.00 INCH
PARTICULARLY ACROSS THE CENTRAL TO EASTERN SOUTH PLAINS. THE
SYNOPTIC LIFT IS NOT STRONG AT THIS POINT...BUT CURRENT THINKING IS
THAT LOW LEVEL STRATUS WILL DEVELOP FROM SOUTH TO NORTH WITH PERHAPS
ISENTROPIC UPGLIDE BEING ENOUGH TO INDUCE LIGHT DRIZZLE ACROSS THE
AFOREMENTIONED AREAS EARLY TOMORROW MORNING. AOA 12Z...INDICATIONS
OF LOCALIZED PATCHY FOG MAY DEVELOP AND LAST THROUGH MID-MORNING
ACROSS PORTIONS OF THE CWA...AS THE SYSTEM NEARS THE WESTERN FRINGES
OF THE SOUTH PLAINS. BY EARLY AFTERNOON...SYNOPTIC LIFT HAS
INCREASED AND MUCAPE VALUES IS ANTICIPATED TO NEAR 1000 J/KG
ESPECIALLY ACROSS EASTERN ZONES. THUS...ADEQUATE MUCAPE AND 0-6 KM
SHEAR VALUES NEARING 70 KTS MAY PROMOTE ISOLATED STRONG TO POSSIBLY
SEVERE THUNDERSTORMS WHERE HAIL IS THE PRIMARY THREAT...ACROSS
EASTERN ZONES DURING THE EARLY TO MID AFTERNOON. THE 15Z-00Z
TIME-FRAME APPEARS TO BE WHEN THE SYNOPTIC LIFT IS AT ITS
BEST...WITH A NOTICEABLE DECLINATION THEREAFTER. IT IS ALSO DURING
THE AFOREMENTIONED TIME-FRAME WHERE THE FRONT IS ANTICIPATED TO
RETREAT NORTH TO NEAR THE SOUTHEASTERN ZONES BEFORE THE PACIFIC
FRONT SWEEPS IN FROM WEST TO EAST...DRY SLOTTING THE REGION LATE
MONDAY NIGHT/EARLY TUESDAY MORNING. THUS THE OVERALL TREND APPEARS
TO BE LIGHT DRIZZLE EARLY MONDAY MORNING FOLLOWED BY INCREASING RAIN
CHANCES WITH HIGHEST POPS DISPLAYED 18Z-00Z ACROSS THE
EAST...COINCIDING WITH BEST SYNOPTIC LIFT AS THE SYSTEM COMMENCES TO
MOVE ACROSS THE REGION. THEREAFTER...PRECIP WILL DECLINE FROM WEST
TO EAST BY TUESDAY 12Z.
TEMPS OVER NIGHT TONIGHT WILL BE RELATIVELY MILD WITH MID TO UPPER
30S NORTH TO LOWER TO MID 40S SOUTH EXPECTED....AS HIGH-LEVEL
CLOUDINESS ENSUE AND EVENTUALLY LOW LEVEL STRATUS DEVELOPS. TEMPS
TOMORROW COULD BE A BIT TRICKY DEPENDING ON IF THE PACIFIC FRONT
MOVING IN FROM THE WEST DRY SLOTS THE AREA QUICKER THAN ANTICIPATED.
HOWEVER...WILL LEAN TOWARDS A RANGE OF UPPER 40S TO LOWER 50S NE TO
LOWER 60S SW AS HINTED AT BY MOS GUIDANCE.
LONG TERM...
TUES 12Z...THE COLD FRONT WILL BE NEARLY IF NOT ALL THE WAY THRU THE
FA...ALLOWING THE AREA TO DRY OUT. BY WED 06Z...SKIES WILL BE CLEAR
WITH LITTLE RESIDUAL MOISTURE LEFT IN THE LOW LVLS.
THEREFORE...EXPECT TEMPS TO FALL SOME OVERNIGHT ACROSS THE AREA.
THOUGH AS SRLY SFC FLOW RETURNS...THE SHORTWAVE RIDGING ALSO MOVES
INTO THE AREA. THIS WILL ALLOW FOR A BRIEF WARMING TREND AHEAD THE
NEXT UL TROF EXPECTED TO MOVE INTO THE REGION ON TURKEY DAY. THIS
TROF IS PROGGED TO BE FAIRLY LOW AMPLITUDE AS IT MOVE ACROSS THE FA
PREVENTING MUCH IN THE WAY OF MOISTURE RETURN. THEREFORE...WILL
CONTINUE THE DRY EXTENDED FORECAST. ALSO...WINDS ASSOCIATED WITH
THIS SYSTEM LOOK FAIRLY ROBUST /AOA 40KTS AT 850/ AND GIVEN DRY
CONDITIONS THERE CONTINUE TO BE SOME FIRE WEATHER CONCERNS. THAT
BEING SAID GIVEN THE TIMING CURRENTLY PROGGED THESE WINDS WILL RAMP
UP IN THE COLD AIR AND LATE IN THE DAY AS THE TROF PUSHES THRU THE
REGION. ALSO...AS THE TROF EXITS THE REGION A SECOND SURGE OF ENERGY
TRAVERSES THE TROF PUSHING A STRONG COLD FRONT THRU THE AREA
OVERNIGHT FRI.
MEADOWS
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 36 55 34 60 31 / 10 30 20 0 0
TULIA 35 51 36 60 32 / 20 50 20 0 0
PLAINVIEW 36 52 37 61 33 / 20 50 20 0 0
LEVELLAND 41 60 40 63 34 / 20 30 10 0 0
LUBBOCK 41 54 40 63 34 / 20 40 20 0 0
DENVER CITY 44 63 42 64 36 / 20 20 10 0 0
BROWNFIELD 43 62 41 63 36 / 20 30 10 0 0
CHILDRESS 36 49 39 65 36 / 20 70 40 0 0
SPUR 42 50 41 64 37 / 20 60 20 0 0
ASPERMONT 45 53 44 63 37 / 20 70 40 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93/14
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1010 AM PST Sat Nov 19 2011
.SYNOPSIS...
A cold front boundary moving in from the Northeast and will
produce cooler and drier weather just North of the largest threat
of snow moving into eastern Washington and north central Idaho
today. Following a break in the weather Sunday, unsettled weather
will return for most of next week with most of the snow expected
to occur near the cascades and northern mountains.
&&
.DISCUSSION...
The forecast has been updated to increase snow accumulations over
the Spokane and Coeur D`Alene areas this afternoon. Morning radar
imagery shows a band of light to moderate snow entering the metro
area from the south. Warm advection in the 850-700mb layer appears
to be occurring over southeast Washington and adjacent portions of
north Idaho. Radar imagery suggests a small scale/low level
circulation enhancing the band of snow this morning as it moves
into the metro area. Spotter reports over the Palouse and traffic
cameras suggest a quick 1 to 3 inches of snow occurring with this
band. The numerical models have not resolved this small band and
there is a good deal of uncertainty on how far to the northeast it
will move this afternoon. I would expect that it would weaken or
stall over Spokane/Kootenai counties this afternoon since the more
organized circulation at 500mb remains well west of this small
snowband. As of 10am, water vapor imagery suggests that the
vorticity center with the more organized 500mb wave is around over
the southern or central Cascades. This feature will move into
eastern Washington this afternoon and early this evening, and will
likely produced more organized bands of snow somewhere between
Spokane and Lewiston. The latest RUC runs hit the northern Palouse
with another couple inches of snow by early evening. A winter
weather advisory may be needed for afternoon/evening snow
accumulations once the axis of heaviest snowfall can be
determined. /GKoch
&&
.AVIATION...
18z TAFS: Small scale bands of light to moderate snow will bring a
wide range of visibility and ceiling conditions to eastern
Washington and north Idaho through late evening. Snow bands are
not being resolved particularly well in the Spokane area, so the
18z TAFS were based on satellite and radar extrapolations which
may not be very good beyond 21z. Look for a lot of ammendments
today as the environment is fairly unstable and will produce some
highly localized bands of snow. Light winds, fresh precipitation
and high low level relative humidity will bring the potential for
low fog and stratus late Saturday night into Sunday morning.
Ceiling and visibility forecasts in this type of environment is
tough so forecast confidence is low. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 12 30 16 37 31 / 80 20 10 20 50 70
Coeur d`Alene 26 12 30 14 37 29 / 60 20 10 20 60 70
Pullman 30 17 32 18 37 32 / 70 40 10 10 30 50
Lewiston 35 22 37 26 44 34 / 60 50 10 10 20 40
Colville 30 10 29 13 33 29 / 10 10 10 20 60 70
Sandpoint 25 10 29 12 35 30 / 10 20 20 20 70 70
Kellogg 25 15 28 16 33 27 / 70 30 20 10 50 70
Moses Lake 31 10 32 17 38 26 / 60 10 10 10 30 60
Wenatchee 32 13 31 23 36 29 / 40 10 10 30 40 70
Omak 32 6 31 14 33 22 / 10 10 10 20 60 70
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
936 PM CST SUN NOV 20 2011
.UPDATE...EARLY EVENING PILOT REPORT HAD LOW LEVEL CLOUD
THICKNESS OVER 2K FEET OVER MSN BUT 00Z GRB SOUNDING SHOWS
MOISTURE DEPTH MUCH THINNER...LESS THAN 1K FT. RECENT AMDAR ASCENT
SOUNDING OVER KORD HAD FAIRLY STRONG INVERSION ABV 3K FT. 11-3.9
MICRON IMAGERY AND SFC OBS SHOW LOW CLOUD EDGE DISSIPATING A BIT
IN SOUTHWEST CWA AROUND KEFT. CLOUDS HAD BEEN DISSIPATING IN SPOTS
EARLIER IN SOUTHEAST WI...BUT NORTHEAST ONSHORE FLOW IN THE LOW
LEVELS AND DELTA-T AROUND 9-10 DEGREES HAS CAUSED LOW CLOUDS TO
FILL IN AND SPREAD TO THE WEST. RUC13 1000-900MB RH APPEARS TO BE
CATCHING THIS TREND AND CONTINUES TO SPREAD HIGHER RH WWD INTO
SOUTH CENTRAL WI. LOW LEVEL FLOW CONTINUES TO BACK TO THE EAST
OVERNIGHT REDUCING FETCH AND WEAK LOW LEVEL CONVERGENCE. HENCE LOW
CLOUDS MAY BEGIN TO THIN AND TURN SCT IN THE SOUTHEAST LATE TNGT
OR MON MRNG...AS WELL AS OVER PORTIONS OF SOUTH CENTRAL WI. WL CONTINUE
TREND OF M/CLDY WORDING AND BUMP UP TEMPS A DEGREE OR TWO IN THE
EAST.
&&
.AVIATION/06Z TAFS/...MOIST NE TO E FLOW SHOULD CONTINUE TO
PRODUCE MVFR CIGS OVER TAF SITES FOR SEVERAL MORE HOURS. LOW LEVEL
FLOW TURNS MORE ELY REDUCING LAKE EFFECT FETCH AND
CONVERGENCE...WHICH MAY ALLOW CEILINGS TO RISE LATER THIS MRNG.
MORE LOW CLOUDS AND POSSIBLE MVFR CIGS TO SPREAD BACK INTO SRN WI
TNGT AHEAD OF SYSTEM PASSING BY TO THE SOUTH.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
MBK
PREVIOUS FORECAST DISCUSSION ISSUED AT 304 PM...
THE MAIN FOCUS GOING INTO MID WEEK IS ON THE POTENTIAL FOR RAIN ON
TUESDAY AS A STORM SYSTEM MOVES THROUGH THE REGION.
CURRENTLY...A RIDGE OF HIGH PRESSURE EXTENDS FROM SOUTHERN ONTARIO
TOWARD SOUTHERN MINNESOTA. SOME LOW LEVEL STRATUS HAS LINGERED
ACROSS MUCH OF THE REGION TODAY DUE TO MOISTURE STUCK UNDER A
900MB INVERSION ON THE SOUTHEAST SIDE OF THIS RIDGE. THIS STRATUS
HAS BEEN SLOW TO ERODE TODAY WITH THE CORE OF THIS RIDGE SHIFTING
EAST INTO THE GREAT LAKES..THOUGH IT HAS LOOKED A BIT MORE
CELLULAR ON THE LAST FEW VISIBLE SCANS. WITH INCREASING LOW LEVEL
SUBSIDENCE...SKIES ARE EXPECTED TO CLEAR FROM WEST TO EAST THIS
EVENING WITH 20.18Z RUC FORECAST SOUNDINGS SHOWING THE LOW LEVEL
RH DECREASING THIS EVENING. THOUGH SKIES MAY BRIEFLY CLEAR THIS
EVENING...ADDITIONAL MID TO UPPER LEVEL CLOUD COVER IS EXPECTED TO
MOVE IN TONIGHT AHEAD OF A WEAK MID TO UPPER LEVEL WAVE THAT WILL
LIFT OUT OF THE SOUTHERN PLAINS AND HELP TO BRING SKY COVER BACK UP.
THE FOCUS THEN GOES TO TUESDAY AS A CLOSED LOW CURRENTLY ALONG THE
CALIFORNIA COAST PROPAGATES THROUGH THE FOUR CORNERS REGION TOMORROW
BEFORE ENDING UP NEAR THE SOUTHERN GREAT LAKES ON TUESDAY. THE
TREND WITH THE 20.12Z GUIDANCE HAS BEEN TO GO TOWARD HAVING A
STRONGER MID LEVEL TROUGH COME THROUGH THAT BRINGS RAIN TO THE
REGION. THE 20.12Z NAM AND ECMWF ARE THE FIRST TWO FORMS OF
GUIDANCE TO SHOW THIS PROGRESSION WHILE THE 20.12Z GFS KEEPS THE
BULK OF THE PRECIPITATION TO THE SOUTHEAST. THE PATH OF THE
SURFACE LOW DOES NOT LOOK MUCH DIFFERENT THAN WHAT PREVIOUS RUNS
HAVE SHOWN...BUT THE STRONGER MID LEVEL TROUGH LEADS TO A LARGER
AREA OF MID LEVEL QG FORCING AND IN TURN A LARGER AREA OF
PRECIPITATION. THOUGH SURFACE TEMPERATURES ARE EXPECTED TO BE IN
THE 30S TO LOW 40S...20.12Z NAM BUFKIT SOUNDINGS LOOK WARM ENOUGH
IN THE LOWEST 4KFT TO KEEP THE PRECIPITATION TYPE AS RAIN FOR THIS
EVENT. AT THIS POINT...IT APPEARS THAT RAIN WOULD START UP TUESDAY
MORNING AND END BY TUESDAY EVENING.
OTHER THAN THAT...TEMPERATURES WILL REMAIN SEASONAL IN THE 40S
FOR HIGHS AND 20S FOR LOWS WITH WEAK LOW LEVEL WARM AIR ADVECTION
EXPECTED THROUGH MID WEEK. 850MB TEMPERATURES WILL GRADUALLY RISE
FROM -2C TONIGHT TO AROUND 1C ON MONDAY...THEN TO 3-5C ON
WEDNESDAY AS A WARMER AIR MASS BEGINS TO SPREAD INTO THE REGION.
.LONG TERM...WEDNESDAY NIGHT INTO SUNDAY
304 PM CST SUN NOV 20 2011
CONDITIONS ARE LOOKING IDEAL FOR THE START OF THE HOLIDAY TRAVEL
SEASON WITH WARM SOUTHWESTERLY FLOW SETTING UP WEDNESDAY NIGHT
INTO FRIDAY WITH A SURFACE RIDGE IN THE SOUTHEAST US AND THE NEXT
LOW PRESSURE SYSTEM FORMING IN SOUTHERN CANADA. PERHAPS THE ONLY
CONCERN IS WITH HOW WINDY IT WILL BE ON THANKSGIVING WITH 20.12Z
GFS SOUNDINGS SHOWING SOUTH TO SOUTHWEST WINDS OF AROUND 15-17KTS
IN THE HIGHER TERRAIN WITH GUSTS UP TO AROUND 25-30KTS. BEYOND
THIS...925-850MB MOISTURE TRANSPORT WILL BE ON THE INCREASE AHEAD
OF THE NEXT TROUGH AND COLD FRONT THAT WILL MOVE INTO THE REGION
ON FRIDAY. THERE ARE SOME TIMING DIFFERENCES BETWEEN THE 20.12Z
GFS AND ECMWF WITH THE GFS BRINGING THIS PRECIPITATION AND FRONT
IN FASTER THAN THE ECMWF. THE ECMWF ALSO SPINS UP A SECONDARY
SURFACE LOW ON FRIDAY NIGHT INTO SATURDAY AND LINGERS THE
PRECIPITATION LONGER THAN WHAT THE GFS SHOWS. AT THIS POINT IT
APPEARS THAT THE THERMAL PROFILE WOULD BE WARM ENOUGH TO KEEP THE
PRECIPITATION TYPE IN ALL LIQUID FORM UNTIL PERHAPS THE VERY END
OF THE EVENT WHEN THE COLDER AIR MOVES IN.
&&
.AVIATION...TONIGHT AND MONDAY
806 PM CST SUN NOV 20 2011
UPDATE...CEILINGS HAVE LOWERED TO IFR AT KRST...POSSIBLY DUE TO
NOCTURNAL COOLING AND WINDS TURNING TO AN UPSLOPE-TYPE DIRECTION.
HAVE AMENDED THE KRST TAF TO HOLD THE IFR CEILIGNS THROUGH THE
NIGHT. THERE IS A POSSIBILITY CEILINGS COULD DROP TO LIFR...BUT
CONFIDENCE IS TOO LOW TO INCLUDE RIGHT NOW.
545 PM DISCUSSION...
MAIN CONCERN OF THE AVIATION FORECAST CONTINUES TO BE ON CEILINGS
AND THE LINGERING MVFR STRATUS OVER THE TAF SITES...AND BASICALLY
ALL OF WISCONSIN TOO. DAYTIME MIXING DURING THE DAY WAS NOT ENOUGH
TO MIX OUT THE STRATUS SO CONCERN NOW IS THAT THE STRATUS COULD
HANG AROUND ALL NIGHT. LOW LEVEL WINDS ARE IN THE PROCESS OF
VEERING TOWARDS THE EAST IN RESPONSE TO HIGH PRESSURE MOVING INTO
NORTHERN WISCONSIN. AN EAST WIND SHOULD HOLD THE STRATUS IN PLACE.
AFTER 06Z...925MB WINDS VEER TO THE SOUTH...WHICH COULD HELP TO
BRING IN SOME DRIER AIR SITUATED AROUND I-80 AND CLEAR OUT THE
STRATUS. ACKNOWLEDGED THIS BY SCATTERING OUT THE CLOUDS NEAR 12Z
AT BOTH KLSE AND KRST. THESE SOUTH WINDS WILL START BRINGING MORE
MOISTURE INTO THE AREA...THOUGH...ESPECIALLY AT KRST. THIS
MOISTURE IN CONJUNCTION WITH DAYTIME HEATING COULD RESULT IN A
BROKEN MVFR DECK AGAIN AT KRST AROUND 18Z.
OUTSIDE OF THE STRATUS ISSUE...PLAN ON VFR VISIBILTIES TO CONTINUE
AND WITH WINDS UNDER 10 KT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
304 PM CST SUN NOV 20 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH/AJ
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
225 PM CST SAT NOV 19 2011
.SHORT TERM...
1156 AM CST SAT NOV 19 2011
FORECAST IS GENERALLY ON TRACK. HAVE MADE SOME CHANGES BASED ON
LATEST RADAR...OBSERVATIONS...AND SHORT TERM MODEL GUIDANCE.
STALLED FRONTAL BOUNDARY CURRENTLY LIES FROM MARSHFIELD WI TO LA
CROSSE WI TO NEAR MASON CITY WITH AIR IN THE 30S TO ITS NORTH AND
MID 40S TO ITS SOUTH. DMX RADAR THIS MORNING HAD AN ERUPTION OF
DRIZZLE OVER NORTH-CENTRAL IOWA...MAINLY N OF HIGHWAY 20...AND
FREEZING DRIZZLE BACK IN NWRN IA IN THE COLDER AIR. THIS WAS IN WARM
CLOUD AREA SEEN ON IR SATELLITE IMAGERY /0 TO -10C/ LINING UP ON
THE NWRN EDGE OF THE FORECAST AREA FROM MEDFORD TO ROCHESTER MN TO
NEAR KFSD. THIS LACK OF UPPER CLOUD AND ONLY SURFACE-BASED 2KM
SATURATION WILL LEAD TO ALL LIQUID CLOUDS WITH VERTICAL MOTION
CAUSING DRIZZLE THIS AFTERNOON.
LATEST MESO MODELS AND RUC SUGGEST WARM AIR ADVECTION TO KICK IN
THIS AFTERNOON AS 295K SURFACE HAS GOOD UPGLIDE ISENTROPICALLY.
THIS WAS LEADING TO THE WIDESPREAD DRIZZLE FORMATION OVER IA AND
ECHO INCREASE OVER THE ENTIRE AREA IN THE LAST HOURS. BELIEVE
DRIZZLE WILL DOMINATE THE AREA SOUTH OF THE DEEP COLD IR CLOUD
TOPS THIS AFTERNOON AND THUS HAVE UPDATED TO HAVE THE ENTIRE AREA
GET WET WITH DRIZZLE. IN THE VERY NORTHWEST FORECAST AREA...KRST-
KMDZ..THE DEEP ICE CLOUD WILL TRY TO WORK SOUTHEAST AND PRVIDE SNOW
CHANCES LATE WITH DEEP CLOUD PROCESSES. BOTTOM LINE...A CLOUDY
AFTERNOON WITH DRIZZLE...AND A MIX AT TIMES LATER OF SNOW IN THE
NWRN FORECAST AREA.
THIS EVENING COULD GET INTERESTING FOR THE AREAS IMMEDIATELY ON
THE SOUTHEAST EDGE OF THE DEEP CLOUD. WE HAVE SOME CONCERN FOR
FREEZING DRIZZLE AS THE SURFACE LOW...NOW NEAR KANSAS CITY
MO...WILL TRACK EAST AND DRAG COLDER AIR IN FROM THE NW. THUS...DRIZZLE
MAY BECOME FREEZING DRIZZLE ALONG AND NORTH OF HIGHWAY 10 IN
WI...AND 3-4 COUNTIES EAST OF I-35 IN MN AND IA. IF DEEP CLOUD IS
IN PLACE...PRECIPITATION WILL BE SNOW. BUT WITH CURRENT SCENARIO...AND
WARM CLOUD TOPS /0 TO -10C/ IN PLACE...FZDZ COULD CAUSE SOME ICE
ACCUMULATIONS AS THE LIFT DIMINISHES AND THE STORM SHIFTS AWAY. WE
HAVE INCLUDED THIS IN THE LATEST GRIDS/FORECASTS...AND MAY HAVE TO
CONSIDER AN ADVISORY SHOULD CONFIDENCE GROW IN ACCUMS OF ICE. IT
WOULD NOT BE MUCH...BUT ENOUGH TO IMPACT TRAVELERS.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
225 AM CST SAT NOV 19 2011
A SHORT WAVE TROUGH IS EXPECTED TO LIFT OUT OF THE DESERT
SOUTHWEST AND TRAVEL TOWARD THE OHIO RIVER VALLEY EARLY IN THE
PERIOD. THE SURFACE LOW IS ALSO EXPECTED TO TRACK TROUGH THE OHIO
VALLEY BUT THERE IS SOME DIFFERENCES AS TO HOW FAR NORTH THE
PRECIPITATION SHIELD WILL GET. THE ECMWF IS THE FARTHEST NORTH AND
JUST BRUSHES THE SOUTHERN PARTS OF THE FORECAST AREA WHILE THE GFS
AND 19.00Z GEM ARE WELL TO THE SOUTH. WILL STAY WITH THE MODEL
CONSENSUS GRIDS WHICH KEEPS THIS PRECIPITATION SOUTH OF THE AREA.
AFTER THAT...IT LOOKS LIKE IT WILL BE LATE IN THE WEEK BEFORE THE
NEXT SYSTEM COMES IN AND BRINGS A CHANCE FOR SOME RAIN FRIDAY.
&&
.AVIATION...THROUGH 18Z SUNDAY
1156 AM CST SAT NOV 19 2011
TAF FORECASTS WERE ON TRACK AND HAVE MADE LITTLE CHANGE WITH 18Z.
CEILINGS WILL SLOWLY COME DOWN INTO IFR TODAY AS LOW PRESSURE AND
LIFT HEAD INTO THE TAF AREA. WIDESPREAD DZ WILL OCCUR AND SHOULD
TEMPERATURES FALL IN THE EARLY EVENING AND ENOUGH DRIZZLE
REMAIN...SOME FZDZ IS POSSIBLE NEAR KRST. ICING WOULD BE ONLY A
FEW HUNDRETHS...BUT POSSIBLE. IFR CEILINGS WILL BE PESKY TO MOVE
OUT...ESPECIALLY AT KRST...SUNDAY MORNING. LATER FORECASTS CAN
REFINE THIS TIMING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...PRELIMINARY HEADLINES FOR THIS
EVENING BASED ON FREEZING DRIZZLE AND LIGHT ICE ACCUMULATION.
223 PM CST SAT NOV 19 2011
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR WIZ017-029-032>034.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR MNZ079-086>088-094-095.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR IAZ008-009-018-019.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...04
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1157 AM CST SAT NOV 19 2011
.SHORT TERM...
1156 AM CST SAT NOV 19 2011
FORECAST IS GENERALLY ON TRACK. HAVE MADE SOME CHANGES BASED ON
LATEST RADAR...OBSERVATIONS...AND SHORT TERM MODEL GUIDANCE.
STALLED FRONTAL BOUNDARY CURRENTLY LIES FROM MARSHFIELD WI TO LA
CROSSE WI TO NEAR MASON CITY WITH AIR IN THE 30S TO ITS NORTH AND
MID 40S TO ITS SOUTH. DMX RADAR THIS MORNING HAD AN ERUPTION OF
DRIZZLE OVER NORTH-CENTRAL IOWA...MAINLY N OF HIGHWAY 20...AND
FREEZING DRIZZLE BACK IN NWRN IA IN THE COLDER AIR. THIS WAS IN WARM
CLOUD AREA SEEN ON IR SATELLITE IMAGERY /0 TO -10C/ LINING UP ON
THE NWRN EDGE OF THE FORECAST AREA FROM MEDFORD TO ROCHESTER MN TO
NEAR KFSD. THIS LACK OF UPPER CLOUD AND ONLY SURFACE-BASED 2KM
SATURATION WILL LEAD TO ALL LIQUID CLOUDS WITH VERTICAL MOTION
CAUSING DRIZZLE THIS AFTERNOON.
LATEST MESO MODELS AND RUC SUGGEST WARM AIR ADVECTION TO KICK IN
THIS AFTERNOON AS 295K SURFACE HAS GOOD UPGLIDE ISENTROPICALLY.
THIS WAS LEADING TO THE WIDESPREAD DRIZZLE FORMATION OVER IA AND
ECHO INCREASE OVER THE ENTIRE AREA IN THE LAST HOURS. BELIEVE
DRIZZLE WILL DOMINATE THE AREA SOUTH OF THE DEEP COLD IR CLOUD
TOPS THIS AFTERNOON AND THUS HAVE UPDATED TO HAVE THE ENTIRE AREA
GET WET WITH DRIZZLE. IN THE VERY NORTHWEST FORECAST AREA...KRST-
KMDZ..THE DEEP ICE CLOUD WILL TRY TO WORK SOUTHEAST AND PRVIDE SNOW
CHANCES LATE WITH DEEP CLOUD PROCESSES. BOTTOM LINE...A CLOUDY
AFTERNOON WITH DRIZZLE...AND A MIX AT TIMES LATER OF SNOW IN THE
NWRN FORECAST AREA.
THIS EVENING COULD GET INTERESTING FOR THE AREAS IMMEDIATELY ON
THE SOUTHEAST EDGE OF THE DEEP CLOUD. WE HAVE SOME CONCERN FOR
FREEZING DRIZZLE AS THE SURFACE LOW...NOW NEAR KANSAS CITY
MO...WILL TRACK EAST AND DRAG COLDER AIR IN FROM THE NW. THUS...DRIZZLE
MAY BECOME FREEZING DRIZZLE ALONG AND NORTH OF HIGHWAY 10 IN
WI...AND 3-4 COUNTIES EAST OF I-35 IN MN AND IA. IF DEEP CLOUD IS
IN PLACE...PRECIPITATION WILL BE SNOW. BUT WITH CURRENT SCENARIO...AND
WARM CLOUD TOPS /0 TO -10C/ IN PLACE...FZDZ COULD CAUSE SOME ICE
ACCUMULATIONS AS THE LIFT DIMINISHES AND THE STORM SHIFTS AWAY. WE
HAVE INCLUDED THIS IN THE LATEST GRIDS/FORECASTS...AND MAY HAVE TO
CONSIDER AN ADVISORY SHOULD CONFIDENCE GROW IN ACCUMS OF ICE. IT
WOULD NOT BE MUCH...BUT ENOUGH TO IMPACT TRAVELERS.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
225 AM CST SAT NOV 19 2011
A SHORT WAVE TROUGH IS EXPECTED TO LIFT OUT OF THE DESERT
SOUTHWEST AND TRAVEL TOWARD THE OHIO RIVER VALLEY EARLY IN THE
PERIOD. THE SURFACE LOW IS ALSO EXPECTED TO TRACK TROUGH THE OHIO
VALLEY BUT THERE IS SOME DIFFERENCES AS TO HOW FAR NORTH THE
PRECIPITATION SHIELD WILL GET. THE ECMWF IS THE FARTHEST NORTH AND
JUST BRUSHES THE SOUTHERN PARTS OF THE FORECAST AREA WHILE THE GFS
AND 19.00Z GEM ARE WELL TO THE SOUTH. WILL STAY WITH THE MODEL
CONSENSUS GRIDS WHICH KEEPS THIS PRECIPITATION SOUTH OF THE AREA.
AFTER THAT...IT LOOKS LIKE IT WILL BE LATE IN THE WEEK BEFORE THE
NEXT SYSTEM COMES IN AND BRINGS A CHANCE FOR SOME RAIN FRIDAY.
&&
.AVIATION...THROUGH 18Z SUNDAY
1156 AM CST SAT NOV 19 2011
TAF FORECASTS WERE ON TRACK AND HAVE MADE LITTLE CHANGE WITH 18Z.
CEILINGS WILL SLOWLY COME DOWN INTO IFR TODAY AS LOW PRESSURE AND
LIFT HEAD INTO THE TAF AREA. WIDESPREAD DZ WILL OCCUR AND SHOULD
TEMPERATURES FALL IN THE EARLY EVENING AND ENOUGH DRIZZLE
REMAIN...SOME FZDZ IS POSSIBLE NEAR KRST. ICING WOULD BE ONLY A
FEW HUNDRETHS...BUT POSSIBLE. IFR CEILINGS WILL BE PESKY TO MOVE
OUT...ESPECIALLY AT KRST...SUNDAY MORNING. LATER FORECASTS CAN
REFINE THIS TIMING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
225 AM CST SAT NOV 19 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...04
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1149 AM CST SAT NOV 19 2011
.UPDATE...WIDESPREAD DRIZZLE ONGOING THIS MORNING OVER IOWA AND SOUTHWEST
WISCONSIN IS ASSOCIATED WITH SATURATED LAYER AND ISENTROPIC LIFT IN
THE MID LEVELS...AS SEEN ON 290-295 K SURFACES IN LATEST RUC RUN.
WARM AIR ADVECTION OVER SOUTHERN WISCONSIN WILL CONTINUE INTO LATE
AFTERNOON...WHILE MOISTURE INCREASES IN THE AREA AS WELL.
THUS...INCREASED POPS FOR THIS AFTERNOON...BRINGING LIKELY VALUES TO
ALL BUT SOUTHERNMOST COUNTIES BY 21Z.
&&
.AVIATION/18Z TAFS/...CIGS STILL EXPECTED TO LOWER TO MVFR THIS
AFTERNOON...POSSIBLY IFR AT TIMES THIS EVENING AND INTO THE NIGHT
AS LOW PRESSURE MOVES THROUGH. AREAS OF DRIZZLE ALSO EXPECTED
DURING THIS TIME...WITH A FEW SHOWERS ALSO POSSIBLE. SOUTHERLY
WIND WILL EVENTUALLY SHIFT TO WEST BY AROUND MIDNIGHT...THEN
NORTHERLY BY DAYBREAK AS THE LOW MOVES EAST. LOOKS LIKE MVFR CIGS
MAY HOLD ON THROUGH SUNDAY MORNING...MAYBE INTO THE AFTERNOON IN
THE EAST.
&&
.PREV DISCUSSION... /ISSUED 304 AM CST SAT NOV 19 2011/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
A COLD FRONT STRETCHES FROM NORTHWEST WISCONSIN...BACK SOUTHWEST
ACROSS IOWA INTO NORTHERN KANSAS EARLY THIS MORNING. A LOW
PRESSURE SYSTEM WILL MOVE QUICKLY UP ALONG THIS FRONT OUT OF
KANSAS BY MID DAY AND TRACK ACROSS THE MIDDLE OF THE FORECAST AREA
LATE THIS AFTERNOON AND EARLY THIS EVENING. THE CENTER OF THE LOW
SHOULD TRACK PRETTY CLOSE TO MADISON...OR BETWEEN MADISON AND
WISCONSIN DELLS.
FAIRLY DEEP WARM ADVECTION AHEAD OF THE LOW KICKS IN THIS MORNING
AND AFTERNOON...ACCOMPANIED BY DECENT UVV FROM A SHORT WAVE
TRACKING ACROSS NORTHERN MN AND WI. THIS PRODUCES A NICE FOCUSED
AREA OF Q-VECTOR CONVERGENCE THAT MOVES THROUGH THE AREA BETWEEN
ABOUT 18-01Z TODAY. MOISTURE SOUTH OF THE LOW TRACK IS FAIRLY
SHALLOW AND PRECIP STILL LOOKS CHCY...ESPECIALLY WHEN VIEWING THE
QPF OUTPUT OF THE NCEP WRF-NMM. AMOUNTS SHOULD BE SPLOTCHY AND
LIGHT.
NORTH OF THE LOW...ACROSS THE NW AND NRN CWA...WILL KEEP THE
LIKELY POPS GOING. AS THE FORCING PUSHES EAST QUICKLY THIS
EVENING...THE ISENTROPIC DOWNGLIDE IS PRETTY IMPRESSIVE AND SHOULD
HELP TO SHUT THINGS DOWN QUICKLY. DRY AIR PUSHES IN ALONG WITH
COLDER TEMPS. THE PRECIP SHOULD BE GONE BEFORE ANY TEMPS DROP
BELOW FREEZING.
SHORT TERM...SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.
HIGH PRESSURE IS EXPECTED TO SHIFT EAST ACROSS THE REGION SUNDAY
AND SUNDAY NIGHT...WITH ANOTHER HIGH TO THE WEST SLOWLY MOVING
EAST THROUGH THE REGION MONDAY AND MONDAY NIGHT. NEARLY ZONAL
UPPER LEVEL FLOW DEPICTED BY MODELS. SOME MID LEVEL CLOUDS SHOULD
PUSH NORTHEAST INTO THE AREA SUNDAY AND SUNDAY NIGHT...LINGERING
INTO MONDAY BEFORE SHIFTING OFF TO THE EAST.
MODELS HAVE A WEAK VORTICITY MAXIMUM SHIFTING THROUGH THE AREA
MONDAY...WITH THE GFS AND CANADIAN MODELS SHOWING LIGHT QPF ACROSS
PORTIONS OF THE AREA. THE NAM AND ECMWF ARE DRY WITH THIS FEATURE.
GFS SHOWING MORE SATURATION IN THE LOW LEVELS THAN THE NAM AS
WELL. FOR NOW...WILL KEEP FORECAST DRY GIVEN UNCERTAINTY AMONG
THE MODELS WITH MOISTURE FIELDS MONDAY.
TEMPERATURES WILL REMAIN NEAR SEASONAL NORMALS DURING THIS
PERIOD...WITH HIGHS WARMING INTO THE MID 40S MONDAY...FROM THE
LOWER 40S SUNDAY. LOWS IN THE UPPER 20S TO MID 30S SUNDAY NIGHT
AND MONDAY NIGHT SEEM REASONABLE.
LONG TERM...TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM.
ECMWF AND GFS SHOWING SOME DIFFERENCES WITH LOW PRESSURE MOVING
NORTHEAST INTO THE MID MISSISSIPPI RIVER VALLEY AND TO THE
NORTHEAST TUESDAY AND TUESDAY NIGHT. THE ECMWF TAKES THE LOW FROM
SOUTHWEST MISSOURI TO SOUTHERN INDIANA TUESDAY...THEN QUICKLY EAST
NORTHEAST OF THERE TUESDAY NIGHT. SOUTHERN STREAM SHORTWAVE TROUGH
MOVES NORTHEAST AND CLIPS THE AREA. THIS SYSTEM CLIPS THE
SOUTHEAST HALF OF THE AREA WITH LIGHT QPF.
THE GFS IS FURTHER SOUTHEAST OF THIS TRACK...AND ANY QPF WITH
THIS SYSTEM MISSES THE AREA. BOTH THE ECMWF AND GFS SHOW SPLIT
UPPER LEVEL FLOW...WITH SHORTWAVE TROUGHS IN THE NORTHERN AND
SOUTHERN STREAMS GRADUALLY MERGING WELL EAST OF THE AREA BY 12Z
WEDNESDAY. WILL CONTINUE TO MENTION LOW POPS IN THE FAR SOUTHEAST
FOR TUESDAY. THESE SYSTEMS TEND TO SHIFT FURTHER TO THE NORTHWEST
WITH TIME...SO HIGHER POPS IN FUTURE FORECASTS MAY BE POSSIBLE.
ECMWF/GFS THEN IN FAIR AGREEMENT WITH UPPER LEVEL RIDGE SHIFTING
THROUGH THE REGION WEDNESDAY THROUGH THANKSGIVING DAY...WITH A
DEEP UPPER TROUGH FORMING IN THE SOUTHERN ROCKIES/SOUTHERN HIGH
PLAINS FRIDAY. THIS ALLOWS HIGH PRESSURE TO PASS SOUTH OF THE
REGION WEDNESDAY...WITH WARM AIR ADVECTION KICKING IN
WEDNESDAY...AND ESPECIALLY THANKSGIVING DAY AND FRIDAY. QUIET
WEATHER IS EXPECTED AT THIS TIME.
TEMPERATURES WILL WARM ABOVE SEASONAL NORMALS AS WELL WITH THE
WARM AIR ADVECTION. 925MB TEMPERATURES SHOULD INCREASE TO 9 TO 10
DEGREES CELSIUS THANKSGIVING DAY AND FRIDAY WITH GOOD MIXING.
THUS...HIGHS TO AT LEAST THE MID 50S SEEM REASONABLE FOR THIS
PERIOD.
AVIATION/12Z TAFS/...
LOW PRESSURE WILL BRING SOME SHOWERS TO SOUTHERN WISCONSIN THIS
AFTERNOON AND EVENING...DIMINISHING QUICKLY FROM WEST TO EAST BY
AROUND MIDNIGHT TONIGHT. WARM...MOIST ADVECTION WILL BRING
GRADUALLY LOWERING CIGS THIS AFTERNOON. THE SOUTHEAST TAF SITES
SHOULDN/T GET BELOW MVFR. BUT MADISON WILL BE CLOSER TO THE LOW
CENTER AND THIS SHOULD ALLOW FOR A PERIOD OF IFR CIGS LATER THIS
AFTERNOON AND EVENING. DRY AIR PUSHES IN OVERNIGHT AND WILL
IMPROVE CONDITIONS BY SUNDAY MORNING.
MARINE...
BRISK SOUTH WINDS AHEAD OF AN APPROACHING LOW PRESSURE CENTER
EXPECTED TO TRACK THROUGH SOUTH CENTRAL WISCONSIN THIS EVENING
WILL RESULT IN SMALL CRAFT ADVISORY CONDITIONS TODAY THROUGH ABOUT
MIDNIGHT TONIGHT. WEAKER WESTERLY WINDS BEHIND THE LOW WILL HELP
TO DIMINISH WAVES QUICKLY OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643>646.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
SUNDAY THROUGH FRIDAY...WOOD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
311 AM CST MON NOV 21 2011
.SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
&&
.DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN25/33
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1139 PM CST SUN NOV 20 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SURFACE RIDGING AND CLOUD COVER HAVE PREVENT TEMPS FROM WARMING UP
MUCH THIS AFTERNOON. 20Z SURFACE OBS CONTINUE TO SHOW COLD AIR
ADVECTING FROM THE NORTH WITH THE CENTER OF THE RIDGE OVER SOUTHERN
MN. ALOFT...WATER VAPOR SHOWS A CLOSED LOW OVER THE CA COAST AND
PROFILER DATA INDICATES A FAST SOUTHWEST FLOW OVER THE FORECAST AREA
WITH NO OBVIOUS WAVE WITHIN THE FLOW. HOWEVER THE RUC AND NAM
INDICATE A WEAK WAVE AT 700 MB MOVING ACROSS NORTHEAST KANSAS LATE
THIS AFTERNOON AND THIS EVENING. THIS MAY BE THE CAUSE OF THE
ENHANCED CLOUD COVER AND WEAK ECHOS ON RADAR ACROSS WESTERN KS.
THINK THAT THIS WILL NOT AMOUNT TO MUCH FOR TONIGHT DUE TO MID LEVEL
DRY AIR. MODELS SHOW THIS PASSING EAST WITH GENERAL SUBSIDENCE
TAKING OVER FOR MUCH OF THE NIGHT. ADDITIONALLY ISENTROPIC SURFACES
ARE NOT SHOWING MUCH LIFT EITHER. THEREFORE WILL CONTINUE WITH A DRY
FORECAST. CLOUD COVER COULD BE A LITTLE TRICKY TONIGHT AND HAVE A
LARGE EFFECT ON MIN TEMPS. THERE IS A GENERAL CONSENSUS THAT THE LOW
LEVEL RH OVER SOUTHERN MO AND SOUTHEAST KS WILL LIFT NORTH THROUGH
NORTHEAST KS OVERNIGHT. MEANWHILE SKIES COULD BECOME MOSTLY CLEAR
OVER CENTRAL KS. WITH THIS IN MIND HAVE DROPPED LOWS INTO THE LOWER
20S FROM MHK WEST AND LEFT LOWS IN THE LOWER 30S OVER FAR EASTERN KS
WHERE LOW CLOUDS ARE LIKELY TO HANG IN A LITTLE LONGER. FOR MONDAY
THINK TEMPS WILL WARM INTO THE MID 40S DUE TO NEUTRAL TEMP ADVECTION
AND SOME INSOLATION DURING THE DAY. MID LEVEL MOISTURE IS EXPECTED
TO BEGIN ADVECTING NORTH BY MONDAY AFTERNOON AS THE CLOSED LOW ON
THE WEST COAST MAKES ITS WAY OVER THE SOUTHERN ROCKIES. HAVE
INCLUDED SOME SLIGHT CHANCE POPS SOUTH OF I-70 DURING THE AFTERNOON
BECAUSE OF THIS.
WOLTERS
UPPER WAVE CONTINUES EAST AND NORTHEAST WHILE DEEPENING MONDAY
NIGHT. UPPER JET STREAKS FLANKING THE AREA TO THE NORTHEAST AND
SOUTHWEST INTO THE EVENING WITH DRY SLOT WORKING THROUGH SOUTHERN
KANSAS AND SOMEWHAT OF A WEAK TROWAL POKING INTO NORTHEAST KANSAS.
THERE REMAINS SOME DIFFERENCES ON THE TIMING OF THE SYSTEM WITH THE
12Z NAM ON THE FASTER END...BUT STILL APPEARS LATE EVENING THROUGH
EARLY MORNING TUESDAY WILL BE ON THE WET SIDE. DRY SLOT WILL HELP
AID CONVECTIVE CHANCES AND INSTABILITY STILL ENOUGH FOR THUNDER
INCLUSION FOR MUCH OF THE AREA. ALSO SOME CONCERN FOR FREEZING
PRECIP LATE IN THE EVENT AS SURFACE LOW PRESSURE MOVES THROUGH
SOUTHERN MISSOURI AND NORTH WINDS TAKE HOLD. WILL INTRODUCE A
FREEZING RAIN MENTION IN THE NORTHWEST. TUESDAY AFTERNOON AND NIGHT
BRING RAPIDLY IMPROVING CONDITIONS AS UPPER RIDGING BUILDS IN.
AIRMASS BEHIND THE SYSTEM NOT TERRIBLY COLD WITH DOWNSLOPE WINDS TO
THE NORTHWEST SO HIGHS SHOULD STILL REACH THE LOWER 50S TUESDAY AND
ON INTO THE UPPER 50S WEDNESDAY UNDER CLEAR SKIES AND INCREASING
SOUTH WINDS.
65
EXTENDED FORECAST (WEDNESDAY NIGHT THROUGH SUNDAY)
SOUTHERLY FLOW...WARM AIR ADVECTION AND UPPER LEVEL RIDGING WILL
RETURN TO THE CENTRAL U.S. ON THANKSGIVING DAY. HIGH TEMPERATURES
ARE EXPECTED TO QUICKLY REBOUND INTO THE LOW 60S. SOUTH WINDS WILL
BE STRONG AND GUSTY ON THANKSGIVING DAY WITH A STRONG PRESSURE
GRADIENT BETWEEN A SURFACE HIGH OVER THE SOUTHEASTERN U.S. AND
SURFACE LOW FORMING ALONG THE ROCKY MOUNTAINS. MODELS ARE INDICATING
A LONGWAVE TROUGH WILL MOVE OUT OF THE ROCKY MOUNTAINS ON FRIDAY
ALONG WITH THE SURFACE LOW AND COLD FRONT. ENOUGH ELEVATED
INSTABILITY WILL EXIST AHEAD OF THE APPROACHING FRONT FOR A FEW
THUNDERSTORMS DURING THE DAY ON FRIDAY.
MODELS QUICKLY DIVERGE INTO NEXT WEEKEND. THE OPERATIONAL GFS AND
DGEX BRING THE COLD FRONT THROUGH THE CWA FRIDAY NIGHT AND THEN
CLOSE OFF AN UPPER LEVEL LOW OVER THE MID-MISSISSIPPI RIVER VALLEY.
THE 12Z ECMWF BRINGS THE FRONT THROUGH THE CWA SATURDAY MORNING BUT
THEN CLOSES THE UPPER LEVEL LOW OFF IN NORTHEASTERN OKLAHOMA. THE
ECMWF SOLUTION WOULD KEEP PRECIPITATION CHANCES IN THE FORECAST FOR
THE MAJORITY OF HOLIDAY WEEKEND. FOR THE FORECAST HAVE FAVORED THE
MORE PROGRESSIVE SOLUTIONS OF THE GFS AND DGEX WITH MANY OF THE GFS
ENSEMBLES INDICATING A MORE PROGRESSIVE UPPER LEVEL WAVE.
ANDERSON
&&
.AVIATION...
MVFR STRATUS WILL CONTINUE ACROSS KTOP AND KFOE THROUGH 15Z
MONDAY...WITH CEILINGS OF 1200 TO 1600 FEET. KMHK MAY REMAIN AT OR
ABOVE VFR CEILINGS THROUGH THE NIGHT...THOUGH THEY MAY DROP BELOW
3,000 FEET AT TIMES DURING THE NIGHT. THE LOWER STRATUS SHOULD MIX
OUT BY MID MORNING...THEN REDEVELOP TONIGHT AS ISENTROPIC LIFT
INCREASES ACROSS THE TAF SITES. MAY SEE LIGHT RAIN DEVELOPING AT
KMHK BY LATE EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1047 PM CST SUN NOV 20 2011
.AVIATION...06Z TAF. VFR CONDITIONS WILL BE IN PLACE AT THE START
OF THE TAF PERIOD. 11-3.9 MICRON SATELLITE IMAGERY SHOWS STRATUS
LOCATED ACROSS PARTS OF CENTRAL AND NORTHEAST KANSAS THAT HAS BEEN
SLOWLY MIGRATING NORTH. THE LATEST RUC SUGGESTS THE CLOUDS SHOULD
NOT MAKE IT AS FAR NORTH AS KGRI...SO WILL KEEP THOSE OUT OF THE
FORECAST FOR NOW. ATTENTION THEN SHIFTS TO AN UPPER LEVEL
DISTURBANCE THAT WILL MOVE INTO PARTS OF KANSAS MONDAY NIGHT.
AHEAD OF THE DISTURBANCE...MID AND HIGH LEVEL CLOUDS WILL
INCREASE...AND WILL SHOW A MID LEVEL CEILING FORMING AROUND 22Z.
WINDS WILL STAY LIGHT AND VARIABLE TONIGHT...BUT SHOULD TURN TO A
SOUTH/SOUTHEASTERLY DIRECTION LATE MONDAY MORNING INTO MONDAY
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 303 PM CST SUN NOV 20 2011/
SHORT TERM...TONIGHT THROUGH MONDAY. MAIN FORECAST CONCERN WILL BE
TEMPERATURES.
SATELLITE AND OBSERVATION INDICATES THAT CIRRUS CONTINUES TO SPREAD
ACROSS THE CENTRAL PLAINS THIS AFTERNOON. TEMPERATURES HAVE HAD A
LITTLE STRUGGLE TO CLIMB TODAY...BUT STILL ARE MAKING SOME PROGRESS.
SURFACE ANALYSIS HAS A RIDGE OF HIGH PRESSURE FROM MINNESOTA THROUGH
KANSAS...WHICH IS HELPING TO KEEP WINDS LIGHT AND TEMPERATURES COOL
ACROSS THE AREA.
THE SURFACE HIGH PRESSURE SYSTEM MOVES OFF TO THE EAST TONIGHT.
WINDS WILL GRADUALLY TURN TO THE SOUTH AND THERE IS A LITTLE WARM
ADVECTION ACROSS THE AREA DURING THE NIGHT. DESPITE THE WARM
ADVECTION TEMPERATURES SHOULD BE CLOSE TO WHAT THEY WERE LAST NIGHT
BUT MAYBE BIT WARMER. ON MONDAY THERE IS MORE WARM ADVECTION AND
TEMPERATURES ALOFT START TO WARM UP. EXPECT TEMPERATURES TO WARM UP.
AS THE SURFACE HIGH MOVES FURTHER EAST WINDS WILL TURN TO THE SOUTH.
THIS WILL HELP WARM THINGS UP...BUT WILL ALSO BRING SOME RETURN
MOISTURE AHEAD OF THE NEXT UPPER LEVEL WAVE THAT APPROACHES MONDAY
AFTERNOON. WILL CONTINUE TO KEEP THINGS DRY MONDAY AFTERNOON...BUT
THERE WILL BE AN INCREASE IN CLOUDS ACROSS THE AREA DURING THE DAY.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. MAIN CONCERN IN THE
EXTENDED WILL BE TEMPERATURE SWINGS ALONG WITH A COUPLE OF SMALL
CHANCES FOR PRECIPITATION.
LOOKING AT THE BIG PICTURE...VARIOUS EXTENDED MODELS SEEM TO BE IN
DECENT AGREEMENT OVER THE NEXT WEEK. THE FIRST SYSTEM WE WILL HAVE
TO DEAL WITH IS THE CLOSED MID LEVEL LOW PRESSURE JUST MOVING ONTO
THE PACIFIC COAST NEAR SFO. LATEST OPERATIONAL RUNS OF THE GFS AND
EC ALONG WITH ENSEMBLE SOLUTION CONTINUE TO SHOW THIS FEATURE
BECOMING MORE OF AN OPEN WAVE AS IT MOVES EAST OVER THE ROCKIES. THE
BEST FORCING AND MOISTURE LOOKS TO STAY SOUTH OF OUR CWA AS THIS
WAVE SWINGS THROUGH MONDAY NIGHT. SURFACE WINDS WILL SWITCH TO THE
NORTH AS SURFACE LOW TO OUR SOUTH MOVES EAST USHERING IN ANOTHER
BATCH OF COLDER AIR. THIS COULD BE AN ISSUE IN THE SOUTH AND
SOUTHEAST PART OF THE CWA AS FORECAST SOUNDINGS SHOWING AT LEAST A
SMALL CHANCE THAT ANY PRECIPITATION WE DO GET COULD BE IN THE FORM
OF FREEZING RAIN. THERE ARE STILL SOME QUESTIONS ABOUT THAT BUT
SINCE WE ALREADY HAVE A SLIGHT CHANCE OF FREEZING RAIN GOING IN THE
FORECAST...WILL NOT CHANGE ATTM. THIS LOOKS TO BE A QUICK HITTING
SYSTEM AND OPTED TO END PRECIP CHANCES BY 12Z TUESDAY. THE 09Z & 15Z
RUNS OF THE SREF MODEL STILL HANGING ONTO POPS IN THE SOUTH AND
SOUTHEAST DURING THE DAY ON TUESDAY BUT SEEMS TO ME IT IS LINGERING
THE PRECIP TOO FAR BEHIND THE TROUGH AXIS OF THE MID LEVEL WAVE.
AFTER THAT...TUESDAY AFTERNOON THROUGH THANKSGIVING LOOKING VERY
NICE ACROSS THE CENTRAL PLAINS AS A BROAD MID LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE ROCKIES AND CENTRAL PLAINS. HIGH TEMPERATURES
ON WED AND THU SHOULD BE IN THE UPPER 50S TO MID 60S...OR AROUND 10
TO 15 DEGREES ABOVE NORMAL FOR THIS TIME OF THE YEAR. THE ONLY
THING KEEPING THANKSGIVING FROM BEING A PERFECT DAY WILL BE THE
WINDS WHICH COULD BE A BIT GUSTY OUT OF THE SOUTH AS THE SURFACE
PRESSURE GRADIENT TIGHTENS UP OVER THE CWA DUE TO HIGH PRESSURE TO
OUR SOUTHEAST AND LOW PRESSURE DEVELOPING OVER THE LEE OF THE
ROCKIES.
RIDGE BEGINS TO BREAK DOWN FRIDAY AS NEXT SYSTEM APPROACHES THE
WESTERN U.S. COAST. ACTUALLY IT LOOKS LIKE A COUPLE OF SYSTEMS...ONE
MOVING INTO THE NORTHWEST AND ONE FURTHER SOUTH. THE EC IS PHASING
THESE SYSTEMS AS THEY MOVE EAST...PUSHING A HIGH AMPLITUDE TROUGH
ACROSS THE PLAINS FRIDAY NIGHT INTO THE WEEKEND. AT THIS TIME THE
MODELS PRODUCING MOST OF THE PRECIP TO OUR EAST BUT COULD BE SOME
LIGHT RAIN FRIDAY/FRIDAY NIGHT. THE BIGGER IMPACT WILL BE THE HIGH
TEMPERATURES WHICH WILL DROP BACK TO SEASONAL LEVELS BY NEXT
WEEKEND.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1041 PM CST SUN NOV 20 2011
.AVIATION.../FOR THE 00Z TAFS/
VFR CONDITIONS EXPECTED THROUGH 00Z TUESDAY WITH OCCASIONAL CEILINGS
NEAR BKN100-120. ONE CONCERN THAT NEEDS TO BE WATCHED WILL BE A
SLOWLY EXPANDING AREA OF STRATUS OVER SOUTHEAST MINNESOTA. WITH
LIGHT FLOW BELOW THE INVERSION THIS COULD CONTINUE TO ADVECT WEST
AND WHILE MORE THAN LIKELY GET STUCK ALONG AND EAST OF THE BUFFALO
RIDGE WILL ENCROACH FAIRLY CLOSELY TO SUX AND FSD FROM ABOUT 10Z TO
13Z. /08
&&
.DISCUSSION...
TOUGH UPDATE TONIGHT WITH WARM AIR ADVECTION AND CLOUD COVER
INCREASING ACROSS THE AREA OVERNIGHT. TEMPERATURES HAVE NOT FALLEN
MUCH THROUGH THE EVENING HOURS...AND HAVE BEGUN TO CREEP UPWARDS IN
A FEW LOCATIONS. HAVE LEFT SOME BREATHING ROOM ON THE BOTTOM END
FOR LOWS TONIGHT IN CASE LOCATIONS ARE ABLE TO DECOUPLE OVER THE
NEXT FEW HOURS...BUT IF THIS DOESN/T OCCUR EXPECT TO SEE A GENERAL
UPWARD TREND IN TEMPERATURES. BEST CHANCE OF DECOUPLING WILL BE IN
THE FAR EAST WHERE THE UPPER RIDGE WILL HANG ON FOR A FEW MORE
HOURS. SPEAKING OF THE EAST...STRATUS ALONG I-90 HAS SURGED BACK TO
JUST TO THE WEST OF ALBERT LEA MN AS OF 2Z. RUC SUGGESTS THIS IS
GOING TO CONTINUE TO BACK TO THE WEST THROUGHOUT THE NIGHT.
CEILINGS WITHIN STRATUS ARE FAIRLY LOW AND AM CONCERNED ABOUT FOG
POTENTIAL...BUT AFTER COLLABORATING WITH NEIGHBORING OFFICES TO THE
EAST OPTED TO LEAVE MENTION OUT OF THE FORECAST FOR NOW. INCREASED
SKY COVER IN FAR EAST..BUT THINK THE STRATUS WILL FIGHT WARM AIR
ADVECTION AND DRY AIR TO THE WEST AND WILL STRUGGLE ADVANCING MUCH
FURTHER WEST THAN FAR EASTERN TIER OF COUNTIES. UPDATE POSTED.
&&
.DISCUSSION.../ISSUED AT 307 PM CST/
MAIN FORECAST PROBLEM TONIGHT WILL BE LOW TEMPERATURES WHICH WILL
LIKELY OCCUR BEFORE MIDNIGHT BEFORE WARM AIR ADVECTION KICKS IN
ALONG WITH SOME INCREASE IN MID AND HIGH CLOUDS. WITH TEMPERATURES
IN TEENS AND 20S MOST PLACES THIS AFTERNOON...WILL NOT HAVE FAR TO
FALL WITH LIGHT WINDS...SO WILL GO LOWER THAN GUIDANCE...ESPECIALLY
SNOW COVERED AREAS...WITH STEADY OR SLOWLY RISING TEMPERATURES AFTER
MIDNIGHT AS LOW LEVEL SOUTHEASTERLY WINDS INCREASE.
A TREND OF SLOW WARMING WILL CONTINUE THROUGH LATE AFTERNOON ON
MONDAY...BUT WITH DECREASING WINDS IN THE EVENING...TEMPERATURES
WILL LIKELY DROP OFF QUICKLY BEFORE MIDNIGHT. HOWEVER...THE WARMER
AND MORE MOIST AIRMASS THAT WILL ADVECT INTO THE REGION ON MONDAY
SHOULD PREVENT OVERNIGHT LOWS FROM BOTTOMING OUT MUCH BELOW AVERAGE.
FOR THE REMAINDER OF THE WORK WEEK...TEMPERATURES WILL GENERALLY BE
ABOVE AVERAGE AS ZONAL FLOW BUILDS INTO A LONGWAVE RIDGE ACROSS THE
CENTRAL PLAINS. A SPLIT DISTURBANCE WILL MOVE THROUGH THE REGION ON
TUESDAY...BUT SHOULD NOT IMPACT THE FORECAST AREA EXCEPT FOR A
SLIGHT INCREASE IN CLOUD COVER ACROSS THE SOUTHEASTERN CORNER OF THE
CWA.
ON FRIDAY...A DEEP TROUGH WILL MOVE THROUGH THE REGION...BRINGING A
SURFACE COLD FRONT ACROSS THE PLAINS BY FRIDAY EVENING. CURRENTLY
PRECIPITATION CHANCES LOOK LOW...ESPECIALLY ACROSS THE WESTERN HALF
OF THE REGION WHERE FRONTAL PASSAGE WILL OCCUR EARLIER IN THE DAY
AND THE TEMPERATURE GRADIENT WILL NOT BE QUITE AS IMPRESSIVE.
MOISTURE WILL ALSO BE QUITE LIMITED EVEN AS THE FRONT MOVES THROUGH
NW IA AND SW MN...SO LEFT THE CHANCE OF PRECIPITATION FAIRLY LOW
THROUGHOUT THE EVENT. AFTER THE SYSTEM EXITS THE AREA ON SATURDAY
MORNING...TEMPERATURES WILL BRIEFLY RETURN TO NORMAL VALUES...WITH
NO ADDITIONAL PRECIPITATION EXPECTED THROUGH THE FORECAST PERIOD.
/LAFLIN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1153 PM CST SUN NOV 20 2011
.DISCUSSION...
SEE AVIATION FOR 06Z TAF DISCUSSION.
&&
.AVIATION...
LOW CLOUD FORMATION IS AHEAD OF SCHEDULE AS A WEAK COLD FRONT
CONTINUES TO CREEP SOUTHWARD TO NEAR A T82 TO GTU LINE AT 05Z.
GIVEN THIS TREND AND THE RUC SHOWING A SLIGHT PUSH FARTHER SOUTH
BEFORE RETREATING...WILL SHOW A NEAR FRONTAL ENVIRONMENT AT AUS
WITH SOME PATCHY DRIZZLE POSSIBLE FROM 12Z-18Z. CIGS JUST BEHIND
THE FRONT ARE RUNNING AT SIMILAR VALUES TO THOSE AHEAD OF THE
FRONT...BUT DEEPER INTO THE FRONTAL LAYER CIG HEIGHTS BECOME
MOSTLY IFR/LIFR OVER WEST CENTRAL TX. THUS WILL OFFER A 500 FT
CIG AND EXPECT SOME FLUCTUATIONS A FEW HUNDRED FEET WITH PATCHY
FOG AND DRIZZLE. SOUTH OF THE FRONT DRT/SAT/SSF SITES SHOULD
CONTINUE TO SEE A NEAR PERSISTENCE PATTERN OF MAINLY MFVR CIGS IN
THE OVERNIGHT HOURS THROUGH THE EARLY AFTERNOON. THE CENTRAL TX
FRONT IS EXPECTED TO DRIFT NORTHWARD WITH INCREASED LATE MORNING
SOUTHERLIES. AREAS OF SHOWERS ARE EXPCTED TO BE SIMILAR TO THAT OF
TODAY...AND A FEW THUNDERSTORMS COULD BECOME POSSIBLE AGAIN AFTER
22/00Z OVER THE NORTHERN HILL COUNTRY AS THE WEAK FRONT IS STILL
EXPECTED TO BE OVER CENTRAL TX.
&&
.PREV DISCUSSION... /ISSUED 922 PM CST SUN NOV 20 2011/
UPDATE...
MADE A QUICK UPDATE TO BRING BRING INTO THE FAR NRN CWA. LOADED
RUC WINDS INTO THE GRIDS WHICH HAS THE FRONT STALLING ACROSS THE
ONE COUNTY INTO THE NRN CWA OVERNIGHT. OTHERWISE ONGOING FORECAST
IN GOOD SHAPE.
PREV DISCUSSION... /ISSUED 301 PM CST SUN NOV 20 2011/
DISCUSSION...
MOIST...SOUTHEAST FLOW OFF THE GULF CONTINUES TONIGHT IN RESPONSE
TO PROGRESSIVE MOVE OF UPPER TROUGH INTO SOUTHERN/BAJA CALIFORNIA
ARIZONA. A FEW SHOWERS MAY DEVELOP OVER THE NORTHEAST CORRIDOR
TONIGHT...EITHER THIS EVENING IN RESIDUAL ISOLATED DAYTIME
INSTABILITY SHOWERS/SOUTHWARD PROPAGATION OF EXISTING STORMS IN
CENTRAL TEXAS OR CONVERGENT LATE NIGHT SHOWERS. LOWS TONIGHT WILL
RANGE FROM THE LOWER 60S HILLS TO THE LOW 70S ALONG THE I-35
CORRIDOR. THE APPROACHING TROUGH WEAKENS WHILE SWEEPING EASTWARD
ACROSS WEST AND NORTH TEXAS TOMORROW. STILL WEAK CAPPING ALOFT AND
RICH GULF MOISTURE IN THE LOWER LEVELS WILL RESULT IN SCATTERED
SHOWERS MAINLY HILL COUNTRY AND NORTHERN AREAS TOMORROW. HIGHS IN
THE UPPER 70S HILLS TO LOW AND MID 80S ADJACENT AREAS...EXCEPT
UPPER 80S SOUTHWEST. MODELS IN UNISON ON BRINGING A COLD FRONT
INTO THE AREA LATE TOMORROW NIGHT AND PUSHING IT SOUTHEAST OF THE
REGION BY MIDDAY TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL LINE THE FRONT LATE MONDAY NIGHT AND TUESDAY
MOST NUMEROUS OVER THE NORTHEAST CORRIDOR WHERE DYNAMICS AND
INSTABILITIES WILL BE BEST. A FEW STORMS MAY APPROACH SEVERE
LIMITS OVER NORTHERN PORTIONS OF THE HILL COUNTRY MONDAY NIGHT.
SHORT WAVE RIDGE PATTERN ALOFT SHIFTS EAST WITH A DRY SURFACE
RIDGE BUILDING SOUTH WEDNESDAY. LOW LEVEL MOISTURE WILL INCREASE
AHEAD OF THE NEXT SYSTEM ON THANKSGIVING WITH INCREASING CLOUDINESS.
HIGHS THANKSGIVING WILL BE MOSTLY IN THE 70S...LOWS GENERALLY IN
THE 40S WITH A FEW 30S HILL COUNTRY. AS THE SYSTEM PUSHES INTO
NORTHWEST TEXAS ON FRIDAY...A PACIFIC COLD FRONT WILL SLIDE INTO
WESTERN PORTIONS OF THE REGION. SHOWERS AND STORMS WILL AGAIN FORM
ALONG AND AHEAD OF THE FRONT FRIDAY AND FRIDAY NIGHT. A STRONGER
COLD FRONT WILL ARRIVE OVERNIGHT FRIDAY INTO EARLY SATURDAY
MORNING WITH CLEARING SKIES AND COLDER TEMPERATURES THROUGH NEXT
WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 72 82 67 80 50 / 20 30 60 30 -
AUSTIN BERGSTROM INTL AIRPORT 72 83 67 81 45 / 20 30 60 30 -
NEW BRAUNFELS MUNI AIRPORT 71 83 64 81 46 / 10 20 50 30 -
BURNET MUNI AIRPORT 68 79 64 77 47 / 30 40 60 20 -
DEL RIO INTL AIRPORT 64 82 59 81 47 / - 10 20 - -
GEORGETOWN MUNI AIRPORT 70 80 67 78 47 / 30 30 60 30 -
HONDO MUNI AIRPORT 67 84 63 83 43 / - 20 40 20 -
SAN MARCOS MUNI AIRPORT 72 82 66 79 47 / 10 20 50 30 -
LA GRANGE - FAYETTE REGIONAL 72 83 69 80 50 / 10 20 50 40 10
SAN ANTONIO INTL AIRPORT 70 83 66 81 49 / 10 20 40 30 -
STINSON MUNI AIRPORT 70 85 67 83 50 / - 20 40 30 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...01
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1131 PM CST SUN NOV 20 2011
.DISCUSSION...
KLBB HAS SLIPPED INTO IFR CONDITIONS WHILE KCDS REMAINS MVFR...BUT
IS EXPECTED TO SLOWLY DECREASE INTO IFR THROUGH EARLY MONDAY
MORNING. ALSO EXPECT TO SEE CHANCES FOR RAIN INITIALLY START OFF
AS DRIZZLE OR SHOWERS...BUT AS A STRONG STORM SYSTEM APPROACHES...
EXPECT TO SEE PRECIPITATION START TO INCREASE IN INTENSITY AND
COVERAGE THROUGH MONDAY MORNING. CANNOT RULE OUT SOME STRONG
STORMS AT THE TAF SITES WITH THE POSSIBILITY OF HAIL BUT IT
REMAINS TOO EARLY TO TELL WHEN OR WHERE THIS WILL OCCUR.
LIKEWISE...DO NOT EXPECT TO SEE CONTINUOUS PERIODS OF
PRECIPITATION BUT COVERAGE SHOULD BE ENOUGH TO WARRANT PREVAILING
CONDITIONS...AT LEAST FOR NOW. PRECIPITATION SHOULD DECREASE IN
INTENSITY AND CONDITIONS SHOULD IMPROVE BACK INTO THE MVFR RANGE
LATE IN THE AFTERNOON FROM WEST TO EAST AS THE STORM SYSTEM
DEPARTS THE AREA AND DRIER AIR WORKS INTO THE AREA FROM THE WEST.
VFR WILL RETURN TO KLBB BEFORE MIDNIGHT TUESDAY BUT JUST BEYOND
THE END OF THIS TAF CYCLE FOR KCDS.
JORDAN
&&
.AVIATION...
&&
.PREV DISCUSSION... /ISSUED 541 PM CST SUN NOV 20 2011/
AVIATION...
DIFFICULT FORECAST FOR THE TAF SITES FOR THE NEXT 24 TO 36 HOURS.
MVFR CEILINGS ARE EXPECTED TO DEVELOP AT BOTH TAF SITES SOMETIME
TONIGHT BUT THE EXACT TIME REMAINS HIGHLY UNCERTAIN. NEXT ISSUE IS
THE POSSIBILITY OF DRIZZLE AND/OR FOG DEVELOPMENT AT BOTH TAF SITES
WHICH WILL ALSO HELP TO BRING VISIBILITIES DOWN. OVERALL...IT
APPEARS THAT VFR-MVFR CONDITIONS WILL HOLD THROUGH MIDNIGHT LOCAL
TIME AND THEN GRADUALLY START TO DECREASE DOWN INTO IFR RANGE BY
SUNRISE AT BOTH SITES. IFR/MVFR CONDITIONS THEN EXPECTED TO
PERSIST INTO TOMORROW AS RAIN CHANCES INCREASE WITH THE APPROACH
OF A STORM SYSTEM FROM THE WEST. CONFIDENCE IN TIMING FOR ONSET OF
PRECIPITATION IS ALSO VERY LOW BUT EXPECT PRECIP CHANCES TO
PERSIST THROUGH MONDAY AFTERNOON. MAY SEE SOME BRIEF IMPROVEMENT
INTO SOLID MVFR RANGE LATE IN THE DAY MONDAY. EXPECT AMENDMENTS AS
CONDITIONS START TO EVOLVE THROUGH TONIGHT AND AS NEW WEATHER
INFORMATION ARRIVES.
JORDAN
PREV DISCUSSION... /ISSUED 247 PM CST SUN NOV 20 2011/
SHORT TERM...
MAIN FOCUS FOR THE SHORT TERM PERIOD IS THE IMPENDING WEST COAST
SYSTEM THAT WILL BRING CHANCES OF RAIN COMMENCING TOMORROW...AND
TAMPERING OFF TUESDAY MORNING.
THE PACIFIC UA LOW SYSTEM OF INTEREST WAS LOCATED OFF THE COAST OF
CENTRAL CALIFORNIA PER 20Z WATER VAPOR IMAGERY...AND PROGGED TO OPEN
UP AND EJECT QUICKLY ESE TO ACROSS THE DESERT SOUTHWEST MONDAY
MORNING...ACROSS THE SOUTH PLAINS MONDAY NIGHT AND EAST OF THE
REGION TUESDAY MORNING. THIS RELATIVELY QUICK TRAJECTORY IS BEING
HANDLED WELL BY THE NAM...GFS AND ECMWF SOLUTIONS...WITH PERHAPS THE
NAM BEING A TOUCH FASTER THAN THE LATTER MODELS. 20Z SFC ANALYSIS
DISPLAYED A COLD FRONT THAT SURGED SOUTH ACROSS THE CWA EARLIER THIS
MORNING...AND WAS SPATIALLY DISTRIBUTED FROM A NEAR PINE SPRINGS TO
FORT STOCKTON TO BRADY LINE. THUS LEAVING TEMPS IN THE 40S AND 50S
AND DEWPOINTS IN THE 20S AND 30S IN ITS WAKE. THIS PLACEMENT OF THE
SAID FRONT IS FARTHER SOUTH THAN WHAT MODELS PREDICTED 24 HOURS AGO.
THE GFS AND ECMWF ARE ONLY SLIGHTLY SIMILAR TO THE NAM IN REGARD TO
THE FRONT NOT BEING QUITE AS FAR SOUTH...HENCE THE CURRENT PLACEMENT
OF THE FRONT IS NOT HANDLED WELL BY EITHER AFOREMENTIONED SOLUTION
PER SE. HENCE...THE NAM AND RUC MODELS DISPLAY THE FRONT TRANSLATING
A BIT FARTHER SOUTH TONIGHT /THE RUC IS MOST AGGRESSIVE WITH THIS
POSSIBILITY/ BUT THE NAM AND TO A LESSER EXTENT THE GFS HAS A WARM
TONGUE OOZING IN ACROSS THE FAR SOUTHWESTERN ZONES.
IF FOLLOWING THE NAM SOLUTION WITH A SLIGHT RELIANCE ON THE GFS
SOLUTION...THE SUB-TROPICAL FETCH OF MOISTURE WILL CONTINUE TO SPILL
ACROSS THE SOUTH PLAINS AND THUS HIGH LEVEL CLOUDINESS WILL PREVAIL
THE REST OF TODAY AND TONIGHT. A 1025 SFC RIDGE WILL SETTLE IN NE OF
THE REGION AND INDUCE GENERALLY LIGHT EAST TO SOUTHEAST/UPSLOPE SFC
WINDS TONIGHT. AS A RESULT...LOW LEVEL MOISTURE WILL INCREASE AS
MODEL SOUNDINGS DISPLAYED PROGGED PWATS NEARING 1.00 INCH
PARTICULARLY ACROSS THE CENTRAL TO EASTERN SOUTH PLAINS. THE
SYNOPTIC LIFT IS NOT STRONG AT THIS POINT...BUT CURRENT THINKING IS
THAT LOW LEVEL STRATUS WILL DEVELOP FROM SOUTH TO NORTH WITH PERHAPS
ISENTROPIC UPGLIDE BEING ENOUGH TO INDUCE LIGHT DRIZZLE ACROSS THE
AFOREMENTIONED AREAS EARLY TOMORROW MORNING. AOA 12Z...INDICATIONS
OF LOCALIZED PATCHY FOG MAY DEVELOP AND LAST THROUGH MID-MORNING
ACROSS PORTIONS OF THE CWA...AS THE SYSTEM NEARS THE WESTERN FRINGES
OF THE SOUTH PLAINS. BY EARLY AFTERNOON...SYNOPTIC LIFT HAS
INCREASED AND MUCAPE VALUES IS ANTICIPATED TO NEAR 1000 J/KG
ESPECIALLY ACROSS EASTERN ZONES. THUS...ADEQUATE MUCAPE AND 0-6 KM
SHEAR VALUES NEARING 70 KTS MAY PROMOTE ISOLATED STRONG TO POSSIBLY
SEVERE THUNDERSTORMS WHERE HAIL IS THE PRIMARY THREAT...ACROSS
EASTERN ZONES DURING THE EARLY TO MID AFTERNOON. THE 15Z-00Z
TIME-FRAME APPEARS TO BE WHEN THE SYNOPTIC LIFT IS AT ITS
BEST...WITH A NOTICEABLE DECLINATION THEREAFTER. IT IS ALSO DURING
THE AFOREMENTIONED TIME-FRAME WHERE THE FRONT IS ANTICIPATED TO
RETREAT NORTH TO NEAR THE SOUTHEASTERN ZONES BEFORE THE PACIFIC
FRONT SWEEPS IN FROM WEST TO EAST...DRY SLOTTING THE REGION LATE
MONDAY NIGHT/EARLY TUESDAY MORNING. THUS THE OVERALL TREND APPEARS
TO BE LIGHT DRIZZLE EARLY MONDAY MORNING FOLLOWED BY INCREASING RAIN
CHANCES WITH HIGHEST POPS DISPLAYED 18Z-00Z ACROSS THE
EAST...COINCIDING WITH BEST SYNOPTIC LIFT AS THE SYSTEM COMMENCES TO
MOVE ACROSS THE REGION. THEREAFTER...PRECIP WILL DECLINE FROM WEST
TO EAST BY TUESDAY 12Z.
TEMPS OVER NIGHT TONIGHT WILL BE RELATIVELY MILD WITH MID TO UPPER
30S NORTH TO LOWER TO MID 40S SOUTH EXPECTED....AS HIGH-LEVEL
CLOUDINESS ENSUE AND EVENTUALLY LOW LEVEL STRATUS DEVELOPS. TEMPS
TOMORROW COULD BE A BIT TRICKY DEPENDING ON IF THE PACIFIC FRONT
MOVING IN FROM THE WEST DRY SLOTS THE AREA QUICKER THAN ANTICIPATED.
HOWEVER...WILL LEAN TOWARDS A RANGE OF UPPER 40S TO LOWER 50S NE TO
LOWER 60S SW AS HINTED AT BY MOS GUIDANCE.
LONG TERM...
TUES 12Z...THE COLD FRONT WILL BE NEARLY IF NOT ALL THE WAY THRU THE
FA...ALLOWING THE AREA TO DRY OUT. BY WED 06Z...SKIES WILL BE CLEAR
WITH LITTLE RESIDUAL MOISTURE LEFT IN THE LOW LVLS.
THEREFORE...EXPECT TEMPS TO FALL SOME OVERNIGHT ACROSS THE AREA.
THOUGH AS SRLY SFC FLOW RETURNS...THE SHORTWAVE RIDGING ALSO MOVES
INTO THE AREA. THIS WILL ALLOW FOR A BRIEF WARMING TREND AHEAD THE
NEXT UL TROF EXPECTED TO MOVE INTO THE REGION ON TURKEY DAY. THIS
TROF IS PROGGED TO BE FAIRLY LOW AMPLITUDE AS IT MOVE ACROSS THE FA
PREVENTING MUCH IN THE WAY OF MOISTURE RETURN. THEREFORE...WILL
CONTINUE THE DRY EXTENDED FORECAST. ALSO...WINDS ASSOCIATED WITH
THIS SYSTEM LOOK FAIRLY ROBUST /AOA 40KTS AT 850/ AND GIVEN DRY
CONDITIONS THERE CONTINUE TO BE SOME FIRE WEATHER CONCERNS. THAT
BEING SAID GIVEN THE TIMING CURRENTLY PROGGED THESE WINDS WILL RAMP
UP IN THE COLD AIR AND LATE IN THE DAY AS THE TROF PUSHES THRU THE
REGION. ALSO...AS THE TROF EXITS THE REGION A SECOND SURGE OF ENERGY
TRAVERSES THE TROF PUSHING A STRONG COLD FRONT THRU THE AREA
OVERNIGHT FRI.
MEADOWS
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 36 55 34 60 31 / 10 30 20 0 0
TULIA 35 51 36 60 32 / 20 50 20 0 0
PLAINVIEW 36 52 37 61 33 / 20 50 20 0 0
LEVELLAND 41 60 40 63 34 / 20 30 10 0 0
LUBBOCK 41 54 40 63 34 / 20 40 20 0 0
DENVER CITY 44 63 42 64 36 / 20 20 10 0 0
BROWNFIELD 43 62 41 63 36 / 20 30 10 0 0
CHILDRESS 36 49 39 65 36 / 20 70 40 0 0
SPUR 42 50 41 64 37 / 20 60 20 0 0
ASPERMONT 45 53 44 63 37 / 20 70 40 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/93/14
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1015 PM CST SUN NOV 20 2011
.UPDATE...
THE COLD FRONT CURRENTLY LIES NEAR A LINE FROM BURNET TO GROESBECK
TO ATHENS...AND IT CONTINUES TO SLOWLY PROGRESS SOUTH. LATEST RUC
GUIDANCE PUSHES THE FRONT NEARLY COMPLETELY THROUGH THE CWA EXCEPT
FOR MAYBE PART OF ANDERSON AND LEON COUNTY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE STILL OCCURRING WELL NORTH
OF THE FRONT FROM COMANCHE NORTH TO THE RED RIVER AND EAST OF
THERE. WILL FOLLOW THE RUC GUIDANCE WITH THE FRONT POSITION AND
PUSH THE FRONT THROUGH NEARLY THE ENTIRE CWA TONIGHT AND CONTINUE
A 40-50 PERCENT CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS
OVERNIGHT. THESE SHOWERS AND STORMS ARE OCCURRING IN AN UNSTABLE
ATMOSPHERE ABOVE THE FRONT WHERE SOUTH TO SOUTHWESTERLY WINDS
CONTINUE TO BRING MOISTURE AND ISENTROPIC LIFT OVER THE SHALLOW
FRONT.
FOR THE UPDATE...ADJUSTED THE FRONTAL POSITION IN THE GRIDS AND
ALSO HAD TO ADJUST DEWPOINTS AND TEMPERATURES OVERNIGHT. OVERNIGHT
LOWS WERE LOWERED SIGNIFICANTLY IN MANY PLACES.
WITH THE FRONT ADVANCING FARTHER SOUTH THAN EXPECTED...THIS HAS
SIGNIFICANT IMPACTS ON TOMORROW/S FORECAST. AS THE UPPER LEVEL
TROUGH CURRENTLY OVER CALIFORNIA CONTINUES TO MOVE EAST
TOMORROW...SURFACE CYCLOGENESIS WILL OCCUR OVER NORTHERN MEXICO.
THIS WILL HELP TO DRAW THE FRONT BACK NORTH AS A WARM FRONT BUT IT
DOES NOT APPEAR THAT THE CYCLOGENESIS WILL BE STRONG ENOUGH TO
DRAW THE FRONT PAST THE I-20 CORRIDOR. THE NEW 00Z NAM SOLUTION
SUPPORTS THIS AND HAVE ADJUSTED THE FORECAST TO CLOSELY FOLLOW THE
NAM FOR NOW. THE NAM BRINGS THE FRONT AS FAR NORTH AS A LAMPASAS
TO CORSICANA TO CANTON LINE TOMORROW AFTERNOON. THIS WOULD MEAN
THAT ALL LOCATIONS NORTH OF THE FRONT WOULD REMAIN ENTRENCHED IN
THE COLD AIR WHILE LOCATIONS SOUTH OF THE FRONT WARMED INTO THE
80S. HAVE ADJUSTED TOMORROW/S HIGH TEMPERATURES DOWN NORTH OF THE
FRONT WITH MOST OF THIS AREA REMAINING IN THE 50S.
RAIN AND POSSIBLY THUNDERSTORMS ARE STILL EXPECTED TO OCCUR NORTH
OF THE FRONT AS THE UPPER LEVEL SUPPORT ARRIVES...BUT FORECAST
SOUNDINGS FROM THE 00Z NAM NORTH OF THE FRONT DO NOT SHOW MUCH
ELEVATED INSTABILITY. THIS MAY LIMIT THE SEVERE POTENTIAL ACROSS
MOST OF THE NORTHERN HALF OF THE CWA TOMORROW. INSTEAD...THIS
REGION COULD JUST SEE A CHILLY RAIN TOMORROW. WILL CONTINUE TO
EVALUATE THE SEVERE THREAT AND LOCATION THROUGH THE NIGHT AS MORE
MODEL DATA ARRIVES. THE LOCATION OF THE FRONT WILL AGAIN PLAY A
CRITICAL FACTOR IN TOMORROW/S CONVECTIVE AND SEVERE WEATHER
POTENTIAL.
82/JLD
&&
.AVIATION...
MULTIPLE AVIATION WEATHER CONCERNS THROUGH MONDAY AFTERNOON WITH
MVFR CEILINGS/VISIBILITIES EXPECTED THROUGH THE EVENING...BECOMING
IFR AFTER SUNRISE MONDAY AND REMAINING IFR UNTIL MID AFTERNOON.
A COLD FRONT...CURRENTLY NEAR A LAMPASAS...WACO...CORSICANA...TO
EMORY LINE...WILL REMAIN NEARLY STATIONARY OVERNIGHT AND LIFT
NORTHWARD ON MONDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE POSSIBLE NEAR AND NORTH OF THE COLD FRONT OVERNIGHT WITH
STORM CHANCES INCREASING ON MONDAY AS THE FRONT LIFTS NORTH AND
LARGE SCALE LIFT INCREASES. THE BEST THUNDERSTORM CHANCES AT ALL
TAF SITES WILL BE MONDAY AFTERNOON/MONDAY NIGHT.
A NORTH/NORTHWEST WIND WILL PREVAIL AT ALL TAF SITES OVERNIGHT AT
SPEEDS BETWEEN 6 AND 12 KNOTS ALONG WITH SOME HIGHER GUSTS THIS
EVENING. THE WIND WILL SLOWLY TURN TO THE NORTHEAST/EAST ON MONDAY
AS THE FRONT BEGINS TO LIFT NORTHWARD AND EVENTUALLY BECOME
SOUTHEAST MONDAY AFTERNOON/EVENING.
79
&&
.PREV UPDATE...
.UPDATE...
THE IMMEDIATE THREAT FOR SEVERE WEATHER IN NORTH TEXAS APPEARS TO
BE WANING AND THUS HAVE CANCELLED THE WATCH FOR ALL OF NORTH
TEXAS. EXPECT THAT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE THROUGH THE NIGHT AND SOME OF THESE MAY PRODUCE
SMALL HAIL AND NUMEROUS CLOUD TO GROUND LIGHTNING STRIKES. THE 00Z
FWD SOUNDING SHOWS THE COLD FRONT TO BE CONFINED BELOW 925 MB OR
BELOW 3000 FT. ABOVE THE COLD FRONT THE ATMOSPHERE IS UNCAPPED AND
UNSTABLE BUT WEAK LAPSE RATES AND A LACK OF SIGNIFICANT
/UPWARD FORCING BEHIND THE FRONT IS LIKELY KEEPING THE SHOWERS
AND THUNDERSTORMS BELOW SEVERE LIMITS.
THE COLD FRONT IS MAKING AN IMPRESSIVE ADVANCEMENT SOUTH AND HAS
NOW PASSED THROUGH LAMPASAS AND PARTS OF NORTHERN BELL COUNTY. THE
WESTERN PORTION OF THE FRONT HAS MORE PUSH THAN THE EASTERN
SECTION AS THE FRONT THEN DRAPES TO THE NORTHEAST TOWARDS
CORSICANA AND EMORY. THE TEMPERATURE FORECAST FOR TONIGHT HAS BEEN
ADJUSTED BASED ON THIS LATEST POSITION BUT MAY NEED TO BE ADJUSTED
AGAIN DEPENDING ON HOW FAR SOUTH THE EASTERN PORTION ADVANCES.
WITH THE FRONT FARTHER SOUTH THAN PREVIOUS FORECAST...THIS COULD
AFFECT THE CONVECTIVE FORECAST FOR TOMORROW BUT WILL NOT BE MAKING
CHANGES AT THIS TIME.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 157 PM CST SUN NOV 20 2011/
...SEVERE THUNDERSTORM POTENTIAL CONTINUES ACROSS PORTIONS OF NORTH
TEXAS LATER THIS AFTERNOON AND AGAIN ON MONDAY AFTERNOON AND
EVENING...
OVERALL...THIS AFTERNOONS FORECAST PACKAGE CONTINUES THE TRENDS
MENTIONED IN PREVIOUS FORECASTS OVER THE PAST SEVERAL DAYS. THE
COLD FRONT IS RUNNING SLIGHTLY AHEAD OF PREVIOUS TIMING...BUT
FAIRLY CLOSE TO THE NAM AND RUC MODEL SOLUTIONS. AT 145 PM IT
EXTENDS FROM PARIS TO CLEBURNE TO SOUTH OF COMANCHE.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON THROUGH MID/LATE EVENING AS FORCING FOR ASCENT ARRIVES
FROM THE WEST AND HELPS WEAKEN THE STRONG CAP AROUND 860MB. VERY
MOIST AND UNSTABLE AIR AHEAD OF THE COLD FRONT WILL PRODUCE CAPES
500-1200 J/KG THIS EVENING AND 700-1400 J/KG ON MONDAY. BULK SHEAR
0-6KM WILL BE IN THE RANGE OF 40-60 KTS BOTH DAYS ALONG WITH
HELICITY VALUES GREAT THAN 200 M2/S2. AS PREVIOUSLY STATED...LARGE
HAIL WILL BE THE PRIMARY SEVERE THUNDERSTORM THREAT FOLLOWED BY
DAMAGING WINDS AND BRIEF ISOLATED TORNADOES. AREAS TO WATCH FOR
QUICK TORNADOGENESIS ARE...WHERE SURFACE WINDS ARE BACKED AND
THOSE CELLS THAT MOVE NEAR AND ALONG THE COLD FRONT. HAVE ADDED
SEVERE WORDING TO THE ZONE PACKAGE IN THIS RELEASE.
THE SYSTEM SHOULD MOVE OUT OF NORTH TEXAS LATE TUESDAY AFTERNOON
WITH FAIR WEATHER FOR WEDNESDAY AND THANKSGIVING DAY. OUR NEXT
SYSTEM WILL ARRIVE FRIDAY WITH ANOTHER ROUND OF THUNDERSTORMS AND
BENEFICIAL RAINFALL FOR NORTH TEXAS. THIS SYSTEM WILL MOVE RIGHT
ON THROUGH THE REGION AND SHOULD BE OUT OF NORTH TEXAS LATE FRIDAY
NIGHT. AFTERWARD...IT WILL BE DRY WITH SEASONAL TEMPERATURES OVER
THE WEEKEND. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 46 74 48 69 45 / 60 60 90 40 10
WACO, TX 52 80 56 75 44 / 60 40 80 50 10
PARIS, TX 49 81 55 68 44 / 60 60 90 60 10
DENTON, TX 45 69 46 66 41 / 60 70 90 20 5
MCKINNEY, TX 45 79 46 67 43 / 60 60 90 50 10
DALLAS, TX 47 78 49 70 47 / 60 50 90 50 10
TERRELL, TX 51 83 53 70 45 / 60 50 90 50 10
CORSICANA, TX 53 82 56 75 47 / 60 40 80 70 10
TEMPLE, TX 52 84 61 77 46 / 60 40 70 60 10
MINERAL WELLS, TX 43 64 42 68 40 / 40 70 90 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
TOO. NEXT AVIATION FORECAST DISCUSSION WILL DISCUSS THIS ISSUE
MORE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
304 PM CST SUN NOV 20 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH/AJ
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1042 AM EST MON NOV 21 2011
.SYNOPSIS...
A PRESSURE RIDGE WILL BE CENTERED EAST AND SOUTH OF THE FORECAST
AREA THROUGH TUESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL
MOVE THROUGH THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ZONAL FLOW OVER REGION TODAY. RUC MODEL SHOWS A WEAK SHORT WAVE
EXITING TO THE EAST BY LATE MORNING THEN NVA EARLY THIS AFTERNOON.
HOWEVER...ANOTHER WEAK RIPPLE MOVES MAINLY IN THE NORTHERN PART OF
THE AREA LATER THIS AFTERNOON. SO WILL KEEP A 20 PERCENT CHANCE OF
SHOWERS NORTH PART THIS AFTERNOON. WEAK ISENTROPIC LIFT THROUGHOUT
TODAY SHOULD HELP MAINTAIN SOME CLOUDINESS. WE WILL REMAIN IN THE
WARM AIR MASS WITH A PRESSURE RIDGE EAST AND SOUTH OF THE FORECAST
AREA. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
THE NAM AND GFS KEEP A WARM FRONT AND ASSOCIATED DEEPER MOISTURE
NORTH OF THE FORECAST AREA THROUGH TUESDAY. A COLD FRONT
APPROACHING FROM THE WEST TUESDAY NIGHT SHOULD MOVE THROUGH THE
FORECAST AREA WEDNESDAY. NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
WILL LIKELY OCCUR MAINLY ASSOCIATED WITH THE H85 JET AHEAD OF THE
FRONT. USED THE HIGHER NAM MOS POPS. THE NAM AND GFS INDICATE H85
WINDS OF 35 TO 40 KNOTS. SEVERE THUNDERSTORMS MAY OCCUR BECAUSE OF
THE STRONG SHEAR. THE MODELS SHOW THE JET AND ASSOCIATED MOISTURE
SHIFTING EAST OF THE FORECAST AREA BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE WEDNESDAY
NIGHT THROUGH SATURDAY. THE GFS SHOWS THE PRESSURE RIDGE EXTENDING
THROUGH THE FORECAST AREA FRIDAY. THE GFS ENSEMBLE MEANS INDICATE
THE COLDEST TEMPERATURES FRIDAY MORNING AND THIS APPEARS REASONABLE
BECAUSE OF THE STRONGEST RADIATIONAL COOLING. THE GFS SHOWS A STRONG
COLD FRONT MOVING INTO THE AREA SUNDAY. THE GFS ENSEMBLE MEAN
POPS SUPPORT POPS AROUND 30 PERCENT.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
WEAK HIGH PRESSURE REMAINS OVER THE AREA WITH WSW FLOW ALOFT. EXPECT
SOME WEAK RIPPLES IN THE UPPER FLOW TODAY WHICH MAY TRIGGER A FEW
SHOWERS ACROSS THE AREA DURING THE AFTERNOON HOURS. MAINLY VFR
CONDITIONS DURING TODAY. MODELS MAINTAIN THE FOG THREAT AFTER
22/00Z...SO HAVE INCLUDED MVFR FOG AT ALL TAF SITES FROM ABOUT
22/04Z ONWARD.
EXTENDED AVIATION OUTLOOK...MVFR TO IFR CIGS/VSBYS POSSIBLE
WEDNESDAY MORNING ASSOCIATED WITH AN APPROACHING FRONTAL SYSTEM
FROM THE NORTHWEST.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...07
NEAR TERM...07
SHORT TERM...07
LONG TERM...07
AVIATION...22
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
518 AM CST MON NOV 21 2011
.UPDATE...
.AVIATION /FOR THE 12Z TAF ISSUANCE/
LIGHT AND VARIABLE WINDS WILL PERSIST THROUGH ABOUT 14-15 UTC THIS
MORNING, BEFORE DIURNAL HEATING AIDS THE DEVELOPMENT OF A PRESSURE
GRADIENT AND WINDS BECOME LIGHT SOUTHEASTERLY. SURFACE WINDS WILL
REMAIN IN THE 5-10 KNOT RANGE THROUGH THE DAY AND SLOWLY BACK TO THE
NORTH THROUGH MIDNIGHT. SLOW BOUNDARY LAYER MOISTURE ADVECTION IS
ANTICIPATED LATE IN THE PERIOD AS WELL FROM AN AIRMASS OVER OKLAHOMA
MARKED BY 30 TO 40 DEGREE DEW POINTS. WEAK LARGE SCALE ASCENT FROM
AND APPROACHING WESTERN WAVE WILL WORK WITH THIS MOISTURE TO DEVELOP
SHOWERS ACROSS THE EASTERN PORTION OF THE AREA AS EARLY AS 00-03
UTC.
&&
.PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
544 AM CST MON NOV 21 2011
.AVIATION...12Z KGRI TAF. VFR CONDITIONS ARE FORECAST. A SHORTWAVE
TROUGH MOVING INTO THE SOUTHERN PLAINS WILL LOWER CEILINGS TO MID-
LEVEL. NOT TOO FAR SOUTH OF THE TERMINAL THERE WILL BE MUCH LOWER
CEILINGS BETWEEN 06Z AND 12Z TUESDAY MORNING ALONG WITH THE
POSSIBILITY OF FREEZING RAIN. FOR NOW IT LOOKS LIKE PRECIPITATION
SHOULD REMAIN BARELY SOUTH OF THE TERMINAL...BUT CLOSE. WIND
SHOULD REMAIN LIGHT.
&&
.PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
515 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
.LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.PREV DISCUSSION... /ISSUED 1047 PM CST SUN NOV 20 2011/
AVIATION...06Z TAF. VFR CONDITIONS WILL BE IN PLACE AT THE START
OF THE TAF PERIOD. 11-3.9 MICRON SATELLITE IMAGERY SHOWS STRATUS
LOCATED ACROSS PARTS OF CENTRAL AND NORTHEAST KANSAS THAT HAS BEEN
SLOWLY MIGRATING NORTH. THE LATEST RUC SUGGESTS THE CLOUDS SHOULD
NOT MAKE IT AS FAR NORTH AS KGRI...SO WILL KEEP THOSE OUT OF THE
FORECAST FOR NOW. ATTENTION THEN SHIFTS TO AN UPPER LEVEL
DISTURBANCE THAT WILL MOVE INTO PARTS OF KANSAS MONDAY NIGHT.
AHEAD OF THE DISTURBANCE...MID AND HIGH LEVEL CLOUDS WILL
INCREASE...AND WILL SHOW A MID LEVEL CEILING FORMING AROUND 22Z.
WINDS WILL STAY LIGHT AND VARIABLE TONIGHT...BUT SHOULD TURN TO A
SOUTH/SOUTHEASTERLY DIRECTION LATE MONDAY MORNING INTO MONDAY
AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
705 AM EST MON NOV 21 2011
.SYNOPSIS...
OFFSHORE HIGH PRESSURE WILL EXTEND WESTWARD INTO EASTERN NORTH
CAROLINA THIS MORNING. A BACKDOOR COLD FRONT WILL SLIDE SOUTH
THROUGH EASTERN NORTH CAROLINA LATE TODAY AND TONIGHT THEN LIFT BACK
NORTH AS A WARM FRONT LATE TUESDAY. A COLD FRONT WILL MOVE THROUGH
FROM THE WEST LATE WEDNESDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT THURSDAY AND FRIDAY. THE HIGH WILL MOVE OFF THE COAST ON
SATURDAY. A MOIST COLD FRONT WILL APPROACH THE AREA SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM MONDAY...ADDED 20 POPS FOR ISOLD SHOWERS OVER NRN
SECTIONS THROUGH 10 AM. A FEW OBS INDICATE PCPN REACHING THE GROUND
WITH ACTIVITY CURRENTLY NE TO SW NEAR ECG-CLT LINE. ACTIVITY ASSCTD
WTIH INITIAL SHRT WV AND LATEST RUC13 ONLY MODEL TO PICK UP ON IT.
SOME BREAKS IN CLOUDS EXPECTED THIS AFTN AFTER SHRT WV MOVES THROUGH
AND STICKING WITH MAX TEMPS IN MID 70S INLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 330 AM MONDAY...LITTLE CHANGE TO PREVIOUS FCST WITH FRONT
PUSHING THROUGH BY EARLY EVENING...THEN STALLING TO S OVERNIGHT.
APPROACHING SHRT WV ACTIVITY AND DEVELOPING ISENT LIFT WILL PRODUCE
SLIGHT CHC OF PCPN OVER NRN HALF OF AREA OVERNIGHT. LATEST MOS GDNC
BLEND VERY CLOSE TO PREVIOUS FCST MIN TEMPS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 3 AM MON...MAIN FEATURE OF INTEREST FOR THE LONG TERM WILL BE
A STRONG COLD FRONT THAT WILL SWEEP THROUGH E NC ON WED. MODELS IN
VERY GOOD AGREEMENT ON SYNOPTIC REGIME THROUGH THE END OF THE WEEK.
SFC BACK DOOR COOL FRONT WILL LIFT NORTH AS A WARM FRONT ON TUE.
OVERRUNNING WILL PRODUCE A STRATUS DECK AND POTENTIALLY A SHOWER OR
TWO MAINLY FOR NORTHEASTERN SECTIONS OF THE CWA. OTHERWISE A WARM
AND HUMID DAY IS ON TAP AS THE AREA WILL BE IN THE WARM SECTOR.
SIGNIFICANT SHORT WAVE TROUGH WILL APPROACH THE AREA ON TUE NIGHT
AND MOVE THROUGH ON WED. BOTH MID AND LOW LEVEL SUPPORT WILL BE
PRESENT FOR A PERIOD OF WIDESPREAD BUT SHORT DURATION RAINFALL.
PWATS AOA 1.5 INCHES AND GOOD BNDRY LAYER MOISTURE CONVERGENCE WILL
SET THE STAGE FOR RAIN. GENERALLY A HALF INCH OF RAIN IS EXPECTED ON
AVERAGE AS THE PRECIP WILL BE QUITE PROGRESSIVE. RAIN WILL ARRIVE
AROUND SUNRISE WED AND BE THROUGH THE BULK OF THE FA...SAVE FOR THE
COASTAL WATERS AND OBX...BY SHORTLY AFTER THE NOON HOUR. WITH THE
TIMING OF THE PRECIP MOVING THROUGH IN THE MORNING...LIMITED
POTENTIAL FOR SEVERE WEATHER AS INSTABILITY WILL BE LIMITED.
KINEMATICS WILL BE THERE FOR PERHAPS AN ISO STRONGER STORM AS LOW
LEVEL/DEEP LAYER SHEAR IS QUITE STRONG. GUSTY WINDS WILL BE THE MAIN
THREAT.
RAPID DRYING OF THE COLUMN WILL FOLLOW THE FROPA...AND BY WED
NIGHT TEMPS WILL PLUMMET INTO THE 30S FOR MOST AREAS ON CLEARING
SKIES. CAA WILL CONTINUE ON THANKSGIVING DAY WITH MAX T`S IN THE
UPR 50S WITH A BRISK NNW WIND. THE COOL DOWN WILL BE SHORT
LIVED...AS SFC HIGH WILL PROGRESS THROUGH AND RETURN FLOW WILL
DEVELOP ON FRI. CONDITIONS LOOK TO REMAIN DRY THROUGH THE EARLY
PART OF THE WEEKEND...WITH MODELS DIVERGING THEREAFTER. OPER GFS
IND STRONG SHORTWAVE BREAKING OFF FROM THE NORTHERN STREAM
WESTERLIES AND BECOMING CLOSED OFF IN THE SE CONUS...WHILE NCEP
AND ECM ENSEMBLE MEANS INDICATING A CONTINUED PROGRESSIVE
PATTERN. WILL SIDE WITH THE LATTER SOLN AND KEEP A VERY LOW CHANCE
POP TO ROUND OUT THE WEEKEND.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
/SHORT TERM THROUGH MONDAY EVENING/
AS OF 645 AM MONDAY...VFR SCU AND AC WDSPRD OVER AREA EARLY THIS
MORNING EXPECTED TO CONTINUE INTO AFTN. ISOLD SHOWERS ASSCTD WITH
SHRT WV WILL AFFECT NRN HALF OF AREA NEXT FEW HOURS BUT NOT EXPECTED
TO LIMIT VSBYS. A BACK DOOR COLD FRONT WILL DRIFT SOUTH ACROSS THE
REGION LATE TODAY WITH A CHANCE FOR MVFR CEILINGS TO DEVELOP IN THE
POST FRONTAL LOW LEVEL N-NE FLOW THIS EVENING...AND IFR LIKELY
OVERNIGHT.
/LONG TERM MONDAY NIGHT THROUGH FRIDAY/...
AS OF 3 AM MON...ANY LOW STRATUS/FOG SHOULD MIX OUT TO VFR MO CLOUDY
SKIES ON TUE AS SW BNDRY LAYER FLOW INCREASES AHEAD OF COLD FRONT
APPROACHING FROM THE WEST. CONDITIONS MAY DETERIORATE TUE NIGHT AS
THE BNDRY LAYER DECOUPLES ONCE AGAIN...AND PLENTIFUL LOW LEVEL
MOISTURE IS PRESENT. THIS REGIME WOULD FAVOR A LOW STRATUS
DEVELOPMENT AS INC HIGH AND MID LEVEL CLOUDS OVERRUN THE LOW LEVEL
MOISTURE. A STRONG COLD FRONT WILL SWEEP THROUGH ON WED...WITH A PD
OF WIDESPREAD RAIN AND TEMPO IFR CONDITIONS POSSIBLE. WINDS TURN
ABRUPTLY NW BEHIND THE FRONT ON WED AFTERNOON AND COULD BE A BIT
GUSTY. NNW GUSTY WINDS ARE EXPECTED ON FRI UNDER SUNNY SKIES.
&&
.MARINE...
/SHORT TERM THROUGH TONIGHT/...
AS OF 645 AM MONDAY...ADDED ISOLATED SHOWERS OVER NRN WATERS THIS
MORNING PER NEAR TERM UPDATE. NO CHANGES TO WINDS AND WAVES.
/PREVIOUS DISCUSSION/
AS OF 330 AM MONDAY...PREVIOUS FCST GENERALLY ON TRACK WITH WINDS
AROUND 15 KT OR LESS SHFTING FROM SW-W TO N-NE LATE AFTN THROUGH
EVENING AS BACKDOOR FRONT SLIDES ACROSS AREA. DID INCREASE WINDS
SLIGHLY OVER SRN WATERS AHEAD OF FRONT TODAY...AND ALL AREAS BEHIND
FRONT LATE TONIGHT WITH SLIGHTLY STRONGER SURGE INDICATED.
UPDATED SEAS WITH MODIFIED WW3. MAIN IMPACT WILL BE SOME HEIGHTS TO
AROUND 4 FT NRN WATERS LATE TONIGHT DUE TO STRONGER SURGE.
/LONG TERM TUESDAY THROUGH FRIDAY/...
AS OF 3 AM MON...WINDS WILL SHIFT TO EAST AND THEN SE ON TUE AS
FRONT RETREATS TO THE NORTH AS A WARM FRONT. THE WINDS SHOULD BE
LIGHT DURING THE DAY. GRADIENT INC TUE NIGHT AS APPROACHING COLD
FRONT MOVES INTO THE WESTERN CAROLINAS. WINDS VEER SW AND INC TO 15
KT...INC TO 20 KT WED MORNING. COOLER NEARSHORE WATERS WILL LIMIT
MIXING AND SHOULD CAP SUSTAINED WINDS AROUND 20 KT...WHERE AS HIGHER
WINDS EXPECTED OUT TOWARDS THE GULF STREAM. SCA CONDITIONS LIKELY
ALL OF THE WATERS WITH WIND GUSTS TOPPING 25 KT AND SEAS BUILDING
ABOVE 6 FT. THE FRONT SWEEPS OFFSHORE WED EVENING WITH WINDS VEERING
TO NW. CAA WILL COMMENCE AND WIND GUSTS COULD APPROACH GALE FORCE
FOR A PERIOD LATE WED NIGHT/EARLY THUR...ESPECIALLY ACROSS THE
NORTHERN AND CENTRAL WATERS. WINDS WILL DIMINISH BELOW SCA BY FRIDAY
AS HIGH PRES APPROACHES FROM THE WEST. SEAS WILL PEAK AROUND 9 FT IN
THE NRN WATERS EARLY THUR.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
740 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY
738 AM CST MON NOV 21 2011
PROFILERS ARE INDICATING THAT THE 925 MB WINDS HAVE BECOME MORE
SOUTHERLY THIS MORNING. THIS IS ALLOWING THE LOW LEVEL MOISTURE
WHICH IS TRAPPED BELOW THE INVERSION TO STREAM NORTHWARD FROM
IOWA. THESE CLOUDS ARE MEETING UP WITH SOME LOW CLOUDS THAT WERE
ALREADY LOCATED ACROSS THE AREA. MEANWHILE FAR EASTERN IOWA AND
NORTHERN ILLINOIS HAS LITTLE LOW LEVEL MOISTURE. BASED ON
THE LATEST RUC AND NAM/WRF...THINKING THAT MUCH OF THE AREA WILL
REMAIN MOSTLY CLOUDY TODAY. THE ONLY EXCEPTIONS WILL BE ACROSS
SOUTHWEST WISCONSIN AND POSSIBLY CENTRAL WISCONSIN WHERE THERE
MAY BE SOME SUNSHINE FROM TIME TO TIME THIS MORNING AND EARLY
AFTERNOON.
A STRONG SHORT WAVE TROUGH CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST WILL EJECT OUT TO THE NORTHEAST STARTING TODAY. AS IT DOES...
IT WILL BE COMING INTO A STRONGLY CONFLUENT FLOW OVER THE OHIO
VALLEY AND NORTHEAST PART OF THE COUNTRY. THIS IS EXPECTED TO
CAUSE THE WAVE TO WEAKEN AND TO TAKE ON A POSITIVE TILT WITH A
WEAK SURFACE LOW TRACKING THROUGH THE OHIO VALLEY. THE ECMWF IS
THE STRONGEST WITH THE SURFACE WAVE BUT THE NEW 21.00Z RUN HAS
BACKED OFF SOME ON THE STRENGTH OF THE SYSTEM AND DOES NOT HAVE
THE PRECIPITATION NEARLY AS FAR NORTH. THE 21.03Z SREF MEAN IS BY
FAR THE WEAKEST WITH THIS SYSTEM AND WOULD SUGGEST THAT ONLY FAR
SOUTHERN GRANT COUNTY HAS ANY CHANCE OF GETTING SOME
PRECIPITATION. THE 21.00Z NAM AND GFS ARE IN THE MIDDLE OF THESE
WITH JUST SOME LIGHT PRECIPITATION AS FAR NORTH AS MAYBE ELKADER
TO RICHLAND CENTER. THERE IS NOT A LOT OF FORCING ON THE NORTH
SIDE OF THIS SYSTEM WITH THE NAM AND GFS SHOWING AT MOST 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ALONG WITH SOME
WEAK QG CONVERGENCE AND FRONTOGENESIS ABOVE 700 MB. WITH JUST SOME
WEAK FORCING...HAVE TRENDED THE FORECAST TOWARD THE WEAKER AND
MORE SOUTHERN SOLUTIONS AND CONFINED THE PRECIPITATION CHANCES TO
SOUTH OF A NEW HAMPTON TO ADAMS/FRIENDSHIP LINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
229 AM CST MON NOV 21 2011
STILL EXPECTING TO SEE A NICE WARM UP OCCURRING EARLY IN THE
PERIOD. HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST AND THE
RETURN LOW LEVEL FLOW WILL BRING WARMER AIR IN THE AREA. THE GFS
SUGGESTS 925MB TEMPERATURES WARMING TO AROUND 10C FOR THANKSGIVING
WITH A COLD FRONT EXPECTED TO COME ACROSS SOMETIME OVER THE
WEEKEND. THE MODELS HAVE DIVERGED ON THIS SYSTEM WITH THE ECMWF
BREAKING AWAY FROM THE CONSENSUS. THIS SYSTEM LOOKS TO BE A FULL
LONG WAVE TROUGH WITH EMBEDDED NORTHERN AND SOUTHERN STREAM SHORT
WAVE TROUGHS. THE ECMWF IS TRENDING TOWARD A STRONGER NORTHERN
STREAM SYSTEM THUS CAUSING THE LONG WAVE TROUGH TO TAKE ON A
POSITIVE TILT. IF THIS HAPPENS...THERE COULD BE LITTLE MOISTURE
RETURN AND NOT A LOT OF PRECIPITATION AS THE SYSTEM COMES THROUGH.
THE GFS AND 21.00Z GEM FOR NOW ARE HOLDING WITH THE IDEA OF THE
LONG WAVE TROUGH BEING STACKED WITH PRETTY MUCH EQUAL IN STRENGTH
NORTHERN AND SOUTHERN STREAM WAVES. THIS ALLOWS GULF MOISTURE TO
RETURN WITH SOME DECENT PRECIPITATION POSSIBLE. FOR NOW...HAVE
STAYED WITH THE NON ECMWF CONSENSUS SUGGESTING A PRETTY HIGH
PROBABILITY OF PRECIPITATION FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...TODAY AND TONIGHT
738 AM CST MON NOV 21 2011
PROFILERS ARE INDICATING THAT THE 925 MB WINDS HAVE BECOME MORE
SOUTHERLY THIS MORNING. THIS IS ALLOWING THE LOW LEVEL MOISTURE
WHICH IS TRAPPED BELOW THE INVERSION TO STREAM NORTHWARD FROM
IOWA. THESE CLOUDS ARE MEETING UP WITH SOME LOW CLOUDS THAT WERE
ALREADY LOCATED ACROSS THE AREA. THE 21.06Z NAM/WRF SEEMS TO HAVE
A GOOD HANDLE ON THESE CLOUDS AND IT SUGGESTS THAT BOTH TAFS SITE
WILL LIKELY CONTINUE TO SEE A MVFR DECK THROUGH THIS EVENING...
AND THEN MAY BECOME IFR OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
738 AM CST MON NOV 21 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 AM CST MON NOV 21 2011
.SHORT TERM...THROUGH WEDNESDAY
229 AM CST MON NOV 21 2011
MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES FOR
TUESDAY.
SURFACE ANALYSIS THIS MORNING SHOWS HIGH PRESSURE CENTERED OVER
SOUTHERN ONTARIO WITH THE RIDGE AXIS EXTENDING SOUTHWEST INTO
NEBRASKA.
CLOUDS TODAY WILL BE PROBLEMATIC AS A STRATUS DECK THAT WAS OVER
THE REGION SUNDAY HAS YET TO CLEAR THE REGION. AS THE SURFACE HIGH
PULLS AWAY FROM THE AREA...THE LOW LEVEL WINDS WILL COME AROUND
MORE TO THE SOUTH. THIS SHOULD AT SOME POINT PUSH THIS STRATUS
DECK FARTHER TO THE NORTH BUT WHEN THIS OCCURS AND HOW FAR NORTH
THE CLOUDS GET IS QUESTIONABLE. FURTHER COMPLICATING
THINGS...ANOTHER STRATUS DECK RESIDES OVER MISSOURI...EXTREME
SOUTHERN IOWA INTO CENTRAL ILLINOIS. AS THE LOW LEVEL FLOW TURNS
TO THE SOUTH...THIS DECK COULD ALSO START MAKING A MOVE TOWARD THE
AREA. ALSO...SOME MID LEVEL MOISTURE AND CLOUDS ARE EXPECTED TO
STREAM IN FROM THE SOUTHWEST AND HAVE GONE WITH A MORE
PESSIMISTIC FORECAST HOLDING THE CLOUDS IN DURING THE MORNING
BEFORE SLOWLY DECREASING THEM THROUGH THE AFTERNOON.
A STRONG SHORT WAVE TROUGH CURRENTLY OFF THE SOUTHERN CALIFORNIA
COAST WILL EJECT OUT TO THE NORTHEAST STARTING TODAY. AS IT DOES...
IT WILL BE COMING INTO A STRONGLY CONFLUENT FLOW OVER THE OHIO
VALLEY AND NORTHEAST PART OF THE COUNTRY. THIS IS EXPECTED TO
CAUSE THE WAVE TO WEAKEN AND TO TAKE ON A POSITIVE TILT WITH A
WEAK SURFACE LOW TRACKING THROUGH THE OHIO VALLEY. THE ECMWF IS
THE STRONGEST WITH THE SURFACE WAVE BUT THE NEW 21.00Z RUN HAS
BACKED OFF SOME ON THE STRENGTH OF THE SYSTEM AND DOES NOT HAVE
THE PRECIPITATION NEARLY AS FAR NORTH. THE 21.03Z SREF MEAN IS BY
FAR THE WEAKEST WITH THIS SYSTEM AND WOULD SUGGEST THAT ONLY FAR
SOUTHERN GRANT COUNTY HAS ANY CHANCE OF GETTING SOME
PRECIPITATION. THE 21.00Z NAM AND GFS ARE IN THE MIDDLE OF THESE
WITH JUST SOME LIGHT PRECIPITATION AS FAR NORTH AS MAYBE ELKADER
TO RICHLAND CENTER. THERE IS NOT A LOT OF FORCING ON THE NORTH
SIDE OF THIS SYSTEM WITH THE NAM AND GFS SHOWING AT MOST 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ALONG WITH SOME
WEAK QG CONVERGENCE AND FRONTOGENESIS ABOVE 700 MB. WITH JUST SOME
WEAK FORCING...HAVE TRENDED THE FORECAST TOWARD THE WEAKER AND
MORE SOUTHERN SOLUTIONS AND CONFINED THE PRECIPITATION CHANCES TO
SOUTH OF A NEW HAMPTON TO ADAMS/FRIENDSHIP LINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
229 AM CST MON NOV 21 2011
STILL EXPECTING TO SEE A NICE WARM UP OCCURRING EARLY IN THE
PERIOD. HIGH PRESSURE WILL QUICKLY MOVE OFF TO THE EAST AND THE
RETURN LOW LEVEL FLOW WILL BRING WARMER AIR IN THE AREA. THE GFS
SUGGESTS 925MB TEMPERATURES WARMING TO AROUND 10C FOR THANKSGIVING
WITH A COLD FRONT EXPECTED TO COME ACROSS SOMETIME OVER THE
WEEKEND. THE MODELS HAVE DIVERGED ON THIS SYSTEM WITH THE ECMWF
BREAKING AWAY FROM THE CONSENSUS. THIS SYSTEM LOOKS TO BE A FULL
LONG WAVE TROUGH WITH EMBEDDED NORTHERN AND SOUTHERN STREAM SHORT
WAVE TROUGHS. THE ECMWF IS TRENDING TOWARD A STRONGER NORTHERN
STREAM SYSTEM THUS CAUSING THE LONG WAVE TROUGH TO TAKE ON A
POSITIVE TILT. IF THIS HAPPENS...THERE COULD BE LITTLE MOISTURE
RETURN AND NOT A LOT OF PRECIPITATION AS THE SYSTEM COMES THROUGH.
THE GFS AND 21.00Z GEM FOR NOW ARE HOLDING WITH THE IDEA OF THE
LONG WAVE TROUGH BEING STACKED WITH PRETTY MUCH EQUAL IN STRENGTH
NORTHERN AND SOUTHERN STREAM WAVES. THIS ALLOWS GULF MOISTURE TO
RETURN WITH SOME DECENT PRECIPITATION POSSIBLE. FOR NOW...HAVE
STAYED WITH THE NON ECMWF CONSENSUS SUGGESTING A PRETTY HIGH
PROBABILITY OF PRECIPITATION FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...TODAY AND TONIGHT
549 AM CST MON NOV 21 2011
THE CLOUD FORECAST THROUGH MID AFTERNOON IS PROBLEMATIC AS LOW
LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH AN INVERSION. THIS
MOISTURE HAS BEEN QUITE PREVALENT ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR. MEANWHILE SOME CLEARING HAS BEEN EVIDENT
IN THE SATELLITE FOG PRODUCT AND THE IN THE OBSERVATIONS ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. IN ADDITION...PATCHY AREAS
OF DENSE FOG HAVE DEVELOPED ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. KRST HAS BEEN IN THIS DENSE FOG SINCE 210852Z.
CURRENT THINKING IS THAT WITH THE LIGHT WINDS THAT THIS DENSE FOG
WILL LIKELY CONTINUE THERE THROUGH AT LEAST 21.15Z.
FOR LATE THIS MORNING AND EARLY AFTERNOON...THE MODELS CONTINUE TO
SUGGEST THAT THERE WILL BE SOME BRIEF CLEARING. HOWEVER THE ACTUAL
CONFIDENCE THAT THIS MAY ACTUALLY OCCUR IS LOW. AT THE MOMENT
CONCERNED ABOUT THE MVFR STRATUS SPREADING RAPIDLY NORTHWARD
ACROSS SOUTHERN IOWA. THE LATEST RUC SUGGESTED THAT THESE CLOUDS
WOULD NOT REACH KRST UNTIL 21.21Z AND KLSE AROUND 21.23Z...BUT
LIKE THE CURRENT CLOUDS THE MODELS ARE NOT PERFORMING THAT WELL.
WILL HAVE TO MONITOR THESE CLOUD TRENDS CLOSELY TODAY.
ONCE THESE CLOUDS MOVE BACK IN THEY WILL LIKELY LINGER THROUGH
TONIGHT. THERE MAY BE EVEN SOME IFR CEILINGS AFTER 22.09Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
229 AM CST MON NOV 21 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
308 PM EST MON NOV 21 2011
...AREAS OF DENSE FOG POSSIBLE TONIGHT...
.CURRENTLY...SFC HIGH PRES IS SITUATED OVER SE GA AND TEMPS ARE IN
THE LOWER 80S INLAND AREAS. HAVE REACHED A NEW RECORD HIGH AT ALMA
AND TEMP AT 2 PM WAS 82...PRIOR RECORD 81 IN 1991. BROAD INVERTED
SFC TROUGHING SW-NE LOCATED FROM FL KEYS TO CENTRAL FL AND INTO THE
WRN ATLC. ONLY FEW-SCT CU OVER THE AREA AT THIS TIME. WATER VAPOR
AND RUC FIELDS SHOW DRIER MID-UPPER LEVEL AIR RESIDING OVER NE FL
AND WITH WEAK DISTURBANCES IN PREVAILING WLY FLOW IN THE MID LEVELS
AFFECTING SE GA. FURTHER UPSTREAM...STRONG MID/UPPER TROUGH IS
ACROSS THE W CENTRAL CONUS.
.SHORT TERM...
TONIGHT...AS THE UPSTREAM TROUGH SHIFTS EWD...MEAN LAYER RIDGE WILL
CONT WORKING EWD RESULTING CONTD WARM ADVECTION PATTERN. LOW LEVEL
MOISTURE WILL INCREASE AS WILL LOW LEVEL WINDS. LATE NIGHT
DECOUPLING AND LIGHT SFC WINDS WILL PROMOTE FOG/STRATUS DEVELOPMENT
WITH AREAS OF FOG (SOME OF IT DENSE) MAINLY INLAND. LOWS AGAIN THE
MID-UPPER 50S AND NEAR 60 COAST.
TUE...APPEARS THAT PSEUDO WARM FRONT WILL LIFT NWD THROUGH OUR AREA
WITH ISOLD LIGHT PRECIP POSSIBLE INLAND ZONES. RAIN CHANCES FAIRLY
MINIMAL AT THIS TIME AT 20%. WOULD GO A COUPLE OF DEG ABOVE GUIDANCE
BUT WITH CLOUDINESS WILL KEEP HIGHS WITHIN A DEG OR SO. TUE
NIGHT...MODELS SHOW MID/UPPER TROUGH MOVING THROUGH THE TN VALLEY
WITH ASSOCD FRONT MOVING TO NEAR NRN GA TO THE LOWER MS VALLEY.
PRECIP CHANCES EXPECTED TO INCREASE GRADUALLY WITH HIGHER POPS
AROUND 30% OVER THE NW ZONES AFT MIDNIGHT. TEMPS WILL SLOWLY FALL TO
THE LOWER 60S. LOW STRATUS AND PATCHY FOG EXPECTED.
WED...COLD FRONT WILL SHIFT SEWD THROUGH OUR AREA WITH THE BEST
CHANCES OVER THE NRN ZONES CLOSER TO THE STRONGER Q-VECTOR
CONVERGENCE PER GFS SOLUTION. ATTM...HAVE RAISED POPS SLIGHTLY WITH
60% OVER INLAND SE GA ATTM AND CHANCE POPS ELSEWHERE. THUNDERSTORM
CHANCES STILL LOOK FAIR TO GOOD GIVEN THE WEAK INSTABILITY AVAILABLE
BUT FAIRLY STRONG DEEP LAYER SHEAR AROUND 40-55 KT. WON`T RULE OUT A
FEW STRONG STORMS GIVEN THE LLVL JET NEAR 35-40 KT JET N OF I-10.
EXPECT TEMPS TO RESPOND AHEAD OF FRONT WITH UPPER 70S TO NEAR 80.
WED NIGHT...FRONT WILL PRESS SWD WITH SOME ISOLD LINGERING SHOWERS
POSSIBLE EARLY EVENING BEFORE HIGH PRES BUILDS IN ON NW-N WINDS.
THU...HIGH PRES BUILDS N OF THE AREA AND MOSTLY SUNNY TO PARTLY
SUNNY SKIES. HIGHS EXPECTED IN UPPER 60S TO LOWER 70S WITH BREEZY
NELY WINDS EXPECTED COASTAL COUNTIES.
.LONG TERM...
PREVIOUS EXTDD DISCUSSION...FRI AND SAT SFC HIGH PRES BUILDS
OFFSHORE AND ENE OF THE AREA WITH BREEZY ONSHORE FLOW MODERATING
TEMPS WITH HIGHS IN THE 70S AND MINS FRI NIGHT IN THE 50S. PRECIP
CHANCES INCREASE FROM THE WEST SAT NIGHT AS THE NEXT FRONTAL SYSTEM
APPROACHES. MODELS DIVERGE ON FROPA TIMING SUN...AS WELL AS TRAILING
SFC HIGH PRESSURE POSITION WHICH WILL INFLUENCE COLD AIR ADVECTION
PATTERN AND PERSISTENCE LOCALLY. LEANED TOWARD THE GFS ENSEMBLE
WHICH SHOWS BROAD LOW PRESSURE AND LOW RAIN CHANCES IMPACTING THE
CWA SUN...TRAILED BY CLEARING MON NIGHT AND SFC HIGH PRESSURE
BUILDING OVER THE AREA FROM THE WNW MON. EXTENDED RANGE MODELS ARE
INSISTENT ON A DEEP LONG WAVE TROUGH ASSOCIATED WITH NEXT WEEKENDS
FROPA...AND THIS TRANSLATES INTO ANOTHER COOL DOWN EARLY NEXT WEEK.
FOR MON MORNING HAVE LOWS FALLING INTO THE LOW 40S INLAND...WITH
HIGHS MON IN THE LOW/MID 60S.
&&
.AVIATION...
CONDITIONS WILL ONCE AGAIN BE FAVORABLE FOR FOG TONIGHT. LIKE THE
PAST FEW NIGHTS IT WILL LIKELY BE MORE OF A PATCHY DENSE FOG
EVENT...WHICH WILL MAKE IT DIFFICULT TO CAPTURE IN TAFS. WILL SHOW
A TREND TO IFR CONDITIONS BY LATE TONIGHT AT ALL BUT THE SSI
TERMINAL. OTHERWISE...VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...
SURFACE RIDGE OVER THE AREA WILL KEEP LIGHT EASTERLY FLOW IN PLACE
THROUGH TUESDAY MORNING. THE RIDGE WILL SHIFT SOUTH OF THE AREA BY
TUESDAY EVENING AND WINDS WILL TURN TO THE SOUTH AND INCREASE TO
15 TO 20 KNOTS WITH SEAS BUILDING TO 4 TO 6 FEET. WINDS WILL
CONTINUE TO VEER ON WEDNESDAY AS A COLD FRONT CLOSES IN ON THE
AREA. THE FRONT IS PROGGED TO CLEAR THE AREA WEDNESDAY EVENING
WITH WINDS TURNING TO THE NORTHWEST AND INCREASING TO 20 TO 25
KNOTS. SCA HEADLINES WILL BE NEEDED BEGINNING WEDNESDAY NIGHT.
SEAS WILL ALSO BUILD...REACHING 6 TO 8 FEET BY THURSDAY NIGHT.
HIGH SEAS WILL LINGER INTO THE WEEKEND.
RIP CURRENTS: MODERATE RISK THROUGH TUESDAY DUE TO LINGERING
EASTERLY SWELLS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 56 81 62 76 / 0 20 30 60
SSI 60 74 63 75 / 10 10 30 50
JAX 57 81 61 79 / 10 20 20 50
SGJ 63 79 65 80 / 10 10 20 50
GNV 57 81 60 79 / 10 20 20 50
OCF 60 82 60 80 / 10 20 20 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1249 PM EST MON NOV 21 2011
.SYNOPSIS...
A PRESSURE RIDGE WILL BE CENTERED EAST AND SOUTH OF THE FORECAST
AREA THROUGH TUESDAY. A COLD FRONT APPROACHING FROM THE WEST WILL
MOVE THROUGH THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ZONAL FLOW OVER REGION TODAY. RUC MODEL SHOWS A WEAK SHORT WAVE
EXITING TO THE EAST BY LATE MORNING THEN NVA EARLY THIS AFTERNOON.
HOWEVER...ANOTHER WEAK RIPPLE MOVES MAINLY IN THE NORTHERN PART OF
THE AREA LATER THIS AFTERNOON. SO WILL KEEP A 20 PERCENT CHANCE OF
SHOWERS NORTH PART THIS AFTERNOON. WEAK ISENTROPIC LIFT THROUGHOUT
TODAY SHOULD HELP MAINTAIN SOME CLOUDINESS. WE WILL REMAIN IN THE
WARM AIR MASS WITH A PRESSURE RIDGE EAST AND SOUTH OF THE FORECAST
AREA. THE TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
THE NAM AND GFS KEEP A WARM FRONT AND ASSOCIATED DEEPER MOISTURE
NORTH OF THE FORECAST AREA THROUGH TUESDAY. A COLD FRONT
APPROACHING FROM THE WEST TUESDAY NIGHT SHOULD MOVE THROUGH THE
FORECAST AREA WEDNESDAY. NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
WILL LIKELY OCCUR MAINLY ASSOCIATED WITH THE H85 JET AHEAD OF THE
FRONT. USED THE HIGHER NAM MOS POPS. THE NAM AND GFS INDICATE H85
WINDS OF 35 TO 40 KNOTS. SEVERE THUNDERSTORMS MAY OCCUR BECAUSE OF
THE STRONG SHEAR. THE MODELS SHOW THE JET AND ASSOCIATED MOISTURE
SHIFTING EAST OF THE FORECAST AREA BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE WEDNESDAY
NIGHT THROUGH SATURDAY. THE GFS SHOWS THE PRESSURE RIDGE EXTENDING
THROUGH THE FORECAST AREA FRIDAY. THE GFS ENSEMBLE MEANS INDICATE
THE COLDEST TEMPERATURES FRIDAY MORNING AND THIS APPEARS REASONABLE
BECAUSE OF THE STRONGEST RADIATIONAL COOLING. THE GFS SHOWS A STRONG
COLD FRONT MOVING INTO THE AREA SUNDAY. THE GFS ENSEMBLE MEAN
POPS SUPPORT POPS AROUND 30 PERCENT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK HIGH PRESSURE REMAINS OVER THE AREA THIS AFTERNOON WITH WSW
FLOW ALOFT. EXPECT SOME WEAK RIPPLES IN THE UPPER FLOW TODAY WHICH
MAY TRIGGER A FEW SHOWERS ACROSS THE AREA DURING THE AFTERNOON
HOURS...MAINLY ACROSS THE NORTHERN CWA INTO NC. VFR CONDITIONS THIS
AFTERNOON...BUT GUIDANCE INDICATES DETERIORATING CONDITIONS
OVERNIGHT/TUESDAY MORNING. MODELS MAINTAIN THE FOG THREAT AFTER
22/00Z...SO HAVE INCLUDED MVFR FOG AT ALL TAF SITES FROM ABOUT
22/04Z ONWARD. WITH GUIDANCE SO PESSIMISTIC AND BUFKIT SHOWING
PLENTY OF LOW LEVEL MOISTURE/LIGHT WINDS...EXPECT A PERIOD OF
IFR/LIFR THROUGH 14Z. EXPECT VFR CONDITIONS TO RETURN AFTER 14Z.
EXTENDED AVIATION OUTLOOK...MVFR TO IFR CIGS/VSBYS POSSIBLE
WEDNESDAY MORNING ASSOCIATED WITH AN APPROACHING FRONTAL SYSTEM
FROM THE NORTHWEST.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
304 PM EST MON NOV 21 2011
.SHORT TERM...
TONIGHT THROUGH TUESDAY NIGHT...
WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING SHORT WAVE
ENERGY EJECTING OUT OF THE BASE OF UPPER TROUGH ALONG SW US/MEX
BORDER THIS AFTERNOON. THIS WILL QUICKLY MOVE THROUGH THE MORE
PROGRESSIVE ZONAL FLOW EAST OF THE MISSISSIPPI AND RESULT IN SFC LOW
DEEPENING AND MOVING ALONG THE OHIO RIVER VALLEY ON TUESDAY.
FORECAST AREA WILL BE IN THE OVERRUNNING PRECIP NORTH OF THIS SYSTEM
MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS. PRONOUNCED
BACKING OF THE WINDS ALONG THE 300K THETA SFC WILL LEAD TO ENHANCED
ISENTROPIC ASCENT OVER THE AREA TUESDAY MORNING...BUT WILL TAKE SOME
TIME TO OVERCOME MID LEVEL DRYING...SO HAVE BACKED DOWN A BIT ON
POPS IN THE 12-18Z TIMEFRAME OVER THE NORTHERN HALF OF THE CWA.
ENTIRE COLUMN WILL THEN QUICKLY SATURATE EARLY TUESDAY AFTERNOON
LENDING CREDENCE TO A DEFINITE RAIN EVENT OVER ALL OF THE FORECAST
AREA TUESDAY AFTERNOON/EVENING. WHILE AXIS OF HEAVIEST PRECIP
EXPECTED TO BE SOUTH OF THE FORECAST AREA...SOUTHERN CWA COULD STILL
SEE IN EXCESS OF ONE INCH OF RAIN. SYSTEM TO EXIT THE AREA TUESDAY
NITE WITH JUST CHANCE POPS LEFT IN SE CWA AFTER MIDNIGHT. SOUTHERLY
TRACK OF SFC LOW WILL KEEP FCST AREA IN COOL EASTERLY FLOW AT LOW
LEVELS WHICH WILL HAMPER MIXING DOWN WAA ALOFT...HAVE CUT HIGHS TUE
FROM CURRENT FCST MORE TOWARD LATEST MOS GUIDANCE TO BETTER REFLECT
THIS THINKING.&&
.LONG TERM...
RIDGING SFC AND ALOFT TO BLD IN ACRS THE CWA TO START THE PD ON WED
BEHIND DEPARTING SHRT TERM SYS AND APCHG DEEP LYRD TROUGH CROSSING
THE ROCKIES FRI. BIGGEST CHG WAS TO BUMP TEMPS CONSIDERABLY THU-SAT
AND AGAINST PREVAILING ALLBLEND PROCEDURE WHICH AGAIN TDA WAS BIASED
WET AND COOL.
OTHERWISE PROBS ABOUND W/POTENTIAL PHASING ISSUED RELEGATED TO SPLIT
STREAM FLW ACRS THE WRN US LT WEEK AND NXT WEEKEND. GREATER
CONTINUITY LIES W/OP GFS AND ECM/GFS ENSEMBLES AND HAVE GENERALLY
FOLLOWED SUGGESTION OF MODEL CONSENSUS THIS AFTN ESP IN LIGHT OF
MORE AGREEABLE SLOWING TREND SEEN IN SUBSEQUENT MODEL INTERATIONS
SINCE YDA AND DISCUSSED YDA. THUS DROPPED FRI NIGHT PCPN MENTION
ALTOGETHER AND NOTCHED W-E GRADIENT FURTHER SAT. REMAINDER ON TRACK
ATTM TIED TO PROGGED DEEP MID MS VALLEY CUTOFF LT NXT WEEKEND YET
STILL HIGHLY UNCERTAIN W/CONSIDERABLE MODEL SPREAD ALOFT NOT TO
MENTION VARIOUS PLACEMENT VAGARIES. THUS WILL HOLD SHORT OF ANY
PERCEIVED LIKELY MENTION AT THIS TIME IN LIGHT OF THE UNCERTAINTY.
&&
.AVIATION...
AMPLE BOUNDARY LAYER/LOW LEVEL MOISTURE REMAINING TRAPPED UNDER
850MB INVERSION AND AS A RESULT MVFR CIGS HAVE PERSISTED AT BOTH TAF
SITES INTO THIS AFTERNOON. VISIBLE SATELLITE SHOWING NORTHERN EDGE
OF LOW CLOUDS ALONG IN/MI BORDER...STILL HOLDING OUT SOME HOPE FOR
SCATTERING OUT AT KSBN LATER IN THE AFTERNOON BUT PLAN TO JUST KEEP
KFWA LOCKED IN REMAINDER OF THE TAF PERIOD. RAIN EXPECTED TO MOVE IN
TUESDAY FROM SOUTH TO NORTH. WILL INTRODUCE TO KFWA TOWARD END OF
THIS TAF CYCLE BUT HOLD OFF ON KSBN TILL NEXT ISSUANCE. SFC LOW TO
TRACK SOUTH OF BOTH TAF SITES KEEPING EASTERLY FLOW IN PLACE THROUGH
THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LOGSDON
LONG TERM...T
AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1056 AM CST MON NOV 21 2011
.UPDATE...
12Z UA ANALYSIS HAS A MESO HIGH AT 850MB OVER THE CWFA WHICH
HELPED TO BREAK UP THE CLOUDS ACROSS THE AREA. SATELLITE TRENDS
SHOW THE LOW CLOUDS GENERALLY ALONG THE EDGES OF THE WEST AND
SOUTHERN PARTS OF THE CWFA WITH HIGH LEVEL CI/CS MOVING IN FROM
THE SOUTH AND WEST.
RUC TRENDS SUGGEST FILTERED SUN DEVELOPING THIS AFTERNOON AS THE
CS/CI SHIELD BUILDS INTO THE AREA. THE ADDITIONAL SUN IS ALSO
PUSHING TEMPERATURES CLOSER TO THE MAX TEMPERATURES AND
ADJUSTMENTS HAVE BEEN MADE AS WELL. THOSE AREAS THAT ALREADY HAVE
THE LOW CLOUDS PRESENT WILL PROBABLY NOT SEE MUCH IN THE WAY OF
ADDITIONAL RISE TODAY.
AN UPDATE TO THE FCST REFLECTING ALL THIS HAS BEEN SENT.
..08..
&&
.AVIATION...
A MESO HIGH IS CREATING WEAK DOWNWARD MOTION THAT IS PREVENTING
THE MVFR CIGS FM MOVG INTO EASTERN IOWA/NORTHERN ILLINOIS.
SATELLITE ALONG WITH RUC TRENDS INDICATE HIGH LEVEL CLOUDS WILL
OVERSPREAD THE AREA THROUGH 20Z/21. RUC IS SUGGESTING A POSSIBLE
SCT-BKN CLOUD DECK DVLPG AT THE 6-9KFT AGL AFT 18Z/21. IF THE RUC
TRENDS ARE CORRECT...MVFR CIGS OF 2-3KFT AGL DVLPG AT KBRL AFT
00Z/22. KCID/KDBQ/KMLI MAY SEE MVFR CIGS OF 2-3KFT AGL AFT 06Z/22.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
312 PM CST MON NOV 21 2011
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS THE UPPER LEVEL LOW MOVING ACROSS THE
FOUR CORNERS REGION CAUSING SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS WESTERN OK AND THE TX PANHANDLE. SURFACE OBS SHOW RIDGING
STILL IN PLACE ACROSS THE UPPER MIDWEST AND NOSING INTO NORTHEAST
KS.
FOR TONIGHT AND TUESDAY...PRECIPITATION IS EXPECTED TO BECOME MORE
WIDESPREAD AS THE UPPER LEVEL WAVE MOVES CLOSER AND UPPER DIFFLUENCE
INCREASES ALONG WITH INCREASING MOISTURE ADVECTION. THE MAIN CONCERN
IS POTENTIAL FOR A BRIEF PERIOD OF FREEZING RAIN ACROSS FAR NORTH
CENTRAL KS. MOS GUIDANCE WANTS TO TAKE LOWS BELOW FREEZING...HOWEVER
FORECAST SOUNDINGS FROM THE NAM AND GFS BOTH SHOW SFC TEMPS
REMAINING IN THE MIDDLE AND UPPER 30S. WITH OVERCAST SKIES
ANTICIPATED TO PERSIST AND MODELS SHOWING WEAK TEMP ADVECTION IF ANY
AT ALL...HAVE FAVORED THE MORE MILD TEMP FORECAST FROM THE FORECAST
SOUNDINGS. THEREFORE HAVE CONTINUED WITH A FORECAST OF ALL RAIN. MID
LEVEL LAPSE RATES CONTINUE TO SUGGEST SOME ISOLATED THUNDER WITH THE
PRECIP AS WELL. RAIN SHOULD COME TO AN END DURING THE DAY TUESDAY AS
THE UPPER LEVEL WAVE MOVES EAST AND SUBSIDENCE INCREASES. HIGHS ARE
FORECAST TO RANGE FROM THE UPPER 40S IN THE EAST WITH CLOUDS MOST OF
THE DAY AND LOWER 50S WEST WHERE SOME SUNSHINE SHOULD BREAK OUT BY
THE AFTERNOON.
WOLTERS
TUESDAY NIGHT THROUGH THANKSGIVING DAY...
MODELS CONTINUE IN EXCELLENT AGREEMENT THAT THE INITIAL SHORTWAVE
TROUGH WILL MOVE RAPIDLY EASTWARD INTO THE OH RIVER VALLEY TUESDAY
EVENING AS UPPER LEVEL RIDGING INCREASES ACROSS THE HIGH PLAINS.
THIS WILL ALLOW FOR WARM AIR ADVECTION AT 850MB TO BEGIN ACROSS THE
WESTERN COUNTY WARNING AREA (CWA) IN THE 06Z-12Z WED. TIMEFRAME THEN
EASTWARD DURING THE DAY WEDNESDAY ACROSS THE REMAINDER OF THE CWA.
HOWEVER...SINCE TUESDAY NIGHT SFC WINDS WILL BE FAIRLY LIGHT AND
SKIES CLEAR...SHOULD SEE MORNING LOWS IN THE UPPER 20S TO LOWER 30S.
ON THE OTHER HAND...THE CONTINUED WARM AIR ADVECTION AND BETTER
MIXING DURING THE DAY WITH ABUNDANT SUNSHINE SHOULD PUSH HIGHS INTO
THE MIDDLE 50S FAR NORTHEAST TO THE UPPER 50S TO LOWER 60S ELSEWHERE.
THE UPPER LEVEL RIDGE WILL THEN PUSH EASTWARD ACROSS THE CENTRAL
PLAINS WEDNESDAY NIGHT. THE UPPER FLOW OVER THE CWA WILL THEN BECOME
SOUTHWESTERLY ON THANKSGIVING DAY AS THE NEXT SHORTWAVE TROUGH
APPROACHES THE SOUTHERN ROCKIES. THIS WILL KEEP UNSEASONABLY MILD
AIR IN PLACE ACROSS THE AREA WEDNESDAY THROUGH THANKSGIVING DAY.
AFTER LOWS IN THE UPPER 30S TO LOWER 40S...GUSTY SOUTH WINDS AND
MOSTLY SUNNY SKIES WILL ALLOW FOR HIGHS ON THANKSGIVING DAY TO TOP
OUT IN THE LOW TO MIDDLE 60S. 63
EXTENDED FORECAST (THURSDAY NIGHT THROUGH MONDAY)
FRIDAY AN UPPER LEVEL TROUGH WILL MOVE OUT OF THE ROCKY MOUNTAINS
INTO THE CENTRAL PLAINS BRINGING A SURFACE COLD FRONT THROUGH KANSAS
ON FRIDAY. THE LATEST 12Z ECMWF HAS NOW TRENDED TOWARDS THE GFS WITH
A MORE PROGRESSIVE SYSTEM MOVING THROUGH THE CENTRAL PLAINS. THERE
WILL BE ENOUGH LIFT AND MOISTURE RETURN AHEAD OF THE FRONT FOR
SHOWERS FRIDAY AFTERNOON INTO SATURDAY MORNING. MODELS ARE SHOWING A
MINIMAL AMOUNT OF ELEVATED INSTABILITY AHEAD OF THE FRONT AND A FEW
ISOLATED THUNDERSTORMS COULD BE POSSIBLE FRIDAY AFTERNOON. THE ECMWF
IS THE SLOWEST OF ALL THE MODELS BUT STILL BRINGS THE COLD FRONT
TROUGH THE CWA BY EARLY MONDAY MORNING.
MODELS THEN CLOSE OFF AN UPPER LEVEL LOW OVER THE MID MISSISSIPPI
RIVER VALLEY LATE NEXT WEEKEND AND EARLY NEXT WEEK. THIS WILL ALLOW
FOR COLD AIR ADVECTION TO CONTINUE OVER THE CENTRAL PLAINS ON THE
WESTERN SIDE OF THE UPPER LEVEL LOW. MODELS ARE INDICATING 850MB
TEMPERATURES OF -7 TO -9 CELSIUS ON SUNDAY AND INTO MONDAY.
NORTHWEST WINDS WILL ADVECT COLD AIR IN ALL THE WAY FROM SOUTHERN
CANADA DOWN INTO THE WESTERN GULF OF MEXICO. THEREFORE...DECIDED TO
DROP TEMPERATURES A FEW DEGREES BELOW GUIDANCE AFTER THE FRONT
PASSAGE FOR LATE NEXT WEEKEND INTO EARLY NEXT WEEK.
ANDERSON
&&
.AVIATION...
LATEST RUC AND NAM RH PROGS ARE TRYING TO KEEP THE MVFR CIGS IN
THROUGH THE AFTERNOON. DO NOT SEE ANY SUBSIDENCE MOVING IN THIS
AFTERNOON AND AREA OBS ARE ALL BELOW 3 KFT. THEREFORE WILL GO WITH
PERSISTENCE REGARDING THE CIGS THIS AFTERNOON. THINK THAT IF
ANYTHING THE CIGS COULD GRADUALLY IMPROVE AS THE BOUNDARY LAYER
DEEPENS FROM LIMITED DIURNAL HEATING. PRECIP AND IFR CIGS LOOK TO
MOVE INTO THE TERMINALS LATE TONIGHT. IF MODEL PROGS OF PRECIP
INTENSITY ARE CORRECT...VSBY COULD ALSO BECOME IFR WITH MODERATE OR
BRIEF HEAVY RAINFALL. AT THIS POINT THINK TEMPS WILL REMAIN IN THE
MID 30S OVERNIGHT...KEEPING PRECIP IN LIQUID FORM.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
1156 AM CST MON NOV 21 2011
.AVIATION...
FOR THE 18Z TAF ISSUANCE......LOW CLOUDS SLOW TO ERODE EARLIER
THIS MORNING AS HIGH CLOUDS CONTINUE TO THICKEN ACROSS THE AREA.
DO EXPECTED IFR/MVFR CONDITIONS TO GIVE WAY TO VFR CONDITIONS
WITHIN THE NEXT HOUR...HOWEVER AS LOW LEVEL MOISTURE SPREADS INTO
SOUTHWEST KANSAS THIS EVENING AHEAD OF A 400MB PRESSURE ANOMALY DO
ANTICIPATE A RETURN OF AT LEAST MVFR CIGS BY EARLY EVENING. IN
ADDITION TO THE LOWER CIGS EARLY TONIGHT THERE WILL BE INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS....ESPECIALLY AT DDC AND
HYS. BASED ON THE LOCATION OF THE 300MB JET AND 400MB PV ANOMALY WILL
INTRODUCE A PREVAILING GROUP OF PRECIPITATION AT DDC AND HYS EARLY
TONIGHT. AT GCK THE PROBABILITY WILL BE LESS BUT WILL INSERT A
PROB30 GROUP HERE. WINDS OVER THE NEXT 6 TO 9HOURS WILL BE
SOUTHEAST AT 10KTS OR LESS THROUGH EARLY TONIGHT.
AFTER MIDNIGHT THESE SOUTH/SOUTHEAST WINDS WILL BECOME NORTHWEST AS
PRECIPITATION BEGINS TO END. THE LOWER LEVELS BETWEEN 06Z AND 12Z
WILL SATURATE AND IFR/LIFR CIGS/VSBYS ARE EXPECTED TO DEVELOP. WILL
THEREFORE INTRODUCE IFR CONDITIONS AT ALL TAF SITES BY 09Z. -RB
&&
PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1126 AM CST MON NOV 21 2011
.AVIATION...
FOR THE 18Z TAF ISSUANCE......LOW CLOUDS SLOW TO ERODE EARLIER
THIS MORNING AS HIGH CLOUDS CONTINUE TO THICKEN ACROSS THE AREA.
DO EXPECTED IFR/MVFR CONDITIONS TO GIVE WAY TO VFR CONDITIONS
WITHIN THE NEXT HOUR...HOWEVER AS LOW LEVEL MOISTURE SPREADS INTO
SOUTHWEST KANSAS THIS EVENING AHEAD OF A 400MB PRESSURE ANOMALY DO
ANTICIPATE A RETURN OF AT LEAST MVFR CIGS BY EARLY EVENING. IN
ADDITION TO THE LOWER CIGS EARLY TONIGHT THERE WILL BE INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS....ESPECIALLY AT DDC AND
HYS. BASED ON THE LOCATION OF THE 300MB JET AND 400MB PV ANOMALY.
AS A RESULT WILL INTRODUCE A PREVAILING GROUP OF PRECIPITATION AT
DDC AND HYS EARLY TONIGHT. AT GCK THE PROBABILITY WILL BE LESS BUT
WILL INSERT A PROB30 GROUP HERE. WINDS OVER THE NEXT 6 TO 9HOURS
WILL BE SOUTHEAST AT 10KTS OR LESS THROUGH EARLY TONIGHT.
AFTER MIDNIGHT THESE SOUTH/SOUTHEAST WINDS WILL BECOME NORTHWEST AS
PRECIPITATION BEGINS TO END. THE LOWER LEVELS BETWEEN 06Z AND 12Z
WILL SATURATE AND IFR/LIFR CIGS/VSBYS ARE EXPECTED TO DEVELOP. WILL
THEREFORE INTRODUCE IFR CONDITIONS AT ALL TAF SITES BY 09Z. -RB
&&
PREV DISCUSSION... /ISSUED 311 AM CST MON NOV 21 2011/
SYNOPSIS...
WV LOOP AND RUC ANALYSIS AS OF 21/08Z SHOWED AN UPPER LOW CONTINUING
TO MOVE EAST ACROSS SOUTHERN CALIFORNIA/NORTHERN BAJA CALIFORNIA. A
SUBTROPICAL JET STREAK WAS NOTED AHEAD OF THIS UPPER LOW PROVIDING
ENHANCEMENT IN MID AND HIGH LEVEL CLOUD COVER ACROSS MUCH OF NEW
MEXICO. ANOTHER EXITING JET STREAK WITHIN THIS SOUTHERN BRANCH WAS
LOCATED ACROSS THE MID MISSISSIPPI VALLEY REGION WHICH WAS
RESPONSIBLE FOR WIDESPREAD DEVELOPMENT OF THUNDERSTORMS OVER
ARKANSAS AND POINTS EAST INTO THE MEMPHIS AND PADUCAH AREAS. AT THE
SURFACE...THE COLD ARCTIC HIGH THAT WAS RESPONSIBLE FOR THE COLDEST
AIRMASS OF THE SEASON SO FAR WAS MODIFYING FAIRLY SIGNIFICANTLY WITH
PERSISTENT DOWNSLOPE FLOW ACROSS THE NORTHERN HIGH PLAINS. 850MB
ANALYSIS SHOWED IMPRESSIVE WARMING IN AREAS LIKE RAPID CITY SD,
BISMARCK ND, AND GLASGOW MT WHERE 850MB TEMPERATURES WARMED 13 TO 16
DEGC OVER THE PAST 24 HOURS. THE FRONT AT THE SURFACE AS OF 08Z WAS
FROM ROUGHLY ODESSA TO JUNCTION TO TYLER IN TEXAS. -UMSCHEID
DISCUSSION...
DAYS 1-2 /TODAY THROUGH TUESDAY NIGHT...
SENSIBLE WEATHER CONCERNS AND CHALLENGES:
CHALLENGES IN THE FORECAST ARE HOW MUCH PRECIPITATION WILL FALL
ACROSS THE EASTERN FORECAST AREA...AND HOW FAR WEST ANY MEASURABLE
PRECIPITATION WILL BE. THIS STORM SYSTEM WILL NOT BE A BIG
PRECIPITATION PRODUCER FOR MUCH OF THE DDC FA.
TODAY:
BY MID TO LATE IN THIS PERIOD...THE UPPER LOW MENTIONED ABOVE IN THE
SYNOPSIS WILL HAVE REACHED SOUTHERN NEW MEXICO IN A WEAKER STATE.
THE UPPER LOW IS GOING TO BE ENTERING A STATICALLY STABLE LOWER
TROPOSPHERE ACROSS MUCH OF THE CENTRAL PLAINS...WITH THE BEST LOW
LEVEL FORCING/FRONTOGENESIS FOR ASCENT WELL TO THE SOUTHEAST OF THE
DDC FORECAST AREA. THE FORMER ARCTIC HIGH WILL CONTINUE TO WEAKEN
WITH A WEAK SURFACE LOW TRYING TO FORM NEAR TUCUMCARI BY THE END OF
THIS PERIOD. SOUTHERLY WINDS AT 850MB ABOVE THE SHALLOW COLD
AIRMASS WILL ADVECT MOISTURE NORTH TOWARD THE SOUTHERN DDC FA BY THE
END OF THE PERIOD...AND AM EXPECTING SOME LIGHT SHOWERY
PRECIPITATION TO BEGIN REACHING AREAS LIKE MEADE, ASHLAND,
COLDWATER, AND KIOWA BY 00Z. A MUCH LARGER AREA OF CONCENTRATED
THUNDERSTORM ACTIVITY WILL BE ALONG THE SURFACE FRONT ACROSS THE RED
RIVER VALLEY. THIS IS WHERE THE 500MB JET WILL BE PUSHING TOWARD AS
WELL.
TONIGHT:
THE MAIN PRECIPITATION EVENT WILL OCCUR DURING THIS PERIOD...MAINLY
IN THE 03 TO 09Z TIME FRAME...AND PRIMARILY EAST OF A MEADE TO DODGE
CITY TO HAYS LINE. WEST OF THIS LINE...THERE JUST WILL NOT BE THE
FORCING AND ADVECTION OF MOISTURE TO SUPPORT ACCUMULATING
PRECIPITATION OF CONSEQUENCE. THEREFORE...POPS ARE VERY LOW (BELOW
20 PERCENT) WEST OF THIS LINE. THE LARGE AREA OF THUNDERSTORMS OVER
OKLAHOMA WILL LIKELY RESULT IN A REDISTRIBUTION OF MID LEVEL
POTENTIAL VORTICITY AND UPPER TROPOSPHERIC JET STREAK DUE TO THE
AMOUNT OF LATENT HEAT BEING RELEASED...SO THIS WILL FURTHER
EXACERBATE THE LACKLUSTER FORCING FOR MEASURABLE
PRECIPITATION...EVEN IN THE EASTERN FORECAST AREA. WILL MAINTAIN 70
TO 80 POPS OVER THE FAR SOUTHEAST (PRATT AND BARBER COUNTIES, FOR
EXAMPLE) WITH FORECAST PRECIPITATION AMOUNTS OF 0.2 TO 0.35 INCHES
IN PRATT AND BARBER COUNTIES. TEMPERATURES ARE EXPECTED TO HOLD
STEADY IN THE UPPER 30S FOR THE DURATION OF THE PRECIP EVENT.
TUESDAY AND TUESDAY NIGHT:
IT WILL BE A RAPID TRANSITION TO DOWNSLOPE WARMING ON TUESDAY IN THE
WAKE OF THE MONDAY NIGHT STORM SYSTEM. RIDGING IN THE MID AND UPPER
LEVELS WILL BUILD OVER THE ROCKIES AS ANOTHER PACIFIC JET ENTERS THE
PACIFIC NORTHWEST REGION. THIS WILL LEAD TO ENHANCED LEE TROUGHING
BY TUESDAY NIGHT ACROSS THE NORTHERN HIGH PLAINS...BUT ACROSS
SOUTHWEST KANSAS DURING THE DAY TUESDAY...WILL SEE A REMNANT 850MB
GRADIENT FROM SOUTHWEST TO NORTHEAST WHICH WILL SUPPORT SURFACE
WINDS IN THE 12-15 KNOT RANGE AND A WARM UP TO THE UPPER 50S TO
LOWER 60S OVER MUCH OF THE AREA WITH THE SLIGHT DOWNSLOPE
COMPONENT. TUESDAY NIGHT WILL BE CLEAR WITH WINDS WEAKENING TO 6
KNOTS OR LESS PROVIDING A COOL NIGHT. HAVE LOWERED THE MINS A FEW
DEGREES ACROSS THE ENTIRE FORECAST AREA INTO THE UPPER 20S TO NEAR
30. -UMSCHEID
DAYS 3-7 /WEDNESDAY THROUGH SUNDAY NIGHT/...
MODELS CONTINUE THE GENERAL IDEA OF DEVELOPING WEAK MID LEVEL
RIDGING ON WEDNESDAY. THIS RIDGING GETS BROKEN DOWN RATHER QUICKLY
HOWEVER AS ANOTHER SYSTEM MOVES INTO THE WESTERN CONUS ON THURSDAY.
THE DETAILS OF THE SYNOPTIC PATTERN OF THAT SYSTEM WILL HAVE
RAMIFICATIONS ON OUR SENSIBLE WEATHER HEADING INTO THE WEEKEND.
ON WEDNESDAY THE UPPER RIDGE WILL BE DEVELOPING WITH 500 MB HEIGHTS
ON THE ORDER OF 576DM TO 580DM OVER WESTERN KS. AS SURFACE
ANTICYCLONE WILL BE SLOWLY RETREATING INTO THE SE US, AND WEAK LEE
TROUGHING DEVELOPING OVER THE HIGH PLAINS OF COLORADO. THEREFORE
SOUTHWEST FLOW WITH A SLIGHT DOWNSLOPE COMPONENT WILL BE EXPECTED.
ADD TO THIS FULL INSOLATION IN A DRY AIRMASS AND TEMPERATURES WILL
EASILY REACH THE 60S ACROSS THE ENTIRE FORECAST AREA. IT IS
CONCEIVABLE THAT EVEN 70 DEGREES MIGHT BE ACHIEVED IS THE MIXING IS
STRONGER THAN EXPECTED, AND THE MOST FAVORABLE AREA MIGHT BE NEAR
THE OKLAHOMA LINE AND RED HILLS WHICH SEEMS TO BE CAPTURED IN OUR
GFSMOS GRIDS THIS MORNING. WIND SPEEDS ARE GOING TO BE DETERMINED BY
THE GRADIENT WHICH ONLY APPEARS TO BE AROUND 5 MB. WE LIKE THE
STRONGER GFS MOS WINDS OVER ANY OF THE MODELS WHICH SHOULD PRODUCE
15-18KT WINDS GUSTING TO 30 MPH AT TIMES IN THE AFTERNOON.
THURSDAY SHOULD BE SIMILARLY WARM, WITH A SIMILAR (OR SLIGHTLY EVEN
STRONGER) WIND FIELD AS LEE TROUGHING CONTINUES. THE PATTERN ALSO
STILL SUGGEST MILD OVERNIGHT TEMPERATURES THURSDAY MORNING. THE FACT
THAT THE WINDS MIGHT BE STRONGER IS A RESULT OF AN INCREASING
SOUTHWEST FLOW DUE TO AN ADVANCING UPPER TROUGH THROUGH THE WESTERN
STATES. JUST HOW THE JETS ARE ORIENTED HEADING ONTO FRIDAY AND
SATURDAY WILL DETERMINE HOW STRONG THE COLD FRONT MAY BE LATE
FRIDAY. THE GFS AND CANADIAN AREA MORE PROGRESSIVE WITH A STRONGER
COLD FRONT AND STRONGER NORTHWEST SURFACE WINDS HEADING INTO LATE
FRIDAY AND SATURDAY, WHEREAS THE ECMWF ALLOWS A CUTOFF LOW OVER NEW
MEXICO AND NOT AS BUCKLED OF AN UPPER JET STRUCTURE. THIS ECMWF
WOULD SUPPORT NOT QUITE AS FAST OF A FRONTAL PASSAGE, AND PROBABLY
NOT AS COLD EITHER. THEREFORE, THE MORE GRADUAL/MODERATE COOLDOWN OF
THE CURRENT ALLBLEND FORECAST SEEMS APPROPRIATE FOR NOW. WE CAN THEN
SEE IF THE MODELS CONVERGE IN THE COMING RUNS. IF THE ECMWF
CONVERGES TOWARD THE GFS AND CANADIAN SOLUTIONS, WE COULD SEE MUCH
COLDER TEMPERATURES AS EASTERLY AS FRIDAY,A AND DEFINITELY ON
SATURDAY. -RUSSELL
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 33 58 29 / 20 30 10 0
GCK 47 31 59 28 / 10 10 10 0
EHA 49 32 59 31 / 10 10 0 0
LBL 46 33 60 30 / 20 20 0 0
HYS 45 31 57 27 / 10 40 10 0
P28 44 35 57 30 / 40 70 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1114 AM CST MON NOV 21 2011
...AVIATION UPDATE...
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
LATEST RUC AND NAM RH PROGS ARE TRYING TO KEEP THE MVFR CIGS IN
THROUGH THE AFTERNOON. DO NOT SEE ANY SUBSIDENCE MOVING IN THIS
AFTERNOON AND AREA OBS ARE ALL BELOW 3 KFT. THEREFORE WILL GO WITH
PERSISTENCE REGARDING THE CIGS THIS AFTERNOON. THINK THAT IF
ANYTHING THE CIGS COULD GRADUALLY IMPROVE AS THE BOUNDARY LAYER
DEEPENS FROM LIMITED DIURNAL HEATING. PRECIP AND IFR CIGS LOOK TO
MOVE INTO THE TERMINALS LATE TONIGHT. IF MODEL PROGS OF PRECIP
INTENSITY ARE CORRECT...VSBY COULD ALSO BECOME IFR WITH MODERATE OR
BRIEF HEAVY RAINFALL. AT THIS POINT THINK TEMPS WILL REMAIN IN THE
MID 30S OVERNIGHT...KEEPING PRECIP IN LIQUID FORM.
WOLTERS
&&
.PREV DISCUSSION... /352 AM CST MON NOV 21 2011/
LOW STRATUS HAS WORKED ITS WAY NORTHWARD THROUGH THE EARLY MORNING
HOURS TODAY INTO NORTH CENTRAL KANSAS AND SOUTHEAST NEBRASKA LEAVING
THE CWA ENVELOPED IN CLOUDS. TEMPERATURES REMAIN ABOVE FREEZING IN
MOST LOCATIONS.
UPPER TROUGH WAS MOVING ACROSS NEVADA AND CALIFORNIA AT 08Z WITH
MOISTURE STREAMING OFF THE EASTERN PACIFIC ACROSS THE SOUTHERN
PLAINS AND SOUTHERN KANSAS. TEMPERATURES TODAY SHOULD RISE INTO THE
LOW AND MID 40S WITH SOME WARM ADVECTION AND A FEW BREAKS IN THE
CLOUDS. SOME VERY LIGHT DRIZZLE/MIST OCCURRING ACROSS EAST CENTRAL
KANSAS AND WILL CONTINUE INTO MID MORNING. WITH TEMPERATURES AT
OR BELOW FREEZING IN SOME AREAS WILL ALSO MENTION SOME FREEZING
DRIZZLE AS WELL.
THE UPPER LOW WILL MOVE EAST INTO NEW MEXICO TODAY WITH INCREASING
MOISTURE ADVECTION ACROSS ALONG WITH ISENTROPIC LIFT OVER THE
FRONTAL BOUNDARY IN NORTH TEXAS DEVELOPING SOME SHOWERS AND A FEW
THUNDERSTORMS AS FAR NORTH AS SOUTHERN KANSAS THIS AFTERNOON. MODELS
NOW KEEP BETTER CHANCES SOUTH OF THE FORECAST AREA AND HAVE GONE DRY
SOUTH OF INTERSTATE 35.
TONIGHT THE UPPER TROUGH WILL SWING NORTHEAST OUT OF THE ROCKIES
WITH INCREASING FORCING FOR ASCENT ACROSS EASTERN KANSAS THROUGH THE
EVENING AND OVERNIGHT HOURS. GOOD MOISTURE FLUX INTO THE
AREA...FRONTOGENESIS...COUPLED JET STRUCTURE ALL POINT TO VERY HIGH
PROBABILITY OF SHOWERS AND ISOLATED THUNDER FOR MUCH OF THE CWA.
HIGHEST POPS WILL BE GENERALLY SOUTH OF INTERSTATE 70. FORECAST
SOUNDINGS ACROSS NORTH CENTRAL KANSAS DO NOT SHOW FREEZING RAIN
FORMING AND HAVE REMOVED IT FROM THE FORECAST...BUT THIS WILL NEED
TO BE MONITORED WITH LATER MODEL RUNS. THE UPPER TROUGH MOVES EAST
INTO ILLINOIS ON TUESDAY. HAVE PRECIPITATION ENDING DURING THE DAY
FROM WEST TO EAST AS THE UPPER LEVEL DEFORMATION AXIS MOVES EAST.
HIGHS TUESDAY WILL ONLY TOP OUT IN THE 40S WITH THE COOLEST TEMPS IN
THE NORTHEAST CORNER.
MID WEEK STILL LOOKING NICE WITH RIDGE BUILDING INTO THE CENTRAL
PLAINS FOR THANKSGIVING DAY BEFORE GIVING WAY TO THE NEXT UPPER
TROUGH MOVING INTO THE ROCKIES THURSDAY NIGHT AND INTO THE PLAINS ON
FRIDAY. FRONTAL BOUNDARY FORECAST TO MOVES ACROSS KANSAS WITH
ANOTHER SHOT OF SHOWERS AND A FEW THUNDERSTORMS ACROSS CENTRAL AND
EASTERN KANSAS. GFS BEEN FAIRLY CONSISTENT MOVING THE TROUGH THROUGH
THE PLAINS FRIDAY AND SATURDAY. LATEST RUN OF THE 00Z ECMWF IS
SLOWER AND FURTHER SOUTH WITH THE UPPER LOW AND HAS MORE ENERGY
MOVING ACROSS THE NORTHERN PLAINS. MAINTAINED EARLIER MODEL
CONSENSUS WITH CHANCE POPS ACROSS THE CWA FOR FRIDAY AND FRIDAY
NIGHT THEN DIMINISHING CHANCES ON SATURDAY. 00Z ECMWF MOVES THE
NORTHERN PLAINS THROUGH THROUGH EASTERN KANSAS WHILE CUTTING OFF THE
LOW OVER THE SOUTHERN PLAINS AND RETROGRESSING IT SOUTHWEST TO THE
WEST COAST OF MEXICO BY 00Z MONDAY. UPSHOT HAVE KEPT SUNDAY DRY AS
PRIOR FORECAST.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
213 PM CST MON NOV 21 2011
.DISCUSSION...
LOW CLOUDS/FOG WILL BE THE MAIN CHALLENGE TONIGHT AND TUESDAY. LOW
LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH INVERSION ACROSS THE
MIDWEST. CLOUDS HAD THINNED MOMENTARILY OVER PORTIONS OF EAST
CENTRAL MN AND WESTERN WISCONSIN DURING THE AFTERNOON.
HOWEVER...ANOTHER BATCH OF LOW CLOUDS WAS ADVANCING NORTHWARD OUT OF
IOWA. NAM40 RH PROGS SEEMS TO HAVE A GOOD HANDLE ON IT WITH CLOUDS
BECOMING MORE EXTENSIVE AGAIN OVER MUCH OF OUR EASTERN TWO THIRDS OF
OUR FORECAST AREA. SOUTHERLY AIRFLOW SHOULD BE ENOUGH TO KEEP SKIES
OVER WESTERN ONE THIRD MOSTLY CLEAR OVERNIGHT. LITTLE DIURNAL TEMP
CHANGE OVERNIGHT EXCEPT IN THE WEST AND IN SNOW COVER AREAS OF
CENTRAL MN...TEMPERATURES SHOULD DROP OFF IN THE TEENS.
MAX TEMPS ON TUESDAY WILL BE SLIGHTLY WARMER WITH HIGHS IN THE UPPER
30S TO LOWER 40S.
MODERATE TO STRONG WARM AIR ADVECTION WILL CONTINUE THROUGH THE END
OF THE WORK WEEK. LOW CLOUDS SHOULD FINALLY LIFT NORTHEAST AND
DISSIPATE ACROSS MUCH OF THE OUR BY WEDNESDAY. TEMPERATURES WILL
MODERATE INTO THE UPPER 40S TO MIDDLE 50S BY THANKSGIVING DAY.
MODELS HAVE BEEN CONSISTENT IN BRING SEVERAL SHORTWAVE TROUGHS FROM
THE PACIFIC INTO THE SOUTHWEST U.S. THESE WAVES WILL LIFT NORTHEAST
OVER THE MIDWEST OVER THE NEXT SEVERAL DAYS. NEXT CHANCE OF PRECIP
WILL OCCUR FRIDAY EVENING AND SATURDAY OVER OVER THE SOUTHEAST HALF
OF OUR FORECAST AREA.
THE EXTENDED OUTLOOK HAS A STRONG LOW PRESSURE SYSTEM TO LIFT
NORTHEAST OVER THE GREAT LAKES BY MONDAY OF NEXT WEEK. THIS SYSTEM
WILL DRAWN SOME COLDER AIR INTO THE NORTHERN PLAINS AND EVENTUALLY
ACROSS THE UPPER MIDWEST TUESDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
POORLY HANDLED STRATUS CONTINUES TO PLAGUE THE AREA THIS MORNING.
HAVE A PATCH OF IFR STRATUS THAT IS SLOWLY MOVING NORTH ACROSS ERN
MN AND WRN WI...THEN A PATCH OF VFR CIGS...FOLLOWED BY ANOTHER
BATCH OF MVFR STRATUS SE OF THAT. RUC H95 RH FIELD SHOWS IFR CIGS
SLOWLY DRIFTING NORTH THROUGH THE AFTERNOON. LVN ALREADY VFR...AND
PIREPS FROM SOUTH OF MSP INDICATING CIGS ARE SCT-BKN...SO DO THINK
A SCATTERING OUT IS IMMINENT AT MSP...FOLLOWED SHORTLY BY RNH.
TRIED TIMING NEXT ROUND OF MVFR CIGS NW UP INTO THE AREA...BUT ITS
NOT MOVING VERY FAST AT THE MOMENT...SO MAY BE LATER FOR A
RETURN TO RESTRICTED CIGS AT RNH/MSP THAN CURRENTLY INDICATED.
WHATEVER HAPPENS...CONFIDENCE HIGH GIVEN MODEL AGREEMENT IN
IFR/MVFR STRATUS SPREADING BACK ACROSS THE AREA TONIGHT...AS WEAK
LOW LEVEL FLOW NEVER REALLY CLEANS THINGS OUT THIS AFTERNOON...NOT
TO MENTION THE FACT THAT THE LIGHT S/SE WINDS IN PLACE WILL ONLY
HELP ADVECT THE BANK OF STRATUS FROM IA INTO CENTRAL WI BACK
ACROSS THE TERMINALS. ONLY FIELDS THAT MAY MISS OUT ON THE LOWER
CIGS WILL BE RWF/AXN ONCE AGAIN...BUT IT WILL BE VERY
CLOSE...HENCE THE SCT LOWER CLOUD LAYERS THERE. ANY IMPROVEMENT
WILL BE SLOW TO COME BY ON TUESDAY AS A SFC RIDGE AND ATTENDANT
LIGHT FLOW WILL BE OVER THE AREA. TEND TO AGREE WITH THE NAM THAT
ENOUGH OF A DRY SW PUSH WILL NOT ENTER THE MPX AREA UNTIL AFTER
18Z...WHEN ANY SIGNIFICANT CIG IMPROVEMENTS WILL LIKELY WAIT
UNTIL.
KMSP...LOW CONFIDENCE FORECAST THIS TAF PERIOD AS NO PIECE OF
GUIDANCE IS REALLY HANDLING THINGS ALL THAT WELL. IN GENERAL LIKE
THE IDEA OF THE GFSLAMP OF VFR CIGS COMING BACK FOR A BIT THIS
AFTERNOON...FOLLOWED BY A RETURN TO IFR CIGS TONIGHT. THIS MAKES
SENSE GIVEN CURRENT STRATUS/CLEAR SLOT/STRATUS CLOUD PATTERN. WITH
SFC RIDGE OVERHEAD...WILL SEE RATHER VARIABLE WINDS TONIGHT
THROUGH MOST OF TUESDAY...BUT BY THE END OF THE DAY...THE FIELD
SHOULD START TO SEE A MORE SW WIND BECOME ESTABLISHED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JM/MG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1221 PM CST MON NOV 21 2011
.AVIATION.../12Z TAF ISSUANCE/
LATEST REGIONAL OBSERVATIONS SATELLITE IMAGERY SHOWS A LARGE AREA
OF LOW CLOUD ACROSS THE NORTHLAND CURRENTLY. THIS CLOUD COVER HAS
INCREASE IN COVERAGE ACROSS OUR MN ZONES THIS MORNING...WITH SOME
DECREASE IN COVERAGE ACROSS OUR WI ZONES. HOWEVER OVERALL THINK
THAT THE LOW CLOUDS SHOULD STAY FAIRLY WIDESPREAD ACROSS OUR CWA
THROUGH THE TAF PERIOD DUE TO LIMITED MIXING AND DRY AIR ADVECTION
EXPECTED. CIGS WILL GENERALLY BE IN THE IFR/LOW MVFR RANGE...AND
THERE WILL BE AREAS OF FOG WITH IFR/MVFR VSBYS AS WELL.
&&
.PREV DISCUSSION... /ISSUED 1015 AM CST MON NOV 21 2011/
UPDATE...EXTENSIVE STRATUS DECK COVERING A LARGE PART OF CWA.
COLD MOIST LAYER NEAR SFC IS BEING TOPPED BY A LAYER OF WARM AIR
ADVECTION PRODUCED BY DEPARTING SFC HIGH. SMALL AREA OF CLEARING
OCCURRING OVER ERN BAYFIELD TO ASHLAND/IRON COUNTIES AS INITIAL
HOLE IN DECK ALLOWED FOR AN AREA OF INCREASED MIXING WITHIN
RELATIVELY SHALLOW MOIST LAYER. FCST RUC13 SNDGS SHOW DEVELOPING
SUBSIDENCE INVERSION PROFILE SO SUSPECT THAT IT MAY BE TOUGH TO
CLEAR CLOUDS FROM MANY LOCATIONS TODAY. LOWERED TEMPS/INCREASED SKY
GRIDS/ADDED FOG TO ZFP/GRIDS.
PREV DISCUSSION... /ISSUED 553 AM CST MON NOV 21 2011/
AVIATION...11/21/12Z ISSUANCE...
SURFACE RIDGING OVER SNOW COVER AND A FAST AND DEEP FLOW OF WARM
DRY AIR OF PACIFIC ORIGIN IS RAPIDLY STABILIZING THE COLUMN. SO...
WARM AIR IS TRAPPING A SHALLOW LAYER OF INCREASINGLY MOIST AIR
NEAR THE SURFACE. AREAS OF IFR IN LOW STRATUS OVER NORTHWEST
WISCONSIN...THE DULUTH AREA NORTHWARD THROUGH THE ARROWHEAD WILL
ONLY SLOWLY BECOME VFR SCATTERED OR CLEAR THIS MORNING. THERE IS A
THREAT OF IFR CONDITIONS IN STRATUS AGAIN DEVELOPING THIS EVENING.
PREV DISCUSSION... /ISSUED 324 AM CST MON NOV 21 2011/
SHORT TERM...
CURRENT SAT SUBTRACTION CURVE IMAGERY AND SFC OBS SHOWING
GRADUALLY EXPANDING AREA OF LOW CLOUDS OVER THE EASTERN HALF OF
THE FORECAST AREA. TEMPERATURES AT 300 AM WERE GENERALLY IN THE
TEENS TO LOW 20S UNDER THE CLOUD COVER. MOSTLY CLEAR SKIES OVER
THE WESTERN ZONES ALLOWED EARLY MORNING TEMPS TO DROP INTO THE
SINGLE DIGITS. A FEW LOCATIONS IN THE IRON RANGE REGION SAW SUB
ZERO TEMPS BRIEFLY BEFORE A DECK HIGH CLOUDS ARRIVED AND TEMPS
REBOUNDED.
THE REGION WILL BE POSITIONED ON THE BACK SIDE OF EXITING HIGH
PRESSURE AS A SPLIT ZONAL FLOW ALLOWS FOR TWO SHORT WAVES TO TRACK
TO THE NORTH AND SOUTH OF THE WESTERN GREAT LAKES THROUGH TUESDAY.
A PERSISTENT SW 25-30 LLJ WILL RESULT IN INCREASING MOISTURE AND
RISING H85 TEMPS TODAY AND TONIGHT. LATEST NAM BUFR SOUNDINGS AT
KELO/KHIB/KDLH SUGGEST PROFILES BECOME SATURATED TO 900 MB BY LATE
THIS EVENING. THE LOW LEVEL MOISTURE AND FORCING FROM WAA
COMBINED WITH CLOUD TOP TEMPS AROUND NEGATIVE 5 C WOULD SUPPORT
PATCHY DZ/FZDZ. TO ACCOUNT FOR THIS...INCREASED CLOUD COVER
OVERNIGHT AND INTRODUCED PATCHY FOG TO MN ARROWHEAD REGION AT THIS
TIME.
OUTLOOK...TUESDAY NIGHT THROUGH MONDAY...
NORTH-SOUTH SURFACE RIDGING OVER OUR AREA...WITH A VERY WEAK SURFACE
GRADIENT IS ACCOMPANIED BY SIGNIFICANT WARMING ALOFT AND A CONTINUED
DEEP ZONAL FLOW OF WARM AND VERY DRY AIR OF PACIFIC ORIGIN. THE
WARM ADVECTION AND HEIGHT GRADIENT INCREASES AT ALL LEVELS...AND SO
DOES THE STABILITY AND TENDENCY OF WINDS TO INCREASE AND VEER WITH
HEIGHT...THURSDAY AND THURSDAY NIGHT. THE GFS SEEMS TO OVERDO A
WEAK AND SHALLOW COLD FRONT WHERE THE EUROPEAN SUGGESTS A SHALLOW
REPLENISHMENT OF VERY SHALLOW RELATIVELY COLD AIR AT THE SURFACE AND
CONTINUED RIDGING AND WARMTH ALOFT FRIDAY AND FRIDAY NIGHT. AS A
RESULT...WE REMAIN AWARE OF A POSSIBILITY OF LOW CLOUDS AND CHILLIER
THAN EXPECTED WEATHER TUESDAY NIGHT THROUGH FRIDAY...ESPECIALLY NEAR
THE BIG LAKE. ANOTHER COLD FRONT BRINGS A CHANCE OF PRECIPITATION
AND DEEPER COLD AIR LATE FRIDAY NIGHT AND SATURDAY. EVEN WITH THE
FRONT...TEMPERATURES REMAIN WELL ABOVE SEASONABLE NORMALS SATURDAY
WITH ANOTHER DRY WARM-UP BEGINNING SUNDAY AND CONTINUING MONDAY.
ALL THE MODELS HAVE ANOTHER COLD FRONT APPROACHING LATE MONDAY...
THE EUROPEAN SUGGESTS THAT THIS MAY BE THE BEGINNING OF A PATTERN
CHANGE WHILE THE GFS TENDS TO KEEP OUR AREA IN DRY WARM PACIFIC AIR.
&&
.POINT TEMPS/POPS...
DLH 28 23 37 24 / 10 10 10 10
INL 25 13 36 21 / 10 10 10 10
BRD 29 16 36 22 / 0 10 0 0
HYR 33 22 37 22 / 10 10 0 10
ASX 33 24 37 26 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...BERDES
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1154 AM CST MON NOV 21 2011
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
ISSUE FOR TODAY IS MESSY CLOUD FORECAST. THAT AND SNOW COVER WILL BE
PROBLEMATIC FOR TEMPERATURES TODAY. CURRENT SURFACE RIDGE OF HIGH
PRESSURE EXTENDS EAST ACROSS WI INTO CENTRAL MN. TEMPERATURES ACROSS
CENTRAL MN OVER FRESH SNOWPACK DROPPED INTO THE SINGLE DIGITS...BUT
HAVE RECOVERED SOME IN THE WEST AS WINDS HAVE COME UP A BIT.
EXPANDING AREA OF STRATUS IN SHALLOW SELY FLOW UNDER INVERSION HAS
BEEN STEADILY PUSHING NE ACROSS SE/EC MN OVERNITE. WITH LOW LEVEL
WINDS HAVING AN EASTERLY COMPONENT TODAY...CLOUDS MAY BE DIFFICULT
TO REMOVE. LOWERED MAX TEMP FOR THIS AFTERNOON SEVERAL DEGREES WC
WI INTO ADJOINING AREAS OF MN.
ELY FLOW TONIGHT WILL BRING RISK OF STRATUS IN E MN INTO WI. 06Z
NAM 925 MB RH TRIES TO PICK UP ON THIS. TRENDED CLOUD COVER UPWARD
SOME FOR TONIGHT...BUT WILL LET NEXT SHIFT MAKE FURTHER ADJUSTMENTS
WHEN WE SEE HOW CLOUDS BEHAVE TODAY.
PRECIP FROM SYSTEM TRACKING ACROSS MO INTO OHIO VALLEY ON TUESDAY
WILL STAY SE OF AREA...BUT PROBABLY ENUF CLOUD COVER TO KEEP TEMPS
DOWN A FEW DEGREES.
WARM UP GETS INTO FULL GEAR WEDNESDAY AS WE GET INTO BROAD SWLY FLOW
AHEAD OF FRIDAY`S COLD FRONT. TEMPS PROBABLY WILL GET DAMPED A BIT
FROM REMAINING SNOW COVER ACROSS N PORTIONS OF CWA. SOME RISK OF
LOWER CLOUDS THURSDAY ACROSS N AREAS AS DEWPOINTS BEGIN TO RISE INTO
MID 30S.
DIDN`T MAKE SIGNIFICANT CHANGES IN PRECIP FORECAST FOR FRI/SAT. GFS
HAS CONSIDERABLY HIGHER QPF THAN ECMWF (STILL ONLY .10 TO .20) WITH
MAIN AREA ACROSS SE MN INTO WI. ANY PCPN WOULD BEGIN AS RAIN WITH A
CHANGE TO SNOW AS COLD FRONT MOVES THRU AREA. 00Z GEM IS SIMILAR TO
THE GFS SOLUTION. COOLING LOOKS RATHER BRIEF WITH UPPER RIDGE
REBUILDING EARLY NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
.AVIATION.../18Z TAF ISSUANCE/
POORLY HANDLED STRATUS CONTINUES TO PLAGUE THE AREA THIS MORNING.
HAVE A PATCH OF IFR STRATUS THAT IS SLOWLY MOVING NORTH ACROSS ERN
MN AND WRN WI...THEN A PATCH OF VFR CIGS...FOLLOWED BY ANOTHER
BATCH OF MVFR STRATUS SE OF THAT. RUC H95 RH FIELD SHOWS IFR CIGS
SLOWLY DRIFTING NORTH THROUGH THE AFTERNOON. LVN ALREADY VFR...AND
PIREPS FROM SOUTH OF MSP INDICATING CIGS ARE SCT-BKN...SO DO THINK
A SCATTERING OUT IS IMMINENT AT MSP...FOLLOWED SHORTLY BY RNH.
TRIED TIMING NEXT ROUND OF MVFR CIGS NW UP INTO THE AREA...BUT ITS
NOT MOVING VERY FAST AT THE MOMENT...SO MAY BE LATER FOR A
RETURN TO RESTRICTED CIGS AT RNH/MSP THAN CURRENTLY INDICATED.
WHATEVER HAPPENS...CONFIDENCE HIGH GIVEN MODEL AGREEMENT IN
IFR/MVFR STRATUS SPREADING BACK ACROSS THE AREA TONIGHT...AS WEAK
LOW LEVEL FLOW NEVER REALLY CLEANS THINGS OUT THIS AFTERNOON...NOT
TO MENTION THE FACT THAT THE LIGHT S/SE WINDS IN PLACE WILL ONLY
HELP ADVECT THE BANK OF STRATUS FROM IA INTO CENTRAL WI BACK
ACROSS THE TERMINALS. ONLY FIELDS THAT MAY MISS OUT ON THE LOWER
CIGS WILL BE RWF/AXN ONCE AGAIN...BUT IT WILL BE VERY
CLOSE...HENCE THE SCT LOWER CLOUD LAYERS THERE. ANY IMPROVEMENT
WILL BE SLOW TO COME BY ON TUESDAY AS A SFC RIDGE AND ATTENDANT
LIGHT FLOW WILL BE OVER THE AREA. TEND TO AGREE WITH THE NAM THAT
ENOUGH OF A DRY SW PUSH WILL NOT ENTER THE MPX AREA UNTIL AFTER
18Z...WHEN ANY SIGNIFICANT CIG IMPROVEMENTS WILL LIKELY WAIT
UNTIL.
KMSP...LOW CONFIDENCE FORECAST THIS TAF PERIOD AS NO PIECE OF
GUIDANCE IS REALLY HANDLING THINGS ALL THAT WELL. IN GENERAL LIKE
THE IDEA OF THE GFSLAMP OF VFR CIGS COMING BACK FOR A BIT THIS
AFTERNOON...FOLLOWED BY A RETURN TO IFR CIGS TONIGHT. THIS MAKES
SENSE GIVEN CURRENT STRATUS/CLEAR SLOT/STRATUS CLOUD PATTERN. WITH
SFC RIDGE OVERHEAD...WILL SEE RATHER VARIABLE WINDS TONIGHT
THROUGH MOST OF TUESDAY...BUT BY THE END OF THE DAY...THE FIELD
SHOULD START TO SEE A MORE SW WIND BECOME ESTABLISHED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1015 AM CST MON NOV 21 2011
.UPDATE...EXTENSIVE STRATUS DECK COVERING A LARGE PART OF CWA.
COLD MOIST LAYER NEAR SFC IS BEING TOPPED BY A LAYER OF WARM AIR
ADVECTION PRODUCED BY DEPARTING SFC HIGH. SMALL AREA OF CLEARING
OCCURRING OVER ERN BAYFIELD TO ASHLAND/IRON COUNTIES AS INITIAL
HOLE IN DECK ALLOWED FOR AN AREA OF INCREASED MIXING WITHIN
RELATIVELY SHALLOW MOIST LAYER. FCST RUC13 SNDGS SHOW DEVELOPING
SUBSIDENCE INVERSION PROFILE SO SUSPECT THAT IT MAY BE TOUGH TO
CLEAR CLOUDS FROM MANY LOCATIONS TODAY. LOWERED TEMPS/INCREASED SKY
GRIDS/ADDED FOG TO ZFP/GRIDS.
&&
.PREV DISCUSSION... /ISSUED 553 AM CST MON NOV 21 2011/
AVIATION...11/21/12Z ISSUANCE...
SURFACE RIDGING OVER SNOW COVER AND A FAST AND DEEP FLOW OF WARM
DRY AIR OF PACIFIC ORIGIN IS RAPIDLY STABILIZING THE COLUMN. SO...
WARM AIR IS TRAPPING A SHALLOW LAYER OF INCREASINGLY MOIST AIR
NEAR THE SURFACE. AREAS OF IFR IN LOW STRATUS OVER NORTHWEST
WISCONSIN...THE DULUTH AREA NORTHWARD THROUGH THE ARROWHEAD WILL
ONLY SLOWLY BECOME VFR SCATTERED OR CLEAR THIS MORNING. THERE IS A
THREAT OF IFR CONDITIONS IN STRATUS AGAIN DEVELOPING THIS EVENING.
PREV DISCUSSION... /ISSUED 324 AM CST MON NOV 21 2011/
SHORT TERM...
CURRENT SAT SUBTRACTION CURVE IMAGERY AND SFC OBS SHOWING
GRADUALLY EXPANDING AREA OF LOW CLOUDS OVER THE EASTERN HALF OF
THE FORECAST AREA. TEMPERATURES AT 300 AM WERE GENERALLY IN THE
TEENS TO LOW 20S UNDER THE CLOUD COVER. MOSTLY CLEAR SKIES OVER
THE WESTERN ZONES ALLOWED EARLY MORNING TEMPS TO DROP INTO THE
SINGLE DIGITS. A FEW LOCATIONS IN THE IRON RANGE REGION SAW SUB
ZERO TEMPS BRIEFLY BEFORE A DECK HIGH CLOUDS ARRIVED AND TEMPS
REBOUNDED.
THE REGION WILL BE POSITIONED ON THE BACK SIDE OF EXITING HIGH
PRESSURE AS A SPLIT ZONAL FLOW ALLOWS FOR TWO SHORT WAVES TO TRACK
TO THE NORTH AND SOUTH OF THE WESTERN GREAT LAKES THROUGH TUESDAY.
A PERSISTENT SW 25-30 LLJ WILL RESULT IN INCREASING MOISTURE AND
RISING H85 TEMPS TODAY AND TONIGHT. LATEST NAM BUFR SOUNDINGS AT
KELO/KHIB/KDLH SUGGEST PROFILES BECOME SATURATED TO 900 MB BY LATE
THIS EVENING. THE LOW LEVEL MOISTURE AND FORCING FROM WAA
COMBINED WITH CLOUD TOP TEMPS AROUND NEGATIVE 5 C WOULD SUPPORT
PATCHY DZ/FZDZ. TO ACCOUNT FOR THIS...INCREASED CLOUD COVER
OVERNIGHT AND INTRODUCED PATCHY FOG TO MN ARROWHEAD REGION AT THIS
TIME.
OUTLOOK...TUESDAY NIGHT THROUGH MONDAY...
NORTH-SOUTH SURFACE RIDGING OVER OUR AREA...WITH A VERY WEAK SURFACE
GRADIENT IS ACCOMPANIED BY SIGNIFICANT WARMING ALOFT AND A CONTINUED
DEEP ZONAL FLOW OF WARM AND VERY DRY AIR OF PACIFIC ORIGIN. THE
WARM ADVECTION AND HEIGHT GRADIENT INCREASES AT ALL LEVELS...AND SO
DOES THE STABILITY AND TENDENCY OF WINDS TO INCREASE AND VEER WITH
HEIGHT...THURSDAY AND THURSDAY NIGHT. THE GFS SEEMS TO OVERDO A
WEAK AND SHALLOW COLD FRONT WHERE THE EUROPEAN SUGGESTS A SHALLOW
REPLENISHMENT OF VERY SHALLOW RELATIVELY COLD AIR AT THE SURFACE AND
CONTINUED RIDGING AND WARMTH ALOFT FRIDAY AND FRIDAY NIGHT. AS A
RESULT...WE REMAIN AWARE OF A POSSIBILITY OF LOW CLOUDS AND CHILLIER
THAN EXPECTED WEATHER TUESDAY NIGHT THROUGH FRIDAY...ESPECIALLY NEAR
THE BIG LAKE. ANOTHER COLD FRONT BRINGS A CHANCE OF PRECIPITATION
AND DEEPER COLD AIR LATE FRIDAY NIGHT AND SATURDAY. EVEN WITH THE
FRONT...TEMPERATURES REMAIN WELL ABOVE SEASONABLE NORMALS SATURDAY
WITH ANOTHER DRY WARM-UP BEGINNING SUNDAY AND CONTINUING MONDAY.
ALL THE MODELS HAVE ANOTHER COLD FRONT APPROACHING LATE MONDAY...
THE EUROPEAN SUGGESTS THAT THIS MAY BE THE BEGINNING OF A PATTERN
CHANGE WHILE THE GFS TENDS TO KEEP OUR AREA IN DRY WARM PACIFIC AIR.
&&
.POINT TEMPS/POPS...
DLH 28 23 37 24 / 10 10 10 0
INL 25 13 36 22 / 10 10 10 0
BRD 29 16 36 23 / 0 10 0 0
HYR 33 22 37 21 / 10 10 0 0
ASX 33 24 37 25 / 10 10 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1218 PM CST MON NOV 21 2011
.AVIATION...18Z KGRI TAF. LIGHT SOUTH WINDS ARE EXPECTED THROUGH
THE DAY WITH LIGHT AND VARIABLE WINDS TONIGHT. A LIGHT NORTHWEST
WIND IS THEN EXPECTED TO DEVELOP BY MID TUESDAY MORNING. MID TO
HIGH CLOUDS WILL QUICKLY MOVE INTO THE AREA THIS AFTERNOON AND
REMAIN THROUGHOUT MUCH OF THE PERIOD. HOWEVER...VFR CONDITIONS
WILL PERSIST THROUGH TOMORROW.
&&
.PREV DISCUSSION... /ISSUED 1144 AM CST MON NOV 21 2011/
UPDATE...FOR TONIGHT...12Z NAM AND GFS HAVE COME IN FURTHER SOUTH
WITH THE PRECIPITATION AND WARMER IN AREAS THAT ARE EXPECTED TO
SEE PRECIPITATION. IN ADDITION...THE 09Z SREF ENSEMBLES ARE
INDICATING LESS THAN A 5 PERCENT CHANCE OF 0.01 LIQUID
ACCUMULATION IN THE TRI CITIES...KEEPING ACCUMULATING RAIN TO THE
SOUTH OF THE TRI CITIES AND PRIMARILY OVER KANSAS. THE ENSEMBLE
MEAN TEMPERATURE IS AT OR ABOVE 32F FOR ALL LOCATIONS WITH POPS OF
15 PERCENT OR HIGHER...THIS IS PRIMARILY REFERRING TO KANSAS ZONES
AS THESE ARE ABOUT THE ONLY ZONES WITH HIGHER POPS. THEREFORE...THE
POSSIBILITY OF FREEZING RAIN LATE TONIGHT INTO EARLY TOMORROW
MORNING HAS DECREASED AND SEEMS UNLIKELY. CONSEQUENTLY...FREEZING
RAIN HAS BEEN PULLED FROM THE FORECAST AT LEAST FOR NOW...ALTHOUGH
IT WILL STILL BE A CLOSE CALL AND WILL BE CLOSELY WATCHED BY
FUTURE FORECAST SHIFTS.
PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS HASTINGS NE
1144 AM CST MON NOV 21 2011
.UPDATE...FOR TONIGHT...12Z NAM AND GFS HAVE COME IN FURTHER SOUTH
WITH THE PRECIPITATION AND WARMER IN AREAS THAT ARE EXPECTED TO
SEE PRECIPITATION. IN ADDITION...THE 09Z SREF ENSEMBLES ARE
INDICATING LESS THAN A 5 PERCENT CHANCE OF 0.01 LIQUID
ACCUMULATION IN THE TRI CITIES...KEEPING ACCUMULATING RAIN TO THE
SOUTH OF THE TRI CITIES AND PRIMARILY OVER KANSAS. THE ENSEMBLE
MEAN TEMPERATURE IS AT OR ABOVE 32F FOR ALL LOCATIONS WITH POPS OF
15 PERCENT OR HIGHER...THIS IS PRIMARILY REFERRING TO KANSAS ZONES
AS THESE ARE ABOUT THE ONLY ZONES WITH HIGHER POPS. THEREFORE...THE
POSSIBILITY OF FREEZING RAIN LATE TONIGHT INTO EARLY TOMORROW
MORNING HAS DECREASED AND SEEMS UNLIKELY. CONSEQUENTLY...FREEZING
RAIN HAS BEEN PULLED FROM THE FORECAST AT LEAST FOR NOW...ALTHOUGH
IT WILL STILL BE A CLOSE CALL AND WILL BE CLOSELY WATCHED BY
FUTURE FORECAST SHIFTS.
&&
.PREV DISCUSSION... /ISSUED 544 AM CST MON NOV 21 2011/
AVIATION...12Z KGRI TAF. VFR CONDITIONS ARE FORECAST. A SHORTWAVE
TROUGH MOVING INTO THE SOUTHERN PLAINS WILL LOWER CEILINGS TO MID-
LEVEL. NOT TOO FAR SOUTH OF THE TERMINAL THERE WILL BE MUCH LOWER
CEILINGS BETWEEN 06Z AND 12Z TUESDAY MORNING ALONG WITH THE
POSSIBILITY OF FREEZING RAIN. FOR NOW IT LOOKS LIKE PRECIPITATION
SHOULD REMAIN BARELY SOUTH OF THE TERMINAL...BUT CLOSE. WIND
SHOULD REMAIN LIGHT.
PREV DISCUSSION... /ISSUED 515 AM CST MON NOV 21 2011/
SHORT TERM...THROUGH WEDNESDAY NIGHT. BY FAR THE MOST
SIGNIFICANT ISSUE DURING THE NEXT 72 HOURS INVOLVES PRECIPITATION
CHANCES/PRECIPITATION TYPE WITH THE SYSTEM TONIGHT INTO TUESDAY
MORNING...AND WHETHER SOME AREAS COULD POSSIBLY EXPERIENCE SOME
LIGHT ICING.
AT 10Z...OBJECTIVE SURFACE ANALYSIS AND AUTOMATED OBSERVATIONS
REVEALS A BROAD RIDGE AXIS FROM THE GREAT LAKES REGION INTO THE
CENTRAL/SOUTHERN PLAINS...WITH CALM TO VERY LIGHT BREEZES IN PLACE
ACROSS THE CWA...AND SIGNS OF LIGHT SOUTHERLY RETURN FLOW EVIDENT
JUST OFF TO THE WEST. WITH ONLY A THIN CIRRUS VEIL OVER MOST
AREAS...TEMPERATURES EARLY THIS MORNING HAVE TUMBLED WELL INTO THE
14-19 DEGREE RANGE MOST SPOTS. HOWEVER...THE FAR NORTHWEST FRINGES
OF A PESKY STRATUS DECK HAS SNUCK INTO PRIMARILY A PORTION OF
MITCHELL COUNTY KS IN THE CWA...HOLDING UP TEMPS UNDER IT SEVERAL
DEGREES WARMER. ALOFT...LATEST WATER VAPOR IMAGERY AND SHORT TERM
MODEL GUIDANCE FEATURES QUASI-ZONAL FLOW OVER THE CENTRAL
PLAINS...JUST AHEAD OF A STOUT TROUGH ACROSS THE SOUTHWEST
CONUS...ANCHORED BY A 500MB VORT MAX SWINGING ACROSS SOUTHERN
CALIFORNIA.
THROUGH THE DAYLIGHT HOURS...A DRY FORECAST REMAINS IN
PLACE...WITH ONLY A GRADUAL INCREASE IN MAINLY HIGH LEVEL CLOUDS.
THE AFOREMENTIONED LOW STRATUS DECK ACROSS THE EXTREME SOUTHEAST
CWA AT THIS HOUR SHOULD SHUNT JUST OFF TO THE EAST WITH TIME...AND
ESSENTIALLY BE A NON-ISSUE TODAY PER LATEST RUC RELATIVE HUMIDITY
PROGS. WITH THE GRADUAL INCREASE IN CLOUDS...THE COLD START...AND
ONLY LIGHT SOUTHERLY FLOW...NOT GOING TO BE A BIG WARM UP
TODAY...AND NUDGED HIGHS DOWN 1-2 DEGREES...PUTTING MOST OF THE
CWA RIGHT AROUND 43-ISH.
FOR 00Z THIS EVENING AND INTO MID-MORNING TUESDAY...ALL EYES ARE
ON PRECIPITATION CHANCES MOVING IN. ALTHOUGH UNCERTAINTY IS
UNFORTUNATELY AT A FAIRLY HIGH LEVEL FOR ONLY BEING 12-24 HOURS
OUT...DECIDED TO BREAK POP/WX GRIDS INTO SEVERAL 3-6 HOUR CHUNKS
TONIGHT. THE BASIC STORY INVOLVES THE SOUTHWEST CONUS TROUGH
EJECTING OUT OF THE SOUTHERN HIGH PLAINS TONIGHT AND INTO THE
CENTRAL PLAINS IN A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED
FASHION...WITH THE MAIN 500MB TROUGH AXIS FINALLY CLEARING THE
EASTERN CWA BY SOMETIME TUESDAY MORNING. UNFORTUNATELY...VARIOUS
MODELS INCLUDING THE 06Z NAM/GFS...00Z ECMWF...00Z 4KM WRF-NMM ALL
VARY REGARDING HOW AGGRESSIVE THIS QUICK MOVING SYSTEM WILL BE
REGARDING PRECIPITATION AMOUNTS...WITH THE ECMWF BARELY SPITTING
OUT A FEW HUNDREDTHS IN ITS QPF FIELD...WHILE THE LATEST NAM
ACTUALLY TRIES CLOSING OFF THE MID LEVEL CIRCULATION AS IT CROSSES
THE SOUTHERN CWA...THUS GENERATING A STOUT DEFORMATION ZONE WITH
PRECIP AMOUNTS OF AT LEAST 0.25-0.50 INCH ADVERTISED ACROSS
SEVERAL COUNTIES. LEANING TOWARD THE SREF GIVEN THE INHERENT
UNCERTAINTY...ENDED UP BOOSTING POPS SIGNIFICANTLY OVERNIGHT FROM
PREVIOUS FORECAST ACROSS SEVERAL SOUTHEAST COUNTIES INTO THE 50-70
PERCENT RANGE...AND EXPANDING 20-30 PERCENT CHANCES NORTHWARD
ROUGHLY AS FAR AS AN ELWOOD-SILVER CREEK LINE INCLUDING THE TRI
CITIES. UNFORTUNATELY...THE FARTHER NORTH PRECIP MIGHT DEVELOP...THE
HIGHER THE RISK THAT TEMPS AT THE SURFACE COULD BE FLIRTING WITH
THE FREEZING MARK...IF NOT DROPPING AT LEAST A FEW DEGREES BELOW
IT. AGAIN...UNCERTAINTY ABOUNDS WITH RAW MET/MAV GUIDANCE
SUGGESTING AT LEAST LIGHT FREEZING RAIN POSSIBLE PER LOW
TEMPERATURE PROGS...WHILE THE 06Z NAM KEEPS NEARLY ALL AREAS
AT/ABOVE 32 WITH ONLY A RAIN RISK. PER THE SREF...THE ODDS OF
PRECIPITATION FALLING AS FREEZING RAIN ARE QUITE SMALL...BUT
HEDGING ON THE SIDE OF CAUTION OPTED TO GO INTO A BIT OF DETAIL IN
THE HWO TO ACKNOWLEDGE THE POSSIBILITY. HOPEFULLY...THIS ALL ENDS
UP BEING NOTHING MORE THAN A COLD RAIN...WITH TEMPS CLOSE ENOUGH
TO 32 OR SLIGHTLY ABOVE AT TO KEEP ANY LIGHT ICING AT A
MINIMUM...AND THIS SEEMS TO BE THE CASE FOR NOW. OF LESSER CONCERN
BUT ONE THAT SHOULD BE MENTIONED IS THAT THE 06Z NAM ADVERTISES AT
LEAST 100 J/KG ELEVATED CAPE NOSING UP INTO KS ZONES
OVERNIGHT...AND AT LEAST ISOLATED THUNDERSTORMS ARE NOT OUT OF THE
QUESTION...AND MAY NEED INCLUDED BY FOLLOWING SHIFTS IF THIS
INSTABILITY SIGNAL PERSISTS.
FOR THE TUESDAY DAYTIME PERIOD...MAIN CHANGE WAS TO LINGER A
SLIGHT CHANCE OF PRECIP IN FAR SOUTHEAST ZONES THROUGH
15Z...ALTHOUGH THE LATEST NAM...WHICH REPRESENTS THE
SLOWEST/STRONGEST OF SOLUTIONS...SUGGESTS THAT SOMETHING COULD EVEN
LINGER BEYOND 15Z...BUT NOT WILLING TO BITE ON THIS YET.
OTHERWISE...THE SHORT STORY FROM MID-DAY TUESDAY THROUGH WEDNESDAY
NIGHT IS THAT LEGITIMATELY DRY WEATHER WILL OVERTAKE THE AREA AS A
BROAD RIDGE OVERTAKES THE CENTRAL CONUS. IN FACT...ZEROED OUT POPS
CWA-WIDE DURING THE TUES NIGHT-WED NIGHT TIME FRAME IN THIS
SUBSIDENT PATTERN.
TEMP WISE...WILL COUNT ON MODEST DOWNSLOPE NORTHWESTERLY LOW LEVEL
WIND COMPONENT AND INCREASING SUNSHINE TO BOOST TUESDAY HIGHS BACK
INTO THE LOW 50S MOST AREAS...WHICH IS ABOUT THE SAME AS PREVIOUS
FORECAST. NUDGED DOWN TUES NIGHT LOWS ROUGHLY 2 DEGREES ON
AVERAGE...PUTTING MOST AREAS INTO THE MID/UPPER 20S. ON
WEDNESDAY...CONTINUED LOW LEVEL WARM AIR ADVECTION AND PLENTY OF
SUNSHINE WILL BOOST THINGS SEVERAL MORE DEGREES...AND BUMPED UP
PREVIOUS FORECAST A FEW DEGREES NOW PUTTING NEARLY ALL AREAS INTO
THE LOW 60S...OR 10-15 DEGREES ABOVE NORMAL FOR LATE NOVEMBER.
LONG TERM...THANKSGIVING THROUGH SUNDAY.
THE LONG TERM WILL BE FOLLOWING MOSTLY A BLEND OF 00Z ECMWF ENSEMBLE
MEANS. UPPER LEVEL RIDGE AXIS WILL BE SLIPPING OFF JUST TO THE EAST
OF THE CWA FOR THANKSGIVING. ALSO...THANKSGIVING SOUNDINGS LOOK
EXTREMELY DRY WITH VERY STRONG SUBSIDENCE STILL OCCURRING. A SURFACE
TROUGH IN THE LEE OF THE ROCKY MOUNTAINS WILL HELP TO KICK UP THE
BREEZE FROM THE SOUTH A BIT AS WELL. THIS WILL BE OUR WARMEST DAY OF
THE EXTENDED WITH THE EXPECTED WARM AIR ADVECTION AND TEMPERATURES
PUSHING 60. THE ONLY CAVEAT IS THAT SOME CIRRUS COULD OCCUR IN
ASSOCIATION WITH AN UPPER LEVEL JET STREAK HELP KEEP TEMPERATURES
DOWN A BIT.
MODELS ARE GENERALLY INDICATING A SHORTWAVE TROUGH TO SWING THROUGH
FROM THE NORTHWEST FOR FRIDAY/FRIDAY NIGHT. WITH DRY AIR IN
PLACE...THE BEST BET FOR ANY PRECIPITATION WILL BE IN OUR EASTERN
CWA WHERE WHERE SOME LOWER LEVEL GULF INFLOW COULD SPREAD INTO THAT
AREA WITH THE AID OF SOME BACKING WIND AS THE SURFACE COLD FRONT
APPROACHES. THE TRI-CITIES WILL MORE THAN LIKELY BE TOO FAR WEST TO
GET PRECIPITATION. MODELS ARE CURRENTLY INDICATING A CLOSED AND
EVENTUALLY CUTOFF LOW OVER THE SOUTHWEST UNITED STATES/MEXICO WHICH
SHOULD BE FAR ENOUGH SOUTH NOT TO INTERFERE WITH CENTRAL PLAINS
WEATHER.
SATURDAY AND SUNDAY ARE LOOKING PROMISING FOR MORE DRY WEATHER WITH
A RATHER SUBSTANTIAL RIDGE COMING IN BEHIND THE SHORTWAVE TROUGH
FROM FRIDAY/FRIDAY NIGHT. SATURDAY COULD BE QUITE
BREEZY...HOWEVER...AS A SURFACE HIGH BUILDS IN. MODELS DIFFER BY
VARYING DEGREES ON TEMPERATURES...BUT GENERALLY LOOK RATHER
SEASONABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1206 PM CST MON NOV 21 2011
.AVIATION...
ALTHOUGH THERE WILL BE SOME BRIEF BREAKS INTO VFR TODAY...THE
MAJORITY OF THIS PERIOD WILL BE MVFR WITH A LOWERING TO EARLY
TUESDAY IFR. A SHORT WINDOW OF CONVECTION TOMORROW MORNING INTO
AFTERNOON WITH PERIODS OF SHOWERS TRANSITIONING TO MODERATE RAIN
WITH EMBEDDED STORMS. NOT OVERLY CONFIDENT ON FREQUENCY NOR STRENGTH
OF STORMS AS RECENT MODELS HAVE A PROGRESSIVELY SE-MOVING THIN LINE
OF RAIN/TS ADVANCING INTO AN MARGINALLY UNSTABLE ENVIRONMENT (DRY
AIR ALOFT WITH A 5K FT WARM LAYER). THERE SHOULD BE ENOUGH FORCING
RIGHT ALONG A PRE-FRONTAL TROUGH TO PROVIDE THE VERY SHORT TERM
LIFT NEEDED TO WEAKEN (OR BREAK) THIS CAP SO HAVE PROB30`ED OR
TEMPO`ED THUNDER. A DECENT LOW LEVEL JET OF AROUND 35-30 KTS RIGHT
OFF THE SFC SHOULD TRANSFER DOWN WITHIN CONVECTION SO BEWARE OF
SUDDEN SW`ERN (SPEED) SHEAR IN THE LOWER 3K FT. TIMING HAS THIS
TSRA LINE PASSING ACROSS KCLL AT AROUND 15-16Z...METRO AROUND
NOON...TO THE COAST AROUND 20-22Z. KGLS MAY HAVE TUESDAY MORNING
PERIODS OF MVFR FOG...WITH A LESSER CHANCE OF DEVELOPING SEA FOG
THAT COULD QUICKLY DROP THE ISLAND INTO (L)IFR. 31
&&
.PREV DISCUSSION... /ISSUED 1031 AM CST MON NOV 21 2011/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
AT 16Z...A COLD FRONT EXTENDED SOUTH FROM LONGVIEW TO PALASTINE TO
CALDWELL. THE FRONT APPEARS TO BE RETREATING NORTH AS THE TEMP AT
CLL WARMED FROM 66 TO 74 IN DURING THE LAST HOUR AND WINDS ARE
AGAIN OUT OF THE SOUTH. RADAR IS SHOWING GOOD COVERAGE OF LIGHT
SHOWERS...WITH GENERALLY TRACE AMOUNTS. WILL BUMP POPS TO CHANCE
OVER THE NORTHERN ZONES AS THE LATEST RUC AND NAM12 GUIDANCE SUPPORTS
AFTERNOON CONVECTION OVER THE NORTHERN ZONES ALONG THE COLD FORNT.
WILL MAINTAIN 20 POPS ELSEWHERE FOR STREAMER SHOWERS. ANY BREAKS
IN THE CLOUD COVER WILL ALLOW TEMPS TO WARM INTO THE LOWER AND
MIDDLE 80S. WILL KEEP TEMP FORECAST AS IS.
NAM 12 SHOWS MORE CAPPING OVER THE SOUTHERN HALF OF THE REGION ON
TUESDAY. GFS IS STILL ADVERTISING A GOOD SHOT OF RAIN AREAWIDE.
WILL WAIT ON THE CAN/ECMWF BEFORE CONTEMPLATING ANY CHANGES FOR
TUESDAY. 43
PREV DISCUSSION... /ISSUED 531 AM CST MON NOV 21 2011/
DISCUSSION...
UPDATED FOR 12Z TAF ISSUANCE
AVIATION...
SCATTERED SHOWERS ONGOING THIS MORNING ACROSS OUR NORTHWESTERN
COUNTIES IN THE VICINITY OF THE STATIONARY SURFACE FRONT WHICH IS
DRAPED JUST NORTH OF CLL. THIS FRONT SHOULD LIFT NORTHWARD LATER
THIS MORNING AND CIGS WILL LIFT AND SCATTER OUT TO VFR. A FEW SHOWERS
ARE POSSIBLE AGAIN TODAY BUT WILL NOT MENTION IN THE TAFS DUE TO
VERY ISOLATED NATURE. MVFR CIGS BUILD BACK IN QUICKLY AFTER SUNSET
THIS EVENING. HAVE INCLUDED MENTION OF CB FOR CLL AND IAH TUESDAY
MORNING TO ACCOUNT FOR EXPECTED SHOWER AND THUNDERSTORM ACTIVITY
AHEAD OF THE COLD FRONT WHICH WILL PUSH THROUGH THE REGION JUST
BEYOND THE CURRENT TAF PERIOD. 38
PREV DISCUSSION... /ISSUED 328 AM CST MON NOV 21 2011/
DISCUSSION...
LOW LEVEL JET CONTINUES TO TRANSPORT DEEP MOISTURE NORTH INTO SE TX
THIS MORNING. PWS ARE RUNNING AROUND 1.5 INCHES WITH SFC DEWPOINTS
IN THE LOWER 70S. COLD FRONT WAS LOCATED JUST NORTH OF THE CWA THIS
HOUR BETWEEN COLLEGE STATION AND HEARNE. THE FRONT IS EXPECTED TO
SAG SLOWLY SOUTHWARD THROUGH MID MORNING AND COULD BRIEFLY MOVE INTO
BURLESON...BRAZOS...AND MADISON COUNTIES. THE BOUNDARY WILL THEN
RETREAT BACK NORTH AS A WARM FRONT THIS AFTN. SCATTERED SHOWERS HAVE
DEVELOPED OVER THE NW ZONES DUE TO THE COMBINATION OF DEEP MOISTURE
AND CONVERGENCE ALONG THE FRONT. THIS ACTIVITY SHOULD DIMINISH BY
AFTERNOON AS THE FRONT STARTS TO RETREAT AWAY FROM THE AREA. STRONG
CAPPING IS EXPECTED TO KEEP ALL OF THE SIGNIFICANT CONVECTIVE
DEVELOPMENT NORTH OF THE AREA UNTIL LATE TONIGHT. ANOTHER
UNSEASONABLY WARM/HUMID DAY CAN BE EXPECTED TODAY WITH BREAKS IN THE
CLOUDS ALLOWING FOR NEAR RECORD HIGHS ONCE AGAIN. UPPER LOW NEAR THE
SOUTHERN CALIFORNIA COAST WILL MOVE EAST ACROSS THE SOUTHERN PLAINS
TONIGHT/TUESDAY. FRONT WILL PUSH SOUTH AGAIN AS A COLD FRONT TUESDAY
AS THE TROUGH APPROACHES. GIVEN THE PERSISTENT UPPER RIDGING OVER
THE GULF...PREFER THE SLOWER NAM SOLUTION WITH THE MOVEMENT OF THE
FRONT. THE FRONT WILL REACH THE NRN ZONES TUESDAY AFTN...HOUSTON
AREA EARLY TUESDAY EVENING...AND THE COAST LATE TUESDAY EVENING.
DEEP MOISTURE WILL POOL AHEAD OF THE FRONT WITH PWS 1.6-1.8 INCHES.
UPPER FLOW BECOMES MORE DIFFLUENT TUESDAY WITH SE TX IN THE RIGHT
REAR QUAD OF A JET MAX AT 300 MB. SPC HAS THE FAR NRN ZONES IN A
SLIGHT RISK TONIGHT...AND THE EASTERN 2/3 OF THE AREA IN A SLIGHT
RISK FOR TUESDAY. THE ATMOSPHERE WILL BE PLENTY UNSTABLE WITH LIS
AROUND -5 AND CAPES OF 1000-2000 J/KG. HOWEVER...SHEAR VALUES WILL
BE FAIRLY MARGINAL. THE 4KM NMM-WRF HAS THE BAND OF CONVECTION STILL
NW OF THE AREA AT 12Z TUESDAY...WHICH IS IN LINE WITH THE PREFERRED
SLOWER NAM SOLUTION. SO EXPECT THE BULK OF THE SHOWERS/THUNDERSTORMS
ON TUESDAY. WILL KEEP MENTION OF ISOLATED SEVERE AND LOCALLY HEAVY
RAINFALL IN THE HWOHGX. PATCHY SEA FOG HAS DEVELOPED OVER GALVESTON
BAY AND THE ADJACENT WATERS BUT VISIBILITIES HAVE MAINLY REMAINED
ABOVE 3 MILES. CURRENT THINKING IS THAT THE DENSE FOG WILL REMAIN
EAST OF THE AREA AS NOVEMBER IS CLIMATOLOGICALLY A BIT EARLY FOR
DENSE SEA FOG ALONG THE UPPER TEXAS COAST.
GRADUAL CLEARING CAN BE EXPECTED TUESDAY NIGHT AS SFC HIGH BUILDS
INTO SE TX IN THE WAKE OF THE FRONT. DRY AND PLEASANT CONDITIONS
ARE EXPECTED WEDNESDAY/THANKSGIVING DAY WITH SFC HIGH PRESSURE
RESULTING IN CLEAR SKIES AND SEASONABLE TEMPERATURES. THE UPPER
AIR PATTERN WILL REMAIN PROGRESSIVE WITH THE NEXT LONGWAVE TROUGH
APPROACHING FROM THE WEST LATE WEEK. 40 KT LOW LEVEL JET DEVELOPS
THURSDAY NIGHT/FRIDAY WHICH RESULTS IN A FAIRLY RAPID RETURN OF
MOISTURE TO THE AREA. PWS WILL REACH 1.6-1.8 INCHES AGAIN BY
FRIDAY. WILL SEE AN INCREASE IN CLOUD COVER AND WARMER/MORE HUMID
CONDITIONS THIS PERIOD. THE ATMOSPHERE BECOMES UNSTABLE ENOUGH TO
SUPPORT SCATTERED CONVECTIVE DEVELOPMENT BEGINNING FRIDAY AFTN.
ASSOCIATED COLD FRONT WILL PUSH ACROSS SE TX FRIDAY NIGHT/EARLY
SATURDAY WITH THE POSSIBILITY OF A SQUALL LINE ALONG THE FRONT.
HAVE LEANED TOWARD THE MORE PROGRESSIVE SOLUTIONS OF THE
GFS/CANADIAN/GFS ENSEMBLE MEAN WITH THE HANDLING OF THE TROUGH.
EXPECT SKIES TO CLEAR OUT SATURDAY AFTN WITH DRY/COOL WEATHER THE
REMAINDER OF THE WEEKEND.
RECORD HIGHS:
MON 11/21
CLL 85/1933
IAH 84/2007
HOU 84/2007
GLS 81/2004
RECORD HIGH MINS:
MON 11/21
CLL 67/1982
IAH 70/1909
HOU 69/2004
GLS 72/1965
35
MARINE...
WINDS AND SEAS CURRENTLY RUNNING JUST BELOW SCEC CRITERIA ACROSS THE
OFFSHORE WATERS. SCEC WILL LIKELY BE NEEDED THIS AFTERNOON AND
TONIGHT AS ONSHORE WINDS INCREASE ACROSS THE COASTAL WATERS. NEXT
COLD FRONT WILL MOVE OFFSHORE LATE TUESDAY BRINGING STRONG OFFSHORE
FLOW THROUGH MIDDAY WEDNESDAY. WINDS BECOME ONSHORE AGAIN BY LATE
THURSDAY AHEAD OF ANOTHER COLD FRONT EXPECTED TO ARRIVE NEXT
WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 69 77 47 71 48 / 40 60 10 0 0
HOUSTON (IAH) 70 81 51 71 50 / 20 60 20 0 0
GALVESTON (GLS) 71 79 56 70 56 / 20 60 30 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1031 AM CST MON NOV 21 2011
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
AT 16Z...A COLD FRONT EXTENDED SOUTH FROM LONGVIEW TO PALASTINE TO
CALDWELL. THE FRONT APPEARS TO BE RETREATING NORTH AS THE TEMP AT
CLL WARMED FROM 66 TO 74 IN DURING THE LAST HOUR AND WINDS ARE
AGAIN OUT OF THE SOUTH. RADAR IS SHOWING GOOD COVERAGE OF LIGHT
SHOWERS...WITH GENERALLY TRACE AMOUNTS. WILL BUMP POPS TO CHANCE
OVER THE NORTHERN ZONES AS THE LATEST RUC AND NAM12 GUIDANCE SUPPORTS
AFTERNOON CONVECTION OVER THE NORTHERN ZONES ALONG THE COLD FORNT.
WILL MAINTAIN 20 POPS ELSEWHERE FOR STREAMER SHOWERS. ANY BREAKS
IN THE CLOUD COVER WILL ALLOW TEMPS TO WARM INTO THE LOWER AND
MIDDLE 80S. WILL KEEP TEMP FORECAST AS IS.
NAM 12 SHOWS MORE CAPPING OVER THE SOUTHERN HALF OF THE REGION ON
TUESDAY. GFS IS STILL ADVERTISING A GOOD SHOT OF RAIN AREAWIDE.
WILL WAIT ON THE CAN/ECMWF BEFORE CONTEMPLATING ANY CHANGES FOR
TUESDAY. 43
&&
.PREV DISCUSSION... /ISSUED 531 AM CST MON NOV 21 2011/
DISCUSSION...
UPDATED FOR 12Z TAF ISSUANCE
AVIATION...
SCATTERED SHOWERS ONGOING THIS MORNING ACROSS OUR NORTHWESTERN
COUNTIES IN THE VICINITY OF THE STATIONARY SURFACE FRONT WHICH IS
DRAPED JUST NORTH OF CLL. THIS FRONT SHOULD LIFT NORTHWARD LATER
THIS MORNING AND CIGS WILL LIFT AND SCATTER OUT TO VFR. A FEW SHOWERS
ARE POSSIBLE AGAIN TODAY BUT WILL NOT MENTION IN THE TAFS DUE TO
VERY ISOLATED NATURE. MVFR CIGS BUILD BACK IN QUICKLY AFTER SUNSET
THIS EVENING. HAVE INCLUDED MENTION OF CB FOR CLL AND IAH TUESDAY
MORNING TO ACCOUNT FOR EXPECTED SHOWER AND THUNDERSTORM ACTIVITY
AHEAD OF THE COLD FRONT WHICH WILL PUSH THROUGH THE REGION JUST
BEYOND THE CURRENT TAF PERIOD. 38
PREV DISCUSSION... /ISSUED 328 AM CST MON NOV 21 2011/
DISCUSSION...
LOW LEVEL JET CONTINUES TO TRANSPORT DEEP MOISTURE NORTH INTO SE TX
THIS MORNING. PWS ARE RUNNING AROUND 1.5 INCHES WITH SFC DEWPOINTS
IN THE LOWER 70S. COLD FRONT WAS LOCATED JUST NORTH OF THE CWA THIS
HOUR BETWEEN COLLEGE STATION AND HEARNE. THE FRONT IS EXPECTED TO
SAG SLOWLY SOUTHWARD THROUGH MID MORNING AND COULD BRIEFLY MOVE INTO
BURLESON...BRAZOS...AND MADISON COUNTIES. THE BOUNDARY WILL THEN
RETREAT BACK NORTH AS A WARM FRONT THIS AFTN. SCATTERED SHOWERS HAVE
DEVELOPED OVER THE NW ZONES DUE TO THE COMBINATION OF DEEP MOISTURE
AND CONVERGENCE ALONG THE FRONT. THIS ACTIVITY SHOULD DIMINISH BY
AFTERNOON AS THE FRONT STARTS TO RETREAT AWAY FROM THE AREA. STRONG
CAPPING IS EXPECTED TO KEEP ALL OF THE SIGNIFICANT CONVECTIVE
DEVELOPMENT NORTH OF THE AREA UNTIL LATE TONIGHT. ANOTHER
UNSEASONABLY WARM/HUMID DAY CAN BE EXPECTED TODAY WITH BREAKS IN THE
CLOUDS ALLOWING FOR NEAR RECORD HIGHS ONCE AGAIN. UPPER LOW NEAR THE
SOUTHERN CALIFORNIA COAST WILL MOVE EAST ACROSS THE SOUTHERN PLAINS
TONIGHT/TUESDAY. FRONT WILL PUSH SOUTH AGAIN AS A COLD FRONT TUESDAY
AS THE TROUGH APPROACHES. GIVEN THE PERSISTENT UPPER RIDGING OVER
THE GULF...PREFER THE SLOWER NAM SOLUTION WITH THE MOVEMENT OF THE
FRONT. THE FRONT WILL REACH THE NRN ZONES TUESDAY AFTN...HOUSTON
AREA EARLY TUESDAY EVENING...AND THE COAST LATE TUESDAY EVENING.
DEEP MOISTURE WILL POOL AHEAD OF THE FRONT WITH PWS 1.6-1.8 INCHES.
UPPER FLOW BECOMES MORE DIFFLUENT TUESDAY WITH SE TX IN THE RIGHT
REAR QUAD OF A JET MAX AT 300 MB. SPC HAS THE FAR NRN ZONES IN A
SLIGHT RISK TONIGHT...AND THE EASTERN 2/3 OF THE AREA IN A SLIGHT
RISK FOR TUESDAY. THE ATMOSPHERE WILL BE PLENTY UNSTABLE WITH LIS
AROUND -5 AND CAPES OF 1000-2000 J/KG. HOWEVER...SHEAR VALUES WILL
BE FAIRLY MARGINAL. THE 4KM NMM-WRF HAS THE BAND OF CONVECTION STILL
NW OF THE AREA AT 12Z TUESDAY...WHICH IS IN LINE WITH THE PREFERRED
SLOWER NAM SOLUTION. SO EXPECT THE BULK OF THE SHOWERS/THUNDERSTORMS
ON TUESDAY. WILL KEEP MENTION OF ISOLATED SEVERE AND LOCALLY HEAVY
RAINFALL IN THE HWOHGX. PATCHY SEA FOG HAS DEVELOPED OVER GALVESTON
BAY AND THE ADJACENT WATERS BUT VISIBILITIES HAVE MAINLY REMAINED
ABOVE 3 MILES. CURRENT THINKING IS THAT THE DENSE FOG WILL REMAIN
EAST OF THE AREA AS NOVEMBER IS CLIMATOLOGICALLY A BIT EARLY FOR
DENSE SEA FOG ALONG THE UPPER TEXAS COAST.
GRADUAL CLEARING CAN BE EXPECTED TUESDAY NIGHT AS SFC HIGH BUILDS
INTO SE TX IN THE WAKE OF THE FRONT. DRY AND PLEASANT CONDITIONS
ARE EXPECTED WEDNESDAY/THANKSGIVING DAY WITH SFC HIGH PRESSURE
RESULTING IN CLEAR SKIES AND SEASONABLE TEMPERATURES. THE UPPER
AIR PATTERN WILL REMAIN PROGRESSIVE WITH THE NEXT LONGWAVE TROUGH
APPROACHING FROM THE WEST LATE WEEK. 40 KT LOW LEVEL JET DEVELOPS
THURSDAY NIGHT/FRIDAY WHICH RESULTS IN A FAIRLY RAPID RETURN OF
MOISTURE TO THE AREA. PWS WILL REACH 1.6-1.8 INCHES AGAIN BY
FRIDAY. WILL SEE AN INCREASE IN CLOUD COVER AND WARMER/MORE HUMID
CONDITIONS THIS PERIOD. THE ATMOSPHERE BECOMES UNSTABLE ENOUGH TO
SUPPORT SCATTERED CONVECTIVE DEVELOPMENT BEGINNING FRIDAY AFTN.
ASSOCIATED COLD FRONT WILL PUSH ACROSS SE TX FRIDAY NIGHT/EARLY
SATURDAY WITH THE POSSIBILITY OF A SQUALL LINE ALONG THE FRONT.
HAVE LEANED TOWARD THE MORE PROGRESSIVE SOLUTIONS OF THE
GFS/CANADIAN/GFS ENSEMBLE MEAN WITH THE HANDLING OF THE TROUGH.
EXPECT SKIES TO CLEAR OUT SATURDAY AFTN WITH DRY/COOL WEATHER THE
REMAINDER OF THE WEEKEND.
RECORD HIGHS:
MON 11/21
CLL 85/1933
IAH 84/2007
HOU 84/2007
GLS 81/2004
RECORD HIGH MINS:
MON 11/21
CLL 67/1982
IAH 70/1909
HOU 69/2004
GLS 72/1965
35
MARINE...
WINDS AND SEAS CURRENTLY RUNNING JUST BELOW SCEC CRITERIA ACROSS THE
OFFSHORE WATERS. SCEC WILL LIKELY BE NEEDED THIS AFTERNOON AND
TONIGHT AS ONSHORE WINDS INCREASE ACROSS THE COASTAL WATERS. NEXT
COLD FRONT WILL MOVE OFFSHORE LATE TUESDAY BRINGING STRONG OFFSHORE
FLOW THROUGH MIDDAY WEDNESDAY. WINDS BECOME ONSHORE AGAIN BY LATE
THURSDAY AHEAD OF ANOTHER COLD FRONT EXPECTED TO ARRIVE NEXT
WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 86 69 77 47 71 / 30 40 60 10 0
HOUSTON (IAH) 83 70 81 51 71 / 20 20 60 20 0
GALVESTON (GLS) 77 71 79 56 70 / 10 20 60 30 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43