Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/13/11
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1001 PM MST SAT DEC 10 2011
.AVIATION...
LIGHT WINDS AND VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 H
OVR ALL OF SE CO. AS MENTIONED IN THE PREVIOUS AFD...THERE IS A
SLIGHT CHANCE THAT SOME LOCALIZED AND BRIEF PC FG COULD DEVELOP
IN THE SAN LUIS VALLEY SUN MORNING...BUT THE PROBABILITY IS TOO
LOW TO MENTION IN THE TAF FOR KALS. ANY FG OR BR SHOULD DISSIPATE
QUICKLY AFTER SUNRISE. ROSE
&&
.PREV DISCUSSION... /ISSUED 306 PM MST SAT DEC 10 2011/
SHORT TERM...
(TONIGHT AND SUNDAY)
WE WILL CONTINUE TO SEE CLEAR SKIES TONIGHT. THE FLOW ALOFT TONIGHT
IS EXPECTED TO BECOME MORE WESTERLY WITH A LEE SFC TROF DEVELOPING.
THE WESTERLY WINDS NEAR THE MTS SHOULD KEEP TEMPS A BIT WARMER THAN
THEY WERE LAST NIGHT. TEMPS OVR THE SERN PLAINS WL ALSO BE A LITTLE
WARMER MOST AREAS. THE SAN LUIS VALLEY HOWEVER SHOULD STILL SEE
SINGLE DIGITS ABOVE AND BELOW ZERO FOR LOW TEMPS TONIGHT. THE NAM
BUFKIT SOUNDING FOR KALS SHOWS THE POTENTIAL FOR STRATUS AND FOG
DEVELOPING. WE DIDN`T SEE THAT HAPPEN THIS MORNING AND I HAVE LOW
CONFIDENCE THAT IT WILL HAPPEN TONIGHT. THE RUC AND NAM SOUNDINGS
FOR KLHX AND KLAA ALSO SHOW THE POTENTIAL FOR STRATUS/FOG DEVELOPING
AGAIN. I AM NOT REAL CONFIDENT IN THIS EITHER. SO FOR NOW WL LEAVE
OUT THE MENTION OF CLOUDS AND/OR FOG.
ANOTHER DRY DAY IS EXPECTED SUNDAY WITH BEING A LITTLE WARMER THAN
TODAY IN MOST AREAS...ALTHOUGH THE SAN LUIS VALLEY MAY SEE SIMILAR
OR JUST SLIGHTLY WARMER TEMPS THAN TODAY. THE NAM IS SHOWING LOW
LEVEL MOISTURE WORKING ITS WAY NORTHWARD SUNDAY AFTERNOON...AND INTO
THE FAR SERN CORNER OF THE STATE (MOSTLY BACA COUNTY)...SO WE WL
PROBABLY SEE AN INCREASE IN CLOUDS OVR THAT AREA.
LONG TERM...
(SUNDAY NIGHT THROUGH SATURDAY)
METEOROLOGICAL ISSUES THIS LONGER TERM CYCLE INCLUDE BUT ARE NOT
LIMITED TO POPS...POTENTIAL SNOW AMOUNTS(ESPECIALLY OVER SECTIONS
OF THE CENTRAL AND SOUTHWESTERN MOUNTAINS)...GUSTY WINDS AT TIMES
AND TEMPERATURES.
RECENT LONGER TERM MODEL SOLUTIONS SUGGEST THAT THE DRY SOUTHWEST
UPPER FLOW OF SUNDAY NIGHT INTO AT LEAST EARLY MONDAY AFTERNOON
WILL GIVE WAY TO INCREASING PRECIPITATION CHANCES(AS CLOSED UPPER
LOW DEVELOPS OVER FAR SOUTHERN CALIFORNIA BY 06Z TUESDAY AND THEN
MOVES INTO THE 4-CORNERS REGION BY TUESDAY NIGHT) FROM LATER
MONDAY AFTERNOON INTO AT LEAST TUESDAY EVENING(ESPECIALLY OVER
ZONE 68/EASTERN SAN JUAN MOUNTAINS WHERE LATEST MODEL PROJECTIONS
INDICATE THAT SNOW AMOUNTS IN EXCESS OF 12 INCHES MAY OCCUR FROM
MONDAY NIGHT INTO TUESDAY...I.E. MY 5TH AND 6TH PERIODS).
AT THIS TIME...WILL HOLD OFF ON ANY WINTER HIGHLIGHTS FOR NOW SINCE
EVENT IS STILL A BIT TOO FAR OUT IN TIME...HOWEVER IF LATEST
COMPUTER MODEL TRENDS PERSIST...WFO PUEBLO WILL LIKELY BE ISSUING
WINTER WEATHER HIGHLIGHTS...ESPECIALLY FOR AREAS SUCH AS ZONE 68
DURING THE NEXT DAY OR TWO...PLEASE STAY TUNED.
ELSEWHERE...AS INITIAL UPPER SYSTEM PUSHES ACROSS THE REGION FROM
TUESDAY NIGHT INTO WEDNESDAY...ANTICIPATE INCREASED CLOUD/SHOWER
ACTIVITY IN COMBINATION WITH COOLER TEMPERATURES.
FORECAST DISTRICT THEN RECEIVES A BRIEF RESPITE THURSDAY BEFORE NEXT
CLOSED LOW TRAVELS FROM THE PACIFIC NORTHWEST ON THURSDAY AND
SETTLES OVER FAR SOUTHERN CALIFORNIA FROM FRIDAY EVENING INTO
SATURDAY.
THIS NEXT UPPER SYSTEM SHOULD AGAIN IMPACT WESTERN AND NORTHERN
PORTIONS OF THE CWFA WITH UNSETTLED CONDITIONS FROM LATER THURSDAY
INTO AT LEAST FRIDAY...ALTHOUGH PRIMARY PRECIPITATION FOCUS WITH
THIS SYSTEM APPEARS TO REMAIN WELL SOUTH THROUGH SOUTHWEST OF THE
CWFA DURING THIS TIME-FRAME.
IN ADDITION...TEMPERATURES GENERALLY RUNNING NEAR OR BELOW MID-DECEMBER
SEASONAL AVERAGES ARE ANTICIPATED DURING THE LONGER TERM.
FINALLY...GUSTY WINDS WILL BE POSSIBLE AT TIMES FROM TUESDAY INTO
TUESDAY NIGHT AND THEN AGAIN BY NEXT FRIDAY(ESPECIALLY EASTERN
SECTIONS).
AVIATION...
EXPECT VFR CONDITIONS FOR THE NEXT 24 HOURS AT KCOS AND KPUB. KALS
WL LIKELY HAVE VFR CONDITIONS DURING THIS PERIOD AS WELL...HOWEVER
ONE MODEL SOUNDING IS SHOWING THE POTENTIAL FOR THE DEVELOPMENT OF
STRATUS/FOG TONIGHT. SINCE IT DIDN`T HAPPEN THIS MORNING AND THE
MODEL HAD FORECAST IT YESTERDAY...MY CONFIDENCE IN THE STATUS/FOG
DEVELOPING IS LOW AND WL LEAVE IT OUT OF THE TAF.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44/10
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
951 PM EST MON DEC 12 2011
.SYNOPSIS...
SURFACE HIGH PRESSURE CENTERED NORTH OF THE AREA WILL PERSIST
THROUGH MID WEEK BEFORE WEAKENING AND SHIFTING OFFSHORE LATE IN
THE WEEK. A COLD FRONT COULD STALL OVER OR NEAR THE REGION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
DRY CONDITIONS ARE EXPECTED OVERNIGHT AS HIGH PRESSURE HOLDS FIRM
ACROSS MUCH OF THE SOUTHEAST UNITED STATES. HAVE MADE SOME FAIRLY
SIZABLE CHANGES TO THE GRIDS AND TEXT PRODUCTS FOR THE OVERNIGHT
PERIOD AS SHORTER TERM TRENDS ARE FINALLY BECOMING MORE APPARENT.
CONFIDENCE IS INCREASING THAT THE POTENTIAL FOR A WIDESPREAD
STRATUS/FOG EVENT IS DIMINISHING WITH TIME AS THE LOWER
TROPOSPHERE CONTINUES TO DRY OUT. 13/01Z RUC SOUNDINGS SUGGEST AN
ENHANCED BOUNDARY LAYER WIND FIELD WILL LIKELY SEVERELY CURTAIL
THE FOG POTENTIAL AND ALTHOUGH PATCHES OF STRATUS ARE LIKELY TO
REFORM PRIOR TO DAYBREAK...SUSPECT THE THICKEST STRATUS DECK WILL
REMAIN SOUTH OF THE ALTAMAHA RIVER. WILL GO WITH A GENERAL PARTLY
CLOUDY SKY FORECAST THROUGH SUNRISE FOR THIS REASON...ALTHOUGH
THERE WILL BE SOME FAIRLY SIZABLE CLEAR PERIODS THIS EVENING.
LOWS FROM THE UPPER 30S WELL INLAND TO THE MID 40S AT THE COAST
LOOK ON TRACK.
WE GREATLY APPRECIATE ALL OF THE FOG REPORTS THAT WERE RELAYED IN
NWSCHAT BY THE LOCAL SAVANNAH MEDIA THIS EVENING.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
PRETTY GOOD MODEL AGREEMENT FOR MID WEEK WITH SURFACE HIGH PRESSURE
CENTERED NORTH OF THE AREA SLOWLY SHIFTING EAST INTO THE ATLANTIC.
MEANWHILE...HIGH PRESSURE ALOFT WILL BECOME STRONGER THROUGH
WEDNESDAY BEFORE WEAKENING THURSDAY AS A COLD FRONT BEGINS TO
APPROACH FROM THE WEST. EXPECT A DRY PERIOD WITH THE LACK OF DEEP
MOISTURE. TEMPERATURES WILL BE ON A SLOW WARMING TREND...REACHING
WELL ABOVE NORMAL LEVELS THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE UPPER LEVEL PATTERN WILL BECOME ZONAL LATE IN THE WEEK...ALLOWING
A BACKDOOR COLD FRONT TO SLOWLY SINK SOUTH INTO THE AREA OVER THE
WEEKEND. GUIDANCE REMAINS IN DISAGREEMENT AS TO WHEN THE FRONT
WILL PUSH THROUGH THE AREA SO HAVE MADE NO CHANGES TO THIS PORTION
OF THE FORECAST WHICH CURRENTLY HAS SLIGHT RAIN CHANCES FRIDAY
NIGHT THROUGH SATURDAY NIGHT. UPPER LEVEL HIGH PRESSURE WILL THEN
RETURN BRIEFLY EARLY NEXT WEEK BEFORE THE NEXT STORM SYSTEM BEGINS
TO APPROACH FROM THE WEST. TEMPERATURES GENERALLY ABOVE NORMAL
THROUGH THE PERIOD...EVEN BEHIND THE COLD FRONT.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AT KCHS...VFR CIGS/VSBYS WILL PREVAIL THROUGH 09Z TONIGHT. DESPITE A
GRADUAL DRYING TREND ALOFT...IFR CONDITIONS WILL BE POSSIBLE BETWEEN
09-12Z AS LOW LVL MOISTURE REMAINS TRAPPED BELOW AN INVERSION. LOW
LVL WINDS BETWEEN 15-20 KTS WILL LIKELY KEEP THE MAIN THREAT TO AN
IFR STRATUS EVENT...BUT MVFR VSBYS WILL REMAIN POSSIBLE AS WELL
UNTIL DAYBREAK. VFR CONDITIONS SHOULD RETURN AS LOW LEVELS DRY BY
14-15Z TUESDAY.
AT KSAV...THERE MAY BE A PERIOD OF VFR CONDITIONS BETWEEN 00-04Z
EARLY TONIGHT AS SUBTLE DRYING OCCURS ALOFT...BUT CONDITIONS WILL
LIKELY BE SHORT LIVED...AND REMAIN IN IFR CONDITIONS AS LOW LVL MOISTURE
REMAINS ABUNDANT OVER THE TERMINAL. EXPECT IFR CONDITIONS TO PERSIST
UNTIL DAYBREAK WITH PERIODS OF MVFR VSBYS THROUGH TUESDAY MORNING.
CONDITIONS WILL THEN QUICKLY IMPROVE TO VFR BY 15Z AND REMAIN THAT
WAY THROUGH THE REMAINDER OF THE DAY.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS POSSIBLE
EARLY TUESDAY MORNING IN AREAS OF STRATUS AND/OR FOG.
&&
.MARINE...
BUOY AND PILOT BOAT REPORTS INDICATE SEAS HAVE DROPPED BELOW 6 FT
ACROSS THE SOUTH CAROLINA LEGS SO THE SMALL CRAFT ADVISORY HAS
BEEN CANCELLED FOR AMZ350-352. LOOKS LIKE MARGINAL 6 FT SEAS WILL
CONTINUE FOR SEVERAL MORE HOURS OVER THE GEORGIA NEARSHORE WATERS
WHERE FLAGS REMAIN IN FORCE UNTIL 5 AM TUESDAY. SOLID SMALL CRAFT
ADVISORY CONDITIONS WILL PERSIST OVER THE GEORGIA OFFSHORE WATERS
THROUGH THE NIGHT.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL REMAIN CENTERED NORTH
OF THE WATERS THROUGH WEDNESDAY BEFORE SHIFTING EAST ON THURSDAY. A
COLD FRONT WILL THEN APPROACH LATE IN THE WEEK BEFORE EVENTUALLY
PUSHING THROUGH THE AREA OVER THE WEEKEND. EXPECT WINDS TO DECREASE
SIGNIFICANTLY TUESDAY AS THE HIGH WEAKENS. SEAS WILL SLOWLY SUBSIDE
ALONG WITH THE WINDS WITH ADVISORY CONDITIONS PERSISTING BEYOND 20
NM THROUGH WEDNESDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR AMZ354.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1223 AM CST SUN DEC 11 2011
.AVIATION...
CONCERN WILL BE WITH LOW CLOUDS AND CIGS. STRATUS CONTINUES TO
MOVE NEWD INTO SOUTHEAST NE AND APPROACHING NW MO. LOW LEVEL
WARM... MOIST ADVECTION NEXT 24 HOURS ON BACKSIDE OF DEPARTING
SFC RIDGE SUPPORTIVE OF LOW CLOUDS MOVING AND/OR DEVELOPING
ACROSS REGION. HRRR AND RUC BACKUP MODELS ONLY ONES THAT HAVE
HANDLE ON STRATUS... THUS LEANED HEAVILY TOWARD FOR 06Z TAFS.
PRESSURE FALLS SHOWING UP ACROSS NORTHEAST IA AND STRATUS ALSO
OVER NORTHERN WI HAS BEEN DEVELOPING SOME TO SW... AND WILL
NEED TO WATCH FOR THIS TO CONTINUE OVRNGT THAT COULD BRING SOME
LOW CLOUDS VCNTY OF KDBQ TOWARD DAYBREAK. OTHERWISE... FOLLOWED
HRRR AND RUC BACKUP TIMING OF MID AM THROUGH MIDDAY ON LOW CLOUDS
INTO TERMINALS WITH IFR CIGS AND JUST LEFT IN FOR DURATION OF
FCST THROUGH SUN EVE. HAVE TO WATCH FOR SOME LIFTING DUE TO DIURNAL
EFFECTS... AND ALSO CONCERNS WITH SOME EROSION OF DECK WITH
MIXING. SOME LIGHT FOG EXPECTED AS WELL WITH VSBYS GENERALLY
2-6SM. WINDS GENERALLY S/SE TNGT AROUND 10 KTS. SOME LLWS POSSIBLE
VCNTY OF KDBQ WHERE 925 MB WINDS ON BLUE RIVER PROFILER AT 40 KTS.
MODELS SUGGEST THE CORE OF STRONGER WINDS 950-925 MB TO PUSH INTO
WI NEXT FEW HRS AND SO HAVE NOT PUT IN LLWS FOR KDBQ ATTIM. WINDS
WILL BE FROM S/SW AT 11-18 KTS WITH SOME GUSTS IN L20 KTS POSSIBLE
DURING AFTN.
&&
.PREV DISCUSSION... /ISSUED 257 PM CST SAT DEC 10 2011/
SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE AT THE SURFACE EXTENDED FROM THE
SOUTHERN PLAINS THROUGH THE OHIO VALLEY. LOW PRESSURE WAS LOCATED OVER
SOUTHWESTERN CANADA...AHEAD OF A MID LEVEL TROF JUST OF THE
BRITISH COLUMBIA COAST. DOWNSTREAM FROM THE TROF...BROAD MID LEVEL
RIDGING COVERED THE ROCKY MOUNTAINS WITH A BROAD TROF CENTERED
NEAR THE ATLANTIC COAST.
SHORT TERM...TONIGHT THROUGH MONDAY...
FOR TONIGHT AND SUNDAY SKY TRENDS AND TEMPERATURES WILL BE THE
MAIN CONCERN WITH A DRY WAA REGIME DEVELOPING OVER THE CENTRAL U.S.
TONIGHT...STRATUS OVER THE CWFA LATE THIS AFTERNOON WILL CONTINUE
MOVING EAST WITH CLEAR SKIES EXPECTED OVER THE AREA BY LATE THIS
EVENING. AREAS EAST OF THE RIVER WILL STILL BE IMPACTED BY THE
LIGHT FLOW NEAR THE OHIO VALLEY SURFACE RIDGE...BUT SHOULD HAVE CLOUD
COVER FOR AT LEAST A COUPLE OF HOURS AFTER SUNSET. THIS SHOULD
PREVENT TEMPERATURES FROM CRASHING THIS EVENING. BY THE TIME THE
CLOUDS MOVE OUT THE GRADIENT SHOULD BE STRONG ENOUGH TO KEEP SOME
MIXING GOING...SO RAISED OVERNIGHT LOWS A COUPLE OF DEGREES. TO
THE WEST SKIES SHOULD BE CLEAR MUCH OF THE NIGHT AND HAVE RELIED
ON MIXING TO KEEP TEMPERATURES FROM BOTTOMING OUT. THERE IS ALSO
SOME CONCERN THAT THE STRATUS OVER SOUTHERN PLAINS WILL START TO
SPREAD NE AFTER SUNSET. HAVE YET TO FIND ANY MODEL DATA TO SUPPORT
THIS...BUT ON THE OTHER HAND...THE 12Z RUNS WERE NOT CAPTURING THE
SHALLOW MOISTURE OVER THE SOUTHERN PLAINS. WITH THE HIGH DEGREE OF
UNCERTAINTY CONCERNING THESE CLOUDS WILL KEEP OUT OF THE FORECAST
FOR NOW. PROVIDED THE STRATUS THREAT DOES NOT MATERIALIZE
TONIGHT...THE LOW LEVEL WAA SUNDAY ALONG WITH MOSTLY SUNNY SKIES
SHOULD PUSH TEMPERATURES INTO THE 30S WITH LOW 40S POSSIBLE IN THE
SOUTH.
SUNDAY NIGHT AND MONDAY LOW LEVEL MOISTURE WILL BE INCREASING IN
THE SOUTHWEST FLOW AHEAD OF A COLD FRONT MOVING INTO WESTERN IOWA
BY MONDAY MORNING. THERE IS SOME POTENTIAL FOR DRIZZLE OR FREEZING
DRIZZLE LATE SUNDAY NIGHT IN THE WEST. MONDAY WITH THE ATMOSPHERE
PROGGED TO SATURATE TO AROUND 700MB AND A S/W MOVING THROUGH THE
REGION....INCLUDED A MENTION OF LIGHT RAIN ALONG WITH DRIZZLE. BY
12Z MONDAY SURFACE TEMPERATURES SHOULD BE WARM ENOUGH TO DROP THE
MENTION OF FREEZING PRECIPITATION. ..DLF..
LONG TERM...MONDAY NIGHT THROUGH NEXT SATURDAY...
MONDAY NIGHT AND TUESDAY...THE ECMWF/GFS/DGEX ARE SIMILAR IN
FLATTENING OUT AND MOVING AN UPPER LEVEL SHORTWAVE EAST TO THE GREAT
LAKES ON TUESDAY. THIS WAVE COULD PRODUCE DRIZZLE OR POSSIBLY
FREEZING DRIZZLE ACROSS NORTHWEST SECTIONS OF THE FORECAST AREA
MONDAY NIGHT AND BEFORE ENDING TUESDAY MORNING.
WEDNESDAY AND THURSDAY...MID/LONG RANGE MODELS PROG A CLOSED LOW NOW
ANCHORED OVER THE BAJA PENINSULA TO FILL AND BE KICKED TO THE
NORTHWEST AS A FAIRLY STRONG LONG WAVE TROF. THIS WAVE WILL BEGIN
SPREADING RAIN OVER THE FORECAST AREA TUESDAY NIGHT WHICH WILL
CONTINUE TROUGH THURSDAY. THERMAL PROFILES SHOW THE PRECIPITATION
MAY BEGIN AS A RAIN SNOW MIX WEDNESDAY MORNING...PRIMARILY IN
LOCATIONS NORTH OF INTERSTATE 80...BEFORE CHANGING TO ALL RAIN AS
STRONG WARM AIR ADVECTION AHEAD OF THE SYSTEM RAISES SURFACE
TEMPERATURES INTO THE MID 40S. WET SNOW MAY ALSO MIX IN WITH THE
RAIN BEFORE THE PRECIPITATION ENDS ON THURSDAY NIGHT AS COLDER AIR
WRAPS AROUND THE BACKSIDE OF THE DEPARTING LOW.
FRIDAY AND SATURDAY...LONG RANGE MODELS FORECAST BOTH DAYS TO BE DRY
AS A SHORTWAVE RIDGE ALOFT AND SURFACE HIGH PRESSURE BUILD ACROSS
THE UPPER MIDWEST. DAYTIME TEMPERATURES WILL BE THE 20S WITH
OVERNIGHT LOWS IN THE TEENS. ..KUHL..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
725 PM CST MON DEC 12 2011
.UPDATE...
THE LATEST 00 UTC KDDC SOUNDING IS INDICATING A NEARLY SATURATED
LAYER FROM NEAR THE SURFACE TO 5,000FT, ASSOCIATED WITH THE STRATUS
ACROSS THE AREA THIS EVENING. ABOVE THAT IS A TREMENDOUSLY DRY AND
DEEP LAYER FROM AROUND 875 MB THROUGH THE MIDDLE TROPOSPHERE. THE
KDDC RADAR ECHOES THAT HAVE BEEN MOVING ACROSS THE WESTERN AND
SOUTHWEST COUNTIES THIS EVENING ARE PRIMARILY ELEVATED ECHOS WITH NO
PRECIPITATION. WE`VE REMOVED POPS AND RAIN SHOWERS/DRIZZLE
ALTOGETHER FOR THIS EVENING, AND RAMPED UP POPS ACROSS THE
SOUTHEAST 1/2 OF THE FORECAST AREA AFTER MIDNIGHT TO CLOSER FOLLOW
THE HOURLY RAPID REFRESH RUC MODEL. ADDITIONALLY, AREAS OF FOG HAVE
BEEN INTRODUCED ON A WIDER SCALE GIVEN THE CURRENT NAM AND HRRR`S
VSBYS AND TRENDS WITHING THE SURFACE MOISTURE CONVERGENCE ZONE. -RUSSELL
&&
.PREV DISCUSSION... /ISSUED 602 PM CST MON DEC 12 2011/
UPDATE...
AVIATION /FOR THE 00Z TAF ISSUANCE/
VISIBILITIES AND CEILINGS WILL AGAIN BE A TREMENDOUS CHALLENGE TO
FORECAST THIS EVENING AND INTO TUESDAY. WARM AND MOIST ADVECTION IN
THE BOUNDARY LAYER ON THE NOSE OF SOUTHERLY WINDS WILL BE ON THE
INCREASE THROUGH THE PERIOD. A SIGNIFICANT DIFFERENCE EXISTS BETWEEN
NAM AND HRRR MODELS WITH RESPECT TO VISIBILITY OVERNIGHT. THE HRRR
IS A MUCH MORE AGGRESSIVE DEVELOPING DENSE FOG THAN IS THE NAM.
CURRENT THINKING IS THAT THE HRRR MAY BE MORE CORRECT SINCE
MOISTURE CONVERGENCE WOULD FAVOR MORE WIDESPREAD LOW VISIBILITIES
THAN THE VERY SHARP CUTOFF OF THE NAM, AND WE`LL HEDGE THE
FORECAST CLOSER TO THE RAPID REFRESH ESPECIALLY CONSIDERING THE
LOWERED VISBY`S OFFERED BY THE GFS LAMP PRODUCTS. CEILINGS WILL
REMAIN IN THE IFR CATEGORY OR LOWER THROUGH THE ENTIRE NIGHT. -RUSSELL
PREV DISCUSSION... /ISSUED 319 PM CST MON DEC 12 2011/
DISCUSSION...
DAYS 1-2...
THE UPPER LEVEL LOW CURRENTLY ACROSS SOUTHERN CALIFORNIA WILL START
TO EJECT EAST NORTHEAST ACROSS THE FOUR CORNERS REGION TOMORROW AND
ACROSS THE CENTRAL PLAINS BY THURSDAY MORNING. A STRONG UPPER LEVEL
JET WILL ACCOMPANY THIS SYSTEM ENHANCING LIFT ACROSS OUR CWA TONIGHT
INTO WEDNESDAY MORNING. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
BE FOUND ACROSS THE EASTERN THIRD OF THE UNITED STATES. AT THE
SURFACE...AN AREA OF HIGH PRESSURE WILL BE FOUND ACROSS THE GULF OF
MEXICO AND CONTINUE TO BRING LOWER TO MID LEVEL MOISTURE NORTH INTO
OUR AREA. A SURFACE COLD FRONT IS ANTICIPATED TO CONTINUE TO MOVE
SOUTH ACROSS KANSAS THIS AFTERNOON AND STALL OUT ACROSS OUR CWA THIS
EVENING. THIS FRONTAL BOUNDARY WILL THEN MOVE NORTHWARD OVERNIGHT
AND BE POSITIONED ACROSS THE KS/NE BORDER BY TOMORROW MORNING. RAIN
CHANCES INCREASE OVERNIGHT AND LIGHT RAIN IS POSSIBLE ACROSS
SOUTHEAST PORTIONS OF THE CWA BY MIDNIGHT SPREADING ACROSS THE
REMAINDER OF THE CWA BY TOMORROW MORNING. PATCHY FOG IS ALSO
POSSIBLE OVERNIGHT BUT SHOULD DISSIPATE BY MORNING. LAST, THERE
COULD BE A FEW AREAS THAT EXPERIENCE LIGHT FREEZING RAIN ACROSS
HAMILTON, KEARNY, SCOTT, AND TREGO COUNTIES AFTER MIDNIGHT BUT NO
ACCUMULATION OF ICE IS EXPECTED AS SURFACE TEMPERATURES WILL BE
ABOVE FREEZING.
MOISTURE CONTINUES TO ADVECT NORTHWARD ACROSS THE AREA TOMORROW
AHEAD OF THE UPPER LEVEL TROUGH ALLOWING CLOUDY SKIES AND RAIN
CHANCES TO CONTINUE THROUGHOUT THE DAY. RAIN CHANCES RANGE FROM 50
PERCENT IN THE WEST TO OVER 70 PERCENT IN THE EAST. AN AREA OF LOW
PRESSURE IS EXPECTED TO MOVE FROM NORTHEASTERN NEW MEXICO TOMORROW
AFTERNOON AND SHIFT EAST INTO SOUTHEAST NEBRASKA BY WEDNESDAY
AFTERNOON. THIS WILL PUSH A COLD FRONT THROUGH THE AREA TOMORROW
NIGHT INTO WEDNESDAY MORNING. I HAVE KEPT IN THE WORDING OF ISOLATED
THUNDER ACROSS EASTERN PORTIONS OF THE CWA TOMORROW NIGHT ENDING IN
THE LATE MORNING AS THE COLD FRONT MOVES INTO WICHITA`S WFO. POPS
DECREASE FROM WEST TO EAST TOMORROW NIGHT INTO WEDNESDAY AND BELOW
15 PERCENT ACROSS THE ENTIRE CWA BY WEDNESDAY AFTERNOON. CLOUDS WILL
ALSO BE ON THE DECREASE AS THE SYSTEM EXITS OFF TO THE EAST LEAVING
PARTLY CLOUDY SKIES BY WEDNESDAY EVENING.
LOWS TONIGHT WILL RANGE FROM THE LOWER 30S IN THE NORTHWEST TO LOWER
40S IN THE SOUTHEAST WITH HIGHS TOMORROW WILL RISING INTO THE MID TO
UPPER 40S. OVERNIGHT LOWS TOMORROW NIGHT COULD ACTUALLY CLIMB ABOVE
TUESDAYS HIGHS DEPENDING ON DEWPOINTS. I WILL CONTINUE NEARLY STEADY
TEMPERATURES IN THE 40S OVERNIGHT WITH TH EXCEPTION OF NORTHEAST
PORTIONS OF THE CWA WHERE LOWS COULD DROP INTO THE UPPER 30S. HIGHS
ON WEDNESDAY ARE ANTICIPATED TO RANGE FROM THE LOWER 50S IN THE
NORTHWEST TO NEAR 60 IN THE SOUTHEAST.
DAYS 3-7...
THE MEDIUM RANGE MODELS SHOW A SECONDARY SHORTWAVE TROUGH LIFTING
OUT OF THE DESERT SOUTHWEST AND NORTHERN MEXICO ACROSS THE SOUTHERN
PLAINS LATER THIS WEEK. THE ENERGY WITH THIS WAVE IS PRETTY FAR
SOUTH AND WITH ALL THE BEST LOW LEVEL MOISTURE BEING SHUNTED SOUTH
BY THE MIDWEEK SYSTEM...THE DRY FORECAST LOOKS GOOD. THE MODELS SHOW
ANOTHER ANTICYCLONIC WAVE BREAK OCCURRING LATE THURSDAY AND THURSDAY
NIGHT. A SHORTWAVE TROUGH NOW SOUTHWEST OF THE ALEUTIAN ISLANDS IS
FORECAST TO TOP THE EASTERN PACIFIC RIDGE AND DIG SOUTH ACROSS THE
WESTERN STATES. THE ECMWF AND CANADIAN MODELS HAVE BEEN FAIRLY
CONSISTENT WITH THE TRACK AND TIMING OF THIS SYSTEM AS IT CLOSES OFF
AND HANGS BACK IN THE SOUTHWEST BEFORE LIFTING OUT TOWARD THE
CENTRAL/SOUTHERN PLAINS LATE NEXT WEEKEND. THE GFS HAS TENDED TO BE
MORE PROGRESSIVE AS IT TENDS TO DO. YESTERDAYS GFS ENSEMBLE MEMBERS
WERE MOSTLY SLOWER THAN THE OPERATIONAL RUN. TODAYS GFS ENSEMBLE
MEMBERS WERE STILL A LITTLE SCATTERED BUT MOSTLY KEEP THE SYSTEM
SLOWER LIKE THE OTHER MODELS. THE 12Z GFS OPERATIONAL MODEL NOW
APPEARS TO BE IN BETTER AGREEMENT WITH THE OTHERS.
GIVEN THE LATEST MODEL OUTPUT...THINK THAT THE ONSET OF ANY CHANCES
FOR PRECIPITATION WILL NOT OCCUR UNTIL SUNDAY AT THE EARLIEST AND
MORE LIKELY SUNDAY NIGHT IF THE SLOWER MODEL SOLUTION PANS OUT.
THERE IS SOME UNCERTAINTY THIS FAR OUT AS TO WHAT PRECIPITATION TYPE
WILL BE AS THE GFS SHOWS ABOVE FREEZING TEMPERATURES FOR MOST OF THE
EVENT. SOME DYNAMIC COOLING COULD RESULT IN A RAIN/SNOW MIX OVER TO
SNOW AND WILL SHOW THAT IN THE GRIDS ROUGHLY NORTHWEST OF A MEADE TO
LARNED LINE.
WITH NO SIGNIFICANT COLD AIR INTRUSIONS INDICATED BY THE
MODELS...TEMPERATURES SHOULD STAY FAIRLY SEASONAL FOR DECEMBER.
FOR WEEK TWO WILL MAINTAIN THE NEAR NORMAL TEMPERATURES AND
PRECIPITATION AS THE MODELS ARE INDICATING THE POSSIBILITY FOR
ANOTHER WAVE DROPPING INTO THE SOUTHWEST AND CLOSING OFF AROUND
DECEMBER 21ST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 47 45 53 / 60 60 60 30
GCK 35 46 44 50 / 40 60 60 20
EHA 37 47 42 51 / 50 60 60 10
LBL 39 49 47 53 / 50 60 60 20
HYS 34 45 43 51 / 40 60 60 50
P28 41 49 47 60 / 70 80 80 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
602 PM CST MON DEC 12 2011
.UPDATE...
.AVIATION /FOR THE 00Z TAF ISSUANCE/
VISIBILITIES AND CEILINGS WILL AGAIN BE A TREMENDOUS CHALLENGE TO
FORECAST THIS EVENING AND INTO TUESDAY. WARM AND MOIST ADVECTION IN
THE BOUNDARY LAYER ON THE NOSE OF SOUTHERLY WINDS WILL BE ON THE
INCREASE THROUGH THE PERIOD. A SIGNIFICANT DIFFERENCE EXISTS BETWEEN
NAM AND HRRR MODELS WITH RESPECT TO VISIBILITY OVERNIGHT. THE HRRR
IS A MUCH MORE AGGRESSIVE DEVELOPING DENSE FOG THAN IS THE NAM.
CURRENT THINKING IS THAT THE HRRR MAY BE MORE CORRECT SINCE
MOISTURE CONVERGENCE WOULD FAVOR MORE WIDESPREAD LOW VISIBILITIES
THAN THE VERY SHARP CUTOFF OF THE NAM, AND WE`LL HEDGE THE
FORECAST CLOSER TO THE RAPID REFRESH ESPECIALLY CONSIDERING THE
LOWERED VISBY`S OFFERED BY THE GFS LAMP PRODUCTS. CEILINGS WILL
REMAIN IN THE IFR CATEGORY OR LOWER THROUGH THE ENTIRE NIGHT. -RUSSELL
.PREV DISCUSSION... /ISSUED 319 PM CST MON DEC 12 2011/
DISCUSSION...
DAYS 1-2...
THE UPPER LEVEL LOW CURRENTLY ACROSS SOUTHERN CALIFORNIA WILL START
TO EJECT EAST NORTHEAST ACROSS THE FOUR CORNERS REGION TOMORROW AND
ACROSS THE CENTRAL PLAINS BY THURSDAY MORNING. A STRONG UPPER LEVEL
JET WILL ACCOMPANY THIS SYSTEM ENHANCING LIFT ACROSS OUR CWA TONIGHT
INTO WEDNESDAY MORNING. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
BE FOUND ACROSS THE EASTERN THIRD OF THE UNITED STATES. AT THE
SURFACE...AN AREA OF HIGH PRESSURE WILL BE FOUND ACROSS THE GULF OF
MEXICO AND CONTINUE TO BRING LOWER TO MID LEVEL MOISTURE NORTH INTO
OUR AREA. A SURFACE COLD FRONT IS ANTICIPATED TO CONTINUE TO MOVE
SOUTH ACROSS KANSAS THIS AFTERNOON AND STALL OUT ACROSS OUR CWA THIS
EVENING. THIS FRONTAL BOUNDARY WILL THEN MOVE NORTHWARD OVERNIGHT
AND BE POSITIONED ACROSS THE KS/NE BORDER BY TOMORROW MORNING. RAIN
CHANCES INCREASE OVERNIGHT AND LIGHT RAIN IS POSSIBLE ACROSS
SOUTHEAST PORTIONS OF THE CWA BY MIDNIGHT SPREADING ACROSS THE
REMAINDER OF THE CWA BY TOMORROW MORNING. PATCHY FOG IS ALSO
POSSIBLE OVERNIGHT BUT SHOULD DISSIPATE BY MORNING. LAST, THERE
COULD BE A FEW AREAS THAT EXPERIENCE LIGHT FREEZING RAIN ACROSS
HAMILTON, KEARNY, SCOTT, AND TREGO COUNTIES AFTER MIDNIGHT BUT NO
ACCUMULATION OF ICE IS EXPECTED AS SURFACE TEMPERATURES WILL BE
ABOVE FREEZING.
MOISTURE CONTINUES TO ADVECT NORTHWARD ACROSS THE AREA TOMORROW
AHEAD OF THE UPPER LEVEL TROUGH ALLOWING CLOUDY SKIES AND RAIN
CHANCES TO CONTINUE THROUGHOUT THE DAY. RAIN CHANCES RANGE FROM 50
PERCENT IN THE WEST TO OVER 70 PERCENT IN THE EAST. AN AREA OF LOW
PRESSURE IS EXPECTED TO MOVE FROM NORTHEASTERN NEW MEXICO TOMORROW
AFTERNOON AND SHIFT EAST INTO SOUTHEAST NEBRASKA BY WEDNESDAY
AFTERNOON. THIS WILL PUSH A COLD FRONT THROUGH THE AREA TOMORROW
NIGHT INTO WEDNESDAY MORNING. I HAVE KEPT IN THE WORDING OF ISOLATED
THUNDER ACROSS EASTERN PORTIONS OF THE CWA TOMORROW NIGHT ENDING IN
THE LATE MORNING AS THE COLD FRONT MOVES INTO WICHITA`S WFO. POPS
DECREASE FROM WEST TO EAST TOMORROW NIGHT INTO WEDNESDAY AND BELOW
15 PERCENT ACROSS THE ENTIRE CWA BY WEDNESDAY AFTERNOON. CLOUDS WILL
ALSO BE ON THE DECREASE AS THE SYSTEM EXITS OFF TO THE EAST LEAVING
PARTLY CLOUDY SKIES BY WEDNESDAY EVENING.
LOWS TONIGHT WILL RANGE FROM THE LOWER 30S IN THE NORTHWEST TO LOWER
40S IN THE SOUTHEAST WITH HIGHS TOMORROW WILL RISING INTO THE MID TO
UPPER 40S. OVERNIGHT LOWS TOMORROW NIGHT COULD ACTUALLY CLIMB ABOVE
TUESDAYS HIGHS DEPENDING ON DEWPOINTS. I WILL CONTINUE NEARLY STEADY
TEMPERATURES IN THE 40S OVERNIGHT WITH TH EXCEPTION OF NORTHEAST
PORTIONS OF THE CWA WHERE LOWS COULD DROP INTO THE UPPER 30S. HIGHS
ON WEDNESDAY ARE ANTICIPATED TO RANGE FROM THE LOWER 50S IN THE
NORTHWEST TO NEAR 60 IN THE SOUTHEAST.
DAYS 3-7...
THE MEDIUM RANGE MODELS SHOW A SECONDARY SHORTWAVE TROUGH LIFTING
OUT OF THE DESERT SOUTHWEST AND NORTHERN MEXICO ACROSS THE SOUTHERN
PLAINS LATER THIS WEEK. THE ENERGY WITH THIS WAVE IS PRETTY FAR
SOUTH AND WITH ALL THE BEST LOW LEVEL MOISTURE BEING SHUNTED SOUTH
BY THE MIDWEEK SYSTEM...THE DRY FORECAST LOOKS GOOD. THE MODELS SHOW
ANOTHER ANTICYCLONIC WAVE BREAK OCCURRING LATE THURSDAY AND THURSDAY
NIGHT. A SHORTWAVE TROUGH NOW SOUTHWEST OF THE ALEUTIAN ISLANDS IS
FORECAST TO TOP THE EASTERN PACIFIC RIDGE AND DIG SOUTH ACROSS THE
WESTERN STATES. THE ECMWF AND CANADIAN MODELS HAVE BEEN FAIRLY
CONSISTENT WITH THE TRACK AND TIMING OF THIS SYSTEM AS IT CLOSES OFF
AND HANGS BACK IN THE SOUTHWEST BEFORE LIFTING OUT TOWARD THE
CENTRAL/SOUTHERN PLAINS LATE NEXT WEEKEND. THE GFS HAS TENDED TO BE
MORE PROGRESSIVE AS IT TENDS TO DO. YESTERDAYS GFS ENSEMBLE MEMBERS
WERE MOSTLY SLOWER THAN THE OPERATIONAL RUN. TODAYS GFS ENSEMBLE
MEMBERS WERE STILL A LITTLE SCATTERED BUT MOSTLY KEEP THE SYSTEM
SLOWER LIKE THE OTHER MODELS. THE 12Z GFS OPERATIONAL MODEL NOW
APPEARS TO BE IN BETTER AGREEMENT WITH THE OTHERS.
GIVEN THE LATEST MODEL OUTPUT...THINK THAT THE ONSET OF ANY CHANCES
FOR PRECIPITATION WILL NOT OCCUR UNTIL SUNDAY AT THE EARLIEST AND
MORE LIKELY SUNDAY NIGHT IF THE SLOWER MODEL SOLUTION PANS OUT.
THERE IS SOME UNCERTAINTY THIS FAR OUT AS TO WHAT PRECIPITATION TYPE
WILL BE AS THE GFS SHOWS ABOVE FREEZING TEMPERATURES FOR MOST OF THE
EVENT. SOME DYNAMIC COOLING COULD RESULT IN A RAIN/SNOW MIX OVER TO
SNOW AND WILL SHOW THAT IN THE GRIDS ROUGHLY NORTHWEST OF A MEADE TO
LARNED LINE.
WITH NO SIGNIFICANT COLD AIR INTRUSIONS INDICATED BY THE
MODELS...TEMPERATURES SHOULD STAY FAIRLY SEASONAL FOR DECEMBER.
FOR WEEK TWO WILL MAINTAIN THE NEAR NORMAL TEMPERATURES AND
PRECIPITATION AS THE MODELS ARE INDICATING THE POSSIBILITY FOR
ANOTHER WAVE DROPPING INTO THE SOUTHWEST AND CLOSING OFF AROUND
DECEMBER 21ST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 47 45 53 / 50 60 60 30
GCK 35 46 44 50 / 50 60 60 20
EHA 37 47 42 51 / 50 60 60 10
LBL 39 49 47 53 / 50 60 60 20
HYS 34 45 43 51 / 50 60 60 50
P28 41 49 47 60 / 70 80 80 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN99/99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
328 PM CST SUN DEC 11 2011
.DISCUSSION...
LATEST WATER VAPOR LOOP AT 20Z WAS SHOWING THE UPPER TROUGH MOVING
SLOWLY ACROSS THE HIGH PLAINS FROM NEBRASKA INTO THE TEXAS
PANHANDLE. SHOWERS HAVE DEVELOPED OUT AHEAD OF THE WAVE IN OKLAHOMA
TODAY AND HAVE BEEN MOVING NORTHEAST SLOWLY THROUGH THE DAY.
SOUNDING FROM 12Z AT TOP AND SGF SHOWED PLENTY OF DRY AIR OFF THE
DECK THIS MORNING. SOME DRY AIR CONTINUES TO BE ENTRAINED THIS
EVENING IN THE EASTERN CWA PER MODEL TIME SECTIONS. LATEST RUN OF
THE RUC DOES NOT BRING ANY MEASURABLE PRECIPITATION AS FAR NORTH
INTO THE SOUTHERN CWA TONIGHT. THE UPPER WAVE WILL MOVE SLOWLY MOVE
ACROSS THE CENTRAL PLAINS TONIGHT WITH THE UPPER TROUGH AXIS MOVING
THROUGH THE EASTERN CWA BY 09Z MONDAY. 925-850 MB WINDS BECOME SOUTH
EARLY THIS EVENING THEN SOUTHWEST OVERNIGHT AND BY MORNING WILL
FOCUS MOISTURE TO THE EAST. EXPECT CLOUDS TO REMAIN THROUGH THE
NIGHT WITH SOME PATCHY FOG AND DRIZZLE POSSIBLE IN THE NORTHWEST
WHILE SPRINKLES ARE MORE LIKELY IN THE EAST. LOWS TONIGHT WILL
REMAIN ABOVE FREEZING SO NO FREEZING OR FROZEN PRECIPITATION IS
EXPECTED.
MONDAY SOME EARLY MORNING PATCHY DRIZZLE OR FOG IS POSSIBLE OFF THE
SNOW PACK TO THE WEST IN NORTH CENTRAL KANSAS. BY MID MORNING A
FRONTAL BOUNDARY WILL APPROACH FROM THE WEST BUT MAKES SLOW PROGRESS
THROUGH THE DAY AND BECOMES STATIONARY FROM SOUTHEAST NEBRASKA INTO
SOUTHWEST KANSAS. SOUTHERLY FLOW AHEAD OF THE FRONT WILL BRING
TEMPERATURES AGAIN IN THE MID AND UPPER 40S TO THE AREA.
53
MODELS ARE SIMILAR IN TAKING UPPER TROUGH OFF THE SOUTHERN CA COAST
MONDAY EVENING AND EJECTING IT NORTHEASTWARD INTO THE CENTRAL HIGH
PLAINS BY MIDDAY WEDNESDAY...THEN RAPIDLY INTO THE WESTERN GREAT
LAKES BY LATE WEDNESDAY NIGHT. THE MODELS ARE IN LESS AGREEMENT ON
HOW FAR SOUTHEAST THE COLD FRONT WILL PUSH SOUTHEAST INTO THE
NORTHWEST COUNTY WARNING AREA (CWA) MONDAY NIGHT BEFORE
STALLING...WITH THE NAM/SREF THE MOST AGGRESSIVE INTO THE NORTHWEST
1/3 OF THE CWA AND THE GFS/EC NOT BRINGING IT INTO THE NORTHWEST
CORNER AT ALL. WILL COMPROMISE FOR NOW WITH SOME
FREEZING/SUBFREEZING TEMPS IN THE FAR NORTHWEST CORNER BEHIND THE
FRONT AND WARMER ABOVE FREEZING TEMPS ELSEWHERE. WITH A CHANCE FOR
DRIZZLE/LIGHT RAIN INCREASING LATER IN THE NIGHT AND NO NON DIURNAL
TREND EXPECTED...CANNOT RULE OUT A WINDOW FOR SOME LIGHT FREEZING
PRECIP IN THE FAR NORTHWEST CORNER OF THE CWA 06-12Z
TUES...OTHERWISE EXPECT THE PRECIP WITH THIS SYSTEM TO BE A RAIN
EVENT TUESDAY THROUGH WEDNESDAY BEFORE ENDING WEDNESDAY NIGHT.
ELEVATED INSTABILITY AND FORCING LOOK SUFFICIENT FOR SOME THUNDER
POTENTIAL AHEAD OF THE FRONT IN THE DEEPER MOISTURE AXIS ACROSS THE
SOUTHEAST HALF OF THE CWA WHERE THE WARMER MORNING LOWS WEDNESDAY
WILL BE IN THE LOW TO MID 40S. AFTER HIGHS IN THE LOW TO MID 40S ON
TUESDAY...SHOULD SEE HIGHS RISE INTO THE LOW TO MIDDLE 50S FOR
WEDNESDAY.
AFTER THIS SYSTEM EXITS...MODELS DIVERGE THROUGH THE END OF THE WEEK
AND INTO NEXT WEEKEND ON HOW QUICKLY THE NEXT SHORTWAVE TO DIG INTO
THE SOUTHWEST CONUS WILL EJECT OUT INTO THE PLAINS. THE ECMWF MODEL
IS ABOUT 2 DAYS SLOWER WITH ITS ARRIVAL AND ASSOCIATED PRECIP THAN
THE GFS. WITH SUCH LOW CONFIDENCE ON ITS ARRIVAL TIME AND CURRENT
DRY FCST THROUGH SATURDAY...OPTED TO KEEP FCST DRY UNTIL SATURDAY
NIGHT/SUNDAY WITH LOW CHANCES FOR RAIN/FREEZING RAIN OR A SNOW
POTENTIAL. AFTER LOWS IN THE 20S AND HIGHS IN THE 30S BOTH FRIDAY
AND SATURDAY...HIGHS TEMPS SHOULD SLOWLY MODERATE AHEAD OF THE NEXT
UPPER TROUGH INTO THE 40S FOR HIGHS ON SUNDAY. 63
&&
.AVIATION...
THE VFR STRATUS DECK WILL CONTINUE TO TRACK NORTHEAST THROUGH THE
TAF FORECAST PERIOD. THE WINDS MAY TRY TO DISSIPATE THE CLOUD
DECK TEMPORARILY HOWEVER ENOUGH MOISTURE IS IN PLACE TO MAINTAIN
BKN TO OVC CIGS. TIGHT SFC PRESSURE GRADIENT WILL KEEP GUSTY
SOUTHERLY WINDS OVER 20 KTS THROUGH THE AFTERNOON HOURS...SUBSIDING
TO AROUND 10 KTS SUSTAINED OVERNIGHT. SHORT TERM MODEL ANALYSIS
SHOW THE STRATUS CIGS RETURNING TO MVFR OVER KMHK SUNDAY EVENING.
CONFIDENCE IS DECENT OVER KMHK WHERE HIGHEST CONCENTRATION OF LOW
LVL MOISTURE IS IN PLACE...HOWEVER IF TRENDS CHANGE KTOP AND KFOE
CIGS MAY BE LOWERED TO MVFR AS WELL DURING THE OVERNIGHT PERIOD.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1139 AM MST SUN DEC 11 2011
.UPDATE...
1059 AM MST SUN DEC 11 2011
18Z WATER VAPOR IMAGERY INDICATING LARGE POCKET OF DRY AIR IN
PLACE ACROSS THE PLAINS...WITH RUC H5 /PV ANALYSIS SUGGESTING WEAK
SHORT WAVE TROUGH DRIFTING OVER THE AREA...BUT HAVING VERY LITTLE
IMPACT ON SENSIBLE WX. AT THE SURFACE...TROUGH AXIS WAS DEVELOPING
ACROSS EASTERN COLORADO...WITH AREA OF STRATUS MOVING INTO THE CWA
IN AREA OF MOISTURE ADVECTION.
FOR THE REST OF THE AFTERNOON...THINK BREEZY SOUTHERLY WINDS WILL
CONTINUE TO SPREAD NORTH INTO EASTERN CWA AS MODELS APPEAR TO BE
OVERESTIMATING SNOW COVERS IMPACT ON MIXING. WHILE STRATUS SHOULD
LIMIT HIGHS SOME WHAT...TEMPS HAVE CLIMBED INTO THE UPPER 30S AS
CLOUDS ARRIVE SO WOULD NOT BE SURPRISED TO SEE A FEW SPOTS TOP OUT
IN THE 40S ACROSS EASTERN CWA. SHOULD SEE A VERY WIDE RANGE IN
TEMPS THIS AFTERNOON WITH AROUND 50 IN THE WEST...NEAR 40 IN THE
EAST...AND TEMPS STAYING IN THE 30S IN THE MCK AREA.
TONIGHT...MAIN CONCERNS WILL ONCE AGAIN BE FOG FORMATION AND
MINIMUM TEMPERATURES. MAIN ISSUE WITH RESPECT FOG FORMATION WILL
BE WHETHER OR NOT STRATUS CLEARS OUT...AS MOISTURE PROFILE EXPECTED
TO DEEPEN THROUGH THE EARLY EVENING...PROVIDING A FAVORABLE SET UP
FOR FOG SHOULD STATUS BREAK UP. LATEST GUIDANCE SUGGEST THAT
STRATUS DECK MAY SHIFT TO THE EAST PRIOR TO WEAK FRONTAL ZONE
MOVING ACROSS AREA...WHICH SHOULD PROVIDE AN OPPORTUNITY FOR FOG
TO DEVELOP. GIVEN THE MOISTURE PROFILE AND INCREASING WAA AROUND
09Z...COULD BRIEFLY SEE A PERIOD OF -FZDZ OVERNIGHT BUT THIS IS
EXPECTED TO BE VERY ISOLATED AT THE MOMENT. OTHERWISE...WILL
LIKELY SEE A SHARP GRADIENT IN TEMPERATURES OVERNIGHT...WITH
CLOUDS HOLDING TEMPS INTO THE UPPER 20S IN THE EXTREME EAST AND
TEMPS FALLING INTO THE TEENS ACROSS THE REST OF THE AREA.
JRM
&&
.DISCUSSION...
200 AM MST SUN DEC 11 2011
TODAY-MONDAY NIGHT...FORECAST ISSUES TODAY THROUGH MONDAY WILL BE
EXPECTED STRATUS DECK AHEAD OF A SFC TROUGH TODAY AND COLD FRONT
TONIGHT-MONDAY. THIS STRATUS DECK WILL BE GENERALLY EAST OF A LINE
FROM MCCOOK TO COLBY TO LEOTI AND WILL PROVIDE SOME FREEZING FOG
DURING THE NIGHT AND SOME CLOUDS DURING THE DAY WHICH MAY IMPACT
TEMPERATURE FORECAST. FOR TODAY TEMPERATURES SHOULD BE VERY CLOSE
TO SATURDAYS WITH 30S IN THE REMAINING DEEPER SNOW COVER WITH 40S
AND A FEW 50S ELSEWHERE...WARMEST ACROSS FAR EASTERN COLORADO. FOR
MONDAY SLIGHTLY COOLER READINGS IN THE 30S WITH LOW 40S IN FAR
EASTERN COLORADO.
FOR MONDAY NIGHT THROUGH TUESDAY NIGHT FOCUS IS ON INCREASING
MOISTURE MOVING INTO THE AREA AHEAD OF AN APPROACHING UPPER LOW
AND ASSOCIATED TROUGH WHICH BY LATE TUESDAY NIGHT SHOULD BE
REACHING COLORADO AND NEW MEXICO. MODELS REMAIN IN DISAGREEMENT
WITH THE HANDLING OF THIS SYSTEM WITH REGARDS TO HOW MUCH COLD AIR
LINGERS OVER THE AREA...MOISTURE AVAILABILITY AND TIMING JUST TO
NAME A FEW. IT STILL LOOKS LIKE WE MAY SEE SOME LIGHT FREEZING
DRIZZLE AND/OR LIGHT FREEZING RAIN LATE MONDAY NIGHT THROUGH
TUESDAY NIGHT WITH SOME OF THIS CHANGING TO LIGHT RAIN FROM
SOUTHWEST TO NORTHEAST. FOR NOW WILL MAKE VERY FEW CHANGES GIVEN
THE DISAGREEMENTS MENTIONED ABOVE.
007
WEDNESDAY-SATURDAY...UPPER LOW SWINGS ACROSS CWA WEDNESDAY WITH
MODELS DIFFERING QUITE A BIT ON STRENGTH RESULTING IN DIFFERENCES ON
HANDLING OF AMOUNTS AND WHERE PRECIP AXIS SETS UP AS IT SHIFTS EAST.
FOR NOW HAVE KEPT CHANCE POPS EAST DURING DAY WED AND LINGERED
SLIGHT CHANCE POPS WED NIGHT. BASED ON LATEST 00Z GUIDANCE SPEEDING
UP THIS FEATURE...NOT A LOT OF CONFIDENCE THERE WILL BE MUCH
LINGERING AFTER 00Z. TEMPERATURE PROFILES SHOULD SUPPORT ALL SNOW
WED MORNING TRANSITIONING TO SOME TYPE OF MIX OR ALL TO RAIN WED
AFTERNOON. POINT SOUNDINGS REFLECT MODEL DIFFERENCES IN TREATMENT OF
MID LEVEL MOISTURE...SO NOT A LOT OF CONFIDENCE DURING THE AFTERNOON
PERIOD ON TYPE.
SPLIT FLOW PATTERN DEVELOPS OVER CWA...WITH VERY LITTLE CONFIDENCE
THROUGH REMAINING EXTENDED PERIODS DUE TO LARGE SPREAD RUN TO RUN ON
HANDLING OF SMALLER SCALE FEATURES. FOR NOW HAVE KEPT SLIGHT CHANCE
POPS FOR FRIDAY/FRIDAY NIGHT TO ACCOUNT FOR QUICK MOVING SHORTWAVE
TROUGH AND ASSOCIATED COLD FRONT. QUITE A BIT A SPREAD ON HANDLING
OF THIS FEATURE...SO NOT PARTICULARLY CONFIDENT.
&&
.AVIATION...
1139 AM MST SUN DEC 11 2011
THE STRATUS LAYER HAS NOT RISEN MUCH THIS MORNING...AND IT
CONTINUES TO MOVE NORTHWARD. GIVEN ITS MOVEMENT...IT SHOULD STAY
EAST OF KGLD...MUCH IS EXPECTED TO BRING MVFR CEILINGS TO KMCK BY
20Z. FOG IS AGAIN EXPECTED OVERNIGHT AT KMCK...AND THE LOW LEVEL
MIXING AT KGLD SHOULD KEEP KGLD VFR. WINDS WILL BE SOUTHERLY THIS
AFTERNOON...CHANGING TO WESTERLY TONIGHT AND NORTHERLY BY TOMORROW
MORNING. THE TRANSITION TO FOG AT KMCK SHOULD BE SIMILAR TO LAST
NIGHT...WITH NEARLY CALM WINDS INHIBITING MIXING OF AIR NEAR THE
SURFACE...THOUGH THE RATE AT WHICH THE STRATUS DECK MOVES EASTWARD
COULD IMPACT THE FOG FORMATION. VISIBILITIES WILL BEGIN TO
DECREASE IN THE EVENING AT KMCK...AND THE LOWEST VISIBILITIES WILL
BE IN THE EARLY MORNING. HAVE KEPT THE PREVAILING CONDITIONS IN
THE EARLY MORNING LIFR...BUT THERE IS THE POTENTIAL FOR PERIODS OF
VLIFR CONDITIONS. VISIBILITIES WILL IMPROVE IN THE LATE MORNING AS
DAYTIME MIXING INCREASES.
CJS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1115 AM MST SUN DEC 11 2011
.UPDATE...
1059 AM MST SUN DEC 11 2011
18Z WATER VAPOR IMAGERY INDICATING LARGE POCKET OF DRY AIR IN
PLACE ACROSS THE PLAINS...WITH RUC H5 /PV ANALYSIS SUGGESTING WEAK
SHORT WAVE TROUGH DRIFTING OVER THE AREA...BUT HAVING VERY LITTLE
IMPACT ON SENSIBLE WX. AT THE SURFACE...TROUGH AXIS WAS DEVELOPING
ACROSS EASTERN COLORADO...WITH AREA OF STRATUS MOVING INTO THE CWA
IN AREA OF MOISTURE ADVECTION.
FOR THE REST OF THE AFTERNOON...THINK BREEZY SOUTHERLY WINDS WILL
CONTINUE TO SPREAD NORTH INTO EASTERN CWA AS MODELS APPEAR TO BE
OVERESTIMATING SNOW COVERS IMPACT ON MIXING. WHILE STRATUS SHOULD
LIMIT HIGHS SOME WHAT...TEMPS HAVE CLIMBED INTO THE UPPER 30S AS
CLOUDS ARRIVE SO WOULD NOT BE SURPRISED TO SEE A FEW SPOTS TOP OUT
IN THE 40S ACROSS EASTERN CWA. SHOULD SEE A VERY WIDE RANGE IN
TEMPS THIS AFTERNOON WITH AROUND 50 IN THE WEST...NEAR 40 IN THE
EAST...AND TEMPS STAYING IN THE 30S IN THE MCK AREA.
TONIGHT...MAIN CONCERNS WILL ONCE AGAIN BE FOG FORMATION AND
MINIMUM TEMPERATURES. MAIN ISSUE WITH RESPECT FOG FORMATION WILL
BE WHETHER OR NOT STRATUS CLEARS OUT...AS MOISTURE PROFILE EXPECTED
TO DEEPEN THROUGH THE EARLY EVENING...PROVIDING A FAVORABLE SET UP
FOR FOG SHOULD STATUS BREAK UP. LATEST GUIDANCE SUGGEST THAT
STRATUS DECK MAY SHIFT TO THE EAST PRIOR TO WEAK FRONTAL ZONE
MOVING ACROSS AREA...WHICH SHOULD PROVIDE AN OPPORTUNITY FOR FOG
TO DEVELOP. GIVEN THE MOISTURE PROFILE AND INCREASING WAA AROUND
09Z...COULD BRIEFLY SEE A PERIOD OF -FZDZ OVERNIGHT BUT THIS IS
EXPECTED TO BE VERY ISOLATED AT THE MOMENT. OTHERWISE...WILL
LIKELY SEE A SHARP GRADIENT IN TEMPERATURES OVERNIGHT...WITH
CLOUDS HOLDING TEMPS INTO THE UPPER 20S IN THE EXTREME EAST AND
TEMPS FALLING INTO THE TEENS ACROSS THE REST OF THE AREA.
JRM
&&
.DISCUSSION...
200 AM MST SUN DEC 11 2011
TODAY-MONDAY NIGHT...FORECAST ISSUES TODAY THROUGH MONDAY WILL BE
EXPECTED STRATUS DECK AHEAD OF A SFC TROUGH TODAY AND COLD FRONT
TONIGHT-MONDAY. THIS STRATUS DECK WILL BE GENERALLY EAST OF A LINE
FROM MCCOOK TO COLBY TO LEOTI AND WILL PROVIDE SOME FREEZING FOG
DURING THE NIGHT AND SOME CLOUDS DURING THE DAY WHICH MAY IMPACT
TEMPERATURE FORECAST. FOR TODAY TEMPERATURES SHOULD BE VERY CLOSE
TO SATURDAYS WITH 30S IN THE REMAINING DEEPER SNOW COVER WITH 40S
AND A FEW 50S ELSEWHERE...WARMEST ACROSS FAR EASTERN COLORADO. FOR
MONDAY SLIGHTLY COOLER READINGS IN THE 30S WITH LOW 40S IN FAR
EASTERN COLORADO.
FOR MONDAY NIGHT THROUGH TUESDAY NIGHT FOCUS IS ON INCREASING
MOISTURE MOVING INTO THE AREA AHEAD OF AN APPROACHING UPPER LOW
AND ASSOCIATED TROUGH WHICH BY LATE TUESDAY NIGHT SHOULD BE
REACHING COLORADO AND NEW MEXICO. MODELS REMAIN IN DISAGREEMENT
WITH THE HANDLING OF THIS SYSTEM WITH REGARDS TO HOW MUCH COLD AIR
LINGERS OVER THE AREA...MOISTURE AVAILABILITY AND TIMING JUST TO
NAME A FEW. IT STILL LOOKS LIKE WE MAY SEE SOME LIGHT FREEZING
DRIZZLE AND/OR LIGHT FREEZING RAIN LATE MONDAY NIGHT THROUGH
TUESDAY NIGHT WITH SOME OF THIS CHANGING TO LIGHT RAIN FROM
SOUTHWEST TO NORTHEAST. FOR NOW WILL MAKE VERY FEW CHANGES GIVEN
THE DISAGREEMENTS MENTIONED ABOVE.
007
WEDNESDAY-SATURDAY...UPPER LOW SWINGS ACROSS CWA WEDNESDAY WITH
MODELS DIFFERING QUITE A BIT ON STRENGTH RESULTING IN DIFFERENCES ON
HANDLING OF AMOUNTS AND WHERE PRECIP AXIS SETS UP AS IT SHIFTS EAST.
FOR NOW HAVE KEPT CHANCE POPS EAST DURING DAY WED AND LINGERED
SLIGHT CHANCE POPS WED NIGHT. BASED ON LATEST 00Z GUIDANCE SPEEDING
UP THIS FEATURE...NOT A LOT OF CONFIDENCE THERE WILL BE MUCH
LINGERING AFTER 00Z. TEMPERATURE PROFILES SHOULD SUPPORT ALL SNOW
WED MORNING TRANSITIONING TO SOME TYPE OF MIX OR ALL TO RAIN WED
AFTERNOON. POINT SOUNDINGS REFLECT MODEL DIFFERENCES IN TREATMENT OF
MID LEVEL MOISTURE...SO NOT A LOT OF CONFIDENCE DURING THE AFTERNOON
PERIOD ON TYPE.
SPLIT FLOW PATTERN DEVELOPS OVER CWA...WITH VERY LITTLE CONFIDENCE
THROUGH REMAINING EXTENDED PERIODS DUE TO LARGE SPREAD RUN TO RUN ON
HANDLING OF SMALLER SCALE FEATURES. FOR NOW HAVE KEPT SLIGHT CHANCE
POPS FOR FRIDAY/FRIDAY NIGHT TO ACCOUNT FOR QUICK MOVING SHORTWAVE
TROUGH AND ASSOCIATED COLD FRONT. QUITE A BIT A SPREAD ON HANDLING
OF THIS FEATURE...SO NOT PARTICULARLY CONFIDENT.
&&
.AVIATION...
1022 AM MST SUN DEC 11 2011
FOR THE 18Z TAFS...AS MIXING CONTINUES TO INCREASE VISIBILITIES
AND CEILINGS ACROSS THE REGION...AFTERNOON CONDITIONS WILL BE VFR
AT THE TERMINALS. FOG IS AGAIN EXPECTED OVERNIGHT AT KMCK...AND
THE LOW LEVEL MIXING AT KGLD SHOULD KEEP KGLD VFR. WINDS WILL BE
SOUTHERLY THIS AFTERNOON...CHANGING TO WESTERLY TONIGHT AND
NORTHERLY BY TOMORROW MORNING. THE TRANSITION TO FOG AT KMCK
SHOULD BE SIMILAR TO LAST NIGHT...WITH NEARLY CALM WINDS
INHIBITING MIXING OF AIR NEAR THE SURFACE. VISIBILITIES WILL BEGIN
TO DECREASE IN THE EVENING AT KMCK...AND THE LOWEST VISIBILITIES
WILL BE IN THE EARLY MORNING. HAVE KEPT THE PREVAILING CONDITIONS
IN THE EARLY MORNING LIFR...BUT THERE IS THE POTENTIAL FOR
PERIODS OF VLIFR CONDITIONS. VISIBILITIES WILL IMPROVE IN THE LATE
MORNING AS DAYTIME MIXING INCREASES.
CJS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1203 PM CST SUN DEC 11 2011
.UPDATE...
LOW LEVEL WARM/MOIST ADVECTION HAS RESULTED IN RISING TEMPERATURES
EVEN WITH LIMITED INSOLATION AND THE FORECAST WAS ADJUSTED TO BUMP
HIGH TEMPERATURES UP SLIGHTLY. IN ADDITION...A FEW LIGHT RAIN
SHOWERS/SPRINKLES HAVE DEVELOPED ACROSS SOUTH CENTRAL KANSAS
WITHIN A SHALLOW ISENTROPIC UPGLIDE REGIME AND WILL INCLUDE A
MENTION IN THE FORECAST UPDATE.
MCGUIRE
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
PATCHY MVFR CIGS REMAIN ACROSS PORTIONS OF CENTRAL KANSAS BUT VFR
IS EXPECTED TO PREVAIL ACROSS THE AREA BY MID AFTERNOON WITH
CEILINGS AROUND 5000 FEET ANTICIPATED. GUSTY SOUTHERLY WINDS AT 20
TO 30 KNOTS WILL ALSO DEVELOP AS LOW PRESSURE AT THE SURFACE CONTINUES
TO DEEPEN ACROSS THE CENTRAL HIGH PLAINS HELPING TO TIGHTEN THE
GRADIENT ACROSS CENTRAL KANSAS. A FEW LIGHT SHOWERS/SPRINKLES MAY
IMPACT KICT-KHUT AND KSLN THROUGH THE AFTERNOON HOURS GRADUALLY
SHIFTING EASTWARD THROUGH THE EVENING. SOME CONCERN THAT
CEILINGS/VISIBILITIES WILL FALL TO MVFR/IFR ONCE AGAIN THIS EVENING
AND OVERNIGHT AND HINTED AT THIS IN THE LATEST TAFS.
MCGUIRE
&&
.PREV DISCUSSION... /ISSUED 729 AM CST SUN DEC 11 2011/
UPDATE...
VISIBILITIES HAVE GREATLY IMPROVED IN SOUTHEAST KANSAS...THUS HAVE
CANCELLED THE DENSE FOG ADVISORY. EXPECT VISIBILITIES TO
IMPROVE...BUT A DECK OF STRATUS SHOULD REMAIN OVER THE AREA FOR
MUCH OF THE DAY.
VP
PREV DISCUSSION... /ISSUED 607 AM CST SUN DEC 11 2011/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
BOTH CIGS & VSBYS CONTINUE TO POSE PROBLEMS EARLY THIS MORNING WITH
CONSIDERABLE VARIATIONS IN BOTH REGARDS. BY FAR THE WORST SITUATION IS
OVER KCNU WHERE 1/4 FZFG VV001 HAS SHROUDED THE TERMINAL SINCE 0652Z.
BOTH CIGS & VSBYS IMPROVE GREATLY JUST S OF THE TERMINAL...EVEN AS
CLOSE AS KCFV WITH CLEAR SKIES AND 3-5SM VSBYS HAVE PREVAILED ALL NGT.
HOWEVER IR IMAGERY DEPICTS FG TRYING TO DEVELOP SW OF THE TERMINAL. AS
SUCH AM RELUCTANT TO PLACE TERMINAL IN MVFR STATUS TIL ~16Z. KCNU WILL
REQUIRE VERY CLOSE ATTENTION DURING THIS 4-HOUR PERIOD. ALTHOUGH STILL
IN MVFR STATUS THE REMAINING TERIMALS ARE IN MUCH BETTER SHAPE WITH
3-5SM VSBYS & 2000-2800FT CIGS IN MOST AREAS. WITH STRONG LWR-DECK
TROF REMAINING POSITIONED ALONG FRONT RANGE...A BROAD FETCH OF RICH
LWR-DECK MOISTURE CONTINUING TO STREAM N/NW ACROSS KS DICTATES KEEPING
THESE TERMINALS IN MVFR STATUS THROUGHOUT THE AFTERNOON WITH WINDS
INCREASING TO 17-22KTS/20-25MPH SUSTAINED WITH ~30KT/35MPH GUSTS
LIKELY THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 306 AM CST SUN DEC 11 2011/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE PRECIP CHANCES FOR THE TUE-WED TIME
FRAME.
SYNOPSIS:
THE CENTRAL AND SOUTHERN PLAINS ARE IN BETWEEN A SHORTWAVE THAT IS
DEPARTING OFF OF THE EAST COAST AND ANOTHER ONE THAT IS STARTING TO
DIG OFF OF THE WEST COAST. AT THE SURFACE THE RIDGE EXTENDS FROM THE
OHIO VALLEY INTO CENTRAL TX WITH LEE TROUGHING STRENGTHENING OVER
THE NORTHERN HIGH PLAINS. THIS HAS RESULTED IN SW SURFACE WINDS
INCREASING OVERNIGHT.
TODAY-TONIGHT:
DENSE FOG IS EXPECTED TO CONTINUE EARLY THIS MORNING OVER PORTIONS
OF THE FLINT HILLS INTO SE KS. CONFIDENCE IS HIGH THAT THE FOG WILL
NOT LINGER INTO THE LATE MORNING HOURS AND SHOULD LIFT BY 15Z.
JUST LIKE YESTERDAY THE CLOUD FORECAST WILL BE VERY CHALLENGING TODAY
AND WILL PLAY HAVOC WITH TEMPS. SATELLITE CURRENTLY SHOWS A LARGE
AREA OF STRATUS EXTENDING FROM THE TX PANHANDLE INTO SOUTH CENTRAL KS
AND SLOWLY WORKING TO THE NORTHEAST. WHILE WE MAY SEE A FEW BRIEF
BREAKS THIS MORNING...BY THE AFTERNOON HOURS FEEL THAT LOW CLOUDS
WILL ENCOMPASS THE MAJORITY OF THE FORECAST AREA. HOWEVER EVEN WITH
CLOUD COVER...GUSTY SOUTH WINDS WILL WARM ADVECT HIGHER TEMPS INTO
THE AREA WITH ALL LOCATIONS EXPECTED TO BE IN THE 40S TODAY. LOW
LEVEL MOISTURE WILL CONTINUE TO STREAM INTO CENTRAL AND SOUTH
CENTRAL KS TONIGHT WHICH WILL KEEP LOW CLOUDS IN PLACE. WILL GO
AHEAD AND LEAVE SOME DRIZZLE AND LIGHT FOG IN LATE TONIGHT FOR
CENTRAL KS...BUT BECAUSE OF LACK OF LOW LEVEL ISENTROPIC LIFT AND
DEEP SATURATION...NOT TOO IMPRESSED WITH WIDESPREAD HEAVY DRIZZLE
CHANCES.
MON-WED NIGHT:
BY MON AFTERNOON THE UPPER SHORTWAVE WILL BE DIGGING OFF OF THE
SOUTHERN CA COAST. THIS WILL ALLOW MOISTURE TO CONTINUE TO STREAM
INTO THE SOUTHERN AND CENTRAL PLAINS. BY MON NIGHT ISENTROPIC LIFT
AND MOISTURE TRANSPORT WILL INCREASE ENOUGH THAT SOME RAIN SHOWERS
SHOULD DEVELOP. SOMETHING TO KEEP AN EYE ON FOR LATER SHIFTS WILL BE
THE POSITION OF THE COLD FRONT FOR THE LATE MON NIGHT TIME FRAME.
THE NAM IS QUITE A BIT FURTHER SOUTH WITH THIS FRONT COMPARED TO THE
GFS AND ECMWF. IF THE NAM VERIFIES THERE MAY BE A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR FREEZING DRIZZLE OVER CENTRAL KS. HOWEVER
SINCE THE NAM IS CURRENTLY THE OUTLIER...WILL LEAVE TEMPS ON MON
NIGHT OVER CENTRAL KS JUST ABOVE FREEZING.
THE UPPER WAVE IS EXPECTED TO QUICKLY APPROACH THE SOUTHERN PLAINS
ON TUE NIGHT INTO WED. THIS IS WHEN WE CURRENTLY HAVE THE HIGHEST
CONFIDENCE IN MUCH OF THE AREA SEEING RAINFALL AS THE UPPER DYNAMICS
DIRECTLY IMPACT THE AREA. CURRENTLY EXPECTING PRECIP CHANCES TO END
VERY QUICKLY WED NIGHT WITH MOST OF THE FORECAST AREA DRY BY EARLY
THU MORNING. THE PROGRESSIVE NATURE OF THIS SYSTEM DOES NOT ALLOW
ANY OF THE HIGHER THETA-E AIR TO BE WRAPPED AROUND THE BACKSIDE OF
THE LOW WHERE IT COULD INTERACT WITH THE COLDER AIR. THEREFORE
STILL NOT EXPECTING ANY WIDESPREAD HAZARDOUS WINTER WEATHER THROUGH
THIS TIME PERIOD.
THU-SUN:
BY THU AFTERNOON THIS WAVE WILL BE AFFECTING THE EASTERN SEABOARD AS
ANOTHER UPPER IMPULSE DIVES OVER THE GREAT LAKES REGION. THIS WILL
RESULT IN SURFACE HIGH PRESSURE SETTLING OVER THE CENTRAL AND
SOUTHERN PLAINS THROUGH FRI. BOTH THE GFS AND ECMWF AGREE ON
DEVELOPING ANOTHER UPPER LOW OVER SOUTHERN CA BY FRI AFTERNOON AND
IS EXPECTED TO REMAIN OVER THE DESERT SOUTHWEST THROUGH THE WEEKEND.
LAWSON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VERY TOUGH FORECAST WITH 00Z MODELS CONTINUING TO STRUGGLE WITH
LOW LEVEL MOISTURE. LATEST RUC DOES NOT APPEAR TO BE AS GOOD AS
EARLIER RUNS...SO THE OVERNIGHT PART OF THE FORECAST PRIMARILY
BASED ON OBSERVATIONS/TRENDS AND BEST ESTIMATE OF HOW CONDITIONS
WILL EVOLVE. WORST CONDITIONS HAVE BEEN OCCURRING ON EDGES OF
STRATUS SO FAR THIS EVENING. ANTICIPATE THAT STRATUS/PATCHY DENSE
FOG WILL INCREASE OVER VIRTUALLY ENTIRE AREA OVER THE NEXT FEW
HOURS...AS WEAK SOUTH FLOW ADVECTING SLIGHTLY WARMER/MOISTER AIR
UPSLOPE INTO CHILLED AND SATURATED AIRMASS. NOD IS GIVEN TO THE
NAM WHICH STILL SUGGEST INFLUX OF 850MB-700MB MOISTURE MID TO LATE
MORNING...WHICH WILL LIKELY KEEP MANY AREAS OVERCAST THROUGHOUT
THE PERIOD. EXCEPTION MAY BE SOUTHEAST KS ONCE AGAIN...BUT DO
EXPECT MOISTURE TO ARRIVE THERE BY LATE AFTERNOON. IF THE 850MB-
700MB MOISTURE ARRIVES PRIOR TO BURNING THROUGH THE VERY LOW
CLOUDS...COULD BE STUCK IN IFR THROUGHOUT MOST/ALL DAY. APPEARS
THAT KRSL/KHUT/KSLN WILL SEE MORE MVFR OR IFR CONDITIONS DEVELOP
DURING THE EVENING. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 46 35 48 36 / 10 10 10 20
HUTCHINSON 46 35 47 35 / 10 10 10 20
NEWTON 46 34 48 36 / 10 10 10 20
ELDORADO 46 35 48 36 / 10 10 10 20
WINFIELD-KWLD 48 36 49 37 / 10 10 10 30
RUSSELL 46 33 44 33 / 10 10 10 20
GREAT BEND 45 34 45 34 / 10 10 10 20
SALINA 46 35 46 34 / 10 10 10 20
MCPHERSON 46 35 47 35 / 10 10 10 20
COFFEYVILLE 51 35 48 37 / 10 10 10 30
CHANUTE 50 34 48 36 / 10 10 10 30
IOLA 49 34 48 36 / 10 10 10 30
PARSONS-KPPF 50 34 48 37 / 10 10 10 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
729 AM CST SUN DEC 11 2011
.UPDATE...
VISIBILITIES HAVE GREATLY IMPROVED IN SOUTHEAST KANSAS...THUS HAVE
CANCELLED THE DENSE FOG ADVISORY. EXPECT VISIBILITIES TO
IMPROVE...BUT A DECK OF STRATUS SHOULD REMAIN OVER THE AREA FOR
MUCH OF THE DAY.
VP
&&
.PREV DISCUSSION... /ISSUED 607 AM CST SUN DEC 11 2011/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
BOTH CIGS & VSBYS CONTINUE TO POSE PROBLEMS EARLY THIS MORNING WITH
CONSIDERABLE VARIATIONS IN BOTH REGARDS. BY FAR THE WORST SITUATION IS
OVER KCNU WHERE 1/4 FZFG VV001 HAS SHROUDED THE TERMINAL SINCE 0652Z.
BOTH CIGS & VSBYS IMPROVE GREATLY JUST S OF THE TERMINAL...EVEN AS
CLOSE AS KCFV WITH CLEAR SKIES AND 3-5SM VSBYS HAVE PREVAILED ALL NGT.
HOWEVER IR IMAGERY DEPICTS FG TRYING TO DEVELOP SW OF THE TERMINAL. AS
SUCH AM RELUCTANT TO PLACE TERMINAL IN MVFR STATUS TIL ~16Z. KCNU WILL
REQUIRE VERY CLOSE ATTENTION DURING THIS 4-HOUR PERIOD. ALTHOUGH STILL
IN MVFR STATUS THE REMAINING TERIMALS ARE IN MUCH BETTER SHAPE WITH
3-5SM VSBYS & 2000-2800FT CIGS IN MOST AREAS. WITH STRONG LWR-DECK
TROF REMAINING POSITIONED ALONG FRONT RANGE...A BROAD FETCH OF RICH
LWR-DECK MOISTURE CONTINUING TO STREAM N/NW ACROSS KS DICTATES KEEPING
THESE TERMINALS IN MVFR STATUS THROUGHOUT THE AFTERNOON WITH WINDS
INCREASING TO 17-22KTS/20-25MPH SUSTAINED WITH ~30KT/35MPH GUSTS
LIKELY THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 306 AM CST SUN DEC 11 2011/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE PRECIP CHANCES FOR THE TUE-WED TIME
FRAME.
SYNOPSIS:
THE CENTRAL AND SOUTHERN PLAINS ARE IN BETWEEN A SHORTWAVE THAT IS
DEPARTING OFF OF THE EAST COAST AND ANOTHER ONE THAT IS STARTING TO
DIG OFF OF THE WEST COAST. AT THE SURFACE THE RIDGE EXTENDS FROM THE
OHIO VALLEY INTO CENTRAL TX WITH LEE TROUGHING STRENGTHENING OVER
THE NORTHERN HIGH PLAINS. THIS HAS RESULTED IN SW SURFACE WINDS
INCREASING OVERNIGHT.
TODAY-TONIGHT:
DENSE FOG IS EXPECTED TO CONTINUE EARLY THIS MORNING OVER PORTIONS
OF THE FLINT HILLS INTO SE KS. CONFIDENCE IS HIGH THAT THE FOG WILL
NOT LINGER INTO THE LATE MORNING HOURS AND SHOULD LIFT BY 15Z.
JUST LIKE YESTERDAY THE CLOUD FORECAST WILL BE VERY CHALLENGING TODAY
AND WILL PLAY HAVOC WITH TEMPS. SATELLITE CURRENTLY SHOWS A LARGE
AREA OF STRATUS EXTENDING FROM THE TX PANHANDLE INTO SOUTH CENTRAL KS
AND SLOWLY WORKING TO THE NORTHEAST. WHILE WE MAY SEE A FEW BRIEF
BREAKS THIS MORNING...BY THE AFTERNOON HOURS FEEL THAT LOW CLOUDS
WILL ENCOMPASS THE MAJORITY OF THE FORECAST AREA. HOWEVER EVEN WITH
CLOUD COVER...GUSTY SOUTH WINDS WILL WARM ADVECT HIGHER TEMPS INTO
THE AREA WITH ALL LOCATIONS EXPECTED TO BE IN THE 40S TODAY. LOW
LEVEL MOISTURE WILL CONTINUE TO STREAM INTO CENTRAL AND SOUTH
CENTRAL KS TONIGHT WHICH WILL KEEP LOW CLOUDS IN PLACE. WILL GO
AHEAD AND LEAVE SOME DRIZZLE AND LIGHT FOG IN LATE TONIGHT FOR
CENTRAL KS...BUT BECAUSE OF LACK OF LOW LEVEL ISENTROPIC LIFT AND
DEEP SATURATION...NOT TOO IMPRESSED WITH WIDESPREAD HEAVY DRIZZLE
CHANCES.
MON-WED NIGHT:
BY MON AFTERNOON THE UPPER SHORTWAVE WILL BE DIGGING OFF OF THE
SOUTHERN CA COAST. THIS WILL ALLOW MOISTURE TO CONTINUE TO STREAM
INTO THE SOUTHERN AND CENTRAL PLAINS. BY MON NIGHT ISENTROPIC LIFT
AND MOISTURE TRANSPORT WILL INCREASE ENOUGH THAT SOME RAIN SHOWERS
SHOULD DEVELOP. SOMETHING TO KEEP AN EYE ON FOR LATER SHIFTS WILL BE
THE POSITION OF THE COLD FRONT FOR THE LATE MON NIGHT TIME FRAME.
THE NAM IS QUITE A BIT FURTHER SOUTH WITH THIS FRONT COMPARED TO THE
GFS AND ECMWF. IF THE NAM VERIFIES THERE MAY BE A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR FREEZING DRIZZLE OVER CENTRAL KS. HOWEVER
SINCE THE NAM IS CURRENTLY THE OUTLIER...WILL LEAVE TEMPS ON MON
NIGHT OVER CENTRAL KS JUST ABOVE FREEZING.
THE UPPER WAVE IS EXPECTED TO QUICKLY APPROACH THE SOUTHERN PLAINS
ON TUE NIGHT INTO WED. THIS IS WHEN WE CURRENTLY HAVE THE HIGHEST
CONFIDENCE IN MUCH OF THE AREA SEEING RAINFALL AS THE UPPER DYNAMICS
DIRECTLY IMPACT THE AREA. CURRENTLY EXPECTING PRECIP CHANCES TO END
VERY QUICKLY WED NIGHT WITH MOST OF THE FORECAST AREA DRY BY EARLY
THU MORNING. THE PROGRESSIVE NATURE OF THIS SYSTEM DOES NOT ALLOW
ANY OF THE HIGHER THETA-E AIR TO BE WRAPPED AROUND THE BACKSIDE OF
THE LOW WHERE IT COULD INTERACT WITH THE COLDER AIR. THEREFORE
STILL NOT EXPECTING ANY WIDESPREAD HAZARDOUS WINTER WEATHER THROUGH
THIS TIME PERIOD.
THU-SUN:
BY THU AFTERNOON THIS WAVE WILL BE AFFECTING THE EASTERN SEABOARD AS
ANOTHER UPPER IMPULSE DIVES OVER THE GREAT LAKES REGION. THIS WILL
RESULT IN SURFACE HIGH PRESSURE SETTLING OVER THE CENTRAL AND
SOUTHERN PLAINS THROUGH FRI. BOTH THE GFS AND ECMWF AGREE ON
DEVELOPING ANOTHER UPPER LOW OVER SOUTHERN CA BY FRI AFTERNOON AND
IS EXPECTED TO REMAIN OVER THE DESERT SOUTHWEST THROUGH THE WEEKEND.
LAWSON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VERY TOUGH FORECAST WITH 00Z MODELS CONTINUING TO STRUGGLE WITH
LOW LEVEL MOISTURE. LATEST RUC DOES NOT APPEAR TO BE AS GOOD AS
EARLIER RUNS...SO THE OVERNIGHT PART OF THE FORECAST PRIMARILY
BASED ON OBSERVATIONS/TRENDS AND BEST ESTIMATE OF HOW CONDITIONS
WILL EVOLVE. WORST CONDITIONS HAVE BEEN OCCURRING ON EDGES OF
STRATUS SO FAR THIS EVENING. ANTICIPATE THAT STRATUS/PATCHY DENSE
FOG WILL INCREASE OVER VIRTUALLY ENTIRE AREA OVER THE NEXT FEW
HOURS...AS WEAK SOUTH FLOW ADVECTING SLIGHTLY WARMER/MOISTER AIR
UPSLOPE INTO CHILLED AND SATURATED AIRMASS. NOD IS GIVEN TO THE
NAM WHICH STILL SUGGEST INFLUX OF 850MB-700MB MOISTURE MID TO LATE
MORNING...WHICH WILL LIKELY KEEP MANY AREAS OVERCAST THROUGHOUT
THE PERIOD. EXCEPTION MAY BE SOUTHEAST KS ONCE AGAIN...BUT DO
EXPECT MOISTURE TO ARRIVE THERE BY LATE AFTERNOON. IF THE 850MB-
700MB MOISTURE ARRIVES PRIOR TO BURNING THROUGH THE VERY LOW
CLOUDS...COULD BE STUCK IN IFR THROUGHOUT MOST/ALL DAY. APPEARS
THAT KRSL/KHUT/KSLN WILL SEE MORE MVFR OR IFR CONDITIONS DEVELOP
DURING THE EVENING. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 46 35 48 36 / 10 10 10 20
HUTCHINSON 44 35 47 35 / 10 10 10 20
NEWTON 44 34 48 36 / 10 10 10 20
ELDORADO 45 35 48 36 / 10 10 10 20
WINFIELD-KWLD 47 36 49 37 / 10 10 10 30
RUSSELL 43 33 44 33 / 10 10 10 20
GREAT BEND 45 34 45 34 / 10 10 10 20
SALINA 46 35 46 34 / 10 10 10 20
MCPHERSON 44 35 47 35 / 10 10 10 20
COFFEYVILLE 48 35 48 37 / 10 10 10 30
CHANUTE 46 34 48 36 / 10 10 10 30
IOLA 45 34 48 36 / 10 10 10 30
PARSONS-KPPF 47 34 48 37 / 10 10 10 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
607 AM CST SUN DEC 11 2011
.AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
BOTH CIGS & VSBYS CONTINUE TO POSE PROBLEMS EARLY THIS MORNING WITH
CONSIDERABLE VARIATIONS IN BOTH REGARDS. BY FAR THE WORST SITUATION IS
OVER KCNU WHERE 1/4 FZFG VV001 HAS SHROUDED THE TERMINAL SINCE 0652Z.
BOTH CIGS & VSBYS IMPROVE GREATLY JUST S OF THE TERMINAL...EVEN AS
CLOSE AS KCFV WITH CLEAR SKIES AND 3-5SM VSBYS HAVE PREVAILED ALL NGT.
HOWEVER IR IMAGERY DEPICTS FG TRYING TO DEVELOP SW OF THE TERMINAL. AS
SUCH AM RELUCTANT TO PLACE TERMINAL IN MVFR STATUS TIL ~16Z. KCNU WILL
REQUIRE VERY CLOSE ATTENTION DURING THIS 4-HOUR PERIOD. ALTHOUGH STILL
IN MVFR STATUS THE REMAINING TERIMALS ARE IN MUCH BETTER SHAPE WITH
3-5SM VSBYS & 2000-2800FT CIGS IN MOST AREAS. WITH STRONG LWR-DECK
TROF REMAINING POSITIONED ALONG FRONT RANGE...A BROAD FETCH OF RICH
LWR-DECK MOISTURE CONTINUING TO STREAM N/NW ACROSS KS DICTATES KEEPING
THESE TERMINALS IN MVFR STATUS THROUGHOUT THE AFTERNOON WITH WINDS
INCREASING TO 17-22KTS/20-25MPH SUSTAINED WITH ~30KT/35MPH GUSTS
LIKELY THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 306 AM CST SUN DEC 11 2011/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE PRECIP CHANCES FOR THE TUE-WED TIME
FRAME.
SYNOPSIS:
THE CENTRAL AND SOUTHERN PLAINS ARE IN BETWEEN A SHORTWAVE THAT IS
DEPARTING OFF OF THE EAST COAST AND ANOTHER ONE THAT IS STARTING TO
DIG OFF OF THE WEST COAST. AT THE SURFACE THE RIDGE EXTENDS FROM THE
OHIO VALLEY INTO CENTRAL TX WITH LEE TROUGHING STRENGTHENING OVER
THE NORTHERN HIGH PLAINS. THIS HAS RESULTED IN SW SURFACE WINDS
INCREASING OVERNIGHT.
TODAY-TONIGHT:
DENSE FOG IS EXPECTED TO CONTINUE EARLY THIS MORNING OVER PORTIONS
OF THE FLINT HILLS INTO SE KS. CONFIDENCE IS HIGH THAT THE FOG WILL
NOT LINGER INTO THE LATE MORNING HOURS AND SHOULD LIFT BY 15Z.
JUST LIKE YESTERDAY THE CLOUD FORECAST WILL BE VERY CHALLENGING TODAY
AND WILL PLAY HAVOC WITH TEMPS. SATELLITE CURRENTLY SHOWS A LARGE
AREA OF STRATUS EXTENDING FROM THE TX PANHANDLE INTO SOUTH CENTRAL KS
AND SLOWLY WORKING TO THE NORTHEAST. WHILE WE MAY SEE A FEW BRIEF
BREAKS THIS MORNING...BY THE AFTERNOON HOURS FEEL THAT LOW CLOUDS
WILL ENCOMPASS THE MAJORITY OF THE FORECAST AREA. HOWEVER EVEN WITH
CLOUD COVER...GUSTY SOUTH WINDS WILL WARM ADVECT HIGHER TEMPS INTO
THE AREA WITH ALL LOCATIONS EXPECTED TO BE IN THE 40S TODAY. LOW
LEVEL MOISTURE WILL CONTINUE TO STREAM INTO CENTRAL AND SOUTH
CENTRAL KS TONIGHT WHICH WILL KEEP LOW CLOUDS IN PLACE. WILL GO
AHEAD AND LEAVE SOME DRIZZLE AND LIGHT FOG IN LATE TONIGHT FOR
CENTRAL KS...BUT BECAUSE OF LACK OF LOW LEVEL ISENTROPIC LIFT AND
DEEP SATURATION...NOT TOO IMPRESSED WITH WIDESPREAD HEAVY DRIZZLE
CHANCES.
MON-WED NIGHT:
BY MON AFTERNOON THE UPPER SHORTWAVE WILL BE DIGGING OFF OF THE
SOUTHERN CA COAST. THIS WILL ALLOW MOISTURE TO CONTINUE TO STREAM
INTO THE SOUTHERN AND CENTRAL PLAINS. BY MON NIGHT ISENTROPIC LIFT
AND MOISTURE TRANSPORT WILL INCREASE ENOUGH THAT SOME RAIN SHOWERS
SHOULD DEVELOP. SOMETHING TO KEEP AN EYE ON FOR LATER SHIFTS WILL BE
THE POSITION OF THE COLD FRONT FOR THE LATE MON NIGHT TIME FRAME.
THE NAM IS QUITE A BIT FURTHER SOUTH WITH THIS FRONT COMPARED TO THE
GFS AND ECMWF. IF THE NAM VERIFIES THERE MAY BE A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR FREEZING DRIZZLE OVER CENTRAL KS. HOWEVER
SINCE THE NAM IS CURRENTLY THE OUTLIER...WILL LEAVE TEMPS ON MON
NIGHT OVER CENTRAL KS JUST ABOVE FREEZING.
THE UPPER WAVE IS EXPECTED TO QUICKLY APPROACH THE SOUTHERN PLAINS
ON TUE NIGHT INTO WED. THIS IS WHEN WE CURRENTLY HAVE THE HIGHEST
CONFIDENCE IN MUCH OF THE AREA SEEING RAINFALL AS THE UPPER DYNAMICS
DIRECTLY IMPACT THE AREA. CURRENTLY EXPECTING PRECIP CHANCES TO END
VERY QUICKLY WED NIGHT WITH MOST OF THE FORECAST AREA DRY BY EARLY
THU MORNING. THE PROGRESSIVE NATURE OF THIS SYSTEM DOES NOT ALLOW
ANY OF THE HIGHER THETA-E AIR TO BE WRAPPED AROUND THE BACKSIDE OF
THE LOW WHERE IT COULD INTERACT WITH THE COLDER AIR. THEREFORE
STILL NOT EXPECTING ANY WIDESPREAD HAZARDOUS WINTER WEATHER THROUGH
THIS TIME PERIOD.
THU-SUN:
BY THU AFTERNOON THIS WAVE WILL BE AFFECTING THE EASTERN SEABOARD AS
ANOTHER UPPER IMPULSE DIVES OVER THE GREAT LAKES REGION. THIS WILL
RESULT IN SURFACE HIGH PRESSURE SETTLING OVER THE CENTRAL AND
SOUTHERN PLAINS THROUGH FRI. BOTH THE GFS AND ECMWF AGREE ON
DEVELOPING ANOTHER UPPER LOW OVER SOUTHERN CA BY FRI AFTERNOON AND
IS EXPECTED TO REMAIN OVER THE DESERT SOUTHWEST THROUGH THE WEEKEND.
LAWSON
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VERY TOUGH FORECAST WITH 00Z MODELS CONTINUING TO STRUGGLE WITH
LOW LEVEL MOISTURE. LATEST RUC DOES NOT APPEAR TO BE AS GOOD AS
EARLIER RUNS...SO THE OVERNIGHT PART OF THE FORECAST PRIMARILY
BASED ON OBSERVATIONS/TRENDS AND BEST ESTIMATE OF HOW CONDITIONS
WILL EVOLVE. WORST CONDITIONS HAVE BEEN OCCURRING ON EDGES OF
STRATUS SO FAR THIS EVENING. ANTICIPATE THAT STRATUS/PATCHY DENSE
FOG WILL INCREASE OVER VIRTUALLY ENTIRE AREA OVER THE NEXT FEW
HOURS...AS WEAK SOUTH FLOW ADVECTING SLIGHTLY WARMER/MOISTER AIR
UPSLOPE INTO CHILLED AND SATURATED AIRMASS. NOD IS GIVEN TO THE
NAM WHICH STILL SUGGEST INFLUX OF 850MB-700MB MOISTURE MID TO LATE
MORNING...WHICH WILL LIKELY KEEP MANY AREAS OVERCAST THROUGHOUT
THE PERIOD. EXCEPTION MAY BE SOUTHEAST KS ONCE AGAIN...BUT DO
EXPECT MOISTURE TO ARRIVE THERE BY LATE AFTERNOON. IF THE 850MB-
700MB MOISTURE ARRIVES PRIOR TO BURNING THROUGH THE VERY LOW
CLOUDS...COULD BE STUCK IN IFR THROUGHOUT MOST/ALL DAY. APPEARS
THAT KRSL/KHUT/KSLN WILL SEE MORE MVFR OR IFR CONDITIONS DEVELOP
DURING THE EVENING. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 46 35 48 36 / 10 10 10 20
HUTCHINSON 44 35 47 35 / 10 10 10 20
NEWTON 44 34 48 36 / 10 10 10 20
ELDORADO 45 35 48 36 / 10 10 10 20
WINFIELD-KWLD 47 36 49 37 / 10 10 10 30
RUSSELL 43 33 44 33 / 10 10 10 20
GREAT BEND 45 34 45 34 / 10 10 10 20
SALINA 46 35 46 34 / 10 10 10 20
MCPHERSON 44 35 47 35 / 10 10 10 20
COFFEYVILLE 48 35 48 37 / 10 10 10 30
CHANUTE 46 34 48 36 / 10 10 10 30
IOLA 45 34 48 36 / 10 10 10 30
PARSONS-KPPF 47 34 48 37 / 10 10 10 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR KSZ070>072-
094>096-098.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
306 AM CST SUN DEC 11 2011
.DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE PRECIP CHANCES FOR THE TUE-WED TIME
FRAME.
SYNOPSIS:
THE CENTRAL AND SOUTHERN PLAINS ARE IN BETWEEN A SHORTWAVE THAT IS
DEPARTING OFF OF THE EAST COAST AND ANOTHER ONE THAT IS STARTING TO
DIG OFF OF THE WEST COAST. AT THE SURFACE THE RIDGE EXTENDS FROM THE
OHIO VALLEY INTO CENTRAL TX WITH LEE TROUGHING STRENGTHENING OVER
THE NORTHERN HIGH PLAINS. THIS HAS RESULTED IN SW SURFACE WINDS
INCREASING OVERNIGHT.
TODAY-TONIGHT:
DENSE FOG IS EXPECTED TO CONTINUE EARLY THIS MORNING OVER PORTIONS
OF THE FLINT HILLS INTO SE KS. CONFIDENCE IS HIGH THAT THE FOG WILL
NOT LINGER INTO THE LATE MORNING HOURS AND SHOULD LIFT BY 15Z.
JUST LIKE YESTERDAY THE CLOUD FORECAST WILL BE VERY CHALLENGING TODAY
AND WILL PLAY HAVOC WITH TEMPS. SATELLITE CURRENTLY SHOWS A LARGE
AREA OF STRATUS EXTENDING FROM THE TX PANHANDLE INTO SOUTH CENTRAL KS
AND SLOWLY WORKING TO THE NORTHEAST. WHILE WE MAY SEE A FEW BRIEF
BREAKS THIS MORNING...BY THE AFTERNOON HOURS FEEL THAT LOW CLOUDS
WILL ENCOMPASS THE MAJORITY OF THE FORECAST AREA. HOWEVER EVEN WITH
CLOUD COVER...GUSTY SOUTH WINDS WILL WARM ADVECT HIGHER TEMPS INTO
THE AREA WITH ALL LOCATIONS EXPECTED TO BE IN THE 40S TODAY. LOW
LEVEL MOISTURE WILL CONTINUE TO STREAM INTO CENTRAL AND SOUTH
CENTRAL KS TONIGHT WHICH WILL KEEP LOW CLOUDS IN PLACE. WILL GO
AHEAD AND LEAVE SOME DRIZZLE AND LIGHT FOG IN LATE TONIGHT FOR
CENTRAL KS...BUT BECAUSE OF LACK OF LOW LEVEL ISENTROPIC LIFT AND
DEEP SATURATION...NOT TOO IMPRESSED WITH WIDESPREAD HEAVY DRIZZLE
CHANCES.
MON-WED NIGHT:
BY MON AFTERNOON THE UPPER SHORTWAVE WILL BE DIGGING OFF OF THE
SOUTHERN CA COAST. THIS WILL ALLOW MOISTURE TO CONTINUE TO STREAM
INTO THE SOUTHERN AND CENTRAL PLAINS. BY MON NIGHT ISENTROPIC LIFT
AND MOISTURE TRANSPORT WILL INCREASE ENOUGH THAT SOME RAIN SHOWERS
SHOULD DEVELOP. SOMETHING TO KEEP AN EYE ON FOR LATER SHIFTS WILL BE
THE POSITION OF THE COLD FRONT FOR THE LATE MON NIGHT TIME FRAME.
THE NAM IS QUITE A BIT FURTHER SOUTH WITH THIS FRONT COMPARED TO THE
GFS AND ECMWF. IF THE NAM VERIFIES THERE MAY BE A BRIEF PERIOD OF
LIGHT FREEZING RAIN OR FREEZING DRIZZLE OVER CENTRAL KS. HOWEVER
SINCE THE NAM IS CURRENTLY THE OUTLIER...WILL LEAVE TEMPS ON MON
NIGHT OVER CENTRAL KS JUST ABOVE FREEZING.
THE UPPER WAVE IS EXPECTED TO QUICKLY APPROACH THE SOUTHERN PLAINS
ON TUE NIGHT INTO WED. THIS IS WHEN WE CURRENTLY HAVE THE HIGHEST
CONFIDENCE IN MUCH OF THE AREA SEEING RAINFALL AS THE UPPER DYNAMICS
DIRECTLY IMPACT THE AREA. CURRENTLY EXPECTING PRECIP CHANCES TO END
VERY QUICKLY WED NIGHT WITH MOST OF THE FORECAST AREA DRY BY EARLY
THU MORNING. THE PROGRESSIVE NATURE OF THIS SYSTEM DOES NOT ALLOW
ANY OF THE HIGHER THETA-E AIR TO BE WRAPPED AROUND THE BACKSIDE OF
THE LOW WHERE IT COULD INTERACT WITH THE COLDER AIR. THEREFORE
STILL NOT EXPECTING ANY WIDESPREAD HAZARDOUS WINTER WEATHER THROUGH
THIS TIME PERIOD.
THU-SUN:
BY THU AFTERNOON THIS WAVE WILL BE AFFECTING THE EASTERN SEABOARD AS
ANOTHER UPPER IMPULSE DIVES OVER THE GREAT LAKES REGION. THIS WILL
RESULT IN SURFACE HIGH PRESSURE SETTLING OVER THE CENTRAL AND
SOUTHERN PLAINS THROUGH FRI. BOTH THE GFS AND ECMWF AGREE ON
DEVELOPING ANOTHER UPPER LOW OVER SOUTHERN CA BY FRI AFTERNOON AND
IS EXPECTED TO REMAIN OVER THE DESERT SOUTHWEST THROUGH THE WEEKEND.
LAWSON
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VERY TOUGH FORECAST WITH 00Z MODELS CONTINUING TO STRUGGLE WITH
LOW LEVEL MOISTURE. LATEST RUC DOES NOT APPEAR TO BE AS GOOD AS
EARLIER RUNS...SO THE OVERNIGHT PART OF THE FORECAST PRIMARILY
BASED ON OBSERVATIONS/TRENDS AND BEST ESTIMATE OF HOW CONDITIONS
WILL EVOLVE. WORST CONDITIONS HAVE BEEN OCCURRING ON EDGES OF
STRATUS SO FAR THIS EVENING. ANTICIPATE THAT STRATUS/PATCHY DENSE
FOG WILL INCREASE OVER VIRTUALLY ENTIRE AREA OVER THE NEXT FEW
HOURS...AS WEAK SOUTH FLOW ADVECTING SLIGHTLY WARMER/MOISTER AIR
UPSLOPE INTO CHILLED AND SATURATED AIRMASS. NOD IS GIVEN TO THE
NAM WHICH STILL SUGGEST INFLUX OF 850MB-700MB MOISTURE MID TO LATE
MORNING...WHICH WILL LIKELY KEEP MANY AREAS OVERCAST THROUGHOUT
THE PERIOD. EXCEPTION MAY BE SOUTHEAST KS ONCE AGAIN...BUT DO
EXPECT MOISTURE TO ARRIVE THERE BY LATE AFTERNOON. IF THE 850MB-
700MB MOISTURE ARRIVES PRIOR TO BURNING THROUGH THE VERY LOW
CLOUDS...COULD BE STUCK IN IFR THROUGHOUT MOST/ALL DAY. APPEARS
THAT KRSL/KHUT/KSLN WILL SEE MORE MVFR OR IFR CONDITIONS DEVELOP
DURING THE EVENING. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 46 35 48 36 / 10 10 10 20
HUTCHINSON 44 35 47 35 / 10 10 10 20
NEWTON 44 34 48 36 / 10 10 10 20
ELDORADO 45 35 48 36 / 10 10 10 20
WINFIELD-KWLD 47 36 49 37 / 10 10 10 30
RUSSELL 43 33 44 33 / 10 10 10 20
GREAT BEND 45 34 45 34 / 10 10 10 20
SALINA 46 35 46 34 / 10 10 10 20
MCPHERSON 44 35 47 35 / 10 10 10 20
COFFEYVILLE 48 35 48 37 / 10 10 10 30
CHANUTE 46 34 48 36 / 10 10 10 30
IOLA 45 34 48 36 / 10 10 10 30
PARSONS-KPPF 47 34 48 37 / 10 10 10 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR KSZ070>072-
094>096-098.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1138 PM CST SAT DEC 10 2011
.UPDATE...
VERY TOUGH FORECAST WITH 00Z MODELS CONTINUING TO STRUGGLE WITH
LOW LEVEL MOISTURE. LATEST RUC DOES NOT APPEAR TO BE AS GOOD AS
EARLIER RUNS...SO THE OVERNIGHT PART OF THE FORECAST PRIMARILY
BASED ON OBSERVATIONS/TRENDS AND BEST ESTIMATE OF HOW CONDITIONS
WILL EVOLVE. WORST CONDITIONS HAVE BEEN OCCURRING ON EDGES OF
STRATUS SO FAR THIS EVENING. ANTICIPATE THAT STRATUS/PATCHY DENSE
FOG WILL INCREASE OVER VIRTUALLY ENTIRE AREA OVER THE NEXT FEW
HOURS...AS WEAK SOUTH FLOW ADVECTING SLIGHTLY WARMER/MOISTER AIR
UPSLOPE INTO CHILLED AND SATURATED AIRMASS. NOD IS GIVEN TO THE
NAM WHICH STILL SUGGEST INFLUX OF 850MB-700MB MOISTURE MID TO LATE
MORNING...WHICH WILL LIKELY KEEP MANY AREAS OVERCAST THROUGHOUT
THE PERIOD. EXCEPTION MAY BE SOUTHEAST KS ONCE AGAIN...BUT DO
EXPECT MOISTURE TO ARRIVE THERE BY LATE AFTERNOON. IF THE 850MB-
700MB MOISTURE ARRIVES PRIOR TO BURNING THROUGH THE VERY LOW
CLOUDS...COULD BE STUCK IN IFR THROUGHOUT MOST/ALL DAY. APPEARS
THAT KRSL/KHUT/KSLN WILL SEE MORE MVFR OR IFR CONDITIONS DEVELOP
DURING THE EVENING. -HOWERTON
&&
.PREV DISCUSSION... /ISSUED 545 PM CST SAT DEC 10 2011/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VERY TOUGH FORECAST WITH MOST MODELS CONTINUE TO STRUGGLE WITH LOW
LEVEL MOISTURE. AREA OF IFR CONDITIONS APPEARS TO BE EXPANDING
ONCE AGAIN...AND BELIEVE THIS WILL LIKELY PERSIST OVERNIGHT. RUC
IS CLOSEST...AND IT SUGGESTS CONTINUE EXPANSION OVER ENTIRE AREA
THROUGH 0900 UTC. GIVEN TEMPERATURE/DEWPOINT SPREADS...1-3SM BR
LIKELY DURING THE NIGHT AT MOST LOCATIONS...ALTHOUGH KCNU
CONCEIVEABLY COULD GO LIFR IN FOG. BOTH NAM/GFS SUGGEST INFLUX OF
850MB-700MB MOISTURE MID TO LATE MORNING...WHICH WILL LIKELY KEEP
MANY AREAS OVERCAST THROUGHOUT THE PERIOD. EXCEPTION MAY BE
SOUTHEAST KS ONCE AGAIN...BUT DO EXPECT MOISTURE TO ARRIVE THERE
BY LATE AFTERNOON. IF THE 850MB-700MB MOISTURE ARRIVES PRIOR TO
BURNING THROUGH THE IFR DECK...SITES COULD BE STUCK IN IFR
THROUGHOUT MOST/ALL DAY. -HOWERTON
PREV DISCUSSION... /ISSUED 333 PM CST SAT DEC 10 2011/
DISCUSSION...
MAIN CONCERN WILL BE STRATUS/FOG TONIGHT INTO SUN...THEN CHANCE OF
SHOWERS FOR TUE THROUGH THU.
TONIGHT:
SFC WINDS HAVE GRADUALLY SHIFTED AROUND TO THE SW TODAY AS THE UPPER
FLOW BECOMES MORE ZONAL. THIS RETURN FLOW HAS ALSO ADVECTED IN A LOW
CLOUD DECK FROM THE PANHANDLE OF TX/OK INTO SOUTH CENTRAL KS...WITH
THIS LOW CLOUD DECK EXPECTED TO BE PROBLEMATIC THIS EVE/TONIGHT.
NONE OF THE SHORT TERM MODELS ARE HANDLING THIS CLOUD DECK
WELL...BUT NOT REAL SURE WE WILL SEE THIS DECK DISSIPATE MUCH
OVERNIGHT...AS WEAK WARM ADVECTION CONTINUES ACROSS THE AREA..WITH
LITTLE OR NO MIXING. COULD ALSO SEE SOME PATCHY FOG ASSOCIATED WITH
IT...AS LOW LEVEL MOISTURE REMAINS TRAPPED UNDER THE CLOUD DECK..SO
WILL MENTION THIS AS WELL.
SUN-MON:
FAIRLY CERTAIN STRATUS DECK WILL BE AROUND ON SUN...WHICH WILL KEEP
MAX TEMPS DOWN SOME...BUT WEAK WARM ADVECTION WILL LEAD TO TEMPS A
LITTLE WARMER THAN TODAY. NAM/WRF AND GFS SEEM TO HAVE A LITTLE
BETTER HANDLE ON CLOUDS AND POSSIBLE DRIZZLE/FOG FOR SUN
NIGHT...ESPECIALLY ACROSS CEN KS. WILL HAVE TO KEEP A CLOSE EYE ON
TEMPS NORTH OF INTERSTATE 70...AS THIS AREA MAY SEE TEMPS HOVER NEAR
FREEZING...WHICH COULD LEAD TO FREEZING DRIZZLE THREAT. FOR NOW
THINK WEAK WARM ADVECTION WILL KEEP TEMPS JUST ABOVE FREEZING AND
ALL LIQUID. CERTAINLY LOOKS LIKE A GREY COOL DAY FOR MOST AREAS ON
SUN INTO MON. COULD ALSO SEE SOME OF THIS DRIZZLE REMAIN ACROSS MOST
OF CEN KS EARLY ON MON AS WELL.
TUE-THU:
MODELS STILL DIFFER ON HOW THE SHORTWAVE...THAT WILL BE CENTERED IN
THE SW US...WILL LIFT OUT INTO THE PLAINS FOR THE MIDDLE OF THE
WEEK. BOTH THE GFS AND ECMWF HAVE BEEN CONSISTENT IN STICKING WITH
THEIR DIFFERING SOLUTIONS. WITH THE ECMWF MORE PROGRESSIVE...WHILE
THE GFS IS DEEPER/STRONGER AND HAS MORE NEGATIVE TILT AS IT COMES
INTO THE PLAINS. WITH THAT SAID...THE LATEST ECMWF MY BE TRENDING
TOWARDS THE FURTHER SOUTH GFS SOLUTION. TIMING OF THE SYSTEM IN THE
TWO MODELS SEEMS TO BE THE THING THEY AGREE ON THE MOST...WITH THE
CONTINUED LOW LEVEL MOISTURE RETURN AND WARM ADVECTION EXPECTED TO
LEAD TO A CHANCE OF LIGHT RAIN FOR MOST OF THE AREA TUE. THE MAIN
PRECIP SHOW STILL LOOKS TO BE ON WED...AS SYNOPTIC LIFT FROM THE
MAIN SHORTWAVE LIFTS NORTHEAST ACROSS THE PLAINS...WITH LOTS OF LIFT
AND MOISTURE AROUND FOR A SOLID SHOWER CHANCE...FOR MOST AREAS. WILL
CONTINUE TO MENTION A FEW RUMBLES OF THUNDER ACROSS SRN/SERN KS AS
THIS SYSTEM MOVES THROUGH...WITH ALL THE PRECIP IN THE FORM OF
LIQUID. SYSTEM WILL MAKE ITS WAYS TO THE EAST OF THE AREA FOR LATE
WED NIGHT WITH COLDER AIR FILTERING INTO THE AREA FOR THU.
REST OF THE EXTENDED:
SOME UNCERTAINTY ON HOW THE BEGINNING OF THE WEEKEND WILL PLAY
OUT...WITH THE GFS DROPPING A COLD CANADIAN AIRMASS INTO THE AREA.
BUT THE ECMWF SHOWS QUITE A BAROCLINIC ZONE ACROSS THE AREA FOR
FRI...WHICH COULD LEAD TO A LIGHT SNOW CHANCE. MODEL CONSENSUS
SUGGESTS KEEPING THIS CHANCE IN FOR NOW.
KETCHAM
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
IFR CIGS CONTINUE TO IMPACT MUCH OF THE AREA EARLY THIS AFTERNOON
AND RECENT SATELLITE TRENDS SUPPORT THIS AREA EXPANDING TO INCLUDE
ALL TERMINALS WITH THE EXCEPTION OF KCNU. BY 20-21Z...LOW CLOUDS MAY
START TO BECOME SCATTERED BUT MVFR/IFR MAY RAPIDLY RETURN THIS
EVENING WITH LIGHT SOUTHERLY WINDS AND VERY LOW TEMPERATURE-
DEWPOINT SPREADS. THE LATEST HRRR SUPPORTS MAINTAINING LOW CIGS
AND REDUCTIONS IN VISIBILITY INTO THE OVERNIGHT HOURS AND UPCOMING
AMENDMENTS MAY BECOME NECESSARY AS CONFIDENCE INCREASES.
MCGUIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 26 46 35 49 / 0 10 10 10
HUTCHINSON 26 44 34 50 / 0 10 10 10
NEWTON 26 43 35 47 / 0 10 10 10
ELDORADO 27 45 35 47 / 0 10 10 10
WINFIELD-KWLD 27 47 35 49 / 0 10 10 10
RUSSELL 23 43 34 47 / 0 10 10 10
GREAT BEND 24 45 34 48 / 0 10 10 10
SALINA 25 46 35 48 / 0 10 10 10
MCPHERSON 26 44 34 48 / 0 10 10 10
COFFEYVILLE 27 48 33 46 / 0 10 10 10
CHANUTE 26 46 34 45 / 0 0 10 10
IOLA 26 45 34 45 / 0 0 10 10
PARSONS-KPPF 26 47 34 45 / 0 0 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1130 PM CST SAT DEC 10 2011
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
SATELLITE LOOP INDICATING STATUS STARTING TO SPREAD INTO PARTS OF
SOUTHWEST KANSAS AS OF 05Z. BASED ON EXTRAPOLATION AND THE NEW NAM
AND RUC MODEL SOUNDINGS 015-025 CIGS SHOULD COVER ALL THREE TAF
SITES BY OR SHORTLY AFTER 06Z. THE FOG DEVELOPMENT HOWEVER NOW
DOES NOT LOOK AS FAVORABLE AS PREVIOUSLY THOUGHT. AREAS OF FOG
STILL WILL BE LIKELY BUT DENSE FOG NOW APPEARS TO BE MORE PATCHY
IN NATURE.
AFTER DAYBREAK THE 25-35KT WINDS FORECASTED TO BE LOCATED JUST
ABOVE THE SURFACE WILL BEGIN TO MIX DOWN AS THE SURFACE AS THE
SURFACE PRESSURE GRADIENT BEGINS TO STRENGTHEN ACROSS SOUTHWEST
KANSAS IN RESPONSE TO FALLING PRESSURES ALONG THE LEE OF THE
ROCKIES. WIND SPEEDS OF AROUND 20 KTS CAN BE EXPECTED AT ALL TAF
SITES BY LATE MORNING. -RB
&&
PREV DISCUSSION... /ISSUED 328 PM CST SAT DEC 10 2011/
DISCUSSION...
DAYS 1-2...
ANOTHER ROUND OF FREEZING FOG IS POSSIBLE AGAIN TONIGHT AS MOISTURE
IS TRANSPORTED FROM THE SOUTH AND SURFACE TEMPERATURES DIP TOWARDS
THE DEW POINT TEMPERATURE. OTHERWISE EXPECT MOSTLY CLEAR SKIES AND
WINDS FROM THE SOUTHWEST AT 5 TO 10 MPH. A DRY UPPER LEVEL SHORTWAVE
WILL MOVE THROUGH THE AREA TOMORROW STRENGTHENING SURFACE LEE
TROUGHING ACROSS EASTERN COLORADO. SOUTH TO SOUTHWEST WINDS AT 15 TO
25 MPH CAN BE EXPECTED ACROSS THE FORECAST AREA WITH SOME GUSTS OVER
35 MPH. LOW LEVEL MOISTURE WILL ALSO INCREASE ACROSS THE AREA
TOMORROW ALLOWING STRATUS TO DEVELOP ACROSS EASTERN PORTIONS OF OUR
FORECAST AREA IN THE AFTERNOON. MOSTLY CLOUDY SKIES WILL BE FOUND
ACROSS THE ENTIRE FORECAST AREA TOMORROW NIGHT INTO MONDAY AS LOW
LEVEL MOISTURE CONTINUES TO BE BROUGHT UP FROM THE GULF OF MEXICO. A
COLD FRONT IS ANTICIPATED TO MOVE THROUGH THE AREA IN THE MORNING
AND A SLIGHT CHANCE OF LIGHT RAIN OR DRIZZLE IS POSSIBLE ACROSS
EASTERN PORTIONS OF THE FORECAST AREA MONDAY AFTERNOON. LOWS TONIGHT
WILL DIP INTO THE MID TO UPPER 20S WITH HIGHS TOMORROW IN THE LOWER
TO MID 40S. LOWS TOMORROW NIGHT WILL BE IN THE LOWER TO MID 30S WITH
HIGHS ON MONDAY RANGING FROM THE LOWER 40S NORTH TO LOWER 50S ACROSS
SOUTH CENTRAL KANSAS.
DAYS 3-7...
IN THE MEDIUM RANGE, AS THE WEEK PROGRESSES THERE WILL BE A LARGE
SCALE UPPER PRESSURE LOW FORM OUT NEAR ARIZONA BY TUESDAY NIGHT.
THE ECMWF, GFS, AND GEM MODELS ALL SHOW THIS UPPER LOW. THE UPPER
LOW IS PROGGED TO BE NEAR SOUTH CENTRAL COLORADO BY 18Z WEDNESDAY.
A SURFACE COLD FRONT WILL LIKELY CROSS SOUTH THROUGH THE CWA ON
TUESDAY, THEN GET PUSHED BACK NORTH AS A WARM FRONT ON WEDNESDAY. A
SURFACE LOW SHOULD FORM IN SOUTHWESTERN KANSAS TUESDAY NIGHT, IN
RESPONSE TO THE APPROACHING UPPER LOW IN COLORADO. THAT LOW WILL
FORM A COLD FRONT TRAILING BACK TO THE SOUTHWEST, WHICH WILL PLOW
EAST-SOUTHEAST THROUGH OUR CWA WEDNESDAY NIGHT. WITH ALL THIS SAID,
WILL BRING IN 20 POPS SHOWERS ON TUESDAY AS THE COLD FRONT DIPS
SOUTH, THEN RAISE POPS INTO THE 40 PERCENT RANGE TUESDAY NIGHT IN
OUR EASTERN 2/3RDS OF THE CWA, BUT 20-30 POPS FOR LIGHT SNOW OR
FREEZING DRIZZLE IN OUR NORTHWEST, AS LOWS WILL DIP INTO THE UPPER
20S NEAR THE SYRACUSE TO SCOTT CITY AREA. ON WEDNESDAY THE BIGGER
SHOW WILL ARRIVE AS THE WARM FRONT PUNCHES NORTH AND THE UPPER
SYNOPTIC LIFT CROSSES OVERHEAD WITH THE PASSAGE OF A SHORT WAVE.
THE CREXTENDED PROCEDURE LOADED 60 POPS IN OUR SOUTHEAST WEDNESDAY
WHERE THE MOISTURE WILL BE HIGHEST, 30-40 CHANCE POPS FROM WAKEENEY
TO DODGE TO LIBERAL, AND LOWER 20 POPS IN OUR FAR WEST. THE
CONVECTIVE PARAMETERS LOOK CLOSE, SO IN OUR EAST AND SOUTHEAST, PUT
IN A PRECIPITATION TYPE OF THUNDERSTORMS. THE HIGHEST QPF WILL BE
WEDNESDAY AS WELL, WITH 0.40 INCH AMOUNTS IN OUR SOUTHEAST. THE
PRECIPITATION WILL BE COMING TO AN END FROM WEST TO EAST THURSDAY
NIGHT AS THE SURFACE LOW AND FRONT BOTH EXIT TO OUR EAST.
COLD AIR WILL THEN BE IN PLACE THURSDAY AND THURSDAY NIGHT, WITH AN
UPPER TROUGH PASSING EASTWARD TO THE NORTH OF OUR CWA. THERE COULD
BE SOME LIGHT SNOW IN OUR EXTREME NORTHWEST LATE THURSDAY NIGHT,
THEN THE SLIGHT CHANCE WILL EXIST A BIT FARTHER SOUTHEAST INTO THE
LARNED, DODGE CITY TO LIBERAL AREAS. THIS SHOULD BE VERY LIGHT
SNOW, AND NOT ACCUMULATE AT ALL, THUS THE LOW 20 POPS. THAT UPPER
TROUGH WILL MOVE TO THE PRATT/MEDICINE LODGE AREAS BY FRIDAY NIGHT,
AND 20 POPS WILL BE IN OUR EXTREME EAST.
TEMPERATURES WILL START WITH MAX T`S TUESDAY FROM 37F IN OUR NW TO
49F IN OUR SOUTHEAST. WEDNESDAY SHOULD BE THE WARMEST DAY WITH A
WARM FRONT AND SYNOPTIC SCALE PRECIPITATION AROUND. MAX TEMPS WILL
RANGE WED FROM 46F TO 56F. BY FRIDAY, ONLY EXPECT HIGHS FROM 31F TO
40F, AND SATURDAY EVEN COLDER WITH HIGHS FROM 34F TO 37F. MIN T`S
WILL START TUESDAY IN THE 24F-35F RANGE, WARM TO 30F-43F RANGE
WEDNESDAY, THEN PROGRESSIVELY COOL TO SAT MINS IN THE 16F-23F RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 33 26 43 36 / 0 0 10 10
GCK 38 25 42 32 / 0 0 0 0
EHA 40 26 42 28 / 0 0 0 0
LBL 38 26 43 34 / 0 0 0 0
HYS 35 25 42 34 / 0 0 10 10
P28 34 27 45 37 / 0 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN42/12/12
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1020 PM EST MON DEC 12 2011
.UPDATE...
ISSUED A FREEZING RAIN ADVISORY THROUGH TUE MORNING...SINCE DRIZZLE
WAS FALLING OVER MUCH OF CENTRAL AND WRN UPPER MI WITH TEMPS ALREADY
AT FREEZING INLAND. HARD TO TELL WHEN DRIZZLE WILL STOP...BUT SHOULD
CONTINUE INTO TUE MORNING AS LOW LEVEL MOISTURE HANGS OVER THE
AREA...THE DGZ REMAINS DRY...AND TEMPS SLOWLY FALL TONIGHT.
&&
PREV DISCUSSION...ISSUED AT 639 PM EST MON DEC 12 2011...
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA WITH SRN BRANCH SW FLOW ALF OVER THE GRT LKS BTWN RDG OVER
THE ERN CONUS AND A WRN TROF. A SHRTWV EMBEDDED IN THIS SW FLOW IS
OVER MN AND CAUSING AN AREA OF -RA OVER WI INTO SE UPR MI...WHERE
DEEPER MSTR IS PRESENT. SOME SN IS MIXING IN WITH THIS PCPN IN THE
PRESENCE OF DYNAMIC COOLING ACCOMPANYING THE SHRTWV EVEN THOUGH SFC
TEMPS ARE ABV 32. ISSUED SPS THIS AFTN TO ACCOUNT FOR PERIODS OF
HEAVY SN/SLUSHY ACCUMS IN A SWATH OVER THE CNTRL WHERE DYNAMIC
COOLING RELATED TO AREA OF H85-7 FGEN IS MOST PRONOUNCED. OTRW...
TEMPS OVER THE ENTIRE CWA ARE WELL ABV NORMAL AND IN THE 30S.
ABUNDANT LLVL MSTR WITH DWPTS ALSO IN THE 30S IN LGT SW SFC FLOW HAS
CAUSED QUITE A BIT OF LO CLD/FOG OVER THE CWA...BUT A COLD FNT TO
THE N ASSOCIATED WITH A DISTURBANCE IN THE ARCTIC BRANCH OVER CAN IS
PRESSING SLOWLY SWD INTO LK SUP. THE COLD AIR BEHIND THIS FNT IS
QUITE SHALLOW PER THE 12Z INL RAOB...BUT SFC TEMPS AT NOON FALL
QUITE SHARPLY FM ARND 35 OVER THE KEWEENAW AND AHEAD OF THE FNT TO
19 AT THUNDER BAY ONTARIO.
&&
.SHORT TERM DISCUSSION /TNGT AND TUE/...
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN CHCS/PTYPE ASSOCIATED
WITH SHRTWV LIFTING INTO WI. FOCUS FOR LATER TNGT AND TUE SHIFTS TO
INFLUX OF COLDER/DRIER AIR FM THE N AND IMPACT ON THE WX.
TNGT...SHRTWV OVER WI AND ACCOMPANYING DYNAMICS/DEEPER MSTR ARE
PROGGED TO LIFT OUT AND EXIT THE ERN ZNS BY LATE EVNG...SO GOING
MORE WDSPRD MIXED PCPN OVER MAINLY THE SE HALF WL DIMINISH WITH MID
LVL SUBSIDENCE/DRYING OVERSPREADING THE FA. HOWEVER...INFLUX OF
SHALLOW COLD AIR FOLLOWING NW-SE PASSAGE OF SFC COLD FNT WL MAINTAIN
A SHARP LLVL INVRN AND PRESENT OVC ST/SC DECK. IN PLACES WITH
UPSLOPE WIND FLOW...OPTED TO MAINTAIN MENTION OF -DZ/-FZDZ WITH
SHALLOW MSTR WELL BLO THE DGZ AND UNDER SUBSIDENCE ALF. CONSIDERING
THE LLVL CHILL OBSVD UPSTREAM...TENDED TO GO TOWARD THE LO SIDE OF
GUIDANCE FOR TEMPS FOLLOWING THE COLD FROPA. EVEN SO...AIRMASS WL
NOT BE SUFFICIENTLY COLD TO SUPPORT LES WITH SHARP INVRN.
TUE...SHALLOW COLD WEDGE WL REMAIN IN PLACE WITH SLOWING VEERING
FLOW TO MORE ESE IN THE AFTN AS CENTER OF HI PRES IN ONTARIO DRIFTS
TO THE E. WITH COLD WEDGE GETTING A BIT MORE SHALLOW...SUSPECT
LINGERING -DZ/-FZDZ WL BE MORE TIED TO UPSLOPE FLOW OVER THE NCNTRL
WHERE THERE WL BE ADDITIONAL MOISTENING OFF LK SUP. EXPECT LTL
DIURNAL TEMP RISE WITH LINGERING LO CLD OVC.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
ACTIVE MID TERM PORTION OF THE FORECAST...WITH A LOW PRESSURE SYSTEM
MOVING THROUGH THE AREA AROUND MID WEEK AND PROVIDING A WINTRY MIX
OF PCPN.
TUES NIGHT...UPPER RIDGE AXIS WILL BE SHIFTING E OF THE CWA THROUGH
THE NIGHT. SHOULD KEEP MUCH OF THE AREA DRY...ALTHOUGH PERSISTANT
LOW CLOUDS WILL BE COVERING MUCH OF THE AREA. WITH INCREASING
ISENTROPIC ASCENT AROUND THE 280 SFC AND DRY AIR ABOVE
5KFT...WOULDN/T BE SURPRISED IF THE SWRN HALF OF THE CWA EXPERIENCES
SOME DZ/FZDZ...SO HAVE PUT THE MENTION IN FOR MUCH OF THE NIGHT.
TRANSITIONED TO A RA/SN MIX ALONG THE WI BORDER OVERNIGHT...AS THE
280-300K ISENTROPIC ASCENT BEGINS TO MOVE INTO THE AREA. WITH THE
MOISTURE EATING AWAY AT THE DRY AIR...EXPECT THE DZ/RA TO QUICKLY
TRANSITION TO MAINLY SNOW ALONG THE BORDER AS ICE BECOMES PRESENT
AND THERE IS A NEARLY ISOTHERMAL LAYER AT/BELOW 0C FROM THE SFC TO
6KFT.
WITH THE MAIN TROUGH STILL WELL TO THE SW IN THE FOUR CORNERS
REGION...WEAK SHORTWAVE ENERGY WILL BE EJECTING NE TOWARDS THE AREA
ON WED. THIS WILL PUSH A WEAK LOW PRESSURE TROUGH ACROSS THE CWA
THROUGH THE DAY. BEST CHANCES OF PCPN ARE S AND E...CLOSER TO THE
MAIN PUSH OF THE SHORTWAVE...ALONG WITH H850-700 WAA AND ISENTROPIC
ASCENT. THIS AREA OF PCPN SHOULD QUICKLY MOVE NE THROUGH THE CWA
DURING THE MORNING AND EARLY AFTN AND LEAD TO A SLIGHTLY DRIER
PERIOD OVER THE W IN THE LATE AFTN BEFORE THE NEXT WAVE AFFECTS THE
AREA. DIFFICULTY IN THE FCST COMES FROM PCPN TYPE...AS THERE COULD
BE A MIXED BAG WITH THE PASSAGE OF THE SYSTEM. SOUNDINGS CONTINUE TO
SHOW A NEARLY ISOTHERMAL 0C LAYER FROM SFC TO 7KFT FOR THE
CENTRAL/WRN PORTIONS OF THE AREA...WHICH WOULD SUPPORT SNOW IN THE
MORNING. THEN AS SRLY WINDS INCREASE THROUGH THE DAY...LLVL TEMPS
LOOK TO RISE AND LEAVE THE LOWEST 2-4KFT ABOVE FREEZING /TOWARDS
2-3C/. AT THAT SAME TIME...THE DEEP MOISTURE EXITS THE AREA AND
THERE WILL LIKELY BE LITTLE/NO ICE POTENTIAL IN THE CLOUDS...SO HAVE
WENT MAINLY RAIN...WITH JUST A MENTION OF SNOW OVER THE N. MAY END
UP BEING JUST A -RA/DZ SITUATION IN THE LATE AFTN BEFORE NEXT WAVE
ARRIVES.
MAIN SHORTWAVE FROM THE SW FLOW ARRIVES ON WED NIGHT OVER THE ERN
CWA...WHICH MODELS RESPOND TO BY INTENSIFYING THE LOW OVER THE UPPER
GREAT LAKES. AT THE SAME TIME...NRN STREAM SHORTWAVE BEGINS TO ENTER
THE NRN PLAINS AND PHASES WITH THE SRN STREAM. MODELS HAVE A
NOTORIOUSLY TOUGH TIME WITH THESE EVENTS AND IT APPEARS THAT IT
CONTINUES WITH THIS SITUATION. ISSUES APPEAR WITH THE
TIMING/STRENGTH OF THE NRN STREAM WAVE...WHICH AFFECTS
INTENSITY/TRACK OF LOW. TRENDS IN THE GFS/ECMWF OVER THE LAST DAY OR
TWO HAVE BEEN FOR A WEAKER LOW TO TRACK ACROSS THE FAR ERN CWA WITH
A WEAKER NRN STREAM WAVE. WILL FOLLOW THAT TREND FOR THE WED NIGHT
AND THURS FORECAST...WITH AN EMPHASIS ON THE HPC PREFERRED GFS.
THEREFORE...HAVE THE HIGHEST POPS /80 PLUS/ OVER THE ERN HALF OF THE
CWA WITH THE BEST FORCING/MOISTURE. EXPECT THIS TO BE MAINLY RAIN
OVER THE EAST HALF...BUT IF THE ECMWF ENDS UP BEING CORRECT THERE
COULD BE SOME MIXING LATE.
FCST IS A LITTLE MORE TRICKY OVER THE W...SINCE IT IS ON THE FRINGE
OF THE BEST DEEP MOISTURE AND FORCING. IF PCPN OCCURS...HAVE A
FEELING THAT POTENTIAL FOR ICE IN THE CLOUDS IS LIMITED. HAVE
TRENDED TOWARDS MORE OF A RA SITUATION UNTIL THE COLDER AIR ARRIVES
TOWARDS DAYBREAK THURSDAY. DEPENDING ON HOW QUICKLY TEMPS FALL
DURING THE NIGHT AND INTO THURS MORNING...COULD SEE A PERIOD OF FZDZ
BEFORE TURNING TO ALL SNOW DURING THE MORNING.
THE LOW SHOULD THEN INTENSIFY OVER QUEBEC ON THURS...AS THE
SHORTWAVES PHASE. WITH SFC HIGH OVER THE NRN PLAINS AND JUST E OF
THE CANADIAN ROCKIES...EXPECT NW WINDS AND H850 TEMPS NEAR -12C TO
LEAD TO AT LEAST SOME LES DEVELOPING. INVERSION HEIGHTS AROUND
6-8KFT GIVES A DECENT CLOUD DEPTH...BUT WITH BEST FORCING BELOW THE
DGZ WILL LIMIT SNOW GROWTH. OPTED TO BUMP POPS UP HEADING INTO THE
AFTN...AS MORE FAVORABLE CONDITIONS FOR LES ARRIVE...ESPECIALLY
SINCE THE NRN CWA SHOULD BE SEEING WRAP AROUND MID-LVL MOISTURE FROM
THE LOW. FINALLY...SHOULD BE A BREEZY DAY ON THURS...WITH GUSTS
ALONG THE ERN LK SUPERIOR SHORELINE APPROACHING 40MPH.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
OVERALL...GOOD AGREEMENT IN THE EXTENDED MODELS ON THE OVERALL
PATTERN FOR THE EXTENDED PERIOD. ON THURS NIGHT...UPPER TROUGH WILL
BE PUSHING THROUGH THE AREA AND DROPPING H850 TEMPS TOWARDS -14C.
SHOULD STILL BE SOME MID-LVL MOISTURE OVER THE E BEFORE THE MOISTURE
EXITS THE AREA ON FRI AS THE INVERSION HEIGHTS FALL TOWARDS 5KFT
WITH HIGH PRESSURE RIDGE MOVING OVER THE WRN CWA. THUS...LES
INTENSITY SHOULD HIT IT/S PEAK THURS NIGHT...AS SHOWN IN LES
PARAMETER...BEFORE DIMINISHING IN INTENSITY THROUGH FRI. ONLY MADE
MINOR TWEAKS UP TO THE POPS OVER THE EAST AND THEN BUMPED UP TO HIGH
END CHANCE AND LOW LIKELY/S OVER THE NW WIND SNOW BELTS OVER THE
WEST FOR THURS NIGHT INTO FRI...ALTHOUGH THE CHANCES WILL DIMINISH
OVER THE W IN THE AFTN. IN ADDITION...WEAK SHORTWAVE ON FRI COULD
BRING SOME MID CLOUDS.
SFC HIGH PRESSURE RIDGE WILL QUICKLY MOVE EAST OF THE AREA ON FRI
NIGHT...WITH MODELS CONSISTENT ON A SHORTWAVE MOVING THROUGH THE
UPPER MISS VALLEY ON SAT. THIS WAVE WILL LIKELY DIVE S OF THE
CWA...AND CARRY THE BEST MOISTURE AND H850-500 Q-VECTOR CONV WITH
IT. OTHER THAN LINGERING LES OVER THE NW FAVORED LOCATIONS OVER THE
E IN THE MORNING BEFORE WIND SHIFT TO THE SW...WILL KEEP THE REST OF
THE CWA DRY.
UPPER RIDGE MOVING THROUGH SUNDAY...WITH H850 TEMPS RISING TOWARDS
1-4C. SHOULD LEAD TO ANOTHER WARM SUNDAY ACROSS THE AREA...BUT MAY
NOT BE QUITE AS WARM AS YESTERDAY/S HIGHS. DID BUMP UP TEMPS FROM
THE CONSENSUS OVER THE DOWNSLOPE AREAS NEAR LK SUPERIOR INTO THE
UPPER 30S. NEXT TROUGH WILL AFFECT THE AREA SUN NIGHT INTO
MON...BRINGING ANOTHER CHANCE OF PCPN TO THE AREA. DIFFERENCES IN
HOW AMPLIFIED THE TROUGH IS...ALONG WITH MOISTURE RETURN FROM THE
GULF...SO WILL LEAVE POPS AT SLIGHT/CHANCES.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
LITTLE CHANGE FROM THE 18Z TAFS. EXPECT PREDOMINANT IFR/LIFR
CONDITIONS AT ALL 3 SITES THIS FCST PERIOD WITH MOIST SW FLOW AHEAD
OF A SLOW MOVING COLD FNT APRCHG FM THE N. ALTHOUGH THE FNT WILL
SINK SLOWLY S OVER THE FA LATER TDAY/ TNGT...SHALLOW INFLUX OF COLD
AIR FM THE N THAT SHARPENS LLVL INVRN WL MAINTAIN THE LO CLDS. THE
BEST CHC FOR IMPROVEMENT TO MVFR TONIGHT WL BE AT CMX...AS SOME LLVL
DRYING BEHIND THE FNT MIGHT IMPACT THE KEWEENAW WITH LESS OF AN
UPSLOPE WIND COMPONENT AT TIMES TNGT. SOME -FZDZ MAY IMPACT ALL 3
SITES AT TIMES WHEN THE LLVL WINDS ARE UPSLOPE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO EARLY WED AS A
LOW PRESSURE TROUGH SLOWLY SLIDES ACROSS LK SUPERIOR. WINDS BECOME
MORE SOUTHERLY AS ANOTHER LO PRES SYSTEM DEVELOPING IN THE PLAINS
BEGINS TO LIFT TOWARD THE UPPER GREAT LAKES. SE WINDS AHEAD OF THIS
LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF ON WED. THE
MAIN HAZARD WILL BE AFTER THE LOW MOVES TOWARD QUEBEC ON THU...WHEN
NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING
WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE
SLOW APPROACH OF HI PRES. A STRONGER WSW FLOW WILL REDEVELOP ON SAT
AFTER THIS HI SHIFTS TO THE SE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL NOON EST /11 AM CST/ TUESDAY FOR
MIZ002-004>006-009>013-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TITUS
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...SRF
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
639 PM EST MON DEC 12 2011
UPDATED AVIATION DISCUSSION FOR 00Z TAFS
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA WITH SRN BRANCH SW FLOW ALF OVER THE GRT LKS BTWN RDG OVER
THE ERN CONUS AND A WRN TROF. A SHRTWV EMBEDDED IN THIS SW FLOW IS
OVER MN AND CAUSING AN AREA OF -RA OVER WI INTO SE UPR MI...WHERE
DEEPER MSTR IS PRESENT. SOME SN IS MIXING IN WITH THIS PCPN IN THE
PRESENCE OF DYNAMIC COOLING ACCOMPANYING THE SHRTWV EVEN THOUGH SFC
TEMPS ARE ABV 32. ISSUED SPS THIS AFTN TO ACCOUNT FOR PERIODS OF
HEAVY SN/SLUSHY ACCUMS IN A SWATH OVER THE CNTRL WHERE DYNAMIC
COOLING RELATED TO AREA OF H85-7 FGEN IS MOST PRONOUNCED. OTRW...
TEMPS OVER THE ENTIRE CWA ARE WELL ABV NORMAL AND IN THE 30S.
ABUNDANT LLVL MSTR WITH DWPTS ALSO IN THE 30S IN LGT SW SFC FLOW HAS
CAUSED QUITE A BIT OF LO CLD/FOG OVER THE CWA...BUT A COLD FNT TO
THE N ASSOCIATED WITH A DISTURBANCE IN THE ARCTIC BRANCH OVER CAN IS
PRESSING SLOWLY SWD INTO LK SUP. THE COLD AIR BEHIND THIS FNT IS
QUITE SHALLOW PER THE 12Z INL RAOB...BUT SFC TEMPS AT NOON FALL
QUITE SHARPLY FM ARND 35 OVER THE KEWEENAW AND AHEAD OF THE FNT TO
19 AT THUNDER BAY ONTARIO.
&&
.SHORT TERM DISCUSSION /TNGT AND TUE/...
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN CHCS/PTYPE ASSOCIATED
WITH SHRTWV LIFTING INTO WI. FOCUS FOR LATER TNGT AND TUE SHIFTS TO
INFLUX OF COLDER/DRIER AIR FM THE N AND IMPACT ON THE WX.
TNGT...SHRTWV OVER WI AND ACCOMPANYING DYNAMICS/DEEPER MSTR ARE
PROGGED TO LIFT OUT AND EXIT THE ERN ZNS BY LATE EVNG...SO GOING
MORE WDSPRD MIXED PCPN OVER MAINLY THE SE HALF WL DIMINISH WITH MID
LVL SUBSIDENCE/DRYING OVERSPREADING THE FA. HOWEVER...INFLUX OF
SHALLOW COLD AIR FOLLOWING NW-SE PASSAGE OF SFC COLD FNT WL MAINTAIN
A SHARP LLVL INVRN AND PRESENT OVC ST/SC DECK. IN PLACES WITH
UPSLOPE WIND FLOW...OPTED TO MAINTAIN MENTION OF -DZ/-FZDZ WITH
SHALLOW MSTR WELL BLO THE DGZ AND UNDER SUBSIDENCE ALF. CONSIDERING
THE LLVL CHILL OBSVD UPSTREAM...TENDED TO GO TOWARD THE LO SIDE OF
GUIDANCE FOR TEMPS FOLLOWING THE COLD FROPA. EVEN SO...AIRMASS WL
NOT BE SUFFICIENTLY COLD TO SUPPORT LES WITH SHARP INVRN.
TUE...SHALLOW COLD WEDGE WL REMAIN IN PLACE WITH SLOWING VEERING
FLOW TO MORE ESE IN THE AFTN AS CENTER OF HI PRES IN ONTARIO DRIFTS
TO THE E. WITH COLD WEDGE GETTING A BIT MORE SHALLOW...SUSPECT
LINGERING -DZ/-FZDZ WL BE MORE TIED TO UPSLOPE FLOW OVER THE NCNTRL
WHERE THERE WL BE ADDITIONAL MOISTENING OFF LK SUP. EXPECT LTL
DIURNAL TEMP RISE WITH LINGERING LO CLD OVC.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
ACTIVE MID TERM PORTION OF THE FORECAST...WITH A LOW PRESSURE SYSTEM
MOVING THROUGH THE AREA AROUND MID WEEK AND PROVIDING A WINTRY MIX
OF PCPN.
TUES NIGHT...UPPER RIDGE AXIS WILL BE SHIFTING E OF THE CWA THROUGH
THE NIGHT. SHOULD KEEP MUCH OF THE AREA DRY...ALTHOUGH PERSISTANT
LOW CLOUDS WILL BE COVERING MUCH OF THE AREA. WITH INCREASING
ISENTROPIC ASCENT AROUND THE 280 SFC AND DRY AIR ABOVE
5KFT...WOULDN/T BE SURPRISED IF THE SWRN HALF OF THE CWA EXPERIENCES
SOME DZ/FZDZ...SO HAVE PUT THE MENTION IN FOR MUCH OF THE NIGHT.
TRANSITIONED TO A RA/SN MIX ALONG THE WI BORDER OVERNIGHT...AS THE
280-300K ISENTROPIC ASCENT BEGINS TO MOVE INTO THE AREA. WITH THE
MOISTURE EATING AWAY AT THE DRY AIR...EXPECT THE DZ/RA TO QUICKLY
TRANSITION TO MAINLY SNOW ALONG THE BORDER AS ICE BECOMES PRESENT
AND THERE IS A NEARLY ISOTHERMAL LAYER AT/BELOW 0C FROM THE SFC TO
6KFT.
WITH THE MAIN TROUGH STILL WELL TO THE SW IN THE FOUR CORNERS
REGION...WEAK SHORTWAVE ENERGY WILL BE EJECTING NE TOWARDS THE AREA
ON WED. THIS WILL PUSH A WEAK LOW PRESSURE TROUGH ACROSS THE CWA
THROUGH THE DAY. BEST CHANCES OF PCPN ARE S AND E...CLOSER TO THE
MAIN PUSH OF THE SHORTWAVE...ALONG WITH H850-700 WAA AND ISENTROPIC
ASCENT. THIS AREA OF PCPN SHOULD QUICKLY MOVE NE THROUGH THE CWA
DURING THE MORNING AND EARLY AFTN AND LEAD TO A SLIGHTLY DRIER
PERIOD OVER THE W IN THE LATE AFTN BEFORE THE NEXT WAVE AFFECTS THE
AREA. DIFFICULTY IN THE FCST COMES FROM PCPN TYPE...AS THERE COULD
BE A MIXED BAG WITH THE PASSAGE OF THE SYSTEM. SOUNDINGS CONTINUE TO
SHOW A NEARLY ISOTHERMAL 0C LAYER FROM SFC TO 7KFT FOR THE
CENTRAL/WRN PORTIONS OF THE AREA...WHICH WOULD SUPPORT SNOW IN THE
MORNING. THEN AS SRLY WINDS INCREASE THROUGH THE DAY...LLVL TEMPS
LOOK TO RISE AND LEAVE THE LOWEST 2-4KFT ABOVE FREEZING /TOWARDS
2-3C/. AT THAT SAME TIME...THE DEEP MOISTURE EXITS THE AREA AND
THERE WILL LIKELY BE LITTLE/NO ICE POTENTIAL IN THE CLOUDS...SO HAVE
WENT MAINLY RAIN...WITH JUST A MENTION OF SNOW OVER THE N. MAY END
UP BEING JUST A -RA/DZ SITUATION IN THE LATE AFTN BEFORE NEXT WAVE
ARRIVES.
MAIN SHORTWAVE FROM THE SW FLOW ARRIVES ON WED NIGHT OVER THE ERN
CWA...WHICH MODELS RESPOND TO BY INTENSIFYING THE LOW OVER THE UPPER
GREAT LAKES. AT THE SAME TIME...NRN STREAM SHORTWAVE BEGINS TO ENTER
THE NRN PLAINS AND PHASES WITH THE SRN STREAM. MODELS HAVE A
NOTORIOUSLY TOUGH TIME WITH THESE EVENTS AND IT APPEARS THAT IT
CONTINUES WITH THIS SITUATION. ISSUES APPEAR WITH THE
TIMING/STRENGTH OF THE NRN STREAM WAVE...WHICH AFFECTS
INTENSITY/TRACK OF LOW. TRENDS IN THE GFS/ECMWF OVER THE LAST DAY OR
TWO HAVE BEEN FOR A WEAKER LOW TO TRACK ACROSS THE FAR ERN CWA WITH
A WEAKER NRN STREAM WAVE. WILL FOLLOW THAT TREND FOR THE WED NIGHT
AND THURS FORECAST...WITH AN EMPHASIS ON THE HPC PREFERRED GFS.
THEREFORE...HAVE THE HIGHEST POPS /80 PLUS/ OVER THE ERN HALF OF THE
CWA WITH THE BEST FORCING/MOISTURE. EXPECT THIS TO BE MAINLY RAIN
OVER THE EAST HALF...BUT IF THE ECMWF ENDS UP BEING CORRECT THERE
COULD BE SOME MIXING LATE.
FCST IS A LITTLE MORE TRICKY OVER THE W...SINCE IT IS ON THE FRINGE
OF THE BEST DEEP MOISTURE AND FORCING. IF PCPN OCCURS...HAVE A
FEELING THAT POTENTIAL FOR ICE IN THE CLOUDS IS LIMITED. HAVE
TRENDED TOWARDS MORE OF A RA SITUATION UNTIL THE COLDER AIR ARRIVES
TOWARDS DAYBREAK THURSDAY. DEPENDING ON HOW QUICKLY TEMPS FALL
DURING THE NIGHT AND INTO THURS MORNING...COULD SEE A PERIOD OF FZDZ
BEFORE TURNING TO ALL SNOW DURING THE MORNING.
THE LOW SHOULD THEN INTENSIFY OVER QUEBEC ON THURS...AS THE
SHORTWAVES PHASE. WITH SFC HIGH OVER THE NRN PLAINS AND JUST E OF
THE CANADIAN ROCKIES...EXPECT NW WINDS AND H850 TEMPS NEAR -12C TO
LEAD TO AT LEAST SOME LES DEVELOPING. INVERSION HEIGHTS AROUND
6-8KFT GIVES A DECENT CLOUD DEPTH...BUT WITH BEST FORCING BELOW THE
DGZ WILL LIMIT SNOW GROWTH. OPTED TO BUMP POPS UP HEADING INTO THE
AFTN...AS MORE FAVORABLE CONDITIONS FOR LES ARRIVE...ESPECIALLY
SINCE THE NRN CWA SHOULD BE SEEING WRAP AROUND MID-LVL MOISTURE FROM
THE LOW. FINALLY...SHOULD BE A BREEZY DAY ON THURS...WITH GUSTS
ALONG THE ERN LK SUPERIOR SHORELINE APPROACHING 40MPH.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
OVERALL...GOOD AGREEMENT IN THE EXTENDED MODELS ON THE OVERALL
PATTERN FOR THE EXTENDED PERIOD. ON THURS NIGHT...UPPER TROUGH WILL
BE PUSHING THROUGH THE AREA AND DROPPING H850 TEMPS TOWARDS -14C.
SHOULD STILL BE SOME MID-LVL MOISTURE OVER THE E BEFORE THE MOISTURE
EXITS THE AREA ON FRI AS THE INVERSION HEIGHTS FALL TOWARDS 5KFT
WITH HIGH PRESSURE RIDGE MOVING OVER THE WRN CWA. THUS...LES
INTENSITY SHOULD HIT IT/S PEAK THURS NIGHT...AS SHOWN IN LES
PARAMETER...BEFORE DIMINISHING IN INTENSITY THROUGH FRI. ONLY MADE
MINOR TWEAKS UP TO THE POPS OVER THE EAST AND THEN BUMPED UP TO HIGH
END CHANCE AND LOW LIKELY/S OVER THE NW WIND SNOW BELTS OVER THE
WEST FOR THURS NIGHT INTO FRI...ALTHOUGH THE CHANCES WILL DIMINISH
OVER THE W IN THE AFTN. IN ADDITION...WEAK SHORTWAVE ON FRI COULD
BRING SOME MID CLOUDS.
SFC HIGH PRESSURE RIDGE WILL QUICKLY MOVE EAST OF THE AREA ON FRI
NIGHT...WITH MODELS CONSISTENT ON A SHORTWAVE MOVING THROUGH THE
UPPER MISS VALLEY ON SAT. THIS WAVE WILL LIKELY DIVE S OF THE
CWA...AND CARRY THE BEST MOISTURE AND H850-500 Q-VECTOR CONV WITH
IT. OTHER THAN LINGERING LES OVER THE NW FAVORED LOCATIONS OVER THE
E IN THE MORNING BEFORE WIND SHIFT TO THE SW...WILL KEEP THE REST OF
THE CWA DRY.
UPPER RIDGE MOVING THROUGH SUNDAY...WITH H850 TEMPS RISING TOWARDS
1-4C. SHOULD LEAD TO ANOTHER WARM SUNDAY ACROSS THE AREA...BUT MAY
NOT BE QUITE AS WARM AS YESTERDAY/S HIGHS. DID BUMP UP TEMPS FROM
THE CONSENSUS OVER THE DOWNSLOPE AREAS NEAR LK SUPERIOR INTO THE
UPPER 30S. NEXT TROUGH WILL AFFECT THE AREA SUN NIGHT INTO
MON...BRINGING ANOTHER CHANCE OF PCPN TO THE AREA. DIFFERENCES IN
HOW AMPLIFIED THE TROUGH IS...ALONG WITH MOISTURE RETURN FROM THE
GULF...SO WILL LEAVE POPS AT SLIGHT/CHANCES.
&&
.AVIATION /FOR THE 00Z TAF ISSUANCE/...
LITTLE CHANGE FROM THE 18Z TAFS. EXPECT PREDOMINANT IFR/LIFR
CONDITIONS AT ALL 3 SITES THIS FCST PERIOD WITH MOIST SW FLOW AHEAD
OF A SLOW MOVING COLD FNT APRCHG FM THE N. ALTHOUGH THE FNT WILL
SINK SLOWLY S OVER THE FA LATER TDAY/ TNGT...SHALLOW INFLUX OF COLD
AIR FM THE N THAT SHARPENS LLVL INVRN WL MAINTAIN THE LO CLDS. THE
BEST CHC FOR IMPROVEMENT TO MVFR TONIGHT WL BE AT CMX...AS SOME LLVL
DRYING BEHIND THE FNT MIGHT IMPACT THE KEWEENAW WITH LESS OF AN
UPSLOPE WIND COMPONENT AT TIMES TNGT. SOME -FZDZ MAY IMPACT ALL 3
SITES AT TIMES WHEN THE LLVL WINDS ARE UPSLOPE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO EARLY WED AS A
LOW PRESSURE TROUGH SLOWLY SLIDES ACROSS LK SUPERIOR. WINDS BECOME
MORE SOUTHERLY AS ANOTHER LO PRES SYSTEM DEVELOPING IN THE PLAINS
BEGINS TO LIFT TOWARD THE UPPER GREAT LAKES. SE WINDS AHEAD OF THIS
LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF ON WED. THE
MAIN HAZARD WILL BE AFTER THE LOW MOVES TOWARD QUEBEC ON THU...WHEN
NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING
WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE
SLOW APPROACH OF HI PRES. A STRONGER WSW FLOW WILL REDEVELOP ON SAT
AFTER THIS HI SHIFTS TO THE SE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...SRF
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
340 PM EST SUN DEC 11 2011
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA WITH NRN BRANCH RDGING BLDG INTO THE UPR GRT LKS. THESE
RISING HGTS...WITH 00Z-12Z H3 RISES UP TO 150M AT APX...ARE BEING
FORCED BY VIGOROUS WAD IN THE STRONG WSW FLOW /12Z H85 WIND SPEED AT
INL WAS 50KT/ BTWN SFC-H85 HI PRES IN THE MID ATLANTIC STATES AND LO
PRES JUST N OF THE BORDER MOVING E INTO NW ONTARIO THAT IS
ASSOCIATED WITH A SHRTWV NEAR LK WINNIPEG. THIS STRONG WAD HAS
PUSHED H85 TEMPS IN THE UPR MS VALLEY/GREAT LKS TO UNSEASONABLY HI
LVLS...WITH 12Z H85 TEMPS AT INL/MPX UP TO 7C VS 0C AT APX AND 3C AT
GRB TOWARD THE RETREATING COLD AIR. LO CLDS OVER THE E HALF OF THE
CWA THAT FORMED AS THIS WARMER AIR PUSHED OVER MORE RESILIENT NEAR
SFC COLD AIR IN THE PRESENCE OF RADIATIONAL COOLING LAST NGT ARE
ONLY GRDLY DISSIPATING EARLY THIS AFTN. OTRW...THE OVERALL DRYNESS
OF THE LOCAL 12Z RAOBS IS ALLOWING A MOSUNNY DAY. BUT MORE LO CLDS
ARE PUSHING NEWD THRU IOWA TOWARD THE UPR MIDWEST IN THE SW LLVL
FLOW ARND THE HI IN THE MID ATLANTIC. A DISTURBANCE IN THE SRN
BRANCH FLOW IS NOW IN KANSAS AND MOVING NEWD AS WELL.
&&
.SHORT TERM DISCUSSION /TNGT AND MON/...
MAIN FCST CONCERNS THIS PACKAGE ARE LO CLD TRENDS AND THE POTENTIAL
FOR MIXED PCPN ON MON AS DISTURANCE NOW IN KANSAS RIDES TO THE NE.
TNGT...EXPECT THE LINGERING LO CLDS OVER THE E TO BE GONE BY FCST
ISSUANCE...WITH MOCLR SKIES/WELL ABV NORMAL TEMPS DOMINATING.
ALTHOUGH THE LO CLDS HEADING NE FM IOWA ARE LIKELY TO MIX OUT WITH
DAYTIME TEMPS RISING INTO THE 30S/40S THIS AFTN...EXPECT THE ST/SC
TO REDVLP WITH LOSS OF DAYTIME HEATING AFT SUNSET. 12Z MODEL
GUIDANCE SHOWS THE HIER LLVL RH ARRIVING NEAR THE WI BORDER W OF IMT
THIS EVNG...SO EXPECT EXPANDING LO CLDS SW-NE. THE COMBINATION OF
THE LO CLDS/STEADY SW FLOW OF MILD AIR WL GREATLY REDUCE DIURNAL
FALL OF TEMPS...BUT MIN TEMPS WL STILL FALL BLO 32 EVERYWHERE.
LOCATIONS NEAR LK SUP WHERE THE SW FLOW DOWNSLOPES WL BE WARMEST.
OPTED TO RETAIN MENTION OF SOME -FZDZ OVER THE INTERIOR W LATE AWAY
FM THE DOWNSLOPING NEAR LK SUP AS SHALLOW MSTR INFLUX GROWS A BIT
DEEPER WITH SOME DPVA/OMEGA/DEEPER MSTR ADVCTN AHEAD OF APRCHG
KANSAS SHRTWV. BUT SINCE THE HIER RH WL REMAIN WELL BLO THE DGZ AND
STILL BE RELATIVELY SHALLOW /BLO ABOUT H85/...ANY PCPN SHOULD REMAIN
IN THE FORM OF SMALL WATER DROPLETS.
MON...COMBINATION OF ARRIVAL OF LO PRES TROF ATTENDANT TO SHRTWV/SFC
LO NOW IN NW ONTARIO...DEEPER MSTR FM THE SW...AND SHRTWV NOW IN
KANSAS/ACCOMPANYING DYNAMICS WL RESULT IN EXPANDING PCPN CHCS. THE
12Z NAM/GFS/LOCAL WRF-ARW RUNS ALL EXHIBIT THE HIEST QPF UP TO ARND
0.20 INCH OVER THE SE CWA...WHERE GFS SHOWS AN AXIS OF SHARPER H85-7
FGEN AND THE ALL MODELS INDICATE DEEPER MSTR/OMEGA EXTENDING THRU
THE DGZ. SO OPTED TO RETAIN GOING LIKELY POPS IN THIS AREA. PTYPE WL
BE A SGNFT CONCERN. SUSPECT ONLY -FZDZ/FLURRIES WL BE ARND EARLY
WITH RELATIVELY SHALLOW MSTR YET...BUT EITHER RA...SN...OR A MIX IS
MORE LIKELY BY THE AFTN AT LEAST OVER OVER THE SE HALF WITH DEEPER
MSTR/LARGER PCPN PARTICLES. FOR THE PAST SEVERAL RUNS...THE NAM HAS
BEEN WARMEST WITH LLVL TEMPS AND THUS INDICATES RA WL BE THE
PRECOMINANT PTYPE AT LEAST OVER THE SE. THE 12Z CNDN MODEL SUPPORTS
THIS WARMER RUN AS WELL. ATHOUGH THE UNSEASONABLE WARMTH TDAY WOULD
SUG THESE MODELS ARE ON THE RIGHT TRACK...RELATIVELY DRY NATURE OF
THE AIRMASS/POTENTIAL FOR EVAP COOLING HINTS THE COOLER GFS/WRF-ARW/
09Z SREF ARE ON THE RIGHT TRACK. BLENDED IN THAT DIRECTION FOR LLVL
TEMPS FIELDS FOR NOW TO DETERMINE PTYES.
.LONG TERM /00Z TUESDAY THROUGH NEXT SUNDAY/...
MAIN FOCUS FOR THE EXTENDED IS WITH PTYPES AND CHANCES FOR FREEZING
PRECIP FROM MON NIGHT THROUGH WED MORNING...THEN WITH A SYSTEM
MOVING THROUGH WED NIGHT/THU.
A SFC TROUGH/FRONT WILL BE STALLED OVER UPPER MI FROM THE CENTRAL
PLAINS FROM THE START OF THE PERIOD MON NIGHT...THROUGH TUE. A WEAK
UPPER WAVE WILL BE MOVING THROUGH THE ERN CWA PRIOR TO 06Z
TUE...PRODUCING SOME RAIN EAST. THE HARDEST PART OF THIS FORECAST
PERIOD IS THAT SHALLOW MOISTURE WILL EXIST ALONG AND SOUTH OF THE
FRONT...WITH DRY MID LEVELS KEEPING ICE CRYSTALS FROM FORMING. THE
TEMP PROFILE WILL BE SUB-FREEZING THROUGH WEDNESDAY MORNING /EXCEPT
NEAR SFC TEMPS DURING THE DAY TUE/...WHICH WILL KEEP PRECIP WITH THE
DEEPER MOISTURE AND LIFT OVER THE EAST MON NIGHT AS SNOW...AND
DRIZZLE/FREEZING DRIZZLE DIFFERENTIATION ELSEWHERE WILL BE DEPENDENT
ON SFC TEMPS. AT THIS POINT...IT LOOKS LIKE THERE IS POTENTIAL FOR
UP TO A TENTH OF AN INCH OF ICE ACCUMULATION FROM 00Z TUE INTO TUE
MORNING...MAINLY OVER THE WEST HALF OF UPPER MI. SOME UNCERTAINTY
STILL EXISTS WITH HOW MUCH FREEZING DRIZZLE WILL FALL...AND WHERE
THE HEAVIEST AMOUNTS WILL BE.
ATTENTION THEN TURNS TO THE NEXT SYSTEM MOVING IN AS AN UPPER TROUGH
FROM CENTRAL CANADA EXTENDS OVER THE PLAINS AT 00Z THU...MOVES
ACROSS UPPER MI THU...THEN INTO QUEBEC FRI NIGHT. MODELS SEEM TO BE
COMING INTO BETTER AGREEMENT WITH THIS SYSTEM BUT THERE ARE STILL
SOME BIG DIFFERENCES BETWEEN THEM...AND THOSE DIFFERENCES PLAY A
HUGE ROLE IN THE FORECAST. THE GEM AND NAM LOOK ANOMALOUS WITH THE
SYSTEM...SO THEY WERE NOT USED. THE 11/00Z ECMWF...WHICH HAS SHOWN
BETTER RUN TO RUN CONTINUITY THAN THE GFS...HAS A DEEPER UPPER WAVE
CO-LOCATED WITH THE CLOSED SFC LOW THAN THE GFS. THE MAIN DIFFERENCE
BETWEEN THE MODEL STEMS FROM THE STRENGTH OF THE UPPER TROUGH MOVING
IN...WHICH LEADS TO /AMONG OTHER THINGS/ TIMING DIFFERENCES IN THE
LOW LEVELS. THE 11/12Z GFS BRINGS THE SFC LOW INTO THE CWA AROUND
06Z THU...WHILE THE 11/00Z ECMWF LAGS UNTIL AROUND 15Z THU. BOTH
MODELS BRING IN MID LEVEL TEMPS THAT WOULD LEAD TO LIQUID PRECIP
UNTIL THE LOW PASSES AND COLDER AIR COMES IN. SFC TEMPS WED NIGHT
WILL FALL TO AROUND 30F OVER THE WEST HALF OF UPPER MI...BUT SHOULD
STAY NEAR OR ABOVE FREEZING OVER THE EAST HALF. TEMPS OVER THE W
LOOK TO STAY NEAR OR ABOVE FREEZING THROUGH AROUND 03Z THU...AND
STAY THERE UNTIL MID TO LATE MORNING THU. THE GFS BRING THE BULK OF
THE SYNOPTIC QPF /EASILY GREATER THAN 0.25 INCHES IN SOME SPOTS FROM
BOTH THE ECMWF AND GFS/ BETWEEN 00Z AND 12Z THU...WHILE THE ECMWF IS
BETWEEN 12Z AND 18Z THU...SO REGARDLESS OF MODEL THERE IS POTENTIAL
FOR SIGNIFICANT FREEZING RAIN IF ALL THE INGREDIENTS COME TOGETHER.
IT NEEDS TO BE STRESSED AGAIN THAT THERE IS STILL A CONSIDERABLE
AMOUNT OF UNCERTAINTY WITH THIS SYSTEM...ESPECIALLY WITH THE SMALL
SCALE DETAILS NEEDED FOR FREEZING RAIN. DUE TO THE POTENTIAL FOR
SIGNIFICANT FREEZING RAIN ACCUMULATIONS...PAY EXTRA ATTENTION AND
KEEP UP TO DATE WITH LATER FORECASTS ON THIS SYSTEM.
MODELS ARE IN DECENT GENERAL AGREEMENT FROM FRI THROUGH SUN. NW
WINDS AND 850MB TEMPS FALLING TO AOB -12C BY AT LEAST 12Z FRI WILL
MAKE FOR POTENTIAL FOR LES...BUT DRY AIR IS ALSO MOVING IN. A SFC
RIDGE WILL MOVE THROUGH SAT AFTERNOON AND EAST BY LATE
SAT...BRINGING SWLY WINDS. SW FLOW BEHIND THE DEPARTING HIGH E AND
LOW PRESSURE W...ALONG WITH AN UPPER RIDGE BUILDING IN FROM THE
W...WILL LEAD TO 850MB TEMPS INCREASING TO AOA 0C BY LATE SUNDAY.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
EXPECT LLWS TO IMPACT ALL 3 SITES FOR AT LEAST A TIME INTO TONIGHT
WITH STRONG WSW WINDS OVER DECOUPLED PUDDLES OF LINGERING NEAR SFC
COLD AIR. THE LLWS WILL PERSIST LONGEST AT SAW BECAUSE THE WEAKENING
PRES GRADIENT IN ADVANCE OF AN APRCHG LO PRES TROF WILL ARRIVE FM
THE NW AND REACH THAT LOCATION LAST. OTRW...PLAN ON VFR CONDITIONS
THRU THIS EVNG TO GIVE WAY TO IFR/MVFR CONDITIONS LATER TNGT AS AREA
OF GREATER MSTR MOVES IN FM THE SW. SOME -FZDZ WL BE POSSIBLE AT ALL
3 TAF SITES ON MON MRNG WITH SLOWLY DEEPENING MOIST LYR.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT SW WINDS UP TO 30 KTS LATE THIS AFTN TO DIMINISH TONIGHT WITH
THE APPROACH OF A LO PRES TROF AND WEAKER PRES GRADIENT. ALTHOUGH
THERE WILL BE A WSHFT TO THE N FOLLOWING THE PASSAGE OF THIS TROF ON
MON...RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO WED BUT
SLOWLY VEER TO THE S AS A LO PRES SYSTEM DEVELOPING IN THE PLAINS
BEGINS TO MOVE NE TOWARD THE UPPER GREAT LKS. SE WINDS AHEAD OF THIS
LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF. THE MAIN
HAZARD WILL BE AFTER THE LO MOVES TO THE NE ON THU...WHEN NW GALES
IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING WILL
PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE SLOW
APPROACH OF HI PRES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1225 AM EST SUN DEC 11 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PROGRESSIVE WRN
RDG/ERN TROF PATTERN OVER NAMERICA. 12Z H85 TEMPS RANGE FM -18C AT
APX TO 7C AT GLASGOW MT. STRONG SFC-H85 SW FLOW OVER THE NRN PLAINS/
UPR MS RIVER VALLEY BTWN HI PRES IN THE OH VALLEY AND LO PRES NEAR
LK WINNIPEG IS CAUSING WAD AND ALLOWING THE UPR RDG TO BUILD TO THE
E PER 00Z-12Z 100-200M H3 HGT RISES OBSVD TO THE E OF THE UPR RDG
AXIS. THE BACKING LLVL FLOW TO SW OVER THE CWA HAS PUSHED THE SHSN
THAT WERE IMPACTING THE KEWEENAW AND AREAS E OF MUNISING OUT INTO
THE OPEN LK. THE STRONG WAD HAS ALSO CAUSED AN EXPANSIVE AREA OF MID
CLD STRETCHING FM LK WINNIPEG INTO THE UPR GRT LKS/UPR MS VALLEY
WELL APPROXIMATED BY THE HIER RH DEPICTED FM H8-6 ON THE 12Z INL
RAOB AND ON THE NAM 285K ISENTROPIC SFC. HOWEVER...DRY NATURE OF THE
LLVLS PER LARGE SFC-H85 DWPT DEPRESSIONS AND UPSTREAM 12Z RAOBS AS
WELL AS LACK OF ANY OTHER FORCING MECHANISM UNDER THE UPR HGT RISES
IS PREVENTING ANY PCPN EXCEPT OVER FAR NE MN. FARTHER TO THE W...THE
ADVECTION OF MUCH WARMER AND DRIER AIR SHOWN ON THE 12Z BISMARCK
RAOB IS PUSHING THE WRN EDGE OF THE MID CLD STEADILY TO THE E THRU
MN.
&&
.SHORT TERM DISCUSSION /TNGT AND SUN/...
MAIN FCST CONCERNS DURING THIS RELATIVELY QUIET PERIOD WL BE TEMPS
IN WAD PATTERN THAT WL DOMINATE.
TNGT...STRONG WARM/DRY ADVECTION WITH WSW H925-85 FLOW WL DISSIPATE
LINGERING LO/MID CLD SW-NE AS MODELS SHOW STEADILY RISING H85 TEMPS
AND LOWERING RH...INDICATING THE WAD IS BEING MANIFEST AS HORIZONTAL
ADVECTION/EROSION OF COLD AIR AND NOT UPWARD MOTION OVER THE COLD
DOME. IN FACT...NAM/GFS SHOW H85 TEMPS REACHING 7C AT IWD BY 12Z.
ANY PCPN WL BE OVER THE NE HALF OF LK SUP MAINLY THIS EVNG... AND
THIS WL DIMINISH WITH TIME. ALTHOUGH THE DEEPER COLD AIR WL BE
RETREATING...SUSPECT POCKETS OF NEAR SFC COLD AIR WL BE MORE
RESILIENT OVER THE INTERIOR. SO TENDED TOWARD THE LO END OF GUIDANCE
IN THESE AREAS. THE WARMEST LOCATIONS ARE LIKELY TO BE IN THE
DOWNSLOPE AREAS NEAR LK SUP.
SUN...THE CWA WL BE DOMINATED BY THE WARM...DRY WSW FLOW BTWN HI
PRES SINKING INTO THE OH VALLEY AND LO PRES CROSSING NW ONTARIO.
LOOKING UPSTREAM...SKIES ARE MOSUNNY AS THE DRY AIRMASS SHOWN ON THE
12Z BISMARCK RAOB IS DOMINATING. WITH H85 TEMPS FCST TO BE ABOUT
7C...EXPECT TEMPS TO RECOVER WELL ABV NORMAL. HOWEVER...EXACTLY HOW
HI TEMPS CAN RISE WL BE TRICKY WITH RESIDUAL ARCTIC AIR LIKELY TO BE
LINGERING NEAR THE SFC. CONSIDERING THE HI STABILITY SHOWN ON FCST
SDNGS AS WELL AS LO SUN ANGLE...TENDED TOWARD THE LOWER END OF
GUIDANCE. ONCE AGAIN...EXPECT THE HIEST TEMPS ARND 40 IN THE
DOWNSLOPE AREAS NEAR LK SUP WHERE ANY LINGERING NEAR SFC COLD AIR IS
MOST LIKELY TO BE ERODED.
.LONG TERM /00Z MONDAY THROUGH NEXT SATURDAY/...
A WEAK SFC TROUGH WILL EXTEND FROM THE CENTRAL PLAINS STATES THROUGH
PART OF THE CWA FROM LATE SUNDAY THROUGH TUESDAY. MODELS ARE IN
PRETTY GOOD AGREEMENT WITH THIS AND BRINGING AN UPPER SHORTWAVE OVER
THE CWA MONDAY. THE SHORTWAVE COMBINED WITH ISENTROPIC ASCENT WILL
BRING PERIODS OF PRECIP TO THE CWA EARLY MONDAY THROUGH
TUESDAY...WITH THE PRECIP TYPE BEING COMPLEX. THERMAL AND MOISTURE
PROFILES WILL BE THE COMPLICATING FACTOR...AND WILL LEAD TO CHANCES
FOR FREEZING DRIZZLE BEFORE SFC TEMPS WARM UP ON MONDAY...BECOMING
CHANCES FOR A RAIN AND SNOW MIX THROUGH TUESDAY THAT WILL BE MORE
DOMINATED BY SNOW OVER TIME AS COLDER AIR MOVES IN FROM N TO S. MID
LEVEL MOISTURE WILL BE SOMEWHAT LACKING...ESPECIALLY OVER THE SRN
CWA...WHICH FURTHER LOWERS CONFIDENCE ON PTYPE SINCE MOISTURE WILL
BE MINIMAL IN...ABOVE...AND BELOW THE DGZ.
OVERALL CONFIDENCE DECREASES STARTING WEDNESDAY AS MODELS WAIVER
WITH THE HANDLING OF THE NEXT SYSTEM. THE GEM AND ECMWF HAVE BETTER
RUN TO RUN CONTINUITY THAT THE GFS DURING THIS TIME PERIOD...BUT ARE
STILL NOT THAT GREAT. USED A MODEL BLEND FROM WEDNESDAY OUT AS
CONFIDENCE IN ANY MODEL OR SET OF MODELS IS JUST TOO LOW.
LARGE SCALE PATTERN WISE...MODELS SEEM TO HAVE THE SAME GENERAL
IDEA. A 500MB LOW WILL MOVE FROM THE ARCTIC CIRCLE FROM WEDNESDAY TO
HUDSON BAY THURSDAY AS A SERIES OF UPPER LEVEL DISTURBANCES MOVE
INTO THE NWRN CONUS FROM THE NRN PACIFIC. THIS WILL KICK A DEEP
500MB LOW ALREADY IN PLACE OVER SRN CA INTO THE PLAINS WEDNESDAY
NIGHT. THE UPPER LOW WILL WEAKEN TO A WEAK TROUGH AND MOVE UP THE E
SIDE OF A NEW DEEP TROUGH OVER THE W CENTRAL CONUS...WITH THE
SHORTWAVE MOVING OVER THE CWA DURING THE LATTER HALF OF THURSDAY.
MODELS IN THE PAST WERE SHOWING THE UPPER SYSTEM MOVING OVER AS A
DEEPER CLOSED LOW...BUT HAVE BEEN TRENDING WEAKER AND IN MORE OF AN
OPEN WAVE ALOFT.
THIS WHOLE PATTERN WOULD RESULT IN MIXED PRECIP MOVING INTO THE CWA
ON WEDNESDAY AS A WEAK SHORTWAVE MOVE OVER WITH ISENTROPIC ASCENT
ALSO HELPING OUT. THEN AS THE UPPER TROUGH TROUGH MOVES THROUGH
THURSDAY...A CLOSED SFC LOW WILL DEVELOP AND MOVE OVER OR NEAR THE
CWA. THE ECMWF AND GEM BRING THE SFC LOW RIGHT ALONG THE SERN EDGE
OF THE CWA...WHILE THE GFS MOVES IT OVER FARTHER SE OVER CENTRAL
LOWER MI. GIVEN A MODEL BLEND...THE BEST CHANCES FOR PRECIP WILL BE
OVER THE SERN CWA...WHICH IS ALSO WHERE THE CONFIDENCE IN THE
FORECAST WITH THIS SYSTEM IS HIGHEST. PTYPE IS MORE IN
QUESTION...BUT WOULD LEAN TOWARD A RAIN/SNOW MIX OVER THE SERN CWA
AND MORE SNOW OVER THE NWRN CWA. THERE IS POTENTIAL FOR SIGNIFICANT
SNOWFALL ACCUMULATIONS SOMEWHERE IN THE REGION...BUT THAT IS HIGHLY
DEPENDENT ON THE TRACK OF THE SYSTEM. IF THE SYSTEM MOVES SOMEWHERE
BETWEEN THE TRACKS SHOWN BY THE GFS AND ECMWF...IT WOULD BE A
TYPICAL TRACK FOR HEAVY SNOW ACROSS PORTIONS OF THE CWA...BUT
CONFIDENCE IS WA TOO LOW TO PINPOINT THAT AT THIS TIME.
THE SFC LOW EXITS EAST AND HIGH PRESSURE MOVES IN FROM THE W FRIDAY
AND SATURDAY...AS 850MB TEMPS FALL TO AOB -15C. WITH W-NW
WINDS...LES WOULD APPEAR A LIKELY RESULT...BUT MOISTURE...WIND
DIRECTIONS AND OTHER FINICKY INGREDIENTS WILL HAVE TO BE SORTED AS
TIME GOES ON.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
MAIN CONCERN IS FOR LLWS OVERNIGHT AND POTENTIAL REDEVELOPMENT LATE
THIS AFTERNOON. STRONG WAA CONTINUES OVER THE AREA WITH A STABLE
POOL OF COLD AIR AT THE SFC. WINDS CONTINUE TO SLOWLY INCREASE ABOVE
THE INVERSION...CONTINUING LLWS THAT WILL PERSIST THOUGH THE NIGHT
UNTIL MIXING OUT AFTER DAYBREAK. WEAK ISENTROPIC LIFT COMBINED WITH
A SHALLOW LAYER OF HIGHER RHS PRODUCING LOW MVFR CLOUDINESS OVER
NORTHERN WI THAT CONTINUES TO EXPAND INTO UPPER MICHIGAN EARLY THIS
MORNING. THIS CLOUD COVER SHOULD QUICKLY END AS BOUNDARY LAYER MIXES
OUT. WINDS TO DECOUPLE AGAIN WITH SUNSET TOMORROW EVENING. BUFKIT
INDICATES STRONGER WINDS ALOFT TO BE AT KSAW SO WILL INCLUDE LLWS
THERE.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT INCREASING WSW WINDS TO 30 KTS LATE TONIGHT AND SUN UNDER
SHARPENING PRES GRADIENT BETWEEN HI PRES IN THE OH RIVER VALLEY AND
LO PRES CROSSING ONTARIO. BEST CHANCE FOR MARGINAL GALES TO 35 KTS
WILL BE ON SUN IN THE SWATH OVER THE W BETWEEN ISLE ROYALE AND THE
KEWEENAW...WHERE TERRAIN FUNNELING CAN ENHANCE WSW WIND SPEEDS. BUT
GIVEN HI STABILITY...OPTED TO MAINTAIN JUST MENTION OF GALE FORCE
GUSTS ATTM. WITH A LO PRES TROF/WEAKER GRADIENT SINKING ACROSS LK
SUP ON MON/MON NIGHT...LOOK FOR WINDS TO DIMINISH AND SHIFT TO THE
N. LIGHT WINDS SHIFTING TO THE S WILL THEN BE THE RULE INTO WED AS A
HI PRES RIDGE SLIDES OVER THE LK AND TO THE E. ANOTHER LO PRES WILL
MOVE NE TOWARD THE UPPER LKS ON THU...BUT GALES DO NOT APPEAR LIKELY
ATTM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
806 AM CST SUN DEC 11 2011
.UPDATE...
UPDATED SKY GRIDS/SAF/ZFP FOR TODAY TO ACCOUNT FOR STRATUS MOVING
NORTHEAST NEAR 25 KNOTS ACROSS EASTERN NEBRASKA AND WESTERN IA.
THIS PLACES THE LEADING EDGE INTO THE TWIN CITIES AROUND 18Z. ALSO
ADDED FOG TO SOUTH CENTRAL MN AS NEAR 30 DEGREE DEW POINTS PUSH ACROSS
THE SNOW COVER. RUC 950MB RH HAS A GREAT HANDLE ON THE SITUATION.
IT WOULD SUGGEST THE CLOUDS PUSHING ALL THE WAY TO NORTHERN WI BY
LATE AFTERNOON.
&&
.DISCUSSION... /ISSUED 412 AM CST SUN DEC 11 2011/
SUMMARY...WILL KEEP THIS DISCUSSION SOMEWHAT SHORT AND SWEET AS
THERE HASN`T BEEN MUCH CHANGE IN THE SHORT TERM FORECAST AND
PREVIOUS DISCUSSIONS HAVE ALREADY ARTICULATED THE FREEZING DRIZZLE
THREAT SUNDAY NIGHT AND MONDAY MORNING. THERE ARE NOTABLE CHANGES
IN THE EXTENDED WITH RESPECT TO HOW THE GFS IS NOW HANDLING THE
WEDNESDAY/THURSDAY SYSTEM.
FIRST OFF...HAVE WARMED TEMPS TODAY. WE`RE STARTING OFF QUITE WARM
AND WILL STILL BE WARM ADVECTING TODAY. WENT WITH TEMPS AROUND 50
OUT BY BUFFALO RIDGE WHERE LOCATIONS ARE STILL IN THE UPPER 30S AT
THIS HOUR WITH DOWNSLOPING IN FULL EFFECT. ACTUALLY HOPE THAT WE
WENT WARM ENOUGH IN SNOW FREE AREAS OF WESTERN MN. THERMAL
PROFILE...SUNSHINE...AND A FAVORABLE SOUTHWEST MIXING WIND WOULD
SUGGEST LOWER TO MID 40S ARE WELL WITHIN REACH FOR MANY LOCATIONS.
LOOKS LIKE WE`LL PROBABLY MIX TO AROUND 950MB AND THIS WOULD YIELD
PLENTY OF UPPER 30S AND LOWER 40S OFF THE GFS...A FEW DEGREES
WARMER OFF THE NAM. MIXING TO 925MB WOULD PROVIDE READINGS IN THE
MID 40S...EVEN IN SOME OF OUR SNOW COVERED AREAS.
DRIZZLE EVENT STILL ON TRACK LATE TONIGHT AND MONDAY MORNING.
SURROUNDING OFFICES DISCUSSED THE POTENTIAL FOR A FREEZING RAIN
ADVISORY AND WILL DEFER TO THE DAY SHIFT...SEEMS LIKE A GOOD BET
THOUGH. THE BIGGER QUESTIONS ARE NOT SO MUCH WILL IT
DRIZZLE...BUT HOW MUCH AND HOW LONG DOES IT STAY FREEZING DRIZZLE.
I LIKE THE CHANGES MADE IN YESTERDAYS AFTERNOON FORECAST. PTYPE
SHOULD ALMOST EXCLUSIVELY BE DRIZZLE/FREEZING DRIZZLE. DON`T SEE A
LOT OF OMEGA THAT WOULD INDICATE BIGGER DROP SIZE AND RAIN...AND
WE CERTAINLY DON`T APPEAR TO HAVE THE RH ALOFT FOR SNOW. HOPEFULLY
THE DAY SHIFT CAN BETTER DEFINE THE WESTERN EXTENT OF THE DRIZZLE
AND ALSO HOW MUCH ICE ACCUMULATION WE`LL MANAGE WHEN TEMPS ARE BELOW
FREEZING.
WE`LL LIKELY END UP WITH 4 DAYS IN A ROW OF HIGHS CLIMBING ABOVE
FREEZING...BEGINNING TODAY...AND FINALLY COMING TO AN END AFTER
THE SYSTEM THAT PASSES THROUGH MID WEEK. STILL SOME ISSUES TO BE
WORKED OUT WITH THIS SYSTEM...BUT ALL SIGNS UP TO THIS POINT
SUGGEST A MESSY FORECAST WITH MULTIPLE PRECIP TYPES. OF THE LATEST
00Z/06Z GUIDANCE...NAM IS THE FASTEST WITH THIS SYSTEM...FOLLOWED
BY THE GFS...AND THEN THE ECMWF. INTERESTING HOW THE GFS HAS
REVERTED BACK TO A SOLUTION QUITE SIMILAR TO IT`S OLD RUN AT
09.18Z AFTER YESTERDAY`S SOLUTIONS THAT WERE MUCH FURTHER SOUTH.
THERE`S AT LEAST MORE CONFIDENCE IN A WARM SOLUTION WHERE LIQUID
DROPS AND NOT ICE CRYSTALS WILL BE IN CONTROL UNTIL WEDNESDAY
NIGHT. THE HALF INCH OR SO OF QPF BEING SPIT OUT OF THE MODELS
SHOULD MOSTLY FALL AS RAIN. THE CONCERN IS THE FORECAST SOUNDINGS
SUGGEST A PERIOD OF FREEZING RAIN WEDNESDAY MORNING WITH THE MAIN
BATCH OF ISENTROPIC LIFT...BEFORE EVENTUALLY SWITCHING OVER TO
RAIN WHEN TEMPS WARM DURING THE AFTERNOON. CERTAINLY A SYSTEM
WE`RE WATCHING CLOSELY AND SOMETHING WE`LL CONTINUE TO REFINE OVER
THE NEXT FEW DAYS.
&&
.AVIATION... /12Z TAF ISSUANCE/
SEVERAL ISSUES AT HAND WITH THIS TAF SET - INITIAL LLWS...LOW
CLOUDS COMING IN TONIGHT...TIMING OF POTENTIALLY FROZEN PRECIP MON
MORNING. AS FOR LLWS...ASCENDING 12Z KMPX RAOB SHOWED 1 KFT WINDS
AS 240/43KT. MODEL GUIDANCE SHOWED SPEEDS EVEN A FEW KTS HIGHER.
WITH SFC WINDS ARND 20008KT...THIS MEETS THE THRESHOLDS FOR LLWS
SO HAVE INCLUDED IT FOR THE FIRST 4-6 HRS OF EACH TAF. IF MIXING
IS STRONGER/DEEPER THAN ANTICIPATED THEN LLWS MAY END EARLIER BUT
THAT WOULD MEAN SFC WINDS WOULD INCREASE EARLIER/STRONGER THAN
EXPECTED. NEXT ISSUE IS LOW CLOUDS LATE TONIGHT AHEAD OF A SLOW
MOVING CDFNT. ENHANCED MOISTURE TRANSPORT AHEAD OF THE FRONT WILL
BRING A MUCH DEEPER MOISTURE PROFILE TO THE REGION WHICH
TRANSLATES TO MUCH LOWER CLOUD DECKS DEVELOPING LATE TONIGHT
THROUGH MONDAY MORNING...INCLUDING DOWN TO IFR LEVELS. TIMING OF
THE LOW CLOUDS IS A LITTLE TRICKY...BUT HAVE STAYED CLOSE TO
BUFKIT PROFILES FROM BOTH THE NAM AND GFS WHICH LOOKED TO HAVE THE
LOW CLOUDS IN PLACE AFTER 06Z TONIGHT. LAST MAIN ISSUE IS THE
POTENTIAL FOR FROZEN PRECIPITATION FOR MAINLY KMSP-KRNH-KEAU. BEST
DYNAMICS AND MOISTURE LOOK BEST FOR SRN MN INTO WRN WI...SO THIS
SHOULD SPARE KAXN-KSTC-KRWF FROM ANY PRECIP. HOWEVER...THE
ORIENTATION OF THE INCOMING SLOW-MOVING FROM /SW TO NE/ ALONG WITH
THE ADDITIONAL MOISTURE SHOULD BE ENOUGH TO SQUEEZE OUT A FEW
HUNDREDTHS OF LIQUID ACCUMULATION. GIVEN A SHALLOW ENOUGH LOW
LEVEL FREEZING LAYER BUT ONE DROPPING NO LOWER THAN -5 DEG C...A
PERIOD OF -FZDZ LOOKS INCREASINGLY LIKELY FOR AROUND DAYBREAK
MONDAY THROUGH LATE MORNING. HAVE INCLUDED A PROB30 TO ACCOUNT
THAT IT MAY START EARLIER THAN 12Z. THERE IS ALSO THE POSSIBILITY
THAT THE INCREASE IN DEWPOINTS MAY NUDGE UP THE AIR TEMPERATURE
ENOUGH TO BRING SFC TEMPS ABOVE FREEZING... KEEPING PRECIP AS ALL
LIQUID AND SHRINKING THE DURATION OF -FZDZ. CERTAINLY A LOT TO
KEEP AN EYE ON AS THIS EVENT UNFOLDS.
MSP...SOME HZ ARND THE FIELD AS WARMER DEWPOINTS MOVE ACROSS
GROUNDS THAT HAD SEEN THE TEMPERATURE REMAIN BELOW 20 DEG F FOR
A FEW DAYS. THE BR/HZ WILL BURN OFF SHORTLY AFTER SUNRISE...
MAKING FOR A BREEZY AND MOSTLY SUNNY DAY. CLOUDS INCREASE TONIGHT
AHEAD OF A SLOW-MOVING CDFNT DUE TO PASS ACROSS THE REGION MONDAY.
WILL SEE CIGS FORM OVERNIGHT...LIKELY INTO THE IFR CATEGORY. THIS
WILL BE FOLLOWED BY THE POTENTIAL FOR -FZDZ MAINLY BETWEEN 12Z-18Z
BUT POSSIBLY AS EARLY AS 08Z-12Z. MODEL TIMING HIGHLIGHTS AFTER
12Z...BUT THERE ARE ALSO INDICATIONS THAT THE DURATION COULD BE
CUT SHORT DUE TO STRONGER WARM AIR ADVECTION THAN CURRENTLY
FORECAST WHICH COULD CHANGE THE PRECIP TO ALL LIQUID QUICKER THAN
CURRENTLY FORECAST. IN ADDITION...THE AMOUNT OF PRECIP WILL NOT BE
MUCH. ONLY AROUND A TENTH OF AN INCH OF LIQUID ACCUMULATION IS
EXPECTED. SO...ALTHOUGH THIS IS A HIGH POP/LOW QPF EVENT...THERE
MAY BE JUST ENOUGH ICE TO CAUSE PROBLEMS MONDAY MORNING.
OUTLOOK...MVFR/IFR CIGS MON NIGHT WITH POSSIBLE -FZDZ IN THE
EVENING. VFR TUE WITH MIDLVL DECKS AS HIGH PRESSURE MOVES ACROSS.
WELL-ORGANIZED STORM SYSTEM EXPECTED TO IMPACT THE REGION WED INTO
THU WITH A VARIETY OF PRECIPITATION TYPES POSSIBLE...WITH FLIGHT
CATEGORY RESTRICTIONS /MAINLY DUE TO CIGS/ DOWN TO IFR LIKELY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/CLF/JPC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1134 AM CST Sun Dec 11 2011
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Range (Sunday through Tuesday)...
After today, an unsettled weather pattern will start of the work
week with rain chances increasing markedly by Tuesday.
An extensive filed of stratus and fog that stretched from the TX
Panhandle into central KS yesterday has spread into the western 1/3
of the CWA overnight. Short range models HRRR and RUC indicate the
stratus will likely linger through the morning hours across northern
and parts of west central MO before clearing from the ssw. Numerous
breaks in the low clouds over northern KS complicates the forecast.
However, the short range models suggest these holes will cloud back
up. Should this occur the northwestern counties would be the last to
clear. Have lowered high temperatures across the northwest 1/2 of
the CWA due to the lingering low clouds.
Increasing mid level warm air advection will generate the next wave
of clouds that will spread northeast across TX/OK and into the
western CWA tonight. A weak but persistent h7 shortwave with
attendant isentropic lift is expected to generate patchy very light
rain tonight across the nw 1/2 of the CWA. Since the rain will be
quite light and may not even measure can only justify 15-25% pops.
Mid/upper level winds will back to the southwest for Monday/Tuesday
with extensive warm air advection mid and high level cloudiness
affecting the region. Monday and the first part of Monday night
should be dry due to marginal isentropic lift and no discernible
waves moving through the flow. That will all change later Monday
night through Tuesday as deep isentropic lift at multiple levels and
periodic shortwaves lifting northeast through the region will likely
result in periods of showers. The model trends have been showing
increasing pops and pattern recognition supports this. Can envision
later forecasts further raising pops on Tuesday. The diurnal
temperature range on Tuesday will be limited due to the cloud cover
and expected rain, so favor lowering max temperatures a bit while
raising the overnight lows for Monday and Tuesday nights.
MJ
Medium Range (Wednesday through Saturday)...
The main feature of interest in the medium range continues to be the
well advertised upper level trough that will develop tonight over
the southwestern CONUS. As has been the case over several runs of
the ECMWF and the GFS, the GFS continues to be faster and further
south with this system. However, the model spread has come closer
together over the past couple of runs.
By Wednesday, the upper level trough will move out into the Southern
Rockies as a surface low pressure develops out across eastern
Colorado/western Kansas. This surface low will track through the
Central Plains during the day Wednesday and into the Upper Midwest
Wednesday night forcing a cold front through the forecast area. Out
ahead of the front, good WAA, frontogenetical forcing, and elevated
instability will allow for copious rain with PWATs between
1.0"-1.25" and even a few thunderstorms possible. Temperatures out
ahead of the front on Wednesday will be well above average with
highs ranging from near 50 across northwestern Missouri to around 60
across southern portions of the forecast area.
Showers may linger across eastern portions of the forecast area into
Thursday morning as the upper level trough moves through the
forecast area. Otherwise, the rest of the medium range looks dry as
a surface ridge of high pressure builds in behind the departing
system on Thursday and will remain in control over the region
through the remainder of the period. Temperatures on Thursday will
range from the upper 30s to the lower 40s across the CWA with
seasonably cool temperatures expected for Friday and Saturday with
highs ranging from the mid 30s to low 40s.
73
&&
.AVIATION...
Temporary break in the cloud cover currently being experienced across
the terminals late this morning. Secondary, mainly VFR cloud deck,
will overspread the terminals within the next couple of hours.
Otherwise, seeing winds becoming gusty across portions of Kansas and
have added mention of gusts within the cloud break period. Attention
then turns to late tonight and into early tomorrow morning as
uncertainty again exists with respect to low clouds and fog
potential. Will hold off on any mention at the current time as deeper
mixing may help offset extent of nocturnal cooling and low cloud
development. However as seen yesterday, later shifts may have to add
mention should signals appear stronger.
DEROCHE
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
542 AM CST SUN DEC 11 2011
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Range (Sunday through Tuesday)...
After today, an unsettled weather pattern will start of the work
week with rain chances increasing markedly by Tuesday.
An extensive filed of stratus and fog that stretched from the TX
Panhandle into central KS yesterday has spread into the western 1/3
of the CWA overnight. Short range models HRRR and RUC indicate the
stratus will likely linger through the morning hours across northern
and parts of west central MO before clearing from the ssw. Numerous
breaks in the low clouds over northern KS complicates the forecast.
However, the short range models suggest these holes will cloud back
up. Should this occur the northwestern counties would be the last to
clear. Have lowered high temperatures across the northwest 1/2 of
the CWA due to the lingering low clouds.
Increasing mid level warm air advection will generate the next wave
of clouds that will spread northeast across TX/OK and into the
western CWA tonight. A weak but persistent h7 shortwave with
attendant isentropic lift is expected to generate patchy very light
rain tonight across the nw 1/2 of the CWA. Since the rain will be
quite light and may not even measure can only justify 15-25% pops.
Mid/upper level winds will back to the southwest for Monday/Tuesday
with extensive warm air advection mid and high level cloudiness
affecting the region. Monday and the first part of Monday night
should be dry due to marginal isentropic lift and no discernible
waves moving through the flow. That will all change later Monday
night through Tuesday as deep isentropic lift at multiple levels and
periodic shortwaves lifting northeast through the region will likely
result in periods of showers. The model trends have been showing
increasing pops and pattern recognition supports this. Can envision
later forecasts further raising pops on Tuesday. The diurnal
temperature range on Tuesday will be limited due to the cloud cover
and expected rain, so favor lowering max temperatures a bit while
raising the overnight lows for Monday and Tuesday nights.
MJ
Medium Range (Wednesday through Saturday)...
The main feature of interest in the medium range continues to be the
well advertised upper level trough that will develop tonight over
the southwestern CONUS. As has been the case over several runs of
the ECMWF and the GFS, the GFS continues to be faster and further
south with this system. However, the model spread has come closer
together over the past couple of runs.
By Wednesday, the upper level trough will move out into the Southern
Rockies as a surface low pressure develops out across eastern
Colorado/western Kansas. This surface low will track through the
Central Plains during the day Wednesday and into the Upper Midwest
Wednesday night forcing a cold front through the forecast area. Out
ahead of the front, good WAA, frontogenetical forcing, and elevated
instability will allow for copious rain with PWATs between
1.0"-1.25" and even a few thunderstorms possible. Temperatures out
ahead of the front on Wednesday will be well above average with
highs ranging from near 50 across northwestern Missouri to around 60
across southern portions of the forecast area.
Showers may linger across eastern portions of the forecast area into
Thursday morning as the upper level trough moves through the
forecast area. Otherwise, the rest of the medium range looks dry as
a surface ridge of high pressure builds in behind the departing
system on Thursday and will remain in control over the region
through the remainder of the period. Temperatures on Thursday will
range from the upper 30s to the lower 40s across the CWA with
seasonably cool temperatures expected for Friday and Saturday with
highs ranging from the mid 30s to low 40s.
73
&&
.AVIATION...
For the 12Z TAFs, increasing low level moisture has resulted in a
shallow VLIFR cloud deck with MVFR fog which has spread across all 3
terminals. While AvnFPS climatology supports holding onto at least
IFR cigs through 18z, satellite imagery indicates an MVFR deck
quickly approaching from the southwest. These clouds should reach
the terminals by late morning and linger until a VFR deck of mid
clouds moves in for tonight.
While the forecast does not specifically mention rain in it,
increasing isentropic ascent with a weak 700mb shortwave trough may
generate very light but scattered showers or sprinkles. This
precipitation is not likely to measure nor cause a reduction in
visibility. So, will leave mention of them out for now, but
something to be aware of in future forecasts.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
419 AM CST SUN DEC 11 2011
.DISCUSSION...
Short Range (Sunday through Tuesday)...
After today, an unsettled weather pattern will start of the work
week with rain chances increasing markedly by Tuesday.
An extensive filed of stratus and fog that stretched from the TX
Panhandle into central KS yesterday has spread into the western 1/3
of the CWA overnight. Short range models HRRR and RUC indicate the
stratus will likely linger through the morning hours across northern
and parts of west central MO before clearing from the ssw. Numerous
breaks in the low clouds over northern KS complicates the forecast.
However, the short range models suggest these holes will cloud back
up. Should this occur the northwestern counties would be the last to
clear. Have lowered high temperatures across the northwest 1/2 of
the CWA due to the lingering low clouds.
Increasing mid level warm air advection will generate the next wave
of clouds that will spread northeast across TX/OK and into the
western CWA tonight. A weak but persistent h7 shortwave with
attendant isentropic lift is expected to generate patchy very light
rain tonight across the nw 1/2 of the CWA. Since the rain will be
quite light and may not even measure can only justify 15-25% pops.
Mid/upper level winds will back to the southwest for Monday/Tuesday
with extensive warm air advection mid and high level cloudiness
affecting the region. Monday and the first part of Monday night
should be dry due to marginal isentropic lift and no discernible
waves moving through the flow. That will all change later Monday
night through Tuesday as deep isentropic lift at multiple levels and
periodic shortwaves lifting northeast through the region will likely
result in periods of showers. The model trends have been showing
increasing pops and pattern recognition supports this. Can envision
later forecasts further raising pops on Tuesday. The diurnal
temperature range on Tuesday will be limited due to the cloud cover
and expected rain, so favor lowering max temperatures a bit while
raising the overnight lows for Monday and Tuesday nights.
MJ
Medium Range (Wednesday through Saturday)...
The main feature of interest in the medium range continues to be the
well advertised upper level trough that will develop tonight over
the southwestern CONUS. As has been the case over several runs of
the ECMWF and the GFS, the GFS continues to be faster and further
south with this system. However, the model spread has come closer
together over the past couple of runs.
By Wednesday, the upper level trough will move out into the Southern
Rockies as a surface low pressure develops out across eastern
Colorado/western Kansas. This surface low will track through the
Central Plains during the day Wednesday and into the Upper Midwest
Wednesday night forcing a cold front through the forecast area. Out
ahead of the front, good WAA, frontogenetical forcing, and elevated
instability will allow for copious rain with PWATs between
1.0"-1.25" and even a few thunderstorms possible. Temperatures out
ahead of the front on Wednesday will be well above average with
highs ranging from near 50 across northwestern Missouri to around 60
across southern portions of the forecast area.
Showers may linger across eastern portions of the forecast area into
Thursday morning as the upper level trough moves through the
forecast area. Otherwise, the rest of the medium range looks dry as
a surface ridge of high pressure builds in behind the departing
system on Thursday and will remain in control over the region
through the remainder of the period. Temperatures on Thursday will
range from the upper 30s to the lower 40s across the CWA with
seasonably cool temperatures expected for Friday and Saturday with
highs ranging from the mid 30s to low 40s.
73
&&
.AVIATION...
For the 00Z tafs, the weak high pressure system has shifted east
with a return to light south southwest flow. Models suggest VFR
conditions through the period as a weak high pressure ridge aloft
builds across the Central Plains. However, there has been a LIFR
stratus deck in eastern Kansas, moving northeast. It appears that
nocturnal cooling along with advection will allow this deck to move
into the terminals aft 07Z. IFR conditions are expected with
possible ceilings as low as 300 feet between 08z to 12z. The cloud
deck is quite thin with several breaks. With increasing mixing in
the morning hours, the cloud deck should quickly erode. However,
confidence in the timing is low.
DB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1019 PM CST Sat Dec 10 2011
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Brisk southwest winds coupled with abundant sunshine have allowed
afternoon temperatures to climb into the mid to upper 30s across
northeast Missouri to the middle 40s across eastern Kansas and
western Missouri. While gusty conditions are expected to subside this
evening, moderate southwesterly sfc flow is expected to persist
overnight as a sfc low slides across the northern tier of the country
while sfc ridging moves into the Ohio valley. Stubborn stratus has
been slow to erode across southwestern Kansas this afternoon with
models doing a poor job resolving the feature. Uncertainty remains
high as to whether additional stratus will develop overnight and
advect northeastward. There appears to be some support of this idea
from the latest RUC and VSREF outputs after 03-04z. Will hold off on
stratus mention at the moment although may have to be added by later
shifts should stratus development show signs of coming to fruition.
Southerly low level flow will be maintained tomorrow as the
aforementioned sfc low skirts across southern Canada. This coupled
with increasing thicknesses should yield temperatures climbing a few
degrees higher than seen today. By Sunday night, 35-40kt LLJ may
support a few showers across far northwest Missouri as isentropic
ascent increases across this area.
Vigorous upper level trough will begin translating across the
southwestern US during the beginning of the week spreading height
falls across the plains. This will maintain WAA regime Monday and
Tuesday keeping afternoon temperatures in the 40s to near 50
degrees. The amount of warming will likely be offset to some extent by
increasing cloud cover during this time frame. Guidance has come into
better agreement on a lead wave ejecting across the plains during the
day Tuesday bringing the first round of rain the region. Have
increase POPs to the high chance category during the day Tuesday with
likely wording for Tuesday night across portions of central Missouri.
The main upper system then moves into the plains and Midwest on
Wednesday keeping high rain chances in place through Wednesday night. In
addition, sufficient moisture and ascent should be in place for at
least an isolated chance of thunderstorms as well. This system slides
east of the area by Thursday with the next upper trough diving into
the desert southwest by Friday. Uncertainty increases thereafter and
have went with a dry forecast through the remainder of the forecast
to account.
DEROCHE
&&
.AVIATION...
For the 00Z tafs, the weak high pressure system has shifted east
with a return to light south southwest flow. Models suggest VFR
conditions through the period as a weak high pressure ridge aloft builds
across the Central Plains. However, there has been a LIFR stratus
deck in eastern Kansas, moving northeast. It appears that nocturnal
cooling along with advection will allow this deck to move into the
terminals aft 07Z. IFR conditions are expected with possible ceilings
as low as 300 feet between 08z to 12z. The cloud deck is quite thin with
several breaks. With increasing mixing in the morning hours, the
cloud deck should quickly erode. However, confidence in the timing is
low.
DB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1245 PM CST SUN DEC 11 2011
.UPDATE...
UPDATED THE FORECAST FOR TEMPERATURES TODAY AS HIGHS WERE
APPROACHING OR HAD SURPASSED FORECAST HIGHS OVER NORTH CENTRAL AND
PORTIONS OF NORTHWEST NEBRASKA. WESTERLY DOWN SLOPE WINDS IN THESE
AREAS AND FULL SUNSHINE SHOULD ALLOW TEMPERATURES TO RISE INTO THE
UPPER 40S TO NEAR 50 IN SOME LOCATIONS BY MID AFTERNOON. ALSO...IN
THE FAR SOUTHEAST AND EASTERN PARTS OF THE FORECAST AREA THERE
IS A PERSISTENT STRATUS DECK WHICH HAS SIGNIFICANTLY SLOWED THE
TEMPERATURE RISE SO FAR TODAY. SOME OF THESE PLACES MAY NOT GET
OVER THE FREEZING POINT AND HAVE ADJUSTED HIGHS ACCORDINGLY.
&&
.PREV DISCUSSION... /ISSUED 1154 AM CST SUN DEC 11 2011/
AVIATION... /FOR THE 18Z TAF ISSUANCE/
AT MID-DAY IFR CONDITIONS MAINLY STAYING ACROSS CENTRAL AND
EASTERN NEBRASKA /JUST EDGING INTO THE FORECAST AREA WHERE
SNOW PACK REMAINS/. THESE CONDITIONS ARE EAST OF KLBF AND KVTN SO
VFR FORECAST WILL CONTINUE INTO TONIGHT FOR THESE LOCATIONS.
A COLD FRONT WILL SLOWLY MAKE ITS WAY EAST ACROSS NEBRASKA TONIGHT
AND MONDAY. WINDS IN THE VICINITY OF THE FRONT WILL BE LIGHT WITH
A SWITCH TO THE NORTHWEST BEHIND THE FRONT. BELIEVE THERE WILL BE
ENOUGH LOW LEVEL MOISTURE TO CAUSE SOME STRATUS AND FOG TO
DEVELOP IN THE MORNING...ESPECIALLY WHERE THERE IS SNOW PACK AS
THESE AREAS WILL SEE SOME MELTING DURING THE DAY TODAY. THIS AREA
IS MAINLY EAST OF THE TAF SITES...BUT THINK THERE WILL BE SOME
MVFR VISIBILITIES AT KLBF OVERNIGHT. THESE SHOULD QUICKLY IMPROVE
IN THE MORNING AS THE FRONT MOVES THROUGH...PUSHING THE MOISTURE
OUT AS THE WESTERLY WINDS INCREASE. LOOKING NORTHWARD...A SURFACE
LOW IS EXPECTED TO BE NEAR THE SD/NE/IA JUNCTURE. THERE IS A
PRETTY CONSISTENT SIGNAL THAT LOW LEVEL MOISTURE WILL BE PULLED
SOUTH INTO NORTHERN NEBRASKA BEHIND THE LOW. EXPECTING TO SEE
LOWERED CEILINGS AND VISIBILITIES IN THE VICINITY OF 12Z AT KVTN
WITH IFR/MVFR CEILINGS CONTINUING INTO THE AFTERNOON.
PREV DISCUSSION... /ISSUED 358 AM CST SUN DEC 11 2011/
DISCUSSION...
A PRETTY INVOLVED FORECAST IS TAKING SHAPE FOR MID WEEK AS MEDIUM
RANGE MODELS ALL INDICATE A TROUGH DIGGING DOWN THE WEST COAST OF
NORTH AMERICA...THEN EJECTING ACROSS THE FOUR CORNERS REGION TOWARD
THE PLAINS. INCONSISTENCY FROM RUN TO RUN IN HOW THE MODELS
EVENTUALLY EJECT THE SYSTEM HAVE CREATED LOW CONFIDENCE AT THIS
POINT IN TIME...ESPECIALLY CONCERNING PRECIPITATION TYPE...AS
RAIN...FREEZING RAIN AND SNOW WOULD ALL BE WITHIN THE REALM OF
POSSIBILITY. BUT BEFORE DIVING INTO THE MID WEEK SYSTEM...THE
FORECAST TODAY MAY BE TRICKY AS WELL. NEAR TERM SOLUTIONS ARE
PICKING UP ON A THIN ENVELOPE OF BL MOISTURE...PROBABLY FROM THE
EXTENSIVE ERODING SNOW PACK THAT RESIDES FROM SOUTHWEST TO
NORTHEAST NEBRASKA...AND TO A GREATER EXTENT...MOISTURE ADVECTION
FROM THE SOUTH. SEVERAL OF THE NEAR/SHORT TERM SOLUTIONS SUCH AS
THE HRRR AND NAM DEVELOP STRATUS TODAY ACROSS OUR SOUTHEASTERN
ZONES...WHICH WOULD LIMIT AFTERNOON HIGHS AOB THE MELTING POINT.
IN FACT...MET GUIDANCE IS SUGGESTING A HIGH OF JUST 30F THIS
AFTERNOON AT LBF...COMPARED TO THE MAV GUIDANCE OF 39F. GENERALLY
SIDED TOWARD THE WARMER GUIDANCE OUTPUT...WITH EXPECTED HIGHS ACROSS
OUR SOUTHEASTERN ZONES IN THE MID TO UPPER 30S. THIS IS BASED OFF
OF RECENT SATELLITE TRENDS OF THE LOWER CEILING BUILDING EAST...AND
THAT THE 00Z NAM INDICATES THAT THE 30-60 AGL MB RH IS NOT
SATURATED. ACROSS FAR NORTHWEST NEBRASKA...DRIER BL RH WILL AID
IN WARMING AFTERNOON T/S IN THE LOW TO MID 40S ONCE AGAIN.
A WEAK BOUNDARY SLIDES THROUGH THE CWA EARLY ON MONDAY COOLING
TEMPERATURES BACK INTO THE 30S CWA WIDE...WITH LOWS MONDAY MORNING
RETURNING INTO THE TEENS AND LOW 20S. BUFR SOUNDINGS CONTINUE TO
INDICATE A THIN ENVELOPE OF MOISTURE NEAR THE SURFACE EARLY MONDAY
MORNING WHICH COULD LEAD TO THE FORMATION OF PATCHY LOW FOG...WILL
CARRY THE MENTION OF -FG GENERALLY SOUTHEAST OF A CHAMBERS TO NORTH
PLATTE LINE...WHERE SLIGHTLY STRONGER MOISTURE TRANSPORT FROM THE
GULF WILL CREATE A DEEPER SATURATED PROFILE.
EARLY TUESDAY MORNING IS WHEN THINGS POTENTIALLY GET INTERESTING.
DEEPER MOISTURE TRANSPORT ON THE 280K THROUGH 290K ISENTROPIC
SURFACES COULD BRING SOME LIGHT QPF INTO CENTRAL...AND SOUTH CENTRAL
NEBRASKA. CROSS SECTIONS...WITH SUPPORT FROM BUFR SOUNDINGS
CONTINUE TO INDICATE THE TOP OF THE SATURATED LAYER SLIGHTLY ABOVE
0C...BUT COOLING RAPIDLY TOWARD THE SURFACE. NOT SEEING INITIALLY
ANY SEEDER FEEDER PROCESSES GOING...SO DRIZZLE OR LIGHT FREEZING
RAIN WOULD BE THE EXPECTED PTYPE EARLY ON TUESDAY. HOWEVER
CONDITIONS WILL DETERIORATE THROUGH THE DAY...AS DEEPER MOISTURE AND
BETTER FORCING ARRIVES WITH THE EJECTING WAVE. THE NAM....GFS AND
EURO ALL NOW INDICATE PROFILES FAVORABLE FOR FREEZING RAIN ACROSS
OUR SOUTHEASTERN ZONE BY 00Z WEDNESDAY. MODELS BEGIN TO DIVERGE
FROM THERE ON...AS THE GFS AND NAM CONTINUE TO BE PROGRESSIVE BY
PHASING WITH THE NORTHERN STREAM...WHEREAS THE EUROPEAN CAMP HAS
REVERTED BACK TO A CLOSED NEGATIVELY TILTED H5 LOW. THE QUICKER
SOLUTIONS WOULD INDICATE THE BULK OF THE PRECIPITATION THAT WOULD
FALL WOULD BE AS FREEZING RAIN...ESPECIALLY FOR LOCATIONS EAST OF A
NORTH PLATTE TO AINSWORTH LINE. HOWEVER...THE SLOWER SOLUTION WOULD
ALLOW FOR MORE COOLER AIR TO BE DRAWN INTO THE SYSTEM...THUS FORCING
A QUICKER CHANGE OVER TO SNOW...WITH POSSIBLY SIGNIFICANT
ACCUMULATIONS. SINCE THERE CONTINUES TO BE INCONSISTENCY WITH RUN
TO RUN SOLUTIONS...AND SIGNIFICANT DIFFERENCES IN THE EVENTUAL
OUTCOME OF THE SYSTEM WHEN IT REACHES THE PLAINS...FELT IT WAS BEST
TO CARRY FORWARD LOW END CHANCE/SLIGHT CHANCE POPS FOR MUCH OF THE
CWA TUESDAY NIGHT THROUGH EARLY THURSDAY...LEAVING THE HIGHEST POPS
TARGETING OUR EASTERN ZONES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 AM CST SUN DEC 11 2011
.AVIATION... /FOR THE 18Z TAF ISSUANCE/
AT MID-DAY IFR CONDITIONS MAINLY STAYING ACROSS CENTRAL AND
EASTERN NEBRASKA /JUST EDGING INTO THE FORECAST AREA WHERE
SNOW PACK REMAINS/. THESE CONDITIONS ARE EAST OF KLBF AND KVTN SO
VFR FORECAST WILL CONTINUE INTO TONIGHT FOR THESE LOCATIONS.
A COLD FRONT WILL SLOWLY MAKE ITS WAY EAST ACROSS NEBRASKA TONIGHT
AND MONDAY. WINDS IN THE VICINITY OF THE FRONT WILL BE LIGHT WITH
A SWITCH TO THE NORTHWEST BEHIND THE FRONT. BELIEVE THERE WILL BE
ENOUGH LOW LEVEL MOISTURE TO CAUSE SOME STRATUS AND FOG TO
DEVELOP IN THE MORNING...ESPECIALLY WHERE THERE IS SNOW PACK AS
THESE AREAS WILL SEE SOME MELTING DURING THE DAY TODAY. THIS AREA
IS MAINLY EAST OF THE TAF SITES...BUT THINK THERE WILL BE SOME
MVFR VISIBILITIES AT KLBF OVERNIGHT. THESE SHOULD QUICKLY IMPROVE
IN THE MORNING AS THE FRONT MOVES THROUGH...PUSHING THE MOISTURE
OUT AS THE WESTERLY WINDS INCREASE. LOOKING NORTHWARD...A SURFACE
LOW IS EXPECTED TO BE NEAR THE SD/NE/IA JUNCTURE. THERE IS A
PRETTY CONSISTENT SIGNAL THAT LOW LEVEL MOISTURE WILL BE PULLED
SOUTH INTO NORTHERN NEBRASKA BEHIND THE LOW. EXPECTING TO SEE
LOWERED CEILINGS AND VISIBILITIES IN THE VICINITY OF 12Z AT KVTN
WITH IFR/MVFR CEILINGS CONTINUING INTO THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 358 AM CST SUN DEC 11 2011/
DISCUSSION...
A PRETTY INVOLVED FORECAST IS TAKING SHAPE FOR MID WEEK AS MEDIUM
RANGE MODELS ALL INDICATE A TROUGH DIGGING DOWN THE WEST COAST OF
NORTH AMERICA...THEN EJECTING ACROSS THE FOUR CORNERS REGION TOWARD
THE PLAINS. INCONSISTENCY FROM RUN TO RUN IN HOW THE MODELS
EVENTUALLY EJECT THE SYSTEM HAVE CREATED LOW CONFIDENCE AT THIS
POINT IN TIME...ESPECIALLY CONCERNING PRECIPITATION TYPE...AS
RAIN...FREEZING RAIN AND SNOW WOULD ALL BE WITHIN THE REALM OF
POSSIBILITY. BUT BEFORE DIVING INTO THE MID WEEK SYSTEM...THE
FORECAST TODAY MAY BE TRICKY AS WELL. NEAR TERM SOLUTIONS ARE
PICKING UP ON A THIN ENVELOPE OF BL MOISTURE...PROBABLY FROM THE
EXTENSIVE ERODING SNOW PACK THAT RESIDES FROM SOUTHWEST TO
NORTHEAST NEBRASKA...AND TO A GREATER EXTENT...MOISTURE ADVECTION
FROM THE SOUTH. SEVERAL OF THE NEAR/SHORT TERM SOLUTIONS SUCH AS
THE HRRR AND NAM DEVELOP STRATUS TODAY ACROSS OUR SOUTHEASTERN
ZONES...WHICH WOULD LIMIT AFTERNOON HIGHS AOB THE MELTING POINT.
IN FACT...MET GUIDANCE IS SUGGESTING A HIGH OF JUST 30F THIS
AFTERNOON AT LBF...COMPARED TO THE MAV GUIDANCE OF 39F. GENERALLY
SIDED TOWARD THE WARMER GUIDANCE OUTPUT...WITH EXPECTED HIGHS ACROSS
OUR SOUTHEASTERN ZONES IN THE MID TO UPPER 30S. THIS IS BASED OFF
OF RECENT SATELLITE TRENDS OF THE LOWER CEILING BUILDING EAST...AND
THAT THE 00Z NAM INDICATES THAT THE 30-60 AGL MB RH IS NOT
SATURATED. ACROSS FAR NORTHWEST NEBRASKA...DRIER BL RH WILL AID
IN WARMING AFTERNOON T/S IN THE LOW TO MID 40S ONCE AGAIN.
A WEAK BOUNDARY SLIDES THROUGH THE CWA EARLY ON MONDAY COOLING
TEMPERATURES BACK INTO THE 30S CWA WIDE...WITH LOWS MONDAY MORNING
RETURNING INTO THE TEENS AND LOW 20S. BUFR SOUNDINGS CONTINUE TO
INDICATE A THIN ENVELOPE OF MOISTURE NEAR THE SURFACE EARLY MONDAY
MORNING WHICH COULD LEAD TO THE FORMATION OF PATCHY LOW FOG...WILL
CARRY THE MENTION OF -FG GENERALLY SOUTHEAST OF A CHAMBERS TO NORTH
PLATTE LINE...WHERE SLIGHTLY STRONGER MOISTURE TRANSPORT FROM THE
GULF WILL CREATE A DEEPER SATURATED PROFILE.
EARLY TUESDAY MORNING IS WHEN THINGS POTENTIALLY GET INTERESTING.
DEEPER MOISTURE TRANSPORT ON THE 280K THROUGH 290K ISENTROPIC
SURFACES COULD BRING SOME LIGHT QPF INTO CENTRAL...AND SOUTH CENTRAL
NEBRASKA. CROSS SECTIONS...WITH SUPPORT FROM BUFR SOUNDINGS
CONTINUE TO INDICATE THE TOP OF THE SATURATED LAYER SLIGHTLY ABOVE
0C...BUT COOLING RAPIDLY TOWARD THE SURFACE. NOT SEEING INITIALLY
ANY SEEDER FEEDER PROCESSES GOING...SO DRIZZLE OR LIGHT FREEZING
RAIN WOULD BE THE EXPECTED PTYPE EARLY ON TUESDAY. HOWEVER
CONDITIONS WILL DETERIORATE THROUGH THE DAY...AS DEEPER MOISTURE AND
BETTER FORCING ARRIVES WITH THE EJECTING WAVE. THE NAM....GFS AND
EURO ALL NOW INDICATE PROFILES FAVORABLE FOR FREEZING RAIN ACROSS
OUR SOUTHEASTERN ZONE BY 00Z WEDNESDAY. MODELS BEGIN TO DIVERGE
FROM THERE ON...AS THE GFS AND NAM CONTINUE TO BE PROGRESSIVE BY
PHASING WITH THE NORTHERN STREAM...WHEREAS THE EUROPEAN CAMP HAS
REVERTED BACK TO A CLOSED NEGATIVELY TILTED H5 LOW. THE QUICKER
SOLUTIONS WOULD INDICATE THE BULK OF THE PRECIPITATION THAT WOULD
FALL WOULD BE AS FREEZING RAIN...ESPECIALLY FOR LOCATIONS EAST OF A
NORTH PLATTE TO AINSWORTH LINE. HOWEVER...THE SLOWER SOLUTION WOULD
ALLOW FOR MORE COOLER AIR TO BE DRAWN INTO THE SYSTEM...THUS FORCING
A QUICKER CHANGE OVER TO SNOW...WITH POSSIBLY SIGNIFICANT
ACCUMULATIONS. SINCE THERE CONTINUES TO BE INCONSISTENCY WITH RUN
TO RUN SOLUTIONS...AND SIGNIFICANT DIFFERENCES IN THE EVENTUAL
OUTCOME OF THE SYSTEM WHEN IT REACHES THE PLAINS...FELT IT WAS BEST
TO CARRY FORWARD LOW END CHANCE/SLIGHT CHANCE POPS FOR MUCH OF THE
CWA TUESDAY NIGHT THROUGH EARLY THURSDAY...LEAVING THE HIGHEST POPS
TARGETING OUR EASTERN ZONES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
539 AM CST SUN DEC 11 2011
.AVIATION...
FOR THE KLBF AND KVTN TERMINALS THROUGH 12Z MONDAY.
ALONG AND EAST OF A LINE FROM KBBW TO KONL TODAY...FOG AND STRATUS
ARE POSSIBLE WITH CIGS BLO 1000 FT AGL AND VISBYS DOWN TO 3SM. WEST OF
THIS LINE TO A LINE EXTENDING FROM KIML...TO KLBF...TO 40W OF
KONL...PATCHY FOG IS POSSIBLE THROUGH MID MORNING WITH VISBYS DOWN
TO 3 SM. AFTER MID MORNING...FOG SHOULD BURN OFF...WITH THE
EXCEPTION OF LOCATIONS EAST OF A LINE FROM KBBW TO KONL WHERE
STRATUS MAY PERSIST TODAY INTO TONIGHT. ELSEWHERE...UNLIMITED
CEILINGS ARE FORECAST WITH SOME PATCHY FOG DEVELOPMENT POSSIBLE
AFTER 06Z MONDAY ACROSS SWRN AND CENTRAL NEBRASKA. WINDS AT THE KLBF AND
KVTN TERMINALS WILL BE FROM THE SOUTHWEST AND WEST TODAY AT UNDER
10 KTS. WINDS WILL SHIFT TO THE WEST AND NORTHWEST OVERNIGHT
TONIGHT...WITH SPEEDS EXPECTED TO REMAIN AT OR BLO 10 KTS.
&&
PREV DISCUSSION... /ISSUED 358 AM CST SUN DEC 11 2011/
DISCUSSION...
A PRETTY INVOLVED FORECAST IS TAKING SHAPE FOR MID WEEK AS MEDIUM
RANGE MODELS ALL INDICATE A TROUGH DIGGING DOWN THE WEST COAST OF
NORTH AMERICA...THEN EJECTING ACROSS THE FOUR CORNERS REGION TOWARD
THE PLAINS. INCONSISTENCY FROM RUN TO RUN IN HOW THE MODELS
EVENTUALLY EJECT THE SYSTEM HAVE CREATED LOW CONFIDENCE AT THIS
POINT IN TIME...ESPECIALLY CONCERNING PRECIPITATION TYPE...AS
RAIN...FREEZING RAIN AND SNOW WOULD ALL BE WITHIN THE REALM OF
POSSIBILITY. BUT BEFORE DIVING INTO THE MID WEEK SYSTEM...THE
FORECAST TODAY MAY BE TRICKY AS WELL. NEAR TERM SOLUTIONS ARE
PICKING UP ON A THIN ENVELOPE OF BL MOISTURE...PROBABLY FROM THE
EXTENSIVE ERODING SNOW PACK THAT RESIDES FROM SOUTHWEST TO
NORTHEAST NEBRASKA...AND TO A GREATER EXTENT...MOISTURE ADVECTION
FROM THE SOUTH. SEVERAL OF THE NEAR/SHORT TERM SOLUTIONS SUCH AS
THE HRRR AND NAM DEVELOP STRATUS TODAY ACROSS OUR SOUTHEASTERN
ZONES...WHICH WOULD LIMIT AFTERNOON HIGHS AOB THE MELTING POINT.
IN FACT...MET GUIDANCE IS SUGGESTING A HIGH OF JUST 30F THIS
AFTERNOON AT LBF...COMPARED TO THE MAV GUIDANCE OF 39F. GENERALLY
SIDED TOWARD THE WARMER GUIDANCE OUTPUT...WITH EXPECTED HIGHS ACROSS
OUR SOUTHEASTERN ZONES IN THE MID TO UPPER 30S. THIS IS BASED OFF
OF RECENT SATELLITE TRENDS OF THE LOWER CEILING BUILDING EAST...AND
THAT THE 00Z NAM INDICATES THAT THE 30-60 AGL MB RH IS NOT
SATURATED. ACROSS FAR NORTHWEST NEBRASKA...DRIER BL RH WILL AID
IN WARMING AFTERNOON T/S IN THE LOW TO MID 40S ONCE AGAIN.
A WEAK BOUNDARY SLIDES THROUGH THE CWA EARLY ON MONDAY COOLING
TEMPERATURES BACK INTO THE 30S CWA WIDE...WITH LOWS MONDAY MORNING
RETURNING INTO THE TEENS AND LOW 20S. BUFR SOUNDINGS CONTINUE TO
INDICATE A THIN ENVELOPE OF MOISTURE NEAR THE SURFACE EARLY MONDAY
MORNING WHICH COULD LEAD TO THE FORMATION OF PATCHY LOW FOG...WILL
CARRY THE MENTION OF -FG GENERALLY SOUTHEAST OF A CHAMBERS TO NORTH
PLATTE LINE...WHERE SLIGHTLY STRONGER MOISTURE TRANSPORT FROM THE
GULF WILL CREATE A DEEPER SATURATED PROFILE.
EARLY TUESDAY MORNING IS WHEN THINGS POTENTIALLY GET INTERESTING.
DEEPER MOISTURE TRANSPORT ON THE 280K THROUGH 290K ISENTROPIC
SURFACES COULD BRING SOME LIGHT QPF INTO CENTRAL...AND SOUTH CENTRAL
NEBRASKA. CROSS SECTIONS...WITH SUPPORT FROM BUFR SOUNDINGS
CONTINUE TO INDICATE THE TOP OF THE SATURATED LAYER SLIGHTLY ABOVE
0C...BUT COOLING RAPIDLY TOWARD THE SURFACE. NOT SEEING INITIALLY
ANY SEEDER FEEDER PROCESSES GOING...SO DRIZZLE OR LIGHT FREEZING
RAIN WOULD BE THE EXPECTED PTYPE EARLY ON TUESDAY. HOWEVER
CONDITIONS WILL DETERIORATE THROUGH THE DAY...AS DEEPER MOISTURE AND
BETTER FORCING ARRIVES WITH THE EJECTING WAVE. THE NAM....GFS AND
EURO ALL NOW INDICATE PROFILES FAVORABLE FOR FREEZING RAIN ACROSS
OUR SOUTHEASTERN ZONE BY 00Z WEDNESDAY. MODELS BEGIN TO DIVERGE
FROM THERE ON...AS THE GFS AND NAM CONTINUE TO BE PROGRESSIVE BY
PHASING WITH THE NORTHERN STREAM...WHEREAS THE EUROPEAN CAMP HAS
REVERTED BACK TO A CLOSED NEGATIVELY TILTED H5 LOW. THE QUICKER
SOLUTIONS WOULD INDICATE THE BULK OF THE PRECIPITATION THAT WOULD
FALL WOULD BE AS FREEZING RAIN...ESPECIALLY FOR LOCATIONS EAST OF A
NORTH PLATTE TO AINSWORTH LINE. HOWEVER...THE SLOWER SOLUTION WOULD
ALLOW FOR MORE COOLER AIR TO BE DRAWN INTO THE SYSTEM...THUS FORCING
A QUICKER CHANGE OVER TO SNOW...WITH POSSIBLY SIGNIFICANT
ACCUMULATIONS. SINCE THERE CONTINUES TO BE INCONSISTENCY WITH RUN
TO RUN SOLUTIONS...AND SIGNIFICANT DIFFERENCES IN THE EVENTUAL
OUTCOME OF THE SYSTEM WHEN IT REACHES THE PLAINS...FELT IT WAS BEST
TO CARRY FORWARD LOW END CHANCE/SLIGHT CHANCE POPS FOR MUCH OF THE
CWA TUESDAY NIGHT THROUGH EARLY THURSDAY...LEAVING THE HIGHEST POPS
TARGETING OUR EASTERN ZONES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
358 AM CST SUN DEC 11 2011
.DISCUSSION...
A PRETTY INVOLVED FORECAST IS TAKING SHAPE FOR MID WEEK AS MEDIUM
RANGE MODELS ALL INDICATE A TROUGH DIGGING DOWN THE WEST COAST OF
NORTH AMERICA...THEN EJECTING ACROSS THE FOUR CORNERS REGION TOWARD
THE PLAINS. INCONSISTENCY FROM RUN TO RUN IN HOW THE MODELS
EVENTUALLY EJECT THE SYSTEM HAVE CREATED LOW CONFIDENCE AT THIS
POINT IN TIME...ESPECIALLY CONCERNING PRECIPITATION TYPE...AS
RAIN...FREEZING RAIN AND SNOW WOULD ALL BE WITHIN THE REALM OF
POSSIBILITY. BUT BEFORE DIVING INTO THE MID WEEK SYSTEM...THE
FORECAST TODAY MAY BE TRICKY AS WELL. NEAR TERM SOLUTIONS ARE
PICKING UP ON A THIN ENVELOPE OF BL MOISTURE...PROBABLY FROM THE
EXTENSIVE ERODING SNOW PACK THAT RESIDES FROM SOUTHWEST TO
NORTHEAST NEBRASKA...AND TO A GREATER EXTENT...MOISTURE ADVECTION
FROM THE SOUTH. SEVERAL OF THE NEAR/SHORT TERM SOLUTIONS SUCH AS
THE HRRR AND NAM DEVELOP STRATUS TODAY ACROSS OUR SOUTHEASTERN
ZONES...WHICH WOULD LIMIT AFTERNOON HIGHS AOB THE MELTING POINT.
IN FACT...MET GUIDANCE IS SUGGESTING A HIGH OF JUST 30F THIS
AFTERNOON AT LBF...COMPARED TO THE MAV GUIDANCE OF 39F. GENERALLY
SIDED TOWARD THE WARMER GUIDANCE OUTPUT...WITH EXPECTED HIGHS ACROSS
OUR SOUTHEASTERN ZONES IN THE MID TO UPPER 30S. THIS IS BASED OFF
OF RECENT SATELLITE TRENDS OF THE LOWER CEILING BUILDING EAST...AND
THAT THE 00Z NAM INDICATES THAT THE 30-60 AGL MB RH IS NOT
SATURATED. ACROSS FAR NORTHWEST NEBRASKA...DRIER BL RH WILL AID
IN WARMING AFTERNOON T/S IN THE LOW TO MID 40S ONCE AGAIN.
A WEAK BOUNDARY SLIDES THROUGH THE CWA EARLY ON MONDAY COOLING
TEMPERATURES BACK INTO THE 30S CWA WIDE...WITH LOWS MONDAY MORNING
RETURNING INTO THE TEENS AND LOW 20S. BUFR SOUNDINGS CONTINUE TO
INDICATE A THIN ENVELOPE OF MOISTURE NEAR THE SURFACE EARLY MONDAY
MORNING WHICH COULD LEAD TO THE FORMATION OF PATCHY LOW FOG...WILL
CARRY THE MENTION OF -FG GENERALLY SOUTHEAST OF A CHAMBERS TO NORTH
PLATTE LINE...WHERE SLIGHTLY STRONGER MOISTURE TRANSPORT FROM THE
GULF WILL CREATE A DEEPER SATURATED PROFILE.
EARLY TUESDAY MORNING IS WHEN THINGS POTENTIALLY GET INTERESTING.
DEEPER MOISTURE TRANSPORT ON THE 280K THROUGH 290K ISENTROPIC
SURFACES COULD BRING SOME LIGHT QPF INTO CENTRAL...AND SOUTH CENTRAL
NEBRASKA. CROSS SECTIONS...WITH SUPPORT FROM BUFR SOUNDINGS
CONTINUE TO INDICATE THE TOP OF THE SATURATED LAYER SLIGHTLY ABOVE
0C...BUT COOLING RAPIDLY TOWARD THE SURFACE. NOT SEEING INITIALLY
ANY SEEDER FEEDER PROCESSES GOING...SO DRIZZLE OR LIGHT FREEZING
RAIN WOULD BE THE EXPECTED PTYPE EARLY ON TUESDAY. HOWEVER
CONDITIONS WILL DETERIORATE THROUGH THE DAY...AS DEEPER MOISTURE AND
BETTER FORCING ARRIVES WITH THE EJECTING WAVE. THE NAM....GFS AND
EURO ALL NOW INDICATE PROFILES FAVORABLE FOR FREEZING RAIN ACROSS
OUR SOUTHEASTERN ZONE BY 00Z WEDNESDAY. MODELS BEGIN TO DIVERGE
FROM THERE ON...AS THE GFS AND NAM CONTINUE TO BE PROGRESSIVE BY
PHASING WITH THE NORTHERN STREAM...WHEREAS THE EUROPEAN CAMP HAS
REVERTED BACK TO A CLOSED NEGATIVELY TILTED H5 LOW. THE QUICKER
SOLUTIONS WOULD INDICATE THE BULK OF THE PRECIPITATION THAT WOULD
FALL WOULD BE AS FREEZING RAIN...ESPECIALLY FOR LOCATIONS EAST OF A
NORTH PLATTE TO AINSWORTH LINE. HOWEVER...THE SLOWER SOLUTION WOULD
ALLOW FOR MORE COOLER AIR TO BE DRAWN INTO THE SYSTEM...THUS FORCING
A QUICKER CHANGE OVER TO SNOW...WITH POSSIBLY SIGNIFICANT
ACCUMULATIONS. SINCE THERE CONTINUES TO BE INCONSISTENCY WITH RUN
TO RUN SOLUTIONS...AND SIGNIFICANT DIFFERENCES IN THE EVENTUAL
OUTCOME OF THE SYSTEM WHEN IT REACHES THE PLAINS...FELT IT WAS BEST
TO CARRY FORWARD LOW END CHANCE/SLIGHT CHANCE POPS FOR MUCH OF THE
CWA TUESDAY NIGHT THROUGH EARLY THURSDAY...LEAVING THE HIGHEST POPS
TARGETING OUR EASTERN ZONES.
&&
.AVIATION...
OR THE KLBF AND KVTN TERMINALS THROUGH 12Z MONDAY.
ALONG AND EAST OF A LINE FROM KBBW TO KONL TODAY...FOG AND STRATUS
ARE POSSIBLE WITH CIGS BLO 1000 FT AGL AND VISBYS BLO 1SM IN FOG.
WEST OF THIS LINE TO A LINE EXTENDING FROM KIML...TO KLBF...TO 40W
OF KONL...PATCHY FOG IS POSSIBLE THROUGH MID MORNING WITH VISBYS
DOWN TO 1 TO 3 SM. AFTER MID MORNING...FOG SHOULD BURN OFF...WITH
THE EXCEPTION OF LOCATIONS EAST OF A LINE FROM KBBW TO KONL. IN
THESE AREAS...IF STRATUS DOES DEVELOP...IT IS EXPECTED TO PERSIST
TODAY AND INTO TONIGHT. ELSEWHERE...UNLIMITED CEILINGS ARE FORECAST
WITH SOME PATCHY FOG DEVELOPMENT POSSIBLE AFTER 06Z MONDAY. WINDS AT
THE KLBF AND KVTN TERMINALS WILL BE FROM THE SOUTHWEST AND WEST
TODAY AT UNDER 10 KTS. WINDS WILL SHIFT TO THE WEST AND NORTHWEST
OVERNIGHT TONIGHT...WITH SPEEDS EXPECTED TO REMAIN AT OR BLO 10 KTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1117 PM CST SAT DEC 10 2011
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
LOW CLOUDS WITH REDUCED VISIBILITIES HAD REACHED NEAR A HSI-BIE-
FNB LINE AT 0515Z AND WILL SPREAD ACROSS TAF SITES IN 07Z-10Z
PERIOD. 06Z FORECAST INCLUDED CIGS BELOW 1K FT AGL WITH
VISIBILITIES IN 3-4SM RANGE. IN ADDITION...WIND SHEAR FROM
PREVIOUS FORECAST WAS CONTINUED AS LOW LEVEL WINDS REMAIN BRISK
ABOVE THE SURFACE. BREAKS IN CLOUD DECK OVER CENTRAL KANSAS COULD
ALLOW FOR SOME IMPROVEMENT SUNDAY MORNING AND THIS WAS REFLECTED
IN FORECAST. HOWEVER...AREA COULD FILL IN AS THE NIGHT PROGRESSES
AND TRENDS WILL CONTINUE TO BE MONITORED. ANY IMPROVEMENT WILL BE
SHORT-LIVED AS EVEN MORE MOISTURE WILL MOVE INTO ERN NEBRASKA LATE
SUNDAY BRINGING DETERIORATING CONDITIONS. DRIZZLE OR FREEZING
DRIZZLE COULD ALSO DEVELOP...BUT WAS NOT MENTIONED IN THIS TAF
CYCLE.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 836 PM CST SAT DEC 10 2011/
UPDATE...
UPDATED FOR INCREASING CLOUDS TONIGHT SRN ZONES.
DISCUSSION...
LOW CLOUDS IN KANSAS CONTINUE TO PUSH NE AND SATELLITE TRENDS
PLUS LOW LEVEL RH FORECAST FROM HRRR INDICATED FOR THIS TO
CONTINUE. THUS INCREASED SKY GRIDS SRN 1/2 LATER TONIGHT INTO
SUNDAY MORNING. BUMPED UP LOWS A FEW DEGREES SOME AREAS BECAUSE OF
CLOUDS BUT WITH SNOW COVER ANY DECREASE IN WINDS COULD ALLOW THEM
TO QUICKLY FALL PER 02Z LNK OR EARLIER OFF/TQE. CLOUDS ALSO
CONTINUE TO HAVE A BACK EDGE SO DID NOT KEEP SUNDAY MOCLOUDY ALL
DAY...WITH SOME MIXING OR MOVING OUT POSSIBLE BUT THIS WILL BE
FURTHER ADDRESSED WITH OVERNIGHT FORECAST.
AVIATION...
LOW CLOUDS WITH IFR CEILINGS CONTINUE TO ADVANCE NEWD AND NOW
APPEAR LIKELY TO IMPACT KLNK A LITTLE AROUND 07Z AND OMAHA BETWEEN
08Z AND 09Z. AMD TO FOLLOW.
CHERMOK
PREV DISCUSSION... /ISSUED 520 PM CST SAT DEC 10 2011/
AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
CONTINUED SRLY LOW LEVEL FLOW WILL ATTEMPT TO PULL IN LOW LEVEL
MOISTURE LATE TONIGHT AND LOW CLOUDS CURRENTLY OVER KS COULD
MAKE IT INTO SERN NEBR BY SUNDAY MORNING. ALTHOUGH WITH THE 00Z
FORECAST CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE CEILINGS UNTIL
LATE SUNDAY AFTERNOON WHEN CONTINUED LOW CLOUD DEVELOPMENT +
ADVECTION SHOULD BRING CEILINGS NEAR IFR LEVELS TO TAF SITES. IN
ADDITION...SNOW COVER WILL KEEP STRONGER LOW LEVEL WINDS ABOVE
INVERSION FROM MIXING DOWN WHICH NOT ONLY COULD PROVIDE WIND SHEAR
TO SITES LATER TONIGHT INTO SUNDAY...BUT ALSO ALLOW SOME FOG TO
DEVELOP AGAIN. BOTH WERE MENTIONED IN TAF FORECASTS. HOWEVER...IT
APPEARS WITH WINDS A LITTLE STRONGER THAN YESTERDAY VISIBILITIES
SHOULD NOT DROP AS LOW AS LAST NIGHT.
CHERMOK
PREV DISCUSSION... /ISSUED 404 PM CST SAT DEC 10 2011/
SHORT TERM...TONIGHT THROUGH TUESDAY.
FORECAST CONCERNS WILL BE TEMPERATURES AND PATCHY FOG
TONIGHT...THEN INCREASING LOW LEVEL MOISTURE AND LIGHT
PRECIPITATION AND PRECIPITATION TYPE SUNDAY AFTERNOON THROUGH
TUESDAY.
TEMPERATURES LAST NIGHT REALLY DROPPED OFF AFTER SUNSET WITH THE
LIGHT WINDS AND AGAIN WENT BELOW GUIDANCE. HARD TO SAY HOW COLD
SPECIFIC LOCATIONS WILL GET WITH VARIABLE CONDITIONS AND SNOW
PACK...BUT WITH HIGHER DEWPOINTS AND SOME MELTING DO NOT THINK IT
WILL BE AS COLD...BUT SHOULD AGAIN HAVE SOME PATCHY FOG.
LOW LEVEL STRATUS IN KS AND WITH INCREASING SOUTHWEST FLOW...WILL
LOOK FOR THIS STRATUS TO RETURN TO NEBRASKA SUNDAY. THE STORM
SYSTEM OVER THE ROCKIES WILL MOVE INTO NEBRASKA DURING THE DAY.
FOR NOW HAVE THE STRATUS COMING IN SUNDAY AFTERNOON AS ISENTROPIC
LIFT SATURATES THE 280 DEG SFC. ALSO ADDED SOME PATCHY FOG AS THE
HIGHER DEWPOINTS COME IN. TEMPERATURES WILL BE TOUGH WITH
SNOWCOVER AND CLOUDS MOVING IN. HAVE HIGHS MOSTLY FROM 34 TO 38
AND IN THE 40S ACROSS THE SOUTH. OVERNIGHT...CONDITIONS
DETERIORATE WITH MOISTURE DEEPENING AND DRIZZLE/FREEZING
DRIZZLE/LIGHT PRECIPITATION DEVELOPS. PRECIPITATION TYPE WILL DEPEND
ON THE SURFACE TEMPERATURES. THE EC/GFS HAVE BEEN TOO WARM ON
TEMPS WITH THE SNOWPACK AND THE NAM WAS BETTER. TENDED TOWARD THE
NAM TEMPS VERSUS WARMER EC/GFS FOR THIS PKG. LOWS ALONG AND NORTH
OF I80 DROP TO FREEZING OR BELOW AND SOUTH OF THIS LINE KEEP LOWS
ABOVE FREEZING. THE LIGHT PRECIPITATION CONTINUES AHEAD OF THE
SURFACE FRONT MONDAY. LINGERED THE PRECIPITATION INTO TUESDAY
ACROSS THE SOUTH AS THE DEEP MOISTURE DOES NOT GET SCOURED OUT AND
THERE IS A SURGE OF LOW LEVEL MOISTURE WITH THE MID LEVEL TROF
STILL OVER THE SOUTHWEST U.S.
ZAPOTOCNY
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
MAJORITY OF MEDIUM RANGE MODELS LOOK SIMILAR IN MOVING UPPER TROUGH
FROM THE WESTERN U.S. THROUGH THE PLAINS WEDNESDAY INTO THURSDAY.
HOWEVER ECMWF AND GFS HAVE ONE MAJOR DIFFERENCE THAT CAUSES
DIVERGING SENSIBLE WEATHER SOLUTIONS FOR OUR AREA. WHILE BOTH EJECT
MAIN LOW/TROUGH WITH SIMILAR TIMING...THE GFS DRIVES A SIGNIFICANT
SHORTWAVE INTO THE NORTHERN PLAINS AHEAD OF MAIN TROUGH. THIS
FEATURE SUPPRESSES SURFACE LOW TRACK MUCH FARTHER SOUTH...INCLUDING
ASSOCIATED PRECIPITATION...AND KEEPS OUR AREA IN COLDER TEMPERATURE
REGIME. THE ECMWF ALSO MOVES A SHORTWAVE INTO THE NORTHERN
PLAINS...BUT ITS WAVE IS MINOR AND PROGRESSIVE WITH LITTLE AFFECT
HERE. WILL FOLLOW THE LEAD OF HPC AND PREVIOUS FORECAST AND SIDE
MORE CLOSELY WITH THE ECMWF SOLUTION.
SURGE OF MOISTURE WILL SPREAD INTO OUR SOUTHERN CWA TUESDAY
NIGHT...WITH SURFACE TEMPERATURES HOLDING ABOVE FREEZING AND
FORECAST SOUNDINGS SUGGESTING RAIN THE MOST LIKELY TYPE. RAIN
CHANCES INCREASE WEDNESDAY AS SURFACE LOW MOVES INTO THE AREA. COULD
SEE DRY SLOT CLEARING IN THE SOUTH...ALLOWING TEMPERATURES TO REALLY
CLIMB. AS COLDER AIR SPILLS IN BEHIND EXITING SYSTEM LATE WEDNESDAY
NIGHT AND THURSDAY...RAIN CHANGING TO SNOW IS PROBABLE IN OUR
NORTHWEST. HOWEVER WITH PROGRESSIVE SYSTEM...NOT EXPECTING
SIGNIFICANT SNOWFALL RIGHT NOW. TEMPERATURES WILL SETTLE BACK INTO
THE 30S THURSDAY THEN LIKELY 20S ON FRIDAY. HOWEVER ECMWF SHOWS
A CLIPPER SYSTEM APPROACHING FOR FRIDAY NIGHT AND SATURDAY THAT WILL
TURN WINDS TO THE SOUTH AND SOUTHEAST...SO HIGHS FRIDAY COULD BE
EASILY MAKE THE 30S. AND LIGHT SNOW IS POSSIBLE FRIDAY NIGHT AND
SATURDAY WITH THAT CLIPPER...BUT WILL HOLD OFF MENTION UNTIL SOME
CONSISTENCY BETWEEN VARIED MODEL SOLUTIONS IS REALIZED.
DERGAN
AVIATION...
18Z TAFS FOR KOMA...KLNK...KOFK.
HIGH CONFIDENCE AT THIS POINT THAT LLWS WILL BE AN ISSUE AT ALL SITES
BEGINNING LATER THIS EVENING. APPEARS THAT WIND SHEAR WILL INCREASE
TO 40-45KT AT FL015 AGL TOWARD 11/03Z...AND PERSIST THROUGH THE END
OF THE FCST PD. OTHERWISE VFR IS EXPECTED FOR THE DURATION OF THE
FCST PD.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
830 PM CST MON DEC 12 2011
.DISCUSSION...FORECAST HEADACHE TONIGHT WILL BE CLOUD TRENDS AND
RELATED TEMPERATURES. CLEAR SLOT ROUGHLY ALONG AND WEST OF VALLEY
ASSOCIATED WITH RIDGE OF HIGH PRESSURE AND RELATIVELY DRY E-NE FLOW
AT CLOUD LAYER. RUC HANDLING CLEARING BEST AT THIS POINT. SPC MESO
ANALYSIS INDICATING 925 MB FLOW BECOMING MORE E VS NE WHICH WOULD
LIMIT ANY CLEARING TO WESTERN FA. AFT 06Z FLOW TRENDS TO THE EAST
AND THEN SE TOWARDS MORNING. WITH THIS ANTICIPATED LOW LEVEL FLOW
EXPECT AREAS ALONG AND EAST OF VALLEY TO REMAIN IN CLOUDS OVERNIGHT
WITH WESTERN AREAS GRADUALLY FILLING IN TOWARDS MORNING.
TEMPERATURES ACROSS FA VARY DEPENDING ON DEGREE OF CLEARING. EXPECT
COLDEST AREAS WEST OF VALLEY IN LIGHT WIND AND CLEAR CONDITIONS.
WARMEST VALUES WILL BE ACROSS FAR EAST WITH HIGHER DEWPOINTS. FOG
COULD ALSO BE AN ISSUE LATER TONIGHT. WILL MAINTAIN MENTION IN
HIGHER LOW LEVEL MOISTURE ACROSS SE FA HOWEVER COULD SEE SOME ABOUT
ANYWHERE.
&&
.AVIATION...MVFR/IFR CIGS ACROSS ALL BUT NARROW AREA JUST WEST OF
VALLEY. AREAS IN THE CLOUDS LIKELY TO REMAIN SO WITH CLEAR AREAS
GRADUALLY FILLING IN TOWARDS MORNING. NO FOG AS OF YET HOWEVER
EXPECT DEVELOPMENT ACROSS SE FA WHERE DEWPOINTS HIGHER. ELSEWHERE
CANNOT RULE OUT PATCHY BR WITH LIGHT WINDS BUT LIKELY MORE SPOTTY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
VOELKER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
930 PM EST MON DEC 12 2011
.SYNOPSIS...
HIGH PRESSURE IN CONTROL INTO TUESDAY. A WEAK WARM FRONT LIFTS TO
OUR NORTH ON WEDNESDAY. COLD FRONT CROSSES ON THURSDAY. DEEPER
MOISTURE MAY KINK BACK NORTH AND BRUSH AREA LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOWER CLOUDS HAVE MADE IT UP TO ROUGHLY I-64. RUC SEEMS TO HAVE A
GOOD HANDLE ON THE H850 MOISTURE...AND THE MODEL PREDICTS THAT NOT
MUCH MORE NORTHWARD PROGRESS IS EXPECTED OVERNIGHT. SO...HAVE
UPDATED GRIDS TO LINGER LOWER CLOUDS ACROSS THE SOUTH THROUGH 12Z
BEFORE ALLOWING THEM TO DECREASE AFTER SUNRISE. ONLY PATCHES OF
HIGHER CLOUDS WILL BE SEEN ACROSS THE NORTH.
AS FOR TEMPERATURES...UPPED OVERNIGHT LOWS A FEW DEGREES ACROSS THE
SOUTH DUE TO THICKER CLOUDS...BACK TO OR ABOVE FREEZING IN A FEW
CASES. NOT MUCH CHANGE IN LOWS ACROSS THE NORTH.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
FOR THESE LONG DECEMBER NIGHTS...MINIMUM TEMPERATURES ARE CERTAINLY
NOTICEABLY ABOVE NORMAL FOR THIS PERIOD.
ONLY MINOR CHANGES WITH THE WARM FRONT FOLLOWED BY COLD FRONT
COMBO. WENT A BIT FURTHER SOUTH ON THE MEASURABLE CHANCE POPS LATE
TUESDAY NIGHT INTO WEDNESDAY AND HAVE A 60 LIKELY POP BRUSHING PERRY
COUNTY NEAR DAWN ON WEDNESDAY ASSOCIATED WITH THE WARM FRONT. HAVE
A RENEGADE 20 SLIGHT CHANCE POP REACHING AS FAR EAST AS AROUND OUR
MOUNTAIN VALLEYS IN THE ELKINS VICINITY BY DAWN WEDNESDAY. SO COULD
NOT COMPLETELY RULE OUT SOME POCKET OF FREEZING RAIN...BUT AGAIN
POPS NOT HIGH...THAT FAR EAST.
TRIED TO LIFT NORTH THE HOURLY POPS NORTH AND DRY OUT ENTIRE CWA BY
00Z THURSDAY. 12Z GFS TEMPERATURE GUIDANCE SEEMS TOO COLD FOR
WEDNESDAY NIGHT...EVEN WITH THE CLOUDS THINNING FOR A WHILE FOR
WEDNESDAY EVENING.
WITH THE 50 KNOT 700 MB STEERING CURRENT. BROUGHT BACK THE PRE COLD
FRONTAL SHOWERY POPS BEFORE 12Z THURSDAY IN NE KENTUCKY AND
SOUTHEAST OHIO...THEN SWINGING THROUGH WV AND SW VA 12Z THURSDAY TO
00Z FRIDAY. THE SURFACE FRONT LAGS BEHIND...SO LEFT CHANCE POPS
UNTIL FRONT PASSES AROUND OR AFTER 00Z FRIDAY.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE TO BUILD IN AFTER FRONTAL PASSAGE THURSDAY
NIGHT...WITH A COOLER AIRMASS TO SETTLE IN FOR THE WEEKEND. WITH
ATLANTIC RIDGE/POSITIVE NAO REMAINING IN PLACE FOR THE FORESEEABLE
FUTURE...NOT EXPECTING ANYTHING IN TERMS OF ARCTIC OUTBREAKS. ANY
CHILLY DAYS OR NIGHTS SHOULD REBOUND TO NORMAL OR SLIGHTLY ABOVE
HEADING INTO EARLY NEXT WEEK. OPERATIONAL MODELS KEY ON A LOW
PRESSURE SYSTEM THAT WILL GET ORGANIZED OVER THE SOUTHERN PLAINS AND
PUSH NORTHEASTWARD. ALTHOUGH EXACT TRACKS HAVE SIGNIFICANT
SPREAD...THE TREND OF RISING 500MB HEIGHTS INTO MONDAY IS A DECENT
PLAY FOR THIS ISSUANCE.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
WEAK SHORTWAVE AND SOME LOW LEVEL MOISTURE RESPONSIBLE FOR 025-050
HEIGHT CLOUDS ACROSS SOUTHERN WEST VIRGINIA AND SOUTHWEST VIRGINIA.
THESE WILL PULL EAST WITH THE SHORTWAVE OVERNIGHT. ON
TUESDAY...WARM FRONTAL BOUNDARY DEVELOPS AND MOVES TOWARD CWA FROM
THE WEST. MID/UPPER CLOUDS WILL SLOWLY LOWER AND THICKEN DURING THE
AFTERNOON BUT MOSTLY REMAIN VFR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: NORTHWARD PROGRESS OF MVFR CLOUD DECK TONIGHT
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 12/13/11
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H M M M H H H M H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z WEDNESDAY...
IFR POSSIBLE IN RAIN SHOWERS WITH COLD FRONT THURSDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/26/JS
NEAR TERM...CL
SHORT TERM...KTB
LONG TERM...26
AVIATION...CL
AREA FORECAST DISCUSSION
NWS PENDLETON OR
955 AM PST SUN DEC 11 2011
.UPDATE...WATER VAPOR IMAGERY SHOWS A WEAK AND DISORGANIZED FRONT
CROSSING THE COLUMBIA BASIN AT THIS TIME WHILE A TROUGH FOLLOWS
BEHIND IT AT THE COAST LINE. THUS FAR THE FRONT IS NOT DOING MUCH TO
BREAK UP THE INVERSION AND CLOUD COVER OVER THE AREA. IT COULD STILL
HAPPEN AND THUS HAVE NOT MADE TOO MANY CHANGES TO THE FORECAST. MAIN
CONCERN IS THE EXTENT OF FREEZING FOG. CURRENTLY HAVE A FREEZING FOG
ADVISORY OUT FOR MOST OF THE COLUMBIA BASIN AND BLUE MOUNTAIN
FOOTHILLS AS WELL AS NORTH CENTRAL OREGON. HAVE TRIMMED BACK
FREEZING FOG IN NORTH CENTRAL OREGON TO NORTH OF THE JEFFERSON
COUNTY LINE AS MADRAS IS SHOWING PARTLY CLOUDY SKIES WHILE WASCO
OBSERVATIONS STILL LOOK SATURATED. THE OREGON COLUMBIA BASIN IS
CURRENTLY NOT UNDER A FREEZING FOG ADVISORY. HERMISTON OBSERVATIONS
HAVE NOT DROPPED BELOW 1/2 MILE AND WEBCAMS IN THE ZONE DO NOT LOOK
AS LOW AS 1/4 MILE SO WILL NOT ISSUE A FREEZING FOG ADVISORY THERE
UNLESS CONDITIONS DETERIORATE FURTHER. HAVE NO DOUBT THAT THERE ARE
SOME LOCATIONS IN THAT ZONE AT 1/4 MILE OR LESS BUT COVERAGE DOES
NOT LOOK WIDESPREAD ENOUGH. HOWEVER, THE KITTITAS VALLEY DOES LOOK
LIKE IT HAS WIDESPREAD FREEZING FOG SO WILL ISSUE A FREEZING FOG
ADVISORY THERE SHORTLY. OTHERWISE, FORECAST IS IN GOOD SHAPE AND
WILL MONITOR FOR AN UPDATE IF CLOUD COVER SHOWS SIGNS OF BREAKING
UP. IT HAS ALSO STARTED TO SNOW HERE IN PENDLETON SO WILL BE ADDING
A SLIGHT CHANCE OF SNOW SHOWERS TO THE BLUE MOUNTAIN FOOTHILLS ZONES
FOR TODAY.
LOOKING AHEAD TO TONIGHT, GFS AND NAM BOTH SHOW DEEP MOISTURE AND
ENOUGH SATURATION TO 8000-10000 FEET FOR LIGHT SNOW, PERHAPS UP TO
AN INCH, IN THE EASTERN COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS
TONIGHT WHILE THE ECMWF, SREF AND RUC SHOW LESS MOISTURE AND LITTLE
OR NO SNOW. HAVE TROUBLE BELIEVING THE DEGREE OF MOISTURE BUILD UP
IN THE GFS AND NAM, BUT AS IT HAS STARTED TO SNOW ALREADY AT
PENDLETON, AM TENDING TO TAKE IT MORE SERIOUSLY. WILL BE LOOKING AT
THIS IN MORE DETAIL FOR THE AFTERNOON FORECAST. PERRY
&&
.AVIATION...18Z TAFS. FOG AND STRATUS REMAIN IN THE COLUMBIA BASIN
AND ADJACENT VALLEYS...IMPACTING TAF SITES YKM PSC ALW PDT DLS.
IFR/LIFR CONDITIONS CONTINUE. A SLOW MOVING COLD FRONT WILL PASS
THROUGH THE REGION TODAY INTO EARLY TONIGHT. LIFT FROM THE FRONT
WILL LIKELY RAISE THE CEILINGS AND VISIBILITY TODAY AND MAY ALSO
RESULT IN SOME LIGHT SNOW OR FLURRIES. CONDITIONS COULD IMPROVE INTO
THE MVFR RANGE. SURFACE WINDS WILL CONTINUE LIGHT AND VARIABLE. 94
&&
.PREV DISCUSSION... /ISSUED 300 AM PST SUN DEC 11 2011/
SHORT TERM...TODAY THROUGH MONDAY NIGHT...A WEAK WAVE IS CENTERED
OVER EASTERN OREGON AT THE MOMENT. THIS WAVE WILL BE OUT OF THE AREA
BY MID MORNING. THIS WAVE IS CREATING JUST ENOUGH LIFT TO IMPROVE
VISIBILITIES SLIGHTLY WITHIN THE FOGGY AREAS UNDER THE COLUMBIA
BASIN INVERSION. IT COULD ALSO CAUSE A FEW SNOW FLURRIES HERE AND
THERE EARLY THIS MORNING IN THE SAME AREAS THAT HAVE LOW CLOUDS AND
FOG IN THE BASIN.
AN UPPER LEVEL TROUGH MOVING THROUGH NORTHERN BRITISH COLUMBIA AND
THE EASTERN PACIFIC CONTINUES TO APPROACH THE PACIFIC NORTHWEST
EARLY THIS MORNING. THIS TROUGH WILL CONTINUE TO DEEPEN AND SHEAR AS
THE BULK OF IT`S ENERGY WILL DIVE TO SOUTHERN CALIFORNIA DURING THE
NEXT 24 HOURS. THIS TROUGH WILL PUSH COOLER AIR ALOFT INTO THE
REGION ALLOWING FOR THE INVERSIONS OVER THE COLUMBIA BASIN TO WEAKEN
TODAY. AT THE SAME TIME, THOUGH, WINDS MAY BE TOO LIGHT TO MIX OUT
THE STAGNANT AIR MASS IN THE COLUMBIA BASIN. AS SUCH DO EXPECT THE
FOG AND LOW CLOUDS TO DISSIPATE, THOUGH CLOUD BASES MAY RISE AND
VISIBILITIES MAY IMPROVE WHERE THEY REMAIN LOW EARLY THIS MORNING.
THERE COULD EVEN BE A FEW BREAKS IN THE LOWER CLOUD COVER OVER THE
BASIN. PRECIP FROM THIS SYSTEM WILL LIMITED TO A FEW SNOW SHOWERS
OVER SOME OF THE MOUNTAINS AT TIMES TODAY AND TONIGHT. ALSO MAY SEE
A FEW SNOW FLURRIES WITHIN THE AREAS OF LOW CLOUDS AND FOG TODAY.
NORTH FLOW TONIGHT SHOULD PUSH SOME LOW CLOUDS AND FOG INTO PORTIONS
OF CENTRAL OREGON NEAR THE CASCADES. ALSO COULD SEE A FEW SNOW
SHOWERS OR FLURRIES IN THIS SAME AREA. TEMPERATURES TODAY WILL COOL
AT LOCATIONS ABOVE 3000 FEET VERSUS SATURDAY. TEMPERATURES BELOW
3000 FEET WILL BE SIMILAR OR SLIGHTLY HIGHER THAN YESTERDAY, THOUGH
HOW THEY END UP WILL BE DETERMINED BY HOW MUCH INVERSION BREAK UP
OCCURS. 90
LONG TERM...TUESDAY THROUGH SATURDAY...RIDGE AXIS MOVES THROUGH THE
AREA TUESDAY...AS AN UPPER LEVEL LOW PRESSURE MOVES THROUGH BRITISH
COLUMBIA TUESDAY NIGHT WITH NORTHERLY FLOW WEDNESDAY. A LOW PRESSURE
SYSTEM IS EXPECTED TO MOVE NEAR THE OREGON COAST WEDNESDAY NIGHT AND
SPREAD ACROSS THE REGION THURSDAY WITH A MIX OF RAIN AND SNOW. SOME
SNOW COULD LINGER OVER THE MOUNTAINS WITH NORTHERLY FLOW THURSDAY
NIGHT. HIGH PRESSURE BUILDS OVER THE AREA FRIDAY WITH ANOTHER SYSTEM
TO MOVE THROUGH SATURDAY. 93
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 27 21 32 20 / 10 20 0 0
ALW 29 24 33 23 / 10 20 0 0
PSC 30 20 34 17 / 10 20 0 0
YKM 29 16 32 15 / 10 10 0 0
HRI 30 20 34 16 / 10 20 0 0
ELN 31 18 32 16 / 10 10 0 0
RDM 42 13 39 9 / 10 10 0 0
LGD 37 20 33 16 / 10 20 0 0
GCD 39 20 37 17 / 10 10 0 0
DLS 38 26 39 22 / 10 10 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST MONDAY
ORZ041-042-044-050-505-507-508.
FREEZING FOG ADVISORY UNTIL 1 PM PST THIS AFTERNOON ORZ507-508.
FREEZING FOG ADVISORY UNTIL 1 PM PST THIS AFTERNOON BELOW 2500
FEET FOR THE ORZ042.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST MONDAY WAZ024-026>029-521.
FREEZING FOG ADVISORY UNTIL 1 PM PST THIS AFTERNOON WAZ028-029.
FREEZING FOG ADVISORY UNTIL 1 PM PST THIS AFTERNOON BELOW 2500
FEET FOR THE WAZ521.
&&
THREAT INDEX
TODAY : GREEN
MONDAY : GREEN
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
83/93/94
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1158 AM CST SUN DEC 11 2011
.DISCUSSION...SEE AVIATION SECTION FOR 18Z TAF ANALYSIS.
&&
.AVIATION...AND DOWN WE GO. ABOUT THE ONLY QUESTION FOR THE NEXT
24 HOURS IS HOW FAR INTO THE IFR CEILING CATEGORY WE DIP. GUT
FEELING SAYS WE`LL BE FLIRTING WITH THE IFR/LIFR RIGHT THROUGH THE
PERIOD. MAIN REASON IS THE SLOW EROSION OF THE COLDEST AIR...WHICH
WILL ALLOW TEMPERATURES AND DEWPOINTS TO REMAIN STEADY OR EVEN
RISE VERY SLOWLY OVERNIGHT...ASSUMING THE LAND DRAINAGE FLOW
CONTINUES TO KEEP TEMPERATURES MAINLY IN THE 50S AT KHRL/KMFE AND
AROUND 60 AT KBRO. WITH HUMIDITY NEAR 100 PERCENT IT IS REALISTIC
TO SEE CURRENT 500-600 FOOT CEILINGS LOCK IN AND EVEN DROP A
SHADE. WITH THE LOW CEILINGS SHOULD COME SOME FUZZY FOG AND MORE
DRIZZLE...BUT DON`T SEE VISIBILITY REACTING TOO STRONGLY WITH NEAR
STEADY (VERSUS RISING) TEMPERATURES. FOR NOW HAVE HELD AT MVFR LEVELS.
AS FOR MONDAY...WILL BE A SLOW GO TO BREAK OUT WITH INLAND COLD
AIR HANGING ON AND FLOWING TOWARD THE COAST. UNSURE WHEN EASTERLY
WIND WILL RETURN TO KBRO SO WENT VARIABLE TO THE END OF THE
PERIOD. WINDS SHOULD STAY FROM THE WEST/NORTHWEST TO VARIABLE AT
KHRL/KMFE.
AS FOR WIND SHEAR...EXPECT MODERATE LEVELS TO SET UP GIVEN THE
LIGHT SURFACE BREEZE FROM 290-330 WITH A QUICK TURN TO 090 AT NEAR
20 TO 25 KNOTS AT 1000 TO 2000 FEET THROUGH THE PERIOD. WEAKENING
LOW LEVEL WIND FIELDS SHOULD KEEP THESE SPEEDS...OR PERHAPS
LOWER...PRECLUDING NEED TO MENTION IN THIS SET OF TAFS.
STILL...DIRECTIONAL CHANGE WORTH A MENTION./52-BSG/
&&
.PREV DISCUSSION... /ISSUED 1102 AM CST SUN DEC 11 2011/
DISCUSSION...SEE BELOW FOR SHORT TERM AND MARINE ADJUSTMENTS THIS MORNING.
SHORT TERM /THIS AFTERNOON THROUGH MONDAY/...WITH THE WEAKENING
COASTAL TROUGH HAS COME A CONTINUED BACKING OF THE SURFACE WIND TO
THE NORTHWEST WHICH IS EDGING TOWARD THE LAGUNA SHORELINE. THIS IS
NOT TOO SURPRISING GIVEN IMBALANCE OF TEMPERATURE BETWEEN LAND AND
SEA...40S TO UPPER 60S...AND DENSITY IMBALANCE ALLOWS THE SHALLOW
AIR TO ACT LIKE A `SIDE DOOR` COLD FRONT. THE THICK LOW CLOUDS AND
OCCASIONAL DRIZZLE WON`T LET ANY INSOLATION IN...AND GIVEN THAT
WE`RE AT THE NADIR OF SUN ANGLE CONFIDENCE IS HIGH THAT
TEMPERATURES WON`T MOVE MUCH FROM THEIR CURRENT LEVELS.
WITH ALL THIS IN MIND...HAVE PULLED DOWN READINGS BY SOME 5 TO 8
DEGREES INLAND AS HIGHS WILL ONLY REACH 50 TO 55 FROM THE
HIDALGO/CAMERON LINE THROUGH WESTERN KENEDY COUNTY WEST TO THE RIO
GRANDE PLAINS. CLOSER TO THE COAST THINGS A BIT TRICKIER. HAVE
SEEN THE `FRONT` SHIFT RIGHT TO LAGUNA MADRE AND BAYVIEW HAS
DROPPED FROM 65 TO 58 LAST HOUR. WILL CONTINUE TO MONITOR AND
TWEAK TEMPERATURES FROM IN EASTERN CAMERON AS NEEDED.
AS FOR WINDS...DUMPED THE MODEL WINDS FOR RUC VALUES THROUGH THIS
AFTERNOON AND POPULATED THE MORE REALISTIC NAM 12 WINDS OVERNIGHT
WHICH SHOW THE NORTHWEST/WEST LAND TO SEA FLOW CONTINUING RIGHT
INTO MIDDAY MONDAY. THAT FLOW WILL ALSO LOCK DOWN A COOL-ISH DAY
ALONG/WEST OF HIGHWAY 281...WHILE ENOUGH EAST TO SOUTHEAST FLOW
SHOULD ARRIVE FARTHER EAST TO BEGIN ERODING THE DAMMED AIRMASS.
HAVE ADJUSTED TEMPERATURES WEST OF HIGHWAY 281 ACCORDINGLY AS WELL
AND WILL TWEAK MORE EARLY THIS AFTERNOON.
AS FOR WEATHER...CURRENT FORECAST OF DRIZZLE/PATCHY LIGHT RAIN
WORKING OUT NICELY. WILL TAKE A CLOSER LOOK FOR FOG POTENTIAL
OVERNIGHT AS SOME AREAS MAY HAVE TEMPERATURE RISES AS THE AIR MASS
SLOWLY MODIFIES. MORE ON THAT POTENTIAL IN A FEW HOURS.
FINALLY...SURF REPORTED RIGHT AT HEAD HEIGHT THIS
MORNING...VERIFYING OUR ADVISORY CONDITIONS. EXPECT THESE
CONDITIONS TO IMPROVE OVER THE NEXT FEW HOURS AND MAY CANCEL THIS
ADVISORY BY 2 PM. STILL DECENT FOR SURFERS...BUT LOUSY WEATHER
KEEPING NON-SURFERS OFF THE BEACH THIS WEEKEND.
MARINE...HAVE LET ADVISORY EXPIRE IN LAGUNA AS WINDS HAVE DROPPED
BELOW 10 KNOTS. IN FACT...WEST SIDE OF LAGUNA (PORT ISABEL CMAN)
HAS SHIFTED TO WEST AS WELL. WORDED AS NORTH 10 TO 15 KNOTS
OVERALL...BUT WENT VARIABLE OVERNIGHT. FOR THE GULF...SEAS AND
SWELL JUST BEGINNING TO DROP AS WINDS FALLING BELOW 20 KNOT
LEVELS...BARELY. ADVISORY WILL CONTINUE THROUGH AFTERNOON.
CLIMATE...PRELIMINARY RAINFALL TOTALS ARE AVAILABLE RIGHT ON
FRONT PAGE ON TOP NEWS AND A GRAPHIC...HTTP://WEATHER.GOV/RGV. THE
BIG STORY IS OUT WEST WHERE 2 TO NEARLY 3 INCHES FELL ALONG THE
RIVER FROM NEAR MCALLEN TO SOUTHWEST STARR COUNTY. SOME OF THESE
AREAS HAD NEARLY 50 PERCENT OF THEIR PREVIOUS 14 MONTHS (SINCE
OCTOBER 1 2010) RAINFALL...WHICH WAS BELOW 5 INCHES IN TOTAL.
NOT A DROUGHT KILLER...BUT CERTAINLY A RELIEVER. MORE IN THE
AFTERNOON DISCUSSION.
SHORT TERM UPDATES...52/BSG
PREV DISCUSSION... /ISSUED 534 AM CST SUN DEC 11 2011/
DISCUSSION...SEE THE AVIATION SEGMENT BELOW FOR THE DISCUSSION OF
THE 12Z TAF ISSUANCE.
AVIATION...SATELLITE AND RADAR IMAGES AS WELL AS SURFACE
OBSERVATIONS CONTINUE TO INDICATE LIGHT RAIN OR DRIZZLE WITH FOG
ACROSS PORTIONS OF THE RIO GRANDE VALLEY THIS MORNING. CEILINGS
WERE NEAR 400FT AT KMFE AND KT65 TO NEAR 7500FT KBKS. VISIBILITIES
WERE NEAR 3SM WITH DRIZZLE AND FOG AT KAPY TO NEAR 6SM WITH LIGHT
RAIN AND FOG KMFE. EXPECT MVFR TO IFR CONDITIONS TO CONTINUE TODAY
WITH LIGHT RAIN OR DRIZZLE WITH FOG CONTINUING TO DEVELOP AS A
COASTAL TROUGH ALONG THE LOWER TEXAS COAST CONTINUES TO ALLOW
MOISTURE TO POOL ACROSS THE CWA THIS MORNING THROUGH THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 345 AM CST SUN DEC 11 2011/
SHORT TERM /TODAY THROUGH MONDAY/...SATELLITE AND RADAR IMAGES
INDICATE LIGHT RAIN FALLING ACROSS SOUTHEAST PORTIONS OF THE CWA
EARLY THIS MORNING WITH AREAS OF DRIZZLE ACROSS THE REMAINDER OF
THE RIO GRANDE VALLEY. RAIN CHANCES SHOULD GRADUALLY DIMINISH
TODAY THROUGH TONIGHT AS LOW TO MID LEVEL MOISTURE ACROSS SOUTH TX
AND NORTHEAST MEXICO AS THE COASTAL TROUGH WEAKENS LATER TODAY
INTO THIS EVENING. THE SURFACE HIGH PRESSURE RIDGE ACROSS THE
EASTERN UNITED STATES EXTENDING INTO TX WILL WEAKEN ACROSS THE
STATE ALLOWING WINDS TO VEER TO THE EAST TONIGHT AND SOUTHEAST
MONDAY. WILL CONTINUE TO MENTION A SLIGHT CHANCE TO CHANCE OF RAIN
WITH OCCASIONAL DRIZZLE TONIGHT THROUGH MONDAY BEFORE THE
ISENTROPIC LIFTING ACROSS THE RIO GRANDE VALLEY DIMINISHES.
STRONG NORTHEAST WINDS AND SWELLS FROM THE NORTHEAST WILL CONTINUE
TO DRIVE HIGH SURF AND PROVIDE A HIGH RISK OF RIP CURRENTS ALONG THE
LOWER TEXAS TODAY. WILL GO AHEAD AND EXTEND HIGH SURF ADVISORY FOR
THE COASTAL SECTIONS OF THE CWA THROUGH THIS AFTERNOON. TIDES ARE
BEGINNING TO FALL AND THIS SHOULD ALLOW ANY MINOR TIDAL OVERFLOW
ALONG THE DUNES TO DIMINISH THIS MORNING EVEN THOUGH TIDES CONTINUE
TO RUN 1 FOOT ABOVE NORMAL AND NEAR 2 FEET ABOVE MEAN LOWER LOW
WATER.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...BY MONDAY NIGHT...THE
MIDLEVEL RIDGE WILL BE BUILDING NORTHWARD ACROSS THE WESTERN GULF.
THIS WILL PUSH THE SOUTHERN STREAM JET FURTHER NORTH...ALLOWING
THE JET INDUCED SFC COASTAL TROUGH TO DISSIPATE. TUESDAY AND
WEDNESDAY THE NEXT FRONTAL BOUNDARY WILL BEGIN TO FORM AND
APPROACH THE REGION FROM THE WEST. A SHORTWAVE TROUGH EJECTING
THROUGH THE CENTRAL PLAINS WILL NUDGE THE RIDGE JUST FAR ENOUGH
EAST TO ALLOW THE FRONT TO MOVE INTO THE REGION BEFORE STALLING.
CURRENT LONG TERM FORECAST HAS THE FRONT DISSIPATING LOCALLY
BEFORE RETREATING NORTHWARD...KEEPING THE ABOVE NORMAL
TEMPERATURES IN PLACE FROM TUESDAY THROUGH SATURDAY...WITH ONLY A
BRIEF DECREASE THURSDAY WITH THE FRONT IN THE VICINITY.
MARINE...
TODAY THROUGH MONDAY...SEAS WERE NEAR 10 FEET WITH EAST-NORTHEAST
WINDS NEAR 21 KNOTS AT BUOY020 EARLY THIS MORNING. WINDS WILL REMAIN
STRONG FROM THE EAST-NORTHEAST OFFSHORE THE LOWER TX COAST TODAY AND
WILL VEER TO THE EAST TONIGHT BEFORE THE PRESSURE GRADIENT ACROSS
THE LOWER TX COAST GRADUALLY WEAKENS TONIGHT INTO MONDAY. WINDS WILL
GRADUALLY DIMINISH LATE TONIGHT INTO MONDAY AS WINDS VEER TO THE
SOUTHEAST MONDAY. WILL GO AHEAD AND EXTEND THE SCA FOR THE OFFSHORE
WATERS THROUGH TONIGHT FOR SEAS IF NOT WINDS.
MONDAY NIGHT THROUGH THURSDAY...SOUTHEAST WINDS WILL DEVELOP
DURING THE EXTENDED FORECAST AS THE COASTAL TROUGH DISSIPATES.
WIND FLOW WILL RUN BETWEEN SFC HIGH TO THE NE AND LOW PRESSURE
DEVELOPING ALONG THE NEXT APPROACHING COLD FRONT. WINDS WILL
APPROACH 20 KNOTS WEDNESDAY...AND WILL DECREASE THURSDAY AS THE
FRONT STALLS IN THE VICINITY. SEAS DURING THE EXTENDED WILL RUN 3
TO 4 FEET TUESDAY...RISING TO 5 TO 7 FEET WEDNESDAY WITH THE
STRONGER WINDS.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH SURF ADVISORY UNTIL 6 PM CST THIS EVENING FOR TXZ251-256-
257.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WWW.WEATHER.GOV/BROWNSVILLE
52/51
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1102 AM CST SUN DEC 11 2011
.DISCUSSION...SEE BELOW FOR SHORT TERM AND MARINE ADJUSTMENTS THIS MORNING.
&&
.SHORT TERM /THIS AFTERNOON THROUGH MONDAY/...WITH THE WEAKENING
COASTAL TROUGH HAS COME A CONTINUED BACKING OF THE SURFACE WIND TO
THE NORTHWEST WHICH IS EDGING TOWARD THE LAGUNA SHORELINE. THIS IS
NOT TOO SURPRISING GIVEN IMBALANCE OF TEMPERATURE BETWEEN LAND AND
SEA...40S TO UPPER 60S...AND DENSITY IMBALANCE ALLOWS THE SHALLOW
AIR TO ACT LIKE A `SIDE DOOR` COLD FRONT. THE THICK LOW CLOUDS AND
OCCASIONAL DRIZZLE WON`T LET ANY INSOLATION IN...AND GIVEN THAT
WE`RE AT THE NADIR OF SUN ANGLE CONFIDENCE IS HIGH THAT
TEMPERATURES WON`T MOVE MUCH FROM THEIR CURRENT LEVELS.
WITH ALL THIS IN MIND...HAVE PULLED DOWN READINGS BY SOME 5 TO 8
DEGREES INLAND AS HIGHS WILL ONLY REACH 50 TO 55 FROM THE
HIDALGO/CAMERON LINE THROUGH WESTERN KENEDY COUNTY WEST TO THE RIO
GRANDE PLAINS. CLOSER TO THE COAST THINGS A BIT TRICKIER. HAVE
SEEN THE `FRONT` SHIFT RIGHT TO LAGUNA MADRE AND BAYVIEW HAS
DROPPED FROM 65 TO 58 LAST HOUR. WILL CONTINUE TO MONITOR AND
TWEAK TEMPERATURES FROM IN EASTERN CAMERON AS NEEDED.
AS FOR WINDS...DUMPED THE MODEL WINDS FOR RUC VALUES THROUGH THIS
AFTERNOON AND POPULATED THE MORE REALISTIC NAM 12 WINDS OVERNIGHT
WHICH SHOW THE NORTHWEST/WEST LAND TO SEA FLOW CONTINUING RIGHT
INTO MIDDAY MONDAY. THAT FLOW WILL ALSO LOCK DOWN A COOL-ISH DAY
ALONG/WEST OF HIGHWAY 281...WHILE ENOUGH EAST TO SOUTHEAST FLOW
SHOULD ARRIVE FARTHER EAST TO BEGIN ERODING THE DAMMED AIRMASS.
HAVE ADJUSTED TEMPERATURES WEST OF HIGHWAY 281 ACCORDINGLY AS WELL
AND WILL TWEAK MORE EARLY THIS AFTERNOON.
AS FOR WEATHER...CURRENT FORECAST OF DRIZZLE/PATCHY LIGHT RAIN
WORKING OUT NICELY. WILL TAKE A CLOSER LOOK FOR FOG POTENTIAL
OVERNIGHT AS SOME AREAS MAY HAVE TEMPERATURE RISES AS THE AIR MASS
SLOWLY MODIFIES. MORE ON THAT POTENTIAL IN A FEW HOURS.
FINALLY...SURF REPORTED RIGHT AT HEAD HEIGHT THIS
MORNING...VERIFYING OUR ADVISORY CONDITIONS. EXPECT THESE
CONDITIONS TO IMPROVE OVER THE NEXT FEW HOURS AND MAY CANCEL THIS
ADVISORY BY 2 PM. STILL DECENT FOR SURFERS...BUT LOUSY WEATHER
KEEPING NON-SURFERS OFF THE BEACH THIS WEEKEND.
.MARINE...HAVE LET ADVISORY EXPIRE IN LAGUNA AS WINDS HAVE DROPPED
BELOW 10 KNOTS. IN FACT...WEST SIDE OF LAGUNA (PORT ISABEL CMAN)
HAS SHIFTED TO WEST AS WELL. WORDED AS NORTH 10 TO 15 KNOTS
OVERALL...BUT WENT VARIABLE OVERNIGHT. FOR THE GULF...SEAS AND
SWELL JUST BEGINNING TO DROP AS WINDS FALLING BELOW 20 KNOT
LEVELS...BARELY. ADVISORY WILL CONTINUE THROUGH AFTERNOON.
&&
.CLIMATE...PRELIMINARY RAINFALL TOTALS ARE AVAILABLE RIGHT ON
FRONT PAGE ON TOP NEWS AND A GRAPHIC...HTTP://WEATHER.GOV/RGV. THE
BIG STORY IS OUT WEST WHERE 2 TO NEARLY 3 INCHES FELL ALONG THE
RIVER FROM NEAR MCALLEN TO SOUTHWEST STARR COUNTY. SOME OF THESE
AREAS HAD NEARLY 50 PERCENT OF THEIR PREVIOUS 14 MONTHS (SINCE
OCTOBER 1 2010) RAINFALL...WHICH WAS BELOW 5 INCHES IN TOTAL.
NOT A DROUGHT KILLER...BUT CERTAINLY A RELIEVER. MORE IN THE
AFTERNOON DISCUSSION.
SHORT TERM UPDATES...52/BSG
&&
.PREV DISCUSSION... /ISSUED 534 AM CST SUN DEC 11 2011/
DISCUSSION...SEE THE AVIATION SEGMENT BELOW FOR THE DISCUSSION OF
THE 12Z TAF ISSUANCE.
AVIATION...SATELLITE AND RADAR IMAGES AS WELL AS SURFACE
OBSERVATIONS CONTINUE TO INDICATE LIGHT RAIN OR DRIZZLE WITH FOG
ACROSS PORTIONS OF THE RIO GRANDE VALLEY THIS MORNING. CEILINGS
WERE NEAR 400FT AT KMFE AND KT65 TO NEAR 7500FT KBKS. VISIBILITIES
WERE NEAR 3SM WITH DRIZZLE AND FOG AT KAPY TO NEAR 6SM WITH LIGHT
RAIN AND FOG KMFE. EXPECT MVFR TO IFR CONDITIONS TO CONTINUE TODAY
WITH LIGHT RAIN OR DRIZZLE WITH FOG CONTINUING TO DEVELOP AS A
COASTAL TROUGH ALONG THE LOWER TEXAS COAST CONTINUES TO ALLOW
MOISTURE TO POOL ACROSS THE CWA THIS MORNING THROUGH THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 345 AM CST SUN DEC 11 2011/
SHORT TERM /TODAY THROUGH MONDAY/...SATELLITE AND RADAR IMAGES
INDICATE LIGHT RAIN FALLING ACROSS SOUTHEAST PORTIONS OF THE CWA
EARLY THIS MORNING WITH AREAS OF DRIZZLE ACROSS THE REMAINDER OF
THE RIO GRANDE VALLEY. RAIN CHANCES SHOULD GRADUALLY DIMINISH
TODAY THROUGH TONIGHT AS LOW TO MID LEVEL MOISTURE ACROSS SOUTH TX
AND NORTHEAST MEXICO AS THE COASTAL TROUGH WEAKENS LATER TODAY
INTO THIS EVENING. THE SURFACE HIGH PRESSURE RIDGE ACROSS THE
EASTERN UNITED STATES EXTENDING INTO TX WILL WEAKEN ACROSS THE
STATE ALLOWING WINDS TO VEER TO THE EAST TONIGHT AND SOUTHEAST
MONDAY. WILL CONTINUE TO MENTION A SLIGHT CHANCE TO CHANCE OF RAIN
WITH OCCASIONAL DRIZZLE TONIGHT THROUGH MONDAY BEFORE THE
ISENTROPIC LIFTING ACROSS THE RIO GRANDE VALLEY DIMINISHES.
STRONG NORTHEAST WINDS AND SWELLS FROM THE NORTHEAST WILL CONTINUE
TO DRIVE HIGH SURF AND PROVIDE A HIGH RISK OF RIP CURRENTS ALONG THE
LOWER TEXAS TODAY. WILL GO AHEAD AND EXTEND HIGH SURF ADVISORY FOR
THE COASTAL SECTIONS OF THE CWA THROUGH THIS AFTERNOON. TIDES ARE
BEGINNING TO FALL AND THIS SHOULD ALLOW ANY MINOR TIDAL OVERFLOW
ALONG THE DUNES TO DIMINISH THIS MORNING EVEN THOUGH TIDES CONTINUE
TO RUN 1 FOOT ABOVE NORMAL AND NEAR 2 FEET ABOVE MEAN LOWER LOW
WATER.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...BY MONDAY NIGHT...THE
MIDLEVEL RIDGE WILL BE BUILDING NORTHWARD ACROSS THE WESTERN GULF.
THIS WILL PUSH THE SOUTHERN STREAM JET FURTHER NORTH...ALLOWING
THE JET INDUCED SFC COASTAL TROUGH TO DISSIPATE. TUESDAY AND
WEDNESDAY THE NEXT FRONTAL BOUNDARY WILL BEGIN TO FORM AND
APPROACH THE REGION FROM THE WEST. A SHORTWAVE TROUGH EJECTING
THROUGH THE CENTRAL PLAINS WILL NUDGE THE RIDGE JUST FAR ENOUGH
EAST TO ALLOW THE FRONT TO MOVE INTO THE REGION BEFORE STALLING.
CURRENT LONG TERM FORECAST HAS THE FRONT DISSIPATING LOCALLY
BEFORE RETREATING NORTHWARD...KEEPING THE ABOVE NORMAL
TEMPERATURES IN PLACE FROM TUESDAY THROUGH SATURDAY...WITH ONLY A
BRIEF DECREASE THURSDAY WITH THE FRONT IN THE VICINITY.
MARINE...
TODAY THROUGH MONDAY...SEAS WERE NEAR 10 FEET WITH EAST-NORTHEAST
WINDS NEAR 21 KNOTS AT BUOY020 EARLY THIS MORNING. WINDS WILL REMAIN
STRONG FROM THE EAST-NORTHEAST OFFSHORE THE LOWER TX COAST TODAY AND
WILL VEER TO THE EAST TONIGHT BEFORE THE PRESSURE GRADIENT ACROSS
THE LOWER TX COAST GRADUALLY WEAKENS TONIGHT INTO MONDAY. WINDS WILL
GRADUALLY DIMINISH LATE TONIGHT INTO MONDAY AS WINDS VEER TO THE
SOUTHEAST MONDAY. WILL GO AHEAD AND EXTEND THE SCA FOR THE OFFSHORE
WATERS THROUGH TONIGHT FOR SEAS IF NOT WINDS.
MONDAY NIGHT THROUGH THURSDAY...SOUTHEAST WINDS WILL DEVELOP
DURING THE EXTENDED FORECAST AS THE COASTAL TROUGH DISSIPATES.
WIND FLOW WILL RUN BETWEEN SFC HIGH TO THE NE AND LOW PRESSURE
DEVELOPING ALONG THE NEXT APPROACHING COLD FRONT. WINDS WILL
APPROACH 20 KNOTS WEDNESDAY...AND WILL DECREASE THURSDAY AS THE
FRONT STALLS IN THE VICINITY. SEAS DURING THE EXTENDED WILL RUN 3
TO 4 FEET TUESDAY...RISING TO 5 TO 7 FEET WEDNESDAY WITH THE
STRONGER WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 66 63 73 68 / 40 20 30 10
BROWNSVILLE 63 60 72 66 / 40 20 30 10
HARLINGEN 61 56 73 65 / 40 20 30 10
MCALLEN 56 52 70 63 / 40 30 40 10
RIO GRANDE CITY 54 51 65 60 / 50 40 40 10
SOUTH PADRE ISLAND 67 65 72 69 / 40 20 20 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH SURF ADVISORY UNTIL 6 PM CST THIS EVENING FOR TXZ251-256-
257.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WWW.WEATHER.GOV/BROWNSVILLE
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1151 PM CST SAT DEC 10 2011
.AVIATION...
LIFR CONDITIONS ARE EXPECTED TO DEVELOP AT KLBB EARLY SUNDAY MORNING...
WITH LITTLE IMPROVEMENT UNTIL MIDDAY WITH SLOWLY IMPROVING CEILING
AND VISIBILITIES. LIGHT PRECIPITATION EXPECTED TO PREDOMINATE...WITH
INITIAL TEMPERATURES VERY CLOSE TO FREEZING...THOUGH FAVORED THE
MOST RECENT TRENDS SLIGHTLY HIGHER THAN FREEZING. SHOWERS SHOULD
EXPAND INTO KCDS AS WELL BY 08Z TO 10Z SUNDAY MORNING WITH DROP OF
MVFR CIGS AT THAT TIME TOWARDS IFR LEVELS. THESE CONDITIONS SHOULD
THEN DOMINATE FOR MUCH OF SUNDAY. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 943 PM CST SAT DEC 10 2011/
UPDATE...
VISIBILITIES WERE RAPIDLY DROPPING FROM WEST TO EAST ON THE CAPROCK
LATE THIS EVENING...IN SOME CASES TO NEAR ZERO. THIS TREND IS
EXPECTED TO CONTINUE SPREADING TO MOST AREAS ON THE CAPROCK BY
EARLY SUNDAY MORNING. LIGHT SOUTH TO SOUTHEASTERLY WINDS WILL
CONTINUE THROUGH THE NIGHT. THE REST OF THE FORECAST WITH
PRECIPITATION CHANCES IN THE MORNING STILL LOOK ON TRACK.
PREV DISCUSSION... /ISSUED 554 PM CST SAT DEC 10 2011/
AVIATION...
LOW CLOUD DECK REMAINS FAIRLY SOLID BOTH AT KCDS AND KLBB TO START
OUT THE NEW TAF PERIOD...IN SPITE OF BULK OF SOLUTIONS FAVORING AN
AFTERNOON BREAK. WE ARE FOLLOWING CLOSE TO THE LATEST RUC MODEL
RUN INDICATING MORE PERSISTENT LOW CLOUD LAYER AT BOTH SITES THIS
EVENING WITH CLOUD DECK LOWERING AROUND 06Z ALONG WITH AREAS OF
RAIN...FOG...AND DRIZZLE DEVELOPING. THE COLD TEMPERATURES MAY YET
BE AN ISSUE FOR KLBB AS LATEST RUC INDICATES SUB-FREEZING LAYER
NEAR THE SURFACE AS THE LIGHT PRECIPITATION DEVELOPS AND ONLY A
VERY SHALLOW WARM TONGUE ABOVE. SO...WE WILL BE STUDYING THIS
CLOSER THIS EVENING FOR A POSSIBLE UPDATE AS...HOPEFULLY...OUR
SOLUTIONS BECOME MORE USABLE. WE EXPECT TO REMAIN AT IFR OR LIFR
LEVELS FROM LATER TONIGHT INTO THE DAY SUNDAY WITH GRADUAL
IMPROVEMENT PERHAPS LATER SUNDAY THAT WE ALSO WILL ATTEMPT TO SHOW
WITH THE NEXT TAF ISSUANCE AT 06Z. RMCQUEEN
PREV DISCUSSION... /ISSUED 235 PM CST SAT DEC 10 2011/
SHORT TERM...
LOW CLOUDS HAVE BEEN HARD PRESSED TO SCATTERED OUT TODAY AND THIS
HAS KEPT TEMPERATURES COOL. A FEW BREAKS HAVE DEVELOPED ACROSS THE
NORTHWEST ZONES...WITH SOME THINNING ACROSS THE EASTERN
SECTIONS...AND THIS HAS ALLOWED THESE SPOTS TO WARM MODESTLY INTO
THE MID AND UPPER 30S TO AROUND 40 DEGREES. STILL COULD SEE MORE
BREAKS DEVELOP/EXPAND THIS AFTERNOON...BUT ANY THAT DO MATERIALIZE
WILL BE SHORT-LIVED. INSTEAD...INCREASING SOUTHERLY LOW-LEVEL FLOW
WILL DRAW DEEPER MOISTURE IN FROM THE SOUTH TONIGHT AS STRONG
MOISTURE ADVECTION ENSUES. THUS...EXPECT ANOTHER ROUND OF LOW-CLOUDS
AND FOG TO OVERSPREAD/REDEVELOP ACROSS THE REGION TONIGHT. THIS AS A
LOW AMPLITUDE SHORTWAVE TROUGH RAPIDLY APPROACHES FROM THE WEST
TONIGHT WITHIN QUASI-ZONAL MID-LEVEL FLOW. ALTHOUGH LOW-LEVEL
MOISTURE ADVECTION /GENERALLY AT AND BELOW 700 MB/ WILL BE
GOOD...OVERALL ISENTROPIC ACCENT AND PROGGED OMEGA FIELDS ARE WEAK
TONIGHT THROUGH SUNDAY. STILL...MOST NWP DOES CONTINUE TO INDICATE
LIGHT QPF DEVELOPING ACROSS THE SOUTHERN ZONES AFTER 06Z AND THEN
EXPANDING NORTH AND NORTHEAST THROUGH SUNDAY. ALL INDICATIONS ARE
THAT THIS PRECIPITATION WILL BE IN THE FORM OF DRIZZLE AND/OR VERY
LIGHT RAIN. TRICKIEST PART OF THE FORECAST REVOLVES AROUND
TEMPERATURES...WHICH WILL LIKELY RESIDE AT OR JUST BELOW THE
FREEZING MARK ON THE NORTHERN FRINGE OF THE ADVANCING
MOISTURE...THOUGH TEMPERATURES SHOULD GRADUALLY WARM AS DEEPER
MOISTURE ADVANCES NORTH LATE TONIGHT AND SUNDAY MORNING.
THUS...BIGGEST CONCERN WILL BE POTENTIAL FOR SOME FREEZING DRIZZLE
AND/OR VERY LIGHT FREEZING RAIN LATE TONIGHT AND EARLY
SUNDAY...FAVORING THE NORTHWEST ZONES. COULD SEE LIGHT FROZEN
PRECIPITATION INITIALLY ALONG AND NORTH OF A DENVER CITY TO LUBBOCK
TO CHILDRESS LINE AFTER MIDNIGHT TONIGHT...WITH THE FREEZING LINE
SLOWLY LIFTING TO THE NORTH SUNDAY MORNING. STILL...IT APPEARS THE
BEST CHANCE OF LIGHT RAIN/DRIZZLE WILL OCCUR AS MOISTURE PROFILES
DEEPEN AND SFC TEMPERATURES CLIMB TO AT OR JUST ABOVE THE FREEZING
MARK. GIVEN THIS...THINK OVERALL IMPACTS WILL BE LOW...BUT IT WILL
HAVE TO BE WATCHED CLOSELY. WILL CONTINUE A MENTION OF FOG/FREEZING
FOG AND POSSIBLE LIGHT FREEZING PRECIPITATION IN THE HWO FOR TONIGHT
AND SUNDAY MORNING. OTHERWISE...PRECIPITATION AMOUNTS LOOK TO REMAIN
LIGHT /IN THE HUNDREDTHS RANGE/...THOUGH DID CONTINUE A SLIGHT CHANCE
TO LOW END CHANCE OF PRECIPITATION ACROSS MUCH OF THE CWA LATE
TONIGHT THROUGH SUNDAY AFTERNOON. IT APPEARS THE FA WILL LIKELY
REMAIN SOCKED IN ALL DAY SUNDAY...SO ALTHOUGH WAA WILL GIVE
TEMPERATURES A SLIGHT BOOST...ONLY EXPECT HIGHS SUNDAY TO TOP OUT IN
THE LOWER TO MIDDLE 40S.
LONG TERM...
SHALLOW LOW LEVEL MOISTURE TO REMAIN ACROSS THE FCST AREA AHEAD OF
THE NEXT UPPER LEVEL TROUGH THAT WILL MOVE OVER THE PLAINS STATES
WEDNESDAY. MOISTURE WILL DEEPEN AHEAD OF THE TROUGH. MODEST MAINLY
ISENTROPIC LIFT SUNDAY NIGHT AND MONDAY WILL MORE LIKELY RESULT IN
CONTINUATION OF STRATUS AND POTENTIAL FOR FOG RATHER THAN LIGHT
RAIN. BY MONDAY NIGHT LIFT ALOFT WILL INCREASE. OVERALL TIMING OF
THIS NEXT TROUGH APPEARS TO BE ABOUT SIX HOURS FASTER THAN
PREVIOUS RUNS WHICH WOULD FOCUS PRECIP CHANCES FROM LATE MONDAY
NIGHT INTO TUESDAY NIGHT AND HAVE ADJUSTED POPS GRIDS ACCORDINGLY
WITH PACIFIC FRONT LIKELY DRIVING LOW LEVEL MOISTURE EAST OF THE
FCST BY LATE WEDNESDAY AND UPPER LEVEL LIFT SHIFTING EWD AT THAT
TIME AS WELL. OVERALL THE PATTERN STILL DOES NOT FAVOR WIDESPREAD
PRECIP AND HAVE KEPT POPS IN THE 20S AND 30S.
PERIOD OF TRANQUIL WEATHER LATE WEEK BEFORE THE NEXT SYSTEM
APPROACHES FROM THE WEST. 12Z RUNS LOOKING A BIT MORE FAVORABLE
FOR PRECIP NEXT SATURDAY BUT A BIT TOO EARLY TO INTRODUCE POPS
ATTM.
TEMPS EARLY IN THE PERIOD WILL MODERATE AS COLD AIR GETS AT LEAST
PARTIALLY DISLODGED. LOOKING AT MILD LOW TEMPS TUESDAY AND
WEDNESDAY WITH LOW LEVEL MOISTURE AND CLOUD COVER BUT THOSE
FACTORS WILL ALSO LIMIT DIURNAL RANGE AND THUS HIGH TEMPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 23 42 31 52 35 / 20 10 10 10 20
TULIA 27 41 34 49 39 / 20 20 10 10 20
PLAINVIEW 28 41 36 49 40 / 20 20 10 10 20
LEVELLAND 29 42 37 49 40 / 20 30 10 10 20
LUBBOCK 31 42 38 49 41 / 20 30 10 10 20
DENVER CITY 31 42 37 49 41 / 30 20 10 10 20
BROWNFIELD 32 43 37 50 41 / 30 30 10 10 20
CHILDRESS 31 45 36 52 40 / 10 30 10 10 20
SPUR 33 44 37 51 42 / 20 30 10 10 20
ASPERMONT 34 46 40 51 43 / 20 30 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL NOON CST SUNDAY FOR THE FOLLOWING
ZONES: TXZ021>024-027>030-033>036-039>042.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS SPOKANE WA
332 PM PST Mon Dec 12 2011
.SYNOPSIS...High pressure will be over the Inland Northwest for
the rest of today and into tonight through Wednesday. Some clearing is
possible this afternoon, but expect more fog/stratus formation
tonight. A stronger and more organized Pacific storm system will
arrive Wednesday evening and Thursday with the possibility of more
substantial snow accumulations.
&&
.DISCUSSION...
Tonight through Wednesday: More fog and stratus to deal with. With the
departure of the low pressure trough, high pressure has been
sinking into the region from the north and funneling down the
north/south valleys especially the Okanogan valley. This process
has helped erode and keep back the stratus that has been banked up
across the southern section of the forecast area. This area has a
well defined line - stretching from Othello to Harrington to just
south of Spokane and Coeur d`Alene to the Silver Valley. This
evening the northerly pressure gradient will weaken as high
pressure settles over the region. This will shut off the winds and
allow the area of stratus and fog to expand northward. This is
seen well by the NAM, RUC and the HRR encompassing the Spokane/
Coeur d`Alene area and the Moses Lake/Ephrata area and heading to
the northern valleys overnight and into Tuesday morning. Mixing
and winds will be weak on Tuesday giving way to little break up
the low level cloud deck. This will make temperatures tricky
depending on how clear some areas will be and for how long.
Anticipate diurnal temperature change from Lewiston to Pullman and
Ritzville. The coolest spots will be in the sheltered northern
valleys like the Methow and near Priest Lake. For Tuesday and
Tuesday night, a weak weather disturbance will ride over the upper
level ridge and spread mid and high level clouds across the Inland
Northwest. Dynamics look weak with a dry air above the boundary
layer, giving way to a slight chance of snow for the higher
elevations into the north and the Idaho Panhandle. This may
disrupt the stratus deck temporarily, but high pressure will
return again on Wednesday for more stable and dry conditions. The
air stagnation advisory will remain in effect for the region.
/rfox.
Wednesday night and Thursday...A dramatic change to the stagnant
and benign weather conditions of late will occur on Wednesday
night and Thursday. Just about all of the available model guidance
brings a noticeably stronger system through the region than the
recent feeble impulses. The ECMWF model has been most consistent
with the character of this incoming storm over the past few
days...although the GFS/Canadian/UKMET and SREF guidance have also
tenuously climbed aboard in the last 24 hours.
At this time it appears a rather vigorous and fast moving short
wave will drop through the region from northwest to southeast. the
cyclonic diffluent base dynamic region will sweep through the
northern zones and sustain a steady strength or slightly weakening
surface low pressure tracking just north of the Canadian border
and dropping into Montana by late Thursday. The close approach of
this low will drag a warm front/cold front couplet through the
northern and eastern zones late Wednesday night and Thursday
morning. For a six to 9 hour period or so a moderate Pacific
moisture feed will fuel precipitation along this frontal couplet.
Air mass characteristics will support snow in just about all
locations overnight and Thursday morning...but snow-water ratios
will likely be rather low in the lowest elevations at Lewiston and
Wenatchee. Thus...confidence is increasing for a widespread snow
event Wednesday night and Thursday. The northerly track of the
offending surface low and the relatively fast transit of the
heaviest lift region argues strongly that this will be a
significant...but generally sub-warning criteria event...perhaps
2-4 inches in the higher plateaus of the Columbia Basin and
valleys north and west of the basin. The best chance of truly
heavy snow will probably be near the Canadian border over
Northeast Washington and North Idaho closer to the actual surface
low track...and in the Panhandle Mountains where post frontal
orographic ascent will augment synoptic accumulation potential. It
is too early to pin down this potential as of yet. In any
event...Thursday morning`s commute will probably be dicey over
much of Eastern Washington and North Idaho.
This system will likely provide some relief to the recent run of
stagnant air quality...and the next conference call with air
quality officials will occur Thursday morning and the disposition
of the current Air Stagnation Advisory will be further evaluated
based on how this system manifest itself.
By late Thursday this storm is moving out of the region with
lingering snow showers in the Panhandle Mountains and probably the
Camas Prairie...While a new shot of dry continental air will push
down the Okanogan Valley and begin a new low level air mass
exchange in the Columbia Basin.
Thursday night through Saturday...Reasonable model agreement
continues this period featuring a new upper level ridge forming
over the northwest. This will lead to generally dry and quiet
conditions with a possible return to increasingly stagnant
inversion conditions once again. Where models do differ...it is
with the strength of this ridge and the potential for weak
impulses to trigger a few mountain snow showers across the north
and maybe a stray flurry in some valley locations. Otherwise it
looks like an essentially dry and cool period...but with a better
potential for overnight and early morning fog since fresh snow
cover will provide a better moisture source and enhance
overnight radiational cooling potential better than the recent
stretch of quiet weather. /Fugazzi
For Saturday night through Monday...The EC brings a quick hitting
system across the Inland Northwest Saturday night in deep
northwesterly flow. This would likely only result in light
mountain snow before the model develops the ridge of high pressure
back over the Pacific Northwest. The GFS meanwhile brings a weak
stretching system across the Inland Northwest Sunday dampening the
ridge, which allows the jet stream to shift overhead, and
subsequently allow a series of storm systems to move into the
region early next week...more typical of December. However, given
the pattern of late, I trended pops below climo and more in line
with the EC. /Neuman
&&
.AVIATION...
00Z TAFs...A weak upper level ridge will continue over the region
through 00Z Wednesday with a surface high pressure becoming
established over the Idaho Panhandle tonight and remaining through
Tuesday. Visible satellite at 23Z indicates a large area of
stratus with bases 2.5Kft to 3.5 Kft MSL and tops around 4.0 Kft
over the eastern and southern Columbia Basin. This status field
was spreading north and west and will envelop the KGEG area TAF
sites by 01-02Z and probably the KMWH site by 03-04Z tonight. Once
this IFR and LIFR ceiling stratus field becomes
established...there are no significant disturbances that will
break it up in the next 24 hours...and the expected surface
gradient will tend to spread the area westward possibly impacting
the KEAT TAF site after 12Z-15Z Tuesday. /MJF
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 18 29 21 32 25 33 / 0 10 10 0 60 60
Coeur d`Alene 18 30 22 33 26 33 / 0 10 10 10 70 60
Pullman 23 33 23 36 27 35 / 0 10 10 10 50 60
Lewiston 22 35 25 38 29 40 / 0 10 10 10 30 50
Colville 20 30 20 32 22 34 / 0 10 10 10 70 60
Sandpoint 18 28 22 31 24 33 / 0 10 20 10 70 70
Kellogg 20 29 22 32 25 31 / 0 10 20 20 60 70
Moses Lake 16 30 15 33 21 36 / 0 10 0 10 40 20
Wenatchee 19 29 23 32 26 36 / 0 10 0 10 60 20
Omak 13 30 18 32 21 36 / 0 10 0 10 70 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Air Stagnation Advisory until Noon PST Thursday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
Lewiston Area-Northern Panhandle.
WA...Air Stagnation Advisory until Noon PST Thursday for East Slopes
Northern Cascades-Lower Garfield and Asotin Counties-Moses
Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan
Valley-Spokane Area-Upper Columbia Basin-Washington Palouse-
Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 PM CST SUN DEC 11 2011
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
250 PM CST SUN DEC 11 2011
AMPLE CHALLENGES TO THE FORECAST FOR THE NEXT FEW DAYS...WITH THE
FOCUS ON THE PCPN TYPE.
TONIGHT AND MONDAY NOT LOOKING AS CLEAR-CUT AS THE PAST FEW DAYS
SUGGESTED IT WOULD BE...WITH FREEZING DRIZZLE TO DRIZZLE AND BACK
OVER TO FREEZING DRIZZLE. PCPN WILL OCCUR FOR THE REGION...BUT WHAT
FALLS IS MORE HAZY NOW.
LATEST FOG/STRATUS SATELLITE IMAGERY INDICATES AN EXPANSIVE AREA OF
STRATUS MOVING NORTHEAST ACROSS THE PLAINS...SURGING ACROSS THE
LOCAL AREA. THIS WAS IN RESPONSE TO A WARM/MOIST PUSH OF LOW LEVEL
AIR RIDING ACROSS A SNOW PACK. DESPITE WINDS OF 10 KTS OR
GREATER...VSBYS WITH THE STRATUS ARE 2-4 MILES...BRINGING AN ASPECT
OF ADVECTION FOG TO THE FORECAST.
THE FAVORABLE LOW LEVEL MOISTURE TRANSPORT/WARM AIR ADVECTION NOSES
ACROSS THE FORECAST AREA TONIGHT...PERSISTING THROUGH MUCH OF
MONDAY. THIS IS ASSOCIATED WITH AN UPPER LEVEL SHORTWAVE THAT WILL
SPIN FROM THE CENTRAL PLAINS TO ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY BY 18Z MON. THE SATURATION IS ALL IN THE LOW LEVELS
THOUGH...AS EVIDENCED BY TIME/HEIGHT X-SECTIONS AND BUFKIT
SOUNDINGS. AS SUCH...THE DEPTH OF THE SATURATION AND TEMPS AT THE
TOP OF THE ANTICIPATED CLOUD LAYER WILL HAVE AN IMPACT ON THE PCPN
TYPE. PREVIOUS MODEL RUNS POINTED TO NO ICE IN THE CLOUD...THUS
LIQUID AND LIKELY DRIZZLE. HOWEVER...INDICATIONS NOW ARE THAT -10 TO
-12 C COULD BE REALIZED IN CLOUD TOPS...MAKING ICE MORE LIKELY AND
POTENTIALLY SNOW IF THE REST OF THE THERMAL PROFILE WOULD SUPPORT
IT. IN ADDITION...THE SATURATION COULD BECOME DEEP ENOUGH FOR A
PERIOD ON SAT WHERE RAIN WOULD BE MORE LIKELY RATHER THAN DRIZZLE.
ACCUMULATION WOULD STILL BE MINOR...AND BELIEVE DRIZZLE WILL BE THE
MORE PREDOMINANT LIQUID TYPE...SO WILL STAY WITH DRIZZLE FOR NOW.
ANOTHER QUESTION THAT HAS BECOME PROBLEMATIC ARE SFC TEMPS.
PREVIOUSLY FREEZING TEMPERATURES OVERNIGHT/MONDAY MORNING LOOKED
LIKE A SURE THING FOR THE ENTIRE FORECAST AREA. LATEST MODELS RUNS
BRING THIS INTO QUESTION. THE LOW LEVEL WARM AIR ADVECTION WILL NOT
ONLY GO INTO CLOUD/PCPN PRODUCTION LATE TONIGHT...BUT IT SHOULD ALSO
SERVE TO HELP STEADY...OR EVEN RISE...TEMPERATURES OVERNIGHT. IF
THIS OCCURS...WESTERN PARTS OF THE FORECAST AREA HAVE A
PRETTY GOOD CHANCE OF STAYING ABOVE FREEZING. LATEST RUC13 TEMPS AND
LAMP GUIDANCE SUPPORTS THIS...AND HAVE TAILORED TEMPS TONIGHT THIS
WAY. AS A RESULT...THE WESTERN 1/2 OF THE FORECAST AREA WILL LIKELY
MISS OUT ON ANY FREEZING DRIZZLE. FARTHER EAST THOUGH TEMPS HAVE A
MUCH BETTER CHANCE TO COOL TO FREEZING...AND THUS AN ICING THREAT
WHEN THE DRIZZLE MOVES IN. WILL GO WITH A FREEZING RAIN ADV FOR THE
COUNTIES IN THE EAST...ESPECIALLY IN THE I-94 CORRIDOR...FROM 09-15Z
MON.
THIS SCENARIO WILL HAVE TO BE MONITORED VERY CLOSELY TONIGHT...AS
THE AMOUNT OF WARMING AND ONSET OF THE DRIZZLE WILL OBVIOUSLY PLAY
KEY ROLES IN WHERE THE FREEZING DRIZZLE THREAT WILL BE HIGHEST.
AN UPPER LEVEL TROUGH WILL LIFT OUT OF THE DESERT
SOUTHWEST...BRINGING THE TROUGH AXIS ACROSS THE REGION ON WED. THIS
SYSTEM LOOKS LIKE IT COULD PACK A PRETTY GOOD PUNCH WITH GOOD QG
CONVERGENCE...SLOPING FRONTOGENETIC LIFT...AND THE ENERGY FROM THE
UPPER LEVEL SHORTWAVE. TIMING AND POSITIONING WILL PLAY AN IMPORTANT
ROLE AS WARM AIR WILL BE A FACTOR FOR PCPN TYPE.
UNFORTUNATELY...EACH MODEL HAS A DIFFERENT IDEA ON WHAT WILL
OCCUR...AND BRINGS THE FORECAST CONFIDENCE DOWN AS A RESULT. NAM IS
THE QUICKEST OF ALL...TAKING THE SFC LOW TO LAKE SUPERIOR BY 00Z
THU. THE GFS IS OVER SOUTHWEST IA...THE EC THE CENTRAL PLAINS...AND
THE GEM EASTERN IA. A LOT OF INCONSISTENCY WITHIN THE MODELS
TOO...EXCEPT FOR THE EC WHICH SHOWS A BIT BETTER RUN TO RUN
AGREEMENT. WILL LEAN ON THE EC AS A RESULT...BLENDING IT WITH THE
CONSENSUS SOLUTION.
BEFORE THE HEART OF THE SYSTEM MOVES IN WED
AFTERNOON/NIGHT...ANOTHER GOOD SURGE OF LOW LEVEL MOISTURE
TRANSPORT/WARM AIR ADVECTION TUE NIGHT/WED MORNING WILL LIKELY LEAD
TO A BROAD AREA OF PRECIPITATION SPREADING ACROSS PORTIONS OF THE
REGION. SATURATION LOOKS DEEP ENOUGH TO SUPPORT ICE IN THE
CLOUD...BUT WARMING IN THE NEAR SFC LAYER SUGGESTS MELTING AND THE
POTENTIAL FOR RAIN OR FREEZING RAIN. THE WARMING CONTINUES FOR THE
REST OF WED AS THE MAIN PART OF THE STORM MOVES IN...WITH RAIN THE
LIKELY PCPN TYPE AS A RESULT. LOOKS LIKE ANY SNOW BAND WITH THIS
STORM WILL HANG WELL WEST/NORTH. OVERALL...CONFIDENCE IS HIGH THAT
PRECIPITATION WILL OCCUR. WHEN ITS MOST LIKELY IS NOT. CONFIDENCE IS
ALSO RISING THAT IT WILL LIKELY BE RAIN FOR THE MAJORITY OF THE
EVENT.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
250 PM CST SUN DEC 11 2011
MODEL DIFFERENCES CONTINUE...LOWERING CONFIDENCE IN SOME OF THE
DETAILS. WHILE THE GFS HAS MOVED TO A NORTHWEST STORM TRACK ALA THE
ECMWF AND GEM...STILL LOTS OF TIMING VARIANCE ON HOW QUICKLY THE
SYSTEM WILL KICK NORTHEAST. THE GFS IS THE FAST SOLUTION...WITH THE
EC SLOWER AND THE GEM IN BETWEEN. THE EC WOULD LINGER PCPN LONGER
OVER THE FORECAST AREA...CONTINUING INTO THU. ALSO...WITH THE EC
STAYING THE FARTHEST WEST...ITS ALSO MUCH WARMER MAKING RAIN A
MORE LIKELY PCPN TYPE FOR A LONGER STRETCH OF TIME. PCPN TYPE WILL
BE A DIFFICULTY WITH THIS STORM. WILL CONTINUE TO LEAN ON THE
EC/CONSENSUS SOLUTION FOR NOW.
HIGH PRESSURE STARTS TO BUILD IN FROM THE WEST THU NIGHT...MOVING
OVERHEAD FOR SAT WHILE THE UPPER LEVEL FLOW TAKES ON A MORE ZONAL
SHAPE FOR THE WEEKEND. FRI/SAT SHOULD BE DRY WITH SEASONAL TEMPS.
&&
.AVIATION...THROUGH 18Z MONDAY
1156 AM CST SUN DEC 11 2011
MAIN CHALLENGES THIS TAF PERIOD ARE CEILINGS AND VISIBILITY
ASSOCIATED WITH STRATUS / FOG LAYER ADVECTING IN FROM CENTRAL AND
WESTERN IOWA...AND FREEZING DRIZZLE POTENTIAL DURING THE OVERNIGHT.
WITH WARM AIR AND STRONG MOISTURE RETURN OVER MELTING
SNOWPACK...LARGE AREA OF IFR AND LIFR CONDITIONS ONGOING AT 18Z
SUNDAY. CEILINGS AND VISIBILITIES WILL BE IMPACTED AT BOTH TAF
SITES...WHERE AT KRST CLOUD BASES WILL BE AROUND 500 FT
INITIALLY...AND DROPPING THROUGH THE EVENING TO AROUND 300 FT. AT
KLSE...CEILINGS SHOULD REMAIN AOA 1000 FT...BECOMING BROKEN AT 800
FT BY 00Z.
ATTENTION THEN TURNS TO FREEZING DRIZZLE POTENTIAL OVERNIGHT INTO
MONDAY MORNING. LATEST RUC AND NAM BUFKIT SOUNDINGS SUGGEST
SURFACE TEMPERATURES WILL REMAIN SLIGHTLY ABOVE FREEZING WITH A
DEEP SATURATED LAYER. WILL HAVE TO MONITOR CLOSELY BUT AT THIS
TIME...REMOVED FREEZING DRIZZLE FROM FORECAST. REGARDLESS...LIFR
CONDITIONS SHOULD PERSIST AT KRST AND IFR CONDITIONS AT KLSE
OVERNIGHT THROUGH MONDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST SUN DEC 11 2011
WI...FREEZING RAIN ADVISORY FROM 3 AM TO 9 AM CST MONDAY FOR WIZ017-
029-034-042>044-053>055-061.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION..... DAS/ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1157 AM CST SUN DEC 11 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
315 AM CST SUN DEC 11 2011
MAIN FORECAST CONCERN IS CENTERED ON FREEZING DRIZZLE AND ICING
POTENTIAL FROM LATE TONIGHT THROUGH MONDAY NIGHT AND THE NEED FOR A
FREEZING RAIN ADVISORY.
DATA ANALYSIS AT 08Z SHOWS MAINLY CLEAR SKIES ACROSS THE FORECAST
AREA. HOWEVER...SEVERAL PATCHES OF STRATUS ARE SEEN. THE FIRST
OVER NORTH CENTRAL WISCONSIN...WITH ITS EDGE IN TAYLOR COUNTY AND
THE SECOND ONE WHOSE LEADING EDGE IS MOVING INTO SOUTHWEST IOWA. PRESSURE
GRADIENT REMAINS RATHER TIGHT ACROSS THE AREA AND WITH THE WINDS
REMAINING UP...TEMPERATURES HAVEN/T FALLEN MUCH THROUGH THE
EVENING HOURS.
11.00Z MODELS ONCE AGAIN OFFER SIMILAR SOLUTIONS THROUGH THE
FORECAST PERIOD. IN THE NEAR TERM...QUIET WEATHER IS ON TAP FOR
TODAY AS WARM ADVECTION CONTINUES ON SOUTH TO SOUTHWEST LOW LEVEL
FLOW. 850MB TEMPERATURES IN THE +3 TO +4 CELSIUS RANGE WILL RESULT
IN SURFACE TEMPERATURES WELL INT THE 30S BY AFTERNOON...WITH SOME
LOWER 40S POSSIBLE IN THE WARMER VALLEY LOCATIONS. CAVEAT IS HOW
FAR NORTH THE SOUTHWEST IOWA STRATUS WILL GET. LATEST RUC SHOWS IT
REMAINING TO THE SOUTHWEST OF THE AREA...BUT SPEED DISTANCE TOOL
INDICATES IT MAY REACH NORTHEAST IOWA AROUND 14Z-15Z. THUS DID ADD
SOME EARLY MORNING CLOUDS TO THE GRIDS ACROSS THE SOUTHWEST...BUT
SHOULD MIX OUT LATER THIS MORNING. IF THESE PERSIST THEN
TEMPERATURES MAY BE COOLER THAN FORECAST.
BIGGEST WEATHER CONCERN IN THE NEAR TERM BEGINS LATE TONIGHT AS A
SHORTWAVE ROTATES INTO MINNESOTA. NICE FETCH OF LOW LEVEL MOISTURE
ADVECTS NORTHWARD ACROSS IOWA INTO WISCONSIN. MODELS HAVE BEEN VERY
CONSISTENT IN STRATUS DEVELOPMENT AS INDICATED IN THE 925MB-850MB
RELATIVE HUMIDITY PROGS. BUFKIT SOUNDINGS SHOW SATURATION
OCCURRING...MAINLY AFTER 06Z FROM THE SOUTHWEST. SATURATED COLUMN
DEEPENS TO 2 KM BY 12Z MONDAY WITH LIFT THROUGH THE SATURATED
COLUMN AHEAD OF THE SHORTWAVE WAVE. ONCE AGAIN...BUFKIT SOUNDINGS
FROM BOTH THE GFS AND NAM REMAIN CONSISTENT IN THE LACK OF ICE IN
THE CLOUD AND THUS PRECIPITATION WILL BE LIQUID FORM...AND GIVEN
LIFT/SATURATION DEPTH EEL FRIZZING DRIZZLE THE MOST LIKELY
OUTCOME. BIGGEST QUESTION THEN WILL BE SURFACE TEMPERATURES WITH
PERSISTENT LOW LEVEL WARM ADVECTION. MODELS CONTINUE TO ADVERTISE
SUB-FREEZING TEMPERATURES BY THE TIME THE PRECIPITATION BREAKS
OUT...GENERALLY IN THE 28 TO 31 DEGREE RANGE. AMOUNTS LOOK TO BE
LIGHT...BUT WILL LIKELY LEAD TO GLAZING WHICH WILL CONTINUE INTO
MONDAY MORNING BEFORE WARMING CHANGES PRECIPITATION TO JUST
DRIZZLE. LOOKS LIKE THE HIGHEST PROBABILITIES OF GLAZING WILL
OCCUR BETWEEN 09Z-18Z MONDAY. WITH STILL SOME QUESTION ON LOW
LEVEL TEMPERATURES AND WHEN SATURATION OCCURS AND AFTER
COLLABORATION WITH NEIGHBORING OFFICES WILL HOLD OFF ON ANY
ADVISORIES AT THIS TIME AND ALLOW DAY SHIFT TO EXAMINE THE LATEST
DATA.
SURFACE TEMPERATURES ONCE AGAIN LOOK TO COOL MONDAY EVENING...BUT
LIFT WILL BE EXITING THE AREA WITH THE WAVE. HOWEVER...LOW LEVELS
REMAIN SATURATED AND AGAIN COULD SEE THE DRIZZLE BECOME FREEZING
DRIZZLE OVERNIGHT. ALTHOUGH AT THIS TIME IT DOESN/T LOOK AS
WIDESPREAD...BUT WILL BEAR WATCHING FOR GLAZING POTENTIAL AGAIN.
QUIET WEATHER EXPECTED TUESDAY AS AREA IS IN BETWEEN SYSTEMS. BY
TUESDAY NIGHT THOUGH MOISTURE BEGINS TO SURGE NORTHWARD AGAIN AHEAD
OF THE LONG WAVE TROUGH OVER THE ROCKIES. THIS WILL SPREAD
PRECIPITATION BACK INTO THE AREA FROM THE SOUTH.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
315 AM CST SUN DEC 11 2011
CONFIDENCE NOT HIGH IN THIS TIME FRAME WITH REGARDS TO THE DETAILS
FOR WEDNESDAY AND THURSDAY AS MODELS HAVE REALLY STRUGGLED WITH THE
SYSTEM PULLING OUT OF THE PLAINS. 11.00Z GEM NOW THE FASTEST WITH
THE SYSTEM WITH THE SURFACE LOW IN CENTRAL WISCONSIN BY 00Z
THURSDAY...WHILE THE GFS PLACES IT IN IOWA AND ECMWF IS THE SLOWEST
HOLDING IT BACK ALONG THE KANSAS/NEBRASKA BORDER. HOWEVER...THE
TRACK IS FAIRLY CONSISTENT WITH THE LOW TRACKING ACROSS THE FORECAST
AREA. WITH THESE DIFFERENCES STILL DIFFICULT TO DISCERN PRECIPITATION
TYPES THIS FAR OUT...BUT LATEST TRENDS WOULD SUGGEST BEST CHANCES
FOR ANY ACCUMULATING SNOW TO BE OVER THE WESTERN AND NORTHERN AREAS.
WILL CONTINUE TO MENTION RAIN/SNOW POSSIBILITY. ONCE SYSTEM
EXITS..QUIET BUT COLD WEATHER EXPECTED THURSDAY NIGHT INTO SATURDAY.
&&
.AVIATION...THROUGH 18Z MONDAY
1156 AM CST SUN DEC 11 2011
MAIN CHALLENGES THIS TAF PERIOD ARE CEILINGS AND VISIBILITY
ASSOCIATED WITH STRATUS / FOG LAYER ADVECTING IN FROM CENTRAL AND
WESTERN IOWA...AND FREEZING DRIZZLE POTENTIAL DURING THE OVERNIGHT.
WITH WARM AIR AND STRONG MOISTURE RETURN OVER MELTING
SNOWPACK...LARGE AREA OF IFR AND LIFR CONDITIONS ONGOING AT 18Z
SUNDAY. CEILINGS AND VISIBILITIES WILL BE IMPACTED AT BOTH TAF
SITES...WHERE AT KRST CLOUD BASES WILL BE AROUND 500 FT
INITIALLY...AND DROPPING THROUGH THE EVENING TO AROUND 300 FT. AT
KLSE...CEILINGS SHOULD REMAIN AOA 1000 FT...BECOMING BROKEN AT 800
FT BY 00Z.
ATTENTION THEN TURNS TO FREEZING DRIZZLE POTENTIAL OVERNIGHT INTO
MONDAY MORNING. LATEST RUC AND NAM BUFKIT SOUNDINGS SUGGEST
SURFACE TEMPERATURES WILL REMAIN SLIGHTLY ABOVE FREEZING WITH A
DEEP SATURATED LAYER. WILL HAVE TO MONITOR CLOSELY BUT AT THIS
TIME...REMOVED FREEZING DRIZZLE FROM FORECAST. REGARDLESS...LIFR
CONDITIONS SHOULD PERSIST AT KRST AND IFR CONDITIONS AT KLSE
OVERNIGHT THROUGH MONDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CST SUN DEC 11 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM....RABERDING
AVIATION...DAS/ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
554 AM CST SUN DEC 11 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
315 AM CST SUN DEC 11 2011
MAIN FORECAST CONCERN IS CENTERED ON FREEZING DRIZZLE AND ICING
POTENTIAL FROM LATE TONIGHT THROUGH MONDAY NIGHT AND THE NEED FOR A
FREEZING RAIN ADVISORY.
DATA ANALYSIS AT 08Z SHOWS MAINLY CLEAR SKIES ACROSS THE FORECAST
AREA. HOWEVER...SEVERAL PATCHES OF STRATUS ARE SEEN. THE FIRST
OVER NORTH CENTRAL WISCONSIN...WITH ITS EDGE IN TAYLOR COUNTY AND
THE SECOND ONE WHOSE LEADING EDGE IS MOVING INTO SOUTHWEST IOWA. PRESSURE
GRADIENT REMAINS RATHER TIGHT ACROSS THE AREA AND WITH THE WINDS
REMAINING UP...TEMPERATURES HAVEN/T FALLEN MUCH THROUGH THE
EVENING HOURS.
11.00Z MODELS ONCE AGAIN OFFER SIMILAR SOLUTIONS THROUGH THE
FORECAST PERIOD. IN THE NEAR TERM...QUIET WEATHER IS ON TAP FOR
TODAY AS WARM ADVECTION CONTINUES ON SOUTH TO SOUTHWEST LOW LEVEL
FLOW. 850MB TEMPERATURES IN THE +3 TO +4 CELSIUS RANGE WILL RESULT
IN SURFACE TEMPERATURES WELL INT THE 30S BY AFTERNOON...WITH SOME
LOWER 40S POSSIBLE IN THE WARMER VALLEY LOCATIONS. CAVEAT IS HOW
FAR NORTH THE SOUTHWEST IOWA STRATUS WILL GET. LATEST RUC SHOWS IT
REMAINING TO THE SOUTHWEST OF THE AREA...BUT SPEED DISTANCE TOOL
INDICATES IT MAY REACH NORTHEAST IOWA AROUND 14Z-15Z. THUS DID ADD
SOME EARLY MORNING CLOUDS TO THE GRIDS ACROSS THE SOUTHWEST...BUT
SHOULD MIX OUT LATER THIS MORNING. IF THESE PERSIST THEN
TEMPERATURES MAY BE COOLER THAN FORECAST.
BIGGEST WEATHER CONCERN IN THE NEAR TERM BEGINS LATE TONIGHT AS A
SHORTWAVE ROTATES INTO MINNESOTA. NICE FETCH OF LOW LEVEL MOISTURE
ADVECTS NORTHWARD ACROSS IOWA INTO WISCONSIN. MODELS HAVE BEEN VERY
CONSISTENT IN STRATUS DEVELOPMENT AS INDICATED IN THE 925MB-850MB
RELATIVE HUMIDITY PROGS. BUFKIT SOUNDINGS SHOW SATURATION
OCCURRING...MAINLY AFTER 06Z FROM THE SOUTHWEST. SATURATED COLUMN
DEEPENS TO 2 KM BY 12Z MONDAY WITH LIFT THROUGH THE SATURATED
COLUMN AHEAD OF THE SHORTWAVE WAVE. ONCE AGAIN...BUFKIT SOUNDINGS
FROM BOTH THE GFS AND NAM REMAIN CONSISTENT IN THE LACK OF ICE IN
THE CLOUD AND THUS PRECIPITATION WILL BE LIQUID FORM...AND GIVEN
LIFT/SATURATION DEPTH EEL FRIZZING DRIZZLE THE MOST LIKELY
OUTCOME. BIGGEST QUESTION THEN WILL BE SURFACE TEMPERATURES WITH
PERSISTENT LOW LEVEL WARM ADVECTION. MODELS CONTINUE TO ADVERTISE
SUB-FREEZING TEMPERATURES BY THE TIME THE PRECIPITATION BREAKS
OUT...GENERALLY IN THE 28 TO 31 DEGREE RANGE. AMOUNTS LOOK TO BE
LIGHT...BUT WILL LIKELY LEAD TO GLAZING WHICH WILL CONTINUE INTO
MONDAY MORNING BEFORE WARMING CHANGES PRECIPITATION TO JUST
DRIZZLE. LOOKS LIKE THE HIGHEST PROBABILITIES OF GLAZING WILL
OCCUR BETWEEN 09Z-18Z MONDAY. WITH STILL SOME QUESTION ON LOW
LEVEL TEMPERATURES AND WHEN SATURATION OCCURS AND AFTER
COLLABORATION WITH NEIGHBORING OFFICES WILL HOLD OFF ON ANY
ADVISORIES AT THIS TIME AND ALLOW DAY SHIFT TO EXAMINE THE LATEST
DATA.
SURFACE TEMPERATURES ONCE AGAIN LOOK TO COOL MONDAY EVENING...BUT
LIFT WILL BE EXITING THE AREA WITH THE WAVE. HOWEVER...LOW LEVELS
REMAIN SATURATED AND AGAIN COULD SEE THE DRIZZLE BECOME FREEZING
DRIZZLE OVERNIGHT. ALTHOUGH AT THIS TIME IT DOESN/T LOOK AS
WIDESPREAD...BUT WILL BEAR WATCHING FOR GLAZING POTENTIAL AGAIN.
QUIET WEATHER EXPECTED TUESDAY AS AREA IS IN BETWEEN SYSTEMS. BY
TUESDAY NIGHT THOUGH MOISTURE BEGINS TO SURGE NORTHWARD AGAIN AHEAD
OF THE LONG WAVE TROUGH OVER THE ROCKIES. THIS WILL SPREAD
PRECIPITATION BACK INTO THE AREA FROM THE SOUTH.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
315 AM CST SUN DEC 11 2011
CONFIDENCE NOT HIGH IN THIS TIME FRAME WITH REGARDS TO THE DETAILS
FOR WEDNESDAY AND THURSDAY AS MODELS HAVE REALLY STRUGGLED WITH THE
SYSTEM PULLING OUT OF THE PLAINS. 11.00Z GEM NOW THE FASTEST WITH
THE SYSTEM WITH THE SURFACE LOW IN CENTRAL WISCONSIN BY 00Z
THURSDAY...WHILE THE GFS PLACES IT IN IOWA AND ECMWF IS THE SLOWEST
HOLDING IT BACK ALONG THE KANSAS/NEBRASKA BORDER. HOWEVER...THE
TRACK IS FAIRLY CONSISTENT WITH THE LOW TRACKING ACROSS THE FORECAST
AREA. WITH THESE DIFFERENCES STILL DIFFICULT TO DISCERN PRECIPITATION
TYPES THIS FAR OUT...BUT LATEST TRENDS WOULD SUGGEST BEST CHANCES
FOR ANY ACCUMULATING SNOW TO BE OVER THE WESTERN AND NORTHERN AREAS.
WILL CONTINUE TO MENTION RAIN/SNOW POSSIBILITY. ONCE SYSTEM
EXITS..QUIET BUT COLD WEATHER EXPECTED THURSDAY NIGHT INTO SATURDAY.
&&
.AVIATION...TODAY AND TONIGHT
554 AM CST SUN DEC 11 2011
IFR/MVFR STRATUS WILL MOVE FROM SOUTHWEST TO NORTHEAST ACROSS THE
TAF SITES FROM MID MORNING THROUGH THE AFTERNOON HOURS. LOOK FOR
CLOUD BASES TO LOWER TO 900 FT AT KRST BY 18Z AND 1500 FT AT KLSE
BY 20Z AS THE STRATUS MOVES THROUGH. LOW LEVEL MOISTURE WILL
CONTINUE TO INCREASE ACROSS THE AREA TODAY AS A FRONTAL BOUNDARY
APPROACHES FROM THE DAKOTAS/CENTRAL PLAINS. THERE COULD BE A FEW
BREAKS IN THE STRATUS DECK WITH INCREASING MIXING THIS AFTERNOON.
HOWEVER...WARMER AIR MOVING OVER THE SNOW PACK WILL HELP TO MELT
THE SNOW AND INCREASE BOUNDARY LAYER MOISTURE. THIS MAY ACT TO
REINFORCE THE STRATUS DECK AND MAINTAIN IT THROUGH THE AFTERNOON
HOURS. HAVE TRENDED TAFS TOWARD THIS SOLUTION WITH LATEST FORECAST
SOUNDINGS/OBSERVATIONS SUPPORTING THIS SCENARIO. AREAS OF BR WILL
ACCOMPANY THE STRATUS WITH VISIBILITIES FALLING INTO THE 4 TO 5SM
RANGE. LOOK FOR STRATUS TO SPREAD ACROSS THE ENTIRE AREA THIS
MORNING AS THE FRONT MOVES INTO THE AREA. LOOK FOR FREEZING
DRIZZLE TO DEVELOP AT KRST BY 06Z AND AT KLSE BY 08Z. CEILINGS
WILL LOWER LATE THIS EVENING INTO THE OVERNIGHT HOURS INTO THE 500
TO 900 FT RANGE. IFR CONDITIONS ARE EXPECTED LATE TONIGHT INTO
EARLY MONDAY MORNING...WITH FREEZING DRIZZLE PERSISTING. WILL HAVE
TO CLOSELY MONITOR THE NEXT SET OF MODEL RUNS FOR FOG POTENTIAL AT
THE TAF SITES. VISIBILITIES COULD FALL BELOW ONE HALF MILE AT THE
TAF SITES IF IT DEVELOPS. HAVE NOT INCLUDED VISIBILITIES THIS LOW
AT THIS TIME WITH FORECAST SOUNDING SHOWING SURFACE WINDS OUT OF
THE SOUTH TO SOUTHWEST AT 10 TO 15 KTS...PROMOTING MIXING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CST SUN DEC 11 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM....RABERDING
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CST SUN DEC 11 2011
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
315 AM CST SUN DEC 11 2011
MAIN FORECAST CONCERN IS CENTERED ON FREEZING DRIZZLE AND ICING
POTENTIAL FROM LATE TONIGHT THROUGH MONDAY NIGHT AND THE NEED FOR A
FREEZING RAIN ADVISORY.
DATA ANALYSIS AT 08Z SHOWS MAINLY CLEAR SKIES ACROSS THE FORECAST
AREA. HOWEVER...SEVERAL PATCHES OF STRATUS ARE SEEN. THE FIRST
OVER NORTH CENTRAL WISCONSIN...WITH ITS EDGE IN TAYLOR COUNTY AND
THE SECOND ONE WHOSE LEADING EDGE IS MOVING INTO SOUTHWEST IOWA. PRESSURE
GRADIENT REMAINS RATHER TIGHT ACROSS THE AREA AND WITH THE WINDS
REMAINING UP...TEMPERATURES HAVEN/T FALLEN MUCH THROUGH THE
EVENING HOURS.
11.00Z MODELS ONCE AGAIN OFFER SIMILAR SOLUTIONS THROUGH THE
FORECAST PERIOD. IN THE NEAR TERM...QUIET WEATHER IS ON TAP FOR
TODAY AS WARM ADVECTION CONTINUES ON SOUTH TO SOUTHWEST LOW LEVEL
FLOW. 850MB TEMPERATURES IN THE +3 TO +4 CELSIUS RANGE WILL RESULT
IN SURFACE TEMPERATURES WELL INT THE 30S BY AFTERNOON...WITH SOME
LOWER 40S POSSIBLE IN THE WARMER VALLEY LOCATIONS. CAVEAT IS HOW
FAR NORTH THE SOUTHWEST IOWA STRATUS WILL GET. LATEST RUC SHOWS IT
REMAINING TO THE SOUTHWEST OF THE AREA...BUT SPEED DISTANCE TOOL
INDICATES IT MAY REACH NORTHEAST IOWA AROUND 14Z-15Z. THUS DID ADD
SOME EARLY MORNING CLOUDS TO THE GRIDS ACROSS THE SOUTHWEST...BUT
SHOULD MIX OUT LATER THIS MORNING. IF THESE PERSIST THEN
TEMPERATURES MAY BE COOLER THAN FORECAST.
BIGGEST WEATHER CONCERN IN THE NEAR TERM BEGINS LATE TONIGHT AS A
SHORTWAVE ROTATES INTO MINNESOTA. NICE FETCH OF LOW LEVEL MOISTURE
ADVECTS NORTHWARD ACROSS IOWA INTO WISCONSIN. MODELS HAVE BEEN VERY
CONSISTENT IN STRATUS DEVELOPMENT AS INDICATED IN THE 925MB-850MB
RELATIVE HUMIDITY PROGS. BUFKIT SOUNDINGS SHOW SATURATION
OCCURRING...MAINLY AFTER 06Z FROM THE SOUTHWEST. SATURATED COLUMN
DEEPENS TO 2 KM BY 12Z MONDAY WITH LIFT THROUGH THE SATURATED
COLUMN AHEAD OF THE SHORTWAVE WAVE. ONCE AGAIN...BUFKIT SOUNDINGS
FROM BOTH THE GFS AND NAM REMAIN CONSISTENT IN THE LACK OF ICE IN
THE CLOUD AND THUS PRECIPITATION WILL BE LIQUID FORM...AND GIVEN
LIFT/SATURATION DEPTH EEL FRIZZING DRIZZLE THE MOST LIKELY
OUTCOME. BIGGEST QUESTION THEN WILL BE SURFACE TEMPERATURES WITH
PERSISTENT LOW LEVEL WARM ADVECTION. MODELS CONTINUE TO ADVERTISE
SUB-FREEZING TEMPERATURES BY THE TIME THE PRECIPITATION BREAKS
OUT...GENERALLY IN THE 28 TO 31 DEGREE RANGE. AMOUNTS LOOK TO BE
LIGHT...BUT WILL LIKELY LEAD TO GLAZING WHICH WILL CONTINUE INTO
MONDAY MORNING BEFORE WARMING CHANGES PRECIPITATION TO JUST
DRIZZLE. LOOKS LIKE THE HIGHEST PROBABILITIES OF GLAZING WILL
OCCUR BETWEEN 09Z-18Z MONDAY. WITH STILL SOME QUESTION ON LOW
LEVEL TEMPERATURES AND WHEN SATURATION OCCURS AND AFTER
COLLABORATION WITH NEIGHBORING OFFICES WILL HOLD OFF ON ANY
ADVISORIES AT THIS TIME AND ALLOW DAY SHIFT TO EXAMINE THE LATEST
DATA.
SURFACE TEMPERATURES ONCE AGAIN LOOK TO COOL MONDAY EVENING...BUT
LIFT WILL BE EXITING THE AREA WITH THE WAVE. HOWEVER...LOW LEVELS
REMAIN SATURATED AND AGAIN COULD SEE THE DRIZZLE BECOME FREEZING
DRIZZLE OVERNIGHT. ALTHOUGH AT THIS TIME IT DOESN/T LOOK AS
WIDESPREAD...BUT WILL BEAR WATCHING FOR GLAZING POTENTIAL AGAIN.
QUIET WEATHER EXPECTED TUESDAY AS AREA IS IN BETWEEN SYSTEMS. BY
TUESDAY NIGHT THOUGH MOISTURE BEGINS TO SURGE NORTHWARD AGAIN AHEAD
OF THE LONG WAVE TROUGH OVER THE ROCKIES. THIS WILL SPREAD
PRECIPITATION BACK INTO THE AREA FROM THE SOUTH.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
315 AM CST SUN DEC 11 2011
CONFIDENCE NOT HIGH IN THIS TIME FRAME WITH REGARDS TO THE DETAILS
FOR WEDNESDAY AND THURSDAY AS MODELS HAVE REALLY STRUGGLED WITH THE
SYSTEM PULLING OUT OF THE PLAINS. 11.00Z GEM NOW THE FASTEST WITH
THE SYSTEM WITH THE SURFACE LOW IN CENTRAL WISCONSIN BY 00Z
THURSDAY...WHILE THE GFS PLACES IT IN IOWA AND ECMWF IS THE SLOWEST
HOLDING IT BACK ALONG THE KANSAS/NEBRASKA BORDER. HOWEVER...THE
TRACK IS FAIRLY CONSISTENT WITH THE LOW TRACKING ACROSS THE FORECAST
AREA. WITH THESE DIFFERENCES STILL DIFFICULT TO DISCERN PRECIPITATION
TYPES THIS FAR OUT...BUT LATEST TRENDS WOULD SUGGEST BEST CHANCES
FOR ANY ACCUMULATING SNOW TO BE OVER THE WESTERN AND NORTHERN AREAS.
WILL CONTINUE TO MENTION RAIN/SNOW POSSIBILITY. ONCE SYSTEM
EXITS..QUIET BUT COLD WEATHER EXPECTED THURSDAY NIGHT INTO SATURDAY.
&&
.AVIATION...THROUGH 06Z MONDAY
1137 PM CST SAT DEC 10 2011
VFR CONDITIONS EXPECTED THROUGH THE PERIOD BUT THE WINDS WILL BE
THE BIGGEST CONCERN...ESPECIALLY TONIGHT. THE RIVER VALLEY HAS
DECOUPLED ENOUGH THAT WIND SHEAR IS LIKELY OCCURRING. SUSTAINED
WINDS AT KLSE HAVE BEEN RUNNING JUST UNDER 10 KNOTS WHILE THE VWP
FROM KARX SUGGEST WINDS OF 35 TO 40 KNOTS AT 3K FEET. THE BLUE
RIVER PROFILER SHOWS VERY SIMILAR WINDS AND SUGGEST THAT AT 2K
FEET THE WIND SPEEDS ARE NEAR 40 KNOTS. BOTH THE 11.00Z NAM AND
11.03Z RUC BUFKIT SOUNDINGS HOLD THE WINDS AT 2K FEET AT OR ABOVE
30 KNOTS INTO SUNDAY MORNING...SO WILL CONTINUE WITH THE INCLUSION
OF WIND SHEAR AT KLSE. SUSTAINED WINDS AT KRST ARE AROUND 15 KNOTS
AND AN AIRCRAFT SOUNDING OUT OF KMSP THIS EVENING AND THE 00Z KMPX
SOUNDING DO NOT SHOW AS STRONG OF WINDS AT 2K FEET...AROUND 25 TO
30 KNOTS...SO HAVE NOT INCLUDED THE WIND SHEAR FOR KRST.
CONDITIONS EXPECTED TO DETERIORATE PRETTY QUICKLY DURING THE
OVERNIGHT HOURS SUNDAY...JUST BEYOND THIS TAF PERIOD. MVFR CLOUDS
EXPECTED TO MOVE IN ALONG WITH THE POSSIBILITY OF FZDZ DEVELOPING
BEFORE SUNRISE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CST SUN DEC 11 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
904 PM MST MON DEC 12 2011
.UPDATE...EVENING WATER VAPOR IMAGERY SHOWED THE UPPER LOW PRESSURE
SYSTEM SLIDING SOUTH OFF THE SOUTH CENTRAL CALIFORNIA COAST WITH
PACIFIC MOISTURE STREAMING NORTH-NORTHEAST INTO THE CENTRAL/SOUTHERN
ROCKIES AND GREAT BASIN. THE REGIONAL SURFACE ANALYSIS PLACED A
WEAK STATIONARY FRONT FROM THE SOUTHERN LARAMIE RANGE INTO EASTERN
COLORADO AND THEN NORTHEAST INTO SOUTHERN NEBRASKA. WEAK MOIST
SOUTHEASTERLY FLOW OVERRUNNING THE BOUNDARY WAS RESULTING IN AN
EXTENSIVE LOW STRATUS DECK FROM WESTERN SOUTH DAKOTA INTO THE
WESTERN NEBRASKA PANHANDLE. THE 01Z HRRR MODEL OUTPUT INDICATES
GRADUAL WESTWARD EXPANSION AND LOWERING OF THE STRATUS WITH
AREAS OF FREEZING FOG AFFECTING THE LEE OF THE LARAMIE RANGE AND
HIGH PLAINS OF SOUTHEAST WYOMING LATER TONIGHT. ALSO...BUFKIT AND
MODEL SOUNDING DATA SUGGESTS A GRADUAL DEEPENING OF A SUBFREEZING
LAYER JUST BELOW A PRONOUNCED LOW LEVEL INVERSION ACROSS THE
SOUTHEAST 1/4 OF THE CWA BY 12Z TUESDAY. HAVE UPDATED THE WEATHER
GRIDS TO INSERT PATCHY FREEZING DRIZZLE FOR THE SOUTHERN PORTIONS
OF THE WESTERN PANHANDLE TUESDAY MORNING. NOT EXPECTING ANY
ACCUMULATIONS OR IMPACTS AT THIS TIME. THE FOG WILL BECOME LOCALLY
DENSE LATER TONIGHT...ESPECIALLY FOR THE WESTERN PANHANDLE WHERE
VISIBILITIES MAY DROP TO 1/2 MILE OR LESS AT TIMES. ONE TO THREE
MILE VISIBILITY WILL BE POSSIBLE OVER SOUTHEAST WYOMING.
&&
.PREV DISCUSSION... /ISSUED 523 PM MST MON DEC 12 2011/
AVIATION...00Z TAF ISSUANCE...LIFR CONDITIONS PERSIST AT CHADRON.
THESE LOW CONDITIONS WILL GRADUALLY OVERSPREAD THE REMAINDER OF THE
PANHANDLE AND EXTREME SOUTHEAST WYOMING TONIGHT PER THE LATEST
HRRR MODEL OUTPUT. THE NAM SHOWS SOME MVFR TO IFR CONDITIONS
DEVELOPING ACROSS CARBON COUNTY OVERNIGHT. THE LOW CEILINGS
AND VISIBILITIES WILL LIKELY LINGER THROUGH LATE TUESDAY MORNING
BEFORE IMPROVING TO MVFR OR BETTER. LIGHT SOUTH TO SOUTHEAST
WINDS TONIGHT WILL VEER TO SOUTHWEST TUESDAY MORNING.
PREV DISCUSSION... /ISSUED 235 PM MST MON DEC 12 2011/
SHORT TERM...TONIGHT THROUGH THURSDAY...
FOR THIS FORECAST THE CURRENT UPPER LOW CURRENTLY OVER CENTRAL
CALIFORNIA WILL MOVE NORTHEAST AND ACROSS THE ROCKIES. THE FEATURE
WILL SLOWLY FILL AS IT MOVES NORTHEAST AND THE TROUGH AXIS WILL BE
EAST OF THE CWA LATE WEDNESDAY AFTERNOON OR WEDNESDAY EVENING.
DURING THAT SAME TIME...SURFACE UPSLOPE WIND FLOW WILL PERSIST OVER
MUCH OF THE CWA. AS THE PLAINS SURFACE HIGH MOVES FURTHER EAST...
THE BOUNDARY LAYER WINDS WILL TURN TO MORE SOUTHWEST TUESDAY
AFTERNOON. PRIOR TO THAT...WIDESPREAD LOW CLOUDS AND FOG WILL
SPREAD AND DEVELOP OVER MUCH OF THE CWA BY 06Z. CURRENT AND
FORECAST RAOBS INDICATE THAT THE CLOUD DEPTH WILL BE BETWEEN 1000
AND 1500 FEET WHICH SHOULD NOT BE ENOUGH FOR FLURRIES OF FREEZING
DRIZZLE. THE SOUTHWEST BOUNDARY LAYER WINDS TUESDAY AFTERNOON
SHOULD HELP DISSIPATE THE LOWER CLOUDS AND FOG OVER THE EAST PART OF
THE CWA. WITH THE SHORTWAVE TROUGH PASSAGE ON WEDNESDAY
AFTERNOON...NORTHWEST SURFACE WINDS WILL INCREASE WITH SOME GUSTS
BETWEEN 30 AND 40 MPH. THOSE WINDS WILL PERSIST OVER AREAS ALONG
AND EAST OF THE LARAMIE RANGE THROUGH THURSDAY. MOST OF ANY
PRECIPITATION WILL OCCUR OVER AND NEAR THE SNOWY AND SIERRA MADRE
RANGES THROUGH THURSDAY AND WILL BE IN THE FORM OF LIGHT SNOW OR
FLURRIES. THERE MAY BE ENOUGH LIFT AS WELL OVER THE SOUTHEAST
QUARTER OF THE CWA FOR LATER TONIGHT AND WEDNESDAY MAINLY DUE TO THE
LOCATION OF THE 300 MB JET...HOWEVER MOISTURE DEPTH WILL BE
LACKING.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
12/12Z GFS AND ECMWF SIMILAR SYNOPTICALLY AT 500 MB...THUS MODERATE
TO HIGH CONFIDENCE IN THEIR RESPECTIVE SOLUTIONS.
WEDNESDAY NIGHT/THURSDAY...OUR COUNTIES WILL BE IN BETWEEN SYSTEMS...
THUS DRY. LOOKS LIKE ENOUGH MID/HIGH CLOUDS IN ADVANCE OF SHORTWAVE
TROUGH ALOFT OVER THE GREAT BASIN STATES TO KEEP OUR HIGH
TEMPERATURES IN THE 30S.
FRIDAY...NEXT COLD FRONT PLOWS ACROSS ALONG WITH CHANCES FOR SNOW...
THOUGH SNOW COVERAGE AND INTENSITY WILL BE LIMITED AS THE ENERGY
WITH THE SHORTWAVE TROUGH ALOFT IS SPLIT AND SHEARED WITH MOST OF
THE ENERGY REMAINING SOUTH OF WYOMING.
SATURDAY...CUTOFF LOW ALOFT WILL LIE TO OUR SOUTH WITH PRECIPITATION
OVER ARIZONA AND NEW MEXICO. DRY ACROSS OUR COUNTIES WITH SURFACE
LEE TROUGHING.
SUNDAY...TROUGH ALOFT OPENS UP AND MOVES ACROSS COLORADO AND NEW
MEXICO WITH PRECIPITATION TO THE SOUTH OF WYOMING AND NEBRASKA. LACK
OF CLOUD COVER ALONG WITH 1000-500 MB THICKNESSES NEAR 5490 METERS
WILL HELP HIGH TEMPERATURES REACH THE 30S AND MID 40S.
MONDAY...NEXT COLD FRONT MOVES ACROSS OUR COUNTIES WITH HIGH
TEMPERATURES BACK IN THE 20S AND 30S. LOOKS LIKE ENOUGH LOW AND MID
LEVEL MOISTURE FOR SCATTERED COVERAGE OF SNOW ACROSS THE NORTHERN
LARAMIE...SNOWY AND SIERRA MADRE RANGES...DRY ELSEWHERE.
FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE CWA THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL BE NEAR NORMAL OVERALL AND...OUTSIDE OF
WEDNESDAY...WINDS WILL BE FAIRLY LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...WEILAND
LONG TERM...RUBIN
AVIATION/UPDATE...JAMSKI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
330 AM EST TUE DEC 13 2011
.DISCUSSION...
TODAY-TONIGHT...
LARGE H100-H70 HI PRES RIDGE OVER THE SERN CONUS WILL SLOWLY WEAKEN
BUT WILL REMAIN THE DOMINANT WX FEATURE FOR THE FL PENINSULA AS IT
GENERATES A DEEP AND STEADY NE FLOW ACRS THE REGION. THESE WINDS
WILL PUSH DRIER AIR N OF THE BAHAMAS INTO CENTRAL FL THRU THE
DAY...LATEST RUC ANALYSIS SHOWS H100-H70 MEAN RH VALUES BLO 70PCT
AND H85-H50 VALUES BLO 50PCT.
ALOFT...A STRONG H85-H50 ANTICYCLONE OVER THE GOMEX WILL LIFT INTO
THE DEEP SOUTH. THIS WILL INCREASE THE STRENGTH OF A WEAK SUBSIDENCE
INVERSION IN THE H80-H60 LYR ACRS CENTRAL FL WHILE SIMULTANEOUSLY
PULLING DRY MID LVL AIR DOWN FROM THE N. MINIMAL H50 VORTICITY AND
H25 CONVERGENCE WILL FURTHER HAMPER ANY ORGANIZED PRECIP
KMLB PRECIP TREND HAS BEEN DIMINISHING STEADILY OVER THE PAST SVRL
HRS THOUGH KJAX SHOWS ONE REMAINING POCKET OF PRECIP PUSHING ONSHORE
N OF FLAGLER BEACH. MOST OF THIS PRECIP HAS FORMED OVER THE GULF
STREAM AND WILL WEAKEN AND DIMINISH AS IT MOVES OVER THE COOLER
SHELF WATERS. WILL KEEP SMALL COASTAL POPS IN THE FCST THRU EARLY
AFTN AS REMAINING DEEP MOISTURE PUSHES SW OF THE AREA...BUT IMPACT
WILL BE MINIMAL. DEEP/STEADY ONSHORE FLOW WILL MAINTAIN A STRONG
MARITIME INFLUENCE ACRS THE AREA...TEMPS WILL CONTINUE ABV CLIMO
WITH MAXES IN THE M/U70S...MINS M/U50S INTERIOR AND L/M60S ALONG THE
COAST.
WED-FRI...
AREA OF HIGH PRESSURE CENTERED NEAR THE MID ATLANTIC COAST WED WILL
SHIFT SOUTHEASTWARD WITH RIDGE AXIS BUILDING TOWARD NORTH FLORIDA
INTO LATE WEEK. THIS WILL ALLOW THE ELEVATED EASTERLY FLOW OVER
CENTRAL FLORIDA TO WEAKEN INTO FRI. BREEZY CONDS WILL STILL BE
LIKELY ALONG THE COAST WED WITH WINDS THEN AROUND 10-15 MPH OR LESS
BOTH THURS AND FRI. THE STRONGER ONSHORE FLOW WED MAY STILL ALLOW
FOR A FEW ONSHORE MOVING SPRINKLES BUT WITH A DRIER AIRMASS IN PLACE
DO NOT EXPECT ANY ACCUMULATING RAINFALL. OTHERWISE THE REST OF THE
WEEK LOOKS DRY WITH PARTLY CLOUDY SKIES AND ABOVE NORMAL TEMPS.
SAT-MON...
A S/W TROUGH PUSHING OFF THE EASTERN SEABOARD DEVELOPS AN AREA OF
LOW PRESSURE TOWARD THE CAROLINAS SATURDAY. LONG TERM MODELS MOVE
THIS LOW PRESSURE INTO THE ATLANTIC WITH A WEAK COLD FRONT PUSHING
ACROSS CENTRAL FLORIDA SAT NIGHT INTO SUN. MOISTURE ASSOCIATED WITH
THIS FRONT IS VERY WEAK WITH PW VALUES JUST BARELY OVER AN INCH.
WILL KEEP A SLIGHT CHANCE OF SHOWERS OVER THE AREA WITH THIS FRONTAL
PASSAGE...HOWEVER LOOKS LIKE BEST CHANCE FOR ANY PRECIPITATION WILL
PROBABLY BE LIMITED TO THE WARMER GULF STREAM WATERS. MODELS ONLY
INDICATING A SLIGHT COOL DOWN WITH THIS FRONT WITH MORE NORMAL TEMPS
SUN AND MON.
&&
.AVIATION...
THRU 13/15Z...WDSPRD IFR CIGS/AREAS LIFR CIGS NW OF I-4...PREVAILING
CIGS AOA FL030 ELSEWHERE WITH BRIEF MVFR CIGS/VSBYS IN ISOLD SHRAS S
OF KVRB. AFT 13/15Z...VFR ALL SITES WITH CIGS BTWN FL040-060...NE
SFC WND G22-25KTS THRU 13/23Z.
&&
.MARINE...
TODAY-TONIGHT...HI PRES RIDGE OVER THE SE CONUS WILL MAINTAIN A
MODERATE TO FRESH NE BREEZE ACRS THE LCL ATLC. SFC/BNDRY LYR WINDS
WILL DIMINISH BLO 20KTS AFT MIDNIGHT AS THE RIDGE BEGINS TO
WEAKEN...THOUGH A LONG NE FETCH OVER THE W ATLC WILL CONTINUE TO
PUSH A LARGE SWELL INTO THE E FL COAST. SEAS 6-8FT NEARSHORE AND
8-10FT OFFSHORE THRU DAYBREAK WED. WAVE PDS WILL OPEN UP AS THE
WINDS DIMINISH...INCREASING FROM 8-9SEC TODAY TO 9-10SEC TONIGHT.
FULL SCA WILL CONTINUE THRU 09Z...SCA FOR SEAS AFT 09Z.
WED-SAT...ELEVATED ONSHORE WINDS WILL LIKELY CONTINUE UP TO 15-20
KTS WED AND WED NIGHT AND COMBINE WITH A LONG NORTHEASTERLY FETCH TO
KEEP SEAS UP TO 7 TO 9 FT. RIDGE AXIS BUILDING TOWARD NORTH FLORIDA
INTO LATE WEEK WILL THEN WEAKEN THE ONSHORE FLOW WITH SEAS SLOWLY
SUBSIDING INTO THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 61 75 59 / 20 10 10 10
MCO 78 58 78 58 / 10 0 10 10
MLB 78 67 77 65 / 20 10 10 10
VRB 78 66 77 65 / 20 10 10 10
LEE 76 56 77 57 / 10 0 10 10
SFB 78 58 77 58 / 10 0 10 10
ORL 78 59 77 59 / 10 0 10 10
FPR 78 66 77 64 / 20 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR COASTAL
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20
NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20
NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET OUT 20 NM-WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD
COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO
JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD
COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM WEDNESDAY TO
7 AM EST THURSDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO
VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM
SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM
VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM
OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60
NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO
SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...WEITLICH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1257 AM EST TUE DEC 13 2011
.SYNOPSIS...
SURFACE HIGH PRESSURE CENTERED NORTH OF THE AREA WILL PERSIST
THROUGH MID WEEK BEFORE WEAKENING AND SHIFTING OFFSHORE LATE IN
THE WEEK. A COLD FRONT COULD STALL OVER OR NEAR THE REGION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DRY CONDITIONS ARE EXPECTED OVERNIGHT AS HIGH PRESSURE HOLDS FIRM
ACROSS MUCH OF THE SOUTHEAST UNITED STATES. HAVE MADE SOME FAIRLY
SIZABLE CHANGES TO THE GRIDS AND TEXT PRODUCTS FOR THE OVERNIGHT
PERIOD AS SHORTER TERM TRENDS ARE FINALLY BECOMING MORE APPARENT.
CONFIDENCE IS INCREASING THAT THE POTENTIAL FOR A WIDESPREAD
STRATUS/FOG EVENT IS DIMINISHING WITH TIME AS THE LOWER
TROPOSPHERE CONTINUES TO DRY OUT. 13/01Z RUC SOUNDINGS SUGGEST AN
ENHANCED BOUNDARY LAYER WIND FIELD WILL LIKELY SEVERELY CURTAIL
THE WIDESPREAD FOG POTENTIAL AND ALTHOUGH PATCHES OF STRATUS ARE
LIKELY TO REFORM PRIOR TO DAYBREAK...SUSPECT THE THICKEST STRATUS
DECK ALONG WITH SOME PATCHY FOG WILL REMAIN MAINLY S OF I-16 IN
GEORGIA. WILL GO WITH A GENERAL PARTLY CLOUDY SKY FORECAST THROUGH
SUNRISE FOR THIS REASON...ALTHOUGH THERE WILL BE SOME FAIRLY
SIZABLE CLEAR PERIODS THIS EVENING. LOWS FROM THE UPPER 30S WELL
INLAND TO THE MID 40S AT THE COAST LOOK ON TRACK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
PRETTY GOOD MODEL AGREEMENT FOR MID WEEK WITH SURFACE HIGH PRESSURE
CENTERED NORTH OF THE AREA SLOWLY SHIFTING EAST INTO THE ATLANTIC.
MEANWHILE...HIGH PRESSURE ALOFT WILL BECOME STRONGER THROUGH
WEDNESDAY BEFORE WEAKENING THURSDAY AS A COLD FRONT BEGINS TO
APPROACH FROM THE WEST. EXPECT A DRY PERIOD WITH THE LACK OF DEEP
MOISTURE. TEMPERATURES WILL BE ON A SLOW WARMING TREND...REACHING
WELL ABOVE NORMAL LEVELS THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE UPPER LEVEL PATTERN WILL BECOME ZONAL LATE IN THE WEEK...ALLOWING
A BACKDOOR COLD FRONT TO SLOWLY SINK SOUTH INTO THE AREA OVER THE
WEEKEND. GUIDANCE REMAINS IN DISAGREEMENT AS TO WHEN THE FRONT
WILL PUSH THROUGH THE AREA SO HAVE MADE NO CHANGES TO THIS PORTION
OF THE FORECAST WHICH CURRENTLY HAS SLIGHT RAIN CHANCES FRIDAY
NIGHT THROUGH SATURDAY NIGHT. UPPER LEVEL HIGH PRESSURE WILL THEN
RETURN BRIEFLY EARLY NEXT WEEK BEFORE THE NEXT STORM SYSTEM BEGINS
TO APPROACH FROM THE WEST. TEMPERATURES GENERALLY ABOVE NORMAL
THROUGH THE PERIOD...EVEN BEHIND THE COLD FRONT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SKIES HAVE CLEARED OVER THE COASTAL CORRIDOR EARLY THIS MORNING
AND VFR CONDITIONS WILL PERSIST BUT THERE COULD BE AN EXCEPTION A
FEW HOURS AROUND DAYBREAK IF FOG AND/OR STRATUS CLOUDS DEVELOP.
LATEST DATA SUGGESTS ALMOST A COIN-FLIP SCENARIO AS LOWEST LEVEL
NNE WINDS A BIT STRONG DESPITE FOG STABILITY INDICES BELOW 15 ON
FORECAST SOUNDINGS AT BOTH TERMINALS JUST BEFORE DAWN. GIVEN ALL
THE RAIN AT KSAV...WE HIT SOME IFR POTENTIAL AND MAINTAINED JUST
CURSORY MENTION OF MVFR VSBYS AND A FEW SCATTERED STRATUS AT KCHS.
EXTENDED AVIATION OUTLOOK...PATCHY MVFR CONDITIONS POSSIBLE IN
EARLY MORNING FOG ON WED...OTHERWISE MAINLY VFR.
&&
.MARINE...
BUOY AND PILOT BOAT REPORTS INDICATE SEAS HAVE DROPPED BELOW 6 FT
ACROSS THE SOUTH CAROLINA LEGS SO THE SMALL CRAFT ADVISORY HAS
BEEN CANCELLED FOR AMZ350-352. LOOKS LIKE MARGINAL 6 FT SEAS WILL
CONTINUE FOR SEVERAL MORE HOURS OVER THE GEORGIA NEARSHORE WATERS
WHERE FLAGS REMAIN IN FORCE UNTIL 5 AM TUESDAY. SOLID SMALL CRAFT
ADVISORY CONDITIONS WILL PERSIST OVER THE GEORGIA OFFSHORE WATERS
THROUGH THE NIGHT.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL REMAIN CENTERED NORTH
OF THE WATERS THROUGH WEDNESDAY BEFORE SHIFTING EAST ON THURSDAY. A
COLD FRONT WILL THEN APPROACH LATE IN THE WEEK BEFORE EVENTUALLY
PUSHING THROUGH THE AREA OVER THE WEEKEND. EXPECT WINDS TO DECREASE
SIGNIFICANTLY TUESDAY AS THE HIGH WEAKENS. SEAS WILL SLOWLY SUBSIDE
ALONG WITH THE WINDS WITH ADVISORY CONDITIONS PERSISTING BEYOND 20
NM THROUGH WEDNESDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
AMZ354.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1116 PM CST MON DEC 12 2011
.AVIATION...
FOR THE 06Z TAF ISSUANCE...
MOIST UPSLOPE FLOW CONTINUE ACROSS SOUTHWEST KANSAS WITH
VISIBILITIES ALREADY FALLING TO 1/4 MILE AT GCK AND DDC. THIS AREA
WAS WHERE MOISTURE APPEARS TO BE POOLING NEAR A SURFACE BOUNDARY
WHICH EXTENDED FROM NEAR SYRACUSE TO SCOTT CITY TO WAKEENEY. THE
RUC AND NAM WERE IN GOOD AGREEMENT WITH THE LOW LEVEL MOISTURE IN
THIS AREA INCREASING AND DEEPENING THROUGH THE PREDAWN HOURS. AS A
RESULT THE DEPTH OF THIS MOIST LAYER IS EXPECTED TO EXCEEDS 1KM
AFTER 09Z SO IN ADDITION TO THE FOG SOME DRIZZLE CAN ALSO BE
EXPECTED. CEILINGS OVER THE NEXT 12-15 HOURS ARE NOT EXPECTED TO
IMPROVE MUCH BASED ON THE NAM BUFR SOUNDINGS BUT VSBYS SHOULD
START TO IMPROVE BY 15Z.
&&
.PREV DISCUSSION... /ISSUED 725 PM CST MON DEC 12 2011/
UPDATE...
THE LATEST 00 UTC KDDC SOUNDING IS INDICATING A NEARLY SATURATED
LAYER FROM NEAR THE SURFACE TO 5,000FT, ASSOCIATED WITH THE STRATUS
ACROSS THE AREA THIS EVENING. ABOVE THAT IS A TREMENDOUSLY DRY AND
DEEP LAYER FROM AROUND 875 MB THROUGH THE MIDDLE TROPOSPHERE. THE
KDDC RADAR ECHOES THAT HAVE BEEN MOVING ACROSS THE WESTERN AND
SOUTHWEST COUNTIES THIS EVENING ARE PRIMARILY ELEVATED ECHOS WITH NO
PRECIPITATION. WE`VE REMOVED POPS AND RAIN SHOWERS/DRIZZLE
ALTOGETHER FOR THIS EVENING, AND RAMPED UP POPS ACROSS THE
SOUTHEAST 1/2 OF THE FORECAST AREA AFTER MIDNIGHT TO CLOSER FOLLOW
THE HOURLY RAPID REFRESH RUC MODEL. ADDITIONALLY, AREAS OF FOG HAVE
BEEN INTRODUCED ON A WIDER SCALE GIVEN THE CURRENT NAM AND HRRR`S
VSBYS AND TRENDS WITHING THE SURFACE MOISTURE CONVERGENCE ZONE. -RUSSELL
PREV DISCUSSION... /ISSUED 319 PM CST MON DEC 12 2011/
DISCUSSION...
DAYS 1-2...
THE UPPER LEVEL LOW CURRENTLY ACROSS SOUTHERN CALIFORNIA WILL START
TO EJECT EAST NORTHEAST ACROSS THE FOUR CORNERS REGION TOMORROW AND
ACROSS THE CENTRAL PLAINS BY THURSDAY MORNING. A STRONG UPPER LEVEL
JET WILL ACCOMPANY THIS SYSTEM ENHANCING LIFT ACROSS OUR CWA TONIGHT
INTO WEDNESDAY MORNING. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
BE FOUND ACROSS THE EASTERN THIRD OF THE UNITED STATES. AT THE
SURFACE...AN AREA OF HIGH PRESSURE WILL BE FOUND ACROSS THE GULF OF
MEXICO AND CONTINUE TO BRING LOWER TO MID LEVEL MOISTURE NORTH INTO
OUR AREA. A SURFACE COLD FRONT IS ANTICIPATED TO CONTINUE TO MOVE
SOUTH ACROSS KANSAS THIS AFTERNOON AND STALL OUT ACROSS OUR CWA THIS
EVENING. THIS FRONTAL BOUNDARY WILL THEN MOVE NORTHWARD OVERNIGHT
AND BE POSITIONED ACROSS THE KS/NE BORDER BY TOMORROW MORNING. RAIN
CHANCES INCREASE OVERNIGHT AND LIGHT RAIN IS POSSIBLE ACROSS
SOUTHEAST PORTIONS OF THE CWA BY MIDNIGHT SPREADING ACROSS THE
REMAINDER OF THE CWA BY TOMORROW MORNING. PATCHY FOG IS ALSO
POSSIBLE OVERNIGHT BUT SHOULD DISSIPATE BY MORNING. LAST, THERE
COULD BE A FEW AREAS THAT EXPERIENCE LIGHT FREEZING RAIN ACROSS
HAMILTON, KEARNY, SCOTT, AND TREGO COUNTIES AFTER MIDNIGHT BUT NO
ACCUMULATION OF ICE IS EXPECTED AS SURFACE TEMPERATURES WILL BE
ABOVE FREEZING.
MOISTURE CONTINUES TO ADVECT NORTHWARD ACROSS THE AREA TOMORROW
AHEAD OF THE UPPER LEVEL TROUGH ALLOWING CLOUDY SKIES AND RAIN
CHANCES TO CONTINUE THROUGHOUT THE DAY. RAIN CHANCES RANGE FROM 50
PERCENT IN THE WEST TO OVER 70 PERCENT IN THE EAST. AN AREA OF LOW
PRESSURE IS EXPECTED TO MOVE FROM NORTHEASTERN NEW MEXICO TOMORROW
AFTERNOON AND SHIFT EAST INTO SOUTHEAST NEBRASKA BY WEDNESDAY
AFTERNOON. THIS WILL PUSH A COLD FRONT THROUGH THE AREA TOMORROW
NIGHT INTO WEDNESDAY MORNING. I HAVE KEPT IN THE WORDING OF ISOLATED
THUNDER ACROSS EASTERN PORTIONS OF THE CWA TOMORROW NIGHT ENDING IN
THE LATE MORNING AS THE COLD FRONT MOVES INTO WICHITA`S WFO. POPS
DECREASE FROM WEST TO EAST TOMORROW NIGHT INTO WEDNESDAY AND BELOW
15 PERCENT ACROSS THE ENTIRE CWA BY WEDNESDAY AFTERNOON. CLOUDS WILL
ALSO BE ON THE DECREASE AS THE SYSTEM EXITS OFF TO THE EAST LEAVING
PARTLY CLOUDY SKIES BY WEDNESDAY EVENING.
LOWS TONIGHT WILL RANGE FROM THE LOWER 30S IN THE NORTHWEST TO LOWER
40S IN THE SOUTHEAST WITH HIGHS TOMORROW WILL RISING INTO THE MID TO
UPPER 40S. OVERNIGHT LOWS TOMORROW NIGHT COULD ACTUALLY CLIMB ABOVE
TUESDAYS HIGHS DEPENDING ON DEWPOINTS. I WILL CONTINUE NEARLY STEADY
TEMPERATURES IN THE 40S OVERNIGHT WITH TH EXCEPTION OF NORTHEAST
PORTIONS OF THE CWA WHERE LOWS COULD DROP INTO THE UPPER 30S. HIGHS
ON WEDNESDAY ARE ANTICIPATED TO RANGE FROM THE LOWER 50S IN THE
NORTHWEST TO NEAR 60 IN THE SOUTHEAST.
DAYS 3-7...
THE MEDIUM RANGE MODELS SHOW A SECONDARY SHORTWAVE TROUGH LIFTING
OUT OF THE DESERT SOUTHWEST AND NORTHERN MEXICO ACROSS THE SOUTHERN
PLAINS LATER THIS WEEK. THE ENERGY WITH THIS WAVE IS PRETTY FAR
SOUTH AND WITH ALL THE BEST LOW LEVEL MOISTURE BEING SHUNTED SOUTH
BY THE MIDWEEK SYSTEM...THE DRY FORECAST LOOKS GOOD. THE MODELS SHOW
ANOTHER ANTICYCLONIC WAVE BREAK OCCURRING LATE THURSDAY AND THURSDAY
NIGHT. A SHORTWAVE TROUGH NOW SOUTHWEST OF THE ALEUTIAN ISLANDS IS
FORECAST TO TOP THE EASTERN PACIFIC RIDGE AND DIG SOUTH ACROSS THE
WESTERN STATES. THE ECMWF AND CANADIAN MODELS HAVE BEEN FAIRLY
CONSISTENT WITH THE TRACK AND TIMING OF THIS SYSTEM AS IT CLOSES OFF
AND HANGS BACK IN THE SOUTHWEST BEFORE LIFTING OUT TOWARD THE
CENTRAL/SOUTHERN PLAINS LATE NEXT WEEKEND. THE GFS HAS TENDED TO BE
MORE PROGRESSIVE AS IT TENDS TO DO. YESTERDAYS GFS ENSEMBLE MEMBERS
WERE MOSTLY SLOWER THAN THE OPERATIONAL RUN. TODAYS GFS ENSEMBLE
MEMBERS WERE STILL A LITTLE SCATTERED BUT MOSTLY KEEP THE SYSTEM
SLOWER LIKE THE OTHER MODELS. THE 12Z GFS OPERATIONAL MODEL NOW
APPEARS TO BE IN BETTER AGREEMENT WITH THE OTHERS.
GIVEN THE LATEST MODEL OUTPUT...THINK THAT THE ONSET OF ANY CHANCES
FOR PRECIPITATION WILL NOT OCCUR UNTIL SUNDAY AT THE EARLIEST AND
MORE LIKELY SUNDAY NIGHT IF THE SLOWER MODEL SOLUTION PANS OUT.
THERE IS SOME UNCERTAINTY THIS FAR OUT AS TO WHAT PRECIPITATION TYPE
WILL BE AS THE GFS SHOWS ABOVE FREEZING TEMPERATURES FOR MOST OF THE
EVENT. SOME DYNAMIC COOLING COULD RESULT IN A RAIN/SNOW MIX OVER TO
SNOW AND WILL SHOW THAT IN THE GRIDS ROUGHLY NORTHWEST OF A MEADE TO
LARNED LINE.
WITH NO SIGNIFICANT COLD AIR INTRUSIONS INDICATED BY THE
MODELS...TEMPERATURES SHOULD STAY FAIRLY SEASONAL FOR DECEMBER.
FOR WEEK TWO WILL MAINTAIN THE NEAR NORMAL TEMPERATURES AND
PRECIPITATION AS THE MODELS ARE INDICATING THE POSSIBILITY FOR
ANOTHER WAVE DROPPING INTO THE SOUTHWEST AND CLOSING OFF AROUND
DECEMBER 21ST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 47 45 53 / 60 60 60 30
GCK 35 46 44 50 / 50 60 60 20
EHA 37 47 42 51 / 50 60 60 10
LBL 39 49 47 53 / 50 60 60 20
HYS 34 45 43 51 / 40 60 60 50
P28 41 49 47 60 / 70 80 80 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CST /7 AM MST/ TUESDAY FOR KSZ030-
043>045-061>064-074>078.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 AM EST TUE DEC 13 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.UPDATE...
ISSUED A FREEZING RAIN ADVISORY THROUGH TUE MORNING...SINCE DRIZZLE
WAS FALLING OVER MUCH OF CENTRAL AND WRN UPPER MI WITH TEMPS ALREADY
AT FREEZING INLAND. HARD TO TELL WHEN DRIZZLE WILL STOP...BUT SHOULD
CONTINUE INTO TUE MORNING AS LOW LEVEL MOISTURE HANGS OVER THE
AREA...THE DGZ REMAINS DRY...AND TEMPS SLOWLY FALL TONIGHT.
&&
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA WITH SRN BRANCH SW FLOW ALF OVER THE GRT LKS BTWN RDG OVER
THE ERN CONUS AND A WRN TROF. A SHRTWV EMBEDDED IN THIS SW FLOW IS
OVER MN AND CAUSING AN AREA OF -RA OVER WI INTO SE UPR MI...WHERE
DEEPER MSTR IS PRESENT. SOME SN IS MIXING IN WITH THIS PCPN IN THE
PRESENCE OF DYNAMIC COOLING ACCOMPANYING THE SHRTWV EVEN THOUGH SFC
TEMPS ARE ABV 32. ISSUED SPS THIS AFTN TO ACCOUNT FOR PERIODS OF
HEAVY SN/SLUSHY ACCUMS IN A SWATH OVER THE CNTRL WHERE DYNAMIC
COOLING RELATED TO AREA OF H85-7 FGEN IS MOST PRONOUNCED. OTRW...
TEMPS OVER THE ENTIRE CWA ARE WELL ABV NORMAL AND IN THE 30S.
ABUNDANT LLVL MSTR WITH DWPTS ALSO IN THE 30S IN LGT SW SFC FLOW HAS
CAUSED QUITE A BIT OF LO CLD/FOG OVER THE CWA...BUT A COLD FNT TO
THE N ASSOCIATED WITH A DISTURBANCE IN THE ARCTIC BRANCH OVER CAN IS
PRESSING SLOWLY SWD INTO LK SUP. THE COLD AIR BEHIND THIS FNT IS
QUITE SHALLOW PER THE 12Z INL RAOB...BUT SFC TEMPS AT NOON FALL
QUITE SHARPLY FM ARND 35 OVER THE KEWEENAW AND AHEAD OF THE FNT TO
19 AT THUNDER BAY ONTARIO.
&&
.SHORT TERM DISCUSSION /TNGT AND TUE/...
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN CHCS/PTYPE ASSOCIATED
WITH SHRTWV LIFTING INTO WI. FOCUS FOR LATER TNGT AND TUE SHIFTS TO
INFLUX OF COLDER/DRIER AIR FM THE N AND IMPACT ON THE WX.
TNGT...SHRTWV OVER WI AND ACCOMPANYING DYNAMICS/DEEPER MSTR ARE
PROGGED TO LIFT OUT AND EXIT THE ERN ZNS BY LATE EVNG...SO GOING
MORE WDSPRD MIXED PCPN OVER MAINLY THE SE HALF WL DIMINISH WITH MID
LVL SUBSIDENCE/DRYING OVERSPREADING THE FA. HOWEVER...INFLUX OF
SHALLOW COLD AIR FOLLOWING NW-SE PASSAGE OF SFC COLD FNT WL MAINTAIN
A SHARP LLVL INVRN AND PRESENT OVC ST/SC DECK. IN PLACES WITH
UPSLOPE WIND FLOW...OPTED TO MAINTAIN MENTION OF -DZ/-FZDZ WITH
SHALLOW MSTR WELL BLO THE DGZ AND UNDER SUBSIDENCE ALF. CONSIDERING
THE LLVL CHILL OBSVD UPSTREAM...TENDED TO GO TOWARD THE LO SIDE OF
GUIDANCE FOR TEMPS FOLLOWING THE COLD FROPA. EVEN SO...AIRMASS WL
NOT BE SUFFICIENTLY COLD TO SUPPORT LES WITH SHARP INVRN.
TUE...SHALLOW COLD WEDGE WL REMAIN IN PLACE WITH SLOWING VEERING
FLOW TO MORE ESE IN THE AFTN AS CENTER OF HI PRES IN ONTARIO DRIFTS
TO THE E. WITH COLD WEDGE GETTING A BIT MORE SHALLOW...SUSPECT
LINGERING -DZ/-FZDZ WL BE MORE TIED TO UPSLOPE FLOW OVER THE NCNTRL
WHERE THERE WL BE ADDITIONAL MOISTENING OFF LK SUP. EXPECT LTL
DIURNAL TEMP RISE WITH LINGERING LO CLD OVC.
.LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/...
ACTIVE MID TERM PORTION OF THE FORECAST...WITH A LOW PRESSURE SYSTEM
MOVING THROUGH THE AREA AROUND MID WEEK AND PROVIDING A WINTRY MIX
OF PCPN.
TUES NIGHT...UPPER RIDGE AXIS WILL BE SHIFTING E OF THE CWA THROUGH
THE NIGHT. SHOULD KEEP MUCH OF THE AREA DRY...ALTHOUGH PERSISTANT
LOW CLOUDS WILL BE COVERING MUCH OF THE AREA. WITH INCREASING
ISENTROPIC ASCENT AROUND THE 280 SFC AND DRY AIR ABOVE
5KFT...WOULDN/T BE SURPRISED IF THE SWRN HALF OF THE CWA EXPERIENCES
SOME DZ/FZDZ...SO HAVE PUT THE MENTION IN FOR MUCH OF THE NIGHT.
TRANSITIONED TO A RA/SN MIX ALONG THE WI BORDER OVERNIGHT...AS THE
280-300K ISENTROPIC ASCENT BEGINS TO MOVE INTO THE AREA. WITH THE
MOISTURE EATING AWAY AT THE DRY AIR...EXPECT THE DZ/RA TO QUICKLY
TRANSITION TO MAINLY SNOW ALONG THE BORDER AS ICE BECOMES PRESENT
AND THERE IS A NEARLY ISOTHERMAL LAYER AT/BELOW 0C FROM THE SFC TO
6KFT.
WITH THE MAIN TROUGH STILL WELL TO THE SW IN THE FOUR CORNERS
REGION...WEAK SHORTWAVE ENERGY WILL BE EJECTING NE TOWARDS THE AREA
ON WED. THIS WILL PUSH A WEAK LOW PRESSURE TROUGH ACROSS THE CWA
THROUGH THE DAY. BEST CHANCES OF PCPN ARE S AND E...CLOSER TO THE
MAIN PUSH OF THE SHORTWAVE...ALONG WITH H850-700 WAA AND ISENTROPIC
ASCENT. THIS AREA OF PCPN SHOULD QUICKLY MOVE NE THROUGH THE CWA
DURING THE MORNING AND EARLY AFTN AND LEAD TO A SLIGHTLY DRIER
PERIOD OVER THE W IN THE LATE AFTN BEFORE THE NEXT WAVE AFFECTS THE
AREA. DIFFICULTY IN THE FCST COMES FROM PCPN TYPE...AS THERE COULD
BE A MIXED BAG WITH THE PASSAGE OF THE SYSTEM. SOUNDINGS CONTINUE TO
SHOW A NEARLY ISOTHERMAL 0C LAYER FROM SFC TO 7KFT FOR THE
CENTRAL/WRN PORTIONS OF THE AREA...WHICH WOULD SUPPORT SNOW IN THE
MORNING. THEN AS SRLY WINDS INCREASE THROUGH THE DAY...LLVL TEMPS
LOOK TO RISE AND LEAVE THE LOWEST 2-4KFT ABOVE FREEZING /TOWARDS
2-3C/. AT THAT SAME TIME...THE DEEP MOISTURE EXITS THE AREA AND
THERE WILL LIKELY BE LITTLE/NO ICE POTENTIAL IN THE CLOUDS...SO HAVE
WENT MAINLY RAIN...WITH JUST A MENTION OF SNOW OVER THE N. MAY END
UP BEING JUST A -RA/DZ SITUATION IN THE LATE AFTN BEFORE NEXT WAVE
ARRIVES.
MAIN SHORTWAVE FROM THE SW FLOW ARRIVES ON WED NIGHT OVER THE ERN
CWA...WHICH MODELS RESPOND TO BY INTENSIFYING THE LOW OVER THE UPPER
GREAT LAKES. AT THE SAME TIME...NRN STREAM SHORTWAVE BEGINS TO ENTER
THE NRN PLAINS AND PHASES WITH THE SRN STREAM. MODELS HAVE A
NOTORIOUSLY TOUGH TIME WITH THESE EVENTS AND IT APPEARS THAT IT
CONTINUES WITH THIS SITUATION. ISSUES APPEAR WITH THE
TIMING/STRENGTH OF THE NRN STREAM WAVE...WHICH AFFECTS
INTENSITY/TRACK OF LOW. TRENDS IN THE GFS/ECMWF OVER THE LAST DAY OR
TWO HAVE BEEN FOR A WEAKER LOW TO TRACK ACROSS THE FAR ERN CWA WITH
A WEAKER NRN STREAM WAVE. WILL FOLLOW THAT TREND FOR THE WED NIGHT
AND THURS FORECAST...WITH AN EMPHASIS ON THE HPC PREFERRED GFS.
THEREFORE...HAVE THE HIGHEST POPS /80 PLUS/ OVER THE ERN HALF OF THE
CWA WITH THE BEST FORCING/MOISTURE. EXPECT THIS TO BE MAINLY RAIN
OVER THE EAST HALF...BUT IF THE ECMWF ENDS UP BEING CORRECT THERE
COULD BE SOME MIXING LATE.
FCST IS A LITTLE MORE TRICKY OVER THE W...SINCE IT IS ON THE FRINGE
OF THE BEST DEEP MOISTURE AND FORCING. IF PCPN OCCURS...HAVE A
FEELING THAT POTENTIAL FOR ICE IN THE CLOUDS IS LIMITED. HAVE
TRENDED TOWARDS MORE OF A RA SITUATION UNTIL THE COLDER AIR ARRIVES
TOWARDS DAYBREAK THURSDAY. DEPENDING ON HOW QUICKLY TEMPS FALL
DURING THE NIGHT AND INTO THURS MORNING...COULD SEE A PERIOD OF FZDZ
BEFORE TURNING TO ALL SNOW DURING THE MORNING.
THE LOW SHOULD THEN INTENSIFY OVER QUEBEC ON THURS...AS THE
SHORTWAVES PHASE. WITH SFC HIGH OVER THE NRN PLAINS AND JUST E OF
THE CANADIAN ROCKIES...EXPECT NW WINDS AND H850 TEMPS NEAR -12C TO
LEAD TO AT LEAST SOME LES DEVELOPING. INVERSION HEIGHTS AROUND
6-8KFT GIVES A DECENT CLOUD DEPTH...BUT WITH BEST FORCING BELOW THE
DGZ WILL LIMIT SNOW GROWTH. OPTED TO BUMP POPS UP HEADING INTO THE
AFTN...AS MORE FAVORABLE CONDITIONS FOR LES ARRIVE...ESPECIALLY
SINCE THE NRN CWA SHOULD BE SEEING WRAP AROUND MID-LVL MOISTURE FROM
THE LOW. FINALLY...SHOULD BE A BREEZY DAY ON THURS...WITH GUSTS
ALONG THE ERN LK SUPERIOR SHORELINE APPROACHING 40MPH.
DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/...
OVERALL...GOOD AGREEMENT IN THE EXTENDED MODELS ON THE OVERALL
PATTERN FOR THE EXTENDED PERIOD. ON THURS NIGHT...UPPER TROUGH WILL
BE PUSHING THROUGH THE AREA AND DROPPING H850 TEMPS TOWARDS -14C.
SHOULD STILL BE SOME MID-LVL MOISTURE OVER THE E BEFORE THE MOISTURE
EXITS THE AREA ON FRI AS THE INVERSION HEIGHTS FALL TOWARDS 5KFT
WITH HIGH PRESSURE RIDGE MOVING OVER THE WRN CWA. THUS...LES
INTENSITY SHOULD HIT IT/S PEAK THURS NIGHT...AS SHOWN IN LES
PARAMETER...BEFORE DIMINISHING IN INTENSITY THROUGH FRI. ONLY MADE
MINOR TWEAKS UP TO THE POPS OVER THE EAST AND THEN BUMPED UP TO HIGH
END CHANCE AND LOW LIKELY/S OVER THE NW WIND SNOW BELTS OVER THE
WEST FOR THURS NIGHT INTO FRI...ALTHOUGH THE CHANCES WILL DIMINISH
OVER THE W IN THE AFTN. IN ADDITION...WEAK SHORTWAVE ON FRI COULD
BRING SOME MID CLOUDS.
SFC HIGH PRESSURE RIDGE WILL QUICKLY MOVE EAST OF THE AREA ON FRI
NIGHT...WITH MODELS CONSISTENT ON A SHORTWAVE MOVING THROUGH THE
UPPER MISS VALLEY ON SAT. THIS WAVE WILL LIKELY DIVE S OF THE
CWA...AND CARRY THE BEST MOISTURE AND H850-500 Q-VECTOR CONV WITH
IT. OTHER THAN LINGERING LES OVER THE NW FAVORED LOCATIONS OVER THE
E IN THE MORNING BEFORE WIND SHIFT TO THE SW...WILL KEEP THE REST OF
THE CWA DRY.
UPPER RIDGE MOVING THROUGH SUNDAY...WITH H850 TEMPS RISING TOWARDS
1-4C. SHOULD LEAD TO ANOTHER WARM SUNDAY ACROSS THE AREA...BUT MAY
NOT BE QUITE AS WARM AS YESTERDAY/S HIGHS. DID BUMP UP TEMPS FROM
THE CONSENSUS OVER THE DOWNSLOPE AREAS NEAR LK SUPERIOR INTO THE
UPPER 30S. NEXT TROUGH WILL AFFECT THE AREA SUN NIGHT INTO
MON...BRINGING ANOTHER CHANCE OF PCPN TO THE AREA. DIFFERENCES IN
HOW AMPLIFIED THE TROUGH IS...ALONG WITH MOISTURE RETURN FROM THE
GULF...SO WILL LEAVE POPS AT SLIGHT/CHANCES.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT SLOWLY IMPROVING CONDITIONS THROUGH THE TAF PERIOD.
PREDOMINANT CONDITIONS THROUGH AT LEAST THE MORNING HOURS WILL BE
IFR AS LOW LEVELS ARE VERY MOIST. DRIZZLE/FREEZING DRIZZLE WILL BE
POSSIBLE AT ALL TAF SITES DURING THE PERIOD. THERE IS ABOVE NORMAL
UNCERTAINTY IN HOW LONG LOW VIS AND CIGS WILL STICK AROUND. THE BEST
CHANCE FOR IMPROVEMENTS WILL BE AT IWD LATE IN THE TAF PERIOD AS FLOW
BECOMES LESS FAVORABLE FOR POOR CONDITIONS. &&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO EARLY WED AS A
LOW PRESSURE TROUGH SLOWLY SLIDES ACROSS LK SUPERIOR. WINDS BECOME
MORE SOUTHERLY AS ANOTHER LO PRES SYSTEM DEVELOPING IN THE PLAINS
BEGINS TO LIFT TOWARD THE UPPER GREAT LAKES. SE WINDS AHEAD OF THIS
LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF ON WED. THE
MAIN HAZARD WILL BE AFTER THE LOW MOVES TOWARD QUEBEC ON THU...WHEN
NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING
WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE
SLOW APPROACH OF HI PRES. A STRONGER WSW FLOW WILL REDEVELOP ON SAT
AFTER THIS HI SHIFTS TO THE SE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ002-004>006-009>013-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...TITUS
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...SRF
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
403 AM CST TUE DEC 13 2011
.SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
&&
.AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 31 35 23 / 20 40 60 40
INL 29 24 33 16 / 10 20 40 40
BRD 33 31 34 22 / 10 50 50 30
HYR 36 32 36 28 / 10 40 70 60
ASX 36 32 37 28 / 20 30 60 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ038.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ006>009.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ001>004.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....TENTINGER
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 AM CST TUE DEC 13 2011
.SHORT TERM...TODAY THROUGH THURSDAY
342 AM CST TUE DEC 13 2011
FOCUS TODAY IS ON DENSE FOG ACROSS NORTH CENTRAL WISCONSIN THIS MORNING.
FORECAST CONCERNS THEN TURN TO STORM SYSTEM IMPACTING THE AREA
TONIGHT THROUGH THURSDAY MORNING.
CURRENT SURFACE OBSERVATIONS SHOW DENSE FOG ACROSS NORTH CENTRAL
WISCONSIN. A DENSE FOG ADVISORY HAS BEEN ISSUED FOR CLARK AND
TAYLOR COUNTIES THROUGH 9AM THIS MORNING. PATCHY FOG WAS REPORTED
ACROSS PORTIONS OF SOUTHEAST MINNESOTA THROUGH WEST CENTRAL
WISCONSIN. CURRENT WATER VAPOR IMAGERY SHOWED A POTENT UPPER LEVEL
TROUGH MOVING ACROSS THE SOUTHWEST...WITH MOISTURE STREAMING
NORTHWARD ACROSS THE SOUTHERN AND CENTRAL PLAINS.
CLOUDY SKIES CAN BE EXPECTED ACROSS THE AREA TODAY AS LOW LEVEL
MOISTURE REMAINS IN PLACE ACROSS THE REGION. AREAS OF FOG WILL
LINGER ACROSS WEST CENTRAL THROUGH NORTH CENTRAL WISCONSIN EARLY
THIS MORNING. LIGHT SOUTHEAST WINDS ARE EXPECTED TO DEVELOP LATER
THIS MORNING AND SHOULD ADVECT SLIGHTLY DRIER AIR INTO THE REGION
WITH FOG GRADUALLY DISSIPATING. BE ALERT FOR DENSE FOG THIS
MORNING ACROSS NORTH CENTRAL WISCONSIN...WHERE VISIBILITIES COULD
BE REDUCED TO AROUND ONE QUARTER OF A MILE AT TIMES. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE THE MID 30S ACROSS NORTH
CENTRAL WISCONSIN TO THE LOWER 40S ACROSS PORTIONS OF NORTHEAST
IOWA THROUGH SOUTHWEST WISCONSIN. AN UPPER LEVEL TROUGH WILL MOVE
FROM THE SOUTHWEST CONUS INTO THE SOUTHERN PLAINS TODAY...WITH
PRECIPITATION SPREADING ACROSS THE SOUTHERN/CENTRAL PLAINS. A WARM
FRONT CURRENTLY POSITIONED FROM SOUTHWEST KANSAS EAST INTO THE
OHIO RIVER VALLEY REGION WILL LIFT NORTHWARD THROUGH THE DAY TODAY.
THE WARM FRONT IS EXPECTED TO BE POSITIONED ACROSS SOUTHERN IOWA
INTO NORTHERN ILLINOIS BY THIS EVENING.
THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO THE FORECAST AREA LATE
TONIGHT INTO EARLY WEDNESDAY MORNING. LOOK FOR RAIN TO SPREAD ACROSS
THE AREA TONIGHT...POSSIBLY MIXING WITH SNOW ACROSS NORTH CENTRAL
AND CENTRAL WISCONSIN WHERE FORECAST SOUNDINGS SUPPORT SNOW BEFORE
THE WARM AIR ALOFT MOVES IN. TEMPERATURES WILL GRADUALLY WARM
OVERNIGHT AS THE WARM FRONT LIFTS NORTH ACROSS THE AREA. THE RAIN
WILL SPREAD INTO NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN DURING
THE EVENING HOURS...THEN SPREAD NORTHWARD AFTER MIDNIGHT. VERY
MOIST AIR WILL MOVE INTO THE AREA BEHIND THE WARM FRONT LATE
TONIGHT INTO WEDNESDAY MORNING...WITH PRECIPITABLE WATER VALUES
INCREASING TO AROUND 340 PERCENT OF NORMAL. FORECAST SOUNDINGS ARE
SHOWING ELEVATED CAPE ACROSS MUCH OF THE FORECAST AREA WEDNESDAY
MORNING INTO WEDNESDAY AFTERNOON. LIFTING FROM 780 MB YIELDS
AROUND 200 J/KG LATE WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON.
WOULD EXPECT TO SEE A FEW LIGHTING STRIKES THROUGH THE DAY ON
WEDNESDAY...SO HAVE ADDED THUNDER MENTION TO THE FORECAST.
DEEPENING ON HOW MUCH WARMING IS REALIZED WITHIN THE WARM
LAYER...COULD SEE SOME SMALL HAIL MAKE IT TO THE SURFACE IN ANY
CONVECTION THAT DEVELOPS. RAINFALL AMOUNTS ON WEDNESDAY WILL RANGE
FROM A QUARTER OF AN INCH ACROSS PORTIONS OF SOUTHEAST MINNESOTA
THROUGH NORTH CENTRAL WISCONSIN...TO AROUND THREE QUARTERS OF AN
INCH ACROSS MUCH OF NORTHEAST IOWA THROUGH SOUTHWEST WISCONSIN.
MODELS ARE SHOWING STRONG ISENTROPIC LIFT ON THE 280 THROUGH 315 K
SURFACE WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON...SO SHOULD
SEE RAINFALL ACROSS THE ENTIRE AREA THROUGH MUCH OF THE DAY. LOOK
FOR HIGH TEMPERATURES TO RANGE FROM THE UPPER 30S ACROSS NORTH
CENTRAL WISCONSIN TO THE MID TO UPPER 40S ACROSS NORTHEAST IOWA.
THE UPPER LEVEL TROUGH WILL LIFT INTO THE UPPER MISSISSIPPI RIVER
VALLEY WEDNESDAY EVENING. MODELS ARE SHOWING DIFFERENCES REGARDING
THE TRACK OF THE SURFACE LOW AS IT MOVES ACROSS THE REGION WEDNESDAY
EVENING. THE GFS TAKES THE LOW ACROSS NORTHEAST IOWA INTO NORTHEAST
WISCONSIN...WHILE THE NAM TAKES THE LOW ACROSS NORTHWEST IOWA AND
LIFTING IT NORTHEAST TO WESTERN LAKE SUPERIOR. IF THE NAM SOLUTION
HOLDS...PRECIPITATION WILL END ACROSS MUCH OF THE FORECAST AREA
EARLY WEDNESDAY EVENING. FORECAST SOUNDINGS SHOW DRIER AIR MOVING IN
ALOFT WEDNESDAY NIGHT AS THE LOW LIFTS NORTHEAST OF THE FORECAST
AREA AND A COLD FRONT MOVES IN FROM THE NORTHWEST. DEPENDING ON HOW
QUICKLY SURFACE TEMPERATURES COOL...COULD SEE A PERIOD OF FREEZING
DRIZZLE/DRIZZLE LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
RAIN SHOULD SWITCH OVER TO LIGHT SNOW OR POSSIBLY DRIZZLE/FREEZING
DRIZZLE AS COLDER AIR MOVES IN LATE IN THE NIGHT INTO THE EARLY
MORNING HOURS. STRONG COLD AIR ADVECTION WILL SET UP ACROSS THE
AREA EARLY ON THURSDAY BEHIND THE COLD FRONT. STRONG NORTHWEST
WINDS WILL DEVELOP EARLY ON THURSDAY....WITH SPEEDS OF 20 TO 25
MPH EXPECTED AND GUSTS TO AROUND 35 MPH POSSIBLE. IF DEEPER MIXING
IS REALIZED...A WIND ADVISORY MAY BE NEEDED ACROSS THE OPEN AREAS
OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. TEMPERATURES WILL FALL
THROUGH THE DAY ON THURSDAY. LOOK FOR HIGHS IN THE LOWER 30S EARLY
IN THE MORNING...WITH TEMPS FALLING INTO THE LOWER 20S BY LATE
AFTERNOON INTO THE EARLY EVENING. COOL HIGH PRESSURE WILL SETTLE
OVER THE AREA THURSDAY NIGHT WITH MOSTLY CLEAR SKIES EXPECTED.
LOOK FOR LOWS TO FALL INTO THE TEENS.
.LONG TERM...FRIDAY THROUGH MONDAY
342 AM CST TUE DEC 13 2011
13.00 MEDIUM RANGE MODELS IN REASONABLE AGREEMENT FRIDAY INTO
SATURDAY WITH COOL HIGH PRESSURE IN PLACE ACROSS THE REGION
PROVIDING QUIET CONDITIONS. LOOK FOR HIGHS ON FRIDAY AND SATURDAY TO
RANGE FROM THE UPPER 20S TO LOWER 30S...WITH LOWS IN THE TEENS
FRIDAY NIGHT...WARMING INTO THE 20S SATURDAY NIGHT. WARMER AIR IS
EXPECTED TO MOVE BACK INTO THE REGION SATURDAY NIGHT THROUGH
SUNDAY...WITH 850 MB TEMPERATURES WARMING TO AROUND 4 C. HIGHS ON
SUNDAY ARE EXPECTED TO CLIMB BACK INTO THE 30S. MODELS ARE SHOWING
DIFFERING SOLUTIONS ON SUNDAY NIGHT INTO MONDAY. THE GFS SHOWS AN
UPPER LEVEL LOW MOVING FROM THE FOUR CORNER REGION INTO THE CENTRAL
PLAINS DURING THIS TIME FRAME...THEN MOVING INTO THE UPPER MISSISSIPPI
RIVER VALLEY ON MONDAY. THE ECMWF KEEPS THIS SYSTEM WELL TO THE
SOUTH AND TAKES IT FROM SOUTHWEST INTO THE SOUTHERN PLAINS. CHOSE TO
GO WITH A MODEL CONSENSUS BLEND APPROACH FOR PRECIPITATION CHANCES
DURING THIS TIME FRAME...WITH A CHANCE OF SNOW LATE SUNDAY NIGHT
THROUGH MONDAY. THE SNOW MAY MIX WITH RAIN DURING THE DAY ON MONDAY.
WILL HAVE TO CLOSELY MONITOR THIS SYSTEM THE NEXT FEW MODEL RUNS.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1109 PM CST MON DEC 12 2011
BIG CONCERN FOR THE OVERNIGHT PERIOD IS WHETHER THE CEILINGS AND
VISIBILITY WILL GO TO IFR CONDITIONS. THE 13.03Z RUC AND 13.00Z
NAM BUFKIT SOUNDINGS SHOW A LARGE DRY WEDGE JUST ABOVE THE SURFACE
WITH SATURATION OCCURRING AGAIN BETWEEN 2 AND 3KT FEET. THIS IS
EXACTLY WHERE THE CEILINGS HAVE BEEN SETTING ALL NIGHT AND THE 00Z
KDVN AND KMPX SOUNDING SUPPORT THE EXISTENCE OF THIS DRY LAYER
OVER THE AREA. THAT WOULD ALSO EXPLAIN THE GENERAL LACK OF FOG
DESPITE THE RECENT PRECIPITATION AND HAVING SURFACE TEMP/DEW
POINT SPREADS OF 3 DEGREES OR LESS. THESE BUFKIT SOUNDINGS
SUGGESTS THIS DRY WEDGE WILL REMAIN IN PLACE PAST SUNRISE BEFORE
ERODING. CONFIDENCE ON THIS TIMING IS NOT HIGH SO HAVE BACKED OUT
OF IFR CONDITIONS FOR BOTH SITES BUT STILL INDICATE SOME FOG
FORMING TAKING VISIBILITIES DOWN TO MVFR WITH THE CEILING HOLDING
STEADY THROUGH THE NIGHT. WITH A VERY LIGHT FLOW TUESDAY...MAY NOT
BE MUCH CHANGE OTHER THAN THE LIGHT FOG DISSIPATING AS THE FLOW
SLOWLY STARTS TO INCREASE AHEAD OF THE NEXT SYSTEM. BOTH THE NAM
AND GFS SUGGEST SOME POTENTIAL FOR RAIN TO MOVE INTO BOTH TAF
SITES RIGHT AROUND 14.06Z TUESDAY OR SHORTLY AFTER. FOR NOW WILL
STAY WITH A DRY FORECAST THROUGH 14.06Z BUT NEXT SET OF FORECASTS
WILL HAVE TO INCLUDE THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
342 AM CST TUE DEC 13 2011
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1109 PM CST MON DEC 12 2011
.SHORT TERM...TONIGHT THROUGH THURSDAY
230 PM CST MON DEC 12 2011
FORECAST CONCERNS FOCUS ON THE NEXT WEATHER SYSTEM TO IMPACT THE
AREA TUE NIGHT-WED NIGHT...LOOKING MOSTLY RAIN.
TONIGHT...UPPER LEVEL SHORTWAVE TROUGH CONTINUES OFF TO THE
EAST...WITH SOME LINGERING ISENTROPIC UPGLIDE THROUGH THE LOW
SATURATION THIS EVENING. BUFKIT SOUNDINGS POINT TO SOME SHALLOWING
OF THE MOISTURE...WITH NO ICE IN THE CLOUD. DRIZZLE SHOULD BE THE
PCPN TYPE FOR WHATEVER FALLS. WITH THE BROADSCALE THERMODYNAMIC LIFT
EXITING OVERNIGHT...BELIEVE THE THREAT FOR SOME LIGHT DRIZZLE SHOULD
TOO. SFC TEMPS LOOK TO STAY ABOVE FREEZING...AND DON/T ANTICIPATE
MUCH/IF ANY FREEZING DRIZZLE AT THIS TIME. THAT SAID...SOME
LOCATIONS IN COLDER DRAINAGE AREAS COULD STILL HAVE A MINOR THREAT
OF ICING THIS EVENING.
UPPER LEVEL TROUGH CURRENTLY OVER THE WEST COAST IS PROGGED TO LIFT
NORTHEAST ACROSS THE PLAINS TUE NIGHT/WED...MOVING OVER THE UPPER
MISSISSIPPI RIVER AS AN OPEN WAVE WED NIGHT. MEANWHILE SHORTWAVE
TROUGH IN THE NORTHERN STREAM WILL SPIN OVER THE NORTHERN GREAT
LAKES EARLY THU. THE MODELS HAVE HAD A VARIETY OF SOLUTIONS OVER THE
PAST FEW DAYS...LOWERING FORECAST CONFIDENCE IN TIMING/POSITIONING.
THIS GO AROUND THOUGH THE GFS/EC SOLUTIONS ARE MUCH CLOSER WITH THE
MAIN FORECAST FEATURES. THE NAM REMAINS QUICK...WITH A STRONGER
NORTHERN SHORTWAVE LIKELY RESULTING IN ITS SFC LOW PULLING/DEEPENING
FARTHER NORTH AS A RESULT. OVERALL THOUGH...NOT SURE THE DIFFERENCES
WILL HAVE A BIG IMPACT ON THE SENSIBLE WEATHER...OTHER THAN
START/END TIMES...AS ALL POINT TO RAIN BEING THE PREDOMINANT PCPN
TYPE DURING THE LIFE OF THE EVENT.
OUT AHEAD OF THE HEART OF THIS NEXT WEATHER SYSTEM LOW LEVEL WARM
AIR ADVECTION/ISENTROPIC UPGLIDE WILL SPREAD ACROSS THE REGION FROM
THE SOUTH TUE NIGHT...WITH THE NOSE OF THE 850 MB MOISTURE TRANSPORT
POINTING INTO SOUTHERN WI BY 12Z WED. MID LEVEL FRONTOGENETIC
RESPONSE /700-500 MB/ OVERNIGHT. EXPECT A BLOSSOMING/ADVECTING AREA
OF PRECIPITATION TO SPREAD ACROSS THE AREA OVERNIGHT TUE AS A
RESULT. COULD BE A SMALL BREAK/LESSENING IN AREAL EXTENT OF PCPN
LATER WED MORNING...BUT THIS SHOULD FILL BACK IN AS THE SHORTWAVE
AND SFC LOW MOVE INTO SOUTHERN WI WED EVENING. GOOD SLOPING
FRONTOGENETIC RESPONSE NORTHWEST OF THE LOW...BUT AGAIN...MOSTLY
CONFINED TO THE MID LEVELS OF THE ATMOSPHERE.
AS MENTIONED EARLIER...IT LOOKS LIKE A RAIN EVENT FOR THE REGION.
NORTHWEST-SOUTHEAST RUNNING TIME/HEIGHT X-SECTIONS AND BUFKIT
SOUNDINGS POINT TO AN INCREASING WARM LAYER FROM AROUND 800 MB TO
THE SFC FROM 00Z WED THROUGH 06Z THU. THIS DEEP WARM LAYER WILL
RESULT IN RAIN. SOME HINTS THAT LOCATIONS TO THE NORTH/NORTHWEST
COULD START OUT AS A RAIN OR RAIN/SNOW MIX...BUT DON/T THINK THIS
WOULD LAST LONG. ON THE BACKSIDE...IN THE DEFORMATION REGION AS THE
STORM SYSTEM EXITS TO THE EAST...COLD AIR WILL BE RETURNING. A
CHANGE OVER TO RAIN/SNOW OR SNOW COULD OCCUR WED NIGHT BEFORE ALL
THE PCPN EXITS NORTHEAST...MOSTLY FOR LOCATIONS ALONG AND NORTH OF
AN AUSTIN TO BLACK RIVER FALLS LINE. THERE COULD BE SOME MINOR
ACCUMULATIONS AT THIS TIME.
THE SFC PRESSURE GRADIENT TIGHTENS POST THE SYSTEM ON THU...WITH A
TROP FOLD DOWN TO 800 MB VIA THE GFS AND EC. VERT WIND PROFILE
UNI-DIRECTIONAL THROUGH A SIZABLE PORTION OF THE LOWER
ATMOSPHERE...AND RH FIELDS POINT TO QUICK CLEARING TO THE WEST. THU
SHOULD BE A RATHER WINDY DAY...AND SOME SIGNALS SUGGEST THAT A WIND
ADV COULD BE NEEDED FOR THE WINDER/OPEN AREAS OF SOUTHEAST MN AND
NORTHEAST IA. SOMETHING TO WATCH.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
230 PM CST MON DEC 12 2011
HIGH PRESSURE WORKS IN FOR FRI/SAT...WITH DRY CONDITIONS FAVORED AS
A RESULT. MODEL DIFFERENCES CREEP UP AGAIN FOR SUN/MON THOUGH AS THE
EC WOULD SLIDE AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE NORTHERN
GREAT LAKES SUN...WHILE THE GFS IS MORE ACTIVE IN THE SOUTHERN
STREAM...BRINGING A SHORTWAVE UP FROM THE PLAINS SUN NIGHT/MON.
CONFIDENCE LOW IN THE DETAILS IN THIS PERIOD WITH SOME MARKEDLY
DIFFERENT SOLUTIONS. WILL LEAN ON THE CONSENSUS FOR NOW.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1109 PM CST MON DEC 12 2011
BIG CONCERN FOR THE OVERNIGHT PERIOD IS WHETHER THE CEILINGS AND
VISIBILITY WILL GO TO IFR CONDITIONS. THE 13.03Z RUC AND 13.00Z
NAM BUFKIT SOUNDINGS SHOW A LARGE DRY WEDGE JUST ABOVE THE SURFACE
WITH SATURATION OCCURRING AGAIN BETWEEN 2 AND 3KT FEET. THIS IS
EXACTLY WHERE THE CEILINGS HAVE BEEN SETTING ALL NIGHT AND THE 00Z
KDVN AND KMPX SOUNDING SUPPORT THE EXISTENCE OF THIS DRY LAYER
OVER THE AREA. THAT WOULD ALSO EXPLAIN THE GENERAL LACK OF FOG
DESPITE THE RECENT PRECIPITATION AND HAVING SURFACE TEMP/DEW
POINT SPREADS OF 3 DEGREES OR LESS. THESE BUFKIT SOUNDINGS
SUGGESTS THIS DRY WEDGE WILL REMAIN IN PLACE PAST SUNRISE BEFORE
ERODING. CONFIDENCE ON THIS TIMING IS NOT HIGH SO HAVE BACKED OUT
OF IFR CONDITIONS FOR BOTH SITES BUT STILL INDICATE SOME FOG
FORMING TAKING VISIBILITIES DOWN TO MVFR WITH THE CEILING HOLDING
STEADY THROUGH THE NIGHT. WITH A VERY LIGHT FLOW TUESDAY...MAY NOT
BE MUCH CHANGE OTHER THAN THE LIGHT FOG DISSIPATING AS THE FLOW
SLOWLY STARTS TO INCREASE AHEAD OF THE NEXT SYSTEM. BOTH THE NAM
AND GFS SUGGEST SOME POTENTIAL FOR RAIN TO MOVE INTO BOTH TAF
SITES RIGHT AROUND 14.06Z TUESDAY OR SHORTLY AFTER. FOR NOW WILL
STAY WITH A DRY FORECAST THROUGH 14.06Z BUT NEXT SET OF FORECASTS
WILL HAVE TO INCLUDE THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST MON DEC 12 2011
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... RIECK
LONG TERM.... RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
233 AM MST TUE DEC 13 2011
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
.LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
.AVIATION...06Z TAF ISSUANCE...LIFR OR LOWER CONDITIONS IN STRATUS
AND FOG GRADUALLY SPREADING WESTWARD THROUGH THE WESTERN NEBRASKA
PANHANDLE PER SURFACE AND SATELLITE OBSERVATIONS. THIS DETERIORATING
TREND WILL CONTINUE OVERNIGHT. 00Z NAM AND SREF HAVE BACKED OFF ON
MVFR TO IFR CONDITIONS ACROSS SOUTHEAST WYOMING...BUT HRRR BRINGS
IN IFR TO A LUSK-PINE BLUFFS LINE AFTER 09Z. HAVE ADDED A TEMPO
GROUP FOR LOW END MVFR AT CHEYENNE BETWEEN 10Z AND 14Z. MODELS
MAINTAIN THESE IFR-LIFR CONDITIONS FOR THE PANHANDLE TERMINALS
THROUGH AT LEAST 18Z WHEN CEILINGS AND VISIBILITIES IMPROVE TO
MVFR. WINDS WILL REMAIN LIGHT...GENERALLY LESS THAN 10 KT...DURING
THE FORECAST PERIOD.
&&
.FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION/FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1044 PM MST MON DEC 12 2011
.AVIATION...06Z TAF ISSUANCE...LIFR OR LOWER CONDITIONS IN STRATUS
AND FOG GRADUALLY SPREADING WESTWARD THROUGH THE WESTERN NEBRASKA
PANHANDLE PER SURFACE AND SATELLITE OBSERVATIONS. THIS DETERIORATING
TREND WILL CONTINUE OVERNIGHT. 00Z NAM AND SREF HAVE BACKED OFF ON
MVFR TO IFR CONDITIONS ACROSS SOUTHEAST WYOMING...BUT HRRR BRINGS
IN IFR TO A LUSK-PINE BLUFFS LINE AFTER 09Z. HAVE ADDED A TEMPO
GROUP FOR LOW END MVFR AT CHEYENNE BETWEEN 10Z AND 14Z. MODELS
MAINTAIN THESE IFR-LIFR CONDITIONS FOR THE PANHANDLE TERMINALS
THROUGH AT LEAST 18Z WHEN CEILINGS AND VISIBILITIES IMPROVE TO
MVFR. WINDS WILL REMAIN LIGHT...GENERALLY LESS THAN 10 KT...DURING
THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 904 PM MST MON DEC 12 2011/
UPDATE...EVENING WATER VAPOR IMAGERY SHOWED THE UPPER LOW PRESSURE
SYSTEM SLIDING SOUTH OFF THE SOUTH CENTRAL CALIFORNIA COAST WITH
PACIFIC MOISTURE STREAMING NORTH-NORTHEAST INTO THE CENTRAL/SOUTHERN
ROCKIES AND GREAT BASIN. THE REGIONAL SURFACE ANALYSIS PLACED A
WEAK STATIONARY FRONT FROM THE SOUTHERN LARAMIE RANGE INTO EASTERN
COLORADO AND THEN NORTHEAST INTO SOUTHERN NEBRASKA. WEAK MOIST
SOUTHEASTERLY FLOW OVERRUNNING THE BOUNDARY WAS RESULTING IN AN
EXTENSIVE LOW STRATUS DECK FROM WESTERN SOUTH DAKOTA INTO THE
WESTERN NEBRASKA PANHANDLE. THE 01Z HRRR MODEL OUTPUT INDICATES
GRADUAL WESTWARD EXPANSION AND LOWERING OF THE STRATUS WITH
AREAS OF FREEZING FOG AFFECTING THE LEE OF THE LARAMIE RANGE AND
HIGH PLAINS OF SOUTHEAST WYOMING LATER TONIGHT. ALSO...BUFKIT AND
MODEL SOUNDING DATA SUGGESTS A GRADUAL DEEPENING OF A SUBFREEZING
LAYER JUST BELOW A PRONOUNCED LOW LEVEL INVERSION ACROSS THE
SOUTHEAST 1/4 OF THE CWA BY 12Z TUESDAY. HAVE UPDATED THE WEATHER
GRIDS TO INSERT PATCHY FREEZING DRIZZLE FOR THE SOUTHERN PORTIONS
OF THE WESTERN PANHANDLE TUESDAY MORNING. NOT EXPECTING ANY
ACCUMULATIONS OR IMPACTS AT THIS TIME. THE FOG WILL BECOME LOCALLY
DENSE LATER TONIGHT...ESPECIALLY FOR THE WESTERN PANHANDLE WHERE
VISIBILITIES MAY DROP TO 1/2 MILE OR LESS AT TIMES. ONE TO THREE
MILE VISIBILITY WILL BE POSSIBLE OVER SOUTHEAST WYOMING.
PREV DISCUSSION... /ISSUED 523 PM MST MON DEC 12 2011/
AVIATION...00Z TAF ISSUANCE...LIFR CONDITIONS PERSIST AT CHADRON.
THESE LOW CONDITIONS WILL GRADUALLY OVERSPREAD THE REMAINDER OF THE
PANHANDLE AND EXTREME SOUTHEAST WYOMING TONIGHT PER THE LATEST
HRRR MODEL OUTPUT. THE NAM SHOWS SOME MVFR TO IFR CONDITIONS
DEVELOPING ACROSS CARBON COUNTY OVERNIGHT. THE LOW CEILINGS
AND VISIBILITIES WILL LIKELY LINGER THROUGH LATE TUESDAY MORNING
BEFORE IMPROVING TO MVFR OR BETTER. LIGHT SOUTH TO SOUTHEAST
WINDS TONIGHT WILL VEER TO SOUTHWEST TUESDAY MORNING.
PREV DISCUSSION... /ISSUED 235 PM MST MON DEC 12 2011/
SHORT TERM...TONIGHT THROUGH THURSDAY...
FOR THIS FORECAST THE CURRENT UPPER LOW CURRENTLY OVER CENTRAL
CALIFORNIA WILL MOVE NORTHEAST AND ACROSS THE ROCKIES. THE FEATURE
WILL SLOWLY FILL AS IT MOVES NORTHEAST AND THE TROUGH AXIS WILL BE
EAST OF THE CWA LATE WEDNESDAY AFTERNOON OR WEDNESDAY EVENING.
DURING THAT SAME TIME...SURFACE UPSLOPE WIND FLOW WILL PERSIST OVER
MUCH OF THE CWA. AS THE PLAINS SURFACE HIGH MOVES FURTHER EAST...
THE BOUNDARY LAYER WINDS WILL TURN TO MORE SOUTHWEST TUESDAY
AFTERNOON. PRIOR TO THAT...WIDESPREAD LOW CLOUDS AND FOG WILL
SPREAD AND DEVELOP OVER MUCH OF THE CWA BY 06Z. CURRENT AND
FORECAST RAOBS INDICATE THAT THE CLOUD DEPTH WILL BE BETWEEN 1000
AND 1500 FEET WHICH SHOULD NOT BE ENOUGH FOR FLURRIES OF FREEZING
DRIZZLE. THE SOUTHWEST BOUNDARY LAYER WINDS TUESDAY AFTERNOON
SHOULD HELP DISSIPATE THE LOWER CLOUDS AND FOG OVER THE EAST PART OF
THE CWA. WITH THE SHORTWAVE TROUGH PASSAGE ON WEDNESDAY
AFTERNOON...NORTHWEST SURFACE WINDS WILL INCREASE WITH SOME GUSTS
BETWEEN 30 AND 40 MPH. THOSE WINDS WILL PERSIST OVER AREAS ALONG
AND EAST OF THE LARAMIE RANGE THROUGH THURSDAY. MOST OF ANY
PRECIPITATION WILL OCCUR OVER AND NEAR THE SNOWY AND SIERRA MADRE
RANGES THROUGH THURSDAY AND WILL BE IN THE FORM OF LIGHT SNOW OR
FLURRIES. THERE MAY BE ENOUGH LIFT AS WELL OVER THE SOUTHEAST
QUARTER OF THE CWA FOR LATER TONIGHT AND WEDNESDAY MAINLY DUE TO THE
LOCATION OF THE 300 MB JET...HOWEVER MOISTURE DEPTH WILL BE
LACKING.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
12/12Z GFS AND ECMWF SIMILAR SYNOPTICALLY AT 500 MB...THUS MODERATE
TO HIGH CONFIDENCE IN THEIR RESPECTIVE SOLUTIONS.
WEDNESDAY NIGHT/THURSDAY...OUR COUNTIES WILL BE IN BETWEEN SYSTEMS...
THUS DRY. LOOKS LIKE ENOUGH MID/HIGH CLOUDS IN ADVANCE OF SHORTWAVE
TROUGH ALOFT OVER THE GREAT BASIN STATES TO KEEP OUR HIGH
TEMPERATURES IN THE 30S.
FRIDAY...NEXT COLD FRONT PLOWS ACROSS ALONG WITH CHANCES FOR SNOW...
THOUGH SNOW COVERAGE AND INTENSITY WILL BE LIMITED AS THE ENERGY
WITH THE SHORTWAVE TROUGH ALOFT IS SPLIT AND SHEARED WITH MOST OF
THE ENERGY REMAINING SOUTH OF WYOMING.
SATURDAY...CUTOFF LOW ALOFT WILL LIE TO OUR SOUTH WITH PRECIPITATION
OVER ARIZONA AND NEW MEXICO. DRY ACROSS OUR COUNTIES WITH SURFACE
LEE TROUGHING.
SUNDAY...TROUGH ALOFT OPENS UP AND MOVES ACROSS COLORADO AND NEW
MEXICO WITH PRECIPITATION TO THE SOUTH OF WYOMING AND NEBRASKA. LACK
OF CLOUD COVER ALONG WITH 1000-500 MB THICKNESSES NEAR 5490 METERS
WILL HELP HIGH TEMPERATURES REACH THE 30S AND MID 40S.
MONDAY...NEXT COLD FRONT MOVES ACROSS OUR COUNTIES WITH HIGH
TEMPERATURES BACK IN THE 20S AND 30S. LOOKS LIKE ENOUGH LOW AND MID
LEVEL MOISTURE FOR SCATTERED COVERAGE OF SNOW ACROSS THE NORTHERN
LARAMIE...SNOWY AND SIERRA MADRE RANGES...DRY ELSEWHERE.
FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE CWA THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL BE NEAR NORMAL OVERALL AND...OUTSIDE OF
WEDNESDAY...WINDS WILL BE FAIRLY LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...WEILAND
LONG TERM...RUBIN
AVIATION/UPDATE...JAMSKI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
940 AM EST TUE DEC 13 2011
.DISCUSSION...
MUCH DRIER DAY ACROSS EAST CENTRAL FLORIDA THIS MORNING WITH ONLY A
FEW LIGHT SHOWERS GENERATING OVER THE ATLANTIC WATERS AND
DIMINISHING AS THEY MOVE INTO THE COAST. LARGE LOW LEVEL HIGH
PRESSURE ACROSS THE EASTERN US WILL CONTINUE TO DRIVE THE WEATHER
ACROSS THE SOUTHEAST AS IT GENERATES A DEEP AND STEADY NORTHEASTERLY
FLOW. A STRONG UPPER LEVEL BUILDING INTO THE GULF OF MEXICO WILL
HAMPER ANY DEEPER CONVECTION FROM DEVELOPING AS THE SUBSIDENCE
INVERSION DEEPENS AROUND 700MB AND THE NW FLOW ALOFT BRINGS IN DRIER
AIR.
WILL KEEP THE MENTION OF ISOLATED LIGHT SHOWERS ALONG THE COAST
THROUGH EARLY AFTERNOON AND SPRINKLES OVER THE INTERIOR FOR THE WEAK
ACTIVITY THAT SURVIVES TO MAKE IT INLAND. BREEZY ONSHORE FLOW
WILL MAINTAIN A STRONG MARITIME INFLUENCE ACRS THE AREA...TEMPS WILL
CONTINUE ABV CLIMO WITH MAXES IN THE M/U70S...WITH A FEW LOCATIONS
POSSIBLY REACHING 80 WITH FEWER CLOUDS AND MORE SUNSHINE.
&&
.AVIATION...LINGERING IFR CIGS AND MVFR VSBYS IN FOG/STRATUS NORTH
AND WEST OF I-4 SLOWLY ERODING THROUGH 16Z. OTHERWISE...PREVAILING
VFR ALL SITES WITH CIGS BTWN FL040-060. BRIEF MVFR CIGS IN ISOLD
SHRA BRUSHING THE COAST AND OVER LCL ATLC. NE SFC WND G22-25KTS THRU
13/23Z.
&&
.MARINE...WINDS AT BUOY 41009 CONTINUE FROM THE NE TO OCCASIONALLY
ENE AT 15-20KTS THIS MORNING AS THE LARGE SFC HIGH OVER THE EASTERN
US CONTINUES TO GENERATE A MODERATE TO FRESH BREEZE ACROSS THE LOCAL
ATLC. THOUGH WINDS AT THE BUOY ARE SLIGHTLY BELOW SCA
CRITERIA...OBSERVATIONS JUST OUTSIDE OF OUR WATERS ARE RUNNING
CLOSER TO 20KTS WITH RUC ANALYSIS ALSO SHOWING THE SAME. WILL KEEP
THE FULL SCA UP THROUGH LATE TONIGHT TRANSITIONING TO A SCA FOR SEAS
THEREAFTER. THE LONG NE FETCH OVER THE WEST ATLC WILL CONTINUE TO
PUSH A LARGE SWELL INTO THE E FL COAST. SEAS 6-8FT NEARSHORE AND
8-10FT OFFSHORE THRU DAYBREAK WED. WAVE PDS WILL OPEN UP AS THE
WINDS DIMINISH...INCREASING FROM 8-9SEC TODAY TO 9-10SEC TONIGHT.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST WEDNESDAY FOR COASTAL
WATERS FROM FLAGLER BEACH TO JUPITER INLET OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 AM WEDNESDAY TO
7 AM EST THURSDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO
JUPITER INLET OUT 60 NM.
&&
$$
SHORT TERM/AVIATION...MOSES
LONG TERM/IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1029 AM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE ACROSS THE AREA TODAY, KEEPING THE
AREA DRY AND TEMPERATURES SEASONABLE. A WARM FRONT WILL LIFT INTO
THE AREA ON WEDNESDAY AND BRING THE CHANCE OF SHOWERS. SHOWERS
WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD FRONT CROSSES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
15Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO INCREASE HIGH
TEMPS TODAY 2-3 DEGREES. IN ADDITION, PRECIPITATION NEAR DAWN
TOMORROW HAS BEEN CHANGED FROM A MIX OF RAIN AND SNOW TO ALL RAIN.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW WITH 700MB MOISTURE ADVECTING
INTO THE AREA. THIS HAS ALLOWED FOR INCREASING CLOUDINESS AS THE
MID-DECK MOVES INTO THE AREA. AT THE SURFACE, A 1031MB HIGH IS
CENTERED ACROSS OHIO.
TODAY...THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD INTO WESTERN
PENNSYLVANIA. THIS WILL ALLOW FOR A DRY DAY. 700MB MOISTURE
ADVECTING ACROSS THE AREA WILL ALLOW FOR SKY COVERAGE INCREASING
TO MOSTLY CLOUDY INTO THE AFTERNOON. WEAK WARM AIR ADVECTION WILL
OCCUR TODAY WITH 850 TEMPS WARMING TO 0-2C ACROSS THE AREA. WITH
THIS IN MIND, HIGH TEMPS ARE A MAV/MET BLEND, RANGING FROM THE
UPPER 40S ACROSS NORTH-CENTRAL WV AND EASTERN OHIO TO THE LOWER
40S ACROSS THE EASTERN RIDGES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WARM FRONT WILL PASS THROUGH WEDNESDAY MORNING. THERE ARE STILL
DISCREPANCIES BETWEEN OP MODELS ON THE AMOUNT OF PRECIPITATION AND
ITS EASTWARD EXTENT WITH THE FRONT. A COMPROMISE OF THE SREF, NAM
AND NMM-WRF, INDICATES THAT MOST OF THE RAIN CHANCE WILL BE OVER
OHIO AND EVENTUALLY NORTHERN PA.
RECENT OPERATIONAL MODEL RUNS INDICATE A WARMING LOW- LEVEL
THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING) ALLOWING FOR
ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH SURFACE TEMPS
A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE LEANED AGAINST A
MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR ALOFT PREVENTING
DENDRITIC GROWTH AND SATURATION LIMITED TO THE LOWER LEVELS.
THE WARM FRONT PASSES TO THE NORTH WED AFTERNOON. THIS WILL PUT
THE AREA IN THE WARM SECTOR AND ALSO PROVIDE A BREAK IN THE RAIN
AHEAD OF THE APPROACHING COLD FRONT.
COLD FRONT WILL MOVE THROUGH LATE THURSDAY. IT LOOKS LIKE A
WIDESPREAD RAIN EVENT FOR THE AREA, BEGINNING THU MORNING AND
CONTINUING INTO THE EVENING HOURS. STRONG MID-LEVEL JET WILL PUMP
PLENTY OF MOISTURE INTO THE REGION AHEAD OF THE SFC FRONT.
A STRONG SOUTHERLY LL FLOW WILL PUSH TEMPS WILL ABOVE NORMAL ON
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BRIEF PERIOD OF LES IS POSSIBLE LATE THU/EARLY FRIDAY WITH THE
STRONG CAA BEHIND THE FRONT.
A SFC WAVE, OVER THE SE US, WILL DEVELOP ALONG THE COLD FRONT
FRIDAY. LATEST MODEL DATA IS KEEPING THIS WAVE SOUTH OF THE AREA.
HOWEVER, IT IS POSSIBLE THAT SOUTHERN LOCATIONS COULD SEE SOME
LIGHT PRECIP FRIDAY NIGHT.
HIGH PRESSURE WILL BUILD IN, KEEPING THE REMAINDER OF THE LONG
TERM DRY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS, WITH NO LOWER THAN ALTOCUMULUS CEILINGS, THROUGH
TONIGHT.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
DURING DAYTIME WEDNESDAY, A PASSING BAND OF WARM FRONTAL SHOWERS
WITH SHORT-LIVED RESTRICTIONS POSSIBLE. THURSDAY INTO THURSDAY
NIGHT, A WIDER BAND OF COLD FRONTAL SHOWERS WITH RESTRICTIONS MORE
LIKELY. FRIDAY AND SATURDAY, VFR PREVALENT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
557 AM CST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE...
LIFR/IFR CIGS AND VSBYS ACROSS THE REGION THIS MORNING WILL
IMPROVE SLIGHTLY BY THE LATE MORNING...WITH -FZDZ AROUND DLH AND
HIB TERMINALS. CIGS COULD POSSIBLY LIFT TO LOW-END MVFR...BUT WILL
LOWER AGAIN BY 00Z TO IFR AND POSSIBLY LIFR LATER IN THE EVENING
AND THROUGH THE OVERNIGHT. WILL SEE A CHANCE OF -FZDZ AGAIN THIS
EVENING AS COLD AIR REMAINS IN PLACE BUT A SURGE OF LOW LEVEL
MOISTURE GETS PUMPED INTO THE REGION FROM THE SOUTH. ENOUGH WARM
AIR AROUND BRD WILL KEEP PRECIP RAIN AND/OR SNOW. PATCHY IFR FOG
WILL ALSO RETURN AGAIN TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 403 AM CST TUE DEC 13 2011/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 31 35 23 / 20 40 60 40
INL 29 24 33 16 / 10 20 40 40
BRD 33 31 34 22 / 10 50 50 30
HYR 36 32 36 28 / 10 40 70 60
ASX 36 32 37 28 / 20 30 60 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ038.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ006>009.
FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR WIZ001>004.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....TENTINGER
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
609 AM CST TUE DEC 13 2011
.SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER LONG/CHALLENGING
NIGHT...MOSTLY SPENT FINE TUNING HOURLY SURFACE TEMPERATURE
TRENDS DURING THE NEXT 12-18 HOURS...AND RESULTANT PRECIP TYPE
FOR THE ONGOING HEADLINES. LOCALLY DENSE FOG IS ALSO ADDING TO THE
ONGOING FUN.
THE SHORT STORY FOR TODAY IS THAT THE INHERITED WINTER WEATHER
ADVISORIES FOR LIGHT ICING/LIGHT FREEZING RAIN WERE LEFT LARGELY
UNCHANGED. ONLY TWEAKS WERE TO ADD FILLMORE COUNTY TO THE SEGMENT
THAT EXPIRES AT NOON...AND TO DROP ROOKS COUNTY GIVEN THAT NEARBY
AUTOMATED OBS CONFIRM THAT TEMPS IN THAT AREA ARE GENERALLY 33-37
DEGREES...AND SHOULDN/T DROP ANY FARTHER. OTHER COUNTIES ON THE
EXTREME SOUTHERN EDGE SUCH AS PHILLIPS/SMITH ARE LIKELY MARGINAL
AS WELL...BUT AT LEAST NORTHERN EDGES COULD PICK UP SOME LIGHT
FREEZING DRIZZLE AND WANTED TO KEEP THEM IN. AS
MENTIONED...LOCALLY DENSE TO NEAR-DENSE ALSO CONTINUES TO DEVELOP
ACROSS PARTS OF THE CWA...AND FORESEE THIS BECOMING MORE AND MORE
OF AN ISSUE DURING THE NEXT SEVERAL HOURS. ISSUED A STAND-ALONE
DENSE FOG ADVISORY FOR ROOKS COUNTY KS...BUT OPTED TO KEEP IT
SIMPLE FOR THE MAJORITY OF THE CWA AND INCLUDE FOG HAZARDS IN THE
TEXT OF THE WINTER WEATHER ADVISORIES. THE HANDFUL OF COUNTIES IN
THE SOUTHERN CWA STILL UNDER NO HEADLINE MAY ULTIMATELY NEED ADDED
TO A DENSE FOG HEADLINE IF THINGS WORSEN...BUT AT LEAST FOR NOW
THESE COUNTIES SEEM TO HAVE VISIBILITIES SAFELY ABOVE ADVISORY
CRITERIA.
SO...FOR THE MOST PART THINGS STARTING TO UNFOLD AS
EXPECTED...WITH AT LEAST PATCHY AREAS OF LIGHT DRIZZLE/FREEZING
DRIZZLE GETTING UNDERWAY PER RADAR RETURNS AND GROUND TRUTH HERE
AT THE WFO. HOWEVER...AM NOT AWARE OF ANY SIGNIFICANT IMPACTS YET
AT THIS TIME. MOVING FORWARD INTO THE DAY...CONFIDENCE IN SEEING
WIDESPREAD MEASURABLE PRECIP HAS WANED FROM 24 HOURS AGO GIVEN
LATEST TRENDS OF RUC/NAM/HRRR KEEPING MOST LEGITIMATE RAIN SOUTH
OF THE CWA. STILL...INCREASING LOW LEVEL ISENTROPIC LIFT SHOULD BE
MORE THAN SUFFICIENT FOR CONTINUED DEVELOPMENT OF FOG AND AT LEAST
TRACE DRIZZLE/FREEZING DRIZZLE FOR SEVERAL HOURS IN MOST AREAS.
TOTAL ICE ACCUMULATIONS WITHIN THE ADVISORY AREAS HAVE BEEN
TRIMMED A BIT...NOW RANGING FROM A TRACE ALONG THE SOUTHERN FRINGE
TO MAYBE 5 HUNDREDTHS OF AN INCH OR SO IN NORTHWEST COUNTIES.
SPENT A LOT OF TIME FINE TUNING SURFACE TEMP TRENDS...LEANING
HEAVILY ON THE RUC AND HOURLY GFS LAMP GUIDANCE. TRENDS ON THE
GRADUAL SOUTH TO NORTH WARMING ABOVE FREEZING HAVEN/T CHANGED MUCH
FROM PREVIOUS THINKING...AND AS A RESULT SAW NO REASON TO CHANGE
THE CURRENT BREAKDOWN OF THE WINTER WEATHER ADVISORY...WITH
SEVERAL COUNTIES SOUTHEAST OF A FULLERTON TO ALMA LINE LIKELY DONE
WITH ANY ICING THREAT BY NOON AT THE LATEST...WHILE NORTHWEST
COUNTIES REMAIN UNDER THE GUN WELL INTO THE AFTERNOON. AGAIN...NOT
LOOKING AT MUCH ICE ACCUMULATION..ESPECIALLY MEASURABLE...BUT
EASILY ENOUGH TO CAUSE PROBLEMS ON UNTREATED SURFACES.
AS FOR DENSE FOG/POTENTIALLY DENSE FOG...COULD EASILY FORESEE
ISSUES LASTING WELL INTO THE OVERNIGHT HOURS...AND WILL DEFER TO
DAY SHIFT TO POSSIBLY ISSUE/EXTEND FOG HEADLINES AS NEW TRENDS
EMERGE. FOR NOW...WANTED AS MUCH FOCUS AS POSSIBLE TO BE ON LIGHT
ICING CONCERNS. DIDN/T CHANGE HIGH TEMPS TODAY MUCH...AIMING FOR A
GRADIENT FROM LOW-MID 30S NORTHWEST TO LOW-MID 40S SOUTHEAST.
BETTER CHANCES FOR LEGITIMATE MEASURABLE RAIN ARRIVES TONIGHT AS
PRIMARY MID LEVEL SHORTWAVE APPROACHES FROM NEW MEXICO...AND UPPER
JET DYNAMICS/DIFFLUENCE INCREASE. KEPT POPS HIGH
TONIGHT...ESPECIALLY ACROSS THE SOUTHEAST 1/2 OR SO WITH 70-90
PERCENTS. ALTHOUGH NOT EXPECTING WIDESPREAD LIGHTNING STRIKES...AT
LEAST 100-200 J/KG MUCAPE APPEARS SUFFICIENT FOR AT LEAST ISOLATED
THUNDERSTORMS...AND LEFT THIS MENTION INTACT ACROSS GENERALLY THE
SOUTHEAST 1/2 OF THE CWA. PRONOUNCED CONTINUED LOW LEVEL WARM AIR
ADVECTION SHOULD ALLOW TEMPS TO SLOWLY RISE OVERNIGHT...AND ONLY
THE EXTREME NORTHWEST FRINGES OF THE CWA SHOULD REGISTER TEMPS AT
OR BELOW FREEZING FOR A FEW HOURS AFTER SUNSET. UNLESS SOMETHING
LINGERS FOR A FEW HOURS FAR NORTHWEST...ICING ISSUES SHOULD BE LARGELY
OVER BY DARK.
WEDNESDAY...THE 00Z ECMWF/GFS ARE IN DECENT AGREEMENT TRACKING THE
MAIN SHORTWAVE DIRECTLY ACROSS THE PLAINS...WITH A ROUGHLY 1006MB
SFC LOW CENTERED OVER NORTH CENTRAL KS AT 18Z BEFORE ZIPPING
NORTHEAST. A MID LEVEL DRY SLOT COULD BRING PRECIP TO A FAIRLY
EARLY END ESPECIALLY IN SOUTHWEST ZONES...AND HAVE TRENDED POPS
DOWN ACCORDINGLY DURING THE DAY. WHILE THUNDER WAS NOT INCLUDED
FOR THE DAYTIME HOURS...COULD SEE SOME INSTABILITY LURKING IN
PARTS OF THE AREA...AND A FEW RUMBLES NOT OUT OF THE QUESTION.
HAVE QUITE A HIGH TEMP GRADIENT IN PLACE...RANGING FROM MID 30S
AROUND ORD NEB...TO MID 50S NEAR BELOIT KS.
WED EVENING...PRECIP SHOULD COME TO A QUICK END IN THE EAST AS THE
WAVE DEPARTS...AND LINGERED A SLIGHT POP FOR RAIN/SNOW IN
NORTHEAST ZONES THROUGH MIDNIGHT...BUT ITS VERY POSSIBLE THAT
EVERYTHING IS ALREADY OVER BY 00Z. QUIET AND DRY CONDITIONS THEN
ANTICIPATED WED NIGHT THROUGH THURSDAY NIGHT...AS A SURFACE RIDGE
AXIS MOVES ACROSS THE AREA. KEPT HIGHS THURSDAY SIMILAR TO
PREVIOUS FORECAST WITH MOST PLACES BETWEEN 34-40. LOWERED LOWS
THURS NIGHT WITH EXPECTATION OF LIGHT WINDS/CLEAR SKIES...WITH
MOST AREAS AT LEAST DOWN INTO THE UPPER TEENS.
.LONG TERM...12Z FRIDAY THROUGH MONDAY...A RELATIVELY QUIET WEATHER
PATTERN CONTINUES TO BE IN STORE FOR THE END OF THE WORK WEEK AS A
SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING
ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING WEATHER MAKER.
UNDER THIS PATTERN...NEAR ZONAL TO NORTHWESTERLY FLOW ALOFT WILL
CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS
AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN
DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE
EXTENDED WHEN THE LOW ACROSS THE DESERT SOUTHWEST EJECTS INTO THE
PLAINS. GLOBAL MODELS ARE BEGINNING TO COME INTO BETTER AGREEMENT
WITH THE HANDING OF THIS CUTOFF LOW PRESSURE SYSTEM...WITH THE LOCAL
AREA NOW EXPECTED TO BE JUST NORTHWEST OF THE TRAJECTORY OF THIS LOW
PRESSURE SYSTEM AS IT EJECTS INTO THE PLAINS EARLY NEXT
WEEK...ALBEIT GFS REMAINS SLIGHTLY FURTHER WEST WHICH COULD HAVE A
LARGE IMPACT ON LOCAL WEATHER. HOWEVER...SINCE GFS IS NOW TRENDING
CLOSER TO THE EUROPEAN...KEPT LOW POPS ACROSS THE AREA WHICH IS MORE
IN LINE WITH THE EC...AND KEPT A CHANCE OF BOTH RAIN AND SNOW AS
TEMPERATURE ALOFT INITIALLY WILL BE MORE FAVORABLE FOR RAIN...BUT
COOL DURING THE EVENT SUPPORTING A CHANCE FOR SOME SNOW.
&&
.AVIATION...12Z KGRI TAF. POOR AVIATION CONDITIONS ARE EXPECTED AT
KGRI FOR AT LEAST THE NEXT 24 HOURS WITH PREVAILING IFR OR EVEN LIFR
CIGS AND VISIBILITIES EXPECTED. LOW STRATUS...SOME FOG...AND
FREEZING DRIZZLE ARE ALL EXPECTED AT TIMES THROUGH AROUND
13/18Z...BEFORE TEMPERATURES WARM A FEW DEGREES AND -FZDZ
TRANSISTORS TO -DZ. WINDS WILL GENERALLY REMAIN LIGHT AND FROM THE
SOUTH THROUGHOUT THE PERIOD. INSTABILITY INCREASE LATE TONIGHT...BUT
THINK ANY THUNDERSTORMS THAT DO DEVELOP WILL REMAIN SOUTH OF
KGRI...AND DID NOT MENTION A CB OR -TSRA IN TAF AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ041-048-049-
062>064-074>077-083>085.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039-
040-046-047-060-061-072-073-082.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR KSZ005-006.
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR KSZ017.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
941 AM CST TUE DEC 13 2011
.DISCUSSION...
LIGHT FREEZING DRIZZLE HAVE LEFT AREA ROADWAYS WEST OF I-29 SLICK
OVERNIGHT. INCREASING THETA-E ADVECTION AND 800 MB MOISTURE
TRANSPORT LATE THIS MORNING INTO THIS AFTERNOON IS SOMEWHAT
CONCERNING...AS DENDRITIC LAYER REMAINS UNSATURATED SO PRECIPITATION
WOULD LIKELY FALL AS ADDITIONAL DRIZZLE. HAVE MADE CALLS ACROSS
WESTERN CWA IN VICINITY OF DEVELOPING RADAR ECHOS...BUT NOTHING
REACHING THE GROUND AT THIS POINT. HRRR SHOWS RELATIVELY LITTLE
ACROSS THE FORECAST AREA THROUGH 00Z WITH THE FOCUS FURTHER TO THE
SOUTH ACROSS EASTERN KANSAS...NORTHERN MISSOURI... AND SOUTHERN IOWA
ALONG THE 850 MB FRONT. KVTL REPORTED FREEZING RAIN AT THE TOP OF
THE HOUR. IF PRECIPITATION IS ABLE TO DEVELOP ACROSS WESTERN
PORTIONS OF THE FORECAST AREA...WILL ISSUE AN ADVISORY EVEN THOUGH
THE PRECIPITATION IS EXPECTED TO BE FAIRLY LIGHT IT WOULD STILL
SIGNIFICANTLY IMPACT TRAVEL SINCE IT WOULD BE ICE. SURFACE
TEMPERATURES ARE EXPECTED TO WARM THROUGHOUT THE DAY...AND SHOULD BE
MAINLY ABOVE FREEZING IN MOST LOCATIONS BY EARLY TO MID EVENING
MAKING THE LIQUID PRECIPITATION LESS OF AN ISSUE.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
IFR CEILINGS WITH MAINLY MVFR VISIBILITIES EXPECTED THROUGH THE
MORNING. CEILINGS MAY IMPROVE TO LOW MVFR THIS AFTERNOON...BUT THE
SHOULD LOWER BACK INTO IFR THIS EVENING. MIXED PRECIPITATION WILL
LIFT NORTH THIS AFTERNOON AND SPREAD ACROSS THE AREA. MAINLY RAIN IS
ANTICIPATED AT KSUX WHILE KFSD COULD SEE A BRIEF PERIOD OF -SN
BEFORE CHANGING TO ALL RAIN. BOTH LOCATIONS SHOULD GO TO IFR OR
POSSIBLY LIFR LATER TONIGHT IN -DZ...BR AND PATCHY LIGHT RAIN. KHON
MAY HAVE THE MOST PROBLEMS WITH A MIX OF FREEZING RAIN...LIGHT SNOW
AND RAIN AT TIMES.
&&
.DISCUSSION.../ISSUED AT 359 AM CST/
SOCKED IN WITH STRATUS AND LIGHT FOG THROUGH MUCH OF THE DAY AS
LIGHT WINDS GRADUALLY BECOME SOUTHEAST. NO REAL CHANCE FOR ESCAPE
FROM THE STRATUS SO HAVE SLOWED THE DIURNAL CLIMB IN THE MORNING A
BIT...BRINGING MORE OF A RISE IN THE AFTERNOON AS THE WARMER LOW
LEVEL THERMAL FIELD BUILDS NORTH. UPPER LEVEL SUPPORT AND INCREASING
MID TO UPPER LEVEL MOISTURE WILL BRING A VERY GOOD CHANCE FOR
PRECIPITATION THIS AFTERNOON AND OVERNIGHT. THE REAL QUESTION WILL
BE PRECIPITATION TYPE...WHICH WILL BE QUITE VARIABLE ACROSS THE CWA.
MOST OF NORTHWEST IOWA CAN EXPECT RAIN WITH LITTLE CHANCE OF
ANYTHING ELSE. SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA WILL
LIKELY SEE A BRIEF PERIOD OF MIXED PRECIPITATION WITH SNOW THE
LIKELY PRECIPITATION TYPE BEFORE QUICKLY CHANGING TO RAINFALL. THE
AREA MOST AT RISK WILL BE CENTRAL SOUTH DAKOTA WHERE THERMAL FIELDS
RIDE RIGHT AROUND TO 0 DEGREE ISOTHERM FROM ABOUT 800MB TO THE
SURFACE...WHICH LEAVES MUCH TO THE IMAGINATION WHEN TRYING TO
DETERMINE PRECIPITATION TYPE. FOR NOW WILL GO WITH A MIX OF FREEZING
RAIN AND SNOW...BUT CENTRAL SOUTH DAKOTA IS ALSO THE LOCATION LEAST
LIKELY TO GET ANY HEAVIER PRECIPITATION...SO ONLY EXPECTING A COUPLE
OF HUNDRETHS. HOWEVER...IF THIS FALLS AS MAINLY FREEZING RAIN THAT
WILL LIKELY BE ENOUGH TO CAUSE PROBLEMS. WILL NOT ISSUE AN ADVISORY
AT THIS TIME AS CONFIDENCE JUST NOT QUITE THERE...BUT SOMEWHERE FROM
ABOUT GREGORY TO BRULE TO CHARLES MIX COUNTY WILL BE THE HIGHEST
THREAT AREA FOR ANY ADVISORY TYPE PRECIPITATION. HIGHS MAINLY IN THE
30S TODAY.
FAIRLY STEADY TEMPERATURES TONIGHT AS A STRONG TROUGH DIGS TO THE
WEST AND SOUTHERLY FLOW ENHANCES. THIS WILL BRING A MAINLY RAIN
THREAT TO THE AREA WITH THE BEST CHANCE FOR A MIX OF PRECIPITATION
FROM CENTRAL SOUTH DAKOTA DOWN HIGHWAY 14. BUT WITH TEMPERATURES
ONLY A COUPLE OF DEGREES FROM GOING ABOVE FREEZING COULD EASILY END
UP AS MAINLY RAIN. UPPER LEVEL SUPPORT SURGES NORTHWARD AND HANGS
AROUND THROUGH THE DAY ON WEDNESDAY. SO...MORE CLOUDS...MAINLY
RAINFALL OVER THE EAST AND DECREASING CHANCES FOR PRECIPITATION
ACROSS THE WEST. AS THE WAVE PASSES WILL SEE SOME COLDER AIR FILTER
IN SO COULD BRIEFLY MIX WITH SNOW AS THE SYSTEM EXITS. NEEDLESS TO
SAY THE DIURNAL RANGE ON WEDNESDAY WILL BE MINIMAL WITH CLOUDS AND
PRECIPITATION IN PLACE. OVERALL FOR TUESDAY NIGHT INTO WEDNESDAY
ONLY EXPECTING A FEW HUNDRETHS OF LIGHT FREEZING RAIN POTENTIAL IN
SOUTH CENTRAL SOUTH DAKOTA LATE THIS AFTERNOON INTO THIS EVENING
WITH SNOW AMOUNTS GENERALLY LESS THAN AN INCH. RAINFALL AMOUNTS
COULD APPROACH A HALF AN INCH ACROSS NORTHWEST IOWA WHICH STAYS IN
THE WARM AND MOIST FLOW THE LONGEST. /08
FOR THE MOST PART...THE SIGNIFICANT FRONTAL DYNAMICS WILL WEAKEN
FAIRLY QUICKLY AND PULL EASTWARD DURING THE EVENING HOURS. BODILY
COOLING OF THE AIRMASS WOULD SUGGEST A RAIN TO SNOW TRANSITION
PULLING EAST...WITH PERHAPS SOME HELP OF DIURNAL CYCLE AND INTENSITY
IN BAND HELPING TO CHANGE OVER A BIT QUICKER. PERHAPS A QUICK HALF
INCH TO INCH OF SNOW THROUGH SOUTHWEST MINNESOTA AND HIGHEST
LOCATIONS OF NORTHWEST IOWA DURING THE EARLY EVENING.
LIKELY THAT BEYOND A NOMINAL LINGERING CHANCE IN THE FAR EAST...
LACK OF DYNAMICS BY 06Z SHOULD ELIMINATE MEASURABLE PRECIPITATION
THE REMAINDER OF THE NIGHT. AS RIDGE BUILDS IN FROM
WEST...INCREASING GRADIENT WILL MAKE FOR A BREEZY NIGHT ACROSS THE
AREA...AND MIXING KEEPING TEMPS FROM PLUMMETING TOO MUCH AS STRONGER
COLD AIR ADVECTION OCCURS LAST NIGHT
THURSDAY A WINDY AND COOLER DAY...WITH WINDS DROPPING SHARPLY TOWARD
SUNSET AS SURFACE RIDGE AXIS NOSES THROUGH THE SOUTH DAKOTA CWA AND
EXPANDS EAST THROUGH THE NIGHT. INCREASE IN CLOUDS WILL KEEP WESTERN
AND NORTHERN AREAS FROM DROPPING TOO SHARPLY IN THE WEAK FLOW...BUT
MORE EXPOSED SOUTHEAST COULD EASILY OUTDO GUIDANCE BY A FEW DEGREES
AND CLOSER TO BIAS CORRECTED VALUES SEEMS THE WAY TO HEDGE.
FRIDAY WILL FEATURE WAVE IN NORTHERN STREAM WITH MOST QG DYNAMICS
ZIPPING THROUGH NORTHERN HALF OF AREA. AIRMASS IN PLACE WILL BE
QUITE DRY IN LOW LEVELS...SO IS REALLY SLIGHT 850-700 WARM AIR
ADVECTION/FRONTOGENESIS THAT FAVORS A SMALL POP MOVING THROUGH THE
NORTHERN CWA. CARRIED SLIGHTLY BETTER CHANCE IN THE AFTERNOON IN
SOUTHWEST MINNESOTA AS EVOLUTION OF SYSTEM WILL ALLOW SATURATION
FROM ALOFT IN VICINITY OF MID LEVEL FRONTAL BOUNDARY.
CONTINUED SPLIT FLOW ALOFT IS NOT DOING PREDICTABILITY ANY FAVORS IN
THE EXTENDED RANGE. GFS/ECMWF/CANADIAN ALL PAINTING QUITE DIFFERENT
SCENARIOS FOR THE WEEKEND AND MONDAY...ESPECIALLY THE GFS SYSTEM ON
MONDAY...WHICH DOES NOT REALLY FIT IN WELL WITH THE ENSEMBLES WHICH
ARE MORE SPLIT FEATURED...AND LIKEWISE ECMWF SIMILAR SYSTEM IS
SLOWER BY A DAY OR SO AND MUCH FURTHER SOUTH. UNCERTAINTY DOES NOT
SUGGEST ENOUGH CONFIDENCE TO GROSSLY ALTER EXTENDED. HOWEVER...
PATTERN GOING INTO THE WEEKEND IS LOOSELY MATCHED TO THAT WHICH
RESULTED IN MUCH WARMER THAN PREDICTED TEMPERATURES FOR SATURDAY AND
SUNDAY. POTENTIAL OF JUST AN INCH OR LESS SNOW AND SOME LIGHT ICING
COULD STILL IMPACT TEMPERATURES A BIT...SO DID NOT GET OUT OF
CONTROL WITH WARMING...BUT DID ATTEMPT TO GET SOMEWHAT A WARMER
PICTURE... ESPECIALLY DOWNSTREAM OF BUFFALO RIDGE AND BACK IN HIGHER
TERRAIN OF SOUTH CENTRAL. IF THERE IS TO BE ANY PRECIPITATION BY
MONDAY...WHICH REMAINS QUITE A BIT IN DOUBT...THERMAL PROFILES WOULD
ALMOST CERTAINLY TAKE SNOW OUT OF THE MIX UNTIL LATE IN EVENT WITH
+2 TO +6C 850 HPA AIRMASS...MORE OF A RAIN/FREEZING RAIN SETUP
CHANGING TO SNOW AS SYSTEM UNDERGOES DYNAMIC COOLING. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
827 AM CST TUE DEC 13 2011
.UPDATE...
WEAK DISTURBANCE MOVING OVER MO AND WESTERN KY IS EXTENDING A BIT
FURTHER SE THAN THE MODELS HAVE INDICATED. WE DO HAVE REPORTS OF
DRIZZLE AND FOG ACROSS THE AREA. THE LATEST RUC SHOWS THE SLIGHT
POTENTIAL FOR MEASURABLE RAINFALL ACROSS OUR NW COUNTIES TODAY.
FURTHERMORE...CANNOT DISCOUNT THE 50 POP FOR CKV FROM THE MET.
WILL GO AHEAD AND UPDATE THE GRIDS AND INTRODUCE A LOW CHANCE OF
SHOWERS FOR OUR NW COUNTIES FOR TODAY. OTW...REMAINDER OF FCST IS
OK AS THE DRIZZLE AND FOG SHOULD CONTINUE THIS MORNING.
UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 634 AM CST TUE DEC 13 2011/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
SURFACE HIGH CENTERED OVER EASTERN OHIO THIS MORNING WITH STRONG UPPER
RIDGE BUILDING EASTWARD FROM MISSISSIPPI VALLEY.
GOOD ISENTROPIC LIFT ON 290 KELVIN SURFACE WORKING AROUND PERIPHERY
OF UPPER RIDGE EVIDENT IN LATEST MOSAIC LOOP AS LIGHT RAIN HAS
SPREAD INTO FAR WESTERN KY/TN AT DAYBREAK. BEST LIFT WILL REMAIN
WEST AND NORTH OF MY CWA TODAY. FOG...AND LOW CEILINGS WILL SHOW
IMPROVEMENT AS WE GO THROUGH THE MORNING AT BNA BECOMING VFR
DURING AFTERNOON WITH A RETURN LATE NIGHT. AT CSV FOG AND LOW
CEILINGS WILL IMPROVE BUT SLOWLY BECOMING VFR BY EARLY TO MID-
AFTERNOON BEFORE RETURNING TO IFR CONDITIONS DURING THE EVENING
AND CONTINUING OVERNIGHT.
BOYD
PREV DISCUSSION... /ISSUED 308 AM CST TUE DEC 13 2011/
DISCUSSION...
CLOUDY FOGGY NIGHT ACROSS THE MID STATE WITH A FEW AREAS REPORTING
SOME DENSE FOG AND EVEN SOME PATCHES OF DRIZZLE OCCURRING.
DESPITE THE CLOUDS AND FOG...SURFACE OBS SHOW TEMPERATURES IN THE
40S WHICH ARE AROUND 20 DEGREES WARMER THAN THIS TIME YESTERDAY.
THIS IS THE BEGINNING OF A PERIOD OF NEAR TO ABOVE NORMAL
TEMPERATURES WHICH WILL CONTINUE FOR AT LEAST THE NEXT WEEK.
FEW CHANGES HAVE BEEN MADE TO OVERALL FORECAST AS GUIDANCE
CONTINUES TO HAVE A GOOD CONSENSUS ON UPCOMING PATTERN. WATER
VAPOR IMAGERY SHOWS OUR NEXT WEATHER MAKER IN THE FORM OF AN
UPPER LEVEL LOW OFF THE SOUTHERN CALIFORNIA COAST. THIS SYSTEM IS
EXPECTED TO OPEN INTO A POSITIVELY TILTED TROUGH WHICH WILL ENTER
THE PLAINS ON WEDNESDAY AND REACH OUR REGION ON THURSDAY. AHEAD OF
THE SYSTEM...INCREASING WAA REGIME ALONG WITH WEAK RIDGING ALOFT
WILL ALLOW FOR A CONTINUED WARMING TREND TODAY INTO TOMORROW.
TEMPS WILL BE TEMPERED SOMEWHAT PER FORECAST SOUNDINGS AND TIME
HEIGHT PLOTS AS A STRONG INVERSION AROUND 850MB TRAPS LOW CLOUDS
OVER THE MID STATE TODAY...AND THICK CIRRUS MOVES OVER THE MID
STATE ON WEDNESDAY. NEVERTHELESS...HIGHS LOOK TO WARM INTO THE 50S
AREA WIDE TODAY AND WELL INTO THE 60S ON WEDNESDAY.
GFS/NAM/ECMWF IN EXCELLENT AGREEMENT ON AFOREMENTIONED TROUGH
FORCING A COLD FRONT INTO THE NORTHWESTERN CWA BETWEEN 06-12Z
WEDNESDAY NIGHT WHICH WILL MOVE ACROSS THE ENTIRE CWA ON
THURSDAY...WITH WIDESPREAD SHOWERS EXPECTED. ADDED A MENTION OF
TSTORMS AS FORECAST SOUNDINGS SHOW K INDEX VALUES RISING INTO THE
MID 30S AND SOME WEAK ELEVATED INSTABILITY...ALTHOUGH MAJORITY OF
PRECIP WILL JUST BE SHOWERS. FRONT MOVES JUST SOUTH OF CWA AS A
SECONDARY WAVE MOVES ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY...BRINGING A SECOND ROUND OF RAIN TO ALL ZONES. DESPITE
FORECAST AREA BEING IN A POST FRONTAL AIRMASS...THERMAL PROFILES
WILL BE TOO WARM TO SUPPORT ANYTHING OTHER THAN RAIN.
AFTER PRECIP ENDS FRIDAY NIGHT...A BRIEF COOLDOWN WILL OCCUR OVER
THE WEEKEND WITH TEMPS FALLING BACK TO NEAR NORMAL LEVELS. GLOBAL
MODELS THEN DEPICT A SIMILAR SYSTEM AFFECTING THE MID STATE AGAIN
MONDAY AND TUESDAY OF NEXT WEEK WITH TEMPS WARMING ABOVE NORMAL
AND A COLD FRONT BRINGING ANOTHER ROUND OF SHOWERS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
901 AM MST TUE DEC 13 2011
.DISCUSSION...
FOG PERSISTS AT MID MORNING OVER THE EAST PART OF THE CWA. THE FOG
WAS DENSE IN PLACES OVER THE SOUTHERN PANHANDLE. THE DEPTH OF THE
LOW CLOUDS AND FOG WAS BETWEEN 500 AND 1500 FEET AS OF 15Z. THE
VISIBILITIES HAVE BEEN SLOWLY IMPROVING WITH INCREASED MIXING AND
A MORE SOUTHWEST BOUNDARY LAYER WIND. THE TIMING OF THE DENSE FOG
ADVISORY OF 17Z MAY WORK OUT WELL FOR THE SOUTHERN PANHANDLE. WILL
TAKE A CLOSER LOOK SOON IN REGARDS TO THE TIMING OF THE DISSIPATION
OF THE FOG. IN A RECENT UPDATE...ADJUSTED THE AREAS OF FOG THROUGH
MIDDAY AND ADJUSTED TEMPERATURES DOWN A BIT FOR THE PANHANDLE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 452 AM MST TUE DEC 13 2011/...
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
UPDATE...WEILAND
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
452 AM MST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
448 AM MST TUE DEC 13 2011
.UPDATE FOR AVIATION DISCUSSION...
&&
.AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 435 AM MST TUE DEC 13 2011/
AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
435 AM MST TUE DEC 13 2011
.AVIATION...12Z TAF ISSUANCE...SATELLITE IMAGERY AND SURFACE
OBSERVATIONS SHOW LOW CLOUDS AND FOG OVER THE NEBRASKA PANHANDLE
AND BEGINNING TO SPREAD WESTWARD TOWARD KCYS. LIFR AND IFR CONDITIONS
SHOULD PERSIST ACROSS THE SOUTHERN NEBRASKA PANHANDLE TERMINALS
THROUGH MID TO LATE MORNING BASED ON SOUNDINGS AND HRRR OUTPUT.
INCLUDED TEMPO IFR VISBYS AND CIGS FROM 12-14Z AT KCYS. LOW LEVEL
DRYING WILL TAKE PLACE DURING THE AFTERNOON ACROSS THE SOUTHERN
PANHANDLE AND THE STRATUS WILL BEGIN TO BREAK UP AT THAT TIME.
WINDS WILL BE LIGHT DURING THE TAF PERIOD AT ALL TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
&&
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM TUESDAY FOR NEZ019-NEZ021-NEZ054-
NEZ055.
&&
$$
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 PM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE EAST OF THE AREA TONIGHT, KEEPING
THE AREA MOSTLY DRY AND TEMPERATURES SEASONABLE. A WARM FRONT
WILL LIFT INTO THE AREA ON WEDNESDAY AND BRING THE CHANCE OF
SHOWERS. SHOWERS WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD
FRONT CROSSES THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW. AT THE SURFACE, A 1031MB HIGH
IS CENTERED ACROSS WESTERN PA. DESPITE HIGH PRESSURE IN PLACE,
WEAK ISENTROPIC LIFT AT 295K ALONG WITH WARM AIR ADVECTION HAS
INSTIGATED A FEW SHOWERS ACROSS CENTRAL OHIO.
TONIGHT...AN AREA OF ISENTROPIC LIFT AHEAD OF A WARM FRONT WILL PUSH
EASTWARD INTO THE AREA OVERNIGHT. THIS WILL ALLOW FOR THE CHANCE
OF SHOWERS BY DAWN FOR AREAS EAST OF PITTSBURGH WITH A SCHC FOR
AREAS WEST. FOR TEMPERATURES OVERNIGHT, FORECAST IS CLOSEST TO THE
LAMP, A FEW DEGREES WARMER THAN A MAV/MET BLEND. LOWS WILL RANGE
FROM THE LOWER 30S IN WESTERN PA TO THE MID 30S IN EASTERN OHIO
AND NORTH-CENTRAL WV.
FOR PRECIP TYPE, 12Z OPERATIONAL MODEL RUNS INDICATE A WARMING
LOW-LEVEL THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING)
ALLOWING FOR ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH
SURFACE TEMPS A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE
LEANED AGAINST A MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR
ALOFT PREVENTING DENDRITIC GROWTH AND SATURATION LIMITED TO THE
LOWER LEVELS. WILL NEED TO MONITOR SURFACE TEMPS NEAR FREEZING
ACROSS THE EASTERN RIDGES FOR THE POTENTIAL OF FREEZING RAIN IF
PRECIP CAN ADVANCE THAT FAR EAST. WITH TDS IN THE UPPER TEENS TO
LOWER 20S, WET BULB EFFECT COULD BRING TEMPS DOWN BRIEFLY BELOW
FREEZING IF PRECIP CAN MAKE ADVANCE THAT FAR EAST. HOWEVER,
CONFIDENCE IS TOO LOW TO INCLUDE SCHC OF FZRA IN ANY GRIDS AT
THIS TIME.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A SURFACE LOW WILL LIFT NORTHEASTWARD FROM THE PLAINS INTO THE
UPPER MIDWEST. THIS SYSTEM WILL PUSH A WARM FRONT INTO THE AREA ON
WEDNESDAY. THERE IS GFS/ECMWF AGREEMENT IN ITS TIMING AND
EASTWARD EXTENT THROUGH THE UPPER OHIO VALLEY. THUS, CHANCE POPS
ARE FORECAST ACROSS THE AREA AS SHOWERS MOVE THROUGH. WARM AIR
ADVECTION WILL INCREASE AS THE FRONT PUSHES NORTH OF THE AREA
TOMORROW. THIS WILL ALLOW FOR TEMPERATURES TO WARM TO AROUND 10
DEGREES ABOVE NORMAL.
WEDNESDAY NIGHT INTO THURSDAY...THE MODELS ARE IN REASONABLE
AGREEMENT THAT A DRY SLOT WILL PUSH INTO THE AREA WITH WARM AIR
ADVECTION AS A COLD FRONT APPROACHES FROM THE WEST WED NIGHT. WITH A
BREAK IN PRECIP EXPECTED, DRY OR SCHC POPS ARE FORECAST ACROSS
MOST OF THE AREA. FORCING FROM A COLD FRONT WILL SUPPORT PRECIP
FOR THE AREA WITH CATEGORICAL POPS REACHING THE PITTSBURGH METRO
BY DAWN ON THURSDAY. MORE PERSISTENT RAINFALL IS EXPECTED THROUGH
MUCH OF THE DAY THURSDAY AS THE FRONT SLOWLY PROGRESSES ACROSS THE
OHIO VALLEY. FOR QPF WITH THIS EVENT, A HALF OF AN INCH TO AN INCH
OF RAIN IS EXPECTED ACROSS THE AREA. ONGOING WARM AIR
ADVECTION WILL ALLOW FOR TEMPS TO BE 15 TO 20 DEGREES ABOVE
NORMAL.
THURSDAY NIGHT AND FRIDAY...THE FRONT WILL CROSS THE AREA THURSDAY
NIGHT WITH A LOW-LEVEL NORTHWESTERLY FLOW AND HIGH PRESSURE
BUILDING IN FROM THE WEST IN ITS WAKE. 850MB AND LAKE ERIE TEMP
DIFFERENTIAL WILL BE SUFFICIENT TO SUPORT A FEW LAKE EFFECT SNOW
SHOWERS IN THE WAKE OF THIS SYSTEM ON FRIDAY. TEMPS ON FRIDAY WILL
BE CLOSER TO SEASONAL NORMALS AS THE ARCTIC AIR WORKS INTO THE REGION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
PER MORE HPC-PREFERRED RECENT ECMWF MODEL OUTPUT, EXPECT POST SYSTEM
CHILL DOWN TO CAUSE SCATTERED SNOW SHOWERS ACROSS NORTHWEST
PENNSYLVANIA AND POSSIBLY THE MOUNTAINS THIS WEEKEND, AND MOSTLY
CLOUDY SKIES ELSEWHERE.
A LOW PRESSURE SYSTEM, COMING NORTHEAST FROM TEXAS, MAY MAINTAIN
CLOUDS ACROSS THE AREA MONDAY AND PROVIDE MIXED PRECIPITATION
TUESDAY.
HPC GUIDANCE, GFS MOS AND NAEFS MEDIAN VALUES CONCUR THAT
TEMPERATURES SATURDAY CAN BE ABOUT 5 DEGREES COLDER THAN NORMAL.
TEMPERATURES SHOULD THEN MODERATE TO VALUES UP TO 5 DEGREES WARMER
THAN NORMAL BY MONDAY AND TUESDAY.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
THROUGH 09Z WEDNESDAY, EXPECT VFR CONDITIONS. WITH NO LOWER THAN
ALTOCUMULUS CEILINGS. AFTER 09Z WEDNESDAY, VFR SHOULD STILL BE
PREVALENT. ALTHOUGH PASSING WARM FRONT SHOULD INDUCE LOWER CEILINGS,
IN THE STRATOCUMULUS RANGE/040-060 HFT. RAIN SHOWERS WILL BE
POSSIBLE, BUT FORESEE ONLY A SMALL CHANCE OF MVFR VISIBILITIES.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
WEDNESDAY NIGHT, EXPECT PREVALENT VFR. THURSDAY INTO THURSDAY NIGHT,
EXPECT A WIDE BAND OF COLD FRONTAL SHOWERS WITH A PERIOD OF IFR
RESTRICTIONS LIKELY. FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL
MVFR STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, LINGERING MVFR
STRATOCUMULUS POSSIBLE MAINLY NORTH AND MOUNTAINS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
139 PM EST TUE DEC 13 2011
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY MOVE ACROSS THE AREA TODAY, KEEPING THE
AREA MOSTLY DRY AND TEMPERATURES SEASONABLE. A WARM FRONT WILL
LIFT INTO THE AREA ON WEDNESDAY AND BRING THE CHANCE OF SHOWERS.
SHOWERS WILL BE MORE LIKELY EARLY ON THURSDAY WHEN A COLD FRONT
CROSSES THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
18Z ENHANCED SHORT TERM FORECAST HAS BEEN TO ACCOUNT FOR INITIAL
DIMINISHING CLOUD COVERAGE ACROSS WESTERN PA AND TO ADD SCHC POPS
FOR PORTIONS OF EASTERN OHIO.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A WEST-NORTHWESTERLY 500MB FLOW. AT THE SURFACE, A 1032MB HIGH
IS CENTERED ACROSS WESTERN PA. DESPITE HIGH PRESSURE IN PLACE,
WEAK ISENTROPIC LIFT AT 295K ALONG WITH WARM AIR ADVECTION HAS
INSTIGATED A FEW SHOWERS ACROSS CENTRAL OHIO.
TODAY...THE SURFACE HIGH WILL SLOWLY SLIDE EASTWARD ACROSS WESTERN
PENNSYLVANIA. THIS WILL ALLOW FOR MOSTLY A DRY DAY. THE EXCEPTION
WILL BE THE SCHC IN EASTERN OHIO AS WEAK ISENTROPIC LIFT MOVES
INTO THIS AREA. WEAK WARM AIR ADVECTION WILL OCCUR TODAY WITH 850
TEMPS WARMING TO 0-2C ACROSS THE AREA. WITH THIS IN MIND, HIGH
TEMPS ARE A MAV/MET BLEND, RANGING FROM THE UPPER 40S ACROSS
NORTH-CENTRAL WV AND EASTERN OHIO TO THE LOWER 40S ACROSS THE
EASTERN RIDGES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WARM FRONT WILL PASS THROUGH WEDNESDAY MORNING. THERE ARE STILL
DISCREPANCIES BETWEEN OP MODELS ON THE AMOUNT OF PRECIPITATION AND
ITS EASTWARD EXTENT WITH THE FRONT. A COMPROMISE OF THE SREF, NAM
AND NMM-WRF, INDICATES THAT MOST OF THE RAIN CHANCE WILL BE OVER
OHIO AND EVENTUALLY NORTHERN PA.
RECENT OPERATIONAL MODEL RUNS INDICATE A WARMING LOW- LEVEL
THERMAL PROFILE (1000-800MB LAYER TEMPS ABOVE FREEZING) ALLOWING FOR
ANY PRECIPITATION TO BE ALL IN THE FORM OF RAIN WITH SURFACE TEMPS
A FEW DEGREES ABOVE FREEZING. IN ADDITION, HAVE LEANED AGAINST A
MIX OF RAIN AND SNOW WITH A DRIER LAYER OF AIR ALOFT PREVENTING
DENDRITIC GROWTH AND SATURATION LIMITED TO THE LOWER LEVELS. WILL
NEED TO MONITOR SURFACE TEMPS NEAR FREEZING ACROSS THE EASTERN
RIDGES FOR THE POTENTIAL OF FREEZING RAIN IF PRECIP CAN ADVANCE
THAT FAR EAST. CONFIDENCE IS TOO LOW TO INCLUDE SCHC OF FZRA IN ANY
GRIDS AT THIS TIME.
THE WARM FRONT PASSES TO THE NORTH WED AFTERNOON. THIS WILL PUT
THE AREA IN THE WARM SECTOR AND ALSO PROVIDE A BREAK IN THE RAIN
AHEAD OF THE APPROACHING COLD FRONT.
COLD FRONT WILL MOVE THROUGH LATE THURSDAY. IT LOOKS LIKE A
WIDESPREAD RAIN EVENT FOR THE AREA, BEGINNING THU MORNING AND
CONTINUING INTO THE EVENING HOURS. STRONG MID-LEVEL JET WILL PUMP
PLENTY OF MOISTURE INTO THE REGION AHEAD OF THE SFC FRONT.
A STRONG SOUTHERLY LL FLOW WILL PUSH TEMPS WILL ABOVE NORMAL ON
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BRIEF PERIOD OF LES IS POSSIBLE LATE THU/EARLY FRIDAY WITH THE
STRONG CAA BEHIND THE FRONT.
A SFC WAVE, OVER THE SE US, WILL DEVELOP ALONG THE COLD FRONT
FRIDAY. LATEST MODEL DATA IS KEEPING THIS WAVE SOUTH OF THE AREA.
HOWEVER, IT IS POSSIBLE THAT SOUTHERN LOCATIONS COULD SEE SOME
LIGHT PRECIP FRIDAY NIGHT.
HIGH PRESSURE WILL BUILD IN, KEEPING THE REMAINDER OF THE LONG
TERM DRY.
&&
.AVIATION /19Z TUESDAY THROUGH SATURDAY/...
THROUGH TONIGHT, EXPECT VFR CONDITIONS. WITH NO LOWER THAN
ALTOCUMULUS CEILINGS. DURING DAYTIME WEDNESDAY, EXPECT VFR TO
CONTINUE TO BE PREVALENT. PASSING WARM FRONT SHOULD INDUCE CEILINGS
MORE IN THE STRATOCUMULUS RANGE/040-060 HFT. RAIN SHOWERS WILL BE
POSSIBLE, BUT FORESEE ONLY A SMALL CHANCE OF MVFR VISIBILITIES.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT, EXPECT PREVALENT VFR. THURSDAY INTO THURSDAY NIGHT,
EXPECT A WIDE BAND OF COLD FRONTAL SHOWERS WITH A PERIOD OF IFR
RESTRICTIONS LIKELY. FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL
MVFR STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, VFR PREVALENT,
EXCEPT POSSIBLE LINGERING MVFR STRATOCUMULUS NORTH AND MOUNTAINS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EST TUE DEC 13 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS
AND A RIDGE OVER THE SE WITH MAINLY ZONAL FLOW FROM THE NRN PLAINS
TO NEW ENGLAND. A VIGOROUS SHORTWAVE TROUGH WAS MOVING THROUGH AZ
WHILE A WEAKER UPSTREAM SHRTWV WAS MOVING INTO SRN SD. AT THE
SFC...A RIDGE EXTENDED FROM NORTHERN QUEBEC TO LAKE SUPERIOR
RESULTING IN WEAK ACYC FLOW OVER THE CWA WITH NO PCPN INDICATED BY
RADAR. WITH THE MILD/MOIST AIRMASS IN PLACE...PATCHY FOG LINGERED
OVER LOCATIONS NEAR THE WI BORDER.
&&
.SHORT TERM...TONIGHT AND WEDNESDAY
TONIGHT...AS THE HIGH SLIDES OFF TO THE SE...SRLY LOW LEVEL FLOW
WILL INCREASE WEAK UPSLOPE FLOW INTO PORTIONS OF WEST AND CENTRAL
UPPER MI MAY BE ENOUGH TO SUPPORT SOME PATCHY -DZ/-FZDZ AFT 06Z EVEN
THOUGH OVERALL LOW LEVEL (925-850 MB) LIFT IS VERY WEAK...PER
NAM/RUC...280K ISENTROPIC PROGS. OTHERWISE...WITH LITTLE DIURNAL
TEMP CHANGE IS EXPECTED OVER THE AREA. AREAS OF FOG...SOME LCLY
DENSE...MAY ALSO THICKEN WITH SLIGHT INCREASE IN MOISTURE ADVECTION.
WEDNESDAY...AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND MOVES
TOWARD THE UPPER MS VALLEY...LOW/MID LEVEL WAA AND MOISTURE
ADVECTION WILL INCREASE. THIS SHOULD BRING AN AREA OF LIGHT PCPN
OVER THE ENTIRE CWA BY AFTERNOON...PER NAM/GFS 290K-295K ISENTROPIC
PROGS. NAM WET-BULB ZERO HEIGHTS SUGGEST THAT THE PCPN SHOULD BE
MAINLY RAIN. HOWEVER...GIVEN LOW LEVEL TEMP PROFILES NEAR 0C OVER
THE INTERIOR WEST...CANNOT RULE OUT SOME SNOW. ANY ACCUMULATIONS
WOULD BE MINIMAL. EVEN THOUGH TEMPS WILL BE ABOVE FREEZING WHEN THE
RAIN ARRIVES...SOME UNTREATED ROADS MAY STILL BE COLD ENOUGH TO
CREATE PATCHY ICY SPOTS.
.LONG TERM /WED NIGHT THROUGH NEXT TUESDAY/...
SHORTWAVE CURRENTLY ROUNDING THE UPPER TROUGH OFF THE COAST OF SRN
CA WILL MOVE TOWARDS THE AREA LATE WED AFTN AND MOVE ACROSS THE AREA
WED EVENING. MODELS FAIRLY CONSISTENT ON THE MAIN ENERGY FROM THE
SHORTWAVE MOVING ACROSS CNTRL/ERN UPPER MI...WHICH WILL GRADUALLY
INTENSIFY THE LOW MOVING FROM IOWA AT 00Z THURS TO SE ONTARIO AT 12Z
THURS. OTHER THAN THE FAST AND NW OUTLIER 12Z NAM...MAIN DIFFERENCES
BETWEEN THE MODELS IS IN THE INTENSITY OF THE LOW. 06-12Z GFS RUNS
ON THE STRONG SIDE AND 00Z ECMWF ON WEAKER SIDE. WILL FOLLOW A BLEND
OF THE TWO SINCE TRACKS ARE SIMILAR AND ONLY MINOR DIFF IN THE
THERMAL PROFILES.
DURING THE EVENING...06 AND 12Z GFS SHOWING STRONG FGEN FROM
H800-400 ACROSS THE CWA. THINK THE BEST FORCING WILL BE ALONG THE
H800-600 FGEN AREA...WHERE THERE IS ABUNDANT MOISTURE AND STRONG
AGEOSTROPHIC UPWARD CIRCULATION. FARTHER NW...APPEARS TO BE A DECENT
H700-500 DRY AIR LAYER...AND DOWNWARD CIRCULATION MAY LIMIT PCPN
FARTHER NW TOWARDS A KIWD TO KCMX LINE. OVER THE E...EXPECT A STRONG
AREA OF H850-700 WAA AND 285-300K SFC ISENTROPIC ASCENT DURING THE
EVENING. THINK THE EXISTING 100 POPS LOOK GOOD AND WILL LEAVE THEM
AS IS. THEN HAVE A GRADUAL LOWERING HEADING OVER THE WEST TOWARDS
HIGH END LIKELY. COULD BE A SHARP CUTOFF TO THE WEST EXTENT OF THE
PCPN OVER THE WRN HALF OF LK SUPERIOR WITH THE FGEN CIRCULATION...SO
TRIED TO SHOW THAT POTENTIAL.
P-TYPE FOR THE WED NIGHT PERIOD IS WHERE THINGS GET TRICKY. BUFKIT
SOUNDINGS FROM THE GFS SHOW AN ISOTHERMAL PROFILE FROM SFC TO
5-6KFT. WITH THAT TYPE OF SITUATION...IT WILL LIKELY BE SNOW WHERE
LAYER IS NEAR 0C AND THEN RA/SN AROUND 1C AND ALL RA AROUND 2-3C.
KCMX MAY BE FAR ENOUGH N AND AWAY FROM THE WARM SURGE TO KEEP PCPN A
RA/SN MIX OR POSSIBLY EVEN ALL SNOW. THEN HEADING S AND E ACROSS THE
CWA...EXPECT A TRANSITION TO ALL RAIN. BIGGEST CONCERN IS GETTING
THAT RA/SN AREA PINNED DOWN AND STILL DON/T HAVE A GREAT FEEL...BUT
IT SHOULD BE OVER THE NW THIRD. FORTUNATELY...THE HEAVIEST QPF WILL
LIKELY BE TO THE SE OF THE UNCERTAIN AREA FOR RA/SN...SO IT SHOULD
LIMIT THE IMPACT IF IT DOES END UP ALL SNOW.
LAST COUPLE OF RUNS OF THE GFS HAVE REALLY BUMPED UP THE QPF IN THE
FGEN LOCATION MOVING ACROSS CNTRL UPPER MI...WITH LIQUID AMOUNTS
EXCEEDING 0.75IN...BUT IT IS LIKELY DUE TO THE MORE WRAPPED UP LOW
SOLN. WILL NOT GO THAT HIGH...BUT WILL NEED TO BE MONITORED IF
STRONGER LOW SOLN PANS OUT. OTHERWISE...EXPECT 0.25 TO 0.4 OF LIQUID
ACROSS THE SE HALF OF THE CWA...MAINLY DURING THE EVENING.
MAIN ENERGY AND DEEPER H700-500 MOISTURE PULLS OUT OVERNIGHT WED AND
HAVE DIMINISHING POPS TO ACCOUNT FOR THAT. P-TYPE IS AGAIN A CONCERN
HEADING INTO THE OVERNIGHT...SINCE THE DEEPER MOISTURE PULLS OUT
BEFORE THE COLDER AIR ARRIVES LATE WED NIGHT INTO THURS. THIS WILL
CUT THE POTENTIAL FOR ICE CRYSTALS IN THE CLOUD WAY DOWN AND LIMIT
THE POTENTIAL FOR SNOW. WITH TEMPERATURES DROPPING TOWARDS FREEZING
OVER THE WEST TOWARDS 12Z THURS...DID KEEP A MENTION OF -FZRA IN THE
FORECAST LATE...BUT POTENTIAL SEEMS LIMITED DURING THE OVERNIGHT
HOURS WITH THE SHORT PERIOD OF AT OR BELOW FREEZING TIME.
OTHERWISE...WILL ONLY MENTION A LOW CHANCE FOR SNOW OVER THE WEST
OVERNIGHT DUE TO LIMITED ICE CRYSTAL PRESENCE AND RAIN OVER THE
CENTRAL AND EAST. THINK THE BIGGEST HAZARD IS MORE LIKELY TO BE THE
WET ROADS ICING UP ON THURS...AS TEMPS FALL BELOW FREEZING THROUGH
THE DAY.
NRN STREAM UPPER TROUGH WILL SWEEP THROUGH THE CWA ON THURS. STILL
DIFFERENCES IN THE SPEED/INTENSITY IN THE MODELS WITH THIS
WAVE...BUT ALL HAVE THE GENERAL IDEA OF IT MOVING THROUGH THE UPPER
GREAT LKS ON THURS. THIS WAVE WILL DROP H850 TEMPS THROUGH THE DAY
TO -12C OVER THE W BY 00Z FRI. THESE COLDER TEMPS WILL STAY OVER THE
AREA THROUGH THE DAY FRI...ANOTHER WEAKER SHORTWAVE DROPS ACROSS THE
AREA. WITH TEMPS ALOFT PUTTING THE CLOUD LAYER BACK INTO THE ICE
CRYSTAL AREA ON THURS...EXPECT TO CHANCES FOR SNOW AS THE P-TYPE TO
BE ON THE INCREASE FROM WEST TO EAST. SHORTWAVE ENERGY WILL HELP
ENHANCE THE DEVELOPING LES THROUGH THE DAY. WILL CONTINUE TREND OF
HIGHER POPS OVER THE WEST IN THE MORNING WITH LES DEVELOPING AND
SHORTWAVE ARRIVING...THEN INCREASE LES POPS OVER THE E UNDER NW
WINDS IN THE AFTN INTO THURS NIGHT. IN ADDITION...WITH THE LOW
INTENSIFYING TO THE NE OF THE AREA...EXPECT A BREEZY DAY ON THURS
ACROSS THE AREA. THE HIGHEST WINDS SHOULD BE OVER THE E NEAR LK
SUPERIOR...WHERE WINDS COULD GUST TO 40-45MPH LATE IN THE AFTERNOON.
SFC RIDGE QUICKLY MOVES FROM W TO E OVER THE CWA ON THURS NIGHT INTO
FRI. MODELS SHOWING VERY PRONOUNCED H925-700 DRYING WITH THE ARRIVAL
OF THE RIDGE...SO HAVE TRENDED BACK LES POPS...ESPECIALLY OVER THE
WEST WHERE BUFKIT SOUNDINGS SHOWING INVERSION HEIGHTS FALLING
TOWARDS 3KFT. DID KEEP LIKELY/S OVER THE NW WIND FAVORED E LOCATIONS
THURS NIGHT INTO FRI MORNING...BUT DROPPED TO CHANCES IN THE AFTN AS
THE DRY AIR LIMITS POTENTIAL.
DAYS 4 THROUGH 7 /FRI NIGHT THROUGH NEXT TUESDAY/...
WEAK SHORTWAVE MOVING ACROSS THE AREA FRI NIGHT WILL BRING A LITTLE
MORE MOISTURE TO THE AREA AND KEEP COLDER AIR IN PLACE. EXPECT
ONGOING LES TO CONTINUE OVER THE E...WITH WINDS GRADUALLY SHIFTING
MORE WRLY. LES MAY TRY TO REDEVELOP OVER THE W WITH THE ARRIVAL OF
THE SHORTWAVE AND ADDITIONAL LLVL MOISTURE. WILL GO WITH LOW CHANCES
OVER THE KEWEENAW WITH THE MORE WRLY WINDS AND THEN LOW END LIKELY/S
OVER THE EAST.
UPPER TROUGH SHIFTS E ON SAT AND DRAGS A SFC TROUGH OVER NRN LK
SUPERIOR AND SRN ONTARIO THROUGH THE DAY AND INTO SAT NIGHT. THERE
HAS BEEN A STRONGER TREND WITH THE SFC FEATURES AND UPPER FORCING
OVER THE LAST DAY FOR THE SAT AND SAT NIGHT PERIOD...SO HAVE BUMPED
POPS UP TO SLIGHTS OVER THE NRN U.P. AND CHANCES OVER THE LAKE.
SOME DIFFERENCES APPEAR IN THE EXTENDED MODELS ON SUN INTO MON WITH
THE HANDLING OF A POTENTIAL RIDGE IN THE NRN STREAM AND A CLOSED LOW
OVER THE SW CONUS. LATEST 12Z RUN OF THE GFS HAS TRENDED SLOWER WITH
THE EXIT OF THE UPPER LOW OVER THE SW CONUS SUN INTO MON...AND MORE
IN LINE WITH THE 00Z ECMWF...SO HAVE FOLLOWED THAT FOR THE REST OF
THE EXTENDED. SFC RIDGE WILL MOVE ACROSS THE CWA ON SUN INTO SUN
NIGHT. NRN STREAM SHORTWAVE WILL APPROACH THE AREA MON INTO
TUES...BRINGING ANOTHER LOW CHANCE OF PCPN. HAS BEEN A GOOD AMOUNT
OF FLUCTUATION IN H850 TEMPS AFTER SUN...SO HAVE LIMITED CONFIDENCE
IN VALUES...BUT APPEARS THAT TEMPS WILL SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
LOW-LEVELS SHOULD REMAIN MOIST THROUGH THE TAF PERIOD WITH LIMITED
MIXING AS A WEAK TROUGH OF LOW PRESSURE REMAINS OVER UPPER MICHIGAN.
ALL TAF SITES WILL EXPERIENCE LOWER IFR CONDITIONS WITH CONDITIONS
POSSIBLY FALLING TO AROUND AIRPORT MINIMUMS WHEN WINDS PROVIDE
ADDITIONAL UPSLOPE LIFT. SOME DRYING MAY WORK INTO THE AREA TONIGHT
AS WINDS BECOME MORE SOUTHERLY. BEST CHANCE OF IMPROVEMENT WILL BE AT
KIWD WITH DOWNSLOPE WINDS...WHILE KSAW WILL REMAIN IFR AS SRLY WINDS
ADD ADDITIONAL MOISTURE OFF OF LK MICHIGAN AND ALSO PROVIDE SOME
UPSLOPE. CONFIDENCE IN DETAILS THROUGH ENTIRE TAF PERIOD IS ON THE
LOW SIDE. IN GENERAL...SIGNIFICANT IMPROVEMENT IS NOT ANTICIPATED
THROUGH WEDNESDAY MORNING.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LIGHT SOUTHERLY WINDS WILL INCREASE INTO THE 15 TO 25 KT RANGE OVER
THE CENTRAL AND EAST PORTIONS OF THE LAKE WED AHEAD OF LOW PRESSURE
DEVELOPING IN THE PLAINS. THE LOW IS FCST TO DEEPEN AS IT LIFTS
ACROSS THE UPPER LAKES BY THURSDAY MORNING. STRONGEST WINDS THIS
WEEK WILL OCCUR JUST IN THE WAKE OF THE LOW THURSDAY MORNING THROUGH
MIDNIGHT THURSDAY NIGHT. CONFIDENCE THAT 35-40 KT GALES WILL OCCUR
IS HIGH SO THE WATCH CONTINUES FOR MUCH OF LK SUPERIOR. STRONG WINDS
WILL DIMINISH ON FRI WITH THE SLOW APPROACH OF A HIGH PRESSURE
RIDGE. A STRONGER SW FLOW WILL REDEVELOP ON SAT AFTER THIS HIGH
SHIFTS TO THE SE WITH WINDS TO AROUND 30 KT OVER WEST AND CENTRAL
PORTIONS OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
LSZ264>267.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
410 PM CST TUE DEC 13 2011
.DISCUSSION...
MAIN EMPHASIS THIS FORECAST WAS SPENT ON SYSTEM THAT WILL IMPACT
THE AREA TONIGHT THROUGH WEDNESDAY...WITH BASICALLY AN ALL RAIN
SCENARIO EXPECTED. AFTER THAT...LOOKS MAINLY DRY...WITH THE
PROSPECTS OF A BROWN CHRISTMAS FOR MOST OF THE NRN PLAINS/UPPER MS
VALLEY LOOKING LIKE A DISTINCT POSSIBILITY. THIS WOULD BE THE
FIRST SNOW FREE CHRISTMAS IN THE TWIN CITIES /AND MOST OF THE REST
OF THE AREA FOR THAT MATTER/ SINCE 2006.
THIS AFTERNOON...DEEP UPPER LOW OVER THE DESERT SW...WHICH BROUGHT
SOME DECENT RAINS/SNOWS TO AZ BEGINNING TO LIFT ENE. MOISTURE
PLUME ON WATER VAPOR HAS BEEN SPREADING NE...WITH SCT RADAR RETURNS
WORKING NORTH ACROSS NEB/IA. 12Z MODELS ARE FAIRLY CONSISTENT
WITH A SCENARIO FOR THIS SYSTEM SETTING UP WHERE WE GET A WAA WING
OF PRECIP TONIGHT /WHAT IS NOW GATHERING STEAM DOWN BY
OMAHA/...FOLLOWED BY A BIT OF A LULL IN PRECIP WED MORNING BETWEEN
THE WAA PRECIP TONIGHT...AND WHAT LOOKS TO BE A BAND OF
DEFORMATION PRECIP THAT SETS UP WED AFTERNOON. SOME DISAGREEMENT
ON WHERE THIS SECOND BAND OF PRECIP SETS UP...BUT THE
GEM/GFS/ECMWF ALL SHOW A SW-NE ORIENTED BAND OF RAIN SETTING UP
SOMEWHERE BETWEEN THE TWIN CITIES AND ROCHESTER DURING THE
AFTERNOON. ONE BIG WORRY I HAVE FOR THIS SYSTEM IS THE FACT THAT
LOW LEVEL MOISTURE TRANSPORT IS PEGGED TO RIDE UP INTO SE IA AND
SE WI...REMAINING WELL SE OF HERE. IN ADDITION...STILL INDICATIONS
FROM THE BEST LI`S OFF THE NAM/GFS THAT THIS REGION OF MOISTURE
TRANSPORT COULD ALSO SEE THUNDER ON WEDNESDAY...THIS COULD CONSUME
A LOT OF THE MOISTURE THAT WOULD OTHERWISE COME UP HERE...WITH THE
RELATIVELY DRY 12Z NAM SCENARIO FOR THE MPX CWA NOT OUT OF THE
QUESTION. AS FOR THAT AFTERNOON DEFORMATION BAND...FGEN WITHIN IT
LOOKS TO BE FAIRLY STRONG...AND IF IT DOES SETUP...LIKE THE IDEA
THE GFS GIVES OF A BAND OF A HALF INCH OR MORE OF RAIN SETTING UP
WITH IT. UNDER NORMAL DECEMBER CIRCUMSTANCES...THIS WOULD RESULT
IN A HEALTHY BAND OF INTENSE SNOWFALL...BUT ALL INDICATIONS SHOW
THIS BEING A VERY WARM SCENARIO...WITH ANY WINTRY PRECIP NOW
BEGINNING TO LOOK UNLIKELY...AS PRECIP LOOKS TO MOVE EAST OF THE
AREA BEFORE THICKNESSES BEGIN TO CRASH.
AS FOR THE POSSIBILITY OF WINTER WEATHER STATEMENTS
TONIGHT FOR WRN MN...DECIDED AGAINST DOING SO FOR TWO REASONS.
FIRST...THERE ARE NO SITES LEFT IN THE MPX CWA WITH TEMPERATURES
AT OR BELOW 32F. WITH SE FLOW EXPECTED TO REMAIN IN PLACE ALL
NIGHT...IT IS HIGHLY QUESTIONABLE IF ANYONE WILL FALL BELOW
FREEZING TONIGHT...KEEPING ALL PRECIP IN THE FORM OF LIQUID RAIN
TONIGHT. SECOND...WITH THE 12Z MODEL RUNS...IT IS QUESTIONABLE IF
AREAS NW OF A RWF TO MILLE LACS LAKE LINE WILL SEE MUCH IN THE WAY
OF PRECIP OUT OF THIS EVENT...FURTHER DECREASING THE CONFIDENCE IN
THE NEED FOR ANY WINTER STATEMENTS TONIGHT.
THIS SYSTEM WILL PULL OUT OF THE AREA THURSDAY NIGHT...WITH
THURSDAY BEING CHARACTERIZED BY STRONG CAA MOST OF THE DAY...WITH
A COUPLE OF BELOW TO NEAR NORMAL TEMPERATURE DAYS TO END THE WEEK.
FOR WEDNESDAY NIGHT...WARMED THE LOWS SEVERAL DEGREES ACROSS ERN
MN AND WRN WI...AS MODELS SHOW STRONG CAA WAITING UNTIL THE DAY ON
THURSDAY TO MOVE THROUGH...WITH CLOUDS HANGING AROUND MOST OF THE
NIGHT. GIVEN THE STRONG CAA ON THURSDAY...LOOKS TO BE YET ANOTHER
DAY WHERE TEMPERATURES GO SIDEWAYS OR SLOWLY FALL DURING THE DAY.
USED A NON-DIURNAL TREND IN TEMPERATURES WEDNESDAY NIGHT AND
THURSDAY BASED OFF THE REGIONAL GEM.
GOING INTO THE WEEKEND...WRLY FLOW WILL QUICKLY SET IN...WITH
HIGHS BACK INTO THE 30S ALREADY RETURNING FOR SATURDAY. SUNDAY
LOOKS TO WARM EVEN FURTHER AS SRLY FLOW SETS UP OUT AHEAD OF THE
NEXT FRONTAL BOUNDARY...WHICH THE ECMWF CONTINUES TO SHOW MOVING
IN ON MONDAY. DEPENDING ON HOW MUCH SUN THERE THERE IS...SUNDAY
COULD BE YET ANOTHER CANDIDATE THIS MONTH FOR HIGHS IN THE 40S.
FOR THE MONDAY SYSTEM...THE GFS/ECMWF SHOWING A SPLIT FLOW SCENARIO
SETTING UP...WHERE ONCE AGAIN THE MPX AREA ENDS UP BETWEEN WEATHER
SYSTEMS AND DRY. FOR THIS SYSTEM...MODELS SHOW ANOTHER UPPER LOW
CLOSING OFF OVER THE DESERT SW OVER THE WEEKEND...WITH NRN STREAM
ENERGY MOVING ACROSS THE NRN PORTIONS OF THE SRN CANADIAN
PROVINCES. THIS NRN WAVE LOOKS TO BE TOO FAR NORTH TO IMPART MUCH
INFLUENCE ON THE SW LOW. AS A RESULT...THE GFS/ECMWF TAKE THIS LOW
WELL SOUTH OF THE AREA...KEEPING THE MPX AREA HIGH AND DRY. AS THE
SAYING GOES...WHEN IN DROUGHT LEAVE IT OUT.
&&
.AVIATION... /18Z TAF ISSUANCE/
VFR CEILINGS CONTINUE TO WORK SLOWLY NORTHWEST ACROSS THE TWIN
CITIES. IMPROVEMENT SHOULD WORK INTO KRNH BY 21Z. ONE CONCERN IS
THE NEGATIVE CU RULE WHICH WOULD SUGGEST THAT A BKN LAYER IN THE
015-020 RANGE COULD REDEVELOP THIS AFTERNOON. RUC PROFILE DATA
SHOWS THIS IMPROVING SITUATION NICELY AND ACTUALLY HAS 040
CEILINGS PREVAILING TO NEAR 08Z. THERE IS SOME CONCERN THAT THIS
LOW LEVEL DRYING MAY MAKE IT INTO KSTC THIS EVENING. THE OTHER
PROBLEM IS VISIBILITIES. IMPROVEMENT WILL OCCUR AT KAXN AND KSTC
AS THE SE LOW LEVEL FLOW INCREASES. THESE TWO SITES SHOULD SEE
3SM IN THE 21Z-22Z TIME FRAME. RAIN WILL SPREAD ACROSS THE CWA
TONIGHT AS A WAVE OF LOW PRESSURE APPROACHES FROM THE SW. THE
TIMING ON THE RAIN REMAINS SIMILAR TO THE PREVIOUS TAF PACKAGE.
THERE IS STILL SOME POTENTIAL FOR -FZRA AT KAXN AT THE BEGINNING
OF THE PRECIPITATION WITH RAIN ELSEWHERE. THE PRECIPITATION COMES
IN TWO PHASES WITH KAXN...KSTC AND KRWF DRYING OUT WEDNESDAY
MORNING WHILE ANOTHER ROUND OF RAIN SPREADS NORTHEAST ACROSS
KMSP...KRNH AND KEAU.
KMSP...CEILINGS AROUND 040 EXPECTED THIS AFTERNOON WITH TEMPORARY
BKN015. WENT PREDOMINANT BKN-OVC015 AT 23Z BUT THIS MAY BE TOO
EARLY BASED ON THE RAPID UPDATE CYCLE AND PERHAPS VFR CEILINGS
LAST THROUGH THE EVENING. RAIN EXPECTED INTO THE AIRFIELD AFTER
06Z AND LASTING TO NEAR DAYBREAK. A BREAK IN THE RAIN WEDNESDAY
MORNING WITH MORE LIGHT RAIN OCCURRING WEDNESDAY AFTERNOON AS LOW
PRESSURE ACROSS NORTHERN IA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/RAH
AREA FORECAST DISCUSSION
NWS DULUTH MN
207 PM CST TUE DEC 13 2011
.UPDATE...
EXPIRED THE WIS COUNTIES FROM THE FZRA ADVISORY AS TEMPS HAVE
WARMED ENOUGH TO MELT THE ICE COVERED ROADS FROM THIS MORNING. THE
WIS DEPT OF TRANSPORTATION REPORTS ROAD CONDITIONS HAVE IMPROVED
TO GOOD WINTER DRIVING ACROSS NRN WIS. ALTHOUGH A FEW LOCATIONS
IN THE HIGHER TERRAIN MAY FALL AROUND FREEZING
OVERNIGHT...EXPECTING THE SOUTH WINDS TO KEEP MAJORITY OF THE AREA
WARM ENOUGH TO PREVENT ICE ACCUMULATIONS WITH LINGERING DRIZZLE OR
FOG.
&&
.PREV DISCUSSION... /ISSUED 557 AM CST TUE DEC 13 2011/
AVIATION...12Z TAF ISSUANCE...
LIFR/IFR CIGS AND VSBYS ACROSS THE REGION THIS MORNING WILL
IMPROVE SLIGHTLY BY THE LATE MORNING...WITH -FZDZ AROUND DLH AND
HIB TERMINALS. CIGS COULD POSSIBLY LIFT TO LOW-END MVFR...BUT WILL
LOWER AGAIN BY 00Z TO IFR AND POSSIBLY LIFR LATER IN THE EVENING
AND THROUGH THE OVERNIGHT. WILL SEE A CHANCE OF -FZDZ AGAIN THIS
EVENING AS COLD AIR REMAINS IN PLACE BUT A SURGE OF LOW LEVEL
MOISTURE GETS PUMPED INTO THE REGION FROM THE SOUTH. ENOUGH WARM
AIR AROUND BRD WILL KEEP PRECIP RAIN AND/OR SNOW. PATCHY IFR FOG
WILL ALSO RETURN AGAIN TONIGHT.
PREV DISCUSSION... /ISSUED 403 AM CST TUE DEC 13 2011/
SHORT TERM...THE MAIN SHORT TERM FOCUS IS ON FREEZING DRIZZLE AND
DENSE FOG POTENTIAL.
AT 4 AM...WIDESPREAD LOW CLOUDS AND FOG BLANKETED THE NORTHLAND.
DENSE FOG CONTINUED ACROSS THE SOUTHERN TIER OF COUNTIES...
ESPECIALLY ON THE WISCONSIN SIDE. FREEZING DRIZZLE CONTINUED FOR
AREAS BORDERING LAKE SUPERIOR...WITH FREEZING DRIZZLE CONTINUING
AT THE DULUTH AIRPORT. UNTREATED SURFACES WERE VERY SLICK AS OF 4
AM...ESPECIALLY SIDEWALKS AND UNTREATED SECONDARY ROADS.
SHORT RANGE MODELS ARE IN GOOD AGREEMENT REGARDING THE
CONTINUATION OF DRIZZLE AND FREEZING DRIZZLE ACROSS THE COASTAL
AREAS TODAY AND TONIGHT. THE LOCAL WRF SOLUTION...THE HRRR AND
EVEN THE NAM12 CONTINUE TO INDICATE SMALL POPS ACROSS THE AREA
TODAY...AND CONTINUING INTO TONIGHT AS EASTERLY WINDS BRING THE
SATURATED AIR THROUGHOUT THE REGION. HAVE EXTENDED THE ADVISORY
THROUGH TONIGHT. WILL CONTINUE THE DENSE FOG ADVISORY FOR AREAS TO
THE SOUTH THROUGH MID MORNING AND MAY NEED TO EXTEND IT IF
CONDITIONS SHOW NO SIGN OF IMPROVING AT THAT TIME.
THE NEXT FOCUS IS THE UPPER LEVEL AREA OF LOW PRESSURE THAT IS
EXPECTED TO LIFT INTO THE GREAT LAKES REGION. COULD SEE SOME LIGHT
ACCUMULATIONS IN SPOTS ON WEDNESDAY...BUT LOOKS LIKE THERE IS A
BETTER CHANCE OF SNOW ACROSS MAINLY NW WI.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY. EARLY PART OF THE
EXTENDED PERIOD IS CHARACTERIZED BY THE JOINING OF TWO UPPER SHORT
WAVES INTO ONE ACROSS THE N-CENTRAL SECTIONS OF THE COUNTRY. THE
PRIMARY S/W TO THE SOUTH WILL EJECT NEWD FROM THE MAIN LONG-WAVE
TROUGH STILL SITUATED BACK TO THE WEST ACROSS THE SRN PLAINS. A
SECONDARY S/W WILL SLIDE IN FROM THE W/NW...ALMOST AS A CLIPPER
TYPE SYSTEM. THE TWO SHRT WVS WILL MORPH INTO ONE AS THEY ENTER
THE GREAT LAKES REGION...AND EVENTUALLY LIFT INTO ERN CANADA. AS
THIS SYSTEM ENTERS THE UPPER MIDWEST ON WED...AN AREA OF WARM AIR
WILL ADVECT IN AHEAD OF THE SYSTEM INTO WI AND ALLOW PRECIP TO
FALL IN THE FORM OF EITHER A RAIN/SNOW MIX OR ALL RAIN WED EVENING
OVER NW WI. COULD SEE AN INCH OF SNOW ACROSS PARTS OF NE MN AS
THIS SYSTEM PASSES THROUGH. WILL SEE RAIN CHANGE TO SNOW AFTER
MIDNIGHT WED AND THUR MORNING IN WI AS COLD AIR FILTERS IN ON THE
BACK SIDE OF THIS FAST MOVING SYSTEM. THE NW WINDS...AND COLD AIR
ALOFT WILL KEEP SOME LIGHT SNOW SHOWERS ACROSS THE ARROWHEAD
THROUGH THE DAY THUR...AND ALSO PRODUCE SOME LAKE EFFECT SNOW
ALONG THE SOUTH SHORE IN THE SNOW BELT REGION OF NW WI THROUGH
LATE THUR MORNING. RAPID DRY AIR ADVECTING IN WILL LIMIT THE
DURATION OF THE LES. HIGH PRESSURE BUILDS IN LATE THUR/FRIDAY
ALONG WITH COLDER TEMPERATURES. DRY CONDITIONS ARE EXPECTED
THROUGH SUNDAY AS THE PATTERN BECOMES QUIET AND TEMPS BECOME
RELATIVELY WARM FOR MID DECEMBER. SLIGHT CHANCES FOR SNOW DEVELOP
AGAIN BY EARLY NEXT WEEK.
AVIATION.../06Z TAF DISCUSSION/
LIFR/IFR CIGS/VSBYS WILL PREVAIL THROUGH 15Z WITH A GRADUAL
INCREASE TO MVFR CIGS. AREAS OF -DZ AND BR/FG ARE ALSO EXPECTED.
SOME PATCHY -FZDZ IS POSSIBLE AT KDLH. THE -DZ AND BR/FG SHOULD
END AROUND 19Z EXCEPT AT KDLH WHERE IT MAY PERSIST THROUGH THE
FORECAST CYCLE. -FZDZ MAY RETURN TO THE KDLH VCNTY FROM 23Z TO
02Z. -FZRA IS POSSIBLE AT KBRD AFTER 14/00Z AHEAD OF THE SYSTEM
LIFTING NEWD OUT OF THE PLAINS.
&&
.POINT TEMPS/POPS...
DLH 32 35 27 27 / 30 70 60 20
INL 26 34 19 20 / 20 40 40 20
BRD 31 35 22 26 / 50 60 40 10
HYR 33 36 30 30 / 30 80 80 20
ASX 32 37 30 31 / 30 80 80 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FREEZING RAIN ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ012-
019>021-037.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GRANING
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1159 AM CST TUE DEC 13 2011
.AVIATION... /18Z TAF ISSUANCE/
VFR CEILINGS CONTINUE TO WORK SLOWLY NORTHWEST ACROSS THE TWIN
CITIES. IMPROVEMENT SHOULD WORK INTO KRNH BY 21Z. ONE CONCERN IS
THE NEGATIVE CU RULE WHICH WOULD SUGGEST THAT A BKN LAYER IN THE
015-020 RANGE COULD REDEVELOP THIS AFTERNOON. RUC PROFILE DATA
SHOWS THIS IMPROVING SITUATION NICELY AND ACTUALLY HAS 040
CEILINGS PREVAILING TO NEAR 08Z. THERE IS SOME CONCERN THAT THIS
LOW LEVEL DRYING MAY MAKE IT INTO KSTC THIS EVENING. THE OTHER
PROBLEM IS VISIBILITIES. IMPROVEMENT WILL OCCUR AT KAXN AND KSTC
AS THE SE LOW LEVEL FLOW INCREASES. THESE TWO SITES SHOULD SEE
3SM IN THE 21Z-22Z TIME FRAME. RAIN WILL SPREAD ACROSS THE CWA
TONIGHT AS A WAVE OF LOW PRESSURE APPROACHES FROM THE SW. THE
TIMING ON THE RAIN REMAINS SIMILAR TO THE PREVIOUS TAF PACKAGE.
THERE IS STILL SOME POTENTIAL FOR -FZRA AT KAXN AT THE BEGINNING
OF THE PRECIPITATION WITH RAIN ELSEWHERE. THE PRECIPITATION COMES
IN TWO PHASES WITH KAXN...KSTC AND KRWF DRYING OUT WEDNESDAY
MORNING WHILE ANOTHER ROUND OF RAIN SPREADS NORTHEAST ACROSS
KMSP...KRNH AND KEAU.
KMSP...CEILINGS AROUND 040 EXPECTED THIS AFTERNOON WITH TEMPORARY
BKN015. WENT PREDOMINANT BKN-OVC015 AT 23Z BUT THIS MAY BE TOO
EARLY BASED ON THE RAPID UPDATE CYCLE AND PERHAPS VFR CEILINGS
LAST THROUGH THE EVENING. RAIN EXPECTED INTO THE AIRFIELD AFTER
06Z AND LASTING TO NEAR DAYBREAK. A BREAK IN THE RAIN WEDNESDAY
MORNING WITH MORE LIGHT RAIN OCCURRING WEDNESDAY AFTERNOON AS LOW
PRESSURE ACROSS NORTHERN IA.
&&
.DISCUSSION... /ISSUED 433 AM CST TUE DEC 13 2011/
SUMMARY...PRECIP STILL ON PACE TO MOVE IN TONIGHT AND LINGER INTO
EARLY THURSDAY MORNING. HAVE INCLUDED 90-100% POPS IN THE FORECAST
FOR WESTERN WI...EASTERN/SOUTHERN MN WEDNESDAY AFTERNOON WHICH IS
PROBABLY OUR BEST WINDOW FOR RAIN IN THESE AREAS. STILL
PREDOMINATELY A LIQUID PRECIP SCENARIO OUTSIDE OF WEST CENTRAL MN
WHERE MORE OF A MIX CAN BE EXPECTED.
WITH A STATIONARY BOUNDARY STRETCHED OUT ACROSS THE
AREA TODAY...WIDESPREAD LIGHT FOG WITH AREAS OF DENSE FOG CAN BE
EXPECTED THIS MORNING. THE DENSE FOG ADVISORY ENDS AT 15Z AND
THIS STILL SEEMS REASONABLE GIVEN THE WIND INCREASES SLIGHTLY OUT
OF THE SOUTHEAST LATE THIS MORNING. ALSO...SOMETIMES THE ADVECTION
OF HIGH CLOUDS OVER THE FOG AND STRATUS CAN HELP TO BREAK UP
THICKER FOG AND WE`LL ALSO HAVE THAT AS WELL THIS MORNING.
OTHERWISE...THERE ARE STRATUS CLOUDS AS FAR AS THE EYE CAN SEE WITH
VERY FEW BREAKS SHOWING UP ON MY ENTIRE REGIONAL SATELLITE LOOP
THIS MORNING. THIS MEANS TEMPERATURES WILL NOT DRIFT MUCH FROM
WHERE THEY ARE NOW. THE DIFFERENCE BETWEEN THE HIGH AND LOW AT THE
MINNEAPOLIS AIRPORT YESTERDAY WAS 4 DEGREES AND THERE HAS BEEN
ABOUT 15-20 HOUR PERIOD WHERE MANY SITES ACROSS THE AREA HAVE ONLY
CHANGED A DEGREE OR TWO. SAME STORY TONIGHT...WHICH IS GOOD NEWS
FOR MANY LOCATIONS...BECAUSE MOST LOCATIONS WILL BE ABOVE FREEZING
WHEN THE RAIN BEGINS.
PER THE PAST COUPLE SREF SOLUTIONS...BEST CHANCE FOR A
SNOW/FREEZING RAIN MIXTURE LOOKS TO BE FROM NORTH CENTRAL NEBRASKA
INTO WEST CENTRAL MINNESOTA. LOCATIONS IN WEST CENTRAL MN HAVE
DEWPOINTS IN THE MID 20S AND TEMPS IN THE UPPER 20S TO LOWER 30S
THIS MORNING. ALTHOUGH AS SOUTHEASTERLY FLOW INCREASE WE WILL SEE
WEAK WARM AIR ADVECTION...SOME OF THESE SITES WILL IMPROVE BY A
FEW DEGREES TODAY. HOWEVER...AREAS ALONG OR NORTHWEST OF A LINE
FROM MONTEVIDEO...TO SAUK CENTRE...TO LITTLE FALLS HAVE THE
POTENTIAL TO SEE SMALL ICE/SNOW ACCUMULATIONS LATE TONIGHT OR
EARLY WEDNESDAY MORNING. BESIDES THE NAM...WHICH IS STRONGER AND
FASTER WITH THIS SYSTEM...THERE IS FAIRLY DECENT AGREEMENT AMONGST
THE UKMET/GFS/ECMWF WITH THE 42-54HR FORECAST. THE 13.00Z NAM HAD
A VERY IMPRESSIVE STRIPE OF SNOW ACROSS WEST CENTRAL MN...WITH A
RUN TOTAL SNOW ACCUM OF 10-16" IN LOCATIONS NEAR ALEXANDRIA. THE
13.06 RUN HAS BACKED OFF ON TOTALS...BUT STILL HAS A HEALTHY 2-5"
SNOWBAND. THE NAM SEEMS TO HOT WITH ITS INITIALIZATION WITH 500MB
HEIGHTS ROUGHLY 60M TOO LOW RIGHT OUT OF THE GATE. THERE IS
LIGHTNING ALONG THE WEST COAST...SO IT`S CERTAINLY A DYNAMIC
SYSTEM...JUST THINK THE NAM IS TOO AGGRESSIVE. MUCH LESS SNOW IS
FORECAST IN THE OTHER GUIDANCE. I GUESS I`M NOT TOO CONCERNED
ABOUT THE FREEZING RAIN GETTING OUT OF HAND GIVEN THAT TEMPS WILL
BE NEAR FREEZING AND THE BULK OF THE PRECIP SHOULD FALL IN
SOUTHEAST MN AND WESTERN WI. IT WILL STILL HAVE TO BE MONITORED
FOR A FREEZING RAIN ADVISORY.
THE ONLY OTHER CONCERN IN THE EXPECTED RAIN AREAS OF SOUTHERN MN
AND WESTERN WI IS DUE TO THE PRESENCE OF WEAK STABILITY AND EVEN
THE HINT OF ELEVATED INSTABILITY. BEST LI OF NEAR ZERO COMES
RIGHT UP TO THE MN/IA WEDNESDAY AFTERNOON. DES MOINES OFFICE HAS
ISOLATED THUNDER IN THE FORECAST. ALTHOUGH THE FORECAST SOUNDINGS
SHOW A PRETTY DEEP WARM LAYER AND SURFACE TEMPS THAT WILL AT LEAST
BE IN THE MID 30S...IT SEEMS HARD TO GET CONVECTIVE SHOWERS IN MID
DECEMBER WITHOUT SOME CHANGE OVER TO ICE PELLETS. LEFT ALL RAIN IN
THE GRIDS FOR NOW...BUT IT`S SOMETHING TO WATCH.
IN THE EXTENDED...SPLIT FLOW PATTERN SUGGESTS THE MERCURY WONT BE
KEPT DOWN TOO LONG AFTER A SHOT OF COOLER AIR ON THURSDAY AND
FRIDAY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/CLF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
310 PM MST TUE DEC 13 2011
.SHORT TERM...VALID FOR WED AND THU...
AREA OF STRATUS IN OUR EAST SLOW TO ERODE...AND AS OF 22Z LINGERS
FROM FORSYTH TO MILES CITY AND BAKER DOWN TO ALZADA...AND UP THE
TONGUE RIVER VALLEY AS WELL BUT SHERIDAN HAS BEGUN TO CLEAR OUT
OVER THE LAST HOUR. LOW LEVEL MOISTURE ACROSS OUR EAST WILL
GRADUALLY SCOUR OUT TONIGHT AS LATEST RUC ANALYSIS ALREADY SHOWS
INCREASED WESTERLY 850MB FLOW. THAT BEING SAID...SFC TROF ITSELF
REMAINS AT BIT EAST OF BILLINGS AND WE COULD SEE STRATUS LINGER
AND/OR SEE A LITTLE FOG DEVELOP EAST OF THIS TROF TONIGHT...
ESPECIALLY AS DEWPTS REMAIN IN THE UPPER TEENS AND LOWER 20S. HAVE
ADDED PATCHY FOG TO OUR EAST BUT WOULD EXPECT IT TO HAVE ERODED
COMPLETELY BY AROUND 12Z PER COLD FROPA AND ASSOCIATED WIND SHIFT
TO WESTERLY OVER TIME.
WEAK UPPER TROF REMAINS OVER EASTERN MONTANA...BUT UPSTREAM
SHORTWAVE IN SOUTHERN BRITISH COLUMBIA WILL BE A MINOR PLAYER AS
IT CLIPS THE AREA TOMORROW. SHOULD SEE SCATTERED SNOW SHOWERS OVER
THE MOUNTAINS BUT WILL KEEP POPS AT SLIGHT CHANCE FOR THE PLAINS
AS FORCING IS QUITE WEAK WITH DRY LOW LEVELS. OTHERWISE WILL SEE A
MODEST INCREASE IN SW-W THEN NW WINDS LATE TONIGHT AND TOMORROW
WITH THE FRONTAL PASSAGE.
AFTER A BRIEF BREAK IN THE WEATHER WEDNESDAY NIGHT...NEXT PACIFIC
WAVE WILL BEGIN TO IMPACT US THURSDAY. THIS WAVE WILL BE MORE
DYNAMIC BUT BRUNT OF ENERGY WILL DRIVE THROUGH THE GREAT BASIN
TOWARD THE FOUR CORNERS REGION...LEAVING WEAKER NORTHERN BRANCH
FORCING FOR US. THIS FORCING WILL BE COMPOSED OF SOME MID LEVEL
FRONTOGENESIS WHICH SHOULD FAVOR OUR NORTH TO NORTHEAST PARTS
INITIALLY ON THURSDAY...THEN UPPER TROF PASSAGE AND INSTABILITY
LATE THURSDAY AND THURSDAY NIGHT...DURING WHICH MODELS SHOW FAIR
Q-VECTOR CONVERGENCE. SHOULD AT LEAST SEE A QUICK COUPLE INCHES OF
SNOW FOR THE MOUNTAINS. POTENTIAL EXISTS FOR A LITTLE ACCUMULATION
FOR THE LOWER ELEVATIONS AS WELL...MAINLY IN OUR EAST AND NW FLOW
UPSLOPE AREAS...BUT DO NOT ANTICIPATE HIGHLIGHT CRITERIA ANYWHERE
AT THIS TIME. AGAIN THIS IS DUE TO SPLITTING NATURE OF THIS
PACIFIC ENERGY.
NO EXTREME TEMPS COMING IN THE NEXT COUPLE DAYS WITH COLD FROPA
TOMORROW AND AGAIN THURSDAY NIGHT NOT ABLE TO TAP INTO ANYTHING
TOO COLD...WITH ARCTIC AIR REMAINING TRAPPED WELL TO OUR NORTH.
TEMPS WILL REMAIN NEAR MID DECEMBER NORMALS.
JKL
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
THE GOING FORECAST CONTINUES TO BE IN GOOD SHAPE...SO DECIDED TO
ONLY MAKE MINOR TWEAKS IN A FEW AREAS.
MAIN JET ENERGY STAYS WELL TO THE NORTH OF THE FORECAST AREA FOR
MOST OF THE EXTENDED PERIOD...KEEPING THE REALLY COLD AIR LOCKED
UP IN NORTHERN CANADA.
FRIDAY AND SATURDAY...A FAIRLY FLAT UPPER LEVEL RIDGE BUILDS INTO
THE REGION FROM THE WEST. WEAK SHORTWAVE ENERGY SLIDES EASTWARD
ALONG THE TOP OF THE RIDGE...BUT WITH A MAINLY DRY NW FLOW
ALOFT...THIS SHORTWAVE ENERGY IS ONLY EXPECTED TO GENERATE SOME
MID AND HIGH CLOUDS. AT THE SURFACE...WINDS WILL BE GUSTY ACROSS
THE WEST AS THE PRESSURE GRADIENT TIGHTENS FRIDAY INTO EARLY
SATURDAY IN RESPONSE TO HIGH PRESSURE BUILDING INTO IDAHO.
MODELS ARE IN DISAGREEMENT SUNDAY INTO MONDAY. MUCH LIKE
YESTERDAYS 12Z RUN THE ECMWF PUSHES A STRONG COLD FRONT WITH SNOW
SHOWERS THROUGH THE REGION SUNDAY INTO EARLY MONDAY...THEN A DRY
NW FLOW TAKES OVER. AT THE SAME TIME...THE GFS DOES NOT BRING THE
COLD FRONT IN UNTIL AFTER THE ECMWF...THEN DRIVES A SHORTWAVE WITH
WIDELY SCATTERED SNOW SHOWER ACTIVITY THROUGH THE REGION LATE
MONDAY. AGAIN TODAY...OPTED NOT TO REALLY CHANGE THE SUNDAY/MONDAY
FORECAST MUCH DUE TO THE MODEL DISCREPANCIES.
TUESDAY/TUESDAY NIGHT RIDGING BUILDS BACK IN FROM THE
WEST...KEEPING THE AREA DRY.
AS FAR AS TEMPERATURES ARE CONCERNED...THEY WILL STAY AT OR ABOVE
NORMAL FOR MOST OF THE EXTENDED PERIOD. TRENDED TOWARDS BETTER
PERFORMING TEMP GUIDANCE...BCCONSRAW AND BCCONSALL FOR DAYTIME HIGHS
AND CONSALL FOR OVERNIGHT LOWS. STC
&&
.AVIATION...
MVFR/IFR CONDITIONS WILL CONTINUE FROM KMLS EAST...DUE TO LOW
CEILINGS...INTO THE OVERNIGHT HOURS. WEST NORTHWEST WINDS WILL
PICK UP ACROSS THE EAST WEDNESDAY MORNING AS A FRONT PASSES.
KSHR...KBIL AND KLVM WILL REMAIN VFR THROUGH TONIGHT. INTERMITTENT
MVFR CONDITIONS IN LOW CEILINGS/SNOW SHOWERS WILL BE POSSIBLE FROM
WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FROM KSHR AND KBIL
WEST. GUSTY WINDS WILL BE POSSIBLE OVERNIGHT FROM KBIL WEST TO
KLVM. CHURCH/STC
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 025/038 021/033 019/034 021/045 027/045 024/038 021/038
02/J 12/S 31/B 00/U 01/B 21/B 11/U
LVM 023/037 025/033 017/035 016/044 022/044 020/039 015/037
02/J 13/S 41/B 00/N 12/J 22/J 11/B
HDN 015/038 016/033 015/035 015/042 021/045 020/039 016/040
02/J 12/S 31/B 00/U 01/B 22/J 11/B
MLS 015/033 011/028 017/031 017/039 021/041 021/034 017/035
02/J 12/S 41/B 00/B 01/B 11/B 11/B
4BQ 015/035 013/032 017/034 015/041 021/043 020/037 017/039
02/J 12/S 51/B 00/U 01/B 21/B 11/B
BHK 013/032 009/025 015/026 015/039 021/040 018/033 016/035
02/J 12/S 51/B 00/B 01/B 11/B 11/B
SHR 014/036 012/033 018/031 016/042 023/042 021/035 015/038
02/J 12/S 42/J 00/U 01/B 22/J 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1124 AM CST TUE DEC 13 2011
.AVIATION...18Z KGRI TAF. LIFR CONDITIONS TO CONTINUE THROUGH MUCH
OF THE CURRENT TAF PERIOD. STRATUS WITH CEILINGS NEAR 200FT AGL
AND VISIBILITY RESTRICTIONS NEAR 1/2SM IN FOG WILL PERSIST THROUGH
16Z WEDNESDAY. THE PASSAGE OF A SURFACE FRONT WILL ALLOW LOW LEVEL
DRY AIR ADVECTION TO INFILTRATE THE AREA TOWARDS THE END OF THE
TAF PERIOD...ALLOWING FOR IMPROVING VISIBILITIES AND RISING
CEILINGS...AS WELL AS A CHANGE IN LOW LEVEL WIND DIRECTION.
&&
.PREV DISCUSSION... /ISSUED 609 AM CST TUE DEC 13 2011/
SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER LONG/CHALLENGING
NIGHT...MOSTLY SPENT FINE TUNING HOURLY SURFACE TEMPERATURE
TRENDS DURING THE NEXT 12-18 HOURS...AND RESULTANT PRECIP TYPE
FOR THE ONGOING HEADLINES. LOCALLY DENSE FOG IS ALSO ADDING TO THE
ONGOING FUN.
THE SHORT STORY FOR TODAY IS THAT THE INHERITED WINTER WEATHER
ADVISORIES FOR LIGHT ICING/LIGHT FREEZING RAIN WERE LEFT LARGELY
UNCHANGED. ONLY TWEAKS WERE TO ADD FILLMORE COUNTY TO THE SEGMENT
THAT EXPIRES AT NOON...AND TO DROP ROOKS COUNTY GIVEN THAT NEARBY
AUTOMATED OBS CONFIRM THAT TEMPS IN THAT AREA ARE GENERALLY 33-37
DEGREES...AND SHOULDN/T DROP ANY FARTHER. OTHER COUNTIES ON THE
EXTREME SOUTHERN EDGE SUCH AS PHILLIPS/SMITH ARE LIKELY MARGINAL
AS WELL...BUT AT LEAST NORTHERN EDGES COULD PICK UP SOME LIGHT
FREEZING DRIZZLE AND WANTED TO KEEP THEM IN. AS
MENTIONED...LOCALLY DENSE TO NEAR-DENSE ALSO CONTINUES TO DEVELOP
ACROSS PARTS OF THE CWA...AND FORESEE THIS BECOMING MORE AND MORE
OF AN ISSUE DURING THE NEXT SEVERAL HOURS. ISSUED A STAND-ALONE
DENSE FOG ADVISORY FOR ROOKS COUNTY KS...BUT OPTED TO KEEP IT
SIMPLE FOR THE MAJORITY OF THE CWA AND INCLUDE FOG HAZARDS IN THE
TEXT OF THE WINTER WEATHER ADVISORIES. THE HANDFUL OF COUNTIES IN
THE SOUTHERN CWA STILL UNDER NO HEADLINE MAY ULTIMATELY NEED ADDED
TO A DENSE FOG HEADLINE IF THINGS WORSEN...BUT AT LEAST FOR NOW
THESE COUNTIES SEEM TO HAVE VISIBILITIES SAFELY ABOVE ADVISORY
CRITERIA.
SO...FOR THE MOST PART THINGS STARTING TO UNFOLD AS
EXPECTED...WITH AT LEAST PATCHY AREAS OF LIGHT DRIZZLE/FREEZING
DRIZZLE GETTING UNDERWAY PER RADAR RETURNS AND GROUND TRUTH HERE
AT THE WFO. HOWEVER...AM NOT AWARE OF ANY SIGNIFICANT IMPACTS YET
AT THIS TIME. MOVING FORWARD INTO THE DAY...CONFIDENCE IN SEEING
WIDESPREAD MEASURABLE PRECIP HAS WANED FROM 24 HOURS AGO GIVEN
LATEST TRENDS OF RUC/NAM/HRRR KEEPING MOST LEGITIMATE RAIN SOUTH
OF THE CWA. STILL...INCREASING LOW LEVEL ISENTROPIC LIFT SHOULD BE
MORE THAN SUFFICIENT FOR CONTINUED DEVELOPMENT OF FOG AND AT LEAST
TRACE DRIZZLE/FREEZING DRIZZLE FOR SEVERAL HOURS IN MOST AREAS.
TOTAL ICE ACCUMULATIONS WITHIN THE ADVISORY AREAS HAVE BEEN
TRIMMED A BIT...NOW RANGING FROM A TRACE ALONG THE SOUTHERN FRINGE
TO MAYBE 5 HUNDREDTHS OF AN INCH OR SO IN NORTHWEST COUNTIES.
SPENT A LOT OF TIME FINE TUNING SURFACE TEMP TRENDS...LEANING
HEAVILY ON THE RUC AND HOURLY GFS LAMP GUIDANCE. TRENDS ON THE
GRADUAL SOUTH TO NORTH WARMING ABOVE FREEZING HAVEN/T CHANGED MUCH
FROM PREVIOUS THINKING...AND AS A RESULT SAW NO REASON TO CHANGE
THE CURRENT BREAKDOWN OF THE WINTER WEATHER ADVISORY...WITH
SEVERAL COUNTIES SOUTHEAST OF A FULLERTON TO ALMA LINE LIKELY DONE
WITH ANY ICING THREAT BY NOON AT THE LATEST...WHILE NORTHWEST
COUNTIES REMAIN UNDER THE GUN WELL INTO THE AFTERNOON. AGAIN...NOT
LOOKING AT MUCH ICE ACCUMULATION..ESPECIALLY MEASURABLE...BUT
EASILY ENOUGH TO CAUSE PROBLEMS ON UNTREATED SURFACES.
AS FOR DENSE FOG/POTENTIALLY DENSE FOG...COULD EASILY FORESEE
ISSUES LASTING WELL INTO THE OVERNIGHT HOURS...AND WILL DEFER TO
DAY SHIFT TO POSSIBLY ISSUE/EXTEND FOG HEADLINES AS NEW TRENDS
EMERGE. FOR NOW...WANTED AS MUCH FOCUS AS POSSIBLE TO BE ON LIGHT
ICING CONCERNS. DIDN/T CHANGE HIGH TEMPS TODAY MUCH...AIMING FOR A
GRADIENT FROM LOW-MID 30S NORTHWEST TO LOW-MID 40S SOUTHEAST.
BETTER CHANCES FOR LEGITIMATE MEASURABLE RAIN ARRIVES TONIGHT AS
PRIMARY MID LEVEL SHORTWAVE APPROACHES FROM NEW MEXICO...AND UPPER
JET DYNAMICS/DIFFLUENCE INCREASE. KEPT POPS HIGH
TONIGHT...ESPECIALLY ACROSS THE SOUTHEAST 1/2 OR SO WITH 70-90
PERCENTS. ALTHOUGH NOT EXPECTING WIDESPREAD LIGHTNING STRIKES...AT
LEAST 100-200 J/KG MUCAPE APPEARS SUFFICIENT FOR AT LEAST ISOLATED
THUNDERSTORMS...AND LEFT THIS MENTION INTACT ACROSS GENERALLY THE
SOUTHEAST 1/2 OF THE CWA. PRONOUNCED CONTINUED LOW LEVEL WARM AIR
ADVECTION SHOULD ALLOW TEMPS TO SLOWLY RISE OVERNIGHT...AND ONLY
THE EXTREME NORTHWEST FRINGES OF THE CWA SHOULD REGISTER TEMPS AT
OR BELOW FREEZING FOR A FEW HOURS AFTER SUNSET. UNLESS SOMETHING
LINGERS FOR A FEW HOURS FAR NORTHWEST...ICING ISSUES SHOULD BE LARGELY
OVER BY DARK.
WEDNESDAY...THE 00Z ECMWF/GFS ARE IN DECENT AGREEMENT TRACKING THE
MAIN SHORTWAVE DIRECTLY ACROSS THE PLAINS...WITH A ROUGHLY 1006MB
SFC LOW CENTERED OVER NORTH CENTRAL KS AT 18Z BEFORE ZIPPING
NORTHEAST. A MID LEVEL DRY SLOT COULD BRING PRECIP TO A FAIRLY
EARLY END ESPECIALLY IN SOUTHWEST ZONES...AND HAVE TRENDED POPS
DOWN ACCORDINGLY DURING THE DAY. WHILE THUNDER WAS NOT INCLUDED
FOR THE DAYTIME HOURS...COULD SEE SOME INSTABILITY LURKING IN
PARTS OF THE AREA...AND A FEW RUMBLES NOT OUT OF THE QUESTION.
HAVE QUITE A HIGH TEMP GRADIENT IN PLACE...RANGING FROM MID 30S
AROUND ORD NEB...TO MID 50S NEAR BELOIT KS.
WED EVENING...PRECIP SHOULD COME TO A QUICK END IN THE EAST AS THE
WAVE DEPARTS...AND LINGERED A SLIGHT POP FOR RAIN/SNOW IN
NORTHEAST ZONES THROUGH MIDNIGHT...BUT ITS VERY POSSIBLE THAT
EVERYTHING IS ALREADY OVER BY 00Z. QUIET AND DRY CONDITIONS THEN
ANTICIPATED WED NIGHT THROUGH THURSDAY NIGHT...AS A SURFACE RIDGE
AXIS MOVES ACROSS THE AREA. KEPT HIGHS THURSDAY SIMILAR TO
PREVIOUS FORECAST WITH MOST PLACES BETWEEN 34-40. LOWERED LOWS
THURS NIGHT WITH EXPECTATION OF LIGHT WINDS/CLEAR SKIES...WITH
MOST AREAS AT LEAST DOWN INTO THE UPPER TEENS.
LONG TERM...12Z FRIDAY THROUGH MONDAY...A RELATIVELY QUIET WEATHER
PATTERN CONTINUES TO BE IN STORE FOR THE END OF THE WORK WEEK AS A
SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING
ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING WEATHER MAKER.
UNDER THIS PATTERN...NEAR ZONAL TO NORTHWESTERLY FLOW ALOFT WILL
CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS
AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN
DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE
EXTENDED WHEN THE LOW ACROSS THE DESERT SOUTHWEST EJECTS INTO THE
PLAINS. GLOBAL MODELS ARE BEGINNING TO COME INTO BETTER AGREEMENT
WITH THE HANDING OF THIS CUTOFF LOW PRESSURE SYSTEM...WITH THE LOCAL
AREA NOW EXPECTED TO BE JUST NORTHWEST OF THE TRAJECTORY OF THIS LOW
PRESSURE SYSTEM AS IT EJECTS INTO THE PLAINS EARLY NEXT
WEEK...ALBEIT GFS REMAINS SLIGHTLY FURTHER WEST WHICH COULD HAVE A
LARGE IMPACT ON LOCAL WEATHER. HOWEVER...SINCE GFS IS NOW TRENDING
CLOSER TO THE EUROPEAN...KEPT LOW POPS ACROSS THE AREA WHICH IS MORE
IN LINE WITH THE EC...AND KEPT A CHANCE OF BOTH RAIN AND SNOW AS
TEMPERATURE ALOFT INITIALLY WILL BE MORE FAVORABLE FOR RAIN...BUT
COOL DURING THE EVENT SUPPORTING A CHANCE FOR SOME SNOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ039-
040-046-047-060-061-072-073-082.
DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NEZ039-040-
046-047-060>062-072>075-082>084.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ041-048-049-
062>064-074-075.
KS...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR KSZ005-017.
&&
$$
AVIATION...BRYANT
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1224 PM CST TUE DEC 13 2011
.UPDATE...
BNA STILL DOWN BELOW 1SM AT THIS HOUR. WILL EXTEND THE DRIZZLE AND
FOG INTO THE AFTERNOON. DESPITE THE RADAR RETURN...PRECIP AMOUNTS
ARE VERY LIGHT ACROSS THE NW. WILL THEREFORE KEEP THE POPS WHERE
THEY ARE. OTW...TEMPS AND WINDS ARE ON TRACK. UPDATE OUT
SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 827 AM CST TUE DEC 13 2011/
UPDATE...
WEAK DISTURBANCE MOVING OVER MO AND WESTERN KY IS EXTENDING A BIT
FURTHER SE THAN THE MODELS HAVE INDICATED. WE DO HAVE REPORTS OF
DRIZZLE AND FOG ACROSS THE AREA. THE LATEST RUC SHOWS THE SLIGHT
POTENTIAL FOR MEASURABLE RAINFALL ACROSS OUR NW COUNTIES TODAY.
FURTHERMORE...CANNOT DISCOUNT THE 50 POP FOR CKV FROM THE MET.
WILL GO AHEAD AND UPDATE THE GRIDS AND INTRODUCE A LOW CHANCE OF
SHOWERS FOR OUR NW COUNTIES FOR TODAY. OTW...REMAINDER OF FCST IS
OK AS THE DRIZZLE AND FOG SHOULD CONTINUE THIS MORNING.
UPDATE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 634 AM CST TUE DEC 13 2011/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
SURFACE HIGH CENTERED OVER EASTERN OHIO THIS MORNING WITH STRONG UPPER
RIDGE BUILDING EASTWARD FROM MISSISSIPPI VALLEY.
GOOD ISENTROPIC LIFT ON 290 KELVIN SURFACE WORKING AROUND PERIPHERY
OF UPPER RIDGE EVIDENT IN LATEST MOSAIC LOOP AS LIGHT RAIN HAS
SPREAD INTO FAR WESTERN KY/TN AT DAYBREAK. BEST LIFT WILL REMAIN
WEST AND NORTH OF MY CWA TODAY. FOG...AND LOW CEILINGS WILL SHOW
IMPROVEMENT AS WE GO THROUGH THE MORNING AT BNA BECOMING VFR
DURING AFTERNOON WITH A RETURN LATE NIGHT. AT CSV FOG AND LOW
CEILINGS WILL IMPROVE BUT SLOWLY BECOMING VFR BY EARLY TO MID-
AFTERNOON BEFORE RETURNING TO IFR CONDITIONS DURING THE EVENING
AND CONTINUING OVERNIGHT.
BOYD
PREV DISCUSSION... /ISSUED 308 AM CST TUE DEC 13 2011/
DISCUSSION...
CLOUDY FOGGY NIGHT ACROSS THE MID STATE WITH A FEW AREAS REPORTING
SOME DENSE FOG AND EVEN SOME PATCHES OF DRIZZLE OCCURRING.
DESPITE THE CLOUDS AND FOG...SURFACE OBS SHOW TEMPERATURES IN THE
40S WHICH ARE AROUND 20 DEGREES WARMER THAN THIS TIME YESTERDAY.
THIS IS THE BEGINNING OF A PERIOD OF NEAR TO ABOVE NORMAL
TEMPERATURES WHICH WILL CONTINUE FOR AT LEAST THE NEXT WEEK.
FEW CHANGES HAVE BEEN MADE TO OVERALL FORECAST AS GUIDANCE
CONTINUES TO HAVE A GOOD CONSENSUS ON UPCOMING PATTERN. WATER
VAPOR IMAGERY SHOWS OUR NEXT WEATHER MAKER IN THE FORM OF AN
UPPER LEVEL LOW OFF THE SOUTHERN CALIFORNIA COAST. THIS SYSTEM IS
EXPECTED TO OPEN INTO A POSITIVELY TILTED TROUGH WHICH WILL ENTER
THE PLAINS ON WEDNESDAY AND REACH OUR REGION ON THURSDAY. AHEAD OF
THE SYSTEM...INCREASING WAA REGIME ALONG WITH WEAK RIDGING ALOFT
WILL ALLOW FOR A CONTINUED WARMING TREND TODAY INTO TOMORROW.
TEMPS WILL BE TEMPERED SOMEWHAT PER FORECAST SOUNDINGS AND TIME
HEIGHT PLOTS AS A STRONG INVERSION AROUND 850MB TRAPS LOW CLOUDS
OVER THE MID STATE TODAY...AND THICK CIRRUS MOVES OVER THE MID
STATE ON WEDNESDAY. NEVERTHELESS...HIGHS LOOK TO WARM INTO THE 50S
AREA WIDE TODAY AND WELL INTO THE 60S ON WEDNESDAY.
GFS/NAM/ECMWF IN EXCELLENT AGREEMENT ON AFOREMENTIONED TROUGH
FORCING A COLD FRONT INTO THE NORTHWESTERN CWA BETWEEN 06-12Z
WEDNESDAY NIGHT WHICH WILL MOVE ACROSS THE ENTIRE CWA ON
THURSDAY...WITH WIDESPREAD SHOWERS EXPECTED. ADDED A MENTION OF
TSTORMS AS FORECAST SOUNDINGS SHOW K INDEX VALUES RISING INTO THE
MID 30S AND SOME WEAK ELEVATED INSTABILITY...ALTHOUGH MAJORITY OF
PRECIP WILL JUST BE SHOWERS. FRONT MOVES JUST SOUTH OF CWA AS A
SECONDARY WAVE MOVES ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY...BRINGING A SECOND ROUND OF RAIN TO ALL ZONES. DESPITE
FORECAST AREA BEING IN A POST FRONTAL AIRMASS...THERMAL PROFILES
WILL BE TOO WARM TO SUPPORT ANYTHING OTHER THAN RAIN.
AFTER PRECIP ENDS FRIDAY NIGHT...A BRIEF COOLDOWN WILL OCCUR OVER
THE WEEKEND WITH TEMPS FALLING BACK TO NEAR NORMAL LEVELS. GLOBAL
MODELS THEN DEPICT A SIMILAR SYSTEM AFFECTING THE MID STATE AGAIN
MONDAY AND TUESDAY OF NEXT WEEK WITH TEMPS WARMING ABOVE NORMAL
AND A COLD FRONT BRINGING ANOTHER ROUND OF SHOWERS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1204 PM CST TUE DEC 13 2011
.AVIATION...
FOR THE 18 UTC TAFS...AVIATION CONCERNS THIS CYCLE REVOLVE AROUND
CIGS/VISBYS THROUGH THE FIRST 18 H0URS OF THE FORECAST.
AREAS OF FOG CONTINUE TO HANG ON TOUGH ACROSS MUCH OF THE TX/OK
PANHANDLES...ESPECIALLY AT KAMA WHERE VISBYS HAVE BEEN BOUNCING
BETWEEN 1/4 TO 3/4 OF A MILE. THROUGH 00 UTC...HAVE VISBYS AT
3/4 MILE AT KAMA BUT SHOULD SEE CONDITIONS DETEIORATE TO 1/2 MILE
WITH RAIN SHOWERS AND FOG THIS EVENING. AS THE UPPER-LEVEL LOW LIFTS
TOWARD THE FOUR CORNERS REGION...UPPER-LEVEL LIFT WILL INCREASE
ACROSS THE AREA...WHICH WILL LEAD TO INCREASING RAIN CHANCES. LOW-
LEVEL MOISTURE WILL ALSO INCREASE...SO EXPET FOG TO THICKEN ONCE
AGAIN ACROSS THE PANHANDLES WITH VISBYS FALLING TO 1/2 MILE. ALONG
WITH THE FOG...HAVE INSERTED PREVAILING -RASH FOR TONIGHT BUT HAVE
OMITTED THUNDER MENTION AS CONFIDENCE IS TOO LOW THAT THUNDERSTORMS
WILL AFFECT THE TERMINALS. EXPECT SIMILAR CONDITIONS WRT FOG AND RAIN
POTENTIAL AT KDHT/KGUY TONIGHT. THE UPPER LOW WILL CONTINUE TO LIFT
ACROSS THE FOUR CORNERS REGION WEDNESDAY. A PACIFIC FRONT WILL START
TO ENTER THE NORTHERN PANHANDLES AT THE TAIL END OF THE FORECAST
PERIOD BUT EXPECT FROPA TO OCCUR AFTER 18 UTC. NONETHELESS RAIN
CHANCES SHOULD DIMINISH WED MORNING WITH CONDITIONS IMPROVING TO VFR
AT ALL THREE TERMINALS BY 16-17 UTC.
CLK
&&
.PREV DISCUSSION... /ISSUED 1034 AM CST TUE DEC 13 2011/
UPDATE...
REASON FOR UPDATE WAS TO EXPAND THE DENSE FOG ADVISORY OUT UNTIL 6 PM.
CALLS AROUND THE AREA REVEALED FOG CONTINUES TO HOLD ON ACROSS
PORTIONS OF THE SOUTHERN TEXAS PANHANDLE AND THE EASTERN TEXAS
PANHANDLE...WITH IMPROVING CONDITIONS IN THE CENTRAL TEXAS PANHANDLE.
THUS HAVE GONE EXPANDED THE DENSE FOG ADVISORY OUT UNTIL 6 PM BASED
ON THE LATEST RUC AND HRRR GUIDANCE...BUT OMITTED THE CENTRAL TEXAS
PANHANDLE DUE TO THE IMPROVED CONDITIONS. MAY HAVE TO EXPAND THE
DENSE FOG ADVISORY OUT EVEN FURTHER IN TIME BASED ON GUIDANCE AND
INCREASING LOW-LEVEL MOISTURE BUT WILL REVISIT THIS LATER IN TIME.
UPDATED PUBLIC PRODUCTS HAVE BEEN SENT.
CLK
PREV DISCUSSION... /ISSUED 716 AM CST TUE DEC 13 2011/
UPDATE...
LOWERED POPS FOR THE REMAINDER OF THE MORNING.
DISCUSSION...
BASED ON REGIONAL RADAR TRENDS AND LATEST RUC...NAM...AND HRRR
GUIDANCE...LOWERED POPS AREAWIDE FOR THIS MORNING. STILL THINKING
THE SOUTHEAST AREAS STAND TO SEE THE BEST CHANCE OF RAIN...BUT
AMOUNTS WILL BE LIGHT.
REGARDING THE DENSE FOG ADVISORY...WILL CONTINUE TO LET IT PLAY
OUT...ESPECIALLY WITH THE MORNING COMMUTE UNDERWAY. WE MADE ANOTHER
ROUND OF PHONE CALLS TO THE COUNTIES IN THE ADVISORY...AND MOST OF
THE AREAS SOUTH OF A LINE FROM FROM AMARILLO TO MIAMI TO WHEELER
CONTINUE TO SEE VERY LOW VISIBILITIES. IN FACT...THE SHERIFF/S
DEPARTMENTS IN WELLINGTON AND PANHANDLE ESTIMATED VISIBILITIES LESS
THAN 0.10 MILES. FOR THE COUNTIES IN THE ADVISORY NORTH OF THIS
LINE...THE FOG HAS GENERALLY LIFTED OR VISIBILITIES ARE BETWEEN 2 AND
5 MILES.
JACKSON
PREV DISCUSSION... /ISSUED 539 AM CST TUE DEC 13 2011/
AVIATION...
DENSE FOG AT THE DHT AND AMA TAF SITES SHOULD LAST THROUGH AT LEAST
MID MORNING BEFORE SLOWLY LIFTING INTO THE IFR RANGE FOR THE REST OF
THE DAY. VISIBILITIES WILL BE A LITTLE BETTER AT GUY...BUT THINK THE
CEILINGS THERE WILL STAY IN THE LIFR RANGE THROUGH MOST OF THE DAY.
RAIN SHOWER CHANCES WILL CONTINUE TO INCREASE THIS AFTERNOON AND
ESPECIALLY INTO THIS EVENING. A FEW THUNDERSTORMS MAY ALSO BE
POSSIBLE...BUT MOST OF THESE SHOULD REMAIN EAST OF THE TAF SITES.
CEILINGS AND VISIBILITIES ARE EXPECTED TO GO BACK DOWN AGAIN TONIGHT.
SOME MODELS EVEN WANT TO BRING DENSE FOG BACK AGAIN TO THE AMA AND
DHT TAF SITES. HAVE NOT GONE THAT LOW RIGHT NOW AS CONFIDENCE IS NOT
QUITE HIGH ENOUGH.
PREV DISCUSSION... /ISSUED 430 AM CST TUE DEC 13 2011/
DISCUSSION...
TODAY-TONIGHT: PHONE CALLS TO SHERIFF/S DEPARTMENTS AROUND THE AREA
INDICATE VISIBILITIES HAVE BEEN AT OR BELOW 1/4 MILE GENERALLY EAST
OF A LINE FROM AMARILLO TO BEAVER. ALTHOUGH SURFACE OBSERVATIONS
SHOW VISIBILITIES HAVE SLIGHTLY IMPROVED...WILL CONTINUE THE DENSE
FOG ADVISORY UNTIL 10 AM. CURRENTLY WATCHING SOME RAIN MOVE ACROSS
THE NORTHEAST PANHANDLES...AND THIS MAY BE ENOUGH TO MIX OUT THE
DENSE FOG. HOWEVER...VISIBILITIES MAY QUICKLY DETERIORATE ONCE THE
PRECIPITATION ENDS. IN FACT...SEEING THAT NOW AT AMARILLO AND EVEN
DALHART.
EXPECTING MUCH OF TODAY TO BE CLOUDY...COOL...AND SHOWERY. THINK THE
BEST CHANCE OF RAIN THIS MORNING WILL BE ACROSS THE NORTHWEST
PANHANDLES AND THE SOUTHEAST PANHANDLES. THE CENTRAL AREAS MAY
LARGELY BE VOID OF RAIN...BUT KEPT POPS IN SINCE THE AIR MASS WILL
REMAIN QUITE MOIST. RAINFALL AMOUNTS THIS MORNING ARE EXPECTED TO BE
LESS THAN 0.10" AREAWIDE.
BY THIS AFTERNOON...THE BEST CHANCE OF PRECIPITATION LOOKS TO BE
ACROSS THE EASTERN HALF OF THE PANHANDLES. DUE TO INCREASING LOW-
LEVEL MOISTURE AND STEEPENING LAPSE RATES AHEAD OF AN APPROACHING
UPPER TROUGH...FORECAST SOUNDINGS STILL INDICATE ENOUGH ELEVATED
INSTABILITY PRESENT TO WARRANT A MENTION OF THUNDERSTORMS SOUTH AND
EAST OF A LINE FROM DALHART TO GUYMON. NOT EXPECTING ANY STRONG OR SEVERE
STORMS DURING THIS TIME PERIOD. ONCE AGAIN...PRECIPITATION AMOUNTS
ARE EXPECTED TO BE LESS THAN 0.10" ACROSS THE ENTIRE AREA.
BY THIS EVENING...LARGE SCALE FORCING FOR ASCENT INCREASES
SUBSTANTIALLY. THINK SHOWERS AND THUNDERSTORMS ARE A REALLY GOOD BET
JUST ABOUT EVERYWHERE...BUT PARTICULARLY WEST OF A CLAUDE TO LIPSCOMB
LINE. AFTER MIDNIGHT...THINK THE BEST SHOWER AND THUNDERSTORM CHANCES
WILL BE EAST OF A LINE FROM GUYMON TO DALHART. NOT EXPECTING ANY
SEVERE WEATHER...BUT MAY SEE A FEW STRONG STORMS...PARTICULARLY
ACROSS THE SOUTHEAST TEXAS PANHANDLE BETWEEN 9 PM AND 3 AM. FORECAST
SOUNDINGS AND 03 UTC SREF GUIDANCE ARE SUGGESTING THE POSSIBILITY OF
MUCAPE VALUES AROUND 300 J/KG ACROSS THE SOUTHEAST TEXAS PANHANDLE.
WITH 0-6 KM SHEAR VALUES BETWEEN 70 AND 80 KT...SOME STORMS COULD
PRODUCE SMALL HAIL. SHOULD ALSO SEE SOME BENEFICIAL RAINFALL WITH
AMOUNTS POSSIBLY UP TO 0.50" OVERNIGHT.
WEDNESDAY: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE
FORECAST AREA DURING THE DAY....RESULTING IN DECREASING CHANCES FOR
PRECIPITATION. THERE STILL LOOKS TO BE JUST ENOUGH LINGERING LOW-
LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING
FOR A SLIGHT CHANCE OF SHOWERS. REMOVED THUNDERSTORMS FROM THE
FORECAST DURING THE MORNING AS ANY ELEVATED INSTABILITY SHOULD BE
EAST OF THE FORECAST AREA. THANKS TO THE DRY SLOT...FOLKS WILL BE
HAPPY TO SEE THE SUN MAKE A RETURN APPEARANCE. HIGH TEMPERATURES
SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY LOWER 60S AS STRONG
DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO
STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS.
FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW
/UP TO 775 MB/ AND WILL NOT BE ABLE TO TAP INTO THE HIGHER MOMENTUM
MID-LEVEL AIR. FORECAST SOUNDINGS ARE STILL SHOWING 30-35 KT FLOW AT
THE TOP OF THE BOUNDARY LAYER...BUT CONTINUED TO KEEP WINDS BELOW
ADVISORY CRITERIA. MET GUIDANCE CONTINUES ITS TREND OF DECREASING
THE WINDS...AND EVEN THOUGH THE MAV GUIDANCE /WHICH HAS BEEN RUNNING
TOO HIGH SINCE THIS SPRING/ STILL INDICATES LOW END ADVISORY CRITERIA
WINDS ACROSS THE SOUTHWEST TEXAS PANHANDLE...IT HAS ALSO TRENDED LOWER.
BIAS CORRECTED MAV GUIDANCE INDICATES WINDS WINDS AT OR BELOW 30 KT
ACROSS THE ENTIRE FORECAST AREA. THEREFORE...CONFIDENCE IS INCREASING
THAT A WIND ADVISORY WILL LIKELY NOT BE NEEDED. AS THE UPPER TROUGH
AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A
COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES DURING THE
EVENING WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS
THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE
PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE
UNDER 10 MPH BY MIDNIGHT THURSDAY.
THURSDAY-THURSDAY NIGHT: NO MAJOR CHANGES MADE DURING THIS TIME
PERIOD. MOSTLY SUNNY SKIES...LIGHT WINDS...SUB-SEASONAL TEMPS...AND
DRY CONDITIONS WILL PREVAIL AS HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI VALLEY BY FRIDAY.
BEYOND FRIDAY: CONFIDENCE CONTINUES TO REMAIN LOW SO VERY FEW CHANGES
WERE MADE TO THE FORECAST. THE GGEM APPEARS TO BE TOO FAR EAST WITH
THE UPPER LOW ON SATURDAY...SO IT WAS IGNORED FOR THIS FORECAST
PACKAGE. WITH THE SLOWER PROGRESSION OF THE CLOSED UPPER LOW SHOWN
BY THE ECMWF AND GFS...MOST OF THE WEEKEND MAY ACTUALLY BE DRY NOW.
SINCE THE MODELS MAY STILL HAVE SOME RUN-TO-RUN CONSISTENCY
ISSUES...DECIDED TO KEEP POPS IN THE FORECAST FROM SATURDAY NIGHT
ONWARD. IF THE SLOWER TREND CONTINUES...WE SHOULD BE ABLE TO
REMOVE POPS THROUGH AT LEAST SUNDAY MORNING. SUNDAY AFTERNOON AND
BEYOND IS WHEN THE FORECAST BEGINS TO BECOME EVEN MORE MUDDY. THE
DGEX AND GFS ARE FASTER WITH EJECTING THE UPPER LOW INTO THE CENTRAL
PLAINS MONDAY. MEANWHILE...THE ECMWF REMAINS MUCH SLOWER AND FARTHER
SOUTH WITH THE CLOSED LOW. STILL SEEING QUITE A BIT OF SPREAD IN THE
GEFS...ECMWF...AND CANADIAN ENSEMBLES. HOWEVER...STILL PREFER THE
ECMWF AS IT IS SUPPORTED BY THE ECMWF ENSEMBLE...CANADIAN
ENSEMBLE...AND JMA MODEL. BASED ON THIS...EXPECT PRECIPITATION TO
BEGIN SUNDAY NIGHT...SPREAD NORTHWARD DURING THE DAY ON MONDAY...AND
CONTINUE INTO MONDAY NIGHT. GIVEN THIS SCENARIO...ENVISION A MIX OF
RAIN AND SNOW SUNDAY NIGHT AND MONDAY MORNING ACROSS MOST OF THE
AREA. AS COLDER AIR BECOMES DEEPER BY MONDAY AFTERNOON...WOULD EXPECT
THE PRECIPITATION TYPE TO TRANSITION TO ALL SNOW. THIS SYSTEM WILL
HAVE TO BE WATCHED VERY CLOSELY AS IT HAS POTENTIAL TO BRING ANOTHER
ROUND OF WINTER WEATHER TO THE PANHANDLES.
JACKSON
FIRE WEATHER...
RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT
ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A
RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HEMPHILL...LIPSCOMB...POTTER...RANDALL...WHEELER.
OK...NONE.
&&
$$
05/03
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1034 AM CST TUE DEC 13 2011
.UPDATE...
REASON FOR UPDATE WAS TO EXPAND THE DENSE FOG ADVISORY OUT UNTIL 6 PM.
CALLS AROUND THE AREA REVEALED FOG CONTINUES TO HOLD ON ACROSS
PORTIONS OF THE SOUTHERN TEXAS PANHANDLE AND THE EASTERN TEXAS
PANHANDLE...WITH IMPROVING CONDITIONS IN THE CENTRAL TEXAS PANHANDLE.
THUS HAVE GONE EXPANDED THE DENSE FOG ADVISORY OUT UNTIL 6 PM BASED
ON THE LATEST RUC AND HRRR GUIDANCE...BUT OMITTED THE CENTRAL TEXAS
PANHANDLE DUE TO THE IMPROVED CONDITIONS. MAY HAVE TO EXPAND THE
DENSE FOG ADVISORY OUT EVEN FURTHER IN TIME BASED ON GUIDANCE AND
INCREASING LOW-LEVEL MOISTURE BUT WILL REVISIT THIS LATER IN TIME.
UPDATED PUBLIC PRODUCTS HAVE BEEN SENT.
CLK
&&
.PREV DISCUSSION... /ISSUED 716 AM CST TUE DEC 13 2011/
UPDATE...
LOWERED POPS FOR THE REMAINDER OF THE MORNING.
DISCUSSION...
BASED ON REGIONAL RADAR TRENDS AND LATEST RUC...NAM...AND HRRR
GUIDANCE...LOWERED POPS AREAWIDE FOR THIS MORNING. STILL THINKING
THE SOUTHEAST AREAS STAND TO SEE THE BEST CHANCE OF RAIN...BUT
AMOUNTS WILL BE LIGHT.
REGARDING THE DENSE FOG ADVISORY...WILL CONTINUE TO LET IT PLAY
OUT...ESPECIALLY WITH THE MORNING COMMUTE UNDERWAY. WE MADE ANOTHER
ROUND OF PHONE CALLS TO THE COUNTIES IN THE ADVISORY...AND MOST OF
THE AREAS SOUTH OF A LINE FROM FROM AMARILLO TO MIAMI TO WHEELER
CONTINUE TO SEE VERY LOW VISIBILITIES. IN FACT...THE SHERIFF/S
DEPARTMENTS IN WELLINGTON AND PANHANDLE ESTIMATED VISIBILITIES LESS
THAN 0.10 MILES. FOR THE COUNTIES IN THE ADVISORY NORTH OF THIS
LINE...THE FOG HAS GENERALLY LIFTED OR VISIBILITIES ARE BETWEEN 2 AND
5 MILES.
JACKSON
PREV DISCUSSION... /ISSUED 539 AM CST TUE DEC 13 2011/
AVIATION...
DENSE FOG AT THE DHT AND AMA TAF SITES SHOULD LAST THROUGH AT LEAST
MID MORNING BEFORE SLOWLY LIFTING INTO THE IFR RANGE FOR THE REST OF
THE DAY. VISIBILITIES WILL BE A LITTLE BETTER AT GUY...BUT THINK THE
CEILINGS THERE WILL STAY IN THE LIFR RANGE THROUGH MOST OF THE DAY.
RAIN SHOWER CHANCES WILL CONTINUE TO INCREASE THIS AFTERNOON AND
ESPECIALLY INTO THIS EVENING. A FEW THUNDERSTORMS MAY ALSO BE
POSSIBLE...BUT MOST OF THESE SHOULD REMAIN EAST OF THE TAF SITES.
CEILINGS AND VISIBILITIES ARE EXPECTED TO GO BACK DOWN AGAIN TONIGHT.
SOME MODELS EVEN WANT TO BRING DENSE FOG BACK AGAIN TO THE AMA AND
DHT TAF SITES. HAVE NOT GONE THAT LOW RIGHT NOW AS CONFIDENCE IS NOT
QUITE HIGH ENOUGH.
PREV DISCUSSION... /ISSUED 430 AM CST TUE DEC 13 2011/
DISCUSSION...
TODAY-TONIGHT: PHONE CALLS TO SHERIFF/S DEPARTMENTS AROUND THE AREA
INDICATE VISIBILITIES HAVE BEEN AT OR BELOW 1/4 MILE GENERALLY EAST
OF A LINE FROM AMARILLO TO BEAVER. ALTHOUGH SURFACE OBSERVATIONS
SHOW VISIBILITIES HAVE SLIGHTLY IMPROVED...WILL CONTINUE THE DENSE
FOG ADVISORY UNTIL 10 AM. CURRENTLY WATCHING SOME RAIN MOVE ACROSS
THE NORTHEAST PANHANDLES...AND THIS MAY BE ENOUGH TO MIX OUT THE
DENSE FOG. HOWEVER...VISIBILITIES MAY QUICKLY DETERIORATE ONCE THE
PRECIPITATION ENDS. IN FACT...SEEING THAT NOW AT AMARILLO AND EVEN
DALHART.
EXPECTING MUCH OF TODAY TO BE CLOUDY...COOL...AND SHOWERY. THINK THE
BEST CHANCE OF RAIN THIS MORNING WILL BE ACROSS THE NORTHWEST
PANHANDLES AND THE SOUTHEAST PANHANDLES. THE CENTRAL AREAS MAY
LARGELY BE VOID OF RAIN...BUT KEPT POPS IN SINCE THE AIR MASS WILL
REMAIN QUITE MOIST. RAINFALL AMOUNTS THIS MORNING ARE EXPECTED TO BE
LESS THAN 0.10" AREAWIDE.
BY THIS AFTERNOON...THE BEST CHANCE OF PRECIPITATION LOOKS TO BE
ACROSS THE EASTERN HALF OF THE PANHANDLES. DUE TO INCREASING LOW-
LEVEL MOISTURE AND STEEPENING LAPSE RATES AHEAD OF AN APPROACHING
UPPER TROUGH...FORECAST SOUNDINGS STILL INDICATE ENOUGH ELEVATED
INSTABILITY PRESENT TO WARRANT A MENTION OF THUNDERSTORMS SOUTH AND
EAST OF A LINE FROM DALHART TO GUYMON. NOT EXPECTING ANY STRONG OR SEVERE
STORMS DURING THIS TIME PERIOD. ONCE AGAIN...PRECIPITATION AMOUNTS
ARE EXPECTED TO BE LESS THAN 0.10" ACROSS THE ENTIRE AREA.
BY THIS EVENING...LARGE SCALE FORCING FOR ASCENT INCREASES
SUBSTANTIALLY. THINK SHOWERS AND THUNDERSTORMS ARE A REALLY GOOD BET
JUST ABOUT EVERYWHERE...BUT PARTICULARLY WEST OF A CLAUDE TO LIPSCOMB
LINE. AFTER MIDNIGHT...THINK THE BEST SHOWER AND THUNDERSTORM CHANCES
WILL BE EAST OF A LINE FROM GUYMON TO DALHART. NOT EXPECTING ANY
SEVERE WEATHER...BUT MAY SEE A FEW STRONG STORMS...PARTICULARLY
ACROSS THE SOUTHEAST TEXAS PANHANDLE BETWEEN 9 PM AND 3 AM. FORECAST
SOUNDINGS AND 03 UTC SREF GUIDANCE ARE SUGGESTING THE POSSIBILITY OF
MUCAPE VALUES AROUND 300 J/KG ACROSS THE SOUTHEAST TEXAS PANHANDLE.
WITH 0-6 KM SHEAR VALUES BETWEEN 70 AND 80 KT...SOME STORMS COULD
PRODUCE SMALL HAIL. SHOULD ALSO SEE SOME BENEFICIAL RAINFALL WITH
AMOUNTS POSSIBLY UP TO 0.50" OVERNIGHT.
WEDNESDAY: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE
FORECAST AREA DURING THE DAY....RESULTING IN DECREASING CHANCES FOR
PRECIPITATION. THERE STILL LOOKS TO BE JUST ENOUGH LINGERING LOW-
LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING
FOR A SLIGHT CHANCE OF SHOWERS. REMOVED THUNDERSTORMS FROM THE
FORECAST DURING THE MORNING AS ANY ELEVATED INSTABILITY SHOULD BE
EAST OF THE FORECAST AREA. THANKS TO THE DRY SLOT...FOLKS WILL BE
HAPPY TO SEE THE SUN MAKE A RETURN APPEARANCE. HIGH TEMPERATURES
SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY LOWER 60S AS STRONG
DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO
STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS.
FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW
/UP TO 775 MB/ AND WILL NOT BE ABLE TO TAP INTO THE HIGHER MOMENTUM
MID-LEVEL AIR. FORECAST SOUNDINGS ARE STILL SHOWING 30-35 KT FLOW AT
THE TOP OF THE BOUNDARY LAYER...BUT CONTINUED TO KEEP WINDS BELOW
ADVISORY CRITERIA. MET GUIDANCE CONTINUES ITS TREND OF DECREASING
THE WINDS...AND EVEN THOUGH THE MAV GUIDANCE /WHICH HAS BEEN RUNNING
TOO HIGH SINCE THIS SPRING/ STILL INDICATES LOW END ADVISORY CRITERIA
WINDS ACROSS THE SOUTHWEST TEXAS PANHANDLE...IT HAS ALSO TRENDED LOWER.
BIAS CORRECTED MAV GUIDANCE INDICATES WINDS WINDS AT OR BELOW 30 KT
ACROSS THE ENTIRE FORECAST AREA. THEREFORE...CONFIDENCE IS INCREASING
THAT A WIND ADVISORY WILL LIKELY NOT BE NEEDED. AS THE UPPER TROUGH
AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A
COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES DURING THE
EVENING WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS
THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE
PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE
UNDER 10 MPH BY MIDNIGHT THURSDAY.
THURSDAY-THURSDAY NIGHT: NO MAJOR CHANGES MADE DURING THIS TIME
PERIOD. MOSTLY SUNNY SKIES...LIGHT WINDS...SUB-SEASONAL TEMPS...AND
DRY CONDITIONS WILL PREVAIL AS HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI VALLEY BY FRIDAY.
BEYOND FRIDAY: CONFIDENCE CONTINUES TO REMAIN LOW SO VERY FEW CHANGES
WERE MADE TO THE FORECAST. THE GGEM APPEARS TO BE TOO FAR EAST WITH
THE UPPER LOW ON SATURDAY...SO IT WAS IGNORED FOR THIS FORECAST
PACKAGE. WITH THE SLOWER PROGRESSION OF THE CLOSED UPPER LOW SHOWN
BY THE ECMWF AND GFS...MOST OF THE WEEKEND MAY ACTUALLY BE DRY NOW.
SINCE THE MODELS MAY STILL HAVE SOME RUN-TO-RUN CONSISTENCY
ISSUES...DECIDED TO KEEP POPS IN THE FORECAST FROM SATURDAY NIGHT
ONWARD. IF THE SLOWER TREND CONTINUES...WE SHOULD BE ABLE TO
REMOVE POPS THROUGH AT LEAST SUNDAY MORNING. SUNDAY AFTERNOON AND
BEYOND IS WHEN THE FORECAST BEGINS TO BECOME EVEN MORE MUDDY. THE
DGEX AND GFS ARE FASTER WITH EJECTING THE UPPER LOW INTO THE CENTRAL
PLAINS MONDAY. MEANWHILE...THE ECMWF REMAINS MUCH SLOWER AND FARTHER
SOUTH WITH THE CLOSED LOW. STILL SEEING QUITE A BIT OF SPREAD IN THE
GEFS...ECMWF...AND CANADIAN ENSEMBLES. HOWEVER...STILL PREFER THE
ECMWF AS IT IS SUPPORTED BY THE ECMWF ENSEMBLE...CANADIAN
ENSEMBLE...AND JMA MODEL. BASED ON THIS...EXPECT PRECIPITATION TO
BEGIN SUNDAY NIGHT...SPREAD NORTHWARD DURING THE DAY ON MONDAY...AND
CONTINUE INTO MONDAY NIGHT. GIVEN THIS SCENARIO...ENVISION A MIX OF
RAIN AND SNOW SUNDAY NIGHT AND MONDAY MORNING ACROSS MOST OF THE
AREA. AS COLDER AIR BECOMES DEEPER BY MONDAY AFTERNOON...WOULD EXPECT
THE PRECIPITATION TYPE TO TRANSITION TO ALL SNOW. THIS SYSTEM WILL
HAVE TO BE WATCHED VERY CLOSELY AS IT HAS POTENTIAL TO BRING ANOTHER
ROUND OF WINTER WEATHER TO THE PANHANDLES.
JACKSON
FIRE WEATHER...
RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT
ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A
RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HEMPHILL...LIPSCOMB...POTTER...RANDALL...WHEELER.
OK...NONE.
&&
$$
05/03
AREA FORECAST DISCUSSION
NWS SPOKANE WA
951 AM PST Tue Dec 13 2011
.SYNOPSIS...High pressure will be over the Inland Northwest for
through Wednesday. A weak wave will track through British Columbia
and may bring some light mountain snow showers today. A stronger and
more organized Pacific storm system will arrive Wednesday evening
and Thursday with the possibility of a chance of snow
accumulations down to the valley floors.
&&
.DISCUSSION...
Made minor changes to the forecast this morning. Stratus is
widespread across the low lands with tops to close to 5k ft.
Meanwhile moisture above 500mb has generated high clouds that are
moving into the region ahead of the advancing shortwave trough.
Weak lift associated with the advancing wave and helped deepen the
boundary layer, raising ceilings and generated light flurries and
spotty freezing drizzle. Anticipate the light precipitation threat
to wane through the afternoon as cloud decks continue to rise. The
HRR, NAM and RUC increase SE winds across the Palouse that may
help scour out the stratus and press it into the Columbia Basin.
Otherwise anticipate low clouds for much of the day and night.
/rfox.
&&
.AVIATION...
18Z TAFs...Stratus is widespread with IFR/MVFR CIGS on a slow and
gradual improving trend. Most TAF sites have VSBYS improved to
above 6 miles. The problem area will continue to be KGEG where the
IFR CIGS/VSBYS will continue through much of the day with only
slight improvements in VSBYS in the afternoon. Anticipate the MVFR
deck to lift from KLWS and KPUW late this afternoon and early
evening, but return temporarily overnight. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 21 31 25 33 21 / 10 10 0 60 60 10
Coeur d`Alene 32 22 33 26 33 24 / 10 10 10 70 60 10
Pullman 29 23 35 27 35 24 / 10 10 10 50 60 20
Lewiston 33 25 37 29 40 25 / 0 10 10 30 50 10
Colville 31 20 32 22 34 21 / 10 10 10 70 60 10
Sandpoint 31 22 32 24 33 23 / 10 10 10 70 70 10
Kellogg 31 22 32 25 31 24 / 10 10 10 60 70 20
Moses Lake 28 16 32 21 36 15 / 0 0 10 40 20 10
Wenatchee 29 23 32 26 36 24 / 0 0 10 60 20 10
Omak 31 18 32 21 36 18 / 10 0 10 70 30 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Air Stagnation Advisory until Noon PST Thursday for Central
Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse-
Lewiston Area-Northern Panhandle.
WA...Air Stagnation Advisory until Noon PST Thursday for East Slopes
Northern Cascades-Lower Garfield and Asotin Counties-Moses
Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan
Valley-Spokane Area-Upper Columbia Basin-Washington Palouse-
Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
327 PM CST TUE DEC 13 2011
.VERY SHORT TERM...
TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWED A DEEP TROUGH OVER THE
WESTERN U.S...WITH A LARGE PLUME OF MOISTURE STRETCHING FROM TEXAS
THROUGH NORTHERN MISSOURI. SHORTWAVE EJECTING OUT OF THE SW UPPER
LOW WILL BRING A SFC LOW FROM THE PLAINS THROUGH IOWA ON WED. FIRST
ROUND OF PRECIPITATION WILL BEGIN ALREADY TONIGHT ON THE NOSE OF THE
LOW LEVEL JET AND AN INITIAL WEAK SHORTWAVE OUT AHEAD OF THE MAIN
TROUGH. STRONG ISENTROPIC LIFT ALONG THIS SURGE OF WARM AND MOIST
AIR WILL ALLOW FOR MODERATE RAIN OVERNIGHT THROUGH EARLY WED
MORNING.
MODELS SLOWED DOWN THE ONSET OF THE PRECIP...SO BACKED OFF POPS A
BIT IN THE 03Z-06Z TIME RANGE. PRECIP FOR THE FIRST ROUND COULD
APPROACH A QUARTER INCH.
A LULL IN THE STEADY PRECIP IS EXPECTED DURING THE MORNING HOURS ON
WED. THE INITIAL WAA AND ISENTROPIC LIFT WILL BE TO THE NORTH OF THE
FORECAST AREA...AND THE WARM FRONTAL PRECIP WILL STILL BE SOUTH OF
THE WI/IL BORDER. DURING THIS LULL...THERE MAY BE SOME AREAS OF FOG
AND MUCH LOWER CLOUDS.
THEN THE SECOND ROUND OF PRECIP WILL COME IN EITHER LATE MORNING OR
EARLY AFTERNOON ON WED...TIMING STILL UNCERTAIN. STRONG DYNAMICS
WITH THIS SURGE OF MOISTURE...SINCE THE 500MB TROUGH AND SFC LOW
WILL BE APPROACHING...ALONG WITH THE SFC AND 850MB WARM FRONT. WITH
THE STRONG FORCING...ISOLATED THUNDER NOT OUT OF THE QUESTION. KEPT
THE SCHC THUNDER MENTION IN THE AFTERNOON. UP TO A HALF INCH OF RAIN
POSSIBLE WITH THIS SECOND ROUND. TEMPS EXPECTED TO RISE INTO THE
MID/UPPER 40S WITH THE FRONT LATE WED AFTERNOON.
.SHORT TERM...WEDNESDAY NIGHT THROUGH FRIDAY.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO
HIGH.
SOUTHERLY FLOW AHEAD OF THE SURFACE LOW BRINGS THERMAL RIDGE INTO
THE SOUTHEAST THAT WILL ALLOW TEMPERATURES TO CLIMB TO THE LOW 50S.
MAIN AREA OF PRECIPITATION WILL END FROM WEST TO EAST AFTER 06Z
THURSDAY WITH SUBSIDENCE BEHIND 500 MB AND SURFACE TROUGHS.
OMEGA AHEAD OF SECOND NORTHERN STREAM SHORT WAVE MAINLY FOCUSED TO
THE NORTH WITH THE STRONGEST 700-500MB FRONTOGENETIC RESPONSE DURING
THE DAY THURSDAY. COLDER AIR HOLDS OFF UNTIL PASSAGE OF THIS SECOND
WAVE...SO EXPECT ANY LINGERING PRECIPITATION THURSDAY TO BE VERY
LIGHT RAIN OR DRIZZLE...WITH DRYING IN THE DENDRITE GROWTH ZONE
PREVENTING CRYSTAL FORMATION AND SNOW. EARLY DAYTIME HIGH
TEMPERATURES AROUND 12-13Z THURSDAY THEN COOLING THROUGH THE DAY.
ANY LIGHT PRECIPITATION SHOULD END BY 18Z.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
SURFACE HIGH PRESSURE BUILDS OVER FOR THURSDAY NIGHT AND FRIDAY.
CLEARING SKIES THURSDAY NIGHT...BUT WINDS WILL TAKE A BIT LONGER TO
LIGHTEN/DECOUPLE OVERNIGHT. LOWS AROUND 20 NORTHWEST...TO MID 20S
ALONG THE LAKE. -5C TO -6C 925 MB TEMPERATURES SUPPORT LOW TO MID 30
HIGHS FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FORECAST CONFIDENCE LOW
TO MEDIUM.
NORTHWEST TO SOUTHEAST MOVING SHORT WAVE CROSSES REGION FRIDAY
NIGHT/SATURDAY...BUT DRY LOWER LAYERS WILL PREVENT
MEASURABLE...THOUGH A FEW FLURRIES ARE POSSIBLE. WILL LEAVE ANY
PRECIPITATION MENTION OUT FOR NOW. DRY NORTHWEST FLOW WITH NORMAL
TEMPERATURES SATURDAY...BEGINS TO BACK WEST SUNDAY AND THEN
SOUTHWEST MONDAY AS NEXT SYSTEM EJECTS OUT OF THE SOUTHWEST U.S.
INTO THE CENTRAL PLAINS. WHILE MODELS DIFFER ON EXACTING
DETAILS...EARLY TREND IS TO TAKE SURFACE LOW ACROSS ILLINOIS AND
INDIANA MONDAY NIGHT/TUESDAY...WITH SOUTHERN WISCONSIN ON THE
NORTHERN EDGE OF THE PRECIPITATION SHIELD. WARMTH PUSHING BACK NORTH
AHEAD OF LOW WILL BRING A MAINLY RAIN/SNOW MIX...CHANGING TO ALL
SNOW AFTER LOW PASSAGE. WILL HAVE TO WATCH FOR ACCUMULATING SNOW
POTENTIAL IF PROFILE TEMPERATURES COO MORE THAN CURRENTLY
INDICATED.
&&
.AVIATION/00Z TAFS/...VFR CIGS WILL SLOWLY LOWER AS SOUTH WINDS
SLOWLY INCREASE LOW LEVEL MOISTURE THIS EVENING. SLOWED THE TIMING
OF THIS LOWERING TO EARLY EVENING. MVFR CIGS WILL DEVELOP FROM WEST
TO EAST ACROSS THE CWA DURING THE AFTERNOON INTO THE EARLY EVENING.
RAIN VIA WARM...MOIST ADVECTION WILL THEN ARRIVE AT THE TAF SITES BY
AROUND MIDNIGHT AND CONTINUE INTO WED. CIGS WILL FALL TO LIFR WITH
THE RAIN AND SATURATION OF THE LOW LEVEL ATMOSPHERE WHILE VSBYS WILL
FALL TO IFR.
THERE SHOULD BE A PERIOD OF TIME WED MORNING WHERE THERE IS A LULL
IN THE STEADY RAIN...WHICH WOULD ACTUALLY DIMINISH VISIBILITY AND
LOWER THE CEILING HEIGHTS. NOT SURE OF EXACT TIMING OF THIS
LULL...THEN RAIN WILL INCREASE ONCE AGAIN EARLY WED AFTERNOON AS THE
MAIN UPPER AND SFC LOW APPROACH SOUTHERN WI. THE SECOND ROUND OF
RAIN IS EXPECTED TO BE HEAVIER THAN THE FIRST...AND THE STRONG
FORCING SHOULD ALLOW FOR SOME ISOLATED THUNDER.
&&
.MARINE...INCREASING SOUTHERLY WINDS WILL ALLOW FOR BUILDING WAVES
TO NEAR-SMALL CRAFT ADVISORY CRITERIA WED AFTERNOON. WAVE MODEL FCST
WAVE HEIGHTS UP TO 3 TO 4 FEET...SO HELD OFF ON ISSUING A SMALL CRAFT
ADVY. WEST WINDS BEHIND THE DEPARTING LOW ON THU WILL INCREASE...AND
WIND GUSTS TO 25 KNOTS ARE POSSIBLY/LIKELY WITH THE COLD AIR
ADVECTION. SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC
WEDNESDAY NIGHT THROUGH TUESDAY...REM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1217 PM CST TUE DEC 13 2011
.UPDATE...
WIDESPREAD CLOUDS ACROSS THE ENTIRE UPPER MIDWEST TODAY DUE TO
PERSISTENT BUT WEAK WARM AIR ADVECTION...THE LEFT EXIT REGION OF THE
UPPER JET...AND WEAK SHORTWAVES. PER THE LATEST MODEL AND MOS
GUIDANCE...DECREASED MAX TEMPS AROUND MARQUETTE/GREEN LAKE AND SAUK
COUNTIES A COUPLE OF DEGREES. OTHERWISE NO OTHER CHANGES FOR THE
TODAY PERIOD.
12Z NAM CAME IN A LITTLE SLOWER WITH THE ONSET OF THE QPF...BUT
BUFKIT SNDGS STILL SHOW FULL COLUMN SATURATION AT MSN AT 06Z. RUC IS
ABOUT AN HOUR LATER WITH THE SATURATION. WILL PROBABLY STICK CLOSE
TO THE PREVIOUS FORECAST...SINCE PRECIP SHOULD BEGIN FALLING RIGHT
WHEN COLUMN SATURATION OCCURS.
&&
.AVIATION/18Z TAFS/...VFR CIGS WILL SLOWLY LOWER AS SOUTH WINDS
SLOWLY INCREASE LOW LEVEL MOISTURE THIS AFTERNOON INTO EARLY THIS
EVENING. SLOWED THE TIMING OF THIS LOWERING TO MID AFTERNOON RATHER
THAN RIGHT AT 18Z. MVFR CIGS WILL DEVELOP FROM WEST TO EAST ACROSS
THE CWA DURING THE AFTERNOON INTO THE EARLY EVENING. RAIN VIA
WARM...MOIST ADVECTION WILL THEN ARRIVE AT THE TAF SITES BY LATE
EVENING AND CONTINUE INTO WED. CIGS WILL FALL TO LIFR WITH THE RAIN
AND SATURATION OF THE LOW LEVEL ATMOSPHERE WHILE VSBYS WILL FALL TO
IFR.
THERE SHOULD BE A PERIOD OF TIME WED MORNING WHERE THERE IS A LULL
IN THE STEADY RAIN...WHICH WOULD ACTUALLY DIMINISH VISIBILITY AND
LOWER THE CEILING HEIGHTS. NOT SURE OF EXACT TIMING OF THIS
LULL...THEN RAIN WILL INCREASE ONCE AGAIN EARLY WED AFTERNOON AS THE
MAIN UPPER AND SFC LOW APPROACH SOUTHERN WI.
&&
.MARINE...INCREASING SOUTHERLY WINDS WILL ALLOW FOR BUILDING WAVES
TO NEAR-SMALL CRAFT ADVISORY CRITERIA WED AFTERNOON. WEST WINDS
BEHIND THE DEPARTING LOW ON THU WILL INCREASE...AND WIND GUSTS TO 25
KNOTS ARE POSSIBLY/LIKELY WITH THE COLD AIR ADVECTION. SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED. NEED TO PIN DOWN EXACT TIMING AFTER
RUNNING THE WAVE MODEL...AND THEN EXPECT A HEADLINE WITH THE
AFTERNOON ISSUANCE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1019 AM MST TUE DEC 13 2011
.DISCUSSION...VISIBILITIES HAVE IMPROVED SOME OVER THE EAST PART OF
THE CWA AS OF 17Z. THAT TREND SHOULD CONTINUE THROUGH THE EARLY
AFTERNOON BEFORE THE FOG DISSIPATES. IN A RECENT UPDATE...HAVE
ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AND HAVE KEPT FOG IN THE
FORECAST FOR AREAS BELOW 4500 FEET MSL THROUGH 20Z.
.AVIATION...18Z TAF ISSUANCE...
IFR CEILINGS AND VISIBILITIES IN FOG WILL PERSIST THROUGH 20Z OVER
THE EAST PART OF THE CWA. RECENT TRENDS HAVE BEEN FOR THE CONDITIONS
TO SLOWLY IMPROVE AS BOUNDARY LAYER WINDS BECOME MORE SOUTHWESTERLY.
VFR CONDITIONS WILL BE OVER THE ENTIRE CWA BY 21Z. OVER MUCH OF
THE PANHANDLE...IFR CEILINGS AND VISIBILITIES IN FOG WILL RETURN
AFTER 04Z AND THEN IMPROVE AFTER 11Z. CLOUD DEPTH WILL AGAIN BE
QUITE SHALLOW TONIGHT AND VISIBILITIES PERHPAS NOT AS LOW TONIGHT
AS THRY WERE RECENTLY. VFR CONDITIONS WILL BE OVER THE ENTIRE CWA
AFTER 15Z. WEST TO NORTHWEST WINDS WILL GUST AS HIGH AS 30 KNOTS
OVER THE CWA AFTER 15Z AND CONTINUE THROUGH WEDNESDAY EVENING.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 901 AM MST TUE DEC 13 2011/...
.DISCUSSION...
FOG PERSISTS AT MID MORNING OVER THE EAST PART OF THE CWA. THE FOG
WAS DENSE IN PLACES OVER THE SOUTHERN PANHANDLE. THE DEPTH OF THE
LOW CLOUDS AND FOG WAS BETWEEN 500 AND 1500 FEET AS OF 15Z. THE
VISIBILITIES HAVE BEEN SLOWLY IMPROVING WITH INCREASED MIXING AND
A MORE SOUTHWEST BOUNDARY LAYER WIND. THE TIMING OF THE DENSE FOG
ADVISORY OF 17Z MAY WORK OUT WELL FOR THE SOUTHERN PANHANDLE. WILL
TAKE A CLOSER LOOK SOON IN REGARDS TO THE TIMING OF THE DISSIPATION
OF THE FOG. IN A RECENT UPDATE...ADJUSTED THE AREAS OF FOG THROUGH
MIDDAY AND ADJUSTED TEMPERATURES DOWN A BIT FOR THE PANHANDLE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 452 AM MST TUE DEC 13 2011/...
.AVIATION...12Z TAF ISSUANCE
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW LOW CLOUDS AND
FOG OVER THE NEBRASKA PANHANDLE AND BEGINNING TO SPREAD WESTWARD
TOWARD KCYS. LIFR AND IFR CONDITIONS SHOULD PERSIST ACROSS THE
SOUTHERN NEBRASKA PANHANDLE TERMINALS THROUGH MID TO LATE MORNING
BASED ON SOUNDINGS AND HRRR OUTPUT. INCLUDED TEMPO IFR VISBYS AND
CIGS FROM 12-14Z AT KCYS. LOW LEVEL DRYING WILL TAKE PLACE DURING
THE AFTERNOON ACROSS THE SOUTHERN PANHANDLE AND THE STRATUS WILL
BEGIN TO BREAK UP AT THAT TIME. WINDS WILL BE LIGHT DURING THE TAF
PERIOD AT ALL TERMINALS.
FINCH
&&
PREV DISCUSSION... /ISSUED 233 AM MST TUE DEC 13 2011/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LOW CLOUDS AND FOG HAS SPREAD OVER MUCH OF THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE THIS MORNING AND SHOULD TRY TO CREEP A BIT MORE
WESTWARD OVER THE NEXT FEW HOURS...ESPECIALLY UP THE NORTH PLATTE
RIVER VALLEY. SOME OF IT DENSE AND HAVE ISSUED A DENSE FOG ADVISORY
FOR THOSE AREAS WHERE IT IS MOST WIDESPREAD. THE FOG SHOULD SLOWLY
DISSIPATE LATER THIS MORNING. OTHERWISE MAINLY DRY WEATHER EXPECTED
ACROSS MOST OF THE CWA THROUGH THURSDAY WITH JUST SOME SNOW SHOWERS
ON OCCASION OVER THE HIGHER SOUTHERN MTNS AS SOME MOISTURE INTERACTS
WITH OROGRAPHICS. UPPER LOW OVER THE FAR SOUTHWEST WILL OPEN AND
MOVE ENE TODAY THROUGH WEDS AND PASS SOUTH OF THE CWA WITH MINIMAL
EFFECTS HERE. NEXT WEAK PUSH OF COOLER AIR SHOULD ARRIVE EARLY WEDS
BUT ONLY ABOUT 5 DEGREES OF COOLING EXPECTED OVERALL. SHORT UPPER
RIDGE WILL TRANSLATE ACROSS THE REGION THURSDAY THEN EFFECTS FROM
SPLITTING UPPER SHORTWAVE OVER THE PACIFIC NORTHWEST COULD SPREAD
SOME LIGHT SNOWS OVER WESTERN PARTS OF THE CWA LATE THURSDAY NIGHT.
LONG TERM...FRIDAY THROUGH WEDNESDAY
WEAK SHORTWAVE MOVES THROUGH THE CWA FRIDAY AFTERNOON. GFS AND
ECMWF NOT FORECASTING MUCH IN THE WAY OF PRECIP WITH THIS
SHORTWAVE...BUT WOULD IMAGINE THAT SOME OROGRAPHIC SNOW SHOWERS
ARE POSSIBLE...SO MAINTAINED THE INHERITED LOW CHANCE POPS OVER
THE MOUNTAINS TO OUR WEST.
TRANQUIL CONDITIONS EXPECTED OVER THE WEEKEND AS HIGH PRESSURE
PREVAILS. LOOKING AT FAIRLY WARM TEMPERATURES SATURDAY AND SUNDAY
AS 700MB TEMPERATURES FORECAST ABOVE FREEZING.
NEXT CHANCE FOR PRECIP LOOKS TO BE SUNDAY NIGHT INTO MONDAY AS A
LOW PRESSURE SYSTEM TRACKS ACROSS COLORADO. GFS AND ECMWF DIFFER
ON SOLUTIONS OF THIS LOW. ECMWF DEVELOPS A SECONDARY UPPER LOW THAT
TRACKS FURTHER NORTH THAN THE GFS. KEPT SLIGHT CHANCE POPS GOING
IN THE FORECAST FOR MONDAY RESPECTING THE ECMWF SOLUTION.
FIRE WEATHER...
FAIRLY LIGHT WINDS FORECAST. FIRE WEATHER CONCERNS WILL BE MINIMAL
OVER THE CWA THROUGH EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR
NORMAL OVERALL AND...OUTSIDE OF WEDNESDAY...WINDS WILL BE FAIRLY
LIGHT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RE
LONG TERM/AVIATION...CLAYCOMB
UPDATE...WEILAND