Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/25/12
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1042 AM MDT TUE OCT 23 2012
.UPDATE...
ISSUED AT 1042 AM MDT TUE OCT 23 2012
PUBLIC REPORT THAT STRONG WINDS ARE BUFFETING VEHICLES NEAR RIDGWAY.
WITH REMOTE MOUNTAIN SITES IN THE NWRN SAN JUANS AND DOUGLAS PASS
INDICATING GUSTY WINDS...WILL EXPAND THE WIND ADVISORY TO INCLUDE
THESE AREAS. THESE REPORTS CONFIRM HRRR MODEL SURFACE WIND GUST
TRENDS THAT SHOW THE UNCOMPAHGRE RIDGE TOP INTO THE NWRN SAN
JUANS BEING THE BULLSEYE FOR STRONGEST WINDS.
UPDATE ISSUED AT 925 AM MDT TUE OCT 23 2012
WINDS CONTINUE TO BE PROBLEMATIC TODAY WITH GUSTS APPROACHING 45
MPH AT SEVERAL LOCATIONS. WITH TIGHT GRADIENT FLOW AND A WELL
MIXED LAYER (AT LEAST UP TO 600 MB FROM THE MORNING SOUNDING)...WINDS
FROM ALOFT WILL TRANSLATE TO THE SURFACE...ESPECIALLY WITH THE
BOUNDARY LAYER NEARLY DRY ADIABATIC. SURFACE WINDS HAVE BEEN
ERRATIC...ESPECIALLY ALONG THE I70 CORRIDOR...BUT LAMP GUIDANCE
SUGGEST THAT WINDS WILL BECOME EVEN MORE ERRATIC. HAVE ELECTED TO
ISSUE ANOTHER WIND ADVISORY FOR THE REMAINDER OF THE DAY. APPEARS
THAT WINDS WILL DECOUPLE FAIRLY QUICKLY THIS EVENING AS SURFACE
FRONT BEGINS TO SEEP INTO THE FORECAST AREA.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 409 AM MDT TUE OCT 23 2012
TODAY: PATTERN SHOWS ONLY SLIGHT CHANGE TODAY AS THE BROAD TROUGH
OVER THE PACIFIC COAST STAYS PUT. AS A RESULT...VIGOROUS SOUTHWEST
FLOW WILL CONTINUE ACROSS THE AREA. HOWEVER...BOTH GFS40 AND NAM12
INDICATED 7H HEIGHT GRADIENT WILL RELAX ACROSS THE AREA RESULTING
IN DECREASED WIND SPEED. CONSEQUENTLY...IT NOW APPEARS UNLIKELY
THAT WIND CRITERIA WILL BE MET THIS AFTERNOON AND THEREFORE
CANCELLED THE WIND ADVISORY FOR THIS AFTERNOON AND EVENING.
THE STATIONARY FRONT JUST NORTH OF THE FORECAST AREA OVER THE PAST
SEVERAL DAYS WILL SAG SOUTHWARD AS LOW PRESSURE MOVES EASTWARD
ACROSS THE NORTHERN PLAINS. THE BOUNDARY WILL COME TO REST NEAR
THE NORTHEAST UTAH/NORTHWEST COLORADO BORDER AREA THIS AFTERNOON.
LOW LEVEL CONVERGENCE ALONG THE BOUNDARY COMBINED WITH CHANNELED
VORTICITY ALOFT SHOULD FOCUS SHOWER ACTIVITY IN THIS AREA. ADDED
SOME ISOLATED THUNDERSTORMS ACROSS THE EXTREME NORTH DURING THE
AFTERNOON AS FORECAST SOUNDINGS INDICATED THE ATMOSPHERE TO BE
CONDITIONALLY UNSTABLE IN THE VICINITY OF THE FRONTAL BOUNDARY.
ADVECTION OF COOLER AIR ACROSS THE NORTHERNMOST ZONES WILL RESULT
IN ABOUT 5 DEGREES OF COOLING TODAY WHILE TEMPERATURES SHOULD BE
LARGELY UNCHANGED SOUTH. FELT MAV MOS WAS A BIT AGGRESSIVE WITH
THE COOLING ACROSS THE NORTH SO HEWED CLOSER TO THE MET GUIDANCE.
TONIGHT-THURSDAY: COMPLICATED PATTERN WILL EVOLVE AS ENERGY
CONTINUES TO EJECT FROM THE PACIFIC LOW PRESSURE SYSTEM
TONIGHT...BEFORE THE MAIN TROUGH SHIFTS EAST OVER THE WESTERN
CONUS WED THROUGH THU.
A SURFACE FRONT WILL GENERALLY REMAIN STALLED ALONG...AND JUST TO
THE NORTH OUR THE CWA BORDER TONIGHT. SO THROUGHOUT THE NIGHT WE
SHOULD CONTINUE TO SEE A FEW SHOWERS OVER NORTHEAST UT AND FAR
NORTHWEST CO ALONG AND JUST TO THE SOUTH OF THIS BAROCLINIC ZONE.
ALSO CANNOT RULE OUT THE POSSIBILITY OF A FEW LIGHTNING STRIKES.
THE GRADIENT WILL REMAIN TIGHT ACROSS THE ENTIRE AREA. SO GUSTY
WINDS WILL CONTINUE OVER EXPOSED HIGHER TERRAIN...BUT ESPECIALLY
ALONG THE CO/WY BORDER. WINDS IN THE VALLEYS SHOULD DIMINISH BY OR
SHORTLY AFTER SUNSET AS THE AIR MASS DECOUPLES. NIGHTTIME
TEMPERATURES WILL REMAIN VERY MILD DUE TO THE UNSETTLED NATURE OF
THE PATTERN.
THE FRONT WILL FINALLY DROP SOUTHWARD AND INTO THE AREA EARLY WED
AS THE MAIN UPPER PATTERN SHIFTS EAST. THE FRONT WILL THEN
PROCEED SOUTHWARD THROUGH THE DAY...REACHING THE I-70 CORRIDOR
EARLY TO MID AFTERNOON AND TO THE SOUTHERN BORDER LATE AFTERNOON
TO EARLY EVENING. WINDS WILL AGAIN MIX INTO THE LOWER ELEVATIONS
EARLY IN THE DAY AHEAD OF THE FRONT...AND DUE TO THE CONTINUED
TIGHT GRADIENT RESULTING FROM THE APPROACHING TROUGH. THE CHANCE
FOR SHOWERS...AND A FEW THUNDERSTORMS...WILL ALSO SPREAD TO THE
SOUTH. HOWEVER MODELS INDICATE THAT MOISTURE WILL BE SOMEWHAT
LIMITED ACROSS OUR CWA AS THIS SYSTEM PASSES...ESPECIALLY OVER THE
SOUTHERN PORTION. THAT SAID...MODELS CONTINUE TO SHOW GOOD UPPER
LEVEL SUPPORT WITH THE NOSE OF THE 120+ JET CORE RAKING THE AREA
THROUGH THE DAY. INSTABILITY ALSO INCREASES AS TEMPS AT 500 MB
DROP FROM AROUND -15C AT GJT WED MORNING TO AROUND -20C IN THE
AFTERNOON. THEN AS THE MAIN TROUGH AXIS PASSES WED NIGHT 500 MB
TEMPS DROP TO -26 AT GJT BY 12Z THU. THEN ON THU...A REINFORCING
COLD SHOT WILL APPROACH FROM THE NORTHWEST TO KEEP THE AIR MASS
UNSETTLED...AND SNOW ONGOING OVER THE NORTHERN AND CENTRAL
MOUNTAINS.
SNOW LEVELS ARE EXPECTED TO FALL AS THE FRONT PASSES ON WED...WITH
SNOW LOWERING INTO THE VALLEYS WED NIGHT. THE NORTH WILL REMAIN
FAVORED...WITH MOUNTAIN SNOW LIKELY WED-THU. AGREE WITH THE
PREVIOUS SHIFT THAT ACCUMULATIONS COULD RANGE FROM 3-6 INCHES
OVER THE NORTHWEST FACING SLOPES OF THE PARK...GORE...FLATTOPS AND
ELKHEAD RANGES.
MUCH COOLER DAYTIME TEMPERATURES EXPECTED ON WED ESPECIALLY OVER
THE NORTH...WITH ANOTHER BIG DROP ON THU. OVERNIGHT LOWS WED
NIGHT WILL ALSO BE UP TO 10 DEGREES COOLER THAN TONIGHT`S VALUES.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 418 AM MDT TUE OCT 23 2012
A TRAILING SHORTWAVE SWEEPS EASTWARD ACROSS THE REGION THURSDAY
NIGHT FINALLY CARRYING THE MAIN TROUGH AXIS EAST OF THE AREA BY
SUNRISE FRIDAY. EXPECT THIS FEATURE WILL SUSTAIN SNOW OVER THE
NORTHERN AND CENTRAL MOUNTAINS OVERNIGHT. AS BEFORE...MOISTURE NOT
LOOKING ALL THAT IMPRESSIVE AND AT THIS POINT IT APPEARS
ADDITIONAL ACCUMULATIONS WILL RANGE FROM 1 TO 3 INCHES. THE SOUTH
REMAINS MOISTURE STARVED SO WILL CONTINUE WITH LOW END POPS OVER
THE SAN JUANS WITH LESS THAN 10 PERCENT POPS ACROSS THE LOWER
ELEVATIONS.
MODELS INDICATED SHOWERS WILL DISSIPATE BY MIDDAY FRIDAY WITH A
RETURN TO DRY WEATHER UNDER NORTHWEST FLOW MOVING INTO THE
WEEKEND. GFS MAINTAINS A FAIRLY VIGOROUS NORTHWEST FLOW WITH A
SERIES OF WEAK DISTURBANCES BRUSHING THE NORTHERN COLORADO
MOUNTAINS BRINGING OCCASIONAL LIGHT SHOWERS SATURDAY THROUGH
MONDAY. IN CONTRAST...BOTH THE ECMWF AND THE GEM MODELS BUILD A
FLAT RIDGE OVER THE REGION AND NO PRECIPITATION. GIVEN MODEL
DIFFERENCES FEEL COMPELLED TO HOLD THE LINE WITH THE BLENDED MODEL
SOLUTION WHICH FEATURED SLIGHT CHANCES OVER THE NORTHERN MOUNTAINS
INTO EARLY NEXT WEEK.
THE INFLUX OF COLDER AIR BEHIND THE FRONT WILL BRING SOME OF THE
COLDEST TEMPERATURES EXPERIENCED SO FAR THIS FALL WITH HIGHS
RUNNING ABOUT 15 DEGREES BELOW NORMAL FRIDAY. OVERNIGHT LOWS
SATURDAY MORNING THREATEN TO BRING SEASON ENDING FREEZING
TEMPERATURES TO SOUTHEAST UTAH...THE GRAND VALLEY...AND THE LOWER
ELEVATIONS OF MONTEZUMA AND DOLORES COUNTIES IN SOUTHWEST
COLORADO. A WARMING TREND BEGINS SATURDAY AND WILL CONTINUE INTO
EARLY NEXT WEEK WITH HIGHS RETURNING TO NEAR NORMAL LEVELS BY
MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1042 AM MDT TUE OCT 23 2012
MECHANICAL TURBULENCE AND LOW LEVEL WIND SHEAR WILL BE THE MAIN
AVIATION HAZARD TODAY. SOUTHWEST WIND WITH GUSTS IN THE 25-35KT
RANGE WILL BE COMMON. SURFACE WINDS ARE EXPECTED TO DIMINISH AFTER
01Z THIS EVENING AS COLD FRONT SEEPS INTO NORTHEAST UTAH AND
NORTHWEST COLORADO.
ISOLATED SHOWERS NEAR THE WYOMING BORDER WILL PARTIALLY OBSCURE
MOUNTAIN TOPS. ISOLATED THUNDERSTORMS MAY OCCUR AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WIND ADVISORY UNTIL 7 PM MDT THIS EVENING FOR COZ001>003-007-008-
017-018.
UT...NONE.
&&
$$
UPDATE...PF
SHORT TERM...NL/EH
LONG TERM...NL
AVIATION...PF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
928 AM MDT TUE OCT 23 2012
.UPDATE...A WEAK DISTURBANCE HAS CREATED SOME ISOLATED SNOW
SHOWERS OVER THE MOUNTAINS NEAR SUMMIT COUNTY THIS MORNING. HAVE
UPDATED THE GRIDS TO ADD MENTION OF THESE. ATMOSPHERE SEEMS TO BE
MIXING QUITE WELL ALREADY THIS MORNING AS WINDS ARE BECOMING GUSTY
OUT OF THE SOUTHWEST ALREADY OVER THE PALMER DIVIDE AND INTO THE
URBAN CORRIDOR.
&&
.AVIATION...WINDS WILL CONTINUE TO BE THE PROBLEM OF THE DAY
TODAY. STRONGER SOUTHWEST WINDS OVER THE PALMER DIVIDE ARE
OCCURRING AS THE BOUNDARY LAYER IS MIXING SOONER THAN FORECAST.
THESE ARE SPREADING INTO THE AREA AIRPORTS ALTHOUGH THERE IS A
NORTHWEST DIRECTION COMING OUT OF LARIMER...BOULDER AND WELD
COUNTIES. BELIEVE THE SOUTHWEST SHOULD BECOME PREVAILING SOON.
ADDED GUSTS INTO THE TAFS AS WELL. BOTH THE NAM AND THE GFS
CONTINUE TO SHOW A SWITCH TO WK NNELY FOR A FEW HOURS AROUND 00Z BEFORE
BECOMING MORE SSW AFTER 03Z. THIS COULD BE AN INITIAL SURGE AS THE
HRRR AND RUC ARE PICKING UP ON IT AS WELL. HOWEVER THE MAIN COLD
FRONT IS STILL EXPECTED TO MOVE INTO THE AREA BY 12Z WITH WINDS
BECOMING MORE NLY. LATEST SOUNDINGS SHOW SOME POTENTIAL FOR
3000-4000 FT BKN CEILINGS WED MORNING BETWEEN 12Z AND 16Z.
&&
.PREV DISCUSSION... /ISSUED 311 AM MDT TUE OCT 23 2012/
SHORT TERM...LOW CLOUDS AND FOG HAVE DEVELOPED OVER FAR NERN CO
EARLY THIS MORNING BUT SHOULD GRADUALLY BURN OFF AFTER 15Z. MEANWHILE
RATHER STG SWLY FLOW ALOFT WILL BE OVER THE AREA THRU TONIGHT AS
AN UPPER LEVEL LOW REMAINS OVER THE PACIFIC NW. SOME MOISTURE IS
EMBEDDED IN THIS FLOW AND WILL AFFECT MAINLY WRN AREAS OF JACKSON
COUNTY. THERE ARE SIGNIFICANT DIFFERENCES BETWEEN THE NAM AND GFS
WITH RESPECT TO PCPN CHANCES OVER ZN 31 TODAY AND TONIGHT AS THE
NAM IS DRIER WHILE THE GFS IS MUCH MORE WET. BASED ON POSITION OF
UPPER LEVEL JET APPEARS BEST CHC OF PCPN WOULD STAY NW OF ZN 31
HOWEVER WILL KEEP IN CHC POPS TODAY AND TONIGHT. ELSEWHERE WILL
KEEP FCST DRY. AS FAR AS HIGHS 850-700 MB TEMPS ARE SIMILAR TO SUN
HOWEVER LOW LEVEL FLOW EAST OF THE MTNS WILL BE MORE SWLY THIS
AFTN. THUS WOULD THINK HIGHS WOULD RISE INTO THE LOWER TO MID 70S
ACROSS MOST OF NERN CO. MEANWHILE AFTN HUMIDITY LEVELS OVER THE
PALMER DIVIDE DROP DOWN TO AROUND 15 PERCENT AND COMBINED WITH
GUSTY WSW WINDS COULD SEE RED FLAG CONDITIONS FOR A FEW HOURS IN
ZNS 46 AND 47.
FOR TONIGHT WILL CONTINUE TO SEE A CHC OF SHOWERS OVER ZN 31 BUT
WILL KEEP REST OF THE AREA DRY. A CDFNT WILL MOVE INTO NERN CO
AFTER MIDNIGHT WITH SOME POTENTIAL FOR LOW CLOUDS TO DVLP TOWARDS SUNRISE.
LONG TERM...OVERALL NO BIG CHANGES IN THE FORECAST WITH THE MAIN
AREA OF CONCERN IN THE WEDNESDAY TO FRIDAY WINDOW. THE MDLS HAVE A
STRONG SOUTHWESTERLY FLOW ALOFT OVER COLORADO ON WEDNESDAY WITH A
130KT UPPER LEVEL JET OVER WESTERN AND NORTHERN COLORADO AT 00Z
THURSDAY. THE NAM/GFS MDLS INDICATE WEAK TO MODERATE QG ASCENT
OVER THE CWFA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. SEE NO
REASON TO ARGUE WITH THE LIKELY POPS IN THE GRIDS AT THIS TIME FOR
THE HIGH COUNTRY. SPATIAL CROSS-SECTIONS INDICATE THE AMS
SATURATING WEDNESDAY EVENING WITH UPSLOPE DEVELOPING TO AROUND 750
MB OVERNIGHT WITH A MOIST SWLY FLOW ALOFT OVERRUNNING THE AIRMASS.
NAM12 SPATIAL CROSS-SECTIONS ALSO INDICATE THE POTENTIAL FOR
BANDING ASSOCIATED WITH CONVECTIVE SYMMETRIC INSTABILITY OR C.S.I.
AREA THE THE GREATEST POTENTIAL FOR ACCUMULATING SNOWFALL WILL BE
NORTH OF INTERSTATE 70...ON THE COLDER SIDE OF THE UPPER JET SO
ZONES 31...33 AND 35 SHOULD DO THE BEST. BUT WITH BANDED BANDS
ZONES 30..32 AND 38 MAY ALSO SEE SOME DECENT SNOWFALL. WL ALSO
MENTION A SLIGHT CHANCE OF TSTMS WEDNESDAY AFTN/EVENING AS WELL.
WILL KEEP THE HIGHEST POPS/ACCUMULATION IN THESE AREA. ALTHOUGH
THE AMS WILL REMAIN SATURATED THURSDAY MORNING... INCREASING MID
LEVEL SUBSIDENCE SHOULD ALLOW FOR LIGHT SNOWFALL TO TAPER OFF BY
18Z THURSDAY. A SHORT WAVE RIDGE WILL BE OVER COLORADO BY THURSDAY
AFTN AHEAD OF ANOTHER WEAK SHORT WAVE DROPPING OUT OF THE NORTHERN
ROCKIES. THIS NEXT SYSTEM WILL DROP ACROSS NORTHERN COLORADO
AROUND 06Z FRIDAY BRINGING WITH IT ANOTHER SURGE OF COLD AIR ALONG
WITH ANOTHER CHANCE FOR SNOW. THIS SYSTEM MORE PROGRESSIVE AND
WITH NO UPSLOPE ASSOCIATED WITH IT AS THE SHORT WAVE BRUSHES
ACROSS THE CWFA. AS A RESULT...THE BEST CHC FOR PCPN MAY BE IN BE
IN THE NORTHERN MOUNTAINS AND FAR NORTHEAST PLAINS. IT IS STILL
PROGGED TO BE DRIER OVER THE WEEKEND. A STRONG NORTHWESTERLY FLOW
ALOFT WILL BE OVER THE STATE WITH JUST ENOUGH MOISTURE FOR A
SLIGHT CHANCE OF SNOW IN THE MOUNTAINS. TEMPERATURES WILL MODIFY
SOME BUT THEY WILL BE BELOW NORMAL THROUGH SATURDAY THROUGH
MONDAY.
AVIATION...WINDS EARLY THIS MORNING HAVE BEEN LIGHT SLY AND THE
HRRR KEEPS THEM THAT WAY THRU 18Z. BY EARLY AFTN THEY MAY BECOME
MORE SWLY AS MIXING OF THE BNDRY LAYER OCCURS. BY 00Z THE NAM
CONTINUES TO SHOW A SWITCH TO WK NNELY FOR A FEW HOURS BEFORE
BECOMING MORE SSW AFTER 03Z. OVERNIGHT A CDFNT WILL MOVE INTO THE
AREA BY 12Z WITH WINDS BECOMING MORE NLY. LATEST SOUNDINGS SHOW
SOME POTENTIAL FOR 3000-4000 FT BKN CEILINGS WED MORNING BETWEEN
12Z AND 16Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM MDT THIS EVENING FOR
COZ246-247.
&&
$$
SHORT TERM...RPK
LONG TERM....COOPER
UPDATE/AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS ALBANY NY
735 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TODAY AND
TONIGHT...AS A WEAK WAVE OF LOW PRESSURE TRAVELS ALONG IT. THIS WILL
BRING CLOUDS AND SOME RAIN TO THE REGION THROUGH WEDNESDAY
MORNING...WITH THE BEST CHANCE OF RAIN EXPECTED FROM THE GREATER
CAPITAL REGION AND AREAS SOUTH AND WEST. TEMPERATURES WILL REMAIN
SOMEWHAT COOL DUE TO CLOUDS AND RAIN THROUGH WEDNESDAY...BEFORE
GRADUALLY WARMING FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM EDT...HIGH CLOUDS ARE GRADUALLY INCREASING ACROSS THE
REGION...WITH MID LEVEL CLOUDS SLOWLY APPROACHING FROM THE WEST.
TEMPS HAVE DROPPED INTO THE UPPER 30S TO LOWER 40S IN MOST
VALLEYS...WITH MID 30S ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS.
CLOUDS WILL CONTINUE TO INCREASE/THICKEN FROM W TO E THROUGH MID
MORNING. SOME SUNSHINE MAY BE DIMLY VISIBLE AT TIMES UNTIL
THEN...ESP FOR AREAS E OF THE HUDSON RIVER VALLEY...AND INTO
SOUTHERN VT.
AS ONE SHORTWAVE...CURRENTLY OVER LOWER MICHIGAN...TRANSLATES
EASTWARD TODAY...INCREASING ISENTROPIC LIFT TO THE EAST OF THIS
FEATURE SHOULD ALLOW RAIN TO EXPAND INTO WESTERN AND SOUTHERN
PORTIONS OF THE REGION BY MID TO LATE MORNING. 00Z/23 MODELS AND
03Z/SREFS HAVE TRENDED FURTHER NORTH WITH THE EXPECTED RAIN SHIELD
WITH THIS SYSTEM...AND THIS IS FURTHER SUPPORTED BY RECENT
UPSTREAM RADAR TRENDS...AS WELL AS THE LATEST HRRR MODEL.
THEREFORE...HAVE RAISED POPS INTO THE LIKELY RANGE FOR CENTRAL AND
SOUTHERN PORTIONS OF THE REGION...FOR THIS
AFTERNOON/EVENING...WITH THE NORTHERN EDGE OF LIKELY POPS JUST N
OF SARATOGA...AND INTO EXTREME SW VT. IT IS POSSIBLE THAT THIS
INITIAL SURGE OF RAINFALL WEAKENS A BIT UPON MOVING FURTHER E INTO
OUR REGION...AS IT OUTRUNS THE BEST LOW LEVEL MOISTURE TRANSPORT
CURRENTLY FEEDING INTO IT FROM THE OHIO VALLEY REGION.
HOWEVER...RENEWED SHOWERS/RAIN WILL LIKELY DEVELOP ON THE
NORTHERN PERIPHERY OF THE SHORTWAVE AS IT TRANSLATES NEAR OR JUST
S/W OF THE CAPITAL REGION LATER THIS AFTERNOON OR EARLY THIS
EVENING.
RAINFALL AMTS SHOULD BE GENERALLY LIGHT TO MODERATE...WITH AN AREA
OF ONE QUARTER...TO ONE HALF INCH EXPECTED JUST S/W OF THE CAPITAL
REGION...ACROSS THE SCHOHARIE VALLEY AND CATSKILLS. SOMEWHAT
HIGHER AMTS ARE POSSIBLE WITHIN ANY EMBEDDED BANDS THAT
DEVELOP...AS MID LEVEL FRONTOGENETICAL FORCING INCREASES LATER
THIS AFTERNOON. THEREFORE...HAVE INCLUDED A SMALLER AREA WITHIN
THE MORE GENERAL 0.25-0.50 REGION OF 0.50-0.75.
SOME WEAK ELEVATED INSTABILITY WILL PASS ACROSS SOUTHERN AREAS
LATER THIS AFTERNOON...WHICH COULD SUPPORT A FEW RUMBLES OF
THUNDER. HOWEVER...OVERALL ELEVATED INSTABILITY LOOKS MUCH WEAKER
THAN WHAT OCCURRED UPSTREAM DURING THE OVERNIGHT HOURS WHERE SOME
CG LIGHTNING STRIKES WERE NOTED. SO...HAVE KEPT OUT MENTION OF
THUNDER AT THIS TIME.
FOR TEMPS...GIVEN THE EXPECTED INCREASE IN CLOUD COVER AND
EVENTUAL RAIN...HAVE SIDED CLOSER TO THE COOLER MET MOS IN MOST
AREAS...WITH MID TO UPPER 50S EXPECTED FOR MAX TEMPS. GIVEN
INITIAL DEWPOINTS IN THE LOWER 40S...WET BULB COOLING MAY ACTUALLY
ALLOW TEMPS TO FALL ONCE THE RAIN DEVELOPS LATER THIS MORNING INTO
THE AFTERNOON. SHOULD THE RAIN DEVELOP ANY SOONER...EVEN COOLER
MAX TEMPS WOULD BE POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...THE FIRST SHORTWAVE SHOULD TRANSLATE E/SE ACROSS THE
SOUTHERN HALF OF THE REGION THIS EVENING. THEN...A SECOND
SHORTWAVE SHOULD APPROACH SOUTHERN AREAS CLOSER TO DAYBREAK. THIS
SHOULD FAVOR SOUTHERN AREAS FOR THE BEST CHC FOR RAIN
OVERNIGHT...AFTER THE INITIAL SURGE OF LIGHT TO MODERATE RAINFALL
THIS EVENING. THEREFORE...WILL TREND LIKELY POPS SOUTHWARD THROUGH THE
EVENING AND OVERNIGHT HOURS. NORTHERN AREAS MAY ACTUALLY HAVE SOME
THIN SPOTS IN THE CLOUDS DEVELOP AT TIMES OVERNIGHT...WHICH COULD
ALLOW FOR COOLER TEMPS...AND SOME PATCHY FOG. HAVE GENERALLY SIDED
WITH A MAV/MET MOS BLEND...WHICH WERE FAIRLY CLOSE IN MOST AREAS.
WED-WED NT...MAIN FORCING MECHANISMS FOR LIFT SHOULD MOVE S AND E
OF REGION WED MORNING. IN THEIR WAKE...VERY LITTLE IN THE WAY OF
DYNAMICS WILL REMAIN. HOWEVER...LOW LEVEL MOISTURE AND WEAK LOW
LEVEL ISENTROPIC LIFT SHOULD PERSIST...AND MAY ACTUALLY INTENSIFY
WED NT. THEREFORE...WILL KEEP SOME SLIGHT CHC POPS FOR WED
AFTERNOON ACROSS SOUTHERN AREAS...THEN EXPAND POPS NORTHWARD...AND
INCLUDE CHC POPS ACROSS THE EASTERN CATSKILLS. THIS WILL BE FOR
LIGHT RAIN SHOWERS AND AREAS OF DRIZZLE IN THE PERSISTENT LOW
LEVEL ISENTROPIC LIFT...AND WELL AS FOR THE INTERACTION OF THE
HIGHER TERRAIN WITH THE MOIST AND LIGHT SE FLOW. FOR TEMPS...SIDED
CLOSER TO THE COOLER MET MOS AGAIN FOR WED...WITH MAINLY 55-60
EXPECTED IN MOST AREAS DUE TO CLOUDS AND SOME LIGHT RAIN/DRIZZLE.
FOR WED NT...SIDED CLOSER TO THE WARMER MET MOS...DUE TO EXPECTED
CLOUD COVER...WITH WIDESPREAD 40S TO LOWER 50S.
THU-THU NT...DESPITE STRONGLY RISING MID AND UPPER TROPOSPHERIC
HEIGHTS...A PERSISTENT MOIST SE FLOW MAY ACT TO KEEP LOW CLOUDS
AND SOME SPOTTY DRIZZLE FAIRLY PERSISTENT THROUGH THIS PERIOD. HAVE
THEREFORE SIDED CLOSER TO THE COOLER MET MOS...WITH GENERALLY
60-65 EXPECTED FOR MAXES...AND 40S TO LOWER 50S FOR MINS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
NOT A WHOLE LOT OF CHANGE TO THE LONG RANGE FORECAST WITH LOTS OF
SPREAD IN THE GUIDANCE AS TO HOW A POTENTIAL STORM ALONG THE EAST
COAST OF THE U.S EVOLVES. THE FIRST PART OF THE LONG RANGE
FORECAST...FRIDAY AND SATURDAY...LOOKS QUIET...WITH DRY WEATHER...
INCREASING CLOUD COVER AND HIGH TEMPERATURES IN THE 60S TO AROUND
70.
THERE COULD BE SOME ISOLATED SHOWERS ADVANCING INTO WESTERN
AREAS SATURDAY AFTERNOON DEPENDING ON THE TIMING OF THE APPROACH OF
A STRONG NORTHERN STREAM SYSTEM FROM THE MIDWEST AND GREAT LAKES.
THIS NORTHERN STREAM SYSTEM...COMBINED WITH HIGH AMPLITUDE UPPER
RIDGING JUST OFF THE CANADIAN COAST...IS PREDICTED TO INFLUENCE THE
MOVEMENT OF THE TROPICAL SYSTEM CURRENTLY DEVELOPING IN THE
CARIBBEAN.
DECENT CONSENSUS THAT THESE UPPER FEATURES WILL INTERACT WITH THE
TROPICAL SYSTEM...SUPPORTING NORTHWARD MOVEMENT. HOWEVER...THE EXACT
POSITION OF THESE STEERING FEATURES WILL DETERMINE WHETHER THE STORM
IMPACTS THE EASTERN U.S. OR STAYS MAINLY OUT TO SEA. SO...THE RANGE
OF POSSIBLE IMPACTS IS STILL ANYWHERE FROM NO IMPACT TO A
SIGNIFICANT IMPACT...BUT AN EXTREMELY UNUSUAL UPPER PATTERN
CONFIGURATION AND STORM TRACK WOULD BE REQUIRED FOR THE WORST CASE
SCENARIO OF HEAVY RAIN AND WINDS IN EASTERN AND NORTHERN NY AND
WESTERN NEW ENGLAND. STILL AT THE WAIT AND SEE STAGE FOR THIS
POTENTIAL SYSTEM...WHICH AGAIN COULD HAVE MINIMAL IMPACT OR
SIGNIFICANT IMPACT OR SOMETHING IN BETWEEN.
EVEN THE GUIDANCE THAT KEEPS THE STORM WELL OFFSHORE SHOWS OUR
REGION IN THE RIGHT ENTRANCE REGION OF A STRONG UPPER JET SEGMENT
AND DECENT BOUNDARY LAYER THERMAL GRADIENT ALONG A COLD FRONT...
ASSOCIATED WITH THE ADVANCING NORTHERN STREAM SYSTEM THAT COULD BE
GOING NEGATIVE TILT AND TRENDING TOWARD BECOMING A CUT OFF UPPER
LOW. SO EVEN IF WE DO NOT SEE A DIRECT IMPACT FROM THE STORM...SOME
ENHANCED RAINFALL ALONG THE COLD FRONT...AND WITHIN THE REGION OF
STRONG UPPER DYNAMICS...COULD OCCUR SATURDAY NIGHT THROUGH MONDAY.
JUST INDICATING CLOUDY WITH CHANCES OF RAIN SATURDAY NIGHT THROUGH
MONDAY WITH HIGHS IN THE MID 50S TO LOWER 60S SUNDAY AND UPPER 40S
TO MID 50S MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SOME HIGH THIN CLOUDS ARE SPREADING ACROSS THE REGION AHEAD OF AN
UPPER LEVEL SYSTEM IN THE GREAT LAKES AND VFR CONDITIONS SHOULD
PREVAIL THROUGH MUCH OF THIS MORNING. THE SYSTEM IN THE GREAT LAKES
SHOULD TRACK ACROSS OUR REGION THROUGH THE DAY AND EVENING. AN AREA
OF LIGHT RAIN CURRENTLY IN WESTERN NY IS TRACKING TOWARD EASTERN
NY. A FEW SHOWERS COULD BEGIN TO AFFECT TAF SITES BETWEEN 15Z-
17Z. ONCE THE RAIN STARTS AND BECOMES STEADY...IT SHOULD LAST
UNTIL AROUND 00Z-01Z. THE NORTHERN PERIPHERY OF THE STEADIER RAIN
SHOULD BE ABOUT KALB AND KPSF. HOWEVER...PUTTING VCSH IN KGFL.
SOME TEMPO MVFR CEILINGS AND VISIBILITIES ARE POSSIBLE DURING THE
RAIN AT KALB...KPSF AND POU THIS AFTERNOON AND EARLY EVENING. THE
EXACT END OF THE RAIN IS UNKNOWN BUT KEPT VCSH THROUGH 12Z AND
SOME MVFR CEILINGS AT ALL SITES UNTIL THE EXACT TIMING OF THE EXIT
OF THE RAIN IS KNOWN.
WINDS SHOULD BE LIGHT EAST TO NORTHEAST AT 5 KT OR LESS TROUGH THE
TAF PERIOD ENDING AT 06Z TOMORROW.
OUTLOOK...
WED...VFR/MVFR. CHC -SHRA ESPECIALLY SOUTH OF KALB.
THU-FRI...VFR. NO SIG WX.
SAT...VFR. SLGT CHC -SHRA.
&&
.FIRE WEATHER...
FIRE WEATHER RELATED CONCERNS SHOULD REMAIN MINIMAL OVER THE NEXT
3 DAYS DUE TO LIGHT WINDS AND PERSISTENT HIGH RELATIVE
HUMIDITIES. REFER TO LATEST FWFALY FOR MORE SPECIFIC DETAILS.
&&
.HYDROLOGY...
RAINFALL AMTS SHOULD GENERALLY BE ONE QUARTER...TO ONE HALF OF AN
INCH FOR AREAS NEAR AND TO THE SOUTH/WEST OF THE GREATER CAPITAL
REGION THROUGH THURSDAY...WITH LESS THAN ONE QUARTER OF AN INCH
TO THE NORTH AND EAST. SOME MINOR...WITHIN BANK RISES ARE POSSIBLE
FOR AREAS WHERE RAINFALL AMTS REACH ONE HALF INCH OR
GREATER...SUCH AS ON THE ESOPUS...RONDOUT AND SCHOHARIE CREEKS.
GENERALLY DRY CONDITIONS ARE EXPECTED FOR LATE THURSDAY THROUGH
AT LEAST EARLY SATURDAY.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
FIRE WEATHER...KL
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS ALBANY NY
644 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TODAY AND
TONIGHT...AS A WEAK WAVE OF LOW PRESSURE TRAVELS ALONG IT. THIS WILL
BRING CLOUDS AND SOME RAIN TO THE REGION THROUGH WEDNESDAY
MORNING...WITH THE BEST CHANCE OF RAIN EXPECTED FROM THE GREATER
CAPITAL REGION AND AREAS SOUTH AND WEST. TEMPERATURES WILL REMAIN
SOMEWHAT COOL DUE TO CLOUDS AND RAIN THROUGH WEDNESDAY...BEFORE
GRADUALLY WARMING FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM EDT...HIGH CLOUDS ARE GRADUALLY INCREASING ACROSS THE
REGION...WITH MID LEVEL CLOUDS SLOWLY APPROACHING FROM THE WEST.
TEMPS HAVE DROPPED INTO THE UPPER 30S TO LOWER 40S IN MOST
VALLEYS...WITH MID 30S ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS.
CLOUDS WILL CONTINUE TO INCREASE/THICKEN FROM W TO E THROUGH MID
MORNING. SOME SUNSHINE MAY BE DIMLY VISIBLE AT TIMES UNTIL
THEN...ESP FOR AREAS E OF THE HUDSON RIVER VALLEY...AND INTO
SOUTHERN VT.
AS ONE SHORTWAVE...CURRENTLY OVER LOWER MICHIGAN...TRANSLATES
EASTWARD TODAY...INCREASING ISENTROPIC LIFT TO THE EAST OF THIS
FEATURE SHOULD ALLOW RAIN TO EXPAND INTO WESTERN AND SOUTHERN
PORTIONS OF THE REGION BY MID TO LATE MORNING. 00Z/23 MODELS AND
03Z/SREFS HAVE TRENDED FURTHER NORTH WITH THE EXPECTED RAIN SHIELD
WITH THIS SYSTEM...AND THIS IS FURTHER SUPPORTED BY RECENT
UPSTREAM RADAR TRENDS...AS WELL AS THE LATEST HRRR MODEL.
THEREFORE...HAVE RAISED POPS INTO THE LIKELY RANGE FOR CENTRAL AND
SOUTHERN PORTIONS OF THE REGION...FOR THIS
AFTERNOON/EVENING...WITH THE NORTHERN EDGE OF LIKELY POPS JUST N
OF SARATOGA...AND INTO EXTREME SW VT. IT IS POSSIBLE THAT THIS
INITIAL SURGE OF RAINFALL WEAKENS A BIT UPON MOVING FURTHER E INTO
OUR REGION...AS IT OUTRUNS THE BEST LOW LEVEL MOISTURE TRANSPORT
CURRENTLY FEEDING INTO IT FROM THE OHIO VALLEY REGION.
HOWEVER...RENEWED SHOWERS/RAIN WILL LIKELY DEVELOP ON THE
NORTHERN PERIPHERY OF THE SHORTWAVE AS IT TRANSLATES NEAR OR JUST
S/W OF THE CAPITAL REGION LATER THIS AFTERNOON OR EARLY THIS
EVENING.
RAINFALL AMTS SHOULD BE GENERALLY LIGHT TO MODERATE...WITH AN AREA
OF ONE QUARTER...TO ONE HALF INCH EXPECTED JUST S/W OF THE CAPITAL
REGION...ACROSS THE SCHOHARIE VALLEY AND CATSKILLS. SOMEWHAT
HIGHER AMTS ARE POSSIBLE WITHIN ANY EMBEDDED BANDS THAT
DEVELOP...AS MID LEVEL FRONTOGENETICAL FORCING INCREASES LATER
THIS AFTERNOON. THEREFORE...HAVE INCLUDED A SMALLER AREA WITHIN
THE MORE GENERAL 0.25-0.50 REGION OF 0.50-0.75.
SOME WEAK ELEVATED INSTABILITY WILL PASS ACROSS SOUTHERN AREAS
LATER THIS AFTERNOON...WHICH COULD SUPPORT A FEW RUMBLES OF
THUNDER. HOWEVER...OVERALL ELEVATED INSTABILITY LOOKS MUCH WEAKER
THAN WHAT OCCURRED UPSTREAM DURING THE OVERNIGHT HOURS WHERE SOME
CG LIGHTNING STRIKES WERE NOTED. SO...HAVE KEPT OUT MENTION OF
THUNDER AT THIS TIME.
FOR TEMPS...GIVEN THE EXPECTED INCREASE IN CLOUD COVER AND
EVENTUAL RAIN...HAVE SIDED CLOSER TO THE COOLER MET MOS IN MOST
AREAS...WITH MID TO UPPER 50S EXPECTED FOR MAX TEMPS. GIVEN
INITIAL DEWPOINTS IN THE LOWER 40S...WET BULB COOLING MAY ACTUALLY
ALLOW TEMPS TO FALL ONCE THE RAIN DEVELOPS LATER THIS MORNING INTO
THE AFTERNOON. SHOULD THE RAIN DEVELOP ANY SOONER...EVEN COOLER
MAX TEMPS WOULD BE POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...THE FIRST SHORTWAVE SHOULD TRANSLATE E/SE ACROSS THE
SOUTHERN HALF OF THE REGION THIS EVENING. THEN...A SECOND
SHORTWAVE SHOULD APPROACH SOUTHERN AREAS CLOSER TO DAYBREAK. THIS
SHOULD FAVOR SOUTHERN AREAS FOR THE BEST CHC FOR RAIN
OVERNIGHT...AFTER THE INITIAL SURGE OF LIGHT TO MODERATE RAINFALL
THIS EVENING. THEREFORE...WILL TREND LIKELY POPS SOUTHWARD THROUGH THE
EVENING AND OVERNIGHT HOURS. NORTHERN AREAS MAY ACTUALLY HAVE SOME
THIN SPOTS IN THE CLOUDS DEVELOP AT TIMES OVERNIGHT...WHICH COULD
ALLOW FOR COOLER TEMPS...AND SOME PATCHY FOG. HAVE GENERALLY SIDED
WITH A MAV/MET MOS BLEND...WHICH WERE FAIRLY CLOSE IN MOST AREAS.
WED-WED NT...MAIN FORCING MECHANISMS FOR LIFT SHOULD MOVE S AND E
OF REGION WED MORNING. IN THEIR WAKE...VERY LITTLE IN THE WAY OF
DYNAMICS WILL REMAIN. HOWEVER...LOW LEVEL MOISTURE AND WEAK LOW
LEVEL ISENTROPIC LIFT SHOULD PERSIST...AND MAY ACTUALLY INTENSIFY
WED NT. THEREFORE...WILL KEEP SOME SLIGHT CHC POPS FOR WED
AFTERNOON ACROSS SOUTHERN AREAS...THEN EXPAND POPS NORTHWARD...AND
INCLUDE CHC POPS ACROSS THE EASTERN CATSKILLS. THIS WILL BE FOR
LIGHT RAIN SHOWERS AND AREAS OF DRIZZLE IN THE PERSISTENT LOW
LEVEL ISENTROPIC LIFT...AND WELL AS FOR THE INTERACTION OF THE
HIGHER TERRAIN WITH THE MOIST AND LIGHT SE FLOW. FOR TEMPS...SIDED
CLOSER TO THE COOLER MET MOS AGAIN FOR WED...WITH MAINLY 55-60
EXPECTED IN MOST AREAS DUE TO CLOUDS AND SOME LIGHT RAIN/DRIZZLE.
FOR WED NT...SIDED CLOSER TO THE WARMER MET MOS...DUE TO EXPECTED
CLOUD COVER...WITH WIDESPREAD 40S TO LOWER 50S.
THU-THU NT...DESPITE STRONGLY RISING MID AND UPPER TROPOSPHERIC
HEIGHTS...A PERSISTENT MOIST SE FLOW MAY ACT TO KEEP LOW CLOUDS
AND SOME SPOTTY DRIZZLE FAIRLY PERSISTENT THROUGH THIS PERIOD. HAVE
THEREFORE SIDED CLOSER TO THE COOLER MET MOS...WITH GENERALLY
60-65 EXPECTED FOR MAXES...AND 40S TO LOWER 50S FOR MINS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
NOT A WHOLE LOT OF CHANGE TO THE LONG RANGE FORECAST WITH LOTS OF
SPREAD IN THE GUIDANCE AS TO HOW A POTENTIAL STORM ALONG THE EAST
COAST OF THE U.S EVOLVES. THE FIRST PART OF THE LONG RANGE
FORECAST...FRIDAY AND SATURDAY...LOOKS QUIET...WITH DRY WEATHER...
INCREASING CLOUD COVER AND HIGH TEMPERATURES IN THE 60S TO AROUND
70.
THERE COULD BE SOME ISOLATED SHOWERS ADVANCING INTO WESTERN
AREAS SATURDAY AFTERNOON DEPENDING ON THE TIMING OF THE APPROACH OF
A STRONG NORTHERN STREAM SYSTEM FROM THE MIDWEST AND GREAT LAKES.
THIS NORTHERN STREAM SYSTEM...COMBINED WITH HIGH AMPLITUDE UPPER
RIDGING JUST OFF THE CANADIAN COAST...IS PREDICTED TO INFLUENCE THE
MOVEMENT OF THE TROPICAL SYSTEM CURRENTLY DEVELOPING IN THE
CARIBBEAN.
DECENT CONSENSUS THAT THESE UPPER FEATURES WILL INTERACT WITH THE
TROPICAL SYSTEM...SUPPORTING NORTHWARD MOVEMENT. HOWEVER...THE EXACT
POSITION OF THESE STEERING FEATURES WILL DETERMINE WHETHER THE STORM
IMPACTS THE EASTERN U.S. OR STAYS MAINLY OUT TO SEA. SO...THE RANGE
OF POSSIBLE IMPACTS IS STILL ANYWHERE FROM NO IMPACT TO A
SIGNIFICANT IMPACT...BUT AN EXTREMELY UNUSUAL UPPER PATTERN
CONFIGURATION AND STORM TRACK WOULD BE REQUIRED FOR THE WORST CASE
SCENARIO OF HEAVY RAIN AND WINDS IN EASTERN AND NORTHERN NY AND
WESTERN NEW ENGLAND. STILL AT THE WAIT AND SEE STAGE FOR THIS
POTENTIAL SYSTEM...WHICH AGAIN COULD HAVE MINIMAL IMPACT OR
SIGNIFICANT IMPACT OR SOMETHING IN BETWEEN.
EVEN THE GUIDANCE THAT KEEPS THE STORM WELL OFFSHORE SHOWS OUR
REGION IN THE RIGHT ENTRANCE REGION OF A STRONG UPPER JET SEGMENT
AND DECENT BOUNDARY LAYER THERMAL GRADIENT ALONG A COLD FRONT...
ASSOCIATED WITH THE ADVANCING NORTHERN STREAM SYSTEM THAT COULD BE
GOING NEGATIVE TILT AND TRENDING TOWARD BECOMING A CUT OFF UPPER
LOW. SO EVEN IF WE DO NOT SEE A DIRECT IMPACT FROM THE STORM...SOME
ENHANCED RAINFALL ALONG THE COLD FRONT...AND WITHIN THE REGION OF
STRONG UPPER DYNAMICS...COULD OCCUR SATURDAY NIGHT THROUGH MONDAY.
JUST INDICATING CLOUDY WITH CHANCES OF RAIN SATURDAY NIGHT THROUGH
MONDAY WITH HIGHS IN THE MID 50S TO LOWER 60S SUNDAY AND UPPER 40S
TO MID 50S MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SOME HIGH THIN CLOUDS ARE SPREADING ACROSS THE REGION AHEAD OF AN
UPPER LEVEL SYSTEM IN THE GREAT LAKES AND VFR CONDITIONS SHOULD
PREVAIL THROUGH THIS MORNING. THE SYSTEM IN THE GREAT LAKES
SHOULD TRACK ACROSS OUR REGION THROUGH THE DAY AND EVENING. AN
AREA OF LIGHT RAIN SHOULD TRACK ACROSS CENTRAL AND SOUTHERN AREAS
FROM ABOUT 17Z THROUGH ABOUT 01Z. THE NORTHERN PERIPHERY OF THE
STEADIER RAIN SHOULD BE ABOUT KALB AND KPSF. HOWEVER...PUTTING
VCSH IN KGFL. SOME TEMPO MVFR CEILINGS AND VISIBILITIES ARE
POSSIBLE DURING THE RAIN AT KALB...KPSF ANDK POU THIS AFTERNOON
ADN EARLY EVENING. THE EXACT END OF THE RAIN IS UNKNOWN BUT KEPT
VCSH THROUGH 06Z AT ALL SITES UNTIL THE EXACT TIMING OF THE EXIT
OF THE RAIN IS KNOWN.
WINDS SHOULD BE LIGHT EAST TO NORTHEAST AT 5 KT OR LESS TROUGH THE
TAF PERIOD ENDING AT 06Z TOMORROW.
OUTLOOK...
TUE...MAINLY VFR. CHANCES -SHRA INCREASING AS THE DAY PROGRESSES
WITH THE BEST CHANCE AT KPOU.
TUE NIGHT-WED...VFR/MVFR. CHC -SHRA ESPECIALLY SOUTH OF KALB.
THU-FRI...VFR. NO SIG WX.
SAT...VFR. SLGT CHC -SHRA.
&&
.FIRE WEATHER...
FIRE WEATHER RELATED CONCERNS SHOULD REMAIN MINIMAL OVER THE NEXT
3 DAYS DUE TO LIGHT WINDS AND PERSISTENT HIGH RELATIVE
HUMIDITIES. REFER TO LATEST FWFALY FOR MORE SPECIFIC DETAILS.
&&
.HYDROLOGY...
RAINFALL AMTS SHOULD GENERALLY BE ONE QUARTER...TO ONE HALF OF AN
INCH FOR AREAS NEAR AND TO THE SOUTH/WEST OF THE GREATER CAPITAL
REGION THROUGH THURSDAY...WITH LESS THAN ONE QUARTER OF AN INCH
TO THE NORTH AND EAST. SOME MINOR...WITHIN BANK RISES ARE POSSIBLE
FOR AREAS WHERE RAINFALL AMTS REACH ONE HALF INCH OR
GREATER...SUCH AS ON THE ESOPUS...RONDOUT AND SCHOHARIE CREEKS.
GENERALLY DRY CONDITIONS ARE EXPECTED FOR LATE THURSDAY THROUGH
AT LEAST EARLY SATURDAY.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
FIRE WEATHER...KL
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS ALBANY NY
454 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TODAY AND
TONIGHT...AS A WEAK WAVE OF LOW PRESSURE TRAVELS ALONG IT. THIS WILL
BRING CLOUDS AND SOME RAIN TO THE REGION THROUGH WEDNESDAY
MORNING...WITH THE BEST CHANCE OF RAIN EXPECTED FROM THE GREATER
CAPITAL REGION AND AREAS SOUTH AND WEST. TEMPERATURES WILL REMAIN
SOMEWHAT COOL DUE TO CLOUDS AND RAIN THROUGH WEDNESDAY...BEFORE
GRADUALLY WARMING FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 445 AM EDT...HIGH CLOUDS ARE GRADUALLY INCREASING ACROSS THE
REGION...WITH MID LEVEL CLOUDS SLOWLY APPROACHING FROM THE WEST.
TEMPS HAVE DROPPED INTO THE UPPER 30S TO LOWER 40S IN MOST
VALLEYS...WITH MID 30S ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS.
CLOUDS WILL CONTINUE TO INCREASE/THICKEN FROM W TO E THROUGH MID
MORNING. SOME SUNSHINE MAY BE DIMLY VISIBLE AT TIMES UNTIL
THEN...ESP FOR AREAS E OF THE HUDSON RIVER VALLEY...AND INTO
SOUTHERN VT.
AS ONE SHORTWAVE...CURRENTLY OVER LOWER MICHIGAN...TRANSLATES
EASTWARD TODAY...INCREASING ISENTROPIC LIFT TO THE EAST OF THIS
FEATURE SHOULD ALLOW RAIN TO EXPAND INTO WESTERN AND SOUTHERN
PORTIONS OF THE REGION BY MID TO LATE MORNING. 00Z/23 MODELS AND
03Z/SREFS HAVE TRENDED FURTHER NORTH WITH THE EXPECTED RAIN SHIELD
WITH THIS SYSTEM...AND THIS IS FURTHER SUPPORTED BY RECENT
UPSTREAM RADAR TRENDS...AS WELL AS THE LATEST HRRR MODEL.
THEREFORE...HAVE RAISED POPS INTO THE LIKELY RANGE FOR CENTRAL AND
SOUTHERN PORTIONS OF THE REGION...FOR THIS
AFTERNOON/EVENING...WITH THE NORTHERN EDGE OF LIKELY POPS JUST N
OF SARATOGA...AND INTO EXTREME SW VT. IT IS POSSIBLE THAT THIS
INITIAL SURGE OF RAINFALL WEAKENS A BIT UPON MOVING FURTHER E INTO
OUR REGION...AS IT OUTRUNS THE BEST LOW LEVEL MOISTURE TRANSPORT
CURRENTLY FEEDING INTO IT FROM THE OHIO VALLEY REGION.
HOWEVER...RENEWED SHOWERS/RAIN WILL LIKELY DEVELOP ON THE
NORTHERN PERIPHERY OF THE SHORTWAVE AS IT TRANSLATES NEAR OR JUST
S/W OF THE CAPITAL REGION LATER THIS AFTERNOON OR EARLY THIS
EVENING.
RAINFALL AMTS SHOULD BE GENERALLY LIGHT TO MODERATE...WITH AN AREA
OF ONE QUARTER...TO ONE HALF INCH EXPECTED JUST S/W OF THE CAPITAL
REGION...ACROSS THE SCHOHARIE VALLEY AND CATSKILLS. SOMEWHAT
HIGHER AMTS ARE POSSIBLE WITHIN ANY EMBEDDED BANDS THAT
DEVELOP...AS MID LEVEL FRONTOGENETICAL FORCING INCREASES LATER
THIS AFTERNOON.
SOME WEAK ELEVATED INSTABILITY WILL PASS ACROSS SOUTHERN AREAS
LATER THIS AFTERNOON...WHICH COULD SUPPORT A FEW RUMBLES OF
THUNDER. HOWEVER...OVERALL ELEVATED INSTABILITY LOOKS MUCH WEAKER
THAN WHAT OCCURRED UPSTREAM DURING THE OVERNIGHT HOURS WHERE SOME
CG LIGHTNING STRIKES WERE NOTED. SO...HAVE KEPT OUT MENTION OF
THUNDER AT THIS TIME.
FOR TEMPS...GIVEN THE EXPECTED INCREASE IN CLOUD COVER AND
EVENTUAL RAIN...HAVE SIDED CLOSER TO THE COOLER MET MOS IN MOST
AREAS...WITH MID TO UPPER 50S EXPECTED FOR MAX TEMPS. GIVEN
INITIAL DEWPOINTS IN THE LOWER 40S...WET BULB COOLING MAY ACTUALLY
ALLOW TEMPS TO FALL ONCE THE RAIN DEVELOPS LATER THIS MORNING INTO
THE AFTERNOON. SHOULD THE RAIN DEVELOP ANY SOONER...EVEN COOLER
MAX TEMPS WOULD BE POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...THE FIRST SHORTWAVE SHOULD TRANSLATE E/SE ACROSS THE
SOUTHERN HALF OF THE REGION THIS EVENING. THEN...A SECOND
SHORTWAVE SHOULD APPROACH SOUTHERN AREAS CLOSER TO DAYBREAK. THIS
SHOULD FAVOR SOUTHERN AREAS FOR THE BEST CHC FOR RAIN
OVERNIGHT...AFTER THE INITIAL SURGE OF LIGHT TO MODERATE RAINFALL
THIS EVENING. THEREFORE...WILL TREND LIKELY POPS SOUTHWARD THROUGH THE
EVENING AND OVERNIGHT HOURS. NORTHERN AREAS MAY ACTUALLY HAVE SOME
THIN SPOTS IN THE CLOUDS DEVELOP AT TIMES OVERNIGHT...WHICH COULD
ALLOW FOR COOLER TEMPS...AND SOME PATCHY FOG. HAVE GENERALLY SIDED
WITH A MAV/MET MOS BLEND...WHICH WERE FAIRLY CLOSE IN MOST AREAS.
WED-WED NT...MAIN FORCING MECHANISMS FOR LIFT SHOULD MOVE S AND E
OF REGION WED MORNING. IN THEIR WAKE...VERY LITTLE IN THE WAY OF
DYNAMICS WILL REMAIN. HOWEVER...LOW LEVEL MOISTURE AND WEAK LOW
LEVEL ISENTROPIC LIFT SHOULD PERSIST...AND MAY ACTUALLY INTENSIFY
WED NT. THEREFORE...WILL KEEP SOME SLIGHT CHC POPS FOR WED
AFTERNOON ACROSS SOUTHERN AREAS...THEN EXPAND POPS NORTHWARD...AND
INCLUDE CHC POPS ACROSS THE EASTERN CATSKILLS. THIS WILL BE FOR
LIGHT RAIN SHOWERS AND AREAS OF DRIZZLE IN THE PERSISTENT LOW
LEVEL ISENTROPIC LIFT...AND WELL AS FOR THE INTERACTION OF THE
HIGHER TERRAIN WITH THE MOIST AND LIGHT SE FLOW. FOR TEMPS...SIDED
CLOSER TO THE COOLER MET MOS AGAIN FOR WED...WITH MAINLY 55-60
EXPECTED IN MOST AREAS DUE TO CLOUDS AND SOME LIGHT RAIN/DRIZZLE.
FOR WED NT...SIDED CLOSER TO THE WARMER MET MOS...DUE TO EXPECTED
CLOUD COVER...WITH WIDESPREAD 40S TO LOWER 50S.
THU-THU NT...DESPITE STRONGLY RISING MID AND UPPER TROPOSPHERIC
HEIGHTS...A PERSISTENT MOIST SE FLOW MAY ACT TO KEEP LOW CLOUDS
AND SOME SPOTTY DRIZZLE FAIRLY PERSISTENT THROUGH THIS PERIOD. HAVE
THEREFORE SIDED CLOSER TO THE COOLER MET MOS...WITH GENERALLY
60-65 EXPECTED FOR MAXES...AND 40S TO LOWER 50S FOR MINS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
NOT A WHOLE LOT OF CHANGE TO THE LONG RANGE FORECAST WITH LOTS OF
SPREAD IN THE GUIDANCE AS TO HOW A POTENTIAL STORM ALONG THE EAST
COAST OF THE U.S EVOLVES. THE FIRST PART OF THE LONG RANGE
FORECAST...FRIDAY AND SATURDAY...LOOKS QUIET...WITH DRY WEATHER...
INCREASING CLOUD COVER AND HIGH TEMPERATURES IN THE 60S TO AROUND
70.
THERE COULD BE SOME ISOLATED SHOWERS ADVANCING INTO WESTERN
AREAS SATURDAY AFTERNOON DEPENDING ON THE TIMING OF THE APPROACH OF
A STRONG NORTHERN STREAM SYSTEM FROM THE MIDWEST AND GREAT LAKES.
THIS NORTHERN STREAM SYSTEM...COMBINED WITH HIGH AMPLITUDE UPPER
RIDGING JUST OFF THE CANADIAN COAST...IS PREDICTED TO INFLUENCE THE
MOVEMENT OF THE TROPICAL SYSTEM CURRENTLY DEVELOPING IN THE
CARIBBEAN.
DECENT CONSENSUS THAT THESE UPPER FEATURES WILL INTERACT WITH THE
TROPICAL SYSTEM...SUPPORTING NORTHWARD MOVEMENT. HOWEVER...THE EXACT
POSITION OF THESE STEERING FEATURES WILL DETERMINE WHETHER THE STORM
IMPACTS THE EASTERN U.S. OR STAYS MAINLY OUT TO SEA. SO...THE RANGE
OF POSSIBLE IMPACTS IS STILL ANYWHERE FROM NO IMPACT TO A
SIGNIFICANT IMPACT...BUT AN EXTREMELY UNUSUAL UPPER PATTERN
CONFIGURATION AND STORM TRACK WOULD BE REQUIRED FOR THE WORST CASE
SCENARIO OF HEAVY RAIN AND WINDS IN EASTERN AND NORTHERN NY AND
WESTERN NEW ENGLAND. STILL AT THE WAIT AND SEE STAGE FOR THIS
POTENTIAL SYSTEM...WHICH AGAIN COULD HAVE MINIMAL IMPACT OR
SIGNIFICANT IMPACT OR SOMETHING IN BETWEEN.
EVEN THE GUIDANCE THAT KEEPS THE STORM WELL OFFSHORE SHOWS OUR
REGION IN THE RIGHT ENTRANCE REGION OF A STRONG UPPER JET SEGMENT
AND DECENT BOUNDARY LAYER THERMAL GRADIENT ALONG A COLD FRONT...
ASSOCIATED WITH THE ADVANCING NORTHERN STREAM SYSTEM THAT COULD BE
GOING NEGATIVE TILT AND TRENDING TOWARD BECOMING A CUT OFF UPPER
LOW. SO EVEN IF WE DO NOT SEE A DIRECT IMPACT FROM THE STORM...SOME
ENHANCED RAINFALL ALONG THE COLD FRONT...AND WITHIN THE REGION OF
STRONG UPPER DYNAMICS...COULD OCCUR SATURDAY NIGHT THROUGH MONDAY.
JUST INDICATING CLOUDY WITH CHANCES OF RAIN SATURDAY NIGHT THROUGH
MONDAY WITH HIGHS IN THE MID 50S TO LOWER 60S SUNDAY AND UPPER 40S
TO MID 50S MONDAY.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
SOME HIGH THIN CLOUDS ARE SPREADING ACROSS THE REGION AHEAD OF AN
UPPER LEVEL SYSTEM IN THE GREAT LAKES AND VFR CONDITIONS SHOULD
PREVAIL THROUGH THIS MORNING. THE SYSTEM IN THE GREAT LAKES
SHOULD TRACK ACROSS OUR REGION THROUGH THE DAY AND EVENING. AN
AREA OF LIGHT RAIN SHOULD TRACK ACROSS CENTRAL AND SOUTHERN AREAS
FROM ABOUT 17Z THROUGH ABOUT 01Z. THE NORTHERN PERIPHERY OF THE
STEADIER RAIN SHOULD BE ABOUT KALB AND KPSF. HOWEVER...PUTTING
VCSH IN KGFL. SOME TEMPO MVFR CEILINGS AND VISIBILITIES ARE
POSSIBLE DURING THE RAIN AT KALB...KPSF ANDK POU THIS AFTERNOON
ADN EARLY EVENING. THE EXACT END OF THE RAIN IS UNKNOWN BUT KEPT
VCSH THROUGH 06Z AT ALL SITES UNTIL THE EXACT TIMING OF THE EXIT
OF THE RAIN IS KNOWN.
WINDS SHOULD BE LIGHT EAST TO NORTHEAST AT 5 KT OR LESS TROUGH THE
TAF PERIOD ENDING AT 06Z TOMORROW.
OUTLOOK...
TUE...MAINLY VFR. CHANCES -SHRA INCREASING AS THE DAY PROGRESSES
WITH THE BEST CHANCE AT KPOU.
TUE NIGHT-WED...VFR/MVFR. CHC -SHRA ESPECIALLY SOUTH OF KALB.
THU-FRI...VFR. NO SIG WX.
SAT...VFR. SLGT CHC -SHRA.
&&
.FIRE WEATHER...
FIRE WEATHER RELATED CONCERNS SHOULD REMAIN MINIMAL OVER THE NEXT
3 DAYS DUE TO LIGHT WINDS AND PERSISTENT HIGH RELATIVE
HUMIDITIES. REFER TO LATEST FWFALY FOR MORE SPECIFIC DETAILS.
&&
.HYDROLOGY...
RAINFALL AMTS SHOULD GENERALLY BE ONE QUARTER...TO ONE HALF OF AN
INCH FOR AREAS NEAR AND TO THE SOUTH/WEST OF THE GREATER CAPITAL
REGION THROUGH THURSDAY...WITH LESS THAN ONE QUARTER OF AN INCH
TO THE NORTH AND EAST. SOME MINOR...WITHIN BANK RISES ARE POSSIBLE
FOR AREAS WHERE RAINFALL AMTS REACH ONE HALF INCH OR
GREATER...SUCH AS ON THE ESOPUS...RONDOUT AND SCHOHARIE CREEKS.
GENERALLY DRY CONDITIONS ARE EXPECTED FOR LATE THURSDAY THROUGH
AT LEAST EARLY SATURDAY.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
FIRE WEATHER...KL
HYDROLOGY...KL
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1211 PM CDT TUE OCT 23 2012
.DISCUSSION...
ISSUED 1036 AM CDT TUE OCT 23 2012
HAVE MADE TWEEKS TO TEMPS TODAY AND ADDED CHC POPS IN SOUTHEAST
FOR EARLY THIS AFTERNOON.
SHORTWAVE MOVING THROUGH AREA CURRENTLY IS ENHANCING PCPN
COVERAGE AND INTENSITY...PARTICULARLY SOUTHEAST HALF OF FORECAST
AREA. WAVE SHOULD MOVE PAST AREA EARLY THIS AFTERNOON AND
SHORTWAVE RIDGING SHOULD BUILD HEIGHTS AND ALLOW FOR SIGNIFICANT
SUBSIDENCE TO BRING AN END TO PCPN AND SOME BREAKS IN CLOUDS. THE
SLOWEST AREA OF IMPROVEMENT WILL LIKELY BE IN THE SOUTHEAST WHERE
REMNANT PCPN MAY LINGER AS AREA OF SHOWERS FORMED AT NOSE OF LOW-
LEVEL JET IN ERN MISSOURI MOVES EAST. ELSEWHERE...CAPPING SHOULD
INHIBIT ADDITIONAL DEVELOPMENT.
BREAKS IN CLOUDS SHOULD ALLOW TEMPS TO RESPOND. TEMPS ACROSS
SOUTHERN ILLINOIS ALREADY NEAR 70F AND WITH SOME SUN AND SOUTH
WINDS ADVECTING IN WARMER TEMPS...70S STILL LIKELY.
&&
.AVIATION...
ISSUED 1159 AM CDT TUE OCT 23 2012
SUBSIDENCE BEHIND SHORTWAVE MOVING THROUGH ILLINOIS AT PRESENT
SHOULD DIMINISH REMAINING PRECIP THIS AFTERNOON AND ALLOW FOR
ADDITIONAL BREAKS IN IFR CIGS. HOWEVER...ABUNDANT MOISTURE EVIDENT
IN MVFR OVERCAST TO WEST WILL LIKELY PUSH EAST OVERNIGHT IMPACTING
CENTRAL ILLINOIS TERMINALS. WILL BRING IN MVFR CIGS AND LINGER
UNTIL MIXING ALLOWS SOME LIFTING MIDMORNING WEDNESDAY.
WITH SOME PARTIAL CLEARING...SOUTH WINDS WILL LIKELY DEVELOP SOME
GUSTING LATE THIS AFTERNOON. SOME GUSTING WILL ONCE AGAIN DEVELOP
WITH LIFTING CIGS ON WEDNESDAY MORNING.
BARKER
&&
.PREV DISCUSSION...
ISSUED 310 AM CDT TUE OCT 23 2012
WARM FRONT CURRENTLY LOCATED OVER NORTHERN ILLINOIS...ROUGHLY
ALONG THE I-80 CORRIDOR. HAVE BEEN SEEING SHOWERS AND STORMS
INCREASING ACROSS WESTERN ILLINOIS AND ESPECIALLY OVER
MISSOURI...AS AN UPPER WAVE MOVES INTO THE AREA AND AN APPARENT
MESOSCALE VORTEX TRACKS ACROSS MISSOURI PER WATER VAPOR IMAGERY.
INITIAL FORECAST CONCERN INVOLVES CONVECTIVE TRENDS FOR PRIMARILY
THIS MORNING...ALONG WITH ITS EFFECTS ON TEMPERATURES. IN THE
LONGER RANGE...THE TIMING OF A STRONG COLD FRONT ON THURSDAY
REMAINS AN ISSUE...ALONG WITH RAIN TRENDS THURSDAY AND FRIDAY.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST HRRR DOING A REASONABLE JOB WITH THE CONVECTION OVER
MISSOURI...AND IT CONTINUES TO INCREASE THE RAIN OVER MOST OF THE
CWA THROUGH EARLY MORNING. AS SUCH...HAVE RAMPED UP RAIN CHANCES
TO THE LIKELY RANGE IN MOST AREAS...PRIMARILY ALONG AND EAST OF
I-55. ANY LINGERING RAIN SHOULD BE TAPERING OFF EARLY IN THE
AFTERNOON. THE CONVECTION YESTERDAY REALLY THREW OFF THE HIGH
TEMPERATURE FORECAST...AND WILL HAVE TO KEEP THAT POTENTIAL IN
MIND FOR TODAY...ESPECIALLY IF CLOUDS ARE SLOW TO MOVE OUT. HAVE
LOWERED HIGHS FOR TODAY BY A FEW DEGREES IN MOST AREAS...CLOSER TO
A MET/MAV BLEND. HOWEVER...HAVE KEPT HIGHS NEAR 80 DEGREES ON
WEDNESDAY AND OVER THE EASTERN 2/3 OF THE CWA ON THURSDAY AS WELL.
UPPER WAVE CURRENTLY OVER THE PACIFIC NORTHWEST IS EXPECTED TO
FORM A CLOSED LOW AS IT MOVES NORTHEAST TO THE CANADIAN PRAIRIES
BY EARLY WEDNESDAY. 50-70 KNOT JET AT 500 MB WILL FOLLOW A WAVE
SLIDING ALONG THE SOUTHERN JET STREAM TO FEED INTO THE AREA AHEAD
OF THE COLD FRONT. LATEST MODEL GUIDANCE BRINGS THE FRONT INTO THE
NORTHWESTERN CWA THURSDAY AFTERNOON...AND ENTERING THE SOUTHEAST
CWA TOWARD MIDNIGHT. A NARROW WINDOW OF OPPORTUNITY EXISTS FOR
SOME STRONGER STORMS AHEAD OF THE FRONT THURSDAY AFTERNOON...
ALTHOUGH RAPIDLY INCREASING CLOUDS MAY THWART THIS POTENTIAL.
HOWEVER...THE RAIN WILL BE ON THE INCREASE...AND HAVE INTRODUCED
LIKELY POPS NORTHWEST OF THE ILLINOIS RIVER DURING THE AFTERNOON.
WITH THE BULK OF THE RAIN BEHIND THE FRONT...WILL SPREAD THE
LIKELY POPS FROM WEST TO EAST...WITH THE RAIN DIMINISHING WEST OF
I-55 AFTER MIDNIGHT.
LONG TERM...FRIDAY THROUGH MONDAY...
MODELS HAVE BEEN BACKING OFF ON THE IDEA OF A SECONDARY WAVE
FEEDING THE AREA BEHIND THE FRONT...WITH THE 00Z ECMWF THE ONLY
ONE STILL WITH THIS GENERAL TREND. WILL DROP THE RAIN CHANCES
NORTHWEST OF THE ILLINOIS RIVER ON FRIDAY AND FRIDAY NIGHT...AND
LOWER THEM QUITE A BIT FURTHER EAST. HOWEVER...THE GFS AND
CANADIAN MODELS WOULD SUGGEST COMPLETELY DRY CONDITIONS BY EARLY
FRIDAY EVENING EVERYWHERE...SO WILL NEED TO SEE IF THIS TREND
CONTINUES. HAVE REMOVED THE RAIN ON SATURDAY ASIDE FROM SOME
SLIGHT CHANCES EAST OF I-57...MAINLY DURING THE MORNING.
WEEKEND TREND STILL LOOKS QUITE CHILLY...WITH HIGHS IN MANY AREAS
STRUGGLING TO REACH THE 50 DEGREE MARK. SUB-FREEZING LOWS ARE
EXPECTED ALONG AND WEST OF I-55 BY SUNDAY MORNING. BEYOND
THAT...THE FORECAST TRENDS BECOME COMPLICATED BY A TROPICAL SYSTEM
MOVING NORTHWARD OFF THE EAST COAST. ECMWF MODEL IS MORE AFFECTED
AND FORMS A CUTOFF LOW OVER THE GREAT LAKES...LINGERING THE CHILLY
WEATHER INTO EARLY NEXT WEEK...WHEREAS THE GFS IS MORE PROGRESSIVE
AND MILDER. NEITHER SOLUTION CURRENTLY YIELDS ANY PRECIPITATION
FOR OUR AREA SUNDAY AND MONDAY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1141 AM CDT TUE OCT 23 2012
.DISCUSSION...
858 AM CDT
UPDATED GRIDS AND ZFP HAVE BEEN SENT WITH SIGNIFICANT CHANGES TO
FIRST PERIOD.
MORNING WATER VAPOR IMAGERY SHOWS A WELL DEFINED SHORTWAVE TROUGH
MOVING EASTWARD OVER IA/MO. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS LIKELY TO CONTINUE TO PERCOLATE IN THE VERY MOIST
AIRMASS OUT AHEAD OF THIS SHORTWAVE. MAJORITY OF THE ASCENT WITH
THIS WAVE SHOULD BE EAST OF THE CWA BY LATE AFTERNOON WITH SHOWER
AND THUNDERSTORM COVERAGE EXPECTED TO DECREASE TOWARD EVENING.
HAVE BUMPED UP SKY COVER CONSIDERABLY TODAY WITH NO HOPE OF SEEING
ANY BREAKS IN THE OVERCAST UNTIL THIS SHORTWAVE PASSES EAST OF THE
AREA LATE THIS AFTERNOON. EVEN THEN ONCE THE MID/HIGH LEVEL
MOISTURE CLEARS OUT THINKING ITS VERY LIKELY STRATUS DECK WILL
STICK AROUND AS OUR LATE OCTOBER SUN ANGLE IS ROUGHLY THE SAME AS
EARLY FEBRUARY AND WITH SUCH LATE CLEARING OF HIGH CLOUDS AND VERY
MOIST LOW LEVELS THINK IT WILL BE TOO LITTLE TOO LATE FOR THE SUN
TO EAT AWAY AT THE STRATUS. IN FACT...THERE IS A VERY REAL CHANCE
THAT STRATUS COULD STICK AROUND TONIGHT INTO TOMORROW MORNING AS
WELL AND HAVE BUMPED UP SKY GRIDS SOME TONIGHT. AFTERNOON FORECAST
MAY NEED TO CONSIDER ADJUSTING SKY COVER UP FURTHER TONIGHT INTO
TOMORROW.
GIVEN THE ANTICIPATED THICK OVERCAST MOST OF TODAY HAVE TAKEN A
HATCHET TO THE GOING HIGH TEMPERATURE FORECAST. GENERALLY WOULD
EXPECT TEMPS TO REMAIN NEARLY STEADY MOST OF THE DAY IN THE LOW TO
MID 60S...WITH A COUPLE/FEW DEGREE TEMP RISE POSSIBLE LATE THIS
AFTERNOON...ESPECIALLY FAR WESTERN CWA WHICH COULD POSSIBLY MAKE
A RUN AT 70 DEGREES STILL.
IZZI
//PREV DISCUSSION...
326 AM CDT
EARLY THIS MORNING THE FRONTAL BOUNDARY HAS STALLED ACROSS THE IL/WI
STATELINE. TO THE NORTH OF THE BOUNDARY TEMPS HAVE HELD IN THE
MID/UPR 50S WITH DEW PTS IN THE LOW/MID 50S WITH AREAS OF DENSE FOG.
SOUTH OF THE BOUNDARY TEMPS HAVE REMAINED VERY MILD FOR MID OCTOBER
IN THE 60S...ALONG WITH ANOMALOUSLY HIGH DEW PTS OF AROUND 60. IR
IMAGERY EARLY THIS MORNING DEPICTED THE LEADING EDGE OF HIGH BASED
CLOUDS FLOATING NORTH ALONG A CENTRAL IOWA...NORTHERN IL...TO FAR
SOUTHWEST LOWER MICHIGAN LINE. THIS AREA OF HIGH CLOUDS AND VERY
MOIST AIRMASS WAS ASSOCIATED WITH AN ELEVATED SHORTWAVE LIFTING
NORTHEAST ACROSS SOUTHWEST MISSOURI. SHOWERS AND THUNDERSTORMS HAVE
BEEN STEADILY GROWING IN COVERAGE ACROSS MISSOURI...AND BASED ON
CURRENT TRAJECTORIES THE LEADING PRECIP SHOULD ARRIVE ALONG THE
SOUTHWEST CWFA AROUND DAYBREAK. THEN STEADILY LIFT NORTHEAST ACROSS
THE REMAINING CWFA BY MID-MORNING. CURRENT GUIDANCE INDICATES CAPE
OF AROUND 500-750J/KG IN THE 15-18 TIMEFRAME...WHICH APPEARS TO BE
THE HIGHEST CONFIDENCE TIMING FOR CONVECTION TO OCCUR. SO HAVE
CARRIED LIKELY SHRA/TSRA AT THAT TIME.
AS THE ELEVATED WAVE ARRIVES ACROSS THE CWFA THIS MORNING...IT WILL
REMAIN PROGRESSIVE AND ALLOW PRECIP TO DIMINISH IN COVERAGE FROM
SOUTH TO NORTH ACROSS THE CWFA THIS AFTN. SUPPORTING THIS DRYING
TREND WILL BE THE SLOW RISE IN HEIGHTS ALOFT...INDICATING WEAK
DIFFLUENCE ALOFT.
WITH REGARDS TO TEMPS TODAY...GUIDANCE IS DEMONSTRATING A HIGHER
CONFIDENCE THAT TEMPS WILL EASILY WARM INTO THE 70S. THE CHALLENGE
IS DETERMINE THE LOCATIONS THAT WILL WARM INTO THE MID 70S...WHICH
CURRENTLY APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO KANKAKEE
LINE. THE OTHER WILDCARD FOR LOCATIONS NORTH OF THIS LINE WILL BE
THE CLOUD COVER AND LINGERING PRECIP. AT THIS TIME IT APPEARS BY 21Z
ALL BUT A FEW SHRA SHOULD HAVE DEPARTED THE CWFA TO THE
NORTH...ALTHOUGH CLOUDS MAY STILL BE MOSTLY CLOUDY. PWAT VALUES WILL
REMAIN ABOVE 1 INCH THRU THE DAY TDY...WITH A HANDFUL OF LOCATIONS
RISING TO NEARLY 1.5 INCHES. THE COMBINATION OF MILD TEMPS AND HIGH
MOISTURE CONTENT IN THE ATMOSPHERE WILL MAKE TODAY AND WED FEEL MORE
LIKE SUMMER.
SOUTHERLY FLOW WILL LINGER THROUGH THE OVERNIGHT...AND SHOULD BE
JUST STRONG ENOUGH TO PREVENT DENSE FG FROM FORMING. THUS WILL ONLY
MENTION PATCHY FG IN THE FORECAST TONIGHT. ANOTHER MILD NIGHT
APPEARS LIKELY FOR TONIGHT WITH TEMPS ONLY COOLING INTO THE LOW 60S.
A FEW GUIDANCE MEMBERS WERE WARMER THAN THIS IN THE MID 60S AT A
HANDFUL OF POINTS...HOWEVER FELT THE GENERAL CONSENSUS WOULD BE
AROUND 60 TO PSBLY LOW 60S. DRY WEATHER SHOULD LAST THROUGH THE
OVERNIGHT HOURS AS WELL.
WEDNESDAY THROUGH THURSDAY...
500MB RIDGE PUSHES OVERHEAD WITH WEAK DIFFLUENT FLOW IN THE
LLVLS...SUGGESTING MUCH OF WED THRU AT LEAST DAYBREAK THUR WILL
REMAIN DRY. FOR WED THIS WILL SET THE STAGE FOR A RUN AT TEMPS
AROUND 80...PSBLY WARMING INTO THE LOW 80S FOR A FEW LOCATIONS WED
AFTN. THE DEEPER MOISTURE WILL PEEL OFF TO THE NORTHEAST WITH THE
WARM FRONTAL BOUNDARY...WHICH MAY AID IN SLIGHTLY LOWER DEW PTS AND
PWAT VALUES HOVER AROUND 1 INCH WED AFTN. IF DEW PTS CAN FALL INTO
THE MID/UPR 50S...THIS WOULD ALLOW THE SFC TO WARM MORE EFFICIENTLY
AND ALLOW THE SFC TO EASILY REACH 80 DEG IN MANY LOCATIONS OF THE
CWFA. CURRENT TEMP PLUMES FROM THE SREF AND VARIOUS OTHER GUIDANCE
SOURCES...INDICATE TEMPS WED WILL BE IN THE MID/UPR 70S OVER THE FAR
NORTHERN TIER OF COUNTIES IN IL. MEANWHILE FURTHER SOUTH OR SOUTH OF
I-88...TEMPS COULD WARM INTO THE UPR 70S TO AROUND 80. CLOUDS WILL
ALSO PLAY A ROLE...HOWEVER CURRENTLY FORECASTING P-CLOUDY CONDS WED.
THEN FOR THUR AHEAD OF THE FRONTAL BNDRY...TEMPS COULD WARM AGAIN
INTO THE MID/UPR 70S MAINLY FOR FAR EASTERN SECTIONS OF THE CWFA.
500MB TROUGH AXIS WILL BEGIN TO PUSH INTO THE CENTRAL PLAINS WED
NGT/EARLY THUR...WITH THE MAIN VORT MAX ROUNDING THE TROUGH AXIS
EARLY THUR MORNING ACROSS THE SOUTHERN PLAINS. IT APPEARS THAT THE
DOWNSTREAM RIDGE WILL EXTEND FROM QUEBEC TO THE CAROLINAS...WHICH
MAY ALLOW THE FRONTAL BNDRY TO SLOW SLIGHTLY. IF THE BNDRY SLOWS
FURTHER...PRECIP COULD REMAIN WEST OF THE CWFA THRU THE EARLY AFTN
HOURS AND ALLOW TEMPS TO BE EVEN WARMER...GIVEN THE POTENTIAL FOR
COMPRESSIONAL HEATING TO OCCUR BETWEEN THE DEPARTING SFC RIDGE AND
UPSTREAM TROUGH.
INSTABILITY WILL DEVELOP WITH THE PASSAGE THUR AFTN...THEN SHUD
STABILIZE IN THE EVENING HOURS WITH FRONTAL PASSAGE. WINDS WILL TURN
NW...WITH MUCH COOLER AIR STEADILY ADVECTING ACROSS THE CWFA.
THERMAL RIDGE OF 15 TO 17 DEG C AT 850MB RAPIDLY TRANSITIONS TO
AROUND 5 DEG C BY 06Z FRI.
FRIDAY THROUGH MONDAY...
POTENT ANTI-CYCLONIC FLOW QUICKLY ARRIVES FRI...AND SHUD PUSH THE
PRECIP/CLOUDS TO THE EAST ACROSS IN/MI. HOWEVER A FEW EASTERN AREAS
COULD CONTINUE TO SEE A SLIGHT CHC POPS FRI. FRI APPEARS TO BE THE
WARMEST DAY IN THE FINAL PERIODS OF THE EXTENDED...WITH TEMPS
EXPECTED TO BE IN THE LOW 50S. THESE HIGH TEMPS MAY ACTUALLY ARRIVE
EARLY IN THE DAY...AS COLD AIR CONTINUES TO POUR IN FROM THE
NORTHWEST THROUGHOUT THE DAY.
LAKE EFFECT CONDS DEVELOP AND BECOME OPTIMAL FRI NGT/SAT/SAT NGT FOR
THE FAVORED AREAS OF NORTHWEST IN. THERMAL TROUGH OVERHEAD WILL
CONTINUE TO COOL WITH 0 TO -3 DEG C AT 850MB POISED TO PUSH OVERHEAD
SAT/SUN. THUS IT APPEARS TEMPS WILL STRUGGLE TO WARM BEYOND THE
LOW/MID 40S. AT THIS TIME IT DOES NOT APPEAR CLOUDS WILL BE A MAJOR
PLAYER. IN ADDITION DRY WEATHER SHOULD REMAIN THRU THE BULK OF THE
EXTENDED...WITH THE EXCEPTION OF NORTHWEST IN. ANY LINGERING PRECIP
DURING THE NOCTURNAL HOURS FRI/SAT/SUN COULD BECOME MIXED WITH SOME
WET SNOW...AS TEMPS WILL BE COOLING INTO THE MID 30S EACH OF THESE
NIGHTS. SAT NGT COULD BE THE COOLEST DAY AS GUIDANCE HAS INDICATED
THE SFC RIDGE PUSHING OVER CENTRAL WI. THIS COULD ALLOW WINDS TO
DIMINISH AND CLOUDS TO REMAIN MINIMAL...ALLOWING FOR OPTIMAL
RADIATIONAL COOLING TO TAKE PLAY SAT NGT. IF THIS SCENARIO WERE TO
VERIFY...TEMPS COULD EASILY BOTTOMOUT IN THE UPR 20S ACROSS THE
CWFA.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* IFR INTO EARLY AFTERNOON.
* WIND CONTINUING TO VEER FROM SE TO S AND SSW REST OF A.M. AND
EARLY THIS AFTERNOON.
* SCT -SHRA TIL EARLY-MID AFTERNOON. FEW SMALL TS IN AREA.
TRS
//DISCUSSION...UPDATED 16Z...
WARM FRONT HAS SLOWLY MOVED N DURING THE LATE MORNING AND HAD
REACHED ORD AT 16Z. WITH THE WIND VEERING TO SOUTHERLY VISIBILITY
AND CEILINGS HAVE IMPROVED. MDW GOT UP TO 020 THEN LOWERED BACK TO
014 AS A SHOWER JUST CLIPPED THE AIRFIELD. EXPECT CEILINGS THERE
TO RISE AGAIN WITHIN NEXT HR OR SO.
ADDITIONAL SHOWERS WITH A FEW HEAVIER SMALL CELLS HAVE BEEN MOVING
NE INTO N CENTRAL IL WITH EXTRAPOLATION OF RECENT MOVEMENT HAVING
THEM ARRIVE IN THE ORD AND MDW VC 17-18Z. NO ORGANIZATION IN THIS
ACTIVITY SEEN AND MAX TOPS REMAINING AOB 250 SO HAVE ONLY INCLUDED
MENTION OF VCSH AND NO TS IN TAFORS FOR THE AFTERNOON.
TRS
PREVIOUS DISCUSSION...UPDATED 14Z...
TROUGH/WARM FRONT HAS NOT LIFTED NORTHWARD AS SOON AS MODELS
EARLIER INDICATED AND EVEN LATEST AVAILABLE HI RES HRRR AND RAP
PLACE IT TOO FAR N NEAR/TO WI BORDER BY 15-16Z WHICH LOOKS TO BE
A COUPLE HRS TOO FAST. LIFR AND IFR EXPECTED TO PERSIST TIL
BOUNDARY DOES LIFT N PAST TERMINALS AND WINDS BECOME SOUTHERLY
BTWN 17Z-19Z THEN CIGS SHUD LIFT AND VSBYS IMPROVE.
BETWEEN AREA OF RA AND TS MOVING ENE OVER NRN IN AND ANOTHER AREA
OF MAINLY RA AND A FEW TS MOVING SLIGHTLY N OF E FM ERN MO ACROSS
THE MS RIVER ARE SCT DISORGANIZED -SHRA AND ISOLD SHRA. MODELS
SHOW BULK OF QPF E OF LOCAL TERMINALS BY 18Z AS UPPER TROUGH FROM
NRN MO SSE TO NORTHEASTERN AR MOVES OVER AND PAST THE LOCAL AREA.
MODELS DO INDICATE SPOTTY QPF 18Z-00Z BUT AMOUNTS OF ONLY A
COUPLE HUNDREDTHS OF AN INCH. DO NOT SEE ANY SIGNIFICANT FORCING
MECHANISMS FOR ADDITIONAL SHRA GENERATION BEYOND EARLY AFTERNOON.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
TWO MAIN CONCERNS/CHALLENGES...CIGS AND TSRA THIS MORNING. LIFR
CIGS HAVE REMAINED LOCKED IN AND WITH CONTINUED LIGHT NORTHEAST
WINDS OFF THE LAKE...EXPECT AT LEAST A FEW MORE HOURS OF LIFR CIGS
UNTIL WINDS START TO TURN MORE SOUTHERLY AND CIGS LIFT. CONFIDENCE
REGARDING TIMING REMAINS LOW. ONCE CIGS DO LIFT...MVFR CIGS LIKELY
TO CONTINUE INTO THE EARLY/MID AFTERNOON.
ONE COMPLEX OF TSRA OVER EASTERN IL/WESTERN INDIANA WILL REMAIN
SOUTH OF THE TERMINALS WHILE CONVECTION OVER MISSOURI HAS WEAKENED
CONSIDERABLY IN THE PAST FEW HOURS. SHORT TERM GUIDANCE STILL
SUGGESTS FURTHER SHRA DEVELOPMENT ACROSS WESTERN IL THIS MORNING
BUT CONFIDENCE REGARDING TSRA POTENTIAL IS DECREASING AND TRENDS
WILL NEED TO BE MONITORED FOR POSSIBLE UPDATES.
SOUTHERLY WINDS MAY GUST INTO THE MID TEENS THIS AFTERNOON BUT
THIS WILL BE DEPENDENT ON SUNSHINE AND LOW LEVEL MIXING WHICH MAY
NOT OCCUR. SOUTHERLY WINDS WILL PERSIST TONIGHT AND SHOULD BEGIN
TO GUST SOME WEDNESDAY MORNING. WITH THE WARM FRONT EXPECTED TO BE
WELL NORTH OF THE AREA TONIGHT...NOT EXPECTING ANY WIDESPREAD FOG
OR LOW CIG PROBLEMS BUT HAVE INCLUDED SOME MVFR VIS AT RFD/DPA.
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE CIGS WILL LIFT TO ABV 020 BY EARLY AFTERNOON.
* MEDIUM CONFIDENCE THAT NO ADDITIONAL TS AT/VC TERMINALS THIS
AFTERNOON.
* HIGH CONFIDENCE WIND DIRECTION WILL REMAIN S-SSW.
* MEDIUM CONFIDENCE WINDS WILL BE IN 05-10 KT RANGE.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...VFR.
* THURSDAY...STRONG/GUSTY SOUTHWEST WINDS. SHRA/TSRA THURSDAY
AFTERNOON/EARLY EVENING...ALONG/AHEAD OF WIND SHIFT/COLD FRONT.
* FRIDAY AND SATURDAY...SLIGHT CHANCE OF SHRA.
* SUNDAY AND MONDAY...VFR.
&&
.MARINE...
308 AM...A FRONTAL BOUNDARY HAS BECOME NEARLY STATIONARY JUST
SOUTH OF LAKE MICHIGAN EARLY THIS MORNING. IT WILL BEGIN TO SLOWLY
LIFT NORTH LATER TODAY AND TONIGHT AS LOW PRESSURE OVER THE
NORTHERN PLAINS LIFTS NORTH INTO SOUTHERN CANADA. HOWEVER...WITH
HIGH PRESSURE ACROSS ONTARIO...THE GRADIENT WILL REMAIN FAIRLY
STRONG ACROSS THE NORTHERN THIRD OR QUARTER OF THE LAKE WITH
EASTERLY WINDS 15-25 KTS INTO TONIGHT...SLOWLY TURNING SOUTHEAST
AND WEAKENING BY WEDNESDAY MORNING. NEW LOW PRESSURE WILL DEVELOP
OVER EASTERN COLORADO TONIGHT AND MOVE NORTHEAST TO NEAR LAKE
SUPERIOR BY THURSDAY AFTERNOON. THE GRADIENT WILL STEADILY TIGHTEN
AHEAD OF THIS FRONT WEDNESDAY NIGHT INTO THURSDAY MORNING BUT
FORECAST SOUNDINGS SHOW A FAIRLY STRONG MARINE LAYER/INVERSION.
BUT WINDS STILL EXPECTED TO REACH 30 KTS OR SO. WINDS WILL
DIMINISH AHEAD OF THE COLD FRONT LATE THURSDAY AFTERNOON/EARLY
THURSDAY EVENING THEN SHIFT OUT OF THE NORTHWEST BEHIND THE FRONT.
WITH HIGH PRESSURE BUILDING ACROSS THE PLAINS...THE GRADIENT
BEHIND THE FRONT WILL LIKELY SUPPORT GUSTS TO 30 KTS. COULD BE AN
HOUR OR TWO OF HIGHER GUSTS WITH/JUST BEHIND THE FRONT.
LIGHT WINDS ACROSS THE SOUTHERN TWO THIRDS OF THE LAKE...COMBINED
WITH THE VERY MOIST LOW LEVELS WILL LIKELY LEAD TO AREAS OF FOG
AND MAYBE SOME PATCHY DENSE FOG...THIS MORNING WHICH SHOULD
IMPROVE AS WINDS TURN MORE SOUTHERLY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878
UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1036 AM CDT TUE OCT 23 2012
.DISCUSSION...
ISSUED 1036 AM CDT TUE OCT 23 2012
HAVE MADE TWEEKS TO TEMPS TODAY AND ADDED CHC POPS IN SOUTHEAST
FOR EARLY THIS AFTERNOON.
SHORTWAVE MOVING THROUGH AREA CURRENTLY IS ENHANCING PCPN
COVERAGE AND INTENSITY...PARTICULARLY SOUTHEAST HALF OF FORECAST
AREA. WAVE SHOULD MOVE PAST AREA EARLY THIS AFTERNOON AND
SHORTWAVE RIDGING SHOULD BUILD HEIGHTS AND ALLOW FOR SIGNIFICANT
SUBSIDENCE TO BRING AN END TO PCPN AND SOME BREAKS IN CLOUDS. THE
SLOWEST AREA OF IMPROVEMENT WILL LIKELY BE IN THE SOUTHEAST WHERE
REMNANT PCPN MAY LINGER AS AREA OF SHOWERS FORMED AT NOSE OF LOW-
LEVEL JET IN ERN MISSOURI MOVES EAST. ELSEWHERE...CAPPING SHOULD
INHIBIT ADDITIONAL DEVELOPMENT.
BREAKS IN CLOUDS SHOULD ALLOW TEMPS TO RESPOND. TEMPS ACROSS
SOUTHERN ILLINOIS ALREADY NEAR 70F AND WITH SOME SUN AND SOUTH
WINDS ADVECTING IN WARMER TEMPS...70S STILL LIKELY.
BARKER
&&
.AVIATION...
ISSUED 648 AM CDT TUE OCT 23 2012
WILL BE A BREAK IN THE PCPN THIS MORNING AS AREA WILL BE IN
BETWEEN COMPLEXES. THE NEXT ROUND OF PCPN SHOULD REACH SPI/PIA
AROUND 15Z...DEC/BMI AROUND 16Z AND THEN CMI AROUND 17Z. PCPN WILL
BE MAINLY SHOWERS BUT THUNDERSTORM ARE EMBEDDED IN THE COMPLEX SO
WILL ALSO HAVE A 2HR TEMPO GROUP FOR THUNDER AT EACH SITE DURING
THE LATE MORNING TO EARLY AFTERNOON. PCPN COULD LINGER BEHIND THE
MAIN AREA SO WILL BE KEEPING SHRA AND VCTS AT EACH SITE FOR COUPLE
HOURS AFTER TEMPO GROUP. ON BACK SIDE OF PCPN WINDS SHOULD ALSO
INCREASE SO WILL KEEP GUSTY WINDS DURING AFTERNOON. WINDS WILL BE
SOUTHERLY THROUGH THE PERIOD. CLOUDS WILL SCATTER OUT COUPLE OF
HOURS BEHIND THE SYSTEM AND THEN MOSTLY CLEAR AROUND SUNSET FOR
THE EVENING. NAM TRYING TO BRING SOME SC INTO THE AREA OVERNIGHT.
HOWEVER...UNSURE OF THIS SOLUTION SO WILL KEEP CLEAR FORECAST FOR
THE NIGHT HOURS FOR NOW.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 310 AM CDT TUE OCT 23 2012
WARM FRONT CURRENTLY LOCATED OVER NORTHERN ILLINOIS...ROUGHLY
ALONG THE I-80 CORRIDOR. HAVE BEEN SEEING SHOWERS AND STORMS
INCREASING ACROSS WESTERN ILLINOIS AND ESPECIALLY OVER
MISSOURI...AS AN UPPER WAVE MOVES INTO THE AREA AND AN APPARENT
MESOSCALE VORTEX TRACKS ACROSS MISSOURI PER WATER VAPOR IMAGERY.
INITIAL FORECAST CONCERN INVOLVES CONVECTIVE TRENDS FOR PRIMARILY
THIS MORNING...ALONG WITH ITS EFFECTS ON TEMPERATURES. IN THE
LONGER RANGE...THE TIMING OF A STRONG COLD FRONT ON THURSDAY
REMAINS AN ISSUE...ALONG WITH RAIN TRENDS THURSDAY AND FRIDAY.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST HRRR DOING A REASONABLE JOB WITH THE CONVECTION OVER
MISSOURI...AND IT CONTINUES TO INCREASE THE RAIN OVER MOST OF THE
CWA THROUGH EARLY MORNING. AS SUCH...HAVE RAMPED UP RAIN CHANCES
TO THE LIKELY RANGE IN MOST AREAS...PRIMARILY ALONG AND EAST OF
I-55. ANY LINGERING RAIN SHOULD BE TAPERING OFF EARLY IN THE
AFTERNOON. THE CONVECTION YESTERDAY REALLY THREW OFF THE HIGH
TEMPERATURE FORECAST...AND WILL HAVE TO KEEP THAT POTENTIAL IN
MIND FOR TODAY...ESPECIALLY IF CLOUDS ARE SLOW TO MOVE OUT. HAVE
LOWERED HIGHS FOR TODAY BY A FEW DEGREES IN MOST AREAS...CLOSER TO
A MET/MAV BLEND. HOWEVER...HAVE KEPT HIGHS NEAR 80 DEGREES ON
WEDNESDAY AND OVER THE EASTERN 2/3 OF THE CWA ON THURSDAY AS WELL.
UPPER WAVE CURRENTLY OVER THE PACIFIC NORTHWEST IS EXPECTED TO
FORM A CLOSED LOW AS IT MOVES NORTHEAST TO THE CANADIAN PRAIRIES
BY EARLY WEDNESDAY. 50-70 KNOT JET AT 500 MB WILL FOLLOW A WAVE
SLIDING ALONG THE SOUTHERN JET STREAM TO FEED INTO THE AREA AHEAD
OF THE COLD FRONT. LATEST MODEL GUIDANCE BRINGS THE FRONT INTO THE
NORTHWESTERN CWA THURSDAY AFTERNOON...AND ENTERING THE SOUTHEAST
CWA TOWARD MIDNIGHT. A NARROW WINDOW OF OPPORTUNITY EXISTS FOR
SOME STRONGER STORMS AHEAD OF THE FRONT THURSDAY AFTERNOON...
ALTHOUGH RAPIDLY INCREASING CLOUDS MAY THWART THIS POTENTIAL.
HOWEVER...THE RAIN WILL BE ON THE INCREASE...AND HAVE INTRODUCED
LIKELY POPS NORTHWEST OF THE ILLINOIS RIVER DURING THE AFTERNOON.
WITH THE BULK OF THE RAIN BEHIND THE FRONT...WILL SPREAD THE
LIKELY POPS FROM WEST TO EAST...WITH THE RAIN DIMINISHING WEST OF
I-55 AFTER MIDNIGHT.
LONG TERM...FRIDAY THROUGH MONDAY...
MODELS HAVE BEEN BACKING OFF ON THE IDEA OF A SECONDARY WAVE
FEEDING THE AREA BEHIND THE FRONT...WITH THE 00Z ECMWF THE ONLY
ONE STILL WITH THIS GENERAL TREND. WILL DROP THE RAIN CHANCES
NORTHWEST OF THE ILLINOIS RIVER ON FRIDAY AND FRIDAY NIGHT...AND
LOWER THEM QUITE A BIT FURTHER EAST. HOWEVER...THE GFS AND
CANADIAN MODELS WOULD SUGGEST COMPLETELY DRY CONDITIONS BY EARLY
FRIDAY EVENING EVERYWHERE...SO WILL NEED TO SEE IF THIS TREND
CONTINUES. HAVE REMOVED THE RAIN ON SATURDAY ASIDE FROM SOME
SLIGHT CHANCES EAST OF I-57...MAINLY DURING THE MORNING.
WEEKEND TREND STILL LOOKS QUITE CHILLY...WITH HIGHS IN MANY AREAS
STRUGGLING TO REACH THE 50 DEGREE MARK. SUB-FREEZING LOWS ARE
EXPECTED ALONG AND WEST OF I-55 BY SUNDAY MORNING. BEYOND
THAT...THE FORECAST TRENDS BECOME COMPLICATED BY A TROPICAL SYSTEM
MOVING NORTHWARD OFF THE EAST COAST. ECMWF MODEL IS MORE AFFECTED
AND FORMS A CUTOFF LOW OVER THE GREAT LAKES...LINGERING THE CHILLY
WEATHER INTO EARLY NEXT WEEK...WHEREAS THE GFS IS MORE PROGRESSIVE
AND MILDER. NEITHER SOLUTION CURRENTLY YIELDS ANY PRECIPITATION
FOR OUR AREA SUNDAY AND MONDAY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
944 AM CDT TUE OCT 23 2012
.DISCUSSION...
858 AM CDT
UPDATED GRIDS AND ZFP HAVE BEEN SENT WITH SIGNIFICANT CHANGES TO
FIRST PERIOD.
MORNING WATER VAPOR IMAGERY SHOWS A WELL DEFINED SHORTWAVE TROUGH
MOVING EASTWARD OVER IA/MO. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS LIKELY TO CONTINUE TO PERCOLATE IN THE VERY MOIST
AIRMASS OUT AHEAD OF THIS SHORTWAVE. MAJORITY OF THE ASCENT WITH
THIS WAVE SHOULD BE EAST OF THE CWA BY LATE AFTERNOON WITH SHOWER
AND THUNDERSTORM COVERAGE EXPECTED TO DECREASE TOWARD EVENING.
HAVE BUMPED UP SKY COVER CONSIDERABLY TODAY WITH NO HOPE OF SEEING
ANY BREAKS IN THE OVERCAST UNTIL THIS SHORTWAVE PASSES EAST OF THE
AREA LATE THIS AFTERNOON. EVEN THEN ONCE THE MID/HIGH LEVEL
MOISTURE CLEARS OUT THINKING ITS VERY LIKELY STRATUS DECK WILL
STICK AROUND AS OUR LATE OCTOBER SUN ANGLE IS ROUGHLY THE SAME AS
EARLY FEBRUARY AND WITH SUCH LATE CLEARING OF HIGH CLOUDS AND VERY
MOIST LOW LEVELS THINK IT WILL BE TOO LITTLE TOO LATE FOR THE SUN
TO EAT AWAY AT THE STRATUS. IN FACT...THERE IS A VERY REAL CHANCE
THAT STRATUS COULD STICK AROUND TONIGHT INTO TOMORROW MORNING AS
WELL AND HAVE BUMPED UP SKY GRIDS SOME TONIGHT. AFTERNOON FORECAST
MAY NEED TO CONSIDER ADJUSTING SKY COVER UP FURTHER TONIGHT INTO
TOMORROW.
GIVEN THE ANTICIPATED THICK OVERCAST MOST OF TODAY HAVE TAKEN A
HATCHET TO THE GOING HIGH TEMPERATURE FORECAST. GENERALLY WOULD
EXPECT TEMPS TO REMAIN NEARLY STEADY MOST OF THE DAY IN THE LOW TO
MID 60S...WITH A COUPLE/FEW DEGREE TEMP RISE POSSIBLE LATE THIS
AFTERNOON...ESPECIALLY FAR WESTERN CWA WHICH COULD POSSIBLY MAKE
A RUN AT 70 DEGREES STILL.
IZZI
//PREV DISCUSSION...
326 AM CDT
EARLY THIS MORNING THE FRONTAL BOUNDARY HAS STALLED ACROSS THE IL/WI
STATELINE. TO THE NORTH OF THE BOUNDARY TEMPS HAVE HELD IN THE
MID/UPR 50S WITH DEW PTS IN THE LOW/MID 50S WITH AREAS OF DENSE FOG.
SOUTH OF THE BOUNDARY TEMPS HAVE REMAINED VERY MILD FOR MID OCTOBER
IN THE 60S...ALONG WITH ANOMALOUSLY HIGH DEW PTS OF AROUND 60. IR
IMAGERY EARLY THIS MORNING DEPICTED THE LEADING EDGE OF HIGH BASED
CLOUDS FLOATING NORTH ALONG A CENTRAL IOWA...NORTHERN IL...TO FAR
SOUTHWEST LOWER MICHIGAN LINE. THIS AREA OF HIGH CLOUDS AND VERY
MOIST AIRMASS WAS ASSOCIATED WITH AN ELEVATED SHORTWAVE LIFTING
NORTHEAST ACROSS SOUTHWEST MISSOURI. SHOWERS AND THUNDERSTORMS HAVE
BEEN STEADILY GROWING IN COVERAGE ACROSS MISSOURI...AND BASED ON
CURRENT TRAJECTORIES THE LEADING PRECIP SHOULD ARRIVE ALONG THE
SOUTHWEST CWFA AROUND DAYBREAK. THEN STEADILY LIFT NORTHEAST ACROSS
THE REMAINING CWFA BY MID-MORNING. CURRENT GUIDANCE INDICATES CAPE
OF AROUND 500-750J/KG IN THE 15-18 TIMEFRAME...WHICH APPEARS TO BE
THE HIGHEST CONFIDENCE TIMING FOR CONVECTION TO OCCUR. SO HAVE
CARRIED LIKELY SHRA/TSRA AT THAT TIME.
AS THE ELEVATED WAVE ARRIVES ACROSS THE CWFA THIS MORNING...IT WILL
REMAIN PROGRESSIVE AND ALLOW PRECIP TO DIMINISH IN COVERAGE FROM
SOUTH TO NORTH ACROSS THE CWFA THIS AFTN. SUPPORTING THIS DRYING
TREND WILL BE THE SLOW RISE IN HEIGHTS ALOFT...INDICATING WEAK
DIFFLUENCE ALOFT.
WITH REGARDS TO TEMPS TODAY...GUIDANCE IS DEMONSTRATING A HIGHER
CONFIDENCE THAT TEMPS WILL EASILY WARM INTO THE 70S. THE CHALLENGE
IS DETERMINE THE LOCATIONS THAT WILL WARM INTO THE MID 70S...WHICH
CURRENTLY APPEARS TO BE ALONG AND SOUTH OF A ROCKFORD TO KANKAKEE
LINE. THE OTHER WILDCARD FOR LOCATIONS NORTH OF THIS LINE WILL BE
THE CLOUD COVER AND LINGERING PRECIP. AT THIS TIME IT APPEARS BY 21Z
ALL BUT A FEW SHRA SHOULD HAVE DEPARTED THE CWFA TO THE
NORTH...ALTHOUGH CLOUDS MAY STILL BE MOSTLY CLOUDY. PWAT VALUES WILL
REMAIN ABOVE 1 INCH THRU THE DAY TDY...WITH A HANDFUL OF LOCATIONS
RISING TO NEARLY 1.5 INCHES. THE COMBINATION OF MILD TEMPS AND HIGH
MOISTURE CONTENT IN THE ATMOSPHERE WILL MAKE TODAY AND WED FEEL MORE
LIKE SUMMER.
SOUTHERLY FLOW WILL LINGER THROUGH THE OVERNIGHT...AND SHOULD BE
JUST STRONG ENOUGH TO PREVENT DENSE FG FROM FORMING. THUS WILL ONLY
MENTION PATCHY FG IN THE FORECAST TONIGHT. ANOTHER MILD NIGHT
APPEARS LIKELY FOR TONIGHT WITH TEMPS ONLY COOLING INTO THE LOW 60S.
A FEW GUIDANCE MEMBERS WERE WARMER THAN THIS IN THE MID 60S AT A
HANDFUL OF POINTS...HOWEVER FELT THE GENERAL CONSENSUS WOULD BE
AROUND 60 TO PSBLY LOW 60S. DRY WEATHER SHOULD LAST THROUGH THE
OVERNIGHT HOURS AS WELL.
WEDNESDAY THROUGH THURSDAY...
500MB RIDGE PUSHES OVERHEAD WITH WEAK DIFFLUENT FLOW IN THE
LLVLS...SUGGESTING MUCH OF WED THRU AT LEAST DAYBREAK THUR WILL
REMAIN DRY. FOR WED THIS WILL SET THE STAGE FOR A RUN AT TEMPS
AROUND 80...PSBLY WARMING INTO THE LOW 80S FOR A FEW LOCATIONS WED
AFTN. THE DEEPER MOISTURE WILL PEEL OFF TO THE NORTHEAST WITH THE
WARM FRONTAL BOUNDARY...WHICH MAY AID IN SLIGHTLY LOWER DEW PTS AND
PWAT VALUES HOVER AROUND 1 INCH WED AFTN. IF DEW PTS CAN FALL INTO
THE MID/UPR 50S...THIS WOULD ALLOW THE SFC TO WARM MORE EFFICIENTLY
AND ALLOW THE SFC TO EASILY REACH 80 DEG IN MANY LOCATIONS OF THE
CWFA. CURRENT TEMP PLUMES FROM THE SREF AND VARIOUS OTHER GUIDANCE
SOURCES...INDICATE TEMPS WED WILL BE IN THE MID/UPR 70S OVER THE FAR
NORTHERN TIER OF COUNTIES IN IL. MEANWHILE FURTHER SOUTH OR SOUTH OF
I-88...TEMPS COULD WARM INTO THE UPR 70S TO AROUND 80. CLOUDS WILL
ALSO PLAY A ROLE...HOWEVER CURRENTLY FORECASTING P-CLOUDY CONDS WED.
THEN FOR THUR AHEAD OF THE FRONTAL BNDRY...TEMPS COULD WARM AGAIN
INTO THE MID/UPR 70S MAINLY FOR FAR EASTERN SECTIONS OF THE CWFA.
500MB TROUGH AXIS WILL BEGIN TO PUSH INTO THE CENTRAL PLAINS WED
NGT/EARLY THUR...WITH THE MAIN VORT MAX ROUNDING THE TROUGH AXIS
EARLY THUR MORNING ACROSS THE SOUTHERN PLAINS. IT APPEARS THAT THE
DOWNSTREAM RIDGE WILL EXTEND FROM QUEBEC TO THE CAROLINAS...WHICH
MAY ALLOW THE FRONTAL BNDRY TO SLOW SLIGHTLY. IF THE BNDRY SLOWS
FURTHER...PRECIP COULD REMAIN WEST OF THE CWFA THRU THE EARLY AFTN
HOURS AND ALLOW TEMPS TO BE EVEN WARMER...GIVEN THE POTENTIAL FOR
COMPRESSIONAL HEATING TO OCCUR BETWEEN THE DEPARTING SFC RIDGE AND
UPSTREAM TROUGH.
INSTABILITY WILL DEVELOP WITH THE PASSAGE THUR AFTN...THEN SHUD
STABILIZE IN THE EVENING HOURS WITH FRONTAL PASSAGE. WINDS WILL TURN
NW...WITH MUCH COOLER AIR STEADILY ADVECTING ACROSS THE CWFA.
THERMAL RIDGE OF 15 TO 17 DEG C AT 850MB RAPIDLY TRANSITIONS TO
AROUND 5 DEG C BY 06Z FRI.
FRIDAY THROUGH MONDAY...
POTENT ANTI-CYCLONIC FLOW QUICKLY ARRIVES FRI...AND SHUD PUSH THE
PRECIP/CLOUDS TO THE EAST ACROSS IN/MI. HOWEVER A FEW EASTERN AREAS
COULD CONTINUE TO SEE A SLIGHT CHC POPS FRI. FRI APPEARS TO BE THE
WARMEST DAY IN THE FINAL PERIODS OF THE EXTENDED...WITH TEMPS
EXPECTED TO BE IN THE LOW 50S. THESE HIGH TEMPS MAY ACTUALLY ARRIVE
EARLY IN THE DAY...AS COLD AIR CONTINUES TO POUR IN FROM THE
NORTHWEST THROUGHOUT THE DAY.
LAKE EFFECT CONDS DEVELOP AND BECOME OPTIMAL FRI NGT/SAT/SAT NGT FOR
THE FAVORED AREAS OF NORTHWEST IN. THERMAL TROUGH OVERHEAD WILL
CONTINUE TO COOL WITH 0 TO -3 DEG C AT 850MB POISED TO PUSH OVERHEAD
SAT/SUN. THUS IT APPEARS TEMPS WILL STRUGGLE TO WARM BEYOND THE
LOW/MID 40S. AT THIS TIME IT DOES NOT APPEAR CLOUDS WILL BE A MAJOR
PLAYER. IN ADDITION DRY WEATHER SHOULD REMAIN THRU THE BULK OF THE
EXTENDED...WITH THE EXCEPTION OF NORTHWEST IN. ANY LINGERING PRECIP
DURING THE NOCTURNAL HOURS FRI/SAT/SUN COULD BECOME MIXED WITH SOME
WET SNOW...AS TEMPS WILL BE COOLING INTO THE MID 30S EACH OF THESE
NIGHTS. SAT NGT COULD BE THE COOLEST DAY AS GUIDANCE HAS INDICATED
THE SFC RIDGE PUSHING OVER CENTRAL WI. THIS COULD ALLOW WINDS TO
DIMINISH AND CLOUDS TO REMAIN MINIMAL...ALLOWING FOR OPTIMAL
RADIATIONAL COOLING TO TAKE PLAY SAT NGT. IF THIS SCENARIO WERE TO
VERIFY...TEMPS COULD EASILY BOTTOMOUT IN THE UPR 20S ACROSS THE
CWFA.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LIFR/IFR REST OF MORNING INTO EARLY AFTERNOON.
* WIND GRADUALLY VEERING FROM E TO S LATE MORNING THROUGH EARLY
AFTERNOON.
* PERIODS OF -RA WITH LOCAL SHRA REST OF MORNING THROUGH EARLY
AFTERNOON.
TRS
//DISCUSSION...UPDATED 14Z...
TROUGH/WARM FRONT HAS NOT LIFTED NWRD AS SOON AS MODELS EARLIER
INDICATED AND EVEN LATEST AVAILABLE HI RES HRRR AND RAP PLACE IT
TOO FAR N NEAR/TO WI BORDER BY 15-16Z WHICH LOOKS TO BE A COUPLE
HRS TOO FAST. LIFR AND IFR EXPECTED TO PERSIST TIL BOUNDARY DOES
LIFT N PAST TERMINALS AND WINDS BECOME SRLY BTWN 17Z-19Z THEN
CIGS SHUD LIFT AND VSBYS IMPROVE.
BETWEEN AREA OF RA AND TS MOVING ENE OVER NRN IN AND ANOTHER AREA
OF MAINLY RA AND A FEW TS MOVING SLIGHTLY N OF E FM ERN MO ACROSS
THE MS RIVER ARE SCT DISORGANIZED -SHRA AND ISOLD SHRA. MODELS
SHOW BULK OF QPF E OF LOCAL TERMINALS BY 18Z AS UPPER TROUGH FROM
NRN MO SSE TO NERN AR MOVES OVER AND PAST THE LOCAL AREA. MODELS
DO INDICATE SPOTTY QPF 18Z-00Z BUT AMOUNTS OF ONLY A COUPLE
HUNDREDTHS OF AN INCH. DO NOT SEE ANY SIGNIFICANT FORCING
MECHANISMS FOR ADDITIONAL SHRA GENERATION BEYOND EARLY AFTERNOON.
TRS
PREVIOUS DISCUSSION...UPDATED 12Z...
TWO MAIN CONCERNS/CHALLENGES...CIGS AND TSRA THIS MORNING. LIFR
CIGS HAVE REMAINED LOCKED IN AND WITH CONTINUED LIGHT NORTHEAST
WINDS OFF THE LAKE...EXPECT AT LEAST A FEW MORE HOURS OF LIFR CIGS
UNTIL WINDS START TO TURN MORE SOUTHERLY AND CIGS LIFT. CONFIDENCE
REGARDING TIMING REMAINS LOW. ONCE CIGS DO LIFT...MVFR CIGS LIKELY
TO CONTINUE INTO THE EARLY/MID AFTERNOON.
ONE COMPLEX OF TSRA OVER EASTERN IL/WESTERN INDIANA WILL REMAIN
SOUTH OF THE TERMINALS WHILE CONVECTION OVER MISSOURI HAS WEAKENED
CONSIDERABLY IN THE PAST FEW HOURS. SHORT TERM GUIDANCE STILL
SUGGESTS FURTHER SHRA DEVELOPMENT ACROSS WESTERN IL THIS MORNING
BUT CONFIDENCE REGARDING TSRA POTENTIAL IS DECREASING AND TRENDS
WILL NEED TO BE MONITORED FOR POSSIBLE UPDATES.
SOUTHERLY WINDS MAY GUST INTO THE MID TEENS THIS AFTERNOON BUT
THIS WILL BE DEPENDENT ON SUNSHINE AND LOW LEVEL MIXING WHICH MAY
NOT OCCUR. SOUTHERLY WINDS WILL PERSIST TONIGHT AND SHOULD BEGIN
TO GUST SOME WEDNESDAY MORNING. WITH THE WARM FRONT EXPECTED TO BE
WELL NORTH OF THE AREA TONIGHT...NOT EXPECTING ANY WIDESPREAD FOG
OR LOW CIG PROBLEMS BUT HAVE INCLUDED SOME MVFR VIS AT RFD/DPA.
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE LIFR AND IFR CIGS WILL LIFT TO MVFR LATE
MORNING-EARLY AFTERNOON AND TO VFR EARLY-MID AFTERNOON.
* MEDIUM CONFIDENCE SCT -SHRA/ISOLD SHRA REST OF MORNING INTO
EARLY AFTERNOON.
* MEDIUM CONFIDENCE IN TIMING OF WINDS VEERING FM E TO S.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT...VFR.
* THURSDAY...STRONG/GUSTY SOUTHWEST WINDS. SHRA/TSRA THURSDAY
AFTERNOON/EARLY EVENING...ALONG/AHEAD OF WIND SHIFT/COLD FRONT.
* FRIDAY AND SATURDAY...SLIGHT CHANCE OF SHRA.
* SUNDAY AND MONDAY...VFR.
&&
.MARINE...
308 AM...A FRONTAL BOUNDARY HAS BECOME NEARLY STATIONARY JUST
SOUTH OF LAKE MICHIGAN EARLY THIS MORNING. IT WILL BEGIN TO SLOWLY
LIFT NORTH LATER TODAY AND TONIGHT AS LOW PRESSURE OVER THE
NORTHERN PLAINS LIFTS NORTH INTO SOUTHERN CANADA. HOWEVER...WITH
HIGH PRESSURE ACROSS ONTARIO...THE GRADIENT WILL REMAIN FAIRLY
STRONG ACROSS THE NORTHERN THIRD OR QUARTER OF THE LAKE WITH
EASTERLY WINDS 15-25 KTS INTO TONIGHT...SLOWLY TURNING SOUTHEAST
AND WEAKENING BY WEDNESDAY MORNING. NEW LOW PRESSURE WILL DEVELOP
OVER EASTERN COLORADO TONIGHT AND MOVE NORTHEAST TO NEAR LAKE
SUPERIOR BY THURSDAY AFTERNOON. THE GRADIENT WILL STEADILY TIGHTEN
AHEAD OF THIS FRONT WEDNESDAY NIGHT INTO THURSDAY MORNING BUT
FORECAST SOUNDINGS SHOW A FAIRLY STRONG MARINE LAYER/INVERSION.
BUT WINDS STILL EXPECTED TO REACH 30 KTS OR SO. WINDS WILL
DIMINISH AHEAD OF THE COLD FRONT LATE THURSDAY AFTERNOON/EARLY
THURSDAY EVENING THEN SHIFT OUT OF THE NORTHWEST BEHIND THE FRONT.
WITH HIGH PRESSURE BUILDING ACROSS THE PLAINS...THE GRADIENT
BEHIND THE FRONT WILL LIKELY SUPPORT GUSTS TO 30 KTS. COULD BE AN
HOUR OR TWO OF HIGHER GUSTS WITH/JUST BEHIND THE FRONT.
LIGHT WINDS ACROSS THE SOUTHERN TWO THIRDS OF THE LAKE...COMBINED
WITH THE VERY MOIST LOW LEVELS WILL LIKELY LEAD TO AREAS OF FOG
AND MAYBE SOME PATCHY DENSE FOG...THIS MORNING WHICH SHOULD
IMPROVE AS WINDS TURN MORE SOUTHERLY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
648 AM CDT TUE OCT 23 2012
.DISCUSSION...
ISSUED 310 AM CDT TUE OCT 23 2012
WARM FRONT CURRENTLY LOCATED OVER NORTHERN ILLINOIS...ROUGHLY
ALONG THE I-80 CORRIDOR. HAVE BEEN SEEING SHOWERS AND STORMS
INCREASING ACROSS WESTERN ILLINOIS AND ESPECIALLY OVER
MISSOURI...AS AN UPPER WAVE MOVES INTO THE AREA AND AN APPARENT
MESOSCALE VORTEX TRACKS ACROSS MISSOURI PER WATER VAPOR IMAGERY.
INITIAL FORECAST CONCERN INVOLVES CONVECTIVE TRENDS FOR PRIMARILY
THIS MORNING...ALONG WITH ITS EFFECTS ON TEMPERATURES. IN THE
LONGER RANGE...THE TIMING OF A STRONG COLD FRONT ON THURSDAY
REMAINS AN ISSUE...ALONG WITH RAIN TRENDS THURSDAY AND FRIDAY.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST HRRR DOING A REASONABLE JOB WITH THE CONVECTION OVER
MISSOURI...AND IT CONTINUES TO INCREASE THE RAIN OVER MOST OF THE
CWA THROUGH EARLY MORNING. AS SUCH...HAVE RAMPED UP RAIN CHANCES
TO THE LIKELY RANGE IN MOST AREAS...PRIMARILY ALONG AND EAST OF
I-55. ANY LINGERING RAIN SHOULD BE TAPERING OFF EARLY IN THE
AFTERNOON. THE CONVECTION YESTERDAY REALLY THREW OFF THE HIGH
TEMPERATURE FORECAST...AND WILL HAVE TO KEEP THAT POTENTIAL IN
MIND FOR TODAY...ESPECIALLY IF CLOUDS ARE SLOW TO MOVE OUT. HAVE
LOWERED HIGHS FOR TODAY BY A FEW DEGREES IN MOST AREAS...CLOSER TO
A MET/MAV BLEND. HOWEVER...HAVE KEPT HIGHS NEAR 80 DEGREES ON
WEDNESDAY AND OVER THE EASTERN 2/3 OF THE CWA ON THURSDAY AS WELL.
UPPER WAVE CURRENTLY OVER THE PACIFIC NORTHWEST IS EXPECTED TO
FORM A CLOSED LOW AS IT MOVES NORTHEAST TO THE CANADIAN PRAIRIES
BY EARLY WEDNESDAY. 50-70 KNOT JET AT 500 MB WILL FOLLOW A WAVE
SLIDING ALONG THE SOUTHERN JET STREAM TO FEED INTO THE AREA AHEAD
OF THE COLD FRONT. LATEST MODEL GUIDANCE BRINGS THE FRONT INTO THE
NORTHWESTERN CWA THURSDAY AFTERNOON...AND ENTERING THE SOUTHEAST
CWA TOWARD MIDNIGHT. A NARROW WINDOW OF OPPORTUNITY EXISTS FOR
SOME STRONGER STORMS AHEAD OF THE FRONT THURSDAY AFTERNOON...
ALTHOUGH RAPIDLY INCREASING CLOUDS MAY THWART THIS POTENTIAL.
HOWEVER...THE RAIN WILL BE ON THE INCREASE...AND HAVE INTRODUCED
LIKELY POPS NORTHWEST OF THE ILLINOIS RIVER DURING THE AFTERNOON.
WITH THE BULK OF THE RAIN BEHIND THE FRONT...WILL SPREAD THE
LIKELY POPS FROM WEST TO EAST...WITH THE RAIN DIMINISHING WEST OF
I-55 AFTER MIDNIGHT.
LONG TERM...FRIDAY THROUGH MONDAY...
MODELS HAVE BEEN BACKING OFF ON THE IDEA OF A SECONDARY WAVE
FEEDING THE AREA BEHIND THE FRONT...WITH THE 00Z ECMWF THE ONLY
ONE STILL WITH THIS GENERAL TREND. WILL DROP THE RAIN CHANCES
NORTHWEST OF THE ILLINOIS RIVER ON FRIDAY AND FRIDAY NIGHT...AND
LOWER THEM QUITE A BIT FURTHER EAST. HOWEVER...THE GFS AND
CANADIAN MODELS WOULD SUGGEST COMPLETELY DRY CONDITIONS BY EARLY
FRIDAY EVENING EVERYWHERE...SO WILL NEED TO SEE IF THIS TREND
CONTINUES. HAVE REMOVED THE RAIN ON SATURDAY ASIDE FROM SOME
SLIGHT CHANCES EAST OF I-57...MAINLY DURING THE MORNING.
WEEKEND TREND STILL LOOKS QUITE CHILLY...WITH HIGHS IN MANY AREAS
STRUGGLING TO REACH THE 50 DEGREE MARK. SUB-FREEZING LOWS ARE
EXPECTED ALONG AND WEST OF I-55 BY SUNDAY MORNING. BEYOND
THAT...THE FORECAST TRENDS BECOME COMPLICATED BY A TROPICAL SYSTEM
MOVING NORTHWARD OFF THE EAST COAST. ECMWF MODEL IS MORE AFFECTED
AND FORMS A CUTOFF LOW OVER THE GREAT LAKES...LINGERING THE CHILLY
WEATHER INTO EARLY NEXT WEEK...WHEREAS THE GFS IS MORE PROGRESSIVE
AND MILDER. NEITHER SOLUTION CURRENTLY YIELDS ANY PRECIPITATION
FOR OUR AREA SUNDAY AND MONDAY.
GEELHART
&&
.AVIATION...
ISSUED 648 AM CDT TUE OCT 23 2012
WILL BE A BREAK IN THE PCPN THIS MORNING AS AREA WILL BE IN
BETWEEN COMPLEXES. THE NEXT ROUND OF PCPN SHOULD REACH SPI/PIA
AROUND 15Z...DEC/BMI AROUND 16Z AND THEN CMI AROUND 17Z. PCPN WILL
BE MAINLY SHOWERS BUT THUNDERSTORM ARE EMBEDDED IN THE COMPLEX SO
WILL ALSO HAVE A 2HR TEMPO GROUP FOR THUNDER AT EACH SITE DURING
THE LATE MORNING TO EARLY AFTERNOON. PCPN COULD LINGER BEHIND THE
MAIN AREA SO WILL BE KEEPING SHRA AND VCTS AT EACH SITE FOR COUPLE
HOURS AFTER TEMPO GROUP. ON BACK SIDE OF PCPN WINDS SHOULD ALSO
INCREASE SO WILL KEEP GUSTY WINDS DURING AFTERNOON. WINDS WILL BE
SOUTHERLY THROUGH THE PERIOD. CLOUDS WILL SCATTER OUT COUPLE OF
HOURS BEHIND THE SYSTEM AND THEN MOSTLY CLEAR AROUND SUNSET FOR
THE EVENING. NAM TRYING TO BRING SOME SC INTO THE AREA OVERNIGHT.
HOWEVER...UNSURE OF THIS SOLUTION SO WILL KEEP CLEAR FORECAST FOR
THE NIGHT HOURS FOR NOW.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
310 AM CDT TUE OCT 23 2012
.DISCUSSION...
ISSUED 310 AM CDT TUE OCT 23 2012
WARM FRONT CURRENTLY LOCATED OVER NORTHERN ILLINOIS...ROUGHLY
ALONG THE I-80 CORRIDOR. HAVE BEEN SEEING SHOWERS AND STORMS
INCREASING ACROSS WESTERN ILLINOIS AND ESPECIALLY OVER
MISSOURI...AS AN UPPER WAVE MOVES INTO THE AREA AND AN APPARENT
MESOSCALE VORTEX TRACKS ACROSS MISSOURI PER WATER VAPOR IMAGERY.
INITIAL FORECAST CONCERN INVOLVES CONVECTIVE TRENDS FOR PRIMARILY
THIS MORNING...ALONG WITH ITS EFFECTS ON TEMPERATURES. IN THE
LONGER RANGE...THE TIMING OF A STRONG COLD FRONT ON THURSDAY
REMAINS AN ISSUE...ALONG WITH RAIN TRENDS THURSDAY AND FRIDAY.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST HRRR DOING A REASONABLE JOB WITH THE CONVECTION OVER
MISSOURI...AND IT CONTINUES TO INCREASE THE RAIN OVER MOST OF THE
CWA THROUGH EARLY MORNING. AS SUCH...HAVE RAMPED UP RAIN CHANCES
TO THE LIKELY RANGE IN MOST AREAS...PRIMARILY ALONG AND EAST OF
I-55. ANY LINGERING RAIN SHOULD BE TAPERING OFF EARLY IN THE
AFTERNOON. THE CONVECTION YESTERDAY REALLY THREW OFF THE HIGH
TEMPERATURE FORECAST...AND WILL HAVE TO KEEP THAT POTENTIAL IN
MIND FOR TODAY...ESPECIALLY IF CLOUDS ARE SLOW TO MOVE OUT. HAVE
LOWERED HIGHS FOR TODAY BY A FEW DEGREES IN MOST AREAS...CLOSER TO
A MET/MAV BLEND. HOWEVER...HAVE KEPT HIGHS NEAR 80 DEGREES ON
WEDNESDAY AND OVER THE EASTERN 2/3 OF THE CWA ON THURSDAY AS WELL.
UPPER WAVE CURRENTLY OVER THE PACIFIC NORTHWEST IS EXPECTED TO
FORM A CLOSED LOW AS IT MOVES NORTHEAST TO THE CANADIAN PRAIRIES
BY EARLY WEDNESDAY. 50-70 KNOT JET AT 500 MB WILL FOLLOW A WAVE
SLIDING ALONG THE SOUTHERN JET STREAM TO FEED INTO THE AREA AHEAD
OF THE COLD FRONT. LATEST MODEL GUIDANCE BRINGS THE FRONT INTO THE
NORTHWESTERN CWA THURSDAY AFTERNOON...AND ENTERING THE SOUTHEAST
CWA TOWARD MIDNIGHT. A NARROW WINDOW OF OPPORTUNITY EXISTS FOR
SOME STRONGER STORMS AHEAD OF THE FRONT THURSDAY AFTERNOON...
ALTHOUGH RAPIDLY INCREASING CLOUDS MAY THWART THIS POTENTIAL.
HOWEVER...THE RAIN WILL BE ON THE INCREASE...AND HAVE INTRODUCED
LIKELY POPS NORTHWEST OF THE ILLINOIS RIVER DURING THE AFTERNOON.
WITH THE BULK OF THE RAIN BEHIND THE FRONT...WILL SPREAD THE
LIKELY POPS FROM WEST TO EAST...WITH THE RAIN DIMINISHING WEST OF
I-55 AFTER MIDNIGHT.
LONG TERM...FRIDAY THROUGH MONDAY...
MODELS HAVE BEEN BACKING OFF ON THE IDEA OF A SECONDARY WAVE
FEEDING THE AREA BEHIND THE FRONT...WITH THE 00Z ECMWF THE ONLY
ONE STILL WITH THIS GENERAL TREND. WILL DROP THE RAIN CHANCES
NORTHWEST OF THE ILLINOIS RIVER ON FRIDAY AND FRIDAY NIGHT...AND
LOWER THEM QUITE A BIT FURTHER EAST. HOWEVER...THE GFS AND
CANADIAN MODELS WOULD SUGGEST COMPLETELY DRY CONDITIONS BY EARLY
FRIDAY EVENING EVERYWHERE...SO WILL NEED TO SEE IF THIS TREND
CONTINUES. HAVE REMOVED THE RAIN ON SATURDAY ASIDE FROM SOME
SLIGHT CHANCES EAST OF I-57...MAINLY DURING THE MORNING.
WEEKEND TREND STILL LOOKS QUITE CHILLY...WITH HIGHS IN MANY AREAS
STRUGGLING TO REACH THE 50 DEGREE MARK. SUB-FREEZING LOWS ARE
EXPECTED ALONG AND WEST OF I-55 BY SUNDAY MORNING. BEYOND
THAT...THE FORECAST TRENDS BECOME COMPLICATED BY A TROPICAL SYSTEM
MOVING NORTHWARD OFF THE EAST COAST. ECMWF MODEL IS MORE AFFECTED
AND FORMS A CUTOFF LOW OVER THE GREAT LAKES...LINGERING THE CHILLY
WEATHER INTO EARLY NEXT WEEK...WHEREAS THE GFS IS MORE PROGRESSIVE
AND MILDER. NEITHER SOLUTION CURRENTLY YIELDS ANY PRECIPITATION
FOR OUR AREA SUNDAY AND MONDAY.
GEELHART
&&
.AVIATION...
ISSUED 1141 PM CDT MON OCT 22 2012
SHORT-WAVE TROUGH EVIDENT ON 04Z WATER VAPOR IMAGERY OVER EASTERN
KANSAS WILL LIFT NORTHEASTWARD...BRINGING ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO CENTRAL ILLINOIS LATE TONIGHT INTO TUESDAY
MORNING. 0430Z RADAR MOSAIC SHOWS SCATTERED SHOWERS ACROSS CENTRAL
MISSOURI...WITH A CLUSTER OF CONVECTION DEVELOPING ACROSS SOUTHWEST
MISSOURI. AS UPPER WAVE APPROACHES AND LOW-LEVEL JET INCREASES...THINK
SHOWERS/STORMS WILL BECOME MORE WIDESPREAD ACROSS MISSOURI OVER
THE NEXT COUPLE OF HOURS. THIS PRECIPITATION WILL THEN SPREAD
NORTHEASTWARD INTO CENTRAL ILLINOIS TOWARD DAWN. BASED ON THE 01Z
HRRR AND LATEST RADAR TRENDS...HAVE INTRODUCED PREDOMINANT SHOWERS
AT KSPI BY 08Z...THEN FURTHER NORTHEAST TO KBMI AND KCMI BY 10Z.
WILL CARRY SHOWERS FOR ABOUT 7 TO 8 HOURS AT EACH TERMINAL...ENDING
FROM WEST TO EAST TOWARD MIDDAY. TIMING OF INDIVIDUAL THUNDERSTORMS
AT EACH TAF SITE REMAINS DIFFICULT...SO WILL ONLY MENTION VCTS AT
THIS TIME. ONCE UPPER WAVE TRACKS OFF TO THE NORTHEAST...SHOWERS
WILL COME TO AN END AND SKIES WILL GRADUALLY CLEAR BY TUESDAY
AFTERNOON/EVENING. WINDS WILL INITIALLY BE FROM THE SOUTH AT
AROUND 10KT TONIGHT...THEN WILL INCREASE AND GUST TO AROUND 20KT
ONCE THE RAIN ENDS TUESDAY AFTERNOON.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
351 PM EDT TUE OCT 23 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
ONGOING PRECIP CHANCES THROUGH THIS EVENING AND CONTINUED MODERATING
TREND INTO WEDNESDAY WILL BE THE MAIN FORECAST ISSUES FOR THE SHORT
TERM.
CONVECTIVE COMPLEX AIDED BY MCV THIS MORNING HAS DIMINISHED...BUT
HAS LEFT SOME RESIDUAL COOL/STABLE LOW LEVELS. RAP INITIALIZATION
SOUNDINGS THIS AFTERNOON DO DEPICT SOME WEAK ELEVATED INSTABILITY
PERSISTING FOR 850 HPA BASED PARCELS HOWEVER. REMAINING SCATTERED
SHOWER ACTIVITY APPEARS TO BE FAIRLY WELL ALIGNED WITH WEAK DPVA
ZONE IN ADVANCE OF REMNANTS OF DAMPENING BAJA OF CALIFORNIA SHORT
WAVE. A STRONGER VORT MAX ASSOCIATED WITH THIS DECAYING TROUGH
APPEARS TO BE WORKING ACROSS SOUTHERN ILLINOIS THIS AFTERNOON AND
SHOULD REMAIN SOUTH OF FORECAST AREA. WILL CARRY SOME CHANCE POPS
LATE AFTERNOON INTO EARLY THIS EVENING IN ASSOCIATION WITH THE LEAD
SHORT WAVE...WITH PRECIP CHANCES DIMINISHING FROM WEST TO EAST THIS
EVENING. STILL CANNOT COMPLETELY RULE OUT AN ISOLD THUNDERSTORM
THROUGH 00Z GIVEN WEAK ELEVATED INSTABILITY AND PERIOD OF STRONGEST
FORCING WITH THIS SHORT WAVE. OTHERWISE...MILD CONDITIONS IN STORE
TONIGHT WITH LOCAL AREA REMAINING IN WARM SECTOR. SOME SCATTERING OF
LOW CLOUDS EXPECTED TONIGHT...AND RELATIVELY WEAK SFC GRADIENT
SHOULD ALLOW FOR MINS FROM THE MID TO UPPER 50S EAST...TO AROUND 60
FAR WEST. IF LOW CLOUDS DO SCATTER THIS EVENING...GRADIENT SHOULD
REMAIN WEAK ENOUGH FOR SOME PATCHY RADIATIONAL FOG TO DEVELOP BUT
STRENGTHENING LOW LEVEL HEIGHT GRADIENT LATE TONIGHT LENDS SOME LOW
CONFIDENCE IN THIS SCENARIO.
UNSEASONABLY WARM CONDITIONS IN STORE FOR TOMORROW AS REINFORCING
LOW LEVEL THERMAL RIDGE IN THE LEE OF THE ROCKIES ADVECTS NORTHEAST
INTO THE SOUTHERN GREAT LAKES. SOME LINGERING STRATUS IS POSSIBLE
MAINLY ACROSS FAR NORTH AND FAR EAST WEDNESDAY MORNING...BUT MOST
LOCATIONS SHOULD HAVE PLENTY OF AFTERNOON SUNSHINE. DESPITE LIMITED
MIXING HEIGHTS...MIXING TO 900 HPA SHOULD SUPPORT HIGHS IN THE UPPER
70S WHICH IS INLINE WITH PREVIOUS FORECAST. THE RECORD HIGH AT KSBN
FOR OCTOBER 24TH IS 79 SET BACK IN 1975 WHICH DOES APPEAR TO BE AT
RISK OF BEING REACHED. DRY...MILD CONDITIONS TO CONTINUE THROUGH
WEDNESDAY NIGHT AS AREA REMAINS IN WARM SECTOR. SOME DRIER LOW LEVEL
AIR WILL ADVECT NORTHWARD IN ADVANCE OF NEXT SIGNIFICANT UPPER
LEVEL TROUGH DIGGING ACROSS THE ROCKIES WHICH MAY TEND TO OFFSET THE
STRONGER GRADIENT WEDNESDAY NIGHT FOR LOWS SIMILAR TO THAT OF
TONIGHT.
&&
.LONG TERM.../THURSDAY THROUGH TUESDAY/
ENERGY FROM CLOSED LOW OFF THE WEST COAST WILL BEGIN TO TRANSLATE
EASTWARD WITH TIME AND BRING A CONTINUATION OF ACTIVE WEATHER AND
MUCH COOLER TEMPERATURES TO THE REGION.
THURSDAY THROUGH FRIDAY...
EFFECTS OF LARGE TROUGH DIGGING INTO THE PLAINS WILL FURTHER IMPACT
THE REGION WITH WARMEST AIR ARRIVING JUST AHEAD OF APPROACHING COLD
FRONT. MODEL SOUNDINGS SUGGEST MOSTLY SUNNY SKIES SHOULD ALLOW
MIXING THROUGH AT LEAST 900 MB AND POSSIBLY 850 MB YIELDING HIGHS
WELL INTO THE 70S WITH A FEW SPOTS RUNNING TOWARDS 80
POSSIBLE...ESPECIALLY SE. COLD FRONT WILL MOVE TOWARDS THE AREA BY
LATE AFTERNOON...INCREASING CLOUDS JUST AHEAD OF IT WITH EASTWARD
TREND EXPECTED IN TERMS OF MSTR THROUGH THURS NGT. MINOR DIFFERENCES
IN EXACT TIMING OF WIND SHIFT (GIVE OR TAKE A FEW HOURS) WITH ALL
MODELS GENERALLY AGREEING OF A SLOW PUSH AS WAVES MOVE ALONG THE
FRONT. AREA OF POST FRONTAL SHOWERS/STORMS ARE EXPECTED TO DEVELOP
TO THE WEST AND ENTER WESTERN AREAS DURING THE EVENING. COMBINATION
OF SOME DRY AIR ENTRAINMENT AND LESS OPTIMAL TIME FRAME FOR FROPA
MAY ALLOW FOR A DECREASE IN COVERAGE OF PRECIP INTO THE OVERNIGHT
HOURS. MODELS THEN REFIRE SHOWERS IN MAINLY EASTERN AREAS ON FRIDAY
AS MAIN ENERGY FINALLY DIGS IN AND PUSHES FRONT OUT OF THE AREA.
WITH INCREASED CLOUD COVER AND CAA UNDERWAY HIGHS ON FRIDAY WILL BE
A GOOD 15 TO 25 DEGREES COLDER THAN THURSDAY.
SATURDAY THROUGH TUESDAY...
CONFIDENCE IN FORECAST BEGINS TO WANE DURING THIS TIME FRAME WITH
MODEL CAMP GENERALLY SPLIT ON HANDLING ON INTERACTION BETWEEN
LONGWAVE TROUGH OVER THE GREAT LAKES AND TROPICAL CYCLONE SANDY OVER
THE WEEKEND INTO NEXT WEEK. INITIALLY...CONTINUED NW TO N FLOW OVER
THE LAKES WILL LIKELY KEEP LAKE EFFECT CLOUD COVER AND SOME CHANCES
FOR SHOWERS AROUND...POSSIBLY MIXED WITH SNOW. EXACT TRAJECTORIES
AND AMOUNT OF RESIDENT MSTR REMAIN IN QUESTION THIS FAR OUT.
GENERALLY WENT WITH COMBO OF PREV AND CONSALL TO HANDLE THIS TIME
FRAME.
RAN PRETTY MUCH WITH EITHER ALLBLEND OF GUIDANCE OR CONSALL FOR MANY
PARAMETERS INTO TUESDAY AS EXACT DETAILS OF EVOLUTION OF EAST COAST
SYSTEM REMAIN IN FLUX. ECMWF/GEM HAVE REMAINED CONSISTENT ON A
STRONG WESTWARD PULL OF THE TROPICAL SYSTEM INTO THE EASTERN STATES
VS GFS/GEFS SENDING IT OUT TO SEA. GIVEN THE PATTERN OF LATE NOD
GIVEN TO ECMWF/GEM...RESULTING IN ADDITION OF LOW END POPS TUESDAY
WHEN PROXIMITY OF ANY WRAP AROUND MSTR WOULD BE MOST FAVORABLE.
ALLBLEND RAN A BIT TOO HIGH SO WAS TEMPERED SOMEWHAT TO REMAIN
CONSERVATIVE.
&&
.AVIATION...
18Z TAFS...SEVERAL WEAK SHORT WAVES WILL CONTINUE TO ENHANCE
SHOWERS AND ISOLATED THUNDERSTORMS THROUGH MID AFTERNOON. AFTER
21Z...THE MORE PRONOUNCED OF THESE SHORT WAVES SHOULD BEGIN TO
SHIFT EAST OF THE TERMINALS...AND PRECIP COVERAGE IS EXPECTED TO
DIMINISH AFTER THIS TIME. HAVE MAINTAINED TEMPO MVFR CIGS AT KSBN
WHERE A PERIOD OF MORE SOLID RAIN SHOWERS IS EXPECTED THROUGH 20Z.
ANOTHER STRONGER SHORT WAVE NEAR STL SHOULD MAINTAIN A TRACK
PRIMARILY SOUTH OF THE TERMINALS...AND THUS WILL KEEP TAFS
TONIGHT. DESPITE SOME WEAK SFC BASED INSTABILITY EXPECTED AGAIN
FOR WEDNESDAY...BUILDING MID LEVEL HEIGHTS WILL RESULT IN DRY
CONDITIONS. SOME INCREASE IN SOUTH WINDS TOWARD THE END OF THE
PERIOD AS LOW LEVEL FLOW STRENGTHENS IN RESPONSE TO NEXT UPPER
LEVEL TROUGH DIGGING ACROSS THE ROCKIES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MARSILI
LONG TERM...FISHER
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1238 AM EDT TUE OCT 23 2012
.AVIATION...
A STATIONARY FRONT WAS JUST NORTH OF THE INDIANA LINE WITH SHOWERS
AND THUNDERSTORMS MOVING EAST ALONG AND NEAR THE FRONT. ADDED SOME
TEMPO IFR CIGS AT SBN 10-14Z GIVEN SOME UPSTREAM IFR CONDITIONS AND
THE ONGOING SHOWERS. THE LATEST GFS/LAMP GUIDANCE ALSO SUPPORTS
IFR CONDITIONS. OTHERWISE...CONDITIONS SHOULD GRADUALLY IMPROVE
LATER IN THE DAY AS WINDS CONTINUE FROM THE SOUTH. FWA SHOULD BE
MAINLY VFR...ALTHOUGH A TEMPO IFR AREA IS POSSIBLE EARLY THIS
MORNING.
&&
.PREV DISCUSSION... /ISSUED 320 PM EDT MON OCT 22 2012/
SHORT TERM... /TONIGHT THROUGH TUESDAY NIGHT/
COMPLEX SHORT TERM FORECAST GIVEN PROBLEMATIC MCV ROTATING THROUGH
WESTERN LAKES THIS AFTERNOON. CONVECTION HAS FIRED AHEAD OF MAIN
SHORT WAVE IN AREA OF STRONG THETA E ADVECTION WITH LOW LEVEL JET.
SATELLITE AND RADAR MOSAIC SHOWS MCV DEVELOPED OVER NORTHERN IL AND
LIFTING NORTH INTO WI. 12Z 4KM WRF WAS A TOTAL BUST WITH NO
INDICATION OF THIS LINE OF CONVECTION AT 18Z. HRRR WAS PERFORMING
WELL ON A FEW OF ITS RUNS AND GENERALLY FOLLOWED WITH SOME
EXTRAPOLATION. MOST SPECTRAL GUIDANCE DID NOT MODEL MCV AND
ASSOCIATED SUBSIDENCE IN ITS WAKE WHICH HAS LIMITED ANY FURTHER
DEVELOPMENT. SPECTRAL MODELS SEEM OVER AGGRESSIVE WITH ADDITIONAL
PCPN DEVELOPMENT THIS EVENING INTO EARLY OVERNIGHT HOURS IN AREA
NEAR WARM FRONT BUT BETWEEN SYNOPTIC SHORT WAVES. HAVE TIMED CURRENT
CONVECTION ACROSS CWA INTO EARLY EVENING HOURS WITH A DIMINISHING
TREND. KEPT CHANCE POPS GOING ENTIRE AREA THIS EVENING. SECOND SHORT
WAVE AND PV ANOMALY APPROACH LATE TONIGHT AND THIS FEATURE SLOWER
THAN PREVIOUS RUNS. NOW LOOKS LIKE THIS WILL IMPACT MOST OF AREA ON
TUESDAY. HAVE ADJUSTED TIMING/DETAIL OF POPS WITH LIKELY LATE
TONIGHT AND TUE MORNING ALL BUT SE AREAS. KEPT A CHANCE ACROSS
NORTHEAST TUE AFTERNOON WITH SHORT WAVE OVER THE AREA BUT MOVING
EAST. TEMPS WILL REMAIN WARM THROUGH THE PERIOD WITH LOWS IN UPPER
50S TO LOWER 60S. HIGHS ON TUE AGAIN TRICKY WITH CLOUDS AND PCPN BUT
SINCE WE MANAGED TO REACH 70 MOST AREAS TODAY SEE SIMILAR NUMBERS ON
TUE WITH MID 70S POSSIBLE SOUTH WHERE RAIN ENDS IN MORNING. BLENDED
GUIDANCE LOOKS GOOD.
LONG TERM... /WEDNESDAY THROUGH MONDAY/
UNSEASONABLY WARM WEATHER WILL BE IN STORE INTO THURSDAY WITH
CONTINUED SOUTHWESTERLY FLOW INTO THE REGION. MODELS IN GOOD
AGREEMENT THROUGH THURSDAY WITH 850 MB TEMPS IN THE +15 TO +17
CELSIUS RANGE. SOUNDINGS WOULD SUGGEST THAT TEMPS WILL ONLY MIX
THROUGH AROUND 900 MB YIELDING HIGHS IN THE MID TO UPPER 70S WEDS
AND THURS AFTERNOON WHICH IS INLINE WITH PREV GRIDS AND NEAR OR
ABOVE GUIDANCE. IF FULL MIX OUT THROUGH 850 MB OCCURS...TEMPS COULD
JUMP INTO THE LOWER 80S.
FORECAST BECOMES MORE MUDDLED THROUGH THE REMAINDER OF THE FORECAST
IN TERMS OF HANDLING OF SEVERAL LARGE SCALE FEATURES. FIRST IS LARGE
TROUGH WHICH WILL BE DIGGING INTO THE PLAINS WITH MAIN UPPER LEVEL
SYSTEM IN CENTRAL CANADA. THIS FEATURE DRIVES A STRONG COLD FRONT
THROUGH THE AREA IN THURS NGT/FRI TIME FRAME. FROM HERE THE MODELS
BEGIN TO DIVERGE ON HANDLING OF PROGRESSIVENESS OF THE TROUGH. 12Z
GFS HAS KEPT A POSITIVELY TILTED SYSTEM SWEEPING THROUGH AND COLDER
AIR ARRIVING BEHIND IT WITH LITTLE LINGERING PRECIP. 00Z ECMWF
STALLED THE FRONT ACROSS THE REGION WITH ADDITIONAL ENERGY MOVING
ALONG IT TO BRING CHANCES INTO SATURDAY. 12Z GEFS/GEM/00Z ECMWF THEN
INDICATE TROUGH BECOMES SOMEWHAT NEGATIVELY TILTED. THIS BRINGS TO
LIGHT THE 2ND FEATURE OF CONCERN...WHAT WILL LIKELY BECOME TROPICAL
SYSTEM SANDY LATER TODAY. MODELS GENERALLY INTENSIFY THE SYSTEM AND
TRACK INTO THE WESTERN ATLANTIC. THIS WILL CAUSE A BLOCKY PATTER TO
ESTABLISH WITH MODELS BOUNCING BACK AND FORTH ON POSSIBLE PHASING OF
SOME OF THE TROPICAL ENERGY AND THE TROUGH...DEVELOPING A LARGE
STORM SYSTEM THAT COULD BRING IN A BLAST OF COLD AIR AND CHANCES FOR
RAIN OR SNOW INTO NEXT WEEK. 12Z ECMWF HAS BACKED OFF ON MORE
WESTWARD SOLUTION OF THIS PHASING AND SOMEWHAT MORE REALISTIC
BOMBING OUT OF THE SYSTEM OFF THE EAST COAST. COLDER AIR WILL STILL
ARRIVE REGARDLESS WITH POTENTIAL FOR LAKE EFFECT POSSIBLY IN PLAY.
HAVE TRIED TO KEEP FOR THE MOST PART WITH PREV GRIDS AND UNDERCUT
GUIDANCE WITH TRENDS OF ALL MODELS STILL SUGGESTING A DROP TO WELL
BELOW NORMAL TEMPS. REMOVED SOME OF THE MIXED PRECIP WORDING WITH
1000-850 MB THICKNESS VALUES GENERALLY IN THE 1300 TO 1310 DM
RANGE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM...FISHER
AVIATION...SKIPPER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
507 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A WARM FRONT STALLING ACROSS LAKE ERIE AND NEW YORK STATE WILL CAUSE
SCATTERED SHOWERS TO MOVE EASTWARD ACROSS UPPER OHIO VALLEY INTO
WEDNESDAY MORNING...MAINLY NORTH OF PITTSBURGH. HIGH PRESSURE WILL
FOLLOW WITH DRY WARM WEATHER THURSDAY AND FRIDAY...BEFORE A STRONG
COLD FRONT BRINGS SHOWERS THIS WEEKEND AND A COOL DOWN FOR MUCH OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BASED ON BLEND OF RECENT RADAR DATA AND RAP MODEL OUTPUT...HAVE
ADJUSTED TIMING AND COVERAGE OF EASTBOUND ISOLATED SHOWERS ACROSS
THE UPPER OHIO VALLEY INTO MIDDAY. LIGHTNING DATA SHOWS NIL CLOUD
TO GROUND STRIKES...SO WILL CONTINUE NOT TO MENTION ANY THUNDER.
USING BLEND OF NAM AND GFS MODEL OUTPUT TO ADJUST SHOWER COVERAGE
THIS AFTERNOON AND TONIGHT...CONTINUED TO FORECAST A SLIGHTLY
HIGHER COVERAGE OF SHOWERS NORTH OF PITTSBURGH...WITH LITTLE IF
ANY SOUTH.
RECENT SREF MODEL OUTPUT SHOWS BROAD HIGH PRESSURE ACROSS
VIRGINIA AND THE CAROLINAS...EXPANDING NORTHWARD TOWARD THE UPPER
OHIO VALLEY TONIGHT AND WEDNESDAY. SO EXPECT LAST OF THE WARM FRONTAL
ISOLATED SHOWERS TO EXIT NORTHEAST PAST THE APPALACHIAN MOUNTAINS
BY MIDDAY WEDNESDAY. HIGH PRESSURE SUBSIDENCE WILL PROMOTE DRY
WARM CONDITIONS THE REST OF WEDNESDAY.
CONTINUED FORECAST OF TEMPERATURES TO BE AS MUCH AS 15 DEGREES
WARMER THAN NORMAL...AS SUPPORTED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
RECENT SREF MODEL OUTPUT SHOWS HIGH PRESSURE SUBSIDENCE
MAINTAINING DRY WARM CONDITIONS ACROSS THE UPPER OHIO VALLEY
THURSDAY AND FRIDAY.
CONTINUED FORECAST OF MUCH WARMER THAN NORMAL TEMPERATURES THIS
PERIOD WITH HIGHS THURSDAY NEARLY 20 DEGREES ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
BLEND OF RECENT GFS/ECMWF/NAEFS MODEL OUTPUT SHOW THE EASTWARD PASSAGE
OF A STRONG COLD FRONT THROUGH THE UPPER OHIO VALLEY
SATURDAY...WITH A CHANCE OF THE FIRST PREFRONTAL SHOWERS ARRIVING
LATE FRIDAY NIGHT. HAVE CONTINUED MENTION OF A CHANCE OF SHOWERS
SATURDAY INTO MONDAY...DUE TO FRONTAL DYNAMICS...POST SYSTEM COLD
INSTABILITY...AND POSSIBLE INTERACTION WITH A DEEPENING COASTAL
LOW PRESSURE SYSTEM.
FORECASTED TEMPERATURES TO COOL SHARPLY WITH THE COLD FRONTAL
PASSAGE SATURDAY...WITH TEMPERATURES GENERALLY 5 TO 10 DEGREES
COLDER THAN NORMAL SUNDAY AND MONDAY.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
SLIGHTLY BELOW NORMAL CONFIDENCE WITH 06Z TAFS. AT FKL/DUJ...MAIN
QUESTION IS WHETHER CONDITIONS MAY DROP TO MVFR DURING TIME PERIOD.
ELSEWHERE...CONDITIONS ARE EXPECTED TO REMAIN VFR...ALTHOUGH CLOUD
HEIGHTS ARE A BIT IN QUESTION. MODEL SOUNDINGS REALLY DON/T SEEM TO
HAVE MUCH AGREEMENT ON AMOUNT OF MOISTURE PRESENT. WILL STICK PRETTY
CLOSE TO INHERITED BKN CIGS AT MID LEVELS. SCATTERED SHOWERS SHOULD
NOT DROP MUCH FARTHER SOUTH THAN INTERSTATE 80. THINK THAT BULK OF
RAINFALL WILL REMAIN NORTH OF FKL/DUJ...SO WILL KEEP EXPLICIT RAIN
MENTION OUT OF TAFS AT THIS TIME.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL CONTINUE TO PREVAIL THROUGH DAYTIME FRIDAY.
RESTRICTIONS CAN OCCUR FRIDAY NIGHT AND SATURDAY DUE TO SHOWERS
ASSOCIATED WITH A STRONG COLD FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
200 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A WARM FRONT STALLING ACROSS LAKE ERIE AND NEW YORK STATE MAY
CAUSE SCATTERED SHOWERS TO MOVE EASTWARD ACROSS UPPER OHIO
VALLEY INTO WEDNESDAY MORNING...MAINLY NORTH OF PITTSBURGH. HIGH
PRESSURE WILL FOLLOW WITH DRY WARM WEATHER THURSDAY AND
FRIDAY...BEFORE A STRONG COLD FRONT BRINGS SHOWERS THIS WEEKEND AND
A COOL DOWN FOR MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
BASED ON BLEND OF RECENT RADAR DATA AND RAP MODEL OUTPUT...HAVE
ADJUSTED TIMING AND COVERAGE OF EASTBOUND ISOLATED SHOWERS ACROSS
THE UPPER OHIO VALLEY THROUGH THIS MORNING. LIGHTNING DATA SHOWS
ISOLATED THUNDERSTORMS OVER NORTHERN OHIO...HOWEVER EXPECT THESE
TO DIE BEFORE REACHING PLACES LIKE NEW PHILADELPHIA OHIO OR
FRANKLIN PENNSYLVANIA.
THEN USED BLEND OF NAM AND GFS MODEL OUTPUT TO ADJUST SHOWER
COVERAGE THIS AFTERNOON AND TONIGHT. COMPOSITE OF THIS MODEL
OUTPUT SHOW A HIGHER CHANCE OF SHOWERS NORTH OF PITTSBURGH THAN
SOUTH.
CONTINUED FORECAST OF TEMPERATURES TO BE AS MUCH AS 15 DEGREES
WARMER THAN NORMAL...AS SUPPORTED BY RECENT GFS AND NAM MOS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
RECENT SREF MODEL OUTPUT SHOWS BROAD HIGH PRESSURE ACROSS
VIRGINIA AND THE CAROLINAS...EXPANDING NORTHWARD TOWARD THE UPPER
OHIO VALLEY THIS PERIOD. SO EXPECT LAST OF THE WARM FRONTAL
ISOLATED SHOWERS TO EXIT NORTHEAST PAST THE APPALACHIAN MOUNTAINS
BY MIDDAY WEDNESDAY. HIGH PRESSURE SUBSIDENCE WILL PROMOTE DRY
WARM CONDITIONS THE REST OF WEDNESDAY AND THURSDAY.
CONTINUED FORECAST OF WARMER THAN NORMAL TEMPERATURES THIS PERIOD
WITH HIGHS THURSDAY NEARLY 20 DEGREES ABOVE NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THERE IS GFSE/ECMWF/NAEFS AGREEMENT THAT THE UPPER OHIO VALLEY
WILL CONTINUE TO BE IN A DRY AND WARM SOUTHWESTERLY FLOW THURSDAY
NIGHT THROUGH FRIDAY NIGHT. TEMPERATURES THROUGH THIS PERIOD WILL
BE AROUND 15 DEGREES ABOVE NORMAL.
A COLD FRONT IS PROGGED TO APPROACH FROM THE WEST ON FRIDAY NIGHT
AND CROSS THE FORECAST AREA ON SATURDAY. THERE IS STILL SOME
UNCERTAINTY IN REGARDS TO THE TIMING OF ITS PASSAGE AND DUE TO
THIS THE FORECAST DOES NOT WAVER TOO FAR FROM THE HPC SOLUTION.
AFTER THE COLD FRONT PASSES...THERE IS A QUITE A BIT OF
UNCERTAINTY FOR THE LATE WEEKEND INTO MONDAY. THE 00Z ECMWF/12Z
CANADIAN AMPLIFY A NORTHERN STREAM MID-LEVEL TROUGH AND BEGIN TO
TAP INTO TROPICAL MOISTURE FROM WHAT IS NOW TD 18. MEANWHILE...THE
12Z GFS INDICATES A MUCH FLATTER PATTERN...TAKING THE TROPICAL
SYSTEM FURTHER EASTWARD INTO THE ATLANTIC AND LEAVING THE UPPER
OHIO VALLEY IN A SOUTHWESTERLY FLOW. GIVEN THE HIGH DEGREE OF
UNCERTAINTY...THE FORECAST REMAINS FAIRLY CLOSE TO HPC AND ALSO
CONSIDERS THE NAEFS MEAN WITH LOW CHANCE POPS AND TEMPS 5 TO 10
DEGREES BELOW SEASONAL NORMALS.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
SLIGHTLY BELOW NORMAL CONFIDENCE WITH 06Z TAFS. AT FKL/DUJ...MAIN
QUESTION IS WHETHER CONDITIONS MAY DROP TO MVFR DURING TIME PERIOD.
ELSEWHERE...CONDITIONS ARE EXPECTED TO REMAIN VFR...ALTHOUGH CLOUD
HEIGHTS ARE A BIT IN QUESTION. MODEL SOUNDINGS REALLY DON/T SEEM TO
HAVE MUCH AGREEMENT ON AMOUNT OF MOISTURE PRESENT. WILL STICK PRETTY
CLOSE TO INHERITED BKN CIGS AT MID LEVELS. SCATTERED SHOWERS SHOULD
NOT DROP MUCH FARTHER SOUTH THAN INTERSTATE 80. THINK THAT BULK OF
RAINFALL WILL REMAIN NORTH OF FKL/DUJ...SO WILL KEEP EXPLICIT RAIN
MENTION OUT OF TAFS AT THIS TIME.
.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL CONTINUE TO PREVAIL UNTIL FRIDAY NIGHT AND
SATURDAY WHEN A COLD FRONT APPROACHES FROM THE WEST AND BRINGS
SHOWERS WITH RESTRICTIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EDT TUE OCT 23 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 447 PM EDT TUE OCT 23 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALF OVER
THE CENTRAL CONUS BTWN DEEP TROF ALONG THE PACIFIC COAST AND UPR RDG
OVER ERN NAMERICA. THERE IS AN AREA OF SHRA/SOME TS OVER MAINLY THE
WRN CWA ASSOCIATED WITH A DISTURBANCE MOVING NEWD TO THE N OF H85
WARM FNT STRETCHING FM THE NRN PLAINS INTO THE UPR MIDWEST AND
ACCOMPANYING SHARPER H85-5 QVECTOR CNVGC/ISENTROPIC ASCENT BEST
SHOWN ON THE 300K SFC IN THE PRESENCE OF STEEP H85-5 LAPSE RATES
SHOWN ON THE 12Z MPX RAOB. SMALL HAIL FELL FM A FEW OF THE STRONGER
CELLS OVER THE WRN CWA/NW WI EARLIER. THE E HALF OF THE CWA HAS BEEN
MAINLY PCPN FREE WITH A DRIER/MORE STABLE PROFILE SHOWN ON THE 12Z
APX RAOB. EXCEPT FOR A CLUSTER OF SHRA/EMBEDDED TS OVER SCNTRL
WI...AREAS TO THE SW OF H85 WARM FNT ARE GENERALLY DRY WITH STRONG
CAP SHOWN ON THE 12Z ABERDEEN SDAKOTA RAOB DOMINATING. HOWEVER...
THERE IS QUITE A BIT OF LO CLD AND FOG WITH ABUNDANT LLVL MSTR/SFC
DEWPTS AN UNSEASONABLY HI 55 TO 60.
LATE THIS AFTN...AS AREA OF SHARPER ISENTROPIC ASCENT/DEEP LYR
QVECTOR CNVGC SUPPORTING THE NMRS SHRA/ISOLD TS OVER THE WRN CWA
EARLY THIS AFTN SHIFTS TO THE N...EXPECT DIMINISHING POPS S-N OVER
THE W. WITH ABSENCE OF UPR SUPPORT FOR PCPN OVER THE E HALF...
EXPECT ONLY ISOLD-SCT -SHRA IN THIS AREA. THE ONLY EXCEPTION MIGHT
BE THE SCNTRL...WHERE AREA OF SHRA NOW OVER WI AND DRIFTING TO THE
NE WILL BRUSH THE AREA.
TONIGHT...AS MAIN SHRTWV IN THE NRN PLAINS MOVG NEWD WELL TO THE W
LIFTS INTO SCNTRL CAN...UPR HGTS ARE FCST TO RISE SLOWLY OVER THE
CWA WITH AREA OF DEEP LYR QVECTOR CNVGC LIFTING TO THE N AND AWAY FM
UPR MI. WITH LACK OF DYANMIC SUPPORT AND FCST SDNGS HINTING AT MID
LVL DRYING/CAPPING AS SHOWN ON THE ABERDEEN RAOB...SUSPECT THERE WL
BE NOTHING MORE THAN ISOLD-SCT -SHRA WITH THE GREATER POPS THIS EVNG
OVER THE KEWEENAW INTO NCNTRL LK SUP. OTRW...INFLUX OF LLVL MSTR
WITH FLOW VEERING MORE TO THE S WL SUPPORT AREAS OF FOG...
ESPECIALLY OVER THE CNTRL CWA WITH UPSLOPE SE VEERING S FLOW. FOG IN
THIS AREA MIGHT BECOME DENSE. EXPECT LTL DIURNAL FALL OF TEMP WITH
INFLUX OF LLVL MSTR.
WED...COLD FNT ATTENDANT TO SHRTWV LIFTING TO THE NE THRU CNTRL
CANADA WL LIMP INTO THE WRN ZNS IN THE MRNG. SINCE THERE WL BE LTL
IN THE WAY OF LARGE SCALE FORCING AT THAT TIME...EXPECT NOTHING MORE
THAN SCT -SHRA TO ACCOMPANY ITS ARRIVAL. HOWEVER...APRCH OF MORE
SGNFT SHRTWV LIFTING OUT OF WRN TROF IN THE AFTN WL SUPPORT HIER
POPS THERE IN THE AFTN...WITH LOWER POPS TO THE E TOWARD HIER H5
HGTS AND AWAY FM INCOMING DEEP LYR QVECTOR CVNGC/FGEN/MSTR CNVGC
ALONG BNDRY. STEEP H7-5 LAPSE RATES SUPPORT MENTION OF TS. AREAS OF
FOG WL LIKELY PERSIST MUCH OF THE DAY UNDER CONSIDERABLE CLD
COVER...ESPECIALLY OVER THE CNTRL WITH PERSISTENT UPSLOPE LLVL FLOW.
ALTHOUGH TEMPS WL BE WELL ABV NORMAL...TENDED TO LOWER GOING FCST
MAX TEMPS A BIT TO ACCOUNT FOR EXPECTED FOG/CLD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 447 PM EDT TUE OCT 23 2012
THE 500MB RIDGE WILL BE JUST TO OUR EAST /STRETCHING THROUGH THE
LOWER GREAT LAKES AND HUDSON BAY...WITH A WELL FORECASTED LOW
PUSHING IN FROM CENTRAL CANADA. SW FLOW ALOFT WILL REMAIN OVERHEAD
THROUGH SATURDAY NIGHT AS THE 500MB LOW SHIFTS FROM AROUND LAKE
WINNIPEG AT 00Z FRIDAY TO S HUDSON BAY FRIDAY...BEFORE EJECTING N
SATURDAY.
THE BEST CHANCE OF SHOWERS THROUGH THE ENTIRE EXTENDED LOOKS TO BE
WEDNESDAY NIGHT...THEN PUSHING W TO E DURING THE DAY THURSDAY AS THE
ELONGATED SFC LOW STRETCHING FROM THE KEWEENAW THROUGH N TX AT 06Z
THURSDAY DEEPENS SLIGHTLY AS IT PUSHES ACROSS LAKE SUPERIOR DURING
THE AFTERNOON HOURS...AND INTO NE ONTARIO BY 00Z FRIDAY. A FEW
THUNDERSTORMS WILL BE POSSIBLE MAINLY OVER THE W HALF WEDNESDAY
NIGHT...THEN CENTRAL AND E THURSDAY. THE SWATH OF HEAVIEST RAIN
/OVER AN INCH FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING/ LOOKS
TO HAVE SHIFTED SLIGHTLY WESTWARD. THIS INCLUDES AREAS FROM IWD
THROUGH CRYSTAL FALLS...AND N THROUGH THE KEWEENAW PENINSULA. THE
FAR EAST THIRD OF THE CWA MAY BE LUCKY TO RECEIVE HALF AN INCH BY
THE TIME IT IS DONE. A FEW SNOWFLAKES COULD MIX IN OVER INTERIOR W
LOCATIONS THURSDAY NIGHT AS COLD AIR WRAPS IN.
THE 23/00Z CANADIAN BRINGS A SECONDARY WAVE THAT LINGERED OVER LAKE
WINNIPEG AT 06Z FRIDAY...SLOWLY PUSHING IT TO JUST NW OF LAKE
SUPERIOR BY DAYBREAK SATURDAY...AND STILL JUST N OF THE LAKE SUNDAY
AFTERNOON. WHILE A TROUGH WILL LIKELY RESIDE NEAR LAKE SUPERIOR
THROUGH MUCH OF THIS TIME PERIOD...THE CANADIAN LOOKS TO BE A BIT
TOO STRONG/DEEP WITH THE FEATURE /AT LEAST A LITTLE TOO EARLY/. AS A
RESULT...WITH LEAN CLOSER TO THE ECMWF...AND UTILIZE A LITTLE LESS
OF THE CANADIAN OUTPUT FROM FRIDAY AFTERNOON ON.
THE 500MB TROUGH WILL LINGER OVERHEAD FROM SATURDAY THROUGH AT LEAST
SUNDAY NIGHT...AS A SFC HIGH PUSHES IN FROM THE W. BY SUNDAY NIGHT
THE GFS AND ECMWF SPLIT WAYS...ESPECIALLY WITH THE HANDLING OF THE
SYSTEM OFF THE EAST COAST. A MIX OF RAIN AND MOSTLY SNOW WILL BE
POSSIBLE SATURDAY...WITH ONSHORE ENHANCEMENT SATURDAY NIGHT OVER
THE KEWEENAW PENINSULA AS 850MB TEMPS COOL TO AROUND -9C. LOOKING AT
THE FCST MODELS CLOSER TO HOME THE GFS REMAINS MORE PROGRESSIVE...AS
AN ADDITIONAL 500MB LOW NEARS FROM S CENTRAL CANADA MONDAY NIGHT.
THE RESULT WOULD BE BRIEF RIDGING OVER THE UPPER GREAT LAKES MONDAY.
THE ECMWF ON THE OTHER HAND SINKS/WRAPS UP A LOW OVER THE OHIO
VALLEY. WILL NOT GET TOO SPECIFIC...BUT WILL LIMIT THE QUICKER
INFLUENCE OF THE NORTHERN LOW NEARING THE CWA ON DAY 6/7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 128 PM EDT TUE OCT 23 2012
AS VEERING LLVL FLOW SHIFTING TO THE S ADVECTS MORE LLVL MSTR INTO
THE AREA...EXPECT IFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD.
DOWNSLOPE NATURE OF THE FLOW MAY LIMIT THE DROP IN CIG/VSBY AT
CMX/IWD AT TIMES THIS AFTN/TNGT...BUT WEAKENING WINDS WITH APRCH OF
LO PRES TROF LATER IN THE TAF PERIOD INDICATES LIFR CONDITIONS WL
PREDOMINATE AT THOSE SITES ON WED MRNG. AT SAW...THE SE-S WIND WL
UPSLOPE AND PRESENT A GREATER CHANCE FOR LIFR CONDITIONS. OTRW...
-SHRA WL IMPACT MAINLY CMX THIS AFTN...AND THERE COULD BE A TS THERE
AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT TUE OCT 23 2012
EXPECT E WINDS UP TO 30 KTS THIS EVENING...WITH A FEW GALE FORCE
GUSTS TO 35 KTS WHERE TERRAIN ENHANCES THESE WINDS OVER THE
NCENTRAL. ALTHOUGH THE STRONGER SE FLOW WILL PERSIST OVER THE E HALF
OVERNIGHT...THE WINDS WILL DIMINISH OVER THE W AFTER MIDNIGHT AS
SHARPER PRES GRADIENT SHIFTS TO THE NE IN ADVANCE OF AN APPROACHING
COLD FRONT. THIS WEAKER PRES GRADIENT WILL OVERSPREAD THE ENTIRE
LAKE ON WED...RESULTING IN DIMINISHING WINDS EVEN OVER THE E HALF.
SOME FOG IS LIKELY TO DEVELOP OVER THE W FOLLOWING THE COLD FROPA. A
NEW LOW WILL ORGANIZE ACROSS THE CENTRAL PLAINS WEDNESDAY AND LIFT
NORTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY...WITH A FEW GALE FORCE
GUSTS OF 35KTS POSSIBLE OVER MAINLY CENTRAL LAKE SUPERIOR THURSDAY
NIGHT. A RIDGE OF HIGH PRESSURE WILL THEN BUILD INTO THE REGION
FRIDAY THROUGH SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
916 PM CDT WED OCT 24 2012
.UPDATE...
A TWO HEADED CONCERN CONTINUES TONIGHT. THE FIRST IS THE SEVERE
WEATHER RISK WHICH APPEARS CONDITIONAL THIS EVENING. THE FRONT
REMAINS STATIONARY FROM CENTRAL IA TO NEAR ROCHESTER...EAU
CLAIRE..AND NC WI. THE ATMOSPHERE REMAINS RATHER UNSTABLE EAST OF
THE FRONT WITH TEMPERATURES STILL IN THE 60S AND 70S. ELEVATED
INSTABILITY IS ALSO PRESENT BEHIND THE FRONT AS FAR WEST AS THE
TWIN CITIES. CELLS HAVE BEGUN TO GROW MORE NUMEROUS IN THE PAST
HOUR OR SO ACROSS NERN IA AND FAR SERN MN WHICH COULD BE A SIGN
THE CAP IS ERODING SLOWLY. WARM MID LEVEL TEMPERATURES AHEAD OF
THE FRONT AND MOST OF THE FORCING BEING CONFINED TO BEHIND THE
FRONT HAVE INHIBITED SEVERE ACTIVITY SO FAR. AS THE IMPULSE IN THE
PLAINS CONTINUES TO TRANSLATE EASTWARD...MID LEVEL TEMPS SHOULD
COOL AND ALLOW THE CAP TO BREAK. LARGE HAIL IS THE MAIN
THREAT...BUT A TORNADO CANNOT BE RULED OUT EITHER GIVEN IMPRESSIVE
VEERING PROFILES. AFOREMENTIONED STEEP MID LEVEL LAPSE RATES POST
FRONTAL COULD ALSO SUPPORT SOME HAIL...MAINLY EAST OF A LINE FROM
AEL TO RNH.
LATER TONIGHT...WIDESPREAD PRECIPITATION WILL DEVELOP ACROSS SRN
AND CNTRL MN AS THE FINAL WAVE EJECTS INTO THE UPPER MISSISSIPPI
VALLEY. PRECIPITATION SHOULD START AS ALL RAIN...BUT WILL GRADUALLY
TRANSITION TO SNOW FROM WEST TO EAST THROUGH THE LATE OVERNIGHT
INTO THURSDAY MORNING AS COLDER AIR WRAPS INTO THE SYSTEM. MODELS
ARE IN FAIRLY GOOD AGREEMENT WITH THE POTENTIAL FOR ACCUMULATING
SNOW WEST OF A LINE FROM REDWOOD FALLS TO ST CLOUD DURING THIS
TIME. HOWEVER...THE 00Z NAM NOW HAS THE 0C 925 MB LINE AS FAR
EAST AS FAIRMONT...MANKATO...AND CAMBRIDGE - SIGNALING THE
POTENTIAL FOR MAX ACCUMULATIONS ALONG AN AXIS FROM REDWOOD FALLS
TO ST CLOUD. SNOW MAY FALL AT A DECENT RATE WITH THE AMOUNT OF
FRONTOGENETIC FORCING AND MOISTURE PRESENT. THIS COINCIDES WITH
THE DGZ...SO DENDRITES ARE EXPECTED. THE BIG QUESTION IS WHEN IT
WILL TRANSITION AND HOW COLD TEMPERATURES ULTIMATELY GET. WITH THE
WARMER GROUND TEMPERATURES AND WET CONDITIONS...IT WILL TAKE AN
EFFORT TO GET SNOW TO STICK INITIALLY WITH TEMPS HOVERING AROUND 32.
BRIDGES AND OVERPASSES WILL BE THE FIRST TO FREEZE...WITH ELEVATED
AND GRASSY SURFACES LIKELY TO EXPERIENCE THE ACCUMULATING SNOW.
WITH SO MANY INHIBITING FACTORS FOR ACCUMULATING SNOW ON
ROADWAYS...WILL HOLD OFF ON A WINTER WEATHER ADVISORY AND ADDRESS
THE THREAT WITH A SPECIAL WEATHER STATEMENT.
BORGHOFF
&&
.PREV DISCUSSION...
/ISSUED 346 PM CDT WED OCT 24 2012/
OVERVIEW...NEARLY ALL OF THE FORECAST CONCERNS ARE CONFINED TO THE
NEXT 18-24 HOURS WITH CURRENT INVERTED TROUGH IN THE PLAINS AND
UPPER MISSISSIPPI RIVER VALLEY. DRIZZLE WILL BE REPLACED BY STEADY
MODERATE RAIN WITH EMBEDDED THUNDERSTORMS AS TROUGH APPROACHES AND
SURFACE CYCLONE DEVELOPS AS IT LEFTS NORTH. SEVERE WEATHER STILL
REMAINS...BUT MAIN OVER AREA OF CONCERN IS TO THE SOUTHEAST OF THE
MPX FORECAST AREA. 12Z GFS/NAM HAVE BOTH TRENDED THE CHANGE OVER
TO SNOW A LITTLE FASTER LATE TONIGHT...SO 1-2 INCHES OF SLUSH IS
STILL POSSIBLE ACROSS PORTIONS OF CENTRAL MINNESOTA.
BROAD AREA OF MSLP PRESSURE FALLS ACROSS EASTERN MN AND WESTERN WI
THIS AFTERNOON...ON THE ORDER OF 0.5MB PER HOUR. SO THE SYSTEM IS
EVOLVING ON COURSE WITH THE MOST OF THE AVAILABLE 12Z MODEL
OUTPUT. THE LAST THREE RUNS OF THE NAM HAVE BEEN REMARKABLY
CONSISTENT WITH THE LOW TRACK. FURTHERMORE...THE 12Z NAM AND ECMWF
ARE ALSO VERY ALIKE IN HOW THEY EVOLVE THINGS OVER THE NEXT 24
HOURS...SO TRENDED THE POPS/WEATHER TOWARD A BLEND OF THE TWO. THE
GFS HAS BEEN ON THE SLOWER END OF THE MODEL SOLUTION ENVELOPE FOR
THE PAST COUPLE DAYS NOW AND IT ACTUALLY IS STILL PROBABLY ABOUT 3
HOURS SLOWER THE NAM AND ECMWF. WESTERN EDGE OF 500-1000 J/KG
MUCAPE AND BEST LI NEAR ZERO EXTENDS ROUGHLY FROM BLUE EARTH TO
THE WESTERN TWIN CITIES METRO...TO HINCKLEY. THIS INSTABILITY AXIS HAS
SLOWLY CREPT EAST TODAY...BUT WITH LITTLE MOVEMENT OVER THE PAST
COUPLE HOURS. THIS TO GO ALONG WITH TEMPERATURES THAT HAVE
UNDERACHIEVED GIVEN THE FOG AND STRATUS. OUTSIDE OF WEST CENTRAL
WI AND SOUTHEAST MN...SURFACE WINDS ARE NORTHERLY AND AXIS OF
SURFACE BASED CAPE IS IN SOUTHEAST MN...WISCONSIN AND EASTERN IA.
THUS...THE SEVERE THREAT LOOKS MAINLY SOUTHEAST OF THE AREA.
ACTUALLY SURPRISED SPC DIDN`T NUDGE THE SLIGHT RISK A BIT FARTHER
EAST WITH THE 20Z UPDATE...BUT STILL CLOSE I SUPPOSE. ONE THINGS
FOR SURE HOWEVER...SFC-850MB FGEN IS REALLY CRANKING UP ACROSS
EASTERN MN AND WESTERN WI...THUS THE EXPANSE OF MORE LIGHT
SHOWERS...AS OPPOSED TO DRIZZLE. THIS TREND WILL CONTINUE TONIGHT
AND UPDRAFTS SHOULD BECOME MORE VIGOROUS AS UPPER WAVE DRAWS NEARER
AND MID LEVEL TEMPS COOL. 850MB MOISTURE TRANSPORT SHOWS A RIBBON
OF MOISTURE STREAMING FROM SW-NE ACROSS WESTERN WI ALL NIGHT.
THE COBB/CARIBOU SNOW TECHNIQUE OFF THE NAM/GFS HAS TRENDED A BIT
MORE FAVORABLE FOR SNOW IN THE PAST COUPLE RUNS - EVEN BRINGING
ACCUMULATIONS NEAR ONE INCH AS FAR EAST AS THE WESTERN TWIN CITIES
SUBURBS BY MID MORNING TOMORROW. NEAR SURFACE TEMPS ARE A
CONCERN...ESPECIALLY IN THE METRO. EVEN WITH COLLAPSING HEIGHTS
AND SOLID FORCING...WONDERING IF WE MIGHT JUST BE A FEW DEGREES
TOO WARM IN THE LOWEST 1000 FT OR SO FOR MUCH SNOW. HOWEVER...MUCH
OF WESTERN MN COULD SEE AN INCH OF SLUSHY ACCUMULATION AND
POSSIBLY A COUPLE INCHES DEPENDING ON HOW FAST THE CHANGEOVER
HAPPENS TONIGHT. HPC WWD HAS 1-2" IN WESTERN PORTIONS OF THE MPX
FORECAST AREA.
WITH THE SLIGHTLY FASTER NAM/EC BLENDED SOLUTION...HAVE MUCH OF THE
PRECIP OUT OF MN BY 18Z TOMORROW...AND 00Z IN WESTERN WI. MUCH
COOLER NORTHWEST FLOW BEHIND THE SYSTEM AND CANADIAN HIGH SETTLING
IN SUGGEST A COLD WEEKEND ACROSS THE AREA. HAVE WIDESPREAD 20S
FOR LOWS IN THE FORECAST AREA...BUT THINKING IF WE GET A GOOD
RADIATIONAL COOLING NIGHT SATURDAY OR SUNDAY TEENS ARE QUITE
POSSIBLE OUTSIDE OF THE CORE TWIN CITIES METRO. NOT A WHOLE LOT
IN THE WAY OF PRECIP ONCE YOU GET PAST TOMORROW...BUT INCOMING
SHORTWAVE ENERGY SATURDAY NIGHT COULD BRING LIGHT SNOW SHOWERS TO
MN/WI. THE BELOW NORMAL TEMPS ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION.../00Z TAF ISSUANCE/
FRONT IN THE PROCESS OF CLEARING EAU AT THE START OF PERIOD.
STRONG FRONTAL FORCING BEHIND THE FRONT ACROSS WRN WI HAS RESULTED
IN THE DEVELOPMENT OF A LINE OF -TSRA FROM NRN INTO CENTRAL WI
THAT WILL CONTINUE TO PUSH EAST. IN ITS WAKE...AREA WILL SEE A
BREAK FROM ANYTHING OUTSIDE OF DRIZZLE UNTIL MAIN WAVE SWINGS
THROUGH TONIGHT...ALONG WITH SEVERAL HOURS OF VFR CONDS FOR
CENTRAL/WRN MN PER OBS AND SREF PROBS FOR CIGS LESS THAN 3K FT. HI
RES MODELS ALL SIMILAR WITH SHIELD OF -RA COMING OUT OF THE OMAHA
AREA...AND HEADING UP INTO SRN MN INTO WRN WI. USED HRRR/ARW REFL
FORECASTS TO TIME RETURN OF RAIN AFTER 09Z. P-TYPE WILL ALSO BE AN
ISSUE FOR AXN/RWF/STC. AGAIN HI-RES MODELS ALONG WITH THE NAM ALL
SIMILAR WITH CHANGING PRECIP OVER TO SNOW BY THE MORNING. IN
ADDITION...THE HRRR SHOWS A BAND OF 2-4 INCHES OF SNOW FROM
GRANITE FALL TO LONG PRAIRIE WEST...WITH THE 18Z NAM SHOWING A
SIMILAR BAND SLIGHTLY FARTHER EAST. FAVORED A NAM FORECAST AT THIS
POINT...INDICATING 3/4SM -SN AT RWF...BUT CONFIDENCE IS
INCREASING THAT AXN AND/OR RWF WILL SEE A PERIOD OF 1/2SM OR LESS
MODERATE SNOW IN THE MORNING /SEE SNOW OBS IN WRN NEB/ WITH A
SLUSHY INCH OR TWO OF ACCUMULATIONS. THIS PRECIP WILL BE
ACCOMPANIED BY IFR/LIFR CIGS. FORTUNATELY...THIS BAND WILL BE FAIRLY
TRANSIENT...QUICKLY MOVING ACROSS MN DURING THE MORNING AND WI
TERMINALS IN THE AFTERNOON. ALL TERMINALS WILL LIKELY BE VFR/SKC
BY THE END OF THE TAF. FOR WINDS...GRADIENT WILL BE TIGHT...SO
LOOKS GOOD FOR SUSTAINED WINDS UP AROUND 15 KTS...WITH MIX DOWN
POTENTIAL FROM THE NAM SHOWING GUSTS UP TO 30 KTS POSSIBLE.
KMSP...AT THE MOMENT...EXPECT NW WINDS TO BRING HIGH MVFR/VFR
CONDITIONS NW OF FIELD DOWN BETWEEN 2 AND 4Z...THOUGH SREF MVFR
CIG PROBS DO SHOW THESE CONDITIONS MAKING IT TO MSP AND NOT MUCH
FARTHER. REGARDLESS OF WHAT HAPPENS WITH THE HIGHER CIGS...THEY
WILL GO BACK IFR WITH THE ARRIVAL OF THE NEXT ROUND OF
PRECIP...WHICH THE HRRR BRINGS IN AT ABOUT 10Z. AS THE PRECIP IS
MOVING OUT...SOUNDINGS DO INDICATE BEING COLD ENOUGH FOR APOSSIBLE
RASN MIX BETWEEN 15Z AND 18Z..BUT AS MENTIONED IN DISCUSSION
ABOVE...THERE ARE QUESTIONS IF THE LOWEST LEVELS OF THE ATMO WILL
COOL ENOUGH TO ALLOW SNOW TO REACH THE GROUND AND GIVEN THE
UNCERTAINTIES...LEFT IT OUT FOR NOW.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS WNW 10G20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...VFR. SLIGHT CHANCE -RASH. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
736 PM CDT WED OCT 24 2012
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
OVERVIEW...NEARLY ALL OF THE FORECAST CONCERNS ARE CONFINED TO THE
NEXT 18-24 HOURS WITH CURRENT INVERTED TROUGH IN THE PLAINS AND
UPPER MISSISSIPPI RIVER VALLEY. DRIZZLE WILL BE REPLACED BY STEADY
MODERATE RAIN WITH EMBEDDED THUNDERSTORMS AS TROUGH APPROACHES AND
SURFACE CYCLONE DEVELOPS AS IT LEFTS NORTH. SEVERE WEATHER STILL
REMAINS...BUT MAIN OVER AREA OF CONCERN IS TO THE SOUTHEAST OF THE
MPX FORECAST AREA. 12Z GFS/NAM HAVE BOTH TRENDED THE CHANGE OVER
TO SNOW A LITTLE FASTER LATE TONIGHT...SO 1-2 INCHES OF SLUSH IS
STILL POSSIBLE ACROSS PORTIONS OF CENTRAL MINNESOTA.
BROAD AREA OF MSLP PRESSURE FALLS ACROSS EASTERN MN AND WESTERN WI
THIS AFTERNOON...ON THE ORDER OF 0.5MB PER HOUR. SO THE SYSTEM IS
EVOLVING ON COURSE WITH THE MOST OF THE AVAILABLE 12Z MODEL
OUTPUT. THE LAST THREE RUNS OF THE NAM HAVE BEEN REMARKABLY
CONSISTENT WITH THE LOW TRACK. FURTHERMORE...THE 12Z NAM AND ECMWF
ARE ALSO VERY ALIKE IN HOW THEY EVOLVE THINGS OVER THE NEXT 24
HOURS...SO TRENDED THE POPS/WEATHER TOWARD A BLEND OF THE TWO. THE
GFS HAS BEEN ON THE SLOWER END OF THE MODEL SOLUTION ENVELOPE FOR
THE PAST COUPLE DAYS NOW AND IT ACTUALLY IS STILL PROBABLY ABOUT 3
HOURS SLOWER THE NAM AND ECMWF. WESTERN EDGE OF 500-1000 J/KG
MUCAPE AND BEST LI NEAR ZERO EXTENDS ROUGHLY FROM BLUE EARTH TO
THE WESTERN TWIN CITIES METRO...TO HINCKLEY. THIS INSTABILITY AXIS HAS
SLOWLY CREPT EAST TODAY...BUT WITH LITTLE MOVEMENT OVER THE PAST
COUPLE HOURS. THIS TO GO ALONG WITH TEMPERATURES THAT HAVE
UNDERACHIEVED GIVEN THE FOG AND STRATUS. OUTSIDE OF WEST CENTRAL
WI AND SOUTHEAST MN...SURFACE WINDS ARE NORTHERLY AND AXIS OF
SURFACE BASED CAPE IS IN SOUTHEAST MN...WISCONSIN AND EASTERN IA.
THUS...THE SEVERE THREAT LOOKS MAINLY SOUTHEAST OF THE AREA.
ACTUALLY SURPRISED SPC DIDN`T NUDGE THE SLIGHT RISK A BIT FARTHER
EAST WITH THE 20Z UPDATE...BUT STILL CLOSE I SUPPOSE. ONE THINGS
FOR SURE HOWEVER...SFC-850MB FGEN IS REALLY CRANKING UP ACROSS
EASTERN MN AND WESTERN WI...THUS THE EXPANSE OF MORE LIGHT
SHOWERS...AS OPPOSED TO DRIZZLE. THIS TREND WILL CONTINUE TONIGHT
AND UPDRAFTS SHOULD BECOME MORE VIGOROUS AS UPPER WAVE DRAWS NEARER
AND MID LEVEL TEMPS COOL. 850MB MOISTURE TRANSPORT SHOWS A RIBBON
OF MOISTURE STREAMING FROM SW-NE ACROSS WESTERN WI ALL NIGHT.
THE COBB/CARIBOU SNOW TECHNIQUE OFF THE NAM/GFS HAS TRENDED A BIT
MORE FAVORABLE FOR SNOW IN THE PAST COUPLE RUNS - EVEN BRINGING
ACCUMULATIONS NEAR ONE INCH AS FAR EAST AS THE WESTERN TWIN CITIES
SUBURBS BY MID MORNING TOMORROW. NEAR SURFACE TEMPS ARE A
CONCERN...ESPECIALLY IN THE METRO. EVEN WITH COLLAPSING HEIGHTS
AND SOLID FORCING...WONDERING IF WE MIGHT JUST BE A FEW DEGREES
TOO WARM IN THE LOWEST 1000 FT OR SO FOR MUCH SNOW. HOWEVER...MUCH
OF WESTERN MN COULD SEE AN INCH OF SLUSHY ACCUMULATION AND
POSSIBLY A COUPLE INCHES DEPENDING ON HOW FAST THE CHANGEOVER
HAPPENS TONIGHT. HPC WWD HAS 1-2" IN WESTERN PORTIONS OF THE MPX
FORECAST AREA.
WITH THE SLIGHTLY FASTER NAM/EC BLENDED SOLUTION...HAVE MUCH OF THE
PRECIP OUT OF MN BY 18Z TOMORROW...AND 00Z IN WESTERN WI. MUCH
COOLER NORTHWEST FLOW BEHIND THE SYSTEM AND CANADIAN HIGH SETTLING
IN SUGGEST A COLD WEEKEND ACROSS THE AREA. HAVE WIDESPREAD 20S
FOR LOWS IN THE FORECAST AREA...BUT THINKING IF WE GET A GOOD
RADIATIONAL COOLING NIGHT SATURDAY OR SUNDAY TEENS ARE QUITE
POSSIBLE OUTSIDE OF THE CORE TWIN CITIES METRO. NOT A WHOLE LOT
IN THE WAY OF PRECIP ONCE YOU GET PAST TOMORROW...BUT INCOMING
SHORTWAVE ENERGY SATURDAY NIGHT COULD BRING LIGHT SNOW SHOWERS TO
MN/WI. THE BELOW NORMAL TEMPS ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION.../00Z TAF ISSUANCE/
FRONT IN THE PROCESS OF CLEARING EAU AT THE START OF PERIOD.
STRONG FRONTAL FORCING BEHIND THE FRONT ACROSS WRN WI HAS RESULTED
IN THE DEVELOPMENT OF A LINE OF -TSRA FROM NRN INTO CENTRAL WI
THAT WILL CONTINUE TO PUSH EAST. IN ITS WAKE...AREA WILL SEE A
BREAK FROM ANYTHING OUTSIDE OF DRIZZLE UNTIL MAIN WAVE SWINGS
THROUGH TONIGHT...ALONG WITH SEVERAL HOURS OF VFR CONDS FOR
CENTRAL/WRN MN PER OBS AND SREF PROBS FOR CIGS LESS THAN 3K FT. HI
RES MODELS ALL SIMILAR WITH SHIELD OF -RA COMING OUT OF THE OMAHA
AREA...AND HEADING UP INTO SRN MN INTO WRN WI. USED HRRR/ARW REFL
FORECASTS TO TIME RETURN OF RAIN AFTER 09Z. P-TYPE WILL ALSO BE AN
ISSUE FOR AXN/RWF/STC. AGAIN HI-RES MODELS ALONG WITH THE NAM ALL
SIMILAR WITH CHANGING PRECIP OVER TO SNOW BY THE MORNING. IN
ADDITION...THE HRRR SHOWS A BAND OF 2-4 INCHES OF SNOW FROM
GRANITE FALL TO LONG PRAIRIE WEST...WITH THE 18Z NAM SHOWING A
SIMILAR BAND SLIGHTLY FARTHER EAST. FAVORED A NAM FORECAST AT THIS
POINT...INDICATING 3/4SM -SN AT RWF...BUT CONFIDENCE IS
INCREASING THAT AXN AND/OR RWF WILL SEE A PERIOD OF 1/2SM OR LESS
MODERATE SNOW IN THE MORNING /SEE SNOW OBS IN WRN NEB/ WITH A
SLUSHY INCH OR TWO OF ACCUMULATIONS. THIS PRECIP WILL BE
ACCOMPANIED BY IFR/LIFR CIGS. FORTUNATELY...THIS BAND WILL BE FAIRLY
TRANSIENT...QUICKLY MOVING ACROSS MN DURING THE MORNING AND WI
TERMINALS IN THE AFTERNOON. ALL TERMINALS WILL LIKELY BE VFR/SKC
BY THE END OF THE TAF. FOR WINDS...GRADIENT WILL BE TIGHT...SO
LOOKS GOOD FOR SUSTAINED WINDS UP AROUND 15 KTS...WITH MIX DOWN
POTENTIAL FROM THE NAM SHOWING GUSTS UP TO 30 KTS POSSIBLE.
KMSP...AT THE MOMENT...EXPECT NW WINDS TO BRING HIGH MVFR/VFR
CONDITIONS NW OF FIELD DOWN BETWEEN 2 AND 4Z...THOUGH SREF MVFR
CIG PROBS DO SHOW THESE CONDITIONS MAKING IT TO MSP AND NOT MUCH
FARTHER. REGARDLESS OF WHAT HAPPENS WITH THE HIGHER CIGS...THEY
WILL GO BACK IFR WITH THE ARRIVAL OF THE NEXT ROUND OF
PRECIP...WHICH THE HRRR BRINGS IN AT ABOUT 10Z. AS THE PRECIP IS
MOVING OUT...SOUNDINGS DO INDICATE BEING COLD ENOUGH FOR APOSSIBLE
RASN MIX BETWEEN 15Z AND 18Z..BUT AS MENTIONED IN DISCUSSION
ABOVE...THERE ARE QUESTIONS IF THE LOWEST LEVELS OF THE ATMO WILL
COOL ENOUGH TO ALLOW SNOW TO REACH THE GROUND AND GIVEN THE
UNCERTAINTIES...LEFT IT OUT FOR NOW.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS WNW 10G20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...VFR. SLIGHT CHANCE -RASH. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
315 AM CDT TUE OCT 23 2012
.DISCUSSION...
SHRTWV ACROSS EASTERN SD/NE NEBRASKA ALONG WITH AMPLE MOISTURE
SURGING NORTHWARD FROM EARLIER CONVECTION ACROSS SOUTHERN IA...HAS
LED TO MORE NUMEROUS SHRA/TSRA DEVELOPMENT ACROSS S MN. IT LOOKS
AS THOUGH THESE STORMS WERE ABLE TO TAP SOME ELEVATED INSTABILITY
ACROSS S MN DURING THE OVERNIGHT HRS. HOWEVER...THIS SHOULD BE
SHORT LIVED AS DEEPER MOISTURE WILL LIFT NORTHWARD ALLOWING FOR
MAINLY -DZ/FG TO PERSIST ACROSS S MN BEFORE DRIER AIR BEGINS TO
EVADE FROM THE CENTRAL PLAINS. THE DRIER AIR IS ALSO ANOTHER
PROBLEM AS THE FG/STRATUS HAS DEVELOPED AS FAR SOUTH AS KANSAS
WHICH MAY CONTINUE THE LOWER CLDS/FG IN S MN THEN PREVIOUS
FORECAST THAT HAD SOME SUNSHINE THIS AFTN. BIGGEST FACTOR FOR
CONTINUING FG/LOW CLDS THRU MIDDAY IS WHETHER THE DEPTH OF THE
STRATUS ACROSS NE/KS IS SHALLOW ENOUGH TO MIX OUT. WITH A MORE
PESSIMISTIC FORECAST ON CLD CVR...HAD LOWERED AFTN TEMPS A FEW
DEGREES. MAINLY FOLLOWING A SURGE OF HIGHER DEW PTS WHICH WILL
LEAD TO TEMPS IN THE 60S...WITH A FEW 70S ALONG THE IA BORDER.
AFT THE MORNING CONVECTION...MOST OF THE SHORT TERM FORECAST WILL
DEAL WITH THE STRONG SHRTWV/LONG WAVE TROUGH ACROSS THE WESTERN
U.S. AND HOW IT WILL TRANSLATE ACROSS THE PLAINS...AND INTO THE
UPPER MIDWEST BY MIDWEEK. MODELS ARE DEPICTING SEVERAL WEAK
SHRTWV/S RIDING NE ALONG A NEARLY STATIONARY FRONTAL BOUNDARY
LATER TONIGHT ACROSS EASTERN MN. ALONG AND AHEAD OF THIS
FRONT...VERY MILD AIR WILL LEAD TO ADDITIONAL CONVECTION...BUT
UNCERTAINTIES EXIST ON HOW WIDESPREAD THE ACTIVITY BECOMES IN THE
NEXT 24 HRS. WILL LEAN TOWARD ONLY CHC POPS THROUGH LATE
TONIGHT...BEFORE THE MAIN SHRTWV AND UPPER LEVEL SUPPORT SHOULD
INDUCE A LONG AREA OF PRECIPITATION ACROSS THE UPPER MIDWEST.
PRECIPITABLE WATER VALUES ARE OVER ONE INCH ALONG AND SOUTH OF
THIS FRONT...SO RAINFALL AMTS COULD BE LOCALLY HEAVY IN SC/EC MN
AS WELL AS WC WI ON WED/EARLY THU. ONCE THE MUCH COOLER AIR BEGINS
TO FILTER ACROSS THE UPPER MIDWEST...EXPECT RAINFALL AMTS TO
LESSEN...WITH THE CHC OF -SN IN WC MN EARLY THU MORNING BEFORE THE
PRECIPITATION ABRUPTLY ENDS BY MIDDAY. COOL -RA WILL OCCUR IN THE
EASTERN FA WHICH DEEPER MOISTURE WILL HOLD ON UNTIL THE LATE AFTN.
THE EXTENDED PERIOD REMAINS THE SAME WITH THE LARGE LONG WAVE
TROUGH DEVELOPING ACROSS THE U.S...MAINLY EAST OF THE ROCKIES.
THERE REMAINS SOME SUBTLE WAVES LATE IN THE WEEKEND...EARLY NEXT
WEEK ALONG THE TRANSITION ZONE OF MORE PACIFIC AIR MOVING ACROSS
THE ROCKIES. THIS MAY GENERATE A FEW RAIN OR SNOW SHOWERS
SUNDAY...AND POSSIBLE MONDAY. HOWEVER...BY MONDAY THE ATMOSPHERE
SHOULD BE WARM ENOUGH TO BE ALL IN THE FORM OF RAIN. ..JLT..
&&
.AVIATION.../06Z TAF ISSUANCE/
THINKING HAS NOT CHANGED MUCH FROM 00Z SET OF TAFS AND
ACCOMPANYING DISCUSSION. ONLY REAL CHANGE WAS FOR A SOMEWHAT
SLOWER INVASION OF LOWER CEILINGS AND VISIBILITIES... WHICH WAS
MENTIONED AS A POSSIBILITY. THINGS SEEM TO BE IN LINE WITH SREF
GUIDANCE AND LATEST NARRE-TL AS WELL. DIDN/T CHANGE PREVIOUS
FORECAST MUCH OTHER THAN TO PUSH BACK TIMING SOME... AND OTHERWISE
KEPT THINGS FAIRLY PESSIMISTIC THROUGH THE DAY AS VERY MOIST
PROFILE MOVES ACROSS THE AREA OVERNIGHT THROUGH MOST OF THE DAY ON
TUESDAY. IMPROVEMENT SHOULD OCCUR ON THE BACKSIDE OF UPPER WAVE
AND SURFACE IMPULSE LATE TOMORROW AFTERNOON AND TOMORROW
EVENING... SO DID ALLOW FOR RETURN OF VFR CONDITIONS DURING THAT
TIME FRAME.
KMSP...THERE IS DEFINITELY SOME UNCERTAINTY STILL ON THE TIMING OF
ARRIVAL AND DEPARTURE OF IFR AND LIFR CONDITIONS... AS WELL AS
EXACTLY HOW LOW CEILINGS AND VISIBILITIES WILL GET LATE TONIGHT
AND TUESDAY MORNING. STAYED CLOSE TO PREVIOUS FORECAST... WHICH IS
IN LINE WITH SOME OF THE UPSTREAM OBSERVATIONS AS WELL AS THE
TIME-HEIGHT FORECASTS FROM THE RAP AND NAM. HOWEVER... TIMING
COULD STILL VARY SEVERAL HOURS FROM INDICATED... PARTICULARLY WITH
THE IMPROVEMENT OF CONDITIONS ON TUESDAY.
/OUTLOOK FOR KMSP/
WEDNESDAY...IFR CEILINGS AND VISIBILITIES POSSIBLE... MVFR LIKELY.
WINDS NORTHEAST 5-10 KTS.
THURSDAY...IFR CEILINGS AND VISIBILITIES EXPECTED IN THE MORNING. WINDS
NORTHWEST 10-15 KTS.
FRIDAY...VFR CONDITIONS EXPECTED. WINDS NORTHWEST AROUND 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/TRH
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
638 PM CDT Wed Oct 24 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today through Saturday...
In the short term, the primary focus will be precipitation chances
with a dynamic cold front approaching from the northwest. Although
most model solutions continue to indicate light, warm sector
precipitation across northwest Missouri this afternoon and evening,
and low level moisture is evident in the scattered to broken MVFR
deck, the weak forcing resulting from slight isentropic lift has not
been enough to produce rain showers ahead of the surface cold front.
Short range hi-res models have caught onto the lack of precipitation
this afternoon, and keep rainfall out of Missouri prior to 06z. Have
hedged a bit earlier than the latest HRRR forecasts in bringing a
chance of precipitation into far northwestern portions of the CWA
for the potential that storms could develop on the boundary and move
into the far northwest before 06z; however, the better chances for
showers and thunderstorms will be Thursday as the main trough axis
dips into southeast Nebraska and begins driving the surface front
more quickly to the southeast.
Both the NAM and GFS produce convective precipitation along the low
level boundary tonight as frontogenesis increases and midlevel
cooling supports temporarily higher lapse rates, mainly above 925mb.
The best chance for any robust storms to develop will likely be
confined to the period between 06z-09z when storms can be rooted
more closely to the surface; afterward, the low-level inversion will
be compounded by surface frontal passage, and the focus for
precipitation will shift a bit closer to the 850mb front. Most
precipitation during the daylight hours on Thursday should occur
mainly along the 850 front, with a small chance for some isolated
development along the surface front in far eastern portions of the
forecast area early Thursday afternoon. Rain chances will linger a
bit across the southeast as midlevel forcing broadens early Friday
evening, with any remaining showers expected to move out shortly
between 00z-06z Friday.
Temperatures will drop significantly behind the cold front, and in
general, highs will be reached just prior to frontal passage on
Thursday. Highs for Friday and Saturday will be well below average
as cold surface high pressure settles into the region, and lows
Friday night could drop a few degrees below freezing across areas
that have not previously received a hard freeze.
Laflin
Medium Range (Saturday Night through Wednesday)...
As the Canadian surface ridge remains settled over the area this
weekend...temperatures will dip to around 30 degrees Sunday morning.
The northern zones have experienced a hard freeze so will have to
make some decisions tomorrow about headlines for the southern three
quarters of the area for Sunday and possibly Monday mornings. The
500-1000mb thicknesses are around 537-540DM by Sunday morning with
very light winds and clear skies.
Lows on Monday morning may be a few degrees warmer as the surface
ridge slides further east. Not much in the way of advection at this
time though and the dry conditions with light winds...may require a
downward tweak of the lows for Monday morning. By Tuesday...we will
see the winds finally swing around to the south as the ridge moves
further east so there will be an increase in the thicknesses and 850
mb temps...therefore we should see above freezing temperatures on
Tuesday and Wednesday mornings.
Daytime highs through the extended will show a gradual warming trend
as well from the 40s on Sunday to the around 60 degrees F by Tuesday
and Wednesday.
Storm track remains well to the north so no precipitation is
expected through the period. Adolphson
&&
.AVIATION...
For the 00Z TAFS...short term concerns for the next 12 hours are
gusty southerly winds ahead of a cold front currently over southeast
Nebraska. Expect these winds to remain somewhat gusty overnight
similar to what we saw last night. In the meantime 2000 foot winds
will increase to 50-55 kts out of the southwest through 06Z. This
could certainly cause some minor LLWS concerns for small aircraft,
but given the gusty surface winds, this will be more of a low-level
turbulence concern vs. rapid changes in wind speed/direction so opted
to keep LLWS out of the TAF.
Front will slide through the area early Thursday morning, and may be
accompanied by some showers and thunderstorms near and behind the
front. This activity will likely fire up over southern Nebraska late
this evening and decrease in coverage as it approaches the KC area
early Thursday, so will continue with only VCTS wording for now.
Sharp low-level inversion and thick low-level moisture behind the
front are likely to allow IFR cigs to continue spreading southeast
into the KC area following frontal passage. Wouldn`t be surprised if
IFR/MVFR stick around several hours on Thursday, possibly longer
than models are suggesting.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1251 PM CDT TUE OCT 23 2012
.SHORT TERM...
ISSUED AT 214 AM CDT TUE OCT 23 2012
(TODAY AND TONIGHT)
FOCUS WILL ONCE AGAIN BE TSRA CHANCES TODAY...TURNING TO TEMPS ONCE
PRECIP HAS ENDED.
ONGOING TSRA JUST W OF THE CWA IS ANTICIPATED TO CONTINUE TO MOVE
ENE THRU THE CWA TODAY. THE 23/04Z HRRR AND 23/00Z 4KM NCEP WRF ARE
IN GOOD AGREEMENT AND HANDLE THE ONGOING SITUATION RATHER WELL. PLAN
IS TO CLOSELY FOLLOW THESE MDLS FOR POPS TODAY...PROVIDED THIS TREND
CONTINUES. THESE MDLS...AS WELL AS THE OPERATIONAL MDLS...ARE IN
GOOD AGREEMENT WITH PRECIP ENDING BY EARLY AFTERNOON AT THE LATEST
AS THE S/W WILL BE NEARING THE IL/IN BOARDER BY 21Z.
WITH PRECIP COMING TO AN END AND CLOUDS CLEARING THRU THE
AFTERNOON...AMPLE INSOLATION SHUD BE AVAILABLE FOR A QUICK WARM UP
TODAY. MADE ONLY MINOR CHANGES TO THE GOING FORECAST FOR TEMPS TODAY
AND TONIGHT. RAISED TEMPS A COUPLE OF DEGREES ACROSS CNTL MO AS
850MB TEMPS SHUD BE NEARING 18C ACCORDING TO THE NAM. WHILE THIS IS
A WARM OUTLIER AMONG THE 00Z GUIDANCE...THIS SOLN SEEMS PROBABLE
GIVEN THE WARM 850MB TEMPS ADVECTING NEWD BEHIND THIS S/W. THAT
SAID...MDL SOUNDINGS FOR TODAY SUGGEST MUCH OF THE REGION WILL NOT
MIX TO 850MB AND HAVE THEREFORE TRENDED TWD THE WARMER
GUIDANCE...BUT REMAINED JUST UNDER ACROSS CNTL MO. SIMILAR TRENDS
CONTINUE TONIGHT WITH SLY TO SWLY WINDS WILL REMAIN AOA 7 KTS.
TILLY
&&
.LONG TERM...
ISSUED AT 349 AM CDT TUE OCT 23 2012
(WEDNESDAY THROUGH THURSDAY)
ONCE THE S/W RESPONSIBLE FOR THE ONGOING TSRA MOVES E OF THE
AREA...THE SHORT TERM IS EXPECTED TO REMAIN DRY UNTIL THURS. MDLS
ARE IN RELATIVELY GOOD AGREEMENT UNTIL WED NIGHT. THE GFS SUGGESTS A
REINFORCING S/W ROUNDING THE BASE OF THE UPPER LOW WHICH HELPS TO
SPEED UP FROPA THURS NIGHT. HAVE TRENDED TWD THE CONSENSUS OF THE
OTHER MDLS...BUT KEPT CHANCE POPS TO ACCOUNT FOR THE FASTER GFS
SOLN.
UNTIL THURS...FOCUS REMAINS TEMPS. NOT MUCH HAS CHANGED WITH THE
23/00Z GUIDANCE AND SAW NO REASON TO MAKE MANY CHANGES TO THE GOING
FORECAST. OVERALL...CONTINUED TREND GOING AOA WARMEST GUIDANCE.
(FRIDAY THROUGH MONDAY)
MDL TRENDS DO NOT CHANGE MUCH EARLY IN THE EXTD PERIOD. THE 22/18Z
DGEX DEVELOPS AN AMPLIFIED TROF WITH THE SYSTEM AFFECTING THE CWA AT
THE BEGINNING OF THE PERIOD AND CONTINUES TO DEEPEN THIS TROF THRU
THE WEEKEND. THIS SOLN IS AN OUTLIER AMONG THE OPERATIONAL
MDLS...EVEN AMONG THE GEFS...AND HAVE TRENDED TWD THE OTHER
OPERATIONAL MDLS THRU THE PERIOD.
THE GEM BEGINS TO SPEED UP TO COME INTO BETTER AGREEMENT WITH THE
GFS LATE FRI INTO SAT. HAVE THEREFORE TRENDED TWD THESE SOLNS
REGARDING POPS LOWERING POPS FRI NIGHT ACROSS NWRN PORTIONS OF THE
CWA AND KEPT SAT DRY. REMAINDER OF THE EXTD IS DRY FOR NOW...BUT
MDLS SUGGEST A COUPLE OF S/WS THAT MAY BRING PRECIP ACROSS NRN
PORTIONS OF THE CWA LATE IN THE EXTD PERIOD.
AS FOR TEMPS...MDLS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE
PERIOD...LARGE DIFFERENCES BEGIN BY SUN AND PROVIDE A VARIETY OF
SOLNS THRU THE PERIOD. HAVE TRENDED TWD A COMPROMISE OF THE
GFS/ECMWF/GEM FOR FRI. WITH UNCERTAINTY GROWING THRU THE EXTD...HAVE
TRENDED TWD A BLEND OF THE GFS/ECMWF BEYOND FRI AS THESE SOLNS
REMAIN SOMEWHAT CLOSE.
TILLY
&&
.AVIATION...
ISSUED AT 1245 PM CDT TUE OCT 23 2012
MAIN AREA OF SHOWERS AND THUNDERSTORMS WEAKENING AND MOVING AWAY
FROM TAF SITES. SO MAIN ISSUE WILL BE THE CLOUDS THROUGH THE
FORECAST PERIOD. VFR/HIGH END MVFR CIGS TO SCATTER OUT THIS
AFTERNOON...WITH WINDS PICKING UP A BIT FROM THE SOUTH WITH GUSTS
TO NEAR 20 KTS AT TIMES. WINDS TO DIMINISH TOWARDS SUNSET...THEN
PICK BACK UP AGAIN BY MID MORNING ON WEDNESDAY AS WINDS MIX DOWN
TO SURFACE AND DIURNAL CU POP UP.
SPECIFICS FOR KSTL...MAIN AREA OF SHOWERS AND THUNDERSTORMS WEAKENING
AND MOVING AWAY FROM METRO AREA. SO MAIN ISSUE WILL BE THE CLOUDS
THROUGH THE FORECAST PERIOD. VFR CIGS TO SCATTER OUT THIS
AFTERNOON...WITH WINDS PICKING UP A BIT FROM THE SOUTH WITH GUSTS
TO NEAR 20 KTS AT TIMES. WINDS TO DIMINISH TOWARDS SUNSET...THEN
PICK BACK UP AGAIN BY MID MORNING ON WEDNESDAY AS WINDS MIX DOWN
TO SURFACE AND DIURNAL CU POP UP.
BYRD
&&
.CLIMATE...
ISSUED AT 319 PM CDT SUN OCT 21 2012
RECORD HIGHS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 86(1939) 91(1939) 86(1939)
OCTOBER 24 85(1940) 86(1940) 84(1940)
RECORD HIGH MINIMUMS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 67(2010) 65(1963) 63(1991)
OCTOBER 24 66(1991) 65(1991) 65(1991)
OCTOBER 25 69(1939) 68(1939) 63(1963)
MILLER
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
647 AM CDT TUE OCT 23 2012
.SHORT TERM...
ISSUED AT 214 AM CDT TUE OCT 23 2012
(TODAY AND TONIGHT)
FOCUS WILL ONCE AGAIN BE TSRA CHANCES TODAY...TURNING TO TEMPS ONCE
PRECIP HAS ENDED.
ONGOING TSRA JUST W OF THE CWA IS ANTICIPATED TO CONTINUE TO MOVE
ENE THRU THE CWA TODAY. THE 23/04Z HRRR AND 23/00Z 4KM NCEP WRF ARE
IN GOOD AGREEMENT AND HANDLE THE ONGOING SITUATION RATHER WELL. PLAN
IS TO CLOSELY FOLLOW THESE MDLS FOR POPS TODAY...PROVIDED THIS TREND
CONTINUES. THESE MDLS...AS WELL AS THE OPERATIONAL MDLS...ARE IN
GOOD AGREEMENT WITH PRECIP ENDING BY EARLY AFTERNOON AT THE LATEST
AS THE S/W WILL BE NEARING THE IL/IN BOARDER BY 21Z.
WITH PRECIP COMING TO AN END AND CLOUDS CLEARING THRU THE
AFTERNOON...AMPLE INSOLATION SHUD BE AVAILABLE FOR A QUICK WARM UP
TODAY. MADE ONLY MINOR CHANGES TO THE GOING FORECAST FOR TEMPS TODAY
AND TONIGHT. RAISED TEMPS A COUPLE OF DEGREES ACROSS CNTL MO AS
850MB TEMPS SHUD BE NEARING 18C ACCORDING TO THE NAM. WHILE THIS IS
A WARM OUTLIER AMONG THE 00Z GUIDANCE...THIS SOLN SEEMS PROBABLE
GIVEN THE WARM 850MB TEMPS ADVECTING NEWD BEHIND THIS S/W. THAT
SAID...MDL SOUNDINGS FOR TODAY SUGGEST MUCH OF THE REGION WILL NOT
MIX TO 850MB AND HAVE THEREFORE TRENDED TWD THE WARMER
GUIDANCE...BUT REMAINED JUST UNDER ACROSS CNTL MO. SIMILAR TRENDS
CONTINUE TONIGHT WITH SLY TO SWLY WINDS WILL REMAIN AOA 7 KTS.
TILLY
&&
.LONG TERM...
ISSUED AT 349 AM CDT TUE OCT 23 2012
(WEDNESDAY THROUGH THURSDAY)
ONCE THE S/W RESPONSIBLE FOR THE ONGOING TSRA MOVES E OF THE
AREA...THE SHORT TERM IS EXPECTED TO REMAIN DRY UNTIL THURS. MDLS
ARE IN RELATIVELY GOOD AGREEMENT UNTIL WED NIGHT. THE GFS SUGGESTS A
REINFORCING S/W ROUNDING THE BASE OF THE UPPER LOW WHICH HELPS TO
SPEED UP FROPA THURS NIGHT. HAVE TRENDED TWD THE CONSENSUS OF THE
OTHER MDLS...BUT KEPT CHANCE POPS TO ACCOUNT FOR THE FASTER GFS
SOLN.
UNTIL THURS...FOCUS REMAINS TEMPS. NOT MUCH HAS CHANGED WITH THE
23/00Z GUIDANCE AND SAW NO REASON TO MAKE MANY CHANGES TO THE GOING
FORECAST. OVERALL...CONTINUED TREND GOING AOA WARMEST GUIDANCE.
(FRIDAY THROUGH MONDAY)
MDL TRENDS DO NOT CHANGE MUCH EARLY IN THE EXTD PERIOD. THE 22/18Z
DGEX DEVELOPS AN AMPLIFIED TROF WITH THE SYSTEM AFFECTING THE CWA AT
THE BEGINNING OF THE PERIOD AND CONTINUES TO DEEPEN THIS TROF THRU
THE WEEKEND. THIS SOLN IS AN OUTLIER AMONG THE OPERATIONAL
MDLS...EVEN AMONG THE GEFS...AND HAVE TRENDED TWD THE OTHER
OPERATIONAL MDLS THRU THE PERIOD.
THE GEM BEGINS TO SPEED UP TO COME INTO BETTER AGREEMENT WITH THE
GFS LATE FRI INTO SAT. HAVE THEREFORE TRENDED TWD THESE SOLNS
REGARDING POPS LOWERING POPS FRI NIGHT ACROSS NWRN PORTIONS OF THE
CWA AND KEPT SAT DRY. REMAINDER OF THE EXTD IS DRY FOR NOW...BUT
MDLS SUGGEST A COUPLE OF S/WS THAT MAY BRING PRECIP ACROSS NRN
PORTIONS OF THE CWA LATE IN THE EXTD PERIOD.
AS FOR TEMPS...MDLS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE
PERIOD...LARGE DIFFERENCES BEGIN BY SUN AND PROVIDE A VARIETY OF
SOLNS THRU THE PERIOD. HAVE TRENDED TWD A COMPROMISE OF THE
GFS/ECMWF/GEM FOR FRI. WITH UNCERTAINTY GROWING THRU THE EXTD...HAVE
TRENDED TWD A BLEND OF THE GFS/ECMWF BEYOND FRI AS THESE SOLNS
REMAIN SOMEWHAT CLOSE.
TILLY
&&
.AVIATION...
ISSUED AT 628 AM CDT TUE OCT 23 2012
A LARGE AREA OF RAIN WITH SOME EMBEDDED THUNDERSTORMS OVER CENTRAL
AND EASTERN MO WILL CONTINUE TO PROGRESS EASTWARD AND IMPACT THE
TAFS SITES DURING THE MORNING HOURS. OBSERVATIONS DURING THE
OVERNIGHT HOURS WITHIN THE RAIN AREA SUGGESTS MUCH OF THE RAIN
WILL OCCUR WITH VFR CONDITIONS OCCASIONALLY LOWERING TO MVFR WITH
SOME OF THE EMBEDDED THUNDER. ENDING OF THE PRECIPITATION IS A
LITTLE UNCERTAIN. THERE CONTINUE TO BE NEW CELLS DEVELOPING IN
WEST CENTRAL MO ON THE BACK EDGE. AT THIS TIME I HAVE ENDED
PRECITATION AT KUIN AND THE ST LOUIS AREA TAF SITES AT 16Z BUT IT
COULD BE A LITTLE LATER. AFTER THE PRECIPATION ENDS...VFR
CONDITIONS SHOULD PREVIAL WITH DECREASING CLOUDS.
SPECIFICS FOR KSTL...
LIGHT RAIN SHOULD BEGIN WITH THE NEXT HOUR AND CONTINUE THROUGH
LATE MORNING. UPSTREAM OBSERVATIONS OVERNIGHT SUGGESTS MUCH OF
THE RAIN WILL OCCUR WITH VFR CONDITIONS OCCASIONALLY LOWERING TO
MVFR WITH SOME OF THE EMBEDDED THUNDER. ENDING OF THE PRECIPITATION
IS A LITTLE UNCERTAIN. AT THIS TIME I HAVE ENDED PRECITATION AT
16Z BUT IT COULD BE A LITTLE LATER. AFTER THE PRECIPATION
ENDS...VFR CONDITIONS SHOULD PREVIAL WITH DECREASING CLOUDS.
GLASS
&&
.CLIMATE...
ISSUED AT 319 PM CDT SUN OCT 21 2012
RECORD HIGHS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 86(1939) 91(1939) 86(1939)
OCTOBER 24 85(1940) 86(1940) 84(1940)
RECORD HIGH MINIMUMS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 67(2010) 65(1963) 63(1991)
OCTOBER 24 66(1991) 65(1991) 65(1991)
OCTOBER 25 69(1939) 68(1939) 63(1963)
MILLER
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 83 63 86 66 / 80 5 0 10
QUINCY 83 62 83 64 / 60 10 5 10
COLUMBIA 86 64 86 65 / 60 10 0 10
JEFFERSON CITY 86 64 86 65 / 70 10 0 10
SALEM 80 62 83 62 / 80 5 0 5
FARMINGTON 82 59 83 59 / 80 5 0 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
349 AM CDT TUE OCT 23 2012
.SHORT TERM...
ISSUED AT 214 AM CDT TUE OCT 23 2012
(TODAY AND TONIGHT)
FOCUS WILL ONCE AGAIN BE TSRA CHANCES TODAY...TURNING TO TEMPS ONCE
PRECIP HAS ENDED.
ONGOING TSRA JUST W OF THE CWA IS ANTICIPATED TO CONTINUE TO MOVE
ENE THRU THE CWA TODAY. THE 23/04Z HRRR AND 23/00Z 4KM NCEP WRF ARE
IN GOOD AGREEMENT AND HANDLE THE ONGOING SITUATION RATHER WELL. PLAN
IS TO CLOSELY FOLLOW THESE MDLS FOR POPS TODAY...PROVIDED THIS TREND
CONTINUES. THESE MDLS...AS WELL AS THE OPERATIONAL MDLS...ARE IN
GOOD AGREEMENT WITH PRECIP ENDING BY EARLY AFTERNOON AT THE LATEST
AS THE S/W WILL BE NEARING THE IL/IN BOARDER BY 21Z.
WITH PRECIP COMING TO AN END AND CLOUDS CLEARING THRU THE
AFTERNOON...AMPLE INSOLATION SHUD BE AVAILABLE FOR A QUICK WARM UP
TODAY. MADE ONLY MINOR CHANGES TO THE GOING FORECAST FOR TEMPS TODAY
AND TONIGHT. RAISED TEMPS A COUPLE OF DEGREES ACROSS CNTL MO AS
850MB TEMPS SHUD BE NEARING 18C ACCORDING TO THE NAM. WHILE THIS IS
A WARM OUTLIER AMONG THE 00Z GUIDANCE...THIS SOLN SEEMS PROBABLE
GIVEN THE WARM 850MB TEMPS ADVECTING NEWD BEHIND THIS S/W. THAT
SAID...MDL SOUNDINGS FOR TODAY SUGGEST MUCH OF THE REGION WILL NOT
MIX TO 850MB AND HAVE THEREFORE TRENDED TWD THE WARMER
GUIDANCE...BUT REMAINED JUST UNDER ACROSS CNTL MO. SIMILAR TRENDS
CONTINUE TONIGHT WITH SLY TO SWLY WINDS WILL REMAIN AOA 7 KTS.
TILLY
&&
.LONG TERM...
ISSUED AT 349 AM CDT TUE OCT 23 2012
(WEDNESDAY THROUGH THURSDAY)
ONCE THE S/W RESPONSIBLE FOR THE ONGOING TSRA MOVES E OF THE
AREA...THE SHORT TERM IS EXPECTED TO REMAIN DRY UNTIL THURS. MDLS
ARE IN RELATIVELY GOOD AGREEMENT UNTIL WED NIGHT. THE GFS SUGGESTS A
REINFORCING S/W ROUNDING THE BASE OF THE UPPER LOW WHICH HELPS TO
SPEED UP FROPA THURS NIGHT. HAVE TRENDED TWD THE CONSENSUS OF THE
OTHER MDLS...BUT KEPT CHANCE POPS TO ACCOUNT FOR THE FASTER GFS
SOLN.
UNTIL THURS...FOCUS REMAINS TEMPS. NOT MUCH HAS CHANGED WITH THE
23/00Z GUIDANCE AND SAW NO REASON TO MAKE MANY CHANGES TO THE GOING
FORECAST. OVERALL...CONTINUED TREND GOING AOA WARMEST GUIDANCE.
(FRIDAY THROUGH MONDAY)
MDL TRENDS DO NOT CHANGE MUCH EARLY IN THE EXTD PERIOD. THE 22/18Z
DGEX DEVELOPS AN AMPLIFIED TROF WITH THE SYSTEM AFFECTING THE CWA AT
THE BEGINNING OF THE PERIOD AND CONTINUES TO DEEPEN THIS TROF THRU
THE WEEKEND. THIS SOLN IS AN OUTLIER AMONG THE OPERATIONAL
MDLS...EVEN AMONG THE GEFS...AND HAVE TRENDED TWD THE OTHER
OPERATIONAL MDLS THRU THE PERIOD.
THE GEM BEGINS TO SPEED UP TO COME INTO BETTER AGREEMENT WITH THE
GFS LATE FRI INTO SAT. HAVE THEREFORE TRENDED TWD THESE SOLNS
REGARDING POPS LOWERING POPS FRI NIGHT ACROSS NWRN PORTIONS OF THE
CWA AND KEPT SAT DRY. REMAINDER OF THE EXTD IS DRY FOR NOW...BUT
MDLS SUGGEST A COUPLE OF S/WS THAT MAY BRING PRECIP ACROSS NRN
PORTIONS OF THE CWA LATE IN THE EXTD PERIOD.
AS FOR TEMPS...MDLS ARE IN RELATIVELY GOOD AGREEMENT EARLY IN THE
PERIOD...LARGE DIFFERENCES BEGIN BY SUN AND PROVIDE A VARIETY OF
SOLNS THRU THE PERIOD. HAVE TRENDED TWD A COMPROMISE OF THE
GFS/ECMWF/GEM FOR FRI. WITH UNCERTAINTY GROWING THRU THE EXTD...HAVE
TRENDED TWD A BLEND OF THE GFS/ECMWF BEYOND FRI AS THESE SOLNS
REMAIN SOMEWHAT CLOSE.
TILLY
&&
.AVIATION...
ISSUED AT 1057 PM CDT MON OCT 22 2012
AN INITIAL BATCH OF SCATTERED SHOWERS WAS MOVING NEWD THROUGH COU
LATE THIS EVNG. A BETTER COVERAGE OF SHOWERS AND STORMS IS
EXPECTED LATE TGT AND TUE MRNG AHEAD OF A SHORTWAVE TROUGH NOW
OVER ERN PORTIONS OF KS AND OK WHICH WILL MOVE E-NEWD THROUGH MO
LATE TGT AND TUE MRNG. AN AREA OF SHOWERS AND THUNDERSTORMS MOVING
NEWD THROUGH SWRN MO SHOULD MOVE THROUGH OUR AREA LATE TGT AND
EARLY TUE MRNG. WILL INCLUDE VCTS IN THE TAFS AND A TEMPO GROUP OF
SHOWERS DURING THIS TIME PERIOD. THERE WILL BE PLENTY OF LOW-MID
LEVEL CLOUDS LATE TGT AND TUE MRNG BUT THIS SHOULD BE VFR OUTSIDE
OF SHOWERS/STORMS. SLY SFC WINDS WILL CONTINUE THIS FORECAST
PERIOD AS THE WARM FRONT HAS MOVED N OF THE TAF SITES. THERE MAY
BE SOME LLWS LATE TGT AND EARLY TUE MRNG BUT IT DOES NOT APPEAR
STRONG ENOUGH TO INCLUDE IN THE TAFS WITH THE SWLY LOW LEVEL JET
TRANSLATING NEWD THROUGH OR NEAR COU AND UIN LATE TGT AND EARLY
TUE MRNG. THE CLOUDS SHOULD SCATTER OUT TUE AFTN INTO TUE EVNG
WITH THE WARM FRONT WELL N OF OUR AREA AND THE SHORTWAVE E OF THE
REGION.
SPECIFICS FOR KSTL...THE SHOWERS AND STORMS ACROSS SWRN MO SHOULD
MOVE NEWD UP THE I-44 CORRIDOR AND INTO STL LATE TGT BY 08-09Z TUE.
WILL INCLUDE VCTS ALONG WITH A TEMPO GROUP OF SHOWERS AFTER THIS TIME.
THE SHOWERS AND STORMS SHOULD MOVE NE OF STL BY LATE TUE MRNG.
VFR LOW-MID LEVEL CLOUD CEILING SHOULD PREVAIL LATE TGT AND TUE
MRNG...THEN THE CLOUDS SHOULD SCATTER OUT TUE AFTN OR EARLY TUE
EVNG. SLY SFC WIND WILL CONTINUE LATE TGT AND INCREASE TO AROUND
13-14 KTS TUE AFTN...THEN WEAKEN TUE EVNG.
GKS
&&
.CLIMATE...
ISSUED AT 319 PM CDT SUN OCT 21 2012
RECORD HIGHS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 86(1939) 91(1939) 86(1939)
OCTOBER 24 85(1940) 86(1940) 84(1940)
RECORD HIGH MINIMUMS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 67(2010) 65(1963) 63(1991)
OCTOBER 24 66(1991) 65(1991) 65(1991)
OCTOBER 25 69(1939) 68(1939) 63(1963)
MILLER
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 83 63 86 66 / 80 5 0 10
QUINCY 83 62 83 64 / 60 10 5 10
COLUMBIA 86 64 86 65 / 60 10 0 10
JEFFERSON CITY 86 64 86 65 / 70 10 0 10
SALEM 80 62 83 62 / 80 5 0 5
FARMINGTON 82 59 83 59 / 80 5 0 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
215 AM CDT TUE OCT 23 2012
.SHORT TERM...
ISSUED AT 214 AM CDT TUE OCT 23 2012
(TODAY AND TONIGHT)
FOCUS WILL ONCE AGAIN BE TSRA CHANCES TODAY...TURNING TO TEMPS ONCE
PRECIP HAS ENDED.
ONGOING TSRA JUST W OF THE CWA IS ANTICIPATED TO CONTINUE TO MOVE
ENE THRU THE CWA TODAY. THE 23/04Z HRRR AND 23/00Z 4KM NCEP WRF ARE
IN GOOD AGREEMENT AND HANDLE THE ONGOING SITUATION RATHER WELL. PLAN
IS TO CLOSELY FOLLOW THESE MDLS FOR POPS TODAY...PROVIDED THIS TREND
CONTINUES. THESE MDLS...AS WELL AS THE OPERATIONAL MDLS...ARE IN
GOOD AGREEMENT WITH PRECIP ENDING BY EARLY AFTERNOON AT THE LATEST
AS THE S/W WILL BE NEARING THE IL/IN BOARDER BY 21Z.
WITH PRECIP COMING TO AN END AND CLOUDS CLEARING THRU THE
AFTERNOON...AMPLE INSOLATION SHUD BE AVAILABLE FOR A QUICK WARM UP
TODAY. MADE ONLY MINOR CHANGES TO THE GOING FORECAST FOR TEMPS TODAY
AND TONIGHT. RAISED TEMPS A COUPLE OF DEGREES ACROSS CNTL MO AS
850MB TEMPS SHUD BE NEARING 18C ACCORDING TO THE NAM. WHILE THIS IS
A WARM OUTLIER AMONG THE 00Z GUIDANCE...THIS SOLN SEEMS PROBABLE
GIVEN THE WARM 850MB TEMPS ADVECTING NEWD BEHIND THIS S/W. THAT
SAID...MDL SOUNDINGS FOR TODAY SUGGEST MUCH OF THE REGION WILL NOT
MIX TO 850MB AND HAVE THEREFORE TRENDED TWD THE WARMER
GUIDANCE...BUT REMAINED JUST UNDER ACROSS CNTL MO. SIMILAR TRENDS
CONTINUE TONIGHT WITH SLY TO SWLY WINDS WILL REMAIN AOA 7 KTS.
TILLY
&&
.LONG TERM...
ISSUED AT 324 PM CDT MON OCT 22 2012
(TUESDAY THROUGH WEDNESDAY)
CURRENT WV IMAGERY DEPICTS SHORTWAVE TROUGH OVER WESTERN OKLAHOMA. THIS
TROUGH AND ASSOCIATED VORTICITY MAXIMA WILL TRANSLATE ACROSS THE MIDDLE
OF THE CWFA EARLY TOMORROW AND WEAKEN WITH TIME. VERTICAL FORCING FOR ASCENT
WILL INCREASE IMMEDIATELY AHEAD OF THIS FEATURE DUE TO DCPVA. IN ADDITION...
LL FORCING VIA WAA/MOISTURE TRANSPORT VIA A 35-KT LLJ WILL ALSO HELP
SUPPORT LL CONVERGENCE/ASCENT FOR SHOWERS AND THUNDERSTORMS EARLY TOMORROW...
ESPECIALLY FROM MISSISSIPPI RIVER EAST. WENT HIGH CHANCE POPS FOR 12-18 UTC
TOMORROW IN THIS GENERAL AREA BUT DID NOT GO HIGHER DUE TO EXPECTED WEAKER
FORCING AT LOW LEVELS COMPARED TO TODAY AND UNCERTAINTY ON FAVORED REGION
FOR DEVELOPMENT. PRECIPITATION CHANCES SHOULD DIMINISH BY EARLY AFTERNOON...
THOUGH CONFIDENCE IN THIS IS NOT AS HIGH AS IT OTHERWISE WOULD BE AFTER
OBSERVING PRECIPITATION STILL ONGOING AS OF 2000 UTC TODAY WITH CONTINUED
WARM/MOIST ADVECTION.
TEMPERATURES TUESDAY AND WEDNESDAY WILL LIKELY BE VERY WARM...SOME
20 DEGREES ABOVE NORMAL. SOME CONCERN WITH TUESDAYS HIGHS BEING TOO
WARM IF CLOUDS/PRECIP LINGER LONGER THAN EXPECTED LIKE THEY DID TODAY. IN
ADDITION...SOME WEAK CAA/NEUTRAL ADVECTION BEHIND SHORTWAVE TROUGH MAY KEEP
TEMPS A FEW DEGREES COOLER ON TUEDAY. FOR WEDNESDAY...DEEPER MIXING AND
LOW/MIDLEVEL TEMPS AT LEAST AS WARM AS TUESDAY SHOULD SUPPORT HIGHS IN MID
80S AREAWIDE...WHICH IS AOA WARMER MAV GUIDANCE AND NEAR OR ABOVE RECORD
VALUES FOR THE DATE. FOR MORE INFORMATION...PLEASE SEE CLIMO SECTION BELOW.
(THURSDAY THROUGH MONDAY)
A FAILRY POTENT COLD FRONT ATTENDANT FROM A SFC LOW TRAVELLING ACROSS
WI AND INTO CANADA WILL INCREASE CHANCES OF SHOWERS AND STORMS FROM
NW TO SE ACROSS THE AREA ON THURSDAY. WENT WITH A GFS/ECMWF BLEND REGARDING
FRONTAL PLACEMENT AND ASSOCIATED WEATHER ELEMENTS. FRONT LOOKS TO BE NEAR
KCOU-KUIN LINE BY 1800 UTC THURSDAY AND APRPOACHING KUNO-KSTL LINE BY 0000
UTC FRIDAY. WITH MOST OF AREA AHEAD OF FRONT FOR AT LEAST A GOOD PART OF THE
DAY...WENT AOA MEX GUIDANCE FOR HIGH TEMPERATURES.
SHOWERS AND STORMS LOOK TO BE ALONG/JUST AHEAD OF THE FRONT WITH
POST-FRONTAL...MORE STRATIFORM PRECIPITATION BEHIND FRONT IN PRESENCE OF
FRONTOGENETICAL FORCING. STILL LOOKS LIKE THERE IS AT LEAST SOME POTENTIAL
FOR SOME SEVERE STORMS WITH THE FRONT AS 30-50 KNOTS OF DEEP LAYER SHEAR
AND STEEP MIDLEVEL LAPSE RATES WILL EXIST. HOWEVER...FAIRLY WEAK SFC
CONVERGENCE ALONG FRONT AND ONLY MARGINAL INSTABILITY (500-1000 J/KG SBCAPE)
LOOK TO PRECLUDE A HIGHER THREAT AT THIS TIME.
BEHIND THE FRONT...MUCH COOLER TEMPERATUERS WILL BE IN THE OFFING WITH
HIGHS ONLY IN L/M 50S THROUGH THE WEEKEND. STILL QUITE A BIT OF UNCERTAINTY
FOR SUNDAY-MONDAY AS GFS/ECMWF HAVE FLIP-FLOPPED A FEW TIMES REGARDING
HOW DEEP THE TROUGH WILL BE CARVING OUT IN THE EASTERN THIRD OF THE COUNTRY
AND ITS POTENTIAL INTERACTION WITH WHAT IS NOW NAMED TROPICAL DEPRESSION 18
OUT IN CARIBBEAN SEA. TEMPERATURES MAY REBOUND A BIT FASTER THAN CURRENTLY
FORECAST IF FLOW IS MORE ZONAL ACROSS OUR REGION ALLOWING COLDER AIR TO STAY
FURTHER TO THE NORTH.
GOSSELIN
&&
.AVIATION...
ISSUED AT 1057 PM CDT MON OCT 22 2012
AN INITIAL BATCH OF SCATTERED SHOWERS WAS MOVING NEWD THROUGH COU
LATE THIS EVNG. A BETTER COVERAGE OF SHOWERS AND STORMS IS
EXPECTED LATE TGT AND TUE MRNG AHEAD OF A SHORTWAVE TROUGH NOW
OVER ERN PORTIONS OF KS AND OK WHICH WILL MOVE E-NEWD THROUGH MO
LATE TGT AND TUE MRNG. AN AREA OF SHOWERS AND THUNDERSTORMS MOVING
NEWD THROUGH SWRN MO SHOULD MOVE THROUGH OUR AREA LATE TGT AND
EARLY TUE MRNG. WILL INCLUDE VCTS IN THE TAFS AND A TEMPO GROUP OF
SHOWERS DURING THIS TIME PERIOD. THERE WILL BE PLENTY OF LOW-MID
LEVEL CLOUDS LATE TGT AND TUE MRNG BUT THIS SHOULD BE VFR OUTSIDE
OF SHOWERS/STORMS. SLY SFC WINDS WILL CONTINUE THIS FORECAST
PERIOD AS THE WARM FRONT HAS MOVED N OF THE TAF SITES. THERE MAY
BE SOME LLWS LATE TGT AND EARLY TUE MRNG BUT IT DOES NOT APPEAR
STRONG ENOUGH TO INCLUDE IN THE TAFS WITH THE SWLY LOW LEVEL JET
TRANSLATING NEWD THROUGH OR NEAR COU AND UIN LATE TGT AND EARLY
TUE MRNG. THE CLOUDS SHOULD SCATTER OUT TUE AFTN INTO TUE EVNG
WITH THE WARM FRONT WELL N OF OUR AREA AND THE SHORTWAVE E OF THE
REGION.
SPECIFICS FOR KSTL...THE SHOWERS AND STORMS ACROSS SWRN MO SHOULD
MOVE NEWD UP THE I-44 CORRIDOR AND INTO STL LATE TGT BY 08-09Z TUE.
WILL INCLUDE VCTS ALONG WITH A TEMPO GROUP OF SHOWERS AFTER THIS TIME.
THE SHOWERS AND STORMS SHOULD MOVE NE OF STL BY LATE TUE MRNG.
VFR LOW-MID LEVEL CLOUD CEILING SHOULD PREVAIL LATE TGT AND TUE
MRNG...THEN THE CLOUDS SHOULD SCATTER OUT TUE AFTN OR EARLY TUE
EVNG. SLY SFC WIND WILL CONTINUE LATE TGT AND INCREASE TO AROUND
13-14 KTS TUE AFTN...THEN WEAKEN TUE EVNG.
GKS
&&
.CLIMATE...
ISSUED AT 319 PM CDT SUN OCT 21 2012
RECORD HIGHS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 86(1939) 91(1939) 86(1939)
OCTOBER 24 85(1940) 86(1940) 84(1940)
RECORD HIGH MINIMUMS
DATE ST. LOUIS COLUMBIA QUINCY
----------------------------------------------
OCTOBER 23 67(2010) 65(1963) 63(1991)
OCTOBER 24 66(1991) 65(1991) 65(1991)
OCTOBER 25 69(1939) 68(1939) 63(1963)
MILLER
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 83 63 86 66 / 60 5 0 10
QUINCY 83 62 83 64 / 20 10 5 10
COLUMBIA 86 64 86 65 / 20 10 0 10
JEFFERSON CITY 86 64 86 65 / 20 10 0 10
SALEM 80 62 83 62 / 60 5 0 5
FARMINGTON 82 59 83 59 / 60 5 0 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
128 PM CDT TUE OCT 23 2012
.AVIATION...SKIES HAVE CLEARED AT BOTH THE KLBF AND KVTN TAF
SITES...AND SKIES SHOULD SLOWLY CLEAR EAST OF A LINE FROM KANW TO
KBBW THROUGH THE AFTERNOON. UNTIL SKIES CLEAR...WIDESPREAD IFR
CEILINGS WILL PREVAIL. A COLD FRONT WILL DROP INTO THE AREA
TONIGHT. A NARROW BAND OF MVFR/IFR CEILINGS MAY DEVELOP AFTER 09Z
BEHIND THE FRONT ACROSS CENTRAL AND SOUTHWEST NEBRASKA.
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT TUE OCT 23 2012/
DISCUSSION...
PRIMARY FOCUS THROUGH THIS FORECAST PERIOD IS FOG AND TEMPERATURES
TODAY...THEN RAIN/SNOW CHANCES FOCUSED ON WEDNESDAY NIGHT AND
THURSDAY. BEYOND THAT...COLDER TEMPERATURES FOR THE LATTER HALF OF
THE WEEK.
WATER VAPOR IMAGERY THIS MORNING SHOWS A LONGWAVE TROUGH OVER THE
EASTERN PACIFIC INTO THE WESTERN CONUS...WITH RIDGING ACROSS THE
GREAT LAKES. A WEAK SHORTWAVE TROUGH WAS OBSERVED ACROSS THE
NORTHERN PLAINS...WITH SUBSIDENCE ALOFT ACROSS NEBRASKA HELPING TO
KEEP THE MID-LEVELS DRY THIS MORNING. SEVERAL OTHER SHORTWAVES OF
NOTE WITHIN THE LONGWAVE TROUGH WERE ONE OVER NEVADA...WITH
ANOTHER STILL OVER THE OCEAN. AT THE SURFACE...SOUTH TO SOUTHEAST
FLOW WAS BRINGING IN LOW LEVEL MOISTURE AND WITH THE DRY AIR
ALOFT...FOG HAS DEVELOPED ACROSS ALMOST ALL OF NEBRASKA BY 08Z.
THIS HAS KEPT TEMPERATURES UP...WITH READINGS IN THE MID 40S TO
LOW 50S. THE OTHER FEATURE TO NOTE IS LOW PRESSURE ON THE LEE SIDE
OF THE ROCKIES.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ACCORDING TO THE RUC AND THE NAM...FOG SHOULD SLOWLY DISSIPATE
FROM THE WEST...BUT PLACES OVER THE EASTERN PART OF THE FORECAST
AREA...EAST OF HIGHWAY 83 COULD SEE THE FOG LINGER INTO THE EARLY
AFTERNOON HOURS. THE FOG WILL HAVE A BIG IMPACT ON HIGH
TEMPERATURES TODAY SO IF IT FAILS TO DISSIPATE BY 18Z OR
19Z...TEMPERATURES COULD BE UP TO 10 DEGREES TO WARM IN PLACES.
DAY SHIFT WILL NEED TO MONITOR TRENDS IN CASE TEMPERATURE FORECAST
NEEDS TO BE MODIFIED. 850MB TEMPERATURES WILL INCREASE TODAY
/BETWEEN 15C AND 23C/ DUE TO WARM AIR ADVECTION AHEAD OF THE AREA
OF LOW PRESSURE TO THE WEST. ASSUMING SKIES CLEAR...TEMPERATURES
SHOULD WARM CONSIDERABLY...WITH LOW 80S POSSIBLE ACROSS SOUTHWEST
NEBRASKA. THE SHORTWAVE TROUGH OVER NEVADA WILL LIFT INTO MONTANA
TODAY...WHICH WILL GIVE THE FRONT TO THE WEST A BIT OF A PUSH
EASTWARD. THE NAM PUSHES A DRYLINE ACROSS THE SANDHILLS THIS
AFTERNOON...WHICH COULD DROP DEWPOINTS INTO THE LOW 30S. GOING
SOUTH...DEWPOINTS WILL DROP INTO THE 30S AS WELL AS THE DRYLINE
PROGRESSES EAST. THIS WILL PROMOTE DEEP MIXING TO NEAR 700MB.
WINDS THROUGH THE MIXED LAYER WILL BE STRONGEST ACROSS NORTHWEST
NEBRASKA...WHERE GUSTS TO 30 MPH LOOK POSSIBLE THIS AFTERNOON.
GOING SOUTH...WINDS ALOFT DECREASE SO WINDY CONDITIONS ARE NOT
EXPECTED. WITH THE TEMPERATURES EXPECTED TODAY...LOWEST RELATIVE
HUMIDITY WILL BE ACROSS SOUTHWEST NEBRASKA...WITH VALUES DROPPING
TO THE MID 20S WHERE WINDS WILL BE STRONG. AS IS
FORECAST...CRITICAL FIRE WEATHER CONDITIONS WILL NOT BE
MET...ALTHOUGH MARGINAL CONDITIONS WILL BE LIKELY IN A FEW
LOCATIONS FOR AT LEAST A FEW HOURS TODAY. AGAIN...CLOUD COVER
COULD HAMPER THIS FROM OCCURRING...SO WILL NEED TO MONITOR TRENDS
FOR POTENTIAL FIRE WEATHER ISSUES TODAY.
THE MONTANA WAVE LIFTS INTO CANADA TONIGHT...WITH A COLD FRONT TO
THE WEST PROGRESSING SOUTHEAST ACROSS NEBRASKA TONIGHT. BY MID
MORNING WEDNESDAY SHOULD BE THROUGH MOST OF THE FORECAST AREA.
COULD AGAIN SEE SOME FOG WEDNESDAY MORNING...BUT THIS SHOULD BE
CONFINED TO AREAS RIGHT ALONG AND BEHIND THE FRONT WHERE LOW LEVEL
MOISTURE POOLS. A THE SHORTWAVE TROUGH WILL ALSO MOVE ONLAND
TONIGHT...WHICH WILL THEN PROGRESS ACROSS UTAH AND INTO COLORADO
ON WEDNESDAY. AS THIS IS ONGOING...A 700MB TROUGH WILL PASS ACROSS
THE NORTHERN AND CENTRAL PLAINS WEDNESDAY AND WEDNESDAY NIGHT.
MODELS ARE SHOWING GOOD FRONTOGENETICAL FORCING...WHILE THE
LOCATION OF THE UPPER LEVEL JET STREAK PUTS NORTHWEST NEBRASKA IN
AN AREA OF GOOD LARGE-SCALE LIFT. THE SIGNAL HAS BEEN QUITE
CONSISTENT IN TIMING AND LOCATION OF THE BEST FORCING FROM THE
DIFFERENT MODELS OVER THE PAST FEW DAYS SO CONFIDENCE HAS
INCREASED IN GETTING PRECIPITATION ACROSS THE FORECAST AREA. IT
MAY TAKE A BIT OF TIME TO SATURATE THE LOW LEVELS...SO ONLY BEGAN
CHANCES FOR RAIN IN THE FAR NORTHERN PARTS OF SHERIDAN AND CHERRY
COUNTIES WEDNESDAY MORNING AND SLOWLY EXPANDING SOUTH THROUGH THE
AFTERNOON. WEDNESDAY EVENING LOOKS TO SEE THE BEST CHANCES FOR
PRECIPITATION IN AREAS NORTHWEST OF AN IMPERIAL TO VALENTINE
LINE...AND THOUGH DO HAVE RAIN CHANCES TO THE EAST...LOWERED
CHANCES BEFORE MIDNIGHT AS TOO MUCH DRY AIR LOOKS TO EXIST IN
THESE AREAS. THE PRECIPITATION AREA DOES SHIFT TO THE SOUTH AND
EAST AFTER MIDNIGHT...BUT AS THE PRIMARY SHORTWAVE TROUGH EXITS
THE AREA BY 12Z THURSDAY MORNING...LARGE-SCALE FORCING WILL
DETERIORATE SO CHANCES HAVE LOWERED FOR THURSDAY. BY LATE
AFTERNOON THURSDAY...EXPECT THE FORECAST AREA TO SEE PRIMARILY DRY
CONDITIONS. THERE IS ANOTHER SHORTWAVE THAT WILL ROUND THE
LONGWAVE TROUGH LATER THURSDAY AND THURSDAY NIGHT...BUT THE TREND
CONTINUES TO GO SOUTH SO PRECIPITATION CHANCES LOOK TO STAY TO THE
SOUTH. TEMPERATURE PROFILES CONTINUE TO SHOW THE PRECIPITATION
TYPE BEGIN AS RAIN...BUT CHANGE OVER TO A RAIN/SNOW MIX WITH SNOW
BECOMING THE DOMINANT TYPE ACROSS THE NORTHWEST AREAS AFTER
MIDNIGHT WEDNESDAY NIGHT. HAVE RAIN OR SNOW IN THE FORECAST ACROSS
THE ENTIRE AREA FOR THURSDAY MORNING AS THE PROFILES HUG 0C IN THE
LOWEST LEVELS ABOVE THE SURFACE. DON/T EXPECT MUCH ACCUMULATION OF
SNOW...WITH PRECIPITATION ACCUMULATIONS UP TO A THIRD OF AN INCH
MAINLY NORTH OF INTERSTATE 80.
LONG TERM...FRIDAY THROUGH MONDAY
COLD TEMPERATURES WILL BE THE HIGHLIGHT FOR THE WEEKEND AS HIGHS
WILL BE HARD PRESSED TO MAKE IT OUT OF THE 30S AND 40S FOR FRIDAY
AND SATURDAY. LOWS ALSO WILL BE QUITE COLD...ALTHOUGH THE 23.00Z
MODEL SOLUTIONS ARE A BIT WARMER FOR BOTH FRIDAY AND SATURDAY
NIGHTS WITH THE SURFACE HIGH NOW LOOKING TO STAY OFF TO THE EAST
OF THE FORECAST AREA. LOWS SHOULD STILL EASILY DROP INTO THE
20S...WITH TEENS POSSIBLE FRIDAY NIGHT.
THE TREND NOW LOOKS FOR WARMER CONDITIONS GOING INTO NEXT WEEK AS
RIDGING BUILDS OVER THE WESTERN HALF OF THE COUNTRY. THIS WILL
BRING MILD TEMPERATURES BACK INTO THE CENTRAL PLAINS WITH 850MB
TEMPERATURES WARMING INTO THE TEENS AGAIN BY MONDAY...COMPARED TO
READINGS BELOW 0C WHICH WILL BE EXPERIENCED FRIDAY AND SATURDAY.
THE FORECAST IS DRY THROUGH THIS PERIOD AS THE LONGWAVE TROUGH
WILL PUSH THE MOISTURE ACROSS THE PLAINS WELL TO THE
SOUTHEAST.
AVIATION...
LIFR/IFR CIGS AND VSBY IMPROVE TO VFR FROM WEST TO EAST BETWEEN 15Z
AND 18Z ALONG AND WEST OF HIGHWAY 83. EAST OF HIGHWAY 83...LIFR/IFR
CIGS AND VIS IMPROVE TO IFR/MVFR CIGS AROUND 18Z AND THEN VFR BY 21Z.
A COLD FRONT WILL DROP INTO THE FCST AREA TONIGHT WITH MVFR/IFR CIGS
POSSIBLE AFTER 06Z TUESDAY NIGHT.
FIRE WEATHER...
POTENTIAL RED FLAG CONDITIONS WILL BE MONITORED ACROSS WRN NEB THIS
AFTERNOON DEPENDING ON THE PROGRESS OF A CLEARING LINE FCST TO
DEVELOP ACROSS THE PANHANDLE THIS MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT TUE OCT 23 2012
.AVIATION...18 KGRI TAF. PREVAILING LIFR CONDITIONS FORECAST
THROUGH 20Z...WITH VFR CONDITIONS EVENTUALLY RESTORED BY
22Z...FOLLOWED BY ANOTHER ROUND OF LIFR CONDITIONS WEDNESDAY
MORNING. STRATUS PERSISTS ACROSS MUCH OF THE REGION AT THIS
HOUR...HOWEVER SATELLITE IMAGERY INDICATES CLEARING TO THE
SOUTHEAST AND THE NORTHWEST OF THE TERMINAL. UNFORTUNATELY KGRI
WILL BE ONE OF THE LAST LOCATIONS TO EXPERIENCE CLEARING
TODAY...BUT EVEN THEN CLOUDS ARE EXPECTED TO SCATTER OUT BY 22Z.
VFR CONDITIONS SHOULD PERSIST THROUGH MUCH OF TONIGHT...WITH THE
REDEVELOPMENT OF STRATUS PROMOTING LIFR CONDITIONS AT THE TERMINAL
BY 11Z WEDNESDAY. VISIBILITY RESTRICTIONS IN FOG AND/OR DRIZZLE
WILL REMAIN POSSIBLE AT THE TERMINAL THROUGH 20Z TODAY...AND AGAIN
11Z AND BEYOND ON WEDNESDAY. THE SURFACE WIND WILL REMAIN
GENERALLY LIGHT AND VARIABLE THROUGH THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1111 AM CDT TUE OCT 23 2012/
UPDATE...MORNING UPPER AIR ANALYSIS INDICATES LONG WAVE TROUGHING
OVER THE WESTERN HALF OF THE CONUS AND RIDGING OVER THE EAST. MID
AND UPPER LEVEL JET ENERGY EXTENDS FROM CALIFORNIA...NORTHEAST
ACROSS THE ROCKY MOUNTAIN RANGE INTO THE NORTHERN PLAINS...THEN
INTO SOUTH CENTRAL CANADA AND THEN EAST/SOUTHEAST INTO
SOUTHEASTERN CANADA AND THE NORTHEASTERN CONUS. TROPOSPHERIC FLOW
OVER THE CENTRAL PLAINS IS NOT PARTICULARLY STRONG AS A
RESULT...WITH THE WIND PEAKING OUT AT AROUND 70KTS NEAR 200MB.
WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL
MOISTURE EXTENDING ALONG THE JET AXIS FROM THE WESTERN CONUS INTO
SOUTH CENTRAL CANADA...HOWEVER MUCH OF THIS MID LEVEL MOISTURE
REMAINS NORTHWEST OF OUR AREA. AT THE SURFACE A STATIONARY FRONT
IS NOTED EXTENDING FROM SOUTHWESTERN IOWA...SOUTHWEST TO NEAR
KCNK...KGBD AND KDDC. THE LOW LEVEL WIND FIELD ACROSS OUR CWA
REMAINS FAIRLY LIGHT THIS MORNING...HOWEVER THE PREDOMINANT WIND
DIRECTION REMAINS FROM THE EAST/NORTHEAST DUE TO THE LOW LEVEL
BAROCLINIC ZONE TO OUR SOUTHEAST. ISENTROPIC UPGLIDE AND
SATURATION ACROSS THE LOW LEVEL BAROCLINIC ZONE...PRIMARILY ALONG
THE 290-295K SURFACES...CONTINUES TO PROMOTE WIDESPREAD STRATUS
ACROSS THE REGION THIS MORNING...WITH CEILINGS HOLDING GENERALLY
IN THE 100-300FT AGL RANGE ACROSS OUR AREA. IN ADDITION TO THIS
STRATUS...LOW LEVEL MOISTURE FLUX INTO THE AREA IS ALSO WORKING TO
PROMOTE CONTINUED FOG ACROSS MUCH OF THE AREA...WITH ENOUGH LOW
LEVEL TURBULENT MIXING FOR DRIZZLE AS WELL...PRIMARILY ACROSS OUR
EASTERN CWA. AS OF 1530Z THE LOWEST VISIBILITIES EXIST ALONG A
LINE FROM KAUH...TO KGRI...TO KEAR...TO KHDE AND KPHG...WHICH IS
WHERE VISIBILITY RESTRICTIONS OF 1/4SM TO 1/2SM ARE IN EXISTENCE.
TO THE NORTHWEST AND SOUTHEAST OF THIS LINE...VISIBILITY
RESTRICTIONS OF AROUND 1SM ARE BEING OBSERVED.
IMPROVEMENTS IN VISIBILITY HAVE BEEN NOTED ACROSS MUCH OF THE CWA
THROUGH PAST FEW HOURS WITH MOST LOCATIONS ACROSS OUR CWA NOW
ABOVE 1/4SM. AS A RESULT...THE DENSE FOG ADVISORY WAS LET GO AT
15Z. THAT BEING SAID...FOG...WITH VISIBILITY RESTRICTIONS
GENERALLY BETWEEN 1/2SM AND 1SM...STILL PERSISTS ACROSS THE AREA
AND WILL LIKELY BE OBSERVED THROUGH AT LEAST MIDDAY. BIGGEST
QUESTION FOR THE REST OF TODAY IS WHETHER OR NOT ENOUGH DIABATIC
HEATING WILL BE REALIZED FOR COMPLETE FOG DISSIPATION. THE CURRENT
HOPE IS THAT THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY TO OUR
SOUTHEAST...WILL MAKE ENOUGH PROGRESS NORTH/NORTHWEST ACROSS OUR
AREA...THUS PUSHING THE BEST ISENTROPIC UPGLIDE TO OUR NORTH AND
CARRYING THE CLOUD COVER WITH IT. WITH CLOUD COVER DIMINISHING
OVER MUCH OF OUR AREA AND INCREASING DIABATIC HEATING...ENOUGH OF
A LOW LEVEL DEWPOINT DEPRESSION SHOULD PRESENT ITSELF FOR COMPLETE
FOG DISSIPATION AND SUNNIER SKIES THIS AFTERNOON. IF HOWEVER THE
LOW LEVEL BAROCLINIC ZONE DOES NOT MAKE AS MUCH PROGRESS
NORTH/NORTHWEST AS CURRENTLY EXPECTED...THEN THIS AFTERNOON COULD
TURN OUT BEING MUCH CLOUDIER THAN FORECAST...WITH FOG POTENTIALLY
PERSISTING THROUGH MUCH OF THE DAY. WITH CURRENT SHORT TERM
GUIDANCE SUGGESTING SUNNIER SKIES ACROSS MOST ALL OF THE CWA THIS
AFTERNOON...WILL STAY THE COURSE AND CONTINUE PRESENT PARTLY
CLOUDY SKIES WITH HIGHS IN THE 60S AND 70S FOR THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 516 AM CDT TUE OCT 23 2012/
SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER NIGHT...AND ANOTHER
SET OF SEVERAL TRICKY FORECAST ELEMENTS DURING THE NEXT 72
HOURS...NAMELY HIGH TEMPS AND PRECIP/FOG TRENDS...AND WHETHER ANY
STORMS WED NIGHT MIGHT GO SEVERE.
09Z OBJECTIVE SURFACE ANALYSIS CONFIRMS THAT THE ENTIRE CWA LIES
NORTH OF A QUASI-STATIONARY BOUNDARY SNAKING EAST-NORTHEAST ACROSS
SOUTHERN/EASTERN KANSAS AND EXTENDING FROM A WEAK 1003MB LOW IN
SOUTHEAST CO. BREEZES ACROSS THE CWA RANGE FROM LIGHT/VARIABLE TO
LIGHT EASTERLY...WITH LITTLE IF ANY TEMP/DEWPOINT DEPRESSION WITH
VALUES RANGING GENERALLY 47-53 ALL AREAS. AS EXPECTED 24 HOURS
AGO...VARYING DEGREES OF FOG HAVE SETTLED IN OVERNIGHT...WITH THE
ENTIRE CWA SEEING NO BETTER THAN 2-3 MILE VISIBILITY...AND THE MOST
CONCENTRATED ZONE OF DENSE FOG 1/4 MILE OR LOWER VSBY FOCUSED FROM
I-80 SOUTHWARD INTO KANSAS PER AUTOMATED OBS AND WEBCAMS. LIGHT
DRIZZLE HAS SEEMINGLY BEEN OFF AND ON OVERNIGHT...BUT IS LIKELY
STILL PRESENT IN MUCH OF THE CWA. ALOFT...WATER VAPOR SATELLITE
IMAGERY AND LATEST MODEL DATA CONFIRM BROAD WEST- SOUTHWEST FLOW
OVER THE CENTRAL PLAINS...WHICH IS POSITIONED DOWNSTREAM FROM A
LARGE SCALE TROUGH ANCHORED ACROSS THE PACIFIC NORTHWEST WITH A
CLOSED 500MB LOW OFF THE WASHINGTON STATE COAST. CLOSER TO
HOME...A SMALL SCALE SHORTWAVE TROUGH IS CURRENTLY DEPARTING
EASTWARD ACROSS MO...PROMOTING CONSIDERABLE ELEVATED THUNDERSTORM
ACTIVITY IN THAT AREA.
STARTING OFF EARLY THIS MORNING...THE MOST IMMEDIATE ISSUE IS THE
ONGOING CWA-WIDE DENSE FOG ADVISORY VALID THROUGH 15Z...AND WILL
LET IT RIDE AS-IS FOR NOW. TECHNICALLY SPEAKING...AUTOMATED OBS
SUGGEST THAT SO FAR THE MAJORITY OF ANY LOCALLY DENSE FOG HAS BEEN
CONFINED TO AREAS SOUTH OF THE I-80 CORRIDOR...BUT VARIOUS SHORT
TERM VISIBILITY GUIDANCE FROM THE HRRR/SREF SUGGEST THAT A
NORTHWARD EXPANSION OF DENSE FOG IS QUITE POSSIBLE YET THIS
MORNING...AND AM NOT ABOUT TO CANCEL ANY OF THIS ADVISORY UNTIL
TRENDS CAN BE MONITORED FOR AT LEAST A FEW MORE HOURS. IN
FACT...AM STARTING TO EVEN WONDER IF THE 15Z EXPIRATION TIME WILL
BE LONG ENOUGH...WITH BOTH THE HRRR AND HOURLY GFS LAMP GUIDANCE
SUGGESTING THAT SOME AREAS COULD REMAIN RATHER SOCKED IN UNTIL AT
LEAST 16Z-17Z. DAY SHIFT WILL HAVE TO KEEP AN EYE ON THE POSSIBLE
NEED FOR AN EXTENSION. AS FOR THE OFF AND ON LIGHT DRIZZLE SUCH AS
OBSERVED HERE AT THE WFO TONIGHT...HAVE IT MENTIONED CWA-WIDE
THROUGH 12Z...BUT HAVE THEN ATTEMPTED TO CONFINE IT TO ONLY A
HANDFUL OF COUNTIES EAST OF HWY 281 POST-SUNRISE...WHERE NAM
SOUNDINGS INDICATED THAT THE SATURATED LAYER WOULD REMAIN
DEEPER...GENERALLY NEAR/IN EXCESS OF 2500 FT. THAT BEING
SAID...CANNOT COMPLETELY RULE OUT POST-SUNRISE LIGHT DRIZZLE EVEN
IN THE TRI-CITIES AREA WESTWARD GIVEN SUCH A MOIST LOW LEVEL
PROFILE. AS FOR SKY COVER...CONFIDENCE IS CONSIDERABLY HIGHER
TODAY THAT MUCH OF THE CWA WILL SEE AT LEAST A FEW HOURS OF PARTLY
TO MOSTLY SUNNY SKIES AT SOME POINT...BUT EXACTLY WHEN IS STILL
IN QUESTION. HAVE GENERALLY FOLLOWED THE 00Z/06Z NAM SOLUTION OF
KEEPING NEARLY ALL AREAS SOCKED IN WITH STRATUS AND AT LEAST LIGHT
FOG THROUGH THE MORNING HOURS...BUT THEN ERODING FROM WEST-EAST
THROUGH THE AFTERNOON WEARS ON AS EVIDENCED BY THE 900MB RELATIVE
HUMIDITY FIELD. THIS MEANS THAT FAR EASTERN COUNTIES ALONG THE HWY
81 WOULD BE LAST TO SEE ANY CLEARING. AFTER BUSTING HIGH TEMPS BY
10+ DEGREES YESTERDAY DUE TO WIDESPREAD LOW STRATUS...AM IN NO
HURRY TO GO WITH THE WARM END OF AVAILABLE GUIDANCE/MODEL
SOLUTIONS TODAY ESPECIALLY IN EASTERN ZONES. AFTER TRYING VARIOUS
SOLUTIONS ON FOR SIZE...ENDED UP GOING WITH THE 00Z NAM ALMOST
EXACTLY...AS ITS TEMP FIELD SEEMED TO BEST-CAPTURE THE GRADUAL
WEST-EAST CLEARING. THIS RESULTS IN A DECENT RANGE FROM NEAR 80
FAR WEST ...LOW-MID 70S CENTRAL AND UPPER 60S EAST. PLEASE NOTE
THESE VALUES ARE AT LEAST A FEW DEGREES COOLER THAN PREVIOUS
FORECAST ALL AREAS...AND AS MUCH AS 5-8 DEGREES COOLER IN THE
EAST. LIKE YESTERDAY...COULD EASILY FORESEE HIGHS BEING OFF BY 5+
DEGREES DEPENDING ON STRATUS/FOG TRENDS.
TONIGHT...KEPT OUT ALL MENTION OF PRECIP CWA-WIDE...AND AM NOT
EXPECTING A DENSE FOG REPEAT SUCH AS THE ONGOING ONE...BUT DID
INSERT A PATCHY FOG MENTION INTO SEVERAL COUNTIES NORTH OF I-80
AFTER MIDNIGHT IN CLOSEST PROXIMITY TO THE HIGHEST BOUNDARY LAYER
RELATIVE HUMIDITY POOLING IN THE VICINITY OF THE LEADING EDGES OF
THE INVADING COLD FRONT. CLOUD TRENDS TONIGHT ARE CERTAINLY A
CHALLENGE...WITH THE POTENTIAL FOR QUITE AN INCREASE IN STRATUS
TOWARD SUNRISE NEAR THIS BOUNDARY...FOLLOWING WHAT SHOULD BE A
FAIRLY CLEAR EVENING FOR MOST AREAS. ALOFT...THE BIG PICTURE
INVOLVES A LEAD SHORTWAVE TRACKING ACROSS FAR SOUTH CENTRAL
CANADA...WHICH HELPS DRIVE THE SURFACE FRONT INTO THE NORTHERN
CWA...WHILE A TROUGH AXIS SETS UP FROM SOUTHWEST-NORTHEAST ACROSS
KS. KEPT LOWS SIMILAR TO PREVIOUS FORECAST AND A GUIDANCE
BLEND...RANGING FROM LOW-MID 40S NORTHWEST TO UPPER 50S/NEAR 60
SOUTHEAST WHERE DEWPOINTS WILL BE ON THE INCREASE.
WEDNESDAY...OTHER THAN THE LINGERING PATCHY FOG MENTION NORTH IN
THE MORNING...HAVE KEPT OUT ANY OTHER WEATHER MENTION THROUGH
SUNSET...AS THE GENERAL MODEL CONSENSUS IS TO KEEP ANY LIGHT
DAYTIME DRIZZLY PRECIP NORTHEAST OF THE CWA...AND ANY LATE-DAY
CONVECTION ALONG/NEAR THE INVADING COLD FRONT JUST SOUTHEAST OF
THE CWA. THAT BEING SAID...SKY COVER AND TEMP TRENDS ARE AGAIN
QUITE A CHALLENGE...AS QUITE A BIT OF STRATUS SHOULD DOMINATE MUCH
OF THE NORTHWEST CWA WITH MORE SUNSHINE SOUTHEAST.
FORTUNATELY...THE LATEST MODEL RUNS ARE IN REASONABLY GOOD
AGREEMENT REGARDING WHAT WILL CERTAINLY BE A SHARP TEMP
GRADIENT...AND ONLY MADE MINOR ADJUSTMENTS TO PREVIOUS
FORECAST...AIMING FOR A RANGE FROM UPPER 50S FAR NORTH...MID 60S
TO LOW 70S TRI CITIES AREA...AND LOW 80S FAR SOUTHEAST IN THE
HEBRON-BELOIT CORRIDOR. AGAIN THOUGH...5+ DEGREE DEVIATIONS FROM
CURRENT FORECAST ARE VERY POSSIBLE IF NOT LIKELY. PONDERED GOING
WITH A NON-DIURNAL TEMP TREND BEHIND THE FRONT...BUT MODELS ARE
NOT REALLY SHOWING MUCH OF AN AFTERNOON DROP SO STUCK WITH
TRADITIONAL MID-LATE AFTERNOON HIGHS ALL AREAS FOR NOW. THIS COLD
FRONT WILL NOT EXACTLY BLAST THROUGH THE AREA...AND BY SUNSET WILL
JUST BE REACHING FAR SOUTHEAST ZONES...WHILE MOST OF THE CWA WILL
ALREADY BE IN SUSTAINED NORTH WINDS 15-20 MPH.
WEDNESDAY NIGHT IS CLEARLY STILL THE MAIN 12-HOUR WINDOW FOR
POTENTIALLY DECENT RAIN AMOUNTS...AND ACTUALLY RAISED POPS INTO
THE 60-70 PERCENT RANGE ACROSS MUCH OF THE EASTERN CWA...WHILE
LEAVING SOUTHWEST AREAS IN THE 40-50 PERCENT RANGE. IN
SHORT...LARGE SCALE FORCING/MID LEVEL FRONTOGENESIS RAMPS UP AS A
POTENT OPEN WAVE OVER THE CENTRAL ROCKIES MOVES INTO THE CENTRAL
PLAINS...FEATURING A 110+KT 300MB JET STREAK. LEFT THE POP/WEATHER
GRIDS AS ONE 12-HOUR BLOCK FOR NOW...BUT GENERAL THINKING IS THAT
MOST WIDESPREAD COVERAGE OF SHOWERS/STORMS WILL HOLD OFF UNTIL
NEAR/AFTER MIDNIGHT...UNLESS SOME EVENING ACTIVITY FLARES UP IN
THE FAR SOUTH/SOUTHEAST NEAR THE MAIN SURFACE FRONT. LATEST NAM
CONTINUES TO SHOW A HEALTHY CORRIDOR OF MUCAPE 1500+ J/KG IN THE
850-700MB LAYER MAINLY ACROSS THE SOUTHEAST 1/2 OF THE
CWA...DROPPING OFF SHORTLY TO THE NORTHWEST. HOWEVER...WILL KEEP
ISOLATED THUNDER EVEN IN THIS NORTHWEST AREAS. WITH VERY STRONG
DEEP-LAYER SHEAR OF 60+ KNOTS MOVING IN...HAVE INCREASING CONCERNS
THAT AT LEAST MARGINALLY SEVERE HAIL COULD OCCUR IN SOUTHEAST
COUNTIES...AND DESPITE SPC KEEPING THE OFFICIAL DAY2 SLIGHT RISK
OUTLOOK JUST EAST OF THE CWA...AT LEAST FOR NOW...WILL GO AHEAD
AND ADD THIS MENTION TO THE HAZARDOUS WEATHER OUTLOOK AS THESE
STRONG DYNAMICS ARE HARD TO IGNORE. DEPENDING ON HOW WIDESPREAD
STORMS ARE...COULD FORESEE SOME FORTUNATE AREAS RECEIVING IN
EXCESS OF ONE-HALF INCH OF RAIN BUT THIS WILL PROBABLY BE THE
EXCEPTION. ALTHOUGH SOME SNOW OR RAIN/SNOW MIX COULD TRY
DEVELOPING IN WESTERN NEBRASKA IN THE COLDER AIR WELL BEHIND THE
FRONT...LATEST CONSENSUS IS THAT WINTRY PRECIP WED NIGHT SHOULD
FOCUS AT LEAST 50 MILES WEST OF THE CWA...AND THUS WILL KEEP ANY
SNOW MENTION OUT FOR NOW.
THURSDAY...SPLIT THE DAY INTO 6-HOUR BLOCKS...WITH ALL PRECIP GONE
BY THE AFTERNOON HOURS...AND POTENTIALLY EVEN GONE BY MID-MORNING
IN MOST AREAS PER SOME OF THE LATEST TRENDS INCLUDING THE 00Z
ECMWF...WHICH QUICKLY SHUTS OFF THE MID LEVEL LIFT/SATURATION FROM
NORTHWEST-SOUTHEAST. LATER ADJUSTMENTS WILL BE NEEDED...BUT FOR NOW
KEPT 20-40 POPS ACROSS MOST OF THE CWA IN THE MORNING FOR GENERAL
LIGHT RAIN...WITH NO THUNDER MENTION AND STILL NO SNOW
MENTION...ALTHOUGH SUPPOSE A FEW FLURRIES COULD SNEAK INTO FAR
NORTHWEST ZONES JUST BEFORE PRECIP SHUTS OFF FOR GOOD GIVEN
SURFACE TEMPS FORECAST TO DROP INTO THE MID 30S EARLY THURSDAY
MORNING. OTHERWISE...EXPECT INCREASING SUNSHINE AS THE DAY WEARS
ON...ALTHOUGH IT WILL REMAIN QUITE BREEZY WITH SUSTAINED NORTH
WINDS AROUND 20 MPH WITH GUSTS TO AROUND 30 MPH. FOR HIGH
TEMPS...RAW NAM VALUES ARE WELL INTO THE MID 50S ALL AREAS...BUT
WAS NOT WILLING TO GO QUITE THIS WARM YET...AND THUS ONLY MADE
MINOR ADJUSTMENTS TO PREVIOUS FORECAST WITH MOST NEB ZONES TOPPING
OUT UPPER 40S AND KS LOWER 50S.
THURS NIGHT...THIS LOOKS TO BE THE MOST UNEVENTFUL PERIOD OF THE
NEXT 72 HOURS...AS AN EXPANSIVE SURFACE RIDGE AXIS SETTLES INTO
THE REGION FROM THE NORTH...AND ANY LIGHT SNOW ACCUMULATIONS
ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE ENERGY AND LOW LEVEL
UPSLOPE FLOW SHOULD REMAIN NO CLOSER THAN THE NEB/CO/KS BORDER
AREA. DESPITE A POTENTIAL INCREASE IN MID LEVEL CLOUDS...OPTED TO
LOWER LOW TEMPS 2-3 DEGREES FROM PREVIOUS FCST AND POSSIBLY NOT
ENOUGH...BUT AT LEAST GETTING ALL AREAS INTO THE SUB-FREEZING
26-32 RANGE.
LONG TERM...STARTING 12Z FRIDAY...THE LONGWAVE TROUGH ACROSS THE
WEST COAST THIS MORNING WILL BE CENTERED OVER THE PLAINS ON
FRIDAY...WITH SEVERAL EMBEDDED WEAK DISTURBANCES EXPECTED TO HAVE
LITTLE IMPACT IN THE WAY OF CHANCES FOR PRECIP ACROSS THE LOCAL
AREA. SOME DISCREPANCIES EVIDENT WITH THE HANDLING OF THIS TROUGH
AS IT PUSHES EAST LATE IN THE WEEKEND...WITH THE EC QUICKLY BUILDING
A RIDGE OVER THE INTERMOUNTAIN WEST RESULTING IN RISING HEIGHTS
ACROSS THE PLAINS...IN RESPONSE TO THE LONGWAVE TROUGH INTERACTS
WITH A TROPICAL DISTURBANCE OFF THE EASTERN SEABOARD...AND THE
LATEST GFS DEPICTING A MORE ZONAL WEST TO NORTHWEST FLOW ACROSS THE
REGION BY EARLY NEXT WEEK...AS THE AFOREMENTIONED TROPICAL
DISTURBANCE INSTEAD TRACKS OUT INTO THE OPEN ATLANTIC. EITHER
WAY...THIS APPEARS TO BE A DRY PATTERN FOR THE LOCAL AREA AS THERE
ARE NO SIGNIFICANT FEATURES FORECAST TO IMPACT THE AREA IN THE
DIVERGENT UPPER LEVEL FLOW PATTERNS DEPICTED AMONGST THE LONG TERM
MODELS. THEREFORE...EXPECT DRY CONDITIONS...WITH CONTINUED
UNSEASONABLY COOL TEMPERATURES...TO AT LEAST START THE EXTENDED
PERIODS...WITH TEMPERATURES POSSIBLY WARMING CLOSER TO
CLIMATOLOGY...WHILE REMAINING DRY...EARLY NEXT WEEK IF THE EC
SOLUTION ENDS UP BEING CORRECT. HOWEVER...DUE TO THE UNCERTAINTY OF
THE SYNOPTIC SCALE PATTERN EARLY NEXT WEEK...STUCK WITH ALLBLEND
MODEL SOLUTION THIS MORNING...WITH NO NOTABLE TWEAKS TO SPEAK OF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/UPDATE...BRYANT
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1111 AM CDT TUE OCT 23 2012
.UPDATE...MORNING UPPER AIR ANALYSIS INDICATES LONG WAVE TROUGHING
OVER THE WESTERN HALF OF THE CONUS AND RIDGING OVER THE EAST. MID
AND UPPER LEVEL JET ENERGY EXTENDS FROM CALIFORNIA...NORTHEAST
ACROSS THE ROCKY MOUNTAIN RANGE INTO THE NORTHERN PLAINS...THEN
INTO SOUTH CENTRAL CANADA AND THEN EAST/SOUTHEAST INTO
SOUTHEASTERN CANADA AND THE NORTHEASTERN CONUS. TROPOSPHERIC FLOW
OVER THE CENTRAL PLAINS IS NOT PARTICULARLY STRONG AS A
RESULT...WITH THE WIND PEAKING OUT AT AROUND 70KTS NEAR 200MB.
WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL
MOISTURE EXTENDING ALONG THE JET AXIS FROM THE WESTERN CONUS INTO
SOUTH CENTRAL CANADA...HOWEVER MUCH OF THIS MID LEVEL MOISTURE
REMAINS NORTHWEST OF OUR AREA. AT THE SURFACE A STATIONARY FRONT
IS NOTED EXTENDING FROM SOUTHWESTERN IOWA...SOUTHWEST TO NEAR
KCNK...KGBD AND KDDC. THE LOW LEVEL WIND FIELD ACROSS OUR CWA
REMAINS FAIRLY LIGHT THIS MORNING...HOWEVER THE PREDOMINANT WIND
DIRECTION REMAINS FROM THE EAST/NORTHEAST DUE TO THE LOW LEVEL
BAROCLINIC ZONE TO OUR SOUTHEAST. ISENTROPIC UPGLIDE AND
SATURATION ACROSS THE LOW LEVEL BAROCLINIC ZONE...PRIMARILY ALONG
THE 290-295K SURFACES...CONTINUES TO PROMOTE WIDESPREAD STRATUS
ACROSS THE REGION THIS MORNING...WITH CEILINGS HOLDING GENERALLY
IN THE 100-300FT AGL RANGE ACROSS OUR AREA. IN ADDITION TO THIS
STRATUS...LOW LEVEL MOISTURE FLUX INTO THE AREA IS ALSO WORKING TO
PROMOTE CONTINUED FOG ACROSS MUCH OF THE AREA...WITH ENOUGH LOW
LEVEL TURBULENT MIXING FOR DRIZZLE AS WELL...PRIMARILY ACROSS OUR
EASTERN CWA. AS OF 1530Z THE LOWEST VISIBILITIES EXIST ALONG A
LINE FROM KAUH...TO KGRI...TO KEAR...TO KHDE AND KPHG...WHICH IS
WHERE VISIBILITY RESTRICTIONS OF 1/4SM TO 1/2SM ARE IN EXISTENCE.
TO THE NORTHWEST AND SOUTHEAST OF THIS LINE...VISIBILITY
RESTRICTIONS OF AROUND 1SM ARE BEING OBSERVED.
IMPROVEMENTS IN VISIBILITY HAVE BEEN NOTED ACROSS MUCH OF THE CWA
THROUGH PAST FEW HOURS WITH MOST LOCATIONS ACROSS OUR CWA NOW
ABOVE 1/4SM. AS A RESULT...THE DENSE FOG ADVISORY WAS LET GO AT
15Z. THAT BEING SAID...FOG...WITH VISIBILITY RESTRICTIONS
GENERALLY BETWEEN 1/2SM AND 1SM...STILL PERSISTS ACROSS THE AREA
AND WILL LIKELY BE OBSERVED THROUGH AT LEAST MIDDAY. BIGGEST
QUESTION FOR THE REST OF TODAY IS WHETHER OR NOT ENOUGH DIABATIC
HEATING WILL BE REALIZED FOR COMPLETE FOG DISSIPATION. THE CURRENT
HOPE IS THAT THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY TO OUR
SOUTHEAST...WILL MAKE ENOUGH PROGRESS NORTH/NORTHWEST ACROSS OUR
AREA...THUS PUSHING THE BEST ISENTROPIC UPGLIDE TO OUR NORTH AND
CARRYING THE CLOUD COVER WITH IT. WITH CLOUD COVER DIMINISHING
OVER MUCH OF OUR AREA AND INCREASING DIABATIC HEATING...ENOUGH OF
A LOW LEVEL DEWPOINT DEPRESSION SHOULD PRESENT ITSELF FOR COMPLETE
FOG DISSIPATION AND SUNNIER SKIES THIS AFTERNOON. IF HOWEVER THE
LOW LEVEL BAROCLINIC ZONE DOES NOT MAKE AS MUCH PROGRESS
NORTH/NORTHWEST AS CURRENTLY EXPECTED...THEN THIS AFTERNOON COULD
TURN OUT BEING MUCH CLOUDIER THAN FORECAST...WITH FOG POTENTIALLY
PERSISTING THROUGH MUCH OF THE DAY. WITH CURRENT SHORT TERM
GUIDANCE SUGGESTING SUNNIER SKIES ACROSS MOST ALL OF THE CWA THIS
AFTERNOON...WILL STAY THE COURSE AND CONTINUE PRESENT PARTLY
CLOUDY SKIES WITH HIGHS IN THE 60S AND 70S FOR THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 556 AM CDT TUE OCT 23 2012/
AVIATION...12Z KGRI TAF...STRATUS CONTINUES TO COVER A GOOD
PORTION OF THE CENTRAL PLAINS THIS MORNING WITH LIFR/IFR CIGS
MIXED THROUGHOUT AREAS OF FG/BR/-DZ. EXPECT THE LIFR/IFR
CONDITIONS WILL PERSIST THROUGH AROUND 23/16Z...WHEN CIGS AND
VISIBILITIES ARE EXPECTED TO BEGIN TO IMPROVE MORE SUBSTANTIALLY
AS WINDS BEGIN TO INCREASE OUT OF THE SOUTH AND SOME MIXING ALLOWS
FOR CIGS/VSBYS TO BEGIN TO LIFT/IMPROVE. THIS IMPROVING TREND IS
EXPECTED TO CONTINUE THROUGH EARLY AFTERNOON...WITH A RETURN TO
VFR CIGS/VSBYS EXPECTED BY 23/19Z...AS INDICATED BY LATEST SHORT
TERM GUIDANCE.
PREV DISCUSSION... /ISSUED 516 AM CDT TUE OCT 23 2012/
SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER NIGHT...AND ANOTHER
SET OF SEVERAL TRICKY FORECAST ELEMENTS DURING THE NEXT 72
HOURS...NAMELY HIGH TEMPS AND PRECIP/FOG TRENDS...AND WHETHER ANY
STORMS WED NIGHT MIGHT GO SEVERE.
09Z OBJECTIVE SURFACE ANALYSIS CONFIRMS THAT THE ENTIRE CWA LIES
NORTH OF A QUASI-STATIONARY BOUNDARY SNAKING EAST-NORTHEAST ACROSS
SOUTHERN/EASTERN KANSAS AND EXTENDING FROM A WEAK 1003MB LOW IN
SOUTHEAST CO. BREEZES ACROSS THE CWA RANGE FROM LIGHT/VARIABLE TO
LIGHT EASTERLY...WITH LITTLE IF ANY TEMP/DEWPOINT DEPRESSION WITH
VALUES RANGING GENERALLY 47-53 ALL AREAS. AS EXPECTED 24 HOURS
AGO...VARYING DEGREES OF FOG HAVE SETTLED IN OVERNIGHT...WITH THE
ENTIRE CWA SEEING NO BETTER THAN 2-3 MILE VISIBILITY...AND THE MOST
CONCENTRATED ZONE OF DENSE FOG 1/4 MILE OR LOWER VSBY FOCUSED FROM
I-80 SOUTHWARD INTO KANSAS PER AUTOMATED OBS AND WEBCAMS. LIGHT
DRIZZLE HAS SEEMINGLY BEEN OFF AND ON OVERNIGHT...BUT IS LIKELY
STILL PRESENT IN MUCH OF THE CWA. ALOFT...WATER VAPOR SATELLITE
IMAGERY AND LATEST MODEL DATA CONFIRM BROAD WEST- SOUTHWEST FLOW
OVER THE CENTRAL PLAINS...WHICH IS POSITIONED DOWNSTREAM FROM A
LARGE SCALE TROUGH ANCHORED ACROSS THE PACIFIC NORTHWEST WITH A
CLOSED 500MB LOW OFF THE WASHINGTON STATE COAST. CLOSER TO
HOME...A SMALL SCALE SHORTWAVE TROUGH IS CURRENTLY DEPARTING
EASTWARD ACROSS MO...PROMOTING CONSIDERABLE ELEVATED THUNDERSTORM
ACTIVITY IN THAT AREA.
STARTING OFF EARLY THIS MORNING...THE MOST IMMEDIATE ISSUE IS THE
ONGOING CWA-WIDE DENSE FOG ADVISORY VALID THROUGH 15Z...AND WILL
LET IT RIDE AS-IS FOR NOW. TECHNICALLY SPEAKING...AUTOMATED OBS
SUGGEST THAT SO FAR THE MAJORITY OF ANY LOCALLY DENSE FOG HAS BEEN
CONFINED TO AREAS SOUTH OF THE I-80 CORRIDOR...BUT VARIOUS SHORT
TERM VISIBILITY GUIDANCE FROM THE HRRR/SREF SUGGEST THAT A
NORTHWARD EXPANSION OF DENSE FOG IS QUITE POSSIBLE YET THIS
MORNING...AND AM NOT ABOUT TO CANCEL ANY OF THIS ADVISORY UNTIL
TRENDS CAN BE MONITORED FOR AT LEAST A FEW MORE HOURS. IN
FACT...AM STARTING TO EVEN WONDER IF THE 15Z EXPIRATION TIME WILL
BE LONG ENOUGH...WITH BOTH THE HRRR AND HOURLY GFS LAMP GUIDANCE
SUGGESTING THAT SOME AREAS COULD REMAIN RATHER SOCKED IN UNTIL AT
LEAST 16Z-17Z. DAY SHIFT WILL HAVE TO KEEP AN EYE ON THE POSSIBLE
NEED FOR AN EXTENSION. AS FOR THE OFF AND ON LIGHT DRIZZLE SUCH AS
OBSERVED HERE AT THE WFO TONIGHT...HAVE IT MENTIONED CWA-WIDE
THROUGH 12Z...BUT HAVE THEN ATTEMPTED TO CONFINE IT TO ONLY A
HANDFUL OF COUNTIES EAST OF HWY 281 POST-SUNRISE...WHERE NAM
SOUNDINGS INDICATED THAT THE SATURATED LAYER WOULD REMAIN
DEEPER...GENERALLY NEAR/IN EXCESS OF 2500 FT. THAT BEING
SAID...CANNOT COMPLETELY RULE OUT POST-SUNRISE LIGHT DRIZZLE EVEN
IN THE TRI-CITIES AREA WESTWARD GIVEN SUCH A MOIST LOW LEVEL
PROFILE. AS FOR SKY COVER...CONFIDENCE IS CONSIDERABLY HIGHER
TODAY THAT MUCH OF THE CWA WILL SEE AT LEAST A FEW HOURS OF PARTLY
TO MOSTLY SUNNY SKIES AT SOME POINT...BUT EXACTLY WHEN IS STILL
IN QUESTION. HAVE GENERALLY FOLLOWED THE 00Z/06Z NAM SOLUTION OF
KEEPING NEARLY ALL AREAS SOCKED IN WITH STRATUS AND AT LEAST LIGHT
FOG THROUGH THE MORNING HOURS...BUT THEN ERODING FROM WEST-EAST
THROUGH THE AFTERNOON WEARS ON AS EVIDENCED BY THE 900MB RELATIVE
HUMIDITY FIELD. THIS MEANS THAT FAR EASTERN COUNTIES ALONG THE HWY
81 WOULD BE LAST TO SEE ANY CLEARING. AFTER BUSTING HIGH TEMPS BY
10+ DEGREES YESTERDAY DUE TO WIDESPREAD LOW STRATUS...AM IN NO
HURRY TO GO WITH THE WARM END OF AVAILABLE GUIDANCE/MODEL
SOLUTIONS TODAY ESPECIALLY IN EASTERN ZONES. AFTER TRYING VARIOUS
SOLUTIONS ON FOR SIZE...ENDED UP GOING WITH THE 00Z NAM ALMOST
EXACTLY...AS ITS TEMP FIELD SEEMED TO BEST-CAPTURE THE GRADUAL
WEST-EAST CLEARING. THIS RESULTS IN A DECENT RANGE FROM NEAR 80
FAR WEST ...LOW-MID 70S CENTRAL AND UPPER 60S EAST. PLEASE NOTE
THESE VALUES ARE AT LEAST A FEW DEGREES COOLER THAN PREVIOUS
FORECAST ALL AREAS...AND AS MUCH AS 5-8 DEGREES COOLER IN THE
EAST. LIKE YESTERDAY...COULD EASILY FORESEE HIGHS BEING OFF BY 5+
DEGREES DEPENDING ON STRATUS/FOG TRENDS.
TONIGHT...KEPT OUT ALL MENTION OF PRECIP CWA-WIDE...AND AM NOT
EXPECTING A DENSE FOG REPEAT SUCH AS THE ONGOING ONE...BUT DID
INSERT A PATCHY FOG MENTION INTO SEVERAL COUNTIES NORTH OF I-80
AFTER MIDNIGHT IN CLOSEST PROXIMITY TO THE HIGHEST BOUNDARY LAYER
RELATIVE HUMIDITY POOLING IN THE VICINITY OF THE LEADING EDGES OF
THE INVADING COLD FRONT. CLOUD TRENDS TONIGHT ARE CERTAINLY A
CHALLENGE...WITH THE POTENTIAL FOR QUITE AN INCREASE IN STRATUS
TOWARD SUNRISE NEAR THIS BOUNDARY...FOLLOWING WHAT SHOULD BE A
FAIRLY CLEAR EVENING FOR MOST AREAS. ALOFT...THE BIG PICTURE
INVOLVES A LEAD SHORTWAVE TRACKING ACROSS FAR SOUTH CENTRAL
CANADA...WHICH HELPS DRIVE THE SURFACE FRONT INTO THE NORTHERN
CWA...WHILE A TROUGH AXIS SETS UP FROM SOUTHWEST-NORTHEAST ACROSS
KS. KEPT LOWS SIMILAR TO PREVIOUS FORECAST AND A GUIDANCE
BLEND...RANGING FROM LOW-MID 40S NORTHWEST TO UPPER 50S/NEAR 60
SOUTHEAST WHERE DEWPOINTS WILL BE ON THE INCREASE.
WEDNESDAY...OTHER THAN THE LINGERING PATCHY FOG MENTION NORTH IN
THE MORNING...HAVE KEPT OUT ANY OTHER WEATHER MENTION THROUGH
SUNSET...AS THE GENERAL MODEL CONSENSUS IS TO KEEP ANY LIGHT
DAYTIME DRIZZLY PRECIP NORTHEAST OF THE CWA...AND ANY LATE-DAY
CONVECTION ALONG/NEAR THE INVADING COLD FRONT JUST SOUTHEAST OF
THE CWA. THAT BEING SAID...SKY COVER AND TEMP TRENDS ARE AGAIN
QUITE A CHALLENGE...AS QUITE A BIT OF STRATUS SHOULD DOMINATE MUCH
OF THE NORTHWEST CWA WITH MORE SUNSHINE SOUTHEAST.
FORTUNATELY...THE LATEST MODEL RUNS ARE IN REASONABLY GOOD
AGREEMENT REGARDING WHAT WILL CERTAINLY BE A SHARP TEMP
GRADIENT...AND ONLY MADE MINOR ADJUSTMENTS TO PREVIOUS
FORECAST...AIMING FOR A RANGE FROM UPPER 50S FAR NORTH...MID 60S
TO LOW 70S TRI CITIES AREA...AND LOW 80S FAR SOUTHEAST IN THE
HEBRON-BELOIT CORRIDOR. AGAIN THOUGH...5+ DEGREE DEVIATIONS FROM
CURRENT FORECAST ARE VERY POSSIBLE IF NOT LIKELY. PONDERED GOING
WITH A NON-DIURNAL TEMP TREND BEHIND THE FRONT...BUT MODELS ARE
NOT REALLY SHOWING MUCH OF AN AFTERNOON DROP SO STUCK WITH
TRADITIONAL MID-LATE AFTERNOON HIGHS ALL AREAS FOR NOW. THIS COLD
FRONT WILL NOT EXACTLY BLAST THROUGH THE AREA...AND BY SUNSET WILL
JUST BE REACHING FAR SOUTHEAST ZONES...WHILE MOST OF THE CWA WILL
ALREADY BE IN SUSTAINED NORTH WINDS 15-20 MPH.
WEDNESDAY NIGHT IS CLEARLY STILL THE MAIN 12-HOUR WINDOW FOR
POTENTIALLY DECENT RAIN AMOUNTS...AND ACTUALLY RAISED POPS INTO
THE 60-70 PERCENT RANGE ACROSS MUCH OF THE EASTERN CWA...WHILE
LEAVING SOUTHWEST AREAS IN THE 40-50 PERCENT RANGE. IN
SHORT...LARGE SCALE FORCING/MID LEVEL FRONTOGENESIS RAMPS UP AS A
POTENT OPEN WAVE OVER THE CENTRAL ROCKIES MOVES INTO THE CENTRAL
PLAINS...FEATURING A 110+KT 300MB JET STREAK. LEFT THE POP/WEATHER
GRIDS AS ONE 12-HOUR BLOCK FOR NOW...BUT GENERAL THINKING IS THAT
MOST WIDESPREAD COVERAGE OF SHOWERS/STORMS WILL HOLD OFF UNTIL
NEAR/AFTER MIDNIGHT...UNLESS SOME EVENING ACTIVITY FLARES UP IN
THE FAR SOUTH/SOUTHEAST NEAR THE MAIN SURFACE FRONT. LATEST NAM
CONTINUES TO SHOW A HEALTHY CORRIDOR OF MUCAPE 1500+ J/KG IN THE
850-700MB LAYER MAINLY ACROSS THE SOUTHEAST 1/2 OF THE
CWA...DROPPING OFF SHORTLY TO THE NORTHWEST. HOWEVER...WILL KEEP
ISOLATED THUNDER EVEN IN THIS NORTHWEST AREAS. WITH VERY STRONG
DEEP-LAYER SHEAR OF 60+ KNOTS MOVING IN...HAVE INCREASING CONCERNS
THAT AT LEAST MARGINALLY SEVERE HAIL COULD OCCUR IN SOUTHEAST
COUNTIES...AND DESPITE SPC KEEPING THE OFFICIAL DAY2 SLIGHT RISK
OUTLOOK JUST EAST OF THE CWA...AT LEAST FOR NOW...WILL GO AHEAD
AND ADD THIS MENTION TO THE HAZARDOUS WEATHER OUTLOOK AS THESE
STRONG DYNAMICS ARE HARD TO IGNORE. DEPENDING ON HOW WIDESPREAD
STORMS ARE...COULD FORESEE SOME FORTUNATE AREAS RECEIVING IN
EXCESS OF ONE-HALF INCH OF RAIN BUT THIS WILL PROBABLY BE THE
EXCEPTION. ALTHOUGH SOME SNOW OR RAIN/SNOW MIX COULD TRY
DEVELOPING IN WESTERN NEBRASKA IN THE COLDER AIR WELL BEHIND THE
FRONT...LATEST CONSENSUS IS THAT WINTRY PRECIP WED NIGHT SHOULD
FOCUS AT LEAST 50 MILES WEST OF THE CWA...AND THUS WILL KEEP ANY
SNOW MENTION OUT FOR NOW.
THURSDAY...SPLIT THE DAY INTO 6-HOUR BLOCKS...WITH ALL PRECIP GONE
BY THE AFTERNOON HOURS...AND POTENTIALLY EVEN GONE BY MID-MORNING
IN MOST AREAS PER SOME OF THE LATEST TRENDS INCLUDING THE 00Z
ECMWF...WHICH QUICKLY SHUTS OFF THE MID LEVEL LIFT/SATURATION FROM
NORTHWEST-SOUTHEAST. LATER ADJUSTMENTS WILL BE NEEDED...BUT FOR NOW
KEPT 20-40 POPS ACROSS MOST OF THE CWA IN THE MORNING FOR GENERAL
LIGHT RAIN...WITH NO THUNDER MENTION AND STILL NO SNOW
MENTION...ALTHOUGH SUPPOSE A FEW FLURRIES COULD SNEAK INTO FAR
NORTHWEST ZONES JUST BEFORE PRECIP SHUTS OFF FOR GOOD GIVEN
SURFACE TEMPS FORECAST TO DROP INTO THE MID 30S EARLY THURSDAY
MORNING. OTHERWISE...EXPECT INCREASING SUNSHINE AS THE DAY WEARS
ON...ALTHOUGH IT WILL REMAIN QUITE BREEZY WITH SUSTAINED NORTH
WINDS AROUND 20 MPH WITH GUSTS TO AROUND 30 MPH. FOR HIGH
TEMPS...RAW NAM VALUES ARE WELL INTO THE MID 50S ALL AREAS...BUT
WAS NOT WILLING TO GO QUITE THIS WARM YET...AND THUS ONLY MADE
MINOR ADJUSTMENTS TO PREVIOUS FORECAST WITH MOST NEB ZONES TOPPING
OUT UPPER 40S AND KS LOWER 50S.
THURS NIGHT...THIS LOOKS TO BE THE MOST UNEVENTFUL PERIOD OF THE
NEXT 72 HOURS...AS AN EXPANSIVE SURFACE RIDGE AXIS SETTLES INTO
THE REGION FROM THE NORTH...AND ANY LIGHT SNOW ACCUMULATIONS
ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE ENERGY AND LOW LEVEL
UPSLOPE FLOW SHOULD REMAIN NO CLOSER THAN THE NEB/CO/KS BORDER
AREA. DESPITE A POTENTIAL INCREASE IN MID LEVEL CLOUDS...OPTED TO
LOWER LOW TEMPS 2-3 DEGREES FROM PREVIOUS FCST AND POSSIBLY NOT
ENOUGH...BUT AT LEAST GETTING ALL AREAS INTO THE SUB-FREEZING
26-32 RANGE.
LONG TERM...STARTING 12Z FRIDAY...THE LONGWAVE TROUGH ACROSS THE
WEST COAST THIS MORNING WILL BE CENTERED OVER THE PLAINS ON
FRIDAY...WITH SEVERAL EMBEDDED WEAK DISTURBANCES EXPECTED TO HAVE
LITTLE IMPACT IN THE WAY OF CHANCES FOR PRECIP ACROSS THE LOCAL
AREA. SOME DISCREPANCIES EVIDENT WITH THE HANDLING OF THIS TROUGH
AS IT PUSHES EAST LATE IN THE WEEKEND...WITH THE EC QUICKLY BUILDING
A RIDGE OVER THE INTERMOUNTAIN WEST RESULTING IN RISING HEIGHTS
ACROSS THE PLAINS...IN RESPONSE TO THE LONGWAVE TROUGH INTERACTS
WITH A TROPICAL DISTURBANCE OFF THE EASTERN SEABOARD...AND THE
LATEST GFS DEPICTING A MORE ZONAL WEST TO NORTHWEST FLOW ACROSS THE
REGION BY EARLY NEXT WEEK...AS THE AFOREMENTIONED TROPICAL
DISTURBANCE INSTEAD TRACKS OUT INTO THE OPEN ATLANTIC. EITHER
WAY...THIS APPEARS TO BE A DRY PATTERN FOR THE LOCAL AREA AS THERE
ARE NO SIGNIFICANT FEATURES FORECAST TO IMPACT THE AREA IN THE
DIVERGENT UPPER LEVEL FLOW PATTERNS DEPICTED AMONGST THE LONG TERM
MODELS. THEREFORE...EXPECT DRY CONDITIONS...WITH CONTINUED
UNSEASONABLY COOL TEMPERATURES...TO AT LEAST START THE EXTENDED
PERIODS...WITH TEMPERATURES POSSIBLY WARMING CLOSER TO
CLIMATOLOGY...WHILE REMAINING DRY...EARLY NEXT WEEK IF THE EC
SOLUTION ENDS UP BEING CORRECT. HOWEVER...DUE TO THE UNCERTAINTY OF
THE SYNOPTIC SCALE PATTERN EARLY NEXT WEEK...STUCK WITH ALLBLEND
MODEL SOLUTION THIS MORNING...WITH NO NOTABLE TWEAKS TO SPEAK OF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
633 AM CDT TUE OCT 23 2012
.UPDATE...
.AVIATION...
LIFR/IFR CIGS AND VSBY IMPROVE TO VFR FROM WEST TO EAST BETWEEN 15Z
AND 18Z ALONG AND WEST OF HIGHWAY 83. EAST OF HIGHWAY 83...LIFR/IFR
CIGS AND VIS IMPROVE TO IFR/MVFR CIGS AROUND 18Z AND THEN VFR BY 21Z.
A COLD FRONT WILL DROP INTO THE FCST AREA TONIGHT. A NARROW AREA
OF MVFR/IFR CIGS MAY DEVELOP POSSIBLE AFTER 09Z TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT TUE OCT 23 2012/
DISCUSSION...
PRIMARY FOCUS THROUGH THIS FORECAST PERIOD IS FOG AND TEMPERATURES
TODAY...THEN RAIN/SNOW CHANCES FOCUSED ON WEDNESDAY NIGHT AND
THURSDAY. BEYOND THAT...COLDER TEMPERATURES FOR THE LATTER HALF OF
THE WEEK.
WATER VAPOR IMAGERY THIS MORNING SHOWS A LONGWAVE TROUGH OVER THE
EASTERN PACIFIC INTO THE WESTERN CONUS...WITH RIDGING ACROSS THE
GREAT LAKES. A WEAK SHORTWAVE TROUGH WAS OBSERVED ACROSS THE
NORTHERN PLAINS...WITH SUBSIDENCE ALOFT ACROSS NEBRASKA HELPING TO
KEEP THE MID-LEVELS DRY THIS MORNING. SEVERAL OTHER SHORTWAVES OF
NOTE WITHIN THE LONGWAVE TROUGH WERE ONE OVER NEVADA...WITH
ANOTHER STILL OVER THE OCEAN. AT THE SURFACE...SOUTH TO SOUTHEAST
FLOW WAS BRINGING IN LOW LEVEL MOISTURE AND WITH THE DRY AIR
ALOFT...FOG HAS DEVELOPED ACROSS ALMOST ALL OF NEBRASKA BY 08Z.
THIS HAS KEPT TEMPERATURES UP...WITH READINGS IN THE MID 40S TO
LOW 50S. THE OTHER FEATURE TO NOTE IS LOW PRESSURE ON THE LEE SIDE
OF THE ROCKIES.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ACCORDING TO THE RUC AND THE NAM...FOG SHOULD SLOWLY DISSIPATE
FROM THE WEST...BUT PLACES OVER THE EASTERN PART OF THE FORECAST
AREA...EAST OF HIGHWAY 83 COULD SEE THE FOG LINGER INTO THE EARLY
AFTERNOON HOURS. THE FOG WILL HAVE A BIG IMPACT ON HIGH
TEMPERATURES TODAY SO IF IT FAILS TO DISSIPATE BY 18Z OR
19Z...TEMPERATURES COULD BE UP TO 10 DEGREES TO WARM IN PLACES.
DAY SHIFT WILL NEED TO MONITOR TRENDS IN CASE TEMPERATURE FORECAST
NEEDS TO BE MODIFIED. 850MB TEMPERATURES WILL INCREASE TODAY
/BETWEEN 15C AND 23C/ DUE TO WARM AIR ADVECTION AHEAD OF THE AREA
OF LOW PRESSURE TO THE WEST. ASSUMING SKIES CLEAR...TEMPERATURES
SHOULD WARM CONSIDERABLY...WITH LOW 80S POSSIBLE ACROSS SOUTHWEST
NEBRASKA. THE SHORTWAVE TROUGH OVER NEVADA WILL LIFT INTO MONTANA
TODAY...WHICH WILL GIVE THE FRONT TO THE WEST A BIT OF A PUSH
EASTWARD. THE NAM PUSHES A DRYLINE ACROSS THE SANDHILLS THIS
AFTERNOON...WHICH COULD DROP DEWPOINTS INTO THE LOW 30S. GOING
SOUTH...DEWPOINTS WILL DROP INTO THE 30S AS WELL AS THE DRYLINE
PROGRESSES EAST. THIS WILL PROMOTE DEEP MIXING TO NEAR 700MB.
WINDS THROUGH THE MIXED LAYER WILL BE STRONGEST ACROSS NORTHWEST
NEBRASKA...WHERE GUSTS TO 30 MPH LOOK POSSIBLE THIS AFTERNOON.
GOING SOUTH...WINDS ALOFT DECREASE SO WINDY CONDITIONS ARE NOT
EXPECTED. WITH THE TEMPERATURES EXPECTED TODAY...LOWEST RELATIVE
HUMIDITY WILL BE ACROSS SOUTHWEST NEBRASKA...WITH VALUES DROPPING
TO THE MID 20S WHERE WINDS WILL BE STRONG. AS IS
FORECAST...CRITICAL FIRE WEATHER CONDITIONS WILL NOT BE
MET...ALTHOUGH MARGINAL CONDITIONS WILL BE LIKELY IN A FEW
LOCATIONS FOR AT LEAST A FEW HOURS TODAY. AGAIN...CLOUD COVER
COULD HAMPER THIS FROM OCCURRING...SO WILL NEED TO MONITOR TRENDS
FOR POTENTIAL FIRE WEATHER ISSUES TODAY.
THE MONTANA WAVE LIFTS INTO CANADA TONIGHT...WITH A COLD FRONT TO
THE WEST PROGRESSING SOUTHEAST ACROSS NEBRASKA TONIGHT. BY MID
MORNING WEDNESDAY SHOULD BE THROUGH MOST OF THE FORECAST AREA.
COULD AGAIN SEE SOME FOG WEDNESDAY MORNING...BUT THIS SHOULD BE
CONFINED TO AREAS RIGHT ALONG AND BEHIND THE FRONT WHERE LOW LEVEL
MOISTURE POOLS. A THE SHORTWAVE TROUGH WILL ALSO MOVE ONLAND
TONIGHT...WHICH WILL THEN PROGRESS ACROSS UTAH AND INTO COLORADO
ON WEDNESDAY. AS THIS IS ONGOING...A 700MB TROUGH WILL PASS ACROSS
THE NORTHERN AND CENTRAL PLAINS WEDNESDAY AND WEDNESDAY NIGHT.
MODELS ARE SHOWING GOOD FRONTOGENETICAL FORCING...WHILE THE
LOCATION OF THE UPPER LEVEL JET STREAK PUTS NORTHWEST NEBRASKA IN
AN AREA OF GOOD LARGE-SCALE LIFT. THE SIGNAL HAS BEEN QUITE
CONSISTENT IN TIMING AND LOCATION OF THE BEST FORCING FROM THE
DIFFERENT MODELS OVER THE PAST FEW DAYS SO CONFIDENCE HAS
INCREASED IN GETTING PRECIPITATION ACROSS THE FORECAST AREA. IT
MAY TAKE A BIT OF TIME TO SATURATE THE LOW LEVELS...SO ONLY BEGAN
CHANCES FOR RAIN IN THE FAR NORTHERN PARTS OF SHERIDAN AND CHERRY
COUNTIES WEDNESDAY MORNING AND SLOWLY EXPANDING SOUTH THROUGH THE
AFTERNOON. WEDNESDAY EVENING LOOKS TO SEE THE BEST CHANCES FOR
PRECIPITATION IN AREAS NORTHWEST OF AN IMPERIAL TO VALENTINE
LINE...AND THOUGH DO HAVE RAIN CHANCES TO THE EAST...LOWERED
CHANCES BEFORE MIDNIGHT AS TOO MUCH DRY AIR LOOKS TO EXIST IN
THESE AREAS. THE PRECIPITATION AREA DOES SHIFT TO THE SOUTH AND
EAST AFTER MIDNIGHT...BUT AS THE PRIMARY SHORTWAVE TROUGH EXITS
THE AREA BY 12Z THURSDAY MORNING...LARGE-SCALE FORCING WILL
DETERIORATE SO CHANCES HAVE LOWERED FOR THURSDAY. BY LATE
AFTERNOON THURSDAY...EXPECT THE FORECAST AREA TO SEE PRIMARILY DRY
CONDITIONS. THERE IS ANOTHER SHORTWAVE THAT WILL ROUND THE
LONGWAVE TROUGH LATER THURSDAY AND THURSDAY NIGHT...BUT THE TREND
CONTINUES TO GO SOUTH SO PRECIPITATION CHANCES LOOK TO STAY TO THE
SOUTH. TEMPERATURE PROFILES CONTINUE TO SHOW THE PRECIPITATION
TYPE BEGIN AS RAIN...BUT CHANGE OVER TO A RAIN/SNOW MIX WITH SNOW
BECOMING THE DOMINANT TYPE ACROSS THE NORTHWEST AREAS AFTER
MIDNIGHT WEDNESDAY NIGHT. HAVE RAIN OR SNOW IN THE FORECAST ACROSS
THE ENTIRE AREA FOR THURSDAY MORNING AS THE PROFILES HUG 0C IN THE
LOWEST LEVELS ABOVE THE SURFACE. DON/T EXPECT MUCH ACCUMULATION OF
SNOW...WITH PRECIPITATION ACCUMULATIONS UP TO A THIRD OF AN INCH
MAINLY NORTH OF INTERSTATE 80.
LONG TERM...FRIDAY THROUGH MONDAY
COLD TEMPERATURES WILL BE THE HIGHLIGHT FOR THE WEEKEND AS HIGHS
WILL BE HARD PRESSED TO MAKE IT OUT OF THE 30S AND 40S FOR FRIDAY
AND SATURDAY. LOWS ALSO WILL BE QUITE COLD...ALTHOUGH THE 23.00Z
MODEL SOLUTIONS ARE A BIT WARMER FOR BOTH FRIDAY AND SATURDAY
NIGHTS WITH THE SURFACE HIGH NOW LOOKING TO STAY OFF TO THE EAST
OF THE FORECAST AREA. LOWS SHOULD STILL EASILY DROP INTO THE
20S...WITH TEENS POSSIBLE FRIDAY NIGHT.
THE TREND NOW LOOKS FOR WARMER CONDITIONS GOING INTO NEXT WEEK AS
RIDGING BUILDS OVER THE WESTERN HALF OF THE COUNTRY. THIS WILL
BRING MILD TEMPERATURES BACK INTO THE CENTRAL PLAINS WITH 850MB
TEMPERATURES WARMING INTO THE TEENS AGAIN BY MONDAY...COMPARED TO
READINGS BELOW 0C WHICH WILL BE EXPERIENCED FRIDAY AND SATURDAY.
THE FORECAST IS DRY THROUGH THIS PERIOD AS THE LONGWAVE TROUGH
WILL PUSH THE MOISTURE ACROSS THE PLAINS WELL TO THE
SOUTHEAST.
AVIATION...
LIFR/IFR CIGS AND VSBY IMPROVE TO VFR FROM WEST TO EAST BETWEEN 15Z
AND 18Z ALONG AND WEST OF HIGHWAY 83. EAST OF HIGHWAY 83...LIFR/IFR
CIGS AND VIS IMPROVE TO IFR/MVFR CIGS AROUND 18Z AND THEN VFR BY 21Z.
A COLD FRONT WILL DROP INTO THE FCST AREA TONIGHT WITH MVFR/IFR CIGS
POSSIBLE AFTER 06Z TUESDAY NIGHT.
FIRE WEATHER...
POTENTIAL RED FLAG CONDITIONS WILL BE MONITORED ACROSS WRN NEB THIS
AFTERNOON DEPENDING ON THE PROGRESS OF A CLEARING LINE FCST TO
DEVELOP ACROSS THE PANHANDLE THIS MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CDT TUE OCT 23 2012
.AVIATION...12Z KGRI TAF...STRATUS CONTINUES TO COVER A GOOD
PORTION OF THE CENTRAL PLAINS THIS MORNING WITH LIFR/IFR CIGS
MIXED THROUGHOUT AREAS OF FG/BR/-DZ. EXPECT THE LIFR/IFR
CONDITIONS WILL PERSIST THROUGH AROUND 23/16Z...WHEN CIGS AND
VISIBILITIES ARE EXPECTED TO BEGIN TO IMPROVE MORE SUBSTANTIALLY
AS WINDS BEGIN TO INCREASE OUT OF THE SOUTH AND SOME MIXING ALLOWS
FOR CIGS/VSBYS TO BEGIN TO LIFT/IMPROVE. THIS IMPROVING TREND IS
EXPECTED TO CONTINUE THROUGH EARLY AFTERNOON...WITH A RETURN TO
VFR CIGS/VSBYS EXPECTED BY 23/19Z...AS INDICATED BY LATEST SHORT
TERM GUIDANCE.
&&
.PREV DISCUSSION... /ISSUED 516 AM CDT TUE OCT 23 2012/
SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER NIGHT...AND ANOTHER
SET OF SEVERAL TRICKY FORECAST ELEMENTS DURING THE NEXT 72
HOURS...NAMELY HIGH TEMPS AND PRECIP/FOG TRENDS...AND WHETHER ANY
STORMS WED NIGHT MIGHT GO SEVERE.
09Z OBJECTIVE SURFACE ANALYSIS CONFIRMS THAT THE ENTIRE CWA LIES
NORTH OF A QUASI-STATIONARY BOUNDARY SNAKING EAST-NORTHEAST ACROSS
SOUTHERN/EASTERN KANSAS AND EXTENDING FROM A WEAK 1003MB LOW IN
SOUTHEAST CO. BREEZES ACROSS THE CWA RANGE FROM LIGHT/VARIABLE TO
LIGHT EASTERLY...WITH LITTLE IF ANY TEMP/DEWPOINT DEPRESSION WITH
VALUES RANGING GENERALLY 47-53 ALL AREAS. AS EXPECTED 24 HOURS
AGO...VARYING DEGREES OF FOG HAVE SETTLED IN OVERNIGHT...WITH THE
ENTIRE CWA SEEING NO BETTER THAN 2-3 MILE VISIBILITY...AND THE MOST
CONCENTRATED ZONE OF DENSE FOG 1/4 MILE OR LOWER VSBY FOCUSED FROM
I-80 SOUTHWARD INTO KANSAS PER AUTOMATED OBS AND WEBCAMS. LIGHT
DRIZZLE HAS SEEMINGLY BEEN OFF AND ON OVERNIGHT...BUT IS LIKELY
STILL PRESENT IN MUCH OF THE CWA. ALOFT...WATER VAPOR SATELLITE
IMAGERY AND LATEST MODEL DATA CONFIRM BROAD WEST- SOUTHWEST FLOW
OVER THE CENTRAL PLAINS...WHICH IS POSITIONED DOWNSTREAM FROM A
LARGE SCALE TROUGH ANCHORED ACROSS THE PACIFIC NORTHWEST WITH A
CLOSED 500MB LOW OFF THE WASHINGTON STATE COAST. CLOSER TO
HOME...A SMALL SCALE SHORTWAVE TROUGH IS CURRENTLY DEPARTING
EASTWARD ACROSS MO...PROMOTING CONSIDERABLE ELEVATED THUNDERSTORM
ACTIVITY IN THAT AREA.
STARTING OFF EARLY THIS MORNING...THE MOST IMMEDIATE ISSUE IS THE
ONGOING CWA-WIDE DENSE FOG ADVISORY VALID THROUGH 15Z...AND WILL
LET IT RIDE AS-IS FOR NOW. TECHNICALLY SPEAKING...AUTOMATED OBS
SUGGEST THAT SO FAR THE MAJORITY OF ANY LOCALLY DENSE FOG HAS BEEN
CONFINED TO AREAS SOUTH OF THE I-80 CORRIDOR...BUT VARIOUS SHORT
TERM VISIBILITY GUIDANCE FROM THE HRRR/SREF SUGGEST THAT A
NORTHWARD EXPANSION OF DENSE FOG IS QUITE POSSIBLE YET THIS
MORNING...AND AM NOT ABOUT TO CANCEL ANY OF THIS ADVISORY UNTIL
TRENDS CAN BE MONITORED FOR AT LEAST A FEW MORE HOURS. IN
FACT...AM STARTING TO EVEN WONDER IF THE 15Z EXPIRATION TIME WILL
BE LONG ENOUGH...WITH BOTH THE HRRR AND HOURLY GFS LAMP GUIDANCE
SUGGESTING THAT SOME AREAS COULD REMAIN RATHER SOCKED IN UNTIL AT
LEAST 16Z-17Z. DAY SHIFT WILL HAVE TO KEEP AN EYE ON THE POSSIBLE
NEED FOR AN EXTENSION. AS FOR THE OFF AND ON LIGHT DRIZZLE SUCH AS
OBSERVED HERE AT THE WFO TONIGHT...HAVE IT MENTIONED CWA-WIDE
THROUGH 12Z...BUT HAVE THEN ATTEMPTED TO CONFINE IT TO ONLY A
HANDFUL OF COUNTIES EAST OF HWY 281 POST-SUNRISE...WHERE NAM
SOUNDINGS INDICATED THAT THE SATURATED LAYER WOULD REMAIN
DEEPER...GENERALLY NEAR/IN EXCESS OF 2500 FT. THAT BEING
SAID...CANNOT COMPLETELY RULE OUT POST-SUNRISE LIGHT DRIZZLE EVEN
IN THE TRI-CITIES AREA WESTWARD GIVEN SUCH A MOIST LOW LEVEL
PROFILE. AS FOR SKY COVER...CONFIDENCE IS CONSIDERABLY HIGHER
TODAY THAT MUCH OF THE CWA WILL SEE AT LEAST A FEW HOURS OF PARTLY
TO MOSTLY SUNNY SKIES AT SOME POINT...BUT EXACTLY WHEN IS STILL
IN QUESTION. HAVE GENERALLY FOLLOWED THE 00Z/06Z NAM SOLUTION OF
KEEPING NEARLY ALL AREAS SOCKED IN WITH STRATUS AND AT LEAST LIGHT
FOG THROUGH THE MORNING HOURS...BUT THEN ERODING FROM WEST-EAST
THROUGH THE AFTERNOON WEARS ON AS EVIDENCED BY THE 900MB RELATIVE
HUMIDITY FIELD. THIS MEANS THAT FAR EASTERN COUNTIES ALONG THE HWY
81 WOULD BE LAST TO SEE ANY CLEARING. AFTER BUSTING HIGH TEMPS BY
10+ DEGREES YESTERDAY DUE TO WIDESPREAD LOW STRATUS...AM IN NO
HURRY TO GO WITH THE WARM END OF AVAILABLE GUIDANCE/MODEL
SOLUTIONS TODAY ESPECIALLY IN EASTERN ZONES. AFTER TRYING VARIOUS
SOLUTIONS ON FOR SIZE...ENDED UP GOING WITH THE 00Z NAM ALMOST
EXACTLY...AS ITS TEMP FIELD SEEMED TO BEST-CAPTURE THE GRADUAL
WEST-EAST CLEARING. THIS RESULTS IN A DECENT RANGE FROM NEAR 80
FAR WEST ...LOW-MID 70S CENTRAL AND UPPER 60S EAST. PLEASE NOTE
THESE VALUES ARE AT LEAST A FEW DEGREES COOLER THAN PREVIOUS
FORECAST ALL AREAS...AND AS MUCH AS 5-8 DEGREES COOLER IN THE
EAST. LIKE YESTERDAY...COULD EASILY FORESEE HIGHS BEING OFF BY 5+
DEGREES DEPENDING ON STRATUS/FOG TRENDS.
TONIGHT...KEPT OUT ALL MENTION OF PRECIP CWA-WIDE...AND AM NOT
EXPECTING A DENSE FOG REPEAT SUCH AS THE ONGOING ONE...BUT DID
INSERT A PATCHY FOG MENTION INTO SEVERAL COUNTIES NORTH OF I-80
AFTER MIDNIGHT IN CLOSEST PROXIMITY TO THE HIGHEST BOUNDARY LAYER
RELATIVE HUMIDITY POOLING IN THE VICINITY OF THE LEADING EDGES OF
THE INVADING COLD FRONT. CLOUD TRENDS TONIGHT ARE CERTAINLY A
CHALLENGE...WITH THE POTENTIAL FOR QUITE AN INCREASE IN STRATUS
TOWARD SUNRISE NEAR THIS BOUNDARY...FOLLOWING WHAT SHOULD BE A
FAIRLY CLEAR EVENING FOR MOST AREAS. ALOFT...THE BIG PICTURE
INVOLVES A LEAD SHORTWAVE TRACKING ACROSS FAR SOUTH CENTRAL
CANADA...WHICH HELPS DRIVE THE SURFACE FRONT INTO THE NORTHERN
CWA...WHILE A TROUGH AXIS SETS UP FROM SOUTHWEST-NORTHEAST ACROSS
KS. KEPT LOWS SIMILAR TO PREVIOUS FORECAST AND A GUIDANCE
BLEND...RANGING FROM LOW-MID 40S NORTHWEST TO UPPER 50S/NEAR 60
SOUTHEAST WHERE DEWPOINTS WILL BE ON THE INCREASE.
WEDNESDAY...OTHER THAN THE LINGERING PATCHY FOG MENTION NORTH IN
THE MORNING...HAVE KEPT OUT ANY OTHER WEATHER MENTION THROUGH
SUNSET...AS THE GENERAL MODEL CONSENSUS IS TO KEEP ANY LIGHT
DAYTIME DRIZZLY PRECIP NORTHEAST OF THE CWA...AND ANY LATE-DAY
CONVECTION ALONG/NEAR THE INVADING COLD FRONT JUST SOUTHEAST OF
THE CWA. THAT BEING SAID...SKY COVER AND TEMP TRENDS ARE AGAIN
QUITE A CHALLENGE...AS QUITE A BIT OF STRATUS SHOULD DOMINATE MUCH
OF THE NORTHWEST CWA WITH MORE SUNSHINE SOUTHEAST.
FORTUNATELY...THE LATEST MODEL RUNS ARE IN REASONABLY GOOD
AGREEMENT REGARDING WHAT WILL CERTAINLY BE A SHARP TEMP
GRADIENT...AND ONLY MADE MINOR ADJUSTMENTS TO PREVIOUS
FORECAST...AIMING FOR A RANGE FROM UPPER 50S FAR NORTH...MID 60S
TO LOW 70S TRI CITIES AREA...AND LOW 80S FAR SOUTHEAST IN THE
HEBRON-BELOIT CORRIDOR. AGAIN THOUGH...5+ DEGREE DEVIATIONS FROM
CURRENT FORECAST ARE VERY POSSIBLE IF NOT LIKELY. PONDERED GOING
WITH A NON-DIURNAL TEMP TREND BEHIND THE FRONT...BUT MODELS ARE
NOT REALLY SHOWING MUCH OF AN AFTERNOON DROP SO STUCK WITH
TRADITIONAL MID-LATE AFTERNOON HIGHS ALL AREAS FOR NOW. THIS COLD
FRONT WILL NOT EXACTLY BLAST THROUGH THE AREA...AND BY SUNSET WILL
JUST BE REACHING FAR SOUTHEAST ZONES...WHILE MOST OF THE CWA WILL
ALREADY BE IN SUSTAINED NORTH WINDS 15-20 MPH.
WEDNESDAY NIGHT IS CLEARLY STILL THE MAIN 12-HOUR WINDOW FOR
POTENTIALLY DECENT RAIN AMOUNTS...AND ACTUALLY RAISED POPS INTO
THE 60-70 PERCENT RANGE ACROSS MUCH OF THE EASTERN CWA...WHILE
LEAVING SOUTHWEST AREAS IN THE 40-50 PERCENT RANGE. IN
SHORT...LARGE SCALE FORCING/MID LEVEL FRONTOGENESIS RAMPS UP AS A
POTENT OPEN WAVE OVER THE CENTRAL ROCKIES MOVES INTO THE CENTRAL
PLAINS...FEATURING A 110+KT 300MB JET STREAK. LEFT THE POP/WEATHER
GRIDS AS ONE 12-HOUR BLOCK FOR NOW...BUT GENERAL THINKING IS THAT
MOST WIDESPREAD COVERAGE OF SHOWERS/STORMS WILL HOLD OFF UNTIL
NEAR/AFTER MIDNIGHT...UNLESS SOME EVENING ACTIVITY FLARES UP IN
THE FAR SOUTH/SOUTHEAST NEAR THE MAIN SURFACE FRONT. LATEST NAM
CONTINUES TO SHOW A HEALTHY CORRIDOR OF MUCAPE 1500+ J/KG IN THE
850-700MB LAYER MAINLY ACROSS THE SOUTHEAST 1/2 OF THE
CWA...DROPPING OFF SHORTLY TO THE NORTHWEST. HOWEVER...WILL KEEP
ISOLATED THUNDER EVEN IN THIS NORTHWEST AREAS. WITH VERY STRONG
DEEP-LAYER SHEAR OF 60+ KNOTS MOVING IN...HAVE INCREASING CONCERNS
THAT AT LEAST MARGINALLY SEVERE HAIL COULD OCCUR IN SOUTHEAST
COUNTIES...AND DESPITE SPC KEEPING THE OFFICIAL DAY2 SLIGHT RISK
OUTLOOK JUST EAST OF THE CWA...AT LEAST FOR NOW...WILL GO AHEAD
AND ADD THIS MENTION TO THE HAZARDOUS WEATHER OUTLOOK AS THESE
STRONG DYNAMICS ARE HARD TO IGNORE. DEPENDING ON HOW WIDESPREAD
STORMS ARE...COULD FORESEE SOME FORTUNATE AREAS RECEIVING IN
EXCESS OF ONE-HALF INCH OF RAIN BUT THIS WILL PROBABLY BE THE
EXCEPTION. ALTHOUGH SOME SNOW OR RAIN/SNOW MIX COULD TRY
DEVELOPING IN WESTERN NEBRASKA IN THE COLDER AIR WELL BEHIND THE
FRONT...LATEST CONSENSUS IS THAT WINTRY PRECIP WED NIGHT SHOULD
FOCUS AT LEAST 50 MILES WEST OF THE CWA...AND THUS WILL KEEP ANY
SNOW MENTION OUT FOR NOW.
THURSDAY...SPLIT THE DAY INTO 6-HOUR BLOCKS...WITH ALL PRECIP GONE
BY THE AFTERNOON HOURS...AND POTENTIALLY EVEN GONE BY MID-MORNING
IN MOST AREAS PER SOME OF THE LATEST TRENDS INCLUDING THE 00Z
ECMWF...WHICH QUICKLY SHUTS OFF THE MID LEVEL LIFT/SATURATION FROM
NORTHWEST-SOUTHEAST. LATER ADJUSTMENTS WILL BE NEEDED...BUT FOR NOW
KEPT 20-40 POPS ACROSS MOST OF THE CWA IN THE MORNING FOR GENERAL
LIGHT RAIN...WITH NO THUNDER MENTION AND STILL NO SNOW
MENTION...ALTHOUGH SUPPOSE A FEW FLURRIES COULD SNEAK INTO FAR
NORTHWEST ZONES JUST BEFORE PRECIP SHUTS OFF FOR GOOD GIVEN
SURFACE TEMPS FORECAST TO DROP INTO THE MID 30S EARLY THURSDAY
MORNING. OTHERWISE...EXPECT INCREASING SUNSHINE AS THE DAY WEARS
ON...ALTHOUGH IT WILL REMAIN QUITE BREEZY WITH SUSTAINED NORTH
WINDS AROUND 20 MPH WITH GUSTS TO AROUND 30 MPH. FOR HIGH
TEMPS...RAW NAM VALUES ARE WELL INTO THE MID 50S ALL AREAS...BUT
WAS NOT WILLING TO GO QUITE THIS WARM YET...AND THUS ONLY MADE
MINOR ADJUSTMENTS TO PREVIOUS FORECAST WITH MOST NEB ZONES TOPPING
OUT UPPER 40S AND KS LOWER 50S.
THURS NIGHT...THIS LOOKS TO BE THE MOST UNEVENTFUL PERIOD OF THE
NEXT 72 HOURS...AS AN EXPANSIVE SURFACE RIDGE AXIS SETTLES INTO
THE REGION FROM THE NORTH...AND ANY LIGHT SNOW ACCUMULATIONS
ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE ENERGY AND LOW LEVEL
UPSLOPE FLOW SHOULD REMAIN NO CLOSER THAN THE NEB/CO/KS BORDER
AREA. DESPITE A POTENTIAL INCREASE IN MID LEVEL CLOUDS...OPTED TO
LOWER LOW TEMPS 2-3 DEGREES FROM PREVIOUS FCST AND POSSIBLY NOT
ENOUGH...BUT AT LEAST GETTING ALL AREAS INTO THE SUB-FREEZING
26-32 RANGE.
LONG TERM...STARTING 12Z FRIDAY...THE LONGWAVE TROUGH ACROSS THE
WEST COAST THIS MORNING WILL BE CENTERED OVER THE PLAINS ON
FRIDAY...WITH SEVERAL EMBEDDED WEAK DISTURBANCES EXPECTED TO HAVE
LITTLE IMPACT IN THE WAY OF CHANCES FOR PRECIP ACROSS THE LOCAL
AREA. SOME DISCREPANCIES EVIDENT WITH THE HANDLING OF THIS TROUGH
AS IT PUSHES EAST LATE IN THE WEEKEND...WITH THE EC QUICKLY BUILDING
A RIDGE OVER THE INTERMOUNTAIN WEST RESULTING IN RISING HEIGHTS
ACROSS THE PLAINS...IN RESPONSE TO THE LONGWAVE TROUGH INTERACTS
WITH A TROPICAL DISTURBANCE OFF THE EASTERN SEABOARD...AND THE
LATEST GFS DEPICTING A MORE ZONAL WEST TO NORTHWEST FLOW ACROSS THE
REGION BY EARLY NEXT WEEK...AS THE AFOREMENTIONED TROPICAL
DISTURBANCE INSTEAD TRACKS OUT INTO THE OPEN ATLANTIC. EITHER
WAY...THIS APPEARS TO BE A DRY PATTERN FOR THE LOCAL AREA AS THERE
ARE NO SIGNIFICANT FEATURES FORECAST TO IMPACT THE AREA IN THE
DIVERGENT UPPER LEVEL FLOW PATTERNS DEPICTED AMONGST THE LONG TERM
MODELS. THEREFORE...EXPECT DRY CONDITIONS...WITH CONTINUED
UNSEASONABLY COOL TEMPERATURES...TO AT LEAST START THE EXTENDED
PERIODS...WITH TEMPERATURES POSSIBLY WARMING CLOSER TO
CLIMATOLOGY...WHILE REMAINING DRY...EARLY NEXT WEEK IF THE EC
SOLUTION ENDS UP BEING CORRECT. HOWEVER...DUE TO THE UNCERTAINTY OF
THE SYNOPTIC SCALE PATTERN EARLY NEXT WEEK...STUCK WITH ALLBLEND
MODEL SOLUTION THIS MORNING...WITH NO NOTABLE TWEAKS TO SPEAK OF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ039>041-
046>049-060>064-072>077-082>087.
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ005>007-
017>019.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
516 AM CDT TUE OCT 23 2012
.SHORT TERM...THROUGH THURSDAY NIGHT. ANOTHER NIGHT...AND ANOTHER
SET OF SEVERAL TRICKY FORECAST ELEMENTS DURING THE NEXT 72
HOURS...NAMELY HIGH TEMPS AND PRECIP/FOG TRENDS...AND WHETHER ANY
STORMS WED NIGHT MIGHT GO SEVERE.
09Z OBJECTIVE SURFACE ANALYSIS CONFIRMS THAT THE ENTIRE CWA LIES
NORTH OF A QUASI-STATIONARY BOUNDARY SNAKING EAST-NORTHEAST ACROSS
SOUTHERN/EASTERN KANSAS AND EXTENDING FROM A WEAK 1003MB LOW IN
SOUTHEAST CO. BREEZES ACROSS THE CWA RANGE FROM LIGHT/VARIABLE TO
LIGHT EASTERLY...WITH LITTLE IF ANY TEMP/DEWPOINT DEPRESSION WITH
VALUES RANGING GENERALLY 47-53 ALL AREAS. AS EXPECTED 24 HOURS
AGO...VARYING DEGREES OF FOG HAVE SETTLED IN OVERNIGHT...WITH THE
ENTIRE CWA SEEING NO BETTER THAN 2-3 MILE VISIBILITY...AND THE MOST
CONCENTRATED ZONE OF DENSE FOG 1/4 MILE OR LOWER VSBY FOCUSED FROM
I-80 SOUTHWARD INTO KANSAS PER AUTOMATED OBS AND WEBCAMS. LIGHT
DRIZZLE HAS SEEMINGLY BEEN OFF AND ON OVERNIGHT...BUT IS LIKELY
STILL PRESENT IN MUCH OF THE CWA. ALOFT...WATER VAPOR SATELLITE
IMAGERY AND LATEST MODEL DATA CONFIRM BROAD WEST- SOUTHWEST FLOW
OVER THE CENTRAL PLAINS...WHICH IS POSITIONED DOWNSTREAM FROM A
LARGE SCALE TROUGH ANCHORED ACROSS THE PACIFIC NORTHWEST WITH A
CLOSED 500MB LOW OFF THE WASHINGTON STATE COAST. CLOSER TO
HOME...A SMALL SCALE SHORTWAVE TROUGH IS CURRENTLY DEPARTING
EASTWARD ACROSS MO...PROMOTING CONSIDERABLE ELEVATED THUNDERSTORM
ACTIVITY IN THAT AREA.
STARTING OFF EARLY THIS MORNING...THE MOST IMMEDIATE ISSUE IS THE
ONGOING CWA-WIDE DENSE FOG ADVISORY VALID THROUGH 15Z...AND WILL
LET IT RIDE AS-IS FOR NOW. TECHNICALLY SPEAKING...AUTOMATED OBS
SUGGEST THAT SO FAR THE MAJORITY OF ANY LOCALLY DENSE FOG HAS BEEN
CONFINED TO AREAS SOUTH OF THE I-80 CORRIDOR...BUT VARIOUS SHORT
TERM VISIBILITY GUIDANCE FROM THE HRRR/SREF SUGGEST THAT A
NORTHWARD EXPANSION OF DENSE FOG IS QUITE POSSIBLE YET THIS
MORNING...AND AM NOT ABOUT TO CANCEL ANY OF THIS ADVISORY UNTIL
TRENDS CAN BE MONITORED FOR AT LEAST A FEW MORE HOURS. IN
FACT...AM STARTING TO EVEN WONDER IF THE 15Z EXPIRATION TIME WILL
BE LONG ENOUGH...WITH BOTH THE HRRR AND HOURLY GFS LAMP GUIDANCE
SUGGESTING THAT SOME AREAS COULD REMAIN RATHER SOCKED IN UNTIL AT
LEAST 16Z-17Z. DAY SHIFT WILL HAVE TO KEEP AN EYE ON THE POSSIBLE
NEED FOR AN EXTENSION. AS FOR THE OFF AND ON LIGHT DRIZZLE SUCH AS
OBSERVED HERE AT THE WFO TONIGHT...HAVE IT MENTIONED CWA-WIDE
THROUGH 12Z...BUT HAVE THEN ATTEMPTED TO CONFINE IT TO ONLY A
HANDFUL OF COUNTIES EAST OF HWY 281 POST-SUNRISE...WHERE NAM
SOUNDINGS INDICATED THAT THE SATURATED LAYER WOULD REMAIN
DEEPER...GENERALLY NEAR/IN EXCESS OF 2500 FT. THAT BEING
SAID...CANNOT COMPLETELY RULE OUT POST-SUNRISE LIGHT DRIZZLE EVEN
IN THE TRI-CITIES AREA WESTWARD GIVEN SUCH A MOIST LOW LEVEL
PROFILE. AS FOR SKY COVER...CONFIDENCE IS CONSIDERABLY HIGHER
TODAY THAT MUCH OF THE CWA WILL SEE AT LEAST A FEW HOURS OF PARTLY
TO MOSTLY SUNNY SKIES AT SOME POINT...BUT EXACTLY WHEN IS STILL
IN QUESTION. HAVE GENERALLY FOLLOWED THE 00Z/06Z NAM SOLUTION OF
KEEPING NEARLY ALL AREAS SOCKED IN WITH STRATUS AND AT LEAST LIGHT
FOG THROUGH THE MORNING HOURS...BUT THEN ERODING FROM WEST-EAST
THROUGH THE AFTERNOON WEARS ON AS EVIDENCED BY THE 900MB RELATIVE
HUMIDITY FIELD. THIS MEANS THAT FAR EASTERN COUNTIES ALONG THE HWY
81 WOULD BE LAST TO SEE ANY CLEARING. AFTER BUSTING HIGH TEMPS BY
10+ DEGREES YESTERDAY DUE TO WIDESPREAD LOW STRATUS...AM IN NO
HURRY TO GO WITH THE WARM END OF AVAILABLE GUIDANCE/MODEL
SOLUTIONS TODAY ESPECIALLY IN EASTERN ZONES. AFTER TRYING VARIOUS
SOLUTIONS ON FOR SIZE...ENDED UP GOING WITH THE 00Z NAM ALMOST
EXACTLY...AS ITS TEMP FIELD SEEMED TO BEST-CAPTURE THE GRADUAL
WEST-EAST CLEARING. THIS RESULTS IN A DECENT RANGE FROM NEAR 80
FAR WEST ...LOW-MID 70S CENTRAL AND UPPER 60S EAST. PLEASE NOTE
THESE VALUES ARE AT LEAST A FEW DEGREES COOLER THAN PREVIOUS
FORECAST ALL AREAS...AND AS MUCH AS 5-8 DEGREES COOLER IN THE
EAST. LIKE YESTERDAY...COULD EASILY FORESEE HIGHS BEING OFF BY 5+
DEGREES DEPENDING ON STRATUS/FOG TRENDS.
TONIGHT...KEPT OUT ALL MENTION OF PRECIP CWA-WIDE...AND AM NOT
EXPECTING A DENSE FOG REPEAT SUCH AS THE ONGOING ONE...BUT DID
INSERT A PATCHY FOG MENTION INTO SEVERAL COUNTIES NORTH OF I-80
AFTER MIDNIGHT IN CLOSEST PROXIMITY TO THE HIGHEST BOUNDARY LAYER
RELATIVE HUMIDITY POOLING IN THE VICINITY OF THE LEADING EDGES OF
THE INVADING COLD FRONT. CLOUD TRENDS TONIGHT ARE CERTAINLY A
CHALLENGE...WITH THE POTENTIAL FOR QUITE AN INCREASE IN STRATUS
TOWARD SUNRISE NEAR THIS BOUNDARY...FOLLOWING WHAT SHOULD BE A
FAIRLY CLEAR EVENING FOR MOST AREAS. ALOFT...THE BIG PICTURE
INVOLVES A LEAD SHORTWAVE TRACKING ACROSS FAR SOUTH CENTRAL
CANADA...WHICH HELPS DRIVE THE SURFACE FRONT INTO THE NORTHERN
CWA...WHILE A TROUGH AXIS SETS UP FROM SOUTHWEST-NORTHEAST ACROSS
KS. KEPT LOWS SIMILAR TO PREVIOUS FORECAST AND A GUIDANCE
BLEND...RANGING FROM LOW-MID 40S NORTHWEST TO UPPER 50S/NEAR 60
SOUTHEAST WHERE DEWPOINTS WILL BE ON THE INCREASE.
WEDNESDAY...OTHER THAN THE LINGERING PATCHY FOG MENTION NORTH IN
THE MORNING...HAVE KEPT OUT ANY OTHER WEATHER MENTION THROUGH
SUNSET...AS THE GENERAL MODEL CONSENSUS IS TO KEEP ANY LIGHT
DAYTIME DRIZZLY PRECIP NORTHEAST OF THE CWA...AND ANY LATE-DAY
CONVECTION ALONG/NEAR THE INVADING COLD FRONT JUST SOUTHEAST OF
THE CWA. THAT BEING SAID...SKY COVER AND TEMP TRENDS ARE AGAIN
QUITE A CHALLENGE...AS QUITE A BIT OF STRATUS SHOULD DOMINATE MUCH
OF THE NORTHWEST CWA WITH MORE SUNSHINE SOUTHEAST.
FORTUNATELY...THE LATEST MODEL RUNS ARE IN REASONABLY GOOD
AGREEMENT REGARDING WHAT WILL CERTAINLY BE A SHARP TEMP
GRADIENT...AND ONLY MADE MINOR ADJUSTMENTS TO PREVIOUS
FORECAST...AIMING FOR A RANGE FROM UPPER 50S FAR NORTH...MID 60S
TO LOW 70S TRI CITIES AREA...AND LOW 80S FAR SOUTHEAST IN THE
HEBRON-BELOIT CORRIDOR. AGAIN THOUGH...5+ DEGREE DEVIATIONS FROM
CURRENT FORECAST ARE VERY POSSIBLE IF NOT LIKELY. PONDERED GOING
WITH A NON-DIURNAL TEMP TREND BEHIND THE FRONT...BUT MODELS ARE
NOT REALLY SHOWING MUCH OF AN AFTERNOON DROP SO STUCK WITH
TRADITIONAL MID-LATE AFTERNOON HIGHS ALL AREAS FOR NOW. THIS COLD
FRONT WILL NOT EXACTLY BLAST THROUGH THE AREA...AND BY SUNSET WILL
JUST BE REACHING FAR SOUTHEAST ZONES...WHILE MOST OF THE CWA WILL
ALREADY BE IN SUSTAINED NORTH WINDS 15-20 MPH.
WEDNESDAY NIGHT IS CLEARLY STILL THE MAIN 12-HOUR WINDOW FOR
POTENTIALLY DECENT RAIN AMOUNTS...AND ACTUALLY RAISED POPS INTO
THE 60-70 PERCENT RANGE ACROSS MUCH OF THE EASTERN CWA...WHILE
LEAVING SOUTHWEST AREAS IN THE 40-50 PERCENT RANGE. IN
SHORT...LARGE SCALE FORCING/MID LEVEL FRONTOGENESIS RAMPS UP AS A
POTENT OPEN WAVE OVER THE CENTRAL ROCKIES MOVES INTO THE CENTRAL
PLAINS...FEATURING A 110+KT 300MB JET STREAK. LEFT THE POP/WEATHER
GRIDS AS ONE 12-HOUR BLOCK FOR NOW...BUT GENERAL THINKING IS THAT
MOST WIDESPREAD COVERAGE OF SHOWERS/STORMS WILL HOLD OFF UNTIL
NEAR/AFTER MIDNIGHT...UNLESS SOME EVENING ACTIVITY FLARES UP IN
THE FAR SOUTH/SOUTHEAST NEAR THE MAIN SURFACE FRONT. LATEST NAM
CONTINUES TO SHOW A HEALTHY CORRIDOR OF MUCAPE 1500+ J/KG IN THE
850-700MB LAYER MAINLY ACROSS THE SOUTHEAST 1/2 OF THE
CWA...DROPPING OFF SHORTLY TO THE NORTHWEST. HOWEVER...WILL KEEP
ISOLATED THUNDER EVEN IN THIS NORTHWEST AREAS. WITH VERY STRONG
DEEP-LAYER SHEAR OF 60+ KNOTS MOVING IN...HAVE INCREASING CONCERNS
THAT AT LEAST MARGINALLY SEVERE HAIL COULD OCCUR IN SOUTHEAST
COUNTIES...AND DESPITE SPC KEEPING THE OFFICIAL DAY2 SLIGHT RISK
OUTLOOK JUST EAST OF THE CWA...AT LEAST FOR NOW...WILL GO AHEAD
AND ADD THIS MENTION TO THE HAZARDOUS WEATHER OUTLOOK AS THESE
STRONG DYNAMICS ARE HARD TO IGNORE. DEPENDING ON HOW WIDESPREAD
STORMS ARE...COULD FORESEE SOME FORTUNATE AREAS RECEIVING IN
EXCESS OF ONE-HALF INCH OF RAIN BUT THIS WILL PROBABLY BE THE
EXCEPTION. ALTHOUGH SOME SNOW OR RAIN/SNOW MIX COULD TRY
DEVELOPING IN WESTERN NEBRASKA IN THE COLDER AIR WELL BEHIND THE
FRONT...LATEST CONSENSUS IS THAT WINTRY PRECIP WED NIGHT SHOULD
FOCUS AT LEAST 50 MILES WEST OF THE CWA...AND THUS WILL KEEP ANY
SNOW MENTION OUT FOR NOW.
THURSDAY...SPLIT THE DAY INTO 6-HOUR BLOCKS...WITH ALL PRECIP GONE
BY THE AFTERNOON HOURS...AND POTENTIALLY EVEN GONE BY MID-MORNING
IN MOST AREAS PER SOME OF THE LATEST TRENDS INCLUDING THE 00Z
ECMWF...WHICH QUICKLY SHUTS OFF THE MID LEVEL LIFT/SATURATION FROM
NORTHWEST-SOUTHEAST. LATER ADJUSTMENTS WILL BE NEEDED...BUT FOR NOW
KEPT 20-40 POPS ACROSS MOST OF THE CWA IN THE MORNING FOR GENERAL
LIGHT RAIN...WITH NO THUNDER MENTION AND STILL NO SNOW
MENTION...ALTHOUGH SUPPOSE A FEW FLURRIES COULD SNEAK INTO FAR
NORTHWEST ZONES JUST BEFORE PRECIP SHUTS OFF FOR GOOD GIVEN
SURFACE TEMPS FORECAST TO DROP INTO THE MID 30S EARLY THURSDAY
MORNING. OTHERWISE...EXPECT INCREASING SUNSHINE AS THE DAY WEARS
ON...ALTHOUGH IT WILL REMAIN QUITE BREEZY WITH SUSTAINED NORTH
WINDS AROUND 20 MPH WITH GUSTS TO AROUND 30 MPH. FOR HIGH
TEMPS...RAW NAM VALUES ARE WELL INTO THE MID 50S ALL AREAS...BUT
WAS NOT WILLING TO GO QUITE THIS WARM YET...AND THUS ONLY MADE
MINOR ADJUSTMENTS TO PREVIOUS FORECAST WITH MOST NEB ZONES TOPPING
OUT UPPER 40S AND KS LOWER 50S.
THURS NIGHT...THIS LOOKS TO BE THE MOST UNEVENTFUL PERIOD OF THE
NEXT 72 HOURS...AS AN EXPANSIVE SURFACE RIDGE AXIS SETTLES INTO
THE REGION FROM THE NORTH...AND ANY LIGHT SNOW ACCUMULATIONS
ASSOCIATED WITH TRAILING MID LEVEL SHORTWAVE ENERGY AND LOW LEVEL
UPSLOPE FLOW SHOULD REMAIN NO CLOSER THAN THE NEB/CO/KS BORDER
AREA. DESPITE A POTENTIAL INCREASE IN MID LEVEL CLOUDS...OPTED TO
LOWER LOW TEMPS 2-3 DEGREES FROM PREVIOUS FCST AND POSSIBLY NOT
ENOUGH...BUT AT LEAST GETTING ALL AREAS INTO THE SUB-FREEZING
26-32 RANGE.
.LONG TERM...STARTING 12Z FRIDAY...THE LONGWAVE TROUGH ACROSS THE
WEST COAST THIS MORNING WILL BE CENTERED OVER THE PLAINS ON
FRIDAY...WITH SEVERAL EMBEDDED WEAK DISTURBANCES EXPECTED TO HAVE
LITTLE IMPACT IN THE WAY OF CHANCES FOR PRECIP ACROSS THE LOCAL
AREA. SOME DISCREPANCIES EVIDENT WITH THE HANDLING OF THIS TROUGH
AS IT PUSHES EAST LATE IN THE WEEKEND...WITH THE EC QUICKLY BUILDING
A RIDGE OVER THE INTERMOUNTAIN WEST RESULTING IN RISING HEIGHTS
ACROSS THE PLAINS...IN RESPONSE TO THE LONGWAVE TROUGH INTERACTS
WITH A TROPICAL DISTURBANCE OFF THE EASTERN SEABOARD...AND THE
LATEST GFS DEPICTING A MORE ZONAL WEST TO NORTHWEST FLOW ACROSS THE
REGION BY EARLY NEXT WEEK...AS THE AFOREMENTIONED TROPICAL
DISTURBANCE INSTEAD TRACKS OUT INTO THE OPEN ATLANTIC. EITHER
WAY...THIS APPEARS TO BE A DRY PATTERN FOR THE LOCAL AREA AS THERE
ARE NO SIGNIFICANT FEATURES FORECAST TO IMPACT THE AREA IN THE
DIVERGENT UPPER LEVEL FLOW PATTERNS DEPICTED AMONGST THE LONG TERM
MODELS. THEREFORE...EXPECT DRY CONDITIONS...WITH CONTINUED
UNSEASONABLY COOL TEMPERATURES...TO AT LEAST START THE EXTENDED
PERIODS...WITH TEMPERATURES POSSIBLY WARMING CLOSER TO
CLIMATOLOGY...WHILE REMAINING DRY...EARLY NEXT WEEK IF THE EC
SOLUTION ENDS UP BEING CORRECT. HOWEVER...DUE TO THE UNCERTAINTY OF
THE SYNOPTIC SCALE PATTERN EARLY NEXT WEEK...STUCK WITH ALLBLEND
MODEL SOLUTION THIS MORNING...WITH NO NOTABLE TWEAKS TO SPEAK OF.
&&
.PREV DISCUSSION... /ISSUED 1243 AM CDT TUE OCT 23 2012/
AVIATION...06Z TAF. STRATUS CONTINUES TO ENCOMPASS A GOOD
PORTION OF THE CENTRAL PLAINS AND CIGS ARE EXPECTED TO REMAIN LIFR
THROUGH THE EARLY MORNING HOURS TUESDAY. IN PRESENCE OF LLVL
MOISTURE AND MIXING ABOVE THE MOISTURE/CLOUD DECK...LOOK FOR
INTERMITTENT DRIZZLE FOR AT LEAST THE FIRST PART OF THE NIGHT WITH
VSBYS IN THE LIFR CATEGORY IN AREAS OF FG/BR. THE LIFR/IFR
CONDITIONS WILL PERSIST INTO THE FIRST HALF OF THE DAY
TUESDAY...WITH IMPROVEMENT BY MIDDAY...AS CLOUDS BEGIN TO
SCATTER AND DRY AIR BEGINS TO ADVECT IN ACROSS THE REGION. WINDS
OVERNIGHT WILL CONTINUE TO BE LIGHT AND VARIABLE...EVENTUALLY
REACHING ABOUT 10 KTS OUT OF THE SOUTH TUESDAY AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ039>041-
046>049-060>064-072>077-082>087.
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ005>007-
017>019.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
410 AM CDT TUE OCT 23 2012
.DISCUSSION...
PRIMARY FOCUS THROUGH THIS FORECAST PERIOD IS FOG AND TEMPERATURES
TODAY...THEN RAIN/SNOW CHANCES FOCUSED ON WEDNESDAY NIGHT AND
THURSDAY. BEYOND THAT...COLDER TEMPERATURES FOR THE LATTER HALF OF
THE WEEK.
WATER VAPOR IMAGERY THIS MORNING SHOWS A LONGWAVE TROUGH OVER THE
EASTERN PACIFIC INTO THE WESTERN CONUS...WITH RIDGING ACROSS THE
GREAT LAKES. A WEAK SHORTWAVE TROUGH WAS OBSERVED ACROSS THE
NORTHERN PLAINS...WITH SUBSIDENCE ALOFT ACROSS NEBRASKA HELPING TO
KEEP THE MID-LEVELS DRY THIS MORNING. SEVERAL OTHER SHORTWAVES OF
NOTE WITHIN THE LONGWAVE TROUGH WERE ONE OVER NEVADA...WITH
ANOTHER STILL OVER THE OCEAN. AT THE SURFACE...SOUTH TO SOUTHEAST
FLOW WAS BRINGING IN LOW LEVEL MOISTURE AND WITH THE DRY AIR
ALOFT...FOG HAS DEVELOPED ACROSS ALMOST ALL OF NEBRASKA BY 08Z.
THIS HAS KEPT TEMPERATURES UP...WITH READINGS IN THE MID 40S TO
LOW 50S. THE OTHER FEATURE TO NOTE IS LOW PRESSURE ON THE LEE SIDE
OF THE ROCKIES.
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ACCORDING TO THE RUC AND THE NAM...FOG SHOULD SLOWLY DISSIPATE
FROM THE WEST...BUT PLACES OVER THE EASTERN PART OF THE FORECAST
AREA...EAST OF HIGHWAY 83 COULD SEE THE FOG LINGER INTO THE EARLY
AFTERNOON HOURS. THE FOG WILL HAVE A BIG IMPACT ON HIGH
TEMPERATURES TODAY SO IF IT FAILS TO DISSIPATE BY 18Z OR
19Z...TEMPERATURES COULD BE UP TO 10 DEGREES TO WARM IN PLACES.
DAY SHIFT WILL NEED TO MONITOR TRENDS IN CASE TEMPERATURE FORECAST
NEEDS TO BE MODIFIED. 850MB TEMPERATURES WILL INCREASE TODAY
/BETWEEN 15C AND 23C/ DUE TO WARM AIR ADVECTION AHEAD OF THE AREA
OF LOW PRESSURE TO THE WEST. ASSUMING SKIES CLEAR...TEMPERATURES
SHOULD WARM CONSIDERABLY...WITH LOW 80S POSSIBLE ACROSS SOUTHWEST
NEBRASKA. THE SHORTWAVE TROUGH OVER NEVADA WILL LIFT INTO MONTANA
TODAY...WHICH WILL GIVE THE FRONT TO THE WEST A BIT OF A PUSH
EASTWARD. THE NAM PUSHES A DRYLINE ACROSS THE SANDHILLS THIS
AFTERNOON...WHICH COULD DROP DEWPOINTS INTO THE LOW 30S. GOING
SOUTH...DEWPOINTS WILL DROP INTO THE 30S AS WELL AS THE DRYLINE
PROGRESSES EAST. THIS WILL PROMOTE DEEP MIXING TO NEAR 700MB.
WINDS THROUGH THE MIXED LAYER WILL BE STRONGEST ACROSS NORTHWEST
NEBRASKA...WHERE GUSTS TO 30 MPH LOOK POSSIBLE THIS AFTERNOON.
GOING SOUTH...WINDS ALOFT DECREASE SO WINDY CONDITIONS ARE NOT
EXPECTED. WITH THE TEMPERATURES EXPECTED TODAY...LOWEST RELATIVE
HUMIDITY WILL BE ACROSS SOUTHWEST NEBRASKA...WITH VALUES DROPPING
TO THE MID 20S WHERE WINDS WILL BE STRONG. AS IS
FORECAST...CRITICAL FIRE WEATHER CONDITIONS WILL NOT BE
MET...ALTHOUGH MARGINAL CONDITIONS WILL BE LIKELY IN A FEW
LOCATIONS FOR AT LEAST A FEW HOURS TODAY. AGAIN...CLOUD COVER
COULD HAMPER THIS FROM OCCURRING...SO WILL NEED TO MONITOR TRENDS
FOR POTENTIAL FIRE WEATHER ISSUES TODAY.
THE MONTANA WAVE LIFTS INTO CANADA TONIGHT...WITH A COLD FRONT TO
THE WEST PROGRESSING SOUTHEAST ACROSS NEBRASKA TONIGHT. BY MID
MORNING WEDNESDAY SHOULD BE THROUGH MOST OF THE FORECAST AREA.
COULD AGAIN SEE SOME FOG WEDNESDAY MORNING...BUT THIS SHOULD BE
CONFINED TO AREAS RIGHT ALONG AND BEHIND THE FRONT WHERE LOW LEVEL
MOISTURE POOLS. A THE SHORTWAVE TROUGH WILL ALSO MOVE ONLAND
TONIGHT...WHICH WILL THEN PROGRESS ACROSS UTAH AND INTO COLORADO
ON WEDNESDAY. AS THIS IS ONGOING...A 700MB TROUGH WILL PASS ACROSS
THE NORTHERN AND CENTRAL PLAINS WEDNESDAY AND WEDNESDAY NIGHT.
MODELS ARE SHOWING GOOD FRONTOGENETICAL FORCING...WHILE THE
LOCATION OF THE UPPER LEVEL JET STREAK PUTS NORTHWEST NEBRASKA IN
AN AREA OF GOOD LARGE-SCALE LIFT. THE SIGNAL HAS BEEN QUITE
CONSISTENT IN TIMING AND LOCATION OF THE BEST FORCING FROM THE
DIFFERENT MODELS OVER THE PAST FEW DAYS SO CONFIDENCE HAS
INCREASED IN GETTING PRECIPITATION ACROSS THE FORECAST AREA. IT
MAY TAKE A BIT OF TIME TO SATURATE THE LOW LEVELS...SO ONLY BEGAN
CHANCES FOR RAIN IN THE FAR NORTHERN PARTS OF SHERIDAN AND CHERRY
COUNTIES WEDNESDAY MORNING AND SLOWLY EXPANDING SOUTH THROUGH THE
AFTERNOON. WEDNESDAY EVENING LOOKS TO SEE THE BEST CHANCES FOR
PRECIPITATION IN AREAS NORTHWEST OF AN IMPERIAL TO VALENTINE
LINE...AND THOUGH DO HAVE RAIN CHANCES TO THE EAST...LOWERED
CHANCES BEFORE MIDNIGHT AS TOO MUCH DRY AIR LOOKS TO EXIST IN
THESE AREAS. THE PRECIPITATION AREA DOES SHIFT TO THE SOUTH AND
EAST AFTER MIDNIGHT...BUT AS THE PRIMARY SHORTWAVE TROUGH EXITS
THE AREA BY 12Z THURSDAY MORNING...LARGE-SCALE FORCING WILL
DETERIORATE SO CHANCES HAVE LOWERED FOR THURSDAY. BY LATE
AFTERNOON THURSDAY...EXPECT THE FORECAST AREA TO SEE PRIMARILY DRY
CONDITIONS. THERE IS ANOTHER SHORTWAVE THAT WILL ROUND THE
LONGWAVE TROUGH LATER THURSDAY AND THURSDAY NIGHT...BUT THE TREND
CONTINUES TO GO SOUTH SO PRECIPITATION CHANCES LOOK TO STAY TO THE
SOUTH. TEMPERATURE PROFILES CONTINUE TO SHOW THE PRECIPITATION
TYPE BEGIN AS RAIN...BUT CHANGE OVER TO A RAIN/SNOW MIX WITH SNOW
BECOMING THE DOMINANT TYPE ACROSS THE NORTHWEST AREAS AFTER
MIDNIGHT WEDNESDAY NIGHT. HAVE RAIN OR SNOW IN THE FORECAST ACROSS
THE ENTIRE AREA FOR THURSDAY MORNING AS THE PROFILES HUG 0C IN THE
LOWEST LEVELS ABOVE THE SURFACE. DON/T EXPECT MUCH ACCUMULATION OF
SNOW...WITH PRECIPITATION ACCUMULATIONS UP TO A THIRD OF AN INCH
MAINLY NORTH OF INTERSTATE 80.
.LONG TERM...FRIDAY THROUGH MONDAY
COLD TEMPERATURES WILL BE THE HIGHLIGHT FOR THE WEEKEND AS HIGHS
WILL BE HARD PRESSED TO MAKE IT OUT OF THE 30S AND 40S FOR FRIDAY
AND SATURDAY. LOWS ALSO WILL BE QUITE COLD...ALTHOUGH THE 23.00Z
MODEL SOLUTIONS ARE A BIT WARMER FOR BOTH FRIDAY AND SATURDAY
NIGHTS WITH THE SURFACE HIGH NOW LOOKING TO STAY OFF TO THE EAST
OF THE FORECAST AREA. LOWS SHOULD STILL EASILY DROP INTO THE
20S...WITH TEENS POSSIBLE FRIDAY NIGHT.
THE TREND NOW LOOKS FOR WARMER CONDITIONS GOING INTO NEXT WEEK AS
RIDGING BUILDS OVER THE WESTERN HALF OF THE COUNTRY. THIS WILL
BRING MILD TEMPERATURES BACK INTO THE CENTRAL PLAINS WITH 850MB
TEMPERATURES WARMING INTO THE TEENS AGAIN BY MONDAY...COMPARED TO
READINGS BELOW 0C WHICH WILL BE EXPERIENCED FRIDAY AND SATURDAY.
THE FORECAST IS DRY THROUGH THIS PERIOD AS THE LONGWAVE TROUGH
WILL PUSH THE MOISTURE ACROSS THE PLAINS WELL TO THE
SOUTHEAST.
&&
.AVIATION...
LIFR/IFR CIGS AND VSBY IMPROVE TO VFR FROM WEST TO EAST BETWEEN 15Z
AND 18Z ALONG AND WEST OF HIGHWAY 83. EAST OF HIGHWAY 83...LIFR/IFR
CIGS AND VIS IMPROVE TO IFR/MVFR CIGS AROUND 18Z AND THEN VFR BY 21Z.
A COLD FRONT WILL DROP INTO THE FCST AREA TONIGHT WITH MVFR/IFR CIGS
POSSIBLE AFTER 06Z TUESDAY NIGHT.
&&
.FIRE WEATHER...
POTENTIAL RED FLAG CONDITIONS WILL BE MONITORED ACROSS WRN NEB THIS
AFTERNOON DEPENDING ON THE PROGRESS OF A CLEARING LINE FCST TO
DEVELOP ACROSS THE PANHANDLE THIS MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...BROOKS
AVIATION/FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
318 AM CDT TUE OCT 23 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY...
LATEST WATER VAPOR IMAGERY SHOWS A LONG FETCH OF MOIST SOUTHWEST
FLOW WITH SEVERAL DISTURBANCES EJECTING OUT FROM AN UPPER LOW/LONG
WAVE TROUGH ANCHORED ALONG THE WEST COAST. THE NEXT PLUME OF
MOISTURE IS NOW EXPANDING OVER SOUTHEAST MONTANA AND THIS WILL
CONTINUE MOVING NORTHEAST THROUGH THE DAY. LATEST REGIONAL RADAR
SHOWS PERSISTENT RAIN IN THE NORTH CENTRAL UP TO THE NORTHERN
BORDER WITH SNOW IN THE FAR NORTHWEST. FURTHER SOUTH THE PRECIPITATION
WAS MORE RAGGED AND SCATTERED. A SURFACE LOW PRESSURE WILL MOVE
FROM NORTHEAST WYOMING ACROSS NORTHERN SOUTH DAKOTA TODAY WITH AN
INVERTED TROUGH REACHING INTO CENTRAL NORTH DAKOTA THIS AFTERNOON.
THE NAM/GFS ARE IN GOOD AGREEMENT WITH FRONTOGENESIS INITIATING IN
THE H85-H7 LAYER FROM AROUND GARRISON TO RUGBY AND INTO BOTTINEAU
TODAY. THIS AREA COINCIDES NICELY WITH A MAXIMUM IN THE OMEGA/LIFT
SIGNATURE PER GFS...BUT A LITTLE LESS ROBUST IN THE NAM. HOWEVER
BOTH MODELS ALONG WITH THE LATEST HRRR AGREE THAT THIS WILL BE THE
TARGET FOR HIGHEST POPS AND QPF. THUS WILL TAILOR THE NORTH
CENTRAL WITH NUMEROUS SHOWERS AND THEN TAPER THE WORDING FURTHER
SOUTH FROM SCATTERED TO ISOLATED. SOUTH CENTRAL NORTH DAKOTA WILL
BE IN THE WARM SECTOR PORTION OF THE LOW TODAY WITH HIGHS REACHING
THE MID 50S...AND MID 60S IN THE FAR SOUTHEAST. IT WILL REMAIN
COOL IN THE NORTH AND WEST WITH HIGHS IN THE MID TO UPPER 40S.
FOR TONIGHT INTO WEDNESDAY...WITH THE AFOREMENTIONED SURFACE LOW
EXITING THE AREA THIS EVENING...OUR ATTENTION TURNS TO THE NEXT
JET STREAK EJECTING INTO NORTH DAKOTA AFTER 06Z WEDNESDAY. THE
NAM/GFS BOTH SHOW FRONTOGENESIS IN THE ANOTHER H85-H65 LAYER
BEING INITIATED IN THE FAR SOUTH AND SOUTHEAST AFTER 06Z. THIS
BECOMES THE FOCUS FOR MORE PRECIPITATION AFTER 06Z WEDNESDAY AND
CONTINUING THROUGH THE DAY WEDNESDAY...WITH LIKELY POPS IN THE FAR
SOUTHEAST AND ISOLATED TO SCATTERED IN THE SOUTH. THE ONLY THREAT FOR
SNOW APPEARS DURING THE EARLY MORNING IN THE FAR SOUTHWEST WHERE
ISOLATED SNOW SHOWERS MAY DEVELOP WITH COLDER AIR ALREADY IN PLACE.
SOUNDINGS SUPPORT RAIN ELSEWHERE...ESPECIALLY WHERE THE POPS ARE
IN THE LIKELY CATEGORY IN THE FAR SOUTHEAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY.
MODELS IN GOOD AGREEMENT WITH BROAD TROUGH OVER CENTRAL NORTH
AMERICA THROUGH MOST OF THE PERIOD. CLOSED UPPER LOW CENTER MOVES
TO HUDSON BAY BY 00Z SATURDAY WITH NORTHWEST FLOW SETTING UP OVER
NORTHERN PLAINS AS MAIN TROUGH AXIS SHIFTS EAST. MAIN IMPACT ON
OUR AREA WILL BE BELOW NORMAL TEMPERATURES WITH HIGHS GENERALLY IN
THE 30S TO NEAR 40 ALONG SD BORDER AND LOWS IN THE 20S. OTHER THEN
A LOW CHANCE OF PRECIP WEDNESDAY NIGHT ACROSS THE SOUTH AS UPPER
WAVE ROTATES ACROSS THE REGION...MOSTLY DRY CONDITIONS ARE
EXPECTED UNTIL MONDAY WHEN A SYSTEM APPROACHES.
&&
.AVIATION...AS OF 08Z TAF LOCATIONS GENERALLY IN IFR TO LIFR
CATEGORY DUE TO LOW CEILINGS WITH EXCEPTION OF KJMS WHICH WAS STILL
MVFR. EXPECT SHOWERS CONTINUING INTO THE AFTERNOON...ENDING FROM
SOUTHWEST TO NORTHEAST. EXACT TIMING OF TRANSITION TO MVFR AND VFR
APPEARS TO BE AROUND 18Z FOR KDIK AND AFTER 21Z FOR
KISN...KMOT...KBIS AND KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
LONG TERM/AVIATION....JNS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
720 AM EDT TUE OCT 23 2012
.SYNOPSIS...
A FRONT WILL LINGER ACROSS LAKE ERIE THROUGH MID WEEK. NEXT COLD
FRONT WILL PUSH THROUGH LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TWEAKED THE TIMING OF THE SHOWERS THIS MORNING.
ORIGINAL DISCUSSION...
FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL AND LOWER GREAT LAKES. TWO
SEPARATE WAVES WILL MOVE ALONG THE BOUNDARY TODAY. THE FIRST WAVE
IS WITH THE CONVECTION THIS MORNING. EXPECT A BREAK BY LATE
MORNING THEN A SECOND WAVE LATER THIS AFTERNOON. WHERE WILL THE
SHOWERS SET UP. STILL DOUBTS IN MY MIND...BEST CHANCES WOULD BE
THE LAKESHORE COUNTIES WITH DECREASING CHANCES THE FURTHER SOUTH
YOU GO. EXPECT TEMPS TO REMAIN WELL ABOVE NORMAL WITH TEMPS IN THE
LOWER TO MID 70S. IF GET SOME CLOUD BREAKS EARLY THIS AFTERNOON
BEFORE SECOND WAVE COULD EVEN BE A LITTLE WARMER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
SECOND WAVE WILL EXIT AREA OVERNIGHT WITH A CHANCE OF A FEW
LINGERING SHOWERS INTO WEDNESDAY MORNING. UPPER RIDGE BUILDS
QUICKLY OVER THE AREA WEDNESDAY AND REMAINS IN PLACE TO THE END OF
THE WORK WEEK. AS A RESULT MUCH ABOVE NORMAL TEMPERATURES WILL
CONTINUE THROUGH THURSDAY. BUT ALL GOOD THINGS COME TO AN END. THE ECMWF
IS COMING MORE IN LINE WITH THE GFS TIMING OF THE NEXT SYSTEM.
MODELS PUSH FRONT INTO NW OH FRIDAY AND ACROSS MOST OF AREA FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THIS PERIOD IS BECOMING A LITTLE MORE CLEAR BUT IT STILL HAS SOME
DIFFERENCES. THE FRONT IS EAST OF THE AREA BY SATURDAY MORNING WITH
COLD AIR FLOWING IN FROM MICHIGAN. BY SATURDAY EVENING THE LAKE AND
850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 14C. THE THREAT OF
SHOWERS WILL BE DECREASING FROM WEST TO EAST SATURDAY. HIGH PRESSURE
WILL BE BUILDING IN SLOWLY FROM THE NORTHWEST SATURDAY INTO SUNDAY
AND THAT WILL DECREASE ANY LAKE ENHANCED SHOWERS THAT TRY TO MOVE
INTO NORTHWEST OHIO FROM LAKE MICHIGAN. HOWEVER...LAKE EFFECT
SHOWERS WILL CONTINUE OVER THE EASTERN COUNTIES. ON MONDAY THE 00Z
ECMWF HAS A MORE PRONOUNCED TROF OVER THE EASTERN LAKES. IF THIS
OCCURS IT MAY
KEEP THE THREAT OF PRECIPITATION GOING LONGER AND IT WILL BRING IN A
LITTLE COLDER AIR...SO WE WILL HAVE TO CONTINUE TO MONITOR THE
PRECIPITATION TYPE. AT THIS TIME STILL JUST FORECASTING RAIN. DIDN`T
MAKE MUCH IN THE WAY OF CHANGES TO THE EXTENDED FOR
TEMPERATURES...THEY WILL BE BELOW NORMAL.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
ONE SHORT WAVE WAS MOVING THROUGH THE AREA THIS MORNING AND
CAUSING SOME SHOWERS. ANOTHER SHORT WAVE WILL MOVE THROUGH FOR
THE AFTERNOON. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THIS ARE
OVER CENTRAL IL AND WEST CENTRAL INDIANA. THEY SEEM TO BE MOVING
FASTER THAN ONE WOULD THINK BASED ON THE LOCATION OF THE SHORT
WAVE. THE HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON THIS SO WENT
WITH THAT TIMING. CONFIDENCE IS MODERATE ON HOW IT WILL ALL PLAY
OUT WITH THE BEST CHANCES OVER NORTHWEST OHIO AND ALONG THE
LAKESHORE. A STATIONARY FRONT JUST TO THE NORTH OF LAKE ERIE WILL
HELP FOCUS THE PRECIPITATION. CONDITIONS WILL BE MAINLY VFR
EXCEPT BRIEFLY MVFR OR LESS IN THE HEAVIER SHOWERS AND
THUNDERSTORMS. HOWEVER...SOME MVFR CEILINGS COULD DEVELOP IN THE
HIGH MOISTURE NEAR LAKE ERIE. CONFIDENCE IS LOW.
.OUTLOOK...NON VFR POSSIBLE IN SHOWERS AT TIMES FRIDAY EVENING
THROUGH SATURDAY.
&&
.MARINE...
A BOUNDARY MAY TRY TO DRIFT INTO THE EASTERN PORTION OF LAKE ERIE
LATER TODAY INTO WEDNESDAY. OTHER THAN THAT MAINLY A SOUTH TO
SOUTHWEST FLOW THROUGH FRIDAY. CONDITIONS SHOULD NOT MEET SMALL
CRAFT ADVISORY CRITERIA. THE ONLY THREAT ON THE LAKE THROUGH
WEDNESDAY WILL BE A NEED FOR A SPECIAL MARINE WARNING BECAUSE OF
THUNDERSTORMS AND THAT IS A SMALL CHANCE.
A COLD FRONT WILL MOVE THROUGH FRIDAY INTO FRIDAY NIGHT AND
NORTHERLY WINDS BEHIND IT MAY PROMPT A NEED FOR A SMALL CRAFT
ADVISORY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DJB
NEAR TERM...DJB
SHORT TERM...DJB
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1254 PM CDT TUE OCT 23 2012
.DISCUSSION.../ISSUED AT 920 AM CDT/
DENSE FOG PERSISTING ACROSS NORTHEAST QUARTER OF THE FORECAST AREA
LONGER THAN EARLIER ANTICIPATED. FOR NOW...HAVE EXTENDED DENSE FOG
ADVISORY FOR SOUTHWEST MINNESOTA AND I-29 CORRIDOR FROM SIOUX FALLS
NORTHWARD UNTIL 10 AM...THOUGH HRRR SUGGESTS LOW VISIBILITY MAY LAST
EVEN LONGER THAN THAT...ESPECIALLY ALONG AND WEST/UPSLOPE OF BUFFALO
RIDGE. WILL CONTINUE TO EVALUATE THAT OVER THE NEXT HOUR AND ADJUST
AGAIN IF NECESSARY PRIOR TO 15Z. FOG/STRATUS WILL HOLD TEMPERATURES
DOWN ACCORDINGLY...AND HAVE BEGUN TO TREND AFTERNOON READINGS LOWER
ACROSS THE NORTHEAST CWA...THOUGH AGAIN...FURTHER ADJUSTMENTS MAY BE
NECESSARY IF FOG PERSISTS LATER INTO THE MORNING. LEFT HIGHS IN THE
70S ALONE ACROSS THE SOUTHWEST CWA...AS MODELS STILL SHOW BOUNDARY
AND ASSOCIATED SHIFT TO SOUTHWEST LOW LEVEL FLOW PUSHING INTO THAT
AREA DURING THE AFTERNOON. THIS SHOULD ALLOW DECENT DRYING/MIXING IN
AREAS WEST OF THE JAMES VALLEY.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
TOUGHEST CALL FOR THE 18Z TAF ISSUANCE IS SHORT TERM DISSIPATION OF
THE WIDESPREAD IFR/MVFR STRATUS FIELD. STRONG INVERSION ON KOAX AND
KABR MORNING RAOBS DO NOT LEND CONFIDENCE TO THE ABILITY TO MIX OUT
THE LOWER CEILINGS THIS AFTERNOON...AND LIKELY WILL DEPEND GREATLY
ON ADVECTION/MIXING ON EDGE TO RESULT IN CLEARING...WHICH IS DELAYED
ON CURRENT SET BY SEVERAL HOURS OVER PREVIOUS FORECAST FOR KSUX/KFSD.
IN FACT...CEILINGS MAY RETURN LOWER FOR A COUPLE HOURS EARLY THIS
AFTERNOON AROUND KFSD WITH ADVECTION FROM SOUTH...BACK INTO IFR
LEVELS. FRONTAL ZONE OUT ACROSS WESTERN SOUTH DAKOTA WILL PROGRESS
EASTWARD WILL HAVE BEST DRYING SURGE JUST AHEAD...IMPACTING KHON BY
MID AFTERNOON. FOLLOWING FRONTAL PASSAGE...LIKELY THAT SOME AREAS OF
MVFR OR IFR CEILINGS WILL SPREAD BACK SOUTHWARD INTO KHON...AND ALSO
DEVELOP FARTHER SOUTHEAST TOWARD KFSD/KSUX ALONG WITH INCREASED
MOISTURE LEVELS. FOR NOW...HAVE NOT MENTIONED ANY PRECIPITATION...
BUT POTENTIAL FOR SOME LIGHT DRIZZLE ONCE AGAIN TOMORROW MORNING FOR
KFSD/KSUX AREAS. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 420 AM CDT/
BROAD SWATH OF STRATUS BLANKETING MUCH OF THE NORTHERN AND CENTRAL
PLAINS REMAINS THE PRIMARY CONCERN FOR TODAY. MODELS HOLD ONTO THE
LOW LEVEL MOISTURE THROUGH MUCH OF THE MORNING RESULTING IN THE
WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE AND FOG WILL LIKELY STICK
AROUND THROUGH MID TO LATE MORNING. SOUTHWESTERLY FLOW WILL BEGIN TO
INCREASE ACROSS THE WEST LATER THIS MORNING WHICH SHOULD BEGIN
MIXING DRIER AIR INTO THE LOW LEVELS WHICH SHOULD SCOUR OUT THE
CLOUDS BY AFTERNOON. THE BIG QUESTION IS HOW QUICKLY THE CLEARING
WILL WORK INTO OUR EASTERN HALF AND WHETHER OUR FAR NORTHEAST WILL
SEE SIGNIFICANT CLEARING BY LATE AFTERNOON. THIS WILL LARGE
IMPLICATIONS ON TEMPERATURE TRENDS...AS HEFTY WARM AIR ADVECTION
WILL EASILY PLACE HIGH TEMPERATURES IN THE MID TO UPPER 70S IN THE
WEST. DID KNOCK BACK HIGHS SLIGHTLY TO THE UPPER 60S IN OUR
NORTHEAST GIVEN THE POTENTIAL TO BE CLOUDY FOR THE BETTER PART OF
THE DAYLIGHT HOURS.
THE MILDER TEMPERATURES WILL BE SHORT LIVED AS A LARGE UPPER LEVEL
LOW TRACKS INTO THE SOUTHERN CANADIAN PRAIRIE PROVINCES BY WEDNESDAY
AND DROPS A COLD FRONT THROUGH THE NORTHERN PLAINS. THE SURFACE
FRONT DIGS THROUGH THE FORECAST AREA TUESDAY AFTERNOON AND TUESDAY
NIGHT THEN STALLS JUST SOUTH OF THE FORECAST AREA WITH LITTLE IMPACT
OUTSIDE OF SOME INCREASED CLOUD COVERAGE. ON WEDNESDAY...SURFACE LOW
PRESSURE DEVELOPS IN EASTERN KANSAS AND PUSHES NORTHEAST INTO
WESTERN IOWA LATE IN THE DAY. THE PRECISE TIMING OF THIS FEATURE AND
THE POTENTIAL LIFTING OF THE WARM FRONT INTO OUR SOUTHEASTERN
COUNTIES ARE STILL A BIT UNCERTAIN. HOWEVER...WITH INCREASED SHEAR
AND NAM MUCAPE APPROACHING 2000 J/KG NEAR THE BOUNDARY...COULD SEE
SOME THUNDERSTORM ACTIVITY IN ADDITION TO SHOWERS. A LARGE DETERRENT
TO ANY SURFACED BASED/SEVERE CONVECTION WILL BE THE STRONG CAPPING
IN PLACE IN THIS AREA. A SECOND AREA TO WATCH FOR POTENTIAL
PRECIPITATION ON WEDNESDAY WILL BE ACROSS THE FAR WESTERN CWA...WITH
STRONG 850 MB FRONTOGENESIS SETTING UP ACROSS CENTRAL AND
NORTHEASTERN SOUTH DAKOTA. WILL KEEP CHANCEY POPS IN PLACE FOR THE
DAY WITH LARGE UNCERTAINTY WITH THE BOUNDARY PLACEMENTS AND
CONDITIONAL CONVECTIVE POTENTIAL.
THE MID LEVEL TROUGH STARTS KICKING EASTWARD WEDNESDAY NIGHT WITH
THE MID LEVEL FRONTOGENESIS SHIFTING INTO OUR CENTRAL CWA BY
DAYBREAK THURSDAY. IT LOOKS LIKE A VERY STRONG POTENTIAL FOR SOME
DECENT RAINFALL WEDNESDAY NIGHT AND EARLY THURSDAY AND HAVE BOOSTED
POPS TO CATEGORICAL FOR THE CENTRAL AND EASTERN CWA. RAINFALL
AMOUNTS OF AROUND A QUARTER TO HALF INCH LOOK REASONABLE AT THIS
POINT. MUCH COOLER TEMPERATURES WILL ARRIVE DURING THIS TIME...WITH
TEMPERATURES ON THURSDAY SHOWING LITTLE TO NO DIURNAL CHANGE OR EVEN
SOME FALLING TEMPERATURES. HIGHS WILL BE IN THE 40S.
IN THE EXTENDED...BROAD UPPER LEVEL TROUGHING SETTLES OVER THE
CENTRAL STATES AND WILL KEEP COOL AND DRY CONDITIONS IN PLACE INTO
THE END OF THE WEEK. MODELS ARE IN DECENT AGREEMENT WITH THIS DRY
AND COLD PATTERN WHICH PLACE WITH HIGHS ONLY IN THE UPPER 30S TO MID
40S AND LOWS IN THE 20S. MODELS DO DIVERGE A BIT FOR THE WEEKEND
WITH A MORE ZONAL MID LEVEL PATTERN IN THE GFS BRINGING A WAVE
THROUGH THE MISSOURI VALLEY ON SUNDAY. MEANWHILE THE ECMWF ALSO
HINTS AT A WAVE...BUT DROPS IT THROUGH SOUTHWEST MINNESOTA. DID ADD
A SLIGHT CHANCE POP IN OUR NORTHEAST FOR SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
920 AM CDT TUE OCT 23 2012
.DISCUSSION.../ISSUED AT 920 AM CDT/
DENSE FOG PERSISTING ACROSS NORTHEAST QUARTER OF THE FORECAST AREA
LONGER THAN EARLIER ANTICIPATED. FOR NOW...HAVE EXTENDED DENSE FOG
ADVISORY FOR SOUTHWEST MINNESOTA AND I-29 CORRIDOR FROM SIOUX FALLS
NORTHWARD UNTIL 10 AM...THOUGH HRRR SUGGESTS LOW VISIBILITY MAY LAST
EVEN LONGER THAN THAT...ESPECIALLY ALONG AND WEST/UPSLOPE OF BUFFALO
RIDGE. WILL CONTINUE TO EVALUATE THAT OVER THE NEXT HOUR AND ADJUST
AGAIN IF NECESSARY PRIOR TO 15Z. FOG/STRATUS WILL HOLD TEMPERATURES
DOWN ACCORDINGLY...AND HAVE BEGUN TO TREND AFTERNOON READINGS LOWER
ACROSS THE NORTHEAST CWA...THOUGH AGAIN...FURTHER ADJUSTMENTS MAY BE
NECESSARY IF FOG PERSISTS LATER INTO THE MORNING. LEFT HIGHS IN THE
70S ALONE ACROSS THE SOUTHWEST CWA...AS MODELS STILL SHOW BOUNDARY
AND ASSOCIATED SHIFT TO SOUTHWEST LOW LEVEL FLOW PUSHING INTO THAT
AREA DURING THE AFTERNOON. THIS SHOULD ALLOW DECENT DRYING/MIXING IN
AREAS WEST OF THE JAMES VALLEY.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
AVIATION FORECAST FOR THE TAF SITES CONTINUE TO SHOW BELOW NORMAL
CONFIDENCE IN THE DETAILS. OBSERVATION HAS DROPPED OUT AT KHON AND
WEB CAMS DO NOT SHOW FOG HAS SET IN THERE. SATELLITE INDICATES LOWER
CLOUDS HAVE WORKED INTO THE AREA...BUT NOT SURE AT WHAT HEIGHT. AS
SUCH...HAVE ADDED NO AMENDMENT NOTE TO KHON TAF UNTIL OBSERVATION
EQUIPMENT IS FIXED. WIDESPREAD DENSE FOG HAS SET IN EAST OF THE
JAMES RIVER VALLEY IN EASTERN SOUTH DAKOTA INTO SOUTHWEST MINNESOTA
AND NORTHWEST IOWA. FOG AND LOW CEILINGS WILL BE STUBBORN TO LEAVE
AHEAD OF AN APPROACHING COLD FRONT...AND MOST LIKELY WILL NOT MIX
OUT AT KSUX. KFSD WAS A TOUGH CALL BUT FOR NOW HAVE THEM BREAKING
OUT IMMEDIATELY AHEAD OF THE FRONT. IF TRENDS CONTINUES...THE BREAK
IN MVFR TO IFR CONDITIONS MAY NOT COME TILL AFTER 24/03Z WHEN THE
COLD FRONT MOVES THROUGH. LIGHT NORTH FLOW TRANSITIONING TO
NORTHEAST IS EXPECTED BEHIND THE FRONT.
&&
.PREV DISCUSSION.../ISSUED AT 420 AM CDT/
BROAD SWATH OF STRATUS BLANKETING MUCH OF THE NORTHERN AND CENTRAL
PLAINS REMAINS THE PRIMARY CONCERN FOR TODAY. MODELS HOLD ONTO THE
LOW LEVEL MOISTURE THROUGH MUCH OF THE MORNING RESULTING IN THE
WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE AND FOG WILL LIKELY STICK
AROUND THROUGH MID TO LATE MORNING. SOUTHWESTERLY FLOW WILL BEGIN TO
INCREASE ACROSS THE WEST LATER THIS MORNING WHICH SHOULD BEGIN
MIXING DRIER AIR INTO THE LOW LEVELS WHICH SHOULD SCOUR OUT THE
CLOUDS BY AFTERNOON. THE BIG QUESTION IS HOW QUICKLY THE CLEARING
WILL WORK INTO OUR EASTERN HALF AND WHETHER OUR FAR NORTHEAST WILL
SEE SIGNIFICANT CLEARING BY LATE AFTERNOON. THIS WILL LARGE
IMPLICATIONS ON TEMPERATURE TRENDS...AS HEFTY WARM AIR ADVECTION
WILL EASILY PLACE HIGH TEMPERATURES IN THE MID TO UPPER 70S IN THE
WEST. DID KNOCK BACK HIGHS SLIGHTLY TO THE UPPER 60S IN OUR
NORTHEAST GIVEN THE POTENTIAL TO BE CLOUDY FOR THE BETTER PART OF
THE DAYLIGHT HOURS.
THE MILDER TEMPERATURES WILL BE SHORT LIVED AS A LARGE UPPER LEVEL
LOW TRACKS INTO THE SOUTHERN CANADIAN PRAIRIE PROVINCES BY WEDNESDAY
AND DROPS A COLD FRONT THROUGH THE NORTHERN PLAINS. THE SURFACE
FRONT DIGS THROUGH THE FORECAST AREA TUESDAY AFTERNOON AND TUESDAY
NIGHT THEN STALLS JUST SOUTH OF THE FORECAST AREA WITH LITTLE IMPACT
OUTSIDE OF SOME INCREASED CLOUD COVERAGE. ON WEDNESDAY...SURFACE LOW
PRESSURE DEVELOPS IN EASTERN KANSAS AND PUSHES NORTHEAST INTO
WESTERN IOWA LATE IN THE DAY. THE PRECISE TIMING OF THIS FEATURE AND
THE POTENTIAL LIFTING OF THE WARM FRONT INTO OUR SOUTHEASTERN
COUNTIES ARE STILL A BIT UNCERTAIN. HOWEVER...WITH INCREASED SHEAR
AND NAM MUCAPE APPROACHING 2000 J/KG NEAR THE BOUNDARY...COULD SEE
SOME THUNDERSTORM ACTIVITY IN ADDITION TO SHOWERS. A LARGE DETERRENT
TO ANY SURFACED BASED/SEVERE CONVECTION WILL BE THE STRONG CAPPING
IN PLACE IN THIS AREA. A SECOND AREA TO WATCH FOR POTENTIAL
PRECIPITATION ON WEDNESDAY WILL BE ACROSS THE FAR WESTERN CWA...WITH
STRONG 850 MB FRONTOGENESIS SETTING UP ACROSS CENTRAL AND
NORTHEASTERN SOUTH DAKOTA. WILL KEEP CHANCEY POPS IN PLACE FOR THE
DAY WITH LARGE UNCERTAINTY WITH THE BOUNDARY PLACEMENTS AND
CONDITIONAL CONVECTIVE POTENTIAL.
THE MID LEVEL TROUGH STARTS KICKING EASTWARD WEDNESDAY NIGHT WITH
THE MID LEVEL FRONTOGENESIS SHIFTING INTO OUR CENTRAL CWA BY
DAYBREAK THURSDAY. IT LOOKS LIKE A VERY STRONG POTENTIAL FOR SOME
DECENT RAINFALL WEDNESDAY NIGHT AND EARLY THURSDAY AND HAVE BOOSTED
POPS TO CATEGORICAL FOR THE CENTRAL AND EASTERN CWA. RAINFALL
AMOUNTS OF AROUND A QUARTER TO HALF INCH LOOK REASONABLE AT THIS
POINT. MUCH COOLER TEMPERATURES WILL ARRIVE DURING THIS TIME...WITH
TEMPERATURES ON THURSDAY SHOWING LITTLE TO NO DIURNAL CHANGE OR EVEN
SOME FALLING TEMPERATURES. HIGHS WILL BE IN THE 40S.
IN THE EXTENDED...BROAD UPPER LEVEL TROUGHING SETTLES OVER THE
CENTRAL STATES AND WILL KEEP COOL AND DRY CONDITIONS IN PLACE INTO
THE END OF THE WEEK. MODELS ARE IN DECENT AGREEMENT WITH THIS DRY
AND COLD PATTERN WHICH PLACE WITH HIGHS ONLY IN THE UPPER 30S TO MID
40S AND LOWS IN THE 20S. MODELS DO DIVERGE A BIT FOR THE WEEKEND
WITH A MORE ZONAL MID LEVEL PATTERN IN THE GFS BRINGING A WAVE
THROUGH THE MISSOURI VALLEY ON SUNDAY. MEANWHILE THE ECMWF ALSO
HINTS AT A WAVE...BUT DROPS IT THROUGH SOUTHWEST MINNESOTA. DID ADD
A SLIGHT CHANCE POP IN OUR NORTHEAST FOR SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ071-072-
080-081-089-090-097-098.
NE...NONE.
SD...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR SDZ040-056-
062.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1110 PM CDT MON OCT 22 2012
.DISCUSSION.../ISSUED AT 1018 PM CDT/
FORECAST GENERALLY LOOKS IN GOOD SHAPE TONIGHT. EXPECT CLOUDY SKIES
TO PERSIST THROUGH THE NIGHT...WITH THE CLOUD DECK LOWERING BY
MORNING. AREAS OF DRIZZLE AND FOG SHOULD EXPAND LATER TONIGHT AS
WELL. TRICKY FORECAST FOR TUESDAY. SOME OF THE NEWER GUIDANCE IS
SUGGESTING CLOUDS WILL BE SLOWER TO ERODE THAN PREVIOUSLY FORECAST.
THUS DELAYED CLEARING SOME AND EXTENDED THE DRIZZLE AND FOG INTO MID
MORNING. WILL EVENTUALLY SEE CLEARING FROM WEST TO EAST THROUGH THE
AFTERNOON...WITH EXACT TIMING HAVING BIG IMPLICATIONS ON HIGH
TEMPERATURES. DECIDED TO LEAVE HIGH TEMPERATURE FORECAST AS IS FOR
NOW. BUT LATEST NAM AND RAP WOULD SUGGEST THE SLOWER EROSION OF
CLOUDS COULD KEEP HIGHS FIVE TO TEN DEGREES COOLER THAN CURRENT
FORECAST ALONG AND EAST OF INTERSTATE 29. MEANWHILE MOST SREF
MEMBERS ARE LESS AGGRESSIVE WITH THE COOLER TEMPERATURES. THUS WILL
LET MIDNIGHT SHIFT EVALUATE FURTHER AND MAKE NECESSARY ADJUSTMENTS.
/CHENARD
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
AVIATION FORECAST FOR THE TAF SITES CONTINUE TO SHOW BELOW NORMAL
CONFIDENCE IN THE DETAILS. CURRENTLY...CEILINGS ARE ALL OVER THE MAP
IN REGARDS TO CATEGORY...RANGING ANYWHERE FROM VFR TO IFR. MOST OF
THE IFR CEILINGS ARE BOTTLED UP IN PARTS OF SOUTHWEST MN. BUT ALONG
THE I 29 CORRIDOR...MANY OF THE LOWER CLOUDS HAVE SCATTERED OUT
CREATING VFR CONDITIONS...ONLY TO GO BACK TO MVFR IN THE JAMES RIVER
VALLEY AND POINTS WESTWARD. IN GENERAL...A WEAK WIND SHIFT TO THE
SOUTH WILL LIKELY EDGE NORTHWARD TO THE I 90 CORRIDOR BY DAYBREAK
TUESDAY. PLENTY OF IFR AND LIFR CONDITIONS EXIST IN EASTERN
NEBRASKA. THEREFORE CONTINUE TO BE WORRIED THAT A LOWERING OF
CEILINGS AND VISIBILITIES WILL BE IN STORE FOR OUR AREA LATE TONIGHT
AND EARLY TUESDAY WITH SOME LOCATIONS INTO THE IFR CATEGORY. ON
TUESDAY...THERE WILL BE CLEARING BUT WITH WIND SPEEDS NOT OVERLY
STRONG OUT OF THE SOUTH...THE CLEARING WILL LIKELY BE DELAYED UNTIL
THE AFTERNOON FOR MANY AREAS. IN ADDITION...THE NEXT COLD FRONT ALSO
LOOKS SLOWER SO BACKED OFF ON THE WIND SHIFT TO THE NORTHWEST
SEVERAL HOURS. /MJF
&&
.PREVIOUS DISCUSSION...
PRIMARY FORECAST CONCERNS ARE DRIZZLE/FOG SCENARIO TONIGHT...PRECIP
CHANCES MIDWEEK...THEN BELOW NORMAL TEMPERATURES INTO THE WEEKEND.
TONIGHT...FORECASTER CONFIDENCE: MODERATE.
A BROAD AREA OF LOW PRESSURE WILL DEVELOP OVER THE NRN PLAINS
AHEAD OF A SEASONABLY STRONG UPPER LEVEL TROUGH MOVING THROUGH THE
INTERMOUNTAIN WEST. ALTHOUGH LARGE SCALE ASCENT WILL BE RATHER
WEAK OVERNIGHT...THE COMBINATION OF PLENTIFUL BOUNDARY LAYER
MOISTURE /SPEC HUMIDITY AOA 8 G/KG/ AND WEAK LOW LEVEL LIFT IS
EXPECTED TO PRODUCE AREAS OF FOG/DRIZZLE OVER PORTIONS OF THE AREA.
NOT EXPECTING MUCH IN THE WAY OF QPF /MAYBE A COUPLE HUNDREDTHS/
HOWEVER DO BELIEVE A FEW AREAS ALONG AND EAST OF THE JAMES VALLEY
WILL SEE MEASURABLE RAINFALL. FOG MAY ALSO BE A CONCERN...BUT
DIFFICULT TO PINPOINT HOW DENSE IT MAY GET. FUTURE SHIFTS WILL HAVE
MONITOR VSBY TRENDS.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE: LOW TO MODERATE.
RESIDUAL STRATUS/FOG/DRIZZLE IS LIKELY EARLY TUESDAY
MORNING...BEFORE AN INCREASING S/SWLY LOW LEVEL FLOW GRADUALLY
NUDGES THE STRATUS DECK NORTH/EAST OF THE FORECAST AREA. MODELS CAN
STRUGGLE WITH THE EROSION/MOVEMENT OF STRATUS SO THERE IS SOME
UNCERTAINTY HOW QUICKLY CLOUDS MAY ERODE. ATTM...MODEL CONSENSUS
PUSHES HIGHER LOW LEVEL RH VALUES OUT BETWEEN 15-18Z TUE AND THIS
SEEMS REASONABLE. WILL CONTINUE TO BANK ON SEEING AT LEAST PARTLY
CLOUDY SKIES TUESDAY...WHICH WHEN COMBINED WITH H8 TEMPS +13 TO +18C
RANGE SHOULD ALLOW FOR VERY MILD TEMPS IN THE 70S TO NEAR 80F.
INCREASING CLOUDS ARE LIKELY TUESDAY NIGHT...BUT WILL MAINTAIN DRY
CONDITIONS FOR NOW.
WEDNESDAY THROUGH THURSDAY...FORECASTER CONFIDENCE: MODERATE TO HIGH.
UPPER TROUGH WILL MOVE SLOWLY ACROSS THE REGION BEGINNING ON
WEDNESDAY. STRONGEST UPPER LEVEL FORCING /Q-VECTOR CONVERGENCE AND
FGEN/ LOOKS TO REMAIN PRIMARILY NORTH OF THE AREA DURING THE DAY ON
WEDNESDAY...ALTHOUGH WILL MAINTAIN LOW POPS AS THERE IS SOME
UNCERTAINTY REGARDING TIMING OF PRECIPITATION. THE BRUNT OF
FORCING/SATURATION WILL AFFECT THE AREA ON WEDNESDAY NIGHT AND
EARLY THURSDAY DUE TO A COMBINATION OF UPPER LEVEL DIVERGENCE AND
A MODERATE MID-LEVEL FRONTOGENETIC ZONE. QPF AMOUNTS STILL A BIT
TRICKY TO PIN DOWN AT THIS TIMEFRAME...BUT MODEL CONSENSUS
INDICATES THAT 0.25"-0.50" IS POSSIBLE...WITH LOCALLY HIGHER
AMOUNTS. FROPA IS PROGGED TO BE A BIT QUICKER IN 12Z SUITE OF
MODELS...SO BEGAN TO TAPER PRECIP CHANCES SIGNIFICANTLY AFTER 18Z
THURSDAY. TEMPS SHOULD BE NEAR NORMAL WED...COOLING ON THURSDAY
BEHIND THE FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...
SURFACE HIGH PRESSURE AND A COLD ARCTIC AIR AIRMASS WILL FILTER
INTO THE REGION LATE IN THE WEEK...RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH THE REMAINDER OF THE LONG TERM PERIOD. ONLY
REAL CHANCES FOR PRECIPITATION WILL BE ASSOCIATED WITH ANOTHER
SERIES OF UPPER LEVEL DISTURBANCES WHICH WILL MOVE ACROSS THE
REGION OVER LATE THIS WEEKEND.
MF/KS
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
653 PM PDT Wed Oct 24 2012
.SYNOPSIS...A band of rain and mountain snow will move through the
area today and tonight. The weather will generally be quiet on
Thursday before the next weather system arrives Friday with
additional storms for the weekend. More precipitation is expected
into early next week.
&&
.DISCUSSION...
Evening update: The wave of moisture and associated stratiform
precipitation has moved into the northern mountains and arcs back
into the Idaho Panhandle and Palouse. There is a distinct
mesoscale circulation beginning to bring a weak comma head to the
stratiform band over northern Lincoln County/Southern Ferry/Stevens.
This was well modeled per previous runs of the HRRR and should
help to enhance an area of QPF over the Nrn mtns arnd 6z. As such,
I have incr QPF amts slightly. In addition, we have made some
changes to the winter weather advisory which includes removing the
area south of Lake Chelan and starting the highlights for the
northern and eastern mountains now.
Satellite and CAMS confirms that pcpn has become more showery and
very light in the southern Cascades with the passage of the
shortwave trough axis but snow is beginning to accumulate on Loup
Loup Pass. Radar is slowly filling in on the central Idaho
Panhandle Mtns and CAMS frm Sherman Pass already show accumulating
snows so went ahead and started the highlights now.
Behind the stratiform pcpn, the upper-level cold is moving back in
with several upstream vorticity maximums. While most guidance is
dry, this is a low confidence fcst based on how steep lapse rates
will become and potential for any of these features to stir things
up. At this time, we will be watching one tracking through the
Nrn Blues and lower ID Panhandle bringing the next round of
showers arnd 3AM or slightly after. /sb
&&
.AVIATION...
00Z TAFS: Another round of rain and mtn snow is currently moving
through the region and will continue to moisten an already juicy
boundary layer. Consequently, expect widespread mtn obscurations
along the northern mtns this evening and overnight. All terminals
are expected to lower to MVFR/IFR levels either with the onset of
pcpn or after the rain ends and skies briefly clear. Confidence on
a whole is low for all sites given a wide array of MOS solutions
per each TAF site. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 34 41 32 45 / 100 20 10 50 40 40
Coeur d`Alene 31 43 33 41 32 44 / 90 50 10 50 40 40
Pullman 29 41 32 40 33 48 / 70 40 10 60 40 40
Lewiston 34 47 35 45 37 52 / 80 30 10 60 30 30
Colville 33 45 29 44 31 47 / 100 50 10 50 40 40
Sandpoint 30 41 30 41 32 44 / 100 60 10 40 40 50
Kellogg 32 38 26 38 31 43 / 90 60 20 50 60 50
Moses Lake 28 47 34 45 33 49 / 0 10 10 40 20 30
Wenatchee 31 47 35 44 35 47 / 10 10 10 40 20 30
Omak 31 46 33 46 34 48 / 90 10 10 50 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT Thursday for Central
Panhandle Mountains-Northern Panhandle.
WA...Winter Weather Advisory until 11 AM PDT Thursday for Northeast
Mountains-Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for East
Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1227 PM CDT TUE OCT 23 2012
.SHORT TERM...TODAY THROUGH THURSDAY
350 AM CDT TUE OCT 23 2012
AT 3 AM...A WARM FRONT EXTENDED FROM SIOUX CITY IOWA /KSUX/ TO
MUSCATINE IOWA /KMUT/. THERE IS LITTLE WEATHER ASSOCIATED WITH
THIS FRONT. MEANWHILE FURTHER NORTH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WERE DEVELOPING ALONG A BAND OF 900 TO 800 MB
FRONTOGENESIS ACROSS SOUTHEAST MINNESOTA. THE RUC SHOWS THAT THIS
BAND OF FRONTOGENESIS LIFTS QUICKLY NORTHEAST OF THE INTERSTATE 90
CORRIDOR AND BY LATE MORNING IT EXTENDS FROM HUDSON WISCONSIN TO
MILWAUKEE. THE MESO MODELS SEEM TO HAVE A FAIRLY GOOD HANDLE ON
THIS...SO FOLLOWED THEM. FURTHER SOUTHEAST...A SHORT WAVE TROUGH
WILL BE LIFTING NORTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY
INTO THE LOWER GREAT LAKES. THERE IS MODERATE 850 MB MOISTURE INTO
PARTS OF OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN THROUGHOUT THIS
MORNING...SO KEPT A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
IN THESE AREAS THROUGHOUT THIS MORNING.
FOR THIS AFTERNOON...WEAK 300K ISENTROPIC LIFT CONTINUES NORTH OF
THE WARM FRONT NORTH OF THE INTERSTATE 94 CORRIDOR. AS A
RESULT...KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR THIS AREA.
FOR TONIGHT...THE 23.00Z MODELS ARE IN GENERAL AGREEMENT THAT
THERE WILL BE WEAK TO MODERATE 850 MOISTURE TRANSPORT INTO THE
REGION. THE MESO MODELS /ARW...NMM...AND SPC WRF/ SUGGEST THAT
THERE WILL BE SOME ISOLATED SHOWERS AND THUNDERSTORMS...SO KEPT
THE 20 PERCENT PROBABILITY OF RAIN ACROSS THE ENTIRE AREA.
ON WEDNESDAY...THE MODELS ARE IN GENERAL AGREEMENT THAT A WARM AIR
MASS BETWEEN 850 MB AND 675 MB WILL ADVECT NORTHWARD IN ADVANCE OF
AN APPROACHING COLD FRONT. THIS CAP SHOULD GREATLY INHIBIT THE
DEVELOPMENT OF PRECIPITATION AHEAD OF THE APPROACHING COLD FRONT
FOR MUCH OF THE DAY...THUS WENT DRY IN THE MORNING...AND SLOWLY
INCREASED THE PRECIPITATION CHANCES ACROSS NORTHEAST
IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL AND NORTH-CENTRAL
WISCONSIN. THINKING THAT THE STRONG CAP WILL LIMIT ANY SHOWER AND
THUNDERSTORM DEVELOPMENT TO ALONG AND JUST AHEAD OF THE COLD
FRONT. THE 0-6 KM BULK SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF
SUPERCELL THUNDERSTORM DEVELOPMENT. THE GFS GENERATES SOME LIGHT
SHOWERS AHEAD OF THIS FRONT...THUS...ITS MLCAPES ARE RUNNING
BETWEEN 1000 AND 1500 J/KG. MEANWHILE THE NAM/WRF IS DRY AND
ALLOWS TEMPERATURES TO CLIMB TO AROUND 80. THE COMBINATION OF
THESE TEMPERATURES AND MID 60 DEW POINTS /HIGHEST THIS LATE IN THE
YEAR SINCE OCTOBER 26 2010/ WILL RESULT IN THE ML CAPES AROUND
2500 J/KG. INITIALLY THINKING THAT THE CONVECTION WILL START TO
DEVELOP ALONG THE FRONT BETWEEN 24.19 AND 24.21Z AS ELEVATED CELLS
AND THEN BECOME SURFACE BASED BETWEEN 24.21Z AND 25.00Z. THE NAM
HAS A WEAK LOW ALONG THIS FRONT WHICH HELPS INCREASE THE 0-1KM
BULK SHEAR WHICH MAY POSSIBLY RESULT IN ISOLATED TORNADOES ACROSS
NORTH-CENTRAL IOWA AND SOUTH-CENTRAL AND SOUTHEAST MINNESOTA.
OTHERWISE...THE MAIN SEVERE WEATHER THREATS WILL BE LARGE HAIL AND
DAMAGING WIND DURING THE LATE AFTERNOON AND EARLY EVENING ACROSS
NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL WISCONSIN.
ON THURSDAY...THE MODELS STILL DIFFER ON THE TIMING OF THE FRONT.
THE GFS IS THE SLOWEST AND LINGER PRECIPITATION ACROSS THE ENTIRE
AREA THROUGH THE DAY. MEANWHILE THE GEM IS THE FASTEST AND HAS THE
AFTERNOON DRY. DUE TO THESE DIFFERENCES...DID NOT GET TOO FANCY
WITH TRYING TO TIME THE PRECIPITATION OUT OF THE AREA.
REGARDLESS...THE MOST NOTICEABLE FEATURE WILL BE THE RAPIDLY
FALLING TEMPERATURES IN THE WAKE OF THE FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
350 AM CDT TUE OCT 23 2012
ON THURSDAY NIGHT...THE MODELS WERE IN GOOD CONSENSUS THAT THE
PRECIPITATION WOULD BE ENDING ACROSS WESTERN WISCONSIN DURING THE
EVENING. AS A RESULT...CONFINED THE PRECIPITATION CHANCES TO THAT
TIME PERIOD.
ON MONDAY...THE 23.00Z GFS WAS VERY SIMILAR WITH ITS 22.18Z RUN AT
GENERATING SOME WARM AIR ADVECTION PRECIPITATION ACROSS THE AREA.
MEANWHILE THE ECMWF CONTINUE TO SHOW THAT THIS PRECIPITATION WILL
DRY UP AS IT HEADS INTO THE AREA. DUE TO THESE DIFFERENCES
MENTIONED A SLIGHT CHANCE OF PRECIPITATION NORTH OF AN OELWEIN
IOWA TO MEDFORD WISCONSIN LINE. THE PRECIPITATION HAS THE
POTENTIAL OF BEING A MIX OF RAIN AND SNOW IN THE EARLY MORNING.
HOWEVER SINCE IT WAS VERY UNCLEAR IT WAS EVEN GOING TO
OCCUR...JUST OPTED TO GO WITH RAIN FOR NOW.
&&
.AVIATION...THIS AFTERNOON THRU WEDNESDAY MORNING
1227 PM CDT TUE OCT 23 2012
IFR CLOUDS/BR/FG ASSOCIATED WITH A WARM AND VERY MOIST AIRMASS...AND
A WARM FRONT...MOVING NORTH ACROSS THE UPPER MIDWEST LOOK TO PREVAIL
ACROSS THE AREA THIS PERIOD. CIGS/VSBYS STRUGGLING TO IMPROVE ACROSS
THE AREA AT MID-DAY AS THE WARM FRONT LIFTS SLOWLY NORTH INTO THE
AREA AND SFC-850MB MOISTURE CONTINUES TO INCREASE. SOME IMPROVEMENT
TO MVFR CIGS ACROSS NORTHERN IA BEHIND THE FRONT AT MID DAY. DID
SPREAD SOME MVFR CIGS INTO BOTH KRST/KLSE LATER THIS AFTERNOON WITH
THE FRONT EXPECTED TO LIFT NORTH OF I-90. HOWEVER...MORE LOWER END
MVFR AND IFR CLOUD DECKS BEHIND THE FRONT OVER CENTRAL/SOUTHERN IA
TO ADVECT NORTH TONIGHT...AND LOWER WITH DIURNAL COOLING. WITH FG/BR
FAILING TO CLEAR THIS AFTERNOON...STAGE IS SET FOR IFR/LIFR VSBYS IN
FOG TONIGHT AS THE LOW LEVEL MOISTURE CONTINUES TO INCREASE AND THE
AIRMASS COOLS. CARRIED IFR/LIFR CIGS/VSBYS AT BOTH KRST/KLSE IN THE
05Z-15Z TIME-FRAME TONIGHT. AREA MAY END UP COVERED WITH A DENSE FOG
ADVISORY FOR THIS TIME PERIOD. CONDITIONS LOOK SLOW TO IMPROVE WED
WITH LITTLE CHANGE OF THE AIRMASS AND BROAD LOW LEVEL WARM
ADVECTION/ASCENT OVER THE AREA...AHEAD OF A STRONG COLD FRONT TO
MOVE INTO THE AREA WED NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
350 AM CDT TUE OCT 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
631 AM CDT TUE OCT 23 2012
.SHORT TERM...TODAY THROUGH THURSDAY
350 AM CDT TUE OCT 23 2012
AT 3 AM...A WARM FRONT EXTENDED FROM SIOUX CITY IOWA /KSUX/ TO
MUSCATINE IOWA /KMUT/. THERE IS LITTLE WEATHER ASSOCIATED WITH
THIS FRONT. MEANWHILE FURTHER NORTH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WERE DEVELOPING ALONG A BAND OF 900 TO 800 MB
FRONTOGENESIS ACROSS SOUTHEAST MINNESOTA. THE RUC SHOWS THAT THIS
BAND OF FRONTOGENESIS LIFTS QUICKLY NORTHEAST OF THE INTERSTATE 90
CORRIDOR AND BY LATE MORNING IT EXTENDS FROM HUDSON WISCONSIN TO
MILWAUKEE. THE MESO MODELS SEEM TO HAVE A FAIRLY GOOD HANDLE ON
THIS...SO FOLLOWED THEM. FURTHER SOUTHEAST...A SHORT WAVE TROUGH
WILL BE LIFTING NORTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY
INTO THE LOWER GREAT LAKES. THERE IS MODERATE 850 MB MOISTURE INTO
PARTS OF OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN THROUGHOUT THIS
MORNING...SO KEPT A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
IN THESE AREAS THROUGHOUT THIS MORNING.
FOR THIS AFTERNOON...WEAK 300K ISENTROPIC LIFT CONTINUES NORTH OF
THE WARM FRONT NORTH OF THE INTERSTATE 94 CORRIDOR. AS A
RESULT...KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR THIS AREA.
FOR TONIGHT...THE 23.00Z MODELS ARE IN GENERAL AGREEMENT THAT
THERE WILL BE WEAK TO MODERATE 850 MOISTURE TRANSPORT INTO THE
REGION. THE MESO MODELS /ARW...NMM...AND SPC WRF/ SUGGEST THAT
THERE WILL BE SOME ISOLATED SHOWERS AND THUNDERSTORMS...SO KEPT
THE 20 PERCENT PROBABILITY OF RAIN ACROSS THE ENTIRE AREA.
ON WEDNESDAY...THE MODELS ARE IN GENERAL AGREEMENT THAT A WARM AIR
MASS BETWEEN 850 MB AND 675 MB WILL ADVECT NORTHWARD IN ADVANCE OF
AN APPROACHING COLD FRONT. THIS CAP SHOULD GREATLY INHIBIT THE
DEVELOPMENT OF PRECIPITATION AHEAD OF THE APPROACHING COLD FRONT
FOR MUCH OF THE DAY...THUS WENT DRY IN THE MORNING...AND SLOWLY
INCREASED THE PRECIPITATION CHANCES ACROSS NORTHEAST
IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL AND NORTH-CENTRAL
WISCONSIN. THINKING THAT THE STRONG CAP WILL LIMIT ANY SHOWER AND
THUNDERSTORM DEVELOPMENT TO ALONG AND JUST AHEAD OF THE COLD
FRONT. THE 0-6 KM BULK SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF
SUPERCELL THUNDERSTORM DEVELOPMENT. THE GFS GENERATES SOME LIGHT
SHOWERS AHEAD OF THIS FRONT...THUS...ITS MLCAPES ARE RUNNING
BETWEEN 1000 AND 1500 J/KG. MEANWHILE THE NAM/WRF IS DRY AND
ALLOWS TEMPERATURES TO CLIMB TO AROUND 80. THE COMBINATION OF
THESE TEMPERATURES AND MID 60 DEW POINTS /HIGHEST THIS LATE IN THE
YEAR SINCE OCTOBER 26 2010/ WILL RESULT IN THE ML CAPES AROUND
2500 J/KG. INITIALLY THINKING THAT THE CONVECTION WILL START TO
DEVELOP ALONG THE FRONT BETWEEN 24.19 AND 24.21Z AS ELEVATED CELLS
AND THEN BECOME SURFACE BASED BETWEEN 24.21Z AND 25.00Z. THE NAM
HAS A WEAK LOW ALONG THIS FRONT WHICH HELPS INCREASE THE 0-1KM
BULK SHEAR WHICH MAY POSSIBLY RESULT IN ISOLATED TORNADOES ACROSS
NORTH-CENTRAL IOWA AND SOUTH-CENTRAL AND SOUTHEAST MINNESOTA.
OTHERWISE...THE MAIN SEVERE WEATHER THREATS WILL BE LARGE HAIL AND
DAMAGING WIND DURING THE LATE AFTERNOON AND EARLY EVENING ACROSS
NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL WISCONSIN.
ON THURSDAY...THE MODELS STILL DIFFER ON THE TIMING OF THE FRONT.
THE GFS IS THE SLOWEST AND LINGER PRECIPITATION ACROSS THE ENTIRE
AREA THROUGH THE DAY. MEANWHILE THE GEM IS THE FASTEST AND HAS THE
AFTERNOON DRY. DUE TO THESE DIFFERENCES...DID NOT GET TOO FANCY
WITH TRYING TO TIME THE PRECIPITATION OUT OF THE AREA.
REGARDLESS...THE MOST NOTICEABLE FEATURE WILL BE THE RAPIDLY
FALLING TEMPERATURES IN THE WAKE OF THE FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
350 AM CDT TUE OCT 23 2012
ON THURSDAY NIGHT...THE MODELS WERE IN GOOD CONSENSUS THAT THE
PRECIPITATION WOULD BE ENDING ACROSS WESTERN WISCONSIN DURING THE
EVENING. AS A RESULT...CONFINED THE PRECIPITATION CHANCES TO THAT
TIME PERIOD.
ON MONDAY...THE 23.00Z GFS WAS VERY SIMILAR WITH ITS 22.18Z RUN AT
GENERATING SOME WARM AIR ADVECTION PRECIPITATION ACROSS THE AREA.
MEANWHILE THE ECMWF CONTINUE TO SHOW THAT THIS PRECIPITATION WILL
DRY UP AS IT HEADS INTO THE AREA. DUE TO THESE DIFFERENCES
MENTIONED A SLIGHT CHANCE OF PRECIPITATION NORTH OF AN OELWEIN
IOWA TO MEDFORD WISCONSIN LINE. THE PRECIPITATION HAS THE
POTENTIAL OF BEING A MIX OF RAIN AND SNOW IN THE EARLY MORNING.
HOWEVER SINCE IT WAS VERY UNCLEAR IT WAS EVEN GOING TO
OCCUR...JUST OPTED TO GO WITH RAIN FOR NOW.
&&
.AVIATION...TODAY AND TONIGHT
630 AM CDT TUE OCT 23 2012
A WARM FRONT CURRENTLY DRAPED ACROSS CENTRAL IOWA WILL LIFT
NORTHWARD TODAY. IFR CEILINGS/VISIBILITIES COMMON TO THE NORTH OF
THE FRONT AT BOTH TAF SITES. EXPECT THESE CONDITIONS TO CONTINUE
THROUGH MID MORNING...BEFORE CEILINGS AND VISIBILITIES IMPROVE.
CEILING HEIGHTS ARE EXPECTED TO RISE INTO THE MVFER CATEGORY
BETWEEN 14Z-16Z AND REMAIN THERE THROUGH THE REMAINDER OF THE TAF
PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
350 AM CDT TUE OCT 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
351 AM CDT TUE OCT 23 2012
.SHORT TERM...TODAY THROUGH THURSDAY
350 AM CDT TUE OCT 23 2012
AT 3 AM...A WARM FRONT EXTENDED FROM SIOUX CITY IOWA /KSUX/ TO
MUSCATINE IOWA /KMUT/. THERE IS LITTLE WEATHER ASSOCIATED WITH
THIS FRONT. MEANWHILE FURTHER NORTH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WERE DEVELOPING ALONG A BAND OF 900 TO 800 MB
FRONTOGENESIS ACROSS SOUTHEAST MINNESOTA. THE RUC SHOWS THAT THIS
BAND OF FRONTOGENESIS LIFTS QUICKLY NORTHEAST OF THE INTERSTATE 90
CORRIDOR AND BY LATE MORNING IT EXTENDS FROM HUDSON WISCONSIN TO
MILWAUKEE. THE MESO MODELS SEEM TO HAVE A FAIRLY GOOD HANDLE ON
THIS...SO FOLLOWED THEM. FURTHER SOUTHEAST...A SHORT WAVE TROUGH
WILL BE LIFTING NORTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY
INTO THE LOWER GREAT LAKES. THERE IS MODERATE 850 MB MOISTURE INTO
PARTS OF OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN THROUGHOUT THIS
MORNING...SO KEPT A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
IN THESE AREAS THROUGHOUT THIS MORNING.
FOR THIS AFTERNOON...WEAK 300K ISENTROPIC LIFT CONTINUES NORTH OF
THE WARM FRONT NORTH OF THE INTERSTATE 94 CORRIDOR. AS A
RESULT...KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR THIS AREA.
FOR TONIGHT...THE 23.00Z MODELS ARE IN GENERAL AGREEMENT THAT
THERE WILL BE WEAK TO MODERATE 850 MOISTURE TRANSPORT INTO THE
REGION. THE MESO MODELS /ARW...NMM...AND SPC WRF/ SUGGEST THAT
THERE WILL BE SOME ISOLATED SHOWERS AND THUNDERSTORMS...SO KEPT
THE 20 PERCENT PROBABILITY OF RAIN ACROSS THE ENTIRE AREA.
ON WEDNESDAY...THE MODELS ARE IN GENERAL AGREEMENT THAT A WARM AIR
MASS BETWEEN 850 MB AND 675 MB WILL ADVECT NORTHWARD IN ADVANCE OF
AN APPROACHING COLD FRONT. THIS CAP SHOULD GREATLY INHIBIT THE
DEVELOPMENT OF PRECIPITATION AHEAD OF THE APPROACHING COLD FRONT
FOR MUCH OF THE DAY...THUS WENT DRY IN THE MORNING...AND SLOWLY
INCREASED THE PRECIPITATION CHANCES ACROSS NORTHEAST
IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL AND NORTH-CENTRAL
WISCONSIN. THINKING THAT THE STRONG CAP WILL LIMIT ANY SHOWER AND
THUNDERSTORM DEVELOPMENT TO ALONG AND JUST AHEAD OF THE COLD
FRONT. THE 0-6 KM BULK SHEAR IS FAVORABLE FOR THE DEVELOPMENT OF
SUPERCELL THUNDERSTORM DEVELOPMENT. THE GFS GENERATES SOME LIGHT
SHOWERS AHEAD OF THIS FRONT...THUS...ITS MLCAPES ARE RUNNING
BETWEEN 1000 AND 1500 J/KG. MEANWHILE THE NAM/WRF IS DRY AND
ALLOWS TEMPERATURES TO CLIMB TO AROUND 80. THE COMBINATION OF
THESE TEMPERATURES AND MID 60 DEW POINTS /HIGHEST THIS LATE IN THE
YEAR SINCE OCTOBER 26 2010/ WILL RESULT IN THE ML CAPES AROUND
2500 J/KG. INITIALLY THINKING THAT THE CONVECTION WILL START TO
DEVELOP ALONG THE FRONT BETWEEN 24.19 AND 24.21Z AS ELEVATED CELLS
AND THEN BECOME SURFACE BASED BETWEEN 24.21Z AND 25.00Z. THE NAM
HAS A WEAK LOW ALONG THIS FRONT WHICH HELPS INCREASE THE 0-1KM
BULK SHEAR WHICH MAY POSSIBLY RESULT IN ISOLATED TORNADOES ACROSS
NORTH-CENTRAL IOWA AND SOUTH-CENTRAL AND SOUTHEAST MINNESOTA.
OTHERWISE...THE MAIN SEVERE WEATHER THREATS WILL BE LARGE HAIL AND
DAMAGING WIND DURING THE LATE AFTERNOON AND EARLY EVENING ACROSS
NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND WEST-CENTRAL WISCONSIN.
ON THURSDAY...THE MODELS STILL DIFFER ON THE TIMING OF THE FRONT.
THE GFS IS THE SLOWEST AND LINGER PRECIPITATION ACROSS THE ENTIRE
AREA THROUGH THE DAY. MEANWHILE THE GEM IS THE FASTEST AND HAS THE
AFTERNOON DRY. DUE TO THESE DIFFERENCES...DID NOT GET TOO FANCY
WITH TRYING TO TIME THE PRECIPITATION OUT OF THE AREA.
REGARDLESS...THE MOST NOTICEABLE FEATURE WILL BE THE RAPIDLY
FALLING TEMPERATURES IN THE WAKE OF THE FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
350 AM CDT TUE OCT 23 2012
ON THURSDAY NIGHT...THE MODELS WERE IN GOOD CONSENSUS THAT THE
PRECIPITATION WOULD BE ENDING ACROSS WESTERN WISCONSIN DURING THE
EVENING. AS A RESULT...CONFINED THE PRECIPITATION CHANCES TO THAT
TIME PERIOD.
ON MONDAY...THE 23.00Z GFS WAS VERY SIMILAR WITH ITS 22.18Z RUN AT
GENERATING SOME WARM AIR ADVECTION PRECIPITATION ACROSS THE AREA.
MEANWHILE THE ECMWF CONTINUE TO SHOW THAT THIS PRECIPITATION WILL
DRY UP AS IT HEADS INTO THE AREA. DUE TO THESE DIFFERENCES
MENTIONED A SLIGHT CHANCE OF PRECIPITATION NORTH OF AN OELWEIN
IOWA TO MEDFORD WISCONSIN LINE. THE PRECIPITATION HAS THE
POTENTIAL OF BEING A MIX OF RAIN AND SNOW IN THE EARLY MORNING.
HOWEVER SINCE IT WAS VERY UNCLEAR IT WAS EVEN GOING TO
OCCUR...JUST OPTED TO GO WITH RAIN FOR NOW.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1139 PM CDT MON OCT 22 2012
THE SURFACE LOW HAS MOVE NORTH INTO WESTERN IOWA THIS EVENING AND
THE TWO WARM FRONTS HAVE CONSOLIDATED INTO ONE AND IT EXTENDS
FROM THE LOW ALONG THE I80 CORRIDOR. ISENTROPIC UP GLIDE OVER THE
FRONT HAS SLOWLY BEEN BRINGING THE CEILINGS DOWN ACROSS THE AREA
WITH IFR CONDITIONS ALREADY IN PLACE AT KRST. AS THE FRONT MOVES
NORTH OVERNIGHT...EXPECT TO SEE THE IFR CONDITIONS MOVE SLOWLY
NORTH AS WELL AND SPREAD INTO KLSE. SOME DRIZZLE OCCURRING NORTH
OF THE WARM FRONT ALONG WITH SOME FOG AND EXPECT THESE WILL IMPACT
THE TAF SITES AS WELL. WITH THE HIGHER ELEVATION AT KRST...EXPECT
THAT THEY WILL GO DOWN TO LIFR CONDITIONS UNTIL THE WARM FRONT
GOES THROUGH. THE VALLEY LOCATION AT KLSE SHOULD PROTECT IT A
LITTLE MORE AND WHILE THE CEILINGS WILL GO IFR EXPECTING THE
VISIBILITY TO STAY MVFR. ONCE THE WARM FRONT GOES THROUGH TUESDAY
MORNING THE WINDS WILL SWING AROUND TO THE SOUTHEAST OR SOUTH AND
INCREASE THE MIXING. THE DRIZZLE WILL END WITH THE PASSAGE OF THE
FRONT AND EXPECT TO SEE IMPROVEMENTS IN BOTH THE VISIBILITY AND
CEILINGS. THE VISIBILITY SHOULD GO UP TO VFR BY EARLY AFTERNOON
BUT THE 23.00Z NAM HOLDS ON THE LOW LEVEL MOISTURE BEHIND THE
FRONT. SO SIMILAR TO THE PREVIOUS FORECASTS...WILL TREND TOWARD A
MORE PESSIMISTIC FORECAST BY KEEPING THE CEILINGS MVFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
350 AM CDT TUE OCT 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1212 PM MDT TUE OCT 23 2012
.UPDATE...
AVIATION...18Z TAF ISSUANCE...FOG AND LOW CIGS HAVE LIFTED THIS
MORNING...WITH GUSTY WEST TO SOUTHWEST WINDS THE MAIN CONCERN
FOR TODAY. SE WYOMING TERMINALS WILL SEE GUSTS OF 30 OR 40
KNOTS WITH 20 TO 30 KTS ACROSS THE PANHANDLE AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE AREA AFTER 21Z. WINDS WILL SHIFT
TO THE NORTH AND THEN NORTHEAST BEHIND THE FRONT...AND SNOW WILL
DEVELOP AT KRWL...UP THROUGH KDGW AND TO THE NORTHEAST AFTER 03Z
OR SO AS THE NEXT STORM SYSTEM BEGINS TO IMPACT THE REGION. RJM
&&
.PREV DISCUSSION... /ISSUED 920 AM MDT TUE OCT 23 2012/
UPDATE...
WENT AHEAD AND LET THE HIGH WIND WARNING EXPIRE THIS MORNING AS
OBSERVED WINDS HAVE STAYED DOWN BELOW WARNING CRITERIA. THERE IS
STILL A CHANCE FOR WINDS TO BECOME STRONG AS WE MIX OUT...BUT DO
NOT THINK WE WILL HIT HIGH WIND WARNING CRITERIA ANY MORE TODAY.
STILL FAIRLY DENSE FOG OUT IN THE PANHANDLE AND WILL CONTINUE THE
SPS WE HAVE GOING THROUGH NOON. FOG MAY BURN OFF EARLIER THAN
THAT...BUT FOR NOW...WILL GO FOR NOON. DEFINITELY SOME QUESTIONS
ON THE UPCOMING WINTER EVENT THAT WE WILL NEED TO WORK OUT FOR THE
AFTERNOON PACKAGE. WAITING FOR THE 12Z MODEL RUNS TO MAKE ANY
DECISIONS ON HIGHLIGHTS.
CLAYCOMB
PREV DISCUSSION... /ISSUED 623 AM MDT TUE OCT 23 2012/
SHORT TERM...TODAY THROUGH THURSDAY...
LOTS OF FORECAST CONCERNS OVER THE SHORT TERM. WINDS HAVE BEEN
APPROACHING HIGH WIND CRITERIA IN THE ARLINGTON AREA OVER THE PAST
FEW HOURS...BUT HAVE GENERALLY REMAINED BELOW 50MPH. THE GFS SHOWS
700MB 50-60 KTS TO THE WEST OF THE LARAMIE RANGE THROUGH 12Z
BEFORE DECREASING TO 45 KTS BY 18Z. BELIEVE THAT THE LACK OF
MIXING IS KEEPING WIND GUSTS BELOW 50 KTS DESPITE THE FAVORABLE
SFC PRESSURE PATTERN AND STRONG WINDS JUST OFF THE SFC. WILL KEEP
THE HIGH WIND WARNING GOING THROUGH THE MORNING BUT CONDITIONS ARE
CURRENTLY LOOKING MARGINAL FOR WIDESPREAD HIGH WINDS OUTSIDE OF
ARLINGTON. THE SFC LOW CURRENTLY OVER NORTHERN WYOMING IS PROGGED
TO SHIFT EASTWARD INTO WESTERN SOUTH DAKOTA BY MIDDAY. THIS WILL
CAUSE LLVL FLOW TO GO MORE WESTERLY...BUT STILL EXPECT BREEZY-
TO-WINDY CONDITIONS TO CONTINUE ALONG AND WEST OF THE LARAMIE
RANGE WITH 700MB FLOW AT THE AFOREMENTIONED 30-40 KTS.
LOW CLOUDS AND FOG HAVE DEVELOPED OVER THE WESTERN NEBRASKA
PANHANDLE EARLY THIS MORNING. THE HRRR MODEL SHOWS LIFR CONDITIONS
PERSISTING THROUGH AROUND 15Z. SOME LOCATIONS ACROSS THE SOUTHERN
PANHANDLE HAVE REPORTED DENSE FOG. CURRENTLY HAVE AN SPS OUT TO
COVER THE DENSE FOG THREAT BUT MAY NEED TO CONSIDER AN ADVISORY IF
THE CONDITIONS PERSIST. WATER VAPOR IMAGERY SHOWS THE STRONG UPPER
LEVEL TROUGH CURRENTLY OVER THE WEST COAST WITH THE MOISTURE
STREAMING ACROSS WESTERN WY. THIS TROUGH WILL PROGRESS EASTWARD
OVER THE COURSE OF THE DAY WITH THE MOISTURE AND LIFT PRODUCING A
SLIGHT CHANCE OF SHOWERS OVER THE WESTERN ZONES BY AFTERNOON.
THE MAIN FORECAST CHALLENGE OVER THE SHORT TERM INVOLVES THE
POTENTIAL MAJOR WINTER STORM EVENT BEGINNING ON WEDNESDAY. THE
MODELS ARE IN AGREEMENT IN SHOWING THE LARGE SCALE TROUGH AXIS
BEING LOCATED OVER UTAH AND IDAHO ON WEDNESDAY AFTERNOON. A 125 KT
UPPER LEVEL JET IS SITUATED OVER WYOMING ON WEDNESDAY. A SW-NE
ORIENTED MIDLEVEL FRONTOGENESIS LINE DEVELOPS FROM RAWLINS TO
DOUGLAS BY MIDDAY WEDNESDAY. SNOW BECOMES LIKELY TO THE WEST OF THE
LARAMIE RANGE ON WEDNESDAY MORNING WITH 700MB TEMPS AROUND -4C. A
STRONG SHORTWAVE IN THE TROUGH IS FORECASTED TO MOVE OVER COLORADO
ON WEDNESDAY NIGHT. INCREASING LARGE SCALE LIFT AND UPPER LEVEL
DIVERGENCE WILL CAUSE WIDESPREAD SNOW TO DEVELOP MAINLY AFTER 00Z
THURS OVER THE PLAINS. IT IS THE 00Z-12Z PERIOD THAT SNOWFALL
RATES WILL BE HIGHEST IN SOUTHEAST WYOMING WITH EXCELLENT LARGE
SCALE UPWARD MOTION AND DEEP LAYERED SATURATION. THE SHORTWAVE
QUICKLY PROGRESSES EASTWARD INTO THE CENTRAL PLAINS ON THURS
MORNING WITH SNOWFALL RATES COMING DOWN SUBSTANTIALLY. THURS WILL
BE QUITE COLD FOR LATE OCTOBER WITH LLVL UPSLOPE AND 700MB TEMPS
AROUND -10C. WITH A LACK OF LARGE SCALE FORCING ON THURS...LIGHT
SNOW SHOWERS WILL LIKELY BE CONFINED TO THE MTNS AND FAVORED
UPSLOPE AREAS ALONG THE LARAMIE RANGE.
WITH REGARD TO WINTER WEATHER HIGHLIGHTS...DECIDED TO ISSUE A
WINTER STORM WATCH FOR AREAS ALONG THE LARAMIE RANGE AND THE
SIERRA MADRE AND SNOWY RANGES. HAVE THE WATCH CONTINUING THROUGH
THE 00Z FRI AS LIGHT SNOW WILL LIKELY CONTINUE THROUGH THURS
AFTN OVER THE HIGHER ELEVATIONS. FUTURE SHIFTS CAN DECIDE IF THE
HIGHLIGHTS SHOULD BE ENDED OVER LOWER ELEVATIONS AFTER THE
SNOWFALL RATES COME DOWN ON THURS MORNING AS THE MODELS ARE
SHOWING. SNOWFALL ACCUMULATIONS WILL LIKELY BE ON THE LOW END OF
WARNING CRITERIA WITH THIS EVENT. WINDS WILL NOT BE MUCH OF A
CONCERN WITH THIS SYSTEM...HOWEVER OCCASIONAL GUSTS TO 35 MPH WILL
BE POSSIBLE AS THE COLD FRONT MOVES ACROSS THE PLAINS ON WED
EVENING. MUCH WEAKER WINDS CWA-WIDE ON THURS AS THE SFC HIGH
PRESSURE SETTLES OVER THE PLAINS.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
LATEST MEDIUM RANGE MODEL OUTPUT OFFER FAIRLY SIMILAR SOLUTIONS
THROUGH THE WEEKEND WITH SOME DIVERGENCE NOTED EARLY NEXT WEEK.
INITIALLY...A TRAILING SHORTWAVE WILL ROUND THE BASE OF THE BROAD
TROUGH FROM NRN UTAH INTO COLORADO THURSDAY NIGHT.
MEANWHILE...UPSLOPE FLOW WILL PERSIST IN THE LLVLS PARTICULARLY FOR
LOCATIONS NEAREST THE LARAMIE RANGE. SO...WOULD EXPECT ANOTHER BOUT
OF LIGHT SNOW ON THURSDAY NIGHT ADDING ANOTHER INCH OR TWO TO THE
THE SNOWFALL TOTALS.
THE SHORTWAVE WILL ACCELERATE EAST OUT ONTO THE PLAINS FOR
FRIDAY...LEAVING NORTHWEST FLOW TO PREVAIL ACROSS THE CWFA. THERE
MAY BE SOME LIGHT SNOW OR FLURRIES CONTINUING MAINLY FOR OROGRAPHIC
AREAS ON FRIDAY MORNING...WITH A GRADUAL DRYING TREND DURING THE
AFTERNOON. TEMPERATURES WILL CONTINUE TO BE COLD ON FRIDAY WITH H7
TEMPERATURES REMAINING AROUND -10C. THIS WILL KEEP HIGH TEMPERATURES
IN THE 30S ACROSS THE AREA. FRANKLY WITH SNOW ON THE GROUND WOULD
NOT BE AT ALL SURPRISED TO ONLY SEE 20S AT SOME AREAS ON FRIDAY.
ON SATURDAY...THE LATEST GFS TRACKING ANOTHER SHORTWAVE INTO THE
AREA IN NORTHWEST FLOW. THE ECMWF/UKMET/GEM/GFES DO NOT SUPPORT SUCH
A SOLUTION...SO HAVE CONSIDER IT TO BE THE OUTLIER AND HAVE
DISCOUNTED. AS SUCH A DRY DAY IS IN STORE ON SATURDAY WITH
TEMPERATURES THAT WILL CLIMB INTO THE 30S AND 40S. WINDS WILL
INCREASE FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AS LLVL
GRADIENT TIGHTENS. SO EVEN THOUGH TEMPERATURES WILL BE SLIGHTLY
WARMER...THE WINDS WILL MAKE IT FEEL MUCH COOLER IN THESE AREAS.
NORTHWEST FLOW WILL CONTINUE ON SUNDAY. BUT THE ECMWF IS SHOWING THE
EARLY SIGNS OF ANTICYCLONIC FLOW DEVELOPING OVER THE AREA BY LATE
SUNDAY. COMPARATIVELY THE GFS MAINTAINS NORTHWEST FLOW OVR THE AREA
AS A RESULT OF A STRONGER TROUGH OVER WRN CANADA. THE GEM/UKMET
SOLUTIONS OVER A REASONABLE COMPROMISE BETWEEN THE GFS/ECMWF. IN ANY
CASE...EXPECT CONDITIONS TO REMAIN DRY WITH TEMPERATURES MODERATING
BACK INTO THE 50S AND 60S FOR THE SUNDAY THROUGH TUESDAY TIMEFRAME.
FIRE WEATHER...
A WINDY START TO THE DAY FOR AREAS WEST ALONG AND WEST OF THE
LARAMIE RANGE TODAY...AS GUSTS OF 40 TO 50 MPH HAVE BEEN COMMON.
THESE WINDS WILL CONTINUE THROUGH MUCH OF THE DAY BEFORE RELAXING
THIS EVENING AND OVERNIGHT. MEANWHILE...FOGGY CONDITIONS ACROSS THE
WESTERN PANHANDLE WILL PERSIST THROUGH MID/LATE MORNING BEFORE
LIFTING. ONE MORE WARM DAY IS IN STORE TODAY WITH HIGH TEMPERATURES
THAT WILL REACH THE 50S WEST OF THE LARAMIE RANGE AND 60S AND 70S
OUT ON THE EASTERN PLAINS. BIG CHANGES ARE ON THE WAY TOMORROW
HOWEVER...AS A COLD FRONT BEGINS TO PUSH THROUGH THE AREA.
PRECIPITATION WILL TRANSITION FROM RAIN TO SNOW THROUGH THE DAY AS
THE FRONT PROGRESSES SOUTH. PRECIPITATION WILL TURN TO ALL SNOW FOR
WEDNESDAY NIGHT AND THURSDAY. SIGNIFICANT ACCUMULATING SNOW IS
LOOKING INCREASINGLY POSSIBLE. MUCH COLDER AIR WILL FILTER IN FOR
THURSDAY AND FRIDAY AS WELL...WITH HIGHS ONLY CLIMBING INTO THE 20S
AND 30S.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM 6 AM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ103-WYZ105-WYZ110-WYZ112-WYZ114.
WINTER STORM WATCH FROM 6 PM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ106-WYZ115-WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
920 AM MDT TUE OCT 23 2012
.UPDATE...
WENT AHEAD AND LET THE HIGH WIND WARNING EXPIRE THIS MORNING AS
OBSERVED WINDS HAVE STAYED DOWN BELOW WARNING CRITERIA. THERE IS
STILL A CHANCE FOR WINDS TO BECOME STRONG AS WE MIX OUT...BUT DO
NOT THINK WE WILL HIT HIGH WIND WARNING CRITERIA ANY MORE TODAY.
STILL FAIRLY DENSE FOG OUT IN THE PANHANDLE AND WILL CONTINUE THE
SPS WE HAVE GOING THROUGH NOON. FOG MAY BURN OFF EARLIER THAN
THAT...BUT FOR NOW...WILL GO FOR NOON. DEFINITELY SOME QUESTIONS
ON THE UPCOMING WINTER EVENT THAT WE WILL NEED TO WORK OUT FOR THE
AFTERNOON PACKAGE. WAITING FOR THE 12Z MODEL RUNS TO MAKE ANY
DECISIONS ON HIGHLIGHTS.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 623 AM MDT TUE OCT 23 2012/
SHORT TERM...TODAY THROUGH THURSDAY...
LOTS OF FORECAST CONCERNS OVER THE SHORT TERM. WINDS HAVE BEEN
APPROACHING HIGH WIND CRITERIA IN THE ARLINGTON AREA OVER THE PAST
FEW HOURS...BUT HAVE GENERALLY REMAINED BELOW 50MPH. THE GFS SHOWS
700MB 50-60 KTS TO THE WEST OF THE LARAMIE RANGE THROUGH 12Z
BEFORE DECREASING TO 45 KTS BY 18Z. BELIEVE THAT THE LACK OF
MIXING IS KEEPING WIND GUSTS BELOW 50 KTS DESPITE THE FAVORABLE
SFC PRESSURE PATTERN AND STRONG WINDS JUST OFF THE SFC. WILL KEEP
THE HIGH WIND WARNING GOING THROUGH THE MORNING BUT CONDITIONS ARE
CURRENTLY LOOKING MARGINAL FOR WIDESPREAD HIGH WINDS OUTSIDE OF
ARLINGTON. THE SFC LOW CURRENTLY OVER NORTHERN WYOMING IS PROGGED
TO SHIFT EASTWARD INTO WESTERN SOUTH DAKOTA BY MIDDAY. THIS WILL
CAUSE LLVL FLOW TO GO MORE WESTERLY...BUT STILL EXPECT BREEZY-
TO-WINDY CONDITIONS TO CONTINUE ALONG AND WEST OF THE LARAMIE
RANGE WITH 700MB FLOW AT THE AFOREMENTIONED 30-40 KTS.
LOW CLOUDS AND FOG HAVE DEVELOPED OVER THE WESTERN NEBRASKA
PANHANDLE EARLY THIS MORNING. THE HRRR MODEL SHOWS LIFR CONDITIONS
PERSISTING THROUGH AROUND 15Z. SOME LOCATIONS ACROSS THE SOUTHERN
PANHANDLE HAVE REPORTED DENSE FOG. CURRENTLY HAVE AN SPS OUT TO
COVER THE DENSE FOG THREAT BUT MAY NEED TO CONSIDER AN ADVISORY IF
THE CONDITIONS PERSIST. WATER VAPOR IMAGERY SHOWS THE STRONG UPPER
LEVEL TROUGH CURRENTLY OVER THE WEST COAST WITH THE MOISTURE
STREAMING ACROSS WESTERN WY. THIS TROUGH WILL PROGRESS EASTWARD
OVER THE COURSE OF THE DAY WITH THE MOISTURE AND LIFT PRODUCING A
SLIGHT CHANCE OF SHOWERS OVER THE WESTERN ZONES BY AFTERNOON.
THE MAIN FORECAST CHALLENGE OVER THE SHORT TERM INVOLVES THE
POTENTIAL MAJOR WINTER STORM EVENT BEGINNING ON WEDNESDAY. THE
MODELS ARE IN AGREEMENT IN SHOWING THE LARGE SCALE TROUGH AXIS
BEING LOCATED OVER UTAH AND IDAHO ON WEDNESDAY AFTERNOON. A 125 KT
UPPER LEVEL JET IS SITUATED OVER WYOMING ON WEDNESDAY. A SW-NE
ORIENTED MIDLEVEL FRONTOGENESIS LINE DEVELOPS FROM RAWLINS TO
DOUGLAS BY MIDDAY WEDNESDAY. SNOW BECOMES LIKELY TO THE WEST OF THE
LARAMIE RANGE ON WEDNESDAY MORNING WITH 700MB TEMPS AROUND -4C. A
STRONG SHORTWAVE IN THE TROUGH IS FORECASTED TO MOVE OVER COLORADO
ON WEDNESDAY NIGHT. INCREASING LARGE SCALE LIFT AND UPPER LEVEL
DIVERGENCE WILL CAUSE WIDESPREAD SNOW TO DEVELOP MAINLY AFTER 00Z
THURS OVER THE PLAINS. IT IS THE 00Z-12Z PERIOD THAT SNOWFALL
RATES WILL BE HIGHEST IN SOUTHEAST WYOMING WITH EXCELLENT LARGE
SCALE UPWARD MOTION AND DEEP LAYERED SATURATION. THE SHORTWAVE
QUICKLY PROGRESSES EASTWARD INTO THE CENTRAL PLAINS ON THURS
MORNING WITH SNOWFALL RATES COMING DOWN SUBSTANTIALLY. THURS WILL
BE QUITE COLD FOR LATE OCTOBER WITH LLVL UPSLOPE AND 700MB TEMPS
AROUND -10C. WITH A LACK OF LARGE SCALE FORCING ON THURS...LIGHT
SNOW SHOWERS WILL LIKELY BE CONFINED TO THE MTNS AND FAVORED
UPSLOPE AREAS ALONG THE LARAMIE RANGE.
WITH REGARD TO WINTER WEATHER HIGHLIGHTS...DECIDED TO ISSUE A
WINTER STORM WATCH FOR AREAS ALONG THE LARAMIE RANGE AND THE
SIERRA MADRE AND SNOWY RANGES. HAVE THE WATCH CONTINUING THROUGH
THE 00Z FRI AS LIGHT SNOW WILL LIKELY CONTINUE THROUGH THURS
AFTN OVER THE HIGHER ELEVATIONS. FUTURE SHIFTS CAN DECIDE IF THE
HIGHLIGHTS SHOULD BE ENDED OVER LOWER ELEVATIONS AFTER THE
SNOWFALL RATES COME DOWN ON THURS MORNING AS THE MODELS ARE
SHOWING. SNOWFALL ACCUMULATIONS WILL LIKELY BE ON THE LOW END OF
WARNING CRITERIA WITH THIS EVENT. WINDS WILL NOT BE MUCH OF A
CONCERN WITH THIS SYSTEM...HOWEVER OCCASIONAL GUSTS TO 35 MPH WILL
BE POSSIBLE AS THE COLD FRONT MOVES ACROSS THE PLAINS ON WED
EVENING. MUCH WEAKER WINDS CWA-WIDE ON THURS AS THE SFC HIGH
PRESSURE SETTLES OVER THE PLAINS.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
LATEST MEDIUM RANGE MODEL OUTPUT OFFER FAIRLY SIMILAR SOLUTIONS
THROUGH THE WEEKEND WITH SOME DIVERGENCE NOTED EARLY NEXT WEEK.
INITIALLY...A TRAILING SHORTWAVE WILL ROUND THE BASE OF THE BROAD
TROUGH FROM NRN UTAH INTO COLORADO THURSDAY NIGHT.
MEANWHILE...UPSLOPE FLOW WILL PERSIST IN THE LLVLS PARTICULARLY FOR
LOCATIONS NEAREST THE LARAMIE RANGE. SO...WOULD EXPECT ANOTHER BOUT
OF LIGHT SNOW ON THURSDAY NIGHT ADDING ANOTHER INCH OR TWO TO THE
THE SNOWFALL TOTALS.
THE SHORTWAVE WILL ACCELERATE EAST OUT ONTO THE PLAINS FOR
FRIDAY...LEAVING NORTHWEST FLOW TO PREVAIL ACROSS THE CWFA. THERE
MAY BE SOME LIGHT SNOW OR FLURRIES CONTINUING MAINLY FOR OROGRAPHIC
AREAS ON FRIDAY MORNING...WITH A GRADUAL DRYING TREND DURING THE
AFTERNOON. TEMPERATURES WILL CONTINUE TO BE COLD ON FRIDAY WITH H7
TEMPERATURES REMAINING AROUND -10C. THIS WILL KEEP HIGH TEMPERATURES
IN THE 30S ACROSS THE AREA. FRANKLY WITH SNOW ON THE GROUND WOULD
NOT BE AT ALL SURPRISED TO ONLY SEE 20S AT SOME AREAS ON FRIDAY.
ON SATURDAY...THE LATEST GFS TRACKING ANOTHER SHORTWAVE INTO THE
AREA IN NORTHWEST FLOW. THE ECMWF/UKMET/GEM/GFES DO NOT SUPPORT SUCH
A SOLUTION...SO HAVE CONSIDER IT TO BE THE OUTLIER AND HAVE
DISCOUNTED. AS SUCH A DRY DAY IS IN STORE ON SATURDAY WITH
TEMPERATURES THAT WILL CLIMB INTO THE 30S AND 40S. WINDS WILL
INCREASE FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AS LLVL
GRADIENT TIGHTENS. SO EVEN THOUGH TEMPERATURES WILL BE SLIGHTLY
WARMER...THE WINDS WILL MAKE IT FEEL MUCH COOLER IN THESE AREAS.
NORTHWEST FLOW WILL CONTINUE ON SUNDAY. BUT THE ECMWF IS SHOWING THE
EARLY SIGNS OF ANTICYLONIC FLOW DEVELOPING OVER THE AREA BY LATE
SUNDAY. COMPARATIVELY THE GFS MAINTAINS NORTHWEST FLOW OVR THE AREA
AS A RESULT OF A STRONGER TROUGH OVER WRN CANADA. THE GEM/UKMET
SOLUTIONS OVER A REASONABLE COMPROMISE BETWEEN THE GFS/ECMWF. IN ANY
CASE...EXPECT CONDITIONS TO REMAIN DRY WITH TEMPERATURES MODERATING
BACK INTO THE 50S AND 60S FOR THE SUNDAY THROUGH TUESDAY TIMEFRAME.
AVIATION...12Z TAF ISSUANCE...
MAIN AVIATION CONCERN WILL BE THE FOG...SOME OF WHICH HAS BEEN
LOCALLY DENSE THAT HAS DEVELOPED ACROSS THE WESTERN NEBRASKA
AIRFIELDS THIS MORNING. THESE LOW CIGS WILL HANG ON UNTIL AROUND
15 OR 16Z BEFORE LIFTING. SE WYOMING TERMINALS WILL HAVE GUSTY
WINDS TO CONTEND WITH BY LATE THIS MORNING AND MORE SO DURING THE
AFTERNOON TIMEFRAME. EXPECT TO SEE THESE GUSTS APPROACH 30 OR 40
KNOTS THROUGH THIS PERIOD. SNOW WILL DEVELOP AT KRWL AFTER 03Z OR
SO...AS THE NEXT STORM SYSTEM BEGINS TO IMPACT THE REGION.
FIRE WEATHER...
A WINDY START TO THE DAY FOR AREAS WEST ALONG AND WEST OF THE
LARAMIE RANGE TODAY...AS GUSTS OF 40 TO 50 MPH HAVE BEEN COMMON.
THESE WINDS WILL CONTINUE THROUGH MUCH OF THE DAY BEFORE RELAXING
THIS EVENING AND OVERNIGHT. MEANWHILE...FOGGY CONDITIONS ACROSS THE
WESTERN PANHANDLE WILL PERSIST THROUGH MID/LATE MORNING BEFORE
LIFTING. ONE MORE WARM DAY IS IN STORE TODAY WITH HIGH TEMPERATURES
THAT WILL REACH THE 50S WEST OF THE LARAMIE RANGE AND 60S AND 70S
OUT ON THE EASTERN PLAINS. BIG CHANGES ARE ON THE WAY TOMORROW
HOWEVER...AS A COLD FRONT BEGINS TO PUSH THROUGH THE AREA.
PRECIPITATION WILL TRANSITION FROM RAIN TO SNOW THROUGH THE DAY AS
THE FRONT PROGRESSES SOUTH. PRECIPITATION WILL TURN TO ALL SNOW FOR
WEDNESDAY NIGHT AND THURSDAY. SIGNIFICANT ACCUMULATING SNOW IS
LOOKING INCREASINGLY POSSIBLE. MUCH COLDER AIR WILL FILTER IN FOR
THURSDAY AND FRIDAY AS WELL...WITH HIGHS ONLY CLIMBING INTO THE 20S
AND 30S.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM 6 AM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ103-WYZ105-WYZ110-WYZ112-WYZ114.
WINTER STORM WATCH FROM 6 PM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ106-WYZ115-WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM/AVIATION...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
623 AM MDT TUE OCT 23 2012
.SHORT TERM...TODAY THROUGH THURSDAY...
LOTS OF FORECAST CONCERNS OVER THE SHORT TERM. WINDS HAVE BEEN
APPROACHING HIGH WIND CRITERIA IN THE ARLINGTON AREA OVER THE PAST
FEW HOURS...BUT HAVE GENERALLY REMAINED BELOW 50MPH. THE GFS SHOWS
700MB 50-60 KTS TO THE WEST OF THE LARAMIE RANGE THROUGH 12Z
BEFORE DECREASING TO 45 KTS BY 18Z. BELIEVE THAT THE LACK OF
MIXING IS KEEPING WIND GUSTS BELOW 50 KTS DESPITE THE FAVORABLE
SFC PRESSURE PATTERN AND STRONG WINDS JUST OFF THE SFC. WILL KEEP
THE HIGH WIND WARNING GOING THROUGH THE MORNING BUT CONDITIONS ARE
CURRENTLY LOOKING MARGINAL FOR WIDESPREAD HIGH WINDS OUTSIDE OF
ARLINGTON. THE SFC LOW CURRENTLY OVER NORTHERN WYOMING IS PROGGED
TO SHIFT EASTWARD INTO WESTERN SOUTH DAKOTA BY MIDDAY. THIS WILL
CAUSE LLVL FLOW TO GO MORE WESTERLY...BUT STILL EXPECT BREEZY-
TO-WINDY CONDITIONS TO CONTINUE ALONG AND WEST OF THE LARAMIE
RANGE WITH 700MB FLOW AT THE AFOREMENTIONED 30-40 KTS.
LOW CLOUDS AND FOG HAVE DEVELOPED OVER THE WESTERN NEBRASKA
PANHANDLE EARLY THIS MORNING. THE HRRR MODEL SHOWS LIFR CONDITIONS
PERSISTING THROUGH AROUND 15Z. SOME LOCATIONS ACROSS THE SOUTHERN
PANHANDLE HAVE REPORTED DENSE FOG. CURRENTLY HAVE AN SPS OUT TO
COVER THE DENSE FOG THREAT BUT MAY NEED TO CONSIDER AN ADVISORY IF
THE CONDITIONS PERSIST. WATER VAPOR IMAGERY SHOWS THE STRONG UPPER
LEVEL TROUGH CURRENTLY OVER THE WEST COAST WITH THE MOISTURE
STREAMING ACROSS WESTERN WY. THIS TROUGH WILL PROGRESS EASTWARD
OVER THE COURSE OF THE DAY WITH THE MOISTURE AND LIFT PRODUCING A
SLIGHT CHANCE OF SHOWERS OVER THE WESTERN ZONES BY AFTERNOON.
THE MAIN FORECAST CHALLENGE OVER THE SHORT TERM INVOLVES THE
POTENTIAL MAJOR WINTER STORM EVENT BEGINNING ON WEDNESDAY. THE
MODELS ARE IN AGREEMENT IN SHOWING THE LARGE SCALE TROUGH AXIS
BEING LOCATED OVER UTAH AND IDAHO ON WEDNESDAY AFTERNOON. A 125 KT
UPPER LEVEL JET IS SITUATED OVER WYOMING ON WEDNESDAY. A SW-NE
ORIENTED MIDLEVEL FRONTOGENESIS LINE DEVELOPS FROM RAWLINS TO
DOUGLAS BY MIDDAY WEDNESDAY. SNOW BECOMES LIKELY TO THE WEST OF THE
LARAMIE RANGE ON WEDNESDAY MORNING WITH 700MB TEMPS AROUND -4C. A
STRONG SHORTWAVE IN THE TROUGH IS FORECASTED TO MOVE OVER COLORADO
ON WEDNESDAY NIGHT. INCREASING LARGE SCALE LIFT AND UPPER LEVEL
DIVERGENCE WILL CAUSE WIDESPREAD SNOW TO DEVELOP MAINLY AFTER 00Z
THURS OVER THE PLAINS. IT IS THE 00Z-12Z PERIOD THAT SNOWFALL
RATES WILL BE HIGHEST IN SOUTHEAST WYOMING WITH EXCELLENT LARGE
SCALE UPWARD MOTION AND DEEP LAYERED SATURATION. THE SHORTWAVE
QUICKLY PROGRESSES EASTWARD INTO THE CENTRAL PLAINS ON THURS
MORNING WITH SNOWFALL RATES COMING DOWN SUBSTANTIALLY. THURS WILL
BE QUITE COLD FOR LATE OCTOBER WITH LLVL UPSLOPE AND 700MB TEMPS
AROUND -10C. WITH A LACK OF LARGE SCALE FORCING ON THURS...LIGHT
SNOW SHOWERS WILL LIKELY BE CONFINED TO THE MTNS AND FAVORED
UPSLOPE AREAS ALONG THE LARAMIE RANGE.
WITH REGARD TO WINTER WEATHER HIGHLIGHTS...DECIDED TO ISSUE A
WINTER STORM WATCH FOR AREAS ALONG THE LARAMIE RANGE AND THE
SIERRA MADRE AND SNOWY RANGES. HAVE THE WATCH CONTINUING THROUGH
THE 00Z FRI AS LIGHT SNOW WILL LIKELY CONTINUE THROUGH THURS
AFTN OVER THE HIGHER ELEVATIONS. FUTURE SHIFTS CAN DECIDE IF THE
HIGHLIGHTS SHOULD BE ENDED OVER LOWER ELEVATIONS AFTER THE
SNOWFALL RATES COME DOWN ON THURS MORNING AS THE MODELS ARE
SHOWING. SNOWFALL ACCUMULATIONS WILL LIKELY BE ON THE LOW END OF
WARNING CRITERIA WITH THIS EVENT. WINDS WILL NOT BE MUCH OF A
CONCERN WITH THIS SYSTEM...HOWEVER OCCASIONAL GUSTS TO 35 MPH WILL
BE POSSIBLE AS THE COLD FRONT MOVES ACROSS THE PLAINS ON WED
EVENING. MUCH WEAKER WINDS CWA-WIDE ON THURS AS THE SFC HIGH
PRESSURE SETTLES OVER THE PLAINS.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
LATEST MEDIUM RANGE MODEL OUTPUT OFFER FAIRLY SIMILAR SOLUTIONS
THROUGH THE WEEKEND WITH SOME DIVERGENCE NOTED EARLY NEXT WEEK.
INITIALLY...A TRAILING SHORTWAVE WILL ROUND THE BASE OF THE BROAD
TROUGH FROM NRN UTAH INTO COLORADO THURSDAY NIGHT.
MEANWHILE...UPSLOPE FLOW WILL PERSIST IN THE LLVLS PARTICULARLY FOR
LOCATIONS NEAREST THE LARAMIE RANGE. SO...WOULD EXPECT ANOTHER BOUT
OF LIGHT SNOW ON THURSDAY NIGHT ADDING ANOTHER INCH OR TWO TO THE
THE SNOWFALL TOTALS.
THE SHORTWAVE WILL ACCELERATE EAST OUT ONTO THE PLAINS FOR
FRIDAY...LEAVING NORTHWEST FLOW TO PREVAIL ACROSS THE CWFA. THERE
MAY BE SOME LIGHT SNOW OR FLURRIES CONTINUING MAINLY FOR OROGRAPHIC
AREAS ON FRIDAY MORNING...WITH A GRADUAL DRYING TREND DURING THE
AFTERNOON. TEMPERATURES WILL CONTINUE TO BE COLD ON FRIDAY WITH H7
TEMPERATURES REMAINING AROUND -10C. THIS WILL KEEP HIGH TEMPERATURES
IN THE 30S ACROSS THE AREA. FRANKLY WITH SNOW ON THE GROUND WOULD
NOT BE AT ALL SURPRISED TO ONLY SEE 20S AT SOME AREAS ON FRIDAY.
ON SATURDAY...THE LATEST GFS TRACKING ANOTHER SHORTWAVE INTO THE
AREA IN NORTHWEST FLOW. THE ECMWF/UKMET/GEM/GFES DO NOT SUPPORT SUCH
A SOLUTION...SO HAVE CONSIDER IT TO BE THE OUTLIER AND HAVE
DISCOUNTED. AS SUCH A DRY DAY IS IN STORE ON SATURDAY WITH
TEMPERATURES THAT WILL CLIMB INTO THE 30S AND 40S. WINDS WILL
INCREASE FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AS LLVL
GRADIENT TIGHTENS. SO EVEN THOUGH TEMPERATURES WILL BE SLIGHTLY
WARMER...THE WINDS WILL MAKE IT FEEL MUCH COOLER IN THESE AREAS.
NORTHWEST FLOW WILL CONTINUE ON SUNDAY. BUT THE ECMWF IS SHOWING THE
EARLY SIGNS OF ANTICYLONIC FLOW DEVELOPING OVER THE AREA BY LATE
SUNDAY. COMPARATIVELY THE GFS MAINTAINS NORTHWEST FLOW OVR THE AREA
AS A RESULT OF A STRONGER TROUGH OVER WRN CANADA. THE GEM/UKMET
SOLUTIONS OVER A REASONABLE COMPROMISE BETWEEN THE GFS/ECMWF. IN ANY
CASE...EXPECT CONDITIONS TO REMAIN DRY WITH TEMPERATURES MODERATING
BACK INTO THE 50S AND 60S FOR THE SUNDAY THROUGH TUESDAY TIMEFRAME.
&&
.AVIATION...12Z TAF ISSUANCE...
MAIN AVIATION CONCERN WILL BE THE FOG...SOME OF WHICH HAS BEEN
LOCALLY DENSE THAT HAS DEVELOPED ACROSS THE WESTERN NEBRASKA
AIRFIELDS THIS MORNING. THESE LOW CIGS WILL HANG ON UNTIL AROUND
15 OR 16Z BEFORE LIFTING. SE WYOMING TERMINALS WILL HAVE GUSTY
WINDS TO CONTEND WITH BY LATE THIS MORNING AND MORE SO DURING THE
AFTERNOON TIMEFRAME. EXPECT TO SEE THESE GUSTS APPROACH 30 OR 40
KNOTS THROUGH THIS PERIOD. SNOW WILL DEVELOP AT KRWL AFTER 03Z OR
SO...AS THE NEXT STORM SYSTEM BEGINS TO IMPACT THE REGION.
&&
.FIRE WEATHER...
A WINDY START TO THE DAY FOR AREAS WEST ALONG AND WEST OF THE
LARAMIE RANGE TODAY...AS GUSTS OF 40 TO 50 MPH HAVE BEEN COMMON.
THESE WINDS WILL CONTINUE THROUGH MUCH OF THE DAY BEFORE RELAXING
THIS EVENING AND OVERNIGHT. MEANWHILE...FOGGY CONDITIONS ACROSS THE
WESTERN PANHANDLE WILL PERSIST THROUGH MID/LATE MORNING BEFORE
LIFTING. ONE MORE WARM DAY IS IN STORE TODAY WITH HIGH TEMPERATURES
THAT WILL REACH THE 50S WEST OF THE LARAMIE RANGE AND 60S AND 70S
OUT ON THE EASTERN PLAINS. BIG CHANGES ARE ON THE WAY TOMORROW
HOWEVER...AS A COLD FRONT BEGINS TO PUSH THROUGH THE AREA.
PRECIPITATION WILL TRANSITION FROM RAIN TO SNOW THROUGH THE DAY AS
THE FRONT PROGRESSES SOUTH. PRECIPITATION WILL TURN TO ALL SNOW FOR
WEDNESDAY NIGHT AND THURSDAY. SIGNIFICANT ACCUMULATING SNOW IS
LOOKING INCREASINGLY POSSIBLE. MUCH COLDER AIR WILL FILTER IN FOR
THURSDAY AND FRIDAY AS WELL...WITH HIGHS ONLY CLIMBING INTO THE 20S
AND 30S.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 9 AM TUESDAY FOR WYZ104-WYZ105-WYZ106-
WYZ109-WYZ110.
WINTER STORM WATCH FROM 6 AM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ103-WYZ105-WYZ110-WYZ112-WYZ114.
WINTER STORM WATCH FROM 6 PM WEDNESDAY TO 6 PM THURSDAY FOR
WYZ106-WYZ115-WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM/AVIATION/FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
228 AM EDT THU OCT 25 2012
.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
FRIDAY. TROPICAL SYSTEM SANDY IS FORECAST TO MOVE NORTHWARD AND
REMAIN OFF THE SOUTHEAST COAST THIS WEEKEND. SEE THE LATEST
ADVISORY FROM THE NATIONAL HURRICANE CENTER. A COLD FRONT
APPROACHING FROM THE WEST WILL MOVE THOUGH THE AREA SUNDAY. THE
COOLEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LOW-LEVEL MOISTURE HAS INCREASED IN THE EASTERLY FLOW SOUTH OF THE
PRESSURE RIDGE. THIS MOISTURE COMBINED WITH STRONG RADIATIONAL
COOLING HAS RESULTED IN AREAS OF FOG. THE FOG MAY BECOME DENSE AND
A DENSE FOG ADVISORY MAY BE NEEDED ESPECIALLY IN THE EAST PART
WHERE DEW POINT TEMPERATURE ARE HIGHER. HEATING AND MIXING SHOULD
HELP DISSIPATE THE FOG BY 1000 AM. THE TEMPERATURE GUIDANCE IS
CLOSE. EXPECT HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
SURFACE HIGH PRESSURE WILL REMAIN ENTRENCHED OVER THE REGION
THROUGH THURSDAY NIGHT. THE RIDGE WILL WEAKEN FRIDAY AHEAD OF THE
COLD FRONT APPROACHING FROM THE WEST AND TROPICAL SYSTEM SANDY
PUSHING NORTHWARD OFF THE SOUTHEAST COAST. MOISTURE SHOULD REMAIN
SHALLOW THROUGH FRIDAY. MOISTURE MAY BECOME DEEP ENOUGH TO SUPPORT
SHOWERS FRIDAY NIGHT IN THE EASTERLY FLOW BETWEEN SANDY OFF THE
SOUTHEAST COAST AND THE PRESSURE RIDGE TO THE NORTH. THE GFS IS
MORE PRONOUNCED WITH THIS MOISTURE COMPARED TO THE NAM. FORECASTED
CHANCE POPS IN THE EAST PART. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE MODELS SHOW TROPICAL CYCLONE SANDY MOVING
NORTHWARD AHEAD OF THE UPPER-LEVEL TROUGH MOVING INTO THE EASTERN
PART OF THE NATION. THE ECMWF HAS BEEN PERSISTENT IN ITS PATH
WHICH IS MORE WEST THAN THE OTHER MODELS BUT STILL KEEPS THE
CENTER WELL EAST OF THE FORECAST AREA.
THE COLD FRONT APPROACHING THE FORECAST AREA WILL BECOME DIFFUSE
BECAUSE OF THE NORTHERLY FLOW ASSOCIATED WITH THE CIRCULATION OF
SANDY. THE LACK OF CONVERGENCE INTO THE FRONT PLUS THE MODEL
FORECAST OF DEEPER MOISTURE ASSOCIATED WITH SANDY STAYING EAST OF
THE AREA SUPPORTS JUST LOW POPS. BREEZY NORTHERLY WINDS ARE
EXPECTED SATURDAY...ESPECIALLY ACROSS THE EASTERN MIDLANDS. THE
COOLEST AIR OF THE SEASON SO FAR WILL CIRCULATE INTO THE AREA
BEHIND THE COLD FRONT FOR EARLY NEXT WEEK. THE GFS ENSEMBLE MEANS
SUPPORT LOWS IN THE MIDDLE AND UPPER 30S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR SURFACE MOISTURE HAS CONTINUED TO INCREASE WITH DEWPOINTS IN
THE MID TO UPPER 50S. PATCHY FOG ALREADY DEVELOPING AGS/OGB WITH
IFR VSBYS. HI-RES HRRR AND SREF INDICATE REDUCED VSBYS SO HIGHER
THAN NORMAL CONFIDENCE IN RESTRICTIONS AT TERMINALS THROUGH THE
PREDAWN HOURS. IFR VSBYS TO DROP TO LIFR AFTER 08Z-09Z OGB/AGS
WHILE CAE/CUB START VFR AND DROP TO IFR AFTER 10Z WITH POSSIBLE
LIFR VSBYS AT TIMES BUT LOWER CONFIDENCE IN LIFR AT THIS TIME.
FOG SHOULD DISPERSE AFTER 15Z AS NORTHEAST-EASTERLY WINDS PICK UP
TO AROUND 10 MPH AND MIXING TAKES PLACE. SOME AFTERNOON CUMULUS
BUT NO RESTRICTIONS TO CIGS.
EXTENDED AVIATION OUTLOOK...INCREASING CONFIDENCE IN RESTRICTIONS
FRIDAY MORNING IN FOG AND STRATUS. INCREASING WINDS AND GUSTS
EXPECTED THIS WEEKEND ASSOCIATED WITH INCREASED PRESSURE GRADIENT
AS SANDY LIFTS NORTHWARD IN THE ATLANTIC.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 AM EDT THU OCT 25 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 416 PM EDT WED OCT 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALF OVER
THE PLAINS BTWN DEEP TROF OFF THE PACIFIC COAST AND AN UPR RDG AXIS
ALIGNED FM HUDSON BAY THRU THE CENTRAL GRT LKS INTO THE SE CONUS.
DESPITE THE PRESENCE OF AN UNSEASONABLY WARM...MOIST LLVL AIRMASS
/PWATS UP TO 250 PCT OF NORMAL/ OVER THE UPR GRT LKS...THERE ARE
ONLY A FEW -SHRA NOTED ON THE MQT RADAR DUE TO STRONG CAPPING INVRN
BTWN H75-8 AS NOTED ON THE LOCAL 12Z RAOBS EVEN THOUGH A SHALLOW...
WEAK COLD FNT ATTENDANT TO CLOSED LO OVER SASKATCHEWAN HAS LIMPED
INTO THE FAR WRN CWA. A DISTURBANCE WITH 70KT H5 WINDS LIFTING NEWD
THRU THE DAKOTAS IS CAUSING AN AREA OF -SHRA UNDER SHARP H7 TEMP
GRADIENT OVER THE NRN PLAINS INTO NW MN WELL WELL W OF THE SFC COLD
FNT AND THE AREA INFLUENCED BY THE SHARP MID LVL CAP. THE SHRTWV IN
THE NRN PLAINS AND ANOTHER MORE VIGOROUS DISTURBANCE MOVING THRU THE
CNTRL ROCKIES HAVE CONSPIRED TO CAUSE A LO PRES TO DVLP FARTHER S ON
THE COLD FNT IN KANSAS. OVER UPR MI... AREAS OF FOG LINGER
ESPECIALLY OVER THE CENTRAL ZNS WHERE LLVL SSE FLOW IS UPSLOPING.
THE LOWERING SUN ANGLE AND PERSISTENT FOG AND LO CLDS HAVE LIMITED
SFC WARMING. FARTHER TO THE S...MORE BREAKS IN THE LO CLDS HAVE
ALLOWED FOR MORE SFC WARMING OVER ERN IOWA AND SRN WI.
TNGT...MAIN FCST CONCERNS ARE SHRA/TS CHCS AND POTENTIAL FOR SVR WX
AS DISTURBANCES LIFT TO THE NE OUT OF MEAN WRN TROF. SPC HAS PLACED
WRN UPR MI IN A SLGT RISK FOR SVR STORMS TNGT. GIVEN ABSENCE OF ANY
SGNFT SFC WARMING OVER UPR MI THIS AFTN AND SHARP INVRN...ANY
CONVECTION SHUD BE ELEVATED AND DEPENDENT ON WHETHER/HOW QUICKLY THE
SHARP H8-75 INVRN WEAKENS. 12Z GFS/NAM HAVE TRENDED TO SHIFT FOCUS
FOR MOST SGNFT DEEP LYR QVECTOR CNVGC ASSOCIATED WITH DISTURBANCE
NOW IN THE NRN PLAINS INTO MN AT 00Z...A LOGICAL SHIFT GIVEN HI
AMPLITUDE PATTERN IN PLACE AND SHIFT OF SECOND SHRTWV FARTHER W INTO
THE UPR TROF AXIS. HIER RES NAM RUN SHOWS THE SHARPEST/SLOPED H85-7
FGEN/UVV IMPACTING WRN LK SUP AT 00Z BEFORE SHIFTING TO THE NE AS
THE DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE FIRST SHRTWV FADES AS
THE UPR TROF DEEPENS FARTHER W WITH CLOSER APRCH OF 2ND SHRTWV.
GIVEN THE STRENTH OF THE CAPPING ILLUSTRATED BY THE 12Z RAOBS...
SUSPECT MOST WDSPRD AND INTENSE SHRA/TS THIS EVNG WL MISS THE LAND
CWA TO THE W...WITH ALL BUT THE FAR W SEEING NOTHING MORE THAN
ISOLD-SCT -SHRA/TS OR -DZ IN THIS SCENARIO AS WEAKER FORCING HERE
LIMITS THE WEAKENING OF THE CAP. EVEN THE NAM DOES SHOW A SECOND
AREA OF HIER QPF OVER THE SE ZNS...AND THIS MIGHT DEPEND ON IF SOME
SHRA DVLP WITH THE CLRG OVER SE WI AND MOVE TO THE N. ALTHOUGH THE
GFS SHOWS SIMILAR UPR FORCING...THIS MODEL...WITH THE SUPPORT OF THE
12Z CNDN GEM MODEL...SHOWS AXIS OF HIER QPF OVER WRN UPR MI NEAR THE
SFC COLD FNT. GIVEN THE PLACEMENT OF THE SHARPER DYNAMICS AND
PATTERN RECOGNITION... THINK THE NAM FCST IS THE BEST BET. GIVEN
IMPRESSIVE DEEP LYR SHEAR ABV THE MORE STABLE LYR NEAR THE SFC...ANY
TS THAT MIGHT IMPACT THE WRN ZNS COULD TURN SVR WITH HAIL THE MAIN
THREAT GIVEN SFC BASED STABILITY. WITH THE UNSEASONABLY WARM...MOIST
AIRMASS IN PLACE AND HI FRZG LVL...ANY SHRA COULD DUMP HEAVY RA EVEN
IF THEY ARE FAST MOVING UNDER THE STEADY FLOW ALF. AS THE SECOND
SHRTWV RIDES NEWD LATER TNGT...ANOTHER AREA OF VIGOROUS H85-5
QVECTOR CNVGC/UPR DVGC IS PROGGED TO IMPACT MAINLY MN TOWARD 12Z. SO
AFT INITIAL ROUND OF HIER POPS LIFTS TO THE NE...SUSPECT ANOTHER
ROUND OF HEAVIER SHRA/SOME TS WL INVADE THE WRN CWA LATER. WITH ONLY
MODEST DIURNAL COOLING...EXPECT FOG TO REDVLP... ESPECIALLY IN AREAS
OVER THE ECNTRL EXPERIENCING UPSLOPE SSE WINDS.
THU...AS DISTURBANCE/ACCOMPANYING H3 JET MAX AND DEEP LYR QVECTOR
CNVGC/UPR DVGC RIDE TO THE NNE WITH ASSOCIATED SFC LO MOVING UP THE
STALLED COLD FNT OVER THE W...EXPECT AN AREA OF SHRA/EMBEDDED TS TO
IMPACT MAINLY THE W HALF IN THE MRNG BEFORE THE SHRTWV MOVES FAR
ENUF TO THE N AND DEEP LYR QVECTOR DVGC DVLPS WITH DNVA/STRONG CAD
IN THE WAKE OF COLD FROPA AS SFC LO MOVES INTO ONTARIO IN THE AFTN.
THINK CATEGORICAL POPS ARE APPROPRIATE OVER THE W IN THE MRNG...WITH
THE HIER POPS FOLLOWING THE COLD FROPA TO THE E. ALTHOUGH SFC BASED
STABILITY WL LIMIT THE INCRS IN WIND SPEED BLO ADVY LVL...S WINDS
NEAR LK MI MAY BECOME QUITE GUSTY IN ADVANCE OF THE COLD FROPA UNDER
H925 WINDS UP TO 50 KTS AND WITH SHARP PRES FALL CENTER MOVING INTO
ONTARIO AHEAD OF THE SFC LO PROVIDING ENHANCEMENT TO THE S GRADIENT
FLOW. COMBINATION OF STRONG CAD AND W H925 WINDS INCRSG UP TO 35-40
KT IN THE WAKE OF THE FROPA MIGHT CAUSE WIND GUSTS OVER THE EXPOSED
KEWEENAW TO AT LEAST APRCH ADVY LVL IN THE AFTN. ENUF COLD AIR MAY
ARRIVE TO AT LEAST MIX LINGERING USPLOPE LK ENHANCED -SHRA WITH SN
OVER THE FAR W IF THE COLDER NAM SHOWING H85 TEMPS FALLING TOWARD
-5C AT 00Z FRI VERIFIES. THE SHARP COLD FROPA WARRANTS A NON DIURNAL
TEMP TREND...WITH TEMPS FALLING BEHIND THE FROPA ESPECIALLY OVER THE
W.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 PM EDT WED OCT 24 2012
BY EARLY THURSDAY EVENING...THE MAIN SFC LOW SHOULD BE OVER NE
ONTARIO...WITH THE COLD FRONT JUST E OF UPPER MI...AND A SECONDARY
TROUGH SET UP E-W FROM THE LOW ACROSS LAKE WINNIPEG. THE 500MB LOW
OVER LAKE WINNIPEG WILL SLIDE NNE OUT OF THE AREA.
W FLOW AND 850MB TEMPS AROUND -8C SHOULD HELP KEEP SOME LAKE
ENHANCED SHOWER ACTIVITY GOING ACROSS W UPPER MI. HOWEVER...THE LOW
LEVEL MOISTURE WILL BE QUITE A BIT LESS DURING THAT TIME...WITH
PLENTY OF CLOUDS BUT JUST LIGHT SNOW SHOWERS OR FLURRIES POSSIBLE.
EXPECT THE SECONDARY TROUGH TO PUSH ACROSS THE KEWEENAW PENINSULA
FRIDAY EVENING...BUT HAVE LITTLE WITH IT AS MUCH OF THE ENERGY
REMAINS CLOSER TO THE SFC LOW ITSELT OVER N HUDSON BAY BY THAT TIME.
ANOTHER ROUND OF CLOUDS AND LIGHT SNOW SHOWERS. NO SIGNIFICANT
ACCUMULATION IS EXPECTED...AS THE BEST SNOW GROWTH REGION /AOA
800MB/ REMAINS WELL ABOVE THE MOISTURE.
THE LARGE SCALE TROUGH WILL DOMINATE MUCH OF THE NATION FRIDAY NIGHT
THROUGH AT LEAST SATURDAY. AN ELONGATED AREA OF HIGH PRESSURE
STRETCHING FROM THE MAIN HIGH OVER CENTRAL CANADA TO THE CENTRAL
PLAINS FRIDAY NIGHT WILL SLOWLY BUILD ACROSS THE UPPER GREAT
LAKES...THROUGH AT LEAST SUNDAY.
HIGH PRESSURE WILL REMAIN STRONG OVER ONTARIO THROUGH THE MID MS
VALLEY...EVEN AS THE STRONG SYSTEM PUSHES TOWARDS THE EAST COAST. AS
A RESULT OF THE NEARING STORM SYSTEM...THE SFC HIGH SHOULD MAINTAIN
ITS INFLUENCE OVER THE W HALF OF UPPER MI. HOWEVER...N FLOW WILL
LIKELY DOMINATE FAR E UPPER MI FROM SUNDAY NIGHT THROUGH THE END OF
THE FCST PERIOD /WEDNESDAY/ AS THE LOW RETROGRADES .
UNLIKE THE ECMWF WHICH CONTINUES TO SHOW GOOD RUN TO RUN CONSISTANCY
ON THE POTENTIAL STORM SYSTEM SLIDING TOWARDS THE E COAST...THE GFS
IS A BIT MORE JUMPY. THE MODEL IS SPLIT ON WHETHER TO BRING THE LOW
OFF TO SEE...OR EVEM MORE ONSHORE BY WEDNESDAY MORNING /NEAR LAKE
HURON/ IF THE 24/06Z RUN IS CORRECT. THE 24/12Z GFS SHIFTED THE
500MB LOW APPROX 300-350MI W OF ITS PREVIOUS MORE OUT TO SEA
LOCATION MONDAY MORNING. WILL CONTINUE TO HEDGE THE FCST A BIT
CLOSER TO THE MORE STABLE ECMWF SOLUTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 138 AM EDT THU OCT 25 2012
QUITE A PESSIMISTIC FORECAST IN THE MAKING AS ABUNDANT MOISTURE AND
AN OVERALL STAGNANT AIRMASS ALONG A SURFACE BOUNDARY WILL KEEP CIGS
AND VIS QUITE LOW AT ALL SITES THROUGH MUCH OF THE TAF PERIOD.
GIVEN GENERAL FLOW FROM THE N...HAVE KEPT CIGS IN THE VLIFR/LIFR
RANGE OVERNIGHT. DO NOT EXPECT MUCH IMPROVEMENT AT IWD WITH FLOW OUT
OF THE NORTH TO NE THROUGH EARLY THURSDAY MORNING. DRIER AIR WILL
MOVE IN BY LATE AFTERNOON AND EVENING WHICH SHOULD BRING IMPROVING
CONDITIONS INTO THE MVFR RANGE.
A PERIOD OF MVFR CIGS VSBY FOLLOWING AN ARES OF SHRA/TSRA MAY LOWER
AGAIN INTO THE IFR RANGE WITH ABUNDANT LOW LEVEL MOISTURE REMAINING
OVER THE AREA. A STRONG COLD FRONT SHOULD REACH CMX BY 18Z
THURSDAY...WITH A QUICK WIND SHIFT TO THE WNW AND WIND SPEED
INCREASE TO AROUND 20KT.
SSE UPSLOPE FLOW AT SAW HAD REMAINED BELOW LANDING MINS MOST OF THIS
EVENING BUT HAVE LIFTED SLIGHTLY AFTER SOME LIGHT RAIN MOVED
THROUGH. EXPECT THAT THE FOG AND LOW CIGS WILL CONTINUE UNTIL MORE
PERSISTENT RAIN MOVES IN LATE TONIGHT AND THU WHEN WINDS SHIFT MORE
TO THE SSW AND REDUCE UPSLOPE FLOW AHEAD OF THE APPROACHING COLD
FRONT. LASTLY...MARGINAL LLWS OF ABOUT 30-40KTS OVER THE LOWEST
1.5KFT IS POSSIBLE AS WINDS ALOFT INCREASE AHEAD OF THE FRONT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EDT WED OCT 24 2012
EXPECT DENSE FOG OVER THE W HALF OF LAKE SUPERIOR TO LINGER THRU
THIS EVENING BEFORE THE ARRIVAL OF SOMEWHAT DRIER LOW LEVEL AIR IS
ABLE TO DISSIPATE THE FOG. THE DENSER FOG WILL LINGER LONGEST NEAR
THE W SHORE OF UPPER MI. OTHERWISE...EXPECT S WINDS TO INCREASE TO
30 KTS OVER THE E HALF OF THE LAKE ON THU AS A STRONG COLD FRONT
APPROACHES. RELATIVELY LIGHT WINDS OVER THE W AND CENTRAL WILL SHIFT
TO THE W FOLLOWING THE COLD FROPA ON THU AND INCREASE UP TO 30 KTS
IN THE AFTERNOON...WITH HIGH PRESSURE DEVELOPING OVER THE NORTHERN
AND CENTRAL PLAINS. THERE MAY BE SOME GALE FORCE WINDS NEAR THE KEWEENAW
LATE IN THE DAY. THESE MARGINAL GALES WILL LIKELY IMPACT PORTIONS OF
THE CENTRAL LAKE ON THU EVENING...SO HOISTED A GALE WATCH FOR NOW IN
THIS AREA. LIGHTER WINDS WITH HIGH PRESSURE WILL SLOWLY PUSH OVER
THE UPPER GREAT LAKES THROUGH MONDAY...WITH THE STRONGEST WINDS OVER
E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
348 AM CDT THU OCT 25 2012
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
THUNDERSTORMS HAVE DEVELOPED...BUT REMAIN PRIMARILY ALONG AND
AHEAD OF THE FRONT FROM NRN IA TO SWRN WI. A FEW MORE HAVE ALSO
FORMED NEAR THE TWIN CITIES AND NEW RICHMOND...BUT SHOULD NOT
PERSIST IN THOSE LOCATIONS FOR TOO LONG. THESE STORMS WILL
CONTINUE ON A SCATTERED BASIS FOR MUCH OF THE OVERNIGHT HOURS AND
AFFECT MAINLY EAU. FARTHER WEST...EXPECT WIDESPREAD RAIN TO DEVELOP
FROM SOUTHWEST TO NORTHEAST DURING THE OVERNIGHT HOURS AS AN
IMPULSE OVER THE PLAINS PUSHES NORTHEAST. STILL EXPECTING THE RAIN
TO TURN TO SNOW AT AXN...RWF...AND STC BETWEEN 09Z-12Z AS COLDER
AIR PUSHES SOUTHEAST. SOME SNOW MAY MIX WITH RAIN TOWARD LATE
MORNING AT MSP...EARLY AFTERNOON AT RNH...AND MID AFTERNOON NEAR
EAU. OTHERWISE...CONDITIONS WILL DETERIORATE TO IFR OR LIFR
CONDITIONS WITH THE RAIN AND SNOW BEFORE IMPROVING MARKEDLY BY
THURSDAY EVENING.
KMSP...A FEW STORMS HAVE FORMED SOUTHEAST OF THE TERMINAL...BUT
CONFIDENCE IS NOT HIGH ENOUGH WITH REGARDS TO PROXIMITY TO
INCLUDE THEM AS A VCTS IN THE TAF ATTM. STEADY RAIN WILL DEVELOP
LATE TONIGHT WITH IFR CONDITIONS PERSISTING THROUGH LATE
MORNING...THEN GRADUALLY IMPROVE THROUGH THE DAY AS DRIER AIR
MOVES IN. COULD SEE A FEW SNOWFLAKES MIX WITH THE RAIN BY EARLY
AFTERNOON.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS WNW 10G20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...VFR. SLIGHT CHANCE -RASH. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/BORGHOFF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1207 AM CDT Thu Oct 25 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today through Saturday...
In the short term, the primary focus will be precipitation chances
with a dynamic cold front approaching from the northwest. Although
most model solutions continue to indicate light, warm sector
precipitation across northwest Missouri this afternoon and evening,
and low level moisture is evident in the scattered to broken MVFR
deck, the weak forcing resulting from slight isentropic lift has not
been enough to produce rain showers ahead of the surface cold front.
Short range hi-res models have caught onto the lack of precipitation
this afternoon, and keep rainfall out of Missouri prior to 06z. Have
hedged a bit earlier than the latest HRRR forecasts in bringing a
chance of precipitation into far northwestern portions of the CWA
for the potential that storms could develop on the boundary and move
into the far northwest before 06z; however, the better chances for
showers and thunderstorms will be Thursday as the main trough axis
dips into southeast Nebraska and begins driving the surface front
more quickly to the southeast.
Both the NAM and GFS produce convective precipitation along the low
level boundary tonight as frontogenesis increases and midlevel
cooling supports temporarily higher lapse rates, mainly above 925mb.
The best chance for any robust storms to develop will likely be
confined to the period between 06z-09z when storms can be rooted
more closely to the surface; afterward, the low-level inversion will
be compounded by surface frontal passage, and the focus for
precipitation will shift a bit closer to the 850mb front. Most
precipitation during the daylight hours on Thursday should occur
mainly along the 850 front, with a small chance for some isolated
development along the surface front in far eastern portions of the
forecast area early Thursday afternoon. Rain chances will linger a
bit across the southeast as midlevel forcing broadens early Friday
evening, with any remaining showers expected to move out shortly
between 00z-06z Friday.
Temperatures will drop significantly behind the cold front, and in
general, highs will be reached just prior to frontal passage on
Thursday. Highs for Friday and Saturday will be well below average
as cold surface high pressure settles into the region, and lows
Friday night could drop a few degrees below freezing across areas
that have not previously received a hard freeze.
Laflin
Medium Range (Saturday Night through Wednesday)...
As the Canadian surface ridge remains settled over the area this
weekend...temperatures will dip to around 30 degrees Sunday morning.
The northern zones have experienced a hard freeze so will have to
make some decisions tomorrow about headlines for the southern three
quarters of the area for Sunday and possibly Monday mornings. The
500-1000mb thicknesses are around 537-540DM by Sunday morning with
very light winds and clear skies.
Lows on Monday morning may be a few degrees warmer as the surface
ridge slides further east. Not much in the way of advection at this
time though and the dry conditions with light winds...may require a
downward tweak of the lows for Monday morning. By Tuesday...we will
see the winds finally swing around to the south as the ridge moves
further east so there will be an increase in the thicknesses and 850
mb temps...therefore we should see above freezing temperatures on
Tuesday and Wednesday mornings.
Daytime highs through the extended will show a gradual warming trend
as well from the 40s on Sunday to the around 60 degrees F by Tuesday
and Wednesday.
Storm track remains well to the north so no precipitation is
expected through the period. Adolphson
&&
.AVIATION...
For the 06Z TAFs...strong cold front over southeast Nebraska and far
northwest MO will make very little southward push until later
tonight, and may not clear STJ until 10Z despite being just a few
miles away. Front will then accelerate through the remainder of
western and central MO through Thursday morning. Widespread IFR cigs
behind the front are likely to overspread all terminals through the
morning, and may be slow to lift and scatter through the afternoon.
Post-frontal convection is currently organizing and growing
widespread over KS/NE, but is forecast to weaken and decrease in
coverage by the time it reaches the KC terminals. Will therefore
continue to include only a VCTS for now, and will watch for
amendments to add thunder as needed.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1148 PM CDT WED OCT 24 2012
.DISCUSSION...LATEST FOG/STRATUS IMAGERY LOOP ALONG WITH SURFACE
OBSERVATIONS SHOW A SWATH OF STRATUS ACROSS NORTHERN NORTH DAKOTA.
THE RUC 925MB RH FIELD SEEMED TO HAVE THIS HANDLED WELL...MOVING
THIS AREA SOUTHEAST OVERNIGHT. CONCUR WITH THIS...ESPECIALLY AS
THE UPPER TROUGH/MAXIMUM CYCLONIC CURVATURE NOW CENTERED IN THE
WEST MOVES INTO CENTRAL NORTH DAKOTA BY 12Z THURSDAY. FOR THE REST
OF TONIGHT...DUE TO WIDESPREAD STRATUS HAVE WARMED MINIMUM TEMPERATURES
INTO THE UPPER 20S IN THE FAR WEST AND MID 20S SOUTHWEST. ALSO WITH
UPSTREAM CANADIAN SURFACE OBS SHOWING FLURRIES...HAVE ADDED THAT INTO
THE NORTH CENTRAL OVERNIGHT.
A COLD H85 POCKET OF AIR AS DENOTED BY THE -8C IN SOUTHERN
SASKATCHEWAN AND EASTERN MONTANA WILL GRADUALLY SHIFT SOUTHEAST
LATER TONIGHT INTO EARLY THURSDAY. THIS WILL PROMOTE MORE INSTABILITY
THURSDAY WITH POSSIBLE FLURRIES IN THE NORTH. WILL MAINTAIN THIS
IN THE FORECAST. OTHERWISE DRY AND COLD ELSEWHERE.
&&
.AVIATION...LOW PRESSURE ACROSS MANITOBA WILL MOVE EAST AND MAINTAIN
A COOL/BRISK TO WINDY NORTHWEST FLOW THROUGH THURSDAY. WIDESPREAD
MVFR CIGS ACROSS THE NORTHERN AERODROMES WILL CONTINUE TO MOVE
SOUTH THROUGH 12Z THURSDAY. EXPECT A GRADUAL LIFTING AND DETERIORATION
OF THE MVFR CIGS THURSDAY MORNING INTO THE EARLY AFTERNOON. NORTHWEST
WINDS WILL INCREASE WITH SUSTAINED WINDS BETWEEN 20 AND 25 MPH...AND
GUSTS TO 35 MPH THURSDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1052 PM PDT Wed Oct 24 2012
.SYNOPSIS...A band of rain and mountain snow will move through the
area today and tonight. The weather will generally be quiet on
Thursday before the next weather system arrives Friday with
additional storms for the weekend. More precipitation is expected
into early next week.
&&
.DISCUSSION...
Update to account for expiration of snow advisory in the
East Slopes. Western edge of the deformation band is weakening
with cloud tops quickly warming and HRRR all in good agreement
that additional QPF amounts will be 0.02" or less. As such, we
will allow the advisory to run its course and expire at 11PM.
Still be aware of slick driving conditions during the morning
hours due to re-freezing and/or any isolated light snow
accumulations from convective snow showers moving through
overnight.
Previous discussion: We have made some slight adjustments to
the winter weather advisory for the remainder of the night. A
band of light to moderate precipitation continues to impact the
northern mountains from the Pasayten Wilderness...eastward to the
Sandpoint, ID. Satellite reveals warming cloud tops suggesting
this band is weakening and is most concentrated over the Okanogan
Highlands...NE WA Mtns...and Nrn ID Panhandle.
A tour of observation networks across the region suggest snow levels
have dropped some with levels across the Okanogan Highlands, NE WA
Mtns, and Nrn ID Panhandle sitting around 3K ft. As such, we have
made adjustments to the winter wx advisory to bring light
acccumulations down to these levels. In IDZ004, the Central
Panhandle Mtns, pcpn is struggling to materialize and this will
equate to the lower snow totals. The NAM...EC...and HRRR have
captured this better then the GFS and were referenced for the
remainder of the night. Despite the lack of pcpn over this region
from the stable deformation band, cellular cloud structure in
conjuction with the model 500mb temperatures suggest the
atmosphere is going to become increasingly unstable once again.
Winds behind this evening`s wave should become SW/W before
swinging to the W/NW Thursday morning. In addition, another
midlevel circulation is currently crossing the Blue Mtns and
should incr the shower activity across lower Shoshone County
overnight. All it will take is a few heavy convective showers to
get going and localized accumulations of 1-3 inches will be
possible with the convective showers.
On another note, the lack of pcpn has allowed pockets of cooler
temperatures across the Idaho Panhandle with Wallace currently
sitting at 35F with a 32F dewpoint. Bonners Ferry is also 36F over
32F and as pcpn reaches into these locations, I would not be
surprised to see snow reach these valley floors. If the pcpn
remains light, the above freezing temperatures should neglect any
impacts but if any heavier showers were to come through, light
accumulations will be possible on roadways including I-90
between Wallace and 4th of July Pass.
All things considered, we have lowered the snow advisory for the
Central Panhandle Mtns down to 2500 feet. If the 00z GFS was to
verify...1-3 inches of snow will be easily achievable in locations
like Deary, Wallace, and Lookout Pass which has come in with
0.25" liquid along a elongated convergence zone or pressure
trough at the surface. /sb
&&
.AVIATION...
06Z TAFS: The steady band of rain and snow has pushed north of all
terminals however steepening lapse rates and smaller midlevel
disturbances will keep a threat for showers of rain and snow in the
fcst through early Thursday. Meanwhile, the BL remains very moist
with widespread stratus and fog expected throughout the Columbia
Basin...West Plains...and L-C Valley. All VIS/CIG restrictions
associated with low clouds and fog should lift btwn 18-21z and weak
high pressure aloft should promote a relative quiet wx day across
the Inland NW. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 34 41 32 45 / 50 20 10 50 40 40
Coeur d`Alene 31 43 33 41 32 44 / 60 50 10 50 40 40
Pullman 29 41 32 40 33 48 / 40 40 10 60 40 40
Lewiston 34 47 35 45 37 52 / 50 30 10 60 30 30
Colville 33 45 29 44 31 47 / 70 50 10 50 40 40
Sandpoint 30 41 30 41 32 44 / 80 60 10 40 40 50
Kellogg 32 38 26 38 31 43 / 80 60 20 50 60 50
Moses Lake 28 47 34 45 33 49 / 10 10 10 40 20 30
Wenatchee 31 47 35 44 35 47 / 20 10 10 40 20 30
Omak 31 46 33 46 34 48 / 50 10 10 50 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT Thursday for Northern
Panhandle.
Winter Weather Advisory until 11 AM PDT Thursday for Central
Panhandle Mountains.
WA...Winter Weather Advisory until 11 AM PDT Thursday for Northeast
Mountains-Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for East
Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1015 PM PDT Wed Oct 24 2012
.SYNOPSIS...A band of rain and mountain snow will move through the
area today and tonight. The weather will generally be quiet on
Thursday before the next weather system arrives Friday with
additional storms for the weekend. More precipitation is expected
into early next week.
&&
.DISCUSSION...
We have made some slight adjustments to the winter weather
advisory for the remainder of the night. A band of light to moderate
precipitation continues to impact the northern mountains from the
Pasayten Wilderness...eastward to the Sandpoint, ID. A tour of
observation networks across the region suggest snow levels have
dropped some with levels across the Okanogan Highlands, NE WA
Mtns, and Nrn ID Panhandle sitting around 3K ft. As such, we have
made adjustments to the winter wx advisory to bring light
acccumulations down to these levels. In IDZ004, the Central
Panhandle Mtns, pcpn is struggling to materialize and this will
equate to the lower snow totals. The NAM...EC...and HRRR have
captured this better then the GFS and were referenced for the
remainder of the night. Despite the lack of pcpn over this region
from the stable deformation band, cellular cloud structure in
conjuction with the model 500mb temperatures suggest the
atmosphere is going to become increasingly unstable once again.
Winds behind this evening`s wave should become SW/W before
swinging to the W/NW Thursday morning. In addition, another
midlevel circulation is currently crossing the Blue Mtns and
should incr the shower activity across lower Shoshone County
overnight. All it will take is a few heavy convective showers to
get going and localized accumulations of 1-3 inches will be
possible with the convective showers.
On another note, the lack of pcpn has allowed pockets of cooler
temperatures across the Idaho Panhandle with Wallace currently
sitting at 35F with a 32F dewpoint. Bonners Ferry is also 36F over
32F and as pcpn reaches into these locations, I would not be
surprised to see snow reach these valley floors. If the pcpn
remains light, the above freezing temperatures should neglect any
impacts but if any heavier showers were to come through, light
accumulations will be possible on roadways and we will likely
handle any updates with short term forecasts based on the isolated
nature.
All things considered, we have lowered the snow advisory for the
Central Panhandle Mtns down to 2500 based on latest observations
and if the 00z GFS was to verify...1-3 inches of snow will be
easily achievable in locations like Deary, Wallace, and Lookout Pass.
The threat for steady snow has ended for the East Slopes of the
Cascades. Isolated to scattered showers will continue. Some
locations may receive the first burst of snow accumulation so far
this fall as showers become increasingly convective and
temperatures cool in between cloud shields. At the current hour, a
few heavier showers reside over southwestern Chelan county near
the Crest. Expect this unorganized activity to continue through
the night and extend into the Basin. AS such, we have included a
slight chance for showers for all locations through the remainder
of the night. /sb
&&
.AVIATION...
00Z TAFS: Another round of rain and mtn snow is currently moving
through the region and will continue to moisten an already juicy
boundary layer. Consequently, expect widespread mtn obscurations
along the northern mtns this evening and overnight. All terminals
are expected to lower to MVFR/IFR levels either with the onset of
pcpn or after the rain ends and skies briefly clear. Confidence on
a whole is low for all sites given a wide array of MOS solutions
per each TAF site. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 34 41 32 45 / 50 20 10 50 40 40
Coeur d`Alene 31 43 33 41 32 44 / 80 50 10 50 40 40
Pullman 29 41 32 40 33 48 / 50 40 10 60 40 40
Lewiston 34 47 35 45 37 52 / 80 30 10 60 30 30
Colville 33 45 29 44 31 47 / 100 50 10 50 40 40
Sandpoint 30 41 30 41 32 44 / 100 60 10 40 40 50
Kellogg 32 38 26 38 31 43 / 90 60 20 50 60 50
Moses Lake 28 47 34 45 33 49 / 0 10 10 40 20 30
Wenatchee 31 47 35 44 35 47 / 10 10 10 40 20 30
Omak 31 46 33 46 34 48 / 80 10 10 50 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT Thursday for Central
Panhandle Mountains.
Winter Weather Advisory until 11 AM PDT Thursday for Northern
Panhandle.
WA...Winter Weather Advisory until 11 AM PDT Thursday for Northeast
Mountains-Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for East
Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
612 AM EDT THU OCT 25 2012
.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
FRIDAY. TROPICAL SYSTEM SANDY IS FORECAST TO MOVE NORTHWARD AND
REMAIN OFF THE SOUTHEAST COAST THIS WEEKEND. SEE THE LATEST
ADVISORY FROM THE NATIONAL HURRICANE CENTER. A COLD FRONT
APPROACHING FROM THE WEST WILL MOVE THOUGH THE AREA SUNDAY. THE
COOLEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW-LEVEL MOISTURE HAS INCREASED IN THE EASTERLY FLOW SOUTH OF THE
PRESSURE RIDGE. THIS MOISTURE COMBINED WITH STRONG RADIATIONAL
COOLING HAS RESULTED IN AREAS OF FOG. THE FOG MAY BECOME DENSE AND
A DENSE FOG ADVISORY MAY BE NEEDED ESPECIALLY IN THE EAST PART
WHERE DEW POINT TEMPERATURE ARE HIGHER. HEATING AND MIXING SHOULD
HELP DISSIPATE THE FOG BY 1000 AM. THE TEMPERATURE GUIDANCE IS
CLOSE. EXPECT HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
SURFACE HIGH PRESSURE WILL REMAIN ENTRENCHED OVER THE REGION
THROUGH THURSDAY NIGHT. THE RIDGE WILL WEAKEN FRIDAY AHEAD OF THE
COLD FRONT APPROACHING FROM THE WEST AND TROPICAL SYSTEM SANDY
PUSHING NORTHWARD OFF THE SOUTHEAST COAST. MOISTURE SHOULD REMAIN
SHALLOW THROUGH FRIDAY. MOISTURE MAY BECOME DEEP ENOUGH TO SUPPORT
SHOWERS FRIDAY NIGHT IN THE EASTERLY FLOW BETWEEN SANDY OFF THE
SOUTHEAST COAST AND THE PRESSURE RIDGE TO THE NORTH. THE GFS IS
MORE PRONOUNCED WITH THIS MOISTURE COMPARED TO THE NAM. FORECASTED
CHANCE POPS IN THE EAST PART. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE MODELS SHOW TROPICAL CYCLONE SANDY MOVING
NORTHWARD AHEAD OF THE UPPER-LEVEL TROUGH MOVING INTO THE EASTERN
PART OF THE NATION. THE ECMWF HAS BEEN PERSISTENT IN ITS PATH
WHICH IS MORE WEST THAN THE OTHER MODELS BUT STILL KEEPS THE
CENTER WELL EAST OF THE FORECAST AREA.
THE COLD FRONT APPROACHING THE FORECAST AREA WILL BECOME DIFFUSE
BECAUSE OF THE NORTHERLY FLOW ASSOCIATED WITH THE CIRCULATION OF
SANDY. THE LACK OF CONVERGENCE INTO THE FRONT PLUS THE MODEL
FORECAST OF DEEPER MOISTURE ASSOCIATED WITH SANDY STAYING EAST OF
THE AREA SUPPORTS JUST LOW POPS. BREEZY NORTHERLY WINDS ARE
EXPECTED SATURDAY...ESPECIALLY ACROSS THE EASTERN MIDLANDS. THE
COOLEST AIR OF THE SEASON SO FAR WILL CIRCULATE INTO THE AREA
BEHIND THE COLD FRONT FOR EARLY NEXT WEEK. THE GFS ENSEMBLE MEANS
SUPPORT LOWS IN THE MIDDLE AND UPPER 30S.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
NEAR SURFACE MOISTURE HAS CONTINUED TO INCREASE WITH DEWPOINTS IN
THE MID TO UPPER 50S. PATCHY FOG ALREADY DEVELOPING AGS/OGB WITH
IFR VSBYS. HI-RES HRRR AND SREF INDICATE REDUCED VSBYS SO HIGHER
THAN NORMAL CONFIDENCE IN RESTRICTIONS AT TERMINALS THROUGH THE
PREDAWN HOURS. IFR VSBYS TO DROP TO LIFR AFTER 08Z-09Z OGB/AGS
WHILE CAE/CUB START VFR AND DROP TO IFR AFTER 10Z WITH POSSIBLE
LIFR VSBYS AT TIMES BUT LOWER CONFIDENCE IN LIFR AT THIS TIME.
FOG SHOULD DISPERSE AFTER 15Z AS NORTHEAST-EASTERLY WINDS PICK UP
TO AROUND 10 MPH AND MIXING TAKES PLACE. SOME AFTERNOON CUMULUS
BUT NO RESTRICTIONS TO CIGS.
EXTENDED AVIATION OUTLOOK...INCREASING CONFIDENCE IN RESTRICTIONS
FRIDAY MORNING IN FOG AND STRATUS. INCREASING WINDS AND GUSTS
EXPECTED THIS WEEKEND ASSOCIATED WITH INCREASED PRESSURE GRADIENT
AS SANDY LIFTS NORTHWARD IN THE ATLANTIC.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1132 AM EDT THU OCT 25 2012
.UPDATE...
ONLY TWEAK TO PREVIOUS GRIDS WAS TO ADJUST HOURLY TEMPERATURE
TRENDS MAINLY FOR THIS EVENING BASED ON UPSTREAM OBSERVATIONS IN
ASSOCIATION THE COLD FRONT PASSAGE. TRIED TO INCORPORATE A
NAM12/PREVIOUS FORECAST BLEND TO SHOW A BIT SHARPER OF A TEMP/DEW
POINT DROP OFF WITH FRONT. OTHERWISE...OTHER FORECAST ELEMENTS FOR
PERIOD ONE STILL APPEAR TO BE ON TRACK WITH HIGHS IN THE MID TO
UPPER 70S. HRRR HINTING AT SOME CONVECTIVE DEVELOPMENT ALONG THE
COLD FRONT ACROSS NORTHWEST INDIANA THIS EVENING...BUT STILL
SOMEWHAT SUSPICIOUS OF THIS SOLUTION WITH INSTABILITY EXPECTED TO
BE FAIRLY LIMITED UNTIL BECOMING MORE ELEVATED IN NATURE BEHIND THE
FRONT.
&&
.MARINE...
SOUTH WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH LATEST
MICHIGAN CITY OBSERVATIONS ALREADY INDICATING SOUTH GUSTS INTO
THE 25 TO 30 KNOT RANGE. CANNOT COMPLETELY RULE OUT A FEW GUSTS TO
NEAR GALES THIS AFTERNOON. OF GREATER CONCERN IS EARLY THIS
EVENING IN ASSOCIATION WITH THE FRONTAL PASSAGE. A NARROW BUT
STRONG CORRIDOR OF SURFACE PRESSURE RISES BEHIND THE FRONT SHOULD
INDUCE A PERIOD OF WEST GUSTS TO NEAR GALES THIS
EVENING...ESPECIALLY IN THE 00Z TO 04Z TIMEFRAME. HAVE HELD OFF ON
ANY UPGRADED HEADLINES AT THIS TIME...BUT WILL NEED TO CONSIDER AT
LEAST MENTION OF A FEW GUSTS TO GALE FORCE IN POSSIBLE NEARSHORE
FORECAST AMENDMENTS THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 703 AM EDT THU OCT 25 2012/
AVIATION.../12Z TAFS/
DVLPG SFC LOW ALONG STNRY FRONT OVER NE IA THIS MORNING WILL
DEEPEN/INTENSIFY AS IT LIFTS NE TODAY CAUSING STNRY FRONT TO SURGE
EASTWARD AS A CDFNT. STRONG SWLY WIND FIELD IN PLACE OVER THE AREA
ATTM WITH KIWX VWP INDICATING 40KT IN LOWEST GATE AT 2KFT. THESE
STRONG WINDS WILL MIX DOWN DURING THE DAY WITH SFC GUSTS 27-32KT
EXPECTED... HIGHEST AT SBN. OTRWS... VFR CONDITIONS THROUGH THE
DAY WITH JUST SCT CU.
CDFNT EXPECTED TO MOVE THROUGH SBN BY 04Z AND FWA BY 08Z FOLLOWED
BY A PERIOD OF SHOWERS WITH AVIATION CONDITIONS LOWERING AT LEAST
TO MVFR AND PSBLY IFR. INSTABILITY WILL BE LIMITED BUT PRBLY
SUFFICIENT FOR A FEW TSTMS AS FAR EAST AS NWRN INDIANA SO INCLUDED
VCTS IN SBN TAF. WNDSHFT ON CDFNT WILL BE ABRUPT FROM SW-NW WITH
STRONG LOW LEVEL CAA PROMOTING POST FRONTAL GUSTS THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 410 AM EDT THU OCT 25 2012/
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT...
THE FORECAST CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR A RECORD
HIGH TEMPERATURE AT SOUTH BEND TODAY AND THE TIMING OF A STRONG COLD
FRONT THURSDAY NIGHT ALONG WITH ASSOCIATED PRECIPITATION. HIGHS
WEDNESDAY WERE RATHER UNIFORM AROUND 78F DEGREES. ALTHOUGH A WARM
AND MOIST FLOW SHOULD CONTINUE FROM THE SOUTH AND SOUTHWEST TODAY...
SOMEWHAT COOLER AIR UNDER 925 MB SHOULD SPREAD INTO THE REGION IN
THE LOW LEVELS. HAVE KEPT HIGHS A LITTLE LOWER THAN YESTERDAY...
GENERALLY 75 TO 77 DEGREES...WHICH SHOULD KEEP THE TEMPERATURE BELOW
THE RECORD HIGH OF 80 DEGREES AT SOUTH BEND. A STRONG COLD FRONT WILL
MOVE ACROSS THE FORECAST AREA THURSDAY NIGHT. SOME QUESTION WHETHER
EARLY STORMS WILL BE SURFACE BASED...INCREASING THE RISK FOR SEVERE
STORMS WITH HIGH WINDS GIVEN MOMENTUM TRANSFER OF 50 TO 55 KNOTS IN
THE 925/850 MB LEVEL. HOWEVER..THE SUBSIDENCE INVERSION AND MID
LEVEL WARMING HAS INCREASED SIGNIFICANTLY UPSTREAM AS INDICATED ON
THE LINCOLN RAOB. CURRENT THINKING IS THAT ANY STORMS WILL BE
ELEVATED AND WILL BE POST FRONTAL...LIMITING GREATLY SEVERE WEATHER
POTENTIAL. GIVEN THE STRENGTH OF THE FRONT WHICH INCLUDES ABOUT A 25
DEGREE TEMPERATURE DROP IN THE FIRST 100 MILES...TEMPERATURES WILL
DROP TO BETWEEN 41F AND 43F OVER FAR SW AND WEST AREA. LASTLY...KEPT
LAKE EFFECT/LAKE ENHANCED SHOWERS OUT. WINDS VEER TOO FAR TO THE
NORTHEAST FRI NGT.
LONG TERM.../SAT-WED/
UPR LEVEL TROF OVER THE ROCKIES THIS MORNING WILL MOVE EAST TO THE
MS VALLEY AND DEEPEN A BIT BY SAT AS A SERIES OF MID LEVEL SHRTWVS
MOVE THROUGH THE BASE OF THE TROF. MODELS HAVE TRENDED A LITTLE
FASTER WITH SHRTWV EXPECTED TO MOVE THROUGH OUR AREA SAT... THUS
HAVE LOWERED POPS IN THIS PERIOD...ESPECIALLY IN THE AFTN.
MEDIUM RANGE MODELS HANDLING OF THE TROF MOVG INTO THE GRTLKS AND
ITS INTERACTION WITH WRN ATLANTIC HURRICANE SANDY HAS BEEN
ERRATIC... BUT THERE IS FAIR AGREEMENT ON 00Z RUNS THAT A RATHER
DEEP CLOSED/STACKED LOW WILL FORM OR MOVE INTO THE LWR GRTLKS EARLY
NEXT WEEK WITH IMPLICATION THAT WRN FRINGE OF ITS PRECIP SHIELD
AND/OR LAKE EFFECT OFF LAKE MICHIGAN WITH N-NW LOW LEVEL FLOW WOULD
IMPACT OUR AREA. STILL PLENTY OF UNCERTAINTY GIVEN POOR RUN-RUN
MODEL CONTINUITY AND CONSIDERABLE DIFFERENCES AMONG VARIOUS MODELS
ON DETAILS/EVOLUTION OF THE LOW... THUS BLEND OF MODELS AND PREVIOUS
FCST YIELDING JUST SLIGHT CHC POPS WAS FOLLOWED WITH ONLY COSMETIC
ADJUSTMENTS FOR DAYS6-7.
WITH LITTLE MOVEMENT AND GRADUAL DEEPENING OF UPR TROF OVER THE
GRTLKS THROUGH THE LONG TERM PERIOD... TEMPS SHOULD BE BLO NORMAL
WITH LITTLE DAILY CHANGE IN HIGHS/LOWS. FCST HIGHS GENERALLY IN THE
M-U40S AND LOWS IN THE L-M30S EACH DAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...JT
UPDATE...MARSILI
MARINE...MARSILI
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
754 AM EDT THU OCT 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST ALONG THE NORTHEASTERN SEABOARD INTO THE
WEEKEND. A COLD FRONT WILL APPROACH THE MID ATLANTIC FROM THE WEST
FRIDAY NIGHT. THIS COLD FRONT WILL STALL THROUGH THE WEEKEND AS WHAT
IS CURRENTLY HURRICANE SANDY TRACKS NORTH OFF THE EASTERN SEABOARD.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER RIDGE POLEWARD OF HURRICANE SANDY WILL CONTINUE TO AMPLIFY
OVER THE ERN CONUS TDA. AT THE SFC...HIPRES OVER COASTAL NEW ENGLAND
WILL BUILD SWWD ALONG THE MID-ATLANTIC COAST. LLVL ELY SURGE
ASSOCIATED WITH THE SWD-BUILDING HIGH HAS ADVECTED MARINE AIR/LOW
CLOUDS INLAND OVNGT. OVC STRATUS DECK...WHICH HAS REACHED WEST OF
BALTIMORE AND ANNAPOLIS /AS CAPTURED BY THE 07Z 11-3.9U SAT
IMAGERY/ WILL EXPAND WWD TOWARD THE BLUE RIDGE THRU DAYBREAK.
GIVEN LOWER SUN ANGLE PRESENT IN LATE OCT...IT MAY TAKE THE ENTIRE
MRNG FOR STRATUS DECK TO ERODE...POSSIBLY LONGER INTO THE AFTN
TOWARD THE CHSPK BAY. WEST OF THE STRATUS...MSTLY SUNNY SKIES
WILL YIELD MAX TEMPS IN UPPER 70S TO NEAR 80F ACROSS CENTRAL VA
AND POTOMAC HIGHLANDS...WHILE TEMPS MAY STRUGGLE TO REACH 70F IN
NORTH-CENTRAL MD.
SFC HIPRES WILL CONTINUE TO RIDGE SWD TOWARD THE MID-ATLANTIC COAST
TNGT. WITH PERSISTENT ELY FLOW...MARINE LAYER WILL BE WEDGED IN EAST
OF THE MTS. SATURATED BOUNDARY LAYER AND SHALLOW ISENTROPIC LIFT
BENEATH SUBSIDENCE INVERSION SHOULD SUPPORT DEVELOPMENT OF
STRATUS...DRIZZLE AND FOG OVNGT EAST OF THE BLUE RIDGE AND IN THE
SHENANDOAH VLY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
COMBINATION OF SFC HIGH CENTERED OVER NEW ENGLAND COAST AND
HURRICANE SANDY MOVING NORTH FROM THE BAHAMAS WILL PRODUCE AN
ONSHORE FLOW FRIDAY AND SATURDAY.
FRIDAY...LOW CLOUDS AND DRIZZLE/LIGHT RAIN WILL PERSIST INTO THE
MORNING...THEN MIX OUT MIDDAY THROUGH THE AFTERNOON. LATE OCT
ONSHORE FLOW OF 5 TO 10 MPH WOULD PROBABLY NORMALLY RESULT IN LOW
CLOUDS/DRIZZLE ALL DAY. HOWEVER...IT LOOKS LIKE THE FETCH AROUND THE
HIGH IS PLENTY DRY DESPITE COMING OFF THE ATLANTIC...SO EROSION OF
THE CLOUDS SHOULD OCCUR. MAX TEMPS LOW 70S.
FRIDAY NIGHT AND SATURDAY...GOOD CONSENSUS ON COLD FRONT APPROACHING
THE CENTRAL APPALACHIANS AND SANDY EXPANDING IN SIZE. ONSHORE FLOW
INCREASES TO 10 TO 15 MPH. LITTLE IN THE WAY OF PRECIP...PERHAPS
SOME RAIN BLUE RIDGE AND WEST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MUCH UNCERTAINTY EXISTS IN THE INTERPLAY OF THE COLD FRONT/TROUGH
DIGGING THROUGH THE MIDWEST AND SANDY FOR THIS WEEKEND AND WELL
INTO NEXT WEEK. NHC FORECAST IS STILL FOR A POST-TROPICAL
TRANSITION AS IT MOVES INTO COOLER WATER NORTH OF HATTERAS.
WHETHER THE HYBRID SYSTEM THEN PHASES WITH THE UPR TROUGH AND
IMPACTS THE MID ATLANTIC /PER 00Z ECMWF/ OR IMPACTS NEW ENGLAND
/PER 00Z GFS/ OR SOMETHING IN BETWEEN REMAINS THE BIG QUESTION.
EITHER WAY COLD CANADIAN AIR WILL BE SPILLING IN WITH THE TROUGH TO
THE WEST AND THERE IS A CHANCE FOR SNOW /WITH POSSIBLE
ACCUMULATIONS/ OVER THE ALLEGHENY HIGHLANDS STARTING SUNDAY NIGHT.
THERE IS STILL A WIDE RANGE OF POSSIBLE IMPACTS TO THE LWX CWA
SUNDAY INTO THE MIDDLE PART OF NEXT WEEK. PLEASE SEE FUTURE
FORECASTS FOR FURTHER DETAILS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AS OF 1145Z...EASTERLY LOW-LEVEL FLOW HAS PRODUCED A SHALLOW STRATUS
DECK WITH IFR CIGS. THIS DECK HAS MADE ITS WAY WESTWARD...COVERING
ALL OF THE TERMINALS EAST OF THE BLUE RIDGE. AND MRB IS EXPECTED TO
GO DOWN SHORTLY...BY 1230Z...BUT CHO SHOULD REMAIN VFR. THE BEST
MODEL THAT IS HANDLING THE LOW CIGS THIS MORNING IS THE 3KM HRRR.
QUICK PEEK AT THE LATEST 09Z HRRR SHOWS LOW CIGS LOCKED IN THROUGH
AT LEAST 18Z...ALTHO THERE SHOULD BE SOME LIFTING IN CIG BASE AS THE
MORNING PROGRESSES. BUT SHALLOW NATURE VS WEAK OCT SUN SUGGESTS THE
HRRR MIGHT BE RIGHT. FOR NOW...WILL KEEP SOME IMPROVEMENT FOR VFR IN
TAFS AFTER 17Z AT IAD/DCA...AND 18Z AT BWI/MTN. MVFR VSBYS WILL
PERSIST THIS MORNING AS WELL ASSOCIATED WITH THE STRATUS.
PREVIOUS DISCUSSION CONTINUES...
WITH ELY FLOW PERSISTING INTO TNGT...STRATUS SHOULD REDEVELOP DURING
THE LATE EVE/OVNGT. CONFIDENCE FOR IFR CIGS AND DZ AT ALL TERMINALS
RELATIVELY HIGH FOR 24 HOURS OUT.
ONSHORE FLOW 5 TO 10 KT AND IFR CIGS ERODE FRIDAY MIDDAY AND
AFTERNOON. FLOW INCREASES FRIDAY NIGHT AND SATURDAY WITH GUSTS
PERHAPS TO 15 KT. MUCH UNCERTAINTY THIS WEEKEND INTO NEXT WEEK WITH
THE TRACK OF WHAT IS CURRENTLY HURRICANE SANDY.
&&
.MARINE...
ELY FLOW 5-10 KT TDA AND TNGT. EXPECT AREAS OF DZ TO DEVELOP LATE
THIS EVE AND OVNGT.
EASTERLY FLOW WILL PERSIST THROUGH FRIDAY BEFORE TURNING
NORTHEASTERLY. SCA MAY BE WARRANTED SATURDAY NIGHT AS FLOW
INCREASES. SANDY WILL BE MOVING NORTHWARD EAST OF THE COASTLINE
SUNDAY AND MONDAY. THERE ARE MANY UNCERTAINTIES WITH THE TRACK BUT
GALE WRNGS MAY BE WARRANTED SUNDAY NIGHT AND MONDAY.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS WILL CONTINUE TO SLOWLY TO RISE AS EASTERLY FLOW SLOWLY
INCREASES THROUGH SATURDAY. WAXING MOON WILL BE FULL SUNDAY...
MAXIMIZING THE IMPACTS. MINOR THRESHOLDS MAY BE REACHED BY FRIDAY
AFTERNOON. POTENTIAL FOR MORE SIGNIFICANT IMPACTS SUNDAY AND MONDAY
AS WHAT IS NOW HURRICANE SANDY IS FCST TO BECOME POST TROPICAL
WHILE TRACKING NORTH. PLEASE MONITOR NATIONAL HURRICANE CENTER
PRODUCTS AND OUR HAZARDOUS WEATHER OUTLOOK FOR UPDATES ON THIS
SITUATION.
&&
.CLIMATE...
THE HIGH TEMPERATURE OF 84F YDA...24 OCT...AT DCA TIED THE DAILY
RECORD HIGH SET IN 2001. IT WAS ALSO THE LATEST DAY IN THE
CALENDAR YEAR TO REACH 84F SINCE 24 OCT 2001.
&&
.EQUIPMENT...
STARTING 18Z TDA...UPPER AIR OBSERVATIONS WILL BE CONDUCTED EVERY
6-H AT ALL NWS CONUS RAOB SITES...INCLUDING HERE AT WFO LWX...TO
SUPPORT FCST OPERATIONS FOR SANDY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...SMZ FOR AVIATION
PREV DISC...KLEIN/BAJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
622 AM CDT THU OCT 25 2012
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
THE MAIN AVIATION CONCERNS ARE WHEN THE TRANSITION OF -RA TO -SN
OCCURS ACROSS EASTERN MN OVER THE NEXT FEW HRS...AND HOW LONG IT
WILL STAY -SN...OR HAVE A MIXTURE OF RAIN/SNOW BY 18Z.
A LARGE CONVECTIVE BAND OF SHRA/TSRA HAS MOVED OFF TO THE EAST OF
THE FA...WITH ONLY EAU HAVING A SMALL CHC OF CONTINUING VCTS
BETWEEN 12-13Z. THE ZONE WHERE -RA CHG OVER TO SNOW IS NEAR RWF TO
STC...AND THE LOCAL DUAL-POL CC INDICATED THAT THE FREEZING LEVEL
HAS FALLEN OVER THE PAST HR OR TWO.
STARTED OUT WITH ONLY SNOW AT STC/RWF...WITH RNH/MSP CHG OVER
BETWEEN 15-16Z...AND EAU ARND 18-20Z. MODEL SOUNDINGS INDICATED
THAT WHEN THE ATMOSPHERIC COLUMN SATURATED BELOW ZERO...IT REMAINS
BELOW ZERO THRU THE AFTN AT AXN/RWF/RHN/MSP. THIS WOULD MEAN THAT
ONCE THE LT SNOW BEGAN IT WOULD CONTINUE AND NOT CHG OVER.
HOWEVER...SFC TEMPS WILL RANGE FROM 34 TO 38 DEGREES BY
18Z...MAKING FOR A MIXTURE MORE LIKELY. THEREFORE...CONTINUED
WITH A MIXTURE OF BOTH -SN/-RA AT RHN/MSP WHERE THE PRECIPITATION
WILL LINGER INTO THE EARLY AFTN. RWF/STC WILL LIKELY SEE THE
PRECIPITATION END BEFORE THE SWITCH OVER BACK TO -SN/-RA DEVELOPS.
WINDS WILL BE FROM THE NNW/NW DURING THE DAY...WITH GUSTS OVER
22-26 KTS. EXPECT SOME DECREASE IN THE OVERALL SPEED DURING THE
EVENING...ALONG WITH THE GUSTY WINDS ENDING.
KMSP...
HIGH END IFR/LOW END MVFR CIGS WILL CONTINUE THRU 18Z...WITH A
PERIOD OF MAINLY -RA THRU 15Z...THEN CHG OVER TO -SN...OR A
MIXTURE OF -SN/-RA BETWEEN 15-16Z. MOST OF THE PRECIPITATION
SHOULD TAPER OFF AFT 18Z...WITH CIGS RISING TO VFR AFT 21Z. GUSTY
WINDS WILL CONTINUE DURING THE DAYTIME HRS...WITH A FEW GUSTS OVER
24 KTS. WINDS WILL REMAIN FROM THE WNW OVERNIGHT.
/OUTLOOK FOR KMSP/
FRI AFTN...VFR. WINDS WNW 10 G 20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...MVFR/VFR. CHC -RASN. WINDS SE AT 5 KTS.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/JLT
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1000 AM EDT THU OCT 25 2012
.SYNOPSIS...
A BUILDING RIDGE OF HIGH PRESSURE BOTH ALOFT AND AT THE SURFACE WILL
RESULT IN DRY CONDITIONS AND MUCH ABOVE NORMAL TEMPERATURES FOR THE
REMINDER OF THIS WEEK. BY THE WEEKEND...AN APPROACHING COLD FRONT
WILL INCREASE THE CHANCES FOR PRECIPITATION...ALONG WITH COOLER
TEMPERATURES. THE REMNANTS OF TROPICAL SYSTEM SANDY COULD IMPACT THE
NORTH COUNTRY WITH RAIN AND WIND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1000 AM EDT THURSDAY...MINOR UPDATE TO SKY COVER THROUGH TODAY
TO ACCT FOR CURRENT OBSERVATIONAL DATA AND LATEST MID-LVL RH
PROGS....WHICH WOULD OFFER PTLY SUNNY ERN VT/SLV...AND MOSTLY
CLOUDY DACKS/CHVLY TODAY. ALSO OPTED TO CARRY AN OUTSIDE CHC OF A
SPRINKLE OR VERY LIGHT SHOWER ACROSS THE FAR NORTH...MAINLY NRN
SLV TODAY PER HRRR DATA AND RADAR SHOWING SOME LIGHT RETURNS NORTH
OF LAKE ONTARIO AS OF 14Z. PCPN AMNTS NEGLIGIBLE. REST OF FCST IN
GOOD SHAPE WITH HIGHS 50S TO AROUND 60 EAST...AND TO NEAR 70 SLV.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AS OF 400 AM EDT THURSDAY...TONIGHT...SOUNDINGS SHOW RH DECREASING
ACRS OUR FA...AS LARGE SCALE SUBSIDENCE DEVELOPS FROM BUILDING
RIDGE. IN ADDITION...SOUTH TO SOUTHWEST FLOW WL DEVELOP...WHICH WL
HELP PUSH DEEPER RH/MOISTURE NORTH OF OUR CWA. IN
ADDITION...SOUNDINGS SHOW GOOD BL MIXING TONIGHT AS GRADIENT
INCREASES FROM APPROACHING COLD FRONT...ESPECIALLY CV/SLV. THIS WL
HELP KEEP TEMPS IN THE U40S TO L50S AT BTV...WITH MUCH COOLER
TEMPS IN DEEPER MTN VALLEYS...WHERE WINDS WL DECOUPLE AND SKIES WL
CLR. THINKING M/U30S PARTS OF THE NECK AND L/M 40S DACKS/CENTRAL
VT.
MID/UPPER LVL RIDGE CONTS TO BUILD ACRS OUR CWA ON FRIDAY AND
SHIFTS TO OUR EAST BY SATURDAY...AS TROF/COLD FRONT APPROACH OUR
FA. THE COMBINATION OF WARM SOUTHERLY WINDS AND PROGGED 85H TEMPS
NEAR 12C AN 925MB TEMPS OF 15C....SUPPORT HIGHS IN THE M60S
NECK/MTNS TO M70S CV/SLV ON FRIDAY. NEAR RECORD HIGH TEMPS WL BE
POSSIBLE ON FRIDAY ACRS THE NORTH COUNTRY. PLEASE SEE CLIMO
SECTION BLW FOR RECORDS. SOUNDINGS SHOW DEEP DRY LAYER...WHICH WL
RESULT IN PLENTY OF SUNSHINE ACRS OUR FA ON FRIDAY. NAM CONTS TO
SHOW LLVL RH INCREASE ACRS OUR CWA ON SOUTH TO SOUTHEAST FLW EARLY
SATURDAY MORNING...WITH THE POTENTIAL FOR A LOW STRATUS DECK
DEVELOPING. MEANWHILE...GFS IS MUCH DRIER WITH RH PROFILES...AND
KEEPS BEST RH ASSOCIATED WITH APPROACHING COLD FRONT. NAM/GFS IN
GOOD AGREEMENT WITH POSITION OF SFC BOUNDARY ACRS NORTHERN NY BY
18Z SAT AND ENTERING THE CV BY 00Z SUNDAY. GIVEN...RIBBON OF
BETTER 850 TO 500MB RH AND SOME AREAS OF ENHANCED UVVS...WL
MENTION LIKELY POPS WESTERN CWA AND CHC ELSEWHERE. LLVL THERMAL
GRADIENT TIGHTENS ACRS OUR FA ON SATURDAY...WITH TEMPS RANGING
FROM THE 60S EAST TO 50S WEST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 400 AM EDT THURSDAY...BLOCKING PATTERN OVER THE CENTRAL ATLANTIC
TO HAVE AN IMPACT ON OUR WEATHER IN THE EXTENDED PERIOD FROM
SATURDAY NIGHT THROUGH THURSDAY. AT THIS TIME IT APPEARS THE UPPER
FLOW WILL BE BLOCKED THROUGH MUCH OF THE EXTENDED PERIOD AND THIS
MEANS IT WILL BE HARD TO HAVE WEATHER SYSTEMS PUSH EASTWARD. THIS
WILL HAVE PARTICULAR INTEREST FOR OUR AREA AS THIS MAY DRIVE WHERE
HURRICANE SANDY GOES. WHILE THERE ARE STILL DIFFERING SCENARIOS AS
TO HURRICANE SANDY`S PATH...ONE THING FOR SURE IS THAT IT WILL
MOVE NORTHWARD AND PHASE IN SOME WAY SHAPE OR FORM WITH UPSTREAM
UPPER LEVEL TROUGH. IT LOOKS LIKE THE MAIN TIME PERIOD THE IMPACTS
OF THIS SYSTEM WILL STILL BE MONDAY AND TUESDAY. THUS THE IDEA OF
RAIN LIKELY IN THE GOING FORECAST FOR MONDAY AND TUESDAY LOOKS
GOOD AND WILL NOT STRAY FROM THAT AT THIS POINT. GIVEN THE LONGER
DURATION OF RAIN AND THE MOISTURE BEING TROPICAL IN
NATURE...SYSTEM WILL HAVE TO BE WATCHED FOR ITS HEAVY RAIN
POTENTIAL. IN ADDITION...SYSTEM IS STRONG ENOUGH THAT GUSTY WINDS
WILL ALSO EXIST AND ATTENTION WILL BE PAID TO THE WEST SLOPES OF
THE GREEN MOUNTAINS AS THE EXPECTED TRACK OF THIS SYSTEM WOULD
ENHANCE THE POTENTIAL FOR DOWNSLOPE WINDS IN THIS AREA. WILL
UPDATE THE HAZARDOUS WEATHER OUTLOOK TO INDICATE THE POTENTIAL
REMAINS FOR HEAVY RAIN AND GUSTY WINDS EARLY NEXT WEEK. SYSTEM
WILL BE SLOW TO CLEAR THE AREA...SO GOING FORECAST OF A CHANCE OF
SHOWERS FOR WEDNESDAY LOOKS GOOD. COULD EASILY SEE THAT THREAT OF
PRECIPITATION CONTINUING RIGHT THROUGH THE END OF NEXT WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THROUGH 12Z FRIDAY...VFR CONDITIONS GENERALLY EXPECTED THROUGH
THE PERIOD. THE ONLY EXCEPTION TO THIS WILL BE AT KRUT WHERE MVFR
CEILINGS WILL EXIST DURING THE MORNING HOURS...OTHERWISE ANY
CEILINGS WILL GENERALLY BE AROUND 5000 FEET TODAY. SKIES SHOULD
GENERALLY BE CLEAR TONIGHT WITH SOME CLOUDS AROUND 1000 FEET...BUT
SHOULD NOT BE ENOUGH TO CALL A CEILING. WINDS WILL INCREASE OUT OF
THE SOUTH THIS MORNING...BUT SPEEDS WILL GENERALLY BE UNDER 15 KNOTS.
OUTLOOK 12Z FRIDAY THROUGH MONDAY...VFR CONDITIONS WL PREVAIL THRU
00Z SUNDAY...BEFORE APPROACHING SFC BOUNDARY INCREASES THE CLOUDS
AND CHCS FOR SHOWERS SAT NIGHT INTO SUNDAY. IN ADDITION...SOUTHEAST
FLOW AROUND HIGH PRESSURE...MAY PRODUCE SOME LOW CLOUDS AND MVFR
CONDITIONS AT MPV SATURDAY NIGHT/SUNDAY MORNING. THE HEAVIER
SHOWERS ON SUNDAY WL BE CAPABLE OF PRODUCING BRIEF PERIODS OF MVFR
IN LOW CIGS/VIS. COASTAL LOW MAY BRING MVFR/IFR COND WITH STRONG
WIND COND...WITH POSSIBLE LLWS.
&&
.CLIMATE...
BELOW ARE RECORD HIGH TEMPS FOR FRIDAY 10/26/12:
BTV 75 1963
MSS 72 1963
MPV 74 1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...JMG/TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LOCONTO
CLIMATE...WFO BTV
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
200 PM PDT THU OCT 25 2012
.SYNOPSIS...
WEAK HIGH PRESSURE HAS BEGUN TO MOVE OVER THE REGION. GENERALLY
MOSTLY CLEAR SKIES ARE EXPECTED THROUGH THE WEEKEND...EXCEPT
PATCHY VALLEY FOG IS POSSIBLE TONIGHT AND INTO FRIDAY MORNING.
TEMPERATURES WILL GRADUALLY WARM TO A FEW DEGREES ABOVE AVERAGE BY
THE WEEKEND.
&&
.DISCUSSION...
VISIBLE SATELLITE IMAGERY IS SHOWING LOW LEVEL CIRCULATION OFF THE
MONTEREY BAY COAST AND SLOWLY DRIFTING SOUTHWARD. HIGH-RES RAPID
REFRESH(HRRR) IS SHOWING DECREASING CLOUD COVER OVER THE VALLEY AS
THE LOW LEVEL CIRCULATION TRAVELS DUE SOUTH AND FURTHER OFFSHORE.
CURRENT TIMING HAS THE VALLEY CLEARING OUT JUST BEFORE SUNSET
BASED ON BOTH HRRR AND SREF SOLUTIONS. AT THIS POINT...THE BROAD
CYCLONIC CIRCULATION OVER THE WEST COAST CONTINUES TO SHIFT EAST
WITH A HIGH PRESSURE RIDGE AXIS MOVING CLOSER TO THE WEST COAST ON
FRIDAY. YET...SHORT RANGE MODELS DO NOT RELAX THE NORTHWESTERLY
FLOW ALOFT UNTIL AFTER FRIDAY AFTERNOON. THEREFORE...WITH LOCALLY
BREEZY WINDS ALOFT...FOG AND EXTREMELY COLD SURFACE TEMPERATURES
WILL NOT BE FAVORED OVER THE SAN JOAQUIN VALLEY FRIDAY MORNING.
HOWEVER...WILL KEEP A MENTION OF PATCHY FOG OVER THE SAN JOAQUIN
VALLEY FOR MORE RURAL AREAS THAT HAVE LESS OF A THRESHOLD TO FOG-
UP. IN ADDITION...TEMPERATURES WILL DROP OVERNIGHT...LOWER THEN
THURSDAY MORNING BUT NOT BY MUCH AS LOCAL WINDS WILL CONTINUE TO
BLOW FOR ONE MORE NIGHT.
AFTER FRIDAY...THE GENERAL TREND IS FOR CLEAR CONDITIONS WITH
WARMING TEMPERATURES THROUGH SUNDAY. GFS/ECMWF/UKMET/NOGAPS ALL
IN GOOD AGREEMENT WITH PLACING THE RIDGE AXIS OVER CALIFORNIA BY
SUNDAY AS THEY ALL FORM A REX BLOCKING PATTERN OVER THE NORTH-
CENTRAL PACIFIC. BY SUNDAY...GUIDANCE PLACES VALLEY MAX TEMP/S
SOME 3 TO 5 DEG-F ABOVE NORMAL BEFORE THE START OF ANOTHER COOLING
TREND. TOWARD NEXT WEEK...ALL LONGER RANGE MODELS ATTEMPT TO
BREAKDOWN THE REX BLOCK AND EJECT A TROF TOWARD THE PACIFIC
NORTHWEST/NOR- CAL BY TUESDAY NIGHT/WEDNESDAY. FEEL THAT MODELS
MAY BE PREMATURELY BREAKING DOWN THE REX BLOCK TOO SOON...WHICH
COULD LAST FOR A WEEK. DUE TO ALL MODELS DOING THIS BREAK DOWN...
CERTAINTY IS UP SLIGHTLY ON THE SOLUTION FOR EARLY NEXT WEEK. IF
THE TROF APPROACHES THE WEST COAST NEXT WEEK...IT WILL HAVE THE
DEAL WITH SANDY ALONG THE EAST COAST. EVEN WITH MODEL UNCERTAINTY
ON THE TROPICAL SYSTEM...SANDY...IT WILL EXIST OVER THE EAST COAST
EARLY NEXT WEEK. THEREFORE...THE RIDGE OVER THE MID-WEST WILL HAVE
TO AMPLIFY AS IT ADJUSTS TO THE APPROACHING TROF. MODELS DO
INDICATE THAT THE PRECIP BAND PUSHING ONTO CALIFORNIA WILL BE
FORCED TO SHIFT NORTHEAST AND POSSIBLY MISS CENTRAL CALIFORNIA.
THEREFORE...WILL ONLY MENTION A SLIGHT CHANCE OF PRECIP...STARTING
TUESDAY NIGHT...OVER THE NORTHERN THIRD OF THE DISTRICT FOR AREAS
FROM FRESNO COUNTY NORTHWARD.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THRU 00Z SATURDAY...EXCEPT LOCAL MVFR
IN MIST IN THE SAN JOAQUIN VALLEY 12Z TO 17Z FRIDAY.
&&
.AIR QUALITY ISSUES...
NONE.
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 10-25 91:1966 61:1998 62:1982 36:1971
KFAT 10-26 89:2003 57:2004 58:1927 35:1939
KFAT 10-27 89:2003 58:1896 61:1987 35:1970
KBFL 10-25 94:1917 62:1939 66:1982 35:1899
KBFL 10-26 92:2003 58:1996 61:1959 35:1939
KBFL 10-27 99:1906 56:2004 64:1987 34:1919
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...MOLINA
AVN/FW...BEAN
SYNOPSIS...BSO
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
252 PM EDT THU OCT 25 2012
.SHORT TERM...HURRICANE SANDY CONTINUES TO PLOW THROUGH THE BAHAMAS
STILL AT CATEGORY 2 WITH 105 MPH MAX SUSTAINED WINDS. BROAD E TO
NE FLOW CONTINUES TO PROVIDE A FEED OF MOSTLY LOW LEVEL MOISTURE INTO
THE AREA WITH A FEW SHOWERS BEGINNING TO IMPACT FLAGLER COUNTY.
PWATS ARE ABOUT 1.2 TO 1.3 INCHES PER RAP MODEL AND BLENDED TOTAL
PRECIP WATER...AND WATER VAPOR IMAGERY STILL SHOWS DRIER AIR IN
THE MID AND UPPER LEVELS.
FOR TONIGHT...SIMILAR TO LAST NIGHT BREEZY/WINDY E TO NE WINDS CAN BE
EXPECTED IN THE EVENING AND TAPER OFF OVERNIGHT. WILL ALLOW THE LAKE
WIND ADVISORY FOR THE GA COAST TO END THIS EVENING. ELSEWHERE...T.S.
WATCH WILL BE CONTD AT THIS TIME. ISOLD TO POSSIBLY BRIEFLY SCT
SHOWER ACTIVITY CAN BE EXPECTED MAINLY FOR ERN ZONES. CURRENT MOS
GUIDANCE CONTINUES TO LOOK A BIT LOW PER RADAR IMAGERY. LOWS IN THE
LOWER TO MID 60S EXPECTED WITH NEAR 70 TEMPS NEAR THE COAST.
GUIDANCE SUGGESTS PATCHY FOG FOR WELL INLAND SE GA WHICH LOOKS
PLAUSIBLE GIVEN THE HIGHER DEWPOINT AIR AND DRY CONDITIONS ALOFT AND
WINDS MAY RELAX TO ABOUT 3-5 MPH UP THERE.
FRIDAY...STRONG NELY WINDS EXPECTED AS SANDY TRANSLATES NWD TO THE
NRN BAHAMAS AND STRENGTHENS THE PRES GRADIENT. WINDS OF 25-35 MPH
POSSIBLE WITH GUSTS NEAR 40-45 MPH POSSIBLE. THESE WINDS WILL BE
MORE POSSIBLE NEARER TO THE COAST. SOME BANDS OF COASTAL SHOWERS ARE
ANTICIPATED EARLY AND INCREASING RAIN CHANCES ARE EXPECTED FROM SE
TO NW AS MOISTURE INCREASES FROM THAT DIRECTION. ISOLD EMBEDDED
TSTMS ARE ANTICIPATED OVER THE SE ZONES AND COASTAL WATERS AND MAY
PRODUCE STRONGER WIND GUSTS IN PERIODS OF RAIN. FRI NIGHT...SANDY
WILL BE AT POINT OF CLOSEST APPROACH AS THE NHC JOGS THE SYSTEM A
BIT NNW. THE SYSTEM IS THEN PROJECTED TO LIFT N AND THEN NNE LATE.
WINDY CONDITIONS ARE EXPECTED ALONG THE COASTAL COUNTIES. ELEVATED
RAIN CHANCES EXPECTED BUT MAINLY IN THE CHANCE CATEGORY OVER THE SE
1/3RD OF THE CWA. SOME TSTM POTENTIAL STILL POSSIBLE E ZONES/MARINE
ZONES. SUSTAINED WINDS NEAR 25-35 MPH POSSIBLE ALONG THE COASTAL
AREAS FROM FERNANDINA TO FLAGLER BEACH. LOWS IN THE 60S EXPECTED.
SATURDAY...SANDY IS EXPECTED TO LIFT NEWD AT A FASTER CLIP BUT
BANDS OF SHOWERS ARE STILL ANTICIPATED AT THIS TIME OVER THE ERN
ZONES WITH WINDY CONDITIONS PREVAILING. SOME GLARING DIFFERENCES IN
MODEL WINDS AT 850 MB AND GFS IS THE MODEL OF CHOICE HERE. RAIN
CHANCES ARE EXPECTED TO DIMINISH THROUGH THE AFTN AND EARLY
EVENING AS DEEP MOISTURE AROUND THE SYSTEM MOVES OUT TO SEA. TSTM
POTENTIAL LOOKS TOO LOW TO MENTION AT THIS TIME. HIGHS IN THE 70S
TO NEAR 80. SAT NIGHT TO SUNDAY...COOLER AND DRIER CONDITIONS EXPECTED
AS THE SYSTEM PULLS AWAY WITH DEEP NW FLOW ANTICIPATED. LOWS IN
THE 50S EXPECTED AREA WIDE. HIGHS IN THE 70S ON SUNDAY.
.LONG TERM...MONDAY-THURSDAY.
MUCH COOLER AND DRIER NW FLOW EXPECTED FOR MOST OF THE TIME PERIOD
AS WEAK SFC HIGH PRESSURE BUILDS INTO THE REGION. SOME TROUGHING
WILL BE POSSIBLE BY MID WEEK AND MAY SUPPORT LOW END RAIN CHANCES
NEAR 20%. TEMPERATURES WILL BE AT OR BELOW NORMAL DURING THE EXTENDED
FORECAST.
&&
.AVIATION...MAINLY VFR CONDS WITH OCNL CIGS 3500-5000 FT. ISOLATED
COASTAL SHOWERS WILL CONTINUE TO MOVE INLAND AND HAVE VCSH AT ALL
TERMINALS.
&&
.MARINE...WILL CONTINUE WITH THE TROPICAL STORM WARNING FOR
THE COASTAL WATERS. WINDS AND SEAS WILL CONTINUE TO INCREASE
AS THE GRADIENT TIGHTENS BETWEEN HURRICANE SANDY AND HIGH PRESSURE
TO THE NORTH. EXPECTING TROPICAL STORM CONDITIONS BY LATE TONIGHT
INTO SATURDAY NIGHT WITH CONDITIONS BEGINNING TO IMPROVE
SUNDAY.
RIP CURRENTS/SURF: HIGH RISK OF DANGEROUS RIP CURRENTS WILL
CONTINUE INTO THE WEEKEND. BREAKER HEIGHTS WILL INCREASE TO
8 TO 12 FEET FRIDAY INTO THE WEEKEND. HAVE ISSUED A HIGH
SURF ADVISORY BEGINNING TONIGHT INTO SUNDAY MORNING.
MINOR TO MODERATE COASTAL FLOODING IS POSSIBLE DURING HIGH
TIDES ON FRIDAY AND SATURDAY AND A COASTAL FLOOD ADVISORY
MAY BE NEEDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 62 82 61 77 / 10 10 10 10
SSI 69 78 67 75 / 20 20 50 50
JAX 68 81 64 76 / 20 20 40 40
SGJ 74 83 70 76 / 20 40 60 50
GNV 65 82 64 78 / 10 10 30 20
OCF 68 83 65 79 / 10 20 30 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CLAY-MARION-
PUTNAM.
TROPICAL STORM WATCH FOR DUVAL-FLAGLER-NASSAU-ST JOHNS.
GA...HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR COASTAL CAMDEN-
COASTAL GLYNN.
LAKE WIND ADVISORY UNTIL 6 AM EDT FRIDAY FOR COASTAL CAMDEN-
COASTAL GLYNN.
HIGH SURF ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SUNDAY FOR
COASTAL CAMDEN-COASTAL GLYNN.
AM...TROPICAL STORM WARNING FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH
FL 20 NM TO 60 NM OFFSHORE-ALTAMAHA SOUND GA TO FERNANDINA
BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL 20
NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL
OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM.
&&
$$
SHASHY/PETERSON/WALKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
521 PM CDT THU OCT 25 2012
.DISCUSSION...
336 PM CDT
PREVIOUS DISCUSSION...
1251 PM CDT
THIS UPDATE STILL VALID FOR REST OF AFTERNOON AND EARLY
EVENING...
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE
DID SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE
ROCKFORD AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN
6PM AND 8PM DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE
SUGGESTS 300-500 J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH
50-60KT DEEP LAYER SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE
ALONG THE FRONT OVER NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS
TO LIFT NORTHEAST ACROSS IOWA EARLY THIS AFTERNOON. WITH INTENSE
SHEAR NOTED IMMEDIATELY ALONG AND JUST BEHIND THE FRONT...WILL
HAVE TO MONITOR FOR A MARGINAL SEVERE WEATHER THREAT THROUGH THE
AFTERNOON AND EARLY EVENING AS FAST MOVING THUNDERSTORMS ARE
EXPECTED TO DEVELOP.
BMD
DISCUSSION...LATE TONIGHT AND BEYOND...
300 PM CDT
SHARP COLD FRONT TO HAVE MOVED TO NORTH CENTRAL AND WEST CENTRAL
IN BY MIDNIGHT...WITH ONLY SOME LINGERING POST FRONTAL LIGHT
SHOWERS INTO THE OVERNIGHT HOURS FROM NORTHWEST IN TO E CENTRAL
IL. WITH THE FRONT AND THE POST FRONTAL SHOWERS HAVING MOVED EAST
OF THE LOCAL FORECAST AREA DURING THE PREDAWN HOURS THE CLEARING
SEEN UPSTREAM OVER SOUTHERN NE AND MUCH OF KS IS EXPECTED TO
SPREAD INTO NORTHWEST AND WEST CENTRAL IL BY LATE
EVENING...CONTINUING EASTWARD TO FAR NORTHEASTERN IL BY DAWN
FRIDAY.
THIS MORNING/S 12Z RAOBS SHOWED THAT BEHIND THE FRONT THAT COLD
AIR HAD PENETRATED AS FAR SOUTH AS SOUTHERN NE WITH KLBF
MEASURING AN 850 HPA TEMPERATURE OF -5C. THIS IS IN CONTRAST TO
+15C REPORTED AT BOTH KTOP AND KDVN. THIS AIR WAS COLD ENOUGH TO
SUPPORT SNOW THIS MORNING IN PARTS OF MN...IA AND NE.
WHILE THE FRONTAL PASSAGE SHIFTS LOW LEVEL WINDS TO OUT OF THE
NORTH-NORTHWEST AND NORTHWEST AND DROPS SURFACE TEMPERATURES
SIGNIFICANTLY TONIGHT...THE FLOW LOCALLY 850 AND 800 HPA IS
EXPECTED TO BACK TO WEST AND THE SOUTHWEST AT INCREASING HEIGHTS.
THIS IS IN RESPONSE TO THERE ONLY VERY SLIGHT MID AND UPPER
VEERING OF THE FLOW INDICATED DUE TO ANOTHER STRONG JET MAX AND
SHORT WAVE TROUGH TO ROTATE NORTHEASTWARD FROM THEE CENTRAL
PLAINS TO THE UPPER MIDWEST DURING THE NIGHT. THIS WEST TO
SOUTHWEST FLOW ABOVE THE BOUNDARY LAYER KEEPS THE COOL AIR
OVER THE LOCAL AREA RATHER SHALLOW AND ANY PRECIPITATION
LINGERING INTO THE NIGHT IS EXPECTED TO REMAIN LIQUID...ENDING
BEFORE THE COLD AIR DEEPENS WITH THE PASSAGE OF THE UPSTREAM
SHORT WAVE.
WITH 850 HPA TEMPERATURE PROGS AVERAGING ABOUT +1 TO -2C OVER THE
FORECAST AREA DURING THE DAY FRIDAY AFTERNOON TEMPERATURES SHOULD
ONLY RECOVER TO UPPER 40S AND LOWER 50S IN THE AFTERNOON. ANOTHER
SHORT WAVE TO MOVE ACROSS THE REGION LATE FRIDAY NIGHT AND EARLY
SATURDAY REINFORCES THE LOW LEVEL COLD AIR...WHICH IS EXPECTED TO
LIMIT MAX TEMPS FOR SATURDAY TO GENERALLY THE 45-50 DEG F
RANGE...WITH SIMILAR HIGHS FOR SUNDAY AND MONDAY.
NORTHWEST WINDS GRADUALLY VEER TO NORTH FRIDAY NIGHT AND
NORTH-NORTHEAST SATURDAY BEFORE BACKING A BIT TO NORTH DURING
SUNDAY AND INTO MONDAY. WHILE TEMPERATURE DIFFERENTIAL BETWEEN
THE LAKE AND THE COLD LOW LEVEL AIR IS SUFFICIENT FOR LAKE EFFECT
INITIATION PER MODEL FORECAST TEMPERATURE PROFILES ANY
SIGNIFICANTLY VERTICAL GROWTH IS TO BE CAPPED BY AN OVERLYING
INVERSION. THUS...ONLY EXPECT SOME LAKE EFFECT CLOUDS SATURDAY
NIGHT AND SUNDAY NEAR THE LAKE AND INLAND TO THE KANKAKEE RIVER
VALLEY OF NORTHWEST IN AND FAR NORTHEAST IL...ALONG AND NEAR THE
IL-IN STATE LINE. BY SUNDAY NIGHT THIS INVERSION LESSENED AND
EVENTUALLY ELIMINATED ALLOWING A SMALL CHANCE OF LAKE EFFECT SNOW
AND RAIN SHOWERS SUNDAY NIGHT INTO MONDAY NIGHT.
HOW LONG THE REGION REMAINS UNDER DEEP NORTH TO NORTHWEST FLOW
AND THE VERY COOL AIR MASS DEPENDS ON HOW THE HURRICANE SANDY
INTERACTS WITH THE UPPER TROUGH TO BE LOCATED FROM WESTERN HUDSON
BAY ACROSS ONTARIO AND THE UPPER GREAT LAKES MONDAY. MODELS IN
PRETTY GOOD AGREEMENT IN TURNING SANDY NORTH-NORTHWESTWARD TO
OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND COASTS LATE
TUESDAY AND TUESDAY NIGHT. MODELS THEN CONTINUE TO MOVE THE
EXTRA- TROPICAL SYSTEM NORTH-NORTHWEST OVER THE LOWER GREAT LAKES
DURING LATER TUESDAY AND TUESDAY NIGHT...AND TO FAR SOUTHERN
QUEBEC BY THURSDAY MORNING. THIS SUGGESTS THAT THE VERY COOL AIR
MASS WILL BE LOCKED IN PLACE OVER THE REGION UNTIL AT LEAST LATE
INTO NEXT WEEK KEEPING THE STRING OF BELOW NORMAL TEMPERATURE
CONDITIONS GOING.
SOME INDICATION THAT AS THE SYSTEM MOVES TO THE LOWER GREAT LAKES
AND SOUTHERN QUEBEC THAT MOISTURE WILL BE WRAPPED WEST AND
SOUTHWESTWARD TO THE UPPER GREAT LAKES FOR LATER TUESDAY AND
WEDNESDAY WHICH BRINGS A SLIGHT CHANCE RAIN OR RAIN AND SNOW
ALMOST TO THE WESTERN SHORE OF LAKE MI. HAVE SLIGHT CHANCES INTO
NORTHWEST IN WHILE HAVE KEPT NORTHEAST IL BELOW THE SLIGHT CHANCE
POP THRESHOLD AS WAY TOO MUCH UNCERTAINTY AT THIS POINT.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* WIND SHIFT TO WEST IMMINENT
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT.
IZZI
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010.
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY
SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
339 PM CDT THU OCT 25 2012
.DISCUSSION...
336 PM CDT
PREVIOUS DISCUSSION...
1251 PM CDT
THIS UPDATE STILL VALID FOR REST OF AFTERNOON AND EARLY
EVENING...
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE
DID SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE
ROCKFORD AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN
6PM AND 8PM DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE
SUGGESTS 300-500 J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH
50-60KT DEEP LAYER SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE
ALONG THE FRONT OVER NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS
TO LIFT NORTHEAST ACROSS IOWA EARLY THIS AFTERNOON. WITH INTENSE
SHEAR NOTED IMMEDIATELY ALONG AND JUST BEHIND THE FRONT...WILL
HAVE TO MONITOR FOR A MARGINAL SEVERE WEATHER THREAT THROUGH THE
AFTERNOON AND EARLY EVENING AS FAST MOVING THUNDERSTORMS ARE
EXPECTED TO DEVELOP.
BMD
DISCUSSION...LATE TONIGHT AND BEYOND...
300 PM CDT
SHARP COLD FRONT TO HAVE MOVED TO NORTH CENTRAL AND WEST CENTRAL
IN BY MIDNIGHT...WITH ONLY SOME LINGERING POST FRONTAL LIGHT
SHOWERS INTO THE OVERNIGHT HOURS FROM NORTHWEST IN TO E CENTRAL
IL. WITH THE FRONT AND THE POST FRONTAL SHOWERS HAVING MOVED EAST
OF THE LOCAL FORECAST AREA DURING THE PREDAWN HOURS THE CLEARING
SEEN UPSTREAM OVER SOUTHERN NE AND MUCH OF KS IS EXPECTED TO
SPREAD INTO NORTHWEST AND WEST CENTRAL IL BY LATE
EVENING...CONTINUING EASTWARD TO FAR NORTHEASTERN IL BY DAWN
FRIDAY.
THIS MORNING/S 12Z RAOBS SHOWED THAT BEHIND THE FRONT THAT COLD
AIR HAD PENETRATED AS FAR SOUTH AS SOUTHERN NE WITH KLBF
MEASURING AN 850 HPA TEMPERATURE OF -5C. THIS IS IN CONTRAST TO
+15C REPORTED AT BOTH KTOP AND KDVN. THIS AIR WAS COLD ENOUGH TO
SUPPORT SNOW THIS MORNING IN PARTS OF MN...IA AND NE.
WHILE THE FRONTAL PASSAGE SHIFTS LOW LEVEL WINDS TO OUT OF THE
NORTH-NORTHWEST AND NORTHWEST AND DROPS SURFACE TEMPERATURES
SIGNIFICANTLY TONIGHT...THE FLOW LOCALLY 850 AND 800 HPA IS
EXPECTED TO BACK TO WEST AND THE SOUTHWEST AT INCREASING HEIGHTS.
THIS IS IN RESPONSE TO THERE ONLY VERY SLIGHT MID AND UPPER
VEERING OF THE FLOW INDICATED DUE TO ANOTHER STRONG JET MAX AND
SHORT WAVE TROUGH TO ROTATE NORTHEASTWARD FROM THEE CENTRAL
PLAINS TO THE UPPER MIDWEST DURING THE NIGHT. THIS WEST TO
SOUTHWEST FLOW ABOVE THE BOUNDARY LAYER KEEPS THE COOL AIR
OVER THE LOCAL AREA RATHER SHALLOW AND ANY PRECIPITATION
LINGERING INTO THE NIGHT IS EXPECTED TO REMAIN LIQUID...ENDING
BEFORE THE COLD AIR DEEPENS WITH THE PASSAGE OF THE UPSTREAM
SHORT WAVE.
WITH 850 HPA TEMPERATURE PROGS AVERAGING ABOUT +1 TO -2C OVER THE
FORECAST AREA DURING THE DAY FRIDAY AFTERNOON TEMPERATURES SHOULD
ONLY RECOVER TO UPPER 40S AND LOWER 50S IN THE AFTERNOON. ANOTHER
SHORT WAVE TO MOVE ACROSS THE REGION LATE FRIDAY NIGHT AND EARLY
SATURDAY REINFORCES THE LOW LEVEL COLD AIR...WHICH IS EXPECTED TO
LIMIT MAX TEMPS FOR SATURDAY TO GENERALLY THE 45-50 DEG F
RANGE...WITH SIMILAR HIGHS FOR SUNDAY AND MONDAY.
NORTHWEST WINDS GRADUALLY VEER TO NORTH FRIDAY NIGHT AND
NORTH-NORTHEAST SATURDAY BEFORE BACKING A BIT TO NORTH DURING
SUNDAY AND INTO MONDAY. WHILE TEMPERATURE DIFFERENTIAL BETWEEN
THE LAKE AND THE COLD LOW LEVEL AIR IS SUFFICIENT FOR LAKE EFFECT
INITIATION PER MODEL FORECAST TEMPERATURE PROFILES ANY
SIGNIFICANTLY VERTICAL GROWTH IS TO BE CAPPED BY AN OVERLYING
INVERSION. THUS...ONLY EXPECT SOME LAKE EFFECT CLOUDS SATURDAY
NIGHT AND SUNDAY NEAR THE LAKE AND INLAND TO THE KANKAKEE RIVER
VALLEY OF NORTHWEST IN AND FAR NORTHEAST IL...ALONG AND NEAR THE
IL-IN STATE LINE. BY SUNDAY NIGHT THIS INVERSION LESSENED AND
EVENTUALLY ELIMINATED ALLOWING A SMALL CHANCE OF LAKE EFFECT SNOW
AND RAIN SHOWERS SUNDAY NIGHT INTO MONDAY NIGHT.
HOW LONG THE REGION REMAINS UNDER DEEP NORTH TO NORTHWEST FLOW
AND THE VERY COOL AIR MASS DEPENDS ON HOW THE HURRICANE SANDY
INTERACTS WITH THE UPPER TROUGH TO BE LOCATED FROM WESTERN HUDSON
BAY ACROSS ONTARIO AND THE UPPER GREAT LAKES MONDAY. MODELS IN
PRETTY GOOD AGREEMENT IN TURNING SANDY NORTH-NORTHWESTWARD TO
OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND COASTS LATE
TUESDAY AND TUESDAY NIGHT. MODELS THEN CONTINUE TO MOVE THE
EXTRA- TROPICAL SYSTEM NORTH-NORTHWEST OVER THE LOWER GREAT LAKES
DURING LATER TUESDAY AND TUESDAY NIGHT...AND TO FAR SOUTHERN
QUEBEC BY THURSDAY MORNING. THIS SUGGESTS THAT THE VERY COOL AIR
MASS WILL BE LOCKED IN PLACE OVER THE REGION UNTIL AT LEAST LATE
INTO NEXT WEEK KEEPING THE STRING OF BELOW NORMAL TEMPERATURE
CONDITIONS GOING.
SOME INDICATION THAT AS THE SYSTEM MOVES TO THE LOWER GREAT LAKES
AND SOUTHERN QUEBEC THAT MOISTURE WILL BE WRAPPED WEST AND
SOUTHWESTWARD TO THE UPPER GREAT LAKES FOR LATER TUESDAY AND
WEDNESDAY WHICH BRINGS A SLIGHT CHANCE RAIN OR RAIN AND SNOW
ALMOST TO THE WESTERN SHORE OF LAKE MI. HAVE SLIGHT CHANCES INTO
NORTHWEST IN WHILE HAVE KEPT NORTHEAST IL BELOW THE SLIGHT CHANCE
POP THRESHOLD AS WAY TOO MUCH UNCERTAINTY AT THIS POINT.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
232 PM CDT THU OCT 25 2012
.DISCUSSION...
1251 PM CDT
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE DID
SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE ROCKFORD
AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN 6PM AND 8PM
DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE SUGGESTS 300-500
J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH 50-60KT DEEP LAYER
SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE ALONG THE FRONT OVER
NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS TO LIFT NORTHEAST ACROSS
IOWA EARLY THIS AFTERNOON. WITH INTENSE SHEAR NOTED IMMEDIATELY
ALONG AND JUST BEHIND THE FRONT...WILL HAVE TO MONITOR FOR A
MARGINAL SEVERE WEATHER THREAT THROUGH THE AFTERNOON AND EARLY
EVENING AS FAST MOVING THUNDERSTORMS ARE EXPECTED TO DEVELOP. BMD
//PREV DISCUSSION...
333 AM CDT
EARLY THIS MORNING AN ACTIVE ATMOSPHERIC RIVER WAS RIDING ALONG THE
FRONTAL BOUNDARY FROM CENTRAL KANSAS NORTHEAST THROUGH LAKE
SUPERIOR. A SERIES OF CONVECTIVE COMPLEXES DEVELOPED LATE LAST NIGHT
AND CONTINUE EARLY THIS MORNING. ACROSS NORTHERN IL/NORTHWEST IN
FLOW REMAINS SOUTHERLY WITH VERY MILD AND MOIST CONDS. DEW PTS HAVE
REMAINED IN THE LOW 60S OVERNIGHT...WHICH BASED ON CLIMATOLOGY IS A
FEW DEGREES WARMER THAN THE NORMAL HIGH TEMPS ON THIS DATE. IT
APPEARS THE DAY WILL START OFF WITH JUST SOME HIGH BASED CLOUDS
OVERHEAD...WHICH WILL ALLOW THE SFC TO WARM-UP EFFICIENTLY. WITH
SOME POTENTIAL FOR COMPRESSIONAL WARMING TO TAKE PLACE...TEMPS
ACROSS THE CWFA COULD EASILY PUSH BACK INTO THE UPR 70S TDY...AND
COULD SEE A FEW 80 DEG READINGS SOUTH OF A PONTIAC TO KANKAKEE LINE.
THEN THE LARGER FOCUS WILL BE ON THE PRECIP ARRIVAL...CONVECTION
CHANCES...AND FRONTAL PASSAGE. MINIMAL ADJUSTMENTS TO THE PREVIOUS
FORECAST...AS IT APPEARS THE FRONT SHUD ARRIVE ACROSS THE FAR
WESTERN CWFA ARND 18-21Z. LAPSE RATES STEEPEN...AND MUCAPE VALUES
ARE PROGGED TO APPROACH 1000J/KG THIS AFTN. THE BEST SHEAR SHUD PASS
WELL NORTH OF THE REGION...HOWEVER THE ENVIRONMENT OVERHEAD WILL
BECOME FAVORABLE FOR CONVECTION EARLY THIS AFTERNOON THROUGH EARLY
THIS EVENING FROM WEST TO EAST. HI-RES GUIDANCE WAS SUGGESTING THAT
PRECIP MAY BE MORE PLENTIFUL IMMEDIATELY BEHIND THE BNDRY. HAVE
MAINTAINED MENTION OF CONVECTION...HOWEVER HAVE TRIMMED BACK FROM
THE DEFINITE MENTION TO LIKELY. COULD EVEN SEE THIS BEING TRIMMED
BACK TO CHC THUNDER.
THEN THE BDNRY STEADILY MARCHES EAST ACROSS THE CWFA WITH WINDS
TURNING WEST/NORTHWEST BY 00Z...AND EXPECT THE FRONT TO HAVE PUSHED
EAST OF NORTHWEST IN AROUND 3Z FRI. THE CONVECTIVE THREAT WILL
RAPIDLY DIMINISH AS WELL AS THE DRY AIR STEADILY ARRIVES LATE THIS
AFTN. TEMPS WILL ALSO QUICKLY FALL POST FRONTAL...AND EXPECT BY 00Z
LOCATIONS WEST OF A PONTIAC TO CRYSTAL LAKE LINE WILL HAVE TEMPS
ALREADY IN THE UPR 40S. THEN THEY WILL CONTINUE TO RADIATE WITH LOWS
IN THE MID 30S ACROSS THE FAR NORTHWEST...AND LOW 40S FOR NORTHWEST
IN.
FRIDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL PUSH EAST ACROSS THE GREAT LAKES REGION
FRI...THEN BEGIN TO WEAKEN THROUGH THE SECOND HALF OF THE WEEKEND.
HOWEVER...DESPITE THE WEAKENING THE GENERAL THEME WILL FEATURE A
NORTHWEST FLOW. STRONG 500MB RIDGE WILL REMAIN IN PLACE ACROSS THE
CANADIAN MARITIME THROUGH THE WEEKEND...WHICH COULD SLOW THE
WEAKENING OF THE TROUGH OVER THE GREAT LAKES. ENSEMBLES ARE
DEMONSTRATING MINIMAL SPREAD AMONGST EACH MEMBER...THUS EXHIBITING A
HIGH CONFIDENCE.
SFC ANTI-CYCLONIC FLOW RAPIDLY PUSHES IN BEHIND THE COLD FRONT
FRI...AND SHUD AID IN A QUICK EROSION TO THE CLOUDS/PRECIP. 850MB
THERMAL TROUGH WILL STEADILY BUILD OVERHEAD FRI...WITH TEMPS MIDDAY
OF 0 TO -2 DEG C. AT THIS TIME IT APPEARS THE BULK OF FRI WILL
REMAIN DRY...HOWEVER CONDITIONS WILL BE STEADILY DEVELOPING FOR LAKE
EFFECT PRECIP GENERATION FRI EVE.
LAKE EFFECT PRECIP LOOKS PROBABLE FOR FRI NGT THRU SUN...AS FLOW
WILL GENERALLY BE NORTH. AT TIMES THE WINDS MAY VEER MORE TO THE
NORTHEAST...WHICH WOULD FAVOR A BUCKLE IN THE EXPECTED LAKE EFFECT
PRECIP COVERAGE AND PUSH IT OVER CHICAGO/WAUKEGAN. TEMPS DURING THE
DAY SHUD WARM ENOUGH TO KEEP PRECIP IN A LIQUID STATE OR SHRA. THEN
OVERNIGHT TEMPS ARE EXPECTED TO RADIATE INTO THE LOW/MID 30S...WHICH
MAY ALLOW FOR SOME WET SNOW TO BECOME MIXED WITH THE LGT RA.
OTHERWISE AREAS AWAY FROM LAKE MICHIGAN OR WEST OF I-355...SHOULD
SEE DRY WEATHER THRU THE FRI-SUN PERIODS AND PSBLY SUNNY SKIES.
AFTERNOON TEMPS SAT/SUN WILL STRUGGLE TO WARM WITH THE CONTINUED
FEED OF COLD AIR ADVECTION INTO THE AREA. BASED OFF OF THE PLUMES
AND GUIDANCE FOR THIS TIMEFRAME...MANY LOCATIONS MAY STRUGGLE TO
WARM BEYOND THE LOW/MID 40S. IT IS CONCEIVABLE THAT A FEW AREAS
NORTH OF I-88 COULD SEE TEMPS HOLD IN THE UPR 30S SAT.
MONDAY THROUGH WEDNESDAY...
THE FINAL FEW PERIODS OF THE EXTENDED BECOME VERY CHALLENGING. THE
AFOREMENTIONED HIGH LATITUDE RIDGING OVER THE CANADIAN MARITIME IS
PROGGED TO MAINTAIN ITSELF...AND GUIDANCE IS INDICATING THAT THE
TROUGH OVER THE GREAT LAKES WILL INITIALLY WEAKEN. THEN THIS TROUGH
WILL UNDERGO SOME ENHANCEMENT TUE/WED. THE OTHER CHALLENGE IS THE
TROPICAL SYSTEM IN THE WESTERN ATLANTIC...WHICH GUIDANCE HAS BEEN
SUGGESTING WILL SKIRT THE EAST COAST.
ONCE THE TROPICAL SYSTEM...SANDY...APPROACHES THE NEW ENGLAND AREA
GUIDANCE IS SUGGESTING IT WILL MERGE WITH THE TROUGH AND AMPLIFY.
THIS COULD RESULT IN A SLUG OF PRECIP PIVOTING WEST/SOUTHWEST ACROSS
LOWER MICHIGAN TUE AND ARRIVE ACROSS NORTHERN IL/NORTHWEST IN TUE
NGT/WED.
OVERALL THE TEMP OUTLOOK FOR THE EXTENDED PERIODS WILL REMAIN
COOL...WITH TEMPS GENERALLY IN THE MID/UPR 40S TO PSBLY LOW 50S
TUE/WED. OVERNIGHT LOWS WILL HINGE UPON CLOUD COVER...HOWEVER AT
THIS TIME ANTICIPATE TEMPS IN THE UPR 20S TO LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1252 PM CDT THU OCT 25 2012
.DISCUSSION...
1251 PM CDT
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE DID
SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE ROCKFORD
AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN 6PM AND 8PM
DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE SUGGESTS 300-500
J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH 50-60KT DEEP LAYER
SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE ALONG THE FRONT OVER
NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS TO LIFT NORTHEAST ACROSS
IOWA EARLY THIS AFTERNOON. WITH INTENSE SHEAR NOTED IMMEDIATELY
ALONG AND JUST BEHIND THE FRONT...WILL HAVE TO MONITOR FOR A
MARGINAL SEVERE WEATHER THREAT THROUGH THE AFTERNOON AND EARLY
EVENING AS FAST MOVING THUNDERSTORMS ARE EXPECTED TO DEVELOP. BMD
&&
.PREV DISCUSSION...
333 AM CDT
EARLY THIS MORNING AN ACTIVE ATMOSPHERIC RIVER WAS RIDING ALONG THE
FRONTAL BOUNDARY FROM CENTRAL KANSAS NORTHEAST THROUGH LAKE
SUPERIOR. A SERIES OF CONVECTIVE COMPLEXES DEVELOPED LATE LAST NIGHT
AND CONTINUE EARLY THIS MORNING. ACROSS NORTHERN IL/NORTHWEST IN
FLOW REMAINS SOUTHERLY WITH VERY MILD AND MOIST CONDS. DEW PTS HAVE
REMAINED IN THE LOW 60S OVERNIGHT...WHICH BASED ON CLIMATOLOGY IS A
FEW DEGREES WARMER THAN THE NORMAL HIGH TEMPS ON THIS DATE. IT
APPEARS THE DAY WILL START OFF WITH JUST SOME HIGH BASED CLOUDS
OVERHEAD...WHICH WILL ALLOW THE SFC TO WARM-UP EFFICIENTLY. WITH
SOME POTENTIAL FOR COMPRESSIONAL WARMING TO TAKE PLACE...TEMPS
ACROSS THE CWFA COULD EASILY PUSH BACK INTO THE UPR 70S TDY...AND
COULD SEE A FEW 80 DEG READINGS SOUTH OF A PONTIAC TO KANKAKEE LINE.
THEN THE LARGER FOCUS WILL BE ON THE PRECIP ARRIVAL...CONVECTION
CHANCES...AND FRONTAL PASSAGE. MINIMAL ADJUSTMENTS TO THE PREVIOUS
FORECAST...AS IT APPEARS THE FRONT SHUD ARRIVE ACROSS THE FAR
WESTERN CWFA ARND 18-21Z. LAPSE RATES STEEPEN...AND MUCAPE VALUES
ARE PROGGED TO APPROACH 1000J/KG THIS AFTN. THE BEST SHEAR SHUD PASS
WELL NORTH OF THE REGION...HOWEVER THE ENVIRONMENT OVERHEAD WILL
BECOME FAVORABLE FOR CONVECTION EARLY THIS AFTERNOON THROUGH EARLY
THIS EVENING FROM WEST TO EAST. HI-RES GUIDANCE WAS SUGGESTING THAT
PRECIP MAY BE MORE PLENTIFUL IMMEDIATELY BEHIND THE BNDRY. HAVE
MAINTAINED MENTION OF CONVECTION...HOWEVER HAVE TRIMMED BACK FROM
THE DEFINITE MENTION TO LIKELY. COULD EVEN SEE THIS BEING TRIMMED
BACK TO CHC THUNDER.
THEN THE BDNRY STEADILY MARCHES EAST ACROSS THE CWFA WITH WINDS
TURNING WEST/NORTHWEST BY 00Z...AND EXPECT THE FRONT TO HAVE PUSHED
EAST OF NORTHWEST IN AROUND 3Z FRI. THE CONVECTIVE THREAT WILL
RAPIDLY DIMINISH AS WELL AS THE DRY AIR STEADILY ARRIVES LATE THIS
AFTN. TEMPS WILL ALSO QUICKLY FALL POST FRONTAL...AND EXPECT BY 00Z
LOCATIONS WEST OF A PONTIAC TO CRYSTAL LAKE LINE WILL HAVE TEMPS
ALREADY IN THE UPR 40S. THEN THEY WILL CONTINUE TO RADIATE WITH LOWS
IN THE MID 30S ACROSS THE FAR NORTHWEST...AND LOW 40S FOR NORTHWEST
IN.
FRIDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL PUSH EAST ACROSS THE GREAT LAKES REGION
FRI...THEN BEGIN TO WEAKEN THROUGH THE SECOND HALF OF THE WEEKEND.
HOWEVER...DESPITE THE WEAKENING THE GENERAL THEME WILL FEATURE A
NORTHWEST FLOW. STRONG 500MB RIDGE WILL REMAIN IN PLACE ACROSS THE
CANADIAN MARITIME THROUGH THE WEEKEND...WHICH COULD SLOW THE
WEAKENING OF THE TROUGH OVER THE GREAT LAKES. ENSEMBLES ARE
DEMONSTRATING MINIMAL SPREAD AMONGST EACH MEMBER...THUS EXHIBITING A
HIGH CONFIDENCE.
SFC ANTI-CYCLONIC FLOW RAPIDLY PUSHES IN BEHIND THE COLD FRONT
FRI...AND SHUD AID IN A QUICK EROSION TO THE CLOUDS/PRECIP. 850MB
THERMAL TROUGH WILL STEADILY BUILD OVERHEAD FRI...WITH TEMPS MIDDAY
OF 0 TO -2 DEG C. AT THIS TIME IT APPEARS THE BULK OF FRI WILL
REMAIN DRY...HOWEVER CONDITIONS WILL BE STEADILY DEVELOPING FOR LAKE
EFFECT PRECIP GENERATION FRI EVE.
LAKE EFFECT PRECIP LOOKS PROBABLE FOR FRI NGT THRU SUN...AS FLOW
WILL GENERALLY BE NORTH. AT TIMES THE WINDS MAY VEER MORE TO THE
NORTHEAST...WHICH WOULD FAVOR A BUCKLE IN THE EXPECTED LAKE EFFECT
PRECIP COVERAGE AND PUSH IT OVER CHICAGO/WAUKEGAN. TEMPS DURING THE
DAY SHUD WARM ENOUGH TO KEEP PRECIP IN A LIQUID STATE OR SHRA. THEN
OVERNIGHT TEMPS ARE EXPECTED TO RADIATE INTO THE LOW/MID 30S...WHICH
MAY ALLOW FOR SOME WET SNOW TO BECOME MIXED WITH THE LGT RA.
OTHERWISE AREAS AWAY FROM LAKE MICHIGAN OR WEST OF I-355...SHOULD
SEE DRY WEATHER THRU THE FRI-SUN PERIODS AND PSBLY SUNNY SKIES.
AFTERNOON TEMPS SAT/SUN WILL STRUGGLE TO WARM WITH THE CONTINUED
FEED OF COLD AIR ADVECTION INTO THE AREA. BASED OFF OF THE PLUMES
AND GUIDANCE FOR THIS TIMEFRAME...MANY LOCATIONS MAY STRUGGLE TO
WARM BEYOND THE LOW/MID 40S. IT IS CONCEIVABLE THAT A FEW AREAS
NORTH OF I-88 COULD SEE TEMPS HOLD IN THE UPR 30S SAT.
MONDAY THROUGH WEDNESDAY...
THE FINAL FEW PERIODS OF THE EXTENDED BECOME VERY CHALLENGING. THE
AFOREMENTIONED HIGH LATITUDE RIDGING OVER THE CANADIAN MARITIME IS
PROGGED TO MAINTAIN ITSELF...AND GUIDANCE IS INDICATING THAT THE
TROUGH OVER THE GREAT LAKES WILL INITIALLY WEAKEN. THEN THIS TROUGH
WILL UNDERGO SOME ENHANCEMENT TUE/WED. THE OTHER CHALLENGE IS THE
TROPICAL SYSTEM IN THE WESTERN ATLANTIC...WHICH GUIDANCE HAS BEEN
SUGGESTING WILL SKIRT THE EAST COAST.
ONCE THE TROPICAL SYSTEM...SANDY...APPROACHES THE NEW ENGLAND AREA
GUIDANCE IS SUGGESTING IT WILL MERGE WITH THE TROUGH AND AMPLIFY.
THIS COULD RESULT IN A SLUG OF PRECIP PIVOTING WEST/SOUTHWEST ACROSS
LOWER MICHIGAN TUE AND ARRIVE ACROSS NORTHERN IL/NORTHWEST IN TUE
NGT/WED.
OVERALL THE TEMP OUTLOOK FOR THE EXTENDED PERIODS WILL REMAIN
COOL...WITH TEMPS GENERALLY IN THE MID/UPR 40S TO PSBLY LOW 50S
TUE/WED. OVERNIGHT LOWS WILL HINGE UPON CLOUD COVER...HOWEVER AT
THIS TIME ANTICIPATE TEMPS IN THE UPR 20S TO LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT...POSSIBLY BRIEF
LIFR. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015 AND LIKELY 010...LOW
TO MEDIUM CONFIDENCE IN LESS THAN 005. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
201 PM EDT THU OCT 25 2012
.AVIATION...
18Z TAFS...SOUTH WINDS OF 15 TO 25 KNOTS WITH GUSTS TO 30 KNOTS
WILL CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON WITH PEAK
MIXING. SOME DIMINISHMENT IN GUSTS INTO THE 20 TO 25 KNOT RANGE IS
EXPECTED THIS EVENING WITH LOSS OF DEEPER MIXING. SOME DRIER LOW
LEVEL AIR WHICH HAS ADVECTED IN FROM THE SOUTH WILL CAP ANY
CONVECTIVE ACTIVITY THIS AFTERNOON. TOWARD EVENING...LOW LEVEL
MOISTURE IS EXPECTED TO INCREASE AGAIN IN ADVANCE OF A COLD FRONT
ACROSS NORTHWEST ILLINOIS. A FEW ISOLATED SHOWERS OR STORMS ARE
POSSIBLE ALONG THE COLD FRONT...WITH A BETTER CHANCE OF MORE
WIDESPREAD RAIN SHOWERS DEVELOPING BEHIND THE FRONT LATE THIS
EVENING AT KSBN...AND FOR THE OVERNIGHT HOURS AT KFWA. BEST
ELEVATED INSTABILITY IS EXPECTED AT KSBN IN THE 03Z TO 06Z
TIMEFRAME...WHEN HAVE MAINTAINED VCTS MENTION. WINDS TO SHIFT
NORTHWEST BEHIND THE FRONT TONIGHT...WITH A PERIOD OF LOWER END
MVFR CONDITIONS EXPECTED BEHIND THE FRONT TONIGHT BEFORE CIGS MVFR
CIGS ARE EXPECTED TO IMPROVE ABOVE 2K FT FRIDAY MORNING AS DRIER
LOW LEVEL AIR ADVECTS IN. RAIN SHOWERS TO PERSIST AT KFWA THROUGH
LATE MORNING AS MID LEVEL FRONTAL ZONE IS SLOW TO PUSH OFF TO THE
EAST.
&&
.PREV DISCUSSION... /ISSUED 1132 AM EDT THU OCT 25 2012/
UPDATE...
ONLY TWEAK TO PREVIOUS GRIDS WAS TO ADJUST HOURLY TEMPERATURE
TRENDS MAINLY FOR THIS EVENING BASED ON UPSTREAM OBSERVATIONS IN
ASSOCIATION THE COLD FRONT PASSAGE. TRIED TO INCORPORATE A
NAM12/PREVIOUS FORECAST BLEND TO SHOW A BIT SHARPER OF A TEMP/DEW
POINT DROP OFF WITH FRONT. OTHERWISE...OTHER FORECAST ELEMENTS FOR
PERIOD ONE STILL APPEAR TO BE ON TRACK WITH HIGHS IN THE MID TO
UPPER 70S. HRRR HINTING AT SOME CONVECTIVE DEVELOPMENT ALONG THE
COLD FRONT ACROSS NORTHWEST INDIANA THIS EVENING...BUT STILL
SOMEWHAT SUSPICIOUS OF THIS SOLUTION WITH INSTABILITY EXPECTED TO
BE FAIRLY LIMITED UNTIL BECOMING MORE ELEVATED IN NATURE BEHIND THE
FRONT.
MARINE...
SOUTH WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH LATEST
MICHIGAN CITY OBSERVATIONS ALREADY INDICATING SOUTH GUSTS INTO
THE 25 TO 30 KNOT RANGE. CANNOT COMPLETELY RULE OUT A FEW GUSTS TO
NEAR GALES THIS AFTERNOON. OF GREATER CONCERN IS EARLY THIS
EVENING IN ASSOCIATION WITH THE FRONTAL PASSAGE. A NARROW BUT
STRONG CORRIDOR OF SURFACE PRESSURE RISES BEHIND THE FRONT SHOULD
INDUCE A PERIOD OF WEST GUSTS TO NEAR GALES THIS
EVENING...ESPECIALLY IN THE 00Z TO 04Z TIMEFRAME. HAVE HELD OFF ON
ANY UPGRADED HEADLINES AT THIS TIME...BUT WILL NEED TO CONSIDER AT
LEAST MENTION OF A FEW GUSTS TO GALE FORCE IN POSSIBLE NEARSHORE
FORECAST AMENDMENTS THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 703 AM EDT THU OCT 25 2012/
AVIATION.../12Z TAFS/
DVLPG SFC LOW ALONG STNRY FRONT OVER NE IA THIS MORNING WILL
DEEPEN/INTENSIFY AS IT LIFTS NE TODAY CAUSING STNRY FRONT TO SURGE
EASTWARD AS A CDFNT. STRONG SWLY WIND FIELD IN PLACE OVER THE AREA
ATTM WITH KIWX VWP INDICATING 40KT IN LOWEST GATE AT 2KFT. THESE
STRONG WINDS WILL MIX DOWN DURING THE DAY WITH SFC GUSTS 27-32KT
EXPECTED... HIGHEST AT SBN. OTRWS... VFR CONDITIONS THROUGH THE
DAY WITH JUST SCT CU.
CDFNT EXPECTED TO MOVE THROUGH SBN BY 04Z AND FWA BY 08Z FOLLOWED
BY A PERIOD OF SHOWERS WITH AVIATION CONDITIONS LOWERING AT LEAST
TO MVFR AND PSBLY IFR. INSTABILITY WILL BE LIMITED BUT PRBLY
SUFFICIENT FOR A FEW TSTMS AS FAR EAST AS NWRN INDIANA SO INCLUDED
VCTS IN SBN TAF. WNDSHFT ON CDFNT WILL BE ABRUPT FROM SW-NW WITH
STRONG LOW LEVEL CAA PROMOTING POST FRONTAL GUSTS THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 410 AM EDT THU OCT 25 2012/
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT...
THE FORECAST CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR A RECORD
HIGH TEMPERATURE AT SOUTH BEND TODAY AND THE TIMING OF A STRONG COLD
FRONT THURSDAY NIGHT ALONG WITH ASSOCIATED PRECIPITATION. HIGHS
WEDNESDAY WERE RATHER UNIFORM AROUND 78F DEGREES. ALTHOUGH A WARM
AND MOIST FLOW SHOULD CONTINUE FROM THE SOUTH AND SOUTHWEST TODAY...
SOMEWHAT COOLER AIR UNDER 925 MB SHOULD SPREAD INTO THE REGION IN
THE LOW LEVELS. HAVE KEPT HIGHS A LITTLE LOWER THAN YESTERDAY...
GENERALLY 75 TO 77 DEGREES...WHICH SHOULD KEEP THE TEMPERATURE BELOW
THE RECORD HIGH OF 80 DEGREES AT SOUTH BEND. A STRONG COLD FRONT WILL
MOVE ACROSS THE FORECAST AREA THURSDAY NIGHT. SOME QUESTION WHETHER
EARLY STORMS WILL BE SURFACE BASED...INCREASING THE RISK FOR SEVERE
STORMS WITH HIGH WINDS GIVEN MOMENTUM TRANSFER OF 50 TO 55 KNOTS IN
THE 925/850 MB LEVEL. HOWEVER..THE SUBSIDENCE INVERSION AND MID
LEVEL WARMING HAS INCREASED SIGNIFICANTLY UPSTREAM AS INDICATED ON
THE LINCOLN RAOB. CURRENT THINKING IS THAT ANY STORMS WILL BE
ELEVATED AND WILL BE POST FRONTAL...LIMITING GREATLY SEVERE WEATHER
POTENTIAL. GIVEN THE STRENGTH OF THE FRONT WHICH INCLUDES ABOUT A 25
DEGREE TEMPERATURE DROP IN THE FIRST 100 MILES...TEMPERATURES WILL
DROP TO BETWEEN 41F AND 43F OVER FAR SW AND WEST AREA. LASTLY...KEPT
LAKE EFFECT/LAKE ENHANCED SHOWERS OUT. WINDS VEER TOO FAR TO THE
NORTHEAST FRI NGT.
LONG TERM.../SAT-WED/
UPR LEVEL TROF OVER THE ROCKIES THIS MORNING WILL MOVE EAST TO THE
MS VALLEY AND DEEPEN A BIT BY SAT AS A SERIES OF MID LEVEL SHRTWVS
MOVE THROUGH THE BASE OF THE TROF. MODELS HAVE TRENDED A LITTLE
FASTER WITH SHRTWV EXPECTED TO MOVE THROUGH OUR AREA SAT... THUS
HAVE LOWERED POPS IN THIS PERIOD...ESPECIALLY IN THE AFTN.
MEDIUM RANGE MODELS HANDLING OF THE TROF MOVG INTO THE GRTLKS AND
ITS INTERACTION WITH WRN ATLANTIC HURRICANE SANDY HAS BEEN
ERRATIC... BUT THERE IS FAIR AGREEMENT ON 00Z RUNS THAT A RATHER
DEEP CLOSED/STACKED LOW WILL FORM OR MOVE INTO THE LWR GRTLKS EARLY
NEXT WEEK WITH IMPLICATION THAT WRN FRINGE OF ITS PRECIP SHIELD
AND/OR LAKE EFFECT OFF LAKE MICHIGAN WITH N-NW LOW LEVEL FLOW WOULD
IMPACT OUR AREA. STILL PLENTY OF UNCERTAINTY GIVEN POOR RUN-RUN
MODEL CONTINUITY AND CONSIDERABLE DIFFERENCES AMONG VARIOUS MODELS
ON DETAILS/EVOLUTION OF THE LOW... THUS BLEND OF MODELS AND PREVIOUS
FCST YIELDING JUST SLIGHT CHC POPS WAS FOLLOWED WITH ONLY COSMETIC
ADJUSTMENTS FOR DAYS6-7.
WITH LITTLE MOVEMENT AND GRADUAL DEEPENING OF UPR TROF OVER THE
GRTLKS THROUGH THE LONG TERM PERIOD... TEMPS SHOULD BE BLO NORMAL
WITH LITTLE DAILY CHANGE IN HIGHS/LOWS. FCST HIGHS GENERALLY IN THE
M-U40S AND LOWS IN THE L-M30S EACH DAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...MARSILI
UPDATE...MARSILI
MARINE...MARSILI
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1215 PM CDT THU OCT 25 2012
.UPDATED FOR 18Z AVIATION DISCUSSION...
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
COUPLE OF SNOW BANDS MOVING ACROSS MN PORTION OF THE AREA...WITH
LIGHT RAIN AFFECTING WESTERN WISCONSIN. INITIAL SNOW BAND OVER EAST
CENTRAL MN WILL MOVE EAST INTO WISCONSIN FOR THE AFTERNOON. WILL
SEE RAIN/SNOW MIX POSSIBLE CHANGING OVER TO ALL SNOW LATE AFTERNOON
BEFORE ENDING AT KEAU. SECOND PERSISTENT SNOW BAND MATCHES WELL
WITH HE MINUS 15C OMEGA FIELD AND THIS WILL LIFT NORTHEAST AND
WEAKEN THROUGH 20Z. SNOW WILL HAVE ENDED OVER THE FAR WESTERN AREA
AND SOON AT KSTC...WHERE SOME SLUSHY ACCUMULATION ON GRASSY AREAS
LIKELY OCCURRED. LESS THAN AN INCH THOUGH. CEILING IMPROVING A BIT
DIRECTLY BEHIND TROUGH...BUT SOME CONCERN OF MVFR CEILINGS
DEVELOPING BEHIND TROUGH LATER TONIGHT. SUBSIDENCE WILL BE STRONG
INITIALLY OR DIRECTLY BEHIND TROUGH...SO WILL CONTINUE TREND OF
REMAINING SCT OVERNIGHT. NORTHWEST WINDS WILL DIMINISH THIS EVENING
AND COULD BECOME GUSTY AGAIN OVER EASTERN AREAS AT LEAST INTO EARLY
AFTERNOON...BEFORE RIDGE BUILD IN ENOUGH. MAY SEE SOME BKN VFR
CEILINGS AGAIN...ESPECIALLY EAST IN THE LATE MORNING/AFTERNOON WITH
RESIDUAL MOISTURE AND SOME NEGATIVE CU RULES INDICATED.
KMSP...
IFR CONDITIONS FOR A FEW HOURS YET AS A COUPLE OF SNOW BANDS MOVE
THROUGH. MAY MIX WITH RAIN BETWEEN STRONGER VERTICAL MOTION.
SHOULD END BY 22Z WITH VFR CONDITIONS THEREAFTER. SOME CONCERN OF
LOWER CEILINGS MOVING IN AGAIN LATER TONIGHT FROM THE WEST...BUT
WILL REMAIN SCT FOR NOW. STRONG NORTHWEST WINDS WILL DIMINISH THIS
EVENING AND MAY BECOME GUSTY AGAIN INTO FRI AFTERNOON.
/OUTLOOK FOR KMSP/
FRI AFTN...VFR. WINDS WNW 10 G 20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...MVFR/VFR. CHC -RASN. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/DE
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
341 PM CDT Thu Oct 25 2012
.DISCUSSION...
Tonight through Saturday...
As precipitation exits the forecast area this afternoon, the main
focus for the short term will be temperatures, particularly tonight
and Friday night lows. Models don`t seem to have a good handle on
the widespread stratus building southward across portions of eastern
Nebraska and Iowa, which has the potential to strongly impact the
low temperature forecast tonight. Current water vapor imagery shows
some signs of developing subsidence behind the departing upper-level
jet streak in the eastern Dakotas; however, it is yet to be seen
whether this will translate to erosion of the low-level cloud field
this evening. Both the NAM and RAP do dry out first the midlevels
and eventually the low levels by 06z across southeast Nebraska and
into the forecast area, so have still continued a decreasing trend
in cloudiness tonight, leading to a cooler low temperature forecast
across the area. However, with some near-surface moisture remaining
and a more rapid temperature fall after 06z, do not think that a
freeze will be likely across the region even if clouds clear out
completely.
The setup on Friday night looks much more prototypical for a hard
freeze, with a 1032 mb surface high filtering into the central
Plains, pushing the surface ridge axis over northwest Missouri
shortly after midnight. Temperatures could easily drop into the mid
to upper 20`s across the majority of the region Saturday morning,
and would likely remain below freezing for several hours. If the
forecast remains on track, a freeze warning will be needed for areas
that have not already experienced a hard freeze this fall. The ridge
axis will remain over the region through early afternoon on
Saturday, keeping daytime temperatures 10 to 15 degrees below normal
in the upper 40s to lower 50s.
Laflin
Medium Range (Sunday through Thursday):
High forecast confidence this period as upper level flow remains
stagnant in the wake of a large downstream block formed by the
merging of an eastern trough and Hurricane Sandy into a potential
superstorm. This will maintain a steady northwest upper flow regime
over the regime which further amplify late in the period as
additional troughing builds into the Pacific Northwest.
All in all, precipitation chances are near zero through the period
and the effects of negative thermal advection vs. insolation will
generally offset each other. This will keep temperatures steady
through much of the week with highs in the low-mid 50s and lows in
the low-mid 30s.
Bookbinder
&&
.AVIATION...
For the 18Z TAFs, low level lift should shift eastward over the next
hour, ending the drizzle at the Kansas City terminals. Otherwise,
blustery conditions will continue with northwest winds gusting to
around 25 knots with widespread IFR ceilings through mid afternoon.
For ground crews, temps will hold steady in the mid 40s. Large scale
subsidence should overspread the terminals between 22 and 00Z,
allowing ceilings to lift to VFR and then scatter out.
Wind gusts should end by 01Z, with a northwest direction persisting
overnight as speeds decrease to 8-10 knots. Mainly clear skies
expected overnight into Friday morning.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
559 PM CDT THU OCT 25 2012
.AVIATION...
00Z TAF FOR KOMA...KOFK...KLNK
MODELS ARE HAVING A VERY DIFFICULT TIME WITH THE CLOUD FORECAST
OVERNIGHT. MOST MODELS WOULD INDC GENERALLY CLEAR SKIES WITH
DECREASING WINDS...BUT THIS APPEARS UNLIKELY GIVEN THE LARGE SC
DECK ACROSS...AND UPSTREAM FM THE AREA CURRENTLY. THUS WE WILL GO
WITH A PERSISTENCE FORECAST AT THIS TIME UNTIL MODEL FORECASTS
IMPROVE...OR CLEAR TRENDS IN OBSERVATION DATA DEVELOP. THUS WE
WILL HAVE MVFR CIGS AT ALL SITES THROUGH THE NIGHT. NORTHWEST
WINDS WILL BE DIMINISHING THROUGH THE NIGHT THOUGH AS THE PRESSURE
GRADIENT DECREASES.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 313 PM CDT THU OCT 25 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY. MAIN FORECAST PROBLEM IN
THE VERY NEAR TERM IS AN EXPANDING DECK OF STRATUS THAT NO MODEL
EXCEPT THE RAP SEEMS TO BE HANDLING ALL THAT WELL. THUS...HAVE
TRENDED CLOUD GRIDS UPWARD TONIGHT...BUT AM STILL THINKING THAT
SOME OF THIS MAY DISSIPATE THIS EVENING AS MORE ANTICYCLONIC FLOW
CONTINUES TO TAKE HOLD ACROSS THE REGION. IT WILL PROBABLY BE A
COLD NIGHT WITH LOWS IN THE 20S AS SKIES SCATTER OUT. GIVEN THE
RECENT RAINS...THERE COULD BE PATCHY FOG OVERNIGHT...BUT PROBABLY
NOT A BIG ENOUGH OF CONCERN TO ADD TO THE GRIDS.
HIGH PRESSURE CONTINUES TO MOVE OFF THE HIGH PLAINS ON FRIDAY WITH
NORTHWESTERLY FLOW AND SOME MID AND HIGH CLOUDS. HIGH PRESSURE
DRIFTS OVER THE FORECAST AREA FRIDAY EVENING WITH A RETURN FLOW
SETTING UP ON SATURDAY.
A NEW AREA OF LOW PRESSURE DEVELOPS ACROSS SOUTHWEST SOUTH DAKOTA
THROUGH THE DAY SATURDAY WHILE AN UPPER WAVE MOVES THROUGH THE
NORTHERN PLAINS. WARM AIR ADVECTION COULD RESULT IN A FEW SHOWERS
NEAR THE SD/NE BORDER SATURDAY AFTERNOON...THEN SLIDING EAST
SOUTHEAST DOWN THE MISSOURI RIVER VALLEY SATURDAY NIGHT. THE NAM
IS CONSIDERABLY WARMER...WHICH IS PROBABLY TOO WARM. BUT...THERE
COULD BE A FEW RAIN SHOWER OR EVEN A SNOW FLAKE MIXED IN MAINLY
NORTH OF OMAHA SATURDAY NIGHT. DRY WEATHER IS EXPECTED ON SUNDAY.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. MEDIUM RANGE MODELS
NOT SHOWING MUCH POTENTIAL FOR ANY PCPN THRU MOST OF NEXT WEEK.
OTHERWISE...LATEST GFS BLOCKING INDICES ADVERTISING UPSTREAM
BLOCKAGE DEVELOPING THRU DAY 7...ALLOWING FOR AMPLIFIED RIDGING
OVER THE ROCKIES/WRN HIGH PLAINS WITH 2 TROFS FLANKING THE CONUS.
THIS THEN LEADING TO THRUST OF COLD AIR DOWN THRU THE UPPER
MIDWEST/GREAT LAKES REGION REACHING ALL THE WAY DOWN TO THE SERN
STATES. AT THIS POINT THEN THE MAIN INTEREST IS HOW FAR WILL THE
WRN PERIPHERY OF CAA PUSH IT INTO THE CWA BEFORE AFOREMENTIONED
ROCKIES/WRN HIGH PLAINS RIDGE BUILDS IN. COMPARISON OF 1000-500MB
THKNS DAYS 5-7...ECM DETERMINIST PROGS CLEARLY SHOW IT TO BE THE
WARMER OF THE TWO. THIS ALSO REFLECTED THRU WARMER ECM MOS MAX/MIN
TEMPS RELATIVE TO THE MEX. GOING FCST APPEAR TO BE IN ACCORDANCE
WITH THE WARMER ECM SOLUTION...THUS SEE NO REASON TO MAKE ANY
CHANGE DEPICTING WARMING TREND IN THE EXTEND PDS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
313 PM CDT THU OCT 25 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY. MAIN FORECAST PROBLEM IN
THE VERY NEAR TERM IS AN EXPANDING DECK OF STRATUS THAT NO MODEL
EXCEPT THE RAP SEEMS TO BE HANDLING ALL THAT WELL. THUS...HAVE
TRENDED CLOUD GRIDS UPWARD TONIGHT...BUT AM STILL THINKING THAT
SOME OF THIS MAY DISSIPATE THIS EVENING AS MORE ANTICYCLONIC FLOW
CONTINUES TO TAKE HOLD ACROSS THE REGION. IT WILL PROBABLY BE A
COLD NIGHT WITH LOWS IN THE 20S AS SKIES SCATTER OUT. GIVEN THE
RECENT RAINS...THERE COULD BE PATCHY FOG OVERNIGHT...BUT PROBABLY
NOT A BIG ENOUGH OF CONCERN TO ADD TO THE GRIDS.
HIGH PRESSURE CONTINUES TO MOVE OFF THE HIGH PLAINS ON FRIDAY WITH
NORTHWESTERLY FLOW AND SOME MID AND HIGH CLOUDS. HIGH PRESSURE
DRIFTS OVER THE FORECAST AREA FRIDAY EVENING WITH A RETURN FLOW
SETTING UP ON SATURDAY.
A NEW AREA OF LOW PRESSURE DEVELOPS ACROSS SOUTHWEST SOUTH DAKOTA
THROUGH THE DAY SATURDAY WHILE AN UPPER WAVE MOVES THROUGH THE
NORTHERN PLAINS. WARM AIR ADVECTION COULD RESULT IN A FEW SHOWERS
NEAR THE SD/NE BORDER SATURDAY AFTERNOON...THEN SLIDING EAST
SOUTHEAST DOWN THE MISSOURI RIVER VALLEY SATURDAY NIGHT. THE NAM
IS CONSIDERABLY WARMER...WHICH IS PROBABLY TOO WARM. BUT...THERE
COULD BE A FEW RAIN SHOWER OR EVEN A SNOW FLAKE MIXED IN MAINLY
NORTH OF OMAHA SATURDAY NIGHT. DRY WEATHER IS EXPECTED ON SUNDAY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. MEDIUM RANGE MODELS
NOT SHOWING MUCH POTENTIAL FOR ANY PCPN THRU MOST OF NEXT WEEK.
OTHERWISE...LATEST GFS BLOCKING INDICES ADVERTISING UPSTREAM
BLOCKAGE DEVELOPING THRU DAY 7...ALLOWING FOR AMPLIFIED RIDGING
OVER THE ROCKIES/WRN HIGH PLAINS WITH 2 TROFS FLANKING THE CONUS.
THIS THEN LEADING TO THRUST OF COLD AIR DOWN THRU THE UPPER
MIDWEST/GREAT LAKES REGION REACHING ALL THE WAY DOWN TO THE SERN
STATES. AT THIS POINT THEN THE MAIN INTEREST IS HOW FAR WILL THE
WRN PERIPHERY OF CAA PUSH IT INTO THE CWA BEFORE AFOREMENTIONED
ROCKIES/WRN HIGH PLAINS RIDGE BUILDS IN. COMPARISON OF 1000-500MB
THKNS DAYS 5-7...ECM DETERMINIST PROGS CLEARLY SHOW IT TO BE THE
WARMER OF THE TWO. THIS ALSO REFLECTED THRU WARMER ECM MOS MAX/MIN
TEMPS RELATIVE TO THE MEX. GOING FCST APPEAR TO BE IN ACCORDANCE
WITH THE WARMER ECM SOLUTION...THUS SEE NO REASON TO MAKE ANY
CHANGE DEPICTING WARMING TREND IN THE EXTEND PDS.
DEE
&&
.AVIATION...18Z TAFS FOR KOMA...KLNK...AND KOFK.
EXTENSIVE STRATUS DECK CONTINUES TO SPILL SOUTHEAST FROM THE
DAKOTAS. WILL GO WITH MVFR CONDITIONS THROUGH THE ENTIRE TAF PERIOD.
NO MODEL DATA HAS A GOOD HANDLE ON CURRENT CLOUDS AND SO HAVE BASED
THE TAF FORECAST ON CURRENT TRENDS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
257 PM CDT THU OCT 25 2012
.DISCUSSION.../ISSUED AT 257 PM CDT/
PRECIPITATION HAS ENDED ACROSS THE ENTIRE CWA LATE THIS
AFTERNOON...LEAVING BEHIND A BROAD AREA OF STRATUS OVER THE REGION.
THESE CLOUDS WILL BE THE MAIN CHALLENGE FOR THE SHORTER TERM
PERIOD...WITH MODELS NOT HANDLING THE LOW CLOUDS WELL. RUC LOOKS TO
BE THE BEST WITH THE LOW LEVEL RH FIELD...AND KEEPS THE STRATUS OVER
OUR AREA THROUGH AT LEAST THE EARLY EVENING. AS HIGH PRESSURE BUILDS
INTO THE REGION FROM THE WEST OVERNIGHT...A LESSENING SURFACE
GRADIENT WILL ALLOW WINDS TO COME DOWN BY EARLY EVENING. WENT ON THE
LOW SIDE OF GUIDANCE WITH REGARD TO LOWS TONIGHT...GENERALLY UPPER
TEENS TO LOWER 20S...WITH RELATIVELY LIGHT WINDS...SOME POSSIBLE
SNOW COVER IN SOME AREAS...AND BANKING ON CLOUDS BEGINNING TO BREAK
UP OVERNIGHT. IF CLOUDS PERSIST...IT MAY NOT GET AS COLD AS
CURRENTLY IN THE FORECAST. ANOTHER CHALLENGE WILL BE WHETHER ANY FOG
IS ABLE TO DEVELOP TOWARD FRIDAY MORNING. WHILE NOT AN IDEAL SET UP
WITH LIGHT NORTHWESTERLY WINDS...THINKING IS IF CLOUDS CLEAR OUT AND
WINDS DROP OFF...IN CONJUNCTION WITH ABUNDANT NEAR SURFACE MOISTURE
FROM RECENT RAINFALL/SNOW MELT...FOG WILL DEVELOP IN SOME AREAS. DID
NOT INCLUDE IN THE FORECAST AT THIS POINT...HOWEVER EVENING SHIFT
MAY UPDATE IF IT LOOKS MORE LIKELY.
FRIDAY LOOKS TO BE ANOTHER COOL DAY WITH THE CENTER OF THE HIGH
PRESSURE SLIDING OVERHEAD BY AFTERNOON. THERMAL PROFILES ACTUALLY
COOL A BIT OVER TODAY...THOUGH MODELS HINT AT SOME MID CLOUDS
STREAMING INTO OUR WEST...THERE WILL GENERALLY BE MORE SUN THAN
TODAY WITH HIGHS REACHING INTO UPPER 30S TO LOWER 40S. /JM
FRIDAY NIGHT WILL SEE A WEAK RIDGE OF HIGH PRESSURE MOVE ACROSS THE
AREA...LOCATED NEAR NORTHWEST IOWA BY 12Z SATURDAY. TO THE WEST
SOUTHERLY FLOW AS WELL AS CLOUD COVER WILL INCREASE AS A SHORTWAVE
MOVES INTO THE NORTHERN AND CENTRAL ROCKIES. THIS WILL MAKE FOR
TRICKY LOW TEMPERATURES FORECASTING. WILL LEAN A LITTLE MORE TOWARD
THE CONSMOS IN NORTHWEST IA WHERE WINDS WILL BE LIGHTEST AND CLOSER
TO THE CONSRAW IN CENTRAL SD WHERE WINDS AND CLOUDS WILL LIKELY KEEP
TEMPERATURES A LITTLE MILDER.
LATE SATURDAY AFTERNOON AND SATURDAY NIGHT WILL PROVE TO BE THE NEXT
CHANCE FOR PRECIPITATION. THERE ARE SOME DIFFERENCES AMONGST THE
MODELS LEADING TOWARDS LOWER CONFIDENCE IN A SOLUTION. THE GFS IS
THE MOST BOISTEROUS LEAVING COLDER AIR IN PLACE AND BRINGING HEAVIER
QPF AMOUNTS TO THE NORTHERN CWA. THE NAM IS MUCH WARMER IN THE LOWER
LEVELS THAN THE GFS WHILE THE ECMWF IS A LITTLE BIT WARMER. BOTH
MODELS WOULD LIKELY SUPPORT SNOW HOWEVER AS THE LOW LEVELS ARE
FAIRLY DRY AND WOULD EASILY SWITCH TO SNOW. SREF SOUNDINGS ALL OVER
THE PLACE DURING THIS TIME FRAME AS WELL. DYNAMICALLY THERE IS
SUPPORT FOR SOME PRECIPITATION WITH ICE PROCESSES LIKELY AS THE -12
TO -18 DEGREE C LAYER IS FROM ABOUT 9000 TO 15000 FEET AND THERE
WOULD LIKELY BE A LITTLE BIT OF FRONTAL FORCING AROUND THIS LAYER.
HOWEVER...FRONTAL FORCING WEAK AND WAVE NOT VERY WELL DEFINED SO
BELIEVE THAT THE NAM AND GFS OVERDOING QPF AMOUNTS IN THE THIRD TO
HALF AN INCH RANGE. THE MUCH STRONGER AND BETTER DEFINED SYSTEM THAT
JUST MOVED THROUGH TODAY BARELY PRODUCED AMOUNTS THIS HIGH SO WILL
LOWER BY ABOUT TWO THIRDS. WILL INCREASE POPS INTO THE LIKELY
CATEGORY SATURDAY NIGHT ALONG THE HIGHWAY 14 CORRIDOR HOWEVER AS
SOME MEASURABLE SNOWFALL LOOKS POSSIBLE. WILL KEEP HIGHS THE COOLEST
OVER THE NORTHERN CWA WHERE A MIX OF POTENTIALLY THICKER CLOUD COVER
AND COOLER LOW LEVEL THERMAL FIELD WHILE THE SOUTH COULD MIX JUST A
BIT WITH A SOUTHERLY COMPONENT. LOOKING AT LOWER 40S NORTH TO NEAR
50 SOUTH.
MOST OF THE SNOWFALL WILL BE EAST OF THE AREA ON SUNDAY MORNING WITH
GRADUALLY CLEARING SKIES THROUGH THE DAY. WINDS WILL NOT BE VERY
STRONG SO COOL HIGH TEMPERATURES IN THE MID 40S TO AROUND 50 WILL
NOT FEEL TOO BAD.
IN THE LATTER PERIODS(MON/THU)...NOT MUCH CHANGE IN THIS PERIOD AS
MODELS CONTINUE TO CONVERGE ON THE ECMWF SOLUTION. WHICH HAS BEEN
VERY CONSISTENT THIS WEEK. BASICALLY LOOKING AT A RIDGE OF HIGH
PRESSURE AT THE SURFACE VARYING FROM ABOUT THE BIG SIOUX RIVER
VALLEY EAST INTO WESTERN MINNESOTA. THIS WILL KEEP COOL CONDITIONS
IN PLACE BUT WINDS WILL LIKELY REMAIN FAIRLY CALM. THE WESTERN CWA
WILL SEE THE BEST CHANCE FOR ABOVE NORMAL TEMPERATURES WHILE
SOUTHWEST MINNESOTA WILL HAVE THE BEST CHANCE AT NORMAL TO A BIT
BELOW NORMAL TEMPERATURES. /08
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
WITH MODEL DIFFERENCES...CONFIDENCE RATHER LOW WITH REGARD TO HOW
QUICKLY STRATUS DEPARTS THE REGION...BUT THINK CLOUDS WILL BEGIN TO
LIFT A BIT BY LATE THIS AFTERNOON. BY TONIGHT...NORTHWESTERLY WINDS
WILL BECOME RELATIVELY LIGHT. DEPENDENT ON ANY REMAINING CLOUD COVER
AND HOW LIGHT WINDS BECOME OVERNIGHT...WILL BE THE POSSIBILITY OF
FOG FORMATION OVER PORTIONS OF THE AREA VERY LATE TONIGHT INTO
FRIDAY MORNING WITH ABUNDANT NEAR SURFACE MOISTURE WITH MELTING SNOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$