Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/08/12


AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
214 PM EST Tue Nov 6 2012 .NEAR TERM [Through Tonight]... The 18z CONUS NAM/Regional RAP analysis continued to depict a highly amplified pattern across the country with the western half dominated by deep layer ridging, and a broad trough across the east. Embedded within the eastern U.S. trough were several disturbances, most notably the potent shortwave moving out of the Southeast into the Mid-Atlantic. This disturbance is forecast to be responsible for the Nor`easter which is likely to impact the Northeast beginning tomorrow. Further upstream, two more impulses are noted, one in the Middle Mississippi Valley, and another in the Upper Valley. These will impact (minimally) our region both tonight and tomorrow. Wrap around moisture from the surface feature generated by last nights upper level disturbance, combined with drying mid-levels are responsible for the low clouds being experienced mainly across our SE AL and SW GA counties. In many locations under the solid cloud deck, temperatures have failed to reach the 60s. The clouds will continue to scatter through the afternoon and allow more-and-more sunlight to help warm things up. Updated afternoon highs to show near 60 degrees in these locations, up to the lower 70s across portions of south central Georgia and north Florida. Overnight, the focus shifts back to the upper levels as the aforementioned energy over the Mississippi Valley dives into the Southeast. There may be just enough moisture with this shortwave to generate some light showers overnight, more likely across AL and GA rather than FL. There may also be a fog/low ceiling mixture across AL and GA, possibly spilling into inland north Florida as well. Overnight lows are expected to fall into the lower to middle 40s area wide. && .SHORT TERM [Wednesday Through Friday]... The 500 mb height pattern will change quickly from Wednesday to Friday as a broad, fairly deep trough over the Southeast (on Wednesday) gets replaced by a deep layer ridge by Friday. It appears there will be one last potent short wave rounding the base of this broader trough Wednesday afternoon and evening. Like its predecessors, this upper level disturbance will be rather strong, but all of the latest NWP guidance indicates a lack of deep layer moisture. There is an old saying that if the dynamics are there, the moisture will be too, meaning that vigorous systems like this can find ways to "squeeze" seemingly small amounts of moisture out of the atmosphere, so we added a slight PoP to our forecast for our GA zones. Once this disturbance passes by, there will be fair weather. Temperatures will be seasonally cool Wednesday through Friday morning with highs in the mid to upper 60s, and lows in the lower 40s inland (away from the cities) and upper 40s at the beaches. Highs Friday afternoon will return to the mid 70s. && .LONG TERM [Friday Night through Tuesday]... Deep layer ridging will the dominant weather feature this weekend into early next week, with fair weather. High temperatures will be above average (mid to upper 70s). Lows will begin the weekend a bit below average (lower to mid 40s inland), then warm to above average by Monday and Tuesday (mid 50s). A cold front will move east across the region Monday night and Tuesday, bringing with it a chance of rain. && .AVIATION [Beginning 19Z Tuesday]... Expect cloud cover to decrease for KECP and KTLH throughout the rest of today as dry air and mixing help thin out the cloud cover moving in from the Northwest. While sites like KABY and KDHN will continue to see BKN to SCT conditions with lower ceilings. For overnight expect a mix of light fog and low ceilings to effect most sites except KECP. This is due to the incoming shortwave in northern Georgia sending some cloud cover and moisture into our CWA. By 13Z most sites will clear out to VFR. && .MARINE... Conditions will be slightly below "Exercise caution" tonight, then pick up to near caution levels Wednesday or Wednesday night. Conditions will improve quickly Thursday afternoon. && .FIRE WEATHER... Although we will be relatively dry over the next couple of days, relative humidity values will likely be high enough to quell the need for any advisories. However, once deep layer ridging takes hold by Friday, there will likely be fire weather concerns that will need to be addressed. && .HYDROLOGY... The upcoming rainfall for tonight and Tuesday is not expected to be heavy enough to create flooding concerns, and there are no significant river rises expected over the next week across the area. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 43 67 41 67 40 / 10 0 0 0 0 Panama City 49 68 46 67 47 / 10 0 0 0 0 Dothan 42 65 40 67 39 / 10 10 0 0 0 Albany 43 64 40 68 38 / 20 20 10 0 0 Valdosta 44 63 41 66 39 / 10 10 10 0 0 Cross City 45 67 41 69 40 / 10 0 0 0 0 Apalachicola 47 67 45 65 48 / 10 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM/AVIATION/FIRE WX...Harrigan/Hersey SHORT TERM/LONG TERM/MARINE/HYDROLOGY...Fournier
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1007 AM EST Tue Nov 6 2012 .NEAR TERM [Through Tonight]... The 12z CONUS NAM/Regional RAP analysis depicted a highly amplified pattern across the country with the western half dominated by deep layer ridging, and a broad trough across the east. Embedded within the eastern U.S. trough were several disturbances, most notably the potent shortwave centered over the Southeast. It was this disturbance that initiated widespread rain and isolated thunderstorms overnight. As of 14z the shortwave had made enough eastward progress to push the surface front through the area. Thus, land areas across our CWA are rain free, with only isolated showers remaining well offshore. The main concern this morning has to do with timing the dissipation of fog that developed in the clear region between the passing front and advancing low ceilings, as well as timing the dissipation of the ceilings themselves. The current thinking is that the remaining fog will dissipate within the next hour, while the ceilings will slowly scatter through the morning, making little eastward progress. The trend in ceilings will have to be monitored closely as any prolonged ceilings could have a substantial impact on afternoon high temperatures. For now, expect a north to south temperature gradient with high in the lower 60s across southern GA and AL, up to near 70 degrees across coastal portions of North Florida. Overnight, the focus shifts back to the upper levels as another piece of energy dives south through the Mississippi Valley, then into the Southeast. There may be just enough moisture with this shortwave to generate some light showers overnight, more likely across AL and GA rather than FL. There may also be a fog/low ceiling mixture across AL and GA, possibly spilling into inland north Florida as well. Overnight lows are expected to fall into the lower to middle 40s area wide. && .SHORT TERM [Wednesday Through Thursday]... The axis of the upper trough will swing to our east on Thursday with deep layer ridging approaching the CWA from the west. Temps on Wednesday and Thursday will only climb to the mid to upper 60s. The coldest temps are forecast for Wednesday night where all inland areas should see upper 30s with mid 40s near the coast by daybreak Thursday. && .LONG TERM [Thursday Night through next Monday]... Deep layer ridging will continue to build in from the west and by late in the week temperatures are expected to moderate back to near/above normal levels. Dry conditions are expected through next weekend before rain chances increase ahead of a cold front early next week. && .AVIATION [Beginning 14Z Tuesday]... MVFR ceilings on the backside of a passing front will slowly scatter through the morning. Expect these ceilings to at least rise to VFR levels by around 18z. A low ceiling/fog mix is possible once again tomorrow morning, however, this threat will be looked at more closely when the latest data arrives before the next full TAF issuance. && .MARINE... Winds and seas will increase today behind a cold front that passed overnight. Cautionary level winds will develop today and continue into Thursday morning. Winds will subside below headline criteria from Thursday through Friday night. High pressure will strengthen northeast of the area by the weekend which will bring a return of cautionary level winds by Saturday afternoon. && .FIRE WEATHER... Showers early this morning, will exit the region to the east by midday with drier air moving in from the west. However, even with the drier airmass, lower temperatures will keep humidity values above critical levels. The next chance for red flag conditions will be late in the week as the airmass remains dry, and temperatures begin to warm. && .HYDROLOGY... The upcoming rainfall for tonight and Tuesday is not expected to be heavy enough to create flooding concerns, and there are no significant river rises expected over the next week across the area. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 70 44 67 39 68 / 10 10 0 0 0 Panama City 68 48 69 44 67 / 10 0 0 0 0 Dothan 64 43 66 39 67 / 10 0 0 0 0 Albany 63 40 65 39 67 / 10 10 0 0 0 Valdosta 67 41 64 39 66 / 20 10 0 0 0 Cross City 71 44 67 38 69 / 30 10 0 0 0 Apalachicola 69 46 68 42 66 / 10 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Harrigan SHORT TERM...Harrigan/Barry LONG TERM...Camp AVIATION...Harrigan MARINE...Barry FIRE WEATHER...Camp HYDROLOGY...Barry
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
959 PM EST WED NOV 7 2012 ...FROST LIKELY INLAND TONIGHT... .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST TONIGHT INTO FRIDAY THEN PERSIST OVER THE WEEKEND. A WEAK COASTAL TROUGH MAY FORM NEARBY EARLY NEXT WEEK...AS THE HIGH BEGINS TO SHIFT EAST. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... THE MID-LEVEL CLOUD DECK THAT HAS BEEN IMPACTING LOCATIONS SOUTH OF I-16 THIS EVENING IS BEGINNING TO ERODE FROM NORTHWEST- SOUTHEAST AS THE RESPONSIBLE LOBE OF CHANNELED VORTICITY SHIFTS SOUTH AND EAST. KCLX CLEAR AIR REFLECTIVITY SCANS ARE STILL PICKING UP SOME VERY LIGHT SPRINKLES OVER COASTAL MCINTOSH COUNTY...BUT THESE WILL SHIFT OFFSHORE SHORTLY. DRY CONDITIONS WILL DOMINATE FOR THE REST OF THE NIGHT. THE POTENTIAL FOR FROST CONDITIONS REMAINS THE PRIMARY FORECAST ISSUE FOR THE OVERNIGHT HOURS. THE BOUNDARY LAYER HAS ESSENTIALLY DECOUPLED FOR ALL BUT THE COASTAL COUNTIES THIS EVENING WITH A STRONG NOCTURNAL INVERSION NOTED ON REGIONAL RAP FORECAST SOUNDINGS. ALTHOUGH WINDS ATOP THE BOUNDARY LAYER ARE FORECAST TO INCREASE OVERNIGHT WITH THE APPROACH OF A SECONDARY VORTICITY OVER SOUTHWEST VIRGINIA...MODEL SOUNDINGS SUGGEST THE NOCTURNAL INVERSION WILL LIKELY REMAIN STRONG ENOUGH TO PREVENT A FULL RECOUPLING OF THE BOUNDARY LAYER. BUFKIT MIXING PROFILES ONLY SUPPORT 5 KT OF MIXED LAYER WIND THROUGH SUNRISE. THE COMBINATION OF LIGHT WINDS AND CLEAR SKIES WILL PROMOTE STRONG RADIATIONAL COOLING FOR MANY AREAS TONIGHT. SHOULD SEE LOWS DROP INTO MID 30S WELL INLAND WITH LOWER 40S NEAR THE COAST. COULD EVEN SEE A FEW AREAS APPROACH THE FREEZING MARK IN SOME OF THE NORMALLY COLDER SPOTS SUCH AS ALLENDALE...ROCKY FORD AND JAMESTOWN...BUT THE SITUATION LOOKS TOO MARGINAL FOR A FREEZE WARNING. THERE WILL BE A RISK FOR FROST TONIGHT. CONDITIONS WILL BE THE MOST FAVORABLE FOR SCATTERED FROST ROUGHLY ALONG AND NORTH OF AN ALLENDALE-HAMPTON-WALTERBORO-SUMMERVILLE-JAMESTOWN LINE. A FROST ADVISORY HAS BEEN ISSUED FOR THESE AREAS FROM 1 AM-8 AM THURSDAY. NORTHERLY WINDS OVER LAKE MOULTRIE SHOULD MITIGATE THE RISK FOR FROST SOMEWHAT JUST DOWNWIND OF THE LAKE...WHICH INCLUDES MONCKS CORNER. THERE WILL BE A CHANCE FOR PATCHY FROST AS FAR EAST AND SOUTH AS NORTH CHARLESTON-JACKSONBORO-GARDENS CORNER-POOLER- HINESVILLE AND LUDOWICI. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... SURFACE HIGH PRESSURE WILL SHIFT EAST ACROSS THE AREA THIS PERIOD WITH DRY AND UNSEASONABLY COOL CONDITIONS EXPECTED...ESPECIALLY THROUGH FRIDAY NIGHT. THE BIGGEST CONCERN WILL BE OVERNIGHT LOW TEMPERATURES IN THE MID TO UPPER 30S WHICH WILL PROMOTE SOME FROST DEVELOPMENT ACROSS THE COOLER SHELTERED INLAND LOCALES. THUS...A FROST ADVISORY MAY EVENTUALLY BE NEEDED. LESS LIKELY IS THAT A FEW SPOTS COULD DIP INTO THE LOWER 30S...WHICH COULD NECESSITATE A FREEZE WATCH AND/OR WARNING. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... OVERALL MODEL AGREEMENT IN THE LONG TERM PERIOD IS PRETTY GOOD. THE UPPER RIDGE WILL HANG ON ALONG THE EASTERN SEABOARD THROUGH MONDAY BEFORE BEING ERODED AWAY FROM THE WEST BY A DE-AMPLIFYING TROF MOVING ACROSS THE GREAT LAKES INTO TUESDAY. AT THE SURFACE...HIGH PRESSURE LOCATED TO THE NORTHEAST WILL CONTINUE TO EXTEND INTO THE REGION THROUGH MONDAY. THE MODELS HINT AT THE DEVELOPMENT OF A WEAK SURFACE TROF AND A MORE ONSHORE EASTERLY FLOW. THE MODEL PRECIP RESPONSE IS QUITE MUTED...AND THE MAIN AFFECT OF THE INCREASINGLY ONSHORE FLOW WILL BE MORE LOW LEVEL MOISTURE AND CLOUD COVER. ONCE THE RIDGE FINALLY BREAKS DOWN AND THE HIGH RETREATS FURTHER TO THE NORTHEAST...THE MODELS DEPICT A COLD FRONT APPROACHING THE AREA FROM THE WEST MONDAY NIGHT INTO TUESDAY. GIVEN THE WEAKENING NATURE OF THE FRONT AND THE UPPER TROF...I HAVE KEPT POPS IN THE LOW END CHANCE TO SLIGHT CHANCE RANGE AT THE END OF THE FORECAST PERIOD. TEMPS WILL GENERALLY RUN AT OR JUST ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... VFR. EXTENDED AVIATION OUTLOOK...NO CONCERNS. && .MARINE... NW FLOW TO CONTINUE THROUGH TONIGHT WITH A SLIGHT INCREASE LATE THIS EVENING AND OVERNIGHT AS A LOW-LEVEL JET SHIFTS THROUGH. ALL WATERS SHOULD STAY BELOW ADVISORY CRITERIA ALTHOUGH A FEW BRIEF GUSTS TO 25 KT ARE POSSIBLE OVER FAR OUTER PORTIONS OF THE OFFSHORE GA WATERS. THURSDAY THROUGH MONDAY...RATHER QUIET MARINE CONDITIONS EXPECTED THIS PERIOD...ESPECIALLY AFTER THURSDAY MORNING...WITH WINDS MAINLY 15 KT OR LESS AS HIGH PRESSURE SHIFTS FROM WEST TO EAST ACROSS THE AREA. A TROUGH OF LOW PRESSURE MAY DEVELOP OFF THE COAST EARLY NEXT WEEK AS THE HIGH MOVES OFFSHORE BUT THIS FEATURE WOULD GENERALLY AFFECT WIND DIRECTIONS MORE SO THAN SPEEDS. SEAS WILL REMAIN 2-3 FT OR LESS INTO SUNDAY BEFORE BUILDING EARLY NEXT WEEK GIVEN THE INCREASING EAST NORTHEAST SWELL. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FROST ADVISORY FROM 1 AM TO 8 AM EST THURSDAY FOR SCZ040- 042>045. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...ST SHORT TERM...RJB LONG TERM...BSH AVIATION...ST MARINE...ST
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
541 PM CST WED NOV 7 2012 .AVIATION... HIGH PRESSURE CENTERED OVER THE MISSISSIPPI RIVER IN EASTERN IA AND NORTHWEST IL WILL DRIFT SOUTHEAST INTO THE LOWER OHIO RIVER VALLEY BY THURSDAY MORNING. A LARGE AREA OF CLOUDS WITH CIGS FROM 25HND TO 35HND FT EXTENDS WEST INTO CENTRAL IA EARLY THIS EVENING. THE CLOUDS ARE EXPECTED TO SLOWLY CLEAR FROM WEST TO EAST THIS EVENING...HOWEVER THERE IS SOME UNCERTAINTY ON THE TIMING AND THERE IS SOME INDICATION THAT THE CLEARING MAY NOT OCCUR NEAR THE MISSISSIPPI RIVER UNTIL AFTER MIDNIGHT. ONCE THE CLOUDS CLEAR SOME FOG IS EXPECTED TO DEVELOP BUT HIGH CLOUDS/CIRRUS STREAMING IN FROM THE NORTHERN PLAINS SHOULD PROVIDE ENOUGH CLOUD COVER LATE TONIGHT TO KEEP VISIBILITIES IN THE 3-5SM RANGE. FOR THURSDAY VFR CONDITIONS ARE EXPECTED WITH SOUTH WINDS INCREASING TO 10 TO 20KTS BY MID MORNING AND CONTINUING THROUGH THE AFTERNOON. DLF && .PREV DISCUSSION... /ISSUED 259 PM CST WED NOV 7 2012/ SYNOPSIS... LATEST SFC ANALYSIS WAS INDICATING RIDGE AXIS CONTINUING TO SLIDE ACRS THE EASTERN PLAINS INTO THE WESTERN GRT LKS. CENTRAL TO NORTHERN PLAINS RIFE WITH PRESSURE FALLS AND LLVL RETURN FLOW... TEMPS IN THE 50S AND 60S. 12Z UPPER AIR ANALYSIS AND MID/HIGH LEVEL MOISTURE FLOW PATTERNS ON CURRENT WATER VAPOR LOOP SHOW PREVIOUSLY PRONOUNCED UPPER RIDGE ACRS THE ROCKIES GETTING PRESSED EASTWARD ACRS THE NORTHERN PLAINS BY SURGE OF PACIFIC NW UPPER JET ENERGY. OTHER UPPER JET MAX OVER THE ARE THIS MORNING STARTING TO DEPART OFF TO THE SOUTHEAST INTO EAST COAST L/W TROF BASE. SHORT TERM...TONIGHT AND THURSDAY... TONIGHT...MAIN CHALLENGE TONIGHT CONTINUES TO BE WHAT WILL HAPPEN TO ONGOING CLOUD DECK ALIGNED ACRS MUCH OF THE UPPER TO MID MS RVR VALLEY REGIONS. DEPARTING UPPER JET TO THE SE AND ARRIVAL OF UPSTREAM RIDGE GETTING PRESSED ACRS THE AREA WILL CONTINUE TO ENHANCE ONGOING SUBSIDENCE REGIME WHICH NORMALLY WOULD MEAN A CLOUD DECAY/CLEAR OUT. BUT FCST SOUNDINGS AND UPPER AIR SOUNDINGS SUGGEST TRAPPING INVERSION ALOFT TO GET ENHANCED BY THE SAME PROCESSES THIS EVENING AND INTO THE OVERNIGHT...WHICH COULD TRAP THE CLOUD COVER AND LIMIT CLEAR OUT TRENDS INTO EARLY THU MORNING. LATEST RAP RUNS IN HANDLING MOISTURE IN THE H95-H85 MB LAYER ALSO POINT TO THE LOW CLOUDS GETTING TRAPPED ALONG AND EAST OF THE MS RVR THROUGH AT LEAST MIDNIGHT BEFORE SOME CLEARING PUSH INCREASE FROM THE WEST AFTER 09Z TONIGHT. WEST OF THE MS RVR...EXPECT PREVIOUS CLEARING HOLES THAT DIURNALLY FILLED WITH CUMULUS TO CLEAR OUT AGAIN AFTER SUNSET...MAKING FOR A PATCHY CLEARING PATTERN ACRS THE WESTERN HALF OF THE CWA AS THE EVENING PROGRESSES. WILL PLAY THE CLOUDS A BIT MORE PESSIMISTIC IN THE FCST AND HANG THEM ON ESPECIALLY ACRS THE EASTERN HALF OF THE CWA WELL PAST MIDNIGHT...WITH SOME CLEARING TRENDS TOWARD SUNRISE THU MORNING. RIDGE-RIDING CI WILL ALSO SPILL DOWN ACRS THE AREA FROM THE NORTHWEST. EVEN WITH DELAYED CLEARING TRENDS IN MIND...ONGOING LOWS GENERALLY STILL LOOK ON TARGET EXCEPT MAYBE A MINOR ADJUSTMENT UPWARD ACRS THE FAR EASTERN CWA. WITH LIGHT WINDS AND POSSIBLE CLEARING HOLES UNDER RIDGE AXIS...WILL KEEP THE PATCHY FOG MENTION INTRODUCED BY PREVIOUS SHIFT ACRS GENERALLY THE EASTERN HALF OF THE DVN CWA. WITH LACK OF CLEARING THIS AFTERNOON ACRS THE WESTERN HALF OF THE CWA AND THUS LIMITED DRYING...PATCHY FOG WORDING MAYBE WARRANTED FURTHER TO THE WEST. THURSDAY...SOME OF THE RETURN FLOW GRADIENT AND SUNSHINE GOING ON NOW ACRS THE EAST-CENTRAL PLAINS WILL MAKE ITS WAY ACRS THE LOCAL AREA. INCREASING SOUTHERLY WINDS AND LLVL WARM AIR ADVECTION SHOULD TRANSLATE LOCALLY TO WHAT IS CURRENTLY GOING ON ACRS EASTERN NEB AND FAR WESTERN IA...WIDESPREAD MID TO UPPER 50S WITH A CHANCE AT A 60 DEGREE READING BY LATE THU AFTERNOON. ..12.. LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY... NEAR RECORD WARMTH FRIDAY AND SATURDAY...THEN SIGNIFICANT RAINS WITH A STRONG COLD FRONTAL PASSAGE SUNDAY THE MAIN FORECAST ISSUES. OVERVIEW...LIMITED UPSTREAM SENSIBLE WEATHER INITIALIZATION ISSUES WITH D_PROG_DT AND MOISTURE BIASES SUPPORTING WITH COLD FRONT USING GFS AS THE PRIMARY TOOL. THIS SUPPORTS WIDESPREAD SEASONABLE HEAVY RAINFALL TOTALS OF .5+ OF AN INCH...UP TO LOCALLY 2.0 INCHES. THURSDAY NIGHT THROUGH FRIDAY...FAIR SKIES WITH INCREASING SOUTH WINDS THAT WILL BECOME BREEZY BY FRIDAY PM. NEARLY STEADY TO POSSIBLY SLOWLY RISING MINS IN THE 30S THURSDAY AM. THEN HIGHS IN THE UPPER 50S NE TO LOWER 60S SW WITH POSSIBLY HIGHER VALUES IF ENOUGH SUNSHINE AND BL MIXING OCCURS. FRIDAY NIGHT...VERY MILD WITH MINS WITHIN 5 DEGREES OF RECORD WARM MINS RANGING FROM UPPER 40S NE TO THE LOWER TO MIDDLE 50S SW SECTIONS. LOTS OF HIGH CLOUDS SHOULD ARRIVE INTO THE AREA FRIDAY NIGHT. SATURDAY AND SATURDAY NIGHT...STRONG WAA TO KEEP REGION WELL ABOVE NORMAL WITH TEMPERATURES WITHIN 5 DEGREES OF RECORDS. KEPT VERY LOW POPS WITH LIGHT -SHRA POSSIBLE WITH HIGH PW/S AND WEAK UPPER LEVEL DISTURBANCES INTERACTING WITH LOW LEVEL JET. LOCAL TOOLS SUPPORT LOWER 70S POSSIBLE WITH ENOUGH SUNSHINE FOR HIGHS AND MINS ONCE AGAIN IN THE LOWER/MIDDLE 50S. SUNDAY AND SUNDAY NIGHT...STRONG COLD FRONT TO PASS WITH TEMPERATURES CRASHING 25-30+ PLUS DEGREES WITHIN 6 HOURS OF THE FRONT PASSING. SIGNIFICANT BANDS OF MODERATE TO LOCALLY HEAVY RAIN/RAINSHOWERS AND SOME EMBEDDED BRIEF THUNDER ALONG AND JUST BEHIND THE FRONT. EXPECT A LARGE GRADIENT FOR MAX TEMPERATURES. GONE WITH NEAR 50F FAR NW TO THE MIDDLE 60S FAR SW SECTIONS. LIKELY THIS GRADIENT WILL BE GREATER ONCE TIMING ISSUE BETTER RESOLVED IN THE NEXT COUPLE OF DAYS. PW VALUES NEAR 1.5 INCHES AHEAD OF FRONT PER LOCAL TECHNIQUES CONFIRM AT LEAST .5 INCHES OF RAINFALL WITH 1.5+ INCHES WITH TRAINING AND EVEN HIGHER POSSIBLE WITH ANY WAVE ON THE FRONT. MONDAY THROUGH WEDNESDAY...FAIR SKIES AND SEASONABLY COLD WITH BELOW NORMAL TEMPERATURES. HIGHS MOSTLY IN THE MID 30S TO LOWER 40S AND MINS IN THE 20S...POSSIBLY UPPER TEENS IN FAVORED LOW LYING LOCATIONS. NICHOLS && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1038 PM MST MON NOV 5 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 112 PM MST MON NOV 5 2012 LATEST WATER VAPOR AND RUC ANALYSIS DEPICT AN UPPER LEVEL RIDGE OVER THE WEST COAST...A SHORT WAVE TROUGH OVER SOUTHWEST CANADA WITH HIGH CLOUDS AHEAD OF IT OVER MONTANA SOUTH INTO COLORADO AND KANSAS. ANOTHER SHORT WAVE TROUGH WAS LOCATED OVER EASTERN OKLAHOMA AND CONTINUES TO DEEPEN. AT THE SURFACE A WARM FRONT WAS IN PLACE ALONG THE KS/CO BORDER NORTH INTO FAR SOUTHWEST SOUTH DAKOTA THANKS TO THE DOWNSLOPE WINDS COMING OFF THE ROCKIES. TONIGHT A SHORT WAVE RIDGE IN BETWEEN THE TROUGH OVER CANADA AND THE ONE TO OUR SOUTHEAST WILL MOVE OVER THE AREA. AT THE SURFACE A TROUGH WILL MOVE IN AHEAD OF THE UPPER LEVEL RIDGE. WINDS WILL SHIFT WEST WITH THE TROUGH PASSAGE THEN TURN BACK NORTH BEHIND IT. WITH A DRY ENVIRONMENT IN PLACE THE TROUGH PASSAGE WILL BE DRY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 256 PM MST MON NOV 5 2012 FORECAST CONCERNS WILL BE THE AMOUNT OF WARMUP/FIRE WEATHER CONCERNS WEDNESDAY THROUGH FRIDAY FOLLOWED BY COLDER TEMPERATURES/CHANCE OF PRECIPITATION NEXT WEEKEND. SATELLITE SHOWING AN AMPLIFIED/AMPLIFYING AND ACTIVE FLOW FROM THE PACIFIC INTO THE WESTERN ATLANTIC. SYSTEMS TO NOTE...DEEPENING SOON TO BE STRONG SYSTEM DIGGING INTO THE EASTERN PORTION OF THE COUNTRY WITH VERY STRONG SYSTEM MOVING/DEVELOPING IN SOUTHERN CANADA AT THIS TIME. DRY AIR MASS CURRENTLY RESIDES OVER THE AREA. AT JET LEVEL...THE NAM FOLLOWED BY THE GFS WAS DOING THE BEST ON THE VERY STRONG THAT RUNS FROM THE GULF OF ALASKA AND ON THE WEST SIDE OF DEVELOPING EASTERN CONUS SYSTEM. AT MID LEVELS...THE GFS WAS DOING A LITTLE BETTER THAN EVERYTHING ELSE. THE SREF AND NAM WERE DOING BEST ON THE SURFACE WIND AND PRESSURE FIELD. THE NAM...GFS AND CANADIAN WERE DOING BEST AT THIS TIME ON THE LOW LEVEL THERMAL FIELD. TUESDAY NIGHT...LITTLE CLOUD COVER AND LIGHT WINDS...ESPECIALLY IN THE EAST...WILL ALLOW TEMPERATURES TO FALL BELOW GUIDANCE. MINS RECENTLY HAVE FALLING WELL BELOW NWP. WENT IN THAT DIRECTION AND CLOSER TO THE GEM 2 METER TEMPERATURES. WEDNESDAY/WEDNESDAY NIGHT...DURING THE DAY THE SURFACE RIDGE PULLS AWAY WITH A CHILLY START...ESPECIALLY IN THE EAST. NEWER NAM IS LESS AGGRESSIVE WITH THE DOWNSLOPE COMPONENT. HOWEVER...WILL HAVE PLENTY OF SUN AND WESTERLY FLOW ALOFT. KEPT TEMPERATURES ABOUT THE SAME EXCEPT WARMING THEM UP A TOUCH. THE WIND FIELD LOOKS TO BE A LITTLE LIGHT...ESPECIALLY IN THE EAST. AS TROUGH LINE PASSES THROUGH THE TEMPERATURES WILL DROP WITH THEM WARMING UP AS DOWNSLOPE WINDS INCREASE BEHIND THE TROUGH. SO WILL BE A LITTLE TRICKY. THURSDAY...MODELS ALL OVER THE PLACE ON BOUNDARY PLACEMENT AND TIMING AND RESULTING LOW LEVEL TEMPERATURES. CONSIDERING THE EXPECTED FLOW ALOFT...THE MODELS MAY BE RUSHING THINGS A LITTLE BIT. AT THIS TIME...DID A COMPROMISE BETWEEN THE WARMEST AND COOLEST TEMPERATURES BUT DEFINITELY COULD SEE IT BEING WARMER. THURSDAY NIGHT THROUGH MONDAY...MAJOR FEATURE OF INTEREST IS HOW THE DEVELOPING WESTERN TROUGH WILL AFFECT THE WEATHER. THE MODELS AND ENSEMBLES HAVE THE SAME GENERAL IDEA OF AN ELONGATED TROUGH WITH THE STRONGEST/BEST DYNAMICS MUCH FURTHER NORTH AND SPLITTING OFF THE WEAKER SOUTHERN END FURTHER SOUTH LEAVING OUR AREA IN THE MIDDLE. MODELS DO DIFFER ON THE SPEED OF THE TROUGH WITH MORE SUPPORT FOR A SLOWER ARRIVAL. TEMPERATURES THURSDAY NIGHT WILL BE RATHER TRICKY. COLD FRONT THAT IS EXPECTED TO MOVE THROUGH SOMETIME ON THURSDAY IS EXPECTED TO RETURN NORTH AS A WARM FRONT THURSDAY NIGHT INTO FRIDAY. MODEL IN GENERAL AGREEMENT ON FRIDAY WITH THE FRONT NEAR OR NORTH OF THE FORECAST AREA BY LATE IN THE DAY. OVER THE SOUTHERN HALF TO TWO THIRDS...MODELS AGREE ON VERY WARM 850 MB TEMPERATURES. WILL HAVE DEEP SOUTHWEST FLOW ALOFT. AT THIS TIME DO NOT EXPECT THICK CLOUD COVER. AS A RESULT OF THAT AND COLLABORATION...WARMED UP MAXES. THIS WARM UP STILL MAY NOT BE ENOUGH. FRIDAY NIGHT INTO SATURDAY THE FRONT COMES BACK SOUTH AS A COLD FRONT. SOME DISCREPANCY ON TIMING BUT THERE LOOKS TO BE A THICKENING CLOUD DECK AND DEVELOPING PRECIPITATION THROUGH THE DAY. SO LEFT THE INHERITED INIT ALONE. VERY COLD TEMPERATURES FOLLOWING ESPECIALLY FOR SATURDAY NIGHT INTO SUNDAY NIGHT. INIT GRIDS LOOK FINE BUT DID MAKE A MINOR ADJUSTMENT DOWN. SATURDAY...ESPECIALLY FROM THE AFTERNOON...INTO SUNDAY LOOKS TO BE OUR CHANCE FOR PRECIPITATION. ONLY CONCERN NOW IS IF THE SLOWER SOLUTIONS PREVAIL...THE PRECIPITATION COULD START LATER IN THE DAY ON SATURDAY AND CONTINUE THROUGH MORE OF SUNDAY. DESPITE THE BRUNT OF THE LIFT BEING FURTHER NORTH...RIGHT REAR QUADRANT OF JET...VERY STRONG PV ANOMALY...AND STRONG CO-LOCATED MESOSCALE FORCING LOCATED WITH FAVORABLE THETA-E LAPSE RATES...DO SUPPORT LIGHT PRECIPITATION OCCURRING. THINK WE WILL GET SOMETHING JUST NOT SURE HOW MUCH. AM CONCERNED AND WILL HAVE TO BE WATCHED CAREFULLY IN UPCOMING FORECASTS OF BANDED PRECIPITATION DEVELOPING OVER THE AREA. KEPT THE PHASE RAIN SATURDAY AFTERNOON AND SWITCHED IT OVER TO ALL SNOW SATURDAY NIGHT. DEPENDING ON HOW LONG THE PRECIPITATION LINGERS INTO SUNDAY...COULD BE ALL SNOW OR A RAIN AND SNOW MIXTURE. FOR THE PRECIPITATION KEPT WHAT THE INIT GRID PRODUCED. REMAINDER OF THE FORECAST IS DRY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1034 PM MST MON NOV 5 2012 WINDS WILL SHIFT TO THE NORTHWEST OVERNIGHT AS A SURFACE TROUGH MOVES EAST. CONDITIONS WILL BE VFR AS A FEW MID LEVEL AND SCATTERED TO BROKEN MID LEVEL CLOUDS COTNINUE. WINDS WILL BECOME LIGHT AND VARIABLE AGAIN TUESDAY NIGHT AS HIGH PRESSURE SETTLES INTO THE AREA. && .FIRE WEATHER... ISSUED AT 256 PM MST MON NOV 5 2012 ON WEDNESDAY...RELATIVE HUMIDITIES WILL BECOME LOW. HOWEVER THE WIND FIELD LOOKS TO BE TOO LIGHT SO DO NOT EXPECT ANY FIRE WEATHER HIGHLIGHTS. ON FRIDAY...THIS DAY WILL HAVE TO BE WATCHED CAREFULLY. RELATIVE HUMIDITIES BE SOUTH OF THE WARM FRONT. WINDS WILL ALSO PICK UP IN THE SAME AREA. IF WARM FRONT IS FASTER MOVING NORTH AND THE WINDS END UP STRONGER...THERE MAY BE A NEED FOR A FIRE WEATHER HIGHLIGHT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JTL LONG TERM...BULLER AVIATION...FS FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1040 PM CST MON NOV 5 2012 .UPDATE... SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE OVER THE COASTAL WATERS...WITH ACTIVITY ENDED OVER LAND. HAVE GONE AHEAD AND CANCELLED WW 674...WITH WW 673 HAVING EXPIRED AT 9 PM. MADE SOME ADJUSTMENTS TO POPS/WX TO REFLECT CONVECTIVE TRENDS. DESPITE PASSAGE OF FRONTAL BOUNDARY THIS EVENING...WINDS REMAIN VERY LT ACRS THE AREA. BOTH 03Z RUC AND 00Z NAM SHOW THE POSSIBILITY OF FOG OVER ERN ZONES TONIGHT...AND GIVEN THE COMBINATION OF LT WINDS...CLEARING SKIES AND SFC MOISTURE...WENT AHEAD AND INCLUDED PATCHY FOG MAINLY FM POE TO LCH EASTWARD. FOR THE MARINE ZONES...ADDED EXERCISE CAUTION WITH NLY WINDS EXPECTED TO STRENGTHEN TO 15-20 KT TONIGHT. UPDATED PRODUCTS HAVE BEEN SENT. 24 && .PREV DISCUSSION... /ISSUED 717 PM CST MON NOV 5 2012/ UPDATE... REMOVED OUR INTERIOR SE TX COUNTIES FM WATCH 673...WITH CONVECTION CONTINUING TO SHIFT SOUTH AND EAST. UPDATED GRIDS AND PRODUCTS. 24 PREV DISCUSSION... /ISSUED 557 PM CST MON NOV 5 2012/ UPDATE... A QUICK UPDATE TO ADD SEVERE TSTM WATCH 674 IN EFFECT UNTIL 1 AM FOR SRN LA AND THE ADJACENT COASTAL WATERS. THIS IS IN ADDITION TO WATCH 673...RESULTING IN MOST OF THE AREA...EXCEPT FOR THE EXTREME NRN TIER OF LA PARISHES...UNDER A WATCH. SCT SEVERE TSTMS CONTINUE TO DEVELOP AND MOVE ACRS SRN LA...INCLUDING A RATHER POTENT STORM THAT JUST MOVED OVER THE OFFICE...DROPPING PEA TO QUARTER SIZE HAIL AND PRODUCING A WIND GUST TO 60 KT! 24 PREV DISCUSSION... /ISSUED 430 PM CST MON NOV 5 2012/ DISCUSSION... LATEST UPPER AIR ANALYSIS/WATER VAPOR IMAGERY SHOWED A VIGOROUS MID/UPPER LOW DIVING SOUTHEAST INTO THE LOWER MS RIVER VALLEY...WITH A SECONDARY SHORTWAVE JUST ENTERING THE NORTHERN PLAINS. LATEST SFC ANALYSIS INDICATED CDFNT WAS JUST NORTH/WEST OF A SHREVEPORT LOUISIANA TO COLLEGE STATION TEXAS LINE...EXTENDING SOUTHWEST OF A SFC LOW OVER SOUTHWEST ARKANSAS. ISOLATED TO SCATTERED CONVECTION HAS DEVELOPED LATE THIS AFTERNOON AS ROBUST SYNOPTIC LIFT ACTS UPON THE MOIST UNSTABLE WEDGE IN PLACE OVER TE AREA. THIS ACTIVITY IS EXPECTED TO CONTINUE INTO THE EVENING HOURS ALONG AND AHEAD OF THE SOUTHWARD MOVING FRONT. A SVR TSTM WATCH IS IN EFFECT FOR EAST TX AND SW LA UNTIL 9 PM...AND THIS LOOKS REASONABLE AS FCST SOUNDINGS ARE SUPPORTIVE OF A HAIL/WIND THREAT. THE CDFNT IS PROGGED TO REACH THE COAST BY EARLY/MID EVENING...AND CONTINUE SOUTHWARD THROUGH THE COASTAL WATERS AS THE UPPER LOW PIVOTS EAST THROUGH NORTHERN MS/AL. COOLER AND DRIER AIR IS EXPECTED IN THE WAKE OF THE FRONT...WITH LOW TEMPERATURES TUE MORNING A GOOD 10 DEGREES OR SO COOLER THAN THEY WERE TODAY. THE CAA IS FCST TO BECOME A BIT MORE NEUTRAL BY TOMORROW...AND WILL BE FURTHER OFFSET BY GOOD DIURNAL HEATING. A SECONDARY SURGE...OR REINFORCING FRONT...IS EXPECTED TO ACCOMPANY THE UPSTREAM SHORTWAVE TUESDAY NIGHT INTO WED...THOUGH IT WILL BE SOMETHING OF A GLANCING BLOW AS THE CORE OF COLDEST AIR WILL PASS TO OUR EAST. NO REAL CHANGES MADE TO THE EXTENDED FCST...AS GLOBAL MODELS CONCUR WITH THE NORTHWESTERLY FLOW ALOFT TRANSITIONING TO UPPER RIDGING THURSDAY...WHICH THEN GIVES WAY TO A DEEP AND STRENGTHENING LOW TO MID LEVEL SOUTHERLY FETCH INTO THE WEEKEND AS A LARGE UPPER TROF CARVES OUT OVER THE WESTERN CONUS. THEY CONTINUE TO DIFFER A BIT ON THE TIMING OF THE NEXT FRONT...WITH THE ECMWF A LITTLE SLOWER THAN THE GFS. HIGHEST RAIN CHANCES PEGGED FOR SUNDAY NIGHT INTO MONDAY TIME PERIOD STILL LOOK GOOD. MARINE... SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THE REST OF THIS AFTERNOON INTO THIS EVENING AS A VIGOROUS UPPER LEVEL SYSTEM DIVES SOUTHEAST THROUGH THE LOWER MISSISSIPPI RIVER VALLEY. THIS SYSTEM WILL DRIVE A COLD FRONT THROUGH THE COASTAL WATERS TONIGHT...WITH GUSTY NORTH WINDS AND BUILDING SEAS EXPECTED AFTER MIDNIGHT IN ITS WAKE. AT THIS TIME...WITH THE SEVERE THUNDERSTORM WATCH IN EFFECT...AND CONDITIONS LOOKING BORDERLINE BETWEEN SCEC AND SCA...I HAVE HELD OFF ON ANY MARINE HEADLINES OR ADVISORIES. WINDS AND SEAS WILL BEGIN SUBSIDE ON TUESDAY...BUT OFFSHORE FLOW WILL PREVAIL THROUGH WEDNESDAY NIGHT. SOUTHERLY WINDS ARE EXPECTED TO RETURN ON THURSDAY...AND GRADUALLY STRENGTHEN INTO THE WEEKEND. 13 && .PRELIMINARY POINT TEMPS/POPS... KLCH 52 69 47 73 / 30 10 0 0 KBPT 53 73 50 76 / 30 10 0 0 KAEX 48 67 44 70 / 20 10 0 0 KLFT 53 69 46 71 / 50 10 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT EXERCISE CAUTION UNTIL 10 AM CST TUESDAY FOR COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT 20 NM-COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM- COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM-WATERS FROM INTRACOASTAL CITY TO CAMERON LA FROM 20 TO 60 NM-WATERS FROM CAMERON LA TO HIGH ISLAND TX FROM 20 TO 60 NM-WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1242 PM EST TUE NOV 6 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 518 AM EST TUE NOV 6 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE EAST RESULTING IN NW FLOW FROM WRN CANADA THROUGH THE PLAINS. AN UPSTREAM SHORTWAVE TROUGH EXTENDING FROM NW MN INTO NW IA WAS DIVING TO THE SOUTHEAST. AT THE SFC...A TROUGH EXTENDED FROM LAKE WINNIPEG THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF 290K-295K ISENTROPIC LIFT AHEAD OF THE TROUGH AND WEAK TO MODERATE 700-500 MB QVECTOR CONV SUPPORTED AN AREA OF PCPN FROM NE MN INTO NRN IA. THE STRONGER FORCING ASSOCIATED WITH THE SHORTWAVE REMAINED TO THE SOUTH OVER SRN MN. MOST OF THE PCPN WAS FALLING AS RAIN WITH -SN ON THE BACK EDGE OF THE PCPN OVER NE MN. IR LOOP SHOWED THAT MID CLOUDS HAD SPREAD ACROSS THE WEST HALF OF UPPER MI WHILE ANOTHER BAND OF CLOUDS OFF OF LAKE MI HAD EXPANDED OVER THE ERN CWA. TODAY...WITH THE STRONGER DYNAMICS ASSOCIATED WITH THE SHRTWV PASSING TO THE SW OF UPPER MI...MODELS HAVE TRENDED TOWARD SMALLER QPF AMOUNTS THROUGH THE AREA...ESPECIALLY OVER THE EAST AND WHERE DOWNSLOPE FLOW PREVAILS N CNTRL NEAR LAKE SUPERIOR. FCST CONTINUED TO UTILIZE NAM WET-BULB ZERO HEIGHTS IN DEFINING WARM LAYER FOR PCPN TYPE WITH MAINLY SNOW OVER THE HIGHER TERRAIN WEST AND RAIN ELSEWHERE. WITH QPF LESS THAN A TENTH OF AN INCH...SNOW AMOUNTS SHOULD ALSO AMOUNT TO LESS THAN AN INCH. WITH 850 MB TEMPS TO AROUND -5C AND NRN LAKE MI WATER TEMP NEAR 10C...HIGHER RES MODELS SUGGEST THAT INSTABILITY WILL BE GREAT ENOUGH TO SUPPORT A BAND OF PCPN OFF OF LAKE MI. THE BAND WOULD BE EXPECTED TO DEVELOP ACROSS THE ERN LAKE TO THROUGH BEAVER ISLAND INTO MACKINAC AND FAR SE LUCE COUNTY. AS THE DEEPER MOISTURE MOVES IN DURING THE AFTERNOON AND WINDS VEER FROM SW TO S THE BAND MAY SHIFT TO NEAR MANISTIQUE/GRAND MARAIS AND THEN TOWARD THE GARDEN PENINSULA AND CNTRL ALGER COUNTY TONIGHT. CONFIDENCE IN THESE DETAILS IS STILL LIMITED AND ONLY LIGHT PCPN AMOUNTS ARE EXPECTED. LOW LEVEL TEMP PROFILES SUGGEST THAT THE PCPN WOULD BE MAINLY RAIN. MODELS HAVE TRENDED TOWARD A SLOWER PROGRESSION WITH THE SFC TROUGH SOT THAT A SWITCH TO ONSHORE FLOW OVER THE WEST WILL BE DELAYED. HOWEVER...SOME LINGERING SNOW/RAIN SHOWERS MAY BE POSSIBLE NEAR THE TROUGH AXIS...ESPECIALLY DURING THE EVENING. 850 MB TEMPS NEAR -4C AND ONLY WEAK ONSHORE NW FLOW LATE TONIGHT WILL ONLY PROVIDE MARGINAL SUPPORT FOR LAKE ENHANCED PCPN. SO...ANY PCPN AMOUNTS WILL BE VERY LIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 518 AM EST TUE NOV 6 2012 BY 12Z WEDNESDAY THE 500MB WAVES WILL BE JOINING FORCES ACROSS THE OHIO VALLEY TO MID ATLANTIC STATES...WITH THE RIDGE OVER MUCH OF THE W HALF OF THE NATION. EXPECT THE RIDGE TO BUILDING BACK ACROSS THE UPPER GREAT LAKES ON WEDNESDAY...THANKS TO OUR NEXT SIGNIFICANT SYSTEM DROPPING FROM THE GULF OF AK TO THE PACIFIC NW. MOISTURE WILL BE ON THE DECREASE...WITH INVERSION HEIGHTS STEADILY LOWERING AOB 4-5KFT. THE 500MB RIDGE OVERHEAD WILL BECOME SUPPRESSED THURSDAY AFTERNOON THROUGH FRIDAY...WITH ZONAL FLOW...THANKS TO A SYSTEM SWINGING ACROSS E CANADA. EXPECT A WEAK COLD FRONT TO NEAR FROM THE W/NW FRIDAY IN BETWEEN THE SYSTEM OVER CANADA AND THE NEXT SYSTEM OF CONCERN ORGANIZING ACROSS THE WY/CO ROCKIES. THIS WILL DO LITTLE FOR US...OTHER THAN BRING CLOUDS TO THE REGION AND A FEW SHOWERS. THE COLD FRONT SHOULD PUSH NORTH IN THE FORM OF A WARM FRONT ON SATURDAY IN ADVANCE OF THE LOW PRESSURE ACROSS THE CENTRAL PLAINS STATES. BY 00Z SUNDAY THE WX MAP SHOULD SHOW THE ELONGATED SFC LOW STRETCHED FROM W MN TO KS...AND THE 500MB TROUGH TAKING UP THE W HALF OF THE NATION. ALONG WITH A WARM UP INTO THE LOW 50S ON INCREASED SOUTHERLY WINDS FOR THE WEEKEND THIS SYSTEM WILL LIKELY ALSO BRING WET WEATHER AND THUNDERSTORMS AS THE SFC LOW LIFTS INTO ONTARIO ON SUNDAY. KEPT THE SLIGHT CHANCE TS POTENTIAL FOR SATURDAY AFTERNOON THROUGH SUNDAY MORNING...DIMINISHING W TO E DURING THE AFTERNOON. KEPT NON-DIURNAL TEMPS FOR SUNDAY...WITH LOWERING VALUES W TO E DURING THE DAY AS COLDER AIR RUSHES IN. IF TIMING OF THE COLD FRONT STAYS CONSISTENT...WILL LIKELY NEED TO INCREASE TEMPS A BIT OVER THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR E OF MQT /GIVEN STEADY 20KT S FLOW AT THE SFC AND 850MB WINDS OF 45-50KTS/. TEMPS SHOULD BE COLD ENOUGH FOR SNOW OVER FAR W UPPER MI BY 00Z MONDAY. HOWEVER...THE BULK OF THE MOISTURE WILL BE E BY THEN. THE 00Z GFS OFF OF BUFKIT WAS INDICATING THE POTENTIAL FOR 4-5IN AT IWD...AND AROUND 2.5IN AT CMX THROUGH 12Z TUESDAY. STILL...SOME OF THE COLDEST AIR OF THE YEAR SLIDING OVER LAKE SUPERIOR AND FAVORABLE WINDS SHOULD BE ENOUGH TO SUSTAIN LAKE EFFECT SNOW AS THE 500MB TROUGH SLOWLY MOVES ACROSS AND E OF THE AREA. THE 2-5IN MAY END UP BEING A LOW ESTIMATE IF THE 06/00Z GFS IS CORRECT...WITH A SECONDARY LOW DEVELOPING NEAR AK SUNDAY NIGHT AND PUSHING UP ALONG THE EXITING COLD FRONT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1241 PM EST TUE NOV 6 2012 LIGHT RAIN AND SNOW SHOWERS WILL CONTINUE TO MOVE INTO EACH OF THE TAF SITES THROUGH THE AFTERNOON AND EVENING HOURS. PRECIPITATION INTENSITY SHOULD REMAIN FAIRLY LIGHT AS THE BEST FORCING IS EXPECTED TO REMAIN SOUTH OF THE AREA...OVER CENTRAL WI. WINDS SHOULD NOT BE TOO STRONG AT ANY OF THE TAF SITES...HOWEVER THERE COULD BE GUSTS UP TO 20 KNOTS THROUGH THE AFTERNOON NEAR CMX AND SAW. CEILINGS WILL LIKELY COME DOWN AT EACH OF THE TAF SITES...WITH EACH SITE DROPPING TO IFR AND POSSIBLY LIFR AFTER MIDNIGHT TONIGHT. AS A TROUGH MOVES ACROSS THE REGION OVERNIGHT AND REMAINS IN PLACE THROUGH EARLY WEDNESDAY MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 518 AM EST TUE NOV 6 2012 SOUTH WINDS OF 15 TO 25 KNOTS AHEAD OF A TROUGH WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AND TONIGHT. WINDS WILL THEN BECOME LIGHT AS HIGH PRES BUILDS INTO THE AREA WEDNESDAY. SW WINDS WILL AGAIN INCREASE INTO THE 15 TO 25 KNOT RANGE THURSDAY AS ANOTHER TROUGH APPROACHES THE REGION. GALES MAY BE POSSIBLE BY LATE SATURDAY INTO SUNDAY NIGHT AS A LOW PRESSURE SYSTEM LIFTS NORTHEAST THROUGH MINNESOTA INTO NORTHWEST ONTARIO. HOWEVER...THERE IS STILL CONSIDERABLE UNCERTAINTY WITH THE TRACK AND STRENGTH OF THE THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...KEC MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
657 AM EST TUE NOV 6 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 518 AM EST TUE NOV 6 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE EAST RESULTING IN NW FLOW FROM WRN CANADA THROUGH THE PLAINS. AN UPSTREAM SHORTWAVE TROUGH EXTENDING FROM NW MN INTO NW IA WAS DIVING TO THE SOUTHEAST. AT THE SFC...A TROUGH EXTENDED FROM LAKE WINNIPEG THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF 290K-295K ISENTROPIC LIFT AHEAD OF THE TROUGH AND WEAK TO MODERATE 700-500 MB QVECTOR CONV SUPPORTED AN AREA OF PCPN FROM NE MN INTO NRN IA. THE STRONGER FORCING ASSOCIATED WITH THE SHORTWAVE REMAINED TO THE SOUTH OVER SRN MN. MOST OF THE PCPN WAS FALLING AS RAIN WITH -SN ON THE BACK EDGE OF THE PCPN OVER NE MN. IR LOOP SHOWED THAT MID CLOUDS HAD SPREAD ACROSS THE WEST HALF OF UPPER MI WHILE ANOTHER BAND OF CLOUDS OFF OF LAKE MI HAD EXPANDED OVER THE ERN CWA. TODAY...WITH THE STRONGER DYNAMICS ASSOCIATED WITH THE SHRTWV PASSING TO THE SW OF UPPER MI...MODELS HAVE TRENDED TOWARD SMALLER QPF AMOUNTS THROUGH THE AREA...ESPECIALLY OVER THE EAST AND WHERE DOWNSLOPE FLOW PREVAILS N CNTRL NEAR LAKE SUPERIOR. FCST CONTINUED TO UTILIZE NAM WET-BULB ZERO HEIGHTS IN DEFINING WARM LAYER FOR PCPN TYPE WITH MAINLY SNOW OVER THE HIGHER TERRAIN WEST AND RAIN ELSEWHERE. WITH QPF LESS THAN A TENTH OF AN INCH...SNOW AMOUNTS SHOULD ALSO AMOUNT TO LESS THAN AN INCH. WITH 850 MB TEMPS TO AROUND -5C AND NRN LAKE MI WATER TEMP NEAR 10C...HIGHER RES MODELS SUGGEST THAT INSTABILITY WILL BE GREAT ENOUGH TO SUPPORT A BAND OF PCPN OFF OF LAKE MI. THE BAND WOULD BE EXPECTED TO DEVELOP ACROSS THE ERN LAKE TO THROUGH BEAVER ISLAND INTO MACKINAC AND FAR SE LUCE COUNTY. AS THE DEEPER MOISTURE MOVES IN DURING THE AFTERNOON AND WINDS VEER FROM SW TO S THE BAND MAY SHIFT TO NEAR MANISTIQUE/GRAND MARAIS AND THEN TOWARD THE GARDEN PENINSULA AND CNTRL ALGER COUNTY TONIGHT. CONFIDENCE IN THESE DETAILS IS STILL LIMITED AND ONLY LIGHT PCPN AMOUNTS ARE EXPECTED. LOW LEVEL TEMP PROFILES SUGGEST THAT THE PCPN WOULD BE MAINLY RAIN. MODELS HAVE TRENDED TOWARD A SLOWER PROGRESSION WITH THE SFC TROUGH SOT THAT A SWITCH TO ONSHORE FLOW OVER THE WEST WILL BE DELAYED. HOWEVER...SOME LINGERING SNOW/RAIN SHOWERS MAY BE POSSIBLE NEAR THE TROUGH AXIS...ESPECIALLY DURING THE EVENING. 850 MB TEMPS NEAR -4C AND ONLY WEAK ONSHORE NW FLOW LATE TONIGHT WILL ONLY PROVIDE MARGINAL SUPPORT FOR LAKE ENHANCED PCPN. SO...ANY PCPN AMOUNTS WILL BE VERY LIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 518 AM EST TUE NOV 6 2012 BY 12Z WEDNESDAY THE 500MB WAVES WILL BE JOINING FORCES ACROSS THE OHIO VALLEY TO MID ATLANTIC STATES...WITH THE RIDGE OVER MUCH OF THE W HALF OF THE NATION. EXPECT THE RIDGE TO BUILDING BACK ACROSS THE UPPER GREAT LAKES ON WEDNESDAY...THANKS TO OUR NEXT SIGNIFICANT SYSTEM DROPPING FROM THE GULF OF AK TO THE PACIFIC NW. MOISTURE WILL BE ON THE DECREASE...WITH INVERSION HEIGHTS STEADILY LOWERING AOB 4-5KFT. THE 500MB RIDGE OVERHEAD WILL BECOME SUPPRESSED THURSDAY AFTERNOON THROUGH FRIDAY...WITH ZONAL FLOW...THANKS TO A SYSTEM SWINGING ACROSS E CANADA. EXPECT A WEAK COLD FRONT TO NEAR FROM THE W/NW FRIDAY IN BETWEEN THE SYSTEM OVER CANADA AND THE NEXT SYSTEM OF CONCERN ORGANIZING ACROSS THE WY/CO ROCKIES. THIS WILL DO LITTLE FOR US...OTHER THAN BRING CLOUDS TO THE REGION AND A FEW SHOWERS. THE COLD FRONT SHOULD PUSH NORTH IN THE FORM OF A WARM FRONT ON SATURDAY IN ADVANCE OF THE LOW PRESSURE ACROSS THE CENTRAL PLAINS STATES. BY 00Z SUNDAY THE WX MAP SHOULD SHOW THE ELONGATED SFC LOW STRETCHED FROM W MN TO KS...AND THE 500MB TROUGH TAKING UP THE W HALF OF THE NATION. ALONG WITH A WARM UP INTO THE LOW 50S ON INCREASED SOUTHERLY WINDS FOR THE WEEKEND THIS SYSTEM WILL LIKELY ALSO BRING WET WEATHER AND THUNDERSTORMS AS THE SFC LOW LIFTS INTO ONTARIO ON SUNDAY. KEPT THE SLIGHT CHANCE TS POTENTIAL FOR SATURDAY AFTERNOON THROUGH SUNDAY MORNING...DIMINISHING W TO E DURING THE AFTERNOON. KEPT NON-DIURNAL TEMPS FOR SUNDAY...WITH LOWERING VALUES W TO E DURING THE DAY AS COLDER AIR RUSHES IN. IF TIMING OF THE COLD FRONT STAYS CONSISTENT...WILL LIKELY NEED TO INCREASE TEMPS A BIT OVER THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR E OF MQT /GIVEN STEADY 20KT S FLOW AT THE SFC AND 850MB WINDS OF 45-50KTS/. TEMPS SHOULD BE COLD ENOUGH FOR SNOW OVER FAR W UPPER MI BY 00Z MONDAY. HOWEVER...THE BULK OF THE MOISTURE WILL BE E BY THEN. THE 00Z GFS OFF OF BUFKIT WAS INDICATING THE POTENTIAL FOR 4-5IN AT IWD...AND AROUND 2.5IN AT CMX THROUGH 12Z TUESDAY. STILL...SOME OF THE COLDEST AIR OF THE YEAR SLIDING OVER LAKE SUPERIOR AND FAVORABLE WINDS SHOULD BE ENOUGH TO SUSTAIN LAKE EFFECT SNOW AS THE 500MB TROUGH SLOWLY MOVES ACROSS AND E OF THE AREA. THE 2-5IN MAY END UP BEING A LOW ESTIMATE IF THE 06/00Z GFS IS CORRECT...WITH A SECONDARY LOW DEVELOPING NEAR AK SUNDAY NIGHT AND PUSHING UP ALONG THE EXITING COLD FRONT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 656 AM EST TUE NOV 6 2012 EXPECTED VFR CONDITIONS ASSOCIATED WITH WEDGE OF DRY AIR OVER CENTRAL UPR MI/WI TO GIVE WAY TO MVFR CIGS W-E THIS MORNING AS STRENGTHENING SRLY FLOW BTWN DEPARTING HIGH PRES IN SE ONTARIO AND A LOW PRES TROUGH MOVING INTO MN DRAWS MOISTER AIR TO THE N. THERE MAY BE SOME LIGHT -RASN AS WELL...BUT PASSAGE OF MORE INTENSE DYNAMIC FORCING TO THE SOUTH WILL LIMIT INTENSITY AND ANY VSBY RESTRICTION. AS MOISTER AIR CONTINUES TO MOVE TO THE N...EXPECT IFR CONDITIONS TO DEVELOP AT SAW WITH FAVORABLE UPSLOPE SSE WIND. THIS DOWNSLOPE WIND WILL REDUCE THE THREAT OF IFR CONDITIONS AT CMX/IWD...BUT ARRIVAL OF LO PRES TROF/ WEAKER PRES GRADIENT AT IWD LATE IN THE TAF PERIOD SHOULD ALLOW FOR CONDITIONS TO DETERIORATE TO IFR THERE AS WELL. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 518 AM EST TUE NOV 6 2012 SOUTH WINDS OF 15 TO 25 KNOTS AHEAD OF A TROUGH WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AND TONIGHT. WINDS WILL THEN BECOME LIGHT AS HIGH PRES BUILDS INTO THE AREA WEDNESDAY. SW WINDS WILL AGAIN INCREASE INTO THE 15 TO 25 KNOT RANGE THURSDAY AS ANOTHER TROUGH APPROACHES THE REGION. GALES MAY BE POSSIBLE BY LATE SATURDAY INTO SUNDAY NIGHT AS A LOW PRESSURE SYSTEM LIFTS NORTHEAST THROUGH MINNESOTA INTO NORTHWEST ONTARIO. HOWEVER...THERE IS STILL CONSIDERABLE UNCERTAINTY WITH THE TRACK AND STRENGTH OF THE THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
523 AM EST TUE NOV 6 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 518 AM EST TUE NOV 6 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE EAST RESULTING IN NW FLOW FROM WRN CANADA THROUGH THE PLAINS. AN UPSTREAM SHORTWAVE TROUGH EXTENDING FROM NW MN INTO NW IA WAS DIVING TO THE SOUTHEAST. AT THE SFC...A TROUGH EXTENDED FROM LAKE WINNIPEG THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF 290K-295K ISENTROPIC LIFT AHEAD OF THE TROUGH AND WEAK TO MODERATE 700-500 MB QVECTOR CONV SUPPORTED AN AREA OF PCPN FROM NE MN INTO NRN IA. THE STRONGER FORCING ASSOCIATED WITH THE SHORTWAVE REMAINED TO THE SOUTH OVER SRN MN. MOST OF THE PCPN WAS FALLING AS RAIN WITH -SN ON THE BACK EDGE OF THE PCPN OVER NE MN. IR LOOP SHOWED THAT MID CLOUDS HAD SPREAD ACROSS THE WEST HALF OF UPPER MI WHILE ANOTHER BAND OF CLOUDS OFF OF LAKE MI HAD EXPANDED OVER THE ERN CWA. TODAY...WITH THE STRONGER DYNAMICS ASSOCIATED WITH THE SHRTWV PASSING TO THE SW OF UPPER MI...MODELS HAVE TRENDED TOWARD SMALLER QPF AMOUNTS THROUGH THE AREA...ESPECIALLY OVER THE EAST AND WHERE DOWNSLOPE FLOW PREVAILS N CNTRL NEAR LAKE SUPERIOR. FCST CONTINUED TO UTILIZE NAM WET-BULB ZERO HEIGHTS IN DEFINING WARM LAYER FOR PCPN TYPE WITH MAINLY SNOW OVER THE HIGHER TERRAIN WEST AND RAIN ELSEWHERE. WITH QPF LESS THAN A TENTH OF AN INCH...SNOW AMOUNTS SHOULD ALSO AMOUNT TO LESS THAN AN INCH. WITH 850 MB TEMPS TO AROUND -5C AND NRN LAKE MI WATER TEMP NEAR 10C...HIGHER RES MODELS SUGGEST THAT INSTABILITY WILL BE GREAT ENOUGH TO SUPPORT A BAND OF PCPN OFF OF LAKE MI. THE BAND WOULD BE EXPECTED TO DEVELOP ACROSS THE ERN LAKE TO THROUGH BEAVER ISLAND INTO MACKINAC AND FAR SE LUCE COUNTY. AS THE DEEPER MOISTURE MOVES IN DURING THE AFTERNOON AND WINDS VEER FROM SW TO S THE BAND MAY SHIFT TO NEAR MANISTIQUE/GRAND MARAIS AND THEN TOWARD THE GARDEN PENINSULA AND CNTRL ALGER COUNTY TONIGHT. CONFIDENCE IN THESE DETAILS IS STILL LIMITED AND ONLY LIGHT PCPN AMOUNTS ARE EXPECTED. LOW LEVEL TEMP PROFILES SUGGEST THAT THE PCPN WOULD BE MAINLY RAIN. MODELS HAVE TRENDED TOWARD A SLOWER PROGRESSION WITH THE SFC TROUGH SOT THAT A SWITCH TO ONSHORE FLOW OVER THE WEST WILL BE DELAYED. HOWEVER...SOME LINGERING SNOW/RAIN SHOWERS MAY BE POSSIBLE NEAR THE TROUGH AXIS...ESPECIALLY DURING THE EVENING. 850 MB TEMPS NEAR -4C AND ONLY WEAK ONSHORE NW FLOW LATE TONIGHT WILL ONLY PROVIDE MARGINAL SUPPORT FOR LAKE ENHANCED PCPN. SO...ANY PCPN AMOUNTS WILL BE VERY LIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 518 AM EST TUE NOV 6 2012 BY 12Z WEDNESDAY THE 500MB WAVES WILL BE JOINING FORCES ACROSS THE OHIO VALLEY TO MID ATLANTIC STATES...WITH THE RIDGE OVER MUCH OF THE W HALF OF THE NATION. EXPECT THE RIDGE TO BUILDING BACK ACROSS THE UPPER GREAT LAKES ON WEDNESDAY...THANKS TO OUR NEXT SIGNIFICANT SYSTEM DROPPING FROM THE GULF OF AK TO THE PACIFIC NW. MOISTURE WILL BE ON THE DECREASE...WITH INVERSION HEIGHTS STEADILY LOWERING AOB 4-5KFT. THE 500MB RIDGE OVERHEAD WILL BECOME SUPPRESSED THURSDAY AFTERNOON THROUGH FRIDAY...WITH ZONAL FLOW...THANKS TO A SYSTEM SWINGING ACROSS E CANADA. EXPECT A WEAK COLD FRONT TO NEAR FROM THE W/NW FRIDAY IN BETWEEN THE SYSTEM OVER CANADA AND THE NEXT SYSTEM OF CONCERN ORGANIZING ACROSS THE WY/CO ROCKIES. THIS WILL DO LITTLE FOR US...OTHER THAN BRING CLOUDS TO THE REGION AND A FEW SHOWERS. THE COLD FRONT SHOULD PUSH NORTH IN THE FORM OF A WARM FRONT ON SATURDAY IN ADVANCE OF THE LOW PRESSURE ACROSS THE CENTRAL PLAINS STATES. BY 00Z SUNDAY THE WX MAP SHOULD SHOW THE ELONGATED SFC LOW STRETCHED FROM W MN TO KS...AND THE 500MB TROUGH TAKING UP THE W HALF OF THE NATION. ALONG WITH A WARM UP INTO THE LOW 50S ON INCREASED SOUTHERLY WINDS FOR THE WEEKEND THIS SYSTEM WILL LIKELY ALSO BRING WET WEATHER AND THUNDERSTORMS AS THE SFC LOW LIFTS INTO ONTARIO ON SUNDAY. KEPT THE SLIGHT CHANCE TS POTENTIAL FOR SATURDAY AFTERNOON THROUGH SUNDAY MORNING...DIMINISHING W TO E DURING THE AFTERNOON. KEPT NON-DIURNAL TEMPS FOR SUNDAY...WITH LOWERING VALUES W TO E DURING THE DAY AS COLDER AIR RUSHES IN. IF TIMING OF THE COLD FRONT STAYS CONSISTENT...WILL LIKELY NEED TO INCREASE TEMPS A BIT OVER THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR E OF MQT /GIVEN STEADY 20KT S FLOW AT THE SFC AND 850MB WINDS OF 45-50KTS/. TEMPS SHOULD BE COLD ENOUGH FOR SNOW OVER FAR W UPPER MI BY 00Z MONDAY. HOWEVER...THE BULK OF THE MOISTURE WILL BE E BY THEN. THE 00Z GFS OFF OF BUFKIT WAS INDICATING THE POTENTIAL FOR 4-5IN AT IWD...AND AROUND 2.5IN AT CMX THROUGH 12Z TUESDAY. STILL...SOME OF THE COLDEST AIR OF THE YEAR SLIDING OVER LAKE SUPERIOR AND FAVORABLE WINDS SHOULD BE ENOUGH TO SUSTAIN LAKE EFFECT SNOW AS THE 500MB TROUGH SLOWLY MOVES ACROSS AND E OF THE AREA. THE 2-5IN MAY END UP BEING A LOW ESTIMATE IF THE 06/00Z GFS IS CORRECT...WITH A SECONDARY LOW DEVELOPING NEAR AK SUNDAY NIGHT AND PUSHING UP ALONG THE EXITING COLD FRONT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 617 PM EST MON NOV 5 2012 WITH EXPECTED WSHFT TO THE SSW THIS EVNG BTWN DEPARTING HI PRES IN SE ONTARIO AND APRCHG LO PRES TROF FM THE PLAINS...EXPECT AREA OF DRY AIR/MOCLR SKIES OVER MUCH OF WI TO MOVE IN AND RESULT IN PREDOMINANT VFR CONDITIONS MUCH OF TNGT. THE BEST CHC FOR THE MVFR CIGS TO LINGER WL BE AT SAW...WHERE AREA OF SC NEAR THE LK MI SHORE IN WI TO IMT MIGHT HOLD IN THRU THE NGT. MORE LO CLDS WL THEN ARRIVE W-E LATER TNGT IN ADVANCE OF LO PRES TROF. ALTHOUGH THE CIGS WL BE INITIALLY VFR PER UPSTREAM OBS...LOOK FOR MVFR CONDITIONS TO PREDOMINATE LATE TNGT THRU TUE AS STRENGTHENING SLY FLOW ADVECTS MORE LLVL MSTR INTO THE AREA. THIS STRENGTHENING FLOW MIGHT CAUSE MARGINAL LLWS AT IWD LATE TNGT/EARLY TUE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 518 AM EST TUE NOV 6 2012 SOUTH WINDS OF 15 TO 25 KNOTS AHEAD OF A TROUGH WILL DIMINISH FROM WEST TO EAST THIS AFTERNOON AND TONIGHT. WINDS WILL THEN BECOME LIGHT AS HIGH PRES BUILDS INTO THE AREA WEDNESDAY. SW WINDS WILL AGAIN INCREASE INTO THE 15 TO 25 KNOT RANGE THURSDAY AS ANOTHER TROUGH APPROACHES THE REGION. GALES MAY BE POSSIBLE BY LATE SATURDAY INTO SUNDAY NIGHT AS A LOW PRESSURE SYSTEM LIFTS NORTHEAST THROUGH MINNESOTA INTO NORTHWEST ONTARIO. HOWEVER...THERE IS STILL CONSIDERABLE UNCERTAINTY WITH THE TRACK AND STRENGTH OF THE THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1135 PM CST MON NOV 5 2012 .DISCUSSION... STILL A SMALL CHANCE OF SPRINKLES MOVING THROUGH THE REGION... GENERALLY ALONG AND NORTH OF I80 TONIGHT. AMOUNTS STILL APPEAR TO BE VERY LIGHT WITH MOSTLY TRACE AMOUNTS. ALSO STILL LOOKS INCREASINGLY WINDY THROUGH THE DAY TUESDAY...WITH WIND SPEEDS NEAR ADVISORY CRITERIA IN NORTHEAST NEBRASKA. DEWALD && .AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. MVFR CONDITIONS PERSIST AT KOMA...AND LIKELY WILL UNTIL 10-12Z BEFORE LOW CLOUDS SCATTER OUT. OTHERWISE...VFR CONDITIONS PREVAIL AT BOTH KLNK/KOFK. SOUTH SOUTHWEST WINDS AHEAD OF THE APPROACHING FRONT...SWITCHING TO NORTHWEST ONCE THE FRONT ARRIVES...ARRIVING AT KOFK BY 11Z...AND KOMA/KLNK BY 13-14Z. SUSTAINED WIND SPEEDS INCREASE TO 20 TO 25 KNOTS SUSTAINED...WITH GUSTS UP TO 30 TO 35 KNOTS...BUT SHOULD DIMINISH ONCE THE SUN GOES DOWN BY 07/00Z. DEWALD && .PREV DISCUSSION... /ISSUED 633 PM CST MON NOV 5 2012/ DISCUSSION... TWEAKED THE FORECAST JUST SLIGHTLY TO BRING PRECIP CHANCES INTO NORTHEAST NEBRASKA A FEW HOURS EARLIER...BASED ON RADAR ECHOS MOVING OUT OF SOUTH DAKOTA AND NORTH CENTRAL NEBRASKA. ALSO TRIMMED THE BACK EDGE OF THE PRECIP JUST A BIT...AND BROUGHT IT JUST A LITTLE BIT FURTHER SOUTH. EITHER WAY...IT WILL LIKELY BE VERY VERY LIGHT...PERHAPS ONLY JUST TRACE AMOUNTS. ALSO TWEAKED THE WINDS UP A COUPLE OF KNOTS ON TUESDAY IN NORTHEAST NEBRASKA. WINDS MAY BE JUST SHY OF WIND ADVISORY CRITERIA IN NORTHEAST NEBRASKA AROUND 30 MPH SUSTAINED. DEWALD PREV DISCUSSION... /ISSUED 318 PM CST MON NOV 5 2012/ SHORT TERM...TONIGHT THROUGH THURSDAY. MAIN FORECAST CONCERN IS SMALL CHANCE FOR SHOWERS IN OUR NORTHEAST OVERNIGHT. LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW THE REGION IN NORTHWESTERLY FLOW ALOFT WITH SHORTWAVE ENERGY QUICKLY DROPPING THROUGH THE SOUTHERN CANADIAN PRAIRIE PROVINCES. ASSOCIATED SFC LOW PRESSURE AREA CONTINUES TO QUICKLY MOVE SOUTHEAST AHEAD OF THIS UPPER FEATURE WITH WIDESPREAD SHOWERS ACROSS NORTH DAKOTA. THESE FEATURES WILL CONTINUE THEIR SOUTHWARD PROGRESSION AND SHOULD BRUSH THE NORTHEASTERN COUNTIES OVERNIGHT...MAINLY AFTER 06Z. HAVE ADDED A SMALL CHANCE FOR SHOWERS AS MOISTURE PROFILES ARE SLOW TO SATURATE LOWER LEVELS. IN ADDITION...ASSOCIATED SFC COLD FRONT WILL PUSH THROUGH THE FORECAST AREA TUESDAY MORNING. GOOD MOMENTUM TRANSFER SHOULD ALLOW GUSTY CONDITIONS INTO TUESDAY AFTERNOON BEHIND THE FRONT. HIGH TEMPERATURES SHOULD ONLY TOP OUT IN THE LOWER 50S ACROSS THE NORTHEASTERN CWA WITH UPPER 50S IN THE SOUTHWEST. SFC HIGH PRESSURE QUICKLY BUILDS IN WEDNESDAY MORNING BRINGING CLEAR AND CALM CONDITIONS. A GRADUAL WARMING TREND WEDNESDAY INTO THURSDAY IS EXPECTED AS A WESTERN RIDGE BUILDS EAST OVER THE AREA AND RETURN FLOW DEVELOPS AROUND SFC HIGH PRESSURE. KERN LONG TERM...THURSDAY NIGHT THROUGH MONDAY. LOOKS LIKE SOME ACTIVE WEATHER FOR THE WEEKEND WITH BIG SWINGS IN TEMPERATURES. THE EC/GFS/GEFS/CANADIAN ARE ALL IN FAIRLY GOOD AGREEMENT...WITH SOME TYPICALLY TIMING AND STRENGTH DIFFERENCES. THE FORECAST AREA WILL BE IN THE WARM SECTOR THURSDAY NIGHT WITH AN INVERTED TROF SETTLING INTO NORTHEAST NEBRASKA. THE GULF IS OPEN WITH H85 FLOW FROM TEXAS THROUGH THE PLAINS WITH THE DRY SLOT HEADING ACROSS NORTH CENTRAL KANSAS BY 12Z FRIDAY. THE SURFACE LOW INITIALLY OVER THE CENTRAL ROCKIES TRACKS NORTHEAST ALONG THE FRONT AND BY 18Z SATURDAY IS CENTERED SOMEWHERE BETWEEN EASTERN SOUTH DAKOTA/EASTERN NEBRASKA (GFS/EC/GEFS) OR MINNESOTA (CANADIAN). THE BULK OF THE PRECIPITATION WILL INITIALLY BE AHEAD OF...NORTH...AND TO THE WEST OF THE FORECAST AREA. SATURDAY NIGHT LOOKS TO BE THE BEST CHANCE FOR PRECIPITATION...ALTHOUGH THERE WILL BE LIFT/WAA DURING THE DAY SATURDAY. THE GFS HAS A SURGE OF HIGHER DEWPOINTS NEAR THE MISSOURI RIVER AND THEN LIFTING NORTH AND SHIFTING QUICKLY EAST. THE EC IS SLOWER WITH THE DEEP MOISTURE AND HOLDS ON TO THE HIGH 10 TO 12DEG C H85 DEWPOINTS. COMBINED WITH THE LIFT WITH THIS DYNAMIC SYSTEM THESE DIFFERENCES ACCOUNT FOR THE DIFFERENCES IN RESULTANT QPF WITH HIGHER PRECIPITATION AMOUNTS WITH THE EC. TEMPERATURES FRIDAY AND SATURDAY WILL BE IN THE 60S AND 70S AND MUCH COLDER FOR SUNDAY AND MONDAY WITH HIGHS IN THE 30S AND 40S. FOR NOW HAVE SOME CHANCE POPS SATURDAY AFTERNOON AND LIKELY POPS SATURDAY NIGHT AND DEPENDING ON IF THE SYSTEM SLOWS DOWN...SOME POPS INTO SUNDAY. WITH INSTABILITY AHEAD OF THE FRONT WILL INCLUDE THUNDER. THERE COULD BE A MIX IN THE NORTHEAST AS COLDER AIR WORKS INTO THE SYSTEM IN NORTHEAST NEBRASKA. SHOULD THERE BE LINGERING PRECIPITATION SUNDAY...THERE COULD BE A MIX OR MINOR ACCUMULATIONS SUNDAY. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1124 PM CST MON NOV 5 2012 .UPDATE... .AVIATION... VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH TUESDAY EVENING. A COLD FRONT WILL MOVE THROUGH OVERNIGHT. WINDS ACROSS NCNTL NEB EAST OF HIGHWAY 83 INCREASE TO 32025G35KT TUESDAY MORNING. LIGHT RAIN SHOWERS HAVE DEVELOPED ALONG AND BEHIND THE FRONT THIS EVENING. VFR IS EXPECTED BENEATH THOSE RADAR RETURNS. && .PREV DISCUSSION... /ISSUED 833 PM CST MON NOV 5 2012/ UPDATE... ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS WRN AND CNTL SD. IT LOOKS LIKE THERE IS ENOUGH MOISTURE ALOFT FOR SOME RAIN AT THE SFC BASED ON 00Z SOUNDINGS. OBSERVED STORM MOTION SHOULD CARRY THE LIGHT RAIN THRU NCNTL NEB OVERNIGHT. ALSO RAISED TEMPS A CATEGORY AS FAIRLY DENSE MID AND UPPER LEVEL CLOUDS SHOULD CONTINUE OVERNIGHT. PREV DISCUSSION... /ISSUED 547 PM CST MON NOV 5 2012/ UPDATE... AVIATION... VFR IS EXPECTED MOST AREAS TONIGHT AND TUESDAY. A COLD FRONT WILL MOVE THROUGH TONIGHT WITH WINDS INCREASING AFTER 15Z TO 32025G35KT ACROSS NCNTL NEB EAST OF HIGHWAY 83. SPRINKLES HAVE DEVELOPED AHEAD OF THE FRONT THIS EVENING. VFR IS EXPECTED BENEATH THOSE RADAR RETURNS. ALSO...THE BANK OF MVFR CIGS ACROSS NCNTL NEB GETS SHOVED EAST AS THE COLD FRONT APPROACHES LATE TONIGHT...09Z- 12Z. NOTE THE RUC SUGGESTS SOME POTENTIAL FOR MVFR CIGS LATE TONIGHT WITH THE COLD FRONT. FOR NOW PLAN ON VFR. BEST GUESS ON MVFR CAN BE MADE AS THE FRONT GETS CLOSER THIS EVENING. PREV DISCUSSION... /ISSUED 317 PM CST MON NOV 5 2012/ SYNOPSIS...ANALYSIS OF THE 19Z MSL DATA SHOWED A FRONTAL WAVE IN SOUTHERN SASKATCHEWAN. ASSOCIATED WITH THE SURFACE LOW...WATER VAPOR IMAGERY WAS SHOWING A POTENTIAL VORTICITY ANOMALY NEAR THE BOUNDARY BETWEEN EAST CENTRAL ALBERTA AND WEST CENTRAL SASKATCHEWAN. A SURFACE FRONT HAD MOVED OUT OF SOUTHERN ALBERTA AND SASKATCHEWAN INTO NORTHERN MONTANA. THERE WAS ALSO AN ABUNDANCE OF JETSTREAM-RELATED CIRRUS/CIRROSTRATUS STREAMING OVER THE MONTANA-WYOMING ROCKIES ON THE NORTHWEST FLOW. VISIBLE IMAGERY INDICATED SOME CUMULIFORM CLOUDINESS FROM CENTRAL TO SOUTHWEST NEBRASKA. SHORT TERM...A FRONT COMING OUT OF NORTHERN MONTANA WILL COME THROUGH NEBRASKA LATE TONIGHT TO EARLY TUESDAY AND BRING SOME PATCHY CLOUDINESS. THEN...RETURN FLOW WILL BRING THE FRONT BACK TOWARD THE EAST AGAIN TUESDAY NIGHT AND...WITH IT...SOME CLOUDINESS. TEMPERATURES TONIGHT WILL BE HELD TO THE MID TO UPPER 30S TONIGHT BY THE AREAS OF CLOUDINESS. WITH MORE SUNSHINE THAN TODAY AND BREEZIER CONDITIONS...TEMPERATURES TUESDAY WILL BE SOMEWHAT WARMER THAN TODAY. CLEARING SKY AND LIGHT WIND WILL LET TEMPERATURES FALL INTO THE 20S OVER THE AREA TUESDAY NIGHT. LONG TERM...A SIGNIFICANT LONG WAVE TROUGH IS STILL PROGGED TO PROGRESS EAST ACROSS THE THE PLAINS SATURDAY INTO SUNDAY. AHEAD OF THIS FEATURE...MILD WEATHER WILL CONTINUE...WITH HIGHS ABOVE NORMAL WEDNESDAY THROUGH FRIDAY. A DRASTIC CHANGE IN THE WEATHER WILL OCCUR SATURDAY...AS A STRONG COLD FRONT PLOWS SOUTHEAST ACROSS NEBRASKA. GUSTY NORTHWEST WINDS AND FALLING TEMPERATURES CAN BE EXPECTED BEHIND THE FRONT SATURDAY AFTERNOON...WITH LIGHT RAIN OR LIGHT SNOW DEVELOPING WITHIN AREA OF STRONG FRONTOGENESIS BEHIND THE FRONT. LIGHT SNOW WILL LINGER INTO SATURDAY NIGHT...AND SHOULD END BY SUNDAY MORNING AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA. IT IS STILL TOO EARLY TO KNOW EXACTLY HOW MUCH SNOW WILL ACCUMULATE...BUT ALL INDICATIONS ARE THAT AMOUNTS SHOULD BE LIGHT...WITH PERHAPS AN INCH OR TWO FALLING ACROSS NORTHWEST NEBRASKA. WILL CONTINUE TO MONITOR...AND UPDATE FORECASTS AS THE STORM SYSTEM GETS CLOSER. VERY CHILLY CONDITIONS ARE EXPECTED SUNDAY...WITH MANY AREAS STRUGGLING TO REACH THE FREEZING MARK. SOME TEMPERATURE RECOVERY IS EXPECTED MONDAY AS THE COLDEST AIR MOVES EAST OF THE AREA. AVIATION... NO SIGNIFICANT RESTRICTIVE WEATHER IS EXPECTED TONIGHT THROUGH TUESDAY. CEILINGS...IF ANY...WILL BE AT OR ABOVE 5000 FEET AGL. WIND IS EXPECTED TO INCREASE TUESDAY. IN NORTH CENTRAL NEBRASKA...NEAR ONL...BUB...BBW AND ANW...THE WIND IS EXPECTED TO BE 310-330 INCREASING TO 20-23G26-30 BY 18Z. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
944 AM EST TUE NOV 6 2012 .SYNOPSIS... HIGH PRESSURE WILL EXTEND OVER THE AREA FROM THE NORTH TODAY. STRONG LOW PRESSURE IS FORECAST TO DEVELOP OFF THE SOUTHEAST COAST THIS AFTERNOON AND MOVE OFF OF THE NORTH CAROLINA COAST TONIGHT. THE LOW WILL RAPIDLY INTENSIFY AS IT MOVES NORTHEAST OF THE AREA WEDNESDAY INTO THURSDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY AND SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 935 AM TUESDAY...SURFACE LOW PRESSURE CONSOLIDATING WELL EAST OF THE SOUTH CAROLINA COAST...AS CLOSED LOW DROPS WELL INTO THE DEEP SOUTH HELPING TO STRENGTHEN TO LOW OFFSHORE. PRECIPITATION SHIELD CONTINUES TO MOVE UP THE COAST WITH LIGHT RAIN ARRIVING DURING THE AFTERNOON HOURS. THE NAM12 AND GFS SEEMS TO HAVE A MUCH BETTER FEEL TO THE PRECIPITATION FIELD AS THE LATEST RAP SHOWS NO PRECIPITATION ON LAND THROUGH THE NEXT 18 HOURS. HAVE MADE ONLY MINOR TWEAKS TO THE FORECAST AT THIS TIME. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... AS OF 330 AM TUESDAY...LOW PRES WILL INTENSIFY AS IT MOVES OFFSHORE OF OUTER BANKS OVERNIGHT WITH PCPN SHIELD AFFECTING MOST OF AREA...BUT MAINLY ALONG AND E OF HWY 17. ADJUSTED QPF TO REFLECT AMOUNTS OF 0.50 TO 1 INCH NEAR COAST. WITH MODELS TRENDING TO SLIGHTLY FASTER AND WEAKER SYSTEM...EXPECT WINDS TO REMAIN BELOW ADVISORY CRITERIA AT THIS TIME. MOS GDNC BLEND IN DECENT AGREEMENT WITH PREVIOUS FCST MIN TEMPS...UPR 30S INLAND TO UPR 40S OBX. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 330 AM TUE...HAVE USED THE ECMWF FOR THE EXTENDED FORECAST AS IT MATCHES UP WELL WITH HPC`S SURFACE DEPICTION OVER THE NEXT SEVERAL DAYS. STRONG COASTAL LOW WILL BE MOVING NORTHWARD DURING THE DAY AWAY FROM THE NORTH COAST. HIGHS WON`T MAKE IT OUT OF THE MID TO UPPER 50S WITH A BREEZY NORTH NORTHWEST WRAPAROUND FLOW UNDER CLOUDY SKIES. LIGHT RAIN WILL SLOWLY TAPER OFF FROM THE SOUTHWEST DURING THE DAY. HOWEVER OVER THE NORTHERN OUTER BANKS LIKELY POPS WILL CONTINUE THROUGH THE DAY. A SLIGHT CHANCE OF RAIN WILL LINGER IN THE EVENING OVER THE NORTHEAST COUNTIES AND ALONG THE OUTER BANKS AND SOUNDS. ALL RAIN WILL END SHORTLY AFTER MIDNIGHT AS THE LOW MOVES FURTHER AWAY AND DRIER AIR BEGINS TO WORK IN. DRY AND WARMER WEATHER IN STORE FOR THIS WEEKEND WITH RIDGING SURFACE AND ALOFT. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... SHORT TERM /THROUGH 12Z WEDNESDAY/... AS 630 AM TUESDAY...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS AFTN WITH INCREASING AND THICKENING CLOUD COVER DURING THE DAY. MVFR CIGS AND VSBYS LIKELY THIS EVENING WITH RAIN DEVELOPING. SOME IFR CONDITIONS PSBL NEAR COAST WITH HEAVIER PCPN THREAT. LONG TERM /WED THROUGH SAT/ AS OF 330 AM TUE...SCATTERED SHOWERS WILL SLOWLY TAPER OFF FROM THE SOUTHWEST DURING THE DAY WEDNESDAY AS LOW PRESSURE OFF THE NORTH COAST MOVES AWAY. NORTH NORTHWEST WINDS WILL START OUT AT 15-20 KNOTS THEN SLOWLY DIMINISH TO 10-15 IN THE AFTERNOON. DRY CONDITIONS AND LIGHT WINDS EXPECTED BEGINNING WEDNESDAY NIGHT AND CONTINUING INTO THE WEEKEND WITH HIGH PRESSURE AT THE SURFACE AND ALOFT BUILDING IN FROM THE WEST. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 940 AM TUESDAY...WINDS SHOULD RAMP UP OVER THE NEXT SEVERAL HOURS AS LOW PRESSURE OFFSHORE SLOWLY INTENSIFIES AS UPPER ENERGY DIVES INTO THE DEEP SOUTH. WINDS ALREADY GUSTING INTO THE LOWER 20S OVER THE PAMLICO SOUND AND AT THE BUOY OFF OF OREGON INLET. HAVE MADE SOME MINOR ADJUSTMENTS TO THE MARINE FORECAST BUT OVERALL ADVISORIES WILL REMAIN THE SAME. LONG TERM /WED THROUGH SAT/ AS OF 330 AM TUE...ECMWF BETTER THAN THE GFS OR NAM WHEN MATCHED UP WITH HPC SURFACE GRAPHICS...SO HAVE USED THE ECMWF AS THE BASIS FOR THE WIND FORECAST. GALES/SMALL CRAFT CONDITIONS WILL BE ONGOING WEDNESDAY. WAVE HEIGHTS WILL PEAK IN THE WATERS NORTH OF CAPE HATTERAS WEDNESDAY AND WEDNESDAY EVENING AT AROUND 9-11 FEET. GRADUAL IMPROVEMENT SEEN GOING INTO THURSDAY AND FRIDAY WITH CONDITIONS IMPROVING FROM SOUTH TO NORTH AS HIGH PRESSURE AT THE SURFACE AND ALOFT BUILDS IN FROM THE WEST RESULTING IN LIGHT WINDS AND SEAS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST THURSDAY FOR AMZ135. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST THURSDAY FOR AMZ130. GALE WARNING FROM 1 AM WEDNESDAY TO 1 AM EST THURSDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 PM EST THURSDAY FOR AMZ156-158. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...HSA AVIATION...JBM/HSA MARINE...JBM/CTC/HSA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1004 PM EST WED NOV 7 2012 .SYNOPSIS... LOW PRESSURE CENTER MOVED TO SOUTHEAST STATES WEDNESDAY AND WILL CONTINUE TO SHIFT SOUTHEASTWARD AND OUT OF OUR REGION WEDNESDAY NIGHT. THE LOW WILL BRING SOME CLOUDS TO EASTERN PART OF FORECAST AREA TONIGHT. HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION AND CONTINUE THROUGH FRIDAY. THIS WILL BRING DRY CONDITIONS FOR THE REMAINDER OF THE WEEK AND A WARMING TREND TOWARD THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... HAVE BEEN CLOSELY MONITORING TEMPS THIS EVENING AS WE ARE AGGRESSIVELY BELOW STATISTICAL MOS GUIDANCE ON OVERNIGHT LOWS. TEMPS INDEED HAVE FALLEN QUICKLY EARLY THIS EVENING WITH SOME NEAR FREEZING TEMPS ALREADY OCCURRING IN WCNTL OH/ECNTL IN. THUS...THINK TEMPS IN THE FORECAST IN GOOD SHAPE GIVEN AMPLE CLEARING ON EARLY EVENING SATELLITE LOOPS AND WINDS GOING LIGHT/CALM AS BOUNDARY LAYER DECOUPLES. A LITTLE CONCERNED ABOUT THE LIGHT FOG/HAZE ALREADY AT SOME SPOTS /5-7SM/ AND TEMP/DWPT SPREADS NEAR 5F SO EARLY IN THE EVENING...WILL MONITOR FOR A POTENTIAL INCLUSION OF THICKER/WIDESPREAD FOG TO THE FORECAST BEFORE 04Z. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... SURFACE RIDGING WILL REMAIN IN PLACE THROUGH FRIDAY. MID LEVEL HEIGHTS WILL GRADUALLY RISE DURING THIS TIME PERIOD. THIS PATTERN WILL BRING MOSTLY CLEAR SKIES AND LIGHT WINDS THROUGH FRIDAY. THURSDAYS HIGHS SHOULD BE A FEW DEGREES WARMER THAN WEDNESDAYS AS HEIGHTS RISE ACROSS THE AREA RESULTING IN WARMER AIR ALOFT. THIS WOULD RESULT IN A RETURN TO NEAR NORMAL HIGH TEMPERATURES THURSDAY...IN THE LOW TO MIDDLE 50S. FORECAST SLIGHTLY WARMER THAN GUIDANCE. DRY AIR WILL REMAIN IN PLACE THURSDAY NIGHT AND EXPECT LOW TEMPERATURES TO AGAIN BE BELOW GUIDANCE. BY FRIDAY...OUR AREA WILL BE ON THE WESTERN SIDE OF THE SURFACE HIGH PRESSURE SYSTEM. THE COMBINATION OF LIGHT RETURN FLOW AND WARMING ALOFT WILL RESULT IN MUCH WARMER DAYTIME TEMPERATURES. WENT ABOVE GUIDANCE FOR HIGHS AND MADE A FEW MINOR CHANGES TO CURRENT FORECAST. FRIDAY NIGHT...THE OHIO VALLEY REGION WILL CONTINUE TO BE ON THE WESTERN SIDE OF THE HIGH PRESSURE SYSTEM WITH WARM AIR ADVECTION. DRY CONDITIONS WILL CONTINUE AND LOW TEMPERATURES WILL BE ALMOST 10 DEGREES WARMER THAN THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... PERIOD WILL START OUT WARM AND DRY ON SATURDAY WITH THE AREA UNDER A RIDGE OF HIGH PRESSURE AND A SOUTHERLY SURFACE FLOW. A WEAK DISTURBANCE IN THE WARM SECTOR WILL PROBABLY PRODUCE NOTHING MORE THAN INCREASING CLOUDS SATURDAY AFTERNOON. SUNDAY LOOKS TO BE DRY AS WELL WITH THE RIDGE STILL IN CONTROL AS IT MOVES EAST OF THE REGION. WEATHER WILL CHANGE ABRUPTLY MONDAY WHEN A STRONG COLD FRONT IS FORECAST TO ENTER FROM THE WEST. SINCE MODEL UNCERTAINTY IS DECREASING AS WE GET CLOSER TO THE EVENT...WENT WITH SHOWERS LIKELY WITH A SLIGHT CHANCE OF THUNDERSTORMS FOR MONDAY INTO MONDAY NIGHT. WITH MODELS INDICATING MARGINAL ELEVATED CAPE...CHANCE OF THUNDER IS LOW BUT GREATER THAN ZERO. IT WILL BE BREEZY IN THE TIGHT PRESSURE GRADIENT ASSOCIATED WITH THE FRONT...WITH GUSTS AROUND 25 KNOTS EXPECTED. CONDITIONS WILL DRY OUT RAPIDLY BY LATE TUESDAY IN THE MARKEDLY COOLER AIRMASS BEHIND THE FRONT...WITH A LARGE AREA OF HIGH PRESSURE FORECAST TO MOVE IN AT THE SURFACE ON A WESTERLY FLOW ALOFT. THE HIGH WILL MAINTAIN THE DRY WEATHER THROUGH WEDNESDAY AS IT CROSSES THE AREA. TEMPERATURES WILL START OUT ABOVE NORMAL SATURDAY THROUGH MONDAY WITH HIGHS FORECAST TO BE IN THE 60S. A SHARP COOLING TREND WILL BE NOTED ON TUESDAY AND WEDNESDAY WHEN HIGHS WILL FALL BELOW NORMAL INTO THE 40S. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... CONTINUED TRENDS OF MAINLY VFR CONDITIONS AT THE TAF SITES...BUT DID INTRODUCE MVFR VSBYS AT KDAY LATER ON...BASED ON A MUCH LOWER TEMP/DWPT SPREAD HERE VERSUS OTHER TAF SITES. 07.22Z RAP ALSO MUCH MORE AGGRESSIVE IN BOUNDARY LAYER SATURATION AT THIS SITE...AND WHEN COUPLED WITH LAMP/MOS INDICATIONS...WAS ENOUGH TO INTRODUCE A PERIOD OF MVFR VSBYS. OTHERWISE...LIGHT NLY FLOW WILL BECOME VARIABLE WITH TIME AS BOUNDARY LAYER DECOUPLES AND PRETTY STRONG INVERSION SETS UP. SCT-BKN 20KFT CIRRUS HAS BEEN TRYING TO ADVECT WESTWARD INTO CNTL OH BUT ERODES ON THE LEADING EDGE THUS JUST SCT CIRRUS IN THE CMH/LCK TERMINALS IN THE EARLY EVENING. ON THURSDAY...START TO SWING THE SFC FLOW AROUND TO THE NW AND THEN SW THROUGH THE AFTN AS WE GET PAST THE SFC RIDGE AXIS. PLENTY OF SUN AND CONTINUED VFR CONDITIONS. .OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...PARKER NEAR TERM...BINAU SHORT TERM...PARKER LONG TERM...CONIGLIO AVIATION...BINAU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
713 PM EST WED NOV 7 2012 .SYNOPSIS... LOW PRESSURE CENTER MOVED TO SOUTHEAST STATES WEDNESDAY AND WILL CONTINUE TO SHIFT SOUTHEASTWARD AND OUT OF OUR REGION WEDNESDAY NIGHT. THE LOW WILL BRING SOME CLOUDS TO EASTERN PART OF FORECAST AREA TONIGHT. HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION AND CONTINUE THROUGH FRIDAY. THIS WILL BRING DRY CONDITIONS FOR THE REMAINDER OF THE WEEK AND A WARMING TREND TOWARD THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AN UPPER LEVEL LOW CENTERED OVER THE SOUTHEAST/MID ATLANTIC REGION BECOMES ABSORBED INTO ANOTHER UPPER LEVEL LOW/NOR`EASTER OFF THE MID ATLANTIC COAST. THE NOR`EASTER WILL MOVE NE ALONG THE EAST COAST TONIGHT AS UPPER LEVEL RIDGING BEGINS TO BUILD INTO THE OHIO RIVER VALLEY REGION. CLOUDS WILL CONTINUE TO SLOWLY MOVE OUT OF THE EXTREME SOUTHWEST PART OF FORECAST AREA THROUGH THIS EVENING. MEANWHILE...SOME HIGH CLOUDS ASSOCIATED WITH THE NOR`EASTER WILL SPREAD INTO THE EASTERN PART OF THE FORECAST AREA THROUGH THIS EVENING BEFORE THE LOW PULLS TO THE NE AND THE CLOUDS DECREASE. SURFACE HIGH PRESSURE WILL THEN BUILD INTO THE REGION. EXPECT ANY CLOUDS THAT MOVE INTO THE REGION THIS EVENING TO DECREASE TONIGHT AS HIGH PRESSURE AND DRIER AIR MOVES IN. TEMPERATURES SHOULD DROP INTO THE 20S TONIGHT. CONTINUED TO FORECAST LOWER THAN GUIDANCE AND ONLY MADE MINOR TWEAKS TO CURRENT FORECAST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... SURFACE RIDGING WILL REMAIN IN PLACE THROUGH FRIDAY. MID LEVEL HEIGHTS WILL GRADUALLY RISE DURING THIS TIME PERIOD. THIS PATTERN WILL BRING MOSTLY CLEAR SKIES AND LIGHT WINDS THROUGH FRIDAY. THURSDAYS HIGHS SHOULD BE A FEW DEGREES WARMER THAN WEDNESDAYS AS HEIGHTS RISE ACROSS THE AREA RESULTING IN WARMER AIR ALOFT. THIS WOULD RESULT IN A RETURN TO NEAR NORMAL HIGH TEMPERATURES THURSDAY...IN THE LOW TO MIDDLE 50S. FORECAST SLIGHTLY WARMER THAN GUIDANCE. DRY AIR WILL REMAIN IN PLACE THURSDAY NIGHT AND EXPECT LOW TEMPERATURES TO AGAIN BE BELOW GUIDANCE. BY FRIDAY...OUR AREA WILL BE ON THE WESTERN SIDE OF THE SURFACE HIGH PRESSURE SYSTEM. THE COMBINATION OF LIGHT RETURN FLOW AND WARMING ALOFT WILL RESULT IN MUCH WARMER DAYTIME TEMPERATURES. WENT ABOVE GUIDANCE FOR HIGHS AND MADE A FEW MINOR CHANGES TO CURRENT FORECAST. FRIDAY NIGHT...THE OHIO VALLEY REGION WILL CONTINUE TO BE ON THE WESTERN SIDE OF THE HIGH PRESSURE SYSTEM WITH WARM AIR ADVECTION. DRY CONDITIONS WILL CONTINUE AND LOW TEMPERATURES WILL BE ALMOST 10 DEGREES WARMER THAN THURSDAY NIGHT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... PERIOD WILL START OUT WARM AND DRY ON SATURDAY WITH THE AREA UNDER A RIDGE OF HIGH PRESSURE AND A SOUTHERLY SURFACE FLOW. A WEAK DISTURBANCE IN THE WARM SECTOR WILL PROBABLY PRODUCE NOTHING MORE THAN INCREASING CLOUDS SATURDAY AFTERNOON. SUNDAY LOOKS TO BE DRY AS WELL WITH THE RIDGE STILL IN CONTROL AS IT MOVES EAST OF THE REGION. WEATHER WILL CHANGE ABRUPTLY MONDAY WHEN A STRONG COLD FRONT IS FORECAST TO ENTER FROM THE WEST. SINCE MODEL UNCERTAINTY IS DECREASING AS WE GET CLOSER TO THE EVENT...WENT WITH SHOWERS LIKELY WITH A SLIGHT CHANCE OF THUNDERSTORMS FOR MONDAY INTO MONDAY NIGHT. WITH MODELS INDICATING MARGINAL ELEVATED CAPE...CHANCE OF THUNDER IS LOW BUT GREATER THAN ZERO. IT WILL BE BREEZY IN THE TIGHT PRESSURE GRADIENT ASSOCIATED WITH THE FRONT...WITH GUSTS AROUND 25 KNOTS EXPECTED. CONDITIONS WILL DRY OUT RAPIDLY BY LATE TUESDAY IN THE MARKEDLY COOLER AIRMASS BEHIND THE FRONT...WITH A LARGE AREA OF HIGH PRESSURE FORECAST TO MOVE IN AT THE SURFACE ON A WESTERLY FLOW ALOFT. THE HIGH WILL MAINTAIN THE DRY WEATHER THROUGH WEDNESDAY AS IT CROSSES THE AREA. TEMPERATURES WILL START OUT ABOVE NORMAL SATURDAY THROUGH MONDAY WITH HIGHS FORECAST TO BE IN THE 60S. A SHARP COOLING TREND WILL BE NOTED ON TUESDAY AND WEDNESDAY WHEN HIGHS WILL FALL BELOW NORMAL INTO THE 40S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... CONTINUED TRENDS OF MAINLY VFR CONDITIONS AT THE TAF SITES...BUT DID INTRODUCE MVFR VSBYS AT KDAY LATER ON...BASED ON A MUCH LOWER TEMP/DWPT SPREAD HERE VERSUS OTHER TAF SITES. 07.22Z RAP ALSO MUCH MORE AGGRESSIVE IN BOUNDARY LAYER SATURATION AT THIS SITE...AND WHEN COUPLED WITH LAMP/MOS INDICATIONS...WAS ENOUGH TO INTRODUCE A PERIOD OF MVFR VSBYS. OTHERWISE...LIGHT NLY FLOW WILL BECOME VARIABLE WITH TIME AS BOUNDARY LAYER DECOUPLES AND PRETTY STRONG INVERSION SETS UP. SCT-BKN 20KFT CIRRUS HAS BEEN TRYING TO ADVECT WESTWARD INTO CNTL OH BUT ERODES ON THE LEADING EDGE THUS JUST SCT CIRRUS IN THE CMH/LCK TERMINALS IN THE EARLY EVENING. ON THURSDAY...START TO SWING THE SFC FLOW AROUND TO THE NW AND THEN SW THROUGH THE AFTN AS WE GET PAST THE SFC RIDGE AXIS. PLENTY OF SUN AND CONTINUED VFR CONDITIONS. .OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...PARKER NEAR TERM...PARKER SHORT TERM...PARKER LONG TERM...CONIGLIO AVIATION...BINAU
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
544 PM MST WED NOV 7 2012 .DISCUSSION...00Z SURFACE ANALYSIS HAD COLD FRONT FROM NORTHEAST MT INTO SOUTH CENTRAL MT. 3-5MB/3HR PRESSURE RISES BEHIND IT...WHICH IS IN LINE WITH 21Z RAP. 21Z RAP HAS SOMEWHAT STRONGER WINDS BEHIND THE COLD FRONT FOR A FEW HOURS TONIGHT...SO WILL DO AN EARLY UPDATE TO ADDRESS. && .AVIATION...00Z TAFS VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY AFTERNOON. A COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT BRINGING NORTHWEST WINDS GUSTING TO 25KTS AT TIMES ACROSS THE SD PLAINS. && .PREV DISCUSSION... /ISSUED 249 PM MST WED NOV 7 2012/ DISCUSSION...CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHEAST WYOMING INTO SOUTHERN SASKATCHEWAN. WARM SOUTHERLY FLOW OVER THE AREA HAS PUSHED HIGHS INTO THE 70S OVER MANY LOCATIONS. UPPER LEVEL ANALYSIS PLACES RIDGE OVER THE CTRL CONUS...WITH AXIS STRETCHING FROM COLORADO/NEW MEXICO INTO THE WRN DAKOTAS. TONIGHT...RIDGE AXIS SHIFTS TO THE EAST WHILE COOL FRONT SETTLES INTO THE AREA. WINDS MAY BRIEFLY BECOME BREEZY IN THE WAKE OF THE FRONT...OTHERWISE QUIET WEATHER IS EXPECTED. ON THURSDAY...TEMPERATURES WILL BE NOTABLY COOLER IN THE WAKE OF THE FRONT...WITH HIGHS RETURNING CLOSER TO AVERAGE. SOUTHWEST FLOW SETS UP OVER THE AREA AHEAD OF POTENT UPPER LOW SLIDING OVER THE WEST COAST TOWARDS THE ROCKIES. WEAK WAVE SLIDING AHEAD OF THE LOW CROSSES THE AREA LATE IN THE EVE. FORECAST SOUNDINGS SUGGEST RAIN/FREEZING RAIN WILL BE POSSIBLE OVER FAR NWRN SD...THOUGH CHANCES REMAIN QUITE LOW. FOR FRIDAY...UPPER LOW/TROF CONTINUES TO PUSH OVER THE ROCKIES WITH PRECIP SLOWLY DEVELOPING FROM NW TO SE OVER THE AREA. IT APPEARS THAT MOST OF THE LIFT WITH THIS SYSTEM WILL REMAIN TO THE NORTH/WEST...THOUGH SOME PRECIP WILL DEVELOP OVER OUR AREA WITH STRONG ISENTROPIC LIFT...PARTICULARLY OVER THE NWRN CWA IN THE EVENING. THE FORECAST FOR PRECIP TYPE REMAINS TRICKY AS FORECAST SOUNDINGS SUGGEST THE POSSIBILITY OF SOME FREEZING RAIN OVER NWRN/W CTRL SD WITH WARMER AIR ALOFT...CHANGING TO SNOW AS COOLER AIR TRIES TO WORK IN AS COLD FRONT PUSHES IN LATE. EXTENDED...UPPER LEVEL TROF WILL MOVE ACROSS THE PLAINS OVER THE WEEKEND. UPPER LOW DEVELOPING WITHIN THE TROF IS GENERALLY PROGGED TO PASS TO THE NORTHWEST AND NORTH OF THE CWA SATURDAY INTO SUNDAY. SURFACE LOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WY FRIDAY...PASS JUST SOUTH OF THE FORECAST AREA ON SATURDAY...AND THEN MOVE WELL EAST OF THE AREA BY SUNDAY. AS THE LOW PASSES THROUGH THE REGION...A STRONG COLD FRONT WILL DRAG MUCH COLDER AIR INTO THE AREA...WITH TEMPERATURES SLOWLY FALLING ON SATURDAY. A BAND OF STRONG FRONTOGENESIS ALONG AND BEHIND THE FRONT WILL HELP TO PRODUCE THE BULK OF THE PCPN...MOSTLY IN THE FORM OF SNOW OR RAIN CHANGING TO SNOW. A BRIEF PERIOD OF FREEZING RAIN...POSSIBLY SLEET...LOOKS POSSIBLE ON SATURDAY ACROSS PORTIONS OF WESTERN SD DURING THE TRANSITION. BASED ON THE CURRENT TRACK...SNOW AMOUNTS DO NOT LOOK TO BE SIGNIFICANT FROM THIS SYSTEM...WITH UP TO AN INCH OVER FAR NORTHWEST SOUTH DAKOTA. PCPN WILL DIMINISH SATURDAY NIGHT...WITH MOST IF NOT ALL PCPN OUT OF THE AREA SUNDAY MORNING. DRY WEATHER IS THEN EXPECTED THROUGH EARLY NEXT WEEK. COLD TEMPERATURES WILL REMAIN ACROSS THE AREA SUNDAY...WITH MILDER AIR RETURNING EARLY NEXT WEEK...ESPECIALLY ACROSS SOUTHERN AND WESTERN PORTIONS OF THE CWA. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...HELGESON LONG TERM...WFO UNR AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
526 PM CST WED NOV 7 2012 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT 314 PM CST WED NOV 7 2012 AT 3 PM...A SURFACE RIDGE WAS LOCATED FROM THE CENTRAL PLAINS TO NORTH NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. ON THE EASTERN SIDE OF THIS RIDGE...LOW LEVEL MOISTURE /BELOW 900 MB/ REMAINS TRAPPED BELOW A SUBSIDENCE INVERSION. BOTH THE 07.12Z GFS AND NAM/WRF SUGGEST THAT AS THE WINDS PICK UP ON WESTERN SIDE OF THIS RIDGE...THE MOISTURE LIFTS AND EVENTUALLY MIXES OUT AS BECOMES PROGRESSIVELY THINNER. THESE MODELS SHOW THAT THIS WILL INITIALLY OCCUR ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS EVENING...AND SPREAD ACROSS WESTERN WISCONSIN AFTER MIDNIGHT. MEANWHILE THE LATEST RAP IS INSISTENT THAT THESE LOW CLOUDS WILL PERSIST THROUGH THE NIGHT. WITH THE SATELLITE SHOWING VERY LITTLE CLOUDS ON THIS ON THE WESTERN SIDE OF THE RIDGE...WENT ALONG WITH THE GFS AND NAM/WRF. HOWEVER A BIT CONCERNED THAT THAT THE TIME OF DAY WOULD FAVOR THE RAP SOLUTION. EVENING SHIFT WILL HAVE TO WATCH THIS CLOSELY. IF THE CLOUDS DO NOT CLEAR...THE LOW TEMPERATURES WILL BE ABOUT 5 TO 7 DEGREES TOO COLD. ON THURSDAY AFTERNOON AND NIGHT...THE 07.12Z MODELS ARE IN GOOD AGREEMENT THAT A PACIFIC COLD FRONT WILL MOVE EAST THROUGH THE FORECAST AREA. WITH THE SURFACE LOW MOVING THROUGH ONTARIO AND DRY AIR /290-300K CONDENSATION DEFICITS GREATER THAN 100 MB/ BEING ADVECTED OFF OF THE CENTRAL PLAINS AHEAD OF THIS SYSTEM...NOT EXPECTING TOO MUCH CLOUDS OR PRECIPITATION FROM THIS FRONT. ON FRIDAY AFTERNOON AND NIGHT...THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT WAVE TROUGH WILL EJECT OUT OF WESTERN UNITED STATES LONG WAVE TROUGH. AS THIS WAVES APPROACHES WEAK TO MODERATE 290-300K ISENTROPIC LIFT DEVELOPS OVER THE AREA. THE CONDENSATION DEFICITS SLOWLY DROP FROM OVER 100 MB ON FRIDAY AFTERNOON TO 20 TO 50 MBS BY SATURDAY MORNING. IN ADDITION...MODERATE 850 MB TRANSPORT WILL BE DEVELOPING ACROSS THE AREA ON FRIDAY NIGHT. THE NAM/WRF IS THE SLOWEST AT SATURATING THE ATMOSPHERIC COLUMN. AS A RESULT...IT DOES NOT GENERATE ANY PRECIPITATION UNTIL IT GETS OVER NORTHERN MINNESOTA AND FAR NORTHERN WISCONSIN. MEANWHILE THE GEM...GFS...AND ECMWF HAS THE PRECIPITATION DEVELOPING OVER OUR AREA. SINCE THE RUN TO RUN VARIABILITY HAS REMAINED INCONSISTENT... KEPT PRECIPITATION CHANCES IN THE 20 TO 40 PERCENT RANGE. WITH BOTH THE ECMWF AND NAM/WRF SUGGESTING MLCAPES WILL UP TO 400 J/KG ALONG AND NORTH OF THE WARM FRONT AFTER MIDNIGHT...ADDED ISOLATED THUNDERSTORMS TO THE FORECAST. .LONG TERM...SATURDAY THROUGH WEDNESDAY 314 PM CST WED NOV 7 2012 ON SATURDAY...THE 07.12Z MODELS ARE IN GOOD AGREEMENT THAT THE AREA WILL ENTER THE WARM SECTOR OF THE LOW PRESSURE SYSTEM. WHILE THIS IS THE CASE...THEY DO DIFFER ON THE STRENGTH OF THE CAP. THE NAM/WRF AND GEM HAVE THE STRONGEST CAP...THUS...NO PRECIPITATION. MEANWHILE THE GFS AND ECMWF SHOW A WEAKER CAP WHICH ALLOWS FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE THROUGHPUT THE DAY. SINCE THE MODELS HAVE VERY CONSISTENT WITH THIS TIME PERIOD...JUST KEPT THE PRECIPITATION CHANCES IN THE 20 TO 40 PERCENT RANGE. THIS PRECIPITATION ALSO AFFECTS THE AMOUNT OF INSTABILITY THAT CAN DEVELOP AHEAD OF THE APPROACHING COLD FRONT. WITH NO PRECIPITATION...THE MLCAPES CLIMB TO AROUND 600 J/KG IN THE NAM/WRF. MEANWHILE THE PRECIPITATION THE GFS AND ECMWF LIMITS THE MLCAPES TO LESS THAN 300 J/KG. THE 0-6 KM SHEAR IS FAVORABLE IN ALL 3 MODELS FOR MINI SUPERCELL DEVELOPMENT. HOWEVER A MAJORITY OF THIS SHEAR IS LOCATED IN THE 0-1 KM LAYER. IF THE THUNDERSTORMS DO NOT BECOME SURFACE BASED...THESE STORMS WILL ONLY HAVE LESS THAN 20 KNOTS OF SHEAR TO WORK WITH AND AS A RESULT THEY WOULD NOT HAVE ADEQUATE SHEAR TO ORGANIZE THEMSELVES INTO MINI SUPERCELLS. THE OTHER FORECAST CHALLENGE ON SATURDAY IS HOW WARM THE AREA WILL GET. 850 MB STANDARDIZED ANOMALIES ARE 1 TO 1.5 STANDARD DEVIATIONS ABOVE NORMAL. THE NAM/WRF HAS LITTLE CLOUDS IN THE WARM SECTOR WHICH ALLOWS THE HIGH TEMPERATURES TO RANGE FROM THE LOWER 60S TO LOWER 70S. MEANWHILE THE ECMWF HAS MORE CLOUD COVER AND ITS TEMPERATURES RANGE FROM THE LOWER 50S TO LOWER 70S. WITH SUCH UNCERTAINTY STAYED WITH THE ALL BLEND WHICH HAS HIGH TEMPERATURES RANGING FROM THE MID 50S TO UPPER 60S. FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE MODELS ARE IN GOOD AGREEMENT THAT A STRONG COLD FRONT WILL MOVE THROUGH THE REGION. STRONG PV ADVECTION AND FRONTOGENESIS WILL RESULT IN WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE AREA. WHILE THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE SHOWN SOME TIMING DIFFERENCES OVER THE PAST COUPLE OF DAYS...THUS...KEPT PRECIPITATION PROBABILITIES IN THE 55 TO 74 RANGE. TEMPERATURES IN THE WAKE OF THIS FRONT WILL QUICKLY FALL INTO THE 30S. SOUNDINGS ALOFT SUGGEST THAT THERE WILL BE SOME ICE CRYSTALS BEING INTRODUCED FROM ALOFT...THUS...SOME SNOW STILL LOOKS POSSIBLE FROM SUNDAY AFTERNOON INTO SUNDAY NIGHT. ANY ACCUMULATIONS WILL BE HIGHLY DEPENDENT UPON HOW FAST THIS RAIN TO SNOW TRANSITION OCCURS. FROM LATE SUNDAY NIGHT INTO MONDAY...IT APPEARS THAT THE 07.12Z MODELS ARE MUCH FASTER THAN THEIR PREDECESSORS AT MOVING THE PRECIPITATION OUT OF THE AREA. WANTED TO FOLLOW THEM...BUT COULD NOT GET ENOUGH CONSENSUS TO GO AWAY FROM THE ALL BLEND MODEL. && .AVIATION...TONIGHT AND THURSDAY 526 PM CST WED NOV 7 2012 BIGGEST CHALLENGE IN ON CLEARING POTENTIAL. LARGE AREA OF STRATUS SEEN ON SATELLITE IMAGERY WITH EDGE STILL OUT OVER SOUTH CENTRAL MINNESOTA. CEILING HEIGHTS ARE GENERALLY IN THE VFR CATEGORY. RAP 0-1KM RELATIVE HUMIDITY PROG HAS A GOOD HANDLE ON THE STRATUS. TREND IS FOR WESTERN EDGE TO ERODE AWAY AS PRESSURE GRADIENT BEGINS TO TIGHTEN LATER THIS EVENING...WITH INCREASING LOW LEVEL WINDS. FEEL KRST HAS THE BEST CHANCE OF BREAKING OUT THIS EVENING. HOWEVER...RAP SHOWS HIGH RH VALUES PERSISTING THROUGH MUCH OF THE NIGHT ALONG AND EAST OF THE MISSISSIPPI RIVER. THIS WILL BEAR WATCHING AS CLOUDS MAYBE SLOWER TO CLEAR AT KLSE. WILL HAVE TO WATCH TO SEE HOW THINGS PAN OUT THIS EVENING. FOR NOW WILL KEEP CLEARING TREND IN AT 05Z AT KRST AND 07Z AT KLSE. WITHIN THE STRATUS CEILINGS HEIGHTS WILL REMAIN IN THE VFR CATEGORY. ONCE CLOUDS CLEAR...VFR CONDITIONS WILL PERSIST. EXPECT SOME DECENT MIXING LATER THURSDAY MORNING...WITH SOUTHWEST WINDS GUSTING TO 20 TO 23 KNOTS AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 200 PM CST WED NOV 7 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
238 PM CST TUE NOV 6 2012 .SHORT TERM...TONIGHT THROUGH FRIDAY 238 PM CST TUE NOV 6 2012 THE MAIN FOCUS THROUGH FRIDAY IS WITH HOW LONG THE PRECIPITATION AND CLOUD COVER HOLDS ON FOR INTO WEDNESDAY ALONG WHERE A COLD FRONT WILL END UP THURSDAY INTO FRIDAY. CURRENTLY...A BAND OF RAIN AND SNOW WILL CONTINUE TO TRACK TO THE EAST TONIGHT AHEAD OF WHAT APPEARS TO BE A WARM FRONT RATHER THAN A COLD FRONT EXTENDING SOUTH ALONG THE MISSISSIPPI RIVER. A SURFACE LOW NEAR DULUTH WILL QUICKLY DROP TO THE SOUTHEAST WITH A RIDGE OF HIGH PRESSURE MOVING INTO THE CENTRAL PLAINS. IN THE UPPER LEVELS...AN AMPLIFIED PATTERN IS TAKING SHAPE WITH BROAD TROUGHING ALONG THE ATLANTIC COAST AND RIDGING ACROSS THE ROCKIES. THIS LEAVES THE UPPER MISSISSIPPI RIVER VALLEY IN NORTHWESTERLY FLOW ALOFT WITH COOL AIR COMING INTO THE REGION FROM CANADA. AS THE LOW DROPS DOWN TONIGHT IT WILL KEEP SOME HIGH AMOUNTS OF MOISTURE LOCKED IN THE LOW LEVELS WITH STEEP SURFACE TO 800MB LAPSE RATES BASED ON 06.12Z NAM/GFS AND 06.18Z RAP SOUNDINGS. WITH ENOUGH LOW LEVEL LIFT PERSISTING THROUGH THE NIGHT AND THE DEEP LOW LEVEL MOISTURE EXTENDING FROM NEAR THE SURFACE UP INTO THE -10C RANGE AROUND 10KFT...SOME RAIN AND SNOW SHOWERS WILL DEVELOP/MOVE IN WITH THE LOW THIS EVENING. THE DEPTH OF THE MOISTURE AND LIFT SLOWLY DECREASE OVERNIGHT AS THE SYSTEM MOVES INTO THE OHIO RIVER VALLEY WHICH MEANS THAT ICE WILL STOP BEING GENERATED AND THE THERMAL PROFILE BECOMES MORE FAVORABLE FOR DRIZZLE. ANY LOW LEVEL OMEGA APPEARS TO BE OUT OF THE REGION BY AROUND 12Z TOMORROW MORNING...SO THE DRIZZLE SHOULD END BY THEN. CONFIDENCE IS NOT HIGH WITH HOW LONG THE CLOUD COVER WILL HOLD ON FOR...BUT HAVE GONE THE PESSIMISTIC ROUTE UNTIL THE RIDGE GETS IN TOMORROW AFTERNOON. 06.12Z NAM/GFS SOUNDINGS DO INDICATE SOME MOISTURE REMAINING TRAPPED UNDER A SINKING INVERSION THAT DROPS TO AROUND 4KFT BY TOMORROW AFTERNOON. DUE TO THIS CLOUD COVER...HAVE KEPT OVERNIGHT LOWS UP A BIT ABOVE GUIDANCE AND THEN LOWERED THEM A FEW DEGREES TOMORROW. THE FOCUS THEN SHIFTS TO A COLD FRONT THAT WILL DROP DOWN INTO THE REGION AS A MID LEVEL SHORT WAVE TROUGH SKIRTS THE NORTHERN PERIPHERY OF THE RIDGE. THE CONSENSUS BETWEEN THE 06.12Z GUIDANCE IS TO BRING THE FRONT ACROSS CENTRAL WISCONSIN AND IOWA TO A SURFACE LOW IN EASTERN COLORADO BY FRIDAY MORNING. IT WILL THEN STALL AND TRANSITION TO BEING A WARM FRONT WITH LOW LEVEL WARM AIR ADVECTION KICKING IN AS THE LOW EJECTS INTO THE PLAINS. WENT DRY ON FRIDAY BUT WILL HAVE TO MONITOR AS THE 06.12Z GFS SHOWS ENOUGH DEPTH TO THE MOISTURE ALONG THE FRONT THAT A FEW SHOWERS OR DRIZZLE COULD DEVELOP. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY 238 PM CST TUE NOV 6 2012 THE MAIN FOCUS FOR NEXT WEEKEND IS WITH THE BROAD TROUGHING ALOFT THAT BRINGS A DEEPENING SURFACE LOW ACROSS MINNESOTA ON SATURDAY. PRECIPITATION SHOULD BECOME MORE WIDESPREAD FRIDAY NIGHT AS THE WARM AIR ADVECTION STRENGTHENS AHEAD OF THE LOW. SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF A COLD FRONT IN MINNESOTA ON SATURDAY WHERE 0-3KM MUCAPE INCREASES TO AROUND 1000 J/KG IN THE AFTERNOON. IT APPEARS THAT THE BETTER CHANCES FOR ANY SEVERE WEATHER WILL BE TO THE WEST NEAR THE TRACK OF THE SURFACE LOW AND AHEAD OF THE COLD FRONT. SOME INSTABILITY HOLDS ON INTO THE EVENING AND OVERNIGHT...BUT IS RATHER SKINNY AND WEAKENS AS THE NIGHT PROGRESSES. AFTER THE FRONT PASSES THROUGH EARLY ON SUNDAY...THE NEXT QUESTION IS WITH WHETHER OR NOT THE COLD AIR WILL GET IN FAST ENOUGH WITH THE PRECIPITATION STILL FALLING THAT IT WOULD CHANGE OVER FROM RAIN TO SNOW. THE 06.12Z GFS IS A BIT FASTER WITH ENDING THE PRECIPITATION ON SUNDAY WHILE THE 06.12Z ECMWF HOLDS ONTO IT A BIT LONGER WITH A LOW TO MID LEVEL BAND OF FRONTOGENESIS WHICH COULD END UP BEING MORE CONDUCIVE TO THE SNOW OCCURRING. TEMPERATURES WILL PLUMMET SUNDAY THROUGH TUESDAY AS 850MB TEMPERATURES DROP TO AROUND -12C WHICH WILL HELP TO KEEP TEMPERATURES IN THE 30S FOR HIGHS AND 20S FOR LOWS. && .AVIATION...THROUGH 18Z WEDNESDAY 1146 AM CST TUE NOV 6 2012 WATER VAPOR IMAGERY SHOW A VIGOROUS SHORT WAVE TROUGH MOVING SOUTHEAST THROUGH EASTERN MINNESOTA. THE 06.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT THIS SYSTEM WILL MOVE SOUTHEAST ALONG THE MISSISSIPPI RIVER THIS AFTERNOON. THIS SYSTEM WILL CONTINUE TO PRODUCE SCATTERED RAIN SHOWERS ACROSS THE AREA THROUGH THIS AFTERNOON. THE RAIN MAY MIX WITH SNOW AT TIMES ACROSS WISCONSIN. IN THE WAKE OF THIS SYSTEM...DRIZZLE WILL CONTINUE INTO TONIGHT. THINKING THAT ANY REDUCTIONS TO VISIBILITIES WILL MAINLY ALONG AND EAST OF INTERSTATE 94 THIS AFTERNOON. CEILINGS WILL BE MAINLY MVFR FROM THIS AFTERNOON THROUGH WEDNESDAY MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... 238 PM CST TUE NOV 6 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1147 AM CST TUE NOV 6 2012 .SHORT TERM...TODAY 1047 AM CST TUE NOV 6 2012 THE MESO MODELS HAVE COME IN COOLER THIS MORNING...SO LOWERED TEMPERATURES BY ABOUT 5 DEGREES ACROSS THE AREA. RAP SOUNDINGS SUGGEST THAT SOME LIGHT SNOW WILL BE POSSIBLE ACROSS WESTERN WISCONSIN THIS AFTERNOON. WITH SNOW RATES LESS THAN THEY WERE THIS MORNING...EXPECTING ADDITION SNOW AMOUNTS OF LESS THAN A HALF INCH. FURTHER WEST...WRAP AROUND PRECIPITATION WILL MOVE INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON. SINCE THERE IS GOOD CONSENSUS OF THIS OCCURRING IN THE MODELS...ADDED SOME PRECIPITATION CHANCES TO THESE AREAS. .LONG TERM...FRIDAY THROUGH MONDAY 328 AM CST TUE NOV 6 2012 06.00Z MEDIUM RANGE MODEL RUNS CONTINUE TO INDICATE A LONGWAVE TROUGH WILL MOVE INTO THE MIDDLE OF THE COUNTRY FOR THE DAY 4-7 PERIOD...BRINGING AN ACTIVE PERIOD OF WEATHER TO THE UPPER MIDWEST FOR THE WEEKEND INTO EARLY NEXT WEEK. HOWEVER...PLENTY OF DETAIL DIFFERENCES WITH THE TIMING/EVOLUTION OF VARIOUS SHORTWAVES TO ROTATE THROUGH THE TROUGH AND PASS OVER OR BY THE REGION SAT INTO MON. AGAIN...THESE DIFFERENCES NOT UNEXPECTED IN THE DAY 5-7 TIME- FRAME BUT THEY DO LOWER FCST CONFIDENCE INTO THE AVERAGE RANGE FOR THE LONG TERM. AS PREVIOUS FORECASTER STATED...THE QUESTION TO START THE EXTENDED PERIOD IS WITH HOW FAR SOUTH A COLD FRONT MAKES IT ON FRI BEFORE IT STALLS AND TRANSITIONS TO A WARM FRONT. LATEST MODELS TEND TO WASH OUT THIS BOUNDARY BY FRIDAY WITH A VERY BROAD TROUGH FROM THE EASTERN CO LOW INTO EASTERN WI ON FRI. GFS THE ONLY MODEL TO PRODUCE SOME LIGHT -RA OVER THE AREA FRI...AND IT TENDS TO BE TOO ROBUST WITH THIS IN CAPPED WARM SECTORS. GIVEN A DIFFUSE BOUNDARY AT BEST LEFT FRI DRY. FIRST SHORTWAVE OUT OF THE TROUGH DEVELOPS A RATHER STRONG LOW INTO MN BY LATE SAT...WITH THE AREA UNDER STRONG 925-850MB WARMING AHEAD OF IT. SAT STILL LOOKS TO BE A VERY WARM DAY FOR MID NOV HOWEVER THE LOW LEVEL JET AND GULF MOISTURE CONTINUE TO STREAM INTO THE AREA...UNDER AN INVERSION. EVEN IN THE WARM SECTOR...SAT LOOKING TO BE A MOSTLY CLOUDY DAY AS A 50-55 DEW POINT AIRMASS IS PUSHED NORTHWARD OVER LOW-MID 40S SOIL/WATER TEMPS. GFS/ECMWF CONTINUE TO INDICATE UP TO 250 J/KG OF MU CAPE OVER THE AREA SAT. WITH SOME LIFTING IN THE 850MB LAYER UNDER FALLING HGTS ALOFT...SMALL -SHRA/ TSRA CHANCE ON SAT STILL LOOKS REASONABLE. THE STRONG COLD FRONT STILL SLATED TO PUSH ACROSS THE AREA SAT NIGHT...INTO THE 250 J/KG CAPE AIRMASS. STRONG FORCING SIGNAL WITH AND BEHIND THE FRONT FOR SAT NIGHT INTO SUN. 40-70 PERCENT SHRA CHANCE THESE PERIODS LOOK GOOD. SMALL TSRA CHANCE CONTINUES AS WELL SAT NIGHT. SOLUTIONS LESS CLEAR-CUT FOR SUN NIGHT/MON AS THE MAIN TROUGH BEGINS TO LIFT OUT. LATEST RUNS MORE PROGRESSIVE WITH THIS PART OF THE TROUGH/SHORTWAVE ENERGY...TAKING THE BULK OF IT SOUTH/EAST OF THE FCST AREA. WITH AVERAGE CONFIDENCE AT BEST BY MON...DID NOT STRAY FROM THE MODEL/ENSEMBLE CONSENSUS ON DAY 7 FOR NOW. && .AVIATION...THROUGH 18Z WEDNESDAY 1146 AM CST TUE NOV 6 2012 WATER VAPOR IMAGERY SHOW A VIGOROUS SHORT WAVE TROUGH MOVING SOUTHEAST THROUGH EASTERN MINNESOTA. THE 06.12Z MODELS ARE IN VERY GOOD AGREEMENT THAT THIS SYSTEM WILL MOVE SOUTHEAST ALONG THE MISSISSIPPI RIVER THIS AFTERNOON. THIS SYSTEM WILL CONTINUE TO PRODUCE SCATTERED RAIN SHOWERS ACROSS THE AREA THROUGH THIS AFTERNOON. THE RAIN MAY MIX WITH SNOW AT TIMES ACROSS WISCONSIN. IN THE WAKE OF THIS SYSTEM...DRIZZLE WILL CONTINUE INTO TONIGHT. THINKING THAT ANY REDUCTIONS TO VISIBILITIES WILL MAINLY ALONG AND EAST OF INTERSTATE 94 THIS AFTERNOON. CEILINGS WILL BE MAINLY MVFR FROM THIS AFTERNOON THROUGH WEDNESDAY MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... 328 AM CST TUE NOV 6 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....RRS AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1049 AM CST TUE NOV 6 2012 .SHORT TERM...TODAY 1047 AM CST TUE NOV 6 2012 THE MESO MODELS HAVE COME IN COOLER THIS MORNING...SO LOWERED TEMPERATURES BY ABOUT 5 DEGREES ACROSS THE AREA. RAP SOUNDINGS SUGGEST THAT SOME LIGHT SNOW WILL BE POSSIBLE ACROSS WESTERN WISCONSIN THIS AFTERNOON. WITH SNOW RATES LESS THAN THEY WERE THIS MORNING...EXPECTING ADDITION SNOW AMOUNTS OF LESS THAN A HALF INCH. FURTHER WEST...WRAP AROUND PRECIPITATION WILL MOVE INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON. SINCE THERE IS GOOD CONSENSUS OF THIS OCCURRING IN THE MODELS...ADDED SOME PRECIPITATION CHANCES TO THESE AREAS. .LONG TERM...FRIDAY THROUGH MONDAY 328 AM CST TUE NOV 6 2012 06.00Z MEDIUM RANGE MODEL RUNS CONTINUE TO INDICATE A LONGWAVE TROUGH WILL MOVE INTO THE MIDDLE OF THE COUNTRY FOR THE DAY 4-7 PERIOD...BRINGING AN ACTIVE PERIOD OF WEATHER TO THE UPPER MIDWEST FOR THE WEEKEND INTO EARLY NEXT WEEK. HOWEVER...PLENTY OF DETAIL DIFFERENCES WITH THE TIMING/EVOLUTION OF VARIOUS SHORTWAVES TO ROTATE THROUGH THE TROUGH AND PASS OVER OR BY THE REGION SAT INTO MON. AGAIN...THESE DIFFERENCES NOT UNEXPECTED IN THE DAY 5-7 TIME- FRAME BUT THEY DO LOWER FCST CONFIDENCE INTO THE AVERAGE RANGE FOR THE LONG TERM. AS PREVIOUS FORECASTER STATED...THE QUESTION TO START THE EXTENDED PERIOD IS WITH HOW FAR SOUTH A COLD FRONT MAKES IT ON FRI BEFORE IT STALLS AND TRANSITIONS TO A WARM FRONT. LATEST MODELS TEND TO WASH OUT THIS BOUNDARY BY FRIDAY WITH A VERY BROAD TROUGH FROM THE EASTERN CO LOW INTO EASTERN WI ON FRI. GFS THE ONLY MODEL TO PRODUCE SOME LIGHT -RA OVER THE AREA FRI...AND IT TENDS TO BE TOO ROBUST WITH THIS IN CAPPED WARM SECTORS. GIVEN A DIFFUSE BOUNDARY AT BEST LEFT FRI DRY. FIRST SHORTWAVE OUT OF THE TROUGH DEVELOPS A RATHER STRONG LOW INTO MN BY LATE SAT...WITH THE AREA UNDER STRONG 925-850MB WARMING AHEAD OF IT. SAT STILL LOOKS TO BE A VERY WARM DAY FOR MID NOV HOWEVER THE LOW LEVEL JET AND GULF MOISTURE CONTINUE TO STREAM INTO THE AREA...UNDER AN INVERSION. EVEN IN THE WARM SECTOR...SAT LOOKING TO BE A MOSTLY CLOUDY DAY AS A 50-55 DEW POINT AIRMASS IS PUSHED NORTHWARD OVER LOW-MID 40S SOIL/WATER TEMPS. GFS/ECMWF CONTINUE TO INDICATE UP TO 250 J/KG OF MU CAPE OVER THE AREA SAT. WITH SOME LIFTING IN THE 850MB LAYER UNDER FALLING HGTS ALOFT...SMALL -SHRA/ TSRA CHANCE ON SAT STILL LOOKS REASONABLE. THE STRONG COLD FRONT STILL SLATED TO PUSH ACROSS THE AREA SAT NIGHT...INTO THE 250 J/KG CAPE AIRMASS. STRONG FORCING SIGNAL WITH AND BEHIND THE FRONT FOR SAT NIGHT INTO SUN. 40-70 PERCENT SHRA CHANCE THESE PERIODS LOOK GOOD. SMALL TSRA CHANCE CONTINUES AS WELL SAT NIGHT. SOLUTIONS LESS CLEAR-CUT FOR SUN NIGHT/MON AS THE MAIN TROUGH BEGINS TO LIFT OUT. LATEST RUNS MORE PROGRESSIVE WITH THIS PART OF THE TROUGH/SHORTWAVE ENERGY...TAKING THE BULK OF IT SOUTH/EAST OF THE FCST AREA. WITH AVERAGE CONFIDENCE AT BEST BY MON...DID NOT STRAY FROM THE MODEL/ENSEMBLE CONSENSUS ON DAY 7 FOR NOW. && .AVIATION...TODAY AND TONIGHT 527 AM CST TUE NOV 6 2012 AREA OF MAINLY LIGHT RAIN CONTINUES TO MAKE STEADY EASTWARD PROGRESS WITH THE REGIONAL COMPOSITE RADAR ALREADY SHOWING THE BACK EDGE APPROACHING THE I35 CORRIDOR. CEILINGS IN THE PRECIPITATION WILL BE PROBLEMATIC WITH KLSE DOWN IN THE VALLEY EXPECTED TO REMAIN MVFR WHILE KRST ON THE HIGHER TERRAIN TO BE IFR. THE VISIBILITY IN THE PRECIPITATION WILL BE MVFR. THE PRECIPITATION LOOKS LIKE IT SHOULD END IN KRST BY MID MORNING AND AROUND 18Z FOR KLSE. ONCE THE PRECIPITATION ENDS...LOOK FOR THE VISIBILITY TO COME UP TO VFR WITH MVFR CEILINGS. THE COLD FRONT WITH THE PRECIPITATION IS BACK ACROSS WESTERN MINNESOTA INTO NORTHWEST IOWA AND THIS SHOULD COME THROUGH BY EARLY AFTERNOON IN KRST AND MID AFTER AT KLSE SWINGING THE WINDS AROUND TO THE WEST/NORTHWEST. THE MIXING BEHIND THE FRONT LOOKS TO BE DEEP ENOUGH TO PRODUCE SOME WIND GUSTS TO AROUND 20 KNOTS AT KRST. THE CLOUDS ARE EXPECTED TO REMAIN OVER BOTH TAF SITES THROUGH THE NIGHT WITH MVFR CEILINGS WITH CLEARING TAKING PLACE AFTER 12Z WEDNESDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 328 AM CST TUE NOV 6 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....RRS AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CST MON NOV 5 2012 .SHORT TERM... 928 PM CST MON NOV 5 2012 GOES WATER VAPOR IMAGERY UPSTREAM OVER SOUTHERN CANADA SHOWING TWO IMPULSES WITH A NICE SIGNAL OF DARKENING JUST WEST OF LAKE WINNIPEG AT 02Z. THIS DARKENING WAS ASSOCIATED WITH A RAP-ANALYZED TROPOPAUSE FOLD DOWN TO 600 MB. SOME ADDITIONAL DARKENING ASSOCIATED WITH THE INITIAL VORTICITY ADVECTION IN THE TROUGH IN ERN SD AS WELL. THIS LEAD TROUGH IS CAUSING SOME ELEVATED ECHO OVER MN/SD WITH VERY LITTLE PRECIPITATION BEING OBSERVED. THE LOCAL AREA WILL TAKE A DIRECT HIT FROM THE SECOND STRONG SHORTWAVE TROUGH NEAR LAKE WINNIPEG BASED ON FORECAST MODEL CONSENSUS. THIS HAS DEVELOPED A MORE N-S BAND OF ECHO ALONG THE ERN ND BORDER EXTENDING NORTH INTO MANITOBA WITH A FEW HUNDREDTHS OF PRECIPITATION PER HOUR BEING REPORTED. QG ANALYSIS TAKES THE LIFT FROM THESE DYNAMICS RIGHT ACROSS THE FORECAST AREA IN THE 06.00 AND 05.18 NAM...LATEST RAP FORECASTS...AND 05.18 GFS. HAVE INCREASED PRECIPITATION CHANCES TO 80 PERCENT IN MOST AREAS. SOME QUESTION ON THE PRECIPITATION TYPE AS THE CLOUDS HAVE HELD FIRM OVER SERN MN...AND SLIPPED A BIT EAST INTO NW WI. OTHERWISE...TEMPERATURES WERE REALLY COOLING IN MOST OF EXTREME NERN IA...SWRN AND CENTRAL WI UNDER CLEAR SKIES. ONCE THE CLOUD COMES OVER...EVEN THOUGH IT IS 8KFT...TEMPERATURES WARM RAPIDLY 3-4F. FOR CENTRAL WI INTO SWRN WI...WITH THICKER CLOUDS EXPECTED JUST PRIOR TO PRECIPITATION ONSET...TEMPERATURES AND WETBULB TEMPERATURES WOULD SEEM TO SUPPORT A BIT OF SNOW ACCUMULATION /IN ADDITION TO I-94/NORTHEAST ACCUM AREA FROM PREV FORECAST/. WITH WARM SOILS OF 40F OR MORE AT 2 INCHES...STILL THINK ACCUMULATION DIFFICULT. BUT...WHERE IT IS THE COLDEST TONIGHT WILL FAVOR SOME...GENERALLY 1/2 INCH OR LESS. 06.00Z NAM SNOW DEPTH...WHICH MODELS THE LAND SURFACE HEAT FLUXES...PLACED 0.3 INCHES OF SNOW ACCUM IN THAT REGION...RICHLAND/ERN VERNON COUNTY/MONROE AREA. AN OUTSIDE CHANCE OF VERY BRIEF FZRA IS POSSIBLE FOR ANY SITE REMAINING 32F OR BELOW...AND MAINLY JUST EAST OF THE MISS RIVER WHERE THE TOP OF THE INVERSION WOULD BE WARM ENOUGH TO MELT INCOMING ICE. HAVE NOT ADDED THIS TO THE FORECAST BUT WE WILL MONITOR AS IT APPROACHES LATER TONIGHT. IT MAY NEED A SPECIAL WEATHER STATEMENT. A CHANGE TO SNOW WOULD QUICKLY RESULT AS THE THERMAL PROFILE GOES TO THE WET-BULB NEAR 0C. FORECAST UPDATES ARE OUT. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY 304 PM CST MON NOV 5 2012 AN ACTIVE PERIOD IS ON TAP FOR THE WEEKEND INTO EARLY NEXT WEEK AS BROAD UPPER LEVEL TROUGHING PROPAGATES EAST ACROSS THE ROCKIES ON INTO THE CENTRAL US AND GREAT LAKES REGION. THE QUESTION TO START THE EXTENDED PERIOD IS WITH HOW FAR SOUTH A COLD FRONT MAKES IT ON FRIDAY BEFORE IT STALLS OUT AND TRANSITIONS TO A WARM FRONT. THE 05.12Z ECMWF IS TRENDING TOWARD WHAT THE GFS HAS ADVERTISED THE PAST FEW DAYS WITH A MORE SOUTHERN SOLUTION. BY 00Z SATURDAY...THE FRONT WILL START NEAR A SURFACE LOW IN EASTERN COLORADO AND RUN EAST THROUGH NORTHWEST IOWA AND CENTRAL WISCONSIN. THE 05.12Z GFS SHOWS SOME PRECIPITATION DEVELOPING ALONG THIS FRONT FRIDAY NIGHT AS THE LOW LEVEL JET KICKS IN AND NOSES UP INTO THE REGION WHILE THE 05.12Z ECMWF/GEM KEEP IT DRY WITH THE FOCUS A BIT FURTHER NORTH. A LOW PRESSURE SYSTEM WILL THEN DEVELOP IN THE LEE OF THE ROCKIES ALONG THIS FRONT AND TRACK NORTHEAST ALONG THE FRONT AND DEEPEN INTO MINNESOTA ON SATURDAY/SATURDAY NIGHT WITH THE 05.12Z GFS/ECMWF IN DECENT AGREEMENT ON THIS SCENARIO. THIS TRACK WILL LEAD TO SATURDAY BEING THE WARMEST DAY OF THE WEEK WITH TEMPERATURES GETTING INTO THE 60S. AS A RESULT OF THIS RELATIVELY WARM AND MOIST AIR MASS GETTING IN...THERE APPEARS TO BE SOME WEAK INSTABILITY THAT DEVELOPS AHEAD OF THE FRONT SO THERE COULD BE A FEW THUNDERSTORMS THAT DEVELOP THOUGH TIMING DOES NOT LOOK FAVORABLE FOR ANYTHING SEVERE. THE FRONT THEN SLOWLY TRACKS TO THE EAST ON SUNDAY WITH PRECIPITATION LIKELY FORMING ALONG AND BEHIND IT. WITH STRONG LOW LEVEL COLD AIR ADVECTION BEHIND THE FRONT...IT APPEARS THAT TEMPERATURES WILL BE ABLE TO COOL ENOUGH FOR THE RAIN TO TRANSITION TO SNOW FOR A PERIOD. THEN...THERE IS THEN CONTINUED GOOD AGREEMENT BETWEEN THE 05.12Z GFS/ECMWF FOR THE BELLY OF THE MID LEVEL TROUGH TO BECOME NEGATIVELY TILTED ON MONDAY WITH A DEEPENING SURFACE LOW RUNNING UP THE COLD FRONT THROUGH CHICAGO. THERMAL PROFILES WOULD BE COLD ENOUGH FOR THE PRECIPITATION TYPE TO BE ALL SNOW...SO THE TRENDS WITH THIS SYSTEM WILL HAVE TO BE MONITORED SINCE THE TRACK WOULD DICTATE WHERE THE HEAVIEST SNOW WOULD FALL. RIGHT NOW...THE 05.12Z GFS IS FASTER WITH THE SURFACE LOW NEAR SOUTHERN LAKE MICHIGAN BY 18Z MONDAY WHILE THE 05.12Z ECMWF GETS IT THERE AROUND 6Z TUESDAY. && .AVIATION...THROUGH 06Z WEDNESDAY 1147 PM CST MON NOV 5 2012 HAVE ADJUSTED LATEST TAFS TO INCLUDE IFR CONDITIONS AT KRST FOR INCOMING WEATHER SYSTEM. THIS WEATHER SYSTEM IS PRODUCING PRECIPITATION ACROSS NWRN MN WITH ITS LEADING EDGE APPROACHING CENTRAL MN AT THIS TIME. CONFIDENCE IS HIGH ON PRECIPITATION AFFECTING BOTH SITES FOR 4-5 HOURS. WITH COLDER AIR IN PLACE AT KLSE...SNOW IS A POSSIBILITY...MIXED WITH RAIN. HAVE INCLUDED SNRA AT KLSE WITH MVFR CIGS/VSBYS. PRECIPITATION SHOULD BE PROGRESSIVE WITH IMPROVING CONDITIONS TO VFR OR HIGHER MVFR AS AFTERNOON PROGRESSES. A LARGE CLOUD SHIELD WILL THEN SPREAD IN FROM THE NORTH TUESDAY NIGHT WITH MVFR CONDITIONS EXPECTED AT BOTH SITES. && .ARX WATCHES/WARNINGS/ADVISORIES... 304 PM CST MON NOV 5 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM...HALBACH AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1231 AM EST THU NOV 8 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST TONIGHT INTO FRIDAY THEN PERSIST OVER THE WEEKEND. A WEAK COASTAL TROUGH MAY FORM NEARBY EARLY NEXT WEEK...AS THE HIGH BEGINS TO SHIFT EAST. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SKIES HAVE CLEARED AND THE BOUNDARY LAYER HAS DECOUPLED WITH A STRONG NOCTURNAL INVERSION NOTED ON REGIONAL RAP FORECAST SOUNDINGS. ALTHOUGH WINDS ATOP THE BOUNDARY LAYER ARE FORECAST TO INCREASE OVERNIGHT WITH THE APPROACH OF A SECONDARY VORTICITY OVER SOUTHWEST VIRGINIA...MODEL SOUNDINGS SUGGEST THE NOCTURNAL INVERSION WILL LIKELY REMAIN STRONG ENOUGH TO PREVENT A FULL RECOUPLING OF THE BOUNDARY LAYER. BUFKIT MIXING PROFILES ONLY SUPPORT 5 KT OF MIXED LAYER WIND THROUGH SUNRISE. THE COMBINATION OF LIGHT WINDS AND CLEAR SKIES WILL PROMOTE STRONG RADIATIONAL COOLING FOR MANY AREAS TONIGHT. SHOULD SEE LOWS DROP INTO MID 30S WELL INLAND WITH LOWER 40S NEAR THE COAST. COULD EVEN SEE A FEW AREAS APPROACH THE FREEZING MARK IN SOME OF THE NORMALLY COLDER SPOTS SUCH AS ALLENDALE...ROCKY FORD AND JAMESTOWN...BUT THE SITUATION LOOKS TOO MARGINAL FOR A FREEZE WARNING. THERE WILL BE A RISK FOR FROST TONIGHT. CONDITIONS WILL BE THE MOST FAVORABLE FOR SCATTERED FROST ROUGHLY ALONG AND NORTH OF AN ALLENDALE-HAMPTON-WALTERBORO-SUMMERVILLE-JAMESTOWN LINE. A FROST ADVISORY IS IN EFFECT FOR THESE AREAS. MIDNIGHT OBSERVATIONS ALSO SHOW SOME COLDER POCKETS IN SE GEORGIA LIKE STATESBORO AND SYLVANIA AND THERE COULD BE LOCALIZED AREAS OF FROST ALONG/NEAR THE I-16 CORRIDOR IN SE GEORGIA. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... SURFACE HIGH PRESSURE WILL SHIFT EAST ACROSS THE AREA THIS PERIOD WITH DRY AND UNSEASONABLY COOL CONDITIONS EXPECTED...ESPECIALLY THROUGH FRIDAY NIGHT. THE BIGGEST CONCERN WILL BE OVERNIGHT LOW TEMPERATURES IN THE MID TO UPPER 30S WHICH WILL PROMOTE SOME FROST DEVELOPMENT ACROSS THE COOLER SHELTERED INLAND LOCALES. THUS...A FROST ADVISORY MAY EVENTUALLY BE NEEDED. LESS LIKELY IS THAT A FEW SPOTS COULD DIP INTO THE LOWER 30S...WHICH COULD NECESSITATE A FREEZE WATCH AND/OR WARNING. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... OVERALL MODEL AGREEMENT IN THE LONG TERM PERIOD IS PRETTY GOOD. THE UPPER RIDGE WILL HANG ON ALONG THE EASTERN SEABOARD THROUGH MONDAY BEFORE BEING ERODED AWAY FROM THE WEST BY A DE-AMPLIFYING TROF MOVING ACROSS THE GREAT LAKES INTO TUESDAY. AT THE SURFACE...HIGH PRESSURE LOCATED TO THE NORTHEAST WILL CONTINUE TO EXTEND INTO THE REGION THROUGH MONDAY. THE MODELS HINT AT THE DEVELOPMENT OF A WEAK SURFACE TROF AND A MORE ONSHORE EASTERLY FLOW. THE MODEL PRECIP RESPONSE IS QUITE MUTED...AND THE MAIN AFFECT OF THE INCREASINGLY ONSHORE FLOW WILL BE MORE LOW LEVEL MOISTURE AND CLOUD COVER. ONCE THE RIDGE FINALLY BREAKS DOWN AND THE HIGH RETREATS FURTHER TO THE NORTHEAST...THE MODELS DEPICT A COLD FRONT APPROACHING THE AREA FROM THE WEST MONDAY NIGHT INTO TUESDAY. GIVEN THE WEAKENING NATURE OF THE FRONT AND THE UPPER TROF...I HAVE KEPT POPS IN THE LOW END CHANCE TO SLIGHT CHANCE RANGE AT THE END OF THE FORECAST PERIOD. TEMPS WILL GENERALLY RUN AT OR JUST ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... VFR. EXTENDED AVIATION OUTLOOK...MAINLY VFR. && .MARINE... NW FLOW TO CONTINUE THROUGH TONIGHT WITH A SLIGHT INCREASE LATE THIS EVENING AND OVERNIGHT AS A LOW-LEVEL JET SHIFTS THROUGH. ALL WATERS SHOULD STAY BELOW ADVISORY CRITERIA ALTHOUGH A FEW BRIEF GUSTS TO 25 KT ARE POSSIBLE OVER FAR OUTER PORTIONS OF THE OFFSHORE GA WATERS. THURSDAY THROUGH MONDAY...RATHER QUIET MARINE CONDITIONS EXPECTED THIS PERIOD...ESPECIALLY AFTER THURSDAY MORNING...WITH WINDS MAINLY 15 KT OR LESS AS HIGH PRESSURE SHIFTS FROM WEST TO EAST ACROSS THE AREA. A TROUGH OF LOW PRESSURE MAY DEVELOP OFF THE COAST EARLY NEXT WEEK AS THE HIGH MOVES OFFSHORE BUT THIS FEATURE WOULD GENERALLY AFFECT WIND DIRECTIONS MORE SO THAN SPEEDS. SEAS WILL REMAIN 2-3 FT OR LESS INTO SUNDAY BEFORE BUILDING EARLY NEXT WEEK GIVEN THE INCREASING EAST NORTHEAST SWELL. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FROST ADVISORY UNTIL 8 AM EST THIS MORNING FOR SCZ040-042>045. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...RJB LONG TERM...BSH AVIATION... MARINE...ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
313 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * MVFR VIS IN BR OVERNIGHT. * CHANCE FOR IFR VIS IN FG OVERNIGHT IF CLOUD COVER CAN CLEAR OUT EARLY ENOUGH BEFORE SUNRISE. * LOWER VFR CIGS OVC035-040...POSSIBLY SCATTERING OUT DURG THE EARLY MORNING HOURS. KREIN //DISCUSSION...UPDATED 06Z... MAIN CONCERN FOR THE REMAINDER OF THE NIGHT WILL FOCUS ON CIGS/VIS. LATEST SATELLITE IMAGERY SHOWS AN AREA OF ST OVER IL/WI...WITH THE EASTERN EDGE VERY CLOSE TO GYY AND THE WESTERN EDGE OVER ERN IOWA. THE TREND FOR THE CLOUD COVER SHOULD BE TO THIN OVERNIGHT AS A SFC RIDGE AXIS MOVES EWD ACROSS THE REGION. PATCHY AREAS OF 3-5SM BR HAVE DEVELOPED AS WINDS ARE CALM AND RESIDUAL MOISTURE FROM RECENT RAIN REMAINS IN PLACE. HOWEVER...THE THICK ST DECK HAS PREVENTED ANY SIGNIFICANT RADIATIONAL COOLING...KEEPING DEWPOINT DEPRESSIONS FROM DROPPING BELOW 2-3 DEGREES. THERE IS THE POTENTIAL FOR VISIBILITY TO QUICKLY DROP TO IFR LEVELS...OR LOWER...IF SKIES CAN CLEAR OUT EARLY ENOUGH BEFORE SUNRISE. IT REMAINS UNCERTAIN AT THIS POINT IF THIS WILL HAPPEN...WILL MAINTAIN MVFR VISIBILITY IN THE TAFS AND MONITOR CLOSELY FOR POSSIBLE UPDATES. CONDITIONS SHOULD BE RATHER QUIET AT THE TERMINALS THROUGH THE DAY TOMORROW WITH LIGHT WINDS PERSISTING THROUGH THE MORNING. WINDS SHOULD STRENGTHEN BY LATE MORNING/EARLY AFTERNOON AND BECOME MORE SLY-SWLY AS A TROUGH OF LOW PRESSURE MOVES EWD ACROSS THE PLAINS. EXPECT THAT WINDS SHOULD INCREASE TO ARND 10KT...WITH SOME OCNL HIGHER GUSTS THROUGH THE AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM CONFIDENCE IN CIG/VIS TRENDS OVERNIGHT. * LOW CONFIDENCE IN FOG WITH IFR OR LOWER VIS OVERNIGHT. * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS FROM LATE MORNING THROUGH THE END OF THE FORECAST PERIOD. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...SLIGHT CHANCE SHRA/TSRA FRIDAY NIGHT. SATURDAY...CHANCE OF SHRA/TSRA...MAINLY SATURDAY NIGHT. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE. TUESDAY...VFR. KJB && .MARINE... 315 AM CST A RIDGE OF HIGH PRESSURE OVER THE CENTRAL AND EASTERN GREAT LAKES WILL WILL KEEP RELATIVELY LIGHT WINDS OVER LAKE MICHIGAN THIS MORNING. AS THE HIGH SAGS SOUTHEASTWARD ACROSS THE OHIO VALLEY TODAY AND A WEAK TROUGH OF LOW PRESSURE MOVES INTO THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON...WINDS OVER THE LAKE WILL BECOME SOUTHWESTERLY AND STRENGTHEN. THE PRESSURE GRADIENT WILL BE STRONGEST OVER THE NORTHERN PORTIONS TO THE LAKE WITH WINDS INCREASING TO 15 TO 25 KT. WINDS OVER THE SOUTHERN PORTIONS OF THE LAKE WILL BE A BIT WEAKER...AROUND 10 TO 15 KT. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND DEEPEN AS IT TRACKS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL STRENGTHEN TO 30KT ACROSS THE LAKE...AND DURING THE PERIOD WHEN THE LOW IS DEEPENING OVER NRN WISCONSIN AND WESTERN LAKE SUPERIOR...THERE WILL BE A CHANCE FOR SOME 35KT GALE FORCE GUSTS SATURDAY NIGHT AND SUNDAY MORNING. AS THE LOW TRACKS NORTHEAST TO JAMES BAY SUNDAY NIGHT...IT WILL DRAG A STRONG COLD FRONT ACROSS LAKE MICHIGAN...TURNING WINDS WESTERLY TO NORTHWESTERLY. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
240 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * OCNL MVFR VIS IN BR OVERNIGHT. * CHANCE FOR IFR VIS IN FG OVERNIGHT IF CLOUD COVER CAN CLEAR OUT EARLY ENOUGH BEFORE SUNRISE. * LOWER VFR CIGS OVC035-040...POSSIBLY SCATTERING OUT DURG THE EARLY MORNING HOURS. KREIN //DISCUSSION...UPDATED 06Z... MAIN CONCERN FOR THE REMAINDER OF THE NIGHT WILL FOCUS ON CIGS/VIS. LATEST SATELLITE IMAGERY SHOWS AN AREA OF ST OVER IL/WI...WITH THE EASTERN EDGE VERY CLOSE TO GYY AND THE WESTERN EDGE OVER ERN IOWA. THE TREND FOR THE CLOUD COVER SHOULD BE TO THIN OVERNIGHT AS A SFC RIDGE AXIS MOVES EWD ACROSS THE REGION. PATCHY AREAS OF 3-5SM BR HAVE DEVELOPED AS WINDS ARE CALM AND RESIDUAL MOISTURE FROM RECENT RAIN REMAINS IN PLACE. HOWEVER...THE THICK ST DECK HAS PREVENTED ANY SIGNIFICANT RADIATIONAL COOLING...KEEPING DEWPOINT DEPRESSIONS FROM DROPPING BELOW 2-3 DEGREES. THERE IS THE POTENTIAL FOR VISIBILITY TO QUICKLY DROP TO IFR LEVELS...OR LOWER...IF SKIES CAN CLEAR OUT EARLY ENOUGH BEFORE SUNRISE. IT REMAINS UNCERTAIN AT THIS POINT IF THIS WILL HAPPEN...WILL MAINTAIN MVFR VISIBILITY IN THE TAFS AND MONITOR CLOSELY FOR POSSIBLE UPDATES. CONDITIONS SHOULD BE RATHER QUIET AT THE TERMINALS THROUGH THE DAY TOMORROW WITH LIGHT WINDS PERSISTING THROUGH THE MORNING. WINDS SHOULD STRENGTHEN BY LATE MORNING/EARLY AFTERNOON AND BECOME MORE SLY-SWLY AS A TROUGH OF LOW PRESSURE MOVES EWD ACROSS THE PLAINS. EXPECT THAT WINDS SHOULD INCREASE TO ARND 10KT...WITH SOME OCNL HIGHER GUSTS THROUGH THE AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW CONFIDENCE IN CIG/VIS TRENDS OVERNIGHT. * LOW CONFIDENCE IN FOG WITH IFR OR LOWER VIS OVERNIGHT. * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS FROM LATE MORNING THROUGH THE END OF THE FORECAST PERIOD. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... FRIDAY...SLIGHT CHANCE SHRA/TSRA FRIDAY NIGHT. SATURDAY...CHANCE OF SHRA/TSRA...MAINLY SATURDAY NIGHT. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...CHC RAIN CHANGING TO SNOW. MVFR/IFR POSSIBLE. TUESDAY...VFR. KJB && .MARINE... 354 PM CST A WEAK RIDGE OF HIGH PRESSURE WILL BRING A PERIOD OF FAIRLY LIGHT WINDS TO START TONIGHT...FOLLOWED BY LOW PRESSURE OVER THE NORTHERN HIGH PLAINS LIFTING NORTHEAST TO HUDSON BAY BY THURSDAY EVENING AND THE HIGH PRESSURE DRIFTING SOUTHEAST. DURING THIS TIME...WINDS WILL BECOME SOUTHWEST AND INCREASE. WINDS UP TO 30 KT ARE EXPECTED ON THE NORTH HALF OF THE LAKE...AND IN THE 15 TO 25 KT RANGE OVER THE OPEN WATERS OF THE SOUTH HALF. A WEAKER PRESSURE GRADIENT ON FRIDAY WILL RESULT IN LIGHTER SOUTHERLY WINDS. ATTENTION THEN TURNS TO A STRONG AREA OF LOW PRESSURE DEVELOPING OVER THE CENTRAL PLAINS ON FRIDAY AND TRACKING NORTHEAST TO LAKE SUPERIOR BY SATURDAY NIGHT AND TO JAMES BAY BY SUNDAY NIGHT. WINDS WILL INCREASE LATE FRIDAY NIGHT AND REALLY RAMP UP SATURDAY NIGHT THROUGH SUNDAY DUE TO A VERY TIGHT PRESSURE GRADIENT. HAVE AGAIN INDICATED OCCASIONAL GALES IN THE FORECAST...WITH THE MOST CONFIDENCE IN THEM OCCURRING AND POSSIBLY EVENTUALLY NEEDING A GALE WATCH OVER THE NORTH HALF. GALES APPEAR POSSIBLE ON THE SOUTH HALF ON SUNDAY AFTERNOON. THE LIMITING FACTOR FOR THIS EVENT WILL BE THAT THE AIR MASS MOVING OVER THE LAKE WILL BE WARMER THAN THE LAKE WATERS...CREATING STABLE CONDITIONS. HOWEVER...THE PRESSURE GRADIENT ALONE MAY BE TIGHT ENOUGH TO ALLOW FOR GALES AND FORECAST SOUNDINGS FOR THE NORTH BUOY SHOW WINDS CLOSE TO 40 KT JUST 100-200 FT OFF THE LAKE SURFACE. SMALL CRAFT CRITERIA WINDS ARE ALSO POSSIBLE IN THE NEAR SHORE WATERS FROM SATURDAY THROUGH SUNDAY. A STRONG COLD FRONT TRAILING FROM THE LOW PRESSURE AREA WILL PUSH ACROSS THE LAKE SUNDAY EVENING AND NIGHT...WITH STRONGER NORTHERLY OR NORTHWESTERLY WINDS BEHIND THE FRONT ON MONDAY AS MUCH COLDER AIR RETURNS TO THE REGION. RC && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1240 AM EST THU NOV 8 2012 .AVIATION... SATELLITE SHOWS CLEAR SKIES ACROSS INDIANA BUT SURFACE OBSERVATIONS SHOW FOG DEVELOPING ACROSS WESTERN AREAS...JUST WEST OF KSBN. LARGE AREA OF CLOUDS REMAINED TRAPPED UNDER INVERSION ACROSS IL. CIGS ARE BETWEEN 2 AND 4 KFT. FLOW WILL REMAIN LIGHT WITH RIDGE OVER AREA THROUGH DAYBREAK. ADDED SOME MENTION OF BR AT KSBN GIVEN SURROUNDING OBS. LOW LEVEL FLOW WILL BECOME SOUTHWEST THIS MORNING AND CONCERNED THAT CLOUDS OVER IL WILL BEGIN TO ADVECT EAST FOLLOWING RUC AND LOCAL WRF TRAJECTORIES. HAVE KEPT A SCT CLOUD LAYER BUT THIS COULD EASILY BECOME BKN TO OVC AND FLIRT WITH MVFR DURING THE MORNING IF THESE CLOUDS DO NOT MIX. THIS WILL CONTINUE TO BE MONITORED. OTHERWISE NOT EXPECTING ANY SIGNIFICANT WEATHER THIS PERIOD. && .UPDATE... PREVIOUS FORECAST IN GOOD SHAPE AND AN EVENING UPDATE IS CURRENTLY NOT ANTICIPATED. BACKING OF LOW LEVEL WINDS LATE EVENING/OVERNIGHT ASSOCIATED WITH APPROACHING LOW LEVEL RIDGE AXIS MAY TEND TO ADVECT STRATOCU DECK ACROSS NORTHEAST ILLINOIS EASTWARD...POSSIBLY CLIPPING PORTIONS OF FAR NORTHWESTERN PORTIONS OF FORECAST AREA. HOWEVER...LOW LEVEL FLOW TO REMAIN QUITE WEAK OVERNIGHT AND CONFIDENCE IN ANY EASTWARD EXPANSION OF NORTHEAST ILLINOIS STRATOCU IS LOW AT THIS TIME. THE UNDERCUTTING OF MOS GUIDANCE FOR MINS TONIGHT STILL APPEARS TO BE ON TRACK GIVEN GOOD RADIATIONAL COOLING CONDITIONS...AND RECENT MOS WARM BIASES. && .PREV DISCUSSION... /ISSUED 344 PM EST WED NOV 7 2012/ SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT DRY AIR/MAINLY SUNNY SKIES HAS WON OUT TODAY ACROSS MOST LOCATIONS THANKS TO LOW LVL RIDGE BUILDING BACK SW INTO THE LOWER LAKES. EXPECT LITTLE CHANGE INTO TONIGHT GIVEN VERY WEAK PRESSURE/THERMAL ADVECTION/FLOW WITH SOME THIN CIRRUS SPILLOVER INTO THE AREA ON EASTERN FRINGE OF CENTRAL CONUS UPPER RIDGE AXIS. OPTED TO ADD PATCHY FOG ACROSS FAR SWERN ZONES FOR LATER TONIGHT GIVEN CLOSE PROXIMITY TO LINGERING LOW LVL MOISTURE AXIS ACROSS WI/IL/FAR WESTERN IN. CLEAR SKIES AND CALM WINDS UNDER BUILDING SFC HIGH WILL SUPPORT OPTIMAL LONGWAVE LOSS TONIGHT. THIS WILL ALLOW TEMPS TO PLUMMET MAINLY INTO THE MID/UPPER 20S. AIRMASS DRY AS MENTIONED BUT WITH TEMPS FCST TO DROP BLO XOVER VALUES MAY SEE SOME PATCHY FOG DEVELOP ACROSS CENTRAL/EASTERN ZONES...MAINLY NEAR AREA LAKES. COVERAGE/PROBABILITY OF FOG REMAINS TOO LOW TO INCLUDE IN THE GRIDS OUTSIDE OF OUR FAR SW AS MENTIONED ABOVE. WARM AIR ADVECTION THEN ENSUES THURSDAY AFTERNOON INTO THURSDAY NIGHT AS UPPER RIDGE BUILDS OVER THE AREA. WITH SFC RIDGE NEAR TOMORROW NOT EXPECTING A VERY DEEP MIXED LAYER WHICH SHOULD TEMPER WARMUP A BIT AT THE SFC...ESPECIALLY IF DECENT DIURNAL CU FIELD MATERIALIZES AS HEIGHT/MASS ADJUSTMENTS WITH BUILDING RIDGE AND MID LVL SHORTWAVE TRACKING EAST INTO MANITOBA/ONTARIO FORCES LEFTOVER BOUNDARY LAYER MOISTURE UNDER SUBSIDENCE INVERSION EAST INTO AT LEAST OUR IN/MI ZONES. REGARDLESS...THURSDAY OVERALL STILL APPEARS TO BE ANOTHER MOSTLY SUNNY DAY WITH HIGHS A LITTLE WARMER THAN TODAY INTO THE LOWER 50S. LONG TERM.../FRI-WED/ DEEPENING UPR TROF OFF THE PAC NW COAST THIS AFTN EXPECTED TO BE OVER THE WRN U.S. FRIDAY WITH BUILDING DOWNSTREAM RIDGE OVER THE MS VALLEY/GRTLKS. RECENT MODEL RUNS HAVE BEEN FAIRLY CONSISTENT SUGGESTING THESE FEATURES WILL PROGRESS E-NE THROUGH THE LONG TERM PERIOD. MAIN SFC LOW ASSOCIATED WITH THE UPR TROF IS EXPECTED TO DEEPEN OVER NERN CO FRI AND LIFT NE INTO MN SAT. WARM FRONT ASSOCIATED WITH THIS LOW SHOULD EXTEND EASTWARD INTO THE NRN PORTION OF OUR CWA BY FRI EVE WITH LLJ OVER THE PLAINS INTO THE MID MS/LWR OH VALLEY. THIS MAY PROVIDE SUFFICIENT MOISTURE TRANSPORT/CONVERGENCE AND WK ELEVATED INSTABILITY FOR A FEW SHOWERS ACROSS NRN PORTION OF THE CWA FRI NGT/SAT. OTRWS ABOVE NORMAL TEMPS EXPECTED FRI-SUN AS DEEP SOUTHERLY FLOW OVERSPREADS THE AREA AND STRENGTHENS. HEIGHT FALLS AND SFC MOISTURE CONVERGENCE ASSOCIATED WITH THE APCHG UPR TROF/SFC CDFNT SHOULD SPREAD SHOWERS INTO THE AREA BY SUNDAY NIGHT. BIG QUESTION REMAINS IF/WHEN/WHERE SFC WAVE WILL DEVELOP ALONG CDFNT AS IT MOVES THROUGH THE ERN U.S.. LATEST MEDIUM RANGE MODELS HAVE VARIOUS SOLUTIONS IN THIS REGARD. PREFERENCE WITH MOST CONSISTENT ECMWF INDICATING WK WAVE MOVING NNE ALONG THE CDFNT AS IT MOVES THROUGH THE REGION. THIS SHOULD CAUSE THE FRONT TO SLOW DOWN ENOUGH TO KEEP SOME PRECIP IN THE AREA THROUGH AT LEAST A PORTION OF MONDAY NIGHT. CAA MAY CAUSE PRECIP TO CHANGE OVER TO SNOW BRIEFLY BEFORE ENDING... ESPECIALLY IF A STRONGER WAVE DEVELOPS ALONG THE FRONT AS SUGGESTED BY 12Z GFS/GEM. HAVE ADDED CHC OF SNOW TO FCST FOR LATE MONDAY NIGHT BUT EXPECTING LTL OR NO ACCUM. STRONG CAA BEHIND THE FRONT MAY ALSO RESULT IN FALLING TEMPS AT LEAST ACROSS WRN PORTION OF THE CWA MONDAY WITH MUCH COOLER HIGHS IN THE L-M40S ACROSS THE ENTIRE AREA BY TUE. THIS COLD SNAP SHOULD BE SHORT LIVED AS UPR TROF LIFTS RAPIDLY NE AND WKNS... AND FLOW BACKS OVER THE GRTLKS AS ANOTHER TROF DIGS INTO WRN US. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...STEINWEDEL LONG TERM...JT AVIATION...LASHLEY UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1137 PM CST WED NOV 7 2012 .AVIATION... HIGH PRESSURE CENTERED OVER IL WILL DRIFT SOUTHEAST INTO THE LOWER OHIO RIVER VALLEY BY THURSDAY MORNING. A LARGE AREA OF CLOUDS WITH CIGS FROM 25HND TO 35HND FT EXTENDS WEST INTO EASTERN IA LATE THIS EVENING. THE CLOUDS WILL CONTINUE TO CLEAR FROM WEST TO EAST OVERNIGHT AND SHOULD BE EAST OF ALL TAF SITES BETWEEN 09Z AND 11Z. ONCE THE CLOUDS CLEAR SOME FOG IS EXPECTED TO DEVELOP BUT HIGH CLOUDS/CIRRUS STREAMING IN FROM THE NORTHERN PLAINS AND WINDS PICKING UP OUT OF THE SOUTH OR SOUTHEAST SHOULD HELP KEEP VISIBILITIES IN THE 3-5SM RANGE. FOR THURSDAY VFR CONDITIONS ARE EXPECTED WITH SOUTH WINDS INCREASING TO 10 TO 20KTS BY MID MORNING AND CONTINUING THROUGH THE AFTERNOON THEN DROPPING TO LESS THAN 10KTS DURING THE EVENING. DLF PREV DISCUSSION... /ISSUED 259 PM CST WED NOV 7 2012/ SYNOPSIS... LATEST SFC ANALYSIS WAS INDICATING RIDGE AXIS CONTINUING TO SLIDE ACRS THE EASTERN PLAINS INTO THE WESTERN GRT LKS. CENTRAL TO NORTHERN PLAINS RIFE WITH PRESSURE FALLS AND LLVL RETURN FLOW... TEMPS IN THE 50S AND 60S. 12Z UPPER AIR ANALYSIS AND MID/HIGH LEVEL MOISTURE FLOW PATTERNS ON CURRENT WATER VAPOR LOOP SHOW PREVIOUSLY PRONOUNCED UPPER RIDGE ACRS THE ROCKIES GETTING PRESSED EASTWARD ACRS THE NORTHERN PLAINS BY SURGE OF PACIFIC NW UPPER JET ENERGY. OTHER UPPER JET MAX OVER THE ARE THIS MORNING STARTING TO DEPART OFF TO THE SOUTHEAST INTO EAST COAST L/W TROF BASE. SHORT TERM...TONIGHT AND THURSDAY... TONIGHT...MAIN CHALLENGE TONIGHT CONTINUES TO BE WHAT WILL HAPPEN TO ONGOING CLOUD DECK ALIGNED ACRS MUCH OF THE UPPER TO MID MS RVR VALLEY REGIONS. DEPARTING UPPER JET TO THE SE AND ARRIVAL OF UPSTREAM RIDGE GETTING PRESSED ACRS THE AREA WILL CONTINUE TO ENHANCE ONGOING SUBSIDENCE REGIME WHICH NORMALLY WOULD MEAN A CLOUD DECAY/CLEAR OUT. BUT FCST SOUNDINGS AND UPPER AIR SOUNDINGS SUGGEST TRAPPING INVERSION ALOFT TO GET ENHANCED BY THE SAME PROCESSES THIS EVENING AND INTO THE OVERNIGHT...WHICH COULD TRAP THE CLOUD COVER AND LIMIT CLEAR OUT TRENDS INTO EARLY THU MORNING. LATEST RAP RUNS IN HANDLING MOISTURE IN THE H95-H85 MB LAYER ALSO POINT TO THE LOW CLOUDS GETTING TRAPPED ALONG AND EAST OF THE MS RVR THROUGH AT LEAST MIDNIGHT BEFORE SOME CLEARING PUSH INCREASE FROM THE WEST AFTER 09Z TONIGHT. WEST OF THE MS RVR...EXPECT PREVIOUS CLEARING HOLES THAT DIURNALLY FILLED WITH CUMULUS TO CLEAR OUT AGAIN AFTER SUNSET...MAKING FOR A PATCHY CLEARING PATTERN ACRS THE WESTERN HALF OF THE CWA AS THE EVENING PROGRESSES. WILL PLAY THE CLOUDS A BIT MORE PESSIMISTIC IN THE FCST AND HANG THEM ON ESPECIALLY ACRS THE EASTERN HALF OF THE CWA WELL PAST MIDNIGHT...WITH SOME CLEARING TRENDS TOWARD SUNRISE THU MORNING. RIDGE-RIDING CI WILL ALSO SPILL DOWN ACRS THE AREA FROM THE NORTHWEST. EVEN WITH DELAYED CLEARING TRENDS IN MIND...ONGOING LOWS GENERALLY STILL LOOK ON TARGET EXCEPT MAYBE A MINOR ADJUSTMENT UPWARD ACRS THE FAR EASTERN CWA. WITH LIGHT WINDS AND POSSIBLE CLEARING HOLES UNDER RIDGE AXIS...WILL KEEP THE PATCHY FOG MENTION INTRODUCED BY PREVIOUS SHIFT ACRS GENERALLY THE EASTERN HALF OF THE DVN CWA. WITH LACK OF CLEARING THIS AFTERNOON ACRS THE WESTERN HALF OF THE CWA AND THUS LIMITED DRYING...PATCHY FOG WORDING MAYBE WARRANTED FURTHER TO THE WEST. THURSDAY...SOME OF THE RETURN FLOW GRADIENT AND SUNSHINE GOING ON NOW ACRS THE EAST-CENTRAL PLAINS WILL MAKE ITS WAY ACRS THE LOCAL AREA. INCREASING SOUTHERLY WINDS AND LLVL WARM AIR ADVECTION SHOULD TRANSLATE LOCALLY TO WHAT IS CURRENTLY GOING ON ACRS EASTERN NEB AND FAR WESTERN IA...WIDESPREAD MID TO UPPER 50S WITH A CHANCE AT A 60 DEGREE READING BY LATE THU AFTERNOON. ..12.. LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY... NEAR RECORD WARMTH FRIDAY AND SATURDAY...THEN SIGNIFICANT RAINS WITH A STRONG COLD FRONTAL PASSAGE SUNDAY THE MAIN FORECAST ISSUES. OVERVIEW...LIMITED UPSTREAM SENSIBLE WEATHER INITIALIZATION ISSUES WITH D_PROG_DT AND MOISTURE BIASES SUPPORTING WITH COLD FRONT USING GFS AS THE PRIMARY TOOL. THIS SUPPORTS WIDESPREAD SEASONABLE HEAVY RAINFALL TOTALS OF .5+ OF AN INCH...UP TO LOCALLY 2.0 INCHES. THURSDAY NIGHT THROUGH FRIDAY...FAIR SKIES WITH INCREASING SOUTH WINDS THAT WILL BECOME BREEZY BY FRIDAY PM. NEARLY STEADY TO POSSIBLY SLOWLY RISING MINS IN THE 30S THURSDAY AM. THEN HIGHS IN THE UPPER 50S NE TO LOWER 60S SW WITH POSSIBLY HIGHER VALUES IF ENOUGH SUNSHINE AND BL MIXING OCCURS. FRIDAY NIGHT...VERY MILD WITH MINS WITHIN 5 DEGREES OF RECORD WARM MINS RANGING FROM UPPER 40S NE TO THE LOWER TO MIDDLE 50S SW SECTIONS. LOTS OF HIGH CLOUDS SHOULD ARRIVE INTO THE AREA FRIDAY NIGHT. SATURDAY AND SATURDAY NIGHT...STRONG WAA TO KEEP REGION WELL ABOVE NORMAL WITH TEMPERATURES WITHIN 5 DEGREES OF RECORDS. KEPT VERY LOW POPS WITH LIGHT -SHRA POSSIBLE WITH HIGH PW/S AND WEAK UPPER LEVEL DISTURBANCES INTERACTING WITH LOW LEVEL JET. LOCAL TOOLS SUPPORT LOWER 70S POSSIBLE WITH ENOUGH SUNSHINE FOR HIGHS AND MINS ONCE AGAIN IN THE LOWER/MIDDLE 50S. SUNDAY AND SUNDAY NIGHT...STRONG COLD FRONT TO PASS WITH TEMPERATURES CRASHING 25-30+ PLUS DEGREES WITHIN 6 HOURS OF THE FRONT PASSING. SIGNIFICANT BANDS OF MODERATE TO LOCALLY HEAVY RAIN/RAINSHOWERS AND SOME EMBEDDED BRIEF THUNDER ALONG AND JUST BEHIND THE FRONT. EXPECT A LARGE GRADIENT FOR MAX TEMPERATURES. GONE WITH NEAR 50F FAR NW TO THE MIDDLE 60S FAR SW SECTIONS. LIKELY THIS GRADIENT WILL BE GREATER ONCE TIMING ISSUE BETTER RESOLVED IN THE NEXT COUPLE OF DAYS. PW VALUES NEAR 1.5 INCHES AHEAD OF FRONT PER LOCAL TECHNIQUES CONFIRM AT LEAST .5 INCHES OF RAINFALL WITH 1.5+ INCHES WITH TRAINING AND EVEN HIGHER POSSIBLE WITH ANY WAVE ON THE FRONT. MONDAY THROUGH WEDNESDAY...FAIR SKIES AND SEASONABLY COLD WITH BELOW NORMAL TEMPERATURES. HIGHS MOSTLY IN THE MID 30S TO LOWER 40S AND MINS IN THE 20S...POSSIBLY UPPER TEENS IN FAVORED LOW LYING LOCATIONS. NICHOLS && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
323 AM CST THU NOV 8 2012 .DISCUSSION... TODAY-FRI: MAIN FOCUS IS ON MOISTURE RETURN AHEAD OF APPROACHING FRONT. GFS STILL APPEARS TO BE RUNNING MOIST...AND ALTHOUGH NAM EVOLUTION LOOKS GOOD...ITS ALREADY TOO FAST GIVEN OBSERVED SURFACE DEW POINTS ACROSS TX. HAVE TRENDED CLOSER TO RUC THIS MORNING AND THEN NAM/EC BLEND INTO FRI. GUSTY SOUTH WINDS ARE EXPECTED AS SURFACE PRESSURE GRADIENT INCREASES. COMBO OF POTENTIAL LOW CLOUDS AND INCREASING CIRRUS WILL MAKE BOTH MINIMUM/MAXIMUM TEMPERATURES TRICKY THIS PERIOD. EXPECT WINDS TO KEEP TEMPERATURES UP TONIGHT. BETTER CHANCE OF CLOUDS ON FRI MAY LIMIT WARMUP EAST OF I-35...WITH BIG WARMUP POSSIBLE ROUGHLY WEST OF HIGHWAY 14 WITH LOWER DEW POINTS AND MORE WEST/DOWNSLOPE WIND COMPONENT. SAT-SUN: OUTSIDE CHANCE THAT PRECIPITATION COULD BREAK OUT IN THETA-E ADVECTION ACROSS NORTHWEST SECTIONS OF FORECAST AREA SAT AFTERNOON...BUT CHANCES SHOULD RAMP UP SAT NIGHT-SUN AS FRONT MOVES THROUGH. NOW APPEARS THAT PRECIPITATION WOULD LIKELY END BEFORE FREEZING TEMPERATURES ARRIVE IN CENTRAL KS AND HAVE DROPPED MENTION OF SNOW AROUND DAYBREAK SUN FOR NOW. BY SUN MOST OF PRECIPITATION WILL BE EAST OF I-35...BUT TIMING IS A BIT QUESTIONABLE WITH FAIR AMOUNT DISCREPANCIES BETWEEN MODELS. PRECIPITATION MIGHT LINGER IN FAR SOUTHEAST SECTIONS INTO SUN NIGHT...BUT SUSPECT WOULD LIKELY BE LIMITED IN TIME AND SPACE. MUCH COLDER AIR WILL BE MOVING INTO THE AREA BEHIND THE FRONT. MON-WED: DRY CONDITION LIKELY THIS PERIOD. WITH BOTH GFS/ECMWF SHOWING UPPER FLOW BECOMING INCREASINGLY ZONAL THROUGH THIS PERIOD...EXPECT FAIRLY RAPID RECOVERY IN TEMPERATURES. HAVE NUDGED UP INITIALIZATION TEMPERATURES...ESPECIALLY ON WED FOR THIS. POTENTIAL IS EVEN WARMER. HOWEVER BOTH GFS/ECMWF SUGGEST THERE COULD BE FAIR AMOUNT OF CIRRUS IN THE AREA WITH THE LEFT FRONT QUADRANT OF APPROACHING 300MB SPEED MAXIMUM AND RELATIVELY LOW SUN ANGLE. -HOWERTON && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU A RIDGE OF HIGH PRESSURE ALOFT WILL RESULT IN TRANQUIL WEATHER ACROSS THE CENTRAL AND SOUTHERN PLAINS WHILE A TROUGH OF LOW PRESSURE AT THE SURFACE REMAINS ANCHORED OVER THE SOUTHERN HIGH PLAINS. THIS WILL RESULT IN INCREASING SOUTHERLY WINDS THROUGH THE DAY ON THURSDAY WITH GUSTS TO AROUND 30 KNOTS ANTICIPATED. MWM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 73 56 77 62 / 0 0 0 10 HUTCHINSON 70 55 78 59 / 0 0 0 10 NEWTON 69 56 76 59 / 0 0 0 10 ELDORADO 72 59 75 61 / 0 0 10 10 WINFIELD-KWLD 73 61 76 63 / 0 0 0 10 RUSSELL 65 45 81 57 / 0 0 0 10 GREAT BEND 69 45 82 58 / 0 0 0 10 SALINA 70 52 80 60 / 0 0 0 10 MCPHERSON 70 54 78 59 / 0 0 0 10 COFFEYVILLE 73 58 76 64 / 0 0 10 10 CHANUTE 69 56 75 60 / 0 0 10 10 IOLA 68 55 75 61 / 0 0 10 10 PARSONS-KPPF 70 60 76 62 / 0 0 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
414 AM EST THU NOV 8 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROVIDE DRY CONDITIONS AND A SLOW WARM UP INTO THE WEEKEND AND MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DYNAMICS IN ASSOCIATION WITH THE COASTAL SYSTEM SEEM TO BE RELEGATED TO AREAS TO OUR EAST...HOWEVER CIRRUS BLOW OFF/OUTFLOW FROM THE SYSTEM IS EMANATING INTO THE FORECAST AREA SEMI- CONTINUOUSLY STILL EARLY THIS MORNING. WHILE THE DYNAMICS ARE NOT PRESENT...AND THE CLOUD TOP TEMPERATURES ARE CONTINUOUSLY WARMING OVER THE AREA...THE TREND LOOKS TO BE TOWARD SLOW DISSIPATION OF CLOUD COVER OVER THE AREA. THE ONLY CAVEAT TO THIS MAY BE ALONG THE NORTHERN TIER OF COUNTIES...WHERE A BRIEF OVERLAP OF LOWER INVERSION HEIGHTS AND WIND THAT SLOWLY BACKS TOWARD NORTHERLY BY MORNING MAY BRING A BRIEF PERIOD OF STRATOCUMULUS UP NORTH OF I-80. OTHERWISE...THE TREND LOOKS TO BE TOWARD SLOW CLEARING ACROSS THE AREA THROUGH THE MORNING AS RIDGING AND SUBSIDENCE TAKE A MORE DOMINANT HOLD. EVEN WITH RIDGING STARTING TO BUILD INTO THE CENTRAL GREAT LAKES...OUR AREA REMAINS OVER LARGE SCALE NORTHWESTERLY FLOW. AS SUCH...LAYER TEMPERATURES FAIL TO IMPROVE MUCH AT ALL TODAY AND 850 MB TEMPERATURES ONLY RUN UP TOWARD 0 TO +1C BY AFTERNOON. THIS SORT OF IMPROVEMENT WOULD NOT REALLY BE ALL THAT EXCITING EXCEPT FOR THE FACT THAT ABUNDANT SUNSHINE IS QUITE A BIT MORE LIKELY TODAY THAN YESTERDAY. WITH INSOLATION AND SOME INCREASED LOW LEVEL TURBULENT MIXING...TEMPERATURES SHOULD START THEIR SLOW CREEP UPWARD IN TERMS OF HIGH TEMPERATURES BY AFTERNOON. FRIES && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... THE MID-LEVEL RIDGE AXIS CONTINUOUSLY BUILDS TOWARD THE AREA DURING THIS PORTION OF THE FORECAST...WITH THE MEAN AXIS POSITION AMONGST A MULTI-MODEL ENSEMBLE LOOK AT THE SPAGHETTI PLOTS INDICATING IT SHOULD CROSS THE AREA ROUGHLY ON SATURDAY. UNTIL THE RIDGE AXIS MOVES EAST OF THE AREA...INCREASED WARMING WILL BE PAINSTAKINGLY SLOW. THAT MEANS...AFTER SATURDAY...OUR TEMPERATURES MAY WELL BE OFF TO THE RACES. WITH THE RIDGE AXIS TO OUR EAST...LARGE SCALE FLOW FINALLY TURNS TOWARD THE SOUTHWEST ON ALL MODELS. AS THIS OCCURS...DEEP LAYER WARM ADVECTION GETS STARTED OVER THE AREA...ENOUGH THAT A WARM FRONTAL FEATURE LOOKS SET TO RIDE THROUGH THE LOWER GREAT LAKES SATURDAY OR SATURDAY NIGHT. GIVEN THE ORIENTATION OF THE CWA RELATIVE TO THE BEST AXIS OF 850-700 MB WARM ADVECTION...IT STILL SEEMS LIKE PRECIPITATION WILL BY-AND-LARGE OUTSIDE THE CWA...HOWEVER IT WILL NEED TO BE MONITORED. WHILE WARM ADVECTION SEEMS INCREASINGLY LIKELY TO RESULT IN WARM FRONTAL STRATIFORM RAINFALL JUST NORTH OF OUR CWA...THE INCREASING SOUTHWESTERLY FLOW IN ALL LOWERS WILL USHER WARMER AIR IN BY THE WEEKEND. TEMPERATURES AT 850 MB RUN UP TOWARD THE +12 TO +14C RANGE BY SUNDAY AND WITH INCREASED MIXING...HIGH TEMPERATURES MAY WELL SURGE INTO THE 65-70F REGION OVER MUCH OF THE AREA. THIS WOULD BE COLOSSALLY ABOVE NORMAL. FRIES && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE MODEL CONSENSUS REMAINS QUITE STRONG ALL THE WAY INTO THE EXTENDED. THE MID-LEVEL RIDGE THAT WILL HAVE CROSSED OUR CWA THIS WEEKEND WILL HAVE PARKED ITSELF JUST OFF THE COAST BY SUNDAY NIGHT PER ALL GUIDANCE. ADDITIONALLY...SEVERAL PIECES OF GUIDANCE SUGGEST THE MID-LEVEL CENTER SHOULD CLOSE OFF A SPRAWLING ANTI- CYCLONE OFF THE VIRGINIA COAST. . A FEW INTERESTING TIDE BITS SEEM TO FLOW OUT OF THE FORECAST. BOTH THE RIDGE/ANTI-CYCLONE JUST OFF SHORE HAVING CLOSED OFF WILL UNDOUBTEDLY AND THE NEXT INCOMING SYSTEM LOOK SET TO INTENSIFY...DEEPEN...AND CLOSE OFF. AS SUCH...THE ENTIRE LARGE SCALE PATTERN PROGRESSION LOOKS TO SLOW DOWN JUST A TAD. AS A RESULT...LIFT AHEAD OF THE NEXT SYSTEM SHOULD HOLD OFF UNTIL MONDAY EVENING TO REACH THE FORECAST AREA. A SLOWER PROGRESSION OF THE SYSTEM LOOKS TO KEEP THE FORECAST AREA SQUARELY IN THE WARMER AIR THROUGH THE DAY ON MONDAY...SO TEMPERATURES THERE WERE ADJUSTED UPWARD. ADDITIONALLY...THE SLOWER PROGRESSION LOOKS LIKELY TO GIVE THE FRONTAL RAIN BAND MORE RESIDENCE TIME OVER THE CWA. AS A RESULT...POPS WERE INCREASED IN THAT AREA AS WELL. A COMBINATION OF STRONG LOW LEVEL POSITIVE THERMAL ADVECTION...STRONG ALBEIT SEASONALLY ADJUSTED INSOLATION...AS WELL AS INCREASING MIXING DUE TO STRONGER LOW LEVEL FLOW ON THE UPSTREAM SIDE OF THE MID-LEVEL TROUGH WILL UNDOUBTEDLY ALLOW OUR TEMPERATURES TO RUN UP A BY ON FRIDAY. THE ONLY REAL QUESTION MARK REVOLVES AROUND TEMPERATURES ON TUESDAY. AFTER EXAMINING THE SOLUTIONS AND FAVORING A SLOWER ONE...THIS SHOULD HELP EVERYWHERE SEE RAIN BY THE MIDDLE OF NEXT WEEK AS WELL AS LEAVE US IN THE WARM AIR FOR ONE EXTRA AFTERNOON. TO ACCOUNT FOR THESE TWO IDEAS...TEMPERATURES WERE CUT AND SKIES WERE CLEARED OUT AGAIN BY AFTERNOON. FRIES && .AVIATION /09Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL PREVAIL FOR THE MAJORITY TODAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTHWEST. THE ONE EXCEPTION TO VFR CONDITIONS WILL BE THE POTENTIAL FOR MVFR CEILINGS TO DEVELOP IN A NORTHERLY FLOW OFF OF LAKE ERIE AND MOVE SOUTHWARD INTO KFKL/KDUJ NEAR DAWN THIS MORNING. THIS IS A MEDIUM CONFIDENCE FORECAST WITH SUPPORT FROM THE RAP MODEL. ANY CEILINGS THAT DEVELOP ACROSS THE NORTH WILL DIMINISH ALONG WITH CIRRUS BY LATE MORNING...LEAVING CLEAR SKIES ACROSS THE TAF SITES. WINDS TODAY WILL BE NORTHWESTERLY AT 5 TO 10KTS. .OUTLOOK.../FRIDAY THROUGH MONDAY/... THERE IS LOW CONFIDENCE IN BRIEF CEILING RESTRICTIONS AT KFKL/KDUJ ON FRIDAY MORNING. OTHERWISE...VFR WILL PREVAIL THOUGH MONDAY WITH HIGH PRESSURE CONTINUING TO BUILD IN. RESTRICTIONS ASSOCIATED WITH AN INCOMING COLD FRONT WILL LIKELY NOT ARRIVE UNTIL MONDAY NIGHT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1258 AM EST THU NOV 8 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROVIDE DRY CONDITIONS AND A SLOW WARM UP INTO THE WEEKEND AND MONDAY. && .NEAR TERM /THROUGH TODAY/... DYNAMICS IN ASSOCIATION WITH THE COASTAL SYSTEM SEEM TO BE RELEGATED TO AREAS TO OUR EAST...HOWEVER CIRRUS BLOW OFF/OUTFLOW FROM THE SYSTEM IS EMANATING INTO THE FORECAST AREA SEMI- CONTINUOUSLY TONIGHT. WHILE THE DYNAMICS ARE NOT PRESENT...AND THE CLOUD TOP TEMPERATURES ARE CONTINUOUSLY WARMING OVER THE AREA...THE TREND LOOKS TO BE TOWARD SLOW DISSIPATION OF CLOUD COVER OVER THE AREA. THE ONLY CAVEAT TO THIS MAY BE ALONG THE NORTHERN TIER OF COUNTIES...WHERE A BRIEF OVERLAP OF LOWER INVERSION HEIGHTS AND WIND THAT SLOWLY BACKS TOWARD NORTHERLY BY MORNING MAY BRING A BRIEF PERIOD OF STRATOCUMULUS UP NORTH OF I-80. OTHERWISE...THE TREND LOOKS TO BE TOWARD SLOW CLEARING ACROSS THE AREA THROUGH THE MORNING. WITH CLOUDS TONIGHT...TEMPERATURES WILL HAVE DIFFICULTY FALLING ALL THE WAY TO THEIR DEWPOINTS...WHICH IS A GOOD THING BECAUSE THOSE HAVE FALLEN INTO THE TEENS AND LOWER 20S AREA WIDE. REGARDLESS OF THIS...ANOTHER VERY COLD NIGHT IS IN STORE BEFORE SUN WILL RETURN TO THE AREA AS LAYER RH VALUES FALL OFF A CLIFF ON THURSDAY AND THE STRATOCUMULUS BURNS OFF NORTH OF I-80 AS INVERSION-TOP SATURATION IS QUICKLY ERODED BY DAYTIME TURBULENT MIXING IN THE BOUNDARY LAYER. AS SUCH...THE BEGINNINGS OF THE SLOW WARMING TREND LOOK TO FINALLY TAKE HOLD BY THE AFTERNOON. FRIES && .SHORT TERM /TONIGHT THROUGH SATURDAY/... RECENT SREF MODEL OUTPUT SHOWS SURFACE HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. THIS PERIOD. EXPECTED SUBSIDENCE WILL PROMOTE MAINLY CLEAR SKIES AND A GRADUAL WARM UP. SOUTHWEST WINDS WILL INCREASE ACROSS THE UPPER OHIO VALLEY SATURDAY WITH MOST SREF MEMBERS SHOWING WARM FRONTAL CLOUD AND SHOWER DEVELOPMENT NORTH OF THE GREAT LAKES. CONCUR WITH RECENT NAM AND GFS MOS THAT TEMPERATURES WILL REACH SEASONABLE LEVELS FRIDAY...WITH SATURDAY AFTERNOON HIGHS NEARLY 10 DEGREES WARMER THAN NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE RIDGE WILL EXTEND ACROSS MUCH OF THE EASTERN UNITED STATES ON SUNDAY...MOVING OFFSHORE ON MONDAY. ENSEMBLE RUNS ARE SHOWING COLD FRONT ARRIVING SLOWER FOR MONDAY...WITH DETERMINISTIC RUNS DELAYING THE ARRIVAL OF THE FRONT EVEN MORE. HAVE SLOWED DOWN TIMING BY ABOUT 6 HOURS...WITH PLENTY OF TIME TO MODIFY THE TIMING. ALSO BROUGHT UP POPS SLIGHTLY WITH THE FRONT AS WELL...WITH PASSAGE SOMEWHERE BETWEEN MONDAY AFTERNOON AND MONDAY EVENING. ONCE PRECIPITATION CLEARS ON TUESDAY...WIND DIRECTION APPEARS TO BE MARGINALLY FAVORABLE FOR LAKE EFFECT TUESDAY NIGHT INTO WEDNESDAY. FRONTAL PRECIP IS EXPECTED TO BE ALL RAIN...WITH BOTH RAIN AND SNOW POSSIBLE WITH LAKE EFFECT. NORMAL TEMPERATURES ARE MID 50S/MID 30S...AND SUNDAY AND MONDAY ARE EXPECTED TO BE ABOUT 10 DEGREES ABOVE NORMAL. BEHIND THE FRONT...TEMPERATURES WILL CRASH TO 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /05Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL PREVAIL FOR THE MAJORITY TODAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTHWEST. THE ONE EXCEPTION TO VFR CONDITIONS WILL BE THE POTENTIAL FOR MVFR CEILINGS TO DEVELOP IN A NORTHERLY FLOW OFF OF LAKE ERIE AND MOVE SOUTHWARD INTO KFKL/KDUJ NEAR DAWN THIS MORNING. THIS IS A MEDIUM CONFIDENCE FORECAST WITH SUPPORT FROM THE RAP MODEL. ANY CEILINGS THAT DEVELOP ACROSS THE NORTH WILL DIMINISH ALONG WITH CIRRUS BY LATE MORNING...LEAVING CLEAR SKIES ACROSS THE TAF SITES. WINDS TODAY WILL BE NORTHWESTERLY AT 5 TO 10KTS. .OUTLOOK.../FRIDAY THROUGH MONDAY/... THERE IS LOW CONFIDENCE IN BRIEF CEILING RESTRICTIONS AT KFKL/KDUJ ON FRIDAY MORNING. OTHERWISE...VFR WILL PREVAIL THOUGH MONDAY WITH HIGH PRESSURE CONTINUING TO BUILD IN. RESTRICTIONS ASSOCIATED WITH AN INCOMING COLD FRONT WILL LIKELY NOT ARRIVE UNTIL MONDAY NIGHT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
346 AM CST THU NOV 8 2012 .SHORT TERM...TODAY THROUGH FRIDAY AFTERNOON... FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR MIXED PRECIPITATION THIS MORNING...MUCH COOLER TEMPERATURES TODAY AND FRIDAY...AND WINTER WEATHER HEADLINES TONIGHT INTO FRIDAY. 00Z MODELS ARE NOT AGREEING MUCH WITH EACH OTHER. OPTED TO LEAN MORE ON CONSISTENCY WITH THIS FORECAST ISSUANCE. CURRENTLY...S/WV TRACKING EAST ACROSS SOUTHERN SASKATCHEWAN INTO SOUTHERN MANITOBA THIS MORNING WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTHWARD ACROSS CENTRAL NORTH DAKOTA TO ANOTHER LOW OVER WESTERN/CENTRAL SOUTH DAKOTA. REGIONAL RADAR CONTINUES TO SHOW A LINE OF LIGHT RAIN ALONG A FRONTAL BOUNDARY EXTENDING FROM TROTTERS/BEACH...EAST-NORTHEAST THROUGH GARRISON AND INTO THE DEVILS LAKE AREA. WITH SOME EMBEDDED ELEVATED RETURNS AND WITH SFC OBS REPORTING LIGHT RAIN THE PAST SEVERAL HOURS...WILL MAINTAIN HIGH CHANCE POPS FOR THIS ACTIVITY THROUGH 12Z. FRONTAL BOUNDARY WILL CONTINUE TO PUSH SOUTH AS THE S/WV CONTINUES EAST. LINE OF PRECIPITATION WILL SHIFT SOUTH AS WELL AND EVENTUALLY DISSIPATES DUE TO LACK OF FORCING. CAA BEHIND THE BOUNDARY IS COOLING THE THERMAL PROFILE ENOUGH FOR POSSIBLE MIXED PRECIPITATION THIS MORNING MAINLY NORTH WHERE SURFACE TEMPS HAVE COOLED TO THE LOW/MID 30S. IN ADDITION TO THE CAA...LARGE AREA OF LOW STRATUS CONTINUES TO SURGE SOUTHEAST SO HAVE INCREASED CLOUDS THROUGH THE MORNING HOURS. RAP MODEL PICKING UP ON THIS THE BEST STILL AND BRINGS LOW CIGS ACROSS MY ENTIRE AREA BY MID MORNING. WILL MAINTAIN A LOW POP 12-18Z FOR LINGERING PRECIPITATION ACTIVITY AND ACROSS THE NORTH UNDERNEATH THE UPPER JET. MUCH COOLER FOR TODAY AS THE AFOREMENTIONED BOUNDARY CONTINUES TO TRACK SOUTH ACROSS THE STATE AND DUE TO LINGERING CLOUDINESS. TEMPERATURES TODAY PRETTY MUCH REMAIN STEADY...MAYBE WARMING A FEW DEGREES FROM THIS MORNING. TODAYS HIGHS MAY HAVE ALREADY OCCURRED SOME PLACES. MAINTAINED POPS THURSDAY AFTERNOON WEST WHEN PRECIPITATION ASSOCIATED WITH ANOTHER LEAD IMPULSE IS FORECAST TO DEVELOP NEAR THE INITIAL UPPER FORCING AND BAROCLINIC ZONE. STILL LOOKS LIKE MIXED PRECIPITATION WITH SFC TEMPS WEST LOW/MID 30S AND COOLING TEMPERATURES ALOFT. THE MAIN WINTER WEATHER ASSOCIATED WITH THE CURRENT WINTER WEATHER ADVISORY ARRIVES THURSDAY EVENING/OVERNIGHT INTO FRIDAY MORNING AND CONTINUES FRIDAY DAYTIME. WILL MAINTAIN THE CURRENT HEADLINES AS IS...WITH GENERAL 3 TO 5 INCH AMOUNTS ACROSS THE NORTHWEST AND NORTH CENTRAL THROUGH FRIDAY AFTERNOON. ISOLATED HIGHER AMOUNTS ARE POSSIBLE IN THE EXTREME NORTHWEST...NEAR CROSBY. LIGHTER AMOUNTS OF AN INCH OR TWO ARE POSSIBLE THROUGH FRIDAY AFTERNOON FROM BEACH AND DICKINSON...THROUGH GARRISON AND RUGBY. ANY WINTRY MIX WILL LIKELY BE CONFINED TO THE EXTREME SOUTHWEST AND SOUTH CENTRAL COUNTIES...NEAR AND SOUTH OF INTERSTATE 94 WHERE MODELS HINT AT SOME DRYING AIR ALOFT WORKING INTO THIS FIRST WAVE. PRESSURE GRADIENT TIGHTENS TONIGHT INTO FRIDAY RESULTING IN INCREASING EASTERLY WINDS. WILL NOT MENTION BLOWING SNOW YET AS STILL UNCERTAIN HOW WET THE SNOW WILL BE AND IF IT CAN EVEN BLOW AROUND. THE DAY SHIFT WILL WANT TO REEVALUATE. .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY STRONG SYSTEM MOVING ONTO THE NORTHERN PLAINS LATE IN THE WEEK AND INTO THE UPCOMING WEEKEND MAIN CONCERN THIS FORECAST. MODELS AND GUIDANCE IN FAIRLY GOOD AGREEMENT. CLOSED MID LEVEL DEVELOPS OVER ROCKY MOUNTAIN INTERIOR WITH SEVERAL WAVES OF ENERGY EJECTING FROM TROUGH AND MOVING THROUGH THE NORTHERN PLAINS. FIRST WAVE MOVES OVER TOP OF STRONG ISENTROPIC AND WEAK OROGRAPHIC LIFT ACROSS NORTHWEST NORTH DAKOTA OVERNIGHT ON THURSDAY WITH SEVERAL INCHES OF SNOW LIKELY FROM WILLISTON TO BOTTINEAU. MAIN SURFACE LOW MOVES ONTO THE NORTHERN AND CENTRAL PLAINS FRIDAY NIGHT WHEN BEST PRECIPITATION SHOULD OCCUR. WARM ADVECTION AHEAD OF AND WRAPPING AROUND THE NORTH SIDE OF THIS LOW WILL CREATE AREAS OF SNOW...SLEET AND FREEZING RAIN CENTRAL WITH HEAVIER BAND OF SNOW OVER NORTHERN COUNTIES AND RAIN OR FREEZING RAIN AT TIMES ACROSS THE SOUTHERN TIER OF COUNTIES. SATURDAY EVENING STRONG NORTHERLY WINDS WILL DEVELOP AS THE LOW MOVES TO THE EAST. AMOUNT OF BLOWING SNOW MAY BE LIMITED ESPECIALLY ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE AREA BUT MAY BECOME A PROBLEM NORTH THROUGH SATURDAY NIGHT. SUNDAY AND MONDAY PACIFIC HIGH PRESSURE MOVES OVER THE NORTHERN PLAINS BEFORE THE NEXT WEAKER SYSTEM IN ZONAL FLOW APPROACHES WESTERN DAKOTAS ON TUESDAY AND WEDNESDAY. TEMPERATURES WILL BE INFLUENCED BY THE AMOUNT OF SNOW COVER WE ESTABLISH. && AVIATION... BAND OF IFR AND MVFR CEILINGS ADVANCING SOUTH BEHIND A COLD FRONT THROUGH MOST OF THE FORECAST AREA. CONDITIONS WILL FURTHER DETERIORATE FURTHER AS NEXT SYSTEM MOVES INTO THE CENTRAL PLAINS AND PRECIPITATION DEVELOPS AGAIN TOMORROW NIGHT. && .BIS WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SUNDAY MORNING FOR NDZ013-019>023-025-033>037-040-041-043. WINTER STORM WARNING FROM 6 PM CST /5 PM MST/ FRIDAY TO NOON CST /11 AM MST/ SUNDAY FOR NDZ001>005-009>012-017-018-031-032. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 PM CST FRIDAY FOR NDZ001>004-009>011-017. && $$ SHORT TERM...NH LONG TERM/AVIATION...HW
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1025 PM MST WED NOV 7 2012 .AVIATION...00Z TAFS VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY EVENING. A COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT BRINGING NORTHWEST WINDS GUSTING TO 30KTS AT TIMES ACROSS THE SD PLAINS THROUGH THURSDAY MORNING. && .PREV DISCUSSION... /ISSUED 544 PM MST WED NOV 7 2012/ 00Z SURFACE ANALYSIS HAD COLD FRONT FROM NORTHEAST MT INTO SOUTH CENTRAL MT. 3-5MB/3HR PRESSURE RISES BEHIND IT...WHICH IS IN LINE WITH 21Z RAP. 21Z RAP HAS SOMEWHAT STRONGER WINDS BEHIND THE COLD FRONT FOR A FEW HOURS TONIGHT...SO WILL DO AN EARLY UPDATE TO ADDRESS. PREV DISCUSSION... /ISSUED 249 PM MST WED NOV 7 2012/ DISCUSSION...CURRENT SURFACE ANALYSIS PLACES LOW OVER NORTHEAST WYOMING INTO SOUTHERN SASKATCHEWAN. WARM SOUTHERLY FLOW OVER THE AREA HAS PUSHED HIGHS INTO THE 70S OVER MANY LOCATIONS. UPPER LEVEL ANALYSIS PLACES RIDGE OVER THE CTRL CONUS...WITH AXIS STRETCHING FROM COLORADO/NEW MEXICO INTO THE WRN DAKOTAS. TONIGHT...RIDGE AXIS SHIFTS TO THE EAST WHILE COOL FRONT SETTLES INTO THE AREA. WINDS MAY BRIEFLY BECOME BREEZY IN THE WAKE OF THE FRONT...OTHERWISE QUIET WEATHER IS EXPECTED. ON THURSDAY...TEMPERATURES WILL BE NOTABLY COOLER IN THE WAKE OF THE FRONT...WITH HIGHS RETURNING CLOSER TO AVERAGE. SOUTHWEST FLOW SETS UP OVER THE AREA AHEAD OF POTENT UPPER LOW SLIDING OVER THE WEST COAST TOWARDS THE ROCKIES. WEAK WAVE SLIDING AHEAD OF THE LOW CROSSES THE AREA LATE IN THE EVE. FORECAST SOUNDINGS SUGGEST RAIN/FREEZING RAIN WILL BE POSSIBLE OVER FAR NWRN SD...THOUGH CHANCES REMAIN QUITE LOW. FOR FRIDAY...UPPER LOW/TROF CONTINUES TO PUSH OVER THE ROCKIES WITH PRECIP SLOWLY DEVELOPING FROM NW TO SE OVER THE AREA. IT APPEARS THAT MOST OF THE LIFT WITH THIS SYSTEM WILL REMAIN TO THE NORTH/WEST...THOUGH SOME PRECIP WILL DEVELOP OVER OUR AREA WITH STRONG ISENTROPIC LIFT...PARTICULARLY OVER THE NWRN CWA IN THE EVENING. THE FORECAST FOR PRECIP TYPE REMAINS TRICKY AS FORECAST SOUNDINGS SUGGEST THE POSSIBILITY OF SOME FREEZING RAIN OVER NWRN/W CTRL SD WITH WARMER AIR ALOFT...CHANGING TO SNOW AS COOLER AIR TRIES TO WORK IN AS COLD FRONT PUSHES IN LATE. EXTENDED...UPPER LEVEL TROF WILL MOVE ACROSS THE PLAINS OVER THE WEEKEND. UPPER LOW DEVELOPING WITHIN THE TROF IS GENERALLY PROGGED TO PASS TO THE NORTHWEST AND NORTH OF THE CWA SATURDAY INTO SUNDAY. SURFACE LOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WY FRIDAY...PASS JUST SOUTH OF THE FORECAST AREA ON SATURDAY...AND THEN MOVE WELL EAST OF THE AREA BY SUNDAY. AS THE LOW PASSES THROUGH THE REGION...A STRONG COLD FRONT WILL DRAG MUCH COLDER AIR INTO THE AREA...WITH TEMPERATURES SLOWLY FALLING ON SATURDAY. A BAND OF STRONG FRONTOGENESIS ALONG AND BEHIND THE FRONT WILL HELP TO PRODUCE THE BULK OF THE PCPN...MOSTLY IN THE FORM OF SNOW OR RAIN CHANGING TO SNOW. A BRIEF PERIOD OF FREEZING RAIN...POSSIBLY SLEET...LOOKS POSSIBLE ON SATURDAY ACROSS PORTIONS OF WESTERN SD DURING THE TRANSITION. BASED ON THE CURRENT TRACK...SNOW AMOUNTS DO NOT LOOK TO BE SIGNIFICANT FROM THIS SYSTEM...WITH UP TO AN INCH OVER FAR NORTHWEST SOUTH DAKOTA. PCPN WILL DIMINISH SATURDAY NIGHT...WITH MOST IF NOT ALL PCPN OUT OF THE AREA SUNDAY MORNING. DRY WEATHER IS THEN EXPECTED THROUGH EARLY NEXT WEEK. COLD TEMPERATURES WILL REMAIN ACROSS THE AREA SUNDAY...WITH MILDER AIR RETURNING EARLY NEXT WEEK...ESPECIALLY ACROSS SOUTHERN AND WESTERN PORTIONS OF THE CWA. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...WFO UNR LONG TERM...WFO UNR AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CST WED NOV 7 2012 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT 314 PM CST WED NOV 7 2012 AT 3 PM...A SURFACE RIDGE WAS LOCATED FROM THE CENTRAL PLAINS TO NORTH NORTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. ON THE EASTERN SIDE OF THIS RIDGE...LOW LEVEL MOISTURE /BELOW 900 MB/ REMAINS TRAPPED BELOW A SUBSIDENCE INVERSION. BOTH THE 07.12Z GFS AND NAM/WRF SUGGEST THAT AS THE WINDS PICK UP ON WESTERN SIDE OF THIS RIDGE...THE MOISTURE LIFTS AND EVENTUALLY MIXES OUT AS BECOMES PROGRESSIVELY THINNER. THESE MODELS SHOW THAT THIS WILL INITIALLY OCCUR ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS EVENING...AND SPREAD ACROSS WESTERN WISCONSIN AFTER MIDNIGHT. MEANWHILE THE LATEST RAP IS INSISTENT THAT THESE LOW CLOUDS WILL PERSIST THROUGH THE NIGHT. WITH THE SATELLITE SHOWING VERY LITTLE CLOUDS ON THIS ON THE WESTERN SIDE OF THE RIDGE...WENT ALONG WITH THE GFS AND NAM/WRF. HOWEVER A BIT CONCERNED THAT THAT THE TIME OF DAY WOULD FAVOR THE RAP SOLUTION. EVENING SHIFT WILL HAVE TO WATCH THIS CLOSELY. IF THE CLOUDS DO NOT CLEAR...THE LOW TEMPERATURES WILL BE ABOUT 5 TO 7 DEGREES TOO COLD. ON THURSDAY AFTERNOON AND NIGHT...THE 07.12Z MODELS ARE IN GOOD AGREEMENT THAT A PACIFIC COLD FRONT WILL MOVE EAST THROUGH THE FORECAST AREA. WITH THE SURFACE LOW MOVING THROUGH ONTARIO AND DRY AIR /290-300K CONDENSATION DEFICITS GREATER THAN 100 MB/ BEING ADVECTED OFF OF THE CENTRAL PLAINS AHEAD OF THIS SYSTEM...NOT EXPECTING TOO MUCH CLOUDS OR PRECIPITATION FROM THIS FRONT. ON FRIDAY AFTERNOON AND NIGHT...THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT WAVE TROUGH WILL EJECT OUT OF WESTERN UNITED STATES LONG WAVE TROUGH. AS THIS WAVES APPROACHES WEAK TO MODERATE 290-300K ISENTROPIC LIFT DEVELOPS OVER THE AREA. THE CONDENSATION DEFICITS SLOWLY DROP FROM OVER 100 MB ON FRIDAY AFTERNOON TO 20 TO 50 MBS BY SATURDAY MORNING. IN ADDITION...MODERATE 850 MB TRANSPORT WILL BE DEVELOPING ACROSS THE AREA ON FRIDAY NIGHT. THE NAM/WRF IS THE SLOWEST AT SATURATING THE ATMOSPHERIC COLUMN. AS A RESULT...IT DOES NOT GENERATE ANY PRECIPITATION UNTIL IT GETS OVER NORTHERN MINNESOTA AND FAR NORTHERN WISCONSIN. MEANWHILE THE GEM...GFS...AND ECMWF HAS THE PRECIPITATION DEVELOPING OVER OUR AREA. SINCE THE RUN TO RUN VARIABILITY HAS REMAINED INCONSISTENT... KEPT PRECIPITATION CHANCES IN THE 20 TO 40 PERCENT RANGE. WITH BOTH THE ECMWF AND NAM/WRF SUGGESTING MLCAPES WILL UP TO 400 J/KG ALONG AND NORTH OF THE WARM FRONT AFTER MIDNIGHT...ADDED ISOLATED THUNDERSTORMS TO THE FORECAST. .LONG TERM...SATURDAY THROUGH WEDNESDAY 314 PM CST WED NOV 7 2012 ON SATURDAY...THE 07.12Z MODELS ARE IN GOOD AGREEMENT THAT THE AREA WILL ENTER THE WARM SECTOR OF THE LOW PRESSURE SYSTEM. WHILE THIS IS THE CASE...THEY DO DIFFER ON THE STRENGTH OF THE CAP. THE NAM/WRF AND GEM HAVE THE STRONGEST CAP...THUS...NO PRECIPITATION. MEANWHILE THE GFS AND ECMWF SHOW A WEAKER CAP WHICH ALLOWS FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO CONTINUE THROUGHPUT THE DAY. SINCE THE MODELS HAVE VERY CONSISTENT WITH THIS TIME PERIOD...JUST KEPT THE PRECIPITATION CHANCES IN THE 20 TO 40 PERCENT RANGE. THIS PRECIPITATION ALSO AFFECTS THE AMOUNT OF INSTABILITY THAT CAN DEVELOP AHEAD OF THE APPROACHING COLD FRONT. WITH NO PRECIPITATION...THE MLCAPES CLIMB TO AROUND 600 J/KG IN THE NAM/WRF. MEANWHILE THE PRECIPITATION THE GFS AND ECMWF LIMITS THE MLCAPES TO LESS THAN 300 J/KG. THE 0-6 KM SHEAR IS FAVORABLE IN ALL 3 MODELS FOR MINI SUPERCELL DEVELOPMENT. HOWEVER A MAJORITY OF THIS SHEAR IS LOCATED IN THE 0-1 KM LAYER. IF THE THUNDERSTORMS DO NOT BECOME SURFACE BASED...THESE STORMS WILL ONLY HAVE LESS THAN 20 KNOTS OF SHEAR TO WORK WITH AND AS A RESULT THEY WOULD NOT HAVE ADEQUATE SHEAR TO ORGANIZE THEMSELVES INTO MINI SUPERCELLS. THE OTHER FORECAST CHALLENGE ON SATURDAY IS HOW WARM THE AREA WILL GET. 850 MB STANDARDIZED ANOMALIES ARE 1 TO 1.5 STANDARD DEVIATIONS ABOVE NORMAL. THE NAM/WRF HAS LITTLE CLOUDS IN THE WARM SECTOR WHICH ALLOWS THE HIGH TEMPERATURES TO RANGE FROM THE LOWER 60S TO LOWER 70S. MEANWHILE THE ECMWF HAS MORE CLOUD COVER AND ITS TEMPERATURES RANGE FROM THE LOWER 50S TO LOWER 70S. WITH SUCH UNCERTAINTY STAYED WITH THE ALL BLEND WHICH HAS HIGH TEMPERATURES RANGING FROM THE MID 50S TO UPPER 60S. FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE MODELS ARE IN GOOD AGREEMENT THAT A STRONG COLD FRONT WILL MOVE THROUGH THE REGION. STRONG PV ADVECTION AND FRONTOGENESIS WILL RESULT IN WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE AREA. WHILE THIS HAS BEEN A CONSISTENT SIGNAL...THE MODELS HAVE SHOWN SOME TIMING DIFFERENCES OVER THE PAST COUPLE OF DAYS...THUS...KEPT PRECIPITATION PROBABILITIES IN THE 55 TO 74 RANGE. TEMPERATURES IN THE WAKE OF THIS FRONT WILL QUICKLY FALL INTO THE 30S. SOUNDINGS ALOFT SUGGEST THAT THERE WILL BE SOME ICE CRYSTALS BEING INTRODUCED FROM ALOFT...THUS...SOME SNOW STILL LOOKS POSSIBLE FROM SUNDAY AFTERNOON INTO SUNDAY NIGHT. ANY ACCUMULATIONS WILL BE HIGHLY DEPENDENT UPON HOW FAST THIS RAIN TO SNOW TRANSITION OCCURS. FROM LATE SUNDAY NIGHT INTO MONDAY...IT APPEARS THAT THE 07.12Z MODELS ARE MUCH FASTER THAN THEIR PREDECESSORS AT MOVING THE PRECIPITATION OUT OF THE AREA. WANTED TO FOLLOW THEM...BUT COULD NOT GET ENOUGH CONSENSUS TO GO AWAY FROM THE ALL BLEND MODEL. && .AVIATION...THROUGH 06Z FRIDAY 1135 PM CST WED NOV 7 2012 FORECAST CHALLENGE REMAINS ON CLEARING STRATUS THROUGH THE OVERNIGHT HOURS. BACK EDGE OF AN HIGHER END MVFR/LOWER END VFR DECK NOW APPROACHING KRST. MODELS CONSISTENT IN TAKING THIS BACK EDGE EASTWARD OVERNIGHT AS GRADIENT TIGHTENS AND WINDS PICK UP. MAY EVEN SEE SOME ACCELERATION. EXPECT THE LOWER DECK TO SCATTER OUT AROUND 07Z AT KRST AND 09Z AT KLSE. AFTER THAT ONLY SOME HIGH CLOUDS ARE EXPECTED AT BOTH TAF SITES. PRESSURE GRADIENT DOES TIGHTEN AND BUFKIT SOUNDINGS SHOWING MIXING TO BEGIN AROUND 13Z- 15Z. WOULD EXPECT SOME GUSTS AT KRST IN THE 20 TO 25 KNOT RANGE AND ONLY 15 TO 18 KNOTS AT KLSE. THESE WILL DIMINISH AROUND 00Z. && .ARX WATCHES/WARNINGS/ADVISORIES... 200 PM CST WED NOV 7 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
834 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * IMPROVEMENT OF MVFR VSBY TO AOB 6SM DURING MID-LATE MORNING. * IMPROVEMENT OF HI END MVFR CIGS TO VFR DURING MID-LATE MORNING. KREIN //DISCUSSION...UPDATED 14Z... CONDITIONS AT ORD AND MDW SHOWED LITTLE OR NO CHANGE OVER LAST COUPLE HRS. LOCATIONS ACROSS N CENTRAL IL INCLUDING DKB...RPJ AND VYS HAVE HI END MVFR CIGS BUT P6SM VSBYS AS GRADUALLY INCREASING SW LLVL FLOW HAS BEEN ADVECTING IN SOMEWHAT LOWER DWPTS. HOWEVER...TO SW-SSW OF ORD AND MDW DWPTS STILL IN UPR 30S-LWR 40S WITH MVFR CIGS AND VSBYS AT LOT...C09...PNT...BMI AND AAA SO BELIEVE WILL TAKE A COUPLE HRS BEFORE WE SEE IMPROVEMENT VFR CIGS AND VSBYS. TRS PREVIOUS DISCUSSION...UPDATED 12Z... MAIN CONCERN FOR EARLY THIS MORNING WILL FOCUS ON CIGS/VIS. LATEST SATELLITE IMAGERY SHOWS THAT THE PERSISTENT AREA OF ST OVER IL/WI IS MOVING TO THE EAST...WITH THE WESTERN EDGE CROSSING THE MISSISSIPPI RIVER INTO NWRN IL. THE TREND FOR THE CLOUD COVER SHOULD BE TO THIN THROUGH THE MORNING AS THE SFC RIDGE AXIS MOVES EWD ACROSS THE REGION. THE AREAS OF 2-4SM BR SHOULD PERSIST FOR A COUPLE HOURS AFTER SUNRISE AS WINDS REMAIN LGT/VRBL...BUT SOME WARMING COMBINED WITH THINNING OF THE ST LAYER SHOULD ALLOW VIS TO IMPROVE TO VFR. SINCE THE ST LAYER HAS REMAINED THICK ENOUGH TO SUPPRESS RADIATIVE COOLING...DO NOT EXPECT VISIBILITY TO DROP ANY LOWER THAN THAT WHICH IS OCCURRING AT ISSUANCE TIME. CONDITIONS SHOULD BE RATHER QUIET AT THE TERMINALS THROUGH THE DAY WITH LIGHT WINDS PERSISTING THROUGH THE REMAINDER OF THE MORNING HOURS. WINDS SHOULD STRENGTHEN BY LATE MORNING/EARLY AFTERNOON AND BECOME MORE SLY-SWLY AS A TROUGH OF LOW PRESSURE MOVES EWD ACROSS THE PLAINS. EXPECT THAT WINDS SHOULD INCREASE TO ARND 10KT...WITH SOME OCNL HIGHER GUSTS THROUGH THE AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MODERATE CONFIDENCE IN CIG AND VIS IMPROVEMENT TO VFR BY 16Z. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 315 AM CST A RIDGE OF HIGH PRESSURE OVER THE CENTRAL AND EASTERN GREAT LAKES WILL WILL KEEP RELATIVELY LIGHT WINDS OVER LAKE MICHIGAN THIS MORNING. AS THE HIGH SAGS SOUTHEASTWARD ACROSS THE OHIO VALLEY TODAY AND A WEAK TROUGH OF LOW PRESSURE MOVES INTO THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON...WINDS OVER THE LAKE WILL BECOME SOUTHWESTERLY AND STRENGTHEN. THE PRESSURE GRADIENT WILL BE STRONGEST OVER THE NORTHERN PORTIONS TO THE LAKE WITH WINDS INCREASING TO 15 TO 25 KT. WINDS OVER THE SOUTHERN PORTIONS OF THE LAKE WILL BE A BIT WEAKER...AROUND 10 TO 15 KT. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND DEEPEN AS IT TRACKS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL STRENGTHEN TO 30KT ACROSS THE LAKE...AND DURING THE PERIOD WHEN THE LOW IS DEEPENING OVER NRN WISCONSIN AND WESTERN LAKE SUPERIOR...THERE WILL BE A CHANCE FOR SOME 35KT GALE FORCE GUSTS SATURDAY NIGHT AND SUNDAY MORNING. AS THE LOW TRACKS NORTHEAST TO JAMES BAY SUNDAY NIGHT...IT WILL DRAG A STRONG COLD FRONT ACROSS LAKE MICHIGAN...TURNING WINDS WESTERLY TO NORTHWESTERLY. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
545 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * VIS 2-4SM IN BR OVERNIGHT. * LOWER VFR CIGS OVC035-040...POSSIBLY SCATTERING OUT DURG THE EARLY MORNING HOURS. KREIN //DISCUSSION...UPDATED 12Z... MAIN CONCERN FOR EALY THIS MORNING WILL FOCUS ON CIGS/VIS. LATEST SATELLITE IMAGERY SHOWS THAT THE PERSISTENT AREA OF ST OVER IL/WI IS MOVING TO THE EAST...WITH THE WESTERN EDGE CROSSING THE MISSISSIPPI RIVER INTO NWRN IL. THE TREND FOR THE CLOUD COVER SHOULD BE TO THIN THROUGH THE MORNINGAS THE SFC RIDGE AXIS MOVES EWD ACROSS THE REGION. THE AREAS OF 2-4SM BR SHOULD PERSIST FOR A COUPLE HOURS AFTER SUNRISE AS WINDS REMAIN LGT/VRBL...BUT SOME WARMING COMBINED WITH THINNING OF THE ST LAYER SHOULD ALLOW VIS TO IMPROVE TO VFR. SINCE THE ST LAYER HAS REMAINED THICK ENOUGH TO SUPPRESS RADIATIVE COOLING...DO NOT EXPECT VISIBILITY TO DROP ANY LOWER THAN THAT WHICH IS OCCURRING AT ISSUANCE TIME. CONDITIONS SHOULD BE RATHER QUIET AT THE TERMINALS THROUGH THE DAY WITH LIGHT WINDS PERSISTING THROUGH THE REMAINDER OF THE MORNING HOURS. WINDS SHOULD STRENGTHEN BY LATE MORNING/EARLY AFTERNOON AND BECOME MORE SLY-SWLY AS A TROUGH OF LOW PRESSURE MOVES EWD ACROSS THE PLAINS. EXPECT THAT WINDS SHOULD INCREASE TO ARND 10KT...WITH SOME OCNL HIGHER GUSTS THROUGH THE AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MODERATE CONFIDENCE IN CIG/VIS TRENDS THIS MORNING. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 315 AM CST A RIDGE OF HIGH PRESSURE OVER THE CENTRAL AND EASTERN GREAT LAKES WILL WILL KEEP RELATIVELY LIGHT WINDS OVER LAKE MICHIGAN THIS MORNING. AS THE HIGH SAGS SOUTHEASTWARD ACROSS THE OHIO VALLEY TODAY AND A WEAK TROUGH OF LOW PRESSURE MOVES INTO THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON...WINDS OVER THE LAKE WILL BECOME SOUTHWESTERLY AND STRENGTHEN. THE PRESSURE GRADIENT WILL BE STRONGEST OVER THE NORTHERN PORTIONS TO THE LAKE WITH WINDS INCREASING TO 15 TO 25 KT. WINDS OVER THE SOUTHERN PORTIONS OF THE LAKE WILL BE A BIT WEAKER...AROUND 10 TO 15 KT. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND DEEPEN AS IT TRACKS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL STRENGTHEN TO 30KT ACROSS THE LAKE...AND DURING THE PERIOD WHEN THE LOW IS DEEPENING OVER NRN WISCONSIN AND WESTERN LAKE SUPERIOR...THERE WILL BE A CHANCE FOR SOME 35KT GALE FORCE GUSTS SATURDAY NIGHT AND SUNDAY MORNING. AS THE LOW TRACKS NORTHEAST TO JAMES BAY SUNDAY NIGHT...IT WILL DRAG A STRONG COLD FRONT ACROSS LAKE MICHIGAN...TURNING WINDS WESTERLY TO NORTHWESTERLY. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
525 AM CST THU NOV 8 2012 .AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION FORECAST CONCERN IS THE APPROACH OF THE SURFACE FRONT FROM THE WEST AT KRSL/KSLN. SOUTHERLY FLOW WILL PERSIST ACROSS THE AREA FOR MUCH OF THE TERMINALS. AFTERNOON WINDS ARE EXPECTED TO BE GUSTY WITH 15-20 KTS SUSTAINED AND GUSTS UPWARDS TO 30KTS. HOWEVER...AT KRSL AND KSLN THE SURFACE LOW WILL APPROACH AND THE BOUNDARY WILL BE IN THE AREA...THIS HAS ALREADY CAUSED WINDS AT KRSL TO DECREASE AS OF 11Z. THINK WINDS WILL BE WEAK...BUT SOUTHERLY AT KRSL THROUGH THE AFTERNOON...BUT AS THE EVENING APPROACHES THE WINDS WILL BE COME VARIABLE. SIMILAR THING EXPECTED AT KSLN...BUT TIMING IS DELAYED UNTIL LATER THIS AFTERNOON AND AFTER DARK. DESPITE THE WIND DIRECTION ISSUES AT KRSL/KSLN VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST AT ALL TERMINALS. BILLINGS && .PREV DISCUSSION... /ISSUED 323 AM CST THU NOV 8 2012/ DISCUSSION... TODAY-FRI: MAIN FOCUS IS ON MOISTURE RETURN AHEAD OF APPROACHING FRONT. GFS STILL APPEARS TO BE RUNNING MOIST...AND ALTHOUGH NAM EVOLUTION LOOKS GOOD...ITS ALREADY TOO FAST GIVEN OBSERVED SURFACE DEW POINTS ACROSS TX. HAVE TRENDED CLOSER TO RUC THIS MORNING AND THEN NAM/EC BLEND INTO FRI. GUSTY SOUTH WINDS ARE EXPECTED AS SURFACE PRESSURE GRADIENT INCREASES. COMBO OF POTENTIAL LOW CLOUDS AND INCREASING CIRRUS WILL MAKE BOTH MINIMUM/MAXIMUM TEMPERATURES TRICKY THIS PERIOD. EXPECT WINDS TO KEEP TEMPERATURES UP TONIGHT. BETTER CHANCE OF CLOUDS ON FRI MAY LIMIT WARMUP EAST OF I-35...WITH BIG WARMUP POSSIBLE ROUGHLY WEST OF HIGHWAY 14 WITH LOWER DEW POINTS AND MORE WEST/DOWNSLOPE WIND COMPONENT. SAT-SUN: OUTSIDE CHANCE THAT PRECIPITATION COULD BREAK OUT IN THETA-E ADVECTION ACROSS NORTHWEST SECTIONS OF FORECAST AREA SAT AFTERNOON...BUT CHANCES SHOULD RAMP UP SAT NIGHT-SUN AS FRONT MOVES THROUGH. NOW APPEARS THAT PRECIPITATION WOULD LIKELY END BEFORE FREEZING TEMPERATURES ARRIVE IN CENTRAL KS AND HAVE DROPPED MENTION OF SNOW AROUND DAYBREAK SUN FOR NOW. BY SUN MOST OF PRECIPITATION WILL BE EAST OF I-35...BUT TIMING IS A BIT QUESTIONABLE WITH FAIR AMOUNT DISCREPANCIES BETWEEN MODELS. PRECIPITATION MIGHT LINGER IN FAR SOUTHEAST SECTIONS INTO SUN NIGHT...BUT SUSPECT WOULD LIKELY BE LIMITED IN TIME AND SPACE. MUCH COLDER AIR WILL BE MOVING INTO THE AREA BEHIND THE FRONT. MON-WED: DRY CONDITION LIKELY THIS PERIOD. WITH BOTH GFS/ECMWF SHOWING UPPER FLOW BECOMING INCREASINGLY ZONAL THROUGH THIS PERIOD...EXPECT FAIRLY RAPID RECOVERY IN TEMPERATURES. HAVE NUDGED UP INITIALIZATION TEMPERATURES...ESPECIALLY ON WED FOR THIS. POTENTIAL IS EVEN WARMER. HOWEVER BOTH GFS/ECMWF SUGGEST THERE COULD BE FAIR AMOUNT OF CIRRUS IN THE AREA WITH THE LEFT FRONT QUADRANT OF APPROACHING 300MB SPEED MAXIMUM AND RELATIVELY LOW SUN ANGLE. -HOWERTON AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU A RIDGE OF HIGH PRESSURE ALOFT WILL RESULT IN TRANQUIL WEATHER ACROSS THE CENTRAL AND SOUTHERN PLAINS WHILE A TROUGH OF LOW PRESSURE AT THE SURFACE REMAINS ANCHORED OVER THE SOUTHERN HIGH PLAINS. THIS WILL RESULT IN INCREASING SOUTHERLY WINDS THROUGH THE DAY ON THURSDAY WITH GUSTS TO AROUND 30 KNOTS ANTICIPATED. MWM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 73 56 77 62 / 0 0 0 10 HUTCHINSON 70 55 78 59 / 0 0 0 10 NEWTON 69 56 76 59 / 0 0 0 10 ELDORADO 72 59 75 61 / 0 0 10 10 WINFIELD-KWLD 73 61 76 63 / 0 0 0 10 RUSSELL 65 45 81 57 / 0 0 0 10 GREAT BEND 69 45 82 58 / 0 0 0 10 SALINA 70 52 80 60 / 0 0 0 10 MCPHERSON 70 54 78 59 / 0 0 0 10 COFFEYVILLE 73 58 76 64 / 0 0 10 10 CHANUTE 69 56 75 60 / 0 0 10 10 IOLA 68 55 75 61 / 0 0 10 10 PARSONS-KPPF 70 60 76 62 / 0 0 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
959 AM EST THU NOV 8 2012 .UPDATE... ISSUED AT 951 AM EST THU NOV 8 2012 LIGHT WARM ADVECTION /LIFT ON 295K SURFACE/ PRECIPITATION CONTINUES TO PUSH EAST THIS MORNING. MORNING INL/GRB/APX SOUNDING CONTINUES TO SHOW A REMNANT DRY WEDGE CENTERED AT H8...WHICH SUGGESTS THAT ANY OF THE RETURNS SEEN ON THE MQT 88D ARE LIKELY NO MORE THAN SPRINKLES. BEST ISENTROPIC ASCENT WILL CONTINUE TO SHIFT EAST AS THE DAY GOES ON...SO EXPECT ANY SPRINKLES TO GIVE WAY TO A DRY AFTERNOON. WITH THE BEST MOISTURE SHIFTING EAST AS THE DAY GOES ON...AND LOOKING AT UPSTREAM OBS OVER NORTHEAST MINNESOTA...SKIES WILL GRADUALLY IMPROVE /IWD ALREADY CLEARING AT THIS HOUR/...WITH PARTLY SUNNY SKIES OVERTAKING MOST OF THE CWA DURING THE AFTERNOON. CLOUDS WILL BE MOST STUBBORN OVER FAR EASTERN AREAS WITH MOIST PLUME OFF OF LAKE MICHIGAN POTENTIALLY IMPACTING MY FAR EASTERN ZONES THROUGH THE DAY GIVEN SOUTHWESTERLY LLEVEL FLOW. GOING FORECAST HAD THESE TRENDS WELL-HANDLED WITH ONLY MINOR TWEAKS TO POP/SKY TIMING. TEMPERATURES IN THE MID 40S EAST /MORE CLOUDS/ TO AROUND 50 WEST GIVEN T92S WARMING TO +2-4C IN THE AFOREMENTIONED WARM ADVECTION REGIME. UPDATE ISSUED AT 654 AM EST THU NOV 8 2012 SOME OF THE SHORTER SCALE FCST MODELS ARE HAVING A BETTER TIME HANDLING THE CURRENT SHOWER ACTIVITY OVER FAR W UPPER MI. UPDATED THE FCST /POPS/WX/QPF...WITH ASSISTANCE OF THE RUC GUIDANCE WHICH && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EST THU NOV 8 2012 ALTHOUGH MUCH OF THE ENERGY WITH THE WEAK SHORTWAVE IS CROSSING TO OUR NORTH...INCREASED MOISTURE AHEAD OF THE NEXT SFC LOW OVER THE DAKOTAS HAS ALLOWED FOR A BROKEN LINE OF SHOWERS TO DEVELOP. AS OF 09Z NO CLOUD TO GROUND LIGHTNING HAS BEEN FOUND WITH THIS SYSTEM. WHILE TEMPERATURES ALOFT WOULD SUPPORT RAIN SHOWERS /850MB TEMPS OF 0-3C OVER N WI EARLY THIS MORNING/...POCKETS OF COOLER AIR NEAR THE SFC COULD RESULT IN LIGHT FREEZING RAIN. AT6 09Z THE ONLY LOCATIONS SHOWING UP ON THE MESONET BELOW FREEZING WERE PEAVY FALLS AND RANDVILLE...JUST NW OF IRON MOUNTAIN. TEMPS SHOULD NOT FALL MORE THAN ANOTHER DEGREE BEFORE SUNRISE. ADDED ISOLATED FREEZING RAIN...BUT THE POTENTIAL REMAINS SMALL AT THIS TIME. AS A RESULT...WILL NOT ISSUE ANY SPS AT THIS TIME GIVEN THE PRECIP JUST STARTING TO CROSS THE BOARDER INTO CWA. THE POTENTIAL EXISTS FOR ANOTHER BAND OF MAINLY RAIN SHOWERS TO DEVELOP OVER THE E PORTIONS OF THE CWA...WITH FAVORABLE SE FLOW OFF LAKE SUPERIOR...AS MUCH OF THE INITIAL EARLY MORE SHOWER ACTIVITY PUSHES ENE INTO LAKE SUPERIOR. S-SW FLOW AND 850MB TEMPS RISING TO 3-6C OVER THE CENTRAL PORTIONS OF THE CWA SHOULD ALLOW TEMPS FROM BARAGA THROUGH AT LEAST MARQUETTE COUNTY TO BE A COUPLE DEGREES ABOVE WHAT THEY WOULD OTHERWISE BE THANKS TO DOWNSLOPE FLOW. AS FOR TONIGHT...LIGHTER WINDS SHOULD BE THE RULE AS THE FRONTAL BOUNDARY STRETCHING FROM LOWS OVER HUDSON BAY AND THE CENTRAL PLAINS SHIFTS FROM THE FAR W CWA TO OUR SE BY 12Z FRIDAY. THE MOISTURE PROFILE REMAINS PRETTY SHALLOW OVERNIGHT. STILL...A COUPLE OF FCST MODELS ARE INDICATING THE POTENTIAL FOR MIXED PRECIP /MAINLY RAIN OR FREEZING RAIN/ OVER N CENTRAL UPPER MI JUST PRIOR TO SUNRISE FRIDAY. WILL NOT PLACE THIS IN THE FORECAST QUITE YET...DUE TO THE UNCERTAINTY AND LIMITED PRECIP IF IT DOES HAPPEN...AROUND TRACE TO 0.01 INCHES OF LIQUID. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 533 AM EST THU NOV 8 2012 FRI INTO SAT...THE MID/UPPER LEVEL TROUGH OVER THE WEST COAST IS EXPECTED TO SLIDE EAST INTO THE GREAT BASIN AND ROCKIES RESULTING IN SW FLOW FROM THE PLAINS INTO THE NRN GREAT LAKES. AT THE SFC...AN AREA OF LOW PRES OVER THE ROCKIES WILL MOVE INTO THE CENTRAL PLAINS AND INTO MN. LOW LEVEL ERLY FLOW WILL STRENGTHEN AS THE PRES GRADIENT INCREASES BTWN A WARM FRONT LIFTING TO THE NORTH FROM WI AND A RIDGE FROM NRN SASK INTO NRN ONTARIO. EVEN THOUGH THE MODELS HAVE HINTED AT THE POTENTIAL FOR SOME PATCHY LIGHT RAIN OR DRIZZLE FRIDAY...WITH MAINLY WEAK ACYC FLOW PREVAILING AND ONLY WEAK LOW LEVEL UPWARD MOTION...CONFIDENCE WAS LOW THAT ANY MEASURABLE PCPN WILL DEVELOP. THE BEST CHANCE FOR ANY PCPN WOULD BE IN UPSLOPE LOCATIONS DOWNWIND OF LAKE SUPERIOR LATE IN THE DAY. AS THE LOW LIFTS INTO MN AND THE 850 WARM FRONT OVER WI LIFTS THROUGH UPPER MI...A BAND OF 295K-305K ISENTROPIC LIFT WILL STRENGTHEN ENOUGH TO SUPPORT LIKELY RAIN CHANCES THROUGH UPPER MI BY SATURDAY MORNING. WITH MUCAPE VALUES TO AROUND 400 J/KG BY SATURDAY AFTERNOON SOME TSRA MAY BE POSSIBLE. SAT NIGHT...AS THE LOW LIFTS THROUGH MN TO NEAR CYQT THE FOCUS FOR STRONGER ISENTROPIC LIFT ALONG THE 850-700 MB FRONT WILL ALOS LIFT NORTH OF THE AREA. HOWEVER...SOME SHOWERS WILL STILL BE POSSIBLE IN THE WARM SECTOR AS WEAK SHORTWAVES ARE LIKELY TO MOVE THROUGH THE AREA. SUN...THE BEST CHANCE FOR WIDEPSREAD MODERATE TO OCNLY HEAVY RAIN WILL BE ALONG THE COLD FRONT AS THE LOW LIFT TOWARDS JAMES BAY AND MOISTURE TRANSPORT PUSHES PWAT VALUES TO 1.00-1.25 INCH...250-300 PCT OF NORMAL. MUCAPE VALUES TO AROUND 400 J/KG ALSO SUGGEST THAT ISOLD TSRA WILL REMAIN POSSIBLE. GIVEN THE HIGH AMPLITUDE PATTERN...THE SLOWER ECMWF WAS PREFERRED WITH THE TIMING OF THE FRONT COMPARED TO THE GFS. MON INTO TUE...A PERIOD OF LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY WNW TO NW FLOW IS EXPECTED AS CAA DROPS 850 MB TEMPS TO AROUND -12C. THE GEFS/GFS AND ECMWF WERE SIMILAR WITH A QUICK TRANSITION TO MORE ZONAL FLOW BY TUE NIGHT WHICH WOULD END LES POTENTIAL AND BRING && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 547 AM EST THU NOV 8 2012 INCREASED MIXING AND DOWNSLOPE SW WINDS AT IWD AND SAW SHOULD HELP KEEP CEILINGS IN THE VFR RANGE THROUGH THE EVENING HOURS. WINDS WILL BE ON THE INCREASE...WITH GUSTS IN THE 18-22KT RANGE AT IWD AND SAW DURING THE EARLY AFTERNOON HOURS...JUST AHEAD OF THE NEARING COLD FRONT FROM THE WNW. ADDITIONAL MOISTURE WILL SLIP IN OVERNIGHT...AT OR BELOW 5KFT...BEHIND THE EXITING FRONTAL BOUNDARY AS WINDS SLOWLY TURN W AND THEN MAINLY OUT OF A N DIRECTION PRIOR TO DAYBREAK FRIDAY. WHILE LITTLE TO NO PRECIP IS EXPECTED WITH THE FRONT...FLIGHT CATEGORIES WILL LIKELY FALL INTO THE MVFR RANGE AT BOTH SAW AND IWD...WHILE REMAINING VFR AT CMX GIVEN THE LESS && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST THU NOV 8 2012 THE RIDGE OF HIGH PRESSURE OVER LAKE MI AND LAKE HURON WILL CONTINUE TO PUSH E AS A LOW ACROSS NW MN MOVES TO JAMES BAY THIS AFTERNOON. THIS WILL ALLOW A TROUGH TO SWING ACROSS SLAKE SUPERIOR TONIGHT. THIS WILL ALLOW S-SE GUSTS OF 25-30KTS OVER THE E THIRD OF LS. A RIDGE WILL TEMPORARILY BUILD ACROSS LS BEHIND THE TROUGH ON FRIDAY...WITH FUNNELING NE WINDS ACROSS W LS GUSTING 20-30KTS WOUND NOT BE OUT OF THE QUESTION FRIDAY THROUGH SATURDAY. A FEW GALE FORCE GUSTS MAY NEED TO BE MENTIONED FAR W SATURDAY. A DEEPER LOW ACROSS THE CENTRAL PLAINS SATURDAY MORNING WILL CROSS LS LATE SATURDAY && .MQT WATCHES/WARNINGS/ADVISORIES... MI...NONE. LS...NONE. LM...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST FRIDAY FOR LMZ248-250. && $$ UPDATE...ARNOTT SHORT TERM...KF LONG TERM...JLB AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
655 AM EST THU NOV 8 2012 .UPDATE... ISSUED AT 654 AM EST THU NOV 8 2012 SOME OF THE SHORTER SCALE FCST MODELS ARE HAVING A BETTER TIME HANDLING THE CURRENT SHOWER ACTIVITY OVER FAR W UPPER MI. UPDATED THE FCST /POPS/WX/QPF...WITH ASSISTANCE OF THE RUC GUIDANCE WHICH SEEMS TO BE THE BEST OF THE BUNCH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EST THU NOV 8 2012 ALTHOUGH MUCH OF THE ENERGY WITH THE WEAK SHORTWAVE IS CROSSING TO OUR NORTH...INCREASED MOISTURE AHEAD OF THE NEXT SFC LOW OVER THE DAKOTAS HAS ALLOWED FOR A BROKEN LINE OF SHOWERS TO DEVELOP. AS OF 09Z NO CLOUD TO GROUND LIGHTNING HAS BEEN FOUND WITH THIS SYSTEM. WHILE TEMPERATURES ALOFT WOULD SUPPORT RAIN SHOWERS /850MB TEMPS OF 0-3C OVER N WI EARLY THIS MORNING/...POCKETS OF COOLER AIR NEAR THE SFC COULD RESULT IN LIGHT FREEZING RAIN. AT6 09Z THE ONLY LOCATIONS SHOWING UP ON THE MESONET BELOW FREEZING WERE PEAVY FALLS AND RANDVILLE...JUST NW OF IRON MOUNTAIN. TEMPS SHOULD NOT FALL MORE THAN ANOTHER DEGREE BEFORE SUNRISE. ADDED ISOLATED FREEZING RAIN...BUT THE POTENTIAL REMAINS SMALL AT THIS TIME. AS A RESULT...WILL NOT ISSUE ANY SPS AT THIS TIME GIVEN THE PRECIP JUST STARTING TO CROSS THE BOARDER INTO CWA. THE POTENTIAL EXISTS FOR ANOTHER BAND OF MAINLY RAIN SHOWERS TO DEVELOP OVER THE E PORTIONS OF THE CWA...WITH FAVORABLE SE FLOW OFF LAKE SUPERIOR...AS MUCH OF THE INITIAL EARLY MORE SHOWER ACTIVITY PUSHES ENE INTO LAKE SUPERIOR. S-SW FLOW AND 850MB TEMPS RISING TO 3-6C OVER THE CENTRAL PORTIONS OF THE CWA SHOULD ALLOW TEMPS FROM BARAGA THROUGH AT LEAST MARQUETTE COUNTY TO BE A COUPLE DEGREES ABOVE WHAT THEY WOULD OTHERWISE BE THANKS TO DOWNSLOPE FLOW. AS FOR TONIGHT...LIGHTER WINDS SHOULD BE THE RULE AS THE FRONTAL BOUNDARY STRETCHING FROM LOWS OVER HUDSON BAY AND THE CENTRAL PLAINS SHIFTS FROM THE FAR W CWA TO OUR SE BY 12Z FRIDAY. THE MOISTURE PROFILE REMAINS PRETTY SHALLOW OVERNIGHT. STILL...A COUPLE OF FCST MODELS ARE INDICATING THE POTENTIAL FOR MIXED PRECIP /MAINLY RAIN OR FREEZING RAIN/ OVER N CENTRAL UPPER MI JUST PRIOR TO SUNRISE FRIDAY. WILL NOT PLACE THIS IN THE FORECAST QUITE YET...DUE TO THE UNCERTAINTY AND LIMITED PRECIP IF IT DOES HAPPEN...AROUND TRACE TO 0.01 INCHES OF LIQUID. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 533 AM EST THU NOV 8 2012 FRI INTO SAT...THE MID/UPPER LEVEL TROUGH OVER THE WEST COAST IS EXPECTED TO SLIDE EAST INTO THE GREAT BASIN AND ROCKIES RESULTING IN SW FLOW FROM THE PLAINS INTO THE NRN GREAT LAKES. AT THE SFC...AN AREA OF LOW PRES OVER THE ROCKIES WILL MOVE INTO THE CENTRAL PLAINS AND INTO MN. LOW LEVEL ERLY FLOW WILL STRENGTHEN AS THE PRES GRADIENT INCREASES BTWN A WARM FRONT LIFTING TO THE NORTH FROM WI AND A RIDGE FROM NRN SASK INTO NRN ONTARIO. EVEN THOUGH THE MODELS HAVE HINTED AT THE POTENTIAL FOR SOME PATCHY LIGHT RAIN OR DRIZZLE FRIDAY...WITH MAINLY WEAK ACYC FLOW PREVAILING AND ONLY WEAK LOW LEVEL UPWARD MOTION...CONFIDENCE WAS LOW THAT ANY MEASURABLE PCPN WILL DEVELOP. THE BEST CHANCE FOR ANY PCPN WOULD BE IN UPSLOPE LOCATIONS DOWNWIND OF LAKE SUPERIOR LATE IN THE DAY. AS THE LOW LIFTS INTO MN AND THE 850 WARM FRONT OVER WI LIFTS THROUGH UPPER MI...A BAND OF 295K-305K ISENTROPIC LIFT WILL STRENGTHEN ENOUGH TO SUPPORT LIKELY RAIN CHANCES THROUGH UPPER MI BY SATURDAY MORNING. WITH MUCAPE VALUES TO AROUND 400 J/KG BY SATURDAY AFTERNOON SOME TSRA MAY BE POSSIBLE. SAT NIGHT...AS THE LOW LIFTS THROUGH MN TO NEAR CYQT THE FOCUS FOR STRONGER ISENTROPIC LIFT ALONG THE 850-700 MB FRONT WILL ALOS LIFT NORTH OF THE AREA. HOWEVER...SOME SHOWERS WILL STILL BE POSSIBLE IN THE WARM SECTOR AS WEAK SHORTWAVES ARE LIKELY TO MOVE THROUGH THE AREA. SUN...THE BEST CHANCE FOR WIDEPSREAD MODERATE TO OCNLY HEAVY RAIN WILL BE ALONG THE COLD FRONT AS THE LOW LIFT TOWARDS JAMES BAY AND MOISTURE TRANSPORT PUSHES PWAT VALUES TO 1.00-1.25 INCH...250-300 PCT OF NORMAL. MUCAPE VALUES TO AROUND 400 J/KG ALSO SUGGEST THAT ISOLD TSRA WILL REMAIN POSSIBLE. GIVEN THE HIGH AMPLITUDE PATTERN...THE SLOWER ECMWF WAS PREFERRED WITH THE TIMING OF THE FRONT COMPARED TO THE GFS. MON INTO TUE...A PERIOD OF LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY WNW TO NW FLOW IS EXPECTED AS CAA DROPS 850 MB TEMPS TO AROUND -12C. THE GEFS/GFS AND ECMWF WERE SIMILAR WITH A QUICK TRANSITION TO MORE ZONAL FLOW BY TUE NIGHT WHICH WOULD END LES POTENTIAL AND BRING MODERATING TEMPS CLOSER TO NORMAL BY WED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 547 AM EST THU NOV 8 2012 INCREASED MIXING AND DOWNSLOPE SW WINDS AT IWD AND SAW SHOULD HELP KEEP CEILINGS IN THE VFR RANGE THROUGH THE EVENING HOURS. WINDS WILL BE ON THE INCREASE...WITH GUSTS IN THE 18-22KT RANGE AT IWD AND SAW DURING THE EARLY AFTERNOON HOURS...JUST AHEAD OF THE NEARING COLD FRONT FROM THE WNW. ADDITIONAL MOISTURE WILL SLIP IN OVERNIGHT...AT OR BELOW 5KFT...BEHIND THE EXITING FRONTAL BOUNDARY AS WINDS SLOWLY TURN W AND THEN MAINLY OUT OF A N DIRECTION PRIOR TO DAYBREAK FRIDAY. WHILE LITTLE TO NO PRECIP IS EXPECTED WITH THE FRONT...FLIGHT CATEGORIES WILL LIKELY FALL INTO THE MVFR RANGE AT BOTH SAW AND IWD...WHILE REMAINING VFR AT CMX GIVEN THE LESS FAVORABLE WIND DIRECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST THU NOV 8 2012 THE RIDGE OF HIGH PRESSURE OVER LAKE MI AND LAKE HURON WILL CONTINUE TO PUSH E AS A LOW ACROSS NW MN MOVES TO JAMES BAY THIS AFTERNOON. THIS WILL ALLOW A TROUGH TO SWING ACROSS SLAKE SUPERIOR TONIGHT. THIS WILL ALLOW S-SE GUSTS OF 25-30KTS OVER THE E THIRD OF LS. A RIDGE WILL TEMPORARILY BUILD ACROSS LS BEHIND THE TROUGH ON FRIDAY...WITH FUNNELING NE WINDS ACROSS W LS GUSTING 20-30KTS WOUND NOT BE OUT OF THE QUESTION FRIDAY THROUGH SATURDAY. A FEW GALE FORCE GUSTS MAY NEED TO BE MENTIONED FAR W SATURDAY. A DEEPER LOW ACROSS THE CENTRAL PLAINS SATURDAY MORNING WILL CROSS LS LATE SATURDAY NIGHT...BEFORE MOVING OVER JAMES BAY LATE SUNDAY NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...KF SHORT TERM...KF LONG TERM...JLB AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MEDFORD OR
351 AM PST THU NOV 8 2012 .DISCUSSION...A SHORTWAVE TROUGH...REPRESENTING A SECONDARY PUSH OF COLD AIR...IS APPROACHING THE COAST THIS MORNING. CLOUD TOPS ARE COOLING...SUGGESTING A STRENGTHENING SHORTWAVE AND THE FIRST SIGNS OF PRECIPITATION ARE SHOWING UP ON RADAR RETURNS AT THE COAST. LATEST RAP MODEL DEPICTS A BAND OF SHOWERS PUSHING INTO THE COAST BY 8AM AND THEN MOVING INLAND TO JACKSON COUNTY BY 11AM. SNOW LEVELS ARE CURRENTLY ABOUT 3000 FEET JUST INLAND FROM THE COAST...AND SHOULD BE ABOUT 2000 FEET AS THE FIRST BAND OF SHOWERS MOVES IN. THE HEAVIEST SHOWERS THIS MORNING COULD IMPACT ROADWAYS LIKE INTERSTATE 5 AT SEXTON SUMMIT...AND PERHAPS HAYES HILL. THIS AFTERNOON WINTER WEATHER IMPACTS WILL SHIFT EASTWARD TO SISKIYOU SUMMIT WHERE ROAD TEMPERATURES SHOULD COOL AND ALLOW FOR SOME ACCUMULATION ON THE ROADWAYS. AFTER SUNSET...AS ROAD TEMPERATURES COOL AND SHOWERS CONTINUE...IMPACTS TO ROADWAYS ARE MORE LIKELY. A WINTER WEATHER ADVISORY AT WSWMFR HAS BEEN ISSUED FOR MUCH OF JOSEPHINE COUNTY ABOVE 1500 FEET AND THE SISKIYOUS AND CASCADES...TO INCLUDE I-5 AT SISKIYOU SUMMIT AND HWY 140 AT LAKE OF THE WOODS. EVEN THOUGH SNOW AMOUNTS ARE NOT EXPECTED TO RIVAL SIGNIFICANT MIDWINTER STORMS...ONLY AMOUNTING TO SEVERAL INCHES...THE SHARP TRANSITION TO LOW SNOW LEVELS AND THE EARLY SEASON NATURE OF THIS STORM WARRANTED A PRODUCT TO HIGHLIGHT POTENTIAL IMPACTS. THE ROGUE VALLEY HAS THE POTENTIAL OF SEEING SOME SNOWFLAKES TONIGHT...BUT SHOWERS ARE NOT EXPECTED TO BE HEAVY ENOUGH TO LOWER ROAD TEMPERATURES BELOW FREEZING...SO ANY SNOW SHOULD MELT QUICKLY ON ROADWAYS. CONFIDENCE ON THE SNOW POTENTIAL EAST OF THE CASCADES IS LOWER THAN THE REST OF THE AREA. THIS IS BECAUSE RECENT MODELS HAVE TRENDED UPWARD FROM LITTLE SNOW TO POTENTIALLY SEVERAL INCHES OF SNOW. THE MECHANISM APPEARS TO BE A DEFORMATION ZONE ALOFT AND STRONG LOW LEVEL CONVERGENCE. IN ANY CASE...HAVE BUMPED UP POPS SIGNIFICANTLY AND HAVE ISSUED A WINTER WEATHER ADVISORY...AGAIN AT WSWMFR...FOR MOST PLACES EAST OF THE CASCADES. THE GENERAL IDEA IS FOLKS COULD GO TO SLEEP TONIGHT WITH LITTLE TO NO SNOW ACCUMULATION AND WAKE UP TO A FEW INCHES OF SNOW AND SNOW COVERED ROADS. A GRADUAL DECREASE IN SHOWER ACTIVITY IS EXPECTED FRIDAY INTO SATURDAY...WITH DRY WEATHER AND WARMER TEMPERATURES EXPECTED ON SUNDAY. ANOTHER IMPULSE ON FRIDAY COULD GENERATE SIGNIFICANT SHOWERS WEST OF THE CASCADES AND HAVE BUMPED UP POPS FOR THAT AREA AND TIMEFRAME. WITH CONTINUED RELATIVELY LOW SNOW LEVELS...THIS WILL HAVE TO BE MONITORED. && .AVIATION...A MAJOR SHIFT IN THE WEATHER PATTERN IS EXPECTED TO IMPACT FLYING ACROSS THE FORECAST AREA TODAY AND TONIGHT. WIDESPREAD MVFR WITH LOCAL IFR AND TERRAIN OBSCURATIONS WILL OCCUR ACROSS THE WEST SIDE AS A COLD FRONT PUSHES INLAND EARLY THIS MORNING. WE`LL SEE A TRANSITION TO A MORE SHOWERY PATTERN BEHIND THE FRONT TODAY. SO, EXPECT A MIX OF VFR AND MVFR WITH ISOLATED IFR IN HEAVIER SNOW SHOWERS, BUT MOUNTAIN OBSCURATIONS WILL BECOME WIDESPREAD. WITH THE ARRIVAL OF VERY COLD AIR ALOFT, SOME SMALL HAIL/GRAUPEL MAY ACCOMPANY ANY OF THE HEAVIER SHOWERS AT LOWER ELEVATIONS, WHILE SNOW LEVELS FALL TO BETWEEN 2500 AND 3000 FEET BY THURSDAY EVENING. ISOLATED THUNDER ALSO CANNOT BE RULED OUT ALONG THE COAST. WEST SIDE SNOW LEVELS WILL DROP AS LOW AS 1500 FEET BY FRIDAY MORNING. EAST OF THE CASCADES, EXPECT MOSTLY VFR EARLY THIS MORNING, BUT AN AREA OF MVFR CIGS WITH -SHRA/-SHSN WILL EXTEND FROM EASTERN SISKIYOU COUNTY TO SOUTHERN LAKE AND MODOC COUNTIES BY LATE MORNING AND INTO THE AFTERNOON. MOUNTAIN OBSCURATION WILL BECOME PREVALENT BY THIS AFTERNOON. EAST SIDE SNOW LEVELS WILL BE AT VALLEY FLOORS TODAY AS COLDER AIR MOVES IN. LATER TODAY AND TONIGHT...EXPECT A MIX OF VFR AND MVFR BUT LOCAL IFR IN ANY HEAVIER SNOW SHOWERS. SPILDE/KEENE && .MFR WATCHES/WARNINGS/ADVISORIES... OR...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM PST FRIDAY FOR ORZ029>031. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 10 PM PST THIS EVENING FOR ORZ024. WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM PST FRIDAY FOR ORZ027-028. CA...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM PST FRIDAY FOR CAZ082>085. WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 4 AM PST FRIDAY FOR CAZ080. PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 1 PM THIS AFTERNOON TO 10 PM PST FRIDAY FOR PZZ350-356. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST FRIDAY FOR PZZ370-376. $$ SK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
917 AM MST THU NOV 8 2012 .UPDATE...SURGE HAS MOVED ACROSS DENVER AREA A FEW HOURS EARLIER THAN MODELS SUGGESTED. WITH SURFACE LOW OVER SOUTHEAST COLORADO PROGGED TO GRADUALLY STRENGTHEN...WOULD EXPECT WINDS TO BECOME EASTERLY THEN SOUTHEAST DURING THE AFTERNOON. WILL BE ADJUSTING WIND GRIDS AS NEEDED. ALSO...FAIRLY EXTENSIVE WAVE CLOUD DEVELOPED ACROSS THE FOOTHILLS AND PORTIONS OF THE URBAN CORRIDOR DURING THE EARLY MORNING. WRF SYNTHETIC SATELLITE IMAGERY SUGGESTS THE CLOUD DISSIPATING BY 20Z. BUT MORE MOISTURE IS UPSTREAM WHICH ALL THE MODELS SHOW MOVING ACROSS THE AREA BY THE EVENING. SO WILL ALSO NEED TO MAKE SOME ADJUSTMENTS TO THE CLOUD GRIDS. AIRMASS WILL BE COOLER BEHIND SURGE...CURRENT TEMPERATURE GRIDS SEEM REASONABLE AT THIS POINT. && .AVIATION...SURGE HAS MOVED ACROSS DIA A BIT SOONER THAN MODELS SUGGESTED...TAF HAS BEEN RECENTLY UPDATED. TIMING FOR APA AND BJC STILL LOOKING REASONABLE. WINDS STILL EXPECTED TO TREND TOWARD THE EAST AND SOUTHEAST DURING THE AFTERNOON...MAY HOLD ONTO A NORTHERLY COMPONENT UNTIL 20Z...PER HRRR SOLUTION. REST OF TAF TRENDS SEEM ON TRACK...THOUGH MAY BE A BIT MORE CIRRUS DURING THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 356 AM MST THU NOV 8 2012/ SHORT TERM...COLORADO WILL REMAIN ENTRENCHED UNDER THE BROAD UPPER LEVEL RIDGE THROUGH THIS AFTERNOON WITH MODERATE WESTERLY FLOW ALOFT. WATER VAPOR SATELLITE PICTURES SHOW SOME HIGH LEVEL TRAPPED UNDER THE RIDGE AXIS WHICH WILL MOVE ACROSS THE FORECAST AREA THROUGH THIS AFTERNOON. NOTHING MORE THAN HIGH CIRRUS IS EXPECTED FROM THE PASSING MOISTURE. AT THE SURFACE...A WEAK AND DRY COLD FRONT WILL MOVE ACROSS THE NORTHEAST PLAINS LATE IN THE MORNING AND STALL OVER THE PALMER DIVIDE BY MID-AFTERNOON. THIS WILL SWITCH THE WINDS TO THE NORTH AND THEN NORTHEAST AND EASTERLY THROUGH THE AFTERNOON HOURS. THE UPSLOPE COMPONENT TO THE WIND WILL HELP HOLD TEMPERATURES COOLER THAN YESTERDAY...BUT STILL SOME 10 TO 15 DEGREES WARMER THAN SEASONAL NORMALS. LOOKS LIKE TODAY AND FRIDAY WILL BE THE LAST COUPLE WARM DAYS OF AUTUMN FOR AWHILE AS BIG CHANGES ARE ANTICIPATED FOR THE WEEKEND. READ ON. LONG TERM...SW FLOW ALOFT WILL INCREASE AHEAD OF A STG UPPER LEVEL TROUGH ON FRI AS SFC LOW PRESSURE INTENSIFIES FM CNTRL WY INTO ERN CO. MOISTURE WILL GRADUALLY INCREASE THRU THE DAY IN THE MTNS WITH A SLIGHT CHANCE OF SHOWERS WEST OF THE DIVIDE. ACROSS NERN CO OUTSIDE OF SOME HIGH LVL CLOUDS IT WILL BE DRY. HIGHS OVER NERN CO WILL GENERALLY BE IN THE 60S ALTHOUGH AREAS ACROSS ERN ELBERT AND LINCOLN COUNTIES COULD RISE INTO THE LOWER 70S. FOR FRI NIGHT INTO SAT THE UPPER LEVEL TROUGH WILL MOVE INTO THE GREAT BASIN WITH SSW FLOW ALOFT. SHOULD SEE SNOW BECOME LIKELY FRI NIGHT INTO SAT AS SOME QG ASCENT COMBINES WITH DECENT LAPSE RATES. ZN 31 COULD DO WELL IN THIS SET UP SO MAY NEED AN ADVISORY FOR FRI NIGHT AND SAT. OTHERWISE SWLY FLOW IS NOT AS FAVORABLE IN MOST OTHER MTN AREAS. ACROSS NERN CO A CDFNT WILL MOVE INTO THE AREA BY 12Z SAT AND THEN MAY STALL OVER THE PALMER DIVIDE BY AFTN. AS A RESULT WILL SEE UPSLOPE FLOW DEVELOP FM DENVER NORTH TO THE WYOMING BORDER. COMBINATION OF DECENT LASPE RATES...AND POSITION OF UPPER LEVEL SHOULD ALLOW FOR INCREASING CHANCES FOR BANDED PCPN BY AFTN IN THE NRN FOOTHILLS AND NRN AREAS OF THE FRONT RANGE. SOUNDING DATA SHOWS WET BULB ZEROS DROPPING DOWN BLO 6000 FEET BY AFTN SO SHOULD SEE RAIN GRADUALLY CHANGE TO SNOW ALONG THE FRONT RANGE BY LATE AFTN. HIGHS ON SAT WILL VARY CONSIDERABLY BASED ON FNTL POSITION AS READINGS WILL ONLY BE IN THE LOWER TO MID 40S NORTH OF FNT WHILE SOUTH OF IT OVER LINCOLN COUNTY HIGHS COULD REACH THE LOWER 60S. BY SAT NIGHT INTO THE SUN THE MAIN UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA WITH THE FLOW ALOFT BECOMING MORE WLY. CROSS-SECTIONS STILL SHOW DECENT LAPSE RATES AND MOISTURE IN THE MTNS HOWEVER 700 MB FLOW IS RATHER WEAK BUT STILL SHOULD SEE SOME SNOW WITH AMOUNTS NEAR ADVISORY CRITERIA IN SOME AREAS THRU SUN MORNING. OVER NERN CO UPLSOPE FLOW WILL REMAIN IN PLACE SAT NIGHT AND AS MAIN PART OF TROUGH MOVES ACROSS WOULD THINK THERE WOULD BE A GOOD CHANCE OF SNOW FM THE FOOTHILLS ACROSS THE PLAINS WITH SNOW ENDING SUN MORNING. DEPENDING ON HOW THINGS SET UP COULD SEE FM 4 TO 8 INCHES IN THE FOOTHILLS WITH 2 TO 4 INCHES ACROSS NERN CO. HIGHS ON SUN WILL BE MUCH COLDER AS READINGS MAY NOT GET ABV 30 DEGREES OVER MOST OF NERN CO. FOR SUN NIGHT THE UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA WITH DRIER AIR EVENTUALLY SPREADING INTO NRN CO IN NWLY FLOW ALOFT. COULD STILL SEE A CHC OF -SHSN IN THE NRN MTNS DUE TO FAVORABLE OROGAPHIC FLOW. BY MON DRY NW FLOW ALOFT WILL BE IN PLACE WITH NO CHC OF PCPN. TEMPS WILL MODERATE SOME OVER NERN CO WITH READINGS IN THE LOWER TO MID 40S. BY TUE THE FLOW ALOFT WILL BECOME MORE WLY WITH THE GFS SHOWING QUITE A BIT OF MID AND HIGH LEVEL MOISTURE STREAMING ACROSS THE RGN SO COULD SEE QUITE A BIT OF CLOUD COVER BUT NO PCPN. HIGHS ON TUE COULD BE ALTERED BY CLOUD COVER OVER NERN CO SO CURRENT GUIDANCE TEMPS MAY BE TOO WRM. THUS WILL KEEP HIGHS IN THE 45 TO 50 DEGREE RANGE. FOR WED THE FLOW ALOFT WILL BECOME MORE SWLY AS ANOTHER UPPER LEVEL TROUGH DEVELOPS OVER THE WRN US. MID AND HIGH LEVEL MOISTURE EMBEDDED IN THIS FLOW MAY AFFECT THE AREA ONCE AGAIN WITH A SLIGHT CHANCE OF SHOWERS IN THE MTNS. OVER NERN CO A WK FNT MAY BACKDOOR INTO THE PLAINS DURING THE DAY WHICH MAY KEEP HIGHS SLIGHTLY BLO NORMAL. AVIATION...SKIES WILL BE CLEAR THIS MORNING BUT THEN INCREASING CIRRUS CLOUDS ARE EXPECTED BY AFTERNOON. NO CEILINGS ARE EXPECTED AS THE HIGH LEVEL MOISTURE SLOWLY INCREASES OVER THE STATE. WINDS THIS MORNING WILL BE OUT OF THE SOUTH...IN A TYPICAL DIURNAL DRAINAGE PATTERN. WINDS ARE EXPECTED TO SHIFT TO THE NORTH AND NORTHEAST BY LATE IN THE MORNING AS A WEAK SURGE OF COOLER AIR MOVES IN FROM THE NORTH. THROUGH THE AFTERNOON WINDS WILL SHIFT TO AN EASTERLY DIRECTION AS A SURFACE LOW BEGINS INTENSIFYING OVER SOUTHEAST COLORADO. ASIDE FROM A FEW WIND GUSTS TO 15 MPH WITH THE SHIFT TO NORTHERLY WINDS...SPEEDS SHOULD REMAIN AROUND 10 MPH AS THE WIND DIRECTION SHIFTS TO EASTERLY. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RPK AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
155 PM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * HI END MVFR CIGS PERSISTING TIL MID-LATE AFTERNOON. TRS //DISCUSSION...UPDATED 18Z... WESTERN EDGE OF STRATOCU DECK HAS BEEN CLEARING NORTHEASTWARD DURING THE MORNING AS SOUTHWESTERLY LOW LEVEL FLOW HAS BEEN VERY GRADUALLY BEEN INCREASING WITH THE SURFACE RIDGE AXIS SHIFTING FURTHER E ACROSS LOWER MI AND IN. THIS RETURN FLOW IS ADVECTING IN SLIGHTLY LOWER DEW POINTS BUT THEY WERE STILL HIGH ENOUGH FOR CONVECTIVE TEMPERATURE TO BE REACHED FOR A BIT OF DIURNAL BACK-FILLING. THIS HAS RESULTED IN A NET SLOWING OF THE PROGRESSION OF THE CLEARING. DURING THE MID TO LATE AFTERNOON MODEL FORECAST THERMAL AND MOISTURE PROFILES SUGGEST THAT THE TEMPERATURES AT THE BASE OF THE INVERSION THAT IS IN PLACE WILL WARM ENOUGH DUE TO BOTH ADVECTION AND SUBSIDENCE TO RAISE CONVECTIVE TEMPERATURES ENOUGH TO ALLOW TRAPPED LOW LEVEL MOISTURE TO START TO MIX OUT AND EXTINGUISH THE DIURNAL CLOUDS. CLEARING EXPECTED TO REACH IMMEDIATE CHI AREA AROUND 22Z. TONIGHT THERE SHOULD BE ENOUGH PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO HAVE MOVED TO THE MID-UPPER OH AND THE TN VALLEYS... AND LOW PRESSURE TO DEVELOP IN THE CENTRAL HIGH PLAINS TO KEEP ENOUGH OF A SOUTHWEST SURFACE FLOW ACROSS THE LOCAL AREA TO PREVENT ANY BR DEVELOPMENT. GRADIENT TO INCREASE DURING THE DAY FRI AS THE HIGH PLAINS LOW DEEPENS. WINDS JUST ABOVE THE BASE OF A LOW LEVEL INVERSION PROGGED TO INCREASE 20-25 KT BY 09.18Z BUT A DECK OF WARM AIR ADVECTION CLOUDS ALSO EXPECTED TO DEVELOP DURING THE MORNING SO SURFACE HEATING TO DEEPEN MIXED LAYER UP TO THESE WINDS WILL BE HINDERED AND SURFACE WINDS THROUGH MIDDAY EXPECTED TO REMAIN AOB 10 KT. TRS //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MODERATE CONFIDENCE IN STRATOCU CIGS SCATTERING OUT AROUND 22Z. * HIGH CONFIDENCE REST OF FORECASTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 136 PM CST HIGH PRESSURE WILL CONTINUE TO PUSH AWAY FROM THE REGION TONIGHT AS A WEAK COLD FRONT MOVING SOUTH DOWN THE LAKE LATE TONIGHT INTO FRIDAY BEFORE STALLING OUT OVER CENTRAL PORTIONS OF THE LAKE. THE FRONT WILL REMAIN NEARLY STATIONARY THROUGH SATURDAY MORNING WITH SOUTHERLY WINDS SOUTH OF THE FRONT AND A MORE EASTERLY FLOW TO THE NORTH. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL HIGH PLAINS FRIDAY INTO FRIDAY NIGHT AND THEN BEGIN DEEPENING AS IT LIFTS NORTHEAST TOWARD THE UPPER MISSISSIPPI VALLEY REGION SATURDAY. WRF-NAM AND WRF-NMM BOTH SUGGEST THAT A PERIOD OF EASTERLY GALES WILL DEVELOP OVER FAR NORTHERN PORTIONS OF THE LAKE SATURDAY MORNING INTO THE EARLY AFTERNOON IN RESPONSE TO FAIRLY STRONG PRESSURE FALLS OVER THE UPPER MS RIVER VALLEY IN ADVANCE OF THE DEEPENING LOW. DP/DROP FROM LAST 4 RUNS OF THE WRF-NAM SHOW THE FORECAST WINDS HAVE BEEN TRENDING STRONGER EACH OF THE LAST 4 RUNS LENDING A BIT MORE CONFIDENCE TO THE IDEA OF A PERIOD OF EAST GALES. IN ADDITION...THE EASTERLY DIRECTION WILL FAVOR SOME CHANNELING OF THE WINDS THROUGH THE MACKINAW STRAITS FROM LAKE HURON AND WITH BOUNDARY LAYER STILL PROGGED TO BE MODERATELY COLDER THAN LAKE TEMPS INSTABILITY SHOULD FAVOR SUFFICIENT MIXING. FORECAST SOUNDINGS FROM BUFKIT POINT LM1 DO NOT SHOW THE STRONG WINDS AS THE CHANNEL OF STRONGEST WINDS HAS CONSISTENTLY BEEN PROGGED TO REMAIN NORTH OF LM1. SOUTHERLY WINDS WILL BE FAIRLY STRONG OVER THE ENTIRE LAKE SATURDAY NIGHT INTO SUNDAY AS THE LOW TRACKS NORTHEAST TOWARD JAMES BAY...BUT WITH SOUTHERLY WINDS ADVECTING UNSEASONABLY TO NEAR RECORD WARM AIR NORTHWARD AM CONCERNED ABOUT THE STABILITY OF THE MARINE LAYER AND HOW EFFECTIVELY THE STRONGER WINDS ALOFT WILL BE AT BEING TRANSPORTED TO THE SURFACE. PLAN TO HOLD WINDS SAT NIGHT/SUNDAY JUST BELOW GALES FOR NOW GIVEN THE UNCERTAINTY AND JUST INCLUDE OCNL GALE FORCE GUSTS AND HOLD OFF ON ANY HEADLINES FOR THAT TIME PERIOD. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
136 PM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * HI END MVFR CIG PERSISTING INTO MID-LATE AFTERNOON. TRS //DISCUSSION...UPDATED 18Z... WESTERN EDGE OF STRATOCU DECK HAS BEEN CLEARING NORTHEASTWARD DURING THE MORNING AS SOUTHWESTERLY LOW LEVEL FLOW HAS BEEN VERY GRADUALLY BEEN INCREASING WITH THE SURFACE RIDGE AXIS SHIFTING FURTHER E ACROSS LOWER MI AND IN. THIS RETURN FLOW IS ADVECTING IN SLIGHTLY LOWER DEW POINTS BUT THEY WERE STILL HIGH ENOUGH FOR CONVECTIVE TEMPERATURE TO BE REACHED FOR A BIT OF DIURNAL BACK-FILLING. THIS HAS RESULTED IN A NET SLOWING OF THE PROGRESSION OF THE CLEARING. DURING THE MID TO LATE AFTERNOON MODEL FORECAST THERMAL AND MOISTURE PROFILES SUGGEST THAT THE TEMPERATURES AT THE BASE OF THE INVERSION THAT IS IN PLACE WILL WARM ENOUGH DUE TO BOTH ADVECTION AND SUBSIDENCE TO RAISE CONVECTIVE TEMPERATURES ENOUGH TO ALLOW TRAPPED LOW LEVEL MOISTURE TO START TO MIX OUT AND EXTINGUISH THE DIURNAL CLOUDS. CLEARING EXPECTED TO REACH IMMEDIATE CHI AREA AROUND 22Z. TONIGHT THERE SHOULD BE ENOUGH PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO HAVE MOVED TO THE MID-UPPER OH AND THE TN VALLEYS... AND LOW PRESSURE TO DEVELOP IN THE CENTRAL HIGH PLAINS TO KEEP ENOUGH OF A SOUTHWEST SURFACE FLOW ACROSS THE LOCAL AREA TO PREVENT ANY BR DEVELOPMENT. GRADIENT TO INCREASE DURING THE DAY FRI AS THE HIGH PLAINS LOW DEEPENS. WINDS JUST ABOVE THE BASE OF A LOW LEVEL INVERSION PROGGED TO INCREASE 20-25 KT BY 09.18Z BUT A DECK OF WARM AIR ADVECTION CLOUDS ALSO EXPECTED TO DEVELOP DURING THE MORNING SO SURFACE HEATING TO DEEPEN MIXED LAYER UP TO THESE WINDS WILL BE HINDERED AND SURFACE WINDS THROUGH MIDDAY EXPECTED TO REMAIN AOB 10 KT. TRS //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MODERATE CONFIDENCE IN STRATOCU CIGS SCATTERING OUT AROUND 22Z. * HIGH CONFIDENCE REST OF FORECASTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 136 PM CST HIGH PRESSURE WILL CONTINUE TO PUSH AWAY FROM THE REGION TONIGHT AS A WEAK COLD FRONT MOVING SOUTH DOWN THE LAKE LATE TONIGHT INTO FRIDAY BEFORE STALLING OUT OVER CENTRAL PORTIONS OF THE LAKE. THE FRONT WILL REMAIN NEARLY STATIONARY THROUGH SATURDAY MORNING WITH SOUTHERLY WINDS SOUTH OF THE FRONT AND A MORE EASTERLY FLOW TO THE NORTH. LOW PRESSURE WILL DEVELOP OVER THE CENTRAL HIGH PLAINS FRIDAY INTO FRIDAY NIGHT AND THEN BEGIN DEEPENING AS IT LIFTS NORTHEAST TOWARD THE UPPER MISSISSIPPI VALLEY REGION SATURDAY. WRF-NAM AND WRF-NMM BOTH SUGGEST THAT A PERIOD OF EASTERLY GALES WILL DEVELOP OVER FAR NORTHERN PORTIONS OF THE LAKE SATURDAY MORNING INTO THE EARLY AFTERNOON IN RESPONSE TO FAIRLY STRONG PRESSURE FALLS OVER THE UPPER MS RIVER VALLEY IN ADVANCE OF THE DEEPENING LOW. DP/DROP FROM LAST 4 RUNS OF THE WRF-NAM SHOW THE FORECAST WINDS HAVE BEEN TRENDING STRONGER EACH OF THE LAST 4 RUNS LENDING A BIT MORE CONFIDENCE TO THE IDEA OF A PERIOD OF EAST GALES. IN ADDITION...THE EASTERLY DIRECTION WILL FAVOR SOME CHANNELING OF THE WINDS THROUGH THE MACKINAW STRAITS FROM LAKE HURON AND WITH BOUNDARY LAYER STILL PROGGED TO BE MODERATELY COLDER THAN LAKE TEMPS INSTABILITY SHOULD FAVOR SUFFICIENT MIXING. FORECAST SOUNDINGS FROM BUFKIT POINT LM1 DO NOT SHOW THE STRONG WINDS AS THE CHANNEL OF STRONGEST WINDS HAS CONSISTENTLY BEEN PROGGED TO REMAIN NORTH OF LM1. SOUTHERLY WINDS WILL BE FAIRLY STRONG OVER THE ENTIRE LAKE SATURDAY NIGHT INTO SUNDAY AS THE LOW TRACKS NORTHEAST TOWARD JAMES BAY...BUT WITH SOUTHERLY WINDS ADVECTING UNSEASONABLY TO NEAR RECORD WARM AIR NORTHWARD AM CONCERNED ABOUT THE STABILITY OF THE MARINE LAYER AND HOW EFFECTIVELY THE STRONGER WINDS ALOFT WILL BE AT BEING TRANSPORTED TO THE SURFACE. PLAN TO HOLD WINDS SAT NIGHT/SUNDAY JUST BELOW GALES FOR NOW GIVEN THE UNCERTAINTY AND JUST INCLUDE OCNL GALE FORCE GUSTS AND HOLD OFF ON ANY HEADLINES FOR THAT TIME PERIOD. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WATCH...LMZ261-LMZ362...6 AM SATURDAY TO 3 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1147 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * HI END MVFR CIG PERSISTING INTO MID-LATE AFTERNOON. TRS //DISCUSSION...UPDATED 18Z... WESTERN EDGE OF STRATOCU DECK HAS BEEN CLEARING NORTHEASTWARD DURING THE MORNING AS SOUTHWESTERLY LOW LEVEL FLOW HAS BEEN VERY GRADUALLY BEEN INCREASING WITH THE SURFACE RIDGE AXIS SHIFTING FURTHER E ACROSS LOWER MI AND IN. THIS RETURN FLOW IS ADVECTING IN SLIGHTLY LOWER DEW POINTS BUT THEY WERE STILL HIGH ENOUGH FOR CONVECTIVE TEMPERATURE TO BE REACHED FOR A BIT OF DIURNAL BACK-FILLING. THIS HAS RESULTED IN A NET SLOWING OF THE PROGRESSION OF THE CLEARING. DURING THE MID TO LATE AFTERNOON MODEL FORECAST THERMAL AND MOISTURE PROFILES SUGGEST THAT THE TEMPERATURES AT THE BASE OF THE INVERSION THAT IS IN PLACE WILL WARM ENOUGH DUE TO BOTH ADVECTION AND SUBSIDENCE TO RAISE CONVECTIVE TEMPERATURES ENOUGH TO ALLOW TRAPPED LOW LEVEL MOISTURE TO START TO MIX OUT AND EXTINGUISH THE DIURNAL CLOUDS. CLEARING EXPECTED TO REACH IMMEDIATE CHI AREA AROUND 22Z. TONIGHT THERE SHOULD BE ENOUGH PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO HAVE MOVED TO THE MID-UPPER OH AND THE TN VALLEYS... AND LOW PRESSURE TO DEVELOP IN THE CENTRAL HIGH PLAINS TO KEEP ENOUGH OF A SOUTHWEST SURFACE FLOW ACROSS THE LOCAL AREA TO PREVENT ANY BR DEVELOPMENT. GRADIENT TO INCREASE DURING THE DAY FRI AS THE HIGH PLAINS LOW DEEPENS. WINDS JUST ABOVE THE BASE OF A LOW LEVEL INVERSION PROGGED TO INCREASE 20-25 KT BY 09.18Z BUT A DECK OF WARM AIR ADVECTION CLOUDS ALSO EXPECTED TO DEVELOP DURING THE MORNING SO SURFACE HEATING TO DEEPEN MIXED LAYER UP TO THESE WINDS WILL BE HINDERED AND SURFACE WINDS THROUGH MIDDAY EXPECTED TO REMAIN AOB 10 KT. TRS //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MODERATE CONFIDENCE IN STRATOCU CIGS SCATTERING OUT AROUND 22Z. * HIGH CONFIDENCE REST OF FORECASTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 315 AM CST A RIDGE OF HIGH PRESSURE OVER THE CENTRAL AND EASTERN GREAT LAKES WILL WILL KEEP RELATIVELY LIGHT WINDS OVER LAKE MICHIGAN THIS MORNING. AS THE HIGH SAGS SOUTHEASTWARD ACROSS THE OHIO VALLEY TODAY AND A WEAK TROUGH OF LOW PRESSURE MOVES INTO THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON...WINDS OVER THE LAKE WILL BECOME SOUTHWESTERLY AND STRENGTHEN. THE PRESSURE GRADIENT WILL BE STRONGEST OVER THE NORTHERN PORTIONS TO THE LAKE WITH WINDS INCREASING TO 15 TO 25 KT. WINDS OVER THE SOUTHERN PORTIONS OF THE LAKE WILL BE A BIT WEAKER...AROUND 10 TO 15 KT. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND DEEPEN AS IT TRACKS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL STRENGTHEN TO 30KT ACROSS THE LAKE...AND DURING THE PERIOD WHEN THE LOW IS DEEPENING OVER NRN WISCONSIN AND WESTERN LAKE SUPERIOR...THERE WILL BE A CHANCE FOR SOME 35KT GALE FORCE GUSTS SATURDAY NIGHT AND SUNDAY MORNING. AS THE LOW TRACKS NORTHEAST TO JAMES BAY SUNDAY NIGHT...IT WILL DRAG A STRONG COLD FRONT ACROSS LAKE MICHIGAN...TURNING WINDS WESTERLY TO NORTHWESTERLY. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 AM CST THU NOV 8 2012 .DISCUSSION... 240 AM CST THE FORECAST CONCERNS THIS MORNING ARE FIRST OFF THE LINGERING PESKY STRATUS AND TIMING ITS DEPARTURE AS WELL AS TO WHAT DEGREE OF IMPACT THIS WILL HAVE ON TEMPERATURES. THEN ATTENTION TURNS TO THE WARM-UP WHICH ENSUES IN EARNEST FRIDAY INTO THE WEEKEND. FINALLY THE WEATHER SYSTEM RESPONSIBLE FOR THE WARMTH WILL BRING WARM AIR ADVECTION CHANCES OF PRECIP FRIDAY NIGHT INTO EARLY SATURDAY...AND THEN A MUCH BETTER CHANCE WITH THIS SYSTEM WILL COME SUNDAY INTO SUNDAY NIGHT. THE OTHER FOOT WILL THEN DROP WITH STRONG COLD AIR ADVECTION ON MONDAY AND AN ATMOSPHERE PLENTY COOL ENOUGH FOR SNOW SHOWERS. THE SURFACE HIGH PRESSURE RIDGE EARLY THIS MORNING EXTENDS FROM THE MID-MISSISSIPPI VALLEY NORTHEAST THROUGH LOWER MI AND SOUTHEAST CANADA. AN AREA OF STRATUS CAUGHT WITHIN THE NULL FLOW HUNG AROUND ALL WED NIGHT OVER THE FORECAST AREA AND REMAINS THIS MORNING. BUT THIS IS BEGINNING TO BE ON THE MOVE AS THE RETURN WIND FLOW BEGINS IN THE CLOUD-BEARING LAYER. THE CLOUD DEPTH IS ABOUT 1500-2000 FT PER AMDAR SOUNDINGS...NORMALLY SHALLOW ENOUGH TO BE SCATTERED THROUGH WARMING AND MORE TURBULENT FLOW TODAY. BUT A FAIRLY STOUT INVERSION DOES EXIST ABOVE THIS AND MIXING DEPTHS WILL NOT REACH AS DEEP AS THE CLOUD BASES THIS MORNING. SO GETTING THE STRATUS OUT OF HERE LOOKS TO DEPEND MORE ON ADVECTION AND THAT WILL INCREASE FROM THE SOUTHWEST. THE RAP SOLUTIONS OF RH FIELDS SEEMS TO DEPICT A VERY LIKELY SCENARIO...OF THE OVERCAST NATURE OF THE CLOUDS HOLDING THIS MORNING AS THEY ADVECT NORTHEASTWARD...MEANING THE CHICAGO AREA BEING THE LAST TO SCATTER IN NORTHERN IL...LIKELY NOT UNTIL THE NOON HOUR OR MAYBE EVEN JUST AFTER. HAVE ACCORDINGLY KEPT TEMPERATURES SLOW TO CLIMB THIS MORNING FOLLOWED BY GREATER WARMING EARLY THIS AFTERNOON. WITH A GENERALLY WARM STARTING POINT IN ALMOST ALL PLACES BECAUSE OF THE CLOUDS...FORECAST TEMPERATURES ACTUALLY WERE INCHED UP 2-3 DEGREES IN PARTS OF THE WEST AND SOUTH. THE LOW TO MID 50S TODAY WILL BE RIGHT AT NORMAL...THOUGH THE WARMEST READINGS SINCE THE 1ST OF THE MONTH. UPPER LEVEL RIDGING WILL THEN MOVE OVER THE AREA TONIGHT INTO FRIDAY AS AMPLIFICATION IN THE PATTERN OCCURS UPSTREAM...WITH A TROUGH TAKING SHAPE ACROSS THE WESTERN CONUS. A LEAD SHORT WAVE...ACTUALLY SEEN THIS MORNING ON WATER VAPOR JUST OFFSHORE OF SAN DIEGO...WILL PROGRESS NORTHEAST AHEAD OF THE TROUGH AND LINE UP WELL WITH THE BIG PUSH OF 700-925MB WARM AIR ADVECTION ON FRIDAY NIGHT. MODELS ARE IN GOOD AGREEMENT ON THIS...WITH A DEVELOPING WARM FRONT AIDING IN ISENTROPIC ASCENT AND CONVERGENCE...ESPECIALLY JUST TO THE NORTH OF THE AREA. MAINTAIN THE CHANCE OF POPS ACROSS NORTHERN AREAS AS WELL AS THE CHANCE FOR THUNDER...WITH ELEVATED LAPSE RATES AND ASSOCIATED CONVECTIVE INDICES BECOMING MODEST WITHIN THE DIFFERENTIAL THERMAL ADVECTION. LOWER TROPOSPHERIC TEMPS TAKE A NOTEWORTHY CLIMB ON SATURDAY AS CYCLOGENESIS IN THE CENTRAL PLAINS AND AN ASSOCIATED STRONG LOW- LEVEL JET IN ADVANCE LOOK TO STEER THE THERMAL RIDGE DIRECTLY OVER THE AREA FROM THE SOUTHWEST. WHILE MORNING CLOUD COVER CONTINUES A POSSIBILITY...ALMOST ALL GUIDANCE IS IN GOOD AGREEMENT WITH A DRYING COLUMN AND NVA IN THE WAKE OF THE AFOREMENTIONED WAVE BY SATURDAY AFTERNOON...AND SOUTHERN AREAS MAY BE SUNNY ON SATURDAY FROM THE GET-GO. LOCAL RESEARCH FOR 925 MB TEMPS AT THE FORECAST OF +14C THIS TIME OF YEAR PROVIDE A MEDIAN HIGH OF 67 DEGREES IN CHICAGO. AGAIN WITH CLOUDS BEING A CONCERN THAT FAR NORTH...AM NOT GOING ANY HIGHER...BUT FOR SOUTHERN AREAS DO HAVE HIGHS AROUND 70. THE SREF MEMBERS SUPPORT THIS...WITH EVEN A FEW MEMBERS FROM THE 08.03 GUIDANCE IN THE LOWER 70S FOR PONTIAC. IF CURIOUS TO WHERE THIS STANDS FOR NOV 10TH...THE RECORD HIGH AT CMI IS 74 AND BMI IS 76. THE UPPER LONG WAVE TROUGH WILL PROGRESS POSITIVELY TILTED THROUGH EARLY SUNDAY...WHICH SHOULD KEEP HEIGHT FALLS AND THE HEART OF THE MOISTURE TONGUE...AND THUS THE BETTER CHANCES FOR RAIN IN THE WARM SECTOR...CONFINED TOWARD THE COLD FRONT ITSELF. GUIDANCE IS IN FAIR AGREEMENT WITH THE FRONTAL TIMING DURING THE DAY SUNDAY ENTERING WESTERN IL...AND THEN SOME DECENT DIFFERENCES IN SPEED WITH THE PASSAGE SHOW UP. BUT GUIDANCE AGREES ON DEEP MOISTURE AND STRONG MOISTURE TRANSPORT AHEAD AND ALONG THE BOUNDARY. PWATS ON THE GFS ARE FORECAST TO BE AROUND 1.4 INCHES...WHICH IS THE 99TH PERCENTILE FOR NOV CLIMO IN NORTHERN/CENTRAL IL. SO HAVE A SLOW INCREASE IN POPS INTO EARLY SUNDAY AND THEN CATEGORICAL POPS SHIFTING EAST ACROSS THE AREA THROUGH SUNDAY NIGHT. COULD SEE SOME LOCALLY HEAVIER RAINFALL IN PLACES...BUT GENERAL DRYNESS THIS AUTUMN LOOKS TO PRECLUDE ANY MAJOR ISSUES WITH THAT...THOUGH SOMETHING TO KEEP MONITOR ON. ISOLATED TO SCATTERED THUNDER WITHIN THE MOIST TONGUE SUNDAY AFTERNOON AND EVE SEEM LIKE A GOOD BET BY NOVEMBER STANDARDS. TEMPERATURES LOOK TO COOL SIGNIFICANTLY AND POTENTIALLY VERY QUICKLY BEHIND THE FRONT LATE SUNDAY NIGHT AND/OR INTO MONDAY. TEMPERATURES ON MONDAY AFTERNOON ALREADY LOOK TO BE IN THE BALLPARK OF 30 DEGREES COOLER THAN ON SUNDAY AFTERNOON. DEPENDING ON HOW THE UPPER LOW EVOLVES...ANY FORCING FOR POST-FRONTAL PRECIP/SHOWERS WOULD VERY LIKELY CHANGE TO SNOW IF CONTINUING INTO MONDAY. THIS WOULD SEEM TO BE MORE SHOWERY WITH THE UPPER LOW BEING THE MAIN PLAYER AT THAT POINT. HIGHS ON TUE LOOK TO REMAIN IN THE 30S IN PLACES WITH FORECAST 850 MB TEMPERATURES IN THE -8C TO -10C RANGE. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * IMPROVEMENT OF MVFR CIGS TO VFR LATE MORNING-EARLY AFTERNOON. TRS //DISCUSSION...UPDATED 14Z... CONDITIONS AT ORD AND MDW SHOWED LITTLE OR NO CHANGE OVER LAST COUPLE HRS. LOCATIONS ACROSS N CENTRAL IL INCLUDING DKB...RPJ AND VYS HAVE HI END MVFR CIGS BUT P6SM VSBYS AS GRADUALLY INCREASING SW LLVL FLOW HAS BEEN ADVECTING IN SOMEWHAT LOWER DWPTS. HOWEVER...TO SW-SSW OF ORD AND MDW DWPTS STILL IN UPR 30S-LWR 40S WITH MVFR CIGS AND VSBYS AT LOT...C09...PNT...BMI AND AAA SO BELIEVE WILL TAKE A COUPLE HRS BEFORE WE SEE IMPROVEMENT VFR CIGS AND VSBYS. TRS PREVIOUS DISCUSSION...UPDATED 12Z... MAIN CONCERN FOR EARLY THIS MORNING WILL FOCUS ON CIGS/VIS. LATEST SATELLITE IMAGERY SHOWS THAT THE PERSISTENT AREA OF ST OVER IL/WI IS MOVING TO THE EAST...WITH THE WESTERN EDGE CROSSING THE MISSISSIPPI RIVER INTO NWRN IL. THE TREND FOR THE CLOUD COVER SHOULD BE TO THIN THROUGH THE MORNING AS THE SFC RIDGE AXIS MOVES EWD ACROSS THE REGION. THE AREAS OF 2-4SM BR SHOULD PERSIST FOR A COUPLE HOURS AFTER SUNRISE AS WINDS REMAIN LGT/VRBL...BUT SOME WARMING COMBINED WITH THINNING OF THE ST LAYER SHOULD ALLOW VIS TO IMPROVE TO VFR. SINCE THE ST LAYER HAS REMAINED THICK ENOUGH TO SUPPRESS RADIATIVE COOLING...DO NOT EXPECT VISIBILITY TO DROP ANY LOWER THAN THAT WHICH IS OCCURRING AT ISSUANCE TIME. CONDITIONS SHOULD BE RATHER QUIET AT THE TERMINALS THROUGH THE DAY WITH LIGHT WINDS PERSISTING THROUGH THE REMAINDER OF THE MORNING HOURS. WINDS SHOULD STRENGTHEN BY LATE MORNING/EARLY AFTERNOON AND BECOME MORE SLY-SWLY AS A TROUGH OF LOW PRESSURE MOVES EWD ACROSS THE PLAINS. EXPECT THAT WINDS SHOULD INCREASE TO ARND 10KT...WITH SOME OCNL HIGHER GUSTS THROUGH THE AFTERNOON. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MODERATE CONFIDENCE IN CIGS IMPROVE TO VFR 19-20Z. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. TRS //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT...CHANCE SHRA/SLIGHT CHANCE TSRA. SATURDAY...SLIGHT CHANCE SHRA EARLY. CHANCE SHRA/SLIGHT CHANCE TSRA LATE. SUNDAY...LIKELY SHRA WITH CHC TSRA. MVFR/IFR POSSIBLE. MONDAY...RAIN LIKELY EARLY...CHANGING TO SNOW IN THE AFTERNOON. MVFR/IFR LIKELY. TUESDAY...VFR. WX NIL. WEDNESDAY...VFR. WX NIL. KREIN && .MARINE... 315 AM CST A RIDGE OF HIGH PRESSURE OVER THE CENTRAL AND EASTERN GREAT LAKES WILL WILL KEEP RELATIVELY LIGHT WINDS OVER LAKE MICHIGAN THIS MORNING. AS THE HIGH SAGS SOUTHEASTWARD ACROSS THE OHIO VALLEY TODAY AND A WEAK TROUGH OF LOW PRESSURE MOVES INTO THE UPPER MISSISSIPPI VALLEY THIS AFTERNOON...WINDS OVER THE LAKE WILL BECOME SOUTHWESTERLY AND STRENGTHEN. THE PRESSURE GRADIENT WILL BE STRONGEST OVER THE NORTHERN PORTIONS TO THE LAKE WITH WINDS INCREASING TO 15 TO 25 KT. WINDS OVER THE SOUTHERN PORTIONS OF THE LAKE WILL BE A BIT WEAKER...AROUND 10 TO 15 KT. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL PLAINS FRIDAY NIGHT AND DEEPEN AS IT TRACKS INTO THE UPPER MISSISSIPPI VALLEY SATURDAY NIGHT AND SUNDAY MORNING. WINDS WILL STRENGTHEN TO 30KT ACROSS THE LAKE...AND DURING THE PERIOD WHEN THE LOW IS DEEPENING OVER NRN WISCONSIN AND WESTERN LAKE SUPERIOR...THERE WILL BE A CHANCE FOR SOME 35KT GALE FORCE GUSTS SATURDAY NIGHT AND SUNDAY MORNING. AS THE LOW TRACKS NORTHEAST TO JAMES BAY SUNDAY NIGHT...IT WILL DRAG A STRONG COLD FRONT ACROSS LAKE MICHIGAN...TURNING WINDS WESTERLY TO NORTHWESTERLY. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1201 PM MST THU NOV 8 2012 .UPDATE... ISSUED AT 1152 AM MST THU NOV 8 2012 JUST COMPLETED ANOTHER UPDATE. MAIN CHANGE WAS TO LOWER MAXES IN THE SOUTHWEST AND WEST CENTRAL PORTION OF THE AREA. COLD AIR ADVECTION HAS BEEN DECENT AND TEMPERATURES ARE STRUGGLING A LITTLE TO RISE. LATEST RUC AND NAM APPEAR TO BE CAPTURING THIS WELL AND ARE SIMILAR. SO ADJUSTED THE MAXES DOWN MOSTLY AS STATED ABOVE WITH SLIGHTER ADJUSTMENTS FURTHER NORTH AND EAST PER THAT GUIDANCE AND LATEST TRENDS. ALSO ADJUSTED DEWPOINTS DOWN FOR TOMORROW. UPDATE ISSUED AT 925 AM MST THU NOV 8 2012 JUST COMPLETED AN UPDATE. WINDS HAVE INCREASED AND BECOME GUSTY AS BOUNDARY IS BEGINNING TO MOVE THROUGH. UPSTREAM OBSERVATIONS AND AREA VWPS INDICATE AT LEAST 15 TO 25 MPH. RUC AND NAM BUFKIT WOULD INDICATE THESE WINDS WILL DROP OFF WITHIN A COUPLE OF HOURS AS THEY START SHIFTING TOWARD THE EAST. PER SATELLITE AND LATEST NAM EXPECT SOME INCREASE IN CLOUD COVER THIS AFTERNOON INTO THIS EVENING SO FOLLOWED THAT TREND IN THE GRIDS. ALSO ADJUSTED DEWPOINTS PER LATEST OBSERVATIONS AND DEWPOINTS. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 325 AM MST THU NOV 8 2012 WARM AND DRY CONDITIONS WILL COME TO AN END THIS WEEKEND. ABOVE AVERAGE TEMPERATURES WILL CONTINUE THROUGH FRIDAY. THE UPPER RIDGE AXIS MOVES EAST AHEAD OF THE APPROACHING TROUGH OVER THE WESTERN UNITED STATES WITH THE UPPER FLOW TURNING SOUTHWEST OVER THE REGION AS THE SURFACE LOW PRESSURE CENTER DEEPENS OVER SOUTHEAST WYOMING AND NORTHEAST COLORADO THROUGH FRIDAY EVENING. THE INITIAL VORT MAX LIFTS OUT OF THE BASE OF THE UPPER TROUGH DURING THE DAY ON SATURDAY WITH THE COLD FRONT MOVING ACROSS THE FORECAST AREA. THERE WILL BE AN INCREASING CHANCE OF LIGHT RAIN SPREADING ACROSS THE FORECAST AREA FOLLOWING THE COLD FRONT ON SATURDAY AFTERNOON. SATURDAY NIGHT...AS TEMPERATURES DROP...LIGHT RAIN WILL BE MIXING WITH AND CHANGING TO LIGHT SNOW ACROSS THE REGION. TEMPERATURES SATURDAY NIGHT WILL BE 15-20 DEGREES COOLER THAN FRIDAY NIGHT. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1149 PM MST WED NOV 7 2012 COLD HIGH PRESSURE WILL SETTLE OVER THE REGION SUNDAY. LIGHT SNOW OR FLURRIES MAY LINGER INTO THE DAY WITH THE UPPER TROUGH AXIS OVERHEAD...WITH LITTLE OR NO ADDITIONAL ACCUMULATION. TEMPERATURES ARE EXPECTED TO FALL INTO THE TEENS SUNDAY NIGHT WITH LIGHT WINDS AND CLEARING SKIES. THE REST OF THE PERIOD WILL BE DRY WITH TEMPERATURES BELOW NORMAL AS A SHORTWAVE RIDGE MOVES ACROSS THE PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1046 AM MST THU NOV 8 2012 VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU THE TAF PERIOD AT BOTH MCK AND GLD. A WEAK COLD FRONT PUSHED SOUTH THROUGH BOTH TERMINALS THIS MORNING...INCREASING WINDS AS BOUNDARY LAYER MIXING OCCURED. WINDS WILL GRADUALLY TURN TO THE EAST OVERNIGHT WITH A FEW HIGH CLOUDS AHEAD OF A DEEP UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHWEST CONUS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...024 AVIATION...JJM/BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1047 AM MST THU NOV 8 2012 .UPDATE... ISSUED AT 925 AM MST THU NOV 8 2012 JUST COMPLETED AN UPDATE. WINDS HAVE INCREASED AND BECOME GUSTY AS BOUNDARY IS BEGINNING TO MOVE THROUGH. UPSTREAM OBSERVATIONS AND AREA VWPS INDICATE AT LEAST 15 TO 25 MPH. RUC AND NAM BUFKIT WOULD INDICATE THESE WINDS WILL DROP OFF WITHIN A COUPLE OF HOURS AS THEY START SHIFTING TOWARD THE EAST. PER SATELLITE AND LATEST NAM EXPECT SOME INCREASE IN CLOUD COVER THIS AFTERNOON INTO THIS EVENING SO FOLLOWED THAT TREND IN THE GRIDS. ALSO ADJUSTED DEWPOINTS PER LATEST OBSERVATIONS AND DEWPOINTS. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 325 AM MST THU NOV 8 2012 WARM AND DRY CONDITIONS WILL COME TO AN END THIS WEEKEND. ABOVE AVERAGE TEMPERATURES WILL CONTINUE THROUGH FRIDAY. THE UPPER RIDGE AXIS MOVES EAST AHEAD OF THE APPROACHING TROUGH OVER THE WESTERN UNITED STATES WITH THE UPPER FLOW TURNING SOUTHWEST OVER THE REGION AS THE SURFACE LOW PRESSURE CENTER DEEPENS OVER SOUTHEAST WYOMING AND NORTHEAST COLORADO THROUGH FRIDAY EVENING. THE INITIAL VORT MAX LIFTS OUT OF THE BASE OF THE UPPER TROUGH DURING THE DAY ON SATURDAY WITH THE COLD FRONT MOVING ACROSS THE FORECAST AREA. THERE WILL BE AN INCREASING CHANCE OF LIGHT RAIN SPREADING ACROSS THE FORECAST AREA FOLLOWING THE COLD FRONT ON SATURDAY AFTERNOON. SATURDAY NIGHT...AS TEMPERATURES DROP...LIGHT RAIN WILL BE MIXING WITH AND CHANGING TO LIGHT SNOW ACROSS THE REGION. TEMPERATURES SATURDAY NIGHT WILL BE 15-20 DEGREES COOLER THAN FRIDAY NIGHT. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1149 PM MST WED NOV 7 2012 COLD HIGH PRESSURE WILL SETTLE OVER THE REGION SUNDAY. LIGHT SNOW OR FLURRIES MAY LINGER INTO THE DAY WITH THE UPPER TROUGH AXIS OVERHEAD...WITH LITTLE OR NO ADDITIONAL ACCUMULATION. TEMPERATURES ARE EXPECTED TO FALL INTO THE TEENS SUNDAY NIGHT WITH LIGHT WINDS AND CLEARING SKIES. THE REST OF THE PERIOD WILL BE DRY WITH TEMPERATURES BELOW NORMAL AS A SHORTWAVE RIDGE MOVES ACROSS THE PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1046 AM MST THU NOV 8 2012 VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU THE TAF PERIOD AT BOTH MCK AND GLD. A WEAK COLD FRONT PUSHED SOUTH THROUGH BOTH TERMINALS THIS MORNING...INCREASING WINDS AS BOUNDARY LAYER MIXING OCCURED. WINDS WILL GRADUALLY TURN TO THE EAST OVERNIGHT WITH A FEW HIGH CLOUDS AHEAD OF A DEEP UPPER LEVEL TROUGH MOVING THROUGH THE SOUTHWEST CONUS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...024 AVIATION...JJM/BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1139 AM CST THU NOV 8 2012 .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU VFR CONDITIONS EXPECTED TO PREVAIL THRU THE FORECAST VALID PERIOD. DIURNALLY GUSTY SOUTHERLY FLOW WILL CONTINUE ACROSS THE AREA WITH ONLY AN INCREASE IN HIGH CLOUDS EXPECTED INTO EARLY FRIDAY. THE MAIN CHALLENGE TONIGHT WILL BE THE POSITION OF THE SURFACE FRONTAL BOUNDARY WHICH WILL BECOME QUASI-STATIONARY ACROSS NORTH CENTRAL KANSAS. THIS WILL IMPACT PREVAILING WIND DIRECTION AT KRSL WITH BACKING TO AN EASTERLY COMPONENT TONIGHT...BEFORE VEERING MORE SOUTHERLY AGAIN BY LATE FRIDAY MORNING. THE NOCTURNAL LOW LEVEL JET LOOKS TO BE STRONGEST ACROSS OKLAHOMA INTO SOUTHEAST KANSAS INTO EARLY FRIDAY MORNING...AND HAVE INCLUDED LLWS AT KCNU WHERE SURFACE WINDS ARE EXPECTED TO DECOUPLE OVERNIGHT. KED && .PREV DISCUSSION... /ISSUED 525 AM CST THU NOV 8 2012/ AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION FORECAST CONCERN IS THE APPROACH OF THE SURFACE FRONT FROM THE WEST AT KRSL/KSLN. SOUTHERLY FLOW WILL PERSIST ACROSS THE AREA FOR MUCH OF THE TERMINALS. AFTERNOON WINDS ARE EXPECTED TO BE GUSTY WITH 15-20 KTS SUSTAINED AND GUSTS UPWARDS TO 30KTS. HOWEVER...AT KRSL AND KSLN THE SURFACE LOW WILL APPROACH AND THE BOUNDARY WILL BE IN THE AREA...THIS HAS ALREADY CAUSED WINDS AT KRSL TO DECREASE AS OF 11Z. THINK WINDS WILL BE WEAK...BUT SOUTHERLY AT KRSL THROUGH THE AFTERNOON...BUT AS THE EVENING APPROACHES THE WINDS WILL BE COME VARIABLE. SIMILAR THING EXPECTED AT KSLN...BUT TIMING IS DELAYED UNTIL LATER THIS AFTERNOON AND AFTER DARK. DESPITE THE WIND DIRECTION ISSUES AT KRSL/KSLN VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST AT ALL TERMINALS. BILLINGS PREV DISCUSSION... /ISSUED 323 AM CST THU NOV 8 2012/ DISCUSSION... TODAY-FRI: MAIN FOCUS IS ON MOISTURE RETURN AHEAD OF APPROACHING FRONT. GFS STILL APPEARS TO BE RUNNING MOIST...AND ALTHOUGH NAM EVOLUTION LOOKS GOOD...ITS ALREADY TOO FAST GIVEN OBSERVED SURFACE DEW POINTS ACROSS TX. HAVE TRENDED CLOSER TO RUC THIS MORNING AND THEN NAM/EC BLEND INTO FRI. GUSTY SOUTH WINDS ARE EXPECTED AS SURFACE PRESSURE GRADIENT INCREASES. COMBO OF POTENTIAL LOW CLOUDS AND INCREASING CIRRUS WILL MAKE BOTH MINIMUM/MAXIMUM TEMPERATURES TRICKY THIS PERIOD. EXPECT WINDS TO KEEP TEMPERATURES UP TONIGHT. BETTER CHANCE OF CLOUDS ON FRI MAY LIMIT WARMUP EAST OF I-35...WITH BIG WARMUP POSSIBLE ROUGHLY WEST OF HIGHWAY 14 WITH LOWER DEW POINTS AND MORE WEST/DOWNSLOPE WIND COMPONENT. SAT-SUN: OUTSIDE CHANCE THAT PRECIPITATION COULD BREAK OUT IN THETA-E ADVECTION ACROSS NORTHWEST SECTIONS OF FORECAST AREA SAT AFTERNOON...BUT CHANCES SHOULD RAMP UP SAT NIGHT-SUN AS FRONT MOVES THROUGH. NOW APPEARS THAT PRECIPITATION WOULD LIKELY END BEFORE FREEZING TEMPERATURES ARRIVE IN CENTRAL KS AND HAVE DROPPED MENTION OF SNOW AROUND DAYBREAK SUN FOR NOW. BY SUN MOST OF PRECIPITATION WILL BE EAST OF I-35...BUT TIMING IS A BIT QUESTIONABLE WITH FAIR AMOUNT DISCREPANCIES BETWEEN MODELS. PRECIPITATION MIGHT LINGER IN FAR SOUTHEAST SECTIONS INTO SUN NIGHT...BUT SUSPECT WOULD LIKELY BE LIMITED IN TIME AND SPACE. MUCH COLDER AIR WILL BE MOVING INTO THE AREA BEHIND THE FRONT. MON-WED: DRY CONDITION LIKELY THIS PERIOD. WITH BOTH GFS/ECMWF SHOWING UPPER FLOW BECOMING INCREASINGLY ZONAL THROUGH THIS PERIOD...EXPECT FAIRLY RAPID RECOVERY IN TEMPERATURES. HAVE NUDGED UP INITIALIZATION TEMPERATURES...ESPECIALLY ON WED FOR THIS. POTENTIAL IS EVEN WARMER. HOWEVER BOTH GFS/ECMWF SUGGEST THERE COULD BE FAIR AMOUNT OF CIRRUS IN THE AREA WITH THE LEFT FRONT QUADRANT OF APPROACHING 300MB SPEED MAXIMUM AND RELATIVELY LOW SUN ANGLE. -HOWERTON AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU A RIDGE OF HIGH PRESSURE ALOFT WILL RESULT IN TRANQUIL WEATHER ACROSS THE CENTRAL AND SOUTHERN PLAINS WHILE A TROUGH OF LOW PRESSURE AT THE SURFACE REMAINS ANCHORED OVER THE SOUTHERN HIGH PLAINS. THIS WILL RESULT IN INCREASING SOUTHERLY WINDS THROUGH THE DAY ON THURSDAY WITH GUSTS TO AROUND 30 KNOTS ANTICIPATED. MWM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 73 56 77 62 / 0 0 0 10 HUTCHINSON 72 55 78 59 / 0 0 0 10 NEWTON 70 56 76 59 / 0 0 0 10 ELDORADO 73 59 75 61 / 0 0 10 10 WINFIELD-KWLD 73 61 76 63 / 0 0 0 10 RUSSELL 66 45 81 57 / 0 0 0 10 GREAT BEND 70 45 82 58 / 0 0 0 10 SALINA 72 52 80 60 / 0 0 0 10 MCPHERSON 72 54 78 59 / 0 0 0 10 COFFEYVILLE 73 58 76 64 / 0 0 10 10 CHANUTE 71 56 75 60 / 0 0 10 10 IOLA 69 55 75 61 / 0 0 10 10 PARSONS-KPPF 72 60 76 62 / 0 0 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
932 AM MST THU NOV 8 2012 .UPDATE... ISSUED AT 925 AM MST THU NOV 8 2012 JUST COMPLETED AN UPDATE. WINDS HAVE INCREASED AND BECOME GUSTY AS BOUNDARY IS BEGINNING TO MOVE THROUGH. UPSTREAM OBSERVATIONS AND AREA VWPS INDICATE AT LEAST 15 TO 25 MPH. RUC AND NAM BUFKIT WOULD INDICATE THESE WINDS WILL DROP OFF WITHIN A COUPLE OF HOURS AS THEY START SHIFTING TOWARD THE EAST. PER SATELLITE AND LATEST NAM EXPECT SOME INCREASE IN CLOUD COVER THIS AFTERNOON INTO THIS EVENING SO FOLLOWED THAT TREND IN THE GRIDS. ALSO ADJUSTED DEWPOINTS PER LATEST OBSERVATIONS AND DEWPOINTS. && .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 325 AM MST THU NOV 8 2012 WARM AND DRY CONDITIONS WILL COME TO AN END THIS WEEKEND. ABOVE AVERAGE TEMPERATURES WILL CONTINUE THROUGH FRIDAY. THE UPPER RIDGE AXIS MOVES EAST AHEAD OF THE APPROACHING TROUGH OVER THE WESTERN UNITED STATES WITH THE UPPER FLOW TURNING SOUTHWEST OVER THE REGION AS THE SURFACE LOW PRESSURE CENTER DEEPENS OVER SOUTHEAST WYOMING AND NORTHEAST COLORADO THROUGH FRIDAY EVENING. THE INITIAL VORT MAX LIFTS OUT OF THE BASE OF THE UPPER TROUGH DURING THE DAY ON SATURDAY WITH THE COLD FRONT MOVING ACROSS THE FORECAST AREA. THERE WILL BE AN INCREASING CHANCE OF LIGHT RAIN SPREADING ACROSS THE FORECAST AREA FOLLOWING THE COLD FRONT ON SATURDAY AFTERNOON. SATURDAY NIGHT...AS TEMPERATURES DROP...LIGHT RAIN WILL BE MIXING WITH AND CHANGING TO LIGHT SNOW ACROSS THE REGION. TEMPERATURES SATURDAY NIGHT WILL BE 15-20 DEGREES COOLER THAN FRIDAY NIGHT. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1149 PM MST WED NOV 7 2012 COLD HIGH PRESSURE WILL SETTLE OVER THE REGION SUNDAY. LIGHT SNOW OR FLURRIES MAY LINGER INTO THE DAY WITH THE UPPER TROUGH AXIS OVERHEAD...WITH LITTLE OR NO ADDITIONAL ACCUMULATION. TEMPERATURES ARE EXPECTED TO FALL INTO THE TEENS SUNDAY NIGHT WITH LIGHT WINDS AND CLEARING SKIES. THE REST OF THE PERIOD WILL BE DRY WITH TEMPERATURES BELOW NORMAL AS A SHORTWAVE RIDGE MOVES ACROSS THE PLAINS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 406 AM MST THU NOV 8 2012 VFR CONDITIONS WITH A FEW HIGH CLOUDS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH GLD AND MCK. LIGHT NORTH WINDS WILL INCREASE DURING THE AFTERNOON AND THEN DIMINISH AND TURN SOUTHEASTERLY OVERNIGHT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...LOCKHART LONG TERM...024 AVIATION...LOCKHART
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1247 PM EST THU NOV 8 2012 .UPDATE... ISSUED AT 1240 PM EST THU NOV 8 2012 PRIMARY CHANGE TO THE FORECAST THIS HOUR WILL BE TO SPEED THE CLEARING TREND...AS INITIAL SHOWER/SPRINKLE BAND ASSOCIATED WITH I295K LIFT PUSHES EAST OF THE REGION WITH AREA BREAKING INTO "WARM SECTOR" SOUTHEAST OF LOW PRESSURE OVER WESTERN ONTARIO. THIS MAY ALLOW TEMPS TO REACH A DEGREE OR SO ABOVE PREVIOUSLY FORECASTED HIGHS...BUT MID 40S SHOULD STILL WORK FOR MOST LOCATIONS. UPDATE ISSUED AT 951 AM EST THU NOV 8 2012 LIGHT WARM ADVECTION /LIFT ON 295K SURFACE/ PRECIPITATION CONTINUES TO PUSH EAST THIS MORNING. MORNING INL/GRB/APX SOUNDING CONTINUES TO SHOW A REMNANT DRY WEDGE CENTERED AT H8...WHICH SUGGESTS THAT ANY OF THE RETURNS SEEN ON THE MQT 88D ARE LIKELY NO MORE THAN SPRINKLES. BEST ISENTROPIC ASCENT WILL CONTINUE TO SHIFT EAST AS THE DAY GOES ON...SO EXPECT ANY SPRINKLES TO GIVE WAY TO A DRY AFTERNOON. WITH THE BEST MOISTURE SHIFTING EAST AS THE DAY GOES ON...AND LOOKING AT UPSTREAM OBS OVER NORTHEAST MINNESOTA...SKIES WILL GRADUALLY IMPROVE /IWD ALREADY CLEARING AT THIS HOUR/...WITH PARTLY SUNNY SKIES OVERTAKING MOST OF THE CWA DURING THE AFTERNOON. CLOUDS WILL BE MOST STUBBORN OVER FAR EASTERN AREAS WITH MOIST PLUME OFF OF LAKE MICHIGAN POTENTIALLY IMPACTING MY FAR EASTERN ZONES THROUGH THE DAY GIVEN SOUTHWESTERLY LLEVEL FLOW. GOING FORECAST HAD THESE TRENDS WELL-HANDLED WITH ONLY MINOR TWEAKS TO POP/SKY TIMING. TEMPERATURES IN THE MID 40S EAST /MORE CLOUDS/ TO AROUND 50 WEST GIVEN T92S WARMING TO +2-4C IN THE AFOREMENTIONED WARM ADVECTION REGIME. UPDATE ISSUED AT 654 AM EST THU NOV 8 2012 SOME OF THE SHORTER SCALE FCST MODELS ARE HAVING A BETTER TIME HANDLING THE CURRENT SHOWER ACTIVITY OVER FAR W UPPER MI. UPDATED THE FCST /POPS/WX/QPF...WITH ASSISTANCE OF THE RUC GUIDANCE WHICH && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EST THU NOV 8 2012 ALTHOUGH MUCH OF THE ENERGY WITH THE WEAK SHORTWAVE IS CROSSING TO OUR NORTH...INCREASED MOISTURE AHEAD OF THE NEXT SFC LOW OVER THE DAKOTAS HAS ALLOWED FOR A BROKEN LINE OF SHOWERS TO DEVELOP. AS OF 09Z NO CLOUD TO GROUND LIGHTNING HAS BEEN FOUND WITH THIS SYSTEM. WHILE TEMPERATURES ALOFT WOULD SUPPORT RAIN SHOWERS /850MB TEMPS OF 0-3C OVER N WI EARLY THIS MORNING/...POCKETS OF COOLER AIR NEAR THE SFC COULD RESULT IN LIGHT FREEZING RAIN. AT6 09Z THE ONLY LOCATIONS SHOWING UP ON THE MESONET BELOW FREEZING WERE PEAVY FALLS AND RANDVILLE...JUST NW OF IRON MOUNTAIN. TEMPS SHOULD NOT FALL MORE THAN ANOTHER DEGREE BEFORE SUNRISE. ADDED ISOLATED FREEZING RAIN...BUT THE POTENTIAL REMAINS SMALL AT THIS TIME. AS A RESULT...WILL NOT ISSUE ANY SPS AT THIS TIME GIVEN THE PRECIP JUST STARTING TO CROSS THE BOARDER INTO CWA. THE POTENTIAL EXISTS FOR ANOTHER BAND OF MAINLY RAIN SHOWERS TO DEVELOP OVER THE E PORTIONS OF THE CWA...WITH FAVORABLE SE FLOW OFF LAKE SUPERIOR...AS MUCH OF THE INITIAL EARLY MORE SHOWER ACTIVITY PUSHES ENE INTO LAKE SUPERIOR. S-SW FLOW AND 850MB TEMPS RISING TO 3-6C OVER THE CENTRAL PORTIONS OF THE CWA SHOULD ALLOW TEMPS FROM BARAGA THROUGH AT LEAST MARQUETTE COUNTY TO BE A COUPLE DEGREES ABOVE WHAT THEY WOULD OTHERWISE BE THANKS TO DOWNSLOPE FLOW. AS FOR TONIGHT...LIGHTER WINDS SHOULD BE THE RULE AS THE FRONTAL BOUNDARY STRETCHING FROM LOWS OVER HUDSON BAY AND THE CENTRAL PLAINS SHIFTS FROM THE FAR W CWA TO OUR SE BY 12Z FRIDAY. THE MOISTURE PROFILE REMAINS PRETTY SHALLOW OVERNIGHT. STILL...A COUPLE OF FCST MODELS ARE INDICATING THE POTENTIAL FOR MIXED PRECIP /MAINLY RAIN OR FREEZING RAIN/ OVER N CENTRAL UPPER MI JUST PRIOR TO SUNRISE FRIDAY. WILL NOT PLACE THIS IN THE FORECAST QUITE YET...DUE TO THE UNCERTAINTY AND LIMITED PRECIP IF IT DOES HAPPEN...AROUND TRACE TO 0.01 INCHES OF LIQUID. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 533 AM EST THU NOV 8 2012 FRI INTO SAT...THE MID/UPPER LEVEL TROUGH OVER THE WEST COAST IS EXPECTED TO SLIDE EAST INTO THE GREAT BASIN AND ROCKIES RESULTING IN SW FLOW FROM THE PLAINS INTO THE NRN GREAT LAKES. AT THE SFC...AN AREA OF LOW PRES OVER THE ROCKIES WILL MOVE INTO THE CENTRAL PLAINS AND INTO MN. LOW LEVEL ERLY FLOW WILL STRENGTHEN AS THE PRES GRADIENT INCREASES BTWN A WARM FRONT LIFTING TO THE NORTH FROM WI AND A RIDGE FROM NRN SASK INTO NRN ONTARIO. EVEN THOUGH THE MODELS HAVE HINTED AT THE POTENTIAL FOR SOME PATCHY LIGHT RAIN OR DRIZZLE FRIDAY...WITH MAINLY WEAK ACYC FLOW PREVAILING AND ONLY WEAK LOW LEVEL UPWARD MOTION...CONFIDENCE WAS LOW THAT ANY MEASURABLE PCPN WILL DEVELOP. THE BEST CHANCE FOR ANY PCPN WOULD BE IN UPSLOPE LOCATIONS DOWNWIND OF LAKE SUPERIOR LATE IN THE DAY. AS THE LOW LIFTS INTO MN AND THE 850 WARM FRONT OVER WI LIFTS THROUGH UPPER MI...A BAND OF 295K-305K ISENTROPIC LIFT WILL STRENGTHEN ENOUGH TO SUPPORT LIKELY RAIN CHANCES THROUGH UPPER MI BY SATURDAY MORNING. WITH MUCAPE VALUES TO AROUND 400 J/KG BY SATURDAY AFTERNOON SOME TSRA MAY BE POSSIBLE. SAT NIGHT...AS THE LOW LIFTS THROUGH MN TO NEAR CYQT THE FOCUS FOR STRONGER ISENTROPIC LIFT ALONG THE 850-700 MB FRONT WILL ALOS LIFT NORTH OF THE AREA. HOWEVER...SOME SHOWERS WILL STILL BE POSSIBLE IN THE WARM SECTOR AS WEAK SHORTWAVES ARE LIKELY TO MOVE THROUGH THE AREA. SUN...THE BEST CHANCE FOR WIDEPSREAD MODERATE TO OCNLY HEAVY RAIN WILL BE ALONG THE COLD FRONT AS THE LOW LIFT TOWARDS JAMES BAY AND MOISTURE TRANSPORT PUSHES PWAT VALUES TO 1.00-1.25 INCH...250-300 PCT OF NORMAL. MUCAPE VALUES TO AROUND 400 J/KG ALSO SUGGEST THAT ISOLD TSRA WILL REMAIN POSSIBLE. GIVEN THE HIGH AMPLITUDE PATTERN...THE SLOWER ECMWF WAS PREFERRED WITH THE TIMING OF THE FRONT COMPARED TO THE GFS. MON INTO TUE...A PERIOD OF LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY WNW TO NW FLOW IS EXPECTED AS CAA DROPS 850 MB TEMPS TO AROUND -12C. THE GEFS/GFS AND ECMWF WERE SIMILAR WITH A QUICK TRANSITION TO MORE ZONAL FLOW BY TUE NIGHT WHICH WOULD END LES POTENTIAL AND BRING && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1228 PM EST THU NOV 8 2012 IMPROVING CONDITIONS AT THE TERMINALS EARLY THIS AFTERNOON AS WARM FRONTAL PRECIPITATION PUSHES EAST OF THE AREA IN ADVANCE OF A COLD FRONT THAT WILL SAG SOUTH THROUGH THE REGION TONIGHT. PRIMARY CONCERNS CENTER AROUND STRATUS DEVELOPMENT LATE TONIGHT AFTER BEHIND THE SAGGING COLD FRONT. UPSTREAM SATELLITE TRENDS AND OBSERVATIONS REVEALS SUBSTANTIAL STRATUS AT THIS HOUR...WHICH IS FAR MORE IN LINE WITH THE 12Z GFS /VS THE NAM/. GIVEN THIS EVOLUTION...WILL LEAN TOWARDS THE MORE PESSIMISTIC GFS/MAV/LAV GUIDANCE OVERNIGHT WHICH WILL SHOW MVFR CIGS /AND POTENTIALLY SOME LIGHT FOG/ DEVELOPING AFTER MIDNIGHT. GIVEN RELATIVELY WEAK FLOW OFF WARMER LAKE SUPERIOR FOR THE DAY ON FRIDAY...I DON/T EXPECT SIGNIFICANT IMPROVEMENT IN CIGS BEFORE THE END OF THE TAF PERIOD AT 18Z...ALTHOUGH ANY VSBY RESTRICTIONS WILL LIKELY COME TO AN END BY MID MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST THU NOV 8 2012 THE RIDGE OF HIGH PRESSURE OVER LAKE MI AND LAKE HURON WILL CONTINUE TO PUSH E AS A LOW ACROSS NW MN MOVES TO JAMES BAY THIS AFTERNOON. THIS WILL ALLOW A TROUGH TO SWING ACROSS SLAKE SUPERIOR TONIGHT. THIS WILL ALLOW S-SE GUSTS OF 25-30KTS OVER THE E THIRD OF LS. A RIDGE WILL TEMPORARILY BUILD ACROSS LS BEHIND THE TROUGH ON FRIDAY...WITH FUNNELING NE WINDS ACROSS W LS GUSTING 20-30KTS WOUND NOT BE OUT OF THE QUESTION FRIDAY THROUGH SATURDAY. A FEW GALE FORCE GUSTS MAY NEED TO BE MENTIONED FAR W SATURDAY. A DEEPER LOW ACROSS THE CENTRAL PLAINS SATURDAY MORNING WILL CROSS LS LATE SATURDAY && .MQT WATCHES/WARNINGS/ADVISORIES... MI...NONE. LS...NONE. LM...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST FRIDAY FOR LMZ248-250. && $$ UPDATE...ARNOTT SHORT TERM...KF LONG TERM...JLB AVIATION...ARNOTT MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1229 PM EST THU NOV 8 2012 .UPDATE... ISSUED AT 951 AM EST THU NOV 8 2012 LIGHT WARM ADVECTION /LIFT ON 295K SURFACE/ PRECIPITATION CONTINUES TO PUSH EAST THIS MORNING. MORNING INL/GRB/APX SOUNDING CONTINUES TO SHOW A REMNANT DRY WEDGE CENTERED AT H8...WHICH SUGGESTS THAT ANY OF THE RETURNS SEEN ON THE MQT 88D ARE LIKELY NO MORE THAN SPRINKLES. BEST ISENTROPIC ASCENT WILL CONTINUE TO SHIFT EAST AS THE DAY GOES ON...SO EXPECT ANY SPRINKLES TO GIVE WAY TO A DRY AFTERNOON. WITH THE BEST MOISTURE SHIFTING EAST AS THE DAY GOES ON...AND LOOKING AT UPSTREAM OBS OVER NORTHEAST MINNESOTA...SKIES WILL GRADUALLY IMPROVE /IWD ALREADY CLEARING AT THIS HOUR/...WITH PARTLY SUNNY SKIES OVERTAKING MOST OF THE CWA DURING THE AFTERNOON. CLOUDS WILL BE MOST STUBBORN OVER FAR EASTERN AREAS WITH MOIST PLUME OFF OF LAKE MICHIGAN POTENTIALLY IMPACTING MY FAR EASTERN ZONES THROUGH THE DAY GIVEN SOUTHWESTERLY LLEVEL FLOW. GOING FORECAST HAD THESE TRENDS WELL-HANDLED WITH ONLY MINOR TWEAKS TO POP/SKY TIMING. TEMPERATURES IN THE MID 40S EAST /MORE CLOUDS/ TO AROUND 50 WEST GIVEN T92S WARMING TO +2-4C IN THE AFOREMENTIONED WARM ADVECTION REGIME. UPDATE ISSUED AT 654 AM EST THU NOV 8 2012 SOME OF THE SHORTER SCALE FCST MODELS ARE HAVING A BETTER TIME HANDLING THE CURRENT SHOWER ACTIVITY OVER FAR W UPPER MI. UPDATED THE FCST /POPS/WX/QPF...WITH ASSISTANCE OF THE RUC GUIDANCE WHICH && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 533 AM EST THU NOV 8 2012 ALTHOUGH MUCH OF THE ENERGY WITH THE WEAK SHORTWAVE IS CROSSING TO OUR NORTH...INCREASED MOISTURE AHEAD OF THE NEXT SFC LOW OVER THE DAKOTAS HAS ALLOWED FOR A BROKEN LINE OF SHOWERS TO DEVELOP. AS OF 09Z NO CLOUD TO GROUND LIGHTNING HAS BEEN FOUND WITH THIS SYSTEM. WHILE TEMPERATURES ALOFT WOULD SUPPORT RAIN SHOWERS /850MB TEMPS OF 0-3C OVER N WI EARLY THIS MORNING/...POCKETS OF COOLER AIR NEAR THE SFC COULD RESULT IN LIGHT FREEZING RAIN. AT6 09Z THE ONLY LOCATIONS SHOWING UP ON THE MESONET BELOW FREEZING WERE PEAVY FALLS AND RANDVILLE...JUST NW OF IRON MOUNTAIN. TEMPS SHOULD NOT FALL MORE THAN ANOTHER DEGREE BEFORE SUNRISE. ADDED ISOLATED FREEZING RAIN...BUT THE POTENTIAL REMAINS SMALL AT THIS TIME. AS A RESULT...WILL NOT ISSUE ANY SPS AT THIS TIME GIVEN THE PRECIP JUST STARTING TO CROSS THE BOARDER INTO CWA. THE POTENTIAL EXISTS FOR ANOTHER BAND OF MAINLY RAIN SHOWERS TO DEVELOP OVER THE E PORTIONS OF THE CWA...WITH FAVORABLE SE FLOW OFF LAKE SUPERIOR...AS MUCH OF THE INITIAL EARLY MORE SHOWER ACTIVITY PUSHES ENE INTO LAKE SUPERIOR. S-SW FLOW AND 850MB TEMPS RISING TO 3-6C OVER THE CENTRAL PORTIONS OF THE CWA SHOULD ALLOW TEMPS FROM BARAGA THROUGH AT LEAST MARQUETTE COUNTY TO BE A COUPLE DEGREES ABOVE WHAT THEY WOULD OTHERWISE BE THANKS TO DOWNSLOPE FLOW. AS FOR TONIGHT...LIGHTER WINDS SHOULD BE THE RULE AS THE FRONTAL BOUNDARY STRETCHING FROM LOWS OVER HUDSON BAY AND THE CENTRAL PLAINS SHIFTS FROM THE FAR W CWA TO OUR SE BY 12Z FRIDAY. THE MOISTURE PROFILE REMAINS PRETTY SHALLOW OVERNIGHT. STILL...A COUPLE OF FCST MODELS ARE INDICATING THE POTENTIAL FOR MIXED PRECIP /MAINLY RAIN OR FREEZING RAIN/ OVER N CENTRAL UPPER MI JUST PRIOR TO SUNRISE FRIDAY. WILL NOT PLACE THIS IN THE FORECAST QUITE YET...DUE TO THE UNCERTAINTY AND LIMITED PRECIP IF IT DOES HAPPEN...AROUND TRACE TO 0.01 INCHES OF LIQUID. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 533 AM EST THU NOV 8 2012 FRI INTO SAT...THE MID/UPPER LEVEL TROUGH OVER THE WEST COAST IS EXPECTED TO SLIDE EAST INTO THE GREAT BASIN AND ROCKIES RESULTING IN SW FLOW FROM THE PLAINS INTO THE NRN GREAT LAKES. AT THE SFC...AN AREA OF LOW PRES OVER THE ROCKIES WILL MOVE INTO THE CENTRAL PLAINS AND INTO MN. LOW LEVEL ERLY FLOW WILL STRENGTHEN AS THE PRES GRADIENT INCREASES BTWN A WARM FRONT LIFTING TO THE NORTH FROM WI AND A RIDGE FROM NRN SASK INTO NRN ONTARIO. EVEN THOUGH THE MODELS HAVE HINTED AT THE POTENTIAL FOR SOME PATCHY LIGHT RAIN OR DRIZZLE FRIDAY...WITH MAINLY WEAK ACYC FLOW PREVAILING AND ONLY WEAK LOW LEVEL UPWARD MOTION...CONFIDENCE WAS LOW THAT ANY MEASURABLE PCPN WILL DEVELOP. THE BEST CHANCE FOR ANY PCPN WOULD BE IN UPSLOPE LOCATIONS DOWNWIND OF LAKE SUPERIOR LATE IN THE DAY. AS THE LOW LIFTS INTO MN AND THE 850 WARM FRONT OVER WI LIFTS THROUGH UPPER MI...A BAND OF 295K-305K ISENTROPIC LIFT WILL STRENGTHEN ENOUGH TO SUPPORT LIKELY RAIN CHANCES THROUGH UPPER MI BY SATURDAY MORNING. WITH MUCAPE VALUES TO AROUND 400 J/KG BY SATURDAY AFTERNOON SOME TSRA MAY BE POSSIBLE. SAT NIGHT...AS THE LOW LIFTS THROUGH MN TO NEAR CYQT THE FOCUS FOR STRONGER ISENTROPIC LIFT ALONG THE 850-700 MB FRONT WILL ALOS LIFT NORTH OF THE AREA. HOWEVER...SOME SHOWERS WILL STILL BE POSSIBLE IN THE WARM SECTOR AS WEAK SHORTWAVES ARE LIKELY TO MOVE THROUGH THE AREA. SUN...THE BEST CHANCE FOR WIDEPSREAD MODERATE TO OCNLY HEAVY RAIN WILL BE ALONG THE COLD FRONT AS THE LOW LIFT TOWARDS JAMES BAY AND MOISTURE TRANSPORT PUSHES PWAT VALUES TO 1.00-1.25 INCH...250-300 PCT OF NORMAL. MUCAPE VALUES TO AROUND 400 J/KG ALSO SUGGEST THAT ISOLD TSRA WILL REMAIN POSSIBLE. GIVEN THE HIGH AMPLITUDE PATTERN...THE SLOWER ECMWF WAS PREFERRED WITH THE TIMING OF THE FRONT COMPARED TO THE GFS. MON INTO TUE...A PERIOD OF LAKE EFFECT SNOW FOR LOCATIONS FAVORED BY WNW TO NW FLOW IS EXPECTED AS CAA DROPS 850 MB TEMPS TO AROUND -12C. THE GEFS/GFS AND ECMWF WERE SIMILAR WITH A QUICK TRANSITION TO MORE ZONAL FLOW BY TUE NIGHT WHICH WOULD END LES POTENTIAL AND BRING && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1228 PM EST THU NOV 8 2012 IMPROVING CONDITIONS AT THE TERMINALS EARLY THIS AFTERNOON AS WARM FRONTAL PRECIPITATION PUSHES EAST OF THE AREA IN ADVANCE OF A COLD FRONT THAT WILL SAG SOUTH THROUGH THE REGION TONIGHT. PRIMARY CONCERNS CENTER AROUND STRATUS DEVELOPMENT LATE TONIGHT AFTER BEHIND THE SAGGING COLD FRONT. UPSTREAM SATELLITE TRENDS AND OBSERVATIONS REVEALS SUBSTANTIAL STRATUS AT THIS HOUR...WHICH IS FAR MORE IN LINE WITH THE 12Z GFS /VS THE NAM/. GIVEN THIS EVOLUTION...WILL LEAN TOWARDS THE MORE PESSIMISTIC GFS/MAV/LAV GUIDANCE OVERNIGHT WHICH WILL SHOW MVFR CIGS /AND POTENTIALLY SOME LIGHT FOG/ DEVELOPING AFTER MIDNIGHT. GIVEN RELATIVELY WEAK FLOW OFF WARMER LAKE SUPERIOR FOR THE DAY ON FRIDAY...I DON/T EXPECT SIGNIFICANT IMPROVEMENT IN CIGS BEFORE THE END OF THE TAF PERIOD AT 18Z...ALTHOUGH ANY VSBY RESTRICTIONS WILL LIKELY COME TO AN END BY MID MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 533 AM EST THU NOV 8 2012 THE RIDGE OF HIGH PRESSURE OVER LAKE MI AND LAKE HURON WILL CONTINUE TO PUSH E AS A LOW ACROSS NW MN MOVES TO JAMES BAY THIS AFTERNOON. THIS WILL ALLOW A TROUGH TO SWING ACROSS SLAKE SUPERIOR TONIGHT. THIS WILL ALLOW S-SE GUSTS OF 25-30KTS OVER THE E THIRD OF LS. A RIDGE WILL TEMPORARILY BUILD ACROSS LS BEHIND THE TROUGH ON FRIDAY...WITH FUNNELING NE WINDS ACROSS W LS GUSTING 20-30KTS WOUND NOT BE OUT OF THE QUESTION FRIDAY THROUGH SATURDAY. A FEW GALE FORCE GUSTS MAY NEED TO BE MENTIONED FAR W SATURDAY. A DEEPER LOW ACROSS THE CENTRAL PLAINS SATURDAY MORNING WILL CROSS LS LATE SATURDAY && .MQT WATCHES/WARNINGS/ADVISORIES... MI...NONE. LS...NONE. LM...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST FRIDAY FOR LMZ248-250. && $$ UPDATE...ARNOTT SHORT TERM...KF LONG TERM...JLB AVIATION...ARNOTT MARINE...KF
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
429 PM EST THU NOV 8 2012 .SYNOPSIS... HIGH PRESSURE WILL KEEP DRY CONDITIONS AND MOSTLY CLEAR SKIES INTO THIS WEEKEND. AS THE HIGH SHIFTS EASTWARD FRIDAY...A WARMING TREND WILL BEGIN THAT WILL BRING UNSEASONABLY WARM TEMPERATURES FOR THE WEEKEND. THE NEXT CHANCE FOR RAIN WILL OCCUR LATE SUNDAY NIGHT INTO MONDAY WITH THE APPROACH AND PASSAGE OF A COLD FRONT. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... HIGHLY AMPLIFIED PATTERN WITH AN UPPER LEVEL RIDGE OVER THE NATIONS MID SECTION TO BEGIN BUILDING EAST INTO THE REGION. SURFACE RIDGE AXIS OVER THE OHIO VALLEY TO SLIDE JUST TO OUR EAST LATE TONIGHT WITH THE LOW LEVEL FLOW BECOMING SRLY. MSTR BETWEEN 900-850MB LOCATED TO OUR WEST OVER INDIANA BEGINNING TO PUSH INTO W CNTRL OHIO. QUESTION REVOLVES AROUND HOW THESE CLOUDS WILL AFFECT ILN/S FA. THE FLOW AT THIS LEVEL BECOMES WESTERLY AROUND 15 KTS WHICH WILL ALLOW THE CLOUDS TO CONTINUE TO PUSH EAST INTO ILN/S WESTERN FA EARLY THIS EVENING. IN WAA PATTERN EXPECT A GENERAL DECREASE IN COVERAGE OF THESE CLOUDS AS THEY PUSH EAST. LATEST RAP RUN SUPPORTS THIS SOLN BRINGING THE BEST COVERAGE OF CLOUDS INTO WEST CNTRL OHIO THIS EVENING AND THEN DIMINISHING THEM. OTHERWISE...EXPECT MAINLY CLEAR SKY CONDITIONS WITH ONLY SOME HIGH LEVEL CLOUDS SPILLING IN. EXPECT LOWS TO BE A LTL MILDER THAN THIS MORNING...RANGING FROM UPPER 20S NE TO THE LOWER/MID 30S SW. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... UPPER LEVEL RIDGE TO BUILD EAST INTO THE REGION ON FRIDAY. THIS WILL ALLOW FOR HEIGHT/THICKNESS RISES. EXPECT MAINLY SUNNY SKY CONDITIONS FRIDAY WITH ONLY THIN HIGH LEVEL CLOUDS SPILLING IN. UNDER WAA AND SUNSHINE EXPECT HIGHS TO BE 5 TO 10 DEGREES ABOVE NORMAL...RANGING FROM THE MID 50S NE TO THE LOWER 60S SW. ISENTROPIC LIFT DEVELOPS LAT FRIDAY AFTN/FRIDAY NIGHT WITH THE BEST LIFT AND MOISTURE TO REMAIN TO OUR NORTH ACRS THE GREAT LAKES. WILL ALLOW FOR AN INCREASE IN MID/HI LEVEL CLOUDS FRIDAY NIGHT WITH THE BEST COVERAGE ACRS THE NORTH. THESE CLOUDS AND SRLY FLOW WILL KEEP TEMPS ON THE MILD SIDE FRIDAY NIGHT. LOWS ARE EXPECTED TO RANGE FROM THE UPPER 30S NE TO THE LOWER/MID 40S SW. GOOD WAA ON SATURDAY WITH THINNING CLOUDS ALLOWING FOR MOSTLY SUNNY SKY CONDITIONS. 8H TEMPS WARM UP TO BETWEEN +13 AD +14 DEG C. EXPECT HIGHS TO BE ABOUT 15 DEGREES ABOVE NORMAL...RANGING FROM THE MID 60S NORTH TO NEAR 70 SOUTH. SOME INCREASE IN HIGH LEVEL CLOUDS LKLY SAT NIGHT. UNDER CONTD SRLY FLOW MILD CONDITIONS WILL PERSIST WITH LOWS RANGING FROM THE MID 40S E TO THE UPPER 40S W. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A SOUTHERLY FLOW BEHIND DEPARTING HIGH PRESSURE WILL KEEP WARM... BREEZY AND DRY CONDITIONS OVER THE REGION ON SUNDAY. A STRONG COLD FRONT WILL AFFECT THE AREA ON MONDAY. WENT WITH CATEGORICAL SHOWERS...AND ISOLATED THUNDERSTORMS IN A REGIME OF MARGINAL ELEVATED INSTABILITY. SYNOPTIC SCALE WINDS ACCOMPANYING THE FRONT MAY GUST NEAR 25 KNOTS. MODELS INDICATE A RATHER RAPID EXIT FOR THE FRONT...WITH DRY WEATHER RETURNING ON TUESDAY. THE DRY PERIOD IS EXPECTED TO LAST THROUGH THURSDAY AS HIGH PRESSURE TRAVELS ACROSS OHIO ON A WESTERLY FLOW ALOFT. TEMPERATURES WILL RISE INTO THE 60S ON SUNDAY UNDER MOSTLY SUNNY SKIES. HIGHS IN THE 50S AND 60S ARE FORECAST FOR MONDAY DURING THE TRANSITION TO A COOLER AIRMASS BEHIND THE FRONT. READINGS ON TUESDAY AND WEDNESDAY WILL TOP OUT IN THE 40S...WITH A RISE TO AROUND 50 POSSIBLE THURSDAY IN THE RETURN FLOW BEHIND THE HIGH. && .AVIATION /22Z THURSDAY THROUGH TUESDAY/... A SURFACE HIGH PRESSURE RIDGE AXIS WILL MOVE ACROSS THE REGION THROUGH THIS EVENING...MOVING EAST OF THE REGION OVERNIGHT. MEANWHILE...A MID LEVEL RIDGE WILL BUILD EAST INTO THE OHIO VALLEY THROUGH THE TAF PERIOD. PER VISIBLE SATELLITE IMAGERY...A FEW DIURNAL CUMULUS CLOUDS WERE FORMING ACROSS THE REGION. THESE SHOULD DISSIPATE AFTER SUNSET. A STRATOCUMULUS DECK OVER ILLINOIS AND INDIANA THIS AFTERNOON SHOULD ADVECT EAST/NORTHEAST INTO THE AREA TONIGHT. SOME EROSION/CUMULUS DEVELOPMENT IS ALREADY OCCURRING ON THE EDGES OF THIS DECK...SO IT IS UNCLEAR HOW MUCH OF THIS WILL REMAIN AS A SOLID DECK AS IT SLOWLY PUSHES EAST/NORTHEAST. HAVE LEFT SCATTERED CLOUDS AT KDAY FOR THE EVENING HOURS WHILE KEEPING THE REST OF THE AREA CLEAR. WILL CONTINUE TO MONITOR SATELLITE AND OBSERVATIONAL TRENDS FOR ANY POTENTIAL CHANGES TO THE TAFS. FOG POTENTIAL OVERNIGHT INTO THURSDAY MORNING SHOULD BE AT KLUK DUE TO RIVER VALLEY FOG. HAVE PLACED BELOW AIRPORT MINIMUMS IN THE TAF. FOG SHOULD BURN OFF BETWEEN 14Z AND 16Z. .OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY INTO MONDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...AR LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
428 PM EST THU NOV 8 2012 .SYNOPSIS... HIGH PRESSURE WILL KEEP DRY CONDITIONS AND MOSTLY CLEAR SKIES INTO THIS WEEKEND. AS THE HIGH SHIFTS EASTWARD FRIDAY...A WARMING TREND WILL BEGIN THAT WILL BRING UNSEASONABLY WARM TEMPERATURES FOR THE WEEKEND. THE NEXT CHANCE FOR RAIN WILL OCCUR LATE SUNDAY NIGHT INTO MONDAY WITH THE APPROACH AND PASSAGE OF A COLD FRONT. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... HIGHLY AMPLIFIED PATTERN WITH AN UPPER LEVEL RIDGE OVER THE NATIONS MID SECTION TO BEGIN BUILDING EAST INTO THE REGION. SURFACE RIDGE AXIS OVER THE OHIO VALLEY TO SLIDE JUST TO OUR EAST LATE TONIGHT WITH THE LOW LEVEL FLOW BECOMING SRLY. MSTR BETWEEN 900-850MB LOCATED TO OUR WEST OVER INDIANA BEGINNING TO PUSH INTO W CNTRL OHIO. QUESTION REVOLVES AROUND HOW THESE CLOUDS WILL AFFECT ILN/S FA. THE FLOW AT THIS LEVEL BECOMES WESTERLY AROUND 15 KTS WHICH WILL ALLOW THE CLOUDS TO CONTINUE TO PUSH EAST INTO ILN/S WESTERN FA EARLY THIS EVENING. IN WAA PATTERN EXPECT A GENERAL DECREASE IN COVERAGE OF THESE CLOUDS AS THEY PUSH EAST. LATEST RAP RUN SUPPORTS THIS SOLN BRING THE BEST COVERAGE OF CLOUDS INTO S CNTRL OHIO THIS EVENING AND THEN DIMINISHING THEM. OTHERWISE...EXPECT MAINLY CLEAR SKY CONDITIONS WITH ONLY SOME HIGH LEVEL CLOUDS SPILLING IN. EXPECT LOWS TO BE A LTL MILDER THAN THIS MORNING...RANGING FROM UPPER 20S NE TO THE LOWER/MID 30S SW. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... UPPER LEVEL RIDGE TO BUILD EAST INTO THE REGION ON FRIDAY. THIS WILL ALLOW FOR HEIGHT/THICKNESS RISES. EXPECT MAINLY SUNNY SKY CONDITIONS FRIDAY WITH ONLY THIN HIGH LEVEL CLOUDS SPILLING IN. UNDER WAA AND SUNSHINE EXPECT HIGHS TO BE 5 TO 10 DEGREES ABOVE NORMAL...RANGING FROM THE MID 50S NE TO THE LOWER 60S SW. ISENTROPIC LIFT DEVELOPS LAT FRIDAY AFTN/FRIDAY NIGHT WITH THE BEST LIFT AND MOISTURE TO REMAIN TO OUR NORTH ACRS THE GREAT LAKES. WILL ALLOW FOR AN INCREASE IN MID/HI LEVEL CLOUDS FRIDAY NIGHT WITH THE BEST COVERAGE ACRS THE NORTH. THESE CLOUDS AND SRLY FLOW WILL KEEP TEMPS ON THE MILD SIDE FRIDAY NIGHT. LOWS ARE EXPECTED TO RANGE FROM THE UPPER 30S NE TO THE LOWER/MID 40S SW. GOOD WAA ON SATURDAY WITH THINNING CLOUDS ALLOWING FOR MOSTLY SUNNY SKY CONDITIONS. 8H TEMPS WARM UP TO BETWEEN +13 AD +14 DEG C. EXPECT HIGHS TO BE ABOUT 15 DEGREES ABOVE NORMAL...RANGING FROM THE MID 60S NORTH TO NEAR 70 SOUTH. SOME INCREASE IN HIGH LEVEL CLOUDS LKLY SAT NIGHT. UNDER CONTD SRLY FLOW MILD CONDITIONS WILL PERSIST WITH LOWS RANGING FROM THE MID 40S E TO THE UPPER 40S W. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A SOUTHERLY FLOW BEHIND DEPARTING HIGH PRESSURE WILL KEEP WARM... BREEZY AND DRY CONDITIONS OVER THE REGION ON SUNDAY. A STRONG COLD FRONT WILL AFFECT THE AREA ON MONDAY. WENT WITH CATEGORICAL SHOWERS...AND ISOLATED THUNDERSTORMS IN A REGIME OF MARGINAL ELEVATED INSTABILITY. SYNOPTIC SCALE WINDS ACCOMPANYING THE FRONT MAY GUST NEAR 25 KNOTS. MODELS INDICATE A RATHER RAPID EXIT FOR THE FRONT...WITH DRY WEATHER RETURNING ON TUESDAY. THE DRY PERIOD IS EXPECTED TO LAST THROUGH THURSDAY AS HIGH PRESSURE TRAVELS ACROSS OHIO ON A WESTERLY FLOW ALOFT. TEMPERATURES WILL RISE INTO THE 60S ON SUNDAY UNDER MOSTLY SUNNY SKIES. HIGHS IN THE 50S AND 60S ARE FORECAST FOR MONDAY DURING THE TRANSITION TO A COOLER AIRMASS BEHIND THE FRONT. READINGS ON TUESDAY AND WEDNESDAY WILL TOP OUT IN THE 40S...WITH A RISE TO AROUND 50 POSSIBLE THURSDAY IN THE RETURN FLOW BEHIND THE HIGH. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... A SURFACE HIGH PRESSURE RIDGE AXIS WILL MOVE ACROSS THE REGION THROUGH THIS EVENING...MOVING EAST OF THE REGION OVERNIGHT. MEANWHILE...A MID LEVEL RIDGE WILL BUILD EAST INTO THE OHIO VALLEY THROUGH THE TAF PERIOD. PER VISIBLE SATELLITE IMAGERY...A FEW DIURNAL CUMULUS CLOUDS WERE FORMING ACROSS THE REGION. THESE SHOULD DISSIPATE AFTER SUNSET. A STRATOCUMULUS DECK OVER ILLINOIS AND INDIANA THIS AFTERNOON SHOULD ADVECT EAST/NORTHEAST INTO THE AREA TONIGHT. SOME EROSION/CUMULUS DEVELOPMENT IS ALREADY OCCURRING ON THE EDGES OF THIS DECK...SO IT IS UNCLEAR HOW MUCH OF THIS WILL REMAIN AS A SOLID DECK AS IT SLOWLY PUSHES EAST/NORTHEAST. HAVE LEFT SCATTERED CLOUDS AT KDAY FOR THE EVENING HOURS WHILE KEEPING THE REST OF THE AREA CLEAR. WILL CONTINUE TO MONITOR SATELLITE AND OBSERVATIONAL TRENDS FOR ANY POTENTIAL CHANGES TO THE TAFS. FOG POTENTIAL OVERNIGHT INTO THURSDAY MORNING SHOULD BE AT KLUK DUE TO RIVER VALLEY FOG. HAVE PLACED BELOW AIRPORT MINIMUMS IN THE TAF. FOG SHOULD BURN OFF BETWEEN 14Z AND 16Z. .OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE MONDAY INTO MONDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...AR LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS MEDFORD OR
920 AM PST THU NOV 8 2012 .DISCUSSION...A COLD UPPER LEVEL TROUGH IS CENTERED OFFSHORE FROM NORTHERN OREGON WHILE ITS ASSOCIATED COLD FRONT HAS REACHED THE WEST SIDE VALLEYS. THIS SYSTEM IS MOST NOTABLE FOR HOW COLD IT IS, RATHER THAN THE AMOUNT OF PRECIPITATION IT WILL PRODUCE. TYPICAL AMOUNTS AT ELEVATIONS ABOVE 3000 FEET WILL BE 1 TO 3 INCHES WITH LOCAL AMOUNTS TO 6 INCHES AT THE HIGHER ELEVATIONS...SUCH AS AROUND CRATER LAKE. THE FRONT WILL WEAKEN AS IT REACHES THE EAST SIDE THIS AFTERNOON BUT THERE WILL BE NUMEROUS POST-FRONTAL SHOWERS AND SNOW SHOWERS. THE SNOW LEVEL WILL BE AROUND 2500 TO 3000 FEET TODAY THEN FALL TO AROUND 2000 FEET TONIGHT. A SURFACE TROUGH WILL FOLLOW ON FRIDAY WITH ADDITIONAL SHOWERS AND SNOW SHOWERS THROUGH FRIDAY NIGHT. THE MAIN ITEM OF INTEREST FOR THE AFTERNOON FORECAST ISSUANCE WILL BE HOW MUCH TO LEAN TOWARD THE GFS SOLUTION OF A DEVELOPING SHORTWAVE AND DEFORMATION ZONE WITH HIGHER SNOW AMOUNTS POSSIBLE TONIGHT IN SOUTHERN KLAMATH AND SOUTHERN LAKE COUNTIES. BROAD, BUT WEAK RIDGING IS LIKELY OVER THE WEEKEND WITH THE NEXT FRONTAL SYSTEM APPROACHING TOWARD THE END OF THE WEEKEND. && .AVIATION...A MAJOR SHIFT IN THE WEATHER PATTERN IS EXPECTED TO IMPACT FLYING ACROSS THE FORECAST AREA TODAY AND TONIGHT. WIDESPREAD MVFR WITH LOCAL IFR AND TERRAIN OBSCURATIONS WILL OCCUR ACROSS THE WEST SIDE AS A COLD FRONT PUSHES INLAND EARLY THIS MORNING. WE`LL SEE A TRANSITION TO A MORE SHOWERY PATTERN BEHIND THE FRONT TODAY. SO, EXPECT A MIX OF VFR AND MVFR WITH ISOLATED IFR IN HEAVIER SNOW SHOWERS, BUT MOUNTAIN OBSCURATIONS WILL BECOME WIDESPREAD. WITH THE ARRIVAL OF VERY COLD AIR ALOFT, SOME SMALL HAIL/GRAUPEL MAY ACCOMPANY ANY OF THE HEAVIER SHOWERS AT LOWER ELEVATIONS, WHILE SNOW LEVELS FALL TO BETWEEN 2500 AND 3000 FEET BY THURSDAY EVENING. ISOLATED THUNDER ALSO CANNOT BE RULED OUT ALONG THE COAST. WEST SIDE SNOW LEVELS WILL DROP AS LOW AS 1500 FEET BY FRIDAY MORNING. EAST OF THE CASCADES, EXPECT MOSTLY VFR EARLY THIS MORNING, BUT AN AREA OF MVFR CIGS WITH -SHRA/-SHSN WILL EXTEND FROM EASTERN SISKIYOU COUNTY TO SOUTHERN LAKE AND MODOC COUNTIES BY LATE MORNING AND INTO THE AFTERNOON. MOUNTAIN OBSCURATION WILL BECOME PREVALENT BY THIS AFTERNOON. EAST SIDE SNOW LEVELS WILL BE AT VALLEY FLOORS TODAY AS COLDER AIR MOVES IN. LATER TODAY AND TONIGHT...EXPECT A MIX OF VFR AND MVFR BUT LOCAL IFR IN ANY HEAVIER SNOW SHOWERS. SPILDE/KEENE && .PREV DISCUSSION... /ISSUED 351 AM PST THU NOV 8 2012/ DISCUSSION...A SHORTWAVE TROUGH...REPRESENTING A SECONDARY PUSH OF COLD AIR...IS APPROACHING THE COAST THIS MORNING. CLOUD TOPS ARE COOLING...SUGGESTING A STRENGTHENING SHORTWAVE AND THE FIRST SIGNS OF PRECIPITATION ARE SHOWING UP ON RADAR RETURNS AT THE COAST. LATEST RAP MODEL DEPICTS A BAND OF SHOWERS PUSHING INTO THE COAST BY 8AM AND THEN MOVING INLAND TO JACKSON COUNTY BY 11AM. SNOW LEVELS ARE CURRENTLY ABOUT 3000 FEET JUST INLAND FROM THE COAST...AND SHOULD BE ABOUT 2000 FEET AS THE FIRST BAND OF SHOWERS MOVES IN. THE HEAVIEST SHOWERS THIS MORNING COULD IMPACT ROADWAYS LIKE INTERSTATE 5 AT SEXTON SUMMIT...AND PERHAPS HAYES HILL. THIS AFTERNOON WINTER WEATHER IMPACTS WILL SHIFT EASTWARD TO SISKIYOU SUMMIT WHERE ROAD TEMPERATURES SHOULD COOL AND ALLOW FOR SOME ACCUMULATION ON THE ROADWAYS. AFTER SUNSET...AS ROAD TEMPERATURES COOL AND SHOWERS CONTINUE...IMPACTS TO ROADWAYS ARE MORE LIKELY. A WINTER WEATHER ADVISORY AT WSWMFR HAS BEEN ISSUED FOR MUCH OF JOSEPHINE COUNTY ABOVE 1500 FEET AND THE SISKIYOUS AND CASCADES...TO INCLUDE I-5 AT SISKIYOU SUMMIT AND HWY 140 AT LAKE OF THE WOODS. EVEN THOUGH SNOW AMOUNTS ARE NOT EXPECTED TO RIVAL SIGNIFICANT MIDWINTER STORMS...ONLY AMOUNTING TO SEVERAL INCHES...THE SHARP TRANSITION TO LOW SNOW LEVELS AND THE EARLY SEASON NATURE OF THIS STORM WARRANTED A PRODUCT TO HIGHLIGHT POTENTIAL IMPACTS. THE ROGUE VALLEY HAS THE POTENTIAL OF SEEING SOME SNOWFLAKES TONIGHT...BUT SHOWERS ARE NOT EXPECTED TO BE HEAVY ENOUGH TO LOWER ROAD TEMPERATURES BELOW FREEZING...SO ANY SNOW SHOULD MELT QUICKLY ON ROADWAYS. CONFIDENCE ON THE SNOW POTENTIAL EAST OF THE CASCADES IS LOWER THAN THE REST OF THE AREA. THIS IS BECAUSE RECENT MODELS HAVE TRENDED UPWARD FROM LITTLE SNOW TO POTENTIALLY SEVERAL INCHES OF SNOW. THE MECHANISM APPEARS TO BE A DEFORMATION ZONE ALOFT AND STRONG LOW LEVEL CONVERGENCE. IN ANY CASE...HAVE BUMPED UP POPS SIGNIFICANTLY AND HAVE ISSUED A WINTER WEATHER ADVISORY...AGAIN AT WSWMFR...FOR MOST PLACES EAST OF THE CASCADES. THE GENERAL IDEA IS FOLKS COULD GO TO SLEEP TONIGHT WITH LITTLE TO NO SNOW ACCUMULATION AND WAKE UP TO A FEW INCHES OF SNOW AND SNOW COVERED ROADS. A GRADUAL DECREASE IN SHOWER ACTIVITY IS EXPECTED FRIDAY INTO SATURDAY...WITH DRY WEATHER AND WARMER TEMPERATURES EXPECTED ON SUNDAY. ANOTHER IMPULSE ON FRIDAY COULD GENERATE SIGNIFICANT SHOWERS WEST OF THE CASCADES AND HAVE BUMPED UP POPS FOR THAT AREA AND TIMEFRAME. WITH CONTINUED RELATIVELY LOW SNOW LEVELS...THIS WILL HAVE TO BE MONITORED. /KEENE && .MFR WATCHES/WARNINGS/ADVISORIES... OR...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM PST FRIDAY FOR ORZ029>031. WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR ORZ024. WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM PST FRIDAY FOR ORZ027-028. CA...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM PST FRIDAY FOR CAZ082>085. WINTER WEATHER ADVISORY UNTIL 4 AM PST FRIDAY FOR CAZ080. PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 1 PM THIS AFTERNOON TO 10 PM PST FRIDAY FOR PZZ350-356. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST FRIDAY FOR PZZ370-376. $$ DW
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
356 PM CST THU NOV 8 2012 .DISCUSSION.../ISSUED AT 356 PM CST/ FRONTAL BOUNDARY WILL CONTINUE TO WORK ITS WAY SOUTHEAST ACROSS THE CWA THIS AFTERNOON AND EVENING. MAIN FORECAST ISSUE TONIGHT INTO TOMORROW WILL BE CLOUD COVER AND TEMPERATURES. STRATUS DECK ASSOCIATED WITH THE LOW LEVEL COLD AIR ADVECTION PUSH IS CURRENTLY MOVING SOUTH INTO NORTHERN SOUTH DAKOTA. MODELS HANDLE THIS FEATURE DIFFERENTLY. LOOKS LIKE THE NAM IS DECOUPLING THE BOUNDARY LAYER TOO MUCH TONIGHT...WHICH ACTS TO KEEP THE STRATUS AT BAY. FEEL LIKE SOMETHING CLOSER TO THE RAP SOLUTION IS MOST LIKELY...WHERE THE COLD AIR ADVECTION KEEPS THE BOUNDARY LAYER MIXED ENOUGH TO KEEP THE STRATUS LOCKED IN AND SPREADING SOUTH. COULD EVEN SEE SOME SPOTTY DRIZZLE IN THE EASTERLY UPSLOPE LOCATIONS OF SOUTHWEST MINNESOTA. THUS WILL LEAN TOWARDS THIS SOLUTION WITH CLOUDS INCREASING FROM NORTH TO SOUTH TONIGHT. LOWS MAINLY IN THE 30S...WITH THE CLOUDS AND BREEZE PREVENTING TEMPS FROM FALLING TOO FAR. ON FRIDAY...LOW STRATUS WILL BEGIN TO ERODE FROM SOUTH TO NORTH. HOWEVER AT THE SAME TIME...SOUTHEASTERLY WINDS WILL ADVECT IN ADDITIONAL MOISTURE AROUND 850 MB...ALLOWING ANOTHER STRATUS DECK TO QUICKLY FORM. THUS THINK MUCH OF THE AREA STAYS CLOUDY THROUGH THE DAY...WITH SOUTHERN AREAS HAVING THE BEST CHANCE OF SEEING A BIT OF MORNING SUN. MOISTURE WILL CONTINUE TO DEEPEN THROUGH THE DAY...WITH PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA POSSIBLY SEEING SOME DRIZZLE BY MID AFTERNOON AS WE SEE WEAK LIFT IN THE NEARLY SATURATED 0-1 KM LAYER. FORECAST CONFIDENCE IS OVERALL PRETTY LOW ON FRIDAY. THE NAM IS A LOT SLOWER THAN THE GFS WITH STRATUS FORMATION...WITH THE GFS THE FASTEST. THE FORECAST FOLLOWS CLOSEST TO THE GFS SOLUTION...WHICH APPEARS TO BE HANDLING THINGS BEST AT THE CURRENT TIME. THUS WITH THE CLOUDS AROUND...LOWERED HIGHS A FEW DEGREES FOR TOMORROW...GENERALLY MID TO UPPER 40S NORTH TO MID 50S SOUTHEAST. IF A SOLUTION CLOSER TO THE NAM PANS OUT RESULTING IN A LONGER PERIOD OF SUN...HIGHS WILL BE A GOOD 5 DEGREES WARMER...AND IF THE CLOUDS STAY LOCKED IN EVEN MORE THAN EXPECTED...HIGHS WOULD BE A FEW DEGREES COOLER THAN CURRENT FORECAST. /CHENARD COMPLICATED FORECAST ANTICIPATED FOR THE WEEKEND WITH THE WELL ADVERTISED SURFACE LOW AND BROAD SURFACE TROUGH TRACKING THROUGH THE AREA. FOR FRIDAY NIGHT...LOW STRATUS WILL REMAIN A CONCERN WITH ALL MODELS KEEPING A LOW CLOUD DECK IN PLACE OVERNIGHT. THE GFS AND ECMWF CONTINUE TO INDICATE A DEEPER MOIST LAYER THAN THE NAM...WHICH POINTS TO A GREATER POTENTIAL FOR LIGHT FOG/MIST INSTEAD. HAVE OPTED TO FOLLOW THE GFS/ECMWF AND THE POTENTIAL FOR SOME DRIZZLE OR VERY LIGHT RAIN POSSIBLE IN OUR NORTHEAST CORNER OVERNIGHT. LOWER VISIBILITIES OR MIST WOULD BE REASONABLE IN THIS AREA AS WELL...BUT DO NOT THINK THE FOG WILL BE DENSE ENOUGH TO MENTION IN THE GRIDS. TEMPERATURES WILL BE QUITE MILD OVERNIGHT IN THE 40S. SATURDAY HAS THE POTENTIAL FOR BEING A VERY MILD DAY...PARTICULARLY ACROSS OUR EASTERN HALF. THE SURFACE LOW GRADUALLY LIFTS NORTH NORTHEAST THROUGH THE CENTER OF THE CWA INTO SOUTHWEST MINNESOTA. IT DOES LOOK LIKE THE STRATUS WILL BEGIN TO BREAK EARLY IN THE DAY ACROSS OUR EAST AS THE WARM FRONT LIFTS NORTH AND SOUTHERLY FLOW TAKES OVER. COULD SEE SOME WEAK MID LEVEL INSTABILITY IN THIS WARM SECTOR IN THE AFTERNOON AND EVENING ACROSS NORTHWEST IOWA WHICH WOULD BRING AN ISOLATED THREAT FOR SOME THUNDERSTORMS IN ADDITION TO THE RAIN SHOWERS WHICH SHOULD BEGIN WORKING INTO THE AREA. THE COLD FRONT FINALLY KICKS THROUGH OUR EASTERN HALF BY LATE SATURDAY EVENING...WITH THE STRATIFORM PRECIPITATION SPREADING THROUGH THE REMAINDER OF THE FORECAST AREA BEHIND IT. MUCH COLDER AIR WILL QUICKLY ARRIVE OVERNIGHT...TRANSITIONING THE RAIN TO A MIX AND THEN ENTIRELY SNOW BY DAYBREAK. FOR EARLY SUNDAY...THE LINGERING MID LEVEL EXITS TO OUR EAST WITH COOLER AND DRIER AIR WORKING INTO THE REGION. THE NAM IS THE FASTEST IN EXITING THE WAVE WITH THE BULK OF THE EVENT OVER LATE SUNDAY NIGHT...WHILE THE GFS AND ECMWF SUGGEST A LINGERING BAND OF LIGHT SNOW OVER THE FORECAST AREA INTO MID DAY. THE BULK OF THE SNOW WILL BE OVER AT THIS POINT...BUT HAVE HELD ONTO A CHANCE FOR THE MORNING. THE HIGHEST SNOWFALL AMOUNTS ARE EXPECTED WEST OF THE JAMES RIVER WHERE 2 TO 3 INCHES ARE EXPECTED...WHILE NORTHWEST IOWA CAN EXPECT A HALF INCH OR LESS. VERY BRISK NORTHWEST WINDS WILL COMBINE WITH HIGHS ONLY TOPPING OUT IN THE MID 20S TO MID 30S. IN THE EXTENDED...QUIETER WEATHER IS ON TAP EARLY NEXT WEEK INTO MID WEEK AS THE PATTERN TRANSITIONS INTO A MORE ZONAL FLOW. HIGHS ON MONDAY WILL REMAIN COLD IN THE UPPER 20S TO LOWER 30S...THEN GRADUALLY MODERATE INTO THE 40S BY MID WEEK. DID DROP LOWS A FEW DEGREES BELOW THE ALLBLEND ON SUNDAY NIGHT...BUT SOME LINGERING WINDS WOULD LIKELY PREVENT TEMPERATURES FROM REALLY DROPPING OFF. LOWS WILL BE IN THE TEENS SUNDAY NIGHT AND MONDAY NIGHT. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ VFR CONDITIONS EXPECTED TO PERSIST THROUGH THE DAY...WITH LOWERING CIGS POSSIBLE TONIGHT. NORTHERLY WIND GUSTS UP TO 20 KTS ARE LIKELY THIS AFTERNOON WEST OF INTERSTATE 29 AFTER THE FRONTAL PASSAGE. GUSTS AROUND 20 KTS ARE ALSO EXPECTED AHEAD OF THE FRONT ACROSS PORTIONS OF SOUTHWEST MINNESOTA AND NORTHWEST IOWA. LOW CONFIDENCE FORECAST TONIGHT INTO TOMORROW MORNING WITH REGARD TO CEILINGS. TEND TO BELIEVE THE FASTER MODEL SOLUTIONS BRINGING IN THE STRATUS FROM THE NORTH...WHICH WOULD BRING IT INTO HURON BEFORE MIDNIGHT...SIOUX FALLS BY MIDNIGHT AND SIOUX CITY A FEW HOURS LATER. THE SLOWER MODEL SOLUTIONS SEEM TO BE POORLY REPRESENTING THE BOUNDARY LAYER EVOLUTION AND THUS WERE DISCARDED AT THIS TIME. BUT STILL SOMETHING TO WATCH...AS MVFR CIGS COULD ARRIVE A FEW HOURS EITHER SIDE OF THE CURRENT FORECAST. THINK THAT EVEN A FEW HOURS OF IFR IS POSSIBLE INTO THE MORNING HOURS...THUS INCLUDED A TEMPO FOR NOW UNTIL CONFIDENCE INCREASES TONIGHT. /CHENARD && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$