Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/20/12


AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
905 PM EST MON NOV 19 2012 .UPDATE...STRONG NORTH WINDS CONTINUE OVER THE COASTAL WATERS WHERE THE GRADIENT IS TIGHTER DUE TO LOW PRESSURE OFF THE EAST CENTRAL FL COAST. WINDS ARE LIGHT OVER LAND...DECREASING TO LESS THAN 10 MPH. SHORT WAVE ALOFT HAS SPREAD CIRRUS OVER THE AREA WHILE LOW CLOUDS PERSIST BETWEEN 1-4KFT. NAM12 AND RUC MODELS SHOW DECREASING CLOUDS FROM THE NORTH TONIGHT BUT WILL KEEP MOSTLY CLOUDY FOR MOST OF THE NIGHT DUE TO ADVECTION OF LOW CLOUDS UPSTREAM. WILL BUMP UP MIN TEMPS TONIGHT A DEGREE OR TWO. && .AVIATION...PREVAILING MVFR CIGS AROUND FL015-025 EXPECTED THIS EVENING FOR TAF SITES BUT SHORT TERM GUIDANCE INDICATES CIGS MAY ERODE FROM N TO S...MAINLY ALONG THE COASTAL SE GA AREA AFTER MIDNIGHT. HAVE SEEN CIGS LIFTING AT SSI SLOWLY THIS EVENING...AND ANTICIPATE THAT BY ABOUT 14Z TUE THAT VFR WILL BEGIN TO PREVAIL THERE. IMPROVING TREND ALSO FOR JAX-GNV AREAS FOR LATE TUE MORNING AND THINK VFR WILL DEVELOP BY THE AFTN HOURS BUT ONLY MODERATE CONFIDENCE IN CRG PREVAILING AT VFR DUE TO ATLC OCEAN STRATOCU IN LOW LEVEL FLOW FROM THE NNE. ANY VSBY RESTRICTIONS LATE TONIGHT NEAR GNV DUE TO LIGHT/SHALLOW BR ARE EXPECTED TO REMAIN ABOVE MVFR ATTM. && .MARINE...NLY WINDS AND ROUGH SEAS IN SCA CATEGORY FOR TONIGHT. SEAS NEAR 5 FT CLOSE TO THE COAST PER NEARSHORE BUOYS RISE TO ABOUT 9-11 FT OFFSHORE PER SWAN GUIDANCE AND OBSERVATIONS. MODELS SUGGEST SLIGHT DOWNWARD TREND IN WIND SPEEDS BUT WIND/SEA STAY FIRMLY IN SCA THRESHOLD REST OF TONIGHT. LITTLE CHANGE IN THE HAZARDOUS BOATING CONDITIONS ON TUESDAY. RIP CURRENTS: HIGH RISK DUE TO ELY SWELLS AND ROUGH SURF ALONG WITH STRONG N TO S LONG SHORE CURRENT. && .PRELIMINARY POINT TEMPS/POPS... AMG 50 70 45 71 / 0 0 0 0 SSI 56 66 53 66 / 10 10 10 10 JAX 52 70 49 71 / 10 10 0 0 SGJ 57 67 54 68 / 10 10 10 10 GNV 50 72 47 72 / 0 0 0 0 OCF 51 74 47 72 / 10 10 10 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...HIGH RIP CURRENT RISK UNTIL 6 AM EST TUESDAY FOR DUVAL-FLAGLER- NASSAU-ST JOHNS. GA...HIGH RIP CURRENT RISK UNTIL 6 AM EST TUESDAY FOR COASTAL CAMDEN- COASTAL GLYNN. AM...SMALL CRAFT ADVISORY UNTIL 6 PM EST FRIDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ ZIBURA/SHASHY/MCALLISTER
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1237 AM EST SUN NOV 18 2012 .AVIATION... THE ISOLATED SHOWERS WILL CONTINUE TO AFFECT THE KPBI TAF SITE THROUGH TODAY...DUE TO THE FRONTAL BOUNDARY REMAINING NEARLY STATIONARY OVER THIS AREA. REST OF THE TAF SITES ACROSS SOUTH FLORIDA SHOULD REMAIN DRY TODAY. SO WILL KEEP A VCSH IN THE TAF SITE FOR KPBI. THE WINDS WILL ALSO BE LIGHT AND VARIABLE ACROSS THE EAST COAST TAF SITES EARLY THIS MORNING...BEFORE SWINGING TO A 10 TO 30 DEGREE DIRECTION WITH SPEEDS AROUND 10 MPH THROUGH 00Z MONDAY. AT KAPF TAF SITE...THE WIND SPEEDS WILL BE AROUND 10 MPH TODAY FROM THE NORTH TO NORTHEAST DIRECTION. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS TODAY AT ALL OF THE TAF SITES. && .AVIATION...54/BNB .PREV DISCUSSION... /ISSUED 1015 PM EST SAT NOV 17 2012/ UPDATE... NO MAJOR UPDATES TO THE PREVIOUS FORECAST ARE EXPECTED THIS EVENING. THE EVENING SURFACE ANALYSIS SHOWED A LINGERING WEAK TROUGH OR WHAT IS LEFT OF AN OLD FRONTAL BOUNDARY JUST EAST OF THE FLORIDA PENINSULA WITH LIGHT TO MODERATE NORTHEAST FLOW CONTINUING. ENHANCED LOW-LEVEL CONVERGENCE NEAR AND AROUND THIS SURFACE FEATURE COMBINED WITH BELOW AVERAGE MID/UPPER-LEVEL TEMPERATURES WILL MAINTAIN THE CHANCE FOR MAINLY ISOLATED SHOWERS OVER THE ADJACENT ATLANTIC WATERS AND COASTAL AREAS THROUGH THE OVERNIGHT HOURS. SIMILAR TO THE PAST FEW NIGHTS...INLAND FOG WILL BE POSSIBLE THROUGH THE OVERNIGHT HOURS ACROSS THE INTERIOR AREAS. THE LATEST SREF MODEL PROBABILITIES SUPPORT THIS AND INDICATE A GOOD PORTION OF THIS INTERIOR AREA AROUND AND SOUTH OF THE LAKE DIPPING INTO THE 1-3 MILE VISIBILITY RANGE BY DAYBREAK SUNDAY. 85/AG && PREV DISCUSSION... /ISSUED 644 PM EST SAT NOV 17 2012/ AVIATION... AS A STALLED FRONTAL BOUNDARY LINGERS JUST OFFSHORE THE ATLANTIC COAST...ISOLATED SHOWERS WILL REMAIN ACROSS THE AREA THROUGH THE NIGHT AND IS DEPICTED BY THE LATEST HRRR GUIDANCE. SHOWERS COULD BRIEFLY AFFECT ONE OR MORE EAST COAST SITES THROUGH THE EVENING WITH MVFR CONDITIONS BUT WOULD BE VERY BRIEF AND DECIDED NOT TO PREVAIL ANY SHRA MENTION. MID LEVEL DRYING EXPECTED TO PUSH INTO THE SOUTH FLORIDA PENINSULA FROM THE NORTH THROUGH THE LATTER HALF OF THE PERIOD. && PREV DISCUSSION... /ISSUED 246 PM EST SAT NOV 17 2012/ DISCUSSION... SHORT TERM...THE BASIC SYNOPTIC SETUP OVER THE AREA IS A NORTHWESTERLY FLOW OVER THE CWA AS HIGH PRESSURE TO THE NORTH SLOWLY PUSHES A LOW PRESSURE SYSTEM WELL TO THE SOUTHEAST EASTWARD. THERE IS A STALLED BOUNDARY THAT CONTINUES TO LAY ACROSS THE OFFSHORE WATERS IN THE ATLANTIC. THE HIGH, CENTERED OVER NEW ENGLAND, IS VERY SLOWLY CAUSING THE BOUNDARY TO DRIFT TO THE EAST AND HAS PUSHED MOST OF THE SHOWERS AWAY FROM THE CWA. THIS BOUNDARY WILL NOT GO FAR, HOWEVER, AS THERE IS NO REAL PUSH NORMAL TO THE BOUNDARY. RATHER, THE FLOW IS ALMOST PARALLEL TO THE BOUNDARY. SO, WITH STILL PLENTY OF MOISTURE REMAINING OVER THE MAINLAND, DAYTIME HEATING WILL CAUSE SOME ISOLATED SHOWERS TO DEVELOP. MODELS ARE INDICATING MOST OF ANY CONVECTION WILL BE LOCATED MAINLY OFF SHORE. THIS PATTERN WILL BE IN PLACE FOR THE REMAINDER OF THE WEEKEND. OVER THE NEXT COUPLE OF DAYS, THE LOW WILL SLOWLY MOVE TO THE NORTH AS THE HIGH PRESSURE SLIDES WELL TO THE NORTHEAST. THE LOW WILL THEN DEEPEN AND INTERACT WITH THE STALLED BOUNDARY, TURNING IT INTO A COLD FRONT. THIS COULD ALLOW FOR SOME SHOWERS OVER THE ATLANTIC TO DEVELOP, BUT STILL LOOK ISOLATED AT BEST THROUGH 12Z TUESDAY. ALSO, WITH THE LOW DEVELOPING NEXT WEEK, SOMEWHAT COOLER, DRIER AIR WILL TRY TO MAKE ITS WAY DOWN THE FLORIDA PENINSULA. WHILE THE TEMPERATURES WILL ONLY COOL A COUPLE OF DEGREES, THE DEW POINTS SHOULD DROP AROUND 5 DEGREES, ALLOWING THE AIR TO FEEL SOMEWHAT DRIER FOR THE BEGINNING OF THE WEEK. LONG TERM...TUESDAY THROUGH FRIDAY...DRY AND STABLE AIR OVER S FLA TUESDAY PRECLUDES PRECIPITATION EXCEPT FOR THE E COAST. BY WEDNESDAY THE APPROACHING UPPER TROUGH SHOVES A COLD FRONT TOWARD S FLA THAT MOVES THROUGH THE AREA WEDNESDAY WITH SOME SHOWER ACTIVITY. THURSDAY AND FRIDAY WILL BE DRY BUT COOLER. LOWS THURSDAY WILL RANGE FROM NEAR 50 W OF LAKE OKEECHOBEE TO THE LOWER 60S SE WITH SLIGHTLY WARMER TEMPERATURES FRIDAY MORNING. HIGHS WILL BE IN THE 70S THURSDAY AND FRIDAY. MARINE... NNE TO NE WINDS AT 10 TO 15 KTS THROUGH MONDAY THEN SHIFTING MORE NORTHERLY AND SLIGHTLY DECREASING TUESDAY BEFORE INCREASING FROM THE NW WEDNESDAY BEHIND THE FRONT WITH MARINE CONDITIONS DETERIORATING. SOME RISK OF RIP CURRENTS POSSIBLE E COAST TODAY...SUNDAY AND MONDAY. WATERSPOUTS POSSIBLE ATLC WATERS TODAY AS OFFSHORE FLOW CONVERGING WITH THE EASTERLY ATLC FLOW OFFSHORE. FIRE WEATHER... NO FIRE WEATHER CONCERNS ARE CURRENTLY ANTICIPATED. LOW PRESSURE TO THE SOUTH, WILL SLOWLY MOVE TO THE NORTH, WELL EAST OF THE BAHAMAS. THIS WILL ALLOW SLIGHTLY DRIER AIR TO MOVE IN NEXT WEEK, WITH SLIGHTLY COOLER TEMPERATURES AS WELL. WINDS, OVER THE NEXT FEW DAYS, WILL CONTINUE TO BE OUT OF THE NORTH NORTHEAST BETWEEN 5 AND 10 KTS. THEY WILL BECOME MORE NORTH TO NORTHWESTERLY BY MONDAY, STILL BETWEEN 5 AND 10KTS. AS FOR MINIMUM RH, EXPECT RH`S IN THE MID 50 PERCENT RANGE FOR THE WEEKEND, DROPPING INTO THE MID 40 TO LOW 50 PERCENT RANGE BEGINNING NEXT WEEK. RECOVERIES SHOULD CONTINUE TO BE GOOD EVERY NIGHT, REACHING INTO THE 90 PERCENT RANGE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 63 79 64 79 / 10 - - 10 FORT LAUDERDALE 65 79 65 80 / 10 10 - 10 MIAMI 65 79 65 79 / 10 - - 10 NAPLES 61 75 62 78 / 10 - - - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...15/JR AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
413 PM CST SUN NOV 18 2012 .DISCUSSION... 213 PM CST TONIGHT... ANTI-CYCLONIC FEATURE HAS BECOME STRETCHED OUT WITH A CENTER OVER SOUTHEAST QUEBEC AND CONTINUES TO PROVIDE A MAIN INFLUENCE ACROSS THE OHIO VALLEY/MID-MISSISSIPPI VALLEY. TO THE WEST OF THIS INFLUENCE ACROSS PORTIONS OF THE UPPER MIDWEST/CENTRAL PLAINS...THE PRESSURE GRADIENT IS TIGHTER AND RESULTING IN OCCASIONALLY GUSTY SOUTH WINDS IN THOSE AREAS. VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CHANNEL OF CIRRUS CLOUDS FROM NORTHERN IL STRETCHING WEST THROUGH IOWA...THEN A MORE EXPANSIVE AREA OF CIRRUS CLOUDS ACROSS THE SOUTHERN PLAINS INTO THE SOUTHERN ROCKIES. THE SOUTHERN ROCKIES IS THE AREA THAT GUIDANCE HAS BEEN FOCUSED ON FOR THE DEVELOPMENT OF A WEAK WAVE THAT WILL SLIDE ALONG THE FRONTAL BOUNDARY AND OVERSPREAD CLOUDS AND LGT PRECIP TO PORTIONS OF THE GREAT LAKES MON NGT. CLOUD COVER WILL STEADILY SLIDE OVERHEAD THIS EVENING/OVERNIGHT...WITH A FEW POCKETS OF CLEARING. DEEPER MOISTURE WILL REMAIN WEST OF THE CWFA THROUGH THE OVERNIGHT...MAINLY OVER IA/MO/KS/OK. WITH POTENTIALLY HIGH CLOUDS OVERHEAD SFC TEMPS SHOULD BE ABLE TO RADIATE INTO THE MID/UPR 30S ACROSS THE REGION. SFC WINDS SHOULD CONTINUE OVERNIGHT AROUND 10 MPH OR LESS...HOWEVER SHOULD BE JUST ENOUGH TO PREVENT LARGE SCALE FOG DEVELOPMENT. A FEW PROTECTED AREAS AND LOCATIONS CLOSEST TO STREAMS...MAY SEE PATCHY FOG DEVELOP. THE OTHER AREAS THAT COULD SEE PATCHY FOG MAY BE THE FAR NORTHEAST CORNER OF NORTHEAST IL...WITH A WEAK ONSHORE FLOW AND MARINE MOISTURE BLEEDING INLAND A FEW MILES. CONFIDENCE...HIGH. MONDAY THROUGH TUESDAY... ANTI-CYCLONIC FLOW IS PROGGED TO BE THE MAIN FEATURE FOR EARLY WEEK...HOWEVER A WEAK FRONTAL BOUNDARY IS PROGGED TO PUSH EAST ACROSS THE MISSISSIPPI VALLEY INTO THE GREAT LAKES MONDAY NIGHT/EARLY TUESDAY. GUIDANCE HAS CONTINUED TO HINT THAT SOME MOISTURE WILL ACCOMPANY THIS BOUNDARY...ALTHOUGH LOOKING UPSTREAM AT CURRENT CONDITIONS IT APPEARS THE SCENARIO OF LIGHT PRECIP IS LOW FOR MONDAY NIGHT/EARLY TUE. ANOTHER POTENTIAL LIMITING FACTOR IS THAT THE EXPECTED DOWNSTREAM RIDGE MAY CONTINUE TO HOLD WITH DIFFLUENT FLOW IN THE MID-LVLS...WHICH WOULD AID IN DRYING THE MOISTURE AT THE MID-LVLS. LLVL FLOW MAY BACK SLIGHTLY TO THE SOUTHEAST...WHICH COULD ALSO AID IN MOISTURE AVAILABILITY. FORCING DOES NOT APPEAR TO BE VERY POTENT EITHER. MANY PLUMES SUGGEST A DRY MON NGT/EARLY TUE AS WELL ACROSS THE CWFA. BASED ON THESE AFOREMENTIONED ELEMENTS...HAVE OPTED TO REMOVE MENTION OF PRECIP ACROSS THE CWFA FOR MON NGT/EARLY TUE...AND ADJUSTED ANY PRECIP TO LOCATIONS FURTHER NORTH ACROSS WISC/LAKE MICHIGAN/LOWER MICHIGAN. IF PRECIP DOES DEVELOP...IT APPEARS IT MAY END UP BEING SPRINKLES. OVERALL EXPECT JUST CLOUDS TO BE ON THE INCREASE FROM THIS SYSTEM. TEMPS BOTH DAYS WILL CONTINUE TO BE MILD WITH A THERMAL RIDGE OF 5 TO 7 DEG C MONDAY...AND 6 TO 8 DEG C TUESDAY. WITH OPTIMAL CONDS EXPECTED BOTH DAYS...TEMPS SHOULD EASILY WARM INTO THE MID/UPR 50S. FOR LOCATIONS ALONG AND SOUTH OF I-80 TEMPS COULD TOUCH 60 DEGREES TUESDAY AFTERNOON. SEVERAL 2M TEMP PLUMES FOR THIS PERIOD ALSO SUPPORT THIS MAX TEMP FORECAST. OVERNIGHT LOWS WILL ALSO BE MILD...UPR 30S/LOW 40S. CONFIDENCE...HIGH. PRECIP CONFIDENCE...MEDIUM/HIGH. WEDNESDAY... ONE OF THE BUSIEST TRAVEL DAYS OF THE YEAR...AND IT APPEARS MOTHER NATURE WILL COOPERATE AND PRODUCE OPTIMAL TRAVEL CONDITIONS FOR NORTHERN IL/NORTHWEST IN. ANTI-CYCLONIC FLOW WILL PUSH BACK INTO THE REGION AND ERODE THE CLOUDS TUE NGT/EARLY WED...WITH COULD ALLOW TEMPS EARLY WED BEFORE SUNRISE TO DIP INTO THE LOW 30S. THEN A LARGE DIURNAL CURVE IS EXPECTED FOR WED AFTERNOON. 850MB THERMAL RIDGE OF 7 TO 9 DEG C IS PROGGED TO SLIDE OVERHEAD FROM THE WEST/SOUTHWEST...WITH LLVL FLOW TURNING SOUTH/SOUTHWEST. THE BEST PRESSURE GRADIENT AND ADVECTION APPEARS TO BE DISPLACED TO THE NORTHWEST/WEST OF THE CWFA...HOWEVER IT APPEARS TEMPS COULD EASILY WARM TO 60 DEG ACROSS THE AREA. FOR AREAS ALONG AND WEST OF A ROCKFORD/KANKAKEE LINE...TEMPS MAY PUSH TO 61 TO 63 DEG. CONFIDENCE...HIGH. THANKSGIVING THROUGH SATURDAY... THE ANOMALOUS WARM/DRY PATTERN THAT HAS DOMINATED MUCH OF THE REGION FOR THE PAST SEVERAL DAYS...MAY BE TRANSITIONING INTO A MORE ACTIVE PATTERN. ABOVE NORMAL 500MB HEIGHTS WILL PERSIST THROUGH THUR...THEN STEADILY WEAKEN INTO A SEMI-ZONAL FLOW AND POSSIBLY A TROUGH DIGGING INTO THE UPPER MIDWEST/CENTRAL ROCKIES DEVELOPS. GUIDANCE BECOMES RATHER NOISY IN THE EXTENDED PERIODS FROM FRI-SAT...WHICH IS INDICATED BY THE ENVELOPE OF SOLUTIONS THAT THE ENSEMBLES PROG AS WELL AS OPERATIONAL GFS/ECMWF. THE FIRST FEW PERIODS WILL CONTINUE TO BE MILD WITH TEMPS NEAR 60 TO POSSIBLY THE LOW 60S IN THE AFTERNOON FOR THANKSGIVING...HOWEVER THIS WILL CHANGE FOR FRI/SAT. 500MB TROUGH CONTINUES TO BE PROGGED BY OPERATIONAL SOLUTIONS AND ANTI-CYCLONIC FLOW WILL DEPART TO THE SOUTHEAST. THIS WILL AID IN A STRENGTHENING SOUTHWEST FLOW THUR NGT/FRI AS A FRONTAL BOUNDARY BEGINS TO APPROACH THE REGION. 850MB THERMAL TROUGH OF -2 TO -5 DEG C SHOULD ARRIVE ACROSS THE REGION MIDDAY FRI...THUS TEMPS FRI MAY STRUGGLE TO WARM WITH POSSIBLY THE WARMEST TEMPS FOR THE DAY OCCURRING IN THE MORNING. 500MB SPEED MAX PIVOTS EAST ACROSS THE UPPER MIDWEST/NORTHERN GREAT LAKES...HOWEVER APPEARS TO BE MAINLY MOISTURE STARVED. AT THIS POINT HAVE CONTINUED TO MENTION CHC POPS...AND TEMPS SHOULD BE COOL ENOUGH TO PRODUCE A POSSIBLE RA/SN MIX HOWEVER MOISTURE RAPIDLY PIVOTS NORTHEAST BY FRI AFTN/EVE THAT THIS WOULD BE RESTRICTED TO THE LAKE ENVIRONMENT AND LOWER MICHIGAN. THEN ANTI-CYCLONIC FLOW IS PROGGED TO BUILD BACK INTO THE MIDWEST/GREAT LAKES REGION FOR THE REMAINDER OF THE WEEKEND AND PROVIDE DRY WEATHER. IN ADDITION THE LONGER TERM MODELS CONTINUE TO HINT THAT TEMPS MAY YET AGAIN PUSH BACK ABOVE NORMAL FOR THE SECOND HALF OF THE WEEKEND AND POSSIBLY CONTINUE INTO EARLY THE FOLLOWING WEEK. CONFIDENCE...HIGH. BEACHLER && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECAST HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * VARIABLE SE-SSE WINDS THROUGH EARLY EVENING BECOMING STEADIER SOUTHEAST. MDB //DISCUSSION...UPDATED 22Z... LAKE INFLUENCE SEEMS TO BE WEAKENING FOR AREAS EAST AND NORTH OF ORD...POTENTIALLY DUE TO INCREASING HIGH LEVEL CLOUD SHIELD. AREAS FROM UGN TO PWK THAT HAD SEEN A LARGER EAST COMPONENT TO THE SOUTHERLY WIND HAVE TURNED MORE SOUTHEASTERLY FOR THE MOST PART...WITH AREAS RIGHT ALONG THE ILLINOIS SHORE DOING SIMILAR. SO IT APPEARS THAT A LARGER SOUTH WIND COMPONENT WILL PREVAIL ACROSS THE CHI AREA TERMINALS WITH SOME VARIABILITY BETWEEN SE AND SSE AT ORD/MDW FOR THE NEXT FEW HOURS. MDB FROM 18Z... LATEST HI RES RUC AND HRR MODEL OUTPUT CONTINUE TO SUGGEST A WEAK LAKE BREEZE...SUCH AS OCCURRED FRI AND SAT...IS TO DEVELOP AND EVENTUALLY MOVE INLAND TO MDW AND ORD VICINITY 21-22Z TIME-FRAME. RESULT IS THAT 5-10 KT SSE WINDS BACK A BIT TO SE-ESE FOR THE LATE AFTERNOON. MARINE OBS SITES CURRENTLY SHOW A SE WIND DIRECTION AT WAUKEGAN AND BURNHAM HARBORS WITH MESONET OBS INDICATING LIGHT VARIABLE WINDS FROM JUST ASHORE TO A COUPLE MILES INLAND SUGGESTING THE WEAK BOUNDARY IS ALONG THE SHORE AND LITTLE RESISTANCE TO MOVING GRADUALLY INLAND AS CURRENT SMALL TEMPERATURE DIFFERENTIAL BETWEEN LAND AND WATER CONTINUES TO INCREASE. WITH LOSS OF HEATING TOWARDS DUSK AND DISSIPATION OF LAKE BREEZE EARLY IN THE EVENING WINDS TO RETURN TO SSE-S. SPEEDS TO BE LESS THAN 10 KT AS STRONGER SSW FLOW AHEAD OF AN APPROACHING COLD FRONT/SURFACE TROUGH MOVING EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WILL BE DECOUPLED FROM THE SURFACE DURING THE NIGHT. AFTER SUNRISE MONDAY MORNING STRONG...SHALLOW INVERSION WILL BEGIN TO BE ERODED THOUGH WINDS AT TOP OF BOUNDARY LAYER DURING LATER MORNING AND AFTERNOON ARE ONLY 14-17KT. EXPECT SOUTHERLY SURFACE WINDS TO AVERAGE 8-10 KT AFTER SOME SURFACE HEATING AND MIXING WITH POSSIBLE OCCASIONAL GUSTS OF 14-17KT. EXPECT VFR CONDITIONS THROUGHOUT THE VALID TAFOR PERIOD WITH ONLY SCT-BKN MID AND HIGH LEVEL CLOUDS. TRS //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE IN VARIABLE WIND DIRECTION THROUGH EARLY EVENING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 225 PM CST A LARGE RIDGE OF HIGH PRESSURE EXTENDS FROM NOVA SCOTIA TO THE LOWER MISSISSIPPI VALLEY.. THE RIDGE IS EXPECTED TO ONLY DRIFT VERY SLOWLY EAST OVER THE NEXT SEVERAL DAYS WHILE GRADUALLY WEAKENING. A TROUGH OF LOW PRESSURE WILL MOVE INTO THE DAKOTAS TODAY...THEN INTO THE WESTERN GREAT LAKES MONDAY NIGHT AS IT WEAKENS SLIGHTLY. THIS WILL KEEP GENERALLY SOUTHERLY WINDS OVER THE LAKE UNTIL EARLY NEXT WEEK. AS THE TROUGH FURTHER WEAKENS TUESDAY NIGHT AND AN ASSOCIATED WEAK COLD FRONT CROSSES LAKE MICHIGAN... WINDS WILL SHIFT TO NORTHWESTERLY. HOWEVER...NO INCREASE IN WINDS IS LIKELY AS A WEAK RIDGE OF HIGH PRESSURE WILL IMMEDIATELY FILL IN BEHIND THE FRONT AND THERE IS NO SIGNIFICANTLY COLD AIR BEHIND THE FRONT. ANOTHER LOW IS FORECAST TO DEVELOP OVER MONTANA ON WEDNESDAY AND QUICKLY TRACK EASTWARD TO NEAR LAKE SUPERIOR BY THURSDAY EVENING. THE LOW WILL THEN TURN NORTHEAST TOWARD SOUTHERN JAMES BAY...DRAGGING A COLD FRONT ACROSS LAKE MICHIGAN LATE THURSDAY NIGHT OR FRIDAY MORNING. THIS FRONT IS EXPECTED TO BE MUCH STRONGER THAN THE PREVIOUS FRONT...BRINGING IN A MUCH COLDER INFLUX OF COLDER AIR...AND WILL BRING STRENGTHENING NORTHWESTERLY WINDS TO THE LAKE, KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
225 PM CST SUN NOV 18 2012 .DISCUSSION... 213 PM CST TONIGHT... ANTI-CYCLONIC FEATURE HAS BECOME STRETCHED OUT WITH A CENTER OVER SOUTHEAST QUEBEC AND CONTINUES TO PROVIDE A MAIN INFLUENCE ACROSS THE OHIO VALLEY/MID-MISSISSIPPI VALLEY. TO THE WEST OF THIS INFLUENCE ACROSS PORTIONS OF THE UPPER MIDWEST/CENTRAL PLAINS...THE PRESSURE GRADIENT IS TIGHTER AND RESULTING IN OCCASIONALLY GUSTY SOUTH WINDS IN THOSE AREAS. VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CHANNEL OF CIRRUS CLOUDS FROM NORTHERN IL STRETCHING WEST THROUGH IOWA...THEN A MORE EXPANSIVE AREA OF CIRRUS CLOUDS ACROSS THE SOUTHERN PLAINS INTO THE SOUTHERN ROCKIES. THE SOUTHERN ROCKIES IS THE AREA THAT GUIDANCE HAS BEEN FOCUSED ON FOR THE DEVELOPMENT OF A WEAK WAVE THAT WILL SLIDE ALONG THE FRONTAL BOUNDARY AND OVERSPREAD CLOUDS AND LGT PRECIP TO PORTIONS OF THE GREAT LAKES MON NGT. CLOUD COVER WILL STEADILY SLIDE OVERHEAD THIS EVENING/OVERNIGHT...WITH A FEW POCKETS OF CLEARING. DEEPER MOISTURE WILL REMAIN WEST OF THE CWFA THROUGH THE OVERNIGHT...MAINLY OVER IA/MO/KS/OK. WITH POTENTIALLY HIGH CLOUDS OVERHEAD SFC TEMPS SHOULD BE ABLE TO RADIATE INTO THE MID/UPR 30S ACROSS THE REGION. SFC WINDS SHOULD CONTINUE OVERNIGHT AROUND 10 MPH OR LESS...HOWEVER SHOULD BE JUST ENOUGH TO PREVENT LARGE SCALE FOG DEVELOPMENT. A FEW PROTECTED AREAS AND LOCATIONS CLOSEST TO STREAMS...MAY SEE PATCHY FOG DEVELOP. THE OTHER AREAS THAT COULD SEE PATCHY FOG MAY BE THE FAR NORTHEAST CORNER OF NORTHEAST IL...WITH A WEAK ONSHORE FLOW AND MARINE MOISTURE BLEEDING INLAND A FEW MILES. CONFIDENCE...HIGH. MONDAY THROUGH TUESDAY... ANTI-CYCLONIC FLOW IS PROGGED TO BE THE MAIN FEATURE FOR EARLY WEEK...HOWEVER A WEAK FRONTAL BOUNDARY IS PROGGED TO PUSH EAST ACROSS THE MISSISSIPPI VALLEY INTO THE GREAT LAKES MONDAY NIGHT/EARLY TUESDAY. GUIDANCE HAS CONTINUED TO HINT THAT SOME MOISTURE WILL ACCOMPANY THIS BOUNDARY...ALTHOUGH LOOKING UPSTREAM AT CURRENT CONDITIONS IT APPEARS THE SCENARIO OF LIGHT PRECIP IS LOW FOR MONDAY NIGHT/EARLY TUE. ANOTHER POTENTIAL LIMITING FACTOR IS THAT THE EXPECTED DOWNSTREAM RIDGE MAY CONTINUE TO HOLD WITH DIFFLUENT FLOW IN THE MID-LVLS...WHICH WOULD AID IN DRYING THE MOISTURE AT THE MID-LVLS. LLVL FLOW MAY BACK SLIGHTLY TO THE SOUTHEAST...WHICH COULD ALSO AID IN MOISTURE AVAILABILITY. FORCING DOES NOT APPEAR TO BE VERY POTENT EITHER. MANY PLUMES SUGGEST A DRY MON NGT/EARLY TUE AS WELL ACROSS THE CWFA. BASED ON THESE AFOREMENTIONED ELEMENTS...HAVE OPTED TO REMOVE MENTION OF PRECIP ACROSS THE CWFA FOR MON NGT/EARLY TUE...AND ADJUSTED ANY PRECIP TO LOCATIONS FURTHER NORTH ACROSS WISC/LAKE MICHIGAN/LOWER MICHIGAN. IF PRECIP DOES DEVELOP...IT APPEARS IT MAY END UP BEING SPRINKLES. OVERALL EXPECT JUST CLOUDS TO BE ON THE INCREASE FROM THIS SYSTEM. TEMPS BOTH DAYS WILL CONTINUE TO BE MILD WITH A THERMAL RIDGE OF 5 TO 7 DEG C MONDAY...AND 6 TO 8 DEG C TUESDAY. WITH OPTIMAL CONDS EXPECTED BOTH DAYS...TEMPS SHOULD EASILY WARM INTO THE MID/UPR 50S. FOR LOCATIONS ALONG AND SOUTH OF I-80 TEMPS COULD TOUCH 60 DEGREES TUESDAY AFTERNOON. SEVERAL 2M TEMP PLUMES FOR THIS PERIOD ALSO SUPPORT THIS MAX TEMP FORECAST. OVERNIGHT LOWS WILL ALSO BE MILD...UPR 30S/LOW 40S. CONFIDENCE...HIGH. PRECIP CONFIDENCE...MEDIUM/HIGH. WEDNESDAY... ONE OF THE BUSIEST TRAVEL DAYS OF THE YEAR...AND IT APPEARS MOTHER NATURE WILL COOPERATE AND PRODUCE OPTIMAL TRAVEL CONDITIONS FOR NORTHERN IL/NORTHWEST IN. ANTI-CYCLONIC FLOW WILL PUSH BACK INTO THE REGION AND ERODE THE CLOUDS TUE NGT/EARLY WED...WITH COULD ALLOW TEMPS EARLY WED BEFORE SUNRISE TO DIP INTO THE LOW 30S. THEN A LARGE DIURNAL CURVE IS EXPECTED FOR WED AFTERNOON. 850MB THERMAL RIDGE OF 7 TO 9 DEG C IS PROGGED TO SLIDE OVERHEAD FROM THE WEST/SOUTHWEST...WITH LLVL FLOW TURNING SOUTH/SOUTHWEST. THE BEST PRESSURE GRADIENT AND ADVECTION APPEARS TO BE DISPLACED TO THE NORTHWEST/WEST OF THE CWFA...HOWEVER IT APPEARS TEMPS COULD EASILY WARM TO 60 DEG ACROSS THE AREA. FOR AREAS ALONG AND WEST OF A ROCKFORD/KANKAKEE LINE...TEMPS MAY PUSH TO 61 TO 63 DEG. CONFIDENCE...HIGH. THANKSGIVING THROUGH SATURDAY... THE ANOMALOUS WARM/DRY PATTERN THAT HAS DOMINATED MUCH OF THE REGION FOR THE PAST SEVERAL DAYS...MAY BE TRANSITIONING INTO A MORE ACTIVE PATTERN. ABOVE NORMAL 500MB HEIGHTS WILL PERSIST THROUGH THUR...THEN STEADILY WEAKEN INTO A SEMI-ZONAL FLOW AND POSSIBLY A TROUGH DIGGING INTO THE UPPER MIDWEST/CENTRAL ROCKIES DEVELOPS. GUIDANCE BECOMES RATHER NOISY IN THE EXTENDED PERIODS FROM FRI-SAT...WHICH IS INDICATED BY THE ENVELOPE OF SOLUTIONS THAT THE ENSEMBLES PROG AS WELL AS OPERATIONAL GFS/ECMWF. THE FIRST FEW PERIODS WILL CONTINUE TO BE MILD WITH TEMPS NEAR 60 TO POSSIBLY THE LOW 60S IN THE AFTERNOON FOR THANKSGIVING...HOWEVER THIS WILL CHANGE FOR FRI/SAT. 500MB TROUGH CONTINUES TO BE PROGGED BY OPERATIONAL SOLUTIONS AND ANTI-CYCLONIC FLOW WILL DEPART TO THE SOUTHEAST. THIS WILL AID IN A STRENGTHENING SOUTHWEST FLOW THUR NGT/FRI AS A FRONTAL BOUNDARY BEGINS TO APPROACH THE REGION. 850MB THERMAL TROUGH OF -2 TO -5 DEG C SHOULD ARRIVE ACROSS THE REGION MIDDAY FRI...THUS TEMPS FRI MAY STRUGGLE TO WARM WITH POSSIBLY THE WARMEST TEMPS FOR THE DAY OCCURRING IN THE MORNING. 500MB SPEED MAX PIVOTS EAST ACROSS THE UPPER MIDWEST/NORTHERN GREAT LAKES...HOWEVER APPEARS TO BE MAINLY MOISTURE STARVED. AT THIS POINT HAVE CONTINUED TO MENTION CHC POPS...AND TEMPS SHOULD BE COOL ENOUGH TO PRODUCE A POSSIBLE RA/SN MIX HOWEVER MOISTURE RAPIDLY PIVOTS NORTHEAST BY FRI AFTN/EVE THAT THIS WOULD BE RESTRICTED TO THE LAKE ENVIRONMENT AND LOWER MICHIGAN. THEN ANTI-CYCLONIC FLOW IS PROGGED TO BUILD BACK INTO THE MIDWEST/GREAT LAKES REGION FOR THE REMAINDER OF THE WEEKEND AND PROVIDE DRY WEATHER. IN ADDITION THE LONGER TERM MODELS CONTINUE TO HINT THAT TEMPS MAY YET AGAIN PUSH BACK ABOVE NORMAL FOR THE SECOND HALF OF THE WEEKEND AND POSSIBLY CONTINUE INTO EARLY THE FOLLOWING WEEK. CONFIDENCE...HIGH. BEACHLER && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEAK LAKE BREEZE MOVING INLAND TO ORD VC 22-23Z TIME-FRAME BACKING WINDS SOMEWHAT FROM SSE TO SE FOR A PERIOD LATE AFTERNOON-EARLY EVENING. TRS //DISCUSSION...UPDATED 18Z... LATEST HI RES RUC AND HRR MODEL OUTPUT CONTINUE TO SUGGEST A WEAK LAKE BREEZE...SUCH AS OCCURRED FRI AND SAT...IS TO DEVELOP AND EVENTUALLY MOVE INLAND TO MDW AND ORD VICINITY 21-22Z TIME-FRAME. RESULT IS THAT 5-10 KT SSE WINDS BACK A BIT TO SE-ESE FOR THE LATE AFTERNOON. MARINE OBS SITES CURRENTLY SHOW A SE WIND DIRECTION AT WAUKEGAN AND BURNHAM HARBORS WITH MESONET OBS INDICATING LIGHT VARIABLE WINDS FROM JUST ASHORE TO A COUPLE MILES INLAND SUGGESTING THE WEAK BOUNDARY IS ALONG THE SHORE AND LITTLE RESISTANCE TO MOVING GRADUALLY INLAND AS CURRENT SMALL TEMPERATURE DIFFERENTIAL BETWEEN LAND AND WATER CONTINUES TO INCREASE. WITH LOSS OF HEATING TOWARDS DUSK AND DISSIPATION OF LAKE BREEZE EARLY IN THE EVENING WINDS TO RETURN TO SSE-S. SPEEDS TO BE LESS THAN 10 KT AS STRONGER SSW FLOW AHEAD OF AN APPROACHING COLD FRONT/SURFACE TROUGH MOVING EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WILL BE DECOUPLED FROM THE SURFACE DURING THE NIGHT. AFTER SUNRISE MONDAY MORNING STRONG...SHALLOW INVERSION WILL BEGIN TO BE ERODED THOUGH WINDS AT TOP OF BOUNDARY LAYER DURING LATER MORNING AND AFTERNOON ARE ONLY 14-17KT. EXPECT SOUTHERLY SURFACE WINDS TO AVERAGE 8-10 KT AFTER SOME SURFACE HEATING AND MIXING WITH POSSIBLE OCCASIONAL GUSTS OF 14-17KT. EXPECT VFR CONDITIONS THROUGHOUT THE VALID TAFOR PERIOD WITH ONLY SCT-BKN MID AND HIGH LEVEL CLOUDS. TRS //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE IN ORD WIND VEERING FM SSE TO SE DURING MID- LATE AFTERNOON DUE TO WEAK LAKE BREEZE MOVING INLAND ACROSS EXTREME NORTHEAST IL. * HIGH CONFIDENCE REMAINDER OF FCST. TRS //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 225 PM CST A LARGE RIDGE OF HIGH PRESSURE EXTENDS FROM NOVA SCOTIA TO THE LOWER MISSISSIPPI VALLEY.. THE RIDGE IS EXPECTED TO ONLY DRIFT VERY SLOWLY EAST OVER THE NEXT SEVERAL DAYS WHILE GRADUALLY WEAKENING. A TROUGH OF LOW PRESSURE WILL MOVE INTO THE DAKOTAS TODAY...THEN INTO THE WESTERN GREAT LAKES MONDAY NIGHT AS IT WEAKENS SLIGHTLY. THIS WILL KEEP GENERALLY SOUTHERLY WINDS OVER THE LAKE UNTIL EARLY NEXT WEEK. AS THE TROUGH FURTHER WEAKENS TUESDAY NIGHT AND AN ASSOCIATED WEAK COLD FRONT CROSSES LAKE MICHIGAN... WINDS WILL SHIFT TO NORTHWESTERLY. HOWEVER...NO INCREASE IN WINDS IS LIKELY AS A WEAK RIDGE OF HIGH PRESSURE WILL IMMEDIATELY FILL IN BEHIND THE FRONT AND THERE IS NO SIGNIFICANTLY COLD AIR BEHIND THE FRONT. ANOTHER LOW IS FORECAST TO DEVELOP OVER MONTANA ON WEDNESDAY AND QUICKLY TRACK EASTWARD TO NEAR LAKE SUPERIOR BY THURSDAY EVENING. THE LOW WILL THEN TURN NORTHEAST TOWARD SOUTHERN JAMES BAY...DRAGGING A COLD FRONT ACROSS LAKE MICHIGAN LATE THURSDAY NIGHT OR FRIDAY MORNING. THIS FRONT IS EXPECTED TO BE MUCH STRONGER THAN THE PREVIOUS FRONT...BRINGING IN A MUCH COLDER INFLUX OF COLDER AIR...AND WILL BRING STRENGTHENING NORTHWESTERLY WINDS TO THE LAKE, KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
214 PM CST SUN NOV 18 2012 .DISCUSSION... 213 PM CST TONIGHT... ANTI-CYCLONIC FEATURE HAS BECOME STRETCHED OUT WITH A CENTER OVER SOUTHEAST QUEBEC AND CONTINUES TO PROVIDE A MAIN INFLUENCE ACROSS THE OHIO VALLEY/MID-MISSISSIPPI VALLEY. TO THE WEST OF THIS INFLUENCE ACROSS PORTIONS OF THE UPPER MIDWEST/CENTRAL PLAINS...THE PRESSURE GRADIENT IS TIGHTER AND RESULTING IN OCCASIONALLY GUSTY SOUTH WINDS IN THOSE AREAS. VISIBLE IMAGERY EARLY THIS AFTERNOON DEPICTS A CHANNEL OF CIRRUS CLOUDS FROM NORTHERN IL STRETCHING WEST THROUGH IOWA...THEN A MORE EXPANSIVE AREA OF CIRRUS CLOUDS ACROSS THE SOUTHERN PLAINS INTO THE SOUTHERN ROCKIES. THE SOUTHERN ROCKIES IS THE AREA THAT GUIDANCE HAS BEEN FOCUSED ON FOR THE DEVELOPMENT OF A WEAK WAVE THAT WILL SLIDE ALONG THE FRONTAL BOUNDARY AND OVERSPREAD CLOUDS AND LGT PRECIP TO PORTIONS OF THE GREAT LAKES MON NGT. CLOUD COVER WILL STEADILY SLIDE OVERHEAD THIS EVENING/OVERNIGHT...WITH A FEW POCKETS OF CLEARING. DEEPER MOISTURE WILL REMAIN WEST OF THE CWFA THROUGH THE OVERNIGHT...MAINLY OVER IA/MO/KS/OK. WITH POTENTIALLY HIGH CLOUDS OVERHEAD SFC TEMPS SHOULD BE ABLE TO RADIATE INTO THE MID/UPR 30S ACROSS THE REGION. SFC WINDS SHOULD CONTINUE OVERNIGHT AROUND 10 MPH OR LESS...HOWEVER SHOULD BE JUST ENOUGH TO PREVENT LARGE SCALE FOG DEVELOPMENT. A FEW PROTECTED AREAS AND LOCATIONS CLOSEST TO STREAMS...MAY SEE PATCHY FOG DEVELOP. THE OTHER AREAS THAT COULD SEE PATCHY FOG MAY BE THE FAR NORTHEAST CORNER OF NORTHEAST IL...WITH A WEAK ONSHORE FLOW AND MARINE MOISTURE BLEEDING INLAND A FEW MILES. CONFIDENCE...HIGH. MONDAY THROUGH TUESDAY... ANTI-CYCLONIC FLOW IS PROGGED TO BE THE MAIN FEATURE FOR EARLY WEEK...HOWEVER A WEAK FRONTAL BOUNDARY IS PROGGED TO PUSH EAST ACROSS THE MISSISSIPPI VALLEY INTO THE GREAT LAKES MONDAY NIGHT/EARLY TUESDAY. GUIDANCE HAS CONTINUED TO HINT THAT SOME MOISTURE WILL ACCOMPANY THIS BOUNDARY...ALTHOUGH LOOKING UPSTREAM AT CURRENT CONDITIONS IT APPEARS THE SCENARIO OF LIGHT PRECIP IS LOW FOR MONDAY NIGHT/EARLY TUE. ANOTHER POTENTIAL LIMITING FACTOR IS THAT THE EXPECTED DOWNSTREAM RIDGE MAY CONTINUE TO HOLD WITH DIFFLUENT FLOW IN THE MID-LVLS...WHICH WOULD AID IN DRYING THE MOISTURE AT THE MID-LVLS. LLVL FLOW MAY BACK SLIGHTLY TO THE SOUTHEAST...WHICH COULD ALSO AID IN MOISTURE AVAILABILITY. FORCING DOES NOT APPEAR TO BE VERY POTENT EITHER. MANY PLUMES SUGGEST A DRY MON NGT/EARLY TUE AS WELL ACROSS THE CWFA. BASED ON THESE AFOREMENTIONED ELEMENTS...HAVE OPTED TO REMOVE MENTION OF PRECIP ACROSS THE CWFA FOR MON NGT/EARLY TUE...AND ADJUSTED ANY PRECIP TO LOCATIONS FURTHER NORTH ACROSS WISC/LAKE MICHIGAN/LOWER MICHIGAN. IF PRECIP DOES DEVELOP...IT APPEARS IT MAY END UP BEING SPRINKLES. OVERALL EXPECT JUST CLOUDS TO BE ON THE INCREASE FROM THIS SYSTEM. TEMPS BOTH DAYS WILL CONTINUE TO BE MILD WITH A THERMAL RIDGE OF 5 TO 7 DEG C MONDAY...AND 6 TO 8 DEG C TUESDAY. WITH OPTIMAL CONDS EXPECTED BOTH DAYS...TEMPS SHOULD EASILY WARM INTO THE MID/UPR 50S. FOR LOCATIONS ALONG AND SOUTH OF I-80 TEMPS COULD TOUCH 60 DEGREES TUESDAY AFTERNOON. SEVERAL 2M TEMP PLUMES FOR THIS PERIOD ALSO SUPPORT THIS MAX TEMP FORECAST. OVERNIGHT LOWS WILL ALSO BE MILD...UPR 30S/LOW 40S. CONFIDENCE...HIGH. PRECIP CONFIDENCE...MEDIUM/HIGH. WEDNESDAY... ONE OF THE BUSIEST TRAVEL DAYS OF THE YEAR...AND IT APPEARS MOTHER NATURE WILL COOPERATE AND PRODUCE OPTIMAL TRAVEL CONDITIONS FOR NORTHERN IL/NORTHWEST IN. ANTI-CYCLONIC FLOW WILL PUSH BACK INTO THE REGION AND ERODE THE CLOUDS TUE NGT/EARLY WED...WITH COULD ALLOW TEMPS EARLY WED BEFORE SUNRISE TO DIP INTO THE LOW 30S. THEN A LARGE DIURNAL CURVE IS EXPECTED FOR WED AFTERNOON. 850MB THERMAL RIDGE OF 7 TO 9 DEG C IS PROGGED TO SLIDE OVERHEAD FROM THE WEST/SOUTHWEST...WITH LLVL FLOW TURNING SOUTH/SOUTHWEST. THE BEST PRESSURE GRADIENT AND ADVECTION APPEARS TO BE DISPLACED TO THE NORTHWEST/WEST OF THE CWFA...HOWEVER IT APPEARS TEMPS COULD EASILY WARM TO 60 DEG ACROSS THE AREA. FOR AREAS ALONG AND WEST OF A ROCKFORD/KANKAKEE LINE...TEMPS MAY PUSH TO 61 TO 63 DEG. CONFIDENCE...HIGH. THANKSGIVING THROUGH SATURDAY... THE ANOMALOUS WARM/DRY PATTERN THAT HAS DOMINATED MUCH OF THE REGION FOR THE PAST SEVERAL DAYS...MAY BE TRANSITIONING INTO A MORE ACTIVE PATTERN. ABOVE NORMAL 500MB HEIGHTS WILL PERSIST THROUGH THUR...THEN STEADILY WEAKEN INTO A SEMI-ZONAL FLOW AND POSSIBLY A TROUGH DIGGING INTO THE UPPER MIDWEST/CENTRAL ROCKIES DEVELOPS. GUIDANCE BECOMES RATHER NOISY IN THE EXTENDED PERIODS FROM FRI-SAT...WHICH IS INDICATED BY THE ENVELOPE OF SOLUTIONS THAT THE ENSEMBLES PROG AS WELL AS OPERATIONAL GFS/ECMWF. THE FIRST FEW PERIODS WILL CONTINUE TO BE MILD WITH TEMPS NEAR 60 TO POSSIBLY THE LOW 60S IN THE AFTERNOON FOR THANKSGIVING...HOWEVER THIS WILL CHANGE FOR FRI/SAT. 500MB TROUGH CONTINUES TO BE PROGGED BY OPERATIONAL SOLUTIONS AND ANTI-CYCLONIC FLOW WILL DEPART TO THE SOUTHEAST. THIS WILL AID IN A STRENGTHENING SOUTHWEST FLOW THUR NGT/FRI AS A FRONTAL BOUNDARY BEGINS TO APPROACH THE REGION. 850MB THERMAL TROUGH OF -2 TO -5 DEG C SHOULD ARRIVE ACROSS THE REGION MIDDAY FRI...THUS TEMPS FRI MAY STRUGGLE TO WARM WITH POSSIBLY THE WARMEST TEMPS FOR THE DAY OCCURRING IN THE MORNING. 500MB SPEED MAX PIVOTS EAST ACROSS THE UPPER MIDWEST/NORTHERN GREAT LAKES...HOWEVER APPEARS TO BE MAINLY MOISTURE STARVED. AT THIS POINT HAVE CONTINUED TO MENTION CHC POPS...AND TEMPS SHOULD BE COOL ENOUGH TO PRODUCE A POSSIBLE RA/SN MIX HOWEVER MOISTURE RAPIDLY PIVOTS NORTHEAST BY FRI AFTN/EVE THAT THIS WOULD BE RESTRICTED TO THE LAKE ENVIRONMENT AND LOWER MICHIGAN. THEN ANTI-CYCLONIC FLOW IS PROGGED TO BUILD BACK INTO THE MIDWEST/GREAT LAKES REGION FOR THE REMAINDER OF THE WEEKEND AND PROVIDE DRY WEATHER. IN ADDITION THE LONGER TERM MODELS CONTINUE TO HINT THAT TEMPS MAY YET AGAIN PUSH BACK ABOVE NORMAL FOR THE SECOND HALF OF THE WEEKEND AND POSSIBLY CONTINUE INTO EARLY THE FOLLOWING WEEK. CONFIDENCE...HIGH. BEACHLER && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEAK LAKE BREEZE MOVING INLAND TO ORD VC 22-23Z TIME-FRAME BACKING WINDS SOMEWHAT FROM SSE TO SE FOR A PERIOD LATE AFTERNOON-EARLY EVENING. TRS //DISCUSSION...UPDATED 18Z... LATEST HI RES RUC AND HRR MODEL OUTPUT CONTINUE TO SUGGEST A WEAK LAKE BREEZE...SUCH AS OCCURRED FRI AND SAT...IS TO DEVELOP AND EVENTUALLY MOVE INLAND TO MDW AND ORD VICINITY 21-22Z TIME-FRAME. RESULT IS THAT 5-10 KT SSE WINDS BACK A BIT TO SE-ESE FOR THE LATE AFTERNOON. MARINE OBS SITES CURRENTLY SHOW A SE WIND DIRECTION AT WAUKEGAN AND BURNHAM HARBORS WITH MESONET OBS INDICATING LIGHT VARIABLE WINDS FROM JUST ASHORE TO A COUPLE MILES INLAND SUGGESTING THE WEAK BOUNDARY IS ALONG THE SHORE AND LITTLE RESISTANCE TO MOVING GRADUALLY INLAND AS CURRENT SMALL TEMPERATURE DIFFERENTIAL BETWEEN LAND AND WATER CONTINUES TO INCREASE. WITH LOSS OF HEATING TOWARDS DUSK AND DISSIPATION OF LAKE BREEZE EARLY IN THE EVENING WINDS TO RETURN TO SSE-S. SPEEDS TO BE LESS THAN 10 KT AS STRONGER SSW FLOW AHEAD OF AN APPROACHING COLD FRONT/SURFACE TROUGH MOVING EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WILL BE DECOUPLED FROM THE SURFACE DURING THE NIGHT. AFTER SUNRISE MONDAY MORNING STRONG...SHALLOW INVERSION WILL BEGIN TO BE ERODED THOUGH WINDS AT TOP OF BOUNDARY LAYER DURING LATER MORNING AND AFTERNOON ARE ONLY 14-17KT. EXPECT SOUTHERLY SURFACE WINDS TO AVERAGE 8-10 KT AFTER SOME SURFACE HEATING AND MIXING WITH POSSIBLE OCCASIONAL GUSTS OF 14-17KT. EXPECT VFR CONDITIONS THROUGHOUT THE VALID TAFOR PERIOD WITH ONLY SCT-BKN MID AND HIGH LEVEL CLOUDS. TRS //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE IN ORD WIND VEERING FM SSE TO SE DURING MID- LATE AFTERNOON DUE TO WEAK LAKE BREEZE MOVING INLAND ACROSS EXTREME NORTHEAST IL. * HIGH CONFIDENCE REMAINDER OF FCST. TRS //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 249 AM CST A BROAD RIDGE ACROSS THE NORTHEASTERN UNITED STATES WILL WEAKEN SOMEWHAT BUT MOVE VERY LITTLE THROUGH THE FIRST HALF OF THE WEEK. THE LOCATION OF THIS FEATURE WILL SUPPORT CONTINUED SOUTHERLY FLOW ACROSS THE LAKE. THE LACK OF A STRONG PRESSURE GRADIENT WILL GENERALLY KEEP WINDS AND WAVES BELOW LEVELS THAT WOULD POSE HAZARDS. THE EXCEPTION WOULD BE ALONG THE FAR NORTHERN SHORE AT THE END OF THE LONG FETCH WHERE SMALL CRAFT HEADLINES ARE IN EFFECT. EVEN THE APPROACH OF A TROUGH FROM THE WEST TOWARD MIDWEEK WILL NOT BE ENOUGH TO BOOST WINDS...SINCE BY THAT TIME THE RIDGE TO THE EAST WILL HAVE WEAKENED SOMEWHAT AND MOVED A BIT FARTHER AWAY TOWARD THE ATLANTIC COAST. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
205 PM CST SUN NOV 18 2012 .DISCUSSION... 321 AM CST SYNOPSIS...SOME THINGS BECOME CLEARER WHILE OTHER PARTS OF THE FORECAST BECOME MORE MUDDLED. OVERALL A GRADUAL WARMING PATTERN IS STILL EXPECTED THROUGH MONDAY...WITH TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND THANKSGIVING. NO SIGNIFICANT PRECIP IS EXPECTED. TODAY THROUGH MONDAY... HIGH PRESSURE CURRENTLY CENTERED OVER SOUTHEASTERN QUEBEC/UPPER NEW ENGLAND STRETCHES THROUGH THE MISSISSIPPI RIVER VALLEY. THE HIGH WILL REMAINED CENTERED THERE THROUGH EARLY NEXT WEEK WITH RELATIVELY QUIET WEATHER EXPECTED LOCALLY. TEMPS WILL BE AROUND 60 TODAY WITH CLEAR SKIES AND SOUTHERLY FLOW. CLOUDS INCREASE TOMORROW AS A THROUGH OF LOW PRESSURE/WEAK COLD FRONT APPROACH FROM THE WEST. AS SUCH WENT WITH TEMPS A DEGREE OR TWO COOLER ON MONDAY...BUT STILL WELL ABOVE AVERAGE. MONDAY NIGHT AND TUESDAY... LOW PRESSURE CURRENTLY OVER WESTERN BRITISH COLUMBIA WILL PUSH EASTWARD THROUGH CANADA...AND MODELS CONTINUE TO PUSH THE LOW FURTHER NORTH. THE LOWS COLD FRONT/LOW PRESSURE TROUGH WILL PASS THROUGH THE AREA. FORCING REMAINS WEAK ALONG THE COLD FRONT THEREFORE EXPECTING A FEW HUNDREDTHS AT BEST MONDAY EVENING THROUGH MONDAY NIGHT. GUIDANCE INDICATES THE TROUGH/COLD FRONT WEAKENS AS IT APPROACHES THE CWA SO THE BEST CHANCE OF PRECIP LOOKS TO BE OVER THE WESTERN AND NORTHERN PORTIONS OF THE CWA MONDAY NIGHT. AND BY BEST CHANCE I MEAN BEST VERY VERY SLIGHT CHANCE. PRECIP MOVES OUT BY TUESDAY MORNING AND HIGH PRESSURE QUICKLY MOVES OVER THE CWA. THINKING TEMPS WILL ONCE AGAIN BE A DEGREE OR TWO HIGHER THAN MONDAY DUE TO WEAK UPPER LEVEL WAA AND CLEARING SKIES. WEDNESDAY AND THANKSGIVING... SOUTHERLY FLOW RETURNS IN FORCE WEDNESDAY AS THE HIGH PRESSURE SLIDES TOWARD THE SOUTHEAST US. 850 HPA TEMPS SOAR TO AROUND 10C WEDNESDAY AND THANKSGIVING...THEREFORE WENT A FEW DEGREES ABOVE ALL-BLEND GUIDANCE ONCE AGAIN. ITS LOOKING LIKE THURSDAY MAY BE THE WARMER OF THE TWO DAYS WITH TEMPS BOTH DAYS AT OR ABOVE 60 DEGREES. MOST PEOPLE WOULD AGREE THAT IS SOMETHING TO BE THANKFUL ABOUT. EXTENDED...THANKSGIVING NIGHT THROUGH SATURDAY... WHAT HAPPENS THANKSGIVING EVENING/NIGHT IS THE BIG FORECAST QUESTION. THE GEM AND ECMWF INDICATE LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS THROUGH WISCONSIN WITH ITS COLD FRONT MOVING THROUGH THE CWA THANKSGIVING NIGHT. THE GFS ON THE OTHER HAND HAS THE LOW MOVING MUCH FARTHER NORTH OVER CENTRAL ONTARIO AND QUEBEC. THE GFS SOLUTION IS ALSO MUCH FASTER THAN THE OTHER TWO SOLUTIONS. SINCE THE GEM AND ECMWF ARE MERGING TOWARD EACH OTHER...LEANING TOWARD THAT SOLUTION. THERE ARE ENOUGH DIFFERENCES IN THE SOLUTIONS THAT DECIDED TO NOT MAKE ANY ADJUSTMENTS TO THE ALL-BLEND TEMPS OR SLIGHT CHANCE POP FORECAST. THAT BEING SAID...IF THE ECMWF SOLUTION IS TO BE BELIEVED...A SIGNIFICANT TEMPERATURE DROP WILL BE EXPECTED BETWEEN THANKSGIVING AND FRIDAY. BY FRIDAY AFTERNOON 850 HPA TEMPS ARE WELL BELOW ZERO. THE GFS FEATURES A MUCH WEAKER COLD AIR PUSH SINCE ITS UPPER LEVEL PATTERN IS VERY ZONAL. NONETHELESS IT DOES FEATURE 850 HPA TEMPS BELOW ZERO MOVING OVERHEAD SATURDAY. JEE && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEAK LAKE BREEZE MOVING INLAND TO ORD VC 22-23Z TIME-FRAME BACKING WINDS SOMEWHAT FROM SSE TO SE FOR A PERIOD LATE AFTERNOON-EARLY EVENING. TRS //DISCUSSION...UPDATED 18Z... LATEST HI RES RUC AND HRR MODEL OUTPUT CONTINUE TO SUGGEST A WEAK LAKE BREEZE...SUCH AS OCCURRED FRI AND SAT...IS TO DEVELOP AND EVENTUALLY MOVE INLAND TO MDW AND ORD VICINITY 21-22Z TIME-FRAME. RESULT IS THAT 5-10 KT SSE WINDS BACK A BIT TO SE-ESE FOR THE LATE AFTERNOON. MARINE OBS SITES CURRENTLY SHOW A SE WIND DIRECTION AT WAUKEGAN AND BURNHAM HARBORS WITH MESONET OBS INDICATING LIGHT VARIABLE WINDS FROM JUST ASHORE TO A COUPLE MILES INLAND SUGGESTING THE WEAK BOUNDARY IS ALONG THE SHORE AND LITTLE RESISTANCE TO MOVING GRADUALLY INLAND AS CURRENT SMALL TEMPERATURE DIFFERENTIAL BETWEEN LAND AND WATER CONTINUES TO INCREASE. WITH LOSS OF HEATING TOWARDS DUSK AND DISSIPATION OF LAKE BREEZE EARLY IN THE EVENING WINDS TO RETURN TO SSE-S. SPEEDS TO BE LESS THAN 10 KT AS STRONGER SSW FLOW AHEAD OF AN APPROACHING COLD FRONT/SURFACE TROUGH MOVING EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WILL BE DECOUPLED FROM THE SURFACE DURING THE NIGHT. AFTER SUNRISE MONDAY MORNING STRONG...SHALLOW INVERSION WILL BEGIN TO BE ERODED THOUGH WINDS AT TOP OF BOUNDARY LAYER DURING LATER MORNING AND AFTERNOON ARE ONLY 14-17KT. EXPECT SOUTHERLY SURFACE WINDS TO AVERAGE 8-10 KT AFTER SOME SURFACE HEATING AND MIXING WITH POSSIBLE OCCASIONAL GUSTS OF 14-17KT. EXPECT VFR CONDITIONS THROUGHOUT THE VALID TAFOR PERIOD WITH ONLY SCT-BKN MID AND HIGH LEVEL CLOUDS. TRS //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE IN ORD WIND VEERING FM SSE TO SE DURING MID- LATE AFTERNOON DUE TO WEAK LAKE BREEZE MOVING INLAND ACROSS EXTREME NORTHEAST IL. * HIGH CONFIDENCE REMAINDER OF FCST. TRS //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 249 AM CST A BROAD RIDGE ACROSS THE NORTHEASTERN UNITED STATES WILL WEAKEN SOMEWHAT BUT MOVE VERY LITTLE THROUGH THE FIRST HALF OF THE WEEK. THE LOCATION OF THIS FEATURE WILL SUPPORT CONTINUED SOUTHERLY FLOW ACROSS THE LAKE. THE LACK OF A STRONG PRESSURE GRADIENT WILL GENERALLY KEEP WINDS AND WAVES BELOW LEVELS THAT WOULD POSE HAZARDS. THE EXCEPTION WOULD BE ALONG THE FAR NORTHERN SHORE AT THE END OF THE LONG FETCH WHERE SMALL CRAFT HEADLINES ARE IN EFFECT. EVEN THE APPROACH OF A TROUGH FROM THE WEST TOWARD MIDWEEK WILL NOT BE ENOUGH TO BOOST WINDS...SINCE BY THAT TIME THE RIDGE TO THE EAST WILL HAVE WEAKENED SOMEWHAT AND MOVED A BIT FARTHER AWAY TOWARD THE ATLANTIC COAST. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 PM CST SUN NOV 18 2012 .DISCUSSION... 321 AM CST SYNOPSIS...SOME THINGS BECOME CLEARER WHILE OTHER PARTS OF THE FORECAST BECOME MORE MUDDLED. OVERALL A GRADUAL WARMING PATTERN IS STILL EXPECTED THROUGH MONDAY...WITH TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND THANKSGIVING. NO SIGNIFICANT PRECIP IS EXPECTED. TODAY THROUGH MONDAY... HIGH PRESSURE CURRENTLY CENTERED OVER SOUTHEASTERN QUEBEC/UPPER NEW ENGLAND STRETCHES THROUGH THE MISSISSIPPI RIVER VALLEY. THE HIGH WILL REMAINED CENTERED THERE THROUGH EARLY NEXT WEEK WITH RELATIVELY QUIET WEATHER EXPECTED LOCALLY. TEMPS WILL BE AROUND 60 TODAY WITH CLEAR SKIES AND SOUTHERLY FLOW. CLOUDS INCREASE TOMORROW AS A THROUGH OF LOW PRESSURE/WEAK COLD FRONT APPROACH FROM THE WEST. AS SUCH WENT WITH TEMPS A DEGREE OR TWO COOLER ON MONDAY...BUT STILL WELL ABOVE AVERAGE. MONDAY NIGHT AND TUESDAY... LOW PRESSURE CURRENTLY OVER WESTERN BRITISH COLUMBIA WILL PUSH EASTWARD THROUGH CANADA...AND MODELS CONTINUE TO PUSH THE LOW FURTHER NORTH. THE LOWS COLD FRONT/LOW PRESSURE TROUGH WILL PASS THROUGH THE AREA. FORCING REMAINS WEAK ALONG THE COLD FRONT THEREFORE EXPECTING A FEW HUNDREDTHS AT BEST MONDAY EVENING THROUGH MONDAY NIGHT. GUIDANCE INDICATES THE TROUGH/COLD FRONT WEAKENS AS IT APPROACHES THE CWA SO THE BEST CHANCE OF PRECIP LOOKS TO BE OVER THE WESTERN AND NORTHERN PORTIONS OF THE CWA MONDAY NIGHT. AND BY BEST CHANCE I MEAN BEST VERY VERY SLIGHT CHANCE. PRECIP MOVES OUT BY TUESDAY MORNING AND HIGH PRESSURE QUICKLY MOVES OVER THE CWA. THINKING TEMPS WILL ONCE AGAIN BE A DEGREE OR TWO HIGHER THAN MONDAY DUE TO WEAK UPPER LEVEL WAA AND CLEARING SKIES. WEDNESDAY AND THANKSGIVING... SOUTHERLY FLOW RETURNS IN FORCE WEDNESDAY AS THE HIGH PRESSURE SLIDES TOWARD THE SOUTHEAST US. 850 HPA TEMPS SOAR TO AROUND 10C WEDNESDAY AND THANKSGIVING...THEREFORE WENT A FEW DEGREES ABOVE ALL-BLEND GUIDANCE ONCE AGAIN. ITS LOOKING LIKE THURSDAY MAY BE THE WARMER OF THE TWO DAYS WITH TEMPS BOTH DAYS AT OR ABOVE 60 DEGREES. MOST PEOPLE WOULD AGREE THAT IS SOMETHING TO BE THANKFUL ABOUT. EXTENDED...THANKSGIVING NIGHT THROUGH SATURDAY... WHAT HAPPENS THANKSGIVING EVENING/NIGHT IS THE BIG FORECAST QUESTION. THE GEM AND ECMWF INDICATE LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS THROUGH WISCONSIN WITH ITS COLD FRONT MOVING THROUGH THE CWA THANKSGIVING NIGHT. THE GFS ON THE OTHER HAND HAS THE LOW MOVING MUCH FARTHER NORTH OVER CENTRAL ONTARIO AND QUEBEC. THE GFS SOLUTION IS ALSO MUCH FASTER THAN THE OTHER TWO SOLUTIONS. SINCE THE GEM AND ECMWF ARE MERGING TOWARD EACH OTHER...LEANING TOWARD THAT SOLUTION. THERE ARE ENOUGH DIFFERENCES IN THE SOLUTIONS THAT DECIDED TO NOT MAKE ANY ADJUSTMENTS TO THE ALL-BLEND TEMPS OR SLIGHT CHANCE POP FORECAST. THAT BEING SAID...IF THE ECMWF SOLUTION IS TO BE BELIEVED...A SIGNIFICANT TEMPERATURE DROP WILL BE EXPECTED BETWEEN THANKSGIVING AND FRIDAY. BY FRIDAY AFTERNOON 850 HPA TEMPS ARE WELL BELOW ZERO. THE GFS FEATURES A MUCH WEAKER COLD AIR PUSH SINCE ITS UPPER LEVEL PATTERN IS VERY ZONAL. NONETHELESS IT DOES FEATURE 850 HPA TEMPS BELOW ZERO MOVING OVERHEAD SATURDAY. JEE && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WEAK LAKE BREEZE MOVING INLAND TO MDW AND ORD VC 21-22Z TIME-FRAME BACKING WINDS SOMEWHAT FROM SSE TO SE. TRS //DISCUSSION...UPDATED 18Z... LATEST HI RES RUC AND HRR MODEL OUTPUT CONTINUE TO SUGGEST A WEAK LAKE BREEZE...SUCH AS OCCURRED FRI AND SAT...IS TO DEVELOP AND EVENTUALLY MOVE INLAND TO MDW AND ORD VICINITY 21-22Z TIME-FRAME. RESULT IS THAT 5-10 KT SSE WINDS BACK A BIT TO SE-ESE FOR THE LATE AFTERNOON. MARINE OBS SITES CURRENTLY SHOW A SE WIND DIRECTION AT WAUKEGAN AND BURNHAM HARBORS WITH MESONET OBS INDICATING LIGHT VARIABLE WINDS FROM JUST ASHORE TO A COUPLE MILES INLAND SUGGESTING THE WEAK BOUNDARY IS ALONG THE SHORE AND LITTLE RESISTANCE TO MOVING GRADUALLY INLAND AS CURRENT SMALL TEMPERATURE DIFFERENTIAL BETWEEN LAND AND WATER CONTINUES TO INCREASE. WITH LOSS OF HEATING TOWARDS DUSK AND DISSIPATION OF LAKE BREEZE EARLY IN THE EVENING WINDS TO RETURN TO SSE-S. SPEEDS TO BE LESS THAN 10 KT AS STRONGER SSW FLOW AHEAD OF AN APPROACHING COLD FRONT/SURFACE TROUGH MOVING EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WILL BE DECOUPLED FROM THE SURFACE DURING THE NIGHT. AFTER SUNRISE MONDAY MORNING STRONG...SHALLOW INVERSION WILL BEGIN TO BE ERODED THOUGH WINDS AT TOP OF BOUNDARY LAYER DURING LATER MORNING AND AFTERNOON ARE ONLY 14-17KT. EXPECT SOUTHERLY SURFACE WINDS TO AVERAGE 8-10 KT AFTER SOME SURFACE HEATING AND MIXING WITH POSSIBLE OCCASIONAL GUSTS OF 14-17KT. EXPECT VFR CONDITIONS THROUGHOUT THE VALID TAFOR PERIOD WITH ONLY SCT-BKN MID AND HIGH LEVEL CLOUDS. TRS //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM CONFIDENCE ON WIND VEERING FM SSE TO SE AND ESE DURING MID AFTERNOON DUE TO WEAK LAKE BREEZE MOVING INLAND. * HIGH CONFIDENCE REMAINDER OF FCST. TRS //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 249 AM CST A BROAD RIDGE ACROSS THE NORTHEASTERN UNITED STATES WILL WEAKEN SOMEWHAT BUT MOVE VERY LITTLE THROUGH THE FIRST HALF OF THE WEEK. THE LOCATION OF THIS FEATURE WILL SUPPORT CONTINUED SOUTHERLY FLOW ACROSS THE LAKE. THE LACK OF A STRONG PRESSURE GRADIENT WILL GENERALLY KEEP WINDS AND WAVES BELOW LEVELS THAT WOULD POSE HAZARDS. THE EXCEPTION WOULD BE ALONG THE FAR NORTHERN SHORE AT THE END OF THE LONG FETCH WHERE SMALL CRAFT HEADLINES ARE IN EFFECT. EVEN THE APPROACH OF A TROUGH FROM THE WEST TOWARD MIDWEEK WILL NOT BE ENOUGH TO BOOST WINDS...SINCE BY THAT TIME THE RIDGE TO THE EAST WILL HAVE WEAKENED SOMEWHAT AND MOVED A BIT FARTHER AWAY TOWARD THE ATLANTIC COAST. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CST SUN NOV 18 2012 .DISCUSSION... ISSUED 1045 AM CST SUN NOV 18 2012 FORECAST LOOKS ON TRACK AGAIN TODAY WITH YET ANOTHER NICE FALL DAY UNFOLDING. MAIN UPDATE IS FOR QUICKER RISE IN THE HOURLY TEMPS THIS MORNING INTO MIDDAY. AMPLE SUNSHINE TODAY AS THIN CIRRUS CLOUDS SPREAD EAST INTO CENTRAL IL. HIGHS IN THE UPPER 50S AND LOWER 60S WITH SSE WINDS 5 TO 10 MPH. LATE MORNING SURFACE MAP SHOWS STRONG 1041 MB HIGH PRESSURE OVER NEW ENGLAND AND RIDGING SW INTO THE MID MS VALLEY. ALOFT AN UPPER LEVEL TROF WAS ALONG THE WEST COAST WTIH UPPER LEVEL RIDGE OVER THE OH/TN VALLEYS WHICH PLACES IL IN A SW FLOW ALOFT. LIGHT FOG/HAZE DISSIPATE BY MID MORNING LEAVING SUNNY SKIES THIS MORNING. TEMPS WERE IN THE UPPER 40S AND LOWER 50S AT 1030 AM WITH SSE WINDS NEAR 8 MPH OR LESS. DEWPOINTS WERE IN THE MIDDLE 30S. MODELS SLOWLY WEAKEN HIGH PRESSURE RIDGE INTO MON AS IT STAYS OVER NEW ENGLAND AND RIDGES SW INTO THE MID MS VALLEY...KEEPING FAIR WEATHER OVER CENTRAL/SE IL. CIRRUS CLOUDS OVER IA AND MORE SCATTERED OVER MO/IL TO GRADUALLY INCREASE OVER CENTRAL IL THROUGH TONIGHT AND LEAD TO BROKEN CIRRUS CLOUDS LATER THIS EVENING. RUC... NAM AND HRRR HAS HIGHS IN THE MID TO UPPER 50S BY MID AFTERNOON ...BUT WENT A FEW DEGREES ABOVE THAT IN THE UPPER 50S AND LOWER 60S SINCE CURRENT TEMPS ARE RUNNING A FEW DEGREES AHEAD OF GUIDANCE. 07 && .AVIATION... ISSUED 532 AM CST SUN NOV 18 2012 QUIET/PREDOMINANTLY VFR AVIATION WEATHER CONDITIONS EXPECTED ACROSS THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID TIME. THIS MORNING WILL BE ANOTHER MORNING WITH PATCHY MVFR FOG FOR A COUPLE HOURS...ALTHOUGH THE AREAL COVERAGE OF THE FOG SHOULD BE LESS THAN THE PAST COUPLE OF DAYS. AN APPROACHING UPPER LEVEL DISTURBANCE WILL SPREAD CIRRUS CIGS ACROSS THE TERMINALS BY LATE TONIGHT...BUT CIGS WILL BE WELL INTO THE VFR CATEGORY. THESE CIGS AND SOUTHERLY WINDS STAYING A BIT STRONGER AT NIGHT SHOULD PRECLUDE FOG REDEVELOPMENT LATER TONIGHT. BAK && .PREV DISCUSSION... ISSUED 250 AM CST SUN NOV 18 2012 CURRENT WEATHER PATTERN NOT MUCH DIFFERENT THAN 24 HRS AGO...WITH AN UPPER LOW OVER THE EXTREME SERN US...AND HIGH PRESSURE RIDGE FROM SERN CANADA TO THE CENTRAL GULF COAST. SFC WINDS IN THE OVERNIGHT LIGHTER...BUT PREDOMINANTLY OUT OF THE S/SE AS THE SUN COMES UP. FORECAST IS ESSENTIALLY ONE OF TEMPERATURES. TWO WAVES ARE PROGGED TO MOVE THROUGH THE QUASI ZONAL FLOW...MON/MON NIGHT...AND AGAIN LATER IN THE WEEK...BUT THE MODELS ARE SKETCHY WITH CONSISTENCY...AND THE ATMOSPHERE WILL BE STRUGGLING TO PRODUCE MOISTURE. AS A RESULT...THE ZONE FORECAST IS RUNNING DRY AT THE MOMENT. TEMPERATURES RUNNING ABOVE NORMAL THROUGH MIDWEEK. SHORT TERM...TODAY AND TOMORROW... RATHER QUIET WEATHER AND S/SERLY WINDS AT THE SFC WITH HIGH PRESSURE RIDGE OVER THE EASTERN HALF OF THE COUNTRY. MILD TEMPS CONTINUE...APPROACHING LOW 60S FOR MUCH OF THE AREA. MOSTLY SUNNY SKIES...AND CLEAR OVERNIGHT WILL COUNTER THE SOUTHERLY FLOW WITH RATHER EFFECTIVE RADIATIONAL COOLING AND TEMPS DROPPING INTO THE UPPER 30S AND NEAR 40. SOUTHERLY WINDS PICK UP A BIT ON MONDAY...AND A BROAD AREA OF WAA PUSHES UNSEASONABLE HEAT INTO THE SW AND CENTRAL PORTIONS OF THE COUNTRY. TEMPS MONDAY A BIT AHEAD OF GUIDANCE...AS THE SLOW WARMING TREND CONTINUES ACROSS THE MIDWEST. LONG TERM...TUESDAY THROUGH SATURDAY... HIGH PRESSURE RIDGE SLOWLY DRIFTS EASTWARD AND THE CLOSED UPPER LOW KICKS OUT OF THE SE. A SHORT WAVE RIPPLES THROUGH THE UPPER ATMOSPHERE...BRINGING A CHANCE FOR SHOWERS MON/MON NIGHT. AND THOUGH THE GFS AND THE NAM ARE BOTH PORTRAYING SOME QPF FOR THE REGION...KEEPING THE POPS RELATIVELY LOW...IN THE SLIGHT CHANCE CAT...AND LACK OF COVERAGE POTENTIAL IF NOTHING ELSE. MOISTURE IS SOMEWHAT LACKING THROUGH THE LAYER AHEAD OF THE SYSTEM. SOUTHERLY WINDS PRIOR TO MONDAY NOT PROVIDING MUCH MOISTURE TRANSPORT INTO THE AREA. WINDS START TO PICK UP A BIT ON MON WITH AN APPROACHING STORM SYSTEM...BUT STILL NOT MUCH IN EXCESS OF 10 KTS. MODELS HAVING A BIT OF AN ISSUE WITH THE WAVE ITSELF...WITH THE ECMWF HOLDING BACK A BIT AND PASSING A MORE VIGOROUS PIECE OF ENERGY LATER ON TUESDAY...ALBEIT A BIT OF AN OUTLIER. WILL WATCH CAREFULLY. ON THE OTHER SIDE OF THE CHANCES FOR SHOWERS MON...THE WARMING TREND CONTINUES THROUGH MID WEEK. 850MB TEMPS AT 6-7C WILL HAVE THE POTENTIAL TO TRANSLATE INTO UPPER 50S/LOWER 60S. GUIDANCE HAS NOT COMPLETELY LATCHED ONTO THE WARMING TREND...THOUGH THE MODEL FIELDS CLEARLY SHOW THE THERMAL RIDGE IN THE WESTERN CONUS DEEPENING AND SLOWLY CREEPING INTO THE MIDWEST. HAVE BUMPED MAX TEMPS A FEW DEGREES AHEAD OF ALLBLEND FOR MON- WED...AND A BIT ON THURSDAY. THURSDAY MAY BE COMPLICATED BY AN APPROACHING STORM SYSTEM AND ASSOCIATED CLOUD COVER...BUT SYSTEM STILL HAS A BIT OF UNCERTAINTY AND WOULD ALSO HAVE THE SAME PROBLEM AS MONDAYS WAVE WITH SCANT MOISTURE. KEEPING THE POPS LOW AND THE TEMPS A COUPLE OF DEGREES ABOVE GUIDANCE...BUT MODERATE FOR NOW. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1003 AM CST SUN NOV 18 2012 .DISCUSSION... 321 AM CST SYNOPSIS...SOME THINGS BECOME CLEARER WHILE OTHER PARTS OF THE FORECAST BECOME MORE MUDDLED. OVERALL A GRADUAL WARMING PATTERN IS STILL EXPECTED THROUGH MONDAY...WITH TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND THANKSGIVING. NO SIGNIFICANT PRECIP IS EXPECTED. TODAY THROUGH MONDAY... HIGH PRESSURE CURRENTLY CENTERED OVER SOUTHEASTERN QUEBEC/UPPER NEW ENGLAND STRETCHES THROUGH THE MISSISSIPPI RIVER VALLEY. THE HIGH WILL REMAINED CENTERED THERE THROUGH EARLY NEXT WEEK WITH RELATIVELY QUIET WEATHER EXPECTED LOCALLY. TEMPS WILL BE AROUND 60 TODAY WITH CLEAR SKIES AND SOUTHERLY FLOW. CLOUDS INCREASE TOMORROW AS A THROUGH OF LOW PRESSURE/WEAK COLD FRONT APPROACH FROM THE WEST. AS SUCH WENT WITH TEMPS A DEGREE OR TWO COOLER ON MONDAY...BUT STILL WELL ABOVE AVERAGE. MONDAY NIGHT AND TUESDAY... LOW PRESSURE CURRENTLY OVER WESTERN BRITISH COLUMBIA WILL PUSH EASTWARD THROUGH CANADA...AND MODELS CONTINUE TO PUSH THE LOW FURTHER NORTH. THE LOWS COLD FRONT/LOW PRESSURE TROUGH WILL PASS THROUGH THE AREA. FORCING REMAINS WEAK ALONG THE COLD FRONT THEREFORE EXPECTING A FEW HUNDREDTHS AT BEST MONDAY EVENING THROUGH MONDAY NIGHT. GUIDANCE INDICATES THE TROUGH/COLD FRONT WEAKENS AS IT APPROACHES THE CWA SO THE BEST CHANCE OF PRECIP LOOKS TO BE OVER THE WESTERN AND NORTHERN PORTIONS OF THE CWA MONDAY NIGHT. AND BY BEST CHANCE I MEAN BEST VERY VERY SLIGHT CHANCE. PRECIP MOVES OUT BY TUESDAY MORNING AND HIGH PRESSURE QUICKLY MOVES OVER THE CWA. THINKING TEMPS WILL ONCE AGAIN BE A DEGREE OR TWO HIGHER THAN MONDAY DUE TO WEAK UPPER LEVEL WAA AND CLEARING SKIES. WEDNESDAY AND THANKSGIVING... SOUTHERLY FLOW RETURNS IN FORCE WEDNESDAY AS THE HIGH PRESSURE SLIDES TOWARD THE SOUTHEAST US. 850 HPA TEMPS SOAR TO AROUND 10C WEDNESDAY AND THANKSGIVING...THEREFORE WENT A FEW DEGREES ABOVE ALL-BLEND GUIDANCE ONCE AGAIN. ITS LOOKING LIKE THURSDAY MAY BE THE WARMER OF THE TWO DAYS WITH TEMPS BOTH DAYS AT OR ABOVE 60 DEGREES. MOST PEOPLE WOULD AGREE THAT IS SOMETHING TO BE THANKFUL ABOUT. EXTENDED...THANKSGIVING NIGHT THROUGH SATURDAY... WHAT HAPPENS THANKSGIVING EVENING/NIGHT IS THE BIG FORECAST QUESTION. THE GEM AND ECMWF INDICATE LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS THROUGH WISCONSIN WITH ITS COLD FRONT MOVING THROUGH THE CWA THANKSGIVING NIGHT. THE GFS ON THE OTHER HAND HAS THE LOW MOVING MUCH FARTHER NORTH OVER CENTRAL ONTARIO AND QUEBEC. THE GFS SOLUTION IS ALSO MUCH FASTER THAN THE OTHER TWO SOLUTIONS. SINCE THE GEM AND ECMWF ARE MERGING TOWARD EACH OTHER...LEANING TOWARD THAT SOLUTION. THERE ARE ENOUGH DIFFERENCES IN THE SOLUTIONS THAT DECIDED TO NOT MAKE ANY ADJUSTMENTS TO THE ALL-BLEND TEMPS OR SLIGHT CHANCE POP FORECAST. THAT BEING SAID...IF THE ECMWF SOLUTION IS TO BE BELIEVED...A SIGNIFICANT TEMPERATURE DROP WILL BE EXPECTED BETWEEN THANKSGIVING AND FRIDAY. BY FRIDAY AFTERNOON 850 HPA TEMPS ARE WELL BELOW ZERO. THE GFS FEATURES A MUCH WEAKER COLD AIR PUSH SINCE ITS UPPER LEVEL PATTERN IS VERY ZONAL. NONETHELESS IT DOES FEATURE 850 HPA TEMPS BELOW ZERO MOVING OVERHEAD SATURDAY. JEE && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LAKE BREEZE MOVING INLAND TO MDW AND ORD VC 21-22Z TIME-FRAME. TRS //DISCUSSION...UPDATED 14Z... LATEST RUC AND HRR MODEL OUTPUT SUGGESTING A WEAK LAKE BREEZE... SUCH AS OCCURRED FRI AND SAT...DEVELOPING AND MOVING INLAND TO MDW AND ORD VC 21-22Z TIME-FRAME. WINDS EXPECTED TO BECOME A BIT MORE SOUTHERLY LATE MORNING AND EARLY AFTERNOON AND THE BACKING TO SE-ESE THERE TERMINALS FOR LATE AFTERNOON INTO EARLY EVE. TRS PREVIOUS...UPDATED 12Z... HIGH PRESSURE PARKED OVER THE EASTERN UNITED STATES WILL MAINTAIN HIGH CLOUDS AND RELATIVELY LIGHT SOUTH TO SOUTHEASTERLY WINDS OVER THE LOCAL TERMINALS. ALTHOUGH LATEST ASOS OBS AT ISSUANCE TIME WERE SHOWING CALM WINDS...OPTED TO KEEP A SSE DIRECTION AND 5 KTS IN THE TAFS TO HELP CRAFT A PLAN TO START OF THE DAY. THIS ALSO MATCHES THE WINDS REPORTED ELSEWHERE AROUND ORD AS RELAYED BY THE CWSU. DID NOT ATTEMPT TO PIN DOWN GUSTS OR MINOR VARIATIONS IN DIRECTION THAT COULD OCCUR THROUGHOUT THE DAY...THOUGH THERE IS A CHANCE THAT WINDS COULD TURN FARTHER TO THE EAST IN RESPONSE TO A LAKE BREEZE INFLUENCE. LENNING //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM CONFIDENCE ON WIND VEERING FM SSE TO SE AND ESE DURING MID AFTERNOON WITH WEAK LAKE BREEZE MOVING INLAND. * HIGH CONFIDENCE REMAINDER OF FCST. TRS //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 249 AM CST A BROAD RIDGE ACROSS THE NORTHEASTERN UNITED STATES WILL WEAKEN SOMEWHAT BUT MOVE VERY LITTLE THROUGH THE FIRST HALF OF THE WEEK. THE LOCATION OF THIS FEATURE WILL SUPPORT CONTINUED SOUTHERLY FLOW ACROSS THE LAKE. THE LACK OF A STRONG PRESSURE GRADIENT WILL GENERALLY KEEP WINDS AND WAVES BELOW LEVELS THAT WOULD POSE HAZARDS. THE EXCEPTION WOULD BE ALONG THE FAR NORTHERN SHORE AT THE END OF THE LONG FETCH WHERE SMALL CRAFT HEADLINES ARE IN EFFECT. EVEN THE APPROACH OF A TROUGH FROM THE WEST TOWARD MIDWEEK WILL NOT BE ENOUGH TO BOOST WINDS...SINCE BY THAT TIME THE RIDGE TO THE EAST WILL HAVE WEAKENED SOMEWHAT AND MOVED A BIT FARTHER AWAY TOWARD THE ATLANTIC COAST. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
824 AM CST SUN NOV 18 2012 .DISCUSSION... 321 AM CST SYNOPSIS...SOME THINGS BECOME CLEARER WHILE OTHER PARTS OF THE FORECAST BECOME MORE MUDDLED. OVERALL A GRADUAL WARMING PATTERN IS STILL EXPECTED THROUGH MONDAY...WITH TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND THANKSGIVING. NO SIGNIFICANT PRECIP IS EXPECTED. TODAY THROUGH MONDAY... HIGH PRESSURE CURRENTLY CENTERED OVER SOUTHEASTERN QUEBEC/UPPER NEW ENGLAND STRETCHES THROUGH THE MISSISSIPPI RIVER VALLEY. THE HIGH WILL REMAINED CENTERED THERE THROUGH EARLY NEXT WEEK WITH RELATIVELY QUIET WEATHER EXPECTED LOCALLY. TEMPS WILL BE AROUND 60 TODAY WITH CLEAR SKIES AND SOUTHERLY FLOW. CLOUDS INCREASE TOMORROW AS A THROUGH OF LOW PRESSURE/WEAK COLD FRONT APPROACH FROM THE WEST. AS SUCH WENT WITH TEMPS A DEGREE OR TWO COOLER ON MONDAY...BUT STILL WELL ABOVE AVERAGE. MONDAY NIGHT AND TUESDAY... LOW PRESSURE CURRENTLY OVER WESTERN BRITISH COLUMBIA WILL PUSH EASTWARD THROUGH CANADA...AND MODELS CONTINUE TO PUSH THE LOW FURTHER NORTH. THE LOWS COLD FRONT/LOW PRESSURE TROUGH WILL PASS THROUGH THE AREA. FORCING REMAINS WEAK ALONG THE COLD FRONT THEREFORE EXPECTING A FEW HUNDREDTHS AT BEST MONDAY EVENING THROUGH MONDAY NIGHT. GUIDANCE INDICATES THE TROUGH/COLD FRONT WEAKENS AS IT APPROACHES THE CWA SO THE BEST CHANCE OF PRECIP LOOKS TO BE OVER THE WESTERN AND NORTHERN PORTIONS OF THE CWA MONDAY NIGHT. AND BY BEST CHANCE I MEAN BEST VERY VERY SLIGHT CHANCE. PRECIP MOVES OUT BY TUESDAY MORNING AND HIGH PRESSURE QUICKLY MOVES OVER THE CWA. THINKING TEMPS WILL ONCE AGAIN BE A DEGREE OR TWO HIGHER THAN MONDAY DUE TO WEAK UPPER LEVEL WAA AND CLEARING SKIES. WEDNESDAY AND THANKSGIVING... SOUTHERLY FLOW RETURNS IN FORCE WEDNESDAY AS THE HIGH PRESSURE SLIDES TOWARD THE SOUTHEAST US. 850 HPA TEMPS SOAR TO AROUND 10C WEDNESDAY AND THANKSGIVING...THEREFORE WENT A FEW DEGREES ABOVE ALL-BLEND GUIDANCE ONCE AGAIN. ITS LOOKING LIKE THURSDAY MAY BE THE WARMER OF THE TWO DAYS WITH TEMPS BOTH DAYS AT OR ABOVE 60 DEGREES. MOST PEOPLE WOULD AGREE THAT IS SOMETHING TO BE THANKFUL ABOUT. EXTENDED...THANKSGIVING NIGHT THROUGH SATURDAY... WHAT HAPPENS THANKSGIVING EVENING/NIGHT IS THE BIG FORECAST QUESTION. THE GEM AND ECMWF INDICATE LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS THROUGH WISCONSIN WITH ITS COLD FRONT MOVING THROUGH THE CWA THANKSGIVING NIGHT. THE GFS ON THE OTHER HAND HAS THE LOW MOVING MUCH FARTHER NORTH OVER CENTRAL ONTARIO AND QUEBEC. THE GFS SOLUTION IS ALSO MUCH FASTER THAN THE OTHER TWO SOLUTIONS. SINCE THE GEM AND ECMWF ARE MERGING TOWARD EACH OTHER...LEANING TOWARD THAT SOLUTION. THERE ARE ENOUGH DIFFERENCES IN THE SOLUTIONS THAT DECIDED TO NOT MAKE ANY ADJUSTMENTS TO THE ALL-BLEND TEMPS OR SLIGHT CHANCE POP FORECAST. THAT BEING SAID...IF THE ECMWF SOLUTION IS TO BE BELIEVED...A SIGNIFICANT TEMPERATURE DROP WILL BE EXPECTED BETWEEN THANKSGIVING AND FRIDAY. BY FRIDAY AFTERNOON 850 HPA TEMPS ARE WELL BELOW ZERO. THE GFS FEATURES A MUCH WEAKER COLD AIR PUSH SINCE ITS UPPER LEVEL PATTERN IS VERY ZONAL. NONETHELESS IT DOES FEATURE 850 HPA TEMPS BELOW ZERO MOVING OVERHEAD SATURDAY. JEE && .CLIMATE... 321 AM CST A SHIFT IN THE UPPER PATTERN WILL ALLOW SOME MODERATION OF TEMPERATURES GOING INTO THE WEEKEND AND PREVAILING FOR SEVERAL DAYS THEREAFTER. WHILE THE MODERATION WILL HELP OBSERVED TEMPERATURES TO EXCEED DAILY NORMALS THE FACT THAT INCREASINGLY SHORTER DAYS AND LOWERING SUN ANGLES RESULT IN THE NORMAL HIGH TEMPERATURE FALLING BY 1 DEGREE F ABOUT EVERY 2 DAYS. SO...IT IS THE COMBINATION OF THE LOWERING NORMAL MAXIMUM TEMPERATURES ALONG WITH THE WARMING THAT WILL RESULT IN DAYTIME TEMPERATURES TO CLIMB TO ABOVE NORMAL...WHICH ARE NOW ONLY IN THE UPPER 40S AT MID NOVEMBER. NORMALS... CHICAGO ROCKFORD MAX MIN MAX MIN NOV 01 56 38 56 36 NOV 17 47 32 47 30 NOV 30 40 27 39 24 THIS UNUSUAL PATTERN WILL ALSO ALLOW HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY...THANSKGIVING...TO COME CLOSE TO THE RECORD HIGH TEMPERATURES. WHILE FORECASTED HIGH TEMPERATURES ARE CURRENTLY A FEW DEGREES COOLER THAN THE RECORDS...HERE ARE THE THE MAX TEMPERATURE RECORDS FOR FOOD FOR THOUGHT: CHICAGO ROCKFORD NOV 21 72 1913 73 1913 NOV 22 69 1913 69 2010 TRS/JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * LAKE BREEZE MOVING INLAND TO MDW AND ORD VC 21-22Z TIME-FRAME. TRS //DISCUSSION...UPDATED 14Z... LATEST RUC AND HRR MODEL OUTPUT SUGGESTING A WEAK LAKE BREEZE... SUCH AS OCCURRED FRI AND SAT...DEVELOPING AND MOVING INLAND TO MDW AND ORD VC 21-22Z TIME-FRAME. WINDS EXPECTED TO BECOME A BIT MORE SOUTHERLY LATE MORNING AND EARLY AFTERNOON AND THE BACKING TO SE-ESE THERE TERMINALS FOR LATE AFTERNOON INTO EARLY EVE. TRS PREVIOUS...UPDATED 12Z... HIGH PRESSURE PARKED OVER THE EASTERN UNITED STATES WILL MAINTAIN HIGH CLOUDS AND RELATIVELY LIGHT SOUTH TO SOUTHEASTERLY WINDS OVER THE LOCAL TERMINALS. ALTHOUGH LATEST ASOS OBS AT ISSUANCE TIME WERE SHOWING CALM WINDS...OPTED TO KEEP A SSE DIRECTION AND 5 KTS IN THE TAFS TO HELP CRAFT A PLAN TO START OF THE DAY. THIS ALSO MATCHES THE WINDS REPORTED ELSEWHERE AROUND ORD AS RELAYED BY THE CWSU. DID NOT ATTEMPT TO PIN DOWN GUSTS OR MINOR VARIATIONS IN DIRECTION THAT COULD OCCUR THROUGHOUT THE DAY...THOUGH THERE IS A CHANCE THAT WINDS COULD TURN FARTHER TO THE EAST IN RESPONSE TO A LAKE BREEZE INFLUENCE. LENNING //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN VSBYS STAYING WELL ABOVE IFR...BUT BRIEF REDUCTIONS DUE TO HAZE ARE POSSIBLE THROUGH SUNRISE. * MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS TODAY AND THIS EVENING. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR WITH SLIGHT CHANCE OF LIGHT RAIN. TUESDAY AND WEDNESDAY...VFR. THANKSGIVING...VFR WITH A CHANCE OF SHOWERS LATE. FRIDAY AND SATURDAY...VFR. LENNING && .MARINE... 249 AM CST A BROAD RIDGE ACROSS THE NORTHEASTERN UNITED STATES WILL WEAKEN SOMEWHAT BUT MOVE VERY LITTLE THROUGH THE FIRST HALF OF THE WEEK. THE LOCATION OF THIS FEATURE WILL SUPPORT CONTINUED SOUTHERLY FLOW ACROSS THE LAKE. THE LACK OF A STRONG PRESSURE GRADIENT WILL GENERALLY KEEP WINDS AND WAVES BELOW LEVELS THAT WOULD POSE HAZARDS. THE EXCEPTION WOULD BE ALONG THE FAR NORTHERN SHORE AT THE END OF THE LONG FETCH WHERE SMALL CRAFT HEADLINES ARE IN EFFECT. EVEN THE APPROACH OF A TROUGH FROM THE WEST TOWARD MIDWEEK WILL NOT BE ENOUGH TO BOOST WINDS...SINCE BY THAT TIME THE RIDGE TO THE EAST WILL HAVE WEAKENED SOMEWHAT AND MOVED A BIT FARTHER AWAY TOWARD THE ATLANTIC COAST. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
307 AM CST SUN NOV 18 2012 .DISCUSSION... ISSUED 250 AM CST SUN NOV 18 2012 CURRENT WEATHER PATTERN NOT MUCH DIFFERENT THAN 24 HRS AGO...WITH AN UPPER LOW OVER THE EXTREME SERN US...AND HIGH PRESSURE RIDGE FROM SERN CANADA TO THE CENTRAL GULF COAST. SFC WINDS IN THE OVERNIGHT LIGHTER...BUT PREDOMINANTLY OUT OF THE S/SE AS THE SUN COMES UP. FORECAST IS ESSENTIALLY ONE OF TEMPERATURES. TWO WAVES ARE PROGGED TO MOVE THROUGH THE QUASI ZONAL FLOW...MON/MON NIGHT...AND AGAIN LATER IN THE WEEK...BUT THE MODELS ARE SKETCHY WITH CONSISTENCY...AND THE ATMOSPHERE WILL BE STRUGGLING TO PRODUCE MOISTURE. AS A RESULT...THE ZONE FORECAST IS RUNNING DRY AT THE MOMENT. TEMPERATURES RUNNING ABOVE NORMAL THROUGH MIDWEEK. SHORT TERM...TODAY AND TOMORROW... RATHER QUIET WEATHER AND S/SERLY WINDS AT THE SFC WITH HIGH PRESSURE RIDGE OVER THE EASTERN HALF OF THE COUNTRY. MILD TEMPS CONTINUE...APPROACHING LOW 60S FOR MUCH OF THE AREA. MOSTLY SUNNY SKIES...AND CLEAR OVERNIGHT WILL COUNTER THE SOUTHERLY FLOW WITH RATHER EFFECTIVE RADIATIONAL COOLING AND TEMPS DROPPING INTO THE UPPER 30S AND NEAR 40. SOUTHERLY WINDS PICK UP A BIT ON MONDAY...AND A BROAD AREA OF WAA PUSHES UNSEASONABLE HEAT INTO THE SW AND CENTRAL PORTIONS OF THE COUNTRY. TEMPS MONDAY A BIT AHEAD OF GUIDANCE...AS THE SLOW WARMING TREND CONTINUES ACROSS THE MIDWEST. LONG TERM...TUESDAY THROUGH SATURDAY... HIGH PRESSURE RIDGE SLOWLY DRIFTS EASTWARD AND THE CLOSED UPPER LOW KICKS OUT OF THE SE. A SHORT WAVE RIPPLES THROUGH THE UPPER ATMOSPHERE...BRINGING A CHANCE FOR SHOWERS MON/MON NIGHT. AND THOUGH THE GFS AND THE NAM ARE BOTH PORTRAYING SOME QPF FOR THE REGION...KEEPING THE POPS RELATIVELY LOW...IN THE SLIGHT CHANCE CAT...AND LACK OF COVERAGE POTENTIAL IF NOTHING ELSE. MOISTURE IS SOMEWHAT LACKING THROUGH THE LAYER AHEAD OF THE SYSTEM. SOUTHERLY WINDS PRIOR TO MONDAY NOT PROVIDING MUCH MOISTURE TRANSPORT INTO THE AREA. WINDS START TO PICK UP A BIT ON MON WITH AN APPROACHING STORM SYSTEM...BUT STILL NOT MUCH IN EXCESS OF 10 KTS. MODELS HAVING A BIT OF AN ISSUE WITH THE WAVE ITSELF...WITH THE ECMWF HOLDING BACK A BIT AND PASSING A MORE VIGOROUS PIECE OF ENERGY LATER ON TUESDAY...ALBEIT A BIT OF AN OUTLIER. WILL WATCH CAREFULLY. ON THE OTHER SIDE OF THE CHANCES FOR SHOWERS MON...THE WARMING TREND CONTINUES THROUGH MID WEEK. 850MB TEMPS AT 6-7C WILL HAVE THE POTENTIAL TO TRANSLATE INTO UPPER 50S/LOWER 60S. GUIDANCE HAS NOT COMPLETELY LATCHED ONTO THE WARMING TREND...THOUGH THE MODEL FIELDS CLEARLY SHOW THE THERMAL RIDGE IN THE WESTERN CONUS DEEPENING AND SLOWLY CREEPING INTO THE MIDWEST. HAVE BUMPED MAX TEMPS A FEW DEGREES AHEAD OF ALLBLEND FOR MON- WED...AND A BIT ON THURSDAY. THURSDAY MAY BE COMPLICATED BY AN APPROACHING STORM SYSTEM AND ASSOCIATED CLOUD COVER...BUT SYSTEM STILL HAS A BIT OF UNCERTAINTY AND WOULD ALSO HAVE THE SAME PROBLEM AS MONDAYS WAVE WITH SCANT MOISTURE. KEEPING THE POPS LOW AND THE TEMPS A COUPLE OF DEGREES ABOVE GUIDANCE...BUT MODERATE FOR NOW. HJS && .AVIATION... ISSUED 1137 PM CST SAT NOV 17 2012...FOR THE 06Z TAFS FORECAST RAP SOUNDINGS ARE STILL INDICATING MVFR VIS OF 4-5SM BR WILL BE POSSIBLE LATER TONIGHT. BASED ON A SIMILAR AIRMASS TO LAST NIGHT...WE KEPT A MENTION OF MVFR FOG AT ALL BUT BMI FOR SEVERAL HOURS FROM 10/11Z TO 15/16Z. CIRRUS CLOUDS HAVE MAINLY CLEARED OUT TO THE EAST...SO RADIATIONAL COOLING CONDITIONS WILL SUPPORT OUR AIR TEMPS DIPPING TO NEAR THE WET BULB LATER TONIGHT. LIGHT SOUTHEAST OR CALM WINDS WILL PREVAIL DUE TO THE WEAK PRESSURE GRADIENT AND THE PROXIMITY OF THE SURFACE RIDGE AXIS ACROSS OUR SOUTHEASTERN COUNTIES. LITTLE CHANGE IS EXPECTED FOR SUNDAY...WITH SOUTHEAST WINDS LESS THAN 10KT AND PERIODIC CIRRUS CLOUDS. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1137 PM CST SAT NOV 17 2012 .DISCUSSION... ISSUED 900 PM CST SAT NOV 17 2012 THE LARGE SURFACE HIGH EXTENDING FROM MAINE TO EASTERN TEXAS WILL BE IN CONTROL OF OUR WEATHER OVERNIGHT. THE RIDGE AXIS EXTENDS ACROSS OUR FAR EASTERN COUNTIES...WHICH WILL HELP KEEP WINDS LIGHT SOUTHEAST OR CALM OVERNIGHT. CIRRUS CLOUDS MAY DRIFT ACROSS THE SKY OCCASIONALLY TONIGHT...BUT ENOUGH CLEARING SHOULD DEVELOP TO PROVIDE FAVORABLE RADIATIONAL COOLING CONDITIONS. THAT WILL ALLOW TEMPS TO DIP INTO THE LOWER 30S BY SUNRISE SUNDAY. SOME LIGHT FOG MAY DEVELOP LATE TONIGHT...BUT VISIBILITY SHOULD REMAIN 4SM OR BETTER...SO NO REAL NEED TO ADD TO THE GRIDS AS IMPACT WILL BE NEGLIGIBLE. AS THE RIDGE AXIS SHIFTS FARTHER EAST OF ILLINOIS SUNDAY MORNING...MID LEVEL TEMPS WILL BEGIN WARMING ON INCREASING SOUTHERLY WINDS. THAT WILL HELP PUSH HIGH TEMPS A FEW DEGREES WARMER THAN SATURDAY. OUR LOW TEMP FORECAST TONIGHT LOOKED ON TRACK WITH EXPECTED CONDITIONS. NO CHANGES APPEARED NECESSARY IN THE REMAINING GRIDS FOR TONIGHT OR EARLY TOMORROW. NO FORMAL UPDATE WILL BE NEEDED THIS EVENING. SHIMON && .AVIATION... ISSUED 1137 PM CST SAT NOV 17 2012...FOR THE 06Z TAFS FORECAST RAP SOUNDINGS ARE STILL INDICATING MVFR VIS OF 4-5SM BR WILL BE POSSIBLE LATER TONIGHT. BASED ON A SIMILAR AIRMASS TO LAST NIGHT...WE KEPT A MENTION OF MVFR FOG AT ALL BUT BMI FOR SEVERAL HOURS FROM 10/11Z TO 15/16Z. CIRRUS CLOUDS HAVE MAINLY CLEARED OUT TO THE EAST...SO RADIATIONAL COOLING CONDITIONS WILL SUPPORT OUR AIR TEMPS DIPPING TO NEAR THE WET BULB LATER TONIGHT. LIGHT SOUTHEAST OR CALM WINDS WILL PREVAIL DUE TO THE WEAK PRESSURE GRADIENT AND THE PROXIMITY OF THE SURFACE RIDGE AXIS ACROSS OUR SOUTHEASTERN COUNTIES. LITTLE CHANGE IS EXPECTED FOR SUNDAY...WITH SOUTHEAST WINDS LESS THAN 10KT AND PERIODIC CIRRUS CLOUDS. SHIMON && .PREV DISCUSSION... ISSUED 246 PM CST SAT NOV 17 2012 ANOTHER DAY OF NOT MUCH TO TALK ABOUT WITH ONLY CONCERN BEING PCPN CHANCES MON AND MON NIGHT...AND HOW WARM WILL IT GET THROUGH THE PERIOD. MODELS IN THE SHORT TERM REMAIN SIMILAR AND CONSISTENT FROM PREVIOUS RUNS...SO ONLY MAKING MINOR CHANGES TO GOING FORECAST THROUGH TUESDAY. MODELS IN THE LONG TERM CONTINUE TO SHOW DIFFERENCES IN TIMING WITH THE ONE SHORT WAVE/SYSTEM THAT MOVES ACROSS THE AREA ON THANKSGIVING DAY/NIGHT. SO CONFIDENCE HAS NOT CHANGED FROM PREVIOUS FORECASTS. SHORT TERM...TONIGHT THROUGH TUESDAY HIGH PRSS RIDGE OVER THE AREA WILL SLIDE SOUTHEAST TONIGHT AND TOMORROW. THIS SHOULD ALLOW WAA TO OCCUR BACK INTO THE AREA AND AN INCREASE OF LOW LEVEL MOISTURE. HOWEVER...SFC RIDGE WILL EXTEND INTO THE GULF AND CUTOFF ANY RETURN OF MOISTURE TO THE AREA EARLY NEXT WEEK. SO THE FRONTAL SYSTEM THAT IS MOVING TOWARD AND INTO THE AREA MON NIGHT THROUGH TUE WILL HAVE VERY LIMITED MOISTURE TO WORK WITH. SO WILL KEEP CURRENT FORECAST PRETTY CLOSE TO AS IS AND STILL HAVE SLIGHT CHC FOR SHOWERS IN THE WEST FOR MONDAY AND ACROSS THE WHOLE AREA FOR MONDAY NIGHT. ANY PCPN SHOULD BE WELL IN THE WARM SECTOR SO AS THE FRONT MOVES INTO THE AREA FOR TUESDAY...ANY PCPN WILL BE JUST EAST OF THE STATE. DAYTIME TEMPS WILL BE ABOVE NORMAL ACROSS THE AREA. FOLLOWED WARMER GUIDANCE...MET...FOR SUNDAY AND THEN BLEND FOR MONDAY AND TUESDAY. SHOULD BE PLENTY OF SUNSHINE TOMORROW...THEN WILL HAVE TO RELY ON WAA ON MONDAY AND TUESDAY...WHICH WILL HAVE LITTLE MORE CLOUD COVER. LONG TERM...TUESDAY NIGHT THROUGH SATURDAY STILL LOOKING AT A SOMEWHAT ZONAL PATTERN FOR REMAINDER OF THE WEEK. BOTH MODELS SHOW A TROUGH/FRONTAL SYSTEM MOVING THROUGH THE AREA THURSDAY-THURSDAY NIGHT...BUT TIMING DIFFERENCES HAVE GFS QUICKER THAN ECMWF. ECMWF IS ALSO DEEPER WITH MID LEVEL TROUGH THURSDAY NIGHT. SO WITH TIMING DIFFERENCES...WILL KEEP SLIGHT CHC POPS IN GRIDS FOR THURSDAY NIGHT IN SOUTHEAST CWA...WHICH IS CLOSE TO GOING FORECAST. REMAINDER OF THE TIME PERIOD WILL BE DRY AS MOISTURE WILL REMAIN CUTOFF BY THE SFC RIDGE SITTING OVER THE SOUTHEASTERN US AND INTO THE WESTERN GULF. TEMPS WILL REMAIN WARM/ABOVE NORMAL WED AND THURSDAY...BUT THEN COOL SOME FOR FRIDAY AND SAT...THOUGH STILL SLIGHTLY ABOVE NORMAL. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
606 PM CST MON NOV 19 2012 .AVIATION... A WEAK COLD FRONT WILL MOVE THROUGH EASTERN IOWA AND NORTHWEST ILLINOIS AFTER MIDNIGHT. THERE IS A GREAT DEAL OF UNCERTAINTY CONCERNING THE CLOUD TRENDS OVER THE AREA TONIGHT. THE TAFS WERE WRITTEN ON THE ASSUMPTION THAT MVFR CIGS WILL DEVELOP OR REMAIN NEAR THE MISSISSIPPI RIVER OVERNIGHT AND CLEARING WILL TAKE PLACE TO THE WEST. AS THE COLD FRONT MOVES THROUGH AFTER MIDNIGHT LIGHT WINDS AND HIGH MOISTURE LEVELS WILL AID IN THE DEVELOPMENT OF FOG. VISIBILITIES UNDER THE CLOUD DECK ALONG AND EAST OF THE MISSISSIPPI RIVER ARE EXPECTED TO STAY IN THE 3SM TO 5SM RANGE LATE TONIGHT AND TUESDAY MORNING. TO THE WEST...INCLUDING KCID...WHERE CLEARING IS EXPECTED THERE IS A GREATER POTENTIAL FOR FOG WITH IFR VISIBILITIES AND POSSIBLY CIGS. LIFR CONDITIONS IN DENSE FOG BEWTEEN 09Z AND 15Z CANNOT BE RULED OUT AT THIS TIME. CONDITIONS AT ALL SITES WILL GRADUALLY IMPROVE AS NORTHWEST WINDS AROUND 10KTS DRAW IN DRIER AIR LATE TUESDAY MORNING AND TUESDAY AFTERNOON. DLF && .PREV DISCUSSION... /ISSUED 315 PM CST MON NOV 19 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS SEVERAL WEAK TROFS FROM THE WESTERN GREAT LAKES INTO THE ROCKIES. AT 850MB A MOISTURE PLUME EXTENDED FROM THE BAY OF CAMPECHE UP INTO CENTRAL IOWA. RADAR TRENDS THROUGH EARLY AFTERNOON SHOW A CONTINUED DECREASE OF THE PRECIPITATION AS THE OVERALL FORCING WEAKENS. AT THE SAME TIME...LOW CLOUDS HAD DEVELOPED ON THE EASTERN EDGE OF THE CLEARING AND WERE NOW OVER THE MID MISSISSIPPI VALLEY. 18Z SFC ANALYSIS HAS A VERY WEAK LOW ALONG THE OK/TX BORDER EAST OF KAMA WITH A TROF EXTENDING NORTH FROM THE LOW INTO NORTHERN MINNESOTA. A WEAK COLD FRONT RAN FROM NORTHWEST MINNESOTA INTO SOUTH DAKOTA. DEW POINTS WERE IN THE 40S AND 50S IN A BROAD MOISTURE PLUME FROM TEXAS INTO IOWA WITH 30S ACROSS THE REMAINDER OF THE MIDWEST AND PLAINS. SHORT TERM...TONIGHT AND TUESDAY... THE ONLY EXPLANATION FOR THE RAPID DEVELOPMENT OF THE LOW CLOUDS ACROSS THE CWFA SINCE LATE MORNING IS CONVERGENT FLOW AHEAD OF THE TROF. THIS CONVERGENCE CONTINUES THIS AFTERNOON SO THE CLOUDS ARE EXPECTED TO REMAIN ACROSS THE AREA. RADAR TRENDS SUGGEST THE POTENTIAL FOR SOME SPRINKLES/VERY LIGHT SHRA TO CONTINUE INTO THE LATE AFTERNOON HOURS AS WELL IN THE EASTERN CWFA. GOING ON THE ASSUMPTION THAT THE RAP TRENDS ARE CORRECT...THE OVERALL CONVERGENCE IS PROGGED TO WEAKEN THIS EVENING WHICH SHOULD ALLOW THE CLOUDS TO PARTIALLY BREAK UP IN THE WESTERN CWFA. IN THE EASTERN CWFA LINGERING SPRINKLES ARE POSSIBLE EARLY THIS EVENING. THE RAP TRENDS AFTER MIDNIGHT ARE DISTURBING. THE CONVERGENT FLOW IS PROGGED TO INCREASE AGAIN AND THE RAP IS INDICATING THAT A WEAK LOW WILL MOVE ALONG THE TROF INTO THE CWFA PRIOR TO SUNRISE. WITH PLENTIFUL LOW LEVEL MOISTURE IN PLACE THE CLOUDS ARE EXPECTED TO RE-DEVELOP OR FOG/STRATUS WILL DEVELOP IN THE CLEAR AREAS. THUS WILL ADD AREAS OF FOG IN THE WESTERN CWFA AND PATCHY FOG EAST WHERE THE CLOUDS ARE EXPECTED TO LINGER LONGER. I CANNOT RULE OUT THE POSSIBILITY OF A HEADLINE FOR THE FOG LATE TONIGHT INTO TUESDAY MORNING. HOW THE CLOUDS AND POTENTIAL FOG DEVELOP/EVOLVE LATE TONIGHT WILL BE THE KEY. IF ONE HAD TO ASSIGN A PROBABILITY IT IS CURRENTLY 1 IN 5 OR 1 IN 4 REGARDING A HEADLINE. ASSUMING THAT LOW CLOUDS/FOG DEVELOP LATE TONIGHT THEY WILL CONTINUE INTO TUESDAY MORNING. THE FOG SHOULD LIFT BY LATE MORNING WITH THE CLOUDS EXPECTED TO CLEAR OUT DURING THE AFTERNOON. THE RATE OF CLEARING ON TUESDAY IS A CONCERN GIVEN THE WEAK SUN. IT IS ENTIRELY POSSIBLE THAT THE CLOUDS MAY NOT CLEAR OUT UNTIL CLOSE TO SUNSET TUESDAY. IF THAT OCCURS...THE CURRENT MAX TEMPERATURES FOR TUESDAY ARE TOO WARM. ..08.. LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY... TUESDAY NIGHT AND WEDNESDAY...BOTH SFC AND UPPER RIDGING STILL ON TRACK TO GET PRESSED ACRS THE REGION THIS PERIOD AS WELL AS UNSEASONABLY MILD TEMPS. LIGHT WINDS AND CLEAR OUT OF CLOUDS WILL MAKE FOR A COOLER NIGHT TUE NIGHT WITH LOWS WELL DOWN IN THE 30S. DEPENDING ON TUE AFTERNOON CLOUD CLEAR OUT...THE LATER THE CLEARING TREND AND THUS REDUCING THE SFC MIX OUT DRYING...TUE NIGHT MAY BE AN IDEAL RADIATIONAL FOG SET UP ESPECIALLY ALONG AND EAST OF THE MS RVR. WILL HOLD OFF MENTION FOR NOW BUT FOLLOWING SHIFTS WILL HAVE TO ASSESS THIS POTENTIAL. AS FOR WED...TEMPORARY OMEGA BLOCK OVER STRENGTHENING WARMING LLVL RETURN FLOW STILL APPEAR ON TAP. EXTENT OF AVERAGED LLVL THERMAL DRAW BY THE MAJORITY OF THE NEW 12Z RUN MODELS AND MIXING UP INTO BASE ON BUILDING WARM WEDGE ALOFT SUPPORTS WIDESPREAD HIGHS IN THE UPPER 50S IN THE FAR NORTHEAST...TO THE MID 60S IN THE SOUTHWEST. UNSEASONABLY MILD WED NIGHT AND IF SOUTHERLY SFC WINDS CAN MAINTAIN AT 5-10 KTS...MANY AREAL TEMPS WILL BE HELD UP FROM DIPPING BELOW THE MID-UPPER 40S. BUT MAY PLAY IT COOLER IN CASE OF ANY SFC WIND DECREASE EVEN IF TEMPORARY. THURSDAY AND FRIDAY... INCOMING PACIFIC NW WAVE ENERGY/DEVELOPING CYCLONE ACRS THE NORTHERN PLAINS AND ASSOCIATED SFC FRONT PROJECTED BY LATER RUNS TO SWEEP THROUGH THE DVN CWA THU EVENING. ACTUAL FROPA OCCURRING ACRS THE MS RVR FROM THE WEST PROGGED BY ENSEMBLE MEAN NOW LOOKS TO OCCUR AROUND OR JUST AFTER 00Z FRI...THUS THE BULK OF THU THE DVN CWA TO BE IN BREEZY PRE-FRONTAL WARM SECTOR. STOUT INVERSION ALOFT AND INCREASE IN LOW-TO-MID LEVEL MOISTURE/CLOUDS COULD BE THE LIMITING FACTOR AND PREVENT A RECORD MILD THANKSGIVING. IF IT WERE NOT FOR THOSE FACTORS...SOME AREAS WOULD HIT 70 OR HIGHER. BUT WILL WITH A MORE CONSERVATIVE LOW TO MID 60S. STRENGTH OF LLVL FRONT ITSELF AND MID-UPPER LOW ROLLING ACRS THE UPPER MS RVR VALLEY SHOULD BE ENOUGH TO DEVELOP SOME SHOWERS JUST AHEAD OF THE FRONT THU AFTERNOON AND EVENING EVEN TAKING INTO ACCOUNT SOMEWHAT LIMITED MOISTURE RETURN INTO THE FROPA PROCESS. BUT IF LATER RUNS TREND WETTER...SOME MODERATE SHOWERS AN POSSIBLY EVEN A THUNDERSTORM MAY BE POSSIBLE THU AFTERNOON/EVENING. IT ALL DEPENDS ON ANY BUILD UP OF INSTABILITY IF IT CAN AS THU PROGRESSES. DEPENDING ON THE FRONTAL TIMING...LATE NIGHT SWITCH OVER TO LLVL COLD CONVEYOR COULD PLUNGE MUCH OF THE NORTHWEST HALF OF THE LOCAL FCST AREA INTO THE LOW TO MID 30S. FRIDAY STILL ON TRACK TO BE A MUCH COLDER BLUSTERY DAY IN SUBSIDING DRY SLOT OFF GRT LKS CYCLONE...WITH HIGHS HAVING TROUBLE GETTING OUT OF THE UPPER 30S TO LOWER 40S AS NORTHWEST WINDS GUST OVER 30 MPH. WRAP AROUND SNOW FLURRIES/SHOWERS MAY NOT BE ALL THAT FAR AWAY FROM THE LOCAL AREA ACRS SOUTHERN WI. IF SFC WINDS DECOUPLE UNDER CLEAR SKIES FRI NIGHT...LOWS COULD DIP INTO THE LOWER 20S TO EVEN UPPER TEENS IN SOME LOCATIONS BY EARLY SAT MORNING. SATURDAY THROUGH NEXT MONDAY...LATEST RUN OF THE MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST A QUICK RETURN TO PROGRESSIVE WESTERLIES/ FLATTENED FLOW PATTERN ACRS MUCH OF THE CONUS...THUS DRY AND THERMALLY MODERATING WX INTO SUNDAY AND SUNDAY NIGHT. HIGHS BY SUNDAY BACK INTO THE MID 40S TO NEAR 50 WITH SOME RETURN FLOW MIXING AND INSOLATION. AS FOR EARLY TO MID NEXT WEEK...NORTHERN HEMISPHERIC TELECONNECTIONS SUGGEST ENOUGH WAVE ENERGY/UPPER JET INFLUX DIGGING INTO THE WEST FOR AN EVENTUAL L/W TROF COMPLEX ACRS THE SOUTHWESTERN ROCKIES AND GRT BSN. MANY COMPLEX PHASING ISSUES TO BE RESOLVED THAT FAR OUT...BUT THE GENERAL SIGNAL OF A LOADED SOUTHWEST FLOW PATTERN ACRS THE WESTERN TO MID CONUS WITH COLD AIR TRYING TO DUMP DOWN THE PLAINS AND UPPER MIDWEST WHILE A WARM MOIST CONVEYOR STREAMS UP NORTHWARD TO THE LEE OF THE L/W TROF...COULD MAKE FOR A VERY INTERESTING MID TO LATE WEEK PERIOD. STAY TUNED. ..12.. AVIATION... MVFR CIGS ARE EXPECTED TO PERSIST THROUGH 00Z/20 AND POSSIBLY BEYOND BEFORE LIFTING TO VFR. THE RAP MODEL TRENDS SHOW CONVERGENCE BECOMING STRONGER AFT 06Z/20 WITH PLENTIFUL MOISTURE IN PLACE. THUS THERE IS NOW A REAL CONCERN OF IFR/LIFR CONDITIONS DEVELOPING AFT 06Z/20 WITH THE POTENTIAL FOR VLIFR CONDITIONS. THIS POSSIBILITY IS CURRENTLY NOT IN THE TAFS THAT WERE ISSUED AT 18Z/19. THE 18Z TAFS WILL BE AMENDED TO SHOW MVFR CONDITIONS DEVELOPING AFT 06Z/20 WITH POTENTIAL MARGINAL IFR. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1008 AM MST SUN NOV 18 2012 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 145 AM MST SUN NOV 18 2012 SUMMARY...DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE SHORT TERM PART OF FORECAST. TODAY...DEW POINT DEPRESSIONS CONTINUE TO LOWER EARLY THIS MORNING. LATEST FOG PRODUCT SATELLITE IMAGERY DOES NOT SHOW ANY EVIDENCE OF FOG FORMATION YET...BUT WITH LIGHT SURFACE WINDS...EXPECT SOME PATCHY FOG TO DEVELOP SHORTLY BEFORE SUNRISE MAINLY ALONG HIGHWAY 83. LATEST HRRR MODEL SUPPORTS THIS. OTHERWISE...A WEAK SHORTWAVE TROUGH WILL MOVE ACROSS THE FORECAST AREA DURING THE DAY...BUT RAOBS/MODELS CONTINUE TO SHOW THAT THE AIR MASS WILL BE DRY. ONLY MID AND HIGH LEVEL CLOUDS WILL ADVECT ACROSS THE AREA THIS AFTERNOON. LEE SIDE SURFACE TROUGH WILL MOVE EAST THIS AFTERNOON AND WILL SWITCH WINDS TO THE WEST ALONG THE COLORADO/KANSAS BORDER. WITH LACK OF AIR MASS CHANGE...EXPECT TEMPERATURES TO BE SIMILAR TO THOSE THAT OCCURRED SATURDAY. TONIGHT...500 MB FLOW BECOMES INCREASINGLY ZONAL BEGINNING TONIGHT. MODELS SHOW WEAK COLD AIR ADVECTION AT THE SURFACE STARTING AROUND 12Z. MONDAY...DRY ZONAL MID LEVEL FLOW WILL CONTINUE. SURFACE WINDS WILL BE NORTH BEHIND A PUSH OF SLIGHTLY COOLER AIR. ALTHOUGH 850 MB TEMPERATURES COOL...THE COOLING IS VERY SLIGHT...ONLY ABOUT 1 DEGREE CELSIUS. ONCE AGAIN...PERSISTENCE TEMPERATURE FORECASTS LOOK DECENT. MONDAY NIGHT THROUGH TUESDAY NIGHT...500 MB RIDGE AND ASSOCIATED SUBSIDENCE WILL DEVELOP OVER THE HIGH PLAINS. LEE SIDE TROUGH WILL REFORM BY TUESDAY AFTERNOON BRINGING A RETURN OF SOUTH WINDS AND WEAK WARM AIR ADVECTION. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 145 AM MST SUN NOV 18 2012 VERY LITTLE HAS CHANGED IN THE EXTENDED PERIODS WITH MODELS STILL ADVERTISING PROGRESSIVE ZONAL PATTERN WITH MAIN STORM TRACK ALONG US/CANADA BORDER. THERE ARE A FEW WEAK SHORTWAVE TROUGHS THAT COME CLOSE TO THE CWA...HOWEVER WITH A DEEP DRY LAYER IN PLACE THE MOST WE WOULD EXPECT TO SEE IS AN INCREASE IN MID-HIGH CLOUDS. RH VALUES STILL LOOK TO BE NEAR RFW CRITERIA WEDNESDAY AFTERNOON...HOWEVER SURFACE GRADIENT IS WEAK OVER THE CWA AND WINDS SHOULD BE WELL BELOW CRITERIA. OVERALL...STILL EXPECTING ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS TO CONTINUE. WED HIGHS WILL APPROACH 70F...WITH HIGHS IN THE UPPER 50S/NEAR 60F THROUGH THE REMAINING PERIODS AFTER A WEAK COLD FRONT MOVES THROUGH THE REGION WED NIGHT/THU. OVERNIGHT LOWS SHOULD BE IN THE LOW TO MID 30S EACH NIGHT...WHICH IS IS STILL ABOUT 10F ABOVE NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1006 AM MST SUN NOV 18 2012 VFR CONDITIONS ANTICIPATED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. HIGH CLOUDS WILL GRADUALLY MOVE EAST THROUGH THE REST OF TODAY. LIGHT WESTERLY SURFACE WINDS TONIGHT WILL PREVENT FOG FORMATION...THOUGH WILL NEED TO MONITOR KMCK FOR PATCHY FOG IN THE REPUBLICAN RIVER VALLEY AROUND SUNRISE MONDAY MORNING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...MENTZER SHORT TERM...MENTZER LONG TERM...DR AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
428 AM MST SUN NOV 18 2012 .UPDATE... ISSUED AT 428 AM MST SUN NOV 18 2012 THOUGH MID LEVEL CLOUDS HAVE OCCASIONALLY MOVED ACROSS THE AREA EARLY THIS MORNING...LOW TEMPERATURES AT KITR/KMCK DROPPED INTO THE MID 20S. ADJUSTED THE SHORT TERM GRIDS TO REFLECT THE COOLER TEMPERATURES. TRIBUNE REPORTED SOME LIGHT FOG EARLIER THIS MORNING...AND THE LATEST HRRR CONTINUES TO DEVELOP FOG ACROSS SHERMAN AND THOMAS COUNTIES AFTER SUNRISE. WILL KEEP FOG MENTIONED IN THE FORECASTS FOR A FEW MORE HOURS. && .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 145 AM MST SUN NOV 18 2012 SUMMARY...DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE SHORT TERM PART OF FORECAST. TODAY...DEW POINT DEPRESSIONS CONTINUE TO LOWER EARLY THIS MORNING. LATEST FOG PRODUCT SATELLITE IMAGERY DOES NOT SHOW ANY EVIDENCE OF FOG FORMATION YET...BUT WITH LIGHT SURFACE WINDS...EXPECT SOME PATCHY FOG TO DEVELOP SHORTLY BEFORE SUNRISE MAINLY ALONG HIGHWAY 83. LATEST HRRR MODEL SUPPORTS THIS. OTHERWISE...A WEAK SHORTWAVE TROUGH WILL MOVE ACROSS THE FORECAST AREA DURING THE DAY...BUT RAOBS/MODELS CONTINUE TO SHOW THAT THE AIR MASS WILL BE DRY. ONLY MID AND HIGH LEVEL CLOUDS WILL ADVECT ACROSS THE AREA THIS AFTERNOON. LEE SIDE SURFACE TROUGH WILL MOVE EAST THIS AFTERNOON AND WILL SWITCH WINDS TO THE WEST ALONG THE COLORADO/KANSAS BORDER. WITH LACK OF AIR MASS CHANGE...EXPECT TEMPERATURES TO BE SIMILAR TO THOSE THAT OCCURRED SATURDAY. TONIGHT...500 MB FLOW BECOMES INCREASINGLY ZONAL BEGINNING TONIGHT. MODELS SHOW WEAK COLD AIR ADVECTION AT THE SURFACE STARTING AROUND 12Z. MONDAY...DRY ZONAL MID LEVEL FLOW WILL CONTINUE. SURFACE WINDS WILL BE NORTH BEHIND A PUSH OF SLIGHTLY COOLER AIR. ALTHOUGH 850 MB TEMPERATURES COOL...THE COOLING IS VERY SLIGHT...ONLY ABOUT 1 DEGREE CELSIUS. ONCE AGAIN...PERSISTENCE TEMPERATURE FORECASTS LOOK DECENT. MONDAY NIGHT THROUGH TUESDAY NIGHT...500 MB RIDGE AND ASSOCIATED SUBSIDENCE WILL DEVELOP OVER THE HIGH PLAINS. LEE SIDE TROUGH WILL REFORM BY TUESDAY AFTERNOON BRINGING A RETURN OF SOUTH WINDS AND WEAK WARM AIR ADVECTION. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 145 AM MST SUN NOV 18 2012 VERY LITTLE HAS CHANGED IN THE EXTENDED PERIODS WITH MODELS STILL ADVERTISING PROGRESSIVE ZONAL PATTERN WITH MAIN STORM TRACK ALONG US/CANADA BORDER. THERE ARE A FEW WEAK SHORTWAVE TROUGHS THAT COME CLOSE TO THE CWA...HOWEVER WITH A DEEP DRY LAYER IN PLACE THE MOST WE WOULD EXPECT TO SEE IS AN INCREASE IN MID-HIGH CLOUDS. RH VALUES STILL LOOK TO BE NEAR RFW CRITERIA WEDNESDAY AFTERNOON...HOWEVER SURFACE GRADIENT IS WEAK OVER THE CWA AND WINDS SHOULD BE WELL BELOW CRITERIA. OVERALL...STILL EXPECTING ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS TO CONTINUE. WED HIGHS WILL APPROACH 70F...WITH HIGHS IN THE UPPER 50S/NEAR 60F THROUGH THE REMAINING PERIODS AFTER A WEAK COLD FRONT MOVES THROUGH THE REGION WED NIGHT/THU. OVERNIGHT LOWS SHOULD BE IN THE LOW TO MID 30S EACH NIGHT...WHICH IS IS STILL ABOUT 10F ABOVE NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 428 AM MST SUN NOV 18 2012 THE MAIN ISSUE WITH THIS FORECAST IS WHETHER FOG WILL FORM FROM 12-15Z. THE LATEST HRRR BRINGS LOWER VISIBILITIES TO KGLD...BUT NOT TO KMCK. SATELLITE IMAGERGY CONTINUES TO SHOW NO EVIDENCE OF FOG. GIVEN DEW POINT DEPRESSIONS OF 2-3 DEGREES AND LITTLE WIND...WILL KEEP MENTION OF FOG WITH VISIBILITIES AROUND THREE MILES AT KGLD. WILL KEEP KMCK FREE OF ANY FOG. REGARDLESS...BOTH SITES WILL BE VFR AFTER 16Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...MENTZER SHORT TERM...MENTZER LONG TERM...DR AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
145 AM MST SUN NOV 18 2012 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 145 AM MST SUN NOV 18 2012 SUMMARY...DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE SHORT TERM PART OF FORECAST. TODAY...DEW POINT DEPRESSIONS CONTINUE TO LOWER EARLY THIS MORNING. LATEST FOG PRODUCT SATELLITE IMAGERY DOES NOT SHOW ANY EVIDENCE OF FOG FORMATION YET...BUT WITH LIGHT SURFACE WINDS...EXPECT SOME PATCHY FOG TO DEVELOP SHORTLY BEFORE SUNRISE MAINLY ALONG HIGHWAY 83. LATEST HRRR MODEL SUPPORTS THIS. OTHERWISE...A WEAK SHORTWAVE TROUGH WILL MOVE ACROSS THE FORECAST AREA DURING THE DAY...BUT RAOBS/MODELS CONTINUE TO SHOW THAT THE AIR MASS WILL BE DRY. ONLY MID AND HIGH LEVEL CLOUDS WILL ADVECT ACROSS THE AREA THIS AFTERNOON. LEE SIDE SURFACE TROUGH WILL MOVE EAST THIS AFTERNOON AND WILL SWITCH WINDS TO THE WEST ALONG THE COLORADO/KANSAS BORDER. WITH LACK OF AIR MASS CHANGE...EXPECT TEMPERATURES TO BE SIMILAR TO THOSE THAT OCCURRED SATURDAY. TONIGHT...500 MB FLOW BECOMES INCREASINGLY ZONAL BEGINNING TONIGHT. MODELS SHOW WEAK COLD AIR ADVECTION AT THE SURFACE STARTING AROUND 12Z. MONDAY...DRY ZONAL MID LEVEL FLOW WILL CONTINUE. SURFACE WINDS WILL BE NORTH BEHIND A PUSH OF SLIGHTLY COOLER AIR. ALTHOUGH 850 MB TEMPERATURES COOL...THE COOLING IS VERY SLIGHT...ONLY ABOUT 1 DEGREE CELSIUS. ONCE AGAIN...PERSISTENCE TEMPERATURE FORECASTS LOOK DECENT. MONDAY NIGHT THROUGH TUESDAY NIGHT...500 MB RIDGE AND ASSOCIATED SUBSIDENCE WILL DEVELOP OVER THE HIGH PLAINS. LEE SIDE TROUGH WILL REFORM BY TUESDAY AFTERNOON BRINGING A RETURN OF SOUTH WINDS AND WEAK WARM AIR ADVECTION. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 145 AM MST SUN NOV 18 2012 VERY LITTLE HAS CHANGED IN THE EXTENDED PERIODS WITH MODELS STILL ADVERTISING PROGRESSIVE ZONAL PATTERN WITH MAIN STORM TRACK ALONG US/CANADA BORDER. THERE ARE A FEW WEAK SHORTWAVE TROUGHS THAT COME CLOSE TO THE CWA...HOWEVER WITH A DEEP DRY LAYER IN PLACE THE MOST WE WOULD EXPECT TO SEE IS AN INCREASE IN MID-HIGH CLOUDS. RH VALUES STILL LOOK TO BE NEAR RFW CRITERIA WEDNESDAY AFTERNOON...HOWEVER SURFACE GRADIENT IS WEAK OVER THE CWA AND WINDS SHOULD BE WELL BELOW CRITERIA. OVERALL...STILL EXPECTING ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS TO CONTINUE. WED HIGHS WILL APPROACH 70F...WITH HIGHS IN THE UPPER 50S/NEAR 60F THROUGH THE REMAINING PERIODS AFTER A WEAK COLD FRONT MOVES THROUGH THE REGION WED NIGHT/THU. OVERNIGHT LOWS SHOULD BE IN THE LOW TO MID 30S EACH NIGHT...WHICH IS IS STILL ABOUT 10F ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1000 PM MST SAT NOV 17 2012 RESTRICTED VISIBILITIES ARE POSSIBLE AT KGLD AND EXPECTED AT KMCK AFTER 10Z OR SO THROUGH 15Z AS LOW LEVEL MOISTURE INCREASES AHEAD OF A SFC TROUGH WHICH BY 12Z WILL BE ALONG THE CO/KS BORDER. THIS TROUGH WILL SLOWLY MOVE EAST THROUGH THE DAY SUNDAY WITH W/NW WINDS BEHIND IT AND SOUTHERLY WINDS AHEAD OF IT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...MENTZER LONG TERM...DR AVIATION...99
AREA FORECAST DISCUSSION
NWS PADUCAH KY
901 PM CST MON NOV 19 2012 .UPDATE... ISSUED AT 849 PM CST MON NOV 19 2012 ALTHOUGH NOT REGISTERED THROUGH SURFACE OBSERVATIONS...THE KVWX RADAR HAS BEEN DETECTING ENOUGH 20+ DBZ RETURNS AT 0.5 DEGREE ELEVATION TO WARRANT THE POTENTIAL FOR AT LEAST ISOLATED SHOWERS OR SPRINKLES REACHING THE SURFACE. WITH THIS IN MIND AND WITH THE ASSISTANCE OF THE HRRR 1KM REFLECTIVITY GUIDANCE...ADDED A SMALL POP/WEATHER CHANCE MAINLY OVER THE WEST KENTUCKY PENNYRILE THROUGH 05Z /11 PM CST/. UPPER AIR CHARTS CONTINUE TO SHOW A SERIES OF MINOR WAVES ROTATING INTO THE BROAD TROUGH WITH THE BASE WEST OF THE WFO PAH FORECAST AREA. DESPITE FLUCTUATIONS IN CLOUD COVER FOR THE REMAINDER OF TONIGHT...ADJUSTED THE NET OPAQUE CLOUD COVER TO MOVE THE CLOUDS WITH THE MEAN FLOW THIS EVENING AND OVERNIGHT. GIVEN THAT SCENARIO...HAD TO INCREASE MINIMUM TEMPERATURES 3-4 DEGREES. IN ADDITION...THE SOUTHERLY WIND COMPONENT SHOULD PERSIST FURTHER INTO THE NIGHT AS AN AGEOSTROPHIC RESPONSE TO THE APPROACHING SHORTWAVES. THIS SHOULD HELP BUOY TEMPERATURES AT MOST LOCATIONS OVERNIGHT. UPDATE ISSUED AT 549 PM CST MON NOV 19 2012 THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 149 PM CST MON NOV 19 2012 CLOUDS AND WEAK SHORT WAVE MOVING THROUGH THE CWA AT THIS TIME. WATER VAPOR IMAGERY CLEARLY SHOWS DRIER AIR WORKING INTO SEMO WHICH IS HELPING TO DRY UP ANY PRECIPITATION LEFT FROM THIS MORNING. MAY HAVE HAD A FEW SPRINKLES OVER RIPLEY AND CARTER COUNTIES...BUT THAT WAS ABOUT IT. THE CLOUDS HAVE AFFECTED TEMPERATURES WITH SEMO REMAINING AROUND 60. THIS CLOUD BANK WILL MOVE ACROSS THE AREA TONIGHT WHICH SHOULD KEEP TEMPERATURES UP COMPARED TO LAST NIGHT. KEPT THE DRY FORECAST GOING AS THE LOWEST 5K FT REMAIN DRY. A SHORTWAVE SEEN ON SATELLITE OVER THE NORTHERN PLAIN WILL MOVE THROUGH OUR AREA ON TUESDAY IN THE FORM OF A WEAK COLD FRONT. THE FRONT SHOULD MOVE THROUGH DURING THE LATE MORNING INTO THE AFTERNOON HOURS WHICH SHOULD ALLOW FOR DECENT HEATING AHEAD OF THE FRONT EXCEPT FOR THE EXTREME EASTERN SECTIONS AS THE CLOUDS ARE EXPECTED TO HANG ON THERE INTO THE EVENING HOURS. NO PRECIPITATION IS EXPECTED WITH THIS FRONTAL PASSAGE. DRIER AIR MOVING MOVES IN ON WEDNESDAY AND WITH CLEAR SKIES AND LIGHT WIND SOME FOG POSSIBLE OVER WESTERN KENTUCKY WEDNESDAY NIGHT INTO THURSDAY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 149 PM CST MON NOV 19 2012 WE WILL START OUT ON THURSDAY WITH AN UPPER LEVEL RIDGE OVERHEAD...THAT WILL BE MOVING EASTWARD WITH TIME. THE 12Z GFS CONTINUES TO BE FASTER...THAN PREVIOUS RUNS AND THE ECMWF IN MOVING THE RIDGE EAST AS THE NEXT SHORTWAVE TROUGH APPROACHES FROM THE WEST. BY 00Z FRI...THE 00Z ECMWF STILL HAS THE UPPER RIDGE OVER THE CWA WITH THE IMPENDING SHORTWAVE ACROSS EASTERN KS/OK. THE 12Z GFS HAS THE UPPER RIDGE AXIS OVER THE APPALACHIANS AT THAT SAME TIME WITH THE SHORTWAVE TROUGH KNOCKING ON OUR WESTERN FRINGES. THE GFS HAS SPENT SEVERAL RUNS TRYING TO FIGURE OUT WHETHER THE WESTERN FRINGES OF THE CWA WILL SEE ANY PRECIP PRIOR TO 00Z FRIDAY...BUT CONSENSUS SAYS THAT THINGS WILL PROBABLY STAY DRY. IN FACT...THE 00Z/12Z ECMWF KEEPS US DRY THROUGH 06Z AND THIS MODEL HAS BEEN FLIP FLOPPING ON THAT FOR A WHILE NOW TOO...WHETHER TO START PRECIP ON THURSDAY EVENING OR OVERNIGHT. THE GFS INDICATE RAIN SHOWERS SHOULD BE MOVING IN FROM THE WEST DURING THE EVENING HOURS ON THANKSGIVING...MOVING EAST DURING THE OVERNIGHT HOURS. THE GFS HAS HAD A PROBLEM OVER THE PAST 2 DAYS...FIGURING OUT HOW LONG THE PRECIP WAS GOING TO LINGER ON FRIDAY. RIGHT NOW...THE 12Z GFS INDICATE THAT FRIDAY MORNING MIGHT END UP BEING DRY. THE SLOWER 00Z/12Z ECMWF STILL HOLDS ONTO RAIN CHANCES THOUGH THROUGH THE MORNING HOURS...AT LEAST IN THE SOUTHEASTERN HALF. THINK THE GOING FORECAST RESEMBLES A GOOD BLEND OF SEVERAL DAYS OF MODEL RUNS AND IS A GOOD COMPROMISE TO ALL OF THOSE RUNS OF THE GFS/ECMWF. THE BOTTOM LINE: CHANCES FOR RAIN WILL BEGIN TO INCREASE AFTER 00Z FRIDAY...AND CONTINUE THROUGH THE NIGHT...AND BEGIN TO TAPER OFF THROUGHOUT THE MORNING HOURS ON FRIDAY. RAINFALL AMTS LOOK TO BE RATHER LIGHT AT THIS POINT...AND GFS ENSEMBLES SUPPORT THIS AS WELL. ON FRIDAY...A NORTHERN STREAM SHORTWAVE WILL BE MOVING ACROSS THE NORTHERN PLAINS AND DOWN INTO THE UPPER MIDWESTERN STATES...AND BRING A NICE POCKET OF COLD AIR WITH IT. AS HAS BEEN THE CASE FOR SEVERAL DAYS NOW...THE ECMWF CONTINUES TO BE DEEPER WITH THIS TROUGH AND HENCE BRINGS THE COLDER AIR FURTHER SOUTH. IN FACT...IT IS A PRETTY POTENT POCKET OF COLD AIR...WITH THE ECMWF SHOWING H850 TEMPS AROUND -11C DEG ACROSS OUR FAR NORTH. HOWEVER...IT APPEARS AS THOUGH THE 12Z GFS HAS LOCKED INTO SOMETHING NOW SINCE IT TOO BRINGS COLDER AIR FURTHER SOUTH. IT IS NOT QUITE LIKE THE ECMWF BUT AT LEAST IT IS CLOSER. PLUS THE GFS ENSEMBLES ARE COLDER THAN THE OPERATIONAL GFS. WE WILL DEFINITELY SEE A DROP IN TEMPS ON FRIDAY AS COLD AIR ADVECTION WILL BE WELL UNDERWAY WITH BRISK NORTHERLY FLOW AT THE SFC. IN FACT...MODELS HAVE BEEN TRENDING COLDER WITH EACH MODEL RUN...SO WILL LOWER HIGHS. HIGHS ON SATURDAY WILL BE QUITE COOL FROM WHAT WE HAVE BEEN USED TO THIS WEEK AND COULD END UP BEING 10 DEG COLDER THAN ON FRIDAY...AS HIGH PRESSURE BUILDS IN AT THE SFC. THE COLDEST TEMPS WILL BE IN OUR EASTERN SECTIONS...WHERE SOME OF THE GUIDANCE IS GIVING HIGHS ONLY IN THE LOW 40S. THERE IS NOW QUITE A BIT OF DIFFERENCE BTWN THE GFS AND ECMWF FOR THE SYSTEM ON SUNDAY AND MONDAY. THE 12Z GFS SHOWS THE HIGH MOVING EAST AS A MOISTURE STARVED COLD FRONT MOVES INTO THE REGION ON SUNDAY. HOWEVER...ON SUNDAY NIGHT...MOISTURE BEGINS TO RETURN NORTH IN EARNEST AND A WARM FRONT STARTS DEVELOPING TO OUR S/SW...WHICH ENDS UP CAUSING SOME OVERRUNNING PRECIP ACROSS OUR SOUTHERN AREAS LATE SUNDAY NIGHT AND INTO MONDAY. THE 00Z ECMWF IS SLOW TO MOVE THE SFC HIGH EAST BUT FINALLY DOES SO SUNDAY AFTERNOON/NIGHT...ALLOWING FOR SOUTHERLY FLOW TO TAKE OVER AND MOISTURE SLOWLY INCREASE OVER THE AREA. HOWEVER...ANY CHANCES FOR RAIN LOOK TO HOLD OFF UNTIL MONDAY/MONDAY NIGHT WITH THE ARRIVAL OF THE FRONT. STILL A LOT OF UNCERTAINTY HERE BUT WHAT DOES SEEM PROBABLE AT THIS POINT IS SEEING AN INCREASE IN TEMPERATURES ON SUNDAY AND MONDAY...BUT WE WILL HAVE TO SEE WHAT HAPPENS WITH FUTURE RUNS ON THE NEXT CHANCE FOR PRECIP. FOR NOW...HAVE ADDED A CHANCE FOR MONDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 549 PM CST MON NOV 19 2012 A WEAK MID/UPPER LEVEL TROUGH WILL PUSH EAST THROUGH THE REGION TONIGHT...WHILE A SLIGHTLY STRONGER SYSTEM PUSHES SOUTH INTO THE REGION LATE TUESDAY. THE SECOND SYSTEM WILL PUSH A WEAK WIND SHIFT THROUGH MUCH OF THE AREA VERY LATE IN THE PERIOD. LIGHT SOUTH TO SOUTHWEST WINDS THIS EVENING WILL GRADUALLY INCREASE AND VEER THROUGH THE DAY TUESDAY UNTIL THE FRONT ARRIVES. DECIDED TO INDICATE A WEAK SHIFT TO THE NORTHWEST IN THE LATE AFTERNOON...EXCEPT AT KOWB WHERE IT WILL NOT LIKELY ARRIVE BEFORE 00Z WEDNESDAY. THERE IS LOW CONFIDENCE IN THE TIMING OF THIS WIND SHIFT...AND IT MAY VERY WELL NOT REACH ANY TAF SITES BEFORE 00Z WEDNESDAY. AS FOR SKIES...MID CLOUDS WILL GRADUALLY LOWER THROUGH THE NIGHT...GENERALLY FROM 10KFT TO AROUND 5KFT BY MORNING. CEILINGS ARE LIKELY THROUGH THE DAY TUESDAY...AND THEY MAY FLIRT WITH 3KFT IN THE AFTERNOON NEAR THE FRONT. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...SMITH SHORT TERM...PS LONG TERM....CW AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
823 AM EST SUN NOV 18 2012 .SYNOPSIS... HIGH PRESSURE WILL MAINTAIN DRY WEATHER AND SEASONAL TEMPERATURES ACROSS THE REGION THROUGH THANKSGIVING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ANOTHER COOL START TO THE MORNING...BUT TEMPERATURES WILL REBOUND NICELY THIS AFTERNOON DUE TO WAA AND KATABATIC WINDS. RIDGES ARE ALREADY MIXED EVIDENT BY LBE IN THE LOWER 40S AS OF 13Z. LOWER ELEVATIONS WILL CATCH UP BY LATE MORNING AS A MCLR SKY IS AGAIN PREDICTED. BUMPED MAXT TEMPS UP A CATEGORY...DUE TO A POSITIVE H8 24HR DELTA OF 2-3 AND MODEST SE WIND TRAJECTORY. HRRR DID AN EXCELLENT JOB ON MAXT YDY...SO FOLLOWED IT TODAY...BUT SHAVED A DEGREE OR TWO OFF THE LOWLANDS IMMEDIATELY ADJACENT TO THE MTNS. THAT SAID...LOOK FOR UPPER 50S TO LOWER 60S TO BE COMMON THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... VERY LITTLE CHANGE IN THE PATTERN UNTIL LATE TUESDAY/WEDNESDAY... WHEN A SHORTWAVE TROUGH WILL SWING THROUGH THE OHIO VALLEY. WILL CONTINUE WITH A DRY FORECAST, AS UPPER LEVEL SUPPORT IS WEAK AND DEEP MOISTURE IS LACKING. THE MAIN EFFECT FROM THE FEATURE WILL BE AN INCREASE IN CLOUDS TUE NIGHT/WED MORNING. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... HIGHLIGHTS... - MEDIUM TO HIGH CONFIDENCE - NO BIG STORMS OVER THE LONG HOLIDAY WEEKEND - NEAR NORMAL TEMPERATURES - FOLLOWED ECMWF EXTENDED FORECAST REMAINS RATHER UNEVENTFUL WHICH IS GOOD GIVEN THE TIME OF YEAR AND THE LARGE NUMBER OF PEOPLE OUT TRAVELING FOR THE UPCOMING HOLIDAY WEEKEND. A TRANSITORY H5 ANTI-CYCLONE ALLOWS A SUNNY AND MILD TURKEY DAY. THE NEXT SYNOPTIC FEATURE WILL BE A WEAK BAROCLINIC ZONE THE SECOND HALF OF FRIDAY. AGAIN...NOT MUCH IN THE WAY OF MOISTURE WITH THIS SYSTEM SO EXPECT MINIMAL QPF AT BEST. NW FLOW RESULTING FROM FAIRLY SIGNIFICANT HEIGHT FALLS OVER NEW ENGLAND ALLOW FOR LAKE EFFECT RW/SW TO DEVELOP SAT. H8 TEMPS AT THIS TIME ARE PROGGED IN THE -8 TO -10C RANGE...BUT DUE TO LESS THAN OPTIMAL INVERSION HEIGHTS...LITTLE ACCUMULATION IS PROJECTED SATURDAY. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... HIGH PRES WL MAINTAIN VFR WEATHER WITH A CLEAR SKY AND LGT WND THROUGH TODAY. .OUTLOOK.../TONIGHT THROUGH THURSDAY/... NO WIDESPREAD RESTRICTION AREAS ARE EXPECTED THIS WEEK ALTHOUGH A CROSSING DISTURBANCE MAY SPAWN SOME LGT SHOWERS AND MID LVL CLDS ON TUESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ NEAR TERM...98
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
332 PM CST Sun Nov 18 2012 .DISCUSSION... Tonight - Monday: The main challenges through this period are the timing/onset of precipitation and the duration into the Monday period. Water vapor imagery was showing the weak upper level disturbance moving out of the Southern Rockies and into the Plains. Radar and visible/IR imagery show what also may be a weak baroclinic zone across south central to eastern Nebraska with a few light returns showing up on radar. The GFS does indicate a slightly tighter theta-e gradient aloft through this area. The radar returns are consistent with the latest HRRR run, albeit a few hours delayed, which develops precipitation in this area this afternoon. Precipitation should increase in coverage across the eastern half of Kansas this evening as the support from the upper wave moves into the region. Think that the timing of precipitation in our western zones will be in the 2-3Z window and persist for 4-6 hours as the whole area moves into our eastern zones. It still looks like coverage will be in the 50% range and precipitation totals will be less than a quarter inch for those that do pick up rain. Precipitation still looks to be coming to end by mid day Monday. There could potentially be a few sprinkles Monday afternoon as another weak wave will be tracking into the area. But models are in good agreement moving any QPF away from the area during the afternoon so the chances of precipitation look too small to mention at this time. High temperatures on Monday will be restrained a bit in our eastern zones as cloud cover will be exiting the area preventing a warm up like our western zones are expected to see. Overall, highs will range from the low to mid 60s in our west to the middle 50s in our east. Tuesday - Tuesday Night: Quiet weather with above normal temperatures are expected this period. High temperatures should climb into the 60s across the area but may be inhibited by weak flow and limited mixing. Overnight lows should be mild for this time of year with lows generally in the low to mid 40s. With light winds overnight, some of our typical low lying/ drainage areas may fall into the 30s. CDB Wednesday - Sunday: Model consensus is a continuation of near to above average temperatures during this period with little in the way of precipitation. Travel day on Wednesday looks outstanding with temperatures nearing the 70 degree mark possible in the far western CWA. Most of the focus is on Thursday/Thanksgiving. An upper level ridge will exit the region on Wednesday as another impulse within the southern stream lifts northeast from the Southern Rockies on Thanksgiving. Despite a lack of low level moisture there is increasing support from the GFS and ECMWF that sufficient mid level Pacific moisture will be available for scattered light showers as a weak cold front drops southeast through MO Thursday night. Have nudged Thursday night pops up to chance category for the far southern counties. A large vortex over the Gulf of Alaska is expected to eject a significant piece of energy eastward at the start of the period. The resulting shortwave trough will dig/deepen southeast through the Upper MS Valley and Great Lakes Thursday night/Friday. Any weather with this feature will track to the north but a secondary cold front will pass through on Friday and reinforce an intrusion of colder air. Have gone along with model consensus on temperatures but the trend is towards more cooling and can envision later forecasts tweaking Friday`s temperatures downward some more. Zonal flow through the mid levels and warm air advection in the boundary layer will return for the dry weekend. MJ && .AVIATION... For the 18Z TAFs, VFR conditions are likely to occur throughout the valid period. The one exception will be for a few hours tonight as an upper level disturbance tracks across the region. As it does, widely scattered to scattered rain showers are possible at the terminals. This system will not have a lot of moisture to work with and the system itself is rather weak. So the result is a higher probability for VFR conditions as the wave is tracking through than sub-VFR conditions. During any showers, ceilings may fall to around 4 to 5 thousand feet and the shower intensity should not be strong enough to restrict visibilities. Outside of the rain chances tonight, winds will be rather strong and gusty from the south this afternoon before diminishing some tonight. Winds will also increase again from the south to southwest by late tomorrow morning or by noon but do not look to be as strong as this afternoon. CDB && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
305 PM CST SUN NOV 18 2012 .SHORT TERM...THROUGH MONDAY AFTERNOON. OVERALL THE BENIGN WEATHER PATTERN OF LATE CONTINUES THROUGH THE NEXT 24 HOURS...WITH THE MAIN FAIRLY MINOR ISSUE CONSISTING OF THE POSSIBILITY OF SPRINKLES ACROSS SOUTHEAST ZONES LATE THIS AFTERNOON INTO THIS EVENING. 20Z OBJECTIVE SURFACE ANALYSIS PLACES A GENERALLY NORTH-SOUTH TROUGH AXIS RUNNING FROM WESTERN SD THROUGH THE NEB PANHANDLE AND DOWN ALONG THE KS/CO BORDER...TRAILING SOUTH FROM A 1005MB LOW AT THE WY/MT/SD INTERSECTION. MEANWHILE...AN EXPANSIVE RIDGE AXIS CONTINUES TO DOMINATE MUCH OF THE EASTERN CONUS. THE CWA LIES ALONG THE INTERFACE BETWEEN THESE TWO FEATURES...WITH A MODEST PRESSURE GRADIENT AND DIURNAL MIXING GENERALLY INTO THE 900-875MB RANGE DRIVING SOUTHERLY SUSTAINED BREEZES TYPICALLY 13-23 MPH WITH GUSTS MAINLY 20-25 MPH. VISIBLE SATELLITE CONFIRMS A RATHER HEALTHY COVERAGE OF MID-HIGH CLOUDS STREAMING OVERHEAD...ESPECIALLY ACROSS THE SOUTHEAST 2/3 OF THE CWA. RADAR EVEN SUGGESTS A FEW SPRINKLES MAY HAVE ALREADY FALLEN THIS AFTERNOON ACROSS PARTS OF NUCKOLLS/THAYER/FILLMORE COUNTIES. THESE CLOUDS SEEM TO BE HAVING A VARYING EFFECT ON TEMPS THIS AFTERNOON...WITH BOTH KS ZONES AND NORTHERN ZONES IN NEB VERY MUCH ON TRACK TO NEAR FORECAST HIGHS IN THE LOW-MID 60S...WHILE CENTRAL AREAS INCLUDING THE TRI-CITIES MAY FALL A BIT SHORT AND STRUGGLE TO REACH 60. THE CLOUDS HAVE LIKELY ALSO REDUCED MIXING SOMEWHAT AND HELD DOWN WIND SPEEDS SLIGHTLY. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICTS BROAD QUASI-ZONAL/SLIGHTLY SOUTHWESTERLY FLOW ACROSS THE CENTRAL/WESTERN CONUS...WITH A PAIR OF FAIRLY VIGOROUS SHORTWAVE TROUGHS TRANSLATING THROUGH THE NORTHERN ROCKIES AND OFF THE PACIFIC NORTHWEST COAST. CLOSER TO HOME...A MORE SUBTLE LOW AMPLITUDE MID LEVEL WAVE IS CURRENTLY LIFTING OUT OF CO/WY...INTO NEB/KS...WITH THE MID-HIGH CLOUDS STREAMING OUT AHEAD OF THIS WAVE LARGELY ASSOCIATED WITH A MODEST 70+KT 300MB JET STREAK. LATE THIS AFTERNOON INTO THIS EVENING...THIS LOW AMPLITUDE MID LEVEL WAVE WILL CONTINUE TRACKING ACROSS THE HEART OF THE CENTRAL PLAINS...WITH THE ONGOING BATCH OF MID-HIGH CLOUDS GRADUALLY CLEARING THE CWA FROM WEST-EAST AND PAVING THE WAY FOR A CLEAR OVERNIGHT. PRIOR TO THIS HOWEVER...THE MOISTURE-STARVED DISTURBANCE WILL CONTINUE TO PROMOTE MODEST THETA-E ADVECTION EVIDENT IN THE 850-700MB LAYER MAINLY OVER THE EASTERN HALVES OF NEB/KS. DESPITE PLENTIFUL DRY AIR ESPECIALLY BELOW 700MB...WILL MAINTAIN A CHANCE OF SPRINKLES THROUGH 10 PM FOR LOCATIONS GENERALLY EAST OF A LINE FROM YORK-NELSON-OSBORNE...WITH ESSENTIALLY ZERO RISK OF PRECIP ACROSS THE REMAINDER OF THE CWA. DESPITE VARIOUS MODELS SUCH AS THE NAM/ECMWF/GFS KEEPING ALL QPF EAST OF THE CWA INTO THIS EVENING...THE WEAK RADAR RETURNS ALREADY OBSERVED WITHIN THE FAR SOUTHEAST CWA THIS AFTERNOON ALONG WITH THE 1KM REFLECTIVITY PROGS FROM THE LATEST HRRR MAKE ME UNWILLING TO COMPLETELY IGNORE SPRINKLE POTENTIAL...ALTHOUGH AGREE WITH PREVIOUS FORECASTER THAT ANYTHING MEASURABLE SHOULD FOCUS WELL EAST/SOUTHEAST OF THE LOCAL AREA. AS MENTIONED...THE OVERNIGHT WILL FEATURE CLEAR SKIES...WHILE AT THE SURFACE...A WEAK TROUGH WILL MOVE EASTWARD ACROSS MAINLY THE WESTERN 1/2 OF THE CWA...TURNING LIGHT BREEZES NORTHWESTERLY IN ITS WAKE. TEMPS OVERNIGHT COULD BE A BIT TRICKY...AS THE NORTHWEST COMPONENT BEHIND THE SURFACE TROUGH COULD ACT TO HOLD THINGS UP...WHILE JUST AHEAD OF THE TROUGH THE COMBINATION OF NEAR-CALM TO LIGHT SOUTHERLY BREEZES AND CLEAR SKIES SHOULD PROMOTE AN EFFICIENT DROP. FEEL THAT A BLEND OF 12Z MET/MAV GUIDANCE IS PROBABLY THE BEST COMPROMISE...AND THUS WILL LOWER MOST OF THE CWA 2-3 DEGREES FROM PREVIOUS FORECAST...BUT STILL KEEPING ALL BUT A FEW NORTHWEST COUNTIES ABOVE FREEZING AND IN THE 33-37 RANGE. ALTHOUGH SUPPOSE SOME HAZE OR LIGHT FOG IS NOT OUT OF THE QUESTION AROUND SUNRISE ESPECIALLY ALONG THE TROUGH AXIS...AM NOT EXPECTING FOG TO BE WORTHY OF A FORMAL MENTION IN THE FORECAST. FOR THE MONDAY DAYTIME PERIOD...TRANQUIL...MOISTURE-STARVED QUASI- ZONAL FLOW WILL CONTINUE ALOFT OVER THE CENTRAL PLAINS...AS THE SHORTWAVE CURRENTLY AFFECTING THE AREA MOVES WELL OFF EAST TOWARD THE GREAT LAKES...WHILE THE SOUTHERN FRINGES OF ANOTHER MID LEVEL WAVE CENTERED OVER THE CANADIAN BORDER BRUSHES INTO WESTERN NEB DURING THE AFTERNOON. WHILE THE MAJORITY OF THE DAY SHOULD REMAIN QUITE SUNNY WITH ONLY A FEW PASSING SPLOTCHES OF HIGH CIRRUS...THE MID-LATE AFTERNOON HOURS COULD FEATURE A BIT GREATER INCOMING CIRRUS COVERAGE MAINLY OVER NORTHWEST ZONES ASSOCIATED WITH THE APPROACHING SHORTWAVE TROUGH. AT THE SURFACE...THE TROUGH AXIS ESSENTIALLY BISECTING THE AREA AT SUNRISE WILL CONTINUE PUSHING SOUTHEAST THROUGH THE DAY. IN ITS WAKE...FAIRLY LIGHT BREEZES OF ONLY AROUND 10 MPH FROM THE NORTH-NORTHWEST WILL PREVAIL. THESE LIGHT WINDS WILL MAKE FOR PLEASANT CONDITIONS THANKS TO THE NEXT IN A LONG STRETCH OF SEASONABLY WARM DAYS. MADE VERY LITTLE CHANGE TO HIGH TEMPS...AND IF ANYTHING NUDGED SOME PLACES UP ANOTHER DEGREE...AIMING FOR LOW 60S NORTHEAST...MID 60S CENTRAL INCLUDING TRI-CITIES...AND UPPER 60S KS ZONES. THE OVERALL BIGGEST CHANGE TO THE MONDAY GRIDS WAS TO DEWPOINTS...WHICH WERE LOWERED 4-7 DEGREES...WITH VALUES ONLY EXPECTED TO AVERAGE IN THE LOW-MID 30S IN MOST AREAS. EVEN SO...RELATIVE HUMIDITY VALUES SHOULD STILL DROP NO LOWER THAN THE UPPER 20S...KEEPING FIRE DANGER QUITE LOW THANKS TO THE LIGHT WINDS. .LONG TERM...STARTING 00Z TUESDAY. GUIDANCE FROM THE OPERATIONAL GFS...GEFS-MEAN AND EC ALL CONTINUE TO SUGGEST MID AND UPPER LEVEL JET ENERGY WILL REMAIN TO THE NORTH OF THE CENTRAL PLAINS THROUGH THE LONG TERM FORECAST PERIOD. A MID LEVEL SHORT WAVE IS EXPECTED TO PUSH ACROSS SOUTHERN CANADA AND THE NORTHERN PLAINS DURING THE DAY THURSDAY...ALONG WITH A WEAK MID LEVEL PERTURBATION WHICH IS EXPECTED PUSH ACROSS THE SOUTHERN PLAINS ALSO ON THURSDAY. ALTHOUGH THESE MID LEVEL DISTURBANCES WILL REMAIN NORTH AND SOUTH OF OUR REGION...AN ASSOCIATED LOW LEVEL BAROCLINIC ZONE IS EXPECTED TO PUSH ACROSS OUR AREA DURING THE DAY THURSDAY. THE OPERATIONAL GFS AND EC BOTH CONTINUE TO SUGGEST LOW LEVEL CONVERGENCE AND RESULTANT FORCING WILL REMAIN WEAK ALONG THIS BAROCLINIC ZONE. ALTHOUGH THERE COULD BE AN INCREASE IN MID TO HIGH LEVEL CLOUDS AS THE MID LEVEL PERTURBATION PUSHES ACROSS THE SOUTHERN PLAINS...AN OVERALL LACK IN KINEMATIC FORCING SHOULD KEEP OUR AREA DRY THROUGHOUT THE LONG TERM FORECAST PERIOD. LITTLE CHANGE IN THE LOW LEVEL AIRMASS TUESDAY THROUGH THURSDAY WILL PRESENT SIMILAR TEMPERATURES EACH DAY...WITH HIGHS GENERALLY IN THE 60S AND LOWS IN THE 30S AND 40S...WHICH IS WELL ABOVE NORMAL FOR THIS TIME OF YEAR. WEAK LOW LEVEL COLD AIR ADVECTION POST FROPA BEGINNING THURSDAY NIGHT WILL THEN PRESENT SOMEWHAT COOLER WEATHER TO FINISH OUT THE WEEK...WITH HIGHS GENERALLY IN THE 50S AND LOWS IN THE 30S...STILL ABOVE NORMAL FOR THIS TIME OF YEAR. && .PREV DISCUSSION... /ISSUED 1116 AM CST SUN NOV 18 2012/ AVIATION...18Z KGRI TAF. VFR CONDITIONS ARE EXPECTED. SURFACE LOW PRESSURE ALONG THE FRONT RANGE OF THE ROCKIES THIS AFTERNOON WILL GRADUALLY SHIFT EASTWARD THROUGHOUT THE TAF PERIOD. AHEAD OF THIS SYSTEM...STRONG SOUTH WINDS WILL CONTINUE WITH WIND SPEEDS NEAR 15 TO 20 MILES PER HOUR. HIGH CIRRUS CAN ALSO BE EXPECTED THROUGHOUT MUCH OF THE DAY...WITH DECREASING CLOUDS AND WIND SPEEDS TOWARDS THE OVERNIGHT HOURS. THE MAIN TROUGH AXIS WILL BEGIN TO SHIFT ACROSS THE REGION AROUND 6Z TO 8Z...WITH WINDS EXPECTED TO SHIFT TO THE WEST NORTHWEST BEHIND THE TROUGH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...BRYANT AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
301 AM MST SUN NOV 18 2012 .DISCUSSION... CURRENTLY...JET FLOW MOVING FROM SOUTHWEST TO NORTHEAST ACROSS THE HEART OF NEW MEXICO...WITH CLINIC IN INERTIAL INSTABILITY ON IR IMAGERY SHOWING COLDEST CLOUD TOPS ON THE NORTH EDGE OF THE FLOW...WITH WARMER TOPS TO THE SOUTH AND EAST. DESPITE IMPRESSIVE SATELLITE DISPLAY...PRECIPITATION HAS BEEN MODEST UPSTREAM...AS DRY AIR MASS AT THE SURFACE IS EVAPORATING MUCH OF WHAT WOULD BE FALLING BEFORE IT HITS THE GROUND. DOME OF HIGH PRESSURE SITTING OVER WESTERN COLORADO WORKING WITH SURFACE TROUGH EXTENDING FROM SOUTHEAST COLORADO ACROSS EASTERN NEW MEXICO TO THE TEXAS BIG BEND COUNTRY...AND THIS MIGHT PERMIT SOME LOW LEVEL STRATUS PENETRATION DRIFTING OUT OF TEXAS AND INTO EASTERN NEW MEXICO HEADING TOWARD SUNRISE. MODELS...IN REASONABLE AGREEMENT THROUGH THE THANKSGIVING HOLIDAY WEEKEND...WITH SOME SIGNIFICANT DIFFERENCES IN PATTERN EVOLUTION AS THE FOLLOWING WORK WEEK GETS STARTED. GOOD CONSENSUS HAS SOUTHWEST FLOW IN CIRCULATION ABOUT NEW GULF OF ALASKA CLOSED LOW CIRCULATING SHORT WAVES AGAINST THE CALIFORNIA COAST THROUGH THE DAY TODAY AND INTO TONIGHT...WITH THESE WAVES PROPAGATING QUICKLY EASTWARD ACROSS NEW MEXICO. WAVE INTENSITY DIMINISHING SHARPLY BY MONDAY MORNING...AS FLOW ALOFT RESETS TO ZONAL...AND BAGGY TROUGH BUILDS FROM SOUTHERN CALIFORNIA SOUTHWARD ACROSS THE TROPICAL EAST PACIFIC ALONG THE BAJA PENINSULA. AS GULF OF ALASKA CLOSED LOW SHIFTS TO THE QUEEN CHARLOTTE ISLANDS OFF THE BRITISH COLUMBIA COAST TUESDAY...RIDGE WILL BUILD OUT OF CENTRAL MEXICO NORTHWARD ACROSS NEW MEXICO AND INTO THE NORTHERN PLAINS...AS EAST PACIFIC TROUGH BEGINS SHEAR TO THE EAST ACROSS ARIZONA...AND THROUGH NEW MEXICO ON WEDNESDAY. WITH TROUGH EXITING TO THE CENTRAL PLAINS ON THANKSGIVING...WINDS ALOFT WILL DECREASE OVER NEW MEXICO...AND RIDGING BUILDS NORTHWARD OUT OF CHIHUAHUA ACROSS NEW MEXICO TO THE SNAKE RIVER VALLEY OF IDAHO AND THE BITTERROOT RANGE OF WESTERN MONTANA. RIDGE WILL START EASTWARD DRIFT ON SATURDAY WITH NEXT TROUGH DEEPENING ON THE WEST COAST AND STARTING SLOW TREK EAST THROUGH SUNDAY. MODELS PART WAYS ON MONDAY...AS DOMESTIC GFS BUILDS AMPLIFYING RIDGE NORTHWARD OVER THE EAST PACIFIC TO PLACE NEW MEXICO IN NORTHWEST FLOW FOR THE FIRST HALF OF THE WORK WEEK. EUROPEAN COLLEAGUES AT ECMWF DIG AMPLIFYING AND MUSCULAR TROUGH OVER THE WESTERN U.S...PLACING NEW MEXICO IN INTENSIFYING SOUTHWEST FLOW IN CIRCULATION ABOUT CLOSED LOW OVER SOUTHWEST CANADA. WILL CONCUR WITH HPC COLLEAGUES WHO POINT OUT GFS TENDENCY TO BE A LITTLE TOO QUICK WITH THIS KIND OF PATTERN...AND WILL LEAN THE FIRST OF THE WORK WEEK TOWARD ECMWF FOR NOW. FOR TODAY...BROAD CLOUDINESS ACROSS NEW MEXICO AS PACIFIC MOISTURE IS SHOVED NORTHWARD AND EASTWARD FROM THE CALIFORNIA COAST IN SOUTHWEST FLOW ALOFT AND AT THE SURFACE. BROAD SHOWER COVERAGE ACROSS WESTERN AND SOUTHERN NEW MEXICO...WITH INCREASED SHOWER COVERAGE AND INTENSITY MAINLY SOUTH OF A LINE FORM ROSWELL TO CLOVIS NEAR THE LEA AND EDDY COUNTY LINES. UP NORTH...A FEW SPOTTY SHOWERS MAY DUST THE SAN JUAN MOUNTAIN PEAKS WITH SNOW NEAR THE COLORADO LINE...WITH LIGHT RAIN MOSTLY OVER SLOPES AND VALLEYS. DEEPENING SURFACE TROUGH FROM EASTERN COLORADO TO THE TEXAS BIG BEND COUNTRY WILL HELP PRODUCE SOME SOUTHWEST BREEZES IN SPOTS OVER THE EASTERN PLAINS THIS AFTERNOON. SOME COOLER AIR FILTERING IN FROM THE NORTH WILL TAKE THE EDGE OFF AFTERNOON TEMPERATURES OVER THE NORTHERN TIER...WITH WARMING TREND CONTINUING ELSEWHERE. EASTERN PLAINS TEMPERATURES WILL RUN 5 TO 10 DEGREES ABOVE NORMAL...WITH NEAR NORMAL TEMPERATURES IN THE EAST. FOR MONDAY...ZONAL FLOW BECOMING ESTABLISHED OVER THE STATE AS NEXT WEST COAST SYSTEM WITH IMPRESSIVE CIRCULATION DRIFTS OUT OF THE GULF OF ALASKA ALONG THE WEST COAST OF CANADA. SOMEWHAT COOLER AIR MASS IN PLACE OVER NEW MEXICO WILL WORK AGAINST CLEARING SKIES AND INCREASES IN SUNSHINE TO KEEP DAYTIME MAXIMUM TEMPERATURES STEADY. SURFACE LOW WILL SHIFT OUT OF EASTERN COLORADO TO THE TEXAS PANHANDLE...ALLOWING LOW LEVEL WINDS TO SHIFT NORTHWEST AND TAP AIR A FEW DEGREES COOLER THROUGH THE DAY. SOME NORTHWEST TO WESTERLY BREEZES POSSIBLE MONDAY AFTERNOON OVER THE EASTERN SLOPES AND ADJACENT PLAINS OF THE CENTRAL MOUNTAIN CHAIN. FOR TUESDAY...RIDGING OVER NEW MEXICO AS BIG BAGGY TROUGH OVER THE BAJA PENINSULA ATTEMPTS TO SHOVE SOME CLOUD AND MOISTURE OUT OF CHIHUAHUA AND THE TEXAS BIG BEND COUNTRY INTO SOUTHEAST NEW MEXICO. MOISTURE WILL BE SLOW IN COMING...AND MOST SHOULD STAY SOUTH OF OUR FORECAST AREA THROUGH TUESDAY NIGHT. STRONG SOUTHERLY COMPONENT TO SURFACE WINDS IN RETURN FLOW. TEMPERATURE TRENDS REMAINING FAIRLY STEADY TUESDAY AFTERNOON...WITH A LITTLE WARMING IN THE WEST OFFSET BY A DEGREE OR TWO OF COOLING IN THE EAST. FOR WEDNESDAY...SHOWERS OVER SOUTHERN NEW MEXICO EXPANDING NORTHWARD TO INTERSTATE 40 WEDNESDAY AFTERNOON...AND THEN SHIFTING FOCUS TO THE SOUTHEAST PLAINS BY WEDNESDAY NIGHT. SOME SOUTHWEST BREEZES OVER THE NORTHEAST PLAINS WEDNESDAY AFTERNOON...HELPED BY DEEPENING SURFACE TROUGH FROM EASTERN COLORADO INTO NORTHEAST NEW MEXICO. STEADY TEMPERATURE TRENDS CONTINUING. OUTLOOK...THANKSGIVING DAY THROUGH SATURDAY...ZONAL FLOW BACK IN PLAY FOR THANKSGIVING DAY UNDER SUNNY SKIES...AND THE LAST OF THE ISOLATED SHOWERS MOVING OUT OF THE SOUTHEAST PLAINS INTO THE HEART OF TEXAS...AND TEMPERATURES STEADY AND ABOVE NORMAL. SAME BASIC STORY FOR FRIDAY. BAGGY TROUGH REDEVELOPING OVER NORTHWEST MEXICO AND THE ADJACENT TROPICAL EAST PACIFIC ON SATURDAY...AS COLD FRONT SAGS SOUTHWARD ACROSS THE EASTERN PLAINS AND TO THE MEXICO BORDER ON SATURDAY. THIS WILL TAKE A FEW DEGREES OFF THE SATURDAY HIGH TEMPERATURE...BUT TEMPERATURES WILL REMAIN 3 TO 8 DEGREES ABOVE LATE NOVEMBER NORMALS. SHY && .FIRE WEATHER... CLOUDS WILL CONTINUE TO STREAM FROM SOUTHWEST TO NORTHEAST ACROSS THE DISTRICT TODAY. THE BEST CHANCES FOR SHOWERS WILL BE OVER THE SOUTHERN THIRD OR SO OF NEW MEXICO WHERE THE DEEPEST MOISTURE AND STRONGEST ATMOSPHERIC LIFT ARE CO-LOCATED. AS THE WEAK UPPER LEVEL PACIFIC TROUGH RESPONSIBLE FOR THE CLOUDS AND SHOWERS OVER SOUTHERN AND CENTRAL NM EJECTS EAST-NORTHEAST THIS AFTERNOON...VERY DRY AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL MOVE IN FROM THE WEST-SOUTHWEST AND BRING A GRADUAL END TO THE SHOWERS. SLIGHTLY COOLER AIR WILL FILTER INTO THE NORTHWEST HALF OF NM THIS AFTERNOON. AS THE COOLER AIR FILTERS IN FROM THE NORTHWEST AND HIGHER DEW POINT LEVELS REMAIN IN PLACE.... VERY GOOD TO EXCELLENT HUMIDITY RECOVERIES ARE EXPECTED OVERNIGHT. THE ONE EXCEPTION WILL BE OVER NORTHEAST NM WHERE BREEZY DOWN SLOPE WEST WINDS WIND WILL KEEP RH RECOVERIES IN THE FAIR TO GOOD RANGE. THE NAM...GFS...AND EUROPEAN WEATHER PREDICTION MODELS ARE IN VERY GOOD AGREEMENT WITH REGARD TO A WEAK UPPER LEVEL TROUGH EJECTING NORTHEASTWARD FROM THE BAJA ACROSS FAR NORTHWEST MEXICO AND SOUTHERN AND CENTRAL NEW MEXICO TUESDAY NIGHT AND WEDNESDAY. AHEAD OF THE SYSTEM...A MOIST SOUTHERLY FLOW WILL TAP UNSEASONABLY DEEP SUBTROPICAL MOISTURE FROM OLD MEXICO. THE GFS IS QUITE A BIT MORE VIGOROUS THAN THE EUROPEAN MODEL WITH THE MOISTURE TRANSPORT AND THE ATMOSPHERIC LIFT ASSOCIATED WITH THE UPPER TROUGH PASSAGE. IN ANY EVENT...THE OVERALL MODEL TREND IS WETTER...WITH THE POTENTIAL FOR SCATTERED WETTING PRECIPITATION OVER THE SOUTH...AND POSSIBLY AS FAR NORTH AS INTERSTATE 40 FOR WEDNESDAY. AFTER GOOD TO EXCELLENT VENTILATION IN MOST LOCATIONS OVER THE WEEKEND...POOR VENTILATION WILL SPREAD ACROSS CENTRAL AND WESTERN PARTS OF THE FORECAST AREA FROM THE WEST DURING THE FIRST HALF OF THE COMING WORK WEEK. VENTILATION IS EXPECTED TO IMPROVE OVER SOUTHERN AND CENTRAL NEW MEXICO...ASSOCIATED WITH THE PASSING THE WEAK UPPER LEVEL TROUGH AND THE ASSOCIATED PRECIPITATION. ECMWF AND CANADIAN MODEL ARE IN VERY GOOD AGREEMENT WITH ONE ANOTHER FOR NEXT WEEKEND INTO EARLY NEXT WEEK...HINTING AT A MAJOR WEATHER PATTERN CHANGE TOWARD COLDER AND WETTER CONDITIONS. STAY TUNED. 33 && .AVIATION... 06Z TAF CYCLE MID/HIGH LEVEL MOISTURE BOWING NORTHWARD OVER SOUTHERN AND CENTRAL NEW MEXICO...WHILE TOP DOWN MOISTENING TO CONTINUE...MAINLY EMBEDDED SCATTERED LIGHT SHOWERS WILL RESULT...WHICH MAY OBSCURE HIGHER TERRAIN FAVORING AREAS SOUTH OF HIGHWAY 60 NEXT 12 HOURS. IN ADDITION...DISTURBANCE PASSING THROUGH GREAT BASIN AND CENTRAL ROCKIES MAY RESULT IN ISOLD -RASN OR EVEN A SHORT LIVED THUNDERSTORM NEAR THE FOUR CORNERS AND THE NORTHWEST MTS AND MAY RESULT IN BRIEF MT OBSCURATION THRU 12Z SUNDAY. 00Z NAM12 AND LATEST RUC INDICATE SOME LOW/MID LEVEL MOISTURE MAY MAKE A RUN UP THE RGV POSSIBLY REACHING KABQ BY 12Z SUNDAY...THEREFORE MORE WIDESPREAD MT OBSCURATION POSSIBLE BUT CIGS MAY REMAIN VFR. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 57 27 58 27 / 10 5 5 0 DULCE........................... 53 19 54 17 / 20 5 5 0 CUBA............................ 57 24 56 22 / 10 0 5 0 GALLUP.......................... 56 22 55 19 / 10 5 5 0 EL MORRO........................ 52 20 52 18 / 10 5 0 0 GRANTS.......................... 59 24 59 21 / 10 0 0 0 QUEMADO......................... 58 29 57 25 / 5 5 0 0 GLENWOOD........................ 65 29 65 27 / 10 5 0 0 CHAMA........................... 49 22 49 17 / 20 5 5 0 LOS ALAMOS...................... 54 32 53 30 / 10 5 0 0 PECOS........................... 54 32 55 29 / 5 0 0 0 CERRO/QUESTA.................... 53 21 53 19 / 5 5 0 0 RED RIVER....................... 46 19 47 15 / 5 5 5 0 ANGEL FIRE...................... 50 21 51 15 / 5 5 5 0 TAOS............................ 55 20 55 15 / 5 5 0 0 MORA............................ 56 28 56 25 / 5 5 0 0 ESPANOLA........................ 61 26 60 25 / 5 0 0 0 SANTA FE........................ 55 32 55 28 / 5 5 0 0 SANTA FE AIRPORT................ 58 28 57 27 / 5 0 0 0 ALBUQUERQUE FOOTHILLS........... 60 35 59 33 / 5 0 0 0 ALBUQUERQUE HEIGHTS............. 60 37 60 35 / 5 0 0 0 ALBUQUERQUE VALLEY.............. 63 34 62 31 / 5 0 0 0 ALBUQUERQUE WEST MESA........... 62 34 61 32 / 5 0 0 0 LOS LUNAS....................... 63 29 62 26 / 5 0 0 0 RIO RANCHO...................... 61 34 60 32 / 5 0 0 0 SOCORRO......................... 68 34 67 31 / 10 0 0 0 SANDIA PARK/CEDAR CREST......... 59 33 58 31 / 10 0 0 0 TIJERAS......................... 61 33 59 31 / 10 0 0 0 MORIARTY/ESTANCIA............... 61 24 60 21 / 5 0 0 0 CLINES CORNERS.................. 58 31 58 30 / 5 0 0 0 GRAN QUIVIRA.................... 60 34 60 31 / 10 5 0 0 CARRIZOZO....................... 64 35 65 30 / 20 5 0 0 RUIDOSO......................... 58 37 60 35 / 20 5 5 0 CAPULIN......................... 60 31 59 29 / 5 5 5 0 RATON........................... 62 25 62 23 / 0 5 5 0 SPRINGER........................ 63 26 63 24 / 0 5 5 0 LAS VEGAS....................... 60 31 60 27 / 0 5 5 0 CLAYTON......................... 69 37 68 34 / 5 5 5 0 ROY............................. 64 33 63 31 / 0 5 5 0 CONCHAS......................... 69 34 69 30 / 5 5 0 0 SANTA ROSA...................... 69 37 69 32 / 5 5 0 0 TUCUMCARI....................... 71 37 70 30 / 5 5 5 0 CLOVIS.......................... 68 39 69 34 / 20 5 5 0 PORTALES........................ 68 39 70 33 / 20 5 5 5 FORT SUMNER..................... 69 38 70 33 / 10 5 0 0 ROSWELL......................... 74 41 76 35 / 20 5 0 0 PICACHO......................... 70 39 70 34 / 20 5 5 0 ELK............................. 66 41 66 36 / 30 5 5 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1047 PM MST SAT NOV 17 2012 .AVIATION... 06Z TAF CYCLE MID/HIGH LEVEL MOISTURE BOWING NORTHWARD OVER SOUTHERN AND CENTRAL NEW MEXICO...WHILE TOP DOWN MOISTENING TO CONTINUE...MAINLY EMBEDDED SCATTERED LIGHT SHOWERS WILL RESULT...WHICH MAY OBSCURE HIGHER TERRAIN FAVORING AREAS SOUTH OF HIGHWAY 60 NEXT 12 HOURS. IN ADDITION...DISTURBANCE PASSING THROUGH GREAT BASIN AND CENTRAL ROCKIES MAY RESULT IN ISOLD -RASN OR EVEN A SHORT LIVED THUNDERSTORM NEAR THE FOUR CORNERS AND THE NORTHWEST MTS AND MAY RESULT IN BRIEF MT OBSCURATIONS THRU 12Z SUNDAY. 00Z NAM12 AND LATEST RUC INDICATE SOME LOW/MID LEVEL MOISTURE MAY MAKE A RUN UP THE RGV POSSIBLY REACHING KABQ BY 12Z SUNDAY...THEREFORE MORE WIDESPREAD MT OBSCURATION POSSIBLE BUT CIGS MAY REMAIN VFR. && .DISCUSSION...TWO OPPORTUNITIES FOR PRECIPITATION THROUGH NEXT WEEK...THE FIRST ONE THROUGH THE REMAINDER OF THIS WEEKEND AND THE SECOND ONE WED AND WED NIGHT. OTHERWISE DRY WEATHER TO CONTINUE WITH ONLY MINOR DAY TO DAY AND NIGHT TO NIGHT FLUCTUATIONS IN TEMPERATURES. HIGH TEMPERATURES GENERALLY ABOVE NORMAL. NO STRONG WINDS ARE EXPECTED WITH MODERATE BREEZES IN THE E SUN AND WED. SHORT WAVE APPROACHING BAJA CA AND ANOTHER ONE OVER THE W COAST WILL MOVE NE TON AND SUN. ENOUGH LOWER LEVEL MOISTURE SHOULD GET DRAWN N INTO NM TO PRODUCE ISOLATED TO SCATTERED RAIN AND HIGHER ELEVATION SNOW SHOWERS TON INTO SUN...EXCEPT IN THE NE. DEWPOINTS CLIMBING INTO THE 20S AND 30S OVER THE SW ZONES WITH 30S AND 40S DEWPOINTS ALREADY ACROSS THE EASTERN PLAINS. DRYING TREND FOR LATE SUN INTO MON WITH A CHILLY NIGHT SUN NIGHT BUT A NICE MON PM WITH ABOVE NORMAL TEMPS AND PLENTY OF SUNSHINE. A WEAK BACK DOOR FRONT WILL SLOWLY PRESS S ACROSS THE EASTERN PLAINS MON BUT HAVE LITTLE IMPACT ON THE SENSIBLE WEATHER. A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE STATE MON NIGHT THEN SHIFT E TUE. IT WILL BE ANOTHER MILD DAY TUE WITH ABOVE NORMAL TEMPERATURES. MODELS REMAIN CONSISTENT IN BRINGING A LOW FROM OFF BAJA CA TUE TO SOUTHERN NM WED. THEY VARY ON THE EXTENT OF QPF...WITH THE EUROPEAN THE WETTEST FOLLOWED BY THE GFS THEN A MOSTLY DRY CANADIAN MODEL. WILL CONTINUE WITH LOW CHANCES OF RAIN SHOWERS OVER THE SC AND SE ZONES WED AND WED NIGHT. THANKSGIVING DAY AND BLACK FRIDAY LOOKING MIGHTY FINE WITH DRY CONDITIONS...LIGHT WINDS AND ABOVE NORMAL DAYTIME TEMPERATURES. CHJ && .FIRE WEATHER... ABOVE NORMAL TEMPERATURES EXPECTED FOR THE NEXT 7 DAYS WITH HUMIDITIES GENERALLY ABOVE CRITICAL THRESHOLDS. AN UPPER TROUGH WILL BRING SMALL PRECIPITATION CHANCES LATE THIS AFTERNOON THROUGH SUNDAY...AS WELL AS BREEZY CONDITIONS ACROSS THE PLAINS SUNDAY AFTERNOON. A BEAUTIFUL BAROCLINIC LEAF CLOUD MASS IS EVIDENT ON SATELLITE IMAGERY THIS AFTERNOON ASSOCIATED WITH AN OTHERWISE WEAK UPPER LEVEL TROUGH THAT WILL CROSS NEW MEXICO LATE THIS AFTERNOON THROUGH SUNDAY. THE SYSTEM SHOULD PRODUCE MAINLY ISOLATED AND LIGHT RAIN AND SNOW SHOWERS OVER CENTRAL...WESTERN AND SOUTHERN AREAS AS IT CROSSES. A FEW POCKETS OF WETTING PRECIPITATION WILL BE POSSIBLE ON THE WEST SLOPES OF THE SAN JUANS AND ACROSS THE SOUTHERN TIER OF NEW MEXICOS MOUNTAINS. WINDS ALOFT WILL ALSO STRENGTHEN WITH THE PASSING WEATHER SYSTEM...AND A LEE TROUGH IN THE EAST WILL CAUSE WEST AND SOUTHWEST WINDS TO BECOME BREEZY THERE SUNDAY AFTERNOON. IN THE WAKE OF THE WEATHER SYSTEM...A WEAK COLD FRONT WILL SAG SOUTHWARD THROUGH THE STATE MONDAY. AFTER HIGH TEMPERATURES A FEW TO 14 DEGREES ABOVE NORMAL THIS WEEKEND...HIGHS WILL TREND DOWNWARD A FEW DEGREES MONDAY AND ESPECIALLY TUESDAY. NONETHELESS...READINGS WILL REMAIN 4 TO 11 DEGREES ABOVE NORMAL ON TUESDAY...BEFORE WARMING SLIGHTLY WEDNESDAY. THE GFS AND ECMWF CONTINUE TO AGREE ON A WEAK UPPER LEVEL TROUGH TO EJECT FROM THE BAJA ACROSS NORTHERN MEXICO AND SOUTHERN NEW MEXICO TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AHEAD OF THE SYSTEM A MOIST LOW LEVEL RETURN FLOW OUT OF THE SOUTHEAST SHOULD ENHANCE MOISTURE ALONG AND EAST OF THE CENTRAL MOUNTAINS. THE SYSTEM MAY FIND ENOUGH MOISTURE FOR A SLIGHT CHANCE OF RAIN SHOWERS IN SOUTHERN AND EASTERN NM...AND SOME OF THESE SHOWERS MAY EXTEND AS FAR NORTH AS THE MANZANO AND GALLINAS MOUNTAINS AND SOUTHERN PARTS OF THE EAST CENTRAL PLAINS. THE LOW LEVEL MOISTURE TAP WITH THE SYSTEM WILL PROBABLY BE TOO SHALLOW FOR MORE THAN SPOTTY WETTING PRECIPITATION. ANOTHER WEAK COLD FRONT WILL SAG SOUTHWARD THROUGH THE FORECAST AREA ON THURSDAY IN THE WAKE OF THE PASSING WAVE... CAUSING TEMPERATURES TO TREND SLIGHTLY COOLER THURSDAY AND FRIDAY. AFTER GOOD TO EXCELLENT VENTILATION IN MOST LOCATIONS OVER THE WEEKEND...POOR VENTILATION WILL SPREAD ACROSS CENTRAL AND WESTERN PARTS OF THE FORECAST AREA FROM THE WEST DURING THE FIRST HALF OF THE COMING WORK WEEK. DURING THE LATTER HALF OF THE WEEK THE POOR VENTILATION MAY BE COME EVEN MORE WIDESPREAD...EXPANDING TO INCLUDE THE EASTERN PLAINS BY FRIDAY. 44 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
247 AM EST SUN NOV 18 2012 .SYNOPSIS... THROUGH EARLY NEXT WEEK...STRONG HIGH PRESSURE WILL EXTEND ACROSS MUCH OF THE EASTERN US...WHILE A WEAK LOW PRESSURE SYSTEM WILL MEANDER OFF THE SOUTHEAST COAST. && .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 930 PM SATURDAY... REST OF TONIGHT: COMPLEX PATTERN ACROSS THE SOUTHEAST AND MIDATLANTIC THIS EVENING... AND THE MAIN FORECAST CONCERN REMAINS THE CHANCE FOR RAIN OVERNIGHT. SURFACE HIGH PRESSURE REMAINS QUITE STRONG (OVER 1038 MB) CENTERED OVER THE ST LAWRENCE VALLEY AND EXTENDING SOUTHWARD THROUGH NC... WHILE A STRENGTHENING LOW LEVEL FRONTAL ZONE AND DEVELOPING LOW PRESSURE OFF THE SOUTHEAST COAST IS EXPECTED TO GENERATE A TIGHTENING MSLP GRADIENT OVERNIGHT... ESPECIALLY OVER THE SRN AND ERN CWA. CONVECTION WAS WIDESPREAD JUST OFF THE CAROLINA COAST THIS AFTERNOON... AND WHILE THE INTENSITY OF THIS RAIN HAS DECREASED... IT REMAINS IN PLACE JUST OFF THE SC AND SRN NC COAST. THE 12Z 4-KM WRF-ARW AND WRF-NMM DID A SUBPAR JOB IN DEPICTING THIS RAIN... ALTHOUGH THE 18Z LOCAL WRF-ARW DID BETTER AND IS SIMILAR TO THE LATEST HRRR OUTPUT... WHICH SHOWS THE BULK OF THE RAIN SHIELD HOLDING OVER AND JUST OFF THE SC COAST WITH JUST PATCHY RAIN SPREADING INTO OUR FAR SOUTHEAST COUNTIES OVERNIGHT. THIS ALSO APPEARS IN LINE WITH THE LATEST SREF PROBABILITIES OF MEASURABLE RAIN... WHICH KEEPS CHANCES UNDER 30 PERCENT IN THE SOUTHEAST TONIGHT. BASED ON THIS AND MODEL AGREEMENT ON ACCELERATING LOW LEVEL MOISTURE TRANSPORT TONIGHT AND THE PACE AT WHICH THE LOWER STRATUS AND SMALLER DEW POINT DEPRESSION AIR IS SPREADING WESTWARD INTO SOUTHEAST NC... WILL HOLD ONTO A SLIGHT CHANCE OF RAIN TONIGHT IN THIS AREA. FORECAST SOUNDINGS DEPICT A FAIRLY DEEP (3000-4000 FT THICK) SURFACE-BASED STABLE LAYER... BUT CLOSE EXAMINATION REVEALS A VERY SHALLOW (FEW HUNDRED FEET) SLIGHTLY MIXED LAYER RIGHT AT THE SURFACE... REASONABLE CONSIDERING HOW THE WINDS THROUGHOUT THE LOWEST FEW THOUSAND FEET WILL BE STRENGTHENING AT ONCE. WILL KEEP WINDS UP OVERNIGHT WITH PERIODIC GUSTS. THE LOW LEVEL STIRRING WILL HOLD TEMPS UP... AND EXPECT LOWS OF 38-48. -GIH SUNDAY AND SUNDAY NIGHT...THE MID LEVEL ANTI-CYCLONE OFF THE SOUTHERN NEW ENGLAND COAST AND THE NE FL/SRN GA COAST WILL MAINTAIN A DEEP ELY FLOW INTO CENTRAL NC WITH SPEED CONFLUENCE NOTED OVER THE REGION DURING THE AFTERNOON-EARLY EVENING HOURS. THE LIFT SUPPLIED BY THIS CONFLUENCE WILL GENERATE AREAS OF LIGHT RAIN...MAINLY ALONG THE I-95 CORRIDOR. FARTHER WEST...LIFT WEAKER TO NON-EXISTENT. THIS WILL LEAD TO PRECIP CHANCES RANGING FROM LIKELY IN THE EAST TO LOW END CHANCE-SLIGHT CHANCE IN THE FAR WEST LATE SUNDAY INTO SUNDAY NIGHT. EXPECT A NARROW DIURNAL TEMP RANGE SUNDAY SUNDAY NIGHT DUE TO CLOUDS AND PRECIP. MAX TEMPS LOW-MID 50S SUNDAY.MIN TEMPS SUNDAY NIGHT AROUND 40 NW TO UPPER 40S/NEAR 50 E-SE. -WSS && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 245 AM SUNDAY... MONDAY NIGHT: SURFACE LOW OFF THE NC COAST CONTINUES TO MIGRATE SLOWLY TO THE NE WITH RIDGING OVER NC AND SURFACE HIGH OVER NEW ENGLAND. OFFSHORE LOW BECOMES MORE VERTICALLY STACKED WITH THE UPPER LEVEL LOW OFFSHORE AND RIDGING OVER NC. CENTRAL NC SHOULD REMAIN DRY OVERNIGHT...WITH THE BEST CHANCES FOR LINGERING PRECIP ALONG THE NC COAST. WINDS WILL BE STRONGEST FARTHER EAST...5 TO 10 KTS. LOWS EXPECTED IN THE MID 40S. TUESDAY THROUGH WEDNESDAY: SURFACE HIGH PRESSURE REMAINS IN PLACE AS AN UPPER LEVEL TROUGH MOVES IN FROM THE WEST...WITH A S/W AHEAD OF THE MAIN TROUGH AXIS. ALTHOUGH THERE IS STRONG VORTICITY AT THE UPPER LEVELS WITH THE TROUGH AXIS...SURFACE HIGH PRESSURE...WITH ITS ASSOCIATED STABILITY AND SUBSIDENCE IN THE LOWER LEVELS SHOULD KEEP THE CHANCES FOR PRECIP LOW. THERE IS STILL SOME DIFFERENCE BETWEEN THE MODELS WITH REGARD TO PRECIP GENERATION WITH THE INITIAL S/W...AS THE 12Z ECMWF GENERATES PRECIP WHILE THE 00Z GFS REMAINS DRY THROUGHOUT. AS SUCH...WILL KEEP SLIGHT CHANCE FOR RAIN TUESDAY AND TUESDAY NIGHT AND A DRY FORECAST FOR WEDNESDAY...WITH OVERCAST SKIES EXPECTED TUESDAY AND TUESDAY NIGHT. STRONGEST WINDS IN THE EAST WHERE THE PRESSURE GRADIENT BETWEEN THE SURFACE HIGH AND OFFSHORE LOW IS THE GREATEST. HIGHS NEAR NORMAL...IN THE UPPER 50S TO LOW 60S TUESDAY AND WEDNESDAY WITH LOWS TUESDAY NIGHT IN THE LOW TO MID 40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... AS OF 245 AM SUNDAY... SKIES WILL START CLEARING WEDNESDAY AFTERNOON AS THE UPPER LEVEL TROUGH MOVES OFFSHORE. AS THE TROUGH MOVES OFFSHORE THE SURFACE LOW OFF THE NC COAST WILL STRENGTHEN. THE LOW SHOULD BE FAR ENOUGH OFFSHORE TO KEEP PRECIP OUT OF THE AREA. WITH THE RIDGE BUILDING INTO THE AREA AT THE SURFACE AND ALOFT THURSDAY MORNING AND REMAINING OVER CENTRAL NC THROUGH FRIDAY...WILL KEEP THE FORECAST DRY THROUGH THAT PERIOD. HIGH TEMPS WILL BE IN THE MID 60S THURSDAY AND FRIDAY WITH LOWS WEDNESDAY...THURSDAY...AND FRIDAY NIGHTS RANGING FROM THE MID 30S TO LOW 40S. THERE ARE LARGE DIFFERENCES BETWEEN THE 12Z ECMWF AND 00Z GFS FRIDAY AND SATURDAY WITH REGARD TO WHETHER AN UPPER LEVEL LOW AND ASSOCIATED TROUGH (ECMWF) WILL DEVELOP AND DIG INTO THE AREA FRIDAY NIGHT OR WHETHER THE PATTERN ALOFT WILL REMAIN MORE ZONAL FRIDAY NIGHT...WITH A WEAKER TROUGH DEVELOPING TO THE WEST LATE SATURDAY (GFS). PRECIP CHANCES WILL DEPEND UPON THE TIMING AND STRENGTH OF THIS SYSTEM. WITH THE GREAT DEAL OF UNCERTAINTY IN THE MODELS...CONFIDENCE IN THE PRECIP FORECAST FRIDAY AND SATURDAY IS LOW...BUT FOR NOW WILL KEEP IT DRY. HIGHS ON SATURDAY WILL ALSO BE IMPACTED IF PRECIP DOES DEVELOP...BUT STAYING CONSISTENT WITH THE DRY FORECAST...ANTICIPATE HIGHS IN THE UPPER 50S TO LOW 60S. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 125 AM SUNDAY... THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE OVER THE NORTHEAST AND A FRONTAL ZONE AND DEVELOPING AREA OF LOW PRESSURE OFF THE SOUTHEAST US COAST WILL PRODUCE STRONG NORTHEASTERLY LOW LEVEL FLOW THAT WILL RESULT IN BOTH THE EXPANSION OF 1000-2000 FT (MVFR) CEILINGS THIS MORNING AND BREEZY AND GUSTY NE SURFACE WINDS THROUGH THE TAF PERIOD. THE CEILINGS MAY BRIEFLY LOWER TO IFR RANGE...JUST BELOW 1000 FT...FOR A FEW HOURS THIS MORNING AT KRWI/KRDU...BUT PREDOMINATELY MVFR CEILINGS ARE EXPECTED. THE OFFSHORE AREA OF LOW PRESSURE WILL ALSO RESULT IN PATCHY LIGHT RAIN TODAY AND TONIGHT MAINLY AT KFAY/KRWI/KRDU...AS IT MEANDERS OFF THE SOUTHEAST COAST. LOOKING AHEAD: WHILE THE WINDS WILL GRADUALLY LESSEN BY MON...OWING TO A STEADY WEAKENING OF THE SURFACE HIGH OVER THE NORTHEAST AND CONSEQUENT RELAXATION OF THE MSL PRESSURE GRADIENT...THE WEAKENED NORTHEASTERLY FLOW WILL REMAIN MOIST AND MAINTAIN A HIGH PROBABILITY OF MVFR RANGE CEILINGS THROUGH EARLY TUE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...HARTFIELD/WSS SHORT TERM...KC LONG TERM...KC AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
130 AM EST SUN NOV 18 2012 .SYNOPSIS... THROUGH EARLY NEXT WEEK...STRONG HIGH PRESSURE WILL EXTEND ACROSS MUCH OF THE EASTERN US...WHILE A WEAK LOW PRESSURE SYSTEM WILL MEANDER OFF THE SOUTHEAST COAST. && .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 930 PM SATURDAY... REST OF TONIGHT: COMPLEX PATTERN ACROSS THE SOUTHEAST AND MIDATLANTIC THIS EVENING... AND THE MAIN FORECAST CONCERN REMAINS THE CHANCE FOR RAIN OVERNIGHT. SURFACE HIGH PRESSURE REMAINS QUITE STRONG (OVER 1038 MB) CENTERED OVER THE ST LAWRENCE VALLEY AND EXTENDING SOUTHWARD THROUGH NC... WHILE A STRENGTHENING LOW LEVEL FRONTAL ZONE AND DEVELOPING LOW PRESSURE OFF THE SOUTHEAST COAST IS EXPECTED TO GENERATE A TIGHTENING MSLP GRADIENT OVERNIGHT... ESPECIALLY OVER THE SRN AND ERN CWA. CONVECTION WAS WIDESPREAD JUST OFF THE CAROLINA COAST THIS AFTERNOON... AND WHILE THE INTENSITY OF THIS RAIN HAS DECREASED... IT REMAINS IN PLACE JUST OFF THE SC AND SRN NC COAST. THE 12Z 4-KM WRF-ARW AND WRF-NMM DID A SUBPAR JOB IN DEPICTING THIS RAIN... ALTHOUGH THE 18Z LOCAL WRF-ARW DID BETTER AND IS SIMILAR TO THE LATEST HRRR OUTPUT... WHICH SHOWS THE BULK OF THE RAIN SHIELD HOLDING OVER AND JUST OFF THE SC COAST WITH JUST PATCHY RAIN SPREADING INTO OUR FAR SOUTHEAST COUNTIES OVERNIGHT. THIS ALSO APPEARS IN LINE WITH THE LATEST SREF PROBABILITIES OF MEASURABLE RAIN... WHICH KEEPS CHANCES UNDER 30 PERCENT IN THE SOUTHEAST TONIGHT. BASED ON THIS AND MODEL AGREEMENT ON ACCELERATING LOW LEVEL MOISTURE TRANSPORT TONIGHT AND THE PACE AT WHICH THE LOWER STRATUS AND SMALLER DEW POINT DEPRESSION AIR IS SPREADING WESTWARD INTO SOUTHEAST NC... WILL HOLD ONTO A SLIGHT CHANCE OF RAIN TONIGHT IN THIS AREA. FORECAST SOUNDINGS DEPICT A FAIRLY DEEP (3000-4000 FT THICK) SURFACE-BASED STABLE LAYER... BUT CLOSE EXAMINATION REVEALS A VERY SHALLOW (FEW HUNDRED FEET) SLIGHTLY MIXED LAYER RIGHT AT THE SURFACE... REASONABLE CONSIDERING HOW THE WINDS THROUGHOUT THE LOWEST FEW THOUSAND FEET WILL BE STRENGTHENING AT ONCE. WILL KEEP WINDS UP OVERNIGHT WITH PERIODIC GUSTS. THE LOW LEVEL STIRRING WILL HOLD TEMPS UP... AND EXPECT LOWS OF 38-48. -GIH SUNDAY AND SUNDAY NIGHT...THE MID LEVEL ANTI-CYCLONE OFF THE SOUTHERN NEW ENGLAND COAST AND THE NE FL/SRN GA COAST WILL MAINTAIN A DEEP ELY FLOW INTO CENTRAL NC WITH SPEED CONFLUENCE NOTED OVER THE REGION DURING THE AFTERNOON-EARLY EVENING HOURS. THE LIFT SUPPLIED BY THIS CONFLUENCE WILL GENERATE AREAS OF LIGHT RAIN...MAINLY ALONG THE I-95 CORRIDOR. FARTHER WEST...LIFT WEAKER TO NON-EXISTENT. THIS WILL LEAD TO PRECIP CHANCES RANGING FROM LIKELY IN THE EAST TO LOW END CHANCE-SLIGHT CHANCE IN THE FAR WEST LATE SUNDAY INTO SUNDAY NIGHT. EXPECT A NARROW DIURNAL TEMP RANGE SUNDAY SUNDAY NIGHT DUE TO CLOUDS AND PRECIP. MAX TEMPS LOW-MID 50S SUNDAY.MIN TEMPS SUNDAY NIGHT AROUND 40 NW TO UPPER 40S/NEAR 50 E-SE. -WSS && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 310 PM SATURDAY... MONDAY AND MONDAY NIGHT...WHILE MID LEVEL ANTI-CYCLONE WILL REMAIN NEARLY STATIONARY OFF THE NORTHERN MID ATLANTIC COAST...THE AREA OF LOW PRESSURE OFF THE NE FL COAST WILL LIFT TO THE ENE. THIS MOVEMENT OF THE LOW WILL CAUSE THE MID LEVEL FLOW OVER CENTRAL NC TO WEAKEN AND BECOME MORE NELY. THUS...EXPECT RAIN CHANCES TO DWINDLE MONDAY WITH A SLIGHT CHANCE POP CONFINED TO THE EASTERN HALF BY AFTERNOON....AND LITTLE IF ANY RAIN EXPECTED MONDAY NIGHT. MODEL GUIDANCE DIFFERS AS TO THE AMOUNT OF DECREASING CLOUDINESS TO OCCUR WHICH LEADS TO DISCREPANCIES IN THE TEMP GUIDANCE MONDAY. LATEST NAM MORE EMPHATIC WITH ITS CLEARING TREND WHICH TRANSLATES TO WARMER AFTERNOON TEMPS. THE 12Z ECMWF WEAKEN OFFERS A SCENARIO SOMEWHAT BUT NOT AS EMPHATIC WITH THE AMOUNT OF DRYING. GFS MAINTAINS A SATURATED AIR MASS THROUGH THE PERIOD. PLACED A BIT MORE EMPHASIS TOT EH GFS AS POTENTIAL EXIST FOR MOISTURE TO BE TRAPPED BELOW MID LEVEL SUBSIDENCE INVERSION. THUS WILL FAVOR HIGH TEMPS MONDAY TOWARD THE COOLER GFS MOS. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 310 PM SATURDAY... BRIEF S/W RIDING ALOFT AT THE START OF THE MEDIUM RANGE PERIOD IS EXPECTED TO QUICKLY SHIFT TO THE EAST OF THE AREA ON TUESDAY AS A PAIR OF MID/UPPER LEVEL DISTURBANCES USHER IN A RETURN TO POSSIBLE UNSETTLE WEATHER. HOWEVER... AT THE SURFACE/LOW LEVELS OF THE ATMOSPHERE EXPECT A GENERALLY NORTHERLY FLOW WILL CONTINUE... WITH THE AFOREMENTIONED SURFACE LOW PRESSURE EXPECTED TO REMAIN OFFSHORE OR SLOWLY LIFT NORTH OR NORTHEASTWARD. MODELS ARE CONTINUING TO STRUGGLE THOUGH WRT POSSIBLE LIGHT RAIN FOR TUESDAY INTO TUESDAY NIGHT. THE DIFFERENCES APPEAR TO BE TIED TO THE STRENGTH IN THE MID/UPPER LEVEL RIDGING AND APPROACHING NEXT SET OF IMPULSES ALOFT. FOR NOW WILL TREND THE FORECAST TO THE DRIER SIDE OF GUIDANCE (CLOSER TO THE ECMWF AND NAM). FOR NOW WILL LOWER POPS TO SLIGHT CHANCE AREAWIDE. HOWEVER... STILL EXPECT SKIES WILL BE AT LEAST MOSTLY CLOUDY WHICH WILL STILL HELP SUPPRESS HIGH TEMPS DESPITE LOW LEVEL THICKNESS VALUES AROUND NORMAL. WILL GO WITH HIGH TEMPS IN THE UPPER 50S TO AROUND 60... A BIT BELOW NORMAL. HOWEVER... IF THE RAIN DOES MATERIALIZE EXPECTED TEMPS WOULD BE A GOOD 5 TO 10 DEGREES COOLER AT LEAST THAN CURRENT FORECAST. LOW TUESDAY NIGHT/WEDNESDAY MORNING ARE EXPECTED TO BE IN THE LOWER TO MID 40S... WITH SKIES BEGINNING TO CLEAR AT BIT (MORE SO WEST) AS THE FIRST DISTURBANCE BEGINS TO PUSH TO THE EAST OF THE AREA. MID/UPPER LEVEL TROUGH AXIS IS EXPECTED TO AMPLIFY ACROSS THE AREA AGAIN ON WEDNESDAY AS A SECOND S/W TROUGH ROTATES THROUGH THE AREA ON WEDNESDAY/WEDNESDAY NIGHT. HOWEVER... DESPITE THE DEEPENING TROUGH... BEST LIFT AND MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA. THUS... WITH AFTERNOON LOW LEVEL THICKNESS VALUES AROUND NORMAL AND SKIES BECOMING PARTLY SUNNY LATE IN THE DAY EXPECT HIGH TEMPS TO BE IN THE UPPER 50S TO LOWER 60S. LOWS WITH CLEARING SKIES ON THURSDAY MORNING ARE EXPECTED TO RANGE FROM THE MID 30S TO LOWER 40S. THURSDAY THROUGH SATURDAY: RIDGING ALOFT IS EXPECTED TO BUILD ACROSS THE AREA DURING THIS TIMEFRAME... WHILE A NORTHERN STREAM SYSTEM IS EXPECTED TO MOVE ACROSS THE NORTHERN PORTION OF THE COUNTRY. AT THE SURFACE EXPECT HIGH PRESSURE WILL REMAIN ACROSS THE AREA THROUGH AT LEAST FRIDAY MORNING/AFTERNOON... BEFORE A TRAILING DRY COLD FRONT ASSOCIATED WITH THE NORTHERN STREAM SYSTEM IS EXPECTED TO MOVE THROUGH THE AREA LATE FRIDAY INTO FRIDAY NIGHT. HIGH PRESSURE IS EXPECTED TO BUILD INTO THE AREA BEHIND THE FRONT ON SATURDAY. EXPECT ABOVE NORMAL TEMPS THURSDAY/FRIDAY... WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS ON SATURDAY. EXPECT HIGH TEMPS IN THE 60S THURSDAY/FRIDAY TO UPPER 50S TO AROUND 60 NEXT SATURDAY. LOWS IN THE UPPER 30S TO LOWER 40S... WITH POSSIBLE MID 30S IN THE USUAL RURAL COOL/COLDER AREAS. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 125 AM SUNDAY... THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE OVER THE NORTHEAST AND A FRONTAL ZONE AND DEVELOPING AREA OF LOW PRESSURE OFF THE SOUTHEAST US COAST WILL PRODUCE STRONG NORTHEASTERLY LOW LEVEL FLOW THAT WILL RESULT IN BOTH THE EXPANSION OF 1000-2000 FT (MVFR) CEILINGS THIS MORNING AND BREEZY AND GUSTY NE SURFACE WINDS THROUGH THE TAF PERIOD. THE CEILINGS MAY BRIEFLY LOWER TO IFR RANGE...JUST BELOW 1000 FT...FOR A FEW HOURS THIS MORNING AT KRWI/KRDU...BUT PREDOMINATELY MVFR CEILINGS ARE EXPECTED. THE OFFSHORE AREA OF LOW PRESSURE WILL ALSO RESULT IN PATCHY LIGHT RAIN TODAY AND TONIGHT MAINLY AT KFAY/KRWI/KRDU...AS IT MEANDERS OFF THE SOUTHEAST COAST. LOOKING AHEAD: WHILE THE WINDS WILL GRADUALLY LESSEN BY MON...OWING TO A STEADY WEAKENING OF THE SURFACE HIGH OVER THE NORTHEAST AND CONSEQUENT RELAXATION OF THE MSL PRESSURE GRADIENT...THE WEAKENED NORTHEASTERLY FLOW WILL REMAIN MOIST AND MAINTAIN A HIGH PROBABILITY OF MVFR RANGE CEILINGS THROUGH EARLY TUE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...MWS
AREA FORECAST DISCUSSION
NWS SPOKANE WA
956 PM PST Sat Nov 17 2012 .SYNOPSIS... Through next week expect a progressive and wet weather pattern to return with periods of mountain snow and valley rain this weekend and through next week. Higher snow levels Sunday Night through Tuesday morning will combine with the heaviest expected precipitation in this forecast cycle to produce rises on the areas small stream or creeks...especially for North Idaho. Windy conditions will develop over portions of the Inland Northwest on Monday. && .DISCUSSION... ...Areas of heavy rain...mountain snow...along with windy conditions early next week.... Update...Radar imagery as of 945 pm indicated a large area of rain associated with a cold front from Republic to Moses Lake eastward to near the Washington/Idaho Border. The GFS/NAM/HRRR shows this area of rain moving east through tonight with drier air and downslope flow off the Cascades bringing a drying trend from west to east. The HRRR which has a good handle on this area of rain shows the back edge of the rain passing through Moses Lake around 10 pm, Spokane 1 am, and Sandpoint 3 am. This matches the trends from the NAM well so opted to update the forecast tonight to show these trends in the NDFD grids. However some showers may linger over the mountains of NE Washington and N Idaho Sunday morning after the front passes due to the 850-700mb layer remaining nearly saturated along with upslope flow. No big changes noted on the 00z GFS run concerning the active period expected for early next week with heavy mountain snow along the East Slopes of the Cascades and Northern Mountains, windy weather across portions of the area, along with heavy rain for much of the Inland Northwest. See previous forecast discussion and latest Weather Stories on our home page for more information. JW && .AVIATION... 06Z TAFs: Rain will persist through 08-11z over Eastern Washington and North Idaho as a cold front tracks through the area. Expect lowering cigs and vis into MVFR category with rain this evening. Moist upslope flow over the Spokane/Coeur d`Alene taf sites behind the front is expected to lower cigs into the IFR category through at least the early morning hours on Sunday. We will see a break in the precipitation Sunday morning with another round of rain crossing the Cascades around 00z Monday as a warm front moves in. Good mixing potential on Sunday afternoon may result in gusts up to 20-25 kts for the KGEG, KSFF, KCOE, KPUW and KMWH taf sites. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 37 45 38 42 40 46 / 100 50 100 100 100 80 Coeur d`Alene 37 45 36 42 40 46 / 100 50 90 100 100 80 Pullman 37 47 38 44 42 49 / 100 30 80 70 100 80 Lewiston 40 53 42 50 45 53 / 90 20 60 70 90 70 Colville 37 43 38 41 38 47 / 100 50 100 100 100 80 Sandpoint 37 44 35 41 38 44 / 100 80 90 100 100 100 Kellogg 37 41 34 39 39 44 / 100 80 60 100 100 100 Moses Lake 36 47 39 47 40 49 / 70 10 60 50 70 60 Wenatchee 37 45 38 44 39 47 / 40 20 90 50 70 60 Omak 35 42 37 42 39 45 / 100 30 100 100 70 60 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...High Wind Watch from late Sunday night through Monday evening for Coeur d`Alene Area-Idaho Palouse. Winter Storm Watch from Sunday evening through late Monday night for Northern Panhandle. WA...Winter Storm Watch from Sunday afternoon through Monday evening for East Slopes Northern Cascades. High Wind Watch from late Sunday night through Monday evening for Lower Garfield and Asotin Counties-Moses Lake Area- Northeast Blue Mountains-Northeast Mountains-Okanogan Highlands-Spokane Area-Upper Columbia Basin-Washington Palouse. Winter Storm Watch from Sunday evening through late Monday night for Northeast Mountains-Okanogan Highlands. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
828 PM PST Sat Nov 17 2012 .SYNOPSIS... Through next week expect a progressive and wet weather pattern to return with periods of mountain snow and valley rain this weekend and through next week. Higher snow levels Sunday Night through Tuesday morning will combine with the heaviest expected precipitation in this forecast cycle to produce rises on the areas small stream or creeks...especially for North Idaho. Windy conditions will develop over portions of the Inland Northwest on Monday. && .DISCUSSION... ...Areas of heavy rain...mountain snow...along with windy conditions early next week.... Update...Radar imagery as of 8 pm indicated a large area of rain associated with a cold front from Omak to Moses Lake eastward to near the Washington/Idaho Border. The GFS/NAM/HRRR shows this area of rain moving east through tonight with drier air and downslope flow off the Cascades bringing a drying trend from west to east. The HRRR which has a good handle on this area of rain shows the back edge of the rain passing through Moses Lake around 10 pm, Spokane 1 am, and Sandpoint 3 am. This matches the trends from the NAM well so opted to update the forecast tonight to show these trends in the NDFD grids. However some showers may linger over the mountains of NE Washington and N Idaho Sunday morning after the front passes due to the 850-700mb layer remaining nearly saturated along with upslope flow. No big changes noted on the 00z GFS run concerning the active period expected for early next week with heavy mountain snow along the East Slopes of the Cascades and Northern Mountains, windy weather across portions of the area, along with heavy rain for much of the Inland Northwest. See previous forecast discussion and latest Weather Stories on our home page for more information. JW && .AVIATION... 00Z TAFs: A cold front is pushing into coastal Washington this evening. Moist isentropic accent ahead of the front will result in light rain at all taf sites this evening. Rainfall will diminish from west to east late this evening into tonight as the front pushes east of the region. Expect lowering cigs and vis into MVFR category with rain this evening. Moist upslope flow over the Spokane/Coeur d`Alene taf sites behind the front is expected to lower cigs into the IFR category through at least the early morning hours on Sunday. We will see a break in the precipitation Sunday morning with rain returning Sunday afternoon as a warm front pushes in. Good mixing potential on Sunday afternoon may result in a gusts up to 20-25 kts for the KGEG, KSFF, KCOE, KPUW and KMWH taf sites. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 37 45 38 42 40 46 / 100 50 100 100 100 80 Coeur d`Alene 37 45 36 42 40 46 / 100 50 90 100 100 80 Pullman 37 47 38 44 42 49 / 100 30 80 70 100 80 Lewiston 40 53 42 50 45 53 / 90 20 60 70 90 70 Colville 37 43 38 41 38 47 / 100 50 100 100 100 80 Sandpoint 37 44 35 41 38 44 / 100 80 90 100 100 100 Kellogg 37 41 34 39 39 44 / 100 80 60 100 100 100 Moses Lake 36 47 39 47 40 49 / 70 10 60 50 70 60 Wenatchee 37 45 38 44 39 47 / 40 20 90 50 70 60 Omak 35 42 37 42 39 45 / 100 30 100 100 70 60 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...High Wind Watch from late Sunday night through Monday evening for Coeur d`Alene Area-Idaho Palouse. Winter Storm Watch from Sunday evening through late Monday night for Northern Panhandle. WA...Winter Storm Watch from Sunday afternoon through Monday evening for East Slopes Northern Cascades. High Wind Watch from late Sunday night through Monday evening for Lower Garfield and Asotin Counties-Moses Lake Area- Northeast Blue Mountains-Northeast Mountains-Okanogan Highlands-Spokane Area-Upper Columbia Basin-Washington Palouse. Winter Storm Watch from Sunday evening through late Monday night for Northeast Mountains-Okanogan Highlands. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
510 PM CST MON NOV 19 2012 .SHORT TERM... 250 PM CST MON NOV 19 2012 MAIN FORECAST CONCERN IS ON SKY CONDITIONS TONIGHT AND THEN TEMPERATURES THROUGH THE REMAINDER OF THE PERIOD. 18Z WATER VAPOR IMAGERY SHOWS A SHORTWAVE OVER NORTHERN ILLINOIS/EASTERN IOWA...WHILE ANOTHER SHORTWAVE WAS LOCATED OVER NORTH DAKOTA. THIS LEAD SHORTWAVE IS SPREADING THE SCATTERED SHOWERS INTO EASTERN WISCONSIN. MEANWHILE...VISIBLE SATELLITE IMAGERY SHOWS BACK EDGE OF CLOUDS EXTENDING FROM NEAR THE TWIN CITIES TO CHARLES CITY IOWA AND MOVING STEADILY EASTWARD. 19.12Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD WITH THE OVERALL PATTERN. STILL SOME TIMING DIFFERENCES WITH FRONT THE MOVES THROUGH THE AREA THANKSGIVING DAY...BUT LOOK TO HAVE MINIMAL IMPACT ON THE SENSIBLE WEATHER. IN THE NEAR TERM...LEAD SHORTWAVE WILL PUSH NORTHEAST AWAY FROM THE AREA THIS EVENING...WITH CLEARING SKIES IN ITS WAKE ACROSS MAINLY THE WESTERN COUNTIES. HOWEVER...SECOND WAVE DROPPING FROM THE NORTHERN PLAINS WILL PUSH A COLD FRONT TOWARDS THE AREA THIS EVENING. 19.12Z NAM/19.16Z RAP BUFKIT SOUNDINGS INDICATING THE DEVELOPMENT OF STRATUS ACROSS THE AREA TONIGHT...THIS ALSO IN LINE WITH INCREASING PROBABILITIES IN THE 19.09Z SREF. THUS AFTER SOME CLEARING EARLY THIS EVENING IN THE WEST...EXPECT STRATUS TO DEVELOP THROUGH THE OVERNIGHT HOURS BEFORE DRIER AIR ADVECTS INTO THE AREA AFTER 09Z-12Z. DID INCREASE SKY COVER TONIGHT FROM PREVIOUS FORECAST. STRATUS WILL BREAK UP TUESDAY MORNING..WITH ATTENTION THEN TURNING TO UPPER RIDGE BUILDING IN AND ITS AFFECT ON TEMPERATURES. 925MB TEMPERATURES CLIMB FROM 7 TO 9 DEGREES ON TUESDAY...TO 10 TO 13 DEGREES ON WEDNESDAY. WITH PLENTY OF SUNSHINE EXPECTED ALONG WITH MIXING TO BETWEEN 925MB-950MB...EXPECT TEMPERATURES TO WARM TO WELL ABOVE GUIDANCE VALUES. 850MB TEMPERATURE ANOMALIES ARE NEARLY 2 STANDARD DEVIATIONS ABOVE NORMAL ON WEDNESDAY AND THUS EXPECT TEMPERATURES NEAR RECORDS IN SOME LOCATIONS (SEE CLIMATE SECTION BELOW FOR A LIST OF RECORDS). WITH A CONTINUED SOUTHERLY FLOW WEDNESDAY NIGHT...MILD TEMPERATURES WILL CONTINUE WITH LOWS ONLY IN THE 40S. ON THURSDAY...RIDGE BREAKS DOWN AS SHORTWAVE ROTATES ACROSS THE PLAINS PUSHING A COLD FRONT ACROSS THE AREA THROUGH THE DAY. STILL SOME SLIGHT TIMING DIFFERENCES BETWEEN THE MODELS...BUT THE COLDER AIR LOOKS TO LAG BEHIND THE FRONT...NOT ARRIVING UNTIL THURSDAY NIGHT. A PLUME OF LOW LEVEL MOISTURE AHEAD OF IT STREAMING INTO SOUTHWEST AND CENTRAL WISCONSIN. 19.12Z GFS IS SHOWING 100 TO 150 J/KG OF MOST UNSTABLE CAPE WITH THE MOISTURE PLUME AND DOES GENERATE SOME SHOWERS. DID KEEP THE LOWER END PROBABILITIES WITH THIS FEATURE ACROSS MAINLY THE SOUTHEASTERN HALF OF THE FORECAST AREA. BY THURSDAY NIGHT FRONT WILL BE EAST OF THE AREA..WITH THE UPPER LEVEL TROUGH SWINGING THROUGH NORTHERN WISCONSIN. DID ADD LOWER END PRECIPITATION CHANCES TO THE FAR NORTH FOR A CHANCE OF RAIN/SNOW. .LONG TERM... 250 PM CST MON NOV 19 2012 SYSTEM DEPARTS ON FRIDAY...WITH CYCLONIC FLOW ACROSS THE AREA. TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS MAINLY IN THE 30S. MAIN PRECIPITATION CHANCE WILL BE ACROSS THE FAR NORTH. OTHERWISE...REMAINDER OF THE PERIOD WILL BE DOMINATED BY SEASONAL TO BELOW NORMAL TEMPERATURES. BEST CHANCE FOR ANY PRECIPITATION LOOKS BE ON MONDAY...BUT MODELS SHOWING SOME DIFFERENCES WITH A DEVELOPING TROUGH ACROSS THE CENTRAL CONUS. 19.12Z ECMWF SHOWS THIS FEATURE WITH CYCLOGENESIS OCCURRING...WHILE THE GFS KEEPS FLOW MORE ZONAL. IF THE ECMWF DOES VERIFY WILL HAVE TO WATCH THIS SYSTEM FOR PERIODS BEYOND MONDAY. && .AVIATION... 510 PM CST MON NOV 19 2012 CONCERN TONIGHT IS FOR IFR/MVFR CIGS/VSBYS DEVELOPING. THE SHORTWAVE FROM EARLY THIS MORNING BROUGHT SOME LIGHT RAIN WITH ONLY MINOR ACCUMULATIONS...BUT IT DID SERVE TO HELP ADD SOME MOISTURE TO THE NEAR SFC LAYER. IN ADDITION...RAP13/NAM12 925 MB RH FIELDS CONTINUE TO POINT TO ADVECTING MOISTURE NORTHEAST ACROSS THE LOCAL AREA TONIGHT...WHICH WOULD BE TRAPPED UNDER AN INVERSION AS SHOWN BY THE BUFKIT SOUNDINGS. LATEST SATELLITE IMAGERY AND SFC OBS ALREADY INDICATE SOME STRATUS DEVELOPMENT ON THE BACKSIDE OF THE MAIN AREA OF CLOUDS...OVER NORTHEAST IA WITH 1.5-2.5 KFT CIGS. TRAJECTORY AND MODEL TRENDS WOULD FAVOR THESE CONDITIONS AT KLSE MORE THAN KRST. WILL CONTINUE PERIOD OF MVFR TO IFR FOR KLSE...WITH PERHAPS A SHORT PERIOD OF MVFR FOR KRST. WILL HAVE TO MONITOR TRENDS CLOSELY AND ADJUST AS NECESSARY. CLOUDS SHOULD CLEAR LATE MORNING WITH THE EXITING OF A SFC FRONT AND SUBSIDENCE A LOFT. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 6AM-6AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 250 PM CST MON NOV 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RABERDING LONG TERM....RABERDING AVIATION.....RIECK CLIMATE......JONES/DB/AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1121 AM CST SUN NOV 18 2012 .SHORT TERM...THROUGH TUESDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TONIGHT INTO MONDAY AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A DEEP TROUGH FROM JUST OFF THE COAST OF BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST...AND SOUTHWEST FLOW FROM THE DESERT SOUTHWEST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. WITHIN THIS SOUTHWEST FLOW...SHORTWAVES OF NOTE ARE ALONG THE UTAH/COLORADO BORDER AND IN NORTHWEST MINNESOTA. DPVA AHEAD OF THIS LATTER SHORTWAVE COMBINED WITH 295-300K ISENTROPIC LIFT PRODUCED SHOWERS ACROSS NORTHEAST MINNESOTA. THE 295K ISENTROPIC LIFT ALSO EXTENDED SOUTHWEST FROM NORTHEAST MINNESOTA INTO CENTRAL IOWA...AND ALONG THIS ZONE IS A BAND OF STRATUS WITH CEILINGS BETWEEN 6000-9000 FT. THE BAND OF STRATUS ALSO SEPARATES MOIST AIR FROM VERY DRY AIR AT 850MB. FOR EXAMPLE...FROM 00Z SOUNDINGS...THE 850MB DEWPOINT AT DVN WAS -20C WHILE IT WAS -2C AT MPX AND 1C AT OAX. THE BROAD SOUTHWEST FLOW ALOFT HAS RESULTED IN A WARM ADVECTION PATTERN ACROSS THE UPPER MIDWEST. 850MB TEMPS WERE +6C AT MPX AND OAX AT 00Z. THE LOW LEVEL SOUTHERLY FLOW WAS FAIRLY STRONG WITH 925MB PROFILER AND VWP DATA SHOWING SPEEDS OF 35-45KT AROUND THE FORECAST AREA. THESE WINDS ARE HOLDING TEMPERATURES UP FROM THE MID 30S TO MID 40S...WARMEST IN SOUTHEAST MINNESOTA. TODAY AND TONIGHT...FOCUS IS ON THAT SHORTWAVE ALONG THE UTAH/COLORADO BORDER. GOOD MODEL AGREEMENT REMAINS ON THIS SHORTWAVE LIFTING UP THROUGH THE SOUTHWEST FLOW AND MOVING INTO WESTERN PORTIONS OF THE FORECAST AREA BY 12Z MONDAY. BRIEF RIDGING DEVELOPS OVER THE FORECAST AREA TODAY DOWNSTREAM OF THIS SHORTWAVE...WHICH SHOULD ACT TO CLEAR THE CLOUDS UP SOMEWHAT. WITH THE RELATIVELY SPEAKING WARM START...SUNSHINE AND 925MB TEMPS AROUND 6C WHICH ARE SIMILAR TO YESTERDAY...ANTICIPATING HIGHS TO BE FAIRLY SIMILAR TO A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...THE 850MB MOISTURE STREAM CURRENTLY OVER WESTERN MINNESOTA AND IOWA WILL GET PUSHED EAST INTO THE FORECAST AREA BY THE SHORTWAVE. THE MAIN QUESTION IS IF DPVA AND ISENTROPIC LIFT AHEAD OF THIS SHORTWAVE WILL BE STRONG ENOUGH TO ACT ON THIS MOISTURE AND PRODUCE PRECIPITATION. MID CLOUD DEVELOPMENT IS A CERTAINTY...GIVEN WHAT HAPPENED LAST EVENING ON THE LEADING EDGE OF THE 850MB MOISTURE STREAM. THE 18.00Z NAM/REGIONAL CANADIAN PAINT A DRY PICTURE AND EVEN THE GFS WHICH LOOKS TO HAVE A BIT TOO MUCH MOISTURE COMPARED TO ALL OTHER MODELS PRODUCES LITTLE IF ANY PRECIPITATION BEFORE 12Z. THE 17.12Z ECMWF MEANWHILE REMAINS MOST ROBUST WITH 0.1-0.2 OF AN INCH OVER NORTHEAST IOWA BETWEEN 06-12Z MONDAY. NEW 18.00Z ECMWF IS SLIGHTLY DRIER. SREF TRENDS HAVE SHOWN LESS MEMBERS PRODUCING 0.01 OF AN INCH OVER THE LAST 5 RUNS...DOWN FROM 40-50 PERCENT TO 10-30 PERCENT. AT THIS POINT...CANNOT SEE GOING WITH THE MORE ROBUST ECMWF SOLUTION AND HAVE KEPT CHANCES LOW IN THE 20-30 PERCENT RANGE...CENTERED IN THE 09-12Z PERIOD. WITH THE INCREASING CLOUDS AND A SOUTHERLY BREEZE BEING MAINTAINED...A SLIGHTLY WARMER NIGHT THAN TONIGHT IS ANTICIPATED. MONDAY AND MONDAY NIGHT...THE SHORTWAVE OVER WESTERN PORTIONS OF THE FORECAST AREA AT 12Z LOOKS TO MOVE THROUGH THE REST OF THE FORECAST AREA BY EARLY AFTERNOON...WHILE THE TAIL END OF THE DEEP TROUGHING IN THE PACIFIC NORTHWEST IS PROGGED TO DROP DOWN INTO THE FORECAST AREA AFTER MIDNIGHT MONDAY NIGHT. THIS LATTER SHORTWAVE WILL COME THROUGH DRY SINCE THE SHORTWAVE COMING THROUGH MONDAY MORNING ENDS UP SCOURING OUT A LOT OF THE MOISTURE. THUS ALL FOCUS IS ON THE MONDAY MORNING PERIOD. AGAIN HERE...MODELS ARE AT ODDS WITH FORCING AND MOISTURE AVAILABILITY. THE 18.00Z NAM/REGIONAL CANADIAN SAYS THERE IS TOO MUCH DRY AIR BELOW 800MB AND THE FORCING IS TOO WEAK ABOVE IT TO ALLOW FOR PRECIPITATION TO MAKE IT TO THE SURFACE. ON THE OTHER HAND...THE 18.00Z GFS AND 17.12Z/18.00Z ECMWF ARE MORE ROBUST IN BOTH ARENAS AND END UP PRODUCING LIGHT QPF ACROSS MUCH OF THE AREA. SREF TRENDS FOR THE FULL DAY MONDAY ARE ALSO SIMILAR TO 06-12Z MONDAY...SHOWING A DECLINE OF MEMBERS PRODUCING AT LEAST 0.01 OF AN INCH. IT USED TO BE UP AT 70-80 PERCENT BUT NOW IS DOWN TO 30-60 PERCENT. THUS...CONFIDENCE REMAINS TOO LOW TO ADJUST THE PREVIOUS FORECAST PRECIPITATION CHANCES OF 20-40 PERCENT. CERTAINLY IF ANY PRECIPITATION OCCURS...ANY RAIN LOOKS REALLY LIGHT. REGARDING CLOUD COVER...IT NOW APPEARS THAT THE SHORTWAVE ON MONDAY MORNING SHOULD HELP TO CLEAR THE CLOUDS OUT AS IT MOVES AWAY DURING THE AFTERNOON. THERE MAY BE AN INCREASE OF CIRRUS WITH THE SHORTWAVE COMING IN MONDAY NIGHT...BUT THATS ABOUT IT. NOTE THAT THERE IS CONCERN FOR A LOW CLOUD DECK BASED ON THE GFS/ECMWF 925MB RH PROGS...BUT THEY MAY BE TOO MOIST. FOR NOW TAKING A COMPROMISE APPROACH BY SPEEDING UP THE CLEARING SOME FROM THE PREVIOUS FORECAST. HAVING MORE CLOUDS MONDAY WILL HOLD THE TEMPERATURES DOWN A FEW DEGREES FROM HIGHS OVER THE WEEKEND. A COOLER NIGHT SEEMS LIKELY TOO FOR MONDAY NIGHT...ESPECIALLY IF THE CLEARING OCCURS. TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THAT SHORTWAVE DROPPING INTO THE FORECAST AREA TUESDAY MORNING...SOME FAIRLY STRONG RIDGING IS PROGGED TO BUILD INTO THE FORECAST AREA BY TUESDAY EVENING. ABOUT ALL THAT SHORTWAVE IS GOING TO DO IS PREVENT THE 850MB TEMP CLIMB...NOTED BY 850MB TEMPS AT 18Z TUESDAY OF 5-7C. ONCE THE RIDGING STARTS BUILDING IN...THESE TEMPS CLIMB...TOPPING OUT AT 8C EAST TO 11C WEST BY 12Z WEDNESDAY. WITH WHAT SHOULD BE PLENTY OF SUN...HIGHS SHOULD BE ABLE TO TOP OUT IN THE 50S AGAIN ON TUESDAY GIVEN THE AFOREMENTIONED 850MB TEMPS. INCREASING SOUTHERLY FLOW TUESDAY NIGHT IN THE WAKE OF HIGH PRESSURE THAT CROSSES THE AREA ON TUESDAY WILL HELP TO KEEP TEMPERATURES UP IN SOUTHEAST MINNESOTA. FOLLOWED A BLEND OF GUIDANCE FOR LOWS. .LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FOCUS CONTINUES TO BE ON A POTENT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST WEDNESDAY MORNING. MODEL AGREEMENT HANDLING THIS POTENT TROUGH BEGINS TO DECLINE AS EARLY AS 12Z THURSDAY...WITH THE 18.00Z ECMWF/CANADIAN SHOWING A DIGGING NATURE TO IT INTO THE NORTHERN PLAINS. MEANWHILE...THE 18.00Z GFS TAKES A MORE PROGRESSIVE APPROACH AND SENDS IT UP INTO NORTHERN ONTARIO ON THURSDAY. BOTH THE GFS AND ECMWF HAVE COMPLETELY FLIPPED FROM PREVIOUS RUNS WITH THE HANDLING OF THIS POTENT TROUGH. THE 18.00Z ECMWF LOOKS MORE LIKE THE 17.00Z GFS WHILE THE 18.00Z GFS LOOKS MORE LIKE THE 16.12Z ECMWF. THIS HAS SIGNIFICANT IMPLICATIONS ON THE TEMPERATURE AND WIND FORECASTS...PRIMARILY FRIDAY AND BEYOND. WITH THE MORE DIGGING NATURE OF THE ECMWF/CANADIAN...THEY END UP CARVING OUT A DEEP TROUGH ACROSS THE WESTERN GREAT LAKES REGION FOR FRIDAY...THOUGH WITHIN THIS GROUP THE CANADIAN IS MORE PROGRESSIVE. WHICHEVER MODEL SCENARIO PLAYS OUT...IT APPEARS DRY WEATHER WOULD BE THE RULE WITH THE BEST JUXTAPOSITION OF FORCING AND MOISTURE EITHER NORTH OR SOUTHEAST OF THE AREA. GIVEN THE DIFFERENCES EARLY IN THE LONG TERM PERIOD...HARD TO SAY HOW THE WEEKEND WILL PLAY ITSELF OUT. NOTE THAT THE 18.00Z GFS ENSEMBLES HAVE A PRETTY GOOD SPREAD TOO WITH REGARDS TO THE POTENT TROUGH. THUS FOR NOW HAVE STAYED WITH A CONSENSUS APPROACH WHEN IT COMES TO THE WEEKEND...YIELDING COOLER AND A CONTINUATION OF DRY CONDITIONS. REGARDING TEMPERATURES...WEDNESDAY AND THANKSGIVING DAY STILL LOOK WELL ABOVE NORMAL...ESPECIALLY WEDNESDAY AS 925MB TEMPS CLIMB TO 10-12C FOR 18Z. MIXING TO 925MB YIELDS HIGHS FROM THE UPPER 50S TO MIDDLE 60S...THUS HAVE BOOSTED HIGHS A FEW DEGREES. RECORD HIGHS FOR WEDNESDAY ARE 72 AT LA CROSSE AND 69 AT ROCHESTER...STILL 5-10 DEGREES ABOVE THE GOING FORECAST. NOTE THAT 850MB TEMP STANDARDIZED ANOMALIES HAVE NOW JUMPED TO NEAR 2...SUPPORTING THE INCREASING IN HIGH TEMPERATURES. SOME COOLING IN 925MB TEMPS TAKES PLACE ON THANKSGIVING DAY AS A COLD FRONT MOVES INTO THE REGION. STILL...MOST LOCATIONS SHOULD TOP OUT AT LEAST IN THE MID TO UPPER 50S...MAYBE EVEN 60 AT SOME SOUTH OF I-90. RECORD HIGH FOR THURSDAY IS 59 AT LA CROSSE AND 65 AT ROCHESTER...THUS LA CROSSE MAY BE DOABLE TO BREAK. TEMPERATURES SHOULD RETURN CLOSER TO NORMAL FOR FRIDAY INTO THE WEEKEND IN THE WAKE OF THE COLD FRONT. IF THE 18.00Z ECMWF IS CORRECT...WE COULD EVEN BE BELOW NORMAL FOR THE WEEKEND. && .AVIATION...THROUGH 18Z MONDAY 1121 AM CST SUN NOV 18 2012 WILL BE WATCHING A MID-LEVEL TROUGH OF LOW PRESSURE AND SURFACE COLD FRONT APPROACH THE AREA FROM THE PLAINS LATE TONIGHT...AND THEN ACROSS THE AREA ON MONDAY. THIS WILL SPREAD CLOUDS INTO THE UPPER MISSISSIPPI RIVER REGION TONIGHT AND THEN PRODUCE SCATTERED -SHRA ACROSS PORTIONS OF SOUTHEAST MN/NORTHEAST IA INTO SOUTHWEST WISCONSIN TOWARD MORNING. EXPECTING SCATTERED -SHRA TO REMAIN EAST OF KRST BUT DID INCLUDE A VCSH MENTION AT KLSE AFTER 11Z SINCE THIS IS WHERE BETTER SURGE OF MOISTURE TRANSPORT WILL EXIST. PLAN ON VFR CONDITIONS THROUGH THE PERIOD WITH CIGS EXPECTED TO REMAIN AOA 4500 FT AGL. && .ARX WATCHES/WARNINGS/ADVISORIES... 212 AM CST SUN NOV 18 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
559 AM CST SUN NOV 18 2012 .SHORT TERM...THROUGH TUESDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TONIGHT INTO MONDAY AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A DEEP TROUGH FROM JUST OFF THE COAST OF BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST...AND SOUTHWEST FLOW FROM THE DESERT SOUTHWEST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. WITHIN THIS SOUTHWEST FLOW...SHORTWAVES OF NOTE ARE ALONG THE UTAH/COLORADO BORDER AND IN NORTHWEST MINNESOTA. DPVA AHEAD OF THIS LATTER SHORTWAVE COMBINED WITH 295-300K ISENTROPIC LIFT PRODUCED SHOWERS ACROSS NORTHEAST MINNESOTA. THE 295K ISENTROPIC LIFT ALSO EXTENDED SOUTHWEST FROM NORTHEAST MINNESOTA INTO CENTRAL IOWA...AND ALONG THIS ZONE IS A BAND OF STRATUS WITH CEILINGS BETWEEN 6000-9000 FT. THE BAND OF STRATUS ALSO SEPARATES MOIST AIR FROM VERY DRY AIR AT 850MB. FOR EXAMPLE...FROM 00Z SOUNDINGS...THE 850MB DEWPOINT AT DVN WAS -20C WHILE IT WAS -2C AT MPX AND 1C AT OAX. THE BROAD SOUTHWEST FLOW ALOFT HAS RESULTED IN A WARM ADVECTION PATTERN ACROSS THE UPPER MIDWEST. 850MB TEMPS WERE +6C AT MPX AND OAX AT 00Z. THE LOW LEVEL SOUTHERLY FLOW WAS FAIRLY STRONG WITH 925MB PROFILER AND VWP DATA SHOWING SPEEDS OF 35-45KT AROUND THE FORECAST AREA. THESE WINDS ARE HOLDING TEMPERATURES UP FROM THE MID 30S TO MID 40S...WARMEST IN SOUTHEAST MINNESOTA. TODAY AND TONIGHT...FOCUS IS ON THAT SHORTWAVE ALONG THE UTAH/COLORADO BORDER. GOOD MODEL AGREEMENT REMAINS ON THIS SHORTWAVE LIFTING UP THROUGH THE SOUTHWEST FLOW AND MOVING INTO WESTERN PORTIONS OF THE FORECAST AREA BY 12Z MONDAY. BRIEF RIDGING DEVELOPS OVER THE FORECAST AREA TODAY DOWNSTREAM OF THIS SHORTWAVE...WHICH SHOULD ACT TO CLEAR THE CLOUDS UP SOMEWHAT. WITH THE RELATIVELY SPEAKING WARM START...SUNSHINE AND 925MB TEMPS AROUND 6C WHICH ARE SIMILAR TO YESTERDAY...ANTICIPATING HIGHS TO BE FAIRLY SIMILAR TO A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...THE 850MB MOISTURE STREAM CURRENTLY OVER WESTERN MINNESOTA AND IOWA WILL GET PUSHED EAST INTO THE FORECAST AREA BY THE SHORTWAVE. THE MAIN QUESTION IS IF DPVA AND ISENTROPIC LIFT AHEAD OF THIS SHORTWAVE WILL BE STRONG ENOUGH TO ACT ON THIS MOISTURE AND PRODUCE PRECIPITATION. MID CLOUD DEVELOPMENT IS A CERTAINTY...GIVEN WHAT HAPPENED LAST EVENING ON THE LEADING EDGE OF THE 850MB MOISTURE STREAM. THE 18.00Z NAM/REGIONAL CANADIAN PAINT A DRY PICTURE AND EVEN THE GFS WHICH LOOKS TO HAVE A BIT TOO MUCH MOISTURE COMPARED TO ALL OTHER MODELS PRODUCES LITTLE IF ANY PRECIPITATION BEFORE 12Z. THE 17.12Z ECMWF MEANWHILE REMAINS MOST ROBUST WITH 0.1-0.2 OF AN INCH OVER NORTHEAST IOWA BETWEEN 06-12Z MONDAY. NEW 18.00Z ECMWF IS SLIGHTLY DRIER. SREF TRENDS HAVE SHOWN LESS MEMBERS PRODUCING 0.01 OF AN INCH OVER THE LAST 5 RUNS...DOWN FROM 40-50 PERCENT TO 10-30 PERCENT. AT THIS POINT...CANNOT SEE GOING WITH THE MORE ROBUST ECMWF SOLUTION AND HAVE KEPT CHANCES LOW IN THE 20-30 PERCENT RANGE...CENTERED IN THE 09-12Z PERIOD. WITH THE INCREASING CLOUDS AND A SOUTHERLY BREEZE BEING MAINTAINED...A SLIGHTLY WARMER NIGHT THAN TONIGHT IS ANTICIPATED. MONDAY AND MONDAY NIGHT...THE SHORTWAVE OVER WESTERN PORTIONS OF THE FORECAST AREA AT 12Z LOOKS TO MOVE THROUGH THE REST OF THE FORECAST AREA BY EARLY AFTERNOON...WHILE THE TAIL END OF THE DEEP TROUGHING IN THE PACIFIC NORTHWEST IS PROGGED TO DROP DOWN INTO THE FORECAST AREA AFTER MIDNIGHT MONDAY NIGHT. THIS LATTER SHORTWAVE WILL COME THROUGH DRY SINCE THE SHORTWAVE COMING THROUGH MONDAY MORNING ENDS UP SCOURING OUT A LOT OF THE MOISTURE. THUS ALL FOCUS IS ON THE MONDAY MORNING PERIOD. AGAIN HERE...MODELS ARE AT ODDS WITH FORCING AND MOISTURE AVAILABILITY. THE 18.00Z NAM/REGIONAL CANADIAN SAYS THERE IS TOO MUCH DRY AIR BELOW 800MB AND THE FORCING IS TOO WEAK ABOVE IT TO ALLOW FOR PRECIPITATION TO MAKE IT TO THE SURFACE. ON THE OTHER HAND...THE 18.00Z GFS AND 17.12Z/18.00Z ECMWF ARE MORE ROBUST IN BOTH ARENAS AND END UP PRODUCING LIGHT QPF ACROSS MUCH OF THE AREA. SREF TRENDS FOR THE FULL DAY MONDAY ARE ALSO SIMILAR TO 06-12Z MONDAY...SHOWING A DECLINE OF MEMBERS PRODUCING AT LEAST 0.01 OF AN INCH. IT USED TO BE UP AT 70-80 PERCENT BUT NOW IS DOWN TO 30-60 PERCENT. THUS...CONFIDENCE REMAINS TOO LOW TO ADJUST THE PREVIOUS FORECAST PRECIPITATION CHANCES OF 20-40 PERCENT. CERTAINLY IF ANY PRECIPITATION OCCURS...ANY RAIN LOOKS REALLY LIGHT. REGARDING CLOUD COVER...IT NOW APPEARS THAT THE SHORTWAVE ON MONDAY MORNING SHOULD HELP TO CLEAR THE CLOUDS OUT AS IT MOVES AWAY DURING THE AFTERNOON. THERE MAY BE AN INCREASE OF CIRRUS WITH THE SHORTWAVE COMING IN MONDAY NIGHT...BUT THATS ABOUT IT. NOTE THAT THERE IS CONCERN FOR A LOW CLOUD DECK BASED ON THE GFS/ECMWF 925MB RH PROGS...BUT THEY MAY BE TOO MOIST. FOR NOW TAKING A COMPROMISE APPROACH BY SPEEDING UP THE CLEARING SOME FROM THE PREVIOUS FORECAST. HAVING MORE CLOUDS MONDAY WILL HOLD THE TEMPERATURES DOWN A FEW DEGREES FROM HIGHS OVER THE WEEKEND. A COOLER NIGHT SEEMS LIKELY TOO FOR MONDAY NIGHT...ESPECIALLY IF THE CLEARING OCCURS. TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THAT SHORTWAVE DROPPING INTO THE FORECAST AREA TUESDAY MORNING...SOME FAIRLY STRONG RIDGING IS PROGGED TO BUILD INTO THE FORECAST AREA BY TUESDAY EVENING. ABOUT ALL THAT SHORTWAVE IS GOING TO DO IS PREVENT THE 850MB TEMP CLIMB...NOTED BY 850MB TEMPS AT 18Z TUESDAY OF 5-7C. ONCE THE RIDGING STARTS BUILDING IN...THESE TEMPS CLIMB...TOPPING OUT AT 8C EAST TO 11C WEST BY 12Z WEDNESDAY. WITH WHAT SHOULD BE PLENTY OF SUN...HIGHS SHOULD BE ABLE TO TOP OUT IN THE 50S AGAIN ON TUESDAY GIVEN THE AFOREMENTIONED 850MB TEMPS. INCREASING SOUTHERLY FLOW TUESDAY NIGHT IN THE WAKE OF HIGH PRESSURE THAT CROSSES THE AREA ON TUESDAY WILL HELP TO KEEP TEMPERATURES UP IN SOUTHEAST MINNESOTA. FOLLOWED A BLEND OF GUIDANCE FOR LOWS. .LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FOCUS CONTINUES TO BE ON A POTENT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST WEDNESDAY MORNING. MODEL AGREEMENT HANDLING THIS POTENT TROUGH BEGINS TO DECLINE AS EARLY AS 12Z THURSDAY...WITH THE 18.00Z ECMWF/CANADIAN SHOWING A DIGGING NATURE TO IT INTO THE NORTHERN PLAINS. MEANWHILE...THE 18.00Z GFS TAKES A MORE PROGRESSIVE APPROACH AND SENDS IT UP INTO NORTHERN ONTARIO ON THURSDAY. BOTH THE GFS AND ECMWF HAVE COMPLETELY FLIPPED FROM PREVIOUS RUNS WITH THE HANDLING OF THIS POTENT TROUGH. THE 18.00Z ECMWF LOOKS MORE LIKE THE 17.00Z GFS WHILE THE 18.00Z GFS LOOKS MORE LIKE THE 16.12Z ECMWF. THIS HAS SIGNIFICANT IMPLICATIONS ON THE TEMPERATURE AND WIND FORECASTS...PRIMARILY FRIDAY AND BEYOND. WITH THE MORE DIGGING NATURE OF THE ECMWF/CANADIAN...THEY END UP CARVING OUT A DEEP TROUGH ACROSS THE WESTERN GREAT LAKES REGION FOR FRIDAY...THOUGH WITHIN THIS GROUP THE CANADIAN IS MORE PROGRESSIVE. WHICHEVER MODEL SCENARIO PLAYS OUT...IT APPEARS DRY WEATHER WOULD BE THE RULE WITH THE BEST JUXTAPOSITION OF FORCING AND MOISTURE EITHER NORTH OR SOUTHEAST OF THE AREA. GIVEN THE DIFFERENCES EARLY IN THE LONG TERM PERIOD...HARD TO SAY HOW THE WEEKEND WILL PLAY ITSELF OUT. NOTE THAT THE 18.00Z GFS ENSEMBLES HAVE A PRETTY GOOD SPREAD TOO WITH REGARDS TO THE POTENT TROUGH. THUS FOR NOW HAVE STAYED WITH A CONSENSUS APPROACH WHEN IT COMES TO THE WEEKEND...YIELDING COOLER AND A CONTINUATION OF DRY CONDITIONS. REGARDING TEMPERATURES...WEDNESDAY AND THANKSGIVING DAY STILL LOOK WELL ABOVE NORMAL...ESPECIALLY WEDNESDAY AS 925MB TEMPS CLIMB TO 10-12C FOR 18Z. MIXING TO 925MB YIELDS HIGHS FROM THE UPPER 50S TO MIDDLE 60S...THUS HAVE BOOSTED HIGHS A FEW DEGREES. RECORD HIGHS FOR WEDNESDAY ARE 72 AT LA CROSSE AND 69 AT ROCHESTER...STILL 5-10 DEGREES ABOVE THE GOING FORECAST. NOTE THAT 850MB TEMP STANDARDIZED ANOMALIES HAVE NOW JUMPED TO NEAR 2...SUPPORTING THE INCREASING IN HIGH TEMPERATURES. SOME COOLING IN 925MB TEMPS TAKES PLACE ON THANKSGIVING DAY AS A COLD FRONT MOVES INTO THE REGION. STILL...MOST LOCATIONS SHOULD TOP OUT AT LEAST IN THE MID TO UPPER 50S...MAYBE EVEN 60 AT SOME SOUTH OF I-90. RECORD HIGH FOR THURSDAY IS 59 AT LA CROSSE AND 65 AT ROCHESTER...THUS LA CROSSE MAY BE DOABLE TO BREAK. TEMPERATURES SHOULD RETURN CLOSER TO NORMAL FOR FRIDAY INTO THE WEEKEND IN THE WAKE OF THE COLD FRONT. IF THE 18.00Z ECMWF IS CORRECT...WE COULD EVEN BE BELOW NORMAL FOR THE WEEKEND. && .AVIATION...TODAY AND TONIGHT 557 AM CST SUN NOV 18 2012 A SCATTERED TO BROKEN DECK OF ALTOCUMULUS CLOUDS WILL GRADUALLY DISSIPATE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON. A COLD FRONT WILL BRING ANOTHER ROUND OF MID AND HIGH CLOUDS TO THE AREA TONIGHT. THERE WILL ALSO BE SOME ISOLATED TO SCATTERED SHOWERS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA AFTER 19.06Z TONIGHT. SINCE THEIR COVERAGE IS VERY SMALL...DID NOT INCLUDE THEM AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 212 AM CST SUN NOV 18 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
212 AM CST SUN NOV 18 2012 .SHORT TERM...THROUGH TUESDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES TONIGHT INTO MONDAY AS WELL AS TEMPERATURES THROUGHOUT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A DEEP TROUGH FROM JUST OFF THE COAST OF BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST...AND SOUTHWEST FLOW FROM THE DESERT SOUTHWEST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. WITHIN THIS SOUTHWEST FLOW...SHORTWAVES OF NOTE ARE ALONG THE UTAH/COLORADO BORDER AND IN NORTHWEST MINNESOTA. DPVA AHEAD OF THIS LATTER SHORTWAVE COMBINED WITH 295-300K ISENTROPIC LIFT PRODUCED SHOWERS ACROSS NORTHEAST MINNESOTA. THE 295K ISENTROPIC LIFT ALSO EXTENDED SOUTHWEST FROM NORTHEAST MINNESOTA INTO CENTRAL IOWA...AND ALONG THIS ZONE IS A BAND OF STRATUS WITH CEILINGS BETWEEN 6000-9000 FT. THE BAND OF STRATUS ALSO SEPARATES MOIST AIR FROM VERY DRY AIR AT 850MB. FOR EXAMPLE...FROM 00Z SOUNDINGS...THE 850MB DEWPOINT AT DVN WAS -20C WHILE IT WAS -2C AT MPX AND 1C AT OAX. THE BROAD SOUTHWEST FLOW ALOFT HAS RESULTED IN A WARM ADVECTION PATTERN ACROSS THE UPPER MIDWEST. 850MB TEMPS WERE +6C AT MPX AND OAX AT 00Z. THE LOW LEVEL SOUTHERLY FLOW WAS FAIRLY STRONG WITH 925MB PROFILER AND VWP DATA SHOWING SPEEDS OF 35-45KT AROUND THE FORECAST AREA. THESE WINDS ARE HOLDING TEMPERATURES UP FROM THE MID 30S TO MID 40S...WARMEST IN SOUTHEAST MINNESOTA. TODAY AND TONIGHT...FOCUS IS ON THAT SHORTWAVE ALONG THE UTAH/COLORADO BORDER. GOOD MODEL AGREEMENT REMAINS ON THIS SHORTWAVE LIFTING UP THROUGH THE SOUTHWEST FLOW AND MOVING INTO WESTERN PORTIONS OF THE FORECAST AREA BY 12Z MONDAY. BRIEF RIDGING DEVELOPS OVER THE FORECAST AREA TODAY DOWNSTREAM OF THIS SHORTWAVE...WHICH SHOULD ACT TO CLEAR THE CLOUDS UP SOMEWHAT. WITH THE RELATIVELY SPEAKING WARM START...SUNSHINE AND 925MB TEMPS AROUND 6C WHICH ARE SIMILAR TO YESTERDAY...ANTICIPATING HIGHS TO BE FAIRLY SIMILAR TO A FEW DEGREES WARMER THAN YESTERDAY. FOR TONIGHT...THE 850MB MOISTURE STREAM CURRENTLY OVER WESTERN MINNESOTA AND IOWA WILL GET PUSHED EAST INTO THE FORECAST AREA BY THE SHORTWAVE. THE MAIN QUESTION IS IF DPVA AND ISENTROPIC LIFT AHEAD OF THIS SHORTWAVE WILL BE STRONG ENOUGH TO ACT ON THIS MOISTURE AND PRODUCE PRECIPITATION. MID CLOUD DEVELOPMENT IS A CERTAINTY...GIVEN WHAT HAPPENED LAST EVENING ON THE LEADING EDGE OF THE 850MB MOISTURE STREAM. THE 18.00Z NAM/REGIONAL CANADIAN PAINT A DRY PICTURE AND EVEN THE GFS WHICH LOOKS TO HAVE A BIT TOO MUCH MOISTURE COMPARED TO ALL OTHER MODELS PRODUCES LITTLE IF ANY PRECIPITATION BEFORE 12Z. THE 17.12Z ECMWF MEANWHILE REMAINS MOST ROBUST WITH 0.1-0.2 OF AN INCH OVER NORTHEAST IOWA BETWEEN 06-12Z MONDAY. NEW 18.00Z ECMWF IS SLIGHTLY DRIER. SREF TRENDS HAVE SHOWN LESS MEMBERS PRODUCING 0.01 OF AN INCH OVER THE LAST 5 RUNS...DOWN FROM 40-50 PERCENT TO 10-30 PERCENT. AT THIS POINT...CANNOT SEE GOING WITH THE MORE ROBUST ECMWF SOLUTION AND HAVE KEPT CHANCES LOW IN THE 20-30 PERCENT RANGE...CENTERED IN THE 09-12Z PERIOD. WITH THE INCREASING CLOUDS AND A SOUTHERLY BREEZE BEING MAINTAINED...A SLIGHTLY WARMER NIGHT THAN TONIGHT IS ANTICIPATED. MONDAY AND MONDAY NIGHT...THE SHORTWAVE OVER WESTERN PORTIONS OF THE FORECAST AREA AT 12Z LOOKS TO MOVE THROUGH THE REST OF THE FORECAST AREA BY EARLY AFTERNOON...WHILE THE TAIL END OF THE DEEP TROUGHING IN THE PACIFIC NORTHWEST IS PROGGED TO DROP DOWN INTO THE FORECAST AREA AFTER MIDNIGHT MONDAY NIGHT. THIS LATTER SHORTWAVE WILL COME THROUGH DRY SINCE THE SHORTWAVE COMING THROUGH MONDAY MORNING ENDS UP SCOURING OUT A LOT OF THE MOISTURE. THUS ALL FOCUS IS ON THE MONDAY MORNING PERIOD. AGAIN HERE...MODELS ARE AT ODDS WITH FORCING AND MOISTURE AVAILABILITY. THE 18.00Z NAM/REGIONAL CANADIAN SAYS THERE IS TOO MUCH DRY AIR BELOW 800MB AND THE FORCING IS TOO WEAK ABOVE IT TO ALLOW FOR PRECIPITATION TO MAKE IT TO THE SURFACE. ON THE OTHER HAND...THE 18.00Z GFS AND 17.12Z/18.00Z ECMWF ARE MORE ROBUST IN BOTH ARENAS AND END UP PRODUCING LIGHT QPF ACROSS MUCH OF THE AREA. SREF TRENDS FOR THE FULL DAY MONDAY ARE ALSO SIMILAR TO 06-12Z MONDAY...SHOWING A DECLINE OF MEMBERS PRODUCING AT LEAST 0.01 OF AN INCH. IT USED TO BE UP AT 70-80 PERCENT BUT NOW IS DOWN TO 30-60 PERCENT. THUS...CONFIDENCE REMAINS TOO LOW TO ADJUST THE PREVIOUS FORECAST PRECIPITATION CHANCES OF 20-40 PERCENT. CERTAINLY IF ANY PRECIPITATION OCCURS...ANY RAIN LOOKS REALLY LIGHT. REGARDING CLOUD COVER...IT NOW APPEARS THAT THE SHORTWAVE ON MONDAY MORNING SHOULD HELP TO CLEAR THE CLOUDS OUT AS IT MOVES AWAY DURING THE AFTERNOON. THERE MAY BE AN INCREASE OF CIRRUS WITH THE SHORTWAVE COMING IN MONDAY NIGHT...BUT THATS ABOUT IT. NOTE THAT THERE IS CONCERN FOR A LOW CLOUD DECK BASED ON THE GFS/ECMWF 925MB RH PROGS...BUT THEY MAY BE TOO MOIST. FOR NOW TAKING A COMPROMISE APPROACH BY SPEEDING UP THE CLEARING SOME FROM THE PREVIOUS FORECAST. HAVING MORE CLOUDS MONDAY WILL HOLD THE TEMPERATURES DOWN A FEW DEGREES FROM HIGHS OVER THE WEEKEND. A COOLER NIGHT SEEMS LIKELY TOO FOR MONDAY NIGHT...ESPECIALLY IF THE CLEARING OCCURS. TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THAT SHORTWAVE DROPPING INTO THE FORECAST AREA TUESDAY MORNING...SOME FAIRLY STRONG RIDGING IS PROGGED TO BUILD INTO THE FORECAST AREA BY TUESDAY EVENING. ABOUT ALL THAT SHORTWAVE IS GOING TO DO IS PREVENT THE 850MB TEMP CLIMB...NOTED BY 850MB TEMPS AT 18Z TUESDAY OF 5-7C. ONCE THE RIDGING STARTS BUILDING IN...THESE TEMPS CLIMB...TOPPING OUT AT 8C EAST TO 11C WEST BY 12Z WEDNESDAY. WITH WHAT SHOULD BE PLENTY OF SUN...HIGHS SHOULD BE ABLE TO TOP OUT IN THE 50S AGAIN ON TUESDAY GIVEN THE AFOREMENTIONED 850MB TEMPS. INCREASING SOUTHERLY FLOW TUESDAY NIGHT IN THE WAKE OF HIGH PRESSURE THAT CROSSES THE AREA ON TUESDAY WILL HELP TO KEEP TEMPERATURES UP IN SOUTHEAST MINNESOTA. FOLLOWED A BLEND OF GUIDANCE FOR LOWS. .LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT 212 AM CST SUN NOV 18 2012 MAIN FOCUS CONTINUES TO BE ON A POTENT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST WEDNESDAY MORNING. MODEL AGREEMENT HANDLING THIS POTENT TROUGH BEGINS TO DECLINE AS EARLY AS 12Z THURSDAY...WITH THE 18.00Z ECMWF/CANADIAN SHOWING A DIGGING NATURE TO IT INTO THE NORTHERN PLAINS. MEANWHILE...THE 18.00Z GFS TAKES A MORE PROGRESSIVE APPROACH AND SENDS IT UP INTO NORTHERN ONTARIO ON THURSDAY. BOTH THE GFS AND ECMWF HAVE COMPLETELY FLIPPED FROM PREVIOUS RUNS WITH THE HANDLING OF THIS POTENT TROUGH. THE 18.00Z ECMWF LOOKS MORE LIKE THE 17.00Z GFS WHILE THE 18.00Z GFS LOOKS MORE LIKE THE 16.12Z ECMWF. THIS HAS SIGNIFICANT IMPLICATIONS ON THE TEMPERATURE AND WIND FORECASTS...PRIMARILY FRIDAY AND BEYOND. WITH THE MORE DIGGING NATURE OF THE ECMWF/CANADIAN...THEY END UP CARVING OUT A DEEP TROUGH ACROSS THE WESTERN GREAT LAKES REGION FOR FRIDAY...THOUGH WITHIN THIS GROUP THE CANADIAN IS MORE PROGRESSIVE. WHICHEVER MODEL SCENARIO PLAYS OUT...IT APPEARS DRY WEATHER WOULD BE THE RULE WITH THE BEST JUXTAPOSITION OF FORCING AND MOISTURE EITHER NORTH OR SOUTHEAST OF THE AREA. GIVEN THE DIFFERENCES EARLY IN THE LONG TERM PERIOD...HARD TO SAY HOW THE WEEKEND WILL PLAY ITSELF OUT. NOTE THAT THE 18.00Z GFS ENSEMBLES HAVE A PRETTY GOOD SPREAD TOO WITH REGARDS TO THE POTENT TROUGH. THUS FOR NOW HAVE STAYED WITH A CONSENSUS APPROACH WHEN IT COMES TO THE WEEKEND...YIELDING COOLER AND A CONTINUATION OF DRY CONDITIONS. REGARDING TEMPERATURES...WEDNESDAY AND THANKSGIVING DAY STILL LOOK WELL ABOVE NORMAL...ESPECIALLY WEDNESDAY AS 925MB TEMPS CLIMB TO 10-12C FOR 18Z. MIXING TO 925MB YIELDS HIGHS FROM THE UPPER 50S TO MIDDLE 60S...THUS HAVE BOOSTED HIGHS A FEW DEGREES. RECORD HIGHS FOR WEDNESDAY ARE 72 AT LA CROSSE AND 69 AT ROCHESTER...STILL 5-10 DEGREES ABOVE THE GOING FORECAST. NOTE THAT 850MB TEMP STANDARDIZED ANOMALIES HAVE NOW JUMPED TO NEAR 2...SUPPORTING THE INCREASING IN HIGH TEMPERATURES. SOME COOLING IN 925MB TEMPS TAKES PLACE ON THANKSGIVING DAY AS A COLD FRONT MOVES INTO THE REGION. STILL...MOST LOCATIONS SHOULD TOP OUT AT LEAST IN THE MID TO UPPER 50S...MAYBE EVEN 60 AT SOME SOUTH OF I-90. RECORD HIGH FOR THURSDAY IS 59 AT LA CROSSE AND 65 AT ROCHESTER...THUS LA CROSSE MAY BE DOABLE TO BREAK. TEMPERATURES SHOULD RETURN CLOSER TO NORMAL FOR FRIDAY INTO THE WEEKEND IN THE WAKE OF THE COLD FRONT. IF THE 18.00Z ECMWF IS CORRECT...WE COULD EVEN BE BELOW NORMAL FOR THE WEEKEND. && .AVIATION... 1115 PM CST SAT NOV 17 2012 AN UPPER LEVEL DISTURBANCE WAS SPINNING ACROSS NORTHERN PARTS OF THE REGION TONIGHT...RESULTING IN SOME MID/HIGH LEVEL CLOUDINESS. CIGS WERE MOSTLY 6-10 10 KFT...AND EXPECT THEM TO CLEAR AROUND 15Z OR SO SUN WITH THE EXIT OF THE SHORTWAVE. MORE MID/HIGH LEVEL CIGS WILL RETURN SUNDAY NIGHT AS ANOTHER SHORTWAVE APPROACHES FROM THE SOUTHERN PLAINS. THIS SYSTEM COULD PRODUCE SOME LIGHT PCPN CHANCES...WITH THE BETTER CHANCES COMING AFTER 06Z MONDAY. WINDS WILL STAY UP TONIGHT AS THE TIGHT PRESSURE GRADIENT REMAINS...AND SUN AFTERNOON SHOULD BE FAIRLY SIMILAR TO SAT AFTERNOON. EXPECT MIXING TO RESULT IN AFTERNOON GUSTINESS...CLOSE TO 25 KTS AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 212 AM CST SUN NOV 18 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
358 AM EST TUE NOV 20 2012 .SYNOPSIS... THE REGION WILL REMAIN BETWEEN HIGH PRESSURE EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY AND LOW PRESSURE OVER THE WESTERN ATLANTIC THROUGH THURSDAY. A COLD FRONT WILL THEN APPROACH FROM THE NORTHWEST LATE FRIDAY INTO SATURDAY...WITH HIGH PRESSURE REBUILDING FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... HIGH PRESSURE WILL REMAIN ANCHORED OVER THE REGION TODAY AS A LARGE OCEANIC STORM MEANDERS WELL OF THE U.S. EAST COAST. A FAIRLY ZONAL FLOW WILL DOMINATE ALOFT AS SHORTWAVE ENERGY OVER THE NORTHERN MISSISSIPPI VALLEY BEGINS TO DIG SOUTH. THERE IS MUCH UNCERTAINTY ON HOW MUCH CLOUD COVER WILL OCCUR TODAY. CIRRUS BEING ENHANCED BY THE LEFT EXIT REGION OF A 115 KT JET STREAK WILL OVERSPREAD THE AREA FROM THE WEST LATER TODAY AS THE SUBTROPICAL JET AXIS DROPS FARTHER TO THE SOUTH AND EAST. MEANWHILE LOW CLOUDS SPREADING SOUTHWEST OUT OF NORTH CAROLINA ARE POISED TO MOVE INTO THE CHARLESTON TRI-COUNTY AREA BY SUNRISE. 975MB RUC MOISTURE PROGS SUGGEST MUCH OF THIS LOW-LEVEL CLOUD COVER WILL MIX OUT LATER THIS MORNING AS TEMPERATURES WARM WITH SKIES BECOMING PARTLY CLOUDY LATER TODAY ACROSS A GOOD PORTION OF THE AREA. HOWEVER...THERE REMAINS MUCH UNCERTAINTY ON EXACTLY HOW THE SKY COVER FORECAST WILL PLAY OUT WITH SOME GUIDANCE SUGGESTING SKIES WILL REMAIN MOSTLY CLOUDY FOR A GOOD PORTION OF THE DAY. LATER SHIFTS WILL MOST CERTAINLY HAVE TO MADE SOME ADJUSTMENTS AS THE DAY PROGRESSES. HIGHS WILL TOP OUT IN THE MID-UPPER 60S... WARMEST ACROSS THE SOUTH. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... TONIGHT...SIMILAR TO MONDAY EVENING...SKIES SHOULD CLEAR A BIT WITH THE LOSS OF INSOLATION. MORE RAPID CLEARING IS EXPECTED TO OCCUR AFTER MIDNIGHT AS THE CORE OF THE AFOREMENTIONED SHORTWAVE DIGS TO THE WEST AND SOUTH...THUS SHUNTING THE SUBTROPICAL JET FAR TO THE SOUTH. EXPECT MOSTLY CLEAR SKIES TO DOMINATE BETWEEN MIDNIGHT AND SUNRISE WEDNESDAY. THE BOUNDARY LAYER SHOULD DECOUPLE FAIRLY QUICKLY THIS EVENING. CALM/LIGHT WINDS COUPLED WITH CLEARING SKIES WILL YIELD IMPROVING RADIATIONAL CONDITIONS OVERNIGHT. LOWS WILL RANGE FROM THE LOWER 40S WELL INLAND TO THE UPPER 40S AT THE COAST. WEDNESDAY AND THURSDAY...AN AMPLIFIED UPPER TROUGH WILL CROSS THE EAST COAST STATES WEDNESDAY MORNING AND MOVE OFFSHORE LATER IN THE DAY. WHILE THE DEPARTING UPPER TROUGH STRENGTHENS THE ATLANTIC SURFACE LOW FAR OUT TO SEA...SURFACE HIGH PRESSURE AND UPPER RIDGING WILL BUILD IN FROM THE WEST. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL THEN DOMINATE THE PATTERN OVER THE LAND AREAS THROUGH THURSDAY. LACKING ANY DEEP MOISTURE AS THE UPPER TROUGH PASSES THE REGION WEDNESDAY...FOLLOWED BY LITTLE UPPER LEVEL SUPPORT IN ITS WAKE...EXPECT DRY WEATHER TO PREVAIL THROUGH AT LEAST THURSDAY. HIGH TEMPERATURES WILL TREND BACK UP TOWARD SEASONAL NORMALS...REACHING THE MID TO UPPER 60S EACH AFTERNOON. NIGHTTIME LOW TEMPERATURES WILL ACTUALLY FALL BELOW NORMAL...AS DECOUPLING WINDS AND CLEAR SKIES SUPPORT IDEAL RADIATIONAL COOLING. LOW TEMPERATURES WEDNESDAY NIGHT WILL RANGE FROM AROUND 40 DEGREES WELL INLAND TO THE MID 40S NEAR THE COAST...AND THEN FALL TO EVEN COOLER LEVELS THURSDAY NIGHT IN THE UPPER 30S TO AROUND 40S MOST LOCATIONS AWAY FROM THE IMMEDIATE COAST. FRIDAY...AN UPPER LOW WELL TO THE NORTH WILL MOVE ACROSS THE GREAT LAKES REGION AND INTO THE NEW ENGLAND STATES LATE IN THE WEEK. THE RIDGING ALOFT WILL BREAK DOWN AHEAD OF THE MAIN TROUGH AXIS...ALLOWING A COLD FRONT TO RAPIDLY APPROACH FROM THE NORTHWEST. WEST TO NORTHWEST FLOW REMAIN PROMINENT THROUGHOUT THE PROFILE AS THE FRONT NEARS THE REGION...SUGGESTING THE FEATURE WILL LACK A DECENT TAP INTO MOISTURE. THUS EXPECT DRY CONDITIONS TO CONTINUE INTO FRIDAY. HIGH TEMPERATURES FRIDAY AFTERNOON COULD BE THE WARMEST OF THE PERIOD...LIKELY DUE TO PRE-FRONTAL COMPRESSION AND WINDS BRIEFLY BACKING TO THE SOUTHWEST. && .LONG TERM /SATURDAY THROUGH MONDAY/... A COLD FRONT WILL DROP SOUTHEAST THROUGH THE FORECAST AREA LATE FRIDAY INTO EARLY SATURDAY...AS AN UPPER TROUGH CROSSES THE MID ATLANTIC COASTLINE BY SATURDAY AFTERNOON. ALTHOUGH THE FRONT IS NOT EXPECTED TO BRING PRECIPITATION TO THE AREA...STRONG COLD ADVECTION WILL FOLLOW IN ITS WAKE THROUGH THE WEEKEND. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE MID TO UPPER 60S...THEN TREND EVEN COOLER IN THE LOWER 60S FOR SUNDAY AFTERNOON. BROAD SURFACE HIGH PRESSURE WILL STEADILY SLIP FROM THE LOWER MISSISSIPPI VALLEY TOWARD THE SOUTHEAST STATES THROUGH SUNDAY WITHIN PROGRESSIVE ZONAL FLOW ALOFT. ANOTHER LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST MONDAY THROUGH TUESDAY...BUT TIMING AND IMPACTS ARE TOO UNCERTAIN THIS FAR OUT. WILL THUS MAINTAIN RAIN CHANCES LESS THAN 15 PERCENT THROUGH THE EXTENDED PERIOD. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... IT NOW APPEARS LOW CLOUDS STREAMING IN FROM NORTH CAROLINA AND THE PEE DEE WILL REACH KCHS ROUGHLY BETWEEN 10-11Z. THIS WILL RESULT IN PERIOD OF LOW-END MVFR CIGS THROUGH ABOUT 15Z. WHILE A BRIEF STINT TO HIGH-END IFR CAN NOT BE RULED OUT...THEY SHOULD REMAIN ABOVE THE TERMINAL/S ALTERNATE MINIMUMS. STILL EXPECT VFR CONDITIONS AT KSAV WITH THESE CLOUDS REMAINING TO THE NORTH. EXTENDED AVIATION OUTLOOK...THERE NO SIGNIFICANT ISSUES. && .MARINE... TODAY...THE MARINE AREA WILL SEE IMPROVING CONDITIONS THROUGH THE DAY. SEAS STILL LOOK TO REMAIN ABOVE 6 FT ACROSS THE CHARLESTON COUNTY COASTAL WATERS UNTIL LATE MORNING SO FLAGS WILL BE EXTENDED BY A FEW HOURS WITH SEAS 2-4 FT OVER THE REMAINING NEARSHORE LEGS. SEAS OF 6-8 FT ARE FORECAST TO REMAIN OVER THE GEORGIA OFFSHORE WATERS THROUGH THE AFTERNOON SO A SMALL CRAFT ADVISORY WILL REMAIN IN FORCE THERE. TONIGHT...SHOULD SEE A BIT OF AN INCREASE IN WINDS OVERNIGHT IN RESPONSE TO SHORTWAVE ENERGY APPROACHING FROM THE WEST. SPEEDS SHOULD BE NO HIGHER 15-20 KT OVER THE OFFSHORE WATERS WITH 10-15 KT CLOSER TO THE COAST. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS TO 5-7 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT OVERNIGHT FOR THE GEORGIA OFFSHORE LEG. WEDNESDAY THROUGH SATURDAY...WINDS AND SEAS WILL REMAIN ELEVATED THROUGH MID WEEK...AS THE PRESSURE GRADIENT REMAINS ENHANCED OVER THE WATERS BETWEEN BROAD HIGH PRESSURE INLAND AND A LOW PRESSURE SYSTEM FARTHER OUT IN THE ATLANTIC. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS FOR NEARSHORE WATERS. HOWEVER A COMBINATION OF NORTH/NORTHEAST WINDS...LONG PERIOD SWELLS AND COLD ADVECTION ASSOCIATED WITH BUILDING HIGH PRESSURE FROM THE WEST WILL ALLOW SMALL CRAFT ADVISORY CONDITIONS TO PERSIST OVER OUTER GEORGIA WATERS THROUGH MID WEEK AND POSSIBLY THROUGH LATE WEEK. CONDITIONS WILL THEN SLOWLY IMPROVE OVER ALL WATERS LATE WEEK...AS THE LOW PRESSURE SYSTEM SHIFTS FURTHER OFFSHORE AND THE PRESSURE GRADIENT WEAKENS ACCORDINGLY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR AMZ350. && $$ ST/79
AREA FORECAST DISCUSSION
NWS DES MOINES IA
339 AM CST TUE NOV 20 2012 .SHORT TERM /TODAY/... WEAK COLD FRONT IS PUSHING INTO SOUTHEAST IOWA. MOISTURE AHEAD OF THE FRONT...COMBINED WITH LIGHT WINDS AND CLEAR SKIES...HAS RESULTED IN WIDESPREAD DENSE FOG. ADVISORY REMAINS IN EFFECT FOR THE EASTERN PART OF THE CWA THROUGH 16Z. FOG WILL ERODE AWAY FROM THE WEST...BUT ONLY SLOW PROGRESS IS EXPECTED. HRRR IS QUITE AGGRESSIVE IN HOLDING ONTO THE FOG AND DO NOT EXPECTED IT TO LAST INTO THE AFTERNOON AS IT IS INDICATING. A COOLER START THIS MORNING THAN YESTERDAY WILL HELP KEEP TEMPS BELOW 60 ACROSS THE CWA TODAY. IN ADDITION...LIGHT WINDS WILL LIMIT MIXING DEPTH AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... RIDGE WILL BUILD IN BEHIND WEAK FRONTAL BOUNDARY FOR THE BEGINNING OF THE EXTENDED. UNDER RIDGE WITH SURFACE HIGH PRESSURE AND STRONG SOUTHERLY FLOW...TEMPERATURES WILL REMAIN WARM...WELL ABOVE NORMAL FOR NOVEMBER. HAVE KEPT TEMPERATURES NEAR GOING FORECAST...WITH WARMEST DAY WEDNESDAY AS WAA INCREASES AHEAD OF A FRONTAL BOUNDARY...AND CONDITIONS LOOK RIGHT FOR GOOD MIXING. COULD SEE TEMPERATURES POP A FEW DEGREES ABOVE GOING IN LOCATIONS FOR WEDNESDAY IF MIXING IS MAXIMIZED AS 85MB TEMPS WILL BE NEAR 14C ACROSS THE WEST. A WEAK FRONTAL BOUNDARY WILL PUSH ACROSS THE AREA FOR THURSDAY...WITH TEMPERATURES SLIGHTLY COOLER BEHIND THE BOUNDARY. HAVE LEFT SLIGHT CHANCE POPS ACROSS THE SOUTH FOR THURSDAY AS MOISTURE INCREASES. HOWEVER...DO NOT HAVE A LOT OF CONFIDENCE IN THESE CHANCE POPS AS MOISTURE IS SOMEWHAT LACKING. GFS IS MUCH MORE AGGRESSIVE WITH MOISTURE HEAD OF BOUNDARY...WITH NAM AND ECMWF MUCH LESS SO. HOWEVER...WITH FORCING ASSOCIATED WITH BOUNDARY COULD SEE SOME PRECIPITATION EVEN WITH LIMITED MOISTURE AND HAVE LEFT SLIGHT CHANCE POPS GOING. A MUCH STRONGER SYSTEM PUSHES THROUGH THURSDAY NIGHT...WITH A LARGE COOL DOWN IN STORE FOR THE END OF THE WEEK AS TEMPERATURES RETURN TO NEAR NORMAL. LOW PRESSURE SYSTEM WILL TRACK TO THE NORTH...AND COULD SEE SOME WRAP AROUND MOISTURE BRING LIGHT PRECIPITATION TO THE NORTH FRIDAY AND FRIDAY NIGHT...HOWEVER HAVE LEFT OUT ANY MENTION OF PRECIPITATION ATTM AS BEST FORCING WILL REMAIN NORTH INTO MINNESOTA. THE END OF THE PERIOD BECOMES A BIT TRICKY AS MODELS BUILD IN A WEAK RIDGE FOR THE WEEKEND...WITH TEMPERATURES AGAIN ABLE TO WARM NICELY. HOWEVER...THERE IS LITTLE AGREEMENT WITH SYSTEM FOR LATE IN THE WEEK. CURRENT MODEL TRENDS ARE TO HAVE A LOW PRESSURE SYSTEM PUSH ACROSS CANADA...BREAKING DOWN WEAK RIDGING. FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW PRESSURES SYSTEM WILL ALLOW FOR CHANCES FOR PRECIPITATION ACROSS THE CWA BY LATE MONDAY. HOWEVER...THERE IS NOT GOOD AGREEMENT IN THE TIMING AND LOCATION OF THIS SYSTEM AND DO NOT HAVE HIGH CONFIDENCE. THIS WILL NEED TO BE WATCHED CLOSELY. && .AVIATION...20/06Z HAVE UPDATED TAFS TO INCLUDE LOWER VISIBILITY ACROSS THE NORTH AND EAST OVERNIGHT. SOME QUESTION AS TO HOW LONG LOW VISIBILITY WILL LAST AND IF VARIABLE CONDITIONS WILL DEVELOP WITH THE VSBY AS TEMPS WARM AND FALL DUE TO FOG FORMATION. WEAK BOUNDARY EXPECTED TO ARRIVE OVER EAST BY 12Z AS EXPECTED...AND THIS WILL FOCUS THE FOG IN THIS LOCATION. OVER THE REMAINDER OF THE SITES NOT MUCH EXPECTED AT KDSM AND KFOD...BUT KALO...KOTM...AND KMCW LIFR TO IFR VSBY AND CIGS CAN BE EXPECTED AT TIMES UNTIL THE FOG LIFTS AFT 14-15Z. THE REMAINDER OF THE FORECAST WILL BECOME BENIGN WITH VFR CONDITIONS RETURNING. && .DMX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BLACK HAWK- BREMER-BUTLER-DAVIS-GRUNDY-JASPER-MAHASKA-MARSHALL-POWESHIEK- TAMA-WAPELLO. && $$ SHORT TERM...MS NOV 12 LONG TERM...AWB AVIATION...REV
AREA FORECAST DISCUSSION...CORRECTED
NWS QUAD CITIES IA IL
1147 PM CST MON NOV 19 2012 .AVIATION... SKIES HAVE CLEARED OVER MUCH OF THE AREA THIS EVENING...BUT VFR CIGS BASED AROUND 35HND FEET REMAIN EAST OF A LINE FROM JUST WEST OF KDBQ TO JUST WEST OF KMLI THROUGH KGBG. MODEL RH FIELDS SUGGEST THESE CLOUDS WILL NOT MOVE MUCH FURTHER EAST AND THE LATEST SATELLITE IMAGERY SHOWS THE EASTWARD PROGRESS SLOWING SIGNIFICANTLY. TO THE WEST CLEAR SKIES AND LIGHT WINDS NEAR A WEAK FRONT JUST MOVING INTO EASTERN IOWA HAVE CREATED FAVORABLE CONDITIONS FOR FOG. DENSE FOG WITH LIFR CIGS AND VSBYS LOOK REASONABLE AT KCID AND PROBABLY KBRL EARLY THIS MORNING. THE CLOUD COVER NEAR THE MISSISSIPPI RIVER SHOULD KEEP THE DENSE FOG OUT OF KDBQ AND KMLI. ONCE THE FRONT MOVES THROUGH THE AREA LOCATIONS THAT HAVE THE LIFR CONDITIONS SHOULD SLOWLY IMPROVE WITH VFR CONDITIONS EXPECTED AT ALL SITES AROUND 18Z TUESDAY. DLF && PREV DISCUSSION... /ISSUED 315 PM CST MON NOV 19 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS SEVERAL WEAK TROFS FROM THE WESTERN GREAT LAKES INTO THE ROCKIES. AT 850MB A MOISTURE PLUME EXTENDED FROM THE BAY OF CAMPECHE UP INTO CENTRAL IOWA. RADAR TRENDS THROUGH EARLY AFTERNOON SHOW A CONTINUED DECREASE OF THE PRECIPITATION AS THE OVERALL FORCING WEAKENS. AT THE SAME TIME...LOW CLOUDS HAD DEVELOPED ON THE EASTERN EDGE OF THE CLEARING AND WERE NOW OVER THE MID MISSISSIPPI VALLEY. 18Z SFC ANALYSIS HAS A VERY WEAK LOW ALONG THE OK/TX BORDER EAST OF KAMA WITH A TROF EXTENDING NORTH FROM THE LOW INTO NORTHERN MINNESOTA. A WEAK COLD FRONT RAN FROM NORTHWEST MINNESOTA INTO SOUTH DAKOTA. DEW POINTS WERE IN THE 40S AND 50S IN A BROAD MOISTURE PLUME FROM TEXAS INTO IOWA WITH 30S ACROSS THE REMAINDER OF THE MIDWEST AND PLAINS. SHORT TERM...TONIGHT AND TUESDAY... THE ONLY EXPLANATION FOR THE RAPID DEVELOPMENT OF THE LOW CLOUDS ACROSS THE CWFA SINCE LATE MORNING IS CONVERGENT FLOW AHEAD OF THE TROF. THIS CONVERGENCE CONTINUES THIS AFTERNOON SO THE CLOUDS ARE EXPECTED TO REMAIN ACROSS THE AREA. RADAR TRENDS SUGGEST THE POTENTIAL FOR SOME SPRINKLES/VERY LIGHT SHRA TO CONTINUE INTO THE LATE AFTERNOON HOURS AS WELL IN THE EASTERN CWFA. GOING ON THE ASSUMPTION THAT THE RAP TRENDS ARE CORRECT...THE OVERALL CONVERGENCE IS PROGGED TO WEAKEN THIS EVENING WHICH SHOULD ALLOW THE CLOUDS TO PARTIALLY BREAK UP IN THE WESTERN CWFA. IN THE EASTERN CWFA LINGERING SPRINKLES ARE POSSIBLE EARLY THIS EVENING. THE RAP TRENDS AFTER MIDNIGHT ARE DISTURBING. THE CONVERGENT FLOW IS PROGGED TO INCREASE AGAIN AND THE RAP IS INDICATING THAT A WEAK LOW WILL MOVE ALONG THE TROF INTO THE CWFA PRIOR TO SUNRISE. WITH PLENTIFUL LOW LEVEL MOISTURE IN PLACE THE CLOUDS ARE EXPECTED TO RE-DEVELOP OR FOG/STRATUS WILL DEVELOP IN THE CLEAR AREAS. THUS WILL ADD AREAS OF FOG IN THE WESTERN CWFA AND PATCHY FOG EAST WHERE THE CLOUDS ARE EXPECTED TO LINGER LONGER. I CANNOT RULE OUT THE POSSIBILITY OF A HEADLINE FOR THE FOG LATE TONIGHT INTO TUESDAY MORNING. HOW THE CLOUDS AND POTENTIAL FOG DEVELOP/EVOLVE LATE TONIGHT WILL BE THE KEY. IF ONE HAD TO ASSIGN A PROBABILITY IT IS CURRENTLY 1 IN 5 OR 1 IN 4 REGARDING A HEADLINE. ASSUMING THAT LOW CLOUDS/FOG DEVELOP LATE TONIGHT THEY WILL CONTINUE INTO TUESDAY MORNING. THE FOG SHOULD LIFT BY LATE MORNING WITH THE CLOUDS EXPECTED TO CLEAR OUT DURING THE AFTERNOON. THE RATE OF CLEARING ON TUESDAY IS A CONCERN GIVEN THE WEAK SUN. IT IS ENTIRELY POSSIBLE THAT THE CLOUDS MAY NOT CLEAR OUT UNTIL CLOSE TO SUNSET TUESDAY. IF THAT OCCURS...THE CURRENT MAX TEMPERATURES FOR TUESDAY ARE TOO WARM. ..08.. LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY... TUESDAY NIGHT AND WEDNESDAY...BOTH SFC AND UPPER RIDGING STILL ON TRACK TO GET PRESSED ACRS THE REGION THIS PERIOD AS WELL AS UNSEASONABLY MILD TEMPS. LIGHT WINDS AND CLEAR OUT OF CLOUDS WILL MAKE FOR A COOLER NIGHT TUE NIGHT WITH LOWS WELL DOWN IN THE 30S. DEPENDING ON TUE AFTERNOON CLOUD CLEAR OUT...THE LATER THE CLEARING TREND AND THUS REDUCING THE SFC MIX OUT DRYING...TUE NIGHT MAY BE AN IDEAL RADIATIONAL FOG SET UP ESPECIALLY ALONG AND EAST OF THE MS RVR. WILL HOLD OFF MENTION FOR NOW BUT FOLLOWING SHIFTS WILL HAVE TO ASSESS THIS POTENTIAL. AS FOR WED...TEMPORARY OMEGA BLOCK OVER STRENGTHENING WARMING LLVL RETURN FLOW STILL APPEAR ON TAP. EXTENT OF AVERAGED LLVL THERMAL DRAW BY THE MAJORITY OF THE NEW 12Z RUN MODELS AND MIXING UP INTO BASE ON BUILDING WARM WEDGE ALOFT SUPPORTS WIDESPREAD HIGHS IN THE UPPER 50S IN THE FAR NORTHEAST...TO THE MID 60S IN THE SOUTHWEST. UNSEASONABLY MILD WED NIGHT AND IF SOUTHERLY SFC WINDS CAN MAINTAIN AT 5-10 KTS...MANY AREAL TEMPS WILL BE HELD UP FROM DIPPING BELOW THE MID-UPPER 40S. BUT MAY PLAY IT COOLER IN CASE OF ANY SFC WIND DECREASE EVEN IF TEMPORARY. THURSDAY AND FRIDAY... INCOMING PACIFIC NW WAVE ENERGY/DEVELOPING CYCLONE ACRS THE NORTHERN PLAINS AND ASSOCIATED SFC FRONT PROJECTED BY LATER RUNS TO SWEEP THROUGH THE DVN CWA THU EVENING. ACTUAL FROPA OCCURRING ACRS THE MS RVR FROM THE WEST PROGGED BY ENSEMBLE MEAN NOW LOOKS TO OCCUR AROUND OR JUST AFTER 00Z FRI...THUS THE BULK OF THU THE DVN CWA TO BE IN BREEZY PRE-FRONTAL WARM SECTOR. STOUT INVERSION ALOFT AND INCREASE IN LOW-TO-MID LEVEL MOISTURE/CLOUDS COULD BE THE LIMITING FACTOR AND PREVENT A RECORD MILD THANKSGIVING. IF IT WERE NOT FOR THOSE FACTORS...SOME AREAS WOULD HIT 70 OR HIGHER. BUT WILL WITH A MORE CONSERVATIVE LOW TO MID 60S. STRENGTH OF LLVL FRONT ITSELF AND MID-UPPER LOW ROLLING ACRS THE UPPER MS RVR VALLEY SHOULD BE ENOUGH TO DEVELOP SOME SHOWERS JUST AHEAD OF THE FRONT THU AFTERNOON AND EVENING EVEN TAKING INTO ACCOUNT SOMEWHAT LIMITED MOISTURE RETURN INTO THE FROPA PROCESS. BUT IF LATER RUNS TREND WETTER...SOME MODERATE SHOWERS AN POSSIBLY EVEN A THUNDERSTORM MAY BE POSSIBLE THU AFTERNOON/EVENING. IT ALL DEPENDS ON ANY BUILD UP OF INSTABILITY IF IT CAN AS THU PROGRESSES. DEPENDING ON THE FRONTAL TIMING...LATE NIGHT SWITCH OVER TO LLVL COLD CONVEYOR COULD PLUNGE MUCH OF THE NORTHWEST HALF OF THE LOCAL FCST AREA INTO THE LOW TO MID 30S. FRIDAY STILL ON TRACK TO BE A MUCH COLDER BLUSTERY DAY IN SUBSIDING DRY SLOT OFF GRT LKS CYCLONE...WITH HIGHS HAVING TROUBLE GETTING OUT OF THE UPPER 30S TO LOWER 40S AS NORTHWEST WINDS GUST OVER 30 MPH. WRAP AROUND SNOW FLURRIES/SHOWERS MAY NOT BE ALL THAT FAR AWAY FROM THE LOCAL AREA ACRS SOUTHERN WI. IF SFC WINDS DECOUPLE UNDER CLEAR SKIES FRI NIGHT...LOWS COULD DIP INTO THE LOWER 20S TO EVEN UPPER TEENS IN SOME LOCATIONS BY EARLY SAT MORNING. SATURDAY THROUGH NEXT MONDAY...LATEST RUN OF THE MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST A QUICK RETURN TO PROGRESSIVE WESTERLIES/ FLATTENED FLOW PATTERN ACRS MUCH OF THE CONUS...THUS DRY AND THERMALLY MODERATING WX INTO SUNDAY AND SUNDAY NIGHT. HIGHS BY SUNDAY BACK INTO THE MID 40S TO NEAR 50 WITH SOME RETURN FLOW MIXING AND INSOLATION. AS FOR EARLY TO MID NEXT WEEK...NORTHERN HEMISPHERIC TELECONNECTIONS SUGGEST ENOUGH WAVE ENERGY/UPPER JET INFLUX DIGGING INTO THE WEST FOR AN EVENTUAL L/W TROF COMPLEX ACRS THE SOUTHWESTERN ROCKIES AND GRT BSN. MANY COMPLEX PHASING ISSUES TO BE RESOLVED THAT FAR OUT...BUT THE GENERAL SIGNAL OF A LOADED SOUTHWEST FLOW PATTERN ACRS THE WESTERN TO MID CONUS WITH COLD AIR TRYING TO DUMP DOWN THE PLAINS AND UPPER MIDWEST WHILE A WARM MOIST CONVEYOR STREAMS UP NORTHWARD TO THE LEE OF THE L/W TROF...COULD MAKE FOR A VERY INTERESTING MID TO LATE WEEK PERIOD. STAY TUNED. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
205 AM MST TUE NOV 20 2012 .SHORT TERM...(TODAY THROUGH THURSDAY NIGHT) ISSUED AT 205 AM MST TUE NOV 20 2012 LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW A RIDGE EXTENDING NORTH ACROSS THE CENTRAL AND HIGH PLAINS WITH A LARGE TROUGH JUST OFF THE PACIFIC NORTHWEST COAST. TODAY-WEDNESDAY...WITH SHORTWAVE RIDGE IN PLACE TODAY AND SW FLOW ALOFT AND LARGE SCALE SUBSIDENCE ON WEDNESDAY DRY CONDITIONS ARE EXPECTED. WITH WAA ON EASTERN EXTENT OF LEE TROUGH STRENGTHENING THE NEXT FEW DAYS...WE SHOULD SEE TEMPERATURES IN THE 70S...WITH MID TO UPPER 70S POSSIBLE ON WED. BREEZY CONDITIONS WILL ALSO DEVELOP OVER PARTS OF THE AREA WITH GUSTS 20-30 MPH OVER PARTS OF THE AREA THE NEXT FEW AFTERNOONS. SEE FIRE WEATHER SECTION REGARDING POSSIBLE RED FLAG CONDITIONS THE NEXT FEW DAYS. THURSDAY-THURSDAY NIGHT...A STRONG TROUGH WILL MOVE ALONG THE CANADA US BORDER ON WED NIGHT AND THURSDAY...WITH A WEAKER LESS AMPLIFIED SHORTWAVE MOVING ACROSS THE SOUTHERN STREAM. THE NORTHERN TROUGH WILL KICK A COLD FRONT SOUTH OVER THE CWA THURSDAY...WITH WINDY CONDITIONS EXPECTED THROUGH WED AFTERNOON. WE COULD SEE WIND ADVISORY CRITERIA MET WITH BL WINDS 27-29KT AND H85 WINDS AROUND 40KT. ITS STILL TOO EARLY FOR AN NPW...HOWEVER I DID INCREASE WINDS TO REFLECT CURRENT THINKING. BEYOND FORCING IMMEDIATELY ALONG FRONT THE BEST LARGE SCALE ASCENT IS WELL NORTH AND SOUTHEAST. THE AIR MASS ALSO REMAINS VERY DRY ACROSS CWA...SO IM NOT ANTICIPATING ANY PRECIP. WITH FROPA DURING THE DAY HIGH TEMPS THU ARE TRICKY...HOWEVER THEY STILL SHOULD BE ABOVE NORMAL WITH A GRADIENT OF UPPER 50S IN THE NORTH TO MID/UPPER 60S IN THE SOUTH. NEAR TO BELOW NORMAL LOW TEMPS ARE EXPECTED THU NIGHT BEHIND THE FRONT WITH VALUES RANGING FROM THE UPPER TEENS TO MID 20S. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 205 AM MST TUE NOV 20 2012 AT LEAST EARLY ON MODELS ARE CONSISTENT WITH THE PREVIOUS FORECAST. COOLEST DAY WILL BE ON FRIDAY WITH MODERATION FOR SATURDAY. THEN CHANGES AND INCONSISTENCIES BEGIN AFTER THAT. NEWER MODEL DATA...ESPECIALLY THE ECMWF...IS NOW MORE PROGRESSIVE AND NOT AS STRONG WITH INCOMING UPPER TROUGH AT THE BEGINNING OF NEXT WEEK. GFS IS MUCH FASTER AND OLDER CANADIAN WAS MORE IN LINE WITH THE ECMWF. IN ADDITION THE MODEL DATA BRINGS IN NOT JUST ONE SHORTWAVE BUT A SERIES OF SHORTWAVE TROUGHS IN THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME PERIOD. THIS NEWER DATA IS FITTING THE PATTERN WE HAVE BEEN SEEING THIS SEASON AND IN FACT THIS YEAR. THE TROUGH DOES NOT COME THROUGH IN ONE NICE ORGANIZED SYSTEM BUT IN A SERIES OF SHORTWAVE TROUGHS. ENSEMBLE DATA SUPPORTS THE MORE PROGRESSIVE AND MULTIPLE SHORTWAVE SOLUTION AS WELL. THESE MULTIPLE SHORTWAVES HAVE TENDED TO SCOUR OUT THE DEEPER MOISTURE THAT THE MODELS THINK IS THERE. BELIEVE THAT THIS IS THE CASE HERE AS WELL. PLUS THE FRONT COMES THROUGH RATHER EARLY AND BY SUNDAY NIGHT IS A GREAT DISTANCE SOUTH OF THE AREA. NO SIGNIFICANT JET LIFT LOOKS TO BE INVOLVED AS WELL. AS A RESULT OF ALL THIS AND COLLABORATION...KEPT THE SMALL AREAS OF SLIGHT CHANCE POPS SUNDAY NIGHT AND MONDAY THE INIT GAVE ME AND REDUCED THE CHANCE POPS FOR MONDAY NIGHT DOWN TO SLIGHT CHANCE. BIG DIFFERENCES SHOWING UP IN THE LOW LEVEL THERMAL FIELD BEGINNING ON SUNDAY. THE ECMWF WAS NOT AS COLD AS THE FRIGID GFS. THE ECMWF TENDED TO BE IN THE MIDDLE OF THE ROAD AND ALSO MATCHED UP WELL WITH THE CRH_INIT SO LEFT THE TEMPERATURES ALONE AS RESULT OF THAT AND THE MODEL DIFFERENCES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 429 PM MST MON NOV 19 2012 VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD AS A RIDGE OF HIGHER PRESSURE MOVES EAST OF THE ROCKIES AND AMPLIFIES OVER THE CENTRAL HIGH PLAINS ON TUESDAY. HIGH CLOUDS WILL DISSIPATE WITH SKIES BECOMING CLEAR AFTER 06Z. LIGHT AND VARIABLE WINDS WILL BECOME LIGHT SOUTHWEST AFTER 06Z AND WILL BECOME GUSTY AFTER 18Z TUESDAY AFTERNOON AS A LEE TROUGH BEGINS TO DEEPEN ALONG THE FRONT RANGE. && .FIRE WEATHER... ISSUED AT 205 AM MST TUE NOV 20 2012 RH VALUES THIS AFTERNOON WILL RANGE FROM 15 TO 20 PERCENT. WITH WIND GUSTS 20-25 MPH WE WILL BE VERY CLOSE TO RFW CRITERIA. FOR NOW I AM NOT CONFIDENT WE WILL MEET THE 3HR REQUIREMENT...NO RFW PLANNED FOR NOW. CRITICAL FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE WED AFTERNOON WHEN RH VALUES BETWEEN 10 AND 20 PERCENT ARE EXPECTED ALONG AND NORTHWEST OF A LINE FROM OBERLIN TO LEOTI KS. WINDS ARE GOING TO BE LIGHTER IN THE WEST...WITH STRONGEST WINDS CURRENTLY WHERE RH VALUES ARE FORECAST TO BE HIGHER. MOST LOCATIONS SHOULD BE OUTSIDE OF RFW CRITERIA OTHER THAN A NARROW CORRIDOR SOUTH OF INTERSTATE 70 WHERE THERE COULD SEE A CROSSOVER OF RH/WIND. THIS IS GOING TO BE CLOSE...SO ITS WORTH MONITORING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...LOCKHART FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1131 PM CST MON NOV 19 2012 .UPDATE... ISSUED AT 1131 PM CST MON NOV 19 2012 THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE. UPDATE ISSUED AT 849 PM CST MON NOV 19 2012 ALTHOUGH NOT REGISTERED THROUGH SURFACE OBSERVATIONS...THE KVWX RADAR HAS BEEN DETECTING ENOUGH 20+ DBZ RETURNS AT 0.5 DEGREE ELEVATION TO WARRANT THE POTENTIAL FOR AT LEAST ISOLATED SHOWERS OR SPRINKLES REACHING THE SURFACE. WITH THIS IN MIND AND WITH THE ASSISTANCE OF THE HRRR 1KM REFLECTIVITY GUIDANCE...ADDED A SMALL POP/WEATHER CHANCE MAINLY OVER THE WEST KENTUCKY PENNYRILE THROUGH 05Z /11 PM CST/. UPPER AIR CHARTS CONTINUE TO SHOW A SERIES OF MINOR WAVES ROTATING INTO THE BROAD TROUGH WITH THE BASE WEST OF THE WFO PAH FORECAST AREA. DESPITE FLUCTUATIONS IN CLOUD COVER FOR THE REMAINDER OF TONIGHT...ADJUSTED THE NET OPAQUE CLOUD COVER TO MOVE THE CLOUDS WITH THE MEAN FLOW THIS EVENING AND OVERNIGHT. GIVEN THAT SCENARIO...HAD TO INCREASE MINIMUM TEMPERATURES 3-4 DEGREES. IN ADDITION...THE SOUTHERLY WIND COMPONENT SHOULD PERSIST FURTHER INTO THE NIGHT AS AN AGEOSTROPHIC RESPONSE TO THE APPROACHING SHORTWAVES. THIS SHOULD HELP BUOY TEMPERATURES AT MOST LOCATIONS OVERNIGHT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 149 PM CST MON NOV 19 2012 CLOUDS AND WEAK SHORT WAVE MOVING THROUGH THE CWA AT THIS TIME. WATER VAPOR IMAGERY CLEARLY SHOWS DRIER AIR WORKING INTO SEMO WHICH IS HELPING TO DRY UP ANY PRECIPITATION LEFT FROM THIS MORNING. MAY HAVE HAD A FEW SPRINKLES OVER RIPLEY AND CARTER COUNTIES...BUT THAT WAS ABOUT IT. THE CLOUDS HAVE AFFECTED TEMPERATURES WITH SEMO REMAINING AROUND 60. THIS CLOUD BANK WILL MOVE ACROSS THE AREA TONIGHT WHICH SHOULD KEEP TEMPERATURES UP COMPARED TO LAST NIGHT. KEPT THE DRY FORECAST GOING AS THE LOWEST 5K FT REMAIN DRY. A SHORTWAVE SEEN ON SATELLITE OVER THE NORTHERN PLAIN WILL MOVE THROUGH OUR AREA ON TUESDAY IN THE FORM OF A WEAK COLD FRONT. THE FRONT SHOULD MOVE THROUGH DURING THE LATE MORNING INTO THE AFTERNOON HOURS WHICH SHOULD ALLOW FOR DECENT HEATING AHEAD OF THE FRONT EXCEPT FOR THE EXTREME EASTERN SECTIONS AS THE CLOUDS ARE EXPECTED TO HANG ON THERE INTO THE EVENING HOURS. NO PRECIPITATION IS EXPECTED WITH THIS FRONTAL PASSAGE. DRIER AIR MOVING MOVES IN ON WEDNESDAY AND WITH CLEAR SKIES AND LIGHT WIND SOME FOG POSSIBLE OVER WESTERN KENTUCKY WEDNESDAY NIGHT INTO THURSDAY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 149 PM CST MON NOV 19 2012 WE WILL START OUT ON THURSDAY WITH AN UPPER LEVEL RIDGE OVERHEAD...THAT WILL BE MOVING EASTWARD WITH TIME. THE 12Z GFS CONTINUES TO BE FASTER...THAN PREVIOUS RUNS AND THE ECMWF IN MOVING THE RIDGE EAST AS THE NEXT SHORTWAVE TROUGH APPROACHES FROM THE WEST. BY 00Z FRI...THE 00Z ECMWF STILL HAS THE UPPER RIDGE OVER THE CWA WITH THE IMPENDING SHORTWAVE ACROSS EASTERN KS/OK. THE 12Z GFS HAS THE UPPER RIDGE AXIS OVER THE APPALACHIANS AT THAT SAME TIME WITH THE SHORTWAVE TROUGH KNOCKING ON OUR WESTERN FRINGES. THE GFS HAS SPENT SEVERAL RUNS TRYING TO FIGURE OUT WHETHER THE WESTERN FRINGES OF THE CWA WILL SEE ANY PRECIP PRIOR TO 00Z FRIDAY...BUT CONSENSUS SAYS THAT THINGS WILL PROBABLY STAY DRY. IN FACT...THE 00Z/12Z ECMWF KEEPS US DRY THROUGH 06Z AND THIS MODEL HAS BEEN FLIP FLOPPING ON THAT FOR A WHILE NOW TOO...WHETHER TO START PRECIP ON THURSDAY EVENING OR OVERNIGHT. THE GFS INDICATE RAIN SHOWERS SHOULD BE MOVING IN FROM THE WEST DURING THE EVENING HOURS ON THANKSGIVING...MOVING EAST DURING THE OVERNIGHT HOURS. THE GFS HAS HAD A PROBLEM OVER THE PAST 2 DAYS...FIGURING OUT HOW LONG THE PRECIP WAS GOING TO LINGER ON FRIDAY. RIGHT NOW...THE 12Z GFS INDICATE THAT FRIDAY MORNING MIGHT END UP BEING DRY. THE SLOWER 00Z/12Z ECMWF STILL HOLDS ONTO RAIN CHANCES THOUGH THROUGH THE MORNING HOURS...AT LEAST IN THE SOUTHEASTERN HALF. THINK THE GOING FORECAST RESEMBLES A GOOD BLEND OF SEVERAL DAYS OF MODEL RUNS AND IS A GOOD COMPROMISE TO ALL OF THOSE RUNS OF THE GFS/ECMWF. THE BOTTOM LINE: CHANCES FOR RAIN WILL BEGIN TO INCREASE AFTER 00Z FRIDAY...AND CONTINUE THROUGH THE NIGHT...AND BEGIN TO TAPER OFF THROUGHOUT THE MORNING HOURS ON FRIDAY. RAINFALL AMTS LOOK TO BE RATHER LIGHT AT THIS POINT...AND GFS ENSEMBLES SUPPORT THIS AS WELL. ON FRIDAY...A NORTHERN STREAM SHORTWAVE WILL BE MOVING ACROSS THE NORTHERN PLAINS AND DOWN INTO THE UPPER MIDWESTERN STATES...AND BRING A NICE POCKET OF COLD AIR WITH IT. AS HAS BEEN THE CASE FOR SEVERAL DAYS NOW...THE ECMWF CONTINUES TO BE DEEPER WITH THIS TROUGH AND HENCE BRINGS THE COLDER AIR FURTHER SOUTH. IN FACT...IT IS A PRETTY POTENT POCKET OF COLD AIR...WITH THE ECMWF SHOWING H850 TEMPS AROUND -11C DEG ACROSS OUR FAR NORTH. HOWEVER...IT APPEARS AS THOUGH THE 12Z GFS HAS LOCKED INTO SOMETHING NOW SINCE IT TOO BRINGS COLDER AIR FURTHER SOUTH. IT IS NOT QUITE LIKE THE ECMWF BUT AT LEAST IT IS CLOSER. PLUS THE GFS ENSEMBLES ARE COLDER THAN THE OPERATIONAL GFS. WE WILL DEFINITELY SEE A DROP IN TEMPS ON FRIDAY AS COLD AIR ADVECTION WILL BE WELL UNDERWAY WITH BRISK NORTHERLY FLOW AT THE SFC. IN FACT...MODELS HAVE BEEN TRENDING COLDER WITH EACH MODEL RUN...SO WILL LOWER HIGHS. HIGHS ON SATURDAY WILL BE QUITE COOL FROM WHAT WE HAVE BEEN USED TO THIS WEEK AND COULD END UP BEING 10 DEG COLDER THAN ON FRIDAY...AS HIGH PRESSURE BUILDS IN AT THE SFC. THE COLDEST TEMPS WILL BE IN OUR EASTERN SECTIONS...WHERE SOME OF THE GUIDANCE IS GIVING HIGHS ONLY IN THE LOW 40S. THERE IS NOW QUITE A BIT OF DIFFERENCE BTWN THE GFS AND ECMWF FOR THE SYSTEM ON SUNDAY AND MONDAY. THE 12Z GFS SHOWS THE HIGH MOVING EAST AS A MOISTURE STARVED COLD FRONT MOVES INTO THE REGION ON SUNDAY. HOWEVER...ON SUNDAY NIGHT...MOISTURE BEGINS TO RETURN NORTH IN EARNEST AND A WARM FRONT STARTS DEVELOPING TO OUR S/SW...WHICH ENDS UP CAUSING SOME OVERRUNNING PRECIP ACROSS OUR SOUTHERN AREAS LATE SUNDAY NIGHT AND INTO MONDAY. THE 00Z ECMWF IS SLOW TO MOVE THE SFC HIGH EAST BUT FINALLY DOES SO SUNDAY AFTERNOON/NIGHT...ALLOWING FOR SOUTHERLY FLOW TO TAKE OVER AND MOISTURE SLOWLY INCREASE OVER THE AREA. HOWEVER...ANY CHANCES FOR RAIN LOOK TO HOLD OFF UNTIL MONDAY/MONDAY NIGHT WITH THE ARRIVAL OF THE FRONT. STILL A LOT OF UNCERTAINTY HERE BUT WHAT DOES SEEM PROBABLE AT THIS POINT IS SEEING AN INCREASE IN TEMPERATURES ON SUNDAY AND MONDAY...BUT WE WILL HAVE TO SEE WHAT HAPPENS WITH FUTURE RUNS ON THE NEXT CHANCE FOR PRECIP. FOR NOW...HAVE ADDED A CHANCE FOR MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1131 PM CST MON NOV 19 2012 CEILINGS ARE EXPECTED TO FILL IN IN THE 4-6KFT LAYER ACROSS ALL SITES BY MORNING. CEILINGS MAY SLIGHTLY LOWER THROUGH THE DAY AS A WEAK COLD FRONT APPROACHES THE AREA. THIS FRONT IS LITTLE MORE THAN A WIND SHIFT AND A WEAK ONE AT THAT...SO IT WILL BE OF LITTLE CONSEQUENCE TO THE TAFS. WILL SHOW A SHIFT FROM WEST SOUTHWEST TO NORTH NORTHWEST AT ALL SITES FROM 21Z-23Z...BUT THIS TIMING COULD BE EARLIER OR LATER. WILL HAVE TO WATCH FOR SOME CEILINGS DROPPING JUST INTO MVFR TERRITORY NEAR THE FRONT...BUT FOR NOW DO NOT SEE ENOUGH EVIDENCE IN THE LATEST GUIDANCE TO INSERT IT IN THE FORECAST. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...DRS SHORT TERM...PS LONG TERM....CW AVIATION...DRS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
338 AM CST TUE NOV 20 2012 .SHORT TERM... CHALLENGE FOR THE FORECAST IN THE SHORT TERM INCLUDES WARM TEMPS AND THEN LOW PRESSURE SYSTEM TRACKING ACROSS THE AREA THANKSGIVING DAY AND NIGHT. MODELS IN FAIR AGREEMENT THUS USED A BLEND THROUGH THE MID WEEK. SOME UNCERTAINTY WITH COVERAGE AND DEPTH OF FOG DEVELOPMENT THIS MORNING AND ITS EVOLUTION TODAY. HRRR MODEL DEVELOPS WIDE AREA OF FOG OVER THE MN PINES AND LAKES AND THEN SLOWLY ADVECTS IT TO THE WEST AND NORTH OVER THE VALLEY DURING THE DAY TODAY. THIS SCENARIO WOULD DRASTICALLY LOWER FORECASTED HIGHS TODAY...THOUGH HRRR DID INITIALIZE WITH MORE FOG AT 08Z THAN WHAT IS CURRENTLY SEEN IN SFC OBS. CURRENT THINKING IS THAT FOG WILL BE LESS DENSE AND ABLE TO ERODE THIS MORNING AND ALLOW GOOD SOLAR SOME WAA ON SOUTH TO SOUTHEAST WINDS ON THE BACKSIDE OF THE DEPARTING HIGH TO ALLOW HI TEMPS TO REACH MID 40S. LOW LEVEL WARM ADVECTION CONTINUES OVERNIGHT WITH GOOD MIXING KEEPING TEMPS UP NEAR THE FREEZING MARK WEDNESDAY MORNING. THESE WARM LOWS WILL BE SETTING THE STAGE FOR HIGHS IN THE MID 50S SOUTH... NEAR THE RECORD OF 58 AT FARGO... TO NEAR 50 ALONG THE SNOW LINE AS 850MB TEMPS RANGE FROM 10C IN THE NORTH TO 14 C IN THE SOUTH. MODELS IN GOOD AGREEMENT WITH SFC LOW PRESSURE TO TRACK ACROSS THE AREA EARLY THURSDAY MORNING. BEHIND THE ATTACHED COLD FRONT CHC OF RAIN IN THE MORNING WILL GIVE WAY TO SNOW FROM NW TO SE AS THE COLUMN COOLS. TEMPS LIKELY TO FALL DURING THE DAY AS THE COLD AIR SPILLS INTO THE REGION ON THE NW WINDS. A MIXED PCPN TYPE IS POSSIBLE BEFORE MEASURABLE SNOWFALL STARTS TO ACCUMULATE ACROSS THE NORTHERN HALF OF THE CWFA THURSDAY AFTERNOON AND EVENING. BY 00Z FRI ALL PCPN WILL BE FROZEN WITH SNOW LIKELY ACROSS THE N RRV AND INTO NW MN AS THE DEFORMATION SNOW BAND ORGANIZES OVERNIGHT. WINDS WILL ALSO BE A FACTOR WITH THIS SYSTEM AS STRONG TO BLUSTERY CONDITIONS ARE EXPECTED WITH 40 TO 50KTS AT 850MB THURSDAY NIGHT COMBINED WITH THE AFOREMENTIONED SNOW COULD TRAVEL DIFFICULT ACROSS PORTIONS OF THE CWFA. GIVEN THE HOLIDAY AND TRAVEL PLANS INDIVIDUALS SHOULD CONTINUE TO MONITOR FUTURE FORECASTS. .LONG TERM (FRIDAY-MONDAY)...MODELS ARE IN GOOD AGREEMENT WITH TRENDS BUT A BIT DIFFERENT WITH DETAILS. THE GENERAL IDEA IS FOR NORTHWEST FLOW ALOFT WITH A STRONGER SYSTEM/COLD FRONT SATURDAY NIGHT OR SUNDAY. THE MAIN ISSUE WILL BE WINDS WITH THE FROPA AND THEN WELL BELOW NORMAL TEMPERATURES BEHIND THIS FEATURE (WITH NOT MUCH SNOWFALL). && .AVIATION... HIGH PRESSURE ALLOWING PATCHY TO DENSE FOG FORMATION AND IFR CONDITIONS TO DEVELOP AT FAR...TVF AND BJI. DVL ALREADY SEEING S WINDS AND SHOULD REMAIN AT VFR. GFK JUST WEST OF THE FOG FOR NOW...IF IT EXPANDS...A GOOD POSSIBILITY IN THE NEXT 6 HR...GFK TO SEE IFR. IFR CONDITIONS TO LIFT TO MVFR IN LATE MORNING BEFORE SCT OUT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ JK/TG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 AM CST TUE NOV 20 2012 .SHORT TERM...TODAY THROUGH THANKSGIVING 326 AM CST TUE NOV 20 2012 AT 3 AM...A PACIFIC COLD FRONT WAS MOVING INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA. AHEAD OF THIS FRONT...WIDESPREAD DENSE FOG HAS DEVELOPED ACROSS MUCH OF NORTHEAST IOWA AND PARTS OF SOUTHEAST MINNESOTA. AS THIS FRONT MOVES THROUGH...IT HAS BEEN LESSENING THE DEPTH OF THE FOG. THIS HAS RESULTED IN SOME IMPROVEMENT IN THE VISIBILITIES IN THE WAKE OF THIS FRONT. NOT QUITE SURE WHAT THIS FOG IS GOING TO DO ONCE IT MOVES INTO WESTERN WISCONSIN. WILL IT JUST BE A DECK OF STRATUS OR WILL WE SEE RAPID DEVELOPMENT OF DENSE FOG. DUE TO THIS UNCERTAINTY HELD OFF EXPANDING THE DENSE FOG ADVISORY FOR NOW. FOR TODAY EXPECT TO SEE THE LOW CLOUDS AND FOG WILL DISSIPATE THIS MORNING. THIS WILL LEAVE AFTERNOON MAINLY SUNNY. SINCE THIS FRONT IS A PACIFIC ONE...TEMPERATURES SHOULD ONLY BE A FEW DEGREES COOLER THAN MONDAY. ON WEDNESDAY...SOUTHWEST WINDS ALOFT WILL BRING VERY WARM AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. 925 MB TEMPERATURES CLIMB FROM 8C THIS AFTERNOON TO 14C BY WEDNESDAY AFTERNOON. THE WARM AIR BEING BROUGHT ISENTOPICALLY OFF OF THE HIGH PLAINS WILL RESULT IN THE DEVELOPMENT OF A STRONG CAP. THIS WILL INHIBIT THE DEVELOPMENT OF ANY PRECIPITATION. HIGH TEMPERATURES WILL BE IN THE MID AND UPPER 50S NORTH OF INTERSTATE 94 CORRIDOR /WHICH WILL BE CLOSE TO SOME RECORDS/. MEANWHILE THE REMAINDER OF THE AREA WILL BE IN THE LOWER AND MID 60S. ON THANKSGIVING...BOTH THE GFS AND ECMWF SUGGEST THAT A SHORT WAVE TROUGH WILL AFFECT SOUTHWEST WISCONSIN AND NORTHEAST IOWA. SOUNDINGS SUGGEST THAT THE AIRMASS WILL MOISTEN ENOUGH THAT THERE COULD BE SOME ELEVATED SHOWERS MOVE THROUGH THIS AREA. DUE TO THIS BEING A CONSISTENT SIGNAL...KEPT A LOW /20 PERCENT/ PRECIPITATION PROBABILITY IN THE FORECAST. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY 326 AM CST TUE NOV 20 2012 ON THURSDAY NIGHT AND FRIDAY...THE 20.00Z MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH WILL MOVE EAST THROUGH THE AREA. THIS SYSTEM WILL USHER IN MUCH COOLER AIR INTO THE REGION. TEMPERATURES WILL RUN NEAR TO SLIGHTLY BELOW NORMAL FROM FRIDAY INTO THE WEEKEND. THE MODELS ALSO SHOW THAT THERE WILL DEEP ENOUGH MOISTURE FOR A CHANCE OF SNOW ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. MEANWHILE SOUTH OF THIS CORRIDOR...THE BUFKIT SOUNDINGS SHOW SOME WEAK OMEGA IN THE DENDRITIC GROWTH REGION AND THERE IS STEEP LAPSE RATES /AROUND 8C/KM / BETWEEN THE 950-850 MB. DUE TO THIS...INCLUDED SOME SCATTERED FLURRIES FOR THIS AREA FROM 29.09Z AND 29.12Z. GUSTY NORTHWEST WINDS AT 15 TO 20 KNOTS WILL PRODUCE WIND CHILLS FROM THE TEENS TO MID 20S. FOR EARLY NEXT WEEK AND BEYOND...UNCERTAINTY IS MUCH HIGHER THAN AVERAGE DUE TO THE FOLLOWING REASONS... 1. MADDEN JULIAN OSCILLATION /MJO/ - SEVERAL MODELS INCLUDING SOME RUNS OF THE ECMWF AND GFS TRY TO BRING A STRONG MJO SIGNAL INTO THE WESTERN PACIFIC BY EARLY NEXT WEEK. HOWEVER DURING THE PAST 3 DAYS...200 MB VELOCITY POTENTIAL ANOMALIES HAVE DRAMATICALLY DECREASED. IT WILL INTERESTING OVER THE WEEKEND WHETHER THIS OSCILLATION STRENGTHENS AS IT MOVES OVER 30C WATER IN THE WESTERN PACIFIC. 2. PHASE OF THE NORTH ATLANTIC OSCILLATION /NAO/ - FOR THE PAST WEEK THE MODELS HAVE BEEN STRUGGLING ON WHEN THE NAO WILL ONCE AGAIN BECOME NEGATIVE. CPC/S SPAGHETTI PLOT CONTINUES TO SHOW A WIDE RANGE OF SOLUTIONS FROM -1.5 TO 1. LOOKING AT THE 150 MB WIND ANOMALIES AND ALSO STRATOSPHERIC TEMPERATURES...DO NOT SEE ANY INDICATION OF A BLOCKING RIDGE DEVELOPING ANYWHERE IN THE NORTHERN HEMISPHERE. 3. CLIMATE MODELS - BOTH THE CFS VERSION 2 AND THE NORTH AMERICAN ENSEMBLE FORECASTING SYSTEM /NAEFS/ SHOW ABOVE- NORMAL TEMPERATURES FOR THE DAY 8 TO 14 TIME PERIOD. AS A RESULT...ANY COLD PERIOD SHOULD BE RATHER SHORT. THIS IS INCONSISTENT WITH SOME OF THE MODELS WHICH SHOW THAT SHOW A PERSISTENT TROUGH OVER THE AREA. WITH MIXED SIGNALS ACROSS THE GLOBE...VERY CAUTIOUS OF GRABBING ONTO ANY ONE MODEL SOLUTION...THUS...WILL KEEP PRECIPITATION PROBABILITIES LOW BEYOND DAY 5 UNTIL THERE IS A COHERENT DAY TO DAY SIGNAL. && .AVIATION... 1035 PM CST MON NOV 19 2012 FOG IS GOING TO BE A BIGGER PLAYER IN THE FORECAST THAN FIRST THOUGHT. MESO MODELS CONTINUE TO POINT TO A RELATIVELY MOIST BOUNDARY LAYER UNDER AN INVERSION TONIGHT...WITH LIGHT SFC WINDS. FOG HAS ALREADY BEGUN TO DEVELOP WEST OF A CLOUD MASS THAT SAT ACROSS MOST OF WI...PER LATEST FOG/STRATUS SATELLITE IMAGERY. IN THE CLEAR REGION WEST OF THERE VSBYS HAVE ALREADY FALLEN BELOW 2 MILES IN MANY AREAS. BELIEVE VSBYS WILL DROP BELOW 1 MILE AT TIMES OVERNIGHT. PASSING SFC FRONT SHOULD USHER IN SOME DRIER AIR BY 12Z AT KRST...WHICH SHOULD HELP IMPROVE VSBYS. SOME NUMERICAL MODELS SUGGEST THAT FOG...POTENTIALLY DENSE...WOULD PERSIST THROUGH 15Z AT KRST. NOT BUYING THAT AT THIS MOMENT. A PERIOD OF IFR/LIFR LOOKS LIKELY AT KRST...AND PROBABLE AT KLSE. CAN/T RULE OUT THAT A DENSE FOG ADVISORY WILL BE NEEDED FOR PORTIONS OF THE REGION FOR EARLY TUE MORNING. WITH THE FOG WILL COME SOME STRATUS...ESPECIALLY AS THE FOG STARTS TO LIFT. RAP BUFKIT SOUNDINGS WOULD SCATTER OUT ANY CIGS BETWEEN 15-17Z. NOT ALL IS CLEAR CUT WITH VSBYS AND CIGS OVERNIGHT THOUGH...SO A CLOSE WATCH ON CONDITIONS WILL HAVE TO CONTINUE AND UPDATES MADE AS NEEDED. HIGH PRESSURE GRADUALLY BUILDS IN TUE AFTERNOON...BUT QUICKLY SLIDES SOUTHEAST OVERNIGHT. PRESSURE GRADIENT INCREASE BEHIND THE HIGH...AND COULD SEE SOME INCREASE IN WINDS TOWARD 12Z WED AS A RESULT. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 7 AM-7 AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE THE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 117 AM CST TUE NOV 20 2012 WI...NONE. MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ079-087- 088-094>096. IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011- 018-019-029-030. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION.....RIECK CLIMATE......JONES/DB/AJ/BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
227 AM CST TUE NOV 20 2012 .SHORT TERM...THIS MORNING 227 AM CST TUE NOV 20 2012 THE DENSE FOG THAT FORMED NEAR MIDNIGHT OVER WESTERN PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAS BEEN SPREADING WESTWARD. AS A RESULT...HAVE EXPANDED THE ADVISORY TO INCLUDE THE COUNTIES BORDERING THE MISSISSIPPI RIVER. WILL CONTINUE TO WATCH SATELLITE AND OBSERVATIONAL TRENDS...BUT THERE IS CONCERN THAT SOME WISCONSIN COUNTIES MAY EVENTUALLY BE NEEDED IN THE ADVISORY TOO. WILL EVALUATE THE NEED FOR FURTHER EXPANSION DURING THE NEXT HOUR. ALSO...THE LAST FEW HRRR RUNS WITH THE VISIBILITY PROGS SUGGEST THIS FOG MAY TAKE LONGER TO DISSIPATE THAN PREVIOUSLY EXPECTED AT MIDNIGHT. INITIAL THOUGHT WAS THAT THIS COLD FRONT COMING THROUGH SOUTHEAST MINNESOTA AND NORTHEAST IOWA...NOTED BY WEST WINDS AT ROCHESTER...DODGE CENTER AND PRESTON...WOULD HELP CLEAR UP THE FOG. THIS HAS OCCURRED AT DODGE CENTER AND AS WELL FARTHER SOUTH AT MASON CITY IN IOWA. HOWEVER...IT APPEARS IT IS TAKING AWHILE AT AUSTIN TO DO SO. THUS...THINKING THE FOG MAY BE DEEPER AND MORE RESILIENT TO CLEARING. PLUS...POST FRONTAL...TEMPERATURES AND DEWPOINTS DO NOT DROP ALL THAT MUCH. YOU HAVE TO GO BACK INTO SOUTHWEST MINNESOTA TO GET DEWPOINTS BELOW FREEZING. HRRR VISIBILITY PROGS SUGGEST THE FOG COULD STICK AROUND UNTIL 16Z OR SO. AS A RESULT...HAVE PLAYED THE PESSIMISTIC ROUTE AND EXTENDED THE ADVISORY TO 16Z. .LONG TERM... 250 PM CST MON NOV 19 2012 SYSTEM DEPARTS ON FRIDAY...WITH CYCLONIC FLOW ACROSS THE AREA. TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS MAINLY IN THE 30S. MAIN PRECIPITATION CHANCE WILL BE ACROSS THE FAR NORTH. OTHERWISE...REMAINDER OF THE PERIOD WILL BE DOMINATED BY SEASONAL TO BELOW NORMAL TEMPERATURES. BEST CHANCE FOR ANY PRECIPITATION LOOKS BE ON MONDAY...BUT MODELS SHOWING SOME DIFFERENCES WITH A DEVELOPING TROUGH ACROSS THE CENTRAL CONUS. 19.12Z ECMWF SHOWS THIS FEATURE WITH CYCLOGENESIS OCCURRING...WHILE THE GFS KEEPS FLOW MORE ZONAL. IF THE ECMWF DOES VERIFY WILL HAVE TO WATCH THIS SYSTEM FOR PERIODS BEYOND MONDAY. && .AVIATION... 1035 PM CST MON NOV 19 2012 FOG IS GOING TO BE A BIGGER PLAYER IN THE FORECAST THAN FIRST THOUGHT. MESO MODELS CONTINUE TO POINT TO A RELATIVELY MOIST BOUNDARY LAYER UNDER AN INVERSION TONIGHT...WITH LIGHT SFC WINDS. FOG HAS ALREADY BEGUN TO DEVELOP WEST OF A CLOUD MASS THAT SAT ACROSS MOST OF WI...PER LATEST FOG/STRATUS SATELLITE IMAGERY. IN THE CLEAR REGION WEST OF THERE VSBYS HAVE ALREADY FALLEN BELOW 2 MILES IN MANY AREAS. BELIEVE VSBYS WILL DROP BELOW 1 MILE AT TIMES OVERNIGHT. PASSING SFC FRONT SHOULD USHER IN SOME DRIER AIR BY 12Z AT KRST...WHICH SHOULD HELP IMPROVE VSBYS. SOME NUMERICAL MODELS SUGGEST THAT FOG...POTENTIALLY DENSE...WOULD PERSIST THROUGH 15Z AT KRST. NOT BUYING THAT AT THIS MOMENT. A PERIOD OF IFR/LIFR LOOKS LIKELY AT KRST...AND PROBABLE AT KLSE. CAN/T RULE OUT THAT A DENSE FOG ADVISORY WILL BE NEEDED FOR PORTIONS OF THE REGION FOR EARLY TUE MORNING. WITH THE FOG WILL COME SOME STRATUS...ESPECIALLY AS THE FOG STARTS TO LIFT. RAP BUFKIT SOUNDINGS WOULD SCATTER OUT ANY CIGS BETWEEN 15-17Z. NOT ALL IS CLEAR CUT WITH VSBYS AND CIGS OVERNIGHT THOUGH...SO A CLOSE WATCH ON CONDITIONS WILL HAVE TO CONTINUE AND UPDATES MADE AS NEEDED. HIGH PRESSURE GRADUALLY BUILDS IN TUE AFTERNOON...BUT QUICKLY SLIDES SOUTHEAST OVERNIGHT. PRESSURE GRADIENT INCREASE BEHIND THE HIGH...AND COULD SEE SOME INCREASE IN WINDS TOWARD 12Z WED AS A RESULT. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 6AM-6AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 227 AM CST TUE NOV 20 2012 WI...NONE. MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ079-087- 088-094>096. IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011- 018-019-029-030. && $$ SHORT TERM...AJ LONG TERM....RABERDING AVIATION.....RIECK CLIMATE......JONES/DB/AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1035 PM CST MON NOV 19 2012 .SHORT TERM... 920 PM CST MON NOV 19 2012 QUICK UPDATE TO ADD FOG MENTION TO THE FORECAST FOR TONIGHT. THIS MORNING/S RAINS...WHILE ONLY MINIMAL IN AMOUNTS...DID HELP ADD SOME MOISTURE TO THE BOUNDARY LAYER. SFC WINDS ARE BECOMING LIGHT AND SOME FUZZ IS STARTING TO DEVELOP OVER PARTS OF IOWA...JUST WEST OF THE CLOUD EDGE. BUFKIT SOUNDINGS SUGGEST THAT THE LOW LEVEL MOISTURE WILL REMAIN IN PLACE OVERNIGHT...WITH THE INVERSION TRAPPING IT. SOME LOW STRATUS/FOG WOULD BE THE RESULT. FRONT IS APPROACHING...BUT LIKELY WON/T CLEAR FORECAST AREA UNTIL WELL AFTER 12Z. THE LIGHT WINDS AREN/T PARTICULAR DEEP THOUGH...INCREASING TO 10 KTS OR SO WITHIN A FEW HUNDRED FEET. STILL...ENOUGH FAVORABLE VARIABLES FOR FOG FORMATION THAT HAVE ADDED PATCHY-AREAS OF FOG TO THE FORECAST FOR TONIGHT. ALL SAID...CONDITIONS WILL HAVE TO BE MONITORED THROUGH THE OVERNIGHT HOURS. IF THE FRONT SLOWS UP...CAN/T RULE OUT THE POSSIBILITY OF HEADLINES FOR DENSE FOG...MOSTLY WEST OF THE CURRENT CLOUD SHIELD OVER WI. .LONG TERM... 250 PM CST MON NOV 19 2012 SYSTEM DEPARTS ON FRIDAY...WITH CYCLONIC FLOW ACROSS THE AREA. TEMPERATURES WILL BE BELOW NORMAL WITH HIGHS MAINLY IN THE 30S. MAIN PRECIPITATION CHANCE WILL BE ACROSS THE FAR NORTH. OTHERWISE...REMAINDER OF THE PERIOD WILL BE DOMINATED BY SEASONAL TO BELOW NORMAL TEMPERATURES. BEST CHANCE FOR ANY PRECIPITATION LOOKS BE ON MONDAY...BUT MODELS SHOWING SOME DIFFERENCES WITH A DEVELOPING TROUGH ACROSS THE CENTRAL CONUS. 19.12Z ECMWF SHOWS THIS FEATURE WITH CYCLOGENESIS OCCURRING...WHILE THE GFS KEEPS FLOW MORE ZONAL. IF THE ECMWF DOES VERIFY WILL HAVE TO WATCH THIS SYSTEM FOR PERIODS BEYOND MONDAY. && .AVIATION... 1035 PM CST MON NOV 19 2012 FOG IS GOING TO BE A BIGGER PLAYER IN THE FORECAST THAN FIRST THOUGHT. MESO MODELS CONTINUE TO POINT TO A RELATIVELY MOIST BOUNDARY LAYER UNDER AN INVERSION TONIGHT...WITH LIGHT SFC WINDS. FOG HAS ALREADY BEGUN TO DEVELOP WEST OF A CLOUD MASS THAT SAT ACROSS MOST OF WI...PER LATEST FOG/STRATUS SATELLITE IMAGERY. IN THE CLEAR REGION WEST OF THERE VSBYS HAVE ALREADY FALLEN BELOW 2 MILES IN MANY AREAS. BELIEVE VSBYS WILL DROP BELOW 1 MILE AT TIMES OVERNIGHT. PASSING SFC FRONT SHOULD USHER IN SOME DRIER AIR BY 12Z AT KRST...WHICH SHOULD HELP IMPROVE VSBYS. SOME NUMERICAL MODELS SUGGEST THAT FOG...POTENTIALLY DENSE...WOULD PERSIST THROUGH 15Z AT KRST. NOT BUYING THAT AT THIS MOMENT. A PERIOD OF IFR/LIFR LOOKS LIKELY AT KRST...AND PROBABLE AT KLSE. CAN/T RULE OUT THAT A DENSE FOG ADVISORY WILL BE NEEDED FOR PORTIONS OF THE REGION FOR EARLY TUE MORNING. WITH THE FOG WILL COME SOME STRATUS...ESPECIALLY AS THE FOG STARTS TO LIFT. RAP BUFKIT SOUNDINGS WOULD SCATTER OUT ANY CIGS BETWEEN 15-17Z. NOT ALL IS CLEAR CUT WITH VSBYS AND CIGS OVERNIGHT THOUGH...SO A CLOSE WATCH ON CONDITIONS WILL HAVE TO CONTINUE AND UPDATES MADE AS NEEDED. HIGH PRESSURE GRADUALLY BUILDS IN TUE AFTERNOON...BUT QUICKLY SLIDES SOUTHEAST OVERNIGHT. PRESSURE GRADIENT INCREASE BEHIND THE HIGH...AND COULD SEE SOME INCREASE IN WINDS TOWARD 12Z WED AS A RESULT. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 6AM-6AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 250 PM CST MON NOV 19 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RABERDING AVIATION.....RIECK CLIMATE......JONES/DB/AJ
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
629 AM EST TUE NOV 20 2012 .SYNOPSIS... THE REGION WILL REMAIN BETWEEN HIGH PRESSURE EXTENDING FROM NEW ENGLAND TO THE LOWER MISSISSIPPI VALLEY AND LOW PRESSURE OVER THE WESTERN ATLANTIC THROUGH THURSDAY. A COLD FRONT WILL THEN APPROACH FROM THE NORTHWEST LATE FRIDAY INTO SATURDAY...WITH HIGH PRESSURE REBUILDING FROM THE WEST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NO MAJOR CHANGES WERE MADE FOR THE SUNRISE UPDATE. MADE MINOR ADJUSTMENTS TO THE TIMING AND SOUTHWESTERN EXTENT OF LOW CLOUDS MOVING ACROSS THE CHARLESTON TRI-COUNTY AREA. HIGH PRESSURE WILL REMAIN ANCHORED OVER THE REGION TODAY AS A LARGE OCEANIC STORM MEANDERS WELL OF THE U.S. EAST COAST. A FAIRLY ZONAL FLOW WILL DOMINATE ALOFT AS SHORTWAVE ENERGY OVER THE NORTHERN MISSISSIPPI VALLEY BEGINS TO DIG SOUTH. THERE IS MUCH UNCERTAINTY ON HOW MUCH CLOUD COVER WILL OCCUR TODAY. CIRRUS BEING ENHANCED BY THE LEFT EXIT REGION OF A 115 KT JET STREAK WILL OVERSPREAD THE AREA FROM THE WEST LATER TODAY AS THE SUBTROPICAL JET AXIS DROPS FARTHER TO THE SOUTH AND EAST. MEANWHILE LOW CLOUDS SPREADING SOUTHWEST OUT OF NORTH CAROLINA ARE POISED TO MOVE INTO THE CHARLESTON TRI-COUNTY AREA BY SUNRISE. 975MB RUC MOISTURE PROGS SUGGEST MUCH OF THIS LOW-LEVEL CLOUD COVER WILL MIX OUT LATER THIS MORNING AS TEMPERATURES WARM WITH SKIES BECOMING PARTLY CLOUDY LATER TODAY ACROSS A GOOD PORTION OF THE AREA. HOWEVER...THERE REMAINS MUCH UNCERTAINTY ON EXACTLY HOW THE SKY COVER FORECAST WILL PLAY OUT WITH SOME GUIDANCE SUGGESTING SKIES WILL REMAIN MOSTLY CLOUDY FOR A GOOD PORTION OF THE DAY. LATER SHIFTS WILL MOST CERTAINLY HAVE TO MADE SOME ADJUSTMENTS AS THE DAY PROGRESSES. HIGHS WILL TOP OUT IN THE MID-UPPER 60S... WARMEST ACROSS THE SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... TONIGHT...SIMILAR TO MONDAY EVENING...SKIES SHOULD CLEAR A BIT WITH THE LOSS OF INSOLATION. MORE RAPID CLEARING IS EXPECTED TO OCCUR AFTER MIDNIGHT AS THE CORE OF THE AFOREMENTIONED SHORTWAVE DIGS TO THE WEST AND SOUTH...THUS SHUNTING THE SUBTROPICAL JET FAR TO THE SOUTH. EXPECT MOSTLY CLEAR SKIES TO DOMINATE BETWEEN MIDNIGHT AND SUNRISE WEDNESDAY. THE BOUNDARY LAYER SHOULD DECOUPLE FAIRLY QUICKLY THIS EVENING. CALM/LIGHT WINDS COUPLED WITH CLEARING SKIES WILL YIELD IMPROVING RADIATIONAL CONDITIONS OVERNIGHT. LOWS WILL RANGE FROM THE LOWER 40S WELL INLAND TO THE UPPER 40S AT THE COAST. WEDNESDAY AND THURSDAY...AN AMPLIFIED UPPER TROUGH WILL CROSS THE EAST COAST STATES WEDNESDAY MORNING AND MOVE OFFSHORE LATER IN THE DAY. WHILE THE DEPARTING UPPER TROUGH STRENGTHENS THE ATLANTIC SURFACE LOW FAR OUT TO SEA...SURFACE HIGH PRESSURE AND UPPER RIDGING WILL BUILD IN FROM THE WEST. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL THEN DOMINATE THE PATTERN OVER THE LAND AREAS THROUGH THURSDAY. LACKING ANY DEEP MOISTURE AS THE UPPER TROUGH PASSES THE REGION WEDNESDAY...FOLLOWED BY LITTLE UPPER LEVEL SUPPORT IN ITS WAKE...EXPECT DRY WEATHER TO PREVAIL THROUGH AT LEAST THURSDAY. HIGH TEMPERATURES WILL TREND BACK UP TOWARD SEASONAL NORMALS...REACHING THE MID TO UPPER 60S EACH AFTERNOON. NIGHTTIME LOW TEMPERATURES WILL ACTUALLY FALL BELOW NORMAL...AS DECOUPLING WINDS AND CLEAR SKIES SUPPORT IDEAL RADIATIONAL COOLING. LOW TEMPERATURES WEDNESDAY NIGHT WILL RANGE FROM AROUND 40 DEGREES WELL INLAND TO THE MID 40S NEAR THE COAST...AND THEN FALL TO EVEN COOLER LEVELS THURSDAY NIGHT IN THE UPPER 30S TO AROUND 40S MOST LOCATIONS AWAY FROM THE IMMEDIATE COAST. FRIDAY...AN UPPER LOW WELL TO THE NORTH WILL MOVE ACROSS THE GREAT LAKES REGION AND INTO THE NEW ENGLAND STATES LATE IN THE WEEK. THE RIDGING ALOFT WILL BREAK DOWN AHEAD OF THE MAIN TROUGH AXIS...ALLOWING A COLD FRONT TO RAPIDLY APPROACH FROM THE NORTHWEST. WEST TO NORTHWEST FLOW REMAIN PROMINENT THROUGHOUT THE PROFILE AS THE FRONT NEARS THE REGION...SUGGESTING THE FEATURE WILL LACK A DECENT TAP INTO MOISTURE. THUS EXPECT DRY CONDITIONS TO CONTINUE INTO FRIDAY. HIGH TEMPERATURES FRIDAY AFTERNOON COULD BE THE WARMEST OF THE PERIOD...LIKELY DUE TO PRE-FRONTAL COMPRESSION AND WINDS BRIEFLY BACKING TO THE SOUTHWEST. && .LONG TERM /SATURDAY THROUGH MONDAY/... A COLD FRONT WILL DROP SOUTHEAST THROUGH THE FORECAST AREA LATE FRIDAY INTO EARLY SATURDAY...AS AN UPPER TROUGH CROSSES THE MID ATLANTIC COASTLINE BY SATURDAY AFTERNOON. ALTHOUGH THE FRONT IS NOT EXPECTED TO BRING PRECIPITATION TO THE AREA...STRONG COLD ADVECTION WILL FOLLOW IN ITS WAKE THROUGH THE WEEKEND. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE MID TO UPPER 60S...THEN TREND EVEN COOLER IN THE LOWER 60S FOR SUNDAY AFTERNOON. BROAD SURFACE HIGH PRESSURE WILL STEADILY SLIP FROM THE LOWER MISSISSIPPI VALLEY TOWARD THE SOUTHEAST STATES THROUGH SUNDAY WITHIN PROGRESSIVE ZONAL FLOW ALOFT. ANOTHER LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST MONDAY THROUGH TUESDAY...BUT TIMING AND IMPACTS ARE TOO UNCERTAIN THIS FAR OUT. WILL THUS MAINTAIN RAIN CHANCES LESS THAN 15 PERCENT THROUGH THE EXTENDED PERIOD. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... KCHS...LOW CLOUDS ARE ON THE CUSP OF MOVING ACROSS THE TERMINAL. EXPECT LOW-END MVFR CIGS OF 1000-1200 FT TO OCCUR THROUGH ABOUT 15Z AFTER WHICH RAP SOUNDING SHOW THE LOW CLOUD DECK MIXING OUT. EXPECT VFR TO PREVAIL THROUGH THE REMAINDER OF THE 12Z TAF PERIOD ONCE THIS OCCURS. THERE IS A CHANCE THAT CIGS MAY BRIEFLY DROP TO IFR...BUT PROBABILITIES REMAIN FAIRLY LOW AND THERE ARE NO INDICATIONS THAT CIGS WILL DROP BELOW ALTERNATE MINIMUMS. KSAV...VFR. EXTENDED AVIATION OUTLOOK...THERE NO SIGNIFICANT ISSUES. && .MARINE... TODAY...THE MARINE AREA WILL SEE IMPROVING CONDITIONS THROUGH THE DAY. SEAS STILL LOOK TO REMAIN ABOVE 6 FT ACROSS THE CHARLESTON COUNTY COASTAL WATERS UNTIL LATE MORNING SO FLAGS WILL BE EXTENDED BY A FEW HOURS WITH SEAS 2-4 FT OVER THE REMAINING NEARSHORE LEGS. SEAS OF 6-8 FT ARE FORECAST TO REMAIN OVER THE GEORGIA OFFSHORE WATERS THROUGH THE AFTERNOON SO A SMALL CRAFT ADVISORY WILL REMAIN IN FORCE THERE. TONIGHT...SHOULD SEE A BIT OF AN INCREASE IN WINDS OVERNIGHT IN RESPONSE TO SHORTWAVE ENERGY APPROACHING FROM THE WEST. SPEEDS SHOULD BE NO HIGHER 15-20 KT OVER THE OFFSHORE WATERS WITH 10-15 KT CLOSER TO THE COAST. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS TO 5-7 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT OVERNIGHT FOR THE GEORGIA OFFSHORE LEG. WEDNESDAY THROUGH SATURDAY...WINDS AND SEAS WILL REMAIN ELEVATED THROUGH MID WEEK...AS THE PRESSURE GRADIENT REMAINS ENHANCED OVER THE WATERS BETWEEN BROAD HIGH PRESSURE INLAND AND A LOW PRESSURE SYSTEM FARTHER OUT IN THE ATLANTIC. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS FOR NEARSHORE WATERS. HOWEVER A COMBINATION OF NORTH/NORTHEAST WINDS...LONG PERIOD SWELLS AND COLD ADVECTION ASSOCIATED WITH BUILDING HIGH PRESSURE FROM THE WEST WILL ALLOW SMALL CRAFT ADVISORY CONDITIONS TO PERSIST OVER OUTER GEORGIA WATERS THROUGH MID WEEK AND POSSIBLY THROUGH LATE WEEK. CONDITIONS WILL THEN SLOWLY IMPROVE OVER ALL WATERS LATE WEEK...AS THE LOW PRESSURE SYSTEM SHIFTS FURTHER OFFSHORE AND THE PRESSURE GRADIENT WEAKENS ACCORDINGLY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR AMZ350. && $$ ST/79
AREA FORECAST DISCUSSION
NWS DES MOINES IA
654 AM CST TUE NOV 20 2012 .SHORT TERM /TODAY/... WEAK COLD FRONT IS PUSHING INTO SOUTHEAST IOWA. MOISTURE AHEAD OF THE FRONT...COMBINED WITH LIGHT WINDS AND CLEAR SKIES...HAS RESULTED IN WIDESPREAD DENSE FOG. ADVISORY REMAINS IN EFFECT FOR THE EASTERN PART OF THE CWA THROUGH 16Z. FOG WILL ERODE AWAY FROM THE WEST...BUT ONLY SLOW PROGRESS IS EXPECTED. HRRR IS QUITE AGGRESSIVE IN HOLDING ONTO THE FOG AND DO NOT EXPECTED IT TO LAST INTO THE AFTERNOON AS IT IS INDICATING. A COOLER START THIS MORNING THAN YESTERDAY WILL HELP KEEP TEMPS BELOW 60 ACROSS THE CWA TODAY. IN ADDITION...LIGHT WINDS WILL LIMIT MIXING DEPTH AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... RIDGE WILL BUILD IN BEHIND WEAK FRONTAL BOUNDARY FOR THE BEGINNING OF THE EXTENDED. UNDER RIDGE WITH SURFACE HIGH PRESSURE AND STRONG SOUTHERLY FLOW...TEMPERATURES WILL REMAIN WARM...WELL ABOVE NORMAL FOR NOVEMBER. HAVE KEPT TEMPERATURES NEAR GOING FORECAST...WITH WARMEST DAY WEDNESDAY AS WAA INCREASES AHEAD OF A FRONTAL BOUNDARY...AND CONDITIONS LOOK RIGHT FOR GOOD MIXING. COULD SEE TEMPERATURES POP A FEW DEGREES ABOVE GOING IN LOCATIONS FOR WEDNESDAY IF MIXING IS MAXIMIZED AS 85MB TEMPS WILL BE NEAR 14C ACROSS THE WEST. A WEAK FRONTAL BOUNDARY WILL PUSH ACROSS THE AREA FOR THURSDAY...WITH TEMPERATURES SLIGHTLY COOLER BEHIND THE BOUNDARY. HAVE LEFT SLIGHT CHANCE POPS ACROSS THE SOUTH FOR THURSDAY AS MOISTURE INCREASES. HOWEVER...DO NOT HAVE A LOT OF CONFIDENCE IN THESE CHANCE POPS AS MOISTURE IS SOMEWHAT LACKING. GFS IS MUCH MORE AGGRESSIVE WITH MOISTURE HEAD OF BOUNDARY...WITH NAM AND ECMWF MUCH LESS SO. HOWEVER...WITH FORCING ASSOCIATED WITH BOUNDARY COULD SEE SOME PRECIPITATION EVEN WITH LIMITED MOISTURE AND HAVE LEFT SLIGHT CHANCE POPS GOING. A MUCH STRONGER SYSTEM PUSHES THROUGH THURSDAY NIGHT...WITH A LARGE COOL DOWN IN STORE FOR THE END OF THE WEEK AS TEMPERATURES RETURN TO NEAR NORMAL. LOW PRESSURE SYSTEM WILL TRACK TO THE NORTH...AND COULD SEE SOME WRAP AROUND MOISTURE BRING LIGHT PRECIPITATION TO THE NORTH FRIDAY AND FRIDAY NIGHT...HOWEVER HAVE LEFT OUT ANY MENTION OF PRECIPITATION ATTM AS BEST FORCING WILL REMAIN NORTH INTO MINNESOTA. THE END OF THE PERIOD BECOMES A BIT TRICKY AS MODELS BUILD IN A WEAK RIDGE FOR THE WEEKEND...WITH TEMPERATURES AGAIN ABLE TO WARM NICELY. HOWEVER...THERE IS LITTLE AGREEMENT WITH SYSTEM FOR LATE IN THE WEEK. CURRENT MODEL TRENDS ARE TO HAVE A LOW PRESSURE SYSTEM PUSH ACROSS CANADA...BREAKING DOWN WEAK RIDGING. FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW PRESSURES SYSTEM WILL ALLOW FOR CHANCES FOR PRECIPITATION ACROSS THE CWA BY LATE MONDAY. HOWEVER...THERE IS NOT GOOD AGREEMENT IN THE TIMING AND LOCATION OF THIS SYSTEM AND DO NOT HAVE HIGH CONFIDENCE. THIS WILL NEED TO BE WATCHED CLOSELY. && .AVIATION...20/12Z FOG OVER EASTERN IA WILL SLOWLY IMPROVE DURING THE MORNING AS SOME MIXING TAKES PLACE BEHIND THE WEAK FRONTAL BOUNDARY. TIMING OF THE FOG ON THE HRRR SEEMS TOO SLOW WITH AN EXTENSIVE AREA HOLDING WELL PAST 18Z. GOES-R SIMULATED WF FCST PRODUCT SEEMS TO HAVE THE BEST HANDLE ON THE FOG TIMING AND FOLLOWED FAIRLY CLOSE WITH THE CLEARING. LITTLE ACTION IN THE REST OF THE TAF WITH WEAK HIGH PRESSURE RIDGE MOVING ACROSS THE STATE TODAY AND TONIGHT. && .DMX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BLACK HAWK- BREMER-BUTLER-DAVIS-GRUNDY-JASPER-MAHASKA-MARSHALL-POWESHIEK- TAMA-WAPELLO. && $$ SHORT TERM...MS NOV 12 LONG TERM...AWB AVIATION...MS NOV 12
AREA FORECAST DISCUSSION
NWS GOODLAND KS
411 AM MST TUE NOV 20 2012 .SHORT TERM...(TODAY THROUGH THURSDAY NIGHT) ISSUED AT 205 AM MST TUE NOV 20 2012 LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW A RIDGE EXTENDING NORTH ACROSS THE CENTRAL AND HIGH PLAINS WITH A LARGE TROUGH JUST OFF THE PACIFIC NORTHWEST COAST. TODAY-WEDNESDAY...WITH SHORTWAVE RIDGE IN PLACE TODAY AND SW FLOW ALOFT AND LARGE SCALE SUBSIDENCE ON WEDNESDAY DRY CONDITIONS ARE EXPECTED. WITH WAA ON EASTERN EXTENT OF LEE TROUGH STRENGTHENING THE NEXT FEW DAYS...WE SHOULD SEE TEMPERATURES IN THE 70S...WITH MID TO UPPER 70S POSSIBLE ON WED. BREEZY CONDITIONS WILL ALSO DEVELOP OVER PARTS OF THE AREA WITH GUSTS 20-30 MPH OVER PARTS OF THE AREA THE NEXT FEW AFTERNOONS. SEE FIRE WEATHER SECTION REGARDING POSSIBLE RED FLAG CONDITIONS THE NEXT FEW DAYS. THURSDAY-THURSDAY NIGHT...A STRONG TROUGH WILL MOVE ALONG THE CANADA US BORDER ON WED NIGHT AND THURSDAY...WITH A WEAKER LESS AMPLIFIED SHORTWAVE MOVING ACROSS THE SOUTHERN STREAM. THE NORTHERN TROUGH WILL KICK A COLD FRONT SOUTH OVER THE CWA THURSDAY...WITH WINDY CONDITIONS EXPECTED THROUGH WED AFTERNOON. WE COULD SEE WIND ADVISORY CRITERIA MET WITH BL WINDS 27-29KT AND H85 WINDS AROUND 40KT. ITS STILL TOO EARLY FOR AN NPW...HOWEVER I DID INCREASE WINDS TO REFLECT CURRENT THINKING. BEYOND FORCING IMMEDIATELY ALONG FRONT THE BEST LARGE SCALE ASCENT IS WELL NORTH AND SOUTHEAST. THE AIR MASS ALSO REMAINS VERY DRY ACROSS CWA...SO IM NOT ANTICIPATING ANY PRECIP. WITH FROPA DURING THE DAY HIGH TEMPS THU ARE TRICKY...HOWEVER THEY STILL SHOULD BE ABOVE NORMAL WITH A GRADIENT OF UPPER 50S IN THE NORTH TO MID/UPPER 60S IN THE SOUTH. NEAR TO BELOW NORMAL LOW TEMPS ARE EXPECTED THU NIGHT BEHIND THE FRONT WITH VALUES RANGING FROM THE UPPER TEENS TO MID 20S. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 205 AM MST TUE NOV 20 2012 AT LEAST EARLY ON MODELS ARE CONSISTENT WITH THE PREVIOUS FORECAST. COOLEST DAY WILL BE ON FRIDAY WITH MODERATION FOR SATURDAY. THEN CHANGES AND INCONSISTENCIES BEGIN AFTER THAT. NEWER MODEL DATA...ESPECIALLY THE ECMWF...IS NOW MORE PROGRESSIVE AND NOT AS STRONG WITH INCOMING UPPER TROUGH AT THE BEGINNING OF NEXT WEEK. GFS IS MUCH FASTER AND OLDER CANADIAN WAS MORE IN LINE WITH THE ECMWF. IN ADDITION THE MODEL DATA BRINGS IN NOT JUST ONE SHORTWAVE BUT A SERIES OF SHORTWAVE TROUGHS IN THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME PERIOD. THIS NEWER DATA IS FITTING THE PATTERN WE HAVE BEEN SEEING THIS SEASON AND IN FACT THIS YEAR. THE TROUGH DOES NOT COME THROUGH IN ONE NICE ORGANIZED SYSTEM BUT IN A SERIES OF SHORTWAVE TROUGHS. ENSEMBLE DATA SUPPORTS THE MORE PROGRESSIVE AND MULTIPLE SHORTWAVE SOLUTION AS WELL. THESE MULTIPLE SHORTWAVES HAVE TENDED TO SCOUR OUT THE DEEPER MOISTURE THAT THE MODELS THINK IS THERE. BELIEVE THAT THIS IS THE CASE HERE AS WELL. PLUS THE FRONT COMES THROUGH RATHER EARLY AND BY SUNDAY NIGHT IS A GREAT DISTANCE SOUTH OF THE AREA. NO SIGNIFICANT JET LIFT LOOKS TO BE INVOLVED AS WELL. AS A RESULT OF ALL THIS AND COLLABORATION...KEPT THE SMALL AREAS OF SLIGHT CHANCE POPS SUNDAY NIGHT AND MONDAY THE INIT GAVE ME AND REDUCED THE CHANCE POPS FOR MONDAY NIGHT DOWN TO SLIGHT CHANCE. BIG DIFFERENCES SHOWING UP IN THE LOW LEVEL THERMAL FIELD BEGINNING ON SUNDAY. THE ECMWF WAS NOT AS COLD AS THE FRIGID GFS. THE ECMWF TENDED TO BE IN THE MIDDLE OF THE ROAD AND ALSO MATCHED UP WELL WITH THE CRH_INIT SO LEFT THE TEMPERATURES ALONE AS RESULT OF THAT AND THE MODEL DIFFERENCES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 411 AM MST TUE NOV 20 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND KMCK. LIGHT SOUTHWEST WINDS WILL SHIFT TO THE SOUTH AND INCREASE AROUND MIDDAY AT KGLD AND EARLY THIS AFTERNOON AT KMCK AS A LEE TROUGH STRENGTHENS OVER EASTERN COLORADO. WIND GUSTS THIS AFTERNOON 20-25KT WILL BE POSSIBLE WITH STRONGEST GUSTS AT KGLD. WINDS WILL DIMINISH AROUND SUNSET AS DAYTIME HEATING COMES TO AN END. && .FIRE WEATHER... ISSUED AT 205 AM MST TUE NOV 20 2012 RH VALUES THIS AFTERNOON WILL RANGE FROM 15 TO 20 PERCENT. WITH WIND GUSTS 20-25 MPH WE WILL BE VERY CLOSE TO RFW CRITERIA. FOR NOW I AM NOT CONFIDENT WE WILL MEET THE 3HR REQUIREMENT...NO RFW PLANNED FOR NOW. CRITICAL FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE WED AFTERNOON WHEN RH VALUES BETWEEN 10 AND 20 PERCENT ARE EXPECTED ALONG AND NORTHWEST OF A LINE FROM OBERLIN TO LEOTI KS. WINDS ARE GOING TO BE LIGHTER IN THE WEST...WITH STRONGEST WINDS CURRENTLY WHERE RH VALUES ARE FORECAST TO BE HIGHER. MOST LOCATIONS SHOULD BE OUTSIDE OF RFW CRITERIA OTHER THAN A NARROW CORRIDOR SOUTH OF INTERSTATE 70 WHERE THERE COULD SEE A CROSSOVER OF RH/WIND. THIS IS GOING TO BE CLOSE...SO ITS WORTH MONITORING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...DR FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
513 AM CST TUE NOV 20 2012 .SHORT TERM...TODAY THROUGH THANKSGIVING 513 AM CST TUE NOV 20 2012 513 AM UPDATE...EXPANDING THE ADVISORY TO SOME SOUTHWEST WISCONSIN COUNTIES. SEE WWA SECTION BELOW. HAVE REMOVED OLMSTED AND MOWER COUNTIES AS SOME DRIER AIR ON NORTHWEST WINDS HAS CLEARED OUT MUCH OF THE FOG THERE. THIS DRIER AIR SHOULD KEEP MAKING ITS WAY SOUTHEAST...SO MORE COUNTIES MAY BE ABLE TO BE REMOVED. NEEDLESS TO SAY A RAPIDLY EVOLVING SITUATION HERE WITH THE FOG. PREVIOUS SHORT TERM DISCUSSION AT 326 AM... AT 3 AM...A PACIFIC COLD FRONT WAS MOVING INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA. AHEAD OF THIS FRONT...WIDESPREAD DENSE FOG HAS DEVELOPED ACROSS MUCH OF NORTHEAST IOWA AND PARTS OF SOUTHEAST MINNESOTA. AS THIS FRONT MOVES THROUGH...IT HAS BEEN LESSENING THE DEPTH OF THE FOG. THIS HAS RESULTED IN SOME IMPROVEMENT IN THE VISIBILITIES IN THE WAKE OF THIS FRONT. NOT QUITE SURE WHAT THIS FOG IS GOING TO DO ONCE IT MOVES INTO WESTERN WISCONSIN. WILL IT JUST BE A DECK OF STRATUS OR WILL WE SEE RAPID DEVELOPMENT OF DENSE FOG. DUE TO THIS UNCERTAINTY HELD OFF EXPANDING THE DENSE FOG ADVISORY FOR NOW. FOR TODAY EXPECT TO SEE THE LOW CLOUDS AND FOG WILL DISSIPATE THIS MORNING. THIS WILL LEAVE AFTERNOON MAINLY SUNNY. SINCE THIS FRONT IS A PACIFIC ONE...TEMPERATURES SHOULD ONLY BE A FEW DEGREES COOLER THAN MONDAY. ON WEDNESDAY...SOUTHWEST WINDS ALOFT WILL BRING VERY WARM AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. 925 MB TEMPERATURES CLIMB FROM 8C THIS AFTERNOON TO 14C BY WEDNESDAY AFTERNOON. THE WARM AIR BEING BROUGHT ISENTOPICALLY OFF OF THE HIGH PLAINS WILL RESULT IN THE DEVELOPMENT OF A STRONG CAP. THIS WILL INHIBIT THE DEVELOPMENT OF ANY PRECIPITATION. HIGH TEMPERATURES WILL BE IN THE MID AND UPPER 50S NORTH OF INTERSTATE 94 CORRIDOR /WHICH WILL BE CLOSE TO SOME RECORDS/. MEANWHILE THE REMAINDER OF THE AREA WILL BE IN THE LOWER AND MID 60S. ON THANKSGIVING...BOTH THE GFS AND ECMWF SUGGEST THAT A SHORT WAVE TROUGH WILL AFFECT SOUTHWEST WISCONSIN AND NORTHEAST IOWA. SOUNDINGS SUGGEST THAT THE AIRMASS WILL MOISTEN ENOUGH THAT THERE COULD BE SOME ELEVATED SHOWERS MOVE THROUGH THIS AREA. DUE TO THIS BEING A CONSISTENT SIGNAL...KEPT A LOW /20 PERCENT/ PRECIPITATION PROBABILITY IN THE FORECAST. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY 326 AM CST TUE NOV 20 2012 ON THURSDAY NIGHT AND FRIDAY...THE 20.00Z MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH WILL MOVE EAST THROUGH THE AREA. THIS SYSTEM WILL USHER IN MUCH COOLER AIR INTO THE REGION. TEMPERATURES WILL RUN NEAR TO SLIGHTLY BELOW NORMAL FROM FRIDAY INTO THE WEEKEND. THE MODELS ALSO SHOW THAT THERE WILL DEEP ENOUGH MOISTURE FOR A CHANCE OF SNOW ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR. MEANWHILE SOUTH OF THIS CORRIDOR...THE BUFKIT SOUNDINGS SHOW SOME WEAK OMEGA IN THE DENDRITIC GROWTH REGION AND THERE IS STEEP LAPSE RATES /AROUND 8C/KM / BETWEEN THE 950-850 MB. DUE TO THIS...INCLUDED SOME SCATTERED FLURRIES FOR THIS AREA FROM 29.09Z AND 29.12Z. GUSTY NORTHWEST WINDS AT 15 TO 20 KNOTS WILL PRODUCE WIND CHILLS FROM THE TEENS TO MID 20S. FOR EARLY NEXT WEEK AND BEYOND...UNCERTAINTY IS MUCH HIGHER THAN AVERAGE DUE TO THE FOLLOWING REASONS... 1. MADDEN JULIAN OSCILLATION /MJO/ - SEVERAL MODELS INCLUDING SOME RUNS OF THE ECMWF AND GFS TRY TO BRING A STRONG MJO SIGNAL INTO THE WESTERN PACIFIC BY EARLY NEXT WEEK. HOWEVER DURING THE PAST 3 DAYS...200 MB VELOCITY POTENTIAL ANOMALIES HAVE DRAMATICALLY DECREASED. IT WILL INTERESTING OVER THE WEEKEND WHETHER THIS OSCILLATION STRENGTHENS AS IT MOVES OVER 30C WATER IN THE WESTERN PACIFIC. 2. PHASE OF THE NORTH ATLANTIC OSCILLATION /NAO/ - FOR THE PAST WEEK THE MODELS HAVE BEEN STRUGGLING ON WHEN THE NAO WILL ONCE AGAIN BECOME NEGATIVE. CPC/S SPAGHETTI PLOT CONTINUES TO SHOW A WIDE RANGE OF SOLUTIONS FROM -1.5 TO 1. LOOKING AT THE 150 MB WIND ANOMALIES AND ALSO STRATOSPHERIC TEMPERATURES...DO NOT SEE ANY INDICATION OF A BLOCKING RIDGE DEVELOPING ANYWHERE IN THE NORTHERN HEMISPHERE. 3. CLIMATE MODELS - BOTH THE CFS VERSION 2 AND THE NORTH AMERICAN ENSEMBLE FORECASTING SYSTEM /NAEFS/ SHOW ABOVE- NORMAL TEMPERATURES FOR THE DAY 8 TO 14 TIME PERIOD. AS A RESULT...ANY COLD PERIOD SHOULD BE RATHER SHORT. THIS IS INCONSISTENT WITH SOME OF THE MODELS WHICH SHOW THAT SHOW A PERSISTENT TROUGH OVER THE AREA. WITH MIXED SIGNALS ACROSS THE GLOBE...VERY CAUTIOUS OF GRABBING ONTO ANY ONE MODEL SOLUTION...THUS...WILL KEEP PRECIPITATION PROBABILITIES LOW BEYOND DAY 5 UNTIL THERE IS A COHERENT DAY TO DAY SIGNAL. && .AVIATION... 1035 PM CST MON NOV 19 2012 FOG IS GOING TO BE A BIGGER PLAYER IN THE FORECAST THAN FIRST THOUGHT. MESO MODELS CONTINUE TO POINT TO A RELATIVELY MOIST BOUNDARY LAYER UNDER AN INVERSION TONIGHT...WITH LIGHT SFC WINDS. FOG HAS ALREADY BEGUN TO DEVELOP WEST OF A CLOUD MASS THAT SAT ACROSS MOST OF WI...PER LATEST FOG/STRATUS SATELLITE IMAGERY. IN THE CLEAR REGION WEST OF THERE VSBYS HAVE ALREADY FALLEN BELOW 2 MILES IN MANY AREAS. BELIEVE VSBYS WILL DROP BELOW 1 MILE AT TIMES OVERNIGHT. PASSING SFC FRONT SHOULD USHER IN SOME DRIER AIR BY 12Z AT KRST...WHICH SHOULD HELP IMPROVE VSBYS. SOME NUMERICAL MODELS SUGGEST THAT FOG...POTENTIALLY DENSE...WOULD PERSIST THROUGH 15Z AT KRST. NOT BUYING THAT AT THIS MOMENT. A PERIOD OF IFR/LIFR LOOKS LIKELY AT KRST...AND PROBABLE AT KLSE. CAN/T RULE OUT THAT A DENSE FOG ADVISORY WILL BE NEEDED FOR PORTIONS OF THE REGION FOR EARLY TUE MORNING. WITH THE FOG WILL COME SOME STRATUS...ESPECIALLY AS THE FOG STARTS TO LIFT. RAP BUFKIT SOUNDINGS WOULD SCATTER OUT ANY CIGS BETWEEN 15-17Z. NOT ALL IS CLEAR CUT WITH VSBYS AND CIGS OVERNIGHT THOUGH...SO A CLOSE WATCH ON CONDITIONS WILL HAVE TO CONTINUE AND UPDATES MADE AS NEEDED. HIGH PRESSURE GRADUALLY BUILDS IN TUE AFTERNOON...BUT QUICKLY SLIDES SOUTHEAST OVERNIGHT. PRESSURE GRADIENT INCREASE BEHIND THE HIGH...AND COULD SEE SOME INCREASE IN WINDS TOWARD 12Z WED AS A RESULT. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 7 AM-7 AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE THE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 513 AM CST TUE NOV 20 2012 WI...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR WIZ032>034- 041-042-053. MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ079-088- 095-096. IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011- 018-019-029-030. && $$ SHORT TERM...BOYNE/AJ LONG TERM...BOYNE AVIATION.....RIECK CLIMATE......JONES/DB/AJ/BOYNE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 PM CST TUE NOV 20 2012 .SHORT TERM /TONIGHT/... SFC HIGH CENTERED FROM SRN IA SOUTHWESTWARD TO SLIDE EAST SOUTHEAST TONIGHT...WITH SOUTHERLY FLOW AND WAA KICKING IN ALOFT. MOSTLY CLEAR SKIES EXPECTED TONIGHT WITH THE EXCEPTION OF THE FAR EAST...WHERE LOW STRATUS/FOG THAT IS CURRENTLY ACROSS SOUTHEASTERN IOWA EXPECTED TO BUILD BACK WEST/NORTHWARD THIS EVENING. THEREFORE LOW CLOUDS/FOG POSSIBLE FROM WATERLOO TO MARSHALLTOWN TO OTTUMWA OVERNIGHT...BASED ON THE HRRR OUTPUT FOR LOW CLOUDS. AS SFC RIDGE AXIS PUSHES THROUGH THE AREA AND WAA/SOUTHERLY FLOW INCREASES EXPECT MIN TEMPS TO START LEVELING OFF/POSSIBLY WARMING TOWARD SUNRISE. .LONG TERM /TONIGHT THROUGH TUESDAY/... HIGH PRESSURE WILL SHIFT OFF TO THE SOUTHEAST ON WEDNESDAY AS A BROAD AREA OF HIGH PRESSURE MOVES INTO THE DAKOTAS. THIS WILL INCREASE THE SOUTHERLY FLOW INTO IOWA AS THE THERMAL RIDGE LEANS INTO THE STATE. THESE CONDITIONS ALONG WITH VERY DRY AIR WILL BE CONDUCIVE TO GOOD WARMING. AN INVERSION NEAR 900 MB APPEARS TO BE A LIMITING FACTOR FROM ACHIEVING RECORD HIGH TEMPERATURES IN THE LOWER 70S HOWEVER EVEN IF THE INVERSION HOLDS...SUPER ADIABATIC LAPSE NEAR SURFACE SHOULD PUSH READINGS INTO THE MID TO UPPER 60S. THE THERMAL RIDGE STRENGTHENS WEDNESDAY NIGHT WITH SOUTHERLY WINDS CONTINUING. LOWS WILL BE WELL INTO THE 40S AT MOST LOCATIONS. THURSDAY WILL HAVE A WARM START WITH A COLD FRONT EXPECTED TO PASS THROUGH CENTRAL IOWA DURING THE AFTERNOON. AN SHORT WAVE WILL LIFT UP THROUGH THE SOUTHWEST FLOW AHEAD OF THE BOUNDARY AND WILL BRING THE CHANCE FOR A FEW SHOWERS OVER THE FAR SOUTHEAST. THE NMM AND ARW BASED MODELS ARE FARTHER SOUTHEAST WITH THIS SYSTEM THOUGH THE ECMWF AND GFS AFFECT IOWA MORE. GENERALLY ANY PRECIPITATION WILL BE LIGHT. THIS SYSTEM COULD BRING AN INCREASE IN CLOUDS AND MAY LIMIT TEMPERATURES A BIT. CENTRAL AND SOUTHEAST IOWA SHOULD REACH THE 60S BEFORE THE COLD FRONT PASSES THROUGH. STRONGER COLD ADVECTION NEAR 850 MB WILL ENHANCE MIXING BEHIND THE FRONTAL BOUNDARY WITH INCREASING SUBSIDENCE AIDING MOMENTUM TRANSFER OF WINDS TO THE SURFACE. MIXED LAYER WINDS OF 25 TO 35 KTS SHOULD PUSH SUSTAINED WINDS TO NEAR WIND ADVISORY CRITERIA MAINLY OVER THE NORTH AND WEST. ANOTHER SURGE OF COLD ADVECTION WILL DROP SOUTH THURSDAY NIGHT. FRIDAY WILL BE BLUSTERY AND COLD WITH BREEZY NORTHWEST WINDS. HIGHS WILL GENERALLY BE IN THE LOW TO MID 30S. HIGH PRESSURE MOVES ACROSS FRIDAY NIGHT. CURRENTLY HAVE LOWS A FEW DEGREES ABOVE MOS GUIDANCE FOR POTENTIAL MID TO HIGH LEVEL CLOUDS WITH INCREASING THETA-E ADVECTION THROUGH THOSE LEVELS. MINOR MODERATION SATURDAY INTO SUNDAY. A STRONGER COLD FRONT IS DUE TO ARRIVE MONDAY AND LEAD TO A COLD START TO NEXT WEEK. THE EXTENDED WILL BE MOSTLY DRY WITH THE POTENTIAL FOR VERY LIGHT RAIN OR SNOW EARLY NEXT WEEK. && .AVIATION...20/18Z MAINLY VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD...WITH THE EXCEPTION OF AT KOTM...WHERE SOME LINGERING LOW CLOUDS/HAZE MAY KEEP IT MVFR BRIEFLY THROUGH 19Z BEFORE ERODING/DISSIPATING. GOES-R SATELLITE FORECAST PRODUCT ALSO SUGGESTING LOW CLOUDS/FOG OVER MINNESOTA TO SPREAD SOUTHWARD LATE TONIGHT INDICATING POSSIBILITY OF IFR/MVFR CONDITIONS INTO KMCW. FOR NOW SATELLITE FORECAST PRODUCT SEEMS A BIT AGGRESSIVE COMPARED TO CURRENT SATELLITE TRENDS AND MODELS SHOWING ABSENCE OF LOW LEVEL MOISTURE THUS HAVE KEPT THE FORECAST VFR AT THIS TIME DUE TO UNCERTAINTY IN THE DEVELOPMENT OF THE IFR/MVFR CONDITIONS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MJB LONG TERM...DONAVON AVIATION...MJB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1110 AM CST TUE NOV 20 2012 .UPDATE... HAVE UPDATED THE FORECAST TO REMOVE FOG WORDING AND TOUCH UP SKY COVER GRIDS SOME AS LOW STRATUS CONTINUES TO DISSIPATE/ERODE OUT OF THE EASTERN CWA. ALSO HAVE DROPPED HIGHS A BIT ACROSS THE NORTH/EASTERN CWA WITH THE COOL START AND LINGERING LOW CLOUDS IN SOME PLACES. WEAK WAA ALOFT...BUT NORTHERLY WINDS AND STRONGER PUSH OF WARM AIR ALOFT NOT REALLY WORKING ITS WAY INTO THE CWA UNTIL LATE THIS AFTERNOON. THEREFORE JUST NUDGED THEM DOWN A BIT IN SOME PLACES NORTH/EAST. .SHORT TERM /TODAY/... WEAK COLD FRONT IS PUSHING INTO SOUTHEAST IOWA. MOISTURE AHEAD OF THE FRONT...COMBINED WITH LIGHT WINDS AND CLEAR SKIES...HAS RESULTED IN WIDESPREAD DENSE FOG. ADVISORY REMAINS IN EFFECT FOR THE EASTERN PART OF THE CWA THROUGH 16Z. FOG WILL ERODE AWAY FROM THE WEST...BUT ONLY SLOW PROGRESS IS EXPECTED. HRRR IS QUITE AGGRESSIVE IN HOLDING ONTO THE FOG AND DO NOT EXPECTED IT TO LAST INTO THE AFTERNOON AS IT IS INDICATING. A COOLER START THIS MORNING THAN YESTERDAY WILL HELP KEEP TEMPS BELOW 60 ACROSS THE CWA TODAY. IN ADDITION...LIGHT WINDS WILL LIMIT MIXING DEPTH AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... RIDGE WILL BUILD IN BEHIND WEAK FRONTAL BOUNDARY FOR THE BEGINNING OF THE EXTENDED. UNDER RIDGE WITH SURFACE HIGH PRESSURE AND STRONG SOUTHERLY FLOW...TEMPERATURES WILL REMAIN WARM...WELL ABOVE NORMAL FOR NOVEMBER. HAVE KEPT TEMPERATURES NEAR GOING FORECAST...WITH WARMEST DAY WEDNESDAY AS WAA INCREASES AHEAD OF A FRONTAL BOUNDARY...AND CONDITIONS LOOK RIGHT FOR GOOD MIXING. COULD SEE TEMPERATURES POP A FEW DEGREES ABOVE GOING IN LOCATIONS FOR WEDNESDAY IF MIXING IS MAXIMIZED AS 85MB TEMPS WILL BE NEAR 14C ACROSS THE WEST. A WEAK FRONTAL BOUNDARY WILL PUSH ACROSS THE AREA FOR THURSDAY...WITH TEMPERATURES SLIGHTLY COOLER BEHIND THE BOUNDARY. HAVE LEFT SLIGHT CHANCE POPS ACROSS THE SOUTH FOR THURSDAY AS MOISTURE INCREASES. HOWEVER...DO NOT HAVE A LOT OF CONFIDENCE IN THESE CHANCE POPS AS MOISTURE IS SOMEWHAT LACKING. GFS IS MUCH MORE AGGRESSIVE WITH MOISTURE HEAD OF BOUNDARY...WITH NAM AND ECMWF MUCH LESS SO. HOWEVER...WITH FORCING ASSOCIATED WITH BOUNDARY COULD SEE SOME PRECIPITATION EVEN WITH LIMITED MOISTURE AND HAVE LEFT SLIGHT CHANCE POPS GOING. A MUCH STRONGER SYSTEM PUSHES THROUGH THURSDAY NIGHT...WITH A LARGE COOL DOWN IN STORE FOR THE END OF THE WEEK AS TEMPERATURES RETURN TO NEAR NORMAL. LOW PRESSURE SYSTEM WILL TRACK TO THE NORTH...AND COULD SEE SOME WRAP AROUND MOISTURE BRING LIGHT PRECIPITATION TO THE NORTH FRIDAY AND FRIDAY NIGHT...HOWEVER HAVE LEFT OUT ANY MENTION OF PRECIPITATION ATTM AS BEST FORCING WILL REMAIN NORTH INTO MINNESOTA. THE END OF THE PERIOD BECOMES A BIT TRICKY AS MODELS BUILD IN A WEAK RIDGE FOR THE WEEKEND...WITH TEMPERATURES AGAIN ABLE TO WARM NICELY. HOWEVER...THERE IS LITTLE AGREEMENT WITH SYSTEM FOR LATE IN THE WEEK. CURRENT MODEL TRENDS ARE TO HAVE A LOW PRESSURE SYSTEM PUSH ACROSS CANADA...BREAKING DOWN WEAK RIDGING. FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW PRESSURES SYSTEM WILL ALLOW FOR CHANCES FOR PRECIPITATION ACROSS THE CWA BY LATE MONDAY. HOWEVER...THERE IS NOT GOOD AGREEMENT IN THE TIMING AND LOCATION OF THIS SYSTEM AND DO NOT HAVE HIGH CONFIDENCE. THIS WILL NEED TO BE WATCHED CLOSELY. && .AVIATION...20/18Z MAINLY VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD...WITH THE EXCEPTION OF AT KOTM...WHERE SOME LINGERING LOW CLOUDS/HAZE MAY KEEP IT MVFR BRIEFLY THROUGH 19Z BEFORE ERODING/DISSIPATING. GOES-R SATELLITE FORECAST PRODUCT ALSO SUGGESTING LOW CLOUDS/FOG OVER MINNESOTA TO SPREAD SOUTHWARD LATE TONIGHT INDICATING POSSIBILITY OF IFR/MVFR CONDITIONS INTO KMCW. FOR NOW SATELLITE FORECAST PRODUCT SEEMS A BIT AGGRESSIVE COMPARED TO CURRENT SATELLITE TRENDS AND MODELS SHOWING ABSENCE OF LOW LEVEL MOISTURE THUS HAVE KEPT THE FORECAST VFR AT THIS TIME DUE TO UNCERTAINTY IN THE DEVELOPMENT OF THE IFR/MVFR CONDITIONS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MS NOV 12 LONG TERM...AWB AVIATION...MJB UPDATE...MJB
AREA FORECAST DISCUSSION...UPDATED
NWS DES MOINES IA
1005 AM CST TUE NOV 20 2012 .UPDATE... HAVE UPDATED THE FORECAST TO REMOVE FOG WORDING AND TOUCH UP SKY COVER GRIDS SOME AS LOW STRATUS CONTINUES TO DISSIPATE/ERODE OUT OF THE EASTERN CWA. ALSO HAVE DROPPED HIGHS A BIT ACROSS THE NORTH/EASTERN CWA WITH THE COOL START AND LINGERING LOW CLOUDS IN SOME PLACES. WEAK WAA ALOFT...BUT NORTHERLY WINDS AND STRONGER PUSH OF WARM AIR ALOFT NOT REALLY WORKING ITS WAY INTO THE CWA UNTIL LATE THIS AFTERNOON. THEREFORE JUST NUDGED THEM DOWN A BIT IN SOME PLACES NORTH/EAST. .SHORT TERM /TODAY/... WEAK COLD FRONT IS PUSHING INTO SOUTHEAST IOWA. MOISTURE AHEAD OF THE FRONT...COMBINED WITH LIGHT WINDS AND CLEAR SKIES...HAS RESULTED IN WIDESPREAD DENSE FOG. ADVISORY REMAINS IN EFFECT FOR THE EASTERN PART OF THE CWA THROUGH 16Z. FOG WILL ERODE AWAY FROM THE WEST...BUT ONLY SLOW PROGRESS IS EXPECTED. HRRR IS QUITE AGGRESSIVE IN HOLDING ONTO THE FOG AND DO NOT EXPECTED IT TO LAST INTO THE AFTERNOON AS IT IS INDICATING. A COOLER START THIS MORNING THAN YESTERDAY WILL HELP KEEP TEMPS BELOW 60 ACROSS THE CWA TODAY. IN ADDITION...LIGHT WINDS WILL LIMIT MIXING DEPTH AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... RIDGE WILL BUILD IN BEHIND WEAK FRONTAL BOUNDARY FOR THE BEGINNING OF THE EXTENDED. UNDER RIDGE WITH SURFACE HIGH PRESSURE AND STRONG SOUTHERLY FLOW...TEMPERATURES WILL REMAIN WARM...WELL ABOVE NORMAL FOR NOVEMBER. HAVE KEPT TEMPERATURES NEAR GOING FORECAST...WITH WARMEST DAY WEDNESDAY AS WAA INCREASES AHEAD OF A FRONTAL BOUNDARY...AND CONDITIONS LOOK RIGHT FOR GOOD MIXING. COULD SEE TEMPERATURES POP A FEW DEGREES ABOVE GOING IN LOCATIONS FOR WEDNESDAY IF MIXING IS MAXIMIZED AS 85MB TEMPS WILL BE NEAR 14C ACROSS THE WEST. A WEAK FRONTAL BOUNDARY WILL PUSH ACROSS THE AREA FOR THURSDAY...WITH TEMPERATURES SLIGHTLY COOLER BEHIND THE BOUNDARY. HAVE LEFT SLIGHT CHANCE POPS ACROSS THE SOUTH FOR THURSDAY AS MOISTURE INCREASES. HOWEVER...DO NOT HAVE A LOT OF CONFIDENCE IN THESE CHANCE POPS AS MOISTURE IS SOMEWHAT LACKING. GFS IS MUCH MORE AGGRESSIVE WITH MOISTURE HEAD OF BOUNDARY...WITH NAM AND ECMWF MUCH LESS SO. HOWEVER...WITH FORCING ASSOCIATED WITH BOUNDARY COULD SEE SOME PRECIPITATION EVEN WITH LIMITED MOISTURE AND HAVE LEFT SLIGHT CHANCE POPS GOING. A MUCH STRONGER SYSTEM PUSHES THROUGH THURSDAY NIGHT...WITH A LARGE COOL DOWN IN STORE FOR THE END OF THE WEEK AS TEMPERATURES RETURN TO NEAR NORMAL. LOW PRESSURE SYSTEM WILL TRACK TO THE NORTH...AND COULD SEE SOME WRAP AROUND MOISTURE BRING LIGHT PRECIPITATION TO THE NORTH FRIDAY AND FRIDAY NIGHT...HOWEVER HAVE LEFT OUT ANY MENTION OF PRECIPITATION ATTM AS BEST FORCING WILL REMAIN NORTH INTO MINNESOTA. THE END OF THE PERIOD BECOMES A BIT TRICKY AS MODELS BUILD IN A WEAK RIDGE FOR THE WEEKEND...WITH TEMPERATURES AGAIN ABLE TO WARM NICELY. HOWEVER...THERE IS LITTLE AGREEMENT WITH SYSTEM FOR LATE IN THE WEEK. CURRENT MODEL TRENDS ARE TO HAVE A LOW PRESSURE SYSTEM PUSH ACROSS CANADA...BREAKING DOWN WEAK RIDGING. FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW PRESSURES SYSTEM WILL ALLOW FOR CHANCES FOR PRECIPITATION ACROSS THE CWA BY LATE MONDAY. HOWEVER...THERE IS NOT GOOD AGREEMENT IN THE TIMING AND LOCATION OF THIS SYSTEM AND DO NOT HAVE HIGH CONFIDENCE. THIS WILL NEED TO BE WATCHED CLOSELY. && .AVIATION...20/12Z FOG OVER EASTERN IA WILL SLOWLY IMPROVE DURING THE MORNING AS SOME MIXING TAKES PLACE BEHIND THE WEAK FRONTAL BOUNDARY. TIMING OF THE FOG ON THE HRRR SEEMS TOO SLOW WITH AN EXTENSIVE AREA HOLDING WELL PAST 18Z. GOES-R SIMULATED WRF FCST PRODUCT SEEMS TO HAVE THE BEST HANDLE ON THE FOG TIMING AND FOLLOWED FAIRLY CLOSE WITH THE CLEARING. LITTLE ACTION IN THE REST OF THE TAF WITH WEAK HIGH PRESSURE RIDGE MOVING ACROSS THE STATE TODAY AND TONIGHT. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MS NOV 12 LONG TERM...AWB AVIATION...MS NOV 12 UPDATE...MJB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1040 AM MST TUE NOV 20 2012 .SHORT TERM...(TODAY THROUGH THURSDAY NIGHT) ISSUED AT 205 AM MST TUE NOV 20 2012 LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW A RIDGE EXTENDING NORTH ACROSS THE CENTRAL AND HIGH PLAINS WITH A LARGE TROUGH JUST OFF THE PACIFIC NORTHWEST COAST. TODAY-WEDNESDAY...WITH SHORTWAVE RIDGE IN PLACE TODAY AND SW FLOW ALOFT AND LARGE SCALE SUBSIDENCE ON WEDNESDAY DRY CONDITIONS ARE EXPECTED. WITH WAA ON EASTERN EXTENT OF LEE TROUGH STRENGTHENING THE NEXT FEW DAYS...WE SHOULD SEE TEMPERATURES IN THE 70S...WITH MID TO UPPER 70S POSSIBLE ON WED. BREEZY CONDITIONS WILL ALSO DEVELOP OVER PARTS OF THE AREA WITH GUSTS 20-30 MPH OVER PARTS OF THE AREA THE NEXT FEW AFTERNOONS. SEE FIRE WEATHER SECTION REGARDING POSSIBLE RED FLAG CONDITIONS THE NEXT FEW DAYS. THURSDAY-THURSDAY NIGHT...A STRONG TROUGH WILL MOVE ALONG THE CANADA US BORDER ON WED NIGHT AND THURSDAY...WITH A WEAKER LESS AMPLIFIED SHORTWAVE MOVING ACROSS THE SOUTHERN STREAM. THE NORTHERN TROUGH WILL KICK A COLD FRONT SOUTH OVER THE CWA THURSDAY...WITH WINDY CONDITIONS EXPECTED THROUGH WED AFTERNOON. WE COULD SEE WIND ADVISORY CRITERIA MET WITH BL WINDS 27-29KT AND H85 WINDS AROUND 40KT. ITS STILL TOO EARLY FOR AN NPW...HOWEVER I DID INCREASE WINDS TO REFLECT CURRENT THINKING. BEYOND FORCING IMMEDIATELY ALONG FRONT THE BEST LARGE SCALE ASCENT IS WELL NORTH AND SOUTHEAST. THE AIR MASS ALSO REMAINS VERY DRY ACROSS CWA...SO IM NOT ANTICIPATING ANY PRECIP. WITH FROPA DURING THE DAY HIGH TEMPS THU ARE TRICKY...HOWEVER THEY STILL SHOULD BE ABOVE NORMAL WITH A GRADIENT OF UPPER 50S IN THE NORTH TO MID/UPPER 60S IN THE SOUTH. NEAR TO BELOW NORMAL LOW TEMPS ARE EXPECTED THU NIGHT BEHIND THE FRONT WITH VALUES RANGING FROM THE UPPER TEENS TO MID 20S. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 205 AM MST TUE NOV 20 2012 AT LEAST EARLY ON MODELS ARE CONSISTENT WITH THE PREVIOUS FORECAST. COOLEST DAY WILL BE ON FRIDAY WITH MODERATION FOR SATURDAY. THEN CHANGES AND INCONSISTENCIES BEGIN AFTER THAT. NEWER MODEL DATA...ESPECIALLY THE ECMWF...IS NOW MORE PROGRESSIVE AND NOT AS STRONG WITH INCOMING UPPER TROUGH AT THE BEGINNING OF NEXT WEEK. GFS IS MUCH FASTER AND OLDER CANADIAN WAS MORE IN LINE WITH THE ECMWF. IN ADDITION THE MODEL DATA BRINGS IN NOT JUST ONE SHORTWAVE BUT A SERIES OF SHORTWAVE TROUGHS IN THE SUNDAY NIGHT THROUGH MONDAY NIGHT TIME PERIOD. THIS NEWER DATA IS FITTING THE PATTERN WE HAVE BEEN SEEING THIS SEASON AND IN FACT THIS YEAR. THE TROUGH DOES NOT COME THROUGH IN ONE NICE ORGANIZED SYSTEM BUT IN A SERIES OF SHORTWAVE TROUGHS. ENSEMBLE DATA SUPPORTS THE MORE PROGRESSIVE AND MULTIPLE SHORTWAVE SOLUTION AS WELL. THESE MULTIPLE SHORTWAVES HAVE TENDED TO SCOUR OUT THE DEEPER MOISTURE THAT THE MODELS THINK IS THERE. BELIEVE THAT THIS IS THE CASE HERE AS WELL. PLUS THE FRONT COMES THROUGH RATHER EARLY AND BY SUNDAY NIGHT IS A GREAT DISTANCE SOUTH OF THE AREA. NO SIGNIFICANT JET LIFT LOOKS TO BE INVOLVED AS WELL. AS A RESULT OF ALL THIS AND COLLABORATION...KEPT THE SMALL AREAS OF SLIGHT CHANCE POPS SUNDAY NIGHT AND MONDAY THE INIT GAVE ME AND REDUCED THE CHANCE POPS FOR MONDAY NIGHT DOWN TO SLIGHT CHANCE. BIG DIFFERENCES SHOWING UP IN THE LOW LEVEL THERMAL FIELD BEGINNING ON SUNDAY. THE ECMWF WAS NOT AS COLD AS THE FRIGID GFS. THE ECMWF TENDED TO BE IN THE MIDDLE OF THE ROAD AND ALSO MATCHED UP WELL WITH THE CRH_INIT SO LEFT THE TEMPERATURES ALONE AS RESULT OF THAT AND THE MODEL DIFFERENCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1036 AM MST TUE NOV 20 2012 VFR CONDITIONS ARE EXPECTED AT KGLD AND KMCK FOR THE NEXT 24 HOURS. RELATIVELY LIGHT SOUTH TO SOUTHWEST WINDS ARE EXPECTED WITH A SURFACE TROUGH IN EASTERN COLORADO. && .FIRE WEATHER... ISSUED AT 205 AM MST TUE NOV 20 2012 RH VALUES THIS AFTERNOON WILL RANGE FROM 15 TO 20 PERCENT. WITH WIND GUSTS 20-25 MPH WE WILL BE VERY CLOSE TO RFW CRITERIA. FOR NOW I AM NOT CONFIDENT WE WILL MEET THE 3HR REQUIREMENT...NO RFW PLANNED FOR NOW. CRITICAL FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE WED AFTERNOON WHEN RH VALUES BETWEEN 10 AND 20 PERCENT ARE EXPECTED ALONG AND NORTHWEST OF A LINE FROM OBERLIN TO LEOTI KS. WINDS ARE GOING TO BE LIGHTER IN THE WEST...WITH STRONGEST WINDS CURRENTLY WHERE RH VALUES ARE FORECAST TO BE HIGHER. MOST LOCATIONS SHOULD BE OUTSIDE OF RFW CRITERIA OTHER THAN A NARROW CORRIDOR SOUTH OF INTERSTATE 70 WHERE THERE COULD SEE A CROSSOVER OF RH/WIND. THIS IS GOING TO BE CLOSE...SO ITS WORTH MONITORING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...032 FIRE WEATHER...DR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
320 PM EST TUE NOV 20 2012 .SYNOPSIS... A WEAKENING COLD FRONT OVER NORTHWEST OHIO WILL DISSIPATE AS IT MOVES ACROSS THE LOCAL AREA TONIGHT. HIGH PRESSURE WILL RETURN FOR WEDNESDAY AND THE THANKSGIVING HOLIDAY. A STRONGER COLD FRONT IS EXPECTED TO ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... RADAR CONTINUES TO SHOW SOME WEAK RETURNS WITH A LEGITIMATE SHOWER OVER RICHLAND COUNTY. A FEW SHOWERS HAVE COME AND GONE THE PAST HOUR OR SO. WILL GO WITH A 20 POP OVER MUCH OF THE AREA THROUGH 00Z OR SO TO COVER ANY NEW DEVELOPMENT. LATEST HRRR INDICATES THAT THIS IS A REASONABLE SCENARIO. WHAT IS LEFT OF THE COLD FRONT HAS MOVED INTO NW OH AND SHOULD BE COMPLETELY GONE BY LATE EVENING. HAVE SEEN SOME BREAKS IN THE CLOUDS RECENTLY BUT THINK THE FLAVOR OF THE NIGHT WILL BE MOSTLY CLOUDY AS STRATO CU BEHIND THE FRONT MOVES INTO THE AREA. GUIDANCE TEMPS LOOK REASONABLE. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/... WE SHOULD SEE A DECREASE IN THE CLOUDS TOMORROW WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES BY LATE AFTERNOON. TEMPS WILL BE A DEGREE OR TWO WARMER THAN TODAY GIVEN THE SUNSHINE. EVEN WARMER READINGS ARE EXPECTED FOR THANKSGIVING AS THE RIDGE AXIS WILL BE JUST EAST OF THE AREA. ABUNDANT SUNSHINE IS ALSO EXPECTED. THE MODELS CONTINUE TO BE IN DECENT AGREEMENT WITH THE COLD FRONTAL PASSAGE ON FRIDAY. THE FRONT SHOULD BE INTO NW PA BY EARLY AFTERNOON. ALL OF THE NEW GUIDANCE IS SHOWING A LINE OF SHOWERS ALONG THE FRONT AND HAVE BUMPED POPS UP SLIGHTLY. EXPECT THAT LATER SHIFTS MAY EVENTUALLY NEED TO GO WITH LIKELY OR HIGHER WORDING. GOOD COLD AIR ADVECTION IS EXPECTED BEHIND THE FRONT WITH 850 MB TEMPS DIPPING TO AROUND NEG 10 BY 12Z SAT. WILL NEED TO HANG ON TO SOME LAKE EFFECT PRECIP FRIDAY NIGHT OVER MOST OF THE AREA. HAVE USED A BLEND OF GUIDANCE TEMPS DURING THE PERIOD. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A DECENT LAKE EFFECT SHSN EVENT STILL LOOKS IN ORDER FOR SAT INTO SAT NIGHT TAPERING TO MAINLY FLURRIES BY SUN MORNING AS RIDGE OF HIGH PRESSURE MOVES OVERHEAD. THE RIDGE SHOULD BRIEFLY STOP THE PRECIP THEN ANOTHER SYSTEM IS EXPECTED TO APPROACH THE AREA WITH MOISTURE ARRIVING MONDAY. THE MODELS DIFFER GREATLY BY TUE SO WILL CONTINUE A SMALL CHANCE FOR RAIN OR SNOW INTO TUE THUS LEANING MORE TOWARD THE ECMWF AS THE GFS LOOKS TO BE TRENDING MORE THAT WAY TOO. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... VFR SHOULD PREVAIL MOST OF THE TIME THROUGH THE TAF PERIOD. CIGS MAY LOWER IN THE WEST CLOSER TO MVFR LEVELS INTO TONIGHT. PATCHY MVFR FOG MAY DEVELOP AT SOME TAF SITES LATE TONIGHT. WINDS WILL STAY LIGHT. OUTLOOK...NON-VFR SHOULD OCCUR FRIDAY SHIFTING TO MAINLY THE SNOWBELT FOR SAT AND SAT NIGHT WITH SHRA CHANGING TO SHSN. VFR SHOULD RETURN MOST SITES SUNDAY. && .MARINE... A RIDGE ACROSS THE LAKE WILL SHIFT SOUTHEAST LATE WEDNESDAY AND THAT WILL ALLOW A SOUTHWEST FLOW TO DEVELOP. THE SOUTHWEST FLOW WILL CONTINUE TO INCREASE THROUGH THURSDAY NIGHT BUT WITH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE NEAR 0C...STABLE...IT WILL BE TOUGH FOR THOSE STRONGER WINDS TO GET TO THE LAKE SURFACE. A SMALL CRAFT ADVISORY MAY BE NEEDED BY LATE THURSDAY NIGHT WITH WINDS OF 15 TO 25 KNOTS. GOING WITH THE SLOWER GFS/ECMWF SOLUTIONS WHICH HAS THE COLD FRONTAL PASSAGE AND A LITTLE STRONGER WINDS FOR LATE FRIDAY. IT IS POSSIBLE THAT WINDS COULD BE CLOSE TO GALE FORCE MAINLY ON THE EAST END OF THE LAKE FRIDAY AFTERNOON. AT THIS TIME IT LOOKS VERY MARGINAL AND BRIEF...THIS WILL HAVE TO BE MONITORED. THE WATER LEVEL WILL ALSO HAVE TO BE WATCHED ON THE WEST END OF THE LAKE FRIDAY AND FRIDAY NIGHT. NONE THE LESS A SMALL CRAFT ADVISORY WILL LIKELY BE NEED FROM LATE THURSDAY NIGHT THROUGH EARLY SATURDAY NIGHT. LATE SATURDAY NIGHT AND ON SUNDAY THE WINDS SHIFT TO THE SOUTHWEST AS A RIDGE MOVES EAST OF THE LAKE. ANOTHER FRONT OR TROF WILL MOVE ACROSS THE LAKE LATE SUNDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...ADAMS AVIATION...TK MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
302 PM CST TUE NOV 20 2012 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT 301 PM CST TUE NOV 20 2012 MAIN FORECAST CONCERN IS ON CLOUDS/FOG POTENTIAL TONIGHT...TEMPERATURES THROUGH THE PERIOD AND RAIN CHANCES FOR THANKSGIVING DAY. VISIBLE SATELLITE IMAGERY AT 18Z SHOWS AN AREA OF FOG ALONG THE MISSISSIPPI RIVER AND ACROSS SOUTHWEST WISCONSIN AND EASTERN IOWA. THIS AREA HAS BEEN SHRINKING OVER THE PAST SEVERAL HOURS AND EXPECT IT TO DISSIPATE BY EVENING. OTHERWISE SKIES WERE CLEAR AROUND THE AREA. 20.12Z MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH THE PERIOD. NAM IS THE FASTEST SOLUTION IN REGARD TO THE FRONTAL MOVEMENT ON THANKSGIVING DAY AND WENT MORE WITH A MODEL CONSENSUS WITH ITS MOVEMENT ACROSS THE FORECAST AREA. IN THE NEAR TERM...PROBLEM IS ON FOG AND LOW CLOUD POTENTIAL AGAIN TONIGHT. RAP BUFKIT SOUNDINGS SHOW MOISTURE BEING TRAPPED UNDER THE STRENGTHENING INVERSION TONIGHT...BUT NAM WANTS TO SCOUR THINGS OUT WITH DRIER AIR FILTERING IN FROM THE WEST. HOWEVER...FEEL RAP MAYBE MORE ACCURATE AS GRADIENT LOOKS TO BE QUITE WEAK UNTIL LATER TONIGHT WHEN THE WINDS PICK UP ACROSS THE WEST. FEEL WIDESPREAD FOG IS AGAIN LIKELY...MAINLY IN AREAS ALONG AND EAST OF THE MISSISSIPPI RIVER. ATTENTION THEN TURNS TO BUILDING UPPER RIDGE ACROSS THE AREA WEDNESDAY. 925MB TEMPERATURES WILL WARM INTO THE LOWER TO MIDDLE TEENS CELSIUS BY AFTERNOON AND THUS EXPECT VERY WARM TEMPERATURES. MIXING POTENTIAL LOOKS TO BE BETWEEN 925MB AND 950MB AND USING THE MIX DOWN TOOL RESULTS IN A 10 DEGREE DIFFERENCE BETWEEN MIXING TO 925MB AND 950MB. THE CAVEAT WILL BE LINGERING CLOUDS AND FOG EXPECTED INTO THE MID MORNING HOURS THAT MAY PREVENT FULL WARMING. NONE THE LESS FORECAST IS BASED ON CLOUDS/FOG DISSIPATING BY MID MORNING AND COMBINED WITH A MILD START WILL STILL MAKE IT INTO THE MID 50S ACROSS THE NORTH TO THE MID 60S IN THE CENTRAL AND SOUTH. ANOTHER MILD NIGHT IS EXPECTED WEDNESDAY NIGHT WITH SOUTHERLY LOW LEVEL FLOW CONTINUING AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL REMAIN WEST OF THE AREA THROUGH THE OVERNIGHT HOURS. ANOTHER MILD DAY IS EXPECTED THANKSGIVING DAY AS THE FRONTAL PASSAGE LOOKS LIKE IT WILL OCCUR DURING THE AFTERNOON HOURS. AS MENTIONED PREVIOUSLY...NAM IS THE FASTEST SOLUTION AND USED A MODEL CONSENSUS. IN EITHER CASE...THE COLDER AIR LAGS BEHIND AND WILL NOT ARRIVE UNTIL THURSDAY NIGHT. GFS CONTINUES TO BE THE ONLY MODEL THAT GENERATES SHOWERS OVER SOUTHWEST WISCONSIN...WITH THE GEM AND ECMWF KEEPING THE RAIN JUST SOUTH OF THE AREA. WILL CONTINUE LOWER END PROBABILITIES ACROSS FAR SOUTHWEST WISCONSIN. STRONG COLD ADVECTION EXPECTED BEHIND THE FRONT THURSDAY NIGHT ALONG WITH A TIGHTENING PRESSURE GRADIENT. STRATUS LOOKS TO ADVECT SOUTHWARD AS THE NIGHT WEARS ON...ESPECIALLY ACROSS THE NORTHERN HALF OF THE FORECAST AREA. THESE CLOUDS WILL THEN CONTINUE INTO FRIDAY. PRESSURE GRADIENT RATHER TIGHT FRIDAY AND LOOKS LIKE A BLUSTERY AND COLD DAY WITH TEMPERATURES ONLY CLIMBING A FEW DEGREES FROM THE MORNING LOWS. BETTER CHANCES FOR LIGHT SHOW/RAIN WILL BE ACROSS THE NORTH AND WILL CONTINUE THE LOWER END PROBABILITIES IN THESE AREAS. HIGH PRESSURE THEN BUILDS EASTWARD FROM THE PLAINS FRIDAY NIGHT AND WITH CLEAR SKIES EXPECTED...LOWS WILL BE IN THE TEENS TO LOWER 20S. .LONG TERM... 301 PM CST TUE NOV 20 2012 MEDIUM RANGE MODELS DO SHOW SOME DIFFERENCES IN THIS TIME FRAME. 20.12Z ECMWF HAS BACKED OFF ON A NEGATIVELY TILTED TROUGH DEVELOPING EARLY NEXT WEEK AND NOW HAS MAINLY A ZONAL FLOW REGIME. GFS AND ECMWF DO DIFFER WITH SOME SUBTLE WAVES EXPECTED TO TRANSLATE THROUGH THE FLOW FROM SUNDAY THROUGH TUESDAY. SURFACE HIGH PRESSURE WILL DOMINATE THE PATTERN SATURDAY...BUT AFTER THAT CONFIDENCE IS RATHER LOW IN ANY ONE SOLUTION AND THUS HAVE WENT WITH THE MODEL CONSENSUS. TEMPERATURES LOOK TO REMAIN BELOW NORMAL THROUGH THE PERIOD...WITH HIGHS MAINLY IN THE 30S WITH LOWS IN THE TEENS AND 20S. && .AVIATION...THIS AFTERNOON THROUGH WEDNESDAY 1125 AM CST TUE NOV 20 2012 A VERY PROBLEMATIC PERIOD WITH ABUNDANT LOW LEVEL MOISTURE TRAPPED UNDER A RATHER STRONG INVERSION NEAR 925 MB. LIGHT WINDS/LIMITED MIXING THIS TIME OF YEAR HAVE RESULTED IN PERSISTENT IFR/LIFR DENSE FOG 25-50 MILES EITHER SIDE OF THE MS RIVER. SFC OBS/VIS IMAGERY SHOWING ONLY A VERY SLOW EROSION/IMPROVEMENT OF THE FOG AS OF MID-DAY. SOME IMPROVEMENT FROM LIFR TO IFR IN THIS BAND OF LOW CLOUDS/FOG EXPECTED THRU THE AFTERNOON. RADIATIONAL COOLING/LIGHT WINDS UNDER THE INVERSION WILL ALLOW THE FOG TO RE-THICKEN AGAIN TONIGHT...AT LEAST THRU THE EVENING HOURS. SFC PRESSURE GRADIENT TIGHTENS LATER TONIGHT AND INTO WED...ALLOWING FOR BOUNDARY LAYER MIXING UNDER THE INVERSION. THIS EXPECTED TO RESULT IN MORE IFR/LIFR STRATUS AND 1-3SM VSBYS IN BR VS. M1/4SM IN FG IF THE WINDS WERE TO STAY LIGHT/VARIABLE. GRADIENT CONTINUES TO TIGHTEN WED WITH WARMER/ DRIER AIR ADVECTING/MIXING IN FROM THE SOUTHWEST. GIVEN THE TIME OF YEAR...IFR/MVFR VSBYS AND SOME IFR CIGS LIKELY TO PERSIST THRU MUCH OF WED MORNING BEFORE CONDITIONS IMPROVE WITH DEEPER MIXING/EROSION OF THE INVERSION FOR THE MID-DAY/AFTERNOON HOURS. && .CLIMATE... 200 AM CST SUN NOV 18 2012 RECORD HIGH TEMPERATURES FOR WEDNESDAY/21ST AND THURSDAY/22ND. COOP SITES ARE 7 AM-7 AM HIGHS...THUS 22ND HIGHS ARE 21.12Z TO 22.12Z. LA CROSSE AND ROCHESTER ARE THE ONLY NON-COOP SITES. FORECAST HIGH TEMPERATURES SUGGEST SOME OF THE RECORDS BELOW MAY BE TIED OR BROKEN. LOCATION WEDNESDAY/21ST THURSDAY/22ND LA CROSSE WI 72/1990 59/1963 SPARTA WI 65/1990 70/1990 MEDFORD WI 59/1913 65/1990 LANCASTER WI 66/2003 66/1898 MAUSTON WI 67/2003 66/1990 ROCHESTER MN 69/1990 65/1913 AUSTIN MN 70/1990 58/1966 WINONA DAM 5A MN 60/2003 60/2001 WABASHA MN 61/1908 59/1908 CHARLES CITY IA 71/1990 62/1966 OELWEIN IA 71/1990 62/1966 DECORAH IA 71/1990 62/1908 && .ARX WATCHES/WARNINGS/ADVISORIES... 301 PM CST TUE NOV 20 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RABERDING LONG TERM...RABERDING AVIATION.....RRS CLIMATE......JONES/DB/AJ/BOYNE